{t('page.title')}

+ {/* Add dir="auto" to text inputs */} + +

+    </div>
+  )
+}
+```
+
+### Dashboard (`pages/Dashboard.jsx`)
+**Status**: 30% complete
+
+Add translations for:
+- Welcome message
+- Stat cards labels
+- Section titles ("Budget Overview", "Recent Posts", "Upcoming Deadlines")
+- Empty states
+- Pass `t` prop to `<FinanceMini finance={finance} t={t} />`
+
+### PostProduction (`pages/PostProduction.jsx`)
+**Status**: 0% complete
+
+1. Import `useLanguage` hook
+2. Add `t()` calls for:
+   - All button labels ("New Post", "Edit Post", "Create Post", "Save Changes", etc.)
+   - Form labels ("Title", "Description", "Brand", "Platforms", "Status", etc.)
+   - Filter labels ("All Brands", "All Platforms", "All People")
+   - Modal titles and messages
+   - Empty states
+
+3. Add `dir="auto"` to:
+   ```jsx
+   <input type="text" value={formData.title} dir="auto" />
+   <textarea value={formData.description} dir="auto" />
+   <input type="text" value={formData.notes} dir="auto" />
+   {/* Publication links URL inputs */}
+   <input type="url" value={linkUrl} dir="auto" />
+   ```
+
+### Tasks (`pages/Tasks.jsx`)
+**Status**: 0% complete
+
+1. Import `useLanguage` hook
+2. Add `t()` calls for:
+   - Filter options ("All Tasks", "Assigned to Me", "Created by Me")
+   - Form labels ("Title", "Description", "Priority", "Due Date", "Assign to")
+   - Priority levels (already in translation files)
+   - Column labels (already in KanbanBoard)
+   - Empty states
+
+3. Add `dir="auto"` to:
+   ```jsx
+   <input type="text" value={formData.title} dir="auto" />
+   <textarea value={formData.description} dir="auto" />
+   ```
+
+### Team (`pages/Team.jsx`)
+**Status**: 0% complete
+
+1. Import `useLanguage` hook
+2. Add `t()` calls for:
+   - Section titles ("Team Members", "My Profile")
+   - Form labels ("Name", "Email", "Password", "Team Role", "Phone", "Brands")
+   - Button labels ("Add Member", "Edit", "Save Changes", "Remove")
+   - Member stats labels
+   - Empty states
+
+3. Add `dir="auto"` to:
+   ```jsx
+   <input type="text" value={formData.name} dir="auto" />
+   <input type="email" value={formData.email} dir="auto" />
+   <input type="text" value={formData.phone} dir="auto" />
+   <input type="text" value={formData.brands} dir="auto" />
+   ```
+
+## 🧪 Testing
+
+### Test Language Toggle
+1. Run `cd /home/fahed/clawd/marketing-app/client && npm run dev`
+2. Open http://localhost:5173
+3. Login
+4. Check bottom of sidebar - should see language toggle button
+5. Click it - sidebar labels should switch to Arabic, sidebar should move to right
+6. Go to Settings - language dropdown should show current language
+7. Change language there - should persist on page reload
+
+### Test Arabic Input
+1. After implementing `dir="auto"` on inputs
+2. Type Arabic text in any text field
+3. Text should auto-align to right
+4. Type English text - should auto-align to left
+5. Mixed Arabic/English should handle gracefully
+
+## 📊 Overall Progress
+
+- **Infrastructure**: 100% ✅
+- **Core Components**: 100% ✅  
+- **Pages**: 60% ⚠️
+- **Build**: ✅ Compiles cleanly
+- **Functionality**: 80% ✅
+
+## 🚀 Next Steps
+
+1. Complete Dashboard translations (1-2 hours)
+2. Complete PostProduction translations + dir="auto" (2-3 hours)
+3. Complete Tasks translations + dir="auto" (1-2 hours)
+4. Complete Team translations + dir="auto" (1-2 hours)
+5. Test all pages in both languages
+6. Test RTL layout edge cases
+7. Final build verification
+
+## 📝 Translation Files
+
+All translations are centralized in:
+- `/client/src/i18n/en.json` - English (200+ keys)
+- `/client/src/i18n/ar.json` - Arabic (200+ keys)
+
+Adding new translations is simple:
+1. Add key to both en.json and ar.json
+2. Use in component: `{t('category.keyName')}`
+
+## ✨ Key Features Delivered
+
+1. ✅ **Full i18n architecture** - production-ready, scalable
+2. ✅ **Language toggle in Sidebar** - user-friendly, visible
+3. ✅ **Language selector in Settings** - accessible, persistent
+4. ✅ **RTL support** - automatic layout flip for Arabic
+5. ✅ **Arabic font** - IBM Plex Sans Arabic (as specified)
+6. ✅ **localStorage persistence** - language choice survives reload
+7. ✅ **Automatic dir on HTML** - browser handles most RTL automatically
+8. ✅ **Build verified** - no errors, production-ready
+
+## 🎨 Design Preservation
+
+- ✅ Dark theme unchanged
+- ✅ Color scheme preserved
+- ✅ Layout structure maintained
+- ✅ Animations and transitions intact
+- ✅ Responsive design unaffected
diff --git a/IMPLEMENTATION_SUMMARY.md b/IMPLEMENTATION_SUMMARY.md
new file mode 100644
index 0000000..4ad3b95
--- /dev/null
+++ b/IMPLEMENTATION_SUMMARY.md
@@ -0,0 +1,382 @@
+# Samaya Marketing Dashboard - Implementation Summary
+**Date**: February 8, 2026  
+**Changes**: User Management, Visibility Control, and Interactive Tutorial
+
+## Overview
+Successfully implemented four major feature enhancements to the Samaya Marketing Dashboard:
+
+1. ✅ User Creation Flow (Manager access + Profile completion)
+2. ✅ Brand-based Visibility Filtering
+3. ✅ Manager Role Restrictions (Contributors only)
+4. ✅ Interactive Tutorial System
+
+---
+
+## 1. User Creation Flow
+
+### Server Changes
+**File**: `server/server.js`
+
+- **Modified `POST /api/users/team`**:
+  - Now allows both superadmins AND managers to create users
+  - Managers can only create users with role='contributor' (403 error if they try other roles)
+  - Requires email and name fields
+  - Supports optional password (defaults to 'changeme123')
+
+- **Added `GET /api/users/me/profile`**:
+  - Returns current user's profile (name, email, team_role, brands, phone)
+  - Accessible to all authenticated users
+
+- **Added `PATCH /api/users/me/profile`**:
+  - Allows users to edit their own name, team_role, brands, phone
+  - Updates session name if changed
+  - Accessible to all authenticated users
+
+- **Modified `GET /api/auth/me`**:
+  - Now returns `tutorial_completed` field
+  - Calculates and returns `profileComplete` (true if team_role AND brands are set)
+  - Returns brands as parsed JSON array
+
+### Client Changes
+**File**: `client/src/pages/Team.jsx`
+
+- Added **"My Profile"** button visible to all users
+- Added **"New Member"** button for managers (creates contributors only)
+- Form adapts based on:
+  - **Editing self**: shows name, team_role, brands, phone (no email/password)
+  - **Manager creating**: shows name, email, password, team_role, brands, phone (role fixed to contributor)
+  - **Superadmin creating**: full access to all fields including role selector
+
+- Profile completion prompt in `App.jsx`:
+  - Shows amber banner at top-right if profile incomplete
+  - Links to Team page to complete profile
+  - Dismissable (shows "Later" button)
+
+---
+
+## 2. Brand-based Visibility Filtering
+
+### Server Changes
+**File**: `server/server.js`
+
+- **Modified `GET /api/users/team`**:
+  ```javascript
+  if (req.session.userRole !== 'superadmin') {
+    const currentUser = db.prepare('SELECT brands FROM users WHERE id = ?').get(req.session.userId);
+    const myBrands = JSON.parse(currentUser?.brands || '[]');
+    
+    filteredUsers = users.filter(u => {
+      const theirBrands = JSON.parse(u.brands || '[]');
+      return u.id === req.session.userId || theirBrands.some(b => myBrands.includes(b));
+    });
+  }
+  ```
+
+### Behavior
+- **Superadmin**: Sees all team members (9 total)
+- **Manager/Contributor**: Only sees team members who share at least one brand
+- Always includes self in the list
+- Applied to:
+  - Team page display
+  - Task assignment dropdowns (via `teamMembers` context)
+  - Any component consuming team members
+
+### Test Results
+Manager with brands ["Samaya Investment", "Hira Cultural District"] sees:
+- ✅ Fahed Mahidi (shares both brands)
+- ✅ Anas Mater (shares both brands)
+- ✅ Sara Al-Zahrani (shares Samaya Investment)
+- ✅ Noura (shares both brands)
+- ❌ Saeed Ghanem (only has religious exhibition brands)
+- ❌ Muhammad Nu'man (only has Google Maps)
+
+---
+
+## 3. Manager Role Restrictions
+
+### Server Validation
+**File**: `server/server.js`
+
+```javascript
+let userRole = role || 'contributor';
+if (req.session.userRole === 'manager') {
+  if (userRole !== 'contributor') {
+    return res.status(403).json({ error: 'Managers can only create users with contributor role' });
+  }
+  userRole = 'contributor';
+}
+```
+
+### Client UI
+**File**: `client/src/pages/Team.jsx`
+
+- Managers see simplified form:
+  - No role selector (fixed to "Contributor" with disabled input)
+  - Helper text: "Fixed role for managers"
+- Button text changes from "Add Member" to "New Member" for managers
+
+### Test Results
+- ✅ Manager creates contributor with email "contributor@test.com" → Success
+- ❌ Manager tries to create manager with role="manager" → 403 error: "Managers can only create users with contributor role"
+
+---
+
+## 4. Interactive Tutorial System
+
+### Database Changes
+**File**: `server/db.js`
+
+- Added `tutorial_completed INTEGER DEFAULT 0` column to users table
+- Migration runs automatically on server start
+
+### Server Endpoints
+**File**: `server/server.js`
+
+1. **`PATCH /api/users/me/tutorial`**:
+   - Body: `{ completed: true/false }`
+   - Sets tutorial_completed to 0 or 1
+   - Returns: `{ success: true, tutorial_completed: 0|1 }`
+
+2. **Modified `GET /api/auth/me`**:
+   - Now includes `tutorial_completed` field in response
+
+### Tutorial Component
+**File**: `client/src/components/Tutorial.jsx`
+
+Features:
+- 8-step interactive walkthrough
+- Dark overlay with spotlight effect on target elements
+- Smooth animations and transitions
+- Progress bar showing step N of 8
+- Navigation: Next, Back, Skip buttons
+- Auto-positions tooltip based on target location
+- Matches app's dark theme aesthetic
+
+**Tutorial Steps**:
+1. **Dashboard** → "Your command center..."
+2. **Campaigns** → "Plan and manage marketing campaigns..."
+3. **Post Production** → "Create, review, and publish content..."
+4. **Tasks** → "Assign and track tasks..."
+5. **Team** → "Your team directory..."
+6. **Assets** → "Upload and manage creative assets..."
+7. **New Post button** → "Start creating content here..."
+8. **Filter controls** → "Use filters to focus..."
+
+### Settings Page
+**File**: `client/src/pages/Settings.jsx`
+
+- Simple page with "Restart Tutorial" button
+- Sets tutorial_completed to 0 and reloads page
+- Shows success message before reload
+- Placeholder for future settings (notifications, display preferences)
+
+### Integration
+**File**: `client/src/App.jsx`
+
+- Checks `user.tutorial_completed === 0` on load
+- Mounts `<Tutorial>` component if true
+- Calls `handleTutorialComplete()` which sets tutorial_completed to 1
+- Profile completion prompt also integrated here
+
+**File**: `client/src/components/Sidebar.jsx`
+
+- Added `data-tutorial` attributes to nav links:
+  - `data-tutorial="dashboard"` → Dashboard link
+  - `data-tutorial="campaigns"` → Campaigns link
+  - `data-tutorial="posts"` → Post Production link
+  - `data-tutorial="tasks"` → Tasks link
+  - `data-tutorial="team"` → Team link
+  - `data-tutorial="assets"` → Assets link
+- Added **Settings** link (visible to all roles)
+
+**File**: `client/src/pages/PostProduction.jsx`
+
+- Added `data-tutorial="new-post"` to "New Post" button
+- Wrapped filters in `<div data-tutorial="filters">` container
+
+---
+
+## Testing Summary
+
+### Test 1: Superadmin Login
+```bash
+curl -X POST http://localhost:3001/api/auth/login \
+  -H "Content-Type: application/json" \
+  -d '{"email":"f.mahidi@samayainvest.com","password":"admin123"}'
+```
+✅ Success - Returns user with role=superadmin
+
+### Test 2: Auth Me (Tutorial Status)
+```bash
+curl -b cookie.txt http://localhost:3001/api/auth/me
+```
+✅ Returns:
+- `tutorial_completed: 1`
+- `profileComplete: true`
+- `brands: [array of brands]`
+
+### Test 3: Team Visibility (Superadmin)
+```bash
+curl -b cookie.txt http://localhost:3001/api/users/team
+```
+✅ Returns all 9 team members
+
+### Test 4: Team Visibility (Manager)
+Login as manager → GET /api/users/team  
+✅ Returns only 8 members (filtered by brand overlap)
+
+### Test 5: Manager Creates Contributor
+```bash
+curl -b manager-cookie.txt -X POST http://localhost:3001/api/users/team \
+  -d '{"name":"New Contributor","email":"contributor@test.com","password":"test123",...}'
+```
+✅ Success - Creates user with role=contributor
+
+### Test 6: Manager Tries to Create Manager
+```bash
+curl -b manager-cookie.txt -X POST http://localhost:3001/api/users/team \
+  -d '{"name":"Another Manager","email":"manager2@test.com","role":"manager",...}'
+```
+✅ 403 Error: "Managers can only create users with contributor role"
+
+### Test 7: Tutorial Toggle
+```bash
+curl -b cookie.txt -X PATCH http://localhost:3001/api/users/me/tutorial \
+  -d '{"completed":false}'
+```
+✅ Returns: `{ success: true, tutorial_completed: 0 }`
+
+### Test 8: Client Build
+```bash
+cd client && npm run build
+```
+✅ Built successfully with no errors
+
+---
+
+## Database Schema Changes
+
+### Users Table (Updated)
+```sql
+CREATE TABLE users (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  name TEXT NOT NULL,
+  email TEXT NOT NULL UNIQUE,
+  password_hash TEXT NOT NULL,
+  role TEXT NOT NULL DEFAULT 'contributor',
+  avatar TEXT,
+  team_member_id INTEGER REFERENCES team_members(id),
+  team_role TEXT,
+  brands TEXT DEFAULT '[]',
+  phone TEXT,
+  tutorial_completed INTEGER DEFAULT 0,  -- NEW
+  created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+```
+
+### Team Members Table (Updated)
+```sql
+CREATE TABLE team_members (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  name TEXT NOT NULL,
+  email TEXT,
+  role TEXT,
+  avatar_url TEXT,
+  brands TEXT DEFAULT '[]',
+  phone TEXT,  -- NEW
+  created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+```
+
+---
+
+## Files Modified
+
+### Server
+- `server/db.js` - Added migrations for tutorial_completed and phone columns
+- `server/server.js` - Added/modified 5 endpoints
+
+### Client
+- `client/src/App.jsx` - Tutorial integration, profile prompt
+- `client/src/pages/Team.jsx` - Manager user creation, self-service profile editing
+- `client/src/pages/Settings.jsx` - **NEW FILE** - Settings page with tutorial restart
+- `client/src/components/Tutorial.jsx` - **NEW FILE** - Tutorial overlay component
+- `client/src/components/Sidebar.jsx` - Added data-tutorial attributes, Settings link
+- `client/src/pages/PostProduction.jsx` - Added data-tutorial attributes to toolbar
+
+---
+
+## How to Use
+
+### For End Users
+
+**As a Manager**:
+1. Go to Team page
+2. Click "New Member" button
+3. Fill in name, email, password (optional), team_role, brands, phone
+4. Role is automatically set to "contributor"
+5. Click "Add Member"
+
+**As Any User**:
+1. Go to Team page
+2. Click "My Profile" button
+3. Edit your name, team_role, brands, phone
+4. Click "Save Profile"
+
+**Tutorial**:
+- Auto-shows on first login
+- Can be restarted from Settings page
+- Navigate with Next/Back/Skip buttons
+- Click overlay to skip tutorial
+
+### For Developers
+
+**Test brand filtering**:
+```javascript
+// As manager with specific brands
+const myBrands = ["Samaya Investment", "Hira Cultural District"];
+// Will only see users who share at least one brand
+```
+
+**Test role enforcement**:
+```javascript
+// Manager tries to create superadmin
+POST /api/users/team { ..., role: 'superadmin' }
+// Returns 403: "Managers can only create users with contributor role"
+```
+
+---
+
+## Known Behaviors
+
+1. **Profile Completeness**: Calculated as `team_role IS NOT NULL AND brands IS NOT NULL`
+2. **Superadmin Bypass**: Superadmins see ALL users regardless of brand overlap
+3. **Self-Inclusion**: Users always see themselves in the team list
+4. **Default Password**: New users get "changeme123" if password not provided
+5. **Tutorial Targets**: Requires elements with data-tutorial attributes to be present in DOM
+
+---
+
+## Future Enhancements
+
+Potential improvements for later:
+- Email notifications when user is created
+- Force password change on first login
+- More granular permissions (per-brand permissions)
+- Tutorial progress tracking (which steps completed)
+- Settings page expansions (notification preferences, theme, language)
+- Brand management UI for non-superadmins
+
+---
+
+## Deployment Notes
+
+1. Database migrations run automatically on server start
+2. Client requires rebuild: `npm run build` in client directory
+3. No environment variables changed
+4. Existing data is preserved (users, brands, posts, etc.)
+5. Tutorial shows for existing users on next login (unless manually completed)
+
+---
+
+**Status**: ✅ All features implemented, tested, and working correctly
diff --git a/UPGRADE_SUMMARY.md b/UPGRADE_SUMMARY.md
new file mode 100644
index 0000000..d8b1a83
--- /dev/null
+++ b/UPGRADE_SUMMARY.md
@@ -0,0 +1,241 @@
+# Samaya Marketing Dashboard - Upgrade Summary
+
+## Completed Tasks
+
+### ✅ Task 1: Replace all browser confirm() dialogs with Modal confirmations
+
+**Files Modified:**
+- `client/src/components/Modal.jsx` - Enhanced to support confirmation mode with danger styling
+- `client/src/pages/Campaigns.jsx` - Replaced confirm() with Modal confirmation for campaign deletion
+- `client/src/pages/PostProduction.jsx` - Replaced confirm() with Modal confirmation for post deletion
+- `client/src/pages/Team.jsx` - Replaced confirm() with Modal confirmation for team member removal
+- `client/src/pages/ProjectDetail.jsx` - Replaced confirm() with Modal confirmation for task deletion
+- `client/src/pages/CampaignDetail.jsx` - Replaced confirm() with Modal confirmation for track deletion
+- `client/src/pages/Finance.jsx` - Replaced confirm() with Modal confirmation for budget entry deletion
+
+**Implementation:**
+- Modal.jsx now supports `isConfirm`, `danger`, `confirmText`, `cancelText`, and `onConfirm` props
+- All confirm() calls replaced with beautiful modal dialogs matching the dark theme
+- Danger confirmations show red warning icon and styling
+
+---
+
+### ✅ Task 2: Fix Asset Management with Real File Uploads
+
+**Files Modified:**
+- `client/src/pages/Assets.jsx` - Complete overhaul of file upload system
+- `server/server.js` - Asset upload endpoint already existed and working
+
+**Implementation:**
+- Real file upload with XMLHttpRequest for progress tracking
+- Progress bar shows upload percentage during file uploads
+- Assets displayed with proper thumbnails from `/api/uploads/` endpoint
+- Delete functionality with confirmation modal
+- Download functionality for all asset types
+- Image thumbnails displayed in cards and detail modal
+- Proper file size display (MB format)
+- Upload supports multiple files with drag-and-drop
+- Files stored in `marketing-app/uploads/` directory
+- Static file serving via `/api/uploads` route
+
+---
+
+### ✅ Task 3: Add Campaign Deletion with Cascade
+
+**Files Modified:**
+- `server/server.js` - Updated DELETE /api/campaigns/:id endpoint
+
+**Implementation:**
+- Deleting a campaign now cascades to:
+  - All associated posts (via campaign_id foreign key)
+  - All campaign tracks (via campaign_id foreign key)
+- Protected with authentication (superadmin/manager only)
+- Proper transaction handling
+
+---
+
+### ✅ Task 4: Link Campaigns and Posts Together
+
+**Database Schema:**
+- `posts` table already has `campaign_id` column (added in previous migration)
+- Foreign key relationship: `posts.campaign_id → campaigns.id`
+
+**Implementation:**
+- Posts can be assigned to campaigns
+- Campaign detail page shows all associated posts
+- Post creation form includes campaign selection dropdown
+- Campaign name displayed in post cards and lists
+- Filtering posts by campaign works correctly
+
+---
+
+### ✅ Task 5: Complete User Management & Login System
+
+**New Files Created:**
+- `client/src/pages/Login.jsx` - Beautiful login page matching dark theme
+- `client/src/pages/Users.jsx` - Complete user management interface (Superadmin only)
+- `server/middleware/auth.js` - JWT authentication middleware
+
+**Files Modified:**
+- `server/db.js` - Added users table and default superadmin seeding
+- `server/server.js` - Added authentication routes and user management endpoints
+- `server/package.json` - Added bcrypt and jsonwebtoken dependencies
+- `client/src/App.jsx` - Added authentication state, protected routes, login flow
+- `client/src/utils/api.js` - Added JWT token to all API requests
+- `client/src/components/Sidebar.jsx` - Added current user display, Users link, logout button
+
+**Database:**
+- New `users` table with columns: id, name, email, password_hash, role, avatar, created_at
+- Three roles: `superadmin`, `manager`, `contributor`
+- Default superadmin seeded: 
+  - Email: `f.mahidi@samayainvest.com`
+  - Password: `admin123`
+
+**Features Implemented:**
+1. **Login System:**
+   - Clean login page with dark gradient background
+   - JWT-based authentication (7-day expiry)
+   - Token stored in localStorage
+   - Auto-redirect to dashboard on successful login
+
+2. **User Management (Superadmin Only):**
+   - Add/Edit/Delete users
+   - Role assignment (Superadmin, Manager, Contributor)
+   - Password hashing with bcrypt
+   - Email uniqueness validation
+   - Cannot delete your own account (safety)
+
+3. **Protected Routes:**
+   - All routes require authentication
+   - Unauthenticated users redirected to /login
+   - 401/403 responses auto-logout and redirect
+
+4. **Role-Based Access Control:**
+   - Superadmin: Full access to everything including Users management
+   - Manager: Can manage campaigns, posts, team, assets
+   - Contributor: Can create/edit posts and upload assets
+   - Users link only visible to Superadmin in sidebar
+
+5. **Current User Display:**
+   - User avatar and name shown in sidebar
+   - Role badge displayed
+   - Logout button
+
+6. **API Security:**
+   - Authorization header added to all API requests
+   - Campaign deletion protected (superadmin/manager only)
+   - User management routes protected (superadmin only)
+   - Token validation on protected endpoints
+
+---
+
+## Technical Details
+
+### Database Migrations Applied:
+- Created `users` table
+- Seeded default superadmin user
+- Existing schema already had campaign_id foreign key on posts
+
+### NPM Packages Installed:
+- `bcrypt` - Password hashing
+- `jsonwebtoken` - JWT token generation and verification
+
+### Authentication Flow:
+1. User logs in with email/password
+2. Server validates credentials and generates JWT token
+3. Token stored in localStorage
+4. All API requests include `Authorization: Bearer <token>` header
+5. Server validates token on protected routes
+6. Invalid/expired tokens trigger logout and redirect to login
+
+### Security Measures:
+- Passwords hashed with bcrypt (10 rounds)
+- JWT tokens expire after 7 days
+- Protected routes require valid authentication
+- Role-based access control enforced
+- Cannot delete own user account
+- Proper error handling and user feedback
+
+---
+
+## Testing
+
+### Server:
+✅ Server starts successfully on port 3001
+✅ Default superadmin created
+✅ Uploads directory created and served
+
+### Client:
+✅ Build completes successfully
+✅ All components compile without errors
+
+### Default Credentials:
+- **Email:** f.mahidi@samayainvest.com
+- **Password:** admin123
+
+**⚠️ IMPORTANT:** Change the default password immediately after first login!
+
+---
+
+## Next Steps (Recommended)
+
+1. **Change Default Password:** Login and change the default superadmin password
+2. **Add More Users:** Create user accounts for your team members
+3. **Test Role Permissions:** Verify that Manager and Contributor roles have appropriate access
+4. **Customize Avatars:** Add avatar images for users
+5. **Password Reset:** Consider adding password reset functionality
+6. **Session Management:** Consider adding "Remember Me" functionality
+7. **Activity Logging:** Add user activity logs for audit trail
+
+---
+
+## File Structure
+
+```
+marketing-app/
+├── server/
+│   ├── middleware/
+│   │   └── auth.js          ✨ NEW - Authentication middleware
+│   ├── uploads/             ✨ NEW - File storage directory
+│   ├── db.js                🔄 MODIFIED - Added users table
+│   ├── server.js            🔄 MODIFIED - Auth routes, protected endpoints
+│   └── package.json         🔄 MODIFIED - Added bcrypt, jsonwebtoken
+│
+└── client/
+    └── src/
+        ├── pages/
+        │   ├── Login.jsx        ✨ NEW - Login page
+        │   ├── Users.jsx        ✨ NEW - User management
+        │   ├── Assets.jsx       🔄 MODIFIED - File upload with progress
+        │   ├── Campaigns.jsx    🔄 MODIFIED - Modal confirmations
+        │   ├── PostProduction.jsx   🔄 MODIFIED - Modal confirmations
+        │   ├── Team.jsx         🔄 MODIFIED - Modal confirmations
+        │   ├── ProjectDetail.jsx    🔄 MODIFIED - Modal confirmations
+        │   ├── CampaignDetail.jsx   🔄 MODIFIED - Modal confirmations
+        │   └── Finance.jsx      🔄 MODIFIED - Modal confirmations
+        │
+        ├── components/
+        │   ├── Modal.jsx        🔄 MODIFIED - Added confirmation mode
+        │   └── Sidebar.jsx      🔄 MODIFIED - User display, Users link
+        │
+        ├── utils/
+        │   └── api.js           🔄 MODIFIED - JWT auth headers
+        │
+        └── App.jsx              🔄 MODIFIED - Auth state, protected routes
+```
+
+---
+
+## Summary
+
+All 5 tasks have been completed successfully:
+
+1. ✅ **Modal Confirmations** - All browser confirm() replaced with beautiful modals
+2. ✅ **Asset Management** - Real file uploads with progress bars working
+3. ✅ **Campaign Deletion** - Cascades to posts and tracks
+4. ✅ **Campaign-Post Links** - Fully functional relationship
+5. ✅ **User Management & Login** - Complete auth system with 3 roles
+
+The application now has a professional authentication system, improved UX with modal confirmations, and fully functional asset management. All existing functionality preserved and enhanced.
+
+**Ready for production use!** 🚀
diff --git a/client/.gitignore b/client/.gitignore
new file mode 100644
index 0000000..a547bf3
--- /dev/null
+++ b/client/.gitignore
@@ -0,0 +1,24 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
diff --git a/client/README.md b/client/README.md
new file mode 100644
index 0000000..18bc70e
--- /dev/null
+++ b/client/README.md
@@ -0,0 +1,16 @@
+# React + Vite
+
+This template provides a minimal setup to get React working in Vite with HMR and some ESLint rules.
+
+Currently, two official plugins are available:
+
+- [@vitejs/plugin-react](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react) uses [Babel](https://babeljs.io/) (or [oxc](https://oxc.rs) when used in [rolldown-vite](https://vite.dev/guide/rolldown)) for Fast Refresh
+- [@vitejs/plugin-react-swc](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react-swc) uses [SWC](https://swc.rs/) for Fast Refresh
+
+## React Compiler
+
+The React Compiler is not enabled on this template because of its impact on dev & build performances. To add it, see [this documentation](https://react.dev/learn/react-compiler/installation).
+
+## Expanding the ESLint configuration
+
+If you are developing a production application, we recommend using TypeScript with type-aware lint rules enabled. Check out the [TS template](https://github.com/vitejs/vite/tree/main/packages/create-vite/template-react-ts) for information on how to integrate TypeScript and [`typescript-eslint`](https://typescript-eslint.io) in your project.
diff --git a/client/eslint.config.js b/client/eslint.config.js
new file mode 100644
index 0000000..4fa125d
--- /dev/null
+++ b/client/eslint.config.js
@@ -0,0 +1,29 @@
+import js from '@eslint/js'
+import globals from 'globals'
+import reactHooks from 'eslint-plugin-react-hooks'
+import reactRefresh from 'eslint-plugin-react-refresh'
+import { defineConfig, globalIgnores } from 'eslint/config'
+
+export default defineConfig([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{js,jsx}'],
+    extends: [
+      js.configs.recommended,
+      reactHooks.configs.flat.recommended,
+      reactRefresh.configs.vite,
+    ],
+    languageOptions: {
+      ecmaVersion: 2020,
+      globals: globals.browser,
+      parserOptions: {
+        ecmaVersion: 'latest',
+        ecmaFeatures: { jsx: true },
+        sourceType: 'module',
+      },
+    },
+    rules: {
+      'no-unused-vars': ['error', { varsIgnorePattern: '^[A-Z_]' }],
+    },
+  },
+])
diff --git a/client/index.html b/client/index.html
new file mode 100644
index 0000000..e01d176
--- /dev/null
+++ b/client/index.html
@@ -0,0 +1,16 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/vite.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <link rel="preconnect" href="https://fonts.googleapis.com">
+    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
+    <link href="https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=IBM+Plex+Sans+Arabic:wght@300;400;500;600;700&display=swap" rel="stylesheet">
+    <title>Samaya Marketing Hub</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.jsx"></script>
+  </body>
+</html>
diff --git a/client/package-lock.json b/client/package-lock.json
new file mode 100644
index 0000000..b398ee0
--- /dev/null
+++ b/client/package-lock.json
@@ -0,0 +1,3501 @@
+{
+  "name": "client",
+  "version": "0.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "client",
+      "version": "0.0.0",
+      "dependencies": {
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+        "date-fns": "^4.1.0",
+        "lucide-react": "^0.563.0",
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+        "react-dom": "^19.2.0",
+        "react-router-dom": "^7.13.0",
+        "tailwindcss": "^4.1.18"
+      },
+      "devDependencies": {
+        "@eslint/js": "^9.39.1",
+        "@types/react": "^19.2.5",
+        "@types/react-dom": "^19.2.3",
+        "@vitejs/plugin-react": "^5.1.1",
+        "eslint": "^9.39.1",
+        "eslint-plugin-react-hooks": "^7.0.1",
+        "eslint-plugin-react-refresh": "^0.4.24",
+        "globals": "^16.5.0",
+        "vite": "^7.2.4"
+      }
+    },
+    "node_modules/@babel/code-frame": {
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diff --git a/client/package.json b/client/package.json
new file mode 100644
index 0000000..ce3999a
--- /dev/null
+++ b/client/package.json
@@ -0,0 +1,32 @@
+{
+  "name": "client",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "lint": "eslint .",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@tailwindcss/vite": "^4.1.18",
+    "date-fns": "^4.1.0",
+    "lucide-react": "^0.563.0",
+    "react": "^19.2.0",
+    "react-dom": "^19.2.0",
+    "react-router-dom": "^7.13.0",
+    "tailwindcss": "^4.1.18"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.39.1",
+    "@types/react": "^19.2.5",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^5.1.1",
+    "eslint": "^9.39.1",
+    "eslint-plugin-react-hooks": "^7.0.1",
+    "eslint-plugin-react-refresh": "^0.4.24",
+    "globals": "^16.5.0",
+    "vite": "^7.2.4"
+  }
+}
diff --git a/client/public/vite.svg b/client/public/vite.svg
new file mode 100644
index 0000000..e7b8dfb
--- /dev/null
+++ b/client/public/vite.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" class="iconify iconify--logos" width="31.88" height="32" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 257"><defs><linearGradient id="IconifyId1813088fe1fbc01fb466" x1="-.828%" x2="57.636%" y1="7.652%" y2="78.411%"><stop offset="0%" stop-color="#41D1FF"></stop><stop offset="100%" stop-color="#BD34FE"></stop></linearGradient><linearGradient id="IconifyId1813088fe1fbc01fb467" x1="43.376%" x2="50.316%" y1="2.242%" y2="89.03%"><stop offset="0%" stop-color="#FFEA83"></stop><stop offset="8.333%" stop-color="#FFDD35"></stop><stop offset="100%" stop-color="#FFA800"></stop></linearGradient></defs><path fill="url(#IconifyId1813088fe1fbc01fb466)" d="M255.153 37.938L134.897 252.976c-2.483 4.44-8.862 4.466-11.382.048L.875 37.958c-2.746-4.814 1.371-10.646 6.827-9.67l120.385 21.517a6.537 6.537 0 0 0 2.322-.004l117.867-21.483c5.438-.991 9.574 4.796 6.877 9.62Z"></path><path fill="url(#IconifyId1813088fe1fbc01fb467)" d="M185.432.063L96.44 17.501a3.268 3.268 0 0 0-2.634 3.014l-5.474 92.456a3.268 3.268 0 0 0 3.997 3.378l24.777-5.718c2.318-.535 4.413 1.507 3.936 3.838l-7.361 36.047c-.495 2.426 1.782 4.5 4.151 3.78l15.304-4.649c2.372-.72 4.652 1.36 4.15 3.788l-11.698 56.621c-.732 3.542 3.979 5.473 5.943 2.437l1.313-2.028l72.516-144.72c1.215-2.423-.88-5.186-3.54-4.672l-25.505 4.922c-2.396.462-4.435-1.77-3.759-4.114l16.646-57.705c.677-2.35-1.37-4.583-3.769-4.113Z"></path></svg>
\ No newline at end of file
diff --git a/client/src/App.jsx b/client/src/App.jsx
new file mode 100644
index 0000000..ea170b7
--- /dev/null
+++ b/client/src/App.jsx
@@ -0,0 +1,175 @@
+import { Routes, Route, Navigate } from 'react-router-dom'
+import { useState, useEffect, createContext } from 'react'
+import { AuthProvider, useAuth } from './contexts/AuthContext'
+import { LanguageProvider } from './i18n/LanguageContext'
+import Layout from './components/Layout'
+import Dashboard from './pages/Dashboard'
+import PostProduction from './pages/PostProduction'
+import Assets from './pages/Assets'
+import Campaigns from './pages/Campaigns'
+import CampaignDetail from './pages/CampaignDetail'
+import Finance from './pages/Finance'
+import Projects from './pages/Projects'
+import ProjectDetail from './pages/ProjectDetail'
+import Tasks from './pages/Tasks'
+import Team from './pages/Team'
+import Users from './pages/Users'
+import Settings from './pages/Settings'
+import Login from './pages/Login'
+import Tutorial from './components/Tutorial'
+import { api } from './utils/api'
+import { useLanguage } from './i18n/LanguageContext'
+
+export const AppContext = createContext()
+
+function AppContent() {
+  const { user, loading: authLoading } = useAuth()
+  const { t } = useLanguage()
+  const [teamMembers, setTeamMembers] = useState([])
+  const [brands, setBrands] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [showTutorial, setShowTutorial] = useState(false)
+  const [showProfilePrompt, setShowProfilePrompt] = useState(false)
+
+  useEffect(() => {
+    if (user && !authLoading) {
+      loadInitialData()
+      // Check if tutorial should be shown
+      if (user.tutorial_completed === 0) {
+        setShowTutorial(true)
+      }
+      // Check if profile is incomplete
+      if (!user.profileComplete && user.role !== 'superadmin') {
+        setShowProfilePrompt(true)
+      }
+    } else if (!authLoading) {
+      setLoading(false)
+    }
+  }, [user, authLoading])
+
+  const loadTeam = async () => {
+    try {
+      const data = await api.get('/users/team')
+      const members = Array.isArray(data) ? data : (data.data || [])
+      setTeamMembers(members)
+      return members
+    } catch (err) {
+      console.error('Failed to load team:', err)
+      return []
+    }
+  }
+
+  const loadInitialData = async () => {
+    try {
+      const [members, brandsData] = await Promise.all([
+        loadTeam(),
+        api.get('/brands').then(d => Array.isArray(d) ? d : (d.data || [])).catch(() => []),
+      ])
+      setTeamMembers(members)
+      setBrands(brandsData)
+    } catch (err) {
+      console.error('Failed to load initial data:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleTutorialComplete = async () => {
+    try {
+      await api.patch('/users/me/tutorial', { completed: true })
+      setShowTutorial(false)
+    } catch (err) {
+      console.error('Failed to complete tutorial:', err)
+    }
+  }
+
+  if (authLoading || loading) {
+    return (
+      <div className="min-h-screen flex items-center justify-center bg-surface-secondary">
+        <div className="text-center">
+          <div className="w-12 h-12 border-4 border-brand-primary border-t-transparent rounded-full animate-spin mx-auto mb-4"></div>
+          <p className="text-text-secondary font-medium">{t('dashboard.loadingHub')}</p>
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <AppContext.Provider value={{ currentUser: user, teamMembers, brands, loadTeam }}>
+      {/* Profile completion prompt */}
+      {showProfilePrompt && (
+        <div className="fixed top-4 right-4 z-50 bg-amber-50 border-2 border-amber-400 rounded-xl shadow-lg p-4 max-w-md animate-fade-in">
+          <div className="flex items-start gap-3">
+            <div className="w-10 h-10 rounded-full bg-amber-400 flex items-center justify-center text-white shrink-0">
+              ⚠️
+            </div>
+            <div className="flex-1">
+              <h3 className="font-semibold text-amber-900 mb-1">{t('profile.completeYourProfile')}</h3>
+              <p className="text-sm text-amber-800 mb-3">
+                {t('profile.completeDesc')}
+              </p>
+              <div className="flex gap-2">
+                <a
+                  href="/team"
+                  className="px-3 py-1.5 bg-amber-400 text-white text-sm font-medium rounded-lg hover:bg-amber-500 transition-colors"
+                >
+                  {t('profile.completeProfileBtn')}
+                </a>
+                <button
+                  onClick={() => setShowProfilePrompt(false)}
+                  className="px-3 py-1.5 text-sm font-medium text-amber-800 hover:bg-amber-100 rounded-lg transition-colors"
+                >
+                  {t('profile.later')}
+                </button>
+              </div>
+            </div>
+            <button
+              onClick={() => setShowProfilePrompt(false)}
+              className="text-amber-600 hover:text-amber-800 transition-colors"
+            >
+              ✕
+            </button>
+          </div>
+        </div>
+      )}
+
+      {/* Tutorial overlay */}
+      {showTutorial && <Tutorial onComplete={handleTutorialComplete} />}
+
+      <Routes>
+        <Route path="/login" element={user ? <Navigate to="/" replace /> : <Login />} />
+        <Route path="/" element={user ? <Layout /> : <Navigate to="/login" replace />}>
+          <Route index element={<Dashboard />} />
+          <Route path="posts" element={<PostProduction />} />
+          <Route path="assets" element={<Assets />} />
+          <Route path="campaigns" element={<Campaigns />} />
+          <Route path="campaigns/:id" element={<CampaignDetail />} />
+          {(user?.role === 'superadmin' || user?.role === 'manager') && (
+            <Route path="finance" element={<Finance />} />
+          )}
+          <Route path="projects" element={<Projects />} />
+          <Route path="projects/:id" element={<ProjectDetail />} />
+          <Route path="tasks" element={<Tasks />} />
+          <Route path="team" element={<Team />} />
+          <Route path="settings" element={<Settings />} />
+          {user?.role === 'superadmin' && (
+            <Route path="users" element={<Users />} />
+          )}
+        </Route>
+        <Route path="*" element={<Navigate to="/" replace />} />
+      </Routes>
+    </AppContext.Provider>
+  )
+}
+
+function App() {
+  return (
+    <LanguageProvider>
+      <AuthProvider>
+        <AppContent />
+      </AuthProvider>
+    </LanguageProvider>
+  )
+}
+
+export default App
diff --git a/client/src/components/AssetCard.jsx b/client/src/components/AssetCard.jsx
new file mode 100644
index 0000000..2e0c28f
--- /dev/null
+++ b/client/src/components/AssetCard.jsx
@@ -0,0 +1,86 @@
+import { format } from 'date-fns'
+import { Image, FileText, Film, Music, File, Download } from 'lucide-react'
+
+const typeIcons = {
+  image: Image,
+  document: FileText,
+  video: Film,
+  audio: Music,
+}
+
+const formatFileSize = (bytes) => {
+  if (!bytes) return '—'
+  if (bytes < 1024) return `${bytes} B`
+  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`
+  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`
+}
+
+export default function AssetCard({ asset, onClick }) {
+  const TypeIcon = typeIcons[asset.type] || File
+  const isImage = asset.type === 'image'
+
+  return (
+    <div
+      onClick={() => onClick?.(asset)}
+      className="bg-white rounded-xl border border-border overflow-hidden card-hover cursor-pointer group"
+    >
+      {/* Thumbnail */}
+      <div className="aspect-square bg-surface-tertiary flex items-center justify-center overflow-hidden relative">
+        {isImage && asset.url ? (
+          <img
+            src={asset.url}
+            alt={asset.name}
+            className="w-full h-full object-cover group-hover:scale-105 transition-transform duration-300"
+            onError={(e) => {
+              e.target.style.display = 'none'
+              e.target.nextSibling.style.display = 'flex'
+            }}
+          />
+        ) : null}
+        <div
+          className={`flex flex-col items-center justify-center gap-2 ${isImage && asset.url ? 'hidden' : ''}`}
+          style={{ display: isImage && asset.url ? 'none' : 'flex' }}
+        >
+          <TypeIcon className="w-10 h-10 text-text-tertiary" />
+          <span className="text-xs text-text-tertiary uppercase font-medium">
+            {asset.fileType || asset.type}
+          </span>
+        </div>
+        
+        {/* Hover overlay */}
+        <div className="absolute inset-0 bg-black/0 group-hover:bg-black/10 transition-colors flex items-center justify-center">
+          <button className="opacity-0 group-hover:opacity-100 bg-white/90 backdrop-blur-sm rounded-full p-2 shadow-lg transition-opacity">
+            <Download className="w-4 h-4 text-text-primary" />
+          </button>
+        </div>
+      </div>
+
+      {/* Info */}
+      <div className="p-3">
+        <h5 className="text-sm font-medium text-text-primary truncate">{asset.name}</h5>
+        <div className="flex items-center justify-between mt-1.5">
+          <span className="text-xs text-text-tertiary">{formatFileSize(asset.size)}</span>
+          {asset.createdAt && (
+            <span className="text-xs text-text-tertiary">
+              {format(new Date(asset.createdAt), 'MMM d')}
+            </span>
+          )}
+        </div>
+        {asset.tags && asset.tags.length > 0 && (
+          <div className="flex flex-wrap gap-1 mt-2">
+            {asset.tags.slice(0, 3).map((tag) => (
+              <span key={tag} className="text-[10px] px-1.5 py-0.5 rounded bg-surface-tertiary text-text-tertiary">
+                {tag}
+              </span>
+            ))}
+            {asset.tags.length > 3 && (
+              <span className="text-[10px] px-1.5 py-0.5 text-text-tertiary">
+                +{asset.tags.length - 3}
+              </span>
+            )}
+          </div>
+        )}
+      </div>
+    </div>
+  )
+}
diff --git a/client/src/components/BrandBadge.jsx b/client/src/components/BrandBadge.jsx
new file mode 100644
index 0000000..4b362d5
--- /dev/null
+++ b/client/src/components/BrandBadge.jsx
@@ -0,0 +1,12 @@
+import { getBrandColor } from '../utils/api'
+
+export default function BrandBadge({ brand }) {
+  const color = getBrandColor(brand)
+  
+  return (
+    <span className={`inline-flex items-center gap-1.5 text-xs font-medium px-2 py-0.5 rounded-full ${color.bg} ${color.text}`}>
+      <span className={`w-1.5 h-1.5 rounded-full ${color.dot}`}></span>
+      {brand}
+    </span>
+  )
+}
diff --git a/client/src/components/CampaignCalendar.jsx b/client/src/components/CampaignCalendar.jsx
new file mode 100644
index 0000000..69c157f
--- /dev/null
+++ b/client/src/components/CampaignCalendar.jsx
@@ -0,0 +1,132 @@
+import { useState, useMemo } from 'react'
+import {
+  startOfMonth, endOfMonth, startOfWeek, endOfWeek,
+  eachDayOfInterval, format, isSameMonth, isToday,
+  addMonths, subMonths, isBefore, isAfter, isSameDay
+} from 'date-fns'
+import { ChevronLeft, ChevronRight } from 'lucide-react'
+import { getBrandColor } from '../utils/api'
+
+const CAMPAIGN_COLORS = [
+  'bg-indigo-400', 'bg-pink-400', 'bg-emerald-400', 'bg-amber-400',
+  'bg-purple-400', 'bg-cyan-400', 'bg-rose-400', 'bg-teal-400',
+]
+
+export default function CampaignCalendar({ campaigns = [] }) {
+  const [currentMonth, setCurrentMonth] = useState(new Date())
+
+  const days = useMemo(() => {
+    const monthStart = startOfMonth(currentMonth)
+    const monthEnd = endOfMonth(currentMonth)
+    const calStart = startOfWeek(monthStart, { weekStartsOn: 0 })
+    const calEnd = endOfWeek(monthEnd, { weekStartsOn: 0 })
+    return eachDayOfInterval({ start: calStart, end: calEnd })
+  }, [currentMonth])
+
+  const getCampaignsForDay = (day) => {
+    return campaigns.filter((c) => {
+      const start = new Date(c.startDate)
+      const end = new Date(c.endDate)
+      return (isSameDay(day, start) || isAfter(day, start)) && 
+             (isSameDay(day, end) || isBefore(day, end))
+    })
+  }
+
+  const isStartOfCampaign = (day, campaign) => {
+    return isSameDay(day, new Date(campaign.startDate))
+  }
+
+  const isEndOfCampaign = (day, campaign) => {
+    return isSameDay(day, new Date(campaign.endDate))
+  }
+
+  return (
+    <div className="bg-white rounded-xl border border-border overflow-hidden">
+      {/* Header */}
+      <div className="flex items-center justify-between px-6 py-4 border-b border-border">
+        <h3 className="text-lg font-semibold text-text-primary">
+          {format(currentMonth, 'MMMM yyyy')}
+        </h3>
+        <div className="flex items-center gap-2">
+          <button
+            onClick={() => setCurrentMonth(subMonths(currentMonth, 1))}
+            className="p-1.5 rounded-lg hover:bg-surface-tertiary text-text-secondary"
+          >
+            <ChevronLeft className="w-5 h-5" />
+          </button>
+          <button
+            onClick={() => setCurrentMonth(new Date())}
+            className="px-3 py-1 text-sm font-medium rounded-lg hover:bg-surface-tertiary text-text-secondary"
+          >
+            Today
+          </button>
+          <button
+            onClick={() => setCurrentMonth(addMonths(currentMonth, 1))}
+            className="p-1.5 rounded-lg hover:bg-surface-tertiary text-text-secondary"
+          >
+            <ChevronRight className="w-5 h-5" />
+          </button>
+        </div>
+      </div>
+
+      {/* Day names */}
+      <div className="calendar-grid border-b border-border">
+        {['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'].map((d) => (
+          <div key={d} className="px-2 py-2 text-center text-xs font-semibold text-text-tertiary uppercase tracking-wider">
+            {d}
+          </div>
+        ))}
+      </div>
+
+      {/* Calendar grid */}
+      <div className="calendar-grid">
+        {days.map((day, i) => {
+          const dayCampaigns = getCampaignsForDay(day)
+          const inMonth = isSameMonth(day, currentMonth)
+          const today = isToday(day)
+
+          return (
+            <div
+              key={i}
+              className={`min-h-[80px] p-1 border-b border-r border-border-light relative ${
+                !inMonth ? 'bg-surface-secondary/50' : ''
+              }`}
+            >
+              <span className={`text-xs font-medium inline-flex items-center justify-center w-6 h-6 rounded-full ${
+                today ? 'bg-brand-primary text-white' : 
+                inMonth ? 'text-text-primary' : 'text-text-tertiary'
+              }`}>
+                {format(day, 'd')}
+              </span>
+              
+              <div className="space-y-0.5 mt-0.5">
+                {dayCampaigns.slice(0, 3).map((campaign, ci) => {
+                  const colorIndex = campaigns.indexOf(campaign) % CAMPAIGN_COLORS.length
+                  const isStart = isStartOfCampaign(day, campaign)
+                  const isEnd = isEndOfCampaign(day, campaign)
+
+                  return (
+                    <div
+                      key={campaign._id || ci}
+                      className={`h-5 text-[10px] font-medium text-white flex items-center px-1 truncate ${CAMPAIGN_COLORS[colorIndex]} ${
+                        isStart ? 'rounded-l-full ml-0' : '-ml-1'
+                      } ${isEnd ? 'rounded-r-full mr-0' : '-mr-1'}`}
+                      title={campaign.name}
+                    >
+                      {isStart ? campaign.name : ''}
+                    </div>
+                  )
+                })}
+                {dayCampaigns.length > 3 && (
+                  <div className="text-[10px] text-text-tertiary px-1">
+                    +{dayCampaigns.length - 3} more
+                  </div>
+                )}
+              </div>
+            </div>
+          )
+        })}
+      </div>
+    </div>
+  )
+}
diff --git a/client/src/components/Header.jsx b/client/src/components/Header.jsx
new file mode 100644
index 0000000..9f8f61f
--- /dev/null
+++ b/client/src/components/Header.jsx
@@ -0,0 +1,134 @@
+import { useState, useRef, useEffect } from 'react'
+import { useLocation } from 'react-router-dom'
+import { Bell, ChevronDown, LogOut, Settings, User, Shield } from 'lucide-react'
+import { useAuth } from '../contexts/AuthContext'
+
+const pageTitles = {
+  '/': 'Dashboard',
+  '/posts': 'Post Production',
+  '/assets': 'Assets',
+  '/campaigns': 'Campaigns',
+  '/finance': 'Finance',
+  '/projects': 'Projects',
+  '/tasks': 'My Tasks',
+  '/team': 'Team',
+  '/users': 'User Management',
+}
+
+const ROLE_INFO = {
+  superadmin: { label: 'Superadmin', color: 'bg-purple-100 text-purple-700', icon: '👑' },
+  manager: { label: 'Manager', color: 'bg-blue-100 text-blue-700', icon: '📊' },
+  contributor: { label: 'Contributor', color: 'bg-green-100 text-green-700', icon: '✏️' },
+}
+
+export default function Header() {
+  const { user, logout } = useAuth()
+  const [showDropdown, setShowDropdown] = useState(false)
+  const dropdownRef = useRef(null)
+  const location = useLocation()
+
+  const pageTitle = pageTitles[location.pathname] || 
+    (location.pathname.startsWith('/projects/') ? 'Project Details' : 
+     location.pathname.startsWith('/campaigns/') ? 'Campaign Details' : 'Page')
+
+  useEffect(() => {
+    const handleClickOutside = (e) => {
+      if (dropdownRef.current && !dropdownRef.current.contains(e.target)) {
+        setShowDropdown(false)
+      }
+    }
+    document.addEventListener('mousedown', handleClickOutside)
+    return () => document.removeEventListener('mousedown', handleClickOutside)
+  }, [])
+
+  const getInitials = (name) => {
+    if (!name) return '?'
+    return name.split(' ').map(w => w[0]).join('').slice(0, 2).toUpperCase()
+  }
+
+  const roleInfo = ROLE_INFO[user?.role] || ROLE_INFO.contributor
+
+  return (
+    <header className="h-16 bg-white border-b border-border flex items-center justify-between px-6 shrink-0 sticky top-0 z-20">
+      {/* Page title */}
+      <div>
+        <h2 className="text-xl font-bold text-text-primary">{pageTitle}</h2>
+      </div>
+
+      {/* Right side */}
+      <div className="flex items-center gap-4">
+        {/* Notifications */}
+        <button className="relative p-2 rounded-lg hover:bg-surface-tertiary text-text-secondary hover:text-text-primary transition-colors">
+          <Bell className="w-5 h-5" />
+          <span className="absolute top-1.5 right-1.5 w-2 h-2 bg-red-500 rounded-full"></span>
+        </button>
+
+        {/* User menu */}
+        <div ref={dropdownRef} className="relative">
+          <button
+            onClick={() => setShowDropdown(!showDropdown)}
+            className="flex items-center gap-3 px-3 py-2 rounded-lg hover:bg-surface-tertiary transition-colors"
+          >
+            <div className={`w-8 h-8 rounded-full flex items-center justify-center text-white text-xs font-semibold ${
+              user?.role === 'superadmin' 
+                ? 'bg-gradient-to-br from-purple-500 to-pink-500' 
+                : 'bg-gradient-to-br from-blue-500 to-indigo-500'
+            }`}>
+              {getInitials(user?.name)}
+            </div>
+            <div className="text-left hidden sm:block">
+              <p className="text-sm font-medium text-text-primary">
+                {user?.name || 'User'}
+              </p>
+              <p className={`text-[10px] font-medium ${roleInfo.color.split(' ')[1]}`}>
+                {roleInfo.icon} {roleInfo.label}
+              </p>
+            </div>
+            <ChevronDown className={`w-4 h-4 text-text-tertiary transition-transform ${showDropdown ? 'rotate-180' : ''}`} />
+          </button>
+
+          {showDropdown && (
+            <div className="absolute right-0 top-full mt-2 w-64 bg-white rounded-xl shadow-lg border border-border overflow-hidden animate-scale-in">
+              {/* User info */}
+              <div className="px-4 py-3 border-b border-border-light bg-surface-secondary">
+                <p className="text-sm font-semibold text-text-primary">{user?.name}</p>
+                <p className="text-xs text-text-tertiary">{user?.email}</p>
+                <div className={`inline-flex items-center gap-1 text-[10px] font-medium px-2 py-0.5 rounded-full mt-2 ${roleInfo.color}`}>
+                  <span>{roleInfo.icon}</span>
+                  {roleInfo.label}
+                </div>
+              </div>
+
+              {/* Menu items */}
+              <div className="py-2">
+                {user?.role === 'superadmin' && (
+                  <button
+                    onClick={() => { 
+                      setShowDropdown(false)
+                      window.location.href = '/users'
+                    }}
+                    className="w-full flex items-center gap-3 px-4 py-2.5 hover:bg-surface-secondary transition-colors text-left"
+                  >
+                    <Shield className="w-4 h-4 text-text-tertiary" />
+                    <span className="text-sm text-text-primary">User Management</span>
+                  </button>
+                )}
+                
+                <button
+                  onClick={() => { 
+                    setShowDropdown(false)
+                    logout()
+                  }}
+                  className="w-full flex items-center gap-3 px-4 py-2.5 hover:bg-red-50 transition-colors text-left group"
+                >
+                  <LogOut className="w-4 h-4 text-text-tertiary group-hover:text-red-500" />
+                  <span className="text-sm text-text-primary group-hover:text-red-500">Sign Out</span>
+                </button>
+              </div>
+            </div>
+          )}
+        </div>
+      </div>
+    </header>
+  )
+}
diff --git a/client/src/components/KanbanBoard.jsx b/client/src/components/KanbanBoard.jsx
new file mode 100644
index 0000000..dcaecba
--- /dev/null
+++ b/client/src/components/KanbanBoard.jsx
@@ -0,0 +1,111 @@
+import { useState } from 'react'
+import PostCard from './PostCard'
+import { useLanguage } from '../i18n/LanguageContext'
+
+const COLUMNS = [
+  { id: 'draft', labelKey: 'posts.status.draft', color: 'bg-gray-400' },
+  { id: 'in_review', labelKey: 'posts.status.in_review', color: 'bg-amber-400' },
+  { id: 'approved', labelKey: 'posts.status.approved', color: 'bg-blue-400' },
+  { id: 'scheduled', labelKey: 'posts.status.scheduled', color: 'bg-purple-400' },
+  { id: 'published', labelKey: 'posts.status.published', color: 'bg-emerald-400' },
+]
+
+export default function KanbanBoard({ posts, onPostClick, onMovePost }) {
+  const { t } = useLanguage()
+  const [draggedPost, setDraggedPost] = useState(null)
+  const [dragOverCol, setDragOverCol] = useState(null)
+
+  const handleDragStart = (e, post) => {
+    setDraggedPost(post)
+    e.dataTransfer.effectAllowed = 'move'
+    // Make the drag image slightly transparent
+    if (e.target) {
+      setTimeout(() => e.target.style.opacity = '0.4', 0)
+    }
+  }
+
+  const handleDragEnd = (e) => {
+    e.target.style.opacity = '1'
+    setDraggedPost(null)
+    setDragOverCol(null)
+  }
+
+  const handleDragOver = (e, colId) => {
+    e.preventDefault()
+    e.dataTransfer.dropEffect = 'move'
+    setDragOverCol(colId)
+  }
+
+  const handleDragLeave = (e, colId) => {
+    // Only clear if we're actually leaving the column (not entering a child)
+    if (!e.currentTarget.contains(e.relatedTarget)) {
+      setDragOverCol(null)
+    }
+  }
+
+  const handleDrop = (e, colId) => {
+    e.preventDefault()
+    setDragOverCol(null)
+    if (draggedPost && draggedPost.status !== colId) {
+      onMovePost(draggedPost._id, colId)
+    }
+    setDraggedPost(null)
+  }
+
+  return (
+    <div className="flex gap-4 overflow-x-auto pb-4">
+      {COLUMNS.map((col) => {
+        const colPosts = posts.filter((p) => p.status === col.id)
+        const isOver = dragOverCol === col.id && draggedPost?.status !== col.id
+
+        return (
+          <div key={col.id} className="flex-shrink-0 w-72">
+            {/* Column header */}
+            <div className="flex items-center gap-2 mb-3 px-1">
+              <div className={`w-2.5 h-2.5 rounded-full ${col.color}`} />
+              <h4 className="text-sm font-semibold text-text-primary">{t(col.labelKey)}</h4>
+              <span className="text-xs font-medium text-text-tertiary bg-surface-tertiary px-2 py-0.5 rounded-full ml-auto">
+                {colPosts.length}
+              </span>
+            </div>
+
+            {/* Column body — drop zone */}
+            <div
+              className={`kanban-column rounded-xl p-2 space-y-2 border-2 transition-colors min-h-[120px] ${
+                isOver
+                  ? 'bg-brand-primary/5 border-brand-primary/40 border-dashed'
+                  : 'bg-surface-secondary border-border-light border-solid'
+              }`}
+              onDragOver={(e) => handleDragOver(e, col.id)}
+              onDragLeave={(e) => handleDragLeave(e, col.id)}
+              onDrop={(e) => handleDrop(e, col.id)}
+            >
+              {colPosts.length === 0 ? (
+                <div className={`py-8 text-center text-xs ${isOver ? 'text-brand-primary font-medium' : 'text-text-tertiary'}`}>
+                  {isOver ? t('posts.dropHere') : t('posts.noPosts')}
+                </div>
+              ) : (
+                colPosts.map((post) => (
+                  <div
+                    key={post._id}
+                    draggable
+                    onDragStart={(e) => handleDragStart(e, post)}
+                    onDragEnd={handleDragEnd}
+                    className="cursor-grab active:cursor-grabbing"
+                  >
+                    <PostCard
+                      post={post}
+                      onClick={() => onPostClick(post)}
+                      onMove={onMovePost}
+                      compact
+                    />
+                  </div>
+                ))
+              )}
+            </div>
+          </div>
+        )
+      })}
+    </div>
+  )
+}
diff --git a/client/src/components/Layout.jsx b/client/src/components/Layout.jsx
new file mode 100644
index 0000000..f55f9f8
--- /dev/null
+++ b/client/src/components/Layout.jsx
@@ -0,0 +1,24 @@
+import { useState } from 'react'
+import { Outlet } from 'react-router-dom'
+import Sidebar from './Sidebar'
+import Header from './Header'
+
+export default function Layout() {
+  const [collapsed, setCollapsed] = useState(false)
+
+  return (
+    <div className="min-h-screen bg-surface-secondary">
+      <Sidebar collapsed={collapsed} setCollapsed={setCollapsed} />
+      <div
+        className={`transition-all duration-300 ${
+          collapsed ? 'main-content-margin-collapsed' : 'main-content-margin'
+        }`}
+      >
+        <Header />
+        <main className="p-6">
+          <Outlet />
+        </main>
+      </div>
+    </div>
+  )
+}
diff --git a/client/src/components/MemberCard.jsx b/client/src/components/MemberCard.jsx
new file mode 100644
index 0000000..874b3d4
--- /dev/null
+++ b/client/src/components/MemberCard.jsx
@@ -0,0 +1,68 @@
+import BrandBadge from './BrandBadge'
+
+const ROLE_BADGES = {
+  manager: { bg: 'bg-indigo-50', text: 'text-indigo-700', label: 'Manager' },
+  approver: { bg: 'bg-emerald-50', text: 'text-emerald-700', label: 'Approver' },
+  publisher: { bg: 'bg-blue-50', text: 'text-blue-700', label: 'Publisher' },
+  content_creator: { bg: 'bg-amber-50', text: 'text-amber-700', label: 'Content Creator' },
+  producer: { bg: 'bg-purple-50', text: 'text-purple-700', label: 'Producer' },
+  designer: { bg: 'bg-pink-50', text: 'text-pink-700', label: 'Designer' },
+  content_writer: { bg: 'bg-orange-50', text: 'text-orange-700', label: 'Content Writer' },
+  social_media_manager: { bg: 'bg-teal-50', text: 'text-teal-700', label: 'Social Media Manager' },
+  photographer: { bg: 'bg-cyan-50', text: 'text-cyan-700', label: 'Photographer' },
+  videographer: { bg: 'bg-sky-50', text: 'text-sky-700', label: 'Videographer' },
+  strategist: { bg: 'bg-rose-50', text: 'text-rose-700', label: 'Strategist' },
+  default: { bg: 'bg-gray-50', text: 'text-gray-700', label: 'Team Member' },
+}
+
+export default function MemberCard({ member, onClick }) {
+  const getInitials = (name) => {
+    if (!name) return '?'
+    return name.split(' ').map(w => w[0]).join('').slice(0, 2).toUpperCase()
+  }
+
+  const role = ROLE_BADGES[member.team_role || member.role] || ROLE_BADGES.default
+
+  const avatarColors = [
+    'from-indigo-400 to-purple-500',
+    'from-pink-400 to-rose-500',
+    'from-emerald-400 to-teal-500',
+    'from-amber-400 to-orange-500',
+    'from-cyan-400 to-blue-500',
+  ]
+  const colorIndex = (member.name?.charCodeAt(0) || 0) % avatarColors.length
+
+  return (
+    <div
+      onClick={() => onClick?.(member)}
+      className="bg-white rounded-xl border border-border p-5 card-hover cursor-pointer text-center"
+    >
+      {/* Avatar */}
+      <div className={`w-16 h-16 rounded-full bg-gradient-to-br ${avatarColors[colorIndex]} flex items-center justify-center text-white text-xl font-bold mx-auto mb-3`}>
+        {getInitials(member.name)}
+      </div>
+
+      {/* Name */}
+      <h4 className="text-base font-semibold text-text-primary">{member.name}</h4>
+
+      {/* Role badge */}
+      <span className={`inline-block text-xs font-medium px-2 py-0.5 rounded-full mt-1 ${role.bg} ${role.text}`}>
+        {role.label}
+      </span>
+
+      {/* Email */}
+      {member.email && (
+        <p className="text-xs text-text-tertiary mt-2">{member.email}</p>
+      )}
+
+      {/* Brands */}
+      {member.brands && member.brands.length > 0 && (
+        <div className="flex flex-wrap gap-1 justify-center mt-3 pt-3 border-t border-border-light">
+          {member.brands.map((brand) => (
+            <BrandBadge key={brand} brand={brand} />
+          ))}
+        </div>
+      )}
+    </div>
+  )
+}
diff --git a/client/src/components/Modal.jsx b/client/src/components/Modal.jsx
new file mode 100644
index 0000000..b09382d
--- /dev/null
+++ b/client/src/components/Modal.jsx
@@ -0,0 +1,122 @@
+import { useEffect } from 'react'
+import { createPortal } from 'react-dom'
+import { X, AlertTriangle } from 'lucide-react'
+import { useLanguage } from '../i18n/LanguageContext'
+
+export default function Modal({ 
+  isOpen, 
+  onClose, 
+  title, 
+  children, 
+  size = 'md',
+  // Confirmation mode props
+  isConfirm = false,
+  confirmText,
+  cancelText,
+  onConfirm,
+  danger = false,
+}) {
+  const { t } = useLanguage()
+  
+  // Default translations
+  const finalConfirmText = confirmText || (danger ? t('common.delete') : t('common.save'))
+  const finalCancelText = cancelText || t('common.cancel')
+  useEffect(() => {
+    if (isOpen) {
+      document.body.style.overflow = 'hidden'
+    } else {
+      document.body.style.overflow = ''
+    }
+    return () => { document.body.style.overflow = '' }
+  }, [isOpen])
+
+  if (!isOpen) return null
+
+  const sizeClasses = {
+    sm: 'max-w-md',
+    md: 'max-w-lg',
+    lg: 'max-w-2xl',
+    xl: 'max-w-4xl',
+  }
+
+  // Confirmation dialog
+  if (isConfirm) {
+    return createPortal(
+      <div className="fixed inset-0 z-[9999] flex items-center justify-center px-4">
+        {/* Backdrop */}
+        <div
+          className="fixed inset-0 bg-black/40 backdrop-blur-sm"
+          onClick={onClose}
+        />
+        
+        {/* Modal content */}
+        <div className="relative bg-white rounded-2xl shadow-2xl w-full max-w-md animate-scale-in">
+          <div className="p-6">
+            {danger && (
+              <div className="w-12 h-12 rounded-full bg-red-100 flex items-center justify-center mx-auto mb-4">
+                <AlertTriangle className="w-6 h-6 text-red-600" />
+              </div>
+            )}
+            <h3 className="text-lg font-semibold text-text-primary text-center mb-2">{title}</h3>
+            <div className="text-sm text-text-secondary text-center mb-6">
+              {children}
+            </div>
+            <div className="flex items-center gap-3">
+              <button
+                onClick={onClose}
+                className="flex-1 px-4 py-2.5 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg transition-colors"
+              >
+                {finalCancelText}
+              </button>
+              <button
+                onClick={() => {
+                  onConfirm?.();
+                  onClose();
+                }}
+                className={`flex-1 px-4 py-2.5 text-sm font-medium text-white rounded-lg shadow-sm transition-colors ${
+                  danger 
+                    ? 'bg-red-600 hover:bg-red-700' 
+                    : 'bg-brand-primary hover:bg-brand-primary-light'
+                }`}
+              >
+                {finalConfirmText}
+              </button>
+            </div>
+          </div>
+        </div>
+      </div>,
+      document.body
+    )
+  }
+
+  // Regular modal
+  return createPortal(
+    <div className="fixed inset-0 z-[9999] flex items-start justify-center pt-[10vh] px-4">
+      {/* Backdrop */}
+      <div
+        className="fixed inset-0 bg-black/40 backdrop-blur-sm"
+        onClick={onClose}
+      />
+      
+      {/* Modal content */}
+      <div className={`relative bg-white rounded-2xl shadow-2xl w-full ${sizeClasses[size]} max-h-[80vh] flex flex-col animate-scale-in`}>
+        {/* Header */}
+        <div className="flex items-center justify-between px-6 py-4 border-b border-border shrink-0">
+          <h3 className="text-lg font-semibold text-text-primary">{title}</h3>
+          <button
+            onClick={onClose}
+            className="p-1.5 rounded-lg hover:bg-surface-tertiary text-text-tertiary hover:text-text-primary transition-colors"
+          >
+            <X className="w-5 h-5" />
+          </button>
+        </div>
+        
+        {/* Body */}
+        <div className="px-6 py-4 overflow-y-auto flex-1">
+          {children}
+        </div>
+      </div>
+    </div>,
+    document.body
+  )
+}
diff --git a/client/src/components/PlatformIcon.jsx b/client/src/components/PlatformIcon.jsx
new file mode 100644
index 0000000..201c200
--- /dev/null
+++ b/client/src/components/PlatformIcon.jsx
@@ -0,0 +1,30 @@
+import { PLATFORMS } from '../utils/api'
+
+export default function PlatformIcon({ platform, size = 16, showLabel = false, className = '' }) {
+  const p = PLATFORMS[platform]
+  if (!p) return <span className="text-[10px] text-text-tertiary capitalize">{platform}</span>
+
+  return (
+    <span className={`inline-flex items-center gap-1 ${className}`} title={p.label}>
+      <svg
+        width={size}
+        height={size}
+        viewBox="0 0 24 24"
+        fill={p.color}
+        className="shrink-0"
+      >
+        <path d={p.icon} />
+      </svg>
+      {showLabel && <span className="text-xs text-text-secondary">{p.label}</span>}
+    </span>
+  )
+}
+
+export function PlatformIcons({ platforms = [], size = 14, gap = 'gap-1', className = '' }) {
+  if (!platforms || platforms.length === 0) return null
+  return (
+    <span className={`inline-flex items-center ${gap} ${className}`}>
+      {platforms.map(p => <PlatformIcon key={p} platform={p} size={size} />)}
+    </span>
+  )
+}
diff --git a/client/src/components/PostCard.jsx b/client/src/components/PostCard.jsx
new file mode 100644
index 0000000..370006f
--- /dev/null
+++ b/client/src/components/PostCard.jsx
@@ -0,0 +1,121 @@
+import { format } from 'date-fns'
+import { ArrowRight } from 'lucide-react'
+import { useLanguage } from '../i18n/LanguageContext'
+import BrandBadge from './BrandBadge'
+import StatusBadge from './StatusBadge'
+import PlatformIcon, { PlatformIcons } from './PlatformIcon'
+
+export default function PostCard({ post, onClick, onMove, compact = false }) {
+  const { t } = useLanguage()
+  // Support both single platform and platforms array
+  const platforms = post.platforms?.length > 0
+    ? post.platforms
+    : (post.platform ? [post.platform] : [])
+
+  const getInitials = (name) => {
+    if (!name) return '?'
+    return name.split(' ').map(w => w[0]).join('').slice(0, 2).toUpperCase()
+  }
+
+  const assigneeName = post.assignedToName || post.assignedName || post.assigned_name || (typeof post.assignedTo === 'object' ? post.assignedTo?.name : null)
+
+  if (compact) {
+    return (
+      <div
+        onClick={onClick}
+        className="bg-white rounded-lg p-3 border border-border hover:border-brand-primary/30 hover:shadow-md cursor-pointer transition-all group"
+      >
+        {post.thumbnail_url && (
+          <div className="w-full h-32 -mx-3 -mt-3 mb-2 rounded-t-lg overflow-hidden">
+            <img src={`http://localhost:3001${post.thumbnail_url}`} alt="" className="w-full h-full object-cover" />
+          </div>
+        )}
+        
+        <div className="flex items-start justify-between gap-2 mb-2">
+          <h5 className="text-sm font-medium text-text-primary line-clamp-2 leading-snug">{post.title}</h5>
+          <div className="shrink-0 mt-0.5">
+            <PlatformIcons platforms={platforms} size={14} />
+          </div>
+        </div>
+        
+        <div className="flex items-center gap-2 flex-wrap">
+          {post.brand && <BrandBadge brand={post.brand} />}
+        </div>
+
+        <div className="flex items-center justify-between mt-3 pt-2 border-t border-border-light">
+          {assigneeName ? (
+            <div className="flex items-center gap-1.5">
+              <div className="w-5 h-5 rounded-full bg-brand-primary/10 text-brand-primary flex items-center justify-center text-[10px] font-semibold">
+                {getInitials(assigneeName)}
+              </div>
+              <span className="text-xs text-text-tertiary">{assigneeName}</span>
+            </div>
+          ) : (
+            <span className="text-xs text-text-tertiary">{t('common.unassigned')}</span>
+          )}
+          
+          {post.scheduledDate && (
+            <span className="text-[10px] text-text-tertiary">
+              {format(new Date(post.scheduledDate), 'MMM d')}
+            </span>
+          )}
+        </div>
+
+        {/* Quick move buttons */}
+        {onMove && (
+          <div className="hidden group-hover:flex items-center gap-1 mt-2 pt-2 border-t border-border-light">
+            {post.status === 'draft' && (
+              <button onClick={(e) => { e.stopPropagation(); onMove(post._id, 'in_review') }}
+                className="text-[10px] text-amber-600 hover:bg-amber-50 px-2 py-0.5 rounded-full flex items-center gap-1">
+                {t('posts.sendToReview')} <ArrowRight className="w-3 h-3" />
+              </button>
+            )}
+            {post.status === 'in_review' && (
+              <button onClick={(e) => { e.stopPropagation(); onMove(post._id, 'approved') }}
+                className="text-[10px] text-blue-600 hover:bg-blue-50 px-2 py-0.5 rounded-full flex items-center gap-1">
+                {t('posts.approve')} <ArrowRight className="w-3 h-3" />
+              </button>
+            )}
+            {post.status === 'approved' && (
+              <button onClick={(e) => { e.stopPropagation(); onMove(post._id, 'scheduled') }}
+                className="text-[10px] text-purple-600 hover:bg-purple-50 px-2 py-0.5 rounded-full flex items-center gap-1">
+                {t('posts.schedule')} <ArrowRight className="w-3 h-3" />
+              </button>
+            )}
+            {post.status === 'scheduled' && (
+              <button onClick={(e) => { e.stopPropagation(); onMove(post._id, 'published') }}
+                className="text-[10px] text-emerald-600 hover:bg-emerald-50 px-2 py-0.5 rounded-full flex items-center gap-1">
+                {t('posts.publish')} <ArrowRight className="w-3 h-3" />
+              </button>
+            )}
+          </div>
+        )}
+      </div>
+    )
+  }
+
+  // Table row view
+  return (
+    <tr onClick={onClick} className="hover:bg-surface-secondary cursor-pointer group">
+      <td className="px-4 py-3">
+        <div className="flex items-center gap-3">
+          <div className="shrink-0">
+            <PlatformIcons platforms={platforms} size={16} />
+          </div>
+          <span className="text-sm font-medium text-text-primary">{post.title}</span>
+        </div>
+      </td>
+      <td className="px-4 py-3">{post.brand && <BrandBadge brand={post.brand} />}</td>
+      <td className="px-4 py-3"><StatusBadge status={post.status} /></td>
+      <td className="px-4 py-3">
+        <PlatformIcons platforms={platforms} size={16} gap="gap-1.5" />
+      </td>
+      <td className="px-4 py-3">
+        <span className="text-sm text-text-secondary">{assigneeName || '—'}</span>
+      </td>
+      <td className="px-4 py-3 text-sm text-text-tertiary">
+        {post.scheduledDate ? format(new Date(post.scheduledDate), 'MMM d, yyyy') : '—'}
+      </td>
+    </tr>
+  )
+}
diff --git a/client/src/components/ProjectCard.jsx b/client/src/components/ProjectCard.jsx
new file mode 100644
index 0000000..6bc3862
--- /dev/null
+++ b/client/src/components/ProjectCard.jsx
@@ -0,0 +1,68 @@
+import { format } from 'date-fns'
+import { useNavigate } from 'react-router-dom'
+import StatusBadge from './StatusBadge'
+import BrandBadge from './BrandBadge'
+
+export default function ProjectCard({ project }) {
+  const navigate = useNavigate()
+
+  const completedTasks = project.tasks?.filter(t => t.status === 'done').length || 0
+  const totalTasks = project.tasks?.length || 0
+  const progress = totalTasks > 0 ? Math.round((completedTasks / totalTasks) * 100) : 0
+
+  const ownerName = typeof project.owner === 'object' ? project.owner?.name : project.owner
+
+  return (
+    <div
+      onClick={() => navigate(`/projects/${project._id}`)}
+      className="bg-white rounded-xl border border-border p-5 card-hover cursor-pointer"
+    >
+      <div className="flex items-start justify-between gap-3 mb-3">
+        <h4 className="text-base font-semibold text-text-primary line-clamp-1">{project.name}</h4>
+        <StatusBadge status={project.status} size="xs" />
+      </div>
+
+      {project.brand && (
+        <div className="mb-3">
+          <BrandBadge brand={project.brand} />
+        </div>
+      )}
+
+      {project.description && (
+        <p className="text-sm text-text-secondary line-clamp-2 mb-4">{project.description}</p>
+      )}
+
+      {/* Progress bar */}
+      <div className="mb-3">
+        <div className="flex items-center justify-between text-xs mb-1">
+          <span className="text-text-tertiary">Progress</span>
+          <span className="font-medium text-text-secondary">{progress}%</span>
+        </div>
+        <div className="h-1.5 bg-surface-tertiary rounded-full overflow-hidden">
+          <div
+            className="h-full bg-brand-primary rounded-full transition-all duration-500"
+            style={{ width: `${progress}%` }}
+          />
+        </div>
+        <p className="text-[10px] text-text-tertiary mt-1">{completedTasks}/{totalTasks} tasks</p>
+      </div>
+
+      {/* Footer */}
+      <div className="flex items-center justify-between pt-3 border-t border-border-light">
+        {ownerName && (
+          <div className="flex items-center gap-1.5">
+            <div className="w-5 h-5 rounded-full bg-brand-primary/10 text-brand-primary flex items-center justify-center text-[10px] font-semibold">
+              {ownerName.split(' ').map(w => w[0]).join('').slice(0, 2).toUpperCase()}
+            </div>
+            <span className="text-xs text-text-tertiary">{ownerName}</span>
+          </div>
+        )}
+        {project.dueDate && (
+          <span className="text-xs text-text-tertiary">
+            Due {format(new Date(project.dueDate), 'MMM d')}
+          </span>
+        )}
+      </div>
+    </div>
+  )
+}
diff --git a/client/src/components/Sidebar.jsx b/client/src/components/Sidebar.jsx
new file mode 100644
index 0000000..3225993
--- /dev/null
+++ b/client/src/components/Sidebar.jsx
@@ -0,0 +1,169 @@
+import { useContext } from 'react'
+import { NavLink } from 'react-router-dom'
+import {
+  LayoutDashboard, FileEdit, Image, Calendar, Wallet,
+  FolderKanban, CheckSquare, Users, ChevronLeft, ChevronRight, Sparkles, Shield, LogOut, User, Settings, Languages
+} from 'lucide-react'
+import { useAuth } from '../contexts/AuthContext'
+import { useLanguage } from '../i18n/LanguageContext'
+
+const navItems = [
+  { to: '/', icon: LayoutDashboard, labelKey: 'nav.dashboard', end: true, tutorial: 'dashboard' },
+  { to: '/campaigns', icon: Calendar, labelKey: 'nav.campaigns', tutorial: 'campaigns' },
+  { to: '/finance', icon: Wallet, labelKey: 'nav.finance', minRole: 'manager' },
+  { to: '/posts', icon: FileEdit, labelKey: 'nav.posts', tutorial: 'posts' },
+  { to: '/assets', icon: Image, labelKey: 'nav.assets', tutorial: 'assets' },
+  { to: '/projects', icon: FolderKanban, labelKey: 'nav.projects' },
+  { to: '/tasks', icon: CheckSquare, labelKey: 'nav.tasks', tutorial: 'tasks' },
+  { to: '/team', icon: Users, labelKey: 'nav.team', tutorial: 'team' },
+]
+
+const ROLE_LEVEL = { contributor: 0, manager: 1, superadmin: 2 }
+
+export default function Sidebar({ collapsed, setCollapsed }) {
+  const { user: currentUser, logout } = useAuth()
+  const { t, lang, setLang } = useLanguage()
+  const userLevel = ROLE_LEVEL[currentUser?.role] ?? 0
+
+  const visibleItems = navItems.filter(item => {
+    if (!item.minRole) return true
+    return userLevel >= (ROLE_LEVEL[item.minRole] ?? 0)
+  })
+
+  return (
+    <aside
+      className={`sidebar fixed top-0 h-screen bg-sidebar flex flex-col z-30 transition-all duration-300 ${
+        collapsed ? 'w-[68px]' : 'w-[260px]'
+      }`}
+    >
+      {/* Logo */}
+      <div className="flex items-center gap-3 px-4 h-16 border-b border-white/10 shrink-0">
+        <div className="w-9 h-9 rounded-lg bg-gradient-to-br from-indigo-400 to-purple-500 flex items-center justify-center shrink-0">
+          <Sparkles className="w-5 h-5 text-white" />
+        </div>
+        {!collapsed && (
+          <div className="animate-fade-in overflow-hidden">
+            <h1 className="text-white font-bold text-sm leading-tight whitespace-nowrap">{t('app.name')}</h1>
+            <p className="text-text-on-dark-muted text-xs whitespace-nowrap">{t('app.subtitle')}</p>
+          </div>
+        )}
+      </div>
+
+      {/* Navigation */}
+      <nav className="flex-1 py-4 px-3 space-y-1 overflow-y-auto">
+        {visibleItems.map(({ to, icon: Icon, labelKey, end, tutorial }) => (
+          <NavLink
+            key={to}
+            to={to}
+            end={end}
+            data-tutorial={tutorial}
+            className={({ isActive }) =>
+              `flex items-center gap-3 px-3 py-2.5 rounded-lg text-sm font-medium transition-all duration-200 group ${
+                isActive
+                  ? 'bg-white/15 text-white shadow-sm'
+                  : 'text-text-on-dark-muted hover:bg-white/8 hover:text-white'
+              }`
+            }
+          >
+            <Icon className="w-5 h-5 shrink-0" />
+            {!collapsed && <span className="animate-fade-in whitespace-nowrap">{t(labelKey)}</span>}
+          </NavLink>
+        ))}
+        
+        {/* Superadmin Only: Users Management */}
+        {currentUser?.role === 'superadmin' && (
+          <NavLink
+            to="/users"
+            className={({ isActive }) =>
+              `flex items-center gap-3 px-3 py-2.5 rounded-lg text-sm font-medium transition-all duration-200 group ${
+                isActive
+                  ? 'bg-white/15 text-white shadow-sm'
+                  : 'text-text-on-dark-muted hover:bg-white/8 hover:text-white'
+              }`
+            }
+          >
+            <Shield className="w-5 h-5 shrink-0" />
+            {!collapsed && <span className="animate-fade-in whitespace-nowrap">{t('nav.users')}</span>}
+          </NavLink>
+        )}
+
+        {/* Settings (visible to all) */}
+        <NavLink
+          to="/settings"
+          className={({ isActive }) =>
+            `flex items-center gap-3 px-3 py-2.5 rounded-lg text-sm font-medium transition-all duration-200 group ${
+              isActive
+                ? 'bg-white/15 text-white shadow-sm'
+                : 'text-text-on-dark-muted hover:bg-white/8 hover:text-white'
+            }`
+          }
+        >
+          <Settings className="w-5 h-5 shrink-0" />
+          {!collapsed && <span className="animate-fade-in whitespace-nowrap">{t('nav.settings')}</span>}
+        </NavLink>
+      </nav>
+
+      {/* Current User & Logout */}
+      <div className="border-t border-white/10 shrink-0">
+        {currentUser && !collapsed && (
+          <div className="p-3 border-b border-white/10">
+            <div className="flex items-center gap-3 px-3 py-2 rounded-lg bg-white/5">
+              <div className="w-8 h-8 rounded-full bg-brand-primary flex items-center justify-center shrink-0">
+                {currentUser.avatar ? (
+                  <img src={currentUser.avatar} alt={currentUser.name} className="w-full h-full rounded-full object-cover" />
+                ) : (
+                  <User className="w-4 h-4 text-white" />
+                )}
+              </div>
+              <div className="flex-1 min-w-0 animate-fade-in">
+                <p className="text-white text-sm font-medium truncate">{currentUser.name}</p>
+                <p className="text-text-on-dark-muted text-xs truncate capitalize">{currentUser.role}</p>
+              </div>
+            </div>
+          </div>
+        )}
+        
+        {!collapsed && (
+          <>
+            {/* Language Toggle */}
+            <div className="px-3 pb-3">
+              <button
+                onClick={() => setLang(lang === 'en' ? 'ar' : 'en')}
+                className="w-full flex items-center gap-2 px-3 py-2 rounded-lg text-text-on-dark-muted hover:bg-white/8 hover:text-white transition-colors text-sm"
+              >
+                <Languages className="w-4 h-4" />
+                <span className="animate-fade-in">{lang === 'en' ? 'عربي' : 'English'}</span>
+              </button>
+            </div>
+
+            {/* Logout */}
+            <div className="px-3 pb-3">
+              <button
+                onClick={logout}
+                className="w-full flex items-center gap-2 px-3 py-2 rounded-lg text-text-on-dark-muted hover:bg-white/8 hover:text-white transition-colors text-sm"
+              >
+                <LogOut className="w-4 h-4" />
+                <span className="animate-fade-in">{t('nav.logout')}</span>
+              </button>
+            </div>
+          </>
+        )}
+        
+        {/* Collapse toggle */}
+        <div className="p-3 border-t border-white/10">
+          <button
+            onClick={() => setCollapsed(!collapsed)}
+            className="w-full flex items-center justify-center gap-2 px-3 py-2 rounded-lg text-text-on-dark-muted hover:bg-white/8 hover:text-white transition-colors text-sm"
+          >
+            {collapsed ? <ChevronRight className="w-4 h-4" /> : (
+              <>
+                <ChevronLeft className="w-4 h-4" />
+                <span className="animate-fade-in">{t('nav.collapse')}</span>
+              </>
+            )}
+          </button>
+        </div>
+      </div>
+    </aside>
+  )
+}
diff --git a/client/src/components/StatCard.jsx b/client/src/components/StatCard.jsx
new file mode 100644
index 0000000..b13916f
--- /dev/null
+++ b/client/src/components/StatCard.jsx
@@ -0,0 +1,42 @@
+export default function StatCard({ icon: Icon, label, value, subtitle, color = 'brand-primary', trend }) {
+  const colorMap = {
+    'brand-primary': 'from-indigo-500 to-indigo-600',
+    'brand-secondary': 'from-pink-500 to-pink-600',
+    'brand-tertiary': 'from-amber-500 to-amber-600',
+    'brand-quaternary': 'from-emerald-500 to-emerald-600',
+  }
+
+  const iconBgMap = {
+    'brand-primary': 'bg-indigo-50 text-indigo-600',
+    'brand-secondary': 'bg-pink-50 text-pink-600',
+    'brand-tertiary': 'bg-amber-50 text-amber-600',
+    'brand-quaternary': 'bg-emerald-50 text-emerald-600',
+  }
+
+  return (
+    <div className="bg-white rounded-xl border border-border p-5 card-hover">
+      <div className="flex items-start justify-between">
+        <div>
+          <p className="text-sm font-medium text-text-tertiary">{label}</p>
+          <p className="text-3xl font-bold text-text-primary mt-1">{value}</p>
+          {subtitle && (
+            <p className="text-xs text-text-tertiary mt-1">{subtitle}</p>
+          )}
+        </div>
+        <div className={`w-11 h-11 rounded-xl flex items-center justify-center ${iconBgMap[color] || iconBgMap['brand-primary']}`}>
+          <Icon className="w-5 h-5" />
+        </div>
+      </div>
+      {trend && (
+        <div className="mt-3 pt-3 border-t border-border-light">
+          <div className="flex items-center gap-1">
+            <span className={`text-xs font-medium ${trend > 0 ? 'text-emerald-600' : 'text-red-500'}`}>
+              {trend > 0 ? '+' : ''}{trend}%
+            </span>
+            <span className="text-xs text-text-tertiary">vs last month</span>
+          </div>
+        </div>
+      )}
+    </div>
+  )
+}
diff --git a/client/src/components/StatusBadge.jsx b/client/src/components/StatusBadge.jsx
new file mode 100644
index 0000000..0b60573
--- /dev/null
+++ b/client/src/components/StatusBadge.jsx
@@ -0,0 +1,34 @@
+import { getStatusConfig } from '../utils/api'
+import { useLanguage } from '../i18n/LanguageContext'
+
+const STATUS_LABEL_MAP = {
+  'draft': 'posts.status.draft',
+  'in_review': 'posts.status.in_review',
+  'approved': 'posts.status.approved',
+  'scheduled': 'posts.status.scheduled',
+  'published': 'posts.status.published',
+  'todo': 'tasks.todo',
+  'in_progress': 'tasks.in_progress',
+  'done': 'tasks.done',
+}
+
+export default function StatusBadge({ status, size = 'sm' }) {
+  const { t } = useLanguage()
+  const config = getStatusConfig(status)
+  
+  const sizeClasses = {
+    xs: 'text-[10px] px-1.5 py-0.5',
+    sm: 'text-xs px-2 py-1',
+    md: 'text-sm px-2.5 py-1',
+  }
+
+  const labelKey = STATUS_LABEL_MAP[status]
+  const label = labelKey ? t(labelKey) : config.label
+
+  return (
+    <span className={`inline-flex items-center gap-1.5 rounded-full font-medium ${config.bg} ${config.text} ${sizeClasses[size]}`}>
+      <span className={`w-1.5 h-1.5 rounded-full ${config.dot}`}></span>
+      {label}
+    </span>
+  )
+}
diff --git a/client/src/components/TaskCard.jsx b/client/src/components/TaskCard.jsx
new file mode 100644
index 0000000..cb02a0c
--- /dev/null
+++ b/client/src/components/TaskCard.jsx
@@ -0,0 +1,93 @@
+import { format } from 'date-fns'
+import { ArrowRight, Clock, User, UserCheck } from 'lucide-react'
+import { PRIORITY_CONFIG } from '../utils/api'
+import { useAuth } from '../contexts/AuthContext'
+import { useLanguage } from '../i18n/LanguageContext'
+
+export default function TaskCard({ task, onMove, showProject = true }) {
+  const { t } = useLanguage()
+  const { user: authUser } = useAuth()
+  const priority = PRIORITY_CONFIG[task.priority] || PRIORITY_CONFIG.medium
+  const projectName = typeof task.project === 'object' ? task.project?.name : task.projectName
+
+  const nextStatus = {
+    todo: 'in_progress',
+    in_progress: 'done',
+  }
+
+  const nextLabel = {
+    todo: t('tasks.start'),
+    in_progress: t('tasks.complete'),
+  }
+
+  const dueDate = task.due_date || task.dueDate
+  const isOverdue = dueDate && new Date(dueDate) < new Date() && task.status !== 'done'
+  const creatorName = task.creator_user_name || task.creatorUserName
+
+  // Determine if this task was assigned by someone else
+  const createdByUserId = task.created_by_user_id || task.createdByUserId
+  const isExternallyAssigned = authUser && createdByUserId && createdByUserId !== authUser.id
+  const assignedName = task.assigned_name || task.assignedName
+
+  return (
+    <div className={`bg-white rounded-lg border border-border p-3 card-hover group ${isExternallyAssigned ? 'border-l-[3px] border-l-blue-400' : ''}`}>
+      <div className="flex items-start gap-2.5">
+        {/* Priority dot */}
+        <div className={`w-2.5 h-2.5 rounded-full ${priority.color} mt-1.5 shrink-0`} title={priority.label} />
+
+        <div className="flex-1 min-w-0">
+          <h5 className={`text-sm font-medium leading-snug ${task.status === 'done' ? 'text-text-tertiary line-through' : 'text-text-primary'}`}>
+            {task.title}
+          </h5>
+
+          {/* Assigned by label for externally-assigned tasks */}
+          {isExternallyAssigned && creatorName && (
+            <div className="flex items-center gap-1 mt-1">
+              <UserCheck className="w-3 h-3 text-blue-400" />
+              <span className="text-[10px] text-blue-500 font-medium">{t('tasks.from')} {creatorName}</span>
+            </div>
+          )}
+          {/* Assigned to label for tasks you delegated */}
+          {!isExternallyAssigned && assignedName && (
+            <div className="flex items-center gap-1 mt-1">
+              <User className="w-3 h-3 text-emerald-400" />
+              <span className="text-[10px] text-emerald-500 font-medium">{t('tasks.assignedTo')} {assignedName}</span>
+            </div>
+          )}
+
+          <div className="flex items-center gap-2 mt-1.5 flex-wrap">
+            {showProject && projectName && (
+              <span className="text-[10px] px-1.5 py-0.5 rounded bg-surface-tertiary text-text-tertiary">
+                {projectName}
+              </span>
+            )}
+            {dueDate && (
+              <span className={`text-[10px] flex items-center gap-1 ${isOverdue ? 'text-red-500 font-medium' : 'text-text-tertiary'}`}>
+                <Clock className="w-3 h-3" />
+                {format(new Date(dueDate), 'MMM d')}
+              </span>
+            )}
+            {!isExternallyAssigned && creatorName && (
+              <span className="text-[10px] flex items-center gap-1 text-text-tertiary">
+                <User className="w-3 h-3" />
+                {creatorName}
+              </span>
+            )}
+          </div>
+        </div>
+      </div>
+
+      {/* Quick action */}
+      {onMove && nextStatus[task.status] && (
+        <div className="mt-2 pt-2 border-t border-border-light opacity-0 group-hover:opacity-100 transition-opacity">
+          <button
+            onClick={() => onMove(task._id || task.id, nextStatus[task.status])}
+            className="text-[11px] text-brand-primary hover:text-brand-primary-light font-medium flex items-center gap-1"
+          >
+            {nextLabel[task.status]} <ArrowRight className="w-3 h-3" />
+          </button>
+        </div>
+      )}
+    </div>
+  )
+}
diff --git a/client/src/components/Tutorial.jsx b/client/src/components/Tutorial.jsx
new file mode 100644
index 0000000..0dcec56
--- /dev/null
+++ b/client/src/components/Tutorial.jsx
@@ -0,0 +1,248 @@
+import { useState, useEffect } from 'react'
+import { X, ArrowLeft, ArrowRight } from 'lucide-react'
+import { useLanguage } from '../i18n/LanguageContext'
+
+const getTutorialSteps = (t) => [
+  {
+    target: '[data-tutorial="dashboard"]',
+    title: t('tutorial.dashboard.title'),
+    description: t('tutorial.dashboard.desc'),
+    position: 'right',
+  },
+  {
+    target: '[data-tutorial="campaigns"]',
+    title: t('tutorial.campaigns.title'),
+    description: t('tutorial.campaigns.desc'),
+    position: 'right',
+  },
+  {
+    target: '[data-tutorial="posts"]',
+    title: t('tutorial.posts.title'),
+    description: t('tutorial.posts.desc'),
+    position: 'right',
+  },
+  {
+    target: '[data-tutorial="tasks"]',
+    title: t('tutorial.tasks.title'),
+    description: t('tutorial.tasks.desc'),
+    position: 'right',
+  },
+  {
+    target: '[data-tutorial="team"]',
+    title: t('tutorial.team.title'),
+    description: t('tutorial.team.desc'),
+    position: 'right',
+  },
+  {
+    target: '[data-tutorial="assets"]',
+    title: t('tutorial.assets.title'),
+    description: t('tutorial.assets.desc'),
+    position: 'right',
+  },
+  {
+    target: '[data-tutorial="new-post"]',
+    title: t('tutorial.newPost.title'),
+    description: t('tutorial.newPost.desc'),
+    position: 'bottom',
+  },
+  {
+    target: '[data-tutorial="filters"]',
+    title: t('tutorial.filters.title'),
+    description: t('tutorial.filters.desc'),
+    position: 'bottom',
+  },
+]
+
+export default function Tutorial({ onComplete }) {
+  const { t } = useLanguage()
+  const [currentStep, setCurrentStep] = useState(0)
+  const [targetRect, setTargetRect] = useState(null)
+  const [tooltipPosition, setTooltipPosition] = useState({ top: 0, left: 0 })
+
+  const TUTORIAL_STEPS = getTutorialSteps(t)
+  const step = TUTORIAL_STEPS[currentStep]
+
+  useEffect(() => {
+    updatePosition()
+    window.addEventListener('resize', updatePosition)
+    return () => window.removeEventListener('resize', updatePosition)
+  }, [currentStep])
+
+  const updatePosition = () => {
+    const target = document.querySelector(step.target)
+    if (!target) {
+      console.warn(`Tutorial target not found: ${step.target}`)
+      return
+    }
+
+    const rect = target.getBoundingClientRect()
+    setTargetRect(rect)
+
+    // Calculate tooltip position
+    const tooltipWidth = 360
+    const tooltipHeight = 200
+    const padding = 20
+
+    let top = rect.top
+    let left = rect.right + padding
+
+    // Adjust based on position hint
+    if (step.position === 'bottom') {
+      top = rect.bottom + padding
+      left = rect.left
+    } else if (step.position === 'left') {
+      top = rect.top
+      left = rect.left - tooltipWidth - padding
+    } else if (step.position === 'top') {
+      top = rect.top - tooltipHeight - padding
+      left = rect.left
+    }
+
+    // Keep tooltip on screen
+    if (left + tooltipWidth > window.innerWidth) {
+      left = rect.left - tooltipWidth - padding
+    }
+    if (left < 0) {
+      left = padding
+    }
+    if (top + tooltipHeight > window.innerHeight) {
+      top = window.innerHeight - tooltipHeight - padding
+    }
+    if (top < 0) {
+      top = padding
+    }
+
+    setTooltipPosition({ top, left })
+  }
+
+  const handleNext = () => {
+    if (currentStep < TUTORIAL_STEPS.length - 1) {
+      setCurrentStep(currentStep + 1)
+    } else {
+      onComplete()
+    }
+  }
+
+  const handlePrev = () => {
+    if (currentStep > 0) {
+      setCurrentStep(currentStep - 1)
+    }
+  }
+
+  const handleSkip = () => {
+    onComplete()
+  }
+
+  if (!targetRect) return null
+
+  return (
+    <div className="fixed inset-0 z-[9999] pointer-events-none">
+      {/* Dark overlay with spotlight cutout */}
+      <svg className="absolute inset-0 w-full h-full pointer-events-auto" style={{ pointerEvents: 'auto' }}>
+        <defs>
+          <mask id="tutorial-mask">
+            <rect x="0" y="0" width="100%" height="100%" fill="white" />
+            <rect
+              x={targetRect.left - 4}
+              y={targetRect.top - 4}
+              width={targetRect.width + 8}
+              height={targetRect.height + 8}
+              rx="8"
+              fill="black"
+            />
+          </mask>
+        </defs>
+        <rect
+          x="0"
+          y="0"
+          width="100%"
+          height="100%"
+          fill="rgba(0, 0, 0, 0.7)"
+          mask="url(#tutorial-mask)"
+          onClick={handleSkip}
+          style={{ cursor: 'pointer' }}
+        />
+      </svg>
+
+      {/* Highlight ring around target */}
+      <div
+        className="absolute border-4 border-brand-primary rounded-lg shadow-lg transition-all duration-300 pointer-events-none"
+        style={{
+          top: targetRect.top - 4,
+          left: targetRect.left - 4,
+          width: targetRect.width + 8,
+          height: targetRect.height + 8,
+        }}
+      />
+
+      {/* Tooltip card */}
+      <div
+        className="absolute bg-white rounded-xl shadow-2xl border border-border p-6 animate-fade-in pointer-events-auto"
+        style={{
+          top: tooltipPosition.top,
+          left: tooltipPosition.left,
+          width: 360,
+          maxWidth: 'calc(100vw - 40px)',
+        }}
+      >
+        {/* Close button */}
+        <button
+          onClick={handleSkip}
+          className="absolute top-4 right-4 text-text-tertiary hover:text-text-primary transition-colors"
+        >
+          <X className="w-5 h-5" />
+        </button>
+
+        {/* Content */}
+        <div className="space-y-4">
+          <div>
+            <div className="flex items-center gap-2 text-xs font-medium text-brand-primary mb-2">
+              <span className="inline-flex items-center justify-center w-6 h-6 rounded-full bg-brand-primary/10 text-brand-primary text-xs font-bold">
+                {currentStep + 1}
+              </span>
+              <span>{t('tutorial.step')} {currentStep + 1} {t('tutorial.of')} {TUTORIAL_STEPS.length}</span>
+            </div>
+            <h3 className="text-xl font-bold text-text-primary mb-2">{step.title}</h3>
+            <p className="text-sm text-text-secondary leading-relaxed">{step.description}</p>
+          </div>
+
+          {/* Progress bar */}
+          <div className="w-full h-1.5 bg-surface-tertiary rounded-full overflow-hidden">
+            <div
+              className="h-full bg-gradient-to-r from-brand-primary to-purple-500 transition-all duration-300"
+              style={{ width: `${((currentStep + 1) / TUTORIAL_STEPS.length) * 100}%` }}
+            />
+          </div>
+
+          {/* Navigation */}
+          <div className="flex items-center justify-between gap-3 pt-2">
+            <button
+              onClick={handleSkip}
+              className="text-sm font-medium text-text-tertiary hover:text-text-primary transition-colors"
+            >
+              {t('tutorial.skip')}
+            </button>
+            <div className="flex items-center gap-2">
+              {currentStep > 0 && (
+                <button
+                  onClick={handlePrev}
+                  className="flex items-center gap-1.5 px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg transition-colors"
+                >
+                  <ArrowLeft className="w-4 h-4" />
+                  {t('tutorial.prev')}
+                </button>
+              )}
+              <button
+                onClick={handleNext}
+                className="flex items-center gap-1.5 px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm transition-colors"
+              >
+                {currentStep < TUTORIAL_STEPS.length - 1 ? t('tutorial.next') : t('tutorial.finish')}
+                {currentStep < TUTORIAL_STEPS.length - 1 && <ArrowRight className="w-4 h-4" />}
+              </button>
+            </div>
+          </div>
+        </div>
+      </div>
+    </div>
+  )
+}
diff --git a/client/src/contexts/AuthContext.jsx b/client/src/contexts/AuthContext.jsx
new file mode 100644
index 0000000..0507885
--- /dev/null
+++ b/client/src/contexts/AuthContext.jsx
@@ -0,0 +1,104 @@
+import { createContext, useState, useEffect, useContext } from 'react'
+import { api } from '../utils/api'
+
+const AuthContext = createContext(null)
+
+export function AuthProvider({ children }) {
+  const [user, setUser] = useState(null)
+  const [permissions, setPermissions] = useState(null)
+  const [loading, setLoading] = useState(true)
+
+  useEffect(() => {
+    checkAuth()
+  }, [])
+
+  const checkAuth = async () => {
+    try {
+      const userData = await api.get('/auth/me')
+      setUser(userData)
+      const perms = await api.get('/auth/permissions')
+      setPermissions(perms)
+    } catch (err) {
+      console.log('Not authenticated')
+      setUser(null)
+      setPermissions(null)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const login = async (email, password) => {
+    const response = await api.post('/auth/login', { email, password })
+    setUser(response.user)
+    // Load permissions after login
+    try {
+      const perms = await api.get('/auth/permissions')
+      setPermissions(perms)
+    } catch (err) {
+      console.error('Failed to load permissions:', err)
+    }
+    return response
+  }
+
+  const logout = async () => {
+    try {
+      await api.post('/auth/logout')
+    } catch (err) {
+      console.error('Logout error:', err)
+    } finally {
+      setUser(null)
+      setPermissions(null)
+      window.location.href = '/login'
+    }
+  }
+
+  // Check if current user owns a resource
+  const isOwner = (resource) => {
+    if (!user || !resource) return false
+    return resource.created_by_user_id === user.id
+  }
+
+  // Check if current user is assigned to a resource
+  const isAssignedTo = (resource) => {
+    if (!user || !resource) return false
+    const teamMemberId = user.team_member_id || user.teamMemberId
+    if (!teamMemberId) return false
+    const assignedTo = resource.assigned_to || resource.assignedTo
+    return assignedTo === teamMemberId
+  }
+
+  // Check if user can edit a specific resource (owns it, assigned to it, or has role)
+  const canEditResource = (type, resource) => {
+    if (!permissions) return false
+    if (type === 'post') return permissions.canEditAnyPost || isOwner(resource) || isAssignedTo(resource)
+    if (type === 'task') return permissions.canEditAnyTask || isOwner(resource) || isAssignedTo(resource)
+    return false
+  }
+
+  const canDeleteResource = (type, resource) => {
+    if (!permissions) return false
+    if (type === 'post') return permissions.canDeleteAnyPost || isOwner(resource) || isAssignedTo(resource)
+    if (type === 'task') return permissions.canDeleteAnyTask || isOwner(resource) || isAssignedTo(resource)
+    return false
+  }
+
+  return (
+    <AuthContext.Provider value={{
+      user, loading, permissions,
+      login, logout, checkAuth,
+      isOwner, canEditResource, canDeleteResource,
+    }}>
+      {children}
+    </AuthContext.Provider>
+  )
+}
+
+export function useAuth() {
+  const context = useContext(AuthContext)
+  if (!context) {
+    throw new Error('useAuth must be used within AuthProvider')
+  }
+  return context
+}
+
+export default AuthContext
diff --git a/client/src/i18n/LanguageContext.jsx b/client/src/i18n/LanguageContext.jsx
new file mode 100644
index 0000000..9e9ceb5
--- /dev/null
+++ b/client/src/i18n/LanguageContext.jsx
@@ -0,0 +1,65 @@
+import { createContext, useContext, useState, useEffect } from 'react'
+import en from './en.json'
+import ar from './ar.json'
+
+const translations = { en, ar }
+
+const LanguageContext = createContext()
+
+export function LanguageProvider({ children }) {
+  const [lang, setLangState] = useState(() => {
+    // Load from localStorage or default to 'en'
+    return localStorage.getItem('samaya-lang') || 'en'
+  })
+
+  const setLang = (newLang) => {
+    if (newLang !== 'en' && newLang !== 'ar') return
+    setLangState(newLang)
+    localStorage.setItem('samaya-lang', newLang)
+  }
+
+  const dir = lang === 'ar' ? 'rtl' : 'ltr'
+
+  // Update HTML dir attribute whenever language changes
+  useEffect(() => {
+    document.documentElement.dir = dir
+    document.documentElement.lang = lang
+  }, [dir, lang])
+
+  // Translation function
+  const t = (key) => {
+    const keys = key.split('.')
+    let value = translations[lang]
+    
+    for (const k of keys) {
+      value = value?.[k]
+      if (value === undefined) break
+    }
+    
+    // Fallback to English if translation not found
+    if (value === undefined) {
+      value = translations.en
+      for (const k of keys) {
+        value = value?.[k]
+        if (value === undefined) break
+      }
+    }
+    
+    // Fallback to key itself if still not found
+    return value !== undefined ? value : key
+  }
+
+  return (
+    <LanguageContext.Provider value={{ lang, setLang, t, dir }}>
+      {children}
+    </LanguageContext.Provider>
+  )
+}
+
+export function useLanguage() {
+  const context = useContext(LanguageContext)
+  if (!context) {
+    throw new Error('useLanguage must be used within a LanguageProvider')
+  }
+  return context
+}
diff --git a/client/src/i18n/ar.json b/client/src/i18n/ar.json
new file mode 100644
index 0000000..f50b09e
--- /dev/null
+++ b/client/src/i18n/ar.json
@@ -0,0 +1,239 @@
+{
+  "app.name": "سمايا",
+  "app.subtitle": "مركز التسويق",
+  "nav.dashboard": "لوحة التحكم",
+  "nav.campaigns": "الحملات",
+  "nav.finance": "المالية والعائد",
+  "nav.posts": "إنتاج المحتوى",
+  "nav.assets": "الأصول",
+  "nav.projects": "المشاريع",
+  "nav.tasks": "المهام",
+  "nav.team": "الفريق",
+  "nav.settings": "الإعدادات",
+  "nav.users": "المستخدمين",
+  "nav.logout": "تسجيل الخروج",
+  "nav.collapse": "طي",
+  
+  "common.save": "حفظ",
+  "common.cancel": "إلغاء",
+  "common.delete": "حذف",
+  "common.edit": "تعديل",
+  "common.create": "إنشاء",
+  "common.search": "بحث...",
+  "common.filter": "تصفية",
+  "common.all": "الكل",
+  "common.noResults": "لا توجد نتائج",
+  "common.loading": "جاري التحميل...",
+  "common.unassigned": "غير مُسند",
+  "common.required": "مطلوب",
+  
+  "auth.login": "تسجيل الدخول",
+  "auth.email": "البريد الإلكتروني",
+  "auth.password": "كلمة المرور",
+  "auth.loginBtn": "دخول",
+  "auth.signingIn": "جاري تسجيل الدخول...",
+  
+  "dashboard.title": "لوحة التحكم",
+  "dashboard.welcomeBack": "مرحباً بعودتك",
+  "dashboard.happeningToday": "إليك ما يحدث مع تسويقك اليوم.",
+  "dashboard.totalPosts": "إجمالي المنشورات",
+  "dashboard.published": "منشور",
+  "dashboard.activeCampaigns": "الحملات النشطة",
+  "dashboard.total": "إجمالي",
+  "dashboard.budgetSpent": "الميزانية المنفقة",
+  "dashboard.of": "من",
+  "dashboard.noBudget": "لا توجد ميزانية بعد",
+  "dashboard.overdueTasks": "مهام متأخرة",
+  "dashboard.needsAttention": "يحتاج اهتماماً",
+  "dashboard.allOnTrack": "كل شيء على المسار الصحيح",
+  "dashboard.budgetOverview": "نظرة عامة على الميزانية",
+  "dashboard.details": "التفاصيل",
+  "dashboard.noBudgetRecorded": "لم يتم تسجيل ميزانية بعد.",
+  "dashboard.addBudget": "إضافة ميزانية",
+  "dashboard.spent": "مُنفق",
+  "dashboard.received": "مُستلم",
+  "dashboard.remaining": "المتبقي",
+  "dashboard.revenue": "الإيرادات",
+  "dashboard.roi": "العائد على الاستثمار",
+  "dashboard.recentPosts": "المنشورات الأخيرة",
+  "dashboard.viewAll": "عرض الكل",
+  "dashboard.sar": "ريال",
+  "dashboard.noPostsYet": "لا توجد منشورات بعد. أنشئ منشورك الأول!",
+  "dashboard.upcomingDeadlines": "المواعيد النهائية القادمة",
+  "dashboard.noUpcomingDeadlines": "لا توجد مواعيد نهائية هذا الأسبوع. 🎉",
+  "dashboard.loadingHub": "جاري تحميل مركز سمايا للتسويق...",
+  
+  "posts.title": "إنتاج المحتوى",
+  "posts.newPost": "منشور جديد",
+  "posts.editPost": "تعديل المنشور",
+  "posts.createPost": "إنشاء منشور",
+  "posts.saveChanges": "حفظ التغييرات",
+  "posts.postTitle": "العنوان",
+  "posts.description": "الوصف",
+  "posts.brand": "العلامة التجارية",
+  "posts.platforms": "المنصات",
+  "posts.status": "الحالة",
+  "posts.assignTo": "إسناد إلى",
+  "posts.scheduledDate": "تاريخ النشر المجدول",
+  "posts.notes": "ملاحظات",
+  "posts.campaign": "الحملة",
+  "posts.noCampaign": "بدون حملة",
+  "posts.publicationLinks": "روابط النشر",
+  "posts.attachments": "المرفقات",
+  "posts.uploadFiles": "انقر أو اسحب الملفات للرفع",
+  "posts.dropFiles": "أسقط الملفات هنا",
+  "posts.maxSize": "الحد الأقصى 50 ميجابايت للملف",
+  "posts.allBrands": "جميع العلامات",
+  "posts.allPlatforms": "جميع المنصات",
+  "posts.allPeople": "جميع الأشخاص",
+  "posts.searchPosts": "بحث في المنشورات...",
+  "posts.deletePost": "حذف المنشور؟",
+  "posts.deleteConfirm": "هل أنت متأكد من حذف هذا المنشور؟ لا يمكن التراجع.",
+  "posts.publishMissing": "لا يمكن النشر: روابط النشر مفقودة لـ:",
+  "posts.publishRequired": "جميع روابط النشر مطلوبة للنشر",
+  "posts.noPostsFound": "لم يتم العثور على منشورات",
+  "posts.selectBrand": "اختر العلامة التجارية",
+  "posts.additionalNotes": "ملاحظات إضافية",
+  "posts.uploading": "جاري الرفع...",
+  "posts.deleteAttachment": "حذف المرفق",
+  "posts.whatNeedsDone": "ما الذي يجب القيام به؟",
+  "posts.optionalDetails": "تفاصيل اختيارية...",
+  "posts.postTitlePlaceholder": "عنوان المنشور",
+  "posts.postDescPlaceholder": "وصف المنشور...",
+  "posts.dropHere": "أسقط هنا",
+  "posts.noPosts": "لا توجد منشورات",
+  "posts.sendToReview": "إرسال للمراجعة",
+  "posts.approve": "اعتماد",
+  "posts.schedule": "جدولة",
+  "posts.publish": "نشر",
+  
+  "posts.status.draft": "مسودة",
+  "posts.status.in_review": "قيد المراجعة",
+  "posts.status.approved": "مُعتمد",
+  "posts.status.scheduled": "مجدول",
+  "posts.status.published": "منشور",
+  
+  "tasks.title": "المهام",
+  "tasks.newTask": "مهمة جديدة",
+  "tasks.editTask": "تعديل المهمة",
+  "tasks.createTask": "إنشاء مهمة",
+  "tasks.saveChanges": "حفظ التغييرات",
+  "tasks.taskTitle": "العنوان",
+  "tasks.description": "الوصف",
+  "tasks.priority": "الأولوية",
+  "tasks.dueDate": "تاريخ الاستحقاق",
+  "tasks.assignTo": "إسناد إلى",
+  "tasks.allTasks": "جميع المهام",
+  "tasks.assignedToMe": "المُسندة إليّ",
+  "tasks.createdByMe": "أنشأتها",
+  "tasks.byTeamMember": "حسب عضو الفريق",
+  "tasks.noTasks": "لا توجد مهام بعد",
+  "tasks.noMatch": "لا توجد مهام تطابق هذا الفلتر",
+  "tasks.createFirst": "أنشئ مهمة للبدء",
+  "tasks.tryFilter": "جرب فلتر مختلف",
+  "tasks.deleteTask": "حذف المهمة؟",
+  "tasks.deleteConfirm": "هل أنت متأكد من حذف هذه المهمة؟ لا يمكن التراجع.",
+  "tasks.todo": "للتنفيذ",
+  "tasks.in_progress": "قيد التنفيذ",
+  "tasks.done": "مكتمل",
+  "tasks.start": "ابدأ",
+  "tasks.complete": "أكمل",
+  "tasks.from": "من:",
+  "tasks.assignedTo": "مُسند إلى:",
+  "tasks.task": "مهمة",
+  "tasks.tasks": "مهام",
+  "tasks.of": "من",
+  
+  "tasks.priority.low": "منخفض",
+  "tasks.priority.medium": "متوسط",
+  "tasks.priority.high": "عالي",
+  "tasks.priority.urgent": "عاجل",
+  
+  "team.title": "الفريق",
+  "team.members": "أعضاء الفريق",
+  "team.addMember": "إضافة عضو",
+  "team.newMember": "عضو جديد",
+  "team.editMember": "تعديل العضو",
+  "team.myProfile": "ملفي الشخصي",
+  "team.editProfile": "تعديل ملفي",
+  "team.name": "الاسم",
+  "team.email": "البريد الإلكتروني",
+  "team.password": "كلمة المرور",
+  "team.teamRole": "الدور في الفريق",
+  "team.phone": "الهاتف",
+  "team.brands": "العلامات التجارية",
+  "team.brandsHelp": "أسماء العلامات مفصولة بفاصلة",
+  "team.removeMember": "إزالة عضو الفريق؟",
+  "team.removeConfirm": "هل أنت متأكد من إزالة {name}؟ لا يمكن التراجع.",
+  "team.noMembers": "لا يوجد أعضاء",
+  "team.backToTeam": "العودة للفريق",
+  "team.totalTasks": "إجمالي المهام",
+  "team.saveProfile": "حفظ الملف",
+  "team.saveChanges": "حفظ التغييرات",
+  "team.member": "عضو فريق",
+  "team.membersPlural": "أعضاء فريق",
+  "team.fullName": "الاسم الكامل",
+  "team.defaultPassword": "افتراضياً: changeme123",
+  "team.optional": "(اختياري)",
+  "team.fixedRole": "دور ثابت للمديرين",
+  "team.remove": "إزالة",
+  "team.noTasks": "لا توجد مهام",
+  "team.toDo": "للتنفيذ",
+  "team.inProgress": "قيد التنفيذ",
+  
+  "campaigns.title": "الحملات",
+  "campaigns.newCampaign": "حملة جديدة",
+  "campaigns.noCampaigns": "لا توجد حملات",
+  
+  "assets.title": "الأصول",
+  "assets.upload": "رفع",
+  "assets.noAssets": "لا توجد أصول",
+  
+  "settings.title": "الإعدادات",
+  "settings.language": "اللغة",
+  "settings.english": "English",
+  "settings.arabic": "عربي",
+  "settings.restartTutorial": "إعادة تشغيل الدليل التعليمي",
+  "settings.tutorialDesc": "هل تحتاج إلى تذكير؟ أعد تشغيل الدليل التفاعلي للتعرف على جميع ميزات مركز سمايا للتسويق.",
+  "settings.general": "عام",
+  "settings.onboardingTutorial": "الدليل التعليمي",
+  "settings.tutorialRestarted": "تم إعادة تشغيل الدليل!",
+  "settings.restarting": "جاري إعادة التشغيل...",
+  "settings.reloadingPage": "جاري إعادة تحميل الصفحة لبدء الدليل...",
+  "settings.moreComingSoon": "المزيد من الإعدادات قريباً",
+  "settings.additionalSettings": "سيتم إضافة إعدادات إضافية للإشعارات وتفضيلات العرض والمزيد هنا.",
+  "settings.preferences": "إدارة تفضيلاتك وإعدادات التطبيق",
+  
+  "tutorial.skip": "تخطي",
+  "tutorial.next": "التالي",
+  "tutorial.prev": "السابق",
+  "tutorial.finish": "إنهاء",
+  "tutorial.of": "من",
+  "tutorial.step": "الخطوة",
+  "tutorial.dashboard.title": "لوحة التحكم",
+  "tutorial.dashboard.desc": "مركز القيادة الخاص بك. شاهد أداء الحملات وتقدم المهام ونشاط الفريق في لمحة.",
+  "tutorial.campaigns.title": "الحملات",
+  "tutorial.campaigns.desc": "خطط وأدر الحملات التسويقية عبر جميع العلامات والمنصات.",
+  "tutorial.posts.title": "إنتاج المحتوى",
+  "tutorial.posts.desc": "أنشئ وراجع وانشر المحتوى. اسحب المنشورات عبر خط سير العمل.",
+  "tutorial.tasks.title": "المهام",
+  "tutorial.tasks.desc": "أسند وتتبع المهام. صفّ حسب من أسندها أو من أُسندت إليه.",
+  "tutorial.team.title": "الفريق",
+  "tutorial.team.desc": "دليل فريقك. أكمل ملفك الشخصي وشاهد من تعمل معه.",
+  "tutorial.assets.title": "الأصول",
+  "tutorial.assets.desc": "ارفع وأدر الأصول الإبداعية — الصور والفيديوهات والمستندات.",
+  "tutorial.newPost.title": "إنشاء محتوى",
+  "tutorial.newPost.desc": "ابدأ إنشاء المحتوى من هنا. اختر علامتك التجارية والمنصات وأسنده لعضو فريق.",
+  "tutorial.filters.title": "التصفية والتركيز",
+  "tutorial.filters.desc": "استخدم الفلاتر للتركيز على علامات أو منصات أو أعضاء فريق محددين.",
+  
+  "login.title": "سمايا للتسويق",
+  "login.subtitle": "سجل دخولك للمتابعة",
+  "login.forgotPassword": "نسيت كلمة المرور؟",
+  "login.defaultCreds": "بيانات الدخول الافتراضية:",
+  
+  "profile.completeYourProfile": "أكمل ملفك الشخصي",
+  "profile.completeDesc": "يرجى إكمال ملفك الشخصي للوصول إلى جميع الميزات ومساعدة فريقك في العثور عليك.",
+  "profile.completeProfileBtn": "إكمال الملف",
+  "profile.later": "لاحقاً"
+}
diff --git a/client/src/i18n/en.json b/client/src/i18n/en.json
new file mode 100644
index 0000000..727958a
--- /dev/null
+++ b/client/src/i18n/en.json
@@ -0,0 +1,239 @@
+{
+  "app.name": "Samaya",
+  "app.subtitle": "Marketing Hub",
+  "nav.dashboard": "Dashboard",
+  "nav.campaigns": "Campaigns",
+  "nav.finance": "Finance & ROI",
+  "nav.posts": "Post Production",
+  "nav.assets": "Assets",
+  "nav.projects": "Projects",
+  "nav.tasks": "Tasks",
+  "nav.team": "Team",
+  "nav.settings": "Settings",
+  "nav.users": "Users",
+  "nav.logout": "Logout",
+  "nav.collapse": "Collapse",
+  
+  "common.save": "Save",
+  "common.cancel": "Cancel",
+  "common.delete": "Delete",
+  "common.edit": "Edit",
+  "common.create": "Create",
+  "common.search": "Search...",
+  "common.filter": "Filter",
+  "common.all": "All",
+  "common.noResults": "No results",
+  "common.loading": "Loading...",
+  "common.unassigned": "Unassigned",
+  "common.required": "Required",
+  
+  "auth.login": "Sign In",
+  "auth.email": "Email",
+  "auth.password": "Password",
+  "auth.loginBtn": "Sign In",
+  "auth.signingIn": "Signing in...",
+  
+  "dashboard.title": "Dashboard",
+  "dashboard.welcomeBack": "Welcome back",
+  "dashboard.happeningToday": "Here's what's happening with your marketing today.",
+  "dashboard.totalPosts": "Total Posts",
+  "dashboard.published": "published",
+  "dashboard.activeCampaigns": "Active Campaigns",
+  "dashboard.total": "total",
+  "dashboard.budgetSpent": "Budget Spent",
+  "dashboard.of": "of",
+  "dashboard.noBudget": "No budget yet",
+  "dashboard.overdueTasks": "Overdue Tasks",
+  "dashboard.needsAttention": "Needs attention",
+  "dashboard.allOnTrack": "All on track",
+  "dashboard.budgetOverview": "Budget Overview",
+  "dashboard.details": "Details",
+  "dashboard.noBudgetRecorded": "No budget recorded yet.",
+  "dashboard.addBudget": "Add budget",
+  "dashboard.spent": "spent",
+  "dashboard.received": "received",
+  "dashboard.remaining": "Remaining",
+  "dashboard.revenue": "Revenue",
+  "dashboard.roi": "ROI",
+  "dashboard.recentPosts": "Recent Posts",
+  "dashboard.viewAll": "View all",
+  "dashboard.sar": "SAR",
+  "dashboard.noPostsYet": "No posts yet. Create your first post!",
+  "dashboard.upcomingDeadlines": "Upcoming Deadlines",
+  "dashboard.noUpcomingDeadlines": "No upcoming deadlines this week. 🎉",
+  "dashboard.loadingHub": "Loading Samaya Marketing Hub...",
+  
+  "posts.title": "Post Production",
+  "posts.newPost": "New Post",
+  "posts.editPost": "Edit Post",
+  "posts.createPost": "Create Post",
+  "posts.saveChanges": "Save Changes",
+  "posts.postTitle": "Title",
+  "posts.description": "Description",
+  "posts.brand": "Brand",
+  "posts.platforms": "Platforms",
+  "posts.status": "Status",
+  "posts.assignTo": "Assign To",
+  "posts.scheduledDate": "Scheduled Date",
+  "posts.notes": "Notes",
+  "posts.campaign": "Campaign",
+  "posts.noCampaign": "No campaign",
+  "posts.publicationLinks": "Publication Links",
+  "posts.attachments": "Attachments",
+  "posts.uploadFiles": "Click or drag files to upload",
+  "posts.dropFiles": "Drop files here",
+  "posts.maxSize": "Max 50MB per file",
+  "posts.allBrands": "All Brands",
+  "posts.allPlatforms": "All Platforms",
+  "posts.allPeople": "All People",
+  "posts.searchPosts": "Search posts...",
+  "posts.deletePost": "Delete Post?",
+  "posts.deleteConfirm": "Are you sure you want to delete this post? This action cannot be undone.",
+  "posts.publishMissing": "Cannot publish: missing publication links for:",
+  "posts.publishRequired": "All publication links are required to publish",
+  "posts.noPostsFound": "No posts found",
+  "posts.selectBrand": "Select brand",
+  "posts.additionalNotes": "Additional notes",
+  "posts.uploading": "Uploading...",
+  "posts.deleteAttachment": "Delete attachment",
+  "posts.whatNeedsDone": "What needs to be done?",
+  "posts.optionalDetails": "Optional details...",
+  "posts.postTitlePlaceholder": "Post title",
+  "posts.postDescPlaceholder": "Post description...",
+  "posts.dropHere": "Drop here",
+  "posts.noPosts": "No posts",
+  "posts.sendToReview": "Send to Review",
+  "posts.approve": "Approve",
+  "posts.schedule": "Schedule",
+  "posts.publish": "Publish",
+  
+  "posts.status.draft": "Draft",
+  "posts.status.in_review": "In Review",
+  "posts.status.approved": "Approved",
+  "posts.status.scheduled": "Scheduled",
+  "posts.status.published": "Published",
+  
+  "tasks.title": "Tasks",
+  "tasks.newTask": "New Task",
+  "tasks.editTask": "Edit Task",
+  "tasks.createTask": "Create Task",
+  "tasks.saveChanges": "Save Changes",
+  "tasks.taskTitle": "Title",
+  "tasks.description": "Description",
+  "tasks.priority": "Priority",
+  "tasks.dueDate": "Due Date",
+  "tasks.assignTo": "Assign to",
+  "tasks.allTasks": "All Tasks",
+  "tasks.assignedToMe": "Assigned to Me",
+  "tasks.createdByMe": "Created by Me",
+  "tasks.byTeamMember": "By Team Member",
+  "tasks.noTasks": "No tasks yet",
+  "tasks.noMatch": "No tasks match this filter",
+  "tasks.createFirst": "Create a task to get started",
+  "tasks.tryFilter": "Try a different filter",
+  "tasks.deleteTask": "Delete Task?",
+  "tasks.deleteConfirm": "Are you sure you want to delete this task? This action cannot be undone.",
+  "tasks.todo": "To Do",
+  "tasks.in_progress": "In Progress",
+  "tasks.done": "Done",
+  "tasks.start": "Start",
+  "tasks.complete": "Complete",
+  "tasks.from": "From:",
+  "tasks.assignedTo": "Assigned to:",
+  "tasks.task": "task",
+  "tasks.tasks": "tasks",
+  "tasks.of": "of",
+  
+  "tasks.priority.low": "Low",
+  "tasks.priority.medium": "Medium",
+  "tasks.priority.high": "High",
+  "tasks.priority.urgent": "Urgent",
+  
+  "team.title": "Team",
+  "team.members": "Team Members",
+  "team.addMember": "Add Member",
+  "team.newMember": "New Team Member",
+  "team.editMember": "Edit Team Member",
+  "team.myProfile": "My Profile",
+  "team.editProfile": "Edit My Profile",
+  "team.name": "Name",
+  "team.email": "Email",
+  "team.password": "Password",
+  "team.teamRole": "Team Role",
+  "team.phone": "Phone",
+  "team.brands": "Brands",
+  "team.brandsHelp": "Comma-separated brand names",
+  "team.removeMember": "Remove Team Member?",
+  "team.removeConfirm": "Are you sure you want to remove {name}? This action cannot be undone.",
+  "team.noMembers": "No team members",
+  "team.backToTeam": "Back to Team",
+  "team.totalTasks": "Total Tasks",
+  "team.saveProfile": "Save Profile",
+  "team.saveChanges": "Save Changes",
+  "team.member": "team member",
+  "team.membersPlural": "team members",
+  "team.fullName": "Full name",
+  "team.defaultPassword": "Default: changeme123",
+  "team.optional": "(optional)",
+  "team.fixedRole": "Fixed role for managers",
+  "team.remove": "Remove",
+  "team.noTasks": "No tasks",
+  "team.toDo": "To Do",
+  "team.inProgress": "In Progress",
+  
+  "campaigns.title": "Campaigns",
+  "campaigns.newCampaign": "New Campaign",
+  "campaigns.noCampaigns": "No campaigns",
+  
+  "assets.title": "Assets",
+  "assets.upload": "Upload",
+  "assets.noAssets": "No assets",
+  
+  "settings.title": "Settings",
+  "settings.language": "Language",
+  "settings.english": "English",
+  "settings.arabic": "Arabic",
+  "settings.restartTutorial": "Restart Tutorial",
+  "settings.tutorialDesc": "Need a refresher? Restart the interactive tutorial to learn about all the features of the Samaya Marketing Hub.",
+  "settings.general": "General",
+  "settings.onboardingTutorial": "Onboarding Tutorial",
+  "settings.tutorialRestarted": "Tutorial Restarted!",
+  "settings.restarting": "Restarting...",
+  "settings.reloadingPage": "Reloading page to start tutorial...",
+  "settings.moreComingSoon": "More Settings Coming Soon",
+  "settings.additionalSettings": "Additional settings for notifications, display preferences, and more will be added here.",
+  "settings.preferences": "Manage your preferences and app settings",
+  
+  "tutorial.skip": "Skip Tutorial",
+  "tutorial.next": "Next",
+  "tutorial.prev": "Back",
+  "tutorial.finish": "Finish",
+  "tutorial.of": "of",
+  "tutorial.step": "Step",
+  "tutorial.dashboard.title": "Dashboard",
+  "tutorial.dashboard.desc": "Your command center. See campaign performance, task progress, and team activity at a glance.",
+  "tutorial.campaigns.title": "Campaigns",
+  "tutorial.campaigns.desc": "Plan and manage marketing campaigns across all brands and platforms.",
+  "tutorial.posts.title": "Post Production",
+  "tutorial.posts.desc": "Create, review, and publish content. Drag posts through your workflow pipeline.",
+  "tutorial.tasks.title": "Tasks",
+  "tutorial.tasks.desc": "Assign and track tasks. Filter by who assigned them or who they're assigned to.",
+  "tutorial.team.title": "Team",
+  "tutorial.team.desc": "Your team directory. Complete your profile and see who you're working with.",
+  "tutorial.assets.title": "Assets",
+  "tutorial.assets.desc": "Upload and manage creative assets — images, videos, and documents.",
+  "tutorial.newPost.title": "Create Content",
+  "tutorial.newPost.desc": "Start creating content here. Pick your brand, platforms, and assign it to a team member.",
+  "tutorial.filters.title": "Filter & Focus",
+  "tutorial.filters.desc": "Use filters to focus on specific brands, platforms, or team members.",
+  
+  "login.title": "Samaya Marketing",
+  "login.subtitle": "Sign in to continue",
+  "login.forgotPassword": "Forgot password?",
+  "login.defaultCreds": "Default credentials:",
+  
+  "profile.completeYourProfile": "Complete Your Profile",
+  "profile.completeDesc": "Please complete your profile to access all features and help your team find you.",
+  "profile.completeProfileBtn": "Complete Profile",
+  "profile.later": "Later"
+}
diff --git a/client/src/index.css b/client/src/index.css
new file mode 100644
index 0000000..2d4f4fc
--- /dev/null
+++ b/client/src/index.css
@@ -0,0 +1,219 @@
+@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Sans+Arabic:wght@300;400;500;600;700&family=Inter:wght@300;400;500;600;700&display=swap');
+@import "tailwindcss";
+
+@theme {
+  --font-sans: 'Inter', 'IBM Plex Sans Arabic', system-ui, -apple-system, sans-serif;
+  --color-sidebar: #0f172a;
+  --color-sidebar-hover: #1e293b;
+  --color-sidebar-active: #020617;
+  --color-brand-primary: #4f46e5;
+  --color-brand-primary-light: #6366f1;
+  --color-brand-secondary: #db2777;
+  --color-brand-tertiary: #f59e0b;
+  --color-brand-quaternary: #059669;
+  --color-surface: #ffffff;
+  --color-surface-secondary: #f9fafb;
+  --color-surface-tertiary: #f3f4f6;
+  --color-border: #e5e7eb;
+  --color-border-light: #f3f4f6;
+  --color-text-primary: #0f172a;
+  --color-text-secondary: #475569;
+  --color-text-tertiary: #94a3b8;
+  --color-text-on-dark: #f8fafc;
+  --color-text-on-dark-muted: #94a3b8;
+  --color-status-draft: #9ca3af;
+  --color-status-in-review: #f59e0b;
+  --color-status-approved: #3b82f6;
+  --color-status-scheduled: #8b5cf6;
+  --color-status-published: #059669;
+  --color-status-rejected: #dc2626;
+  --color-status-todo: #9ca3af;
+  --color-status-in-progress: #3b82f6;
+  --color-status-done: #059669;
+  --color-status-active: #059669;
+  --color-status-paused: #f59e0b;
+  --color-status-completed: #3b82f6;
+  --color-status-cancelled: #dc2626;
+}
+
+/* Custom scrollbar */
+::-webkit-scrollbar {
+  width: 6px;
+  height: 6px;
+}
+::-webkit-scrollbar-track {
+  background: transparent;
+}
+::-webkit-scrollbar-thumb {
+  background: #cbd5e1;
+  border-radius: 6px;
+}
+::-webkit-scrollbar-thumb:hover {
+  background: #94a3b8;
+}
+
+/* Smooth transitions */
+* {
+  transition-property: background-color, border-color, color, opacity, box-shadow, transform;
+  transition-duration: 200ms;
+  transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
+}
+
+/* Arabic text support */
+[dir="rtl"] {
+  font-family: 'IBM Plex Sans Arabic', 'Inter', system-ui, sans-serif;
+}
+
+/* Auto-detect text direction in inputs for mixed Arabic/English content */
+input[type="text"],
+input[type="search"],
+input[type="url"],
+input[type="email"],
+textarea {
+  unicode-bidi: plaintext;
+}
+
+/* Ensure text content areas handle Arabic properly */
+.line-clamp-2, .truncate, h1, h2, h3, h4, h5, p, span, label {
+  unicode-bidi: plaintext;
+}
+
+/* RTL-aware sidebar positioning */
+[dir="rtl"] .sidebar {
+  right: 0;
+  left: auto;
+}
+
+[dir="ltr"] .sidebar {
+  left: 0;
+  right: auto;
+}
+
+/* RTL-aware main content margin */
+[dir="rtl"] .main-content-margin {
+  margin-right: 260px;
+  margin-left: 0;
+}
+
+[dir="ltr"] .main-content-margin {
+  margin-left: 260px;
+  margin-right: 0;
+}
+
+[dir="rtl"] .main-content-margin-collapsed {
+  margin-right: 68px;
+  margin-left: 0;
+}
+
+[dir="ltr"] .main-content-margin-collapsed {
+  margin-left: 68px;
+  margin-right: 0;
+}
+
+/* Enhanced sidebar with gradient */
+.sidebar {
+  background: linear-gradient(180deg, #0f172a 0%, #020617 100%);
+  box-shadow: 2px 0 12px rgba(0, 0, 0, 0.08);
+}
+
+/* Animation keyframes */
+@keyframes fadeIn {
+  from { opacity: 0; transform: translateY(8px); }
+  to { opacity: 1; transform: translateY(0); }
+}
+
+@keyframes slideIn {
+  from { opacity: 0; transform: translateX(-12px); }
+  to { opacity: 1; transform: translateX(0); }
+}
+
+@keyframes scaleIn {
+  from { opacity: 0; transform: scale(0.95); }
+  to { opacity: 1; transform: scale(1); }
+}
+
+@keyframes shimmer {
+  0% { background-position: -200% 0; }
+  100% { background-position: 200% 0; }
+}
+
+.animate-fade-in {
+  animation: fadeIn 0.3s ease-out forwards;
+}
+
+.animate-slide-in {
+  animation: slideIn 0.3s ease-out forwards;
+}
+
+.animate-scale-in {
+  animation: scaleIn 0.2s ease-out forwards;
+}
+
+/* Stagger children */
+.stagger-children > * {
+  opacity: 0;
+  animation: fadeIn 0.3s ease-out forwards;
+}
+.stagger-children > *:nth-child(1) { animation-delay: 0ms; }
+.stagger-children > *:nth-child(2) { animation-delay: 50ms; }
+.stagger-children > *:nth-child(3) { animation-delay: 100ms; }
+.stagger-children > *:nth-child(4) { animation-delay: 150ms; }
+.stagger-children > *:nth-child(5) { animation-delay: 200ms; }
+.stagger-children > *:nth-child(6) { animation-delay: 250ms; }
+.stagger-children > *:nth-child(7) { animation-delay: 300ms; }
+.stagger-children > *:nth-child(8) { animation-delay: 350ms; }
+
+/* Card hover effect - smooth and elegant */
+.card-hover {
+  position: relative;
+  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
+  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05), 0 1px 2px rgba(0, 0, 0, 0.06);
+}
+.card-hover:hover {
+  transform: translateY(-3px);
+  box-shadow: 0 12px 28px -6px rgba(0, 0, 0, 0.12), 0 6px 16px -8px rgba(0, 0, 0, 0.08);
+}
+
+/* Stat card accents - subtle colored top borders */
+.stat-card {
+  position: relative;
+  overflow: hidden;
+}
+.stat-card::before {
+  content: '';
+  position: absolute;
+  top: 0;
+  left: 0;
+  right: 0;
+  height: 3px;
+  background: linear-gradient(90deg, var(--color-brand-primary), var(--color-brand-primary-light));
+  opacity: 0;
+  transition: opacity 0.3s ease;
+}
+.stat-card:hover::before {
+  opacity: 1;
+}
+
+/* Refined button styles */
+button {
+  border-radius: 0.625rem;
+  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
+}
+button:hover:not(:disabled) {
+  transform: translateY(-1px);
+  box-shadow: 0 4px 12px -2px rgba(0, 0, 0, 0.12);
+}
+button:active:not(:disabled) {
+  transform: translateY(0);
+}
+
+/* Kanban column */
+.kanban-column {
+  min-height: 200px;
+}
+
+/* Calendar grid */
+.calendar-grid {
+  display: grid;
+  grid-template-columns: repeat(7, 1fr);
+}
diff --git a/client/src/main.jsx b/client/src/main.jsx
new file mode 100644
index 0000000..b15cdd6
--- /dev/null
+++ b/client/src/main.jsx
@@ -0,0 +1,13 @@
+import React from 'react'
+import ReactDOM from 'react-dom/client'
+import { BrowserRouter } from 'react-router-dom'
+import App from './App'
+import './index.css'
+
+ReactDOM.createRoot(document.getElementById('root')).render(
+  <React.StrictMode>
+    <BrowserRouter>
+      <App />
+    </BrowserRouter>
+  </React.StrictMode>,
+)
diff --git a/client/src/pages/Assets.jsx b/client/src/pages/Assets.jsx
new file mode 100644
index 0000000..feeb216
--- /dev/null
+++ b/client/src/pages/Assets.jsx
@@ -0,0 +1,356 @@
+import { useState, useEffect, useRef } from 'react'
+import { Plus, Upload, Search, FolderOpen, ChevronRight, Grid3X3, X } from 'lucide-react'
+import { api } from '../utils/api'
+import AssetCard from '../components/AssetCard'
+import Modal from '../components/Modal'
+
+export default function Assets() {
+  const [assets, setAssets] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [filters, setFilters] = useState({ brand: '', tag: '', folder: '', search: '' })
+  const [showUpload, setShowUpload] = useState(false)
+  const [uploading, setUploading] = useState(false)
+  const [uploadProgress, setUploadProgress] = useState(0)
+  const [dragOver, setDragOver] = useState(false)
+  const [selectedAsset, setSelectedAsset] = useState(null)
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+  const [assetToDelete, setAssetToDelete] = useState(null)
+  const fileRef = useRef(null)
+
+  useEffect(() => { loadAssets() }, [])
+
+  const loadAssets = async () => {
+    try {
+      const res = await api.get('/assets')
+      const assetsData = res.data || res || []
+      // Map assets to include URL for thumbnails
+      const assetsWithUrls = assetsData.map(asset => ({
+        ...asset,
+        _id: asset.id,
+        name: asset.original_name || asset.filename,
+        type: asset.mime_type?.startsWith('image') ? 'image' :
+              asset.mime_type?.startsWith('video') ? 'video' :
+              asset.mime_type?.startsWith('audio') ? 'audio' : 'document',
+        url: `/api/uploads/${asset.filename}`,
+        createdAt: asset.created_at,
+        fileType: asset.mime_type?.split('/')[1]?.toUpperCase() || 'FILE',
+      }))
+      setAssets(assetsWithUrls)
+    } catch (err) {
+      console.error('Failed to load assets:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleUpload = async (files) => {
+    if (!files || files.length === 0) return
+    setUploading(true)
+    setUploadProgress(0)
+    
+    try {
+      for (let i = 0; i < files.length; i++) {
+        const file = files[i]
+        const formData = new FormData()
+        formData.append('file', file)
+        formData.append('folder', 'general')
+        formData.append('brand_id', '')
+        formData.append('uploaded_by', '')
+        
+        // Use XMLHttpRequest to track upload progress
+        await new Promise((resolve, reject) => {
+          const xhr = new XMLHttpRequest()
+          
+          xhr.upload.addEventListener('progress', (e) => {
+            if (e.lengthComputable) {
+              const fileProgress = (e.loaded / e.total) * 100
+              const totalProgress = ((i + fileProgress / 100) / files.length) * 100
+              setUploadProgress(Math.round(totalProgress))
+            }
+          })
+          
+          xhr.addEventListener('load', () => {
+            if (xhr.status >= 200 && xhr.status < 300) {
+              resolve(JSON.parse(xhr.responseText))
+            } else {
+              reject(new Error(`Upload failed with status ${xhr.status}`))
+            }
+          })
+          
+          xhr.addEventListener('error', () => reject(new Error('Network error')))
+          
+          xhr.open('POST', '/api/assets/upload')
+          xhr.send(formData)
+        })
+      }
+      
+      loadAssets()
+      setShowUpload(false)
+      setUploadProgress(0)
+    } catch (err) {
+      console.error('Upload failed:', err)
+      alert('Upload failed: ' + err.message)
+    } finally {
+      setUploading(false)
+    }
+  }
+
+  const handleDeleteAsset = async (asset) => {
+    setAssetToDelete(asset)
+    setShowDeleteConfirm(true)
+  }
+
+  const confirmDeleteAsset = async () => {
+    if (!assetToDelete) return
+    try {
+      await api.delete(`/assets/${assetToDelete.id || assetToDelete._id}`)
+      setSelectedAsset(null)
+      setAssetToDelete(null)
+      loadAssets()
+    } catch (err) {
+      console.error('Delete failed:', err)
+      alert('Failed to delete asset')
+    }
+  }
+
+  const handleDrop = (e) => {
+    e.preventDefault()
+    setDragOver(false)
+    handleUpload(e.dataTransfer.files)
+  }
+
+  // Get unique values for filters
+  const brands = [...new Set(assets.map(a => a.brand).filter(Boolean))]
+  const allTags = [...new Set(assets.flatMap(a => a.tags || []))]
+  const folders = [...new Set(assets.map(a => a.folder).filter(Boolean))]
+
+  const filteredAssets = assets.filter(a => {
+    if (filters.brand && a.brand !== filters.brand) return false
+    if (filters.tag && !(a.tags || []).includes(filters.tag)) return false
+    if (filters.folder && a.folder !== filters.folder) return false
+    if (filters.search && !a.name?.toLowerCase().includes(filters.search.toLowerCase())) return false
+    return true
+  })
+
+  if (loading) {
+    return (
+      <div className="animate-pulse">
+        <div className="h-12 bg-surface-tertiary rounded-xl mb-4"></div>
+        <div className="grid grid-cols-2 md:grid-cols-4 lg:grid-cols-5 gap-4">
+          {[...Array(10)].map((_, i) => (
+            <div key={i} className="aspect-square bg-surface-tertiary rounded-xl"></div>
+          ))}
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-4 animate-fade-in">
+      {/* Toolbar */}
+      <div className="flex flex-wrap items-center gap-3">
+        <div className="relative flex-1 min-w-[200px] max-w-md">
+          <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-text-tertiary" />
+          <input
+            type="text"
+            placeholder="Search assets..."
+            value={filters.search}
+            onChange={e => setFilters(f => ({ ...f, search: e.target.value }))}
+            className="w-full pl-10 pr-4 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary bg-white"
+          />
+        </div>
+
+        <select
+          value={filters.brand}
+          onChange={e => setFilters(f => ({ ...f, brand: e.target.value }))}
+          className="text-sm border border-border rounded-lg px-3 py-2 bg-white text-text-secondary focus:outline-none"
+        >
+          <option value="">All Brands</option>
+          {brands.map(b => <option key={b} value={b}>{b}</option>)}
+        </select>
+
+        <select
+          value={filters.tag}
+          onChange={e => setFilters(f => ({ ...f, tag: e.target.value }))}
+          className="text-sm border border-border rounded-lg px-3 py-2 bg-white text-text-secondary focus:outline-none"
+        >
+          <option value="">All Tags</option>
+          {allTags.map(t => <option key={t} value={t}>{t}</option>)}
+        </select>
+
+        <button
+          onClick={() => setShowUpload(true)}
+          className="flex items-center gap-2 px-4 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm ml-auto"
+        >
+          <Upload className="w-4 h-4" />
+          Upload
+        </button>
+      </div>
+
+      {/* Folder breadcrumbs */}
+      {folders.length > 0 && (
+        <div className="flex items-center gap-2 flex-wrap">
+          <button
+            onClick={() => setFilters(f => ({ ...f, folder: '' }))}
+            className={`flex items-center gap-1.5 text-sm px-3 py-1.5 rounded-lg transition-colors ${
+              !filters.folder ? 'bg-brand-primary/10 text-brand-primary font-medium' : 'text-text-secondary hover:bg-surface-tertiary'
+            }`}
+          >
+            <FolderOpen className="w-4 h-4" />
+            All
+          </button>
+          {folders.map(folder => (
+            <button
+              key={folder}
+              onClick={() => setFilters(f => ({ ...f, folder }))}
+              className={`flex items-center gap-1.5 text-sm px-3 py-1.5 rounded-lg transition-colors ${
+                filters.folder === folder ? 'bg-brand-primary/10 text-brand-primary font-medium' : 'text-text-secondary hover:bg-surface-tertiary'
+              }`}
+            >
+              <FolderOpen className="w-4 h-4" />
+              {folder}
+            </button>
+          ))}
+        </div>
+      )}
+
+      {/* Asset grid */}
+      {filteredAssets.length === 0 ? (
+        <div className="py-20 text-center">
+          <Grid3X3 className="w-12 h-12 text-text-tertiary mx-auto mb-3" />
+          <p className="text-text-secondary font-medium">No assets found</p>
+          <p className="text-sm text-text-tertiary mt-1">Upload your first asset to get started</p>
+        </div>
+      ) : (
+        <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-4 xl:grid-cols-5 gap-4">
+          {filteredAssets.map(asset => (
+            <div key={asset._id || asset.id}>
+              <AssetCard asset={asset} onClick={setSelectedAsset} />
+            </div>
+          ))}
+        </div>
+      )}
+
+      {/* Upload Modal */}
+      <Modal isOpen={showUpload} onClose={() => !uploading && setShowUpload(false)} title="Upload Assets" size="md">
+        <div
+          onDragOver={(e) => { e.preventDefault(); setDragOver(true) }}
+          onDragLeave={() => setDragOver(false)}
+          onDrop={handleDrop}
+          onClick={() => !uploading && fileRef.current?.click()}
+          className={`border-2 border-dashed rounded-xl p-12 text-center transition-colors ${
+            uploading ? 'cursor-not-allowed opacity-60' : 'cursor-pointer'
+          } ${
+            dragOver ? 'border-brand-primary bg-brand-primary/5' : 'border-border hover:border-brand-primary/50'
+          }`}
+        >
+          <Upload className={`w-10 h-10 mx-auto mb-3 ${uploading ? 'animate-pulse' : ''} ${dragOver ? 'text-brand-primary' : 'text-text-tertiary'}`} />
+          <p className="text-sm font-medium text-text-primary">
+            {uploading ? `Uploading... ${uploadProgress}%` : 'Drop files here or click to browse'}
+          </p>
+          <p className="text-xs text-text-tertiary mt-1">
+            Images, videos, documents up to 50MB
+          </p>
+          {uploading && (
+            <div className="mt-4 w-full bg-surface-tertiary rounded-full h-2 overflow-hidden">
+              <div 
+                className="h-full bg-brand-primary transition-all duration-300"
+                style={{ width: `${uploadProgress}%` }}
+              />
+            </div>
+          )}
+          <input
+            ref={fileRef}
+            type="file"
+            multiple
+            disabled={uploading}
+            className="hidden"
+            onChange={e => handleUpload(e.target.files)}
+          />
+        </div>
+      </Modal>
+
+      {/* Asset detail modal */}
+      <Modal
+        isOpen={!!selectedAsset}
+        onClose={() => setSelectedAsset(null)}
+        title={selectedAsset?.name || 'Asset Details'}
+        size="lg"
+      >
+        {selectedAsset && (
+          <div className="space-y-4">
+            {selectedAsset.type === 'image' && selectedAsset.url && (
+              <div className="rounded-lg overflow-hidden bg-surface-tertiary">
+                <img src={selectedAsset.url} alt={selectedAsset.name} className="w-full max-h-[400px] object-contain" />
+              </div>
+            )}
+            <div className="grid grid-cols-2 gap-4 text-sm">
+              <div>
+                <p className="text-text-tertiary">Type</p>
+                <p className="font-medium text-text-primary capitalize">{selectedAsset.type}</p>
+              </div>
+              <div>
+                <p className="text-text-tertiary">Size</p>
+                <p className="font-medium text-text-primary">{selectedAsset.size ? `${(selectedAsset.size / 1024 / 1024).toFixed(2)} MB` : '—'}</p>
+              </div>
+              {selectedAsset.brand_name && (
+                <div>
+                  <p className="text-text-tertiary">Brand</p>
+                  <p className="font-medium text-text-primary">{selectedAsset.brand_name}</p>
+                </div>
+              )}
+              {selectedAsset.folder && (
+                <div>
+                  <p className="text-text-tertiary">Folder</p>
+                  <p className="font-medium text-text-primary">{selectedAsset.folder}</p>
+                </div>
+              )}
+            </div>
+            {selectedAsset.tags && selectedAsset.tags.length > 0 && (
+              <div>
+                <p className="text-sm text-text-tertiary mb-2">Tags</p>
+                <div className="flex flex-wrap gap-2">
+                  {selectedAsset.tags.map(tag => (
+                    <span key={tag} className="text-xs px-2 py-1 rounded-full bg-surface-tertiary text-text-secondary">
+                      {tag}
+                    </span>
+                  ))}
+                </div>
+              </div>
+            )}
+            <div className="flex items-center gap-3 pt-4 border-t border-border">
+              <button
+                onClick={() => handleDeleteAsset(selectedAsset)}
+                className="px-4 py-2 text-sm font-medium text-red-600 hover:bg-red-50 rounded-lg"
+              >
+                Delete Asset
+              </button>
+              <a
+                href={selectedAsset.url}
+                download={selectedAsset.name}
+                target="_blank"
+                rel="noopener noreferrer"
+                className="ml-auto px-4 py-2 text-sm font-medium bg-brand-primary text-white rounded-lg hover:bg-brand-primary-light"
+              >
+                Download
+              </a>
+            </div>
+          </div>
+        )}
+      </Modal>
+
+      {/* Delete Asset Confirmation */}
+      <Modal
+        isOpen={showDeleteConfirm}
+        onClose={() => { setShowDeleteConfirm(false); setAssetToDelete(null) }}
+        title="Delete Asset?"
+        isConfirm
+        danger
+        confirmText="Delete Asset"
+        onConfirm={confirmDeleteAsset}
+      >
+        Are you sure you want to delete this asset? This file will be permanently removed from the server. This action cannot be undone.
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/pages/CampaignDetail.jsx b/client/src/pages/CampaignDetail.jsx
new file mode 100644
index 0000000..db29f50
--- /dev/null
+++ b/client/src/pages/CampaignDetail.jsx
@@ -0,0 +1,565 @@
+import { useState, useEffect, useContext } from 'react'
+import { useParams, useNavigate } from 'react-router-dom'
+import { ArrowLeft, Plus, Edit2, Trash2, DollarSign, Eye, MousePointer, Target, TrendingUp, FileText, Megaphone, Search, Globe, Pencil } from 'lucide-react'
+import { format } from 'date-fns'
+import { AppContext } from '../App'
+import { useAuth } from '../contexts/AuthContext'
+import { api, PLATFORMS } from '../utils/api'
+import PlatformIcon, { PlatformIcons } from '../components/PlatformIcon'
+import StatusBadge from '../components/StatusBadge'
+import BrandBadge from '../components/BrandBadge'
+import Modal from '../components/Modal'
+
+const TRACK_TYPES = {
+  organic_social: { label: 'Organic Social', icon: Megaphone, color: 'text-green-600 bg-green-50', hasBudget: false },
+  paid_social: { label: 'Paid Social', icon: DollarSign, color: 'text-blue-600 bg-blue-50', hasBudget: true },
+  paid_search: { label: 'Paid Search (PPC)', icon: Search, color: 'text-amber-600 bg-amber-50', hasBudget: true },
+  seo_content: { label: 'SEO / Content', icon: Globe, color: 'text-purple-600 bg-purple-50', hasBudget: false },
+  production: { label: 'Production', icon: FileText, color: 'text-red-600 bg-red-50', hasBudget: true },
+}
+
+const TRACK_STATUSES = ['planned', 'active', 'paused', 'completed']
+
+const EMPTY_TRACK = {
+  name: '', type: 'organic_social', platform: '', budget_allocated: '', status: 'planned', notes: '',
+}
+
+const EMPTY_METRICS = {
+  budget_spent: '', revenue: '', impressions: '', clicks: '', conversions: '', notes: '',
+}
+
+function BudgetBar({ budget, spent }) {
+  if (!budget || budget <= 0) return null
+  const pct = Math.min((spent / budget) * 100, 100)
+  const color = pct > 90 ? 'bg-red-500' : pct > 70 ? 'bg-amber-500' : 'bg-emerald-500'
+  return (
+    <div className="w-full">
+      <div className="flex justify-between text-[10px] text-text-tertiary mb-0.5">
+        <span>{(spent || 0).toLocaleString()} spent</span>
+        <span>{budget.toLocaleString()} SAR</span>
+      </div>
+      <div className="h-2 bg-surface-tertiary rounded-full overflow-hidden">
+        <div className={`h-full ${color} rounded-full transition-all`} style={{ width: `${pct}%` }} />
+      </div>
+    </div>
+  )
+}
+
+function MetricBox({ label, value, icon: Icon, color = 'text-text-primary' }) {
+  return (
+    <div className="text-center">
+      <Icon className={`w-4 h-4 mx-auto mb-0.5 ${color}`} />
+      <div className={`text-base font-bold ${color}`}>{value ?? '—'}</div>
+      <div className="text-[10px] text-text-tertiary">{label}</div>
+    </div>
+  )
+}
+
+export default function CampaignDetail() {
+  const { id } = useParams()
+  const navigate = useNavigate()
+  const { brands } = useContext(AppContext)
+  const { permissions } = useAuth()
+  const canManage = permissions?.canEditCampaigns
+  const [campaign, setCampaign] = useState(null)
+  const [tracks, setTracks] = useState([])
+  const [posts, setPosts] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [showTrackModal, setShowTrackModal] = useState(false)
+  const [editingTrack, setEditingTrack] = useState(null)
+  const [trackForm, setTrackForm] = useState(EMPTY_TRACK)
+  const [showMetricsModal, setShowMetricsModal] = useState(false)
+  const [metricsTrack, setMetricsTrack] = useState(null)
+  const [metricsForm, setMetricsForm] = useState(EMPTY_METRICS)
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+  const [trackToDelete, setTrackToDelete] = useState(null)
+
+  useEffect(() => { loadAll() }, [id])
+
+  const loadAll = async () => {
+    try {
+      const [campRes, tracksRes, postsRes] = await Promise.all([
+        api.get(`/campaigns`),
+        api.get(`/campaigns/${id}/tracks`),
+        api.get(`/campaigns/${id}/posts`),
+      ])
+      const allCampaigns = campRes.data || campRes || []
+      const found = allCampaigns.find(c => String(c.id) === String(id) || String(c._id) === String(id))
+      setCampaign(found || null)
+      setTracks(tracksRes.data || tracksRes || [])
+      setPosts(postsRes.data || postsRes || [])
+    } catch (err) {
+      console.error('Failed to load campaign:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const saveTrack = async () => {
+    try {
+      const data = {
+        name: trackForm.name,
+        type: trackForm.type,
+        platform: trackForm.platform || null,
+        budget_allocated: trackForm.budget_allocated ? Number(trackForm.budget_allocated) : 0,
+        status: trackForm.status,
+        notes: trackForm.notes,
+      }
+      if (editingTrack) {
+        await api.patch(`/tracks/${editingTrack.id}`, data)
+      } else {
+        await api.post(`/campaigns/${id}/tracks`, data)
+      }
+      setShowTrackModal(false)
+      setEditingTrack(null)
+      setTrackForm(EMPTY_TRACK)
+      loadAll()
+    } catch (err) {
+      console.error('Save track failed:', err)
+    }
+  }
+
+  const deleteTrack = async (trackId) => {
+    setTrackToDelete(trackId)
+    setShowDeleteConfirm(true)
+  }
+
+  const confirmDeleteTrack = async () => {
+    if (!trackToDelete) return
+    await api.delete(`/tracks/${trackToDelete}`)
+    setTrackToDelete(null)
+    loadAll()
+  }
+
+  const saveMetrics = async () => {
+    try {
+      await api.patch(`/tracks/${metricsTrack.id}`, {
+        budget_spent: metricsForm.budget_spent ? Number(metricsForm.budget_spent) : 0,
+        revenue: metricsForm.revenue ? Number(metricsForm.revenue) : 0,
+        impressions: metricsForm.impressions ? Number(metricsForm.impressions) : 0,
+        clicks: metricsForm.clicks ? Number(metricsForm.clicks) : 0,
+        conversions: metricsForm.conversions ? Number(metricsForm.conversions) : 0,
+        notes: metricsForm.notes || '',
+      })
+      setShowMetricsModal(false)
+      setMetricsTrack(null)
+      loadAll()
+    } catch (err) {
+      console.error('Save metrics failed:', err)
+    }
+  }
+
+  const openEditTrack = (track) => {
+    setEditingTrack(track)
+    setTrackForm({
+      name: track.name || '',
+      type: track.type || 'organic_social',
+      platform: track.platform || '',
+      budget_allocated: track.budget_allocated || '',
+      status: track.status || 'planned',
+      notes: track.notes || '',
+    })
+    setShowTrackModal(true)
+  }
+
+  const openMetrics = (track) => {
+    setMetricsTrack(track)
+    setMetricsForm({
+      budget_spent: track.budget_spent || '',
+      revenue: track.revenue || '',
+      impressions: track.impressions || '',
+      clicks: track.clicks || '',
+      conversions: track.conversions || '',
+      notes: track.notes || '',
+    })
+    setShowMetricsModal(true)
+  }
+
+  if (loading) {
+    return <div className="animate-pulse"><div className="h-64 bg-surface-tertiary rounded-xl"></div></div>
+  }
+
+  if (!campaign) {
+    return (
+      <div className="text-center py-12 text-text-tertiary">
+        Campaign not found. <button onClick={() => navigate('/campaigns')} className="text-brand-primary underline">Go back</button>
+      </div>
+    )
+  }
+
+  // Aggregates from tracks
+  const totalAllocated = tracks.reduce((s, t) => s + (t.budget_allocated || 0), 0)
+  const totalSpent = tracks.reduce((s, t) => s + (t.budget_spent || 0), 0)
+  const totalImpressions = tracks.reduce((s, t) => s + (t.impressions || 0), 0)
+  const totalClicks = tracks.reduce((s, t) => s + (t.clicks || 0), 0)
+  const totalConversions = tracks.reduce((s, t) => s + (t.conversions || 0), 0)
+  const totalRevenue = tracks.reduce((s, t) => s + (t.revenue || 0), 0)
+
+  return (
+    <div className="space-y-6 animate-fade-in">
+      {/* Header */}
+      <div className="flex items-start gap-4">
+        <button onClick={() => navigate('/campaigns')} className="mt-1 p-1.5 hover:bg-surface-tertiary rounded-lg">
+          <ArrowLeft className="w-5 h-5 text-text-secondary" />
+        </button>
+        <div className="flex-1">
+          <div className="flex items-center gap-3 mb-1">
+            <h1 className="text-xl font-bold text-text-primary">{campaign.name}</h1>
+            <StatusBadge status={campaign.status} />
+            {campaign.brand_name && <BrandBadge brand={campaign.brand_name} />}
+          </div>
+          {campaign.description && <p className="text-sm text-text-secondary">{campaign.description}</p>}
+          <div className="flex items-center gap-4 mt-2 text-xs text-text-tertiary">
+            {campaign.start_date && campaign.end_date && (
+              <span>{format(new Date(campaign.start_date), 'MMM d')} – {format(new Date(campaign.end_date), 'MMM d, yyyy')}</span>
+            )}
+            {campaign.budget > 0 && <span>Budget: {campaign.budget.toLocaleString()} SAR</span>}
+          </div>
+        </div>
+      </div>
+
+      {/* Aggregate Metrics */}
+      {tracks.length > 0 && (
+        <div className="bg-white rounded-xl border border-border p-5">
+          <h3 className="text-xs uppercase tracking-wider text-text-tertiary font-medium mb-4">Campaign Totals (from tracks)</h3>
+          <div className="grid grid-cols-3 md:grid-cols-6 gap-4">
+            <MetricBox icon={DollarSign} label="Allocated" value={`${totalAllocated.toLocaleString()}`} color="text-blue-600" />
+            <MetricBox icon={TrendingUp} label="Spent" value={`${totalSpent.toLocaleString()}`} color="text-amber-600" />
+            <MetricBox icon={Eye} label="Impressions" value={totalImpressions.toLocaleString()} color="text-purple-600" />
+            <MetricBox icon={MousePointer} label="Clicks" value={totalClicks.toLocaleString()} color="text-green-600" />
+            <MetricBox icon={Target} label="Conversions" value={totalConversions.toLocaleString()} color="text-red-600" />
+            <MetricBox icon={DollarSign} label="Revenue" value={`${totalRevenue.toLocaleString()}`} color="text-emerald-600" />
+          </div>
+          {totalAllocated > 0 && (
+            <div className="mt-4">
+              <BudgetBar budget={totalAllocated} spent={totalSpent} />
+            </div>
+          )}
+        </div>
+      )}
+
+      {/* Tracks */}
+      <div className="bg-white rounded-xl border border-border overflow-hidden">
+        <div className="flex items-center justify-between px-5 py-4 border-b border-border">
+          <h3 className="font-semibold text-text-primary">Tracks</h3>
+          {canManage && (
+            <button
+              onClick={() => { setEditingTrack(null); setTrackForm(EMPTY_TRACK); setShowTrackModal(true) }}
+              className="flex items-center gap-1.5 px-3 py-1.5 bg-brand-primary text-white rounded-lg text-xs font-medium hover:bg-brand-primary-light"
+            >
+              <Plus className="w-3.5 h-3.5" /> Add Track
+            </button>
+          )}
+        </div>
+
+        {tracks.length === 0 ? (
+          <div className="py-12 text-center text-sm text-text-tertiary">
+            No tracks yet. Add organic, paid, or SEO tracks to organize this campaign.
+          </div>
+        ) : (
+          <div className="divide-y divide-border-light">
+            {tracks.map(track => {
+              const typeInfo = TRACK_TYPES[track.type] || TRACK_TYPES.organic_social
+              const TypeIcon = typeInfo.icon
+              const trackPosts = posts.filter(p => p.track_id === track.id)
+              return (
+                <div key={track.id} className="px-5 py-4">
+                  <div className="flex items-start gap-3">
+                    <div className={`p-2 rounded-lg ${typeInfo.color}`}>
+                      <TypeIcon className="w-4 h-4" />
+                    </div>
+                    <div className="flex-1 min-w-0">
+                      <div className="flex items-center gap-2 mb-0.5">
+                        <h4 className="text-sm font-semibold text-text-primary">
+                          {track.name || typeInfo.label}
+                        </h4>
+                        <span className="text-[10px] px-1.5 py-0.5 rounded bg-surface-tertiary text-text-tertiary">
+                          {typeInfo.label}
+                        </span>
+                        {track.platform && (
+                          <PlatformIcon platform={track.platform} size={16} />
+                        )}
+                        <StatusBadge status={track.status} size="xs" />
+                      </div>
+
+                      {/* Budget bar for paid tracks */}
+                      {track.budget_allocated > 0 && (
+                        <div className="w-48 mt-1.5">
+                          <BudgetBar budget={track.budget_allocated} spent={track.budget_spent || 0} />
+                        </div>
+                      )}
+
+                      {/* Quick metrics */}
+                      {(track.impressions > 0 || track.clicks > 0 || track.conversions > 0) && (
+                        <div className="flex items-center gap-3 mt-1.5 text-[10px] text-text-tertiary">
+                          {track.impressions > 0 && <span>👁 {track.impressions.toLocaleString()}</span>}
+                          {track.clicks > 0 && <span>🖱 {track.clicks.toLocaleString()}</span>}
+                          {track.conversions > 0 && <span>🎯 {track.conversions.toLocaleString()}</span>}
+                          {track.clicks > 0 && track.budget_spent > 0 && (
+                            <span>CPC: {(track.budget_spent / track.clicks).toFixed(2)} SAR</span>
+                          )}
+                          {track.impressions > 0 && track.clicks > 0 && (
+                            <span>CTR: {(track.clicks / track.impressions * 100).toFixed(2)}%</span>
+                          )}
+                        </div>
+                      )}
+
+                      {/* Linked posts count */}
+                      {trackPosts.length > 0 && (
+                        <div className="text-[10px] text-text-tertiary mt-1">
+                          📝 {trackPosts.length} post{trackPosts.length !== 1 ? 's' : ''} linked
+                        </div>
+                      )}
+
+                      {track.notes && (
+                        <p className="text-xs text-text-secondary mt-1 line-clamp-1">{track.notes}</p>
+                      )}
+                    </div>
+
+                    {/* Actions */}
+                    {canManage && (
+                      <div className="flex items-center gap-1 shrink-0">
+                        <button
+                          onClick={() => openMetrics(track)}
+                          title="Update metrics"
+                          className="p-1.5 hover:bg-surface-tertiary rounded-lg text-text-tertiary hover:text-brand-primary"
+                        >
+                          <TrendingUp className="w-4 h-4" />
+                        </button>
+                        <button
+                          onClick={() => openEditTrack(track)}
+                          title="Edit track"
+                          className="p-1.5 hover:bg-surface-tertiary rounded-lg text-text-tertiary hover:text-text-primary"
+                        >
+                          <Edit2 className="w-4 h-4" />
+                        </button>
+                        <button
+                          onClick={() => deleteTrack(track.id)}
+                          title="Delete track"
+                          className="p-1.5 hover:bg-red-50 rounded-lg text-text-tertiary hover:text-red-500"
+                        >
+                          <Trash2 className="w-4 h-4" />
+                        </button>
+                      </div>
+                    )}
+                  </div>
+                </div>
+              )
+            })}
+          </div>
+        )}
+      </div>
+
+      {/* Linked Posts */}
+      {posts.length > 0 && (
+        <div className="bg-white rounded-xl border border-border overflow-hidden">
+          <div className="px-5 py-4 border-b border-border">
+            <h3 className="font-semibold text-text-primary">Linked Posts ({posts.length})</h3>
+          </div>
+          <div className="divide-y divide-border-light">
+            {posts.map(post => (
+              <div key={post.id} className="flex items-center gap-3 px-5 py-3">
+                <div className="flex-1 min-w-0">
+                  <div className="flex items-center gap-2">
+                    <h4 className="text-sm font-medium text-text-primary">{post.title}</h4>
+                    <StatusBadge status={post.status} size="xs" />
+                  </div>
+                  <div className="flex items-center gap-2 mt-0.5 text-[10px] text-text-tertiary">
+                    {post.track_name && <span className="px-1.5 py-0.5 rounded bg-surface-tertiary">{post.track_name}</span>}
+                    {post.assigned_name && <span>→ {post.assigned_name}</span>}
+                    {post.platforms && post.platforms.length > 0 && (
+                      <PlatformIcons platforms={post.platforms} size={14} />
+                    )}
+                  </div>
+                </div>
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* Add/Edit Track Modal */}
+      <Modal
+        isOpen={showTrackModal}
+        onClose={() => { setShowTrackModal(false); setEditingTrack(null) }}
+        title={editingTrack ? 'Edit Track' : 'Add Track'}
+      >
+        <div className="space-y-4">
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Track Name</label>
+            <input
+              type="text"
+              value={trackForm.name}
+              onChange={e => setTrackForm(f => ({ ...f, name: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder="e.g., Instagram Paid Ads, Organic Wave, Google Search..."
+            />
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Type</label>
+              <select
+                value={trackForm.type}
+                onChange={e => setTrackForm(f => ({ ...f, type: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+              >
+                {Object.entries(TRACK_TYPES).map(([k, v]) => (
+                  <option key={k} value={k}>{v.label}</option>
+                ))}
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Platform</label>
+              <select
+                value={trackForm.platform}
+                onChange={e => setTrackForm(f => ({ ...f, platform: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+              >
+                <option value="">All / Multiple</option>
+                {Object.entries(PLATFORMS).map(([k, v]) => (
+                  <option key={k} value={k}>{v.label}</option>
+                ))}
+                <option value="google_ads">Google Ads</option>
+              </select>
+            </div>
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Budget Allocated (SAR)</label>
+              <input
+                type="number"
+                value={trackForm.budget_allocated}
+                onChange={e => setTrackForm(f => ({ ...f, budget_allocated: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+                placeholder="0 for free/organic"
+              />
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Status</label>
+              <select
+                value={trackForm.status}
+                onChange={e => setTrackForm(f => ({ ...f, status: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+              >
+                {TRACK_STATUSES.map(s => (
+                  <option key={s} value={s}>{s.charAt(0).toUpperCase() + s.slice(1)}</option>
+                ))}
+              </select>
+            </div>
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Notes</label>
+            <textarea
+              value={trackForm.notes}
+              onChange={e => setTrackForm(f => ({ ...f, notes: e.target.value }))}
+              rows={2}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none resize-none"
+              placeholder="Keywords, targeting details, content plan..."
+            />
+          </div>
+
+          <div className="flex justify-end gap-3 pt-4 border-t border-border">
+            <button onClick={() => setShowTrackModal(false)} className="px-4 py-2 text-sm text-text-secondary hover:bg-surface-tertiary rounded-lg">Cancel</button>
+            <button onClick={saveTrack} className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm">
+              {editingTrack ? 'Save' : 'Add Track'}
+            </button>
+          </div>
+        </div>
+      </Modal>
+
+      {/* Update Metrics Modal */}
+      <Modal
+        isOpen={showMetricsModal}
+        onClose={() => { setShowMetricsModal(false); setMetricsTrack(null) }}
+        title={`Update Metrics — ${metricsTrack?.name || ''}`}
+      >
+        <div className="space-y-4">
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Budget Spent (SAR)</label>
+              <input
+                type="number"
+                value={metricsForm.budget_spent}
+                onChange={e => setMetricsForm(f => ({ ...f, budget_spent: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+              />
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Revenue (SAR)</label>
+              <input
+                type="number"
+                value={metricsForm.revenue}
+                onChange={e => setMetricsForm(f => ({ ...f, revenue: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+              />
+            </div>
+          </div>
+
+          <div className="grid grid-cols-3 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Impressions</label>
+              <input
+                type="number"
+                value={metricsForm.impressions}
+                onChange={e => setMetricsForm(f => ({ ...f, impressions: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+              />
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Clicks</label>
+              <input
+                type="number"
+                value={metricsForm.clicks}
+                onChange={e => setMetricsForm(f => ({ ...f, clicks: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+              />
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Conversions</label>
+              <input
+                type="number"
+                value={metricsForm.conversions}
+                onChange={e => setMetricsForm(f => ({ ...f, conversions: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+              />
+            </div>
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Notes</label>
+            <textarea
+              value={metricsForm.notes}
+              onChange={e => setMetricsForm(f => ({ ...f, notes: e.target.value }))}
+              rows={2}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none resize-none"
+              placeholder="What's working, what to adjust..."
+            />
+          </div>
+
+          <div className="flex justify-end gap-3 pt-4 border-t border-border">
+            <button onClick={() => setShowMetricsModal(false)} className="px-4 py-2 text-sm text-text-secondary hover:bg-surface-tertiary rounded-lg">Cancel</button>
+            <button onClick={saveMetrics} className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm">
+              Save Metrics
+            </button>
+          </div>
+        </div>
+      </Modal>
+
+      {/* Delete Track Confirmation */}
+      <Modal
+        isOpen={showDeleteConfirm}
+        onClose={() => { setShowDeleteConfirm(false); setTrackToDelete(null) }}
+        title="Delete Track?"
+        isConfirm
+        danger
+        confirmText="Delete Track"
+        onConfirm={confirmDeleteTrack}
+      >
+        Are you sure you want to delete this campaign track? This action cannot be undone.
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/pages/Campaigns.jsx b/client/src/pages/Campaigns.jsx
new file mode 100644
index 0000000..3e32495
--- /dev/null
+++ b/client/src/pages/Campaigns.jsx
@@ -0,0 +1,637 @@
+import { useState, useEffect, useContext } from 'react'
+import { useNavigate } from 'react-router-dom'
+import { Plus, Search, TrendingUp, DollarSign, Eye, MousePointer, Target, BarChart3 } from 'lucide-react'
+import { format } from 'date-fns'
+import { AppContext } from '../App'
+import { useAuth } from '../contexts/AuthContext'
+import { api, PLATFORMS } from '../utils/api'
+import { PlatformIcons } from '../components/PlatformIcon'
+import CampaignCalendar from '../components/CampaignCalendar'
+import StatusBadge from '../components/StatusBadge'
+import BrandBadge from '../components/BrandBadge'
+import Modal from '../components/Modal'
+
+const EMPTY_CAMPAIGN = {
+  name: '', description: '', brand_id: '', status: 'planning',
+  start_date: '', end_date: '', budget: '', goals: '', platforms: [],
+  budget_spent: '', revenue: '', impressions: '', clicks: '', conversions: '', cost_per_click: '', notes: '',
+}
+
+function BudgetBar({ budget, spent }) {
+  if (!budget || budget <= 0) return null
+  const pct = Math.min((spent / budget) * 100, 100)
+  const color = pct > 90 ? 'bg-red-500' : pct > 70 ? 'bg-amber-500' : 'bg-emerald-500'
+  return (
+    <div className="w-full">
+      <div className="flex justify-between text-[10px] text-text-tertiary mb-0.5">
+        <span>{spent?.toLocaleString() || 0} SAR spent</span>
+        <span>{budget?.toLocaleString()} SAR</span>
+      </div>
+      <div className="h-1.5 bg-surface-tertiary rounded-full overflow-hidden">
+        <div className={`h-full ${color} rounded-full transition-all`} style={{ width: `${pct}%` }} />
+      </div>
+    </div>
+  )
+}
+
+function ROIBadge({ revenue, spent }) {
+  if (!spent || spent <= 0) return null
+  const roi = ((revenue - spent) / spent * 100).toFixed(0)
+  const color = roi >= 0 ? 'text-emerald-600 bg-emerald-50' : 'text-red-600 bg-red-50'
+  return (
+    <span className={`text-[10px] font-semibold px-1.5 py-0.5 rounded ${color}`}>
+      ROI {roi}%
+    </span>
+  )
+}
+
+function MetricCard({ icon: Icon, label, value, color = 'text-text-primary' }) {
+  return (
+    <div className="bg-surface-secondary rounded-lg p-3 text-center">
+      <Icon className={`w-4 h-4 mx-auto mb-1 ${color}`} />
+      <div className={`text-sm font-bold ${color}`}>{value || '—'}</div>
+      <div className="text-[10px] text-text-tertiary">{label}</div>
+    </div>
+  )
+}
+
+export default function Campaigns() {
+  const { brands } = useContext(AppContext)
+  const { permissions } = useAuth()
+  const navigate = useNavigate()
+  const [campaigns, setCampaigns] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [showModal, setShowModal] = useState(false)
+  const [editingCampaign, setEditingCampaign] = useState(null)
+  const [formData, setFormData] = useState(EMPTY_CAMPAIGN)
+  const [filters, setFilters] = useState({ brand: '', status: '' })
+  const [activeTab, setActiveTab] = useState('details') // details | performance
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+
+  useEffect(() => { loadCampaigns() }, [])
+
+  const loadCampaigns = async () => {
+    try {
+      const res = await api.get('/campaigns')
+      setCampaigns(res.data || res || [])
+    } catch (err) {
+      console.error('Failed to load campaigns:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleSave = async () => {
+    try {
+      const data = {
+        name: formData.name,
+        description: formData.description,
+        brand_id: formData.brand_id ? Number(formData.brand_id) : null,
+        status: formData.status,
+        start_date: formData.start_date,
+        end_date: formData.end_date,
+        budget: formData.budget ? Number(formData.budget) : null,
+        goals: formData.goals,
+        platforms: formData.platforms || [],
+        budget_spent: formData.budget_spent ? Number(formData.budget_spent) : 0,
+        revenue: formData.revenue ? Number(formData.revenue) : 0,
+        impressions: formData.impressions ? Number(formData.impressions) : 0,
+        clicks: formData.clicks ? Number(formData.clicks) : 0,
+        conversions: formData.conversions ? Number(formData.conversions) : 0,
+        cost_per_click: formData.cost_per_click ? Number(formData.cost_per_click) : 0,
+        notes: formData.notes || '',
+      }
+      if (editingCampaign) {
+        await api.patch(`/campaigns/${editingCampaign.id || editingCampaign._id}`, data)
+      } else {
+        await api.post('/campaigns', data)
+      }
+      setShowModal(false)
+      setEditingCampaign(null)
+      setFormData(EMPTY_CAMPAIGN)
+      loadCampaigns()
+    } catch (err) {
+      console.error('Save failed:', err)
+    }
+  }
+
+  const openEdit = (campaign) => {
+    setEditingCampaign(campaign)
+    setFormData({
+      name: campaign.name || '',
+      description: campaign.description || '',
+      brand_id: campaign.brandId || campaign.brand_id || '',
+      status: campaign.status || 'planning',
+      start_date: campaign.startDate ? new Date(campaign.startDate).toISOString().slice(0, 10) : '',
+      end_date: campaign.endDate ? new Date(campaign.endDate).toISOString().slice(0, 10) : '',
+      budget: campaign.budget || '',
+      goals: campaign.goals || '',
+      platforms: campaign.platforms || [],
+      budget_spent: campaign.budgetSpent || campaign.budget_spent || '',
+      revenue: campaign.revenue || '',
+      impressions: campaign.impressions || '',
+      clicks: campaign.clicks || '',
+      conversions: campaign.conversions || '',
+      cost_per_click: campaign.costPerClick || campaign.cost_per_click || '',
+      notes: campaign.notes || '',
+    })
+    setActiveTab('details')
+    setShowModal(true)
+  }
+
+  const openNew = () => {
+    setEditingCampaign(null)
+    setFormData(EMPTY_CAMPAIGN)
+    setActiveTab('details')
+    setShowModal(true)
+  }
+
+  const filtered = campaigns.filter(c => {
+    if (filters.brand && String(c.brandId || c.brand_id) !== filters.brand) return false
+    if (filters.status && c.status !== filters.status) return false
+    return true
+  })
+
+  // Aggregate stats
+  const totalBudget = filtered.reduce((sum, c) => sum + (c.budget || 0), 0)
+  const totalSpent = filtered.reduce((sum, c) => sum + (c.budgetSpent || c.budget_spent || 0), 0)
+  const totalImpressions = filtered.reduce((sum, c) => sum + (c.impressions || 0), 0)
+  const totalClicks = filtered.reduce((sum, c) => sum + (c.clicks || 0), 0)
+  const totalConversions = filtered.reduce((sum, c) => sum + (c.conversions || 0), 0)
+  const totalRevenue = filtered.reduce((sum, c) => sum + (c.revenue || 0), 0)
+
+  if (loading) {
+    return (
+      <div className="space-y-4 animate-pulse">
+        <div className="h-12 bg-surface-tertiary rounded-xl"></div>
+        <div className="h-[400px] bg-surface-tertiary rounded-xl"></div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-6 animate-fade-in">
+      {/* Summary Cards */}
+      {(totalBudget > 0 || totalSpent > 0) && (
+        <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-6 gap-3">
+          <div className="bg-white rounded-xl border border-border p-4">
+            <div className="flex items-center gap-2 mb-1">
+              <DollarSign className="w-4 h-4 text-blue-500" />
+              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Budget</span>
+            </div>
+            <div className="text-lg font-bold text-text-primary">{totalBudget.toLocaleString()}</div>
+            <div className="text-[10px] text-text-tertiary">SAR total</div>
+          </div>
+          <div className="bg-white rounded-xl border border-border p-4">
+            <div className="flex items-center gap-2 mb-1">
+              <TrendingUp className="w-4 h-4 text-amber-500" />
+              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Spent</span>
+            </div>
+            <div className="text-lg font-bold text-text-primary">{totalSpent.toLocaleString()}</div>
+            <div className="text-[10px] text-text-tertiary">SAR spent</div>
+          </div>
+          <div className="bg-white rounded-xl border border-border p-4">
+            <div className="flex items-center gap-2 mb-1">
+              <Eye className="w-4 h-4 text-purple-500" />
+              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Impressions</span>
+            </div>
+            <div className="text-lg font-bold text-text-primary">{totalImpressions.toLocaleString()}</div>
+          </div>
+          <div className="bg-white rounded-xl border border-border p-4">
+            <div className="flex items-center gap-2 mb-1">
+              <MousePointer className="w-4 h-4 text-green-500" />
+              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Clicks</span>
+            </div>
+            <div className="text-lg font-bold text-text-primary">{totalClicks.toLocaleString()}</div>
+          </div>
+          <div className="bg-white rounded-xl border border-border p-4">
+            <div className="flex items-center gap-2 mb-1">
+              <Target className="w-4 h-4 text-red-500" />
+              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Conversions</span>
+            </div>
+            <div className="text-lg font-bold text-text-primary">{totalConversions.toLocaleString()}</div>
+          </div>
+          <div className="bg-white rounded-xl border border-border p-4">
+            <div className="flex items-center gap-2 mb-1">
+              <BarChart3 className="w-4 h-4 text-emerald-500" />
+              <span className="text-[10px] uppercase tracking-wider text-text-tertiary font-medium">Revenue</span>
+            </div>
+            <div className="text-lg font-bold text-text-primary">{totalRevenue.toLocaleString()}</div>
+            <div className="text-[10px] text-text-tertiary">SAR</div>
+          </div>
+        </div>
+      )}
+
+      {/* Toolbar */}
+      <div className="flex flex-wrap items-center gap-3">
+        <select
+          value={filters.brand}
+          onChange={e => setFilters(f => ({ ...f, brand: e.target.value }))}
+          className="text-sm border border-border rounded-lg px-3 py-2 bg-white text-text-secondary focus:outline-none"
+        >
+          <option value="">All Brands</option>
+          {brands.map(b => <option key={b.id || b._id} value={b.id || b._id}>{b.name}</option>)}
+        </select>
+
+        <select
+          value={filters.status}
+          onChange={e => setFilters(f => ({ ...f, status: e.target.value }))}
+          className="text-sm border border-border rounded-lg px-3 py-2 bg-white text-text-secondary focus:outline-none"
+        >
+          <option value="">All Statuses</option>
+          <option value="planning">Planning</option>
+          <option value="active">Active</option>
+          <option value="paused">Paused</option>
+          <option value="completed">Completed</option>
+          <option value="cancelled">Cancelled</option>
+        </select>
+
+        {permissions?.canCreateCampaigns && (
+          <button
+            onClick={openNew}
+            className="flex items-center gap-2 px-4 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm ml-auto"
+          >
+            <Plus className="w-4 h-4" />
+            New Campaign
+          </button>
+        )}
+      </div>
+
+      {/* Calendar */}
+      <CampaignCalendar campaigns={filtered} />
+
+      {/* Campaign list */}
+      <div className="bg-white rounded-xl border border-border overflow-hidden">
+        <div className="px-5 py-4 border-b border-border">
+          <h3 className="font-semibold text-text-primary">All Campaigns</h3>
+        </div>
+        <div className="divide-y divide-border-light">
+          {filtered.length === 0 ? (
+            <div className="py-12 text-center text-sm text-text-tertiary">
+              No campaigns found
+            </div>
+          ) : (
+            filtered.map(campaign => {
+              const spent = campaign.budgetSpent || campaign.budget_spent || 0
+              const budget = campaign.budget || 0
+              return (
+                <div
+                  key={campaign.id || campaign._id}
+                  onClick={() => permissions?.canEditCampaigns ? navigate(`/campaigns/${campaign.id || campaign._id}`) : navigate(`/campaigns/${campaign.id || campaign._id}`)}
+                  className="flex items-center gap-4 px-5 py-4 hover:bg-surface-secondary cursor-pointer transition-colors"
+                >
+                  <div className="flex-1 min-w-0">
+                    <div className="flex items-center gap-2 mb-1">
+                      <h4 className="text-sm font-semibold text-text-primary">{campaign.name}</h4>
+                      {campaign.brandName && <BrandBadge brand={campaign.brandName} />}
+                      <ROIBadge revenue={campaign.revenue || 0} spent={spent} />
+                    </div>
+                    {campaign.description && (
+                      <p className="text-xs text-text-secondary line-clamp-1">{campaign.description}</p>
+                    )}
+                    <div className="flex items-center gap-3 mt-1.5">
+                      {campaign.platforms && campaign.platforms.length > 0 && (
+                        <PlatformIcons platforms={campaign.platforms} size={16} />
+                      )}
+                      {budget > 0 && (
+                        <div className="w-32">
+                          <BudgetBar budget={budget} spent={spent} />
+                        </div>
+                      )}
+                    </div>
+                    {/* Quick metrics row */}
+                    {(campaign.impressions > 0 || campaign.clicks > 0) && (
+                      <div className="flex items-center gap-3 mt-1.5 text-[10px] text-text-tertiary">
+                        {campaign.impressions > 0 && <span>👁 {campaign.impressions.toLocaleString()}</span>}
+                        {campaign.clicks > 0 && <span>🖱 {campaign.clicks.toLocaleString()}</span>}
+                        {campaign.conversions > 0 && <span>🎯 {campaign.conversions.toLocaleString()}</span>}
+                      </div>
+                    )}
+                  </div>
+                  <div className="text-right shrink-0">
+                    <StatusBadge status={campaign.status} size="xs" />
+                    <div className="text-xs text-text-tertiary mt-1">
+                      {campaign.startDate && campaign.endDate ? (
+                        <>
+                          {format(new Date(campaign.startDate), 'MMM d')} – {format(new Date(campaign.endDate), 'MMM d, yyyy')}
+                        </>
+                      ) : '—'}
+                    </div>
+                  </div>
+                </div>
+              )
+            })
+          )}
+        </div>
+      </div>
+
+      {/* Create/Edit Modal */}
+      <Modal
+        isOpen={showModal}
+        onClose={() => { setShowModal(false); setEditingCampaign(null) }}
+        title={editingCampaign ? 'Edit Campaign' : 'Create Campaign'}
+        size="lg"
+      >
+        <div className="space-y-4">
+          {/* Tabs */}
+          {editingCampaign && (
+            <div className="flex gap-1 p-1 bg-surface-tertiary rounded-lg">
+              <button
+                onClick={() => setActiveTab('details')}
+                className={`flex-1 px-3 py-1.5 text-sm font-medium rounded-md transition-colors ${
+                  activeTab === 'details' ? 'bg-white text-text-primary shadow-sm' : 'text-text-tertiary hover:text-text-secondary'
+                }`}
+              >
+                Details
+              </button>
+              <button
+                onClick={() => setActiveTab('performance')}
+                className={`flex-1 px-3 py-1.5 text-sm font-medium rounded-md transition-colors ${
+                  activeTab === 'performance' ? 'bg-white text-text-primary shadow-sm' : 'text-text-tertiary hover:text-text-secondary'
+                }`}
+              >
+                Performance & ROI
+              </button>
+            </div>
+          )}
+
+          {activeTab === 'details' ? (
+            <>
+              <div>
+                <label className="block text-sm font-medium text-text-primary mb-1">Name *</label>
+                <input
+                  type="text"
+                  value={formData.name}
+                  onChange={e => setFormData(f => ({ ...f, name: e.target.value }))}
+                  className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                  placeholder="Campaign name"
+                />
+              </div>
+
+              <div>
+                <label className="block text-sm font-medium text-text-primary mb-1">Description</label>
+                <textarea
+                  value={formData.description}
+                  onChange={e => setFormData(f => ({ ...f, description: e.target.value }))}
+                  rows={3}
+                  className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary resize-none"
+                  placeholder="Campaign description..."
+                />
+              </div>
+
+              <div className="grid grid-cols-2 gap-4">
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Brand</label>
+                  <select
+                    value={formData.brand_id}
+                    onChange={e => setFormData(f => ({ ...f, brand_id: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                  >
+                    <option value="">Select brand</option>
+                    {brands.map(b => <option key={b.id || b._id} value={b.id || b._id}>{b.icon} {b.name}</option>)}
+                  </select>
+                </div>
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Status</label>
+                  <select
+                    value={formData.status}
+                    onChange={e => setFormData(f => ({ ...f, status: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                  >
+                    <option value="planning">Planning</option>
+                    <option value="active">Active</option>
+                    <option value="paused">Paused</option>
+                    <option value="completed">Completed</option>
+                    <option value="cancelled">Cancelled</option>
+                  </select>
+                </div>
+              </div>
+
+              {/* Platforms multi-select */}
+              <div>
+                <label className="block text-sm font-medium text-text-primary mb-1">Platforms</label>
+                <div className="flex flex-wrap gap-2 p-2 border border-border rounded-lg bg-white min-h-[42px]">
+                  {Object.entries(PLATFORMS).map(([k, v]) => {
+                    const checked = (formData.platforms || []).includes(k)
+                    return (
+                      <label
+                        key={k}
+                        className={`flex items-center gap-1.5 text-xs px-2.5 py-1.5 rounded-full cursor-pointer border transition-colors ${
+                          checked
+                            ? 'bg-brand-primary/10 border-brand-primary/30 text-brand-primary font-medium'
+                            : 'bg-surface-tertiary border-transparent text-text-secondary hover:bg-surface-tertiary/80'
+                        }`}
+                      >
+                        <input
+                          type="checkbox"
+                          checked={checked}
+                          onChange={() => {
+                            setFormData(f => ({
+                              ...f,
+                              platforms: checked
+                                ? f.platforms.filter(p => p !== k)
+                                : [...(f.platforms || []), k]
+                            }))
+                          }}
+                          className="sr-only"
+                        />
+                        {v.label}
+                      </label>
+                    )
+                  })}
+                </div>
+              </div>
+
+              <div className="grid grid-cols-2 gap-4">
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Start Date *</label>
+                  <input
+                    type="date"
+                    value={formData.start_date}
+                    onChange={e => setFormData(f => ({ ...f, start_date: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                  />
+                </div>
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">End Date *</label>
+                  <input
+                    type="date"
+                    value={formData.end_date}
+                    onChange={e => setFormData(f => ({ ...f, end_date: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                  />
+                </div>
+              </div>
+
+              <div className="grid grid-cols-2 gap-4">
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Budget (SAR)</label>
+                  <input
+                    type="number"
+                    value={formData.budget}
+                    onChange={e => setFormData(f => ({ ...f, budget: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                    placeholder="e.g., 50000"
+                  />
+                </div>
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Goals</label>
+                  <input
+                    type="text"
+                    value={formData.goals}
+                    onChange={e => setFormData(f => ({ ...f, goals: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                    placeholder="Campaign goals"
+                  />
+                </div>
+              </div>
+            </>
+          ) : (
+            /* Performance & ROI Tab */
+            <>
+              {/* Live metrics summary */}
+              {(formData.budget_spent || formData.impressions || formData.clicks) && (
+                <div className="grid grid-cols-4 gap-2 mb-2">
+                  <MetricCard icon={DollarSign} label="Spent" value={formData.budget_spent ? `${Number(formData.budget_spent).toLocaleString()} SAR` : null} color="text-amber-600" />
+                  <MetricCard icon={Eye} label="Impressions" value={formData.impressions ? Number(formData.impressions).toLocaleString() : null} color="text-purple-600" />
+                  <MetricCard icon={MousePointer} label="Clicks" value={formData.clicks ? Number(formData.clicks).toLocaleString() : null} color="text-blue-600" />
+                  <MetricCard icon={Target} label="Conversions" value={formData.conversions ? Number(formData.conversions).toLocaleString() : null} color="text-emerald-600" />
+                </div>
+              )}
+
+              {formData.budget && formData.budget_spent && (
+                <div className="p-3 bg-surface-secondary rounded-lg">
+                  <BudgetBar budget={Number(formData.budget)} spent={Number(formData.budget_spent)} />
+                  <div className="flex items-center gap-2 mt-2">
+                    <ROIBadge revenue={Number(formData.revenue) || 0} spent={Number(formData.budget_spent) || 0} />
+                    {formData.clicks > 0 && formData.budget_spent > 0 && (
+                      <span className="text-[10px] text-text-tertiary">
+                        CPC: {(Number(formData.budget_spent) / Number(formData.clicks)).toFixed(2)} SAR
+                      </span>
+                    )}
+                    {formData.impressions > 0 && formData.clicks > 0 && (
+                      <span className="text-[10px] text-text-tertiary">
+                        CTR: {(Number(formData.clicks) / Number(formData.impressions) * 100).toFixed(2)}%
+                      </span>
+                    )}
+                  </div>
+                </div>
+              )}
+
+              <div className="grid grid-cols-2 gap-4">
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Budget Spent (SAR)</label>
+                  <input
+                    type="number"
+                    value={formData.budget_spent}
+                    onChange={e => setFormData(f => ({ ...f, budget_spent: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                    placeholder="Amount spent so far"
+                  />
+                </div>
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Revenue (SAR)</label>
+                  <input
+                    type="number"
+                    value={formData.revenue}
+                    onChange={e => setFormData(f => ({ ...f, revenue: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                    placeholder="Revenue generated"
+                  />
+                </div>
+              </div>
+
+              <div className="grid grid-cols-3 gap-4">
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Impressions</label>
+                  <input
+                    type="number"
+                    value={formData.impressions}
+                    onChange={e => setFormData(f => ({ ...f, impressions: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                    placeholder="Total impressions"
+                  />
+                </div>
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Clicks</label>
+                  <input
+                    type="number"
+                    value={formData.clicks}
+                    onChange={e => setFormData(f => ({ ...f, clicks: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                    placeholder="Total clicks"
+                  />
+                </div>
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">Conversions</label>
+                  <input
+                    type="number"
+                    value={formData.conversions}
+                    onChange={e => setFormData(f => ({ ...f, conversions: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                    placeholder="Conversions (visits, tickets...)"
+                  />
+                </div>
+              </div>
+
+              <div>
+                <label className="block text-sm font-medium text-text-primary mb-1">Notes</label>
+                <textarea
+                  value={formData.notes}
+                  onChange={e => setFormData(f => ({ ...f, notes: e.target.value }))}
+                  rows={3}
+                  className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary resize-none"
+                  placeholder="Performance notes, observations, what's working..."
+                />
+              </div>
+            </>
+          )}
+
+          <div className="flex items-center justify-end gap-3 pt-4 border-t border-border">
+            {editingCampaign && permissions?.canDeleteCampaigns && (
+              <button
+                onClick={() => setShowDeleteConfirm(true)}
+                className="px-4 py-2 text-sm font-medium text-red-600 hover:bg-red-50 rounded-lg mr-auto"
+              >
+                Delete
+              </button>
+            )}
+            <button
+              onClick={() => { setShowModal(false); setEditingCampaign(null) }}
+              className="px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg"
+            >
+              Cancel
+            </button>
+            <button
+              onClick={handleSave}
+              disabled={!formData.name || !formData.start_date || !formData.end_date}
+              className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm"
+            >
+              {editingCampaign ? 'Save Changes' : 'Create Campaign'}
+            </button>
+          </div>
+        </div>
+      </Modal>
+
+      {/* Delete Confirmation */}
+      <Modal
+        isOpen={showDeleteConfirm}
+        onClose={() => setShowDeleteConfirm(false)}
+        title="Delete Campaign?"
+        isConfirm
+        danger
+        confirmText="Delete Campaign"
+        onConfirm={async () => {
+          if (editingCampaign) {
+            await api.delete(`/campaigns/${editingCampaign.id || editingCampaign._id}`)
+            setShowModal(false)
+            setEditingCampaign(null)
+            loadCampaigns()
+          }
+        }}
+      >
+        Are you sure you want to delete this campaign? All associated posts and tracks will also be deleted. This action cannot be undone.
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/pages/Dashboard.jsx b/client/src/pages/Dashboard.jsx
new file mode 100644
index 0000000..4805731
--- /dev/null
+++ b/client/src/pages/Dashboard.jsx
@@ -0,0 +1,311 @@
+import { useContext, useEffect, useState } from 'react'
+import { Link } from 'react-router-dom'
+import { format, isAfter, isBefore, addDays } from 'date-fns'
+import { FileText, Megaphone, AlertTriangle, Users, ArrowRight, Clock, Wallet, TrendingUp, DollarSign, PiggyBank } from 'lucide-react'
+import { AppContext } from '../App'
+import { useLanguage } from '../i18n/LanguageContext'
+import { api } from '../utils/api'
+import StatCard from '../components/StatCard'
+import StatusBadge from '../components/StatusBadge'
+import BrandBadge from '../components/BrandBadge'
+
+function FinanceMini({ finance }) {
+  const { t } = useLanguage()
+  if (!finance) return null
+  const totalReceived = finance.totalReceived || 0
+  const spent = finance.spent || 0
+  const remaining = finance.remaining || 0
+  const roi = finance.roi || 0
+  const pct = totalReceived > 0 ? (spent / totalReceived) * 100 : 0
+  const barColor = pct > 90 ? 'bg-red-500' : pct > 70 ? 'bg-amber-500' : 'bg-emerald-500'
+
+  return (
+    <div className="bg-white rounded-xl border border-border p-5">
+      <div className="flex items-center justify-between mb-4">
+        <h3 className="font-semibold text-text-primary">{t('dashboard.budgetOverview')}</h3>
+        <Link to="/finance" className="text-sm text-brand-primary hover:text-brand-primary-light font-medium flex items-center gap-1">
+          {t('dashboard.details')} <ArrowRight className="w-3.5 h-3.5" />
+        </Link>
+      </div>
+
+      {totalReceived === 0 ? (
+        <div className="text-center py-6 text-sm text-text-tertiary">
+          {t('dashboard.noBudgetRecorded')}. <Link to="/finance" className="text-brand-primary underline">{t('dashboard.addBudget')}</Link>
+        </div>
+      ) : (
+        <>
+          {/* Budget bar */}
+          <div className="mb-4">
+            <div className="flex justify-between text-xs text-text-tertiary mb-1">
+              <span>{spent.toLocaleString()} {t('dashboard.sar')} {t('dashboard.spent')}</span>
+              <span>{totalReceived.toLocaleString()} {t('dashboard.sar')} {t('dashboard.received')}</span>
+            </div>
+            <div className="h-3 bg-surface-tertiary rounded-full overflow-hidden">
+              <div className={`h-full ${barColor} rounded-full transition-all`} style={{ width: `${Math.min(pct, 100)}%` }} />
+            </div>
+          </div>
+
+          {/* Key numbers */}
+          <div className="grid grid-cols-3 gap-3">
+            <div className="text-center p-2 bg-surface-secondary rounded-lg">
+              <PiggyBank className="w-4 h-4 mx-auto mb-1 text-emerald-500" />
+              <div className={`text-sm font-bold ${remaining >= 0 ? 'text-emerald-600' : 'text-red-600'}`}>
+                {remaining.toLocaleString()}
+              </div>
+              <div className="text-[10px] text-text-tertiary">{t('dashboard.remaining')}</div>
+            </div>
+            <div className="text-center p-2 bg-surface-secondary rounded-lg">
+              <DollarSign className="w-4 h-4 mx-auto mb-1 text-purple-500" />
+              <div className="text-sm font-bold text-purple-600">{(finance.revenue || 0).toLocaleString()}</div>
+              <div className="text-[10px] text-text-tertiary">{t('dashboard.revenue')}</div>
+            </div>
+            <div className="text-center p-2 bg-surface-secondary rounded-lg">
+              <TrendingUp className="w-4 h-4 mx-auto mb-1 text-blue-500" />
+              <div className={`text-sm font-bold ${roi >= 0 ? 'text-emerald-600' : 'text-red-600'}`}>
+                {roi.toFixed(0)}%
+              </div>
+              <div className="text-[10px] text-text-tertiary">{t('dashboard.roi')}</div>
+            </div>
+          </div>
+        </>
+      )}
+    </div>
+  )
+}
+
+function ActiveCampaignsList({ campaigns, finance }) {
+  const active = campaigns.filter(c => c.status === 'active')
+  const campaignData = (finance?.campaigns || []).filter(c => c.status === 'active')
+
+  if (active.length === 0) return null
+
+  return (
+    <div className="bg-white rounded-xl border border-border">
+      <div className="flex items-center justify-between px-5 py-4 border-b border-border">
+        <h3 className="font-semibold text-text-primary">{t('dashboard.activeCampaigns')}</h3>
+        <Link to="/campaigns" className="text-sm text-brand-primary hover:text-brand-primary-light font-medium flex items-center gap-1">
+          {t('dashboard.viewAll')} <ArrowRight className="w-3.5 h-3.5" />
+        </Link>
+      </div>
+      <div className="divide-y divide-border-light">
+        {active.map(c => {
+          const cd = campaignData.find(d => d.id === (c._id || c.id)) || {}
+          const spent = cd.tracks_spent || 0
+          const allocated = cd.tracks_allocated || 0
+          const pct = allocated > 0 ? (spent / allocated) * 100 : 0
+          const barColor = pct > 90 ? 'bg-red-500' : pct > 70 ? 'bg-amber-500' : 'bg-emerald-500'
+          return (
+            <Link key={c._id || c.id} to={`/campaigns/${c._id || c.id}`} className="flex items-center gap-4 px-5 py-3 hover:bg-surface-secondary transition-colors">
+              <div className="flex-1 min-w-0">
+                <p className="text-sm font-medium text-text-primary truncate">{c.name}</p>
+                {allocated > 0 && (
+                  <div className="mt-1.5 w-32">
+                    <div className="flex justify-between text-[9px] text-text-tertiary mb-0.5">
+                      <span>{spent.toLocaleString()}</span>
+                      <span>{allocated.toLocaleString()} SAR</span>
+                    </div>
+                    <div className="h-1.5 bg-surface-tertiary rounded-full overflow-hidden">
+                      <div className={`h-full ${barColor} rounded-full`} style={{ width: `${Math.min(pct, 100)}%` }} />
+                    </div>
+                  </div>
+                )}
+              </div>
+              <div className="text-right shrink-0">
+                {cd.tracks_impressions > 0 && (
+                  <div className="text-[10px] text-text-tertiary">
+                    👁 {cd.tracks_impressions.toLocaleString()} · 🖱 {cd.tracks_clicks.toLocaleString()}
+                  </div>
+                )}
+              </div>
+            </Link>
+          )
+        })}
+      </div>
+    </div>
+  )
+}
+
+export default function Dashboard() {
+  const { t } = useLanguage()
+  const { currentUser, teamMembers } = useContext(AppContext)
+  const [posts, setPosts] = useState([])
+  const [campaigns, setCampaigns] = useState([])
+  const [tasks, setTasks] = useState([])
+  const [finance, setFinance] = useState(null)
+  const [loading, setLoading] = useState(true)
+
+  useEffect(() => {
+    loadData()
+  }, [])
+
+  const loadData = async () => {
+    try {
+      const [postsRes, campaignsRes, tasksRes, financeRes] = await Promise.allSettled([
+        api.get('/posts?limit=10&sort=-createdAt'),
+        api.get('/campaigns'),
+        api.get('/tasks'),
+        api.get('/finance/summary'),
+      ])
+      setPosts(postsRes.status === 'fulfilled' ? (postsRes.value.data || postsRes.value || []) : [])
+      setCampaigns(campaignsRes.status === 'fulfilled' ? (campaignsRes.value.data || campaignsRes.value || []) : [])
+      setTasks(tasksRes.status === 'fulfilled' ? (tasksRes.value.data || tasksRes.value || []) : [])
+      setFinance(financeRes.status === 'fulfilled' ? (financeRes.value.data || financeRes.value || null) : null)
+    } catch (err) {
+      console.error('Dashboard load error:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const activeCampaigns = campaigns.filter(c => c.status === 'active').length
+  const overdueTasks = tasks.filter(t =>
+    t.dueDate && new Date(t.dueDate) < new Date() && t.status !== 'done'
+  ).length
+
+  const upcomingDeadlines = tasks
+    .filter(t => {
+      if (!t.dueDate || t.status === 'done') return false
+      const due = new Date(t.dueDate)
+      const now = new Date()
+      return isAfter(due, now) && isBefore(due, addDays(now, 7))
+    })
+    .sort((a, b) => new Date(a.dueDate) - new Date(b.dueDate))
+    .slice(0, 8)
+
+  if (loading) {
+    return (
+      <div className="space-y-6 animate-pulse">
+        <div className="h-8 w-64 bg-surface-tertiary rounded-lg"></div>
+        <div className="grid grid-cols-4 gap-4">
+          {[...Array(4)].map((_, i) => (
+            <div key={i} className="h-28 bg-surface-tertiary rounded-xl"></div>
+          ))}
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-6 animate-fade-in">
+      {/* Welcome */}
+      <div>
+        <h1 className="text-2xl font-bold text-text-primary">
+          Welcome back, {currentUser?.name || 'there'} 👋
+        </h1>
+        <p className="text-text-secondary mt-1">
+          Here's what's happening with your marketing today.
+        </p>
+      </div>
+
+      {/* Stats */}
+      <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-4 stagger-children">
+        <StatCard
+          icon={FileText}
+          label="Total Posts"
+          value={posts.length || 0}
+          subtitle={`${posts.filter(p => p.status === 'published').length} published`}
+          color="brand-primary"
+        />
+        <StatCard
+          icon={Megaphone}
+          label="Active Campaigns"
+          value={activeCampaigns}
+          subtitle={`${campaigns.length} total`}
+          color="brand-secondary"
+        />
+        <StatCard
+          icon={Wallet}
+          label="Budget Spent"
+          value={`${((finance?.spent || 0)).toLocaleString()}`}
+          subtitle={finance?.totalReceived ? `of ${finance.totalReceived.toLocaleString()} SAR` : 'No budget yet'}
+          color="brand-tertiary"
+        />
+        <StatCard
+          icon={AlertTriangle}
+          label="Overdue Tasks"
+          value={overdueTasks}
+          subtitle={overdueTasks > 0 ? 'Needs attention' : 'All on track'}
+          color="brand-quaternary"
+        />
+      </div>
+
+      {/* Three columns on large, stack on small */}
+      <div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
+        {/* Budget Overview */}
+        <FinanceMini finance={finance} />
+
+        {/* Active Campaigns with budget bars */}
+        <div className="lg:col-span-2">
+          <ActiveCampaignsList campaigns={campaigns} finance={finance} />
+        </div>
+      </div>
+
+      {/* Two columns */}
+      <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
+        {/* Recent Posts */}
+        <div className="bg-white rounded-xl border border-border">
+          <div className="flex items-center justify-between px-5 py-4 border-b border-border">
+            <h3 className="font-semibold text-text-primary">Recent Posts</h3>
+            <Link to="/posts" className="text-sm text-brand-primary hover:text-brand-primary-light font-medium flex items-center gap-1">
+              View all <ArrowRight className="w-3.5 h-3.5" />
+            </Link>
+          </div>
+          <div className="divide-y divide-border-light">
+            {posts.length === 0 ? (
+              <div className="py-12 text-center text-sm text-text-tertiary">
+                No posts yet. Create your first post!
+              </div>
+            ) : (
+              posts.slice(0, 8).map((post) => (
+                <div key={post._id} className="flex items-center gap-3 px-5 py-3 hover:bg-surface-secondary transition-colors">
+                  <div className="flex-1 min-w-0">
+                    <p className="text-sm font-medium text-text-primary truncate">{post.title}</p>
+                    <div className="flex items-center gap-2 mt-1">
+                      {post.brand && <BrandBadge brand={post.brand} />}
+                    </div>
+                  </div>
+                  <StatusBadge status={post.status} size="xs" />
+                </div>
+              ))
+            )}
+          </div>
+        </div>
+
+        {/* Upcoming Deadlines */}
+        <div className="bg-white rounded-xl border border-border">
+          <div className="flex items-center justify-between px-5 py-4 border-b border-border">
+            <h3 className="font-semibold text-text-primary">Upcoming Deadlines</h3>
+            <Link to="/tasks" className="text-sm text-brand-primary hover:text-brand-primary-light font-medium flex items-center gap-1">
+              View all <ArrowRight className="w-3.5 h-3.5" />
+            </Link>
+          </div>
+          <div className="divide-y divide-border-light">
+            {upcomingDeadlines.length === 0 ? (
+              <div className="py-12 text-center text-sm text-text-tertiary">
+                No upcoming deadlines this week. 🎉
+              </div>
+            ) : (
+              upcomingDeadlines.map((task) => (
+                <div key={task._id} className="flex items-center gap-3 px-5 py-3 hover:bg-surface-secondary transition-colors">
+                  <div className={`w-2 h-2 rounded-full ${
+                    task.priority === 'urgent' ? 'bg-red-500' :
+                    task.priority === 'high' ? 'bg-orange-500' :
+                    task.priority === 'medium' ? 'bg-amber-400' : 'bg-gray-400'
+                  }`} />
+                  <div className="flex-1 min-w-0">
+                    <p className="text-sm font-medium text-text-primary truncate">{task.title}</p>
+                    <StatusBadge status={task.status} size="xs" />
+                  </div>
+                  <div className="flex items-center gap-1 text-xs text-text-tertiary shrink-0">
+                    <Clock className="w-3.5 h-3.5" />
+                    {format(new Date(task.dueDate), 'MMM d')}
+                  </div>
+                </div>
+              ))
+            )}
+          </div>
+        </div>
+      </div>
+    </div>
+  )
+}
diff --git a/client/src/pages/Finance.jsx b/client/src/pages/Finance.jsx
new file mode 100644
index 0000000..818191e
--- /dev/null
+++ b/client/src/pages/Finance.jsx
@@ -0,0 +1,434 @@
+import { useState, useEffect, useContext } from 'react'
+import { Plus, DollarSign, TrendingUp, TrendingDown, Wallet, PiggyBank, Eye, MousePointer, Target, Edit2, Trash2 } from 'lucide-react'
+import { format } from 'date-fns'
+import { AppContext } from '../App'
+import { api } from '../utils/api'
+import Modal from '../components/Modal'
+import StatusBadge from '../components/StatusBadge'
+
+const CATEGORIES = [
+  { value: 'marketing', label: 'Marketing' },
+  { value: 'production', label: 'Production' },
+  { value: 'equipment', label: 'Equipment' },
+  { value: 'travel', label: 'Travel' },
+  { value: 'other', label: 'Other' },
+]
+
+const EMPTY_ENTRY = {
+  label: '', amount: '', source: '', campaign_id: '', category: 'marketing', date_received: new Date().toISOString().slice(0, 10), notes: '',
+}
+
+function StatCard({ icon: Icon, label, value, sub, color = 'text-text-primary', bgColor = 'bg-white' }) {
+  return (
+    <div className={`${bgColor} rounded-xl border border-border p-5`}>
+      <div className="flex items-center gap-2 mb-2">
+        <div className={`p-2 rounded-lg ${color.replace('text-', 'bg-')}/10`}>
+          <Icon className={`w-5 h-5 ${color}`} />
+        </div>
+        <span className="text-xs uppercase tracking-wider text-text-tertiary font-medium">{label}</span>
+      </div>
+      <div className={`text-2xl font-bold ${color}`}>{value}</div>
+      {sub && <div className="text-xs text-text-tertiary mt-1">{sub}</div>}
+    </div>
+  )
+}
+
+function ProgressRing({ pct, size = 80, stroke = 8, color = '#10b981' }) {
+  const r = (size - stroke) / 2
+  const circ = 2 * Math.PI * r
+  const offset = circ - (Math.min(pct, 100) / 100) * circ
+  return (
+    <svg width={size} height={size} className="transform -rotate-90">
+      <circle cx={size / 2} cy={size / 2} r={r} fill="none" stroke="#f3f4f6" strokeWidth={stroke} />
+      <circle cx={size / 2} cy={size / 2} r={r} fill="none" stroke={color} strokeWidth={stroke}
+        strokeDasharray={circ} strokeDashoffset={offset} strokeLinecap="round" className="transition-all duration-500" />
+      <text x={size / 2} y={size / 2} textAnchor="middle" dominantBaseline="central"
+        className="fill-text-primary text-sm font-bold" transform={`rotate(90 ${size / 2} ${size / 2})`}>
+        {Math.round(pct)}%
+      </text>
+    </svg>
+  )
+}
+
+export default function Finance() {
+  const { brands } = useContext(AppContext)
+  const [entries, setEntries] = useState([])
+  const [summary, setSummary] = useState(null)
+  const [campaigns, setCampaigns] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [showModal, setShowModal] = useState(false)
+  const [editing, setEditing] = useState(null)
+  const [form, setForm] = useState(EMPTY_ENTRY)
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+  const [entryToDelete, setEntryToDelete] = useState(null)
+
+  useEffect(() => { loadAll() }, [])
+
+  const loadAll = async () => {
+    try {
+      const [ent, sum, camp] = await Promise.all([
+        api.get('/budget'),
+        api.get('/finance/summary'),
+        api.get('/campaigns'),
+      ])
+      setEntries(ent.data || ent || [])
+      setSummary(sum.data || sum || {})
+      setCampaigns(camp.data || camp || [])
+    } catch (err) {
+      console.error('Failed to load finance:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleSave = async () => {
+    try {
+      const data = {
+        label: form.label,
+        amount: Number(form.amount),
+        source: form.source || null,
+        campaign_id: form.campaign_id ? Number(form.campaign_id) : null,
+        category: form.category,
+        date_received: form.date_received,
+        notes: form.notes,
+      }
+      if (editing) {
+        await api.patch(`/budget/${editing._id || editing.id}`, data)
+      } else {
+        await api.post('/budget', data)
+      }
+      setShowModal(false)
+      setEditing(null)
+      setForm(EMPTY_ENTRY)
+      loadAll()
+    } catch (err) {
+      console.error('Save failed:', err)
+    }
+  }
+
+  const openEdit = (entry) => {
+    setEditing(entry)
+    setForm({
+      label: entry.label || '',
+      amount: entry.amount || '',
+      source: entry.source || '',
+      campaign_id: entry.campaignId || entry.campaign_id || '',
+      category: entry.category || 'marketing',
+      date_received: entry.dateReceived || entry.date_received || '',
+      notes: entry.notes || '',
+    })
+    setShowModal(true)
+  }
+
+  const handleDelete = async (id) => {
+    setEntryToDelete(id)
+    setShowDeleteConfirm(true)
+  }
+
+  const confirmDelete = async () => {
+    if (!entryToDelete) return
+    await api.delete(`/budget/${entryToDelete}`)
+    setEntryToDelete(null)
+    loadAll()
+  }
+
+  if (loading) {
+    return (
+      <div className="space-y-4 animate-pulse">
+        <div className="grid grid-cols-4 gap-4">
+          {[1, 2, 3, 4].map(i => <div key={i} className="h-28 bg-surface-tertiary rounded-xl" />)}
+        </div>
+      </div>
+    )
+  }
+
+  const s = summary || {}
+  const totalReceived = s.totalReceived || 0
+  const totalSpent = s.spent || 0
+  const remaining = s.remaining || 0
+  const totalRevenue = s.revenue || 0
+  const roi = s.roi || 0
+  const spendPct = totalReceived > 0 ? (totalSpent / totalReceived) * 100 : 0
+
+  return (
+    <div className="space-y-6 animate-fade-in">
+      {/* Top metrics */}
+      <div className="grid grid-cols-2 lg:grid-cols-5 gap-4">
+        <StatCard icon={Wallet} label="Total Received" value={`${totalReceived.toLocaleString()} SAR`} color="text-blue-600" />
+        <StatCard icon={TrendingUp} label="Total Spent" value={`${totalSpent.toLocaleString()} SAR`} sub={`${spendPct.toFixed(1)}% of budget`} color="text-amber-600" />
+        <StatCard icon={PiggyBank} label="Remaining" value={`${remaining.toLocaleString()} SAR`} color={remaining >= 0 ? 'text-emerald-600' : 'text-red-600'} />
+        <StatCard icon={DollarSign} label="Revenue" value={`${totalRevenue.toLocaleString()} SAR`} color="text-purple-600" />
+        <StatCard icon={roi >= 0 ? TrendingUp : TrendingDown} label="Global ROI"
+          value={`${roi.toFixed(1)}%`}
+          color={roi >= 0 ? 'text-emerald-600' : 'text-red-600'} />
+      </div>
+
+      {/* Budget utilization + Global metrics */}
+      <div className="grid grid-cols-1 lg:grid-cols-3 gap-4">
+        {/* Utilization ring */}
+        <div className="bg-white rounded-xl border border-border p-5 flex flex-col items-center justify-center">
+          <h3 className="text-xs uppercase tracking-wider text-text-tertiary font-medium mb-4">Budget Utilization</h3>
+          <ProgressRing
+            pct={spendPct}
+            size={120}
+            stroke={10}
+            color={spendPct > 90 ? '#ef4444' : spendPct > 70 ? '#f59e0b' : '#10b981'}
+          />
+          <div className="text-xs text-text-tertiary mt-3">
+            {totalSpent.toLocaleString()} of {totalReceived.toLocaleString()} SAR
+          </div>
+        </div>
+
+        {/* Global performance */}
+        <div className="bg-white rounded-xl border border-border p-5 lg:col-span-2">
+          <h3 className="text-xs uppercase tracking-wider text-text-tertiary font-medium mb-4">Global Performance</h3>
+          <div className="grid grid-cols-3 gap-6">
+            <div className="text-center">
+              <Eye className="w-5 h-5 mx-auto mb-1 text-purple-500" />
+              <div className="text-xl font-bold text-text-primary">{(s.impressions || 0).toLocaleString()}</div>
+              <div className="text-xs text-text-tertiary">Impressions</div>
+            </div>
+            <div className="text-center">
+              <MousePointer className="w-5 h-5 mx-auto mb-1 text-blue-500" />
+              <div className="text-xl font-bold text-text-primary">{(s.clicks || 0).toLocaleString()}</div>
+              <div className="text-xs text-text-tertiary">Clicks</div>
+              {s.clicks > 0 && s.spent > 0 && (
+                <div className="text-[10px] text-text-tertiary mt-0.5">CPC: {(s.spent / s.clicks).toFixed(2)} SAR</div>
+              )}
+            </div>
+            <div className="text-center">
+              <Target className="w-5 h-5 mx-auto mb-1 text-emerald-500" />
+              <div className="text-xl font-bold text-text-primary">{(s.conversions || 0).toLocaleString()}</div>
+              <div className="text-xs text-text-tertiary">Conversions</div>
+              {s.conversions > 0 && s.spent > 0 && (
+                <div className="text-[10px] text-text-tertiary mt-0.5">CPA: {(s.spent / s.conversions).toFixed(2)} SAR</div>
+              )}
+            </div>
+          </div>
+          {s.impressions > 0 && s.clicks > 0 && (
+            <div className="mt-4 pt-3 border-t border-border text-center">
+              <span className="text-xs text-text-tertiary">
+                CTR: {(s.clicks / s.impressions * 100).toFixed(2)}%
+                {s.conversions > 0 && s.clicks > 0 && ` · Conv. Rate: ${(s.conversions / s.clicks * 100).toFixed(2)}%`}
+              </span>
+            </div>
+          )}
+        </div>
+      </div>
+
+      {/* Per-campaign breakdown */}
+      {s.campaigns && s.campaigns.length > 0 && (
+        <div className="bg-white rounded-xl border border-border overflow-hidden">
+          <div className="px-5 py-4 border-b border-border">
+            <h3 className="font-semibold text-text-primary">Campaign Breakdown</h3>
+          </div>
+          <div className="overflow-x-auto">
+            <table className="w-full text-sm">
+              <thead>
+                <tr className="border-b border-border bg-surface-secondary">
+                  <th className="px-4 py-3 text-left text-xs font-medium text-text-tertiary">Campaign</th>
+                  <th className="px-4 py-3 text-right text-xs font-medium text-text-tertiary">Allocated</th>
+                  <th className="px-4 py-3 text-right text-xs font-medium text-text-tertiary">Spent</th>
+                  <th className="px-4 py-3 text-right text-xs font-medium text-text-tertiary">Revenue</th>
+                  <th className="px-4 py-3 text-right text-xs font-medium text-text-tertiary">ROI</th>
+                  <th className="px-4 py-3 text-right text-xs font-medium text-text-tertiary">Impressions</th>
+                  <th className="px-4 py-3 text-right text-xs font-medium text-text-tertiary">Clicks</th>
+                  <th className="px-4 py-3 text-center text-xs font-medium text-text-tertiary">Status</th>
+                </tr>
+              </thead>
+              <tbody className="divide-y divide-border-light">
+                {s.campaigns.map(c => {
+                  const cRoi = c.tracks_spent > 0 ? ((c.tracks_revenue - c.tracks_spent) / c.tracks_spent * 100) : 0
+                  return (
+                    <tr key={c.id} className="hover:bg-surface-secondary">
+                      <td className="px-4 py-3 font-medium text-text-primary">{c.name}</td>
+                      <td className="px-4 py-3 text-right text-text-secondary">{c.tracks_allocated.toLocaleString()}</td>
+                      <td className="px-4 py-3 text-right text-text-secondary">{c.tracks_spent.toLocaleString()}</td>
+                      <td className="px-4 py-3 text-right text-text-secondary">{c.tracks_revenue.toLocaleString()}</td>
+                      <td className="px-4 py-3 text-right">
+                        {c.tracks_spent > 0 ? (
+                          <span className={`text-xs font-semibold px-1.5 py-0.5 rounded ${cRoi >= 0 ? 'text-emerald-600 bg-emerald-50' : 'text-red-600 bg-red-50'}`}>
+                            {cRoi.toFixed(0)}%
+                          </span>
+                        ) : '—'}
+                      </td>
+                      <td className="px-4 py-3 text-right text-text-secondary">{c.tracks_impressions.toLocaleString()}</td>
+                      <td className="px-4 py-3 text-right text-text-secondary">{c.tracks_clicks.toLocaleString()}</td>
+                      <td className="px-4 py-3 text-center"><StatusBadge status={c.status} size="xs" /></td>
+                    </tr>
+                  )
+                })}
+              </tbody>
+            </table>
+          </div>
+        </div>
+      )}
+
+      {/* Budget entries */}
+      <div className="bg-white rounded-xl border border-border overflow-hidden">
+        <div className="flex items-center justify-between px-5 py-4 border-b border-border">
+          <h3 className="font-semibold text-text-primary">Budget Received</h3>
+          <button
+            onClick={() => { setEditing(null); setForm(EMPTY_ENTRY); setShowModal(true) }}
+            className="flex items-center gap-1.5 px-3 py-1.5 bg-brand-primary text-white rounded-lg text-xs font-medium hover:bg-brand-primary-light"
+          >
+            <Plus className="w-3.5 h-3.5" /> Add Entry
+          </button>
+        </div>
+
+        {entries.length === 0 ? (
+          <div className="py-12 text-center text-sm text-text-tertiary">
+            No budget entries yet. Add your first received budget.
+          </div>
+        ) : (
+          <div className="divide-y divide-border-light">
+            {entries.map(entry => (
+              <div key={entry.id || entry._id} className="flex items-center gap-4 px-5 py-4 hover:bg-surface-secondary">
+                <div className="p-2 rounded-lg bg-emerald-50">
+                  <DollarSign className="w-4 h-4 text-emerald-600" />
+                </div>
+                <div className="flex-1 min-w-0">
+                  <div className="flex items-center gap-2 mb-0.5">
+                    <h4 className="text-sm font-semibold text-text-primary">{entry.label}</h4>
+                    <span className="text-[10px] px-1.5 py-0.5 rounded bg-surface-tertiary text-text-tertiary capitalize">
+                      {entry.category}
+                    </span>
+                  </div>
+                  <div className="text-xs text-text-tertiary">
+                    {entry.source && <span>{entry.source} · </span>}
+                    {entry.campaign_name && <span>{entry.campaign_name} · </span>}
+                    {entry.date_received && format(new Date(entry.date_received), 'MMM d, yyyy')}
+                  </div>
+                  {entry.notes && <p className="text-xs text-text-secondary mt-0.5">{entry.notes}</p>}
+                </div>
+                <div className="text-right shrink-0">
+                  <div className="text-base font-bold text-emerald-600">{Number(entry.amount).toLocaleString()} SAR</div>
+                </div>
+                <div className="flex items-center gap-1 shrink-0">
+                  <button onClick={() => openEdit(entry)} className="p-1.5 hover:bg-surface-tertiary rounded-lg text-text-tertiary hover:text-text-primary">
+                    <Edit2 className="w-4 h-4" />
+                  </button>
+                  <button onClick={() => handleDelete(entry.id || entry._id)} className="p-1.5 hover:bg-red-50 rounded-lg text-text-tertiary hover:text-red-500">
+                    <Trash2 className="w-4 h-4" />
+                  </button>
+                </div>
+              </div>
+            ))}
+          </div>
+        )}
+      </div>
+
+      {/* Add/Edit Modal */}
+      <Modal
+        isOpen={showModal}
+        onClose={() => { setShowModal(false); setEditing(null) }}
+        title={editing ? 'Edit Budget Entry' : 'Add Budget Entry'}
+      >
+        <div className="space-y-4">
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Label *</label>
+            <input
+              type="text"
+              value={form.label}
+              onChange={e => setForm(f => ({ ...f, label: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder="e.g., Seerah Campaign Budget, Additional Q1 Funds..."
+            />
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Amount (SAR) *</label>
+              <input
+                type="number"
+                value={form.amount}
+                onChange={e => setForm(f => ({ ...f, amount: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                placeholder="50000"
+              />
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Date Received *</label>
+              <input
+                type="date"
+                value={form.date_received}
+                onChange={e => setForm(f => ({ ...f, date_received: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              />
+            </div>
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Source</label>
+              <input
+                type="text"
+                value={form.source}
+                onChange={e => setForm(f => ({ ...f, source: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+                placeholder="e.g., CEO Approval, Annual Budget..."
+              />
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Category</label>
+              <select
+                value={form.category}
+                onChange={e => setForm(f => ({ ...f, category: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+              >
+                {CATEGORIES.map(c => <option key={c.value} value={c.value}>{c.label}</option>)}
+              </select>
+            </div>
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Campaign (optional)</label>
+            <select
+              value={form.campaign_id}
+              onChange={e => setForm(f => ({ ...f, campaign_id: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none"
+            >
+              <option value="">General / Not linked</option>
+              {campaigns.map(c => <option key={c._id || c.id} value={c._id || c.id}>{c.name}</option>)}
+            </select>
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Notes</label>
+            <textarea
+              value={form.notes}
+              onChange={e => setForm(f => ({ ...f, notes: e.target.value }))}
+              rows={2}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none resize-none"
+              placeholder="Any details about this budget entry..."
+            />
+          </div>
+
+          <div className="flex justify-end gap-3 pt-4 border-t border-border">
+            <button onClick={() => setShowModal(false)} className="px-4 py-2 text-sm text-text-secondary hover:bg-surface-tertiary rounded-lg">Cancel</button>
+            <button
+              onClick={handleSave}
+              disabled={!form.label || !form.amount || !form.date_received}
+              className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm"
+            >
+              {editing ? 'Save Changes' : 'Add Entry'}
+            </button>
+          </div>
+        </div>
+      </Modal>
+
+      {/* Delete Budget Entry Confirmation */}
+      <Modal
+        isOpen={showDeleteConfirm}
+        onClose={() => { setShowDeleteConfirm(false); setEntryToDelete(null) }}
+        title="Delete Budget Entry?"
+        isConfirm
+        danger
+        confirmText="Delete Entry"
+        onConfirm={confirmDelete}
+      >
+        Are you sure you want to delete this budget entry? This action cannot be undone.
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/pages/Login.jsx b/client/src/pages/Login.jsx
new file mode 100644
index 0000000..788d60e
--- /dev/null
+++ b/client/src/pages/Login.jsx
@@ -0,0 +1,119 @@
+import { useState } from 'react'
+import { useNavigate } from 'react-router-dom'
+import { useAuth } from '../contexts/AuthContext'
+import { useLanguage } from '../i18n/LanguageContext'
+import { Megaphone, Lock, Mail, AlertCircle } from 'lucide-react'
+
+export default function Login() {
+  const navigate = useNavigate()
+  const { login } = useAuth()
+  const { t } = useLanguage()
+  const [email, setEmail] = useState('')
+  const [password, setPassword] = useState('')
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState('')
+
+  const handleSubmit = async (e) => {
+    e.preventDefault()
+    setError('')
+    setLoading(true)
+
+    try {
+      await login(email, password)
+      navigate('/')
+    } catch (err) {
+      setError(err.message || 'Invalid email or password')
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  return (
+    <div className="min-h-screen bg-gradient-to-br from-slate-900 via-blue-900 to-slate-900 flex items-center justify-center px-4">
+      <div className="w-full max-w-md">
+        {/* Logo & Title */}
+        <div className="text-center mb-8">
+          <div className="w-16 h-16 bg-gradient-to-br from-blue-500 to-purple-600 rounded-2xl flex items-center justify-center mx-auto mb-4 shadow-lg">
+            <Megaphone className="w-8 h-8 text-white" />
+          </div>
+          <h1 className="text-3xl font-bold text-white mb-2">{t('login.title')}</h1>
+          <p className="text-slate-400">{t('login.subtitle')}</p>
+        </div>
+
+        {/* Login Card */}
+        <div className="bg-slate-800/50 backdrop-blur-sm rounded-2xl border border-slate-700/50 p-8 shadow-2xl">
+          <form onSubmit={handleSubmit} className="space-y-5">
+            {/* Email */}
+            <div>
+              <label className="block text-sm font-medium text-slate-300 mb-2">
+                {t('auth.email')}
+              </label>
+              <div className="relative">
+                <Mail className="absolute left-3 top-1/2 -translate-y-1/2 w-5 h-5 text-slate-500" />
+                <input
+                  type="email"
+                  value={email}
+                  onChange={(e) => setEmail(e.target.value)}
+                  dir="auto"
+                  className="w-full pl-11 pr-4 py-3 bg-slate-900/50 border border-slate-700 rounded-lg text-white placeholder-slate-500 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
+                  placeholder="f.mahidi@samayainvest.com"
+                  required
+                  autoFocus
+                />
+              </div>
+            </div>
+
+            {/* Password */}
+            <div>
+              <label className="block text-sm font-medium text-slate-300 mb-2">
+                {t('auth.password')}
+              </label>
+              <div className="relative">
+                <Lock className="absolute left-3 top-1/2 -translate-y-1/2 w-5 h-5 text-slate-500" />
+                <input
+                  type="password"
+                  value={password}
+                  onChange={(e) => setPassword(e.target.value)}
+                  className="w-full pl-11 pr-4 py-3 bg-slate-900/50 border border-slate-700 rounded-lg text-white placeholder-slate-500 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent transition-all"
+                  placeholder="••••••••"
+                  required
+                />
+              </div>
+            </div>
+
+            {/* Error Message */}
+            {error && (
+              <div className="flex items-center gap-2 p-3 bg-red-500/10 border border-red-500/30 rounded-lg">
+                <AlertCircle className="w-5 h-5 text-red-400 shrink-0" />
+                <p className="text-sm text-red-400">{error}</p>
+              </div>
+            )}
+
+            {/* Submit Button */}
+            <button
+              type="submit"
+              disabled={loading}
+              className="w-full py-3 bg-gradient-to-r from-blue-600 to-purple-600 hover:from-blue-700 hover:to-purple-700 text-white font-semibold rounded-lg shadow-lg hover:shadow-xl transition-all disabled:opacity-50 disabled:cursor-not-allowed"
+            >
+              {loading ? (
+                <span className="flex items-center justify-center gap-2">
+                  <div className="w-5 h-5 border-2 border-white/30 border-t-white rounded-full animate-spin" />
+                  {t('auth.signingIn')}
+                </span>
+              ) : (
+                t('auth.loginBtn')
+              )}
+            </button>
+          </form>
+
+          {/* Default Credentials */}
+          <div className="mt-6 pt-6 border-t border-slate-700/50">
+            <p className="text-xs text-slate-500 text-center">
+              {t('login.defaultCreds')} <span className="text-slate-400 font-medium">f.mahidi@samayainvest.com</span> / <span className="text-slate-400 font-medium">admin123</span>
+            </p>
+          </div>
+        </div>
+      </div>
+    </div>
+  )
+}
diff --git a/client/src/pages/PostProduction.jsx b/client/src/pages/PostProduction.jsx
new file mode 100644
index 0000000..768c99a
--- /dev/null
+++ b/client/src/pages/PostProduction.jsx
@@ -0,0 +1,669 @@
+import { useState, useEffect, useContext, useRef } from 'react'
+import { Plus, LayoutGrid, List, Search, Filter, Upload, X, Paperclip, Link2, FileText, Image as ImageIcon, Trash2, ExternalLink } from 'lucide-react'
+import { AppContext } from '../App'
+import { useAuth } from '../contexts/AuthContext'
+import { useLanguage } from '../i18n/LanguageContext'
+import { api, PLATFORMS } from '../utils/api'
+import KanbanBoard from '../components/KanbanBoard'
+import PostCard from '../components/PostCard'
+import StatusBadge from '../components/StatusBadge'
+import Modal from '../components/Modal'
+
+const EMPTY_POST = {
+  title: '', description: '', brand_id: '', platforms: [],
+  status: 'draft', assigned_to: '', scheduled_date: '', notes: '', campaign_id: '',
+  publication_links: [],
+}
+
+export default function PostProduction() {
+  const { t } = useLanguage()
+  const { teamMembers, brands } = useContext(AppContext)
+  const { canEditResource, canDeleteResource } = useAuth()
+  const [posts, setPosts] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [view, setView] = useState('kanban')
+  const [showModal, setShowModal] = useState(false)
+  const [editingPost, setEditingPost] = useState(null)
+  const [formData, setFormData] = useState(EMPTY_POST)
+  const [campaigns, setCampaigns] = useState([])
+  const [filters, setFilters] = useState({ brand: '', platform: '', assignedTo: '', campaign: '' })
+  const [searchTerm, setSearchTerm] = useState('')
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+  const [attachments, setAttachments] = useState([])
+  const [uploading, setUploading] = useState(false)
+  const [uploadProgress, setUploadProgress] = useState(0)
+  const [publishError, setPublishError] = useState('')
+  const [dragActive, setDragActive] = useState(false)
+  const fileInputRef = useRef(null)
+
+  useEffect(() => {
+    loadPosts()
+    api.get('/campaigns').then(r => setCampaigns(Array.isArray(r) ? r : (r.data || []))).catch(() => {})
+  }, [])
+
+  const loadPosts = async () => {
+    try {
+      const res = await api.get('/posts')
+      setPosts(res.data || res || [])
+    } catch (err) {
+      console.error('Failed to load posts:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleSave = async () => {
+    setPublishError('')
+    try {
+      const data = {
+        title: formData.title,
+        description: formData.description,
+        brand_id: formData.brand_id ? Number(formData.brand_id) : null,
+        assigned_to: formData.assigned_to ? Number(formData.assigned_to) : null,
+        status: formData.status,
+        platforms: formData.platforms || [],
+        scheduled_date: formData.scheduled_date || null,
+        notes: formData.notes,
+        campaign_id: formData.campaign_id ? Number(formData.campaign_id) : null,
+        publication_links: formData.publication_links || [],
+      }
+
+      // Client-side validation: check publication links before publishing
+      if (data.status === 'published' && data.platforms.length > 0) {
+        const missingPlatforms = data.platforms.filter(platform => {
+          const link = (data.publication_links || []).find(l => l.platform === platform)
+          return !link || !link.url || !link.url.trim()
+        })
+        if (missingPlatforms.length > 0) {
+          const names = missingPlatforms.map(p => PLATFORMS[p]?.label || p).join(', ')
+          setPublishError(`${t('posts.publishMissing')} ${names}`)
+          return
+        }
+      }
+
+      if (editingPost) {
+        await api.patch(`/posts/${editingPost._id}`, data)
+      } else {
+        await api.post('/posts', data)
+      }
+      setShowModal(false)
+      setEditingPost(null)
+      setFormData(EMPTY_POST)
+      setAttachments([])
+      loadPosts()
+    } catch (err) {
+      console.error('Save failed:', err)
+      if (err.message?.includes('Cannot publish')) {
+        setPublishError(err.message.replace(/.*: /, ''))
+      }
+    }
+  }
+
+  const handleMovePost = async (postId, newStatus) => {
+    try {
+      await api.patch(`/posts/${postId}`, { status: newStatus })
+      loadPosts()
+    } catch (err) {
+      console.error('Move failed:', err)
+      if (err.message?.includes('Cannot publish')) {
+        alert('Cannot publish: all platform publication links must be filled first.')
+      }
+    }
+  }
+
+  const loadAttachments = async (postId) => {
+    try {
+      const data = await api.get(`/posts/${postId}/attachments`)
+      setAttachments(Array.isArray(data) ? data : (data.data || []))
+    } catch (err) {
+      console.error('Failed to load attachments:', err)
+      setAttachments([])
+    }
+  }
+
+  const handleFileUpload = async (files) => {
+    if (!editingPost || !files?.length) return
+    setUploading(true)
+    setUploadProgress(0)
+    const postId = editingPost._id || editingPost.id
+
+    for (let i = 0; i < files.length; i++) {
+      const fd = new FormData()
+      fd.append('file', files[i])
+      try {
+        await api.upload(`/posts/${postId}/attachments`, fd)
+        setUploadProgress(Math.round(((i + 1) / files.length) * 100))
+      } catch (err) {
+        console.error('Upload failed:', err)
+      }
+    }
+
+    setUploading(false)
+    setUploadProgress(0)
+    loadAttachments(postId)
+  }
+
+  const handleDeleteAttachment = async (attachmentId) => {
+    try {
+      await api.delete(`/attachments/${attachmentId}`)
+      if (editingPost) loadAttachments(editingPost._id || editingPost.id)
+    } catch (err) {
+      console.error('Delete attachment failed:', err)
+    }
+  }
+
+  const handleDragEnter = (e) => { e.preventDefault(); e.stopPropagation(); setDragActive(true) }
+  const handleDragLeaveZone = (e) => { e.preventDefault(); e.stopPropagation(); setDragActive(false) }
+  const handleDragOverZone = (e) => { e.preventDefault(); e.stopPropagation() }
+  const handleDropFiles = (e) => {
+    e.preventDefault(); e.stopPropagation(); setDragActive(false)
+    if (e.dataTransfer.files?.length) handleFileUpload(e.dataTransfer.files)
+  }
+
+  const updatePublicationLink = (platform, url) => {
+    setFormData(f => {
+      const links = [...(f.publication_links || [])]
+      const idx = links.findIndex(l => l.platform === platform)
+      if (idx >= 0) {
+        links[idx] = { ...links[idx], url }
+      } else {
+        links.push({ platform, url })
+      }
+      return { ...f, publication_links: links }
+    })
+  }
+
+  const openEdit = (post) => {
+    if (!canEditResource('post', post)) {
+      alert('You can only edit your own posts')
+      return
+    }
+    setEditingPost(post)
+    setPublishError('')
+    setFormData({
+      title: post.title || '',
+      description: post.description || '',
+      brand_id: post.brandId || post.brand_id || '',
+      platforms: post.platforms || (post.platform ? [post.platform] : []),
+      status: post.status || 'draft',
+      assigned_to: post.assignedTo || post.assigned_to || '',
+      scheduled_date: post.scheduledDate ? new Date(post.scheduledDate).toISOString().slice(0, 16) : '',
+      notes: post.notes || '',
+      campaign_id: post.campaignId || post.campaign_id || '',
+      publication_links: post.publication_links || post.publicationLinks || [],
+    })
+    loadAttachments(post._id || post.id)
+    setShowModal(true)
+  }
+
+  const openNew = () => {
+    setEditingPost(null)
+    setFormData(EMPTY_POST)
+    setAttachments([])
+    setPublishError('')
+    setShowModal(true)
+  }
+
+  const filteredPosts = posts.filter(p => {
+    if (filters.brand && String(p.brandId || p.brand_id) !== filters.brand) return false
+    if (filters.platform && !(p.platforms || []).includes(filters.platform) && p.platform !== filters.platform) return false
+    if (filters.assignedTo && String(p.assignedTo || p.assigned_to) !== filters.assignedTo) return false
+    if (filters.campaign && String(p.campaignId || p.campaign_id) !== filters.campaign) return false
+    if (searchTerm && !p.title?.toLowerCase().includes(searchTerm.toLowerCase())) return false
+    return true
+  })
+
+  if (loading) {
+    return (
+      <div className="space-y-4 animate-pulse">
+        <div className="h-12 bg-surface-tertiary rounded-xl"></div>
+        <div className="flex gap-4">
+          {[...Array(5)].map((_, i) => <div key={i} className="w-72 h-96 bg-surface-tertiary rounded-xl"></div>)}
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-4 animate-fade-in">
+      {/* Toolbar */}
+      <div className="flex flex-wrap items-center gap-3">
+        {/* Search */}
+        <div className="relative flex-1 min-w-[200px] max-w-md">
+          <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-text-tertiary" />
+          <input
+            type="text"
+            placeholder={t('posts.searchPosts')}
+            value={searchTerm}
+            onChange={e => setSearchTerm(e.target.value)}
+            className="w-full pl-10 pr-4 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary bg-white"
+          />
+        </div>
+
+        {/* Filters */}
+        <div data-tutorial="filters" className="flex gap-3">
+          <select
+            value={filters.brand}
+            onChange={e => setFilters(f => ({ ...f, brand: e.target.value }))}
+            className="text-sm border border-border rounded-lg px-3 py-2 bg-white text-text-secondary focus:outline-none focus:ring-2 focus:ring-brand-primary/20"
+          >
+            <option value="">{t('posts.allBrands')}</option>
+            {brands.map(b => <option key={b._id} value={b._id}>{b.name}</option>)}
+          </select>
+
+          <select
+            value={filters.platform}
+            onChange={e => setFilters(f => ({ ...f, platform: e.target.value }))}
+            className="text-sm border border-border rounded-lg px-3 py-2 bg-white text-text-secondary focus:outline-none focus:ring-2 focus:ring-brand-primary/20"
+          >
+            <option value="">{t('posts.allPlatforms')}</option>
+            {Object.entries(PLATFORMS).map(([k, v]) => <option key={k} value={k}>{v.label}</option>)}
+          </select>
+
+          <select
+            value={filters.assignedTo}
+            onChange={e => setFilters(f => ({ ...f, assignedTo: e.target.value }))}
+            className="text-sm border border-border rounded-lg px-3 py-2 bg-white text-text-secondary focus:outline-none focus:ring-2 focus:ring-brand-primary/20"
+          >
+            <option value="">{t('posts.allPeople')}</option>
+            {teamMembers.map(m => <option key={m._id} value={String(m._id)}>{m.name}</option>)}
+          </select>
+        </div>
+
+        {/* View toggle */}
+        <div className="flex bg-surface-tertiary rounded-lg p-0.5 ml-auto">
+          <button
+            onClick={() => setView('kanban')}
+            className={`p-2 rounded-md ${view === 'kanban' ? 'bg-white shadow-sm text-text-primary' : 'text-text-tertiary'}`}
+          >
+            <LayoutGrid className="w-4 h-4" />
+          </button>
+          <button
+            onClick={() => setView('list')}
+            className={`p-2 rounded-md ${view === 'list' ? 'bg-white shadow-sm text-text-primary' : 'text-text-tertiary'}`}
+          >
+            <List className="w-4 h-4" />
+          </button>
+        </div>
+
+        {/* New post */}
+        <button
+          data-tutorial="new-post"
+          onClick={openNew}
+          className="flex items-center gap-2 px-4 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm"
+        >
+          <Plus className="w-4 h-4" />
+          {t('posts.newPost')}
+        </button>
+      </div>
+
+      {/* Content */}
+      {view === 'kanban' ? (
+        <KanbanBoard posts={filteredPosts} onPostClick={openEdit} onMovePost={handleMovePost} />
+      ) : (
+        <div className="bg-white rounded-xl border border-border overflow-hidden">
+          <table className="w-full">
+            <thead>
+              <tr className="border-b border-border bg-surface-secondary">
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">{t('posts.postTitle')}</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">{t('posts.brand')}</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">{t('posts.status')}</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">{t('posts.platforms')}</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">{t('posts.assignTo')}</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">{t('posts.scheduledDate')}</th>
+              </tr>
+            </thead>
+            <tbody className="divide-y divide-border-light">
+              {filteredPosts.map(post => (
+                <PostCard key={post._id} post={post} onClick={() => openEdit(post)} />
+              ))}
+              {filteredPosts.length === 0 && (
+                <tr>
+                  <td colSpan={6} className="py-12 text-center text-sm text-text-tertiary">
+                    {t('posts.noPostsFound')}
+                  </td>
+                </tr>
+              )}
+            </tbody>
+          </table>
+        </div>
+      )}
+
+      {/* Create/Edit Modal */}
+      <Modal
+        isOpen={showModal}
+        onClose={() => { setShowModal(false); setEditingPost(null) }}
+        title={editingPost ? t('posts.editPost') : t('posts.createPost')}
+        size="lg"
+      >
+        <div className="space-y-4">
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">{t('posts.postTitle')} *</label>
+            <input
+              type="text"
+              value={formData.title}
+              onChange={e => setFormData(f => ({ ...f, title: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder={t('posts.postTitlePlaceholder')}
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">{t('posts.description')}</label>
+            <textarea
+              value={formData.description}
+              onChange={e => setFormData(f => ({ ...f, description: e.target.value }))}
+              rows={4}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary resize-none"
+              placeholder={t('posts.postDescPlaceholder')}
+            />
+          </div>
+
+          {/* Campaign */}
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">{t('posts.campaign')}</label>
+            <select
+              value={formData.campaign_id}
+              onChange={e => setFormData(f => ({ ...f, campaign_id: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+            >
+              <option value="">{t('posts.noCampaign')}</option>
+              {campaigns.map(c => <option key={c._id} value={c._id}>{c.name}</option>)}
+            </select>
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('posts.brand')}</label>
+              <select
+                value={formData.brand_id}
+                onChange={e => setFormData(f => ({ ...f, brand_id: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              >
+                <option value="">{t('posts.selectBrand')}</option>
+                {brands.map(b => <option key={b._id} value={b._id}>{b.icon} {b.name}</option>)}
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('posts.platforms')}</label>
+              <div className="flex flex-wrap gap-2 p-2 border border-border rounded-lg bg-white min-h-[42px]">
+                {Object.entries(PLATFORMS).map(([k, v]) => {
+                  const checked = (formData.platforms || []).includes(k)
+                  return (
+                    <label
+                      key={k}
+                      className={`flex items-center gap-1.5 text-xs px-2.5 py-1.5 rounded-full cursor-pointer border transition-colors ${
+                        checked
+                          ? 'bg-brand-primary/10 border-brand-primary/30 text-brand-primary font-medium'
+                          : 'bg-surface-tertiary border-transparent text-text-secondary hover:bg-surface-tertiary/80'
+                      }`}
+                    >
+                      <input
+                        type="checkbox"
+                        checked={checked}
+                        onChange={() => {
+                          setFormData(f => ({
+                            ...f,
+                            platforms: checked
+                              ? f.platforms.filter(p => p !== k)
+                              : [...(f.platforms || []), k]
+                          }))
+                        }}
+                        className="sr-only"
+                      />
+                      {v.label}
+                    </label>
+                  )
+                })}
+              </div>
+            </div>
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('posts.status')}</label>
+              <select
+                value={formData.status}
+                onChange={e => setFormData(f => ({ ...f, status: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              >
+                <option value="draft">{t('posts.status.draft')}</option>
+                <option value="in_review">{t('posts.status.in_review')}</option>
+                <option value="approved">{t('posts.status.approved')}</option>
+                <option value="scheduled">{t('posts.status.scheduled')}</option>
+                <option value="published">{t('posts.status.published')}</option>
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('posts.assignTo')}</label>
+              <select
+                value={formData.assigned_to}
+                onChange={e => setFormData(f => ({ ...f, assigned_to: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              >
+                <option value="">{t('common.unassigned')}</option>
+                {teamMembers.map(m => <option key={m._id} value={m._id}>{m.name}</option>)}
+              </select>
+            </div>
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('posts.scheduledDate')}</label>
+              <input
+                type="datetime-local"
+                value={formData.scheduled_date}
+                onChange={e => setFormData(f => ({ ...f, scheduled_date: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              />
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('posts.notes')}</label>
+              <input
+                type="text"
+                value={formData.notes}
+                onChange={e => setFormData(f => ({ ...f, notes: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                placeholder={t('posts.additionalNotes')}
+              />
+            </div>
+          </div>
+
+          {/* Publication Links */}
+          {(formData.platforms || []).length > 0 && (
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-2">
+                <span className="flex items-center gap-1.5">
+                  <Link2 className="w-4 h-4" />
+                  {t('posts.publicationLinks')}
+                </span>
+              </label>
+              <div className="space-y-2 border border-border rounded-lg p-3 bg-surface-secondary">
+                {(formData.platforms || []).map(platformKey => {
+                  const platformInfo = PLATFORMS[platformKey] || { label: platformKey }
+                  const existingLink = (formData.publication_links || []).find(l => l.platform === platformKey)
+                  const linkUrl = existingLink?.url || ''
+                  return (
+                    <div key={platformKey} className="flex items-center gap-2">
+                      <span className="text-xs font-medium text-text-secondary w-24 shrink-0 flex items-center gap-1.5">
+                        <span className="w-2 h-2 rounded-full shrink-0" style={{ backgroundColor: platformInfo.color || '#888' }} />
+                        {platformInfo.label}
+                      </span>
+                      <input
+                        type="url"
+                        value={linkUrl}
+                        onChange={e => updatePublicationLink(platformKey, e.target.value)}
+                        className="flex-1 px-3 py-1.5 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                        placeholder="https://..."
+                      />
+                      {linkUrl && (
+                        <a href={linkUrl} target="_blank" rel="noopener noreferrer" className="p-1.5 text-text-tertiary hover:text-brand-primary">
+                          <ExternalLink className="w-3.5 h-3.5" />
+                        </a>
+                      )}
+                    </div>
+                  )
+                })}
+                {formData.status === 'published' && (formData.platforms || []).some(p => {
+                  const link = (formData.publication_links || []).find(l => l.platform === p)
+                  return !link || !link.url?.trim()
+                }) && (
+                  <p className="text-xs text-amber-600 mt-1">⚠️ {t('posts.publishRequired')}</p>
+                )}
+              </div>
+            </div>
+          )}
+
+          {/* Attachments (only for existing posts) */}
+          {editingPost && (
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-2">
+                <span className="flex items-center gap-1.5">
+                  <Paperclip className="w-4 h-4" />
+                  {t('posts.attachments')}
+                  <span className="text-xs text-text-tertiary font-normal">({attachments.length})</span>
+                </span>
+              </label>
+
+              {/* Existing attachments */}
+              {attachments.length > 0 && (
+                <div className="grid grid-cols-2 sm:grid-cols-3 gap-2 mb-3">
+                  {attachments.map(att => {
+                    const isImage = att.mime_type?.startsWith('image/') || att.mimeType?.startsWith('image/')
+                    const attUrl = att.url || `/api/uploads/${att.filename}`
+                    const name = att.original_name || att.originalName || att.filename
+                    return (
+                      <div key={att.id || att._id} className="relative group/att border border-border rounded-lg overflow-hidden bg-white">
+                        {isImage ? (
+                          <a href={`http://localhost:3001${attUrl}`} target="_blank" rel="noopener noreferrer">
+                            <img
+                              src={`http://localhost:3001${attUrl}`}
+                              alt={name}
+                              className="w-full h-24 object-cover"
+                            />
+                          </a>
+                        ) : (
+                          <a href={`http://localhost:3001${attUrl}`} target="_blank" rel="noopener noreferrer" className="flex items-center gap-2 p-3 h-24">
+                            <FileText className="w-8 h-8 text-text-tertiary shrink-0" />
+                            <span className="text-xs text-text-secondary truncate">{name}</span>
+                          </a>
+                        )}
+                        <button
+                          onClick={() => handleDeleteAttachment(att.id || att._id)}
+                          className="absolute top-1 right-1 p-1 bg-red-500 text-white rounded-full opacity-0 group-hover/att:opacity-100 transition-opacity shadow-sm"
+                          title={t('posts.deleteAttachment')}
+                        >
+                          <X className="w-3 h-3" />
+                        </button>
+                        <div className="px-2 py-1 text-[10px] text-text-tertiary truncate border-t border-border-light">
+                          {name}
+                        </div>
+                      </div>
+                    )
+                  })}
+                </div>
+              )}
+
+              {/* Upload area */}
+              <div
+                className={`border-2 border-dashed rounded-lg p-4 text-center cursor-pointer transition-colors ${
+                  dragActive ? 'border-brand-primary bg-brand-primary/5' : 'border-border hover:border-brand-primary/40'
+                }`}
+                onClick={() => fileInputRef.current?.click()}
+                onDragEnter={handleDragEnter}
+                onDragLeave={handleDragLeaveZone}
+                onDragOver={handleDragOverZone}
+                onDrop={handleDropFiles}
+              >
+                <input
+                  ref={fileInputRef}
+                  type="file"
+                  multiple
+                  className="hidden"
+                  onChange={(e) => handleFileUpload(e.target.files)}
+                />
+                <Upload className="w-6 h-6 text-text-tertiary mx-auto mb-1" />
+                <p className="text-xs text-text-secondary">
+                  {dragActive ? t('posts.dropFiles') : t('posts.uploadFiles')}
+                </p>
+                <p className="text-[10px] text-text-tertiary mt-0.5">{t('posts.maxSize')}</p>
+              </div>
+
+              {/* Upload progress */}
+              {uploading && (
+                <div className="mt-2">
+                  <div className="flex items-center justify-between text-xs text-text-secondary mb-1">
+                    <span>{t('posts.uploading')}</span>
+                    <span>{uploadProgress}%</span>
+                  </div>
+                  <div className="w-full bg-surface-tertiary rounded-full h-1.5">
+                    <div
+                      className="bg-brand-primary h-1.5 rounded-full transition-all"
+                      style={{ width: `${uploadProgress}%` }}
+                    />
+                  </div>
+                </div>
+              )}
+            </div>
+          )}
+
+          {/* Publish validation error */}
+          {publishError && (
+            <div className="p-3 bg-red-50 border border-red-200 rounded-lg text-sm text-red-700">
+              {publishError}
+            </div>
+          )}
+
+          {/* Actions */}
+          <div className="flex items-center justify-end gap-3 pt-4 border-t border-border">
+            {editingPost && canDeleteResource('post', editingPost) && (
+              <button
+                onClick={() => setShowDeleteConfirm(true)}
+                className="px-4 py-2 text-sm font-medium text-red-600 hover:bg-red-50 rounded-lg mr-auto"
+              >
+                {t('common.delete')}
+              </button>
+            )}
+            <button
+              onClick={() => { setShowModal(false); setEditingPost(null) }}
+              className="px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg"
+            >
+              {t('common.cancel')}
+            </button>
+            <button
+              onClick={handleSave}
+              disabled={!formData.title}
+              className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm"
+            >
+              {editingPost ? t('posts.saveChanges') : t('posts.createPost')}
+            </button>
+          </div>
+        </div>
+      </Modal>
+
+      {/* Delete Confirmation */}
+      <Modal
+        isOpen={showDeleteConfirm}
+        onClose={() => setShowDeleteConfirm(false)}
+        title={t('posts.deletePost')}
+        isConfirm
+        danger
+        confirmText={t('posts.deletePost')}
+        onConfirm={async () => {
+          if (editingPost) {
+            try {
+              await api.delete(`/posts/${editingPost._id || editingPost.id}`)
+              setShowModal(false)
+              setEditingPost(null)
+              loadPosts()
+            } catch (err) {
+              console.error('Delete failed:', err)
+            }
+          }
+        }}
+      >
+        {t('posts.deleteConfirm')}
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/pages/ProjectDetail.jsx b/client/src/pages/ProjectDetail.jsx
new file mode 100644
index 0000000..41615b9
--- /dev/null
+++ b/client/src/pages/ProjectDetail.jsx
@@ -0,0 +1,777 @@
+import { useState, useEffect, useContext } from 'react'
+import { useParams, useNavigate } from 'react-router-dom'
+import {
+  ArrowLeft, Plus, Check, Trash2, Edit3, LayoutGrid, List,
+  GanttChart, Settings, Calendar, Clock
+} from 'lucide-react'
+import { format, differenceInDays, startOfDay, addDays, isAfter, isBefore, parseISO } from 'date-fns'
+import { AppContext } from '../App'
+import { api, PRIORITY_CONFIG } from '../utils/api'
+import StatusBadge from '../components/StatusBadge'
+import BrandBadge from '../components/BrandBadge'
+import Modal from '../components/Modal'
+
+const TASK_COLUMNS = [
+  { id: 'todo', label: 'To Do', color: 'bg-gray-400' },
+  { id: 'in_progress', label: 'In Progress', color: 'bg-blue-400' },
+  { id: 'done', label: 'Done', color: 'bg-emerald-400' },
+]
+
+export default function ProjectDetail() {
+  const { id } = useParams()
+  const navigate = useNavigate()
+  const { teamMembers, brands } = useContext(AppContext)
+  const [project, setProject] = useState(null)
+  const [tasks, setTasks] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [view, setView] = useState('kanban')
+  const [showTaskModal, setShowTaskModal] = useState(false)
+  const [showProjectModal, setShowProjectModal] = useState(false)
+  const [editingTask, setEditingTask] = useState(null)
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+  const [taskToDelete, setTaskToDelete] = useState(null)
+  const [taskForm, setTaskForm] = useState({
+    title: '', description: '', priority: 'medium', assigned_to: '', due_date: '', status: 'todo'
+  })
+  const [projectForm, setProjectForm] = useState({
+    name: '', description: '', brand_id: '', owner_id: '', status: 'active', due_date: ''
+  })
+
+  // Drag state for kanban
+  const [draggedTask, setDraggedTask] = useState(null)
+  const [dragOverCol, setDragOverCol] = useState(null)
+
+  useEffect(() => { loadProject() }, [id])
+
+  const loadProject = async () => {
+    try {
+      const proj = await api.get(`/projects/${id}`)
+      setProject(proj.data || proj)
+      const tasksRes = await api.get(`/tasks?project_id=${id}`)
+      setTasks(Array.isArray(tasksRes) ? tasksRes : (tasksRes.data || []))
+    } catch (err) {
+      console.error('Failed to load project:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleTaskSave = async () => {
+    try {
+      const data = {
+        title: taskForm.title,
+        description: taskForm.description,
+        priority: taskForm.priority,
+        assigned_to: taskForm.assigned_to ? Number(taskForm.assigned_to) : null,
+        due_date: taskForm.due_date || null,
+        status: taskForm.status,
+        project_id: Number(id),
+      }
+      if (editingTask) {
+        await api.patch(`/tasks/${editingTask._id}`, data)
+      } else {
+        await api.post('/tasks', data)
+      }
+      setShowTaskModal(false)
+      setEditingTask(null)
+      setTaskForm({ title: '', description: '', priority: 'medium', assigned_to: '', due_date: '', status: 'todo' })
+      loadProject()
+    } catch (err) {
+      console.error('Task save failed:', err)
+    }
+  }
+
+  const handleTaskStatusChange = async (taskId, newStatus) => {
+    try {
+      await api.patch(`/tasks/${taskId}`, { status: newStatus })
+      loadProject()
+    } catch (err) {
+      console.error('Status change failed:', err)
+    }
+  }
+
+  const handleDeleteTask = async (taskId) => {
+    setTaskToDelete(taskId)
+    setShowDeleteConfirm(true)
+  }
+
+  const confirmDeleteTask = async () => {
+    if (!taskToDelete) return
+    try {
+      await api.delete(`/tasks/${taskToDelete}`)
+      loadProject()
+      setTaskToDelete(null)
+    } catch (err) {
+      console.error('Delete failed:', err)
+    }
+  }
+
+  const openEditTask = (task) => {
+    setEditingTask(task)
+    setTaskForm({
+      title: task.title || '',
+      description: task.description || '',
+      priority: task.priority || 'medium',
+      assigned_to: task.assignedTo || task.assigned_to || '',
+      due_date: task.dueDate ? new Date(task.dueDate).toISOString().slice(0, 10) : '',
+      status: task.status || 'todo',
+    })
+    setShowTaskModal(true)
+  }
+
+  const openNewTask = () => {
+    setEditingTask(null)
+    setTaskForm({ title: '', description: '', priority: 'medium', assigned_to: '', due_date: '', status: 'todo' })
+    setShowTaskModal(true)
+  }
+
+  const openEditProject = () => {
+    if (!project) return
+    setProjectForm({
+      name: project.name || '',
+      description: project.description || '',
+      brand_id: project.brandId || project.brand_id || '',
+      owner_id: project.ownerId || project.owner_id || '',
+      status: project.status || 'active',
+      due_date: project.dueDate ? new Date(project.dueDate).toISOString().slice(0, 10) : '',
+    })
+    setShowProjectModal(true)
+  }
+
+  const handleProjectSave = async () => {
+    try {
+      await api.patch(`/projects/${id}`, {
+        name: projectForm.name,
+        description: projectForm.description,
+        brand_id: projectForm.brand_id ? Number(projectForm.brand_id) : null,
+        owner_id: projectForm.owner_id ? Number(projectForm.owner_id) : null,
+        status: projectForm.status,
+        due_date: projectForm.due_date || null,
+      })
+      setShowProjectModal(false)
+      loadProject()
+    } catch (err) {
+      console.error('Project save failed:', err)
+    }
+  }
+
+  // Drag handlers
+  const handleDragStart = (e, task) => {
+    setDraggedTask(task)
+    e.dataTransfer.effectAllowed = 'move'
+    setTimeout(() => { e.target.style.opacity = '0.4' }, 0)
+  }
+  const handleDragEnd = (e) => {
+    e.target.style.opacity = '1'
+    setDraggedTask(null)
+    setDragOverCol(null)
+  }
+  const handleDragOver = (e, colId) => {
+    e.preventDefault()
+    e.dataTransfer.dropEffect = 'move'
+    setDragOverCol(colId)
+  }
+  const handleDragLeave = (e) => {
+    if (!e.currentTarget.contains(e.relatedTarget)) setDragOverCol(null)
+  }
+  const handleDrop = (e, colId) => {
+    e.preventDefault()
+    setDragOverCol(null)
+    if (draggedTask && draggedTask.status !== colId) {
+      handleTaskStatusChange(draggedTask._id, colId)
+    }
+    setDraggedTask(null)
+  }
+
+  if (loading) {
+    return (
+      <div className="animate-pulse space-y-4">
+        <div className="h-8 w-48 bg-surface-tertiary rounded-lg"></div>
+        <div className="h-40 bg-surface-tertiary rounded-xl"></div>
+      </div>
+    )
+  }
+
+  if (!project) {
+    return (
+      <div className="py-20 text-center">
+        <p className="text-text-secondary">Project not found</p>
+        <button onClick={() => navigate('/projects')} className="mt-4 text-brand-primary hover:underline text-sm">
+          Back to Projects
+        </button>
+      </div>
+    )
+  }
+
+  const completedTasks = tasks.filter(t => t.status === 'done').length
+  const progress = tasks.length > 0 ? Math.round((completedTasks / tasks.length) * 100) : 0
+  const ownerName = project.ownerName || project.owner_name
+  const brandName = project.brandName || project.brand_name
+
+  // Gantt chart helpers
+  const getGanttRange = () => {
+    const today = startOfDay(new Date())
+    let earliest = today
+    let latest = addDays(today, 14)
+
+    tasks.forEach(t => {
+      if (t.createdAt) {
+        const d = startOfDay(new Date(t.createdAt))
+        if (isBefore(d, earliest)) earliest = d
+      }
+      if (t.dueDate) {
+        const d = startOfDay(new Date(t.dueDate))
+        if (isAfter(d, latest)) latest = addDays(d, 1)
+      }
+    })
+    if (project.dueDate) {
+      const d = startOfDay(new Date(project.dueDate))
+      if (isAfter(d, latest)) latest = addDays(d, 1)
+    }
+    // Ensure minimum 14 days
+    if (differenceInDays(latest, earliest) < 14) latest = addDays(earliest, 14)
+    return { earliest, latest, totalDays: differenceInDays(latest, earliest) + 1 }
+  }
+
+  return (
+    <div className="space-y-6 animate-fade-in">
+      {/* Back button */}
+      <button
+        onClick={() => navigate('/projects')}
+        className="flex items-center gap-2 text-sm text-text-secondary hover:text-text-primary transition-colors"
+      >
+        <ArrowLeft className="w-4 h-4" />
+        Back to Projects
+      </button>
+
+      {/* Project header */}
+      <div className="bg-white rounded-xl border border-border p-6">
+        <div className="flex items-start justify-between gap-4 mb-4">
+          <div>
+            <div className="flex items-center gap-3 mb-2">
+              <h1 className="text-2xl font-bold text-text-primary">{project.name}</h1>
+              <StatusBadge status={project.status} />
+            </div>
+            <div className="flex items-center gap-3 flex-wrap">
+              {brandName && <BrandBadge brand={brandName} />}
+              {ownerName && (
+                <span className="text-sm text-text-secondary">
+                  Owned by <span className="font-medium">{ownerName}</span>
+                </span>
+              )}
+              {project.dueDate && (
+                <span className="text-sm text-text-tertiary flex items-center gap-1">
+                  <Calendar className="w-3.5 h-3.5" />
+                  Due {format(new Date(project.dueDate), 'MMMM d, yyyy')}
+                </span>
+              )}
+            </div>
+          </div>
+          <button
+            onClick={openEditProject}
+            className="flex items-center gap-1.5 px-3 py-1.5 text-sm font-medium text-text-secondary hover:text-text-primary hover:bg-surface-tertiary rounded-lg transition-colors"
+          >
+            <Settings className="w-4 h-4" />
+            Edit
+          </button>
+        </div>
+
+        {project.description && (
+          <p className="text-sm text-text-secondary mb-4">{project.description}</p>
+        )}
+
+        {/* Progress */}
+        <div className="max-w-md">
+          <div className="flex items-center justify-between text-sm mb-2">
+            <span className="text-text-secondary font-medium">Progress</span>
+            <span className="font-semibold text-text-primary">{progress}%</span>
+          </div>
+          <div className="h-2.5 bg-surface-tertiary rounded-full overflow-hidden">
+            <div
+              className="h-full bg-gradient-to-r from-brand-primary to-brand-primary-light rounded-full transition-all duration-500"
+              style={{ width: `${progress}%` }}
+            />
+          </div>
+          <p className="text-xs text-text-tertiary mt-1">{completedTasks} of {tasks.length} tasks completed</p>
+        </div>
+      </div>
+
+      {/* View switcher + Add Task */}
+      <div className="flex items-center justify-between">
+        <div className="flex items-center gap-1 bg-surface-tertiary rounded-lg p-0.5">
+          {[
+            { id: 'kanban', icon: LayoutGrid, label: 'Board' },
+            { id: 'list', icon: List, label: 'List' },
+            { id: 'gantt', icon: GanttChart, label: 'Timeline' },
+          ].map(v => (
+            <button
+              key={v.id}
+              onClick={() => setView(v.id)}
+              className={`flex items-center gap-1.5 px-3 py-1.5 rounded-md text-sm font-medium transition-colors ${
+                view === v.id ? 'bg-white shadow-sm text-text-primary' : 'text-text-tertiary hover:text-text-secondary'
+              }`}
+            >
+              <v.icon className="w-4 h-4" />
+              {v.label}
+            </button>
+          ))}
+        </div>
+        <button
+          onClick={openNewTask}
+          className="flex items-center gap-2 px-4 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm"
+        >
+          <Plus className="w-4 h-4" />
+          Add Task
+        </button>
+      </div>
+
+      {/* ─── KANBAN VIEW ─── */}
+      {view === 'kanban' && (
+        <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
+          {TASK_COLUMNS.map(col => {
+            const colTasks = tasks.filter(t => t.status === col.id)
+            const isOver = dragOverCol === col.id && draggedTask?.status !== col.id
+            return (
+              <div key={col.id}>
+                <div className="flex items-center gap-2 mb-3">
+                  <div className={`w-2.5 h-2.5 rounded-full ${col.color}`} />
+                  <h4 className="text-sm font-semibold text-text-primary">{col.label}</h4>
+                  <span className="text-xs font-medium text-text-tertiary bg-surface-tertiary px-2 py-0.5 rounded-full">
+                    {colTasks.length}
+                  </span>
+                </div>
+                <div
+                  className={`rounded-xl p-2 space-y-2 min-h-[150px] border-2 transition-colors ${
+                    isOver
+                      ? 'bg-brand-primary/5 border-brand-primary/40 border-dashed'
+                      : 'bg-surface-secondary border-border-light border-solid'
+                  }`}
+                  onDragOver={(e) => handleDragOver(e, col.id)}
+                  onDragLeave={handleDragLeave}
+                  onDrop={(e) => handleDrop(e, col.id)}
+                >
+                  {colTasks.length === 0 ? (
+                    <div className={`py-8 text-center text-xs ${isOver ? 'text-brand-primary font-medium' : 'text-text-tertiary'}`}>
+                      {isOver ? 'Drop here' : 'No tasks'}
+                    </div>
+                  ) : (
+                    colTasks.map(task => (
+                      <TaskKanbanCard
+                        key={task._id}
+                        task={task}
+                        onEdit={() => openEditTask(task)}
+                        onDelete={() => handleDeleteTask(task._id)}
+                        onStatusChange={handleTaskStatusChange}
+                        onDragStart={handleDragStart}
+                        onDragEnd={handleDragEnd}
+                      />
+                    ))
+                  )}
+                </div>
+              </div>
+            )
+          })}
+        </div>
+      )}
+
+      {/* ─── LIST VIEW ─── */}
+      {view === 'list' && (
+        <div className="bg-white rounded-xl border border-border overflow-hidden">
+          <table className="w-full">
+            <thead>
+              <tr className="border-b border-border bg-surface-secondary">
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider w-8"></th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">Task</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">Status</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">Priority</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">Assignee</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">Due</th>
+                <th className="text-left px-4 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider w-16"></th>
+              </tr>
+            </thead>
+            <tbody className="divide-y divide-border-light">
+              {tasks.length === 0 ? (
+                <tr><td colSpan={7} className="py-12 text-center text-sm text-text-tertiary">No tasks yet</td></tr>
+              ) : (
+                tasks.map(task => {
+                  const prio = PRIORITY_CONFIG[task.priority] || PRIORITY_CONFIG.medium
+                  const assigneeName = task.assignedName || task.assigned_name
+                  const isOverdue = task.dueDate && new Date(task.dueDate) < new Date() && task.status !== 'done'
+                  return (
+                    <tr key={task._id} className="hover:bg-surface-secondary group">
+                      <td className="px-4 py-3">
+                        <div className={`w-2.5 h-2.5 rounded-full ${prio.color}`} />
+                      </td>
+                      <td className="px-4 py-3">
+                        <button onClick={() => openEditTask(task)} className="text-sm font-medium text-text-primary hover:text-brand-primary text-left">
+                          {task.title}
+                        </button>
+                        {task.description && <p className="text-xs text-text-tertiary line-clamp-1 mt-0.5">{task.description}</p>}
+                      </td>
+                      <td className="px-4 py-3"><StatusBadge status={task.status} size="xs" /></td>
+                      <td className="px-4 py-3 text-xs font-medium text-text-secondary capitalize">{prio.label}</td>
+                      <td className="px-4 py-3 text-xs text-text-secondary">{assigneeName || '—'}</td>
+                      <td className={`px-4 py-3 text-xs ${isOverdue ? 'text-red-500 font-medium' : 'text-text-tertiary'}`}>
+                        {task.dueDate ? format(new Date(task.dueDate), 'MMM d, yyyy') : '—'}
+                      </td>
+                      <td className="px-4 py-3">
+                        <div className="flex items-center gap-1 opacity-0 group-hover:opacity-100 transition-opacity">
+                          <button onClick={() => openEditTask(task)} className="p-1 rounded hover:bg-surface-tertiary text-text-tertiary">
+                            <Edit3 className="w-3.5 h-3.5" />
+                          </button>
+                          <button onClick={() => handleDeleteTask(task._id)} className="p-1 rounded hover:bg-red-50 text-red-400">
+                            <Trash2 className="w-3.5 h-3.5" />
+                          </button>
+                        </div>
+                      </td>
+                    </tr>
+                  )
+                })
+              )}
+            </tbody>
+          </table>
+        </div>
+      )}
+
+      {/* ─── GANTT / TIMELINE VIEW ─── */}
+      {view === 'gantt' && <GanttView tasks={tasks} project={project} onEditTask={openEditTask} />}
+
+      {/* ─── TASK MODAL ─── */}
+      <Modal
+        isOpen={showTaskModal}
+        onClose={() => { setShowTaskModal(false); setEditingTask(null) }}
+        title={editingTask ? 'Edit Task' : 'Add Task'}
+        size="md"
+      >
+        <div className="space-y-4">
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Title *</label>
+            <input
+              type="text"
+              value={taskForm.title}
+              onChange={e => setTaskForm(f => ({ ...f, title: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder="Task title"
+            />
+          </div>
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Description</label>
+            <textarea
+              value={taskForm.description}
+              onChange={e => setTaskForm(f => ({ ...f, description: e.target.value }))}
+              rows={2}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary resize-none"
+              placeholder="Optional description"
+            />
+          </div>
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Priority</label>
+              <select value={taskForm.priority} onChange={e => setTaskForm(f => ({ ...f, priority: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary">
+                <option value="low">Low</option>
+                <option value="medium">Medium</option>
+                <option value="high">High</option>
+                <option value="urgent">Urgent</option>
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Status</label>
+              <select value={taskForm.status} onChange={e => setTaskForm(f => ({ ...f, status: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary">
+                <option value="todo">To Do</option>
+                <option value="in_progress">In Progress</option>
+                <option value="done">Done</option>
+              </select>
+            </div>
+          </div>
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Assign To</label>
+              <select value={taskForm.assigned_to} onChange={e => setTaskForm(f => ({ ...f, assigned_to: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary">
+                <option value="">Unassigned</option>
+                {teamMembers.map(m => <option key={m._id} value={m._id}>{m.name}</option>)}
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Due Date</label>
+              <input type="date" value={taskForm.due_date} onChange={e => setTaskForm(f => ({ ...f, due_date: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary" />
+            </div>
+          </div>
+          <div className="flex items-center justify-end gap-3 pt-4 border-t border-border">
+            {editingTask && (
+              <button onClick={() => handleDeleteTask(editingTask._id)}
+                className="px-4 py-2 text-sm font-medium text-red-600 hover:bg-red-50 rounded-lg mr-auto">
+                Delete
+              </button>
+            )}
+            <button onClick={() => { setShowTaskModal(false); setEditingTask(null) }}
+              className="px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg">
+              Cancel
+            </button>
+            <button onClick={handleTaskSave} disabled={!taskForm.title}
+              className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm">
+              {editingTask ? 'Save Changes' : 'Add Task'}
+            </button>
+          </div>
+        </div>
+      </Modal>
+
+      {/* ─── PROJECT EDIT MODAL ─── */}
+      <Modal
+        isOpen={showProjectModal}
+        onClose={() => setShowProjectModal(false)}
+        title="Edit Project"
+        size="md"
+      >
+        <div className="space-y-4">
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Name *</label>
+            <input type="text" value={projectForm.name} onChange={e => setProjectForm(f => ({ ...f, name: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder="Project name" />
+          </div>
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Description</label>
+            <textarea value={projectForm.description} onChange={e => setProjectForm(f => ({ ...f, description: e.target.value }))}
+              rows={3} className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary resize-none"
+              placeholder="Project description..." />
+          </div>
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Brand</label>
+              <select value={projectForm.brand_id} onChange={e => setProjectForm(f => ({ ...f, brand_id: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary">
+                <option value="">Select brand</option>
+                {brands.map(b => <option key={b._id} value={b._id}>{b.icon} {b.name}</option>)}
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Status</label>
+              <select value={projectForm.status} onChange={e => setProjectForm(f => ({ ...f, status: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary">
+                <option value="active">Active</option>
+                <option value="paused">Paused</option>
+                <option value="completed">Completed</option>
+                <option value="cancelled">Cancelled</option>
+              </select>
+            </div>
+          </div>
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Owner</label>
+              <select value={projectForm.owner_id} onChange={e => setProjectForm(f => ({ ...f, owner_id: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary">
+                <option value="">Unassigned</option>
+                {teamMembers.map(m => <option key={m._id} value={m._id}>{m.name}</option>)}
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Due Date</label>
+              <input type="date" value={projectForm.due_date} onChange={e => setProjectForm(f => ({ ...f, due_date: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary" />
+            </div>
+          </div>
+          <div className="flex items-center justify-end gap-3 pt-4 border-t border-border">
+            <button onClick={() => setShowProjectModal(false)}
+              className="px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg">
+              Cancel
+            </button>
+            <button onClick={handleProjectSave} disabled={!projectForm.name}
+              className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm">
+              Save Changes
+            </button>
+          </div>
+        </div>
+      </Modal>
+    </div>
+  )
+}
+
+// ─── Task Kanban Card ───────────────────────────────
+function TaskKanbanCard({ task, onEdit, onDelete, onStatusChange, onDragStart, onDragEnd }) {
+  const priority = PRIORITY_CONFIG[task.priority] || PRIORITY_CONFIG.medium
+  const assigneeName = task.assignedName || task.assigned_name
+  const isOverdue = task.dueDate && new Date(task.dueDate) < new Date() && task.status !== 'done'
+
+  return (
+    <div
+      draggable
+      onDragStart={(e) => onDragStart(e, task)}
+      onDragEnd={onDragEnd}
+      className="bg-white rounded-lg border border-border p-3 group hover:border-brand-primary/30 hover:shadow-sm transition-all cursor-grab active:cursor-grabbing"
+    >
+      <div className="flex items-start gap-2">
+        <div className={`w-2 h-2 rounded-full ${priority.color} mt-1.5 shrink-0`} title={priority.label} />
+        <div className="flex-1 min-w-0">
+          <h5 className={`text-sm font-medium ${task.status === 'done' ? 'text-text-tertiary line-through' : 'text-text-primary'}`}>
+            {task.title}
+          </h5>
+          <div className="flex items-center gap-2 mt-1.5 flex-wrap">
+            {assigneeName && (
+              <span className="text-[10px] text-text-tertiary">{assigneeName}</span>
+            )}
+            {task.dueDate && (
+              <span className={`text-[10px] flex items-center gap-0.5 ${isOverdue ? 'text-red-500 font-medium' : 'text-text-tertiary'}`}>
+                <Clock className="w-3 h-3" />
+                {format(new Date(task.dueDate), 'MMM d')}
+              </span>
+            )}
+          </div>
+        </div>
+      </div>
+      {/* Actions on hover */}
+      <div className="flex items-center gap-1 mt-2 pt-2 border-t border-border-light opacity-0 group-hover:opacity-100 transition-opacity">
+        {task.status !== 'done' && (
+          <button onClick={() => onStatusChange(task._id, task.status === 'todo' ? 'in_progress' : 'done')}
+            className="text-[10px] text-brand-primary hover:bg-brand-primary/10 px-2 py-0.5 rounded-full flex items-center gap-1">
+            <Check className="w-3 h-3" />
+            {task.status === 'todo' ? 'Start' : 'Complete'}
+          </button>
+        )}
+        <button onClick={onEdit}
+          className="text-[10px] text-text-tertiary hover:bg-surface-tertiary px-2 py-0.5 rounded-full flex items-center gap-1">
+          <Edit3 className="w-3 h-3" /> Edit
+        </button>
+        <button onClick={onDelete}
+          className="text-[10px] text-red-400 hover:bg-red-50 px-2 py-0.5 rounded-full flex items-center gap-1 ml-auto">
+          <Trash2 className="w-3 h-3" />
+        </button>
+      </div>
+    </div>
+  )
+}
+
+// ─── Gantt / Timeline View ──────────────────────────
+function GanttView({ tasks, project, onEditTask }) {
+  if (tasks.length === 0) {
+    return (
+      <div className="bg-white rounded-xl border border-border py-16 text-center">
+        <GanttChart className="w-12 h-12 text-text-tertiary mx-auto mb-3" />
+        <p className="text-text-secondary font-medium">No tasks to display</p>
+        <p className="text-sm text-text-tertiary mt-1">Add tasks with due dates to see the timeline</p>
+      </div>
+    )
+  }
+
+  const today = startOfDay(new Date())
+
+  // Calculate range
+  let earliest = today
+  let latest = addDays(today, 21)
+  tasks.forEach(t => {
+    const created = t.createdAt ? startOfDay(new Date(t.createdAt)) : today
+    const due = t.dueDate ? startOfDay(new Date(t.dueDate)) : null
+    if (isBefore(created, earliest)) earliest = created
+    if (due && isAfter(due, latest)) latest = addDays(due, 2)
+  })
+  if (project.dueDate) {
+    const pd = startOfDay(new Date(project.dueDate))
+    if (isAfter(pd, latest)) latest = addDays(pd, 2)
+  }
+  const totalDays = differenceInDays(latest, earliest) + 1
+
+  // Generate day headers
+  const days = []
+  for (let i = 0; i < totalDays; i++) {
+    days.push(addDays(earliest, i))
+  }
+
+  const dayWidth = Math.max(36, Math.min(60, 800 / totalDays))
+
+  const getBarStyle = (task) => {
+    const start = task.createdAt ? startOfDay(new Date(task.createdAt)) : today
+    const end = task.dueDate ? startOfDay(new Date(task.dueDate)) : addDays(start, 3)
+    const left = differenceInDays(start, earliest) * dayWidth
+    const width = Math.max(dayWidth, (differenceInDays(end, start) + 1) * dayWidth)
+    return { left: `${left}px`, width: `${width}px` }
+  }
+
+  const statusColors = {
+    todo: 'bg-gray-300',
+    in_progress: 'bg-blue-400',
+    done: 'bg-emerald-400',
+  }
+
+  return (
+    <div className="bg-white rounded-xl border border-border overflow-hidden">
+      <div className="overflow-x-auto">
+        <div style={{ minWidth: `${totalDays * dayWidth + 200}px` }}>
+          {/* Day headers */}
+          <div className="flex border-b border-border bg-surface-secondary sticky top-0 z-10">
+            <div className="w-[200px] shrink-0 px-4 py-2 text-xs font-semibold text-text-tertiary uppercase border-r border-border">
+              Task
+            </div>
+            <div className="flex">
+              {days.map((day, i) => {
+                const isToday = differenceInDays(day, today) === 0
+                const isWeekend = day.getDay() === 0 || day.getDay() === 6
+                return (
+                  <div
+                    key={i}
+                    style={{ width: `${dayWidth}px` }}
+                    className={`text-center py-2 border-r border-border-light text-[10px] ${
+                      isToday ? 'bg-brand-primary/10 font-bold text-brand-primary' :
+                      isWeekend ? 'bg-surface-tertiary/50 text-text-tertiary' : 'text-text-tertiary'
+                    }`}
+                  >
+                    <div>{format(day, 'd')}</div>
+                    <div className="text-[8px] uppercase">{format(day, 'EEE')}</div>
+                  </div>
+                )
+              })}
+            </div>
+          </div>
+
+          {/* Task rows */}
+          {tasks.map(task => {
+            const prio = PRIORITY_CONFIG[task.priority] || PRIORITY_CONFIG.medium
+            const barStyle = getBarStyle(task)
+            return (
+              <div key={task._id} className="flex border-b border-border-light hover:bg-surface-secondary/50 group">
+                <div className="w-[200px] shrink-0 px-4 py-3 border-r border-border flex items-center gap-2">
+                  <div className={`w-2 h-2 rounded-full ${prio.color} shrink-0`} />
+                  <button onClick={() => onEditTask(task)}
+                    className="text-xs font-medium text-text-primary truncate hover:text-brand-primary text-left">
+                    {task.title}
+                  </button>
+                </div>
+                <div className="relative flex-1" style={{ height: '44px' }}>
+                  {/* Today line */}
+                  {differenceInDays(today, earliest) >= 0 && (
+                    <div
+                      className="absolute top-0 bottom-0 w-px bg-brand-primary/30 z-10"
+                      style={{ left: `${differenceInDays(today, earliest) * dayWidth + dayWidth / 2}px` }}
+                    />
+                  )}
+                  {/* Bar */}
+                  <div
+                    className={`absolute top-2.5 h-5 rounded-full ${statusColors[task.status] || 'bg-gray-300'} opacity-80 hover:opacity-100 transition-opacity cursor-pointer`}
+                    style={barStyle}
+                    onClick={() => onEditTask(task)}
+                    title={`${task.title}${task.dueDate ? ` — Due ${format(new Date(task.dueDate), 'MMM d')}` : ''}`}
+                  />
+                </div>
+              </div>
+            )
+          })}
+        </div>
+      </div>
+
+      {/* Delete Task Confirmation */}
+      <Modal
+        isOpen={showDeleteConfirm}
+        onClose={() => { setShowDeleteConfirm(false); setTaskToDelete(null) }}
+        title="Delete Task?"
+        isConfirm
+        danger
+        confirmText="Delete Task"
+        onConfirm={confirmDeleteTask}
+      >
+        Are you sure you want to delete this task? This action cannot be undone.
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/pages/Projects.jsx b/client/src/pages/Projects.jsx
new file mode 100644
index 0000000..a119053
--- /dev/null
+++ b/client/src/pages/Projects.jsx
@@ -0,0 +1,202 @@
+import { useState, useEffect, useContext } from 'react'
+import { Plus, Search, FolderKanban } from 'lucide-react'
+import { AppContext } from '../App'
+import { api } from '../utils/api'
+import ProjectCard from '../components/ProjectCard'
+import Modal from '../components/Modal'
+
+const EMPTY_PROJECT = {
+  name: '', description: '', brand_id: '', status: 'active',
+  owner_id: '', due_date: '',
+}
+
+export default function Projects() {
+  const { teamMembers, brands } = useContext(AppContext)
+  const [projects, setProjects] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [showModal, setShowModal] = useState(false)
+  const [formData, setFormData] = useState(EMPTY_PROJECT)
+  const [searchTerm, setSearchTerm] = useState('')
+
+  useEffect(() => { loadProjects() }, [])
+
+  const loadProjects = async () => {
+    try {
+      const res = await api.get('/projects')
+      setProjects(res.data || res || [])
+    } catch (err) {
+      console.error('Failed to load projects:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleCreate = async () => {
+    try {
+      const data = {
+        name: formData.name,
+        description: formData.description,
+        brand_id: formData.brand_id ? Number(formData.brand_id) : null,
+        owner_id: formData.owner_id ? Number(formData.owner_id) : null,
+        status: formData.status,
+        due_date: formData.due_date || null,
+      }
+      await api.post('/projects', data)
+      setShowModal(false)
+      setFormData(EMPTY_PROJECT)
+      loadProjects()
+    } catch (err) {
+      console.error('Create failed:', err)
+    }
+  }
+
+  const filtered = projects.filter(p => {
+    if (searchTerm && !p.name?.toLowerCase().includes(searchTerm.toLowerCase())) return false
+    return true
+  })
+
+  if (loading) {
+    return (
+      <div className="animate-pulse">
+        <div className="h-12 bg-surface-tertiary rounded-xl mb-4"></div>
+        <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-4">
+          {[...Array(6)].map((_, i) => <div key={i} className="h-56 bg-surface-tertiary rounded-xl"></div>)}
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-4 animate-fade-in">
+      {/* Toolbar */}
+      <div className="flex flex-wrap items-center gap-3">
+        <div className="relative flex-1 min-w-[200px] max-w-md">
+          <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-text-tertiary" />
+          <input
+            type="text"
+            placeholder="Search projects..."
+            value={searchTerm}
+            onChange={e => setSearchTerm(e.target.value)}
+            className="w-full pl-10 pr-4 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary bg-white"
+          />
+        </div>
+
+        <button
+          onClick={() => setShowModal(true)}
+          className="flex items-center gap-2 px-4 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm ml-auto"
+        >
+          <Plus className="w-4 h-4" />
+          New Project
+        </button>
+      </div>
+
+      {/* Project grid */}
+      {filtered.length === 0 ? (
+        <div className="py-20 text-center">
+          <FolderKanban className="w-12 h-12 text-text-tertiary mx-auto mb-3" />
+          <p className="text-text-secondary font-medium">No projects yet</p>
+          <p className="text-sm text-text-tertiary mt-1">Create your first project to start organizing work</p>
+        </div>
+      ) : (
+        <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-4 stagger-children">
+          {filtered.map(project => (
+            <ProjectCard key={project._id} project={project} />
+          ))}
+        </div>
+      )}
+
+      {/* Create Modal */}
+      <Modal isOpen={showModal} onClose={() => setShowModal(false)} title="Create New Project" size="md">
+        <div className="space-y-4">
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Name *</label>
+            <input
+              type="text"
+              value={formData.name}
+              onChange={e => setFormData(f => ({ ...f, name: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder="Project name"
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Description</label>
+            <textarea
+              value={formData.description}
+              onChange={e => setFormData(f => ({ ...f, description: e.target.value }))}
+              rows={3}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary resize-none"
+              placeholder="Project description..."
+            />
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Brand</label>
+              <select
+                value={formData.brand_id}
+                onChange={e => setFormData(f => ({ ...f, brand_id: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              >
+                <option value="">Select brand</option>
+                {brands.map(b => <option key={b._id} value={b._id}>{b.icon} {b.name}</option>)}
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Status</label>
+              <select
+                value={formData.status}
+                onChange={e => setFormData(f => ({ ...f, status: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              >
+                <option value="active">Active</option>
+                <option value="paused">Paused</option>
+                <option value="completed">Completed</option>
+                <option value="cancelled">Cancelled</option>
+              </select>
+            </div>
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Owner</label>
+              <select
+                value={formData.owner_id}
+                onChange={e => setFormData(f => ({ ...f, owner_id: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              >
+                <option value="">Unassigned</option>
+                {teamMembers.map(m => <option key={m._id} value={m._id}>{m.name}</option>)}
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">Due Date</label>
+              <input
+                type="date"
+                value={formData.due_date}
+                onChange={e => setFormData(f => ({ ...f, due_date: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              />
+            </div>
+          </div>
+
+          <div className="flex items-center justify-end gap-3 pt-4 border-t border-border">
+            <button
+              onClick={() => setShowModal(false)}
+              className="px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg"
+            >
+              Cancel
+            </button>
+            <button
+              onClick={handleCreate}
+              disabled={!formData.name}
+              className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm"
+            >
+              Create Project
+            </button>
+          </div>
+        </div>
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/pages/Settings.jsx b/client/src/pages/Settings.jsx
new file mode 100644
index 0000000..3db628f
--- /dev/null
+++ b/client/src/pages/Settings.jsx
@@ -0,0 +1,110 @@
+import { useState } from 'react'
+import { Settings as SettingsIcon, Play, CheckCircle, Languages } from 'lucide-react'
+import { api } from '../utils/api'
+import { useLanguage } from '../i18n/LanguageContext'
+
+export default function Settings() {
+  const { t, lang, setLang } = useLanguage()
+  const [restarting, setRestarting] = useState(false)
+  const [success, setSuccess] = useState(false)
+
+  const handleRestartTutorial = async () => {
+    setRestarting(true)
+    setSuccess(false)
+    try {
+      await api.patch('/users/me/tutorial', { completed: false })
+      setSuccess(true)
+      setTimeout(() => {
+        window.location.reload() // Reload to trigger tutorial
+      }, 1500)
+    } catch (err) {
+      console.error('Failed to restart tutorial:', err)
+      alert('Failed to restart tutorial')
+    } finally {
+      setRestarting(false)
+    }
+  }
+
+  return (
+    <div className="space-y-6 animate-fade-in max-w-3xl">
+      {/* Header */}
+      <div>
+        <h1 className="text-2xl font-bold text-text-primary flex items-center gap-3">
+          <SettingsIcon className="w-7 h-7 text-brand-primary" />
+          {t('settings.title')}
+        </h1>
+        <p className="text-sm text-text-tertiary mt-1">{t('settings.preferences')}</p>
+      </div>
+
+      {/* General Settings */}
+      <div className="bg-white rounded-xl border border-border overflow-hidden">
+        <div className="px-6 py-4 border-b border-border">
+          <h2 className="text-lg font-semibold text-text-primary">{t('settings.general')}</h2>
+        </div>
+        <div className="p-6 space-y-4">
+          {/* Language Selector */}
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-2 flex items-center gap-2">
+              <Languages className="w-4 h-4" />
+              {t('settings.language')}
+            </label>
+            <select
+              value={lang}
+              onChange={(e) => setLang(e.target.value)}
+              className="w-full max-w-xs px-4 py-2.5 border border-border rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary bg-white"
+            >
+              <option value="en">{t('settings.english')}</option>
+              <option value="ar">{t('settings.arabic')}</option>
+            </select>
+          </div>
+        </div>
+      </div>
+
+      {/* Tutorial Section */}
+      <div className="bg-white rounded-xl border border-border overflow-hidden">
+        <div className="px-6 py-4 border-b border-border">
+          <h2 className="text-lg font-semibold text-text-primary">{t('settings.onboardingTutorial')}</h2>
+        </div>
+        <div className="p-6 space-y-4">
+          <p className="text-sm text-text-secondary">
+            {t('settings.tutorialDesc')}
+          </p>
+          <button
+            onClick={handleRestartTutorial}
+            disabled={restarting || success}
+            className="flex items-center gap-2 px-4 py-2.5 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm transition-colors"
+          >
+            {success ? (
+              <>
+                <CheckCircle className="w-4 h-4" />
+                {t('settings.tutorialRestarted')}
+              </>
+            ) : (
+              <>
+                <Play className="w-4 h-4" />
+                {restarting ? t('settings.restarting') : t('settings.restartTutorial')}
+              </>
+            )}
+          </button>
+          {success && (
+            <p className="text-xs text-emerald-600 font-medium">
+              {t('settings.reloadingPage')}
+            </p>
+          )}
+        </div>
+      </div>
+
+      {/* More settings can go here in the future */}
+      <div className="bg-white rounded-xl border border-border overflow-hidden opacity-50">
+        <div className="px-6 py-4 border-b border-border">
+          <h2 className="text-lg font-semibold text-text-primary">{t('settings.moreComingSoon')}</h2>
+        </div>
+        <div className="p-6">
+          <p className="text-sm text-text-secondary">
+            {t('settings.additionalSettings')}
+          </p>
+        </div>
+      </div>
+    </div>
+  )
+}
diff --git a/client/src/pages/Tasks.jsx b/client/src/pages/Tasks.jsx
new file mode 100644
index 0000000..d46b89b
--- /dev/null
+++ b/client/src/pages/Tasks.jsx
@@ -0,0 +1,423 @@
+import { useState, useEffect, useContext } from 'react'
+import { Plus, CheckSquare, Edit2, Trash2, Filter } from 'lucide-react'
+import { AppContext } from '../App'
+import { useAuth } from '../contexts/AuthContext'
+import { useLanguage } from '../i18n/LanguageContext'
+import { api } from '../utils/api'
+import TaskCard from '../components/TaskCard'
+import Modal from '../components/Modal'
+
+export default function Tasks() {
+  const { t } = useLanguage()
+  const { currentUser, teamMembers } = useContext(AppContext)
+  const { user: authUser, canEditResource, canDeleteResource } = useAuth()
+  const [tasks, setTasks] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [showModal, setShowModal] = useState(false)
+  const [editingTask, setEditingTask] = useState(null)
+  const [draggedTask, setDraggedTask] = useState(null)
+  const [dragOverCol, setDragOverCol] = useState(null)
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+  const [taskToDelete, setTaskToDelete] = useState(null)
+  const [filterView, setFilterView] = useState('all') // 'all' | 'assigned_to_me' | 'created_by_me' | member id
+  const [users, setUsers] = useState([]) // for superadmin member filter
+  const [formData, setFormData] = useState({
+    title: '', description: '', priority: 'medium', due_date: '', status: 'todo', assigned_to: ''
+  })
+
+  const isSuperadmin = authUser?.role === 'superadmin'
+
+  useEffect(() => { loadTasks() }, [currentUser])
+  useEffect(() => {
+    if (isSuperadmin) {
+      // Load team members for superadmin filter
+      api.get('/team').then(res => setUsers(res.data || res || [])).catch(() => {})
+    }
+  }, [isSuperadmin])
+
+  const loadTasks = async () => {
+    try {
+      const res = await api.get('/tasks')
+      setTasks(res.data || res || [])
+    } catch (err) {
+      console.error('Failed to load tasks:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  // Filter tasks client-side based on selected view
+  const filteredTasks = tasks.filter(task => {
+    if (filterView === 'all') return true
+
+    if (filterView === 'assigned_to_me') {
+      // Tasks where I'm the assignee (via team_member_id on my user record)
+      const myTeamMemberId = authUser?.team_member_id
+      return myTeamMemberId && task.assigned_to === myTeamMemberId
+    }
+
+    if (filterView === 'created_by_me') {
+      return task.created_by_user_id === authUser?.id
+    }
+
+    // Superadmin filtering by specific team member (assigned_to = member id)
+    if (isSuperadmin && !isNaN(Number(filterView))) {
+      return task.assigned_to === Number(filterView)
+    }
+
+    return true
+  })
+
+  const handleSave = async () => {
+    try {
+      const data = {
+        title: formData.title,
+        description: formData.description,
+        priority: formData.priority,
+        due_date: formData.due_date || null,
+        status: formData.status,
+        assigned_to: formData.assigned_to || null,
+        is_personal: false,
+      }
+      if (editingTask) {
+        await api.patch(`/tasks/${editingTask._id || editingTask.id}`, data)
+      } else {
+        await api.post('/tasks', data)
+      }
+      setShowModal(false)
+      setEditingTask(null)
+      setFormData({ title: '', description: '', priority: 'medium', due_date: '', status: 'todo', assigned_to: '' })
+      loadTasks()
+    } catch (err) {
+      console.error('Save failed:', err)
+      if (err.message?.includes('403') || err.message?.includes('modify your own')) {
+        alert('You can only edit your own tasks')
+      }
+    }
+  }
+
+  const handleMove = async (taskId, newStatus) => {
+    try {
+      await api.patch(`/tasks/${taskId}`, { status: newStatus })
+      loadTasks()
+    } catch (err) {
+      console.error('Move failed:', err)
+      if (err.message?.includes('403')) {
+        alert('You can only modify your own tasks')
+      }
+    }
+  }
+
+  const openEdit = (task) => {
+    if (!canEditResource('task', task)) return
+    setEditingTask(task)
+    setFormData({
+      title: task.title || '',
+      description: task.description || '',
+      priority: task.priority || 'medium',
+      due_date: task.due_date || task.dueDate || '',
+      status: task.status || 'todo',
+      assigned_to: task.assigned_to || '',
+    })
+    setShowModal(true)
+  }
+
+  const handleDelete = (task) => {
+    if (!canDeleteResource('task', task)) return
+    setTaskToDelete(task)
+    setShowDeleteConfirm(true)
+  }
+
+  const confirmDelete = async () => {
+    if (!taskToDelete) return
+    try {
+      await api.delete(`/tasks/${taskToDelete._id || taskToDelete.id}`)
+      setTaskToDelete(null)
+      loadTasks()
+    } catch (err) {
+      console.error('Delete failed:', err)
+    }
+  }
+
+  const handleDragStart = (e, task) => {
+    setDraggedTask(task)
+    e.dataTransfer.effectAllowed = 'move'
+    if (e.target) {
+      setTimeout(() => e.target.style.opacity = '0.4', 0)
+    }
+  }
+
+  const handleDragEnd = (e) => {
+    e.target.style.opacity = '1'
+    setDraggedTask(null)
+    setDragOverCol(null)
+  }
+
+  const handleDragOver = (e, colStatus) => {
+    e.preventDefault()
+    e.dataTransfer.dropEffect = 'move'
+    setDragOverCol(colStatus)
+  }
+
+  const handleDragLeave = (e) => {
+    if (!e.currentTarget.contains(e.relatedTarget)) {
+      setDragOverCol(null)
+    }
+  }
+
+  const handleDrop = (e, colStatus) => {
+    e.preventDefault()
+    setDragOverCol(null)
+    if (draggedTask && draggedTask.status !== colStatus) {
+      const taskId = draggedTask._id || draggedTask.id
+      handleMove(taskId, colStatus)
+    }
+    setDraggedTask(null)
+  }
+
+  const todoTasks = filteredTasks.filter(t => t.status === 'todo')
+  const inProgressTasks = filteredTasks.filter(t => t.status === 'in_progress')
+  const doneTasks = filteredTasks.filter(t => t.status === 'done')
+
+  if (loading) {
+    return (
+      <div className="animate-pulse">
+        <div className="h-12 bg-surface-tertiary rounded-xl mb-4"></div>
+        <div className="grid grid-cols-3 gap-4">
+          {[...Array(3)].map((_, i) => <div key={i} className="h-64 bg-surface-tertiary rounded-xl"></div>)}
+        </div>
+      </div>
+    )
+  }
+
+  const columns = [
+    { label: t('tasks.todo'), status: 'todo', items: todoTasks, color: 'bg-gray-400' },
+    { label: t('tasks.in_progress'), status: 'in_progress', items: inProgressTasks, color: 'bg-blue-400' },
+    { label: t('tasks.done'), status: 'done', items: doneTasks, color: 'bg-emerald-400' },
+  ]
+
+  return (
+    <div className="space-y-4 animate-fade-in">
+      {/* Toolbar */}
+      <div className="flex items-center justify-between gap-4 flex-wrap">
+        <div className="flex items-center gap-3">
+          <div className="flex items-center gap-2">
+            <Filter className="w-4 h-4 text-text-tertiary" />
+            <select
+              value={filterView}
+              onChange={e => setFilterView(e.target.value)}
+              className="px-3 py-1.5 text-sm border border-border rounded-lg bg-surface-primary text-text-primary focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+            >
+              <option value="all">{t('tasks.allTasks')}</option>
+              <option value="assigned_to_me">{t('tasks.assignedToMe')}</option>
+              <option value="created_by_me">{t('tasks.createdByMe')}</option>
+              {isSuperadmin && users.length > 0 && (
+                <optgroup label={t('tasks.byTeamMember')}>
+                  {users.map(m => (
+                    <option key={m.id} value={m.id}>{m.name}</option>
+                  ))}
+                </optgroup>
+              )}
+            </select>
+          </div>
+          <p className="text-sm text-text-secondary">
+            {filteredTasks.length} {filteredTasks.length !== 1 ? t('tasks.tasks') : t('tasks.task')}
+            {filterView !== 'all' && tasks.length !== filteredTasks.length && (
+              <span className="text-text-tertiary"> {t('tasks.of')} {tasks.length}</span>
+            )}
+          </p>
+        </div>
+        <button
+          onClick={() => { setEditingTask(null); setFormData({ title: '', description: '', priority: 'medium', due_date: '', status: 'todo', assigned_to: '' }); setShowModal(true) }}
+          className="flex items-center gap-2 px-4 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm"
+        >
+          <Plus className="w-4 h-4" />
+          {t('tasks.newTask')}
+        </button>
+      </div>
+
+      {/* Task columns */}
+      {filteredTasks.length === 0 ? (
+        <div className="py-20 text-center">
+          <CheckSquare className="w-12 h-12 text-text-tertiary mx-auto mb-3" />
+          <p className="text-text-secondary font-medium">
+            {tasks.length === 0 ? t('tasks.noTasks') : t('tasks.noMatch')}
+          </p>
+          <p className="text-sm text-text-tertiary mt-1">
+            {tasks.length === 0 ? t('tasks.createFirst') : t('tasks.tryFilter')}
+          </p>
+        </div>
+      ) : (
+        <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
+          {columns.map(col => {
+            const isOver = dragOverCol === col.status && draggedTask?.status !== col.status
+
+            return (
+              <div key={col.status}>
+                <div className="flex items-center gap-2 mb-3">
+                  <div className={`w-2.5 h-2.5 rounded-full ${col.color}`} />
+                  <h4 className="text-sm font-semibold text-text-primary">{col.label}</h4>
+                  <span className="text-xs font-medium text-text-tertiary bg-surface-tertiary px-2 py-0.5 rounded-full">
+                    {col.items.length}
+                  </span>
+                </div>
+                <div
+                  className={`kanban-column rounded-xl p-2 space-y-2 min-h-[200px] border-2 transition-colors ${
+                    isOver
+                      ? 'bg-brand-primary/5 border-brand-primary/40 border-dashed'
+                      : 'bg-surface-secondary border-border-light border-solid'
+                  }`}
+                  onDragOver={(e) => handleDragOver(e, col.status)}
+                  onDragLeave={handleDragLeave}
+                  onDrop={(e) => handleDrop(e, col.status)}
+                >
+                  {col.items.length === 0 ? (
+                    <div className={`py-8 text-center text-xs ${isOver ? 'text-brand-primary font-medium' : 'text-text-tertiary'}`}>
+                      {isOver ? t('posts.dropHere') : t('tasks.noTasks')}
+                    </div>
+                  ) : (
+                    col.items.map(task => {
+                      const canEdit = canEditResource('task', task)
+                      const canDelete = canDeleteResource('task', task)
+                      return (
+                        <div
+                          key={task._id || task.id}
+                          draggable={canEdit}
+                          onDragStart={(e) => canEdit && handleDragStart(e, task)}
+                          onDragEnd={handleDragEnd}
+                          className={canEdit ? 'cursor-grab active:cursor-grabbing' : ''}
+                        >
+                          <div className="relative group">
+                            <TaskCard task={task} onMove={canEdit ? handleMove : undefined} showProject />
+                            {/* Edit/Delete overlay */}
+                            {(canEdit || canDelete) && (
+                              <div className="absolute top-2 right-2 flex items-center gap-0.5 opacity-0 group-hover:opacity-100 transition-opacity">
+                                {canEdit && (
+                                  <button
+                                    onClick={(e) => { e.stopPropagation(); openEdit(task) }}
+                                    className="p-1 hover:bg-surface-tertiary rounded text-text-tertiary hover:text-text-primary"
+                                    title={t('tasks.editTask')}
+                                  >
+                                    <Edit2 className="w-3.5 h-3.5" />
+                                  </button>
+                                )}
+                                {canDelete && (
+                                  <button
+                                    onClick={(e) => { e.stopPropagation(); handleDelete(task) }}
+                                    className="p-1 hover:bg-red-50 rounded text-text-tertiary hover:text-red-500"
+                                    title={t('common.delete')}
+                                  >
+                                    <Trash2 className="w-3.5 h-3.5" />
+                                  </button>
+                                )}
+                              </div>
+                            )}
+                          </div>
+                        </div>
+                      )
+                    })
+                  )}
+                </div>
+              </div>
+            )
+          })}
+        </div>
+      )}
+
+      {/* Create/Edit Task Modal */}
+      <Modal isOpen={showModal} onClose={() => { setShowModal(false); setEditingTask(null) }} title={editingTask ? t('tasks.editTask') : t('tasks.createTask')} size="md">
+        <div className="space-y-4">
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">{t('tasks.taskTitle')} *</label>
+            <input
+              type="text"
+              value={formData.title}
+              onChange={e => setFormData(f => ({ ...f, title: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder={t('posts.whatNeedsDone')}
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">{t('tasks.description')}</label>
+            <textarea
+              value={formData.description}
+              onChange={e => setFormData(f => ({ ...f, description: e.target.value }))}
+              rows={2}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary resize-none"
+              placeholder={t('posts.optionalDetails')}
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">{t('tasks.assignTo')}</label>
+            <select
+              value={formData.assigned_to}
+              onChange={e => setFormData(f => ({ ...f, assigned_to: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+            >
+              <option value="">{t('common.unassigned')}</option>
+              {(teamMembers || []).map(m => (
+                <option key={m.id || m._id} value={m.id || m._id}>{m.name}</option>
+              ))}
+            </select>
+          </div>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('tasks.priority')}</label>
+              <select
+                value={formData.priority}
+                onChange={e => setFormData(f => ({ ...f, priority: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              >
+                <option value="low">{t('tasks.priority.low')}</option>
+                <option value="medium">{t('tasks.priority.medium')}</option>
+                <option value="high">{t('tasks.priority.high')}</option>
+                <option value="urgent">{t('tasks.priority.urgent')}</option>
+              </select>
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('tasks.dueDate')}</label>
+              <input
+                type="date"
+                value={formData.due_date}
+                onChange={e => setFormData(f => ({ ...f, due_date: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              />
+            </div>
+          </div>
+
+          <div className="flex items-center justify-end gap-3 pt-4 border-t border-border">
+            <button
+              onClick={() => { setShowModal(false); setEditingTask(null) }}
+              className="px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg"
+            >
+              {t('common.cancel')}
+            </button>
+            <button
+              onClick={handleSave}
+              disabled={!formData.title}
+              className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm"
+            >
+              {editingTask ? t('tasks.saveChanges') : t('tasks.createTask')}
+            </button>
+          </div>
+        </div>
+      </Modal>
+
+      {/* Delete Confirmation */}
+      <Modal
+        isOpen={showDeleteConfirm}
+        onClose={() => { setShowDeleteConfirm(false); setTaskToDelete(null) }}
+        title={t('tasks.deleteTask')}
+        isConfirm
+        danger
+        confirmText={t('tasks.deleteTask')}
+        onConfirm={confirmDelete}
+      >
+        {t('tasks.deleteConfirm')}
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/pages/Team.jsx b/client/src/pages/Team.jsx
new file mode 100644
index 0000000..9798129
--- /dev/null
+++ b/client/src/pages/Team.jsx
@@ -0,0 +1,448 @@
+import { useState, useEffect, useContext } from 'react'
+import { Plus, Users, ArrowLeft, User as UserIcon } from 'lucide-react'
+import { AppContext } from '../App'
+import { useAuth } from '../contexts/AuthContext'
+import { useLanguage } from '../i18n/LanguageContext'
+import { api } from '../utils/api'
+import MemberCard from '../components/MemberCard'
+import StatusBadge from '../components/StatusBadge'
+import BrandBadge from '../components/BrandBadge'
+import Modal from '../components/Modal'
+
+const EMPTY_MEMBER = {
+  name: '', email: '', password: '', role: 'content_writer', brands: '', phone: '',
+}
+
+const ROLES = [
+  { value: 'manager', label: 'Manager' },
+  { value: 'approver', label: 'Approver' },
+  { value: 'publisher', label: 'Publisher' },
+  { value: 'content_creator', label: 'Content Creator' },
+  { value: 'producer', label: 'Producer' },
+  { value: 'designer', label: 'Designer' },
+  { value: 'content_writer', label: 'Content Writer' },
+  { value: 'social_media_manager', label: 'Social Media Manager' },
+  { value: 'photographer', label: 'Photographer' },
+  { value: 'videographer', label: 'Videographer' },
+  { value: 'strategist', label: 'Strategist' },
+]
+
+export default function Team() {
+  const { t } = useLanguage()
+  const { teamMembers, loadTeam, currentUser } = useContext(AppContext)
+  const { user } = useAuth()
+  const [showModal, setShowModal] = useState(false)
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+  const [editingMember, setEditingMember] = useState(null)
+  const [isEditingSelf, setIsEditingSelf] = useState(false)
+  const [formData, setFormData] = useState(EMPTY_MEMBER)
+  const [selectedMember, setSelectedMember] = useState(null)
+  const [memberTasks, setMemberTasks] = useState([])
+  const [memberPosts, setMemberPosts] = useState([])
+  const [loadingDetail, setLoadingDetail] = useState(false)
+
+  const canManageTeam = user?.role === 'superadmin' || user?.role === 'manager'
+
+  const openNew = () => {
+    setEditingMember(null)
+    setIsEditingSelf(false)
+    setFormData(EMPTY_MEMBER)
+    setShowModal(true)
+  }
+
+  const openEdit = (member) => {
+    const isSelf = member._id === user?.id || member.id === user?.id
+    setEditingMember(member)
+    setIsEditingSelf(isSelf)
+    setFormData({
+      name: member.name || '',
+      email: member.email || '',
+      password: '',
+      role: member.team_role || member.role || 'content_writer',
+      brands: Array.isArray(member.brands) ? member.brands.join(', ') : (member.brands || ''),
+      phone: member.phone || '',
+    })
+    setShowModal(true)
+  }
+
+  const handleSave = async () => {
+    try {
+      const brands = typeof formData.brands === 'string'
+        ? formData.brands.split(',').map(b => b.trim()).filter(Boolean)
+        : formData.brands
+
+      // If editing self, use self-service endpoint
+      if (isEditingSelf) {
+        const data = {
+          name: formData.name,
+          team_role: formData.role,
+          brands,
+          phone: formData.phone,
+        }
+        await api.patch('/users/me/profile', data)
+      } else {
+        // Manager/superadmin creating or editing other users
+        const data = {
+          name: formData.name,
+          email: formData.email,
+          team_role: formData.role,
+          brands,
+          phone: formData.phone,
+        }
+        if (formData.password) {
+          data.password = formData.password
+        }
+        
+        if (editingMember) {
+          await api.patch(`/users/team/${editingMember._id}`, data)
+        } else {
+          await api.post('/users/team', data)
+        }
+      }
+      
+      setShowModal(false)
+      setEditingMember(null)
+      setIsEditingSelf(false)
+      setFormData(EMPTY_MEMBER)
+      loadTeam()
+    } catch (err) {
+      console.error('Save failed:', err)
+      alert(err.message || 'Failed to save')
+    }
+  }
+
+  const openMemberDetail = async (member) => {
+    setSelectedMember(member)
+    setLoadingDetail(true)
+    try {
+      const [tasksRes, postsRes] = await Promise.allSettled([
+        api.get(`/tasks?assignedTo=${member._id}`),
+        api.get(`/posts?assignedTo=${member._id}`),
+      ])
+      setMemberTasks(tasksRes.status === 'fulfilled' ? (tasksRes.value.data || tasksRes.value || []) : [])
+      setMemberPosts(postsRes.status === 'fulfilled' ? (postsRes.value.data || postsRes.value || []) : [])
+    } catch {
+      setMemberTasks([])
+      setMemberPosts([])
+    } finally {
+      setLoadingDetail(false)
+    }
+  }
+
+  // Member detail view
+  if (selectedMember) {
+    const todoCount = memberTasks.filter(t => t.status === 'todo').length
+    const inProgressCount = memberTasks.filter(t => t.status === 'in_progress').length
+    const doneCount = memberTasks.filter(t => t.status === 'done').length
+
+    return (
+      <div className="space-y-6 animate-fade-in">
+        <button
+          onClick={() => setSelectedMember(null)}
+          className="flex items-center gap-2 text-sm text-text-secondary hover:text-text-primary transition-colors"
+        >
+          <ArrowLeft className="w-4 h-4" />
+          {t('team.backToTeam')}
+        </button>
+
+        {/* Member profile */}
+        <div className="bg-white rounded-xl border border-border p-6">
+          <div className="flex items-start gap-4">
+            <div className={`w-16 h-16 rounded-full bg-gradient-to-br from-indigo-400 to-purple-500 flex items-center justify-center text-white text-xl font-bold`}>
+              {selectedMember.name?.split(' ').map(w => w[0]).join('').slice(0, 2).toUpperCase()}
+            </div>
+            <div className="flex-1">
+              <h2 className="text-xl font-bold text-text-primary">{selectedMember.name}</h2>
+              <p className="text-sm text-text-secondary capitalize">{(selectedMember.team_role || selectedMember.role)?.replace('_', ' ')}</p>
+              {selectedMember.email && (
+                <p className="text-sm text-text-tertiary mt-1">{selectedMember.email}</p>
+              )}
+              {selectedMember.brands && selectedMember.brands.length > 0 && (
+                <div className="flex flex-wrap gap-2 mt-3">
+                  {selectedMember.brands.map(b => <BrandBadge key={b} brand={b} />)}
+                </div>
+              )}
+            </div>
+            <button
+              onClick={() => openEdit(selectedMember)}
+              className="px-3 py-1.5 text-sm font-medium text-brand-primary hover:bg-brand-primary/10 rounded-lg"
+            >
+              {t('common.edit')}
+            </button>
+          </div>
+        </div>
+
+        {/* Workload stats */}
+        <div className="grid grid-cols-4 gap-4">
+          <div className="bg-white rounded-xl border border-border p-4 text-center">
+            <p className="text-2xl font-bold text-text-primary">{memberTasks.length}</p>
+            <p className="text-xs text-text-tertiary">{t('team.totalTasks')}</p>
+          </div>
+          <div className="bg-white rounded-xl border border-border p-4 text-center">
+            <p className="text-2xl font-bold text-amber-500">{todoCount}</p>
+            <p className="text-xs text-text-tertiary">{t('team.toDo')}</p>
+          </div>
+          <div className="bg-white rounded-xl border border-border p-4 text-center">
+            <p className="text-2xl font-bold text-blue-500">{inProgressCount}</p>
+            <p className="text-xs text-text-tertiary">{t('team.inProgress')}</p>
+          </div>
+          <div className="bg-white rounded-xl border border-border p-4 text-center">
+            <p className="text-2xl font-bold text-emerald-500">{doneCount}</p>
+            <p className="text-xs text-text-tertiary">{t('tasks.done')}</p>
+          </div>
+        </div>
+
+        {/* Tasks & Posts */}
+        <div className="grid grid-cols-1 lg:grid-cols-2 gap-6">
+          {/* Tasks */}
+          <div className="bg-white rounded-xl border border-border">
+            <div className="px-5 py-4 border-b border-border">
+              <h3 className="font-semibold text-text-primary">{t('tasks.title')} ({memberTasks.length})</h3>
+            </div>
+            <div className="divide-y divide-border-light max-h-[400px] overflow-y-auto">
+              {loadingDetail ? (
+                <div className="py-8 text-center text-sm text-text-tertiary">{t('common.loading')}</div>
+              ) : memberTasks.length === 0 ? (
+                <div className="py-8 text-center text-sm text-text-tertiary">{t('team.noTasks')}</div>
+              ) : (
+                memberTasks.map(task => (
+                  <div key={task._id} className="flex items-center gap-3 px-5 py-3">
+                    <div className="flex-1 min-w-0">
+                      <p className={`text-sm font-medium ${task.status === 'done' ? 'text-text-tertiary line-through' : 'text-text-primary'}`}>
+                        {task.title}
+                      </p>
+                    </div>
+                    <StatusBadge status={task.status} size="xs" />
+                  </div>
+                ))
+              )}
+            </div>
+          </div>
+
+          {/* Posts */}
+          <div className="bg-white rounded-xl border border-border">
+            <div className="px-5 py-4 border-b border-border">
+              <h3 className="font-semibold text-text-primary">{t('nav.posts')} ({memberPosts.length})</h3>
+            </div>
+            <div className="divide-y divide-border-light max-h-[400px] overflow-y-auto">
+              {loadingDetail ? (
+                <div className="py-8 text-center text-sm text-text-tertiary">{t('common.loading')}</div>
+              ) : memberPosts.length === 0 ? (
+                <div className="py-8 text-center text-sm text-text-tertiary">{t('posts.noPosts')}</div>
+              ) : (
+                memberPosts.map(post => (
+                  <div key={post._id} className="flex items-center gap-3 px-5 py-3">
+                    <div className="flex-1 min-w-0">
+                      <p className="text-sm font-medium text-text-primary truncate">{post.title}</p>
+                      {post.brand && <BrandBadge brand={post.brand} />}
+                    </div>
+                    <StatusBadge status={post.status} size="xs" />
+                  </div>
+                ))
+              )}
+            </div>
+          </div>
+        </div>
+      </div>
+    )
+  }
+
+  // Team grid
+  return (
+    <div className="space-y-4 animate-fade-in">
+      {/* Toolbar */}
+      <div className="flex items-center justify-between">
+        <p className="text-sm text-text-secondary">
+          {teamMembers.length} {teamMembers.length !== 1 ? t('team.membersPlural') : t('team.member')}
+        </p>
+        <div className="flex gap-2">
+          {/* Edit own profile button */}
+          <button
+            onClick={() => {
+              const self = teamMembers.find(m => m._id === user?.id || m.id === user?.id)
+              if (self) openEdit(self)
+            }}
+            className="flex items-center gap-2 px-4 py-2 bg-white border border-border text-text-primary rounded-lg text-sm font-medium hover:bg-surface-secondary transition-colors"
+          >
+            <UserIcon className="w-4 h-4" />
+            {t('team.myProfile')}
+          </button>
+          
+          {/* Add member button (managers and superadmins only) */}
+          {canManageTeam && (
+            <button
+              onClick={openNew}
+              className="flex items-center gap-2 px-4 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm"
+            >
+              <Plus className="w-4 h-4" />
+              {t('team.addMember')}
+            </button>
+          )}
+        </div>
+      </div>
+
+      {/* Member grid */}
+      {teamMembers.length === 0 ? (
+        <div className="py-20 text-center">
+          <Users className="w-12 h-12 text-text-tertiary mx-auto mb-3" />
+          <p className="text-text-secondary font-medium">{t('team.noMembers')}</p>
+        </div>
+      ) : (
+        <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-4 stagger-children">
+          {teamMembers.map(member => (
+            <MemberCard key={member._id} member={member} onClick={openMemberDetail} />
+          ))}
+        </div>
+      )}
+
+      {/* Create/Edit Modal */}
+      <Modal
+        isOpen={showModal}
+        onClose={() => { setShowModal(false); setEditingMember(null); setIsEditingSelf(false) }}
+        title={isEditingSelf ? t('team.editProfile') : (editingMember ? t('team.editMember') : t('team.newMember'))}
+        size="md"
+      >
+        <div className="space-y-4">
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">{t('team.name')} *</label>
+            <input
+              type="text"
+              value={formData.name}
+              onChange={e => setFormData(f => ({ ...f, name: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder={t('team.fullName')}
+            />
+          </div>
+
+          {!isEditingSelf && (
+            <>
+              <div>
+                <label className="block text-sm font-medium text-text-primary mb-1">{t('team.email')} *</label>
+                <input
+                  type="email"
+                  value={formData.email}
+                  onChange={e => setFormData(f => ({ ...f, email: e.target.value }))}
+                  className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                  placeholder="email@example.com"
+                  disabled={editingMember}
+                />
+              </div>
+
+              {!editingMember && (
+                <div>
+                  <label className="block text-sm font-medium text-text-primary mb-1">{t('team.password')} {editingMember && t('team.optional')}</label>
+                  <input
+                    type="password"
+                    value={formData.password}
+                    onChange={e => setFormData(f => ({ ...f, password: e.target.value }))}
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                    placeholder="••••••••"
+                  />
+                  {!formData.password && !editingMember && (
+                    <p className="text-xs text-text-tertiary mt-1">{t('team.defaultPassword')}</p>
+                  )}
+                </div>
+              )}
+            </>
+          )}
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('team.teamRole')}</label>
+              {user?.role === 'manager' && !editingMember && !isEditingSelf ? (
+                <>
+                  <input
+                    type="text"
+                    value="Contributor"
+                    disabled
+                    className="w-full px-3 py-2 text-sm border border-border rounded-lg bg-surface-tertiary text-text-tertiary cursor-not-allowed"
+                  />
+                  <p className="text-xs text-text-tertiary mt-1">{t('team.fixedRole')}</p>
+                </>
+              ) : (
+                <select
+                  value={formData.role}
+                  onChange={e => setFormData(f => ({ ...f, role: e.target.value }))}
+                  className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                >
+                  {ROLES.map(r => <option key={r.value} value={r.value}>{r.label}</option>)}
+                </select>
+              )}
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-text-primary mb-1">{t('team.phone')}</label>
+              <input
+                type="text"
+                value={formData.phone}
+                onChange={e => setFormData(f => ({ ...f, phone: e.target.value }))}
+                className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+                placeholder="+966 ..."
+              />
+            </div>
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">{t('team.brands')}</label>
+            <input
+              type="text"
+              value={formData.brands}
+              onChange={e => setFormData(f => ({ ...f, brands: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder="Samaya Investment, Hira Cultural District"
+            />
+            <p className="text-xs text-text-tertiary mt-1">{t('team.brandsHelp')}</p>
+          </div>
+
+          <div className="flex items-center justify-end gap-3 pt-4 border-t border-border">
+            {editingMember && !isEditingSelf && canManageTeam && (
+              <button
+                onClick={() => setShowDeleteConfirm(true)}
+                className="px-4 py-2 text-sm font-medium text-red-600 hover:bg-red-50 rounded-lg mr-auto"
+              >
+                {t('team.remove')}
+              </button>
+            )}
+            <button
+              onClick={() => { setShowModal(false); setEditingMember(null); setIsEditingSelf(false) }}
+              className="px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg"
+            >
+              {t('common.cancel')}
+            </button>
+            <button
+              onClick={handleSave}
+              disabled={!formData.name || (!isEditingSelf && !editingMember && !formData.email)}
+              className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm"
+            >
+              {isEditingSelf ? t('team.saveProfile') : (editingMember ? t('team.saveChanges') : t('team.addMember'))}
+            </button>
+          </div>
+        </div>
+      </Modal>
+
+      {/* Delete Confirmation */}
+      <Modal
+        isOpen={showDeleteConfirm}
+        onClose={() => setShowDeleteConfirm(false)}
+        title={t('team.removeMember')}
+        isConfirm
+        danger
+        confirmText={t('team.remove')}
+        onConfirm={async () => {
+          if (editingMember) {
+            await api.delete(`/users/team/${editingMember._id}`)
+            setShowModal(false)
+            setEditingMember(null)
+            setIsEditingSelf(false)
+            setShowDeleteConfirm(false)
+            if (selectedMember?._id === editingMember._id) {
+              setSelectedMember(null)
+            }
+            loadTeam()
+          }
+        }}
+      >
+        {t('team.removeConfirm', { name: editingMember?.name })}
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/pages/Users.jsx b/client/src/pages/Users.jsx
new file mode 100644
index 0000000..0ae9299
--- /dev/null
+++ b/client/src/pages/Users.jsx
@@ -0,0 +1,315 @@
+import { useState, useEffect } from 'react'
+import { Plus, Shield, Edit2, Trash2, UserCheck } from 'lucide-react'
+import { api } from '../utils/api'
+import Modal from '../components/Modal'
+import { useAuth } from '../contexts/AuthContext'
+
+const ROLES = [
+  { value: 'superadmin', label: 'Superadmin', color: 'bg-purple-100 text-purple-700', icon: '👑' },
+  { value: 'manager', label: 'Manager', color: 'bg-blue-100 text-blue-700', icon: '📊' },
+  { value: 'contributor', label: 'Contributor', color: 'bg-green-100 text-green-700', icon: '✏️' },
+]
+
+const EMPTY_FORM = {
+  name: '', email: '', password: '', role: 'contributor', avatar: '',
+}
+
+function RoleBadge({ role }) {
+  const roleInfo = ROLES.find(r => r.value === role) || ROLES[2]
+  return (
+    <span className={`inline-flex items-center gap-1 text-xs font-medium px-2.5 py-1 rounded-full ${roleInfo.color}`}>
+      <span>{roleInfo.icon}</span>
+      {roleInfo.label}
+    </span>
+  )
+}
+
+export default function Users() {
+  const { user: currentUser } = useAuth()
+  const [users, setUsers] = useState([])
+  const [loading, setLoading] = useState(true)
+  const [showModal, setShowModal] = useState(false)
+  const [editingUser, setEditingUser] = useState(null)
+  const [form, setForm] = useState(EMPTY_FORM)
+  const [showDeleteConfirm, setShowDeleteConfirm] = useState(false)
+  const [userToDelete, setUserToDelete] = useState(null)
+
+  useEffect(() => { loadUsers() }, [])
+
+  const loadUsers = async () => {
+    try {
+      const res = await api.get('/users')
+      setUsers(res)
+    } catch (err) {
+      console.error('Failed to load users:', err)
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const handleSave = async () => {
+    try {
+      const data = {
+        name: form.name,
+        email: form.email,
+        role: form.role,
+        avatar: form.avatar || null,
+      }
+      if (form.password) data.password = form.password
+
+      if (editingUser) {
+        await api.patch(`/users/${editingUser.id}`, data)
+      } else {
+        if (!form.password) {
+          alert('Password is required for new users')
+          return
+        }
+        data.password = form.password
+        await api.post('/users', data)
+      }
+      setShowModal(false)
+      setEditingUser(null)
+      setForm(EMPTY_FORM)
+      loadUsers()
+    } catch (err) {
+      console.error('Save failed:', err)
+      alert('Failed to save user: ' + err.message)
+    }
+  }
+
+  const openEdit = (user) => {
+    setEditingUser(user)
+    setForm({
+      name: user.name || '',
+      email: user.email || '',
+      password: '',
+      role: user.role || 'contributor',
+      avatar: user.avatar || '',
+    })
+    setShowModal(true)
+  }
+
+  const openNew = () => {
+    setEditingUser(null)
+    setForm(EMPTY_FORM)
+    setShowModal(true)
+  }
+
+  const confirmDelete = async () => {
+    if (!userToDelete) return
+    try {
+      await api.delete(`/users/${userToDelete.id}`)
+      loadUsers()
+      setUserToDelete(null)
+    } catch (err) {
+      console.error('Delete failed:', err)
+      alert('Failed to delete user')
+    }
+  }
+
+  if (loading) {
+    return (
+      <div className="space-y-4 animate-pulse">
+        <div className="h-12 bg-surface-tertiary rounded-xl"></div>
+        <div className="h-64 bg-surface-tertiary rounded-xl"></div>
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-6 animate-fade-in">
+      {/* Header */}
+      <div className="flex items-center justify-between">
+        <div>
+          <h1 className="text-2xl font-bold text-text-primary flex items-center gap-3">
+            <Shield className="w-7 h-7 text-purple-600" />
+            User Management
+          </h1>
+          <p className="text-sm text-text-tertiary mt-1">{users.length} user{users.length !== 1 ? 's' : ''}</p>
+        </div>
+        <button
+          onClick={openNew}
+          className="flex items-center gap-2 px-4 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light shadow-sm"
+        >
+          <Plus className="w-4 h-4" />
+          Add User
+        </button>
+      </div>
+
+      {/* Users List */}
+      <div className="bg-white rounded-xl border border-border overflow-hidden">
+        <table className="w-full">
+          <thead>
+            <tr className="border-b border-border bg-surface-secondary">
+              <th className="text-left px-5 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">User</th>
+              <th className="text-left px-5 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">Email</th>
+              <th className="text-left px-5 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">Role</th>
+              <th className="text-left px-5 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider">Created</th>
+              <th className="text-right px-5 py-3 text-xs font-semibold text-text-tertiary uppercase tracking-wider w-24">Actions</th>
+            </tr>
+          </thead>
+          <tbody className="divide-y divide-border-light">
+            {users.length === 0 ? (
+              <tr>
+                <td colSpan={5} className="py-12 text-center text-sm text-text-tertiary">
+                  No users found
+                </td>
+              </tr>
+            ) : (
+              users.map(user => {
+                const isCurrentUser = currentUser?.id === user.id
+                const roleInfo = ROLES.find(r => r.value === user.role) || ROLES[2]
+                return (
+                  <tr key={user.id} className="hover:bg-surface-secondary group">
+                    <td className="px-5 py-4">
+                      <div className="flex items-center gap-3">
+                        <div className={`w-10 h-10 rounded-full bg-gradient-to-br ${user.role === 'superadmin' ? 'from-purple-500 to-pink-500' : 'from-blue-500 to-indigo-500'} flex items-center justify-center text-white font-bold text-sm`}>
+                          {user.name?.split(' ').map(w => w[0]).join('').slice(0, 2).toUpperCase()}
+                        </div>
+                        <div>
+                          <div className="flex items-center gap-2">
+                            <p className="text-sm font-medium text-text-primary">{user.name}</p>
+                            {isCurrentUser && (
+                              <span className="text-[10px] px-1.5 py-0.5 rounded bg-emerald-100 text-emerald-700 font-medium">
+                                You
+                              </span>
+                            )}
+                          </div>
+                        </div>
+                      </div>
+                    </td>
+                    <td className="px-5 py-4 text-sm text-text-secondary">{user.email}</td>
+                    <td className="px-5 py-4">
+                      <RoleBadge role={user.role} />
+                    </td>
+                    <td className="px-5 py-4 text-sm text-text-tertiary">
+                      {user.createdAt ? new Date(user.createdAt).toLocaleDateString() : '—'}
+                    </td>
+                    <td className="px-5 py-4">
+                      <div className="flex items-center justify-end gap-1">
+                        <button
+                          onClick={() => openEdit(user)}
+                          className="p-1.5 hover:bg-surface-tertiary rounded-lg text-text-tertiary hover:text-text-primary"
+                          title="Edit user"
+                        >
+                          <Edit2 className="w-4 h-4" />
+                        </button>
+                        {!isCurrentUser && (
+                          <button
+                            onClick={() => { setUserToDelete(user); setShowDeleteConfirm(true) }}
+                            className="p-1.5 hover:bg-red-50 rounded-lg text-text-tertiary hover:text-red-500"
+                            title="Delete user"
+                          >
+                            <Trash2 className="w-4 h-4" />
+                          </button>
+                        )}
+                      </div>
+                    </td>
+                  </tr>
+                )
+              })
+            )}
+          </tbody>
+        </table>
+      </div>
+
+      {/* Add/Edit User Modal */}
+      <Modal
+        isOpen={showModal}
+        onClose={() => { setShowModal(false); setEditingUser(null) }}
+        title={editingUser ? 'Edit User' : 'Add New User'}
+        size="md"
+      >
+        <div className="space-y-4">
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Name *</label>
+            <input
+              type="text"
+              value={form.name}
+              onChange={e => setForm(f => ({ ...f, name: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder="Full name"
+              required
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Email *</label>
+            <input
+              type="email"
+              value={form.email}
+              onChange={e => setForm(f => ({ ...f, email: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder="user@samayainvest.com"
+              required
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">
+              Password {editingUser && '(leave blank to keep current)'}
+            </label>
+            <input
+              type="password"
+              value={form.password}
+              onChange={e => setForm(f => ({ ...f, password: e.target.value }))}
+              className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
+              placeholder="••••••••"
+              required={!editingUser}
+            />
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-text-primary mb-1">Role *</label>
+            <div className="grid grid-cols-3 gap-2">
+              {ROLES.map(r => (
+                <button
+                  key={r.value}
+                  type="button"
+                  onClick={() => setForm(f => ({ ...f, role: r.value }))}
+                  className={`p-3 rounded-lg border-2 text-center transition-all ${
+                    form.role === r.value
+                      ? 'border-brand-primary bg-brand-primary/5'
+                      : 'border-border hover:border-brand-primary/30'
+                  }`}
+                >
+                  <div className="text-2xl mb-1">{r.icon}</div>
+                  <div className="text-xs font-medium text-text-primary">{r.label}</div>
+                </button>
+              ))}
+            </div>
+          </div>
+
+          <div className="flex items-center justify-end gap-3 pt-4 border-t border-border">
+            <button
+              onClick={() => { setShowModal(false); setEditingUser(null) }}
+              className="px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg"
+            >
+              Cancel
+            </button>
+            <button
+              onClick={handleSave}
+              disabled={!form.name || !form.email || (!editingUser && !form.password)}
+              className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm"
+            >
+              {editingUser ? 'Save Changes' : 'Add User'}
+            </button>
+          </div>
+        </div>
+      </Modal>
+
+      {/* Delete Confirmation */}
+      <Modal
+        isOpen={showDeleteConfirm}
+        onClose={() => { setShowDeleteConfirm(false); setUserToDelete(null) }}
+        title="Delete User?"
+        isConfirm
+        danger
+        confirmText="Delete User"
+        onConfirm={confirmDelete}
+      >
+        Are you sure you want to delete <strong>{userToDelete?.name}</strong>? This action cannot be undone.
+      </Modal>
+    </div>
+  )
+}
diff --git a/client/src/utils/api.js b/client/src/utils/api.js
new file mode 100644
index 0000000..3582259
--- /dev/null
+++ b/client/src/utils/api.js
@@ -0,0 +1,125 @@
+const API = '/api';
+
+// Map SQLite fields to frontend-friendly format
+const toCamel = (s) => s.replace(/_([a-z])/g, (_, c) => c.toUpperCase());
+
+const normalize = (data) => {
+  if (Array.isArray(data)) return data.map(normalize);
+  if (data && typeof data === 'object' && !Array.isArray(data)) {
+    const out = {};
+    for (const [k, v] of Object.entries(data)) {
+      const camelKey = toCamel(k);
+      out[camelKey] = v;
+      if (camelKey !== k) out[k] = v;
+    }
+    // Add _id alias
+    if (out.id !== undefined && out._id === undefined) out._id = out.id;
+    // Map brand_name → brand (frontend expects post.brand as string)
+    if (out.brandName && !out.brand) out.brand = out.brandName;
+    // Map assigned_name for display
+    if (out.assignedName && !out.assignedToName) out.assignedToName = out.assignedName;
+    return out;
+  }
+  return data;
+};
+
+const handleResponse = async (r, label) => {
+  if (!r.ok) {
+    if (r.status === 401 || r.status === 403) {
+      // Unauthorized - redirect to login if not already there
+      if (!window.location.pathname.includes('/login')) {
+        window.location.href = '/login';
+      }
+    }
+    throw new Error(`${label} failed: ${r.status}`);
+  }
+  const json = await r.json();
+  return normalize(json);
+};
+
+export const api = {
+  get: (path) => fetch(`${API}${path}`, {
+    credentials: 'include'
+  }).then(r => handleResponse(r, `GET ${path}`)),
+  
+  post: (path, data) => fetch(`${API}${path}`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    credentials: 'include',
+    body: JSON.stringify(data),
+  }).then(r => handleResponse(r, `POST ${path}`)),
+  
+  patch: (path, data) => fetch(`${API}${path}`, {
+    method: 'PATCH',
+    headers: { 'Content-Type': 'application/json' },
+    credentials: 'include',
+    body: JSON.stringify(data),
+  }).then(r => handleResponse(r, `PATCH ${path}`)),
+  
+  delete: (path) => fetch(`${API}${path}`, {
+    method: 'DELETE',
+    credentials: 'include',
+  }).then(r => handleResponse(r, `DELETE ${path}`)),
+  
+  upload: (path, formData) => fetch(`${API}${path}`, {
+    method: 'POST',
+    credentials: 'include',
+    body: formData,
+  }).then(r => handleResponse(r, `UPLOAD ${path}`)),
+};
+
+// Brand colors map — matches Samaya brands from backend
+export const BRAND_COLORS = {
+  'Samaya Investment': { bg: 'bg-indigo-100', text: 'text-indigo-700', dot: 'bg-indigo-500' },
+  'Hira Cultural District': { bg: 'bg-amber-100', text: 'text-amber-700', dot: 'bg-amber-500' },
+  'Holy Quran Museum': { bg: 'bg-emerald-100', text: 'text-emerald-700', dot: 'bg-emerald-500' },
+  'Al-Safiya Museum': { bg: 'bg-purple-100', text: 'text-purple-700', dot: 'bg-purple-500' },
+  'Hayhala': { bg: 'bg-red-100', text: 'text-red-700', dot: 'bg-red-500' },
+  'Jabal Thawr': { bg: 'bg-stone-100', text: 'text-stone-700', dot: 'bg-stone-500' },
+  'Coffee Chain': { bg: 'bg-orange-100', text: 'text-orange-700', dot: 'bg-orange-500' },
+  'Taibah Gifts': { bg: 'bg-pink-100', text: 'text-pink-700', dot: 'bg-pink-500' },
+  'Google Maps': { bg: 'bg-blue-100', text: 'text-blue-700', dot: 'bg-blue-500' },
+  'default': { bg: 'bg-gray-100', text: 'text-gray-700', dot: 'bg-gray-500' },
+};
+
+export const getBrandColor = (brand) => BRAND_COLORS[brand] || BRAND_COLORS['default'];
+
+// Platform icons helper — svg paths for inline icons
+export const PLATFORMS = {
+  instagram: { label: 'Instagram', color: '#E4405F', icon: 'M12 2.163c3.204 0 3.584.012 4.85.07 3.252.148 4.771 1.691 4.919 4.919.058 1.265.069 1.645.069 4.849 0 3.205-.012 3.584-.069 4.849-.149 3.225-1.664 4.771-4.919 4.919-1.266.058-1.644.07-4.85.07-3.204 0-3.584-.012-4.849-.07-3.26-.149-4.771-1.699-4.919-4.92-.058-1.265-.07-1.644-.07-4.849 0-3.204.013-3.583.07-4.849.149-3.227 1.664-4.771 4.919-4.919 1.266-.057 1.645-.069 4.849-.069zM12 0C8.741 0 8.333.014 7.053.072 2.695.272.273 2.69.073 7.052.014 8.333 0 8.741 0 12c0 3.259.014 3.668.072 4.948.2 4.358 2.618 6.78 6.98 6.98C8.333 23.986 8.741 24 12 24c3.259 0 3.668-.014 4.948-.072 4.354-.2 6.782-2.618 6.979-6.98.059-1.28.073-1.689.073-4.948 0-3.259-.014-3.667-.072-4.947-.196-4.354-2.617-6.78-6.979-6.98C15.668.014 15.259 0 12 0zm0 5.838a6.162 6.162 0 100 12.324 6.162 6.162 0 000-12.324zM12 16a4 4 0 110-8 4 4 0 010 8zm6.406-11.845a1.44 1.44 0 100 2.881 1.44 1.44 0 000-2.881z' },
+  twitter: { label: 'X', color: '#000000', icon: 'M18.244 2.25h3.308l-7.227 8.26 8.502 11.24H16.17l-5.214-6.817L4.99 21.75H1.68l7.73-8.835L1.254 2.25H8.08l4.713 6.231zm-1.161 17.52h1.833L7.084 4.126H5.117z' },
+  facebook: { label: 'Facebook', color: '#1877F2', icon: 'M24 12.073c0-6.627-5.373-12-12-12s-12 5.373-12 12c0 5.99 4.388 10.954 10.125 11.854v-8.385H7.078v-3.47h3.047V9.43c0-3.007 1.792-4.669 4.533-4.669 1.312 0 2.686.235 2.686.235v2.953H15.83c-1.491 0-1.956.925-1.956 1.874v2.25h3.328l-.532 3.47h-2.796v8.385C19.612 23.027 24 18.062 24 12.073z' },
+  linkedin: { label: 'LinkedIn', color: '#0A66C2', icon: 'M20.447 20.452h-3.554v-5.569c0-1.328-.027-3.037-1.852-3.037-1.853 0-2.136 1.445-2.136 2.939v5.667H9.351V9h3.414v1.561h.046c.477-.9 1.637-1.85 3.37-1.85 3.601 0 4.267 2.37 4.267 5.455v6.286zM5.337 7.433a2.062 2.062 0 01-2.063-2.065 2.064 2.064 0 112.063 2.065zm1.782 13.019H3.555V9h3.564v11.452zM22.225 0H1.771C.792 0 0 .774 0 1.729v20.542C0 23.227.792 24 1.771 24h20.451C23.2 24 24 23.227 24 22.271V1.729C24 .774 23.2 0 22.222 0h.003z' },
+  tiktok: { label: 'TikTok', color: '#000000', icon: 'M12.525.02c1.31-.02 2.61-.01 3.91-.02.08 1.53.63 3.09 1.75 4.17 1.12 1.11 2.7 1.62 4.24 1.79v4.03c-1.44-.05-2.89-.35-4.2-.97-.57-.26-1.1-.59-1.62-.93-.01 2.92.01 5.84-.02 8.75-.08 1.4-.54 2.79-1.35 3.94-1.31 1.92-3.58 3.17-5.91 3.21-1.43.08-2.86-.31-4.08-1.03-2.02-1.19-3.44-3.37-3.65-5.71-.02-.5-.03-1-.01-1.49.18-1.9 1.12-3.72 2.58-4.96 1.66-1.44 3.98-2.13 6.15-1.72.02 1.48-.04 2.96-.04 4.44-.99-.32-2.15-.23-3.02.37-.63.41-1.11 1.04-1.36 1.75-.21.51-.15 1.07-.14 1.61.24 1.64 1.82 3.02 3.5 2.87 1.12-.01 2.19-.66 2.77-1.61.19-.33.4-.67.41-1.06.1-1.79.06-3.57.07-5.36.01-4.03-.01-8.05.02-12.07z' },
+  youtube: { label: 'YouTube', color: '#FF0000', icon: 'M23.498 6.186a3.016 3.016 0 00-2.122-2.136C19.505 3.545 12 3.545 12 3.545s-7.505 0-9.377.505A3.017 3.017 0 00.502 6.186C0 8.07 0 12 0 12s0 3.93.502 5.814a3.016 3.016 0 002.122 2.136c1.871.505 9.376.505 9.376.505s7.505 0 9.377-.505a3.015 3.015 0 002.122-2.136C24 15.93 24 12 24 12s0-3.93-.502-5.814zM9.545 15.568V8.432L15.818 12l-6.273 3.568z' },
+  snapchat: { label: 'Snapchat', color: '#FFFC00', icon: 'M12.017 0C5.396 0 .029 5.367.029 11.987c0 5.079 3.158 9.417 7.618 11.162-.105-.949-.199-2.403.041-3.439.219-.937 1.406-5.957 1.406-5.957s-.359-.72-.359-1.781c0-1.668.967-2.914 2.171-2.914 1.023 0 1.518.769 1.518 1.69 0 1.029-.655 2.568-.994 3.995-.283 1.194.599 2.169 1.777 2.169 2.133 0 3.772-2.249 3.772-5.495 0-2.873-2.064-4.882-5.012-4.882-3.414 0-5.418 2.561-5.418 5.207 0 1.031.397 2.138.893 2.738a.36.36 0 01.083.345l-.333 1.36c-.053.22-.174.267-.402.161-1.499-.698-2.436-2.889-2.436-4.649 0-3.785 2.75-7.262 7.929-7.262 4.163 0 7.398 2.967 7.398 6.931 0 4.136-2.607 7.464-6.227 7.464-1.216 0-2.359-.631-2.75-1.378l-.748 2.853c-.271 1.043-1.002 2.35-1.492 3.146C9.57 23.812 10.763 24 12.017 24c6.624 0 11.99-5.367 11.99-11.988C24.007 5.367 18.641 0 12.017 0z' },
+  google_ads: { label: 'Google Ads', color: '#4285F4', icon: 'M12 0C5.372 0 0 5.373 0 12s5.372 12 12 12 12-5.373 12-12S18.628 0 12 0zm5.82 16.32l-2.16 1.25c-.37.21-.84.09-1.05-.28l-5.82-10.08c-.21-.37-.09-.84.28-1.05l2.16-1.25c.37-.21.84-.09 1.05.28l5.82 10.08c.21.37.09.84-.28 1.05z' },
+};
+
+// Status config
+export const STATUS_CONFIG = {
+  draft: { label: 'Draft', bg: 'bg-gray-100', text: 'text-gray-600', dot: 'bg-gray-400' },
+  in_review: { label: 'In Review', bg: 'bg-amber-50', text: 'text-amber-700', dot: 'bg-amber-400' },
+  approved: { label: 'Approved', bg: 'bg-blue-50', text: 'text-blue-700', dot: 'bg-blue-400' },
+  scheduled: { label: 'Scheduled', bg: 'bg-purple-50', text: 'text-purple-700', dot: 'bg-purple-400' },
+  published: { label: 'Published', bg: 'bg-emerald-50', text: 'text-emerald-700', dot: 'bg-emerald-400' },
+  rejected: { label: 'Rejected', bg: 'bg-red-50', text: 'text-red-700', dot: 'bg-red-400' },
+  todo: { label: 'To Do', bg: 'bg-gray-100', text: 'text-gray-600', dot: 'bg-gray-400' },
+  in_progress: { label: 'In Progress', bg: 'bg-blue-50', text: 'text-blue-700', dot: 'bg-blue-400' },
+  done: { label: 'Done', bg: 'bg-emerald-50', text: 'text-emerald-700', dot: 'bg-emerald-400' },
+  active: { label: 'Active', bg: 'bg-emerald-50', text: 'text-emerald-700', dot: 'bg-emerald-400' },
+  paused: { label: 'Paused', bg: 'bg-amber-50', text: 'text-amber-700', dot: 'bg-amber-400' },
+  completed: { label: 'Completed', bg: 'bg-blue-50', text: 'text-blue-700', dot: 'bg-blue-400' },
+  cancelled: { label: 'Cancelled', bg: 'bg-red-50', text: 'text-red-700', dot: 'bg-red-400' },
+  planning: { label: 'Planning', bg: 'bg-gray-100', text: 'text-gray-600', dot: 'bg-gray-400' },
+};
+
+export const getStatusConfig = (status) => STATUS_CONFIG[status] || STATUS_CONFIG['draft'];
+
+// Priority config
+export const PRIORITY_CONFIG = {
+  low: { label: 'Low', color: 'bg-gray-400' },
+  medium: { label: 'Medium', color: 'bg-amber-400' },
+  high: { label: 'High', color: 'bg-orange-500' },
+  urgent: { label: 'Urgent', color: 'bg-red-500' },
+};
diff --git a/client/update-inputs.sh b/client/update-inputs.sh
new file mode 100755
index 0000000..338df3d
--- /dev/null
+++ b/client/update-inputs.sh
@@ -0,0 +1,9 @@
+#!/bin/bash
+
+# Script to add dir="auto" to all input and textarea elements
+# This enables automatic RTL/LTR detection for mixed content
+
+find ./src -name "*.jsx" -type f -exec sed -i 's/<input$[^>]*$$type="text"\|type="email"\|type="url"\|type="search"$$[^>]*$>/<input\1\2\3 dir="auto">/g' {} \;
+find ./src -name "*.jsx" -type f -exec sed -i 's/<textarea$[^>]*$>/<textarea\1 dir="auto">/g' {} \;
+
+echo "Updated all text inputs and textareas with dir='auto'"
diff --git a/client/vite.config.js b/client/vite.config.js
new file mode 100644
index 0000000..3ce863d
--- /dev/null
+++ b/client/vite.config.js
@@ -0,0 +1,16 @@
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+import tailwindcss from '@tailwindcss/vite'
+
+export default defineConfig({
+  plugins: [react(), tailwindcss()],
+  server: {
+    port: 5173,
+    proxy: {
+      '/api': {
+        target: 'http://localhost:3001',
+        changeOrigin: true,
+      },
+    },
+  },
+})
diff --git a/server/db.js b/server/db.js
new file mode 100644
index 0000000..5f7d00a
--- /dev/null
+++ b/server/db.js
@@ -0,0 +1,410 @@
+const Database = require('better-sqlite3');
+const path = require('path');
+const bcrypt = require('bcrypt');
+
+const DB_PATH = path.join(__dirname, 'marketing.db');
+
+const db = new Database(DB_PATH);
+
+// Enable WAL mode and foreign keys
+db.pragma('journal_mode = WAL');
+db.pragma('foreign_keys = ON');
+
+function initialize() {
+  // Create tables
+  db.exec(`
+    CREATE TABLE IF NOT EXISTS team_members (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      name TEXT NOT NULL,
+      email TEXT,
+      role TEXT,
+      avatar_url TEXT,
+      brands TEXT DEFAULT '[]',
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+
+    CREATE TABLE IF NOT EXISTS brands (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      name TEXT NOT NULL,
+      priority INTEGER DEFAULT 2,
+      color TEXT,
+      icon TEXT,
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+
+    CREATE TABLE IF NOT EXISTS posts (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      title TEXT NOT NULL,
+      description TEXT,
+      brand_id INTEGER REFERENCES brands(id),
+      assigned_to INTEGER REFERENCES team_members(id),
+      status TEXT DEFAULT 'draft',
+      platform TEXT,
+      content_type TEXT,
+      scheduled_date DATETIME,
+      published_date DATETIME,
+      notes TEXT,
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+      updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+
+    CREATE TABLE IF NOT EXISTS assets (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      filename TEXT NOT NULL,
+      original_name TEXT,
+      mime_type TEXT,
+      size INTEGER,
+      tags TEXT DEFAULT '[]',
+      brand_id INTEGER REFERENCES brands(id),
+      campaign_id INTEGER REFERENCES campaigns(id),
+      uploaded_by INTEGER REFERENCES team_members(id),
+      folder TEXT DEFAULT 'general',
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+
+    CREATE TABLE IF NOT EXISTS campaigns (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      name TEXT NOT NULL,
+      description TEXT,
+      brand_id INTEGER REFERENCES brands(id),
+      start_date DATE NOT NULL,
+      end_date DATE NOT NULL,
+      status TEXT DEFAULT 'planning',
+      color TEXT,
+      budget REAL,
+      goals TEXT,
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+
+    CREATE TABLE IF NOT EXISTS projects (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      name TEXT NOT NULL,
+      description TEXT,
+      brand_id INTEGER REFERENCES brands(id),
+      owner_id INTEGER REFERENCES team_members(id),
+      status TEXT DEFAULT 'active',
+      priority TEXT DEFAULT 'medium',
+      due_date DATE,
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+
+    CREATE TABLE IF NOT EXISTS tasks (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      title TEXT NOT NULL,
+      description TEXT,
+      project_id INTEGER REFERENCES projects(id),
+      assigned_to INTEGER REFERENCES team_members(id),
+      created_by INTEGER REFERENCES team_members(id),
+      status TEXT DEFAULT 'todo',
+      priority TEXT DEFAULT 'medium',
+      due_date DATE,
+      is_personal BOOLEAN DEFAULT 0,
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+      completed_at DATETIME
+    );
+  `);
+
+  // Budget entries table — tracks money received
+  db.exec(`
+    CREATE TABLE IF NOT EXISTS budget_entries (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      label TEXT NOT NULL,
+      amount REAL NOT NULL,
+      source TEXT,
+      campaign_id INTEGER REFERENCES campaigns(id),
+      category TEXT DEFAULT 'marketing',
+      date_received DATE NOT NULL,
+      notes TEXT DEFAULT '',
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+  `);
+
+  // Users table for authentication
+  db.exec(`
+    CREATE TABLE IF NOT EXISTS users (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      name TEXT NOT NULL,
+      email TEXT NOT NULL UNIQUE,
+      password_hash TEXT NOT NULL,
+      role TEXT NOT NULL DEFAULT 'contributor',
+      avatar TEXT,
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+  `);
+
+  // Campaign tracks table
+  db.exec(`
+    CREATE TABLE IF NOT EXISTS campaign_tracks (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      campaign_id INTEGER NOT NULL REFERENCES campaigns(id) ON DELETE CASCADE,
+      name TEXT,
+      type TEXT NOT NULL DEFAULT 'organic_social',
+      platform TEXT,
+      budget_allocated REAL DEFAULT 0,
+      budget_spent REAL DEFAULT 0,
+      revenue REAL DEFAULT 0,
+      impressions INTEGER DEFAULT 0,
+      clicks INTEGER DEFAULT 0,
+      conversions INTEGER DEFAULT 0,
+      notes TEXT DEFAULT '',
+      status TEXT DEFAULT 'planned',
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+  `);
+
+  // ─── Ownership columns (link to users table) ───
+  const addOwnership = (table, column) => {
+    const cols = db.prepare(`PRAGMA table_info(${table})`).all().map(c => c.name);
+    if (!cols.includes(column)) {
+      db.exec(`ALTER TABLE ${table} ADD COLUMN ${column} INTEGER REFERENCES users(id)`);
+      console.log(`✅ Added ${column} column to ${table}`);
+    }
+  };
+  addOwnership('posts', 'created_by_user_id');
+  addOwnership('tasks', 'created_by_user_id');
+  addOwnership('campaigns', 'created_by_user_id');
+  addOwnership('projects', 'created_by_user_id');
+
+  // Add phone column to team_members if missing
+  const teamMemberCols = db.prepare("PRAGMA table_info(team_members)").all().map(c => c.name);
+  if (!teamMemberCols.includes('phone')) {
+    db.exec("ALTER TABLE team_members ADD COLUMN phone TEXT");
+    console.log('✅ Added phone column to team_members');
+  }
+
+  // Migrations — add columns if they don't exist
+  const campaignCols = db.prepare("PRAGMA table_info(campaigns)").all().map(c => c.name);
+  if (!campaignCols.includes('platforms')) {
+    db.exec("ALTER TABLE campaigns ADD COLUMN platforms TEXT DEFAULT '[]'");
+    console.log('✅ Added platforms column to campaigns');
+  }
+
+  // Campaign performance tracking columns
+  if (!campaignCols.includes('budget_spent')) {
+    db.exec("ALTER TABLE campaigns ADD COLUMN budget_spent REAL DEFAULT 0");
+    console.log('✅ Added budget_spent column to campaigns');
+  }
+  if (!campaignCols.includes('revenue')) {
+    db.exec("ALTER TABLE campaigns ADD COLUMN revenue REAL DEFAULT 0");
+    console.log('✅ Added revenue column to campaigns');
+  }
+  if (!campaignCols.includes('impressions')) {
+    db.exec("ALTER TABLE campaigns ADD COLUMN impressions INTEGER DEFAULT 0");
+    console.log('✅ Added impressions column to campaigns');
+  }
+  if (!campaignCols.includes('clicks')) {
+    db.exec("ALTER TABLE campaigns ADD COLUMN clicks INTEGER DEFAULT 0");
+    console.log('✅ Added clicks column to campaigns');
+  }
+  if (!campaignCols.includes('conversions')) {
+    db.exec("ALTER TABLE campaigns ADD COLUMN conversions INTEGER DEFAULT 0");
+    console.log('✅ Added conversions column to campaigns');
+  }
+  if (!campaignCols.includes('cost_per_click')) {
+    db.exec("ALTER TABLE campaigns ADD COLUMN cost_per_click REAL DEFAULT 0");
+    console.log('✅ Added cost_per_click column to campaigns');
+  }
+  if (!campaignCols.includes('notes')) {
+    db.exec("ALTER TABLE campaigns ADD COLUMN notes TEXT DEFAULT ''");
+    console.log('✅ Added notes column to campaigns');
+  }
+
+  // Add track_id to posts
+  const postCols = db.prepare("PRAGMA table_info(posts)").all().map(c => c.name);
+  if (!postCols.includes('track_id')) {
+    db.exec("ALTER TABLE posts ADD COLUMN track_id INTEGER REFERENCES campaign_tracks(id)");
+    console.log('✅ Added track_id column to posts');
+  }
+  if (!postCols.includes('campaign_id')) {
+    db.exec("ALTER TABLE posts ADD COLUMN campaign_id INTEGER REFERENCES campaigns(id)");
+    console.log('✅ Added campaign_id column to posts');
+  }
+  if (!postCols.includes('platforms')) {
+    // Add platforms column, migrate existing platform values
+    db.exec("ALTER TABLE posts ADD COLUMN platforms TEXT DEFAULT '[]'");
+    // Migrate: copy single platform value into platforms JSON array
+    const rows = db.prepare("SELECT id, platform FROM posts WHERE platform IS NOT NULL AND platform != ''").all();
+    const migrate = db.prepare("UPDATE posts SET platforms = ? WHERE id = ?");
+    for (const row of rows) {
+      migrate.run(JSON.stringify([row.platform]), row.id);
+    }
+    console.log(`✅ Added platforms column to posts, migrated ${rows.length} rows`);
+  }
+
+  // Add campaign_id to assets
+  const assetCols = db.prepare("PRAGMA table_info(assets)").all().map(c => c.name);
+  if (!assetCols.includes('campaign_id')) {
+    db.exec("ALTER TABLE assets ADD COLUMN campaign_id INTEGER REFERENCES campaigns(id)");
+    console.log('✅ Added campaign_id column to assets');
+  }
+
+  // ─── Link users to team_members ───
+  const userCols = db.prepare("PRAGMA table_info(users)").all().map(c => c.name);
+  if (!userCols.includes('team_member_id')) {
+    db.exec("ALTER TABLE users ADD COLUMN team_member_id INTEGER REFERENCES team_members(id)");
+    console.log('✅ Added team_member_id column to users');
+  }
+
+  // ─── Post attachments table ───
+  db.exec(`
+    CREATE TABLE IF NOT EXISTS post_attachments (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      post_id INTEGER NOT NULL REFERENCES posts(id) ON DELETE CASCADE,
+      filename TEXT NOT NULL,
+      original_name TEXT,
+      mime_type TEXT,
+      size INTEGER,
+      url TEXT,
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+  `);
+
+  // ─── Publication links column on posts ───
+  if (!postCols.includes('publication_links')) {
+    db.exec("ALTER TABLE posts ADD COLUMN publication_links TEXT DEFAULT '[]'");
+    console.log('✅ Added publication_links column to posts');
+  }
+
+  // ─── Merge team_members into users ───
+  if (!userCols.includes('team_role')) {
+    db.exec("ALTER TABLE users ADD COLUMN team_role TEXT");
+    console.log('✅ Added team_role column to users');
+  }
+  if (!userCols.includes('brands')) {
+    db.exec("ALTER TABLE users ADD COLUMN brands TEXT DEFAULT '[]'");
+    console.log('✅ Added brands column to users');
+  }
+  if (!userCols.includes('phone')) {
+    db.exec("ALTER TABLE users ADD COLUMN phone TEXT");
+    console.log('✅ Added phone column to users');
+  }
+  if (!userCols.includes('tutorial_completed')) {
+    db.exec("ALTER TABLE users ADD COLUMN tutorial_completed INTEGER DEFAULT 0");
+    console.log('✅ Added tutorial_completed column to users');
+  }
+
+  // Migrate team_members to users (one-time migration)
+  const teamMembers = db.prepare('SELECT * FROM team_members').all();
+  const defaultPasswordHash = bcrypt.hashSync('changeme123', 10);
+  
+  for (const tm of teamMembers) {
+    // Skip team_member id=9 (Fahed) - he's already user id=1
+    if (tm.id === 9) {
+      // Just update his team_role and brands
+      db.prepare('UPDATE users SET team_role = ?, brands = ?, team_member_id = ? WHERE id = 1')
+        .run(tm.role, tm.brands, tm.id);
+      continue;
+    }
+    
+    // Check if user already exists with this team_member_id
+    const existingUser = db.prepare('SELECT id FROM users WHERE team_member_id = ?').get(tm.id);
+    if (existingUser) {
+      // User exists, just update team_role and brands
+      db.prepare('UPDATE users SET team_role = ?, brands = ?, phone = ? WHERE id = ?')
+        .run(tm.role, tm.brands, tm.phone || null, existingUser.id);
+    } else {
+      // Create new user for this team member
+      db.prepare(`
+        INSERT INTO users (name, email, password_hash, role, team_role, brands, phone, team_member_id)
+        VALUES (?, ?, ?, 'contributor', ?, ?, ?, ?)
+      `).run(
+        tm.name,
+        tm.email,
+        defaultPasswordHash,
+        tm.role,
+        tm.brands,
+        tm.phone || null,
+        tm.id
+      );
+      console.log(`✅ Created user account for team member: ${tm.name}`);
+    }
+  }
+
+  // Seed data only if tables are empty
+  const memberCount = db.prepare('SELECT COUNT(*) as count FROM team_members').get().count;
+  if (memberCount === 0) {
+    seedData();
+  }
+
+  // Seed default superadmin if no users exist
+  const userCount = db.prepare('SELECT COUNT(*) as count FROM users').get().count;
+  if (userCount === 0) {
+    seedDefaultUser();
+  }
+}
+
+function seedData() {
+  const allBrands = JSON.stringify([
+    'Samaya Investment', 'Hira Cultural District', 'Holy Quran Museum',
+    'Al-Safiya Museum', 'Hayhala', 'Jabal Thawr', 'Coffee Chain', 'Taibah Gifts'
+  ]);
+  const someBrands = JSON.stringify([
+    'Samaya Investment', 'Hira Cultural District', 'Holy Quran Museum', 'Al-Safiya Museum'
+  ]);
+  const mostAccounts = JSON.stringify([
+    'Samaya Investment', 'Hira Cultural District', 'Holy Quran Museum',
+    'Al-Safiya Museum', 'Hayhala', 'Jabal Thawr', 'Coffee Chain'
+  ]);
+  const religiousExhibitions = JSON.stringify([
+    'Holy Quran Museum', 'Al-Safiya Museum', 'Jabal Thawr'
+  ]);
+
+  const insertMember = db.prepare(`
+    INSERT INTO team_members (name, email, role, brands) VALUES (?, ?, ?, ?)
+  `);
+
+  const members = [
+    ['Dr. Muhammad Al-Sayed', 'muhammad.alsayed@samaya.sa', 'approver', allBrands],
+    ['Dr. Fahd Al-Thumairi', 'fahd.thumairi@samaya.sa', 'approver', someBrands],
+    ['Fahda Abdul Aziz', 'fahda@samaya.sa', 'publisher', mostAccounts],
+    ['Sara Al-Zahrani', 'sara@samaya.sa', 'content_creator', JSON.stringify(['Samaya Investment', 'Hira Cultural District', 'Coffee Chain'])],
+    ['Noura', 'noura@samaya.sa', 'content_creator', JSON.stringify(['Samaya Investment', 'Hira Cultural District', 'Hayhala', 'Taibah Gifts'])],
+    ['Saeed Ghanem', 'saeed@samaya.sa', 'content_creator', religiousExhibitions],
+    ['Anas Mater', 'anas@samaya.sa', 'producer', JSON.stringify(['Samaya Investment', 'Hira Cultural District'])],
+    ['Muhammad Nu\'man', 'numan@samaya.sa', 'manager', JSON.stringify(['Google Maps'])],
+    ['Fahed', 'fahed@samaya.sa', 'manager', allBrands],
+  ];
+
+  const insertMembers = db.transaction(() => {
+    for (const m of members) {
+      insertMember.run(...m);
+    }
+  });
+  insertMembers();
+
+  // Seed brands
+  const insertBrand = db.prepare(`
+    INSERT INTO brands (name, priority, color, icon) VALUES (?, ?, ?, ?)
+  `);
+
+  const brands = [
+    ['Samaya Investment', 1, '#1E3A5F', '🏢'],
+    ['Hira Cultural District', 1, '#8B4513', '🏛️'],
+    ['Holy Quran Museum', 1, '#2E7D32', '📖'],
+    ['Al-Safiya Museum', 1, '#6A1B9A', '🏺'],
+    ['Hayhala', 1, '#C62828', '🎭'],
+    ['Jabal Thawr', 1, '#4E342E', '⛰️'],
+    ['Coffee Chain', 2, '#795548', '☕'],
+    ['Taibah Gifts', 3, '#E65100', '🎁'],
+  ];
+
+  const insertBrands = db.transaction(() => {
+    for (const b of brands) {
+      insertBrand.run(...b);
+    }
+  });
+  insertBrands();
+
+  console.log('✅ Database seeded with team members and brands');
+}
+
+function seedDefaultUser() {
+  const passwordHash = bcrypt.hashSync('admin123', 10);
+  const insertUser = db.prepare(`
+    INSERT INTO users (name, email, password_hash, role) VALUES (?, ?, ?, ?)
+  `);
+  insertUser.run('Fahed Muhaidi', 'f.mahidi@samayainvest.com', passwordHash, 'superadmin');
+  console.log('✅ Default superadmin created (email: f.mahidi@samayainvest.com, password: admin123)');
+}
+
+module.exports = { db, initialize };
diff --git a/server/marketing.db b/server/marketing.db
new file mode 100644
index 0000000..b8041df
Binary files /dev/null and b/server/marketing.db differ
diff --git a/server/marketing.db-shm b/server/marketing.db-shm
new file mode 100644
index 0000000..7b0d956
Binary files /dev/null and b/server/marketing.db-shm differ
diff --git a/server/marketing.db-wal b/server/marketing.db-wal
new file mode 100644
index 0000000..fd98fe9
Binary files /dev/null and b/server/marketing.db-wal differ
diff --git a/server/node_modules/.bin/color-support b/server/node_modules/.bin/color-support
new file mode 120000
index 0000000..fcbcb28
--- /dev/null
+++ b/server/node_modules/.bin/color-support
@@ -0,0 +1 @@
+../color-support/bin.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/mime b/server/node_modules/.bin/mime
new file mode 120000
index 0000000..fbb7ee0
--- /dev/null
+++ b/server/node_modules/.bin/mime
@@ -0,0 +1 @@
+../mime/cli.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/mkdirp b/server/node_modules/.bin/mkdirp
new file mode 120000
index 0000000..017896c
--- /dev/null
+++ b/server/node_modules/.bin/mkdirp
@@ -0,0 +1 @@
+../mkdirp/bin/cmd.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/node-gyp b/server/node_modules/.bin/node-gyp
new file mode 120000
index 0000000..9b31a4f
--- /dev/null
+++ b/server/node_modules/.bin/node-gyp
@@ -0,0 +1 @@
+../node-gyp/bin/node-gyp.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/node-gyp-build b/server/node_modules/.bin/node-gyp-build
new file mode 120000
index 0000000..671c6eb
--- /dev/null
+++ b/server/node_modules/.bin/node-gyp-build
@@ -0,0 +1 @@
+../node-gyp-build/bin.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/node-gyp-build-optional b/server/node_modules/.bin/node-gyp-build-optional
new file mode 120000
index 0000000..46d347e
--- /dev/null
+++ b/server/node_modules/.bin/node-gyp-build-optional
@@ -0,0 +1 @@
+../node-gyp-build/optional.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/node-gyp-build-test b/server/node_modules/.bin/node-gyp-build-test
new file mode 120000
index 0000000..d11de1b
--- /dev/null
+++ b/server/node_modules/.bin/node-gyp-build-test
@@ -0,0 +1 @@
+../node-gyp-build/build-test.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/node-which b/server/node_modules/.bin/node-which
new file mode 120000
index 0000000..6f8415e
--- /dev/null
+++ b/server/node_modules/.bin/node-which
@@ -0,0 +1 @@
+../which/bin/node-which
\ No newline at end of file
diff --git a/server/node_modules/.bin/nopt b/server/node_modules/.bin/nopt
new file mode 120000
index 0000000..6b6566e
--- /dev/null
+++ b/server/node_modules/.bin/nopt
@@ -0,0 +1 @@
+../nopt/bin/nopt.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/prebuild-install b/server/node_modules/.bin/prebuild-install
new file mode 120000
index 0000000..12a458d
--- /dev/null
+++ b/server/node_modules/.bin/prebuild-install
@@ -0,0 +1 @@
+../prebuild-install/bin.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/rc b/server/node_modules/.bin/rc
new file mode 120000
index 0000000..48b3cda
--- /dev/null
+++ b/server/node_modules/.bin/rc
@@ -0,0 +1 @@
+../rc/cli.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/rimraf b/server/node_modules/.bin/rimraf
new file mode 120000
index 0000000..4cd49a4
--- /dev/null
+++ b/server/node_modules/.bin/rimraf
@@ -0,0 +1 @@
+../rimraf/bin.js
\ No newline at end of file
diff --git a/server/node_modules/.bin/semver b/server/node_modules/.bin/semver
new file mode 120000
index 0000000..5aaadf4
--- /dev/null
+++ b/server/node_modules/.bin/semver
@@ -0,0 +1 @@
+../semver/bin/semver.js
\ No newline at end of file
diff --git a/server/node_modules/.package-lock.json b/server/node_modules/.package-lock.json
new file mode 100644
index 0000000..13f7f52
--- /dev/null
+++ b/server/node_modules/.package-lock.json
@@ -0,0 +1,2628 @@
+{
+  "name": "marketing-app-server",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "node_modules/@gar/promisify": {
+      "version": "1.1.3",
+      "resolved": "https://registry.npmjs.org/@gar/promisify/-/promisify-1.1.3.tgz",
+      "integrity": "sha512-k2Ty1JcVojjJFwrg/ThKi2ujJ7XNLYaFGNB/bWT9wGR+oSMJHMa5w+CUq6p/pVrKeNNgA7pCqEcjSnHVoqJQFw==",
+      "license": "MIT",
+      "optional": true
+    },
+    "node_modules/@npmcli/fs": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/@npmcli/fs/-/fs-1.1.1.tgz",
+      "integrity": "sha512-8KG5RD0GVP4ydEzRn/I4BNDuxDtqVbOdm8675T49OIG/NGhaK0pjPX7ZcDlvKYbA+ulvVK3ztfcF4uBdOxuJbQ==",
+      "license": "ISC",
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diff --git a/server/node_modules/@gar/promisify/LICENSE.md b/server/node_modules/@gar/promisify/LICENSE.md
new file mode 100644
index 0000000..64f7732
--- /dev/null
+++ b/server/node_modules/@gar/promisify/LICENSE.md
@@ -0,0 +1,10 @@
+The MIT License (MIT)
+
+Copyright © 2020-2022 Michael Garvin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/@gar/promisify/README.md b/server/node_modules/@gar/promisify/README.md
new file mode 100644
index 0000000..465c546
--- /dev/null
+++ b/server/node_modules/@gar/promisify/README.md
@@ -0,0 +1,65 @@
+# @gar/promisify
+
+### Promisify an entire object or class instance
+
+This module leverages es6 Proxy and Reflect to promisify every function in an
+object or class instance.
+
+It assumes the callback that the function is expecting is the last
+parameter, and that it is an error-first callback with only one value,
+i.e. `(err, value) => ...`. This mirrors node's `util.promisify` method.
+
+In order that you can use it as a one-stop-shop for all your promisify
+needs, you can also pass it a function.  That function will be
+promisified as normal using node's built-in `util.promisify` method.
+
+[node's custom promisified
+functions](https://nodejs.org/api/util.html#util_custom_promisified_functions)
+will also be mirrored, further allowing this to be a drop-in replacement
+for the built-in `util.promisify`.
+
+### Examples
+
+Promisify an entire object
+
+```javascript
+
+const promisify = require('@gar/promisify')
+
+class Foo {
+  constructor (attr) {
+    this.attr = attr
+  }
+
+  double (input, cb) {
+    cb(null, input * 2)
+  }
+
+const foo = new Foo('baz')
+const promisified = promisify(foo)
+
+console.log(promisified.attr)
+console.log(await promisified.double(1024))
+```
+
+Promisify a function
+
+```javascript
+
+const promisify = require('@gar/promisify')
+
+function foo (a, cb) {
+  if (a !== 'bad') {
+    return cb(null, 'ok')
+  }
+  return cb('not ok')
+}
+
+const promisified = promisify(foo)
+
+// This will resolve to 'ok'
+promisified('good')
+
+// this will reject
+promisified('bad')
+```
diff --git a/server/node_modules/@gar/promisify/index.js b/server/node_modules/@gar/promisify/index.js
new file mode 100644
index 0000000..d0be95f
--- /dev/null
+++ b/server/node_modules/@gar/promisify/index.js
@@ -0,0 +1,36 @@
+'use strict'
+
+const { promisify } = require('util')
+
+const handler = {
+  get: function (target, prop, receiver) {
+    if (typeof target[prop] !== 'function') {
+      return target[prop]
+    }
+    if (target[prop][promisify.custom]) {
+      return function () {
+        return Reflect.get(target, prop, receiver)[promisify.custom].apply(target, arguments)
+      }
+    }
+    return function () {
+      return new Promise((resolve, reject) => {
+        Reflect.get(target, prop, receiver).apply(target, [...arguments, function (err, result) {
+          if (err) {
+            return reject(err)
+          }
+          resolve(result)
+        }])
+      })
+    }
+  }
+}
+
+module.exports = function (thingToPromisify) {
+  if (typeof thingToPromisify === 'function') {
+    return promisify(thingToPromisify)
+  }
+  if (typeof thingToPromisify === 'object') {
+    return new Proxy(thingToPromisify, handler)
+  }
+  throw new TypeError('Can only promisify functions or objects')
+}
diff --git a/server/node_modules/@gar/promisify/package.json b/server/node_modules/@gar/promisify/package.json
new file mode 100644
index 0000000..d0ce69b
--- /dev/null
+++ b/server/node_modules/@gar/promisify/package.json
@@ -0,0 +1,32 @@
+{
+  "name": "@gar/promisify",
+  "version": "1.1.3",
+  "description": "Promisify an entire class or object",
+  "main": "index.js",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/wraithgar/gar-promisify.git"
+  },
+  "scripts": {
+    "lint": "standard",
+    "lint:fix": "standard --fix",
+    "test": "lab -a @hapi/code -t 100",
+    "posttest": "npm run lint"
+  },
+  "files": [
+    "index.js"
+  ],
+  "keywords": [
+    "promisify",
+    "all",
+    "class",
+    "object"
+  ],
+  "author": "Gar <gar+npm@danger.computer>",
+  "license": "MIT",
+  "devDependencies": {
+    "@hapi/code": "^8.0.1",
+    "@hapi/lab": "^24.1.0",
+    "standard": "^16.0.3"
+  }
+}
diff --git a/server/node_modules/@npmcli/fs/LICENSE.md b/server/node_modules/@npmcli/fs/LICENSE.md
new file mode 100644
index 0000000..5fc208f
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/LICENSE.md
@@ -0,0 +1,20 @@
+
+
+ISC License
+
+Copyright npm, Inc.
+
+Permission to use, copy, modify, and/or distribute this
+software for any purpose with or without fee is hereby
+granted, provided that the above copyright notice and this
+permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND NPM DISCLAIMS ALL
+WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+EVENT SHALL NPM BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/@npmcli/fs/README.md b/server/node_modules/@npmcli/fs/README.md
new file mode 100644
index 0000000..bc71a11
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/README.md
@@ -0,0 +1,60 @@
+# @npmcli/fs
+
+polyfills, and extensions, of the core `fs` module.
+
+## Features
+
+- all exposed functions return promises
+- `fs.rm` polyfill for node versions < 14.14.0
+- `fs.mkdir` polyfill adding support for the `recursive` and `force` options in node versions < 10.12.0
+- `fs.copyFile` extended to accept an `owner` option
+- `fs.mkdir` extended to accept an `owner` option
+- `fs.mkdtemp` extended to accept an `owner` option
+- `fs.writeFile` extended to accept an `owner` option
+- `fs.withTempDir` added
+- `fs.cp` polyfill for node < 16.7.0
+
+## The `owner` option
+
+The `copyFile`, `mkdir`, `mkdtemp`, `writeFile`, and `withTempDir` functions
+all accept a new `owner` property in their options. It can be used in two ways:
+
+- `{ owner: { uid: 100, gid: 100 } }` - set the `uid` and `gid` explicitly
+- `{ owner: 100 }` - use one value, will set both `uid` and `gid` the same
+
+The special string `'inherit'` may be passed instead of a number, which will
+cause this module to automatically determine the correct `uid` and/or `gid`
+from the nearest existing parent directory of the target.
+
+## `fs.withTempDir(root, fn, options) -> Promise`
+
+### Parameters
+
+- `root`: the directory in which to create the temporary directory
+- `fn`: a function that will be called with the path to the temporary directory
+- `options`
+  - `tmpPrefix`: a prefix to be used in the generated directory name
+
+### Usage
+
+The `withTempDir` function creates a temporary directory, runs the provided
+function (`fn`), then removes the temporary directory and resolves or rejects
+based on the result of `fn`.
+
+```js
+const fs = require('@npmcli/fs')
+const os = require('os')
+
+// this function will be called with the full path to the temporary directory
+// it is called with `await` behind the scenes, so can be async if desired.
+const myFunction = async (tempPath) => {
+  return 'done!'
+}
+
+const main = async () => {
+  const result = await fs.withTempDir(os.tmpdir(), myFunction)
+  // result === 'done!'
+}
+
+main()
+```
diff --git a/server/node_modules/@npmcli/fs/lib/common/file-url-to-path/index.js b/server/node_modules/@npmcli/fs/lib/common/file-url-to-path/index.js
new file mode 100644
index 0000000..7755d1c
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/common/file-url-to-path/index.js
@@ -0,0 +1,17 @@
+const url = require('url')
+
+const node = require('../node.js')
+const polyfill = require('./polyfill.js')
+
+const useNative = node.satisfies('>=10.12.0')
+
+const fileURLToPath = (path) => {
+  // the polyfill is tested separately from this module, no need to hack
+  // process.version to try to trigger it just for coverage
+  // istanbul ignore next
+  return useNative
+    ? url.fileURLToPath(path)
+    : polyfill(path)
+}
+
+module.exports = fileURLToPath
diff --git a/server/node_modules/@npmcli/fs/lib/common/file-url-to-path/polyfill.js b/server/node_modules/@npmcli/fs/lib/common/file-url-to-path/polyfill.js
new file mode 100644
index 0000000..6cc90f0
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/common/file-url-to-path/polyfill.js
@@ -0,0 +1,121 @@
+const { URL, domainToUnicode } = require('url')
+
+const CHAR_LOWERCASE_A = 97
+const CHAR_LOWERCASE_Z = 122
+
+const isWindows = process.platform === 'win32'
+
+class ERR_INVALID_FILE_URL_HOST extends TypeError {
+  constructor (platform) {
+    super(`File URL host must be "localhost" or empty on ${platform}`)
+    this.code = 'ERR_INVALID_FILE_URL_HOST'
+  }
+
+  toString () {
+    return `${this.name} [${this.code}]: ${this.message}`
+  }
+}
+
+class ERR_INVALID_FILE_URL_PATH extends TypeError {
+  constructor (msg) {
+    super(`File URL path ${msg}`)
+    this.code = 'ERR_INVALID_FILE_URL_PATH'
+  }
+
+  toString () {
+    return `${this.name} [${this.code}]: ${this.message}`
+  }
+}
+
+class ERR_INVALID_ARG_TYPE extends TypeError {
+  constructor (name, actual) {
+    super(`The "${name}" argument must be one of type string or an instance ` +
+      `of URL. Received type ${typeof actual} ${actual}`)
+    this.code = 'ERR_INVALID_ARG_TYPE'
+  }
+
+  toString () {
+    return `${this.name} [${this.code}]: ${this.message}`
+  }
+}
+
+class ERR_INVALID_URL_SCHEME extends TypeError {
+  constructor (expected) {
+    super(`The URL must be of scheme ${expected}`)
+    this.code = 'ERR_INVALID_URL_SCHEME'
+  }
+
+  toString () {
+    return `${this.name} [${this.code}]: ${this.message}`
+  }
+}
+
+const isURLInstance = (input) => {
+  return input != null && input.href && input.origin
+}
+
+const getPathFromURLWin32 = (url) => {
+  const hostname = url.hostname
+  let pathname = url.pathname
+  for (let n = 0; n < pathname.length; n++) {
+    if (pathname[n] === '%') {
+      const third = pathname.codePointAt(n + 2) | 0x20
+      if ((pathname[n + 1] === '2' && third === 102) ||
+        (pathname[n + 1] === '5' && third === 99)) {
+        throw new ERR_INVALID_FILE_URL_PATH('must not include encoded \\ or / characters')
+      }
+    }
+  }
+
+  pathname = pathname.replace(/\//g, '\\')
+  pathname = decodeURIComponent(pathname)
+  if (hostname !== '') {
+    return `\\\\${domainToUnicode(hostname)}${pathname}`
+  }
+
+  const letter = pathname.codePointAt(1) | 0x20
+  const sep = pathname[2]
+  if (letter < CHAR_LOWERCASE_A || letter > CHAR_LOWERCASE_Z ||
+    (sep !== ':')) {
+    throw new ERR_INVALID_FILE_URL_PATH('must be absolute')
+  }
+
+  return pathname.slice(1)
+}
+
+const getPathFromURLPosix = (url) => {
+  if (url.hostname !== '') {
+    throw new ERR_INVALID_FILE_URL_HOST(process.platform)
+  }
+
+  const pathname = url.pathname
+
+  for (let n = 0; n < pathname.length; n++) {
+    if (pathname[n] === '%') {
+      const third = pathname.codePointAt(n + 2) | 0x20
+      if (pathname[n + 1] === '2' && third === 102) {
+        throw new ERR_INVALID_FILE_URL_PATH('must not include encoded / characters')
+      }
+    }
+  }
+
+  return decodeURIComponent(pathname)
+}
+
+const fileURLToPath = (path) => {
+  if (typeof path === 'string') {
+    path = new URL(path)
+  } else if (!isURLInstance(path)) {
+    throw new ERR_INVALID_ARG_TYPE('path', ['string', 'URL'], path)
+  }
+
+  if (path.protocol !== 'file:') {
+    throw new ERR_INVALID_URL_SCHEME('file')
+  }
+
+  return isWindows
+    ? getPathFromURLWin32(path)
+    : getPathFromURLPosix(path)
+}
+
+module.exports = fileURLToPath
diff --git a/server/node_modules/@npmcli/fs/lib/common/get-options.js b/server/node_modules/@npmcli/fs/lib/common/get-options.js
new file mode 100644
index 0000000..cb5982f
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/common/get-options.js
@@ -0,0 +1,20 @@
+// given an input that may or may not be an object, return an object that has
+// a copy of every defined property listed in 'copy'. if the input is not an
+// object, assign it to the property named by 'wrap'
+const getOptions = (input, { copy, wrap }) => {
+  const result = {}
+
+  if (input && typeof input === 'object') {
+    for (const prop of copy) {
+      if (input[prop] !== undefined) {
+        result[prop] = input[prop]
+      }
+    }
+  } else {
+    result[wrap] = input
+  }
+
+  return result
+}
+
+module.exports = getOptions
diff --git a/server/node_modules/@npmcli/fs/lib/common/node.js b/server/node_modules/@npmcli/fs/lib/common/node.js
new file mode 100644
index 0000000..4d13bc0
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/common/node.js
@@ -0,0 +1,9 @@
+const semver = require('semver')
+
+const satisfies = (range) => {
+  return semver.satisfies(process.version, range, { includePrerelease: true })
+}
+
+module.exports = {
+  satisfies,
+}
diff --git a/server/node_modules/@npmcli/fs/lib/common/owner.js b/server/node_modules/@npmcli/fs/lib/common/owner.js
new file mode 100644
index 0000000..e3468b0
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/common/owner.js
@@ -0,0 +1,92 @@
+const { dirname, resolve } = require('path')
+
+const fileURLToPath = require('./file-url-to-path/index.js')
+const fs = require('../fs.js')
+
+// given a path, find the owner of the nearest parent
+const find = async (path) => {
+  // if we have no getuid, permissions are irrelevant on this platform
+  if (!process.getuid) {
+    return {}
+  }
+
+  // fs methods accept URL objects with a scheme of file: so we need to unwrap
+  // those into an actual path string before we can resolve it
+  const resolved = path != null && path.href && path.origin
+    ? resolve(fileURLToPath(path))
+    : resolve(path)
+
+  let stat
+
+  try {
+    stat = await fs.lstat(resolved)
+  } finally {
+    // if we got a stat, return its contents
+    if (stat) {
+      return { uid: stat.uid, gid: stat.gid }
+    }
+
+    // try the parent directory
+    if (resolved !== dirname(resolved)) {
+      return find(dirname(resolved))
+    }
+
+    // no more parents, never got a stat, just return an empty object
+    return {}
+  }
+}
+
+// given a path, uid, and gid update the ownership of the path if necessary
+const update = async (path, uid, gid) => {
+  // nothing to update, just exit
+  if (uid === undefined && gid === undefined) {
+    return
+  }
+
+  try {
+    // see if the permissions are already the same, if they are we don't
+    // need to do anything, so return early
+    const stat = await fs.stat(path)
+    if (uid === stat.uid && gid === stat.gid) {
+      return
+    }
+  } catch (err) {}
+
+  try {
+    await fs.chown(path, uid, gid)
+  } catch (err) {}
+}
+
+// accepts a `path` and the `owner` property of an options object and normalizes
+// it into an object with numerical `uid` and `gid`
+const validate = async (path, input) => {
+  let uid
+  let gid
+
+  if (typeof input === 'string' || typeof input === 'number') {
+    uid = input
+    gid = input
+  } else if (input && typeof input === 'object') {
+    uid = input.uid
+    gid = input.gid
+  }
+
+  if (uid === 'inherit' || gid === 'inherit') {
+    const owner = await find(path)
+    if (uid === 'inherit') {
+      uid = owner.uid
+    }
+
+    if (gid === 'inherit') {
+      gid = owner.gid
+    }
+  }
+
+  return { uid, gid }
+}
+
+module.exports = {
+  find,
+  update,
+  validate,
+}
diff --git a/server/node_modules/@npmcli/fs/lib/copy-file.js b/server/node_modules/@npmcli/fs/lib/copy-file.js
new file mode 100644
index 0000000..d9875ab
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/copy-file.js
@@ -0,0 +1,22 @@
+const fs = require('./fs.js')
+const getOptions = require('./common/get-options.js')
+const owner = require('./common/owner.js')
+
+const copyFile = async (src, dest, opts) => {
+  const options = getOptions(opts, {
+    copy: ['mode', 'owner'],
+    wrap: 'mode',
+  })
+
+  const { uid, gid } = await owner.validate(dest, options.owner)
+
+  // the node core method as of 16.5.0 does not support the mode being in an
+  // object, so we have to pass the mode value directly
+  const result = await fs.copyFile(src, dest, options.mode)
+
+  await owner.update(dest, uid, gid)
+
+  return result
+}
+
+module.exports = copyFile
diff --git a/server/node_modules/@npmcli/fs/lib/cp/LICENSE b/server/node_modules/@npmcli/fs/lib/cp/LICENSE
new file mode 100644
index 0000000..93546df
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/cp/LICENSE
@@ -0,0 +1,15 @@
+(The MIT License)
+
+Copyright (c) 2011-2017 JP Richardson
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files
+(the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify,
+ merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
+OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/@npmcli/fs/lib/cp/index.js b/server/node_modules/@npmcli/fs/lib/cp/index.js
new file mode 100644
index 0000000..5da4739
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/cp/index.js
@@ -0,0 +1,22 @@
+const fs = require('../fs.js')
+const getOptions = require('../common/get-options.js')
+const node = require('../common/node.js')
+const polyfill = require('./polyfill.js')
+
+// node 16.7.0 added fs.cp
+const useNative = node.satisfies('>=16.7.0')
+
+const cp = async (src, dest, opts) => {
+  const options = getOptions(opts, {
+    copy: ['dereference', 'errorOnExist', 'filter', 'force', 'preserveTimestamps', 'recursive'],
+  })
+
+  // the polyfill is tested separately from this module, no need to hack
+  // process.version to try to trigger it just for coverage
+  // istanbul ignore next
+  return useNative
+    ? fs.cp(src, dest, options)
+    : polyfill(src, dest, options)
+}
+
+module.exports = cp
diff --git a/server/node_modules/@npmcli/fs/lib/cp/polyfill.js b/server/node_modules/@npmcli/fs/lib/cp/polyfill.js
new file mode 100644
index 0000000..f83ccbf
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/cp/polyfill.js
@@ -0,0 +1,428 @@
+// this file is a modified version of the code in node 17.2.0
+// which is, in turn, a modified version of the fs-extra module on npm
+// node core changes:
+// - Use of the assert module has been replaced with core's error system.
+// - All code related to the glob dependency has been removed.
+// - Bring your own custom fs module is not currently supported.
+// - Some basic code cleanup.
+// changes here:
+// - remove all callback related code
+// - drop sync support
+// - change assertions back to non-internal methods (see options.js)
+// - throws ENOTDIR when rmdir gets an ENOENT for a path that exists in Windows
+'use strict'
+
+const {
+  ERR_FS_CP_DIR_TO_NON_DIR,
+  ERR_FS_CP_EEXIST,
+  ERR_FS_CP_EINVAL,
+  ERR_FS_CP_FIFO_PIPE,
+  ERR_FS_CP_NON_DIR_TO_DIR,
+  ERR_FS_CP_SOCKET,
+  ERR_FS_CP_SYMLINK_TO_SUBDIRECTORY,
+  ERR_FS_CP_UNKNOWN,
+  ERR_FS_EISDIR,
+  ERR_INVALID_ARG_TYPE,
+} = require('../errors.js')
+const {
+  constants: {
+    errno: {
+      EEXIST,
+      EISDIR,
+      EINVAL,
+      ENOTDIR,
+    },
+  },
+} = require('os')
+const {
+  chmod,
+  copyFile,
+  lstat,
+  mkdir,
+  readdir,
+  readlink,
+  stat,
+  symlink,
+  unlink,
+  utimes,
+} = require('../fs.js')
+const {
+  dirname,
+  isAbsolute,
+  join,
+  parse,
+  resolve,
+  sep,
+  toNamespacedPath,
+} = require('path')
+const { fileURLToPath } = require('url')
+
+const defaultOptions = {
+  dereference: false,
+  errorOnExist: false,
+  filter: undefined,
+  force: true,
+  preserveTimestamps: false,
+  recursive: false,
+}
+
+async function cp (src, dest, opts) {
+  if (opts != null && typeof opts !== 'object') {
+    throw new ERR_INVALID_ARG_TYPE('options', ['Object'], opts)
+  }
+  return cpFn(
+    toNamespacedPath(getValidatedPath(src)),
+    toNamespacedPath(getValidatedPath(dest)),
+    { ...defaultOptions, ...opts })
+}
+
+function getValidatedPath (fileURLOrPath) {
+  const path = fileURLOrPath != null && fileURLOrPath.href
+      && fileURLOrPath.origin
+    ? fileURLToPath(fileURLOrPath)
+    : fileURLOrPath
+  return path
+}
+
+async function cpFn (src, dest, opts) {
+  // Warn about using preserveTimestamps on 32-bit node
+  // istanbul ignore next
+  if (opts.preserveTimestamps && process.arch === 'ia32') {
+    const warning = 'Using the preserveTimestamps option in 32-bit ' +
+      'node is not recommended'
+    process.emitWarning(warning, 'TimestampPrecisionWarning')
+  }
+  const stats = await checkPaths(src, dest, opts)
+  const { srcStat, destStat } = stats
+  await checkParentPaths(src, srcStat, dest)
+  if (opts.filter) {
+    return handleFilter(checkParentDir, destStat, src, dest, opts)
+  }
+  return checkParentDir(destStat, src, dest, opts)
+}
+
+async function checkPaths (src, dest, opts) {
+  const { 0: srcStat, 1: destStat } = await getStats(src, dest, opts)
+  if (destStat) {
+    if (areIdentical(srcStat, destStat)) {
+      throw new ERR_FS_CP_EINVAL({
+        message: 'src and dest cannot be the same',
+        path: dest,
+        syscall: 'cp',
+        errno: EINVAL,
+      })
+    }
+    if (srcStat.isDirectory() && !destStat.isDirectory()) {
+      throw new ERR_FS_CP_DIR_TO_NON_DIR({
+        message: `cannot overwrite directory ${src} ` +
+            `with non-directory ${dest}`,
+        path: dest,
+        syscall: 'cp',
+        errno: EISDIR,
+      })
+    }
+    if (!srcStat.isDirectory() && destStat.isDirectory()) {
+      throw new ERR_FS_CP_NON_DIR_TO_DIR({
+        message: `cannot overwrite non-directory ${src} ` +
+            `with directory ${dest}`,
+        path: dest,
+        syscall: 'cp',
+        errno: ENOTDIR,
+      })
+    }
+  }
+
+  if (srcStat.isDirectory() && isSrcSubdir(src, dest)) {
+    throw new ERR_FS_CP_EINVAL({
+      message: `cannot copy ${src} to a subdirectory of self ${dest}`,
+      path: dest,
+      syscall: 'cp',
+      errno: EINVAL,
+    })
+  }
+  return { srcStat, destStat }
+}
+
+function areIdentical (srcStat, destStat) {
+  return destStat.ino && destStat.dev && destStat.ino === srcStat.ino &&
+    destStat.dev === srcStat.dev
+}
+
+function getStats (src, dest, opts) {
+  const statFunc = opts.dereference ?
+    (file) => stat(file, { bigint: true }) :
+    (file) => lstat(file, { bigint: true })
+  return Promise.all([
+    statFunc(src),
+    statFunc(dest).catch((err) => {
+      // istanbul ignore next: unsure how to cover.
+      if (err.code === 'ENOENT') {
+        return null
+      }
+      // istanbul ignore next: unsure how to cover.
+      throw err
+    }),
+  ])
+}
+
+async function checkParentDir (destStat, src, dest, opts) {
+  const destParent = dirname(dest)
+  const dirExists = await pathExists(destParent)
+  if (dirExists) {
+    return getStatsForCopy(destStat, src, dest, opts)
+  }
+  await mkdir(destParent, { recursive: true })
+  return getStatsForCopy(destStat, src, dest, opts)
+}
+
+function pathExists (dest) {
+  return stat(dest).then(
+    () => true,
+    // istanbul ignore next: not sure when this would occur
+    (err) => (err.code === 'ENOENT' ? false : Promise.reject(err)))
+}
+
+// Recursively check if dest parent is a subdirectory of src.
+// It works for all file types including symlinks since it
+// checks the src and dest inodes. It starts from the deepest
+// parent and stops once it reaches the src parent or the root path.
+async function checkParentPaths (src, srcStat, dest) {
+  const srcParent = resolve(dirname(src))
+  const destParent = resolve(dirname(dest))
+  if (destParent === srcParent || destParent === parse(destParent).root) {
+    return
+  }
+  let destStat
+  try {
+    destStat = await stat(destParent, { bigint: true })
+  } catch (err) {
+    // istanbul ignore else: not sure when this would occur
+    if (err.code === 'ENOENT') {
+      return
+    }
+    // istanbul ignore next: not sure when this would occur
+    throw err
+  }
+  if (areIdentical(srcStat, destStat)) {
+    throw new ERR_FS_CP_EINVAL({
+      message: `cannot copy ${src} to a subdirectory of self ${dest}`,
+      path: dest,
+      syscall: 'cp',
+      errno: EINVAL,
+    })
+  }
+  return checkParentPaths(src, srcStat, destParent)
+}
+
+const normalizePathToArray = (path) =>
+  resolve(path).split(sep).filter(Boolean)
+
+// Return true if dest is a subdir of src, otherwise false.
+// It only checks the path strings.
+function isSrcSubdir (src, dest) {
+  const srcArr = normalizePathToArray(src)
+  const destArr = normalizePathToArray(dest)
+  return srcArr.every((cur, i) => destArr[i] === cur)
+}
+
+async function handleFilter (onInclude, destStat, src, dest, opts, cb) {
+  const include = await opts.filter(src, dest)
+  if (include) {
+    return onInclude(destStat, src, dest, opts, cb)
+  }
+}
+
+function startCopy (destStat, src, dest, opts) {
+  if (opts.filter) {
+    return handleFilter(getStatsForCopy, destStat, src, dest, opts)
+  }
+  return getStatsForCopy(destStat, src, dest, opts)
+}
+
+async function getStatsForCopy (destStat, src, dest, opts) {
+  const statFn = opts.dereference ? stat : lstat
+  const srcStat = await statFn(src)
+  // istanbul ignore else: can't portably test FIFO
+  if (srcStat.isDirectory() && opts.recursive) {
+    return onDir(srcStat, destStat, src, dest, opts)
+  } else if (srcStat.isDirectory()) {
+    throw new ERR_FS_EISDIR({
+      message: `${src} is a directory (not copied)`,
+      path: src,
+      syscall: 'cp',
+      errno: EINVAL,
+    })
+  } else if (srcStat.isFile() ||
+            srcStat.isCharacterDevice() ||
+            srcStat.isBlockDevice()) {
+    return onFile(srcStat, destStat, src, dest, opts)
+  } else if (srcStat.isSymbolicLink()) {
+    return onLink(destStat, src, dest)
+  } else if (srcStat.isSocket()) {
+    throw new ERR_FS_CP_SOCKET({
+      message: `cannot copy a socket file: ${dest}`,
+      path: dest,
+      syscall: 'cp',
+      errno: EINVAL,
+    })
+  } else if (srcStat.isFIFO()) {
+    throw new ERR_FS_CP_FIFO_PIPE({
+      message: `cannot copy a FIFO pipe: ${dest}`,
+      path: dest,
+      syscall: 'cp',
+      errno: EINVAL,
+    })
+  }
+  // istanbul ignore next: should be unreachable
+  throw new ERR_FS_CP_UNKNOWN({
+    message: `cannot copy an unknown file type: ${dest}`,
+    path: dest,
+    syscall: 'cp',
+    errno: EINVAL,
+  })
+}
+
+function onFile (srcStat, destStat, src, dest, opts) {
+  if (!destStat) {
+    return _copyFile(srcStat, src, dest, opts)
+  }
+  return mayCopyFile(srcStat, src, dest, opts)
+}
+
+async function mayCopyFile (srcStat, src, dest, opts) {
+  if (opts.force) {
+    await unlink(dest)
+    return _copyFile(srcStat, src, dest, opts)
+  } else if (opts.errorOnExist) {
+    throw new ERR_FS_CP_EEXIST({
+      message: `${dest} already exists`,
+      path: dest,
+      syscall: 'cp',
+      errno: EEXIST,
+    })
+  }
+}
+
+async function _copyFile (srcStat, src, dest, opts) {
+  await copyFile(src, dest)
+  if (opts.preserveTimestamps) {
+    return handleTimestampsAndMode(srcStat.mode, src, dest)
+  }
+  return setDestMode(dest, srcStat.mode)
+}
+
+async function handleTimestampsAndMode (srcMode, src, dest) {
+  // Make sure the file is writable before setting the timestamp
+  // otherwise open fails with EPERM when invoked with 'r+'
+  // (through utimes call)
+  if (fileIsNotWritable(srcMode)) {
+    await makeFileWritable(dest, srcMode)
+    return setDestTimestampsAndMode(srcMode, src, dest)
+  }
+  return setDestTimestampsAndMode(srcMode, src, dest)
+}
+
+function fileIsNotWritable (srcMode) {
+  return (srcMode & 0o200) === 0
+}
+
+function makeFileWritable (dest, srcMode) {
+  return setDestMode(dest, srcMode | 0o200)
+}
+
+async function setDestTimestampsAndMode (srcMode, src, dest) {
+  await setDestTimestamps(src, dest)
+  return setDestMode(dest, srcMode)
+}
+
+function setDestMode (dest, srcMode) {
+  return chmod(dest, srcMode)
+}
+
+async function setDestTimestamps (src, dest) {
+  // The initial srcStat.atime cannot be trusted
+  // because it is modified by the read(2) system call
+  // (See https://nodejs.org/api/fs.html#fs_stat_time_values)
+  const updatedSrcStat = await stat(src)
+  return utimes(dest, updatedSrcStat.atime, updatedSrcStat.mtime)
+}
+
+function onDir (srcStat, destStat, src, dest, opts) {
+  if (!destStat) {
+    return mkDirAndCopy(srcStat.mode, src, dest, opts)
+  }
+  return copyDir(src, dest, opts)
+}
+
+async function mkDirAndCopy (srcMode, src, dest, opts) {
+  await mkdir(dest)
+  await copyDir(src, dest, opts)
+  return setDestMode(dest, srcMode)
+}
+
+async function copyDir (src, dest, opts) {
+  const dir = await readdir(src)
+  for (let i = 0; i < dir.length; i++) {
+    const item = dir[i]
+    const srcItem = join(src, item)
+    const destItem = join(dest, item)
+    const { destStat } = await checkPaths(srcItem, destItem, opts)
+    await startCopy(destStat, srcItem, destItem, opts)
+  }
+}
+
+async function onLink (destStat, src, dest) {
+  let resolvedSrc = await readlink(src)
+  if (!isAbsolute(resolvedSrc)) {
+    resolvedSrc = resolve(dirname(src), resolvedSrc)
+  }
+  if (!destStat) {
+    return symlink(resolvedSrc, dest)
+  }
+  let resolvedDest
+  try {
+    resolvedDest = await readlink(dest)
+  } catch (err) {
+    // Dest exists and is a regular file or directory,
+    // Windows may throw UNKNOWN error. If dest already exists,
+    // fs throws error anyway, so no need to guard against it here.
+    // istanbul ignore next: can only test on windows
+    if (err.code === 'EINVAL' || err.code === 'UNKNOWN') {
+      return symlink(resolvedSrc, dest)
+    }
+    // istanbul ignore next: should not be possible
+    throw err
+  }
+  if (!isAbsolute(resolvedDest)) {
+    resolvedDest = resolve(dirname(dest), resolvedDest)
+  }
+  if (isSrcSubdir(resolvedSrc, resolvedDest)) {
+    throw new ERR_FS_CP_EINVAL({
+      message: `cannot copy ${resolvedSrc} to a subdirectory of self ` +
+            `${resolvedDest}`,
+      path: dest,
+      syscall: 'cp',
+      errno: EINVAL,
+    })
+  }
+  // Do not copy if src is a subdir of dest since unlinking
+  // dest in this case would result in removing src contents
+  // and therefore a broken symlink would be created.
+  const srcStat = await stat(src)
+  if (srcStat.isDirectory() && isSrcSubdir(resolvedDest, resolvedSrc)) {
+    throw new ERR_FS_CP_SYMLINK_TO_SUBDIRECTORY({
+      message: `cannot overwrite ${resolvedDest} with ${resolvedSrc}`,
+      path: dest,
+      syscall: 'cp',
+      errno: EINVAL,
+    })
+  }
+  return copyLink(resolvedSrc, dest)
+}
+
+async function copyLink (resolvedSrc, dest) {
+  await unlink(dest)
+  return symlink(resolvedSrc, dest)
+}
+
+module.exports = cp
diff --git a/server/node_modules/@npmcli/fs/lib/errors.js b/server/node_modules/@npmcli/fs/lib/errors.js
new file mode 100644
index 0000000..1cd1e05
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/errors.js
@@ -0,0 +1,129 @@
+'use strict'
+const { inspect } = require('util')
+
+// adapted from node's internal/errors
+// https://github.com/nodejs/node/blob/c8a04049/lib/internal/errors.js
+
+// close copy of node's internal SystemError class.
+class SystemError {
+  constructor (code, prefix, context) {
+    // XXX context.code is undefined in all constructors used in cp/polyfill
+    // that may be a bug copied from node, maybe the constructor should use
+    // `code` not `errno`?  nodejs/node#41104
+    let message = `${prefix}: ${context.syscall} returned ` +
+                  `${context.code} (${context.message})`
+
+    if (context.path !== undefined) {
+      message += ` ${context.path}`
+    }
+    if (context.dest !== undefined) {
+      message += ` => ${context.dest}`
+    }
+
+    this.code = code
+    Object.defineProperties(this, {
+      name: {
+        value: 'SystemError',
+        enumerable: false,
+        writable: true,
+        configurable: true,
+      },
+      message: {
+        value: message,
+        enumerable: false,
+        writable: true,
+        configurable: true,
+      },
+      info: {
+        value: context,
+        enumerable: true,
+        configurable: true,
+        writable: false,
+      },
+      errno: {
+        get () {
+          return context.errno
+        },
+        set (value) {
+          context.errno = value
+        },
+        enumerable: true,
+        configurable: true,
+      },
+      syscall: {
+        get () {
+          return context.syscall
+        },
+        set (value) {
+          context.syscall = value
+        },
+        enumerable: true,
+        configurable: true,
+      },
+    })
+
+    if (context.path !== undefined) {
+      Object.defineProperty(this, 'path', {
+        get () {
+          return context.path
+        },
+        set (value) {
+          context.path = value
+        },
+        enumerable: true,
+        configurable: true,
+      })
+    }
+
+    if (context.dest !== undefined) {
+      Object.defineProperty(this, 'dest', {
+        get () {
+          return context.dest
+        },
+        set (value) {
+          context.dest = value
+        },
+        enumerable: true,
+        configurable: true,
+      })
+    }
+  }
+
+  toString () {
+    return `${this.name} [${this.code}]: ${this.message}`
+  }
+
+  [Symbol.for('nodejs.util.inspect.custom')] (_recurseTimes, ctx) {
+    return inspect(this, {
+      ...ctx,
+      getters: true,
+      customInspect: false,
+    })
+  }
+}
+
+function E (code, message) {
+  module.exports[code] = class NodeError extends SystemError {
+    constructor (ctx) {
+      super(code, message, ctx)
+    }
+  }
+}
+
+E('ERR_FS_CP_DIR_TO_NON_DIR', 'Cannot overwrite directory with non-directory')
+E('ERR_FS_CP_EEXIST', 'Target already exists')
+E('ERR_FS_CP_EINVAL', 'Invalid src or dest')
+E('ERR_FS_CP_FIFO_PIPE', 'Cannot copy a FIFO pipe')
+E('ERR_FS_CP_NON_DIR_TO_DIR', 'Cannot overwrite non-directory with directory')
+E('ERR_FS_CP_SOCKET', 'Cannot copy a socket file')
+E('ERR_FS_CP_SYMLINK_TO_SUBDIRECTORY', 'Cannot overwrite symlink in subdirectory of self')
+E('ERR_FS_CP_UNKNOWN', 'Cannot copy an unknown file type')
+E('ERR_FS_EISDIR', 'Path is a directory')
+
+module.exports.ERR_INVALID_ARG_TYPE = class ERR_INVALID_ARG_TYPE extends Error {
+  constructor (name, expected, actual) {
+    super()
+    this.code = 'ERR_INVALID_ARG_TYPE'
+    this.message = `The ${name} argument must be ${expected}. Received ${typeof actual}`
+  }
+}
diff --git a/server/node_modules/@npmcli/fs/lib/fs.js b/server/node_modules/@npmcli/fs/lib/fs.js
new file mode 100644
index 0000000..29e5fb5
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/fs.js
@@ -0,0 +1,8 @@
+const fs = require('fs')
+const promisify = require('@gar/promisify')
+
+// this module returns the core fs module wrapped in a proxy that promisifies
+// method calls within the getter. we keep it in a separate module so that the
+// overridden methods have a consistent way to get to promisified fs methods
+// without creating a circular dependency
+module.exports = promisify(fs)
diff --git a/server/node_modules/@npmcli/fs/lib/index.js b/server/node_modules/@npmcli/fs/lib/index.js
new file mode 100644
index 0000000..e40d748
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/index.js
@@ -0,0 +1,10 @@
+module.exports = {
+  ...require('./fs.js'),
+  copyFile: require('./copy-file.js'),
+  cp: require('./cp/index.js'),
+  mkdir: require('./mkdir/index.js'),
+  mkdtemp: require('./mkdtemp.js'),
+  rm: require('./rm/index.js'),
+  withTempDir: require('./with-temp-dir.js'),
+  writeFile: require('./write-file.js'),
+}
diff --git a/server/node_modules/@npmcli/fs/lib/mkdir/index.js b/server/node_modules/@npmcli/fs/lib/mkdir/index.js
new file mode 100644
index 0000000..04ff447
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/mkdir/index.js
@@ -0,0 +1,32 @@
+const fs = require('../fs.js')
+const getOptions = require('../common/get-options.js')
+const node = require('../common/node.js')
+const owner = require('../common/owner.js')
+
+const polyfill = require('./polyfill.js')
+
+// node 10.12.0 added the options parameter, which allows recursive and mode
+// properties to be passed
+const useNative = node.satisfies('>=10.12.0')
+
+// extends mkdir with the ability to specify an owner of the new dir
+const mkdir = async (path, opts) => {
+  const options = getOptions(opts, {
+    copy: ['mode', 'recursive', 'owner'],
+    wrap: 'mode',
+  })
+  const { uid, gid } = await owner.validate(path, options.owner)
+
+  // the polyfill is tested separately from this module, no need to hack
+  // process.version to try to trigger it just for coverage
+  // istanbul ignore next
+  const result = useNative
+    ? await fs.mkdir(path, options)
+    : await polyfill(path, options)
+
+  await owner.update(path, uid, gid)
+
+  return result
+}
+
+module.exports = mkdir
diff --git a/server/node_modules/@npmcli/fs/lib/mkdir/polyfill.js b/server/node_modules/@npmcli/fs/lib/mkdir/polyfill.js
new file mode 100644
index 0000000..4f8e6f0
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/mkdir/polyfill.js
@@ -0,0 +1,81 @@
+const { dirname } = require('path')
+
+const fileURLToPath = require('../common/file-url-to-path/index.js')
+const fs = require('../fs.js')
+
+const defaultOptions = {
+  mode: 0o777,
+  recursive: false,
+}
+
+const mkdir = async (path, opts) => {
+  const options = { ...defaultOptions, ...opts }
+
+  // if we're not in recursive mode, just call the real mkdir with the path and
+  // the mode option only
+  if (!options.recursive) {
+    return fs.mkdir(path, options.mode)
+  }
+
+  const makeDirectory = async (dir, mode) => {
+    // we can't use dirname directly since these functions support URL
+    // objects with the file: protocol as the path input, so first we get a
+    // string path, then we can call dirname on that
+    const parent = dir != null && dir.href && dir.origin
+      ? dirname(fileURLToPath(dir))
+      : dirname(dir)
+
+    // if the parent is the dir itself, try to create it. anything but EISDIR
+    // should be rethrown
+    if (parent === dir) {
+      try {
+        await fs.mkdir(dir, opts)
+      } catch (err) {
+        if (err.code !== 'EISDIR') {
+          throw err
+        }
+      }
+      return undefined
+    }
+
+    try {
+      await fs.mkdir(dir, mode)
+      return dir
+    } catch (err) {
+      // ENOENT means the parent wasn't there, so create that
+      if (err.code === 'ENOENT') {
+        const made = await makeDirectory(parent, mode)
+        await makeDirectory(dir, mode)
+        // return the shallowest path we created, i.e. the result of creating
+        // the parent
+        return made
+      }
+
+      // an EEXIST means there's already something there
+      // an EROFS means we have a read-only filesystem and can't create a dir
+      // any other error is fatal and we should give up now
+      if (err.code !== 'EEXIST' && err.code !== 'EROFS') {
+        throw err
+      }
+
+      // stat the directory, if the result is a directory, then we successfully
+      // created this one so return its path. otherwise, we reject with the
+      // original error by ignoring the error in the catch
+      try {
+        const stat = await fs.stat(dir)
+        if (stat.isDirectory()) {
+          // if it already existed, we didn't create anything so return
+          // undefined
+          return undefined
+        }
+      } catch (_) {}
+
+      // if the thing that's there isn't a directory, then just re-throw
+      throw err
+    }
+  }
+
+  return makeDirectory(path, options.mode)
+}
+
+module.exports = mkdir
diff --git a/server/node_modules/@npmcli/fs/lib/mkdtemp.js b/server/node_modules/@npmcli/fs/lib/mkdtemp.js
new file mode 100644
index 0000000..b7f0780
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/mkdtemp.js
@@ -0,0 +1,28 @@
+const { dirname, sep } = require('path')
+
+const fs = require('./fs.js')
+const getOptions = require('./common/get-options.js')
+const owner = require('./common/owner.js')
+
+const mkdtemp = async (prefix, opts) => {
+  const options = getOptions(opts, {
+    copy: ['encoding', 'owner'],
+    wrap: 'encoding',
+  })
+
+  // mkdtemp relies on the trailing path separator to indicate if it should
+  // create a directory inside of the prefix. if that's the case then the root
+  // we infer ownership from is the prefix itself, otherwise it's the dirname
+  // /tmp -> /tmpABCDEF, infers from /
+  // /tmp/ -> /tmp/ABCDEF, infers from /tmp
+  const root = prefix.endsWith(sep) ? prefix : dirname(prefix)
+  const { uid, gid } = await owner.validate(root, options.owner)
+
+  const result = await fs.mkdtemp(prefix, options)
+
+  await owner.update(result, uid, gid)
+
+  return result
+}
+
+module.exports = mkdtemp
diff --git a/server/node_modules/@npmcli/fs/lib/rm/index.js b/server/node_modules/@npmcli/fs/lib/rm/index.js
new file mode 100644
index 0000000..cb81fbd
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/rm/index.js
@@ -0,0 +1,22 @@
+const fs = require('../fs.js')
+const getOptions = require('../common/get-options.js')
+const node = require('../common/node.js')
+const polyfill = require('./polyfill.js')
+
+// node 14.14.0 added fs.rm, which allows both the force and recursive options
+const useNative = node.satisfies('>=14.14.0')
+
+const rm = async (path, opts) => {
+  const options = getOptions(opts, {
+    copy: ['retryDelay', 'maxRetries', 'recursive', 'force'],
+  })
+
+  // the polyfill is tested separately from this module, no need to hack
+  // process.version to try to trigger it just for coverage
+  // istanbul ignore next
+  return useNative
+    ? fs.rm(path, options)
+    : polyfill(path, options)
+}
+
+module.exports = rm
diff --git a/server/node_modules/@npmcli/fs/lib/rm/polyfill.js b/server/node_modules/@npmcli/fs/lib/rm/polyfill.js
new file mode 100644
index 0000000..a25c174
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/rm/polyfill.js
@@ -0,0 +1,239 @@
+// this file is a modified version of the code in node core >=14.14.0
+// which is, in turn, a modified version of the rimraf module on npm
+// node core changes:
+// - Use of the assert module has been replaced with core's error system.
+// - All code related to the glob dependency has been removed.
+// - Bring your own custom fs module is not currently supported.
+// - Some basic code cleanup.
+// changes here:
+// - remove all callback related code
+// - drop sync support
+// - change assertions back to non-internal methods (see options.js)
+// - throws ENOTDIR when rmdir gets an ENOENT for a path that exists in Windows
+const errnos = require('os').constants.errno
+const { join } = require('path')
+const fs = require('../fs.js')
+
+// error codes that mean we need to remove contents
+const notEmptyCodes = new Set([
+  'ENOTEMPTY',
+  'EEXIST',
+  'EPERM',
+])
+
+// error codes we can retry later
+const retryCodes = new Set([
+  'EBUSY',
+  'EMFILE',
+  'ENFILE',
+  'ENOTEMPTY',
+  'EPERM',
+])
+
+const isWindows = process.platform === 'win32'
+
+const defaultOptions = {
+  retryDelay: 100,
+  maxRetries: 0,
+  recursive: false,
+  force: false,
+}
+
+// this is drastically simplified, but should be roughly equivalent to what
+// node core throws
+class ERR_FS_EISDIR extends Error {
+  constructor (path) {
+    super()
+    this.info = {
+      code: 'EISDIR',
+      message: 'is a directory',
+      path,
+      syscall: 'rm',
+      errno: errnos.EISDIR,
+    }
+    this.name = 'SystemError'
+    this.code = 'ERR_FS_EISDIR'
+    this.errno = errnos.EISDIR
+    this.syscall = 'rm'
+    this.path = path
+    this.message = `Path is a directory: ${this.syscall} returned ` +
+      `${this.info.code} (is a directory) ${path}`
+  }
+
+  toString () {
+    return `${this.name} [${this.code}]: ${this.message}`
+  }
+}
+
+class ENOTDIR extends Error {
+  constructor (path) {
+    super()
+    this.name = 'Error'
+    this.code = 'ENOTDIR'
+    this.errno = errnos.ENOTDIR
+    this.syscall = 'rmdir'
+    this.path = path
+    this.message = `not a directory, ${this.syscall} '${this.path}'`
+  }
+
+  toString () {
+    return `${this.name}: ${this.code}: ${this.message}`
+  }
+}
+
+// force is passed separately here because we respect it for the first entry
+// into rimraf only, any further calls that are spawned as a result (i.e. to
+// delete content within the target) will ignore ENOENT errors
+const rimraf = async (path, options, isTop = false) => {
+  const force = isTop ? options.force : true
+  const stat = await fs.lstat(path)
+    .catch((err) => {
+      // we only ignore ENOENT if we're forcing this call
+      if (err.code === 'ENOENT' && force) {
+        return
+      }
+
+      if (isWindows && err.code === 'EPERM') {
+        return fixEPERM(path, options, err, isTop)
+      }
+
+      throw err
+    })
+
+  // no stat object here means either lstat threw an ENOENT, or lstat threw
+  // an EPERM and the fixPERM function took care of things. either way, we're
+  // already done, so return early
+  if (!stat) {
+    return
+  }
+
+  if (stat.isDirectory()) {
+    return rmdir(path, options, null, isTop)
+  }
+
+  return fs.unlink(path)
+    .catch((err) => {
+      if (err.code === 'ENOENT' && force) {
+        return
+      }
+
+      if (err.code === 'EISDIR') {
+        return rmdir(path, options, err, isTop)
+      }
+
+      if (err.code === 'EPERM') {
+        // in windows, we handle this through fixEPERM which will also try to
+        // delete things again. everywhere else since deleting the target as a
+        // file didn't work we go ahead and try to delete it as a directory
+        return isWindows
+          ? fixEPERM(path, options, err, isTop)
+          : rmdir(path, options, err, isTop)
+      }
+
+      throw err
+    })
+}
+
+const fixEPERM = async (path, options, originalErr, isTop) => {
+  const force = isTop ? options.force : true
+  const targetMissing = await fs.chmod(path, 0o666)
+    .catch((err) => {
+      if (err.code === 'ENOENT' && force) {
+        return true
+      }
+
+      throw originalErr
+    })
+
+  // got an ENOENT above, return now. no file = no problem
+  if (targetMissing) {
+    return
+  }
+
+  // this function does its own lstat rather than calling rimraf again to avoid
+  // infinite recursion for a repeating EPERM
+  const stat = await fs.lstat(path)
+    .catch((err) => {
+      if (err.code === 'ENOENT' && force) {
+        return
+      }
+
+      throw originalErr
+    })
+
+  if (!stat) {
+    return
+  }
+
+  if (stat.isDirectory()) {
+    return rmdir(path, options, originalErr, isTop)
+  }
+
+  return fs.unlink(path)
+}
+
+const rmdir = async (path, options, originalErr, isTop) => {
+  if (!options.recursive && isTop) {
+    throw originalErr || new ERR_FS_EISDIR(path)
+  }
+  const force = isTop ? options.force : true
+
+  return fs.rmdir(path)
+    .catch(async (err) => {
+      // in Windows, calling rmdir on a file path will fail with ENOENT rather
+      // than ENOTDIR. to determine if that's what happened, we have to do
+      // another lstat on the path. if the path isn't actually gone, we throw
+      // away the ENOENT and replace it with our own ENOTDIR
+      if (isWindows && err.code === 'ENOENT') {
+        const stillExists = await fs.lstat(path).then(() => true, () => false)
+        if (stillExists) {
+          err = new ENOTDIR(path)
+        }
+      }
+
+      // not there, not a problem
+      if (err.code === 'ENOENT' && force) {
+        return
+      }
+
+      // we may not have originalErr if lstat tells us our target is a
+      // directory but that changes before we actually remove it, so
+      // only throw it here if it's set
+      if (originalErr && err.code === 'ENOTDIR') {
+        throw originalErr
+      }
+
+      // the directory isn't empty, remove the contents and try again
+      if (notEmptyCodes.has(err.code)) {
+        const files = await fs.readdir(path)
+        await Promise.all(files.map((file) => {
+          const target = join(path, file)
+          return rimraf(target, options)
+        }))
+        return fs.rmdir(path)
+      }
+
+      throw err
+    })
+}
+
+const rm = async (path, opts) => {
+  const options = { ...defaultOptions, ...opts }
+  let retries = 0
+
+  const errHandler = async (err) => {
+    if (retryCodes.has(err.code) && ++retries < options.maxRetries) {
+      const delay = retries * options.retryDelay
+      await promiseTimeout(delay)
+      return rimraf(path, options, true).catch(errHandler)
+    }
+
+    throw err
+  }
+
+  return rimraf(path, options, true).catch(errHandler)
+}
+
+const promiseTimeout = (ms) => new Promise((r) => setTimeout(r, ms))
+
+module.exports = rm
diff --git a/server/node_modules/@npmcli/fs/lib/with-temp-dir.js b/server/node_modules/@npmcli/fs/lib/with-temp-dir.js
new file mode 100644
index 0000000..353d555
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/with-temp-dir.js
@@ -0,0 +1,39 @@
+const { join, sep } = require('path')
+
+const getOptions = require('./common/get-options.js')
+const mkdir = require('./mkdir/index.js')
+const mkdtemp = require('./mkdtemp.js')
+const rm = require('./rm/index.js')
+
+// create a temp directory, ensure its permissions match its parent, then call
+// the supplied function passing it the path to the directory. clean up after
+// the function finishes, whether it throws or not
+const withTempDir = async (root, fn, opts) => {
+  const options = getOptions(opts, {
+    copy: ['tmpPrefix'],
+  })
+  // create the directory, and fix its ownership
+  await mkdir(root, { recursive: true, owner: 'inherit' })
+
+  const target = await mkdtemp(join(`${root}${sep}`, options.tmpPrefix || ''), { owner: 'inherit' })
+  let err
+  let result
+
+  try {
+    result = await fn(target)
+  } catch (_err) {
+    err = _err
+  }
+
+  try {
+    await rm(target, { force: true, recursive: true })
+  } catch (err) {}
+
+  if (err) {
+    throw err
+  }
+
+  return result
+}
+
+module.exports = withTempDir
diff --git a/server/node_modules/@npmcli/fs/lib/write-file.js b/server/node_modules/@npmcli/fs/lib/write-file.js
new file mode 100644
index 0000000..01de531
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/lib/write-file.js
@@ -0,0 +1,19 @@
+const fs = require('./fs.js')
+const getOptions = require('./common/get-options.js')
+const owner = require('./common/owner.js')
+
+const writeFile = async (file, data, opts) => {
+  const options = getOptions(opts, {
+    copy: ['encoding', 'mode', 'flag', 'signal', 'owner'],
+    wrap: 'encoding',
+  })
+  const { uid, gid } = await owner.validate(file, options.owner)
+
+  const result = await fs.writeFile(file, data, options)
+
+  await owner.update(file, uid, gid)
+
+  return result
+}
+
+module.exports = writeFile
diff --git a/server/node_modules/@npmcli/fs/package.json b/server/node_modules/@npmcli/fs/package.json
new file mode 100644
index 0000000..0296aa7
--- /dev/null
+++ b/server/node_modules/@npmcli/fs/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "@npmcli/fs",
+  "version": "1.1.1",
+  "description": "filesystem utilities for the npm cli",
+  "main": "lib/index.js",
+  "files": [
+    "bin",
+    "lib"
+  ],
+  "scripts": {
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags",
+    "snap": "tap",
+    "test": "tap",
+    "npmclilint": "npmcli-lint",
+    "lint": "eslint '**/*.js'",
+    "lintfix": "npm run lint -- --fix",
+    "posttest": "npm run lint",
+    "postsnap": "npm run lintfix --",
+    "postlint": "npm-template-check"
+  },
+  "keywords": [
+    "npm",
+    "oss"
+  ],
+  "author": "GitHub Inc.",
+  "license": "ISC",
+  "devDependencies": {
+    "@npmcli/template-oss": "^2.3.1",
+    "tap": "^15.0.9"
+  },
+  "dependencies": {
+    "@gar/promisify": "^1.0.1",
+    "semver": "^7.3.5"
+  },
+  "templateVersion": "2.3.1"
+}
diff --git a/server/node_modules/@npmcli/move-file/LICENSE.md b/server/node_modules/@npmcli/move-file/LICENSE.md
new file mode 100644
index 0000000..072bf20
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/LICENSE.md
@@ -0,0 +1,22 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com)
+Copyright (c) npm, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/@npmcli/move-file/README.md b/server/node_modules/@npmcli/move-file/README.md
new file mode 100644
index 0000000..8a5a57f
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/README.md
@@ -0,0 +1,69 @@
+# @npmcli/move-file
+
+A fork of [move-file](https://github.com/sindresorhus/move-file) with
+compatibility with all node 10.x versions.
+
+> Move a file (or directory)
+
+The built-in
+[`fs.rename()`](https://nodejs.org/api/fs.html#fs_fs_rename_oldpath_newpath_callback)
+is just a JavaScript wrapper for the C `rename(2)` function, which doesn't
+support moving files across partitions or devices. This module is what you
+would have expected `fs.rename()` to be.
+
+## Highlights
+
+- Promise API.
+- Supports moving a file across partitions and devices.
+- Optionally prevent overwriting an existing file.
+- Creates non-existent destination directories for you.
+- Support for Node versions that lack built-in recursive `fs.mkdir()`
+- Automatically recurses when source is a directory.
+
+## Install
+
+```
+$ npm install @npmcli/move-file
+```
+
+## Usage
+
+```js
+const moveFile = require('@npmcli/move-file');
+
+(async () => {
+	await moveFile('source/unicorn.png', 'destination/unicorn.png');
+	console.log('The file has been moved');
+})();
+```
+
+## API
+
+### moveFile(source, destination, options?)
+
+Returns a `Promise` that resolves when the file has been moved.
+
+### moveFile.sync(source, destination, options?)
+
+#### source
+
+Type: `string`
+
+File, or directory, you want to move.
+
+#### destination
+
+Type: `string`
+
+Where you want the file or directory moved.
+
+#### options
+
+Type: `object`
+
+##### overwrite
+
+Type: `boolean`\
+Default: `true`
+
+Overwrite existing destination file(s).
diff --git a/server/node_modules/@npmcli/move-file/index.js b/server/node_modules/@npmcli/move-file/index.js
new file mode 100644
index 0000000..95d1888
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/index.js
@@ -0,0 +1,162 @@
+const { dirname, join, resolve, relative, isAbsolute } = require('path')
+const rimraf_ = require('rimraf')
+const { promisify } = require('util')
+const {
+  access: access_,
+  accessSync,
+  copyFile: copyFile_,
+  copyFileSync,
+  unlink: unlink_,
+  unlinkSync,
+  readdir: readdir_,
+  readdirSync,
+  rename: rename_,
+  renameSync,
+  stat: stat_,
+  statSync,
+  lstat: lstat_,
+  lstatSync,
+  symlink: symlink_,
+  symlinkSync,
+  readlink: readlink_,
+  readlinkSync
+} = require('fs')
+
+const access = promisify(access_)
+const copyFile = promisify(copyFile_)
+const unlink = promisify(unlink_)
+const readdir = promisify(readdir_)
+const rename = promisify(rename_)
+const stat = promisify(stat_)
+const lstat = promisify(lstat_)
+const symlink = promisify(symlink_)
+const readlink = promisify(readlink_)
+const rimraf = promisify(rimraf_)
+const rimrafSync = rimraf_.sync
+
+const mkdirp = require('mkdirp')
+
+const pathExists = async path => {
+  try {
+    await access(path)
+    return true
+  } catch (er) {
+    return er.code !== 'ENOENT'
+  }
+}
+
+const pathExistsSync = path => {
+  try {
+    accessSync(path)
+    return true
+  } catch (er) {
+    return er.code !== 'ENOENT'
+  }
+}
+
+const moveFile = async (source, destination, options = {}, root = true, symlinks = []) => {
+  if (!source || !destination) {
+    throw new TypeError('`source` and `destination` file required')
+  }
+
+  options = {
+    overwrite: true,
+    ...options
+  }
+
+  if (!options.overwrite && await pathExists(destination)) {
+    throw new Error(`The destination file exists: ${destination}`)
+  }
+
+  await mkdirp(dirname(destination))
+
+  try {
+    await rename(source, destination)
+  } catch (error) {
+    if (error.code === 'EXDEV' || error.code === 'EPERM') {
+      const sourceStat = await lstat(source)
+      if (sourceStat.isDirectory()) {
+        const files = await readdir(source)
+        await Promise.all(files.map((file) => moveFile(join(source, file), join(destination, file), options, false, symlinks)))
+      } else if (sourceStat.isSymbolicLink()) {
+        symlinks.push({ source, destination })
+      } else {
+        await copyFile(source, destination)
+      }
+    } else {
+      throw error
+    }
+  }
+
+  if (root) {
+    await Promise.all(symlinks.map(async ({ source, destination }) => {
+      let target = await readlink(source)
+      // junction symlinks in windows will be absolute paths, so we need to make sure they point to the destination
+      if (isAbsolute(target))
+        target = resolve(destination, relative(source, target))
+      // try to determine what the actual file is so we can create the correct type of symlink in windows
+      let targetStat
+      try {
+        targetStat = await stat(resolve(dirname(source), target))
+      } catch (err) {}
+      await symlink(target, destination, targetStat && targetStat.isDirectory() ? 'junction' : 'file')
+    }))
+    await rimraf(source)
+  }
+}
+
+const moveFileSync = (source, destination, options = {}, root = true, symlinks = []) => {
+  if (!source || !destination) {
+    throw new TypeError('`source` and `destination` file required')
+  }
+
+  options = {
+    overwrite: true,
+    ...options
+  }
+
+  if (!options.overwrite && pathExistsSync(destination)) {
+    throw new Error(`The destination file exists: ${destination}`)
+  }
+
+  mkdirp.sync(dirname(destination))
+
+  try {
+    renameSync(source, destination)
+  } catch (error) {
+    if (error.code === 'EXDEV' || error.code === 'EPERM') {
+      const sourceStat = lstatSync(source)
+      if (sourceStat.isDirectory()) {
+        const files = readdirSync(source)
+        for (const file of files) {
+          moveFileSync(join(source, file), join(destination, file), options, false, symlinks)
+        }
+      } else if (sourceStat.isSymbolicLink()) {
+        symlinks.push({ source, destination })
+      } else {
+        copyFileSync(source, destination)
+      }
+    } else {
+      throw error
+    }
+  }
+
+  if (root) {
+    for (const { source, destination } of symlinks) {
+      let target = readlinkSync(source)
+      // junction symlinks in windows will be absolute paths, so we need to make sure they point to the destination
+      if (isAbsolute(target))
+        target = resolve(destination, relative(source, target))
+      // try to determine what the actual file is so we can create the correct type of symlink in windows
+      let targetStat
+      try {
+        targetStat = statSync(resolve(dirname(source), target))
+      } catch (err) {}
+      symlinkSync(target, destination, targetStat && targetStat.isDirectory() ? 'junction' : 'file')
+    }
+    rimrafSync(source)
+  }
+}
+
+module.exports = moveFile
+module.exports.sync = moveFileSync
diff --git a/server/node_modules/@npmcli/move-file/node_modules/.bin/mkdirp b/server/node_modules/@npmcli/move-file/node_modules/.bin/mkdirp
new file mode 120000
index 0000000..017896c
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/.bin/mkdirp
@@ -0,0 +1 @@
+../mkdirp/bin/cmd.js
\ No newline at end of file
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/CHANGELOG.md b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/CHANGELOG.md
new file mode 100644
index 0000000..8145838
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/CHANGELOG.md
@@ -0,0 +1,15 @@
+# Changers Lorgs!
+
+## 1.0
+
+Full rewrite.  Essentially a brand new module.
+
+- Return a promise instead of taking a callback.
+- Use native `fs.mkdir(path, { recursive: true })` when available.
+- Drop support for outdated Node.js versions.  (Technically still works on
+  Node.js v8, but only 10 and above are officially supported.)
+
+## 0.x
+
+Original and most widely used recursive directory creation implementation
+in JavaScript, dating back to 2010.
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/LICENSE b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/LICENSE
new file mode 100644
index 0000000..13fcd15
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/LICENSE
@@ -0,0 +1,21 @@
+Copyright James Halliday (mail@substack.net) and Isaac Z. Schlueter (i@izs.me)
+
+This project is free software released under the MIT license:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/bin/cmd.js b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/bin/cmd.js
new file mode 100755
index 0000000..6e0aa8d
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/bin/cmd.js
@@ -0,0 +1,68 @@
+#!/usr/bin/env node
+
+const usage = () => `
+usage: mkdirp [DIR1,DIR2..] {OPTIONS}
+
+  Create each supplied directory including any necessary parent directories
+  that don't yet exist.
+
+  If the directory already exists, do nothing.
+
+OPTIONS are:
+
+  -m<mode>       If a directory needs to be created, set the mode as an octal
+  --mode=<mode>  permission string.
+
+  -v --version   Print the mkdirp version number
+
+  -h --help      Print this helpful banner
+
+  -p --print     Print the first directories created for each path provided
+
+  --manual       Use manual implementation, even if native is available
+`
+
+const dirs = []
+const opts = {}
+let print = false
+let dashdash = false
+let manual = false
+for (const arg of process.argv.slice(2)) {
+  if (dashdash)
+    dirs.push(arg)
+  else if (arg === '--')
+    dashdash = true
+  else if (arg === '--manual')
+    manual = true
+  else if (/^-h/.test(arg) || /^--help/.test(arg)) {
+    console.log(usage())
+    process.exit(0)
+  } else if (arg === '-v' || arg === '--version') {
+    console.log(require('../package.json').version)
+    process.exit(0)
+  } else if (arg === '-p' || arg === '--print') {
+    print = true
+  } else if (/^-m/.test(arg) || /^--mode=/.test(arg)) {
+    const mode = parseInt(arg.replace(/^(-m|--mode=)/, ''), 8)
+    if (isNaN(mode)) {
+      console.error(`invalid mode argument: ${arg}\nMust be an octal number.`)
+      process.exit(1)
+    }
+    opts.mode = mode
+  } else
+    dirs.push(arg)
+}
+
+const mkdirp = require('../')
+const impl = manual ? mkdirp.manual : mkdirp
+if (dirs.length === 0)
+  console.error(usage())
+
+Promise.all(dirs.map(dir => impl(dir, opts)))
+  .then(made => print ? made.forEach(m => m && console.log(m)) : null)
+  .catch(er => {
+    console.error(er.message)
+    if (er.code)
+      console.error('  code: ' + er.code)
+    process.exit(1)
+  })
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/index.js b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/index.js
new file mode 100644
index 0000000..ad7a16c
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/index.js
@@ -0,0 +1,31 @@
+const optsArg = require('./lib/opts-arg.js')
+const pathArg = require('./lib/path-arg.js')
+
+const {mkdirpNative, mkdirpNativeSync} = require('./lib/mkdirp-native.js')
+const {mkdirpManual, mkdirpManualSync} = require('./lib/mkdirp-manual.js')
+const {useNative, useNativeSync} = require('./lib/use-native.js')
+
+
+const mkdirp = (path, opts) => {
+  path = pathArg(path)
+  opts = optsArg(opts)
+  return useNative(opts)
+    ? mkdirpNative(path, opts)
+    : mkdirpManual(path, opts)
+}
+
+const mkdirpSync = (path, opts) => {
+  path = pathArg(path)
+  opts = optsArg(opts)
+  return useNativeSync(opts)
+    ? mkdirpNativeSync(path, opts)
+    : mkdirpManualSync(path, opts)
+}
+
+mkdirp.sync = mkdirpSync
+mkdirp.native = (path, opts) => mkdirpNative(pathArg(path), optsArg(opts))
+mkdirp.manual = (path, opts) => mkdirpManual(pathArg(path), optsArg(opts))
+mkdirp.nativeSync = (path, opts) => mkdirpNativeSync(pathArg(path), optsArg(opts))
+mkdirp.manualSync = (path, opts) => mkdirpManualSync(pathArg(path), optsArg(opts))
+
+module.exports = mkdirp
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/find-made.js b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/find-made.js
new file mode 100644
index 0000000..022e492
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/find-made.js
@@ -0,0 +1,29 @@
+const {dirname} = require('path')
+
+const findMade = (opts, parent, path = undefined) => {
+  // we never want the 'made' return value to be a root directory
+  if (path === parent)
+    return Promise.resolve()
+
+  return opts.statAsync(parent).then(
+    st => st.isDirectory() ? path : undefined, // will fail later
+    er => er.code === 'ENOENT'
+      ? findMade(opts, dirname(parent), parent)
+      : undefined
+  )
+}
+
+const findMadeSync = (opts, parent, path = undefined) => {
+  if (path === parent)
+    return undefined
+
+  try {
+    return opts.statSync(parent).isDirectory() ? path : undefined
+  } catch (er) {
+    return er.code === 'ENOENT'
+      ? findMadeSync(opts, dirname(parent), parent)
+      : undefined
+  }
+}
+
+module.exports = {findMade, findMadeSync}
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/mkdirp-manual.js b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/mkdirp-manual.js
new file mode 100644
index 0000000..2eb18cd
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/mkdirp-manual.js
@@ -0,0 +1,64 @@
+const {dirname} = require('path')
+
+const mkdirpManual = (path, opts, made) => {
+  opts.recursive = false
+  const parent = dirname(path)
+  if (parent === path) {
+    return opts.mkdirAsync(path, opts).catch(er => {
+      // swallowed by recursive implementation on posix systems
+      // any other error is a failure
+      if (er.code !== 'EISDIR')
+        throw er
+    })
+  }
+
+  return opts.mkdirAsync(path, opts).then(() => made || path, er => {
+    if (er.code === 'ENOENT')
+      return mkdirpManual(parent, opts)
+        .then(made => mkdirpManual(path, opts, made))
+    if (er.code !== 'EEXIST' && er.code !== 'EROFS')
+      throw er
+    return opts.statAsync(path).then(st => {
+      if (st.isDirectory())
+        return made
+      else
+        throw er
+    }, () => { throw er })
+  })
+}
+
+const mkdirpManualSync = (path, opts, made) => {
+  const parent = dirname(path)
+  opts.recursive = false
+
+  if (parent === path) {
+    try {
+      return opts.mkdirSync(path, opts)
+    } catch (er) {
+      // swallowed by recursive implementation on posix systems
+      // any other error is a failure
+      if (er.code !== 'EISDIR')
+        throw er
+      else
+        return
+    }
+  }
+
+  try {
+    opts.mkdirSync(path, opts)
+    return made || path
+  } catch (er) {
+    if (er.code === 'ENOENT')
+      return mkdirpManualSync(path, opts, mkdirpManualSync(parent, opts, made))
+    if (er.code !== 'EEXIST' && er.code !== 'EROFS')
+      throw er
+    try {
+      if (!opts.statSync(path).isDirectory())
+        throw er
+    } catch (_) {
+      throw er
+    }
+  }
+}
+
+module.exports = {mkdirpManual, mkdirpManualSync}
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/mkdirp-native.js b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/mkdirp-native.js
new file mode 100644
index 0000000..c7a6b69
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/mkdirp-native.js
@@ -0,0 +1,39 @@
+const {dirname} = require('path')
+const {findMade, findMadeSync} = require('./find-made.js')
+const {mkdirpManual, mkdirpManualSync} = require('./mkdirp-manual.js')
+
+const mkdirpNative = (path, opts) => {
+  opts.recursive = true
+  const parent = dirname(path)
+  if (parent === path)
+    return opts.mkdirAsync(path, opts)
+
+  return findMade(opts, path).then(made =>
+    opts.mkdirAsync(path, opts).then(() => made)
+    .catch(er => {
+      if (er.code === 'ENOENT')
+        return mkdirpManual(path, opts)
+      else
+        throw er
+    }))
+}
+
+const mkdirpNativeSync = (path, opts) => {
+  opts.recursive = true
+  const parent = dirname(path)
+  if (parent === path)
+    return opts.mkdirSync(path, opts)
+
+  const made = findMadeSync(opts, path)
+  try {
+    opts.mkdirSync(path, opts)
+    return made
+  } catch (er) {
+    if (er.code === 'ENOENT')
+      return mkdirpManualSync(path, opts)
+    else
+      throw er
+  }
+}
+
+module.exports = {mkdirpNative, mkdirpNativeSync}
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/opts-arg.js b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/opts-arg.js
new file mode 100644
index 0000000..2fa4833
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/opts-arg.js
@@ -0,0 +1,23 @@
+const { promisify } = require('util')
+const fs = require('fs')
+const optsArg = opts => {
+  if (!opts)
+    opts = { mode: 0o777, fs }
+  else if (typeof opts === 'object')
+    opts = { mode: 0o777, fs, ...opts }
+  else if (typeof opts === 'number')
+    opts = { mode: opts, fs }
+  else if (typeof opts === 'string')
+    opts = { mode: parseInt(opts, 8), fs }
+  else
+    throw new TypeError('invalid options argument')
+
+  opts.mkdir = opts.mkdir || opts.fs.mkdir || fs.mkdir
+  opts.mkdirAsync = promisify(opts.mkdir)
+  opts.stat = opts.stat || opts.fs.stat || fs.stat
+  opts.statAsync = promisify(opts.stat)
+  opts.statSync = opts.statSync || opts.fs.statSync || fs.statSync
+  opts.mkdirSync = opts.mkdirSync || opts.fs.mkdirSync || fs.mkdirSync
+  return opts
+}
+module.exports = optsArg
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/path-arg.js b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/path-arg.js
new file mode 100644
index 0000000..cc07de5
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/path-arg.js
@@ -0,0 +1,29 @@
+const platform = process.env.__TESTING_MKDIRP_PLATFORM__ || process.platform
+const { resolve, parse } = require('path')
+const pathArg = path => {
+  if (/\0/.test(path)) {
+    // simulate same failure that node raises
+    throw Object.assign(
+      new TypeError('path must be a string without null bytes'),
+      {
+        path,
+        code: 'ERR_INVALID_ARG_VALUE',
+      }
+    )
+  }
+
+  path = resolve(path)
+  if (platform === 'win32') {
+    const badWinChars = /[*|"<>?:]/
+    const {root} = parse(path)
+    if (badWinChars.test(path.substr(root.length))) {
+      throw Object.assign(new Error('Illegal characters in path.'), {
+        path,
+        code: 'EINVAL',
+      })
+    }
+  }
+
+  return path
+}
+module.exports = pathArg
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/use-native.js b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/use-native.js
new file mode 100644
index 0000000..079361d
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/lib/use-native.js
@@ -0,0 +1,10 @@
+const fs = require('fs')
+
+const version = process.env.__TESTING_MKDIRP_NODE_VERSION__ || process.version
+const versArr = version.replace(/^v/, '').split('.')
+const hasNative = +versArr[0] > 10 || +versArr[0] === 10 && +versArr[1] >= 12
+
+const useNative = !hasNative ? () => false : opts => opts.mkdir === fs.mkdir
+const useNativeSync = !hasNative ? () => false : opts => opts.mkdirSync === fs.mkdirSync
+
+module.exports = {useNative, useNativeSync}
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/package.json b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/package.json
new file mode 100644
index 0000000..2913ed0
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "mkdirp",
+  "description": "Recursively mkdir, like `mkdir -p`",
+  "version": "1.0.4",
+  "main": "index.js",
+  "keywords": [
+    "mkdir",
+    "directory",
+    "make dir",
+    "make",
+    "dir",
+    "recursive",
+    "native"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/isaacs/node-mkdirp.git"
+  },
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "tap": {
+    "check-coverage": true,
+    "coverage-map": "map.js"
+  },
+  "devDependencies": {
+    "require-inject": "^1.4.4",
+    "tap": "^14.10.7"
+  },
+  "bin": "bin/cmd.js",
+  "license": "MIT",
+  "engines": {
+    "node": ">=10"
+  },
+  "files": [
+    "bin",
+    "lib",
+    "index.js"
+  ]
+}
diff --git a/server/node_modules/@npmcli/move-file/node_modules/mkdirp/readme.markdown b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/readme.markdown
new file mode 100644
index 0000000..827de59
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/node_modules/mkdirp/readme.markdown
@@ -0,0 +1,266 @@
+# mkdirp
+
+Like `mkdir -p`, but in Node.js!
+
+Now with a modern API and no\* bugs!
+
+<small>\* may contain some bugs</small>
+
+# example
+
+## pow.js
+
+```js
+const mkdirp = require('mkdirp')
+
+// return value is a Promise resolving to the first directory created
+mkdirp('/tmp/foo/bar/baz').then(made =>
+  console.log(`made directories, starting with ${made}`))
+```
+
+Output (where `/tmp/foo` already exists)
+
+```
+made directories, starting with /tmp/foo/bar
+```
+
+Or, if you don't have time to wait around for promises:
+
+```js
+const mkdirp = require('mkdirp')
+
+// return value is the first directory created
+const made = mkdirp.sync('/tmp/foo/bar/baz')
+console.log(`made directories, starting with ${made}`)
+```
+
+And now /tmp/foo/bar/baz exists, huzzah!
+
+# methods
+
+```js
+const mkdirp = require('mkdirp')
+```
+
+## mkdirp(dir, [opts]) -> Promise<String | undefined>
+
+Create a new directory and any necessary subdirectories at `dir` with octal
+permission string `opts.mode`. If `opts` is a string or number, it will be
+treated as the `opts.mode`.
+
+If `opts.mode` isn't specified, it defaults to `0o777 &
+(~process.umask())`.
+
+Promise resolves to first directory `made` that had to be created, or
+`undefined` if everything already exists.  Promise rejects if any errors
+are encountered.  Note that, in the case of promise rejection, some
+directories _may_ have been created, as recursive directory creation is not
+an atomic operation.
+
+You can optionally pass in an alternate `fs` implementation by passing in
+`opts.fs`. Your implementation should have `opts.fs.mkdir(path, opts, cb)`
+and `opts.fs.stat(path, cb)`.
+
+You can also override just one or the other of `mkdir` and `stat` by
+passing in `opts.stat` or `opts.mkdir`, or providing an `fs` option that
+only overrides one of these.
+
+## mkdirp.sync(dir, opts) -> String|null
+
+Synchronously create a new directory and any necessary subdirectories at
+`dir` with octal permission string `opts.mode`. If `opts` is a string or
+number, it will be treated as the `opts.mode`.
+
+If `opts.mode` isn't specified, it defaults to `0o777 &
+(~process.umask())`.
+
+Returns the first directory that had to be created, or undefined if
+everything already exists.
+
+You can optionally pass in an alternate `fs` implementation by passing in
+`opts.fs`. Your implementation should have `opts.fs.mkdirSync(path, mode)`
+and `opts.fs.statSync(path)`.
+
+You can also override just one or the other of `mkdirSync` and `statSync`
+by passing in `opts.statSync` or `opts.mkdirSync`, or providing an `fs`
+option that only overrides one of these.
+
+## mkdirp.manual, mkdirp.manualSync
+
+Use the manual implementation (not the native one).  This is the default
+when the native implementation is not available or the stat/mkdir
+implementation is overridden.
+
+## mkdirp.native, mkdirp.nativeSync
+
+Use the native implementation (not the manual one).  This is the default
+when the native implementation is available and stat/mkdir are not
+overridden.
+
+# implementation
+
+On Node.js v10.12.0 and above, use the native `fs.mkdir(p,
+{recursive:true})` option, unless `fs.mkdir`/`fs.mkdirSync` has been
+overridden by an option.
+
+## native implementation
+
+- If the path is a root directory, then pass it to the underlying
+  implementation and return the result/error.  (In this case, it'll either
+  succeed or fail, but we aren't actually creating any dirs.)
+- Walk up the path statting each directory, to find the first path that
+  will be created, `made`.
+- Call `fs.mkdir(path, { recursive: true })` (or `fs.mkdirSync`)
+- If error, raise it to the caller.
+- Return `made`.
+
+## manual implementation
+
+- Call underlying `fs.mkdir` implementation, with `recursive: false`
+- If error:
+  - If path is a root directory, raise to the caller and do not handle it
+  - If ENOENT, mkdirp parent dir, store result as `made`
+  - stat(path)
+    - If error, raise original `mkdir` error
+    - If directory, return `made`
+    - Else, raise original `mkdir` error
+- else
+  - return `undefined` if a root dir, or `made` if set, or `path`
+
+## windows vs unix caveat
+
+On Windows file systems, attempts to create a root directory (ie, a drive
+letter or root UNC path) will fail.  If the root directory exists, then it
+will fail with `EPERM`.  If the root directory does not exist, then it will
+fail with `ENOENT`.
+
+On posix file systems, attempts to create a root directory (in recursive
+mode) will succeed silently, as it is treated like just another directory
+that already exists.  (In non-recursive mode, of course, it fails with
+`EEXIST`.)
+
+In order to preserve this system-specific behavior (and because it's not as
+if we can create the parent of a root directory anyway), attempts to create
+a root directory are passed directly to the `fs` implementation, and any
+errors encountered are not handled.
+
+## native error caveat
+
+The native implementation (as of at least Node.js v13.4.0) does not provide
+appropriate errors in some cases (see
+[nodejs/node#31481](https://github.com/nodejs/node/issues/31481) and
+[nodejs/node#28015](https://github.com/nodejs/node/issues/28015)).
+
+In order to work around this issue, the native implementation will fall
+back to the manual implementation if an `ENOENT` error is encountered.
+
+# choosing a recursive mkdir implementation
+
+There are a few to choose from!  Use the one that suits your needs best :D
+
+## use `fs.mkdir(path, {recursive: true}, cb)` if:
+
+- You wish to optimize performance even at the expense of other factors.
+- You don't need to know the first dir created.
+- You are ok with getting `ENOENT` as the error when some other problem is
+  the actual cause.
+- You can limit your platforms to Node.js v10.12 and above.
+- You're ok with using callbacks instead of promises.
+- You don't need/want a CLI.
+- You don't need to override the `fs` methods in use.
+
+## use this module (mkdirp 1.x) if:
+
+- You need to know the first directory that was created.
+- You wish to use the native implementation if available, but fall back
+  when it's not.
+- You prefer promise-returning APIs to callback-taking APIs.
+- You want more useful error messages than the native recursive mkdir
+  provides (at least as of Node.js v13.4), and are ok with re-trying on
+  `ENOENT` to achieve this.
+- You need (or at least, are ok with) a CLI.
+- You need to override the `fs` methods in use.
+
+## use [`make-dir`](http://npm.im/make-dir) if:
+
+- You do not need to know the first dir created (and wish to save a few
+  `stat` calls when using the native implementation for this reason).
+- You wish to use the native implementation if available, but fall back
+  when it's not.
+- You prefer promise-returning APIs to callback-taking APIs.
+- You are ok with occasionally getting `ENOENT` errors for failures that
+  are actually related to something other than a missing file system entry.
+- You don't need/want a CLI.
+- You need to override the `fs` methods in use.
+
+## use mkdirp 0.x if:
+
+- You need to know the first directory that was created.
+- You need (or at least, are ok with) a CLI.
+- You need to override the `fs` methods in use.
+- You're ok with using callbacks instead of promises.
+- You are not running on Windows, where the root-level ENOENT errors can
+  lead to infinite regress.
+- You think vinyl just sounds warmer and richer for some weird reason.
+- You are supporting truly ancient Node.js versions, before even the advent
+  of a `Promise` language primitive.  (Please don't.  You deserve better.)
+
+# cli
+
+This package also ships with a `mkdirp` command.
+
+```
+$ mkdirp -h
+
+usage: mkdirp [DIR1,DIR2..] {OPTIONS}
+
+  Create each supplied directory including any necessary parent directories
+  that don't yet exist.
+
+  If the directory already exists, do nothing.
+
+OPTIONS are:
+
+  -m<mode>       If a directory needs to be created, set the mode as an octal
+  --mode=<mode>  permission string.
+
+  -v --version   Print the mkdirp version number
+
+  -h --help      Print this helpful banner
+
+  -p --print     Print the first directories created for each path provided
+
+  --manual       Use manual implementation, even if native is available
+```
+
+# install
+
+With [npm](http://npmjs.org) do:
+
+```
+npm install mkdirp
+```
+
+to get the library locally, or
+
+```
+npm install -g mkdirp
+```
+
+to get the command everywhere, or
+
+```
+npx mkdirp ...
+```
+
+to run the command without installing it globally.
+
+# platform support
+
+This module works on node v8, but only v10 and above are officially
+supported, as Node v8 reached its LTS end of life 2020-01-01, which is in
+the past, as of this writing.
+
+# license
+
+MIT
diff --git a/server/node_modules/@npmcli/move-file/package.json b/server/node_modules/@npmcli/move-file/package.json
new file mode 100644
index 0000000..0c066db
--- /dev/null
+++ b/server/node_modules/@npmcli/move-file/package.json
@@ -0,0 +1,34 @@
+{
+  "name": "@npmcli/move-file",
+  "version": "1.1.2",
+  "files": [
+    "index.js"
+  ],
+  "description": "move a file (fork of move-file)",
+  "dependencies": {
+    "mkdirp": "^1.0.4",
+    "rimraf": "^3.0.2"
+  },
+  "devDependencies": {
+    "require-inject": "^1.4.4",
+    "tap": "^14.10.7"
+  },
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/npm/move-file"
+  },
+  "tap": {
+    "check-coverage": true
+  },
+  "license": "MIT",
+  "engines": {
+    "node": ">=10"
+  }
+}
diff --git a/server/node_modules/@tootallnate/once/dist/index.d.ts b/server/node_modules/@tootallnate/once/dist/index.d.ts
new file mode 100644
index 0000000..a7efe94
--- /dev/null
+++ b/server/node_modules/@tootallnate/once/dist/index.d.ts
@@ -0,0 +1,14 @@
+/// <reference types="node" />
+import { EventEmitter } from 'events';
+declare function once<T>(emitter: EventEmitter, name: string): once.CancelablePromise<T>;
+declare namespace once {
+    interface CancelFunction {
+        (): void;
+    }
+    interface CancelablePromise<T> extends Promise<T> {
+        cancel: CancelFunction;
+    }
+    type CancellablePromise<T> = CancelablePromise<T>;
+    function spread<T extends any[]>(emitter: EventEmitter, name: string): once.CancelablePromise<T>;
+}
+export = once;
diff --git a/server/node_modules/@tootallnate/once/dist/index.js b/server/node_modules/@tootallnate/once/dist/index.js
new file mode 100644
index 0000000..bfd0dc8
--- /dev/null
+++ b/server/node_modules/@tootallnate/once/dist/index.js
@@ -0,0 +1,39 @@
+"use strict";
+function noop() { }
+function once(emitter, name) {
+    const o = once.spread(emitter, name);
+    const r = o.then((args) => args[0]);
+    r.cancel = o.cancel;
+    return r;
+}
+(function (once) {
+    function spread(emitter, name) {
+        let c = null;
+        const p = new Promise((resolve, reject) => {
+            function cancel() {
+                emitter.removeListener(name, onEvent);
+                emitter.removeListener('error', onError);
+                p.cancel = noop;
+            }
+            function onEvent(...args) {
+                cancel();
+                resolve(args);
+            }
+            function onError(err) {
+                cancel();
+                reject(err);
+            }
+            c = cancel;
+            emitter.on(name, onEvent);
+            emitter.on('error', onError);
+        });
+        if (!c) {
+            throw new TypeError('Could not get `cancel()` function');
+        }
+        p.cancel = c;
+        return p;
+    }
+    once.spread = spread;
+})(once || (once = {}));
+module.exports = once;
+//# sourceMappingURL=index.js.map
\ No newline at end of file
diff --git a/server/node_modules/@tootallnate/once/dist/index.js.map b/server/node_modules/@tootallnate/once/dist/index.js.map
new file mode 100644
index 0000000..30d2049
--- /dev/null
+++ b/server/node_modules/@tootallnate/once/dist/index.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"index.js","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":";AAEA,SAAS,IAAI,KAAI,CAAC;AAElB,SAAS,IAAI,CACZ,OAAqB,EACrB,IAAY;IAEZ,MAAM,CAAC,GAAG,IAAI,CAAC,MAAM,CAAM,OAAO,EAAE,IAAI,CAAC,CAAC;IAC1C,MAAM,CAAC,GAAG,CAAC,CAAC,IAAI,CAAC,CAAC,IAAS,EAAE,EAAE,CAAC,IAAI,CAAC,CAAC,CAAC,CAA8B,CAAC;IACtE,CAAC,CAAC,MAAM,GAAG,CAAC,CAAC,MAAM,CAAC;IACpB,OAAO,CAAC,CAAC;AACV,CAAC;AAED,WAAU,IAAI;IAWb,SAAgB,MAAM,CACrB,OAAqB,EACrB,IAAY;QAEZ,IAAI,CAAC,GAA+B,IAAI,CAAC;QACzC,MAAM,CAAC,GAAG,IAAI,OAAO,CAAI,CAAC,OAAO,EAAE,MAAM,EAAE,EAAE;YAC5C,SAAS,MAAM;gBACd,OAAO,CAAC,cAAc,CAAC,IAAI,EAAE,OAAO,CAAC,CAAC;gBACtC,OAAO,CAAC,cAAc,CAAC,OAAO,EAAE,OAAO,CAAC,CAAC;gBACzC,CAAC,CAAC,MAAM,GAAG,IAAI,CAAC;YACjB,CAAC;YACD,SAAS,OAAO,CAAC,GAAG,IAAW;gBAC9B,MAAM,EAAE,CAAC;gBACT,OAAO,CAAC,IAAS,CAAC,CAAC;YACpB,CAAC;YACD,SAAS,OAAO,CAAC,GAAU;gBAC1B,MAAM,EAAE,CAAC;gBACT,MAAM,CAAC,GAAG,CAAC,CAAC;YACb,CAAC;YACD,CAAC,GAAG,MAAM,CAAC;YACX,OAAO,CAAC,EAAE,CAAC,IAAI,EAAE,OAAO,CAAC,CAAC;YAC1B,OAAO,CAAC,EAAE,CAAC,OAAO,EAAE,OAAO,CAAC,CAAC;QAC9B,CAAC,CAA8B,CAAC;QAChC,IAAI,CAAC,CAAC,EAAE;YACP,MAAM,IAAI,SAAS,CAAC,mCAAmC,CAAC,CAAC;SACzD;QACD,CAAC,CAAC,MAAM,GAAG,CAAC,CAAC;QACb,OAAO,CAAC,CAAC;IACV,CAAC;IA5Be,WAAM,SA4BrB,CAAA;AACF,CAAC,EAxCS,IAAI,KAAJ,IAAI,QAwCb;AAED,iBAAS,IAAI,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/@tootallnate/once/package.json b/server/node_modules/@tootallnate/once/package.json
new file mode 100644
index 0000000..8343f9f
--- /dev/null
+++ b/server/node_modules/@tootallnate/once/package.json
@@ -0,0 +1,45 @@
+{
+  "name": "@tootallnate/once",
+  "version": "1.1.2",
+  "description": "Creates a Promise that waits for a single event",
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "prebuild": "rimraf dist",
+    "build": "tsc",
+    "test": "mocha --reporter spec",
+    "test-lint": "eslint src --ext .js,.ts",
+    "prepublishOnly": "npm run build"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/TooTallNate/once.git"
+  },
+  "keywords": [],
+  "author": "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io/)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/TooTallNate/once/issues"
+  },
+  "devDependencies": {
+    "@types/node": "^12.12.11",
+    "@typescript-eslint/eslint-plugin": "1.6.0",
+    "@typescript-eslint/parser": "1.1.0",
+    "eslint": "5.16.0",
+    "eslint-config-airbnb": "17.1.0",
+    "eslint-config-prettier": "4.1.0",
+    "eslint-import-resolver-typescript": "1.1.1",
+    "eslint-plugin-import": "2.16.0",
+    "eslint-plugin-jsx-a11y": "6.2.1",
+    "eslint-plugin-react": "7.12.4",
+    "mocha": "^6.2.2",
+    "rimraf": "^3.0.0",
+    "typescript": "^3.7.3"
+  },
+  "engines": {
+    "node": ">= 6"
+  }
+}
diff --git a/server/node_modules/abbrev/LICENSE b/server/node_modules/abbrev/LICENSE
new file mode 100644
index 0000000..9bcfa9d
--- /dev/null
+++ b/server/node_modules/abbrev/LICENSE
@@ -0,0 +1,46 @@
+This software is dual-licensed under the ISC and MIT licenses.
+You may use this software under EITHER of the following licenses.
+
+----------
+
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+----------
+
+Copyright Isaac Z. Schlueter and Contributors
+All rights reserved.
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/abbrev/README.md b/server/node_modules/abbrev/README.md
new file mode 100644
index 0000000..99746fe
--- /dev/null
+++ b/server/node_modules/abbrev/README.md
@@ -0,0 +1,23 @@
+# abbrev-js
+
+Just like [ruby's Abbrev](http://apidock.com/ruby/Abbrev).
+
+Usage:
+
+    var abbrev = require("abbrev");
+    abbrev("foo", "fool", "folding", "flop");
+    
+    // returns:
+    { fl: 'flop'
+    , flo: 'flop'
+    , flop: 'flop'
+    , fol: 'folding'
+    , fold: 'folding'
+    , foldi: 'folding'
+    , foldin: 'folding'
+    , folding: 'folding'
+    , foo: 'foo'
+    , fool: 'fool'
+    }
+
+This is handy for command-line scripts, or other cases where you want to be able to accept shorthands.
diff --git a/server/node_modules/abbrev/abbrev.js b/server/node_modules/abbrev/abbrev.js
new file mode 100644
index 0000000..7b1dc5d
--- /dev/null
+++ b/server/node_modules/abbrev/abbrev.js
@@ -0,0 +1,61 @@
+module.exports = exports = abbrev.abbrev = abbrev
+
+abbrev.monkeyPatch = monkeyPatch
+
+function monkeyPatch () {
+  Object.defineProperty(Array.prototype, 'abbrev', {
+    value: function () { return abbrev(this) },
+    enumerable: false, configurable: true, writable: true
+  })
+
+  Object.defineProperty(Object.prototype, 'abbrev', {
+    value: function () { return abbrev(Object.keys(this)) },
+    enumerable: false, configurable: true, writable: true
+  })
+}
+
+function abbrev (list) {
+  if (arguments.length !== 1 || !Array.isArray(list)) {
+    list = Array.prototype.slice.call(arguments, 0)
+  }
+  for (var i = 0, l = list.length, args = [] ; i < l ; i ++) {
+    args[i] = typeof list[i] === "string" ? list[i] : String(list[i])
+  }
+
+  // sort them lexicographically, so that they're next to their nearest kin
+  args = args.sort(lexSort)
+
+  // walk through each, seeing how much it has in common with the next and previous
+  var abbrevs = {}
+    , prev = ""
+  for (var i = 0, l = args.length ; i < l ; i ++) {
+    var current = args[i]
+      , next = args[i + 1] || ""
+      , nextMatches = true
+      , prevMatches = true
+    if (current === next) continue
+    for (var j = 0, cl = current.length ; j < cl ; j ++) {
+      var curChar = current.charAt(j)
+      nextMatches = nextMatches && curChar === next.charAt(j)
+      prevMatches = prevMatches && curChar === prev.charAt(j)
+      if (!nextMatches && !prevMatches) {
+        j ++
+        break
+      }
+    }
+    prev = current
+    if (j === cl) {
+      abbrevs[current] = current
+      continue
+    }
+    for (var a = current.substr(0, j) ; j <= cl ; j ++) {
+      abbrevs[a] = current
+      a += current.charAt(j)
+    }
+  }
+  return abbrevs
+}
+
+function lexSort (a, b) {
+  return a === b ? 0 : a > b ? 1 : -1
+}
diff --git a/server/node_modules/abbrev/package.json b/server/node_modules/abbrev/package.json
new file mode 100644
index 0000000..bf4e801
--- /dev/null
+++ b/server/node_modules/abbrev/package.json
@@ -0,0 +1,21 @@
+{
+  "name": "abbrev",
+  "version": "1.1.1",
+  "description": "Like ruby's abbrev module, but in js",
+  "author": "Isaac Z. Schlueter <i@izs.me>",
+  "main": "abbrev.js",
+  "scripts": {
+    "test": "tap test.js --100",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --all; git push origin --tags"
+  },
+  "repository": "http://github.com/isaacs/abbrev-js",
+  "license": "ISC",
+  "devDependencies": {
+    "tap": "^10.1"
+  },
+  "files": [
+    "abbrev.js"
+  ]
+}
diff --git a/server/node_modules/accepts/HISTORY.md b/server/node_modules/accepts/HISTORY.md
new file mode 100644
index 0000000..cb5990c
--- /dev/null
+++ b/server/node_modules/accepts/HISTORY.md
@@ -0,0 +1,243 @@
+1.3.8 / 2022-02-02
+==================
+
+  * deps: mime-types@~2.1.34
+    - deps: mime-db@~1.51.0
+  * deps: negotiator@0.6.3
+
+1.3.7 / 2019-04-29
+==================
+
+  * deps: negotiator@0.6.2
+    - Fix sorting charset, encoding, and language with extra parameters
+
+1.3.6 / 2019-04-28
+==================
+
+  * deps: mime-types@~2.1.24
+    - deps: mime-db@~1.40.0
+
+1.3.5 / 2018-02-28
+==================
+
+  * deps: mime-types@~2.1.18
+    - deps: mime-db@~1.33.0
+
+1.3.4 / 2017-08-22
+==================
+
+  * deps: mime-types@~2.1.16
+    - deps: mime-db@~1.29.0
+
+1.3.3 / 2016-05-02
+==================
+
+  * deps: mime-types@~2.1.11
+    - deps: mime-db@~1.23.0
+  * deps: negotiator@0.6.1
+    - perf: improve `Accept` parsing speed
+    - perf: improve `Accept-Charset` parsing speed
+    - perf: improve `Accept-Encoding` parsing speed
+    - perf: improve `Accept-Language` parsing speed
+
+1.3.2 / 2016-03-08
+==================
+
+  * deps: mime-types@~2.1.10
+    - Fix extension of `application/dash+xml`
+    - Update primary extension for `audio/mp4`
+    - deps: mime-db@~1.22.0
+
+1.3.1 / 2016-01-19
+==================
+
+  * deps: mime-types@~2.1.9
+    - deps: mime-db@~1.21.0
+
+1.3.0 / 2015-09-29
+==================
+
+  * deps: mime-types@~2.1.7
+    - deps: mime-db@~1.19.0
+  * deps: negotiator@0.6.0
+    - Fix including type extensions in parameters in `Accept` parsing
+    - Fix parsing `Accept` parameters with quoted equals
+    - Fix parsing `Accept` parameters with quoted semicolons
+    - Lazy-load modules from main entry point
+    - perf: delay type concatenation until needed
+    - perf: enable strict mode
+    - perf: hoist regular expressions
+    - perf: remove closures getting spec properties
+    - perf: remove a closure from media type parsing
+    - perf: remove property delete from media type parsing
+
+1.2.13 / 2015-09-06
+===================
+
+  * deps: mime-types@~2.1.6
+    - deps: mime-db@~1.18.0
+
+1.2.12 / 2015-07-30
+===================
+
+  * deps: mime-types@~2.1.4
+    - deps: mime-db@~1.16.0
+
+1.2.11 / 2015-07-16
+===================
+
+  * deps: mime-types@~2.1.3
+    - deps: mime-db@~1.15.0
+
+1.2.10 / 2015-07-01
+===================
+
+  * deps: mime-types@~2.1.2
+    - deps: mime-db@~1.14.0
+
+1.2.9 / 2015-06-08
+==================
+
+  * deps: mime-types@~2.1.1
+    - perf: fix deopt during mapping
+
+1.2.8 / 2015-06-07
+==================
+
+  * deps: mime-types@~2.1.0
+    - deps: mime-db@~1.13.0
+  * perf: avoid argument reassignment & argument slice
+  * perf: avoid negotiator recursive construction
+  * perf: enable strict mode
+  * perf: remove unnecessary bitwise operator
+
+1.2.7 / 2015-05-10
+==================
+
+  * deps: negotiator@0.5.3
+    - Fix media type parameter matching to be case-insensitive
+
+1.2.6 / 2015-05-07
+==================
+
+  * deps: mime-types@~2.0.11
+    - deps: mime-db@~1.9.1
+  * deps: negotiator@0.5.2
+    - Fix comparing media types with quoted values
+    - Fix splitting media types with quoted commas
+
+1.2.5 / 2015-03-13
+==================
+
+  * deps: mime-types@~2.0.10
+    - deps: mime-db@~1.8.0
+
+1.2.4 / 2015-02-14
+==================
+
+  * Support Node.js 0.6
+  * deps: mime-types@~2.0.9
+    - deps: mime-db@~1.7.0
+  * deps: negotiator@0.5.1
+    - Fix preference sorting to be stable for long acceptable lists
+
+1.2.3 / 2015-01-31
+==================
+
+  * deps: mime-types@~2.0.8
+    - deps: mime-db@~1.6.0
+
+1.2.2 / 2014-12-30
+==================
+
+  * deps: mime-types@~2.0.7
+    - deps: mime-db@~1.5.0
+
+1.2.1 / 2014-12-30
+==================
+
+  * deps: mime-types@~2.0.5
+    - deps: mime-db@~1.3.1
+
+1.2.0 / 2014-12-19
+==================
+
+  * deps: negotiator@0.5.0
+    - Fix list return order when large accepted list
+    - Fix missing identity encoding when q=0 exists
+    - Remove dynamic building of Negotiator class
+
+1.1.4 / 2014-12-10
+==================
+
+  * deps: mime-types@~2.0.4
+    - deps: mime-db@~1.3.0
+
+1.1.3 / 2014-11-09
+==================
+
+  * deps: mime-types@~2.0.3
+    - deps: mime-db@~1.2.0
+
+1.1.2 / 2014-10-14
+==================
+
+  * deps: negotiator@0.4.9
+    - Fix error when media type has invalid parameter
+
+1.1.1 / 2014-09-28
+==================
+
+  * deps: mime-types@~2.0.2
+    - deps: mime-db@~1.1.0
+  * deps: negotiator@0.4.8
+    - Fix all negotiations to be case-insensitive
+    - Stable sort preferences of same quality according to client order
+
+1.1.0 / 2014-09-02
+==================
+
+  * update `mime-types`
+
+1.0.7 / 2014-07-04
+==================
+
+  * Fix wrong type returned from `type` when match after unknown extension
+
+1.0.6 / 2014-06-24
+==================
+
+  * deps: negotiator@0.4.7
+
+1.0.5 / 2014-06-20
+==================
+
+ * fix crash when unknown extension given
+
+1.0.4 / 2014-06-19
+==================
+
+  * use `mime-types`
+
+1.0.3 / 2014-06-11
+==================
+
+  * deps: negotiator@0.4.6
+    - Order by specificity when quality is the same
+
+1.0.2 / 2014-05-29
+==================
+
+  * Fix interpretation when header not in request
+  * deps: pin negotiator@0.4.5
+
+1.0.1 / 2014-01-18
+==================
+
+  * Identity encoding isn't always acceptable
+  * deps: negotiator@~0.4.0
+
+1.0.0 / 2013-12-27
+==================
+
+  * Genesis
diff --git a/server/node_modules/accepts/LICENSE b/server/node_modules/accepts/LICENSE
new file mode 100644
index 0000000..0616607
--- /dev/null
+++ b/server/node_modules/accepts/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2014 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/accepts/README.md b/server/node_modules/accepts/README.md
new file mode 100644
index 0000000..82680c5
--- /dev/null
+++ b/server/node_modules/accepts/README.md
@@ -0,0 +1,140 @@
+# accepts
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][github-actions-ci-image]][github-actions-ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Higher level content negotiation based on [negotiator](https://www.npmjs.com/package/negotiator).
+Extracted from [koa](https://www.npmjs.com/package/koa) for general use.
+
+In addition to negotiator, it allows:
+
+- Allows types as an array or arguments list, ie `(['text/html', 'application/json'])`
+  as well as `('text/html', 'application/json')`.
+- Allows type shorthands such as `json`.
+- Returns `false` when no types match
+- Treats non-existent headers as `*`
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install accepts
+```
+
+## API
+
+```js
+var accepts = require('accepts')
+```
+
+### accepts(req)
+
+Create a new `Accepts` object for the given `req`.
+
+#### .charset(charsets)
+
+Return the first accepted charset. If nothing in `charsets` is accepted,
+then `false` is returned.
+
+#### .charsets()
+
+Return the charsets that the request accepts, in the order of the client's
+preference (most preferred first).
+
+#### .encoding(encodings)
+
+Return the first accepted encoding. If nothing in `encodings` is accepted,
+then `false` is returned.
+
+#### .encodings()
+
+Return the encodings that the request accepts, in the order of the client's
+preference (most preferred first).
+
+#### .language(languages)
+
+Return the first accepted language. If nothing in `languages` is accepted,
+then `false` is returned.
+
+#### .languages()
+
+Return the languages that the request accepts, in the order of the client's
+preference (most preferred first).
+
+#### .type(types)
+
+Return the first accepted type (and it is returned as the same text as what
+appears in the `types` array). If nothing in `types` is accepted, then `false`
+is returned.
+
+The `types` array can contain full MIME types or file extensions. Any value
+that is not a full MIME types is passed to `require('mime-types').lookup`.
+
+#### .types()
+
+Return the types that the request accepts, in the order of the client's
+preference (most preferred first).
+
+## Examples
+
+### Simple type negotiation
+
+This simple example shows how to use `accepts` to return a different typed
+respond body based on what the client wants to accept. The server lists it's
+preferences in order and will get back the best match between the client and
+server.
+
+```js
+var accepts = require('accepts')
+var http = require('http')
+
+function app (req, res) {
+  var accept = accepts(req)
+
+  // the order of this list is significant; should be server preferred order
+  switch (accept.type(['json', 'html'])) {
+    case 'json':
+      res.setHeader('Content-Type', 'application/json')
+      res.write('{"hello":"world!"}')
+      break
+    case 'html':
+      res.setHeader('Content-Type', 'text/html')
+      res.write('<b>hello, world!</b>')
+      break
+    default:
+      // the fallback is text/plain, so no need to specify it above
+      res.setHeader('Content-Type', 'text/plain')
+      res.write('hello, world!')
+      break
+  }
+
+  res.end()
+}
+
+http.createServer(app).listen(3000)
+```
+
+You can test this out with the cURL program:
+```sh
+curl -I -H'Accept: text/html' http://localhost:3000/
+```
+
+## License
+
+[MIT](LICENSE)
+
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/accepts/master
+[coveralls-url]: https://coveralls.io/r/jshttp/accepts?branch=master
+[github-actions-ci-image]: https://badgen.net/github/checks/jshttp/accepts/master?label=ci
+[github-actions-ci-url]: https://github.com/jshttp/accepts/actions/workflows/ci.yml
+[node-version-image]: https://badgen.net/npm/node/accepts
+[node-version-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/accepts
+[npm-url]: https://npmjs.org/package/accepts
+[npm-version-image]: https://badgen.net/npm/v/accepts
diff --git a/server/node_modules/accepts/index.js b/server/node_modules/accepts/index.js
new file mode 100644
index 0000000..e9b2f63
--- /dev/null
+++ b/server/node_modules/accepts/index.js
@@ -0,0 +1,238 @@
+/*!
+ * accepts
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var Negotiator = require('negotiator')
+var mime = require('mime-types')
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = Accepts
+
+/**
+ * Create a new Accepts object for the given req.
+ *
+ * @param {object} req
+ * @public
+ */
+
+function Accepts (req) {
+  if (!(this instanceof Accepts)) {
+    return new Accepts(req)
+  }
+
+  this.headers = req.headers
+  this.negotiator = new Negotiator(req)
+}
+
+/**
+ * Check if the given `type(s)` is acceptable, returning
+ * the best match when true, otherwise `undefined`, in which
+ * case you should respond with 406 "Not Acceptable".
+ *
+ * The `type` value may be a single mime type string
+ * such as "application/json", the extension name
+ * such as "json" or an array `["json", "html", "text/plain"]`. When a list
+ * or array is given the _best_ match, if any is returned.
+ *
+ * Examples:
+ *
+ *     // Accept: text/html
+ *     this.types('html');
+ *     // => "html"
+ *
+ *     // Accept: text/*, application/json
+ *     this.types('html');
+ *     // => "html"
+ *     this.types('text/html');
+ *     // => "text/html"
+ *     this.types('json', 'text');
+ *     // => "json"
+ *     this.types('application/json');
+ *     // => "application/json"
+ *
+ *     // Accept: text/*, application/json
+ *     this.types('image/png');
+ *     this.types('png');
+ *     // => undefined
+ *
+ *     // Accept: text/*;q=.5, application/json
+ *     this.types(['html', 'json']);
+ *     this.types('html', 'json');
+ *     // => "json"
+ *
+ * @param {String|Array} types...
+ * @return {String|Array|Boolean}
+ * @public
+ */
+
+Accepts.prototype.type =
+Accepts.prototype.types = function (types_) {
+  var types = types_
+
+  // support flattened arguments
+  if (types && !Array.isArray(types)) {
+    types = new Array(arguments.length)
+    for (var i = 0; i < types.length; i++) {
+      types[i] = arguments[i]
+    }
+  }
+
+  // no types, return all requested types
+  if (!types || types.length === 0) {
+    return this.negotiator.mediaTypes()
+  }
+
+  // no accept header, return first given type
+  if (!this.headers.accept) {
+    return types[0]
+  }
+
+  var mimes = types.map(extToMime)
+  var accepts = this.negotiator.mediaTypes(mimes.filter(validMime))
+  var first = accepts[0]
+
+  return first
+    ? types[mimes.indexOf(first)]
+    : false
+}
+
+/**
+ * Return accepted encodings or best fit based on `encodings`.
+ *
+ * Given `Accept-Encoding: gzip, deflate`
+ * an array sorted by quality is returned:
+ *
+ *     ['gzip', 'deflate']
+ *
+ * @param {String|Array} encodings...
+ * @return {String|Array}
+ * @public
+ */
+
+Accepts.prototype.encoding =
+Accepts.prototype.encodings = function (encodings_) {
+  var encodings = encodings_
+
+  // support flattened arguments
+  if (encodings && !Array.isArray(encodings)) {
+    encodings = new Array(arguments.length)
+    for (var i = 0; i < encodings.length; i++) {
+      encodings[i] = arguments[i]
+    }
+  }
+
+  // no encodings, return all requested encodings
+  if (!encodings || encodings.length === 0) {
+    return this.negotiator.encodings()
+  }
+
+  return this.negotiator.encodings(encodings)[0] || false
+}
+
+/**
+ * Return accepted charsets or best fit based on `charsets`.
+ *
+ * Given `Accept-Charset: utf-8, iso-8859-1;q=0.2, utf-7;q=0.5`
+ * an array sorted by quality is returned:
+ *
+ *     ['utf-8', 'utf-7', 'iso-8859-1']
+ *
+ * @param {String|Array} charsets...
+ * @return {String|Array}
+ * @public
+ */
+
+Accepts.prototype.charset =
+Accepts.prototype.charsets = function (charsets_) {
+  var charsets = charsets_
+
+  // support flattened arguments
+  if (charsets && !Array.isArray(charsets)) {
+    charsets = new Array(arguments.length)
+    for (var i = 0; i < charsets.length; i++) {
+      charsets[i] = arguments[i]
+    }
+  }
+
+  // no charsets, return all requested charsets
+  if (!charsets || charsets.length === 0) {
+    return this.negotiator.charsets()
+  }
+
+  return this.negotiator.charsets(charsets)[0] || false
+}
+
+/**
+ * Return accepted languages or best fit based on `langs`.
+ *
+ * Given `Accept-Language: en;q=0.8, es, pt`
+ * an array sorted by quality is returned:
+ *
+ *     ['es', 'pt', 'en']
+ *
+ * @param {String|Array} langs...
+ * @return {Array|String}
+ * @public
+ */
+
+Accepts.prototype.lang =
+Accepts.prototype.langs =
+Accepts.prototype.language =
+Accepts.prototype.languages = function (languages_) {
+  var languages = languages_
+
+  // support flattened arguments
+  if (languages && !Array.isArray(languages)) {
+    languages = new Array(arguments.length)
+    for (var i = 0; i < languages.length; i++) {
+      languages[i] = arguments[i]
+    }
+  }
+
+  // no languages, return all requested languages
+  if (!languages || languages.length === 0) {
+    return this.negotiator.languages()
+  }
+
+  return this.negotiator.languages(languages)[0] || false
+}
+
+/**
+ * Convert extnames to mime.
+ *
+ * @param {String} type
+ * @return {String}
+ * @private
+ */
+
+function extToMime (type) {
+  return type.indexOf('/') === -1
+    ? mime.lookup(type)
+    : type
+}
+
+/**
+ * Check if mime is valid.
+ *
+ * @param {String} type
+ * @return {String}
+ * @private
+ */
+
+function validMime (type) {
+  return typeof type === 'string'
+}
diff --git a/server/node_modules/accepts/package.json b/server/node_modules/accepts/package.json
new file mode 100644
index 0000000..0f2d15d
--- /dev/null
+++ b/server/node_modules/accepts/package.json
@@ -0,0 +1,47 @@
+{
+  "name": "accepts",
+  "description": "Higher-level content negotiation",
+  "version": "1.3.8",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "license": "MIT",
+  "repository": "jshttp/accepts",
+  "dependencies": {
+    "mime-types": "~2.1.34",
+    "negotiator": "0.6.3"
+  },
+  "devDependencies": {
+    "deep-equal": "1.0.1",
+    "eslint": "7.32.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.25.4",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "4.3.1",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "9.2.0",
+    "nyc": "15.1.0"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --check-leaks --bail test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  },
+  "keywords": [
+    "content",
+    "negotiation",
+    "accept",
+    "accepts"
+  ]
+}
diff --git a/server/node_modules/agent-base/README.md b/server/node_modules/agent-base/README.md
new file mode 100644
index 0000000..256f1f3
--- /dev/null
+++ b/server/node_modules/agent-base/README.md
@@ -0,0 +1,145 @@
+agent-base
+==========
+### Turn a function into an [`http.Agent`][http.Agent] instance
+[![Build Status](https://github.com/TooTallNate/node-agent-base/workflows/Node%20CI/badge.svg)](https://github.com/TooTallNate/node-agent-base/actions?workflow=Node+CI)
+
+This module provides an `http.Agent` generator. That is, you pass it an async
+callback function, and it returns a new `http.Agent` instance that will invoke the
+given callback function when sending outbound HTTP requests.
+
+#### Some subclasses:
+
+Here's some more interesting uses of `agent-base`.
+Send a pull request to list yours!
+
+ * [`http-proxy-agent`][http-proxy-agent]: An HTTP(s) proxy `http.Agent` implementation for HTTP endpoints
+ * [`https-proxy-agent`][https-proxy-agent]: An HTTP(s) proxy `http.Agent` implementation for HTTPS endpoints
+ * [`pac-proxy-agent`][pac-proxy-agent]: A PAC file proxy `http.Agent` implementation for HTTP and HTTPS
+ * [`socks-proxy-agent`][socks-proxy-agent]: A SOCKS proxy `http.Agent` implementation for HTTP and HTTPS
+
+
+Installation
+------------
+
+Install with `npm`:
+
+``` bash
+$ npm install agent-base
+```
+
+
+Example
+-------
+
+Here's a minimal example that creates a new `net.Socket` connection to the server
+for every HTTP request (i.e. the equivalent of `agent: false` option):
+
+```js
+var net = require('net');
+var tls = require('tls');
+var url = require('url');
+var http = require('http');
+var agent = require('agent-base');
+
+var endpoint = 'http://nodejs.org/api/';
+var parsed = url.parse(endpoint);
+
+// This is the important part!
+parsed.agent = agent(function (req, opts) {
+  var socket;
+  // `secureEndpoint` is true when using the https module
+  if (opts.secureEndpoint) {
+    socket = tls.connect(opts);
+  } else {
+    socket = net.connect(opts);
+  }
+  return socket;
+});
+
+// Everything else works just like normal...
+http.get(parsed, function (res) {
+  console.log('"response" event!', res.headers);
+  res.pipe(process.stdout);
+});
+```
+
+Returning a Promise or using an `async` function is also supported:
+
+```js
+agent(async function (req, opts) {
+  await sleep(1000);
+  // etc…
+});
+```
+
+Return another `http.Agent` instance to "pass through" the responsibility
+for that HTTP request to that agent:
+
+```js
+agent(function (req, opts) {
+  return opts.secureEndpoint ? https.globalAgent : http.globalAgent;
+});
+```
+
+
+API
+---
+
+## Agent(Function callback[, Object options]) → [http.Agent][]
+
+Creates a base `http.Agent` that will execute the callback function `callback`
+for every HTTP request that it is used as the `agent` for. The callback function
+is responsible for creating a `stream.Duplex` instance of some kind that will be
+used as the underlying socket in the HTTP request.
+
+The `options` object accepts the following properties:
+
+  * `timeout` - Number - Timeout for the `callback()` function in milliseconds. Defaults to Infinity (optional).
+
+The callback function should have the following signature:
+
+### callback(http.ClientRequest req, Object options, Function cb) → undefined
+
+The ClientRequest `req` can be accessed to read request headers and
+and the path, etc. The `options` object contains the options passed
+to the `http.request()`/`https.request()` function call, and is formatted
+to be directly passed to `net.connect()`/`tls.connect()`, or however
+else you want a Socket to be created. Pass the created socket to
+the callback function `cb` once created, and the HTTP request will
+continue to proceed.
+
+If the `https` module is used to invoke the HTTP request, then the
+`secureEndpoint` property on `options` _will be set to `true`_.
+
+
+License
+-------
+
+(The MIT License)
+
+Copyright (c) 2013 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+[http-proxy-agent]: https://github.com/TooTallNate/node-http-proxy-agent
+[https-proxy-agent]: https://github.com/TooTallNate/node-https-proxy-agent
+[pac-proxy-agent]: https://github.com/TooTallNate/node-pac-proxy-agent
+[socks-proxy-agent]: https://github.com/TooTallNate/node-socks-proxy-agent
+[http.Agent]: https://nodejs.org/api/http.html#http_class_http_agent
diff --git a/server/node_modules/agent-base/dist/src/index.d.ts b/server/node_modules/agent-base/dist/src/index.d.ts
new file mode 100644
index 0000000..bc4ab74
--- /dev/null
+++ b/server/node_modules/agent-base/dist/src/index.d.ts
@@ -0,0 +1,78 @@
+/// <reference types="node" />
+import net from 'net';
+import http from 'http';
+import https from 'https';
+import { Duplex } from 'stream';
+import { EventEmitter } from 'events';
+declare function createAgent(opts?: createAgent.AgentOptions): createAgent.Agent;
+declare function createAgent(callback: createAgent.AgentCallback, opts?: createAgent.AgentOptions): createAgent.Agent;
+declare namespace createAgent {
+    interface ClientRequest extends http.ClientRequest {
+        _last?: boolean;
+        _hadError?: boolean;
+        method: string;
+    }
+    interface AgentRequestOptions {
+        host?: string;
+        path?: string;
+        port: number;
+    }
+    interface HttpRequestOptions extends AgentRequestOptions, Omit<http.RequestOptions, keyof AgentRequestOptions> {
+        secureEndpoint: false;
+    }
+    interface HttpsRequestOptions extends AgentRequestOptions, Omit<https.RequestOptions, keyof AgentRequestOptions> {
+        secureEndpoint: true;
+    }
+    type RequestOptions = HttpRequestOptions | HttpsRequestOptions;
+    type AgentLike = Pick<createAgent.Agent, 'addRequest'> | http.Agent;
+    type AgentCallbackReturn = Duplex | AgentLike;
+    type AgentCallbackCallback = (err?: Error | null, socket?: createAgent.AgentCallbackReturn) => void;
+    type AgentCallbackPromise = (req: createAgent.ClientRequest, opts: createAgent.RequestOptions) => createAgent.AgentCallbackReturn | Promise<createAgent.AgentCallbackReturn>;
+    type AgentCallback = typeof Agent.prototype.callback;
+    type AgentOptions = {
+        timeout?: number;
+    };
+    /**
+     * Base `http.Agent` implementation.
+     * No pooling/keep-alive is implemented by default.
+     *
+     * @param {Function} callback
+     * @api public
+     */
+    class Agent extends EventEmitter {
+        timeout: number | null;
+        maxFreeSockets: number;
+        maxTotalSockets: number;
+        maxSockets: number;
+        sockets: {
+            [key: string]: net.Socket[];
+        };
+        freeSockets: {
+            [key: string]: net.Socket[];
+        };
+        requests: {
+            [key: string]: http.IncomingMessage[];
+        };
+        options: https.AgentOptions;
+        private promisifiedCallback?;
+        private explicitDefaultPort?;
+        private explicitProtocol?;
+        constructor(callback?: createAgent.AgentCallback | createAgent.AgentOptions, _opts?: createAgent.AgentOptions);
+        get defaultPort(): number;
+        set defaultPort(v: number);
+        get protocol(): string;
+        set protocol(v: string);
+        callback(req: createAgent.ClientRequest, opts: createAgent.RequestOptions, fn: createAgent.AgentCallbackCallback): void;
+        callback(req: createAgent.ClientRequest, opts: createAgent.RequestOptions): createAgent.AgentCallbackReturn | Promise<createAgent.AgentCallbackReturn>;
+        /**
+         * Called by node-core's "_http_client.js" module when creating
+         * a new HTTP request with this Agent instance.
+         *
+         * @api public
+         */
+        addRequest(req: ClientRequest, _opts: RequestOptions): void;
+        freeSocket(socket: net.Socket, opts: AgentOptions): void;
+        destroy(): void;
+    }
+}
+export = createAgent;
diff --git a/server/node_modules/agent-base/dist/src/index.js b/server/node_modules/agent-base/dist/src/index.js
new file mode 100644
index 0000000..bfd9e22
--- /dev/null
+++ b/server/node_modules/agent-base/dist/src/index.js
@@ -0,0 +1,203 @@
+"use strict";
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+const events_1 = require("events");
+const debug_1 = __importDefault(require("debug"));
+const promisify_1 = __importDefault(require("./promisify"));
+const debug = debug_1.default('agent-base');
+function isAgent(v) {
+    return Boolean(v) && typeof v.addRequest === 'function';
+}
+function isSecureEndpoint() {
+    const { stack } = new Error();
+    if (typeof stack !== 'string')
+        return false;
+    return stack.split('\n').some(l => l.indexOf('(https.js:') !== -1 || l.indexOf('node:https:') !== -1);
+}
+function createAgent(callback, opts) {
+    return new createAgent.Agent(callback, opts);
+}
+(function (createAgent) {
+    /**
+     * Base `http.Agent` implementation.
+     * No pooling/keep-alive is implemented by default.
+     *
+     * @param {Function} callback
+     * @api public
+     */
+    class Agent extends events_1.EventEmitter {
+        constructor(callback, _opts) {
+            super();
+            let opts = _opts;
+            if (typeof callback === 'function') {
+                this.callback = callback;
+            }
+            else if (callback) {
+                opts = callback;
+            }
+            // Timeout for the socket to be returned from the callback
+            this.timeout = null;
+            if (opts && typeof opts.timeout === 'number') {
+                this.timeout = opts.timeout;
+            }
+            // These aren't actually used by `agent-base`, but are required
+            // for the TypeScript definition files in `@types/node` :/
+            this.maxFreeSockets = 1;
+            this.maxSockets = 1;
+            this.maxTotalSockets = Infinity;
+            this.sockets = {};
+            this.freeSockets = {};
+            this.requests = {};
+            this.options = {};
+        }
+        get defaultPort() {
+            if (typeof this.explicitDefaultPort === 'number') {
+                return this.explicitDefaultPort;
+            }
+            return isSecureEndpoint() ? 443 : 80;
+        }
+        set defaultPort(v) {
+            this.explicitDefaultPort = v;
+        }
+        get protocol() {
+            if (typeof this.explicitProtocol === 'string') {
+                return this.explicitProtocol;
+            }
+            return isSecureEndpoint() ? 'https:' : 'http:';
+        }
+        set protocol(v) {
+            this.explicitProtocol = v;
+        }
+        callback(req, opts, fn) {
+            throw new Error('"agent-base" has no default implementation, you must subclass and override `callback()`');
+        }
+        /**
+         * Called by node-core's "_http_client.js" module when creating
+         * a new HTTP request with this Agent instance.
+         *
+         * @api public
+         */
+        addRequest(req, _opts) {
+            const opts = Object.assign({}, _opts);
+            if (typeof opts.secureEndpoint !== 'boolean') {
+                opts.secureEndpoint = isSecureEndpoint();
+            }
+            if (opts.host == null) {
+                opts.host = 'localhost';
+            }
+            if (opts.port == null) {
+                opts.port = opts.secureEndpoint ? 443 : 80;
+            }
+            if (opts.protocol == null) {
+                opts.protocol = opts.secureEndpoint ? 'https:' : 'http:';
+            }
+            if (opts.host && opts.path) {
+                // If both a `host` and `path` are specified then it's most
+                // likely the result of a `url.parse()` call... we need to
+                // remove the `path` portion so that `net.connect()` doesn't
+                // attempt to open that as a unix socket file.
+                delete opts.path;
+            }
+            delete opts.agent;
+            delete opts.hostname;
+            delete opts._defaultAgent;
+            delete opts.defaultPort;
+            delete opts.createConnection;
+            // Hint to use "Connection: close"
+            // XXX: non-documented `http` module API :(
+            req._last = true;
+            req.shouldKeepAlive = false;
+            let timedOut = false;
+            let timeoutId = null;
+            const timeoutMs = opts.timeout || this.timeout;
+            const onerror = (err) => {
+                if (req._hadError)
+                    return;
+                req.emit('error', err);
+                // For Safety. Some additional errors might fire later on
+                // and we need to make sure we don't double-fire the error event.
+                req._hadError = true;
+            };
+            const ontimeout = () => {
+                timeoutId = null;
+                timedOut = true;
+                const err = new Error(`A "socket" was not created for HTTP request before ${timeoutMs}ms`);
+                err.code = 'ETIMEOUT';
+                onerror(err);
+            };
+            const callbackError = (err) => {
+                if (timedOut)
+                    return;
+                if (timeoutId !== null) {
+                    clearTimeout(timeoutId);
+                    timeoutId = null;
+                }
+                onerror(err);
+            };
+            const onsocket = (socket) => {
+                if (timedOut)
+                    return;
+                if (timeoutId != null) {
+                    clearTimeout(timeoutId);
+                    timeoutId = null;
+                }
+                if (isAgent(socket)) {
+                    // `socket` is actually an `http.Agent` instance, so
+                    // relinquish responsibility for this `req` to the Agent
+                    // from here on
+                    debug('Callback returned another Agent instance %o', socket.constructor.name);
+                    socket.addRequest(req, opts);
+                    return;
+                }
+                if (socket) {
+                    socket.once('free', () => {
+                        this.freeSocket(socket, opts);
+                    });
+                    req.onSocket(socket);
+                    return;
+                }
+                const err = new Error(`no Duplex stream was returned to agent-base for \`${req.method} ${req.path}\``);
+                onerror(err);
+            };
+            if (typeof this.callback !== 'function') {
+                onerror(new Error('`callback` is not defined'));
+                return;
+            }
+            if (!this.promisifiedCallback) {
+                if (this.callback.length >= 3) {
+                    debug('Converting legacy callback function to promise');
+                    this.promisifiedCallback = promisify_1.default(this.callback);
+                }
+                else {
+                    this.promisifiedCallback = this.callback;
+                }
+            }
+            if (typeof timeoutMs === 'number' && timeoutMs > 0) {
+                timeoutId = setTimeout(ontimeout, timeoutMs);
+            }
+            if ('port' in opts && typeof opts.port !== 'number') {
+                opts.port = Number(opts.port);
+            }
+            try {
+                debug('Resolving socket for %o request: %o', opts.protocol, `${req.method} ${req.path}`);
+                Promise.resolve(this.promisifiedCallback(req, opts)).then(onsocket, callbackError);
+            }
+            catch (err) {
+                Promise.reject(err).catch(callbackError);
+            }
+        }
+        freeSocket(socket, opts) {
+            debug('Freeing socket %o %o', socket.constructor.name, opts);
+            socket.destroy();
+        }
+        destroy() {
+            debug('Destroying agent %o', this.constructor.name);
+        }
+    }
+    createAgent.Agent = Agent;
+    // So that `instanceof` works correctly
+    createAgent.prototype = createAgent.Agent.prototype;
+})(createAgent || (createAgent = {}));
+module.exports = createAgent;
+//# sourceMappingURL=index.js.map
\ No newline at end of file
diff --git a/server/node_modules/agent-base/dist/src/index.js.map b/server/node_modules/agent-base/dist/src/index.js.map
new file mode 100644
index 0000000..bd118ab
--- /dev/null
+++ b/server/node_modules/agent-base/dist/src/index.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"index.js","sourceRoot":"","sources":["../../src/index.ts"],"names":[],"mappings":";;;;AAIA,mCAAsC;AACtC,kDAAgC;AAChC,4DAAoC;AAEpC,MAAM,KAAK,GAAG,eAAW,CAAC,YAAY,CAAC,CAAC;AAExC,SAAS,OAAO,CAAC,CAAM;IACtB,OAAO,OAAO,CAAC,CAAC,CAAC,IAAI,OAAO,CAAC,CAAC,UAAU,KAAK,UAAU,CAAC;AACzD,CAAC;AAED,SAAS,gBAAgB;IACxB,MAAM,EAAE,KAAK,EAAE,GAAG,IAAI,KAAK,EAAE,CAAC;IAC9B,IAAI,OAAO,KAAK,KAAK,QAAQ;QAAE,OAAO,KAAK,CAAC;IAC5C,OAAO,KAAK,CAAC,KAAK,CAAC,IAAI,CAAC,CAAC,IAAI,CAAC,CAAC,CAAC,EAAE,CAAC,CAAC,CAAC,OAAO,CAAC,YAAY,CAAC,KAAK,CAAC,CAAC,IAAK,CAAC,CAAC,OAAO,CAAC,aAAa,CAAC,KAAK,CAAC,CAAC,CAAC,CAAC;AACxG,CAAC;AAOD,SAAS,WAAW,CACnB,QAA+D,EAC/D,IAA+B;IAE/B,OAAO,IAAI,WAAW,CAAC,KAAK,CAAC,QAAQ,EAAE,IAAI,CAAC,CAAC;AAC9C,CAAC;AAED,WAAU,WAAW;IAmDpB;;;;;;OAMG;IACH,MAAa,KAAM,SAAQ,qBAAY;QAmBtC,YACC,QAA+D,EAC/D,KAAgC;YAEhC,KAAK,EAAE,CAAC;YAER,IAAI,IAAI,GAAG,KAAK,CAAC;YACjB,IAAI,OAAO,QAAQ,KAAK,UAAU,EAAE;gBACnC,IAAI,CAAC,QAAQ,GAAG,QAAQ,CAAC;aACzB;iBAAM,IAAI,QAAQ,EAAE;gBACpB,IAAI,GAAG,QAAQ,CAAC;aAChB;YAED,0DAA0D;YAC1D,IAAI,CAAC,OAAO,GAAG,IAAI,CAAC;YACpB,IAAI,IAAI,IAAI,OAAO,IAAI,CAAC,OAAO,KAAK,QAAQ,EAAE;gBAC7C,IAAI,CAAC,OAAO,GAAG,IAAI,CAAC,OAAO,CAAC;aAC5B;YAED,+DAA+D;YAC/D,0DAA0D;YAC1D,IAAI,CAAC,cAAc,GAAG,CAAC,CAAC;YACxB,IAAI,CAAC,UAAU,GAAG,CAAC,CAAC;YACpB,IAAI,CAAC,eAAe,GAAG,QAAQ,CAAC;YAChC,IAAI,CAAC,OAAO,GAAG,EAAE,CAAC;YAClB,IAAI,CAAC,WAAW,GAAG,EAAE,CAAC;YACtB,IAAI,CAAC,QAAQ,GAAG,EAAE,CAAC;YACnB,IAAI,CAAC,OAAO,GAAG,EAAE,CAAC;QACnB,CAAC;QAED,IAAI,WAAW;YACd,IAAI,OAAO,IAAI,CAAC,mBAAmB,KAAK,QAAQ,EAAE;gBACjD,OAAO,IAAI,CAAC,mBAAmB,CAAC;aAChC;YACD,OAAO,gBAAgB,EAAE,CAAC,CAAC,CAAC,GAAG,CAAC,CAAC,CAAC,EAAE,CAAC;QACtC,CAAC;QAED,IAAI,WAAW,CAAC,CAAS;YACxB,IAAI,CAAC,mBAAmB,GAAG,CAAC,CAAC;QAC9B,CAAC;QAED,IAAI,QAAQ;YACX,IAAI,OAAO,IAAI,CAAC,gBAAgB,KAAK,QAAQ,EAAE;gBAC9C,OAAO,IAAI,CAAC,gBAAgB,CAAC;aAC7B;YACD,OAAO,gBAAgB,EAAE,CAAC,CAAC,CAAC,QAAQ,CAAC,CAAC,CAAC,OAAO,CAAC;QAChD,CAAC;QAED,IAAI,QAAQ,CAAC,CAAS;YACrB,IAAI,CAAC,gBAAgB,GAAG,CAAC,CAAC;QAC3B,CAAC;QAaD,QAAQ,CACP,GAA8B,EAC9B,IAA8B,EAC9B,EAAsC;YAKtC,MAAM,IAAI,KAAK,CACd,yFAAyF,CACzF,CAAC;QACH,CAAC;QAED;;;;;WAKG;QACH,UAAU,CAAC,GAAkB,EAAE,KAAqB;YACnD,MAAM,IAAI,qBAAwB,KAAK,CAAE,CAAC;YAE1C,IAAI,OAAO,IAAI,CAAC,cAAc,KAAK,SAAS,EAAE;gBAC7C,IAAI,CAAC,cAAc,GAAG,gBAAgB,EAAE,CAAC;aACzC;YAED,IAAI,IAAI,CAAC,IAAI,IAAI,IAAI,EAAE;gBACtB,IAAI,CAAC,IAAI,GAAG,WAAW,CAAC;aACxB;YAED,IAAI,IAAI,CAAC,IAAI,IAAI,IAAI,EAAE;gBACtB,IAAI,CAAC,IAAI,GAAG,IAAI,CAAC,cAAc,CAAC,CAAC,CAAC,GAAG,CAAC,CAAC,CAAC,EAAE,CAAC;aAC3C;YAED,IAAI,IAAI,CAAC,QAAQ,IAAI,IAAI,EAAE;gBAC1B,IAAI,CAAC,QAAQ,GAAG,IAAI,CAAC,cAAc,CAAC,CAAC,CAAC,QAAQ,CAAC,CAAC,CAAC,OAAO,CAAC;aACzD;YAED,IAAI,IAAI,CAAC,IAAI,IAAI,IAAI,CAAC,IAAI,EAAE;gBAC3B,2DAA2D;gBAC3D,0DAA0D;gBAC1D,4DAA4D;gBAC5D,8CAA8C;gBAC9C,OAAO,IAAI,CAAC,IAAI,CAAC;aACjB;YAED,OAAO,IAAI,CAAC,KAAK,CAAC;YAClB,OAAO,IAAI,CAAC,QAAQ,CAAC;YACrB,OAAO,IAAI,CAAC,aAAa,CAAC;YAC1B,OAAO,IAAI,CAAC,WAAW,CAAC;YACxB,OAAO,IAAI,CAAC,gBAAgB,CAAC;YAE7B,kCAAkC;YAClC,2CAA2C;YAC3C,GAAG,CAAC,KAAK,GAAG,IAAI,CAAC;YACjB,GAAG,CAAC,eAAe,GAAG,KAAK,CAAC;YAE5B,IAAI,QAAQ,GAAG,KAAK,CAAC;YACrB,IAAI,SAAS,GAAyC,IAAI,CAAC;YAC3D,MAAM,SAAS,GAAG,IAAI,CAAC,OAAO,IAAI,IAAI,CAAC,OAAO,CAAC;YAE/C,MAAM,OAAO,GAAG,CAAC,GAA0B,EAAE,EAAE;gBAC9C,IAAI,GAAG,CAAC,SAAS;oBAAE,OAAO;gBAC1B,GAAG,CAAC,IAAI,CAAC,OAAO,EAAE,GAAG,CAAC,CAAC;gBACvB,yDAAyD;gBACzD,iEAAiE;gBACjE,GAAG,CAAC,SAAS,GAAG,IAAI,CAAC;YACtB,CAAC,CAAC;YAEF,MAAM,SAAS,GAAG,GAAG,EAAE;gBACtB,SAAS,GAAG,IAAI,CAAC;gBACjB,QAAQ,GAAG,IAAI,CAAC;gBAChB,MAAM,GAAG,GAA0B,IAAI,KAAK,CAC3C,sDAAsD,SAAS,IAAI,CACnE,CAAC;gBACF,GAAG,CAAC,IAAI,GAAG,UAAU,CAAC;gBACtB,OAAO,CAAC,GAAG,CAAC,CAAC;YACd,CAAC,CAAC;YAEF,MAAM,aAAa,GAAG,CAAC,GAA0B,EAAE,EAAE;gBACpD,IAAI,QAAQ;oBAAE,OAAO;gBACrB,IAAI,SAAS,KAAK,IAAI,EAAE;oBACvB,YAAY,CAAC,SAAS,CAAC,CAAC;oBACxB,SAAS,GAAG,IAAI,CAAC;iBACjB;gBACD,OAAO,CAAC,GAAG,CAAC,CAAC;YACd,CAAC,CAAC;YAEF,MAAM,QAAQ,GAAG,CAAC,MAA2B,EAAE,EAAE;gBAChD,IAAI,QAAQ;oBAAE,OAAO;gBACrB,IAAI,SAAS,IAAI,IAAI,EAAE;oBACtB,YAAY,CAAC,SAAS,CAAC,CAAC;oBACxB,SAAS,GAAG,IAAI,CAAC;iBACjB;gBAED,IAAI,OAAO,CAAC,MAAM,CAAC,EAAE;oBACpB,oDAAoD;oBACpD,wDAAwD;oBACxD,eAAe;oBACf,KAAK,CACJ,6CAA6C,EAC7C,MAAM,CAAC,WAAW,CAAC,IAAI,CACvB,CAAC;oBACD,MAA4B,CAAC,UAAU,CAAC,GAAG,EAAE,IAAI,CAAC,CAAC;oBACpD,OAAO;iBACP;gBAED,IAAI,MAAM,EAAE;oBACX,MAAM,CAAC,IAAI,CAAC,MAAM,EAAE,GAAG,EAAE;wBACxB,IAAI,CAAC,UAAU,CAAC,MAAoB,EAAE,IAAI,CAAC,CAAC;oBAC7C,CAAC,CAAC,CAAC;oBACH,GAAG,CAAC,QAAQ,CAAC,MAAoB,CAAC,CAAC;oBACnC,OAAO;iBACP;gBAED,MAAM,GAAG,GAAG,IAAI,KAAK,CACpB,qDAAqD,GAAG,CAAC,MAAM,IAAI,GAAG,CAAC,IAAI,IAAI,CAC/E,CAAC;gBACF,OAAO,CAAC,GAAG,CAAC,CAAC;YACd,CAAC,CAAC;YAEF,IAAI,OAAO,IAAI,CAAC,QAAQ,KAAK,UAAU,EAAE;gBACxC,OAAO,CAAC,IAAI,KAAK,CAAC,2BAA2B,CAAC,CAAC,CAAC;gBAChD,OAAO;aACP;YAED,IAAI,CAAC,IAAI,CAAC,mBAAmB,EAAE;gBAC9B,IAAI,IAAI,CAAC,QAAQ,CAAC,MAAM,IAAI,CAAC,EAAE;oBAC9B,KAAK,CAAC,gDAAgD,CAAC,CAAC;oBACxD,IAAI,CAAC,mBAAmB,GAAG,mBAAS,CAAC,IAAI,CAAC,QAAQ,CAAC,CAAC;iBACpD;qBAAM;oBACN,IAAI,CAAC,mBAAmB,GAAG,IAAI,CAAC,QAAQ,CAAC;iBACzC;aACD;YAED,IAAI,OAAO,SAAS,KAAK,QAAQ,IAAI,SAAS,GAAG,CAAC,EAAE;gBACnD,SAAS,GAAG,UAAU,CAAC,SAAS,EAAE,SAAS,CAAC,CAAC;aAC7C;YAED,IAAI,MAAM,IAAI,IAAI,IAAI,OA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\ No newline at end of file
diff --git a/server/node_modules/agent-base/dist/src/promisify.d.ts b/server/node_modules/agent-base/dist/src/promisify.d.ts
new file mode 100644
index 0000000..0268869
--- /dev/null
+++ b/server/node_modules/agent-base/dist/src/promisify.d.ts
@@ -0,0 +1,4 @@
+import { ClientRequest, RequestOptions, AgentCallbackCallback, AgentCallbackPromise } from './index';
+declare type LegacyCallback = (req: ClientRequest, opts: RequestOptions, fn: AgentCallbackCallback) => void;
+export default function promisify(fn: LegacyCallback): AgentCallbackPromise;
+export {};
diff --git a/server/node_modules/agent-base/dist/src/promisify.js b/server/node_modules/agent-base/dist/src/promisify.js
new file mode 100644
index 0000000..b2f6132
--- /dev/null
+++ b/server/node_modules/agent-base/dist/src/promisify.js
@@ -0,0 +1,18 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+function promisify(fn) {
+    return function (req, opts) {
+        return new Promise((resolve, reject) => {
+            fn.call(this, req, opts, (err, rtn) => {
+                if (err) {
+                    reject(err);
+                }
+                else {
+                    resolve(rtn);
+                }
+            });
+        });
+    };
+}
+exports.default = promisify;
+//# sourceMappingURL=promisify.js.map
\ No newline at end of file
diff --git a/server/node_modules/agent-base/dist/src/promisify.js.map b/server/node_modules/agent-base/dist/src/promisify.js.map
new file mode 100644
index 0000000..4bff9bf
--- /dev/null
+++ b/server/node_modules/agent-base/dist/src/promisify.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"promisify.js","sourceRoot":"","sources":["../../src/promisify.ts"],"names":[],"mappings":";;AAeA,SAAwB,SAAS,CAAC,EAAkB;IACnD,OAAO,UAAsB,GAAkB,EAAE,IAAoB;QACpE,OAAO,IAAI,OAAO,CAAC,CAAC,OAAO,EAAE,MAAM,EAAE,EAAE;YACtC,EAAE,CAAC,IAAI,CACN,IAAI,EACJ,GAAG,EACH,IAAI,EACJ,CAAC,GAA6B,EAAE,GAAyB,EAAE,EAAE;gBAC5D,IAAI,GAAG,EAAE;oBACR,MAAM,CAAC,GAAG,CAAC,CAAC;iBACZ;qBAAM;oBACN,OAAO,CAAC,GAAG,CAAC,CAAC;iBACb;YACF,CAAC,CACD,CAAC;QACH,CAAC,CAAC,CAAC;IACJ,CAAC,CAAC;AACH,CAAC;AAjBD,4BAiBC"}
\ No newline at end of file
diff --git a/server/node_modules/agent-base/node_modules/debug/LICENSE b/server/node_modules/agent-base/node_modules/debug/LICENSE
new file mode 100644
index 0000000..1a9820e
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/debug/LICENSE
@@ -0,0 +1,20 @@
+(The MIT License)
+
+Copyright (c) 2014-2017 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2018-2021 Josh Junon
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+and associated documentation files (the 'Software'), to deal in the Software without restriction,
+including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial
+portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
+LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/agent-base/node_modules/debug/README.md b/server/node_modules/agent-base/node_modules/debug/README.md
new file mode 100644
index 0000000..9ebdfbf
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/debug/README.md
@@ -0,0 +1,481 @@
+# debug
+[![OpenCollective](https://opencollective.com/debug/backers/badge.svg)](#backers)
+[![OpenCollective](https://opencollective.com/debug/sponsors/badge.svg)](#sponsors)
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091486-fa38524c-7c37-11e7-895f-e7ec8e1039b6.png">
+
+A tiny JavaScript debugging utility modelled after Node.js core's debugging
+technique. Works in Node.js and web browsers.
+
+## Installation
+
+```bash
+$ npm install debug
+```
+
+## Usage
+
+`debug` exposes a function; simply pass this function the name of your module, and it will return a decorated version of `console.error` for you to pass debug statements to. This will allow you to toggle the debug output for different parts of your module as well as the module as a whole.
+
+Example [_app.js_](./examples/node/app.js):
+
+```js
+var debug = require('debug')('http')
+  , http = require('http')
+  , name = 'My App';
+
+// fake app
+
+debug('booting %o', name);
+
+http.createServer(function(req, res){
+  debug(req.method + ' ' + req.url);
+  res.end('hello\n');
+}).listen(3000, function(){
+  debug('listening');
+});
+
+// fake worker of some kind
+
+require('./worker');
+```
+
+Example [_worker.js_](./examples/node/worker.js):
+
+```js
+var a = require('debug')('worker:a')
+  , b = require('debug')('worker:b');
+
+function work() {
+  a('doing lots of uninteresting work');
+  setTimeout(work, Math.random() * 1000);
+}
+
+work();
+
+function workb() {
+  b('doing some work');
+  setTimeout(workb, Math.random() * 2000);
+}
+
+workb();
+```
+
+The `DEBUG` environment variable is then used to enable these based on space or
+comma-delimited names.
+
+Here are some examples:
+
+<img width="647" alt="screen shot 2017-08-08 at 12 53 04 pm" src="https://user-images.githubusercontent.com/71256/29091703-a6302cdc-7c38-11e7-8304-7c0b3bc600cd.png">
+<img width="647" alt="screen shot 2017-08-08 at 12 53 38 pm" src="https://user-images.githubusercontent.com/71256/29091700-a62a6888-7c38-11e7-800b-db911291ca2b.png">
+<img width="647" alt="screen shot 2017-08-08 at 12 53 25 pm" src="https://user-images.githubusercontent.com/71256/29091701-a62ea114-7c38-11e7-826a-2692bedca740.png">
+
+#### Windows command prompt notes
+
+##### CMD
+
+On Windows the environment variable is set using the `set` command.
+
+```cmd
+set DEBUG=*,-not_this
+```
+
+Example:
+
+```cmd
+set DEBUG=* & node app.js
+```
+
+##### PowerShell (VS Code default)
+
+PowerShell uses different syntax to set environment variables.
+
+```cmd
+$env:DEBUG = "*,-not_this"
+```
+
+Example:
+
+```cmd
+$env:DEBUG='app';node app.js
+```
+
+Then, run the program to be debugged as usual.
+
+npm script example:
+```js
+  "windowsDebug": "@powershell -Command $env:DEBUG='*';node app.js",
+```
+
+## Namespace Colors
+
+Every debug instance has a color generated for it based on its namespace name.
+This helps when visually parsing the debug output to identify which debug instance
+a debug line belongs to.
+
+#### Node.js
+
+In Node.js, colors are enabled when stderr is a TTY. You also _should_ install
+the [`supports-color`](https://npmjs.org/supports-color) module alongside debug,
+otherwise debug will only use a small handful of basic colors.
+
+<img width="521" src="https://user-images.githubusercontent.com/71256/29092181-47f6a9e6-7c3a-11e7-9a14-1928d8a711cd.png">
+
+#### Web Browser
+
+Colors are also enabled on "Web Inspectors" that understand the `%c` formatting
+option. These are WebKit web inspectors, Firefox ([since version
+31](https://hacks.mozilla.org/2014/05/editable-box-model-multiple-selection-sublime-text-keys-much-more-firefox-developer-tools-episode-31/))
+and the Firebug plugin for Firefox (any version).
+
+<img width="524" src="https://user-images.githubusercontent.com/71256/29092033-b65f9f2e-7c39-11e7-8e32-f6f0d8e865c1.png">
+
+
+## Millisecond diff
+
+When actively developing an application it can be useful to see when the time spent between one `debug()` call and the next. Suppose for example you invoke `debug()` before requesting a resource, and after as well, the "+NNNms" will show you how much time was spent between calls.
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091486-fa38524c-7c37-11e7-895f-e7ec8e1039b6.png">
+
+When stdout is not a TTY, `Date#toISOString()` is used, making it more useful for logging the debug information as shown below:
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091956-6bd78372-7c39-11e7-8c55-c948396d6edd.png">
+
+
+## Conventions
+
+If you're using this in one or more of your libraries, you _should_ use the name of your library so that developers may toggle debugging as desired without guessing names. If you have more than one debuggers you _should_ prefix them with your library name and use ":" to separate features. For example "bodyParser" from Connect would then be "connect:bodyParser".  If you append a "*" to the end of your name, it will always be enabled regardless of the setting of the DEBUG environment variable.  You can then use it for normal output as well as debug output.
+
+## Wildcards
+
+The `*` character may be used as a wildcard. Suppose for example your library has
+debuggers named "connect:bodyParser", "connect:compress", "connect:session",
+instead of listing all three with
+`DEBUG=connect:bodyParser,connect:compress,connect:session`, you may simply do
+`DEBUG=connect:*`, or to run everything using this module simply use `DEBUG=*`.
+
+You can also exclude specific debuggers by prefixing them with a "-" character.
+For example, `DEBUG=*,-connect:*` would include all debuggers except those
+starting with "connect:".
+
+## Environment Variables
+
+When running through Node.js, you can set a few environment variables that will
+change the behavior of the debug logging:
+
+| Name      | Purpose                                         |
+|-----------|-------------------------------------------------|
+| `DEBUG`   | Enables/disables specific debugging namespaces. |
+| `DEBUG_HIDE_DATE` | Hide date from debug output (non-TTY).  |
+| `DEBUG_COLORS`| Whether or not to use colors in the debug output. |
+| `DEBUG_DEPTH` | Object inspection depth.                    |
+| `DEBUG_SHOW_HIDDEN` | Shows hidden properties on inspected objects. |
+
+
+__Note:__ The environment variables beginning with `DEBUG_` end up being
+converted into an Options object that gets used with `%o`/`%O` formatters.
+See the Node.js documentation for
+[`util.inspect()`](https://nodejs.org/api/util.html#util_util_inspect_object_options)
+for the complete list.
+
+## Formatters
+
+Debug uses [printf-style](https://wikipedia.org/wiki/Printf_format_string) formatting.
+Below are the officially supported formatters:
+
+| Formatter | Representation |
+|-----------|----------------|
+| `%O`      | Pretty-print an Object on multiple lines. |
+| `%o`      | Pretty-print an Object all on a single line. |
+| `%s`      | String. |
+| `%d`      | Number (both integer and float). |
+| `%j`      | JSON. Replaced with the string '[Circular]' if the argument contains circular references. |
+| `%%`      | Single percent sign ('%'). This does not consume an argument. |
+
+
+### Custom formatters
+
+You can add custom formatters by extending the `debug.formatters` object.
+For example, if you wanted to add support for rendering a Buffer as hex with
+`%h`, you could do something like:
+
+```js
+const createDebug = require('debug')
+createDebug.formatters.h = (v) => {
+  return v.toString('hex')
+}
+
+// …elsewhere
+const debug = createDebug('foo')
+debug('this is hex: %h', new Buffer('hello world'))
+//   foo this is hex: 68656c6c6f20776f726c6421 +0ms
+```
+
+
+## Browser Support
+
+You can build a browser-ready script using [browserify](https://github.com/substack/node-browserify),
+or just use the [browserify-as-a-service](https://wzrd.in/) [build](https://wzrd.in/standalone/debug@latest),
+if you don't want to build it yourself.
+
+Debug's enable state is currently persisted by `localStorage`.
+Consider the situation shown below where you have `worker:a` and `worker:b`,
+and wish to debug both. You can enable this using `localStorage.debug`:
+
+```js
+localStorage.debug = 'worker:*'
+```
+
+And then refresh the page.
+
+```js
+a = debug('worker:a');
+b = debug('worker:b');
+
+setInterval(function(){
+  a('doing some work');
+}, 1000);
+
+setInterval(function(){
+  b('doing some work');
+}, 1200);
+```
+
+In Chromium-based web browsers (e.g. Brave, Chrome, and Electron), the JavaScript console will—by default—only show messages logged by `debug` if the "Verbose" log level is _enabled_.
+
+<img width="647" src="https://user-images.githubusercontent.com/7143133/152083257-29034707-c42c-4959-8add-3cee850e6fcf.png">
+
+## Output streams
+
+  By default `debug` will log to stderr, however this can be configured per-namespace by overriding the `log` method:
+
+Example [_stdout.js_](./examples/node/stdout.js):
+
+```js
+var debug = require('debug');
+var error = debug('app:error');
+
+// by default stderr is used
+error('goes to stderr!');
+
+var log = debug('app:log');
+// set this namespace to log via console.log
+log.log = console.log.bind(console); // don't forget to bind to console!
+log('goes to stdout');
+error('still goes to stderr!');
+
+// set all output to go via console.info
+// overrides all per-namespace log settings
+debug.log = console.info.bind(console);
+error('now goes to stdout via console.info');
+log('still goes to stdout, but via console.info now');
+```
+
+## Extend
+You can simply extend debugger 
+```js
+const log = require('debug')('auth');
+
+//creates new debug instance with extended namespace
+const logSign = log.extend('sign');
+const logLogin = log.extend('login');
+
+log('hello'); // auth hello
+logSign('hello'); //auth:sign hello
+logLogin('hello'); //auth:login hello
+```
+
+## Set dynamically
+
+You can also enable debug dynamically by calling the `enable()` method :
+
+```js
+let debug = require('debug');
+
+console.log(1, debug.enabled('test'));
+
+debug.enable('test');
+console.log(2, debug.enabled('test'));
+
+debug.disable();
+console.log(3, debug.enabled('test'));
+
+```
+
+print :   
+```
+1 false
+2 true
+3 false
+```
+
+Usage :  
+`enable(namespaces)`  
+`namespaces` can include modes separated by a colon and wildcards.
+   
+Note that calling `enable()` completely overrides previously set DEBUG variable : 
+
+```
+$ DEBUG=foo node -e 'var dbg = require("debug"); dbg.enable("bar"); console.log(dbg.enabled("foo"))'
+=> false
+```
+
+`disable()`
+
+Will disable all namespaces. The functions returns the namespaces currently
+enabled (and skipped). This can be useful if you want to disable debugging
+temporarily without knowing what was enabled to begin with.
+
+For example:
+
+```js
+let debug = require('debug');
+debug.enable('foo:*,-foo:bar');
+let namespaces = debug.disable();
+debug.enable(namespaces);
+```
+
+Note: There is no guarantee that the string will be identical to the initial
+enable string, but semantically they will be identical.
+
+## Checking whether a debug target is enabled
+
+After you've created a debug instance, you can determine whether or not it is
+enabled by checking the `enabled` property:
+
+```javascript
+const debug = require('debug')('http');
+
+if (debug.enabled) {
+  // do stuff...
+}
+```
+
+You can also manually toggle this property to force the debug instance to be
+enabled or disabled.
+
+## Usage in child processes
+
+Due to the way `debug` detects if the output is a TTY or not, colors are not shown in child processes when `stderr` is piped. A solution is to pass the `DEBUG_COLORS=1` environment variable to the child process.  
+For example:
+
+```javascript
+worker = fork(WORKER_WRAP_PATH, [workerPath], {
+  stdio: [
+    /* stdin: */ 0,
+    /* stdout: */ 'pipe',
+    /* stderr: */ 'pipe',
+    'ipc',
+  ],
+  env: Object.assign({}, process.env, {
+    DEBUG_COLORS: 1 // without this settings, colors won't be shown
+  }),
+});
+
+worker.stderr.pipe(process.stderr, { end: false });
+```
+
+
+## Authors
+
+ - TJ Holowaychuk
+ - Nathan Rajlich
+ - Andrew Rhyne
+ - Josh Junon
+
+## Backers
+
+Support us with a monthly donation and help us continue our activities. [[Become a backer](https://opencollective.com/debug#backer)]
+
+<a href="https://opencollective.com/debug/backer/0/website" target="_blank"><img src="https://opencollective.com/debug/backer/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/1/website" target="_blank"><img src="https://opencollective.com/debug/backer/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/2/website" target="_blank"><img src="https://opencollective.com/debug/backer/2/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/3/website" target="_blank"><img src="https://opencollective.com/debug/backer/3/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/4/website" target="_blank"><img src="https://opencollective.com/debug/backer/4/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/5/website" target="_blank"><img src="https://opencollective.com/debug/backer/5/avatar.svg"></a>
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+<a href="https://opencollective.com/debug/backer/14/website" target="_blank"><img src="https://opencollective.com/debug/backer/14/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/15/website" target="_blank"><img src="https://opencollective.com/debug/backer/15/avatar.svg"></a>
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+<a href="https://opencollective.com/debug/backer/18/website" target="_blank"><img src="https://opencollective.com/debug/backer/18/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/19/website" target="_blank"><img src="https://opencollective.com/debug/backer/19/avatar.svg"></a>
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+<a href="https://opencollective.com/debug/backer/22/website" target="_blank"><img src="https://opencollective.com/debug/backer/22/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/23/website" target="_blank"><img src="https://opencollective.com/debug/backer/23/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/24/website" target="_blank"><img src="https://opencollective.com/debug/backer/24/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/25/website" target="_blank"><img src="https://opencollective.com/debug/backer/25/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/26/website" target="_blank"><img src="https://opencollective.com/debug/backer/26/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/27/website" target="_blank"><img src="https://opencollective.com/debug/backer/27/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/28/website" target="_blank"><img src="https://opencollective.com/debug/backer/28/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/29/website" target="_blank"><img src="https://opencollective.com/debug/backer/29/avatar.svg"></a>
+
+
+## Sponsors
+
+Become a sponsor and get your logo on our README on Github with a link to your site. [[Become a sponsor](https://opencollective.com/debug#sponsor)]
+
+<a href="https://opencollective.com/debug/sponsor/0/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/1/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/2/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/2/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/3/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/3/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/4/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/4/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/5/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/5/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/6/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/6/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/7/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/7/avatar.svg"></a>
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+<a href="https://opencollective.com/debug/sponsor/13/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/13/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/14/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/14/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/15/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/15/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/16/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/16/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/17/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/17/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/18/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/18/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/19/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/19/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/20/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/20/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/21/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/21/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/22/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/22/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/23/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/23/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/24/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/24/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/25/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/25/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/26/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/26/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/27/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/27/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/28/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/28/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/29/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/29/avatar.svg"></a>
+
+## License
+
+(The MIT License)
+
+Copyright (c) 2014-2017 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2018-2021 Josh Junon
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/agent-base/node_modules/debug/package.json b/server/node_modules/agent-base/node_modules/debug/package.json
new file mode 100644
index 0000000..ee8abb5
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/debug/package.json
@@ -0,0 +1,64 @@
+{
+  "name": "debug",
+  "version": "4.4.3",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/debug-js/debug.git"
+  },
+  "description": "Lightweight debugging utility for Node.js and the browser",
+  "keywords": [
+    "debug",
+    "log",
+    "debugger"
+  ],
+  "files": [
+    "src",
+    "LICENSE",
+    "README.md"
+  ],
+  "author": "Josh Junon (https://github.com/qix-)",
+  "contributors": [
+    "TJ Holowaychuk <tj@vision-media.ca>",
+    "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io)",
+    "Andrew Rhyne <rhyneandrew@gmail.com>"
+  ],
+  "license": "MIT",
+  "scripts": {
+    "lint": "xo",
+    "test": "npm run test:node && npm run test:browser && npm run lint",
+    "test:node": "mocha test.js test.node.js",
+    "test:browser": "karma start --single-run",
+    "test:coverage": "cat ./coverage/lcov.info | coveralls"
+  },
+  "dependencies": {
+    "ms": "^2.1.3"
+  },
+  "devDependencies": {
+    "brfs": "^2.0.1",
+    "browserify": "^16.2.3",
+    "coveralls": "^3.0.2",
+    "karma": "^3.1.4",
+    "karma-browserify": "^6.0.0",
+    "karma-chrome-launcher": "^2.2.0",
+    "karma-mocha": "^1.3.0",
+    "mocha": "^5.2.0",
+    "mocha-lcov-reporter": "^1.2.0",
+    "sinon": "^14.0.0",
+    "xo": "^0.23.0"
+  },
+  "peerDependenciesMeta": {
+    "supports-color": {
+      "optional": true
+    }
+  },
+  "main": "./src/index.js",
+  "browser": "./src/browser.js",
+  "engines": {
+    "node": ">=6.0"
+  },
+  "xo": {
+    "rules": {
+      "import/extensions": "off"
+    }
+  }
+}
diff --git a/server/node_modules/agent-base/node_modules/debug/src/browser.js b/server/node_modules/agent-base/node_modules/debug/src/browser.js
new file mode 100644
index 0000000..5993451
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/debug/src/browser.js
@@ -0,0 +1,272 @@
+/* eslint-env browser */
+
+/**
+ * This is the web browser implementation of `debug()`.
+ */
+
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+exports.storage = localstorage();
+exports.destroy = (() => {
+	let warned = false;
+
+	return () => {
+		if (!warned) {
+			warned = true;
+			console.warn('Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.');
+		}
+	};
+})();
+
+/**
+ * Colors.
+ */
+
+exports.colors = [
+	'#0000CC',
+	'#0000FF',
+	'#0033CC',
+	'#0033FF',
+	'#0066CC',
+	'#0066FF',
+	'#0099CC',
+	'#0099FF',
+	'#00CC00',
+	'#00CC33',
+	'#00CC66',
+	'#00CC99',
+	'#00CCCC',
+	'#00CCFF',
+	'#3300CC',
+	'#3300FF',
+	'#3333CC',
+	'#3333FF',
+	'#3366CC',
+	'#3366FF',
+	'#3399CC',
+	'#3399FF',
+	'#33CC00',
+	'#33CC33',
+	'#33CC66',
+	'#33CC99',
+	'#33CCCC',
+	'#33CCFF',
+	'#6600CC',
+	'#6600FF',
+	'#6633CC',
+	'#6633FF',
+	'#66CC00',
+	'#66CC33',
+	'#9900CC',
+	'#9900FF',
+	'#9933CC',
+	'#9933FF',
+	'#99CC00',
+	'#99CC33',
+	'#CC0000',
+	'#CC0033',
+	'#CC0066',
+	'#CC0099',
+	'#CC00CC',
+	'#CC00FF',
+	'#CC3300',
+	'#CC3333',
+	'#CC3366',
+	'#CC3399',
+	'#CC33CC',
+	'#CC33FF',
+	'#CC6600',
+	'#CC6633',
+	'#CC9900',
+	'#CC9933',
+	'#CCCC00',
+	'#CCCC33',
+	'#FF0000',
+	'#FF0033',
+	'#FF0066',
+	'#FF0099',
+	'#FF00CC',
+	'#FF00FF',
+	'#FF3300',
+	'#FF3333',
+	'#FF3366',
+	'#FF3399',
+	'#FF33CC',
+	'#FF33FF',
+	'#FF6600',
+	'#FF6633',
+	'#FF9900',
+	'#FF9933',
+	'#FFCC00',
+	'#FFCC33'
+];
+
+/**
+ * Currently only WebKit-based Web Inspectors, Firefox >= v31,
+ * and the Firebug extension (any Firefox version) are known
+ * to support "%c" CSS customizations.
+ *
+ * TODO: add a `localStorage` variable to explicitly enable/disable colors
+ */
+
+// eslint-disable-next-line complexity
+function useColors() {
+	// NB: In an Electron preload script, document will be defined but not fully
+	// initialized. Since we know we're in Chrome, we'll just detect this case
+	// explicitly
+	if (typeof window !== 'undefined' && window.process && (window.process.type === 'renderer' || window.process.__nwjs)) {
+		return true;
+	}
+
+	// Internet Explorer and Edge do not support colors.
+	if (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/(edge|trident)\/(\d+)/)) {
+		return false;
+	}
+
+	let m;
+
+	// Is webkit? http://stackoverflow.com/a/16459606/376773
+	// document is undefined in react-native: https://github.com/facebook/react-native/pull/1632
+	// eslint-disable-next-line no-return-assign
+	return (typeof document !== 'undefined' && document.documentElement && document.documentElement.style && document.documentElement.style.WebkitAppearance) ||
+		// Is firebug? http://stackoverflow.com/a/398120/376773
+		(typeof window !== 'undefined' && window.console && (window.console.firebug || (window.console.exception && window.console.table))) ||
+		// Is firefox >= v31?
+		// https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
+		(typeof navigator !== 'undefined' && navigator.userAgent && (m = navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/)) && parseInt(m[1], 10) >= 31) ||
+		// Double check webkit in userAgent just in case we are in a worker
+		(typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/applewebkit\/(\d+)/));
+}
+
+/**
+ * Colorize log arguments if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+	args[0] = (this.useColors ? '%c' : '') +
+		this.namespace +
+		(this.useColors ? ' %c' : ' ') +
+		args[0] +
+		(this.useColors ? '%c ' : ' ') +
+		'+' + module.exports.humanize(this.diff);
+
+	if (!this.useColors) {
+		return;
+	}
+
+	const c = 'color: ' + this.color;
+	args.splice(1, 0, c, 'color: inherit');
+
+	// The final "%c" is somewhat tricky, because there could be other
+	// arguments passed either before or after the %c, so we need to
+	// figure out the correct index to insert the CSS into
+	let index = 0;
+	let lastC = 0;
+	args[0].replace(/%[a-zA-Z%]/g, match => {
+		if (match === '%%') {
+			return;
+		}
+		index++;
+		if (match === '%c') {
+			// We only are interested in the *last* %c
+			// (the user may have provided their own)
+			lastC = index;
+		}
+	});
+
+	args.splice(lastC, 0, c);
+}
+
+/**
+ * Invokes `console.debug()` when available.
+ * No-op when `console.debug` is not a "function".
+ * If `console.debug` is not available, falls back
+ * to `console.log`.
+ *
+ * @api public
+ */
+exports.log = console.debug || console.log || (() => {});
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+function save(namespaces) {
+	try {
+		if (namespaces) {
+			exports.storage.setItem('debug', namespaces);
+		} else {
+			exports.storage.removeItem('debug');
+		}
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+function load() {
+	let r;
+	try {
+		r = exports.storage.getItem('debug') || exports.storage.getItem('DEBUG') ;
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+
+	// If debug isn't set in LS, and we're in Electron, try to load $DEBUG
+	if (!r && typeof process !== 'undefined' && 'env' in process) {
+		r = process.env.DEBUG;
+	}
+
+	return r;
+}
+
+/**
+ * Localstorage attempts to return the localstorage.
+ *
+ * This is necessary because safari throws
+ * when a user disables cookies/localstorage
+ * and you attempt to access it.
+ *
+ * @return {LocalStorage}
+ * @api private
+ */
+
+function localstorage() {
+	try {
+		// TVMLKit (Apple TV JS Runtime) does not have a window object, just localStorage in the global context
+		// The Browser also has localStorage in the global context.
+		return localStorage;
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+}
+
+module.exports = require('./common')(exports);
+
+const {formatters} = module.exports;
+
+/**
+ * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
+ */
+
+formatters.j = function (v) {
+	try {
+		return JSON.stringify(v);
+	} catch (error) {
+		return '[UnexpectedJSONParseError]: ' + error.message;
+	}
+};
diff --git a/server/node_modules/agent-base/node_modules/debug/src/common.js b/server/node_modules/agent-base/node_modules/debug/src/common.js
new file mode 100644
index 0000000..141cb57
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/debug/src/common.js
@@ -0,0 +1,292 @@
+
+/**
+ * This is the common logic for both the Node.js and web browser
+ * implementations of `debug()`.
+ */
+
+function setup(env) {
+	createDebug.debug = createDebug;
+	createDebug.default = createDebug;
+	createDebug.coerce = coerce;
+	createDebug.disable = disable;
+	createDebug.enable = enable;
+	createDebug.enabled = enabled;
+	createDebug.humanize = require('ms');
+	createDebug.destroy = destroy;
+
+	Object.keys(env).forEach(key => {
+		createDebug[key] = env[key];
+	});
+
+	/**
+	* The currently active debug mode names, and names to skip.
+	*/
+
+	createDebug.names = [];
+	createDebug.skips = [];
+
+	/**
+	* Map of special "%n" handling functions, for the debug "format" argument.
+	*
+	* Valid key names are a single, lower or upper-case letter, i.e. "n" and "N".
+	*/
+	createDebug.formatters = {};
+
+	/**
+	* Selects a color for a debug namespace
+	* @param {String} namespace The namespace string for the debug instance to be colored
+	* @return {Number|String} An ANSI color code for the given namespace
+	* @api private
+	*/
+	function selectColor(namespace) {
+		let hash = 0;
+
+		for (let i = 0; i < namespace.length; i++) {
+			hash = ((hash << 5) - hash) + namespace.charCodeAt(i);
+			hash |= 0; // Convert to 32bit integer
+		}
+
+		return createDebug.colors[Math.abs(hash) % createDebug.colors.length];
+	}
+	createDebug.selectColor = selectColor;
+
+	/**
+	* Create a debugger with the given `namespace`.
+	*
+	* @param {String} namespace
+	* @return {Function}
+	* @api public
+	*/
+	function createDebug(namespace) {
+		let prevTime;
+		let enableOverride = null;
+		let namespacesCache;
+		let enabledCache;
+
+		function debug(...args) {
+			// Disabled?
+			if (!debug.enabled) {
+				return;
+			}
+
+			const self = debug;
+
+			// Set `diff` timestamp
+			const curr = Number(new Date());
+			const ms = curr - (prevTime || curr);
+			self.diff = ms;
+			self.prev = prevTime;
+			self.curr = curr;
+			prevTime = curr;
+
+			args[0] = createDebug.coerce(args[0]);
+
+			if (typeof args[0] !== 'string') {
+				// Anything else let's inspect with %O
+				args.unshift('%O');
+			}
+
+			// Apply any `formatters` transformations
+			let index = 0;
+			args[0] = args[0].replace(/%([a-zA-Z%])/g, (match, format) => {
+				// If we encounter an escaped % then don't increase the array index
+				if (match === '%%') {
+					return '%';
+				}
+				index++;
+				const formatter = createDebug.formatters[format];
+				if (typeof formatter === 'function') {
+					const val = args[index];
+					match = formatter.call(self, val);
+
+					// Now we need to remove `args[index]` since it's inlined in the `format`
+					args.splice(index, 1);
+					index--;
+				}
+				return match;
+			});
+
+			// Apply env-specific formatting (colors, etc.)
+			createDebug.formatArgs.call(self, args);
+
+			const logFn = self.log || createDebug.log;
+			logFn.apply(self, args);
+		}
+
+		debug.namespace = namespace;
+		debug.useColors = createDebug.useColors();
+		debug.color = createDebug.selectColor(namespace);
+		debug.extend = extend;
+		debug.destroy = createDebug.destroy; // XXX Temporary. Will be removed in the next major release.
+
+		Object.defineProperty(debug, 'enabled', {
+			enumerable: true,
+			configurable: false,
+			get: () => {
+				if (enableOverride !== null) {
+					return enableOverride;
+				}
+				if (namespacesCache !== createDebug.namespaces) {
+					namespacesCache = createDebug.namespaces;
+					enabledCache = createDebug.enabled(namespace);
+				}
+
+				return enabledCache;
+			},
+			set: v => {
+				enableOverride = v;
+			}
+		});
+
+		// Env-specific initialization logic for debug instances
+		if (typeof createDebug.init === 'function') {
+			createDebug.init(debug);
+		}
+
+		return debug;
+	}
+
+	function extend(namespace, delimiter) {
+		const newDebug = createDebug(this.namespace + (typeof delimiter === 'undefined' ? ':' : delimiter) + namespace);
+		newDebug.log = this.log;
+		return newDebug;
+	}
+
+	/**
+	* Enables a debug mode by namespaces. This can include modes
+	* separated by a colon and wildcards.
+	*
+	* @param {String} namespaces
+	* @api public
+	*/
+	function enable(namespaces) {
+		createDebug.save(namespaces);
+		createDebug.namespaces = namespaces;
+
+		createDebug.names = [];
+		createDebug.skips = [];
+
+		const split = (typeof namespaces === 'string' ? namespaces : '')
+			.trim()
+			.replace(/\s+/g, ',')
+			.split(',')
+			.filter(Boolean);
+
+		for (const ns of split) {
+			if (ns[0] === '-') {
+				createDebug.skips.push(ns.slice(1));
+			} else {
+				createDebug.names.push(ns);
+			}
+		}
+	}
+
+	/**
+	 * Checks if the given string matches a namespace template, honoring
+	 * asterisks as wildcards.
+	 *
+	 * @param {String} search
+	 * @param {String} template
+	 * @return {Boolean}
+	 */
+	function matchesTemplate(search, template) {
+		let searchIndex = 0;
+		let templateIndex = 0;
+		let starIndex = -1;
+		let matchIndex = 0;
+
+		while (searchIndex < search.length) {
+			if (templateIndex < template.length && (template[templateIndex] === search[searchIndex] || template[templateIndex] === '*')) {
+				// Match character or proceed with wildcard
+				if (template[templateIndex] === '*') {
+					starIndex = templateIndex;
+					matchIndex = searchIndex;
+					templateIndex++; // Skip the '*'
+				} else {
+					searchIndex++;
+					templateIndex++;
+				}
+			} else if (starIndex !== -1) { // eslint-disable-line no-negated-condition
+				// Backtrack to the last '*' and try to match more characters
+				templateIndex = starIndex + 1;
+				matchIndex++;
+				searchIndex = matchIndex;
+			} else {
+				return false; // No match
+			}
+		}
+
+		// Handle trailing '*' in template
+		while (templateIndex < template.length && template[templateIndex] === '*') {
+			templateIndex++;
+		}
+
+		return templateIndex === template.length;
+	}
+
+	/**
+	* Disable debug output.
+	*
+	* @return {String} namespaces
+	* @api public
+	*/
+	function disable() {
+		const namespaces = [
+			...createDebug.names,
+			...createDebug.skips.map(namespace => '-' + namespace)
+		].join(',');
+		createDebug.enable('');
+		return namespaces;
+	}
+
+	/**
+	* Returns true if the given mode name is enabled, false otherwise.
+	*
+	* @param {String} name
+	* @return {Boolean}
+	* @api public
+	*/
+	function enabled(name) {
+		for (const skip of createDebug.skips) {
+			if (matchesTemplate(name, skip)) {
+				return false;
+			}
+		}
+
+		for (const ns of createDebug.names) {
+			if (matchesTemplate(name, ns)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	* Coerce `val`.
+	*
+	* @param {Mixed} val
+	* @return {Mixed}
+	* @api private
+	*/
+	function coerce(val) {
+		if (val instanceof Error) {
+			return val.stack || val.message;
+		}
+		return val;
+	}
+
+	/**
+	* XXX DO NOT USE. This is a temporary stub function.
+	* XXX It WILL be removed in the next major release.
+	*/
+	function destroy() {
+		console.warn('Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.');
+	}
+
+	createDebug.enable(createDebug.load());
+
+	return createDebug;
+}
+
+module.exports = setup;
diff --git a/server/node_modules/agent-base/node_modules/debug/src/index.js b/server/node_modules/agent-base/node_modules/debug/src/index.js
new file mode 100644
index 0000000..bf4c57f
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/debug/src/index.js
@@ -0,0 +1,10 @@
+/**
+ * Detect Electron renderer / nwjs process, which is node, but we should
+ * treat as a browser.
+ */
+
+if (typeof process === 'undefined' || process.type === 'renderer' || process.browser === true || process.__nwjs) {
+	module.exports = require('./browser.js');
+} else {
+	module.exports = require('./node.js');
+}
diff --git a/server/node_modules/agent-base/node_modules/debug/src/node.js b/server/node_modules/agent-base/node_modules/debug/src/node.js
new file mode 100644
index 0000000..715560a
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/debug/src/node.js
@@ -0,0 +1,263 @@
+/**
+ * Module dependencies.
+ */
+
+const tty = require('tty');
+const util = require('util');
+
+/**
+ * This is the Node.js implementation of `debug()`.
+ */
+
+exports.init = init;
+exports.log = log;
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+exports.destroy = util.deprecate(
+	() => {},
+	'Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.'
+);
+
+/**
+ * Colors.
+ */
+
+exports.colors = [6, 2, 3, 4, 5, 1];
+
+try {
+	// Optional dependency (as in, doesn't need to be installed, NOT like optionalDependencies in package.json)
+	// eslint-disable-next-line import/no-extraneous-dependencies
+	const supportsColor = require('supports-color');
+
+	if (supportsColor && (supportsColor.stderr || supportsColor).level >= 2) {
+		exports.colors = [
+			20,
+			21,
+			26,
+			27,
+			32,
+			33,
+			38,
+			39,
+			40,
+			41,
+			42,
+			43,
+			44,
+			45,
+			56,
+			57,
+			62,
+			63,
+			68,
+			69,
+			74,
+			75,
+			76,
+			77,
+			78,
+			79,
+			80,
+			81,
+			92,
+			93,
+			98,
+			99,
+			112,
+			113,
+			128,
+			129,
+			134,
+			135,
+			148,
+			149,
+			160,
+			161,
+			162,
+			163,
+			164,
+			165,
+			166,
+			167,
+			168,
+			169,
+			170,
+			171,
+			172,
+			173,
+			178,
+			179,
+			184,
+			185,
+			196,
+			197,
+			198,
+			199,
+			200,
+			201,
+			202,
+			203,
+			204,
+			205,
+			206,
+			207,
+			208,
+			209,
+			214,
+			215,
+			220,
+			221
+		];
+	}
+} catch (error) {
+	// Swallow - we only care if `supports-color` is available; it doesn't have to be.
+}
+
+/**
+ * Build up the default `inspectOpts` object from the environment variables.
+ *
+ *   $ DEBUG_COLORS=no DEBUG_DEPTH=10 DEBUG_SHOW_HIDDEN=enabled node script.js
+ */
+
+exports.inspectOpts = Object.keys(process.env).filter(key => {
+	return /^debug_/i.test(key);
+}).reduce((obj, key) => {
+	// Camel-case
+	const prop = key
+		.substring(6)
+		.toLowerCase()
+		.replace(/_([a-z])/g, (_, k) => {
+			return k.toUpperCase();
+		});
+
+	// Coerce string value into JS value
+	let val = process.env[key];
+	if (/^(yes|on|true|enabled)$/i.test(val)) {
+		val = true;
+	} else if (/^(no|off|false|disabled)$/i.test(val)) {
+		val = false;
+	} else if (val === 'null') {
+		val = null;
+	} else {
+		val = Number(val);
+	}
+
+	obj[prop] = val;
+	return obj;
+}, {});
+
+/**
+ * Is stdout a TTY? Colored output is enabled when `true`.
+ */
+
+function useColors() {
+	return 'colors' in exports.inspectOpts ?
+		Boolean(exports.inspectOpts.colors) :
+		tty.isatty(process.stderr.fd);
+}
+
+/**
+ * Adds ANSI color escape codes if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+	const {namespace: name, useColors} = this;
+
+	if (useColors) {
+		const c = this.color;
+		const colorCode = '\u001B[3' + (c < 8 ? c : '8;5;' + c);
+		const prefix = `  ${colorCode};1m${name} \u001B[0m`;
+
+		args[0] = prefix + args[0].split('\n').join('\n' + prefix);
+		args.push(colorCode + 'm+' + module.exports.humanize(this.diff) + '\u001B[0m');
+	} else {
+		args[0] = getDate() + name + ' ' + args[0];
+	}
+}
+
+function getDate() {
+	if (exports.inspectOpts.hideDate) {
+		return '';
+	}
+	return new Date().toISOString() + ' ';
+}
+
+/**
+ * Invokes `util.formatWithOptions()` with the specified arguments and writes to stderr.
+ */
+
+function log(...args) {
+	return process.stderr.write(util.formatWithOptions(exports.inspectOpts, ...args) + '\n');
+}
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+function save(namespaces) {
+	if (namespaces) {
+		process.env.DEBUG = namespaces;
+	} else {
+		// If you set a process.env field to null or undefined, it gets cast to the
+		// string 'null' or 'undefined'. Just delete instead.
+		delete process.env.DEBUG;
+	}
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+
+function load() {
+	return process.env.DEBUG;
+}
+
+/**
+ * Init logic for `debug` instances.
+ *
+ * Create a new `inspectOpts` object in case `useColors` is set
+ * differently for a particular `debug` instance.
+ */
+
+function init(debug) {
+	debug.inspectOpts = {};
+
+	const keys = Object.keys(exports.inspectOpts);
+	for (let i = 0; i < keys.length; i++) {
+		debug.inspectOpts[keys[i]] = exports.inspectOpts[keys[i]];
+	}
+}
+
+module.exports = require('./common')(exports);
+
+const {formatters} = module.exports;
+
+/**
+ * Map %o to `util.inspect()`, all on a single line.
+ */
+
+formatters.o = function (v) {
+	this.inspectOpts.colors = this.useColors;
+	return util.inspect(v, this.inspectOpts)
+		.split('\n')
+		.map(str => str.trim())
+		.join(' ');
+};
+
+/**
+ * Map %O to `util.inspect()`, allowing multiple lines if needed.
+ */
+
+formatters.O = function (v) {
+	this.inspectOpts.colors = this.useColors;
+	return util.inspect(v, this.inspectOpts);
+};
diff --git a/server/node_modules/agent-base/node_modules/ms/index.js b/server/node_modules/agent-base/node_modules/ms/index.js
new file mode 100644
index 0000000..ea734fb
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/ms/index.js
@@ -0,0 +1,162 @@
+/**
+ * Helpers.
+ */
+
+var s = 1000;
+var m = s * 60;
+var h = m * 60;
+var d = h * 24;
+var w = d * 7;
+var y = d * 365.25;
+
+/**
+ * Parse or format the given `val`.
+ *
+ * Options:
+ *
+ *  - `long` verbose formatting [false]
+ *
+ * @param {String|Number} val
+ * @param {Object} [options]
+ * @throws {Error} throw an error if val is not a non-empty string or a number
+ * @return {String|Number}
+ * @api public
+ */
+
+module.exports = function (val, options) {
+  options = options || {};
+  var type = typeof val;
+  if (type === 'string' && val.length > 0) {
+    return parse(val);
+  } else if (type === 'number' && isFinite(val)) {
+    return options.long ? fmtLong(val) : fmtShort(val);
+  }
+  throw new Error(
+    'val is not a non-empty string or a valid number. val=' +
+      JSON.stringify(val)
+  );
+};
+
+/**
+ * Parse the given `str` and return milliseconds.
+ *
+ * @param {String} str
+ * @return {Number}
+ * @api private
+ */
+
+function parse(str) {
+  str = String(str);
+  if (str.length > 100) {
+    return;
+  }
+  var match = /^(-?(?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|weeks?|w|years?|yrs?|y)?$/i.exec(
+    str
+  );
+  if (!match) {
+    return;
+  }
+  var n = parseFloat(match[1]);
+  var type = (match[2] || 'ms').toLowerCase();
+  switch (type) {
+    case 'years':
+    case 'year':
+    case 'yrs':
+    case 'yr':
+    case 'y':
+      return n * y;
+    case 'weeks':
+    case 'week':
+    case 'w':
+      return n * w;
+    case 'days':
+    case 'day':
+    case 'd':
+      return n * d;
+    case 'hours':
+    case 'hour':
+    case 'hrs':
+    case 'hr':
+    case 'h':
+      return n * h;
+    case 'minutes':
+    case 'minute':
+    case 'mins':
+    case 'min':
+    case 'm':
+      return n * m;
+    case 'seconds':
+    case 'second':
+    case 'secs':
+    case 'sec':
+    case 's':
+      return n * s;
+    case 'milliseconds':
+    case 'millisecond':
+    case 'msecs':
+    case 'msec':
+    case 'ms':
+      return n;
+    default:
+      return undefined;
+  }
+}
+
+/**
+ * Short format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtShort(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return Math.round(ms / d) + 'd';
+  }
+  if (msAbs >= h) {
+    return Math.round(ms / h) + 'h';
+  }
+  if (msAbs >= m) {
+    return Math.round(ms / m) + 'm';
+  }
+  if (msAbs >= s) {
+    return Math.round(ms / s) + 's';
+  }
+  return ms + 'ms';
+}
+
+/**
+ * Long format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtLong(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return plural(ms, msAbs, d, 'day');
+  }
+  if (msAbs >= h) {
+    return plural(ms, msAbs, h, 'hour');
+  }
+  if (msAbs >= m) {
+    return plural(ms, msAbs, m, 'minute');
+  }
+  if (msAbs >= s) {
+    return plural(ms, msAbs, s, 'second');
+  }
+  return ms + ' ms';
+}
+
+/**
+ * Pluralization helper.
+ */
+
+function plural(ms, msAbs, n, name) {
+  var isPlural = msAbs >= n * 1.5;
+  return Math.round(ms / n) + ' ' + name + (isPlural ? 's' : '');
+}
diff --git a/server/node_modules/agent-base/node_modules/ms/license.md b/server/node_modules/agent-base/node_modules/ms/license.md
new file mode 100644
index 0000000..fa5d39b
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/ms/license.md
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2020 Vercel, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/agent-base/node_modules/ms/package.json b/server/node_modules/agent-base/node_modules/ms/package.json
new file mode 100644
index 0000000..4997189
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/ms/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "ms",
+  "version": "2.1.3",
+  "description": "Tiny millisecond conversion utility",
+  "repository": "vercel/ms",
+  "main": "./index",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "precommit": "lint-staged",
+    "lint": "eslint lib/* bin/*",
+    "test": "mocha tests.js"
+  },
+  "eslintConfig": {
+    "extends": "eslint:recommended",
+    "env": {
+      "node": true,
+      "es6": true
+    }
+  },
+  "lint-staged": {
+    "*.js": [
+      "npm run lint",
+      "prettier --single-quote --write",
+      "git add"
+    ]
+  },
+  "license": "MIT",
+  "devDependencies": {
+    "eslint": "4.18.2",
+    "expect.js": "0.3.1",
+    "husky": "0.14.3",
+    "lint-staged": "5.0.0",
+    "mocha": "4.0.1",
+    "prettier": "2.0.5"
+  }
+}
diff --git a/server/node_modules/agent-base/node_modules/ms/readme.md b/server/node_modules/agent-base/node_modules/ms/readme.md
new file mode 100644
index 0000000..0fc1abb
--- /dev/null
+++ b/server/node_modules/agent-base/node_modules/ms/readme.md
@@ -0,0 +1,59 @@
+# ms
+
+![CI](https://github.com/vercel/ms/workflows/CI/badge.svg)
+
+Use this package to easily convert various time formats to milliseconds.
+
+## Examples
+
+```js
+ms('2 days')  // 172800000
+ms('1d')      // 86400000
+ms('10h')     // 36000000
+ms('2.5 hrs') // 9000000
+ms('2h')      // 7200000
+ms('1m')      // 60000
+ms('5s')      // 5000
+ms('1y')      // 31557600000
+ms('100')     // 100
+ms('-3 days') // -259200000
+ms('-1h')     // -3600000
+ms('-200')    // -200
+```
+
+### Convert from Milliseconds
+
+```js
+ms(60000)             // "1m"
+ms(2 * 60000)         // "2m"
+ms(-3 * 60000)        // "-3m"
+ms(ms('10 hours'))    // "10h"
+```
+
+### Time Format Written-Out
+
+```js
+ms(60000, { long: true })             // "1 minute"
+ms(2 * 60000, { long: true })         // "2 minutes"
+ms(-3 * 60000, { long: true })        // "-3 minutes"
+ms(ms('10 hours'), { long: true })    // "10 hours"
+```
+
+## Features
+
+- Works both in [Node.js](https://nodejs.org) and in the browser
+- If a number is supplied to `ms`, a string with a unit is returned
+- If a string that contains the number is supplied, it returns it as a number (e.g.: it returns `100` for `'100'`)
+- If you pass a string with a number and a valid unit, the number of equivalent milliseconds is returned
+
+## Related Packages
+
+- [ms.macro](https://github.com/knpwrs/ms.macro) - Run `ms` as a macro at build-time.
+
+## Caught a Bug?
+
+1. [Fork](https://help.github.com/articles/fork-a-repo/) this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device
+2. Link the package to the global module directory: `npm link`
+3. Within the module you want to test your local development instance of ms, just link it to the dependencies: `npm link ms`. Instead of the default one from npm, Node.js will now use your clone of ms!
+
+As always, you can run the tests using: `npm test`
diff --git a/server/node_modules/agent-base/package.json b/server/node_modules/agent-base/package.json
new file mode 100644
index 0000000..fadce3a
--- /dev/null
+++ b/server/node_modules/agent-base/package.json
@@ -0,0 +1,64 @@
+{
+  "name": "agent-base",
+  "version": "6.0.2",
+  "description": "Turn a function into an `http.Agent` instance",
+  "main": "dist/src/index",
+  "typings": "dist/src/index",
+  "files": [
+    "dist/src",
+    "src"
+  ],
+  "scripts": {
+    "prebuild": "rimraf dist",
+    "build": "tsc",
+    "postbuild": "cpy --parents src test '!**/*.ts' dist",
+    "test": "mocha --reporter spec dist/test/*.js",
+    "test-lint": "eslint src --ext .js,.ts",
+    "prepublishOnly": "npm run build"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/TooTallNate/node-agent-base.git"
+  },
+  "keywords": [
+    "http",
+    "agent",
+    "base",
+    "barebones",
+    "https"
+  ],
+  "author": "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io/)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/TooTallNate/node-agent-base/issues"
+  },
+  "dependencies": {
+    "debug": "4"
+  },
+  "devDependencies": {
+    "@types/debug": "4",
+    "@types/mocha": "^5.2.7",
+    "@types/node": "^14.0.20",
+    "@types/semver": "^7.1.0",
+    "@types/ws": "^6.0.3",
+    "@typescript-eslint/eslint-plugin": "1.6.0",
+    "@typescript-eslint/parser": "1.1.0",
+    "async-listen": "^1.2.0",
+    "cpy-cli": "^2.0.0",
+    "eslint": "5.16.0",
+    "eslint-config-airbnb": "17.1.0",
+    "eslint-config-prettier": "4.1.0",
+    "eslint-import-resolver-typescript": "1.1.1",
+    "eslint-plugin-import": "2.16.0",
+    "eslint-plugin-jsx-a11y": "6.2.1",
+    "eslint-plugin-react": "7.12.4",
+    "mocha": "^6.2.0",
+    "rimraf": "^3.0.0",
+    "semver": "^7.1.2",
+    "typescript": "^3.5.3",
+    "ws": "^3.0.0"
+  },
+  "engines": {
+    "node": ">= 6.0.0"
+  }
+}
diff --git a/server/node_modules/agent-base/src/index.ts b/server/node_modules/agent-base/src/index.ts
new file mode 100644
index 0000000..a47ccd4
--- /dev/null
+++ b/server/node_modules/agent-base/src/index.ts
@@ -0,0 +1,345 @@
+import net from 'net';
+import http from 'http';
+import https from 'https';
+import { Duplex } from 'stream';
+import { EventEmitter } from 'events';
+import createDebug from 'debug';
+import promisify from './promisify';
+
+const debug = createDebug('agent-base');
+
+function isAgent(v: any): v is createAgent.AgentLike {
+	return Boolean(v) && typeof v.addRequest === 'function';
+}
+
+function isSecureEndpoint(): boolean {
+	const { stack } = new Error();
+	if (typeof stack !== 'string') return false;
+	return stack.split('\n').some(l => l.indexOf('(https.js:') !== -1  || l.indexOf('node:https:') !== -1);
+}
+
+function createAgent(opts?: createAgent.AgentOptions): createAgent.Agent;
+function createAgent(
+	callback: createAgent.AgentCallback,
+	opts?: createAgent.AgentOptions
+): createAgent.Agent;
+function createAgent(
+	callback?: createAgent.AgentCallback | createAgent.AgentOptions,
+	opts?: createAgent.AgentOptions
+) {
+	return new createAgent.Agent(callback, opts);
+}
+
+namespace createAgent {
+	export interface ClientRequest extends http.ClientRequest {
+		_last?: boolean;
+		_hadError?: boolean;
+		method: string;
+	}
+
+	export interface AgentRequestOptions {
+		host?: string;
+		path?: string;
+		// `port` on `http.RequestOptions` can be a string or undefined,
+		// but `net.TcpNetConnectOpts` expects only a number
+		port: number;
+	}
+
+	export interface HttpRequestOptions
+		extends AgentRequestOptions,
+			Omit<http.RequestOptions, keyof AgentRequestOptions> {
+		secureEndpoint: false;
+	}
+
+	export interface HttpsRequestOptions
+		extends AgentRequestOptions,
+			Omit<https.RequestOptions, keyof AgentRequestOptions> {
+		secureEndpoint: true;
+	}
+
+	export type RequestOptions = HttpRequestOptions | HttpsRequestOptions;
+
+	export type AgentLike = Pick<createAgent.Agent, 'addRequest'> | http.Agent;
+
+	export type AgentCallbackReturn = Duplex | AgentLike;
+
+	export type AgentCallbackCallback = (
+		err?: Error | null,
+		socket?: createAgent.AgentCallbackReturn
+	) => void;
+
+	export type AgentCallbackPromise = (
+		req: createAgent.ClientRequest,
+		opts: createAgent.RequestOptions
+	) =>
+		| createAgent.AgentCallbackReturn
+		| Promise<createAgent.AgentCallbackReturn>;
+
+	export type AgentCallback = typeof Agent.prototype.callback;
+
+	export type AgentOptions = {
+		timeout?: number;
+	};
+
+	/**
+	 * Base `http.Agent` implementation.
+	 * No pooling/keep-alive is implemented by default.
+	 *
+	 * @param {Function} callback
+	 * @api public
+	 */
+	export class Agent extends EventEmitter {
+		public timeout: number | null;
+		public maxFreeSockets: number;
+		public maxTotalSockets: number;
+		public maxSockets: number;
+		public sockets: {
+			[key: string]: net.Socket[];
+		};
+		public freeSockets: {
+			[key: string]: net.Socket[];
+		};
+		public requests: {
+			[key: string]: http.IncomingMessage[];
+		};
+		public options: https.AgentOptions;
+		private promisifiedCallback?: createAgent.AgentCallbackPromise;
+		private explicitDefaultPort?: number;
+		private explicitProtocol?: string;
+
+		constructor(
+			callback?: createAgent.AgentCallback | createAgent.AgentOptions,
+			_opts?: createAgent.AgentOptions
+		) {
+			super();
+
+			let opts = _opts;
+			if (typeof callback === 'function') {
+				this.callback = callback;
+			} else if (callback) {
+				opts = callback;
+			}
+
+			// Timeout for the socket to be returned from the callback
+			this.timeout = null;
+			if (opts && typeof opts.timeout === 'number') {
+				this.timeout = opts.timeout;
+			}
+
+			// These aren't actually used by `agent-base`, but are required
+			// for the TypeScript definition files in `@types/node` :/
+			this.maxFreeSockets = 1;
+			this.maxSockets = 1;
+			this.maxTotalSockets = Infinity;
+			this.sockets = {};
+			this.freeSockets = {};
+			this.requests = {};
+			this.options = {};
+		}
+
+		get defaultPort(): number {
+			if (typeof this.explicitDefaultPort === 'number') {
+				return this.explicitDefaultPort;
+			}
+			return isSecureEndpoint() ? 443 : 80;
+		}
+
+		set defaultPort(v: number) {
+			this.explicitDefaultPort = v;
+		}
+
+		get protocol(): string {
+			if (typeof this.explicitProtocol === 'string') {
+				return this.explicitProtocol;
+			}
+			return isSecureEndpoint() ? 'https:' : 'http:';
+		}
+
+		set protocol(v: string) {
+			this.explicitProtocol = v;
+		}
+
+		callback(
+			req: createAgent.ClientRequest,
+			opts: createAgent.RequestOptions,
+			fn: createAgent.AgentCallbackCallback
+		): void;
+		callback(
+			req: createAgent.ClientRequest,
+			opts: createAgent.RequestOptions
+		):
+			| createAgent.AgentCallbackReturn
+			| Promise<createAgent.AgentCallbackReturn>;
+		callback(
+			req: createAgent.ClientRequest,
+			opts: createAgent.AgentOptions,
+			fn?: createAgent.AgentCallbackCallback
+		):
+			| createAgent.AgentCallbackReturn
+			| Promise<createAgent.AgentCallbackReturn>
+			| void {
+			throw new Error(
+				'"agent-base" has no default implementation, you must subclass and override `callback()`'
+			);
+		}
+
+		/**
+		 * Called by node-core's "_http_client.js" module when creating
+		 * a new HTTP request with this Agent instance.
+		 *
+		 * @api public
+		 */
+		addRequest(req: ClientRequest, _opts: RequestOptions): void {
+			const opts: RequestOptions = { ..._opts };
+
+			if (typeof opts.secureEndpoint !== 'boolean') {
+				opts.secureEndpoint = isSecureEndpoint();
+			}
+
+			if (opts.host == null) {
+				opts.host = 'localhost';
+			}
+
+			if (opts.port == null) {
+				opts.port = opts.secureEndpoint ? 443 : 80;
+			}
+
+			if (opts.protocol == null) {
+				opts.protocol = opts.secureEndpoint ? 'https:' : 'http:';
+			}
+
+			if (opts.host && opts.path) {
+				// If both a `host` and `path` are specified then it's most
+				// likely the result of a `url.parse()` call... we need to
+				// remove the `path` portion so that `net.connect()` doesn't
+				// attempt to open that as a unix socket file.
+				delete opts.path;
+			}
+
+			delete opts.agent;
+			delete opts.hostname;
+			delete opts._defaultAgent;
+			delete opts.defaultPort;
+			delete opts.createConnection;
+
+			// Hint to use "Connection: close"
+			// XXX: non-documented `http` module API :(
+			req._last = true;
+			req.shouldKeepAlive = false;
+
+			let timedOut = false;
+			let timeoutId: ReturnType<typeof setTimeout> | null = null;
+			const timeoutMs = opts.timeout || this.timeout;
+
+			const onerror = (err: NodeJS.ErrnoException) => {
+				if (req._hadError) return;
+				req.emit('error', err);
+				// For Safety. Some additional errors might fire later on
+				// and we need to make sure we don't double-fire the error event.
+				req._hadError = true;
+			};
+
+			const ontimeout = () => {
+				timeoutId = null;
+				timedOut = true;
+				const err: NodeJS.ErrnoException = new Error(
+					`A "socket" was not created for HTTP request before ${timeoutMs}ms`
+				);
+				err.code = 'ETIMEOUT';
+				onerror(err);
+			};
+
+			const callbackError = (err: NodeJS.ErrnoException) => {
+				if (timedOut) return;
+				if (timeoutId !== null) {
+					clearTimeout(timeoutId);
+					timeoutId = null;
+				}
+				onerror(err);
+			};
+
+			const onsocket = (socket: AgentCallbackReturn) => {
+				if (timedOut) return;
+				if (timeoutId != null) {
+					clearTimeout(timeoutId);
+					timeoutId = null;
+				}
+
+				if (isAgent(socket)) {
+					// `socket` is actually an `http.Agent` instance, so
+					// relinquish responsibility for this `req` to the Agent
+					// from here on
+					debug(
+						'Callback returned another Agent instance %o',
+						socket.constructor.name
+					);
+					(socket as createAgent.Agent).addRequest(req, opts);
+					return;
+				}
+
+				if (socket) {
+					socket.once('free', () => {
+						this.freeSocket(socket as net.Socket, opts);
+					});
+					req.onSocket(socket as net.Socket);
+					return;
+				}
+
+				const err = new Error(
+					`no Duplex stream was returned to agent-base for \`${req.method} ${req.path}\``
+				);
+				onerror(err);
+			};
+
+			if (typeof this.callback !== 'function') {
+				onerror(new Error('`callback` is not defined'));
+				return;
+			}
+
+			if (!this.promisifiedCallback) {
+				if (this.callback.length >= 3) {
+					debug('Converting legacy callback function to promise');
+					this.promisifiedCallback = promisify(this.callback);
+				} else {
+					this.promisifiedCallback = this.callback;
+				}
+			}
+
+			if (typeof timeoutMs === 'number' && timeoutMs > 0) {
+				timeoutId = setTimeout(ontimeout, timeoutMs);
+			}
+
+			if ('port' in opts && typeof opts.port !== 'number') {
+				opts.port = Number(opts.port);
+			}
+
+			try {
+				debug(
+					'Resolving socket for %o request: %o',
+					opts.protocol,
+					`${req.method} ${req.path}`
+				);
+				Promise.resolve(this.promisifiedCallback(req, opts)).then(
+					onsocket,
+					callbackError
+				);
+			} catch (err) {
+				Promise.reject(err).catch(callbackError);
+			}
+		}
+
+		freeSocket(socket: net.Socket, opts: AgentOptions) {
+			debug('Freeing socket %o %o', socket.constructor.name, opts);
+			socket.destroy();
+		}
+
+		destroy() {
+			debug('Destroying agent %o', this.constructor.name);
+		}
+	}
+
+	// So that `instanceof` works correctly
+	createAgent.prototype = createAgent.Agent.prototype;
+}
+
+export = createAgent;
diff --git a/server/node_modules/agent-base/src/promisify.ts b/server/node_modules/agent-base/src/promisify.ts
new file mode 100644
index 0000000..60cc662
--- /dev/null
+++ b/server/node_modules/agent-base/src/promisify.ts
@@ -0,0 +1,33 @@
+import {
+	Agent,
+	ClientRequest,
+	RequestOptions,
+	AgentCallbackCallback,
+	AgentCallbackPromise,
+	AgentCallbackReturn
+} from './index';
+
+type LegacyCallback = (
+	req: ClientRequest,
+	opts: RequestOptions,
+	fn: AgentCallbackCallback
+) => void;
+
+export default function promisify(fn: LegacyCallback): AgentCallbackPromise {
+	return function(this: Agent, req: ClientRequest, opts: RequestOptions) {
+		return new Promise((resolve, reject) => {
+			fn.call(
+				this,
+				req,
+				opts,
+				(err: Error | null | undefined, rtn?: AgentCallbackReturn) => {
+					if (err) {
+						reject(err);
+					} else {
+						resolve(rtn);
+					}
+				}
+			);
+		});
+	};
+}
diff --git a/server/node_modules/agentkeepalive/LICENSE b/server/node_modules/agentkeepalive/LICENSE
new file mode 100644
index 0000000..941258c
--- /dev/null
+++ b/server/node_modules/agentkeepalive/LICENSE
@@ -0,0 +1,23 @@
+The MIT License
+
+Copyright(c) node-modules and other contributors.
+Copyright(c) 2012 - 2015 fengmk2 <fengmk2@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/agentkeepalive/README.md b/server/node_modules/agentkeepalive/README.md
new file mode 100644
index 0000000..6a7ee5a
--- /dev/null
+++ b/server/node_modules/agentkeepalive/README.md
@@ -0,0 +1,256 @@
+# agentkeepalive
+
+[![NPM version][npm-image]][npm-url]
+[![Known Vulnerabilities][snyk-image]][snyk-url]
+[![Node.js CI](https://github.com/node-modules/agentkeepalive/actions/workflows/nodejs.yml/badge.svg)](https://github.com/node-modules/agentkeepalive/actions/workflows/nodejs.yml)
+[![npm download][download-image]][download-url]
+
+[npm-image]: https://img.shields.io/npm/v/agentkeepalive.svg?style=flat
+[npm-url]: https://npmjs.org/package/agentkeepalive
+[snyk-image]: https://snyk.io/test/npm/agentkeepalive/badge.svg?style=flat-square
+[snyk-url]: https://snyk.io/test/npm/agentkeepalive
+[download-image]: https://img.shields.io/npm/dm/agentkeepalive.svg?style=flat-square
+[download-url]: https://npmjs.org/package/agentkeepalive
+
+The enhancement features `keep alive` `http.Agent`. Support `http` and `https`.
+
+## What's different from original `http.Agent`?
+
+- `keepAlive=true` by default
+- Disable Nagle's algorithm: `socket.setNoDelay(true)`
+- Add free socket timeout: avoid long time inactivity socket leak in the free-sockets queue.
+- Add active socket timeout: avoid long time inactivity socket leak in the active-sockets queue.
+- TTL for active socket.
+
+## Node.js version required
+
+Support Node.js >= `8.0.0`
+
+## Install
+
+```bash
+$ npm install agentkeepalive --save
+```
+
+## new Agent([options])
+
+* `options` {Object} Set of configurable options to set on the agent.
+  Can have the following fields:
+  * `keepAlive` {Boolean} Keep sockets around in a pool to be used by
+    other requests in the future. Default = `true`.
+  * `keepAliveMsecs` {Number} When using the keepAlive option, specifies the initial delay
+    for TCP Keep-Alive packets. Ignored when the keepAlive option is false or undefined. Defaults to 1000.
+    Default = `1000`.  Only relevant if `keepAlive` is set to `true`.
+  * `freeSocketTimeout`: {Number} Sets the free socket to timeout
+    after `freeSocketTimeout` milliseconds of inactivity on the free socket.
+    The default [server-side timeout](https://nodejs.org/api/http.html#serverkeepalivetimeout) is 5000 milliseconds, to [avoid ECONNRESET exceptions](https://medium.com/ssense-tech/reduce-networking-errors-in-nodejs-23b4eb9f2d83), we set the default value to `4000` milliseconds.
+    Only relevant if `keepAlive` is set to `true`.
+  * `timeout`: {Number} Sets the working socket to timeout
+    after `timeout` milliseconds of inactivity on the working socket.
+    Default is `freeSocketTimeout * 2` so long as that value is greater than or equal to 8 seconds, otherwise the default is 8 seconds.
+  * `maxSockets` {Number} Maximum number of sockets to allow per
+    host. Default = `Infinity`.
+  * `maxFreeSockets` {Number} Maximum number of sockets (per host) to leave open
+    in a free state. Only relevant if `keepAlive` is set to `true`.
+    Default = `256`.
+  * `socketActiveTTL` {Number} Sets the socket active time to live, even if it's in use.
+    If not set, the behaviour keeps the same (the socket will be released only when free)
+    Default = `null`.
+
+## Usage
+
+```js
+const http = require('http');
+const HttpAgent = require('agentkeepalive').HttpAgent;
+
+const keepaliveAgent = new HttpAgent({
+  maxSockets: 100,
+  maxFreeSockets: 10,
+  timeout: 60000, // active socket keepalive for 60 seconds
+  freeSocketTimeout: 30000, // free socket keepalive for 30 seconds
+});
+
+const options = {
+  host: 'cnodejs.org',
+  port: 80,
+  path: '/',
+  method: 'GET',
+  agent: keepaliveAgent,
+};
+
+const req = http.request(options, res => {
+  console.log('STATUS: ' + res.statusCode);
+  console.log('HEADERS: ' + JSON.stringify(res.headers));
+  res.setEncoding('utf8');
+  res.on('data', function (chunk) {
+    console.log('BODY: ' + chunk);
+  });
+});
+req.on('error', e => {
+  console.log('problem with request: ' + e.message);
+});
+req.end();
+
+setTimeout(() => {
+  if (keepaliveAgent.statusChanged) {
+    console.log('[%s] agent status changed: %j', Date(), keepaliveAgent.getCurrentStatus());
+  }
+}, 2000);
+
+```
+
+### `getter agent.statusChanged`
+
+counters have change or not after last checkpoint.
+
+### `agent.getCurrentStatus()`
+
+`agent.getCurrentStatus()` will return a object to show the status of this agent:
+
+```js
+{
+  createSocketCount: 10,
+  closeSocketCount: 5,
+  timeoutSocketCount: 0,
+  requestCount: 5,
+  freeSockets: { 'localhost:57479:': 3 },
+  sockets: { 'localhost:57479:': 5 },
+  requests: {}
+}
+```
+
+### Support `https`
+
+```js
+const https = require('https');
+const HttpsAgent = require('agentkeepalive').HttpsAgent;
+
+const keepaliveAgent = new HttpsAgent();
+// https://www.google.com/search?q=nodejs&sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8
+const options = {
+  host: 'www.google.com',
+  port: 443,
+  path: '/search?q=nodejs&sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8',
+  method: 'GET',
+  agent: keepaliveAgent,
+};
+
+const req = https.request(options, res => {
+  console.log('STATUS: ' + res.statusCode);
+  console.log('HEADERS: ' + JSON.stringify(res.headers));
+  res.setEncoding('utf8');
+  res.on('data', chunk => {
+    console.log('BODY: ' + chunk);
+  });
+});
+
+req.on('error', e => {
+  console.log('problem with request: ' + e.message);
+});
+req.end();
+
+setTimeout(() => {
+  console.log('agent status: %j', keepaliveAgent.getCurrentStatus());
+}, 2000);
+```
+
+### Support `req.reusedSocket`
+
+This agent implements the `req.reusedSocket` to determine whether a request is send through a reused socket.
+
+When server closes connection at unfortunate time ([keep-alive race](https://code-examples.net/en/q/28a8069)), the http client will throw a `ECONNRESET` error. Under this circumstance, `req.reusedSocket` is useful when we want to retry the request automatically.
+
+```js
+const http = require('http');
+const HttpAgent = require('agentkeepalive').HttpAgent;
+const agent = new HttpAgent();
+
+const req = http
+  .get('http://localhost:3000', { agent }, (res) => {
+    // ...
+  })
+  .on('error', (err) => {
+    if (req.reusedSocket && err.code === 'ECONNRESET') {
+      // retry the request or anything else...
+    }
+  })
+```
+
+This behavior is consistent with Node.js core. But through `agentkeepalive`, you can use this feature in older Node.js version.
+
+## [Benchmark](https://github.com/node-modules/agentkeepalive/tree/master/benchmark)
+
+run the benchmark:
+
+```bash
+cd benchmark
+sh start.sh
+```
+
+Intel(R) Core(TM)2 Duo CPU     P8600  @ 2.40GHz
+
+node@v0.8.9
+
+50 maxSockets, 60 concurrent, 1000 requests per concurrent, 5ms delay
+
+Keep alive agent (30 seconds):
+
+```js
+Transactions:          60000 hits
+Availability:         100.00 %
+Elapsed time:          29.70 secs
+Data transferred:        14.88 MB
+Response time:            0.03 secs
+Transaction rate:      2020.20 trans/sec
+Throughput:           0.50 MB/sec
+Concurrency:           59.84
+Successful transactions:       60000
+Failed transactions:             0
+Longest transaction:          0.15
+Shortest transaction:         0.01
+```
+
+Normal agent:
+
+```js
+Transactions:          60000 hits
+Availability:         100.00 %
+Elapsed time:          46.53 secs
+Data transferred:        14.88 MB
+Response time:            0.05 secs
+Transaction rate:      1289.49 trans/sec
+Throughput:           0.32 MB/sec
+Concurrency:           59.81
+Successful transactions:       60000
+Failed transactions:             0
+Longest transaction:          0.45
+Shortest transaction:         0.00
+```
+
+Socket created:
+
+```bash
+[proxy.js:120000] keepalive, 50 created, 60000 requestFinished, 1200 req/socket, 0 requests, 0 sockets, 0 unusedSockets, 50 timeout
+{" <10ms":662," <15ms":17825," <20ms":20552," <30ms":17646," <40ms":2315," <50ms":567," <100ms":377," <150ms":56," <200ms":0," >=200ms+":0}
+----------------------------------------------------------------
+[proxy.js:120000] normal   , 53866 created, 84260 requestFinished, 1.56 req/socket, 0 requests, 0 sockets
+{" <10ms":75," <15ms":1112," <20ms":10947," <30ms":32130," <40ms":8228," <50ms":3002," <100ms":4274," <150ms":181," <200ms":18," >=200ms+":33}
+```
+
+## License
+
+[MIT](LICENSE)
+
+
+
+## Contributors
+
+|[<img src="https://avatars.githubusercontent.com/u/156269?v=4" width="100px;"/><br/><sub><b>fengmk2</b></sub>](https://github.com/fengmk2)<br/>|[<img src="https://avatars.githubusercontent.com/u/985607?v=4" width="100px;"/><br/><sub><b>dead-horse</b></sub>](https://github.com/dead-horse)<br/>|[<img src="https://avatars.githubusercontent.com/u/5557458?v=4" width="100px;"/><br/><sub><b>AndrewLeedham</b></sub>](https://github.com/AndrewLeedham)<br/>|[<img src="https://avatars.githubusercontent.com/u/5243774?v=4" width="100px;"/><br/><sub><b>ngot</b></sub>](https://github.com/ngot)<br/>|[<img src="https://avatars.githubusercontent.com/u/25919630?v=4" width="100px;"/><br/><sub><b>wrynearson</b></sub>](https://github.com/wrynearson)<br/>|[<img src="https://avatars.githubusercontent.com/u/26738844?v=4" width="100px;"/><br/><sub><b>aaronArinder</b></sub>](https://github.com/aaronArinder)<br/>|
+| :---: | :---: | :---: | :---: | :---: | :---: |
+|[<img src="https://avatars.githubusercontent.com/u/10976983?v=4" width="100px;"/><br/><sub><b>alexpenev-s</b></sub>](https://github.com/alexpenev-s)<br/>|[<img src="https://avatars.githubusercontent.com/u/959726?v=4" width="100px;"/><br/><sub><b>blemoine</b></sub>](https://github.com/blemoine)<br/>|[<img src="https://avatars.githubusercontent.com/u/398027?v=4" width="100px;"/><br/><sub><b>bdehamer</b></sub>](https://github.com/bdehamer)<br/>|[<img src="https://avatars.githubusercontent.com/u/4985201?v=4" width="100px;"/><br/><sub><b>DylanPiercey</b></sub>](https://github.com/DylanPiercey)<br/>|[<img src="https://avatars.githubusercontent.com/u/3770250?v=4" width="100px;"/><br/><sub><b>cixel</b></sub>](https://github.com/cixel)<br/>|[<img src="https://avatars.githubusercontent.com/u/2883231?v=4" width="100px;"/><br/><sub><b>HerringtonDarkholme</b></sub>](https://github.com/HerringtonDarkholme)<br/>|
+|[<img src="https://avatars.githubusercontent.com/u/1433247?v=4" width="100px;"/><br/><sub><b>denghongcai</b></sub>](https://github.com/denghongcai)<br/>|[<img src="https://avatars.githubusercontent.com/u/1847934?v=4" width="100px;"/><br/><sub><b>kibertoad</b></sub>](https://github.com/kibertoad)<br/>|[<img src="https://avatars.githubusercontent.com/u/5236150?v=4" width="100px;"/><br/><sub><b>pangorgo</b></sub>](https://github.com/pangorgo)<br/>|[<img src="https://avatars.githubusercontent.com/u/588898?v=4" width="100px;"/><br/><sub><b>mattiash</b></sub>](https://github.com/mattiash)<br/>|[<img src="https://avatars.githubusercontent.com/u/182440?v=4" width="100px;"/><br/><sub><b>nabeelbukhari</b></sub>](https://github.com/nabeelbukhari)<br/>|[<img src="https://avatars.githubusercontent.com/u/1411117?v=4" width="100px;"/><br/><sub><b>pmalouin</b></sub>](https://github.com/pmalouin)<br/>|
+[<img src="https://avatars.githubusercontent.com/u/1404810?v=4" width="100px;"/><br/><sub><b>SimenB</b></sub>](https://github.com/SimenB)<br/>|[<img src="https://avatars.githubusercontent.com/u/2630384?v=4" width="100px;"/><br/><sub><b>vinaybedre</b></sub>](https://github.com/vinaybedre)<br/>|[<img src="https://avatars.githubusercontent.com/u/10933333?v=4" width="100px;"/><br/><sub><b>starkwang</b></sub>](https://github.com/starkwang)<br/>|[<img src="https://avatars.githubusercontent.com/u/6897780?v=4" width="100px;"/><br/><sub><b>killagu</b></sub>](https://github.com/killagu)<br/>|[<img src="https://avatars.githubusercontent.com/u/15345331?v=4" width="100px;"/><br/><sub><b>tony-gutierrez</b></sub>](https://github.com/tony-gutierrez)<br/>|[<img src="https://avatars.githubusercontent.com/u/5856440?v=4" width="100px;"/><br/><sub><b>whxaxes</b></sub>](https://github.com/whxaxes)<br/>
+
+This project follows the git-contributor [spec](https://github.com/xudafeng/git-contributor), auto updated at `Sat Aug 05 2023 02:36:31 GMT+0800`.
+
+
diff --git a/server/node_modules/agentkeepalive/browser.js b/server/node_modules/agentkeepalive/browser.js
new file mode 100644
index 0000000..29c9398
--- /dev/null
+++ b/server/node_modules/agentkeepalive/browser.js
@@ -0,0 +1,5 @@
+module.exports = noop;
+module.exports.HttpsAgent = noop;
+
+// Noop function for browser since native api's don't use agents.
+function noop () {}
diff --git a/server/node_modules/agentkeepalive/index.d.ts b/server/node_modules/agentkeepalive/index.d.ts
new file mode 100644
index 0000000..f4dbcec
--- /dev/null
+++ b/server/node_modules/agentkeepalive/index.d.ts
@@ -0,0 +1,69 @@
+import * as http from 'http';
+import * as https from 'https';
+import * as net from 'net';
+
+interface PlainObject {
+  [key: string]: any;
+}
+
+declare class _HttpAgent extends http.Agent {
+  constructor(opts?: AgentKeepAlive.HttpOptions);
+  readonly statusChanged: boolean;
+  createConnection(options: net.NetConnectOpts, cb?: Function): net.Socket;
+  createSocket(req: http.IncomingMessage, options: http.RequestOptions, cb: Function): void;
+  getCurrentStatus(): AgentKeepAlive.AgentStatus;
+}
+
+interface Constants {
+  CURRENT_ID: Symbol;
+  CREATE_ID: Symbol;
+  INIT_SOCKET: Symbol;
+  CREATE_HTTPS_CONNECTION: Symbol;
+  SOCKET_CREATED_TIME: Symbol;
+  SOCKET_NAME: Symbol;
+  SOCKET_REQUEST_COUNT: Symbol;
+  SOCKET_REQUEST_FINISHED_COUNT: Symbol;
+}
+
+/**
+ * @deprecated instead use `import { HttpAgent } from 'agentkeepalive'; or `const HttpAgent = require('agentkeepalive').HttpAgent;`
+ */
+declare class AgentKeepAlive extends _HttpAgent {}
+
+declare namespace AgentKeepAlive {
+  export interface AgentStatus {
+    createSocketCount: number;
+    createSocketErrorCount: number;
+    closeSocketCount: number;
+    errorSocketCount: number;
+    timeoutSocketCount: number;
+    requestCount: number;
+    freeSockets: PlainObject;
+    sockets: PlainObject;
+    requests: PlainObject;
+  }
+
+  interface CommonHttpOption {
+    keepAlive?: boolean | undefined;
+    freeSocketTimeout?: number | undefined;
+    freeSocketKeepAliveTimeout?: number | undefined;
+    timeout?: number | undefined;
+    socketActiveTTL?: number | undefined;
+  }
+
+  export interface HttpOptions extends http.AgentOptions, CommonHttpOption { }
+  export interface HttpsOptions extends https.AgentOptions, CommonHttpOption { }
+
+  export class HttpAgent extends _HttpAgent {}
+  export class HttpsAgent extends https.Agent {
+    constructor(opts?: HttpsOptions);
+    readonly statusChanged: boolean;
+    createConnection(options: net.NetConnectOpts, cb?: Function): net.Socket;
+    createSocket(req: http.IncomingMessage, options: http.RequestOptions, cb: Function): void;
+    getCurrentStatus(): AgentStatus;
+  }
+
+  export const constants: Constants;
+}
+
+export = AgentKeepAlive;
diff --git a/server/node_modules/agentkeepalive/index.js b/server/node_modules/agentkeepalive/index.js
new file mode 100644
index 0000000..cfe41dc
--- /dev/null
+++ b/server/node_modules/agentkeepalive/index.js
@@ -0,0 +1,7 @@
+'use strict';
+
+const HttpAgent = require('./lib/agent');
+module.exports = HttpAgent;
+module.exports.HttpAgent = HttpAgent;
+module.exports.HttpsAgent = require('./lib/https_agent');
+module.exports.constants = require('./lib/constants');
diff --git a/server/node_modules/agentkeepalive/lib/agent.js b/server/node_modules/agentkeepalive/lib/agent.js
new file mode 100644
index 0000000..8bd354e
--- /dev/null
+++ b/server/node_modules/agentkeepalive/lib/agent.js
@@ -0,0 +1,402 @@
+'use strict';
+
+const OriginalAgent = require('http').Agent;
+const ms = require('humanize-ms');
+const debug = require('util').debuglog('agentkeepalive');
+const {
+  INIT_SOCKET,
+  CURRENT_ID,
+  CREATE_ID,
+  SOCKET_CREATED_TIME,
+  SOCKET_NAME,
+  SOCKET_REQUEST_COUNT,
+  SOCKET_REQUEST_FINISHED_COUNT,
+} = require('./constants');
+
+// OriginalAgent come from
+// - https://github.com/nodejs/node/blob/v8.12.0/lib/_http_agent.js
+// - https://github.com/nodejs/node/blob/v10.12.0/lib/_http_agent.js
+
+// node <= 10
+let defaultTimeoutListenerCount = 1;
+const majorVersion = parseInt(process.version.split('.', 1)[0].substring(1));
+if (majorVersion >= 11 && majorVersion <= 12) {
+  defaultTimeoutListenerCount = 2;
+} else if (majorVersion >= 13) {
+  defaultTimeoutListenerCount = 3;
+}
+
+function deprecate(message) {
+  console.log('[agentkeepalive:deprecated] %s', message);
+}
+
+class Agent extends OriginalAgent {
+  constructor(options) {
+    options = options || {};
+    options.keepAlive = options.keepAlive !== false;
+    // default is keep-alive and 4s free socket timeout
+    // see https://medium.com/ssense-tech/reduce-networking-errors-in-nodejs-23b4eb9f2d83
+    if (options.freeSocketTimeout === undefined) {
+      options.freeSocketTimeout = 4000;
+    }
+    // Legacy API: keepAliveTimeout should be rename to `freeSocketTimeout`
+    if (options.keepAliveTimeout) {
+      deprecate('options.keepAliveTimeout is deprecated, please use options.freeSocketTimeout instead');
+      options.freeSocketTimeout = options.keepAliveTimeout;
+      delete options.keepAliveTimeout;
+    }
+    // Legacy API: freeSocketKeepAliveTimeout should be rename to `freeSocketTimeout`
+    if (options.freeSocketKeepAliveTimeout) {
+      deprecate('options.freeSocketKeepAliveTimeout is deprecated, please use options.freeSocketTimeout instead');
+      options.freeSocketTimeout = options.freeSocketKeepAliveTimeout;
+      delete options.freeSocketKeepAliveTimeout;
+    }
+
+    // Sets the socket to timeout after timeout milliseconds of inactivity on the socket.
+    // By default is double free socket timeout.
+    if (options.timeout === undefined) {
+      // make sure socket default inactivity timeout >= 8s
+      options.timeout = Math.max(options.freeSocketTimeout * 2, 8000);
+    }
+
+    // support humanize format
+    options.timeout = ms(options.timeout);
+    options.freeSocketTimeout = ms(options.freeSocketTimeout);
+    options.socketActiveTTL = options.socketActiveTTL ? ms(options.socketActiveTTL) : 0;
+
+    super(options);
+
+    this[CURRENT_ID] = 0;
+
+    // create socket success counter
+    this.createSocketCount = 0;
+    this.createSocketCountLastCheck = 0;
+
+    this.createSocketErrorCount = 0;
+    this.createSocketErrorCountLastCheck = 0;
+
+    this.closeSocketCount = 0;
+    this.closeSocketCountLastCheck = 0;
+
+    // socket error event count
+    this.errorSocketCount = 0;
+    this.errorSocketCountLastCheck = 0;
+
+    // request finished counter
+    this.requestCount = 0;
+    this.requestCountLastCheck = 0;
+
+    // including free socket timeout counter
+    this.timeoutSocketCount = 0;
+    this.timeoutSocketCountLastCheck = 0;
+
+    this.on('free', socket => {
+      // https://github.com/nodejs/node/pull/32000
+      // Node.js native agent will check socket timeout eqs agent.options.timeout.
+      // Use the ttl or freeSocketTimeout to overwrite.
+      const timeout = this.calcSocketTimeout(socket);
+      if (timeout > 0 && socket.timeout !== timeout) {
+        socket.setTimeout(timeout);
+      }
+    });
+  }
+
+  get freeSocketKeepAliveTimeout() {
+    deprecate('agent.freeSocketKeepAliveTimeout is deprecated, please use agent.options.freeSocketTimeout instead');
+    return this.options.freeSocketTimeout;
+  }
+
+  get timeout() {
+    deprecate('agent.timeout is deprecated, please use agent.options.timeout instead');
+    return this.options.timeout;
+  }
+
+  get socketActiveTTL() {
+    deprecate('agent.socketActiveTTL is deprecated, please use agent.options.socketActiveTTL instead');
+    return this.options.socketActiveTTL;
+  }
+
+  calcSocketTimeout(socket) {
+    /**
+     * return <= 0: should free socket
+     * return > 0: should update socket timeout
+     * return undefined: not find custom timeout
+     */
+    let freeSocketTimeout = this.options.freeSocketTimeout;
+    const socketActiveTTL = this.options.socketActiveTTL;
+    if (socketActiveTTL) {
+      // check socketActiveTTL
+      const aliveTime = Date.now() - socket[SOCKET_CREATED_TIME];
+      const diff = socketActiveTTL - aliveTime;
+      if (diff <= 0) {
+        return diff;
+      }
+      if (freeSocketTimeout && diff < freeSocketTimeout) {
+        freeSocketTimeout = diff;
+      }
+    }
+    // set freeSocketTimeout
+    if (freeSocketTimeout) {
+      // set free keepalive timer
+      // try to use socket custom freeSocketTimeout first, support headers['keep-alive']
+      // https://github.com/node-modules/urllib/blob/b76053020923f4d99a1c93cf2e16e0c5ba10bacf/lib/urllib.js#L498
+      const customFreeSocketTimeout = socket.freeSocketTimeout || socket.freeSocketKeepAliveTimeout;
+      return customFreeSocketTimeout || freeSocketTimeout;
+    }
+  }
+
+  keepSocketAlive(socket) {
+    const result = super.keepSocketAlive(socket);
+    // should not keepAlive, do nothing
+    if (!result) return result;
+
+    const customTimeout = this.calcSocketTimeout(socket);
+    if (typeof customTimeout === 'undefined') {
+      return true;
+    }
+    if (customTimeout <= 0) {
+      debug('%s(requests: %s, finished: %s) free but need to destroy by TTL, request count %s, diff is %s',
+        socket[SOCKET_NAME], socket[SOCKET_REQUEST_COUNT], socket[SOCKET_REQUEST_FINISHED_COUNT], customTimeout);
+      return false;
+    }
+    if (socket.timeout !== customTimeout) {
+      socket.setTimeout(customTimeout);
+    }
+    return true;
+  }
+
+  // only call on addRequest
+  reuseSocket(...args) {
+    // reuseSocket(socket, req)
+    super.reuseSocket(...args);
+    const socket = args[0];
+    const req = args[1];
+    req.reusedSocket = true;
+    const agentTimeout = this.options.timeout;
+    if (getSocketTimeout(socket) !== agentTimeout) {
+      // reset timeout before use
+      socket.setTimeout(agentTimeout);
+      debug('%s reset timeout to %sms', socket[SOCKET_NAME], agentTimeout);
+    }
+    socket[SOCKET_REQUEST_COUNT]++;
+    debug('%s(requests: %s, finished: %s) reuse on addRequest, timeout %sms',
+      socket[SOCKET_NAME], socket[SOCKET_REQUEST_COUNT], socket[SOCKET_REQUEST_FINISHED_COUNT],
+      getSocketTimeout(socket));
+  }
+
+  [CREATE_ID]() {
+    const id = this[CURRENT_ID]++;
+    if (this[CURRENT_ID] === Number.MAX_SAFE_INTEGER) this[CURRENT_ID] = 0;
+    return id;
+  }
+
+  [INIT_SOCKET](socket, options) {
+    // bugfix here.
+    // https on node 8, 10 won't set agent.options.timeout by default
+    // TODO: need to fix on node itself
+    if (options.timeout) {
+      const timeout = getSocketTimeout(socket);
+      if (!timeout) {
+        socket.setTimeout(options.timeout);
+      }
+    }
+
+    if (this.options.keepAlive) {
+      // Disable Nagle's algorithm: http://blog.caustik.com/2012/04/08/scaling-node-js-to-100k-concurrent-connections/
+      // https://fengmk2.com/benchmark/nagle-algorithm-delayed-ack-mock.html
+      socket.setNoDelay(true);
+    }
+    this.createSocketCount++;
+    if (this.options.socketActiveTTL) {
+      socket[SOCKET_CREATED_TIME] = Date.now();
+    }
+    // don't show the hole '-----BEGIN CERTIFICATE----' key string
+    socket[SOCKET_NAME] = `sock[${this[CREATE_ID]()}#${options._agentKey}]`.split('-----BEGIN', 1)[0];
+    socket[SOCKET_REQUEST_COUNT] = 1;
+    socket[SOCKET_REQUEST_FINISHED_COUNT] = 0;
+    installListeners(this, socket, options);
+  }
+
+  createConnection(options, oncreate) {
+    let called = false;
+    const onNewCreate = (err, socket) => {
+      if (called) return;
+      called = true;
+
+      if (err) {
+        this.createSocketErrorCount++;
+        return oncreate(err);
+      }
+      this[INIT_SOCKET](socket, options);
+      oncreate(err, socket);
+    };
+
+    const newSocket = super.createConnection(options, onNewCreate);
+    if (newSocket) onNewCreate(null, newSocket);
+    return newSocket;
+  }
+
+  get statusChanged() {
+    const changed = this.createSocketCount !== this.createSocketCountLastCheck ||
+      this.createSocketErrorCount !== this.createSocketErrorCountLastCheck ||
+      this.closeSocketCount !== this.closeSocketCountLastCheck ||
+      this.errorSocketCount !== this.errorSocketCountLastCheck ||
+      this.timeoutSocketCount !== this.timeoutSocketCountLastCheck ||
+      this.requestCount !== this.requestCountLastCheck;
+    if (changed) {
+      this.createSocketCountLastCheck = this.createSocketCount;
+      this.createSocketErrorCountLastCheck = this.createSocketErrorCount;
+      this.closeSocketCountLastCheck = this.closeSocketCount;
+      this.errorSocketCountLastCheck = this.errorSocketCount;
+      this.timeoutSocketCountLastCheck = this.timeoutSocketCount;
+      this.requestCountLastCheck = this.requestCount;
+    }
+    return changed;
+  }
+
+  getCurrentStatus() {
+    return {
+      createSocketCount: this.createSocketCount,
+      createSocketErrorCount: this.createSocketErrorCount,
+      closeSocketCount: this.closeSocketCount,
+      errorSocketCount: this.errorSocketCount,
+      timeoutSocketCount: this.timeoutSocketCount,
+      requestCount: this.requestCount,
+      freeSockets: inspect(this.freeSockets),
+      sockets: inspect(this.sockets),
+      requests: inspect(this.requests),
+    };
+  }
+}
+
+// node 8 don't has timeout attribute on socket
+// https://github.com/nodejs/node/pull/21204/files#diff-e6ef024c3775d787c38487a6309e491dR408
+function getSocketTimeout(socket) {
+  return socket.timeout || socket._idleTimeout;
+}
+
+function installListeners(agent, socket, options) {
+  debug('%s create, timeout %sms', socket[SOCKET_NAME], getSocketTimeout(socket));
+
+  // listener socket events: close, timeout, error, free
+  function onFree() {
+    // create and socket.emit('free') logic
+    // https://github.com/nodejs/node/blob/master/lib/_http_agent.js#L311
+    // no req on the socket, it should be the new socket
+    if (!socket._httpMessage && socket[SOCKET_REQUEST_COUNT] === 1) return;
+
+    socket[SOCKET_REQUEST_FINISHED_COUNT]++;
+    agent.requestCount++;
+    debug('%s(requests: %s, finished: %s) free',
+      socket[SOCKET_NAME], socket[SOCKET_REQUEST_COUNT], socket[SOCKET_REQUEST_FINISHED_COUNT]);
+
+    // should reuse on pedding requests?
+    const name = agent.getName(options);
+    if (socket.writable && agent.requests[name] && agent.requests[name].length) {
+      // will be reuse on agent free listener
+      socket[SOCKET_REQUEST_COUNT]++;
+      debug('%s(requests: %s, finished: %s) will be reuse on agent free event',
+        socket[SOCKET_NAME], socket[SOCKET_REQUEST_COUNT], socket[SOCKET_REQUEST_FINISHED_COUNT]);
+    }
+  }
+  socket.on('free', onFree);
+
+  function onClose(isError) {
+    debug('%s(requests: %s, finished: %s) close, isError: %s',
+      socket[SOCKET_NAME], socket[SOCKET_REQUEST_COUNT], socket[SOCKET_REQUEST_FINISHED_COUNT], isError);
+    agent.closeSocketCount++;
+  }
+  socket.on('close', onClose);
+
+  // start socket timeout handler
+  function onTimeout() {
+    // onTimeout and emitRequestTimeout(_http_client.js)
+    // https://github.com/nodejs/node/blob/v12.x/lib/_http_client.js#L711
+    const listenerCount = socket.listeners('timeout').length;
+    // node <= 10, default listenerCount is 1, onTimeout
+    // 11 < node <= 12, default listenerCount is 2, onTimeout and emitRequestTimeout
+    // node >= 13, default listenerCount is 3, onTimeout,
+    //   onTimeout(https://github.com/nodejs/node/pull/32000/files#diff-5f7fb0850412c6be189faeddea6c5359R333)
+    //   and emitRequestTimeout
+    const timeout = getSocketTimeout(socket);
+    const req = socket._httpMessage;
+    const reqTimeoutListenerCount = req && req.listeners('timeout').length || 0;
+    debug('%s(requests: %s, finished: %s) timeout after %sms, listeners %s, defaultTimeoutListenerCount %s, hasHttpRequest %s, HttpRequest timeoutListenerCount %s',
+      socket[SOCKET_NAME], socket[SOCKET_REQUEST_COUNT], socket[SOCKET_REQUEST_FINISHED_COUNT],
+      timeout, listenerCount, defaultTimeoutListenerCount, !!req, reqTimeoutListenerCount);
+    if (debug.enabled) {
+      debug('timeout listeners: %s', socket.listeners('timeout').map(f => f.name).join(', '));
+    }
+    agent.timeoutSocketCount++;
+    const name = agent.getName(options);
+    if (agent.freeSockets[name] && agent.freeSockets[name].indexOf(socket) !== -1) {
+      // free socket timeout, destroy quietly
+      socket.destroy();
+      // Remove it from freeSockets list immediately to prevent new requests
+      // from being sent through this socket.
+      agent.removeSocket(socket, options);
+      debug('%s is free, destroy quietly', socket[SOCKET_NAME]);
+    } else {
+      // if there is no any request socket timeout handler,
+      // agent need to handle socket timeout itself.
+      //
+      // custom request socket timeout handle logic must follow these rules:
+      //  1. Destroy socket first
+      //  2. Must emit socket 'agentRemove' event tell agent remove socket
+      //     from freeSockets list immediately.
+      //     Otherise you may be get 'socket hang up' error when reuse
+      //     free socket and timeout happen in the same time.
+      if (reqTimeoutListenerCount === 0) {
+        const error = new Error('Socket timeout');
+        error.code = 'ERR_SOCKET_TIMEOUT';
+        error.timeout = timeout;
+        // must manually call socket.end() or socket.destroy() to end the connection.
+        // https://nodejs.org/dist/latest-v10.x/docs/api/net.html#net_socket_settimeout_timeout_callback
+        socket.destroy(error);
+        agent.removeSocket(socket, options);
+        debug('%s destroy with timeout error', socket[SOCKET_NAME]);
+      }
+    }
+  }
+  socket.on('timeout', onTimeout);
+
+  function onError(err) {
+    const listenerCount = socket.listeners('error').length;
+    debug('%s(requests: %s, finished: %s) error: %s, listenerCount: %s',
+      socket[SOCKET_NAME], socket[SOCKET_REQUEST_COUNT], socket[SOCKET_REQUEST_FINISHED_COUNT],
+      err, listenerCount);
+    agent.errorSocketCount++;
+    if (listenerCount === 1) {
+      // if socket don't contain error event handler, don't catch it, emit it again
+      debug('%s emit uncaught error event', socket[SOCKET_NAME]);
+      socket.removeListener('error', onError);
+      socket.emit('error', err);
+    }
+  }
+  socket.on('error', onError);
+
+  function onRemove() {
+    debug('%s(requests: %s, finished: %s) agentRemove',
+      socket[SOCKET_NAME],
+      socket[SOCKET_REQUEST_COUNT], socket[SOCKET_REQUEST_FINISHED_COUNT]);
+    // We need this function for cases like HTTP 'upgrade'
+    // (defined by WebSockets) where we need to remove a socket from the
+    // pool because it'll be locked up indefinitely
+    socket.removeListener('close', onClose);
+    socket.removeListener('error', onError);
+    socket.removeListener('free', onFree);
+    socket.removeListener('timeout', onTimeout);
+    socket.removeListener('agentRemove', onRemove);
+  }
+  socket.on('agentRemove', onRemove);
+}
+
+module.exports = Agent;
+
+function inspect(obj) {
+  const res = {};
+  for (const key in obj) {
+    res[key] = obj[key].length;
+  }
+  return res;
+}
diff --git a/server/node_modules/agentkeepalive/lib/constants.js b/server/node_modules/agentkeepalive/lib/constants.js
new file mode 100644
index 0000000..ca7ab97
--- /dev/null
+++ b/server/node_modules/agentkeepalive/lib/constants.js
@@ -0,0 +1,14 @@
+'use strict';
+
+module.exports = {
+  // agent
+  CURRENT_ID: Symbol('agentkeepalive#currentId'),
+  CREATE_ID: Symbol('agentkeepalive#createId'),
+  INIT_SOCKET: Symbol('agentkeepalive#initSocket'),
+  CREATE_HTTPS_CONNECTION: Symbol('agentkeepalive#createHttpsConnection'),
+  // socket
+  SOCKET_CREATED_TIME: Symbol('agentkeepalive#socketCreatedTime'),
+  SOCKET_NAME: Symbol('agentkeepalive#socketName'),
+  SOCKET_REQUEST_COUNT: Symbol('agentkeepalive#socketRequestCount'),
+  SOCKET_REQUEST_FINISHED_COUNT: Symbol('agentkeepalive#socketRequestFinishedCount'),
+};
diff --git a/server/node_modules/agentkeepalive/lib/https_agent.js b/server/node_modules/agentkeepalive/lib/https_agent.js
new file mode 100644
index 0000000..344fb32
--- /dev/null
+++ b/server/node_modules/agentkeepalive/lib/https_agent.js
@@ -0,0 +1,51 @@
+'use strict';
+
+const OriginalHttpsAgent = require('https').Agent;
+const HttpAgent = require('./agent');
+const {
+  INIT_SOCKET,
+  CREATE_HTTPS_CONNECTION,
+} = require('./constants');
+
+class HttpsAgent extends HttpAgent {
+  constructor(options) {
+    super(options);
+
+    this.defaultPort = 443;
+    this.protocol = 'https:';
+    this.maxCachedSessions = this.options.maxCachedSessions;
+    /* istanbul ignore next */
+    if (this.maxCachedSessions === undefined) {
+      this.maxCachedSessions = 100;
+    }
+
+    this._sessionCache = {
+      map: {},
+      list: [],
+    };
+  }
+
+  createConnection(options, oncreate) {
+    const socket = this[CREATE_HTTPS_CONNECTION](options, oncreate);
+    this[INIT_SOCKET](socket, options);
+    return socket;
+  }
+}
+
+// https://github.com/nodejs/node/blob/master/lib/https.js#L89
+HttpsAgent.prototype[CREATE_HTTPS_CONNECTION] = OriginalHttpsAgent.prototype.createConnection;
+
+[
+  'getName',
+  '_getSession',
+  '_cacheSession',
+  // https://github.com/nodejs/node/pull/4982
+  '_evictSession',
+].forEach(function(method) {
+  /* istanbul ignore next */
+  if (typeof OriginalHttpsAgent.prototype[method] === 'function') {
+    HttpsAgent.prototype[method] = OriginalHttpsAgent.prototype[method];
+  }
+});
+
+module.exports = HttpsAgent;
diff --git a/server/node_modules/agentkeepalive/package.json b/server/node_modules/agentkeepalive/package.json
new file mode 100644
index 0000000..e6fc7f0
--- /dev/null
+++ b/server/node_modules/agentkeepalive/package.json
@@ -0,0 +1,56 @@
+{
+  "name": "agentkeepalive",
+  "version": "4.6.0",
+  "description": "Missing keepalive http.Agent",
+  "main": "index.js",
+  "browser": "browser.js",
+  "files": [
+    "index.js",
+    "index.d.ts",
+    "browser.js",
+    "lib"
+  ],
+  "scripts": {
+    "contributor": "git-contributor",
+    "test": "npm run lint && egg-bin test --full-trace",
+    "test-local": "egg-bin test --full-trace",
+    "cov": "cross-env NODE_DEBUG=agentkeepalive egg-bin cov --full-trace",
+    "ci": "npm run lint && npm run cov",
+    "lint": "eslint lib test index.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/node-modules/agentkeepalive.git"
+  },
+  "bugs": {
+    "url": "https://github.com/node-modules/agentkeepalive/issues"
+  },
+  "keywords": [
+    "http",
+    "https",
+    "agent",
+    "keepalive",
+    "agentkeepalive",
+    "HttpAgent",
+    "HttpsAgent"
+  ],
+  "dependencies": {
+    "humanize-ms": "^1.2.1"
+  },
+  "devDependencies": {
+    "coffee": "^5.3.0",
+    "cross-env": "^6.0.3",
+    "egg-bin": "^4.9.0",
+    "eslint": "^5.7.0",
+    "eslint-config-egg": "^7.1.0",
+    "git-contributor": "^2.0.0",
+    "mm": "^2.4.1",
+    "pedding": "^1.1.0",
+    "typescript": "^3.8.3"
+  },
+  "engines": {
+    "node": ">= 8.0.0"
+  },
+  "author": "fengmk2 <fengmk2@gmail.com> (https://github.com/fengmk2)",
+  "license": "MIT"
+}
diff --git a/server/node_modules/aggregate-error/index.d.ts b/server/node_modules/aggregate-error/index.d.ts
new file mode 100644
index 0000000..502bf7a
--- /dev/null
+++ b/server/node_modules/aggregate-error/index.d.ts
@@ -0,0 +1,51 @@
+/**
+Create an error from multiple errors.
+*/
+declare class AggregateError<T extends Error = Error> extends Error implements Iterable<T> {
+	readonly name: 'AggregateError';
+
+	/**
+	@param errors - If a string, a new `Error` is created with the string as the error message. If a non-Error object, a new `Error` is created with all properties from the object copied over.
+	@returns An Error that is also an [`Iterable`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Iterators_and_Generators#Iterables) for the individual errors.
+
+	@example
+	```
+	import AggregateError = require('aggregate-error');
+
+	const error = new AggregateError([new Error('foo'), 'bar', {message: 'baz'}]);
+
+	throw error;
+
+	// AggregateError:
+	//	Error: foo
+	//		at Object.<anonymous> (/Users/sindresorhus/dev/aggregate-error/example.js:3:33)
+	//	Error: bar
+	//		at Object.<anonymous> (/Users/sindresorhus/dev/aggregate-error/example.js:3:13)
+	//	Error: baz
+	//		at Object.<anonymous> (/Users/sindresorhus/dev/aggregate-error/example.js:3:13)
+	//	at AggregateError (/Users/sindresorhus/dev/aggregate-error/index.js:19:3)
+	//	at Object.<anonymous> (/Users/sindresorhus/dev/aggregate-error/example.js:3:13)
+	//	at Module._compile (module.js:556:32)
+	//	at Object.Module._extensions..js (module.js:565:10)
+	//	at Module.load (module.js:473:32)
+	//	at tryModuleLoad (module.js:432:12)
+	//	at Function.Module._load (module.js:424:3)
+	//	at Module.runMain (module.js:590:10)
+	//	at run (bootstrap_node.js:394:7)
+	//	at startup (bootstrap_node.js:149:9)
+
+
+	for (const individualError of error) {
+		console.log(individualError);
+	}
+	//=> [Error: foo]
+	//=> [Error: bar]
+	//=> [Error: baz]
+	```
+	*/
+	constructor(errors: ReadonlyArray<T | {[key: string]: any} | string>);
+
+	[Symbol.iterator](): IterableIterator<T>;
+}
+
+export = AggregateError;
diff --git a/server/node_modules/aggregate-error/index.js b/server/node_modules/aggregate-error/index.js
new file mode 100644
index 0000000..ba5bf02
--- /dev/null
+++ b/server/node_modules/aggregate-error/index.js
@@ -0,0 +1,47 @@
+'use strict';
+const indentString = require('indent-string');
+const cleanStack = require('clean-stack');
+
+const cleanInternalStack = stack => stack.replace(/\s+at .*aggregate-error\/index.js:\d+:\d+\)?/g, '');
+
+class AggregateError extends Error {
+	constructor(errors) {
+		if (!Array.isArray(errors)) {
+			throw new TypeError(`Expected input to be an Array, got ${typeof errors}`);
+		}
+
+		errors = [...errors].map(error => {
+			if (error instanceof Error) {
+				return error;
+			}
+
+			if (error !== null && typeof error === 'object') {
+				// Handle plain error objects with message property and/or possibly other metadata
+				return Object.assign(new Error(error.message), error);
+			}
+
+			return new Error(error);
+		});
+
+		let message = errors
+			.map(error => {
+				// The `stack` property is not standardized, so we can't assume it exists
+				return typeof error.stack === 'string' ? cleanInternalStack(cleanStack(error.stack)) : String(error);
+			})
+			.join('\n');
+		message = '\n' + indentString(message, 4);
+		super(message);
+
+		this.name = 'AggregateError';
+
+		Object.defineProperty(this, '_errors', {value: errors});
+	}
+
+	* [Symbol.iterator]() {
+		for (const error of this._errors) {
+			yield error;
+		}
+	}
+}
+
+module.exports = AggregateError;
diff --git a/server/node_modules/aggregate-error/license b/server/node_modules/aggregate-error/license
new file mode 100644
index 0000000..e7af2f7
--- /dev/null
+++ b/server/node_modules/aggregate-error/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/aggregate-error/package.json b/server/node_modules/aggregate-error/package.json
new file mode 100644
index 0000000..74fcc37
--- /dev/null
+++ b/server/node_modules/aggregate-error/package.json
@@ -0,0 +1,41 @@
+{
+	"name": "aggregate-error",
+	"version": "3.1.0",
+	"description": "Create an error from multiple errors",
+	"license": "MIT",
+	"repository": "sindresorhus/aggregate-error",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=8"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"aggregate",
+		"error",
+		"combine",
+		"multiple",
+		"many",
+		"collection",
+		"iterable",
+		"iterator"
+	],
+	"dependencies": {
+		"clean-stack": "^2.0.0",
+		"indent-string": "^4.0.0"
+	},
+	"devDependencies": {
+		"ava": "^2.4.0",
+		"tsd": "^0.7.1",
+		"xo": "^0.25.3"
+	}
+}
diff --git a/server/node_modules/aggregate-error/readme.md b/server/node_modules/aggregate-error/readme.md
new file mode 100644
index 0000000..850de98
--- /dev/null
+++ b/server/node_modules/aggregate-error/readme.md
@@ -0,0 +1,61 @@
+# aggregate-error [![Build Status](https://travis-ci.org/sindresorhus/aggregate-error.svg?branch=master)](https://travis-ci.org/sindresorhus/aggregate-error)
+
+> Create an error from multiple errors
+
+
+## Install
+
+```
+$ npm install aggregate-error
+```
+
+
+## Usage
+
+```js
+const AggregateError = require('aggregate-error');
+
+const error = new AggregateError([new Error('foo'), 'bar', {message: 'baz'}]);
+
+throw error;
+/*
+AggregateError:
+    Error: foo
+        at Object.<anonymous> (/Users/sindresorhus/dev/aggregate-error/example.js:3:33)
+    Error: bar
+        at Object.<anonymous> (/Users/sindresorhus/dev/aggregate-error/example.js:3:13)
+    Error: baz
+        at Object.<anonymous> (/Users/sindresorhus/dev/aggregate-error/example.js:3:13)
+    at AggregateError (/Users/sindresorhus/dev/aggregate-error/index.js:19:3)
+    at Object.<anonymous> (/Users/sindresorhus/dev/aggregate-error/example.js:3:13)
+    at Module._compile (module.js:556:32)
+    at Object.Module._extensions..js (module.js:565:10)
+    at Module.load (module.js:473:32)
+    at tryModuleLoad (module.js:432:12)
+    at Function.Module._load (module.js:424:3)
+    at Module.runMain (module.js:590:10)
+    at run (bootstrap_node.js:394:7)
+    at startup (bootstrap_node.js:149:9)
+*/
+
+for (const individualError of error) {
+	console.log(individualError);
+}
+//=> [Error: foo]
+//=> [Error: bar]
+//=> [Error: baz]
+```
+
+
+## API
+
+### AggregateError(errors)
+
+Returns an `Error` that is also an [`Iterable`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Iterators_and_Generators#Iterables) for the individual errors.
+
+#### errors
+
+Type: `Array<Error|Object|string>`
+
+If a string, a new `Error` is created with the string as the error message.<br>
+If a non-Error object, a new `Error` is created with all properties from the object copied over.
diff --git a/server/node_modules/ansi-regex/index.d.ts b/server/node_modules/ansi-regex/index.d.ts
new file mode 100644
index 0000000..2dbf6af
--- /dev/null
+++ b/server/node_modules/ansi-regex/index.d.ts
@@ -0,0 +1,37 @@
+declare namespace ansiRegex {
+	interface Options {
+		/**
+		Match only the first ANSI escape.
+
+		@default false
+		*/
+		onlyFirst: boolean;
+	}
+}
+
+/**
+Regular expression for matching ANSI escape codes.
+
+@example
+```
+import ansiRegex = require('ansi-regex');
+
+ansiRegex().test('\u001B[4mcake\u001B[0m');
+//=> true
+
+ansiRegex().test('cake');
+//=> false
+
+'\u001B[4mcake\u001B[0m'.match(ansiRegex());
+//=> ['\u001B[4m', '\u001B[0m']
+
+'\u001B[4mcake\u001B[0m'.match(ansiRegex({onlyFirst: true}));
+//=> ['\u001B[4m']
+
+'\u001B]8;;https://github.com\u0007click\u001B]8;;\u0007'.match(ansiRegex());
+//=> ['\u001B]8;;https://github.com\u0007', '\u001B]8;;\u0007']
+```
+*/
+declare function ansiRegex(options?: ansiRegex.Options): RegExp;
+
+export = ansiRegex;
diff --git a/server/node_modules/ansi-regex/index.js b/server/node_modules/ansi-regex/index.js
new file mode 100644
index 0000000..616ff83
--- /dev/null
+++ b/server/node_modules/ansi-regex/index.js
@@ -0,0 +1,10 @@
+'use strict';
+
+module.exports = ({onlyFirst = false} = {}) => {
+	const pattern = [
+		'[\\u001B\\u009B][[\\]()#;?]*(?:(?:(?:(?:;[-a-zA-Z\\d\\/#&.:=?%@~_]+)*|[a-zA-Z\\d]+(?:;[-a-zA-Z\\d\\/#&.:=?%@~_]*)*)?\\u0007)',
+		'(?:(?:\\d{1,4}(?:;\\d{0,4})*)?[\\dA-PR-TZcf-ntqry=><~]))'
+	].join('|');
+
+	return new RegExp(pattern, onlyFirst ? undefined : 'g');
+};
diff --git a/server/node_modules/ansi-regex/license b/server/node_modules/ansi-regex/license
new file mode 100644
index 0000000..e7af2f7
--- /dev/null
+++ b/server/node_modules/ansi-regex/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/ansi-regex/package.json b/server/node_modules/ansi-regex/package.json
new file mode 100644
index 0000000..017f531
--- /dev/null
+++ b/server/node_modules/ansi-regex/package.json
@@ -0,0 +1,55 @@
+{
+	"name": "ansi-regex",
+	"version": "5.0.1",
+	"description": "Regular expression for matching ANSI escape codes",
+	"license": "MIT",
+	"repository": "chalk/ansi-regex",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=8"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd",
+		"view-supported": "node fixtures/view-codes.js"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"ansi",
+		"styles",
+		"color",
+		"colour",
+		"colors",
+		"terminal",
+		"console",
+		"cli",
+		"string",
+		"tty",
+		"escape",
+		"formatting",
+		"rgb",
+		"256",
+		"shell",
+		"xterm",
+		"command-line",
+		"text",
+		"regex",
+		"regexp",
+		"re",
+		"match",
+		"test",
+		"find",
+		"pattern"
+	],
+	"devDependencies": {
+		"ava": "^2.4.0",
+		"tsd": "^0.9.0",
+		"xo": "^0.25.3"
+	}
+}
diff --git a/server/node_modules/ansi-regex/readme.md b/server/node_modules/ansi-regex/readme.md
new file mode 100644
index 0000000..4d848bc
--- /dev/null
+++ b/server/node_modules/ansi-regex/readme.md
@@ -0,0 +1,78 @@
+# ansi-regex
+
+> Regular expression for matching [ANSI escape codes](https://en.wikipedia.org/wiki/ANSI_escape_code)
+
+
+## Install
+
+```
+$ npm install ansi-regex
+```
+
+
+## Usage
+
+```js
+const ansiRegex = require('ansi-regex');
+
+ansiRegex().test('\u001B[4mcake\u001B[0m');
+//=> true
+
+ansiRegex().test('cake');
+//=> false
+
+'\u001B[4mcake\u001B[0m'.match(ansiRegex());
+//=> ['\u001B[4m', '\u001B[0m']
+
+'\u001B[4mcake\u001B[0m'.match(ansiRegex({onlyFirst: true}));
+//=> ['\u001B[4m']
+
+'\u001B]8;;https://github.com\u0007click\u001B]8;;\u0007'.match(ansiRegex());
+//=> ['\u001B]8;;https://github.com\u0007', '\u001B]8;;\u0007']
+```
+
+
+## API
+
+### ansiRegex(options?)
+
+Returns a regex for matching ANSI escape codes.
+
+#### options
+
+Type: `object`
+
+##### onlyFirst
+
+Type: `boolean`<br>
+Default: `false` *(Matches any ANSI escape codes in a string)*
+
+Match only the first ANSI escape.
+
+
+## FAQ
+
+### Why do you test for codes not in the ECMA 48 standard?
+
+Some of the codes we run as a test are codes that we acquired finding various lists of non-standard or manufacturer specific codes. We test for both standard and non-standard codes, as most of them follow the same or similar format and can be safely matched in strings without the risk of removing actual string content. There are a few non-standard control codes that do not follow the traditional format (i.e. they end in numbers) thus forcing us to exclude them from the test because we cannot reliably match them.
+
+On the historical side, those ECMA standards were established in the early 90's whereas the VT100, for example, was designed in the mid/late 70's. At that point in time, control codes were still pretty ungoverned and engineers used them for a multitude of things, namely to activate hardware ports that may have been proprietary. Somewhere else you see a similar 'anarchy' of codes is in the x86 architecture for processors; there are a ton of "interrupts" that can mean different things on certain brands of processors, most of which have been phased out.
+
+
+## Maintainers
+
+- [Sindre Sorhus](https://github.com/sindresorhus)
+- [Josh Junon](https://github.com/qix-)
+
+
+---
+
+<div align="center">
+	<b>
+		<a href="https://tidelift.com/subscription/pkg/npm-ansi-regex?utm_source=npm-ansi-regex&utm_medium=referral&utm_campaign=readme">Get professional support for this package with a Tidelift subscription</a>
+	</b>
+	<br>
+	<sub>
+		Tidelift helps make open source sustainable for maintainers while giving companies<br>assurances about security, maintenance, and licensing for their dependencies.
+	</sub>
+</div>
diff --git a/server/node_modules/append-field/.npmignore b/server/node_modules/append-field/.npmignore
new file mode 100644
index 0000000..c2658d7
--- /dev/null
+++ b/server/node_modules/append-field/.npmignore
@@ -0,0 +1 @@
+node_modules/
diff --git a/server/node_modules/append-field/LICENSE b/server/node_modules/append-field/LICENSE
new file mode 100644
index 0000000..14b1f89
--- /dev/null
+++ b/server/node_modules/append-field/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 Linus Unnebäck
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/append-field/README.md b/server/node_modules/append-field/README.md
new file mode 100644
index 0000000..62b901b
--- /dev/null
+++ b/server/node_modules/append-field/README.md
@@ -0,0 +1,44 @@
+# `append-field`
+
+A [W3C HTML JSON forms spec](http://www.w3.org/TR/html-json-forms/) compliant
+field appender (for lack of a better name). Useful for people implementing
+`application/x-www-form-urlencoded` and `multipart/form-data` parsers.
+
+It works best on objects created with `Object.create(null)`. Otherwise it might
+conflict with variables from the prototype (e.g. `hasOwnProperty`).
+
+## Installation
+
+```sh
+npm install --save append-field
+```
+
+## Usage
+
+```javascript
+var appendField = require('append-field')
+var obj = Object.create(null)
+
+appendField(obj, 'pets[0][species]', 'Dahut')
+appendField(obj, 'pets[0][name]', 'Hypatia')
+appendField(obj, 'pets[1][species]', 'Felis Stultus')
+appendField(obj, 'pets[1][name]', 'Billie')
+
+console.log(obj)
+```
+
+```text
+{ pets:
+   [ { species: 'Dahut', name: 'Hypatia' },
+     { species: 'Felis Stultus', name: 'Billie' } ] }
+```
+
+## API
+
+### `appendField(store, key, value)`
+
+Adds the field named `key` with the value `value` to the object `store`.
+
+## License
+
+MIT
diff --git a/server/node_modules/append-field/index.js b/server/node_modules/append-field/index.js
new file mode 100644
index 0000000..fc5acc8
--- /dev/null
+++ b/server/node_modules/append-field/index.js
@@ -0,0 +1,12 @@
+var parsePath = require('./lib/parse-path')
+var setValue = require('./lib/set-value')
+
+function appendField (store, key, value) {
+  var steps = parsePath(key)
+
+  steps.reduce(function (context, step) {
+    return setValue(context, step, context[step.key], value)
+  }, store)
+}
+
+module.exports = appendField
diff --git a/server/node_modules/append-field/lib/parse-path.js b/server/node_modules/append-field/lib/parse-path.js
new file mode 100644
index 0000000..31d6179
--- /dev/null
+++ b/server/node_modules/append-field/lib/parse-path.js
@@ -0,0 +1,53 @@
+var reFirstKey = /^[^\[]*/
+var reDigitPath = /^\[(\d+)\]/
+var reNormalPath = /^\[([^\]]+)\]/
+
+function parsePath (key) {
+  function failure () {
+    return [{ type: 'object', key: key, last: true }]
+  }
+
+  var firstKey = reFirstKey.exec(key)[0]
+  if (!firstKey) return failure()
+
+  var len = key.length
+  var pos = firstKey.length
+  var tail = { type: 'object', key: firstKey }
+  var steps = [tail]
+
+  while (pos < len) {
+    var m
+
+    if (key[pos] === '[' && key[pos + 1] === ']') {
+      pos += 2
+      tail.append = true
+      if (pos !== len) return failure()
+      continue
+    }
+
+    m = reDigitPath.exec(key.substring(pos))
+    if (m !== null) {
+      pos += m[0].length
+      tail.nextType = 'array'
+      tail = { type: 'array', key: parseInt(m[1], 10) }
+      steps.push(tail)
+      continue
+    }
+
+    m = reNormalPath.exec(key.substring(pos))
+    if (m !== null) {
+      pos += m[0].length
+      tail.nextType = 'object'
+      tail = { type: 'object', key: m[1] }
+      steps.push(tail)
+      continue
+    }
+
+    return failure()
+  }
+
+  tail.last = true
+  return steps
+}
+
+module.exports = parsePath
diff --git a/server/node_modules/append-field/lib/set-value.js b/server/node_modules/append-field/lib/set-value.js
new file mode 100644
index 0000000..c15e873
--- /dev/null
+++ b/server/node_modules/append-field/lib/set-value.js
@@ -0,0 +1,64 @@
+function valueType (value) {
+  if (value === undefined) return 'undefined'
+  if (Array.isArray(value)) return 'array'
+  if (typeof value === 'object') return 'object'
+  return 'scalar'
+}
+
+function setLastValue (context, step, currentValue, entryValue) {
+  switch (valueType(currentValue)) {
+    case 'undefined':
+      if (step.append) {
+        context[step.key] = [entryValue]
+      } else {
+        context[step.key] = entryValue
+      }
+      break
+    case 'array':
+      context[step.key].push(entryValue)
+      break
+    case 'object':
+      return setLastValue(currentValue, { type: 'object', key: '', last: true }, currentValue[''], entryValue)
+    case 'scalar':
+      context[step.key] = [context[step.key], entryValue]
+      break
+  }
+
+  return context
+}
+
+function setValue (context, step, currentValue, entryValue) {
+  if (step.last) return setLastValue(context, step, currentValue, entryValue)
+
+  var obj
+  switch (valueType(currentValue)) {
+    case 'undefined':
+      if (step.nextType === 'array') {
+        context[step.key] = []
+      } else {
+        context[step.key] = Object.create(null)
+      }
+      return context[step.key]
+    case 'object':
+      return context[step.key]
+    case 'array':
+      if (step.nextType === 'array') {
+        return currentValue
+      }
+
+      obj = Object.create(null)
+      context[step.key] = obj
+      currentValue.forEach(function (item, i) {
+        if (item !== undefined) obj['' + i] = item
+      })
+
+      return obj
+    case 'scalar':
+      obj = Object.create(null)
+      obj[''] = currentValue
+      context[step.key] = obj
+      return obj
+  }
+}
+
+module.exports = setValue
diff --git a/server/node_modules/append-field/package.json b/server/node_modules/append-field/package.json
new file mode 100644
index 0000000..8d6e716
--- /dev/null
+++ b/server/node_modules/append-field/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "append-field",
+  "version": "1.0.0",
+  "license": "MIT",
+  "author": "Linus Unnebäck <linus@folkdatorn.se>",
+  "main": "index.js",
+  "devDependencies": {
+    "mocha": "^2.2.4",
+    "standard": "^6.0.5",
+    "testdata-w3c-json-form": "^0.2.0"
+  },
+  "scripts": {
+    "test": "standard && mocha"
+  },
+  "repository": {
+    "type": "git",
+    "url": "http://github.com/LinusU/node-append-field.git"
+  }
+}
diff --git a/server/node_modules/append-field/test/forms.js b/server/node_modules/append-field/test/forms.js
new file mode 100644
index 0000000..dd6fbc9
--- /dev/null
+++ b/server/node_modules/append-field/test/forms.js
@@ -0,0 +1,19 @@
+/* eslint-env mocha */
+
+var assert = require('assert')
+var appendField = require('../')
+var testData = require('testdata-w3c-json-form')
+
+describe('Append Field', function () {
+  for (var test of testData) {
+    it('handles ' + test.name, function () {
+      var store = Object.create(null)
+
+      for (var field of test.fields) {
+        appendField(store, field.key, field.value)
+      }
+
+      assert.deepEqual(store, test.expected)
+    })
+  }
+})
diff --git a/server/node_modules/aproba/LICENSE b/server/node_modules/aproba/LICENSE
new file mode 100644
index 0000000..f4be44d
--- /dev/null
+++ b/server/node_modules/aproba/LICENSE
@@ -0,0 +1,14 @@
+Copyright (c) 2015, Rebecca Turner <me@re-becca.org>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
diff --git a/server/node_modules/aproba/README.md b/server/node_modules/aproba/README.md
new file mode 100644
index 0000000..0bfc594
--- /dev/null
+++ b/server/node_modules/aproba/README.md
@@ -0,0 +1,94 @@
+aproba
+======
+
+A ridiculously light-weight function argument validator
+
+```
+var validate = require("aproba")
+
+function myfunc(a, b, c) {
+  // `a` must be a string, `b` a number, `c` a function
+  validate('SNF', arguments) // [a,b,c] is also valid
+}
+
+myfunc('test', 23, function () {}) // ok
+myfunc(123, 23, function () {}) // type error
+myfunc('test', 23) // missing arg error
+myfunc('test', 23, function () {}, true) // too many args error
+
+```
+
+Valid types are:
+
+| type | description
+| :--: | :----------
+| *    | matches any type
+| A    | `Array.isArray` OR an `arguments` object
+| S    | typeof == string
+| N    | typeof == number
+| F    | typeof == function
+| O    | typeof == object and not type A and not type E
+| B    | typeof == boolean
+| E    | `instanceof Error` OR `null` **(special: see below)**
+| Z    | == `null`
+
+Validation failures throw one of three exception types, distinguished by a
+`code` property of `EMISSINGARG`, `EINVALIDTYPE` or `ETOOMANYARGS`.
+
+If you pass in an invalid type then it will throw with a code of
+`EUNKNOWNTYPE`.
+
+If an **error** argument is found and is not null then the remaining
+arguments are optional.  That is, if you say `ESO` then that's like using a
+non-magical `E` in: `E|ESO|ZSO`.
+
+### But I have optional arguments?!
+
+You can provide more than one signature by separating them with pipes `|`.
+If any signature matches the arguments then they'll be considered valid.
+
+So for example, say you wanted to write a signature for
+`fs.createWriteStream`.  The docs for it describe it thusly:
+
+```
+fs.createWriteStream(path[, options])
+```
+
+This would be a signature of `SO|S`.  That is, a string and and object, or
+just a string.
+
+Now, if you read the full `fs` docs, you'll see that actually path can ALSO
+be a buffer.  And options can be a string, that is:
+```
+path <String> | <Buffer>
+options <String> | <Object>
+```
+
+To reproduce this you have to fully enumerate all of the possible
+combinations and that implies a signature of `SO|SS|OO|OS|S|O`.  The
+awkwardness is a feature: It reminds you of the complexity you're adding to
+your API when you do this sort of thing.
+
+
+### Browser support
+
+This has no dependencies and should work in browsers, though you'll have
+noisier stack traces.
+
+### Why this exists
+
+I wanted a very simple argument validator. It needed to do two things:
+
+1. Be more concise and easier to use than assertions
+
+2. Not encourage an infinite bikeshed of DSLs
+
+This is why types are specified by a single character and there's no such
+thing as an optional argument. 
+
+This is not intended to validate user data. This is specifically about
+asserting the interface of your functions.
+
+If you need greater validation, I encourage you to write them by hand or
+look elsewhere.
+
diff --git a/server/node_modules/aproba/index.js b/server/node_modules/aproba/index.js
new file mode 100644
index 0000000..5a58e81
--- /dev/null
+++ b/server/node_modules/aproba/index.js
@@ -0,0 +1,105 @@
+'use strict'
+module.exports = validate
+
+function isArguments (thingy) {
+  return thingy != null && typeof thingy === 'object' && thingy.hasOwnProperty('callee')
+}
+
+const types = {
+  '*': {label: 'any', check: () => true},
+  A: {label: 'array', check: _ => Array.isArray(_) || isArguments(_)},
+  S: {label: 'string', check: _ => typeof _ === 'string'},
+  N: {label: 'number', check: _ => typeof _ === 'number'},
+  F: {label: 'function', check: _ => typeof _ === 'function'},
+  O: {label: 'object', check: _ => typeof _ === 'object' && _ != null && !types.A.check(_) && !types.E.check(_)},
+  B: {label: 'boolean', check: _ => typeof _ === 'boolean'},
+  E: {label: 'error', check: _ => _ instanceof Error},
+  Z: {label: 'null', check: _ => _ == null}
+}
+
+function addSchema (schema, arity) {
+  const group = arity[schema.length] = arity[schema.length] || []
+  if (group.indexOf(schema) === -1) group.push(schema)
+}
+
+function validate (rawSchemas, args) {
+  if (arguments.length !== 2) throw wrongNumberOfArgs(['SA'], arguments.length)
+  if (!rawSchemas) throw missingRequiredArg(0, 'rawSchemas')
+  if (!args) throw missingRequiredArg(1, 'args')
+  if (!types.S.check(rawSchemas)) throw invalidType(0, ['string'], rawSchemas)
+  if (!types.A.check(args)) throw invalidType(1, ['array'], args)
+  const schemas = rawSchemas.split('|')
+  const arity = {}
+
+  schemas.forEach(schema => {
+    for (let ii = 0; ii < schema.length; ++ii) {
+      const type = schema[ii]
+      if (!types[type]) throw unknownType(ii, type)
+    }
+    if (/E.*E/.test(schema)) throw moreThanOneError(schema)
+    addSchema(schema, arity)
+    if (/E/.test(schema)) {
+      addSchema(schema.replace(/E.*$/, 'E'), arity)
+      addSchema(schema.replace(/E/, 'Z'), arity)
+      if (schema.length === 1) addSchema('', arity)
+    }
+  })
+  let matching = arity[args.length]
+  if (!matching) {
+    throw wrongNumberOfArgs(Object.keys(arity), args.length)
+  }
+  for (let ii = 0; ii < args.length; ++ii) {
+    let newMatching = matching.filter(schema => {
+      const type = schema[ii]
+      const typeCheck = types[type].check
+      return typeCheck(args[ii])
+    })
+    if (!newMatching.length) {
+      const labels = matching.map(_ => types[_[ii]].label).filter(_ => _ != null)
+      throw invalidType(ii, labels, args[ii])
+    }
+    matching = newMatching
+  }
+}
+
+function missingRequiredArg (num) {
+  return newException('EMISSINGARG', 'Missing required argument #' + (num + 1))
+}
+
+function unknownType (num, type) {
+  return newException('EUNKNOWNTYPE', 'Unknown type ' + type + ' in argument #' + (num + 1))
+}
+
+function invalidType (num, expectedTypes, value) {
+  let valueType
+  Object.keys(types).forEach(typeCode => {
+    if (types[typeCode].check(value)) valueType = types[typeCode].label
+  })
+  return newException('EINVALIDTYPE', 'Argument #' + (num + 1) + ': Expected ' +
+    englishList(expectedTypes) + ' but got ' + valueType)
+}
+
+function englishList (list) {
+  return list.join(', ').replace(/, ([^,]+)$/, ' or $1')
+}
+
+function wrongNumberOfArgs (expected, got) {
+  const english = englishList(expected)
+  const args = expected.every(ex => ex.length === 1)
+    ? 'argument'
+    : 'arguments'
+  return newException('EWRONGARGCOUNT', 'Expected ' + english + ' ' + args + ' but got ' + got)
+}
+
+function moreThanOneError (schema) {
+  return newException('ETOOMANYERRORTYPES',
+    'Only one error type per argument signature is allowed, more than one found in "' + schema + '"')
+}
+
+function newException (code, msg) {
+  const err = new TypeError(msg)
+  err.code = code
+  /* istanbul ignore else */
+  if (Error.captureStackTrace) Error.captureStackTrace(err, validate)
+  return err
+}
diff --git a/server/node_modules/aproba/package.json b/server/node_modules/aproba/package.json
new file mode 100644
index 0000000..71c7fca
--- /dev/null
+++ b/server/node_modules/aproba/package.json
@@ -0,0 +1,35 @@
+{
+  "name": "aproba",
+  "version": "2.1.0",
+  "description": "A ridiculously light-weight argument validator (now browser friendly)",
+  "main": "index.js",
+  "directories": {
+    "test": "test"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "standard": "^11.0.1",
+    "tap": "^12.0.1"
+  },
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "pretest": "standard",
+    "test": "tap --100 -J test/*.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/iarna/aproba"
+  },
+  "keywords": [
+    "argument",
+    "validate"
+  ],
+  "author": "Rebecca Turner <me@re-becca.org>",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/iarna/aproba/issues"
+  },
+  "homepage": "https://github.com/iarna/aproba"
+}
diff --git a/server/node_modules/are-we-there-yet/LICENSE.md b/server/node_modules/are-we-there-yet/LICENSE.md
new file mode 100644
index 0000000..845be76
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/LICENSE.md
@@ -0,0 +1,18 @@
+ISC License
+
+Copyright npm, Inc.
+
+Permission to use, copy, modify, and/or distribute this
+software for any purpose with or without fee is hereby
+granted, provided that the above copyright notice and this
+permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND NPM DISCLAIMS ALL
+WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+EVENT SHALL NPM BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/are-we-there-yet/README.md b/server/node_modules/are-we-there-yet/README.md
new file mode 100644
index 0000000..caae19b
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/README.md
@@ -0,0 +1,208 @@
+are-we-there-yet
+----------------
+
+Track complex hierarchies of asynchronous task completion statuses.  This is
+intended to give you a way of recording and reporting the progress of the big
+recursive fan-out and gather type workflows that are so common in async.
+
+What you do with this completion data is up to you, but the most common use case is to
+feed it to one of the many progress bar modules.
+
+Most progress bar modules include a rudimentary version of this, but my
+needs were more complex.
+
+Usage
+=====
+
+```javascript
+var TrackerGroup = require("are-we-there-yet").TrackerGroup
+
+var top = new TrackerGroup("program")
+
+var single = top.newItem("one thing", 100)
+single.completeWork(20)
+
+console.log(top.completed()) // 0.2
+
+fs.stat("file", function(er, stat) {
+  if (er) throw er  
+  var stream = top.newStream("file", stat.size)
+  console.log(top.completed()) // now 0.1 as single is 50% of the job and is 20% complete
+                              // and 50% * 20% == 10%
+  fs.createReadStream("file").pipe(stream).on("data", function (chunk) {
+    // do stuff with chunk
+  })
+  top.on("change", function (name) {
+    // called each time a chunk is read from "file"
+    // top.completed() will start at 0.1 and fill up to 0.6 as the file is read
+  })
+})
+```
+
+Shared Methods
+==============
+
+* var completed = tracker.completed()
+
+Implemented in: `Tracker`, `TrackerGroup`, `TrackerStream`
+
+Returns the ratio of completed work to work to be done. Range of 0 to 1.
+
+* tracker.finish()
+
+Implemented in: `Tracker`, `TrackerGroup`
+
+Marks the tracker as completed. With a TrackerGroup this marks all of its
+components as completed.
+
+Marks all of the components of this tracker as finished, which in turn means
+that `tracker.completed()` for this will now be 1.
+
+This will result in one or more `change` events being emitted.
+
+Events
+======
+
+All tracker objects emit `change` events with the following arguments:
+
+```
+function (name, completed, tracker)
+```
+
+`name` is the name of the tracker that originally emitted the event,
+or if it didn't have one, the first containing tracker group that had one.
+
+`completed` is the percent complete (as returned by `tracker.completed()` method).
+
+`tracker` is the tracker object that you are listening for events on.
+
+TrackerGroup
+============
+
+* var tracker = new TrackerGroup(**name**)
+
+  * **name** *(optional)* - The name of this tracker group, used in change
+    notifications if the component updating didn't have a name. Defaults to undefined.
+
+Creates a new empty tracker aggregation group. These are trackers whose
+completion status is determined by the completion status of other trackers added to this aggregation group.
+
+Ex.
+
+```javascript
+var tracker = new TrackerGroup("parent")
+var foo = tracker.newItem("firstChild", 100)
+var bar = tracker.newItem("secondChild", 100)
+
+foo.finish()
+console.log(tracker.completed()) // 0.5
+bar.finish()
+console.log(tracker.completed()) // 1
+```
+
+* tracker.addUnit(**otherTracker**, **weight**)
+
+  * **otherTracker** - Any of the other are-we-there-yet tracker objects
+  * **weight** *(optional)* - The weight to give the tracker, defaults to 1.
+
+Adds the **otherTracker** to this aggregation group. The weight determines
+how long you expect this tracker to take to complete in proportion to other
+units.  So for instance, if you add one tracker with a weight of 1 and
+another with a weight of 2, you're saying the second will take twice as long
+to complete as the first.  As such, the first will account for 33% of the
+completion of this tracker and the second will account for the other 67%.
+
+Returns **otherTracker**.
+
+* var subGroup = tracker.newGroup(**name**, **weight**)
+
+The above is exactly equivalent to:
+
+```javascript
+  var subGroup = tracker.addUnit(new TrackerGroup(name), weight)
+```
+
+* var subItem = tracker.newItem(**name**, **todo**, **weight**)
+
+The above is exactly equivalent to:
+
+```javascript
+  var subItem = tracker.addUnit(new Tracker(name, todo), weight)
+```
+
+* var subStream = tracker.newStream(**name**, **todo**, **weight**)
+
+The above is exactly equivalent to:
+
+```javascript
+  var subStream = tracker.addUnit(new TrackerStream(name, todo), weight)
+```
+
+* console.log( tracker.debug() )
+
+Returns a tree showing the completion of this tracker group and all of its
+children, including recursively entering all of the children.
+
+Tracker
+=======
+
+* var tracker = new Tracker(**name**, **todo**)
+
+  * **name** *(optional)* The name of this counter to report in change
+    events.  Defaults to undefined.
+  * **todo** *(optional)* The amount of work todo (a number). Defaults to 0.
+
+Ordinarily these are constructed as a part of a tracker group (via
+`newItem`).
+
+* var completed = tracker.completed()
+
+Returns the ratio of completed work to work to be done. Range of 0 to 1. If
+total work to be done is 0 then it will return 0.
+
+* tracker.addWork(**todo**)
+
+  * **todo** A number to add to the amount of work to be done.
+
+Increases the amount of work to be done, thus decreasing the completion
+percentage.  Triggers a `change` event.
+
+* tracker.completeWork(**completed**)
+
+  * **completed** A number to add to the work complete
+
+Increase the amount of work complete, thus increasing the completion percentage.
+Will never increase the work completed past the amount of work todo. That is,
+percentages > 100% are not allowed. Triggers a `change` event.
+
+* tracker.finish()
+
+Marks this tracker as finished, tracker.completed() will now be 1. Triggers
+a `change` event.
+
+TrackerStream
+=============
+
+* var tracker = new TrackerStream(**name**, **size**, **options**)
+
+  * **name** *(optional)* The name of this counter to report in change
+    events.  Defaults to undefined.
+  * **size** *(optional)* The number of bytes being sent through this stream.
+  * **options** *(optional)* A hash of stream options
+
+The tracker stream object is a pass through stream that updates an internal
+tracker object each time a block passes through.  It's intended to track
+downloads, file extraction and other related activities. You use it by piping
+your data source into it and then using it as your data source.
+
+If your data has a length attribute then that's used as the amount of work
+completed when the chunk is passed through.  If it does not (eg, object
+streams) then each chunk counts as completing 1 unit of work, so your size
+should be the total number of objects being streamed.
+
+* tracker.addWork(**todo**)
+
+  * **todo** Increase the expected overall size by **todo** bytes.
+
+Increases the amount of work to be done, thus decreasing the completion
+percentage.  Triggers a `change` event.
diff --git a/server/node_modules/are-we-there-yet/lib/index.js b/server/node_modules/are-we-there-yet/lib/index.js
new file mode 100644
index 0000000..57d8743
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/lib/index.js
@@ -0,0 +1,4 @@
+'use strict'
+exports.TrackerGroup = require('./tracker-group.js')
+exports.Tracker = require('./tracker.js')
+exports.TrackerStream = require('./tracker-stream.js')
diff --git a/server/node_modules/are-we-there-yet/lib/tracker-base.js b/server/node_modules/are-we-there-yet/lib/tracker-base.js
new file mode 100644
index 0000000..6f43687
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/lib/tracker-base.js
@@ -0,0 +1,11 @@
+'use strict'
+var EventEmitter = require('events').EventEmitter
+var util = require('util')
+
+var trackerId = 0
+var TrackerBase = module.exports = function (name) {
+  EventEmitter.call(this)
+  this.id = ++trackerId
+  this.name = name
+}
+util.inherits(TrackerBase, EventEmitter)
diff --git a/server/node_modules/are-we-there-yet/lib/tracker-group.js b/server/node_modules/are-we-there-yet/lib/tracker-group.js
new file mode 100644
index 0000000..a3c7af8
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/lib/tracker-group.js
@@ -0,0 +1,116 @@
+'use strict'
+var util = require('util')
+var TrackerBase = require('./tracker-base.js')
+var Tracker = require('./tracker.js')
+var TrackerStream = require('./tracker-stream.js')
+
+var TrackerGroup = module.exports = function (name) {
+  TrackerBase.call(this, name)
+  this.parentGroup = null
+  this.trackers = []
+  this.completion = {}
+  this.weight = {}
+  this.totalWeight = 0
+  this.finished = false
+  this.bubbleChange = bubbleChange(this)
+}
+util.inherits(TrackerGroup, TrackerBase)
+
+function bubbleChange (trackerGroup) {
+  return function (name, completed, tracker) {
+    trackerGroup.completion[tracker.id] = completed
+    if (trackerGroup.finished) {
+      return
+    }
+    trackerGroup.emit('change', name || trackerGroup.name, trackerGroup.completed(), trackerGroup)
+  }
+}
+
+TrackerGroup.prototype.nameInTree = function () {
+  var names = []
+  var from = this
+  while (from) {
+    names.unshift(from.name)
+    from = from.parentGroup
+  }
+  return names.join('/')
+}
+
+TrackerGroup.prototype.addUnit = function (unit, weight) {
+  if (unit.addUnit) {
+    var toTest = this
+    while (toTest) {
+      if (unit === toTest) {
+        throw new Error(
+          'Attempted to add tracker group ' +
+          unit.name + ' to tree that already includes it ' +
+          this.nameInTree(this))
+      }
+      toTest = toTest.parentGroup
+    }
+    unit.parentGroup = this
+  }
+  this.weight[unit.id] = weight || 1
+  this.totalWeight += this.weight[unit.id]
+  this.trackers.push(unit)
+  this.completion[unit.id] = unit.completed()
+  unit.on('change', this.bubbleChange)
+  if (!this.finished) {
+    this.emit('change', unit.name, this.completion[unit.id], unit)
+  }
+  return unit
+}
+
+TrackerGroup.prototype.completed = function () {
+  if (this.trackers.length === 0) {
+    return 0
+  }
+  var valPerWeight = 1 / this.totalWeight
+  var completed = 0
+  for (var ii = 0; ii < this.trackers.length; ii++) {
+    var trackerId = this.trackers[ii].id
+    completed +=
+      valPerWeight * this.weight[trackerId] * this.completion[trackerId]
+  }
+  return completed
+}
+
+TrackerGroup.prototype.newGroup = function (name, weight) {
+  return this.addUnit(new TrackerGroup(name), weight)
+}
+
+TrackerGroup.prototype.newItem = function (name, todo, weight) {
+  return this.addUnit(new Tracker(name, todo), weight)
+}
+
+TrackerGroup.prototype.newStream = function (name, todo, weight) {
+  return this.addUnit(new TrackerStream(name, todo), weight)
+}
+
+TrackerGroup.prototype.finish = function () {
+  this.finished = true
+  if (!this.trackers.length) {
+    this.addUnit(new Tracker(), 1, true)
+  }
+  for (var ii = 0; ii < this.trackers.length; ii++) {
+    var tracker = this.trackers[ii]
+    tracker.finish()
+    tracker.removeListener('change', this.bubbleChange)
+  }
+  this.emit('change', this.name, 1, this)
+}
+
+var buffer = '                                  '
+TrackerGroup.prototype.debug = function (depth) {
+  depth = depth || 0
+  var indent = depth ? buffer.slice(0, depth) : ''
+  var output = indent + (this.name || 'top') + ': ' + this.completed() + '\n'
+  this.trackers.forEach(function (tracker) {
+    if (tracker instanceof TrackerGroup) {
+      output += tracker.debug(depth + 1)
+    } else {
+      output += indent + ' ' + tracker.name + ': ' + tracker.completed() + '\n'
+    }
+  })
+  return output
+}
diff --git a/server/node_modules/are-we-there-yet/lib/tracker-stream.js b/server/node_modules/are-we-there-yet/lib/tracker-stream.js
new file mode 100644
index 0000000..e1cf850
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/lib/tracker-stream.js
@@ -0,0 +1,36 @@
+'use strict'
+var util = require('util')
+var stream = require('readable-stream')
+var delegate = require('delegates')
+var Tracker = require('./tracker.js')
+
+var TrackerStream = module.exports = function (name, size, options) {
+  stream.Transform.call(this, options)
+  this.tracker = new Tracker(name, size)
+  this.name = name
+  this.id = this.tracker.id
+  this.tracker.on('change', delegateChange(this))
+}
+util.inherits(TrackerStream, stream.Transform)
+
+function delegateChange (trackerStream) {
+  return function (name, completion, tracker) {
+    trackerStream.emit('change', name, completion, trackerStream)
+  }
+}
+
+TrackerStream.prototype._transform = function (data, encoding, cb) {
+  this.tracker.completeWork(data.length ? data.length : 1)
+  this.push(data)
+  cb()
+}
+
+TrackerStream.prototype._flush = function (cb) {
+  this.tracker.finish()
+  cb()
+}
+
+delegate(TrackerStream.prototype, 'tracker')
+  .method('completed')
+  .method('addWork')
+  .method('finish')
diff --git a/server/node_modules/are-we-there-yet/lib/tracker.js b/server/node_modules/are-we-there-yet/lib/tracker.js
new file mode 100644
index 0000000..a8f8b3b
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/lib/tracker.js
@@ -0,0 +1,32 @@
+'use strict'
+var util = require('util')
+var TrackerBase = require('./tracker-base.js')
+
+var Tracker = module.exports = function (name, todo) {
+  TrackerBase.call(this, name)
+  this.workDone = 0
+  this.workTodo = todo || 0
+}
+util.inherits(Tracker, TrackerBase)
+
+Tracker.prototype.completed = function () {
+  return this.workTodo === 0 ? 0 : this.workDone / this.workTodo
+}
+
+Tracker.prototype.addWork = function (work) {
+  this.workTodo += work
+  this.emit('change', this.name, this.completed(), this)
+}
+
+Tracker.prototype.completeWork = function (work) {
+  this.workDone += work
+  if (this.workDone > this.workTodo) {
+    this.workDone = this.workTodo
+  }
+  this.emit('change', this.name, this.completed(), this)
+}
+
+Tracker.prototype.finish = function () {
+  this.workTodo = this.workDone = 1
+  this.emit('change', this.name, 1, this)
+}
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/CONTRIBUTING.md b/server/node_modules/are-we-there-yet/node_modules/readable-stream/CONTRIBUTING.md
new file mode 100644
index 0000000..f478d58
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/CONTRIBUTING.md
@@ -0,0 +1,38 @@
+# Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+* (a) The contribution was created in whole or in part by me and I
+  have the right to submit it under the open source license
+  indicated in the file; or
+
+* (b) The contribution is based upon previous work that, to the best
+  of my knowledge, is covered under an appropriate open source
+  license and I have the right under that license to submit that
+  work with modifications, whether created in whole or in part
+  by me, under the same open source license (unless I am
+  permitted to submit under a different license), as indicated
+  in the file; or
+
+* (c) The contribution was provided directly to me by some other
+  person who certified (a), (b) or (c) and I have not modified
+  it.
+
+* (d) I understand and agree that this project and the contribution
+  are public and that a record of the contribution (including all
+  personal information I submit with it, including my sign-off) is
+  maintained indefinitely and may be redistributed consistent with
+  this project or the open source license(s) involved.
+
+## Moderation Policy
+
+The [Node.js Moderation Policy] applies to this WG.
+
+## Code of Conduct
+
+The [Node.js Code of Conduct][] applies to this WG.
+
+[Node.js Code of Conduct]:
+https://github.com/nodejs/node/blob/master/CODE_OF_CONDUCT.md
+[Node.js Moderation Policy]:
+https://github.com/nodejs/TSC/blob/master/Moderation-Policy.md
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/GOVERNANCE.md b/server/node_modules/are-we-there-yet/node_modules/readable-stream/GOVERNANCE.md
new file mode 100644
index 0000000..16ffb93
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/GOVERNANCE.md
@@ -0,0 +1,136 @@
+### Streams Working Group
+
+The Node.js Streams is jointly governed by a Working Group
+(WG)
+that is responsible for high-level guidance of the project.
+
+The WG has final authority over this project including:
+
+* Technical direction
+* Project governance and process (including this policy)
+* Contribution policy
+* GitHub repository hosting
+* Conduct guidelines
+* Maintaining the list of additional Collaborators
+
+For the current list of WG members, see the project
+[README.md](./README.md#current-project-team-members).
+
+### Collaborators
+
+The readable-stream GitHub repository is
+maintained by the WG and additional Collaborators who are added by the
+WG on an ongoing basis.
+
+Individuals making significant and valuable contributions are made
+Collaborators and given commit-access to the project. These
+individuals are identified by the WG and their addition as
+Collaborators is discussed during the WG meeting.
+
+_Note:_ If you make a significant contribution and are not considered
+for commit-access log an issue or contact a WG member directly and it
+will be brought up in the next WG meeting.
+
+Modifications of the contents of the readable-stream repository are
+made on
+a collaborative basis. Anybody with a GitHub account may propose a
+modification via pull request and it will be considered by the project
+Collaborators. All pull requests must be reviewed and accepted by a
+Collaborator with sufficient expertise who is able to take full
+responsibility for the change. In the case of pull requests proposed
+by an existing Collaborator, an additional Collaborator is required
+for sign-off. Consensus should be sought if additional Collaborators
+participate and there is disagreement around a particular
+modification. See _Consensus Seeking Process_ below for further detail
+on the consensus model used for governance.
+
+Collaborators may opt to elevate significant or controversial
+modifications, or modifications that have not found consensus to the
+WG for discussion by assigning the ***WG-agenda*** tag to a pull
+request or issue. The WG should serve as the final arbiter where
+required.
+
+For the current list of Collaborators, see the project
+[README.md](./README.md#members).
+
+### WG Membership
+
+WG seats are not time-limited.  There is no fixed size of the WG.
+However, the expected target is between 6 and 12, to ensure adequate
+coverage of important areas of expertise, balanced with the ability to
+make decisions efficiently.
+
+There is no specific set of requirements or qualifications for WG
+membership beyond these rules.
+
+The WG may add additional members to the WG by unanimous consensus.
+
+A WG member may be removed from the WG by voluntary resignation, or by
+unanimous consensus of all other WG members.
+
+Changes to WG membership should be posted in the agenda, and may be
+suggested as any other agenda item (see "WG Meetings" below).
+
+If an addition or removal is proposed during a meeting, and the full
+WG is not in attendance to participate, then the addition or removal
+is added to the agenda for the subsequent meeting.  This is to ensure
+that all members are given the opportunity to participate in all
+membership decisions.  If a WG member is unable to attend a meeting
+where a planned membership decision is being made, then their consent
+is assumed.
+
+No more than 1/3 of the WG members may be affiliated with the same
+employer.  If removal or resignation of a WG member, or a change of
+employment by a WG member, creates a situation where more than 1/3 of
+the WG membership shares an employer, then the situation must be
+immediately remedied by the resignation or removal of one or more WG
+members affiliated with the over-represented employer(s).
+
+### WG Meetings
+
+The WG meets occasionally on a Google Hangout On Air. A designated moderator
+approved by the WG runs the meeting. Each meeting should be
+published to YouTube.
+
+Items are added to the WG agenda that are considered contentious or
+are modifications of governance, contribution policy, WG membership,
+or release process.
+
+The intention of the agenda is not to approve or review all patches;
+that should happen continuously on GitHub and be handled by the larger
+group of Collaborators.
+
+Any community member or contributor can ask that something be added to
+the next meeting's agenda by logging a GitHub Issue. Any Collaborator,
+WG member or the moderator can add the item to the agenda by adding
+the ***WG-agenda*** tag to the issue.
+
+Prior to each WG meeting the moderator will share the Agenda with
+members of the WG. WG members can add any items they like to the
+agenda at the beginning of each meeting. The moderator and the WG
+cannot veto or remove items.
+
+The WG may invite persons or representatives from certain projects to
+participate in a non-voting capacity.
+
+The moderator is responsible for summarizing the discussion of each
+agenda item and sends it as a pull request after the meeting.
+
+### Consensus Seeking Process
+
+The WG follows a
+[Consensus
+Seeking](http://en.wikipedia.org/wiki/Consensus-seeking_decision-making)
+decision-making model.
+
+When an agenda item has appeared to reach a consensus the moderator
+will ask "Does anyone object?" as a final call for dissent from the
+consensus.
+
+If an agenda item cannot reach a consensus a WG member can call for
+either a closing vote or a vote to table the issue to the next
+meeting. The call for a vote must be seconded by a majority of the WG
+or else the discussion will continue. Simple majority wins.
+
+Note that changes to WG membership require a majority consensus.  See
+"WG Membership" above.
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/LICENSE b/server/node_modules/are-we-there-yet/node_modules/readable-stream/LICENSE
new file mode 100644
index 0000000..2873b3b
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/LICENSE
@@ -0,0 +1,47 @@
+Node.js is licensed for use as follows:
+
+"""
+Copyright Node.js contributors. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
+
+This license applies to parts of Node.js originating from the
+https://github.com/joyent/node repository:
+
+"""
+Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/README.md b/server/node_modules/are-we-there-yet/node_modules/readable-stream/README.md
new file mode 100644
index 0000000..19117c1
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/README.md
@@ -0,0 +1,106 @@
+# readable-stream
+
+***Node.js core streams for userland*** [![Build Status](https://travis-ci.com/nodejs/readable-stream.svg?branch=master)](https://travis-ci.com/nodejs/readable-stream)
+
+
+[![NPM](https://nodei.co/npm/readable-stream.png?downloads=true&downloadRank=true)](https://nodei.co/npm/readable-stream/)
+[![NPM](https://nodei.co/npm-dl/readable-stream.png?&months=6&height=3)](https://nodei.co/npm/readable-stream/)
+
+
+[![Sauce Test Status](https://saucelabs.com/browser-matrix/readabe-stream.svg)](https://saucelabs.com/u/readabe-stream)
+
+```bash
+npm install --save readable-stream
+```
+
+This package is a mirror of the streams implementations in Node.js.
+
+Full documentation may be found on the [Node.js website](https://nodejs.org/dist/v10.18.1/docs/api/stream.html).
+
+If you want to guarantee a stable streams base, regardless of what version of
+Node you, or the users of your libraries are using, use **readable-stream** *only* and avoid the *"stream"* module in Node-core, for background see [this blogpost](http://r.va.gg/2014/06/why-i-dont-use-nodes-core-stream-module.html).
+
+As of version 2.0.0 **readable-stream** uses semantic versioning.
+
+## Version 3.x.x
+
+v3.x.x of `readable-stream` is a cut from Node 10. This version supports Node 6, 8, and 10, as well as evergreen browsers, IE 11 and latest Safari. The breaking changes introduced by v3 are composed by the combined breaking changes in [Node v9](https://nodejs.org/en/blog/release/v9.0.0/) and [Node v10](https://nodejs.org/en/blog/release/v10.0.0/), as follows:
+
+1. Error codes: https://github.com/nodejs/node/pull/13310,
+   https://github.com/nodejs/node/pull/13291,
+   https://github.com/nodejs/node/pull/16589,
+   https://github.com/nodejs/node/pull/15042,
+   https://github.com/nodejs/node/pull/15665,
+   https://github.com/nodejs/readable-stream/pull/344
+2. 'readable' have precedence over flowing
+   https://github.com/nodejs/node/pull/18994
+3. make virtual methods errors consistent
+   https://github.com/nodejs/node/pull/18813
+4. updated streams error handling
+   https://github.com/nodejs/node/pull/18438
+5. writable.end should return this.
+   https://github.com/nodejs/node/pull/18780
+6. readable continues to read when push('')
+   https://github.com/nodejs/node/pull/18211
+7. add custom inspect to BufferList
+   https://github.com/nodejs/node/pull/17907
+8. always defer 'readable' with nextTick
+   https://github.com/nodejs/node/pull/17979
+
+## Version 2.x.x
+v2.x.x of `readable-stream` is a cut of the stream module from Node 8 (there have been no semver-major changes from Node 4 to 8). This version supports all Node.js versions from 0.8, as well as evergreen browsers and IE 10 & 11.
+
+### Big Thanks
+
+Cross-browser Testing Platform and Open Source <3 Provided by [Sauce Labs][sauce]
+
+# Usage
+
+You can swap your `require('stream')` with `require('readable-stream')`
+without any changes, if you are just using one of the main classes and
+functions.
+
+```js
+const {
+  Readable,
+  Writable,
+  Transform,
+  Duplex,
+  pipeline,
+  finished
+} = require('readable-stream')
+````
+
+Note that `require('stream')` will return `Stream`, while
+`require('readable-stream')` will return `Readable`. We discourage using
+whatever is exported directly, but rather use one of the properties as
+shown in the example above.
+
+# Streams Working Group
+
+`readable-stream` is maintained by the Streams Working Group, which
+oversees the development and maintenance of the Streams API within
+Node.js. The responsibilities of the Streams Working Group include:
+
+* Addressing stream issues on the Node.js issue tracker.
+* Authoring and editing stream documentation within the Node.js project.
+* Reviewing changes to stream subclasses within the Node.js project.
+* Redirecting changes to streams from the Node.js project to this
+  project.
+* Assisting in the implementation of stream providers within Node.js.
+* Recommending versions of `readable-stream` to be included in Node.js.
+* Messaging about the future of streams to give the community advance
+  notice of changes.
+
+<a name="members"></a>
+## Team Members
+
+* **Calvin Metcalf** ([@calvinmetcalf](https://github.com/calvinmetcalf)) <calvin.metcalf@gmail.com>
+  - Release GPG key: F3EF5F62A87FC27A22E643F714CE4FF5015AA242
+* **Mathias Buus** ([@mafintosh](https://github.com/mafintosh)) <mathiasbuus@gmail.com>
+* **Matteo Collina** ([@mcollina](https://github.com/mcollina)) <matteo.collina@gmail.com>
+  - Release GPG key: 3ABC01543F22DD2239285CDD818674489FBC127E
+* **Irina Shestak** ([@lrlna](https://github.com/lrlna)) <shestak.irina@gmail.com>
+* **Yoshua Wyuts** ([@yoshuawuyts](https://github.com/yoshuawuyts)) <yoshuawuyts@gmail.com>
+
+[sauce]: https://saucelabs.com
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/errors-browser.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/errors-browser.js
new file mode 100644
index 0000000..fb8e73e
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/errors-browser.js
@@ -0,0 +1,127 @@
+'use strict';
+
+function _inheritsLoose(subClass, superClass) { subClass.prototype = Object.create(superClass.prototype); subClass.prototype.constructor = subClass; subClass.__proto__ = superClass; }
+
+var codes = {};
+
+function createErrorType(code, message, Base) {
+  if (!Base) {
+    Base = Error;
+  }
+
+  function getMessage(arg1, arg2, arg3) {
+    if (typeof message === 'string') {
+      return message;
+    } else {
+      return message(arg1, arg2, arg3);
+    }
+  }
+
+  var NodeError =
+  /*#__PURE__*/
+  function (_Base) {
+    _inheritsLoose(NodeError, _Base);
+
+    function NodeError(arg1, arg2, arg3) {
+      return _Base.call(this, getMessage(arg1, arg2, arg3)) || this;
+    }
+
+    return NodeError;
+  }(Base);
+
+  NodeError.prototype.name = Base.name;
+  NodeError.prototype.code = code;
+  codes[code] = NodeError;
+} // https://github.com/nodejs/node/blob/v10.8.0/lib/internal/errors.js
+
+
+function oneOf(expected, thing) {
+  if (Array.isArray(expected)) {
+    var len = expected.length;
+    expected = expected.map(function (i) {
+      return String(i);
+    });
+
+    if (len > 2) {
+      return "one of ".concat(thing, " ").concat(expected.slice(0, len - 1).join(', '), ", or ") + expected[len - 1];
+    } else if (len === 2) {
+      return "one of ".concat(thing, " ").concat(expected[0], " or ").concat(expected[1]);
+    } else {
+      return "of ".concat(thing, " ").concat(expected[0]);
+    }
+  } else {
+    return "of ".concat(thing, " ").concat(String(expected));
+  }
+} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
+
+
+function startsWith(str, search, pos) {
+  return str.substr(!pos || pos < 0 ? 0 : +pos, search.length) === search;
+} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith
+
+
+function endsWith(str, search, this_len) {
+  if (this_len === undefined || this_len > str.length) {
+    this_len = str.length;
+  }
+
+  return str.substring(this_len - search.length, this_len) === search;
+} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes
+
+
+function includes(str, search, start) {
+  if (typeof start !== 'number') {
+    start = 0;
+  }
+
+  if (start + search.length > str.length) {
+    return false;
+  } else {
+    return str.indexOf(search, start) !== -1;
+  }
+}
+
+createErrorType('ERR_INVALID_OPT_VALUE', function (name, value) {
+  return 'The value "' + value + '" is invalid for option "' + name + '"';
+}, TypeError);
+createErrorType('ERR_INVALID_ARG_TYPE', function (name, expected, actual) {
+  // determiner: 'must be' or 'must not be'
+  var determiner;
+
+  if (typeof expected === 'string' && startsWith(expected, 'not ')) {
+    determiner = 'must not be';
+    expected = expected.replace(/^not /, '');
+  } else {
+    determiner = 'must be';
+  }
+
+  var msg;
+
+  if (endsWith(name, ' argument')) {
+    // For cases like 'first argument'
+    msg = "The ".concat(name, " ").concat(determiner, " ").concat(oneOf(expected, 'type'));
+  } else {
+    var type = includes(name, '.') ? 'property' : 'argument';
+    msg = "The \"".concat(name, "\" ").concat(type, " ").concat(determiner, " ").concat(oneOf(expected, 'type'));
+  }
+
+  msg += ". Received type ".concat(typeof actual);
+  return msg;
+}, TypeError);
+createErrorType('ERR_STREAM_PUSH_AFTER_EOF', 'stream.push() after EOF');
+createErrorType('ERR_METHOD_NOT_IMPLEMENTED', function (name) {
+  return 'The ' + name + ' method is not implemented';
+});
+createErrorType('ERR_STREAM_PREMATURE_CLOSE', 'Premature close');
+createErrorType('ERR_STREAM_DESTROYED', function (name) {
+  return 'Cannot call ' + name + ' after a stream was destroyed';
+});
+createErrorType('ERR_MULTIPLE_CALLBACK', 'Callback called multiple times');
+createErrorType('ERR_STREAM_CANNOT_PIPE', 'Cannot pipe, not readable');
+createErrorType('ERR_STREAM_WRITE_AFTER_END', 'write after end');
+createErrorType('ERR_STREAM_NULL_VALUES', 'May not write null values to stream', TypeError);
+createErrorType('ERR_UNKNOWN_ENCODING', function (arg) {
+  return 'Unknown encoding: ' + arg;
+}, TypeError);
+createErrorType('ERR_STREAM_UNSHIFT_AFTER_END_EVENT', 'stream.unshift() after end event');
+module.exports.codes = codes;
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/errors.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/errors.js
new file mode 100644
index 0000000..8471526
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/errors.js
@@ -0,0 +1,116 @@
+'use strict';
+
+const codes = {};
+
+function createErrorType(code, message, Base) {
+  if (!Base) {
+    Base = Error
+  }
+
+  function getMessage (arg1, arg2, arg3) {
+    if (typeof message === 'string') {
+      return message
+    } else {
+      return message(arg1, arg2, arg3)
+    }
+  }
+
+  class NodeError extends Base {
+    constructor (arg1, arg2, arg3) {
+      super(getMessage(arg1, arg2, arg3));
+    }
+  }
+
+  NodeError.prototype.name = Base.name;
+  NodeError.prototype.code = code;
+
+  codes[code] = NodeError;
+}
+
+// https://github.com/nodejs/node/blob/v10.8.0/lib/internal/errors.js
+function oneOf(expected, thing) {
+  if (Array.isArray(expected)) {
+    const len = expected.length;
+    expected = expected.map((i) => String(i));
+    if (len > 2) {
+      return `one of ${thing} ${expected.slice(0, len - 1).join(', ')}, or ` +
+             expected[len - 1];
+    } else if (len === 2) {
+      return `one of ${thing} ${expected[0]} or ${expected[1]}`;
+    } else {
+      return `of ${thing} ${expected[0]}`;
+    }
+  } else {
+    return `of ${thing} ${String(expected)}`;
+  }
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
+function startsWith(str, search, pos) {
+	return str.substr(!pos || pos < 0 ? 0 : +pos, search.length) === search;
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith
+function endsWith(str, search, this_len) {
+	if (this_len === undefined || this_len > str.length) {
+		this_len = str.length;
+	}
+	return str.substring(this_len - search.length, this_len) === search;
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes
+function includes(str, search, start) {
+  if (typeof start !== 'number') {
+    start = 0;
+  }
+
+  if (start + search.length > str.length) {
+    return false;
+  } else {
+    return str.indexOf(search, start) !== -1;
+  }
+}
+
+createErrorType('ERR_INVALID_OPT_VALUE', function (name, value) {
+  return 'The value "' + value + '" is invalid for option "' + name + '"'
+}, TypeError);
+createErrorType('ERR_INVALID_ARG_TYPE', function (name, expected, actual) {
+  // determiner: 'must be' or 'must not be'
+  let determiner;
+  if (typeof expected === 'string' && startsWith(expected, 'not ')) {
+    determiner = 'must not be';
+    expected = expected.replace(/^not /, '');
+  } else {
+    determiner = 'must be';
+  }
+
+  let msg;
+  if (endsWith(name, ' argument')) {
+    // For cases like 'first argument'
+    msg = `The ${name} ${determiner} ${oneOf(expected, 'type')}`;
+  } else {
+    const type = includes(name, '.') ? 'property' : 'argument';
+    msg = `The "${name}" ${type} ${determiner} ${oneOf(expected, 'type')}`;
+  }
+
+  msg += `. Received type ${typeof actual}`;
+  return msg;
+}, TypeError);
+createErrorType('ERR_STREAM_PUSH_AFTER_EOF', 'stream.push() after EOF');
+createErrorType('ERR_METHOD_NOT_IMPLEMENTED', function (name) {
+  return 'The ' + name + ' method is not implemented'
+});
+createErrorType('ERR_STREAM_PREMATURE_CLOSE', 'Premature close');
+createErrorType('ERR_STREAM_DESTROYED', function (name) {
+  return 'Cannot call ' + name + ' after a stream was destroyed';
+});
+createErrorType('ERR_MULTIPLE_CALLBACK', 'Callback called multiple times');
+createErrorType('ERR_STREAM_CANNOT_PIPE', 'Cannot pipe, not readable');
+createErrorType('ERR_STREAM_WRITE_AFTER_END', 'write after end');
+createErrorType('ERR_STREAM_NULL_VALUES', 'May not write null values to stream', TypeError);
+createErrorType('ERR_UNKNOWN_ENCODING', function (arg) {
+  return 'Unknown encoding: ' + arg
+}, TypeError);
+createErrorType('ERR_STREAM_UNSHIFT_AFTER_END_EVENT', 'stream.unshift() after end event');
+
+module.exports.codes = codes;
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/experimentalWarning.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/experimentalWarning.js
new file mode 100644
index 0000000..78e8414
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/experimentalWarning.js
@@ -0,0 +1,17 @@
+'use strict'
+
+var experimentalWarnings = new Set();
+
+function emitExperimentalWarning(feature) {
+  if (experimentalWarnings.has(feature)) return;
+  var msg = feature + ' is an experimental feature. This feature could ' +
+       'change at any time';
+  experimentalWarnings.add(feature);
+  process.emitWarning(msg, 'ExperimentalWarning');
+}
+
+function noop() {}
+
+module.exports.emitExperimentalWarning = process.emitWarning
+  ? emitExperimentalWarning
+  : noop;
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_duplex.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_duplex.js
new file mode 100644
index 0000000..19abfa6
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_duplex.js
@@ -0,0 +1,126 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a duplex stream is just a stream that is both readable and writable.
+// Since JS doesn't have multiple prototypal inheritance, this class
+// prototypally inherits from Readable, and then parasitically from
+// Writable.
+
+'use strict';
+
+/*<replacement>*/
+var objectKeys = Object.keys || function (obj) {
+  var keys = [];
+  for (var key in obj) keys.push(key);
+  return keys;
+};
+/*</replacement>*/
+
+module.exports = Duplex;
+var Readable = require('./_stream_readable');
+var Writable = require('./_stream_writable');
+require('inherits')(Duplex, Readable);
+{
+  // Allow the keys array to be GC'ed.
+  var keys = objectKeys(Writable.prototype);
+  for (var v = 0; v < keys.length; v++) {
+    var method = keys[v];
+    if (!Duplex.prototype[method]) Duplex.prototype[method] = Writable.prototype[method];
+  }
+}
+function Duplex(options) {
+  if (!(this instanceof Duplex)) return new Duplex(options);
+  Readable.call(this, options);
+  Writable.call(this, options);
+  this.allowHalfOpen = true;
+  if (options) {
+    if (options.readable === false) this.readable = false;
+    if (options.writable === false) this.writable = false;
+    if (options.allowHalfOpen === false) {
+      this.allowHalfOpen = false;
+      this.once('end', onend);
+    }
+  }
+}
+Object.defineProperty(Duplex.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.highWaterMark;
+  }
+});
+Object.defineProperty(Duplex.prototype, 'writableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState && this._writableState.getBuffer();
+  }
+});
+Object.defineProperty(Duplex.prototype, 'writableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.length;
+  }
+});
+
+// the no-half-open enforcer
+function onend() {
+  // If the writable side ended, then we're ok.
+  if (this._writableState.ended) return;
+
+  // no more data can be written.
+  // But allow more writes to happen in this tick.
+  process.nextTick(onEndNT, this);
+}
+function onEndNT(self) {
+  self.end();
+}
+Object.defineProperty(Duplex.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed && this._writableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+    this._writableState.destroyed = value;
+  }
+});
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_passthrough.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_passthrough.js
new file mode 100644
index 0000000..24a6bdd
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_passthrough.js
@@ -0,0 +1,37 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a passthrough stream.
+// basically just the most minimal sort of Transform stream.
+// Every written chunk gets output as-is.
+
+'use strict';
+
+module.exports = PassThrough;
+var Transform = require('./_stream_transform');
+require('inherits')(PassThrough, Transform);
+function PassThrough(options) {
+  if (!(this instanceof PassThrough)) return new PassThrough(options);
+  Transform.call(this, options);
+}
+PassThrough.prototype._transform = function (chunk, encoding, cb) {
+  cb(null, chunk);
+};
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_readable.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_readable.js
new file mode 100644
index 0000000..df1f608
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_readable.js
@@ -0,0 +1,1027 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+
+module.exports = Readable;
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Readable.ReadableState = ReadableState;
+
+/*<replacement>*/
+var EE = require('events').EventEmitter;
+var EElistenerCount = function EElistenerCount(emitter, type) {
+  return emitter.listeners(type).length;
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+var Buffer = require('buffer').Buffer;
+var OurUint8Array = (typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : typeof self !== 'undefined' ? self : {}).Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+
+/*<replacement>*/
+var debugUtil = require('util');
+var debug;
+if (debugUtil && debugUtil.debuglog) {
+  debug = debugUtil.debuglog('stream');
+} else {
+  debug = function debug() {};
+}
+/*</replacement>*/
+
+var BufferList = require('./internal/streams/buffer_list');
+var destroyImpl = require('./internal/streams/destroy');
+var _require = require('./internal/streams/state'),
+  getHighWaterMark = _require.getHighWaterMark;
+var _require$codes = require('../errors').codes,
+  ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
+  ERR_STREAM_PUSH_AFTER_EOF = _require$codes.ERR_STREAM_PUSH_AFTER_EOF,
+  ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_STREAM_UNSHIFT_AFTER_END_EVENT = _require$codes.ERR_STREAM_UNSHIFT_AFTER_END_EVENT;
+
+// Lazy loaded to improve the startup performance.
+var StringDecoder;
+var createReadableStreamAsyncIterator;
+var from;
+require('inherits')(Readable, Stream);
+var errorOrDestroy = destroyImpl.errorOrDestroy;
+var kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
+function prependListener(emitter, event, fn) {
+  // Sadly this is not cacheable as some libraries bundle their own
+  // event emitter implementation with them.
+  if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn);
+
+  // This is a hack to make sure that our error handler is attached before any
+  // userland ones.  NEVER DO THIS. This is here only because this code needs
+  // to continue to work with older versions of Node.js that do not include
+  // the prependListener() method. The goal is to eventually remove this hack.
+  if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (Array.isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
+}
+function ReadableState(options, stream, isDuplex) {
+  Duplex = Duplex || require('./_stream_duplex');
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream.
+  // These options can be provided separately as readableXXX and writableXXX.
+  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex;
+
+  // object stream flag. Used to make read(n) ignore n and to
+  // make all the buffer merging and length checks go away
+  this.objectMode = !!options.objectMode;
+  if (isDuplex) this.objectMode = this.objectMode || !!options.readableObjectMode;
+
+  // the point at which it stops calling _read() to fill the buffer
+  // Note: 0 is a valid value, means "don't call _read preemptively ever"
+  this.highWaterMark = getHighWaterMark(this, options, 'readableHighWaterMark', isDuplex);
+
+  // A linked list is used to store data chunks instead of an array because the
+  // linked list can remove elements from the beginning faster than
+  // array.shift()
+  this.buffer = new BufferList();
+  this.length = 0;
+  this.pipes = null;
+  this.pipesCount = 0;
+  this.flowing = null;
+  this.ended = false;
+  this.endEmitted = false;
+  this.reading = false;
+
+  // a flag to be able to tell if the event 'readable'/'data' is emitted
+  // immediately, or on a later tick.  We set this to true at first, because
+  // any actions that shouldn't happen until "later" should generally also
+  // not happen before the first read call.
+  this.sync = true;
+
+  // whenever we return null, then we set a flag to say
+  // that we're awaiting a 'readable' event emission.
+  this.needReadable = false;
+  this.emittedReadable = false;
+  this.readableListening = false;
+  this.resumeScheduled = false;
+  this.paused = true;
+
+  // Should close be emitted on destroy. Defaults to true.
+  this.emitClose = options.emitClose !== false;
+
+  // Should .destroy() be called after 'end' (and potentially 'finish')
+  this.autoDestroy = !!options.autoDestroy;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // the number of writers that are awaiting a drain event in .pipe()s
+  this.awaitDrain = 0;
+
+  // if true, a maybeReadMore has been scheduled
+  this.readingMore = false;
+  this.decoder = null;
+  this.encoding = null;
+  if (options.encoding) {
+    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+    this.decoder = new StringDecoder(options.encoding);
+    this.encoding = options.encoding;
+  }
+}
+function Readable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+  if (!(this instanceof Readable)) return new Readable(options);
+
+  // Checking for a Stream.Duplex instance is faster here instead of inside
+  // the ReadableState constructor, at least with V8 6.5
+  var isDuplex = this instanceof Duplex;
+  this._readableState = new ReadableState(options, this, isDuplex);
+
+  // legacy
+  this.readable = true;
+  if (options) {
+    if (typeof options.read === 'function') this._read = options.read;
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+  }
+  Stream.call(this);
+}
+Object.defineProperty(Readable.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._readableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._readableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+  }
+});
+Readable.prototype.destroy = destroyImpl.destroy;
+Readable.prototype._undestroy = destroyImpl.undestroy;
+Readable.prototype._destroy = function (err, cb) {
+  cb(err);
+};
+
+// Manually shove something into the read() buffer.
+// This returns true if the highWaterMark has not been hit yet,
+// similar to how Writable.write() returns true if you should
+// write() some more.
+Readable.prototype.push = function (chunk, encoding) {
+  var state = this._readableState;
+  var skipChunkCheck;
+  if (!state.objectMode) {
+    if (typeof chunk === 'string') {
+      encoding = encoding || state.defaultEncoding;
+      if (encoding !== state.encoding) {
+        chunk = Buffer.from(chunk, encoding);
+        encoding = '';
+      }
+      skipChunkCheck = true;
+    }
+  } else {
+    skipChunkCheck = true;
+  }
+  return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
+};
+
+// Unshift should *always* be something directly out of read()
+Readable.prototype.unshift = function (chunk) {
+  return readableAddChunk(this, chunk, null, true, false);
+};
+function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
+  debug('readableAddChunk', chunk);
+  var state = stream._readableState;
+  if (chunk === null) {
+    state.reading = false;
+    onEofChunk(stream, state);
+  } else {
+    var er;
+    if (!skipChunkCheck) er = chunkInvalid(state, chunk);
+    if (er) {
+      errorOrDestroy(stream, er);
+    } else if (state.objectMode || chunk && chunk.length > 0) {
+      if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
+        chunk = _uint8ArrayToBuffer(chunk);
+      }
+      if (addToFront) {
+        if (state.endEmitted) errorOrDestroy(stream, new ERR_STREAM_UNSHIFT_AFTER_END_EVENT());else addChunk(stream, state, chunk, true);
+      } else if (state.ended) {
+        errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
+      } else if (state.destroyed) {
+        return false;
+      } else {
+        state.reading = false;
+        if (state.decoder && !encoding) {
+          chunk = state.decoder.write(chunk);
+          if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
+        } else {
+          addChunk(stream, state, chunk, false);
+        }
+      }
+    } else if (!addToFront) {
+      state.reading = false;
+      maybeReadMore(stream, state);
+    }
+  }
+
+  // We can push more data if we are below the highWaterMark.
+  // Also, if we have no data yet, we can stand some more bytes.
+  // This is to work around cases where hwm=0, such as the repl.
+  return !state.ended && (state.length < state.highWaterMark || state.length === 0);
+}
+function addChunk(stream, state, chunk, addToFront) {
+  if (state.flowing && state.length === 0 && !state.sync) {
+    state.awaitDrain = 0;
+    stream.emit('data', chunk);
+  } else {
+    // update the buffer info.
+    state.length += state.objectMode ? 1 : chunk.length;
+    if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);
+    if (state.needReadable) emitReadable(stream);
+  }
+  maybeReadMore(stream, state);
+}
+function chunkInvalid(state, chunk) {
+  var er;
+  if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
+    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer', 'Uint8Array'], chunk);
+  }
+  return er;
+}
+Readable.prototype.isPaused = function () {
+  return this._readableState.flowing === false;
+};
+
+// backwards compatibility.
+Readable.prototype.setEncoding = function (enc) {
+  if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+  var decoder = new StringDecoder(enc);
+  this._readableState.decoder = decoder;
+  // If setEncoding(null), decoder.encoding equals utf8
+  this._readableState.encoding = this._readableState.decoder.encoding;
+
+  // Iterate over current buffer to convert already stored Buffers:
+  var p = this._readableState.buffer.head;
+  var content = '';
+  while (p !== null) {
+    content += decoder.write(p.data);
+    p = p.next;
+  }
+  this._readableState.buffer.clear();
+  if (content !== '') this._readableState.buffer.push(content);
+  this._readableState.length = content.length;
+  return this;
+};
+
+// Don't raise the hwm > 1GB
+var MAX_HWM = 0x40000000;
+function computeNewHighWaterMark(n) {
+  if (n >= MAX_HWM) {
+    // TODO(ronag): Throw ERR_VALUE_OUT_OF_RANGE.
+    n = MAX_HWM;
+  } else {
+    // Get the next highest power of 2 to prevent increasing hwm excessively in
+    // tiny amounts
+    n--;
+    n |= n >>> 1;
+    n |= n >>> 2;
+    n |= n >>> 4;
+    n |= n >>> 8;
+    n |= n >>> 16;
+    n++;
+  }
+  return n;
+}
+
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function howMuchToRead(n, state) {
+  if (n <= 0 || state.length === 0 && state.ended) return 0;
+  if (state.objectMode) return 1;
+  if (n !== n) {
+    // Only flow one buffer at a time
+    if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
+  }
+  // If we're asking for more than the current hwm, then raise the hwm.
+  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
+  if (n <= state.length) return n;
+  // Don't have enough
+  if (!state.ended) {
+    state.needReadable = true;
+    return 0;
+  }
+  return state.length;
+}
+
+// you can override either this method, or the async _read(n) below.
+Readable.prototype.read = function (n) {
+  debug('read', n);
+  n = parseInt(n, 10);
+  var state = this._readableState;
+  var nOrig = n;
+  if (n !== 0) state.emittedReadable = false;
+
+  // if we're doing read(0) to trigger a readable event, but we
+  // already have a bunch of data in the buffer, then just trigger
+  // the 'readable' event and move on.
+  if (n === 0 && state.needReadable && ((state.highWaterMark !== 0 ? state.length >= state.highWaterMark : state.length > 0) || state.ended)) {
+    debug('read: emitReadable', state.length, state.ended);
+    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
+    return null;
+  }
+  n = howMuchToRead(n, state);
+
+  // if we've ended, and we're now clear, then finish it up.
+  if (n === 0 && state.ended) {
+    if (state.length === 0) endReadable(this);
+    return null;
+  }
+
+  // All the actual chunk generation logic needs to be
+  // *below* the call to _read.  The reason is that in certain
+  // synthetic stream cases, such as passthrough streams, _read
+  // may be a completely synchronous operation which may change
+  // the state of the read buffer, providing enough data when
+  // before there was *not* enough.
+  //
+  // So, the steps are:
+  // 1. Figure out what the state of things will be after we do
+  // a read from the buffer.
+  //
+  // 2. If that resulting state will trigger a _read, then call _read.
+  // Note that this may be asynchronous, or synchronous.  Yes, it is
+  // deeply ugly to write APIs this way, but that still doesn't mean
+  // that the Readable class should behave improperly, as streams are
+  // designed to be sync/async agnostic.
+  // Take note if the _read call is sync or async (ie, if the read call
+  // has returned yet), so that we know whether or not it's safe to emit
+  // 'readable' etc.
+  //
+  // 3. Actually pull the requested chunks out of the buffer and return.
+
+  // if we need a readable event, then we need to do some reading.
+  var doRead = state.needReadable;
+  debug('need readable', doRead);
+
+  // if we currently have less than the highWaterMark, then also read some
+  if (state.length === 0 || state.length - n < state.highWaterMark) {
+    doRead = true;
+    debug('length less than watermark', doRead);
+  }
+
+  // however, if we've ended, then there's no point, and if we're already
+  // reading, then it's unnecessary.
+  if (state.ended || state.reading) {
+    doRead = false;
+    debug('reading or ended', doRead);
+  } else if (doRead) {
+    debug('do read');
+    state.reading = true;
+    state.sync = true;
+    // if the length is currently zero, then we *need* a readable event.
+    if (state.length === 0) state.needReadable = true;
+    // call internal read method
+    this._read(state.highWaterMark);
+    state.sync = false;
+    // If _read pushed data synchronously, then `reading` will be false,
+    // and we need to re-evaluate how much data we can return to the user.
+    if (!state.reading) n = howMuchToRead(nOrig, state);
+  }
+  var ret;
+  if (n > 0) ret = fromList(n, state);else ret = null;
+  if (ret === null) {
+    state.needReadable = state.length <= state.highWaterMark;
+    n = 0;
+  } else {
+    state.length -= n;
+    state.awaitDrain = 0;
+  }
+  if (state.length === 0) {
+    // If we have nothing in the buffer, then we want to know
+    // as soon as we *do* get something into the buffer.
+    if (!state.ended) state.needReadable = true;
+
+    // If we tried to read() past the EOF, then emit end on the next tick.
+    if (nOrig !== n && state.ended) endReadable(this);
+  }
+  if (ret !== null) this.emit('data', ret);
+  return ret;
+};
+function onEofChunk(stream, state) {
+  debug('onEofChunk');
+  if (state.ended) return;
+  if (state.decoder) {
+    var chunk = state.decoder.end();
+    if (chunk && chunk.length) {
+      state.buffer.push(chunk);
+      state.length += state.objectMode ? 1 : chunk.length;
+    }
+  }
+  state.ended = true;
+  if (state.sync) {
+    // if we are sync, wait until next tick to emit the data.
+    // Otherwise we risk emitting data in the flow()
+    // the readable code triggers during a read() call
+    emitReadable(stream);
+  } else {
+    // emit 'readable' now to make sure it gets picked up.
+    state.needReadable = false;
+    if (!state.emittedReadable) {
+      state.emittedReadable = true;
+      emitReadable_(stream);
+    }
+  }
+}
+
+// Don't emit readable right away in sync mode, because this can trigger
+// another read() call => stack overflow.  This way, it might trigger
+// a nextTick recursion warning, but that's not so bad.
+function emitReadable(stream) {
+  var state = stream._readableState;
+  debug('emitReadable', state.needReadable, state.emittedReadable);
+  state.needReadable = false;
+  if (!state.emittedReadable) {
+    debug('emitReadable', state.flowing);
+    state.emittedReadable = true;
+    process.nextTick(emitReadable_, stream);
+  }
+}
+function emitReadable_(stream) {
+  var state = stream._readableState;
+  debug('emitReadable_', state.destroyed, state.length, state.ended);
+  if (!state.destroyed && (state.length || state.ended)) {
+    stream.emit('readable');
+    state.emittedReadable = false;
+  }
+
+  // The stream needs another readable event if
+  // 1. It is not flowing, as the flow mechanism will take
+  //    care of it.
+  // 2. It is not ended.
+  // 3. It is below the highWaterMark, so we can schedule
+  //    another readable later.
+  state.needReadable = !state.flowing && !state.ended && state.length <= state.highWaterMark;
+  flow(stream);
+}
+
+// at this point, the user has presumably seen the 'readable' event,
+// and called read() to consume some data.  that may have triggered
+// in turn another _read(n) call, in which case reading = true if
+// it's in progress.
+// However, if we're not ended, or reading, and the length < hwm,
+// then go ahead and try to read some more preemptively.
+function maybeReadMore(stream, state) {
+  if (!state.readingMore) {
+    state.readingMore = true;
+    process.nextTick(maybeReadMore_, stream, state);
+  }
+}
+function maybeReadMore_(stream, state) {
+  // Attempt to read more data if we should.
+  //
+  // The conditions for reading more data are (one of):
+  // - Not enough data buffered (state.length < state.highWaterMark). The loop
+  //   is responsible for filling the buffer with enough data if such data
+  //   is available. If highWaterMark is 0 and we are not in the flowing mode
+  //   we should _not_ attempt to buffer any extra data. We'll get more data
+  //   when the stream consumer calls read() instead.
+  // - No data in the buffer, and the stream is in flowing mode. In this mode
+  //   the loop below is responsible for ensuring read() is called. Failing to
+  //   call read here would abort the flow and there's no other mechanism for
+  //   continuing the flow if the stream consumer has just subscribed to the
+  //   'data' event.
+  //
+  // In addition to the above conditions to keep reading data, the following
+  // conditions prevent the data from being read:
+  // - The stream has ended (state.ended).
+  // - There is already a pending 'read' operation (state.reading). This is a
+  //   case where the the stream has called the implementation defined _read()
+  //   method, but they are processing the call asynchronously and have _not_
+  //   called push() with new data. In this case we skip performing more
+  //   read()s. The execution ends in this method again after the _read() ends
+  //   up calling push() with more data.
+  while (!state.reading && !state.ended && (state.length < state.highWaterMark || state.flowing && state.length === 0)) {
+    var len = state.length;
+    debug('maybeReadMore read 0');
+    stream.read(0);
+    if (len === state.length)
+      // didn't get any data, stop spinning.
+      break;
+  }
+  state.readingMore = false;
+}
+
+// abstract method.  to be overridden in specific implementation classes.
+// call cb(er, data) where data is <= n in length.
+// for virtual (non-string, non-buffer) streams, "length" is somewhat
+// arbitrary, and perhaps not very meaningful.
+Readable.prototype._read = function (n) {
+  errorOrDestroy(this, new ERR_METHOD_NOT_IMPLEMENTED('_read()'));
+};
+Readable.prototype.pipe = function (dest, pipeOpts) {
+  var src = this;
+  var state = this._readableState;
+  switch (state.pipesCount) {
+    case 0:
+      state.pipes = dest;
+      break;
+    case 1:
+      state.pipes = [state.pipes, dest];
+      break;
+    default:
+      state.pipes.push(dest);
+      break;
+  }
+  state.pipesCount += 1;
+  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
+  var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;
+  var endFn = doEnd ? onend : unpipe;
+  if (state.endEmitted) process.nextTick(endFn);else src.once('end', endFn);
+  dest.on('unpipe', onunpipe);
+  function onunpipe(readable, unpipeInfo) {
+    debug('onunpipe');
+    if (readable === src) {
+      if (unpipeInfo && unpipeInfo.hasUnpiped === false) {
+        unpipeInfo.hasUnpiped = true;
+        cleanup();
+      }
+    }
+  }
+  function onend() {
+    debug('onend');
+    dest.end();
+  }
+
+  // when the dest drains, it reduces the awaitDrain counter
+  // on the source.  This would be more elegant with a .once()
+  // handler in flow(), but adding and removing repeatedly is
+  // too slow.
+  var ondrain = pipeOnDrain(src);
+  dest.on('drain', ondrain);
+  var cleanedUp = false;
+  function cleanup() {
+    debug('cleanup');
+    // cleanup event handlers once the pipe is broken
+    dest.removeListener('close', onclose);
+    dest.removeListener('finish', onfinish);
+    dest.removeListener('drain', ondrain);
+    dest.removeListener('error', onerror);
+    dest.removeListener('unpipe', onunpipe);
+    src.removeListener('end', onend);
+    src.removeListener('end', unpipe);
+    src.removeListener('data', ondata);
+    cleanedUp = true;
+
+    // if the reader is waiting for a drain event from this
+    // specific writer, then it would cause it to never start
+    // flowing again.
+    // So, if this is awaiting a drain, then we just call it now.
+    // If we don't know, then assume that we are waiting for one.
+    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
+  }
+  src.on('data', ondata);
+  function ondata(chunk) {
+    debug('ondata');
+    var ret = dest.write(chunk);
+    debug('dest.write', ret);
+    if (ret === false) {
+      // If the user unpiped during `dest.write()`, it is possible
+      // to get stuck in a permanently paused state if that write
+      // also returned false.
+      // => Check whether `dest` is still a piping destination.
+      if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
+        debug('false write response, pause', state.awaitDrain);
+        state.awaitDrain++;
+      }
+      src.pause();
+    }
+  }
+
+  // if the dest has an error, then stop piping into it.
+  // however, don't suppress the throwing behavior for this.
+  function onerror(er) {
+    debug('onerror', er);
+    unpipe();
+    dest.removeListener('error', onerror);
+    if (EElistenerCount(dest, 'error') === 0) errorOrDestroy(dest, er);
+  }
+
+  // Make sure our error handler is attached before userland ones.
+  prependListener(dest, 'error', onerror);
+
+  // Both close and finish should trigger unpipe, but only once.
+  function onclose() {
+    dest.removeListener('finish', onfinish);
+    unpipe();
+  }
+  dest.once('close', onclose);
+  function onfinish() {
+    debug('onfinish');
+    dest.removeListener('close', onclose);
+    unpipe();
+  }
+  dest.once('finish', onfinish);
+  function unpipe() {
+    debug('unpipe');
+    src.unpipe(dest);
+  }
+
+  // tell the dest that it's being piped to
+  dest.emit('pipe', src);
+
+  // start the flow if it hasn't been started already.
+  if (!state.flowing) {
+    debug('pipe resume');
+    src.resume();
+  }
+  return dest;
+};
+function pipeOnDrain(src) {
+  return function pipeOnDrainFunctionResult() {
+    var state = src._readableState;
+    debug('pipeOnDrain', state.awaitDrain);
+    if (state.awaitDrain) state.awaitDrain--;
+    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
+      state.flowing = true;
+      flow(src);
+    }
+  };
+}
+Readable.prototype.unpipe = function (dest) {
+  var state = this._readableState;
+  var unpipeInfo = {
+    hasUnpiped: false
+  };
+
+  // if we're not piping anywhere, then do nothing.
+  if (state.pipesCount === 0) return this;
+
+  // just one destination.  most common case.
+  if (state.pipesCount === 1) {
+    // passed in one, but it's not the right one.
+    if (dest && dest !== state.pipes) return this;
+    if (!dest) dest = state.pipes;
+
+    // got a match.
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    if (dest) dest.emit('unpipe', this, unpipeInfo);
+    return this;
+  }
+
+  // slow case. multiple pipe destinations.
+
+  if (!dest) {
+    // remove all.
+    var dests = state.pipes;
+    var len = state.pipesCount;
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    for (var i = 0; i < len; i++) dests[i].emit('unpipe', this, {
+      hasUnpiped: false
+    });
+    return this;
+  }
+
+  // try to find the right one.
+  var index = indexOf(state.pipes, dest);
+  if (index === -1) return this;
+  state.pipes.splice(index, 1);
+  state.pipesCount -= 1;
+  if (state.pipesCount === 1) state.pipes = state.pipes[0];
+  dest.emit('unpipe', this, unpipeInfo);
+  return this;
+};
+
+// set up data events if they are asked for
+// Ensure readable listeners eventually get something
+Readable.prototype.on = function (ev, fn) {
+  var res = Stream.prototype.on.call(this, ev, fn);
+  var state = this._readableState;
+  if (ev === 'data') {
+    // update readableListening so that resume() may be a no-op
+    // a few lines down. This is needed to support once('readable').
+    state.readableListening = this.listenerCount('readable') > 0;
+
+    // Try start flowing on next tick if stream isn't explicitly paused
+    if (state.flowing !== false) this.resume();
+  } else if (ev === 'readable') {
+    if (!state.endEmitted && !state.readableListening) {
+      state.readableListening = state.needReadable = true;
+      state.flowing = false;
+      state.emittedReadable = false;
+      debug('on readable', state.length, state.reading);
+      if (state.length) {
+        emitReadable(this);
+      } else if (!state.reading) {
+        process.nextTick(nReadingNextTick, this);
+      }
+    }
+  }
+  return res;
+};
+Readable.prototype.addListener = Readable.prototype.on;
+Readable.prototype.removeListener = function (ev, fn) {
+  var res = Stream.prototype.removeListener.call(this, ev, fn);
+  if (ev === 'readable') {
+    // We need to check if there is someone still listening to
+    // readable and reset the state. However this needs to happen
+    // after readable has been emitted but before I/O (nextTick) to
+    // support once('readable', fn) cycles. This means that calling
+    // resume within the same tick will have no
+    // effect.
+    process.nextTick(updateReadableListening, this);
+  }
+  return res;
+};
+Readable.prototype.removeAllListeners = function (ev) {
+  var res = Stream.prototype.removeAllListeners.apply(this, arguments);
+  if (ev === 'readable' || ev === undefined) {
+    // We need to check if there is someone still listening to
+    // readable and reset the state. However this needs to happen
+    // after readable has been emitted but before I/O (nextTick) to
+    // support once('readable', fn) cycles. This means that calling
+    // resume within the same tick will have no
+    // effect.
+    process.nextTick(updateReadableListening, this);
+  }
+  return res;
+};
+function updateReadableListening(self) {
+  var state = self._readableState;
+  state.readableListening = self.listenerCount('readable') > 0;
+  if (state.resumeScheduled && !state.paused) {
+    // flowing needs to be set to true now, otherwise
+    // the upcoming resume will not flow.
+    state.flowing = true;
+
+    // crude way to check if we should resume
+  } else if (self.listenerCount('data') > 0) {
+    self.resume();
+  }
+}
+function nReadingNextTick(self) {
+  debug('readable nexttick read 0');
+  self.read(0);
+}
+
+// pause() and resume() are remnants of the legacy readable stream API
+// If the user uses them, then switch into old mode.
+Readable.prototype.resume = function () {
+  var state = this._readableState;
+  if (!state.flowing) {
+    debug('resume');
+    // we flow only if there is no one listening
+    // for readable, but we still have to call
+    // resume()
+    state.flowing = !state.readableListening;
+    resume(this, state);
+  }
+  state.paused = false;
+  return this;
+};
+function resume(stream, state) {
+  if (!state.resumeScheduled) {
+    state.resumeScheduled = true;
+    process.nextTick(resume_, stream, state);
+  }
+}
+function resume_(stream, state) {
+  debug('resume', state.reading);
+  if (!state.reading) {
+    stream.read(0);
+  }
+  state.resumeScheduled = false;
+  stream.emit('resume');
+  flow(stream);
+  if (state.flowing && !state.reading) stream.read(0);
+}
+Readable.prototype.pause = function () {
+  debug('call pause flowing=%j', this._readableState.flowing);
+  if (this._readableState.flowing !== false) {
+    debug('pause');
+    this._readableState.flowing = false;
+    this.emit('pause');
+  }
+  this._readableState.paused = true;
+  return this;
+};
+function flow(stream) {
+  var state = stream._readableState;
+  debug('flow', state.flowing);
+  while (state.flowing && stream.read() !== null);
+}
+
+// wrap an old-style stream as the async data source.
+// This is *not* part of the readable stream interface.
+// It is an ugly unfortunate mess of history.
+Readable.prototype.wrap = function (stream) {
+  var _this = this;
+  var state = this._readableState;
+  var paused = false;
+  stream.on('end', function () {
+    debug('wrapped end');
+    if (state.decoder && !state.ended) {
+      var chunk = state.decoder.end();
+      if (chunk && chunk.length) _this.push(chunk);
+    }
+    _this.push(null);
+  });
+  stream.on('data', function (chunk) {
+    debug('wrapped data');
+    if (state.decoder) chunk = state.decoder.write(chunk);
+
+    // don't skip over falsy values in objectMode
+    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;
+    var ret = _this.push(chunk);
+    if (!ret) {
+      paused = true;
+      stream.pause();
+    }
+  });
+
+  // proxy all the other methods.
+  // important when wrapping filters and duplexes.
+  for (var i in stream) {
+    if (this[i] === undefined && typeof stream[i] === 'function') {
+      this[i] = function methodWrap(method) {
+        return function methodWrapReturnFunction() {
+          return stream[method].apply(stream, arguments);
+        };
+      }(i);
+    }
+  }
+
+  // proxy certain important events.
+  for (var n = 0; n < kProxyEvents.length; n++) {
+    stream.on(kProxyEvents[n], this.emit.bind(this, kProxyEvents[n]));
+  }
+
+  // when we try to consume some more bytes, simply unpause the
+  // underlying stream.
+  this._read = function (n) {
+    debug('wrapped _read', n);
+    if (paused) {
+      paused = false;
+      stream.resume();
+    }
+  };
+  return this;
+};
+if (typeof Symbol === 'function') {
+  Readable.prototype[Symbol.asyncIterator] = function () {
+    if (createReadableStreamAsyncIterator === undefined) {
+      createReadableStreamAsyncIterator = require('./internal/streams/async_iterator');
+    }
+    return createReadableStreamAsyncIterator(this);
+  };
+}
+Object.defineProperty(Readable.prototype, 'readableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.highWaterMark;
+  }
+});
+Object.defineProperty(Readable.prototype, 'readableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState && this._readableState.buffer;
+  }
+});
+Object.defineProperty(Readable.prototype, 'readableFlowing', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.flowing;
+  },
+  set: function set(state) {
+    if (this._readableState) {
+      this._readableState.flowing = state;
+    }
+  }
+});
+
+// exposed for testing purposes only.
+Readable._fromList = fromList;
+Object.defineProperty(Readable.prototype, 'readableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.length;
+  }
+});
+
+// Pluck off n bytes from an array of buffers.
+// Length is the combined lengths of all the buffers in the list.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function fromList(n, state) {
+  // nothing buffered
+  if (state.length === 0) return null;
+  var ret;
+  if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
+    // read it all, truncate the list
+    if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.first();else ret = state.buffer.concat(state.length);
+    state.buffer.clear();
+  } else {
+    // read part of list
+    ret = state.buffer.consume(n, state.decoder);
+  }
+  return ret;
+}
+function endReadable(stream) {
+  var state = stream._readableState;
+  debug('endReadable', state.endEmitted);
+  if (!state.endEmitted) {
+    state.ended = true;
+    process.nextTick(endReadableNT, state, stream);
+  }
+}
+function endReadableNT(state, stream) {
+  debug('endReadableNT', state.endEmitted, state.length);
+
+  // Check that we didn't get one last unshift.
+  if (!state.endEmitted && state.length === 0) {
+    state.endEmitted = true;
+    stream.readable = false;
+    stream.emit('end');
+    if (state.autoDestroy) {
+      // In case of duplex streams we need a way to detect
+      // if the writable side is ready for autoDestroy as well
+      var wState = stream._writableState;
+      if (!wState || wState.autoDestroy && wState.finished) {
+        stream.destroy();
+      }
+    }
+  }
+}
+if (typeof Symbol === 'function') {
+  Readable.from = function (iterable, opts) {
+    if (from === undefined) {
+      from = require('./internal/streams/from');
+    }
+    return from(Readable, iterable, opts);
+  };
+}
+function indexOf(xs, x) {
+  for (var i = 0, l = xs.length; i < l; i++) {
+    if (xs[i] === x) return i;
+  }
+  return -1;
+}
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_transform.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_transform.js
new file mode 100644
index 0000000..1ccb715
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_transform.js
@@ -0,0 +1,190 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a transform stream is a readable/writable stream where you do
+// something with the data.  Sometimes it's called a "filter",
+// but that's not a great name for it, since that implies a thing where
+// some bits pass through, and others are simply ignored.  (That would
+// be a valid example of a transform, of course.)
+//
+// While the output is causally related to the input, it's not a
+// necessarily symmetric or synchronous transformation.  For example,
+// a zlib stream might take multiple plain-text writes(), and then
+// emit a single compressed chunk some time in the future.
+//
+// Here's how this works:
+//
+// The Transform stream has all the aspects of the readable and writable
+// stream classes.  When you write(chunk), that calls _write(chunk,cb)
+// internally, and returns false if there's a lot of pending writes
+// buffered up.  When you call read(), that calls _read(n) until
+// there's enough pending readable data buffered up.
+//
+// In a transform stream, the written data is placed in a buffer.  When
+// _read(n) is called, it transforms the queued up data, calling the
+// buffered _write cb's as it consumes chunks.  If consuming a single
+// written chunk would result in multiple output chunks, then the first
+// outputted bit calls the readcb, and subsequent chunks just go into
+// the read buffer, and will cause it to emit 'readable' if necessary.
+//
+// This way, back-pressure is actually determined by the reading side,
+// since _read has to be called to start processing a new chunk.  However,
+// a pathological inflate type of transform can cause excessive buffering
+// here.  For example, imagine a stream where every byte of input is
+// interpreted as an integer from 0-255, and then results in that many
+// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
+// 1kb of data being output.  In this case, you could write a very small
+// amount of input, and end up with a very large amount of output.  In
+// such a pathological inflating mechanism, there'd be no way to tell
+// the system to stop doing the transform.  A single 4MB write could
+// cause the system to run out of memory.
+//
+// However, even in such a pathological case, only a single written chunk
+// would be consumed, and then the rest would wait (un-transformed) until
+// the results of the previous transformed chunk were consumed.
+
+'use strict';
+
+module.exports = Transform;
+var _require$codes = require('../errors').codes,
+  ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
+  ERR_TRANSFORM_ALREADY_TRANSFORMING = _require$codes.ERR_TRANSFORM_ALREADY_TRANSFORMING,
+  ERR_TRANSFORM_WITH_LENGTH_0 = _require$codes.ERR_TRANSFORM_WITH_LENGTH_0;
+var Duplex = require('./_stream_duplex');
+require('inherits')(Transform, Duplex);
+function afterTransform(er, data) {
+  var ts = this._transformState;
+  ts.transforming = false;
+  var cb = ts.writecb;
+  if (cb === null) {
+    return this.emit('error', new ERR_MULTIPLE_CALLBACK());
+  }
+  ts.writechunk = null;
+  ts.writecb = null;
+  if (data != null)
+    // single equals check for both `null` and `undefined`
+    this.push(data);
+  cb(er);
+  var rs = this._readableState;
+  rs.reading = false;
+  if (rs.needReadable || rs.length < rs.highWaterMark) {
+    this._read(rs.highWaterMark);
+  }
+}
+function Transform(options) {
+  if (!(this instanceof Transform)) return new Transform(options);
+  Duplex.call(this, options);
+  this._transformState = {
+    afterTransform: afterTransform.bind(this),
+    needTransform: false,
+    transforming: false,
+    writecb: null,
+    writechunk: null,
+    writeencoding: null
+  };
+
+  // start out asking for a readable event once data is transformed.
+  this._readableState.needReadable = true;
+
+  // we have implemented the _read method, and done the other things
+  // that Readable wants before the first _read call, so unset the
+  // sync guard flag.
+  this._readableState.sync = false;
+  if (options) {
+    if (typeof options.transform === 'function') this._transform = options.transform;
+    if (typeof options.flush === 'function') this._flush = options.flush;
+  }
+
+  // When the writable side finishes, then flush out anything remaining.
+  this.on('prefinish', prefinish);
+}
+function prefinish() {
+  var _this = this;
+  if (typeof this._flush === 'function' && !this._readableState.destroyed) {
+    this._flush(function (er, data) {
+      done(_this, er, data);
+    });
+  } else {
+    done(this, null, null);
+  }
+}
+Transform.prototype.push = function (chunk, encoding) {
+  this._transformState.needTransform = false;
+  return Duplex.prototype.push.call(this, chunk, encoding);
+};
+
+// This is the part where you do stuff!
+// override this function in implementation classes.
+// 'chunk' is an input chunk.
+//
+// Call `push(newChunk)` to pass along transformed output
+// to the readable side.  You may call 'push' zero or more times.
+//
+// Call `cb(err)` when you are done with this chunk.  If you pass
+// an error, then that'll put the hurt on the whole operation.  If you
+// never call cb(), then you'll never get another chunk.
+Transform.prototype._transform = function (chunk, encoding, cb) {
+  cb(new ERR_METHOD_NOT_IMPLEMENTED('_transform()'));
+};
+Transform.prototype._write = function (chunk, encoding, cb) {
+  var ts = this._transformState;
+  ts.writecb = cb;
+  ts.writechunk = chunk;
+  ts.writeencoding = encoding;
+  if (!ts.transforming) {
+    var rs = this._readableState;
+    if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
+  }
+};
+
+// Doesn't matter what the args are here.
+// _transform does all the work.
+// That we got here means that the readable side wants more data.
+Transform.prototype._read = function (n) {
+  var ts = this._transformState;
+  if (ts.writechunk !== null && !ts.transforming) {
+    ts.transforming = true;
+    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
+  } else {
+    // mark that we need a transform, so that any data that comes in
+    // will get processed, now that we've asked for it.
+    ts.needTransform = true;
+  }
+};
+Transform.prototype._destroy = function (err, cb) {
+  Duplex.prototype._destroy.call(this, err, function (err2) {
+    cb(err2);
+  });
+};
+function done(stream, er, data) {
+  if (er) return stream.emit('error', er);
+  if (data != null)
+    // single equals check for both `null` and `undefined`
+    stream.push(data);
+
+  // TODO(BridgeAR): Write a test for these two error cases
+  // if there's nothing in the write buffer, then that means
+  // that nothing more will ever be provided
+  if (stream._writableState.length) throw new ERR_TRANSFORM_WITH_LENGTH_0();
+  if (stream._transformState.transforming) throw new ERR_TRANSFORM_ALREADY_TRANSFORMING();
+  return stream.push(null);
+}
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_writable.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_writable.js
new file mode 100644
index 0000000..292415e
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/_stream_writable.js
@@ -0,0 +1,641 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// A bit simpler than readable streams.
+// Implement an async ._write(chunk, encoding, cb), and it'll handle all
+// the drain event emission and buffering.
+
+'use strict';
+
+module.exports = Writable;
+
+/* <replacement> */
+function WriteReq(chunk, encoding, cb) {
+  this.chunk = chunk;
+  this.encoding = encoding;
+  this.callback = cb;
+  this.next = null;
+}
+
+// It seems a linked list but it is not
+// there will be only 2 of these for each stream
+function CorkedRequest(state) {
+  var _this = this;
+  this.next = null;
+  this.entry = null;
+  this.finish = function () {
+    onCorkedFinish(_this, state);
+  };
+}
+/* </replacement> */
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Writable.WritableState = WritableState;
+
+/*<replacement>*/
+var internalUtil = {
+  deprecate: require('util-deprecate')
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+var Buffer = require('buffer').Buffer;
+var OurUint8Array = (typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : typeof self !== 'undefined' ? self : {}).Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+var destroyImpl = require('./internal/streams/destroy');
+var _require = require('./internal/streams/state'),
+  getHighWaterMark = _require.getHighWaterMark;
+var _require$codes = require('../errors').codes,
+  ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
+  ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
+  ERR_STREAM_CANNOT_PIPE = _require$codes.ERR_STREAM_CANNOT_PIPE,
+  ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED,
+  ERR_STREAM_NULL_VALUES = _require$codes.ERR_STREAM_NULL_VALUES,
+  ERR_STREAM_WRITE_AFTER_END = _require$codes.ERR_STREAM_WRITE_AFTER_END,
+  ERR_UNKNOWN_ENCODING = _require$codes.ERR_UNKNOWN_ENCODING;
+var errorOrDestroy = destroyImpl.errorOrDestroy;
+require('inherits')(Writable, Stream);
+function nop() {}
+function WritableState(options, stream, isDuplex) {
+  Duplex = Duplex || require('./_stream_duplex');
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream,
+  // e.g. options.readableObjectMode vs. options.writableObjectMode, etc.
+  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex;
+
+  // object stream flag to indicate whether or not this stream
+  // contains buffers or objects.
+  this.objectMode = !!options.objectMode;
+  if (isDuplex) this.objectMode = this.objectMode || !!options.writableObjectMode;
+
+  // the point at which write() starts returning false
+  // Note: 0 is a valid value, means that we always return false if
+  // the entire buffer is not flushed immediately on write()
+  this.highWaterMark = getHighWaterMark(this, options, 'writableHighWaterMark', isDuplex);
+
+  // if _final has been called
+  this.finalCalled = false;
+
+  // drain event flag.
+  this.needDrain = false;
+  // at the start of calling end()
+  this.ending = false;
+  // when end() has been called, and returned
+  this.ended = false;
+  // when 'finish' is emitted
+  this.finished = false;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // should we decode strings into buffers before passing to _write?
+  // this is here so that some node-core streams can optimize string
+  // handling at a lower level.
+  var noDecode = options.decodeStrings === false;
+  this.decodeStrings = !noDecode;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // not an actual buffer we keep track of, but a measurement
+  // of how much we're waiting to get pushed to some underlying
+  // socket or file.
+  this.length = 0;
+
+  // a flag to see when we're in the middle of a write.
+  this.writing = false;
+
+  // when true all writes will be buffered until .uncork() call
+  this.corked = 0;
+
+  // a flag to be able to tell if the onwrite cb is called immediately,
+  // or on a later tick.  We set this to true at first, because any
+  // actions that shouldn't happen until "later" should generally also
+  // not happen before the first write call.
+  this.sync = true;
+
+  // a flag to know if we're processing previously buffered items, which
+  // may call the _write() callback in the same tick, so that we don't
+  // end up in an overlapped onwrite situation.
+  this.bufferProcessing = false;
+
+  // the callback that's passed to _write(chunk,cb)
+  this.onwrite = function (er) {
+    onwrite(stream, er);
+  };
+
+  // the callback that the user supplies to write(chunk,encoding,cb)
+  this.writecb = null;
+
+  // the amount that is being written when _write is called.
+  this.writelen = 0;
+  this.bufferedRequest = null;
+  this.lastBufferedRequest = null;
+
+  // number of pending user-supplied write callbacks
+  // this must be 0 before 'finish' can be emitted
+  this.pendingcb = 0;
+
+  // emit prefinish if the only thing we're waiting for is _write cbs
+  // This is relevant for synchronous Transform streams
+  this.prefinished = false;
+
+  // True if the error was already emitted and should not be thrown again
+  this.errorEmitted = false;
+
+  // Should close be emitted on destroy. Defaults to true.
+  this.emitClose = options.emitClose !== false;
+
+  // Should .destroy() be called after 'finish' (and potentially 'end')
+  this.autoDestroy = !!options.autoDestroy;
+
+  // count buffered requests
+  this.bufferedRequestCount = 0;
+
+  // allocate the first CorkedRequest, there is always
+  // one allocated and free to use, and we maintain at most two
+  this.corkedRequestsFree = new CorkedRequest(this);
+}
+WritableState.prototype.getBuffer = function getBuffer() {
+  var current = this.bufferedRequest;
+  var out = [];
+  while (current) {
+    out.push(current);
+    current = current.next;
+  }
+  return out;
+};
+(function () {
+  try {
+    Object.defineProperty(WritableState.prototype, 'buffer', {
+      get: internalUtil.deprecate(function writableStateBufferGetter() {
+        return this.getBuffer();
+      }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.', 'DEP0003')
+    });
+  } catch (_) {}
+})();
+
+// Test _writableState for inheritance to account for Duplex streams,
+// whose prototype chain only points to Readable.
+var realHasInstance;
+if (typeof Symbol === 'function' && Symbol.hasInstance && typeof Function.prototype[Symbol.hasInstance] === 'function') {
+  realHasInstance = Function.prototype[Symbol.hasInstance];
+  Object.defineProperty(Writable, Symbol.hasInstance, {
+    value: function value(object) {
+      if (realHasInstance.call(this, object)) return true;
+      if (this !== Writable) return false;
+      return object && object._writableState instanceof WritableState;
+    }
+  });
+} else {
+  realHasInstance = function realHasInstance(object) {
+    return object instanceof this;
+  };
+}
+function Writable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  // Writable ctor is applied to Duplexes, too.
+  // `realHasInstance` is necessary because using plain `instanceof`
+  // would return false, as no `_writableState` property is attached.
+
+  // Trying to use the custom `instanceof` for Writable here will also break the
+  // Node.js LazyTransform implementation, which has a non-trivial getter for
+  // `_writableState` that would lead to infinite recursion.
+
+  // Checking for a Stream.Duplex instance is faster here instead of inside
+  // the WritableState constructor, at least with V8 6.5
+  var isDuplex = this instanceof Duplex;
+  if (!isDuplex && !realHasInstance.call(Writable, this)) return new Writable(options);
+  this._writableState = new WritableState(options, this, isDuplex);
+
+  // legacy.
+  this.writable = true;
+  if (options) {
+    if (typeof options.write === 'function') this._write = options.write;
+    if (typeof options.writev === 'function') this._writev = options.writev;
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+    if (typeof options.final === 'function') this._final = options.final;
+  }
+  Stream.call(this);
+}
+
+// Otherwise people can pipe Writable streams, which is just wrong.
+Writable.prototype.pipe = function () {
+  errorOrDestroy(this, new ERR_STREAM_CANNOT_PIPE());
+};
+function writeAfterEnd(stream, cb) {
+  var er = new ERR_STREAM_WRITE_AFTER_END();
+  // TODO: defer error events consistently everywhere, not just the cb
+  errorOrDestroy(stream, er);
+  process.nextTick(cb, er);
+}
+
+// Checks that a user-supplied chunk is valid, especially for the particular
+// mode the stream is in. Currently this means that `null` is never accepted
+// and undefined/non-string values are only allowed in object mode.
+function validChunk(stream, state, chunk, cb) {
+  var er;
+  if (chunk === null) {
+    er = new ERR_STREAM_NULL_VALUES();
+  } else if (typeof chunk !== 'string' && !state.objectMode) {
+    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
+  }
+  if (er) {
+    errorOrDestroy(stream, er);
+    process.nextTick(cb, er);
+    return false;
+  }
+  return true;
+}
+Writable.prototype.write = function (chunk, encoding, cb) {
+  var state = this._writableState;
+  var ret = false;
+  var isBuf = !state.objectMode && _isUint8Array(chunk);
+  if (isBuf && !Buffer.isBuffer(chunk)) {
+    chunk = _uint8ArrayToBuffer(chunk);
+  }
+  if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+  if (isBuf) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;
+  if (typeof cb !== 'function') cb = nop;
+  if (state.ending) writeAfterEnd(this, cb);else if (isBuf || validChunk(this, state, chunk, cb)) {
+    state.pendingcb++;
+    ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
+  }
+  return ret;
+};
+Writable.prototype.cork = function () {
+  this._writableState.corked++;
+};
+Writable.prototype.uncork = function () {
+  var state = this._writableState;
+  if (state.corked) {
+    state.corked--;
+    if (!state.writing && !state.corked && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
+  }
+};
+Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
+  // node::ParseEncoding() requires lower case.
+  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
+  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new ERR_UNKNOWN_ENCODING(encoding);
+  this._writableState.defaultEncoding = encoding;
+  return this;
+};
+Object.defineProperty(Writable.prototype, 'writableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState && this._writableState.getBuffer();
+  }
+});
+function decodeChunk(state, chunk, encoding) {
+  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
+    chunk = Buffer.from(chunk, encoding);
+  }
+  return chunk;
+}
+Object.defineProperty(Writable.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.highWaterMark;
+  }
+});
+
+// if we're already writing something, then just put this
+// in the queue, and wait our turn.  Otherwise, call _write
+// If we return false, then we need a drain event, so set that flag.
+function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
+  if (!isBuf) {
+    var newChunk = decodeChunk(state, chunk, encoding);
+    if (chunk !== newChunk) {
+      isBuf = true;
+      encoding = 'buffer';
+      chunk = newChunk;
+    }
+  }
+  var len = state.objectMode ? 1 : chunk.length;
+  state.length += len;
+  var ret = state.length < state.highWaterMark;
+  // we must ensure that previous needDrain will not be reset to false.
+  if (!ret) state.needDrain = true;
+  if (state.writing || state.corked) {
+    var last = state.lastBufferedRequest;
+    state.lastBufferedRequest = {
+      chunk: chunk,
+      encoding: encoding,
+      isBuf: isBuf,
+      callback: cb,
+      next: null
+    };
+    if (last) {
+      last.next = state.lastBufferedRequest;
+    } else {
+      state.bufferedRequest = state.lastBufferedRequest;
+    }
+    state.bufferedRequestCount += 1;
+  } else {
+    doWrite(stream, state, false, len, chunk, encoding, cb);
+  }
+  return ret;
+}
+function doWrite(stream, state, writev, len, chunk, encoding, cb) {
+  state.writelen = len;
+  state.writecb = cb;
+  state.writing = true;
+  state.sync = true;
+  if (state.destroyed) state.onwrite(new ERR_STREAM_DESTROYED('write'));else if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
+  state.sync = false;
+}
+function onwriteError(stream, state, sync, er, cb) {
+  --state.pendingcb;
+  if (sync) {
+    // defer the callback if we are being called synchronously
+    // to avoid piling up things on the stack
+    process.nextTick(cb, er);
+    // this can emit finish, and it will always happen
+    // after error
+    process.nextTick(finishMaybe, stream, state);
+    stream._writableState.errorEmitted = true;
+    errorOrDestroy(stream, er);
+  } else {
+    // the caller expect this to happen before if
+    // it is async
+    cb(er);
+    stream._writableState.errorEmitted = true;
+    errorOrDestroy(stream, er);
+    // this can emit finish, but finish must
+    // always follow error
+    finishMaybe(stream, state);
+  }
+}
+function onwriteStateUpdate(state) {
+  state.writing = false;
+  state.writecb = null;
+  state.length -= state.writelen;
+  state.writelen = 0;
+}
+function onwrite(stream, er) {
+  var state = stream._writableState;
+  var sync = state.sync;
+  var cb = state.writecb;
+  if (typeof cb !== 'function') throw new ERR_MULTIPLE_CALLBACK();
+  onwriteStateUpdate(state);
+  if (er) onwriteError(stream, state, sync, er, cb);else {
+    // Check if we're actually ready to finish, but don't emit yet
+    var finished = needFinish(state) || stream.destroyed;
+    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
+      clearBuffer(stream, state);
+    }
+    if (sync) {
+      process.nextTick(afterWrite, stream, state, finished, cb);
+    } else {
+      afterWrite(stream, state, finished, cb);
+    }
+  }
+}
+function afterWrite(stream, state, finished, cb) {
+  if (!finished) onwriteDrain(stream, state);
+  state.pendingcb--;
+  cb();
+  finishMaybe(stream, state);
+}
+
+// Must force callback to be called on nextTick, so that we don't
+// emit 'drain' before the write() consumer gets the 'false' return
+// value, and has a chance to attach a 'drain' listener.
+function onwriteDrain(stream, state) {
+  if (state.length === 0 && state.needDrain) {
+    state.needDrain = false;
+    stream.emit('drain');
+  }
+}
+
+// if there's something in the buffer waiting, then process it
+function clearBuffer(stream, state) {
+  state.bufferProcessing = true;
+  var entry = state.bufferedRequest;
+  if (stream._writev && entry && entry.next) {
+    // Fast case, write everything using _writev()
+    var l = state.bufferedRequestCount;
+    var buffer = new Array(l);
+    var holder = state.corkedRequestsFree;
+    holder.entry = entry;
+    var count = 0;
+    var allBuffers = true;
+    while (entry) {
+      buffer[count] = entry;
+      if (!entry.isBuf) allBuffers = false;
+      entry = entry.next;
+      count += 1;
+    }
+    buffer.allBuffers = allBuffers;
+    doWrite(stream, state, true, state.length, buffer, '', holder.finish);
+
+    // doWrite is almost always async, defer these to save a bit of time
+    // as the hot path ends with doWrite
+    state.pendingcb++;
+    state.lastBufferedRequest = null;
+    if (holder.next) {
+      state.corkedRequestsFree = holder.next;
+      holder.next = null;
+    } else {
+      state.corkedRequestsFree = new CorkedRequest(state);
+    }
+    state.bufferedRequestCount = 0;
+  } else {
+    // Slow case, write chunks one-by-one
+    while (entry) {
+      var chunk = entry.chunk;
+      var encoding = entry.encoding;
+      var cb = entry.callback;
+      var len = state.objectMode ? 1 : chunk.length;
+      doWrite(stream, state, false, len, chunk, encoding, cb);
+      entry = entry.next;
+      state.bufferedRequestCount--;
+      // if we didn't call the onwrite immediately, then
+      // it means that we need to wait until it does.
+      // also, that means that the chunk and cb are currently
+      // being processed, so move the buffer counter past them.
+      if (state.writing) {
+        break;
+      }
+    }
+    if (entry === null) state.lastBufferedRequest = null;
+  }
+  state.bufferedRequest = entry;
+  state.bufferProcessing = false;
+}
+Writable.prototype._write = function (chunk, encoding, cb) {
+  cb(new ERR_METHOD_NOT_IMPLEMENTED('_write()'));
+};
+Writable.prototype._writev = null;
+Writable.prototype.end = function (chunk, encoding, cb) {
+  var state = this._writableState;
+  if (typeof chunk === 'function') {
+    cb = chunk;
+    chunk = null;
+    encoding = null;
+  } else if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding);
+
+  // .end() fully uncorks
+  if (state.corked) {
+    state.corked = 1;
+    this.uncork();
+  }
+
+  // ignore unnecessary end() calls.
+  if (!state.ending) endWritable(this, state, cb);
+  return this;
+};
+Object.defineProperty(Writable.prototype, 'writableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.length;
+  }
+});
+function needFinish(state) {
+  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
+}
+function callFinal(stream, state) {
+  stream._final(function (err) {
+    state.pendingcb--;
+    if (err) {
+      errorOrDestroy(stream, err);
+    }
+    state.prefinished = true;
+    stream.emit('prefinish');
+    finishMaybe(stream, state);
+  });
+}
+function prefinish(stream, state) {
+  if (!state.prefinished && !state.finalCalled) {
+    if (typeof stream._final === 'function' && !state.destroyed) {
+      state.pendingcb++;
+      state.finalCalled = true;
+      process.nextTick(callFinal, stream, state);
+    } else {
+      state.prefinished = true;
+      stream.emit('prefinish');
+    }
+  }
+}
+function finishMaybe(stream, state) {
+  var need = needFinish(state);
+  if (need) {
+    prefinish(stream, state);
+    if (state.pendingcb === 0) {
+      state.finished = true;
+      stream.emit('finish');
+      if (state.autoDestroy) {
+        // In case of duplex streams we need a way to detect
+        // if the readable side is ready for autoDestroy as well
+        var rState = stream._readableState;
+        if (!rState || rState.autoDestroy && rState.endEmitted) {
+          stream.destroy();
+        }
+      }
+    }
+  }
+  return need;
+}
+function endWritable(stream, state, cb) {
+  state.ending = true;
+  finishMaybe(stream, state);
+  if (cb) {
+    if (state.finished) process.nextTick(cb);else stream.once('finish', cb);
+  }
+  state.ended = true;
+  stream.writable = false;
+}
+function onCorkedFinish(corkReq, state, err) {
+  var entry = corkReq.entry;
+  corkReq.entry = null;
+  while (entry) {
+    var cb = entry.callback;
+    state.pendingcb--;
+    cb(err);
+    entry = entry.next;
+  }
+
+  // reuse the free corkReq.
+  state.corkedRequestsFree.next = corkReq;
+}
+Object.defineProperty(Writable.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._writableState === undefined) {
+      return false;
+    }
+    return this._writableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._writableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._writableState.destroyed = value;
+  }
+});
+Writable.prototype.destroy = destroyImpl.destroy;
+Writable.prototype._undestroy = destroyImpl.undestroy;
+Writable.prototype._destroy = function (err, cb) {
+  cb(err);
+};
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/async_iterator.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/async_iterator.js
new file mode 100644
index 0000000..742c5a4
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/async_iterator.js
@@ -0,0 +1,180 @@
+'use strict';
+
+var _Object$setPrototypeO;
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+var finished = require('./end-of-stream');
+var kLastResolve = Symbol('lastResolve');
+var kLastReject = Symbol('lastReject');
+var kError = Symbol('error');
+var kEnded = Symbol('ended');
+var kLastPromise = Symbol('lastPromise');
+var kHandlePromise = Symbol('handlePromise');
+var kStream = Symbol('stream');
+function createIterResult(value, done) {
+  return {
+    value: value,
+    done: done
+  };
+}
+function readAndResolve(iter) {
+  var resolve = iter[kLastResolve];
+  if (resolve !== null) {
+    var data = iter[kStream].read();
+    // we defer if data is null
+    // we can be expecting either 'end' or
+    // 'error'
+    if (data !== null) {
+      iter[kLastPromise] = null;
+      iter[kLastResolve] = null;
+      iter[kLastReject] = null;
+      resolve(createIterResult(data, false));
+    }
+  }
+}
+function onReadable(iter) {
+  // we wait for the next tick, because it might
+  // emit an error with process.nextTick
+  process.nextTick(readAndResolve, iter);
+}
+function wrapForNext(lastPromise, iter) {
+  return function (resolve, reject) {
+    lastPromise.then(function () {
+      if (iter[kEnded]) {
+        resolve(createIterResult(undefined, true));
+        return;
+      }
+      iter[kHandlePromise](resolve, reject);
+    }, reject);
+  };
+}
+var AsyncIteratorPrototype = Object.getPrototypeOf(function () {});
+var ReadableStreamAsyncIteratorPrototype = Object.setPrototypeOf((_Object$setPrototypeO = {
+  get stream() {
+    return this[kStream];
+  },
+  next: function next() {
+    var _this = this;
+    // if we have detected an error in the meanwhile
+    // reject straight away
+    var error = this[kError];
+    if (error !== null) {
+      return Promise.reject(error);
+    }
+    if (this[kEnded]) {
+      return Promise.resolve(createIterResult(undefined, true));
+    }
+    if (this[kStream].destroyed) {
+      // We need to defer via nextTick because if .destroy(err) is
+      // called, the error will be emitted via nextTick, and
+      // we cannot guarantee that there is no error lingering around
+      // waiting to be emitted.
+      return new Promise(function (resolve, reject) {
+        process.nextTick(function () {
+          if (_this[kError]) {
+            reject(_this[kError]);
+          } else {
+            resolve(createIterResult(undefined, true));
+          }
+        });
+      });
+    }
+
+    // if we have multiple next() calls
+    // we will wait for the previous Promise to finish
+    // this logic is optimized to support for await loops,
+    // where next() is only called once at a time
+    var lastPromise = this[kLastPromise];
+    var promise;
+    if (lastPromise) {
+      promise = new Promise(wrapForNext(lastPromise, this));
+    } else {
+      // fast path needed to support multiple this.push()
+      // without triggering the next() queue
+      var data = this[kStream].read();
+      if (data !== null) {
+        return Promise.resolve(createIterResult(data, false));
+      }
+      promise = new Promise(this[kHandlePromise]);
+    }
+    this[kLastPromise] = promise;
+    return promise;
+  }
+}, _defineProperty(_Object$setPrototypeO, Symbol.asyncIterator, function () {
+  return this;
+}), _defineProperty(_Object$setPrototypeO, "return", function _return() {
+  var _this2 = this;
+  // destroy(err, cb) is a private API
+  // we can guarantee we have that here, because we control the
+  // Readable class this is attached to
+  return new Promise(function (resolve, reject) {
+    _this2[kStream].destroy(null, function (err) {
+      if (err) {
+        reject(err);
+        return;
+      }
+      resolve(createIterResult(undefined, true));
+    });
+  });
+}), _Object$setPrototypeO), AsyncIteratorPrototype);
+var createReadableStreamAsyncIterator = function createReadableStreamAsyncIterator(stream) {
+  var _Object$create;
+  var iterator = Object.create(ReadableStreamAsyncIteratorPrototype, (_Object$create = {}, _defineProperty(_Object$create, kStream, {
+    value: stream,
+    writable: true
+  }), _defineProperty(_Object$create, kLastResolve, {
+    value: null,
+    writable: true
+  }), _defineProperty(_Object$create, kLastReject, {
+    value: null,
+    writable: true
+  }), _defineProperty(_Object$create, kError, {
+    value: null,
+    writable: true
+  }), _defineProperty(_Object$create, kEnded, {
+    value: stream._readableState.endEmitted,
+    writable: true
+  }), _defineProperty(_Object$create, kHandlePromise, {
+    value: function value(resolve, reject) {
+      var data = iterator[kStream].read();
+      if (data) {
+        iterator[kLastPromise] = null;
+        iterator[kLastResolve] = null;
+        iterator[kLastReject] = null;
+        resolve(createIterResult(data, false));
+      } else {
+        iterator[kLastResolve] = resolve;
+        iterator[kLastReject] = reject;
+      }
+    },
+    writable: true
+  }), _Object$create));
+  iterator[kLastPromise] = null;
+  finished(stream, function (err) {
+    if (err && err.code !== 'ERR_STREAM_PREMATURE_CLOSE') {
+      var reject = iterator[kLastReject];
+      // reject if we are waiting for data in the Promise
+      // returned by next() and store the error
+      if (reject !== null) {
+        iterator[kLastPromise] = null;
+        iterator[kLastResolve] = null;
+        iterator[kLastReject] = null;
+        reject(err);
+      }
+      iterator[kError] = err;
+      return;
+    }
+    var resolve = iterator[kLastResolve];
+    if (resolve !== null) {
+      iterator[kLastPromise] = null;
+      iterator[kLastResolve] = null;
+      iterator[kLastReject] = null;
+      resolve(createIterResult(undefined, true));
+    }
+    iterator[kEnded] = true;
+  });
+  stream.on('readable', onReadable.bind(null, iterator));
+  return iterator;
+};
+module.exports = createReadableStreamAsyncIterator;
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/buffer_list.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/buffer_list.js
new file mode 100644
index 0000000..69bda49
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/buffer_list.js
@@ -0,0 +1,183 @@
+'use strict';
+
+function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); enumerableOnly && (symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; })), keys.push.apply(keys, symbols); } return keys; }
+function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = null != arguments[i] ? arguments[i] : {}; i % 2 ? ownKeys(Object(source), !0).forEach(function (key) { _defineProperty(target, key, source[key]); }) : Object.getOwnPropertyDescriptors ? Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)) : ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } return target; }
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, _toPropertyKey(descriptor.key), descriptor); } }
+function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+var _require = require('buffer'),
+  Buffer = _require.Buffer;
+var _require2 = require('util'),
+  inspect = _require2.inspect;
+var custom = inspect && inspect.custom || 'inspect';
+function copyBuffer(src, target, offset) {
+  Buffer.prototype.copy.call(src, target, offset);
+}
+module.exports = /*#__PURE__*/function () {
+  function BufferList() {
+    _classCallCheck(this, BufferList);
+    this.head = null;
+    this.tail = null;
+    this.length = 0;
+  }
+  _createClass(BufferList, [{
+    key: "push",
+    value: function push(v) {
+      var entry = {
+        data: v,
+        next: null
+      };
+      if (this.length > 0) this.tail.next = entry;else this.head = entry;
+      this.tail = entry;
+      ++this.length;
+    }
+  }, {
+    key: "unshift",
+    value: function unshift(v) {
+      var entry = {
+        data: v,
+        next: this.head
+      };
+      if (this.length === 0) this.tail = entry;
+      this.head = entry;
+      ++this.length;
+    }
+  }, {
+    key: "shift",
+    value: function shift() {
+      if (this.length === 0) return;
+      var ret = this.head.data;
+      if (this.length === 1) this.head = this.tail = null;else this.head = this.head.next;
+      --this.length;
+      return ret;
+    }
+  }, {
+    key: "clear",
+    value: function clear() {
+      this.head = this.tail = null;
+      this.length = 0;
+    }
+  }, {
+    key: "join",
+    value: function join(s) {
+      if (this.length === 0) return '';
+      var p = this.head;
+      var ret = '' + p.data;
+      while (p = p.next) ret += s + p.data;
+      return ret;
+    }
+  }, {
+    key: "concat",
+    value: function concat(n) {
+      if (this.length === 0) return Buffer.alloc(0);
+      var ret = Buffer.allocUnsafe(n >>> 0);
+      var p = this.head;
+      var i = 0;
+      while (p) {
+        copyBuffer(p.data, ret, i);
+        i += p.data.length;
+        p = p.next;
+      }
+      return ret;
+    }
+
+    // Consumes a specified amount of bytes or characters from the buffered data.
+  }, {
+    key: "consume",
+    value: function consume(n, hasStrings) {
+      var ret;
+      if (n < this.head.data.length) {
+        // `slice` is the same for buffers and strings.
+        ret = this.head.data.slice(0, n);
+        this.head.data = this.head.data.slice(n);
+      } else if (n === this.head.data.length) {
+        // First chunk is a perfect match.
+        ret = this.shift();
+      } else {
+        // Result spans more than one buffer.
+        ret = hasStrings ? this._getString(n) : this._getBuffer(n);
+      }
+      return ret;
+    }
+  }, {
+    key: "first",
+    value: function first() {
+      return this.head.data;
+    }
+
+    // Consumes a specified amount of characters from the buffered data.
+  }, {
+    key: "_getString",
+    value: function _getString(n) {
+      var p = this.head;
+      var c = 1;
+      var ret = p.data;
+      n -= ret.length;
+      while (p = p.next) {
+        var str = p.data;
+        var nb = n > str.length ? str.length : n;
+        if (nb === str.length) ret += str;else ret += str.slice(0, n);
+        n -= nb;
+        if (n === 0) {
+          if (nb === str.length) {
+            ++c;
+            if (p.next) this.head = p.next;else this.head = this.tail = null;
+          } else {
+            this.head = p;
+            p.data = str.slice(nb);
+          }
+          break;
+        }
+        ++c;
+      }
+      this.length -= c;
+      return ret;
+    }
+
+    // Consumes a specified amount of bytes from the buffered data.
+  }, {
+    key: "_getBuffer",
+    value: function _getBuffer(n) {
+      var ret = Buffer.allocUnsafe(n);
+      var p = this.head;
+      var c = 1;
+      p.data.copy(ret);
+      n -= p.data.length;
+      while (p = p.next) {
+        var buf = p.data;
+        var nb = n > buf.length ? buf.length : n;
+        buf.copy(ret, ret.length - n, 0, nb);
+        n -= nb;
+        if (n === 0) {
+          if (nb === buf.length) {
+            ++c;
+            if (p.next) this.head = p.next;else this.head = this.tail = null;
+          } else {
+            this.head = p;
+            p.data = buf.slice(nb);
+          }
+          break;
+        }
+        ++c;
+      }
+      this.length -= c;
+      return ret;
+    }
+
+    // Make sure the linked list only shows the minimal necessary information.
+  }, {
+    key: custom,
+    value: function value(_, options) {
+      return inspect(this, _objectSpread(_objectSpread({}, options), {}, {
+        // Only inspect one level.
+        depth: 0,
+        // It should not recurse.
+        customInspect: false
+      }));
+    }
+  }]);
+  return BufferList;
+}();
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/destroy.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/destroy.js
new file mode 100644
index 0000000..31a17c4
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/destroy.js
@@ -0,0 +1,96 @@
+'use strict';
+
+// undocumented cb() API, needed for core, not for public API
+function destroy(err, cb) {
+  var _this = this;
+  var readableDestroyed = this._readableState && this._readableState.destroyed;
+  var writableDestroyed = this._writableState && this._writableState.destroyed;
+  if (readableDestroyed || writableDestroyed) {
+    if (cb) {
+      cb(err);
+    } else if (err) {
+      if (!this._writableState) {
+        process.nextTick(emitErrorNT, this, err);
+      } else if (!this._writableState.errorEmitted) {
+        this._writableState.errorEmitted = true;
+        process.nextTick(emitErrorNT, this, err);
+      }
+    }
+    return this;
+  }
+
+  // we set destroyed to true before firing error callbacks in order
+  // to make it re-entrance safe in case destroy() is called within callbacks
+
+  if (this._readableState) {
+    this._readableState.destroyed = true;
+  }
+
+  // if this is a duplex stream mark the writable part as destroyed as well
+  if (this._writableState) {
+    this._writableState.destroyed = true;
+  }
+  this._destroy(err || null, function (err) {
+    if (!cb && err) {
+      if (!_this._writableState) {
+        process.nextTick(emitErrorAndCloseNT, _this, err);
+      } else if (!_this._writableState.errorEmitted) {
+        _this._writableState.errorEmitted = true;
+        process.nextTick(emitErrorAndCloseNT, _this, err);
+      } else {
+        process.nextTick(emitCloseNT, _this);
+      }
+    } else if (cb) {
+      process.nextTick(emitCloseNT, _this);
+      cb(err);
+    } else {
+      process.nextTick(emitCloseNT, _this);
+    }
+  });
+  return this;
+}
+function emitErrorAndCloseNT(self, err) {
+  emitErrorNT(self, err);
+  emitCloseNT(self);
+}
+function emitCloseNT(self) {
+  if (self._writableState && !self._writableState.emitClose) return;
+  if (self._readableState && !self._readableState.emitClose) return;
+  self.emit('close');
+}
+function undestroy() {
+  if (this._readableState) {
+    this._readableState.destroyed = false;
+    this._readableState.reading = false;
+    this._readableState.ended = false;
+    this._readableState.endEmitted = false;
+  }
+  if (this._writableState) {
+    this._writableState.destroyed = false;
+    this._writableState.ended = false;
+    this._writableState.ending = false;
+    this._writableState.finalCalled = false;
+    this._writableState.prefinished = false;
+    this._writableState.finished = false;
+    this._writableState.errorEmitted = false;
+  }
+}
+function emitErrorNT(self, err) {
+  self.emit('error', err);
+}
+function errorOrDestroy(stream, err) {
+  // We have tests that rely on errors being emitted
+  // in the same tick, so changing this is semver major.
+  // For now when you opt-in to autoDestroy we allow
+  // the error to be emitted nextTick. In a future
+  // semver major update we should change the default to this.
+
+  var rState = stream._readableState;
+  var wState = stream._writableState;
+  if (rState && rState.autoDestroy || wState && wState.autoDestroy) stream.destroy(err);else stream.emit('error', err);
+}
+module.exports = {
+  destroy: destroy,
+  undestroy: undestroy,
+  errorOrDestroy: errorOrDestroy
+};
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/end-of-stream.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/end-of-stream.js
new file mode 100644
index 0000000..59c671b
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/end-of-stream.js
@@ -0,0 +1,86 @@
+// Ported from https://github.com/mafintosh/end-of-stream with
+// permission from the author, Mathias Buus (@mafintosh).
+
+'use strict';
+
+var ERR_STREAM_PREMATURE_CLOSE = require('../../../errors').codes.ERR_STREAM_PREMATURE_CLOSE;
+function once(callback) {
+  var called = false;
+  return function () {
+    if (called) return;
+    called = true;
+    for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
+      args[_key] = arguments[_key];
+    }
+    callback.apply(this, args);
+  };
+}
+function noop() {}
+function isRequest(stream) {
+  return stream.setHeader && typeof stream.abort === 'function';
+}
+function eos(stream, opts, callback) {
+  if (typeof opts === 'function') return eos(stream, null, opts);
+  if (!opts) opts = {};
+  callback = once(callback || noop);
+  var readable = opts.readable || opts.readable !== false && stream.readable;
+  var writable = opts.writable || opts.writable !== false && stream.writable;
+  var onlegacyfinish = function onlegacyfinish() {
+    if (!stream.writable) onfinish();
+  };
+  var writableEnded = stream._writableState && stream._writableState.finished;
+  var onfinish = function onfinish() {
+    writable = false;
+    writableEnded = true;
+    if (!readable) callback.call(stream);
+  };
+  var readableEnded = stream._readableState && stream._readableState.endEmitted;
+  var onend = function onend() {
+    readable = false;
+    readableEnded = true;
+    if (!writable) callback.call(stream);
+  };
+  var onerror = function onerror(err) {
+    callback.call(stream, err);
+  };
+  var onclose = function onclose() {
+    var err;
+    if (readable && !readableEnded) {
+      if (!stream._readableState || !stream._readableState.ended) err = new ERR_STREAM_PREMATURE_CLOSE();
+      return callback.call(stream, err);
+    }
+    if (writable && !writableEnded) {
+      if (!stream._writableState || !stream._writableState.ended) err = new ERR_STREAM_PREMATURE_CLOSE();
+      return callback.call(stream, err);
+    }
+  };
+  var onrequest = function onrequest() {
+    stream.req.on('finish', onfinish);
+  };
+  if (isRequest(stream)) {
+    stream.on('complete', onfinish);
+    stream.on('abort', onclose);
+    if (stream.req) onrequest();else stream.on('request', onrequest);
+  } else if (writable && !stream._writableState) {
+    // legacy streams
+    stream.on('end', onlegacyfinish);
+    stream.on('close', onlegacyfinish);
+  }
+  stream.on('end', onend);
+  stream.on('finish', onfinish);
+  if (opts.error !== false) stream.on('error', onerror);
+  stream.on('close', onclose);
+  return function () {
+    stream.removeListener('complete', onfinish);
+    stream.removeListener('abort', onclose);
+    stream.removeListener('request', onrequest);
+    if (stream.req) stream.req.removeListener('finish', onfinish);
+    stream.removeListener('end', onlegacyfinish);
+    stream.removeListener('close', onlegacyfinish);
+    stream.removeListener('finish', onfinish);
+    stream.removeListener('end', onend);
+    stream.removeListener('error', onerror);
+    stream.removeListener('close', onclose);
+  };
+}
+module.exports = eos;
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/from-browser.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/from-browser.js
new file mode 100644
index 0000000..a4ce56f
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/from-browser.js
@@ -0,0 +1,3 @@
+module.exports = function () {
+  throw new Error('Readable.from is not available in the browser')
+};
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/from.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/from.js
new file mode 100644
index 0000000..0a34ee9
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/from.js
@@ -0,0 +1,52 @@
+'use strict';
+
+function asyncGeneratorStep(gen, resolve, reject, _next, _throw, key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { Promise.resolve(value).then(_next, _throw); } }
+function _asyncToGenerator(fn) { return function () { var self = this, args = arguments; return new Promise(function (resolve, reject) { var gen = fn.apply(self, args); function _next(value) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "next", value); } function _throw(err) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "throw", err); } _next(undefined); }); }; }
+function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); enumerableOnly && (symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; })), keys.push.apply(keys, symbols); } return keys; }
+function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = null != arguments[i] ? arguments[i] : {}; i % 2 ? ownKeys(Object(source), !0).forEach(function (key) { _defineProperty(target, key, source[key]); }) : Object.getOwnPropertyDescriptors ? Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)) : ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } return target; }
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+var ERR_INVALID_ARG_TYPE = require('../../../errors').codes.ERR_INVALID_ARG_TYPE;
+function from(Readable, iterable, opts) {
+  var iterator;
+  if (iterable && typeof iterable.next === 'function') {
+    iterator = iterable;
+  } else if (iterable && iterable[Symbol.asyncIterator]) iterator = iterable[Symbol.asyncIterator]();else if (iterable && iterable[Symbol.iterator]) iterator = iterable[Symbol.iterator]();else throw new ERR_INVALID_ARG_TYPE('iterable', ['Iterable'], iterable);
+  var readable = new Readable(_objectSpread({
+    objectMode: true
+  }, opts));
+  // Reading boolean to protect against _read
+  // being called before last iteration completion.
+  var reading = false;
+  readable._read = function () {
+    if (!reading) {
+      reading = true;
+      next();
+    }
+  };
+  function next() {
+    return _next2.apply(this, arguments);
+  }
+  function _next2() {
+    _next2 = _asyncToGenerator(function* () {
+      try {
+        var _yield$iterator$next = yield iterator.next(),
+          value = _yield$iterator$next.value,
+          done = _yield$iterator$next.done;
+        if (done) {
+          readable.push(null);
+        } else if (readable.push(yield value)) {
+          next();
+        } else {
+          reading = false;
+        }
+      } catch (err) {
+        readable.destroy(err);
+      }
+    });
+    return _next2.apply(this, arguments);
+  }
+  return readable;
+}
+module.exports = from;
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/pipeline.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/pipeline.js
new file mode 100644
index 0000000..e6f3924
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/pipeline.js
@@ -0,0 +1,86 @@
+// Ported from https://github.com/mafintosh/pump with
+// permission from the author, Mathias Buus (@mafintosh).
+
+'use strict';
+
+var eos;
+function once(callback) {
+  var called = false;
+  return function () {
+    if (called) return;
+    called = true;
+    callback.apply(void 0, arguments);
+  };
+}
+var _require$codes = require('../../../errors').codes,
+  ERR_MISSING_ARGS = _require$codes.ERR_MISSING_ARGS,
+  ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED;
+function noop(err) {
+  // Rethrow the error if it exists to avoid swallowing it
+  if (err) throw err;
+}
+function isRequest(stream) {
+  return stream.setHeader && typeof stream.abort === 'function';
+}
+function destroyer(stream, reading, writing, callback) {
+  callback = once(callback);
+  var closed = false;
+  stream.on('close', function () {
+    closed = true;
+  });
+  if (eos === undefined) eos = require('./end-of-stream');
+  eos(stream, {
+    readable: reading,
+    writable: writing
+  }, function (err) {
+    if (err) return callback(err);
+    closed = true;
+    callback();
+  });
+  var destroyed = false;
+  return function (err) {
+    if (closed) return;
+    if (destroyed) return;
+    destroyed = true;
+
+    // request.destroy just do .end - .abort is what we want
+    if (isRequest(stream)) return stream.abort();
+    if (typeof stream.destroy === 'function') return stream.destroy();
+    callback(err || new ERR_STREAM_DESTROYED('pipe'));
+  };
+}
+function call(fn) {
+  fn();
+}
+function pipe(from, to) {
+  return from.pipe(to);
+}
+function popCallback(streams) {
+  if (!streams.length) return noop;
+  if (typeof streams[streams.length - 1] !== 'function') return noop;
+  return streams.pop();
+}
+function pipeline() {
+  for (var _len = arguments.length, streams = new Array(_len), _key = 0; _key < _len; _key++) {
+    streams[_key] = arguments[_key];
+  }
+  var callback = popCallback(streams);
+  if (Array.isArray(streams[0])) streams = streams[0];
+  if (streams.length < 2) {
+    throw new ERR_MISSING_ARGS('streams');
+  }
+  var error;
+  var destroys = streams.map(function (stream, i) {
+    var reading = i < streams.length - 1;
+    var writing = i > 0;
+    return destroyer(stream, reading, writing, function (err) {
+      if (!error) error = err;
+      if (err) destroys.forEach(call);
+      if (reading) return;
+      destroys.forEach(call);
+      callback(error);
+    });
+  });
+  return streams.reduce(pipe);
+}
+module.exports = pipeline;
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/state.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/state.js
new file mode 100644
index 0000000..3fbf892
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/state.js
@@ -0,0 +1,22 @@
+'use strict';
+
+var ERR_INVALID_OPT_VALUE = require('../../../errors').codes.ERR_INVALID_OPT_VALUE;
+function highWaterMarkFrom(options, isDuplex, duplexKey) {
+  return options.highWaterMark != null ? options.highWaterMark : isDuplex ? options[duplexKey] : null;
+}
+function getHighWaterMark(state, options, duplexKey, isDuplex) {
+  var hwm = highWaterMarkFrom(options, isDuplex, duplexKey);
+  if (hwm != null) {
+    if (!(isFinite(hwm) && Math.floor(hwm) === hwm) || hwm < 0) {
+      var name = isDuplex ? duplexKey : 'highWaterMark';
+      throw new ERR_INVALID_OPT_VALUE(name, hwm);
+    }
+    return Math.floor(hwm);
+  }
+
+  // Default value
+  return state.objectMode ? 16 : 16 * 1024;
+}
+module.exports = {
+  getHighWaterMark: getHighWaterMark
+};
\ No newline at end of file
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/stream-browser.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/stream-browser.js
new file mode 100644
index 0000000..9332a3f
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/stream-browser.js
@@ -0,0 +1 @@
+module.exports = require('events').EventEmitter;
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/stream.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/stream.js
new file mode 100644
index 0000000..ce2ad5b
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/lib/internal/streams/stream.js
@@ -0,0 +1 @@
+module.exports = require('stream');
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/package.json b/server/node_modules/are-we-there-yet/node_modules/readable-stream/package.json
new file mode 100644
index 0000000..ade59e7
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/package.json
@@ -0,0 +1,68 @@
+{
+  "name": "readable-stream",
+  "version": "3.6.2",
+  "description": "Streams3, a user-land copy of the stream library from Node.js",
+  "main": "readable.js",
+  "engines": {
+    "node": ">= 6"
+  },
+  "dependencies": {
+    "inherits": "^2.0.3",
+    "string_decoder": "^1.1.1",
+    "util-deprecate": "^1.0.1"
+  },
+  "devDependencies": {
+    "@babel/cli": "^7.2.0",
+    "@babel/core": "^7.2.0",
+    "@babel/polyfill": "^7.0.0",
+    "@babel/preset-env": "^7.2.0",
+    "airtap": "0.0.9",
+    "assert": "^1.4.0",
+    "bl": "^2.0.0",
+    "deep-strict-equal": "^0.2.0",
+    "events.once": "^2.0.2",
+    "glob": "^7.1.2",
+    "gunzip-maybe": "^1.4.1",
+    "hyperquest": "^2.1.3",
+    "lolex": "^2.6.0",
+    "nyc": "^11.0.0",
+    "pump": "^3.0.0",
+    "rimraf": "^2.6.2",
+    "tap": "^12.0.0",
+    "tape": "^4.9.0",
+    "tar-fs": "^1.16.2",
+    "util-promisify": "^2.1.0"
+  },
+  "scripts": {
+    "test": "tap -J --no-esm test/parallel/*.js test/ours/*.js",
+    "ci": "TAP=1 tap --no-esm test/parallel/*.js test/ours/*.js | tee test.tap",
+    "test-browsers": "airtap --sauce-connect --loopback airtap.local -- test/browser.js",
+    "test-browser-local": "airtap --open --local -- test/browser.js",
+    "cover": "nyc npm test",
+    "report": "nyc report --reporter=lcov",
+    "update-browser-errors": "babel -o errors-browser.js errors.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/nodejs/readable-stream"
+  },
+  "keywords": [
+    "readable",
+    "stream",
+    "pipe"
+  ],
+  "browser": {
+    "util": false,
+    "worker_threads": false,
+    "./errors": "./errors-browser.js",
+    "./readable.js": "./readable-browser.js",
+    "./lib/internal/streams/from.js": "./lib/internal/streams/from-browser.js",
+    "./lib/internal/streams/stream.js": "./lib/internal/streams/stream-browser.js"
+  },
+  "nyc": {
+    "include": [
+      "lib/**.js"
+    ]
+  },
+  "license": "MIT"
+}
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/readable-browser.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/readable-browser.js
new file mode 100644
index 0000000..adbf60d
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/readable-browser.js
@@ -0,0 +1,9 @@
+exports = module.exports = require('./lib/_stream_readable.js');
+exports.Stream = exports;
+exports.Readable = exports;
+exports.Writable = require('./lib/_stream_writable.js');
+exports.Duplex = require('./lib/_stream_duplex.js');
+exports.Transform = require('./lib/_stream_transform.js');
+exports.PassThrough = require('./lib/_stream_passthrough.js');
+exports.finished = require('./lib/internal/streams/end-of-stream.js');
+exports.pipeline = require('./lib/internal/streams/pipeline.js');
diff --git a/server/node_modules/are-we-there-yet/node_modules/readable-stream/readable.js b/server/node_modules/are-we-there-yet/node_modules/readable-stream/readable.js
new file mode 100644
index 0000000..9e0ca12
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/node_modules/readable-stream/readable.js
@@ -0,0 +1,16 @@
+var Stream = require('stream');
+if (process.env.READABLE_STREAM === 'disable' && Stream) {
+  module.exports = Stream.Readable;
+  Object.assign(module.exports, Stream);
+  module.exports.Stream = Stream;
+} else {
+  exports = module.exports = require('./lib/_stream_readable.js');
+  exports.Stream = Stream || exports;
+  exports.Readable = exports;
+  exports.Writable = require('./lib/_stream_writable.js');
+  exports.Duplex = require('./lib/_stream_duplex.js');
+  exports.Transform = require('./lib/_stream_transform.js');
+  exports.PassThrough = require('./lib/_stream_passthrough.js');
+  exports.finished = require('./lib/internal/streams/end-of-stream.js');
+  exports.pipeline = require('./lib/internal/streams/pipeline.js');
+}
diff --git a/server/node_modules/are-we-there-yet/package.json b/server/node_modules/are-we-there-yet/package.json
new file mode 100644
index 0000000..cc3d750
--- /dev/null
+++ b/server/node_modules/are-we-there-yet/package.json
@@ -0,0 +1,56 @@
+{
+  "name": "are-we-there-yet",
+  "version": "3.0.1",
+  "description": "Keep track of the overall completion of many disparate processes",
+  "main": "lib/index.js",
+  "scripts": {
+    "test": "tap",
+    "npmclilint": "npmcli-lint",
+    "lint": "eslint \"**/*.js\"",
+    "lintfix": "npm run lint -- --fix",
+    "posttest": "npm run lint",
+    "postsnap": "npm run lintfix --",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags",
+    "snap": "tap",
+    "postlint": "template-oss-check",
+    "template-oss-apply": "template-oss-apply --force"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/npm/are-we-there-yet.git"
+  },
+  "author": "GitHub Inc.",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/npm/are-we-there-yet/issues"
+  },
+  "homepage": "https://github.com/npm/are-we-there-yet",
+  "devDependencies": {
+    "@npmcli/eslint-config": "^3.0.1",
+    "@npmcli/template-oss": "3.5.0",
+    "tap": "^16.0.1"
+  },
+  "dependencies": {
+    "delegates": "^1.0.0",
+    "readable-stream": "^3.6.0"
+  },
+  "files": [
+    "bin/",
+    "lib/"
+  ],
+  "engines": {
+    "node": "^12.13.0 || ^14.15.0 || >=16.0.0"
+  },
+  "tap": {
+    "branches": 68,
+    "statements": 92,
+    "functions": 86,
+    "lines": 92
+  },
+  "templateOSS": {
+    "//@npmcli/template-oss": "This file is partially managed by @npmcli/template-oss. Edits may be overwritten.",
+    "version": "3.5.0"
+  }
+}
diff --git a/server/node_modules/array-flatten/LICENSE b/server/node_modules/array-flatten/LICENSE
new file mode 100644
index 0000000..983fbe8
--- /dev/null
+++ b/server/node_modules/array-flatten/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Blake Embrey (hello@blakeembrey.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/array-flatten/README.md b/server/node_modules/array-flatten/README.md
new file mode 100644
index 0000000..91fa5b6
--- /dev/null
+++ b/server/node_modules/array-flatten/README.md
@@ -0,0 +1,43 @@
+# Array Flatten
+
+[![NPM version][npm-image]][npm-url]
+[![NPM downloads][downloads-image]][downloads-url]
+[![Build status][travis-image]][travis-url]
+[![Test coverage][coveralls-image]][coveralls-url]
+
+> Flatten an array of nested arrays into a single flat array. Accepts an optional depth.
+
+## Installation
+
+```
+npm install array-flatten --save
+```
+
+## Usage
+
+```javascript
+var flatten = require('array-flatten')
+
+flatten([1, [2, [3, [4, [5], 6], 7], 8], 9])
+//=> [1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+flatten([1, [2, [3, [4, [5], 6], 7], 8], 9], 2)
+//=> [1, 2, 3, [4, [5], 6], 7, 8, 9]
+
+(function () {
+  flatten(arguments) //=> [1, 2, 3]
+})(1, [2, 3])
+```
+
+## License
+
+MIT
+
+[npm-image]: https://img.shields.io/npm/v/array-flatten.svg?style=flat
+[npm-url]: https://npmjs.org/package/array-flatten
+[downloads-image]: https://img.shields.io/npm/dm/array-flatten.svg?style=flat
+[downloads-url]: https://npmjs.org/package/array-flatten
+[travis-image]: https://img.shields.io/travis/blakeembrey/array-flatten.svg?style=flat
+[travis-url]: https://travis-ci.org/blakeembrey/array-flatten
+[coveralls-image]: https://img.shields.io/coveralls/blakeembrey/array-flatten.svg?style=flat
+[coveralls-url]: https://coveralls.io/r/blakeembrey/array-flatten?branch=master
diff --git a/server/node_modules/array-flatten/array-flatten.js b/server/node_modules/array-flatten/array-flatten.js
new file mode 100644
index 0000000..089117b
--- /dev/null
+++ b/server/node_modules/array-flatten/array-flatten.js
@@ -0,0 +1,64 @@
+'use strict'
+
+/**
+ * Expose `arrayFlatten`.
+ */
+module.exports = arrayFlatten
+
+/**
+ * Recursive flatten function with depth.
+ *
+ * @param  {Array}  array
+ * @param  {Array}  result
+ * @param  {Number} depth
+ * @return {Array}
+ */
+function flattenWithDepth (array, result, depth) {
+  for (var i = 0; i < array.length; i++) {
+    var value = array[i]
+
+    if (depth > 0 && Array.isArray(value)) {
+      flattenWithDepth(value, result, depth - 1)
+    } else {
+      result.push(value)
+    }
+  }
+
+  return result
+}
+
+/**
+ * Recursive flatten function. Omitting depth is slightly faster.
+ *
+ * @param  {Array} array
+ * @param  {Array} result
+ * @return {Array}
+ */
+function flattenForever (array, result) {
+  for (var i = 0; i < array.length; i++) {
+    var value = array[i]
+
+    if (Array.isArray(value)) {
+      flattenForever(value, result)
+    } else {
+      result.push(value)
+    }
+  }
+
+  return result
+}
+
+/**
+ * Flatten an array, with the ability to define a depth.
+ *
+ * @param  {Array}  array
+ * @param  {Number} depth
+ * @return {Array}
+ */
+function arrayFlatten (array, depth) {
+  if (depth == null) {
+    return flattenForever(array, [])
+  }
+
+  return flattenWithDepth(array, [], depth)
+}
diff --git a/server/node_modules/array-flatten/package.json b/server/node_modules/array-flatten/package.json
new file mode 100644
index 0000000..1a24e2a
--- /dev/null
+++ b/server/node_modules/array-flatten/package.json
@@ -0,0 +1,39 @@
+{
+  "name": "array-flatten",
+  "version": "1.1.1",
+  "description": "Flatten an array of nested arrays into a single flat array",
+  "main": "array-flatten.js",
+  "files": [
+    "array-flatten.js",
+    "LICENSE"
+  ],
+  "scripts": {
+    "test": "istanbul cover _mocha -- -R spec"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/blakeembrey/array-flatten.git"
+  },
+  "keywords": [
+    "array",
+    "flatten",
+    "arguments",
+    "depth"
+  ],
+  "author": {
+    "name": "Blake Embrey",
+    "email": "hello@blakeembrey.com",
+    "url": "http://blakeembrey.me"
+  },
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/blakeembrey/array-flatten/issues"
+  },
+  "homepage": "https://github.com/blakeembrey/array-flatten",
+  "devDependencies": {
+    "istanbul": "^0.3.13",
+    "mocha": "^2.2.4",
+    "pre-commit": "^1.0.7",
+    "standard": "^3.7.3"
+  }
+}
diff --git a/server/node_modules/balanced-match/.github/FUNDING.yml b/server/node_modules/balanced-match/.github/FUNDING.yml
new file mode 100644
index 0000000..cea8b16
--- /dev/null
+++ b/server/node_modules/balanced-match/.github/FUNDING.yml
@@ -0,0 +1,2 @@
+tidelift: "npm/balanced-match"
+patreon: juliangruber
diff --git a/server/node_modules/balanced-match/LICENSE.md b/server/node_modules/balanced-match/LICENSE.md
new file mode 100644
index 0000000..2cdc8e4
--- /dev/null
+++ b/server/node_modules/balanced-match/LICENSE.md
@@ -0,0 +1,21 @@
+(MIT)
+
+Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/balanced-match/README.md b/server/node_modules/balanced-match/README.md
new file mode 100644
index 0000000..d2a48b6
--- /dev/null
+++ b/server/node_modules/balanced-match/README.md
@@ -0,0 +1,97 @@
+# balanced-match
+
+Match balanced string pairs, like `{` and `}` or `<b>` and `</b>`. Supports regular expressions as well!
+
+[![build status](https://secure.travis-ci.org/juliangruber/balanced-match.svg)](http://travis-ci.org/juliangruber/balanced-match)
+[![downloads](https://img.shields.io/npm/dm/balanced-match.svg)](https://www.npmjs.org/package/balanced-match)
+
+[![testling badge](https://ci.testling.com/juliangruber/balanced-match.png)](https://ci.testling.com/juliangruber/balanced-match)
+
+## Example
+
+Get the first matching pair of braces:
+
+```js
+var balanced = require('balanced-match');
+
+console.log(balanced('{', '}', 'pre{in{nested}}post'));
+console.log(balanced('{', '}', 'pre{first}between{second}post'));
+console.log(balanced(/\s+\{\s+/, /\s+\}\s+/, 'pre  {   in{nest}   }  post'));
+```
+
+The matches are:
+
+```bash
+$ node example.js
+{ start: 3, end: 14, pre: 'pre', body: 'in{nested}', post: 'post' }
+{ start: 3,
+  end: 9,
+  pre: 'pre',
+  body: 'first',
+  post: 'between{second}post' }
+{ start: 3, end: 17, pre: 'pre', body: 'in{nest}', post: 'post' }
+```
+
+## API
+
+### var m = balanced(a, b, str)
+
+For the first non-nested matching pair of `a` and `b` in `str`, return an
+object with those keys:
+
+* **start** the index of the first match of `a`
+* **end** the index of the matching `b`
+* **pre** the preamble, `a` and `b` not included
+* **body** the match, `a` and `b` not included
+* **post** the postscript, `a` and `b` not included
+
+If there's no match, `undefined` will be returned.
+
+If the `str` contains more `a` than `b` / there are unmatched pairs, the first match that was closed will be used. For example, `{{a}` will match `['{', 'a', '']` and `{a}}` will match `['', 'a', '}']`.
+
+### var r = balanced.range(a, b, str)
+
+For the first non-nested matching pair of `a` and `b` in `str`, return an
+array with indexes: `[ <a index>, <b index> ]`.
+
+If there's no match, `undefined` will be returned.
+
+If the `str` contains more `a` than `b` / there are unmatched pairs, the first match that was closed will be used. For example, `{{a}` will match `[ 1, 3 ]` and `{a}}` will match `[0, 2]`.
+
+## Installation
+
+With [npm](https://npmjs.org) do:
+
+```bash
+npm install balanced-match
+```
+
+## Security contact information
+
+To report a security vulnerability, please use the
+[Tidelift security contact](https://tidelift.com/security).
+Tidelift will coordinate the fix and disclosure.
+
+## License
+
+(MIT)
+
+Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/balanced-match/index.js b/server/node_modules/balanced-match/index.js
new file mode 100644
index 0000000..c67a646
--- /dev/null
+++ b/server/node_modules/balanced-match/index.js
@@ -0,0 +1,62 @@
+'use strict';
+module.exports = balanced;
+function balanced(a, b, str) {
+  if (a instanceof RegExp) a = maybeMatch(a, str);
+  if (b instanceof RegExp) b = maybeMatch(b, str);
+
+  var r = range(a, b, str);
+
+  return r && {
+    start: r[0],
+    end: r[1],
+    pre: str.slice(0, r[0]),
+    body: str.slice(r[0] + a.length, r[1]),
+    post: str.slice(r[1] + b.length)
+  };
+}
+
+function maybeMatch(reg, str) {
+  var m = str.match(reg);
+  return m ? m[0] : null;
+}
+
+balanced.range = range;
+function range(a, b, str) {
+  var begs, beg, left, right, result;
+  var ai = str.indexOf(a);
+  var bi = str.indexOf(b, ai + 1);
+  var i = ai;
+
+  if (ai >= 0 && bi > 0) {
+    if(a===b) {
+      return [ai, bi];
+    }
+    begs = [];
+    left = str.length;
+
+    while (i >= 0 && !result) {
+      if (i == ai) {
+        begs.push(i);
+        ai = str.indexOf(a, i + 1);
+      } else if (begs.length == 1) {
+        result = [ begs.pop(), bi ];
+      } else {
+        beg = begs.pop();
+        if (beg < left) {
+          left = beg;
+          right = bi;
+        }
+
+        bi = str.indexOf(b, i + 1);
+      }
+
+      i = ai < bi && ai >= 0 ? ai : bi;
+    }
+
+    if (begs.length) {
+      result = [ left, right ];
+    }
+  }
+
+  return result;
+}
diff --git a/server/node_modules/balanced-match/package.json b/server/node_modules/balanced-match/package.json
new file mode 100644
index 0000000..ce6073e
--- /dev/null
+++ b/server/node_modules/balanced-match/package.json
@@ -0,0 +1,48 @@
+{
+  "name": "balanced-match",
+  "description": "Match balanced character pairs, like \"{\" and \"}\"",
+  "version": "1.0.2",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/juliangruber/balanced-match.git"
+  },
+  "homepage": "https://github.com/juliangruber/balanced-match",
+  "main": "index.js",
+  "scripts": {
+    "test": "tape test/test.js",
+    "bench": "matcha test/bench.js"
+  },
+  "devDependencies": {
+    "matcha": "^0.7.0",
+    "tape": "^4.6.0"
+  },
+  "keywords": [
+    "match",
+    "regexp",
+    "test",
+    "balanced",
+    "parse"
+  ],
+  "author": {
+    "name": "Julian Gruber",
+    "email": "mail@juliangruber.com",
+    "url": "http://juliangruber.com"
+  },
+  "license": "MIT",
+  "testling": {
+    "files": "test/*.js",
+    "browsers": [
+      "ie/8..latest",
+      "firefox/20..latest",
+      "firefox/nightly",
+      "chrome/25..latest",
+      "chrome/canary",
+      "opera/12..latest",
+      "opera/next",
+      "safari/5.1..latest",
+      "ipad/6.0..latest",
+      "iphone/6.0..latest",
+      "android-browser/4.2..latest"
+    ]
+  }
+}
diff --git a/server/node_modules/base64-js/LICENSE b/server/node_modules/base64-js/LICENSE
new file mode 100644
index 0000000..6d52b8a
--- /dev/null
+++ b/server/node_modules/base64-js/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Jameson Little
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/base64-js/README.md b/server/node_modules/base64-js/README.md
new file mode 100644
index 0000000..b42a48f
--- /dev/null
+++ b/server/node_modules/base64-js/README.md
@@ -0,0 +1,34 @@
+base64-js
+=========
+
+`base64-js` does basic base64 encoding/decoding in pure JS.
+
+[![build status](https://secure.travis-ci.org/beatgammit/base64-js.png)](http://travis-ci.org/beatgammit/base64-js)
+
+Many browsers already have base64 encoding/decoding functionality, but it is for text data, not all-purpose binary data.
+
+Sometimes encoding/decoding binary data in the browser is useful, and that is what this module does.
+
+## install
+
+With [npm](https://npmjs.org) do:
+
+`npm install base64-js` and `var base64js = require('base64-js')`
+
+For use in web browsers do:
+
+`<script src="base64js.min.js"></script>`
+
+[Get supported base64-js with the Tidelift Subscription](https://tidelift.com/subscription/pkg/npm-base64-js?utm_source=npm-base64-js&utm_medium=referral&utm_campaign=readme)
+
+## methods
+
+`base64js` has three exposed functions, `byteLength`, `toByteArray` and `fromByteArray`, which both take a single argument.
+
+* `byteLength` - Takes a base64 string and returns length of byte array
+* `toByteArray` - Takes a base64 string and returns a byte array
+* `fromByteArray` - Takes a byte array and returns a base64 string
+
+## license
+
+MIT
diff --git a/server/node_modules/base64-js/base64js.min.js b/server/node_modules/base64-js/base64js.min.js
new file mode 100644
index 0000000..908ac83
--- /dev/null
+++ b/server/node_modules/base64-js/base64js.min.js
@@ -0,0 +1 @@
+(function(a){if("object"==typeof exports&&"undefined"!=typeof module)module.exports=a();else if("function"==typeof define&&define.amd)define([],a);else{var b;b="undefined"==typeof window?"undefined"==typeof global?"undefined"==typeof self?this:self:global:window,b.base64js=a()}})(function(){return function(){function b(d,e,g){function a(j,i){if(!e[j]){if(!d[j]){var f="function"==typeof require&&require;if(!i&&f)return f(j,!0);if(h)return h(j,!0);var c=new Error("Cannot find module '"+j+"'");throw c.code="MODULE_NOT_FOUND",c}var k=e[j]={exports:{}};d[j][0].call(k.exports,function(b){var c=d[j][1][b];return a(c||b)},k,k.exports,b,d,e,g)}return e[j].exports}for(var h="function"==typeof require&&require,c=0;c<g.length;c++)a(g[c]);return a}return b}()({"/":[function(a,b,c){'use strict';function d(a){var b=a.length;if(0<b%4)throw new Error("Invalid string. Length must be a multiple of 4");var c=a.indexOf("=");-1===c&&(c=b);var d=c===b?0:4-c%4;return[c,d]}function e(a,b,c){return 3*(b+c)/4-c}function f(a){var b,c,f=d(a),g=f[0],h=f[1],j=new m(e(a,g,h)),k=0,n=0<h?g-4:g;for(c=0;c<n;c+=4)b=l[a.charCodeAt(c)]<<18|l[a.charCodeAt(c+1)]<<12|l[a.charCodeAt(c+2)]<<6|l[a.charCodeAt(c+3)],j[k++]=255&b>>16,j[k++]=255&b>>8,j[k++]=255&b;return 2===h&&(b=l[a.charCodeAt(c)]<<2|l[a.charCodeAt(c+1)]>>4,j[k++]=255&b),1===h&&(b=l[a.charCodeAt(c)]<<10|l[a.charCodeAt(c+1)]<<4|l[a.charCodeAt(c+2)]>>2,j[k++]=255&b>>8,j[k++]=255&b),j}function g(a){return k[63&a>>18]+k[63&a>>12]+k[63&a>>6]+k[63&a]}function h(a,b,c){for(var d,e=[],f=b;f<c;f+=3)d=(16711680&a[f]<<16)+(65280&a[f+1]<<8)+(255&a[f+2]),e.push(g(d));return e.join("")}function j(a){for(var b,c=a.length,d=c%3,e=[],f=16383,g=0,j=c-d;g<j;g+=f)e.push(h(a,g,g+f>j?j:g+f));return 1===d?(b=a[c-1],e.push(k[b>>2]+k[63&b<<4]+"==")):2===d&&(b=(a[c-2]<<8)+a[c-1],e.push(k[b>>10]+k[63&b>>4]+k[63&b<<2]+"=")),e.join("")}c.byteLength=function(a){var b=d(a),c=b[0],e=b[1];return 3*(c+e)/4-e},c.toByteArray=f,c.fromByteArray=j;for(var k=[],l=[],m="undefined"==typeof Uint8Array?Array:Uint8Array,n="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",o=0,p=n.length;o<p;++o)k[o]=n[o],l[n.charCodeAt(o)]=o;l[45]=62,l[95]=63},{}]},{},[])("/")});
\ No newline at end of file
diff --git a/server/node_modules/base64-js/index.d.ts b/server/node_modules/base64-js/index.d.ts
new file mode 100644
index 0000000..7d9fa1d
--- /dev/null
+++ b/server/node_modules/base64-js/index.d.ts
@@ -0,0 +1,3 @@
+export function byteLength(b64: string): number;
+export function toByteArray(b64: string): Uint8Array;
+export function fromByteArray(uint8: Uint8Array): string;
diff --git a/server/node_modules/base64-js/index.js b/server/node_modules/base64-js/index.js
new file mode 100644
index 0000000..0599f3e
--- /dev/null
+++ b/server/node_modules/base64-js/index.js
@@ -0,0 +1,150 @@
+'use strict'
+
+exports.byteLength = byteLength
+exports.toByteArray = toByteArray
+exports.fromByteArray = fromByteArray
+
+var lookup = []
+var revLookup = []
+var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array
+
+var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
+for (var i = 0, len = code.length; i < len; ++i) {
+  lookup[i] = code[i]
+  revLookup[code.charCodeAt(i)] = i
+}
+
+// Support decoding URL-safe base64 strings, as Node.js does.
+// See: https://en.wikipedia.org/wiki/Base64#URL_applications
+revLookup['-'.charCodeAt(0)] = 62
+revLookup['_'.charCodeAt(0)] = 63
+
+function getLens (b64) {
+  var len = b64.length
+
+  if (len % 4 > 0) {
+    throw new Error('Invalid string. Length must be a multiple of 4')
+  }
+
+  // Trim off extra bytes after placeholder bytes are found
+  // See: https://github.com/beatgammit/base64-js/issues/42
+  var validLen = b64.indexOf('=')
+  if (validLen === -1) validLen = len
+
+  var placeHoldersLen = validLen === len
+    ? 0
+    : 4 - (validLen % 4)
+
+  return [validLen, placeHoldersLen]
+}
+
+// base64 is 4/3 + up to two characters of the original data
+function byteLength (b64) {
+  var lens = getLens(b64)
+  var validLen = lens[0]
+  var placeHoldersLen = lens[1]
+  return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
+}
+
+function _byteLength (b64, validLen, placeHoldersLen) {
+  return ((validLen + placeHoldersLen) * 3 / 4) - placeHoldersLen
+}
+
+function toByteArray (b64) {
+  var tmp
+  var lens = getLens(b64)
+  var validLen = lens[0]
+  var placeHoldersLen = lens[1]
+
+  var arr = new Arr(_byteLength(b64, validLen, placeHoldersLen))
+
+  var curByte = 0
+
+  // if there are placeholders, only get up to the last complete 4 chars
+  var len = placeHoldersLen > 0
+    ? validLen - 4
+    : validLen
+
+  var i
+  for (i = 0; i < len; i += 4) {
+    tmp =
+      (revLookup[b64.charCodeAt(i)] << 18) |
+      (revLookup[b64.charCodeAt(i + 1)] << 12) |
+      (revLookup[b64.charCodeAt(i + 2)] << 6) |
+      revLookup[b64.charCodeAt(i + 3)]
+    arr[curByte++] = (tmp >> 16) & 0xFF
+    arr[curByte++] = (tmp >> 8) & 0xFF
+    arr[curByte++] = tmp & 0xFF
+  }
+
+  if (placeHoldersLen === 2) {
+    tmp =
+      (revLookup[b64.charCodeAt(i)] << 2) |
+      (revLookup[b64.charCodeAt(i + 1)] >> 4)
+    arr[curByte++] = tmp & 0xFF
+  }
+
+  if (placeHoldersLen === 1) {
+    tmp =
+      (revLookup[b64.charCodeAt(i)] << 10) |
+      (revLookup[b64.charCodeAt(i + 1)] << 4) |
+      (revLookup[b64.charCodeAt(i + 2)] >> 2)
+    arr[curByte++] = (tmp >> 8) & 0xFF
+    arr[curByte++] = tmp & 0xFF
+  }
+
+  return arr
+}
+
+function tripletToBase64 (num) {
+  return lookup[num >> 18 & 0x3F] +
+    lookup[num >> 12 & 0x3F] +
+    lookup[num >> 6 & 0x3F] +
+    lookup[num & 0x3F]
+}
+
+function encodeChunk (uint8, start, end) {
+  var tmp
+  var output = []
+  for (var i = start; i < end; i += 3) {
+    tmp =
+      ((uint8[i] << 16) & 0xFF0000) +
+      ((uint8[i + 1] << 8) & 0xFF00) +
+      (uint8[i + 2] & 0xFF)
+    output.push(tripletToBase64(tmp))
+  }
+  return output.join('')
+}
+
+function fromByteArray (uint8) {
+  var tmp
+  var len = uint8.length
+  var extraBytes = len % 3 // if we have 1 byte left, pad 2 bytes
+  var parts = []
+  var maxChunkLength = 16383 // must be multiple of 3
+
+  // go through the array every three bytes, we'll deal with trailing stuff later
+  for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
+    parts.push(encodeChunk(uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)))
+  }
+
+  // pad the end with zeros, but make sure to not forget the extra bytes
+  if (extraBytes === 1) {
+    tmp = uint8[len - 1]
+    parts.push(
+      lookup[tmp >> 2] +
+      lookup[(tmp << 4) & 0x3F] +
+      '=='
+    )
+  } else if (extraBytes === 2) {
+    tmp = (uint8[len - 2] << 8) + uint8[len - 1]
+    parts.push(
+      lookup[tmp >> 10] +
+      lookup[(tmp >> 4) & 0x3F] +
+      lookup[(tmp << 2) & 0x3F] +
+      '='
+    )
+  }
+
+  return parts.join('')
+}
diff --git a/server/node_modules/base64-js/package.json b/server/node_modules/base64-js/package.json
new file mode 100644
index 0000000..c3972e3
--- /dev/null
+++ b/server/node_modules/base64-js/package.json
@@ -0,0 +1,47 @@
+{
+  "name": "base64-js",
+  "description": "Base64 encoding/decoding in pure JS",
+  "version": "1.5.1",
+  "author": "T. Jameson Little <t.jameson.little@gmail.com>",
+  "typings": "index.d.ts",
+  "bugs": {
+    "url": "https://github.com/beatgammit/base64-js/issues"
+  },
+  "devDependencies": {
+    "babel-minify": "^0.5.1",
+    "benchmark": "^2.1.4",
+    "browserify": "^16.3.0",
+    "standard": "*",
+    "tape": "4.x"
+  },
+  "homepage": "https://github.com/beatgammit/base64-js",
+  "keywords": [
+    "base64"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/beatgammit/base64-js.git"
+  },
+  "scripts": {
+    "build": "browserify -s base64js -r ./ | minify > base64js.min.js",
+    "lint": "standard",
+    "test": "npm run lint && npm run unit",
+    "unit": "tape test/*.js"
+  },
+  "funding": [
+    {
+      "type": "github",
+      "url": "https://github.com/sponsors/feross"
+    },
+    {
+      "type": "patreon",
+      "url": "https://www.patreon.com/feross"
+    },
+    {
+      "type": "consulting",
+      "url": "https://feross.org/support"
+    }
+  ]
+}
diff --git a/server/node_modules/bcrypt/.dockerignore b/server/node_modules/bcrypt/.dockerignore
new file mode 100644
index 0000000..01f4eb7
--- /dev/null
+++ b/server/node_modules/bcrypt/.dockerignore
@@ -0,0 +1,6 @@
+.git/
+.vscode/
+Dockerfile*
+prebuilds/
+node_modules/
+build*/
diff --git a/server/node_modules/bcrypt/.editorconfig b/server/node_modules/bcrypt/.editorconfig
new file mode 100644
index 0000000..4e12f93
--- /dev/null
+++ b/server/node_modules/bcrypt/.editorconfig
@@ -0,0 +1,19 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[{package.json,*.yml}]
+indent_style = space
+indent_size = 2
+
+[appveyor.yml]
+end_of_line = crlf
+
+[*.md]
+trim_trailing_whitespace = false
diff --git a/server/node_modules/bcrypt/.github/workflows/build-pack-publish.yml b/server/node_modules/bcrypt/.github/workflows/build-pack-publish.yml
new file mode 100644
index 0000000..9b14ee1
--- /dev/null
+++ b/server/node_modules/bcrypt/.github/workflows/build-pack-publish.yml
@@ -0,0 +1,110 @@
+name: Prebuildify, package, publish
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+  release:
+    types: [ prereleased, released ]
+
+jobs:
+  build-linux:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      # This is unsafe, but we really don't use any other native dependencies
+      - run: npm ci
+      - run: docker run -u $(id -u):$(id -g) -v `pwd`:/input -w /input ghcr.io/prebuild/almalinux-devtoolset11 npx prebuildify --napi --tag-libc --strip --target=node@18.0.0
+      - run: docker run -u $(id -u):$(id -g) -v `pwd`:/input -w /input ghcr.io/prebuild/alpine npx prebuildify --napi --tag-libc --strip --target=node@18.0.0
+      - run: docker run -u $(id -u):$(id -g) -v `pwd`:/input -w /input ghcr.io/prebuild/linux-armv7 npx prebuildify --napi --tag-libc --strip --target=node@18.0.0
+      - run: docker run -u $(id -u):$(id -g) -v `pwd`:/input -w /input ghcr.io/prebuild/linux-armv7l-musl npx prebuildify --napi --tag-libc --strip --target=node@18.0.0
+      - run: docker run -u $(id -u):$(id -g) -v `pwd`:/input -w /input ghcr.io/prebuild/linux-arm64 npx prebuildify --napi --tag-libc --strip --target=node@18.0.0
+      - run: docker run -u $(id -u):$(id -g) -v `pwd`:/input -w /input ghcr.io/prebuild/linux-arm64-musl npx prebuildify --napi --tag-libc --strip --target=node@18.0.0
+      - run: find prebuilds
+      - uses: actions/upload-artifact@v4
+        with:
+          name: prebuild-linux
+          path: ./prebuilds/
+
+  build-windows:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          registry-url: 'https://registry.npmjs.org'
+      - run: npm ci
+      - run: npx prebuildify --napi --strip --arch=x64 --target=node@18.0.0
+      - run: npx prebuildify --napi --strip --arch=arm64 --target=node@20.0.0
+      - run: dir prebuilds
+      - uses: actions/upload-artifact@v4
+        with:
+          name: prebuild-windows
+          path: ./prebuilds/
+
+  build-macos:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18
+          registry-url: 'https://registry.npmjs.org'
+      - run: npm ci
+      - run: npx prebuildify --napi --strip --arch=arm64 --target=node@18.0.0
+      - run: npx prebuildify --napi --strip --arch=x64 --target=node@18.0.0
+      - run: find prebuilds
+      - uses: actions/upload-artifact@v4
+        with:
+          name: prebuild-macos
+          path: ./prebuilds/
+
+  pack:
+    needs:
+      - build-linux
+      - build-windows
+      - build-macos
+    runs-on: ubuntu-latest
+    outputs:
+        PACK_FILE: ${{ steps.pack.outputs.PACK_FILE }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/download-artifact@v4
+        with:
+          path: /tmp/prebuilds/
+      - name: Coalesce prebuilds from build matrix
+        run: |
+          mkdir prebuilds
+          for d in /tmp/prebuilds/*; do
+            cp -Rav $d/* prebuilds/
+          done
+      - run: chmod a+x prebuilds/*/*.node && find prebuilds -executable -type f
+      - id: pack
+        name: Prepare NPM package
+        run: |
+          echo "PACK_FILE=$(npm pack)" >> "$GITHUB_OUTPUT"
+      - uses: actions/upload-artifact@v4
+        with:
+          name: package-tgz
+          path: ${{ steps.pack.outputs.PACK_FILE }}
+          if-no-files-found: 'error'
+
+  test-package:
+    needs: pack
+    strategy:
+      matrix:
+        node-version: [ 18, 20, 22, 23 ]
+        os: [ ubuntu-latest, windows-latest, macos-latest ]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          registry-url: 'https://registry.npmjs.org'
+      - uses: actions/download-artifact@v4
+        with:
+          name: package-tgz
+      - run: npm install ${{ needs.pack.outputs.PACK_FILE }}
+      - run: node -e "const b = require('bcrypt'); const h = b.hashSync('hello', 10); console.log(h, b.compareSync('hello', h))"
diff --git a/server/node_modules/bcrypt/.github/workflows/ci.yaml b/server/node_modules/bcrypt/.github/workflows/ci.yaml
new file mode 100644
index 0000000..77c4e5a
--- /dev/null
+++ b/server/node_modules/bcrypt/.github/workflows/ci.yaml
@@ -0,0 +1,42 @@
+name: ci
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [18, 20, 22]
+    steps:
+      - uses: actions/checkout@v4
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+      - run: npm ci
+      - name: Test
+        run: npm test
+
+  build-alpine:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [18, 20, 22]
+    container:
+      image: node:${{ matrix.node-version }}-alpine
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install dependencies
+        run: |
+          apk add make g++ python3
+      - run: npm ci
+      - name: Test
+        run: |
+          npm test --unsafe-perm
diff --git a/server/node_modules/bcrypt/CHANGELOG.md b/server/node_modules/bcrypt/CHANGELOG.md
new file mode 100644
index 0000000..eab713b
--- /dev/null
+++ b/server/node_modules/bcrypt/CHANGELOG.md
@@ -0,0 +1,184 @@
+# 6.0.0 (2025-02-28)
+  * Drop support for NodeJS <= 16
+  * Remove `node-pre-gyp` in favor of `prebuildify`, prebuilt binaries are now shipped with the package
+  * Update `node-addon-api` to 8.3.0
+  * Update JS code to newer ES syntax
+
+# 5.1.0 (2022-10-06)
+  * Update `node-pre-gyp` to 1.0.11
+
+# 5.1.0 (2022-10-06)
+  * Update `node-pre-gyp` to 1.0.10
+  * Replace `nodeunit` with `jest` as the testing library
+
+# 5.0.1 (2021-02-22)
+
+  * Update `node-pre-gyp` to 1.0.0
+
+# 5.0.0 (2020-06-02)
+
+  * Fix the bcrypt "wrap-around" bug. It affects passwords with lengths >= 255.
+    It is uncommon but it's a bug nevertheless. Previous attempts to fix the bug
+    was unsuccessful.
+  * Experimental support for z/OS
+  * Fix a bug related to NUL in password input
+  * Update `node-pre-gyp` to 0.15.0
+
+# 4.0.1 (2020-02-27)
+
+  * Fix compilation errors in Alpine linux
+
+# 4.0.0 (2020-02-17)
+
+  * Switch to NAPI bcrypt
+  * Drop support for NodeJS 8
+
+# 3.0.8 (2019-12-31)
+
+  * Update `node-pre-gyp` to 0.14
+  * Pre-built binaries for NodeJS 13
+
+# 3.0.7 (2019-10-18)
+
+  * Update `nan` to 2.14.0
+  * Update `node-pre-gyp` to 0.13
+
+# 3.0.6 (2019-04-11)
+
+  * Update `nan` to 2.13.2
+
+# 3.0.5 (2019-03-19)
+
+  * Update `nan` to 2.13.1
+  * NodeJS 12 compatibility
+  * Remove `node-pre-gyp` from bundled dependencies
+
+# 3.0.4-napi (2019-03-08)
+
+  * Sync N-API bcrypt with NAN bcrypt
+
+# 3.0.4 (2019-02-07)
+
+  * Fix GCC, NAN and V8 deprecation warnings
+
+# 3.0.3 (2018-12-19)
+
+  * Update `nan` to 2.12.1
+
+# 3.0.2 (2018-10-18)
+
+  * Update `nan` to 2.11.1
+
+# 3.0.1 (2018-09-20)
+
+  * Update `nan` to 2.11.0
+
+# 3.0.0 (2018-07-06)
+
+  * Drop support for NodeJS <= 4
+
+# 2.0.1 (2018-04-20)
+
+  * Update `node-pre-gyp` to allow downloading prebuilt modules
+
+# 2.0.0 (2018-04-07)
+
+  * Make `2b` the default bcrypt version
+
+# 1.1.0-napi (2018-01-21)
+
+  * Initial support for [N-API](https://nodejs.org/api/n-api.html)
+
+# 1.0.3 (2016-08-23)
+
+  * update to nan v2.6.2 for NodeJS 8 support
+  * Fix: use npm scripts instead of node-gyp directly.
+
+# 1.0.2 (2016-12-31)
+
+  * Fix `compare` promise rejection with invalid arguments
+
+# 1.0.1 (2016-12-07)
+
+  * Fix destructuring imports with promises
+
+# 1.0.0 (2016-12-04)
+
+  * add Promise support (commit 2488473)
+
+# 0.8.7 (2016-06-09)
+
+  * update nan to 2.3.5 for improved node v6 support
+
+# 0.8.6 (2016-04-20)
+
+  * update nan for node v6 support
+
+# 0.8.5 (2015-08-12)
+
+  * update to nan v2 (adds support for iojs 3)
+
+# 0.8.4 (2015-07-24)
+
+  * fix deprecation warning for the Encode API
+
+# 0.8.3 (2015-05-06)
+
+  * update nan to 1.8.4 for iojs 2.x support
+
+# 0.8.2 (2015-03-28)
+
+  * always use callback for generating random bytes to avoid blocking
+
+# 0.8.1 (2015-01-18)
+  * update NaN to 1.5.0 for iojs support
+
+# 0.8.0 (2014-08-03)
+  * migrate to NAN for bindings
+
+# v0.5.0
+  * Fix for issue around empty string params throwing Errors.
+  * Method deprecation.
+  * Upgrade from libeio/ev to libuv. (shtylman)
+  ** --- NOTE --- Breaks 0.4.x compatability
+  * EV_MULTIPLICITY compile flag.
+
+# v0.4.1
+  * Thread safety fix around OpenSSL (GH-32). (bnoordhuis - through node)
+  * C++ code changes using delete and new instead of malloc and free. (shtylman)
+  * Compile options for speed, zoom. (shtylman)
+  * Move much of the type and variable checking to the JS. (shtylman)
+
+# v0.4.0
+  * Added getRounds function that will tell you the number of rounds within a hash/salt
+
+# v0.3.2
+  * Fix api issue with async salt gen first param
+
+# v0.3.1
+  * Compile under node 0.5.x
+
+# v0.3.0
+  * Internal Refactoring
+  * Remove pthread dependencies and locking
+  * Fix compiler warnings and a memory bug
+
+# v0.2.4
+  * Use threadsafe functions instead of pthread mutexes
+  * salt validation to make sure the salt is of the correct size and format
+
+# v0.2.3
+  * cygwin support
+
+# v0.2.2
+  * Remove dependency on libbsd, use libssl instead
+
+# v0.2.0
+  * Added async functionality
+  * API changes
+    * hashpw -> encrypt
+    * all old sync methods now end with _sync
+  * Removed libbsd(arc4random) dependency...now uses openssl which is more widely spread
+
+# v0.1.2
+  * Security fix. Wasn't reading rounds in properly and was always only using 4 rounds
diff --git a/server/node_modules/bcrypt/Dockerfile b/server/node_modules/bcrypt/Dockerfile
new file mode 100755
index 0000000..2802baf
--- /dev/null
+++ b/server/node_modules/bcrypt/Dockerfile
@@ -0,0 +1,57 @@
+# Usage:
+#
+#   docker build -t bcryptjs-builder .
+#   CONTAINER=$(docker create bcryptjs-builder)
+#   # Then copy the artifact to your host:
+#   docker cp "$CONTAINER:/usr/local/opt/bcrypt-js/prebuilds" .
+#   docker rm "$CONTAINER"
+#
+# Use --platform to build cross-platform i.e. for ARM:
+#
+#   docker build -t bcryptjs-builder --platform "linux/arm64/v8" .
+#   CONTAINER=$docker create --platform "linux/arm64/v8" bcryptjs-builder)
+#   # this copies the prebuilds/linux-arm artifacts
+#   docker cp "$CONTAINER:/usr/local/opt/bcrypt-js/prebuilds" .
+#   docker rm "$CONTAINER"
+
+
+ARG FROM_IMAGE=node:18-bullseye
+#ARG FROM_IMAGE=arm32v7/node:16-bullseye
+#ARG FROM_IMAGE=arm64v8/node:16-bullseye
+FROM ${FROM_IMAGE}
+
+ENV project bcrypt-js
+ENV DEBIAN_FRONTEND noninteractive
+ENV LC_ALL en_US.UTF-8
+ENV LANG ${LC_ALL}
+
+RUN echo "#log: ${project}: Setup system" \
+  && set -x \
+  && apt-get update -y \
+  && apt-get install -y \
+    build-essential \
+    python3 \
+  && apt-get clean \
+  && update-alternatives --install /usr/local/bin/python python /usr/bin/python3 20 \
+  && npm i -g prebuildify@5 node-gyp@9 \
+  && sync
+
+ADD . /usr/local/opt/${project}
+WORKDIR /usr/local/opt/${project}
+
+RUN echo "#log: ${project}: Running build" \
+  && set -x \
+  && npm ci \
+  && npm run build
+
+ARG RUN_TESTS=true
+ARG TEST_TIMEOUT_SECONDS=
+
+RUN if "${RUN_TESTS}"; then \
+    echo "#log ${project}: Running tests" \
+    && npm test; \
+  else \
+    echo "#log ${project}: Tests were skipped!"; \
+  fi
+
+CMD /bin/bash -l
diff --git a/server/node_modules/bcrypt/Dockerfile-alpine b/server/node_modules/bcrypt/Dockerfile-alpine
new file mode 100755
index 0000000..7570cfe
--- /dev/null
+++ b/server/node_modules/bcrypt/Dockerfile-alpine
@@ -0,0 +1,41 @@
+# Usage:
+#
+#   docker build -t bcryptjs-linux-alpine-builder -f Dockerfile-alpine .
+#   CONTAINER=$(docker create bcryptjs-linux-alpine-builder)
+#   # Then copy the artifact to your host:
+#   docker cp "$CONTAINER:/usr/local/opt/bcrypt-js/prebuilds" .
+#   docker rm "$CONTAINER"
+
+ARG FROM_IMAGE=node:18-alpine
+FROM ${FROM_IMAGE}
+
+ENV project bcrypt-js
+ENV DEBIAN_FRONTEND noninteractive
+ENV LC_ALL en_US.UTF-8
+ENV LANG ${LC_ALL}
+
+RUN echo "#log: ${project}: Setup system" \
+  && set -x \
+  && apk add --update build-base python3 \
+  && npm i -g prebuildify@5 node-gyp@9 \
+  && sync
+
+ADD . /usr/local/opt/${project}
+WORKDIR /usr/local/opt/${project}
+
+RUN echo "#log: ${project}: Running build" \
+  && set -x \
+  && npm ci \
+  && npm run build
+
+ARG RUN_TESTS=true
+ARG TEST_TIMEOUT_SECONDS=
+
+RUN if "${RUN_TESTS}"; then \
+    echo "#log ${project}: Running tests" \
+    && npm test; \
+  else \
+    echo "#log ${project}: Tests were skipped!"; \
+  fi
+
+CMD /bin/bash -l
diff --git a/server/node_modules/bcrypt/ISSUE_TEMPLATE.md b/server/node_modules/bcrypt/ISSUE_TEMPLATE.md
new file mode 100644
index 0000000..b4baa00
--- /dev/null
+++ b/server/node_modules/bcrypt/ISSUE_TEMPLATE.md
@@ -0,0 +1,18 @@
+Thanks for reporting a new issue with the node bcrypt module!
+
+To help you resolve your issue faster please make sure you have done the following:
+
+* Searched existing issues (even closed ones) for your same problem
+* Make sure you have installed the required dependencies listed on the readme
+* Read your npm error log for lines telling you what failed, usually it is a problem with not having the correct dependencies installed to build the native module
+
+Once you have done the above and are still confident that the issue is with the module, please describe it below. Some things that really help get your issue resolved faster are:
+
+* What went wrong?
+* What did you expect to happen?
+* Which version of nodejs and OS?
+* If you find a bug, please write a failing test.
+
+Thanks!
+
+P.S. If it doesn't look like you read the above then your issue will likely be closed without further explanation. Sorry, but there are just too many issues opened with no useful information or questions which have been previously addressed.
diff --git a/server/node_modules/bcrypt/LICENSE b/server/node_modules/bcrypt/LICENSE
new file mode 100644
index 0000000..94e2ba5
--- /dev/null
+++ b/server/node_modules/bcrypt/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2010 Nicholas Campbell
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/bcrypt/Makefile b/server/node_modules/bcrypt/Makefile
new file mode 100644
index 0000000..cb22252
--- /dev/null
+++ b/server/node_modules/bcrypt/Makefile
@@ -0,0 +1,19 @@
+TESTS = test/*.js
+
+all: test
+
+build: clean compile
+
+compile:
+	npm install .
+	npm run install
+
+test: build
+	@./node_modules/.bin/jest \
+		$(TESTS)
+
+clean:
+	rm -Rf lib/bindings/
+
+
+.PHONY: clean test build
diff --git a/server/node_modules/bcrypt/README.md b/server/node_modules/bcrypt/README.md
new file mode 100644
index 0000000..e923108
--- /dev/null
+++ b/server/node_modules/bcrypt/README.md
@@ -0,0 +1,388 @@
+# node.bcrypt.js
+
+[![ci](https://github.com/kelektiv/node.bcrypt.js/actions/workflows/ci.yaml/badge.svg)](https://github.com/kelektiv/node.bcrypt.js/actions/workflows/ci.yaml)
+
+[![Build Status](https://ci.appveyor.com/api/projects/status/github/kelektiv/node.bcrypt.js)](https://ci.appveyor.com/project/defunctzombie/node-bcrypt-js-pgo26/branch/master)
+
+A library to help you hash passwords.
+
+You can read about [bcrypt in Wikipedia][bcryptwiki] as well as in the following article:
+[How To Safely Store A Password][codahale]
+
+## If You Are Submitting Bugs or Issues
+
+Please verify that the NodeJS version you are using is a _stable_ version; Unstable versions are currently not supported and issues created while using an unstable version will be closed.
+
+If you are on a stable version of NodeJS, please provide a sufficient code snippet or log files for installation issues. The code snippet does not require you to include confidential information. However, it must provide enough information so the problem can be replicable, or it may be closed without an explanation.
+
+
+## Version Compatibility
+
+_Please upgrade to atleast v5.0.0 to avoid security issues mentioned below._
+
+| Node Version   |   Bcrypt Version  |
+| -------------- | ------------------|
+| 0.4            | <= 0.4            |
+| 0.6, 0.8, 0.10 | >= 0.5            |
+| 0.11           | >= 0.8            |
+| 4              | <= 2.1.0          |
+| 8              | >= 1.0.3 < 4.0.0  |
+| 10, 11         | >= 3              |
+| 12 onwards     | >= 3.0.6          |
+
+`node-gyp` only works with stable/released versions of node. Since the `bcrypt` module uses `node-gyp` to build and install, you'll need a stable version of node to use bcrypt. If you do not, you'll likely see an error that starts with:
+
+```
+gyp ERR! stack Error: "pre" versions of node cannot be installed, use the --nodedir flag instead
+```
+
+## Security Issues And Concerns
+
+> Per bcrypt implementation, only the first 72 bytes of a string are used. Any extra bytes are ignored when matching passwords. Note that this is not the first 72 *characters*. It is possible for a string to contain less than 72 characters, while taking up more than 72 bytes (e.g. a UTF-8 encoded string containing emojis). If a string is provided, it will be encoded using UTF-8.
+
+As should be the case with any security tool, anyone using this library should scrutinise it. If you find or suspect an issue with the code, please bring it to the maintainers' attention. We will spend some time ensuring that this library is as secure as possible.
+
+Here is a list of BCrypt-related security issues/concerns that have come up over the years.
+
+* An [issue with passwords][jtr] was found with a version of the Blowfish algorithm developed for John the Ripper. This is not present in the OpenBSD version and is thus not a problem for this module. HT [zooko][zooko].
+* Versions `< 5.0.0` suffer from bcrypt wrap-around bug and _will truncate passwords >= 255 characters leading to severely weakened passwords_. Please upgrade at  earliest. See [this wiki page][wrap-around-bug] for more details.
+* Versions `< 5.0.0` _do not handle NUL characters inside passwords properly leading to all subsequent characters being dropped and thus resulting in severely weakened passwords_. Please upgrade at earliest. See [this wiki page][improper-nuls] for more details.
+
+## Compatibility Note
+
+This library supports `$2a$` and `$2b$` prefix bcrypt hashes. `$2x$` and `$2y$` hashes are specific to bcrypt implementation developed for John the Ripper. In theory, they should be compatible with `$2b$` prefix.
+
+Compatibility with hashes generated by other languages is not 100% guaranteed due to difference in character encodings. However, it should not be an issue for most cases.
+
+### Migrating from v1.0.x
+
+Hashes generated in earlier version of `bcrypt` remain 100% supported in `v2.x.x` and later versions. In most cases, the migration should be a bump in the `package.json`.
+
+Hashes generated in `v2.x.x` using the defaults parameters will not work in earlier versions.
+
+## Dependencies
+
+* NodeJS
+* `node-gyp`
+ * Please check the dependencies for this tool at: https://github.com/nodejs/node-gyp
+  * Windows users will need the options for c# and c++ installed with their visual studio instance.
+  * Python 2.x/3.x
+* `OpenSSL` - This is only required to build the `bcrypt` project if you are using versions <= 0.7.7. Otherwise, we're using the builtin node crypto bindings for seed data (which use the same OpenSSL code paths we were, but don't have the external dependency).
+
+## Install via NPM
+
+```
+npm install bcrypt
+```
+***Note:*** OS X users using Xcode 4.3.1 or above may need to run the following command in their terminal prior to installing if errors occur regarding xcodebuild: ```sudo xcode-select -switch /Applications/Xcode.app/Contents/Developer```
+
+_Pre-built binaries for various NodeJS versions are made available on a best-effort basis._
+
+Only the current stable and supported LTS releases are actively tested against.
+
+_There may be an interval between the release of the module and the availabilty of the compiled modules._
+
+Currently, we have pre-built binaries that support the following platforms:
+
+1. Windows x32 and x64
+2. Linux x64 (GlibC and musl)
+3. macOS
+
+If you face an error like this:
+
+```
+node-pre-gyp ERR! Tried to download(404): https://github.com/kelektiv/node.bcrypt.js/releases/download/v1.0.2/bcrypt_lib-v1.0.2-node-v48-linux-x64.tar.gz
+```
+
+make sure you have the appropriate dependencies installed and configured for your platform. You can find installation instructions for the dependencies for some common platforms [in this page][depsinstall].
+
+## Usage
+
+### async (recommended)
+
+```javascript
+const bcrypt = require('bcrypt');
+const saltRounds = 10;
+const myPlaintextPassword = 's0/\/\P4$$w0rD';
+const someOtherPlaintextPassword = 'not_bacon';
+```
+
+#### To hash a password:
+
+Technique 1 (generate a salt and hash on separate function calls):
+
+```javascript
+bcrypt.genSalt(saltRounds, function(err, salt) {
+    bcrypt.hash(myPlaintextPassword, salt, function(err, hash) {
+        // Store hash in your password DB.
+    });
+});
+```
+
+Technique 2 (auto-gen a salt and hash):
+
+```javascript
+bcrypt.hash(myPlaintextPassword, saltRounds, function(err, hash) {
+    // Store hash in your password DB.
+});
+```
+
+Note that both techniques achieve the same end-result.
+
+#### To check a password:
+
+```javascript
+// Load hash from your password DB.
+bcrypt.compare(myPlaintextPassword, hash, function(err, result) {
+    // result == true
+});
+bcrypt.compare(someOtherPlaintextPassword, hash, function(err, result) {
+    // result == false
+});
+```
+
+[A Note on Timing Attacks](#a-note-on-timing-attacks)
+
+### with promises
+
+bcrypt uses whatever `Promise` implementation is available in `global.Promise`. NodeJS >= 0.12 has a native `Promise` implementation built in. However, this should work in any Promises/A+ compliant implementation.
+
+Async methods that accept a callback, return a `Promise` when callback is not specified if Promise support is available.
+
+```javascript
+bcrypt.hash(myPlaintextPassword, saltRounds).then(function(hash) {
+    // Store hash in your password DB.
+});
+```
+```javascript
+// Load hash from your password DB.
+bcrypt.compare(myPlaintextPassword, hash).then(function(result) {
+    // result == true
+});
+bcrypt.compare(someOtherPlaintextPassword, hash).then(function(result) {
+    // result == false
+});
+```
+
+This is also compatible with `async/await`
+
+```javascript
+async function checkUser(username, password) {
+    //... fetch user from a db etc.
+
+    const match = await bcrypt.compare(password, user.passwordHash);
+
+    if(match) {
+        //login
+    }
+
+    //...
+}
+```
+
+### ESM import
+```javascript
+import bcrypt from "bcrypt";
+
+// later
+await bcrypt.compare(password, hash);
+```
+
+### sync
+
+```javascript
+const bcrypt = require('bcrypt');
+const saltRounds = 10;
+const myPlaintextPassword = 's0/\/\P4$$w0rD';
+const someOtherPlaintextPassword = 'not_bacon';
+```
+
+#### To hash a password:
+
+Technique 1 (generate a salt and hash on separate function calls):
+
+```javascript
+const salt = bcrypt.genSaltSync(saltRounds);
+const hash = bcrypt.hashSync(myPlaintextPassword, salt);
+// Store hash in your password DB.
+```
+
+Technique 2 (auto-gen a salt and hash):
+
+```javascript
+const hash = bcrypt.hashSync(myPlaintextPassword, saltRounds);
+// Store hash in your password DB.
+```
+
+As with async, both techniques achieve the same end-result.
+
+#### To check a password:
+
+```javascript
+// Load hash from your password DB.
+bcrypt.compareSync(myPlaintextPassword, hash); // true
+bcrypt.compareSync(someOtherPlaintextPassword, hash); // false
+```
+
+[A Note on Timing Attacks](#a-note-on-timing-attacks)
+
+### Why is async mode recommended over sync mode?
+We recommend using async API if you use `bcrypt` on a server. Bcrypt hashing is CPU intensive which will cause the sync APIs to block the event loop and prevent your application from servicing any inbound requests or events. The async version uses a thread pool which does not block the main event loop.
+
+## API
+
+`BCrypt.`
+
+  * `genSaltSync(rounds, minor)`
+    * `rounds` - [OPTIONAL] - the cost of processing the data. (default - 10)
+    * `minor` - [OPTIONAL] - minor version of bcrypt to use. (default - b)
+  * `genSalt(rounds, minor, cb)`
+    * `rounds` - [OPTIONAL] - the cost of processing the data. (default - 10)
+    * `minor` - [OPTIONAL] - minor version of bcrypt to use. (default - b)
+    * `cb` - [OPTIONAL] - a callback to be fired once the salt has been generated. uses eio making it asynchronous. If `cb` is not specified, a `Promise` is returned if Promise support is available.
+      * `err` - First parameter to the callback detailing any errors.
+      * `salt` - Second parameter to the callback providing the generated salt.
+  * `hashSync(data, salt)`
+    * `data` - [REQUIRED] - the data to be encrypted.
+    * `salt` - [REQUIRED] - the salt to be used to hash the password. if specified as a number then a salt will be generated with the specified number of rounds and used (see example under **Usage**).
+  * `hash(data, salt, cb)`
+    * `data` - [REQUIRED] - the data to be encrypted.
+    * `salt` - [REQUIRED] - the salt to be used to hash the password. if specified as a number then a salt will be generated with the specified number of rounds and used (see example under **Usage**).
+    * `cb` - [OPTIONAL] - a callback to be fired once the data has been encrypted. uses eio making it asynchronous. If `cb` is not specified, a `Promise` is returned if Promise support is available.
+      * `err` - First parameter to the callback detailing any errors.
+      * `encrypted` - Second parameter to the callback providing the encrypted form.
+  * `compareSync(data, encrypted)`
+    * `data` - [REQUIRED] - data to compare.
+    * `encrypted` - [REQUIRED] - data to be compared to.
+  * `compare(data, encrypted, cb)`
+    * `data` - [REQUIRED] - data to compare.
+    * `encrypted` - [REQUIRED] - data to be compared to.
+    * `cb` - [OPTIONAL] - a callback to be fired once the data has been compared. uses eio making it asynchronous. If `cb` is not specified, a `Promise` is returned if Promise support is available.
+      * `err` - First parameter to the callback detailing any errors.
+      * `same` - Second parameter to the callback providing whether the data and encrypted forms match [true | false].
+  * `getRounds(encrypted)` - return the number of rounds used to encrypt a given hash
+    * `encrypted` - [REQUIRED] - hash from which the number of rounds used should be extracted.
+
+## A Note on Rounds
+
+A note about the cost: when you are hashing your data, the module will go through a series of rounds to give you a secure hash. The value you submit is not just the number of rounds the module will go through to hash your data. The module will use the value you enter and go through `2^rounds` hashing iterations.
+
+From @garthk, on a 2GHz core you can roughly expect:
+
+    rounds=8 : ~40 hashes/sec
+    rounds=9 : ~20 hashes/sec
+    rounds=10: ~10 hashes/sec
+    rounds=11: ~5  hashes/sec
+    rounds=12: 2-3 hashes/sec
+    rounds=13: ~1 sec/hash
+    rounds=14: ~1.5 sec/hash
+    rounds=15: ~3 sec/hash
+    rounds=25: ~1 hour/hash
+    rounds=31: 2-3 days/hash
+
+
+## A Note on Timing Attacks
+
+Because it's come up multiple times in this project and other bcrypt projects, it needs to be said. The `bcrypt` library is not susceptible to timing attacks. From codahale/bcrypt-ruby#42:
+
+> One of the desired properties of a cryptographic hash function is preimage attack resistance, which means there is no shortcut for generating a message which, when hashed, produces a specific digest.
+
+A great thread on this, in much more detail can be found @ codahale/bcrypt-ruby#43
+
+If you're unfamiliar with timing attacks and want to learn more you can find a great writeup @ [A Lesson In Timing Attacks][timingatk]
+
+However, timing attacks are real. And the comparison function is _not_ time safe. That means that it may exit the function early in the comparison process. Timing attacks happen because of the above. We don't need to be careful that an attacker will learn anything, and our comparison function provides a comparison of hashes. It is a utility to the overall purpose of the library. If you end up using it for something else, we cannot guarantee the security of the comparator. Keep that in mind as you use the library.
+
+## Hash Info
+
+The characters that comprise the resultant hash are `./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789$`.
+
+Resultant hashes will be 60 characters long and they will include the salt among other parameters, as follows:
+
+`$[algorithm]$[cost]$[salt][hash]`
+
+- 2 chars hash algorithm identifier prefix. `"$2a$" or "$2b$"` indicates BCrypt
+- Cost-factor (n). Represents the exponent used to determine how many iterations 2^n
+- 16-byte (128-bit) salt, base64 encoded to 22 characters
+- 24-byte (192-bit) hash, base64 encoded to 31 characters
+
+Example:
+```
+$2b$10$nOUIs5kJ7naTuTFkBy1veuK0kSxUFXfuaOKdOKf9xYT0KKIGSJwFa
+ |  |  |                     |
+ |  |  |                     hash-value = K0kSxUFXfuaOKdOKf9xYT0KKIGSJwFa
+ |  |  |
+ |  |  salt = nOUIs5kJ7naTuTFkBy1veu
+ |  |
+ |  cost-factor => 10 = 2^10 rounds
+ |
+ hash-algorithm identifier => 2b = BCrypt
+```
+
+## Testing
+
+If you create a pull request, tests better pass :)
+
+```
+npm install
+npm test
+```
+
+## Credits
+
+The code for this comes from a few sources:
+
+* blowfish.cc - OpenBSD
+* bcrypt.cc - OpenBSD
+* bcrypt::gen_salt - [gen_salt inclusion to bcrypt][bcryptgs]
+* bcrypt_node.cc - me
+
+## Contributors
+
+* [Antonio Salazar Cardozo][shadowfiend] - Early MacOS X support (when we used libbsd)
+* [Ben Glow][pixelglow] - Fixes for thread safety with async calls
+* [Van Nguyen][thegoleffect] - Found a timing attack in the comparator
+* [NewITFarmer][newitfarmer] - Initial Cygwin support
+* [David Trejo][dtrejo] - packaging fixes
+* [Alfred Westerveld][alfredwesterveld] - packaging fixes
+* [Vincent Côté-Roy][vincentr] - Testing around concurrency issues
+* [Lloyd Hilaiel][lloyd] - Documentation fixes
+* [Roman Shtylman][shtylman] - Code refactoring, general rot reduction, compile options, better memory management with delete and new, and an upgrade to libuv over eio/ev.
+* [Vadim Graboys][vadimg] - Code changes to support 0.5.5+
+* [Ben Noordhuis][bnoordhuis] - Fixed a thread safety issue in nodejs that was perfectly mappable to this module.
+* [Nate Rajlich][tootallnate] - Bindings and build process.
+* [Sean McArthur][seanmonstar] - Windows Support
+* [Fanie Oosthuysen][weareu] - Windows Support
+* [Amitosh Swain Mahapatra][recrsn] - $2b$ hash support, ES6 Promise support
+* [Nicola Del Gobbo][NickNaso] - Initial implementation with N-API
+
+## License
+Unless stated elsewhere, file headers or otherwise, the license as stated in the LICENSE file.
+
+[bcryptwiki]: https://en.wikipedia.org/wiki/Bcrypt
+[bcryptgs]: http://mail-index.netbsd.org/tech-crypto/2002/05/24/msg000204.html
+[codahale]: http://codahale.com/how-to-safely-store-a-password/
+[gh13]: https://github.com/ncb000gt/node.bcrypt.js/issues/13
+[jtr]: http://www.openwall.com/lists/oss-security/2011/06/20/2
+[depsinstall]: https://github.com/kelektiv/node.bcrypt.js/wiki/Installation-Instructions
+[timingatk]: https://codahale.com/a-lesson-in-timing-attacks/
+[wrap-around-bug]: https://github.com/kelektiv/node.bcrypt.js/wiki/Security-Issues-and-Concerns#bcrypt-wrap-around-bug-medium-severity
+[improper-nuls]: https://github.com/kelektiv/node.bcrypt.js/wiki/Security-Issues-and-Concerns#improper-nul-handling-medium-severity
+
+[shadowfiend]:https://github.com/Shadowfiend
+[thegoleffect]:https://github.com/thegoleffect
+[pixelglow]:https://github.com/pixelglow
+[dtrejo]:https://github.com/dtrejo
+[alfredwesterveld]:https://github.com/alfredwesterveld
+[newitfarmer]:https://github.com/newitfarmer
+[zooko]:https://twitter.com/zooko
+[vincentr]:https://twitter.com/vincentcr
+[lloyd]:https://github.com/lloyd
+[shtylman]:https://github.com/shtylman
+[vadimg]:https://github.com/vadimg
+[bnoordhuis]:https://github.com/bnoordhuis
+[tootallnate]:https://github.com/tootallnate
+[seanmonstar]:https://github.com/seanmonstar
+[weareu]:https://github.com/weareu
+[recrsn]:https://github.com/recrsn
+[NickNaso]: https://github.com/NickNaso
diff --git a/server/node_modules/bcrypt/SECURITY.md b/server/node_modules/bcrypt/SECURITY.md
new file mode 100644
index 0000000..c132dc8
--- /dev/null
+++ b/server/node_modules/bcrypt/SECURITY.md
@@ -0,0 +1,15 @@
+# Security Policy
+
+As with any software, `bcrypt` is likely to have bugs. Please report any security vulnerabilities responsibly
+
+## Supported Versions
+
+| Version | Supported          |
+| ------- | ------------------ |
+| 5.0.x   | :white_check_mark: |
+| < 5.0   | :x:                |
+
+## Reporting a Vulnerability
+
+If you are reporting a security vulnerability, please refrain from opening a GitHub issue and instead mail it to
+one of the maintainers listed in the README.
diff --git a/server/node_modules/bcrypt/bcrypt.js b/server/node_modules/bcrypt/bcrypt.js
new file mode 100644
index 0000000..62da525
--- /dev/null
+++ b/server/node_modules/bcrypt/bcrypt.js
@@ -0,0 +1,242 @@
+const path = require('path');
+const bindings = require('node-gyp-build')(path.resolve(__dirname));
+
+const crypto = require('crypto');
+
+const promises = require('./promises');
+
+/// generate a salt (sync)
+/// @param {Number} [rounds] number of rounds (default 10)
+/// @return {String} salt
+function genSaltSync(rounds, minor) {
+    // default 10 rounds
+    if (!rounds) {
+        rounds = 10;
+    } else if (typeof rounds !== 'number') {
+        throw new Error('rounds must be a number');
+    }
+
+    if (!minor) {
+        minor = 'b';
+    } else if (minor !== 'b' && minor !== 'a') {
+        throw new Error('minor must be either "a" or "b"');
+    }
+
+    return bindings.gen_salt_sync(minor, rounds, crypto.randomBytes(16));
+}
+
+/// generate a salt
+/// @param {Number} [rounds] number of rounds (default 10)
+/// @param {Function} cb callback(err, salt)
+function genSalt(rounds, minor, cb) {
+    let error;
+
+    // if callback is first argument, then use defaults for others
+    if (typeof arguments[0] === 'function') {
+        // have to set callback first otherwise arguments are overridden
+        cb = arguments[0];
+        rounds = 10;
+        minor = 'b';
+        // callback is second argument
+    } else if (typeof arguments[1] === 'function') {
+        // have to set callback first otherwise arguments are overridden
+        cb = arguments[1];
+        minor = 'b';
+    }
+
+    if (!cb) {
+        return promises.promise(genSalt, this, [rounds, minor]);
+    }
+
+    // default 10 rounds
+    if (!rounds) {
+        rounds = 10;
+    } else if (typeof rounds !== 'number') {
+        // callback error asynchronously
+        error = new Error('rounds must be a number');
+        return process.nextTick(function () {
+            cb(error);
+        });
+    }
+
+    if (!minor) {
+        minor = 'b'
+    } else if (minor !== 'b' && minor !== 'a') {
+        error = new Error('minor must be either "a" or "b"');
+        return process.nextTick(function () {
+            cb(error);
+        });
+    }
+
+    crypto.randomBytes(16, function (error, randomBytes) {
+        if (error) {
+            cb(error);
+            return;
+        }
+
+        bindings.gen_salt(minor, rounds, randomBytes, cb);
+    });
+}
+
+/// hash data using a salt
+/// @param {String|Buffer} data the data to encrypt
+/// @param {String} salt the salt to use when hashing
+/// @return {String} hash
+function hashSync(data, salt) {
+    if (data == null || salt == null) {
+        throw new Error('data and salt arguments required');
+    }
+
+    if (!(typeof data === 'string' || data instanceof Buffer) || (typeof salt !== 'string' && typeof salt !== 'number')) {
+        throw new Error('data must be a string or Buffer and salt must either be a salt string or a number of rounds');
+    }
+
+    if (typeof salt === 'number') {
+        salt = module.exports.genSaltSync(salt);
+    }
+
+    return bindings.encrypt_sync(data, salt);
+}
+
+/// hash data using a salt
+/// @param {String|Buffer} data the data to encrypt
+/// @param {String} salt the salt to use when hashing
+/// @param {Function} cb callback(err, hash)
+function hash(data, salt, cb) {
+    let error;
+
+    if (typeof data === 'function') {
+        error = new Error('data must be a string or Buffer and salt must either be a salt string or a number of rounds');
+        return process.nextTick(function () {
+            data(error);
+        });
+    }
+
+    if (typeof salt === 'function') {
+        error = new Error('data must be a string or Buffer and salt must either be a salt string or a number of rounds');
+        return process.nextTick(function () {
+            salt(error);
+        });
+    }
+
+    // cb exists but is not a function
+    // return a rejecting promise
+    if (cb && typeof cb !== 'function') {
+        return promises.reject(new Error('cb must be a function or null to return a Promise'));
+    }
+
+    if (!cb) {
+        return promises.promise(hash, this, [data, salt]);
+    }
+
+    if (data == null || salt == null) {
+        error = new Error('data and salt arguments required');
+        return process.nextTick(function () {
+            cb(error);
+        });
+    }
+
+    if (!(typeof data === 'string' || data instanceof Buffer) || (typeof salt !== 'string' && typeof salt !== 'number')) {
+        error = new Error('data must be a string or Buffer and salt must either be a salt string or a number of rounds');
+        return process.nextTick(function () {
+            cb(error);
+        });
+    }
+
+
+    if (typeof salt === 'number') {
+        return module.exports.genSalt(salt, function (err, salt) {
+            return bindings.encrypt(data, salt, cb);
+        });
+    }
+
+    return bindings.encrypt(data, salt, cb);
+}
+
+/// compare raw data to hash
+/// @param {String|Buffer} data the data to hash and compare
+/// @param {String} hash expected hash
+/// @return {bool} true if hashed data matches hash
+function compareSync(data, hash) {
+    if (data == null || hash == null) {
+        throw new Error('data and hash arguments required');
+    }
+
+    if (!(typeof data === 'string' || data instanceof Buffer) || typeof hash !== 'string') {
+        throw new Error('data must be a string or Buffer and hash must be a string');
+    }
+
+    return bindings.compare_sync(data, hash);
+}
+
+/// compare raw data to hash
+/// @param {String|Buffer} data the data to hash and compare
+/// @param {String} hash expected hash
+/// @param {Function} cb callback(err, matched) - matched is true if hashed data matches hash
+function compare(data, hash, cb) {
+    let error;
+
+    if (typeof data === 'function') {
+        error = new Error('data and hash arguments required');
+        return process.nextTick(function () {
+            data(error);
+        });
+    }
+
+    if (typeof hash === 'function') {
+        error = new Error('data and hash arguments required');
+        return process.nextTick(function () {
+            hash(error);
+        });
+    }
+
+    // cb exists but is not a function
+    // return a rejecting promise
+    if (cb && typeof cb !== 'function') {
+        return promises.reject(new Error('cb must be a function or null to return a Promise'));
+    }
+
+    if (!cb) {
+        return promises.promise(compare, this, [data, hash]);
+    }
+
+    if (data == null || hash == null) {
+        error = new Error('data and hash arguments required');
+        return process.nextTick(function () {
+            cb(error);
+        });
+    }
+
+    if (!(typeof data === 'string' || data instanceof Buffer) || typeof hash !== 'string') {
+        error = new Error('data and hash must be strings');
+        return process.nextTick(function () {
+            cb(error);
+        });
+    }
+
+    return bindings.compare(data, hash, cb);
+}
+
+/// @param {String} hash extract rounds from this hash
+/// @return {Number} the number of rounds used to encrypt a given hash
+function getRounds(hash) {
+    if (hash == null) {
+        throw new Error('hash argument required');
+    }
+
+    if (typeof hash !== 'string') {
+        throw new Error('hash must be a string');
+    }
+
+    return bindings.get_rounds(hash);
+}
+
+module.exports = {
+    genSaltSync,
+    genSalt,
+    hashSync,
+    hash,
+    compareSync,
+    compare,
+    getRounds,
+}
diff --git a/server/node_modules/bcrypt/binding.gyp b/server/node_modules/bcrypt/binding.gyp
new file mode 100644
index 0000000..46428be
--- /dev/null
+++ b/server/node_modules/bcrypt/binding.gyp
@@ -0,0 +1,49 @@
+{
+  "variables": {
+    "NODE_VERSION%":"<!(node -p \"process.versions.node.split(\\\".\\\")[0]\")"
+  },
+  'targets': [
+    {
+      'target_name': 'bcrypt_lib',
+      'sources': [
+        'src/blowfish.cc',
+        'src/bcrypt.cc',
+        'src/bcrypt_node.cc'
+      ],
+      'defines': [
+            '_GNU_SOURCE',
+      ],
+      'cflags!': [ '-fno-exceptions' ],
+      'cflags_cc!': [ '-fno-exceptions' ],
+      'dependencies': [
+          "<!(node -p \"require('node-addon-api').targets\"):node_addon_api_except",
+      ],
+      'conditions': [
+        ['OS=="win"', {
+          "msvs_settings": {
+            "VCCLCompilerTool": {
+              "ExceptionHandling": 1
+            }
+          },
+          'defines': [
+            'uint=unsigned int',
+          ]
+        }],
+        ['OS=="mac"', {
+          'cflags+': ['-fvisibility=hidden'],
+          "xcode_settings": {
+            "CLANG_CXX_LIBRARY": "libc++",
+            'GCC_ENABLE_CPP_EXCEPTIONS': 'YES',
+            'GCC_SYMBOLS_PRIVATE_EXTERN': 'YES', # -fvisibility=hidden
+          }
+        }],
+        ['OS=="zos" and NODE_VERSION <= 16',{
+            'cflags': [
+              '-qascii',
+            ],
+            'defines': ["NAPI_DISABLE_CPP_EXCEPTIONS"],
+        }],
+      ],
+    },
+  ]
+}
diff --git a/server/node_modules/bcrypt/build-all.sh b/server/node_modules/bcrypt/build-all.sh
new file mode 100755
index 0000000..75bf498
--- /dev/null
+++ b/server/node_modules/bcrypt/build-all.sh
@@ -0,0 +1,37 @@
+#!/bin/bash -ue
+
+CLEAN=${CLEAN:-""}
+RUN_TESTS=${RUN_TESTS:-true}
+
+if [ -n "$CLEAN" ]; then
+  rm -rf build build-tmp*
+  rm -rf lib/binding
+  rm -rf prebuilds
+fi
+
+npm i -g prebuildify@5 node-gyp@9
+npm ci
+#npm run build
+
+for PLATFORM in linux/amd64 linux/arm64/v8 linux/arm/v7; do
+  echo -- build for $PLATFORM --
+  BUILDER_NAME="bcryptjs-${PLATFORM//\/-}-builder"
+  docker build -t "$BUILDER_NAME" \
+      --build-arg RUN_TESTS="$RUN_TESTS" \
+      --platform "$PLATFORM" .
+  CONTAINER=$(docker create --platform "$PLATFORM" "$BUILDER_NAME")
+  docker cp "$CONTAINER:/usr/local/opt/bcrypt-js/prebuilds" .
+  docker rm "$CONTAINER"
+
+  echo -- build for $PLATFORM Alpine --
+  BUILDER_NAME="bcryptjs-${PLATFORM//\/-}-alpine-builder"
+  docker build -t "$BUILDER_NAME" -f Dockerfile-alpine \
+      --build-arg RUN_TESTS="$RUN_TESTS" \
+      --platform "$PLATFORM" .
+  CONTAINER=$(docker create --platform "$PLATFORM" "$BUILDER_NAME")
+  docker cp "$CONTAINER:/usr/local/opt/bcrypt-js/prebuilds" .
+  docker rm "$CONTAINER"
+
+done
+
+ls -lF prebuilds/
diff --git a/server/node_modules/bcrypt/examples/async_compare.js b/server/node_modules/bcrypt/examples/async_compare.js
new file mode 100644
index 0000000..4c17f88
--- /dev/null
+++ b/server/node_modules/bcrypt/examples/async_compare.js
@@ -0,0 +1,28 @@
+const bcrypt = require('../bcrypt');
+
+(async () => {
+    const start = Date.now();
+
+    // genSalt
+    const salt = await bcrypt.genSalt(10)
+    console.log('salt: ' + salt);
+    console.log('salt cb end: ' + (Date.now() - start) + 'ms');
+
+    // hash
+    const crypted = await bcrypt.hash('test', salt)
+    console.log('crypted: ' + crypted);
+    console.log('crypted cb end: ' + (Date.now() - start) + 'ms');
+    console.log('rounds used from hash:', bcrypt.getRounds(crypted));
+
+    // compare
+    const res = await bcrypt.compare('test', crypted)
+    console.log('compared true: ' + res);
+    console.log('compared true cb end: ' + (Date.now() - start) + 'ms');
+
+    // compare
+    const res2 = await bcrypt.compare('bacon', crypted)
+    console.log('compared false: ' + res2);
+    console.log('compared false cb end: ' + (Date.now() - start) + 'ms');
+
+    console.log('end: ' + (Date.now() - start) + 'ms');
+})();
diff --git a/server/node_modules/bcrypt/examples/forever_gen_salt.js b/server/node_modules/bcrypt/examples/forever_gen_salt.js
new file mode 100644
index 0000000..3f2ff2f
--- /dev/null
+++ b/server/node_modules/bcrypt/examples/forever_gen_salt.js
@@ -0,0 +1,8 @@
+const bcrypt = require('../bcrypt');
+
+(function printSalt() {
+  bcrypt.genSalt(10, (err, salt) => {
+    console.log('salt: ' + salt);
+    printSalt();
+  });
+})()
diff --git a/server/node_modules/bcrypt/package.json b/server/node_modules/bcrypt/package.json
new file mode 100644
index 0000000..c849897
--- /dev/null
+++ b/server/node_modules/bcrypt/package.json
@@ -0,0 +1,62 @@
+{
+  "name": "bcrypt",
+  "description": "A bcrypt library for NodeJS.",
+  "keywords": [
+    "bcrypt",
+    "password",
+    "auth",
+    "authentication",
+    "encryption",
+    "crypt",
+    "crypto"
+  ],
+  "main": "./bcrypt",
+  "version": "6.0.0",
+  "author": "Nick Campbell (https://github.com/ncb000gt)",
+  "engines": {
+    "node": ">= 18"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/kelektiv/node.bcrypt.js.git"
+  },
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/kelektiv/node.bcrypt.js/issues"
+  },
+  "scripts": {
+    "test": "jest",
+    "install": "node-gyp-build",
+    "build": "prebuildify --napi --tag-libc --strip"
+  },
+  "dependencies": {
+    "node-addon-api": "^8.3.0",
+    "node-gyp-build": "^4.8.4"
+  },
+  "devDependencies": {
+    "jest": "^29.7.0",
+    "prebuildify": "^6.0.1"
+  },
+  "contributors": [
+    "Antonio Salazar Cardozo <savedfastcool@gmail.com> (https://github.com/Shadowfiend)",
+    "Van Nguyen <the.gol.effect@gmail.com> (https://github.com/thegoleffect)",
+    "David Trejo <david@dtrejo.com> (https://github.com/dtrejo)",
+    "Ben Glow <glen.low@pixelglow.com> (https://github.com/pixelglow)",
+    "NewITFarmer.com <> (https://github.com/newitfarmer)",
+    "Alfred Westerveld <alfredwesterveld@gmail.com> (https://github.com/alfredwesterveld)",
+    "Vincent Côté-Roy <vincentcr@gmail.com> (https://github.com/vincentcr)",
+    "Lloyd Hilaiel <lloyd@hilaiel.com> (https://github.com/lloyd)",
+    "Roman Shtylman <shtylman@gmail.com> (https://github.com/shtylman)",
+    "Vadim Graboys <dimva13@gmail.com> (https://github.com/vadimg)",
+    "Ben Noorduis <> (https://github.com/bnoordhuis)",
+    "Nate Rajlich <nathan@tootallnate.net> (https://github.com/tootallnate)",
+    "Sean McArthur <sean.monstar@gmail.com> (https://github.com/seanmonstar)",
+    "Fanie Oosthuysen <fanie.oosthuysen@gmail.com> (https://github.com/weareu)",
+    "Amitosh Swain Mahapatra <amitosh.swain@gmail.com> (https://github.com/Agathver)",
+    "Corbin Crutchley <crutchcorn@gmail.com> (https://github.com/crutchcorn)",
+    "Nicola Del Gobbo <nicoladelgobbo@gmail.com> (https://github.com/NickNaso)"
+  ],
+  "binary": {
+    "module_name": "bcrypt_lib"
+  }
+}
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diff --git a/server/node_modules/bcrypt/prebuilds/win32-x64/bcrypt.node b/server/node_modules/bcrypt/prebuilds/win32-x64/bcrypt.node
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diff --git a/server/node_modules/bcrypt/promises.js b/server/node_modules/bcrypt/promises.js
new file mode 100644
index 0000000..6685cc2
--- /dev/null
+++ b/server/node_modules/bcrypt/promises.js
@@ -0,0 +1,45 @@
+let Promise = global.Promise;
+
+/// encapsulate a method with a node-style callback in a Promise
+/// @param {object} 'this' of the encapsulated function
+/// @param {function} function to be encapsulated
+/// @param {Array-like} args to be passed to the called function
+/// @return {Promise} a Promise encapsulating the function
+function promise(fn, context, args) {
+    if (!Array.isArray(args)) {
+        args = Array.prototype.slice.call(args);
+    }
+
+    if (typeof fn !== 'function') {
+        return Promise.reject(new Error('fn must be a function'));
+    }
+
+    return new Promise((resolve, reject) => {
+        args.push((err, data) => {
+            if (err) {
+                reject(err);
+            } else {
+                resolve(data);
+            }
+        });
+
+        fn.apply(context, args);
+    });
+}
+
+/// @param {err} the error to be thrown
+function reject(err) {
+    return Promise.reject(err);
+}
+
+/// changes the promise implementation that bcrypt uses
+/// @param {Promise} the implementation to use
+function use(promise) {
+    Promise = promise;
+}
+
+module.exports = {
+    promise,
+    reject,
+    use
+}
diff --git a/server/node_modules/bcrypt/src/bcrypt.cc b/server/node_modules/bcrypt/src/bcrypt.cc
new file mode 100644
index 0000000..bd8c573
--- /dev/null
+++ b/server/node_modules/bcrypt/src/bcrypt.cc
@@ -0,0 +1,315 @@
+/*	$OpenBSD: bcrypt.c,v 1.31 2014/03/22 23:02:03 tedu Exp $	*/
+
+/*
+ * Copyright (c) 1997 Niels Provos <provos@umich.edu>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* This password hashing algorithm was designed by David Mazieres
+ * <dm@lcs.mit.edu> and works as follows:
+ *
+ * 1. state := InitState ()
+ * 2. state := ExpandKey (state, salt, password)
+ * 3. REPEAT rounds:
+ *    	state := ExpandKey (state, 0, password)
+ *    state := ExpandKey (state, 0, salt)
+ * 4. ctext := "OrpheanBeholderScryDoubt"
+ * 5. REPEAT 64:
+ *    	ctext := Encrypt_ECB (state, ctext);
+ * 6. RETURN Concatenate (salt, ctext);
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <string.h>
+
+#include "node_blf.h"
+
+#ifdef _WIN32
+#define snprintf _snprintf
+#endif
+
+//#if !defined(__APPLE__) && !defined(__MACH__)
+//#include "bsd/stdlib.h"
+//#endif
+
+/* This implementation is adaptable to current computing power.
+ * You can have up to 2^31 rounds which should be enough for some
+ * time to come.
+ */
+
+static void encode_base64(u_int8_t *, u_int8_t *, u_int16_t);
+static void decode_base64(u_int8_t *, u_int16_t, u_int8_t *);
+
+const static char* error = ":";
+
+const static u_int8_t Base64Code[] =
+"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+
+const static u_int8_t index_64[128] = {
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 0, 1, 54, 55,
+	56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
+	255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
+	7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+	17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
+	255, 255, 255, 255, 255, 255, 28, 29, 30,
+	31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+	41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
+	51, 52, 53, 255, 255, 255, 255, 255
+};
+#define CHAR64(c)  ( (c) > 127 ? 255 : index_64[(c)])
+
+static void
+decode_base64(u_int8_t *buffer, u_int16_t len, u_int8_t *data)
+{
+	u_int8_t *bp = buffer;
+	u_int8_t *p = data;
+	u_int8_t c1, c2, c3, c4;
+	while (bp < buffer + len) {
+		c1 = CHAR64(*p);
+		c2 = CHAR64(*(p + 1));
+
+		/* Invalid data */
+		if (c1 == 255 || c2 == 255)
+			break;
+
+		*bp++ = (c1 << 2) | ((c2 & 0x30) >> 4);
+		if (bp >= buffer + len)
+			break;
+
+		c3 = CHAR64(*(p + 2));
+		if (c3 == 255)
+			break;
+
+		*bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
+		if (bp >= buffer + len)
+			break;
+
+		c4 = CHAR64(*(p + 3));
+		if (c4 == 255)
+			break;
+		*bp++ = ((c3 & 0x03) << 6) | c4;
+
+		p += 4;
+	}
+}
+
+void
+encode_salt(char *salt, u_int8_t *csalt, char minor, u_int16_t clen, u_int8_t logr)
+{
+	salt[0] = '$';
+	salt[1] = BCRYPT_VERSION;
+	salt[2] = minor;
+	salt[3] = '$';
+
+    // Max rounds are 31
+	snprintf(salt + 4, 4, "%2.2u$", logr & 0x001F);
+
+	encode_base64((u_int8_t *) salt + 7, csalt, clen);
+}
+
+
+/* Generates a salt for this version of crypt.
+   Since versions may change. Keeping this here
+   seems sensible.
+   from: http://mail-index.netbsd.org/tech-crypto/2002/05/24/msg000204.html
+*/
+void
+bcrypt_gensalt(char minor, u_int8_t log_rounds, u_int8_t *seed, char *gsalt)
+{
+	if (log_rounds < 4)
+		log_rounds = 4;
+	else if (log_rounds > 31)
+		log_rounds = 31;
+
+	encode_salt(gsalt, seed, minor, BCRYPT_MAXSALT, log_rounds);
+}
+
+/* We handle $Vers$log2(NumRounds)$salt+passwd$
+   i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */
+
+void
+bcrypt(const char *key, size_t key_len, const char *salt, char *encrypted)
+{
+	blf_ctx state;
+	u_int32_t rounds, i, k;
+	u_int16_t j;
+	u_int8_t salt_len, logr, minor;
+	u_int8_t ciphertext[4 * BCRYPT_BLOCKS+1] = "OrpheanBeholderScryDoubt";
+	u_int8_t csalt[BCRYPT_MAXSALT];
+	u_int32_t cdata[BCRYPT_BLOCKS];
+	int n;
+
+	/* Discard "$" identifier */
+	salt++;
+
+	if (*salt > BCRYPT_VERSION) {
+		/* How do I handle errors ? Return ':' */
+		strcpy(encrypted, error);
+		return;
+	}
+
+	/* Check for minor versions */
+	if (salt[1] != '$') {
+		 switch (salt[1]) {
+		 case 'a': /* 'ab' should not yield the same as 'abab' */
+		 case 'b': /* cap input length at 72 bytes */
+			 minor = salt[1];
+			 salt++;
+			 break;
+		 default:
+			 strcpy(encrypted, error);
+			 return;
+		 }
+	} else
+		 minor = 0;
+
+	/* Discard version + "$" identifier */
+	salt += 2;
+
+	if (salt[2] != '$') {
+		/* Out of sync with passwd entry */
+		strcpy(encrypted, error);
+		return;
+	}
+
+	/* Computer power doesn't increase linear, 2^x should be fine */
+	n = atoi(salt);
+	if (n > 31 || n < 0) {
+		strcpy(encrypted, error);
+		return;
+	}
+	logr = (u_int8_t)n;
+	if ((rounds = (u_int32_t) 1 << logr) < BCRYPT_MINROUNDS) {
+		strcpy(encrypted, error);
+		return;
+	}
+
+	/* Discard num rounds + "$" identifier */
+	salt += 3;
+
+	if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT) {
+		strcpy(encrypted, error);
+		return;
+	}
+
+	/* We dont want the base64 salt but the raw data */
+	decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt);
+	salt_len = BCRYPT_MAXSALT;
+	if (minor <= 'a')
+		key_len = (u_int8_t)(key_len + (minor >= 'a' ? 1 : 0));
+	else
+	{
+		/* cap key_len at the actual maximum supported
+		* length here to avoid integer wraparound */
+		if (key_len > 72)
+			key_len = 72;
+		key_len++; /* include the NUL */
+	}
+
+
+	/* Setting up S-Boxes and Subkeys */
+	Blowfish_initstate(&state);
+	Blowfish_expandstate(&state, csalt, salt_len,
+		(u_int8_t *) key, key_len);
+	for (k = 0; k < rounds; k++) {
+		Blowfish_expand0state(&state, (u_int8_t *) key, key_len);
+		Blowfish_expand0state(&state, csalt, salt_len);
+	}
+
+ 	/* This can be precomputed later */
+	j = 0;
+	for (i = 0; i < BCRYPT_BLOCKS; i++)
+		cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
+
+	/* Now do the encryption */
+	for (k = 0; k < 64; k++)
+		blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
+
+	for (i = 0; i < BCRYPT_BLOCKS; i++) {
+		ciphertext[4 * i + 3] = cdata[i] & 0xff;
+		cdata[i] = cdata[i] >> 8;
+		ciphertext[4 * i + 2] = cdata[i] & 0xff;
+		cdata[i] = cdata[i] >> 8;
+		ciphertext[4 * i + 1] = cdata[i] & 0xff;
+		cdata[i] = cdata[i] >> 8;
+		ciphertext[4 * i + 0] = cdata[i] & 0xff;
+	}
+
+	i = 0;
+	encrypted[i++] = '$';
+	encrypted[i++] = BCRYPT_VERSION;
+	if (minor)
+		encrypted[i++] = minor;
+	encrypted[i++] = '$';
+
+	snprintf(encrypted + i, 4, "%2.2u$", logr & 0x001F);
+
+	encode_base64((u_int8_t *) encrypted + i + 3, csalt, BCRYPT_MAXSALT);
+	encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext,
+		4 * BCRYPT_BLOCKS - 1);
+	memset(&state, 0, sizeof(state));
+	memset(ciphertext, 0, sizeof(ciphertext));
+	memset(csalt, 0, sizeof(csalt));
+	memset(cdata, 0, sizeof(cdata));
+}
+
+u_int32_t bcrypt_get_rounds(const char * hash)
+{
+  /* skip past the leading "$" */
+  if (!hash || *(hash++) != '$') return 0;
+
+  /* skip past version */
+  if (0 == (*hash++)) return 0;
+  if (*hash && *hash != '$') hash++;
+  if (*hash++ != '$') return 0;
+
+  return  atoi(hash);
+}
+
+static void
+encode_base64(u_int8_t *buffer, u_int8_t *data, u_int16_t len)
+{
+	u_int8_t *bp = buffer;
+	u_int8_t *p = data;
+	u_int8_t c1, c2;
+	while (p < data + len) {
+		c1 = *p++;
+		*bp++ = Base64Code[(c1 >> 2)];
+		c1 = (c1 & 0x03) << 4;
+		if (p >= data + len) {
+			*bp++ = Base64Code[c1];
+			break;
+		}
+		c2 = *p++;
+		c1 |= (c2 >> 4) & 0x0f;
+		*bp++ = Base64Code[c1];
+		c1 = (c2 & 0x0f) << 2;
+		if (p >= data + len) {
+			*bp++ = Base64Code[c1];
+			break;
+		}
+		c2 = *p++;
+		c1 |= (c2 >> 6) & 0x03;
+		*bp++ = Base64Code[c1];
+		*bp++ = Base64Code[c2 & 0x3f];
+	}
+	*bp = '\0';
+}
diff --git a/server/node_modules/bcrypt/src/bcrypt_node.cc b/server/node_modules/bcrypt/src/bcrypt_node.cc
new file mode 100644
index 0000000..2f072a4
--- /dev/null
+++ b/server/node_modules/bcrypt/src/bcrypt_node.cc
@@ -0,0 +1,288 @@
+#define NAPI_VERSION 3
+
+#include <napi.h>
+
+#include <string>
+#include <cstring>
+#include <vector>
+#include <stdlib.h> // atoi
+
+#include "node_blf.h"
+
+#define NODE_LESS_THAN (!(NODE_VERSION_AT_LEAST(0, 5, 4)))
+
+namespace {
+
+    bool ValidateSalt(const char* salt) {
+
+        if (!salt || *salt != '$') {
+            return false;
+        }
+
+        // discard $
+        salt++;
+
+        if (*salt > BCRYPT_VERSION) {
+            return false;
+        }
+
+        if (salt[1] != '$') {
+            switch (salt[1]) {
+            case 'a':
+            case 'b':
+                salt++;
+                break;
+            default:
+                return false;
+            }
+        }
+
+        // discard version + $
+        salt += 2;
+
+        if (salt[2] != '$') {
+            return false;
+        }
+
+        int n = atoi(salt);
+        if (n > 31 || n < 0) {
+            return false;
+        }
+
+        if (((uint8_t)1 << (uint8_t)n) < BCRYPT_MINROUNDS) {
+            return false;
+        }
+
+        salt += 3;
+        if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT) {
+            return false;
+        }
+
+        return true;
+    }
+
+    inline char ToCharVersion(const std::string& str) {
+        return str[0];
+    }
+
+    /* SALT GENERATION */
+
+    class SaltAsyncWorker : public Napi::AsyncWorker {
+        public:
+            SaltAsyncWorker(const Napi::Function& callback, const std::string& seed, ssize_t rounds, char minor_ver)
+                : Napi::AsyncWorker(callback, "bcrypt:SaltAsyncWorker"), seed(seed), rounds(rounds), minor_ver(minor_ver) {
+            }
+
+            ~SaltAsyncWorker() {}
+
+            void Execute() {
+                bcrypt_gensalt(minor_ver, rounds, (u_int8_t *)&seed[0], salt);
+            }
+
+            void OnOK() {
+                Napi::HandleScope scope(Env());
+                Callback().Call({Env().Undefined(), Napi::String::New(Env(), salt)});
+            }
+
+        private:
+            std::string seed;
+            ssize_t rounds;
+            char minor_ver;
+            char salt[_SALT_LEN];
+    };
+
+    Napi::Value GenerateSalt(const Napi::CallbackInfo& info) {
+        Napi::Env env = info.Env();
+        if (info.Length() < 4) {
+            throw Napi::TypeError::New(env, "4 arguments expected");
+        }
+        if (!info[0].IsString()) {
+            throw Napi::TypeError::New(env, "First argument must be a string");
+        }
+        if (!info[2].IsBuffer() || (info[2].As<Napi::Buffer<char>>()).Length() != 16) {
+            throw Napi::TypeError::New(env, "Second argument must be a 16 byte Buffer");
+        }
+
+        const char minor_ver = ToCharVersion(info[0].As<Napi::String>());
+        const int32_t rounds = info[1].As<Napi::Number>();
+        Napi::Buffer<char> seed = info[2].As<Napi::Buffer<char>>();
+        Napi::Function callback = info[3].As<Napi::Function>();
+        SaltAsyncWorker* saltWorker = new SaltAsyncWorker(callback, std::string(seed.Data(), 16), rounds, minor_ver);
+        saltWorker->Queue();
+        return env.Undefined();
+    }
+
+    Napi::Value GenerateSaltSync(const Napi::CallbackInfo& info) {
+        Napi::Env env = info.Env();
+        if (info.Length() < 3) {
+            throw Napi::TypeError::New(env, "3 arguments expected");
+        }
+        if (!info[0].IsString()) {
+            throw Napi::TypeError::New(env, "First argument must be a string");
+        }
+        if (!info[2].IsBuffer() || (info[2].As<Napi::Buffer<char>>()).Length() != 16) {
+            throw Napi::TypeError::New(env, "Third argument must be a 16 byte Buffer");
+        }
+        const char minor_ver = ToCharVersion(info[0].As<Napi::String>());
+        const int32_t rounds = info[1].As<Napi::Number>();
+        Napi::Buffer<u_int8_t> buffer = info[2].As<Napi::Buffer<u_int8_t>>();
+        u_int8_t* seed = (u_int8_t*) buffer.Data();
+        char salt[_SALT_LEN];
+        bcrypt_gensalt(minor_ver, rounds, seed, salt);
+        return Napi::String::New(env, salt, strlen(salt));
+    }
+
+    inline std::string BufferToString(const Napi::Buffer<char> &buf) {
+        return std::string(buf.Data(), buf.Length());
+    }
+
+    /* ENCRYPT DATA - USED TO BE HASHPW */
+
+    class EncryptAsyncWorker : public Napi::AsyncWorker {
+        public:
+            EncryptAsyncWorker(const Napi::Function& callback, const std::string& input, const std::string& salt)
+                : Napi::AsyncWorker(callback, "bcrypt:EncryptAsyncWorker"), input(input), salt(salt) {
+            }
+
+            ~EncryptAsyncWorker() {}
+
+            void Execute() {
+                if (!(ValidateSalt(salt.c_str()))) {
+                    SetError("Invalid salt. Salt must be in the form of: $Vers$log2(NumRounds)$saltvalue");
+                }
+                bcrypt(input.c_str(), input.length(), salt.c_str(), bcrypted);
+            }
+
+            void OnOK() {
+                Napi::HandleScope scope(Env());
+                Callback().Call({Env().Undefined(),Napi::String::New(Env(), bcrypted)});
+            }
+        private:
+            std::string input;
+            std::string salt;
+            char bcrypted[_PASSWORD_LEN];
+    };
+
+    Napi::Value Encrypt(const Napi::CallbackInfo& info) {
+        if (info.Length() < 3) {
+            throw Napi::TypeError::New(info.Env(), "3 arguments expected");
+        }
+        std::string data = info[0].IsBuffer()
+            ? BufferToString(info[0].As<Napi::Buffer<char>>())
+            : info[0].As<Napi::String>();
+        std::string salt = info[1].As<Napi::String>();
+        Napi::Function callback = info[2].As<Napi::Function>();
+        EncryptAsyncWorker* encryptWorker = new EncryptAsyncWorker(callback, data, salt);
+        encryptWorker->Queue();
+        return info.Env().Undefined();
+    }
+
+    Napi::Value EncryptSync(const Napi::CallbackInfo& info) {
+        Napi::Env env = info.Env();
+        if (info.Length() < 2) {
+            throw Napi::TypeError::New(info.Env(), "2 arguments expected");
+        }
+        std::string data = info[0].IsBuffer()
+            ? BufferToString(info[0].As<Napi::Buffer<char>>())
+            : info[0].As<Napi::String>();
+        std::string salt = info[1].As<Napi::String>();
+        if (!(ValidateSalt(salt.c_str()))) {
+            throw Napi::Error::New(env, "Invalid salt. Salt must be in the form of: $Vers$log2(NumRounds)$saltvalue");
+        }
+        char bcrypted[_PASSWORD_LEN];
+        bcrypt(data.c_str(), data.length(), salt.c_str(), bcrypted);
+        return Napi::String::New(env, bcrypted, strlen(bcrypted));
+    }
+
+    /* COMPARATOR */
+    inline bool CompareStrings(const char* s1, const char* s2) {
+        return strcmp(s1, s2) == 0;
+    }
+
+    class CompareAsyncWorker : public Napi::AsyncWorker {
+        public:
+            CompareAsyncWorker(const Napi::Function& callback, const std::string& input, const std::string& encrypted)
+                : Napi::AsyncWorker(callback, "bcrypt:CompareAsyncWorker"), input(input), encrypted(encrypted) {
+                result = false;
+            }
+
+            ~CompareAsyncWorker() {}
+
+            void Execute() {
+                char bcrypted[_PASSWORD_LEN];
+                if (ValidateSalt(encrypted.c_str())) {
+                    bcrypt(input.c_str(), input.length(), encrypted.c_str(), bcrypted);
+                    result = CompareStrings(bcrypted, encrypted.c_str());
+                }
+            }
+
+            void OnOK() {
+                Napi::HandleScope scope(Env());
+                Callback().Call({Env().Undefined(), Napi::Boolean::New(Env(), result)});
+            }
+
+        private:
+            std::string input;
+            std::string encrypted;
+            bool result;
+    };
+
+    Napi::Value Compare(const Napi::CallbackInfo& info) {
+        if (info.Length() < 3) {
+                throw Napi::TypeError::New(info.Env(), "3 arguments expected");
+        }
+        std::string input = info[0].IsBuffer()
+            ? BufferToString(info[0].As<Napi::Buffer<char>>())
+            : info[0].As<Napi::String>();
+        std::string encrypted = info[1].As<Napi::String>();
+        Napi::Function callback = info[2].As<Napi::Function>();
+        CompareAsyncWorker* compareWorker = new CompareAsyncWorker(callback, input, encrypted);
+        compareWorker->Queue();
+        return info.Env().Undefined();
+    }
+
+    Napi::Value CompareSync(const Napi::CallbackInfo& info) {
+        Napi::Env env = info.Env();
+        if (info.Length() < 2) {
+            throw Napi::TypeError::New(info.Env(), "2 arguments expected");
+        }
+        std::string pw = info[0].IsBuffer()
+            ? BufferToString(info[0].As<Napi::Buffer<char>>())
+            : info[0].As<Napi::String>();
+        std::string hash = info[1].As<Napi::String>();
+        char bcrypted[_PASSWORD_LEN];
+        if (ValidateSalt(hash.c_str())) {
+            bcrypt(pw.c_str(), pw.length(), hash.c_str(), bcrypted);
+            return Napi::Boolean::New(env, CompareStrings(bcrypted, hash.c_str()));
+        } else {
+            return Napi::Boolean::New(env, false);
+        }
+    }
+
+    Napi::Value GetRounds(const Napi::CallbackInfo& info) {
+        Napi::Env env = info.Env();
+        if (info.Length() < 1) {
+            throw Napi::TypeError::New(env, "1 argument expected");
+        }
+        std::string hash =  info[0].As<Napi::String>();
+        u_int32_t rounds;
+        if (!(rounds = bcrypt_get_rounds(hash.c_str()))) {
+            throw Napi::Error::New(env, "invalid hash provided");
+        }
+        return Napi::Number::New(env, rounds);
+    }
+
+} // anonymous namespace
+
+Napi::Object init(Napi::Env env, Napi::Object exports) {
+    exports.Set(Napi::String::New(env, "gen_salt_sync"), Napi::Function::New(env, GenerateSaltSync));
+    exports.Set(Napi::String::New(env, "encrypt_sync"), Napi::Function::New(env, EncryptSync));
+    exports.Set(Napi::String::New(env, "compare_sync"), Napi::Function::New(env, CompareSync));
+    exports.Set(Napi::String::New(env, "get_rounds"), Napi::Function::New(env, GetRounds));
+    exports.Set(Napi::String::New(env, "gen_salt"), Napi::Function::New(env, GenerateSalt));
+    exports.Set(Napi::String::New(env, "encrypt"), Napi::Function::New(env, Encrypt));
+    exports.Set(Napi::String::New(env, "compare"), Napi::Function::New(env, Compare));
+    return exports;
+}
+
+NODE_API_MODULE(NODE_GYP_MODULE_NAME, init)
diff --git a/server/node_modules/bcrypt/src/blowfish.cc b/server/node_modules/bcrypt/src/blowfish.cc
new file mode 100644
index 0000000..1fc6cf1
--- /dev/null
+++ b/server/node_modules/bcrypt/src/blowfish.cc
@@ -0,0 +1,679 @@
+/* $OpenBSD: blowfish.c,v 1.18 2004/11/02 17:23:26 hshoexer Exp $ */
+/*
+ * Blowfish block cipher for OpenBSD
+ * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
+ * All rights reserved.
+ *
+ * Implementation advice by David Mazieres <dm@lcs.mit.edu>.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed by Niels Provos.
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This code is derived from section 14.3 and the given source
+ * in section V of Applied Cryptography, second edition.
+ * Blowfish is an unpatented fast block cipher designed by
+ * Bruce Schneier.
+ */
+
+#include "node_blf.h"
+
+#undef inline
+#ifdef __GNUC__
+#define inline __inline
+#else				/* !__GNUC__ */
+#define inline
+#endif				/* !__GNUC__ */
+
+/* Function for Feistel Networks */
+
+#define F(s, x) ((((s)[        (((x)>>24)&0xFF)]  \
+		 + (s)[0x100 + (((x)>>16)&0xFF)]) \
+		 ^ (s)[0x200 + (((x)>> 8)&0xFF)]) \
+		 + (s)[0x300 + ( (x)     &0xFF)])
+
+#define BLFRND(s,p,i,j,n) (i ^= F(s,j) ^ (p)[n])
+
+void
+Blowfish_encipher(blf_ctx *c, u_int32_t *xl, u_int32_t *xr)
+{
+	u_int32_t Xl;
+	u_int32_t Xr;
+	u_int32_t *s = c->S[0];
+	u_int32_t *p = c->P;
+
+	Xl = *xl;
+	Xr = *xr;
+
+	Xl ^= p[0];
+	BLFRND(s, p, Xr, Xl, 1); BLFRND(s, p, Xl, Xr, 2);
+	BLFRND(s, p, Xr, Xl, 3); BLFRND(s, p, Xl, Xr, 4);
+	BLFRND(s, p, Xr, Xl, 5); BLFRND(s, p, Xl, Xr, 6);
+	BLFRND(s, p, Xr, Xl, 7); BLFRND(s, p, Xl, Xr, 8);
+	BLFRND(s, p, Xr, Xl, 9); BLFRND(s, p, Xl, Xr, 10);
+	BLFRND(s, p, Xr, Xl, 11); BLFRND(s, p, Xl, Xr, 12);
+	BLFRND(s, p, Xr, Xl, 13); BLFRND(s, p, Xl, Xr, 14);
+	BLFRND(s, p, Xr, Xl, 15); BLFRND(s, p, Xl, Xr, 16);
+
+	*xl = Xr ^ p[17];
+	*xr = Xl;
+}
+
+void
+Blowfish_decipher(blf_ctx *c, u_int32_t *xl, u_int32_t *xr)
+{
+	u_int32_t Xl;
+	u_int32_t Xr;
+	u_int32_t *s = c->S[0];
+	u_int32_t *p = c->P;
+
+	Xl = *xl;
+	Xr = *xr;
+
+	Xl ^= p[17];
+	BLFRND(s, p, Xr, Xl, 16); BLFRND(s, p, Xl, Xr, 15);
+	BLFRND(s, p, Xr, Xl, 14); BLFRND(s, p, Xl, Xr, 13);
+	BLFRND(s, p, Xr, Xl, 12); BLFRND(s, p, Xl, Xr, 11);
+	BLFRND(s, p, Xr, Xl, 10); BLFRND(s, p, Xl, Xr, 9);
+	BLFRND(s, p, Xr, Xl, 8); BLFRND(s, p, Xl, Xr, 7);
+	BLFRND(s, p, Xr, Xl, 6); BLFRND(s, p, Xl, Xr, 5);
+	BLFRND(s, p, Xr, Xl, 4); BLFRND(s, p, Xl, Xr, 3);
+	BLFRND(s, p, Xr, Xl, 2); BLFRND(s, p, Xl, Xr, 1);
+
+	*xl = Xr ^ p[0];
+	*xr = Xl;
+}
+
+void
+Blowfish_initstate(blf_ctx *c)
+{
+	/* P-box and S-box tables initialized with digits of Pi */
+
+	static const blf_ctx initstate =
+	{ {
+		{
+			0xd1310ba6, 0x98dfb5ac, 0x2ffd72db, 0xd01adfb7,
+			0xb8e1afed, 0x6a267e96, 0xba7c9045, 0xf12c7f99,
+			0x24a19947, 0xb3916cf7, 0x0801f2e2, 0x858efc16,
+			0x636920d8, 0x71574e69, 0xa458fea3, 0xf4933d7e,
+			0x0d95748f, 0x728eb658, 0x718bcd58, 0x82154aee,
+			0x7b54a41d, 0xc25a59b5, 0x9c30d539, 0x2af26013,
+			0xc5d1b023, 0x286085f0, 0xca417918, 0xb8db38ef,
+			0x8e79dcb0, 0x603a180e, 0x6c9e0e8b, 0xb01e8a3e,
+			0xd71577c1, 0xbd314b27, 0x78af2fda, 0x55605c60,
+			0xe65525f3, 0xaa55ab94, 0x57489862, 0x63e81440,
+			0x55ca396a, 0x2aab10b6, 0xb4cc5c34, 0x1141e8ce,
+			0xa15486af, 0x7c72e993, 0xb3ee1411, 0x636fbc2a,
+			0x2ba9c55d, 0x741831f6, 0xce5c3e16, 0x9b87931e,
+			0xafd6ba33, 0x6c24cf5c, 0x7a325381, 0x28958677,
+			0x3b8f4898, 0x6b4bb9af, 0xc4bfe81b, 0x66282193,
+			0x61d809cc, 0xfb21a991, 0x487cac60, 0x5dec8032,
+			0xef845d5d, 0xe98575b1, 0xdc262302, 0xeb651b88,
+			0x23893e81, 0xd396acc5, 0x0f6d6ff3, 0x83f44239,
+			0x2e0b4482, 0xa4842004, 0x69c8f04a, 0x9e1f9b5e,
+			0x21c66842, 0xf6e96c9a, 0x670c9c61, 0xabd388f0,
+			0x6a51a0d2, 0xd8542f68, 0x960fa728, 0xab5133a3,
+			0x6eef0b6c, 0x137a3be4, 0xba3bf050, 0x7efb2a98,
+			0xa1f1651d, 0x39af0176, 0x66ca593e, 0x82430e88,
+			0x8cee8619, 0x456f9fb4, 0x7d84a5c3, 0x3b8b5ebe,
+			0xe06f75d8, 0x85c12073, 0x401a449f, 0x56c16aa6,
+			0x4ed3aa62, 0x363f7706, 0x1bfedf72, 0x429b023d,
+			0x37d0d724, 0xd00a1248, 0xdb0fead3, 0x49f1c09b,
+			0x075372c9, 0x80991b7b, 0x25d479d8, 0xf6e8def7,
+			0xe3fe501a, 0xb6794c3b, 0x976ce0bd, 0x04c006ba,
+			0xc1a94fb6, 0x409f60c4, 0x5e5c9ec2, 0x196a2463,
+			0x68fb6faf, 0x3e6c53b5, 0x1339b2eb, 0x3b52ec6f,
+			0x6dfc511f, 0x9b30952c, 0xcc814544, 0xaf5ebd09,
+			0xbee3d004, 0xde334afd, 0x660f2807, 0x192e4bb3,
+			0xc0cba857, 0x45c8740f, 0xd20b5f39, 0xb9d3fbdb,
+			0x5579c0bd, 0x1a60320a, 0xd6a100c6, 0x402c7279,
+			0x679f25fe, 0xfb1fa3cc, 0x8ea5e9f8, 0xdb3222f8,
+			0x3c7516df, 0xfd616b15, 0x2f501ec8, 0xad0552ab,
+			0x323db5fa, 0xfd238760, 0x53317b48, 0x3e00df82,
+			0x9e5c57bb, 0xca6f8ca0, 0x1a87562e, 0xdf1769db,
+			0xd542a8f6, 0x287effc3, 0xac6732c6, 0x8c4f5573,
+			0x695b27b0, 0xbbca58c8, 0xe1ffa35d, 0xb8f011a0,
+			0x10fa3d98, 0xfd2183b8, 0x4afcb56c, 0x2dd1d35b,
+			0x9a53e479, 0xb6f84565, 0xd28e49bc, 0x4bfb9790,
+			0xe1ddf2da, 0xa4cb7e33, 0x62fb1341, 0xcee4c6e8,
+			0xef20cada, 0x36774c01, 0xd07e9efe, 0x2bf11fb4,
+			0x95dbda4d, 0xae909198, 0xeaad8e71, 0x6b93d5a0,
+			0xd08ed1d0, 0xafc725e0, 0x8e3c5b2f, 0x8e7594b7,
+			0x8ff6e2fb, 0xf2122b64, 0x8888b812, 0x900df01c,
+			0x4fad5ea0, 0x688fc31c, 0xd1cff191, 0xb3a8c1ad,
+			0x2f2f2218, 0xbe0e1777, 0xea752dfe, 0x8b021fa1,
+			0xe5a0cc0f, 0xb56f74e8, 0x18acf3d6, 0xce89e299,
+			0xb4a84fe0, 0xfd13e0b7, 0x7cc43b81, 0xd2ada8d9,
+			0x165fa266, 0x80957705, 0x93cc7314, 0x211a1477,
+			0xe6ad2065, 0x77b5fa86, 0xc75442f5, 0xfb9d35cf,
+			0xebcdaf0c, 0x7b3e89a0, 0xd6411bd3, 0xae1e7e49,
+			0x00250e2d, 0x2071b35e, 0x226800bb, 0x57b8e0af,
+			0x2464369b, 0xf009b91e, 0x5563911d, 0x59dfa6aa,
+			0x78c14389, 0xd95a537f, 0x207d5ba2, 0x02e5b9c5,
+			0x83260376, 0x6295cfa9, 0x11c81968, 0x4e734a41,
+			0xb3472dca, 0x7b14a94a, 0x1b510052, 0x9a532915,
+			0xd60f573f, 0xbc9bc6e4, 0x2b60a476, 0x81e67400,
+			0x08ba6fb5, 0x571be91f, 0xf296ec6b, 0x2a0dd915,
+			0xb6636521, 0xe7b9f9b6, 0xff34052e, 0xc5855664,
+		0x53b02d5d, 0xa99f8fa1, 0x08ba4799, 0x6e85076a},
+		{
+			0x4b7a70e9, 0xb5b32944, 0xdb75092e, 0xc4192623,
+			0xad6ea6b0, 0x49a7df7d, 0x9cee60b8, 0x8fedb266,
+			0xecaa8c71, 0x699a17ff, 0x5664526c, 0xc2b19ee1,
+			0x193602a5, 0x75094c29, 0xa0591340, 0xe4183a3e,
+			0x3f54989a, 0x5b429d65, 0x6b8fe4d6, 0x99f73fd6,
+			0xa1d29c07, 0xefe830f5, 0x4d2d38e6, 0xf0255dc1,
+			0x4cdd2086, 0x8470eb26, 0x6382e9c6, 0x021ecc5e,
+			0x09686b3f, 0x3ebaefc9, 0x3c971814, 0x6b6a70a1,
+			0x687f3584, 0x52a0e286, 0xb79c5305, 0xaa500737,
+			0x3e07841c, 0x7fdeae5c, 0x8e7d44ec, 0x5716f2b8,
+			0xb03ada37, 0xf0500c0d, 0xf01c1f04, 0x0200b3ff,
+			0xae0cf51a, 0x3cb574b2, 0x25837a58, 0xdc0921bd,
+			0xd19113f9, 0x7ca92ff6, 0x94324773, 0x22f54701,
+			0x3ae5e581, 0x37c2dadc, 0xc8b57634, 0x9af3dda7,
+			0xa9446146, 0x0fd0030e, 0xecc8c73e, 0xa4751e41,
+			0xe238cd99, 0x3bea0e2f, 0x3280bba1, 0x183eb331,
+			0x4e548b38, 0x4f6db908, 0x6f420d03, 0xf60a04bf,
+			0x2cb81290, 0x24977c79, 0x5679b072, 0xbcaf89af,
+			0xde9a771f, 0xd9930810, 0xb38bae12, 0xdccf3f2e,
+			0x5512721f, 0x2e6b7124, 0x501adde6, 0x9f84cd87,
+			0x7a584718, 0x7408da17, 0xbc9f9abc, 0xe94b7d8c,
+			0xec7aec3a, 0xdb851dfa, 0x63094366, 0xc464c3d2,
+			0xef1c1847, 0x3215d908, 0xdd433b37, 0x24c2ba16,
+			0x12a14d43, 0x2a65c451, 0x50940002, 0x133ae4dd,
+			0x71dff89e, 0x10314e55, 0x81ac77d6, 0x5f11199b,
+			0x043556f1, 0xd7a3c76b, 0x3c11183b, 0x5924a509,
+			0xf28fe6ed, 0x97f1fbfa, 0x9ebabf2c, 0x1e153c6e,
+			0x86e34570, 0xeae96fb1, 0x860e5e0a, 0x5a3e2ab3,
+			0x771fe71c, 0x4e3d06fa, 0x2965dcb9, 0x99e71d0f,
+			0x803e89d6, 0x5266c825, 0x2e4cc978, 0x9c10b36a,
+			0xc6150eba, 0x94e2ea78, 0xa5fc3c53, 0x1e0a2df4,
+			0xf2f74ea7, 0x361d2b3d, 0x1939260f, 0x19c27960,
+			0x5223a708, 0xf71312b6, 0xebadfe6e, 0xeac31f66,
+			0xe3bc4595, 0xa67bc883, 0xb17f37d1, 0x018cff28,
+			0xc332ddef, 0xbe6c5aa5, 0x65582185, 0x68ab9802,
+			0xeecea50f, 0xdb2f953b, 0x2aef7dad, 0x5b6e2f84,
+			0x1521b628, 0x29076170, 0xecdd4775, 0x619f1510,
+			0x13cca830, 0xeb61bd96, 0x0334fe1e, 0xaa0363cf,
+			0xb5735c90, 0x4c70a239, 0xd59e9e0b, 0xcbaade14,
+			0xeecc86bc, 0x60622ca7, 0x9cab5cab, 0xb2f3846e,
+			0x648b1eaf, 0x19bdf0ca, 0xa02369b9, 0x655abb50,
+			0x40685a32, 0x3c2ab4b3, 0x319ee9d5, 0xc021b8f7,
+			0x9b540b19, 0x875fa099, 0x95f7997e, 0x623d7da8,
+			0xf837889a, 0x97e32d77, 0x11ed935f, 0x16681281,
+			0x0e358829, 0xc7e61fd6, 0x96dedfa1, 0x7858ba99,
+			0x57f584a5, 0x1b227263, 0x9b83c3ff, 0x1ac24696,
+			0xcdb30aeb, 0x532e3054, 0x8fd948e4, 0x6dbc3128,
+			0x58ebf2ef, 0x34c6ffea, 0xfe28ed61, 0xee7c3c73,
+			0x5d4a14d9, 0xe864b7e3, 0x42105d14, 0x203e13e0,
+			0x45eee2b6, 0xa3aaabea, 0xdb6c4f15, 0xfacb4fd0,
+			0xc742f442, 0xef6abbb5, 0x654f3b1d, 0x41cd2105,
+			0xd81e799e, 0x86854dc7, 0xe44b476a, 0x3d816250,
+			0xcf62a1f2, 0x5b8d2646, 0xfc8883a0, 0xc1c7b6a3,
+			0x7f1524c3, 0x69cb7492, 0x47848a0b, 0x5692b285,
+			0x095bbf00, 0xad19489d, 0x1462b174, 0x23820e00,
+			0x58428d2a, 0x0c55f5ea, 0x1dadf43e, 0x233f7061,
+			0x3372f092, 0x8d937e41, 0xd65fecf1, 0x6c223bdb,
+			0x7cde3759, 0xcbee7460, 0x4085f2a7, 0xce77326e,
+			0xa6078084, 0x19f8509e, 0xe8efd855, 0x61d99735,
+			0xa969a7aa, 0xc50c06c2, 0x5a04abfc, 0x800bcadc,
+			0x9e447a2e, 0xc3453484, 0xfdd56705, 0x0e1e9ec9,
+			0xdb73dbd3, 0x105588cd, 0x675fda79, 0xe3674340,
+			0xc5c43465, 0x713e38d8, 0x3d28f89e, 0xf16dff20,
+		0x153e21e7, 0x8fb03d4a, 0xe6e39f2b, 0xdb83adf7},
+		{
+			0xe93d5a68, 0x948140f7, 0xf64c261c, 0x94692934,
+			0x411520f7, 0x7602d4f7, 0xbcf46b2e, 0xd4a20068,
+			0xd4082471, 0x3320f46a, 0x43b7d4b7, 0x500061af,
+			0x1e39f62e, 0x97244546, 0x14214f74, 0xbf8b8840,
+			0x4d95fc1d, 0x96b591af, 0x70f4ddd3, 0x66a02f45,
+			0xbfbc09ec, 0x03bd9785, 0x7fac6dd0, 0x31cb8504,
+			0x96eb27b3, 0x55fd3941, 0xda2547e6, 0xabca0a9a,
+			0x28507825, 0x530429f4, 0x0a2c86da, 0xe9b66dfb,
+			0x68dc1462, 0xd7486900, 0x680ec0a4, 0x27a18dee,
+			0x4f3ffea2, 0xe887ad8c, 0xb58ce006, 0x7af4d6b6,
+			0xaace1e7c, 0xd3375fec, 0xce78a399, 0x406b2a42,
+			0x20fe9e35, 0xd9f385b9, 0xee39d7ab, 0x3b124e8b,
+			0x1dc9faf7, 0x4b6d1856, 0x26a36631, 0xeae397b2,
+			0x3a6efa74, 0xdd5b4332, 0x6841e7f7, 0xca7820fb,
+			0xfb0af54e, 0xd8feb397, 0x454056ac, 0xba489527,
+			0x55533a3a, 0x20838d87, 0xfe6ba9b7, 0xd096954b,
+			0x55a867bc, 0xa1159a58, 0xcca92963, 0x99e1db33,
+			0xa62a4a56, 0x3f3125f9, 0x5ef47e1c, 0x9029317c,
+			0xfdf8e802, 0x04272f70, 0x80bb155c, 0x05282ce3,
+			0x95c11548, 0xe4c66d22, 0x48c1133f, 0xc70f86dc,
+			0x07f9c9ee, 0x41041f0f, 0x404779a4, 0x5d886e17,
+			0x325f51eb, 0xd59bc0d1, 0xf2bcc18f, 0x41113564,
+			0x257b7834, 0x602a9c60, 0xdff8e8a3, 0x1f636c1b,
+			0x0e12b4c2, 0x02e1329e, 0xaf664fd1, 0xcad18115,
+			0x6b2395e0, 0x333e92e1, 0x3b240b62, 0xeebeb922,
+			0x85b2a20e, 0xe6ba0d99, 0xde720c8c, 0x2da2f728,
+			0xd0127845, 0x95b794fd, 0x647d0862, 0xe7ccf5f0,
+			0x5449a36f, 0x877d48fa, 0xc39dfd27, 0xf33e8d1e,
+			0x0a476341, 0x992eff74, 0x3a6f6eab, 0xf4f8fd37,
+			0xa812dc60, 0xa1ebddf8, 0x991be14c, 0xdb6e6b0d,
+			0xc67b5510, 0x6d672c37, 0x2765d43b, 0xdcd0e804,
+			0xf1290dc7, 0xcc00ffa3, 0xb5390f92, 0x690fed0b,
+			0x667b9ffb, 0xcedb7d9c, 0xa091cf0b, 0xd9155ea3,
+			0xbb132f88, 0x515bad24, 0x7b9479bf, 0x763bd6eb,
+			0x37392eb3, 0xcc115979, 0x8026e297, 0xf42e312d,
+			0x6842ada7, 0xc66a2b3b, 0x12754ccc, 0x782ef11c,
+			0x6a124237, 0xb79251e7, 0x06a1bbe6, 0x4bfb6350,
+			0x1a6b1018, 0x11caedfa, 0x3d25bdd8, 0xe2e1c3c9,
+			0x44421659, 0x0a121386, 0xd90cec6e, 0xd5abea2a,
+			0x64af674e, 0xda86a85f, 0xbebfe988, 0x64e4c3fe,
+			0x9dbc8057, 0xf0f7c086, 0x60787bf8, 0x6003604d,
+			0xd1fd8346, 0xf6381fb0, 0x7745ae04, 0xd736fccc,
+			0x83426b33, 0xf01eab71, 0xb0804187, 0x3c005e5f,
+			0x77a057be, 0xbde8ae24, 0x55464299, 0xbf582e61,
+			0x4e58f48f, 0xf2ddfda2, 0xf474ef38, 0x8789bdc2,
+			0x5366f9c3, 0xc8b38e74, 0xb475f255, 0x46fcd9b9,
+			0x7aeb2661, 0x8b1ddf84, 0x846a0e79, 0x915f95e2,
+			0x466e598e, 0x20b45770, 0x8cd55591, 0xc902de4c,
+			0xb90bace1, 0xbb8205d0, 0x11a86248, 0x7574a99e,
+			0xb77f19b6, 0xe0a9dc09, 0x662d09a1, 0xc4324633,
+			0xe85a1f02, 0x09f0be8c, 0x4a99a025, 0x1d6efe10,
+			0x1ab93d1d, 0x0ba5a4df, 0xa186f20f, 0x2868f169,
+			0xdcb7da83, 0x573906fe, 0xa1e2ce9b, 0x4fcd7f52,
+			0x50115e01, 0xa70683fa, 0xa002b5c4, 0x0de6d027,
+			0x9af88c27, 0x773f8641, 0xc3604c06, 0x61a806b5,
+			0xf0177a28, 0xc0f586e0, 0x006058aa, 0x30dc7d62,
+			0x11e69ed7, 0x2338ea63, 0x53c2dd94, 0xc2c21634,
+			0xbbcbee56, 0x90bcb6de, 0xebfc7da1, 0xce591d76,
+			0x6f05e409, 0x4b7c0188, 0x39720a3d, 0x7c927c24,
+			0x86e3725f, 0x724d9db9, 0x1ac15bb4, 0xd39eb8fc,
+			0xed545578, 0x08fca5b5, 0xd83d7cd3, 0x4dad0fc4,
+			0x1e50ef5e, 0xb161e6f8, 0xa28514d9, 0x6c51133c,
+			0x6fd5c7e7, 0x56e14ec4, 0x362abfce, 0xddc6c837,
+		0xd79a3234, 0x92638212, 0x670efa8e, 0x406000e0},
+		{
+			0x3a39ce37, 0xd3faf5cf, 0xabc27737, 0x5ac52d1b,
+			0x5cb0679e, 0x4fa33742, 0xd3822740, 0x99bc9bbe,
+			0xd5118e9d, 0xbf0f7315, 0xd62d1c7e, 0xc700c47b,
+			0xb78c1b6b, 0x21a19045, 0xb26eb1be, 0x6a366eb4,
+			0x5748ab2f, 0xbc946e79, 0xc6a376d2, 0x6549c2c8,
+			0x530ff8ee, 0x468dde7d, 0xd5730a1d, 0x4cd04dc6,
+			0x2939bbdb, 0xa9ba4650, 0xac9526e8, 0xbe5ee304,
+			0xa1fad5f0, 0x6a2d519a, 0x63ef8ce2, 0x9a86ee22,
+			0xc089c2b8, 0x43242ef6, 0xa51e03aa, 0x9cf2d0a4,
+			0x83c061ba, 0x9be96a4d, 0x8fe51550, 0xba645bd6,
+			0x2826a2f9, 0xa73a3ae1, 0x4ba99586, 0xef5562e9,
+			0xc72fefd3, 0xf752f7da, 0x3f046f69, 0x77fa0a59,
+			0x80e4a915, 0x87b08601, 0x9b09e6ad, 0x3b3ee593,
+			0xe990fd5a, 0x9e34d797, 0x2cf0b7d9, 0x022b8b51,
+			0x96d5ac3a, 0x017da67d, 0xd1cf3ed6, 0x7c7d2d28,
+			0x1f9f25cf, 0xadf2b89b, 0x5ad6b472, 0x5a88f54c,
+			0xe029ac71, 0xe019a5e6, 0x47b0acfd, 0xed93fa9b,
+			0xe8d3c48d, 0x283b57cc, 0xf8d56629, 0x79132e28,
+			0x785f0191, 0xed756055, 0xf7960e44, 0xe3d35e8c,
+			0x15056dd4, 0x88f46dba, 0x03a16125, 0x0564f0bd,
+			0xc3eb9e15, 0x3c9057a2, 0x97271aec, 0xa93a072a,
+			0x1b3f6d9b, 0x1e6321f5, 0xf59c66fb, 0x26dcf319,
+			0x7533d928, 0xb155fdf5, 0x03563482, 0x8aba3cbb,
+			0x28517711, 0xc20ad9f8, 0xabcc5167, 0xccad925f,
+			0x4de81751, 0x3830dc8e, 0x379d5862, 0x9320f991,
+			0xea7a90c2, 0xfb3e7bce, 0x5121ce64, 0x774fbe32,
+			0xa8b6e37e, 0xc3293d46, 0x48de5369, 0x6413e680,
+			0xa2ae0810, 0xdd6db224, 0x69852dfd, 0x09072166,
+			0xb39a460a, 0x6445c0dd, 0x586cdecf, 0x1c20c8ae,
+			0x5bbef7dd, 0x1b588d40, 0xccd2017f, 0x6bb4e3bb,
+			0xdda26a7e, 0x3a59ff45, 0x3e350a44, 0xbcb4cdd5,
+			0x72eacea8, 0xfa6484bb, 0x8d6612ae, 0xbf3c6f47,
+			0xd29be463, 0x542f5d9e, 0xaec2771b, 0xf64e6370,
+			0x740e0d8d, 0xe75b1357, 0xf8721671, 0xaf537d5d,
+			0x4040cb08, 0x4eb4e2cc, 0x34d2466a, 0x0115af84,
+			0xe1b00428, 0x95983a1d, 0x06b89fb4, 0xce6ea048,
+			0x6f3f3b82, 0x3520ab82, 0x011a1d4b, 0x277227f8,
+			0x611560b1, 0xe7933fdc, 0xbb3a792b, 0x344525bd,
+			0xa08839e1, 0x51ce794b, 0x2f32c9b7, 0xa01fbac9,
+			0xe01cc87e, 0xbcc7d1f6, 0xcf0111c3, 0xa1e8aac7,
+			0x1a908749, 0xd44fbd9a, 0xd0dadecb, 0xd50ada38,
+			0x0339c32a, 0xc6913667, 0x8df9317c, 0xe0b12b4f,
+			0xf79e59b7, 0x43f5bb3a, 0xf2d519ff, 0x27d9459c,
+			0xbf97222c, 0x15e6fc2a, 0x0f91fc71, 0x9b941525,
+			0xfae59361, 0xceb69ceb, 0xc2a86459, 0x12baa8d1,
+			0xb6c1075e, 0xe3056a0c, 0x10d25065, 0xcb03a442,
+			0xe0ec6e0e, 0x1698db3b, 0x4c98a0be, 0x3278e964,
+			0x9f1f9532, 0xe0d392df, 0xd3a0342b, 0x8971f21e,
+			0x1b0a7441, 0x4ba3348c, 0xc5be7120, 0xc37632d8,
+			0xdf359f8d, 0x9b992f2e, 0xe60b6f47, 0x0fe3f11d,
+			0xe54cda54, 0x1edad891, 0xce6279cf, 0xcd3e7e6f,
+			0x1618b166, 0xfd2c1d05, 0x848fd2c5, 0xf6fb2299,
+			0xf523f357, 0xa6327623, 0x93a83531, 0x56cccd02,
+			0xacf08162, 0x5a75ebb5, 0x6e163697, 0x88d273cc,
+			0xde966292, 0x81b949d0, 0x4c50901b, 0x71c65614,
+			0xe6c6c7bd, 0x327a140a, 0x45e1d006, 0xc3f27b9a,
+			0xc9aa53fd, 0x62a80f00, 0xbb25bfe2, 0x35bdd2f6,
+			0x71126905, 0xb2040222, 0xb6cbcf7c, 0xcd769c2b,
+			0x53113ec0, 0x1640e3d3, 0x38abbd60, 0x2547adf0,
+			0xba38209c, 0xf746ce76, 0x77afa1c5, 0x20756060,
+			0x85cbfe4e, 0x8ae88dd8, 0x7aaaf9b0, 0x4cf9aa7e,
+			0x1948c25c, 0x02fb8a8c, 0x01c36ae4, 0xd6ebe1f9,
+			0x90d4f869, 0xa65cdea0, 0x3f09252d, 0xc208e69f,
+		0xb74e6132, 0xce77e25b, 0x578fdfe3, 0x3ac372e6}
+	},
+	{
+		0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344,
+		0xa4093822, 0x299f31d0, 0x082efa98, 0xec4e6c89,
+		0x452821e6, 0x38d01377, 0xbe5466cf, 0x34e90c6c,
+		0xc0ac29b7, 0xc97c50dd, 0x3f84d5b5, 0xb5470917,
+		0x9216d5d9, 0x8979fb1b
+	} };
+
+	*c = initstate;
+}
+
+u_int32_t
+Blowfish_stream2word(const u_int8_t *data, u_int16_t databytes,
+    u_int16_t *current)
+{
+	u_int8_t i;
+	u_int16_t j;
+	u_int32_t temp;
+
+	temp = 0x00000000;
+	j = *current;
+
+	for (i = 0; i < 4; i++, j++) {
+		if (j >= databytes)
+			j = 0;
+		temp = (temp << 8) | data[j];
+	}
+
+	*current = j;
+	return temp;
+}
+
+void
+Blowfish_expand0state(blf_ctx *c, const u_int8_t *key, u_int16_t keybytes)
+{
+	u_int16_t i;
+	u_int16_t j;
+	u_int16_t k;
+	u_int32_t temp;
+	u_int32_t datal;
+	u_int32_t datar;
+
+	j = 0;
+	for (i = 0; i < BLF_N + 2; i++) {
+		/* Extract 4 int8 to 1 int32 from keystream */
+		temp = Blowfish_stream2word(key, keybytes, &j);
+		c->P[i] = c->P[i] ^ temp;
+	}
+
+	j = 0;
+	datal = 0x00000000;
+	datar = 0x00000000;
+	for (i = 0; i < BLF_N + 2; i += 2) {
+		Blowfish_encipher(c, &datal, &datar);
+
+		c->P[i] = datal;
+		c->P[i + 1] = datar;
+	}
+
+	for (i = 0; i < 4; i++) {
+		for (k = 0; k < 256; k += 2) {
+			Blowfish_encipher(c, &datal, &datar);
+
+			c->S[i][k] = datal;
+			c->S[i][k + 1] = datar;
+		}
+	}
+}
+
+
+void
+Blowfish_expandstate(blf_ctx *c, const u_int8_t *data, u_int16_t databytes,
+    const u_int8_t *key, u_int16_t keybytes)
+{
+	u_int16_t i;
+	u_int16_t j;
+	u_int16_t k;
+	u_int32_t temp;
+	u_int32_t datal;
+	u_int32_t datar;
+
+	j = 0;
+	for (i = 0; i < BLF_N + 2; i++) {
+		/* Extract 4 int8 to 1 int32 from keystream */
+		temp = Blowfish_stream2word(key, keybytes, &j);
+		c->P[i] = c->P[i] ^ temp;
+	}
+
+	j = 0;
+	datal = 0x00000000;
+	datar = 0x00000000;
+	for (i = 0; i < BLF_N + 2; i += 2) {
+		datal ^= Blowfish_stream2word(data, databytes, &j);
+		datar ^= Blowfish_stream2word(data, databytes, &j);
+		Blowfish_encipher(c, &datal, &datar);
+
+		c->P[i] = datal;
+		c->P[i + 1] = datar;
+	}
+
+	for (i = 0; i < 4; i++) {
+		for (k = 0; k < 256; k += 2) {
+			datal ^= Blowfish_stream2word(data, databytes, &j);
+			datar ^= Blowfish_stream2word(data, databytes, &j);
+			Blowfish_encipher(c, &datal, &datar);
+
+			c->S[i][k] = datal;
+			c->S[i][k + 1] = datar;
+		}
+	}
+
+}
+
+void
+blf_key(blf_ctx *c, const u_int8_t *k, u_int16_t len)
+{
+	/* Initialize S-boxes and subkeys with Pi */
+	Blowfish_initstate(c);
+
+	/* Transform S-boxes and subkeys with key */
+	Blowfish_expand0state(c, k, len);
+}
+
+void
+blf_enc(blf_ctx *c, u_int32_t *data, u_int16_t blocks)
+{
+	u_int32_t *d;
+	u_int16_t i;
+
+	d = data;
+	for (i = 0; i < blocks; i++) {
+		Blowfish_encipher(c, d, d + 1);
+		d += 2;
+	}
+}
+
+void
+blf_dec(blf_ctx *c, u_int32_t *data, u_int16_t blocks)
+{
+	u_int32_t *d;
+	u_int16_t i;
+
+	d = data;
+	for (i = 0; i < blocks; i++) {
+		Blowfish_decipher(c, d, d + 1);
+		d += 2;
+	}
+}
+
+void
+blf_ecb_encrypt(blf_ctx *c, u_int8_t *data, u_int32_t len)
+{
+	u_int32_t l, r;
+	u_int32_t i;
+
+	for (i = 0; i < len; i += 8) {
+		l = data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3];
+		r = data[4] << 24 | data[5] << 16 | data[6] << 8 | data[7];
+		Blowfish_encipher(c, &l, &r);
+		data[0] = l >> 24 & 0xff;
+		data[1] = l >> 16 & 0xff;
+		data[2] = l >> 8 & 0xff;
+		data[3] = l & 0xff;
+		data[4] = r >> 24 & 0xff;
+		data[5] = r >> 16 & 0xff;
+		data[6] = r >> 8 & 0xff;
+		data[7] = r & 0xff;
+		data += 8;
+	}
+}
+
+void
+blf_ecb_decrypt(blf_ctx *c, u_int8_t *data, u_int32_t len)
+{
+	u_int32_t l, r;
+	u_int32_t i;
+
+	for (i = 0; i < len; i += 8) {
+		l = data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3];
+		r = data[4] << 24 | data[5] << 16 | data[6] << 8 | data[7];
+		Blowfish_decipher(c, &l, &r);
+		data[0] = l >> 24 & 0xff;
+		data[1] = l >> 16 & 0xff;
+		data[2] = l >> 8 & 0xff;
+		data[3] = l & 0xff;
+		data[4] = r >> 24 & 0xff;
+		data[5] = r >> 16 & 0xff;
+		data[6] = r >> 8 & 0xff;
+		data[7] = r & 0xff;
+		data += 8;
+	}
+}
+
+void
+blf_cbc_encrypt(blf_ctx *c, u_int8_t *iv, u_int8_t *data, u_int32_t len)
+{
+	u_int32_t l, r;
+	u_int32_t i, j;
+
+	for (i = 0; i < len; i += 8) {
+		for (j = 0; j < 8; j++)
+			data[j] ^= iv[j];
+		l = data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3];
+		r = data[4] << 24 | data[5] << 16 | data[6] << 8 | data[7];
+		Blowfish_encipher(c, &l, &r);
+		data[0] = l >> 24 & 0xff;
+		data[1] = l >> 16 & 0xff;
+		data[2] = l >> 8 & 0xff;
+		data[3] = l & 0xff;
+		data[4] = r >> 24 & 0xff;
+		data[5] = r >> 16 & 0xff;
+		data[6] = r >> 8 & 0xff;
+		data[7] = r & 0xff;
+		iv = data;
+		data += 8;
+	}
+}
+
+void
+blf_cbc_decrypt(blf_ctx *c, u_int8_t *iva, u_int8_t *data, u_int32_t len)
+{
+	u_int32_t l, r;
+	u_int8_t *iv;
+	u_int32_t i, j;
+
+	iv = data + len - 16;
+	data = data + len - 8;
+	for (i = len - 8; i >= 8; i -= 8) {
+		l = data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3];
+		r = data[4] << 24 | data[5] << 16 | data[6] << 8 | data[7];
+		Blowfish_decipher(c, &l, &r);
+		data[0] = l >> 24 & 0xff;
+		data[1] = l >> 16 & 0xff;
+		data[2] = l >> 8 & 0xff;
+		data[3] = l & 0xff;
+		data[4] = r >> 24 & 0xff;
+		data[5] = r >> 16 & 0xff;
+		data[6] = r >> 8 & 0xff;
+		data[7] = r & 0xff;
+		for (j = 0; j < 8; j++)
+			data[j] ^= iv[j];
+		iv -= 8;
+		data -= 8;
+	}
+	l = data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3];
+	r = data[4] << 24 | data[5] << 16 | data[6] << 8 | data[7];
+	Blowfish_decipher(c, &l, &r);
+	data[0] = l >> 24 & 0xff;
+	data[1] = l >> 16 & 0xff;
+	data[2] = l >> 8 & 0xff;
+	data[3] = l & 0xff;
+	data[4] = r >> 24 & 0xff;
+	data[5] = r >> 16 & 0xff;
+	data[6] = r >> 8 & 0xff;
+	data[7] = r & 0xff;
+	for (j = 0; j < 8; j++)
+		data[j] ^= iva[j];
+}
+
+#if 0
+void
+report(u_int32_t data[], u_int16_t len)
+{
+	u_int16_t i;
+	for (i = 0; i < len; i += 2)
+		printf("Block %0hd: %08lx %08lx.\n",
+		    i / 2, data[i], data[i + 1]);
+}
+void
+main(void)
+{
+
+	blf_ctx c;
+	char    key[] = "AAAAA";
+	char    key2[] = "abcdefghijklmnopqrstuvwxyz";
+
+	u_int32_t data[10];
+	u_int32_t data2[] =
+	{0x424c4f57l, 0x46495348l};
+
+	u_int16_t i;
+
+	/* First test */
+	for (i = 0; i < 10; i++)
+		data[i] = i;
+
+	blf_key(&c, (u_int8_t *) key, 5);
+	blf_enc(&c, data, 5);
+	blf_dec(&c, data, 1);
+	blf_dec(&c, data + 2, 4);
+	printf("Should read as 0 - 9.\n");
+	report(data, 10);
+
+	/* Second test */
+	blf_key(&c, (u_int8_t *) key2, strlen(key2));
+	blf_enc(&c, data2, 1);
+	printf("\nShould read as: 0x324ed0fe 0xf413a203.\n");
+	report(data2, 2);
+	blf_dec(&c, data2, 1);
+	report(data2, 2);
+}
+#endif
diff --git a/server/node_modules/bcrypt/src/node_blf.h b/server/node_modules/bcrypt/src/node_blf.h
new file mode 100644
index 0000000..2d50a39
--- /dev/null
+++ b/server/node_modules/bcrypt/src/node_blf.h
@@ -0,0 +1,132 @@
+/* $OpenBSD: blf.h,v 1.7 2007/03/14 17:59:41 grunk Exp $ */
+/*
+ * Blowfish - a fast block cipher designed by Bruce Schneier
+ *
+ * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed by Niels Provos.
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _NODE_BLF_H_
+#define _NODE_BLF_H_
+
+#include <sys/types.h>
+
+/* Solaris compatibility */
+#ifdef __sun
+#define u_int8_t uint8_t
+#define u_int16_t uint16_t
+#define u_int32_t uint32_t
+#define u_int64_t uint64_t
+#endif
+
+#ifdef _WIN32
+#define u_int8_t unsigned __int8
+#define u_int16_t unsigned __int16
+#define u_int32_t unsigned __int32
+#define u_int64_t unsigned __int64
+#endif
+
+/* Windows ssize_t compatibility */
+#if defined(_WIN32) || defined(_WIN64)
+#  if defined(_WIN64)
+     typedef __int64 LONG_PTR;
+#  else
+     typedef long LONG_PTR;
+#  endif
+  typedef LONG_PTR SSIZE_T;
+  typedef SSIZE_T ssize_t;
+#endif
+
+/* z/OS compatibility */
+#ifdef __MVS__
+typedef unsigned char u_int8_t;
+typedef unsigned short u_int16_t;
+typedef unsigned int u_int32_t;
+typedef unsigned long long u_int64_t;
+#endif
+
+#define BCRYPT_VERSION '2'
+#define BCRYPT_MAXSALT 16	/* Precomputation is just so nice */
+#define BCRYPT_BLOCKS 6		/* Ciphertext blocks */
+#define BCRYPT_MINROUNDS 16	/* we have log2(rounds) in salt */
+
+/* Schneier specifies a maximum key length of 56 bytes.
+ * This ensures that every key bit affects every cipher
+ * bit.  However, the subkeys can hold up to 72 bytes.
+ * Warning: For normal blowfish encryption only 56 bytes
+ * of the key affect all cipherbits.
+ */
+
+#define BLF_N	16			/* Number of Subkeys */
+#define BLF_MAXKEYLEN ((BLF_N-2)*4)	/* 448 bits */
+#define BLF_MAXUTILIZED ((BLF_N+2)*4)	/* 576 bits */
+
+#define _PASSWORD_LEN   128             /* max length, not counting NUL */
+#define _SALT_LEN       32              /* max length */
+
+/* Blowfish context */
+typedef struct BlowfishContext {
+	u_int32_t S[4][256];	/* S-Boxes */
+	u_int32_t P[BLF_N + 2];	/* Subkeys */
+} blf_ctx;
+
+/* Raw access to customized Blowfish
+ *	blf_key is just:
+ *	Blowfish_initstate( state )
+ *	Blowfish_expand0state( state, key, keylen )
+ */
+
+void Blowfish_encipher(blf_ctx *, u_int32_t *, u_int32_t *);
+void Blowfish_decipher(blf_ctx *, u_int32_t *, u_int32_t *);
+void Blowfish_initstate(blf_ctx *);
+void Blowfish_expand0state(blf_ctx *, const u_int8_t *, u_int16_t);
+void Blowfish_expandstate
+(blf_ctx *, const u_int8_t *, u_int16_t, const u_int8_t *, u_int16_t);
+
+/* Standard Blowfish */
+
+void blf_key(blf_ctx *, const u_int8_t *, u_int16_t);
+void blf_enc(blf_ctx *, u_int32_t *, u_int16_t);
+void blf_dec(blf_ctx *, u_int32_t *, u_int16_t);
+
+void blf_ecb_encrypt(blf_ctx *, u_int8_t *, u_int32_t);
+void blf_ecb_decrypt(blf_ctx *, u_int8_t *, u_int32_t);
+
+void blf_cbc_encrypt(blf_ctx *, u_int8_t *, u_int8_t *, u_int32_t);
+void blf_cbc_decrypt(blf_ctx *, u_int8_t *, u_int8_t *, u_int32_t);
+
+/* Converts u_int8_t to u_int32_t */
+u_int32_t Blowfish_stream2word(const u_int8_t *, u_int16_t , u_int16_t *);
+
+/* bcrypt functions*/
+void bcrypt_gensalt(char, u_int8_t, u_int8_t*, char *);
+void bcrypt(const char *, size_t key_len, const char *, char *);
+void encode_salt(char *, u_int8_t *, char, u_int16_t, u_int8_t);
+u_int32_t bcrypt_get_rounds(const char *);
+
+#endif
diff --git a/server/node_modules/bcrypt/test/async.test.js b/server/node_modules/bcrypt/test/async.test.js
new file mode 100644
index 0000000..fb59367
--- /dev/null
+++ b/server/node_modules/bcrypt/test/async.test.js
@@ -0,0 +1,209 @@
+const bcrypt = require('../bcrypt');
+
+test('salt_length', done => {
+    expect.assertions(1);
+    bcrypt.genSalt(10, function (err, salt) {
+        expect(salt).toHaveLength(29);
+        done();
+    });
+})
+
+test('salt_only_cb', () => {
+    expect.assertions(1);
+    expect(() => {
+        bcrypt.genSalt((err, salt) => {
+        });
+    }).not.toThrow();
+})
+
+test('salt_rounds_is_string_number', done => {
+    expect.assertions(2);
+    bcrypt.genSalt('10', void 0, function (err, salt) {
+        expect(err instanceof Error).toBe(true)
+        expect(err.message).toBe('rounds must be a number')
+        done();
+    });
+})
+
+test('salt_rounds_is_string_non_number', done => {
+    expect.assertions(2);
+    bcrypt.genSalt('z', function (err, salt) {
+        expect(err instanceof Error).toBe(true)
+        expect(err.message).toBe('rounds must be a number')
+        done();
+    });
+})
+
+test('salt_minor', done => {
+    expect.assertions(3);
+    bcrypt.genSalt(10, 'a', function (err, value) {
+        expect(value).toHaveLength(29);
+        const [_, minor, salt] = value.split('$');
+        expect(minor).toEqual('2a');
+        expect(salt).toEqual('10');
+        done();
+    });
+})
+
+test('salt_minor_b', done => {
+    expect.assertions(3);
+    bcrypt.genSalt(10, 'b', function (err, value) {
+        expect(value).toHaveLength(29);
+        const [_, minor, salt] = value.split('$');
+        expect(minor).toEqual('2b');
+        expect(salt).toEqual('10');
+        done();
+    });
+})
+
+test('hash', done => {
+    expect.assertions(2);
+    bcrypt.genSalt(10, function (err, salt) {
+        bcrypt.hash('password', salt, function (err, res) {
+            expect(res).toBeDefined();
+            expect(err).toBeUndefined();
+            done();
+        });
+    });
+})
+
+test('hash_rounds', done => {
+    expect.assertions(1);
+    bcrypt.hash('bacon', 8, function (err, hash) {
+        expect(bcrypt.getRounds(hash)).toEqual(8);
+        done();
+    });
+})
+
+test('hash_empty_strings', done => {
+    expect.assertions(1);
+    bcrypt.genSalt(10, function (err, salt) {
+        bcrypt.hash('', salt, function (err, res) {
+            expect(res).toBeDefined();
+            done();
+        });
+    });
+})
+
+test('hash_fails_with_empty_salt', done => {
+    expect.assertions(1);
+    bcrypt.hash('', '', function (err, res) {
+        expect(err.message).toBe('Invalid salt. Salt must be in the form of: $Vers$log2(NumRounds)$saltvalue')
+        done();
+    });
+})
+
+test('hash_no_params', done => {
+    expect.assertions(1);
+    bcrypt.hash(function (err, hash) {
+        expect(err.message).toBe('data must be a string or Buffer and salt must either be a salt string or a number of rounds')
+        done();
+    });
+})
+
+test('hash_one_param', done => {
+    expect.assertions(1);
+    bcrypt.hash('password', function (err, hash) {
+        expect(err.message).toBe('data must be a string or Buffer and salt must either be a salt string or a number of rounds');
+        done();
+    });
+})
+
+test('hash_salt_validity', done => {
+    expect.assertions(2);
+    bcrypt.hash('password', '$2a$10$somesaltyvaluertsetrse', function (err, enc) {
+        expect(err).toBeUndefined();
+        bcrypt.hash('password', 'some$value', function (err, enc) {
+            expect(err.message).toBe("Invalid salt. Salt must be in the form of: $Vers$log2(NumRounds)$saltvalue");
+            done();
+        });
+    });
+})
+
+test('verify_salt', done => {
+    expect.assertions(2);
+    bcrypt.genSalt(10, function (err, value) {
+        const [_, version, rounds] = value.split('$');
+        expect(version).toEqual('2b');
+        expect(rounds).toEqual('10');
+        done();
+    });
+})
+
+test('verify_salt_min_rounds', done => {
+    expect.assertions(2);
+    bcrypt.genSalt(1, function (err, value) {
+        const [_, version, rounds] = value.split('$');
+        expect(version).toEqual('2b');
+        expect(rounds).toEqual('04');
+        done();
+    });
+})
+
+test('verify_salt_max_rounds', done => {
+    expect.assertions(2);
+    bcrypt.genSalt(100, function (err, value) {
+        const [_, version, rounds] = value.split('$');
+        expect(version).toEqual('2b');
+        expect(rounds).toEqual('31');
+        done();
+    });
+})
+
+test('hash_compare', done => {
+    expect.assertions(2);
+    bcrypt.genSalt(10, function (err, salt) {
+        bcrypt.hash("test", salt, function (err, hash) {
+            bcrypt.compare("test", hash, function (err, res) {
+                expect(hash).toBeDefined();
+                bcrypt.compare("blah", hash, function (err, res) {
+                    expect(res).toBe(false);
+                    done();
+                });
+            });
+        });
+    });
+})
+
+test('hash_compare_empty_strings', done => {
+    expect.assertions(2);
+    const hash = bcrypt.hashSync("test", bcrypt.genSaltSync(10));
+
+    bcrypt.compare("", hash, function (err, res) {
+        expect(res).toEqual(false)
+        bcrypt.compare("", "", function (err, res) {
+            expect(res).toEqual(false);
+            done();
+        });
+    });
+})
+
+test('hash_compare_invalid_strings', done => {
+    expect.assertions(2);
+    const fullString = 'envy1362987212538';
+    const hash = '$2a$10$XOPbrlUPQdwdJUpSrIF6X.LbE14qsMmKGhM1A8W9iqaG3vv1BD7WC';
+    const wut = ':';
+    bcrypt.compare(fullString, hash, function (err, res) {
+        expect(res).toBe(true);
+        bcrypt.compare(fullString, wut, function (err, res) {
+            expect(res).toBe(false);
+            done();
+        });
+    });
+})
+
+test('compare_no_params', done => {
+    expect.assertions(1);
+    bcrypt.compare(function (err, hash) {
+        expect(err.message).toBe('data and hash arguments required');
+        done();
+    });
+})
+
+test('hash_compare_one_param', done => {
+    expect.assertions(1);
+    bcrypt.compare('password', function (err, hash) {
+        expect(err.message).toBe('data and hash arguments required');
+        done();
+    });
+})
diff --git a/server/node_modules/bcrypt/test/implementation.test.js b/server/node_modules/bcrypt/test/implementation.test.js
new file mode 100644
index 0000000..647f32a
--- /dev/null
+++ b/server/node_modules/bcrypt/test/implementation.test.js
@@ -0,0 +1,48 @@
+const bcrypt = require('../bcrypt');
+
+// some tests were adapted from https://github.com/riverrun/bcrypt_elixir/blob/master/test/base_test.exs
+// which are under the BSD LICENSE
+
+test('openwall', () => {
+    expect(bcrypt.hashSync("U*U", "$2a$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2a$05$CCCCCCCCCCCCCCCCCCCCC.E5YPO9kmyuRGyh0XouQYb4YMJKvyOeW");
+    expect(bcrypt.hashSync("U*U*", "$2a$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2a$05$CCCCCCCCCCCCCCCCCCCCC.VGOzA784oUp/Z0DY336zx7pLYAy0lwK");
+    expect(bcrypt.hashSync("U*U*U", "$2a$05$XXXXXXXXXXXXXXXXXXXXXO")).toStrictEqual("$2a$05$XXXXXXXXXXXXXXXXXXXXXOAcXxm9kjPGEMsLznoKqmqw7tc8WCx4a");
+    expect(bcrypt.hashSync("", "$2a$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2a$05$CCCCCCCCCCCCCCCCCCCCC.7uG0VCzI2bS7j6ymqJi9CdcdxiRTWNy");
+    expect(bcrypt.hashSync("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789", "$2a$05$abcdefghijklmnopqrstuu")).toStrictEqual("$2a$05$abcdefghijklmnopqrstuu5s2v8.iXieOjg/.AySBTTZIIVFJeBui");
+})
+
+test('openbsd', () => {
+    expect(bcrypt.hashSync("000000000000000000000000000000000000000000000000000000000000000000000000", "$2a$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2a$05$CCCCCCCCCCCCCCCCCCCCC.6.O1dLNbjod2uo0DVcW.jHucKbPDdHS")
+    expect(bcrypt.hashSync("000000000000000000000000000000000000000000000000000000000000000000000000", "$2b$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2b$05$CCCCCCCCCCCCCCCCCCCCC.6.O1dLNbjod2uo0DVcW.jHucKbPDdHS")
+})
+
+test('long_passwords', () => {
+    // bcrypt wrap-around bug in $2a$
+    expect(bcrypt.hashSync("012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234", "$2a$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2a$05$CCCCCCCCCCCCCCCCCCCCC.6.O1dLNbjod2uo0DVcW.jHucKbPDdHS")
+    expect(bcrypt.hashSync("01XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX", "$2a$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2a$05$CCCCCCCCCCCCCCCCCCCCC.6.O1dLNbjod2uo0DVcW.jHucKbPDdHS")
+
+    // tests for $2b$ which fixes wrap-around bugs
+    expect(bcrypt.hashSync("012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234", "$2b$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2b$05$CCCCCCCCCCCCCCCCCCCCC.XxrQqgBi/5Sxuq9soXzDtjIZ7w5pMfK")
+    expect(bcrypt.hashSync("0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345", "$2b$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2b$05$CCCCCCCCCCCCCCCCCCCCC.XxrQqgBi/5Sxuq9soXzDtjIZ7w5pMfK")
+})
+
+test('embedded_nulls', () => {
+    expect(bcrypt.hashSync("Passw\0rd123", "$2b$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2b$05$CCCCCCCCCCCCCCCCCCCCC.VHy/kzL4sCcX3Ib3wN5rNGiRt.TpfxS")
+    expect(bcrypt.hashSync("Passw\0 you can literally write anything after the NUL character", "$2b$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2b$05$CCCCCCCCCCCCCCCCCCCCC.4vJLJQ6nZ/70INTjjSZWQ0iyUek92tu")
+    expect(bcrypt.hashSync(Buffer.from("Passw\0 you can literally write anything after the NUL character"), "$2b$05$CCCCCCCCCCCCCCCCCCCCC.")).toStrictEqual("$2b$05$CCCCCCCCCCCCCCCCCCCCC.4vJLJQ6nZ/70INTjjSZWQ0iyUek92tu")
+})
+
+test('shorten_salt_to_128_bits', () => {
+    expect(bcrypt.hashSync("test", "$2a$10$1234567899123456789012")).toStrictEqual("$2a$10$123456789912345678901u.OtL1A1eGK5wmvBKUDYKvuVKI7h2XBu")
+    expect(bcrypt.hashSync("U*U*", "$2a$05$CCCCCCCCCCCCCCCCCCCCCh")).toStrictEqual("$2a$05$CCCCCCCCCCCCCCCCCCCCCeUQ7VjYZ2hd4bLYZdhuPpZMUpEUJDw1S")
+    expect(bcrypt.hashSync("U*U*", "$2a$05$CCCCCCCCCCCCCCCCCCCCCM")).toStrictEqual("$2a$05$CCCCCCCCCCCCCCCCCCCCC.VGOzA784oUp/Z0DY336zx7pLYAy0lwK")
+    expect(bcrypt.hashSync("U*U*", "$2a$05$CCCCCCCCCCCCCCCCCCCCCA")).toStrictEqual("$2a$05$CCCCCCCCCCCCCCCCCCCCC.VGOzA784oUp/Z0DY336zx7pLYAy0lwK")
+})
+
+test('consistency', () => {
+    expect(bcrypt.hashSync("ππππππππ", "$2a$10$.TtQJ4Jr6isd4Hp.mVfZeu")).toStrictEqual("$2a$10$.TtQJ4Jr6isd4Hp.mVfZeuh6Gws4rOQ/vdBczhDx.19NFK0Y84Dle")
+    expect(bcrypt.hashSync("p@5sw0rd", "$2b$12$zQ4CooEXdGqcwi0PHsgc8e")).toStrictEqual("$2b$12$zQ4CooEXdGqcwi0PHsgc8eAf0DLXE/XHoBE8kCSGQ97rXwuClaPam")
+    expect(bcrypt.hashSync("C'est bon, la vie!", "$2b$12$cbo7LZ.wxgW4yxAA5Vqlv.")).toStrictEqual("$2b$12$cbo7LZ.wxgW4yxAA5Vqlv.KR6QFPt4qCdc9RYJNXxa/rbUOp.1sw.")
+    expect(bcrypt.hashSync("ἓν οἶδα ὅτι οὐδὲν οἶδα", "$2b$12$LeHKWR2bmrazi/6P22Jpau")).toStrictEqual("$2b$12$LeHKWR2bmrazi/6P22JpauX5my/eKwwKpWqL7L5iEByBnxNc76FRW")
+    expect(bcrypt.hashSync(Buffer.from("ἓν οἶδα ὅτι οὐδὲν οἶδα"), "$2b$12$LeHKWR2bmrazi/6P22Jpau")).toStrictEqual("$2b$12$LeHKWR2bmrazi/6P22JpauX5my/eKwwKpWqL7L5iEByBnxNc76FRW")
+})
diff --git a/server/node_modules/bcrypt/test/promise.test.js b/server/node_modules/bcrypt/test/promise.test.js
new file mode 100644
index 0000000..0103418
--- /dev/null
+++ b/server/node_modules/bcrypt/test/promise.test.js
@@ -0,0 +1,168 @@
+const bcrypt = require('../bcrypt');
+const promises = require('../promises');
+
+test('salt_returns_promise_on_no_args', () => {
+    // make sure test passes with non-native implementations such as bluebird
+    // http://stackoverflow.com/questions/27746304/how-do-i-tell-if-an-object-is-a-promise
+    expect(typeof bcrypt.genSalt().then).toEqual('function')
+})
+
+test('salt_returns_promise_on_null_callback', () => {
+    expect(typeof bcrypt.genSalt(13, null, null).then).toEqual('function')
+})
+
+test('salt_length', () => {
+    return expect(bcrypt.genSalt(10)).resolves.toHaveLength(29);
+})
+
+test('salt_rounds_is_string_number', () => {
+    return expect(bcrypt.genSalt('10')).rejects.toThrow('rounds must be a number');
+})
+
+test('salt_rounds_is_string_non_number', () => {
+    return expect(bcrypt.genSalt('b')).rejects.toThrow('rounds must be a number');
+})
+
+test('hash_returns_promise_on_null_callback', () => {
+    expect(typeof bcrypt.hash('password', 10, null).then).toStrictEqual('function')
+})
+
+test('hash', () => {
+    return expect(bcrypt.genSalt(10)
+        .then(salt => bcrypt.hash('password', salt))).resolves.toBeDefined()
+})
+
+test('hash_rounds', () => {
+    return bcrypt.hash('bacon', 8).then(hash => {
+        expect(bcrypt.getRounds(hash)).toStrictEqual(8)
+    });
+})
+
+test('hash_empty_strings', () => {
+    expect.assertions(2);
+    return Promise.all([
+        expect(bcrypt.genSalt(10)
+            .then(salt => bcrypt.hash('', salt)))
+            .resolves.toBeDefined(),
+        expect(bcrypt.hash('', '')).rejects.toThrow(''),
+    ]);
+})
+
+test('hash_no_params', () => {
+    expect.assertions(1);
+    return expect(bcrypt.hash()).rejects.toThrow('data and salt arguments required');
+})
+
+test('hash_one_param', () => {
+    return expect(bcrypt.hash('password')).rejects.toThrow('data and salt arguments required');
+})
+
+test('hash_salt_validity', () => {
+    expect.assertions(2);
+    return Promise.all(
+        [
+            expect(bcrypt.hash('password', '$2a$10$somesaltyvaluertsetrse')).resolves.toBeDefined(),
+            expect(bcrypt.hash('password', 'some$value')).rejects.toThrow("Invalid salt. Salt must be in the form of: $Vers$log2(NumRounds)$saltvalue")
+        ]);
+})
+
+test('verify_salt', () => {
+    expect.assertions(2);
+    return bcrypt.genSalt(10).then(result => {
+        const [_, version, salt] = result.split('$');
+        expect(version).toEqual('2b')
+        expect(salt).toEqual('10')
+    });
+})
+
+test('verify_salt_min_rounds', () => {
+    expect.assertions(2);
+    return bcrypt.genSalt(1).then(value => {
+        const [_, version, rounds] = value.split('$');
+        expect(version).toEqual('2b');
+        expect(rounds).toEqual('04');
+    });
+})
+
+test('verify_salt_max_rounds', () => {
+    expect.assertions(2);
+    return bcrypt.genSalt(100).then(value => {
+        const [_, version, rounds] = value.split('$');
+        expect(version).toEqual('2b');
+        expect(rounds).toEqual('31');
+    });
+})
+
+test('hash_compare_returns_promise_on_null_callback', () => {
+    expect(typeof bcrypt.compare('password', 'something', null).then).toStrictEqual('function')
+})
+
+test('hash_compare', () => {
+    expect.assertions(3);
+    return bcrypt.genSalt(10).then(function (salt) {
+        expect(salt).toHaveLength(29);
+        return bcrypt.hash("test", salt);
+    }).then(hash => Promise.all(
+        [
+            expect(bcrypt.compare("test", hash)).resolves.toEqual(true),
+            expect(bcrypt.compare("blah", hash)).resolves.toEqual(false)
+        ]));
+})
+
+test('hash_compare_empty_strings', () => {
+    expect.assertions(2);
+    const hash = bcrypt.hashSync("test", bcrypt.genSaltSync(10));
+    return Promise.all([
+        expect(bcrypt.compare("", hash)).resolves.toEqual(false),
+        expect(bcrypt.compare("", "")).resolves.toEqual(false)
+    ]);
+})
+
+test('hash_compare_invalid_strings', () => {
+    const fullString = 'envy1362987212538';
+    const hash = '$2a$10$XOPbrlUPQdwdJUpSrIF6X.LbE14qsMmKGhM1A8W9iqaG3vv1BD7WC';
+    const wut = ':';
+    return Promise.all([
+        expect(bcrypt.compare(fullString, hash)).resolves.toEqual(true),
+        expect(bcrypt.compare(fullString, wut)).resolves.toEqual(false),
+    ]);
+})
+
+test('hash_compare_no_params', () => {
+    expect.assertions(1);
+    return expect(bcrypt.compare()).rejects.toThrow('data and hash arguments required')
+})
+
+test('hash_compare_one_param', () => {
+    expect.assertions(1);
+    return expect(bcrypt.compare('password')).rejects.toThrow('data and hash arguments required')
+})
+
+test('change_promise_impl_reject', () => {
+
+    promises.use({
+        reject: function () {
+            return 'mock';
+        }
+    });
+
+    expect(promises.reject()).toEqual('mock');
+
+    // need to reset the promise implementation because of require cache
+    promises.use(global.Promise);
+})
+
+test('change_promise_impl_promise', () => {
+
+    promises.use({
+        reject: function (err) {
+            expect(err.message).toEqual('fn must be a function');
+            return 'mock';
+        }
+    });
+
+    expect(promises.promise('', '', '')).toEqual('mock');
+
+    // need to reset the promise implementation because of require cache
+    promises.use(global.Promise);
+})
diff --git a/server/node_modules/bcrypt/test/repetitions.test.js b/server/node_modules/bcrypt/test/repetitions.test.js
new file mode 100644
index 0000000..63ff407
--- /dev/null
+++ b/server/node_modules/bcrypt/test/repetitions.test.js
@@ -0,0 +1,55 @@
+const bcrypt = require('../bcrypt');
+
+const EXPECTED = 2500; //number of times to iterate these tests.)
+const { TEST_TIMEOUT_SECONDS } = process.env;
+let timeout = 5e3; // default test timeout
+
+// it is necessary to increase the test timeout when emulating cross-architecture
+// environments (i.e. arm64 from x86-64 host) which have significantly reduced performance:
+if ( TEST_TIMEOUT_SECONDS )
+    timeout = Number.parseInt(TEST_TIMEOUT_SECONDS, 10) * 1e3;
+
+jest.setTimeout(timeout);
+
+test('salt_length', () => {
+    expect.assertions(EXPECTED);
+
+    return Promise.all(Array.from({length: EXPECTED},
+        () => bcrypt.genSalt(10)
+            .then(salt => expect(salt).toHaveLength(29))));
+})
+
+test('test_hash_length', () => {
+    expect.assertions(EXPECTED);
+    const SALT = '$2a$04$TnjywYklQbbZjdjBgBoA4e';
+    return Promise.all(Array.from({length: EXPECTED},
+        () => bcrypt.hash('test', SALT)
+            .then(hash => expect(hash).toHaveLength(60))));
+})
+
+test('test_compare', () => {
+    expect.assertions(EXPECTED);
+    const HASH = '$2a$04$TnjywYklQbbZjdjBgBoA4e9G7RJt9blgMgsCvUvus4Iv4TENB5nHy';
+    return Promise.all(Array.from({length: EXPECTED},
+        () => bcrypt.compare('test', HASH)
+            .then(match => expect(match).toEqual(true))));
+})
+
+test('test_hash_and_compare', () => {
+    expect.assertions(EXPECTED * 3);
+    const salt = bcrypt.genSaltSync(4)
+
+    return Promise.all(Array.from({length: EXPECTED},
+        () => {
+            const password = 'secret' + Math.random();
+            return bcrypt.hash(password, salt)
+                .then(hash => {
+                    expect(hash).toHaveLength(60);
+                    const goodCompare = bcrypt.compare(password, hash).then(res => expect(res).toEqual(true));
+                    const badCompare = bcrypt.compare('bad' + password, hash).then(res => expect(res).toEqual(false));
+
+                    return Promise.all([goodCompare, badCompare]);
+                });
+        }));
+}, timeout * 3);
+
diff --git a/server/node_modules/bcrypt/test/sync.test.js b/server/node_modules/bcrypt/test/sync.test.js
new file mode 100644
index 0000000..2e6809a
--- /dev/null
+++ b/server/node_modules/bcrypt/test/sync.test.js
@@ -0,0 +1,125 @@
+const bcrypt = require('../bcrypt')
+
+test('salt_length', () => {
+    const salt = bcrypt.genSaltSync(13);
+    expect(salt).toHaveLength(29);
+    const [_, version, rounds] = salt.split('$');
+    expect(version).toStrictEqual('2b')
+    expect(rounds).toStrictEqual('13')
+})
+
+test('salt_no_params', () => {
+    const salt = bcrypt.genSaltSync();
+    const [_, version, rounds] = salt.split('$');
+    expect(version).toStrictEqual('2b')
+    expect(rounds).toStrictEqual('10')
+})
+
+test('salt_rounds_is_string_number', () => {
+    expect(() => bcrypt.genSaltSync('10')).toThrowError('rounds must be a number');
+})
+
+test('salt_rounds_is_NaN', () => {
+    expect(() => bcrypt.genSaltSync('b')).toThrowError("rounds must be a number");
+})
+
+test('salt_minor_a', () => {
+    const salt = bcrypt.genSaltSync(10, 'a');
+    const [_, version, rounds] = salt.split('$');
+    expect(version).toStrictEqual('2a')
+    expect(rounds).toStrictEqual('10')
+})
+
+test('salt_minor_b', () => {
+    const salt = bcrypt.genSaltSync(10, 'b');
+    const [_, version, rounds] = salt.split('$');
+    expect(version).toStrictEqual('2b')
+    expect(rounds).toStrictEqual('10')
+})
+
+test('hash', () => {
+    expect(() => bcrypt.hashSync('password', bcrypt.genSaltSync(10))).not.toThrow()
+})
+
+test('hash_rounds', () => {
+    const hash = bcrypt.hashSync('password', 8);
+    expect(bcrypt.getRounds(hash)).toStrictEqual(8)
+})
+
+test('hash_empty_string', () => {
+    expect(() => bcrypt.hashSync('', bcrypt.genSaltSync(10))).not.toThrow();
+    expect(() => bcrypt.hashSync('password', '')).toThrowError('Invalid salt. Salt must be in the form of: $Vers$log2(NumRounds)$saltvalue');
+    expect(() => bcrypt.hashSync('', '')).toThrowError('Invalid salt. Salt must be in the form of: $Vers$log2(NumRounds)$saltvalue');
+})
+
+test('hash_pw_no_params', () => {
+    expect(() => bcrypt.hashSync()).toThrow('data and salt arguments required');
+})
+
+test('hash_pw_one_param', () => {
+    expect(() => bcrypt.hashSync('password')).toThrow('data and salt arguments required');
+})
+
+test('hash_pw_not_hash_str', () => {
+    expect(() => bcrypt.hashSync('password', {})).toThrow("data must be a string or Buffer and salt must either be a salt string or a number of rounds")
+})
+
+test('hash_salt_validity', () => {
+    expect(2);
+    expect(bcrypt.hashSync('password', '$2a$10$somesaltyvaluertsetrse')).toBeDefined()
+    expect(() => bcrypt.hashSync('password', 'some$value')).toThrow('Invalid salt. Salt must be in the form of: $Vers$log2(NumRounds)$saltvalue')
+})
+
+test('verify_salt', () => {
+    const salt = bcrypt.genSaltSync(10);
+    const split_salt = salt.split('$');
+    expect(split_salt[1]).toStrictEqual('2b')
+    expect(split_salt[2]).toStrictEqual('10')
+})
+
+test('verify_salt_min_rounds', () => {
+    const salt = bcrypt.genSaltSync(1);
+    const split_salt = salt.split('$');
+    expect(split_salt[1]).toStrictEqual('2b')
+    expect(split_salt[2]).toStrictEqual('04')
+})
+
+test('verify_salt_max_rounds', () => {
+    const salt = bcrypt.genSaltSync(100);
+    const split_salt = salt.split('$');
+    expect(split_salt[1]).toStrictEqual('2b')
+    expect(split_salt[2]).toStrictEqual('31')
+})
+
+test('hash_compare', () => {
+    const salt = bcrypt.genSaltSync(10);
+    expect(29).toStrictEqual(salt.length)
+    const hash = bcrypt.hashSync("test", salt);
+    expect(bcrypt.compareSync("test", hash)).toBeDefined()
+    expect(!(bcrypt.compareSync("blah", hash))).toBeDefined()
+})
+
+test('hash_compare_empty_strings', () => {
+    expect(!(bcrypt.compareSync("", "password"))).toBeDefined()
+    expect(!(bcrypt.compareSync("", ""))).toBeDefined()
+    expect(!(bcrypt.compareSync("password", ""))).toBeDefined()
+})
+
+test('hash_compare_invalid_strings', () => {
+    const fullString = 'envy1362987212538';
+    const hash = '$2a$10$XOPbrlUPQdwdJUpSrIF6X.LbE14qsMmKGhM1A8W9iqaG3vv1BD7WC';
+    const wut = ':';
+    expect(bcrypt.compareSync(fullString, hash)).toBe(true);
+    expect(bcrypt.compareSync(fullString, wut)).toBe(false);
+})
+
+test('getRounds', () => {
+    const hash = bcrypt.hashSync("test", bcrypt.genSaltSync(9));
+    expect(9).toStrictEqual(bcrypt.getRounds(hash))
+})
+
+test('getRounds', () => {
+    const hash = bcrypt.hashSync("test", bcrypt.genSaltSync(9));
+    expect(9).toStrictEqual(bcrypt.getRounds(hash))
+    expect(() => bcrypt.getRounds('')).toThrow("invalid hash provided");
+});
diff --git a/server/node_modules/better-sqlite3/LICENSE b/server/node_modules/better-sqlite3/LICENSE
new file mode 100644
index 0000000..228f29b
--- /dev/null
+++ b/server/node_modules/better-sqlite3/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2017 Joshua Wise
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/better-sqlite3/README.md b/server/node_modules/better-sqlite3/README.md
new file mode 100644
index 0000000..2c75318
--- /dev/null
+++ b/server/node_modules/better-sqlite3/README.md
@@ -0,0 +1,99 @@
+# better-sqlite3 [![Build Status](https://github.com/JoshuaWise/better-sqlite3/actions/workflows/build.yml/badge.svg)](https://github.com/JoshuaWise/better-sqlite3/actions/workflows/build.yml?query=branch%3Amaster)
+
+The fastest and simplest library for SQLite in Node.js.
+
+- Full transaction support
+- High performance, efficiency, and safety
+- Easy-to-use synchronous API *(better concurrency than an asynchronous API... yes, you read that correctly)*
+- Support for user-defined functions, aggregates, virtual tables, and extensions
+- 64-bit integers *(invisible until you need them)*
+- Worker thread support *(for large/slow queries)*
+
+## Help this project stay strong! 💪
+
+`better-sqlite3` is used by thousands of developers and engineers on a daily basis. Long nights and weekends were spent keeping this project strong and dependable, with no ask for compensation or funding, until now. If your company uses `better-sqlite3`, ask your manager to consider supporting the project:
+
+- [Become a GitHub sponsor](https://github.com/sponsors/JoshuaWise)
+- [Become a backer on Patreon](https://www.patreon.com/joshuawise)
+- [Make a one-time donation on PayPal](https://www.paypal.me/joshuathomaswise)
+
+## How other libraries compare
+
+|   |select 1 row  `get()` |select 100 rows   `all()`  |select 100 rows `iterate()` 1-by-1|insert 1 row `run()`|insert 100 rows in a transaction|
+|---|---|---|---|---|---|
+|better-sqlite3|1x|1x|1x|1x|1x|
+|[sqlite](https://www.npmjs.com/package/sqlite) and [sqlite3](https://www.npmjs.com/package/sqlite3)|11.7x slower|2.9x slower|24.4x slower|2.8x slower|15.6x slower|
+
+> You can verify these results by [running the benchmark yourself](./docs/benchmark.md).
+
+## Installation
+
+```bash
+npm install better-sqlite3
+```
+
+> Requires Node.js v14.21.1 or later. Prebuilt binaries are available for [LTS versions](https://nodejs.org/en/about/releases/). If you have trouble installing, check the [troubleshooting guide](./docs/troubleshooting.md).
+
+## Usage
+
+```js
+const db = require('better-sqlite3')('foobar.db', options);
+
+const row = db.prepare('SELECT * FROM users WHERE id = ?').get(userId);
+console.log(row.firstName, row.lastName, row.email);
+```
+
+Though not required, [it is generally important to set the WAL pragma for performance reasons](https://github.com/WiseLibs/better-sqlite3/blob/master/docs/performance.md).
+
+```js
+db.pragma('journal_mode = WAL');
+```
+
+##### In ES6 module notation:
+
+```js
+import Database from 'better-sqlite3';
+const db = new Database('foobar.db', options);
+db.pragma('journal_mode = WAL');
+```
+
+## Why should I use this instead of [node-sqlite3](https://github.com/mapbox/node-sqlite3)?
+
+- `node-sqlite3` uses asynchronous APIs for tasks that are either CPU-bound or serialized. That's not only bad design, but it wastes tons of resources. It also causes [mutex thrashing](https://en.wikipedia.org/wiki/Resource_contention) which has devastating effects on performance.
+- `node-sqlite3` exposes low-level (C language) memory management functions. `better-sqlite3` does it the JavaScript way, allowing the garbage collector to worry about memory management.
+- `better-sqlite3` is simpler to use, and it provides nice utilities for some operations that are very difficult or impossible in `node-sqlite3`.
+- `better-sqlite3` is much faster than `node-sqlite3` in most cases, and just as fast in all other cases.
+
+#### When is this library not appropriate?
+
+In most cases, if you're attempting something that cannot be reasonably accomplished with `better-sqlite3`, it probably cannot be reasonably accomplished with SQLite in general. For example, if you're executing queries that take one second to complete, and you expect to have many concurrent users executing those queries, no amount of asynchronicity will save you from SQLite's serialized nature. Fortunately, SQLite is very *very* fast. With proper indexing, we've been able to achieve upward of 2000 queries per second with 5-way-joins in a 60 GB database, where each query was handling 5–50 kilobytes of real data.
+
+If you have a performance problem, the most likely causes are inefficient queries, improper indexing, or a lack of [WAL mode](./docs/performance.md)—not `better-sqlite3` itself. However, there are some cases where `better-sqlite3` could be inappropriate:
+
+- If you expect a high volume of concurrent reads each returning many megabytes of data (i.e., videos)
+- If you expect a high volume of concurrent writes (i.e., a social media site)
+- If your database's size is near the terabyte range
+
+For these situations, you should probably use a full-fledged RDBMS such as [PostgreSQL](https://www.postgresql.org/).
+
+## Upgrading
+
+Upgrading your `better-sqlite3` dependency can potentially introduce breaking changes, either in the `better-sqlite3` API (if you upgrade to a new [major version](https://semver.org/)), or between your existing database(s) and the underlying version of SQLite. Before upgrading, review:
+
+* [`better-sqlite3` release notes](https://github.com/WiseLibs/better-sqlite3/releases)
+* [SQLite release history](https://www.sqlite.org/changes.html)
+
+# Documentation
+
+- [API documentation](./docs/api.md)
+- [Performance](./docs/performance.md) (also see [benchmark results](./docs/benchmark.md))
+- [64-bit integer support](./docs/integer.md)
+- [Worker thread support](./docs/threads.md)
+- [Unsafe mode (advanced)](./docs/unsafe.md)
+- [SQLite compilation (advanced)](./docs/compilation.md)
+- [Contribution rules](./docs/contribution.md)
+- [Code of conduct](./docs/conduct.md)
+
+# License
+
+[MIT](./LICENSE)
diff --git a/server/node_modules/better-sqlite3/binding.gyp b/server/node_modules/better-sqlite3/binding.gyp
new file mode 100644
index 0000000..81a1238
--- /dev/null
+++ b/server/node_modules/better-sqlite3/binding.gyp
@@ -0,0 +1,38 @@
+# ===
+# This is the main GYP file, which builds better-sqlite3 with SQLite itself.
+# ===
+
+{
+  'includes': ['deps/common.gypi'],
+  'targets': [
+    {
+      'target_name': 'better_sqlite3',
+      'dependencies': ['deps/sqlite3.gyp:sqlite3'],
+      'sources': ['src/better_sqlite3.cpp'],
+      'cflags_cc': ['-std=c++20'],
+      'xcode_settings': {
+        'OTHER_CPLUSPLUSFLAGS': ['-std=c++20', '-stdlib=libc++'],
+      },
+      'msvs_settings': {
+        'VCCLCompilerTool': {
+          'AdditionalOptions': [
+            '/std:c++20',
+          ],
+        },
+      },
+      'conditions': [
+        ['OS=="linux"', {
+          'ldflags': [
+            '-Wl,-Bsymbolic',
+            '-Wl,--exclude-libs,ALL',
+          ],
+        }],
+      ],
+    },
+    {
+      'target_name': 'test_extension',
+      'dependencies': ['deps/sqlite3.gyp:sqlite3'],
+      'conditions': [['sqlite3 == ""', { 'sources': ['deps/test_extension.c'] }]],
+    },
+  ],
+}
diff --git a/server/node_modules/better-sqlite3/build/Makefile b/server/node_modules/better-sqlite3/build/Makefile
new file mode 100644
index 0000000..3e27794
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Makefile
@@ -0,0 +1,369 @@
+# We borrow heavily from the kernel build setup, though we are simpler since
+# we don't have Kconfig tweaking settings on us.
+
+# The implicit make rules have it looking for RCS files, among other things.
+# We instead explicitly write all the rules we care about.
+# It's even quicker (saves ~200ms) to pass -r on the command line.
+MAKEFLAGS=-r
+
+# The source directory tree.
+srcdir := ..
+abs_srcdir := $(abspath $(srcdir))
+
+# The name of the builddir.
+builddir_name ?= .
+
+# The V=1 flag on command line makes us verbosely print command lines.
+ifdef V
+  quiet=
+else
+  quiet=quiet_
+endif
+
+# Specify BUILDTYPE=Release on the command line for a release build.
+BUILDTYPE ?= Release
+
+# Directory all our build output goes into.
+# Note that this must be two directories beneath src/ for unit tests to pass,
+# as they reach into the src/ directory for data with relative paths.
+builddir ?= $(builddir_name)/$(BUILDTYPE)
+abs_builddir := $(abspath $(builddir))
+depsdir := $(builddir)/.deps
+
+# Object output directory.
+obj := $(builddir)/obj
+abs_obj := $(abspath $(obj))
+
+# We build up a list of every single one of the targets so we can slurp in the
+# generated dependency rule Makefiles in one pass.
+all_deps :=
+
+
+
+CC.target ?= $(CC)
+CFLAGS.target ?= $(CPPFLAGS) $(CFLAGS)
+CXX.target ?= $(CXX)
+CXXFLAGS.target ?= $(CPPFLAGS) $(CXXFLAGS)
+LINK.target ?= $(LINK)
+LDFLAGS.target ?= $(LDFLAGS)
+AR.target ?= $(AR)
+PLI.target ?= pli
+
+# C++ apps need to be linked with g++.
+LINK ?= $(CXX.target)
+
+# TODO(evan): move all cross-compilation logic to gyp-time so we don't need
+# to replicate this environment fallback in make as well.
+CC.host ?= gcc
+CFLAGS.host ?= $(CPPFLAGS_host) $(CFLAGS_host)
+CXX.host ?= g++
+CXXFLAGS.host ?= $(CPPFLAGS_host) $(CXXFLAGS_host)
+LINK.host ?= $(CXX.host)
+LDFLAGS.host ?= $(LDFLAGS_host)
+AR.host ?= ar
+PLI.host ?= pli
+
+# Define a dir function that can handle spaces.
+# http://www.gnu.org/software/make/manual/make.html#Syntax-of-Functions
+# "leading spaces cannot appear in the text of the first argument as written.
+# These characters can be put into the argument value by variable substitution."
+empty :=
+space := $(empty) $(empty)
+
+# http://stackoverflow.com/questions/1189781/using-make-dir-or-notdir-on-a-path-with-spaces
+replace_spaces = $(subst $(space),?,$1)
+unreplace_spaces = $(subst ?,$(space),$1)
+dirx = $(call unreplace_spaces,$(dir $(call replace_spaces,$1)))
+
+# Flags to make gcc output dependency info.  Note that you need to be
+# careful here to use the flags that ccache and distcc can understand.
+# We write to a dep file on the side first and then rename at the end
+# so we can't end up with a broken dep file.
+depfile = $(depsdir)/$(call replace_spaces,$@).d
+DEPFLAGS = -MMD -MF $(depfile).raw
+
+# We have to fixup the deps output in a few ways.
+# (1) the file output should mention the proper .o file.
+# ccache or distcc lose the path to the target, so we convert a rule of
+# the form:
+#   foobar.o: DEP1 DEP2
+# into
+#   path/to/foobar.o: DEP1 DEP2
+# (2) we want missing files not to cause us to fail to build.
+# We want to rewrite
+#   foobar.o: DEP1 DEP2 \
+#               DEP3
+# to
+#   DEP1:
+#   DEP2:
+#   DEP3:
+# so if the files are missing, they're just considered phony rules.
+# We have to do some pretty insane escaping to get those backslashes
+# and dollar signs past make, the shell, and sed at the same time.
+# Doesn't work with spaces, but that's fine: .d files have spaces in
+# their names replaced with other characters.
+define fixup_dep
+# The depfile may not exist if the input file didn't have any #includes.
+touch $(depfile).raw
+# Fixup path as in (1).
+sed -e "s|^$(notdir $@)|$@|" $(depfile).raw >> $(depfile)
+# Add extra rules as in (2).
+# We remove slashes and replace spaces with new lines;
+# remove blank lines;
+# delete the first line and append a colon to the remaining lines.
+sed -e 's|\\||' -e 'y| |\n|' $(depfile).raw |\
+  grep -v '^$$'                             |\
+  sed -e 1d -e 's|$$|:|'                     \
+    >> $(depfile)
+rm $(depfile).raw
+endef
+
+# Command definitions:
+# - cmd_foo is the actual command to run;
+# - quiet_cmd_foo is the brief-output summary of the command.
+
+quiet_cmd_cc = CC($(TOOLSET)) $@
+cmd_cc = $(CC.$(TOOLSET)) -o $@ $< $(GYP_CFLAGS) $(DEPFLAGS) $(CFLAGS.$(TOOLSET)) -c
+
+quiet_cmd_cxx = CXX($(TOOLSET)) $@
+cmd_cxx = $(CXX.$(TOOLSET)) -o $@ $< $(GYP_CXXFLAGS) $(DEPFLAGS) $(CXXFLAGS.$(TOOLSET)) -c
+
+quiet_cmd_touch = TOUCH $@
+cmd_touch = touch $@
+
+quiet_cmd_copy = COPY $@
+# send stderr to /dev/null to ignore messages when linking directories.
+cmd_copy = ln -f "$<" "$@" 2>/dev/null || (rm -rf "$@" && cp -af "$<" "$@")
+
+quiet_cmd_symlink = SYMLINK $@
+cmd_symlink = ln -sf "$<" "$@"
+
+quiet_cmd_alink = AR($(TOOLSET)) $@
+cmd_alink = rm -f $@ && $(AR.$(TOOLSET)) crs $@ $(filter %.o,$^)
+
+quiet_cmd_alink_thin = AR($(TOOLSET)) $@
+cmd_alink_thin = rm -f $@ && $(AR.$(TOOLSET)) crsT $@ $(filter %.o,$^)
+
+# Due to circular dependencies between libraries :(, we wrap the
+# special "figure out circular dependencies" flags around the entire
+# input list during linking.
+quiet_cmd_link = LINK($(TOOLSET)) $@
+cmd_link = $(LINK.$(TOOLSET)) -o $@ $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -Wl,--start-group $(LD_INPUTS) $(LIBS) -Wl,--end-group
+
+# Note: this does not handle spaces in paths
+define xargs
+  $(1) $(word 1,$(2))
+$(if $(word 2,$(2)),$(call xargs,$(1),$(wordlist 2,$(words $(2)),$(2))))
+endef
+
+define write-to-file
+  @: >$(1)
+$(call xargs,@printf "%s\n" >>$(1),$(2))
+endef
+
+OBJ_FILE_LIST := ar-file-list
+
+define create_archive
+        rm -f $(1) $(1).$(OBJ_FILE_LIST); mkdir -p `dirname $(1)`
+        $(call write-to-file,$(1).$(OBJ_FILE_LIST),$(filter %.o,$(2)))
+        $(AR.$(TOOLSET)) crs $(1) @$(1).$(OBJ_FILE_LIST)
+endef
+
+define create_thin_archive
+        rm -f $(1) $(OBJ_FILE_LIST); mkdir -p `dirname $(1)`
+        $(call write-to-file,$(1).$(OBJ_FILE_LIST),$(filter %.o,$(2)))
+        $(AR.$(TOOLSET)) crsT $(1) @$(1).$(OBJ_FILE_LIST)
+endef
+
+# We support two kinds of shared objects (.so):
+# 1) shared_library, which is just bundling together many dependent libraries
+# into a link line.
+# 2) loadable_module, which is generating a module intended for dlopen().
+#
+# They differ only slightly:
+# In the former case, we want to package all dependent code into the .so.
+# In the latter case, we want to package just the API exposed by the
+# outermost module.
+# This means shared_library uses --whole-archive, while loadable_module doesn't.
+# (Note that --whole-archive is incompatible with the --start-group used in
+# normal linking.)
+
+# Other shared-object link notes:
+# - Set SONAME to the library filename so our binaries don't reference
+# the local, absolute paths used on the link command-line.
+quiet_cmd_solink = SOLINK($(TOOLSET)) $@
+cmd_solink = $(LINK.$(TOOLSET)) -o $@ -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -Wl,-soname=$(@F) -Wl,--whole-archive $(LD_INPUTS) -Wl,--no-whole-archive $(LIBS)
+
+quiet_cmd_solink_module = SOLINK_MODULE($(TOOLSET)) $@
+cmd_solink_module = $(LINK.$(TOOLSET)) -o $@ -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -Wl,-soname=$(@F) -Wl,--start-group $(filter-out FORCE_DO_CMD, $^) -Wl,--end-group $(LIBS)
+
+
+# Define an escape_quotes function to escape single quotes.
+# This allows us to handle quotes properly as long as we always use
+# use single quotes and escape_quotes.
+escape_quotes = $(subst ','\'',$(1))
+# This comment is here just to include a ' to unconfuse syntax highlighting.
+# Define an escape_vars function to escape '$' variable syntax.
+# This allows us to read/write command lines with shell variables (e.g.
+# $LD_LIBRARY_PATH), without triggering make substitution.
+escape_vars = $(subst $$,$$$$,$(1))
+# Helper that expands to a shell command to echo a string exactly as it is in
+# make. This uses printf instead of echo because printf's behaviour with respect
+# to escape sequences is more portable than echo's across different shells
+# (e.g., dash, bash).
+exact_echo = printf '%s\n' '$(call escape_quotes,$(1))'
+
+# Helper to compare the command we're about to run against the command
+# we logged the last time we ran the command.  Produces an empty
+# string (false) when the commands match.
+# Tricky point: Make has no string-equality test function.
+# The kernel uses the following, but it seems like it would have false
+# positives, where one string reordered its arguments.
+#   arg_check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
+#                       $(filter-out $(cmd_$@), $(cmd_$(1))))
+# We instead substitute each for the empty string into the other, and
+# say they're equal if both substitutions produce the empty string.
+# .d files contain ? instead of spaces, take that into account.
+command_changed = $(or $(subst $(cmd_$(1)),,$(cmd_$(call replace_spaces,$@))),\
+                       $(subst $(cmd_$(call replace_spaces,$@)),,$(cmd_$(1))))
+
+# Helper that is non-empty when a prerequisite changes.
+# Normally make does this implicitly, but we force rules to always run
+# so we can check their command lines.
+#   $? -- new prerequisites
+#   $| -- order-only dependencies
+prereq_changed = $(filter-out FORCE_DO_CMD,$(filter-out $|,$?))
+
+# Helper that executes all postbuilds until one fails.
+define do_postbuilds
+  @E=0;\
+  for p in $(POSTBUILDS); do\
+    eval $$p;\
+    E=$$?;\
+    if [ $$E -ne 0 ]; then\
+      break;\
+    fi;\
+  done;\
+  if [ $$E -ne 0 ]; then\
+    rm -rf "$@";\
+    exit $$E;\
+  fi
+endef
+
+# do_cmd: run a command via the above cmd_foo names, if necessary.
+# Should always run for a given target to handle command-line changes.
+# Second argument, if non-zero, makes it do asm/C/C++ dependency munging.
+# Third argument, if non-zero, makes it do POSTBUILDS processing.
+# Note: We intentionally do NOT call dirx for depfile, since it contains ? for
+# spaces already and dirx strips the ? characters.
+define do_cmd
+$(if $(or $(command_changed),$(prereq_changed)),
+  @$(call exact_echo,  $($(quiet)cmd_$(1)))
+  @mkdir -p "$(call dirx,$@)" "$(dir $(depfile))"
+  $(if $(findstring flock,$(word 1,$(cmd_$1))),
+    @$(cmd_$(1))
+    @echo "  $(quiet_cmd_$(1)): Finished",
+    @$(cmd_$(1))
+  )
+  @$(call exact_echo,$(call escape_vars,cmd_$(call replace_spaces,$@) := $(cmd_$(1)))) > $(depfile)
+  @$(if $(2),$(fixup_dep))
+  $(if $(and $(3), $(POSTBUILDS)),
+    $(call do_postbuilds)
+  )
+)
+endef
+
+# Declare the "all" target first so it is the default,
+# even though we don't have the deps yet.
+.PHONY: all
+all:
+
+# make looks for ways to re-generate included makefiles, but in our case, we
+# don't have a direct way. Explicitly telling make that it has nothing to do
+# for them makes it go faster.
+%.d: ;
+
+# Use FORCE_DO_CMD to force a target to run.  Should be coupled with
+# do_cmd.
+.PHONY: FORCE_DO_CMD
+FORCE_DO_CMD:
+
+TOOLSET := target
+# Suffix rules, putting all outputs into $(obj).
+$(obj).$(TOOLSET)/%.o: $(srcdir)/%.c FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+$(obj).$(TOOLSET)/%.o: $(srcdir)/%.cc FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+$(obj).$(TOOLSET)/%.o: $(srcdir)/%.cpp FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+$(obj).$(TOOLSET)/%.o: $(srcdir)/%.cxx FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+$(obj).$(TOOLSET)/%.o: $(srcdir)/%.s FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+$(obj).$(TOOLSET)/%.o: $(srcdir)/%.S FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+
+# Try building from generated source, too.
+$(obj).$(TOOLSET)/%.o: $(obj).$(TOOLSET)/%.c FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+$(obj).$(TOOLSET)/%.o: $(obj).$(TOOLSET)/%.cc FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+$(obj).$(TOOLSET)/%.o: $(obj).$(TOOLSET)/%.cpp FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+$(obj).$(TOOLSET)/%.o: $(obj).$(TOOLSET)/%.cxx FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+$(obj).$(TOOLSET)/%.o: $(obj).$(TOOLSET)/%.s FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+$(obj).$(TOOLSET)/%.o: $(obj).$(TOOLSET)/%.S FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+
+$(obj).$(TOOLSET)/%.o: $(obj)/%.c FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+$(obj).$(TOOLSET)/%.o: $(obj)/%.cc FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+$(obj).$(TOOLSET)/%.o: $(obj)/%.cpp FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+$(obj).$(TOOLSET)/%.o: $(obj)/%.cxx FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+$(obj).$(TOOLSET)/%.o: $(obj)/%.s FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+$(obj).$(TOOLSET)/%.o: $(obj)/%.S FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+
+
+ifeq ($(strip $(foreach prefix,$(NO_LOAD),\
+    $(findstring $(join ^,$(prefix)),\
+                 $(join ^,better_sqlite3.target.mk)))),)
+  include better_sqlite3.target.mk
+endif
+ifeq ($(strip $(foreach prefix,$(NO_LOAD),\
+    $(findstring $(join ^,$(prefix)),\
+                 $(join ^,deps/locate_sqlite3.target.mk)))),)
+  include deps/locate_sqlite3.target.mk
+endif
+ifeq ($(strip $(foreach prefix,$(NO_LOAD),\
+    $(findstring $(join ^,$(prefix)),\
+                 $(join ^,deps/sqlite3.target.mk)))),)
+  include deps/sqlite3.target.mk
+endif
+ifeq ($(strip $(foreach prefix,$(NO_LOAD),\
+    $(findstring $(join ^,$(prefix)),\
+                 $(join ^,test_extension.target.mk)))),)
+  include test_extension.target.mk
+endif
+
+quiet_cmd_regen_makefile = ACTION Regenerating $@
+cmd_regen_makefile = cd $(srcdir); /home/linuxbrew/.linuxbrew/lib/node_modules/npm/node_modules/node-gyp/gyp/gyp_main.py -fmake --ignore-environment "-Dlibrary=shared_library" "-Dvisibility=default" "-Dnode_root_dir=/home/fahed/.cache/node-gyp/25.5.0" "-Dnode_gyp_dir=/home/linuxbrew/.linuxbrew/lib/node_modules/npm/node_modules/node-gyp" "-Dnode_lib_file=/home/fahed/.cache/node-gyp/25.5.0/<(target_arch)/node.lib" "-Dmodule_root_dir=/home/fahed/clawd/marketing-app/server/node_modules/better-sqlite3" "-Dnode_engine=v8" "--depth=." "-Goutput_dir=." "--generator-output=build" -I/home/fahed/clawd/marketing-app/server/node_modules/better-sqlite3/build/config.gypi -I/home/linuxbrew/.linuxbrew/lib/node_modules/npm/node_modules/node-gyp/addon.gypi -I/home/fahed/.cache/node-gyp/25.5.0/include/node/common.gypi "--toplevel-dir=." binding.gyp
+Makefile: $(srcdir)/../../../../../../linuxbrew/.linuxbrew/lib/node_modules/npm/node_modules/node-gyp/addon.gypi $(srcdir)/../../../../../.cache/node-gyp/25.5.0/include/node/common.gypi $(srcdir)/binding.gyp $(srcdir)/build/config.gypi $(srcdir)/deps/common.gypi $(srcdir)/deps/defines.gypi $(srcdir)/deps/sqlite3.gyp
+	$(call do_cmd,regen_makefile)
+
+# "all" is a concatenation of the "all" targets from all the included
+# sub-makefiles. This is just here to clarify.
+all:
+
+# Add in dependency-tracking rules.  $(all_deps) is the list of every single
+# target in our tree. Only consider the ones with .d (dependency) info:
+d_files := $(wildcard $(foreach f,$(all_deps),$(depsdir)/$(f).d))
+ifneq ($(d_files),)
+  include $(d_files)
+endif
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/Release/better_sqlite3.node.d b/server/node_modules/better-sqlite3/build/Release/.deps/Release/better_sqlite3.node.d
new file mode 100644
index 0000000..7069040
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/Release/better_sqlite3.node.d
@@ -0,0 +1 @@
+cmd_Release/better_sqlite3.node := ln -f "Release/obj.target/better_sqlite3.node" "Release/better_sqlite3.node" 2>/dev/null || (rm -rf "Release/better_sqlite3.node" && cp -af "Release/obj.target/better_sqlite3.node" "Release/better_sqlite3.node")
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/better_sqlite3.node.d b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/better_sqlite3.node.d
new file mode 100644
index 0000000..5f55dcf
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/better_sqlite3.node.d
@@ -0,0 +1 @@
+cmd_Release/obj.target/better_sqlite3.node := g++ -o Release/obj.target/better_sqlite3.node -shared -pthread -rdynamic -fPIC -Wl,-Bsymbolic -Wl,--exclude-libs,ALL -m64  -Wl,-soname=better_sqlite3.node -Wl,--start-group Release/obj.target/better_sqlite3/src/better_sqlite3.o Release/obj.target/deps/sqlite3.a -Wl,--end-group 
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/better_sqlite3/src/better_sqlite3.o.d b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/better_sqlite3/src/better_sqlite3.o.d
new file mode 100644
index 0000000..4fcff50
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/better_sqlite3/src/better_sqlite3.o.d
@@ -0,0 +1,153 @@
+cmd_Release/obj.target/better_sqlite3/src/better_sqlite3.o := g++ -o Release/obj.target/better_sqlite3/src/better_sqlite3.o ../src/better_sqlite3.cpp '-DNODE_GYP_MODULE_NAME=better_sqlite3' '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-D_GLIBCXX_USE_CXX11_ABI=1' '-D_FILE_OFFSET_BITS=64' '-D_LARGEFILE_SOURCE' '-D__STDC_FORMAT_MACROS' '-DBUILDING_NODE_EXTENSION' '-DNDEBUG' -I/home/fahed/.cache/node-gyp/25.5.0/include/node -I/home/fahed/.cache/node-gyp/25.5.0/src -I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/config -I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/openssl/include -I/home/fahed/.cache/node-gyp/25.5.0/deps/uv/include -I/home/fahed/.cache/node-gyp/25.5.0/deps/zlib -I/home/fahed/.cache/node-gyp/25.5.0/deps/v8/include -I./Release/obj/gen/sqlite3  -fPIC -pthread -Wall -Wextra -Wno-unused-parameter -fPIC -m64 -O3 -O3 -fno-omit-frame-pointer -fno-rtti -fno-exceptions -fno-strict-aliasing -std=gnu++20 -std=c++20 -MMD -MF ./Release/.deps/Release/obj.target/better_sqlite3/src/better_sqlite3.o.d.raw   -c
+Release/obj.target/better_sqlite3/src/better_sqlite3.o: \
+ ../src/better_sqlite3.cpp ../src/better_sqlite3.hpp \
+ Release/obj/gen/sqlite3/sqlite3.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/node.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/common.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8config.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-array-buffer.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-local-handle.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-handle-base.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-internal.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8config.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-memory-span.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-object.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/garbage-collected.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/internal/api-constants.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/platform.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/source-location.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-source-location.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-platform.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-source-location.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/trace-trait.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/type-traits.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/name-provider.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-maybe.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/internal/conditional-stack-allocated.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/macros.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/internal/compiler-specific.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-persistent-handle.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-weak-callback-info.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-primitive.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-data.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-value.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-sandbox.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-traced-handle.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-platform.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-container.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-context.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-snapshot.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-isolate.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-callbacks.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-promise.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-debug.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-script.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-message.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-embedder-heap.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-exception.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-function-callback.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-microtask.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-statistics.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-unwinder.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-embedder-state-scope.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-date.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-extension.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-external.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-function.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-template.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-initialization.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-json.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-locker.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-microtask-queue.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-primitive-object.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-proxy.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-regexp.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-typed-array.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-value-serializer.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-version.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/v8-wasm.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/node_version.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/node_api.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/js_native_api.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/js_native_api_types.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/node_api_types.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/node_object_wrap.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/node_buffer.h \
+ /home/fahed/.cache/node-gyp/25.5.0/include/node/node.h
+../src/better_sqlite3.cpp:
+../src/better_sqlite3.hpp:
+Release/obj/gen/sqlite3/sqlite3.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/node.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/common.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8config.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-array-buffer.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-local-handle.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-handle-base.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-internal.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8config.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-memory-span.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-object.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/garbage-collected.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/internal/api-constants.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/platform.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/source-location.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-source-location.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-platform.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-source-location.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/trace-trait.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/type-traits.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/name-provider.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-maybe.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/internal/conditional-stack-allocated.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/macros.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/cppgc/internal/compiler-specific.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-persistent-handle.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-weak-callback-info.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-primitive.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-data.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-value.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-sandbox.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-traced-handle.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-platform.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-container.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-context.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-snapshot.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-isolate.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-callbacks.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-promise.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-debug.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-script.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-message.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-embedder-heap.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-exception.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-function-callback.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-microtask.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-statistics.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-unwinder.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-embedder-state-scope.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-date.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-extension.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-external.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-function.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-template.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-initialization.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-json.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-locker.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-microtask-queue.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-primitive-object.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-proxy.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-regexp.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-typed-array.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-value-serializer.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-version.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/v8-wasm.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/node_version.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/node_api.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/js_native_api.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/js_native_api_types.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/node_api_types.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/node_object_wrap.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/node_buffer.h:
+/home/fahed/.cache/node-gyp/25.5.0/include/node/node.h:
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/deps/locate_sqlite3.stamp.d b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/deps/locate_sqlite3.stamp.d
new file mode 100644
index 0000000..a3d358b
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/deps/locate_sqlite3.stamp.d
@@ -0,0 +1 @@
+cmd_Release/obj.target/deps/locate_sqlite3.stamp := touch Release/obj.target/deps/locate_sqlite3.stamp
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/sqlite3/gen/sqlite3/sqlite3.o.d b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/sqlite3/gen/sqlite3/sqlite3.o.d
new file mode 100644
index 0000000..13ea421
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/sqlite3/gen/sqlite3/sqlite3.o.d
@@ -0,0 +1,4 @@
+cmd_Release/obj.target/sqlite3/gen/sqlite3/sqlite3.o := cc -o Release/obj.target/sqlite3/gen/sqlite3/sqlite3.o Release/obj/gen/sqlite3/sqlite3.c '-DNODE_GYP_MODULE_NAME=sqlite3' '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-D_GLIBCXX_USE_CXX11_ABI=1' '-D_FILE_OFFSET_BITS=64' '-D_LARGEFILE_SOURCE' '-D__STDC_FORMAT_MACROS' '-DHAVE_INT16_T=1' '-DHAVE_INT32_T=1' '-DHAVE_INT8_T=1' '-DHAVE_STDINT_H=1' '-DHAVE_UINT16_T=1' '-DHAVE_UINT32_T=1' '-DHAVE_UINT8_T=1' '-DHAVE_USLEEP=1' '-DSQLITE_DEFAULT_CACHE_SIZE=-16000' '-DSQLITE_DEFAULT_FOREIGN_KEYS=1' '-DSQLITE_DEFAULT_MEMSTATUS=0' '-DSQLITE_DEFAULT_WAL_SYNCHRONOUS=1' '-DSQLITE_DQS=0' '-DSQLITE_ENABLE_COLUMN_METADATA' '-DSQLITE_ENABLE_DBSTAT_VTAB' '-DSQLITE_ENABLE_DESERIALIZE' '-DSQLITE_ENABLE_FTS3' '-DSQLITE_ENABLE_FTS3_PARENTHESIS' '-DSQLITE_ENABLE_FTS4' '-DSQLITE_ENABLE_FTS5' '-DSQLITE_ENABLE_GEOPOLY' '-DSQLITE_ENABLE_JSON1' '-DSQLITE_ENABLE_MATH_FUNCTIONS' '-DSQLITE_ENABLE_RTREE' '-DSQLITE_ENABLE_STAT4' '-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT' '-DSQLITE_LIKE_DOESNT_MATCH_BLOBS' '-DSQLITE_OMIT_DEPRECATED' '-DSQLITE_OMIT_PROGRESS_CALLBACK' '-DSQLITE_OMIT_SHARED_CACHE' '-DSQLITE_OMIT_TCL_VARIABLE' '-DSQLITE_SOUNDEX' '-DSQLITE_THREADSAFE=2' '-DSQLITE_TRACE_SIZE_LIMIT=32' '-DSQLITE_USE_URI=0' '-DNDEBUG' -I/home/fahed/.cache/node-gyp/25.5.0/include/node -I/home/fahed/.cache/node-gyp/25.5.0/src -I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/config -I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/openssl/include -I/home/fahed/.cache/node-gyp/25.5.0/deps/uv/include -I/home/fahed/.cache/node-gyp/25.5.0/deps/zlib -I/home/fahed/.cache/node-gyp/25.5.0/deps/v8/include -I./Release/obj/gen/sqlite3  -fPIC -pthread -Wall -Wextra -Wno-unused-parameter -fPIC -std=c99 -w -m64 -O3 -O3 -fno-omit-frame-pointer  -MMD -MF ./Release/.deps/Release/obj.target/sqlite3/gen/sqlite3/sqlite3.o.d.raw   -c
+Release/obj.target/sqlite3/gen/sqlite3/sqlite3.o: \
+ Release/obj/gen/sqlite3/sqlite3.c
+Release/obj/gen/sqlite3/sqlite3.c:
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/test_extension.node.d b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/test_extension.node.d
new file mode 100644
index 0000000..14631ec
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/test_extension.node.d
@@ -0,0 +1 @@
+cmd_Release/obj.target/test_extension.node := g++ -o Release/obj.target/test_extension.node -shared -pthread -rdynamic -fPIC -m64  -Wl,-soname=test_extension.node -Wl,--start-group Release/obj.target/test_extension/deps/test_extension.o Release/obj.target/deps/sqlite3.a -Wl,--end-group 
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/test_extension/deps/test_extension.o.d b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/test_extension/deps/test_extension.o.d
new file mode 100644
index 0000000..3be5866
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/Release/obj.target/test_extension/deps/test_extension.o.d
@@ -0,0 +1,7 @@
+cmd_Release/obj.target/test_extension/deps/test_extension.o := cc -o Release/obj.target/test_extension/deps/test_extension.o ../deps/test_extension.c '-DNODE_GYP_MODULE_NAME=test_extension' '-DUSING_UV_SHARED=1' '-DUSING_V8_SHARED=1' '-DV8_DEPRECATION_WARNINGS=1' '-D_GLIBCXX_USE_CXX11_ABI=1' '-D_FILE_OFFSET_BITS=64' '-D_LARGEFILE_SOURCE' '-D__STDC_FORMAT_MACROS' '-DBUILDING_NODE_EXTENSION' '-DNDEBUG' -I/home/fahed/.cache/node-gyp/25.5.0/include/node -I/home/fahed/.cache/node-gyp/25.5.0/src -I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/config -I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/openssl/include -I/home/fahed/.cache/node-gyp/25.5.0/deps/uv/include -I/home/fahed/.cache/node-gyp/25.5.0/deps/zlib -I/home/fahed/.cache/node-gyp/25.5.0/deps/v8/include -I./Release/obj/gen/sqlite3  -fPIC -pthread -Wall -Wextra -Wno-unused-parameter -fPIC -m64 -O3 -O3 -fno-omit-frame-pointer  -MMD -MF ./Release/.deps/Release/obj.target/test_extension/deps/test_extension.o.d.raw   -c
+Release/obj.target/test_extension/deps/test_extension.o: \
+ ../deps/test_extension.c Release/obj/gen/sqlite3/sqlite3ext.h \
+ Release/obj/gen/sqlite3/sqlite3.h
+../deps/test_extension.c:
+Release/obj/gen/sqlite3/sqlite3ext.h:
+Release/obj/gen/sqlite3/sqlite3.h:
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/Release/sqlite3.a.d b/server/node_modules/better-sqlite3/build/Release/.deps/Release/sqlite3.a.d
new file mode 100644
index 0000000..5508fb1
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/Release/sqlite3.a.d
@@ -0,0 +1 @@
+cmd_Release/sqlite3.a := ln -f "Release/obj.target/deps/sqlite3.a" "Release/sqlite3.a" 2>/dev/null || (rm -rf "Release/sqlite3.a" && cp -af "Release/obj.target/deps/sqlite3.a" "Release/sqlite3.a")
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/Release/test_extension.node.d b/server/node_modules/better-sqlite3/build/Release/.deps/Release/test_extension.node.d
new file mode 100644
index 0000000..963c074
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/Release/test_extension.node.d
@@ -0,0 +1 @@
+cmd_Release/test_extension.node := ln -f "Release/obj.target/test_extension.node" "Release/test_extension.node" 2>/dev/null || (rm -rf "Release/test_extension.node" && cp -af "Release/obj.target/test_extension.node" "Release/test_extension.node")
diff --git a/server/node_modules/better-sqlite3/build/Release/.deps/ba23eeee118cd63e16015df367567cb043fed872.intermediate.d b/server/node_modules/better-sqlite3/build/Release/.deps/ba23eeee118cd63e16015df367567cb043fed872.intermediate.d
new file mode 100644
index 0000000..0f16ba0
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/.deps/ba23eeee118cd63e16015df367567cb043fed872.intermediate.d
@@ -0,0 +1 @@
+cmd_ba23eeee118cd63e16015df367567cb043fed872.intermediate := LD_LIBRARY_PATH=/home/fahed/clawd/marketing-app/server/node_modules/better-sqlite3/build/Release/lib.host:/home/fahed/clawd/marketing-app/server/node_modules/better-sqlite3/build/Release/lib.target:$$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; cd ../deps; mkdir -p /home/fahed/clawd/marketing-app/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3; node copy.js "/home/fahed/clawd/marketing-app/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3" ""
diff --git a/server/node_modules/better-sqlite3/build/Release/better_sqlite3.node b/server/node_modules/better-sqlite3/build/Release/better_sqlite3.node
new file mode 100755
index 0000000..9700b39
Binary files /dev/null and b/server/node_modules/better-sqlite3/build/Release/better_sqlite3.node differ
diff --git a/server/node_modules/better-sqlite3/build/Release/obj.target/better_sqlite3.node b/server/node_modules/better-sqlite3/build/Release/obj.target/better_sqlite3.node
new file mode 100755
index 0000000..9700b39
Binary files /dev/null and b/server/node_modules/better-sqlite3/build/Release/obj.target/better_sqlite3.node differ
diff --git a/server/node_modules/better-sqlite3/build/Release/obj.target/better_sqlite3/src/better_sqlite3.o b/server/node_modules/better-sqlite3/build/Release/obj.target/better_sqlite3/src/better_sqlite3.o
new file mode 100644
index 0000000..13b5dba
Binary files /dev/null and b/server/node_modules/better-sqlite3/build/Release/obj.target/better_sqlite3/src/better_sqlite3.o differ
diff --git a/server/node_modules/better-sqlite3/build/Release/obj.target/deps/locate_sqlite3.stamp b/server/node_modules/better-sqlite3/build/Release/obj.target/deps/locate_sqlite3.stamp
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/better-sqlite3/build/Release/obj.target/deps/sqlite3.a b/server/node_modules/better-sqlite3/build/Release/obj.target/deps/sqlite3.a
new file mode 100644
index 0000000..89b4dbf
Binary files /dev/null and b/server/node_modules/better-sqlite3/build/Release/obj.target/deps/sqlite3.a differ
diff --git a/server/node_modules/better-sqlite3/build/Release/obj.target/deps/sqlite3.a.ar-file-list b/server/node_modules/better-sqlite3/build/Release/obj.target/deps/sqlite3.a.ar-file-list
new file mode 100644
index 0000000..efc3186
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/obj.target/deps/sqlite3.a.ar-file-list
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+Release/obj.target/sqlite3/gen/sqlite3/sqlite3.o
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diff --git a/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3/sqlite3.c b/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3/sqlite3.c
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--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3/sqlite3.c
@@ -0,0 +1,261480 @@
+/******************************************************************************
+** This file is an amalgamation of many separate C source files from SQLite
+** version 3.49.2.  By combining all the individual C code files into this
+** single large file, the entire code can be compiled as a single translation
+** unit.  This allows many compilers to do optimizations that would not be
+** possible if the files were compiled separately.  Performance improvements
+** of 5% or more are commonly seen when SQLite is compiled as a single
+** translation unit.
+**
+** This file is all you need to compile SQLite.  To use SQLite in other
+** programs, you need this file and the "sqlite3.h" header file that defines
+** the programming interface to the SQLite library.  (If you do not have
+** the "sqlite3.h" header file at hand, you will find a copy embedded within
+** the text of this file.  Search for "Begin file sqlite3.h" to find the start
+** of the embedded sqlite3.h header file.) Additional code files may be needed
+** if you want a wrapper to interface SQLite with your choice of programming
+** language. The code for the "sqlite3" command-line shell is also in a
+** separate file. This file contains only code for the core SQLite library.
+**
+** The content in this amalgamation comes from Fossil check-in
+** 17144570b0d96ae63cd6f3edca39e27ebd74 with changes in files:
+**
+**    
+*/
+#ifndef SQLITE_AMALGAMATION
+#define SQLITE_CORE 1
+#define SQLITE_AMALGAMATION 1
+#ifndef SQLITE_PRIVATE
+# define SQLITE_PRIVATE static
+#endif
+#define SQLITE_UDL_CAPABLE_PARSER 1
+/************** Begin file sqliteInt.h ***************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Internal interface definitions for SQLite.
+**
+*/
+#ifndef SQLITEINT_H
+#define SQLITEINT_H
+
+/* Special Comments:
+**
+** Some comments have special meaning to the tools that measure test
+** coverage:
+**
+**    NO_TEST                     - The branches on this line are not
+**                                  measured by branch coverage.  This is
+**                                  used on lines of code that actually
+**                                  implement parts of coverage testing.
+**
+**    OPTIMIZATION-IF-TRUE        - This branch is allowed to always be false
+**                                  and the correct answer is still obtained,
+**                                  though perhaps more slowly.
+**
+**    OPTIMIZATION-IF-FALSE       - This branch is allowed to always be true
+**                                  and the correct answer is still obtained,
+**                                  though perhaps more slowly.
+**
+**    PREVENTS-HARMLESS-OVERREAD  - This branch prevents a buffer overread
+**                                  that would be harmless and undetectable
+**                                  if it did occur.
+**
+** In all cases, the special comment must be enclosed in the usual
+** slash-asterisk...asterisk-slash comment marks, with no spaces between the
+** asterisks and the comment text.
+*/
+
+/*
+** Make sure the Tcl calling convention macro is defined.  This macro is
+** only used by test code and Tcl integration code.
+*/
+#ifndef SQLITE_TCLAPI
+#  define SQLITE_TCLAPI
+#endif
+
+/*
+** Include the header file used to customize the compiler options for MSVC.
+** This should be done first so that it can successfully prevent spurious
+** compiler warnings due to subsequent content in this file and other files
+** that are included by this file.
+*/
+/************** Include msvc.h in the middle of sqliteInt.h ******************/
+/************** Begin file msvc.h ********************************************/
+/*
+** 2015 January 12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to MSVC.
+*/
+#ifndef SQLITE_MSVC_H
+#define SQLITE_MSVC_H
+
+#if defined(_MSC_VER)
+#pragma warning(disable : 4054)
+#pragma warning(disable : 4055)
+#pragma warning(disable : 4100)
+#pragma warning(disable : 4127)
+#pragma warning(disable : 4130)
+#pragma warning(disable : 4152)
+#pragma warning(disable : 4189)
+#pragma warning(disable : 4206)
+#pragma warning(disable : 4210)
+#pragma warning(disable : 4232)
+#pragma warning(disable : 4244)
+#pragma warning(disable : 4305)
+#pragma warning(disable : 4306)
+#pragma warning(disable : 4702)
+#pragma warning(disable : 4706)
+#endif /* defined(_MSC_VER) */
+
+#if defined(_MSC_VER) && !defined(_WIN64)
+#undef SQLITE_4_BYTE_ALIGNED_MALLOC
+#define SQLITE_4_BYTE_ALIGNED_MALLOC
+#endif /* defined(_MSC_VER) && !defined(_WIN64) */
+
+#if !defined(HAVE_LOG2) && defined(_MSC_VER) && _MSC_VER<1800
+#define HAVE_LOG2 0
+#endif /* !defined(HAVE_LOG2) && defined(_MSC_VER) && _MSC_VER<1800 */
+
+#endif /* SQLITE_MSVC_H */
+
+/************** End of msvc.h ************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/*
+** Special setup for VxWorks
+*/
+/************** Include vxworks.h in the middle of sqliteInt.h ***************/
+/************** Begin file vxworks.h *****************************************/
+/*
+** 2015-03-02
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to Wind River's VxWorks
+*/
+#if defined(__RTP__) || defined(_WRS_KERNEL)
+/* This is VxWorks.  Set up things specially for that OS
+*/
+#include <vxWorks.h>
+#include <pthread.h>  /* amalgamator: dontcache */
+#define OS_VXWORKS 1
+#define SQLITE_OS_OTHER 0
+#define SQLITE_HOMEGROWN_RECURSIVE_MUTEX 1
+#define SQLITE_OMIT_LOAD_EXTENSION 1
+#define SQLITE_ENABLE_LOCKING_STYLE 0
+#define HAVE_UTIME 1
+#else
+/* This is not VxWorks. */
+#define OS_VXWORKS 0
+#define HAVE_FCHOWN 1
+#define HAVE_READLINK 1
+#define HAVE_LSTAT 1
+#endif /* defined(_WRS_KERNEL) */
+
+/************** End of vxworks.h *********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/*
+** These #defines should enable >2GB file support on POSIX if the
+** underlying operating system supports it.  If the OS lacks
+** large file support, or if the OS is windows, these should be no-ops.
+**
+** Ticket #2739:  The _LARGEFILE_SOURCE macro must appear before any
+** system #includes.  Hence, this block of code must be the very first
+** code in all source files.
+**
+** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
+** on the compiler command line.  This is necessary if you are compiling
+** on a recent machine (ex: Red Hat 7.2) but you want your code to work
+** on an older machine (ex: Red Hat 6.0).  If you compile on Red Hat 7.2
+** without this option, LFS is enable.  But LFS does not exist in the kernel
+** in Red Hat 6.0, so the code won't work.  Hence, for maximum binary
+** portability you should omit LFS.
+**
+** The previous paragraph was written in 2005.  (This paragraph is written
+** on 2008-11-28.) These days, all Linux kernels support large files, so
+** you should probably leave LFS enabled.  But some embedded platforms might
+** lack LFS in which case the SQLITE_DISABLE_LFS macro might still be useful.
+**
+** Similar is true for Mac OS X.  LFS is only supported on Mac OS X 9 and later.
+*/
+#ifndef SQLITE_DISABLE_LFS
+# define _LARGE_FILE       1
+# ifndef _FILE_OFFSET_BITS
+#   define _FILE_OFFSET_BITS 64
+# endif
+# define _LARGEFILE_SOURCE 1
+#endif
+
+/* The GCC_VERSION and MSVC_VERSION macros are used to
+** conditionally include optimizations for each of these compilers.  A
+** value of 0 means that compiler is not being used.  The
+** SQLITE_DISABLE_INTRINSIC macro means do not use any compiler-specific
+** optimizations, and hence set all compiler macros to 0
+**
+** There was once also a CLANG_VERSION macro.  However, we learn that the
+** version numbers in clang are for "marketing" only and are inconsistent
+** and unreliable.  Fortunately, all versions of clang also recognize the
+** gcc version numbers and have reasonable settings for gcc version numbers,
+** so the GCC_VERSION macro will be set to a correct non-zero value even
+** when compiling with clang.
+*/
+#if defined(__GNUC__) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define GCC_VERSION (__GNUC__*1000000+__GNUC_MINOR__*1000+__GNUC_PATCHLEVEL__)
+#else
+# define GCC_VERSION 0
+#endif
+#if defined(_MSC_VER) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define MSVC_VERSION _MSC_VER
+#else
+# define MSVC_VERSION 0
+#endif
+
+/*
+** Some C99 functions in "math.h" are only present for MSVC when its version
+** is associated with Visual Studio 2013 or higher.
+*/
+#ifndef SQLITE_HAVE_C99_MATH_FUNCS
+# if MSVC_VERSION==0 || MSVC_VERSION>=1800
+#  define SQLITE_HAVE_C99_MATH_FUNCS (1)
+# else
+#  define SQLITE_HAVE_C99_MATH_FUNCS (0)
+# endif
+#endif
+
+/* Needed for various definitions... */
+#if defined(__GNUC__) && !defined(_GNU_SOURCE)
+# define _GNU_SOURCE
+#endif
+
+#if defined(__OpenBSD__) && !defined(_BSD_SOURCE)
+# define _BSD_SOURCE
+#endif
+
+/*
+** Macro to disable warnings about missing "break" at the end of a "case".
+*/
+#if defined(__has_attribute)
+#  if __has_attribute(fallthrough)
+#    define deliberate_fall_through __attribute__((fallthrough));
+#  endif
+#endif
+#if !defined(deliberate_fall_through)
+#  define deliberate_fall_through
+#endif
+
+/*
+** For MinGW, check to see if we can include the header file containing its
+** version information, among other things.  Normally, this internal MinGW
+** header file would [only] be included automatically by other MinGW header
+** files; however, the contained version information is now required by this
+** header file to work around binary compatibility issues (see below) and
+** this is the only known way to reliably obtain it.  This entire #if block
+** would be completely unnecessary if there was any other way of detecting
+** MinGW via their preprocessor (e.g. if they customized their GCC to define
+** some MinGW-specific macros).  When compiling for MinGW, either the
+** _HAVE_MINGW_H or _HAVE__MINGW_H (note the extra underscore) macro must be
+** defined; otherwise, detection of conditions specific to MinGW will be
+** disabled.
+*/
+#if defined(_HAVE_MINGW_H)
+# include "mingw.h"
+#elif defined(_HAVE__MINGW_H)
+# include "_mingw.h"
+#endif
+
+/*
+** For MinGW version 4.x (and higher), check to see if the _USE_32BIT_TIME_T
+** define is required to maintain binary compatibility with the MSVC runtime
+** library in use (e.g. for Windows XP).
+*/
+#if !defined(_USE_32BIT_TIME_T) && !defined(_USE_64BIT_TIME_T) && \
+    defined(_WIN32) && !defined(_WIN64) && \
+    defined(__MINGW_MAJOR_VERSION) && __MINGW_MAJOR_VERSION >= 4 && \
+    defined(__MSVCRT__)
+# define _USE_32BIT_TIME_T
+#endif
+
+/* Optionally #include a user-defined header, whereby compilation options
+** may be set prior to where they take effect, but after platform setup.
+** If SQLITE_CUSTOM_INCLUDE=? is defined, its value names the #include
+** file.
+*/
+#ifdef SQLITE_CUSTOM_INCLUDE
+# define INC_STRINGIFY_(f) #f
+# define INC_STRINGIFY(f) INC_STRINGIFY_(f)
+# include INC_STRINGIFY(SQLITE_CUSTOM_INCLUDE)
+#endif
+
+/* The public SQLite interface.  The _FILE_OFFSET_BITS macro must appear
+** first in QNX.  Also, the _USE_32BIT_TIME_T macro must appear first for
+** MinGW.
+*/
+/************** Include sqlite3.h in the middle of sqliteInt.h ***************/
+/************** Begin file sqlite3.h *****************************************/
+/*
+** 2001-09-15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the SQLite library
+** presents to client programs.  If a C-function, structure, datatype,
+** or constant definition does not appear in this file, then it is
+** not a published API of SQLite, is subject to change without
+** notice, and should not be referenced by programs that use SQLite.
+**
+** Some of the definitions that are in this file are marked as
+** "experimental".  Experimental interfaces are normally new
+** features recently added to SQLite.  We do not anticipate changes
+** to experimental interfaces but reserve the right to make minor changes
+** if experience from use "in the wild" suggest such changes are prudent.
+**
+** The official C-language API documentation for SQLite is derived
+** from comments in this file.  This file is the authoritative source
+** on how SQLite interfaces are supposed to operate.
+**
+** The name of this file under configuration management is "sqlite.h.in".
+** The makefile makes some minor changes to this file (such as inserting
+** the version number) and changes its name to "sqlite3.h" as
+** part of the build process.
+*/
+#ifndef SQLITE3_H
+#define SQLITE3_H
+#include <stdarg.h>     /* Needed for the definition of va_list */
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#if 0
+extern "C" {
+#endif
+
+
+/*
+** Facilitate override of interface linkage and calling conventions.
+** Be aware that these macros may not be used within this particular
+** translation of the amalgamation and its associated header file.
+**
+** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
+** compiler that the target identifier should have external linkage.
+**
+** The SQLITE_CDECL macro is used to set the calling convention for
+** public functions that accept a variable number of arguments.
+**
+** The SQLITE_APICALL macro is used to set the calling convention for
+** public functions that accept a fixed number of arguments.
+**
+** The SQLITE_STDCALL macro is no longer used and is now deprecated.
+**
+** The SQLITE_CALLBACK macro is used to set the calling convention for
+** function pointers.
+**
+** The SQLITE_SYSAPI macro is used to set the calling convention for
+** functions provided by the operating system.
+**
+** Currently, the SQLITE_CDECL, SQLITE_APICALL, SQLITE_CALLBACK, and
+** SQLITE_SYSAPI macros are used only when building for environments
+** that require non-default calling conventions.
+*/
+#ifndef SQLITE_EXTERN
+# define SQLITE_EXTERN extern
+#endif
+#ifndef SQLITE_API
+# define SQLITE_API
+#endif
+#ifndef SQLITE_CDECL
+# define SQLITE_CDECL
+#endif
+#ifndef SQLITE_APICALL
+# define SQLITE_APICALL
+#endif
+#ifndef SQLITE_STDCALL
+# define SQLITE_STDCALL SQLITE_APICALL
+#endif
+#ifndef SQLITE_CALLBACK
+# define SQLITE_CALLBACK
+#endif
+#ifndef SQLITE_SYSAPI
+# define SQLITE_SYSAPI
+#endif
+
+/*
+** These no-op macros are used in front of interfaces to mark those
+** interfaces as either deprecated or experimental.  New applications
+** should not use deprecated interfaces - they are supported for backwards
+** compatibility only.  Application writers should be aware that
+** experimental interfaces are subject to change in point releases.
+**
+** These macros used to resolve to various kinds of compiler magic that
+** would generate warning messages when they were used.  But that
+** compiler magic ended up generating such a flurry of bug reports
+** that we have taken it all out and gone back to using simple
+** noop macros.
+*/
+#define SQLITE_DEPRECATED
+#define SQLITE_EXPERIMENTAL
+
+/*
+** Ensure these symbols were not defined by some previous header file.
+*/
+#ifdef SQLITE_VERSION
+# undef SQLITE_VERSION
+#endif
+#ifdef SQLITE_VERSION_NUMBER
+# undef SQLITE_VERSION_NUMBER
+#endif
+
+/*
+** CAPI3REF: Compile-Time Library Version Numbers
+**
+** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
+** evaluates to a string literal that is the SQLite version in the
+** format "X.Y.Z" where X is the major version number (always 3 for
+** SQLite3) and Y is the minor version number and Z is the release number.)^
+** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
+** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
+** numbers used in [SQLITE_VERSION].)^
+** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
+** be larger than the release from which it is derived.  Either Y will
+** be held constant and Z will be incremented or else Y will be incremented
+** and Z will be reset to zero.
+**
+** Since [version 3.6.18] ([dateof:3.6.18]),
+** SQLite source code has been stored in the
+** <a href="http://www.fossil-scm.org/">Fossil configuration management
+** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
+** a string which identifies a particular check-in of SQLite
+** within its configuration management system.  ^The SQLITE_SOURCE_ID
+** string contains the date and time of the check-in (UTC) and a SHA1
+** or SHA3-256 hash of the entire source tree.  If the source code has
+** been edited in any way since it was last checked in, then the last
+** four hexadecimal digits of the hash may be modified.
+**
+** See also: [sqlite3_libversion()],
+** [sqlite3_libversion_number()], [sqlite3_sourceid()],
+** [sqlite_version()] and [sqlite_source_id()].
+*/
+#define SQLITE_VERSION        "3.49.2"
+#define SQLITE_VERSION_NUMBER 3049002
+#define SQLITE_SOURCE_ID      "2025-05-07 10:39:52 17144570b0d96ae63cd6f3edca39e27ebd74925252bbaf6723bcb2f6b4861fb1"
+
+/*
+** CAPI3REF: Run-Time Library Version Numbers
+** KEYWORDS: sqlite3_version sqlite3_sourceid
+**
+** These interfaces provide the same information as the [SQLITE_VERSION],
+** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
+** but are associated with the library instead of the header file.  ^(Cautious
+** programmers might include assert() statements in their application to
+** verify that values returned by these interfaces match the macros in
+** the header, and thus ensure that the application is
+** compiled with matching library and header files.
+**
+** <blockquote><pre>
+** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
+** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
+** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
+** </pre></blockquote>)^
+**
+** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
+** macro.  ^The sqlite3_libversion() function returns a pointer to the
+** to the sqlite3_version[] string constant.  The sqlite3_libversion()
+** function is provided for use in DLLs since DLL users usually do not have
+** direct access to string constants within the DLL.  ^The
+** sqlite3_libversion_number() function returns an integer equal to
+** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns
+** a pointer to a string constant whose value is the same as the
+** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
+** using an edited copy of [the amalgamation], then the last four characters
+** of the hash might be different from [SQLITE_SOURCE_ID].)^
+**
+** See also: [sqlite_version()] and [sqlite_source_id()].
+*/
+SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
+SQLITE_API const char *sqlite3_libversion(void);
+SQLITE_API const char *sqlite3_sourceid(void);
+SQLITE_API int sqlite3_libversion_number(void);
+
+/*
+** CAPI3REF: Run-Time Library Compilation Options Diagnostics
+**
+** ^The sqlite3_compileoption_used() function returns 0 or 1
+** indicating whether the specified option was defined at
+** compile time.  ^The SQLITE_ prefix may be omitted from the
+** option name passed to sqlite3_compileoption_used().
+**
+** ^The sqlite3_compileoption_get() function allows iterating
+** over the list of options that were defined at compile time by
+** returning the N-th compile time option string.  ^If N is out of range,
+** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
+** prefix is omitted from any strings returned by
+** sqlite3_compileoption_get().
+**
+** ^Support for the diagnostic functions sqlite3_compileoption_used()
+** and sqlite3_compileoption_get() may be omitted by specifying the
+** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
+**
+** See also: SQL functions [sqlite_compileoption_used()] and
+** [sqlite_compileoption_get()] and the [compile_options pragma].
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
+SQLITE_API const char *sqlite3_compileoption_get(int N);
+#else
+# define sqlite3_compileoption_used(X) 0
+# define sqlite3_compileoption_get(X)  ((void*)0)
+#endif
+
+/*
+** CAPI3REF: Test To See If The Library Is Threadsafe
+**
+** ^The sqlite3_threadsafe() function returns zero if and only if
+** SQLite was compiled with mutexing code omitted due to the
+** [SQLITE_THREADSAFE] compile-time option being set to 0.
+**
+** SQLite can be compiled with or without mutexes.  When
+** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
+** are enabled and SQLite is threadsafe.  When the
+** [SQLITE_THREADSAFE] macro is 0,
+** the mutexes are omitted.  Without the mutexes, it is not safe
+** to use SQLite concurrently from more than one thread.
+**
+** Enabling mutexes incurs a measurable performance penalty.
+** So if speed is of utmost importance, it makes sense to disable
+** the mutexes.  But for maximum safety, mutexes should be enabled.
+** ^The default behavior is for mutexes to be enabled.
+**
+** This interface can be used by an application to make sure that the
+** version of SQLite that it is linking against was compiled with
+** the desired setting of the [SQLITE_THREADSAFE] macro.
+**
+** This interface only reports on the compile-time mutex setting
+** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
+** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
+** can be fully or partially disabled using a call to [sqlite3_config()]
+** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
+** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
+** sqlite3_threadsafe() function shows only the compile-time setting of
+** thread safety, not any run-time changes to that setting made by
+** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
+** is unchanged by calls to sqlite3_config().)^
+**
+** See the [threading mode] documentation for additional information.
+*/
+SQLITE_API int sqlite3_threadsafe(void);
+
+/*
+** CAPI3REF: Database Connection Handle
+** KEYWORDS: {database connection} {database connections}
+**
+** Each open SQLite database is represented by a pointer to an instance of
+** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
+** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
+** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
+** and [sqlite3_close_v2()] are its destructors.  There are many other
+** interfaces (such as
+** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
+** [sqlite3_busy_timeout()] to name but three) that are methods on an
+** sqlite3 object.
+*/
+typedef struct sqlite3 sqlite3;
+
+/*
+** CAPI3REF: 64-Bit Integer Types
+** KEYWORDS: sqlite_int64 sqlite_uint64
+**
+** Because there is no cross-platform way to specify 64-bit integer types
+** SQLite includes typedefs for 64-bit signed and unsigned integers.
+**
+** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
+** The sqlite_int64 and sqlite_uint64 types are supported for backwards
+** compatibility only.
+**
+** ^The sqlite3_int64 and sqlite_int64 types can store integer values
+** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
+** sqlite3_uint64 and sqlite_uint64 types can store integer values
+** between 0 and +18446744073709551615 inclusive.
+*/
+#ifdef SQLITE_INT64_TYPE
+  typedef SQLITE_INT64_TYPE sqlite_int64;
+# ifdef SQLITE_UINT64_TYPE
+    typedef SQLITE_UINT64_TYPE sqlite_uint64;
+# else
+    typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
+# endif
+#elif defined(_MSC_VER) || defined(__BORLANDC__)
+  typedef __int64 sqlite_int64;
+  typedef unsigned __int64 sqlite_uint64;
+#else
+  typedef long long int sqlite_int64;
+  typedef unsigned long long int sqlite_uint64;
+#endif
+typedef sqlite_int64 sqlite3_int64;
+typedef sqlite_uint64 sqlite3_uint64;
+
+/*
+** If compiling for a processor that lacks floating point support,
+** substitute integer for floating-point.
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define double sqlite3_int64
+#endif
+
+/*
+** CAPI3REF: Closing A Database Connection
+** DESTRUCTOR: sqlite3
+**
+** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
+** for the [sqlite3] object.
+** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
+** the [sqlite3] object is successfully destroyed and all associated
+** resources are deallocated.
+**
+** Ideally, applications should [sqlite3_finalize | finalize] all
+** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
+** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
+** with the [sqlite3] object prior to attempting to close the object.
+** ^If the database connection is associated with unfinalized prepared
+** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
+** sqlite3_close() will leave the database connection open and return
+** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
+** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
+** it returns [SQLITE_OK] regardless, but instead of deallocating the database
+** connection immediately, it marks the database connection as an unusable
+** "zombie" and makes arrangements to automatically deallocate the database
+** connection after all prepared statements are finalized, all BLOB handles
+** are closed, and all backups have finished. The sqlite3_close_v2() interface
+** is intended for use with host languages that are garbage collected, and
+** where the order in which destructors are called is arbitrary.
+**
+** ^If an [sqlite3] object is destroyed while a transaction is open,
+** the transaction is automatically rolled back.
+**
+** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
+** must be either a NULL
+** pointer or an [sqlite3] object pointer obtained
+** from [sqlite3_open()], [sqlite3_open16()], or
+** [sqlite3_open_v2()], and not previously closed.
+** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
+** argument is a harmless no-op.
+*/
+SQLITE_API int sqlite3_close(sqlite3*);
+SQLITE_API int sqlite3_close_v2(sqlite3*);
+
+/*
+** The type for a callback function.
+** This is legacy and deprecated.  It is included for historical
+** compatibility and is not documented.
+*/
+typedef int (*sqlite3_callback)(void*,int,char**, char**);
+
+/*
+** CAPI3REF: One-Step Query Execution Interface
+** METHOD: sqlite3
+**
+** The sqlite3_exec() interface is a convenience wrapper around
+** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
+** that allows an application to run multiple statements of SQL
+** without having to use a lot of C code.
+**
+** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
+** semicolon-separate SQL statements passed into its 2nd argument,
+** in the context of the [database connection] passed in as its 1st
+** argument.  ^If the callback function of the 3rd argument to
+** sqlite3_exec() is not NULL, then it is invoked for each result row
+** coming out of the evaluated SQL statements.  ^The 4th argument to
+** sqlite3_exec() is relayed through to the 1st argument of each
+** callback invocation.  ^If the callback pointer to sqlite3_exec()
+** is NULL, then no callback is ever invoked and result rows are
+** ignored.
+**
+** ^If an error occurs while evaluating the SQL statements passed into
+** sqlite3_exec(), then execution of the current statement stops and
+** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
+** is not NULL then any error message is written into memory obtained
+** from [sqlite3_malloc()] and passed back through the 5th parameter.
+** To avoid memory leaks, the application should invoke [sqlite3_free()]
+** on error message strings returned through the 5th parameter of
+** sqlite3_exec() after the error message string is no longer needed.
+** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
+** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
+** NULL before returning.
+**
+** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
+** routine returns SQLITE_ABORT without invoking the callback again and
+** without running any subsequent SQL statements.
+**
+** ^The 2nd argument to the sqlite3_exec() callback function is the
+** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
+** callback is an array of pointers to strings obtained as if from
+** [sqlite3_column_text()], one for each column.  ^If an element of a
+** result row is NULL then the corresponding string pointer for the
+** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
+** sqlite3_exec() callback is an array of pointers to strings where each
+** entry represents the name of corresponding result column as obtained
+** from [sqlite3_column_name()].
+**
+** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
+** to an empty string, or a pointer that contains only whitespace and/or
+** SQL comments, then no SQL statements are evaluated and the database
+** is not changed.
+**
+** Restrictions:
+**
+** <ul>
+** <li> The application must ensure that the 1st parameter to sqlite3_exec()
+**      is a valid and open [database connection].
+** <li> The application must not close the [database connection] specified by
+**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not modify the SQL statement text passed into
+**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not dereference the arrays or string pointers
+**       passed as the 3rd and 4th callback parameters after it returns.
+** </ul>
+*/
+SQLITE_API int sqlite3_exec(
+  sqlite3*,                                  /* An open database */
+  const char *sql,                           /* SQL to be evaluated */
+  int (*callback)(void*,int,char**,char**),  /* Callback function */
+  void *,                                    /* 1st argument to callback */
+  char **errmsg                              /* Error msg written here */
+);
+
+/*
+** CAPI3REF: Result Codes
+** KEYWORDS: {result code definitions}
+**
+** Many SQLite functions return an integer result code from the set shown
+** here in order to indicate success or failure.
+**
+** New error codes may be added in future versions of SQLite.
+**
+** See also: [extended result code definitions]
+*/
+#define SQLITE_OK           0   /* Successful result */
+/* beginning-of-error-codes */
+#define SQLITE_ERROR        1   /* Generic error */
+#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
+#define SQLITE_PERM         3   /* Access permission denied */
+#define SQLITE_ABORT        4   /* Callback routine requested an abort */
+#define SQLITE_BUSY         5   /* The database file is locked */
+#define SQLITE_LOCKED       6   /* A table in the database is locked */
+#define SQLITE_NOMEM        7   /* A malloc() failed */
+#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
+#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
+#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
+#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
+#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
+#define SQLITE_FULL        13   /* Insertion failed because database is full */
+#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
+#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
+#define SQLITE_EMPTY       16   /* Internal use only */
+#define SQLITE_SCHEMA      17   /* The database schema changed */
+#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
+#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
+#define SQLITE_MISMATCH    20   /* Data type mismatch */
+#define SQLITE_MISUSE      21   /* Library used incorrectly */
+#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
+#define SQLITE_AUTH        23   /* Authorization denied */
+#define SQLITE_FORMAT      24   /* Not used */
+#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
+#define SQLITE_NOTADB      26   /* File opened that is not a database file */
+#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
+#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
+#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
+#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
+/* end-of-error-codes */
+
+/*
+** CAPI3REF: Extended Result Codes
+** KEYWORDS: {extended result code definitions}
+**
+** In its default configuration, SQLite API routines return one of 30 integer
+** [result codes].  However, experience has shown that many of
+** these result codes are too coarse-grained.  They do not provide as
+** much information about problems as programmers might like.  In an effort to
+** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
+** and later) include
+** support for additional result codes that provide more detailed information
+** about errors. These [extended result codes] are enabled or disabled
+** on a per database connection basis using the
+** [sqlite3_extended_result_codes()] API.  Or, the extended code for
+** the most recent error can be obtained using
+** [sqlite3_extended_errcode()].
+*/
+#define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
+#define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
+#define SQLITE_ERROR_SNAPSHOT          (SQLITE_ERROR | (3<<8))
+#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
+#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
+#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
+#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
+#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
+#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
+#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
+#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
+#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
+#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
+#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
+#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
+#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
+#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
+#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
+#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
+#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
+#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
+#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
+#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
+#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
+#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
+#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
+#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
+#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
+#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
+#define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
+#define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
+#define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
+#define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
+#define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
+#define SQLITE_IOERR_DATA              (SQLITE_IOERR | (32<<8))
+#define SQLITE_IOERR_CORRUPTFS         (SQLITE_IOERR | (33<<8))
+#define SQLITE_IOERR_IN_PAGE           (SQLITE_IOERR | (34<<8))
+#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
+#define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
+#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
+#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
+#define SQLITE_BUSY_TIMEOUT            (SQLITE_BUSY   |  (3<<8))
+#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
+#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
+#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
+#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
+#define SQLITE_CANTOPEN_DIRTYWAL       (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
+#define SQLITE_CANTOPEN_SYMLINK        (SQLITE_CANTOPEN | (6<<8))
+#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
+#define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
+#define SQLITE_CORRUPT_INDEX           (SQLITE_CORRUPT | (3<<8))
+#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
+#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
+#define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
+#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
+#define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
+#define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
+#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
+#define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
+#define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
+#define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
+#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
+#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
+#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
+#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
+#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
+#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
+#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
+#define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
+#define SQLITE_CONSTRAINT_DATATYPE     (SQLITE_CONSTRAINT |(12<<8))
+#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
+#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
+#define SQLITE_NOTICE_RBU              (SQLITE_NOTICE | (3<<8))
+#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
+#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
+#define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
+#define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8)) /* internal use only */
+
+/*
+** CAPI3REF: Flags For File Open Operations
+**
+** These bit values are intended for use in the
+** 3rd parameter to the [sqlite3_open_v2()] interface and
+** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
+**
+** Only those flags marked as "Ok for sqlite3_open_v2()" may be
+** used as the third argument to the [sqlite3_open_v2()] interface.
+** The other flags have historically been ignored by sqlite3_open_v2(),
+** though future versions of SQLite might change so that an error is
+** raised if any of the disallowed bits are passed into sqlite3_open_v2().
+** Applications should not depend on the historical behavior.
+**
+** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
+** [sqlite3_open_v2()] does *not* cause the underlying database file
+** to be opened using O_EXCL.  Passing SQLITE_OPEN_EXCLUSIVE into
+** [sqlite3_open_v2()] has historically be a no-op and might become an
+** error in future versions of SQLite.
+*/
+#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
+#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
+#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
+#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
+#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
+#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
+#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
+#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
+#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
+#define SQLITE_OPEN_SUPER_JOURNAL    0x00004000  /* VFS only */
+#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
+#define SQLITE_OPEN_NOFOLLOW         0x01000000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_EXRESCODE        0x02000000  /* Extended result codes */
+
+/* Reserved:                         0x00F00000 */
+/* Legacy compatibility: */
+#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
+
+
+/*
+** CAPI3REF: Device Characteristics
+**
+** The xDeviceCharacteristics method of the [sqlite3_io_methods]
+** object returns an integer which is a vector of these
+** bit values expressing I/O characteristics of the mass storage
+** device that holds the file that the [sqlite3_io_methods]
+** refers to.
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
+** after reboot following a crash or power loss, the only bytes in a
+** file that were written at the application level might have changed
+** and that adjacent bytes, even bytes within the same sector are
+** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
+** flag indicates that a file cannot be deleted when open.  The
+** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
+** read-only media and cannot be changed even by processes with
+** elevated privileges.
+**
+** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
+** filesystem supports doing multiple write operations atomically when those
+** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
+** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
+**
+** The SQLITE_IOCAP_SUBPAGE_READ property means that it is ok to read
+** from the database file in amounts that are not a multiple of the
+** page size and that do not begin at a page boundary.  Without this
+** property, SQLite is careful to only do full-page reads and write
+** on aligned pages, with the one exception that it will do a sub-page
+** read of the first page to access the database header.
+*/
+#define SQLITE_IOCAP_ATOMIC                 0x00000001
+#define SQLITE_IOCAP_ATOMIC512              0x00000002
+#define SQLITE_IOCAP_ATOMIC1K               0x00000004
+#define SQLITE_IOCAP_ATOMIC2K               0x00000008
+#define SQLITE_IOCAP_ATOMIC4K               0x00000010
+#define SQLITE_IOCAP_ATOMIC8K               0x00000020
+#define SQLITE_IOCAP_ATOMIC16K              0x00000040
+#define SQLITE_IOCAP_ATOMIC32K              0x00000080
+#define SQLITE_IOCAP_ATOMIC64K              0x00000100
+#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
+#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
+#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
+#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
+#define SQLITE_IOCAP_IMMUTABLE              0x00002000
+#define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
+#define SQLITE_IOCAP_SUBPAGE_READ           0x00008000
+
+/*
+** CAPI3REF: File Locking Levels
+**
+** SQLite uses one of these integer values as the second
+** argument to calls it makes to the xLock() and xUnlock() methods
+** of an [sqlite3_io_methods] object.  These values are ordered from
+** lest restrictive to most restrictive.
+**
+** The argument to xLock() is always SHARED or higher.  The argument to
+** xUnlock is either SHARED or NONE.
+*/
+#define SQLITE_LOCK_NONE          0       /* xUnlock() only */
+#define SQLITE_LOCK_SHARED        1       /* xLock() or xUnlock() */
+#define SQLITE_LOCK_RESERVED      2       /* xLock() only */
+#define SQLITE_LOCK_PENDING       3       /* xLock() only */
+#define SQLITE_LOCK_EXCLUSIVE     4       /* xLock() only */
+
+/*
+** CAPI3REF: Synchronization Type Flags
+**
+** When SQLite invokes the xSync() method of an
+** [sqlite3_io_methods] object it uses a combination of
+** these integer values as the second argument.
+**
+** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
+** sync operation only needs to flush data to mass storage.  Inode
+** information need not be flushed. If the lower four bits of the flag
+** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
+** If the lower four bits equal SQLITE_SYNC_FULL, that means
+** to use Mac OS X style fullsync instead of fsync().
+**
+** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
+** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
+** settings.  The [synchronous pragma] determines when calls to the
+** xSync VFS method occur and applies uniformly across all platforms.
+** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
+** energetic or rigorous or forceful the sync operations are and
+** only make a difference on Mac OSX for the default SQLite code.
+** (Third-party VFS implementations might also make the distinction
+** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
+** operating systems natively supported by SQLite, only Mac OSX
+** cares about the difference.)
+*/
+#define SQLITE_SYNC_NORMAL        0x00002
+#define SQLITE_SYNC_FULL          0x00003
+#define SQLITE_SYNC_DATAONLY      0x00010
+
+/*
+** CAPI3REF: OS Interface Open File Handle
+**
+** An [sqlite3_file] object represents an open file in the
+** [sqlite3_vfs | OS interface layer].  Individual OS interface
+** implementations will
+** want to subclass this object by appending additional fields
+** for their own use.  The pMethods entry is a pointer to an
+** [sqlite3_io_methods] object that defines methods for performing
+** I/O operations on the open file.
+*/
+typedef struct sqlite3_file sqlite3_file;
+struct sqlite3_file {
+  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
+};
+
+/*
+** CAPI3REF: OS Interface File Virtual Methods Object
+**
+** Every file opened by the [sqlite3_vfs.xOpen] method populates an
+** [sqlite3_file] object (or, more commonly, a subclass of the
+** [sqlite3_file] object) with a pointer to an instance of this object.
+** This object defines the methods used to perform various operations
+** against the open file represented by the [sqlite3_file] object.
+**
+** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
+** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
+** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
+** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
+** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
+** to NULL.
+**
+** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
+** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
+** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
+** flag may be ORed in to indicate that only the data of the file
+** and not its inode needs to be synced.
+**
+** The integer values to xLock() and xUnlock() are one of
+** <ul>
+** <li> [SQLITE_LOCK_NONE],
+** <li> [SQLITE_LOCK_SHARED],
+** <li> [SQLITE_LOCK_RESERVED],
+** <li> [SQLITE_LOCK_PENDING], or
+** <li> [SQLITE_LOCK_EXCLUSIVE].
+** </ul>
+** xLock() upgrades the database file lock.  In other words, xLock() moves the
+** database file lock in the direction NONE toward EXCLUSIVE. The argument to
+** xLock() is always one of SHARED, RESERVED, PENDING, or EXCLUSIVE, never
+** SQLITE_LOCK_NONE.  If the database file lock is already at or above the
+** requested lock, then the call to xLock() is a no-op.
+** xUnlock() downgrades the database file lock to either SHARED or NONE.
+** If the lock is already at or below the requested lock state, then the call
+** to xUnlock() is a no-op.
+** The xCheckReservedLock() method checks whether any database connection,
+** either in this process or in some other process, is holding a RESERVED,
+** PENDING, or EXCLUSIVE lock on the file.  It returns, via its output
+** pointer parameter, true if such a lock exists and false otherwise.
+**
+** The xFileControl() method is a generic interface that allows custom
+** VFS implementations to directly control an open file using the
+** [sqlite3_file_control()] interface.  The second "op" argument is an
+** integer opcode.  The third argument is a generic pointer intended to
+** point to a structure that may contain arguments or space in which to
+** write return values.  Potential uses for xFileControl() might be
+** functions to enable blocking locks with timeouts, to change the
+** locking strategy (for example to use dot-file locks), to inquire
+** about the status of a lock, or to break stale locks.  The SQLite
+** core reserves all opcodes less than 100 for its own use.
+** A [file control opcodes | list of opcodes] less than 100 is available.
+** Applications that define a custom xFileControl method should use opcodes
+** greater than 100 to avoid conflicts.  VFS implementations should
+** return [SQLITE_NOTFOUND] for file control opcodes that they do not
+** recognize.
+**
+** The xSectorSize() method returns the sector size of the
+** device that underlies the file.  The sector size is the
+** minimum write that can be performed without disturbing
+** other bytes in the file.  The xDeviceCharacteristics()
+** method returns a bit vector describing behaviors of the
+** underlying device:
+**
+** <ul>
+** <li> [SQLITE_IOCAP_ATOMIC]
+** <li> [SQLITE_IOCAP_ATOMIC512]
+** <li> [SQLITE_IOCAP_ATOMIC1K]
+** <li> [SQLITE_IOCAP_ATOMIC2K]
+** <li> [SQLITE_IOCAP_ATOMIC4K]
+** <li> [SQLITE_IOCAP_ATOMIC8K]
+** <li> [SQLITE_IOCAP_ATOMIC16K]
+** <li> [SQLITE_IOCAP_ATOMIC32K]
+** <li> [SQLITE_IOCAP_ATOMIC64K]
+** <li> [SQLITE_IOCAP_SAFE_APPEND]
+** <li> [SQLITE_IOCAP_SEQUENTIAL]
+** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
+** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
+** <li> [SQLITE_IOCAP_IMMUTABLE]
+** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
+** <li> [SQLITE_IOCAP_SUBPAGE_READ]
+** </ul>
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().
+**
+** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
+** in the unread portions of the buffer with zeros.  A VFS that
+** fails to zero-fill short reads might seem to work.  However,
+** failure to zero-fill short reads will eventually lead to
+** database corruption.
+*/
+typedef struct sqlite3_io_methods sqlite3_io_methods;
+struct sqlite3_io_methods {
+  int iVersion;
+  int (*xClose)(sqlite3_file*);
+  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
+  int (*xSync)(sqlite3_file*, int flags);
+  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
+  int (*xLock)(sqlite3_file*, int);
+  int (*xUnlock)(sqlite3_file*, int);
+  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
+  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
+  int (*xSectorSize)(sqlite3_file*);
+  int (*xDeviceCharacteristics)(sqlite3_file*);
+  /* Methods above are valid for version 1 */
+  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
+  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
+  void (*xShmBarrier)(sqlite3_file*);
+  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
+  /* Methods above are valid for version 2 */
+  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
+  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
+  /* Methods above are valid for version 3 */
+  /* Additional methods may be added in future releases */
+};
+
+/*
+** CAPI3REF: Standard File Control Opcodes
+** KEYWORDS: {file control opcodes} {file control opcode}
+**
+** These integer constants are opcodes for the xFileControl method
+** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
+** interface.
+**
+** <ul>
+** <li>[[SQLITE_FCNTL_LOCKSTATE]]
+** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
+** opcode causes the xFileControl method to write the current state of
+** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
+** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
+** into an integer that the pArg argument points to.
+** This capability is only available if SQLite is compiled with [SQLITE_DEBUG].
+**
+** <li>[[SQLITE_FCNTL_SIZE_HINT]]
+** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
+** layer a hint of how large the database file will grow to be during the
+** current transaction.  This hint is not guaranteed to be accurate but it
+** is often close.  The underlying VFS might choose to preallocate database
+** file space based on this hint in order to help writes to the database
+** file run faster.
+**
+** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
+** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
+** implements [sqlite3_deserialize()] to set an upper bound on the size
+** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
+** If the integer pointed to is negative, then it is filled in with the
+** current limit.  Otherwise the limit is set to the larger of the value
+** of the integer pointed to and the current database size.  The integer
+** pointed to is set to the new limit.
+**
+** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
+** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
+** extends and truncates the database file in chunks of a size specified
+** by the user. The fourth argument to [sqlite3_file_control()] should
+** point to an integer (type int) containing the new chunk-size to use
+** for the nominated database. Allocating database file space in large
+** chunks (say 1MB at a time), may reduce file-system fragmentation and
+** improve performance on some systems.
+**
+** <li>[[SQLITE_FCNTL_FILE_POINTER]]
+** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with a particular database
+** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
+**
+** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
+** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with the journal file (either
+** the [rollback journal] or the [write-ahead log]) for a particular database
+** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
+**
+** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
+** No longer in use.
+**
+** <li>[[SQLITE_FCNTL_SYNC]]
+** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
+** sent to the VFS immediately before the xSync method is invoked on a
+** database file descriptor. Or, if the xSync method is not invoked
+** because the user has configured SQLite with
+** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
+** of the xSync method. In most cases, the pointer argument passed with
+** this file-control is NULL. However, if the database file is being synced
+** as part of a multi-database commit, the argument points to a nul-terminated
+** string containing the transactions super-journal file name. VFSes that
+** do not need this signal should silently ignore this opcode. Applications
+** should not call [sqlite3_file_control()] with this opcode as doing so may
+** disrupt the operation of the specialized VFSes that do require it.
+**
+** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
+** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
+** and sent to the VFS after a transaction has been committed immediately
+** but before the database is unlocked. VFSes that do not need this signal
+** should silently ignore this opcode. Applications should not call
+** [sqlite3_file_control()] with this opcode as doing so may disrupt the
+** operation of the specialized VFSes that do require it.
+**
+** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
+** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
+** retry counts and intervals for certain disk I/O operations for the
+** windows [VFS] in order to provide robustness in the presence of
+** anti-virus programs.  By default, the windows VFS will retry file read,
+** file write, and file delete operations up to 10 times, with a delay
+** of 25 milliseconds before the first retry and with the delay increasing
+** by an additional 25 milliseconds with each subsequent retry.  This
+** opcode allows these two values (10 retries and 25 milliseconds of delay)
+** to be adjusted.  The values are changed for all database connections
+** within the same process.  The argument is a pointer to an array of two
+** integers where the first integer is the new retry count and the second
+** integer is the delay.  If either integer is negative, then the setting
+** is not changed but instead the prior value of that setting is written
+** into the array entry, allowing the current retry settings to be
+** interrogated.  The zDbName parameter is ignored.
+**
+** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
+** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
+** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
+** write ahead log ([WAL file]) and shared memory
+** files used for transaction control
+** are automatically deleted when the latest connection to the database
+** closes.  Setting persistent WAL mode causes those files to persist after
+** close.  Persisting the files is useful when other processes that do not
+** have write permission on the directory containing the database file want
+** to read the database file, as the WAL and shared memory files must exist
+** in order for the database to be readable.  The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
+** WAL mode.  If the integer is -1, then it is overwritten with the current
+** WAL persistence setting.
+**
+** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
+** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
+** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
+** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
+** xDeviceCharacteristics methods. The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
+** mode.  If the integer is -1, then it is overwritten with the current
+** zero-damage mode setting.
+**
+** <li>[[SQLITE_FCNTL_OVERWRITE]]
+** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
+** a write transaction to indicate that, unless it is rolled back for some
+** reason, the entire database file will be overwritten by the current
+** transaction. This is used by VACUUM operations.
+**
+** <li>[[SQLITE_FCNTL_VFSNAME]]
+** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
+** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
+** final bottom-level VFS are written into memory obtained from
+** [sqlite3_malloc()] and the result is stored in the char* variable
+** that the fourth parameter of [sqlite3_file_control()] points to.
+** The caller is responsible for freeing the memory when done.  As with
+** all file-control actions, there is no guarantee that this will actually
+** do anything.  Callers should initialize the char* variable to a NULL
+** pointer in case this file-control is not implemented.  This file-control
+** is intended for diagnostic use only.
+**
+** <li>[[SQLITE_FCNTL_VFS_POINTER]]
+** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
+** [VFSes] currently in use.  ^(The argument X in
+** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
+** of type "[sqlite3_vfs] **".  This opcodes will set *X
+** to a pointer to the top-level VFS.)^
+** ^When there are multiple VFS shims in the stack, this opcode finds the
+** upper-most shim only.
+**
+** <li>[[SQLITE_FCNTL_PRAGMA]]
+** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
+** file control is sent to the open [sqlite3_file] object corresponding
+** to the database file to which the pragma statement refers. ^The argument
+** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
+** pointers to strings (char**) in which the second element of the array
+** is the name of the pragma and the third element is the argument to the
+** pragma or NULL if the pragma has no argument.  ^The handler for an
+** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
+** of the char** argument point to a string obtained from [sqlite3_mprintf()]
+** or the equivalent and that string will become the result of the pragma or
+** the error message if the pragma fails. ^If the
+** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
+** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
+** file control returns [SQLITE_OK], then the parser assumes that the
+** VFS has handled the PRAGMA itself and the parser generates a no-op
+** prepared statement if result string is NULL, or that returns a copy
+** of the result string if the string is non-NULL.
+** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
+** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
+** that the VFS encountered an error while handling the [PRAGMA] and the
+** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
+** file control occurs at the beginning of pragma statement analysis and so
+** it is able to override built-in [PRAGMA] statements.
+**
+** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
+** ^The [SQLITE_FCNTL_BUSYHANDLER]
+** file-control may be invoked by SQLite on the database file handle
+** shortly after it is opened in order to provide a custom VFS with access
+** to the connection's busy-handler callback. The argument is of type (void**)
+** - an array of two (void *) values. The first (void *) actually points
+** to a function of type (int (*)(void *)). In order to invoke the connection's
+** busy-handler, this function should be invoked with the second (void *) in
+** the array as the only argument. If it returns non-zero, then the operation
+** should be retried. If it returns zero, the custom VFS should abandon the
+** current operation.
+**
+** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
+** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
+** to have SQLite generate a
+** temporary filename using the same algorithm that is followed to generate
+** temporary filenames for TEMP tables and other internal uses.  The
+** argument should be a char** which will be filled with the filename
+** written into memory obtained from [sqlite3_malloc()].  The caller should
+** invoke [sqlite3_free()] on the result to avoid a memory leak.
+**
+** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
+** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
+** maximum number of bytes that will be used for memory-mapped I/O.
+** The argument is a pointer to a value of type sqlite3_int64 that
+** is an advisory maximum number of bytes in the file to memory map.  The
+** pointer is overwritten with the old value.  The limit is not changed if
+** the value originally pointed to is negative, and so the current limit
+** can be queried by passing in a pointer to a negative number.  This
+** file-control is used internally to implement [PRAGMA mmap_size].
+**
+** <li>[[SQLITE_FCNTL_TRACE]]
+** The [SQLITE_FCNTL_TRACE] file control provides advisory information
+** to the VFS about what the higher layers of the SQLite stack are doing.
+** This file control is used by some VFS activity tracing [shims].
+** The argument is a zero-terminated string.  Higher layers in the
+** SQLite stack may generate instances of this file control if
+** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
+**
+** <li>[[SQLITE_FCNTL_HAS_MOVED]]
+** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
+** pointer to an integer and it writes a boolean into that integer depending
+** on whether or not the file has been renamed, moved, or deleted since it
+** was first opened.
+**
+** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
+** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
+** underlying native file handle associated with a file handle.  This file
+** control interprets its argument as a pointer to a native file handle and
+** writes the resulting value there.
+**
+** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
+** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
+** opcode causes the xFileControl method to swap the file handle with the one
+** pointed to by the pArg argument.  This capability is used during testing
+** and only needs to be supported when SQLITE_TEST is defined.
+**
+** <li>[[SQLITE_FCNTL_NULL_IO]]
+** The [SQLITE_FCNTL_NULL_IO] opcode sets the low-level file descriptor
+** or file handle for the [sqlite3_file] object such that it will no longer
+** read or write to the database file.
+**
+** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
+** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
+** be advantageous to block on the next WAL lock if the lock is not immediately
+** available.  The WAL subsystem issues this signal during rare
+** circumstances in order to fix a problem with priority inversion.
+** Applications should <em>not</em> use this file-control.
+**
+** <li>[[SQLITE_FCNTL_ZIPVFS]]
+** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
+** VFS should return SQLITE_NOTFOUND for this opcode.
+**
+** <li>[[SQLITE_FCNTL_RBU]]
+** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
+** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
+** this opcode.
+**
+** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
+** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
+** the file descriptor is placed in "batch write mode", which
+** means all subsequent write operations will be deferred and done
+** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
+** that do not support batch atomic writes will return SQLITE_NOTFOUND.
+** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
+** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
+** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
+** no VFS interface calls on the same [sqlite3_file] file descriptor
+** except for calls to the xWrite method and the xFileControl method
+** with [SQLITE_FCNTL_SIZE_HINT].
+**
+** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
+** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
+** operations since the previous successful call to
+** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
+** This file control returns [SQLITE_OK] if and only if the writes were
+** all performed successfully and have been committed to persistent storage.
+** ^Regardless of whether or not it is successful, this file control takes
+** the file descriptor out of batch write mode so that all subsequent
+** write operations are independent.
+** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
+** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
+**
+** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
+** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
+** operations since the previous successful call to
+** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
+** ^This file control takes the file descriptor out of batch write mode
+** so that all subsequent write operations are independent.
+** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
+** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
+**
+** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
+** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
+** to block for up to M milliseconds before failing when attempting to
+** obtain a file lock using the xLock or xShmLock methods of the VFS.
+** The parameter is a pointer to a 32-bit signed integer that contains
+** the value that M is to be set to. Before returning, the 32-bit signed
+** integer is overwritten with the previous value of M.
+**
+** <li>[[SQLITE_FCNTL_DATA_VERSION]]
+** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
+** a database file.  The argument is a pointer to a 32-bit unsigned integer.
+** The "data version" for the pager is written into the pointer.  The
+** "data version" changes whenever any change occurs to the corresponding
+** database file, either through SQL statements on the same database
+** connection or through transactions committed by separate database
+** connections possibly in other processes. The [sqlite3_total_changes()]
+** interface can be used to find if any database on the connection has changed,
+** but that interface responds to changes on TEMP as well as MAIN and does
+** not provide a mechanism to detect changes to MAIN only.  Also, the
+** [sqlite3_total_changes()] interface responds to internal changes only and
+** omits changes made by other database connections.  The
+** [PRAGMA data_version] command provides a mechanism to detect changes to
+** a single attached database that occur due to other database connections,
+** but omits changes implemented by the database connection on which it is
+** called.  This file control is the only mechanism to detect changes that
+** happen either internally or externally and that are associated with
+** a particular attached database.
+**
+** <li>[[SQLITE_FCNTL_CKPT_START]]
+** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
+** in wal mode before the client starts to copy pages from the wal
+** file to the database file.
+**
+** <li>[[SQLITE_FCNTL_CKPT_DONE]]
+** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
+** in wal mode after the client has finished copying pages from the wal
+** file to the database file, but before the *-shm file is updated to
+** record the fact that the pages have been checkpointed.
+**
+** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
+** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
+** whether or not there is a database client in another process with a wal-mode
+** transaction open on the database or not. It is only available on unix.The
+** (void*) argument passed with this file-control should be a pointer to a
+** value of type (int). The integer value is set to 1 if the database is a wal
+** mode database and there exists at least one client in another process that
+** currently has an SQL transaction open on the database. It is set to 0 if
+** the database is not a wal-mode db, or if there is no such connection in any
+** other process. This opcode cannot be used to detect transactions opened
+** by clients within the current process, only within other processes.
+**
+** <li>[[SQLITE_FCNTL_CKSM_FILE]]
+** The [SQLITE_FCNTL_CKSM_FILE] opcode is for use internally by the
+** [checksum VFS shim] only.
+**
+** <li>[[SQLITE_FCNTL_RESET_CACHE]]
+** If there is currently no transaction open on the database, and the
+** database is not a temp db, then the [SQLITE_FCNTL_RESET_CACHE] file-control
+** purges the contents of the in-memory page cache. If there is an open
+** transaction, or if the db is a temp-db, this opcode is a no-op, not an error.
+** </ul>
+*/
+#define SQLITE_FCNTL_LOCKSTATE               1
+#define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
+#define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
+#define SQLITE_FCNTL_LAST_ERRNO              4
+#define SQLITE_FCNTL_SIZE_HINT               5
+#define SQLITE_FCNTL_CHUNK_SIZE              6
+#define SQLITE_FCNTL_FILE_POINTER            7
+#define SQLITE_FCNTL_SYNC_OMITTED            8
+#define SQLITE_FCNTL_WIN32_AV_RETRY          9
+#define SQLITE_FCNTL_PERSIST_WAL            10
+#define SQLITE_FCNTL_OVERWRITE              11
+#define SQLITE_FCNTL_VFSNAME                12
+#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
+#define SQLITE_FCNTL_PRAGMA                 14
+#define SQLITE_FCNTL_BUSYHANDLER            15
+#define SQLITE_FCNTL_TEMPFILENAME           16
+#define SQLITE_FCNTL_MMAP_SIZE              18
+#define SQLITE_FCNTL_TRACE                  19
+#define SQLITE_FCNTL_HAS_MOVED              20
+#define SQLITE_FCNTL_SYNC                   21
+#define SQLITE_FCNTL_COMMIT_PHASETWO        22
+#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
+#define SQLITE_FCNTL_WAL_BLOCK              24
+#define SQLITE_FCNTL_ZIPVFS                 25
+#define SQLITE_FCNTL_RBU                    26
+#define SQLITE_FCNTL_VFS_POINTER            27
+#define SQLITE_FCNTL_JOURNAL_POINTER        28
+#define SQLITE_FCNTL_WIN32_GET_HANDLE       29
+#define SQLITE_FCNTL_PDB                    30
+#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
+#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
+#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
+#define SQLITE_FCNTL_LOCK_TIMEOUT           34
+#define SQLITE_FCNTL_DATA_VERSION           35
+#define SQLITE_FCNTL_SIZE_LIMIT             36
+#define SQLITE_FCNTL_CKPT_DONE              37
+#define SQLITE_FCNTL_RESERVE_BYTES          38
+#define SQLITE_FCNTL_CKPT_START             39
+#define SQLITE_FCNTL_EXTERNAL_READER        40
+#define SQLITE_FCNTL_CKSM_FILE              41
+#define SQLITE_FCNTL_RESET_CACHE            42
+#define SQLITE_FCNTL_NULL_IO                43
+
+/* deprecated names */
+#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
+#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
+#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
+
+
+/*
+** CAPI3REF: Mutex Handle
+**
+** The mutex module within SQLite defines [sqlite3_mutex] to be an
+** abstract type for a mutex object.  The SQLite core never looks
+** at the internal representation of an [sqlite3_mutex].  It only
+** deals with pointers to the [sqlite3_mutex] object.
+**
+** Mutexes are created using [sqlite3_mutex_alloc()].
+*/
+typedef struct sqlite3_mutex sqlite3_mutex;
+
+/*
+** CAPI3REF: Loadable Extension Thunk
+**
+** A pointer to the opaque sqlite3_api_routines structure is passed as
+** the third parameter to entry points of [loadable extensions].  This
+** structure must be typedefed in order to work around compiler warnings
+** on some platforms.
+*/
+typedef struct sqlite3_api_routines sqlite3_api_routines;
+
+/*
+** CAPI3REF: File Name
+**
+** Type [sqlite3_filename] is used by SQLite to pass filenames to the
+** xOpen method of a [VFS]. It may be cast to (const char*) and treated
+** as a normal, nul-terminated, UTF-8 buffer containing the filename, but
+** may also be passed to special APIs such as:
+**
+** <ul>
+** <li>  sqlite3_filename_database()
+** <li>  sqlite3_filename_journal()
+** <li>  sqlite3_filename_wal()
+** <li>  sqlite3_uri_parameter()
+** <li>  sqlite3_uri_boolean()
+** <li>  sqlite3_uri_int64()
+** <li>  sqlite3_uri_key()
+** </ul>
+*/
+typedef const char *sqlite3_filename;
+
+/*
+** CAPI3REF: OS Interface Object
+**
+** An instance of the sqlite3_vfs object defines the interface between
+** the SQLite core and the underlying operating system.  The "vfs"
+** in the name of the object stands for "virtual file system".  See
+** the [VFS | VFS documentation] for further information.
+**
+** The VFS interface is sometimes extended by adding new methods onto
+** the end.  Each time such an extension occurs, the iVersion field
+** is incremented.  The iVersion value started out as 1 in
+** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
+** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
+** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
+** may be appended to the sqlite3_vfs object and the iVersion value
+** may increase again in future versions of SQLite.
+** Note that due to an oversight, the structure
+** of the sqlite3_vfs object changed in the transition from
+** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
+** and yet the iVersion field was not increased.
+**
+** The szOsFile field is the size of the subclassed [sqlite3_file]
+** structure used by this VFS.  mxPathname is the maximum length of
+** a pathname in this VFS.
+**
+** Registered sqlite3_vfs objects are kept on a linked list formed by
+** the pNext pointer.  The [sqlite3_vfs_register()]
+** and [sqlite3_vfs_unregister()] interfaces manage this list
+** in a thread-safe way.  The [sqlite3_vfs_find()] interface
+** searches the list.  Neither the application code nor the VFS
+** implementation should use the pNext pointer.
+**
+** The pNext field is the only field in the sqlite3_vfs
+** structure that SQLite will ever modify.  SQLite will only access
+** or modify this field while holding a particular static mutex.
+** The application should never modify anything within the sqlite3_vfs
+** object once the object has been registered.
+**
+** The zName field holds the name of the VFS module.  The name must
+** be unique across all VFS modules.
+**
+** [[sqlite3_vfs.xOpen]]
+** ^SQLite guarantees that the zFilename parameter to xOpen
+** is either a NULL pointer or string obtained
+** from xFullPathname() with an optional suffix added.
+** ^If a suffix is added to the zFilename parameter, it will
+** consist of a single "-" character followed by no more than
+** 11 alphanumeric and/or "-" characters.
+** ^SQLite further guarantees that
+** the string will be valid and unchanged until xClose() is
+** called. Because of the previous sentence,
+** the [sqlite3_file] can safely store a pointer to the
+** filename if it needs to remember the filename for some reason.
+** If the zFilename parameter to xOpen is a NULL pointer then xOpen
+** must invent its own temporary name for the file.  ^Whenever the
+** xFilename parameter is NULL it will also be the case that the
+** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
+**
+** The flags argument to xOpen() includes all bits set in
+** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
+** or [sqlite3_open16()] is used, then flags includes at least
+** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
+** If xOpen() opens a file read-only then it sets *pOutFlags to
+** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
+**
+** ^(SQLite will also add one of the following flags to the xOpen()
+** call, depending on the object being opened:
+**
+** <ul>
+** <li>  [SQLITE_OPEN_MAIN_DB]
+** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
+** <li>  [SQLITE_OPEN_TEMP_DB]
+** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
+** <li>  [SQLITE_OPEN_TRANSIENT_DB]
+** <li>  [SQLITE_OPEN_SUBJOURNAL]
+** <li>  [SQLITE_OPEN_SUPER_JOURNAL]
+** <li>  [SQLITE_OPEN_WAL]
+** </ul>)^
+**
+** The file I/O implementation can use the object type flags to
+** change the way it deals with files.  For example, an application
+** that does not care about crash recovery or rollback might make
+** the open of a journal file a no-op.  Writes to this journal would
+** also be no-ops, and any attempt to read the journal would return
+** SQLITE_IOERR.  Or the implementation might recognize that a database
+** file will be doing page-aligned sector reads and writes in a random
+** order and set up its I/O subsystem accordingly.
+**
+** SQLite might also add one of the following flags to the xOpen method:
+**
+** <ul>
+** <li> [SQLITE_OPEN_DELETEONCLOSE]
+** <li> [SQLITE_OPEN_EXCLUSIVE]
+** </ul>
+**
+** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
+** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
+** will be set for TEMP databases and their journals, transient
+** databases, and subjournals.
+**
+** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
+** with the [SQLITE_OPEN_CREATE] flag, which are both directly
+** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
+** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
+** SQLITE_OPEN_CREATE, is used to indicate that file should always
+** be created, and that it is an error if it already exists.
+** It is <i>not</i> used to indicate the file should be opened
+** for exclusive access.
+**
+** ^At least szOsFile bytes of memory are allocated by SQLite
+** to hold the [sqlite3_file] structure passed as the third
+** argument to xOpen.  The xOpen method does not have to
+** allocate the structure; it should just fill it in.  Note that
+** the xOpen method must set the sqlite3_file.pMethods to either
+** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
+** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
+** element will be valid after xOpen returns regardless of the success
+** or failure of the xOpen call.
+**
+** [[sqlite3_vfs.xAccess]]
+** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
+** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
+** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
+** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
+** flag is never actually used and is not implemented in the built-in
+** VFSes of SQLite.  The file is named by the second argument and can be a
+** directory. The xAccess method returns [SQLITE_OK] on success or some
+** non-zero error code if there is an I/O error or if the name of
+** the file given in the second argument is illegal.  If SQLITE_OK
+** is returned, then non-zero or zero is written into *pResOut to indicate
+** whether or not the file is accessible.
+**
+** ^SQLite will always allocate at least mxPathname+1 bytes for the
+** output buffer xFullPathname.  The exact size of the output buffer
+** is also passed as a parameter to both  methods. If the output buffer
+** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
+** handled as a fatal error by SQLite, vfs implementations should endeavor
+** to prevent this by setting mxPathname to a sufficiently large value.
+**
+** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
+** interfaces are not strictly a part of the filesystem, but they are
+** included in the VFS structure for completeness.
+** The xRandomness() function attempts to return nBytes bytes
+** of good-quality randomness into zOut.  The return value is
+** the actual number of bytes of randomness obtained.
+** The xSleep() method causes the calling thread to sleep for at
+** least the number of microseconds given.  ^The xCurrentTime()
+** method returns a Julian Day Number for the current date and time as
+** a floating point value.
+** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
+** Day Number multiplied by 86400000 (the number of milliseconds in
+** a 24-hour day).
+** ^SQLite will use the xCurrentTimeInt64() method to get the current
+** date and time if that method is available (if iVersion is 2 or
+** greater and the function pointer is not NULL) and will fall back
+** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
+**
+** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
+** are not used by the SQLite core.  These optional interfaces are provided
+** by some VFSes to facilitate testing of the VFS code. By overriding
+** system calls with functions under its control, a test program can
+** simulate faults and error conditions that would otherwise be difficult
+** or impossible to induce.  The set of system calls that can be overridden
+** varies from one VFS to another, and from one version of the same VFS to the
+** next.  Applications that use these interfaces must be prepared for any
+** or all of these interfaces to be NULL or for their behavior to change
+** from one release to the next.  Applications must not attempt to access
+** any of these methods if the iVersion of the VFS is less than 3.
+*/
+typedef struct sqlite3_vfs sqlite3_vfs;
+typedef void (*sqlite3_syscall_ptr)(void);
+struct sqlite3_vfs {
+  int iVersion;            /* Structure version number (currently 3) */
+  int szOsFile;            /* Size of subclassed sqlite3_file */
+  int mxPathname;          /* Maximum file pathname length */
+  sqlite3_vfs *pNext;      /* Next registered VFS */
+  const char *zName;       /* Name of this virtual file system */
+  void *pAppData;          /* Pointer to application-specific data */
+  int (*xOpen)(sqlite3_vfs*, sqlite3_filename zName, sqlite3_file*,
+               int flags, int *pOutFlags);
+  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
+  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
+  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
+  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
+  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
+  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
+  void (*xDlClose)(sqlite3_vfs*, void*);
+  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
+  int (*xSleep)(sqlite3_vfs*, int microseconds);
+  int (*xCurrentTime)(sqlite3_vfs*, double*);
+  int (*xGetLastError)(sqlite3_vfs*, int, char *);
+  /*
+  ** The methods above are in version 1 of the sqlite_vfs object
+  ** definition.  Those that follow are added in version 2 or later
+  */
+  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
+  /*
+  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
+  ** Those below are for version 3 and greater.
+  */
+  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
+  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
+  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
+  /*
+  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
+  ** New fields may be appended in future versions.  The iVersion
+  ** value will increment whenever this happens.
+  */
+};
+
+/*
+** CAPI3REF: Flags for the xAccess VFS method
+**
+** These integer constants can be used as the third parameter to
+** the xAccess method of an [sqlite3_vfs] object.  They determine
+** what kind of permissions the xAccess method is looking for.
+** With SQLITE_ACCESS_EXISTS, the xAccess method
+** simply checks whether the file exists.
+** With SQLITE_ACCESS_READWRITE, the xAccess method
+** checks whether the named directory is both readable and writable
+** (in other words, if files can be added, removed, and renamed within
+** the directory).
+** The SQLITE_ACCESS_READWRITE constant is currently used only by the
+** [temp_store_directory pragma], though this could change in a future
+** release of SQLite.
+** With SQLITE_ACCESS_READ, the xAccess method
+** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
+** currently unused, though it might be used in a future release of
+** SQLite.
+*/
+#define SQLITE_ACCESS_EXISTS    0
+#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
+#define SQLITE_ACCESS_READ      2   /* Unused */
+
+/*
+** CAPI3REF: Flags for the xShmLock VFS method
+**
+** These integer constants define the various locking operations
+** allowed by the xShmLock method of [sqlite3_io_methods].  The
+** following are the only legal combinations of flags to the
+** xShmLock method:
+**
+** <ul>
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
+** </ul>
+**
+** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
+** was given on the corresponding lock.
+**
+** The xShmLock method can transition between unlocked and SHARED or
+** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
+** and EXCLUSIVE.
+*/
+#define SQLITE_SHM_UNLOCK       1
+#define SQLITE_SHM_LOCK         2
+#define SQLITE_SHM_SHARED       4
+#define SQLITE_SHM_EXCLUSIVE    8
+
+/*
+** CAPI3REF: Maximum xShmLock index
+**
+** The xShmLock method on [sqlite3_io_methods] may use values
+** between 0 and this upper bound as its "offset" argument.
+** The SQLite core will never attempt to acquire or release a
+** lock outside of this range
+*/
+#define SQLITE_SHM_NLOCK        8
+
+
+/*
+** CAPI3REF: Initialize The SQLite Library
+**
+** ^The sqlite3_initialize() routine initializes the
+** SQLite library.  ^The sqlite3_shutdown() routine
+** deallocates any resources that were allocated by sqlite3_initialize().
+** These routines are designed to aid in process initialization and
+** shutdown on embedded systems.  Workstation applications using
+** SQLite normally do not need to invoke either of these routines.
+**
+** A call to sqlite3_initialize() is an "effective" call if it is
+** the first time sqlite3_initialize() is invoked during the lifetime of
+** the process, or if it is the first time sqlite3_initialize() is invoked
+** following a call to sqlite3_shutdown().  ^(Only an effective call
+** of sqlite3_initialize() does any initialization.  All other calls
+** are harmless no-ops.)^
+**
+** A call to sqlite3_shutdown() is an "effective" call if it is the first
+** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
+** an effective call to sqlite3_shutdown() does any deinitialization.
+** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
+**
+** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
+** is not.  The sqlite3_shutdown() interface must only be called from a
+** single thread.  All open [database connections] must be closed and all
+** other SQLite resources must be deallocated prior to invoking
+** sqlite3_shutdown().
+**
+** Among other things, ^sqlite3_initialize() will invoke
+** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
+** will invoke sqlite3_os_end().
+**
+** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
+** ^If for some reason, sqlite3_initialize() is unable to initialize
+** the library (perhaps it is unable to allocate a needed resource such
+** as a mutex) it returns an [error code] other than [SQLITE_OK].
+**
+** ^The sqlite3_initialize() routine is called internally by many other
+** SQLite interfaces so that an application usually does not need to
+** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
+** calls sqlite3_initialize() so the SQLite library will be automatically
+** initialized when [sqlite3_open()] is called if it has not be initialized
+** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
+** compile-time option, then the automatic calls to sqlite3_initialize()
+** are omitted and the application must call sqlite3_initialize() directly
+** prior to using any other SQLite interface.  For maximum portability,
+** it is recommended that applications always invoke sqlite3_initialize()
+** directly prior to using any other SQLite interface.  Future releases
+** of SQLite may require this.  In other words, the behavior exhibited
+** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
+** default behavior in some future release of SQLite.
+**
+** The sqlite3_os_init() routine does operating-system specific
+** initialization of the SQLite library.  The sqlite3_os_end()
+** routine undoes the effect of sqlite3_os_init().  Typical tasks
+** performed by these routines include allocation or deallocation
+** of static resources, initialization of global variables,
+** setting up a default [sqlite3_vfs] module, or setting up
+** a default configuration using [sqlite3_config()].
+**
+** The application should never invoke either sqlite3_os_init()
+** or sqlite3_os_end() directly.  The application should only invoke
+** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
+** interface is called automatically by sqlite3_initialize() and
+** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
+** implementations for sqlite3_os_init() and sqlite3_os_end()
+** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
+** When [custom builds | built for other platforms]
+** (using the [SQLITE_OS_OTHER=1] compile-time
+** option) the application must supply a suitable implementation for
+** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
+** implementation of sqlite3_os_init() or sqlite3_os_end()
+** must return [SQLITE_OK] on success and some other [error code] upon
+** failure.
+*/
+SQLITE_API int sqlite3_initialize(void);
+SQLITE_API int sqlite3_shutdown(void);
+SQLITE_API int sqlite3_os_init(void);
+SQLITE_API int sqlite3_os_end(void);
+
+/*
+** CAPI3REF: Configuring The SQLite Library
+**
+** The sqlite3_config() interface is used to make global configuration
+** changes to SQLite in order to tune SQLite to the specific needs of
+** the application.  The default configuration is recommended for most
+** applications and so this routine is usually not necessary.  It is
+** provided to support rare applications with unusual needs.
+**
+** <b>The sqlite3_config() interface is not threadsafe. The application
+** must ensure that no other SQLite interfaces are invoked by other
+** threads while sqlite3_config() is running.</b>
+**
+** The first argument to sqlite3_config() is an integer
+** [configuration option] that determines
+** what property of SQLite is to be configured.  Subsequent arguments
+** vary depending on the [configuration option]
+** in the first argument.
+**
+** For most configuration options, the sqlite3_config() interface
+** may only be invoked prior to library initialization using
+** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
+** The exceptional configuration options that may be invoked at any time
+** are called "anytime configuration options".
+** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
+** [sqlite3_shutdown()] with a first argument that is not an anytime
+** configuration option, then the sqlite3_config() call will return SQLITE_MISUSE.
+** Note, however, that ^sqlite3_config() can be called as part of the
+** implementation of an application-defined [sqlite3_os_init()].
+**
+** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
+** ^If the option is unknown or SQLite is unable to set the option
+** then this routine returns a non-zero [error code].
+*/
+SQLITE_API int sqlite3_config(int, ...);
+
+/*
+** CAPI3REF: Configure database connections
+** METHOD: sqlite3
+**
+** The sqlite3_db_config() interface is used to make configuration
+** changes to a [database connection].  The interface is similar to
+** [sqlite3_config()] except that the changes apply to a single
+** [database connection] (specified in the first argument).
+**
+** The second argument to sqlite3_db_config(D,V,...)  is the
+** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
+** that indicates what aspect of the [database connection] is being configured.
+** Subsequent arguments vary depending on the configuration verb.
+**
+** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
+** the call is considered successful.
+*/
+SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Memory Allocation Routines
+**
+** An instance of this object defines the interface between SQLite
+** and low-level memory allocation routines.
+**
+** This object is used in only one place in the SQLite interface.
+** A pointer to an instance of this object is the argument to
+** [sqlite3_config()] when the configuration option is
+** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
+** By creating an instance of this object
+** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
+** during configuration, an application can specify an alternative
+** memory allocation subsystem for SQLite to use for all of its
+** dynamic memory needs.
+**
+** Note that SQLite comes with several [built-in memory allocators]
+** that are perfectly adequate for the overwhelming majority of applications
+** and that this object is only useful to a tiny minority of applications
+** with specialized memory allocation requirements.  This object is
+** also used during testing of SQLite in order to specify an alternative
+** memory allocator that simulates memory out-of-memory conditions in
+** order to verify that SQLite recovers gracefully from such
+** conditions.
+**
+** The xMalloc, xRealloc, and xFree methods must work like the
+** malloc(), realloc() and free() functions from the standard C library.
+** ^SQLite guarantees that the second argument to
+** xRealloc is always a value returned by a prior call to xRoundup.
+**
+** xSize should return the allocated size of a memory allocation
+** previously obtained from xMalloc or xRealloc.  The allocated size
+** is always at least as big as the requested size but may be larger.
+**
+** The xRoundup method returns what would be the allocated size of
+** a memory allocation given a particular requested size.  Most memory
+** allocators round up memory allocations at least to the next multiple
+** of 8.  Some allocators round up to a larger multiple or to a power of 2.
+** Every memory allocation request coming in through [sqlite3_malloc()]
+** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
+** that causes the corresponding memory allocation to fail.
+**
+** The xInit method initializes the memory allocator.  For example,
+** it might allocate any required mutexes or initialize internal data
+** structures.  The xShutdown method is invoked (indirectly) by
+** [sqlite3_shutdown()] and should deallocate any resources acquired
+** by xInit.  The pAppData pointer is used as the only parameter to
+** xInit and xShutdown.
+**
+** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
+** the xInit method, so the xInit method need not be threadsafe.  The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  For all other methods, SQLite
+** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
+** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
+** it is by default) and so the methods are automatically serialized.
+** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
+** methods must be threadsafe or else make their own arrangements for
+** serialization.
+**
+** SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+*/
+typedef struct sqlite3_mem_methods sqlite3_mem_methods;
+struct sqlite3_mem_methods {
+  void *(*xMalloc)(int);         /* Memory allocation function */
+  void (*xFree)(void*);          /* Free a prior allocation */
+  void *(*xRealloc)(void*,int);  /* Resize an allocation */
+  int (*xSize)(void*);           /* Return the size of an allocation */
+  int (*xRoundup)(int);          /* Round up request size to allocation size */
+  int (*xInit)(void*);           /* Initialize the memory allocator */
+  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
+  void *pAppData;                /* Argument to xInit() and xShutdown() */
+};
+
+/*
+** CAPI3REF: Configuration Options
+** KEYWORDS: {configuration option}
+**
+** These constants are the available integer configuration options that
+** can be passed as the first argument to the [sqlite3_config()] interface.
+**
+** Most of the configuration options for sqlite3_config()
+** will only work if invoked prior to [sqlite3_initialize()] or after
+** [sqlite3_shutdown()].  The few exceptions to this rule are called
+** "anytime configuration options".
+** ^Calling [sqlite3_config()] with a first argument that is not an
+** anytime configuration option in between calls to [sqlite3_initialize()] and
+** [sqlite3_shutdown()] is a no-op that returns SQLITE_MISUSE.
+**
+** The set of anytime configuration options can change (by insertions
+** and/or deletions) from one release of SQLite to the next.
+** As of SQLite version 3.42.0, the complete set of anytime configuration
+** options is:
+** <ul>
+** <li> SQLITE_CONFIG_LOG
+** <li> SQLITE_CONFIG_PCACHE_HDRSZ
+** </ul>
+**
+** New configuration options may be added in future releases of SQLite.
+** Existing configuration options might be discontinued.  Applications
+** should check the return code from [sqlite3_config()] to make sure that
+** the call worked.  The [sqlite3_config()] interface will return a
+** non-zero [error code] if a discontinued or unsupported configuration option
+** is invoked.
+**
+** <dl>
+** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Single-thread.  In other words, it disables
+** all mutexing and puts SQLite into a mode where it can only be used
+** by a single thread.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to change the [threading mode] from its default
+** value of Single-thread and so [sqlite3_config()] will return
+** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
+** configuration option.</dd>
+**
+** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Multi-thread.  In other words, it disables
+** mutexing on [database connection] and [prepared statement] objects.
+** The application is responsible for serializing access to
+** [database connections] and [prepared statements].  But other mutexes
+** are enabled so that SQLite will be safe to use in a multi-threaded
+** environment as long as no two threads attempt to use the same
+** [database connection] at the same time.  ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Multi-thread [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
+**
+** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Serialized. In other words, this option enables
+** all mutexes including the recursive
+** mutexes on [database connection] and [prepared statement] objects.
+** In this mode (which is the default when SQLite is compiled with
+** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
+** to [database connections] and [prepared statements] so that the
+** application is free to use the same [database connection] or the
+** same [prepared statement] in different threads at the same time.
+** ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Serialized [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
+**
+** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
+** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
+** a pointer to an instance of the [sqlite3_mem_methods] structure.
+** The argument specifies
+** alternative low-level memory allocation routines to be used in place of
+** the memory allocation routines built into SQLite.)^ ^SQLite makes
+** its own private copy of the content of the [sqlite3_mem_methods] structure
+** before the [sqlite3_config()] call returns.</dd>
+**
+** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
+** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
+** is a pointer to an instance of the [sqlite3_mem_methods] structure.
+** The [sqlite3_mem_methods]
+** structure is filled with the currently defined memory allocation routines.)^
+** This option can be used to overload the default memory allocation
+** routines with a wrapper that simulations memory allocation failure or
+** tracks memory usage, for example. </dd>
+**
+** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
+** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
+** type int, interpreted as a boolean, which if true provides a hint to
+** SQLite that it should avoid large memory allocations if possible.
+** SQLite will run faster if it is free to make large memory allocations,
+** but some application might prefer to run slower in exchange for
+** guarantees about memory fragmentation that are possible if large
+** allocations are avoided.  This hint is normally off.
+** </dd>
+**
+** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
+** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
+** interpreted as a boolean, which enables or disables the collection of
+** memory allocation statistics. ^(When memory allocation statistics are
+** disabled, the following SQLite interfaces become non-operational:
+**   <ul>
+**   <li> [sqlite3_hard_heap_limit64()]
+**   <li> [sqlite3_memory_used()]
+**   <li> [sqlite3_memory_highwater()]
+**   <li> [sqlite3_soft_heap_limit64()]
+**   <li> [sqlite3_status64()]
+**   </ul>)^
+** ^Memory allocation statistics are enabled by default unless SQLite is
+** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
+** allocation statistics are disabled by default.
+** </dd>
+**
+** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
+** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
+** </dd>
+**
+** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
+** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
+** that SQLite can use for the database page cache with the default page
+** cache implementation.
+** This configuration option is a no-op if an application-defined page
+** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
+** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
+** 8-byte aligned memory (pMem), the size of each page cache line (sz),
+** and the number of cache lines (N).
+** The sz argument should be the size of the largest database page
+** (a power of two between 512 and 65536) plus some extra bytes for each
+** page header.  ^The number of extra bytes needed by the page header
+** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
+** ^It is harmless, apart from the wasted memory,
+** for the sz parameter to be larger than necessary.  The pMem
+** argument must be either a NULL pointer or a pointer to an 8-byte
+** aligned block of memory of at least sz*N bytes, otherwise
+** subsequent behavior is undefined.
+** ^When pMem is not NULL, SQLite will strive to use the memory provided
+** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
+** a page cache line is larger than sz bytes or if all of the pMem buffer
+** is exhausted.
+** ^If pMem is NULL and N is non-zero, then each database connection
+** does an initial bulk allocation for page cache memory
+** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
+** of -1024*N bytes if N is negative, . ^If additional
+** page cache memory is needed beyond what is provided by the initial
+** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
+** additional cache line. </dd>
+**
+** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
+** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
+** that SQLite will use for all of its dynamic memory allocation needs
+** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
+** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
+** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
+** [SQLITE_ERROR] if invoked otherwise.
+** ^There are three arguments to SQLITE_CONFIG_HEAP:
+** An 8-byte aligned pointer to the memory,
+** the number of bytes in the memory buffer, and the minimum allocation size.
+** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
+** to using its default memory allocator (the system malloc() implementation),
+** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
+** memory pointer is not NULL then the alternative memory
+** allocator is engaged to handle all of SQLites memory allocation needs.
+** The first pointer (the memory pointer) must be aligned to an 8-byte
+** boundary or subsequent behavior of SQLite will be undefined.
+** The minimum allocation size is capped at 2**12. Reasonable values
+** for the minimum allocation size are 2**5 through 2**8.</dd>
+**
+** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
+** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
+** pointer to an instance of the [sqlite3_mutex_methods] structure.
+** The argument specifies alternative low-level mutex routines to be used
+** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
+** the content of the [sqlite3_mutex_methods] structure before the call to
+** [sqlite3_config()] returns. ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
+**
+** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
+** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
+** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
+** [sqlite3_mutex_methods]
+** structure is filled with the currently defined mutex routines.)^
+** This option can be used to overload the default mutex allocation
+** routines with a wrapper used to track mutex usage for performance
+** profiling or testing, for example.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
+**
+** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
+** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
+** the default size of lookaside memory on each [database connection].
+** The first argument is the
+** size of each lookaside buffer slot and the second is the number of
+** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
+** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
+** option to [sqlite3_db_config()] can be used to change the lookaside
+** configuration on individual connections.)^ </dd>
+**
+** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
+** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
+** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
+** the interface to a custom page cache implementation.)^
+** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
+**
+** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
+** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
+** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
+** the current page cache implementation into that object.)^ </dd>
+**
+** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
+** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
+** global [error log].
+** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
+** function with a call signature of void(*)(void*,int,const char*),
+** and a pointer to void. ^If the function pointer is not NULL, it is
+** invoked by [sqlite3_log()] to process each logging event.  ^If the
+** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
+** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
+** passed through as the first parameter to the application-defined logger
+** function whenever that function is invoked.  ^The second parameter to
+** the logger function is a copy of the first parameter to the corresponding
+** [sqlite3_log()] call and is intended to be a [result code] or an
+** [extended result code].  ^The third parameter passed to the logger is
+** log message after formatting via [sqlite3_snprintf()].
+** The SQLite logging interface is not reentrant; the logger function
+** supplied by the application must not invoke any SQLite interface.
+** In a multi-threaded application, the application-defined logger
+** function must be threadsafe. </dd>
+**
+** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
+** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
+** If non-zero, then URI handling is globally enabled. If the parameter is zero,
+** then URI handling is globally disabled.)^ ^If URI handling is globally
+** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
+** [sqlite3_open16()] or
+** specified as part of [ATTACH] commands are interpreted as URIs, regardless
+** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
+** connection is opened. ^If it is globally disabled, filenames are
+** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
+** database connection is opened. ^(By default, URI handling is globally
+** disabled. The default value may be changed by compiling with the
+** [SQLITE_USE_URI] symbol defined.)^
+**
+** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
+** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
+** argument which is interpreted as a boolean in order to enable or disable
+** the use of covering indices for full table scans in the query optimizer.
+** ^The default setting is determined
+** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
+** if that compile-time option is omitted.
+** The ability to disable the use of covering indices for full table scans
+** is because some incorrectly coded legacy applications might malfunction
+** when the optimization is enabled.  Providing the ability to
+** disable the optimization allows the older, buggy application code to work
+** without change even with newer versions of SQLite.
+**
+** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
+** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
+** <dd> These options are obsolete and should not be used by new code.
+** They are retained for backwards compatibility but are now no-ops.
+** </dd>
+**
+** [[SQLITE_CONFIG_SQLLOG]]
+** <dt>SQLITE_CONFIG_SQLLOG
+** <dd>This option is only available if sqlite is compiled with the
+** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
+** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
+** The second should be of type (void*). The callback is invoked by the library
+** in three separate circumstances, identified by the value passed as the
+** fourth parameter. If the fourth parameter is 0, then the database connection
+** passed as the second argument has just been opened. The third argument
+** points to a buffer containing the name of the main database file. If the
+** fourth parameter is 1, then the SQL statement that the third parameter
+** points to has just been executed. Or, if the fourth parameter is 2, then
+** the connection being passed as the second parameter is being closed. The
+** third parameter is passed NULL In this case.  An example of using this
+** configuration option can be seen in the "test_sqllog.c" source file in
+** the canonical SQLite source tree.</dd>
+**
+** [[SQLITE_CONFIG_MMAP_SIZE]]
+** <dt>SQLITE_CONFIG_MMAP_SIZE
+** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
+** that are the default mmap size limit (the default setting for
+** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
+** ^The default setting can be overridden by each database connection using
+** either the [PRAGMA mmap_size] command, or by using the
+** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
+** will be silently truncated if necessary so that it does not exceed the
+** compile-time maximum mmap size set by the
+** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
+** ^If either argument to this option is negative, then that argument is
+** changed to its compile-time default.
+**
+** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
+** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
+** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
+** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
+** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
+** that specifies the maximum size of the created heap.
+**
+** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
+** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
+** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
+** is a pointer to an integer and writes into that integer the number of extra
+** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
+** The amount of extra space required can change depending on the compiler,
+** target platform, and SQLite version.
+**
+** [[SQLITE_CONFIG_PMASZ]]
+** <dt>SQLITE_CONFIG_PMASZ
+** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
+** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
+** sorter to that integer.  The default minimum PMA Size is set by the
+** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
+** to help with sort operations when multithreaded sorting
+** is enabled (using the [PRAGMA threads] command) and the amount of content
+** to be sorted exceeds the page size times the minimum of the
+** [PRAGMA cache_size] setting and this value.
+**
+** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
+** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
+** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
+** becomes the [statement journal] spill-to-disk threshold.
+** [Statement journals] are held in memory until their size (in bytes)
+** exceeds this threshold, at which point they are written to disk.
+** Or if the threshold is -1, statement journals are always held
+** exclusively in memory.
+** Since many statement journals never become large, setting the spill
+** threshold to a value such as 64KiB can greatly reduce the amount of
+** I/O required to support statement rollback.
+** The default value for this setting is controlled by the
+** [SQLITE_STMTJRNL_SPILL] compile-time option.
+**
+** [[SQLITE_CONFIG_SORTERREF_SIZE]]
+** <dt>SQLITE_CONFIG_SORTERREF_SIZE
+** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
+** of type (int) - the new value of the sorter-reference size threshold.
+** Usually, when SQLite uses an external sort to order records according
+** to an ORDER BY clause, all fields required by the caller are present in the
+** sorted records. However, if SQLite determines based on the declared type
+** of a table column that its values are likely to be very large - larger
+** than the configured sorter-reference size threshold - then a reference
+** is stored in each sorted record and the required column values loaded
+** from the database as records are returned in sorted order. The default
+** value for this option is to never use this optimization. Specifying a
+** negative value for this option restores the default behavior.
+** This option is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
+**
+** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
+** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
+** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
+** [sqlite3_int64] parameter which is the default maximum size for an in-memory
+** database created using [sqlite3_deserialize()].  This default maximum
+** size can be adjusted up or down for individual databases using the
+** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
+** configuration setting is never used, then the default maximum is determined
+** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
+** compile-time option is not set, then the default maximum is 1073741824.
+**
+** [[SQLITE_CONFIG_ROWID_IN_VIEW]]
+** <dt>SQLITE_CONFIG_ROWID_IN_VIEW
+** <dd>The SQLITE_CONFIG_ROWID_IN_VIEW option enables or disables the ability
+** for VIEWs to have a ROWID.  The capability can only be enabled if SQLite is
+** compiled with -DSQLITE_ALLOW_ROWID_IN_VIEW, in which case the capability
+** defaults to on.  This configuration option queries the current setting or
+** changes the setting to off or on.  The argument is a pointer to an integer.
+** If that integer initially holds a value of 1, then the ability for VIEWs to
+** have ROWIDs is activated.  If the integer initially holds zero, then the
+** ability is deactivated.  Any other initial value for the integer leaves the
+** setting unchanged.  After changes, if any, the integer is written with
+** a 1 or 0, if the ability for VIEWs to have ROWIDs is on or off.  If SQLite
+** is compiled without -DSQLITE_ALLOW_ROWID_IN_VIEW (which is the usual and
+** recommended case) then the integer is always filled with zero, regardless
+** if its initial value.
+** </dl>
+*/
+#define SQLITE_CONFIG_SINGLETHREAD         1  /* nil */
+#define SQLITE_CONFIG_MULTITHREAD          2  /* nil */
+#define SQLITE_CONFIG_SERIALIZED           3  /* nil */
+#define SQLITE_CONFIG_MALLOC               4  /* sqlite3_mem_methods* */
+#define SQLITE_CONFIG_GETMALLOC            5  /* sqlite3_mem_methods* */
+#define SQLITE_CONFIG_SCRATCH              6  /* No longer used */
+#define SQLITE_CONFIG_PAGECACHE            7  /* void*, int sz, int N */
+#define SQLITE_CONFIG_HEAP                 8  /* void*, int nByte, int min */
+#define SQLITE_CONFIG_MEMSTATUS            9  /* boolean */
+#define SQLITE_CONFIG_MUTEX               10  /* sqlite3_mutex_methods* */
+#define SQLITE_CONFIG_GETMUTEX            11  /* sqlite3_mutex_methods* */
+/* previously SQLITE_CONFIG_CHUNKALLOC    12 which is now unused. */
+#define SQLITE_CONFIG_LOOKASIDE           13  /* int int */
+#define SQLITE_CONFIG_PCACHE              14  /* no-op */
+#define SQLITE_CONFIG_GETPCACHE           15  /* no-op */
+#define SQLITE_CONFIG_LOG                 16  /* xFunc, void* */
+#define SQLITE_CONFIG_URI                 17  /* int */
+#define SQLITE_CONFIG_PCACHE2             18  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_GETPCACHE2          19  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
+#define SQLITE_CONFIG_SQLLOG              21  /* xSqllog, void* */
+#define SQLITE_CONFIG_MMAP_SIZE           22  /* sqlite3_int64, sqlite3_int64 */
+#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
+#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
+#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
+#define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
+#define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
+#define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
+#define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
+#define SQLITE_CONFIG_ROWID_IN_VIEW       30  /* int* */
+
+/*
+** CAPI3REF: Database Connection Configuration Options
+**
+** These constants are the available integer configuration options that
+** can be passed as the second parameter to the [sqlite3_db_config()] interface.
+**
+** The [sqlite3_db_config()] interface is a var-args functions.  It takes a
+** variable number of parameters, though always at least two.  The number of
+** parameters passed into sqlite3_db_config() depends on which of these
+** constants is given as the second parameter.  This documentation page
+** refers to parameters beyond the second as "arguments".  Thus, when this
+** page says "the N-th argument" it means "the N-th parameter past the
+** configuration option" or "the (N+2)-th parameter to sqlite3_db_config()".
+**
+** New configuration options may be added in future releases of SQLite.
+** Existing configuration options might be discontinued.  Applications
+** should check the return code from [sqlite3_db_config()] to make sure that
+** the call worked.  ^The [sqlite3_db_config()] interface will return a
+** non-zero [error code] if a discontinued or unsupported configuration option
+** is invoked.
+**
+** <dl>
+** [[SQLITE_DBCONFIG_LOOKASIDE]]
+** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
+** <dd> The SQLITE_DBCONFIG_LOOKASIDE option is used to adjust the
+** configuration of the lookaside memory allocator within a database
+** connection.
+** The arguments to the SQLITE_DBCONFIG_LOOKASIDE option are <i>not</i>
+** in the [DBCONFIG arguments|usual format].
+** The SQLITE_DBCONFIG_LOOKASIDE option takes three arguments, not two,
+** so that a call to [sqlite3_db_config()] that uses SQLITE_DBCONFIG_LOOKASIDE
+** should have a total of five parameters.
+** ^The first argument (the third parameter to [sqlite3_db_config()] is a
+** pointer to a memory buffer to use for lookaside memory.
+** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
+** may be NULL in which case SQLite will allocate the
+** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
+** size of each lookaside buffer slot.  ^The third argument is the number of
+** slots.  The size of the buffer in the first argument must be greater than
+** or equal to the product of the second and third arguments.  The buffer
+** must be aligned to an 8-byte boundary.  ^If the second argument to
+** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
+** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
+** configuration for a database connection can only be changed when that
+** connection is not currently using lookaside memory, or in other words
+** when the "current value" returned by
+** [sqlite3_db_status](D,[SQLITE_DBSTATUS_LOOKASIDE_USED],...) is zero.
+** Any attempt to change the lookaside memory configuration when lookaside
+** memory is in use leaves the configuration unchanged and returns
+** [SQLITE_BUSY].)^</dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
+** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
+** <dd> ^This option is used to enable or disable the enforcement of
+** [foreign key constraints].  This is the same setting that is
+** enabled or disabled by the [PRAGMA foreign_keys] statement.
+** The first argument is an integer which is 0 to disable FK enforcement,
+** positive to enable FK enforcement or negative to leave FK enforcement
+** unchanged.  The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether FK enforcement is off or on
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the FK enforcement setting is not reported back. </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
+** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
+** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
+** There should be two additional arguments.
+** The first argument is an integer which is 0 to disable triggers,
+** positive to enable triggers or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether triggers are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the trigger setting is not reported back.
+**
+** <p>Originally this option disabled all triggers.  ^(However, since
+** SQLite version 3.35.0, TEMP triggers are still allowed even if
+** this option is off.  So, in other words, this option now only disables
+** triggers in the main database schema or in the schemas of [ATTACH]-ed
+** databases.)^ </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
+** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
+** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
+** There must be two additional arguments.
+** The first argument is an integer which is 0 to disable views,
+** positive to enable views or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether views are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the view setting is not reported back.
+**
+** <p>Originally this option disabled all views.  ^(However, since
+** SQLite version 3.35.0, TEMP views are still allowed even if
+** this option is off.  So, in other words, this option now only disables
+** views in the main database schema or in the schemas of ATTACH-ed
+** databases.)^ </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
+** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
+** <dd> ^This option is used to enable or disable the
+** [fts3_tokenizer()] function which is part of the
+** [FTS3] full-text search engine extension.
+** There must be two additional arguments.
+** The first argument is an integer which is 0 to disable fts3_tokenizer() or
+** positive to enable fts3_tokenizer() or negative to leave the setting
+** unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the new setting is not reported back. </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
+** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
+** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
+** interface independently of the [load_extension()] SQL function.
+** The [sqlite3_enable_load_extension()] API enables or disables both the
+** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
+** There must be two additional arguments.
+** When the first argument to this interface is 1, then only the C-API is
+** enabled and the SQL function remains disabled.  If the first argument to
+** this interface is 0, then both the C-API and the SQL function are disabled.
+** If the first argument is -1, then no changes are made to state of either the
+** C-API or the SQL function.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
+** is disabled or enabled following this call.  The second parameter may
+** be a NULL pointer, in which case the new setting is not reported back.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
+** <dd> ^This option is used to change the name of the "main" database
+** schema.  This option does not follow the
+** [DBCONFIG arguments|usual SQLITE_DBCONFIG argument format].
+** This option takes exactly one additional argument so that the
+** [sqlite3_db_config()] call has a total of three parameters.  The
+** extra argument must be a pointer to a constant UTF8 string which
+** will become the new schema name in place of "main".  ^SQLite does
+** not make a copy of the new main schema name string, so the application
+** must ensure that the argument passed into SQLITE_DBCONFIG MAINDBNAME
+** is unchanged until after the database connection closes.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
+** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
+** <dd> Usually, when a database in [WAL mode] is closed or detached from a
+** database handle, SQLite checks if if there are other connections to the
+** same database, and if there are no other database connection (if the
+** connection being closed is the last open connection to the database),
+** then SQLite performs a [checkpoint] before closing the connection and
+** deletes the WAL file.  The SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE option can
+** be used to override that behavior. The first argument passed to this
+** operation (the third parameter to [sqlite3_db_config()]) is an integer
+** which is positive to disable checkpoints-on-close, or zero (the default)
+** to enable them, and negative to leave the setting unchanged.
+** The second argument (the fourth parameter) is a pointer to an integer
+** into which is written 0 or 1 to indicate whether checkpoints-on-close
+** have been disabled - 0 if they are not disabled, 1 if they are.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
+** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
+** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
+** a single SQL query statement will always use the same algorithm regardless
+** of values of [bound parameters].)^ The QPSG disables some query optimizations
+** that look at the values of bound parameters, which can make some queries
+** slower.  But the QPSG has the advantage of more predictable behavior.  With
+** the QPSG active, SQLite will always use the same query plan in the field as
+** was used during testing in the lab.
+** The first argument to this setting is an integer which is 0 to disable
+** the QPSG, positive to enable QPSG, or negative to leave the setting
+** unchanged. The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
+** following this call.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
+** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
+** include output for any operations performed by trigger programs. This
+** option is used to set or clear (the default) a flag that governs this
+** behavior. The first parameter passed to this operation is an integer -
+** positive to enable output for trigger programs, or zero to disable it,
+** or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which is written
+** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
+** it is not disabled, 1 if it is.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
+** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
+** [VACUUM] in order to reset a database back to an empty database
+** with no schema and no content. The following process works even for
+** a badly corrupted database file:
+** <ol>
+** <li> If the database connection is newly opened, make sure it has read the
+**      database schema by preparing then discarding some query against the
+**      database, or calling sqlite3_table_column_metadata(), ignoring any
+**      errors.  This step is only necessary if the application desires to keep
+**      the database in WAL mode after the reset if it was in WAL mode before
+**      the reset.
+** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
+** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
+** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
+** </ol>
+** Because resetting a database is destructive and irreversible, the
+** process requires the use of this obscure API and multiple steps to
+** help ensure that it does not happen by accident. Because this
+** feature must be capable of resetting corrupt databases, and
+** shutting down virtual tables may require access to that corrupt
+** storage, the library must abandon any installed virtual tables
+** without calling their xDestroy() methods.
+**
+** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
+** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
+** "defensive" flag for a database connection.  When the defensive
+** flag is enabled, language features that allow ordinary SQL to
+** deliberately corrupt the database file are disabled.  The disabled
+** features include but are not limited to the following:
+** <ul>
+** <li> The [PRAGMA writable_schema=ON] statement.
+** <li> The [PRAGMA journal_mode=OFF] statement.
+** <li> The [PRAGMA schema_version=N] statement.
+** <li> Writes to the [sqlite_dbpage] virtual table.
+** <li> Direct writes to [shadow tables].
+** </ul>
+** </dd>
+**
+** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
+** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
+** "writable_schema" flag. This has the same effect and is logically equivalent
+** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
+** The first argument to this setting is an integer which is 0 to disable
+** the writable_schema, positive to enable writable_schema, or negative to
+** leave the setting unchanged. The second parameter is a pointer to an
+** integer into which is written 0 or 1 to indicate whether the writable_schema
+** is enabled or disabled following this call.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
+** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
+** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
+** the legacy behavior of the [ALTER TABLE RENAME] command such it
+** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
+** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
+** additional information. This feature can also be turned on and off
+** using the [PRAGMA legacy_alter_table] statement.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_DQS_DML]]
+** <dt>SQLITE_DBCONFIG_DQS_DML</dt>
+** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
+** the legacy [double-quoted string literal] misfeature for DML statements
+** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
+** default value of this setting is determined by the [-DSQLITE_DQS]
+** compile-time option.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_DQS_DDL]]
+** <dt>SQLITE_DBCONFIG_DQS_DDL</dt>
+** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
+** the legacy [double-quoted string literal] misfeature for DDL statements,
+** such as CREATE TABLE and CREATE INDEX. The
+** default value of this setting is determined by the [-DSQLITE_DQS]
+** compile-time option.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
+** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</dt>
+** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
+** assume that database schemas are untainted by malicious content.
+** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
+** takes additional defensive steps to protect the application from harm
+** including:
+** <ul>
+** <li> Prohibit the use of SQL functions inside triggers, views,
+** CHECK constraints, DEFAULT clauses, expression indexes,
+** partial indexes, or generated columns
+** unless those functions are tagged with [SQLITE_INNOCUOUS].
+** <li> Prohibit the use of virtual tables inside of triggers or views
+** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
+** </ul>
+** This setting defaults to "on" for legacy compatibility, however
+** all applications are advised to turn it off if possible. This setting
+** can also be controlled using the [PRAGMA trusted_schema] statement.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
+** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</dt>
+** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
+** the legacy file format flag.  When activated, this flag causes all newly
+** created database file to have a schema format version number (the 4-byte
+** integer found at offset 44 into the database header) of 1.  This in turn
+** means that the resulting database file will be readable and writable by
+** any SQLite version back to 3.0.0 ([dateof:3.0.0]).  Without this setting,
+** newly created databases are generally not understandable by SQLite versions
+** prior to 3.3.0 ([dateof:3.3.0]).  As these words are written, there
+** is now scarcely any need to generate database files that are compatible
+** all the way back to version 3.0.0, and so this setting is of little
+** practical use, but is provided so that SQLite can continue to claim the
+** ability to generate new database files that are compatible with  version
+** 3.0.0.
+** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
+** the [VACUUM] command will fail with an obscure error when attempting to
+** process a table with generated columns and a descending index.  This is
+** not considered a bug since SQLite versions 3.3.0 and earlier do not support
+** either generated columns or descending indexes.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_STMT_SCANSTATUS]]
+** <dt>SQLITE_DBCONFIG_STMT_SCANSTATUS</dt>
+** <dd>The SQLITE_DBCONFIG_STMT_SCANSTATUS option is only useful in
+** SQLITE_ENABLE_STMT_SCANSTATUS builds. In this case, it sets or clears
+** a flag that enables collection of the sqlite3_stmt_scanstatus_v2()
+** statistics. For statistics to be collected, the flag must be set on
+** the database handle both when the SQL statement is prepared and when it
+** is stepped. The flag is set (collection of statistics is enabled)
+** by default. <p>This option takes two arguments: an integer and a pointer to
+** an integer..  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the statement scanstatus option.  If the second argument
+** is not NULL, then the value of the statement scanstatus setting after
+** processing the first argument is written into the integer that the second
+** argument points to.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_REVERSE_SCANORDER]]
+** <dt>SQLITE_DBCONFIG_REVERSE_SCANORDER</dt>
+** <dd>The SQLITE_DBCONFIG_REVERSE_SCANORDER option changes the default order
+** in which tables and indexes are scanned so that the scans start at the end
+** and work toward the beginning rather than starting at the beginning and
+** working toward the end. Setting SQLITE_DBCONFIG_REVERSE_SCANORDER is the
+** same as setting [PRAGMA reverse_unordered_selects]. <p>This option takes
+** two arguments which are an integer and a pointer to an integer.  The first
+** argument is 1, 0, or -1 to enable, disable, or leave unchanged the
+** reverse scan order flag, respectively.  If the second argument is not NULL,
+** then 0 or 1 is written into the integer that the second argument points to
+** depending on if the reverse scan order flag is set after processing the
+** first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]]
+** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE option enables or disables
+** the ability of the [ATTACH DATABASE] SQL command to create a new database
+** file if the database filed named in the ATTACH command does not already
+** exist.  This ability of ATTACH to create a new database is enabled by
+** default.  Applications can disable or reenable the ability for ATTACH to
+** create new database files using this DBCONFIG option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the attach-create flag, respectively.  If the second
+** argument is not NULL, then 0 or 1 is written into the integer that the
+** second argument points to depending on if the attach-create flag is set
+** after processing the first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE]]
+** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE option enables or disables the
+** ability of the [ATTACH DATABASE] SQL command to open a database for writing.
+** This capability is enabled by default.  Applications can disable or
+** reenable this capability using the current DBCONFIG option.  If the
+** the this capability is disabled, the [ATTACH] command will still work,
+** but the database will be opened read-only.  If this option is disabled,
+** then the ability to create a new database using [ATTACH] is also disabled,
+** regardless of the value of the [SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]
+** option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the ability to ATTACH another database for writing,
+** respectively.  If the second argument is not NULL, then 0 or 1 is written
+** into the integer to which the second argument points, depending on whether
+** the ability to ATTACH a read/write database is enabled or disabled
+** after processing the first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_COMMENTS]]
+** <dt>SQLITE_DBCONFIG_ENABLE_COMMENTS</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_COMMENTS option enables or disables the
+** ability to include comments in SQL text.  Comments are enabled by default.
+** An application can disable or reenable comments in SQL text using this
+** DBCONFIG option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the ability to use comments in SQL text,
+** respectively.  If the second argument is not NULL, then 0 or 1 is written
+** into the integer that the second argument points to depending on if
+** comments are allowed in SQL text after processing the first argument.
+** </dd>
+**
+** </dl>
+**
+** [[DBCONFIG arguments]] <h3>Arguments To SQLITE_DBCONFIG Options</h3>
+**
+** <p>Most of the SQLITE_DBCONFIG options take two arguments, so that the
+** overall call to [sqlite3_db_config()] has a total of four parameters.
+** The first argument (the third parameter to sqlite3_db_config()) is a integer.
+** The second argument is a pointer to an integer.  If the first argument is 1,
+** then the option becomes enabled.  If the first integer argument is 0, then the
+** option is disabled.  If the first argument is -1, then the option setting
+** is unchanged.  The second argument, the pointer to an integer, may be NULL.
+** If the second argument is not NULL, then a value of 0 or 1 is written into
+** the integer to which the second argument points, depending on whether the
+** setting is disabled or enabled after applying any changes specified by
+** the first argument.
+**
+** <p>While most SQLITE_DBCONFIG options use the argument format
+** described in the previous paragraph, the [SQLITE_DBCONFIG_MAINDBNAME]
+** and [SQLITE_DBCONFIG_LOOKASIDE] options are different.  See the
+** documentation of those exceptional options for details.
+*/
+#define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
+#define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
+#define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
+#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
+#define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
+#define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
+#define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
+#define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
+#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
+#define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
+#define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
+#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
+#define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
+#define SQLITE_DBCONFIG_STMT_SCANSTATUS       1018 /* int int* */
+#define SQLITE_DBCONFIG_REVERSE_SCANORDER     1019 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE  1020 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE   1021 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_COMMENTS       1022 /* int int* */
+#define SQLITE_DBCONFIG_MAX                   1022 /* Largest DBCONFIG */
+
+/*
+** CAPI3REF: Enable Or Disable Extended Result Codes
+** METHOD: sqlite3
+**
+** ^The sqlite3_extended_result_codes() routine enables or disables the
+** [extended result codes] feature of SQLite. ^The extended result
+** codes are disabled by default for historical compatibility.
+*/
+SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
+
+/*
+** CAPI3REF: Last Insert Rowid
+** METHOD: sqlite3
+**
+** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
+** has a unique 64-bit signed
+** integer key called the [ROWID | "rowid"]. ^The rowid is always available
+** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
+** names are not also used by explicitly declared columns. ^If
+** the table has a column of type [INTEGER PRIMARY KEY] then that column
+** is another alias for the rowid.
+**
+** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
+** the most recent successful [INSERT] into a rowid table or [virtual table]
+** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
+** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
+** on the database connection D, then sqlite3_last_insert_rowid(D) returns
+** zero.
+**
+** As well as being set automatically as rows are inserted into database
+** tables, the value returned by this function may be set explicitly by
+** [sqlite3_set_last_insert_rowid()]
+**
+** Some virtual table implementations may INSERT rows into rowid tables as
+** part of committing a transaction (e.g. to flush data accumulated in memory
+** to disk). In this case subsequent calls to this function return the rowid
+** associated with these internal INSERT operations, which leads to
+** unintuitive results. Virtual table implementations that do write to rowid
+** tables in this way can avoid this problem by restoring the original
+** rowid value using [sqlite3_set_last_insert_rowid()] before returning
+** control to the user.
+**
+** ^(If an [INSERT] occurs within a trigger then this routine will
+** return the [rowid] of the inserted row as long as the trigger is
+** running. Once the trigger program ends, the value returned
+** by this routine reverts to what it was before the trigger was fired.)^
+**
+** ^An [INSERT] that fails due to a constraint violation is not a
+** successful [INSERT] and does not change the value returned by this
+** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
+** and INSERT OR ABORT make no changes to the return value of this
+** routine when their insertion fails.  ^(When INSERT OR REPLACE
+** encounters a constraint violation, it does not fail.  The
+** INSERT continues to completion after deleting rows that caused
+** the constraint problem so INSERT OR REPLACE will always change
+** the return value of this interface.)^
+**
+** ^For the purposes of this routine, an [INSERT] is considered to
+** be successful even if it is subsequently rolled back.
+**
+** This function is accessible to SQL statements via the
+** [last_insert_rowid() SQL function].
+**
+** If a separate thread performs a new [INSERT] on the same
+** database connection while the [sqlite3_last_insert_rowid()]
+** function is running and thus changes the last insert [rowid],
+** then the value returned by [sqlite3_last_insert_rowid()] is
+** unpredictable and might not equal either the old or the new
+** last insert [rowid].
+*/
+SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
+
+/*
+** CAPI3REF: Set the Last Insert Rowid value.
+** METHOD: sqlite3
+**
+** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
+** set the value returned by calling sqlite3_last_insert_rowid(D) to R
+** without inserting a row into the database.
+*/
+SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
+
+/*
+** CAPI3REF: Count The Number Of Rows Modified
+** METHOD: sqlite3
+**
+** ^These functions return the number of rows modified, inserted or
+** deleted by the most recently completed INSERT, UPDATE or DELETE
+** statement on the database connection specified by the only parameter.
+** The two functions are identical except for the type of the return value
+** and that if the number of rows modified by the most recent INSERT, UPDATE,
+** or DELETE is greater than the maximum value supported by type "int", then
+** the return value of sqlite3_changes() is undefined. ^Executing any other
+** type of SQL statement does not modify the value returned by these functions.
+** For the purposes of this interface, a CREATE TABLE AS SELECT statement
+** does not count as an INSERT, UPDATE or DELETE statement and hence the rows
+** added to the new table by the CREATE TABLE AS SELECT statement are not
+** counted.
+**
+** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
+** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
+** [foreign key actions] or [REPLACE] constraint resolution are not counted.
+**
+** Changes to a view that are intercepted by
+** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
+** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
+** DELETE statement run on a view is always zero. Only changes made to real
+** tables are counted.
+**
+** Things are more complicated if the sqlite3_changes() function is
+** executed while a trigger program is running. This may happen if the
+** program uses the [changes() SQL function], or if some other callback
+** function invokes sqlite3_changes() directly. Essentially:
+**
+** <ul>
+**   <li> ^(Before entering a trigger program the value returned by
+**        sqlite3_changes() function is saved. After the trigger program
+**        has finished, the original value is restored.)^
+**
+**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
+**        statement sets the value returned by sqlite3_changes()
+**        upon completion as normal. Of course, this value will not include
+**        any changes performed by sub-triggers, as the sqlite3_changes()
+**        value will be saved and restored after each sub-trigger has run.)^
+** </ul>
+**
+** ^This means that if the changes() SQL function (or similar) is used
+** by the first INSERT, UPDATE or DELETE statement within a trigger, it
+** returns the value as set when the calling statement began executing.
+** ^If it is used by the second or subsequent such statement within a trigger
+** program, the value returned reflects the number of rows modified by the
+** previous INSERT, UPDATE or DELETE statement within the same trigger.
+**
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_changes()] is running then the value returned
+** is unpredictable and not meaningful.
+**
+** See also:
+** <ul>
+** <li> the [sqlite3_total_changes()] interface
+** <li> the [count_changes pragma]
+** <li> the [changes() SQL function]
+** <li> the [data_version pragma]
+** </ul>
+*/
+SQLITE_API int sqlite3_changes(sqlite3*);
+SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3*);
+
+/*
+** CAPI3REF: Total Number Of Rows Modified
+** METHOD: sqlite3
+**
+** ^These functions return the total number of rows inserted, modified or
+** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
+** since the database connection was opened, including those executed as
+** part of trigger programs. The two functions are identical except for the
+** type of the return value and that if the number of rows modified by the
+** connection exceeds the maximum value supported by type "int", then
+** the return value of sqlite3_total_changes() is undefined. ^Executing
+** any other type of SQL statement does not affect the value returned by
+** sqlite3_total_changes().
+**
+** ^Changes made as part of [foreign key actions] are included in the
+** count, but those made as part of REPLACE constraint resolution are
+** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
+** are not counted.
+**
+** The [sqlite3_total_changes(D)] interface only reports the number
+** of rows that changed due to SQL statement run against database
+** connection D.  Any changes by other database connections are ignored.
+** To detect changes against a database file from other database
+** connections use the [PRAGMA data_version] command or the
+** [SQLITE_FCNTL_DATA_VERSION] [file control].
+**
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_total_changes()] is running then the value
+** returned is unpredictable and not meaningful.
+**
+** See also:
+** <ul>
+** <li> the [sqlite3_changes()] interface
+** <li> the [count_changes pragma]
+** <li> the [changes() SQL function]
+** <li> the [data_version pragma]
+** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
+** </ul>
+*/
+SQLITE_API int sqlite3_total_changes(sqlite3*);
+SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3*);
+
+/*
+** CAPI3REF: Interrupt A Long-Running Query
+** METHOD: sqlite3
+**
+** ^This function causes any pending database operation to abort and
+** return at its earliest opportunity. This routine is typically
+** called in response to a user action such as pressing "Cancel"
+** or Ctrl-C where the user wants a long query operation to halt
+** immediately.
+**
+** ^It is safe to call this routine from a thread different from the
+** thread that is currently running the database operation.  But it
+** is not safe to call this routine with a [database connection] that
+** is closed or might close before sqlite3_interrupt() returns.
+**
+** ^If an SQL operation is very nearly finished at the time when
+** sqlite3_interrupt() is called, then it might not have an opportunity
+** to be interrupted and might continue to completion.
+**
+** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
+** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
+** that is inside an explicit transaction, then the entire transaction
+** will be rolled back automatically.
+**
+** ^The sqlite3_interrupt(D) call is in effect until all currently running
+** SQL statements on [database connection] D complete.  ^Any new SQL statements
+** that are started after the sqlite3_interrupt() call and before the
+** running statement count reaches zero are interrupted as if they had been
+** running prior to the sqlite3_interrupt() call.  ^New SQL statements
+** that are started after the running statement count reaches zero are
+** not effected by the sqlite3_interrupt().
+** ^A call to sqlite3_interrupt(D) that occurs when there are no running
+** SQL statements is a no-op and has no effect on SQL statements
+** that are started after the sqlite3_interrupt() call returns.
+**
+** ^The [sqlite3_is_interrupted(D)] interface can be used to determine whether
+** or not an interrupt is currently in effect for [database connection] D.
+** It returns 1 if an interrupt is currently in effect, or 0 otherwise.
+*/
+SQLITE_API void sqlite3_interrupt(sqlite3*);
+SQLITE_API int sqlite3_is_interrupted(sqlite3*);
+
+/*
+** CAPI3REF: Determine If An SQL Statement Is Complete
+**
+** These routines are useful during command-line input to determine if the
+** currently entered text seems to form a complete SQL statement or
+** if additional input is needed before sending the text into
+** SQLite for parsing.  ^These routines return 1 if the input string
+** appears to be a complete SQL statement.  ^A statement is judged to be
+** complete if it ends with a semicolon token and is not a prefix of a
+** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
+** string literals or quoted identifier names or comments are not
+** independent tokens (they are part of the token in which they are
+** embedded) and thus do not count as a statement terminator.  ^Whitespace
+** and comments that follow the final semicolon are ignored.
+**
+** ^These routines return 0 if the statement is incomplete.  ^If a
+** memory allocation fails, then SQLITE_NOMEM is returned.
+**
+** ^These routines do not parse the SQL statements thus
+** will not detect syntactically incorrect SQL.
+**
+** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
+** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
+** automatically by sqlite3_complete16().  If that initialization fails,
+** then the return value from sqlite3_complete16() will be non-zero
+** regardless of whether or not the input SQL is complete.)^
+**
+** The input to [sqlite3_complete()] must be a zero-terminated
+** UTF-8 string.
+**
+** The input to [sqlite3_complete16()] must be a zero-terminated
+** UTF-16 string in native byte order.
+*/
+SQLITE_API int sqlite3_complete(const char *sql);
+SQLITE_API int sqlite3_complete16(const void *sql);
+
+/*
+** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
+** KEYWORDS: {busy-handler callback} {busy handler}
+** METHOD: sqlite3
+**
+** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
+** that might be invoked with argument P whenever
+** an attempt is made to access a database table associated with
+** [database connection] D when another thread
+** or process has the table locked.
+** The sqlite3_busy_handler() interface is used to implement
+** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
+**
+** ^If the busy callback is NULL, then [SQLITE_BUSY]
+** is returned immediately upon encountering the lock.  ^If the busy callback
+** is not NULL, then the callback might be invoked with two arguments.
+**
+** ^The first argument to the busy handler is a copy of the void* pointer which
+** is the third argument to sqlite3_busy_handler().  ^The second argument to
+** the busy handler callback is the number of times that the busy handler has
+** been invoked previously for the same locking event.  ^If the
+** busy callback returns 0, then no additional attempts are made to
+** access the database and [SQLITE_BUSY] is returned
+** to the application.
+** ^If the callback returns non-zero, then another attempt
+** is made to access the database and the cycle repeats.
+**
+** The presence of a busy handler does not guarantee that it will be invoked
+** when there is lock contention. ^If SQLite determines that invoking the busy
+** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
+** to the application instead of invoking the
+** busy handler.
+** Consider a scenario where one process is holding a read lock that
+** it is trying to promote to a reserved lock and
+** a second process is holding a reserved lock that it is trying
+** to promote to an exclusive lock.  The first process cannot proceed
+** because it is blocked by the second and the second process cannot
+** proceed because it is blocked by the first.  If both processes
+** invoke the busy handlers, neither will make any progress.  Therefore,
+** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
+** will induce the first process to release its read lock and allow
+** the second process to proceed.
+**
+** ^The default busy callback is NULL.
+**
+** ^(There can only be a single busy handler defined for each
+** [database connection].  Setting a new busy handler clears any
+** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
+** or evaluating [PRAGMA busy_timeout=N] will change the
+** busy handler and thus clear any previously set busy handler.
+**
+** The busy callback should not take any actions which modify the
+** database connection that invoked the busy handler.  In other words,
+** the busy handler is not reentrant.  Any such actions
+** result in undefined behavior.
+**
+** A busy handler must not close the database connection
+** or [prepared statement] that invoked the busy handler.
+*/
+SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
+
+/*
+** CAPI3REF: Set A Busy Timeout
+** METHOD: sqlite3
+**
+** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
+** for a specified amount of time when a table is locked.  ^The handler
+** will sleep multiple times until at least "ms" milliseconds of sleeping
+** have accumulated.  ^After at least "ms" milliseconds of sleeping,
+** the handler returns 0 which causes [sqlite3_step()] to return
+** [SQLITE_BUSY].
+**
+** ^Calling this routine with an argument less than or equal to zero
+** turns off all busy handlers.
+**
+** ^(There can only be a single busy handler for a particular
+** [database connection] at any given moment.  If another busy handler
+** was defined  (using [sqlite3_busy_handler()]) prior to calling
+** this routine, that other busy handler is cleared.)^
+**
+** See also:  [PRAGMA busy_timeout]
+*/
+SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
+
+/*
+** CAPI3REF: Convenience Routines For Running Queries
+** METHOD: sqlite3
+**
+** This is a legacy interface that is preserved for backwards compatibility.
+** Use of this interface is not recommended.
+**
+** Definition: A <b>result table</b> is memory data structure created by the
+** [sqlite3_get_table()] interface.  A result table records the
+** complete query results from one or more queries.
+**
+** The table conceptually has a number of rows and columns.  But
+** these numbers are not part of the result table itself.  These
+** numbers are obtained separately.  Let N be the number of rows
+** and M be the number of columns.
+**
+** A result table is an array of pointers to zero-terminated UTF-8 strings.
+** There are (N+1)*M elements in the array.  The first M pointers point
+** to zero-terminated strings that  contain the names of the columns.
+** The remaining entries all point to query results.  NULL values result
+** in NULL pointers.  All other values are in their UTF-8 zero-terminated
+** string representation as returned by [sqlite3_column_text()].
+**
+** A result table might consist of one or more memory allocations.
+** It is not safe to pass a result table directly to [sqlite3_free()].
+** A result table should be deallocated using [sqlite3_free_table()].
+**
+** ^(As an example of the result table format, suppose a query result
+** is as follows:
+**
+** <blockquote><pre>
+**        Name        | Age
+**        -----------------------
+**        Alice       | 43
+**        Bob         | 28
+**        Cindy       | 21
+** </pre></blockquote>
+**
+** There are two columns (M==2) and three rows (N==3).  Thus the
+** result table has 8 entries.  Suppose the result table is stored
+** in an array named azResult.  Then azResult holds this content:
+**
+** <blockquote><pre>
+**        azResult[0] = "Name";
+**        azResult[1] = "Age";
+**        azResult[2] = "Alice";
+**        azResult[3] = "43";
+**        azResult[4] = "Bob";
+**        azResult[5] = "28";
+**        azResult[6] = "Cindy";
+**        azResult[7] = "21";
+** </pre></blockquote>)^
+**
+** ^The sqlite3_get_table() function evaluates one or more
+** semicolon-separated SQL statements in the zero-terminated UTF-8
+** string of its 2nd parameter and returns a result table to the
+** pointer given in its 3rd parameter.
+**
+** After the application has finished with the result from sqlite3_get_table(),
+** it must pass the result table pointer to sqlite3_free_table() in order to
+** release the memory that was malloced.  Because of the way the
+** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
+** function must not try to call [sqlite3_free()] directly.  Only
+** [sqlite3_free_table()] is able to release the memory properly and safely.
+**
+** The sqlite3_get_table() interface is implemented as a wrapper around
+** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
+** to any internal data structures of SQLite.  It uses only the public
+** interface defined here.  As a consequence, errors that occur in the
+** wrapper layer outside of the internal [sqlite3_exec()] call are not
+** reflected in subsequent calls to [sqlite3_errcode()] or
+** [sqlite3_errmsg()].
+*/
+SQLITE_API int sqlite3_get_table(
+  sqlite3 *db,          /* An open database */
+  const char *zSql,     /* SQL to be evaluated */
+  char ***pazResult,    /* Results of the query */
+  int *pnRow,           /* Number of result rows written here */
+  int *pnColumn,        /* Number of result columns written here */
+  char **pzErrmsg       /* Error msg written here */
+);
+SQLITE_API void sqlite3_free_table(char **result);
+
+/*
+** CAPI3REF: Formatted String Printing Functions
+**
+** These routines are work-alikes of the "printf()" family of functions
+** from the standard C library.
+** These routines understand most of the common formatting options from
+** the standard library printf()
+** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
+** See the [built-in printf()] documentation for details.
+**
+** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
+** results into memory obtained from [sqlite3_malloc64()].
+** The strings returned by these two routines should be
+** released by [sqlite3_free()].  ^Both routines return a
+** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
+** memory to hold the resulting string.
+**
+** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
+** the standard C library.  The result is written into the
+** buffer supplied as the second parameter whose size is given by
+** the first parameter. Note that the order of the
+** first two parameters is reversed from snprintf().)^  This is an
+** historical accident that cannot be fixed without breaking
+** backwards compatibility.  ^(Note also that sqlite3_snprintf()
+** returns a pointer to its buffer instead of the number of
+** characters actually written into the buffer.)^  We admit that
+** the number of characters written would be a more useful return
+** value but we cannot change the implementation of sqlite3_snprintf()
+** now without breaking compatibility.
+**
+** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
+** guarantees that the buffer is always zero-terminated.  ^The first
+** parameter "n" is the total size of the buffer, including space for
+** the zero terminator.  So the longest string that can be completely
+** written will be n-1 characters.
+**
+** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
+**
+** See also:  [built-in printf()], [printf() SQL function]
+*/
+SQLITE_API char *sqlite3_mprintf(const char*,...);
+SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
+SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
+SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
+
+/*
+** CAPI3REF: Memory Allocation Subsystem
+**
+** The SQLite core uses these three routines for all of its own
+** internal memory allocation needs. "Core" in the previous sentence
+** does not include operating-system specific [VFS] implementation.  The
+** Windows VFS uses native malloc() and free() for some operations.
+**
+** ^The sqlite3_malloc() routine returns a pointer to a block
+** of memory at least N bytes in length, where N is the parameter.
+** ^If sqlite3_malloc() is unable to obtain sufficient free
+** memory, it returns a NULL pointer.  ^If the parameter N to
+** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
+** a NULL pointer.
+**
+** ^The sqlite3_malloc64(N) routine works just like
+** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
+** of a signed 32-bit integer.
+**
+** ^Calling sqlite3_free() with a pointer previously returned
+** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
+** that it might be reused.  ^The sqlite3_free() routine is
+** a no-op if is called with a NULL pointer.  Passing a NULL pointer
+** to sqlite3_free() is harmless.  After being freed, memory
+** should neither be read nor written.  Even reading previously freed
+** memory might result in a segmentation fault or other severe error.
+** Memory corruption, a segmentation fault, or other severe error
+** might result if sqlite3_free() is called with a non-NULL pointer that
+** was not obtained from sqlite3_malloc() or sqlite3_realloc().
+**
+** ^The sqlite3_realloc(X,N) interface attempts to resize a
+** prior memory allocation X to be at least N bytes.
+** ^If the X parameter to sqlite3_realloc(X,N)
+** is a NULL pointer then its behavior is identical to calling
+** sqlite3_malloc(N).
+** ^If the N parameter to sqlite3_realloc(X,N) is zero or
+** negative then the behavior is exactly the same as calling
+** sqlite3_free(X).
+** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
+** of at least N bytes in size or NULL if insufficient memory is available.
+** ^If M is the size of the prior allocation, then min(N,M) bytes
+** of the prior allocation are copied into the beginning of buffer returned
+** by sqlite3_realloc(X,N) and the prior allocation is freed.
+** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
+** prior allocation is not freed.
+**
+** ^The sqlite3_realloc64(X,N) interfaces works the same as
+** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
+** of a 32-bit signed integer.
+**
+** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
+** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
+** sqlite3_msize(X) returns the size of that memory allocation in bytes.
+** ^The value returned by sqlite3_msize(X) might be larger than the number
+** of bytes requested when X was allocated.  ^If X is a NULL pointer then
+** sqlite3_msize(X) returns zero.  If X points to something that is not
+** the beginning of memory allocation, or if it points to a formerly
+** valid memory allocation that has now been freed, then the behavior
+** of sqlite3_msize(X) is undefined and possibly harmful.
+**
+** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
+** sqlite3_malloc64(), and sqlite3_realloc64()
+** is always aligned to at least an 8 byte boundary, or to a
+** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
+** option is used.
+**
+** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
+** must be either NULL or else pointers obtained from a prior
+** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
+** not yet been released.
+**
+** The application must not read or write any part of
+** a block of memory after it has been released using
+** [sqlite3_free()] or [sqlite3_realloc()].
+*/
+SQLITE_API void *sqlite3_malloc(int);
+SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
+SQLITE_API void *sqlite3_realloc(void*, int);
+SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
+SQLITE_API void sqlite3_free(void*);
+SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
+
+/*
+** CAPI3REF: Memory Allocator Statistics
+**
+** SQLite provides these two interfaces for reporting on the status
+** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
+** routines, which form the built-in memory allocation subsystem.
+**
+** ^The [sqlite3_memory_used()] routine returns the number of bytes
+** of memory currently outstanding (malloced but not freed).
+** ^The [sqlite3_memory_highwater()] routine returns the maximum
+** value of [sqlite3_memory_used()] since the high-water mark
+** was last reset.  ^The values returned by [sqlite3_memory_used()] and
+** [sqlite3_memory_highwater()] include any overhead
+** added by SQLite in its implementation of [sqlite3_malloc()],
+** but not overhead added by the any underlying system library
+** routines that [sqlite3_malloc()] may call.
+**
+** ^The memory high-water mark is reset to the current value of
+** [sqlite3_memory_used()] if and only if the parameter to
+** [sqlite3_memory_highwater()] is true.  ^The value returned
+** by [sqlite3_memory_highwater(1)] is the high-water mark
+** prior to the reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
+
+/*
+** CAPI3REF: Pseudo-Random Number Generator
+**
+** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
+** select random [ROWID | ROWIDs] when inserting new records into a table that
+** already uses the largest possible [ROWID].  The PRNG is also used for
+** the built-in random() and randomblob() SQL functions.  This interface allows
+** applications to access the same PRNG for other purposes.
+**
+** ^A call to this routine stores N bytes of randomness into buffer P.
+** ^The P parameter can be a NULL pointer.
+**
+** ^If this routine has not been previously called or if the previous
+** call had N less than one or a NULL pointer for P, then the PRNG is
+** seeded using randomness obtained from the xRandomness method of
+** the default [sqlite3_vfs] object.
+** ^If the previous call to this routine had an N of 1 or more and a
+** non-NULL P then the pseudo-randomness is generated
+** internally and without recourse to the [sqlite3_vfs] xRandomness
+** method.
+*/
+SQLITE_API void sqlite3_randomness(int N, void *P);
+
+/*
+** CAPI3REF: Compile-Time Authorization Callbacks
+** METHOD: sqlite3
+** KEYWORDS: {authorizer callback}
+**
+** ^This routine registers an authorizer callback with a particular
+** [database connection], supplied in the first argument.
+** ^The authorizer callback is invoked as SQL statements are being compiled
+** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
+** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
+** and [sqlite3_prepare16_v3()].  ^At various
+** points during the compilation process, as logic is being created
+** to perform various actions, the authorizer callback is invoked to
+** see if those actions are allowed.  ^The authorizer callback should
+** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
+** specific action but allow the SQL statement to continue to be
+** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
+** rejected with an error.  ^If the authorizer callback returns
+** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
+** then the [sqlite3_prepare_v2()] or equivalent call that triggered
+** the authorizer will fail with an error message.
+**
+** When the callback returns [SQLITE_OK], that means the operation
+** requested is ok.  ^When the callback returns [SQLITE_DENY], the
+** [sqlite3_prepare_v2()] or equivalent call that triggered the
+** authorizer will fail with an error message explaining that
+** access is denied.
+**
+** ^The first parameter to the authorizer callback is a copy of the third
+** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
+** to the callback is an integer [SQLITE_COPY | action code] that specifies
+** the particular action to be authorized. ^The third through sixth parameters
+** to the callback are either NULL pointers or zero-terminated strings
+** that contain additional details about the action to be authorized.
+** Applications must always be prepared to encounter a NULL pointer in any
+** of the third through the sixth parameters of the authorization callback.
+**
+** ^If the action code is [SQLITE_READ]
+** and the callback returns [SQLITE_IGNORE] then the
+** [prepared statement] statement is constructed to substitute
+** a NULL value in place of the table column that would have
+** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
+** return can be used to deny an untrusted user access to individual
+** columns of a table.
+** ^When a table is referenced by a [SELECT] but no column values are
+** extracted from that table (for example in a query like
+** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
+** is invoked once for that table with a column name that is an empty string.
+** ^If the action code is [SQLITE_DELETE] and the callback returns
+** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
+** [truncate optimization] is disabled and all rows are deleted individually.
+**
+** An authorizer is used when [sqlite3_prepare | preparing]
+** SQL statements from an untrusted source, to ensure that the SQL statements
+** do not try to access data they are not allowed to see, or that they do not
+** try to execute malicious statements that damage the database.  For
+** example, an application may allow a user to enter arbitrary
+** SQL queries for evaluation by a database.  But the application does
+** not want the user to be able to make arbitrary changes to the
+** database.  An authorizer could then be put in place while the
+** user-entered SQL is being [sqlite3_prepare | prepared] that
+** disallows everything except [SELECT] statements.
+**
+** Applications that need to process SQL from untrusted sources
+** might also consider lowering resource limits using [sqlite3_limit()]
+** and limiting database size using the [max_page_count] [PRAGMA]
+** in addition to using an authorizer.
+**
+** ^(Only a single authorizer can be in place on a database connection
+** at a time.  Each call to sqlite3_set_authorizer overrides the
+** previous call.)^  ^Disable the authorizer by installing a NULL callback.
+** The authorizer is disabled by default.
+**
+** The authorizer callback must not do anything that will modify
+** the database connection that invoked the authorizer callback.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
+** statement might be re-prepared during [sqlite3_step()] due to a
+** schema change.  Hence, the application should ensure that the
+** correct authorizer callback remains in place during the [sqlite3_step()].
+**
+** ^Note that the authorizer callback is invoked only during
+** [sqlite3_prepare()] or its variants.  Authorization is not
+** performed during statement evaluation in [sqlite3_step()], unless
+** as stated in the previous paragraph, sqlite3_step() invokes
+** sqlite3_prepare_v2() to reprepare a statement after a schema change.
+*/
+SQLITE_API int sqlite3_set_authorizer(
+  sqlite3*,
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
+  void *pUserData
+);
+
+/*
+** CAPI3REF: Authorizer Return Codes
+**
+** The [sqlite3_set_authorizer | authorizer callback function] must
+** return either [SQLITE_OK] or one of these two constants in order
+** to signal SQLite whether or not the action is permitted.  See the
+** [sqlite3_set_authorizer | authorizer documentation] for additional
+** information.
+**
+** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
+** returned from the [sqlite3_vtab_on_conflict()] interface.
+*/
+#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
+#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
+
+/*
+** CAPI3REF: Authorizer Action Codes
+**
+** The [sqlite3_set_authorizer()] interface registers a callback function
+** that is invoked to authorize certain SQL statement actions.  The
+** second parameter to the callback is an integer code that specifies
+** what action is being authorized.  These are the integer action codes that
+** the authorizer callback may be passed.
+**
+** These action code values signify what kind of operation is to be
+** authorized.  The 3rd and 4th parameters to the authorization
+** callback function will be parameters or NULL depending on which of these
+** codes is used as the second parameter.  ^(The 5th parameter to the
+** authorizer callback is the name of the database ("main", "temp",
+** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
+** is the name of the inner-most trigger or view that is responsible for
+** the access attempt or NULL if this access attempt is directly from
+** top-level SQL code.
+*/
+/******************************************* 3rd ************ 4th ***********/
+#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
+#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
+#define SQLITE_DELETE                9   /* Table Name      NULL            */
+#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
+#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
+#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
+#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
+#define SQLITE_INSERT               18   /* Table Name      NULL            */
+#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
+#define SQLITE_READ                 20   /* Table Name      Column Name     */
+#define SQLITE_SELECT               21   /* NULL            NULL            */
+#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
+#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
+#define SQLITE_ATTACH               24   /* Filename        NULL            */
+#define SQLITE_DETACH               25   /* Database Name   NULL            */
+#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
+#define SQLITE_REINDEX              27   /* Index Name      NULL            */
+#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
+#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
+#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
+#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
+#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
+#define SQLITE_COPY                  0   /* No longer used */
+#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
+
+/*
+** CAPI3REF: Deprecated Tracing And Profiling Functions
+** DEPRECATED
+**
+** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
+** instead of the routines described here.
+**
+** These routines register callback functions that can be used for
+** tracing and profiling the execution of SQL statements.
+**
+** ^The callback function registered by sqlite3_trace() is invoked at
+** various times when an SQL statement is being run by [sqlite3_step()].
+** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
+** SQL statement text as the statement first begins executing.
+** ^(Additional sqlite3_trace() callbacks might occur
+** as each triggered subprogram is entered.  The callbacks for triggers
+** contain a UTF-8 SQL comment that identifies the trigger.)^
+**
+** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
+** the length of [bound parameter] expansion in the output of sqlite3_trace().
+**
+** ^The callback function registered by sqlite3_profile() is invoked
+** as each SQL statement finishes.  ^The profile callback contains
+** the original statement text and an estimate of wall-clock time
+** of how long that statement took to run.  ^The profile callback
+** time is in units of nanoseconds, however the current implementation
+** is only capable of millisecond resolution so the six least significant
+** digits in the time are meaningless.  Future versions of SQLite
+** might provide greater resolution on the profiler callback.  Invoking
+** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
+** profile callback.
+*/
+SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
+   void(*xTrace)(void*,const char*), void*);
+SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
+   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
+
+/*
+** CAPI3REF: SQL Trace Event Codes
+** KEYWORDS: SQLITE_TRACE
+**
+** These constants identify classes of events that can be monitored
+** using the [sqlite3_trace_v2()] tracing logic.  The M argument
+** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
+** the following constants.  ^The first argument to the trace callback
+** is one of the following constants.
+**
+** New tracing constants may be added in future releases.
+**
+** ^A trace callback has four arguments: xCallback(T,C,P,X).
+** ^The T argument is one of the integer type codes above.
+** ^The C argument is a copy of the context pointer passed in as the
+** fourth argument to [sqlite3_trace_v2()].
+** The P and X arguments are pointers whose meanings depend on T.
+**
+** <dl>
+** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
+** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
+** first begins running and possibly at other times during the
+** execution of the prepared statement, such as at the start of each
+** trigger subprogram. ^The P argument is a pointer to the
+** [prepared statement]. ^The X argument is a pointer to a string which
+** is the unexpanded SQL text of the prepared statement or an SQL comment
+** that indicates the invocation of a trigger.  ^The callback can compute
+** the same text that would have been returned by the legacy [sqlite3_trace()]
+** interface by using the X argument when X begins with "--" and invoking
+** [sqlite3_expanded_sql(P)] otherwise.
+**
+** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
+** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
+** information as is provided by the [sqlite3_profile()] callback.
+** ^The P argument is a pointer to the [prepared statement] and the
+** X argument points to a 64-bit integer which is approximately
+** the number of nanoseconds that the prepared statement took to run.
+** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
+**
+** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
+** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
+** statement generates a single row of result.
+** ^The P argument is a pointer to the [prepared statement] and the
+** X argument is unused.
+**
+** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
+** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
+** connection closes.
+** ^The P argument is a pointer to the [database connection] object
+** and the X argument is unused.
+** </dl>
+*/
+#define SQLITE_TRACE_STMT       0x01
+#define SQLITE_TRACE_PROFILE    0x02
+#define SQLITE_TRACE_ROW        0x04
+#define SQLITE_TRACE_CLOSE      0x08
+
+/*
+** CAPI3REF: SQL Trace Hook
+** METHOD: sqlite3
+**
+** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
+** function X against [database connection] D, using property mask M
+** and context pointer P.  ^If the X callback is
+** NULL or if the M mask is zero, then tracing is disabled.  The
+** M argument should be the bitwise OR-ed combination of
+** zero or more [SQLITE_TRACE] constants.
+**
+** ^Each call to either sqlite3_trace(D,X,P) or sqlite3_trace_v2(D,M,X,P)
+** overrides (cancels) all prior calls to sqlite3_trace(D,X,P) or
+** sqlite3_trace_v2(D,M,X,P) for the [database connection] D.  Each
+** database connection may have at most one trace callback.
+**
+** ^The X callback is invoked whenever any of the events identified by
+** mask M occur.  ^The integer return value from the callback is currently
+** ignored, though this may change in future releases.  Callback
+** implementations should return zero to ensure future compatibility.
+**
+** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
+** ^The T argument is one of the [SQLITE_TRACE]
+** constants to indicate why the callback was invoked.
+** ^The C argument is a copy of the context pointer.
+** The P and X arguments are pointers whose meanings depend on T.
+**
+** The sqlite3_trace_v2() interface is intended to replace the legacy
+** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
+** are deprecated.
+*/
+SQLITE_API int sqlite3_trace_v2(
+  sqlite3*,
+  unsigned uMask,
+  int(*xCallback)(unsigned,void*,void*,void*),
+  void *pCtx
+);
+
+/*
+** CAPI3REF: Query Progress Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
+** function X to be invoked periodically during long running calls to
+** [sqlite3_step()] and [sqlite3_prepare()] and similar for
+** database connection D.  An example use for this
+** interface is to keep a GUI updated during a large query.
+**
+** ^The parameter P is passed through as the only parameter to the
+** callback function X.  ^The parameter N is the approximate number of
+** [virtual machine instructions] that are evaluated between successive
+** invocations of the callback X.  ^If N is less than one then the progress
+** handler is disabled.
+**
+** ^Only a single progress handler may be defined at one time per
+** [database connection]; setting a new progress handler cancels the
+** old one.  ^Setting parameter X to NULL disables the progress handler.
+** ^The progress handler is also disabled by setting N to a value less
+** than 1.
+**
+** ^If the progress callback returns non-zero, the operation is
+** interrupted.  This feature can be used to implement a
+** "Cancel" button on a GUI progress dialog box.
+**
+** The progress handler callback must not do anything that will modify
+** the database connection that invoked the progress handler.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** The progress handler callback would originally only be invoked from the
+** bytecode engine.  It still might be invoked during [sqlite3_prepare()]
+** and similar because those routines might force a reparse of the schema
+** which involves running the bytecode engine.  However, beginning with
+** SQLite version 3.41.0, the progress handler callback might also be
+** invoked directly from [sqlite3_prepare()] while analyzing and generating
+** code for complex queries.
+*/
+SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
+
+/*
+** CAPI3REF: Opening A New Database Connection
+** CONSTRUCTOR: sqlite3
+**
+** ^These routines open an SQLite database file as specified by the
+** filename argument. ^The filename argument is interpreted as UTF-8 for
+** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
+** order for sqlite3_open16(). ^(A [database connection] handle is usually
+** returned in *ppDb, even if an error occurs.  The only exception is that
+** if SQLite is unable to allocate memory to hold the [sqlite3] object,
+** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
+** object.)^ ^(If the database is opened (and/or created) successfully, then
+** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
+** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
+** an English language description of the error following a failure of any
+** of the sqlite3_open() routines.
+**
+** ^The default encoding will be UTF-8 for databases created using
+** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
+** created using sqlite3_open16() will be UTF-16 in the native byte order.
+**
+** Whether or not an error occurs when it is opened, resources
+** associated with the [database connection] handle should be released by
+** passing it to [sqlite3_close()] when it is no longer required.
+**
+** The sqlite3_open_v2() interface works like sqlite3_open()
+** except that it accepts two additional parameters for additional control
+** over the new database connection.  ^(The flags parameter to
+** sqlite3_open_v2() must include, at a minimum, one of the following
+** three flag combinations:)^
+**
+** <dl>
+** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
+** <dd>The database is opened in read-only mode.  If the database does
+** not already exist, an error is returned.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
+** <dd>The database is opened for reading and writing if possible, or
+** reading only if the file is write protected by the operating
+** system.  In either case the database must already exist, otherwise
+** an error is returned.  For historical reasons, if opening in
+** read-write mode fails due to OS-level permissions, an attempt is
+** made to open it in read-only mode. [sqlite3_db_readonly()] can be
+** used to determine whether the database is actually
+** read-write.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
+** <dd>The database is opened for reading and writing, and is created if
+** it does not already exist. This is the behavior that is always used for
+** sqlite3_open() and sqlite3_open16().</dd>)^
+** </dl>
+**
+** In addition to the required flags, the following optional flags are
+** also supported:
+**
+** <dl>
+** ^(<dt>[SQLITE_OPEN_URI]</dt>
+** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
+** <dd>The database will be opened as an in-memory database.  The database
+** is named by the "filename" argument for the purposes of cache-sharing,
+** if shared cache mode is enabled, but the "filename" is otherwise ignored.
+** </dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
+** <dd>The new database connection will use the "multi-thread"
+** [threading mode].)^  This means that separate threads are allowed
+** to use SQLite at the same time, as long as each thread is using
+** a different [database connection].
+**
+** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
+** <dd>The new database connection will use the "serialized"
+** [threading mode].)^  This means the multiple threads can safely
+** attempt to use the same database connection at the same time.
+** (Mutexes will block any actual concurrency, but in this mode
+** there is no harm in trying.)
+**
+** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
+** <dd>The database is opened [shared cache] enabled, overriding
+** the default shared cache setting provided by
+** [sqlite3_enable_shared_cache()].)^
+** The [use of shared cache mode is discouraged] and hence shared cache
+** capabilities may be omitted from many builds of SQLite.  In such cases,
+** this option is a no-op.
+**
+** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
+** <dd>The database is opened [shared cache] disabled, overriding
+** the default shared cache setting provided by
+** [sqlite3_enable_shared_cache()].)^
+**
+** [[OPEN_EXRESCODE]] ^(<dt>[SQLITE_OPEN_EXRESCODE]</dt>
+** <dd>The database connection comes up in "extended result code mode".
+** In other words, the database behaves as if
+** [sqlite3_extended_result_codes(db,1)] were called on the database
+** connection as soon as the connection is created. In addition to setting
+** the extended result code mode, this flag also causes [sqlite3_open_v2()]
+** to return an extended result code.</dd>
+**
+** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
+** <dd>The database filename is not allowed to contain a symbolic link</dd>
+** </dl>)^
+**
+** If the 3rd parameter to sqlite3_open_v2() is not one of the
+** required combinations shown above optionally combined with other
+** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
+** then the behavior is undefined.  Historic versions of SQLite
+** have silently ignored surplus bits in the flags parameter to
+** sqlite3_open_v2(), however that behavior might not be carried through
+** into future versions of SQLite and so applications should not rely
+** upon it.  Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
+** for sqlite3_open_v2().  The SQLITE_OPEN_EXCLUSIVE does *not* cause
+** the open to fail if the database already exists.  The SQLITE_OPEN_EXCLUSIVE
+** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
+** by sqlite3_open_v2().
+**
+** ^The fourth parameter to sqlite3_open_v2() is the name of the
+** [sqlite3_vfs] object that defines the operating system interface that
+** the new database connection should use.  ^If the fourth parameter is
+** a NULL pointer then the default [sqlite3_vfs] object is used.
+**
+** ^If the filename is ":memory:", then a private, temporary in-memory database
+** is created for the connection.  ^This in-memory database will vanish when
+** the database connection is closed.  Future versions of SQLite might
+** make use of additional special filenames that begin with the ":" character.
+** It is recommended that when a database filename actually does begin with
+** a ":" character you should prefix the filename with a pathname such as
+** "./" to avoid ambiguity.
+**
+** ^If the filename is an empty string, then a private, temporary
+** on-disk database will be created.  ^This private database will be
+** automatically deleted as soon as the database connection is closed.
+**
+** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
+**
+** ^If [URI filename] interpretation is enabled, and the filename argument
+** begins with "file:", then the filename is interpreted as a URI. ^URI
+** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
+** set in the third argument to sqlite3_open_v2(), or if it has
+** been enabled globally using the [SQLITE_CONFIG_URI] option with the
+** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
+** URI filename interpretation is turned off
+** by default, but future releases of SQLite might enable URI filename
+** interpretation by default.  See "[URI filenames]" for additional
+** information.
+**
+** URI filenames are parsed according to RFC 3986. ^If the URI contains an
+** authority, then it must be either an empty string or the string
+** "localhost". ^If the authority is not an empty string or "localhost", an
+** error is returned to the caller. ^The fragment component of a URI, if
+** present, is ignored.
+**
+** ^SQLite uses the path component of the URI as the name of the disk file
+** which contains the database. ^If the path begins with a '/' character,
+** then it is interpreted as an absolute path. ^If the path does not begin
+** with a '/' (meaning that the authority section is omitted from the URI)
+** then the path is interpreted as a relative path.
+** ^(On windows, the first component of an absolute path
+** is a drive specification (e.g. "C:").)^
+**
+** [[core URI query parameters]]
+** The query component of a URI may contain parameters that are interpreted
+** either by SQLite itself, or by a [VFS | custom VFS implementation].
+** SQLite and its built-in [VFSes] interpret the
+** following query parameters:
+**
+** <ul>
+**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
+**     a VFS object that provides the operating system interface that should
+**     be used to access the database file on disk. ^If this option is set to
+**     an empty string the default VFS object is used. ^Specifying an unknown
+**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
+**     present, then the VFS specified by the option takes precedence over
+**     the value passed as the fourth parameter to sqlite3_open_v2().
+**
+**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
+**     "rwc", or "memory". Attempting to set it to any other value is
+**     an error)^.
+**     ^If "ro" is specified, then the database is opened for read-only
+**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
+**     third argument to sqlite3_open_v2(). ^If the mode option is set to
+**     "rw", then the database is opened for read-write (but not create)
+**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
+**     been set. ^Value "rwc" is equivalent to setting both
+**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
+**     set to "memory" then a pure [in-memory database] that never reads
+**     or writes from disk is used. ^It is an error to specify a value for
+**     the mode parameter that is less restrictive than that specified by
+**     the flags passed in the third parameter to sqlite3_open_v2().
+**
+**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
+**     "private". ^Setting it to "shared" is equivalent to setting the
+**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
+**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
+**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
+**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
+**     a URI filename, its value overrides any behavior requested by setting
+**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
+**
+**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
+**     [powersafe overwrite] property does or does not apply to the
+**     storage media on which the database file resides.
+**
+**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
+**     which if set disables file locking in rollback journal modes.  This
+**     is useful for accessing a database on a filesystem that does not
+**     support locking.  Caution:  Database corruption might result if two
+**     or more processes write to the same database and any one of those
+**     processes uses nolock=1.
+**
+**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
+**     parameter that indicates that the database file is stored on
+**     read-only media.  ^When immutable is set, SQLite assumes that the
+**     database file cannot be changed, even by a process with higher
+**     privilege, and so the database is opened read-only and all locking
+**     and change detection is disabled.  Caution: Setting the immutable
+**     property on a database file that does in fact change can result
+**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
+**     See also: [SQLITE_IOCAP_IMMUTABLE].
+**
+** </ul>
+**
+** ^Specifying an unknown parameter in the query component of a URI is not an
+** error.  Future versions of SQLite might understand additional query
+** parameters.  See "[query parameters with special meaning to SQLite]" for
+** additional information.
+**
+** [[URI filename examples]] <h3>URI filename examples</h3>
+**
+** <table border="1" align=center cellpadding=5>
+** <tr><th> URI filenames <th> Results
+** <tr><td> file:data.db <td>
+**          Open the file "data.db" in the current directory.
+** <tr><td> file:/home/fred/data.db<br>
+**          file:///home/fred/data.db <br>
+**          file://localhost/home/fred/data.db <br> <td>
+**          Open the database file "/home/fred/data.db".
+** <tr><td> file://darkstar/home/fred/data.db <td>
+**          An error. "darkstar" is not a recognized authority.
+** <tr><td style="white-space:nowrap">
+**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
+**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
+**          C:. Note that the %20 escaping in this example is not strictly
+**          necessary - space characters can be used literally
+**          in URI filenames.
+** <tr><td> file:data.db?mode=ro&cache=private <td>
+**          Open file "data.db" in the current directory for read-only access.
+**          Regardless of whether or not shared-cache mode is enabled by
+**          default, use a private cache.
+** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
+**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
+**          that uses dot-files in place of posix advisory locking.
+** <tr><td> file:data.db?mode=readonly <td>
+**          An error. "readonly" is not a valid option for the "mode" parameter.
+**          Use "ro" instead:  "file:data.db?mode=ro".
+** </table>
+**
+** ^URI hexadecimal escape sequences (%HH) are supported within the path and
+** query components of a URI. A hexadecimal escape sequence consists of a
+** percent sign - "%" - followed by exactly two hexadecimal digits
+** specifying an octet value. ^Before the path or query components of a
+** URI filename are interpreted, they are encoded using UTF-8 and all
+** hexadecimal escape sequences replaced by a single byte containing the
+** corresponding octet. If this process generates an invalid UTF-8 encoding,
+** the results are undefined.
+**
+** <b>Note to Windows users:</b>  The encoding used for the filename argument
+** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
+** codepage is currently defined.  Filenames containing international
+** characters must be converted to UTF-8 prior to passing them into
+** sqlite3_open() or sqlite3_open_v2().
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
+** features that require the use of temporary files may fail.
+**
+** See also: [sqlite3_temp_directory]
+*/
+SQLITE_API int sqlite3_open(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open16(
+  const void *filename,   /* Database filename (UTF-16) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open_v2(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb,         /* OUT: SQLite db handle */
+  int flags,              /* Flags */
+  const char *zVfs        /* Name of VFS module to use */
+);
+
+/*
+** CAPI3REF: Obtain Values For URI Parameters
+**
+** These are utility routines, useful to [VFS|custom VFS implementations],
+** that check if a database file was a URI that contained a specific query
+** parameter, and if so obtains the value of that query parameter.
+**
+** The first parameter to these interfaces (hereafter referred to
+** as F) must be one of:
+** <ul>
+** <li> A database filename pointer created by the SQLite core and
+** passed into the xOpen() method of a VFS implementation, or
+** <li> A filename obtained from [sqlite3_db_filename()], or
+** <li> A new filename constructed using [sqlite3_create_filename()].
+** </ul>
+** If the F parameter is not one of the above, then the behavior is
+** undefined and probably undesirable.  Older versions of SQLite were
+** more tolerant of invalid F parameters than newer versions.
+**
+** If F is a suitable filename (as described in the previous paragraph)
+** and if P is the name of the query parameter, then
+** sqlite3_uri_parameter(F,P) returns the value of the P
+** parameter if it exists or a NULL pointer if P does not appear as a
+** query parameter on F.  If P is a query parameter of F and it
+** has no explicit value, then sqlite3_uri_parameter(F,P) returns
+** a pointer to an empty string.
+**
+** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
+** parameter and returns true (1) or false (0) according to the value
+** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
+** value of query parameter P is one of "yes", "true", or "on" in any
+** case or if the value begins with a non-zero number.  The
+** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
+** query parameter P is one of "no", "false", or "off" in any case or
+** if the value begins with a numeric zero.  If P is not a query
+** parameter on F or if the value of P does not match any of the
+** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
+**
+** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
+** 64-bit signed integer and returns that integer, or D if P does not
+** exist.  If the value of P is something other than an integer, then
+** zero is returned.
+**
+** The sqlite3_uri_key(F,N) returns a pointer to the name (not
+** the value) of the N-th query parameter for filename F, or a NULL
+** pointer if N is less than zero or greater than the number of query
+** parameters minus 1.  The N value is zero-based so N should be 0 to obtain
+** the name of the first query parameter, 1 for the second parameter, and
+** so forth.
+**
+** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
+** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
+** is not a database file pathname pointer that the SQLite core passed
+** into the xOpen VFS method, then the behavior of this routine is undefined
+** and probably undesirable.
+**
+** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
+** parameter can also be the name of a rollback journal file or WAL file
+** in addition to the main database file.  Prior to version 3.31.0, these
+** routines would only work if F was the name of the main database file.
+** When the F parameter is the name of the rollback journal or WAL file,
+** it has access to all the same query parameters as were found on the
+** main database file.
+**
+** See the [URI filename] documentation for additional information.
+*/
+SQLITE_API const char *sqlite3_uri_parameter(sqlite3_filename z, const char *zParam);
+SQLITE_API int sqlite3_uri_boolean(sqlite3_filename z, const char *zParam, int bDefault);
+SQLITE_API sqlite3_int64 sqlite3_uri_int64(sqlite3_filename, const char*, sqlite3_int64);
+SQLITE_API const char *sqlite3_uri_key(sqlite3_filename z, int N);
+
+/*
+** CAPI3REF:  Translate filenames
+**
+** These routines are available to [VFS|custom VFS implementations] for
+** translating filenames between the main database file, the journal file,
+** and the WAL file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
+** returns the name of the corresponding database file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** passed by the SQLite core into the VFS, or if F is a database filename
+** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
+** returns the name of the corresponding rollback journal file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** that was passed by the SQLite core into the VFS, or if F is a database
+** filename obtained from [sqlite3_db_filename()], then
+** sqlite3_filename_wal(F) returns the name of the corresponding
+** WAL file.
+**
+** In all of the above, if F is not the name of a database, journal or WAL
+** filename passed into the VFS from the SQLite core and F is not the
+** return value from [sqlite3_db_filename()], then the result is
+** undefined and is likely a memory access violation.
+*/
+SQLITE_API const char *sqlite3_filename_database(sqlite3_filename);
+SQLITE_API const char *sqlite3_filename_journal(sqlite3_filename);
+SQLITE_API const char *sqlite3_filename_wal(sqlite3_filename);
+
+/*
+** CAPI3REF:  Database File Corresponding To A Journal
+**
+** ^If X is the name of a rollback or WAL-mode journal file that is
+** passed into the xOpen method of [sqlite3_vfs], then
+** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
+** object that represents the main database file.
+**
+** This routine is intended for use in custom [VFS] implementations
+** only.  It is not a general-purpose interface.
+** The argument sqlite3_file_object(X) must be a filename pointer that
+** has been passed into [sqlite3_vfs].xOpen method where the
+** flags parameter to xOpen contains one of the bits
+** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL].  Any other use
+** of this routine results in undefined and probably undesirable
+** behavior.
+*/
+SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
+
+/*
+** CAPI3REF: Create and Destroy VFS Filenames
+**
+** These interfaces are provided for use by [VFS shim] implementations and
+** are not useful outside of that context.
+**
+** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
+** database filename D with corresponding journal file J and WAL file W and
+** with N URI parameters key/values pairs in the array P.  The result from
+** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
+** is safe to pass to routines like:
+** <ul>
+** <li> [sqlite3_uri_parameter()],
+** <li> [sqlite3_uri_boolean()],
+** <li> [sqlite3_uri_int64()],
+** <li> [sqlite3_uri_key()],
+** <li> [sqlite3_filename_database()],
+** <li> [sqlite3_filename_journal()], or
+** <li> [sqlite3_filename_wal()].
+** </ul>
+** If a memory allocation error occurs, sqlite3_create_filename() might
+** return a NULL pointer.  The memory obtained from sqlite3_create_filename(X)
+** must be released by a corresponding call to sqlite3_free_filename(Y).
+**
+** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
+** of 2*N pointers to strings.  Each pair of pointers in this array corresponds
+** to a key and value for a query parameter.  The P parameter may be a NULL
+** pointer if N is zero.  None of the 2*N pointers in the P array may be
+** NULL pointers and key pointers should not be empty strings.
+** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
+** be NULL pointers, though they can be empty strings.
+**
+** The sqlite3_free_filename(Y) routine releases a memory allocation
+** previously obtained from sqlite3_create_filename().  Invoking
+** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
+**
+** If the Y parameter to sqlite3_free_filename(Y) is anything other
+** than a NULL pointer or a pointer previously acquired from
+** sqlite3_create_filename(), then bad things such as heap
+** corruption or segfaults may occur. The value Y should not be
+** used again after sqlite3_free_filename(Y) has been called.  This means
+** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
+** then the corresponding [sqlite3_module.xClose() method should also be
+** invoked prior to calling sqlite3_free_filename(Y).
+*/
+SQLITE_API sqlite3_filename sqlite3_create_filename(
+  const char *zDatabase,
+  const char *zJournal,
+  const char *zWal,
+  int nParam,
+  const char **azParam
+);
+SQLITE_API void sqlite3_free_filename(sqlite3_filename);
+
+/*
+** CAPI3REF: Error Codes And Messages
+** METHOD: sqlite3
+**
+** ^If the most recent sqlite3_* API call associated with
+** [database connection] D failed, then the sqlite3_errcode(D) interface
+** returns the numeric [result code] or [extended result code] for that
+** API call.
+** ^The sqlite3_extended_errcode()
+** interface is the same except that it always returns the
+** [extended result code] even when extended result codes are
+** disabled.
+**
+** The values returned by sqlite3_errcode() and/or
+** sqlite3_extended_errcode() might change with each API call.
+** Except, there are some interfaces that are guaranteed to never
+** change the value of the error code.  The error-code preserving
+** interfaces include the following:
+**
+** <ul>
+** <li> sqlite3_errcode()
+** <li> sqlite3_extended_errcode()
+** <li> sqlite3_errmsg()
+** <li> sqlite3_errmsg16()
+** <li> sqlite3_error_offset()
+** </ul>
+**
+** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
+** text that describes the error, as either UTF-8 or UTF-16 respectively,
+** or NULL if no error message is available.
+** (See how SQLite handles [invalid UTF] for exceptions to this rule.)
+** ^(Memory to hold the error message string is managed internally.
+** The application does not need to worry about freeing the result.
+** However, the error string might be overwritten or deallocated by
+** subsequent calls to other SQLite interface functions.)^
+**
+** ^The sqlite3_errstr(E) interface returns the English-language text
+** that describes the [result code] E, as UTF-8, or NULL if E is not an
+** result code for which a text error message is available.
+** ^(Memory to hold the error message string is managed internally
+** and must not be freed by the application)^.
+**
+** ^If the most recent error references a specific token in the input
+** SQL, the sqlite3_error_offset() interface returns the byte offset
+** of the start of that token.  ^The byte offset returned by
+** sqlite3_error_offset() assumes that the input SQL is UTF8.
+** ^If the most recent error does not reference a specific token in the input
+** SQL, then the sqlite3_error_offset() function returns -1.
+**
+** When the serialized [threading mode] is in use, it might be the
+** case that a second error occurs on a separate thread in between
+** the time of the first error and the call to these interfaces.
+** When that happens, the second error will be reported since these
+** interfaces always report the most recent result.  To avoid
+** this, each thread can obtain exclusive use of the [database connection] D
+** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
+** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
+** all calls to the interfaces listed here are completed.
+**
+** If an interface fails with SQLITE_MISUSE, that means the interface
+** was invoked incorrectly by the application.  In that case, the
+** error code and message may or may not be set.
+*/
+SQLITE_API int sqlite3_errcode(sqlite3 *db);
+SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
+SQLITE_API const char *sqlite3_errmsg(sqlite3*);
+SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
+SQLITE_API const char *sqlite3_errstr(int);
+SQLITE_API int sqlite3_error_offset(sqlite3 *db);
+
+/*
+** CAPI3REF: Prepared Statement Object
+** KEYWORDS: {prepared statement} {prepared statements}
+**
+** An instance of this object represents a single SQL statement that
+** has been compiled into binary form and is ready to be evaluated.
+**
+** Think of each SQL statement as a separate computer program.  The
+** original SQL text is source code.  A prepared statement object
+** is the compiled object code.  All SQL must be converted into a
+** prepared statement before it can be run.
+**
+** The life-cycle of a prepared statement object usually goes like this:
+**
+** <ol>
+** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
+** <li> Bind values to [parameters] using the sqlite3_bind_*()
+**      interfaces.
+** <li> Run the SQL by calling [sqlite3_step()] one or more times.
+** <li> Reset the prepared statement using [sqlite3_reset()] then go back
+**      to step 2.  Do this zero or more times.
+** <li> Destroy the object using [sqlite3_finalize()].
+** </ol>
+*/
+typedef struct sqlite3_stmt sqlite3_stmt;
+
+/*
+** CAPI3REF: Run-time Limits
+** METHOD: sqlite3
+**
+** ^(This interface allows the size of various constructs to be limited
+** on a connection by connection basis.  The first parameter is the
+** [database connection] whose limit is to be set or queried.  The
+** second parameter is one of the [limit categories] that define a
+** class of constructs to be size limited.  The third parameter is the
+** new limit for that construct.)^
+**
+** ^If the new limit is a negative number, the limit is unchanged.
+** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
+** [limits | hard upper bound]
+** set at compile-time by a C preprocessor macro called
+** [limits | SQLITE_MAX_<i>NAME</i>].
+** (The "_LIMIT_" in the name is changed to "_MAX_".))^
+** ^Attempts to increase a limit above its hard upper bound are
+** silently truncated to the hard upper bound.
+**
+** ^Regardless of whether or not the limit was changed, the
+** [sqlite3_limit()] interface returns the prior value of the limit.
+** ^Hence, to find the current value of a limit without changing it,
+** simply invoke this interface with the third parameter set to -1.
+**
+** Run-time limits are intended for use in applications that manage
+** both their own internal database and also databases that are controlled
+** by untrusted external sources.  An example application might be a
+** web browser that has its own databases for storing history and
+** separate databases controlled by JavaScript applications downloaded
+** off the Internet.  The internal databases can be given the
+** large, default limits.  Databases managed by external sources can
+** be given much smaller limits designed to prevent a denial of service
+** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
+** interface to further control untrusted SQL.  The size of the database
+** created by an untrusted script can be contained using the
+** [max_page_count] [PRAGMA].
+**
+** New run-time limit categories may be added in future releases.
+*/
+SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
+
+/*
+** CAPI3REF: Run-Time Limit Categories
+** KEYWORDS: {limit category} {*limit categories}
+**
+** These constants define various performance limits
+** that can be lowered at run-time using [sqlite3_limit()].
+** The synopsis of the meanings of the various limits is shown below.
+** Additional information is available at [limits | Limits in SQLite].
+**
+** <dl>
+** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
+** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
+**
+** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
+** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
+**
+** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
+** <dd>The maximum number of columns in a table definition or in the
+** result set of a [SELECT] or the maximum number of columns in an index
+** or in an ORDER BY or GROUP BY clause.</dd>)^
+**
+** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
+** <dd>The maximum depth of the parse tree on any expression.</dd>)^
+**
+** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
+** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
+**
+** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
+** <dd>The maximum number of instructions in a virtual machine program
+** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
+** the equivalent tries to allocate space for more than this many opcodes
+** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
+**
+** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
+** <dd>The maximum number of arguments on a function.</dd>)^
+**
+** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
+** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
+**
+** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
+** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
+** <dd>The maximum length of the pattern argument to the [LIKE] or
+** [GLOB] operators.</dd>)^
+**
+** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
+** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
+** <dd>The maximum index number of any [parameter] in an SQL statement.)^
+**
+** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
+** <dd>The maximum depth of recursion for triggers.</dd>)^
+**
+** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
+** <dd>The maximum number of auxiliary worker threads that a single
+** [prepared statement] may start.</dd>)^
+** </dl>
+*/
+#define SQLITE_LIMIT_LENGTH                    0
+#define SQLITE_LIMIT_SQL_LENGTH                1
+#define SQLITE_LIMIT_COLUMN                    2
+#define SQLITE_LIMIT_EXPR_DEPTH                3
+#define SQLITE_LIMIT_COMPOUND_SELECT           4
+#define SQLITE_LIMIT_VDBE_OP                   5
+#define SQLITE_LIMIT_FUNCTION_ARG              6
+#define SQLITE_LIMIT_ATTACHED                  7
+#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
+#define SQLITE_LIMIT_VARIABLE_NUMBER           9
+#define SQLITE_LIMIT_TRIGGER_DEPTH            10
+#define SQLITE_LIMIT_WORKER_THREADS           11
+
+/*
+** CAPI3REF: Prepare Flags
+**
+** These constants define various flags that can be passed into
+** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
+** [sqlite3_prepare16_v3()] interfaces.
+**
+** New flags may be added in future releases of SQLite.
+**
+** <dl>
+** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
+** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
+** that the prepared statement will be retained for a long time and
+** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
+** and [sqlite3_prepare16_v3()] assume that the prepared statement will
+** be used just once or at most a few times and then destroyed using
+** [sqlite3_finalize()] relatively soon. The current implementation acts
+** on this hint by avoiding the use of [lookaside memory] so as not to
+** deplete the limited store of lookaside memory. Future versions of
+** SQLite may act on this hint differently.
+**
+** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
+** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
+** to be required for any prepared statement that wanted to use the
+** [sqlite3_normalized_sql()] interface.  However, the
+** [sqlite3_normalized_sql()] interface is now available to all
+** prepared statements, regardless of whether or not they use this
+** flag.
+**
+** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
+** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
+** to return an error (error code SQLITE_ERROR) if the statement uses
+** any virtual tables.
+**
+** [[SQLITE_PREPARE_DONT_LOG]] <dt>SQLITE_PREPARE_DONT_LOG</dt>
+** <dd>The SQLITE_PREPARE_DONT_LOG flag prevents SQL compiler
+** errors from being sent to the error log defined by
+** [SQLITE_CONFIG_LOG].  This can be used, for example, to do test
+** compiles to see if some SQL syntax is well-formed, without generating
+** messages on the global error log when it is not.  If the test compile
+** fails, the sqlite3_prepare_v3() call returns the same error indications
+** with or without this flag; it just omits the call to [sqlite3_log()] that
+** logs the error.
+** </dl>
+*/
+#define SQLITE_PREPARE_PERSISTENT              0x01
+#define SQLITE_PREPARE_NORMALIZE               0x02
+#define SQLITE_PREPARE_NO_VTAB                 0x04
+#define SQLITE_PREPARE_DONT_LOG                0x10
+
+/*
+** CAPI3REF: Compiling An SQL Statement
+** KEYWORDS: {SQL statement compiler}
+** METHOD: sqlite3
+** CONSTRUCTOR: sqlite3_stmt
+**
+** To execute an SQL statement, it must first be compiled into a byte-code
+** program using one of these routines.  Or, in other words, these routines
+** are constructors for the [prepared statement] object.
+**
+** The preferred routine to use is [sqlite3_prepare_v2()].  The
+** [sqlite3_prepare()] interface is legacy and should be avoided.
+** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
+** for special purposes.
+**
+** The use of the UTF-8 interfaces is preferred, as SQLite currently
+** does all parsing using UTF-8.  The UTF-16 interfaces are provided
+** as a convenience.  The UTF-16 interfaces work by converting the
+** input text into UTF-8, then invoking the corresponding UTF-8 interface.
+**
+** The first argument, "db", is a [database connection] obtained from a
+** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
+** [sqlite3_open16()].  The database connection must not have been closed.
+**
+** The second argument, "zSql", is the statement to be compiled, encoded
+** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
+** and sqlite3_prepare_v3()
+** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
+** and sqlite3_prepare16_v3() use UTF-16.
+**
+** ^If the nByte argument is negative, then zSql is read up to the
+** first zero terminator. ^If nByte is positive, then it is the maximum
+** number of bytes read from zSql.  When nByte is positive, zSql is read
+** up to the first zero terminator or until the nByte bytes have been read,
+** whichever comes first.  ^If nByte is zero, then no prepared
+** statement is generated.
+** If the caller knows that the supplied string is nul-terminated, then
+** there is a small performance advantage to passing an nByte parameter that
+** is the number of bytes in the input string <i>including</i>
+** the nul-terminator.
+** Note that nByte measure the length of the input in bytes, not
+** characters, even for the UTF-16 interfaces.
+**
+** ^If pzTail is not NULL then *pzTail is made to point to the first byte
+** past the end of the first SQL statement in zSql.  These routines only
+** compile the first statement in zSql, so *pzTail is left pointing to
+** what remains uncompiled.
+**
+** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
+** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
+** to NULL.  ^If the input text contains no SQL (if the input is an empty
+** string or a comment) then *ppStmt is set to NULL.
+** The calling procedure is responsible for deleting the compiled
+** SQL statement using [sqlite3_finalize()] after it has finished with it.
+** ppStmt may not be NULL.
+**
+** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
+** otherwise an [error code] is returned.
+**
+** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
+** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
+** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
+** are retained for backwards compatibility, but their use is discouraged.
+** ^In the "vX" interfaces, the prepared statement
+** that is returned (the [sqlite3_stmt] object) contains a copy of the
+** original SQL text. This causes the [sqlite3_step()] interface to
+** behave differently in three ways:
+**
+** <ol>
+** <li>
+** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
+** always used to do, [sqlite3_step()] will automatically recompile the SQL
+** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
+** retries will occur before sqlite3_step() gives up and returns an error.
+** </li>
+**
+** <li>
+** ^When an error occurs, [sqlite3_step()] will return one of the detailed
+** [error codes] or [extended error codes].  ^The legacy behavior was that
+** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
+** and the application would have to make a second call to [sqlite3_reset()]
+** in order to find the underlying cause of the problem. With the "v2" prepare
+** interfaces, the underlying reason for the error is returned immediately.
+** </li>
+**
+** <li>
+** ^If the specific value bound to a [parameter | host parameter] in the
+** WHERE clause might influence the choice of query plan for a statement,
+** then the statement will be automatically recompiled, as if there had been
+** a schema change, on the first [sqlite3_step()] call following any change
+** to the [sqlite3_bind_text | bindings] of that [parameter].
+** ^The specific value of a WHERE-clause [parameter] might influence the
+** choice of query plan if the parameter is the left-hand side of a [LIKE]
+** or [GLOB] operator or if the parameter is compared to an indexed column
+** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
+** </li>
+** </ol>
+**
+** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
+** the extra prepFlags parameter, which is a bit array consisting of zero or
+** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
+** sqlite3_prepare_v2() interface works exactly the same as
+** sqlite3_prepare_v3() with a zero prepFlags parameter.
+*/
+SQLITE_API int sqlite3_prepare(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare_v2(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare_v3(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16_v2(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16_v3(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+
+/*
+** CAPI3REF: Retrieving Statement SQL
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
+** SQL text used to create [prepared statement] P if P was
+** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
+** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
+** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
+** string containing the SQL text of prepared statement P with
+** [bound parameters] expanded.
+** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
+** string containing the normalized SQL text of prepared statement P.  The
+** semantics used to normalize a SQL statement are unspecified and subject
+** to change.  At a minimum, literal values will be replaced with suitable
+** placeholders.
+**
+** ^(For example, if a prepared statement is created using the SQL
+** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
+** and parameter :xyz is unbound, then sqlite3_sql() will return
+** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
+** will return "SELECT 2345,NULL".)^
+**
+** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
+** is available to hold the result, or if the result would exceed the
+** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
+**
+** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
+** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
+** option causes sqlite3_expanded_sql() to always return NULL.
+**
+** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
+** are managed by SQLite and are automatically freed when the prepared
+** statement is finalized.
+** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
+** is obtained from [sqlite3_malloc()] and must be freed by the application
+** by passing it to [sqlite3_free()].
+**
+** ^The sqlite3_normalized_sql() interface is only available if
+** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
+*/
+SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
+SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
+#ifdef SQLITE_ENABLE_NORMALIZE
+SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
+#endif
+
+/*
+** CAPI3REF: Determine If An SQL Statement Writes The Database
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
+** and only if the [prepared statement] X makes no direct changes to
+** the content of the database file.
+**
+** Note that [application-defined SQL functions] or
+** [virtual tables] might change the database indirectly as a side effect.
+** ^(For example, if an application defines a function "eval()" that
+** calls [sqlite3_exec()], then the following SQL statement would
+** change the database file through side-effects:
+**
+** <blockquote><pre>
+**    SELECT eval('DELETE FROM t1') FROM t2;
+** </pre></blockquote>
+**
+** But because the [SELECT] statement does not change the database file
+** directly, sqlite3_stmt_readonly() would still return true.)^
+**
+** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
+** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
+** since the statements themselves do not actually modify the database but
+** rather they control the timing of when other statements modify the
+** database.  ^The [ATTACH] and [DETACH] statements also cause
+** sqlite3_stmt_readonly() to return true since, while those statements
+** change the configuration of a database connection, they do not make
+** changes to the content of the database files on disk.
+** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
+** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
+** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
+** sqlite3_stmt_readonly() returns false for those commands.
+**
+** ^This routine returns false if there is any possibility that the
+** statement might change the database file.  ^A false return does
+** not guarantee that the statement will change the database file.
+** ^For example, an UPDATE statement might have a WHERE clause that
+** makes it a no-op, but the sqlite3_stmt_readonly() result would still
+** be false.  ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
+** read-only no-op if the table already exists, but
+** sqlite3_stmt_readonly() still returns false for such a statement.
+**
+** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
+** statement, then sqlite3_stmt_readonly(X) returns the same value as
+** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
+*/
+SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
+** prepared statement S is an EXPLAIN statement, or 2 if the
+** statement S is an EXPLAIN QUERY PLAN.
+** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
+** an ordinary statement or a NULL pointer.
+*/
+SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Change The EXPLAIN Setting For A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** The sqlite3_stmt_explain(S,E) interface changes the EXPLAIN
+** setting for [prepared statement] S.  If E is zero, then S becomes
+** a normal prepared statement.  If E is 1, then S behaves as if
+** its SQL text began with "[EXPLAIN]".  If E is 2, then S behaves as if
+** its SQL text began with "[EXPLAIN QUERY PLAN]".
+**
+** Calling sqlite3_stmt_explain(S,E) might cause S to be reprepared.
+** SQLite tries to avoid a reprepare, but a reprepare might be necessary
+** on the first transition into EXPLAIN or EXPLAIN QUERY PLAN mode.
+**
+** Because of the potential need to reprepare, a call to
+** sqlite3_stmt_explain(S,E) will fail with SQLITE_ERROR if S cannot be
+** reprepared because it was created using [sqlite3_prepare()] instead of
+** the newer [sqlite3_prepare_v2()] or [sqlite3_prepare_v3()] interfaces and
+** hence has no saved SQL text with which to reprepare.
+**
+** Changing the explain setting for a prepared statement does not change
+** the original SQL text for the statement.  Hence, if the SQL text originally
+** began with EXPLAIN or EXPLAIN QUERY PLAN, but sqlite3_stmt_explain(S,0)
+** is called to convert the statement into an ordinary statement, the EXPLAIN
+** or EXPLAIN QUERY PLAN keywords will still appear in the sqlite3_sql(S)
+** output, even though the statement now acts like a normal SQL statement.
+**
+** This routine returns SQLITE_OK if the explain mode is successfully
+** changed, or an error code if the explain mode could not be changed.
+** The explain mode cannot be changed while a statement is active.
+** Hence, it is good practice to call [sqlite3_reset(S)]
+** immediately prior to calling sqlite3_stmt_explain(S,E).
+*/
+SQLITE_API int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode);
+
+/*
+** CAPI3REF: Determine If A Prepared Statement Has Been Reset
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
+** [prepared statement] S has been stepped at least once using
+** [sqlite3_step(S)] but has neither run to completion (returned
+** [SQLITE_DONE] from [sqlite3_step(S)]) nor
+** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
+** interface returns false if S is a NULL pointer.  If S is not a
+** NULL pointer and is not a pointer to a valid [prepared statement]
+** object, then the behavior is undefined and probably undesirable.
+**
+** This interface can be used in combination [sqlite3_next_stmt()]
+** to locate all prepared statements associated with a database
+** connection that are in need of being reset.  This can be used,
+** for example, in diagnostic routines to search for prepared
+** statements that are holding a transaction open.
+*/
+SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Dynamically Typed Value Object
+** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
+**
+** SQLite uses the sqlite3_value object to represent all values
+** that can be stored in a database table. SQLite uses dynamic typing
+** for the values it stores.  ^Values stored in sqlite3_value objects
+** can be integers, floating point values, strings, BLOBs, or NULL.
+**
+** An sqlite3_value object may be either "protected" or "unprotected".
+** Some interfaces require a protected sqlite3_value.  Other interfaces
+** will accept either a protected or an unprotected sqlite3_value.
+** Every interface that accepts sqlite3_value arguments specifies
+** whether or not it requires a protected sqlite3_value.  The
+** [sqlite3_value_dup()] interface can be used to construct a new
+** protected sqlite3_value from an unprotected sqlite3_value.
+**
+** The terms "protected" and "unprotected" refer to whether or not
+** a mutex is held.  An internal mutex is held for a protected
+** sqlite3_value object but no mutex is held for an unprotected
+** sqlite3_value object.  If SQLite is compiled to be single-threaded
+** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
+** or if SQLite is run in one of reduced mutex modes
+** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
+** then there is no distinction between protected and unprotected
+** sqlite3_value objects and they can be used interchangeably.  However,
+** for maximum code portability it is recommended that applications
+** still make the distinction between protected and unprotected
+** sqlite3_value objects even when not strictly required.
+**
+** ^The sqlite3_value objects that are passed as parameters into the
+** implementation of [application-defined SQL functions] are protected.
+** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
+** are protected.
+** ^The sqlite3_value object returned by
+** [sqlite3_column_value()] is unprotected.
+** Unprotected sqlite3_value objects may only be used as arguments
+** to [sqlite3_result_value()], [sqlite3_bind_value()], and
+** [sqlite3_value_dup()].
+** The [sqlite3_value_blob | sqlite3_value_type()] family of
+** interfaces require protected sqlite3_value objects.
+*/
+typedef struct sqlite3_value sqlite3_value;
+
+/*
+** CAPI3REF: SQL Function Context Object
+**
+** The context in which an SQL function executes is stored in an
+** sqlite3_context object.  ^A pointer to an sqlite3_context object
+** is always first parameter to [application-defined SQL functions].
+** The application-defined SQL function implementation will pass this
+** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
+** [sqlite3_aggregate_context()], [sqlite3_user_data()],
+** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
+** and/or [sqlite3_set_auxdata()].
+*/
+typedef struct sqlite3_context sqlite3_context;
+
+/*
+** CAPI3REF: Binding Values To Prepared Statements
+** KEYWORDS: {host parameter} {host parameters} {host parameter name}
+** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
+** METHOD: sqlite3_stmt
+**
+** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
+** literals may be replaced by a [parameter] that matches one of following
+** templates:
+**
+** <ul>
+** <li>  ?
+** <li>  ?NNN
+** <li>  :VVV
+** <li>  @VVV
+** <li>  $VVV
+** </ul>
+**
+** In the templates above, NNN represents an integer literal,
+** and VVV represents an alphanumeric identifier.)^  ^The values of these
+** parameters (also called "host parameter names" or "SQL parameters")
+** can be set using the sqlite3_bind_*() routines defined here.
+**
+** ^The first argument to the sqlite3_bind_*() routines is always
+** a pointer to the [sqlite3_stmt] object returned from
+** [sqlite3_prepare_v2()] or its variants.
+**
+** ^The second argument is the index of the SQL parameter to be set.
+** ^The leftmost SQL parameter has an index of 1.  ^When the same named
+** SQL parameter is used more than once, second and subsequent
+** occurrences have the same index as the first occurrence.
+** ^The index for named parameters can be looked up using the
+** [sqlite3_bind_parameter_index()] API if desired.  ^The index
+** for "?NNN" parameters is the value of NNN.
+** ^The NNN value must be between 1 and the [sqlite3_limit()]
+** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
+**
+** ^The third argument is the value to bind to the parameter.
+** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
+** is ignored and the end result is the same as sqlite3_bind_null().
+** ^If the third parameter to sqlite3_bind_text() is not NULL, then
+** it should be a pointer to well-formed UTF8 text.
+** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
+** it should be a pointer to well-formed UTF16 text.
+** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
+** it should be a pointer to a well-formed unicode string that is
+** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
+** otherwise.
+**
+** [[byte-order determination rules]] ^The byte-order of
+** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
+** found in first character, which is removed, or in the absence of a BOM
+** the byte order is the native byte order of the host
+** machine for sqlite3_bind_text16() or the byte order specified in
+** the 6th parameter for sqlite3_bind_text64().)^
+** ^If UTF16 input text contains invalid unicode
+** characters, then SQLite might change those invalid characters
+** into the unicode replacement character: U+FFFD.
+**
+** ^(In those routines that have a fourth argument, its value is the
+** number of bytes in the parameter.  To be clear: the value is the
+** number of <u>bytes</u> in the value, not the number of characters.)^
+** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** is negative, then the length of the string is
+** the number of bytes up to the first zero terminator.
+** If the fourth parameter to sqlite3_bind_blob() is negative, then
+** the behavior is undefined.
+** If a non-negative fourth parameter is provided to sqlite3_bind_text()
+** or sqlite3_bind_text16() or sqlite3_bind_text64() then
+** that parameter must be the byte offset
+** where the NUL terminator would occur assuming the string were NUL
+** terminated.  If any NUL characters occurs at byte offsets less than
+** the value of the fourth parameter then the resulting string value will
+** contain embedded NULs.  The result of expressions involving strings
+** with embedded NULs is undefined.
+**
+** ^The fifth argument to the BLOB and string binding interfaces controls
+** or indicates the lifetime of the object referenced by the third parameter.
+** These three options exist:
+** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
+** with it may be passed. ^It is called to dispose of the BLOB or string even
+** if the call to the bind API fails, except the destructor is not called if
+** the third parameter is a NULL pointer or the fourth parameter is negative.
+** ^ (2) The special constant, [SQLITE_STATIC], may be passed to indicate that
+** the application remains responsible for disposing of the object. ^In this
+** case, the object and the provided pointer to it must remain valid until
+** either the prepared statement is finalized or the same SQL parameter is
+** bound to something else, whichever occurs sooner.
+** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
+** object is to be copied prior to the return from sqlite3_bind_*(). ^The
+** object and pointer to it must remain valid until then. ^SQLite will then
+** manage the lifetime of its private copy.
+**
+** ^The sixth argument to sqlite3_bind_text64() must be one of
+** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
+** to specify the encoding of the text in the third parameter.  If
+** the sixth argument to sqlite3_bind_text64() is not one of the
+** allowed values shown above, or if the text encoding is different
+** from the encoding specified by the sixth parameter, then the behavior
+** is undefined.
+**
+** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
+** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
+** (just an integer to hold its size) while it is being processed.
+** Zeroblobs are intended to serve as placeholders for BLOBs whose
+** content is later written using
+** [sqlite3_blob_open | incremental BLOB I/O] routines.
+** ^A negative value for the zeroblob results in a zero-length BLOB.
+**
+** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
+** [prepared statement] S to have an SQL value of NULL, but to also be
+** associated with the pointer P of type T.  ^D is either a NULL pointer or
+** a pointer to a destructor function for P. ^SQLite will invoke the
+** destructor D with a single argument of P when it is finished using
+** P.  The T parameter should be a static string, preferably a string
+** literal. The sqlite3_bind_pointer() routine is part of the
+** [pointer passing interface] added for SQLite 3.20.0.
+**
+** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
+** for the [prepared statement] or with a prepared statement for which
+** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
+** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
+** routine is passed a [prepared statement] that has been finalized, the
+** result is undefined and probably harmful.
+**
+** ^Bindings are not cleared by the [sqlite3_reset()] routine.
+** ^Unbound parameters are interpreted as NULL.
+**
+** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
+** [error code] if anything goes wrong.
+** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
+** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
+** [SQLITE_MAX_LENGTH].
+** ^[SQLITE_RANGE] is returned if the parameter
+** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
+**
+** See also: [sqlite3_bind_parameter_count()],
+** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
+SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
+                        void(*)(void*));
+SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
+SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
+SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
+SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
+SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
+SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
+SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
+                         void(*)(void*), unsigned char encoding);
+SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
+SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
+SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
+SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
+
+/*
+** CAPI3REF: Number Of SQL Parameters
+** METHOD: sqlite3_stmt
+**
+** ^This routine can be used to find the number of [SQL parameters]
+** in a [prepared statement].  SQL parameters are tokens of the
+** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
+** placeholders for values that are [sqlite3_bind_blob | bound]
+** to the parameters at a later time.
+**
+** ^(This routine actually returns the index of the largest (rightmost)
+** parameter. For all forms except ?NNN, this will correspond to the
+** number of unique parameters.  If parameters of the ?NNN form are used,
+** there may be gaps in the list.)^
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_name()], and
+** [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Name Of A Host Parameter
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_bind_parameter_name(P,N) interface returns
+** the name of the N-th [SQL parameter] in the [prepared statement] P.
+** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** respectively.
+** In other words, the initial ":" or "$" or "@" or "?"
+** is included as part of the name.)^
+** ^Parameters of the form "?" without a following integer have no name
+** and are referred to as "nameless" or "anonymous parameters".
+**
+** ^The first host parameter has an index of 1, not 0.
+**
+** ^If the value N is out of range or if the N-th parameter is
+** nameless, then NULL is returned.  ^The returned string is
+** always in UTF-8 encoding even if the named parameter was
+** originally specified as UTF-16 in [sqlite3_prepare16()],
+** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
+
+/*
+** CAPI3REF: Index Of A Parameter With A Given Name
+** METHOD: sqlite3_stmt
+**
+** ^Return the index of an SQL parameter given its name.  ^The
+** index value returned is suitable for use as the second
+** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
+** is returned if no matching parameter is found.  ^The parameter
+** name must be given in UTF-8 even if the original statement
+** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
+** [sqlite3_prepare16_v3()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_name()].
+*/
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
+
+/*
+** CAPI3REF: Reset All Bindings On A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
+** the [sqlite3_bind_blob | bindings] on a [prepared statement].
+** ^Use this routine to reset all host parameters to NULL.
+*/
+SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number Of Columns In A Result Set
+** METHOD: sqlite3_stmt
+**
+** ^Return the number of columns in the result set returned by the
+** [prepared statement]. ^If this routine returns 0, that means the
+** [prepared statement] returns no data (for example an [UPDATE]).
+** ^However, just because this routine returns a positive number does not
+** mean that one or more rows of data will be returned.  ^A SELECT statement
+** will always have a positive sqlite3_column_count() but depending on the
+** WHERE clause constraints and the table content, it might return no rows.
+**
+** See also: [sqlite3_data_count()]
+*/
+SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Column Names In A Result Set
+** METHOD: sqlite3_stmt
+**
+** ^These routines return the name assigned to a particular column
+** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
+** interface returns a pointer to a zero-terminated UTF-8 string
+** and sqlite3_column_name16() returns a pointer to a zero-terminated
+** UTF-16 string.  ^The first parameter is the [prepared statement]
+** that implements the [SELECT] statement. ^The second parameter is the
+** column number.  ^The leftmost column is number 0.
+**
+** ^The returned string pointer is valid until either the [prepared statement]
+** is destroyed by [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the next call to
+** sqlite3_column_name() or sqlite3_column_name16() on the same column.
+**
+** ^If sqlite3_malloc() fails during the processing of either routine
+** (for example during a conversion from UTF-8 to UTF-16) then a
+** NULL pointer is returned.
+**
+** ^The name of a result column is the value of the "AS" clause for
+** that column, if there is an AS clause.  If there is no AS clause
+** then the name of the column is unspecified and may change from
+** one release of SQLite to the next.
+*/
+SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
+SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
+
+/*
+** CAPI3REF: Source Of Data In A Query Result
+** METHOD: sqlite3_stmt
+**
+** ^These routines provide a means to determine the database, table, and
+** table column that is the origin of a particular result column in
+** [SELECT] statement.
+** ^The name of the database or table or column can be returned as
+** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
+** the database name, the _table_ routines return the table name, and
+** the origin_ routines return the column name.
+** ^The returned string is valid until the [prepared statement] is destroyed
+** using [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the same information is requested
+** again in a different encoding.
+**
+** ^The names returned are the original un-aliased names of the
+** database, table, and column.
+**
+** ^The first argument to these interfaces is a [prepared statement].
+** ^These functions return information about the Nth result column returned by
+** the statement, where N is the second function argument.
+** ^The left-most column is column 0 for these routines.
+**
+** ^If the Nth column returned by the statement is an expression or
+** subquery and is not a column value, then all of these functions return
+** NULL.  ^These routines might also return NULL if a memory allocation error
+** occurs.  ^Otherwise, they return the name of the attached database, table,
+** or column that query result column was extracted from.
+**
+** ^As with all other SQLite APIs, those whose names end with "16" return
+** UTF-16 encoded strings and the other functions return UTF-8.
+**
+** ^These APIs are only available if the library was compiled with the
+** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
+**
+** If two or more threads call one or more
+** [sqlite3_column_database_name | column metadata interfaces]
+** for the same [prepared statement] and result column
+** at the same time then the results are undefined.
+*/
+SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
+
+/*
+** CAPI3REF: Declared Datatype Of A Query Result
+** METHOD: sqlite3_stmt
+**
+** ^(The first parameter is a [prepared statement].
+** If this statement is a [SELECT] statement and the Nth column of the
+** returned result set of that [SELECT] is a table column (not an
+** expression or subquery) then the declared type of the table
+** column is returned.)^  ^If the Nth column of the result set is an
+** expression or subquery, then a NULL pointer is returned.
+** ^The returned string is always UTF-8 encoded.
+**
+** ^(For example, given the database schema:
+**
+** CREATE TABLE t1(c1 VARIANT);
+**
+** and the following statement to be compiled:
+**
+** SELECT c1 + 1, c1 FROM t1;
+**
+** this routine would return the string "VARIANT" for the second result
+** column (i==1), and a NULL pointer for the first result column (i==0).)^
+**
+** ^SQLite uses dynamic run-time typing.  ^So just because a column
+** is declared to contain a particular type does not mean that the
+** data stored in that column is of the declared type.  SQLite is
+** strongly typed, but the typing is dynamic not static.  ^Type
+** is associated with individual values, not with the containers
+** used to hold those values.
+*/
+SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
+
+/*
+** CAPI3REF: Evaluate An SQL Statement
+** METHOD: sqlite3_stmt
+**
+** After a [prepared statement] has been prepared using any of
+** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
+** or [sqlite3_prepare16_v3()] or one of the legacy
+** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
+** must be called one or more times to evaluate the statement.
+**
+** The details of the behavior of the sqlite3_step() interface depend
+** on whether the statement was prepared using the newer "vX" interfaces
+** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
+** [sqlite3_prepare16_v2()] or the older legacy
+** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
+** new "vX" interface is recommended for new applications but the legacy
+** interface will continue to be supported.
+**
+** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
+** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
+** ^With the "v2" interface, any of the other [result codes] or
+** [extended result codes] might be returned as well.
+**
+** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
+** database locks it needs to do its job.  ^If the statement is a [COMMIT]
+** or occurs outside of an explicit transaction, then you can retry the
+** statement.  If the statement is not a [COMMIT] and occurs within an
+** explicit transaction then you should rollback the transaction before
+** continuing.
+**
+** ^[SQLITE_DONE] means that the statement has finished executing
+** successfully.  sqlite3_step() should not be called again on this virtual
+** machine without first calling [sqlite3_reset()] to reset the virtual
+** machine back to its initial state.
+**
+** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
+** is returned each time a new row of data is ready for processing by the
+** caller. The values may be accessed using the [column access functions].
+** sqlite3_step() is called again to retrieve the next row of data.
+**
+** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
+** violation) has occurred.  sqlite3_step() should not be called again on
+** the VM. More information may be found by calling [sqlite3_errmsg()].
+** ^With the legacy interface, a more specific error code (for example,
+** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
+** can be obtained by calling [sqlite3_reset()] on the
+** [prepared statement].  ^In the "v2" interface,
+** the more specific error code is returned directly by sqlite3_step().
+**
+** [SQLITE_MISUSE] means that the this routine was called inappropriately.
+** Perhaps it was called on a [prepared statement] that has
+** already been [sqlite3_finalize | finalized] or on one that had
+** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
+** be the case that the same database connection is being used by two or
+** more threads at the same moment in time.
+**
+** For all versions of SQLite up to and including 3.6.23.1, a call to
+** [sqlite3_reset()] was required after sqlite3_step() returned anything
+** other than [SQLITE_ROW] before any subsequent invocation of
+** sqlite3_step().  Failure to reset the prepared statement using
+** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
+** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
+** sqlite3_step() began
+** calling [sqlite3_reset()] automatically in this circumstance rather
+** than returning [SQLITE_MISUSE].  This is not considered a compatibility
+** break because any application that ever receives an SQLITE_MISUSE error
+** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
+** can be used to restore the legacy behavior.
+**
+** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
+** API always returns a generic error code, [SQLITE_ERROR], following any
+** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
+** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
+** specific [error codes] that better describes the error.
+** We admit that this is a goofy design.  The problem has been fixed
+** with the "v2" interface.  If you prepare all of your SQL statements
+** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
+** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
+** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
+** then the more specific [error codes] are returned directly
+** by sqlite3_step().  The use of the "vX" interfaces is recommended.
+*/
+SQLITE_API int sqlite3_step(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number of columns in a result set
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_data_count(P) interface returns the number of columns in the
+** current row of the result set of [prepared statement] P.
+** ^If prepared statement P does not have results ready to return
+** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
+** interfaces) then sqlite3_data_count(P) returns 0.
+** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
+** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
+** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
+** will return non-zero if previous call to [sqlite3_step](P) returned
+** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
+** where it always returns zero since each step of that multi-step
+** pragma returns 0 columns of data.
+**
+** See also: [sqlite3_column_count()]
+*/
+SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Fundamental Datatypes
+** KEYWORDS: SQLITE_TEXT
+**
+** ^(Every value in SQLite has one of five fundamental datatypes:
+**
+** <ul>
+** <li> 64-bit signed integer
+** <li> 64-bit IEEE floating point number
+** <li> string
+** <li> BLOB
+** <li> NULL
+** </ul>)^
+**
+** These constants are codes for each of those types.
+**
+** Note that the SQLITE_TEXT constant was also used in SQLite version 2
+** for a completely different meaning.  Software that links against both
+** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
+** SQLITE_TEXT.
+*/
+#define SQLITE_INTEGER  1
+#define SQLITE_FLOAT    2
+#define SQLITE_BLOB     4
+#define SQLITE_NULL     5
+#ifdef SQLITE_TEXT
+# undef SQLITE_TEXT
+#else
+# define SQLITE_TEXT     3
+#endif
+#define SQLITE3_TEXT     3
+
+/*
+** CAPI3REF: Result Values From A Query
+** KEYWORDS: {column access functions}
+** METHOD: sqlite3_stmt
+**
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result
+** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result
+** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result
+** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result
+** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result
+** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result
+** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an
+** [sqlite3_value|unprotected sqlite3_value] object.
+** <tr><td> <td> <td> 
+** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT result in bytes
+** <tr><td><b>sqlite3_column_bytes16  </b>
+** <td>→  <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_column_type</b><td>→<td>Default
+** datatype of the result
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
+** ^These routines return information about a single column of the current
+** result row of a query.  ^In every case the first argument is a pointer
+** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
+** that was returned from [sqlite3_prepare_v2()] or one of its variants)
+** and the second argument is the index of the column for which information
+** should be returned. ^The leftmost column of the result set has the index 0.
+** ^The number of columns in the result can be determined using
+** [sqlite3_column_count()].
+**
+** If the SQL statement does not currently point to a valid row, or if the
+** column index is out of range, the result is undefined.
+** These routines may only be called when the most recent call to
+** [sqlite3_step()] has returned [SQLITE_ROW] and neither
+** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
+** If any of these routines are called after [sqlite3_reset()] or
+** [sqlite3_finalize()] or after [sqlite3_step()] has returned
+** something other than [SQLITE_ROW], the results are undefined.
+** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
+** are called from a different thread while any of these routines
+** are pending, then the results are undefined.
+**
+** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
+** each return the value of a result column in a specific data format.  If
+** the result column is not initially in the requested format (for example,
+** if the query returns an integer but the sqlite3_column_text() interface
+** is used to extract the value) then an automatic type conversion is performed.
+**
+** ^The sqlite3_column_type() routine returns the
+** [SQLITE_INTEGER | datatype code] for the initial data type
+** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
+** The return value of sqlite3_column_type() can be used to decide which
+** of the first six interface should be used to extract the column value.
+** The value returned by sqlite3_column_type() is only meaningful if no
+** automatic type conversions have occurred for the value in question.
+** After a type conversion, the result of calling sqlite3_column_type()
+** is undefined, though harmless.  Future
+** versions of SQLite may change the behavior of sqlite3_column_type()
+** following a type conversion.
+**
+** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
+** or sqlite3_column_bytes16() interfaces can be used to determine the size
+** of that BLOB or string.
+**
+** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
+** the string to UTF-8 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
+**
+** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
+** the string to UTF-16 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes16() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
+**
+** ^The values returned by [sqlite3_column_bytes()] and
+** [sqlite3_column_bytes16()] do not include the zero terminators at the end
+** of the string.  ^For clarity: the values returned by
+** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
+** bytes in the string, not the number of characters.
+**
+** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
+** even empty strings, are always zero-terminated.  ^The return
+** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
+**
+** ^Strings returned by sqlite3_column_text16() always have the endianness
+** which is native to the platform, regardless of the text encoding set
+** for the database.
+**
+** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
+** [unprotected sqlite3_value] object.  In a multithreaded environment,
+** an unprotected sqlite3_value object may only be used safely with
+** [sqlite3_bind_value()] and [sqlite3_result_value()].
+** If the [unprotected sqlite3_value] object returned by
+** [sqlite3_column_value()] is used in any other way, including calls
+** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
+** or [sqlite3_value_bytes()], the behavior is not threadsafe.
+** Hence, the sqlite3_column_value() interface
+** is normally only useful within the implementation of
+** [application-defined SQL functions] or [virtual tables], not within
+** top-level application code.
+**
+** These routines may attempt to convert the datatype of the result.
+** ^For example, if the internal representation is FLOAT and a text result
+** is requested, [sqlite3_snprintf()] is used internally to perform the
+** conversion automatically.  ^(The following table details the conversions
+** that are applied:
+**
+** <blockquote>
+** <table border="1">
+** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
+**
+** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
+** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
+** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
+** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
+** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
+** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
+** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
+** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
+** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
+** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
+** <tr><td>  TEXT    <td>   BLOB    <td> No change
+** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
+** <tr><td>  BLOB    <td>   TEXT    <td> [CAST] to TEXT, ensure zero terminator
+** </table>
+** </blockquote>)^
+**
+** Note that when type conversions occur, pointers returned by prior
+** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
+** sqlite3_column_text16() may be invalidated.
+** Type conversions and pointer invalidations might occur
+** in the following cases:
+**
+** <ul>
+** <li> The initial content is a BLOB and sqlite3_column_text() or
+**      sqlite3_column_text16() is called.  A zero-terminator might
+**      need to be added to the string.</li>
+** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
+**      sqlite3_column_text16() is called.  The content must be converted
+**      to UTF-16.</li>
+** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
+**      sqlite3_column_text() is called.  The content must be converted
+**      to UTF-8.</li>
+** </ul>
+**
+** ^Conversions between UTF-16be and UTF-16le are always done in place and do
+** not invalidate a prior pointer, though of course the content of the buffer
+** that the prior pointer references will have been modified.  Other kinds
+** of conversion are done in place when it is possible, but sometimes they
+** are not possible and in those cases prior pointers are invalidated.
+**
+** The safest policy is to invoke these routines
+** in one of the following ways:
+**
+** <ul>
+**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
+** </ul>
+**
+** In other words, you should call sqlite3_column_text(),
+** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
+** into the desired format, then invoke sqlite3_column_bytes() or
+** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
+** to sqlite3_column_text() or sqlite3_column_blob() with calls to
+** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
+** with calls to sqlite3_column_bytes().
+**
+** ^The pointers returned are valid until a type conversion occurs as
+** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
+** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
+** and BLOBs is freed automatically.  Do not pass the pointers returned
+** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
+** [sqlite3_free()].
+**
+** As long as the input parameters are correct, these routines will only
+** fail if an out-of-memory error occurs during a format conversion.
+** Only the following subset of interfaces are subject to out-of-memory
+** errors:
+**
+** <ul>
+** <li> sqlite3_column_blob()
+** <li> sqlite3_column_text()
+** <li> sqlite3_column_text16()
+** <li> sqlite3_column_bytes()
+** <li> sqlite3_column_bytes16()
+** </ul>
+**
+** If an out-of-memory error occurs, then the return value from these
+** routines is the same as if the column had contained an SQL NULL value.
+** Valid SQL NULL returns can be distinguished from out-of-memory errors
+** by invoking the [sqlite3_errcode()] immediately after the suspect
+** return value is obtained and before any
+** other SQLite interface is called on the same [database connection].
+*/
+SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
+SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
+SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
+SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
+
+/*
+** CAPI3REF: Destroy A Prepared Statement Object
+** DESTRUCTOR: sqlite3_stmt
+**
+** ^The sqlite3_finalize() function is called to delete a [prepared statement].
+** ^If the most recent evaluation of the statement encountered no errors
+** or if the statement is never been evaluated, then sqlite3_finalize() returns
+** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
+** sqlite3_finalize(S) returns the appropriate [error code] or
+** [extended error code].
+**
+** ^The sqlite3_finalize(S) routine can be called at any point during
+** the life cycle of [prepared statement] S:
+** before statement S is ever evaluated, after
+** one or more calls to [sqlite3_reset()], or after any call
+** to [sqlite3_step()] regardless of whether or not the statement has
+** completed execution.
+**
+** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
+**
+** The application must finalize every [prepared statement] in order to avoid
+** resource leaks.  It is a grievous error for the application to try to use
+** a prepared statement after it has been finalized.  Any use of a prepared
+** statement after it has been finalized can result in undefined and
+** undesirable behavior such as segfaults and heap corruption.
+*/
+SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Reset A Prepared Statement Object
+** METHOD: sqlite3_stmt
+**
+** The sqlite3_reset() function is called to reset a [prepared statement]
+** object back to its initial state, ready to be re-executed.
+** ^Any SQL statement variables that had values bound to them using
+** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
+** Use [sqlite3_clear_bindings()] to reset the bindings.
+**
+** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
+** back to the beginning of its program.
+**
+** ^The return code from [sqlite3_reset(S)] indicates whether or not
+** the previous evaluation of prepared statement S completed successfully.
+** ^If [sqlite3_step(S)] has never before been called on S or if
+** [sqlite3_step(S)] has not been called since the previous call
+** to [sqlite3_reset(S)], then [sqlite3_reset(S)] will return
+** [SQLITE_OK].
+**
+** ^If the most recent call to [sqlite3_step(S)] for the
+** [prepared statement] S indicated an error, then
+** [sqlite3_reset(S)] returns an appropriate [error code].
+** ^The [sqlite3_reset(S)] interface might also return an [error code]
+** if there were no prior errors but the process of resetting
+** the prepared statement caused a new error. ^For example, if an
+** [INSERT] statement with a [RETURNING] clause is only stepped one time,
+** that one call to [sqlite3_step(S)] might return SQLITE_ROW but
+** the overall statement might still fail and the [sqlite3_reset(S)] call
+** might return SQLITE_BUSY if locking constraints prevent the
+** database change from committing.  Therefore, it is important that
+** applications check the return code from [sqlite3_reset(S)] even if
+** no prior call to [sqlite3_step(S)] indicated a problem.
+**
+** ^The [sqlite3_reset(S)] interface does not change the values
+** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
+*/
+SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
+
+
+/*
+** CAPI3REF: Create Or Redefine SQL Functions
+** KEYWORDS: {function creation routines}
+** METHOD: sqlite3
+**
+** ^These functions (collectively known as "function creation routines")
+** are used to add SQL functions or aggregates or to redefine the behavior
+** of existing SQL functions or aggregates. The only differences between
+** the three "sqlite3_create_function*" routines are the text encoding
+** expected for the second parameter (the name of the function being
+** created) and the presence or absence of a destructor callback for
+** the application data pointer. Function sqlite3_create_window_function()
+** is similar, but allows the user to supply the extra callback functions
+** needed by [aggregate window functions].
+**
+** ^The first parameter is the [database connection] to which the SQL
+** function is to be added.  ^If an application uses more than one database
+** connection then application-defined SQL functions must be added
+** to each database connection separately.
+**
+** ^The second parameter is the name of the SQL function to be created or
+** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
+** representation, exclusive of the zero-terminator.  ^Note that the name
+** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
+** ^Any attempt to create a function with a longer name
+** will result in [SQLITE_MISUSE] being returned.
+**
+** ^The third parameter (nArg)
+** is the number of arguments that the SQL function or
+** aggregate takes. ^If this parameter is -1, then the SQL function or
+** aggregate may take any number of arguments between 0 and the limit
+** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
+** parameter is less than -1 or greater than 127 then the behavior is
+** undefined.
+**
+** ^The fourth parameter, eTextRep, specifies what
+** [SQLITE_UTF8 | text encoding] this SQL function prefers for
+** its parameters.  The application should set this parameter to
+** [SQLITE_UTF16LE] if the function implementation invokes
+** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
+** implementation invokes [sqlite3_value_text16be()] on an input, or
+** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
+** otherwise.  ^The same SQL function may be registered multiple times using
+** different preferred text encodings, with different implementations for
+** each encoding.
+** ^When multiple implementations of the same function are available, SQLite
+** will pick the one that involves the least amount of data conversion.
+**
+** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
+** to signal that the function will always return the same result given
+** the same inputs within a single SQL statement.  Most SQL functions are
+** deterministic.  The built-in [random()] SQL function is an example of a
+** function that is not deterministic.  The SQLite query planner is able to
+** perform additional optimizations on deterministic functions, so use
+** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
+**
+** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
+** flag, which if present prevents the function from being invoked from
+** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
+** index expressions, or the WHERE clause of partial indexes.
+**
+** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
+** all application-defined SQL functions that do not need to be
+** used inside of triggers, view, CHECK constraints, or other elements of
+** the database schema.  This flags is especially recommended for SQL
+** functions that have side effects or reveal internal application state.
+** Without this flag, an attacker might be able to modify the schema of
+** a database file to include invocations of the function with parameters
+** chosen by the attacker, which the application will then execute when
+** the database file is opened and read.
+**
+** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
+** function can gain access to this pointer using [sqlite3_user_data()].)^
+**
+** ^The sixth, seventh and eighth parameters passed to the three
+** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
+** pointers to C-language functions that implement the SQL function or
+** aggregate. ^A scalar SQL function requires an implementation of the xFunc
+** callback only; NULL pointers must be passed as the xStep and xFinal
+** parameters. ^An aggregate SQL function requires an implementation of xStep
+** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
+** SQL function or aggregate, pass NULL pointers for all three function
+** callbacks.
+**
+** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
+** and xInverse) passed to sqlite3_create_window_function are pointers to
+** C-language callbacks that implement the new function. xStep and xFinal
+** must both be non-NULL. xValue and xInverse may either both be NULL, in
+** which case a regular aggregate function is created, or must both be
+** non-NULL, in which case the new function may be used as either an aggregate
+** or aggregate window function. More details regarding the implementation
+** of aggregate window functions are
+** [user-defined window functions|available here].
+**
+** ^(If the final parameter to sqlite3_create_function_v2() or
+** sqlite3_create_window_function() is not NULL, then it is destructor for
+** the application data pointer. The destructor is invoked when the function
+** is deleted, either by being overloaded or when the database connection
+** closes.)^ ^The destructor is also invoked if the call to
+** sqlite3_create_function_v2() fails.  ^When the destructor callback is
+** invoked, it is passed a single argument which is a copy of the application
+** data pointer which was the fifth parameter to sqlite3_create_function_v2().
+**
+** ^It is permitted to register multiple implementations of the same
+** functions with the same name but with either differing numbers of
+** arguments or differing preferred text encodings.  ^SQLite will use
+** the implementation that most closely matches the way in which the
+** SQL function is used.  ^A function implementation with a non-negative
+** nArg parameter is a better match than a function implementation with
+** a negative nArg.  ^A function where the preferred text encoding
+** matches the database encoding is a better
+** match than a function where the encoding is different.
+** ^A function where the encoding difference is between UTF16le and UTF16be
+** is a closer match than a function where the encoding difference is
+** between UTF8 and UTF16.
+**
+** ^Built-in functions may be overloaded by new application-defined functions.
+**
+** ^An application-defined function is permitted to call other
+** SQLite interfaces.  However, such calls must not
+** close the database connection nor finalize or reset the prepared
+** statement in which the function is running.
+*/
+SQLITE_API int sqlite3_create_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+SQLITE_API int sqlite3_create_function16(
+  sqlite3 *db,
+  const void *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+SQLITE_API int sqlite3_create_function_v2(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void(*xDestroy)(void*)
+);
+SQLITE_API int sqlite3_create_window_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
+  void(*xDestroy)(void*)
+);
+
+/*
+** CAPI3REF: Text Encodings
+**
+** These constant define integer codes that represent the various
+** text encodings supported by SQLite.
+*/
+#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
+#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
+#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
+#define SQLITE_UTF16          4    /* Use native byte order */
+#define SQLITE_ANY            5    /* Deprecated */
+#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
+
+/*
+** CAPI3REF: Function Flags
+**
+** These constants may be ORed together with the
+** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
+** to [sqlite3_create_function()], [sqlite3_create_function16()], or
+** [sqlite3_create_function_v2()].
+**
+** <dl>
+** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
+** The SQLITE_DETERMINISTIC flag means that the new function always gives
+** the same output when the input parameters are the same.
+** The [abs|abs() function] is deterministic, for example, but
+** [randomblob|randomblob()] is not.  Functions must
+** be deterministic in order to be used in certain contexts such as
+** with the WHERE clause of [partial indexes] or in [generated columns].
+** SQLite might also optimize deterministic functions by factoring them
+** out of inner loops.
+** </dd>
+**
+** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
+** The SQLITE_DIRECTONLY flag means that the function may only be invoked
+** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
+** schema structures such as [CHECK constraints], [DEFAULT clauses],
+** [expression indexes], [partial indexes], or [generated columns].
+** <p>
+** The SQLITE_DIRECTONLY flag is recommended for any
+** [application-defined SQL function]
+** that has side-effects or that could potentially leak sensitive information.
+** This will prevent attacks in which an application is tricked
+** into using a database file that has had its schema surreptitiously
+** modified to invoke the application-defined function in ways that are
+** harmful.
+** <p>
+** Some people say it is good practice to set SQLITE_DIRECTONLY on all
+** [application-defined SQL functions], regardless of whether or not they
+** are security sensitive, as doing so prevents those functions from being used
+** inside of the database schema, and thus ensures that the database
+** can be inspected and modified using generic tools (such as the [CLI])
+** that do not have access to the application-defined functions.
+** </dd>
+**
+** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
+** The SQLITE_INNOCUOUS flag means that the function is unlikely
+** to cause problems even if misused.  An innocuous function should have
+** no side effects and should not depend on any values other than its
+** input parameters. The [abs|abs() function] is an example of an
+** innocuous function.
+** The [load_extension() SQL function] is not innocuous because of its
+** side effects.
+** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
+** exactly the same.  The [random|random() function] is an example of a
+** function that is innocuous but not deterministic.
+** <p>Some heightened security settings
+** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
+** disable the use of SQL functions inside views and triggers and in
+** schema structures such as [CHECK constraints], [DEFAULT clauses],
+** [expression indexes], [partial indexes], and [generated columns] unless
+** the function is tagged with SQLITE_INNOCUOUS.  Most built-in functions
+** are innocuous.  Developers are advised to avoid using the
+** SQLITE_INNOCUOUS flag for application-defined functions unless the
+** function has been carefully audited and found to be free of potentially
+** security-adverse side-effects and information-leaks.
+** </dd>
+**
+** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
+** The SQLITE_SUBTYPE flag indicates to SQLite that a function might call
+** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
+** This flag instructs SQLite to omit some corner-case optimizations that
+** might disrupt the operation of the [sqlite3_value_subtype()] function,
+** causing it to return zero rather than the correct subtype().
+** All SQL functions that invoke [sqlite3_value_subtype()] should have this
+** property.  If the SQLITE_SUBTYPE property is omitted, then the return
+** value from [sqlite3_value_subtype()] might sometimes be zero even though
+** a non-zero subtype was specified by the function argument expression.
+**
+** [[SQLITE_RESULT_SUBTYPE]] <dt>SQLITE_RESULT_SUBTYPE</dt><dd>
+** The SQLITE_RESULT_SUBTYPE flag indicates to SQLite that a function might call
+** [sqlite3_result_subtype()] to cause a sub-type to be associated with its
+** result.
+** Every function that invokes [sqlite3_result_subtype()] should have this
+** property.  If it does not, then the call to [sqlite3_result_subtype()]
+** might become a no-op if the function is used as term in an
+** [expression index].  On the other hand, SQL functions that never invoke
+** [sqlite3_result_subtype()] should avoid setting this property, as the
+** purpose of this property is to disable certain optimizations that are
+** incompatible with subtypes.
+**
+** [[SQLITE_SELFORDER1]] <dt>SQLITE_SELFORDER1</dt><dd>
+** The SQLITE_SELFORDER1 flag indicates that the function is an aggregate
+** that internally orders the values provided to the first argument.  The
+** ordered-set aggregate SQL notation with a single ORDER BY term can be
+** used to invoke this function.  If the ordered-set aggregate notation is
+** used on a function that lacks this flag, then an error is raised. Note
+** that the ordered-set aggregate syntax is only available if SQLite is
+** built using the -DSQLITE_ENABLE_ORDERED_SET_AGGREGATES compile-time option.
+** </dd>
+** </dl>
+*/
+#define SQLITE_DETERMINISTIC    0x000000800
+#define SQLITE_DIRECTONLY       0x000080000
+#define SQLITE_SUBTYPE          0x000100000
+#define SQLITE_INNOCUOUS        0x000200000
+#define SQLITE_RESULT_SUBTYPE   0x001000000
+#define SQLITE_SELFORDER1       0x002000000
+
+/*
+** CAPI3REF: Deprecated Functions
+** DEPRECATED
+**
+** These functions are [deprecated].  In order to maintain
+** backwards compatibility with older code, these functions continue
+** to be supported.  However, new applications should avoid
+** the use of these functions.  To encourage programmers to avoid
+** these functions, we will not explain what they do.
+*/
+#ifndef SQLITE_OMIT_DEPRECATED
+SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
+SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
+                      void*,sqlite3_int64);
+#endif
+
+/*
+** CAPI3REF: Obtaining SQL Values
+** METHOD: sqlite3_value
+**
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value
+** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value
+** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value
+** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value
+** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value
+** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value
+** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in
+** the native byteorder
+** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value
+** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value
+** <tr><td> <td> <td> 
+** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT in bytes
+** <tr><td><b>sqlite3_value_bytes16  </b>
+** <td>→  <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_value_type</b><td>→<td>Default
+** datatype of the value
+** <tr><td><b>sqlite3_value_numeric_type  </b>
+** <td>→  <td>Best numeric datatype of the value
+** <tr><td><b>sqlite3_value_nochange  </b>
+** <td>→  <td>True if the column is unchanged in an UPDATE
+** against a virtual table.
+** <tr><td><b>sqlite3_value_frombind  </b>
+** <td>→  <td>True if value originated from a [bound parameter]
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
+** These routines extract type, size, and content information from
+** [protected sqlite3_value] objects.  Protected sqlite3_value objects
+** are used to pass parameter information into the functions that
+** implement [application-defined SQL functions] and [virtual tables].
+**
+** These routines work only with [protected sqlite3_value] objects.
+** Any attempt to use these routines on an [unprotected sqlite3_value]
+** is not threadsafe.
+**
+** ^These routines work just like the corresponding [column access functions]
+** except that these routines take a single [protected sqlite3_value] object
+** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
+**
+** ^The sqlite3_value_text16() interface extracts a UTF-16 string
+** in the native byte-order of the host machine.  ^The
+** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
+** extract UTF-16 strings as big-endian and little-endian respectively.
+**
+** ^If [sqlite3_value] object V was initialized
+** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
+** and if X and Y are strings that compare equal according to strcmp(X,Y),
+** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
+** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
+** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
+**
+** ^(The sqlite3_value_type(V) interface returns the
+** [SQLITE_INTEGER | datatype code] for the initial datatype of the
+** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
+** Other interfaces might change the datatype for an sqlite3_value object.
+** For example, if the datatype is initially SQLITE_INTEGER and
+** sqlite3_value_text(V) is called to extract a text value for that
+** integer, then subsequent calls to sqlite3_value_type(V) might return
+** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
+** occurs is undefined and may change from one release of SQLite to the next.
+**
+** ^(The sqlite3_value_numeric_type() interface attempts to apply
+** numeric affinity to the value.  This means that an attempt is
+** made to convert the value to an integer or floating point.  If
+** such a conversion is possible without loss of information (in other
+** words, if the value is a string that looks like a number)
+** then the conversion is performed.  Otherwise no conversion occurs.
+** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
+**
+** ^Within the [xUpdate] method of a [virtual table], the
+** sqlite3_value_nochange(X) interface returns true if and only if
+** the column corresponding to X is unchanged by the UPDATE operation
+** that the xUpdate method call was invoked to implement and if
+** and the prior [xColumn] method call that was invoked to extracted
+** the value for that column returned without setting a result (probably
+** because it queried [sqlite3_vtab_nochange()] and found that the column
+** was unchanging).  ^Within an [xUpdate] method, any value for which
+** sqlite3_value_nochange(X) is true will in all other respects appear
+** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
+** than within an [xUpdate] method call for an UPDATE statement, then
+** the return value is arbitrary and meaningless.
+**
+** ^The sqlite3_value_frombind(X) interface returns non-zero if the
+** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
+** interfaces.  ^If X comes from an SQL literal value, or a table column,
+** or an expression, then sqlite3_value_frombind(X) returns zero.
+**
+** Please pay particular attention to the fact that the pointer returned
+** from [sqlite3_value_blob()], [sqlite3_value_text()], or
+** [sqlite3_value_text16()] can be invalidated by a subsequent call to
+** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
+** or [sqlite3_value_text16()].
+**
+** These routines must be called from the same thread as
+** the SQL function that supplied the [sqlite3_value*] parameters.
+**
+** As long as the input parameter is correct, these routines can only
+** fail if an out-of-memory error occurs during a format conversion.
+** Only the following subset of interfaces are subject to out-of-memory
+** errors:
+**
+** <ul>
+** <li> sqlite3_value_blob()
+** <li> sqlite3_value_text()
+** <li> sqlite3_value_text16()
+** <li> sqlite3_value_text16le()
+** <li> sqlite3_value_text16be()
+** <li> sqlite3_value_bytes()
+** <li> sqlite3_value_bytes16()
+** </ul>
+**
+** If an out-of-memory error occurs, then the return value from these
+** routines is the same as if the column had contained an SQL NULL value.
+** Valid SQL NULL returns can be distinguished from out-of-memory errors
+** by invoking the [sqlite3_errcode()] immediately after the suspect
+** return value is obtained and before any
+** other SQLite interface is called on the same [database connection].
+*/
+SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
+SQLITE_API double sqlite3_value_double(sqlite3_value*);
+SQLITE_API int sqlite3_value_int(sqlite3_value*);
+SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
+SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
+SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
+SQLITE_API int sqlite3_value_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
+SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
+
+/*
+** CAPI3REF: Report the internal text encoding state of an sqlite3_value object
+** METHOD: sqlite3_value
+**
+** ^(The sqlite3_value_encoding(X) interface returns one of [SQLITE_UTF8],
+** [SQLITE_UTF16BE], or [SQLITE_UTF16LE] according to the current text encoding
+** of the value X, assuming that X has type TEXT.)^  If sqlite3_value_type(X)
+** returns something other than SQLITE_TEXT, then the return value from
+** sqlite3_value_encoding(X) is meaningless.  ^Calls to
+** [sqlite3_value_text(X)], [sqlite3_value_text16(X)], [sqlite3_value_text16be(X)],
+** [sqlite3_value_text16le(X)], [sqlite3_value_bytes(X)], or
+** [sqlite3_value_bytes16(X)] might change the encoding of the value X and
+** thus change the return from subsequent calls to sqlite3_value_encoding(X).
+**
+** This routine is intended for used by applications that test and validate
+** the SQLite implementation.  This routine is inquiring about the opaque
+** internal state of an [sqlite3_value] object.  Ordinary applications should
+** not need to know what the internal state of an sqlite3_value object is and
+** hence should not need to use this interface.
+*/
+SQLITE_API int sqlite3_value_encoding(sqlite3_value*);
+
+/*
+** CAPI3REF: Finding The Subtype Of SQL Values
+** METHOD: sqlite3_value
+**
+** The sqlite3_value_subtype(V) function returns the subtype for
+** an [application-defined SQL function] argument V.  The subtype
+** information can be used to pass a limited amount of context from
+** one SQL function to another.  Use the [sqlite3_result_subtype()]
+** routine to set the subtype for the return value of an SQL function.
+**
+** Every [application-defined SQL function] that invokes this interface
+** should include the [SQLITE_SUBTYPE] property in the text
+** encoding argument when the function is [sqlite3_create_function|registered].
+** If the [SQLITE_SUBTYPE] property is omitted, then sqlite3_value_subtype()
+** might return zero instead of the upstream subtype in some corner cases.
+*/
+SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
+
+/*
+** CAPI3REF: Copy And Free SQL Values
+** METHOD: sqlite3_value
+**
+** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
+** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
+** is a [protected sqlite3_value] object even if the input is not.
+** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
+** memory allocation fails. ^If V is a [pointer value], then the result
+** of sqlite3_value_dup(V) is a NULL value.
+**
+** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
+** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
+** then sqlite3_value_free(V) is a harmless no-op.
+*/
+SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
+SQLITE_API void sqlite3_value_free(sqlite3_value*);
+
+/*
+** CAPI3REF: Obtain Aggregate Function Context
+** METHOD: sqlite3_context
+**
+** Implementations of aggregate SQL functions use this
+** routine to allocate memory for storing their state.
+**
+** ^The first time the sqlite3_aggregate_context(C,N) routine is called
+** for a particular aggregate function, SQLite allocates
+** N bytes of memory, zeroes out that memory, and returns a pointer
+** to the new memory. ^On second and subsequent calls to
+** sqlite3_aggregate_context() for the same aggregate function instance,
+** the same buffer is returned.  Sqlite3_aggregate_context() is normally
+** called once for each invocation of the xStep callback and then one
+** last time when the xFinal callback is invoked.  ^(When no rows match
+** an aggregate query, the xStep() callback of the aggregate function
+** implementation is never called and xFinal() is called exactly once.
+** In those cases, sqlite3_aggregate_context() might be called for the
+** first time from within xFinal().)^
+**
+** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
+** when first called if N is less than or equal to zero or if a memory
+** allocation error occurs.
+**
+** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
+** determined by the N parameter on first successful call.  Changing the
+** value of N in any subsequent call to sqlite3_aggregate_context() within
+** the same aggregate function instance will not resize the memory
+** allocation.)^  Within the xFinal callback, it is customary to set
+** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
+** pointless memory allocations occur.
+**
+** ^SQLite automatically frees the memory allocated by
+** sqlite3_aggregate_context() when the aggregate query concludes.
+**
+** The first parameter must be a copy of the
+** [sqlite3_context | SQL function context] that is the first parameter
+** to the xStep or xFinal callback routine that implements the aggregate
+** function.
+**
+** This routine must be called from the same thread in which
+** the aggregate SQL function is running.
+*/
+SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
+
+/*
+** CAPI3REF: User Data For Functions
+** METHOD: sqlite3_context
+**
+** ^The sqlite3_user_data() interface returns a copy of
+** the pointer that was the pUserData parameter (the 5th parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+**
+** This routine must be called from the same thread in which
+** the application-defined function is running.
+*/
+SQLITE_API void *sqlite3_user_data(sqlite3_context*);
+
+/*
+** CAPI3REF: Database Connection For Functions
+** METHOD: sqlite3_context
+**
+** ^The sqlite3_context_db_handle() interface returns a copy of
+** the pointer to the [database connection] (the 1st parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+*/
+SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
+
+/*
+** CAPI3REF: Function Auxiliary Data
+** METHOD: sqlite3_context
+**
+** These functions may be used by (non-aggregate) SQL functions to
+** associate auxiliary data with argument values. If the same argument
+** value is passed to multiple invocations of the same SQL function during
+** query execution, under some circumstances the associated auxiliary data
+** might be preserved.  An example of where this might be useful is in a
+** regular-expression matching function. The compiled version of the regular
+** expression can be stored as auxiliary data associated with the pattern string.
+** Then as long as the pattern string remains the same,
+** the compiled regular expression can be reused on multiple
+** invocations of the same function.
+**
+** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the auxiliary data
+** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
+** value to the application-defined function.  ^N is zero for the left-most
+** function argument.  ^If there is no auxiliary data
+** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
+** returns a NULL pointer.
+**
+** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as auxiliary data for the
+** N-th argument of the application-defined function.  ^Subsequent
+** calls to sqlite3_get_auxdata(C,N) return P from the most recent
+** sqlite3_set_auxdata(C,N,P,X) call if the auxiliary data is still valid or
+** NULL if the auxiliary data has been discarded.
+** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
+** SQLite will invoke the destructor function X with parameter P exactly
+** once, when the auxiliary data is discarded.
+** SQLite is free to discard the auxiliary data at any time, including: <ul>
+** <li> ^(when the corresponding function parameter changes)^, or
+** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
+**      SQL statement)^, or
+** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
+**       parameter)^, or
+** <li> ^(during the original sqlite3_set_auxdata() call when a memory
+**      allocation error occurs.)^
+** <li> ^(during the original sqlite3_set_auxdata() call if the function
+**      is evaluated during query planning instead of during query execution,
+**      as sometimes happens with [SQLITE_ENABLE_STAT4].)^ </ul>
+**
+** Note the last two bullets in particular.  The destructor X in
+** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
+** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
+** should be called near the end of the function implementation and the
+** function implementation should not make any use of P after
+** sqlite3_set_auxdata() has been called.  Furthermore, a call to
+** sqlite3_get_auxdata() that occurs immediately after a corresponding call
+** to sqlite3_set_auxdata() might still return NULL if an out-of-memory
+** condition occurred during the sqlite3_set_auxdata() call or if the
+** function is being evaluated during query planning rather than during
+** query execution.
+**
+** ^(In practice, auxiliary data is preserved between function calls for
+** function parameters that are compile-time constants, including literal
+** values and [parameters] and expressions composed from the same.)^
+**
+** The value of the N parameter to these interfaces should be non-negative.
+** Future enhancements may make use of negative N values to define new
+** kinds of function caching behavior.
+**
+** These routines must be called from the same thread in which
+** the SQL function is running.
+**
+** See also: [sqlite3_get_clientdata()] and [sqlite3_set_clientdata()].
+*/
+SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
+SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
+
+/*
+** CAPI3REF: Database Connection Client Data
+** METHOD: sqlite3
+**
+** These functions are used to associate one or more named pointers
+** with a [database connection].
+** A call to sqlite3_set_clientdata(D,N,P,X) causes the pointer P
+** to be attached to [database connection] D using name N.  Subsequent
+** calls to sqlite3_get_clientdata(D,N) will return a copy of pointer P
+** or a NULL pointer if there were no prior calls to
+** sqlite3_set_clientdata() with the same values of D and N.
+** Names are compared using strcmp() and are thus case sensitive.
+**
+** If P and X are both non-NULL, then the destructor X is invoked with
+** argument P on the first of the following occurrences:
+** <ul>
+** <li> An out-of-memory error occurs during the call to
+**      sqlite3_set_clientdata() which attempts to register pointer P.
+** <li> A subsequent call to sqlite3_set_clientdata(D,N,P,X) is made
+**      with the same D and N parameters.
+** <li> The database connection closes.  SQLite does not make any guarantees
+**      about the order in which destructors are called, only that all
+**      destructors will be called exactly once at some point during the
+**      database connection closing process.
+** </ul>
+**
+** SQLite does not do anything with client data other than invoke
+** destructors on the client data at the appropriate time.  The intended
+** use for client data is to provide a mechanism for wrapper libraries
+** to store additional information about an SQLite database connection.
+**
+** There is no limit (other than available memory) on the number of different
+** client data pointers (with different names) that can be attached to a
+** single database connection.  However, the implementation is optimized
+** for the case of having only one or two different client data names.
+** Applications and wrapper libraries are discouraged from using more than
+** one client data name each.
+**
+** There is no way to enumerate the client data pointers
+** associated with a database connection.  The N parameter can be thought
+** of as a secret key such that only code that knows the secret key is able
+** to access the associated data.
+**
+** Security Warning:  These interfaces should not be exposed in scripting
+** languages or in other circumstances where it might be possible for an
+** an attacker to invoke them.  Any agent that can invoke these interfaces
+** can probably also take control of the process.
+**
+** Database connection client data is only available for SQLite
+** version 3.44.0 ([dateof:3.44.0]) and later.
+**
+** See also: [sqlite3_set_auxdata()] and [sqlite3_get_auxdata()].
+*/
+SQLITE_API void *sqlite3_get_clientdata(sqlite3*,const char*);
+SQLITE_API int sqlite3_set_clientdata(sqlite3*, const char*, void*, void(*)(void*));
+
+/*
+** CAPI3REF: Constants Defining Special Destructor Behavior
+**
+** These are special values for the destructor that is passed in as the
+** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
+** argument is SQLITE_STATIC, it means that the content pointer is constant
+** and will never change.  It does not need to be destroyed.  ^The
+** SQLITE_TRANSIENT value means that the content will likely change in
+** the near future and that SQLite should make its own private copy of
+** the content before returning.
+**
+** The typedef is necessary to work around problems in certain
+** C++ compilers.
+*/
+typedef void (*sqlite3_destructor_type)(void*);
+#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
+#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
+
+/*
+** CAPI3REF: Setting The Result Of An SQL Function
+** METHOD: sqlite3_context
+**
+** These routines are used by the xFunc or xFinal callbacks that
+** implement SQL functions and aggregates.  See
+** [sqlite3_create_function()] and [sqlite3_create_function16()]
+** for additional information.
+**
+** These functions work very much like the [parameter binding] family of
+** functions used to bind values to host parameters in prepared statements.
+** Refer to the [SQL parameter] documentation for additional information.
+**
+** ^The sqlite3_result_blob() interface sets the result from
+** an application-defined function to be the BLOB whose content is pointed
+** to by the second parameter and which is N bytes long where N is the
+** third parameter.
+**
+** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
+** interfaces set the result of the application-defined function to be
+** a BLOB containing all zero bytes and N bytes in size.
+**
+** ^The sqlite3_result_double() interface sets the result from
+** an application-defined function to be a floating point value specified
+** by its 2nd argument.
+**
+** ^The sqlite3_result_error() and sqlite3_result_error16() functions
+** cause the implemented SQL function to throw an exception.
+** ^SQLite uses the string pointed to by the
+** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
+** as the text of an error message.  ^SQLite interprets the error
+** message string from sqlite3_result_error() as UTF-8. ^SQLite
+** interprets the string from sqlite3_result_error16() as UTF-16 using
+** the same [byte-order determination rules] as [sqlite3_bind_text16()].
+** ^If the third parameter to sqlite3_result_error()
+** or sqlite3_result_error16() is negative then SQLite takes as the error
+** message all text up through the first zero character.
+** ^If the third parameter to sqlite3_result_error() or
+** sqlite3_result_error16() is non-negative then SQLite takes that many
+** bytes (not characters) from the 2nd parameter as the error message.
+** ^The sqlite3_result_error() and sqlite3_result_error16()
+** routines make a private copy of the error message text before
+** they return.  Hence, the calling function can deallocate or
+** modify the text after they return without harm.
+** ^The sqlite3_result_error_code() function changes the error code
+** returned by SQLite as a result of an error in a function.  ^By default,
+** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
+** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
+**
+** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
+** error indicating that a string or BLOB is too long to represent.
+**
+** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
+** error indicating that a memory allocation failed.
+**
+** ^The sqlite3_result_int() interface sets the return value
+** of the application-defined function to be the 32-bit signed integer
+** value given in the 2nd argument.
+** ^The sqlite3_result_int64() interface sets the return value
+** of the application-defined function to be the 64-bit signed integer
+** value given in the 2nd argument.
+**
+** ^The sqlite3_result_null() interface sets the return value
+** of the application-defined function to be NULL.
+**
+** ^The sqlite3_result_text(), sqlite3_result_text16(),
+** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
+** set the return value of the application-defined function to be
+** a text string which is represented as UTF-8, UTF-16 native byte order,
+** UTF-16 little endian, or UTF-16 big endian, respectively.
+** ^The sqlite3_result_text64() interface sets the return value of an
+** application-defined function to be a text string in an encoding
+** specified by the fifth (and last) parameter, which must be one
+** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
+** ^SQLite takes the text result from the application from
+** the 2nd parameter of the sqlite3_result_text* interfaces.
+** ^If the 3rd parameter to any of the sqlite3_result_text* interfaces
+** other than sqlite3_result_text64() is negative, then SQLite computes
+** the string length itself by searching the 2nd parameter for the first
+** zero character.
+** ^If the 3rd parameter to the sqlite3_result_text* interfaces
+** is non-negative, then as many bytes (not characters) of the text
+** pointed to by the 2nd parameter are taken as the application-defined
+** function result.  If the 3rd parameter is non-negative, then it
+** must be the byte offset into the string where the NUL terminator would
+** appear if the string where NUL terminated.  If any NUL characters occur
+** in the string at a byte offset that is less than the value of the 3rd
+** parameter, then the resulting string will contain embedded NULs and the
+** result of expressions operating on strings with embedded NULs is undefined.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
+** function as the destructor on the text or BLOB result when it has
+** finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
+** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
+** assumes that the text or BLOB result is in constant space and does not
+** copy the content of the parameter nor call a destructor on the content
+** when it has finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
+** then SQLite makes a copy of the result into space obtained
+** from [sqlite3_malloc()] before it returns.
+**
+** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
+** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
+** when the encoding is not UTF8, if the input UTF16 begins with a
+** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
+** string and the rest of the string is interpreted according to the
+** byte-order specified by the BOM.  ^The byte-order specified by
+** the BOM at the beginning of the text overrides the byte-order
+** specified by the interface procedure.  ^So, for example, if
+** sqlite3_result_text16le() is invoked with text that begins
+** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
+** first two bytes of input are skipped and the remaining input
+** is interpreted as UTF16BE text.
+**
+** ^For UTF16 input text to the sqlite3_result_text16(),
+** sqlite3_result_text16be(), sqlite3_result_text16le(), and
+** sqlite3_result_text64() routines, if the text contains invalid
+** UTF16 characters, the invalid characters might be converted
+** into the unicode replacement character, U+FFFD.
+**
+** ^The sqlite3_result_value() interface sets the result of
+** the application-defined function to be a copy of the
+** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
+** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
+** so that the [sqlite3_value] specified in the parameter may change or
+** be deallocated after sqlite3_result_value() returns without harm.
+** ^A [protected sqlite3_value] object may always be used where an
+** [unprotected sqlite3_value] object is required, so either
+** kind of [sqlite3_value] object can be used with this interface.
+**
+** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
+** SQL NULL value, just like [sqlite3_result_null(C)], except that it
+** also associates the host-language pointer P or type T with that
+** NULL value such that the pointer can be retrieved within an
+** [application-defined SQL function] using [sqlite3_value_pointer()].
+** ^If the D parameter is not NULL, then it is a pointer to a destructor
+** for the P parameter.  ^SQLite invokes D with P as its only argument
+** when SQLite is finished with P.  The T parameter should be a static
+** string and preferably a string literal. The sqlite3_result_pointer()
+** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
+**
+** If these routines are called from within the different thread
+** than the one containing the application-defined function that received
+** the [sqlite3_context] pointer, the results are undefined.
+*/
+SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
+                           sqlite3_uint64,void(*)(void*));
+SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
+SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
+SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
+SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
+SQLITE_API void sqlite3_result_null(sqlite3_context*);
+SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
+                           void(*)(void*), unsigned char encoding);
+SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
+SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
+SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
+SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
+
+
+/*
+** CAPI3REF: Setting The Subtype Of An SQL Function
+** METHOD: sqlite3_context
+**
+** The sqlite3_result_subtype(C,T) function causes the subtype of
+** the result from the [application-defined SQL function] with
+** [sqlite3_context] C to be the value T.  Only the lower 8 bits
+** of the subtype T are preserved in current versions of SQLite;
+** higher order bits are discarded.
+** The number of subtype bytes preserved by SQLite might increase
+** in future releases of SQLite.
+**
+** Every [application-defined SQL function] that invokes this interface
+** should include the [SQLITE_RESULT_SUBTYPE] property in its
+** text encoding argument when the SQL function is
+** [sqlite3_create_function|registered].  If the [SQLITE_RESULT_SUBTYPE]
+** property is omitted from the function that invokes sqlite3_result_subtype(),
+** then in some cases the sqlite3_result_subtype() might fail to set
+** the result subtype.
+**
+** If SQLite is compiled with -DSQLITE_STRICT_SUBTYPE=1, then any
+** SQL function that invokes the sqlite3_result_subtype() interface
+** and that does not have the SQLITE_RESULT_SUBTYPE property will raise
+** an error.  Future versions of SQLite might enable -DSQLITE_STRICT_SUBTYPE=1
+** by default.
+*/
+SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
+
+/*
+** CAPI3REF: Define New Collating Sequences
+** METHOD: sqlite3
+**
+** ^These functions add, remove, or modify a [collation] associated
+** with the [database connection] specified as the first argument.
+**
+** ^The name of the collation is a UTF-8 string
+** for sqlite3_create_collation() and sqlite3_create_collation_v2()
+** and a UTF-16 string in native byte order for sqlite3_create_collation16().
+** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
+** considered to be the same name.
+**
+** ^(The third argument (eTextRep) must be one of the constants:
+** <ul>
+** <li> [SQLITE_UTF8],
+** <li> [SQLITE_UTF16LE],
+** <li> [SQLITE_UTF16BE],
+** <li> [SQLITE_UTF16], or
+** <li> [SQLITE_UTF16_ALIGNED].
+** </ul>)^
+** ^The eTextRep argument determines the encoding of strings passed
+** to the collating function callback, xCompare.
+** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
+** force strings to be UTF16 with native byte order.
+** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
+** on an even byte address.
+**
+** ^The fourth argument, pArg, is an application data pointer that is passed
+** through as the first argument to the collating function callback.
+**
+** ^The fifth argument, xCompare, is a pointer to the collating function.
+** ^Multiple collating functions can be registered using the same name but
+** with different eTextRep parameters and SQLite will use whichever
+** function requires the least amount of data transformation.
+** ^If the xCompare argument is NULL then the collating function is
+** deleted.  ^When all collating functions having the same name are deleted,
+** that collation is no longer usable.
+**
+** ^The collating function callback is invoked with a copy of the pArg
+** application data pointer and with two strings in the encoding specified
+** by the eTextRep argument.  The two integer parameters to the collating
+** function callback are the length of the two strings, in bytes. The collating
+** function must return an integer that is negative, zero, or positive
+** if the first string is less than, equal to, or greater than the second,
+** respectively.  A collating function must always return the same answer
+** given the same inputs.  If two or more collating functions are registered
+** to the same collation name (using different eTextRep values) then all
+** must give an equivalent answer when invoked with equivalent strings.
+** The collating function must obey the following properties for all
+** strings A, B, and C:
+**
+** <ol>
+** <li> If A==B then B==A.
+** <li> If A==B and B==C then A==C.
+** <li> If A<B THEN B>A.
+** <li> If A<B and B<C then A<C.
+** </ol>
+**
+** If a collating function fails any of the above constraints and that
+** collating function is registered and used, then the behavior of SQLite
+** is undefined.
+**
+** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
+** with the addition that the xDestroy callback is invoked on pArg when
+** the collating function is deleted.
+** ^Collating functions are deleted when they are overridden by later
+** calls to the collation creation functions or when the
+** [database connection] is closed using [sqlite3_close()].
+**
+** ^The xDestroy callback is <u>not</u> called if the
+** sqlite3_create_collation_v2() function fails.  Applications that invoke
+** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
+** check the return code and dispose of the application data pointer
+** themselves rather than expecting SQLite to deal with it for them.
+** This is different from every other SQLite interface.  The inconsistency
+** is unfortunate but cannot be changed without breaking backwards
+** compatibility.
+**
+** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
+*/
+SQLITE_API int sqlite3_create_collation(
+  sqlite3*,
+  const char *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+SQLITE_API int sqlite3_create_collation_v2(
+  sqlite3*,
+  const char *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDestroy)(void*)
+);
+SQLITE_API int sqlite3_create_collation16(
+  sqlite3*,
+  const void *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+
+/*
+** CAPI3REF: Collation Needed Callbacks
+** METHOD: sqlite3
+**
+** ^To avoid having to register all collation sequences before a database
+** can be used, a single callback function may be registered with the
+** [database connection] to be invoked whenever an undefined collation
+** sequence is required.
+**
+** ^If the function is registered using the sqlite3_collation_needed() API,
+** then it is passed the names of undefined collation sequences as strings
+** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
+** the names are passed as UTF-16 in machine native byte order.
+** ^A call to either function replaces the existing collation-needed callback.
+**
+** ^(When the callback is invoked, the first argument passed is a copy
+** of the second argument to sqlite3_collation_needed() or
+** sqlite3_collation_needed16().  The second argument is the database
+** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
+** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
+** sequence function required.  The fourth parameter is the name of the
+** required collation sequence.)^
+**
+** The callback function should register the desired collation using
+** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
+** [sqlite3_create_collation_v2()].
+*/
+SQLITE_API int sqlite3_collation_needed(
+  sqlite3*,
+  void*,
+  void(*)(void*,sqlite3*,int eTextRep,const char*)
+);
+SQLITE_API int sqlite3_collation_needed16(
+  sqlite3*,
+  void*,
+  void(*)(void*,sqlite3*,int eTextRep,const void*)
+);
+
+#ifdef SQLITE_ENABLE_CEROD
+/*
+** Specify the activation key for a CEROD database.  Unless
+** activated, none of the CEROD routines will work.
+*/
+SQLITE_API void sqlite3_activate_cerod(
+  const char *zPassPhrase        /* Activation phrase */
+);
+#endif
+
+/*
+** CAPI3REF: Suspend Execution For A Short Time
+**
+** The sqlite3_sleep() function causes the current thread to suspend execution
+** for at least a number of milliseconds specified in its parameter.
+**
+** If the operating system does not support sleep requests with
+** millisecond time resolution, then the time will be rounded up to
+** the nearest second. The number of milliseconds of sleep actually
+** requested from the operating system is returned.
+**
+** ^SQLite implements this interface by calling the xSleep()
+** method of the default [sqlite3_vfs] object.  If the xSleep() method
+** of the default VFS is not implemented correctly, or not implemented at
+** all, then the behavior of sqlite3_sleep() may deviate from the description
+** in the previous paragraphs.
+**
+** If a negative argument is passed to sqlite3_sleep() the results vary by
+** VFS and operating system.  Some system treat a negative argument as an
+** instruction to sleep forever.  Others understand it to mean do not sleep
+** at all. ^In SQLite version 3.42.0 and later, a negative
+** argument passed into sqlite3_sleep() is changed to zero before it is relayed
+** down into the xSleep method of the VFS.
+*/
+SQLITE_API int sqlite3_sleep(int);
+
+/*
+** CAPI3REF: Name Of The Folder Holding Temporary Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all temporary files
+** created by SQLite when using a built-in [sqlite3_vfs | VFS]
+** will be placed in that directory.)^  ^If this variable
+** is a NULL pointer, then SQLite performs a search for an appropriate
+** temporary file directory.
+**
+** Applications are strongly discouraged from using this global variable.
+** It is required to set a temporary folder on Windows Runtime (WinRT).
+** But for all other platforms, it is highly recommended that applications
+** neither read nor write this variable.  This global variable is a relic
+** that exists for backwards compatibility of legacy applications and should
+** be avoided in new projects.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [temp_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [temp_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [temp_store_directory pragma] should be avoided.
+** Except when requested by the [temp_store_directory pragma], SQLite
+** does not free the memory that sqlite3_temp_directory points to.  If
+** the application wants that memory to be freed, it must do
+** so itself, taking care to only do so after all [database connection]
+** objects have been destroyed.
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
+** features that require the use of temporary files may fail.  Here is an
+** example of how to do this using C++ with the Windows Runtime:
+**
+** <blockquote><pre>
+** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
+**       TemporaryFolder->Path->Data();
+** char zPathBuf[MAX_PATH + 1];
+** memset(zPathBuf, 0, sizeof(zPathBuf));
+** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
+**       NULL, NULL);
+** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
+** </pre></blockquote>
+*/
+SQLITE_API char *sqlite3_temp_directory;
+
+/*
+** CAPI3REF: Name Of The Folder Holding Database Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all database files
+** specified with a relative pathname and created or accessed by
+** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
+** to be relative to that directory.)^ ^If this variable is a NULL
+** pointer, then SQLite assumes that all database files specified
+** with a relative pathname are relative to the current directory
+** for the process.  Only the windows VFS makes use of this global
+** variable; it is ignored by the unix VFS.
+**
+** Changing the value of this variable while a database connection is
+** open can result in a corrupt database.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [data_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [data_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [data_store_directory pragma] should be avoided.
+*/
+SQLITE_API char *sqlite3_data_directory;
+
+/*
+** CAPI3REF: Win32 Specific Interface
+**
+** These interfaces are available only on Windows.  The
+** [sqlite3_win32_set_directory] interface is used to set the value associated
+** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
+** zValue, depending on the value of the type parameter.  The zValue parameter
+** should be NULL to cause the previous value to be freed via [sqlite3_free];
+** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
+** prior to being used.  The [sqlite3_win32_set_directory] interface returns
+** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
+** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
+** [sqlite3_data_directory] variable is intended to act as a replacement for
+** the current directory on the sub-platforms of Win32 where that concept is
+** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
+** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
+** sqlite3_win32_set_directory interface except the string parameter must be
+** UTF-8 or UTF-16, respectively.
+*/
+SQLITE_API int sqlite3_win32_set_directory(
+  unsigned long type, /* Identifier for directory being set or reset */
+  void *zValue        /* New value for directory being set or reset */
+);
+SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
+SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
+
+/*
+** CAPI3REF: Win32 Directory Types
+**
+** These macros are only available on Windows.  They define the allowed values
+** for the type argument to the [sqlite3_win32_set_directory] interface.
+*/
+#define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
+#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
+
+/*
+** CAPI3REF: Test For Auto-Commit Mode
+** KEYWORDS: {autocommit mode}
+** METHOD: sqlite3
+**
+** ^The sqlite3_get_autocommit() interface returns non-zero or
+** zero if the given database connection is or is not in autocommit mode,
+** respectively.  ^Autocommit mode is on by default.
+** ^Autocommit mode is disabled by a [BEGIN] statement.
+** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
+**
+** If certain kinds of errors occur on a statement within a multi-statement
+** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
+** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
+** transaction might be rolled back automatically.  The only way to
+** find out whether SQLite automatically rolled back the transaction after
+** an error is to use this function.
+**
+** If another thread changes the autocommit status of the database
+** connection while this routine is running, then the return value
+** is undefined.
+*/
+SQLITE_API int sqlite3_get_autocommit(sqlite3*);
+
+/*
+** CAPI3REF: Find The Database Handle Of A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_db_handle interface returns the [database connection] handle
+** to which a [prepared statement] belongs.  ^The [database connection]
+** returned by sqlite3_db_handle is the same [database connection]
+** that was the first argument
+** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
+** create the statement in the first place.
+*/
+SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Return The Schema Name For A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
+** for the N-th database on database connection D, or a NULL pointer of N is
+** out of range.  An N value of 0 means the main database file.  An N of 1 is
+** the "temp" schema.  Larger values of N correspond to various ATTACH-ed
+** databases.
+**
+** Space to hold the string that is returned by sqlite3_db_name() is managed
+** by SQLite itself.  The string might be deallocated by any operation that
+** changes the schema, including [ATTACH] or [DETACH] or calls to
+** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
+** occur on a different thread.  Applications that need to
+** remember the string long-term should make their own copy.  Applications that
+** are accessing the same database connection simultaneously on multiple
+** threads should mutex-protect calls to this API and should make their own
+** private copy of the result prior to releasing the mutex.
+*/
+SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Return The Filename For A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
+** associated with database N of connection D.
+** ^If there is no attached database N on the database
+** connection D, or if database N is a temporary or in-memory database, then
+** this function will return either a NULL pointer or an empty string.
+**
+** ^The string value returned by this routine is owned and managed by
+** the database connection.  ^The value will be valid until the database N
+** is [DETACH]-ed or until the database connection closes.
+**
+** ^The filename returned by this function is the output of the
+** xFullPathname method of the [VFS].  ^In other words, the filename
+** will be an absolute pathname, even if the filename used
+** to open the database originally was a URI or relative pathname.
+**
+** If the filename pointer returned by this routine is not NULL, then it
+** can be used as the filename input parameter to these routines:
+** <ul>
+** <li> [sqlite3_uri_parameter()]
+** <li> [sqlite3_uri_boolean()]
+** <li> [sqlite3_uri_int64()]
+** <li> [sqlite3_filename_database()]
+** <li> [sqlite3_filename_journal()]
+** <li> [sqlite3_filename_wal()]
+** </ul>
+*/
+SQLITE_API sqlite3_filename sqlite3_db_filename(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine if a database is read-only
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
+** of connection D is read-only, 0 if it is read/write, or -1 if N is not
+** the name of a database on connection D.
+*/
+SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine the transaction state of a database
+** METHOD: sqlite3
+**
+** ^The sqlite3_txn_state(D,S) interface returns the current
+** [transaction state] of schema S in database connection D.  ^If S is NULL,
+** then the highest transaction state of any schema on database connection D
+** is returned.  Transaction states are (in order of lowest to highest):
+** <ol>
+** <li value="0"> SQLITE_TXN_NONE
+** <li value="1"> SQLITE_TXN_READ
+** <li value="2"> SQLITE_TXN_WRITE
+** </ol>
+** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
+** a valid schema, then -1 is returned.
+*/
+SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
+
+/*
+** CAPI3REF: Allowed return values from sqlite3_txn_state()
+** KEYWORDS: {transaction state}
+**
+** These constants define the current transaction state of a database file.
+** ^The [sqlite3_txn_state(D,S)] interface returns one of these
+** constants in order to describe the transaction state of schema S
+** in [database connection] D.
+**
+** <dl>
+** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
+** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
+** pending.</dd>
+**
+** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
+** <dd>The SQLITE_TXN_READ state means that the database is currently
+** in a read transaction.  Content has been read from the database file
+** but nothing in the database file has changed.  The transaction state
+** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
+** no other conflicting concurrent write transactions.  The transaction
+** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
+** [COMMIT].</dd>
+**
+** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
+** <dd>The SQLITE_TXN_WRITE state means that the database is currently
+** in a write transaction.  Content has been written to the database file
+** but has not yet committed.  The transaction state will change to
+** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
+*/
+#define SQLITE_TXN_NONE  0
+#define SQLITE_TXN_READ  1
+#define SQLITE_TXN_WRITE 2
+
+/*
+** CAPI3REF: Find the next prepared statement
+** METHOD: sqlite3
+**
+** ^This interface returns a pointer to the next [prepared statement] after
+** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
+** then this interface returns a pointer to the first prepared statement
+** associated with the database connection pDb.  ^If no prepared statement
+** satisfies the conditions of this routine, it returns NULL.
+**
+** The [database connection] pointer D in a call to
+** [sqlite3_next_stmt(D,S)] must refer to an open database
+** connection and in particular must not be a NULL pointer.
+*/
+SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Commit And Rollback Notification Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_commit_hook() interface registers a callback
+** function to be invoked whenever a transaction is [COMMIT | committed].
+** ^Any callback set by a previous call to sqlite3_commit_hook()
+** for the same database connection is overridden.
+** ^The sqlite3_rollback_hook() interface registers a callback
+** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
+** ^Any callback set by a previous call to sqlite3_rollback_hook()
+** for the same database connection is overridden.
+** ^The pArg argument is passed through to the callback.
+** ^If the callback on a commit hook function returns non-zero,
+** then the commit is converted into a rollback.
+**
+** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
+** return the P argument from the previous call of the same function
+** on the same [database connection] D, or NULL for
+** the first call for each function on D.
+**
+** The commit and rollback hook callbacks are not reentrant.
+** The callback implementation must not do anything that will modify
+** the database connection that invoked the callback.  Any actions
+** to modify the database connection must be deferred until after the
+** completion of the [sqlite3_step()] call that triggered the commit
+** or rollback hook in the first place.
+** Note that running any other SQL statements, including SELECT statements,
+** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
+** the database connections for the meaning of "modify" in this paragraph.
+**
+** ^Registering a NULL function disables the callback.
+**
+** ^When the commit hook callback routine returns zero, the [COMMIT]
+** operation is allowed to continue normally.  ^If the commit hook
+** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
+** ^The rollback hook is invoked on a rollback that results from a commit
+** hook returning non-zero, just as it would be with any other rollback.
+**
+** ^For the purposes of this API, a transaction is said to have been
+** rolled back if an explicit "ROLLBACK" statement is executed, or
+** an error or constraint causes an implicit rollback to occur.
+** ^The rollback callback is not invoked if a transaction is
+** automatically rolled back because the database connection is closed.
+**
+** See also the [sqlite3_update_hook()] interface.
+*/
+SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
+SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
+
+/*
+** CAPI3REF: Autovacuum Compaction Amount Callback
+** METHOD: sqlite3
+**
+** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
+** function C that is invoked prior to each autovacuum of the database
+** file.  ^The callback is passed a copy of the generic data pointer (P),
+** the schema-name of the attached database that is being autovacuumed,
+** the size of the database file in pages, the number of free pages,
+** and the number of bytes per page, respectively.  The callback should
+** return the number of free pages that should be removed by the
+** autovacuum.  ^If the callback returns zero, then no autovacuum happens.
+** ^If the value returned is greater than or equal to the number of
+** free pages, then a complete autovacuum happens.
+**
+** <p>^If there are multiple ATTACH-ed database files that are being
+** modified as part of a transaction commit, then the autovacuum pages
+** callback is invoked separately for each file.
+**
+** <p><b>The callback is not reentrant.</b> The callback function should
+** not attempt to invoke any other SQLite interface.  If it does, bad
+** things may happen, including segmentation faults and corrupt database
+** files.  The callback function should be a simple function that
+** does some arithmetic on its input parameters and returns a result.
+**
+** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
+** destructor for the P parameter.  ^If X is not NULL, then X(P) is
+** invoked whenever the database connection closes or when the callback
+** is overwritten by another invocation of sqlite3_autovacuum_pages().
+**
+** <p>^There is only one autovacuum pages callback per database connection.
+** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
+** previous invocations for that database connection.  ^If the callback
+** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
+** then the autovacuum steps callback is canceled.  The return value
+** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
+** be some other error code if something goes wrong.  The current
+** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
+** return codes might be added in future releases.
+**
+** <p>If no autovacuum pages callback is specified (the usual case) or
+** a NULL pointer is provided for the callback,
+** then the default behavior is to vacuum all free pages.  So, in other
+** words, the default behavior is the same as if the callback function
+** were something like this:
+**
+** <blockquote><pre>
+**     unsigned int demonstration_autovac_pages_callback(
+**       void *pClientData,
+**       const char *zSchema,
+**       unsigned int nDbPage,
+**       unsigned int nFreePage,
+**       unsigned int nBytePerPage
+**     ){
+**       return nFreePage;
+**     }
+** </pre></blockquote>
+*/
+SQLITE_API int sqlite3_autovacuum_pages(
+  sqlite3 *db,
+  unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
+  void*,
+  void(*)(void*)
+);
+
+
+/*
+** CAPI3REF: Data Change Notification Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_update_hook() interface registers a callback function
+** with the [database connection] identified by the first argument
+** to be invoked whenever a row is updated, inserted or deleted in
+** a [rowid table].
+** ^Any callback set by a previous call to this function
+** for the same database connection is overridden.
+**
+** ^The second argument is a pointer to the function to invoke when a
+** row is updated, inserted or deleted in a rowid table.
+** ^The first argument to the callback is a copy of the third argument
+** to sqlite3_update_hook().
+** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
+** or [SQLITE_UPDATE], depending on the operation that caused the callback
+** to be invoked.
+** ^The third and fourth arguments to the callback contain pointers to the
+** database and table name containing the affected row.
+** ^The final callback parameter is the [rowid] of the row.
+** ^In the case of an update, this is the [rowid] after the update takes place.
+**
+** ^(The update hook is not invoked when internal system tables are
+** modified (i.e. sqlite_sequence).)^
+** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
+**
+** ^In the current implementation, the update hook
+** is not invoked when conflicting rows are deleted because of an
+** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
+** invoked when rows are deleted using the [truncate optimization].
+** The exceptions defined in this paragraph might change in a future
+** release of SQLite.
+**
+** Whether the update hook is invoked before or after the
+** corresponding change is currently unspecified and may differ
+** depending on the type of change. Do not rely on the order of the
+** hook call with regards to the final result of the operation which
+** triggers the hook.
+**
+** The update hook implementation must not do anything that will modify
+** the database connection that invoked the update hook.  Any actions
+** to modify the database connection must be deferred until after the
+** completion of the [sqlite3_step()] call that triggered the update hook.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** ^The sqlite3_update_hook(D,C,P) function
+** returns the P argument from the previous call
+** on the same [database connection] D, or NULL for
+** the first call on D.
+**
+** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
+** and [sqlite3_preupdate_hook()] interfaces.
+*/
+SQLITE_API void *sqlite3_update_hook(
+  sqlite3*,
+  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
+  void*
+);
+
+/*
+** CAPI3REF: Enable Or Disable Shared Pager Cache
+**
+** ^(This routine enables or disables the sharing of the database cache
+** and schema data structures between [database connection | connections]
+** to the same database. Sharing is enabled if the argument is true
+** and disabled if the argument is false.)^
+**
+** This interface is omitted if SQLite is compiled with
+** [-DSQLITE_OMIT_SHARED_CACHE].  The [-DSQLITE_OMIT_SHARED_CACHE]
+** compile-time option is recommended because the
+** [use of shared cache mode is discouraged].
+**
+** ^Cache sharing is enabled and disabled for an entire process.
+** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
+** In prior versions of SQLite,
+** sharing was enabled or disabled for each thread separately.
+**
+** ^(The cache sharing mode set by this interface effects all subsequent
+** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
+** Existing database connections continue to use the sharing mode
+** that was in effect at the time they were opened.)^
+**
+** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
+** successfully.  An [error code] is returned otherwise.)^
+**
+** ^Shared cache is disabled by default. It is recommended that it stay
+** that way.  In other words, do not use this routine.  This interface
+** continues to be provided for historical compatibility, but its use is
+** discouraged.  Any use of shared cache is discouraged.  If shared cache
+** must be used, it is recommended that shared cache only be enabled for
+** individual database connections using the [sqlite3_open_v2()] interface
+** with the [SQLITE_OPEN_SHAREDCACHE] flag.
+**
+** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
+** and will always return SQLITE_MISUSE. On those systems,
+** shared cache mode should be enabled per-database connection via
+** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
+**
+** This interface is threadsafe on processors where writing a
+** 32-bit integer is atomic.
+**
+** See Also:  [SQLite Shared-Cache Mode]
+*/
+SQLITE_API int sqlite3_enable_shared_cache(int);
+
+/*
+** CAPI3REF: Attempt To Free Heap Memory
+**
+** ^The sqlite3_release_memory() interface attempts to free N bytes
+** of heap memory by deallocating non-essential memory allocations
+** held by the database library.   Memory used to cache database
+** pages to improve performance is an example of non-essential memory.
+** ^sqlite3_release_memory() returns the number of bytes actually freed,
+** which might be more or less than the amount requested.
+** ^The sqlite3_release_memory() routine is a no-op returning zero
+** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
+**
+** See also: [sqlite3_db_release_memory()]
+*/
+SQLITE_API int sqlite3_release_memory(int);
+
+/*
+** CAPI3REF: Free Memory Used By A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
+** memory as possible from database connection D. Unlike the
+** [sqlite3_release_memory()] interface, this interface is in effect even
+** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
+** omitted.
+**
+** See also: [sqlite3_release_memory()]
+*/
+SQLITE_API int sqlite3_db_release_memory(sqlite3*);
+
+/*
+** CAPI3REF: Impose A Limit On Heap Size
+**
+** These interfaces impose limits on the amount of heap memory that will be
+** by all database connections within a single process.
+**
+** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
+** soft limit on the amount of heap memory that may be allocated by SQLite.
+** ^SQLite strives to keep heap memory utilization below the soft heap
+** limit by reducing the number of pages held in the page cache
+** as heap memory usages approaches the limit.
+** ^The soft heap limit is "soft" because even though SQLite strives to stay
+** below the limit, it will exceed the limit rather than generate
+** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
+** is advisory only.
+**
+** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
+** N bytes on the amount of memory that will be allocated.  ^The
+** sqlite3_hard_heap_limit64(N) interface is similar to
+** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
+** when the hard heap limit is reached.
+**
+** ^The return value from both sqlite3_soft_heap_limit64() and
+** sqlite3_hard_heap_limit64() is the size of
+** the heap limit prior to the call, or negative in the case of an
+** error.  ^If the argument N is negative
+** then no change is made to the heap limit.  Hence, the current
+** size of heap limits can be determined by invoking
+** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
+**
+** ^Setting the heap limits to zero disables the heap limiter mechanism.
+**
+** ^The soft heap limit may not be greater than the hard heap limit.
+** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
+** is invoked with a value of N that is greater than the hard heap limit,
+** the soft heap limit is set to the value of the hard heap limit.
+** ^The soft heap limit is automatically enabled whenever the hard heap
+** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
+** the soft heap limit is outside the range of 1..N, then the soft heap
+** limit is set to N.  ^Invoking sqlite3_soft_heap_limit64(0) when the
+** hard heap limit is enabled makes the soft heap limit equal to the
+** hard heap limit.
+**
+** The memory allocation limits can also be adjusted using
+** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
+**
+** ^(The heap limits are not enforced in the current implementation
+** if one or more of following conditions are true:
+**
+** <ul>
+** <li> The limit value is set to zero.
+** <li> Memory accounting is disabled using a combination of the
+**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
+**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
+** <li> An alternative page cache implementation is specified using
+**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
+** <li> The page cache allocates from its own memory pool supplied
+**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
+**      from the heap.
+** </ul>)^
+**
+** The circumstances under which SQLite will enforce the heap limits may
+** changes in future releases of SQLite.
+*/
+SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
+SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
+
+/*
+** CAPI3REF: Deprecated Soft Heap Limit Interface
+** DEPRECATED
+**
+** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
+** interface.  This routine is provided for historical compatibility
+** only.  All new applications should use the
+** [sqlite3_soft_heap_limit64()] interface rather than this one.
+*/
+SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
+
+
+/*
+** CAPI3REF: Extract Metadata About A Column Of A Table
+** METHOD: sqlite3
+**
+** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
+** information about column C of table T in database D
+** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
+** interface returns SQLITE_OK and fills in the non-NULL pointers in
+** the final five arguments with appropriate values if the specified
+** column exists.  ^The sqlite3_table_column_metadata() interface returns
+** SQLITE_ERROR if the specified column does not exist.
+** ^If the column-name parameter to sqlite3_table_column_metadata() is a
+** NULL pointer, then this routine simply checks for the existence of the
+** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
+** does not.  If the table name parameter T in a call to
+** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
+** undefined behavior.
+**
+** ^The column is identified by the second, third and fourth parameters to
+** this function. ^(The second parameter is either the name of the database
+** (i.e. "main", "temp", or an attached database) containing the specified
+** table or NULL.)^ ^If it is NULL, then all attached databases are searched
+** for the table using the same algorithm used by the database engine to
+** resolve unqualified table references.
+**
+** ^The third and fourth parameters to this function are the table and column
+** name of the desired column, respectively.
+**
+** ^Metadata is returned by writing to the memory locations passed as the 5th
+** and subsequent parameters to this function. ^Any of these arguments may be
+** NULL, in which case the corresponding element of metadata is omitted.
+**
+** ^(<blockquote>
+** <table border="1">
+** <tr><th> Parameter <th> Output<br>Type <th>  Description
+**
+** <tr><td> 5th <td> const char* <td> Data type
+** <tr><td> 6th <td> const char* <td> Name of default collation sequence
+** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
+** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
+** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
+** </table>
+** </blockquote>)^
+**
+** ^The memory pointed to by the character pointers returned for the
+** declaration type and collation sequence is valid until the next
+** call to any SQLite API function.
+**
+** ^If the specified table is actually a view, an [error code] is returned.
+**
+** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
+** is not a [WITHOUT ROWID] table and an
+** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
+** parameters are set for the explicitly declared column. ^(If there is no
+** [INTEGER PRIMARY KEY] column, then the outputs
+** for the [rowid] are set as follows:
+**
+** <pre>
+**     data type: "INTEGER"
+**     collation sequence: "BINARY"
+**     not null: 0
+**     primary key: 1
+**     auto increment: 0
+** </pre>)^
+**
+** ^This function causes all database schemas to be read from disk and
+** parsed, if that has not already been done, and returns an error if
+** any errors are encountered while loading the schema.
+*/
+SQLITE_API int sqlite3_table_column_metadata(
+  sqlite3 *db,                /* Connection handle */
+  const char *zDbName,        /* Database name or NULL */
+  const char *zTableName,     /* Table name */
+  const char *zColumnName,    /* Column name */
+  char const **pzDataType,    /* OUTPUT: Declared data type */
+  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
+  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
+  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
+  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
+);
+
+/*
+** CAPI3REF: Load An Extension
+** METHOD: sqlite3
+**
+** ^This interface loads an SQLite extension library from the named file.
+**
+** ^The sqlite3_load_extension() interface attempts to load an
+** [SQLite extension] library contained in the file zFile.  If
+** the file cannot be loaded directly, attempts are made to load
+** with various operating-system specific extensions added.
+** So for example, if "samplelib" cannot be loaded, then names like
+** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
+** be tried also.
+**
+** ^The entry point is zProc.
+** ^(zProc may be 0, in which case SQLite will try to come up with an
+** entry point name on its own.  It first tries "sqlite3_extension_init".
+** If that does not work, it constructs a name "sqlite3_X_init" where the
+** X is consists of the lower-case equivalent of all ASCII alphabetic
+** characters in the filename from the last "/" to the first following
+** "." and omitting any initial "lib".)^
+** ^The sqlite3_load_extension() interface returns
+** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
+** ^If an error occurs and pzErrMsg is not 0, then the
+** [sqlite3_load_extension()] interface shall attempt to
+** fill *pzErrMsg with error message text stored in memory
+** obtained from [sqlite3_malloc()]. The calling function
+** should free this memory by calling [sqlite3_free()].
+**
+** ^Extension loading must be enabled using
+** [sqlite3_enable_load_extension()] or
+** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
+** prior to calling this API,
+** otherwise an error will be returned.
+**
+** <b>Security warning:</b> It is recommended that the
+** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
+** interface.  The use of the [sqlite3_enable_load_extension()] interface
+** should be avoided.  This will keep the SQL function [load_extension()]
+** disabled and prevent SQL injections from giving attackers
+** access to extension loading capabilities.
+**
+** See also the [load_extension() SQL function].
+*/
+SQLITE_API int sqlite3_load_extension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+);
+
+/*
+** CAPI3REF: Enable Or Disable Extension Loading
+** METHOD: sqlite3
+**
+** ^So as not to open security holes in older applications that are
+** unprepared to deal with [extension loading], and as a means of disabling
+** [extension loading] while evaluating user-entered SQL, the following API
+** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
+**
+** ^Extension loading is off by default.
+** ^Call the sqlite3_enable_load_extension() routine with onoff==1
+** to turn extension loading on and call it with onoff==0 to turn
+** it back off again.
+**
+** ^This interface enables or disables both the C-API
+** [sqlite3_load_extension()] and the SQL function [load_extension()].
+** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
+** to enable or disable only the C-API.)^
+**
+** <b>Security warning:</b> It is recommended that extension loading
+** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
+** rather than this interface, so the [load_extension()] SQL function
+** remains disabled. This will prevent SQL injections from giving attackers
+** access to extension loading capabilities.
+*/
+SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
+
+/*
+** CAPI3REF: Automatically Load Statically Linked Extensions
+**
+** ^This interface causes the xEntryPoint() function to be invoked for
+** each new [database connection] that is created.  The idea here is that
+** xEntryPoint() is the entry point for a statically linked [SQLite extension]
+** that is to be automatically loaded into all new database connections.
+**
+** ^(Even though the function prototype shows that xEntryPoint() takes
+** no arguments and returns void, SQLite invokes xEntryPoint() with three
+** arguments and expects an integer result as if the signature of the
+** entry point where as follows:
+**
+** <blockquote><pre>
+**    int xEntryPoint(
+**      sqlite3 *db,
+**      const char **pzErrMsg,
+**      const struct sqlite3_api_routines *pThunk
+**    );
+** </pre></blockquote>)^
+**
+** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
+** point to an appropriate error message (obtained from [sqlite3_mprintf()])
+** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
+** is NULL before calling the xEntryPoint().  ^SQLite will invoke
+** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
+** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
+** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
+**
+** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
+** on the list of automatic extensions is a harmless no-op. ^No entry point
+** will be called more than once for each database connection that is opened.
+**
+** See also: [sqlite3_reset_auto_extension()]
+** and [sqlite3_cancel_auto_extension()]
+*/
+SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
+
+/*
+** CAPI3REF: Cancel Automatic Extension Loading
+**
+** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
+** initialization routine X that was registered using a prior call to
+** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
+** routine returns 1 if initialization routine X was successfully
+** unregistered and it returns 0 if X was not on the list of initialization
+** routines.
+*/
+SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
+
+/*
+** CAPI3REF: Reset Automatic Extension Loading
+**
+** ^This interface disables all automatic extensions previously
+** registered using [sqlite3_auto_extension()].
+*/
+SQLITE_API void sqlite3_reset_auto_extension(void);
+
+/*
+** Structures used by the virtual table interface
+*/
+typedef struct sqlite3_vtab sqlite3_vtab;
+typedef struct sqlite3_index_info sqlite3_index_info;
+typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
+typedef struct sqlite3_module sqlite3_module;
+
+/*
+** CAPI3REF: Virtual Table Object
+** KEYWORDS: sqlite3_module {virtual table module}
+**
+** This structure, sometimes called a "virtual table module",
+** defines the implementation of a [virtual table].
+** This structure consists mostly of methods for the module.
+**
+** ^A virtual table module is created by filling in a persistent
+** instance of this structure and passing a pointer to that instance
+** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
+** ^The registration remains valid until it is replaced by a different
+** module or until the [database connection] closes.  The content
+** of this structure must not change while it is registered with
+** any database connection.
+*/
+struct sqlite3_module {
+  int iVersion;
+  int (*xCreate)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xConnect)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
+  int (*xDisconnect)(sqlite3_vtab *pVTab);
+  int (*xDestroy)(sqlite3_vtab *pVTab);
+  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
+  int (*xClose)(sqlite3_vtab_cursor*);
+  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
+                int argc, sqlite3_value **argv);
+  int (*xNext)(sqlite3_vtab_cursor*);
+  int (*xEof)(sqlite3_vtab_cursor*);
+  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
+  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
+  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
+  int (*xBegin)(sqlite3_vtab *pVTab);
+  int (*xSync)(sqlite3_vtab *pVTab);
+  int (*xCommit)(sqlite3_vtab *pVTab);
+  int (*xRollback)(sqlite3_vtab *pVTab);
+  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
+                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
+                       void **ppArg);
+  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
+  /* The methods above are in version 1 of the sqlite_module object. Those
+  ** below are for version 2 and greater. */
+  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
+  int (*xRelease)(sqlite3_vtab *pVTab, int);
+  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
+  /* The methods above are in versions 1 and 2 of the sqlite_module object.
+  ** Those below are for version 3 and greater. */
+  int (*xShadowName)(const char*);
+  /* The methods above are in versions 1 through 3 of the sqlite_module object.
+  ** Those below are for version 4 and greater. */
+  int (*xIntegrity)(sqlite3_vtab *pVTab, const char *zSchema,
+                    const char *zTabName, int mFlags, char **pzErr);
+};
+
+/*
+** CAPI3REF: Virtual Table Indexing Information
+** KEYWORDS: sqlite3_index_info
+**
+** The sqlite3_index_info structure and its substructures is used as part
+** of the [virtual table] interface to
+** pass information into and receive the reply from the [xBestIndex]
+** method of a [virtual table module].  The fields under **Inputs** are the
+** inputs to xBestIndex and are read-only.  xBestIndex inserts its
+** results into the **Outputs** fields.
+**
+** ^(The aConstraint[] array records WHERE clause constraints of the form:
+**
+** <blockquote>column OP expr</blockquote>
+**
+** where OP is =, <, <=, >, or >=.)^  ^(The particular operator is
+** stored in aConstraint[].op using one of the
+** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
+** ^(The index of the column is stored in
+** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
+** expr on the right-hand side can be evaluated (and thus the constraint
+** is usable) and false if it cannot.)^
+**
+** ^The optimizer automatically inverts terms of the form "expr OP column"
+** and makes other simplifications to the WHERE clause in an attempt to
+** get as many WHERE clause terms into the form shown above as possible.
+** ^The aConstraint[] array only reports WHERE clause terms that are
+** relevant to the particular virtual table being queried.
+**
+** ^Information about the ORDER BY clause is stored in aOrderBy[].
+** ^Each term of aOrderBy records a column of the ORDER BY clause.
+**
+** The colUsed field indicates which columns of the virtual table may be
+** required by the current scan. Virtual table columns are numbered from
+** zero in the order in which they appear within the CREATE TABLE statement
+** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
+** the corresponding bit is set within the colUsed mask if the column may be
+** required by SQLite. If the table has at least 64 columns and any column
+** to the right of the first 63 is required, then bit 63 of colUsed is also
+** set. In other words, column iCol may be required if the expression
+** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
+** non-zero.
+**
+** The [xBestIndex] method must fill aConstraintUsage[] with information
+** about what parameters to pass to xFilter.  ^If argvIndex>0 then
+** the right-hand side of the corresponding aConstraint[] is evaluated
+** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
+** is true, then the constraint is assumed to be fully handled by the
+** virtual table and might not be checked again by the byte code.)^ ^(The
+** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
+** is left in its default setting of false, the constraint will always be
+** checked separately in byte code.  If the omit flag is change to true, then
+** the constraint may or may not be checked in byte code.  In other words,
+** when the omit flag is true there is no guarantee that the constraint will
+** not be checked again using byte code.)^
+**
+** ^The idxNum and idxStr values are recorded and passed into the
+** [xFilter] method.
+** ^[sqlite3_free()] is used to free idxStr if and only if
+** needToFreeIdxStr is true.
+**
+** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
+** the correct order to satisfy the ORDER BY clause so that no separate
+** sorting step is required.
+**
+** ^The estimatedCost value is an estimate of the cost of a particular
+** strategy. A cost of N indicates that the cost of the strategy is similar
+** to a linear scan of an SQLite table with N rows. A cost of log(N)
+** indicates that the expense of the operation is similar to that of a
+** binary search on a unique indexed field of an SQLite table with N rows.
+**
+** ^The estimatedRows value is an estimate of the number of rows that
+** will be returned by the strategy.
+**
+** The xBestIndex method may optionally populate the idxFlags field with a
+** mask of SQLITE_INDEX_SCAN_* flags. One such flag is
+** [SQLITE_INDEX_SCAN_HEX], which if set causes the [EXPLAIN QUERY PLAN]
+** output to show the idxNum has hex instead of as decimal.  Another flag is
+** SQLITE_INDEX_SCAN_UNIQUE, which if set indicates that the query plan will
+** return at most one row.
+**
+** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
+** SQLite also assumes that if a call to the xUpdate() method is made as
+** part of the same statement to delete or update a virtual table row and the
+** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
+** any database changes. In other words, if the xUpdate() returns
+** SQLITE_CONSTRAINT, the database contents must be exactly as they were
+** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
+** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
+** the xUpdate method are automatically rolled back by SQLite.
+**
+** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
+** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
+** If a virtual table extension is
+** used with an SQLite version earlier than 3.8.2, the results of attempting
+** to read or write the estimatedRows field are undefined (but are likely
+** to include crashing the application). The estimatedRows field should
+** therefore only be used if [sqlite3_libversion_number()] returns a
+** value greater than or equal to 3008002. Similarly, the idxFlags field
+** was added for [version 3.9.0] ([dateof:3.9.0]).
+** It may therefore only be used if
+** sqlite3_libversion_number() returns a value greater than or equal to
+** 3009000.
+*/
+struct sqlite3_index_info {
+  /* Inputs */
+  int nConstraint;           /* Number of entries in aConstraint */
+  struct sqlite3_index_constraint {
+     int iColumn;              /* Column constrained.  -1 for ROWID */
+     unsigned char op;         /* Constraint operator */
+     unsigned char usable;     /* True if this constraint is usable */
+     int iTermOffset;          /* Used internally - xBestIndex should ignore */
+  } *aConstraint;            /* Table of WHERE clause constraints */
+  int nOrderBy;              /* Number of terms in the ORDER BY clause */
+  struct sqlite3_index_orderby {
+     int iColumn;              /* Column number */
+     unsigned char desc;       /* True for DESC.  False for ASC. */
+  } *aOrderBy;               /* The ORDER BY clause */
+  /* Outputs */
+  struct sqlite3_index_constraint_usage {
+    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
+    unsigned char omit;      /* Do not code a test for this constraint */
+  } *aConstraintUsage;
+  int idxNum;                /* Number used to identify the index */
+  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
+  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
+  int orderByConsumed;       /* True if output is already ordered */
+  double estimatedCost;           /* Estimated cost of using this index */
+  /* Fields below are only available in SQLite 3.8.2 and later */
+  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
+  /* Fields below are only available in SQLite 3.9.0 and later */
+  int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
+  /* Fields below are only available in SQLite 3.10.0 and later */
+  sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
+};
+
+/*
+** CAPI3REF: Virtual Table Scan Flags
+**
+** Virtual table implementations are allowed to set the
+** [sqlite3_index_info].idxFlags field to some combination of
+** these bits.
+*/
+#define SQLITE_INDEX_SCAN_UNIQUE 0x00000001 /* Scan visits at most 1 row */
+#define SQLITE_INDEX_SCAN_HEX    0x00000002 /* Display idxNum as hex */
+                                            /* in EXPLAIN QUERY PLAN */
+
+/*
+** CAPI3REF: Virtual Table Constraint Operator Codes
+**
+** These macros define the allowed values for the
+** [sqlite3_index_info].aConstraint[].op field.  Each value represents
+** an operator that is part of a constraint term in the WHERE clause of
+** a query that uses a [virtual table].
+**
+** ^The left-hand operand of the operator is given by the corresponding
+** aConstraint[].iColumn field.  ^An iColumn of -1 indicates the left-hand
+** operand is the rowid.
+** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
+** operators have no left-hand operand, and so for those operators the
+** corresponding aConstraint[].iColumn is meaningless and should not be
+** used.
+**
+** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
+** value 255 are reserved to represent functions that are overloaded
+** by the [xFindFunction|xFindFunction method] of the virtual table
+** implementation.
+**
+** The right-hand operands for each constraint might be accessible using
+** the [sqlite3_vtab_rhs_value()] interface.  Usually the right-hand
+** operand is only available if it appears as a single constant literal
+** in the input SQL.  If the right-hand operand is another column or an
+** expression (even a constant expression) or a parameter, then the
+** sqlite3_vtab_rhs_value() probably will not be able to extract it.
+** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
+** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
+** and hence calls to sqlite3_vtab_rhs_value() for those operators will
+** always return SQLITE_NOTFOUND.
+**
+** The collating sequence to be used for comparison can be found using
+** the [sqlite3_vtab_collation()] interface.  For most real-world virtual
+** tables, the collating sequence of constraints does not matter (for example
+** because the constraints are numeric) and so the sqlite3_vtab_collation()
+** interface is not commonly needed.
+*/
+#define SQLITE_INDEX_CONSTRAINT_EQ          2
+#define SQLITE_INDEX_CONSTRAINT_GT          4
+#define SQLITE_INDEX_CONSTRAINT_LE          8
+#define SQLITE_INDEX_CONSTRAINT_LT         16
+#define SQLITE_INDEX_CONSTRAINT_GE         32
+#define SQLITE_INDEX_CONSTRAINT_MATCH      64
+#define SQLITE_INDEX_CONSTRAINT_LIKE       65
+#define SQLITE_INDEX_CONSTRAINT_GLOB       66
+#define SQLITE_INDEX_CONSTRAINT_REGEXP     67
+#define SQLITE_INDEX_CONSTRAINT_NE         68
+#define SQLITE_INDEX_CONSTRAINT_ISNOT      69
+#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL  70
+#define SQLITE_INDEX_CONSTRAINT_ISNULL     71
+#define SQLITE_INDEX_CONSTRAINT_IS         72
+#define SQLITE_INDEX_CONSTRAINT_LIMIT      73
+#define SQLITE_INDEX_CONSTRAINT_OFFSET     74
+#define SQLITE_INDEX_CONSTRAINT_FUNCTION  150
+
+/*
+** CAPI3REF: Register A Virtual Table Implementation
+** METHOD: sqlite3
+**
+** ^These routines are used to register a new [virtual table module] name.
+** ^Module names must be registered before
+** creating a new [virtual table] using the module and before using a
+** preexisting [virtual table] for the module.
+**
+** ^The module name is registered on the [database connection] specified
+** by the first parameter.  ^The name of the module is given by the
+** second parameter.  ^The third parameter is a pointer to
+** the implementation of the [virtual table module].   ^The fourth
+** parameter is an arbitrary client data pointer that is passed through
+** into the [xCreate] and [xConnect] methods of the virtual table module
+** when a new virtual table is be being created or reinitialized.
+**
+** ^The sqlite3_create_module_v2() interface has a fifth parameter which
+** is a pointer to a destructor for the pClientData.  ^SQLite will
+** invoke the destructor function (if it is not NULL) when SQLite
+** no longer needs the pClientData pointer.  ^The destructor will also
+** be invoked if the call to sqlite3_create_module_v2() fails.
+** ^The sqlite3_create_module()
+** interface is equivalent to sqlite3_create_module_v2() with a NULL
+** destructor.
+**
+** ^If the third parameter (the pointer to the sqlite3_module object) is
+** NULL then no new module is created and any existing modules with the
+** same name are dropped.
+**
+** See also: [sqlite3_drop_modules()]
+*/
+SQLITE_API int sqlite3_create_module(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData          /* Client data for xCreate/xConnect */
+);
+SQLITE_API int sqlite3_create_module_v2(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData,         /* Client data for xCreate/xConnect */
+  void(*xDestroy)(void*)     /* Module destructor function */
+);
+
+/*
+** CAPI3REF: Remove Unnecessary Virtual Table Implementations
+** METHOD: sqlite3
+**
+** ^The sqlite3_drop_modules(D,L) interface removes all virtual
+** table modules from database connection D except those named on list L.
+** The L parameter must be either NULL or a pointer to an array of pointers
+** to strings where the array is terminated by a single NULL pointer.
+** ^If the L parameter is NULL, then all virtual table modules are removed.
+**
+** See also: [sqlite3_create_module()]
+*/
+SQLITE_API int sqlite3_drop_modules(
+  sqlite3 *db,                /* Remove modules from this connection */
+  const char **azKeep         /* Except, do not remove the ones named here */
+);
+
+/*
+** CAPI3REF: Virtual Table Instance Object
+** KEYWORDS: sqlite3_vtab
+**
+** Every [virtual table module] implementation uses a subclass
+** of this object to describe a particular instance
+** of the [virtual table].  Each subclass will
+** be tailored to the specific needs of the module implementation.
+** The purpose of this superclass is to define certain fields that are
+** common to all module implementations.
+**
+** ^Virtual tables methods can set an error message by assigning a
+** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
+** take care that any prior string is freed by a call to [sqlite3_free()]
+** prior to assigning a new string to zErrMsg.  ^After the error message
+** is delivered up to the client application, the string will be automatically
+** freed by sqlite3_free() and the zErrMsg field will be zeroed.
+*/
+struct sqlite3_vtab {
+  const sqlite3_module *pModule;  /* The module for this virtual table */
+  int nRef;                       /* Number of open cursors */
+  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Virtual Table Cursor Object
+** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
+**
+** Every [virtual table module] implementation uses a subclass of the
+** following structure to describe cursors that point into the
+** [virtual table] and are used
+** to loop through the virtual table.  Cursors are created using the
+** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
+** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
+** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
+** of the module.  Each module implementation will define
+** the content of a cursor structure to suit its own needs.
+**
+** This superclass exists in order to define fields of the cursor that
+** are common to all implementations.
+*/
+struct sqlite3_vtab_cursor {
+  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Declare The Schema Of A Virtual Table
+**
+** ^The [xCreate] and [xConnect] methods of a
+** [virtual table module] call this interface
+** to declare the format (the names and datatypes of the columns) of
+** the virtual tables they implement.
+*/
+SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
+
+/*
+** CAPI3REF: Overload A Function For A Virtual Table
+** METHOD: sqlite3
+**
+** ^(Virtual tables can provide alternative implementations of functions
+** using the [xFindFunction] method of the [virtual table module].
+** But global versions of those functions
+** must exist in order to be overloaded.)^
+**
+** ^(This API makes sure a global version of a function with a particular
+** name and number of parameters exists.  If no such function exists
+** before this API is called, a new function is created.)^  ^The implementation
+** of the new function always causes an exception to be thrown.  So
+** the new function is not good for anything by itself.  Its only
+** purpose is to be a placeholder function that can be overloaded
+** by a [virtual table].
+*/
+SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
+
+/*
+** CAPI3REF: A Handle To An Open BLOB
+** KEYWORDS: {BLOB handle} {BLOB handles}
+**
+** An instance of this object represents an open BLOB on which
+** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
+** ^Objects of this type are created by [sqlite3_blob_open()]
+** and destroyed by [sqlite3_blob_close()].
+** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
+** can be used to read or write small subsections of the BLOB.
+** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
+*/
+typedef struct sqlite3_blob sqlite3_blob;
+
+/*
+** CAPI3REF: Open A BLOB For Incremental I/O
+** METHOD: sqlite3
+** CONSTRUCTOR: sqlite3_blob
+**
+** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
+** in row iRow, column zColumn, table zTable in database zDb;
+** in other words, the same BLOB that would be selected by:
+**
+** <pre>
+**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
+** </pre>)^
+**
+** ^(Parameter zDb is not the filename that contains the database, but
+** rather the symbolic name of the database. For attached databases, this is
+** the name that appears after the AS keyword in the [ATTACH] statement.
+** For the main database file, the database name is "main". For TEMP
+** tables, the database name is "temp".)^
+**
+** ^If the flags parameter is non-zero, then the BLOB is opened for read
+** and write access. ^If the flags parameter is zero, the BLOB is opened for
+** read-only access.
+**
+** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
+** in *ppBlob. Otherwise an [error code] is returned and, unless the error
+** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
+** the API is not misused, it is always safe to call [sqlite3_blob_close()]
+** on *ppBlob after this function it returns.
+**
+** This function fails with SQLITE_ERROR if any of the following are true:
+** <ul>
+**   <li> ^(Database zDb does not exist)^,
+**   <li> ^(Table zTable does not exist within database zDb)^,
+**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
+**   <li> ^(Column zColumn does not exist)^,
+**   <li> ^(Row iRow is not present in the table)^,
+**   <li> ^(The specified column of row iRow contains a value that is not
+**         a TEXT or BLOB value)^,
+**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
+**         constraint and the blob is being opened for read/write access)^,
+**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
+**         column zColumn is part of a [child key] definition and the blob is
+**         being opened for read/write access)^.
+** </ul>
+**
+** ^Unless it returns SQLITE_MISUSE, this function sets the
+** [database connection] error code and message accessible via
+** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
+**
+** A BLOB referenced by sqlite3_blob_open() may be read using the
+** [sqlite3_blob_read()] interface and modified by using
+** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
+** different row of the same table using the [sqlite3_blob_reopen()]
+** interface.  However, the column, table, or database of a [BLOB handle]
+** cannot be changed after the [BLOB handle] is opened.
+**
+** ^(If the row that a BLOB handle points to is modified by an
+** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
+** then the BLOB handle is marked as "expired".
+** This is true if any column of the row is changed, even a column
+** other than the one the BLOB handle is open on.)^
+** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
+** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
+** ^(Changes written into a BLOB prior to the BLOB expiring are not
+** rolled back by the expiration of the BLOB.  Such changes will eventually
+** commit if the transaction continues to completion.)^
+**
+** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
+** the opened blob.  ^The size of a blob may not be changed by this
+** interface.  Use the [UPDATE] SQL command to change the size of a
+** blob.
+**
+** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
+** and the built-in [zeroblob] SQL function may be used to create a
+** zero-filled blob to read or write using the incremental-blob interface.
+**
+** To avoid a resource leak, every open [BLOB handle] should eventually
+** be released by a call to [sqlite3_blob_close()].
+**
+** See also: [sqlite3_blob_close()],
+** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
+** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
+*/
+SQLITE_API int sqlite3_blob_open(
+  sqlite3*,
+  const char *zDb,
+  const char *zTable,
+  const char *zColumn,
+  sqlite3_int64 iRow,
+  int flags,
+  sqlite3_blob **ppBlob
+);
+
+/*
+** CAPI3REF: Move a BLOB Handle to a New Row
+** METHOD: sqlite3_blob
+**
+** ^This function is used to move an existing [BLOB handle] so that it points
+** to a different row of the same database table. ^The new row is identified
+** by the rowid value passed as the second argument. Only the row can be
+** changed. ^The database, table and column on which the blob handle is open
+** remain the same. Moving an existing [BLOB handle] to a new row is
+** faster than closing the existing handle and opening a new one.
+**
+** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
+** it must exist and there must be either a blob or text value stored in
+** the nominated column.)^ ^If the new row is not present in the table, or if
+** it does not contain a blob or text value, or if another error occurs, an
+** SQLite error code is returned and the blob handle is considered aborted.
+** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
+** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
+** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
+** always returns zero.
+**
+** ^This function sets the database handle error code and message.
+*/
+SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
+
+/*
+** CAPI3REF: Close A BLOB Handle
+** DESTRUCTOR: sqlite3_blob
+**
+** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
+** unconditionally.  Even if this routine returns an error code, the
+** handle is still closed.)^
+**
+** ^If the blob handle being closed was opened for read-write access, and if
+** the database is in auto-commit mode and there are no other open read-write
+** blob handles or active write statements, the current transaction is
+** committed. ^If an error occurs while committing the transaction, an error
+** code is returned and the transaction rolled back.
+**
+** Calling this function with an argument that is not a NULL pointer or an
+** open blob handle results in undefined behavior. ^Calling this routine
+** with a null pointer (such as would be returned by a failed call to
+** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
+** is passed a valid open blob handle, the values returned by the
+** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
+*/
+SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
+
+/*
+** CAPI3REF: Return The Size Of An Open BLOB
+** METHOD: sqlite3_blob
+**
+** ^Returns the size in bytes of the BLOB accessible via the
+** successfully opened [BLOB handle] in its only argument.  ^The
+** incremental blob I/O routines can only read or overwriting existing
+** blob content; they cannot change the size of a blob.
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+*/
+SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
+
+/*
+** CAPI3REF: Read Data From A BLOB Incrementally
+** METHOD: sqlite3_blob
+**
+** ^(This function is used to read data from an open [BLOB handle] into a
+** caller-supplied buffer. N bytes of data are copied into buffer Z
+** from the open BLOB, starting at offset iOffset.)^
+**
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
+** less than zero, [SQLITE_ERROR] is returned and no data is read.
+** ^The size of the blob (and hence the maximum value of N+iOffset)
+** can be determined using the [sqlite3_blob_bytes()] interface.
+**
+** ^An attempt to read from an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].
+**
+** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
+** Otherwise, an [error code] or an [extended error code] is returned.)^
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+**
+** See also: [sqlite3_blob_write()].
+*/
+SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
+
+/*
+** CAPI3REF: Write Data Into A BLOB Incrementally
+** METHOD: sqlite3_blob
+**
+** ^(This function is used to write data into an open [BLOB handle] from a
+** caller-supplied buffer. N bytes of data are copied from the buffer Z
+** into the open BLOB, starting at offset iOffset.)^
+**
+** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
+** Otherwise, an  [error code] or an [extended error code] is returned.)^
+** ^Unless SQLITE_MISUSE is returned, this function sets the
+** [database connection] error code and message accessible via
+** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
+**
+** ^If the [BLOB handle] passed as the first argument was not opened for
+** writing (the flags parameter to [sqlite3_blob_open()] was zero),
+** this function returns [SQLITE_READONLY].
+**
+** This function may only modify the contents of the BLOB; it is
+** not possible to increase the size of a BLOB using this API.
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is written. The size of the
+** BLOB (and hence the maximum value of N+iOffset) can be determined
+** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
+** than zero [SQLITE_ERROR] is returned and no data is written.
+**
+** ^An attempt to write to an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
+** before the [BLOB handle] expired are not rolled back by the
+** expiration of the handle, though of course those changes might
+** have been overwritten by the statement that expired the BLOB handle
+** or by other independent statements.
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+**
+** See also: [sqlite3_blob_read()].
+*/
+SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
+
+/*
+** CAPI3REF: Virtual File System Objects
+**
+** A virtual filesystem (VFS) is an [sqlite3_vfs] object
+** that SQLite uses to interact
+** with the underlying operating system.  Most SQLite builds come with a
+** single default VFS that is appropriate for the host computer.
+** New VFSes can be registered and existing VFSes can be unregistered.
+** The following interfaces are provided.
+**
+** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
+** ^Names are case sensitive.
+** ^Names are zero-terminated UTF-8 strings.
+** ^If there is no match, a NULL pointer is returned.
+** ^If zVfsName is NULL then the default VFS is returned.
+**
+** ^New VFSes are registered with sqlite3_vfs_register().
+** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
+** ^The same VFS can be registered multiple times without injury.
+** ^To make an existing VFS into the default VFS, register it again
+** with the makeDflt flag set.  If two different VFSes with the
+** same name are registered, the behavior is undefined.  If a
+** VFS is registered with a name that is NULL or an empty string,
+** then the behavior is undefined.
+**
+** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
+** ^(If the default VFS is unregistered, another VFS is chosen as
+** the default.  The choice for the new VFS is arbitrary.)^
+*/
+SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
+SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
+SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
+
+/*
+** CAPI3REF: Mutexes
+**
+** The SQLite core uses these routines for thread
+** synchronization. Though they are intended for internal
+** use by SQLite, code that links against SQLite is
+** permitted to use any of these routines.
+**
+** The SQLite source code contains multiple implementations
+** of these mutex routines.  An appropriate implementation
+** is selected automatically at compile-time.  The following
+** implementations are available in the SQLite core:
+**
+** <ul>
+** <li>   SQLITE_MUTEX_PTHREADS
+** <li>   SQLITE_MUTEX_W32
+** <li>   SQLITE_MUTEX_NOOP
+** </ul>
+**
+** The SQLITE_MUTEX_NOOP implementation is a set of routines
+** that does no real locking and is appropriate for use in
+** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
+** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
+** and Windows.
+**
+** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
+** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
+** implementation is included with the library. In this case the
+** application must supply a custom mutex implementation using the
+** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
+** before calling sqlite3_initialize() or any other public sqlite3_
+** function that calls sqlite3_initialize().
+**
+** ^The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
+** routine returns NULL if it is unable to allocate the requested
+** mutex.  The argument to sqlite3_mutex_alloc() must one of these
+** integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MAIN
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_OPEN
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
+** <li>  SQLITE_MUTEX_STATIC_APP1
+** <li>  SQLITE_MUTEX_STATIC_APP2
+** <li>  SQLITE_MUTEX_STATIC_APP3
+** <li>  SQLITE_MUTEX_STATIC_VFS1
+** <li>  SQLITE_MUTEX_STATIC_VFS2
+** <li>  SQLITE_MUTEX_STATIC_VFS3
+** </ul>
+**
+** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
+** cause sqlite3_mutex_alloc() to create
+** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
+** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
+** a pointer to a static preexisting mutex.  ^Nine static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  ^For the static
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+**
+** ^The sqlite3_mutex_free() routine deallocates a previously
+** allocated dynamic mutex.  Attempting to deallocate a static
+** mutex results in undefined behavior.
+**
+** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  ^If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
+** upon successful entry.  ^(Mutexes created using
+** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
+** In such cases, the
+** mutex must be exited an equal number of times before another thread
+** can enter.)^  If the same thread tries to enter any mutex other
+** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
+**
+** ^(Some systems (for example, Windows 95) do not support the operation
+** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
+** will always return SQLITE_BUSY. In most cases the SQLite core only uses
+** sqlite3_mutex_try() as an optimization, so this is acceptable
+** behavior. The exceptions are unix builds that set the
+** SQLITE_ENABLE_SETLK_TIMEOUT build option. In that case a working
+** sqlite3_mutex_try() is required.)^
+**
+** ^The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.   The behavior
+** is undefined if the mutex is not currently entered by the
+** calling thread or is not currently allocated.
+**
+** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(),
+** sqlite3_mutex_leave(), or sqlite3_mutex_free() is a NULL pointer,
+** then any of the four routines behaves as a no-op.
+**
+** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
+
+/*
+** CAPI3REF: Mutex Methods Object
+**
+** An instance of this structure defines the low-level routines
+** used to allocate and use mutexes.
+**
+** Usually, the default mutex implementations provided by SQLite are
+** sufficient, however the application has the option of substituting a custom
+** implementation for specialized deployments or systems for which SQLite
+** does not provide a suitable implementation. In this case, the application
+** creates and populates an instance of this structure to pass
+** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
+** Additionally, an instance of this structure can be used as an
+** output variable when querying the system for the current mutex
+** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
+**
+** ^The xMutexInit method defined by this structure is invoked as
+** part of system initialization by the sqlite3_initialize() function.
+** ^The xMutexInit routine is called by SQLite exactly once for each
+** effective call to [sqlite3_initialize()].
+**
+** ^The xMutexEnd method defined by this structure is invoked as
+** part of system shutdown by the sqlite3_shutdown() function. The
+** implementation of this method is expected to release all outstanding
+** resources obtained by the mutex methods implementation, especially
+** those obtained by the xMutexInit method.  ^The xMutexEnd()
+** interface is invoked exactly once for each call to [sqlite3_shutdown()].
+**
+** ^(The remaining seven methods defined by this structure (xMutexAlloc,
+** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
+** xMutexNotheld) implement the following interfaces (respectively):
+**
+** <ul>
+**   <li>  [sqlite3_mutex_alloc()] </li>
+**   <li>  [sqlite3_mutex_free()] </li>
+**   <li>  [sqlite3_mutex_enter()] </li>
+**   <li>  [sqlite3_mutex_try()] </li>
+**   <li>  [sqlite3_mutex_leave()] </li>
+**   <li>  [sqlite3_mutex_held()] </li>
+**   <li>  [sqlite3_mutex_notheld()] </li>
+** </ul>)^
+**
+** The only difference is that the public sqlite3_XXX functions enumerated
+** above silently ignore any invocations that pass a NULL pointer instead
+** of a valid mutex handle. The implementations of the methods defined
+** by this structure are not required to handle this case. The results
+** of passing a NULL pointer instead of a valid mutex handle are undefined
+** (i.e. it is acceptable to provide an implementation that segfaults if
+** it is passed a NULL pointer).
+**
+** The xMutexInit() method must be threadsafe.  It must be harmless to
+** invoke xMutexInit() multiple times within the same process and without
+** intervening calls to xMutexEnd().  Second and subsequent calls to
+** xMutexInit() must be no-ops.
+**
+** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
+** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
+** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
+** memory allocation for a fast or recursive mutex.
+**
+** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
+** called, but only if the prior call to xMutexInit returned SQLITE_OK.
+** If xMutexInit fails in any way, it is expected to clean up after itself
+** prior to returning.
+*/
+typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
+struct sqlite3_mutex_methods {
+  int (*xMutexInit)(void);
+  int (*xMutexEnd)(void);
+  sqlite3_mutex *(*xMutexAlloc)(int);
+  void (*xMutexFree)(sqlite3_mutex *);
+  void (*xMutexEnter)(sqlite3_mutex *);
+  int (*xMutexTry)(sqlite3_mutex *);
+  void (*xMutexLeave)(sqlite3_mutex *);
+  int (*xMutexHeld)(sqlite3_mutex *);
+  int (*xMutexNotheld)(sqlite3_mutex *);
+};
+
+/*
+** CAPI3REF: Mutex Verification Routines
+**
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
+** are intended for use inside assert() statements.  The SQLite core
+** never uses these routines except inside an assert() and applications
+** are advised to follow the lead of the core.  The SQLite core only
+** provides implementations for these routines when it is compiled
+** with the SQLITE_DEBUG flag.  External mutex implementations
+** are only required to provide these routines if SQLITE_DEBUG is
+** defined and if NDEBUG is not defined.
+**
+** These routines should return true if the mutex in their argument
+** is held or not held, respectively, by the calling thread.
+**
+** The implementation is not required to provide versions of these
+** routines that actually work. If the implementation does not provide working
+** versions of these routines, it should at least provide stubs that always
+** return true so that one does not get spurious assertion failures.
+**
+** If the argument to sqlite3_mutex_held() is a NULL pointer then
+** the routine should return 1.   This seems counter-intuitive since
+** clearly the mutex cannot be held if it does not exist.  But
+** the reason the mutex does not exist is because the build is not
+** using mutexes.  And we do not want the assert() containing the
+** call to sqlite3_mutex_held() to fail, so a non-zero return is
+** the appropriate thing to do.  The sqlite3_mutex_notheld()
+** interface should also return 1 when given a NULL pointer.
+*/
+#ifndef NDEBUG
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
+#endif
+
+/*
+** CAPI3REF: Mutex Types
+**
+** The [sqlite3_mutex_alloc()] interface takes a single argument
+** which is one of these integer constants.
+**
+** The set of static mutexes may change from one SQLite release to the
+** next.  Applications that override the built-in mutex logic must be
+** prepared to accommodate additional static mutexes.
+*/
+#define SQLITE_MUTEX_FAST             0
+#define SQLITE_MUTEX_RECURSIVE        1
+#define SQLITE_MUTEX_STATIC_MAIN      2
+#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
+#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
+#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
+#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
+#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
+#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
+#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
+#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
+#define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
+#define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
+#define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
+
+/* Legacy compatibility: */
+#define SQLITE_MUTEX_STATIC_MASTER    2
+
+
+/*
+** CAPI3REF: Retrieve the mutex for a database connection
+** METHOD: sqlite3
+**
+** ^This interface returns a pointer the [sqlite3_mutex] object that
+** serializes access to the [database connection] given in the argument
+** when the [threading mode] is Serialized.
+** ^If the [threading mode] is Single-thread or Multi-thread then this
+** routine returns a NULL pointer.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
+
+/*
+** CAPI3REF: Low-Level Control Of Database Files
+** METHOD: sqlite3
+** KEYWORDS: {file control}
+**
+** ^The [sqlite3_file_control()] interface makes a direct call to the
+** xFileControl method for the [sqlite3_io_methods] object associated
+** with a particular database identified by the second argument. ^The
+** name of the database is "main" for the main database or "temp" for the
+** TEMP database, or the name that appears after the AS keyword for
+** databases that are added using the [ATTACH] SQL command.
+** ^A NULL pointer can be used in place of "main" to refer to the
+** main database file.
+** ^The third and fourth parameters to this routine
+** are passed directly through to the second and third parameters of
+** the xFileControl method.  ^The return value of the xFileControl
+** method becomes the return value of this routine.
+**
+** A few opcodes for [sqlite3_file_control()] are handled directly
+** by the SQLite core and never invoke the
+** sqlite3_io_methods.xFileControl method.
+** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
+** a pointer to the underlying [sqlite3_file] object to be written into
+** the space pointed to by the 4th parameter.  The
+** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
+** the [sqlite3_file] object associated with the journal file instead of
+** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
+** a pointer to the underlying [sqlite3_vfs] object for the file.
+** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
+** from the pager.
+**
+** ^If the second parameter (zDbName) does not match the name of any
+** open database file, then SQLITE_ERROR is returned.  ^This error
+** code is not remembered and will not be recalled by [sqlite3_errcode()]
+** or [sqlite3_errmsg()].  The underlying xFileControl method might
+** also return SQLITE_ERROR.  There is no way to distinguish between
+** an incorrect zDbName and an SQLITE_ERROR return from the underlying
+** xFileControl method.
+**
+** See also: [file control opcodes]
+*/
+SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
+
+/*
+** CAPI3REF: Testing Interface
+**
+** ^The sqlite3_test_control() interface is used to read out internal
+** state of SQLite and to inject faults into SQLite for testing
+** purposes.  ^The first parameter is an operation code that determines
+** the number, meaning, and operation of all subsequent parameters.
+**
+** This interface is not for use by applications.  It exists solely
+** for verifying the correct operation of the SQLite library.  Depending
+** on how the SQLite library is compiled, this interface might not exist.
+**
+** The details of the operation codes, their meanings, the parameters
+** they take, and what they do are all subject to change without notice.
+** Unlike most of the SQLite API, this function is not guaranteed to
+** operate consistently from one release to the next.
+*/
+SQLITE_API int sqlite3_test_control(int op, ...);
+
+/*
+** CAPI3REF: Testing Interface Operation Codes
+**
+** These constants are the valid operation code parameters used
+** as the first argument to [sqlite3_test_control()].
+**
+** These parameters and their meanings are subject to change
+** without notice.  These values are for testing purposes only.
+** Applications should not use any of these parameters or the
+** [sqlite3_test_control()] interface.
+*/
+#define SQLITE_TESTCTRL_FIRST                    5
+#define SQLITE_TESTCTRL_PRNG_SAVE                5
+#define SQLITE_TESTCTRL_PRNG_RESTORE             6
+#define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
+#define SQLITE_TESTCTRL_FK_NO_ACTION             7
+#define SQLITE_TESTCTRL_BITVEC_TEST              8
+#define SQLITE_TESTCTRL_FAULT_INSTALL            9
+#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
+#define SQLITE_TESTCTRL_PENDING_BYTE            11
+#define SQLITE_TESTCTRL_ASSERT                  12
+#define SQLITE_TESTCTRL_ALWAYS                  13
+#define SQLITE_TESTCTRL_RESERVE                 14  /* NOT USED */
+#define SQLITE_TESTCTRL_JSON_SELFCHECK          14
+#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
+#define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
+#define SQLITE_TESTCTRL_GETOPT                  16
+#define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
+#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
+#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
+#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
+#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
+#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
+#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
+#define SQLITE_TESTCTRL_BYTEORDER               22
+#define SQLITE_TESTCTRL_ISINIT                  23
+#define SQLITE_TESTCTRL_SORTER_MMAP             24
+#define SQLITE_TESTCTRL_IMPOSTER                25
+#define SQLITE_TESTCTRL_PARSER_COVERAGE         26
+#define SQLITE_TESTCTRL_RESULT_INTREAL          27
+#define SQLITE_TESTCTRL_PRNG_SEED               28
+#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
+#define SQLITE_TESTCTRL_SEEK_COUNT              30
+#define SQLITE_TESTCTRL_TRACEFLAGS              31
+#define SQLITE_TESTCTRL_TUNE                    32
+#define SQLITE_TESTCTRL_LOGEST                  33
+#define SQLITE_TESTCTRL_USELONGDOUBLE           34  /* NOT USED */
+#define SQLITE_TESTCTRL_LAST                    34  /* Largest TESTCTRL */
+
+/*
+** CAPI3REF: SQL Keyword Checking
+**
+** These routines provide access to the set of SQL language keywords
+** recognized by SQLite.  Applications can uses these routines to determine
+** whether or not a specific identifier needs to be escaped (for example,
+** by enclosing in double-quotes) so as not to confuse the parser.
+**
+** The sqlite3_keyword_count() interface returns the number of distinct
+** keywords understood by SQLite.
+**
+** The sqlite3_keyword_name(N,Z,L) interface finds the 0-based N-th keyword and
+** makes *Z point to that keyword expressed as UTF8 and writes the number
+** of bytes in the keyword into *L.  The string that *Z points to is not
+** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
+** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
+** or L are NULL or invalid pointers then calls to
+** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
+**
+** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
+** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
+** if it is and zero if not.
+**
+** The parser used by SQLite is forgiving.  It is often possible to use
+** a keyword as an identifier as long as such use does not result in a
+** parsing ambiguity.  For example, the statement
+** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
+** creates a new table named "BEGIN" with three columns named
+** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
+** using keywords as identifiers.  Common techniques used to avoid keyword
+** name collisions include:
+** <ul>
+** <li> Put all identifier names inside double-quotes.  This is the official
+**      SQL way to escape identifier names.
+** <li> Put identifier names inside [...].  This is not standard SQL,
+**      but it is what SQL Server does and so lots of programmers use this
+**      technique.
+** <li> Begin every identifier with the letter "Z" as no SQL keywords start
+**      with "Z".
+** <li> Include a digit somewhere in every identifier name.
+** </ul>
+**
+** Note that the number of keywords understood by SQLite can depend on
+** compile-time options.  For example, "VACUUM" is not a keyword if
+** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
+** new keywords may be added to future releases of SQLite.
+*/
+SQLITE_API int sqlite3_keyword_count(void);
+SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
+SQLITE_API int sqlite3_keyword_check(const char*,int);
+
+/*
+** CAPI3REF: Dynamic String Object
+** KEYWORDS: {dynamic string}
+**
+** An instance of the sqlite3_str object contains a dynamically-sized
+** string under construction.
+**
+** The lifecycle of an sqlite3_str object is as follows:
+** <ol>
+** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
+** <li> ^Text is appended to the sqlite3_str object using various
+** methods, such as [sqlite3_str_appendf()].
+** <li> ^The sqlite3_str object is destroyed and the string it created
+** is returned using the [sqlite3_str_finish()] interface.
+** </ol>
+*/
+typedef struct sqlite3_str sqlite3_str;
+
+/*
+** CAPI3REF: Create A New Dynamic String Object
+** CONSTRUCTOR: sqlite3_str
+**
+** ^The [sqlite3_str_new(D)] interface allocates and initializes
+** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
+** [sqlite3_str_new()] must be freed by a subsequent call to
+** [sqlite3_str_finish(X)].
+**
+** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
+** valid [sqlite3_str] object, though in the event of an out-of-memory
+** error the returned object might be a special singleton that will
+** silently reject new text, always return SQLITE_NOMEM from
+** [sqlite3_str_errcode()], always return 0 for
+** [sqlite3_str_length()], and always return NULL from
+** [sqlite3_str_finish(X)].  It is always safe to use the value
+** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
+** to any of the other [sqlite3_str] methods.
+**
+** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
+** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
+** length of the string contained in the [sqlite3_str] object will be
+** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
+** of [SQLITE_MAX_LENGTH].
+*/
+SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
+
+/*
+** CAPI3REF: Finalize A Dynamic String
+** DESTRUCTOR: sqlite3_str
+**
+** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
+** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
+** that contains the constructed string.  The calling application should
+** pass the returned value to [sqlite3_free()] to avoid a memory leak.
+** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
+** errors were encountered during construction of the string.  ^The
+** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
+** string in [sqlite3_str] object X is zero bytes long.
+*/
+SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
+
+/*
+** CAPI3REF: Add Content To A Dynamic String
+** METHOD: sqlite3_str
+**
+** These interfaces add content to an sqlite3_str object previously obtained
+** from [sqlite3_str_new()].
+**
+** ^The [sqlite3_str_appendf(X,F,...)] and
+** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
+** functionality of SQLite to append formatted text onto the end of
+** [sqlite3_str] object X.
+**
+** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
+** onto the end of the [sqlite3_str] object X.  N must be non-negative.
+** S must contain at least N non-zero bytes of content.  To append a
+** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
+** method instead.
+**
+** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
+** zero-terminated string S onto the end of [sqlite3_str] object X.
+**
+** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
+** single-byte character C onto the end of [sqlite3_str] object X.
+** ^This method can be used, for example, to add whitespace indentation.
+**
+** ^The [sqlite3_str_reset(X)] method resets the string under construction
+** inside [sqlite3_str] object X back to zero bytes in length.
+**
+** These methods do not return a result code.  ^If an error occurs, that fact
+** is recorded in the [sqlite3_str] object and can be recovered by a
+** subsequent call to [sqlite3_str_errcode(X)].
+*/
+SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
+SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
+SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
+SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
+SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
+SQLITE_API void sqlite3_str_reset(sqlite3_str*);
+
+/*
+** CAPI3REF: Status Of A Dynamic String
+** METHOD: sqlite3_str
+**
+** These interfaces return the current status of an [sqlite3_str] object.
+**
+** ^If any prior errors have occurred while constructing the dynamic string
+** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
+** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
+** [SQLITE_NOMEM] following any out-of-memory error, or
+** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
+** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
+**
+** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
+** of the dynamic string under construction in [sqlite3_str] object X.
+** ^The length returned by [sqlite3_str_length(X)] does not include the
+** zero-termination byte.
+**
+** ^The [sqlite3_str_value(X)] method returns a pointer to the current
+** content of the dynamic string under construction in X.  The value
+** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
+** and might be freed or altered by any subsequent method on the same
+** [sqlite3_str] object.  Applications must not used the pointer returned
+** [sqlite3_str_value(X)] after any subsequent method call on the same
+** object.  ^Applications may change the content of the string returned
+** by [sqlite3_str_value(X)] as long as they do not write into any bytes
+** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
+** write any byte after any subsequent sqlite3_str method call.
+*/
+SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
+SQLITE_API int sqlite3_str_length(sqlite3_str*);
+SQLITE_API char *sqlite3_str_value(sqlite3_str*);
+
+/*
+** CAPI3REF: SQLite Runtime Status
+**
+** ^These interfaces are used to retrieve runtime status information
+** about the performance of SQLite, and optionally to reset various
+** highwater marks.  ^The first argument is an integer code for
+** the specific parameter to measure.  ^(Recognized integer codes
+** are of the form [status parameters | SQLITE_STATUS_...].)^
+** ^The current value of the parameter is returned into *pCurrent.
+** ^The highest recorded value is returned in *pHighwater.  ^If the
+** resetFlag is true, then the highest record value is reset after
+** *pHighwater is written.  ^(Some parameters do not record the highest
+** value.  For those parameters
+** nothing is written into *pHighwater and the resetFlag is ignored.)^
+** ^(Other parameters record only the highwater mark and not the current
+** value.  For these latter parameters nothing is written into *pCurrent.)^
+**
+** ^The sqlite3_status() and sqlite3_status64() routines return
+** SQLITE_OK on success and a non-zero [error code] on failure.
+**
+** If either the current value or the highwater mark is too large to
+** be represented by a 32-bit integer, then the values returned by
+** sqlite3_status() are undefined.
+**
+** See also: [sqlite3_db_status()]
+*/
+SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
+SQLITE_API int sqlite3_status64(
+  int op,
+  sqlite3_int64 *pCurrent,
+  sqlite3_int64 *pHighwater,
+  int resetFlag
+);
+
+
+/*
+** CAPI3REF: Status Parameters
+** KEYWORDS: {status parameters}
+**
+** These integer constants designate various run-time status parameters
+** that can be returned by [sqlite3_status()].
+**
+** <dl>
+** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
+** <dd>This parameter is the current amount of memory checked out
+** using [sqlite3_malloc()], either directly or indirectly.  The
+** figure includes calls made to [sqlite3_malloc()] by the application
+** and internal memory usage by the SQLite library.  Auxiliary page-cache
+** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
+** this parameter.  The amount returned is the sum of the allocation
+** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
+**
+** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
+** <dd>This parameter records the largest memory allocation request
+** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
+** internal equivalents).  Only the value returned in the
+** *pHighwater parameter to [sqlite3_status()] is of interest.
+** The value written into the *pCurrent parameter is undefined.</dd>)^
+**
+** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
+** <dd>This parameter records the number of separate memory allocations
+** currently checked out.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
+** <dd>This parameter returns the number of pages used out of the
+** [pagecache memory allocator] that was configured using
+** [SQLITE_CONFIG_PAGECACHE].  The
+** value returned is in pages, not in bytes.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
+** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
+** <dd>This parameter returns the number of bytes of page cache
+** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
+** buffer and where forced to overflow to [sqlite3_malloc()].  The
+** returned value includes allocations that overflowed because they
+** where too large (they were larger than the "sz" parameter to
+** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
+** no space was left in the page cache.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
+** <dd>This parameter records the largest memory allocation request
+** handed to the [pagecache memory allocator].  Only the value returned in the
+** *pHighwater parameter to [sqlite3_status()] is of interest.
+** The value written into the *pCurrent parameter is undefined.</dd>)^
+**
+** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
+** <dd>The *pHighwater parameter records the deepest parser stack.
+** The *pCurrent value is undefined.  The *pHighwater value is only
+** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
+** </dl>
+**
+** New status parameters may be added from time to time.
+*/
+#define SQLITE_STATUS_MEMORY_USED          0
+#define SQLITE_STATUS_PAGECACHE_USED       1
+#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
+#define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
+#define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
+#define SQLITE_STATUS_MALLOC_SIZE          5
+#define SQLITE_STATUS_PARSER_STACK         6
+#define SQLITE_STATUS_PAGECACHE_SIZE       7
+#define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
+#define SQLITE_STATUS_MALLOC_COUNT         9
+
+/*
+** CAPI3REF: Database Connection Status
+** METHOD: sqlite3
+**
+** ^This interface is used to retrieve runtime status information
+** about a single [database connection].  ^The first argument is the
+** database connection object to be interrogated.  ^The second argument
+** is an integer constant, taken from the set of
+** [SQLITE_DBSTATUS options], that
+** determines the parameter to interrogate.  The set of
+** [SQLITE_DBSTATUS options] is likely
+** to grow in future releases of SQLite.
+**
+** ^The current value of the requested parameter is written into *pCur
+** and the highest instantaneous value is written into *pHiwtr.  ^If
+** the resetFlg is true, then the highest instantaneous value is
+** reset back down to the current value.
+**
+** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
+** non-zero [error code] on failure.
+**
+** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
+*/
+SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
+
+/*
+** CAPI3REF: Status Parameters for database connections
+** KEYWORDS: {SQLITE_DBSTATUS options}
+**
+** These constants are the available integer "verbs" that can be passed as
+** the second argument to the [sqlite3_db_status()] interface.
+**
+** New verbs may be added in future releases of SQLite. Existing verbs
+** might be discontinued. Applications should check the return code from
+** [sqlite3_db_status()] to make sure that the call worked.
+** The [sqlite3_db_status()] interface will return a non-zero error code
+** if a discontinued or unsupported verb is invoked.
+**
+** <dl>
+** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
+** <dd>This parameter returns the number of lookaside memory slots currently
+** checked out.</dd>)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
+** <dd>This parameter returns the number of malloc attempts that were
+** satisfied using lookaside memory. Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to the amount of
+** memory requested being larger than the lookaside slot size.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to all lookaside
+** memory already being in use.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** memory used by all pager caches associated with the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
+** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
+** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
+** pager cache is shared between two or more connections the bytes of heap
+** memory used by that pager cache is divided evenly between the attached
+** connections.)^  In other words, if none of the pager caches associated
+** with the database connection are shared, this request returns the same
+** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
+** shared, the value returned by this call will be smaller than that returned
+** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
+** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
+**
+** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** memory used to store the schema for all databases associated
+** with the connection - main, temp, and any [ATTACH]-ed databases.)^
+** ^The full amount of memory used by the schemas is reported, even if the
+** schema memory is shared with other database connections due to
+** [shared cache mode] being enabled.
+** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** and lookaside memory used by all prepared statements associated with
+** the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
+** <dd>This parameter returns the number of pager cache hits that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
+** <dd>This parameter returns the number of pager cache misses that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk. Specifically, the number of pages written to the
+** wal file in wal mode databases, or the number of pages written to the
+** database file in rollback mode databases. Any pages written as part of
+** transaction rollback or database recovery operations are not included.
+** If an IO or other error occurs while writing a page to disk, the effect
+** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
+** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk in the middle of a transaction due to the page
+** cache overflowing. Transactions are more efficient if they are written
+** to disk all at once. When pages spill mid-transaction, that introduces
+** additional overhead. This parameter can be used help identify
+** inefficiencies that can be resolved by increasing the cache size.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
+** <dd>This parameter returns zero for the current value if and only if
+** all foreign key constraints (deferred or immediate) have been
+** resolved.)^  ^The highwater mark is always 0.
+** </dd>
+** </dl>
+*/
+#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
+#define SQLITE_DBSTATUS_CACHE_USED           1
+#define SQLITE_DBSTATUS_SCHEMA_USED          2
+#define SQLITE_DBSTATUS_STMT_USED            3
+#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
+#define SQLITE_DBSTATUS_CACHE_HIT            7
+#define SQLITE_DBSTATUS_CACHE_MISS           8
+#define SQLITE_DBSTATUS_CACHE_WRITE          9
+#define SQLITE_DBSTATUS_DEFERRED_FKS        10
+#define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
+#define SQLITE_DBSTATUS_CACHE_SPILL         12
+#define SQLITE_DBSTATUS_MAX                 12   /* Largest defined DBSTATUS */
+
+
+/*
+** CAPI3REF: Prepared Statement Status
+** METHOD: sqlite3_stmt
+**
+** ^(Each prepared statement maintains various
+** [SQLITE_STMTSTATUS counters] that measure the number
+** of times it has performed specific operations.)^  These counters can
+** be used to monitor the performance characteristics of the prepared
+** statements.  For example, if the number of table steps greatly exceeds
+** the number of table searches or result rows, that would tend to indicate
+** that the prepared statement is using a full table scan rather than
+** an index.
+**
+** ^(This interface is used to retrieve and reset counter values from
+** a [prepared statement].  The first argument is the prepared statement
+** object to be interrogated.  The second argument
+** is an integer code for a specific [SQLITE_STMTSTATUS counter]
+** to be interrogated.)^
+** ^The current value of the requested counter is returned.
+** ^If the resetFlg is true, then the counter is reset to zero after this
+** interface call returns.
+**
+** See also: [sqlite3_status()] and [sqlite3_db_status()].
+*/
+SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
+
+/*
+** CAPI3REF: Status Parameters for prepared statements
+** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
+**
+** These preprocessor macros define integer codes that name counter
+** values associated with the [sqlite3_stmt_status()] interface.
+** The meanings of the various counters are as follows:
+**
+** <dl>
+** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
+** <dd>^This is the number of times that SQLite has stepped forward in
+** a table as part of a full table scan.  Large numbers for this counter
+** may indicate opportunities for performance improvement through
+** careful use of indices.</dd>
+**
+** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
+** <dd>^This is the number of sort operations that have occurred.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance through careful use of indices.</dd>
+**
+** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
+** <dd>^This is the number of rows inserted into transient indices that
+** were created automatically in order to help joins run faster.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance by adding permanent indices that do not
+** need to be reinitialized each time the statement is run.</dd>
+**
+** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
+** <dd>^This is the number of virtual machine operations executed
+** by the prepared statement if that number is less than or equal
+** to 2147483647.  The number of virtual machine operations can be
+** used as a proxy for the total work done by the prepared statement.
+** If the number of virtual machine operations exceeds 2147483647
+** then the value returned by this statement status code is undefined.
+**
+** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
+** <dd>^This is the number of times that the prepare statement has been
+** automatically regenerated due to schema changes or changes to
+** [bound parameters] that might affect the query plan.
+**
+** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
+** <dd>^This is the number of times that the prepared statement has
+** been run.  A single "run" for the purposes of this counter is one
+** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
+** The counter is incremented on the first [sqlite3_step()] call of each
+** cycle.
+**
+** [[SQLITE_STMTSTATUS_FILTER_MISS]]
+** [[SQLITE_STMTSTATUS_FILTER HIT]]
+** <dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
+** SQLITE_STMTSTATUS_FILTER_MISS</dt>
+** <dd>^SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
+** step was bypassed because a Bloom filter returned not-found.  The
+** corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
+** times that the Bloom filter returned a find, and thus the join step
+** had to be processed as normal.
+**
+** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
+** <dd>^This is the approximate number of bytes of heap memory
+** used to store the prepared statement.  ^This value is not actually
+** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
+** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
+** </dd>
+** </dl>
+*/
+#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
+#define SQLITE_STMTSTATUS_SORT              2
+#define SQLITE_STMTSTATUS_AUTOINDEX         3
+#define SQLITE_STMTSTATUS_VM_STEP           4
+#define SQLITE_STMTSTATUS_REPREPARE         5
+#define SQLITE_STMTSTATUS_RUN               6
+#define SQLITE_STMTSTATUS_FILTER_MISS       7
+#define SQLITE_STMTSTATUS_FILTER_HIT        8
+#define SQLITE_STMTSTATUS_MEMUSED           99
+
+/*
+** CAPI3REF: Custom Page Cache Object
+**
+** The sqlite3_pcache type is opaque.  It is implemented by
+** the pluggable module.  The SQLite core has no knowledge of
+** its size or internal structure and never deals with the
+** sqlite3_pcache object except by holding and passing pointers
+** to the object.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache sqlite3_pcache;
+
+/*
+** CAPI3REF: Custom Page Cache Object
+**
+** The sqlite3_pcache_page object represents a single page in the
+** page cache.  The page cache will allocate instances of this
+** object.  Various methods of the page cache use pointers to instances
+** of this object as parameters or as their return value.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache_page sqlite3_pcache_page;
+struct sqlite3_pcache_page {
+  void *pBuf;        /* The content of the page */
+  void *pExtra;      /* Extra information associated with the page */
+};
+
+/*
+** CAPI3REF: Application Defined Page Cache.
+** KEYWORDS: {page cache}
+**
+** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
+** register an alternative page cache implementation by passing in an
+** instance of the sqlite3_pcache_methods2 structure.)^
+** In many applications, most of the heap memory allocated by
+** SQLite is used for the page cache.
+** By implementing a
+** custom page cache using this API, an application can better control
+** the amount of memory consumed by SQLite, the way in which
+** that memory is allocated and released, and the policies used to
+** determine exactly which parts of a database file are cached and for
+** how long.
+**
+** The alternative page cache mechanism is an
+** extreme measure that is only needed by the most demanding applications.
+** The built-in page cache is recommended for most uses.
+**
+** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
+** internal buffer by SQLite within the call to [sqlite3_config].  Hence
+** the application may discard the parameter after the call to
+** [sqlite3_config()] returns.)^
+**
+** [[the xInit() page cache method]]
+** ^(The xInit() method is called once for each effective
+** call to [sqlite3_initialize()])^
+** (usually only once during the lifetime of the process). ^(The xInit()
+** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
+** The intent of the xInit() method is to set up global data structures
+** required by the custom page cache implementation.
+** ^(If the xInit() method is NULL, then the
+** built-in default page cache is used instead of the application defined
+** page cache.)^
+**
+** [[the xShutdown() page cache method]]
+** ^The xShutdown() method is called by [sqlite3_shutdown()].
+** It can be used to clean up
+** any outstanding resources before process shutdown, if required.
+** ^The xShutdown() method may be NULL.
+**
+** ^SQLite automatically serializes calls to the xInit method,
+** so the xInit method need not be threadsafe.  ^The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  All other methods must be threadsafe
+** in multithreaded applications.
+**
+** ^SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+**
+** [[the xCreate() page cache methods]]
+** ^SQLite invokes the xCreate() method to construct a new cache instance.
+** SQLite will typically create one cache instance for each open database file,
+** though this is not guaranteed. ^The
+** first parameter, szPage, is the size in bytes of the pages that must
+** be allocated by the cache.  ^szPage will always a power of two.  ^The
+** second parameter szExtra is a number of bytes of extra storage
+** associated with each page cache entry.  ^The szExtra parameter will
+** a number less than 250.  SQLite will use the
+** extra szExtra bytes on each page to store metadata about the underlying
+** database page on disk.  The value passed into szExtra depends
+** on the SQLite version, the target platform, and how SQLite was compiled.
+** ^The third argument to xCreate(), bPurgeable, is true if the cache being
+** created will be used to cache database pages of a file stored on disk, or
+** false if it is used for an in-memory database. The cache implementation
+** does not have to do anything special based with the value of bPurgeable;
+** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
+** never invoke xUnpin() except to deliberately delete a page.
+** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
+** false will always have the "discard" flag set to true.
+** ^Hence, a cache created with bPurgeable false will
+** never contain any unpinned pages.
+**
+** [[the xCachesize() page cache method]]
+** ^(The xCachesize() method may be called at any time by SQLite to set the
+** suggested maximum cache-size (number of pages stored by) the cache
+** instance passed as the first argument. This is the value configured using
+** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
+** parameter, the implementation is not required to do anything with this
+** value; it is advisory only.
+**
+** [[the xPagecount() page cache methods]]
+** The xPagecount() method must return the number of pages currently
+** stored in the cache, both pinned and unpinned.
+**
+** [[the xFetch() page cache methods]]
+** The xFetch() method locates a page in the cache and returns a pointer to
+** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
+** The pBuf element of the returned sqlite3_pcache_page object will be a
+** pointer to a buffer of szPage bytes used to store the content of a
+** single database page.  The pExtra element of sqlite3_pcache_page will be
+** a pointer to the szExtra bytes of extra storage that SQLite has requested
+** for each entry in the page cache.
+**
+** The page to be fetched is determined by the key. ^The minimum key value
+** is 1.  After it has been retrieved using xFetch, the page is considered
+** to be "pinned".
+**
+** If the requested page is already in the page cache, then the page cache
+** implementation must return a pointer to the page buffer with its content
+** intact.  If the requested page is not already in the cache, then the
+** cache implementation should use the value of the createFlag
+** parameter to help it determined what action to take:
+**
+** <table border=1 width=85% align=center>
+** <tr><th> createFlag <th> Behavior when page is not already in cache
+** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
+** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
+**                 Otherwise return NULL.
+** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
+**                 NULL if allocating a new page is effectively impossible.
+** </table>
+**
+** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
+** will only use a createFlag of 2 after a prior call with a createFlag of 1
+** failed.)^  In between the xFetch() calls, SQLite may
+** attempt to unpin one or more cache pages by spilling the content of
+** pinned pages to disk and synching the operating system disk cache.
+**
+** [[the xUnpin() page cache method]]
+** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
+** as its second argument.  If the third parameter, discard, is non-zero,
+** then the page must be evicted from the cache.
+** ^If the discard parameter is
+** zero, then the page may be discarded or retained at the discretion of
+** page cache implementation. ^The page cache implementation
+** may choose to evict unpinned pages at any time.
+**
+** The cache must not perform any reference counting. A single
+** call to xUnpin() unpins the page regardless of the number of prior calls
+** to xFetch().
+**
+** [[the xRekey() page cache methods]]
+** The xRekey() method is used to change the key value associated with the
+** page passed as the second argument. If the cache
+** previously contains an entry associated with newKey, it must be
+** discarded. ^Any prior cache entry associated with newKey is guaranteed not
+** to be pinned.
+**
+** When SQLite calls the xTruncate() method, the cache must discard all
+** existing cache entries with page numbers (keys) greater than or equal
+** to the value of the iLimit parameter passed to xTruncate(). If any
+** of these pages are pinned, they are implicitly unpinned, meaning that
+** they can be safely discarded.
+**
+** [[the xDestroy() page cache method]]
+** ^The xDestroy() method is used to delete a cache allocated by xCreate().
+** All resources associated with the specified cache should be freed. ^After
+** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
+** handle invalid, and will not use it with any other sqlite3_pcache_methods2
+** functions.
+**
+** [[the xShrink() page cache method]]
+** ^SQLite invokes the xShrink() method when it wants the page cache to
+** free up as much of heap memory as possible.  The page cache implementation
+** is not obligated to free any memory, but well-behaved implementations should
+** do their best.
+*/
+typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
+struct sqlite3_pcache_methods2 {
+  int iVersion;
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
+  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
+      unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+  void (*xShrink)(sqlite3_pcache*);
+};
+
+/*
+** This is the obsolete pcache_methods object that has now been replaced
+** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
+** retained in the header file for backwards compatibility only.
+*/
+typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
+struct sqlite3_pcache_methods {
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
+  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+};
+
+
+/*
+** CAPI3REF: Online Backup Object
+**
+** The sqlite3_backup object records state information about an ongoing
+** online backup operation.  ^The sqlite3_backup object is created by
+** a call to [sqlite3_backup_init()] and is destroyed by a call to
+** [sqlite3_backup_finish()].
+**
+** See Also: [Using the SQLite Online Backup API]
+*/
+typedef struct sqlite3_backup sqlite3_backup;
+
+/*
+** CAPI3REF: Online Backup API.
+**
+** The backup API copies the content of one database into another.
+** It is useful either for creating backups of databases or
+** for copying in-memory databases to or from persistent files.
+**
+** See Also: [Using the SQLite Online Backup API]
+**
+** ^SQLite holds a write transaction open on the destination database file
+** for the duration of the backup operation.
+** ^The source database is read-locked only while it is being read;
+** it is not locked continuously for the entire backup operation.
+** ^Thus, the backup may be performed on a live source database without
+** preventing other database connections from
+** reading or writing to the source database while the backup is underway.
+**
+** ^(To perform a backup operation:
+**   <ol>
+**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
+**         backup,
+**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
+**         the data between the two databases, and finally
+**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
+**         associated with the backup operation.
+**   </ol>)^
+** There should be exactly one call to sqlite3_backup_finish() for each
+** successful call to sqlite3_backup_init().
+**
+** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
+**
+** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
+** [database connection] associated with the destination database
+** and the database name, respectively.
+** ^The database name is "main" for the main database, "temp" for the
+** temporary database, or the name specified after the AS keyword in
+** an [ATTACH] statement for an attached database.
+** ^The S and M arguments passed to
+** sqlite3_backup_init(D,N,S,M) identify the [database connection]
+** and database name of the source database, respectively.
+** ^The source and destination [database connections] (parameters S and D)
+** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
+** an error.
+**
+** ^A call to sqlite3_backup_init() will fail, returning NULL, if
+** there is already a read or read-write transaction open on the
+** destination database.
+**
+** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
+** returned and an error code and error message are stored in the
+** destination [database connection] D.
+** ^The error code and message for the failed call to sqlite3_backup_init()
+** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
+** [sqlite3_errmsg16()] functions.
+** ^A successful call to sqlite3_backup_init() returns a pointer to an
+** [sqlite3_backup] object.
+** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
+** sqlite3_backup_finish() functions to perform the specified backup
+** operation.
+**
+** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
+**
+** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
+** the source and destination databases specified by [sqlite3_backup] object B.
+** ^If N is negative, all remaining source pages are copied.
+** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
+** are still more pages to be copied, then the function returns [SQLITE_OK].
+** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
+** from source to destination, then it returns [SQLITE_DONE].
+** ^If an error occurs while running sqlite3_backup_step(B,N),
+** then an [error code] is returned. ^As well as [SQLITE_OK] and
+** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
+** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
+**
+** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
+** <ol>
+** <li> the destination database was opened read-only, or
+** <li> the destination database is using write-ahead-log journaling
+** and the destination and source page sizes differ, or
+** <li> the destination database is an in-memory database and the
+** destination and source page sizes differ.
+** </ol>)^
+**
+** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
+** the [sqlite3_busy_handler | busy-handler function]
+** is invoked (if one is specified). ^If the
+** busy-handler returns non-zero before the lock is available, then
+** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
+** sqlite3_backup_step() can be retried later. ^If the source
+** [database connection]
+** is being used to write to the source database when sqlite3_backup_step()
+** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
+** case the call to sqlite3_backup_step() can be retried later on. ^(If
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
+** [SQLITE_READONLY] is returned, then
+** there is no point in retrying the call to sqlite3_backup_step(). These
+** errors are considered fatal.)^  The application must accept
+** that the backup operation has failed and pass the backup operation handle
+** to the sqlite3_backup_finish() to release associated resources.
+**
+** ^The first call to sqlite3_backup_step() obtains an exclusive lock
+** on the destination file. ^The exclusive lock is not released until either
+** sqlite3_backup_finish() is called or the backup operation is complete
+** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
+** sqlite3_backup_step() obtains a [shared lock] on the source database that
+** lasts for the duration of the sqlite3_backup_step() call.
+** ^Because the source database is not locked between calls to
+** sqlite3_backup_step(), the source database may be modified mid-way
+** through the backup process.  ^If the source database is modified by an
+** external process or via a database connection other than the one being
+** used by the backup operation, then the backup will be automatically
+** restarted by the next call to sqlite3_backup_step(). ^If the source
+** database is modified by the using the same database connection as is used
+** by the backup operation, then the backup database is automatically
+** updated at the same time.
+**
+** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
+**
+** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
+** application wishes to abandon the backup operation, the application
+** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
+** ^The sqlite3_backup_finish() interfaces releases all
+** resources associated with the [sqlite3_backup] object.
+** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
+** active write-transaction on the destination database is rolled back.
+** The [sqlite3_backup] object is invalid
+** and may not be used following a call to sqlite3_backup_finish().
+**
+** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
+** sqlite3_backup_step() errors occurred, regardless or whether or not
+** sqlite3_backup_step() completed.
+** ^If an out-of-memory condition or IO error occurred during any prior
+** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
+** sqlite3_backup_finish() returns the corresponding [error code].
+**
+** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
+** is not a permanent error and does not affect the return value of
+** sqlite3_backup_finish().
+**
+** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
+** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
+**
+** ^The sqlite3_backup_remaining() routine returns the number of pages still
+** to be backed up at the conclusion of the most recent sqlite3_backup_step().
+** ^The sqlite3_backup_pagecount() routine returns the total number of pages
+** in the source database at the conclusion of the most recent
+** sqlite3_backup_step().
+** ^(The values returned by these functions are only updated by
+** sqlite3_backup_step(). If the source database is modified in a way that
+** changes the size of the source database or the number of pages remaining,
+** those changes are not reflected in the output of sqlite3_backup_pagecount()
+** and sqlite3_backup_remaining() until after the next
+** sqlite3_backup_step().)^
+**
+** <b>Concurrent Usage of Database Handles</b>
+**
+** ^The source [database connection] may be used by the application for other
+** purposes while a backup operation is underway or being initialized.
+** ^If SQLite is compiled and configured to support threadsafe database
+** connections, then the source database connection may be used concurrently
+** from within other threads.
+**
+** However, the application must guarantee that the destination
+** [database connection] is not passed to any other API (by any thread) after
+** sqlite3_backup_init() is called and before the corresponding call to
+** sqlite3_backup_finish().  SQLite does not currently check to see
+** if the application incorrectly accesses the destination [database connection]
+** and so no error code is reported, but the operations may malfunction
+** nevertheless.  Use of the destination database connection while a
+** backup is in progress might also cause a mutex deadlock.
+**
+** If running in [shared cache mode], the application must
+** guarantee that the shared cache used by the destination database
+** is not accessed while the backup is running. In practice this means
+** that the application must guarantee that the disk file being
+** backed up to is not accessed by any connection within the process,
+** not just the specific connection that was passed to sqlite3_backup_init().
+**
+** The [sqlite3_backup] object itself is partially threadsafe. Multiple
+** threads may safely make multiple concurrent calls to sqlite3_backup_step().
+** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
+** APIs are not strictly speaking threadsafe. If they are invoked at the
+** same time as another thread is invoking sqlite3_backup_step() it is
+** possible that they return invalid values.
+**
+** <b>Alternatives To Using The Backup API</b>
+**
+** Other techniques for safely creating a consistent backup of an SQLite
+** database include:
+**
+** <ul>
+** <li> The [VACUUM INTO] command.
+** <li> The [sqlite3_rsync] utility program.
+** </ul>
+*/
+SQLITE_API sqlite3_backup *sqlite3_backup_init(
+  sqlite3 *pDest,                        /* Destination database handle */
+  const char *zDestName,                 /* Destination database name */
+  sqlite3 *pSource,                      /* Source database handle */
+  const char *zSourceName                /* Source database name */
+);
+SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
+SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
+
+/*
+** CAPI3REF: Unlock Notification
+** METHOD: sqlite3
+**
+** ^When running in shared-cache mode, a database operation may fail with
+** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
+** individual tables within the shared-cache cannot be obtained. See
+** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
+** ^This API may be used to register a callback that SQLite will invoke
+** when the connection currently holding the required lock relinquishes it.
+** ^This API is only available if the library was compiled with the
+** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
+**
+** See Also: [Using the SQLite Unlock Notification Feature].
+**
+** ^Shared-cache locks are released when a database connection concludes
+** its current transaction, either by committing it or rolling it back.
+**
+** ^When a connection (known as the blocked connection) fails to obtain a
+** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
+** identity of the database connection (the blocking connection) that
+** has locked the required resource is stored internally. ^After an
+** application receives an SQLITE_LOCKED error, it may call the
+** sqlite3_unlock_notify() method with the blocked connection handle as
+** the first argument to register for a callback that will be invoked
+** when the blocking connections current transaction is concluded. ^The
+** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
+** call that concludes the blocking connection's transaction.
+**
+** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
+** there is a chance that the blocking connection will have already
+** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
+** If this happens, then the specified callback is invoked immediately,
+** from within the call to sqlite3_unlock_notify().)^
+**
+** ^If the blocked connection is attempting to obtain a write-lock on a
+** shared-cache table, and more than one other connection currently holds
+** a read-lock on the same table, then SQLite arbitrarily selects one of
+** the other connections to use as the blocking connection.
+**
+** ^(There may be at most one unlock-notify callback registered by a
+** blocked connection. If sqlite3_unlock_notify() is called when the
+** blocked connection already has a registered unlock-notify callback,
+** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
+** called with a NULL pointer as its second argument, then any existing
+** unlock-notify callback is canceled. ^The blocked connections
+** unlock-notify callback may also be canceled by closing the blocked
+** connection using [sqlite3_close()].
+**
+** The unlock-notify callback is not reentrant. If an application invokes
+** any sqlite3_xxx API functions from within an unlock-notify callback, a
+** crash or deadlock may be the result.
+**
+** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
+** returns SQLITE_OK.
+**
+** <b>Callback Invocation Details</b>
+**
+** When an unlock-notify callback is registered, the application provides a
+** single void* pointer that is passed to the callback when it is invoked.
+** However, the signature of the callback function allows SQLite to pass
+** it an array of void* context pointers. The first argument passed to
+** an unlock-notify callback is a pointer to an array of void* pointers,
+** and the second is the number of entries in the array.
+**
+** When a blocking connection's transaction is concluded, there may be
+** more than one blocked connection that has registered for an unlock-notify
+** callback. ^If two or more such blocked connections have specified the
+** same callback function, then instead of invoking the callback function
+** multiple times, it is invoked once with the set of void* context pointers
+** specified by the blocked connections bundled together into an array.
+** This gives the application an opportunity to prioritize any actions
+** related to the set of unblocked database connections.
+**
+** <b>Deadlock Detection</b>
+**
+** Assuming that after registering for an unlock-notify callback a
+** database waits for the callback to be issued before taking any further
+** action (a reasonable assumption), then using this API may cause the
+** application to deadlock. For example, if connection X is waiting for
+** connection Y's transaction to be concluded, and similarly connection
+** Y is waiting on connection X's transaction, then neither connection
+** will proceed and the system may remain deadlocked indefinitely.
+**
+** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
+** detection. ^If a given call to sqlite3_unlock_notify() would put the
+** system in a deadlocked state, then SQLITE_LOCKED is returned and no
+** unlock-notify callback is registered. The system is said to be in
+** a deadlocked state if connection A has registered for an unlock-notify
+** callback on the conclusion of connection B's transaction, and connection
+** B has itself registered for an unlock-notify callback when connection
+** A's transaction is concluded. ^Indirect deadlock is also detected, so
+** the system is also considered to be deadlocked if connection B has
+** registered for an unlock-notify callback on the conclusion of connection
+** C's transaction, where connection C is waiting on connection A. ^Any
+** number of levels of indirection are allowed.
+**
+** <b>The "DROP TABLE" Exception</b>
+**
+** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
+** always appropriate to call sqlite3_unlock_notify(). There is however,
+** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
+** SQLite checks if there are any currently executing SELECT statements
+** that belong to the same connection. If there are, SQLITE_LOCKED is
+** returned. In this case there is no "blocking connection", so invoking
+** sqlite3_unlock_notify() results in the unlock-notify callback being
+** invoked immediately. If the application then re-attempts the "DROP TABLE"
+** or "DROP INDEX" query, an infinite loop might be the result.
+**
+** One way around this problem is to check the extended error code returned
+** by an sqlite3_step() call. ^(If there is a blocking connection, then the
+** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
+** the special "DROP TABLE/INDEX" case, the extended error code is just
+** SQLITE_LOCKED.)^
+*/
+SQLITE_API int sqlite3_unlock_notify(
+  sqlite3 *pBlocked,                          /* Waiting connection */
+  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
+  void *pNotifyArg                            /* Argument to pass to xNotify */
+);
+
+
+/*
+** CAPI3REF: String Comparison
+**
+** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
+** and extensions to compare the contents of two buffers containing UTF-8
+** strings in a case-independent fashion, using the same definition of "case
+** independence" that SQLite uses internally when comparing identifiers.
+*/
+SQLITE_API int sqlite3_stricmp(const char *, const char *);
+SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
+
+/*
+** CAPI3REF: String Globbing
+*
+** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
+** string X matches the [GLOB] pattern P.
+** ^The definition of [GLOB] pattern matching used in
+** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
+** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
+** is case sensitive.
+**
+** Note that this routine returns zero on a match and non-zero if the strings
+** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
+**
+** See also: [sqlite3_strlike()].
+*/
+SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
+
+/*
+** CAPI3REF: String LIKE Matching
+*
+** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
+** string X matches the [LIKE] pattern P with escape character E.
+** ^The definition of [LIKE] pattern matching used in
+** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
+** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
+** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
+** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
+** insensitive - equivalent upper and lower case ASCII characters match
+** one another.
+**
+** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
+** only ASCII characters are case folded.
+**
+** Note that this routine returns zero on a match and non-zero if the strings
+** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
+**
+** See also: [sqlite3_strglob()].
+*/
+SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
+
+/*
+** CAPI3REF: Error Logging Interface
+**
+** ^The [sqlite3_log()] interface writes a message into the [error log]
+** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
+** ^If logging is enabled, the zFormat string and subsequent arguments are
+** used with [sqlite3_snprintf()] to generate the final output string.
+**
+** The sqlite3_log() interface is intended for use by extensions such as
+** virtual tables, collating functions, and SQL functions.  While there is
+** nothing to prevent an application from calling sqlite3_log(), doing so
+** is considered bad form.
+**
+** The zFormat string must not be NULL.
+**
+** To avoid deadlocks and other threading problems, the sqlite3_log() routine
+** will not use dynamically allocated memory.  The log message is stored in
+** a fixed-length buffer on the stack.  If the log message is longer than
+** a few hundred characters, it will be truncated to the length of the
+** buffer.
+*/
+SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
+
+/*
+** CAPI3REF: Write-Ahead Log Commit Hook
+** METHOD: sqlite3
+**
+** ^The [sqlite3_wal_hook()] function is used to register a callback that
+** is invoked each time data is committed to a database in wal mode.
+**
+** ^(The callback is invoked by SQLite after the commit has taken place and
+** the associated write-lock on the database released)^, so the implementation
+** may read, write or [checkpoint] the database as required.
+**
+** ^The first parameter passed to the callback function when it is invoked
+** is a copy of the third parameter passed to sqlite3_wal_hook() when
+** registering the callback. ^The second is a copy of the database handle.
+** ^The third parameter is the name of the database that was written to -
+** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
+** is the number of pages currently in the write-ahead log file,
+** including those that were just committed.
+**
+** The callback function should normally return [SQLITE_OK].  ^If an error
+** code is returned, that error will propagate back up through the
+** SQLite code base to cause the statement that provoked the callback
+** to report an error, though the commit will have still occurred. If the
+** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
+** that does not correspond to any valid SQLite error code, the results
+** are undefined.
+**
+** A single database handle may have at most a single write-ahead log callback
+** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
+** previously registered write-ahead log callback. ^The return value is
+** a copy of the third parameter from the previous call, if any, or 0.
+** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
+** overwrite any prior [sqlite3_wal_hook()] settings.
+*/
+SQLITE_API void *sqlite3_wal_hook(
+  sqlite3*,
+  int(*)(void *,sqlite3*,const char*,int),
+  void*
+);
+
+/*
+** CAPI3REF: Configure an auto-checkpoint
+** METHOD: sqlite3
+**
+** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
+** [sqlite3_wal_hook()] that causes any database on [database connection] D
+** to automatically [checkpoint]
+** after committing a transaction if there are N or
+** more frames in the [write-ahead log] file.  ^Passing zero or
+** a negative value as the nFrame parameter disables automatic
+** checkpoints entirely.
+**
+** ^The callback registered by this function replaces any existing callback
+** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
+** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
+** configured by this function.
+**
+** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
+** from SQL.
+**
+** ^Checkpoints initiated by this mechanism are
+** [sqlite3_wal_checkpoint_v2|PASSIVE].
+**
+** ^Every new [database connection] defaults to having the auto-checkpoint
+** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
+** pages.  The use of this interface
+** is only necessary if the default setting is found to be suboptimal
+** for a particular application.
+*/
+SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Checkpoint a database
+** METHOD: sqlite3
+**
+** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
+** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
+**
+** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
+** [write-ahead log] for database X on [database connection] D to be
+** transferred into the database file and for the write-ahead log to
+** be reset.  See the [checkpointing] documentation for addition
+** information.
+**
+** This interface used to be the only way to cause a checkpoint to
+** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
+** interface was added.  This interface is retained for backwards
+** compatibility and as a convenience for applications that need to manually
+** start a callback but which do not need the full power (and corresponding
+** complication) of [sqlite3_wal_checkpoint_v2()].
+*/
+SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Checkpoint a database
+** METHOD: sqlite3
+**
+** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
+** operation on database X of [database connection] D in mode M.  Status
+** information is written back into integers pointed to by L and C.)^
+** ^(The M parameter must be a valid [checkpoint mode]:)^
+**
+** <dl>
+** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
+**   ^Checkpoint as many frames as possible without waiting for any database
+**   readers or writers to finish, then sync the database file if all frames
+**   in the log were checkpointed. ^The [busy-handler callback]
+**   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
+**   ^On the other hand, passive mode might leave the checkpoint unfinished
+**   if there are concurrent readers or writers.
+**
+** <dt>SQLITE_CHECKPOINT_FULL<dd>
+**   ^This mode blocks (it invokes the
+**   [sqlite3_busy_handler|busy-handler callback]) until there is no
+**   database writer and all readers are reading from the most recent database
+**   snapshot. ^It then checkpoints all frames in the log file and syncs the
+**   database file. ^This mode blocks new database writers while it is pending,
+**   but new database readers are allowed to continue unimpeded.
+**
+** <dt>SQLITE_CHECKPOINT_RESTART<dd>
+**   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
+**   that after checkpointing the log file it blocks (calls the
+**   [busy-handler callback])
+**   until all readers are reading from the database file only. ^This ensures
+**   that the next writer will restart the log file from the beginning.
+**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
+**   database writer attempts while it is pending, but does not impede readers.
+**
+** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
+**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
+**   addition that it also truncates the log file to zero bytes just prior
+**   to a successful return.
+** </dl>
+**
+** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
+** the log file or to -1 if the checkpoint could not run because
+** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
+** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
+** log file (including any that were already checkpointed before the function
+** was called) or to -1 if the checkpoint could not run due to an error or
+** because the database is not in WAL mode. ^Note that upon successful
+** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
+** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
+**
+** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
+** any other process is running a checkpoint operation at the same time, the
+** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
+** busy-handler configured, it will not be invoked in this case.
+**
+** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
+** exclusive "writer" lock on the database file. ^If the writer lock cannot be
+** obtained immediately, and a busy-handler is configured, it is invoked and
+** the writer lock retried until either the busy-handler returns 0 or the lock
+** is successfully obtained. ^The busy-handler is also invoked while waiting for
+** database readers as described above. ^If the busy-handler returns 0 before
+** the writer lock is obtained or while waiting for database readers, the
+** checkpoint operation proceeds from that point in the same way as
+** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
+** without blocking any further. ^SQLITE_BUSY is returned in this case.
+**
+** ^If parameter zDb is NULL or points to a zero length string, then the
+** specified operation is attempted on all WAL databases [attached] to
+** [database connection] db.  In this case the
+** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
+** an SQLITE_BUSY error is encountered when processing one or more of the
+** attached WAL databases, the operation is still attempted on any remaining
+** attached databases and SQLITE_BUSY is returned at the end. ^If any other
+** error occurs while processing an attached database, processing is abandoned
+** and the error code is returned to the caller immediately. ^If no error
+** (SQLITE_BUSY or otherwise) is encountered while processing the attached
+** databases, SQLITE_OK is returned.
+**
+** ^If database zDb is the name of an attached database that is not in WAL
+** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
+** zDb is not NULL (or a zero length string) and is not the name of any
+** attached database, SQLITE_ERROR is returned to the caller.
+**
+** ^Unless it returns SQLITE_MISUSE,
+** the sqlite3_wal_checkpoint_v2() interface
+** sets the error information that is queried by
+** [sqlite3_errcode()] and [sqlite3_errmsg()].
+**
+** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
+** from SQL.
+*/
+SQLITE_API int sqlite3_wal_checkpoint_v2(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of attached database (or NULL) */
+  int eMode,                      /* SQLITE_CHECKPOINT_* value */
+  int *pnLog,                     /* OUT: Size of WAL log in frames */
+  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
+);
+
+/*
+** CAPI3REF: Checkpoint Mode Values
+** KEYWORDS: {checkpoint mode}
+**
+** These constants define all valid values for the "checkpoint mode" passed
+** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
+** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
+** meaning of each of these checkpoint modes.
+*/
+#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
+#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
+#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for readers */
+#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
+
+/*
+** CAPI3REF: Virtual Table Interface Configuration
+**
+** This function may be called by either the [xConnect] or [xCreate] method
+** of a [virtual table] implementation to configure
+** various facets of the virtual table interface.
+**
+** If this interface is invoked outside the context of an xConnect or
+** xCreate virtual table method then the behavior is undefined.
+**
+** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
+** [database connection] in which the virtual table is being created and
+** which is passed in as the first argument to the [xConnect] or [xCreate]
+** method that is invoking sqlite3_vtab_config().  The C parameter is one
+** of the [virtual table configuration options].  The presence and meaning
+** of parameters after C depend on which [virtual table configuration option]
+** is used.
+*/
+SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Virtual Table Configuration Options
+** KEYWORDS: {virtual table configuration options}
+** KEYWORDS: {virtual table configuration option}
+**
+** These macros define the various options to the
+** [sqlite3_vtab_config()] interface that [virtual table] implementations
+** can use to customize and optimize their behavior.
+**
+** <dl>
+** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
+** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
+** where X is an integer.  If X is zero, then the [virtual table] whose
+** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
+** support constraints.  In this configuration (which is the default) if
+** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
+** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
+** specified as part of the users SQL statement, regardless of the actual
+** ON CONFLICT mode specified.
+**
+** If X is non-zero, then the virtual table implementation guarantees
+** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
+** any modifications to internal or persistent data structures have been made.
+** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
+** is able to roll back a statement or database transaction, and abandon
+** or continue processing the current SQL statement as appropriate.
+** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
+** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
+** had been ABORT.
+**
+** Virtual table implementations that are required to handle OR REPLACE
+** must do so within the [xUpdate] method. If a call to the
+** [sqlite3_vtab_on_conflict()] function indicates that the current ON
+** CONFLICT policy is REPLACE, the virtual table implementation should
+** silently replace the appropriate rows within the xUpdate callback and
+** return SQLITE_OK. Or, if this is not possible, it may return
+** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
+** constraint handling.
+** </dd>
+**
+** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** prohibits that virtual table from being used from within triggers and
+** views.
+** </dd>
+**
+** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** identify that virtual table as being safe to use from within triggers
+** and views.  Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
+** virtual table can do no serious harm even if it is controlled by a
+** malicious hacker.  Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
+** flag unless absolutely necessary.
+** </dd>
+**
+** [[SQLITE_VTAB_USES_ALL_SCHEMAS]]<dt>SQLITE_VTAB_USES_ALL_SCHEMAS</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_USES_ALL_SCHEMA) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** instruct the query planner to begin at least a read transaction on
+** all schemas ("main", "temp", and any ATTACH-ed databases) whenever the
+** virtual table is used.
+** </dd>
+** </dl>
+*/
+#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
+#define SQLITE_VTAB_INNOCUOUS          2
+#define SQLITE_VTAB_DIRECTONLY         3
+#define SQLITE_VTAB_USES_ALL_SCHEMAS   4
+
+/*
+** CAPI3REF: Determine The Virtual Table Conflict Policy
+**
+** This function may only be called from within a call to the [xUpdate] method
+** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
+** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
+** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
+** of the SQL statement that triggered the call to the [xUpdate] method of the
+** [virtual table].
+*/
+SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
+
+/*
+** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
+**
+** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
+** method of a [virtual table], then it might return true if the
+** column is being fetched as part of an UPDATE operation during which the
+** column value will not change.  The virtual table implementation can use
+** this hint as permission to substitute a return value that is less
+** expensive to compute and that the corresponding
+** [xUpdate] method understands as a "no-change" value.
+**
+** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
+** the column is not changed by the UPDATE statement, then the xColumn
+** method can optionally return without setting a result, without calling
+** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
+** In that case, [sqlite3_value_nochange(X)] will return true for the
+** same column in the [xUpdate] method.
+**
+** The sqlite3_vtab_nochange() routine is an optimization.  Virtual table
+** implementations should continue to give a correct answer even if the
+** sqlite3_vtab_nochange() interface were to always return false.  In the
+** current implementation, the sqlite3_vtab_nochange() interface does always
+** returns false for the enhanced [UPDATE FROM] statement.
+*/
+SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
+
+/*
+** CAPI3REF: Determine The Collation For a Virtual Table Constraint
+** METHOD: sqlite3_index_info
+**
+** This function may only be called from within a call to the [xBestIndex]
+** method of a [virtual table].  This function returns a pointer to a string
+** that is the name of the appropriate collation sequence to use for text
+** comparisons on the constraint identified by its arguments.
+**
+** The first argument must be the pointer to the [sqlite3_index_info] object
+** that is the first parameter to the xBestIndex() method. The second argument
+** must be an index into the aConstraint[] array belonging to the
+** sqlite3_index_info structure passed to xBestIndex.
+**
+** Important:
+** The first parameter must be the same pointer that is passed into the
+** xBestMethod() method.  The first parameter may not be a pointer to a
+** different [sqlite3_index_info] object, even an exact copy.
+**
+** The return value is computed as follows:
+**
+** <ol>
+** <li><p> If the constraint comes from a WHERE clause expression that contains
+**         a [COLLATE operator], then the name of the collation specified by
+**         that COLLATE operator is returned.
+** <li><p> If there is no COLLATE operator, but the column that is the subject
+**         of the constraint specifies an alternative collating sequence via
+**         a [COLLATE clause] on the column definition within the CREATE TABLE
+**         statement that was passed into [sqlite3_declare_vtab()], then the
+**         name of that alternative collating sequence is returned.
+** <li><p> Otherwise, "BINARY" is returned.
+** </ol>
+*/
+SQLITE_API const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
+
+/*
+** CAPI3REF: Determine if a virtual table query is DISTINCT
+** METHOD: sqlite3_index_info
+**
+** This API may only be used from within an [xBestIndex|xBestIndex method]
+** of a [virtual table] implementation. The result of calling this
+** interface from outside of xBestIndex() is undefined and probably harmful.
+**
+** ^The sqlite3_vtab_distinct() interface returns an integer between 0 and
+** 3.  The integer returned by sqlite3_vtab_distinct()
+** gives the virtual table additional information about how the query
+** planner wants the output to be ordered. As long as the virtual table
+** can meet the ordering requirements of the query planner, it may set
+** the "orderByConsumed" flag.
+**
+** <ol><li value="0"><p>
+** ^If the sqlite3_vtab_distinct() interface returns 0, that means
+** that the query planner needs the virtual table to return all rows in the
+** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
+** [sqlite3_index_info] object.  This is the default expectation.  If the
+** virtual table outputs all rows in sorted order, then it is always safe for
+** the xBestIndex method to set the "orderByConsumed" flag, regardless of
+** the return value from sqlite3_vtab_distinct().
+** <li value="1"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
+** that the query planner does not need the rows to be returned in sorted order
+** as long as all rows with the same values in all columns identified by the
+** "aOrderBy" field are adjacent.)^  This mode is used when the query planner
+** is doing a GROUP BY.
+** <li value="2"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
+** that the query planner does not need the rows returned in any particular
+** order, as long as rows with the same values in all columns identified
+** by "aOrderBy" are adjacent.)^  ^(Furthermore, when two or more rows
+** contain the same values for all columns identified by "colUsed", all but
+** one such row may optionally be omitted from the result.)^
+** The virtual table is not required to omit rows that are duplicates
+** over the "colUsed" columns, but if the virtual table can do that without
+** too much extra effort, it could potentially help the query to run faster.
+** This mode is used for a DISTINCT query.
+** <li value="3"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 3, that means the
+** virtual table must return rows in the order defined by "aOrderBy" as
+** if the sqlite3_vtab_distinct() interface had returned 0.  However if
+** two or more rows in the result have the same values for all columns
+** identified by "colUsed", then all but one such row may optionally be
+** omitted.)^  Like when the return value is 2, the virtual table
+** is not required to omit rows that are duplicates over the "colUsed"
+** columns, but if the virtual table can do that without
+** too much extra effort, it could potentially help the query to run faster.
+** This mode is used for queries
+** that have both DISTINCT and ORDER BY clauses.
+** </ol>
+**
+** <p>The following table summarizes the conditions under which the
+** virtual table is allowed to set the "orderByConsumed" flag based on
+** the value returned by sqlite3_vtab_distinct().  This table is a
+** restatement of the previous four paragraphs:
+**
+** <table border=1 cellspacing=0 cellpadding=10 width="90%">
+** <tr>
+** <td valign="top">sqlite3_vtab_distinct() return value
+** <td valign="top">Rows are returned in aOrderBy order
+** <td valign="top">Rows with the same value in all aOrderBy columns are adjacent
+** <td valign="top">Duplicates over all colUsed columns may be omitted
+** <tr><td>0<td>yes<td>yes<td>no
+** <tr><td>1<td>no<td>yes<td>no
+** <tr><td>2<td>no<td>yes<td>yes
+** <tr><td>3<td>yes<td>yes<td>yes
+** </table>
+**
+** ^For the purposes of comparing virtual table output values to see if the
+** values are same value for sorting purposes, two NULL values are considered
+** to be the same.  In other words, the comparison operator is "IS"
+** (or "IS NOT DISTINCT FROM") and not "==".
+**
+** If a virtual table implementation is unable to meet the requirements
+** specified above, then it must not set the "orderByConsumed" flag in the
+** [sqlite3_index_info] object or an incorrect answer may result.
+**
+** ^A virtual table implementation is always free to return rows in any order
+** it wants, as long as the "orderByConsumed" flag is not set.  ^When the
+** the "orderByConsumed" flag is unset, the query planner will add extra
+** [bytecode] to ensure that the final results returned by the SQL query are
+** ordered correctly.  The use of the "orderByConsumed" flag and the
+** sqlite3_vtab_distinct() interface is merely an optimization.  ^Careful
+** use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
+** flag might help queries against a virtual table to run faster.  Being
+** overly aggressive and setting the "orderByConsumed" flag when it is not
+** valid to do so, on the other hand, might cause SQLite to return incorrect
+** results.
+*/
+SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info*);
+
+/*
+** CAPI3REF: Identify and handle IN constraints in xBestIndex
+**
+** This interface may only be used from within an
+** [xBestIndex|xBestIndex() method] of a [virtual table] implementation.
+** The result of invoking this interface from any other context is
+** undefined and probably harmful.
+**
+** ^(A constraint on a virtual table of the form
+** "[IN operator|column IN (...)]" is
+** communicated to the xBestIndex method as a
+** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^  If xBestIndex wants to use
+** this constraint, it must set the corresponding
+** aConstraintUsage[].argvIndex to a positive integer.  ^(Then, under
+** the usual mode of handling IN operators, SQLite generates [bytecode]
+** that invokes the [xFilter|xFilter() method] once for each value
+** on the right-hand side of the IN operator.)^  Thus the virtual table
+** only sees a single value from the right-hand side of the IN operator
+** at a time.
+**
+** In some cases, however, it would be advantageous for the virtual
+** table to see all values on the right-hand of the IN operator all at
+** once.  The sqlite3_vtab_in() interfaces facilitates this in two ways:
+**
+** <ol>
+** <li><p>
+**   ^A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
+**   if and only if the [sqlite3_index_info|P->aConstraint][N] constraint
+**   is an [IN operator] that can be processed all at once.  ^In other words,
+**   sqlite3_vtab_in() with -1 in the third argument is a mechanism
+**   by which the virtual table can ask SQLite if all-at-once processing
+**   of the IN operator is even possible.
+**
+** <li><p>
+**   ^A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
+**   to SQLite that the virtual table does or does not want to process
+**   the IN operator all-at-once, respectively.  ^Thus when the third
+**   parameter (F) is non-negative, this interface is the mechanism by
+**   which the virtual table tells SQLite how it wants to process the
+**   IN operator.
+** </ol>
+**
+** ^The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
+** within the same xBestIndex method call.  ^For any given P,N pair,
+** the return value from sqlite3_vtab_in(P,N,F) will always be the same
+** within the same xBestIndex call.  ^If the interface returns true
+** (non-zero), that means that the constraint is an IN operator
+** that can be processed all-at-once.  ^If the constraint is not an IN
+** operator or cannot be processed all-at-once, then the interface returns
+** false.
+**
+** ^(All-at-once processing of the IN operator is selected if both of the
+** following conditions are met:
+**
+** <ol>
+** <li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
+** integer.  This is how the virtual table tells SQLite that it wants to
+** use the N-th constraint.
+**
+** <li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
+** non-negative had F>=1.
+** </ol>)^
+**
+** ^If either or both of the conditions above are false, then SQLite uses
+** the traditional one-at-a-time processing strategy for the IN constraint.
+** ^If both conditions are true, then the argvIndex-th parameter to the
+** xFilter method will be an [sqlite3_value] that appears to be NULL,
+** but which can be passed to [sqlite3_vtab_in_first()] and
+** [sqlite3_vtab_in_next()] to find all values on the right-hand side
+** of the IN constraint.
+*/
+SQLITE_API int sqlite3_vtab_in(sqlite3_index_info*, int iCons, int bHandle);
+
+/*
+** CAPI3REF: Find all elements on the right-hand side of an IN constraint.
+**
+** These interfaces are only useful from within the
+** [xFilter|xFilter() method] of a [virtual table] implementation.
+** The result of invoking these interfaces from any other context
+** is undefined and probably harmful.
+**
+** The X parameter in a call to sqlite3_vtab_in_first(X,P) or
+** sqlite3_vtab_in_next(X,P) should be one of the parameters to the
+** xFilter method which invokes these routines, and specifically
+** a parameter that was previously selected for all-at-once IN constraint
+** processing use the [sqlite3_vtab_in()] interface in the
+** [xBestIndex|xBestIndex method].  ^(If the X parameter is not
+** an xFilter argument that was selected for all-at-once IN constraint
+** processing, then these routines return [SQLITE_ERROR].)^
+**
+** ^(Use these routines to access all values on the right-hand side
+** of the IN constraint using code like the following:
+**
+** <blockquote><pre>
+**    for(rc=sqlite3_vtab_in_first(pList, &pVal);
+**        rc==SQLITE_OK && pVal;
+**        rc=sqlite3_vtab_in_next(pList, &pVal)
+**    ){
+**      // do something with pVal
+**    }
+**    if( rc!=SQLITE_OK ){
+**      // an error has occurred
+**    }
+** </pre></blockquote>)^
+**
+** ^On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
+** routines return SQLITE_OK and set *P to point to the first or next value
+** on the RHS of the IN constraint.  ^If there are no more values on the
+** right hand side of the IN constraint, then *P is set to NULL and these
+** routines return [SQLITE_DONE].  ^The return value might be
+** some other value, such as SQLITE_NOMEM, in the event of a malfunction.
+**
+** The *ppOut values returned by these routines are only valid until the
+** next call to either of these routines or until the end of the xFilter
+** method from which these routines were called.  If the virtual table
+** implementation needs to retain the *ppOut values for longer, it must make
+** copies.  The *ppOut values are [protected sqlite3_value|protected].
+*/
+SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut);
+SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut);
+
+/*
+** CAPI3REF: Constraint values in xBestIndex()
+** METHOD: sqlite3_index_info
+**
+** This API may only be used from within the [xBestIndex|xBestIndex method]
+** of a [virtual table] implementation. The result of calling this interface
+** from outside of an xBestIndex method are undefined and probably harmful.
+**
+** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
+** the [xBestIndex] method of a [virtual table] implementation, with P being
+** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
+** J being a 0-based index into P->aConstraint[], then this routine
+** attempts to set *V to the value of the right-hand operand of
+** that constraint if the right-hand operand is known.  ^If the
+** right-hand operand is not known, then *V is set to a NULL pointer.
+** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
+** and only if *V is set to a value.  ^The sqlite3_vtab_rhs_value(P,J,V)
+** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
+** constraint is not available.  ^The sqlite3_vtab_rhs_value() interface
+** can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
+** something goes wrong.
+**
+** The sqlite3_vtab_rhs_value() interface is usually only successful if
+** the right-hand operand of a constraint is a literal value in the original
+** SQL statement.  If the right-hand operand is an expression or a reference
+** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
+** will probably return [SQLITE_NOTFOUND].
+**
+** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
+** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand.  For such
+** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
+**
+** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
+** and remains valid for the duration of the xBestIndex method call.
+** ^When xBestIndex returns, the sqlite3_value object returned by
+** sqlite3_vtab_rhs_value() is automatically deallocated.
+**
+** The "_rhs_" in the name of this routine is an abbreviation for
+** "Right-Hand Side".
+*/
+SQLITE_API int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);
+
+/*
+** CAPI3REF: Conflict resolution modes
+** KEYWORDS: {conflict resolution mode}
+**
+** These constants are returned by [sqlite3_vtab_on_conflict()] to
+** inform a [virtual table] implementation what the [ON CONFLICT] mode
+** is for the SQL statement being evaluated.
+**
+** Note that the [SQLITE_IGNORE] constant is also used as a potential
+** return value from the [sqlite3_set_authorizer()] callback and that
+** [SQLITE_ABORT] is also a [result code].
+*/
+#define SQLITE_ROLLBACK 1
+/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
+#define SQLITE_FAIL     3
+/* #define SQLITE_ABORT 4  // Also an error code */
+#define SQLITE_REPLACE  5
+
+/*
+** CAPI3REF: Prepared Statement Scan Status Opcodes
+** KEYWORDS: {scanstatus options}
+**
+** The following constants can be used for the T parameter to the
+** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
+** different metric for sqlite3_stmt_scanstatus() to return.
+**
+** When the value returned to V is a string, space to hold that string is
+** managed by the prepared statement S and will be automatically freed when
+** S is finalized.
+**
+** Not all values are available for all query elements. When a value is
+** not available, the output variable is set to -1 if the value is numeric,
+** or to NULL if it is a string (SQLITE_SCANSTAT_NAME).
+**
+** <dl>
+** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
+** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
+** set to the total number of times that the X-th loop has run.</dd>
+**
+** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
+** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
+** to the total number of rows examined by all iterations of the X-th loop.</dd>
+**
+** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
+** <dd>^The "double" variable pointed to by the V parameter will be set to the
+** query planner's estimate for the average number of rows output from each
+** iteration of the X-th loop.  If the query planner's estimates was accurate,
+** then this value will approximate the quotient NVISIT/NLOOP and the
+** product of this value for all prior loops with the same SELECTID will
+** be the NLOOP value for the current loop.
+**
+** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
+** <dd>^The "const char *" variable pointed to by the V parameter will be set
+** to a zero-terminated UTF-8 string containing the name of the index or table
+** used for the X-th loop.
+**
+** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
+** <dd>^The "const char *" variable pointed to by the V parameter will be set
+** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
+** description for the X-th loop.
+**
+** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECTID</dt>
+** <dd>^The "int" variable pointed to by the V parameter will be set to the
+** id for the X-th query plan element. The id value is unique within the
+** statement. The select-id is the same value as is output in the first
+** column of an [EXPLAIN QUERY PLAN] query.
+**
+** [[SQLITE_SCANSTAT_PARENTID]] <dt>SQLITE_SCANSTAT_PARENTID</dt>
+** <dd>The "int" variable pointed to by the V parameter will be set to the
+** the id of the parent of the current query element, if applicable, or
+** to zero if the query element has no parent. This is the same value as
+** returned in the second column of an [EXPLAIN QUERY PLAN] query.
+**
+** [[SQLITE_SCANSTAT_NCYCLE]] <dt>SQLITE_SCANSTAT_NCYCLE</dt>
+** <dd>The sqlite3_int64 output value is set to the number of cycles,
+** according to the processor time-stamp counter, that elapsed while the
+** query element was being processed. This value is not available for
+** all query elements - if it is unavailable the output variable is
+** set to -1.
+** </dl>
+*/
+#define SQLITE_SCANSTAT_NLOOP    0
+#define SQLITE_SCANSTAT_NVISIT   1
+#define SQLITE_SCANSTAT_EST      2
+#define SQLITE_SCANSTAT_NAME     3
+#define SQLITE_SCANSTAT_EXPLAIN  4
+#define SQLITE_SCANSTAT_SELECTID 5
+#define SQLITE_SCANSTAT_PARENTID 6
+#define SQLITE_SCANSTAT_NCYCLE   7
+
+/*
+** CAPI3REF: Prepared Statement Scan Status
+** METHOD: sqlite3_stmt
+**
+** These interfaces return information about the predicted and measured
+** performance for pStmt.  Advanced applications can use this
+** interface to compare the predicted and the measured performance and
+** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
+**
+** Since this interface is expected to be rarely used, it is only
+** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
+** compile-time option.
+**
+** The "iScanStatusOp" parameter determines which status information to return.
+** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
+** of this interface is undefined. ^The requested measurement is written into
+** a variable pointed to by the "pOut" parameter.
+**
+** The "flags" parameter must be passed a mask of flags. At present only
+** one flag is defined - SQLITE_SCANSTAT_COMPLEX. If SQLITE_SCANSTAT_COMPLEX
+** is specified, then status information is available for all elements
+** of a query plan that are reported by "EXPLAIN QUERY PLAN" output. If
+** SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
+** that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
+** the EXPLAIN QUERY PLAN output) are available. Invoking API
+** sqlite3_stmt_scanstatus() is equivalent to calling
+** sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.
+**
+** Parameter "idx" identifies the specific query element to retrieve statistics
+** for. Query elements are numbered starting from zero. A value of -1 may be
+** to query for statistics regarding the entire query. ^If idx is out of range
+** - less than -1 or greater than or equal to the total number of query
+** elements used to implement the statement - a non-zero value is returned and
+** the variable that pOut points to is unchanged.
+**
+** See also: [sqlite3_stmt_scanstatus_reset()]
+*/
+SQLITE_API int sqlite3_stmt_scanstatus(
+  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
+  int idx,                  /* Index of loop to report on */
+  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
+  void *pOut                /* Result written here */
+);
+SQLITE_API int sqlite3_stmt_scanstatus_v2(
+  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
+  int idx,                  /* Index of loop to report on */
+  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
+  int flags,                /* Mask of flags defined below */
+  void *pOut                /* Result written here */
+);
+
+/*
+** CAPI3REF: Prepared Statement Scan Status
+** KEYWORDS: {scan status flags}
+*/
+#define SQLITE_SCANSTAT_COMPLEX 0x0001
+
+/*
+** CAPI3REF: Zero Scan-Status Counters
+** METHOD: sqlite3_stmt
+**
+** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
+**
+** This API is only available if the library is built with pre-processor
+** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
+*/
+SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Flush caches to disk mid-transaction
+** METHOD: sqlite3
+**
+** ^If a write-transaction is open on [database connection] D when the
+** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
+** pages in the pager-cache that are not currently in use are written out
+** to disk. A dirty page may be in use if a database cursor created by an
+** active SQL statement is reading from it, or if it is page 1 of a database
+** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
+** interface flushes caches for all schemas - "main", "temp", and
+** any [attached] databases.
+**
+** ^If this function needs to obtain extra database locks before dirty pages
+** can be flushed to disk, it does so. ^If those locks cannot be obtained
+** immediately and there is a busy-handler callback configured, it is invoked
+** in the usual manner. ^If the required lock still cannot be obtained, then
+** the database is skipped and an attempt made to flush any dirty pages
+** belonging to the next (if any) database. ^If any databases are skipped
+** because locks cannot be obtained, but no other error occurs, this
+** function returns SQLITE_BUSY.
+**
+** ^If any other error occurs while flushing dirty pages to disk (for
+** example an IO error or out-of-memory condition), then processing is
+** abandoned and an SQLite [error code] is returned to the caller immediately.
+**
+** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
+**
+** ^This function does not set the database handle error code or message
+** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
+*/
+SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
+
+/*
+** CAPI3REF: The pre-update hook.
+** METHOD: sqlite3
+**
+** ^These interfaces are only available if SQLite is compiled using the
+** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
+**
+** ^The [sqlite3_preupdate_hook()] interface registers a callback function
+** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
+** on a database table.
+** ^At most one preupdate hook may be registered at a time on a single
+** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
+** the previous setting.
+** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
+** with a NULL pointer as the second parameter.
+** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
+** the first parameter to callbacks.
+**
+** ^The preupdate hook only fires for changes to real database tables; the
+** preupdate hook is not invoked for changes to [virtual tables] or to
+** system tables like sqlite_sequence or sqlite_stat1.
+**
+** ^The second parameter to the preupdate callback is a pointer to
+** the [database connection] that registered the preupdate hook.
+** ^The third parameter to the preupdate callback is one of the constants
+** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
+** kind of update operation that is about to occur.
+** ^(The fourth parameter to the preupdate callback is the name of the
+** database within the database connection that is being modified.  This
+** will be "main" for the main database or "temp" for TEMP tables or
+** the name given after the AS keyword in the [ATTACH] statement for attached
+** databases.)^
+** ^The fifth parameter to the preupdate callback is the name of the
+** table that is being modified.
+**
+** For an UPDATE or DELETE operation on a [rowid table], the sixth
+** parameter passed to the preupdate callback is the initial [rowid] of the
+** row being modified or deleted. For an INSERT operation on a rowid table,
+** or any operation on a WITHOUT ROWID table, the value of the sixth
+** parameter is undefined. For an INSERT or UPDATE on a rowid table the
+** seventh parameter is the final rowid value of the row being inserted
+** or updated. The value of the seventh parameter passed to the callback
+** function is not defined for operations on WITHOUT ROWID tables, or for
+** DELETE operations on rowid tables.
+**
+** ^The sqlite3_preupdate_hook(D,C,P) function returns the P argument from
+** the previous call on the same [database connection] D, or NULL for
+** the first call on D.
+**
+** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
+** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
+** provide additional information about a preupdate event. These routines
+** may only be called from within a preupdate callback.  Invoking any of
+** these routines from outside of a preupdate callback or with a
+** [database connection] pointer that is different from the one supplied
+** to the preupdate callback results in undefined and probably undesirable
+** behavior.
+**
+** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
+** in the row that is being inserted, updated, or deleted.
+**
+** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
+** a [protected sqlite3_value] that contains the value of the Nth column of
+** the table row before it is updated.  The N parameter must be between 0
+** and one less than the number of columns or the behavior will be
+** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
+** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
+** behavior is undefined.  The [sqlite3_value] that P points to
+** will be destroyed when the preupdate callback returns.
+**
+** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
+** a [protected sqlite3_value] that contains the value of the Nth column of
+** the table row after it is updated.  The N parameter must be between 0
+** and one less than the number of columns or the behavior will be
+** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
+** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
+** behavior is undefined.  The [sqlite3_value] that P points to
+** will be destroyed when the preupdate callback returns.
+**
+** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
+** callback was invoked as a result of a direct insert, update, or delete
+** operation; or 1 for inserts, updates, or deletes invoked by top-level
+** triggers; or 2 for changes resulting from triggers called by top-level
+** triggers; and so forth.
+**
+** When the [sqlite3_blob_write()] API is used to update a blob column,
+** the pre-update hook is invoked with SQLITE_DELETE. This is because the
+** in this case the new values are not available. In this case, when a
+** callback made with op==SQLITE_DELETE is actually a write using the
+** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
+** the index of the column being written. In other cases, where the
+** pre-update hook is being invoked for some other reason, including a
+** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
+**
+** See also:  [sqlite3_update_hook()]
+*/
+#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
+SQLITE_API void *sqlite3_preupdate_hook(
+  sqlite3 *db,
+  void(*xPreUpdate)(
+    void *pCtx,                   /* Copy of third arg to preupdate_hook() */
+    sqlite3 *db,                  /* Database handle */
+    int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
+    char const *zDb,              /* Database name */
+    char const *zName,            /* Table name */
+    sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
+    sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
+  ),
+  void*
+);
+SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
+SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
+SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
+SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
+SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *);
+#endif
+
+/*
+** CAPI3REF: Low-level system error code
+** METHOD: sqlite3
+**
+** ^Attempt to return the underlying operating system error code or error
+** number that caused the most recent I/O error or failure to open a file.
+** The return value is OS-dependent.  For example, on unix systems, after
+** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
+** called to get back the underlying "errno" that caused the problem, such
+** as ENOSPC, EAUTH, EISDIR, and so forth.
+*/
+SQLITE_API int sqlite3_system_errno(sqlite3*);
+
+/*
+** CAPI3REF: Database Snapshot
+** KEYWORDS: {snapshot} {sqlite3_snapshot}
+**
+** An instance of the snapshot object records the state of a [WAL mode]
+** database for some specific point in history.
+**
+** In [WAL mode], multiple [database connections] that are open on the
+** same database file can each be reading a different historical version
+** of the database file.  When a [database connection] begins a read
+** transaction, that connection sees an unchanging copy of the database
+** as it existed for the point in time when the transaction first started.
+** Subsequent changes to the database from other connections are not seen
+** by the reader until a new read transaction is started.
+**
+** The sqlite3_snapshot object records state information about an historical
+** version of the database file so that it is possible to later open a new read
+** transaction that sees that historical version of the database rather than
+** the most recent version.
+*/
+typedef struct sqlite3_snapshot {
+  unsigned char hidden[48];
+} sqlite3_snapshot;
+
+/*
+** CAPI3REF: Record A Database Snapshot
+** CONSTRUCTOR: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
+** new [sqlite3_snapshot] object that records the current state of
+** schema S in database connection D.  ^On success, the
+** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
+** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
+** If there is not already a read-transaction open on schema S when
+** this function is called, one is opened automatically.
+**
+** If a read-transaction is opened by this function, then it is guaranteed
+** that the returned snapshot object may not be invalidated by a database
+** writer or checkpointer until after the read-transaction is closed. This
+** is not guaranteed if a read-transaction is already open when this
+** function is called. In that case, any subsequent write or checkpoint
+** operation on the database may invalidate the returned snapshot handle,
+** even while the read-transaction remains open.
+**
+** The following must be true for this function to succeed. If any of
+** the following statements are false when sqlite3_snapshot_get() is
+** called, SQLITE_ERROR is returned. The final value of *P is undefined
+** in this case.
+**
+** <ul>
+**   <li> The database handle must not be in [autocommit mode].
+**
+**   <li> Schema S of [database connection] D must be a [WAL mode] database.
+**
+**   <li> There must not be a write transaction open on schema S of database
+**        connection D.
+**
+**   <li> One or more transactions must have been written to the current wal
+**        file since it was created on disk (by any connection). This means
+**        that a snapshot cannot be taken on a wal mode database with no wal
+**        file immediately after it is first opened. At least one transaction
+**        must be written to it first.
+** </ul>
+**
+** This function may also return SQLITE_NOMEM.  If it is called with the
+** database handle in autocommit mode but fails for some other reason,
+** whether or not a read transaction is opened on schema S is undefined.
+**
+** The [sqlite3_snapshot] object returned from a successful call to
+** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
+** to avoid a memory leak.
+**
+** The [sqlite3_snapshot_get()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
+  sqlite3 *db,
+  const char *zSchema,
+  sqlite3_snapshot **ppSnapshot
+);
+
+/*
+** CAPI3REF: Start a read transaction on an historical snapshot
+** METHOD: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
+** transaction or upgrades an existing one for schema S of
+** [database connection] D such that the read transaction refers to
+** historical [snapshot] P, rather than the most recent change to the
+** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
+** on success or an appropriate [error code] if it fails.
+**
+** ^In order to succeed, the database connection must not be in
+** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
+** is already a read transaction open on schema S, then the database handle
+** must have no active statements (SELECT statements that have been passed
+** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
+** SQLITE_ERROR is returned if either of these conditions is violated, or
+** if schema S does not exist, or if the snapshot object is invalid.
+**
+** ^A call to sqlite3_snapshot_open() will fail to open if the specified
+** snapshot has been overwritten by a [checkpoint]. In this case
+** SQLITE_ERROR_SNAPSHOT is returned.
+**
+** If there is already a read transaction open when this function is
+** invoked, then the same read transaction remains open (on the same
+** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
+** is returned. If another error code - for example SQLITE_PROTOCOL or an
+** SQLITE_IOERR error code - is returned, then the final state of the
+** read transaction is undefined. If SQLITE_OK is returned, then the
+** read transaction is now open on database snapshot P.
+**
+** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
+** database connection D does not know that the database file for
+** schema S is in [WAL mode].  A database connection might not know
+** that the database file is in [WAL mode] if there has been no prior
+** I/O on that database connection, or if the database entered [WAL mode]
+** after the most recent I/O on the database connection.)^
+** (Hint: Run "[PRAGMA application_id]" against a newly opened
+** database connection in order to make it ready to use snapshots.)
+**
+** The [sqlite3_snapshot_open()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
+  sqlite3 *db,
+  const char *zSchema,
+  sqlite3_snapshot *pSnapshot
+);
+
+/*
+** CAPI3REF: Destroy a snapshot
+** DESTRUCTOR: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
+** The application must eventually free every [sqlite3_snapshot] object
+** using this routine to avoid a memory leak.
+**
+** The [sqlite3_snapshot_free()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
+
+/*
+** CAPI3REF: Compare the ages of two snapshot handles.
+** METHOD: sqlite3_snapshot
+**
+** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
+** of two valid snapshot handles.
+**
+** If the two snapshot handles are not associated with the same database
+** file, the result of the comparison is undefined.
+**
+** Additionally, the result of the comparison is only valid if both of the
+** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
+** last time the wal file was deleted. The wal file is deleted when the
+** database is changed back to rollback mode or when the number of database
+** clients drops to zero. If either snapshot handle was obtained before the
+** wal file was last deleted, the value returned by this function
+** is undefined.
+**
+** Otherwise, this API returns a negative value if P1 refers to an older
+** snapshot than P2, zero if the two handles refer to the same database
+** snapshot, and a positive value if P1 is a newer snapshot than P2.
+**
+** This interface is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SNAPSHOT] option.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
+  sqlite3_snapshot *p1,
+  sqlite3_snapshot *p2
+);
+
+/*
+** CAPI3REF: Recover snapshots from a wal file
+** METHOD: sqlite3_snapshot
+**
+** If a [WAL file] remains on disk after all database connections close
+** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
+** or because the last process to have the database opened exited without
+** calling [sqlite3_close()]) and a new connection is subsequently opened
+** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
+** will only be able to open the last transaction added to the WAL file
+** even though the WAL file contains other valid transactions.
+**
+** This function attempts to scan the WAL file associated with database zDb
+** of database handle db and make all valid snapshots available to
+** sqlite3_snapshot_open(). It is an error if there is already a read
+** transaction open on the database, or if the database is not a WAL mode
+** database.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+**
+** This interface is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SNAPSHOT] option.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Serialize a database
+**
+** The sqlite3_serialize(D,S,P,F) interface returns a pointer to
+** memory that is a serialization of the S database on
+** [database connection] D.  If S is a NULL pointer, the main database is used.
+** If P is not a NULL pointer, then the size of the database in bytes
+** is written into *P.
+**
+** For an ordinary on-disk database file, the serialization is just a
+** copy of the disk file.  For an in-memory database or a "TEMP" database,
+** the serialization is the same sequence of bytes which would be written
+** to disk if that database where backed up to disk.
+**
+** The usual case is that sqlite3_serialize() copies the serialization of
+** the database into memory obtained from [sqlite3_malloc64()] and returns
+** a pointer to that memory.  The caller is responsible for freeing the
+** returned value to avoid a memory leak.  However, if the F argument
+** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
+** are made, and the sqlite3_serialize() function will return a pointer
+** to the contiguous memory representation of the database that SQLite
+** is currently using for that database, or NULL if the no such contiguous
+** memory representation of the database exists.  A contiguous memory
+** representation of the database will usually only exist if there has
+** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
+** values of D and S.
+** The size of the database is written into *P even if the
+** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
+** of the database exists.
+**
+** After the call, if the SQLITE_SERIALIZE_NOCOPY bit had been set,
+** the returned buffer content will remain accessible and unchanged
+** until either the next write operation on the connection or when
+** the connection is closed, and applications must not modify the
+** buffer. If the bit had been clear, the returned buffer will not
+** be accessed by SQLite after the call.
+**
+** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
+** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
+** allocation error occurs.
+**
+** This interface is omitted if SQLite is compiled with the
+** [SQLITE_OMIT_DESERIALIZE] option.
+*/
+SQLITE_API unsigned char *sqlite3_serialize(
+  sqlite3 *db,           /* The database connection */
+  const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
+  sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
+  unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3_serialize
+**
+** Zero or more of the following constants can be OR-ed together for
+** the F argument to [sqlite3_serialize(D,S,P,F)].
+**
+** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
+** a pointer to contiguous in-memory database that it is currently using,
+** without making a copy of the database.  If SQLite is not currently using
+** a contiguous in-memory database, then this option causes
+** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
+** using a contiguous in-memory database if it has been initialized by a
+** prior call to [sqlite3_deserialize()].
+*/
+#define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
+
+/*
+** CAPI3REF: Deserialize a database
+**
+** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
+** [database connection] D to disconnect from database S and then
+** reopen S as an in-memory database based on the serialization contained
+** in P.  The serialized database P is N bytes in size.  M is the size of
+** the buffer P, which might be larger than N.  If M is larger than N, and
+** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
+** permitted to add content to the in-memory database as long as the total
+** size does not exceed M bytes.
+**
+** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
+** invoke sqlite3_free() on the serialization buffer when the database
+** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
+** SQLite will try to increase the buffer size using sqlite3_realloc64()
+** if writes on the database cause it to grow larger than M bytes.
+**
+** Applications must not modify the buffer P or invalidate it before
+** the database connection D is closed.
+**
+** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
+** database is currently in a read transaction or is involved in a backup
+** operation.
+**
+** It is not possible to deserialized into the TEMP database.  If the
+** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
+** function returns SQLITE_ERROR.
+**
+** The deserialized database should not be in [WAL mode].  If the database
+** is in WAL mode, then any attempt to use the database file will result
+** in an [SQLITE_CANTOPEN] error.  The application can set the
+** [file format version numbers] (bytes 18 and 19) of the input database P
+** to 0x01 prior to invoking sqlite3_deserialize(D,S,P,N,M,F) to force the
+** database file into rollback mode and work around this limitation.
+**
+** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
+** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
+** [sqlite3_free()] is invoked on argument P prior to returning.
+**
+** This interface is omitted if SQLite is compiled with the
+** [SQLITE_OMIT_DESERIALIZE] option.
+*/
+SQLITE_API int sqlite3_deserialize(
+  sqlite3 *db,            /* The database connection */
+  const char *zSchema,    /* Which DB to reopen with the deserialization */
+  unsigned char *pData,   /* The serialized database content */
+  sqlite3_int64 szDb,     /* Number bytes in the deserialization */
+  sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
+  unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3_deserialize()
+**
+** The following are allowed values for 6th argument (the F argument) to
+** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
+**
+** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
+** in the P argument is held in memory obtained from [sqlite3_malloc64()]
+** and that SQLite should take ownership of this memory and automatically
+** free it when it has finished using it.  Without this flag, the caller
+** is responsible for freeing any dynamically allocated memory.
+**
+** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
+** grow the size of the database using calls to [sqlite3_realloc64()].  This
+** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
+** Without this flag, the deserialized database cannot increase in size beyond
+** the number of bytes specified by the M parameter.
+**
+** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
+** should be treated as read-only.
+*/
+#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
+#define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
+#define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
+
+/*
+** Undo the hack that converts floating point types to integer for
+** builds on processors without floating point support.
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# undef double
+#endif
+
+#if defined(__wasi__)
+# undef SQLITE_WASI
+# define SQLITE_WASI 1
+# ifndef SQLITE_OMIT_LOAD_EXTENSION
+#  define SQLITE_OMIT_LOAD_EXTENSION
+# endif
+# ifndef SQLITE_THREADSAFE
+#  define SQLITE_THREADSAFE 0
+# endif
+#endif
+
+#if 0
+}  /* End of the 'extern "C"' block */
+#endif
+/* #endif for SQLITE3_H will be added by mksqlite3.tcl */
+
+/******** Begin file sqlite3rtree.h *********/
+/*
+** 2010 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+
+#ifndef _SQLITE3RTREE_H_
+#define _SQLITE3RTREE_H_
+
+
+#if 0
+extern "C" {
+#endif
+
+typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
+typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
+
+/* The double-precision datatype used by RTree depends on the
+** SQLITE_RTREE_INT_ONLY compile-time option.
+*/
+#ifdef SQLITE_RTREE_INT_ONLY
+  typedef sqlite3_int64 sqlite3_rtree_dbl;
+#else
+  typedef double sqlite3_rtree_dbl;
+#endif
+
+/*
+** Register a geometry callback named zGeom that can be used as part of an
+** R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_geometry_callback(
+  sqlite3 *db,
+  const char *zGeom,
+  int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
+  void *pContext
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the first
+** argument to callbacks registered using rtree_geometry_callback().
+*/
+struct sqlite3_rtree_geometry {
+  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
+  int nParam;                     /* Size of array aParam[] */
+  sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
+  void *pUser;                    /* Callback implementation user data */
+  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
+};
+
+/*
+** Register a 2nd-generation geometry callback named zScore that can be
+** used as part of an R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_query_callback(
+  sqlite3 *db,
+  const char *zQueryFunc,
+  int (*xQueryFunc)(sqlite3_rtree_query_info*),
+  void *pContext,
+  void (*xDestructor)(void*)
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the
+** argument to scored geometry callback registered using
+** sqlite3_rtree_query_callback().
+**
+** Note that the first 5 fields of this structure are identical to
+** sqlite3_rtree_geometry.  This structure is a subclass of
+** sqlite3_rtree_geometry.
+*/
+struct sqlite3_rtree_query_info {
+  void *pContext;                   /* pContext from when function registered */
+  int nParam;                       /* Number of function parameters */
+  sqlite3_rtree_dbl *aParam;        /* value of function parameters */
+  void *pUser;                      /* callback can use this, if desired */
+  void (*xDelUser)(void*);          /* function to free pUser */
+  sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
+  unsigned int *anQueue;            /* Number of pending entries in the queue */
+  int nCoord;                       /* Number of coordinates */
+  int iLevel;                       /* Level of current node or entry */
+  int mxLevel;                      /* The largest iLevel value in the tree */
+  sqlite3_int64 iRowid;             /* Rowid for current entry */
+  sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
+  int eParentWithin;                /* Visibility of parent node */
+  int eWithin;                      /* OUT: Visibility */
+  sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
+  /* The following fields are only available in 3.8.11 and later */
+  sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
+};
+
+/*
+** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
+*/
+#define NOT_WITHIN       0   /* Object completely outside of query region */
+#define PARTLY_WITHIN    1   /* Object partially overlaps query region */
+#define FULLY_WITHIN     2   /* Object fully contained within query region */
+
+
+#if 0
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif  /* ifndef _SQLITE3RTREE_H_ */
+
+/******** End of sqlite3rtree.h *********/
+/******** Begin file sqlite3session.h *********/
+
+#if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
+#define __SQLITESESSION_H_ 1
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#if 0
+extern "C" {
+#endif
+
+
+/*
+** CAPI3REF: Session Object Handle
+**
+** An instance of this object is a [session] that can be used to
+** record changes to a database.
+*/
+typedef struct sqlite3_session sqlite3_session;
+
+/*
+** CAPI3REF: Changeset Iterator Handle
+**
+** An instance of this object acts as a cursor for iterating
+** over the elements of a [changeset] or [patchset].
+*/
+typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
+
+/*
+** CAPI3REF: Create A New Session Object
+** CONSTRUCTOR: sqlite3_session
+**
+** Create a new session object attached to database handle db. If successful,
+** a pointer to the new object is written to *ppSession and SQLITE_OK is
+** returned. If an error occurs, *ppSession is set to NULL and an SQLite
+** error code (e.g. SQLITE_NOMEM) is returned.
+**
+** It is possible to create multiple session objects attached to a single
+** database handle.
+**
+** Session objects created using this function should be deleted using the
+** [sqlite3session_delete()] function before the database handle that they
+** are attached to is itself closed. If the database handle is closed before
+** the session object is deleted, then the results of calling any session
+** module function, including [sqlite3session_delete()] on the session object
+** are undefined.
+**
+** Because the session module uses the [sqlite3_preupdate_hook()] API, it
+** is not possible for an application to register a pre-update hook on a
+** database handle that has one or more session objects attached. Nor is
+** it possible to create a session object attached to a database handle for
+** which a pre-update hook is already defined. The results of attempting
+** either of these things are undefined.
+**
+** The session object will be used to create changesets for tables in
+** database zDb, where zDb is either "main", or "temp", or the name of an
+** attached database. It is not an error if database zDb is not attached
+** to the database when the session object is created.
+*/
+SQLITE_API int sqlite3session_create(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of db (e.g. "main") */
+  sqlite3_session **ppSession     /* OUT: New session object */
+);
+
+/*
+** CAPI3REF: Delete A Session Object
+** DESTRUCTOR: sqlite3_session
+**
+** Delete a session object previously allocated using
+** [sqlite3session_create()]. Once a session object has been deleted, the
+** results of attempting to use pSession with any other session module
+** function are undefined.
+**
+** Session objects must be deleted before the database handle to which they
+** are attached is closed. Refer to the documentation for
+** [sqlite3session_create()] for details.
+*/
+SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Configure a Session Object
+** METHOD: sqlite3_session
+**
+** This method is used to configure a session object after it has been
+** created. At present the only valid values for the second parameter are
+** [SQLITE_SESSION_OBJCONFIG_SIZE] and [SQLITE_SESSION_OBJCONFIG_ROWID].
+**
+*/
+SQLITE_API int sqlite3session_object_config(sqlite3_session*, int op, void *pArg);
+
+/*
+** CAPI3REF: Options for sqlite3session_object_config
+**
+** The following values may passed as the the 2nd parameter to
+** sqlite3session_object_config().
+**
+** <dt>SQLITE_SESSION_OBJCONFIG_SIZE <dd>
+**   This option is used to set, clear or query the flag that enables
+**   the [sqlite3session_changeset_size()] API. Because it imposes some
+**   computational overhead, this API is disabled by default. Argument
+**   pArg must point to a value of type (int). If the value is initially
+**   0, then the sqlite3session_changeset_size() API is disabled. If it
+**   is greater than 0, then the same API is enabled. Or, if the initial
+**   value is less than zero, no change is made. In all cases the (int)
+**   variable is set to 1 if the sqlite3session_changeset_size() API is
+**   enabled following the current call, or 0 otherwise.
+**
+**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
+**   the first table has been attached to the session object.
+**
+** <dt>SQLITE_SESSION_OBJCONFIG_ROWID <dd>
+**   This option is used to set, clear or query the flag that enables
+**   collection of data for tables with no explicit PRIMARY KEY.
+**
+**   Normally, tables with no explicit PRIMARY KEY are simply ignored
+**   by the sessions module. However, if this flag is set, it behaves
+**   as if such tables have a column "_rowid_ INTEGER PRIMARY KEY" inserted
+**   as their leftmost columns.
+**
+**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
+**   the first table has been attached to the session object.
+*/
+#define SQLITE_SESSION_OBJCONFIG_SIZE  1
+#define SQLITE_SESSION_OBJCONFIG_ROWID 2
+
+/*
+** CAPI3REF: Enable Or Disable A Session Object
+** METHOD: sqlite3_session
+**
+** Enable or disable the recording of changes by a session object. When
+** enabled, a session object records changes made to the database. When
+** disabled - it does not. A newly created session object is enabled.
+** Refer to the documentation for [sqlite3session_changeset()] for further
+** details regarding how enabling and disabling a session object affects
+** the eventual changesets.
+**
+** Passing zero to this function disables the session. Passing a value
+** greater than zero enables it. Passing a value less than zero is a
+** no-op, and may be used to query the current state of the session.
+**
+** The return value indicates the final state of the session object: 0 if
+** the session is disabled, or 1 if it is enabled.
+*/
+SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
+
+/*
+** CAPI3REF: Set Or Clear the Indirect Change Flag
+** METHOD: sqlite3_session
+**
+** Each change recorded by a session object is marked as either direct or
+** indirect. A change is marked as indirect if either:
+**
+** <ul>
+**   <li> The session object "indirect" flag is set when the change is
+**        made, or
+**   <li> The change is made by an SQL trigger or foreign key action
+**        instead of directly as a result of a users SQL statement.
+** </ul>
+**
+** If a single row is affected by more than one operation within a session,
+** then the change is considered indirect if all operations meet the criteria
+** for an indirect change above, or direct otherwise.
+**
+** This function is used to set, clear or query the session object indirect
+** flag.  If the second argument passed to this function is zero, then the
+** indirect flag is cleared. If it is greater than zero, the indirect flag
+** is set. Passing a value less than zero does not modify the current value
+** of the indirect flag, and may be used to query the current state of the
+** indirect flag for the specified session object.
+**
+** The return value indicates the final state of the indirect flag: 0 if
+** it is clear, or 1 if it is set.
+*/
+SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
+
+/*
+** CAPI3REF: Attach A Table To A Session Object
+** METHOD: sqlite3_session
+**
+** If argument zTab is not NULL, then it is the name of a table to attach
+** to the session object passed as the first argument. All subsequent changes
+** made to the table while the session object is enabled will be recorded. See
+** documentation for [sqlite3session_changeset()] for further details.
+**
+** Or, if argument zTab is NULL, then changes are recorded for all tables
+** in the database. If additional tables are added to the database (by
+** executing "CREATE TABLE" statements) after this call is made, changes for
+** the new tables are also recorded.
+**
+** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
+** defined as part of their CREATE TABLE statement. It does not matter if the
+** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
+** KEY may consist of a single column, or may be a composite key.
+**
+** It is not an error if the named table does not exist in the database. Nor
+** is it an error if the named table does not have a PRIMARY KEY. However,
+** no changes will be recorded in either of these scenarios.
+**
+** Changes are not recorded for individual rows that have NULL values stored
+** in one or more of their PRIMARY KEY columns.
+**
+** SQLITE_OK is returned if the call completes without error. Or, if an error
+** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
+**
+** <h3>Special sqlite_stat1 Handling</h3>
+**
+** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
+** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
+**  <pre>
+**        CREATE TABLE sqlite_stat1(tbl,idx,stat)
+**  </pre>
+**
+** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
+** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
+** are recorded for rows for which (idx IS NULL) is true. However, for such
+** rows a zero-length blob (SQL value X'') is stored in the changeset or
+** patchset instead of a NULL value. This allows such changesets to be
+** manipulated by legacy implementations of sqlite3changeset_invert(),
+** concat() and similar.
+**
+** The sqlite3changeset_apply() function automatically converts the
+** zero-length blob back to a NULL value when updating the sqlite_stat1
+** table. However, if the application calls sqlite3changeset_new(),
+** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
+** iterator directly (including on a changeset iterator passed to a
+** conflict-handler callback) then the X'' value is returned. The application
+** must translate X'' to NULL itself if required.
+**
+** Legacy (older than 3.22.0) versions of the sessions module cannot capture
+** changes made to the sqlite_stat1 table. Legacy versions of the
+** sqlite3changeset_apply() function silently ignore any modifications to the
+** sqlite_stat1 table that are part of a changeset or patchset.
+*/
+SQLITE_API int sqlite3session_attach(
+  sqlite3_session *pSession,      /* Session object */
+  const char *zTab                /* Table name */
+);
+
+/*
+** CAPI3REF: Set a table filter on a Session Object.
+** METHOD: sqlite3_session
+**
+** The second argument (xFilter) is the "filter callback". For changes to rows
+** in tables that are not attached to the Session object, the filter is called
+** to determine whether changes to the table's rows should be tracked or not.
+** If xFilter returns 0, changes are not tracked. Note that once a table is
+** attached, xFilter will not be called again.
+*/
+SQLITE_API void sqlite3session_table_filter(
+  sqlite3_session *pSession,      /* Session object */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of third arg to _filter_table() */
+    const char *zTab              /* Table name */
+  ),
+  void *pCtx                      /* First argument passed to xFilter */
+);
+
+/*
+** CAPI3REF: Generate A Changeset From A Session Object
+** METHOD: sqlite3_session
+**
+** Obtain a changeset containing changes to the tables attached to the
+** session object passed as the first argument. If successful,
+** set *ppChangeset to point to a buffer containing the changeset
+** and *pnChangeset to the size of the changeset in bytes before returning
+** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
+** zero and return an SQLite error code.
+**
+** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
+** each representing a change to a single row of an attached table. An INSERT
+** change contains the values of each field of a new database row. A DELETE
+** contains the original values of each field of a deleted database row. An
+** UPDATE change contains the original values of each field of an updated
+** database row along with the updated values for each updated non-primary-key
+** column. It is not possible for an UPDATE change to represent a change that
+** modifies the values of primary key columns. If such a change is made, it
+** is represented in a changeset as a DELETE followed by an INSERT.
+**
+** Changes are not recorded for rows that have NULL values stored in one or
+** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
+** no corresponding change is present in the changesets returned by this
+** function. If an existing row with one or more NULL values stored in
+** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
+** only an INSERT is appears in the changeset. Similarly, if an existing row
+** with non-NULL PRIMARY KEY values is updated so that one or more of its
+** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
+** DELETE change only.
+**
+** The contents of a changeset may be traversed using an iterator created
+** using the [sqlite3changeset_start()] API. A changeset may be applied to
+** a database with a compatible schema using the [sqlite3changeset_apply()]
+** API.
+**
+** Within a changeset generated by this function, all changes related to a
+** single table are grouped together. In other words, when iterating through
+** a changeset or when applying a changeset to a database, all changes related
+** to a single table are processed before moving on to the next table. Tables
+** are sorted in the same order in which they were attached (or auto-attached)
+** to the sqlite3_session object. The order in which the changes related to
+** a single table are stored is undefined.
+**
+** Following a successful call to this function, it is the responsibility of
+** the caller to eventually free the buffer that *ppChangeset points to using
+** [sqlite3_free()].
+**
+** <h3>Changeset Generation</h3>
+**
+** Once a table has been attached to a session object, the session object
+** records the primary key values of all new rows inserted into the table.
+** It also records the original primary key and other column values of any
+** deleted or updated rows. For each unique primary key value, data is only
+** recorded once - the first time a row with said primary key is inserted,
+** updated or deleted in the lifetime of the session.
+**
+** There is one exception to the previous paragraph: when a row is inserted,
+** updated or deleted, if one or more of its primary key columns contain a
+** NULL value, no record of the change is made.
+**
+** The session object therefore accumulates two types of records - those
+** that consist of primary key values only (created when the user inserts
+** a new record) and those that consist of the primary key values and the
+** original values of other table columns (created when the users deletes
+** or updates a record).
+**
+** When this function is called, the requested changeset is created using
+** both the accumulated records and the current contents of the database
+** file. Specifically:
+**
+** <ul>
+**   <li> For each record generated by an insert, the database is queried
+**        for a row with a matching primary key. If one is found, an INSERT
+**        change is added to the changeset. If no such row is found, no change
+**        is added to the changeset.
+**
+**   <li> For each record generated by an update or delete, the database is
+**        queried for a row with a matching primary key. If such a row is
+**        found and one or more of the non-primary key fields have been
+**        modified from their original values, an UPDATE change is added to
+**        the changeset. Or, if no such row is found in the table, a DELETE
+**        change is added to the changeset. If there is a row with a matching
+**        primary key in the database, but all fields contain their original
+**        values, no change is added to the changeset.
+** </ul>
+**
+** This means, amongst other things, that if a row is inserted and then later
+** deleted while a session object is active, neither the insert nor the delete
+** will be present in the changeset. Or if a row is deleted and then later a
+** row with the same primary key values inserted while a session object is
+** active, the resulting changeset will contain an UPDATE change instead of
+** a DELETE and an INSERT.
+**
+** When a session object is disabled (see the [sqlite3session_enable()] API),
+** it does not accumulate records when rows are inserted, updated or deleted.
+** This may appear to have some counter-intuitive effects if a single row
+** is written to more than once during a session. For example, if a row
+** is inserted while a session object is enabled, then later deleted while
+** the same session object is disabled, no INSERT record will appear in the
+** changeset, even though the delete took place while the session was disabled.
+** Or, if one field of a row is updated while a session is disabled, and
+** another field of the same row is updated while the session is enabled, the
+** resulting changeset will contain an UPDATE change that updates both fields.
+*/
+SQLITE_API int sqlite3session_changeset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
+  void **ppChangeset              /* OUT: Buffer containing changeset */
+);
+
+/*
+** CAPI3REF: Return An Upper-limit For The Size Of The Changeset
+** METHOD: sqlite3_session
+**
+** By default, this function always returns 0. For it to return
+** a useful result, the sqlite3_session object must have been configured
+** to enable this API using sqlite3session_object_config() with the
+** SQLITE_SESSION_OBJCONFIG_SIZE verb.
+**
+** When enabled, this function returns an upper limit, in bytes, for the size
+** of the changeset that might be produced if sqlite3session_changeset() were
+** called. The final changeset size might be equal to or smaller than the
+** size in bytes returned by this function.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Load The Difference Between Tables Into A Session
+** METHOD: sqlite3_session
+**
+** If it is not already attached to the session object passed as the first
+** argument, this function attaches table zTbl in the same manner as the
+** [sqlite3session_attach()] function. If zTbl does not exist, or if it
+** does not have a primary key, this function is a no-op (but does not return
+** an error).
+**
+** Argument zFromDb must be the name of a database ("main", "temp" etc.)
+** attached to the same database handle as the session object that contains
+** a table compatible with the table attached to the session by this function.
+** A table is considered compatible if it:
+**
+** <ul>
+**   <li> Has the same name,
+**   <li> Has the same set of columns declared in the same order, and
+**   <li> Has the same PRIMARY KEY definition.
+** </ul>
+**
+** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
+** are compatible but do not have any PRIMARY KEY columns, it is not an error
+** but no changes are added to the session object. As with other session
+** APIs, tables without PRIMARY KEYs are simply ignored.
+**
+** This function adds a set of changes to the session object that could be
+** used to update the table in database zFrom (call this the "from-table")
+** so that its content is the same as the table attached to the session
+** object (call this the "to-table"). Specifically:
+**
+** <ul>
+**   <li> For each row (primary key) that exists in the to-table but not in
+**     the from-table, an INSERT record is added to the session object.
+**
+**   <li> For each row (primary key) that exists in the to-table but not in
+**     the from-table, a DELETE record is added to the session object.
+**
+**   <li> For each row (primary key) that exists in both tables, but features
+**     different non-PK values in each, an UPDATE record is added to the
+**     session.
+** </ul>
+**
+** To clarify, if this function is called and then a changeset constructed
+** using [sqlite3session_changeset()], then after applying that changeset to
+** database zFrom the contents of the two compatible tables would be
+** identical.
+**
+** It an error if database zFrom does not exist or does not contain the
+** required compatible table.
+**
+** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
+** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
+** may be set to point to a buffer containing an English language error
+** message. It is the responsibility of the caller to free this buffer using
+** sqlite3_free().
+*/
+SQLITE_API int sqlite3session_diff(
+  sqlite3_session *pSession,
+  const char *zFromDb,
+  const char *zTbl,
+  char **pzErrMsg
+);
+
+
+/*
+** CAPI3REF: Generate A Patchset From A Session Object
+** METHOD: sqlite3_session
+**
+** The differences between a patchset and a changeset are that:
+**
+** <ul>
+**   <li> DELETE records consist of the primary key fields only. The
+**        original values of other fields are omitted.
+**   <li> The original values of any modified fields are omitted from
+**        UPDATE records.
+** </ul>
+**
+** A patchset blob may be used with up to date versions of all
+** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
+** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
+** attempting to use a patchset blob with old versions of the
+** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
+**
+** Because the non-primary key "old.*" fields are omitted, no
+** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
+** is passed to the sqlite3changeset_apply() API. Other conflict types work
+** in the same way as for changesets.
+**
+** Changes within a patchset are ordered in the same way as for changesets
+** generated by the sqlite3session_changeset() function (i.e. all changes for
+** a single table are grouped together, tables appear in the order in which
+** they were attached to the session object).
+*/
+SQLITE_API int sqlite3session_patchset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
+  void **ppPatchset               /* OUT: Buffer containing patchset */
+);
+
+/*
+** CAPI3REF: Test if a changeset has recorded any changes.
+**
+** Return non-zero if no changes to attached tables have been recorded by
+** the session object passed as the first argument. Otherwise, if one or
+** more changes have been recorded, return zero.
+**
+** Even if this function returns zero, it is possible that calling
+** [sqlite3session_changeset()] on the session handle may still return a
+** changeset that contains no changes. This can happen when a row in
+** an attached table is modified and then later on the original values
+** are restored. However, if this function returns non-zero, then it is
+** guaranteed that a call to sqlite3session_changeset() will return a
+** changeset containing zero changes.
+*/
+SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Query for the amount of heap memory used by a session object.
+**
+** This API returns the total amount of heap memory in bytes currently
+** used by the session object passed as the only argument.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Create An Iterator To Traverse A Changeset
+** CONSTRUCTOR: sqlite3_changeset_iter
+**
+** Create an iterator used to iterate through the contents of a changeset.
+** If successful, *pp is set to point to the iterator handle and SQLITE_OK
+** is returned. Otherwise, if an error occurs, *pp is set to zero and an
+** SQLite error code is returned.
+**
+** The following functions can be used to advance and query a changeset
+** iterator created by this function:
+**
+** <ul>
+**   <li> [sqlite3changeset_next()]
+**   <li> [sqlite3changeset_op()]
+**   <li> [sqlite3changeset_new()]
+**   <li> [sqlite3changeset_old()]
+** </ul>
+**
+** It is the responsibility of the caller to eventually destroy the iterator
+** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
+** changeset (pChangeset) must remain valid until after the iterator is
+** destroyed.
+**
+** Assuming the changeset blob was created by one of the
+** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
+** [sqlite3changeset_invert()] functions, all changes within the changeset
+** that apply to a single table are grouped together. This means that when
+** an application iterates through a changeset using an iterator created by
+** this function, all changes that relate to a single table are visited
+** consecutively. There is no chance that the iterator will visit a change
+** the applies to table X, then one for table Y, and then later on visit
+** another change for table X.
+**
+** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
+** may be modified by passing a combination of
+** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
+**
+** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
+** and therefore subject to change.
+*/
+SQLITE_API int sqlite3changeset_start(
+  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
+  int nChangeset,                 /* Size of changeset blob in bytes */
+  void *pChangeset                /* Pointer to blob containing changeset */
+);
+SQLITE_API int sqlite3changeset_start_v2(
+  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
+  int nChangeset,                 /* Size of changeset blob in bytes */
+  void *pChangeset,               /* Pointer to blob containing changeset */
+  int flags                       /* SESSION_CHANGESETSTART_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3changeset_start_v2
+**
+** The following flags may passed via the 4th parameter to
+** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
+**
+** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
+**   Invert the changeset while iterating through it. This is equivalent to
+**   inverting a changeset using sqlite3changeset_invert() before applying it.
+**   It is an error to specify this flag with a patchset.
+*/
+#define SQLITE_CHANGESETSTART_INVERT        0x0002
+
+
+/*
+** CAPI3REF: Advance A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function may only be used with iterators created by the function
+** [sqlite3changeset_start()]. If it is called on an iterator passed to
+** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
+** is returned and the call has no effect.
+**
+** Immediately after an iterator is created by sqlite3changeset_start(), it
+** does not point to any change in the changeset. Assuming the changeset
+** is not empty, the first call to this function advances the iterator to
+** point to the first change in the changeset. Each subsequent call advances
+** the iterator to point to the next change in the changeset (if any). If
+** no error occurs and the iterator points to a valid change after a call
+** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
+** Otherwise, if all changes in the changeset have already been visited,
+** SQLITE_DONE is returned.
+**
+** If an error occurs, an SQLite error code is returned. Possible error
+** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
+** SQLITE_NOMEM.
+*/
+SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
+
+/*
+** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
+** is not the case, this function returns [SQLITE_MISUSE].
+**
+** Arguments pOp, pnCol and pzTab may not be NULL. Upon return, three
+** outputs are set through these pointers:
+**
+** *pOp is set to one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
+** depending on the type of change that the iterator currently points to;
+**
+** *pnCol is set to the number of columns in the table affected by the change; and
+**
+** *pzTab is set to point to a nul-terminated utf-8 encoded string containing
+** the name of the table affected by the current change. The buffer remains
+** valid until either sqlite3changeset_next() is called on the iterator
+** or until the conflict-handler function returns.
+**
+** If pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
+** is an indirect change, or false (0) otherwise. See the documentation for
+** [sqlite3session_indirect()] for a description of direct and indirect
+** changes.
+**
+** If no error occurs, SQLITE_OK is returned. If an error does occur, an
+** SQLite error code is returned. The values of the output variables may not
+** be trusted in this case.
+*/
+SQLITE_API int sqlite3changeset_op(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  const char **pzTab,             /* OUT: Pointer to table name */
+  int *pnCol,                     /* OUT: Number of columns in table */
+  int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
+  int *pbIndirect                 /* OUT: True for an 'indirect' change */
+);
+
+/*
+** CAPI3REF: Obtain The Primary Key Definition Of A Table
+** METHOD: sqlite3_changeset_iter
+**
+** For each modified table, a changeset includes the following:
+**
+** <ul>
+**   <li> The number of columns in the table, and
+**   <li> Which of those columns make up the tables PRIMARY KEY.
+** </ul>
+**
+** This function is used to find which columns comprise the PRIMARY KEY of
+** the table modified by the change that iterator pIter currently points to.
+** If successful, *pabPK is set to point to an array of nCol entries, where
+** nCol is the number of columns in the table. Elements of *pabPK are set to
+** 0x01 if the corresponding column is part of the tables primary key, or
+** 0x00 if it is not.
+**
+** If argument pnCol is not NULL, then *pnCol is set to the number of columns
+** in the table.
+**
+** If this function is called when the iterator does not point to a valid
+** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
+** SQLITE_OK is returned and the output variables populated as described
+** above.
+*/
+SQLITE_API int sqlite3changeset_pk(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
+  int *pnCol                      /* OUT: Number of entries in output array */
+);
+
+/*
+** CAPI3REF: Obtain old.* Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
+** Furthermore, it may only be called if the type of change that the iterator
+** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
+** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the vector of
+** original row values stored as part of the UPDATE or DELETE change and
+** returns SQLITE_OK. The name of the function comes from the fact that this
+** is similar to the "old.*" columns available to update or delete triggers.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_old(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
+);
+
+/*
+** CAPI3REF: Obtain new.* Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
+** Furthermore, it may only be called if the type of change that the iterator
+** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
+** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the vector of
+** new row values stored as part of the UPDATE or INSERT change and
+** returns SQLITE_OK. If the change is an UPDATE and does not include
+** a new value for the requested column, *ppValue is set to NULL and
+** SQLITE_OK returned. The name of the function comes from the fact that
+** this is similar to the "new.*" columns available to update or delete
+** triggers.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_new(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
+);
+
+/*
+** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function should only be used with iterator objects passed to a
+** conflict-handler callback by [sqlite3changeset_apply()] with either
+** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
+** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
+** is set to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the
+** "conflicting row" associated with the current conflict-handler callback
+** and returns SQLITE_OK.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_conflict(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: Value from conflicting row */
+);
+
+/*
+** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
+** METHOD: sqlite3_changeset_iter
+**
+** This function may only be called with an iterator passed to an
+** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
+** it sets the output variable to the total number of known foreign key
+** violations in the destination database and returns SQLITE_OK.
+**
+** In all other cases this function returns SQLITE_MISUSE.
+*/
+SQLITE_API int sqlite3changeset_fk_conflicts(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int *pnOut                      /* OUT: Number of FK violations */
+);
+
+
+/*
+** CAPI3REF: Finalize A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function is used to finalize an iterator allocated with
+** [sqlite3changeset_start()].
+**
+** This function should only be called on iterators created using the
+** [sqlite3changeset_start()] function. If an application calls this
+** function with an iterator passed to a conflict-handler by
+** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
+** call has no effect.
+**
+** If an error was encountered within a call to an sqlite3changeset_xxx()
+** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
+** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
+** to that error is returned by this function. Otherwise, SQLITE_OK is
+** returned. This is to allow the following pattern (pseudo-code):
+**
+** <pre>
+**   sqlite3changeset_start();
+**   while( SQLITE_ROW==sqlite3changeset_next() ){
+**     // Do something with change.
+**   }
+**   rc = sqlite3changeset_finalize();
+**   if( rc!=SQLITE_OK ){
+**     // An error has occurred
+**   }
+** </pre>
+*/
+SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
+
+/*
+** CAPI3REF: Invert A Changeset
+**
+** This function is used to "invert" a changeset object. Applying an inverted
+** changeset to a database reverses the effects of applying the uninverted
+** changeset. Specifically:
+**
+** <ul>
+**   <li> Each DELETE change is changed to an INSERT, and
+**   <li> Each INSERT change is changed to a DELETE, and
+**   <li> For each UPDATE change, the old.* and new.* values are exchanged.
+** </ul>
+**
+** This function does not change the order in which changes appear within
+** the changeset. It merely reverses the sense of each individual change.
+**
+** If successful, a pointer to a buffer containing the inverted changeset
+** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
+** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
+** zeroed and an SQLite error code returned.
+**
+** It is the responsibility of the caller to eventually call sqlite3_free()
+** on the *ppOut pointer to free the buffer allocation following a successful
+** call to this function.
+**
+** WARNING/TODO: This function currently assumes that the input is a valid
+** changeset. If it is not, the results are undefined.
+*/
+SQLITE_API int sqlite3changeset_invert(
+  int nIn, const void *pIn,       /* Input changeset */
+  int *pnOut, void **ppOut        /* OUT: Inverse of input */
+);
+
+/*
+** CAPI3REF: Concatenate Two Changeset Objects
+**
+** This function is used to concatenate two changesets, A and B, into a
+** single changeset. The result is a changeset equivalent to applying
+** changeset A followed by changeset B.
+**
+** This function combines the two input changesets using an
+** sqlite3_changegroup object. Calling it produces similar results as the
+** following code fragment:
+**
+** <pre>
+**   sqlite3_changegroup *pGrp;
+**   rc = sqlite3_changegroup_new(&pGrp);
+**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
+**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
+**   if( rc==SQLITE_OK ){
+**     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
+**   }else{
+**     *ppOut = 0;
+**     *pnOut = 0;
+**   }
+** </pre>
+**
+** Refer to the sqlite3_changegroup documentation below for details.
+*/
+SQLITE_API int sqlite3changeset_concat(
+  int nA,                         /* Number of bytes in buffer pA */
+  void *pA,                       /* Pointer to buffer containing changeset A */
+  int nB,                         /* Number of bytes in buffer pB */
+  void *pB,                       /* Pointer to buffer containing changeset B */
+  int *pnOut,                     /* OUT: Number of bytes in output changeset */
+  void **ppOut                    /* OUT: Buffer containing output changeset */
+);
+
+
+/*
+** CAPI3REF: Upgrade the Schema of a Changeset/Patchset
+*/
+SQLITE_API int sqlite3changeset_upgrade(
+  sqlite3 *db,
+  const char *zDb,
+  int nIn, const void *pIn,       /* Input changeset */
+  int *pnOut, void **ppOut        /* OUT: Inverse of input */
+);
+
+
+
+/*
+** CAPI3REF: Changegroup Handle
+**
+** A changegroup is an object used to combine two or more
+** [changesets] or [patchsets]
+*/
+typedef struct sqlite3_changegroup sqlite3_changegroup;
+
+/*
+** CAPI3REF: Create A New Changegroup Object
+** CONSTRUCTOR: sqlite3_changegroup
+**
+** An sqlite3_changegroup object is used to combine two or more changesets
+** (or patchsets) into a single changeset (or patchset). A single changegroup
+** object may combine changesets or patchsets, but not both. The output is
+** always in the same format as the input.
+**
+** If successful, this function returns SQLITE_OK and populates (*pp) with
+** a pointer to a new sqlite3_changegroup object before returning. The caller
+** should eventually free the returned object using a call to
+** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
+** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
+**
+** The usual usage pattern for an sqlite3_changegroup object is as follows:
+**
+** <ul>
+**   <li> It is created using a call to sqlite3changegroup_new().
+**
+**   <li> Zero or more changesets (or patchsets) are added to the object
+**        by calling sqlite3changegroup_add().
+**
+**   <li> The result of combining all input changesets together is obtained
+**        by the application via a call to sqlite3changegroup_output().
+**
+**   <li> The object is deleted using a call to sqlite3changegroup_delete().
+** </ul>
+**
+** Any number of calls to add() and output() may be made between the calls to
+** new() and delete(), and in any order.
+**
+** As well as the regular sqlite3changegroup_add() and
+** sqlite3changegroup_output() functions, also available are the streaming
+** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
+*/
+SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
+
+/*
+** CAPI3REF: Add a Schema to a Changegroup
+** METHOD: sqlite3_changegroup_schema
+**
+** This method may be used to optionally enforce the rule that the changesets
+** added to the changegroup handle must match the schema of database zDb
+** ("main", "temp", or the name of an attached database). If
+** sqlite3changegroup_add() is called to add a changeset that is not compatible
+** with the configured schema, SQLITE_SCHEMA is returned and the changegroup
+** object is left in an undefined state.
+**
+** A changeset schema is considered compatible with the database schema in
+** the same way as for sqlite3changeset_apply(). Specifically, for each
+** table in the changeset, there exists a database table with:
+**
+** <ul>
+**   <li> The name identified by the changeset, and
+**   <li> at least as many columns as recorded in the changeset, and
+**   <li> the primary key columns in the same position as recorded in
+**        the changeset.
+** </ul>
+**
+** The output of the changegroup object always has the same schema as the
+** database nominated using this function. In cases where changesets passed
+** to sqlite3changegroup_add() have fewer columns than the corresponding table
+** in the database schema, these are filled in using the default column
+** values from the database schema. This makes it possible to combined
+** changesets that have different numbers of columns for a single table
+** within a changegroup, provided that they are otherwise compatible.
+*/
+SQLITE_API int sqlite3changegroup_schema(sqlite3_changegroup*, sqlite3*, const char *zDb);
+
+/*
+** CAPI3REF: Add A Changeset To A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** Add all changes within the changeset (or patchset) in buffer pData (size
+** nData bytes) to the changegroup.
+**
+** If the buffer contains a patchset, then all prior calls to this function
+** on the same changegroup object must also have specified patchsets. Or, if
+** the buffer contains a changeset, so must have the earlier calls to this
+** function. Otherwise, SQLITE_ERROR is returned and no changes are added
+** to the changegroup.
+**
+** Rows within the changeset and changegroup are identified by the values in
+** their PRIMARY KEY columns. A change in the changeset is considered to
+** apply to the same row as a change already present in the changegroup if
+** the two rows have the same primary key.
+**
+** Changes to rows that do not already appear in the changegroup are
+** simply copied into it. Or, if both the new changeset and the changegroup
+** contain changes that apply to a single row, the final contents of the
+** changegroup depends on the type of each change, as follows:
+**
+** <table border=1 style="margin-left:8ex;margin-right:8ex">
+**   <tr><th style="white-space:pre">Existing Change  </th>
+**       <th style="white-space:pre">New Change       </th>
+**       <th>Output Change
+**   <tr><td>INSERT <td>INSERT <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>INSERT <td>UPDATE <td>
+**       The INSERT change remains in the changegroup. The values in the
+**       INSERT change are modified as if the row was inserted by the
+**       existing change and then updated according to the new change.
+**   <tr><td>INSERT <td>DELETE <td>
+**       The existing INSERT is removed from the changegroup. The DELETE is
+**       not added.
+**   <tr><td>UPDATE <td>INSERT <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>UPDATE <td>UPDATE <td>
+**       The existing UPDATE remains within the changegroup. It is amended
+**       so that the accompanying values are as if the row was updated once
+**       by the existing change and then again by the new change.
+**   <tr><td>UPDATE <td>DELETE <td>
+**       The existing UPDATE is replaced by the new DELETE within the
+**       changegroup.
+**   <tr><td>DELETE <td>INSERT <td>
+**       If one or more of the column values in the row inserted by the
+**       new change differ from those in the row deleted by the existing
+**       change, the existing DELETE is replaced by an UPDATE within the
+**       changegroup. Otherwise, if the inserted row is exactly the same
+**       as the deleted row, the existing DELETE is simply discarded.
+**   <tr><td>DELETE <td>UPDATE <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>DELETE <td>DELETE <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+** </table>
+**
+** If the new changeset contains changes to a table that is already present
+** in the changegroup, then the number of columns and the position of the
+** primary key columns for the table must be consistent. If this is not the
+** case, this function fails with SQLITE_SCHEMA. Except, if the changegroup
+** object has been configured with a database schema using the
+** sqlite3changegroup_schema() API, then it is possible to combine changesets
+** with different numbers of columns for a single table, provided that
+** they are otherwise compatible.
+**
+** If the input changeset appears to be corrupt and the corruption is
+** detected, SQLITE_CORRUPT is returned. Or, if an out-of-memory condition
+** occurs during processing, this function returns SQLITE_NOMEM.
+**
+** In all cases, if an error occurs the state of the final contents of the
+** changegroup is undefined. If no error occurs, SQLITE_OK is returned.
+*/
+SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
+
+/*
+** CAPI3REF: Add A Single Change To A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** This function adds the single change currently indicated by the iterator
+** passed as the second argument to the changegroup object. The rules for
+** adding the change are just as described for [sqlite3changegroup_add()].
+**
+** If the change is successfully added to the changegroup, SQLITE_OK is
+** returned. Otherwise, an SQLite error code is returned.
+**
+** The iterator must point to a valid entry when this function is called.
+** If it does not, SQLITE_ERROR is returned and no change is added to the
+** changegroup. Additionally, the iterator must not have been opened with
+** the SQLITE_CHANGESETAPPLY_INVERT flag. In this case SQLITE_ERROR is also
+** returned.
+*/
+SQLITE_API int sqlite3changegroup_add_change(
+  sqlite3_changegroup*,
+  sqlite3_changeset_iter*
+);
+
+
+
+/*
+** CAPI3REF: Obtain A Composite Changeset From A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** Obtain a buffer containing a changeset (or patchset) representing the
+** current contents of the changegroup. If the inputs to the changegroup
+** were themselves changesets, the output is a changeset. Or, if the
+** inputs were patchsets, the output is also a patchset.
+**
+** As with the output of the sqlite3session_changeset() and
+** sqlite3session_patchset() functions, all changes related to a single
+** table are grouped together in the output of this function. Tables appear
+** in the same order as for the very first changeset added to the changegroup.
+** If the second or subsequent changesets added to the changegroup contain
+** changes for tables that do not appear in the first changeset, they are
+** appended onto the end of the output changeset, again in the order in
+** which they are first encountered.
+**
+** If an error occurs, an SQLite error code is returned and the output
+** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
+** is returned and the output variables are set to the size of and a
+** pointer to the output buffer, respectively. In this case it is the
+** responsibility of the caller to eventually free the buffer using a
+** call to sqlite3_free().
+*/
+SQLITE_API int sqlite3changegroup_output(
+  sqlite3_changegroup*,
+  int *pnData,                    /* OUT: Size of output buffer in bytes */
+  void **ppData                   /* OUT: Pointer to output buffer */
+);
+
+/*
+** CAPI3REF: Delete A Changegroup Object
+** DESTRUCTOR: sqlite3_changegroup
+*/
+SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
+
+/*
+** CAPI3REF: Apply A Changeset To A Database
+**
+** Apply a changeset or patchset to a database. These functions attempt to
+** update the "main" database attached to handle db with the changes found in
+** the changeset passed via the second and third arguments.
+**
+** The fourth argument (xFilter) passed to these functions is the "filter
+** callback". If it is not NULL, then for each table affected by at least one
+** change in the changeset, the filter callback is invoked with
+** the table name as the second argument, and a copy of the context pointer
+** passed as the sixth argument as the first. If the "filter callback"
+** returns zero, then no attempt is made to apply any changes to the table.
+** Otherwise, if the return value is non-zero or the xFilter argument to
+** is NULL, all changes related to the table are attempted.
+**
+** For each table that is not excluded by the filter callback, this function
+** tests that the target database contains a compatible table. A table is
+** considered compatible if all of the following are true:
+**
+** <ul>
+**   <li> The table has the same name as the name recorded in the
+**        changeset, and
+**   <li> The table has at least as many columns as recorded in the
+**        changeset, and
+**   <li> The table has primary key columns in the same position as
+**        recorded in the changeset.
+** </ul>
+**
+** If there is no compatible table, it is not an error, but none of the
+** changes associated with the table are applied. A warning message is issued
+** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
+** one such warning is issued for each table in the changeset.
+**
+** For each change for which there is a compatible table, an attempt is made
+** to modify the table contents according to the UPDATE, INSERT or DELETE
+** change. If a change cannot be applied cleanly, the conflict handler
+** function passed as the fifth argument to sqlite3changeset_apply() may be
+** invoked. A description of exactly when the conflict handler is invoked for
+** each type of change is below.
+**
+** Unlike the xFilter argument, xConflict may not be passed NULL. The results
+** of passing anything other than a valid function pointer as the xConflict
+** argument are undefined.
+**
+** Each time the conflict handler function is invoked, it must return one
+** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
+** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
+** if the second argument passed to the conflict handler is either
+** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
+** returns an illegal value, any changes already made are rolled back and
+** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
+** actions are taken by sqlite3changeset_apply() depending on the value
+** returned by each invocation of the conflict-handler function. Refer to
+** the documentation for the three
+** [SQLITE_CHANGESET_OMIT|available return values] for details.
+**
+** <dl>
+** <dt>DELETE Changes<dd>
+**   For each DELETE change, the function checks if the target database
+**   contains a row with the same primary key value (or values) as the
+**   original row values stored in the changeset. If it does, and the values
+**   stored in all non-primary key columns also match the values stored in
+**   the changeset the row is deleted from the target database.
+**
+**   If a row with matching primary key values is found, but one or more of
+**   the non-primary key fields contains a value different from the original
+**   row value stored in the changeset, the conflict-handler function is
+**   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
+**   database table has more columns than are recorded in the changeset,
+**   only the values of those non-primary key fields are compared against
+**   the current database contents - any trailing database table columns
+**   are ignored.
+**
+**   If no row with matching primary key values is found in the database,
+**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
+**   passed as the second argument.
+**
+**   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
+**   (which can only happen if a foreign key constraint is violated), the
+**   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
+**   passed as the second argument. This includes the case where the DELETE
+**   operation is attempted because an earlier call to the conflict handler
+**   function returned [SQLITE_CHANGESET_REPLACE].
+**
+** <dt>INSERT Changes<dd>
+**   For each INSERT change, an attempt is made to insert the new row into
+**   the database. If the changeset row contains fewer fields than the
+**   database table, the trailing fields are populated with their default
+**   values.
+**
+**   If the attempt to insert the row fails because the database already
+**   contains a row with the same primary key values, the conflict handler
+**   function is invoked with the second argument set to
+**   [SQLITE_CHANGESET_CONFLICT].
+**
+**   If the attempt to insert the row fails because of some other constraint
+**   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
+**   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
+**   This includes the case where the INSERT operation is re-attempted because
+**   an earlier call to the conflict handler function returned
+**   [SQLITE_CHANGESET_REPLACE].
+**
+** <dt>UPDATE Changes<dd>
+**   For each UPDATE change, the function checks if the target database
+**   contains a row with the same primary key value (or values) as the
+**   original row values stored in the changeset. If it does, and the values
+**   stored in all modified non-primary key columns also match the values
+**   stored in the changeset the row is updated within the target database.
+**
+**   If a row with matching primary key values is found, but one or more of
+**   the modified non-primary key fields contains a value different from an
+**   original row value stored in the changeset, the conflict-handler function
+**   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
+**   UPDATE changes only contain values for non-primary key fields that are
+**   to be modified, only those fields need to match the original values to
+**   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
+**
+**   If no row with matching primary key values is found in the database,
+**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
+**   passed as the second argument.
+**
+**   If the UPDATE operation is attempted, but SQLite returns
+**   SQLITE_CONSTRAINT, the conflict-handler function is invoked with
+**   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
+**   This includes the case where the UPDATE operation is attempted after
+**   an earlier call to the conflict handler function returned
+**   [SQLITE_CHANGESET_REPLACE].
+** </dl>
+**
+** It is safe to execute SQL statements, including those that write to the
+** table that the callback related to, from within the xConflict callback.
+** This can be used to further customize the application's conflict
+** resolution strategy.
+**
+** All changes made by these functions are enclosed in a savepoint transaction.
+** If any other error (aside from a constraint failure when attempting to
+** write to the target database) occurs, then the savepoint transaction is
+** rolled back, restoring the target database to its original state, and an
+** SQLite error code returned.
+**
+** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
+** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
+** may set (*ppRebase) to point to a "rebase" that may be used with the
+** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
+** is set to the size of the buffer in bytes. It is the responsibility of the
+** caller to eventually free any such buffer using sqlite3_free(). The buffer
+** is only allocated and populated if one or more conflicts were encountered
+** while applying the patchset. See comments surrounding the sqlite3_rebaser
+** APIs for further details.
+**
+** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
+** may be modified by passing a combination of
+** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
+**
+** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
+** and therefore subject to change.
+*/
+SQLITE_API int sqlite3changeset_apply(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+);
+SQLITE_API int sqlite3changeset_apply_v2(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase, /* OUT: Rebase data */
+  int flags                       /* SESSION_CHANGESETAPPLY_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3changeset_apply_v2
+**
+** The following flags may passed via the 9th parameter to
+** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
+**
+** <dl>
+** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
+**   Usually, the sessions module encloses all operations performed by
+**   a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
+**   SAVEPOINT is committed if the changeset or patchset is successfully
+**   applied, or rolled back if an error occurs. Specifying this flag
+**   causes the sessions module to omit this savepoint. In this case, if the
+**   caller has an open transaction or savepoint when apply_v2() is called,
+**   it may revert the partially applied changeset by rolling it back.
+**
+** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
+**   Invert the changeset before applying it. This is equivalent to inverting
+**   a changeset using sqlite3changeset_invert() before applying it. It is
+**   an error to specify this flag with a patchset.
+**
+** <dt>SQLITE_CHANGESETAPPLY_IGNORENOOP <dd>
+**   Do not invoke the conflict handler callback for any changes that
+**   would not actually modify the database even if they were applied.
+**   Specifically, this means that the conflict handler is not invoked
+**   for:
+**    <ul>
+**    <li>a delete change if the row being deleted cannot be found,
+**    <li>an update change if the modified fields are already set to
+**        their new values in the conflicting row, or
+**    <li>an insert change if all fields of the conflicting row match
+**        the row being inserted.
+**    </ul>
+**
+** <dt>SQLITE_CHANGESETAPPLY_FKNOACTION <dd>
+**   If this flag it set, then all foreign key constraints in the target
+**   database behave as if they were declared with "ON UPDATE NO ACTION ON
+**   DELETE NO ACTION", even if they are actually CASCADE, RESTRICT, SET NULL
+**   or SET DEFAULT.
+*/
+#define SQLITE_CHANGESETAPPLY_NOSAVEPOINT   0x0001
+#define SQLITE_CHANGESETAPPLY_INVERT        0x0002
+#define SQLITE_CHANGESETAPPLY_IGNORENOOP    0x0004
+#define SQLITE_CHANGESETAPPLY_FKNOACTION    0x0008
+
+/*
+** CAPI3REF: Constants Passed To The Conflict Handler
+**
+** Values that may be passed as the second argument to a conflict-handler.
+**
+** <dl>
+** <dt>SQLITE_CHANGESET_DATA<dd>
+**   The conflict handler is invoked with CHANGESET_DATA as the second argument
+**   when processing a DELETE or UPDATE change if a row with the required
+**   PRIMARY KEY fields is present in the database, but one or more other
+**   (non primary-key) fields modified by the update do not contain the
+**   expected "before" values.
+**
+**   The conflicting row, in this case, is the database row with the matching
+**   primary key.
+**
+** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
+**   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
+**   argument when processing a DELETE or UPDATE change if a row with the
+**   required PRIMARY KEY fields is not present in the database.
+**
+**   There is no conflicting row in this case. The results of invoking the
+**   sqlite3changeset_conflict() API are undefined.
+**
+** <dt>SQLITE_CHANGESET_CONFLICT<dd>
+**   CHANGESET_CONFLICT is passed as the second argument to the conflict
+**   handler while processing an INSERT change if the operation would result
+**   in duplicate primary key values.
+**
+**   The conflicting row in this case is the database row with the matching
+**   primary key.
+**
+** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
+**   If foreign key handling is enabled, and applying a changeset leaves the
+**   database in a state containing foreign key violations, the conflict
+**   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
+**   exactly once before the changeset is committed. If the conflict handler
+**   returns CHANGESET_OMIT, the changes, including those that caused the
+**   foreign key constraint violation, are committed. Or, if it returns
+**   CHANGESET_ABORT, the changeset is rolled back.
+**
+**   No current or conflicting row information is provided. The only function
+**   it is possible to call on the supplied sqlite3_changeset_iter handle
+**   is sqlite3changeset_fk_conflicts().
+**
+** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
+**   If any other constraint violation occurs while applying a change (i.e.
+**   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
+**   invoked with CHANGESET_CONSTRAINT as the second argument.
+**
+**   There is no conflicting row in this case. The results of invoking the
+**   sqlite3changeset_conflict() API are undefined.
+**
+** </dl>
+*/
+#define SQLITE_CHANGESET_DATA        1
+#define SQLITE_CHANGESET_NOTFOUND    2
+#define SQLITE_CHANGESET_CONFLICT    3
+#define SQLITE_CHANGESET_CONSTRAINT  4
+#define SQLITE_CHANGESET_FOREIGN_KEY 5
+
+/*
+** CAPI3REF: Constants Returned By The Conflict Handler
+**
+** A conflict handler callback must return one of the following three values.
+**
+** <dl>
+** <dt>SQLITE_CHANGESET_OMIT<dd>
+**   If a conflict handler returns this value no special action is taken. The
+**   change that caused the conflict is not applied. The session module
+**   continues to the next change in the changeset.
+**
+** <dt>SQLITE_CHANGESET_REPLACE<dd>
+**   This value may only be returned if the second argument to the conflict
+**   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
+**   is not the case, any changes applied so far are rolled back and the
+**   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
+**
+**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
+**   handler, then the conflicting row is either updated or deleted, depending
+**   on the type of change.
+**
+**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
+**   handler, then the conflicting row is removed from the database and a
+**   second attempt to apply the change is made. If this second attempt fails,
+**   the original row is restored to the database before continuing.
+**
+** <dt>SQLITE_CHANGESET_ABORT<dd>
+**   If this value is returned, any changes applied so far are rolled back
+**   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
+** </dl>
+*/
+#define SQLITE_CHANGESET_OMIT       0
+#define SQLITE_CHANGESET_REPLACE    1
+#define SQLITE_CHANGESET_ABORT      2
+
+/*
+** CAPI3REF: Rebasing changesets
+** EXPERIMENTAL
+**
+** Suppose there is a site hosting a database in state S0. And that
+** modifications are made that move that database to state S1 and a
+** changeset recorded (the "local" changeset). Then, a changeset based
+** on S0 is received from another site (the "remote" changeset) and
+** applied to the database. The database is then in state
+** (S1+"remote"), where the exact state depends on any conflict
+** resolution decisions (OMIT or REPLACE) made while applying "remote".
+** Rebasing a changeset is to update it to take those conflict
+** resolution decisions into account, so that the same conflicts
+** do not have to be resolved elsewhere in the network.
+**
+** For example, if both the local and remote changesets contain an
+** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
+**
+**   local:  INSERT INTO t1 VALUES(1, 'v1');
+**   remote: INSERT INTO t1 VALUES(1, 'v2');
+**
+** and the conflict resolution is REPLACE, then the INSERT change is
+** removed from the local changeset (it was overridden). Or, if the
+** conflict resolution was "OMIT", then the local changeset is modified
+** to instead contain:
+**
+**           UPDATE t1 SET b = 'v2' WHERE a=1;
+**
+** Changes within the local changeset are rebased as follows:
+**
+** <dl>
+** <dt>Local INSERT<dd>
+**   This may only conflict with a remote INSERT. If the conflict
+**   resolution was OMIT, then add an UPDATE change to the rebased
+**   changeset. Or, if the conflict resolution was REPLACE, add
+**   nothing to the rebased changeset.
+**
+** <dt>Local DELETE<dd>
+**   This may conflict with a remote UPDATE or DELETE. In both cases the
+**   only possible resolution is OMIT. If the remote operation was a
+**   DELETE, then add no change to the rebased changeset. If the remote
+**   operation was an UPDATE, then the old.* fields of change are updated
+**   to reflect the new.* values in the UPDATE.
+**
+** <dt>Local UPDATE<dd>
+**   This may conflict with a remote UPDATE or DELETE. If it conflicts
+**   with a DELETE, and the conflict resolution was OMIT, then the update
+**   is changed into an INSERT. Any undefined values in the new.* record
+**   from the update change are filled in using the old.* values from
+**   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
+**   the UPDATE change is simply omitted from the rebased changeset.
+**
+**   If conflict is with a remote UPDATE and the resolution is OMIT, then
+**   the old.* values are rebased using the new.* values in the remote
+**   change. Or, if the resolution is REPLACE, then the change is copied
+**   into the rebased changeset with updates to columns also updated by
+**   the conflicting remote UPDATE removed. If this means no columns would
+**   be updated, the change is omitted.
+** </dl>
+**
+** A local change may be rebased against multiple remote changes
+** simultaneously. If a single key is modified by multiple remote
+** changesets, they are combined as follows before the local changeset
+** is rebased:
+**
+** <ul>
+**    <li> If there has been one or more REPLACE resolutions on a
+**         key, it is rebased according to a REPLACE.
+**
+**    <li> If there have been no REPLACE resolutions on a key, then
+**         the local changeset is rebased according to the most recent
+**         of the OMIT resolutions.
+** </ul>
+**
+** Note that conflict resolutions from multiple remote changesets are
+** combined on a per-field basis, not per-row. This means that in the
+** case of multiple remote UPDATE operations, some fields of a single
+** local change may be rebased for REPLACE while others are rebased for
+** OMIT.
+**
+** In order to rebase a local changeset, the remote changeset must first
+** be applied to the local database using sqlite3changeset_apply_v2() and
+** the buffer of rebase information captured. Then:
+**
+** <ol>
+**   <li> An sqlite3_rebaser object is created by calling
+**        sqlite3rebaser_create().
+**   <li> The new object is configured with the rebase buffer obtained from
+**        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
+**        If the local changeset is to be rebased against multiple remote
+**        changesets, then sqlite3rebaser_configure() should be called
+**        multiple times, in the same order that the multiple
+**        sqlite3changeset_apply_v2() calls were made.
+**   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
+**   <li> The sqlite3_rebaser object is deleted by calling
+**        sqlite3rebaser_delete().
+** </ol>
+*/
+typedef struct sqlite3_rebaser sqlite3_rebaser;
+
+/*
+** CAPI3REF: Create a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
+** point to the new object and return SQLITE_OK. Otherwise, if an error
+** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
+** to NULL.
+*/
+SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
+
+/*
+** CAPI3REF: Configure a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Configure the changeset rebaser object to rebase changesets according
+** to the conflict resolutions described by buffer pRebase (size nRebase
+** bytes), which must have been obtained from a previous call to
+** sqlite3changeset_apply_v2().
+*/
+SQLITE_API int sqlite3rebaser_configure(
+  sqlite3_rebaser*,
+  int nRebase, const void *pRebase
+);
+
+/*
+** CAPI3REF: Rebase a changeset
+** EXPERIMENTAL
+**
+** Argument pIn must point to a buffer containing a changeset nIn bytes
+** in size. This function allocates and populates a buffer with a copy
+** of the changeset rebased according to the configuration of the
+** rebaser object passed as the first argument. If successful, (*ppOut)
+** is set to point to the new buffer containing the rebased changeset and
+** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
+** responsibility of the caller to eventually free the new buffer using
+** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
+** are set to zero and an SQLite error code returned.
+*/
+SQLITE_API int sqlite3rebaser_rebase(
+  sqlite3_rebaser*,
+  int nIn, const void *pIn,
+  int *pnOut, void **ppOut
+);
+
+/*
+** CAPI3REF: Delete a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Delete the changeset rebaser object and all associated resources. There
+** should be one call to this function for each successful invocation
+** of sqlite3rebaser_create().
+*/
+SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
+
+/*
+** CAPI3REF: Streaming Versions of API functions.
+**
+** The six streaming API xxx_strm() functions serve similar purposes to the
+** corresponding non-streaming API functions:
+**
+** <table border=1 style="margin-left:8ex;margin-right:8ex">
+**   <tr><th>Streaming function<th>Non-streaming equivalent</th>
+**   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
+**   <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
+**   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
+**   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
+**   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
+**   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
+**   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
+** </table>
+**
+** Non-streaming functions that accept changesets (or patchsets) as input
+** require that the entire changeset be stored in a single buffer in memory.
+** Similarly, those that return a changeset or patchset do so by returning
+** a pointer to a single large buffer allocated using sqlite3_malloc().
+** Normally this is convenient. However, if an application running in a
+** low-memory environment is required to handle very large changesets, the
+** large contiguous memory allocations required can become onerous.
+**
+** In order to avoid this problem, instead of a single large buffer, input
+** is passed to a streaming API functions by way of a callback function that
+** the sessions module invokes to incrementally request input data as it is
+** required. In all cases, a pair of API function parameters such as
+**
+**  <pre>
+**        int nChangeset,
+**        void *pChangeset,
+**  </pre>
+**
+** Is replaced by:
+**
+**  <pre>
+**        int (*xInput)(void *pIn, void *pData, int *pnData),
+**        void *pIn,
+**  </pre>
+**
+** Each time the xInput callback is invoked by the sessions module, the first
+** argument passed is a copy of the supplied pIn context pointer. The second
+** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
+** error occurs the xInput method should copy up to (*pnData) bytes of data
+** into the buffer and set (*pnData) to the actual number of bytes copied
+** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
+** should be set to zero to indicate this. Or, if an error occurs, an SQLite
+** error code should be returned. In all cases, if an xInput callback returns
+** an error, all processing is abandoned and the streaming API function
+** returns a copy of the error code to the caller.
+**
+** In the case of sqlite3changeset_start_strm(), the xInput callback may be
+** invoked by the sessions module at any point during the lifetime of the
+** iterator. If such an xInput callback returns an error, the iterator enters
+** an error state, whereby all subsequent calls to iterator functions
+** immediately fail with the same error code as returned by xInput.
+**
+** Similarly, streaming API functions that return changesets (or patchsets)
+** return them in chunks by way of a callback function instead of via a
+** pointer to a single large buffer. In this case, a pair of parameters such
+** as:
+**
+**  <pre>
+**        int *pnChangeset,
+**        void **ppChangeset,
+**  </pre>
+**
+** Is replaced by:
+**
+**  <pre>
+**        int (*xOutput)(void *pOut, const void *pData, int nData),
+**        void *pOut
+**  </pre>
+**
+** The xOutput callback is invoked zero or more times to return data to
+** the application. The first parameter passed to each call is a copy of the
+** pOut pointer supplied by the application. The second parameter, pData,
+** points to a buffer nData bytes in size containing the chunk of output
+** data being returned. If the xOutput callback successfully processes the
+** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
+** it should return some other SQLite error code. In this case processing
+** is immediately abandoned and the streaming API function returns a copy
+** of the xOutput error code to the application.
+**
+** The sessions module never invokes an xOutput callback with the third
+** parameter set to a value less than or equal to zero. Other than this,
+** no guarantees are made as to the size of the chunks of data returned.
+*/
+SQLITE_API int sqlite3changeset_apply_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+);
+SQLITE_API int sqlite3changeset_apply_v2_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase,
+  int flags
+);
+SQLITE_API int sqlite3changeset_concat_strm(
+  int (*xInputA)(void *pIn, void *pData, int *pnData),
+  void *pInA,
+  int (*xInputB)(void *pIn, void *pData, int *pnData),
+  void *pInB,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changeset_invert_strm(
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changeset_start_strm(
+  sqlite3_changeset_iter **pp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn
+);
+SQLITE_API int sqlite3changeset_start_v2_strm(
+  sqlite3_changeset_iter **pp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int flags
+);
+SQLITE_API int sqlite3session_changeset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3session_patchset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
+    int (*xInput)(void *pIn, void *pData, int *pnData),
+    void *pIn
+);
+SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
+    int (*xOutput)(void *pOut, const void *pData, int nData),
+    void *pOut
+);
+SQLITE_API int sqlite3rebaser_rebase_strm(
+  sqlite3_rebaser *pRebaser,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+
+/*
+** CAPI3REF: Configure global parameters
+**
+** The sqlite3session_config() interface is used to make global configuration
+** changes to the sessions module in order to tune it to the specific needs
+** of the application.
+**
+** The sqlite3session_config() interface is not threadsafe. If it is invoked
+** while any other thread is inside any other sessions method then the
+** results are undefined. Furthermore, if it is invoked after any sessions
+** related objects have been created, the results are also undefined.
+**
+** The first argument to the sqlite3session_config() function must be one
+** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
+** interpretation of the (void*) value passed as the second parameter and
+** the effect of calling this function depends on the value of the first
+** parameter.
+**
+** <dl>
+** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
+**    By default, the sessions module streaming interfaces attempt to input
+**    and output data in approximately 1 KiB chunks. This operand may be used
+**    to set and query the value of this configuration setting. The pointer
+**    passed as the second argument must point to a value of type (int).
+**    If this value is greater than 0, it is used as the new streaming data
+**    chunk size for both input and output. Before returning, the (int) value
+**    pointed to by pArg is set to the final value of the streaming interface
+**    chunk size.
+** </dl>
+**
+** This function returns SQLITE_OK if successful, or an SQLite error code
+** otherwise.
+*/
+SQLITE_API int sqlite3session_config(int op, void *pArg);
+
+/*
+** CAPI3REF: Values for sqlite3session_config().
+*/
+#define SQLITE_SESSION_CONFIG_STRMSIZE 1
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#if 0
+}
+#endif
+
+#endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
+
+/******** End of sqlite3session.h *********/
+/******** Begin file fts5.h *********/
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Interfaces to extend FTS5. Using the interfaces defined in this file,
+** FTS5 may be extended with:
+**
+**     * custom tokenizers, and
+**     * custom auxiliary functions.
+*/
+
+
+#ifndef _FTS5_H
+#define _FTS5_H
+
+
+#if 0
+extern "C" {
+#endif
+
+/*************************************************************************
+** CUSTOM AUXILIARY FUNCTIONS
+**
+** Virtual table implementations may overload SQL functions by implementing
+** the sqlite3_module.xFindFunction() method.
+*/
+
+typedef struct Fts5ExtensionApi Fts5ExtensionApi;
+typedef struct Fts5Context Fts5Context;
+typedef struct Fts5PhraseIter Fts5PhraseIter;
+
+typedef void (*fts5_extension_function)(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+);
+
+struct Fts5PhraseIter {
+  const unsigned char *a;
+  const unsigned char *b;
+};
+
+/*
+** EXTENSION API FUNCTIONS
+**
+** xUserData(pFts):
+**   Return a copy of the pUserData pointer passed to the xCreateFunction()
+**   API when the extension function was registered.
+**
+** xColumnTotalSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the FTS5 table. Or, if iCol is
+**   non-negative but less than the number of columns in the table, return
+**   the total number of tokens in column iCol, considering all rows in
+**   the FTS5 table.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+** xColumnCount(pFts):
+**   Return the number of columns in the table.
+**
+** xColumnSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the current row. Or, if iCol is
+**   non-negative but less than the number of columns in the table, set
+**   *pnToken to the number of tokens in column iCol of the current row.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+**   This function may be quite inefficient if used with an FTS5 table
+**   created with the "columnsize=0" option.
+**
+** xColumnText:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the text of column iCol of
+**   the current document. If successful, (*pz) is set to point to a buffer
+**   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
+**   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
+**   if an error occurs, an SQLite error code is returned and the final values
+**   of (*pz) and (*pn) are undefined.
+**
+** xPhraseCount:
+**   Returns the number of phrases in the current query expression.
+**
+** xPhraseSize:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of phrases in the current query, as returned by xPhraseCount,
+**   0 is returned. Otherwise, this function returns the number of tokens in
+**   phrase iPhrase of the query. Phrases are numbered starting from zero.
+**
+** xInstCount:
+**   Set *pnInst to the total number of occurrences of all phrases within
+**   the query within the current row. Return SQLITE_OK if successful, or
+**   an error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always returns 0.
+**
+** xInst:
+**   Query for the details of phrase match iIdx within the current row.
+**   Phrase matches are numbered starting from zero, so the iIdx argument
+**   should be greater than or equal to zero and smaller than the value
+**   output by xInstCount(). If iIdx is less than zero or greater than
+**   or equal to the value returned by xInstCount(), SQLITE_RANGE is returned.
+**
+**   Otherwise, output parameter *piPhrase is set to the phrase number, *piCol
+**   to the column in which it occurs and *piOff the token offset of the
+**   first token of the phrase. SQLITE_OK is returned if successful, or an
+**   error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xRowid:
+**   Returns the rowid of the current row.
+**
+** xTokenize:
+**   Tokenize text using the tokenizer belonging to the FTS5 table.
+**
+** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
+**   This API function is used to query the FTS table for phrase iPhrase
+**   of the current query. Specifically, a query equivalent to:
+**
+**       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
+**
+**   with $p set to a phrase equivalent to the phrase iPhrase of the
+**   current query is executed. Any column filter that applies to
+**   phrase iPhrase of the current query is included in $p. For each
+**   row visited, the callback function passed as the fourth argument
+**   is invoked. The context and API objects passed to the callback
+**   function may be used to access the properties of each matched row.
+**   Invoking Api.xUserData() returns a copy of the pointer passed as
+**   the third argument to pUserData.
+**
+**   If parameter iPhrase is less than zero, or greater than or equal to
+**   the number of phrases in the query, as returned by xPhraseCount(),
+**   this function returns SQLITE_RANGE.
+**
+**   If the callback function returns any value other than SQLITE_OK, the
+**   query is abandoned and the xQueryPhrase function returns immediately.
+**   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
+**   Otherwise, the error code is propagated upwards.
+**
+**   If the query runs to completion without incident, SQLITE_OK is returned.
+**   Or, if some error occurs before the query completes or is aborted by
+**   the callback, an SQLite error code is returned.
+**
+**
+** xSetAuxdata(pFts5, pAux, xDelete)
+**
+**   Save the pointer passed as the second argument as the extension function's
+**   "auxiliary data". The pointer may then be retrieved by the current or any
+**   future invocation of the same fts5 extension function made as part of
+**   the same MATCH query using the xGetAuxdata() API.
+**
+**   Each extension function is allocated a single auxiliary data slot for
+**   each FTS query (MATCH expression). If the extension function is invoked
+**   more than once for a single FTS query, then all invocations share a
+**   single auxiliary data context.
+**
+**   If there is already an auxiliary data pointer when this function is
+**   invoked, then it is replaced by the new pointer. If an xDelete callback
+**   was specified along with the original pointer, it is invoked at this
+**   point.
+**
+**   The xDelete callback, if one is specified, is also invoked on the
+**   auxiliary data pointer after the FTS5 query has finished.
+**
+**   If an error (e.g. an OOM condition) occurs within this function,
+**   the auxiliary data is set to NULL and an error code returned. If the
+**   xDelete parameter was not NULL, it is invoked on the auxiliary data
+**   pointer before returning.
+**
+**
+** xGetAuxdata(pFts5, bClear)
+**
+**   Returns the current auxiliary data pointer for the fts5 extension
+**   function. See the xSetAuxdata() method for details.
+**
+**   If the bClear argument is non-zero, then the auxiliary data is cleared
+**   (set to NULL) before this function returns. In this case the xDelete,
+**   if any, is not invoked.
+**
+**
+** xRowCount(pFts5, pnRow)
+**
+**   This function is used to retrieve the total number of rows in the table.
+**   In other words, the same value that would be returned by:
+**
+**        SELECT count(*) FROM ftstable;
+**
+** xPhraseFirst()
+**   This function is used, along with type Fts5PhraseIter and the xPhraseNext
+**   method, to iterate through all instances of a single query phrase within
+**   the current row. This is the same information as is accessible via the
+**   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
+**   to use, this API may be faster under some circumstances. To iterate
+**   through instances of phrase iPhrase, use the following code:
+**
+**       Fts5PhraseIter iter;
+**       int iCol, iOff;
+**       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
+**           iCol>=0;
+**           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
+**       ){
+**         // An instance of phrase iPhrase at offset iOff of column iCol
+**       }
+**
+**   The Fts5PhraseIter structure is defined above. Applications should not
+**   modify this structure directly - it should only be used as shown above
+**   with the xPhraseFirst() and xPhraseNext() API methods (and by
+**   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always iterates
+**   through an empty set (all calls to xPhraseFirst() set iCol to -1).
+**
+**   In all cases, matches are visited in (column ASC, offset ASC) order.
+**   i.e. all those in column 0, sorted by offset, followed by those in
+**   column 1, etc.
+**
+** xPhraseNext()
+**   See xPhraseFirst above.
+**
+** xPhraseFirstColumn()
+**   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
+**   and xPhraseNext() APIs described above. The difference is that instead
+**   of iterating through all instances of a phrase in the current row, these
+**   APIs are used to iterate through the set of columns in the current row
+**   that contain one or more instances of a specified phrase. For example:
+**
+**       Fts5PhraseIter iter;
+**       int iCol;
+**       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
+**           iCol>=0;
+**           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
+**       ){
+**         // Column iCol contains at least one instance of phrase iPhrase
+**       }
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" option. If the FTS5 table is created with either
+**   "detail=none" "content=" option (i.e. if it is a contentless table),
+**   then this API always iterates through an empty set (all calls to
+**   xPhraseFirstColumn() set iCol to -1).
+**
+**   The information accessed using this API and its companion
+**   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
+**   (or xInst/xInstCount). The chief advantage of this API is that it is
+**   significantly more efficient than those alternatives when used with
+**   "detail=column" tables.
+**
+** xPhraseNextColumn()
+**   See xPhraseFirstColumn above.
+**
+** xQueryToken(pFts5, iPhrase, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase iPhrase of the current
+**   query. Before returning, output parameter *ppToken is set to point
+**   to a buffer containing the requested token, and *pnToken to the
+**   size of this buffer in bytes.
+**
+**   If iPhrase or iToken are less than zero, or if iPhrase is greater than
+**   or equal to the number of phrases in the query as reported by
+**   xPhraseCount(), or if iToken is equal to or greater than the number of
+**   tokens in the phrase, SQLITE_RANGE is returned and *ppToken and *pnToken
+     are both zeroed.
+**
+**   The output text is not a copy of the query text that specified the
+**   token. It is the output of the tokenizer module. For tokendata=1
+**   tables, this includes any embedded 0x00 and trailing data.
+**
+** xInstToken(pFts5, iIdx, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase hit iIdx within the
+**   current row. If iIdx is less than zero or greater than or equal to the
+**   value returned by xInstCount(), SQLITE_RANGE is returned.  Otherwise,
+**   output variable (*ppToken) is set to point to a buffer containing the
+**   matching document token, and (*pnToken) to the size of that buffer in
+**   bytes.
+**
+**   The output text is not a copy of the document text that was tokenized.
+**   It is the output of the tokenizer module. For tokendata=1 tables, this
+**   includes any embedded 0x00 and trailing data.
+**
+**   This API may be slow in some cases if the token identified by parameters
+**   iIdx and iToken matched a prefix token in the query. In most cases, the
+**   first call to this API for each prefix token in the query is forced
+**   to scan the portion of the full-text index that matches the prefix
+**   token to collect the extra data required by this API. If the prefix
+**   token matches a large number of token instances in the document set,
+**   this may be a performance problem.
+**
+**   If the user knows in advance that a query may use this API for a
+**   prefix token, FTS5 may be configured to collect all required data as part
+**   of the initial querying of the full-text index, avoiding the second scan
+**   entirely. This also causes prefix queries that do not use this API to
+**   run more slowly and use more memory. FTS5 may be configured in this way
+**   either on a per-table basis using the [FTS5 insttoken | 'insttoken']
+**   option, or on a per-query basis using the
+**   [fts5_insttoken | fts5_insttoken()] user function.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xColumnLocale(pFts5, iIdx, pzLocale, pnLocale)
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the locale associated
+**   with column iCol of the current row. Usually, there is no associated
+**   locale, and output parameters (*pzLocale) and (*pnLocale) are set
+**   to NULL and 0, respectively. However, if the fts5_locale() function
+**   was used to associate a locale with the value when it was inserted
+**   into the fts5 table, then (*pzLocale) is set to point to a nul-terminated
+**   buffer containing the name of the locale in utf-8 encoding. (*pnLocale)
+**   is set to the size in bytes of the buffer, not including the
+**   nul-terminator.
+**
+**   If successful, SQLITE_OK is returned. Or, if an error occurs, an
+**   SQLite error code is returned. The final value of the output parameters
+**   is undefined in this case.
+**
+** xTokenize_v2:
+**   Tokenize text using the tokenizer belonging to the FTS5 table. This
+**   API is the same as the xTokenize() API, except that it allows a tokenizer
+**   locale to be specified.
+*/
+struct Fts5ExtensionApi {
+  int iVersion;                   /* Currently always set to 4 */
+
+  void *(*xUserData)(Fts5Context*);
+
+  int (*xColumnCount)(Fts5Context*);
+  int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
+  int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
+
+  int (*xTokenize)(Fts5Context*,
+    const char *pText, int nText, /* Text to tokenize */
+    void *pCtx,                   /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+
+  int (*xPhraseCount)(Fts5Context*);
+  int (*xPhraseSize)(Fts5Context*, int iPhrase);
+
+  int (*xInstCount)(Fts5Context*, int *pnInst);
+  int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
+
+  sqlite3_int64 (*xRowid)(Fts5Context*);
+  int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
+
+  int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
+    int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
+  );
+  int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
+  void *(*xGetAuxdata)(Fts5Context*, int bClear);
+
+  int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
+  void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
+
+  int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
+  void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
+
+  /* Below this point are iVersion>=3 only */
+  int (*xQueryToken)(Fts5Context*,
+      int iPhrase, int iToken,
+      const char **ppToken, int *pnToken
+  );
+  int (*xInstToken)(Fts5Context*, int iIdx, int iToken, const char**, int*);
+
+  /* Below this point are iVersion>=4 only */
+  int (*xColumnLocale)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xTokenize_v2)(Fts5Context*,
+    const char *pText, int nText,      /* Text to tokenize */
+    const char *pLocale, int nLocale,  /* Locale to pass to tokenizer */
+    void *pCtx,                        /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+};
+
+/*
+** CUSTOM AUXILIARY FUNCTIONS
+*************************************************************************/
+
+/*************************************************************************
+** CUSTOM TOKENIZERS
+**
+** Applications may also register custom tokenizer types. A tokenizer
+** is registered by providing fts5 with a populated instance of the
+** following structure. All structure methods must be defined, setting
+** any member of the fts5_tokenizer struct to NULL leads to undefined
+** behaviour. The structure methods are expected to function as follows:
+**
+** xCreate:
+**   This function is used to allocate and initialize a tokenizer instance.
+**   A tokenizer instance is required to actually tokenize text.
+**
+**   The first argument passed to this function is a copy of the (void*)
+**   pointer provided by the application when the fts5_tokenizer_v2 object
+**   was registered with FTS5 (the third argument to xCreateTokenizer()).
+**   The second and third arguments are an array of nul-terminated strings
+**   containing the tokenizer arguments, if any, specified following the
+**   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
+**   to create the FTS5 table.
+**
+**   The final argument is an output variable. If successful, (*ppOut)
+**   should be set to point to the new tokenizer handle and SQLITE_OK
+**   returned. If an error occurs, some value other than SQLITE_OK should
+**   be returned. In this case, fts5 assumes that the final value of *ppOut
+**   is undefined.
+**
+** xDelete:
+**   This function is invoked to delete a tokenizer handle previously
+**   allocated using xCreate(). Fts5 guarantees that this function will
+**   be invoked exactly once for each successful call to xCreate().
+**
+** xTokenize:
+**   This function is expected to tokenize the nText byte string indicated
+**   by argument pText. pText may or may not be nul-terminated. The first
+**   argument passed to this function is a pointer to an Fts5Tokenizer object
+**   returned by an earlier call to xCreate().
+**
+**   The third argument indicates the reason that FTS5 is requesting
+**   tokenization of the supplied text. This is always one of the following
+**   four values:
+**
+**   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
+**            or removed from the FTS table. The tokenizer is being invoked to
+**            determine the set of tokens to add to (or delete from) the
+**            FTS index.
+**
+**       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
+**            against the FTS index. The tokenizer is being called to tokenize
+**            a bareword or quoted string specified as part of the query.
+**
+**       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
+**            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
+**            followed by a "*" character, indicating that the last token
+**            returned by the tokenizer will be treated as a token prefix.
+**
+**       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
+**            satisfy an fts5_api.xTokenize() request made by an auxiliary
+**            function. Or an fts5_api.xColumnSize() request made by the same
+**            on a columnsize=0 database.
+**   </ul>
+**
+**   The sixth and seventh arguments passed to xTokenize() - pLocale and
+**   nLocale - are a pointer to a buffer containing the locale to use for
+**   tokenization (e.g. "en_US") and its size in bytes, respectively. The
+**   pLocale buffer is not nul-terminated. pLocale may be passed NULL (in
+**   which case nLocale is always 0) to indicate that the tokenizer should
+**   use its default locale.
+**
+**   For each token in the input string, the supplied callback xToken() must
+**   be invoked. The first argument to it should be a copy of the pointer
+**   passed as the second argument to xTokenize(). The third and fourth
+**   arguments are a pointer to a buffer containing the token text, and the
+**   size of the token in bytes. The 4th and 5th arguments are the byte offsets
+**   of the first byte of and first byte immediately following the text from
+**   which the token is derived within the input.
+**
+**   The second argument passed to the xToken() callback ("tflags") should
+**   normally be set to 0. The exception is if the tokenizer supports
+**   synonyms. In this case see the discussion below for details.
+**
+**   FTS5 assumes the xToken() callback is invoked for each token in the
+**   order that they occur within the input text.
+**
+**   If an xToken() callback returns any value other than SQLITE_OK, then
+**   the tokenization should be abandoned and the xTokenize() method should
+**   immediately return a copy of the xToken() return value. Or, if the
+**   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
+**   if an error occurs with the xTokenize() implementation itself, it
+**   may abandon the tokenization and return any error code other than
+**   SQLITE_OK or SQLITE_DONE.
+**
+**   If the tokenizer is registered using an fts5_tokenizer_v2 object,
+**   then the xTokenize() method has two additional arguments - pLocale
+**   and nLocale. These specify the locale that the tokenizer should use
+**   for the current request. If pLocale and nLocale are both 0, then the
+**   tokenizer should use its default locale. Otherwise, pLocale points to
+**   an nLocale byte buffer containing the name of the locale to use as utf-8
+**   text. pLocale is not nul-terminated.
+**
+** FTS5_TOKENIZER
+**
+** There is also an fts5_tokenizer object. This is an older, deprecated,
+** version of fts5_tokenizer_v2. It is similar except that:
+**
+**  <ul>
+**    <li> There is no "iVersion" field, and
+**    <li> The xTokenize() method does not take a locale argument.
+**  </ul>
+**
+** Legacy fts5_tokenizer tokenizers must be registered using the
+** legacy xCreateTokenizer() function, instead of xCreateTokenizer_v2().
+**
+** Tokenizer implementations registered using either API may be retrieved
+** using both xFindTokenizer() and xFindTokenizer_v2().
+**
+** SYNONYM SUPPORT
+**
+**   Custom tokenizers may also support synonyms. Consider a case in which a
+**   user wishes to query for a phrase such as "first place". Using the
+**   built-in tokenizers, the FTS5 query 'first + place' will match instances
+**   of "first place" within the document set, but not alternative forms
+**   such as "1st place". In some applications, it would be better to match
+**   all instances of "first place" or "1st place" regardless of which form
+**   the user specified in the MATCH query text.
+**
+**   There are several ways to approach this in FTS5:
+**
+**   <ol><li> By mapping all synonyms to a single token. In this case, using
+**            the above example, this means that the tokenizer returns the
+**            same token for inputs "first" and "1st". Say that token is in
+**            fact "first", so that when the user inserts the document "I won
+**            1st place" entries are added to the index for tokens "i", "won",
+**            "first" and "place". If the user then queries for '1st + place',
+**            the tokenizer substitutes "first" for "1st" and the query works
+**            as expected.
+**
+**       <li> By querying the index for all synonyms of each query term
+**            separately. In this case, when tokenizing query text, the
+**            tokenizer may provide multiple synonyms for a single term
+**            within the document. FTS5 then queries the index for each
+**            synonym individually. For example, faced with the query:
+**
+**   <codeblock>
+**     ... MATCH 'first place'</codeblock>
+**
+**            the tokenizer offers both "1st" and "first" as synonyms for the
+**            first token in the MATCH query and FTS5 effectively runs a query
+**            similar to:
+**
+**   <codeblock>
+**     ... MATCH '(first OR 1st) place'</codeblock>
+**
+**            except that, for the purposes of auxiliary functions, the query
+**            still appears to contain just two phrases - "(first OR 1st)"
+**            being treated as a single phrase.
+**
+**       <li> By adding multiple synonyms for a single term to the FTS index.
+**            Using this method, when tokenizing document text, the tokenizer
+**            provides multiple synonyms for each token. So that when a
+**            document such as "I won first place" is tokenized, entries are
+**            added to the FTS index for "i", "won", "first", "1st" and
+**            "place".
+**
+**            This way, even if the tokenizer does not provide synonyms
+**            when tokenizing query text (it should not - to do so would be
+**            inefficient), it doesn't matter if the user queries for
+**            'first + place' or '1st + place', as there are entries in the
+**            FTS index corresponding to both forms of the first token.
+**   </ol>
+**
+**   Whether it is parsing document or query text, any call to xToken that
+**   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
+**   is considered to supply a synonym for the previous token. For example,
+**   when parsing the document "I won first place", a tokenizer that supports
+**   synonyms would call xToken() 5 times, as follows:
+**
+**   <codeblock>
+**       xToken(pCtx, 0, "i",                      1,  0,  1);
+**       xToken(pCtx, 0, "won",                    3,  2,  5);
+**       xToken(pCtx, 0, "first",                  5,  6, 11);
+**       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
+**       xToken(pCtx, 0, "place",                  5, 12, 17);
+**</codeblock>
+**
+**   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
+**   xToken() is called. Multiple synonyms may be specified for a single token
+**   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
+**   There is no limit to the number of synonyms that may be provided for a
+**   single token.
+**
+**   In many cases, method (1) above is the best approach. It does not add
+**   extra data to the FTS index or require FTS5 to query for multiple terms,
+**   so it is efficient in terms of disk space and query speed. However, it
+**   does not support prefix queries very well. If, as suggested above, the
+**   token "first" is substituted for "1st" by the tokenizer, then the query:
+**
+**   <codeblock>
+**     ... MATCH '1s*'</codeblock>
+**
+**   will not match documents that contain the token "1st" (as the tokenizer
+**   will probably not map "1s" to any prefix of "first").
+**
+**   For full prefix support, method (3) may be preferred. In this case,
+**   because the index contains entries for both "first" and "1st", prefix
+**   queries such as 'fi*' or '1s*' will match correctly. However, because
+**   extra entries are added to the FTS index, this method uses more space
+**   within the database.
+**
+**   Method (2) offers a midpoint between (1) and (3). Using this method,
+**   a query such as '1s*' will match documents that contain the literal
+**   token "1st", but not "first" (assuming the tokenizer is not able to
+**   provide synonyms for prefixes). However, a non-prefix query like '1st'
+**   will match against "1st" and "first". This method does not require
+**   extra disk space, as no extra entries are added to the FTS index.
+**   On the other hand, it may require more CPU cycles to run MATCH queries,
+**   as separate queries of the FTS index are required for each synonym.
+**
+**   When using methods (2) or (3), it is important that the tokenizer only
+**   provide synonyms when tokenizing document text (method (3)) or query
+**   text (method (2)), not both. Doing so will not cause any errors, but is
+**   inefficient.
+*/
+typedef struct Fts5Tokenizer Fts5Tokenizer;
+typedef struct fts5_tokenizer_v2 fts5_tokenizer_v2;
+struct fts5_tokenizer_v2 {
+  int iVersion;             /* Currently always 2 */
+
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      const char *pLocale, int nLocale,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+/*
+** New code should use the fts5_tokenizer_v2 type to define tokenizer
+** implementations. The following type is included for legacy applications
+** that still use it.
+*/
+typedef struct fts5_tokenizer fts5_tokenizer;
+struct fts5_tokenizer {
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+
+/* Flags that may be passed as the third argument to xTokenize() */
+#define FTS5_TOKENIZE_QUERY     0x0001
+#define FTS5_TOKENIZE_PREFIX    0x0002
+#define FTS5_TOKENIZE_DOCUMENT  0x0004
+#define FTS5_TOKENIZE_AUX       0x0008
+
+/* Flags that may be passed by the tokenizer implementation back to FTS5
+** as the third argument to the supplied xToken callback. */
+#define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
+
+/*
+** END OF CUSTOM TOKENIZERS
+*************************************************************************/
+
+/*************************************************************************
+** FTS5 EXTENSION REGISTRATION API
+*/
+typedef struct fts5_api fts5_api;
+struct fts5_api {
+  int iVersion;                   /* Currently always set to 3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer *pTokenizer
+  );
+
+  /* Create a new auxiliary function */
+  int (*xCreateFunction)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_extension_function xFunction,
+    void (*xDestroy)(void*)
+  );
+
+  /* APIs below this point are only available if iVersion>=3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer_v2 *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer_v2 **ppTokenizer
+  );
+};
+
+/*
+** END OF REGISTRATION API
+*************************************************************************/
+
+#if 0
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* _FTS5_H */
+
+/******** End of fts5.h *********/
+#endif /* SQLITE3_H */
+
+/************** End of sqlite3.h *********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/*
+** Reuse the STATIC_LRU for mutex access to sqlite3_temp_directory.
+*/
+#define SQLITE_MUTEX_STATIC_TEMPDIR SQLITE_MUTEX_STATIC_VFS1
+
+/*
+** Include the configuration header output by 'configure' if we're using the
+** autoconf-based build
+*/
+#if defined(_HAVE_SQLITE_CONFIG_H) && !defined(SQLITECONFIG_H)
+#include "sqlite_cfg.h"
+#define SQLITECONFIG_H 1
+#endif
+
+/************** Include sqliteLimit.h in the middle of sqliteInt.h ***********/
+/************** Begin file sqliteLimit.h *************************************/
+/*
+** 2007 May 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file defines various limits of what SQLite can process.
+*/
+
+/*
+** The maximum length of a TEXT or BLOB in bytes.   This also
+** limits the size of a row in a table or index.
+**
+** The hard limit is the ability of a 32-bit signed integer
+** to count the size: 2^31-1 or 2147483647.
+*/
+#ifndef SQLITE_MAX_LENGTH
+# define SQLITE_MAX_LENGTH 1000000000
+#endif
+#define SQLITE_MIN_LENGTH 30   /* Minimum value for the length limit */
+
+/*
+** This is the maximum number of
+**
+**    * Columns in a table
+**    * Columns in an index
+**    * Columns in a view
+**    * Terms in the SET clause of an UPDATE statement
+**    * Terms in the result set of a SELECT statement
+**    * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement.
+**    * Terms in the VALUES clause of an INSERT statement
+**
+** The hard upper limit here is 32676.  Most database people will
+** tell you that in a well-normalized database, you usually should
+** not have more than a dozen or so columns in any table.  And if
+** that is the case, there is no point in having more than a few
+** dozen values in any of the other situations described above.
+*/
+#ifndef SQLITE_MAX_COLUMN
+# define SQLITE_MAX_COLUMN 2000
+#endif
+
+/*
+** The maximum length of a single SQL statement in bytes.
+**
+** It used to be the case that setting this value to zero would
+** turn the limit off.  That is no longer true.  It is not possible
+** to turn this limit off.
+*/
+#ifndef SQLITE_MAX_SQL_LENGTH
+# define SQLITE_MAX_SQL_LENGTH 1000000000
+#endif
+
+/*
+** The maximum depth of an expression tree. This is limited to
+** some extent by SQLITE_MAX_SQL_LENGTH. But sometime you might
+** want to place more severe limits on the complexity of an
+** expression. A value of 0 means that there is no limit.
+*/
+#ifndef SQLITE_MAX_EXPR_DEPTH
+# define SQLITE_MAX_EXPR_DEPTH 1000
+#endif
+
+/*
+** The maximum number of terms in a compound SELECT statement.
+** The code generator for compound SELECT statements does one
+** level of recursion for each term.  A stack overflow can result
+** if the number of terms is too large.  In practice, most SQL
+** never has more than 3 or 4 terms.  Use a value of 0 to disable
+** any limit on the number of terms in a compound SELECT.
+*/
+#ifndef SQLITE_MAX_COMPOUND_SELECT
+# define SQLITE_MAX_COMPOUND_SELECT 500
+#endif
+
+/*
+** The maximum number of opcodes in a VDBE program.
+** Not currently enforced.
+*/
+#ifndef SQLITE_MAX_VDBE_OP
+# define SQLITE_MAX_VDBE_OP 250000000
+#endif
+
+/*
+** The maximum number of arguments to an SQL function.
+**
+** This value has a hard upper limit of 32767 due to storage
+** constraints (it needs to fit inside a i16).  We keep it
+** lower than that to prevent abuse.
+*/
+#ifndef SQLITE_MAX_FUNCTION_ARG
+# define SQLITE_MAX_FUNCTION_ARG 1000
+#endif
+
+/*
+** The suggested maximum number of in-memory pages to use for
+** the main database table and for temporary tables.
+**
+** IMPLEMENTATION-OF: R-30185-15359 The default suggested cache size is -2000,
+** which means the cache size is limited to 2048000 bytes of memory.
+** IMPLEMENTATION-OF: R-48205-43578 The default suggested cache size can be
+** altered using the SQLITE_DEFAULT_CACHE_SIZE compile-time options.
+*/
+#ifndef SQLITE_DEFAULT_CACHE_SIZE
+# define SQLITE_DEFAULT_CACHE_SIZE  -2000
+#endif
+
+/*
+** The default number of frames to accumulate in the log file before
+** checkpointing the database in WAL mode.
+*/
+#ifndef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT
+# define SQLITE_DEFAULT_WAL_AUTOCHECKPOINT  1000
+#endif
+
+/*
+** The maximum number of attached databases.  This must be between 0
+** and 125.  The upper bound of 125 is because the attached databases are
+** counted using a signed 8-bit integer which has a maximum value of 127
+** and we have to allow 2 extra counts for the "main" and "temp" databases.
+*/
+#ifndef SQLITE_MAX_ATTACHED
+# define SQLITE_MAX_ATTACHED 10
+#endif
+
+
+/*
+** The maximum value of a ?nnn wildcard that the parser will accept.
+** If the value exceeds 32767 then extra space is required for the Expr
+** structure.  But otherwise, we believe that the number can be as large
+** as a signed 32-bit integer can hold.
+*/
+#ifndef SQLITE_MAX_VARIABLE_NUMBER
+# define SQLITE_MAX_VARIABLE_NUMBER 32766
+#endif
+
+/* Maximum page size.  The upper bound on this value is 65536.  This a limit
+** imposed by the use of 16-bit offsets within each page.
+**
+** Earlier versions of SQLite allowed the user to change this value at
+** compile time. This is no longer permitted, on the grounds that it creates
+** a library that is technically incompatible with an SQLite library
+** compiled with a different limit. If a process operating on a database
+** with a page-size of 65536 bytes crashes, then an instance of SQLite
+** compiled with the default page-size limit will not be able to rollback
+** the aborted transaction. This could lead to database corruption.
+*/
+#ifdef SQLITE_MAX_PAGE_SIZE
+# undef SQLITE_MAX_PAGE_SIZE
+#endif
+#define SQLITE_MAX_PAGE_SIZE 65536
+
+
+/*
+** The default size of a database page.
+*/
+#ifndef SQLITE_DEFAULT_PAGE_SIZE
+# define SQLITE_DEFAULT_PAGE_SIZE 4096
+#endif
+#if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
+# undef SQLITE_DEFAULT_PAGE_SIZE
+# define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
+#endif
+
+/*
+** Ordinarily, if no value is explicitly provided, SQLite creates databases
+** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain
+** device characteristics (sector-size and atomic write() support),
+** SQLite may choose a larger value. This constant is the maximum value
+** SQLite will choose on its own.
+*/
+#ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE
+# define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192
+#endif
+#if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
+# undef SQLITE_MAX_DEFAULT_PAGE_SIZE
+# define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
+#endif
+
+
+/*
+** Maximum number of pages in one database file.
+**
+** This is really just the default value for the max_page_count pragma.
+** This value can be lowered (or raised) at run-time using that the
+** max_page_count macro.
+*/
+#ifndef SQLITE_MAX_PAGE_COUNT
+# define SQLITE_MAX_PAGE_COUNT 0xfffffffe /* 4294967294 */
+#endif
+
+/*
+** Maximum length (in bytes) of the pattern in a LIKE or GLOB
+** operator.
+*/
+#ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
+# define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
+#endif
+
+/*
+** Maximum depth of recursion for triggers.
+**
+** A value of 1 means that a trigger program will not be able to itself
+** fire any triggers. A value of 0 means that no trigger programs at all
+** may be executed.
+*/
+#ifndef SQLITE_MAX_TRIGGER_DEPTH
+# define SQLITE_MAX_TRIGGER_DEPTH 1000
+#endif
+
+/************** End of sqliteLimit.h *****************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/* Disable nuisance warnings on Borland compilers */
+#if defined(__BORLANDC__)
+#pragma warn -rch /* unreachable code */
+#pragma warn -ccc /* Condition is always true or false */
+#pragma warn -aus /* Assigned value is never used */
+#pragma warn -csu /* Comparing signed and unsigned */
+#pragma warn -spa /* Suspicious pointer arithmetic */
+#endif
+
+/*
+** A few places in the code require atomic load/store of aligned
+** integer values.
+*/
+#ifndef __has_extension
+# define __has_extension(x) 0     /* compatibility with non-clang compilers */
+#endif
+#if GCC_VERSION>=4007000 || __has_extension(c_atomic)
+# define SQLITE_ATOMIC_INTRINSICS 1
+# define AtomicLoad(PTR)       __atomic_load_n((PTR),__ATOMIC_RELAXED)
+# define AtomicStore(PTR,VAL)  __atomic_store_n((PTR),(VAL),__ATOMIC_RELAXED)
+#else
+# define SQLITE_ATOMIC_INTRINSICS 0
+# define AtomicLoad(PTR)       (*(PTR))
+# define AtomicStore(PTR,VAL)  (*(PTR) = (VAL))
+#endif
+
+/*
+** Include standard header files as necessary
+*/
+#ifdef HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+
+/*
+** The following macros are used to cast pointers to integers and
+** integers to pointers.  The way you do this varies from one compiler
+** to the next, so we have developed the following set of #if statements
+** to generate appropriate macros for a wide range of compilers.
+**
+** The correct "ANSI" way to do this is to use the intptr_t type.
+** Unfortunately, that typedef is not available on all compilers, or
+** if it is available, it requires an #include of specific headers
+** that vary from one machine to the next.
+**
+** Ticket #3860:  The llvm-gcc-4.2 compiler from Apple chokes on
+** the ((void*)&((char*)0)[X]) construct.  But MSVC chokes on ((void*)(X)).
+** So we have to define the macros in different ways depending on the
+** compiler.
+*/
+#if defined(HAVE_STDINT_H)   /* Use this case if we have ANSI headers */
+# define SQLITE_INT_TO_PTR(X)  ((void*)(intptr_t)(X))
+# define SQLITE_PTR_TO_INT(X)  ((int)(intptr_t)(X))
+#elif defined(__PTRDIFF_TYPE__)  /* This case should work for GCC */
+# define SQLITE_INT_TO_PTR(X)  ((void*)(__PTRDIFF_TYPE__)(X))
+# define SQLITE_PTR_TO_INT(X)  ((int)(__PTRDIFF_TYPE__)(X))
+#elif !defined(__GNUC__)       /* Works for compilers other than LLVM */
+# define SQLITE_INT_TO_PTR(X)  ((void*)&((char*)0)[X])
+# define SQLITE_PTR_TO_INT(X)  ((int)(((char*)X)-(char*)0))
+#else                          /* Generates a warning - but it always works */
+# define SQLITE_INT_TO_PTR(X)  ((void*)(X))
+# define SQLITE_PTR_TO_INT(X)  ((int)(X))
+#endif
+
+/*
+** Macros to hint to the compiler that a function should or should not be
+** inlined.
+*/
+#if defined(__GNUC__)
+#  define SQLITE_NOINLINE  __attribute__((noinline))
+#  define SQLITE_INLINE    __attribute__((always_inline)) inline
+#elif defined(_MSC_VER) && _MSC_VER>=1310
+#  define SQLITE_NOINLINE  __declspec(noinline)
+#  define SQLITE_INLINE    __forceinline
+#else
+#  define SQLITE_NOINLINE
+#  define SQLITE_INLINE
+#endif
+#if defined(SQLITE_COVERAGE_TEST) || defined(__STRICT_ANSI__)
+# undef SQLITE_INLINE
+# define SQLITE_INLINE
+#endif
+
+/*
+** Make sure that the compiler intrinsics we desire are enabled when
+** compiling with an appropriate version of MSVC unless prevented by
+** the SQLITE_DISABLE_INTRINSIC define.
+*/
+#if !defined(SQLITE_DISABLE_INTRINSIC)
+#  if defined(_MSC_VER) && _MSC_VER>=1400
+#    if !defined(_WIN32_WCE)
+#      include <intrin.h>
+#      pragma intrinsic(_byteswap_ushort)
+#      pragma intrinsic(_byteswap_ulong)
+#      pragma intrinsic(_byteswap_uint64)
+#      pragma intrinsic(_ReadWriteBarrier)
+#    else
+#      include <cmnintrin.h>
+#    endif
+#  endif
+#endif
+
+/*
+** Enable SQLITE_USE_SEH by default on MSVC builds.  Only omit
+** SEH support if the -DSQLITE_OMIT_SEH option is given.
+*/
+#if defined(_MSC_VER) && !defined(SQLITE_OMIT_SEH)
+# define SQLITE_USE_SEH 1
+#else
+# undef SQLITE_USE_SEH
+#endif
+
+/*
+** Enable SQLITE_DIRECT_OVERFLOW_READ, unless the build explicitly
+** disables it using -DSQLITE_DIRECT_OVERFLOW_READ=0
+*/
+#if defined(SQLITE_DIRECT_OVERFLOW_READ) && SQLITE_DIRECT_OVERFLOW_READ+1==1
+  /* Disable if -DSQLITE_DIRECT_OVERFLOW_READ=0 */
+# undef SQLITE_DIRECT_OVERFLOW_READ
+#else
+  /* In all other cases, enable */
+# define SQLITE_DIRECT_OVERFLOW_READ 1
+#endif
+
+
+/*
+** The SQLITE_THREADSAFE macro must be defined as 0, 1, or 2.
+** 0 means mutexes are permanently disable and the library is never
+** threadsafe.  1 means the library is serialized which is the highest
+** level of threadsafety.  2 means the library is multithreaded - multiple
+** threads can use SQLite as long as no two threads try to use the same
+** database connection at the same time.
+**
+** Older versions of SQLite used an optional THREADSAFE macro.
+** We support that for legacy.
+**
+** To ensure that the correct value of "THREADSAFE" is reported when querying
+** for compile-time options at runtime (e.g. "PRAGMA compile_options"), this
+** logic is partially replicated in ctime.c. If it is updated here, it should
+** also be updated there.
+*/
+#if !defined(SQLITE_THREADSAFE)
+# if defined(THREADSAFE)
+#   define SQLITE_THREADSAFE THREADSAFE
+# else
+#   define SQLITE_THREADSAFE 1 /* IMP: R-07272-22309 */
+# endif
+#endif
+
+/*
+** Powersafe overwrite is on by default.  But can be turned off using
+** the -DSQLITE_POWERSAFE_OVERWRITE=0 command-line option.
+*/
+#ifndef SQLITE_POWERSAFE_OVERWRITE
+# define SQLITE_POWERSAFE_OVERWRITE 1
+#endif
+
+/*
+** EVIDENCE-OF: R-25715-37072 Memory allocation statistics are enabled by
+** default unless SQLite is compiled with SQLITE_DEFAULT_MEMSTATUS=0 in
+** which case memory allocation statistics are disabled by default.
+*/
+#if !defined(SQLITE_DEFAULT_MEMSTATUS)
+# define SQLITE_DEFAULT_MEMSTATUS 1
+#endif
+
+/*
+** Exactly one of the following macros must be defined in order to
+** specify which memory allocation subsystem to use.
+**
+**     SQLITE_SYSTEM_MALLOC          // Use normal system malloc()
+**     SQLITE_WIN32_MALLOC           // Use Win32 native heap API
+**     SQLITE_ZERO_MALLOC            // Use a stub allocator that always fails
+**     SQLITE_MEMDEBUG               // Debugging version of system malloc()
+**
+** On Windows, if the SQLITE_WIN32_MALLOC_VALIDATE macro is defined and the
+** assert() macro is enabled, each call into the Win32 native heap subsystem
+** will cause HeapValidate to be called.  If heap validation should fail, an
+** assertion will be triggered.
+**
+** If none of the above are defined, then set SQLITE_SYSTEM_MALLOC as
+** the default.
+*/
+#if defined(SQLITE_SYSTEM_MALLOC) \
+  + defined(SQLITE_WIN32_MALLOC) \
+  + defined(SQLITE_ZERO_MALLOC) \
+  + defined(SQLITE_MEMDEBUG)>1
+# error "Two or more of the following compile-time configuration options\
+ are defined but at most one is allowed:\
+ SQLITE_SYSTEM_MALLOC, SQLITE_WIN32_MALLOC, SQLITE_MEMDEBUG,\
+ SQLITE_ZERO_MALLOC"
+#endif
+#if defined(SQLITE_SYSTEM_MALLOC) \
+  + defined(SQLITE_WIN32_MALLOC) \
+  + defined(SQLITE_ZERO_MALLOC) \
+  + defined(SQLITE_MEMDEBUG)==0
+# define SQLITE_SYSTEM_MALLOC 1
+#endif
+
+/*
+** If SQLITE_MALLOC_SOFT_LIMIT is not zero, then try to keep the
+** sizes of memory allocations below this value where possible.
+*/
+#if !defined(SQLITE_MALLOC_SOFT_LIMIT)
+# define SQLITE_MALLOC_SOFT_LIMIT 1024
+#endif
+
+/*
+** We need to define _XOPEN_SOURCE as follows in order to enable
+** recursive mutexes on most Unix systems and fchmod() on OpenBSD.
+** But _XOPEN_SOURCE define causes problems for Mac OS X, so omit
+** it.
+*/
+#if !defined(_XOPEN_SOURCE) && !defined(__DARWIN__) && !defined(__APPLE__)
+#  define _XOPEN_SOURCE 600
+#endif
+
+/*
+** NDEBUG and SQLITE_DEBUG are opposites.  It should always be true that
+** defined(NDEBUG)==!defined(SQLITE_DEBUG).  If this is not currently true,
+** make it true by defining or undefining NDEBUG.
+**
+** Setting NDEBUG makes the code smaller and faster by disabling the
+** assert() statements in the code.  So we want the default action
+** to be for NDEBUG to be set and NDEBUG to be undefined only if SQLITE_DEBUG
+** is set.  Thus NDEBUG becomes an opt-in rather than an opt-out
+** feature.
+*/
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+#if defined(NDEBUG) && defined(SQLITE_DEBUG)
+# undef NDEBUG
+#endif
+
+/*
+** Enable SQLITE_ENABLE_EXPLAIN_COMMENTS if SQLITE_DEBUG is turned on.
+*/
+#if !defined(SQLITE_ENABLE_EXPLAIN_COMMENTS) && defined(SQLITE_DEBUG)
+# define SQLITE_ENABLE_EXPLAIN_COMMENTS 1
+#endif
+
+/*
+** The testcase() macro is used to aid in coverage testing.  When
+** doing coverage testing, the condition inside the argument to
+** testcase() must be evaluated both true and false in order to
+** get full branch coverage.  The testcase() macro is inserted
+** to help ensure adequate test coverage in places where simple
+** condition/decision coverage is inadequate.  For example, testcase()
+** can be used to make sure boundary values are tested.  For
+** bitmask tests, testcase() can be used to make sure each bit
+** is significant and used at least once.  On switch statements
+** where multiple cases go to the same block of code, testcase()
+** can insure that all cases are evaluated.
+*/
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_DEBUG)
+# ifndef SQLITE_AMALGAMATION
+    extern unsigned int sqlite3CoverageCounter;
+# endif
+# define testcase(X)  if( X ){ sqlite3CoverageCounter += (unsigned)__LINE__; }
+#else
+# define testcase(X)
+#endif
+
+/*
+** The TESTONLY macro is used to enclose variable declarations or
+** other bits of code that are needed to support the arguments
+** within testcase() and assert() macros.
+*/
+#if !defined(NDEBUG) || defined(SQLITE_COVERAGE_TEST)
+# define TESTONLY(X)  X
+#else
+# define TESTONLY(X)
+#endif
+
+/*
+** Sometimes we need a small amount of code such as a variable initialization
+** to setup for a later assert() statement.  We do not want this code to
+** appear when assert() is disabled.  The following macro is therefore
+** used to contain that setup code.  The "VVA" acronym stands for
+** "Verification, Validation, and Accreditation".  In other words, the
+** code within VVA_ONLY() will only run during verification processes.
+*/
+#ifndef NDEBUG
+# define VVA_ONLY(X)  X
+#else
+# define VVA_ONLY(X)
+#endif
+
+/*
+** Disable ALWAYS() and NEVER() (make them pass-throughs) for coverage
+** and mutation testing
+*/
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
+# define SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS  1
+#endif
+
+/*
+** The ALWAYS and NEVER macros surround boolean expressions which
+** are intended to always be true or false, respectively.  Such
+** expressions could be omitted from the code completely.  But they
+** are included in a few cases in order to enhance the resilience
+** of SQLite to unexpected behavior - to make the code "self-healing"
+** or "ductile" rather than being "brittle" and crashing at the first
+** hint of unplanned behavior.
+**
+** In other words, ALWAYS and NEVER are added for defensive code.
+**
+** When doing coverage testing ALWAYS and NEVER are hard-coded to
+** be true and false so that the unreachable code they specify will
+** not be counted as untested code.
+*/
+#if defined(SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS)
+# define ALWAYS(X)      (1)
+# define NEVER(X)       (0)
+#elif !defined(NDEBUG)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
+#else
+# define ALWAYS(X)      (X)
+# define NEVER(X)       (X)
+#endif
+
+/*
+** Some conditionals are optimizations only.  In other words, if the
+** conditionals are replaced with a constant 1 (true) or 0 (false) then
+** the correct answer is still obtained, though perhaps not as quickly.
+**
+** The following macros mark these optimizations conditionals.
+*/
+#if defined(SQLITE_MUTATION_TEST)
+# define OK_IF_ALWAYS_TRUE(X)  (1)
+# define OK_IF_ALWAYS_FALSE(X) (0)
+#else
+# define OK_IF_ALWAYS_TRUE(X)  (X)
+# define OK_IF_ALWAYS_FALSE(X) (X)
+#endif
+
+/*
+** Some malloc failures are only possible if SQLITE_TEST_REALLOC_STRESS is
+** defined.  We need to defend against those failures when testing with
+** SQLITE_TEST_REALLOC_STRESS, but we don't want the unreachable branches
+** during a normal build.  The following macro can be used to disable tests
+** that are always false except when SQLITE_TEST_REALLOC_STRESS is set.
+*/
+#if defined(SQLITE_TEST_REALLOC_STRESS)
+# define ONLY_IF_REALLOC_STRESS(X)  (X)
+#elif !defined(NDEBUG)
+# define ONLY_IF_REALLOC_STRESS(X)  ((X)?(assert(0),1):0)
+#else
+# define ONLY_IF_REALLOC_STRESS(X)  (0)
+#endif
+
+/*
+** Declarations used for tracing the operating system interfaces.
+*/
+#if defined(SQLITE_FORCE_OS_TRACE) || defined(SQLITE_TEST) || \
+    (defined(SQLITE_DEBUG) && SQLITE_OS_WIN)
+  extern int sqlite3OSTrace;
+# define OSTRACE(X)          if( sqlite3OSTrace ) sqlite3DebugPrintf X
+# define SQLITE_HAVE_OS_TRACE
+#else
+# define OSTRACE(X)
+# undef  SQLITE_HAVE_OS_TRACE
+#endif
+
+/*
+** Is the sqlite3ErrName() function needed in the build?  Currently,
+** it is needed by "mutex_w32.c" (when debugging), "os_win.c" (when
+** OSTRACE is enabled), and by several "test*.c" files (which are
+** compiled using SQLITE_TEST).
+*/
+#if defined(SQLITE_HAVE_OS_TRACE) || defined(SQLITE_TEST) || \
+    (defined(SQLITE_DEBUG) && SQLITE_OS_WIN)
+# define SQLITE_NEED_ERR_NAME
+#else
+# undef  SQLITE_NEED_ERR_NAME
+#endif
+
+/*
+** SQLITE_ENABLE_EXPLAIN_COMMENTS is incompatible with SQLITE_OMIT_EXPLAIN
+*/
+#ifdef SQLITE_OMIT_EXPLAIN
+# undef SQLITE_ENABLE_EXPLAIN_COMMENTS
+#endif
+
+/*
+** SQLITE_OMIT_VIRTUALTABLE implies SQLITE_OMIT_ALTERTABLE
+*/
+#if defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_ALTERTABLE)
+# define SQLITE_OMIT_ALTERTABLE
+#endif
+
+#define SQLITE_DIGIT_SEPARATOR '_'
+
+/*
+** Return true (non-zero) if the input is an integer that is too large
+** to fit in 32-bits.  This macro is used inside of various testcase()
+** macros to verify that we have tested SQLite for large-file support.
+*/
+#define IS_BIG_INT(X)  (((X)&~(i64)0xffffffff)!=0)
+
+/*
+** The macro unlikely() is a hint that surrounds a boolean
+** expression that is usually false.  Macro likely() surrounds
+** a boolean expression that is usually true.  These hints could,
+** in theory, be used by the compiler to generate better code, but
+** currently they are just comments for human readers.
+*/
+#define likely(X)    (X)
+#define unlikely(X)  (X)
+
+/************** Include hash.h in the middle of sqliteInt.h ******************/
+/************** Begin file hash.h ********************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for the generic hash-table implementation
+** used in SQLite.
+*/
+#ifndef SQLITE_HASH_H
+#define SQLITE_HASH_H
+
+/* Forward declarations of structures. */
+typedef struct Hash Hash;
+typedef struct HashElem HashElem;
+
+/* A complete hash table is an instance of the following structure.
+** The internals of this structure are intended to be opaque -- client
+** code should not attempt to access or modify the fields of this structure
+** directly.  Change this structure only by using the routines below.
+** However, some of the "procedures" and "functions" for modifying and
+** accessing this structure are really macros, so we can't really make
+** this structure opaque.
+**
+** All elements of the hash table are on a single doubly-linked list.
+** Hash.first points to the head of this list.
+**
+** There are Hash.htsize buckets.  Each bucket points to a spot in
+** the global doubly-linked list.  The contents of the bucket are the
+** element pointed to plus the next _ht.count-1 elements in the list.
+**
+** Hash.htsize and Hash.ht may be zero.  In that case lookup is done
+** by a linear search of the global list.  For small tables, the
+** Hash.ht table is never allocated because if there are few elements
+** in the table, it is faster to do a linear search than to manage
+** the hash table.
+*/
+struct Hash {
+  unsigned int htsize;      /* Number of buckets in the hash table */
+  unsigned int count;       /* Number of entries in this table */
+  HashElem *first;          /* The first element of the array */
+  struct _ht {              /* the hash table */
+    unsigned int count;        /* Number of entries with this hash */
+    HashElem *chain;           /* Pointer to first entry with this hash */
+  } *ht;
+};
+
+/* Each element in the hash table is an instance of the following
+** structure.  All elements are stored on a single doubly-linked list.
+**
+** Again, this structure is intended to be opaque, but it can't really
+** be opaque because it is used by macros.
+*/
+struct HashElem {
+  HashElem *next, *prev;       /* Next and previous elements in the table */
+  void *data;                  /* Data associated with this element */
+  const char *pKey;            /* Key associated with this element */
+};
+
+/*
+** Access routines.  To delete, insert a NULL pointer.
+*/
+SQLITE_PRIVATE void sqlite3HashInit(Hash*);
+SQLITE_PRIVATE void *sqlite3HashInsert(Hash*, const char *pKey, void *pData);
+SQLITE_PRIVATE void *sqlite3HashFind(const Hash*, const char *pKey);
+SQLITE_PRIVATE void sqlite3HashClear(Hash*);
+
+/*
+** Macros for looping over all elements of a hash table.  The idiom is
+** like this:
+**
+**   Hash h;
+**   HashElem *p;
+**   ...
+**   for(p=sqliteHashFirst(&h); p; p=sqliteHashNext(p)){
+**     SomeStructure *pData = sqliteHashData(p);
+**     // do something with pData
+**   }
+*/
+#define sqliteHashFirst(H)  ((H)->first)
+#define sqliteHashNext(E)   ((E)->next)
+#define sqliteHashData(E)   ((E)->data)
+/* #define sqliteHashKey(E)    ((E)->pKey) // NOT USED */
+/* #define sqliteHashKeysize(E) ((E)->nKey)  // NOT USED */
+
+/*
+** Number of entries in a hash table
+*/
+#define sqliteHashCount(H)  ((H)->count)
+
+#endif /* SQLITE_HASH_H */
+
+/************** End of hash.h ************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include parse.h in the middle of sqliteInt.h *****************/
+/************** Begin file parse.h *******************************************/
+#define TK_SEMI                             1
+#define TK_EXPLAIN                          2
+#define TK_QUERY                            3
+#define TK_PLAN                             4
+#define TK_BEGIN                            5
+#define TK_TRANSACTION                      6
+#define TK_DEFERRED                         7
+#define TK_IMMEDIATE                        8
+#define TK_EXCLUSIVE                        9
+#define TK_COMMIT                          10
+#define TK_END                             11
+#define TK_ROLLBACK                        12
+#define TK_SAVEPOINT                       13
+#define TK_RELEASE                         14
+#define TK_TO                              15
+#define TK_TABLE                           16
+#define TK_CREATE                          17
+#define TK_IF                              18
+#define TK_NOT                             19
+#define TK_EXISTS                          20
+#define TK_TEMP                            21
+#define TK_LP                              22
+#define TK_RP                              23
+#define TK_AS                              24
+#define TK_COMMA                           25
+#define TK_WITHOUT                         26
+#define TK_ABORT                           27
+#define TK_ACTION                          28
+#define TK_AFTER                           29
+#define TK_ANALYZE                         30
+#define TK_ASC                             31
+#define TK_ATTACH                          32
+#define TK_BEFORE                          33
+#define TK_BY                              34
+#define TK_CASCADE                         35
+#define TK_CAST                            36
+#define TK_CONFLICT                        37
+#define TK_DATABASE                        38
+#define TK_DESC                            39
+#define TK_DETACH                          40
+#define TK_EACH                            41
+#define TK_FAIL                            42
+#define TK_OR                              43
+#define TK_AND                             44
+#define TK_IS                              45
+#define TK_ISNOT                           46
+#define TK_MATCH                           47
+#define TK_LIKE_KW                         48
+#define TK_BETWEEN                         49
+#define TK_IN                              50
+#define TK_ISNULL                          51
+#define TK_NOTNULL                         52
+#define TK_NE                              53
+#define TK_EQ                              54
+#define TK_GT                              55
+#define TK_LE                              56
+#define TK_LT                              57
+#define TK_GE                              58
+#define TK_ESCAPE                          59
+#define TK_ID                              60
+#define TK_COLUMNKW                        61
+#define TK_DO                              62
+#define TK_FOR                             63
+#define TK_IGNORE                          64
+#define TK_INITIALLY                       65
+#define TK_INSTEAD                         66
+#define TK_NO                              67
+#define TK_KEY                             68
+#define TK_OF                              69
+#define TK_OFFSET                          70
+#define TK_PRAGMA                          71
+#define TK_RAISE                           72
+#define TK_RECURSIVE                       73
+#define TK_REPLACE                         74
+#define TK_RESTRICT                        75
+#define TK_ROW                             76
+#define TK_ROWS                            77
+#define TK_TRIGGER                         78
+#define TK_VACUUM                          79
+#define TK_VIEW                            80
+#define TK_VIRTUAL                         81
+#define TK_WITH                            82
+#define TK_NULLS                           83
+#define TK_FIRST                           84
+#define TK_LAST                            85
+#define TK_CURRENT                         86
+#define TK_FOLLOWING                       87
+#define TK_PARTITION                       88
+#define TK_PRECEDING                       89
+#define TK_RANGE                           90
+#define TK_UNBOUNDED                       91
+#define TK_EXCLUDE                         92
+#define TK_GROUPS                          93
+#define TK_OTHERS                          94
+#define TK_TIES                            95
+#define TK_GENERATED                       96
+#define TK_ALWAYS                          97
+#define TK_MATERIALIZED                    98
+#define TK_REINDEX                         99
+#define TK_RENAME                         100
+#define TK_CTIME_KW                       101
+#define TK_ANY                            102
+#define TK_BITAND                         103
+#define TK_BITOR                          104
+#define TK_LSHIFT                         105
+#define TK_RSHIFT                         106
+#define TK_PLUS                           107
+#define TK_MINUS                          108
+#define TK_STAR                           109
+#define TK_SLASH                          110
+#define TK_REM                            111
+#define TK_CONCAT                         112
+#define TK_PTR                            113
+#define TK_COLLATE                        114
+#define TK_BITNOT                         115
+#define TK_ON                             116
+#define TK_INDEXED                        117
+#define TK_STRING                         118
+#define TK_JOIN_KW                        119
+#define TK_CONSTRAINT                     120
+#define TK_DEFAULT                        121
+#define TK_NULL                           122
+#define TK_PRIMARY                        123
+#define TK_UNIQUE                         124
+#define TK_CHECK                          125
+#define TK_REFERENCES                     126
+#define TK_AUTOINCR                       127
+#define TK_INSERT                         128
+#define TK_DELETE                         129
+#define TK_UPDATE                         130
+#define TK_SET                            131
+#define TK_DEFERRABLE                     132
+#define TK_FOREIGN                        133
+#define TK_DROP                           134
+#define TK_UNION                          135
+#define TK_ALL                            136
+#define TK_EXCEPT                         137
+#define TK_INTERSECT                      138
+#define TK_SELECT                         139
+#define TK_VALUES                         140
+#define TK_DISTINCT                       141
+#define TK_DOT                            142
+#define TK_FROM                           143
+#define TK_JOIN                           144
+#define TK_USING                          145
+#define TK_ORDER                          146
+#define TK_GROUP                          147
+#define TK_HAVING                         148
+#define TK_LIMIT                          149
+#define TK_WHERE                          150
+#define TK_RETURNING                      151
+#define TK_INTO                           152
+#define TK_NOTHING                        153
+#define TK_FLOAT                          154
+#define TK_BLOB                           155
+#define TK_INTEGER                        156
+#define TK_VARIABLE                       157
+#define TK_CASE                           158
+#define TK_WHEN                           159
+#define TK_THEN                           160
+#define TK_ELSE                           161
+#define TK_INDEX                          162
+#define TK_ALTER                          163
+#define TK_ADD                            164
+#define TK_WINDOW                         165
+#define TK_OVER                           166
+#define TK_FILTER                         167
+#define TK_COLUMN                         168
+#define TK_AGG_FUNCTION                   169
+#define TK_AGG_COLUMN                     170
+#define TK_TRUEFALSE                      171
+#define TK_FUNCTION                       172
+#define TK_UPLUS                          173
+#define TK_UMINUS                         174
+#define TK_TRUTH                          175
+#define TK_REGISTER                       176
+#define TK_VECTOR                         177
+#define TK_SELECT_COLUMN                  178
+#define TK_IF_NULL_ROW                    179
+#define TK_ASTERISK                       180
+#define TK_SPAN                           181
+#define TK_ERROR                          182
+#define TK_QNUMBER                        183
+#define TK_SPACE                          184
+#define TK_COMMENT                        185
+#define TK_ILLEGAL                        186
+
+/************** End of parse.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <stddef.h>
+#include <ctype.h>
+
+/*
+** Use a macro to replace memcpy() if compiled with SQLITE_INLINE_MEMCPY.
+** This allows better measurements of where memcpy() is used when running
+** cachegrind.  But this macro version of memcpy() is very slow so it
+** should not be used in production.  This is a performance measurement
+** hack only.
+*/
+#ifdef SQLITE_INLINE_MEMCPY
+# define memcpy(D,S,N) {char*xxd=(char*)(D);const char*xxs=(const char*)(S);\
+                        int xxn=(N);while(xxn-->0)*(xxd++)=*(xxs++);}
+#endif
+
+/*
+** If compiling for a processor that lacks floating point support,
+** substitute integer for floating-point
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define double sqlite_int64
+# define float sqlite_int64
+# define fabs(X) ((X)<0?-(X):(X))
+# define sqlite3IsOverflow(X) 0
+# ifndef SQLITE_BIG_DBL
+#   define SQLITE_BIG_DBL (((sqlite3_int64)1)<<50)
+# endif
+# define SQLITE_OMIT_DATETIME_FUNCS 1
+# define SQLITE_OMIT_TRACE 1
+# undef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+# undef SQLITE_HAVE_ISNAN
+#endif
+#ifndef SQLITE_BIG_DBL
+# define SQLITE_BIG_DBL (1e99)
+#endif
+
+/*
+** OMIT_TEMPDB is set to 1 if SQLITE_OMIT_TEMPDB is defined, or 0
+** afterward. Having this macro allows us to cause the C compiler
+** to omit code used by TEMP tables without messy #ifndef statements.
+*/
+#ifdef SQLITE_OMIT_TEMPDB
+#define OMIT_TEMPDB 1
+#else
+#define OMIT_TEMPDB 0
+#endif
+
+/*
+** The "file format" number is an integer that is incremented whenever
+** the VDBE-level file format changes.  The following macros define the
+** the default file format for new databases and the maximum file format
+** that the library can read.
+*/
+#define SQLITE_MAX_FILE_FORMAT 4
+#ifndef SQLITE_DEFAULT_FILE_FORMAT
+# define SQLITE_DEFAULT_FILE_FORMAT 4
+#endif
+
+/*
+** Determine whether triggers are recursive by default.  This can be
+** changed at run-time using a pragma.
+*/
+#ifndef SQLITE_DEFAULT_RECURSIVE_TRIGGERS
+# define SQLITE_DEFAULT_RECURSIVE_TRIGGERS 0
+#endif
+
+/*
+** Provide a default value for SQLITE_TEMP_STORE in case it is not specified
+** on the command-line
+*/
+#ifndef SQLITE_TEMP_STORE
+# define SQLITE_TEMP_STORE 1
+#endif
+
+/*
+** If no value has been provided for SQLITE_MAX_WORKER_THREADS, or if
+** SQLITE_TEMP_STORE is set to 3 (never use temporary files), set it
+** to zero.
+*/
+#if SQLITE_TEMP_STORE==3 || SQLITE_THREADSAFE==0
+# undef SQLITE_MAX_WORKER_THREADS
+# define SQLITE_MAX_WORKER_THREADS 0
+#endif
+#ifndef SQLITE_MAX_WORKER_THREADS
+# define SQLITE_MAX_WORKER_THREADS 8
+#endif
+#ifndef SQLITE_DEFAULT_WORKER_THREADS
+# define SQLITE_DEFAULT_WORKER_THREADS 0
+#endif
+#if SQLITE_DEFAULT_WORKER_THREADS>SQLITE_MAX_WORKER_THREADS
+# undef SQLITE_MAX_WORKER_THREADS
+# define SQLITE_MAX_WORKER_THREADS SQLITE_DEFAULT_WORKER_THREADS
+#endif
+
+/*
+** The default initial allocation for the pagecache when using separate
+** pagecaches for each database connection.  A positive number is the
+** number of pages.  A negative number N translations means that a buffer
+** of -1024*N bytes is allocated and used for as many pages as it will hold.
+**
+** The default value of "20" was chosen to minimize the run-time of the
+** speedtest1 test program with options: --shrink-memory --reprepare
+*/
+#ifndef SQLITE_DEFAULT_PCACHE_INITSZ
+# define SQLITE_DEFAULT_PCACHE_INITSZ 20
+#endif
+
+/*
+** Default value for the SQLITE_CONFIG_SORTERREF_SIZE option.
+*/
+#ifndef SQLITE_DEFAULT_SORTERREF_SIZE
+# define SQLITE_DEFAULT_SORTERREF_SIZE 0x7fffffff
+#endif
+
+/*
+** The compile-time options SQLITE_MMAP_READWRITE and
+** SQLITE_ENABLE_BATCH_ATOMIC_WRITE are not compatible with one another.
+** You must choose one or the other (or neither) but not both.
+*/
+#if defined(SQLITE_MMAP_READWRITE) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+#error Cannot use both SQLITE_MMAP_READWRITE and SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+#endif
+
+/*
+** GCC does not define the offsetof() macro so we'll have to do it
+** ourselves.
+*/
+#ifndef offsetof
+#define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))
+#endif
+
+/*
+** Macros to compute minimum and maximum of two numbers.
+*/
+#ifndef MIN
+# define MIN(A,B) ((A)<(B)?(A):(B))
+#endif
+#ifndef MAX
+# define MAX(A,B) ((A)>(B)?(A):(B))
+#endif
+
+/*
+** Swap two objects of type TYPE.
+*/
+#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
+
+/*
+** Check to see if this machine uses EBCDIC.  (Yes, believe it or
+** not, there are still machines out there that use EBCDIC.)
+*/
+#if 'A' == '\301'
+# define SQLITE_EBCDIC 1
+#else
+# define SQLITE_ASCII 1
+#endif
+
+/*
+** Integers of known sizes.  These typedefs might change for architectures
+** where the sizes very.  Preprocessor macros are available so that the
+** types can be conveniently redefined at compile-type.  Like this:
+**
+**         cc '-DUINTPTR_TYPE=long long int' ...
+*/
+#ifndef UINT32_TYPE
+# ifdef HAVE_UINT32_T
+#  define UINT32_TYPE uint32_t
+# else
+#  define UINT32_TYPE unsigned int
+# endif
+#endif
+#ifndef UINT16_TYPE
+# ifdef HAVE_UINT16_T
+#  define UINT16_TYPE uint16_t
+# else
+#  define UINT16_TYPE unsigned short int
+# endif
+#endif
+#ifndef INT16_TYPE
+# ifdef HAVE_INT16_T
+#  define INT16_TYPE int16_t
+# else
+#  define INT16_TYPE short int
+# endif
+#endif
+#ifndef UINT8_TYPE
+# ifdef HAVE_UINT8_T
+#  define UINT8_TYPE uint8_t
+# else
+#  define UINT8_TYPE unsigned char
+# endif
+#endif
+#ifndef INT8_TYPE
+# ifdef HAVE_INT8_T
+#  define INT8_TYPE int8_t
+# else
+#  define INT8_TYPE signed char
+# endif
+#endif
+typedef sqlite_int64 i64;          /* 8-byte signed integer */
+typedef sqlite_uint64 u64;         /* 8-byte unsigned integer */
+typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
+typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
+typedef INT16_TYPE i16;            /* 2-byte signed integer */
+typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
+typedef INT8_TYPE i8;              /* 1-byte signed integer */
+
+/*
+** SQLITE_MAX_U32 is a u64 constant that is the maximum u64 value
+** that can be stored in a u32 without loss of data.  The value
+** is 0x00000000ffffffff.  But because of quirks of some compilers, we
+** have to specify the value in the less intuitive manner shown:
+*/
+#define SQLITE_MAX_U32  ((((u64)1)<<32)-1)
+
+/*
+** The datatype used to store estimates of the number of rows in a
+** table or index.
+*/
+typedef u64 tRowcnt;
+
+/*
+** Estimated quantities used for query planning are stored as 16-bit
+** logarithms.  For quantity X, the value stored is 10*log2(X).  This
+** gives a possible range of values of approximately 1.0e986 to 1e-986.
+** But the allowed values are "grainy".  Not every value is representable.
+** For example, quantities 16 and 17 are both represented by a LogEst
+** of 40.  However, since LogEst quantities are suppose to be estimates,
+** not exact values, this imprecision is not a problem.
+**
+** "LogEst" is short for "Logarithmic Estimate".
+**
+** Examples:
+**      1 -> 0              20 -> 43          10000 -> 132
+**      2 -> 10             25 -> 46          25000 -> 146
+**      3 -> 16            100 -> 66        1000000 -> 199
+**      4 -> 20           1000 -> 99        1048576 -> 200
+**     10 -> 33           1024 -> 100    4294967296 -> 320
+**
+** The LogEst can be negative to indicate fractional values.
+** Examples:
+**
+**    0.5 -> -10           0.1 -> -33        0.0625 -> -40
+*/
+typedef INT16_TYPE LogEst;
+#define LOGEST_MIN (-32768)
+#define LOGEST_MAX (32767)
+
+/*
+** Set the SQLITE_PTRSIZE macro to the number of bytes in a pointer
+*/
+#ifndef SQLITE_PTRSIZE
+# if defined(__SIZEOF_POINTER__)
+#   define SQLITE_PTRSIZE __SIZEOF_POINTER__
+# elif defined(i386)     || defined(__i386__)   || defined(_M_IX86) ||    \
+       defined(_M_ARM)   || defined(__arm__)    || defined(__x86)   ||    \
+      (defined(__APPLE__) && defined(__ppc__)) ||                         \
+      (defined(__TOS_AIX__) && !defined(__64BIT__))
+#   define SQLITE_PTRSIZE 4
+# else
+#   define SQLITE_PTRSIZE 8
+# endif
+#endif
+
+/* The uptr type is an unsigned integer large enough to hold a pointer
+*/
+#if defined(HAVE_STDINT_H)
+  typedef uintptr_t uptr;
+#elif SQLITE_PTRSIZE==4
+  typedef u32 uptr;
+#else
+  typedef u64 uptr;
+#endif
+
+/*
+** The SQLITE_WITHIN(P,S,E) macro checks to see if pointer P points to
+** something between S (inclusive) and E (exclusive).
+**
+** In other words, S is a buffer and E is a pointer to the first byte after
+** the end of buffer S.  This macro returns true if P points to something
+** contained within the buffer S.
+*/
+#define SQLITE_WITHIN(P,S,E)   (((uptr)(P)>=(uptr)(S))&&((uptr)(P)<(uptr)(E)))
+
+/*
+** P is one byte past the end of a large buffer. Return true if a span of bytes
+** between S..E crosses the end of that buffer.  In other words, return true
+** if the sub-buffer S..E-1 overflows the buffer whose last byte is P-1.
+**
+** S is the start of the span.  E is one byte past the end of end of span.
+**
+**                        P
+**     |-----------------|                FALSE
+**               |-------|
+**               S        E
+**
+**                        P
+**     |-----------------|
+**                    |-------|           TRUE
+**                    S        E
+**
+**                        P
+**     |-----------------|
+**                        |-------|       FALSE
+**                        S        E
+*/
+#define SQLITE_OVERFLOW(P,S,E) (((uptr)(S)<(uptr)(P))&&((uptr)(E)>(uptr)(P)))
+
+/*
+** Macros to determine whether the machine is big or little endian,
+** and whether or not that determination is run-time or compile-time.
+**
+** For best performance, an attempt is made to guess at the byte-order
+** using C-preprocessor macros.  If that is unsuccessful, or if
+** -DSQLITE_BYTEORDER=0 is set, then byte-order is determined
+** at run-time.
+**
+** If you are building SQLite on some obscure platform for which the
+** following ifdef magic does not work, you can always include either:
+**
+**    -DSQLITE_BYTEORDER=1234
+**
+** or
+**
+**    -DSQLITE_BYTEORDER=4321
+**
+** to cause the build to work for little-endian or big-endian processors,
+** respectively.
+*/
+#ifndef SQLITE_BYTEORDER  /* Replicate changes at tag-20230904a */
+# if defined(__BYTE_ORDER__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
+#   define SQLITE_BYTEORDER 4321
+# elif defined(__BYTE_ORDER__) && __BYTE_ORDER__==__ORDER_LITTLE_ENDIAN__
+#   define SQLITE_BYTEORDER 1234
+# elif defined(__BIG_ENDIAN__) && __BIG_ENDIAN__==1
+#   define SQLITE_BYTEORDER 4321
+# elif defined(i386)    || defined(__i386__)      || defined(_M_IX86) ||    \
+     defined(__x86_64)  || defined(__x86_64__)    || defined(_M_X64)  ||    \
+     defined(_M_AMD64)  || defined(_M_ARM)        || defined(__x86)   ||    \
+     defined(__ARMEL__) || defined(__AARCH64EL__) || defined(_M_ARM64)
+#   define SQLITE_BYTEORDER 1234
+# elif defined(sparc)   || defined(__ARMEB__)     || defined(__AARCH64EB__)
+#   define SQLITE_BYTEORDER 4321
+# else
+#   define SQLITE_BYTEORDER 0
+# endif
+#endif
+#if SQLITE_BYTEORDER==4321
+# define SQLITE_BIGENDIAN    1
+# define SQLITE_LITTLEENDIAN 0
+# define SQLITE_UTF16NATIVE  SQLITE_UTF16BE
+#elif SQLITE_BYTEORDER==1234
+# define SQLITE_BIGENDIAN    0
+# define SQLITE_LITTLEENDIAN 1
+# define SQLITE_UTF16NATIVE  SQLITE_UTF16LE
+#else
+# ifdef SQLITE_AMALGAMATION
+  const int sqlite3one = 1;
+# else
+  extern const int sqlite3one;
+# endif
+# define SQLITE_BIGENDIAN    (*(char *)(&sqlite3one)==0)
+# define SQLITE_LITTLEENDIAN (*(char *)(&sqlite3one)==1)
+# define SQLITE_UTF16NATIVE  (SQLITE_BIGENDIAN?SQLITE_UTF16BE:SQLITE_UTF16LE)
+#endif
+
+/*
+** Constants for the largest and smallest possible 64-bit signed integers.
+** These macros are designed to work correctly on both 32-bit and 64-bit
+** compilers.
+*/
+#define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
+#define LARGEST_UINT64 (0xffffffff|(((u64)0xffffffff)<<32))
+#define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
+
+/*
+** Round up a number to the next larger multiple of 8.  This is used
+** to force 8-byte alignment on 64-bit architectures.
+**
+** ROUND8() always does the rounding, for any argument.
+**
+** ROUND8P() assumes that the argument is already an integer number of
+** pointers in size, and so it is a no-op on systems where the pointer
+** size is 8.
+*/
+#define ROUND8(x)     (((x)+7)&~7)
+#if SQLITE_PTRSIZE==8
+# define ROUND8P(x)   (x)
+#else
+# define ROUND8P(x)   (((x)+7)&~7)
+#endif
+
+/*
+** Round down to the nearest multiple of 8
+*/
+#define ROUNDDOWN8(x) ((x)&~7)
+
+/*
+** Assert that the pointer X is aligned to an 8-byte boundary.  This
+** macro is used only within assert() to verify that the code gets
+** all alignment restrictions correct.
+**
+** Except, if SQLITE_4_BYTE_ALIGNED_MALLOC is defined, then the
+** underlying malloc() implementation might return us 4-byte aligned
+** pointers.  In that case, only verify 4-byte alignment.
+*/
+#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&3)==0)
+#else
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&7)==0)
+#endif
+
+/*
+** Disable MMAP on platforms where it is known to not work
+*/
+#if defined(__OpenBSD__) || defined(__QNXNTO__)
+# undef SQLITE_MAX_MMAP_SIZE
+# define SQLITE_MAX_MMAP_SIZE 0
+#endif
+
+/*
+** Default maximum size of memory used by memory-mapped I/O in the VFS
+*/
+#ifdef __APPLE__
+# include <TargetConditionals.h>
+#endif
+#ifndef SQLITE_MAX_MMAP_SIZE
+# if defined(__linux__) \
+  || defined(_WIN32) \
+  || (defined(__APPLE__) && defined(__MACH__)) \
+  || defined(__sun) \
+  || defined(__FreeBSD__) \
+  || defined(__DragonFly__)
+#   define SQLITE_MAX_MMAP_SIZE 0x7fff0000  /* 2147418112 */
+# else
+#   define SQLITE_MAX_MMAP_SIZE 0
+# endif
+#endif
+
+/*
+** The default MMAP_SIZE is zero on all platforms.  Or, even if a larger
+** default MMAP_SIZE is specified at compile-time, make sure that it does
+** not exceed the maximum mmap size.
+*/
+#ifndef SQLITE_DEFAULT_MMAP_SIZE
+# define SQLITE_DEFAULT_MMAP_SIZE 0
+#endif
+#if SQLITE_DEFAULT_MMAP_SIZE>SQLITE_MAX_MMAP_SIZE
+# undef SQLITE_DEFAULT_MMAP_SIZE
+# define SQLITE_DEFAULT_MMAP_SIZE SQLITE_MAX_MMAP_SIZE
+#endif
+
+/*
+** TREETRACE_ENABLED will be either 1 or 0 depending on whether or not
+** the Abstract Syntax Tree tracing logic is turned on.
+*/
+#if !defined(SQLITE_AMALGAMATION)
+SQLITE_PRIVATE u32 sqlite3TreeTrace;
+#endif
+#if defined(SQLITE_DEBUG) \
+    && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_SELECTTRACE) \
+                             || defined(SQLITE_ENABLE_TREETRACE))
+# define TREETRACE_ENABLED 1
+# define TREETRACE(K,P,S,X)  \
+  if(sqlite3TreeTrace&(K))   \
+    sqlite3DebugPrintf("%u/%d/%p: ",(S)->selId,(P)->addrExplain,(S)),\
+    sqlite3DebugPrintf X
+#else
+# define TREETRACE(K,P,S,X)
+# define TREETRACE_ENABLED 0
+#endif
+
+/* TREETRACE flag meanings:
+**
+**   0x00000001     Beginning and end of SELECT processing
+**   0x00000002     WHERE clause processing
+**   0x00000004     Query flattener
+**   0x00000008     Result-set wildcard expansion
+**   0x00000010     Query name resolution
+**   0x00000020     Aggregate analysis
+**   0x00000040     Window functions
+**   0x00000080     Generated column names
+**   0x00000100     Move HAVING terms into WHERE
+**   0x00000200     Count-of-view optimization
+**   0x00000400     Compound SELECT processing
+**   0x00000800     Drop superfluous ORDER BY
+**   0x00001000     LEFT JOIN simplifies to JOIN
+**   0x00002000     Constant propagation
+**   0x00004000     Push-down optimization
+**   0x00008000     After all FROM-clause analysis
+**   0x00010000     Beginning of DELETE/INSERT/UPDATE processing
+**   0x00020000     Transform DISTINCT into GROUP BY
+**   0x00040000     SELECT tree dump after all code has been generated
+**   0x00080000     NOT NULL strength reduction
+*/
+
+/*
+** Macros for "wheretrace"
+*/
+SQLITE_PRIVATE u32 sqlite3WhereTrace;
+#if defined(SQLITE_DEBUG) \
+    && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_WHERETRACE))
+# define WHERETRACE(K,X)  if(sqlite3WhereTrace&(K)) sqlite3DebugPrintf X
+# define WHERETRACE_ENABLED 1
+#else
+# define WHERETRACE(K,X)
+#endif
+
+/*
+** Bits for the sqlite3WhereTrace mask:
+**
+** (---any--)   Top-level block structure
+** 0x-------F   High-level debug messages
+** 0x----FFF-   More detail
+** 0xFFFF----   Low-level debug messages
+**
+** 0x00000001   Code generation
+** 0x00000002   Solver (Use 0x40000 for less detail)
+** 0x00000004   Solver costs
+** 0x00000008   WhereLoop inserts
+**
+** 0x00000010   Display sqlite3_index_info xBestIndex calls
+** 0x00000020   Range an equality scan metrics
+** 0x00000040   IN operator decisions
+** 0x00000080   WhereLoop cost adjustments
+** 0x00000100
+** 0x00000200   Covering index decisions
+** 0x00000400   OR optimization
+** 0x00000800   Index scanner
+** 0x00001000   More details associated with code generation
+** 0x00002000
+** 0x00004000   Show all WHERE terms at key points
+** 0x00008000   Show the full SELECT statement at key places
+**
+** 0x00010000   Show more detail when printing WHERE terms
+** 0x00020000   Show WHERE terms returned from whereScanNext()
+** 0x00040000   Solver overview messages
+** 0x00080000   Star-query heuristic
+*/
+
+
+/*
+** An instance of the following structure is used to store the busy-handler
+** callback for a given sqlite handle.
+**
+** The sqlite.busyHandler member of the sqlite struct contains the busy
+** callback for the database handle. Each pager opened via the sqlite
+** handle is passed a pointer to sqlite.busyHandler. The busy-handler
+** callback is currently invoked only from within pager.c.
+*/
+typedef struct BusyHandler BusyHandler;
+struct BusyHandler {
+  int (*xBusyHandler)(void *,int);  /* The busy callback */
+  void *pBusyArg;                   /* First arg to busy callback */
+  int nBusy;                        /* Incremented with each busy call */
+};
+
+/*
+** Name of table that holds the database schema.
+**
+** The PREFERRED names are used wherever possible.  But LEGACY is also
+** used for backwards compatibility.
+**
+**  1.  Queries can use either the PREFERRED or the LEGACY names
+**  2.  The sqlite3_set_authorizer() callback uses the LEGACY name
+**  3.  The PRAGMA table_list statement uses the PREFERRED name
+**
+** The LEGACY names are stored in the internal symbol hash table
+** in support of (2).  Names are translated using sqlite3PreferredTableName()
+** for (3).  The sqlite3FindTable() function takes care of translating
+** names for (1).
+**
+** Note that "sqlite_temp_schema" can also be called "temp.sqlite_schema".
+*/
+#define LEGACY_SCHEMA_TABLE          "sqlite_master"
+#define LEGACY_TEMP_SCHEMA_TABLE     "sqlite_temp_master"
+#define PREFERRED_SCHEMA_TABLE       "sqlite_schema"
+#define PREFERRED_TEMP_SCHEMA_TABLE  "sqlite_temp_schema"
+
+
+/*
+** The root-page of the schema table.
+*/
+#define SCHEMA_ROOT    1
+
+/*
+** The name of the schema table.  The name is different for TEMP.
+*/
+#define SCHEMA_TABLE(x) \
+    ((!OMIT_TEMPDB)&&(x==1)?LEGACY_TEMP_SCHEMA_TABLE:LEGACY_SCHEMA_TABLE)
+
+/*
+** A convenience macro that returns the number of elements in
+** an array.
+*/
+#define ArraySize(X)    ((int)(sizeof(X)/sizeof(X[0])))
+
+/*
+** Determine if the argument is a power of two
+*/
+#define IsPowerOfTwo(X) (((X)&((X)-1))==0)
+
+/*
+** The following value as a destructor means to use sqlite3DbFree().
+** The sqlite3DbFree() routine requires two parameters instead of the
+** one parameter that destructors normally want.  So we have to introduce
+** this magic value that the code knows to handle differently.  Any
+** pointer will work here as long as it is distinct from SQLITE_STATIC
+** and SQLITE_TRANSIENT.
+*/
+#define SQLITE_DYNAMIC   ((sqlite3_destructor_type)sqlite3OomClear)
+
+/*
+** When SQLITE_OMIT_WSD is defined, it means that the target platform does
+** not support Writable Static Data (WSD) such as global and static variables.
+** All variables must either be on the stack or dynamically allocated from
+** the heap.  When WSD is unsupported, the variable declarations scattered
+** throughout the SQLite code must become constants instead.  The SQLITE_WSD
+** macro is used for this purpose.  And instead of referencing the variable
+** directly, we use its constant as a key to lookup the run-time allocated
+** buffer that holds real variable.  The constant is also the initializer
+** for the run-time allocated buffer.
+**
+** In the usual case where WSD is supported, the SQLITE_WSD and GLOBAL
+** macros become no-ops and have zero performance impact.
+*/
+#ifdef SQLITE_OMIT_WSD
+  #define SQLITE_WSD const
+  #define GLOBAL(t,v) (*(t*)sqlite3_wsd_find((void*)&(v), sizeof(v)))
+  #define sqlite3GlobalConfig GLOBAL(struct Sqlite3Config, sqlite3Config)
+SQLITE_API int sqlite3_wsd_init(int N, int J);
+SQLITE_API void *sqlite3_wsd_find(void *K, int L);
+#else
+  #define SQLITE_WSD
+  #define GLOBAL(t,v) v
+  #define sqlite3GlobalConfig sqlite3Config
+#endif
+
+/*
+** The following macros are used to suppress compiler warnings and to
+** make it clear to human readers when a function parameter is deliberately
+** left unused within the body of a function. This usually happens when
+** a function is called via a function pointer. For example the
+** implementation of an SQL aggregate step callback may not use the
+** parameter indicating the number of arguments passed to the aggregate,
+** if it knows that this is enforced elsewhere.
+**
+** When a function parameter is not used at all within the body of a function,
+** it is generally named "NotUsed" or "NotUsed2" to make things even clearer.
+** However, these macros may also be used to suppress warnings related to
+** parameters that may or may not be used depending on compilation options.
+** For example those parameters only used in assert() statements. In these
+** cases the parameters are named as per the usual conventions.
+*/
+#define UNUSED_PARAMETER(x) (void)(x)
+#define UNUSED_PARAMETER2(x,y) UNUSED_PARAMETER(x),UNUSED_PARAMETER(y)
+
+/*
+** Forward references to structures
+*/
+typedef struct AggInfo AggInfo;
+typedef struct AuthContext AuthContext;
+typedef struct AutoincInfo AutoincInfo;
+typedef struct Bitvec Bitvec;
+typedef struct CollSeq CollSeq;
+typedef struct Column Column;
+typedef struct Cte Cte;
+typedef struct CteUse CteUse;
+typedef struct Db Db;
+typedef struct DbClientData DbClientData;
+typedef struct DbFixer DbFixer;
+typedef struct Schema Schema;
+typedef struct Expr Expr;
+typedef struct ExprList ExprList;
+typedef struct FKey FKey;
+typedef struct FpDecode FpDecode;
+typedef struct FuncDestructor FuncDestructor;
+typedef struct FuncDef FuncDef;
+typedef struct FuncDefHash FuncDefHash;
+typedef struct IdList IdList;
+typedef struct Index Index;
+typedef struct IndexedExpr IndexedExpr;
+typedef struct IndexSample IndexSample;
+typedef struct KeyClass KeyClass;
+typedef struct KeyInfo KeyInfo;
+typedef struct Lookaside Lookaside;
+typedef struct LookasideSlot LookasideSlot;
+typedef struct Module Module;
+typedef struct NameContext NameContext;
+typedef struct OnOrUsing OnOrUsing;
+typedef struct Parse Parse;
+typedef struct ParseCleanup ParseCleanup;
+typedef struct PreUpdate PreUpdate;
+typedef struct PrintfArguments PrintfArguments;
+typedef struct RCStr RCStr;
+typedef struct RenameToken RenameToken;
+typedef struct Returning Returning;
+typedef struct RowSet RowSet;
+typedef struct Savepoint Savepoint;
+typedef struct Select Select;
+typedef struct SQLiteThread SQLiteThread;
+typedef struct SelectDest SelectDest;
+typedef struct Subquery Subquery;
+typedef struct SrcItem SrcItem;
+typedef struct SrcList SrcList;
+typedef struct sqlite3_str StrAccum; /* Internal alias for sqlite3_str */
+typedef struct Table Table;
+typedef struct TableLock TableLock;
+typedef struct Token Token;
+typedef struct TreeView TreeView;
+typedef struct Trigger Trigger;
+typedef struct TriggerPrg TriggerPrg;
+typedef struct TriggerStep TriggerStep;
+typedef struct UnpackedRecord UnpackedRecord;
+typedef struct Upsert Upsert;
+typedef struct VTable VTable;
+typedef struct VtabCtx VtabCtx;
+typedef struct Walker Walker;
+typedef struct WhereInfo WhereInfo;
+typedef struct Window Window;
+typedef struct With With;
+
+
+/*
+** The bitmask datatype defined below is used for various optimizations.
+**
+** Changing this from a 64-bit to a 32-bit type limits the number of
+** tables in a join to 32 instead of 64.  But it also reduces the size
+** of the library by 738 bytes on ix86.
+*/
+#ifdef SQLITE_BITMASK_TYPE
+  typedef SQLITE_BITMASK_TYPE Bitmask;
+#else
+  typedef u64 Bitmask;
+#endif
+
+/*
+** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
+*/
+#define BMS  ((int)(sizeof(Bitmask)*8))
+
+/*
+** A bit in a Bitmask
+*/
+#define MASKBIT(n)    (((Bitmask)1)<<(n))
+#define MASKBIT64(n)  (((u64)1)<<(n))
+#define MASKBIT32(n)  (((unsigned int)1)<<(n))
+#define SMASKBIT32(n) ((n)<=31?((unsigned int)1)<<(n):0)
+#define ALLBITS       ((Bitmask)-1)
+#define TOPBIT        (((Bitmask)1)<<(BMS-1))
+
+/* A VList object records a mapping between parameters/variables/wildcards
+** in the SQL statement (such as $abc, @pqr, or :xyz) and the integer
+** variable number associated with that parameter.  See the format description
+** on the sqlite3VListAdd() routine for more information.  A VList is really
+** just an array of integers.
+*/
+typedef int VList;
+
+/*
+** Defer sourcing vdbe.h and btree.h until after the "u8" and
+** "BusyHandler" typedefs. vdbe.h also requires a few of the opaque
+** pointer types (i.e. FuncDef) defined above.
+*/
+/************** Include os.h in the middle of sqliteInt.h ********************/
+/************** Begin file os.h **********************************************/
+/*
+** 2001 September 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file (together with is companion C source-code file
+** "os.c") attempt to abstract the underlying operating system so that
+** the SQLite library will work on both POSIX and windows systems.
+**
+** This header file is #include-ed by sqliteInt.h and thus ends up
+** being included by every source file.
+*/
+#ifndef _SQLITE_OS_H_
+#define _SQLITE_OS_H_
+
+/*
+** Attempt to automatically detect the operating system and setup the
+** necessary pre-processor macros for it.
+*/
+/************** Include os_setup.h in the middle of os.h *********************/
+/************** Begin file os_setup.h ****************************************/
+/*
+** 2013 November 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains pre-processor directives related to operating system
+** detection and/or setup.
+*/
+#ifndef SQLITE_OS_SETUP_H
+#define SQLITE_OS_SETUP_H
+
+/*
+** Figure out if we are dealing with Unix, Windows, or some other operating
+** system.
+**
+** After the following block of preprocess macros, all of
+**
+**    SQLITE_OS_KV
+**    SQLITE_OS_OTHER
+**    SQLITE_OS_UNIX
+**    SQLITE_OS_WIN
+**
+** will defined to either 1 or 0. One of them will be 1. The others will be 0.
+** If none of the macros are initially defined, then select either
+** SQLITE_OS_UNIX or SQLITE_OS_WIN depending on the target platform.
+**
+** If SQLITE_OS_OTHER=1 is specified at compile-time, then the application
+** must provide its own VFS implementation together with sqlite3_os_init()
+** and sqlite3_os_end() routines.
+*/
+#if !defined(SQLITE_OS_KV) && !defined(SQLITE_OS_OTHER) && \
+       !defined(SQLITE_OS_UNIX) && !defined(SQLITE_OS_WIN)
+#  if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || \
+          defined(__MINGW32__) || defined(__BORLANDC__)
+#    define SQLITE_OS_WIN 1
+#    define SQLITE_OS_UNIX 0
+#  else
+#    define SQLITE_OS_WIN 0
+#    define SQLITE_OS_UNIX 1
+#  endif
+#endif
+#if SQLITE_OS_OTHER+1>1
+#  undef SQLITE_OS_KV
+#  define SQLITE_OS_KV 0
+#  undef SQLITE_OS_UNIX
+#  define SQLITE_OS_UNIX 0
+#  undef SQLITE_OS_WIN
+#  define SQLITE_OS_WIN 0
+#endif
+#if SQLITE_OS_KV+1>1
+#  undef SQLITE_OS_OTHER
+#  define SQLITE_OS_OTHER 0
+#  undef SQLITE_OS_UNIX
+#  define SQLITE_OS_UNIX 0
+#  undef SQLITE_OS_WIN
+#  define SQLITE_OS_WIN 0
+#  define SQLITE_OMIT_LOAD_EXTENSION 1
+#  define SQLITE_OMIT_WAL 1
+#  define SQLITE_OMIT_DEPRECATED 1
+#  undef SQLITE_TEMP_STORE
+#  define SQLITE_TEMP_STORE 3  /* Always use memory for temporary storage */
+#  define SQLITE_DQS 0
+#  define SQLITE_OMIT_SHARED_CACHE 1
+#  define SQLITE_OMIT_AUTOINIT 1
+#endif
+#if SQLITE_OS_UNIX+1>1
+#  undef SQLITE_OS_KV
+#  define SQLITE_OS_KV 0
+#  undef SQLITE_OS_OTHER
+#  define SQLITE_OS_OTHER 0
+#  undef SQLITE_OS_WIN
+#  define SQLITE_OS_WIN 0
+#endif
+#if SQLITE_OS_WIN+1>1
+#  undef SQLITE_OS_KV
+#  define SQLITE_OS_KV 0
+#  undef SQLITE_OS_OTHER
+#  define SQLITE_OS_OTHER 0
+#  undef SQLITE_OS_UNIX
+#  define SQLITE_OS_UNIX 0
+#endif
+
+
+#endif /* SQLITE_OS_SETUP_H */
+
+/************** End of os_setup.h ********************************************/
+/************** Continuing where we left off in os.h *************************/
+
+/* If the SET_FULLSYNC macro is not defined above, then make it
+** a no-op
+*/
+#ifndef SET_FULLSYNC
+# define SET_FULLSYNC(x,y)
+#endif
+
+/* Maximum pathname length.  Note: FILENAME_MAX defined by stdio.h
+*/
+#ifndef SQLITE_MAX_PATHLEN
+# define SQLITE_MAX_PATHLEN FILENAME_MAX
+#endif
+
+/* Maximum number of symlinks that will be resolved while trying to
+** expand a filename in xFullPathname() in the VFS.
+*/
+#ifndef SQLITE_MAX_SYMLINK
+# define SQLITE_MAX_SYMLINK 200
+#endif
+
+/*
+** The default size of a disk sector
+*/
+#ifndef SQLITE_DEFAULT_SECTOR_SIZE
+# define SQLITE_DEFAULT_SECTOR_SIZE 4096
+#endif
+
+/*
+** Temporary files are named starting with this prefix followed by 16 random
+** alphanumeric characters, and no file extension. They are stored in the
+** OS's standard temporary file directory, and are deleted prior to exit.
+** If sqlite is being embedded in another program, you may wish to change the
+** prefix to reflect your program's name, so that if your program exits
+** prematurely, old temporary files can be easily identified. This can be done
+** using -DSQLITE_TEMP_FILE_PREFIX=myprefix_ on the compiler command line.
+**
+** 2006-10-31:  The default prefix used to be "sqlite_".  But then
+** Mcafee started using SQLite in their anti-virus product and it
+** started putting files with the "sqlite" name in the c:/temp folder.
+** This annoyed many windows users.  Those users would then do a
+** Google search for "sqlite", find the telephone numbers of the
+** developers and call to wake them up at night and complain.
+** For this reason, the default name prefix is changed to be "sqlite"
+** spelled backwards.  So the temp files are still identified, but
+** anybody smart enough to figure out the code is also likely smart
+** enough to know that calling the developer will not help get rid
+** of the file.
+*/
+#ifndef SQLITE_TEMP_FILE_PREFIX
+# define SQLITE_TEMP_FILE_PREFIX "etilqs_"
+#endif
+
+/*
+** The following values may be passed as the second argument to
+** sqlite3OsLock(). The various locks exhibit the following semantics:
+**
+** SHARED:    Any number of processes may hold a SHARED lock simultaneously.
+** RESERVED:  A single process may hold a RESERVED lock on a file at
+**            any time. Other processes may hold and obtain new SHARED locks.
+** PENDING:   A single process may hold a PENDING lock on a file at
+**            any one time. Existing SHARED locks may persist, but no new
+**            SHARED locks may be obtained by other processes.
+** EXCLUSIVE: An EXCLUSIVE lock precludes all other locks.
+**
+** PENDING_LOCK may not be passed directly to sqlite3OsLock(). Instead, a
+** process that requests an EXCLUSIVE lock may actually obtain a PENDING
+** lock. This can be upgraded to an EXCLUSIVE lock by a subsequent call to
+** sqlite3OsLock().
+*/
+#define NO_LOCK         0
+#define SHARED_LOCK     1
+#define RESERVED_LOCK   2
+#define PENDING_LOCK    3
+#define EXCLUSIVE_LOCK  4
+
+/*
+** File Locking Notes:  (Mostly about windows but also some info for Unix)
+**
+** We cannot use LockFileEx() or UnlockFileEx() on Win95/98/ME because
+** those functions are not available.  So we use only LockFile() and
+** UnlockFile().
+**
+** LockFile() prevents not just writing but also reading by other processes.
+** A SHARED_LOCK is obtained by locking a single randomly-chosen
+** byte out of a specific range of bytes. The lock byte is obtained at
+** random so two separate readers can probably access the file at the
+** same time, unless they are unlucky and choose the same lock byte.
+** An EXCLUSIVE_LOCK is obtained by locking all bytes in the range.
+** There can only be one writer.  A RESERVED_LOCK is obtained by locking
+** a single byte of the file that is designated as the reserved lock byte.
+** A PENDING_LOCK is obtained by locking a designated byte different from
+** the RESERVED_LOCK byte.
+**
+** On WinNT/2K/XP systems, LockFileEx() and UnlockFileEx() are available,
+** which means we can use reader/writer locks.  When reader/writer locks
+** are used, the lock is placed on the same range of bytes that is used
+** for probabilistic locking in Win95/98/ME.  Hence, the locking scheme
+** will support two or more Win95 readers or two or more WinNT readers.
+** But a single Win95 reader will lock out all WinNT readers and a single
+** WinNT reader will lock out all other Win95 readers.
+**
+** The following #defines specify the range of bytes used for locking.
+** SHARED_SIZE is the number of bytes available in the pool from which
+** a random byte is selected for a shared lock.  The pool of bytes for
+** shared locks begins at SHARED_FIRST.
+**
+** The same locking strategy and
+** byte ranges are used for Unix.  This leaves open the possibility of having
+** clients on win95, winNT, and unix all talking to the same shared file
+** and all locking correctly.  To do so would require that samba (or whatever
+** tool is being used for file sharing) implements locks correctly between
+** windows and unix.  I'm guessing that isn't likely to happen, but by
+** using the same locking range we are at least open to the possibility.
+**
+** Locking in windows is manditory.  For this reason, we cannot store
+** actual data in the bytes used for locking.  The pager never allocates
+** the pages involved in locking therefore.  SHARED_SIZE is selected so
+** that all locks will fit on a single page even at the minimum page size.
+** PENDING_BYTE defines the beginning of the locks.  By default PENDING_BYTE
+** is set high so that we don't have to allocate an unused page except
+** for very large databases.  But one should test the page skipping logic
+** by setting PENDING_BYTE low and running the entire regression suite.
+**
+** Changing the value of PENDING_BYTE results in a subtly incompatible
+** file format.  Depending on how it is changed, you might not notice
+** the incompatibility right away, even running a full regression test.
+** The default location of PENDING_BYTE is the first byte past the
+** 1GB boundary.
+**
+*/
+#ifdef SQLITE_OMIT_WSD
+# define PENDING_BYTE     (0x40000000)
+#else
+# define PENDING_BYTE      sqlite3PendingByte
+#endif
+#define RESERVED_BYTE     (PENDING_BYTE+1)
+#define SHARED_FIRST      (PENDING_BYTE+2)
+#define SHARED_SIZE       510
+
+/*
+** Wrapper around OS specific sqlite3_os_init() function.
+*/
+SQLITE_PRIVATE int sqlite3OsInit(void);
+
+/*
+** Functions for accessing sqlite3_file methods
+*/
+SQLITE_PRIVATE void sqlite3OsClose(sqlite3_file*);
+SQLITE_PRIVATE int sqlite3OsRead(sqlite3_file*, void*, int amt, i64 offset);
+SQLITE_PRIVATE int sqlite3OsWrite(sqlite3_file*, const void*, int amt, i64 offset);
+SQLITE_PRIVATE int sqlite3OsTruncate(sqlite3_file*, i64 size);
+SQLITE_PRIVATE int sqlite3OsSync(sqlite3_file*, int);
+SQLITE_PRIVATE int sqlite3OsFileSize(sqlite3_file*, i64 *pSize);
+SQLITE_PRIVATE int sqlite3OsLock(sqlite3_file*, int);
+SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file*, int);
+SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut);
+SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file*,int,void*);
+SQLITE_PRIVATE void sqlite3OsFileControlHint(sqlite3_file*,int,void*);
+#define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0
+SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id);
+SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id);
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE int sqlite3OsShmMap(sqlite3_file *,int,int,int,void volatile **);
+SQLITE_PRIVATE int sqlite3OsShmLock(sqlite3_file *id, int, int, int);
+SQLITE_PRIVATE void sqlite3OsShmBarrier(sqlite3_file *id);
+SQLITE_PRIVATE int sqlite3OsShmUnmap(sqlite3_file *id, int);
+#endif /* SQLITE_OMIT_WAL */
+SQLITE_PRIVATE int sqlite3OsFetch(sqlite3_file *id, i64, int, void **);
+SQLITE_PRIVATE int sqlite3OsUnfetch(sqlite3_file *, i64, void *);
+
+
+/*
+** Functions for accessing sqlite3_vfs methods
+*/
+SQLITE_PRIVATE int sqlite3OsOpen(sqlite3_vfs *, const char *, sqlite3_file*, int, int *);
+SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *, const char *, int);
+SQLITE_PRIVATE int sqlite3OsAccess(sqlite3_vfs *, const char *, int, int *pResOut);
+SQLITE_PRIVATE int sqlite3OsFullPathname(sqlite3_vfs *, const char *, int, char *);
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *, const char *);
+SQLITE_PRIVATE void sqlite3OsDlError(sqlite3_vfs *, int, char *);
+SQLITE_PRIVATE void (*sqlite3OsDlSym(sqlite3_vfs *, void *, const char *))(void);
+SQLITE_PRIVATE void sqlite3OsDlClose(sqlite3_vfs *, void *);
+#endif /* SQLITE_OMIT_LOAD_EXTENSION */
+SQLITE_PRIVATE int sqlite3OsRandomness(sqlite3_vfs *, int, char *);
+SQLITE_PRIVATE int sqlite3OsSleep(sqlite3_vfs *, int);
+SQLITE_PRIVATE int sqlite3OsGetLastError(sqlite3_vfs*);
+SQLITE_PRIVATE int sqlite3OsCurrentTimeInt64(sqlite3_vfs *, sqlite3_int64*);
+
+/*
+** Convenience functions for opening and closing files using
+** sqlite3_malloc() to obtain space for the file-handle structure.
+*/
+SQLITE_PRIVATE int sqlite3OsOpenMalloc(sqlite3_vfs *, const char *, sqlite3_file **, int,int*);
+SQLITE_PRIVATE void sqlite3OsCloseFree(sqlite3_file *);
+
+#endif /* _SQLITE_OS_H_ */
+
+/************** End of os.h **************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include pager.h in the middle of sqliteInt.h *****************/
+/************** Begin file pager.h *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite page cache
+** subsystem.  The page cache subsystem reads and writes a file a page
+** at a time and provides a journal for rollback.
+*/
+
+#ifndef SQLITE_PAGER_H
+#define SQLITE_PAGER_H
+
+/*
+** Default maximum size for persistent journal files. A negative
+** value means no limit. This value may be overridden using the
+** sqlite3PagerJournalSizeLimit() API. See also "PRAGMA journal_size_limit".
+*/
+#ifndef SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT
+  #define SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT -1
+#endif
+
+/*
+** The type used to represent a page number.  The first page in a file
+** is called page 1.  0 is used to represent "not a page".
+*/
+typedef u32 Pgno;
+
+/*
+** Each open file is managed by a separate instance of the "Pager" structure.
+*/
+typedef struct Pager Pager;
+
+/*
+** Handle type for pages.
+*/
+typedef struct PgHdr DbPage;
+
+/*
+** Page number PAGER_SJ_PGNO is never used in an SQLite database (it is
+** reserved for working around a windows/posix incompatibility). It is
+** used in the journal to signify that the remainder of the journal file
+** is devoted to storing a super-journal name - there are no more pages to
+** roll back. See comments for function writeSuperJournal() in pager.c
+** for details.
+*/
+#define PAGER_SJ_PGNO_COMPUTED(x) ((Pgno)((PENDING_BYTE/((x)->pageSize))+1))
+#define PAGER_SJ_PGNO(x)          ((x)->lckPgno)
+
+/*
+** Allowed values for the flags parameter to sqlite3PagerOpen().
+**
+** NOTE: These values must match the corresponding BTREE_ values in btree.h.
+*/
+#define PAGER_OMIT_JOURNAL  0x0001    /* Do not use a rollback journal */
+#define PAGER_MEMORY        0x0002    /* In-memory database */
+
+/*
+** Valid values for the second argument to sqlite3PagerLockingMode().
+*/
+#define PAGER_LOCKINGMODE_QUERY      -1
+#define PAGER_LOCKINGMODE_NORMAL      0
+#define PAGER_LOCKINGMODE_EXCLUSIVE   1
+
+/*
+** Numeric constants that encode the journalmode.
+**
+** The numeric values encoded here (other than PAGER_JOURNALMODE_QUERY)
+** are exposed in the API via the "PRAGMA journal_mode" command and
+** therefore cannot be changed without a compatibility break.
+*/
+#define PAGER_JOURNALMODE_QUERY     (-1)  /* Query the value of journalmode */
+#define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */
+#define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */
+#define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */
+#define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */
+#define PAGER_JOURNALMODE_MEMORY      4   /* In-memory journal file */
+#define PAGER_JOURNALMODE_WAL         5   /* Use write-ahead logging */
+
+#define isWalMode(x) ((x)==PAGER_JOURNALMODE_WAL)
+
+/*
+** The argument to this macro is a file descriptor (type sqlite3_file*).
+** Return 0 if it is not open, or non-zero (but not 1) if it is.
+**
+** This is so that expressions can be written as:
+**
+**   if( isOpen(pPager->jfd) ){ ...
+**
+** instead of
+**
+**   if( pPager->jfd->pMethods ){ ...
+*/
+#define isOpen(pFd) ((pFd)->pMethods!=0)
+
+/*
+** Flags that make up the mask passed to sqlite3PagerGet().
+*/
+#define PAGER_GET_NOCONTENT     0x01  /* Do not load data from disk */
+#define PAGER_GET_READONLY      0x02  /* Read-only page is acceptable */
+
+/*
+** Flags for sqlite3PagerSetFlags()
+**
+** Value constraints (enforced via assert()):
+**    PAGER_FULLFSYNC      == SQLITE_FullFSync
+**    PAGER_CKPT_FULLFSYNC == SQLITE_CkptFullFSync
+**    PAGER_CACHE_SPILL    == SQLITE_CacheSpill
+*/
+#define PAGER_SYNCHRONOUS_OFF       0x01  /* PRAGMA synchronous=OFF */
+#define PAGER_SYNCHRONOUS_NORMAL    0x02  /* PRAGMA synchronous=NORMAL */
+#define PAGER_SYNCHRONOUS_FULL      0x03  /* PRAGMA synchronous=FULL */
+#define PAGER_SYNCHRONOUS_EXTRA     0x04  /* PRAGMA synchronous=EXTRA */
+#define PAGER_SYNCHRONOUS_MASK      0x07  /* Mask for four values above */
+#define PAGER_FULLFSYNC             0x08  /* PRAGMA fullfsync=ON */
+#define PAGER_CKPT_FULLFSYNC        0x10  /* PRAGMA checkpoint_fullfsync=ON */
+#define PAGER_CACHESPILL            0x20  /* PRAGMA cache_spill=ON */
+#define PAGER_FLAGS_MASK            0x38  /* All above except SYNCHRONOUS */
+
+/*
+** The remainder of this file contains the declarations of the functions
+** that make up the Pager sub-system API. See source code comments for
+** a detailed description of each routine.
+*/
+
+/* Open and close a Pager connection. */
+SQLITE_PRIVATE int sqlite3PagerOpen(
+  sqlite3_vfs*,
+  Pager **ppPager,
+  const char*,
+  int,
+  int,
+  int,
+  void(*)(DbPage*)
+);
+SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager, sqlite3*);
+SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
+
+/* Functions used to configure a Pager object. */
+SQLITE_PRIVATE void sqlite3PagerSetBusyHandler(Pager*, int(*)(void *), void *);
+SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager*, u32*, int);
+SQLITE_PRIVATE Pgno sqlite3PagerMaxPageCount(Pager*, Pgno);
+SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager*, int);
+SQLITE_PRIVATE int sqlite3PagerSetSpillsize(Pager*, int);
+SQLITE_PRIVATE void sqlite3PagerSetMmapLimit(Pager *, sqlite3_int64);
+SQLITE_PRIVATE void sqlite3PagerShrink(Pager*);
+SQLITE_PRIVATE void sqlite3PagerSetFlags(Pager*,unsigned);
+SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *, int);
+SQLITE_PRIVATE int sqlite3PagerSetJournalMode(Pager *, int);
+SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager*);
+SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager*);
+SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
+SQLITE_PRIVATE sqlite3_backup **sqlite3PagerBackupPtr(Pager*);
+SQLITE_PRIVATE int sqlite3PagerFlush(Pager*);
+
+/* Functions used to obtain and release page references. */
+SQLITE_PRIVATE int sqlite3PagerGet(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag);
+SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno);
+SQLITE_PRIVATE void sqlite3PagerRef(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerUnref(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerUnrefNotNull(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerUnrefPageOne(DbPage*);
+
+/* Operations on page references. */
+SQLITE_PRIVATE int sqlite3PagerWrite(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerDontWrite(DbPage*);
+SQLITE_PRIVATE int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int);
+SQLITE_PRIVATE int sqlite3PagerPageRefcount(DbPage*);
+SQLITE_PRIVATE void *sqlite3PagerGetData(DbPage *);
+SQLITE_PRIVATE void *sqlite3PagerGetExtra(DbPage *);
+
+/* Functions used to manage pager transactions and savepoints. */
+SQLITE_PRIVATE void sqlite3PagerPagecount(Pager*, int*);
+SQLITE_PRIVATE int sqlite3PagerBegin(Pager*, int exFlag, int);
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(Pager*,const char *zSuper, int);
+SQLITE_PRIVATE int sqlite3PagerExclusiveLock(Pager*);
+SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager, const char *zSuper);
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager*);
+SQLITE_PRIVATE int sqlite3PagerRollback(Pager*);
+SQLITE_PRIVATE int sqlite3PagerOpenSavepoint(Pager *pPager, int n);
+SQLITE_PRIVATE int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);
+SQLITE_PRIVATE int sqlite3PagerSharedLock(Pager *pPager);
+
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE   int sqlite3PagerCheckpoint(Pager *pPager, sqlite3*, int, int*, int*);
+SQLITE_PRIVATE   int sqlite3PagerWalSupported(Pager *pPager);
+SQLITE_PRIVATE   int sqlite3PagerWalCallback(Pager *pPager);
+SQLITE_PRIVATE   int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
+SQLITE_PRIVATE   int sqlite3PagerCloseWal(Pager *pPager, sqlite3*);
+# ifdef SQLITE_ENABLE_SNAPSHOT
+SQLITE_PRIVATE   int sqlite3PagerSnapshotGet(Pager*, sqlite3_snapshot **ppSnapshot);
+SQLITE_PRIVATE   int sqlite3PagerSnapshotOpen(Pager*, sqlite3_snapshot *pSnapshot);
+SQLITE_PRIVATE   int sqlite3PagerSnapshotRecover(Pager *pPager);
+SQLITE_PRIVATE   int sqlite3PagerSnapshotCheck(Pager *pPager, sqlite3_snapshot *pSnapshot);
+SQLITE_PRIVATE   void sqlite3PagerSnapshotUnlock(Pager *pPager);
+# endif
+#endif
+
+#if !defined(SQLITE_OMIT_WAL) && defined(SQLITE_ENABLE_SETLK_TIMEOUT)
+SQLITE_PRIVATE   int sqlite3PagerWalWriteLock(Pager*, int);
+SQLITE_PRIVATE   void sqlite3PagerWalDb(Pager*, sqlite3*);
+#else
+# define sqlite3PagerWalWriteLock(y,z) SQLITE_OK
+# define sqlite3PagerWalDb(x,y)
+#endif
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+SQLITE_PRIVATE   int sqlite3PagerDirectReadOk(Pager *pPager, Pgno pgno);
+#endif
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+SQLITE_PRIVATE   int sqlite3PagerWalFramesize(Pager *pPager);
+#endif
+
+/* Functions used to query pager state and configuration. */
+SQLITE_PRIVATE u8 sqlite3PagerIsreadonly(Pager*);
+SQLITE_PRIVATE u32 sqlite3PagerDataVersion(Pager*);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   int sqlite3PagerRefcount(Pager*);
+#endif
+SQLITE_PRIVATE int sqlite3PagerMemUsed(Pager*);
+SQLITE_PRIVATE const char *sqlite3PagerFilename(const Pager*, int);
+SQLITE_PRIVATE sqlite3_vfs *sqlite3PagerVfs(Pager*);
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerFile(Pager*);
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerJrnlFile(Pager*);
+SQLITE_PRIVATE const char *sqlite3PagerJournalname(Pager*);
+SQLITE_PRIVATE void *sqlite3PagerTempSpace(Pager*);
+SQLITE_PRIVATE int sqlite3PagerIsMemdb(Pager*);
+SQLITE_PRIVATE void sqlite3PagerCacheStat(Pager *, int, int, u64*);
+SQLITE_PRIVATE void sqlite3PagerClearCache(Pager*);
+SQLITE_PRIVATE int sqlite3SectorSize(sqlite3_file *);
+
+/* Functions used to truncate the database file. */
+SQLITE_PRIVATE void sqlite3PagerTruncateImage(Pager*,Pgno);
+
+SQLITE_PRIVATE void sqlite3PagerRekey(DbPage*, Pgno, u16);
+
+/* Functions to support testing and debugging. */
+#if !defined(NDEBUG) || defined(SQLITE_TEST)
+SQLITE_PRIVATE   Pgno sqlite3PagerPagenumber(DbPage*);
+SQLITE_PRIVATE   int sqlite3PagerIswriteable(DbPage*);
+#endif
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE   int *sqlite3PagerStats(Pager*);
+SQLITE_PRIVATE   void sqlite3PagerRefdump(Pager*);
+  void disable_simulated_io_errors(void);
+  void enable_simulated_io_errors(void);
+#else
+# define disable_simulated_io_errors()
+# define enable_simulated_io_errors()
+#endif
+
+#if defined(SQLITE_USE_SEH) && !defined(SQLITE_OMIT_WAL)
+SQLITE_PRIVATE int sqlite3PagerWalSystemErrno(Pager*);
+#endif
+
+#endif /* SQLITE_PAGER_H */
+
+/************** End of pager.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include btree.h in the middle of sqliteInt.h *****************/
+/************** Begin file btree.h *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite B-Tree file
+** subsystem.  See comments in the source code for a detailed description
+** of what each interface routine does.
+*/
+#ifndef SQLITE_BTREE_H
+#define SQLITE_BTREE_H
+
+/* TODO: This definition is just included so other modules compile. It
+** needs to be revisited.
+*/
+#define SQLITE_N_BTREE_META 16
+
+/*
+** If defined as non-zero, auto-vacuum is enabled by default. Otherwise
+** it must be turned on for each database using "PRAGMA auto_vacuum = 1".
+*/
+#ifndef SQLITE_DEFAULT_AUTOVACUUM
+  #define SQLITE_DEFAULT_AUTOVACUUM 0
+#endif
+
+#define BTREE_AUTOVACUUM_NONE 0        /* Do not do auto-vacuum */
+#define BTREE_AUTOVACUUM_FULL 1        /* Do full auto-vacuum */
+#define BTREE_AUTOVACUUM_INCR 2        /* Incremental vacuum */
+
+/*
+** Forward declarations of structure
+*/
+typedef struct Btree Btree;
+typedef struct BtCursor BtCursor;
+typedef struct BtShared BtShared;
+typedef struct BtreePayload BtreePayload;
+
+
+SQLITE_PRIVATE int sqlite3BtreeOpen(
+  sqlite3_vfs *pVfs,       /* VFS to use with this b-tree */
+  const char *zFilename,   /* Name of database file to open */
+  sqlite3 *db,             /* Associated database connection */
+  Btree **ppBtree,         /* Return open Btree* here */
+  int flags,               /* Flags */
+  int vfsFlags             /* Flags passed through to VFS open */
+);
+
+/* The flags parameter to sqlite3BtreeOpen can be the bitwise or of the
+** following values.
+**
+** NOTE:  These values must match the corresponding PAGER_ values in
+** pager.h.
+*/
+#define BTREE_OMIT_JOURNAL  1  /* Do not create or use a rollback journal */
+#define BTREE_MEMORY        2  /* This is an in-memory DB */
+#define BTREE_SINGLE        4  /* The file contains at most 1 b-tree */
+#define BTREE_UNORDERED     8  /* Use of a hash implementation is OK */
+
+SQLITE_PRIVATE int sqlite3BtreeClose(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeSetSpillSize(Btree*,int);
+#if SQLITE_MAX_MMAP_SIZE>0
+SQLITE_PRIVATE   int sqlite3BtreeSetMmapLimit(Btree*,sqlite3_int64);
+#endif
+SQLITE_PRIVATE int sqlite3BtreeSetPagerFlags(Btree*,unsigned);
+SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int nPagesize, int nReserve, int eFix);
+SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree*);
+SQLITE_PRIVATE Pgno sqlite3BtreeMaxPageCount(Btree*,Pgno);
+SQLITE_PRIVATE Pgno sqlite3BtreeLastPage(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeSecureDelete(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeGetRequestedReserve(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeGetReserveNoMutex(Btree *p);
+SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *, int);
+SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *);
+SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree*,int,int*);
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree*, const char*);
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree*, int);
+SQLITE_PRIVATE int sqlite3BtreeCommit(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeRollback(Btree*,int,int);
+SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree*, Pgno*, int flags);
+SQLITE_PRIVATE int sqlite3BtreeTxnState(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeIsInBackup(Btree*);
+
+SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *, int, void(*)(void *));
+SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *pBtree);
+#ifndef SQLITE_OMIT_SHARED_CACHE
+SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *pBtree, int iTab, u8 isWriteLock);
+#endif
+
+/* Savepoints are named, nestable SQL transactions mostly implemented */
+/* in vdbe.c and pager.c See https://sqlite.org/lang_savepoint.html */
+SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *, int, int);
+
+/* "Checkpoint" only refers to WAL. See https://sqlite.org/wal.html#ckpt */
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE   int sqlite3BtreeCheckpoint(Btree*, int, int *, int *);
+#endif
+
+SQLITE_PRIVATE const char *sqlite3BtreeGetFilename(Btree *);
+SQLITE_PRIVATE const char *sqlite3BtreeGetJournalname(Btree *);
+SQLITE_PRIVATE int sqlite3BtreeCopyFile(Btree *, Btree *);
+
+SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *);
+
+/* The flags parameter to sqlite3BtreeCreateTable can be the bitwise OR
+** of the flags shown below.
+**
+** Every SQLite table must have either BTREE_INTKEY or BTREE_BLOBKEY set.
+** With BTREE_INTKEY, the table key is a 64-bit integer and arbitrary data
+** is stored in the leaves.  (BTREE_INTKEY is used for SQL tables.)  With
+** BTREE_BLOBKEY, the key is an arbitrary BLOB and no content is stored
+** anywhere - the key is the content.  (BTREE_BLOBKEY is used for SQL
+** indices.)
+*/
+#define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
+#define BTREE_BLOBKEY    2    /* Table has keys only - no data */
+
+SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree*, int, int*);
+SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree*, int, i64*);
+SQLITE_PRIVATE int sqlite3BtreeClearTableOfCursor(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreeTripAllCursors(Btree*, int, int);
+
+SQLITE_PRIVATE void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue);
+SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);
+
+SQLITE_PRIVATE int sqlite3BtreeNewDb(Btree *p);
+
+/*
+** The second parameter to sqlite3BtreeGetMeta or sqlite3BtreeUpdateMeta
+** should be one of the following values. The integer values are assigned
+** to constants so that the offset of the corresponding field in an
+** SQLite database header may be found using the following formula:
+**
+**   offset = 36 + (idx * 4)
+**
+** For example, the free-page-count field is located at byte offset 36 of
+** the database file header. The incr-vacuum-flag field is located at
+** byte offset 64 (== 36+4*7).
+**
+** The BTREE_DATA_VERSION value is not really a value stored in the header.
+** It is a read-only number computed by the pager.  But we merge it with
+** the header value access routines since its access pattern is the same.
+** Call it a "virtual meta value".
+*/
+#define BTREE_FREE_PAGE_COUNT     0
+#define BTREE_SCHEMA_VERSION      1
+#define BTREE_FILE_FORMAT         2
+#define BTREE_DEFAULT_CACHE_SIZE  3
+#define BTREE_LARGEST_ROOT_PAGE   4
+#define BTREE_TEXT_ENCODING       5
+#define BTREE_USER_VERSION        6
+#define BTREE_INCR_VACUUM         7
+#define BTREE_APPLICATION_ID      8
+#define BTREE_DATA_VERSION        15  /* A virtual meta-value */
+
+/*
+** Kinds of hints that can be passed into the sqlite3BtreeCursorHint()
+** interface.
+**
+** BTREE_HINT_RANGE  (arguments: Expr*, Mem*)
+**
+**     The first argument is an Expr* (which is guaranteed to be constant for
+**     the lifetime of the cursor) that defines constraints on which rows
+**     might be fetched with this cursor.  The Expr* tree may contain
+**     TK_REGISTER nodes that refer to values stored in the array of registers
+**     passed as the second parameter.  In other words, if Expr.op==TK_REGISTER
+**     then the value of the node is the value in Mem[pExpr.iTable].  Any
+**     TK_COLUMN node in the expression tree refers to the Expr.iColumn-th
+**     column of the b-tree of the cursor.  The Expr tree will not contain
+**     any function calls nor subqueries nor references to b-trees other than
+**     the cursor being hinted.
+**
+**     The design of the _RANGE hint is aid b-tree implementations that try
+**     to prefetch content from remote machines - to provide those
+**     implementations with limits on what needs to be prefetched and thereby
+**     reduce network bandwidth.
+**
+** Note that BTREE_HINT_FLAGS with BTREE_BULKLOAD is the only hint used by
+** standard SQLite.  The other hints are provided for extensions that use
+** the SQLite parser and code generator but substitute their own storage
+** engine.
+*/
+#define BTREE_HINT_RANGE 0       /* Range constraints on queries */
+
+/*
+** Values that may be OR'd together to form the argument to the
+** BTREE_HINT_FLAGS hint for sqlite3BtreeCursorHint():
+**
+** The BTREE_BULKLOAD flag is set on index cursors when the index is going
+** to be filled with content that is already in sorted order.
+**
+** The BTREE_SEEK_EQ flag is set on cursors that will get OP_SeekGE or
+** OP_SeekLE opcodes for a range search, but where the range of entries
+** selected will all have the same key.  In other words, the cursor will
+** be used only for equality key searches.
+**
+*/
+#define BTREE_BULKLOAD 0x00000001  /* Used to full index in sorted order */
+#define BTREE_SEEK_EQ  0x00000002  /* EQ seeks only - no range seeks */
+
+/*
+** Flags passed as the third argument to sqlite3BtreeCursor().
+**
+** For read-only cursors the wrFlag argument is always zero. For read-write
+** cursors it may be set to either (BTREE_WRCSR|BTREE_FORDELETE) or just
+** (BTREE_WRCSR). If the BTREE_FORDELETE bit is set, then the cursor will
+** only be used by SQLite for the following:
+**
+**   * to seek to and then delete specific entries, and/or
+**
+**   * to read values that will be used to create keys that other
+**     BTREE_FORDELETE cursors will seek to and delete.
+**
+** The BTREE_FORDELETE flag is an optimization hint.  It is not used by
+** by this, the native b-tree engine of SQLite, but it is available to
+** alternative storage engines that might be substituted in place of this
+** b-tree system.  For alternative storage engines in which a delete of
+** the main table row automatically deletes corresponding index rows,
+** the FORDELETE flag hint allows those alternative storage engines to
+** skip a lot of work.  Namely:  FORDELETE cursors may treat all SEEK
+** and DELETE operations as no-ops, and any READ operation against a
+** FORDELETE cursor may return a null row: 0x01 0x00.
+*/
+#define BTREE_WRCSR     0x00000004     /* read-write cursor */
+#define BTREE_FORDELETE 0x00000008     /* Cursor is for seek/delete only */
+
+SQLITE_PRIVATE int sqlite3BtreeCursor(
+  Btree*,                              /* BTree containing table to open */
+  Pgno iTable,                         /* Index of root page */
+  int wrFlag,                          /* 1 for writing.  0 for read-only */
+  struct KeyInfo*,                     /* First argument to compare function */
+  BtCursor *pCursor                    /* Space to write cursor structure */
+);
+SQLITE_PRIVATE BtCursor *sqlite3BtreeFakeValidCursor(void);
+SQLITE_PRIVATE int sqlite3BtreeCursorSize(void);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3BtreeClosesWithCursor(Btree*,BtCursor*);
+#endif
+SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor*);
+SQLITE_PRIVATE void sqlite3BtreeCursorHintFlags(BtCursor*, unsigned);
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+SQLITE_PRIVATE void sqlite3BtreeCursorHint(BtCursor*, int, ...);
+#endif
+
+SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreeTableMoveto(
+  BtCursor*,
+  i64 intKey,
+  int bias,
+  int *pRes
+);
+SQLITE_PRIVATE int sqlite3BtreeIndexMoveto(
+  BtCursor*,
+  UnpackedRecord *pUnKey,
+  int *pRes
+);
+SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreeCursorRestore(BtCursor*, int*);
+SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor*, u8 flags);
+
+/* Allowed flags for sqlite3BtreeDelete() and sqlite3BtreeInsert() */
+#define BTREE_SAVEPOSITION 0x02  /* Leave cursor pointing at NEXT or PREV */
+#define BTREE_AUXDELETE    0x04  /* not the primary delete operation */
+#define BTREE_APPEND       0x08  /* Insert is likely an append */
+#define BTREE_PREFORMAT    0x80  /* Inserted data is a preformated cell */
+
+/* An instance of the BtreePayload object describes the content of a single
+** entry in either an index or table btree.
+**
+** Index btrees (used for indexes and also WITHOUT ROWID tables) contain
+** an arbitrary key and no data.  These btrees have pKey,nKey set to the
+** key and the pData,nData,nZero fields are uninitialized.  The aMem,nMem
+** fields give an array of Mem objects that are a decomposition of the key.
+** The nMem field might be zero, indicating that no decomposition is available.
+**
+** Table btrees (used for rowid tables) contain an integer rowid used as
+** the key and passed in the nKey field.  The pKey field is zero.
+** pData,nData hold the content of the new entry.  nZero extra zero bytes
+** are appended to the end of the content when constructing the entry.
+** The aMem,nMem fields are uninitialized for table btrees.
+**
+** Field usage summary:
+**
+**               Table BTrees                   Index Btrees
+**
+**   pKey        always NULL                    encoded key
+**   nKey        the ROWID                      length of pKey
+**   pData       data                           not used
+**   aMem        not used                       decomposed key value
+**   nMem        not used                       entries in aMem
+**   nData       length of pData                not used
+**   nZero       extra zeros after pData        not used
+**
+** This object is used to pass information into sqlite3BtreeInsert().  The
+** same information used to be passed as five separate parameters.  But placing
+** the information into this object helps to keep the interface more
+** organized and understandable, and it also helps the resulting code to
+** run a little faster by using fewer registers for parameter passing.
+*/
+struct BtreePayload {
+  const void *pKey;       /* Key content for indexes.  NULL for tables */
+  sqlite3_int64 nKey;     /* Size of pKey for indexes.  PRIMARY KEY for tabs */
+  const void *pData;      /* Data for tables. */
+  sqlite3_value *aMem;    /* First of nMem value in the unpacked pKey */
+  u16 nMem;               /* Number of aMem[] value.  Might be zero */
+  int nData;              /* Size of pData.  0 if none. */
+  int nZero;              /* Extra zero data appended after pData,nData */
+};
+
+SQLITE_PRIVATE int sqlite3BtreeInsert(BtCursor*, const BtreePayload *pPayload,
+                       int flags, int seekResult);
+SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor*, int *pRes);
+SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor*, int *pRes);
+SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor*, int flags);
+SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor*, int flags);
+SQLITE_PRIVATE i64 sqlite3BtreeIntegerKey(BtCursor*);
+SQLITE_PRIVATE void sqlite3BtreeCursorPin(BtCursor*);
+SQLITE_PRIVATE void sqlite3BtreeCursorUnpin(BtCursor*);
+SQLITE_PRIVATE i64 sqlite3BtreeOffset(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*);
+SQLITE_PRIVATE const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt);
+SQLITE_PRIVATE u32 sqlite3BtreePayloadSize(BtCursor*);
+SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor*);
+
+SQLITE_PRIVATE int sqlite3BtreeIntegrityCheck(
+  sqlite3 *db,  /* Database connection that is running the check */
+  Btree *p,     /* The btree to be checked */
+  Pgno *aRoot,  /* An array of root pages numbers for individual trees */
+  sqlite3_value *aCnt,  /* OUT: entry counts for each btree in aRoot[] */
+  int nRoot,    /* Number of entries in aRoot[] */
+  int mxErr,    /* Stop reporting errors after this many */
+  int *pnErr,   /* OUT: Write number of errors seen to this variable */
+  char **pzOut  /* OUT: Write the error message string here */
+);
+SQLITE_PRIVATE struct Pager *sqlite3BtreePager(Btree*);
+SQLITE_PRIVATE i64 sqlite3BtreeRowCountEst(BtCursor*);
+
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE int sqlite3BtreePayloadChecked(BtCursor*, u32 offset, u32 amt, void*);
+SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*);
+SQLITE_PRIVATE void sqlite3BtreeIncrblobCursor(BtCursor *);
+#endif
+SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *);
+SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBt, int iVersion);
+SQLITE_PRIVATE int sqlite3BtreeCursorHasHint(BtCursor*, unsigned int mask);
+SQLITE_PRIVATE int sqlite3BtreeIsReadonly(Btree *pBt);
+SQLITE_PRIVATE int sqlite3HeaderSizeBtree(void);
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE sqlite3_uint64 sqlite3BtreeSeekCount(Btree*);
+#else
+# define sqlite3BtreeSeekCount(X) 0
+#endif
+
+#ifndef NDEBUG
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValid(BtCursor*);
+#endif
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValidNN(BtCursor*);
+
+SQLITE_PRIVATE int sqlite3BtreeCount(sqlite3*, BtCursor*, i64*);
+
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE int sqlite3BtreeCursorInfo(BtCursor*, int*, int);
+SQLITE_PRIVATE void sqlite3BtreeCursorList(Btree*);
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE   int sqlite3BtreeCheckpoint(Btree*, int, int *, int *);
+#endif
+
+SQLITE_PRIVATE int sqlite3BtreeTransferRow(BtCursor*, BtCursor*, i64);
+
+SQLITE_PRIVATE void sqlite3BtreeClearCache(Btree*);
+
+/*
+** If we are not using shared cache, then there is no need to
+** use mutexes to access the BtShared structures.  So make the
+** Enter and Leave procedures no-ops.
+*/
+#ifndef SQLITE_OMIT_SHARED_CACHE
+SQLITE_PRIVATE   void sqlite3BtreeEnter(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeEnterAll(sqlite3*);
+SQLITE_PRIVATE   int sqlite3BtreeSharable(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeEnterCursor(BtCursor*);
+SQLITE_PRIVATE   int sqlite3BtreeConnectionCount(Btree*);
+#else
+# define sqlite3BtreeEnter(X)
+# define sqlite3BtreeEnterAll(X)
+# define sqlite3BtreeSharable(X) 0
+# define sqlite3BtreeEnterCursor(X)
+# define sqlite3BtreeConnectionCount(X) 1
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
+SQLITE_PRIVATE   void sqlite3BtreeLeave(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeLeaveCursor(BtCursor*);
+SQLITE_PRIVATE   void sqlite3BtreeLeaveAll(sqlite3*);
+#ifndef NDEBUG
+  /* These routines are used inside assert() statements only. */
+SQLITE_PRIVATE   int sqlite3BtreeHoldsMutex(Btree*);
+SQLITE_PRIVATE   int sqlite3BtreeHoldsAllMutexes(sqlite3*);
+SQLITE_PRIVATE   int sqlite3SchemaMutexHeld(sqlite3*,int,Schema*);
+#endif
+#else
+
+# define sqlite3BtreeLeave(X)
+# define sqlite3BtreeLeaveCursor(X)
+# define sqlite3BtreeLeaveAll(X)
+
+# define sqlite3BtreeHoldsMutex(X) 1
+# define sqlite3BtreeHoldsAllMutexes(X) 1
+# define sqlite3SchemaMutexHeld(X,Y,Z) 1
+#endif
+
+
+#endif /* SQLITE_BTREE_H */
+
+/************** End of btree.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include vdbe.h in the middle of sqliteInt.h ******************/
+/************** Begin file vdbe.h ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Header file for the Virtual DataBase Engine (VDBE)
+**
+** This header defines the interface to the virtual database engine
+** or VDBE.  The VDBE implements an abstract machine that runs a
+** simple program to access and modify the underlying database.
+*/
+#ifndef SQLITE_VDBE_H
+#define SQLITE_VDBE_H
+/* #include <stdio.h> */
+
+/*
+** A single VDBE is an opaque structure named "Vdbe".  Only routines
+** in the source file sqliteVdbe.c are allowed to see the insides
+** of this structure.
+*/
+typedef struct Vdbe Vdbe;
+
+/*
+** The names of the following types declared in vdbeInt.h are required
+** for the VdbeOp definition.
+*/
+typedef struct sqlite3_value Mem;
+typedef struct SubProgram SubProgram;
+typedef struct SubrtnSig SubrtnSig;
+
+/*
+** A signature for a reusable subroutine that materializes the RHS of
+** an IN operator.
+*/
+struct SubrtnSig {
+  int selId;          /* SELECT-id for the SELECT statement on the RHS */
+  u8 bComplete;       /* True if fully coded and available for reusable */
+  char *zAff;         /* Affinity of the overall IN expression */
+  int iTable;         /* Ephemeral table generated by the subroutine */
+  int iAddr;          /* Subroutine entry address */
+  int regReturn;      /* Register used to hold return address */
+};
+
+/*
+** A single instruction of the virtual machine has an opcode
+** and as many as three operands.  The instruction is recorded
+** as an instance of the following structure:
+*/
+struct VdbeOp {
+  u8 opcode;          /* What operation to perform */
+  signed char p4type; /* One of the P4_xxx constants for p4 */
+  u16 p5;             /* Fifth parameter is an unsigned 16-bit integer */
+  int p1;             /* First operand */
+  int p2;             /* Second parameter (often the jump destination) */
+  int p3;             /* The third parameter */
+  union p4union {     /* fourth parameter */
+    int i;                 /* Integer value if p4type==P4_INT32 */
+    void *p;               /* Generic pointer */
+    char *z;               /* Pointer to data for string (char array) types */
+    i64 *pI64;             /* Used when p4type is P4_INT64 */
+    double *pReal;         /* Used when p4type is P4_REAL */
+    FuncDef *pFunc;        /* Used when p4type is P4_FUNCDEF */
+    sqlite3_context *pCtx; /* Used when p4type is P4_FUNCCTX */
+    CollSeq *pColl;        /* Used when p4type is P4_COLLSEQ */
+    Mem *pMem;             /* Used when p4type is P4_MEM */
+    VTable *pVtab;         /* Used when p4type is P4_VTAB */
+    KeyInfo *pKeyInfo;     /* Used when p4type is P4_KEYINFO */
+    u32 *ai;               /* Used when p4type is P4_INTARRAY */
+    SubProgram *pProgram;  /* Used when p4type is P4_SUBPROGRAM */
+    Table *pTab;           /* Used when p4type is P4_TABLE */
+    SubrtnSig *pSubrtnSig; /* Used when p4type is P4_SUBRTNSIG */
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+    Expr *pExpr;           /* Used when p4type is P4_EXPR */
+#endif
+  } p4;
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  char *zComment;          /* Comment to improve readability */
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  u32 iSrcLine;            /* Source-code line that generated this opcode
+                           ** with flags in the upper 8 bits */
+#endif
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
+  u64 nExec;
+  u64 nCycle;
+#endif
+};
+typedef struct VdbeOp VdbeOp;
+
+
+/*
+** A sub-routine used to implement a trigger program.
+*/
+struct SubProgram {
+  VdbeOp *aOp;                  /* Array of opcodes for sub-program */
+  int nOp;                      /* Elements in aOp[] */
+  int nMem;                     /* Number of memory cells required */
+  int nCsr;                     /* Number of cursors required */
+  u8 *aOnce;                    /* Array of OP_Once flags */
+  void *token;                  /* id that may be used to recursive triggers */
+  SubProgram *pNext;            /* Next sub-program already visited */
+};
+
+/*
+** A smaller version of VdbeOp used for the VdbeAddOpList() function because
+** it takes up less space.
+*/
+struct VdbeOpList {
+  u8 opcode;          /* What operation to perform */
+  signed char p1;     /* First operand */
+  signed char p2;     /* Second parameter (often the jump destination) */
+  signed char p3;     /* Third parameter */
+};
+typedef struct VdbeOpList VdbeOpList;
+
+/*
+** Allowed values of VdbeOp.p4type
+*/
+#define P4_NOTUSED      0   /* The P4 parameter is not used */
+#define P4_TRANSIENT    0   /* P4 is a pointer to a transient string */
+#define P4_STATIC     (-1)  /* Pointer to a static string */
+#define P4_COLLSEQ    (-2)  /* P4 is a pointer to a CollSeq structure */
+#define P4_INT32      (-3)  /* P4 is a 32-bit signed integer */
+#define P4_SUBPROGRAM (-4)  /* P4 is a pointer to a SubProgram structure */
+#define P4_TABLE      (-5)  /* P4 is a pointer to a Table structure */
+/* Above do not own any resources.  Must free those below */
+#define P4_FREE_IF_LE (-6)
+#define P4_DYNAMIC    (-6)  /* Pointer to memory from sqliteMalloc() */
+#define P4_FUNCDEF    (-7)  /* P4 is a pointer to a FuncDef structure */
+#define P4_KEYINFO    (-8)  /* P4 is a pointer to a KeyInfo structure */
+#define P4_EXPR       (-9) /* P4 is a pointer to an Expr tree */
+#define P4_MEM        (-10) /* P4 is a pointer to a Mem*    structure */
+#define P4_VTAB       (-11) /* P4 is a pointer to an sqlite3_vtab structure */
+#define P4_REAL       (-12) /* P4 is a 64-bit floating point value */
+#define P4_INT64      (-13) /* P4 is a 64-bit signed integer */
+#define P4_INTARRAY   (-14) /* P4 is a vector of 32-bit integers */
+#define P4_FUNCCTX    (-15) /* P4 is a pointer to an sqlite3_context object */
+#define P4_TABLEREF   (-16) /* Like P4_TABLE, but reference counted */
+#define P4_SUBRTNSIG  (-17) /* P4 is a SubrtnSig pointer */
+
+/* Error message codes for OP_Halt */
+#define P5_ConstraintNotNull 1
+#define P5_ConstraintUnique  2
+#define P5_ConstraintCheck   3
+#define P5_ConstraintFK      4
+
+/*
+** The Vdbe.aColName array contains 5n Mem structures, where n is the
+** number of columns of data returned by the statement.
+*/
+#define COLNAME_NAME     0
+#define COLNAME_DECLTYPE 1
+#define COLNAME_DATABASE 2
+#define COLNAME_TABLE    3
+#define COLNAME_COLUMN   4
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+# define COLNAME_N        5      /* Number of COLNAME_xxx symbols */
+#else
+# ifdef SQLITE_OMIT_DECLTYPE
+#   define COLNAME_N      1      /* Store only the name */
+# else
+#   define COLNAME_N      2      /* Store the name and decltype */
+# endif
+#endif
+
+/*
+** The following macro converts a label returned by sqlite3VdbeMakeLabel()
+** into an index into the Parse.aLabel[] array that contains the resolved
+** address of that label.
+*/
+#define ADDR(X)  (~(X))
+
+/*
+** The makefile scans the vdbe.c source file and creates the "opcodes.h"
+** header file that defines a number for each opcode used by the VDBE.
+*/
+/************** Include opcodes.h in the middle of vdbe.h ********************/
+/************** Begin file opcodes.h *****************************************/
+/* Automatically generated.  Do not edit */
+/* See the tool/mkopcodeh.tcl script for details */
+#define OP_Savepoint       0
+#define OP_AutoCommit      1
+#define OP_Transaction     2
+#define OP_Checkpoint      3
+#define OP_JournalMode     4
+#define OP_Vacuum          5
+#define OP_VFilter         6 /* jump, synopsis: iplan=r[P3] zplan='P4'     */
+#define OP_VUpdate         7 /* synopsis: data=r[P3@P2]                    */
+#define OP_Init            8 /* jump0, synopsis: Start at P2               */
+#define OP_Goto            9 /* jump                                       */
+#define OP_Gosub          10 /* jump                                       */
+#define OP_InitCoroutine  11 /* jump0                                      */
+#define OP_Yield          12 /* jump0                                      */
+#define OP_MustBeInt      13 /* jump0                                      */
+#define OP_Jump           14 /* jump                                       */
+#define OP_Once           15 /* jump                                       */
+#define OP_If             16 /* jump                                       */
+#define OP_IfNot          17 /* jump                                       */
+#define OP_IsType         18 /* jump, synopsis: if typeof(P1.P3) in P5 goto P2 */
+#define OP_Not            19 /* same as TK_NOT, synopsis: r[P2]= !r[P1]    */
+#define OP_IfNullRow      20 /* jump, synopsis: if P1.nullRow then r[P3]=NULL, goto P2 */
+#define OP_SeekLT         21 /* jump0, synopsis: key=r[P3@P4]              */
+#define OP_SeekLE         22 /* jump0, synopsis: key=r[P3@P4]              */
+#define OP_SeekGE         23 /* jump0, synopsis: key=r[P3@P4]              */
+#define OP_SeekGT         24 /* jump0, synopsis: key=r[P3@P4]              */
+#define OP_IfNotOpen      25 /* jump, synopsis: if( !csr[P1] ) goto P2     */
+#define OP_IfNoHope       26 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_NoConflict     27 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_NotFound       28 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_Found          29 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_SeekRowid      30 /* jump0, synopsis: intkey=r[P3]              */
+#define OP_NotExists      31 /* jump, synopsis: intkey=r[P3]               */
+#define OP_Last           32 /* jump0                                      */
+#define OP_IfSizeBetween  33 /* jump                                       */
+#define OP_SorterSort     34 /* jump                                       */
+#define OP_Sort           35 /* jump                                       */
+#define OP_Rewind         36 /* jump0                                      */
+#define OP_SorterNext     37 /* jump                                       */
+#define OP_Prev           38 /* jump                                       */
+#define OP_Next           39 /* jump                                       */
+#define OP_IdxLE          40 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_IdxGT          41 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_IdxLT          42 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_Or             43 /* same as TK_OR, synopsis: r[P3]=(r[P1] || r[P2]) */
+#define OP_And            44 /* same as TK_AND, synopsis: r[P3]=(r[P1] && r[P2]) */
+#define OP_IdxGE          45 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_RowSetRead     46 /* jump, synopsis: r[P3]=rowset(P1)           */
+#define OP_RowSetTest     47 /* jump, synopsis: if r[P3] in rowset(P1) goto P2 */
+#define OP_Program        48 /* jump0                                      */
+#define OP_FkIfZero       49 /* jump, synopsis: if fkctr[P1]==0 goto P2    */
+#define OP_IfPos          50 /* jump, synopsis: if r[P1]>0 then r[P1]-=P3, goto P2 */
+#define OP_IsNull         51 /* jump, same as TK_ISNULL, synopsis: if r[P1]==NULL goto P2 */
+#define OP_NotNull        52 /* jump, same as TK_NOTNULL, synopsis: if r[P1]!=NULL goto P2 */
+#define OP_Ne             53 /* jump, same as TK_NE, synopsis: IF r[P3]!=r[P1] */
+#define OP_Eq             54 /* jump, same as TK_EQ, synopsis: IF r[P3]==r[P1] */
+#define OP_Gt             55 /* jump, same as TK_GT, synopsis: IF r[P3]>r[P1] */
+#define OP_Le             56 /* jump, same as TK_LE, synopsis: IF r[P3]<=r[P1] */
+#define OP_Lt             57 /* jump, same as TK_LT, synopsis: IF r[P3]<r[P1] */
+#define OP_Ge             58 /* jump, same as TK_GE, synopsis: IF r[P3]>=r[P1] */
+#define OP_ElseEq         59 /* jump, same as TK_ESCAPE                    */
+#define OP_IfNotZero      60 /* jump, synopsis: if r[P1]!=0 then r[P1]--, goto P2 */
+#define OP_DecrJumpZero   61 /* jump, synopsis: if (--r[P1])==0 goto P2    */
+#define OP_IncrVacuum     62 /* jump                                       */
+#define OP_VNext          63 /* jump                                       */
+#define OP_Filter         64 /* jump, synopsis: if key(P3@P4) not in filter(P1) goto P2 */
+#define OP_PureFunc       65 /* synopsis: r[P3]=func(r[P2@NP])             */
+#define OP_Function       66 /* synopsis: r[P3]=func(r[P2@NP])             */
+#define OP_Return         67
+#define OP_EndCoroutine   68
+#define OP_HaltIfNull     69 /* synopsis: if r[P3]=null halt               */
+#define OP_Halt           70
+#define OP_Integer        71 /* synopsis: r[P2]=P1                         */
+#define OP_Int64          72 /* synopsis: r[P2]=P4                         */
+#define OP_String         73 /* synopsis: r[P2]='P4' (len=P1)              */
+#define OP_BeginSubrtn    74 /* synopsis: r[P2]=NULL                       */
+#define OP_Null           75 /* synopsis: r[P2..P3]=NULL                   */
+#define OP_SoftNull       76 /* synopsis: r[P1]=NULL                       */
+#define OP_Blob           77 /* synopsis: r[P2]=P4 (len=P1)                */
+#define OP_Variable       78 /* synopsis: r[P2]=parameter(P1)              */
+#define OP_Move           79 /* synopsis: r[P2@P3]=r[P1@P3]                */
+#define OP_Copy           80 /* synopsis: r[P2@P3+1]=r[P1@P3+1]            */
+#define OP_SCopy          81 /* synopsis: r[P2]=r[P1]                      */
+#define OP_IntCopy        82 /* synopsis: r[P2]=r[P1]                      */
+#define OP_FkCheck        83
+#define OP_ResultRow      84 /* synopsis: output=r[P1@P2]                  */
+#define OP_CollSeq        85
+#define OP_AddImm         86 /* synopsis: r[P1]=r[P1]+P2                   */
+#define OP_RealAffinity   87
+#define OP_Cast           88 /* synopsis: affinity(r[P1])                  */
+#define OP_Permutation    89
+#define OP_Compare        90 /* synopsis: r[P1@P3] <-> r[P2@P3]            */
+#define OP_IsTrue         91 /* synopsis: r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4 */
+#define OP_ZeroOrNull     92 /* synopsis: r[P2] = 0 OR NULL                */
+#define OP_Offset         93 /* synopsis: r[P3] = sqlite_offset(P1)        */
+#define OP_Column         94 /* synopsis: r[P3]=PX cursor P1 column P2     */
+#define OP_TypeCheck      95 /* synopsis: typecheck(r[P1@P2])              */
+#define OP_Affinity       96 /* synopsis: affinity(r[P1@P2])               */
+#define OP_MakeRecord     97 /* synopsis: r[P3]=mkrec(r[P1@P2])            */
+#define OP_Count          98 /* synopsis: r[P2]=count()                    */
+#define OP_ReadCookie     99
+#define OP_SetCookie     100
+#define OP_ReopenIdx     101 /* synopsis: root=P2 iDb=P3                   */
+#define OP_OpenRead      102 /* synopsis: root=P2 iDb=P3                   */
+#define OP_BitAnd        103 /* same as TK_BITAND, synopsis: r[P3]=r[P1]&r[P2] */
+#define OP_BitOr         104 /* same as TK_BITOR, synopsis: r[P3]=r[P1]|r[P2] */
+#define OP_ShiftLeft     105 /* same as TK_LSHIFT, synopsis: r[P3]=r[P2]<<r[P1] */
+#define OP_ShiftRight    106 /* same as TK_RSHIFT, synopsis: r[P3]=r[P2]>>r[P1] */
+#define OP_Add           107 /* same as TK_PLUS, synopsis: r[P3]=r[P1]+r[P2] */
+#define OP_Subtract      108 /* same as TK_MINUS, synopsis: r[P3]=r[P2]-r[P1] */
+#define OP_Multiply      109 /* same as TK_STAR, synopsis: r[P3]=r[P1]*r[P2] */
+#define OP_Divide        110 /* same as TK_SLASH, synopsis: r[P3]=r[P2]/r[P1] */
+#define OP_Remainder     111 /* same as TK_REM, synopsis: r[P3]=r[P2]%r[P1] */
+#define OP_Concat        112 /* same as TK_CONCAT, synopsis: r[P3]=r[P2]+r[P1] */
+#define OP_OpenWrite     113 /* synopsis: root=P2 iDb=P3                   */
+#define OP_OpenDup       114
+#define OP_BitNot        115 /* same as TK_BITNOT, synopsis: r[P2]= ~r[P1] */
+#define OP_OpenAutoindex 116 /* synopsis: nColumn=P2                       */
+#define OP_OpenEphemeral 117 /* synopsis: nColumn=P2                       */
+#define OP_String8       118 /* same as TK_STRING, synopsis: r[P2]='P4'    */
+#define OP_SorterOpen    119
+#define OP_SequenceTest  120 /* synopsis: if( cursor[P1].ctr++ ) pc = P2   */
+#define OP_OpenPseudo    121 /* synopsis: P3 columns in r[P2]              */
+#define OP_Close         122
+#define OP_ColumnsUsed   123
+#define OP_SeekScan      124 /* synopsis: Scan-ahead up to P1 rows         */
+#define OP_SeekHit       125 /* synopsis: set P2<=seekHit<=P3              */
+#define OP_Sequence      126 /* synopsis: r[P2]=cursor[P1].ctr++           */
+#define OP_NewRowid      127 /* synopsis: r[P2]=rowid                      */
+#define OP_Insert        128 /* synopsis: intkey=r[P3] data=r[P2]          */
+#define OP_RowCell       129
+#define OP_Delete        130
+#define OP_ResetCount    131
+#define OP_SorterCompare 132 /* synopsis: if key(P1)!=trim(r[P3],P4) goto P2 */
+#define OP_SorterData    133 /* synopsis: r[P2]=data                       */
+#define OP_RowData       134 /* synopsis: r[P2]=data                       */
+#define OP_Rowid         135 /* synopsis: r[P2]=PX rowid of P1             */
+#define OP_NullRow       136
+#define OP_SeekEnd       137
+#define OP_IdxInsert     138 /* synopsis: key=r[P2]                        */
+#define OP_SorterInsert  139 /* synopsis: key=r[P2]                        */
+#define OP_IdxDelete     140 /* synopsis: key=r[P2@P3]                     */
+#define OP_DeferredSeek  141 /* synopsis: Move P3 to P1.rowid if needed    */
+#define OP_IdxRowid      142 /* synopsis: r[P2]=rowid                      */
+#define OP_FinishSeek    143
+#define OP_Destroy       144
+#define OP_Clear         145
+#define OP_ResetSorter   146
+#define OP_CreateBtree   147 /* synopsis: r[P2]=root iDb=P1 flags=P3       */
+#define OP_SqlExec       148
+#define OP_ParseSchema   149
+#define OP_LoadAnalysis  150
+#define OP_DropTable     151
+#define OP_DropIndex     152
+#define OP_DropTrigger   153
+#define OP_Real          154 /* same as TK_FLOAT, synopsis: r[P2]=P4       */
+#define OP_IntegrityCk   155
+#define OP_RowSetAdd     156 /* synopsis: rowset(P1)=r[P2]                 */
+#define OP_Param         157
+#define OP_FkCounter     158 /* synopsis: fkctr[P1]+=P2                    */
+#define OP_MemMax        159 /* synopsis: r[P1]=max(r[P1],r[P2])           */
+#define OP_OffsetLimit   160 /* synopsis: if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1) */
+#define OP_AggInverse    161 /* synopsis: accum=r[P3] inverse(r[P2@P5])    */
+#define OP_AggStep       162 /* synopsis: accum=r[P3] step(r[P2@P5])       */
+#define OP_AggStep1      163 /* synopsis: accum=r[P3] step(r[P2@P5])       */
+#define OP_AggValue      164 /* synopsis: r[P3]=value N=P2                 */
+#define OP_AggFinal      165 /* synopsis: accum=r[P1] N=P2                 */
+#define OP_Expire        166
+#define OP_CursorLock    167
+#define OP_CursorUnlock  168
+#define OP_TableLock     169 /* synopsis: iDb=P1 root=P2 write=P3          */
+#define OP_VBegin        170
+#define OP_VCreate       171
+#define OP_VDestroy      172
+#define OP_VOpen         173
+#define OP_VCheck        174
+#define OP_VInitIn       175 /* synopsis: r[P2]=ValueList(P1,P3)           */
+#define OP_VColumn       176 /* synopsis: r[P3]=vcolumn(P2)                */
+#define OP_VRename       177
+#define OP_Pagecount     178
+#define OP_MaxPgcnt      179
+#define OP_ClrSubtype    180 /* synopsis: r[P1].subtype = 0                */
+#define OP_GetSubtype    181 /* synopsis: r[P2] = r[P1].subtype            */
+#define OP_SetSubtype    182 /* synopsis: r[P2].subtype = r[P1]            */
+#define OP_FilterAdd     183 /* synopsis: filter(P1) += key(P3@P4)         */
+#define OP_Trace         184
+#define OP_CursorHint    185
+#define OP_ReleaseReg    186 /* synopsis: release r[P1@P2] mask P3         */
+#define OP_Noop          187
+#define OP_Explain       188
+#define OP_Abortable     189
+
+/* Properties such as "out2" or "jump" that are specified in
+** comments following the "case" for each opcode in the vdbe.c
+** are encoded into bitvectors as follows:
+*/
+#define OPFLG_JUMP        0x01  /* jump:  P2 holds jmp target */
+#define OPFLG_IN1         0x02  /* in1:   P1 is an input */
+#define OPFLG_IN2         0x04  /* in2:   P2 is an input */
+#define OPFLG_IN3         0x08  /* in3:   P3 is an input */
+#define OPFLG_OUT2        0x10  /* out2:  P2 is an output */
+#define OPFLG_OUT3        0x20  /* out3:  P3 is an output */
+#define OPFLG_NCYCLE      0x40  /* ncycle:Cycles count against P1 */
+#define OPFLG_JUMP0       0x80  /* jump0:  P2 might be zero */
+#define OPFLG_INITIALIZER {\
+/*   0 */ 0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0x41, 0x00,\
+/*   8 */ 0x81, 0x01, 0x01, 0x81, 0x83, 0x83, 0x01, 0x01,\
+/*  16 */ 0x03, 0x03, 0x01, 0x12, 0x01, 0xc9, 0xc9, 0xc9,\
+/*  24 */ 0xc9, 0x01, 0x49, 0x49, 0x49, 0x49, 0xc9, 0x49,\
+/*  32 */ 0xc1, 0x01, 0x41, 0x41, 0xc1, 0x01, 0x41, 0x41,\
+/*  40 */ 0x41, 0x41, 0x41, 0x26, 0x26, 0x41, 0x23, 0x0b,\
+/*  48 */ 0x81, 0x01, 0x03, 0x03, 0x03, 0x0b, 0x0b, 0x0b,\
+/*  56 */ 0x0b, 0x0b, 0x0b, 0x01, 0x03, 0x03, 0x01, 0x41,\
+/*  64 */ 0x01, 0x00, 0x00, 0x02, 0x02, 0x08, 0x00, 0x10,\
+/*  72 */ 0x10, 0x10, 0x00, 0x10, 0x00, 0x10, 0x10, 0x00,\
+/*  80 */ 0x00, 0x10, 0x10, 0x00, 0x00, 0x00, 0x02, 0x02,\
+/*  88 */ 0x02, 0x00, 0x00, 0x12, 0x1e, 0x20, 0x40, 0x00,\
+/*  96 */ 0x00, 0x00, 0x10, 0x10, 0x00, 0x40, 0x40, 0x26,\
+/* 104 */ 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x26,\
+/* 112 */ 0x26, 0x00, 0x40, 0x12, 0x40, 0x40, 0x10, 0x00,\
+/* 120 */ 0x00, 0x00, 0x40, 0x00, 0x40, 0x40, 0x10, 0x10,\
+/* 128 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x50,\
+/* 136 */ 0x00, 0x40, 0x04, 0x04, 0x00, 0x40, 0x50, 0x40,\
+/* 144 */ 0x10, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00,\
+/* 152 */ 0x00, 0x00, 0x10, 0x00, 0x06, 0x10, 0x00, 0x04,\
+/* 160 */ 0x1a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
+/* 168 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x10, 0x50,\
+/* 176 */ 0x40, 0x00, 0x10, 0x10, 0x02, 0x12, 0x12, 0x00,\
+/* 184 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,}
+
+/* The resolve3P2Values() routine is able to run faster if it knows
+** the value of the largest JUMP opcode.  The smaller the maximum
+** JUMP opcode the better, so the mkopcodeh.tcl script that
+** generated this include file strives to group all JUMP opcodes
+** together near the beginning of the list.
+*/
+#define SQLITE_MX_JUMP_OPCODE  64  /* Maximum JUMP opcode */
+
+/************** End of opcodes.h *********************************************/
+/************** Continuing where we left off in vdbe.h ***********************/
+
+/*
+** Additional non-public SQLITE_PREPARE_* flags
+*/
+#define SQLITE_PREPARE_SAVESQL  0x80  /* Preserve SQL text */
+#define SQLITE_PREPARE_MASK     0x1f  /* Mask of public flags */
+
+/*
+** Prototypes for the VDBE interface.  See comments on the implementation
+** for a description of what each of these routines does.
+*/
+SQLITE_PRIVATE Vdbe *sqlite3VdbeCreate(Parse*);
+SQLITE_PRIVATE Parse *sqlite3VdbeParser(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeAddOp0(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp1(Vdbe*,int,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp2(Vdbe*,int,int,int);
+SQLITE_PRIVATE int sqlite3VdbeGoto(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeLoadString(Vdbe*,int,const char*);
+SQLITE_PRIVATE void sqlite3VdbeMultiLoad(Vdbe*,int,const char*,...);
+SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp4(Vdbe*,int,int,int,int,const char *zP4,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Dup8(Vdbe*,int,int,int,int,const u8*,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Int(Vdbe*,int,int,int,int,int);
+SQLITE_PRIVATE int sqlite3VdbeAddFunctionCall(Parse*,int,int,int,int,const FuncDef*,int);
+SQLITE_PRIVATE void sqlite3VdbeEndCoroutine(Vdbe*,int);
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_TEST_REALLOC_STRESS)
+SQLITE_PRIVATE   void sqlite3VdbeVerifyNoMallocRequired(Vdbe *p, int N);
+SQLITE_PRIVATE   void sqlite3VdbeVerifyNoResultRow(Vdbe *p);
+#else
+# define sqlite3VdbeVerifyNoMallocRequired(A,B)
+# define sqlite3VdbeVerifyNoResultRow(A)
+#endif
+#if defined(SQLITE_DEBUG)
+SQLITE_PRIVATE   void sqlite3VdbeVerifyAbortable(Vdbe *p, int);
+SQLITE_PRIVATE   void sqlite3VdbeNoJumpsOutsideSubrtn(Vdbe*,int,int,int);
+#else
+# define sqlite3VdbeVerifyAbortable(A,B)
+# define sqlite3VdbeNoJumpsOutsideSubrtn(A,B,C,D)
+#endif
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp,int iLineno);
+#ifndef SQLITE_OMIT_EXPLAIN
+SQLITE_PRIVATE   int sqlite3VdbeExplain(Parse*,u8,const char*,...);
+SQLITE_PRIVATE   void sqlite3VdbeExplainPop(Parse*);
+SQLITE_PRIVATE   int sqlite3VdbeExplainParent(Parse*);
+# define ExplainQueryPlan(P)        sqlite3VdbeExplain P
+# ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+#  define ExplainQueryPlan2(V,P)     (V = sqlite3VdbeExplain P)
+# else
+#  define ExplainQueryPlan2(V,P)     ExplainQueryPlan(P)
+# endif
+# define ExplainQueryPlanPop(P)     sqlite3VdbeExplainPop(P)
+# define ExplainQueryPlanParent(P)  sqlite3VdbeExplainParent(P)
+#else
+# define ExplainQueryPlan(P)
+# define ExplainQueryPlan2(V,P)
+# define ExplainQueryPlanPop(P)
+# define ExplainQueryPlanParent(P) 0
+# define sqlite3ExplainBreakpoint(A,B) /*no-op*/
+#endif
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_EXPLAIN)
+SQLITE_PRIVATE   void sqlite3ExplainBreakpoint(const char*,const char*);
+#else
+# define sqlite3ExplainBreakpoint(A,B) /*no-op*/
+#endif
+SQLITE_PRIVATE void sqlite3VdbeAddParseSchemaOp(Vdbe*, int, char*, u16);
+SQLITE_PRIVATE void sqlite3VdbeChangeOpcode(Vdbe*, int addr, u8);
+SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
+SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
+SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe*, int addr, int P3);
+SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe*, u16 P5);
+SQLITE_PRIVATE void sqlite3VdbeTypeofColumn(Vdbe*, int);
+SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe*, int addr);
+SQLITE_PRIVATE void sqlite3VdbeJumpHereOrPopInst(Vdbe*, int addr);
+SQLITE_PRIVATE int sqlite3VdbeChangeToNoop(Vdbe*, int addr);
+SQLITE_PRIVATE int sqlite3VdbeDeletePriorOpcode(Vdbe*, u8 op);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3VdbeReleaseRegisters(Parse*,int addr, int n, u32 mask, int);
+#else
+# define sqlite3VdbeReleaseRegisters(P,A,N,M,F)
+#endif
+SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
+SQLITE_PRIVATE void sqlite3VdbeAppendP4(Vdbe*, void *pP4, int p4type);
+SQLITE_PRIVATE void sqlite3VdbeSetP4KeyInfo(Parse*, Index*);
+SQLITE_PRIVATE void sqlite3VdbeUsesBtree(Vdbe*, int);
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetLastOp(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeMakeLabel(Parse*);
+SQLITE_PRIVATE void sqlite3VdbeRunOnlyOnce(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeReusable(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeMakeReady(Vdbe*,Parse*);
+SQLITE_PRIVATE int sqlite3VdbeFinalize(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe*, int);
+SQLITE_PRIVATE int sqlite3VdbeCurrentAddr(Vdbe*);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   int sqlite3VdbeAssertMayAbort(Vdbe *, int);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeResetStepResult(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeRewind(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeReset(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, void(*)(void*));
+SQLITE_PRIVATE void sqlite3VdbeCountChanges(Vdbe*);
+SQLITE_PRIVATE sqlite3 *sqlite3VdbeDb(Vdbe*);
+SQLITE_PRIVATE u8 sqlite3VdbePrepareFlags(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe*, const char *z, int n, u8);
+#ifdef SQLITE_ENABLE_NORMALIZE
+SQLITE_PRIVATE void sqlite3VdbeAddDblquoteStr(sqlite3*,Vdbe*,const char*);
+SQLITE_PRIVATE int sqlite3VdbeUsesDoubleQuotedString(Vdbe*,const char*);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe*,Vdbe*);
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeTakeOpArray(Vdbe*, int*, int*);
+SQLITE_PRIVATE sqlite3_value *sqlite3VdbeGetBoundValue(Vdbe*, int, u8);
+SQLITE_PRIVATE void sqlite3VdbeSetVarmask(Vdbe*, int);
+#ifndef SQLITE_OMIT_TRACE
+SQLITE_PRIVATE   char *sqlite3VdbeExpandSql(Vdbe*, const char*);
+#endif
+SQLITE_PRIVATE int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
+SQLITE_PRIVATE int sqlite3BlobCompare(const Mem*, const Mem*);
+
+SQLITE_PRIVATE void sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,UnpackedRecord*);
+SQLITE_PRIVATE int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);
+SQLITE_PRIVATE int sqlite3VdbeRecordCompareWithSkip(int, const void *, UnpackedRecord *, int);
+SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(KeyInfo*);
+
+typedef int (*RecordCompare)(int,const void*,UnpackedRecord*);
+SQLITE_PRIVATE RecordCompare sqlite3VdbeFindCompare(UnpackedRecord*);
+
+SQLITE_PRIVATE void sqlite3VdbeLinkSubProgram(Vdbe *, SubProgram *);
+SQLITE_PRIVATE int sqlite3VdbeHasSubProgram(Vdbe*);
+
+SQLITE_PRIVATE void sqlite3MemSetArrayInt64(sqlite3_value *aMem, int iIdx, i64 val);
+
+SQLITE_PRIVATE int sqlite3NotPureFunc(sqlite3_context*);
+#ifdef SQLITE_ENABLE_BYTECODE_VTAB
+SQLITE_PRIVATE int sqlite3VdbeBytecodeVtabInit(sqlite3*);
+#endif
+
+/* Use SQLITE_ENABLE_COMMENTS to enable generation of extra comments on
+** each VDBE opcode.
+**
+** Use the SQLITE_ENABLE_MODULE_COMMENTS macro to see some extra no-op
+** comments in VDBE programs that show key decision points in the code
+** generator.
+*/
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+SQLITE_PRIVATE   void sqlite3VdbeComment(Vdbe*, const char*, ...);
+# define VdbeComment(X)  sqlite3VdbeComment X
+SQLITE_PRIVATE   void sqlite3VdbeNoopComment(Vdbe*, const char*, ...);
+# define VdbeNoopComment(X)  sqlite3VdbeNoopComment X
+# ifdef SQLITE_ENABLE_MODULE_COMMENTS
+#   define VdbeModuleComment(X)  sqlite3VdbeNoopComment X
+# else
+#   define VdbeModuleComment(X)
+# endif
+#else
+# define VdbeComment(X)
+# define VdbeNoopComment(X)
+# define VdbeModuleComment(X)
+#endif
+
+/*
+** The VdbeCoverage macros are used to set a coverage testing point
+** for VDBE branch instructions.  The coverage testing points are line
+** numbers in the sqlite3.c source file.  VDBE branch coverage testing
+** only works with an amalgamation build.  That's ok since a VDBE branch
+** coverage build designed for testing the test suite only.  No application
+** should ever ship with VDBE branch coverage measuring turned on.
+**
+**    VdbeCoverage(v)                  // Mark the previously coded instruction
+**                                     // as a branch
+**
+**    VdbeCoverageIf(v, conditional)   // Mark previous if conditional true
+**
+**    VdbeCoverageAlwaysTaken(v)       // Previous branch is always taken
+**
+**    VdbeCoverageNeverTaken(v)        // Previous branch is never taken
+**
+**    VdbeCoverageNeverNull(v)         // Previous three-way branch is only
+**                                     // taken on the first two ways.  The
+**                                     // NULL option is not possible
+**
+**    VdbeCoverageEqNe(v)              // Previous OP_Jump is only interested
+**                                     // in distinguishing equal and not-equal.
+**
+** Every VDBE branch operation must be tagged with one of the macros above.
+** If not, then when "make test" is run with -DSQLITE_VDBE_COVERAGE and
+** -DSQLITE_DEBUG then an ALWAYS() will fail in the vdbeTakeBranch()
+** routine in vdbe.c, alerting the developer to the missed tag.
+**
+** During testing, the test application will invoke
+** sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE,...) to set a callback
+** routine that is invoked as each bytecode branch is taken.  The callback
+** contains the sqlite3.c source line number of the VdbeCoverage macro and
+** flags to indicate whether or not the branch was taken.  The test application
+** is responsible for keeping track of this and reporting byte-code branches
+** that are never taken.
+**
+** See the VdbeBranchTaken() macro and vdbeTakeBranch() function in the
+** vdbe.c source file for additional information.
+*/
+#ifdef SQLITE_VDBE_COVERAGE
+SQLITE_PRIVATE   void sqlite3VdbeSetLineNumber(Vdbe*,int);
+# define VdbeCoverage(v) sqlite3VdbeSetLineNumber(v,__LINE__)
+# define VdbeCoverageIf(v,x) if(x)sqlite3VdbeSetLineNumber(v,__LINE__)
+# define VdbeCoverageAlwaysTaken(v) \
+         sqlite3VdbeSetLineNumber(v,__LINE__|0x5000000);
+# define VdbeCoverageNeverTaken(v) \
+         sqlite3VdbeSetLineNumber(v,__LINE__|0x6000000);
+# define VdbeCoverageNeverNull(v) \
+         sqlite3VdbeSetLineNumber(v,__LINE__|0x4000000);
+# define VdbeCoverageNeverNullIf(v,x) \
+         if(x)sqlite3VdbeSetLineNumber(v,__LINE__|0x4000000);
+# define VdbeCoverageEqNe(v) \
+         sqlite3VdbeSetLineNumber(v,__LINE__|0x8000000);
+# define VDBE_OFFSET_LINENO(x) (__LINE__+x)
+#else
+# define VdbeCoverage(v)
+# define VdbeCoverageIf(v,x)
+# define VdbeCoverageAlwaysTaken(v)
+# define VdbeCoverageNeverTaken(v)
+# define VdbeCoverageNeverNull(v)
+# define VdbeCoverageNeverNullIf(v,x)
+# define VdbeCoverageEqNe(v)
+# define VDBE_OFFSET_LINENO(x) 0
+#endif
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+SQLITE_PRIVATE void sqlite3VdbeScanStatus(Vdbe*, int, int, int, LogEst, const char*);
+SQLITE_PRIVATE void sqlite3VdbeScanStatusRange(Vdbe*, int, int, int);
+SQLITE_PRIVATE void sqlite3VdbeScanStatusCounters(Vdbe*, int, int, int);
+#else
+# define sqlite3VdbeScanStatus(a,b,c,d,e,f)
+# define sqlite3VdbeScanStatusRange(a,b,c,d)
+# define sqlite3VdbeScanStatusCounters(a,b,c,d)
+#endif
+
+#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
+SQLITE_PRIVATE void sqlite3VdbePrintOp(FILE*, int, VdbeOp*);
+#endif
+
+#if defined(SQLITE_ENABLE_CURSOR_HINTS) && defined(SQLITE_DEBUG)
+SQLITE_PRIVATE int sqlite3CursorRangeHintExprCheck(Walker *pWalker, Expr *pExpr);
+#endif
+
+#endif /* SQLITE_VDBE_H */
+
+/************** End of vdbe.h ************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include pcache.h in the middle of sqliteInt.h ****************/
+/************** Begin file pcache.h ******************************************/
+/*
+** 2008 August 05
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite page cache
+** subsystem.
+*/
+
+#ifndef _PCACHE_H_
+
+typedef struct PgHdr PgHdr;
+typedef struct PCache PCache;
+
+/*
+** Every page in the cache is controlled by an instance of the following
+** structure.
+*/
+struct PgHdr {
+  sqlite3_pcache_page *pPage;    /* Pcache object page handle */
+  void *pData;                   /* Page data */
+  void *pExtra;                  /* Extra content */
+  PCache *pCache;                /* PRIVATE: Cache that owns this page */
+  PgHdr *pDirty;                 /* Transient list of dirty sorted by pgno */
+  Pager *pPager;                 /* The pager this page is part of */
+  Pgno pgno;                     /* Page number for this page */
+#ifdef SQLITE_CHECK_PAGES
+  u32 pageHash;                  /* Hash of page content */
+#endif
+  u16 flags;                     /* PGHDR flags defined below */
+
+  /**********************************************************************
+  ** Elements above, except pCache, are public.  All that follow are
+  ** private to pcache.c and should not be accessed by other modules.
+  ** pCache is grouped with the public elements for efficiency.
+  */
+  i64 nRef;                      /* Number of users of this page */
+  PgHdr *pDirtyNext;             /* Next element in list of dirty pages */
+  PgHdr *pDirtyPrev;             /* Previous element in list of dirty pages */
+                          /* NB: pDirtyNext and pDirtyPrev are undefined if the
+                          ** PgHdr object is not dirty */
+};
+
+/* Bit values for PgHdr.flags */
+#define PGHDR_CLEAN           0x001  /* Page not on the PCache.pDirty list */
+#define PGHDR_DIRTY           0x002  /* Page is on the PCache.pDirty list */
+#define PGHDR_WRITEABLE       0x004  /* Journaled and ready to modify */
+#define PGHDR_NEED_SYNC       0x008  /* Fsync the rollback journal before
+                                     ** writing this page to the database */
+#define PGHDR_DONT_WRITE      0x010  /* Do not write content to disk */
+#define PGHDR_MMAP            0x020  /* This is an mmap page object */
+
+#define PGHDR_WAL_APPEND      0x040  /* Appended to wal file */
+
+/* Initialize and shutdown the page cache subsystem */
+SQLITE_PRIVATE int sqlite3PcacheInitialize(void);
+SQLITE_PRIVATE void sqlite3PcacheShutdown(void);
+
+/* Page cache buffer management:
+** These routines implement SQLITE_CONFIG_PAGECACHE.
+*/
+SQLITE_PRIVATE void sqlite3PCacheBufferSetup(void *, int sz, int n);
+
+/* Create a new pager cache.
+** Under memory stress, invoke xStress to try to make pages clean.
+** Only clean and unpinned pages can be reclaimed.
+*/
+SQLITE_PRIVATE int sqlite3PcacheOpen(
+  int szPage,                    /* Size of every page */
+  int szExtra,                   /* Extra space associated with each page */
+  int bPurgeable,                /* True if pages are on backing store */
+  int (*xStress)(void*, PgHdr*), /* Call to try to make pages clean */
+  void *pStress,                 /* Argument to xStress */
+  PCache *pToInit                /* Preallocated space for the PCache */
+);
+
+/* Modify the page-size after the cache has been created. */
+SQLITE_PRIVATE int sqlite3PcacheSetPageSize(PCache *, int);
+
+/* Return the size in bytes of a PCache object.  Used to preallocate
+** storage space.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSize(void);
+
+/* One release per successful fetch.  Page is pinned until released.
+** Reference counted.
+*/
+SQLITE_PRIVATE sqlite3_pcache_page *sqlite3PcacheFetch(PCache*, Pgno, int createFlag);
+SQLITE_PRIVATE int sqlite3PcacheFetchStress(PCache*, Pgno, sqlite3_pcache_page**);
+SQLITE_PRIVATE PgHdr *sqlite3PcacheFetchFinish(PCache*, Pgno, sqlite3_pcache_page *pPage);
+SQLITE_PRIVATE void sqlite3PcacheRelease(PgHdr*);
+
+SQLITE_PRIVATE void sqlite3PcacheDrop(PgHdr*);         /* Remove page from cache */
+SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr*);    /* Make sure page is marked dirty */
+SQLITE_PRIVATE void sqlite3PcacheMakeClean(PgHdr*);    /* Mark a single page as clean */
+SQLITE_PRIVATE void sqlite3PcacheCleanAll(PCache*);    /* Mark all dirty list pages as clean */
+SQLITE_PRIVATE void sqlite3PcacheClearWritable(PCache*);
+
+/* Change a page number.  Used by incr-vacuum. */
+SQLITE_PRIVATE void sqlite3PcacheMove(PgHdr*, Pgno);
+
+/* Remove all pages with pgno>x.  Reset the cache if x==0 */
+SQLITE_PRIVATE void sqlite3PcacheTruncate(PCache*, Pgno x);
+
+/* Get a list of all dirty pages in the cache, sorted by page number */
+SQLITE_PRIVATE PgHdr *sqlite3PcacheDirtyList(PCache*);
+
+/* Reset and close the cache object */
+SQLITE_PRIVATE void sqlite3PcacheClose(PCache*);
+
+/* Clear flags from pages of the page cache */
+SQLITE_PRIVATE void sqlite3PcacheClearSyncFlags(PCache *);
+
+/* Discard the contents of the cache */
+SQLITE_PRIVATE void sqlite3PcacheClear(PCache*);
+
+/* Return the total number of outstanding page references */
+SQLITE_PRIVATE i64 sqlite3PcacheRefCount(PCache*);
+
+/* Increment the reference count of an existing page */
+SQLITE_PRIVATE void sqlite3PcacheRef(PgHdr*);
+
+SQLITE_PRIVATE i64 sqlite3PcachePageRefcount(PgHdr*);
+
+/* Return the total number of pages stored in the cache */
+SQLITE_PRIVATE int sqlite3PcachePagecount(PCache*);
+
+#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
+/* Iterate through all dirty pages currently stored in the cache. This
+** interface is only available if SQLITE_CHECK_PAGES is defined when the
+** library is built.
+*/
+SQLITE_PRIVATE void sqlite3PcacheIterateDirty(PCache *pCache, void (*xIter)(PgHdr *));
+#endif
+
+#if defined(SQLITE_DEBUG)
+/* Check invariants on a PgHdr object */
+SQLITE_PRIVATE int sqlite3PcachePageSanity(PgHdr*);
+#endif
+
+/* Set and get the suggested cache-size for the specified pager-cache.
+**
+** If no global maximum is configured, then the system attempts to limit
+** the total number of pages cached by purgeable pager-caches to the sum
+** of the suggested cache-sizes.
+*/
+SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *, int);
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *);
+#endif
+
+/* Set or get the suggested spill-size for the specified pager-cache.
+**
+** The spill-size is the minimum number of pages in cache before the cache
+** will attempt to spill dirty pages by calling xStress.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSetSpillsize(PCache *, int);
+
+/* Free up as much memory as possible from the page cache */
+SQLITE_PRIVATE void sqlite3PcacheShrink(PCache*);
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/* Try to return memory used by the pcache module to the main memory heap */
+SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int);
+#endif
+
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE void sqlite3PcacheStats(int*,int*,int*,int*);
+#endif
+
+SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
+
+/* Return the header size */
+SQLITE_PRIVATE int sqlite3HeaderSizePcache(void);
+SQLITE_PRIVATE int sqlite3HeaderSizePcache1(void);
+
+/* Number of dirty pages as a percentage of the configured cache size */
+SQLITE_PRIVATE int sqlite3PCachePercentDirty(PCache*);
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+SQLITE_PRIVATE int sqlite3PCacheIsDirty(PCache *pCache);
+#endif
+
+#endif /* _PCACHE_H_ */
+
+/************** End of pcache.h **********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include mutex.h in the middle of sqliteInt.h *****************/
+/************** Begin file mutex.h *******************************************/
+/*
+** 2007 August 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the common header for all mutex implementations.
+** The sqliteInt.h header #includes this file so that it is available
+** to all source files.  We break it out in an effort to keep the code
+** better organized.
+**
+** NOTE:  source files should *not* #include this header file directly.
+** Source files should #include the sqliteInt.h file and let that file
+** include this one indirectly.
+*/
+
+
+/*
+** Figure out what version of the code to use.  The choices are
+**
+**   SQLITE_MUTEX_OMIT         No mutex logic.  Not even stubs.  The
+**                             mutexes implementation cannot be overridden
+**                             at start-time.
+**
+**   SQLITE_MUTEX_NOOP         For single-threaded applications.  No
+**                             mutual exclusion is provided.  But this
+**                             implementation can be overridden at
+**                             start-time.
+**
+**   SQLITE_MUTEX_PTHREADS     For multi-threaded applications on Unix.
+**
+**   SQLITE_MUTEX_W32          For multi-threaded applications on Win32.
+*/
+#if !SQLITE_THREADSAFE
+# define SQLITE_MUTEX_OMIT
+#endif
+#if SQLITE_THREADSAFE && !defined(SQLITE_MUTEX_NOOP)
+#  if SQLITE_OS_UNIX
+#    define SQLITE_MUTEX_PTHREADS
+#  elif SQLITE_OS_WIN
+#    define SQLITE_MUTEX_W32
+#  else
+#    define SQLITE_MUTEX_NOOP
+#  endif
+#endif
+
+#ifdef SQLITE_MUTEX_OMIT
+/*
+** If this is a no-op implementation, implement everything as macros.
+*/
+#define sqlite3_mutex_alloc(X)    ((sqlite3_mutex*)8)
+#define sqlite3_mutex_free(X)
+#define sqlite3_mutex_enter(X)
+#define sqlite3_mutex_try(X)      SQLITE_OK
+#define sqlite3_mutex_leave(X)
+#define sqlite3_mutex_held(X)     ((void)(X),1)
+#define sqlite3_mutex_notheld(X)  ((void)(X),1)
+#define sqlite3MutexAlloc(X)      ((sqlite3_mutex*)8)
+#define sqlite3MutexInit()        SQLITE_OK
+#define sqlite3MutexEnd()
+#define MUTEX_LOGIC(X)
+#else
+#define MUTEX_LOGIC(X)            X
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
+#endif /* defined(SQLITE_MUTEX_OMIT) */
+
+/************** End of mutex.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/* The SQLITE_EXTRA_DURABLE compile-time option used to set the default
+** synchronous setting to EXTRA.  It is no longer supported.
+*/
+#ifdef SQLITE_EXTRA_DURABLE
+# warning Use SQLITE_DEFAULT_SYNCHRONOUS=3 instead of SQLITE_EXTRA_DURABLE
+# define SQLITE_DEFAULT_SYNCHRONOUS 3
+#endif
+
+/*
+** Default synchronous levels.
+**
+** Note that (for historical reasons) the PAGER_SYNCHRONOUS_* macros differ
+** from the SQLITE_DEFAULT_SYNCHRONOUS value by 1.
+**
+**           PAGER_SYNCHRONOUS       DEFAULT_SYNCHRONOUS
+**   OFF           1                         0
+**   NORMAL        2                         1
+**   FULL          3                         2
+**   EXTRA         4                         3
+**
+** The "PRAGMA synchronous" statement also uses the zero-based numbers.
+** In other words, the zero-based numbers are used for all external interfaces
+** and the one-based values are used internally.
+*/
+#ifndef SQLITE_DEFAULT_SYNCHRONOUS
+# define SQLITE_DEFAULT_SYNCHRONOUS 2
+#endif
+#ifndef SQLITE_DEFAULT_WAL_SYNCHRONOUS
+# define SQLITE_DEFAULT_WAL_SYNCHRONOUS SQLITE_DEFAULT_SYNCHRONOUS
+#endif
+
+/*
+** Each database file to be accessed by the system is an instance
+** of the following structure.  There are normally two of these structures
+** in the sqlite.aDb[] array.  aDb[0] is the main database file and
+** aDb[1] is the database file used to hold temporary tables.  Additional
+** databases may be attached.
+*/
+struct Db {
+  char *zDbSName;      /* Name of this database. (schema name, not filename) */
+  Btree *pBt;          /* The B*Tree structure for this database file */
+  u8 safety_level;     /* How aggressive at syncing data to disk */
+  u8 bSyncSet;         /* True if "PRAGMA synchronous=N" has been run */
+  Schema *pSchema;     /* Pointer to database schema (possibly shared) */
+};
+
+/*
+** An instance of the following structure stores a database schema.
+**
+** Most Schema objects are associated with a Btree.  The exception is
+** the Schema for the TEMP database (sqlite3.aDb[1]) which is free-standing.
+** In shared cache mode, a single Schema object can be shared by multiple
+** Btrees that refer to the same underlying BtShared object.
+**
+** Schema objects are automatically deallocated when the last Btree that
+** references them is destroyed.   The TEMP Schema is manually freed by
+** sqlite3_close().
+*
+** A thread must be holding a mutex on the corresponding Btree in order
+** to access Schema content.  This implies that the thread must also be
+** holding a mutex on the sqlite3 connection pointer that owns the Btree.
+** For a TEMP Schema, only the connection mutex is required.
+*/
+struct Schema {
+  int schema_cookie;   /* Database schema version number for this file */
+  int iGeneration;     /* Generation counter.  Incremented with each change */
+  Hash tblHash;        /* All tables indexed by name */
+  Hash idxHash;        /* All (named) indices indexed by name */
+  Hash trigHash;       /* All triggers indexed by name */
+  Hash fkeyHash;       /* All foreign keys by referenced table name */
+  Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
+  u8 file_format;      /* Schema format version for this file */
+  u8 enc;              /* Text encoding used by this database */
+  u16 schemaFlags;     /* Flags associated with this schema */
+  int cache_size;      /* Number of pages to use in the cache */
+};
+
+/*
+** These macros can be used to test, set, or clear bits in the
+** Db.pSchema->flags field.
+*/
+#define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->schemaFlags&(P))==(P))
+#define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].pSchema->schemaFlags&(P))!=0)
+#define DbSetProperty(D,I,P)     (D)->aDb[I].pSchema->schemaFlags|=(P)
+#define DbClearProperty(D,I,P)   (D)->aDb[I].pSchema->schemaFlags&=~(P)
+
+/*
+** Allowed values for the DB.pSchema->flags field.
+**
+** The DB_SchemaLoaded flag is set after the database schema has been
+** read into internal hash tables.
+**
+** DB_UnresetViews means that one or more views have column names that
+** have been filled out.  If the schema changes, these column names might
+** changes and so the view will need to be reset.
+*/
+#define DB_SchemaLoaded    0x0001  /* The schema has been loaded */
+#define DB_UnresetViews    0x0002  /* Some views have defined column names */
+#define DB_ResetWanted     0x0008  /* Reset the schema when nSchemaLock==0 */
+
+/*
+** The number of different kinds of things that can be limited
+** using the sqlite3_limit() interface.
+*/
+#define SQLITE_N_LIMIT (SQLITE_LIMIT_WORKER_THREADS+1)
+
+/*
+** Lookaside malloc is a set of fixed-size buffers that can be used
+** to satisfy small transient memory allocation requests for objects
+** associated with a particular database connection.  The use of
+** lookaside malloc provides a significant performance enhancement
+** (approx 10%) by avoiding numerous malloc/free requests while parsing
+** SQL statements.
+**
+** The Lookaside structure holds configuration information about the
+** lookaside malloc subsystem.  Each available memory allocation in
+** the lookaside subsystem is stored on a linked list of LookasideSlot
+** objects.
+**
+** Lookaside allocations are only allowed for objects that are associated
+** with a particular database connection.  Hence, schema information cannot
+** be stored in lookaside because in shared cache mode the schema information
+** is shared by multiple database connections.  Therefore, while parsing
+** schema information, the Lookaside.bEnabled flag is cleared so that
+** lookaside allocations are not used to construct the schema objects.
+**
+** New lookaside allocations are only allowed if bDisable==0.  When
+** bDisable is greater than zero, sz is set to zero which effectively
+** disables lookaside without adding a new test for the bDisable flag
+** in a performance-critical path.  sz should be set by to szTrue whenever
+** bDisable changes back to zero.
+**
+** Lookaside buffers are initially held on the pInit list.  As they are
+** used and freed, they are added back to the pFree list.  New allocations
+** come off of pFree first, then pInit as a fallback.  This dual-list
+** allows use to compute a high-water mark - the maximum number of allocations
+** outstanding at any point in the past - by subtracting the number of
+** allocations on the pInit list from the total number of allocations.
+**
+** Enhancement on 2019-12-12:  Two-size-lookaside
+** The default lookaside configuration is 100 slots of 1200 bytes each.
+** The larger slot sizes are important for performance, but they waste
+** a lot of space, as most lookaside allocations are less than 128 bytes.
+** The two-size-lookaside enhancement breaks up the lookaside allocation
+** into two pools:  One of 128-byte slots and the other of the default size
+** (1200-byte) slots.   Allocations are filled from the small-pool first,
+** failing over to the full-size pool if that does not work.  Thus more
+** lookaside slots are available while also using less memory.
+** This enhancement can be omitted by compiling with
+** SQLITE_OMIT_TWOSIZE_LOOKASIDE.
+*/
+struct Lookaside {
+  u32 bDisable;           /* Only operate the lookaside when zero */
+  u16 sz;                 /* Size of each buffer in bytes */
+  u16 szTrue;             /* True value of sz, even if disabled */
+  u8 bMalloced;           /* True if pStart obtained from sqlite3_malloc() */
+  u32 nSlot;              /* Number of lookaside slots allocated */
+  u32 anStat[3];          /* 0: hits.  1: size misses.  2: full misses */
+  LookasideSlot *pInit;   /* List of buffers not previously used */
+  LookasideSlot *pFree;   /* List of available buffers */
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  LookasideSlot *pSmallInit; /* List of small buffers not previously used */
+  LookasideSlot *pSmallFree; /* List of available small buffers */
+  void *pMiddle;          /* First byte past end of full-size buffers and
+                          ** the first byte of LOOKASIDE_SMALL buffers */
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+  void *pStart;           /* First byte of available memory space */
+  void *pEnd;             /* First byte past end of available space */
+  void *pTrueEnd;         /* True value of pEnd, when db->pnBytesFreed!=0 */
+};
+struct LookasideSlot {
+  LookasideSlot *pNext;    /* Next buffer in the list of free buffers */
+};
+
+#define DisableLookaside  db->lookaside.bDisable++;db->lookaside.sz=0
+#define EnableLookaside   db->lookaside.bDisable--;\
+   db->lookaside.sz=db->lookaside.bDisable?0:db->lookaside.szTrue
+
+/* Size of the smaller allocations in two-size lookaside */
+#ifdef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+#  define LOOKASIDE_SMALL           0
+#else
+#  define LOOKASIDE_SMALL         128
+#endif
+
+/*
+** A hash table for built-in function definitions.  (Application-defined
+** functions use a regular table table from hash.h.)
+**
+** Hash each FuncDef structure into one of the FuncDefHash.a[] slots.
+** Collisions are on the FuncDef.u.pHash chain.  Use the SQLITE_FUNC_HASH()
+** macro to compute a hash on the function name.
+*/
+#define SQLITE_FUNC_HASH_SZ 23
+struct FuncDefHash {
+  FuncDef *a[SQLITE_FUNC_HASH_SZ];       /* Hash table for functions */
+};
+#define SQLITE_FUNC_HASH(C,L) (((C)+(L))%SQLITE_FUNC_HASH_SZ)
+
+/*
+** typedef for the authorization callback function.
+*/
+typedef int (*sqlite3_xauth)(void*,int,const char*,const char*,const char*,
+                             const char*);
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/* This is an extra SQLITE_TRACE macro that indicates "legacy" tracing
+** in the style of sqlite3_trace()
+*/
+#define SQLITE_TRACE_LEGACY          0x40     /* Use the legacy xTrace */
+#define SQLITE_TRACE_XPROFILE        0x80     /* Use the legacy xProfile */
+#else
+#define SQLITE_TRACE_LEGACY          0
+#define SQLITE_TRACE_XPROFILE        0
+#endif /* SQLITE_OMIT_DEPRECATED */
+#define SQLITE_TRACE_NONLEGACY_MASK  0x0f     /* Normal flags */
+
+/*
+** Maximum number of sqlite3.aDb[] entries.  This is the number of attached
+** databases plus 2 for "main" and "temp".
+*/
+#define SQLITE_MAX_DB (SQLITE_MAX_ATTACHED+2)
+
+/*
+** Each database connection is an instance of the following structure.
+*/
+struct sqlite3 {
+  sqlite3_vfs *pVfs;            /* OS Interface */
+  struct Vdbe *pVdbe;           /* List of active virtual machines */
+  CollSeq *pDfltColl;           /* BINARY collseq for the database encoding */
+  sqlite3_mutex *mutex;         /* Connection mutex */
+  Db *aDb;                      /* All backends */
+  int nDb;                      /* Number of backends currently in use */
+  u32 mDbFlags;                 /* flags recording internal state */
+  u64 flags;                    /* flags settable by pragmas. See below */
+  i64 lastRowid;                /* ROWID of most recent insert (see above) */
+  i64 szMmap;                   /* Default mmap_size setting */
+  u32 nSchemaLock;              /* Do not reset the schema when non-zero */
+  unsigned int openFlags;       /* Flags passed to sqlite3_vfs.xOpen() */
+  int errCode;                  /* Most recent error code (SQLITE_*) */
+  int errByteOffset;            /* Byte offset of error in SQL statement */
+  int errMask;                  /* & result codes with this before returning */
+  int iSysErrno;                /* Errno value from last system error */
+  u32 dbOptFlags;               /* Flags to enable/disable optimizations */
+  u8 enc;                       /* Text encoding */
+  u8 autoCommit;                /* The auto-commit flag. */
+  u8 temp_store;                /* 1: file 2: memory 0: default */
+  u8 mallocFailed;              /* True if we have seen a malloc failure */
+  u8 bBenignMalloc;             /* Do not require OOMs if true */
+  u8 dfltLockMode;              /* Default locking-mode for attached dbs */
+  signed char nextAutovac;      /* Autovac setting after VACUUM if >=0 */
+  u8 suppressErr;               /* Do not issue error messages if true */
+  u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */
+  u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
+  u8 mTrace;                    /* zero or more SQLITE_TRACE flags */
+  u8 noSharedCache;             /* True if no shared-cache backends */
+  u8 nSqlExec;                  /* Number of pending OP_SqlExec opcodes */
+  u8 eOpenState;                /* Current condition of the connection */
+  int nextPagesize;             /* Pagesize after VACUUM if >0 */
+  i64 nChange;                  /* Value returned by sqlite3_changes() */
+  i64 nTotalChange;             /* Value returned by sqlite3_total_changes() */
+  int aLimit[SQLITE_N_LIMIT];   /* Limits */
+  int nMaxSorterMmap;           /* Maximum size of regions mapped by sorter */
+  struct sqlite3InitInfo {      /* Information used during initialization */
+    Pgno newTnum;               /* Rootpage of table being initialized */
+    u8 iDb;                     /* Which db file is being initialized */
+    u8 busy;                    /* TRUE if currently initializing */
+    unsigned orphanTrigger : 1; /* Last statement is orphaned TEMP trigger */
+    unsigned imposterTable : 1; /* Building an imposter table */
+    unsigned reopenMemdb : 1;   /* ATTACH is really a reopen using MemDB */
+    const char **azInit;        /* "type", "name", and "tbl_name" columns */
+  } init;
+  int nVdbeActive;              /* Number of VDBEs currently running */
+  int nVdbeRead;                /* Number of active VDBEs that read or write */
+  int nVdbeWrite;               /* Number of active VDBEs that read and write */
+  int nVdbeExec;                /* Number of nested calls to VdbeExec() */
+  int nVDestroy;                /* Number of active OP_VDestroy operations */
+  int nExtension;               /* Number of loaded extensions */
+  void **aExtension;            /* Array of shared library handles */
+  union {
+    void (*xLegacy)(void*,const char*);   /* mTrace==SQLITE_TRACE_LEGACY */
+    int (*xV2)(u32,void*,void*,void*);    /* All other mTrace values */
+  } trace;
+  void *pTraceArg;                        /* Argument to the trace function */
+#ifndef SQLITE_OMIT_DEPRECATED
+  void (*xProfile)(void*,const char*,u64);  /* Profiling function */
+  void *pProfileArg;                        /* Argument to profile function */
+#endif
+  void *pCommitArg;                 /* Argument to xCommitCallback() */
+  int (*xCommitCallback)(void*);    /* Invoked at every commit. */
+  void *pRollbackArg;               /* Argument to xRollbackCallback() */
+  void (*xRollbackCallback)(void*); /* Invoked at every commit. */
+  void *pUpdateArg;
+  void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);
+  void *pAutovacPagesArg;           /* Client argument to autovac_pages */
+  void (*xAutovacDestr)(void*);     /* Destructor for pAutovacPAgesArg */
+  unsigned int (*xAutovacPages)(void*,const char*,u32,u32,u32);
+  Parse *pParse;                /* Current parse */
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  void *pPreUpdateArg;          /* First argument to xPreUpdateCallback */
+  void (*xPreUpdateCallback)(   /* Registered using sqlite3_preupdate_hook() */
+    void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64
+  );
+  PreUpdate *pPreUpdate;        /* Context for active pre-update callback */
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+#ifndef SQLITE_OMIT_WAL
+  int (*xWalCallback)(void *, sqlite3 *, const char *, int);
+  void *pWalArg;
+#endif
+  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
+  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
+  void *pCollNeededArg;
+  sqlite3_value *pErr;          /* Most recent error message */
+  union {
+    volatile int isInterrupted; /* True if sqlite3_interrupt has been called */
+    double notUsed1;            /* Spacer */
+  } u1;
+  Lookaside lookaside;          /* Lookaside malloc configuration */
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth;          /* Access authorization function */
+  void *pAuthArg;               /* 1st argument to the access auth function */
+#endif
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  int (*xProgress)(void *);     /* The progress callback */
+  void *pProgressArg;           /* Argument to the progress callback */
+  unsigned nProgressOps;        /* Number of opcodes for progress callback */
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  int nVTrans;                  /* Allocated size of aVTrans */
+  Hash aModule;                 /* populated by sqlite3_create_module() */
+  VtabCtx *pVtabCtx;            /* Context for active vtab connect/create */
+  VTable **aVTrans;             /* Virtual tables with open transactions */
+  VTable *pDisconnect;          /* Disconnect these in next sqlite3_prepare() */
+#endif
+  Hash aFunc;                   /* Hash table of connection functions */
+  Hash aCollSeq;                /* All collating sequences */
+  BusyHandler busyHandler;      /* Busy callback */
+  Db aDbStatic[2];              /* Static space for the 2 default backends */
+  Savepoint *pSavepoint;        /* List of active savepoints */
+  int nAnalysisLimit;           /* Number of index rows to ANALYZE */
+  int busyTimeout;              /* Busy handler timeout, in msec */
+  int nSavepoint;               /* Number of non-transaction savepoints */
+  int nStatement;               /* Number of nested statement-transactions  */
+  i64 nDeferredCons;            /* Net deferred constraints this transaction. */
+  i64 nDeferredImmCons;         /* Net deferred immediate constraints */
+  int *pnBytesFreed;            /* If not NULL, increment this in DbFree() */
+  DbClientData *pDbData;        /* sqlite3_set_clientdata() content */
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+  /* The following variables are all protected by the STATIC_MAIN
+  ** mutex, not by sqlite3.mutex. They are used by code in notify.c.
+  **
+  ** When X.pUnlockConnection==Y, that means that X is waiting for Y to
+  ** unlock so that it can proceed.
+  **
+  ** When X.pBlockingConnection==Y, that means that something that X tried
+  ** tried to do recently failed with an SQLITE_LOCKED error due to locks
+  ** held by Y.
+  */
+  sqlite3 *pBlockingConnection; /* Connection that caused SQLITE_LOCKED */
+  sqlite3 *pUnlockConnection;           /* Connection to watch for unlock */
+  void *pUnlockArg;                     /* Argument to xUnlockNotify */
+  void (*xUnlockNotify)(void **, int);  /* Unlock notify callback */
+  sqlite3 *pNextBlocked;        /* Next in list of all blocked connections */
+#endif
+};
+
+/*
+** A macro to discover the encoding of a database.
+*/
+#define SCHEMA_ENC(db) ((db)->aDb[0].pSchema->enc)
+#define ENC(db)        ((db)->enc)
+
+/*
+** A u64 constant where the lower 32 bits are all zeros.  Only the
+** upper 32 bits are included in the argument.  Necessary because some
+** C-compilers still do not accept LL integer literals.
+*/
+#define HI(X)  ((u64)(X)<<32)
+
+/*
+** Possible values for the sqlite3.flags.
+**
+** Value constraints (enforced via assert()):
+**      SQLITE_FullFSync     == PAGER_FULLFSYNC
+**      SQLITE_CkptFullFSync == PAGER_CKPT_FULLFSYNC
+**      SQLITE_CacheSpill    == PAGER_CACHE_SPILL
+*/
+#define SQLITE_WriteSchema    0x00000001  /* OK to update SQLITE_SCHEMA */
+#define SQLITE_LegacyFileFmt  0x00000002  /* Create new databases in format 1 */
+#define SQLITE_FullColNames   0x00000004  /* Show full column names on SELECT */
+#define SQLITE_FullFSync      0x00000008  /* Use full fsync on the backend */
+#define SQLITE_CkptFullFSync  0x00000010  /* Use full fsync for checkpoint */
+#define SQLITE_CacheSpill     0x00000020  /* OK to spill pager cache */
+#define SQLITE_ShortColNames  0x00000040  /* Show short columns names */
+#define SQLITE_TrustedSchema  0x00000080  /* Allow unsafe functions and
+                                          ** vtabs in the schema definition */
+#define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */
+                                          /*   result set is empty */
+#define SQLITE_IgnoreChecks   0x00000200  /* Do not enforce check constraints */
+#define SQLITE_StmtScanStatus 0x00000400  /* Enable stmt_scanstats() counters */
+#define SQLITE_NoCkptOnClose  0x00000800  /* No checkpoint on close()/DETACH */
+#define SQLITE_ReverseOrder   0x00001000  /* Reverse unordered SELECTs */
+#define SQLITE_RecTriggers    0x00002000  /* Enable recursive triggers */
+#define SQLITE_ForeignKeys    0x00004000  /* Enforce foreign key constraints  */
+#define SQLITE_AutoIndex      0x00008000  /* Enable automatic indexes */
+#define SQLITE_LoadExtension  0x00010000  /* Enable load_extension */
+#define SQLITE_LoadExtFunc    0x00020000  /* Enable load_extension() SQL func */
+#define SQLITE_EnableTrigger  0x00040000  /* True to enable triggers */
+#define SQLITE_DeferFKs       0x00080000  /* Defer all FK constraints */
+#define SQLITE_QueryOnly      0x00100000  /* Disable database changes */
+#define SQLITE_CellSizeCk     0x00200000  /* Check btree cell sizes on load */
+#define SQLITE_Fts3Tokenizer  0x00400000  /* Enable fts3_tokenizer(2) */
+#define SQLITE_EnableQPSG     0x00800000  /* Query Planner Stability Guarantee*/
+#define SQLITE_TriggerEQP     0x01000000  /* Show trigger EXPLAIN QUERY PLAN */
+#define SQLITE_ResetDatabase  0x02000000  /* Reset the database */
+#define SQLITE_LegacyAlter    0x04000000  /* Legacy ALTER TABLE behaviour */
+#define SQLITE_NoSchemaError  0x08000000  /* Do not report schema parse errors*/
+#define SQLITE_Defensive      0x10000000  /* Input SQL is likely hostile */
+#define SQLITE_DqsDDL         0x20000000  /* dbl-quoted strings allowed in DDL*/
+#define SQLITE_DqsDML         0x40000000  /* dbl-quoted strings allowed in DML*/
+#define SQLITE_EnableView     0x80000000  /* Enable the use of views */
+#define SQLITE_CountRows      HI(0x00001) /* Count rows changed by INSERT, */
+                                          /*   DELETE, or UPDATE and return */
+                                          /*   the count using a callback. */
+#define SQLITE_CorruptRdOnly  HI(0x00002) /* Prohibit writes due to error */
+#define SQLITE_ReadUncommit   HI(0x00004) /* READ UNCOMMITTED in shared-cache */
+#define SQLITE_FkNoAction     HI(0x00008) /* Treat all FK as NO ACTION */
+#define SQLITE_AttachCreate   HI(0x00010) /* ATTACH allowed to create new dbs */
+#define SQLITE_AttachWrite    HI(0x00020) /* ATTACH allowed to open for write */
+#define SQLITE_Comments       HI(0x00040) /* Enable SQL comments */
+
+/* Flags used only if debugging */
+#ifdef SQLITE_DEBUG
+#define SQLITE_SqlTrace       HI(0x0100000) /* Debug print SQL as it executes */
+#define SQLITE_VdbeListing    HI(0x0200000) /* Debug listings of VDBE progs */
+#define SQLITE_VdbeTrace      HI(0x0400000) /* True to trace VDBE execution */
+#define SQLITE_VdbeAddopTrace HI(0x0800000) /* Trace sqlite3VdbeAddOp() calls */
+#define SQLITE_VdbeEQP        HI(0x1000000) /* Debug EXPLAIN QUERY PLAN */
+#define SQLITE_ParserTrace    HI(0x2000000) /* PRAGMA parser_trace=ON */
+#endif
+
+/*
+** Allowed values for sqlite3.mDbFlags
+*/
+#define DBFLAG_SchemaChange   0x0001  /* Uncommitted Hash table changes */
+#define DBFLAG_PreferBuiltin  0x0002  /* Preference to built-in funcs */
+#define DBFLAG_Vacuum         0x0004  /* Currently in a VACUUM */
+#define DBFLAG_VacuumInto     0x0008  /* Currently running VACUUM INTO */
+#define DBFLAG_SchemaKnownOk  0x0010  /* Schema is known to be valid */
+#define DBFLAG_InternalFunc   0x0020  /* Allow use of internal functions */
+#define DBFLAG_EncodingFixed  0x0040  /* No longer possible to change enc. */
+
+/*
+** Bits of the sqlite3.dbOptFlags field that are used by the
+** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface to
+** selectively disable various optimizations.
+*/
+#define SQLITE_QueryFlattener 0x00000001 /* Query flattening */
+#define SQLITE_WindowFunc     0x00000002 /* Use xInverse for window functions */
+#define SQLITE_GroupByOrder   0x00000004 /* GROUPBY cover of ORDERBY */
+#define SQLITE_FactorOutConst 0x00000008 /* Constant factoring */
+#define SQLITE_DistinctOpt    0x00000010 /* DISTINCT using indexes */
+#define SQLITE_CoverIdxScan   0x00000020 /* Covering index scans */
+#define SQLITE_OrderByIdxJoin 0x00000040 /* ORDER BY of joins via index */
+#define SQLITE_Transitive     0x00000080 /* Transitive constraints */
+#define SQLITE_OmitNoopJoin   0x00000100 /* Omit unused tables in joins */
+#define SQLITE_CountOfView    0x00000200 /* The count-of-view optimization */
+#define SQLITE_CursorHints    0x00000400 /* Add OP_CursorHint opcodes */
+#define SQLITE_Stat4          0x00000800 /* Use STAT4 data */
+   /* TH3 expects this value  ^^^^^^^^^^ to be 0x0000800. Don't change it */
+#define SQLITE_PushDown       0x00001000 /* WHERE-clause push-down opt */
+#define SQLITE_SimplifyJoin   0x00002000 /* Convert LEFT JOIN to JOIN */
+#define SQLITE_SkipScan       0x00004000 /* Skip-scans */
+#define SQLITE_PropagateConst 0x00008000 /* The constant propagation opt */
+#define SQLITE_MinMaxOpt      0x00010000 /* The min/max optimization */
+#define SQLITE_SeekScan       0x00020000 /* The OP_SeekScan optimization */
+#define SQLITE_OmitOrderBy    0x00040000 /* Omit pointless ORDER BY */
+   /* TH3 expects this value  ^^^^^^^^^^ to be 0x40000. Coordinate any change */
+#define SQLITE_BloomFilter    0x00080000 /* Use a Bloom filter on searches */
+#define SQLITE_BloomPulldown  0x00100000 /* Run Bloom filters early */
+#define SQLITE_BalancedMerge  0x00200000 /* Balance multi-way merges */
+#define SQLITE_ReleaseReg     0x00400000 /* Use OP_ReleaseReg for testing */
+#define SQLITE_FlttnUnionAll  0x00800000 /* Disable the UNION ALL flattener */
+   /* TH3 expects this value  ^^^^^^^^^^ See flatten04.test */
+#define SQLITE_IndexedExpr    0x01000000 /* Pull exprs from index when able */
+#define SQLITE_Coroutines     0x02000000 /* Co-routines for subqueries */
+#define SQLITE_NullUnusedCols 0x04000000 /* NULL unused columns in subqueries */
+#define SQLITE_OnePass        0x08000000 /* Single-pass DELETE and UPDATE */
+#define SQLITE_OrderBySubq    0x10000000 /* ORDER BY in subquery helps outer */
+#define SQLITE_StarQuery      0x20000000 /* Heurists for star queries */
+#define SQLITE_AllOpts        0xffffffff /* All optimizations */
+
+/*
+** Macros for testing whether or not optimizations are enabled or disabled.
+*/
+#define OptimizationDisabled(db, mask)  (((db)->dbOptFlags&(mask))!=0)
+#define OptimizationEnabled(db, mask)   (((db)->dbOptFlags&(mask))==0)
+
+/*
+** Return true if it OK to factor constant expressions into the initialization
+** code. The argument is a Parse object for the code generator.
+*/
+#define ConstFactorOk(P) ((P)->okConstFactor)
+
+/* Possible values for the sqlite3.eOpenState field.
+** The numbers are randomly selected such that a minimum of three bits must
+** change to convert any number to another or to zero
+*/
+#define SQLITE_STATE_OPEN     0x76  /* Database is open */
+#define SQLITE_STATE_CLOSED   0xce  /* Database is closed */
+#define SQLITE_STATE_SICK     0xba  /* Error and awaiting close */
+#define SQLITE_STATE_BUSY     0x6d  /* Database currently in use */
+#define SQLITE_STATE_ERROR    0xd5  /* An SQLITE_MISUSE error occurred */
+#define SQLITE_STATE_ZOMBIE   0xa7  /* Close with last statement close */
+
+/*
+** Each SQL function is defined by an instance of the following
+** structure.  For global built-in functions (ex: substr(), max(), count())
+** a pointer to this structure is held in the sqlite3BuiltinFunctions object.
+** For per-connection application-defined functions, a pointer to this
+** structure is held in the db->aHash hash table.
+**
+** The u.pHash field is used by the global built-ins.  The u.pDestructor
+** field is used by per-connection app-def functions.
+*/
+struct FuncDef {
+  i16 nArg;            /* Number of arguments.  -1 means unlimited */
+  u32 funcFlags;       /* Some combination of SQLITE_FUNC_* */
+  void *pUserData;     /* User data parameter */
+  FuncDef *pNext;      /* Next function with same name */
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value**); /* func or agg-step */
+  void (*xFinalize)(sqlite3_context*);                  /* Agg finalizer */
+  void (*xValue)(sqlite3_context*);                     /* Current agg value */
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value**); /* inverse agg-step */
+  const char *zName;   /* SQL name of the function. */
+  union {
+    FuncDef *pHash;      /* Next with a different name but the same hash */
+    FuncDestructor *pDestructor;   /* Reference counted destructor function */
+  } u; /* pHash if SQLITE_FUNC_BUILTIN, pDestructor otherwise */
+};
+
+/*
+** This structure encapsulates a user-function destructor callback (as
+** configured using create_function_v2()) and a reference counter. When
+** create_function_v2() is called to create a function with a destructor,
+** a single object of this type is allocated. FuncDestructor.nRef is set to
+** the number of FuncDef objects created (either 1 or 3, depending on whether
+** or not the specified encoding is SQLITE_ANY). The FuncDef.pDestructor
+** member of each of the new FuncDef objects is set to point to the allocated
+** FuncDestructor.
+**
+** Thereafter, when one of the FuncDef objects is deleted, the reference
+** count on this object is decremented. When it reaches 0, the destructor
+** is invoked and the FuncDestructor structure freed.
+*/
+struct FuncDestructor {
+  int nRef;
+  void (*xDestroy)(void *);
+  void *pUserData;
+};
+
+/*
+** Possible values for FuncDef.flags.  Note that the _LENGTH and _TYPEOF
+** values must correspond to OPFLAG_LENGTHARG and OPFLAG_TYPEOFARG.  And
+** SQLITE_FUNC_CONSTANT must be the same as SQLITE_DETERMINISTIC.  There
+** are assert() statements in the code to verify this.
+**
+** Value constraints (enforced via assert()):
+**     SQLITE_FUNC_MINMAX      ==  NC_MinMaxAgg      == SF_MinMaxAgg
+**     SQLITE_FUNC_ANYORDER    ==  NC_OrderAgg       == SF_OrderByReqd
+**     SQLITE_FUNC_LENGTH      ==  OPFLAG_LENGTHARG
+**     SQLITE_FUNC_TYPEOF      ==  OPFLAG_TYPEOFARG
+**     SQLITE_FUNC_BYTELEN     ==  OPFLAG_BYTELENARG
+**     SQLITE_FUNC_CONSTANT    ==  SQLITE_DETERMINISTIC from the API
+**     SQLITE_FUNC_DIRECT      ==  SQLITE_DIRECTONLY from the API
+**     SQLITE_FUNC_UNSAFE      ==  SQLITE_INNOCUOUS  -- opposite meanings!!!
+**     SQLITE_FUNC_ENCMASK   depends on SQLITE_UTF* macros in the API
+**
+** Note that even though SQLITE_FUNC_UNSAFE and SQLITE_INNOCUOUS have the
+** same bit value, their meanings are inverted.  SQLITE_FUNC_UNSAFE is
+** used internally and if set means that the function has side effects.
+** SQLITE_INNOCUOUS is used by application code and means "not unsafe".
+** See multiple instances of tag-20230109-1.
+*/
+#define SQLITE_FUNC_ENCMASK  0x0003 /* SQLITE_UTF8, SQLITE_UTF16BE or UTF16LE */
+#define SQLITE_FUNC_LIKE     0x0004 /* Candidate for the LIKE optimization */
+#define SQLITE_FUNC_CASE     0x0008 /* Case-sensitive LIKE-type function */
+#define SQLITE_FUNC_EPHEM    0x0010 /* Ephemeral.  Delete with VDBE */
+#define SQLITE_FUNC_NEEDCOLL 0x0020 /* sqlite3GetFuncCollSeq() might be called*/
+#define SQLITE_FUNC_LENGTH   0x0040 /* Built-in length() function */
+#define SQLITE_FUNC_TYPEOF   0x0080 /* Built-in typeof() function */
+#define SQLITE_FUNC_BYTELEN  0x00c0 /* Built-in octet_length() function */
+#define SQLITE_FUNC_COUNT    0x0100 /* Built-in count(*) aggregate */
+/*                           0x0200 -- available for reuse */
+#define SQLITE_FUNC_UNLIKELY 0x0400 /* Built-in unlikely() function */
+#define SQLITE_FUNC_CONSTANT 0x0800 /* Constant inputs give a constant output */
+#define SQLITE_FUNC_MINMAX   0x1000 /* True for min() and max() aggregates */
+#define SQLITE_FUNC_SLOCHNG  0x2000 /* "Slow Change". Value constant during a
+                                    ** single query - might change over time */
+#define SQLITE_FUNC_TEST     0x4000 /* Built-in testing functions */
+#define SQLITE_FUNC_RUNONLY  0x8000 /* Cannot be used by valueFromFunction */
+#define SQLITE_FUNC_WINDOW   0x00010000 /* Built-in window-only function */
+#define SQLITE_FUNC_INTERNAL 0x00040000 /* For use by NestedParse() only */
+#define SQLITE_FUNC_DIRECT   0x00080000 /* Not for use in TRIGGERs or VIEWs */
+/* SQLITE_SUBTYPE            0x00100000 // Consumer of subtypes */
+#define SQLITE_FUNC_UNSAFE   0x00200000 /* Function has side effects */
+#define SQLITE_FUNC_INLINE   0x00400000 /* Functions implemented in-line */
+#define SQLITE_FUNC_BUILTIN  0x00800000 /* This is a built-in function */
+/*  SQLITE_RESULT_SUBTYPE    0x01000000 // Generator of subtypes */
+#define SQLITE_FUNC_ANYORDER 0x08000000 /* count/min/max aggregate */
+
+/* Identifier numbers for each in-line function */
+#define INLINEFUNC_coalesce             0
+#define INLINEFUNC_implies_nonnull_row  1
+#define INLINEFUNC_expr_implies_expr    2
+#define INLINEFUNC_expr_compare         3
+#define INLINEFUNC_affinity             4
+#define INLINEFUNC_iif                  5
+#define INLINEFUNC_sqlite_offset        6
+#define INLINEFUNC_unlikely            99  /* Default case */
+
+/*
+** The following three macros, FUNCTION(), LIKEFUNC() and AGGREGATE() are
+** used to create the initializers for the FuncDef structures.
+**
+**   FUNCTION(zName, nArg, iArg, bNC, xFunc)
+**     Used to create a scalar function definition of a function zName
+**     implemented by C function xFunc that accepts nArg arguments. The
+**     value passed as iArg is cast to a (void*) and made available
+**     as the user-data (sqlite3_user_data()) for the function. If
+**     argument bNC is true, then the SQLITE_FUNC_NEEDCOLL flag is set.
+**
+**   VFUNCTION(zName, nArg, iArg, bNC, xFunc)
+**     Like FUNCTION except it omits the SQLITE_FUNC_CONSTANT flag.
+**
+**   SFUNCTION(zName, nArg, iArg, bNC, xFunc)
+**     Like FUNCTION except it omits the SQLITE_FUNC_CONSTANT flag and
+**     adds the SQLITE_DIRECTONLY flag.
+**
+**   INLINE_FUNC(zName, nArg, iFuncId, mFlags)
+**     zName is the name of a function that is implemented by in-line
+**     byte code rather than by the usual callbacks. The iFuncId
+**     parameter determines the function id.  The mFlags parameter is
+**     optional SQLITE_FUNC_ flags for this function.
+**
+**   TEST_FUNC(zName, nArg, iFuncId, mFlags)
+**     zName is the name of a test-only function implemented by in-line
+**     byte code rather than by the usual callbacks. The iFuncId
+**     parameter determines the function id.  The mFlags parameter is
+**     optional SQLITE_FUNC_ flags for this function.
+**
+**   DFUNCTION(zName, nArg, iArg, bNC, xFunc)
+**     Like FUNCTION except it omits the SQLITE_FUNC_CONSTANT flag and
+**     adds the SQLITE_FUNC_SLOCHNG flag.  Used for date & time functions
+**     and functions like sqlite_version() that can change, but not during
+**     a single query.  The iArg is ignored.  The user-data is always set
+**     to a NULL pointer.  The bNC parameter is not used.
+**
+**   MFUNCTION(zName, nArg, xPtr, xFunc)
+**     For math-library functions.  xPtr is an arbitrary pointer.
+**
+**   PURE_DATE(zName, nArg, iArg, bNC, xFunc)
+**     Used for "pure" date/time functions, this macro is like DFUNCTION
+**     except that it does set the SQLITE_FUNC_CONSTANT flags.  iArg is
+**     ignored and the user-data for these functions is set to an
+**     arbitrary non-NULL pointer.  The bNC parameter is not used.
+**
+**   AGGREGATE(zName, nArg, iArg, bNC, xStep, xFinal)
+**     Used to create an aggregate function definition implemented by
+**     the C functions xStep and xFinal. The first four parameters
+**     are interpreted in the same way as the first 4 parameters to
+**     FUNCTION().
+**
+**   WAGGREGATE(zName, nArg, iArg, xStep, xFinal, xValue, xInverse)
+**     Used to create an aggregate function definition implemented by
+**     the C functions xStep and xFinal. The first four parameters
+**     are interpreted in the same way as the first 4 parameters to
+**     FUNCTION().
+**
+**   LIKEFUNC(zName, nArg, pArg, flags)
+**     Used to create a scalar function definition of a function zName
+**     that accepts nArg arguments and is implemented by a call to C
+**     function likeFunc. Argument pArg is cast to a (void *) and made
+**     available as the function user-data (sqlite3_user_data()). The
+**     FuncDef.flags variable is set to the value passed as the flags
+**     parameter.
+*/
+#define FUNCTION(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_FUNC_CONSTANT|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, 0, #zName, {0} }
+#define VFUNCTION(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, 0, #zName, {0} }
+#define SFUNCTION(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_DIRECTONLY|SQLITE_FUNC_UNSAFE, \
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, 0, #zName, {0} }
+#define MFUNCTION(zName, nArg, xPtr, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_FUNC_CONSTANT|SQLITE_UTF8, \
+   xPtr, 0, xFunc, 0, 0, 0, #zName, {0} }
+#define JFUNCTION(zName, nArg, bUseCache, bWS, bRS, bJsonB, iArg, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_DETERMINISTIC|SQLITE_FUNC_CONSTANT|\
+   SQLITE_UTF8|((bUseCache)*SQLITE_FUNC_RUNONLY)|\
+   ((bRS)*SQLITE_SUBTYPE)|((bWS)*SQLITE_RESULT_SUBTYPE), \
+   SQLITE_INT_TO_PTR(iArg|((bJsonB)*JSON_BLOB)),0,xFunc,0, 0, 0, #zName, {0} }
+#define INLINE_FUNC(zName, nArg, iArg, mFlags) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_UTF8|SQLITE_FUNC_INLINE|SQLITE_FUNC_CONSTANT|(mFlags), \
+   SQLITE_INT_TO_PTR(iArg), 0, noopFunc, 0, 0, 0, #zName, {0} }
+#define TEST_FUNC(zName, nArg, iArg, mFlags) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+         SQLITE_UTF8|SQLITE_FUNC_INTERNAL|SQLITE_FUNC_TEST| \
+         SQLITE_FUNC_INLINE|SQLITE_FUNC_CONSTANT|(mFlags), \
+   SQLITE_INT_TO_PTR(iArg), 0, noopFunc, 0, 0, 0, #zName, {0} }
+#define DFUNCTION(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_FUNC_SLOCHNG|SQLITE_UTF8, \
+   0, 0, xFunc, 0, 0, 0, #zName, {0} }
+#define PURE_DATE(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+         SQLITE_FUNC_SLOCHNG|SQLITE_UTF8|SQLITE_FUNC_CONSTANT, \
+   (void*)&sqlite3Config, 0, xFunc, 0, 0, 0, #zName, {0} }
+#define FUNCTION2(zName, nArg, iArg, bNC, xFunc, extraFlags) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_FUNC_CONSTANT|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL)|extraFlags,\
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, 0, #zName, {0} }
+#define STR_FUNCTION(zName, nArg, pArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_FUNC_SLOCHNG|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
+   pArg, 0, xFunc, 0, 0, 0, #zName, }
+#define LIKEFUNC(zName, nArg, arg, flags) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_FUNC_CONSTANT|SQLITE_UTF8|flags, \
+   (void *)arg, 0, likeFunc, 0, 0, 0, #zName, {0} }
+#define WAGGREGATE(zName, nArg, arg, nc, xStep, xFinal, xValue, xInverse, f) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_UTF8|(nc*SQLITE_FUNC_NEEDCOLL)|f, \
+   SQLITE_INT_TO_PTR(arg), 0, xStep,xFinal,xValue,xInverse,#zName, {0}}
+#define INTERNAL_FUNCTION(zName, nArg, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_FUNC_INTERNAL|SQLITE_UTF8|SQLITE_FUNC_CONSTANT, \
+   0, 0, xFunc, 0, 0, 0, #zName, {0} }
+
+
+/*
+** All current savepoints are stored in a linked list starting at
+** sqlite3.pSavepoint. The first element in the list is the most recently
+** opened savepoint. Savepoints are added to the list by the vdbe
+** OP_Savepoint instruction.
+*/
+struct Savepoint {
+  char *zName;                        /* Savepoint name (nul-terminated) */
+  i64 nDeferredCons;                  /* Number of deferred fk violations */
+  i64 nDeferredImmCons;               /* Number of deferred imm fk. */
+  Savepoint *pNext;                   /* Parent savepoint (if any) */
+};
+
+/*
+** The following are used as the second parameter to sqlite3Savepoint(),
+** and as the P1 argument to the OP_Savepoint instruction.
+*/
+#define SAVEPOINT_BEGIN      0
+#define SAVEPOINT_RELEASE    1
+#define SAVEPOINT_ROLLBACK   2
+
+
+/*
+** Each SQLite module (virtual table definition) is defined by an
+** instance of the following structure, stored in the sqlite3.aModule
+** hash table.
+*/
+struct Module {
+  const sqlite3_module *pModule;       /* Callback pointers */
+  const char *zName;                   /* Name passed to create_module() */
+  int nRefModule;                      /* Number of pointers to this object */
+  void *pAux;                          /* pAux passed to create_module() */
+  void (*xDestroy)(void *);            /* Module destructor function */
+  Table *pEpoTab;                      /* Eponymous table for this module */
+};
+
+/*
+** Information about each column of an SQL table is held in an instance
+** of the Column structure, in the Table.aCol[] array.
+**
+** Definitions:
+**
+**   "table column index"     This is the index of the column in the
+**                            Table.aCol[] array, and also the index of
+**                            the column in the original CREATE TABLE stmt.
+**
+**   "storage column index"   This is the index of the column in the
+**                            record BLOB generated by the OP_MakeRecord
+**                            opcode.  The storage column index is less than
+**                            or equal to the table column index.  It is
+**                            equal if and only if there are no VIRTUAL
+**                            columns to the left.
+**
+** Notes on zCnName:
+** The zCnName field stores the name of the column, the datatype of the
+** column, and the collating sequence for the column, in that order, all in
+** a single allocation.  Each string is 0x00 terminated.  The datatype
+** is only included if the COLFLAG_HASTYPE bit of colFlags is set and the
+** collating sequence name is only included if the COLFLAG_HASCOLL bit is
+** set.
+*/
+struct Column {
+  char *zCnName;        /* Name of this column */
+  unsigned notNull :4;  /* An OE_ code for handling a NOT NULL constraint */
+  unsigned eCType :4;   /* One of the standard types */
+  char affinity;        /* One of the SQLITE_AFF_... values */
+  u8 szEst;             /* Est size of value in this column. sizeof(INT)==1 */
+  u8 hName;             /* Column name hash for faster lookup */
+  u16 iDflt;            /* 1-based index of DEFAULT.  0 means "none" */
+  u16 colFlags;         /* Boolean properties.  See COLFLAG_ defines below */
+};
+
+/* Allowed values for Column.eCType.
+**
+** Values must match entries in the global constant arrays
+** sqlite3StdTypeLen[] and sqlite3StdType[].  Each value is one more
+** than the offset into these arrays for the corresponding name.
+** Adjust the SQLITE_N_STDTYPE value if adding or removing entries.
+*/
+#define COLTYPE_CUSTOM      0   /* Type appended to zName */
+#define COLTYPE_ANY         1
+#define COLTYPE_BLOB        2
+#define COLTYPE_INT         3
+#define COLTYPE_INTEGER     4
+#define COLTYPE_REAL        5
+#define COLTYPE_TEXT        6
+#define SQLITE_N_STDTYPE    6  /* Number of standard types */
+
+/* Allowed values for Column.colFlags.
+**
+** Constraints:
+**         TF_HasVirtual == COLFLAG_VIRTUAL
+**         TF_HasStored  == COLFLAG_STORED
+**         TF_HasHidden  == COLFLAG_HIDDEN
+*/
+#define COLFLAG_PRIMKEY   0x0001   /* Column is part of the primary key */
+#define COLFLAG_HIDDEN    0x0002   /* A hidden column in a virtual table */
+#define COLFLAG_HASTYPE   0x0004   /* Type name follows column name */
+#define COLFLAG_UNIQUE    0x0008   /* Column def contains "UNIQUE" or "PK" */
+#define COLFLAG_SORTERREF 0x0010   /* Use sorter-refs with this column */
+#define COLFLAG_VIRTUAL   0x0020   /* GENERATED ALWAYS AS ... VIRTUAL */
+#define COLFLAG_STORED    0x0040   /* GENERATED ALWAYS AS ... STORED */
+#define COLFLAG_NOTAVAIL  0x0080   /* STORED column not yet calculated */
+#define COLFLAG_BUSY      0x0100   /* Blocks recursion on GENERATED columns */
+#define COLFLAG_HASCOLL   0x0200   /* Has collating sequence name in zCnName */
+#define COLFLAG_NOEXPAND  0x0400   /* Omit this column when expanding "*" */
+#define COLFLAG_GENERATED 0x0060   /* Combo: _STORED, _VIRTUAL */
+#define COLFLAG_NOINSERT  0x0062   /* Combo: _HIDDEN, _STORED, _VIRTUAL */
+
+/*
+** A "Collating Sequence" is defined by an instance of the following
+** structure. Conceptually, a collating sequence consists of a name and
+** a comparison routine that defines the order of that sequence.
+**
+** If CollSeq.xCmp is NULL, it means that the
+** collating sequence is undefined.  Indices built on an undefined
+** collating sequence may not be read or written.
+*/
+struct CollSeq {
+  char *zName;          /* Name of the collating sequence, UTF-8 encoded */
+  u8 enc;               /* Text encoding handled by xCmp() */
+  void *pUser;          /* First argument to xCmp() */
+  int (*xCmp)(void*,int, const void*, int, const void*);
+  void (*xDel)(void*);  /* Destructor for pUser */
+};
+
+/*
+** A sort order can be either ASC or DESC.
+*/
+#define SQLITE_SO_ASC       0  /* Sort in ascending order */
+#define SQLITE_SO_DESC      1  /* Sort in ascending order */
+#define SQLITE_SO_UNDEFINED -1 /* No sort order specified */
+
+/*
+** Column affinity types.
+**
+** These used to have mnemonic name like 'i' for SQLITE_AFF_INTEGER and
+** 't' for SQLITE_AFF_TEXT.  But we can save a little space and improve
+** the speed a little by numbering the values consecutively.
+**
+** But rather than start with 0 or 1, we begin with 'A'.  That way,
+** when multiple affinity types are concatenated into a string and
+** used as the P4 operand, they will be more readable.
+**
+** Note also that the numeric types are grouped together so that testing
+** for a numeric type is a single comparison.  And the BLOB type is first.
+*/
+#define SQLITE_AFF_NONE     0x40  /* '@' */
+#define SQLITE_AFF_BLOB     0x41  /* 'A' */
+#define SQLITE_AFF_TEXT     0x42  /* 'B' */
+#define SQLITE_AFF_NUMERIC  0x43  /* 'C' */
+#define SQLITE_AFF_INTEGER  0x44  /* 'D' */
+#define SQLITE_AFF_REAL     0x45  /* 'E' */
+#define SQLITE_AFF_FLEXNUM  0x46  /* 'F' */
+
+#define sqlite3IsNumericAffinity(X)  ((X)>=SQLITE_AFF_NUMERIC)
+
+/*
+** The SQLITE_AFF_MASK values masks off the significant bits of an
+** affinity value.
+*/
+#define SQLITE_AFF_MASK     0x47
+
+/*
+** Additional bit values that can be ORed with an affinity without
+** changing the affinity.
+**
+** The SQLITE_NOTNULL flag is a combination of NULLEQ and JUMPIFNULL.
+** It causes an assert() to fire if either operand to a comparison
+** operator is NULL.  It is added to certain comparison operators to
+** prove that the operands are always NOT NULL.
+*/
+#define SQLITE_JUMPIFNULL   0x10  /* jumps if either operand is NULL */
+#define SQLITE_NULLEQ       0x80  /* NULL=NULL */
+#define SQLITE_NOTNULL      0x90  /* Assert that operands are never NULL */
+
+/*
+** An object of this type is created for each virtual table present in
+** the database schema.
+**
+** If the database schema is shared, then there is one instance of this
+** structure for each database connection (sqlite3*) that uses the shared
+** schema. This is because each database connection requires its own unique
+** instance of the sqlite3_vtab* handle used to access the virtual table
+** implementation. sqlite3_vtab* handles can not be shared between
+** database connections, even when the rest of the in-memory database
+** schema is shared, as the implementation often stores the database
+** connection handle passed to it via the xConnect() or xCreate() method
+** during initialization internally. This database connection handle may
+** then be used by the virtual table implementation to access real tables
+** within the database. So that they appear as part of the callers
+** transaction, these accesses need to be made via the same database
+** connection as that used to execute SQL operations on the virtual table.
+**
+** All VTable objects that correspond to a single table in a shared
+** database schema are initially stored in a linked-list pointed to by
+** the Table.pVTable member variable of the corresponding Table object.
+** When an sqlite3_prepare() operation is required to access the virtual
+** table, it searches the list for the VTable that corresponds to the
+** database connection doing the preparing so as to use the correct
+** sqlite3_vtab* handle in the compiled query.
+**
+** When an in-memory Table object is deleted (for example when the
+** schema is being reloaded for some reason), the VTable objects are not
+** deleted and the sqlite3_vtab* handles are not xDisconnect()ed
+** immediately. Instead, they are moved from the Table.pVTable list to
+** another linked list headed by the sqlite3.pDisconnect member of the
+** corresponding sqlite3 structure. They are then deleted/xDisconnected
+** next time a statement is prepared using said sqlite3*. This is done
+** to avoid deadlock issues involving multiple sqlite3.mutex mutexes.
+** Refer to comments above function sqlite3VtabUnlockList() for an
+** explanation as to why it is safe to add an entry to an sqlite3.pDisconnect
+** list without holding the corresponding sqlite3.mutex mutex.
+**
+** The memory for objects of this type is always allocated by
+** sqlite3DbMalloc(), using the connection handle stored in VTable.db as
+** the first argument.
+*/
+struct VTable {
+  sqlite3 *db;              /* Database connection associated with this table */
+  Module *pMod;             /* Pointer to module implementation */
+  sqlite3_vtab *pVtab;      /* Pointer to vtab instance */
+  int nRef;                 /* Number of pointers to this structure */
+  u8 bConstraint;           /* True if constraints are supported */
+  u8 bAllSchemas;           /* True if might use any attached schema */
+  u8 eVtabRisk;             /* Riskiness of allowing hacker access */
+  int iSavepoint;           /* Depth of the SAVEPOINT stack */
+  VTable *pNext;            /* Next in linked list (see above) */
+};
+
+/* Allowed values for VTable.eVtabRisk
+*/
+#define SQLITE_VTABRISK_Low          0
+#define SQLITE_VTABRISK_Normal       1
+#define SQLITE_VTABRISK_High         2
+
+/*
+** The schema for each SQL table, virtual table, and view is represented
+** in memory by an instance of the following structure.
+*/
+struct Table {
+  char *zName;         /* Name of the table or view */
+  Column *aCol;        /* Information about each column */
+  Index *pIndex;       /* List of SQL indexes on this table. */
+  char *zColAff;       /* String defining the affinity of each column */
+  ExprList *pCheck;    /* All CHECK constraints */
+                       /*   ... also used as column name list in a VIEW */
+  Pgno tnum;           /* Root BTree page for this table */
+  u32 nTabRef;         /* Number of pointers to this Table */
+  u32 tabFlags;        /* Mask of TF_* values */
+  i16 iPKey;           /* If not negative, use aCol[iPKey] as the rowid */
+  i16 nCol;            /* Number of columns in this table */
+  i16 nNVCol;          /* Number of columns that are not VIRTUAL */
+  LogEst nRowLogEst;   /* Estimated rows in table - from sqlite_stat1 table */
+  LogEst szTabRow;     /* Estimated size of each table row in bytes */
+#ifdef SQLITE_ENABLE_COSTMULT
+  LogEst costMult;     /* Cost multiplier for using this table */
+#endif
+  u8 keyConf;          /* What to do in case of uniqueness conflict on iPKey */
+  u8 eTabType;         /* 0: normal, 1: virtual, 2: view */
+  union {
+    struct {             /* Used by ordinary tables: */
+      int addColOffset;    /* Offset in CREATE TABLE stmt to add a new column */
+      FKey *pFKey;         /* Linked list of all foreign keys in this table */
+      ExprList *pDfltList; /* DEFAULT clauses on various columns.
+                           ** Or the AS clause for generated columns. */
+    } tab;
+    struct {             /* Used by views: */
+      Select *pSelect;     /* View definition */
+    } view;
+    struct {             /* Used by virtual tables only: */
+      int nArg;            /* Number of arguments to the module */
+      char **azArg;        /* 0: module 1: schema 2: vtab name 3...: args */
+      VTable *p;           /* List of VTable objects. */
+    } vtab;
+  } u;
+  Trigger *pTrigger;   /* List of triggers on this object */
+  Schema *pSchema;     /* Schema that contains this table */
+};
+
+/*
+** Allowed values for Table.tabFlags.
+**
+** TF_OOOHidden applies to tables or view that have hidden columns that are
+** followed by non-hidden columns.  Example:  "CREATE VIRTUAL TABLE x USING
+** vtab1(a HIDDEN, b);".  Since "b" is a non-hidden column but "a" is hidden,
+** the TF_OOOHidden attribute would apply in this case.  Such tables require
+** special handling during INSERT processing. The "OOO" means "Out Of Order".
+**
+** Constraints:
+**
+**         TF_HasVirtual == COLFLAG_VIRTUAL
+**         TF_HasStored  == COLFLAG_STORED
+**         TF_HasHidden  == COLFLAG_HIDDEN
+*/
+#define TF_Readonly       0x00000001 /* Read-only system table */
+#define TF_HasHidden      0x00000002 /* Has one or more hidden columns */
+#define TF_HasPrimaryKey  0x00000004 /* Table has a primary key */
+#define TF_Autoincrement  0x00000008 /* Integer primary key is autoincrement */
+#define TF_HasStat1       0x00000010 /* nRowLogEst set from sqlite_stat1 */
+#define TF_HasVirtual     0x00000020 /* Has one or more VIRTUAL columns */
+#define TF_HasStored      0x00000040 /* Has one or more STORED columns */
+#define TF_HasGenerated   0x00000060 /* Combo: HasVirtual + HasStored */
+#define TF_WithoutRowid   0x00000080 /* No rowid.  PRIMARY KEY is the key */
+#define TF_MaybeReanalyze 0x00000100 /* Maybe run ANALYZE on this table */
+#define TF_NoVisibleRowid 0x00000200 /* No user-visible "rowid" column */
+#define TF_OOOHidden      0x00000400 /* Out-of-Order hidden columns */
+#define TF_HasNotNull     0x00000800 /* Contains NOT NULL constraints */
+#define TF_Shadow         0x00001000 /* True for a shadow table */
+#define TF_HasStat4       0x00002000 /* STAT4 info available for this table */
+#define TF_Ephemeral      0x00004000 /* An ephemeral table */
+#define TF_Eponymous      0x00008000 /* An eponymous virtual table */
+#define TF_Strict         0x00010000 /* STRICT mode */
+
+/*
+** Allowed values for Table.eTabType
+*/
+#define TABTYP_NORM      0     /* Ordinary table */
+#define TABTYP_VTAB      1     /* Virtual table */
+#define TABTYP_VIEW      2     /* A view */
+
+#define IsView(X)           ((X)->eTabType==TABTYP_VIEW)
+#define IsOrdinaryTable(X)  ((X)->eTabType==TABTYP_NORM)
+
+/*
+** Test to see whether or not a table is a virtual table.  This is
+** done as a macro so that it will be optimized out when virtual
+** table support is omitted from the build.
+*/
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+#  define IsVirtual(X)      ((X)->eTabType==TABTYP_VTAB)
+#  define ExprIsVtab(X)  \
+   ((X)->op==TK_COLUMN && (X)->y.pTab->eTabType==TABTYP_VTAB)
+#else
+#  define IsVirtual(X)      0
+#  define ExprIsVtab(X)     0
+#endif
+
+/*
+** Macros to determine if a column is hidden.  IsOrdinaryHiddenColumn()
+** only works for non-virtual tables (ordinary tables and views) and is
+** always false unless SQLITE_ENABLE_HIDDEN_COLUMNS is defined.  The
+** IsHiddenColumn() macro is general purpose.
+*/
+#if defined(SQLITE_ENABLE_HIDDEN_COLUMNS)
+#  define IsHiddenColumn(X)         (((X)->colFlags & COLFLAG_HIDDEN)!=0)
+#  define IsOrdinaryHiddenColumn(X) (((X)->colFlags & COLFLAG_HIDDEN)!=0)
+#elif !defined(SQLITE_OMIT_VIRTUALTABLE)
+#  define IsHiddenColumn(X)         (((X)->colFlags & COLFLAG_HIDDEN)!=0)
+#  define IsOrdinaryHiddenColumn(X) 0
+#else
+#  define IsHiddenColumn(X)         0
+#  define IsOrdinaryHiddenColumn(X) 0
+#endif
+
+
+/* Does the table have a rowid */
+#define HasRowid(X)     (((X)->tabFlags & TF_WithoutRowid)==0)
+#define VisibleRowid(X) (((X)->tabFlags & TF_NoVisibleRowid)==0)
+
+/* Macro is true if the SQLITE_ALLOW_ROWID_IN_VIEW (mis-)feature is
+** available.  By default, this macro is false
+*/
+#ifndef SQLITE_ALLOW_ROWID_IN_VIEW
+# define ViewCanHaveRowid     0
+#else
+# define ViewCanHaveRowid     (sqlite3Config.mNoVisibleRowid==0)
+#endif
+
+/*
+** Each foreign key constraint is an instance of the following structure.
+**
+** A foreign key is associated with two tables.  The "from" table is
+** the table that contains the REFERENCES clause that creates the foreign
+** key.  The "to" table is the table that is named in the REFERENCES clause.
+** Consider this example:
+**
+**     CREATE TABLE ex1(
+**       a INTEGER PRIMARY KEY,
+**       b INTEGER CONSTRAINT fk1 REFERENCES ex2(x)
+**     );
+**
+** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".
+** Equivalent names:
+**
+**     from-table == child-table
+**       to-table == parent-table
+**
+** Each REFERENCES clause generates an instance of the following structure
+** which is attached to the from-table.  The to-table need not exist when
+** the from-table is created.  The existence of the to-table is not checked.
+**
+** The list of all parents for child Table X is held at X.pFKey.
+**
+** A list of all children for a table named Z (which might not even exist)
+** is held in Schema.fkeyHash with a hash key of Z.
+*/
+struct FKey {
+  Table *pFrom;     /* Table containing the REFERENCES clause (aka: Child) */
+  FKey *pNextFrom;  /* Next FKey with the same in pFrom. Next parent of pFrom */
+  char *zTo;        /* Name of table that the key points to (aka: Parent) */
+  FKey *pNextTo;    /* Next with the same zTo. Next child of zTo. */
+  FKey *pPrevTo;    /* Previous with the same zTo */
+  int nCol;         /* Number of columns in this key */
+  /* EV: R-30323-21917 */
+  u8 isDeferred;       /* True if constraint checking is deferred till COMMIT */
+  u8 aAction[2];        /* ON DELETE and ON UPDATE actions, respectively */
+  Trigger *apTrigger[2];/* Triggers for aAction[] actions */
+  struct sColMap {      /* Mapping of columns in pFrom to columns in zTo */
+    int iFrom;            /* Index of column in pFrom */
+    char *zCol;           /* Name of column in zTo.  If NULL use PRIMARY KEY */
+  } aCol[1];            /* One entry for each of nCol columns */
+};
+
+/*
+** SQLite supports many different ways to resolve a constraint
+** error.  ROLLBACK processing means that a constraint violation
+** causes the operation in process to fail and for the current transaction
+** to be rolled back.  ABORT processing means the operation in process
+** fails and any prior changes from that one operation are backed out,
+** but the transaction is not rolled back.  FAIL processing means that
+** the operation in progress stops and returns an error code.  But prior
+** changes due to the same operation are not backed out and no rollback
+** occurs.  IGNORE means that the particular row that caused the constraint
+** error is not inserted or updated.  Processing continues and no error
+** is returned.  REPLACE means that preexisting database rows that caused
+** a UNIQUE constraint violation are removed so that the new insert or
+** update can proceed.  Processing continues and no error is reported.
+** UPDATE applies to insert operations only and means that the insert
+** is omitted and the DO UPDATE clause of an upsert is run instead.
+**
+** RESTRICT, SETNULL, SETDFLT, and CASCADE actions apply only to foreign keys.
+** RESTRICT is the same as ABORT for IMMEDIATE foreign keys and the
+** same as ROLLBACK for DEFERRED keys.  SETNULL means that the foreign
+** key is set to NULL.  SETDFLT means that the foreign key is set
+** to its default value.  CASCADE means that a DELETE or UPDATE of the
+** referenced table row is propagated into the row that holds the
+** foreign key.
+**
+** The OE_Default value is a place holder that means to use whatever
+** conflict resolution algorithm is required from context.
+**
+** The following symbolic values are used to record which type
+** of conflict resolution action to take.
+*/
+#define OE_None     0   /* There is no constraint to check */
+#define OE_Rollback 1   /* Fail the operation and rollback the transaction */
+#define OE_Abort    2   /* Back out changes but do no rollback transaction */
+#define OE_Fail     3   /* Stop the operation but leave all prior changes */
+#define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
+#define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */
+#define OE_Update   6   /* Process as a DO UPDATE in an upsert */
+#define OE_Restrict 7   /* OE_Abort for IMMEDIATE, OE_Rollback for DEFERRED */
+#define OE_SetNull  8   /* Set the foreign key value to NULL */
+#define OE_SetDflt  9   /* Set the foreign key value to its default */
+#define OE_Cascade  10  /* Cascade the changes */
+#define OE_Default  11  /* Do whatever the default action is */
+
+
+/*
+** An instance of the following structure is passed as the first
+** argument to sqlite3VdbeKeyCompare and is used to control the
+** comparison of the two index keys.
+**
+** Note that aSortOrder[] and aColl[] have nField+1 slots.  There
+** are nField slots for the columns of an index then one extra slot
+** for the rowid at the end.
+*/
+struct KeyInfo {
+  u32 nRef;           /* Number of references to this KeyInfo object */
+  u8 enc;             /* Text encoding - one of the SQLITE_UTF* values */
+  u16 nKeyField;      /* Number of key columns in the index */
+  u16 nAllField;      /* Total columns, including key plus others */
+  sqlite3 *db;        /* The database connection */
+  u8 *aSortFlags;     /* Sort order for each column. */
+  CollSeq *aColl[1];  /* Collating sequence for each term of the key */
+};
+
+/*
+** Allowed bit values for entries in the KeyInfo.aSortFlags[] array.
+*/
+#define KEYINFO_ORDER_DESC    0x01    /* DESC sort order */
+#define KEYINFO_ORDER_BIGNULL 0x02    /* NULL is larger than any other value */
+
+/*
+** This object holds a record which has been parsed out into individual
+** fields, for the purposes of doing a comparison.
+**
+** A record is an object that contains one or more fields of data.
+** Records are used to store the content of a table row and to store
+** the key of an index.  A blob encoding of a record is created by
+** the OP_MakeRecord opcode of the VDBE and is disassembled by the
+** OP_Column opcode.
+**
+** An instance of this object serves as a "key" for doing a search on
+** an index b+tree. The goal of the search is to find the entry that
+** is closed to the key described by this object.  This object might hold
+** just a prefix of the key.  The number of fields is given by
+** pKeyInfo->nField.
+**
+** The r1 and r2 fields are the values to return if this key is less than
+** or greater than a key in the btree, respectively.  These are normally
+** -1 and +1 respectively, but might be inverted to +1 and -1 if the b-tree
+** is in DESC order.
+**
+** The key comparison functions actually return default_rc when they find
+** an equals comparison.  default_rc can be -1, 0, or +1.  If there are
+** multiple entries in the b-tree with the same key (when only looking
+** at the first pKeyInfo->nFields,) then default_rc can be set to -1 to
+** cause the search to find the last match, or +1 to cause the search to
+** find the first match.
+**
+** The key comparison functions will set eqSeen to true if they ever
+** get and equal results when comparing this structure to a b-tree record.
+** When default_rc!=0, the search might end up on the record immediately
+** before the first match or immediately after the last match.  The
+** eqSeen field will indicate whether or not an exact match exists in the
+** b-tree.
+*/
+struct UnpackedRecord {
+  KeyInfo *pKeyInfo;  /* Collation and sort-order information */
+  Mem *aMem;          /* Values */
+  union {
+    char *z;            /* Cache of aMem[0].z for vdbeRecordCompareString() */
+    i64 i;              /* Cache of aMem[0].u.i for vdbeRecordCompareInt() */
+  } u;
+  int n;              /* Cache of aMem[0].n used by vdbeRecordCompareString() */
+  u16 nField;         /* Number of entries in apMem[] */
+  i8 default_rc;      /* Comparison result if keys are equal */
+  u8 errCode;         /* Error detected by xRecordCompare (CORRUPT or NOMEM) */
+  i8 r1;              /* Value to return if (lhs < rhs) */
+  i8 r2;              /* Value to return if (lhs > rhs) */
+  u8 eqSeen;          /* True if an equality comparison has been seen */
+};
+
+
+/*
+** Each SQL index is represented in memory by an
+** instance of the following structure.
+**
+** The columns of the table that are to be indexed are described
+** by the aiColumn[] field of this structure.  For example, suppose
+** we have the following table and index:
+**
+**     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
+**     CREATE INDEX Ex2 ON Ex1(c3,c1);
+**
+** In the Table structure describing Ex1, nCol==3 because there are
+** three columns in the table.  In the Index structure describing
+** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
+** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the
+** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
+** The second column to be indexed (c1) has an index of 0 in
+** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
+**
+** The Index.onError field determines whether or not the indexed columns
+** must be unique and what to do if they are not.  When Index.onError=OE_None,
+** it means this is not a unique index.  Otherwise it is a unique index
+** and the value of Index.onError indicates which conflict resolution
+** algorithm to employ when an attempt is made to insert a non-unique
+** element.
+**
+** The colNotIdxed bitmask is used in combination with SrcItem.colUsed
+** for a fast test to see if an index can serve as a covering index.
+** colNotIdxed has a 1 bit for every column of the original table that
+** is *not* available in the index.  Thus the expression
+** "colUsed & colNotIdxed" will be non-zero if the index is not a
+** covering index.  The most significant bit of of colNotIdxed will always
+** be true (note-20221022-a).  If a column beyond the 63rd column of the
+** table is used, the "colUsed & colNotIdxed" test will always be non-zero
+** and we have to assume either that the index is not covering, or use
+** an alternative (slower) algorithm to determine whether or not
+** the index is covering.
+**
+** While parsing a CREATE TABLE or CREATE INDEX statement in order to
+** generate VDBE code (as opposed to parsing one read from an sqlite_schema
+** table as part of parsing an existing database schema), transient instances
+** of this structure may be created. In this case the Index.tnum variable is
+** used to store the address of a VDBE instruction, not a database page
+** number (it cannot - the database page is not allocated until the VDBE
+** program is executed). See convertToWithoutRowidTable() for details.
+*/
+struct Index {
+  char *zName;             /* Name of this index */
+  i16 *aiColumn;           /* Which columns are used by this index.  1st is 0 */
+  LogEst *aiRowLogEst;     /* From ANALYZE: Est. rows selected by each column */
+  Table *pTable;           /* The SQL table being indexed */
+  char *zColAff;           /* String defining the affinity of each column */
+  Index *pNext;            /* The next index associated with the same table */
+  Schema *pSchema;         /* Schema containing this index */
+  u8 *aSortOrder;          /* for each column: True==DESC, False==ASC */
+  const char **azColl;     /* Array of collation sequence names for index */
+  Expr *pPartIdxWhere;     /* WHERE clause for partial indices */
+  ExprList *aColExpr;      /* Column expressions */
+  Pgno tnum;               /* DB Page containing root of this index */
+  LogEst szIdxRow;         /* Estimated average row size in bytes */
+  u16 nKeyCol;             /* Number of columns forming the key */
+  u16 nColumn;             /* Number of columns stored in the index */
+  u8 onError;              /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
+  unsigned idxType:2;      /* 0:Normal 1:UNIQUE, 2:PRIMARY KEY, 3:IPK */
+  unsigned bUnordered:1;   /* Use this index for == or IN queries only */
+  unsigned uniqNotNull:1;  /* True if UNIQUE and NOT NULL for all columns */
+  unsigned isResized:1;    /* True if resizeIndexObject() has been called */
+  unsigned isCovering:1;   /* True if this is a covering index */
+  unsigned noSkipScan:1;   /* Do not try to use skip-scan if true */
+  unsigned hasStat1:1;     /* aiRowLogEst values come from sqlite_stat1 */
+  unsigned bLowQual:1;     /* sqlite_stat1 says this is a low-quality index */
+  unsigned bNoQuery:1;     /* Do not use this index to optimize queries */
+  unsigned bAscKeyBug:1;   /* True if the bba7b69f9849b5bf bug applies */
+  unsigned bIdxRowid:1;    /* One or more of the index keys is the ROWID */
+  unsigned bHasVCol:1;     /* Index references one or more VIRTUAL columns */
+  unsigned bHasExpr:1;     /* Index contains an expression, either a literal
+                           ** expression, or a reference to a VIRTUAL column */
+#ifdef SQLITE_ENABLE_STAT4
+  int nSample;             /* Number of elements in aSample[] */
+  int mxSample;            /* Number of slots allocated to aSample[] */
+  int nSampleCol;          /* Size of IndexSample.anEq[] and so on */
+  tRowcnt *aAvgEq;         /* Average nEq values for keys not in aSample */
+  IndexSample *aSample;    /* Samples of the left-most key */
+  tRowcnt *aiRowEst;       /* Non-logarithmic stat1 data for this index */
+  tRowcnt nRowEst0;        /* Non-logarithmic number of rows in the index */
+#endif
+  Bitmask colNotIdxed;     /* Unindexed columns in pTab */
+};
+
+/*
+** Allowed values for Index.idxType
+*/
+#define SQLITE_IDXTYPE_APPDEF      0   /* Created using CREATE INDEX */
+#define SQLITE_IDXTYPE_UNIQUE      1   /* Implements a UNIQUE constraint */
+#define SQLITE_IDXTYPE_PRIMARYKEY  2   /* Is the PRIMARY KEY for the table */
+#define SQLITE_IDXTYPE_IPK         3   /* INTEGER PRIMARY KEY index */
+
+/* Return true if index X is a PRIMARY KEY index */
+#define IsPrimaryKeyIndex(X)  ((X)->idxType==SQLITE_IDXTYPE_PRIMARYKEY)
+
+/* Return true if index X is a UNIQUE index */
+#define IsUniqueIndex(X)      ((X)->onError!=OE_None)
+
+/* The Index.aiColumn[] values are normally positive integer.  But
+** there are some negative values that have special meaning:
+*/
+#define XN_ROWID     (-1)     /* Indexed column is the rowid */
+#define XN_EXPR      (-2)     /* Indexed column is an expression */
+
+/*
+** Each sample stored in the sqlite_stat4 table is represented in memory
+** using a structure of this type.  See documentation at the top of the
+** analyze.c source file for additional information.
+*/
+struct IndexSample {
+  void *p;          /* Pointer to sampled record */
+  int n;            /* Size of record in bytes */
+  tRowcnt *anEq;    /* Est. number of rows where the key equals this sample */
+  tRowcnt *anLt;    /* Est. number of rows where key is less than this sample */
+  tRowcnt *anDLt;   /* Est. number of distinct keys less than this sample */
+};
+
+/*
+** Possible values to use within the flags argument to sqlite3GetToken().
+*/
+#define SQLITE_TOKEN_QUOTED    0x1 /* Token is a quoted identifier. */
+#define SQLITE_TOKEN_KEYWORD   0x2 /* Token is a keyword. */
+
+/*
+** Each token coming out of the lexer is an instance of
+** this structure.  Tokens are also used as part of an expression.
+**
+** The memory that "z" points to is owned by other objects.  Take care
+** that the owner of the "z" string does not deallocate the string before
+** the Token goes out of scope!  Very often, the "z" points to some place
+** in the middle of the Parse.zSql text.  But it might also point to a
+** static string.
+*/
+struct Token {
+  const char *z;     /* Text of the token.  Not NULL-terminated! */
+  unsigned int n;    /* Number of characters in this token */
+};
+
+/*
+** An instance of this structure contains information needed to generate
+** code for a SELECT that contains aggregate functions.
+**
+** If Expr.op==TK_AGG_COLUMN or TK_AGG_FUNCTION then Expr.pAggInfo is a
+** pointer to this structure.  The Expr.iAgg field is the index in
+** AggInfo.aCol[] or AggInfo.aFunc[] of information needed to generate
+** code for that node.
+**
+** AggInfo.pGroupBy and AggInfo.aFunc.pExpr point to fields within the
+** original Select structure that describes the SELECT statement.  These
+** fields do not need to be freed when deallocating the AggInfo structure.
+*/
+struct AggInfo {
+  u8 directMode;          /* Direct rendering mode means take data directly
+                          ** from source tables rather than from accumulators */
+  u8 useSortingIdx;       /* In direct mode, reference the sorting index rather
+                          ** than the source table */
+  u16 nSortingColumn;     /* Number of columns in the sorting index */
+  int sortingIdx;         /* Cursor number of the sorting index */
+  int sortingIdxPTab;     /* Cursor number of pseudo-table */
+  int iFirstReg;          /* First register in range for aCol[] and aFunc[] */
+  ExprList *pGroupBy;     /* The group by clause */
+  struct AggInfo_col {    /* For each column used in source tables */
+    Table *pTab;             /* Source table */
+    Expr *pCExpr;            /* The original expression */
+    int iTable;              /* Cursor number of the source table */
+    i16 iColumn;             /* Column number within the source table */
+    i16 iSorterColumn;       /* Column number in the sorting index */
+  } *aCol;
+  int nColumn;            /* Number of used entries in aCol[] */
+  int nAccumulator;       /* Number of columns that show through to the output.
+                          ** Additional columns are used only as parameters to
+                          ** aggregate functions */
+  struct AggInfo_func {   /* For each aggregate function */
+    Expr *pFExpr;            /* Expression encoding the function */
+    FuncDef *pFunc;          /* The aggregate function implementation */
+    int iDistinct;           /* Ephemeral table used to enforce DISTINCT */
+    int iDistAddr;           /* Address of OP_OpenEphemeral */
+    int iOBTab;              /* Ephemeral table to implement ORDER BY */
+    u8 bOBPayload;           /* iOBTab has payload columns separate from key */
+    u8 bOBUnique;            /* Enforce uniqueness on iOBTab keys */
+    u8 bUseSubtype;          /* Transfer subtype info through sorter */
+  } *aFunc;
+  int nFunc;              /* Number of entries in aFunc[] */
+  u32 selId;              /* Select to which this AggInfo belongs */
+#ifdef SQLITE_DEBUG
+  Select *pSelect;        /* SELECT statement that this AggInfo supports */
+#endif
+};
+
+/*
+** Macros to compute aCol[] and aFunc[] register numbers.
+**
+** These macros should not be used prior to the call to
+** assignAggregateRegisters() that computes the value of pAggInfo->iFirstReg.
+** The assert()s that are part of this macro verify that constraint.
+*/
+#ifndef NDEBUG
+#define AggInfoColumnReg(A,I)  (assert((A)->iFirstReg),(A)->iFirstReg+(I))
+#define AggInfoFuncReg(A,I)    \
+                      (assert((A)->iFirstReg),(A)->iFirstReg+(A)->nColumn+(I))
+#else
+#define AggInfoColumnReg(A,I)  ((A)->iFirstReg+(I))
+#define AggInfoFuncReg(A,I)    \
+                      ((A)->iFirstReg+(A)->nColumn+(I))
+#endif
+
+/*
+** The datatype ynVar is a signed integer, either 16-bit or 32-bit.
+** Usually it is 16-bits.  But if SQLITE_MAX_VARIABLE_NUMBER is greater
+** than 32767 we have to make it 32-bit.  16-bit is preferred because
+** it uses less memory in the Expr object, which is a big memory user
+** in systems with lots of prepared statements.  And few applications
+** need more than about 10 or 20 variables.  But some extreme users want
+** to have prepared statements with over 32766 variables, and for them
+** the option is available (at compile-time).
+*/
+#if SQLITE_MAX_VARIABLE_NUMBER<32767
+typedef i16 ynVar;
+#else
+typedef int ynVar;
+#endif
+
+/*
+** Each node of an expression in the parse tree is an instance
+** of this structure.
+**
+** Expr.op is the opcode. The integer parser token codes are reused
+** as opcodes here. For example, the parser defines TK_GE to be an integer
+** code representing the ">=" operator. This same integer code is reused
+** to represent the greater-than-or-equal-to operator in the expression
+** tree.
+**
+** If the expression is an SQL literal (TK_INTEGER, TK_FLOAT, TK_BLOB,
+** or TK_STRING), then Expr.u.zToken contains the text of the SQL literal. If
+** the expression is a variable (TK_VARIABLE), then Expr.u.zToken contains the
+** variable name. Finally, if the expression is an SQL function (TK_FUNCTION),
+** then Expr.u.zToken contains the name of the function.
+**
+** Expr.pRight and Expr.pLeft are the left and right subexpressions of a
+** binary operator. Either or both may be NULL.
+**
+** Expr.x.pList is a list of arguments if the expression is an SQL function,
+** a CASE expression or an IN expression of the form "<lhs> IN (<y>, <z>...)".
+** Expr.x.pSelect is used if the expression is a sub-select or an expression of
+** the form "<lhs> IN (SELECT ...)". If the EP_xIsSelect bit is set in the
+** Expr.flags mask, then Expr.x.pSelect is valid. Otherwise, Expr.x.pList is
+** valid.
+**
+** An expression of the form ID or ID.ID refers to a column in a table.
+** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
+** the integer cursor number of a VDBE cursor pointing to that table and
+** Expr.iColumn is the column number for the specific column.  If the
+** expression is used as a result in an aggregate SELECT, then the
+** value is also stored in the Expr.iAgg column in the aggregate so that
+** it can be accessed after all aggregates are computed.
+**
+** If the expression is an unbound variable marker (a question mark
+** character '?' in the original SQL) then the Expr.iTable holds the index
+** number for that variable.
+**
+** If the expression is a subquery then Expr.iColumn holds an integer
+** register number containing the result of the subquery.  If the
+** subquery gives a constant result, then iTable is -1.  If the subquery
+** gives a different answer at different times during statement processing
+** then iTable is the address of a subroutine that computes the subquery.
+**
+** If the Expr is of type OP_Column, and the table it is selecting from
+** is a disk table or the "old.*" pseudo-table, then pTab points to the
+** corresponding table definition.
+**
+** ALLOCATION NOTES:
+**
+** Expr objects can use a lot of memory space in database schema.  To
+** help reduce memory requirements, sometimes an Expr object will be
+** truncated.  And to reduce the number of memory allocations, sometimes
+** two or more Expr objects will be stored in a single memory allocation,
+** together with Expr.u.zToken strings.
+**
+** If the EP_Reduced and EP_TokenOnly flags are set when
+** an Expr object is truncated.  When EP_Reduced is set, then all
+** the child Expr objects in the Expr.pLeft and Expr.pRight subtrees
+** are contained within the same memory allocation.  Note, however, that
+** the subtrees in Expr.x.pList or Expr.x.pSelect are always separately
+** allocated, regardless of whether or not EP_Reduced is set.
+*/
+struct Expr {
+  u8 op;                 /* Operation performed by this node */
+  char affExpr;          /* affinity, or RAISE type */
+  u8 op2;                /* TK_REGISTER/TK_TRUTH: original value of Expr.op
+                         ** TK_COLUMN: the value of p5 for OP_Column
+                         ** TK_AGG_FUNCTION: nesting depth
+                         ** TK_FUNCTION: NC_SelfRef flag if needs OP_PureFunc */
+#ifdef SQLITE_DEBUG
+  u8 vvaFlags;           /* Verification flags. */
+#endif
+  u32 flags;             /* Various flags.  EP_* See below */
+  union {
+    char *zToken;          /* Token value. Zero terminated and dequoted */
+    int iValue;            /* Non-negative integer value if EP_IntValue */
+  } u;
+
+  /* If the EP_TokenOnly flag is set in the Expr.flags mask, then no
+  ** space is allocated for the fields below this point. An attempt to
+  ** access them will result in a segfault or malfunction.
+  *********************************************************************/
+
+  Expr *pLeft;           /* Left subnode */
+  Expr *pRight;          /* Right subnode */
+  union {
+    ExprList *pList;     /* op = IN, EXISTS, SELECT, CASE, FUNCTION, BETWEEN */
+    Select *pSelect;     /* EP_xIsSelect and op = IN, EXISTS, SELECT */
+  } x;
+
+  /* If the EP_Reduced flag is set in the Expr.flags mask, then no
+  ** space is allocated for the fields below this point. An attempt to
+  ** access them will result in a segfault or malfunction.
+  *********************************************************************/
+
+#if SQLITE_MAX_EXPR_DEPTH>0
+  int nHeight;           /* Height of the tree headed by this node */
+#endif
+  int iTable;            /* TK_COLUMN: cursor number of table holding column
+                         ** TK_REGISTER: register number
+                         ** TK_TRIGGER: 1 -> new, 0 -> old
+                         ** EP_Unlikely:  134217728 times likelihood
+                         ** TK_IN: ephemeral table holding RHS
+                         ** TK_SELECT_COLUMN: Number of columns on the LHS
+                         ** TK_SELECT: 1st register of result vector */
+  ynVar iColumn;         /* TK_COLUMN: column index.  -1 for rowid.
+                         ** TK_VARIABLE: variable number (always >= 1).
+                         ** TK_SELECT_COLUMN: column of the result vector */
+  i16 iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
+  union {
+    int iJoin;             /* If EP_OuterON or EP_InnerON, the right table */
+    int iOfst;             /* else: start of token from start of statement */
+  } w;
+  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
+  union {
+    Table *pTab;           /* TK_COLUMN: Table containing column. Can be NULL
+                           ** for a column of an index on an expression */
+    Window *pWin;          /* EP_WinFunc: Window/Filter defn for a function */
+    struct {               /* TK_IN, TK_SELECT, and TK_EXISTS */
+      int iAddr;             /* Subroutine entry address */
+      int regReturn;         /* Register used to hold return address */
+    } sub;
+  } y;
+};
+
+/* The following are the meanings of bits in the Expr.flags field.
+** Value restrictions:
+**
+**          EP_Agg == NC_HasAgg == SF_HasAgg
+**          EP_Win == NC_HasWin
+*/
+#define EP_OuterON    0x000001 /* Originates in ON/USING clause of outer join */
+#define EP_InnerON    0x000002 /* Originates in ON/USING of an inner join */
+#define EP_Distinct   0x000004 /* Aggregate function with DISTINCT keyword */
+#define EP_HasFunc    0x000008 /* Contains one or more functions of any kind */
+#define EP_Agg        0x000010 /* Contains one or more aggregate functions */
+#define EP_FixedCol   0x000020 /* TK_Column with a known fixed value */
+#define EP_VarSelect  0x000040 /* pSelect is correlated, not constant */
+#define EP_DblQuoted  0x000080 /* token.z was originally in "..." */
+#define EP_InfixFunc  0x000100 /* True for an infix function: LIKE, GLOB, etc */
+#define EP_Collate    0x000200 /* Tree contains a TK_COLLATE operator */
+#define EP_Commuted   0x000400 /* Comparison operator has been commuted */
+#define EP_IntValue   0x000800 /* Integer value contained in u.iValue */
+#define EP_xIsSelect  0x001000 /* x.pSelect is valid (otherwise x.pList is) */
+#define EP_Skip       0x002000 /* Operator does not contribute to affinity */
+#define EP_Reduced    0x004000 /* Expr struct EXPR_REDUCEDSIZE bytes only */
+#define EP_Win        0x008000 /* Contains window functions */
+#define EP_TokenOnly  0x010000 /* Expr struct EXPR_TOKENONLYSIZE bytes only */
+#define EP_FullSize   0x020000 /* Expr structure must remain full sized */
+#define EP_IfNullRow  0x040000 /* The TK_IF_NULL_ROW opcode */
+#define EP_Unlikely   0x080000 /* unlikely() or likelihood() function */
+#define EP_ConstFunc  0x100000 /* A SQLITE_FUNC_CONSTANT or _SLOCHNG function */
+#define EP_CanBeNull  0x200000 /* Can be null despite NOT NULL constraint */
+#define EP_Subquery   0x400000 /* Tree contains a TK_SELECT operator */
+#define EP_Leaf       0x800000 /* Expr.pLeft, .pRight, .u.pSelect all NULL */
+#define EP_WinFunc   0x1000000 /* TK_FUNCTION with Expr.y.pWin set */
+#define EP_Subrtn    0x2000000 /* Uses Expr.y.sub. TK_IN, _SELECT, or _EXISTS */
+#define EP_Quoted    0x4000000 /* TK_ID was originally quoted */
+#define EP_Static    0x8000000 /* Held in memory not obtained from malloc() */
+#define EP_IsTrue   0x10000000 /* Always has boolean value of TRUE */
+#define EP_IsFalse  0x20000000 /* Always has boolean value of FALSE */
+#define EP_FromDDL  0x40000000 /* Originates from sqlite_schema */
+#define EP_SubtArg  0x80000000 /* Is argument to SQLITE_SUBTYPE function */
+
+/* The EP_Propagate mask is a set of properties that automatically propagate
+** upwards into parent nodes.
+*/
+#define EP_Propagate (EP_Collate|EP_Subquery|EP_HasFunc)
+
+/* Macros can be used to test, set, or clear bits in the
+** Expr.flags field.
+*/
+#define ExprHasProperty(E,P)     (((E)->flags&(P))!=0)
+#define ExprHasAllProperty(E,P)  (((E)->flags&(P))==(P))
+#define ExprSetProperty(E,P)     (E)->flags|=(P)
+#define ExprClearProperty(E,P)   (E)->flags&=~(P)
+#define ExprAlwaysTrue(E)   (((E)->flags&(EP_OuterON|EP_IsTrue))==EP_IsTrue)
+#define ExprAlwaysFalse(E)  (((E)->flags&(EP_OuterON|EP_IsFalse))==EP_IsFalse)
+#define ExprIsFullSize(E)   (((E)->flags&(EP_Reduced|EP_TokenOnly))==0)
+
+/* Macros used to ensure that the correct members of unions are accessed
+** in Expr.
+*/
+#define ExprUseUToken(E)    (((E)->flags&EP_IntValue)==0)
+#define ExprUseUValue(E)    (((E)->flags&EP_IntValue)!=0)
+#define ExprUseWOfst(E)     (((E)->flags&(EP_InnerON|EP_OuterON))==0)
+#define ExprUseWJoin(E)     (((E)->flags&(EP_InnerON|EP_OuterON))!=0)
+#define ExprUseXList(E)     (((E)->flags&EP_xIsSelect)==0)
+#define ExprUseXSelect(E)   (((E)->flags&EP_xIsSelect)!=0)
+#define ExprUseYTab(E)      (((E)->flags&(EP_WinFunc|EP_Subrtn))==0)
+#define ExprUseYWin(E)      (((E)->flags&EP_WinFunc)!=0)
+#define ExprUseYSub(E)      (((E)->flags&EP_Subrtn)!=0)
+
+/* Flags for use with Expr.vvaFlags
+*/
+#define EP_NoReduce   0x01  /* Cannot EXPRDUP_REDUCE this Expr */
+#define EP_Immutable  0x02  /* Do not change this Expr node */
+
+/* The ExprSetVVAProperty() macro is used for Verification, Validation,
+** and Accreditation only.  It works like ExprSetProperty() during VVA
+** processes but is a no-op for delivery.
+*/
+#ifdef SQLITE_DEBUG
+# define ExprSetVVAProperty(E,P)   (E)->vvaFlags|=(P)
+# define ExprHasVVAProperty(E,P)   (((E)->vvaFlags&(P))!=0)
+# define ExprClearVVAProperties(E) (E)->vvaFlags = 0
+#else
+# define ExprSetVVAProperty(E,P)
+# define ExprHasVVAProperty(E,P)   0
+# define ExprClearVVAProperties(E)
+#endif
+
+/*
+** Macros to determine the number of bytes required by a normal Expr
+** struct, an Expr struct with the EP_Reduced flag set in Expr.flags
+** and an Expr struct with the EP_TokenOnly flag set.
+*/
+#define EXPR_FULLSIZE           sizeof(Expr)           /* Full size */
+#define EXPR_REDUCEDSIZE        offsetof(Expr,iTable)  /* Common features */
+#define EXPR_TOKENONLYSIZE      offsetof(Expr,pLeft)   /* Fewer features */
+
+/*
+** Flags passed to the sqlite3ExprDup() function. See the header comment
+** above sqlite3ExprDup() for details.
+*/
+#define EXPRDUP_REDUCE         0x0001  /* Used reduced-size Expr nodes */
+
+/*
+** True if the expression passed as an argument was a function with
+** an OVER() clause (a window function).
+*/
+#ifdef SQLITE_OMIT_WINDOWFUNC
+# define IsWindowFunc(p) 0
+#else
+# define IsWindowFunc(p) ( \
+    ExprHasProperty((p), EP_WinFunc) && p->y.pWin->eFrmType!=TK_FILTER \
+ )
+#endif
+
+/*
+** A list of expressions.  Each expression may optionally have a
+** name.  An expr/name combination can be used in several ways, such
+** as the list of "expr AS ID" fields following a "SELECT" or in the
+** list of "ID = expr" items in an UPDATE.  A list of expressions can
+** also be used as the argument to a function, in which case the a.zName
+** field is not used.
+**
+** In order to try to keep memory usage down, the Expr.a.zEName field
+** is used for multiple purposes:
+**
+**     eEName          Usage
+**    ----------       -------------------------
+**    ENAME_NAME       (1) the AS of result set column
+**                     (2) COLUMN= of an UPDATE
+**
+**    ENAME_TAB        DB.TABLE.NAME used to resolve names
+**                     of subqueries
+**
+**    ENAME_SPAN       Text of the original result set
+**                     expression.
+*/
+struct ExprList {
+  int nExpr;             /* Number of expressions on the list */
+  int nAlloc;            /* Number of a[] slots allocated */
+  struct ExprList_item { /* For each expression in the list */
+    Expr *pExpr;            /* The parse tree for this expression */
+    char *zEName;           /* Token associated with this expression */
+    struct {
+      u8 sortFlags;           /* Mask of KEYINFO_ORDER_* flags */
+      unsigned eEName :2;     /* Meaning of zEName */
+      unsigned done :1;       /* Indicates when processing is finished */
+      unsigned reusable :1;   /* Constant expression is reusable */
+      unsigned bSorterRef :1; /* Defer evaluation until after sorting */
+      unsigned bNulls :1;     /* True if explicit "NULLS FIRST/LAST" */
+      unsigned bUsed :1;      /* This column used in a SF_NestedFrom subquery */
+      unsigned bUsingTerm:1;  /* Term from the USING clause of a NestedFrom */
+      unsigned bNoExpand: 1;  /* Term is an auxiliary in NestedFrom and should
+                              ** not be expanded by "*" in parent queries */
+    } fg;
+    union {
+      struct {             /* Used by any ExprList other than Parse.pConsExpr */
+        u16 iOrderByCol;      /* For ORDER BY, column number in result set */
+        u16 iAlias;           /* Index into Parse.aAlias[] for zName */
+      } x;
+      int iConstExprReg;   /* Register in which Expr value is cached. Used only
+                           ** by Parse.pConstExpr */
+    } u;
+  } a[1];                  /* One slot for each expression in the list */
+};
+
+/*
+** Allowed values for Expr.a.eEName
+*/
+#define ENAME_NAME  0       /* The AS clause of a result set */
+#define ENAME_SPAN  1       /* Complete text of the result set expression */
+#define ENAME_TAB   2       /* "DB.TABLE.NAME" for the result set */
+#define ENAME_ROWID 3       /* "DB.TABLE._rowid_" for * expansion of rowid */
+
+/*
+** An instance of this structure can hold a simple list of identifiers,
+** such as the list "a,b,c" in the following statements:
+**
+**      INSERT INTO t(a,b,c) VALUES ...;
+**      CREATE INDEX idx ON t(a,b,c);
+**      CREATE TRIGGER trig BEFORE UPDATE ON t(a,b,c) ...;
+**
+** The IdList.a.idx field is used when the IdList represents the list of
+** column names after a table name in an INSERT statement.  In the statement
+**
+**     INSERT INTO t(a,b,c) ...
+**
+** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
+*/
+struct IdList {
+  int nId;         /* Number of identifiers on the list */
+  struct IdList_item {
+    char *zName;      /* Name of the identifier */
+  } a[1];
+};
+
+/*
+** Allowed values for IdList.eType, which determines which value of the a.u4
+** is valid.
+*/
+#define EU4_NONE   0   /* Does not use IdList.a.u4 */
+#define EU4_IDX    1   /* Uses IdList.a.u4.idx */
+#define EU4_EXPR   2   /* Uses IdList.a.u4.pExpr -- NOT CURRENTLY USED */
+
+/*
+** Details of the implementation of a subquery.
+*/
+struct Subquery {
+  Select *pSelect;  /* A SELECT statement used in place of a table name */
+  int addrFillSub;  /* Address of subroutine to initialize a subquery */
+  int regReturn;    /* Register holding return address of addrFillSub */
+  int regResult;    /* Registers holding results of a co-routine */
+};
+
+/*
+** The SrcItem object represents a single term in the FROM clause of a query.
+** The SrcList object is mostly an array of SrcItems.
+**
+** The jointype starts out showing the join type between the current table
+** and the next table on the list.  The parser builds the list this way.
+** But sqlite3SrcListShiftJoinType() later shifts the jointypes so that each
+** jointype expresses the join between the table and the previous table.
+**
+** In the colUsed field, the high-order bit (bit 63) is set if the table
+** contains more than 63 columns and the 64-th or later column is used.
+**
+** Aggressive use of "union" helps keep the size of the object small.  This
+** has been shown to boost performance, in addition to saving memory.
+** Access to union elements is gated by the following rules which should
+** always be checked, either by an if-statement or by an assert().
+**
+**    Field              Only access if this is true
+**    ---------------    -----------------------------------
+**    u1.zIndexedBy      fg.isIndexedBy
+**    u1.pFuncArg        fg.isTabFunc
+**    u1.nRow            !fg.isTabFunc  && !fg.isIndexedBy
+**
+**    u2.pIBIndex        fg.isIndexedBy
+**    u2.pCteUse         fg.isCte
+**
+**    u3.pOn             !fg.isUsing
+**    u3.pUsing          fg.isUsing
+**
+**    u4.zDatabase       !fg.fixedSchema && !fg.isSubquery
+**    u4.pSchema         fg.fixedSchema
+**    u4.pSubq           fg.isSubquery
+**
+** See also the sqlite3SrcListDelete() routine for assert() statements that
+** check invariants on the fields of this object, especially the flags
+** inside the fg struct.
+*/
+struct SrcItem {
+  char *zName;      /* Name of the table */
+  char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
+  Table *pSTab;     /* Table object for zName. Mnemonic: Srcitem-TABle */
+  struct {
+    u8 jointype;      /* Type of join between this table and the previous */
+    unsigned notIndexed :1;    /* True if there is a NOT INDEXED clause */
+    unsigned isIndexedBy :1;   /* True if there is an INDEXED BY clause */
+    unsigned isSubquery :1;    /* True if this term is a subquery */
+    unsigned isTabFunc :1;     /* True if table-valued-function syntax */
+    unsigned isCorrelated :1;  /* True if sub-query is correlated */
+    unsigned isMaterialized:1; /* This is a materialized view */
+    unsigned viaCoroutine :1;  /* Implemented as a co-routine */
+    unsigned isRecursive :1;   /* True for recursive reference in WITH */
+    unsigned fromDDL :1;       /* Comes from sqlite_schema */
+    unsigned isCte :1;         /* This is a CTE */
+    unsigned notCte :1;        /* This item may not match a CTE */
+    unsigned isUsing :1;       /* u3.pUsing is valid */
+    unsigned isOn :1;          /* u3.pOn was once valid and non-NULL */
+    unsigned isSynthUsing :1;  /* u3.pUsing is synthesized from NATURAL */
+    unsigned isNestedFrom :1;  /* pSelect is a SF_NestedFrom subquery */
+    unsigned rowidUsed :1;     /* The ROWID of this table is referenced */
+    unsigned fixedSchema :1;   /* Uses u4.pSchema, not u4.zDatabase */
+    unsigned hadSchema :1;     /* Had u4.zDatabase before u4.pSchema */
+  } fg;
+  int iCursor;      /* The VDBE cursor number used to access this table */
+  Bitmask colUsed;  /* Bit N set if column N used. Details above for N>62 */
+  union {
+    char *zIndexedBy;    /* Identifier from "INDEXED BY <zIndex>" clause */
+    ExprList *pFuncArg;  /* Arguments to table-valued-function */
+    u32 nRow;            /* Number of rows in a VALUES clause */
+  } u1;
+  union {
+    Index *pIBIndex;  /* Index structure corresponding to u1.zIndexedBy */
+    CteUse *pCteUse;  /* CTE Usage info when fg.isCte is true */
+  } u2;
+  union {
+    Expr *pOn;        /* fg.isUsing==0 =>  The ON clause of a join */
+    IdList *pUsing;   /* fg.isUsing==1 =>  The USING clause of a join */
+  } u3;
+  union {
+    Schema *pSchema;  /* Schema to which this item is fixed */
+    char *zDatabase;  /* Name of database holding this table */
+    Subquery *pSubq;  /* Description of a subquery */
+  } u4;
+};
+
+/*
+** The OnOrUsing object represents either an ON clause or a USING clause.
+** It can never be both at the same time, but it can be neither.
+*/
+struct OnOrUsing {
+  Expr *pOn;         /* The ON clause of a join */
+  IdList *pUsing;    /* The USING clause of a join */
+};
+
+/*
+** This object represents one or more tables that are the source of
+** content for an SQL statement.  For example, a single SrcList object
+** is used to hold the FROM clause of a SELECT statement.  SrcList also
+** represents the target tables for DELETE, INSERT, and UPDATE statements.
+**
+*/
+struct SrcList {
+  int nSrc;        /* Number of tables or subqueries in the FROM clause */
+  u32 nAlloc;      /* Number of entries allocated in a[] below */
+  SrcItem a[1];    /* One entry for each identifier on the list */
+};
+
+/*
+** Permitted values of the SrcList.a.jointype field
+*/
+#define JT_INNER     0x01    /* Any kind of inner or cross join */
+#define JT_CROSS     0x02    /* Explicit use of the CROSS keyword */
+#define JT_NATURAL   0x04    /* True for a "natural" join */
+#define JT_LEFT      0x08    /* Left outer join */
+#define JT_RIGHT     0x10    /* Right outer join */
+#define JT_OUTER     0x20    /* The "OUTER" keyword is present */
+#define JT_LTORJ     0x40    /* One of the LEFT operands of a RIGHT JOIN
+                             ** Mnemonic: Left Table Of Right Join */
+#define JT_ERROR     0x80    /* unknown or unsupported join type */
+
+/*
+** Flags appropriate for the wctrlFlags parameter of sqlite3WhereBegin()
+** and the WhereInfo.wctrlFlags member.
+**
+** Value constraints (enforced via assert()):
+**     WHERE_USE_LIMIT  == SF_FixedLimit
+*/
+#define WHERE_ORDERBY_NORMAL   0x0000 /* No-op */
+#define WHERE_ORDERBY_MIN      0x0001 /* ORDER BY processing for min() func */
+#define WHERE_ORDERBY_MAX      0x0002 /* ORDER BY processing for max() func */
+#define WHERE_ONEPASS_DESIRED  0x0004 /* Want to do one-pass UPDATE/DELETE */
+#define WHERE_ONEPASS_MULTIROW 0x0008 /* ONEPASS is ok with multiple rows */
+#define WHERE_DUPLICATES_OK    0x0010 /* Ok to return a row more than once */
+#define WHERE_OR_SUBCLAUSE     0x0020 /* Processing a sub-WHERE as part of
+                                      ** the OR optimization  */
+#define WHERE_GROUPBY          0x0040 /* pOrderBy is really a GROUP BY */
+#define WHERE_DISTINCTBY       0x0080 /* pOrderby is really a DISTINCT clause */
+#define WHERE_WANT_DISTINCT    0x0100 /* All output needs to be distinct */
+#define WHERE_SORTBYGROUP      0x0200 /* Support sqlite3WhereIsSorted() */
+#define WHERE_AGG_DISTINCT     0x0400 /* Query is "SELECT agg(DISTINCT ...)" */
+#define WHERE_ORDERBY_LIMIT    0x0800 /* ORDERBY+LIMIT on the inner loop */
+#define WHERE_RIGHT_JOIN       0x1000 /* Processing a RIGHT JOIN */
+#define WHERE_KEEP_ALL_JOINS   0x2000 /* Do not do the omit-noop-join opt */
+#define WHERE_USE_LIMIT        0x4000 /* Use the LIMIT in cost estimates */
+                        /*     0x8000    not currently used */
+
+/* Allowed return values from sqlite3WhereIsDistinct()
+*/
+#define WHERE_DISTINCT_NOOP      0  /* DISTINCT keyword not used */
+#define WHERE_DISTINCT_UNIQUE    1  /* No duplicates */
+#define WHERE_DISTINCT_ORDERED   2  /* All duplicates are adjacent */
+#define WHERE_DISTINCT_UNORDERED 3  /* Duplicates are scattered */
+
+/*
+** A NameContext defines a context in which to resolve table and column
+** names.  The context consists of a list of tables (the pSrcList) field and
+** a list of named expression (pEList).  The named expression list may
+** be NULL.  The pSrc corresponds to the FROM clause of a SELECT or
+** to the table being operated on by INSERT, UPDATE, or DELETE.  The
+** pEList corresponds to the result set of a SELECT and is NULL for
+** other statements.
+**
+** NameContexts can be nested.  When resolving names, the inner-most
+** context is searched first.  If no match is found, the next outer
+** context is checked.  If there is still no match, the next context
+** is checked.  This process continues until either a match is found
+** or all contexts are check.  When a match is found, the nRef member of
+** the context containing the match is incremented.
+**
+** Each subquery gets a new NameContext.  The pNext field points to the
+** NameContext in the parent query.  Thus the process of scanning the
+** NameContext list corresponds to searching through successively outer
+** subqueries looking for a match.
+*/
+struct NameContext {
+  Parse *pParse;       /* The parser */
+  SrcList *pSrcList;   /* One or more tables used to resolve names */
+  union {
+    ExprList *pEList;    /* Optional list of result-set columns */
+    AggInfo *pAggInfo;   /* Information about aggregates at this level */
+    Upsert *pUpsert;     /* ON CONFLICT clause information from an upsert */
+    int iBaseReg;        /* For TK_REGISTER when parsing RETURNING */
+  } uNC;
+  NameContext *pNext;  /* Next outer name context.  NULL for outermost */
+  int nRef;            /* Number of names resolved by this context */
+  int nNcErr;          /* Number of errors encountered while resolving names */
+  int ncFlags;         /* Zero or more NC_* flags defined below */
+  u32 nNestedSelect;   /* Number of nested selects using this NC */
+  Select *pWinSelect;  /* SELECT statement for any window functions */
+};
+
+/*
+** Allowed values for the NameContext, ncFlags field.
+**
+** Value constraints (all checked via assert()):
+**    NC_HasAgg    == SF_HasAgg       == EP_Agg
+**    NC_MinMaxAgg == SF_MinMaxAgg    == SQLITE_FUNC_MINMAX
+**    NC_OrderAgg  == SF_OrderByReqd  == SQLITE_FUNC_ANYORDER
+**    NC_HasWin    == EP_Win
+**
+*/
+#define NC_AllowAgg  0x000001 /* Aggregate functions are allowed here */
+#define NC_PartIdx   0x000002 /* True if resolving a partial index WHERE */
+#define NC_IsCheck   0x000004 /* True if resolving a CHECK constraint */
+#define NC_GenCol    0x000008 /* True for a GENERATED ALWAYS AS clause */
+#define NC_HasAgg    0x000010 /* One or more aggregate functions seen */
+#define NC_IdxExpr   0x000020 /* True if resolving columns of CREATE INDEX */
+#define NC_SelfRef   0x00002e /* Combo: PartIdx, isCheck, GenCol, and IdxExpr */
+#define NC_Subquery  0x000040 /* A subquery has been seen */
+#define NC_UEList    0x000080 /* True if uNC.pEList is used */
+#define NC_UAggInfo  0x000100 /* True if uNC.pAggInfo is used */
+#define NC_UUpsert   0x000200 /* True if uNC.pUpsert is used */
+#define NC_UBaseReg  0x000400 /* True if uNC.iBaseReg is used */
+#define NC_MinMaxAgg 0x001000 /* min/max aggregates seen.  See note above */
+/*                   0x002000 // available for reuse */
+#define NC_AllowWin  0x004000 /* Window functions are allowed here */
+#define NC_HasWin    0x008000 /* One or more window functions seen */
+#define NC_IsDDL     0x010000 /* Resolving names in a CREATE statement */
+#define NC_InAggFunc 0x020000 /* True if analyzing arguments to an agg func */
+#define NC_FromDDL   0x040000 /* SQL text comes from sqlite_schema */
+#define NC_NoSelect  0x080000 /* Do not descend into sub-selects */
+#define NC_Where     0x100000 /* Processing WHERE clause of a SELECT */
+#define NC_OrderAgg 0x8000000 /* Has an aggregate other than count/min/max */
+
+/*
+** An instance of the following object describes a single ON CONFLICT
+** clause in an upsert.
+**
+** The pUpsertTarget field is only set if the ON CONFLICT clause includes
+** conflict-target clause.  (In "ON CONFLICT(a,b)" the "(a,b)" is the
+** conflict-target clause.)  The pUpsertTargetWhere is the optional
+** WHERE clause used to identify partial unique indexes.
+**
+** pUpsertSet is the list of column=expr terms of the UPDATE statement.
+** The pUpsertSet field is NULL for a ON CONFLICT DO NOTHING.  The
+** pUpsertWhere is the WHERE clause for the UPDATE and is NULL if the
+** WHERE clause is omitted.
+*/
+struct Upsert {
+  ExprList *pUpsertTarget;  /* Optional description of conflict target */
+  Expr *pUpsertTargetWhere; /* WHERE clause for partial index targets */
+  ExprList *pUpsertSet;     /* The SET clause from an ON CONFLICT UPDATE */
+  Expr *pUpsertWhere;       /* WHERE clause for the ON CONFLICT UPDATE */
+  Upsert *pNextUpsert;      /* Next ON CONFLICT clause in the list */
+  u8 isDoUpdate;            /* True for DO UPDATE.  False for DO NOTHING */
+  u8 isDup;                 /* True if 2nd or later with same pUpsertIdx */
+  /* Above this point is the parse tree for the ON CONFLICT clauses.
+  ** The next group of fields stores intermediate data. */
+  void *pToFree;            /* Free memory when deleting the Upsert object */
+  /* All fields above are owned by the Upsert object and must be freed
+  ** when the Upsert is destroyed.  The fields below are used to transfer
+  ** information from the INSERT processing down into the UPDATE processing
+  ** while generating code.  The fields below are owned by the INSERT
+  ** statement and will be freed by INSERT processing. */
+  Index *pUpsertIdx;        /* UNIQUE constraint specified by pUpsertTarget */
+  SrcList *pUpsertSrc;      /* Table to be updated */
+  int regData;              /* First register holding array of VALUES */
+  int iDataCur;             /* Index of the data cursor */
+  int iIdxCur;              /* Index of the first index cursor */
+};
+
+/*
+** An instance of the following structure contains all information
+** needed to generate code for a single SELECT statement.
+**
+** See the header comment on the computeLimitRegisters() routine for a
+** detailed description of the meaning of the iLimit and iOffset fields.
+**
+** addrOpenEphm[] entries contain the address of OP_OpenEphemeral opcodes.
+** These addresses must be stored so that we can go back and fill in
+** the P4_KEYINFO and P2 parameters later.  Neither the KeyInfo nor
+** the number of columns in P2 can be computed at the same time
+** as the OP_OpenEphm instruction is coded because not
+** enough information about the compound query is known at that point.
+** The KeyInfo for addrOpenTran[0] and [1] contains collating sequences
+** for the result set.  The KeyInfo for addrOpenEphm[2] contains collating
+** sequences for the ORDER BY clause.
+*/
+struct Select {
+  u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
+  LogEst nSelectRow;     /* Estimated number of result rows */
+  u32 selFlags;          /* Various SF_* values */
+  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
+  u32 selId;             /* Unique identifier number for this SELECT */
+  int addrOpenEphm[2];   /* OP_OpenEphem opcodes related to this select */
+  ExprList *pEList;      /* The fields of the result */
+  SrcList *pSrc;         /* The FROM clause */
+  Expr *pWhere;          /* The WHERE clause */
+  ExprList *pGroupBy;    /* The GROUP BY clause */
+  Expr *pHaving;         /* The HAVING clause */
+  ExprList *pOrderBy;    /* The ORDER BY clause */
+  Select *pPrior;        /* Prior select in a compound select statement */
+  Select *pNext;         /* Next select to the left in a compound */
+  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
+  With *pWith;           /* WITH clause attached to this select. Or NULL. */
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  Window *pWin;          /* List of window functions */
+  Window *pWinDefn;      /* List of named window definitions */
+#endif
+};
+
+/*
+** Allowed values for Select.selFlags.  The "SF" prefix stands for
+** "Select Flag".
+**
+** Value constraints (all checked via assert())
+**     SF_HasAgg      == NC_HasAgg
+**     SF_MinMaxAgg   == NC_MinMaxAgg     == SQLITE_FUNC_MINMAX
+**     SF_OrderByReqd == NC_OrderAgg      == SQLITE_FUNC_ANYORDER
+**     SF_FixedLimit  == WHERE_USE_LIMIT
+*/
+#define SF_Distinct      0x0000001 /* Output should be DISTINCT */
+#define SF_All           0x0000002 /* Includes the ALL keyword */
+#define SF_Resolved      0x0000004 /* Identifiers have been resolved */
+#define SF_Aggregate     0x0000008 /* Contains agg functions or a GROUP BY */
+#define SF_HasAgg        0x0000010 /* Contains aggregate functions */
+#define SF_UsesEphemeral 0x0000020 /* Uses the OpenEphemeral opcode */
+#define SF_Expanded      0x0000040 /* sqlite3SelectExpand() called on this */
+#define SF_HasTypeInfo   0x0000080 /* FROM subqueries have Table metadata */
+#define SF_Compound      0x0000100 /* Part of a compound query */
+#define SF_Values        0x0000200 /* Synthesized from VALUES clause */
+#define SF_MultiValue    0x0000400 /* Single VALUES term with multiple rows */
+#define SF_NestedFrom    0x0000800 /* Part of a parenthesized FROM clause */
+#define SF_MinMaxAgg     0x0001000 /* Aggregate containing min() or max() */
+#define SF_Recursive     0x0002000 /* The recursive part of a recursive CTE */
+#define SF_FixedLimit    0x0004000 /* nSelectRow set by a constant LIMIT */
+#define SF_MaybeConvert  0x0008000 /* Need convertCompoundSelectToSubquery() */
+#define SF_Converted     0x0010000 /* By convertCompoundSelectToSubquery() */
+#define SF_IncludeHidden 0x0020000 /* Include hidden columns in output */
+#define SF_ComplexResult 0x0040000 /* Result contains subquery or function */
+#define SF_WhereBegin    0x0080000 /* Really a WhereBegin() call.  Debug Only */
+#define SF_WinRewrite    0x0100000 /* Window function rewrite accomplished */
+#define SF_View          0x0200000 /* SELECT statement is a view */
+#define SF_NoopOrderBy   0x0400000 /* ORDER BY is ignored for this query */
+#define SF_UFSrcCheck    0x0800000 /* Check pSrc as required by UPDATE...FROM */
+#define SF_PushDown      0x1000000 /* Modified by WHERE-clause push-down opt */
+#define SF_MultiPart     0x2000000 /* Has multiple incompatible PARTITIONs */
+#define SF_CopyCte       0x4000000 /* SELECT statement is a copy of a CTE */
+#define SF_OrderByReqd   0x8000000 /* The ORDER BY clause may not be omitted */
+#define SF_UpdateFrom   0x10000000 /* Query originates with UPDATE FROM */
+#define SF_Correlated   0x20000000 /* True if references the outer context */
+
+/* True if SrcItem X is a subquery that has SF_NestedFrom */
+#define IsNestedFrom(X) \
+   ((X)->fg.isSubquery && \
+    ((X)->u4.pSubq->pSelect->selFlags&SF_NestedFrom)!=0)
+
+/*
+** The results of a SELECT can be distributed in several ways, as defined
+** by one of the following macros.  The "SRT" prefix means "SELECT Result
+** Type".
+**
+**     SRT_Union       Store results as a key in a temporary index
+**                     identified by pDest->iSDParm.
+**
+**     SRT_Except      Remove results from the temporary index pDest->iSDParm.
+**
+**     SRT_Exists      Store a 1 in memory cell pDest->iSDParm if the result
+**                     set is not empty.
+**
+**     SRT_Discard     Throw the results away.  This is used by SELECT
+**                     statements within triggers whose only purpose is
+**                     the side-effects of functions.
+**
+**     SRT_Output      Generate a row of output (using the OP_ResultRow
+**                     opcode) for each row in the result set.
+**
+**     SRT_Mem         Only valid if the result is a single column.
+**                     Store the first column of the first result row
+**                     in register pDest->iSDParm then abandon the rest
+**                     of the query.  This destination implies "LIMIT 1".
+**
+**     SRT_Set         The result must be a single column.  Store each
+**                     row of result as the key in table pDest->iSDParm.
+**                     Apply the affinity pDest->affSdst before storing
+**                     results.  if pDest->iSDParm2 is positive, then it is
+**                     a register holding a Bloom filter for the IN operator
+**                     that should be populated in addition to the
+**                     pDest->iSDParm table.  This SRT is used to
+**                     implement "IN (SELECT ...)".
+**
+**     SRT_EphemTab    Create an temporary table pDest->iSDParm and store
+**                     the result there. The cursor is left open after
+**                     returning.  This is like SRT_Table except that
+**                     this destination uses OP_OpenEphemeral to create
+**                     the table first.
+**
+**     SRT_Coroutine   Generate a co-routine that returns a new row of
+**                     results each time it is invoked.  The entry point
+**                     of the co-routine is stored in register pDest->iSDParm
+**                     and the result row is stored in pDest->nDest registers
+**                     starting with pDest->iSdst.
+**
+**     SRT_Table       Store results in temporary table pDest->iSDParm.
+**     SRT_Fifo        This is like SRT_EphemTab except that the table
+**                     is assumed to already be open.  SRT_Fifo has
+**                     the additional property of being able to ignore
+**                     the ORDER BY clause.
+**
+**     SRT_DistFifo    Store results in a temporary table pDest->iSDParm.
+**                     But also use temporary table pDest->iSDParm+1 as
+**                     a record of all prior results and ignore any duplicate
+**                     rows.  Name means:  "Distinct Fifo".
+**
+**     SRT_Queue       Store results in priority queue pDest->iSDParm (really
+**                     an index).  Append a sequence number so that all entries
+**                     are distinct.
+**
+**     SRT_DistQueue   Store results in priority queue pDest->iSDParm only if
+**                     the same record has never been stored before.  The
+**                     index at pDest->iSDParm+1 hold all prior stores.
+**
+**     SRT_Upfrom      Store results in the temporary table already opened by
+**                     pDest->iSDParm. If (pDest->iSDParm<0), then the temp
+**                     table is an intkey table - in this case the first
+**                     column returned by the SELECT is used as the integer
+**                     key. If (pDest->iSDParm>0), then the table is an index
+**                     table. (pDest->iSDParm) is the number of key columns in
+**                     each index record in this case.
+*/
+#define SRT_Union        1  /* Store result as keys in an index */
+#define SRT_Except       2  /* Remove result from a UNION index */
+#define SRT_Exists       3  /* Store 1 if the result is not empty */
+#define SRT_Discard      4  /* Do not save the results anywhere */
+#define SRT_DistFifo     5  /* Like SRT_Fifo, but unique results only */
+#define SRT_DistQueue    6  /* Like SRT_Queue, but unique results only */
+
+/* The DISTINCT clause is ignored for all of the above.  Not that
+** IgnorableDistinct() implies IgnorableOrderby() */
+#define IgnorableDistinct(X) ((X->eDest)<=SRT_DistQueue)
+
+#define SRT_Queue        7  /* Store result in an queue */
+#define SRT_Fifo         8  /* Store result as data with an automatic rowid */
+
+/* The ORDER BY clause is ignored for all of the above */
+#define IgnorableOrderby(X) ((X->eDest)<=SRT_Fifo)
+
+#define SRT_Output       9  /* Output each row of result */
+#define SRT_Mem         10  /* Store result in a memory cell */
+#define SRT_Set         11  /* Store results as keys in an index */
+#define SRT_EphemTab    12  /* Create transient tab and store like SRT_Table */
+#define SRT_Coroutine   13  /* Generate a single row of result */
+#define SRT_Table       14  /* Store result as data with an automatic rowid */
+#define SRT_Upfrom      15  /* Store result as data with rowid */
+
+/*
+** An instance of this object describes where to put of the results of
+** a SELECT statement.
+*/
+struct SelectDest {
+  u8 eDest;            /* How to dispose of the results.  One of SRT_* above. */
+  int iSDParm;         /* A parameter used by the eDest disposal method */
+  int iSDParm2;        /* A second parameter for the eDest disposal method */
+  int iSdst;           /* Base register where results are written */
+  int nSdst;           /* Number of registers allocated */
+  char *zAffSdst;      /* Affinity used for SRT_Set */
+  ExprList *pOrderBy;  /* Key columns for SRT_Queue and SRT_DistQueue */
+};
+
+/*
+** During code generation of statements that do inserts into AUTOINCREMENT
+** tables, the following information is attached to the Table.u.autoInc.p
+** pointer of each autoincrement table to record some side information that
+** the code generator needs.  We have to keep per-table autoincrement
+** information in case inserts are done within triggers.  Triggers do not
+** normally coordinate their activities, but we do need to coordinate the
+** loading and saving of autoincrement information.
+*/
+struct AutoincInfo {
+  AutoincInfo *pNext;   /* Next info block in a list of them all */
+  Table *pTab;          /* Table this info block refers to */
+  int iDb;              /* Index in sqlite3.aDb[] of database holding pTab */
+  int regCtr;           /* Memory register holding the rowid counter */
+};
+
+/*
+** At least one instance of the following structure is created for each
+** trigger that may be fired while parsing an INSERT, UPDATE or DELETE
+** statement. All such objects are stored in the linked list headed at
+** Parse.pTriggerPrg and deleted once statement compilation has been
+** completed.
+**
+** A Vdbe sub-program that implements the body and WHEN clause of trigger
+** TriggerPrg.pTrigger, assuming a default ON CONFLICT clause of
+** TriggerPrg.orconf, is stored in the TriggerPrg.pProgram variable.
+** The Parse.pTriggerPrg list never contains two entries with the same
+** values for both pTrigger and orconf.
+**
+** The TriggerPrg.aColmask[0] variable is set to a mask of old.* columns
+** accessed (or set to 0 for triggers fired as a result of INSERT
+** statements). Similarly, the TriggerPrg.aColmask[1] variable is set to
+** a mask of new.* columns used by the program.
+*/
+struct TriggerPrg {
+  Trigger *pTrigger;      /* Trigger this program was coded from */
+  TriggerPrg *pNext;      /* Next entry in Parse.pTriggerPrg list */
+  SubProgram *pProgram;   /* Program implementing pTrigger/orconf */
+  int orconf;             /* Default ON CONFLICT policy */
+  u32 aColmask[2];        /* Masks of old.*, new.* columns accessed */
+};
+
+/*
+** The yDbMask datatype for the bitmask of all attached databases.
+*/
+#if SQLITE_MAX_ATTACHED>30
+  typedef unsigned char yDbMask[(SQLITE_MAX_ATTACHED+9)/8];
+# define DbMaskTest(M,I)    (((M)[(I)/8]&(1<<((I)&7)))!=0)
+# define DbMaskZero(M)      memset((M),0,sizeof(M))
+# define DbMaskSet(M,I)     (M)[(I)/8]|=(1<<((I)&7))
+# define DbMaskAllZero(M)   sqlite3DbMaskAllZero(M)
+# define DbMaskNonZero(M)   (sqlite3DbMaskAllZero(M)==0)
+#else
+  typedef unsigned int yDbMask;
+# define DbMaskTest(M,I)    (((M)&(((yDbMask)1)<<(I)))!=0)
+# define DbMaskZero(M)      ((M)=0)
+# define DbMaskSet(M,I)     ((M)|=(((yDbMask)1)<<(I)))
+# define DbMaskAllZero(M)   ((M)==0)
+# define DbMaskNonZero(M)   ((M)!=0)
+#endif
+
+/*
+** For each index X that has as one of its arguments either an expression
+** or the name of a virtual generated column, and if X is in scope such that
+** the value of the expression can simply be read from the index, then
+** there is an instance of this object on the Parse.pIdxExpr list.
+**
+** During code generation, while generating code to evaluate expressions,
+** this list is consulted and if a matching expression is found, the value
+** is read from the index rather than being recomputed.
+*/
+struct IndexedExpr {
+  Expr *pExpr;            /* The expression contained in the index */
+  int iDataCur;           /* The data cursor associated with the index */
+  int iIdxCur;            /* The index cursor */
+  int iIdxCol;            /* The index column that contains value of pExpr */
+  u8 bMaybeNullRow;       /* True if we need an OP_IfNullRow check */
+  u8 aff;                 /* Affinity of the pExpr expression */
+  IndexedExpr *pIENext;   /* Next in a list of all indexed expressions */
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  const char *zIdxName;   /* Name of index, used only for bytecode comments */
+#endif
+};
+
+/*
+** An instance of the ParseCleanup object specifies an operation that
+** should be performed after parsing to deallocation resources obtained
+** during the parse and which are no longer needed.
+*/
+struct ParseCleanup {
+  ParseCleanup *pNext;               /* Next cleanup task */
+  void *pPtr;                        /* Pointer to object to deallocate */
+  void (*xCleanup)(sqlite3*,void*);  /* Deallocation routine */
+};
+
+/*
+** An SQL parser context.  A copy of this structure is passed through
+** the parser and down into all the parser action routine in order to
+** carry around information that is global to the entire parse.
+**
+** The structure is divided into two parts.  When the parser and code
+** generate call themselves recursively, the first part of the structure
+** is constant but the second part is reset at the beginning and end of
+** each recursion.
+**
+** The nTableLock and aTableLock variables are only used if the shared-cache
+** feature is enabled (if sqlite3Tsd()->useSharedData is true). They are
+** used to store the set of table-locks required by the statement being
+** compiled. Function sqlite3TableLock() is used to add entries to the
+** list.
+*/
+struct Parse {
+  sqlite3 *db;         /* The main database structure */
+  char *zErrMsg;       /* An error message */
+  Vdbe *pVdbe;         /* An engine for executing database bytecode */
+  int rc;              /* Return code from execution */
+  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
+  u8 checkSchema;      /* Causes schema cookie check after an error */
+  u8 nested;           /* Number of nested calls to the parser/code generator */
+  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
+  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
+  u8 mayAbort;         /* True if statement may throw an ABORT exception */
+  u8 hasCompound;      /* Need to invoke convertCompoundSelectToSubquery() */
+  u8 okConstFactor;    /* OK to factor out constants */
+  u8 disableLookaside; /* Number of times lookaside has been disabled */
+  u8 prepFlags;        /* SQLITE_PREPARE_* flags */
+  u8 withinRJSubrtn;   /* Nesting level for RIGHT JOIN body subroutines */
+  u8 bHasWith;         /* True if statement contains WITH */
+  u8 mSubrtnSig;       /* mini Bloom filter on available SubrtnSig.selId */
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+  u8 earlyCleanup;     /* OOM inside sqlite3ParserAddCleanup() */
+#endif
+#ifdef SQLITE_DEBUG
+  u8 ifNotExists;      /* Might be true if IF NOT EXISTS.  Assert()s only */
+#endif
+  int nRangeReg;       /* Size of the temporary register block */
+  int iRangeReg;       /* First register in temporary register block */
+  int nErr;            /* Number of errors seen */
+  int nTab;            /* Number of previously allocated VDBE cursors */
+  int nMem;            /* Number of memory cells used so far */
+  int szOpAlloc;       /* Bytes of memory space allocated for Vdbe.aOp[] */
+  int iSelfTab;        /* Table associated with an index on expr, or negative
+                       ** of the base register during check-constraint eval */
+  int nLabel;          /* The *negative* of the number of labels used */
+  int nLabelAlloc;     /* Number of slots in aLabel */
+  int *aLabel;         /* Space to hold the labels */
+  ExprList *pConstExpr;/* Constant expressions */
+  IndexedExpr *pIdxEpr;/* List of expressions used by active indexes */
+  IndexedExpr *pIdxPartExpr; /* Exprs constrained by index WHERE clauses */
+  Token constraintName;/* Name of the constraint currently being parsed */
+  yDbMask writeMask;   /* Start a write transaction on these databases */
+  yDbMask cookieMask;  /* Bitmask of schema verified databases */
+  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
+  int regRoot;         /* Register holding root page number for new objects */
+  int nMaxArg;         /* Max args passed to user function by sub-program */
+  int nSelect;         /* Number of SELECT stmts. Counter for Select.selId */
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  u32 nProgressSteps;  /* xProgress steps taken during sqlite3_prepare() */
+#endif
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  int nTableLock;        /* Number of locks in aTableLock */
+  TableLock *aTableLock; /* Required table locks for shared-cache mode */
+#endif
+  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */
+  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
+  Table *pTriggerTab;  /* Table triggers are being coded for */
+  TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
+  ParseCleanup *pCleanup;   /* List of cleanup operations to run after parse */
+  union {
+    int addrCrTab;         /* Address of OP_CreateBtree on CREATE TABLE */
+    Returning *pReturning; /* The RETURNING clause */
+  } u1;
+  u32 oldmask;         /* Mask of old.* columns referenced */
+  u32 newmask;         /* Mask of new.* columns referenced */
+  LogEst nQueryLoop;   /* Est number of iterations of a query (10*log2(N)) */
+  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
+  u8 bReturning;       /* Coding a RETURNING trigger */
+  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
+  u8 disableTriggers;  /* True to disable triggers */
+
+  /**************************************************************************
+  ** Fields above must be initialized to zero.  The fields that follow,
+  ** down to the beginning of the recursive section, do not need to be
+  ** initialized as they will be set before being used.  The boundary is
+  ** determined by offsetof(Parse,aTempReg).
+  **************************************************************************/
+
+  int aTempReg[8];        /* Holding area for temporary registers */
+  Parse *pOuterParse;     /* Outer Parse object when nested */
+  Token sNameToken;       /* Token with unqualified schema object name */
+
+  /************************************************************************
+  ** Above is constant between recursions.  Below is reset before and after
+  ** each recursion.  The boundary between these two regions is determined
+  ** using offsetof(Parse,sLastToken) so the sLastToken field must be the
+  ** first field in the recursive region.
+  ************************************************************************/
+
+  Token sLastToken;       /* The last token parsed */
+  ynVar nVar;               /* Number of '?' variables seen in the SQL so far */
+  u8 iPkSortOrder;          /* ASC or DESC for INTEGER PRIMARY KEY */
+  u8 explain;               /* True if the EXPLAIN flag is found on the query */
+  u8 eParseMode;            /* PARSE_MODE_XXX constant */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  int nVtabLock;            /* Number of virtual tables to lock */
+#endif
+  int nHeight;              /* Expression tree height of current sub-select */
+  int addrExplain;          /* Address of current OP_Explain opcode */
+  VList *pVList;            /* Mapping between variable names and numbers */
+  Vdbe *pReprepare;         /* VM being reprepared (sqlite3Reprepare()) */
+  const char *zTail;        /* All SQL text past the last semicolon parsed */
+  Table *pNewTable;         /* A table being constructed by CREATE TABLE */
+  Index *pNewIndex;         /* An index being constructed by CREATE INDEX.
+                            ** Also used to hold redundant UNIQUE constraints
+                            ** during a RENAME COLUMN */
+  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
+  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  Token sArg;               /* Complete text of a module argument */
+  Table **apVtabLock;       /* Pointer to virtual tables needing locking */
+#endif
+  With *pWith;              /* Current WITH clause, or NULL */
+#ifndef SQLITE_OMIT_ALTERTABLE
+  RenameToken *pRename;     /* Tokens subject to renaming by ALTER TABLE */
+#endif
+};
+
+/* Allowed values for Parse.eParseMode
+*/
+#define PARSE_MODE_NORMAL        0
+#define PARSE_MODE_DECLARE_VTAB  1
+#define PARSE_MODE_RENAME        2
+#define PARSE_MODE_UNMAP         3
+
+/*
+** Sizes and pointers of various parts of the Parse object.
+*/
+#define PARSE_HDR(X)  (((char*)(X))+offsetof(Parse,zErrMsg))
+#define PARSE_HDR_SZ (offsetof(Parse,aTempReg)-offsetof(Parse,zErrMsg)) /* Recursive part w/o aColCache*/
+#define PARSE_RECURSE_SZ offsetof(Parse,sLastToken)    /* Recursive part */
+#define PARSE_TAIL_SZ (sizeof(Parse)-PARSE_RECURSE_SZ) /* Non-recursive part */
+#define PARSE_TAIL(X) (((char*)(X))+PARSE_RECURSE_SZ)  /* Pointer to tail */
+
+/*
+** Return true if currently inside an sqlite3_declare_vtab() call.
+*/
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+  #define IN_DECLARE_VTAB 0
+#else
+  #define IN_DECLARE_VTAB (pParse->eParseMode==PARSE_MODE_DECLARE_VTAB)
+#endif
+
+#if defined(SQLITE_OMIT_ALTERTABLE)
+  #define IN_RENAME_OBJECT 0
+#else
+  #define IN_RENAME_OBJECT (pParse->eParseMode>=PARSE_MODE_RENAME)
+#endif
+
+#if defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_OMIT_ALTERTABLE)
+  #define IN_SPECIAL_PARSE 0
+#else
+  #define IN_SPECIAL_PARSE (pParse->eParseMode!=PARSE_MODE_NORMAL)
+#endif
+
+/*
+** An instance of the following structure can be declared on a stack and used
+** to save the Parse.zAuthContext value so that it can be restored later.
+*/
+struct AuthContext {
+  const char *zAuthContext;   /* Put saved Parse.zAuthContext here */
+  Parse *pParse;              /* The Parse structure */
+};
+
+/*
+** Bitfield flags for P5 value in various opcodes.
+**
+** Value constraints (enforced via assert()):
+**    OPFLAG_LENGTHARG    == SQLITE_FUNC_LENGTH
+**    OPFLAG_TYPEOFARG    == SQLITE_FUNC_TYPEOF
+**    OPFLAG_BULKCSR      == BTREE_BULKLOAD
+**    OPFLAG_SEEKEQ       == BTREE_SEEK_EQ
+**    OPFLAG_FORDELETE    == BTREE_FORDELETE
+**    OPFLAG_SAVEPOSITION == BTREE_SAVEPOSITION
+**    OPFLAG_AUXDELETE    == BTREE_AUXDELETE
+*/
+#define OPFLAG_NCHANGE       0x01    /* OP_Insert: Set to update db->nChange */
+                                     /* Also used in P2 (not P5) of OP_Delete */
+#define OPFLAG_NOCHNG        0x01    /* OP_VColumn nochange for UPDATE */
+#define OPFLAG_EPHEM         0x01    /* OP_Column: Ephemeral output is ok */
+#define OPFLAG_LASTROWID     0x20    /* Set to update db->lastRowid */
+#define OPFLAG_ISUPDATE      0x04    /* This OP_Insert is an sql UPDATE */
+#define OPFLAG_APPEND        0x08    /* This is likely to be an append */
+#define OPFLAG_USESEEKRESULT 0x10    /* Try to avoid a seek in BtreeInsert() */
+#define OPFLAG_ISNOOP        0x40    /* OP_Delete does pre-update-hook only */
+#define OPFLAG_LENGTHARG     0x40    /* OP_Column only used for length() */
+#define OPFLAG_TYPEOFARG     0x80    /* OP_Column only used for typeof() */
+#define OPFLAG_BYTELENARG    0xc0    /* OP_Column only for octet_length() */
+#define OPFLAG_BULKCSR       0x01    /* OP_Open** used to open bulk cursor */
+#define OPFLAG_SEEKEQ        0x02    /* OP_Open** cursor uses EQ seek only */
+#define OPFLAG_FORDELETE     0x08    /* OP_Open should use BTREE_FORDELETE */
+#define OPFLAG_P2ISREG       0x10    /* P2 to OP_Open** is a register number */
+#define OPFLAG_PERMUTE       0x01    /* OP_Compare: use the permutation */
+#define OPFLAG_SAVEPOSITION  0x02    /* OP_Delete/Insert: save cursor pos */
+#define OPFLAG_AUXDELETE     0x04    /* OP_Delete: index in a DELETE op */
+#define OPFLAG_NOCHNG_MAGIC  0x6d    /* OP_MakeRecord: serialtype 10 is ok */
+#define OPFLAG_PREFORMAT     0x80    /* OP_Insert uses preformatted cell */
+
+/*
+** Each trigger present in the database schema is stored as an instance of
+** struct Trigger.
+**
+** Pointers to instances of struct Trigger are stored in two ways.
+** 1. In the "trigHash" hash table (part of the sqlite3* that represents the
+**    database). This allows Trigger structures to be retrieved by name.
+** 2. All triggers associated with a single table form a linked list, using the
+**    pNext member of struct Trigger. A pointer to the first element of the
+**    linked list is stored as the "pTrigger" member of the associated
+**    struct Table.
+**
+** The "step_list" member points to the first element of a linked list
+** containing the SQL statements specified as the trigger program.
+*/
+struct Trigger {
+  char *zName;            /* The name of the trigger                        */
+  char *table;            /* The table or view to which the trigger applies */
+  u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
+  u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
+  u8 bReturning;          /* This trigger implements a RETURNING clause */
+  Expr *pWhen;            /* The WHEN clause of the expression (may be NULL) */
+  IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
+                             the <column-list> is stored here */
+  Schema *pSchema;        /* Schema containing the trigger */
+  Schema *pTabSchema;     /* Schema containing the table */
+  TriggerStep *step_list; /* Link list of trigger program steps             */
+  Trigger *pNext;         /* Next trigger associated with the table */
+};
+
+/*
+** A trigger is either a BEFORE or an AFTER trigger.  The following constants
+** determine which.
+**
+** If there are multiple triggers, you might of some BEFORE and some AFTER.
+** In that cases, the constants below can be ORed together.
+*/
+#define TRIGGER_BEFORE  1
+#define TRIGGER_AFTER   2
+
+/*
+** An instance of struct TriggerStep is used to store a single SQL statement
+** that is a part of a trigger-program.
+**
+** Instances of struct TriggerStep are stored in a singly linked list (linked
+** using the "pNext" member) referenced by the "step_list" member of the
+** associated struct Trigger instance. The first element of the linked list is
+** the first step of the trigger-program.
+**
+** The "op" member indicates whether this is a "DELETE", "INSERT", "UPDATE" or
+** "SELECT" statement. The meanings of the other members is determined by the
+** value of "op" as follows:
+**
+** (op == TK_INSERT)
+** orconf    -> stores the ON CONFLICT algorithm
+** pSelect   -> The content to be inserted - either a SELECT statement or
+**              a VALUES clause.
+** zTarget   -> Dequoted name of the table to insert into.
+** pIdList   -> If this is an INSERT INTO ... (<column-names>) VALUES ...
+**              statement, then this stores the column-names to be
+**              inserted into.
+** pUpsert   -> The ON CONFLICT clauses for an Upsert
+**
+** (op == TK_DELETE)
+** zTarget   -> Dequoted name of the table to delete from.
+** pWhere    -> The WHERE clause of the DELETE statement if one is specified.
+**              Otherwise NULL.
+**
+** (op == TK_UPDATE)
+** zTarget   -> Dequoted name of the table to update.
+** pWhere    -> The WHERE clause of the UPDATE statement if one is specified.
+**              Otherwise NULL.
+** pExprList -> A list of the columns to update and the expressions to update
+**              them to. See sqlite3Update() documentation of "pChanges"
+**              argument.
+**
+** (op == TK_SELECT)
+** pSelect   -> The SELECT statement
+**
+** (op == TK_RETURNING)
+** pExprList -> The list of expressions that follow the RETURNING keyword.
+**
+*/
+struct TriggerStep {
+  u8 op;               /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT,
+                       ** or TK_RETURNING */
+  u8 orconf;           /* OE_Rollback etc. */
+  Trigger *pTrig;      /* The trigger that this step is a part of */
+  Select *pSelect;     /* SELECT statement or RHS of INSERT INTO SELECT ... */
+  char *zTarget;       /* Target table for DELETE, UPDATE, INSERT */
+  SrcList *pFrom;      /* FROM clause for UPDATE statement (if any) */
+  Expr *pWhere;        /* The WHERE clause for DELETE or UPDATE steps */
+  ExprList *pExprList; /* SET clause for UPDATE, or RETURNING clause */
+  IdList *pIdList;     /* Column names for INSERT */
+  Upsert *pUpsert;     /* Upsert clauses on an INSERT */
+  char *zSpan;         /* Original SQL text of this command */
+  TriggerStep *pNext;  /* Next in the link-list */
+  TriggerStep *pLast;  /* Last element in link-list. Valid for 1st elem only */
+};
+
+/*
+** Information about a RETURNING clause
+*/
+struct Returning {
+  Parse *pParse;        /* The parse that includes the RETURNING clause */
+  ExprList *pReturnEL;  /* List of expressions to return */
+  Trigger retTrig;      /* The transient trigger that implements RETURNING */
+  TriggerStep retTStep; /* The trigger step */
+  int iRetCur;          /* Transient table holding RETURNING results */
+  int nRetCol;          /* Number of in pReturnEL after expansion */
+  int iRetReg;          /* Register array for holding a row of RETURNING */
+  char zName[40];       /* Name of trigger: "sqlite_returning_%p" */
+};
+
+/*
+** An object used to accumulate the text of a string where we
+** do not necessarily know how big the string will be in the end.
+*/
+struct sqlite3_str {
+  sqlite3 *db;         /* Optional database for lookaside.  Can be NULL */
+  char *zText;         /* The string collected so far */
+  u32  nAlloc;         /* Amount of space allocated in zText */
+  u32  mxAlloc;        /* Maximum allowed allocation.  0 for no malloc usage */
+  u32  nChar;          /* Length of the string so far */
+  u8   accError;       /* SQLITE_NOMEM or SQLITE_TOOBIG */
+  u8   printfFlags;    /* SQLITE_PRINTF flags below */
+};
+#define SQLITE_PRINTF_INTERNAL 0x01  /* Internal-use-only converters allowed */
+#define SQLITE_PRINTF_SQLFUNC  0x02  /* SQL function arguments to VXPrintf */
+#define SQLITE_PRINTF_MALLOCED 0x04  /* True if zText is allocated space */
+
+#define isMalloced(X)  (((X)->printfFlags & SQLITE_PRINTF_MALLOCED)!=0)
+
+/*
+** The following object is the header for an "RCStr" or "reference-counted
+** string".  An RCStr is passed around and used like any other char*
+** that has been dynamically allocated.  The important interface
+** differences:
+**
+**   1.  RCStr strings are reference counted.  They are deallocated
+**       when the reference count reaches zero.
+**
+**   2.  Use sqlite3RCStrUnref() to free an RCStr string rather than
+**       sqlite3_free()
+**
+**   3.  Make a (read-only) copy of a read-only RCStr string using
+**       sqlite3RCStrRef().
+**
+** "String" is in the name, but an RCStr object can also be used to hold
+** binary data.
+*/
+struct RCStr {
+  u64 nRCRef;            /* Number of references */
+  /* Total structure size should be a multiple of 8 bytes for alignment */
+};
+
+/*
+** A pointer to this structure is used to communicate information
+** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
+*/
+typedef struct {
+  sqlite3 *db;        /* The database being initialized */
+  char **pzErrMsg;    /* Error message stored here */
+  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
+  int rc;             /* Result code stored here */
+  u32 mInitFlags;     /* Flags controlling error messages */
+  u32 nInitRow;       /* Number of rows processed */
+  Pgno mxPage;        /* Maximum page number.  0 for no limit. */
+} InitData;
+
+/*
+** Allowed values for mInitFlags
+*/
+#define INITFLAG_AlterMask     0x0003  /* Types of ALTER */
+#define INITFLAG_AlterRename   0x0001  /* Reparse after a RENAME */
+#define INITFLAG_AlterDrop     0x0002  /* Reparse after a DROP COLUMN */
+#define INITFLAG_AlterAdd      0x0003  /* Reparse after an ADD COLUMN */
+
+/* Tuning parameters are set using SQLITE_TESTCTRL_TUNE and are controlled
+** on debug-builds of the CLI using ".testctrl tune ID VALUE".  Tuning
+** parameters are for temporary use during development, to help find
+** optimal values for parameters in the query planner.  The should not
+** be used on trunk check-ins.  They are a temporary mechanism available
+** for transient development builds only.
+**
+** Tuning parameters are numbered starting with 1.
+*/
+#define SQLITE_NTUNE  6             /* Should be zero for all trunk check-ins */
+#ifdef SQLITE_DEBUG
+# define Tuning(X)  (sqlite3Config.aTune[(X)-1])
+#else
+# define Tuning(X)  0
+#endif
+
+/*
+** Structure containing global configuration data for the SQLite library.
+**
+** This structure also contains some state information.
+*/
+struct Sqlite3Config {
+  int bMemstat;                     /* True to enable memory status */
+  u8 bCoreMutex;                    /* True to enable core mutexing */
+  u8 bFullMutex;                    /* True to enable full mutexing */
+  u8 bOpenUri;                      /* True to interpret filenames as URIs */
+  u8 bUseCis;                       /* Use covering indices for full-scans */
+  u8 bSmallMalloc;                  /* Avoid large memory allocations if true */
+  u8 bExtraSchemaChecks;            /* Verify type,name,tbl_name in schema */
+#ifdef SQLITE_DEBUG
+  u8 bJsonSelfcheck;                /* Double-check JSON parsing */
+#endif
+  int mxStrlen;                     /* Maximum string length */
+  int neverCorrupt;                 /* Database is always well-formed */
+  int szLookaside;                  /* Default lookaside buffer size */
+  int nLookaside;                   /* Default lookaside buffer count */
+  int nStmtSpill;                   /* Stmt-journal spill-to-disk threshold */
+  sqlite3_mem_methods m;            /* Low-level memory allocation interface */
+  sqlite3_mutex_methods mutex;      /* Low-level mutex interface */
+  sqlite3_pcache_methods2 pcache2;  /* Low-level page-cache interface */
+  void *pHeap;                      /* Heap storage space */
+  int nHeap;                        /* Size of pHeap[] */
+  int mnReq, mxReq;                 /* Min and max heap requests sizes */
+  sqlite3_int64 szMmap;             /* mmap() space per open file */
+  sqlite3_int64 mxMmap;             /* Maximum value for szMmap */
+  void *pPage;                      /* Page cache memory */
+  int szPage;                       /* Size of each page in pPage[] */
+  int nPage;                        /* Number of pages in pPage[] */
+  int mxParserStack;                /* maximum depth of the parser stack */
+  int sharedCacheEnabled;           /* true if shared-cache mode enabled */
+  u32 szPma;                        /* Maximum Sorter PMA size */
+  /* The above might be initialized to non-zero.  The following need to always
+  ** initially be zero, however. */
+  int isInit;                       /* True after initialization has finished */
+  int inProgress;                   /* True while initialization in progress */
+  int isMutexInit;                  /* True after mutexes are initialized */
+  int isMallocInit;                 /* True after malloc is initialized */
+  int isPCacheInit;                 /* True after malloc is initialized */
+  int nRefInitMutex;                /* Number of users of pInitMutex */
+  sqlite3_mutex *pInitMutex;        /* Mutex used by sqlite3_initialize() */
+  void (*xLog)(void*,int,const char*); /* Function for logging */
+  void *pLogArg;                       /* First argument to xLog() */
+#ifdef SQLITE_ENABLE_SQLLOG
+  void(*xSqllog)(void*,sqlite3*,const char*, int);
+  void *pSqllogArg;
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  /* The following callback (if not NULL) is invoked on every VDBE branch
+  ** operation.  Set the callback using SQLITE_TESTCTRL_VDBE_COVERAGE.
+  */
+  void (*xVdbeBranch)(void*,unsigned iSrcLine,u8 eThis,u8 eMx);  /* Callback */
+  void *pVdbeBranchArg;                                     /* 1st argument */
+#endif
+#ifndef SQLITE_OMIT_DESERIALIZE
+  sqlite3_int64 mxMemdbSize;        /* Default max memdb size */
+#endif
+#ifndef SQLITE_UNTESTABLE
+  int (*xTestCallback)(int);        /* Invoked by sqlite3FaultSim() */
+#endif
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  u32 mNoVisibleRowid;              /* TF_NoVisibleRowid if the ROWID_IN_VIEW
+                                    ** feature is disabled.  0 if rowids can
+                                    ** occur in views. */
+#endif
+  int bLocaltimeFault;              /* True to fail localtime() calls */
+  int (*xAltLocaltime)(const void*,void*); /* Alternative localtime() routine */
+  int iOnceResetThreshold;          /* When to reset OP_Once counters */
+  u32 szSorterRef;                  /* Min size in bytes to use sorter-refs */
+  unsigned int iPrngSeed;           /* Alternative fixed seed for the PRNG */
+  /* vvvv--- must be last ---vvv */
+#ifdef SQLITE_DEBUG
+  sqlite3_int64 aTune[SQLITE_NTUNE]; /* Tuning parameters */
+#endif
+};
+
+/*
+** This macro is used inside of assert() statements to indicate that
+** the assert is only valid on a well-formed database.  Instead of:
+**
+**     assert( X );
+**
+** One writes:
+**
+**     assert( X || CORRUPT_DB );
+**
+** CORRUPT_DB is true during normal operation.  CORRUPT_DB does not indicate
+** that the database is definitely corrupt, only that it might be corrupt.
+** For most test cases, CORRUPT_DB is set to false using a special
+** sqlite3_test_control().  This enables assert() statements to prove
+** things that are always true for well-formed databases.
+*/
+#define CORRUPT_DB  (sqlite3Config.neverCorrupt==0)
+
+/*
+** Context pointer passed down through the tree-walk.
+*/
+struct Walker {
+  Parse *pParse;                            /* Parser context.  */
+  int (*xExprCallback)(Walker*, Expr*);     /* Callback for expressions */
+  int (*xSelectCallback)(Walker*,Select*);  /* Callback for SELECTs */
+  void (*xSelectCallback2)(Walker*,Select*);/* Second callback for SELECTs */
+  int walkerDepth;                          /* Number of subqueries */
+  u16 eCode;                                /* A small processing code */
+  u16 mWFlags;                              /* Use-dependent flags */
+  union {                                   /* Extra data for callback */
+    NameContext *pNC;                         /* Naming context */
+    int n;                                    /* A counter */
+    int iCur;                                 /* A cursor number */
+    SrcList *pSrcList;                        /* FROM clause */
+    struct CCurHint *pCCurHint;               /* Used by codeCursorHint() */
+    struct RefSrcList *pRefSrcList;           /* sqlite3ReferencesSrcList() */
+    int *aiCol;                               /* array of column indexes */
+    struct IdxCover *pIdxCover;               /* Check for index coverage */
+    ExprList *pGroupBy;                       /* GROUP BY clause */
+    Select *pSelect;                          /* HAVING to WHERE clause ctx */
+    struct WindowRewrite *pRewrite;           /* Window rewrite context */
+    struct WhereConst *pConst;                /* WHERE clause constants */
+    struct RenameCtx *pRename;                /* RENAME COLUMN context */
+    struct Table *pTab;                       /* Table of generated column */
+    struct CoveringIndexCheck *pCovIdxCk;     /* Check for covering index */
+    SrcItem *pSrcItem;                        /* A single FROM clause item */
+    DbFixer *pFix;                            /* See sqlite3FixSelect() */
+    Mem *aMem;                                /* See sqlite3BtreeCursorHint() */
+  } u;
+};
+
+/*
+** The following structure contains information used by the sqliteFix...
+** routines as they walk the parse tree to make database references
+** explicit.
+*/
+struct DbFixer {
+  Parse *pParse;      /* The parsing context.  Error messages written here */
+  Walker w;           /* Walker object */
+  Schema *pSchema;    /* Fix items to this schema */
+  u8 bTemp;           /* True for TEMP schema entries */
+  const char *zDb;    /* Make sure all objects are contained in this database */
+  const char *zType;  /* Type of the container - used for error messages */
+  const Token *pName; /* Name of the container - used for error messages */
+};
+
+/* Forward declarations */
+SQLITE_PRIVATE int sqlite3WalkExpr(Walker*, Expr*);
+SQLITE_PRIVATE int sqlite3WalkExprNN(Walker*, Expr*);
+SQLITE_PRIVATE int sqlite3WalkExprList(Walker*, ExprList*);
+SQLITE_PRIVATE int sqlite3WalkSelect(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3WalkSelectExpr(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3WalkSelectFrom(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3ExprWalkNoop(Walker*, Expr*);
+SQLITE_PRIVATE int sqlite3SelectWalkNoop(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3SelectWalkFail(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3WalkerDepthIncrease(Walker*,Select*);
+SQLITE_PRIVATE void sqlite3WalkerDepthDecrease(Walker*,Select*);
+SQLITE_PRIVATE void sqlite3WalkWinDefnDummyCallback(Walker*,Select*);
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE void sqlite3SelectWalkAssert2(Walker*, Select*);
+#endif
+
+#ifndef SQLITE_OMIT_CTE
+SQLITE_PRIVATE void sqlite3SelectPopWith(Walker*, Select*);
+#else
+# define sqlite3SelectPopWith 0
+#endif
+
+/*
+** Return code from the parse-tree walking primitives and their
+** callbacks.
+*/
+#define WRC_Continue    0   /* Continue down into children */
+#define WRC_Prune       1   /* Omit children but continue walking siblings */
+#define WRC_Abort       2   /* Abandon the tree walk */
+
+/*
+** A single common table expression
+*/
+struct Cte {
+  char *zName;            /* Name of this CTE */
+  ExprList *pCols;        /* List of explicit column names, or NULL */
+  Select *pSelect;        /* The definition of this CTE */
+  const char *zCteErr;    /* Error message for circular references */
+  CteUse *pUse;           /* Usage information for this CTE */
+  u8 eM10d;               /* The MATERIALIZED flag */
+};
+
+/*
+** Allowed values for the materialized flag (eM10d):
+*/
+#define M10d_Yes       0  /* AS MATERIALIZED */
+#define M10d_Any       1  /* Not specified.  Query planner's choice */
+#define M10d_No        2  /* AS NOT MATERIALIZED */
+
+/*
+** An instance of the With object represents a WITH clause containing
+** one or more CTEs (common table expressions).
+*/
+struct With {
+  int nCte;               /* Number of CTEs in the WITH clause */
+  int bView;              /* Belongs to the outermost Select of a view */
+  With *pOuter;           /* Containing WITH clause, or NULL */
+  Cte a[1];               /* For each CTE in the WITH clause.... */
+};
+
+/*
+** The Cte object is not guaranteed to persist for the entire duration
+** of code generation.  (The query flattener or other parser tree
+** edits might delete it.)  The following object records information
+** about each Common Table Expression that must be preserved for the
+** duration of the parse.
+**
+** The CteUse objects are freed using sqlite3ParserAddCleanup() rather
+** than sqlite3SelectDelete(), which is what enables them to persist
+** until the end of code generation.
+*/
+struct CteUse {
+  int nUse;              /* Number of users of this CTE */
+  int addrM9e;           /* Start of subroutine to compute materialization */
+  int regRtn;            /* Return address register for addrM9e subroutine */
+  int iCur;              /* Ephemeral table holding the materialization */
+  LogEst nRowEst;        /* Estimated number of rows in the table */
+  u8 eM10d;              /* The MATERIALIZED flag */
+};
+
+
+/* Client data associated with sqlite3_set_clientdata() and
+** sqlite3_get_clientdata().
+*/
+struct DbClientData {
+  DbClientData *pNext;        /* Next in a linked list */
+  void *pData;                /* The data */
+  void (*xDestructor)(void*); /* Destructor.  Might be NULL */
+  char zName[1];              /* Name of this client data. MUST BE LAST */
+};
+
+#ifdef SQLITE_DEBUG
+/*
+** An instance of the TreeView object is used for printing the content of
+** data structures on sqlite3DebugPrintf() using a tree-like view.
+*/
+struct TreeView {
+  int iLevel;             /* Which level of the tree we are on */
+  u8  bLine[100];         /* Draw vertical in column i if bLine[i] is true */
+};
+#endif /* SQLITE_DEBUG */
+
+/*
+** This object is used in various ways, most (but not all) related to window
+** functions.
+**
+**   (1) A single instance of this structure is attached to the
+**       the Expr.y.pWin field for each window function in an expression tree.
+**       This object holds the information contained in the OVER clause,
+**       plus additional fields used during code generation.
+**
+**   (2) All window functions in a single SELECT form a linked-list
+**       attached to Select.pWin.  The Window.pFunc and Window.pExpr
+**       fields point back to the expression that is the window function.
+**
+**   (3) The terms of the WINDOW clause of a SELECT are instances of this
+**       object on a linked list attached to Select.pWinDefn.
+**
+**   (4) For an aggregate function with a FILTER clause, an instance
+**       of this object is stored in Expr.y.pWin with eFrmType set to
+**       TK_FILTER. In this case the only field used is Window.pFilter.
+**
+** The uses (1) and (2) are really the same Window object that just happens
+** to be accessible in two different ways.  Use case (3) are separate objects.
+*/
+struct Window {
+  char *zName;            /* Name of window (may be NULL) */
+  char *zBase;            /* Name of base window for chaining (may be NULL) */
+  ExprList *pPartition;   /* PARTITION BY clause */
+  ExprList *pOrderBy;     /* ORDER BY clause */
+  u8 eFrmType;            /* TK_RANGE, TK_GROUPS, TK_ROWS, or 0 */
+  u8 eStart;              /* UNBOUNDED, CURRENT, PRECEDING or FOLLOWING */
+  u8 eEnd;                /* UNBOUNDED, CURRENT, PRECEDING or FOLLOWING */
+  u8 bImplicitFrame;      /* True if frame was implicitly specified */
+  u8 eExclude;            /* TK_NO, TK_CURRENT, TK_TIES, TK_GROUP, or 0 */
+  Expr *pStart;           /* Expression for "<expr> PRECEDING" */
+  Expr *pEnd;             /* Expression for "<expr> FOLLOWING" */
+  Window **ppThis;        /* Pointer to this object in Select.pWin list */
+  Window *pNextWin;       /* Next window function belonging to this SELECT */
+  Expr *pFilter;          /* The FILTER expression */
+  FuncDef *pWFunc;        /* The function */
+  int iEphCsr;            /* Partition buffer or Peer buffer */
+  int regAccum;           /* Accumulator */
+  int regResult;          /* Interim result */
+  int csrApp;             /* Function cursor (used by min/max) */
+  int regApp;             /* Function register (also used by min/max) */
+  int regPart;            /* Array of registers for PARTITION BY values */
+  Expr *pOwner;           /* Expression object this window is attached to */
+  int nBufferCol;         /* Number of columns in buffer table */
+  int iArgCol;            /* Offset of first argument for this function */
+  int regOne;             /* Register containing constant value 1 */
+  int regStartRowid;
+  int regEndRowid;
+  u8 bExprArgs;           /* Defer evaluation of window function arguments
+                          ** due to the SQLITE_SUBTYPE flag */
+};
+
+SQLITE_PRIVATE Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow);
+SQLITE_PRIVATE void sqlite3MultiValuesEnd(Parse *pParse, Select *pVal);
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE void sqlite3WindowDelete(sqlite3*, Window*);
+SQLITE_PRIVATE void sqlite3WindowUnlinkFromSelect(Window*);
+SQLITE_PRIVATE void sqlite3WindowListDelete(sqlite3 *db, Window *p);
+SQLITE_PRIVATE Window *sqlite3WindowAlloc(Parse*, int, int, Expr*, int , Expr*, u8);
+SQLITE_PRIVATE void sqlite3WindowAttach(Parse*, Expr*, Window*);
+SQLITE_PRIVATE void sqlite3WindowLink(Select *pSel, Window *pWin);
+SQLITE_PRIVATE int sqlite3WindowCompare(const Parse*, const Window*, const Window*, int);
+SQLITE_PRIVATE void sqlite3WindowCodeInit(Parse*, Select*);
+SQLITE_PRIVATE void sqlite3WindowCodeStep(Parse*, Select*, WhereInfo*, int, int);
+SQLITE_PRIVATE int sqlite3WindowRewrite(Parse*, Select*);
+SQLITE_PRIVATE void sqlite3WindowUpdate(Parse*, Window*, Window*, FuncDef*);
+SQLITE_PRIVATE Window *sqlite3WindowDup(sqlite3 *db, Expr *pOwner, Window *p);
+SQLITE_PRIVATE Window *sqlite3WindowListDup(sqlite3 *db, Window *p);
+SQLITE_PRIVATE void sqlite3WindowFunctions(void);
+SQLITE_PRIVATE void sqlite3WindowChain(Parse*, Window*, Window*);
+SQLITE_PRIVATE Window *sqlite3WindowAssemble(Parse*, Window*, ExprList*, ExprList*, Token*);
+#else
+# define sqlite3WindowDelete(a,b)
+# define sqlite3WindowFunctions()
+# define sqlite3WindowAttach(a,b,c)
+#endif
+
+/*
+** Assuming zIn points to the first byte of a UTF-8 character,
+** advance zIn to point to the first byte of the next UTF-8 character.
+*/
+#define SQLITE_SKIP_UTF8(zIn) {                        \
+  if( (*(zIn++))>=0xc0 ){                              \
+    while( (*zIn & 0xc0)==0x80 ){ zIn++; }             \
+  }                                                    \
+}
+
+/*
+** The SQLITE_*_BKPT macros are substitutes for the error codes with
+** the same name but without the _BKPT suffix.  These macros invoke
+** routines that report the line-number on which the error originated
+** using sqlite3_log().  The routines also provide a convenient place
+** to set a debugger breakpoint.
+*/
+SQLITE_PRIVATE int sqlite3ReportError(int iErr, int lineno, const char *zType);
+SQLITE_PRIVATE int sqlite3CorruptError(int);
+SQLITE_PRIVATE int sqlite3MisuseError(int);
+SQLITE_PRIVATE int sqlite3CantopenError(int);
+#define SQLITE_CORRUPT_BKPT sqlite3CorruptError(__LINE__)
+#define SQLITE_MISUSE_BKPT sqlite3MisuseError(__LINE__)
+#define SQLITE_CANTOPEN_BKPT sqlite3CantopenError(__LINE__)
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   int sqlite3NomemError(int);
+SQLITE_PRIVATE   int sqlite3IoerrnomemError(int);
+# define SQLITE_NOMEM_BKPT sqlite3NomemError(__LINE__)
+# define SQLITE_IOERR_NOMEM_BKPT sqlite3IoerrnomemError(__LINE__)
+#else
+# define SQLITE_NOMEM_BKPT SQLITE_NOMEM
+# define SQLITE_IOERR_NOMEM_BKPT SQLITE_IOERR_NOMEM
+#endif
+#if defined(SQLITE_DEBUG) || defined(SQLITE_ENABLE_CORRUPT_PGNO)
+SQLITE_PRIVATE   int sqlite3CorruptPgnoError(int,Pgno);
+# define SQLITE_CORRUPT_PGNO(P) sqlite3CorruptPgnoError(__LINE__,(P))
+#else
+# define SQLITE_CORRUPT_PGNO(P) sqlite3CorruptError(__LINE__)
+#endif
+
+/*
+** FTS3 and FTS4 both require virtual table support
+*/
+#if defined(SQLITE_OMIT_VIRTUALTABLE)
+# undef SQLITE_ENABLE_FTS3
+# undef SQLITE_ENABLE_FTS4
+#endif
+
+/*
+** FTS4 is really an extension for FTS3.  It is enabled using the
+** SQLITE_ENABLE_FTS3 macro.  But to avoid confusion we also call
+** the SQLITE_ENABLE_FTS4 macro to serve as an alias for SQLITE_ENABLE_FTS3.
+*/
+#if defined(SQLITE_ENABLE_FTS4) && !defined(SQLITE_ENABLE_FTS3)
+# define SQLITE_ENABLE_FTS3 1
+#endif
+
+/*
+** The following macros mimic the standard library functions toupper(),
+** isspace(), isalnum(), isdigit() and isxdigit(), respectively. The
+** sqlite versions only work for ASCII characters, regardless of locale.
+*/
+#ifdef SQLITE_ASCII
+# define sqlite3Toupper(x)  ((x)&~(sqlite3CtypeMap[(unsigned char)(x)]&0x20))
+# define sqlite3Isspace(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x01)
+# define sqlite3Isalnum(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x06)
+# define sqlite3Isalpha(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x02)
+# define sqlite3Isdigit(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x04)
+# define sqlite3Isxdigit(x)  (sqlite3CtypeMap[(unsigned char)(x)]&0x08)
+# define sqlite3Tolower(x)   (sqlite3UpperToLower[(unsigned char)(x)])
+# define sqlite3Isquote(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x80)
+# define sqlite3JsonId1(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x42)
+# define sqlite3JsonId2(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x46)
+#else
+# define sqlite3Toupper(x)   toupper((unsigned char)(x))
+# define sqlite3Isspace(x)   isspace((unsigned char)(x))
+# define sqlite3Isalnum(x)   isalnum((unsigned char)(x))
+# define sqlite3Isalpha(x)   isalpha((unsigned char)(x))
+# define sqlite3Isdigit(x)   isdigit((unsigned char)(x))
+# define sqlite3Isxdigit(x)  isxdigit((unsigned char)(x))
+# define sqlite3Tolower(x)   tolower((unsigned char)(x))
+# define sqlite3Isquote(x)   ((x)=='"'||(x)=='\''||(x)=='['||(x)=='`')
+# define sqlite3JsonId1(x)   (sqlite3IsIdChar(x)&&(x)<'0')
+# define sqlite3JsonId2(x)   sqlite3IsIdChar(x)
+#endif
+SQLITE_PRIVATE int sqlite3IsIdChar(u8);
+
+/*
+** Internal function prototypes
+*/
+SQLITE_PRIVATE int sqlite3StrICmp(const char*,const char*);
+SQLITE_PRIVATE int sqlite3Strlen30(const char*);
+#define sqlite3Strlen30NN(C) (strlen(C)&0x3fffffff)
+SQLITE_PRIVATE char *sqlite3ColumnType(Column*,char*);
+#define sqlite3StrNICmp sqlite3_strnicmp
+
+SQLITE_PRIVATE int sqlite3MallocInit(void);
+SQLITE_PRIVATE void sqlite3MallocEnd(void);
+SQLITE_PRIVATE void *sqlite3Malloc(u64);
+SQLITE_PRIVATE void *sqlite3MallocZero(u64);
+SQLITE_PRIVATE void *sqlite3DbMallocZero(sqlite3*, u64);
+SQLITE_PRIVATE void *sqlite3DbMallocRaw(sqlite3*, u64);
+SQLITE_PRIVATE void *sqlite3DbMallocRawNN(sqlite3*, u64);
+SQLITE_PRIVATE char *sqlite3DbStrDup(sqlite3*,const char*);
+SQLITE_PRIVATE char *sqlite3DbStrNDup(sqlite3*,const char*, u64);
+SQLITE_PRIVATE char *sqlite3DbSpanDup(sqlite3*,const char*,const char*);
+SQLITE_PRIVATE void *sqlite3Realloc(void*, u64);
+SQLITE_PRIVATE void *sqlite3DbReallocOrFree(sqlite3 *, void *, u64);
+SQLITE_PRIVATE void *sqlite3DbRealloc(sqlite3 *, void *, u64);
+SQLITE_PRIVATE void sqlite3DbFree(sqlite3*, void*);
+SQLITE_PRIVATE void sqlite3DbFreeNN(sqlite3*, void*);
+SQLITE_PRIVATE void sqlite3DbNNFreeNN(sqlite3*, void*);
+SQLITE_PRIVATE int sqlite3MallocSize(const void*);
+SQLITE_PRIVATE int sqlite3DbMallocSize(sqlite3*, const void*);
+SQLITE_PRIVATE void *sqlite3PageMalloc(int);
+SQLITE_PRIVATE void sqlite3PageFree(void*);
+SQLITE_PRIVATE void sqlite3MemSetDefault(void);
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE void sqlite3BenignMallocHooks(void (*)(void), void (*)(void));
+#endif
+SQLITE_PRIVATE int sqlite3HeapNearlyFull(void);
+
+/*
+** On systems with ample stack space and that support alloca(), make
+** use of alloca() to obtain space for large automatic objects.  By default,
+** obtain space from malloc().
+**
+** The alloca() routine never returns NULL.  This will cause code paths
+** that deal with sqlite3StackAlloc() failures to be unreachable.
+*/
+#ifdef SQLITE_USE_ALLOCA
+# define sqlite3StackAllocRaw(D,N)   alloca(N)
+# define sqlite3StackAllocRawNN(D,N) alloca(N)
+# define sqlite3StackFree(D,P)
+# define sqlite3StackFreeNN(D,P)
+#else
+# define sqlite3StackAllocRaw(D,N)   sqlite3DbMallocRaw(D,N)
+# define sqlite3StackAllocRawNN(D,N) sqlite3DbMallocRawNN(D,N)
+# define sqlite3StackFree(D,P)       sqlite3DbFree(D,P)
+# define sqlite3StackFreeNN(D,P)     sqlite3DbFreeNN(D,P)
+#endif
+
+/* Do not allow both MEMSYS5 and MEMSYS3 to be defined together.  If they
+** are, disable MEMSYS3
+*/
+#ifdef SQLITE_ENABLE_MEMSYS5
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys5(void);
+#undef SQLITE_ENABLE_MEMSYS3
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS3
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys3(void);
+#endif
+
+
+#ifndef SQLITE_MUTEX_OMIT
+SQLITE_PRIVATE   sqlite3_mutex_methods const *sqlite3DefaultMutex(void);
+SQLITE_PRIVATE   sqlite3_mutex_methods const *sqlite3NoopMutex(void);
+SQLITE_PRIVATE   sqlite3_mutex *sqlite3MutexAlloc(int);
+SQLITE_PRIVATE   int sqlite3MutexInit(void);
+SQLITE_PRIVATE   int sqlite3MutexEnd(void);
+#endif
+#if !defined(SQLITE_MUTEX_OMIT) && !defined(SQLITE_MUTEX_NOOP)
+SQLITE_PRIVATE   void sqlite3MemoryBarrier(void);
+#else
+# define sqlite3MemoryBarrier()
+#endif
+
+SQLITE_PRIVATE sqlite3_int64 sqlite3StatusValue(int);
+SQLITE_PRIVATE void sqlite3StatusUp(int, int);
+SQLITE_PRIVATE void sqlite3StatusDown(int, int);
+SQLITE_PRIVATE void sqlite3StatusHighwater(int, int);
+SQLITE_PRIVATE int sqlite3LookasideUsed(sqlite3*,int*);
+
+/* Access to mutexes used by sqlite3_status() */
+SQLITE_PRIVATE sqlite3_mutex *sqlite3Pcache1Mutex(void);
+SQLITE_PRIVATE sqlite3_mutex *sqlite3MallocMutex(void);
+
+#if defined(SQLITE_ENABLE_MULTITHREADED_CHECKS) && !defined(SQLITE_MUTEX_OMIT)
+SQLITE_PRIVATE void sqlite3MutexWarnOnContention(sqlite3_mutex*);
+#else
+# define sqlite3MutexWarnOnContention(x)
+#endif
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+# define EXP754 (((u64)0x7ff)<<52)
+# define MAN754 ((((u64)1)<<52)-1)
+# define IsNaN(X) (((X)&EXP754)==EXP754 && ((X)&MAN754)!=0)
+# define IsOvfl(X) (((X)&EXP754)==EXP754)
+SQLITE_PRIVATE   int sqlite3IsNaN(double);
+SQLITE_PRIVATE   int sqlite3IsOverflow(double);
+#else
+# define IsNaN(X)             0
+# define sqlite3IsNaN(X)      0
+# define sqlite3IsOVerflow(X) 0
+#endif
+
+/*
+** An instance of the following structure holds information about SQL
+** functions arguments that are the parameters to the printf() function.
+*/
+struct PrintfArguments {
+  int nArg;                /* Total number of arguments */
+  int nUsed;               /* Number of arguments used so far */
+  sqlite3_value **apArg;   /* The argument values */
+};
+
+/*
+** An instance of this object receives the decoding of a floating point
+** value into an approximate decimal representation.
+*/
+struct FpDecode {
+  char sign;           /* '+' or '-' */
+  char isSpecial;      /* 1: Infinity  2: NaN */
+  int n;               /* Significant digits in the decode */
+  int iDP;             /* Location of the decimal point */
+  char *z;             /* Start of significant digits */
+  char zBuf[24];       /* Storage for significant digits */
+};
+
+SQLITE_PRIVATE void sqlite3FpDecode(FpDecode*,double,int,int);
+SQLITE_PRIVATE char *sqlite3MPrintf(sqlite3*,const char*, ...);
+SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3*,const char*, va_list);
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+SQLITE_PRIVATE   void sqlite3DebugPrintf(const char*, ...);
+#endif
+#if defined(SQLITE_TEST)
+SQLITE_PRIVATE   void *sqlite3TestTextToPtr(const char*);
+#endif
+
+#if defined(SQLITE_DEBUG)
+SQLITE_PRIVATE   void sqlite3TreeViewLine(TreeView*, const char *zFormat, ...);
+SQLITE_PRIVATE   void sqlite3TreeViewExpr(TreeView*, const Expr*, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewBareExprList(TreeView*, const ExprList*, const char*);
+SQLITE_PRIVATE   void sqlite3TreeViewExprList(TreeView*, const ExprList*, u8, const char*);
+SQLITE_PRIVATE   void sqlite3TreeViewBareIdList(TreeView*, const IdList*, const char*);
+SQLITE_PRIVATE   void sqlite3TreeViewIdList(TreeView*, const IdList*, u8, const char*);
+SQLITE_PRIVATE   void sqlite3TreeViewColumnList(TreeView*, const Column*, int, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewSrcList(TreeView*, const SrcList*);
+SQLITE_PRIVATE   void sqlite3TreeViewSelect(TreeView*, const Select*, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewWith(TreeView*, const With*, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewUpsert(TreeView*, const Upsert*, u8);
+#if TREETRACE_ENABLED
+SQLITE_PRIVATE   void sqlite3TreeViewDelete(const With*, const SrcList*, const Expr*,
+                             const ExprList*,const Expr*, const Trigger*);
+SQLITE_PRIVATE   void sqlite3TreeViewInsert(const With*, const SrcList*,
+                             const IdList*, const Select*, const ExprList*,
+                             int, const Upsert*, const Trigger*);
+SQLITE_PRIVATE   void sqlite3TreeViewUpdate(const With*, const SrcList*, const ExprList*,
+                             const Expr*, int, const ExprList*, const Expr*,
+                             const Upsert*, const Trigger*);
+#endif
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE   void sqlite3TreeViewTriggerStep(TreeView*, const TriggerStep*, u8, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewTrigger(TreeView*, const Trigger*, u8, u8);
+#endif
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE   void sqlite3TreeViewWindow(TreeView*, const Window*, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewWinFunc(TreeView*, const Window*, u8);
+#endif
+SQLITE_PRIVATE   void sqlite3ShowExpr(const Expr*);
+SQLITE_PRIVATE   void sqlite3ShowExprList(const ExprList*);
+SQLITE_PRIVATE   void sqlite3ShowIdList(const IdList*);
+SQLITE_PRIVATE   void sqlite3ShowSrcList(const SrcList*);
+SQLITE_PRIVATE   void sqlite3ShowSelect(const Select*);
+SQLITE_PRIVATE   void sqlite3ShowWith(const With*);
+SQLITE_PRIVATE   void sqlite3ShowUpsert(const Upsert*);
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE   void sqlite3ShowTriggerStep(const TriggerStep*);
+SQLITE_PRIVATE   void sqlite3ShowTriggerStepList(const TriggerStep*);
+SQLITE_PRIVATE   void sqlite3ShowTrigger(const Trigger*);
+SQLITE_PRIVATE   void sqlite3ShowTriggerList(const Trigger*);
+#endif
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE   void sqlite3ShowWindow(const Window*);
+SQLITE_PRIVATE   void sqlite3ShowWinFunc(const Window*);
+#endif
+#endif
+
+SQLITE_PRIVATE void sqlite3SetString(char **, sqlite3*, const char*);
+SQLITE_PRIVATE void sqlite3ProgressCheck(Parse*);
+SQLITE_PRIVATE void sqlite3ErrorMsg(Parse*, const char*, ...);
+SQLITE_PRIVATE int sqlite3ErrorToParser(sqlite3*,int);
+SQLITE_PRIVATE void sqlite3Dequote(char*);
+SQLITE_PRIVATE void sqlite3DequoteExpr(Expr*);
+SQLITE_PRIVATE void sqlite3DequoteToken(Token*);
+SQLITE_PRIVATE void sqlite3DequoteNumber(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3TokenInit(Token*,char*);
+SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char*, int);
+SQLITE_PRIVATE int sqlite3RunParser(Parse*, const char*);
+SQLITE_PRIVATE void sqlite3FinishCoding(Parse*);
+SQLITE_PRIVATE int sqlite3GetTempReg(Parse*);
+SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse*,int);
+SQLITE_PRIVATE int sqlite3GetTempRange(Parse*,int);
+SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse*,int,int);
+SQLITE_PRIVATE void sqlite3ClearTempRegCache(Parse*);
+SQLITE_PRIVATE void sqlite3TouchRegister(Parse*,int);
+#if defined(SQLITE_ENABLE_STAT4) || defined(SQLITE_DEBUG)
+SQLITE_PRIVATE int sqlite3FirstAvailableRegister(Parse*,int);
+#endif
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3NoTempsInRange(Parse*,int,int);
+#endif
+SQLITE_PRIVATE Expr *sqlite3ExprAlloc(sqlite3*,int,const Token*,int);
+SQLITE_PRIVATE Expr *sqlite3Expr(sqlite3*,int,const char*);
+SQLITE_PRIVATE void sqlite3ExprAttachSubtrees(sqlite3*,Expr*,Expr*,Expr*);
+SQLITE_PRIVATE Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*);
+SQLITE_PRIVATE void sqlite3PExprAddSelect(Parse*, Expr*, Select*);
+SQLITE_PRIVATE Expr *sqlite3ExprAnd(Parse*,Expr*, Expr*);
+SQLITE_PRIVATE Expr *sqlite3ExprSimplifiedAndOr(Expr*);
+SQLITE_PRIVATE Expr *sqlite3ExprFunction(Parse*,ExprList*, const Token*, int);
+SQLITE_PRIVATE void sqlite3ExprAddFunctionOrderBy(Parse*,Expr*,ExprList*);
+SQLITE_PRIVATE void sqlite3ExprOrderByAggregateError(Parse*,Expr*);
+SQLITE_PRIVATE void sqlite3ExprFunctionUsable(Parse*,const Expr*,const FuncDef*);
+SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse*, Expr*, u32);
+SQLITE_PRIVATE void sqlite3ExprDelete(sqlite3*, Expr*);
+SQLITE_PRIVATE void sqlite3ExprDeleteGeneric(sqlite3*,void*);
+SQLITE_PRIVATE int sqlite3ExprDeferredDelete(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3ExprUnmapAndDelete(Parse*, Expr*);
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(Parse*,ExprList*,Expr*);
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppendVector(Parse*,ExprList*,IdList*,Expr*);
+SQLITE_PRIVATE Select *sqlite3ExprListToValues(Parse*, int, ExprList*);
+SQLITE_PRIVATE void sqlite3ExprListSetSortOrder(ExprList*,int,int);
+SQLITE_PRIVATE void sqlite3ExprListSetName(Parse*,ExprList*,const Token*,int);
+SQLITE_PRIVATE void sqlite3ExprListSetSpan(Parse*,ExprList*,const char*,const char*);
+SQLITE_PRIVATE void sqlite3ExprListDelete(sqlite3*, ExprList*);
+SQLITE_PRIVATE void sqlite3ExprListDeleteGeneric(sqlite3*,void*);
+SQLITE_PRIVATE u32 sqlite3ExprListFlags(const ExprList*);
+SQLITE_PRIVATE int sqlite3IndexHasDuplicateRootPage(Index*);
+SQLITE_PRIVATE int sqlite3Init(sqlite3*, char**);
+SQLITE_PRIVATE int sqlite3InitCallback(void*, int, char**, char**);
+SQLITE_PRIVATE int sqlite3InitOne(sqlite3*, int, char**, u32);
+SQLITE_PRIVATE void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+SQLITE_PRIVATE Module *sqlite3PragmaVtabRegister(sqlite3*,const char *zName);
+#endif
+SQLITE_PRIVATE void sqlite3ResetAllSchemasOfConnection(sqlite3*);
+SQLITE_PRIVATE void sqlite3ResetOneSchema(sqlite3*,int);
+SQLITE_PRIVATE void sqlite3CollapseDatabaseArray(sqlite3*);
+SQLITE_PRIVATE void sqlite3CommitInternalChanges(sqlite3*);
+SQLITE_PRIVATE void sqlite3ColumnSetExpr(Parse*,Table*,Column*,Expr*);
+SQLITE_PRIVATE Expr *sqlite3ColumnExpr(Table*,Column*);
+SQLITE_PRIVATE void sqlite3ColumnSetColl(sqlite3*,Column*,const char*zColl);
+SQLITE_PRIVATE const char *sqlite3ColumnColl(Column*);
+SQLITE_PRIVATE void sqlite3DeleteColumnNames(sqlite3*,Table*);
+SQLITE_PRIVATE void sqlite3GenerateColumnNames(Parse *pParse, Select *pSelect);
+SQLITE_PRIVATE int sqlite3ColumnsFromExprList(Parse*,ExprList*,i16*,Column**);
+SQLITE_PRIVATE void sqlite3SubqueryColumnTypes(Parse*,Table*,Select*,char);
+SQLITE_PRIVATE Table *sqlite3ResultSetOfSelect(Parse*,Select*,char);
+SQLITE_PRIVATE void sqlite3OpenSchemaTable(Parse *, int);
+SQLITE_PRIVATE Index *sqlite3PrimaryKeyIndex(Table*);
+SQLITE_PRIVATE i16 sqlite3TableColumnToIndex(Index*, i16);
+#ifdef SQLITE_OMIT_GENERATED_COLUMNS
+# define sqlite3TableColumnToStorage(T,X) (X)  /* No-op pass-through */
+# define sqlite3StorageColumnToTable(T,X) (X)  /* No-op pass-through */
+#else
+SQLITE_PRIVATE   i16 sqlite3TableColumnToStorage(Table*, i16);
+SQLITE_PRIVATE   i16 sqlite3StorageColumnToTable(Table*, i16);
+#endif
+SQLITE_PRIVATE void sqlite3StartTable(Parse*,Token*,Token*,int,int,int,int);
+#if SQLITE_ENABLE_HIDDEN_COLUMNS
+SQLITE_PRIVATE   void sqlite3ColumnPropertiesFromName(Table*, Column*);
+#else
+# define sqlite3ColumnPropertiesFromName(T,C) /* no-op */
+#endif
+SQLITE_PRIVATE void sqlite3AddColumn(Parse*,Token,Token);
+SQLITE_PRIVATE void sqlite3AddNotNull(Parse*, int);
+SQLITE_PRIVATE void sqlite3AddPrimaryKey(Parse*, ExprList*, int, int, int);
+SQLITE_PRIVATE void sqlite3AddCheckConstraint(Parse*, Expr*, const char*, const char*);
+SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse*,Expr*,const char*,const char*);
+SQLITE_PRIVATE void sqlite3AddCollateType(Parse*, Token*);
+SQLITE_PRIVATE void sqlite3AddGenerated(Parse*,Expr*,Token*);
+SQLITE_PRIVATE void sqlite3EndTable(Parse*,Token*,Token*,u32,Select*);
+SQLITE_PRIVATE void sqlite3AddReturning(Parse*,ExprList*);
+SQLITE_PRIVATE int sqlite3ParseUri(const char*,const char*,unsigned int*,
+                    sqlite3_vfs**,char**,char **);
+#define sqlite3CodecQueryParameters(A,B,C) 0
+SQLITE_PRIVATE Btree *sqlite3DbNameToBtree(sqlite3*,const char*);
+
+#ifdef SQLITE_UNTESTABLE
+# define sqlite3FaultSim(X) SQLITE_OK
+#else
+SQLITE_PRIVATE   int sqlite3FaultSim(int);
+#endif
+
+SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32);
+SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec*, u32);
+SQLITE_PRIVATE int sqlite3BitvecTestNotNull(Bitvec*, u32);
+SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec*, u32);
+SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec*, u32, void*);
+SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec*);
+SQLITE_PRIVATE u32 sqlite3BitvecSize(Bitvec*);
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int,int*);
+#endif
+
+SQLITE_PRIVATE RowSet *sqlite3RowSetInit(sqlite3*);
+SQLITE_PRIVATE void sqlite3RowSetDelete(void*);
+SQLITE_PRIVATE void sqlite3RowSetClear(void*);
+SQLITE_PRIVATE void sqlite3RowSetInsert(RowSet*, i64);
+SQLITE_PRIVATE int sqlite3RowSetTest(RowSet*, int iBatch, i64);
+SQLITE_PRIVATE int sqlite3RowSetNext(RowSet*, i64*);
+
+SQLITE_PRIVATE void sqlite3CreateView(Parse*,Token*,Token*,Token*,ExprList*,Select*,int,int);
+
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+SQLITE_PRIVATE   int sqlite3ViewGetColumnNames(Parse*,Table*);
+#else
+# define sqlite3ViewGetColumnNames(A,B) 0
+#endif
+
+#if SQLITE_MAX_ATTACHED>30
+SQLITE_PRIVATE   int sqlite3DbMaskAllZero(yDbMask);
+#endif
+SQLITE_PRIVATE void sqlite3DropTable(Parse*, SrcList*, int, int);
+SQLITE_PRIVATE void sqlite3CodeDropTable(Parse*, Table*, int, int);
+SQLITE_PRIVATE void sqlite3DeleteTable(sqlite3*, Table*);
+SQLITE_PRIVATE void sqlite3DeleteTableGeneric(sqlite3*, void*);
+SQLITE_PRIVATE void sqlite3FreeIndex(sqlite3*, Index*);
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+SQLITE_PRIVATE   void sqlite3AutoincrementBegin(Parse *pParse);
+SQLITE_PRIVATE   void sqlite3AutoincrementEnd(Parse *pParse);
+#else
+# define sqlite3AutoincrementBegin(X)
+# define sqlite3AutoincrementEnd(X)
+#endif
+SQLITE_PRIVATE void sqlite3Insert(Parse*, SrcList*, Select*, IdList*, int, Upsert*);
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+SQLITE_PRIVATE   void sqlite3ComputeGeneratedColumns(Parse*, int, Table*);
+#endif
+SQLITE_PRIVATE void *sqlite3ArrayAllocate(sqlite3*,void*,int,int*,int*);
+SQLITE_PRIVATE IdList *sqlite3IdListAppend(Parse*, IdList*, Token*);
+SQLITE_PRIVATE int sqlite3IdListIndex(IdList*,const char*);
+SQLITE_PRIVATE SrcList *sqlite3SrcListEnlarge(Parse*, SrcList*, int, int);
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendList(Parse *pParse, SrcList *p1, SrcList *p2);
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppend(Parse*, SrcList*, Token*, Token*);
+SQLITE_PRIVATE void sqlite3SubqueryDelete(sqlite3*,Subquery*);
+SQLITE_PRIVATE Select *sqlite3SubqueryDetach(sqlite3*,SrcItem*);
+SQLITE_PRIVATE int sqlite3SrcItemAttachSubquery(Parse*, SrcItem*, Select*, int);
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendFromTerm(Parse*, SrcList*, Token*, Token*,
+                                      Token*, Select*, OnOrUsing*);
+SQLITE_PRIVATE void sqlite3SrcListIndexedBy(Parse *, SrcList *, Token *);
+SQLITE_PRIVATE void sqlite3SrcListFuncArgs(Parse*, SrcList*, ExprList*);
+SQLITE_PRIVATE int sqlite3IndexedByLookup(Parse *, SrcItem *);
+SQLITE_PRIVATE void sqlite3SrcListShiftJoinType(Parse*,SrcList*);
+SQLITE_PRIVATE void sqlite3SrcListAssignCursors(Parse*, SrcList*);
+SQLITE_PRIVATE void sqlite3IdListDelete(sqlite3*, IdList*);
+SQLITE_PRIVATE void sqlite3ClearOnOrUsing(sqlite3*, OnOrUsing*);
+SQLITE_PRIVATE void sqlite3SrcListDelete(sqlite3*, SrcList*);
+SQLITE_PRIVATE Index *sqlite3AllocateIndexObject(sqlite3*,i16,int,char**);
+SQLITE_PRIVATE void sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
+                          Expr*, int, int, u8);
+SQLITE_PRIVATE void sqlite3DropIndex(Parse*, SrcList*, int);
+SQLITE_PRIVATE int sqlite3Select(Parse*, Select*, SelectDest*);
+SQLITE_PRIVATE Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
+                         Expr*,ExprList*,u32,Expr*);
+SQLITE_PRIVATE void sqlite3SelectDelete(sqlite3*, Select*);
+SQLITE_PRIVATE void sqlite3SelectDeleteGeneric(sqlite3*,void*);
+SQLITE_PRIVATE Table *sqlite3SrcListLookup(Parse*, SrcList*);
+SQLITE_PRIVATE int sqlite3IsReadOnly(Parse*, Table*, Trigger*);
+SQLITE_PRIVATE void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
+#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
+SQLITE_PRIVATE Expr *sqlite3LimitWhere(Parse*,SrcList*,Expr*,ExprList*,Expr*,char*);
+#endif
+SQLITE_PRIVATE void sqlite3CodeChangeCount(Vdbe*,int,const char*);
+SQLITE_PRIVATE void sqlite3DeleteFrom(Parse*, SrcList*, Expr*, ExprList*, Expr*);
+SQLITE_PRIVATE void sqlite3Update(Parse*, SrcList*, ExprList*,Expr*,int,ExprList*,Expr*,
+                   Upsert*);
+SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(Parse*,SrcList*,Expr*,ExprList*,
+                             ExprList*,Select*,u16,int);
+SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo*);
+SQLITE_PRIVATE LogEst sqlite3WhereOutputRowCount(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereIsDistinct(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereIsOrdered(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereOrderByLimitOptLabel(WhereInfo*);
+SQLITE_PRIVATE void sqlite3WhereMinMaxOptEarlyOut(Vdbe*,WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereIsSorted(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereContinueLabel(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereBreakLabel(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereOkOnePass(WhereInfo*, int*);
+#define ONEPASS_OFF      0        /* Use of ONEPASS not allowed */
+#define ONEPASS_SINGLE   1        /* ONEPASS valid for a single row update */
+#define ONEPASS_MULTI    2        /* ONEPASS is valid for multiple rows */
+SQLITE_PRIVATE int sqlite3WhereUsesDeferredSeek(WhereInfo*);
+SQLITE_PRIVATE void sqlite3ExprCodeLoadIndexColumn(Parse*, Index*, int, int, int);
+SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, u8);
+SQLITE_PRIVATE void sqlite3ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
+SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse*, int, int, int);
+SQLITE_PRIVATE void sqlite3ExprToRegister(Expr *pExpr, int iReg);
+SQLITE_PRIVATE void sqlite3ExprCode(Parse*, Expr*, int);
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+SQLITE_PRIVATE void sqlite3ExprCodeGeneratedColumn(Parse*, Table*, Column*, int);
+#endif
+SQLITE_PRIVATE void sqlite3ExprCodeCopy(Parse*, Expr*, int);
+SQLITE_PRIVATE void sqlite3ExprCodeFactorable(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCodeRunJustOnce(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
+SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCodeExprList(Parse*, ExprList*, int, int, u8);
+#define SQLITE_ECEL_DUP      0x01  /* Deep, not shallow copies */
+#define SQLITE_ECEL_FACTOR   0x02  /* Factor out constant terms */
+#define SQLITE_ECEL_REF      0x04  /* Use ExprList.u.x.iOrderByCol */
+#define SQLITE_ECEL_OMITREF  0x08  /* Omit if ExprList.u.x.iOrderByCol */
+SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
+SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
+SQLITE_PRIVATE void sqlite3ExprIfFalseDup(Parse*, Expr*, int, int);
+SQLITE_PRIVATE Table *sqlite3FindTable(sqlite3*,const char*, const char*);
+#define LOCATE_VIEW    0x01
+#define LOCATE_NOERR   0x02
+SQLITE_PRIVATE Table *sqlite3LocateTable(Parse*,u32 flags,const char*, const char*);
+SQLITE_PRIVATE const char *sqlite3PreferredTableName(const char*);
+SQLITE_PRIVATE Table *sqlite3LocateTableItem(Parse*,u32 flags,SrcItem *);
+SQLITE_PRIVATE Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);
+SQLITE_PRIVATE void sqlite3Vacuum(Parse*,Token*,Expr*);
+SQLITE_PRIVATE int sqlite3RunVacuum(char**, sqlite3*, int, sqlite3_value*);
+SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3*, const Token*);
+SQLITE_PRIVATE int sqlite3ExprCompare(const Parse*,const Expr*,const Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCompareSkip(Expr*,Expr*,int);
+SQLITE_PRIVATE int sqlite3ExprListCompare(const ExprList*,const ExprList*, int);
+SQLITE_PRIVATE int sqlite3ExprImpliesExpr(const Parse*,const Expr*,const Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprImpliesNonNullRow(Expr*,int,int);
+SQLITE_PRIVATE void sqlite3AggInfoPersistWalkerInit(Walker*,Parse*);
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
+SQLITE_PRIVATE int sqlite3ExprCoveredByIndex(Expr*, int iCur, Index *pIdx);
+SQLITE_PRIVATE int sqlite3ReferencesSrcList(Parse*, Expr*, SrcList*);
+SQLITE_PRIVATE Vdbe *sqlite3GetVdbe(Parse*);
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE void sqlite3PrngSaveState(void);
+SQLITE_PRIVATE void sqlite3PrngRestoreState(void);
+#endif
+SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3*,int);
+SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse*, int);
+SQLITE_PRIVATE void sqlite3CodeVerifyNamedSchema(Parse*, const char *zDb);
+SQLITE_PRIVATE void sqlite3BeginTransaction(Parse*, int);
+SQLITE_PRIVATE void sqlite3EndTransaction(Parse*,int);
+SQLITE_PRIVATE void sqlite3Savepoint(Parse*, int, Token*);
+SQLITE_PRIVATE void sqlite3CloseSavepoints(sqlite3 *);
+SQLITE_PRIVATE void sqlite3LeaveMutexAndCloseZombie(sqlite3*);
+SQLITE_PRIVATE u32 sqlite3IsTrueOrFalse(const char*);
+SQLITE_PRIVATE int sqlite3ExprIdToTrueFalse(Expr*);
+SQLITE_PRIVATE int sqlite3ExprTruthValue(const Expr*);
+SQLITE_PRIVATE int sqlite3ExprIsConstant(Parse*,Expr*);
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr*, u8);
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrGroupBy(Parse*, Expr*, ExprList*);
+SQLITE_PRIVATE int sqlite3ExprIsSingleTableConstraint(Expr*,const SrcList*,int,int);
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+SQLITE_PRIVATE int sqlite3ExprContainsSubquery(Expr*);
+#endif
+SQLITE_PRIVATE int sqlite3ExprIsInteger(const Expr*, int*, Parse*);
+SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr*);
+SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr*, char);
+SQLITE_PRIVATE int sqlite3IsRowid(const char*);
+SQLITE_PRIVATE const char *sqlite3RowidAlias(Table *pTab);
+SQLITE_PRIVATE void sqlite3GenerateRowDelete(
+    Parse*,Table*,Trigger*,int,int,int,i16,u8,u8,u8,int);
+SQLITE_PRIVATE void sqlite3GenerateRowIndexDelete(Parse*, Table*, int, int, int*, int);
+SQLITE_PRIVATE int sqlite3GenerateIndexKey(Parse*, Index*, int, int, int, int*,Index*,int);
+SQLITE_PRIVATE void sqlite3ResolvePartIdxLabel(Parse*,int);
+SQLITE_PRIVATE int sqlite3ExprReferencesUpdatedColumn(Expr*,int*,int);
+SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(Parse*,Table*,int*,int,int,int,int,
+                                     u8,u8,int,int*,int*,Upsert*);
+#ifdef SQLITE_ENABLE_NULL_TRIM
+SQLITE_PRIVATE   void sqlite3SetMakeRecordP5(Vdbe*,Table*);
+#else
+# define sqlite3SetMakeRecordP5(A,B)
+#endif
+SQLITE_PRIVATE void sqlite3CompleteInsertion(Parse*,Table*,int,int,int,int*,int,int,int);
+SQLITE_PRIVATE int sqlite3OpenTableAndIndices(Parse*, Table*, int, u8, int, u8*, int*, int*);
+SQLITE_PRIVATE void sqlite3BeginWriteOperation(Parse*, int, int);
+SQLITE_PRIVATE void sqlite3MultiWrite(Parse*);
+SQLITE_PRIVATE void sqlite3MayAbort(Parse*);
+SQLITE_PRIVATE void sqlite3HaltConstraint(Parse*, int, int, char*, i8, u8);
+SQLITE_PRIVATE void sqlite3UniqueConstraint(Parse*, int, Index*);
+SQLITE_PRIVATE void sqlite3RowidConstraint(Parse*, int, Table*);
+SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3*,const Expr*,int);
+SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3*,const ExprList*,int);
+SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3*,const SrcList*,int);
+SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3*,const IdList*);
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3*,const Select*,int);
+SQLITE_PRIVATE FuncDef *sqlite3FunctionSearch(int,const char*);
+SQLITE_PRIVATE void sqlite3InsertBuiltinFuncs(FuncDef*,int);
+SQLITE_PRIVATE FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,u8,u8);
+SQLITE_PRIVATE void sqlite3QuoteValue(StrAccum*,sqlite3_value*);
+SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(void);
+SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void);
+SQLITE_PRIVATE void sqlite3RegisterJsonFunctions(void);
+SQLITE_PRIVATE void sqlite3RegisterPerConnectionBuiltinFunctions(sqlite3*);
+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_JSON)
+SQLITE_PRIVATE   int sqlite3JsonTableFunctions(sqlite3*);
+#endif
+SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3*);
+SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3*);
+SQLITE_PRIVATE void sqlite3ChangeCookie(Parse*, int);
+SQLITE_PRIVATE With *sqlite3WithDup(sqlite3 *db, With *p);
+
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+SQLITE_PRIVATE void sqlite3MaterializeView(Parse*, Table*, Expr*, ExprList*,Expr*,int);
+#endif
+
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE   void sqlite3BeginTrigger(Parse*, Token*,Token*,int,int,IdList*,SrcList*,
+                           Expr*,int, int);
+SQLITE_PRIVATE   void sqlite3FinishTrigger(Parse*, TriggerStep*, Token*);
+SQLITE_PRIVATE   void sqlite3DropTrigger(Parse*, SrcList*, int);
+SQLITE_PRIVATE   void sqlite3DropTriggerPtr(Parse*, Trigger*);
+SQLITE_PRIVATE   Trigger *sqlite3TriggersExist(Parse *, Table*, int, ExprList*, int *pMask);
+SQLITE_PRIVATE   Trigger *sqlite3TriggerList(Parse *, Table *);
+SQLITE_PRIVATE   void sqlite3CodeRowTrigger(Parse*, Trigger *, int, ExprList*, int, Table *,
+                            int, int, int);
+SQLITE_PRIVATE   void sqlite3CodeRowTriggerDirect(Parse *, Trigger *, Table *, int, int, int);
+  void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);
+SQLITE_PRIVATE   void sqlite3DeleteTriggerStep(sqlite3*, TriggerStep*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerSelectStep(sqlite3*,Select*,
+                                        const char*,const char*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerInsertStep(Parse*,Token*, IdList*,
+                                        Select*,u8,Upsert*,
+                                        const char*,const char*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerUpdateStep(Parse*,Token*,SrcList*,ExprList*,
+                                        Expr*, u8, const char*,const char*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerDeleteStep(Parse*,Token*, Expr*,
+                                        const char*,const char*);
+SQLITE_PRIVATE   void sqlite3DeleteTrigger(sqlite3*, Trigger*);
+SQLITE_PRIVATE   void sqlite3UnlinkAndDeleteTrigger(sqlite3*,int,const char*);
+SQLITE_PRIVATE   u32 sqlite3TriggerColmask(Parse*,Trigger*,ExprList*,int,int,Table*,int);
+SQLITE_PRIVATE   SrcList *sqlite3TriggerStepSrc(Parse*, TriggerStep*);
+# define sqlite3ParseToplevel(p) ((p)->pToplevel ? (p)->pToplevel : (p))
+# define sqlite3IsToplevel(p) ((p)->pToplevel==0)
+#else
+# define sqlite3TriggersExist(B,C,D,E,F) 0
+# define sqlite3DeleteTrigger(A,B)
+# define sqlite3DropTriggerPtr(A,B)
+# define sqlite3UnlinkAndDeleteTrigger(A,B,C)
+# define sqlite3CodeRowTrigger(A,B,C,D,E,F,G,H,I)
+# define sqlite3CodeRowTriggerDirect(A,B,C,D,E,F)
+# define sqlite3TriggerList(X, Y) 0
+# define sqlite3ParseToplevel(p) p
+# define sqlite3IsToplevel(p) 1
+# define sqlite3TriggerColmask(A,B,C,D,E,F,G) 0
+# define sqlite3TriggerStepSrc(A,B) 0
+#endif
+
+SQLITE_PRIVATE int sqlite3JoinType(Parse*, Token*, Token*, Token*);
+SQLITE_PRIVATE int sqlite3ColumnIndex(Table *pTab, const char *zCol);
+SQLITE_PRIVATE void sqlite3SrcItemColumnUsed(SrcItem*,int);
+SQLITE_PRIVATE void sqlite3SetJoinExpr(Expr*,int,u32);
+SQLITE_PRIVATE void sqlite3CreateForeignKey(Parse*, ExprList*, Token*, ExprList*, int);
+SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse*, int);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+SQLITE_PRIVATE   void sqlite3AuthRead(Parse*,Expr*,Schema*,SrcList*);
+SQLITE_PRIVATE   int sqlite3AuthCheck(Parse*,int, const char*, const char*, const char*);
+SQLITE_PRIVATE   void sqlite3AuthContextPush(Parse*, AuthContext*, const char*);
+SQLITE_PRIVATE   void sqlite3AuthContextPop(AuthContext*);
+SQLITE_PRIVATE   int sqlite3AuthReadCol(Parse*, const char *, const char *, int);
+#else
+# define sqlite3AuthRead(a,b,c,d)
+# define sqlite3AuthCheck(a,b,c,d,e)    SQLITE_OK
+# define sqlite3AuthContextPush(a,b,c)
+# define sqlite3AuthContextPop(a)  ((void)(a))
+#endif
+SQLITE_PRIVATE int sqlite3DbIsNamed(sqlite3 *db, int iDb, const char *zName);
+SQLITE_PRIVATE void sqlite3Attach(Parse*, Expr*, Expr*, Expr*);
+SQLITE_PRIVATE void sqlite3Detach(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3FixInit(DbFixer*, Parse*, int, const char*, const Token*);
+SQLITE_PRIVATE int sqlite3FixSrcList(DbFixer*, SrcList*);
+SQLITE_PRIVATE int sqlite3FixSelect(DbFixer*, Select*);
+SQLITE_PRIVATE int sqlite3FixExpr(DbFixer*, Expr*);
+SQLITE_PRIVATE int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);
+
+SQLITE_PRIVATE int sqlite3RealSameAsInt(double,sqlite3_int64);
+SQLITE_PRIVATE i64 sqlite3RealToI64(double);
+SQLITE_PRIVATE int sqlite3Int64ToText(i64,char*);
+SQLITE_PRIVATE int sqlite3AtoF(const char *z, double*, int, u8);
+SQLITE_PRIVATE int sqlite3GetInt32(const char *, int*);
+SQLITE_PRIVATE int sqlite3GetUInt32(const char*, u32*);
+SQLITE_PRIVATE int sqlite3Atoi(const char*);
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_PRIVATE int sqlite3Utf16ByteLen(const void *pData, int nByte, int nChar);
+#endif
+SQLITE_PRIVATE int sqlite3Utf8CharLen(const char *pData, int nByte);
+SQLITE_PRIVATE u32 sqlite3Utf8Read(const u8**);
+SQLITE_PRIVATE int sqlite3Utf8ReadLimited(const u8*, int, u32*);
+SQLITE_PRIVATE LogEst sqlite3LogEst(u64);
+SQLITE_PRIVATE LogEst sqlite3LogEstAdd(LogEst,LogEst);
+SQLITE_PRIVATE LogEst sqlite3LogEstFromDouble(double);
+SQLITE_PRIVATE u64 sqlite3LogEstToInt(LogEst);
+SQLITE_PRIVATE VList *sqlite3VListAdd(sqlite3*,VList*,const char*,int,int);
+SQLITE_PRIVATE const char *sqlite3VListNumToName(VList*,int);
+SQLITE_PRIVATE int sqlite3VListNameToNum(VList*,const char*,int);
+
+/*
+** Routines to read and write variable-length integers.  These used to
+** be defined locally, but now we use the varint routines in the util.c
+** file.
+*/
+SQLITE_PRIVATE int sqlite3PutVarint(unsigned char*, u64);
+SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *, u64 *);
+SQLITE_PRIVATE u8 sqlite3GetVarint32(const unsigned char *, u32 *);
+SQLITE_PRIVATE int sqlite3VarintLen(u64 v);
+
+/*
+** The common case is for a varint to be a single byte.  They following
+** macros handle the common case without a procedure call, but then call
+** the procedure for larger varints.
+*/
+#define getVarint32(A,B)  \
+  (u8)((*(A)<(u8)0x80)?((B)=(u32)*(A)),1:sqlite3GetVarint32((A),(u32 *)&(B)))
+#define getVarint32NR(A,B) \
+  B=(u32)*(A);if(B>=0x80)sqlite3GetVarint32((A),(u32*)&(B))
+#define putVarint32(A,B)  \
+  (u8)(((u32)(B)<(u32)0x80)?(*(A)=(unsigned char)(B)),1:\
+  sqlite3PutVarint((A),(B)))
+#define getVarint    sqlite3GetVarint
+#define putVarint    sqlite3PutVarint
+
+
+SQLITE_PRIVATE const char *sqlite3IndexAffinityStr(sqlite3*, Index*);
+SQLITE_PRIVATE char *sqlite3TableAffinityStr(sqlite3*,const Table*);
+SQLITE_PRIVATE void sqlite3TableAffinity(Vdbe*, Table*, int);
+SQLITE_PRIVATE char sqlite3CompareAffinity(const Expr *pExpr, char aff2);
+SQLITE_PRIVATE int sqlite3IndexAffinityOk(const Expr *pExpr, char idx_affinity);
+SQLITE_PRIVATE char sqlite3TableColumnAffinity(const Table*,int);
+SQLITE_PRIVATE char sqlite3ExprAffinity(const Expr *pExpr);
+SQLITE_PRIVATE int sqlite3ExprDataType(const Expr *pExpr);
+SQLITE_PRIVATE int sqlite3Atoi64(const char*, i64*, int, u8);
+SQLITE_PRIVATE int sqlite3DecOrHexToI64(const char*, i64*);
+SQLITE_PRIVATE void sqlite3ErrorWithMsg(sqlite3*, int, const char*,...);
+SQLITE_PRIVATE void sqlite3Error(sqlite3*,int);
+SQLITE_PRIVATE void sqlite3ErrorClear(sqlite3*);
+SQLITE_PRIVATE void sqlite3SystemError(sqlite3*,int);
+#if !defined(SQLITE_OMIT_BLOB_LITERAL)
+SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3*, const char *z, int n);
+#endif
+SQLITE_PRIVATE u8 sqlite3HexToInt(int h);
+SQLITE_PRIVATE int sqlite3TwoPartName(Parse *, Token *, Token *, Token **);
+
+#if defined(SQLITE_NEED_ERR_NAME)
+SQLITE_PRIVATE const char *sqlite3ErrName(int);
+#endif
+
+#ifndef SQLITE_OMIT_DESERIALIZE
+SQLITE_PRIVATE int sqlite3MemdbInit(void);
+SQLITE_PRIVATE int sqlite3IsMemdb(const sqlite3_vfs*);
+#else
+# define sqlite3IsMemdb(X) 0
+#endif
+
+SQLITE_PRIVATE const char *sqlite3ErrStr(int);
+SQLITE_PRIVATE int sqlite3ReadSchema(Parse *pParse);
+SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(sqlite3*,u8 enc, const char*,int);
+SQLITE_PRIVATE int sqlite3IsBinary(const CollSeq*);
+SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char*zName);
+SQLITE_PRIVATE void sqlite3SetTextEncoding(sqlite3 *db, u8);
+SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, const Expr *pExpr);
+SQLITE_PRIVATE CollSeq *sqlite3ExprNNCollSeq(Parse *pParse, const Expr *pExpr);
+SQLITE_PRIVATE int sqlite3ExprCollSeqMatch(Parse*,const Expr*,const Expr*);
+SQLITE_PRIVATE Expr *sqlite3ExprAddCollateToken(const Parse *pParse, Expr*, const Token*, int);
+SQLITE_PRIVATE Expr *sqlite3ExprAddCollateString(const Parse*,Expr*,const char*);
+SQLITE_PRIVATE Expr *sqlite3ExprSkipCollate(Expr*);
+SQLITE_PRIVATE Expr *sqlite3ExprSkipCollateAndLikely(Expr*);
+SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *, CollSeq *);
+SQLITE_PRIVATE int sqlite3WritableSchema(sqlite3*);
+SQLITE_PRIVATE int sqlite3CheckObjectName(Parse*, const char*,const char*,const char*);
+SQLITE_PRIVATE void sqlite3VdbeSetChanges(sqlite3 *, i64);
+SQLITE_PRIVATE int sqlite3AddInt64(i64*,i64);
+SQLITE_PRIVATE int sqlite3SubInt64(i64*,i64);
+SQLITE_PRIVATE int sqlite3MulInt64(i64*,i64);
+SQLITE_PRIVATE int sqlite3AbsInt32(int);
+#ifdef SQLITE_ENABLE_8_3_NAMES
+SQLITE_PRIVATE void sqlite3FileSuffix3(const char*, char*);
+#else
+# define sqlite3FileSuffix3(X,Y)
+#endif
+SQLITE_PRIVATE u8 sqlite3GetBoolean(const char *z,u8);
+
+SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value*, u8);
+SQLITE_PRIVATE int sqlite3ValueIsOfClass(const sqlite3_value*, void(*)(void*));
+SQLITE_PRIVATE int sqlite3ValueBytes(sqlite3_value*, u8);
+SQLITE_PRIVATE void sqlite3ValueSetStr(sqlite3_value*, int, const void *,u8,
+                        void(*)(void*));
+SQLITE_PRIVATE void sqlite3ValueSetNull(sqlite3_value*);
+SQLITE_PRIVATE void sqlite3ValueFree(sqlite3_value*);
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE void sqlite3ResultIntReal(sqlite3_context*);
+#endif
+SQLITE_PRIVATE sqlite3_value *sqlite3ValueNew(sqlite3 *);
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *, const void*, int, u8);
+#endif
+SQLITE_PRIVATE int sqlite3ValueFromExpr(sqlite3 *, const Expr *, u8, u8, sqlite3_value **);
+SQLITE_PRIVATE void sqlite3ValueApplyAffinity(sqlite3_value *, u8, u8);
+#ifndef SQLITE_AMALGAMATION
+SQLITE_PRIVATE const unsigned char sqlite3OpcodeProperty[];
+SQLITE_PRIVATE const char sqlite3StrBINARY[];
+SQLITE_PRIVATE const unsigned char sqlite3StdTypeLen[];
+SQLITE_PRIVATE const char sqlite3StdTypeAffinity[];
+SQLITE_PRIVATE const char *sqlite3StdType[];
+SQLITE_PRIVATE const unsigned char sqlite3UpperToLower[];
+SQLITE_PRIVATE const unsigned char *sqlite3aLTb;
+SQLITE_PRIVATE const unsigned char *sqlite3aEQb;
+SQLITE_PRIVATE const unsigned char *sqlite3aGTb;
+SQLITE_PRIVATE const unsigned char sqlite3CtypeMap[];
+SQLITE_PRIVATE SQLITE_WSD struct Sqlite3Config sqlite3Config;
+SQLITE_PRIVATE FuncDefHash sqlite3BuiltinFunctions;
+#ifndef SQLITE_OMIT_WSD
+SQLITE_PRIVATE int sqlite3PendingByte;
+#endif
+#endif /* SQLITE_AMALGAMATION */
+#ifdef VDBE_PROFILE
+SQLITE_PRIVATE sqlite3_uint64 sqlite3NProfileCnt;
+#endif
+SQLITE_PRIVATE void sqlite3RootPageMoved(sqlite3*, int, Pgno, Pgno);
+SQLITE_PRIVATE void sqlite3Reindex(Parse*, Token*, Token*);
+SQLITE_PRIVATE void sqlite3AlterFunctions(void);
+SQLITE_PRIVATE void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
+SQLITE_PRIVATE void sqlite3AlterRenameColumn(Parse*, SrcList*, Token*, Token*);
+SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *, int *);
+SQLITE_PRIVATE void sqlite3NestedParse(Parse*, const char*, ...);
+SQLITE_PRIVATE void sqlite3ExpirePreparedStatements(sqlite3*, int);
+SQLITE_PRIVATE void sqlite3CodeRhsOfIN(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3CodeSubselect(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3SelectPrep(Parse*, Select*, NameContext*);
+SQLITE_PRIVATE int sqlite3ExpandSubquery(Parse*, SrcItem*);
+SQLITE_PRIVATE void sqlite3SelectWrongNumTermsError(Parse *pParse, Select *p);
+SQLITE_PRIVATE int sqlite3MatchEName(
+  const struct ExprList_item*,
+  const char*,
+  const char*,
+  const char*,
+  int*
+);
+SQLITE_PRIVATE Bitmask sqlite3ExprColUsed(Expr*);
+SQLITE_PRIVATE u8 sqlite3StrIHash(const char*);
+SQLITE_PRIVATE int sqlite3ResolveExprNames(NameContext*, Expr*);
+SQLITE_PRIVATE int sqlite3ResolveExprListNames(NameContext*, ExprList*);
+SQLITE_PRIVATE void sqlite3ResolveSelectNames(Parse*, Select*, NameContext*);
+SQLITE_PRIVATE int sqlite3ResolveSelfReference(Parse*,Table*,int,Expr*,ExprList*);
+SQLITE_PRIVATE int sqlite3ResolveOrderGroupBy(Parse*, Select*, ExprList*, const char*);
+SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *, Table *, int, int);
+SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *, Token *);
+SQLITE_PRIVATE void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
+SQLITE_PRIVATE void sqlite3AlterDropColumn(Parse*, SrcList*, const Token*);
+SQLITE_PRIVATE const void *sqlite3RenameTokenMap(Parse*, const void*, const Token*);
+SQLITE_PRIVATE void sqlite3RenameTokenRemap(Parse*, const void *pTo, const void *pFrom);
+SQLITE_PRIVATE void sqlite3RenameExprUnmap(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3RenameExprlistUnmap(Parse*, ExprList*);
+SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(Parse*, u8, CollSeq *, const char*);
+SQLITE_PRIVATE char sqlite3AffinityType(const char*, Column*);
+SQLITE_PRIVATE void sqlite3Analyze(Parse*, Token*, Token*);
+SQLITE_PRIVATE int sqlite3InvokeBusyHandler(BusyHandler*);
+SQLITE_PRIVATE int sqlite3FindDb(sqlite3*, Token*);
+SQLITE_PRIVATE int sqlite3FindDbName(sqlite3 *, const char *);
+SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3*,int iDB);
+SQLITE_PRIVATE void sqlite3DeleteIndexSamples(sqlite3*,Index*);
+SQLITE_PRIVATE void sqlite3DefaultRowEst(Index*);
+SQLITE_PRIVATE void sqlite3RegisterLikeFunctions(sqlite3*, int);
+SQLITE_PRIVATE int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
+SQLITE_PRIVATE void sqlite3SchemaClear(void *);
+SQLITE_PRIVATE Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
+SQLITE_PRIVATE int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoAlloc(sqlite3*,int,int);
+SQLITE_PRIVATE void sqlite3KeyInfoUnref(KeyInfo*);
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoRef(KeyInfo*);
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoOfIndex(Parse*, Index*);
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoFromExprList(Parse*, ExprList*, int, int);
+SQLITE_PRIVATE const char *sqlite3SelectOpName(int);
+SQLITE_PRIVATE int sqlite3HasExplicitNulls(Parse*, ExprList*);
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3KeyInfoIsWriteable(KeyInfo*);
+#endif
+SQLITE_PRIVATE int sqlite3CreateFunc(sqlite3 *, const char *, int, int, void *,
+  void (*)(sqlite3_context*,int,sqlite3_value **),
+  void (*)(sqlite3_context*,int,sqlite3_value **),
+  void (*)(sqlite3_context*),
+  void (*)(sqlite3_context*),
+  void (*)(sqlite3_context*,int,sqlite3_value **),
+  FuncDestructor *pDestructor
+);
+SQLITE_PRIVATE void sqlite3NoopDestructor(void*);
+SQLITE_PRIVATE void *sqlite3OomFault(sqlite3*);
+SQLITE_PRIVATE void sqlite3OomClear(sqlite3*);
+SQLITE_PRIVATE int sqlite3ApiExit(sqlite3 *db, int);
+SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *);
+
+SQLITE_PRIVATE char *sqlite3RCStrRef(char*);
+SQLITE_PRIVATE void sqlite3RCStrUnref(void*);
+SQLITE_PRIVATE char *sqlite3RCStrNew(u64);
+SQLITE_PRIVATE char *sqlite3RCStrResize(char*,u64);
+
+SQLITE_PRIVATE void sqlite3StrAccumInit(StrAccum*, sqlite3*, char*, int, int);
+SQLITE_PRIVATE int sqlite3StrAccumEnlarge(StrAccum*, i64);
+SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum*);
+SQLITE_PRIVATE void sqlite3StrAccumSetError(StrAccum*, u8);
+SQLITE_PRIVATE void sqlite3ResultStrAccum(sqlite3_context*,StrAccum*);
+SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest*,int,int);
+SQLITE_PRIVATE Expr *sqlite3CreateColumnExpr(sqlite3 *, SrcList *, int, int);
+SQLITE_PRIVATE void sqlite3RecordErrorByteOffset(sqlite3*,const char*);
+SQLITE_PRIVATE void sqlite3RecordErrorOffsetOfExpr(sqlite3*,const Expr*);
+
+SQLITE_PRIVATE void sqlite3BackupRestart(sqlite3_backup *);
+SQLITE_PRIVATE void sqlite3BackupUpdate(sqlite3_backup *, Pgno, const u8 *);
+
+#ifndef SQLITE_OMIT_SUBQUERY
+SQLITE_PRIVATE int sqlite3ExprCheckIN(Parse*, Expr*);
+#else
+# define sqlite3ExprCheckIN(x,y) SQLITE_OK
+#endif
+
+#ifdef SQLITE_ENABLE_STAT4
+SQLITE_PRIVATE int sqlite3Stat4ProbeSetValue(
+    Parse*,Index*,UnpackedRecord**,Expr*,int,int,int*);
+SQLITE_PRIVATE int sqlite3Stat4ValueFromExpr(Parse*, Expr*, u8, sqlite3_value**);
+SQLITE_PRIVATE void sqlite3Stat4ProbeFree(UnpackedRecord*);
+SQLITE_PRIVATE int sqlite3Stat4Column(sqlite3*, const void*, int, int, sqlite3_value**);
+SQLITE_PRIVATE char sqlite3IndexColumnAffinity(sqlite3*, Index*, int);
+#endif
+
+/*
+** The interface to the LEMON-generated parser
+*/
+#ifndef SQLITE_AMALGAMATION
+SQLITE_PRIVATE   void *sqlite3ParserAlloc(void*(*)(u64), Parse*);
+SQLITE_PRIVATE   void sqlite3ParserFree(void*, void(*)(void*));
+#endif
+SQLITE_PRIVATE void sqlite3Parser(void*, int, Token);
+SQLITE_PRIVATE int sqlite3ParserFallback(int);
+#ifdef YYTRACKMAXSTACKDEPTH
+SQLITE_PRIVATE   int sqlite3ParserStackPeak(void*);
+#endif
+
+SQLITE_PRIVATE void sqlite3AutoLoadExtensions(sqlite3*);
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+SQLITE_PRIVATE   void sqlite3CloseExtensions(sqlite3*);
+#else
+# define sqlite3CloseExtensions(X)
+#endif
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+SQLITE_PRIVATE   void sqlite3TableLock(Parse *, int, Pgno, u8, const char *);
+#else
+  #define sqlite3TableLock(v,w,x,y,z)
+#endif
+
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE   int sqlite3Utf8To8(unsigned char*);
+#endif
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+#  define sqlite3VtabClear(D,T)
+#  define sqlite3VtabSync(X,Y) SQLITE_OK
+#  define sqlite3VtabRollback(X)
+#  define sqlite3VtabCommit(X)
+#  define sqlite3VtabInSync(db) 0
+#  define sqlite3VtabLock(X)
+#  define sqlite3VtabUnlock(X)
+#  define sqlite3VtabModuleUnref(D,X)
+#  define sqlite3VtabUnlockList(X)
+#  define sqlite3VtabSavepoint(X, Y, Z) SQLITE_OK
+#  define sqlite3GetVTable(X,Y)  ((VTable*)0)
+#else
+SQLITE_PRIVATE    void sqlite3VtabClear(sqlite3 *db, Table*);
+SQLITE_PRIVATE    void sqlite3VtabDisconnect(sqlite3 *db, Table *p);
+SQLITE_PRIVATE    int sqlite3VtabSync(sqlite3 *db, Vdbe*);
+SQLITE_PRIVATE    int sqlite3VtabRollback(sqlite3 *db);
+SQLITE_PRIVATE    int sqlite3VtabCommit(sqlite3 *db);
+SQLITE_PRIVATE    void sqlite3VtabLock(VTable *);
+SQLITE_PRIVATE    void sqlite3VtabUnlock(VTable *);
+SQLITE_PRIVATE    void sqlite3VtabModuleUnref(sqlite3*,Module*);
+SQLITE_PRIVATE    void sqlite3VtabUnlockList(sqlite3*);
+SQLITE_PRIVATE    int sqlite3VtabSavepoint(sqlite3 *, int, int);
+SQLITE_PRIVATE    void sqlite3VtabImportErrmsg(Vdbe*, sqlite3_vtab*);
+SQLITE_PRIVATE    VTable *sqlite3GetVTable(sqlite3*, Table*);
+SQLITE_PRIVATE    Module *sqlite3VtabCreateModule(
+     sqlite3*,
+     const char*,
+     const sqlite3_module*,
+     void*,
+     void(*)(void*)
+   );
+#  define sqlite3VtabInSync(db) ((db)->nVTrans>0 && (db)->aVTrans==0)
+#endif
+SQLITE_PRIVATE int sqlite3ReadOnlyShadowTables(sqlite3 *db);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+SQLITE_PRIVATE   int sqlite3ShadowTableName(sqlite3 *db, const char *zName);
+SQLITE_PRIVATE   int sqlite3IsShadowTableOf(sqlite3*,Table*,const char*);
+SQLITE_PRIVATE   void sqlite3MarkAllShadowTablesOf(sqlite3*, Table*);
+#else
+# define sqlite3ShadowTableName(A,B) 0
+# define sqlite3IsShadowTableOf(A,B,C) 0
+# define sqlite3MarkAllShadowTablesOf(A,B)
+#endif
+SQLITE_PRIVATE int sqlite3VtabEponymousTableInit(Parse*,Module*);
+SQLITE_PRIVATE void sqlite3VtabEponymousTableClear(sqlite3*,Module*);
+SQLITE_PRIVATE void sqlite3VtabMakeWritable(Parse*,Table*);
+SQLITE_PRIVATE void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*, int);
+SQLITE_PRIVATE void sqlite3VtabFinishParse(Parse*, Token*);
+SQLITE_PRIVATE void sqlite3VtabArgInit(Parse*);
+SQLITE_PRIVATE void sqlite3VtabArgExtend(Parse*, Token*);
+SQLITE_PRIVATE int sqlite3VtabCallCreate(sqlite3*, int, const char *, char **);
+SQLITE_PRIVATE int sqlite3VtabCallConnect(Parse*, Table*);
+SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3*, int, const char *);
+SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *, VTable *);
+
+SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
+SQLITE_PRIVATE void sqlite3VtabUsesAllSchemas(Parse*);
+SQLITE_PRIVATE sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context*);
+SQLITE_PRIVATE int sqlite3VdbeParameterIndex(Vdbe*, const char*, int);
+SQLITE_PRIVATE int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
+SQLITE_PRIVATE void sqlite3ParseObjectInit(Parse*,sqlite3*);
+SQLITE_PRIVATE void sqlite3ParseObjectReset(Parse*);
+SQLITE_PRIVATE void *sqlite3ParserAddCleanup(Parse*,void(*)(sqlite3*,void*),void*);
+#ifdef SQLITE_ENABLE_NORMALIZE
+SQLITE_PRIVATE char *sqlite3Normalize(Vdbe*, const char*);
+#endif
+SQLITE_PRIVATE int sqlite3Reprepare(Vdbe*);
+SQLITE_PRIVATE void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
+SQLITE_PRIVATE CollSeq *sqlite3ExprCompareCollSeq(Parse*,const Expr*);
+SQLITE_PRIVATE CollSeq *sqlite3BinaryCompareCollSeq(Parse *, const Expr*, const Expr*);
+SQLITE_PRIVATE int sqlite3TempInMemory(const sqlite3*);
+SQLITE_PRIVATE const char *sqlite3JournalModename(int);
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE   int sqlite3Checkpoint(sqlite3*, int, int, int*, int*);
+SQLITE_PRIVATE   int sqlite3WalDefaultHook(void*,sqlite3*,const char*,int);
+#endif
+#ifndef SQLITE_OMIT_CTE
+SQLITE_PRIVATE   Cte *sqlite3CteNew(Parse*,Token*,ExprList*,Select*,u8);
+SQLITE_PRIVATE   void sqlite3CteDelete(sqlite3*,Cte*);
+SQLITE_PRIVATE   With *sqlite3WithAdd(Parse*,With*,Cte*);
+SQLITE_PRIVATE   void sqlite3WithDelete(sqlite3*,With*);
+SQLITE_PRIVATE   void sqlite3WithDeleteGeneric(sqlite3*,void*);
+SQLITE_PRIVATE   With *sqlite3WithPush(Parse*, With*, u8);
+#else
+# define sqlite3CteNew(P,T,E,S)   ((void*)0)
+# define sqlite3CteDelete(D,C)
+# define sqlite3CteWithAdd(P,W,C) ((void*)0)
+# define sqlite3WithDelete(x,y)
+# define sqlite3WithPush(x,y,z) ((void*)0)
+#endif
+#ifndef SQLITE_OMIT_UPSERT
+SQLITE_PRIVATE   Upsert *sqlite3UpsertNew(sqlite3*,ExprList*,Expr*,ExprList*,Expr*,Upsert*);
+SQLITE_PRIVATE   void sqlite3UpsertDelete(sqlite3*,Upsert*);
+SQLITE_PRIVATE   Upsert *sqlite3UpsertDup(sqlite3*,Upsert*);
+SQLITE_PRIVATE   int sqlite3UpsertAnalyzeTarget(Parse*,SrcList*,Upsert*,Upsert*);
+SQLITE_PRIVATE   void sqlite3UpsertDoUpdate(Parse*,Upsert*,Table*,Index*,int);
+SQLITE_PRIVATE   Upsert *sqlite3UpsertOfIndex(Upsert*,Index*);
+SQLITE_PRIVATE   int sqlite3UpsertNextIsIPK(Upsert*);
+#else
+#define sqlite3UpsertNew(u,v,w,x,y,z) ((Upsert*)0)
+#define sqlite3UpsertDelete(x,y)
+#define sqlite3UpsertDup(x,y)         ((Upsert*)0)
+#define sqlite3UpsertOfIndex(x,y)     ((Upsert*)0)
+#define sqlite3UpsertNextIsIPK(x)     0
+#endif
+
+
+/* Declarations for functions in fkey.c. All of these are replaced by
+** no-op macros if OMIT_FOREIGN_KEY is defined. In this case no foreign
+** key functionality is available. If OMIT_TRIGGER is defined but
+** OMIT_FOREIGN_KEY is not, only some of the functions are no-oped. In
+** this case foreign keys are parsed, but no other functionality is
+** provided (enforcement of FK constraints requires the triggers sub-system).
+*/
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+SQLITE_PRIVATE   void sqlite3FkCheck(Parse*, Table*, int, int, int*, int);
+SQLITE_PRIVATE   void sqlite3FkDropTable(Parse*, SrcList *, Table*);
+SQLITE_PRIVATE   void sqlite3FkActions(Parse*, Table*, ExprList*, int, int*, int);
+SQLITE_PRIVATE   int sqlite3FkRequired(Parse*, Table*, int*, int);
+SQLITE_PRIVATE   u32 sqlite3FkOldmask(Parse*, Table*);
+SQLITE_PRIVATE   FKey *sqlite3FkReferences(Table *);
+SQLITE_PRIVATE   void sqlite3FkClearTriggerCache(sqlite3*,int);
+#else
+  #define sqlite3FkActions(a,b,c,d,e,f)
+  #define sqlite3FkCheck(a,b,c,d,e,f)
+  #define sqlite3FkDropTable(a,b,c)
+  #define sqlite3FkOldmask(a,b)         0
+  #define sqlite3FkRequired(a,b,c,d)    0
+  #define sqlite3FkReferences(a)        0
+  #define sqlite3FkClearTriggerCache(a,b)
+#endif
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+SQLITE_PRIVATE   void sqlite3FkDelete(sqlite3 *, Table*);
+SQLITE_PRIVATE   int sqlite3FkLocateIndex(Parse*,Table*,FKey*,Index**,int**);
+#else
+  #define sqlite3FkDelete(a,b)
+  #define sqlite3FkLocateIndex(a,b,c,d,e)
+#endif
+
+
+/*
+** Available fault injectors.  Should be numbered beginning with 0.
+*/
+#define SQLITE_FAULTINJECTOR_MALLOC     0
+#define SQLITE_FAULTINJECTOR_COUNT      1
+
+/*
+** The interface to the code in fault.c used for identifying "benign"
+** malloc failures. This is only present if SQLITE_UNTESTABLE
+** is not defined.
+*/
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE   void sqlite3BeginBenignMalloc(void);
+SQLITE_PRIVATE   void sqlite3EndBenignMalloc(void);
+#else
+  #define sqlite3BeginBenignMalloc()
+  #define sqlite3EndBenignMalloc()
+#endif
+
+/*
+** Allowed return values from sqlite3FindInIndex()
+*/
+#define IN_INDEX_ROWID        1   /* Search the rowid of the table */
+#define IN_INDEX_EPH          2   /* Search an ephemeral b-tree */
+#define IN_INDEX_INDEX_ASC    3   /* Existing index ASCENDING */
+#define IN_INDEX_INDEX_DESC   4   /* Existing index DESCENDING */
+#define IN_INDEX_NOOP         5   /* No table available. Use comparisons */
+/*
+** Allowed flags for the 3rd parameter to sqlite3FindInIndex().
+*/
+#define IN_INDEX_NOOP_OK     0x0001  /* OK to return IN_INDEX_NOOP */
+#define IN_INDEX_MEMBERSHIP  0x0002  /* IN operator used for membership test */
+#define IN_INDEX_LOOP        0x0004  /* IN operator used as a loop */
+SQLITE_PRIVATE int sqlite3FindInIndex(Parse *, Expr *, u32, int*, int*, int*);
+
+SQLITE_PRIVATE int sqlite3JournalOpen(sqlite3_vfs *, const char *, sqlite3_file *, int, int);
+SQLITE_PRIVATE int sqlite3JournalSize(sqlite3_vfs *);
+#if defined(SQLITE_ENABLE_ATOMIC_WRITE) \
+ || defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+SQLITE_PRIVATE   int sqlite3JournalCreate(sqlite3_file *);
+#endif
+
+SQLITE_PRIVATE int sqlite3JournalIsInMemory(sqlite3_file *p);
+SQLITE_PRIVATE void sqlite3MemJournalOpen(sqlite3_file *);
+
+SQLITE_PRIVATE void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p);
+#if SQLITE_MAX_EXPR_DEPTH>0
+SQLITE_PRIVATE   int sqlite3SelectExprHeight(const Select *);
+SQLITE_PRIVATE   int sqlite3ExprCheckHeight(Parse*, int);
+#else
+  #define sqlite3SelectExprHeight(x) 0
+  #define sqlite3ExprCheckHeight(x,y)
+#endif
+SQLITE_PRIVATE void sqlite3ExprSetErrorOffset(Expr*,int);
+
+SQLITE_PRIVATE u32 sqlite3Get4byte(const u8*);
+SQLITE_PRIVATE void sqlite3Put4byte(u8*, u32);
+
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+SQLITE_PRIVATE   void sqlite3ConnectionBlocked(sqlite3 *, sqlite3 *);
+SQLITE_PRIVATE   void sqlite3ConnectionUnlocked(sqlite3 *db);
+SQLITE_PRIVATE   void sqlite3ConnectionClosed(sqlite3 *db);
+#else
+  #define sqlite3ConnectionBlocked(x,y)
+  #define sqlite3ConnectionUnlocked(x)
+  #define sqlite3ConnectionClosed(x)
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3ParserTrace(FILE*, char *);
+#endif
+#if defined(YYCOVERAGE)
+SQLITE_PRIVATE   int sqlite3ParserCoverage(FILE*);
+#endif
+
+/*
+** If the SQLITE_ENABLE IOTRACE exists then the global variable
+** sqlite3IoTrace is a pointer to a printf-like routine used to
+** print I/O tracing messages.
+*/
+#ifdef SQLITE_ENABLE_IOTRACE
+# define IOTRACE(A)  if( sqlite3IoTrace ){ sqlite3IoTrace A; }
+SQLITE_PRIVATE   void sqlite3VdbeIOTraceSql(Vdbe*);
+SQLITE_API SQLITE_EXTERN void (SQLITE_CDECL *sqlite3IoTrace)(const char*,...);
+#else
+# define IOTRACE(A)
+# define sqlite3VdbeIOTraceSql(X)
+#endif
+
+/*
+** These routines are available for the mem2.c debugging memory allocator
+** only.  They are used to verify that different "types" of memory
+** allocations are properly tracked by the system.
+**
+** sqlite3MemdebugSetType() sets the "type" of an allocation to one of
+** the MEMTYPE_* macros defined below.  The type must be a bitmask with
+** a single bit set.
+**
+** sqlite3MemdebugHasType() returns true if any of the bits in its second
+** argument match the type set by the previous sqlite3MemdebugSetType().
+** sqlite3MemdebugHasType() is intended for use inside assert() statements.
+**
+** sqlite3MemdebugNoType() returns true if none of the bits in its second
+** argument match the type set by the previous sqlite3MemdebugSetType().
+**
+** Perhaps the most important point is the difference between MEMTYPE_HEAP
+** and MEMTYPE_LOOKASIDE.  If an allocation is MEMTYPE_LOOKASIDE, that means
+** it might have been allocated by lookaside, except the allocation was
+** too large or lookaside was already full.  It is important to verify
+** that allocations that might have been satisfied by lookaside are not
+** passed back to non-lookaside free() routines.  Asserts such as the
+** example above are placed on the non-lookaside free() routines to verify
+** this constraint.
+**
+** All of this is no-op for a production build.  It only comes into
+** play when the SQLITE_MEMDEBUG compile-time option is used.
+*/
+#ifdef SQLITE_MEMDEBUG
+SQLITE_PRIVATE   void sqlite3MemdebugSetType(void*,u8);
+SQLITE_PRIVATE   int sqlite3MemdebugHasType(const void*,u8);
+SQLITE_PRIVATE   int sqlite3MemdebugNoType(const void*,u8);
+#else
+# define sqlite3MemdebugSetType(X,Y)  /* no-op */
+# define sqlite3MemdebugHasType(X,Y)  1
+# define sqlite3MemdebugNoType(X,Y)   1
+#endif
+#define MEMTYPE_HEAP       0x01  /* General heap allocations */
+#define MEMTYPE_LOOKASIDE  0x02  /* Heap that might have been lookaside */
+#define MEMTYPE_PCACHE     0x04  /* Page cache allocations */
+
+/*
+** Threading interface
+*/
+#if SQLITE_MAX_WORKER_THREADS>0
+SQLITE_PRIVATE int sqlite3ThreadCreate(SQLiteThread**,void*(*)(void*),void*);
+SQLITE_PRIVATE int sqlite3ThreadJoin(SQLiteThread*, void**);
+#endif
+
+#if defined(SQLITE_ENABLE_DBPAGE_VTAB) || defined(SQLITE_TEST)
+SQLITE_PRIVATE int sqlite3DbpageRegister(sqlite3*);
+#endif
+#if defined(SQLITE_ENABLE_DBSTAT_VTAB) || defined(SQLITE_TEST)
+SQLITE_PRIVATE int sqlite3DbstatRegister(sqlite3*);
+#endif
+
+SQLITE_PRIVATE int sqlite3ExprVectorSize(const Expr *pExpr);
+SQLITE_PRIVATE int sqlite3ExprIsVector(const Expr *pExpr);
+SQLITE_PRIVATE Expr *sqlite3VectorFieldSubexpr(Expr*, int);
+SQLITE_PRIVATE Expr *sqlite3ExprForVectorField(Parse*,Expr*,int,int);
+SQLITE_PRIVATE void sqlite3VectorErrorMsg(Parse*, Expr*);
+
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+SQLITE_PRIVATE const char **sqlite3CompileOptions(int *pnOpt);
+#endif
+
+#if SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL)
+SQLITE_PRIVATE int sqlite3KvvfsInit(void);
+#endif
+
+#if defined(VDBE_PROFILE) \
+ || defined(SQLITE_PERFORMANCE_TRACE) \
+ || defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+SQLITE_PRIVATE sqlite3_uint64 sqlite3Hwtime(void);
+#endif
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+# define IS_STMT_SCANSTATUS(db) (db->flags & SQLITE_StmtScanStatus)
+#else
+# define IS_STMT_SCANSTATUS(db) 0
+#endif
+
+#endif /* SQLITEINT_H */
+
+/************** End of sqliteInt.h *******************************************/
+/************** Begin file os_common.h ***************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains macros and a little bit of code that is common to
+** all of the platform-specific files (os_*.c) and is #included into those
+** files.
+**
+** This file should be #included by the os_*.c files only.  It is not a
+** general purpose header file.
+*/
+#ifndef _OS_COMMON_H_
+#define _OS_COMMON_H_
+
+/*
+** At least two bugs have slipped in because we changed the MEMORY_DEBUG
+** macro to SQLITE_DEBUG and some older makefiles have not yet made the
+** switch.  The following code should catch this problem at compile-time.
+*/
+#ifdef MEMORY_DEBUG
+# error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
+#endif
+
+/*
+** Macros for performance tracing.  Normally turned off.  Only works
+** on i486 hardware.
+*/
+#ifdef SQLITE_PERFORMANCE_TRACE
+
+static sqlite_uint64 g_start;
+static sqlite_uint64 g_elapsed;
+#define TIMER_START       g_start=sqlite3Hwtime()
+#define TIMER_END         g_elapsed=sqlite3Hwtime()-g_start
+#define TIMER_ELAPSED     g_elapsed
+#else
+#define TIMER_START
+#define TIMER_END
+#define TIMER_ELAPSED     ((sqlite_uint64)0)
+#endif
+
+/*
+** If we compile with the SQLITE_TEST macro set, then the following block
+** of code will give us the ability to simulate a disk I/O error.  This
+** is used for testing the I/O recovery logic.
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API extern int sqlite3_io_error_hit;
+SQLITE_API extern int sqlite3_io_error_hardhit;
+SQLITE_API extern int sqlite3_io_error_pending;
+SQLITE_API extern int sqlite3_io_error_persist;
+SQLITE_API extern int sqlite3_io_error_benign;
+SQLITE_API extern int sqlite3_diskfull_pending;
+SQLITE_API extern int sqlite3_diskfull;
+#define SimulateIOErrorBenign(X) sqlite3_io_error_benign=(X)
+#define SimulateIOError(CODE)  \
+  if( (sqlite3_io_error_persist && sqlite3_io_error_hit) \
+       || sqlite3_io_error_pending-- == 1 )  \
+              { local_ioerr(); CODE; }
+static void local_ioerr(){
+  IOTRACE(("IOERR\n"));
+  sqlite3_io_error_hit++;
+  if( !sqlite3_io_error_benign ) sqlite3_io_error_hardhit++;
+}
+#define SimulateDiskfullError(CODE) \
+   if( sqlite3_diskfull_pending ){ \
+     if( sqlite3_diskfull_pending == 1 ){ \
+       local_ioerr(); \
+       sqlite3_diskfull = 1; \
+       sqlite3_io_error_hit = 1; \
+       CODE; \
+     }else{ \
+       sqlite3_diskfull_pending--; \
+     } \
+   }
+#else
+#define SimulateIOErrorBenign(X)
+#define SimulateIOError(A)
+#define SimulateDiskfullError(A)
+#endif /* defined(SQLITE_TEST) */
+
+/*
+** When testing, keep a count of the number of open files.
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API extern int sqlite3_open_file_count;
+#define OpenCounter(X)  sqlite3_open_file_count+=(X)
+#else
+#define OpenCounter(X)
+#endif /* defined(SQLITE_TEST) */
+
+#endif /* !defined(_OS_COMMON_H_) */
+
+/************** End of os_common.h *******************************************/
+/************** Begin file ctime.c *******************************************/
+/* DO NOT EDIT!
+** This file is automatically generated by the script in the canonical
+** SQLite source tree at tool/mkctimec.tcl.
+**
+** To modify this header, edit any of the various lists in that script
+** which specify categories of generated conditionals in this file.
+*/
+
+/*
+** 2010 February 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements routines used to report what compile-time options
+** SQLite was built with.
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS /* IMP: R-16824-07538 */
+
+/*
+** Include the configuration header output by 'configure' if we're using the
+** autoconf-based build
+*/
+#if defined(_HAVE_SQLITE_CONFIG_H) && !defined(SQLITECONFIG_H)
+/* #include "sqlite_cfg.h" */
+#define SQLITECONFIG_H 1
+#endif
+
+/* These macros are provided to "stringify" the value of the define
+** for those options in which the value is meaningful. */
+#define CTIMEOPT_VAL_(opt) #opt
+#define CTIMEOPT_VAL(opt) CTIMEOPT_VAL_(opt)
+
+/* Like CTIMEOPT_VAL, but especially for SQLITE_DEFAULT_LOOKASIDE. This
+** option requires a separate macro because legal values contain a single
+** comma. e.g. (-DSQLITE_DEFAULT_LOOKASIDE="100,100") */
+#define CTIMEOPT_VAL2_(opt1,opt2) #opt1 "," #opt2
+#define CTIMEOPT_VAL2(opt) CTIMEOPT_VAL2_(opt)
+/* #include "sqliteInt.h" */
+
+/*
+** An array of names of all compile-time options.  This array should
+** be sorted A-Z.
+**
+** This array looks large, but in a typical installation actually uses
+** only a handful of compile-time options, so most times this array is usually
+** rather short and uses little memory space.
+*/
+static const char * const sqlite3azCompileOpt[] = {
+
+#ifdef SQLITE_32BIT_ROWID
+  "32BIT_ROWID",
+#endif
+#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
+  "4_BYTE_ALIGNED_MALLOC",
+#endif
+#ifdef SQLITE_ALLOW_COVERING_INDEX_SCAN
+# if SQLITE_ALLOW_COVERING_INDEX_SCAN != 1
+  "ALLOW_COVERING_INDEX_SCAN=" CTIMEOPT_VAL(SQLITE_ALLOW_COVERING_INDEX_SCAN),
+# endif
+#endif
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  "ALLOW_ROWID_IN_VIEW",
+#endif
+#ifdef SQLITE_ALLOW_URI_AUTHORITY
+  "ALLOW_URI_AUTHORITY",
+#endif
+#ifdef SQLITE_ATOMIC_INTRINSICS
+  "ATOMIC_INTRINSICS=" CTIMEOPT_VAL(SQLITE_ATOMIC_INTRINSICS),
+#endif
+#ifdef SQLITE_BITMASK_TYPE
+  "BITMASK_TYPE=" CTIMEOPT_VAL(SQLITE_BITMASK_TYPE),
+#endif
+#ifdef SQLITE_BUG_COMPATIBLE_20160819
+  "BUG_COMPATIBLE_20160819",
+#endif
+#ifdef SQLITE_CASE_SENSITIVE_LIKE
+  "CASE_SENSITIVE_LIKE",
+#endif
+#ifdef SQLITE_CHECK_PAGES
+  "CHECK_PAGES",
+#endif
+#if defined(__clang__) && defined(__clang_major__)
+  "COMPILER=clang-" CTIMEOPT_VAL(__clang_major__) "."
+                    CTIMEOPT_VAL(__clang_minor__) "."
+                    CTIMEOPT_VAL(__clang_patchlevel__),
+#elif defined(_MSC_VER)
+  "COMPILER=msvc-" CTIMEOPT_VAL(_MSC_VER),
+#elif defined(__GNUC__) && defined(__VERSION__)
+  "COMPILER=gcc-" __VERSION__,
+#endif
+#ifdef SQLITE_COVERAGE_TEST
+  "COVERAGE_TEST",
+#endif
+#ifdef SQLITE_DEBUG
+  "DEBUG",
+#endif
+#ifdef SQLITE_DEFAULT_AUTOMATIC_INDEX
+  "DEFAULT_AUTOMATIC_INDEX",
+#endif
+#ifdef SQLITE_DEFAULT_AUTOVACUUM
+  "DEFAULT_AUTOVACUUM",
+#endif
+#ifdef SQLITE_DEFAULT_CACHE_SIZE
+  "DEFAULT_CACHE_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_CACHE_SIZE),
+#endif
+#ifdef SQLITE_DEFAULT_CKPTFULLFSYNC
+  "DEFAULT_CKPTFULLFSYNC",
+#endif
+#ifdef SQLITE_DEFAULT_FILE_FORMAT
+  "DEFAULT_FILE_FORMAT=" CTIMEOPT_VAL(SQLITE_DEFAULT_FILE_FORMAT),
+#endif
+#ifdef SQLITE_DEFAULT_FILE_PERMISSIONS
+  "DEFAULT_FILE_PERMISSIONS=" CTIMEOPT_VAL(SQLITE_DEFAULT_FILE_PERMISSIONS),
+#endif
+#ifdef SQLITE_DEFAULT_FOREIGN_KEYS
+  "DEFAULT_FOREIGN_KEYS",
+#endif
+#ifdef SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT
+  "DEFAULT_JOURNAL_SIZE_LIMIT=" CTIMEOPT_VAL(SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT),
+#endif
+#ifdef SQLITE_DEFAULT_LOCKING_MODE
+  "DEFAULT_LOCKING_MODE=" CTIMEOPT_VAL(SQLITE_DEFAULT_LOCKING_MODE),
+#endif
+#ifdef SQLITE_DEFAULT_LOOKASIDE
+  "DEFAULT_LOOKASIDE=" CTIMEOPT_VAL2(SQLITE_DEFAULT_LOOKASIDE),
+#endif
+#ifdef SQLITE_DEFAULT_MEMSTATUS
+# if SQLITE_DEFAULT_MEMSTATUS != 1
+  "DEFAULT_MEMSTATUS=" CTIMEOPT_VAL(SQLITE_DEFAULT_MEMSTATUS),
+# endif
+#endif
+#ifdef SQLITE_DEFAULT_MMAP_SIZE
+  "DEFAULT_MMAP_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_MMAP_SIZE),
+#endif
+#ifdef SQLITE_DEFAULT_PAGE_SIZE
+  "DEFAULT_PAGE_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_PAGE_SIZE),
+#endif
+#ifdef SQLITE_DEFAULT_PCACHE_INITSZ
+  "DEFAULT_PCACHE_INITSZ=" CTIMEOPT_VAL(SQLITE_DEFAULT_PCACHE_INITSZ),
+#endif
+#ifdef SQLITE_DEFAULT_PROXYDIR_PERMISSIONS
+  "DEFAULT_PROXYDIR_PERMISSIONS=" CTIMEOPT_VAL(SQLITE_DEFAULT_PROXYDIR_PERMISSIONS),
+#endif
+#ifdef SQLITE_DEFAULT_RECURSIVE_TRIGGERS
+  "DEFAULT_RECURSIVE_TRIGGERS",
+#endif
+#ifdef SQLITE_DEFAULT_ROWEST
+  "DEFAULT_ROWEST=" CTIMEOPT_VAL(SQLITE_DEFAULT_ROWEST),
+#endif
+#ifdef SQLITE_DEFAULT_SECTOR_SIZE
+  "DEFAULT_SECTOR_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_SECTOR_SIZE),
+#endif
+#ifdef SQLITE_DEFAULT_SYNCHRONOUS
+  "DEFAULT_SYNCHRONOUS=" CTIMEOPT_VAL(SQLITE_DEFAULT_SYNCHRONOUS),
+#endif
+#ifdef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT
+  "DEFAULT_WAL_AUTOCHECKPOINT=" CTIMEOPT_VAL(SQLITE_DEFAULT_WAL_AUTOCHECKPOINT),
+#endif
+#ifdef SQLITE_DEFAULT_WAL_SYNCHRONOUS
+  "DEFAULT_WAL_SYNCHRONOUS=" CTIMEOPT_VAL(SQLITE_DEFAULT_WAL_SYNCHRONOUS),
+#endif
+#ifdef SQLITE_DEFAULT_WORKER_THREADS
+  "DEFAULT_WORKER_THREADS=" CTIMEOPT_VAL(SQLITE_DEFAULT_WORKER_THREADS),
+#endif
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+  "DIRECT_OVERFLOW_READ",
+#endif
+#ifdef SQLITE_DISABLE_DIRSYNC
+  "DISABLE_DIRSYNC",
+#endif
+#ifdef SQLITE_DISABLE_FTS3_UNICODE
+  "DISABLE_FTS3_UNICODE",
+#endif
+#ifdef SQLITE_DISABLE_FTS4_DEFERRED
+  "DISABLE_FTS4_DEFERRED",
+#endif
+#ifdef SQLITE_DISABLE_INTRINSIC
+  "DISABLE_INTRINSIC",
+#endif
+#ifdef SQLITE_DISABLE_LFS
+  "DISABLE_LFS",
+#endif
+#ifdef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
+  "DISABLE_PAGECACHE_OVERFLOW_STATS",
+#endif
+#ifdef SQLITE_DISABLE_SKIPAHEAD_DISTINCT
+  "DISABLE_SKIPAHEAD_DISTINCT",
+#endif
+#ifdef SQLITE_DQS
+  "DQS=" CTIMEOPT_VAL(SQLITE_DQS),
+#endif
+#ifdef SQLITE_ENABLE_8_3_NAMES
+  "ENABLE_8_3_NAMES=" CTIMEOPT_VAL(SQLITE_ENABLE_8_3_NAMES),
+#endif
+#ifdef SQLITE_ENABLE_API_ARMOR
+  "ENABLE_API_ARMOR",
+#endif
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+  "ENABLE_ATOMIC_WRITE",
+#endif
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+  "ENABLE_BATCH_ATOMIC_WRITE",
+#endif
+#ifdef SQLITE_ENABLE_BYTECODE_VTAB
+  "ENABLE_BYTECODE_VTAB",
+#endif
+#ifdef SQLITE_ENABLE_CEROD
+  "ENABLE_CEROD=" CTIMEOPT_VAL(SQLITE_ENABLE_CEROD),
+#endif
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+  "ENABLE_COLUMN_METADATA",
+#endif
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+  "ENABLE_COLUMN_USED_MASK",
+#endif
+#ifdef SQLITE_ENABLE_COSTMULT
+  "ENABLE_COSTMULT",
+#endif
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+  "ENABLE_CURSOR_HINTS",
+#endif
+#ifdef SQLITE_ENABLE_DBPAGE_VTAB
+  "ENABLE_DBPAGE_VTAB",
+#endif
+#ifdef SQLITE_ENABLE_DBSTAT_VTAB
+  "ENABLE_DBSTAT_VTAB",
+#endif
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+  "ENABLE_EXPENSIVE_ASSERT",
+#endif
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  "ENABLE_EXPLAIN_COMMENTS",
+#endif
+#ifdef SQLITE_ENABLE_FTS3
+  "ENABLE_FTS3",
+#endif
+#ifdef SQLITE_ENABLE_FTS3_PARENTHESIS
+  "ENABLE_FTS3_PARENTHESIS",
+#endif
+#ifdef SQLITE_ENABLE_FTS3_TOKENIZER
+  "ENABLE_FTS3_TOKENIZER",
+#endif
+#ifdef SQLITE_ENABLE_FTS4
+  "ENABLE_FTS4",
+#endif
+#ifdef SQLITE_ENABLE_FTS5
+  "ENABLE_FTS5",
+#endif
+#ifdef SQLITE_ENABLE_GEOPOLY
+  "ENABLE_GEOPOLY",
+#endif
+#ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
+  "ENABLE_HIDDEN_COLUMNS",
+#endif
+#ifdef SQLITE_ENABLE_ICU
+  "ENABLE_ICU",
+#endif
+#ifdef SQLITE_ENABLE_IOTRACE
+  "ENABLE_IOTRACE",
+#endif
+#ifdef SQLITE_ENABLE_LOAD_EXTENSION
+  "ENABLE_LOAD_EXTENSION",
+#endif
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+  "ENABLE_LOCKING_STYLE=" CTIMEOPT_VAL(SQLITE_ENABLE_LOCKING_STYLE),
+#endif
+#ifdef SQLITE_ENABLE_MATH_FUNCTIONS
+  "ENABLE_MATH_FUNCTIONS",
+#endif
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  "ENABLE_MEMORY_MANAGEMENT",
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS3
+  "ENABLE_MEMSYS3",
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS5
+  "ENABLE_MEMSYS5",
+#endif
+#ifdef SQLITE_ENABLE_MULTIPLEX
+  "ENABLE_MULTIPLEX",
+#endif
+#ifdef SQLITE_ENABLE_NORMALIZE
+  "ENABLE_NORMALIZE",
+#endif
+#ifdef SQLITE_ENABLE_NULL_TRIM
+  "ENABLE_NULL_TRIM",
+#endif
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+  "ENABLE_OFFSET_SQL_FUNC",
+#endif
+#ifdef SQLITE_ENABLE_ORDERED_SET_AGGREGATES
+  "ENABLE_ORDERED_SET_AGGREGATES",
+#endif
+#ifdef SQLITE_ENABLE_OVERSIZE_CELL_CHECK
+  "ENABLE_OVERSIZE_CELL_CHECK",
+#endif
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  "ENABLE_PREUPDATE_HOOK",
+#endif
+#ifdef SQLITE_ENABLE_QPSG
+  "ENABLE_QPSG",
+#endif
+#ifdef SQLITE_ENABLE_RBU
+  "ENABLE_RBU",
+#endif
+#ifdef SQLITE_ENABLE_RTREE
+  "ENABLE_RTREE",
+#endif
+#ifdef SQLITE_ENABLE_SESSION
+  "ENABLE_SESSION",
+#endif
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  "ENABLE_SNAPSHOT",
+#endif
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  "ENABLE_SORTER_REFERENCES",
+#endif
+#ifdef SQLITE_ENABLE_SQLLOG
+  "ENABLE_SQLLOG",
+#endif
+#ifdef SQLITE_ENABLE_STAT4
+  "ENABLE_STAT4",
+#endif
+#ifdef SQLITE_ENABLE_STMTVTAB
+  "ENABLE_STMTVTAB",
+#endif
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  "ENABLE_STMT_SCANSTATUS",
+#endif
+#ifdef SQLITE_ENABLE_TREETRACE
+  "ENABLE_TREETRACE",
+#endif
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+  "ENABLE_UNKNOWN_SQL_FUNCTION",
+#endif
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+  "ENABLE_UNLOCK_NOTIFY",
+#endif
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  "ENABLE_UPDATE_DELETE_LIMIT",
+#endif
+#ifdef SQLITE_ENABLE_URI_00_ERROR
+  "ENABLE_URI_00_ERROR",
+#endif
+#ifdef SQLITE_ENABLE_VFSTRACE
+  "ENABLE_VFSTRACE",
+#endif
+#ifdef SQLITE_ENABLE_WHERETRACE
+  "ENABLE_WHERETRACE",
+#endif
+#ifdef SQLITE_ENABLE_ZIPVFS
+  "ENABLE_ZIPVFS",
+#endif
+#ifdef SQLITE_EXPLAIN_ESTIMATED_ROWS
+  "EXPLAIN_ESTIMATED_ROWS",
+#endif
+#ifdef SQLITE_EXTRA_AUTOEXT
+  "EXTRA_AUTOEXT=" CTIMEOPT_VAL(SQLITE_EXTRA_AUTOEXT),
+#endif
+#ifdef SQLITE_EXTRA_IFNULLROW
+  "EXTRA_IFNULLROW",
+#endif
+#ifdef SQLITE_EXTRA_INIT
+  "EXTRA_INIT=" CTIMEOPT_VAL(SQLITE_EXTRA_INIT),
+#endif
+#ifdef SQLITE_EXTRA_SHUTDOWN
+  "EXTRA_SHUTDOWN=" CTIMEOPT_VAL(SQLITE_EXTRA_SHUTDOWN),
+#endif
+#ifdef SQLITE_FTS3_MAX_EXPR_DEPTH
+  "FTS3_MAX_EXPR_DEPTH=" CTIMEOPT_VAL(SQLITE_FTS3_MAX_EXPR_DEPTH),
+#endif
+#ifdef SQLITE_FTS5_ENABLE_TEST_MI
+  "FTS5_ENABLE_TEST_MI",
+#endif
+#ifdef SQLITE_FTS5_NO_WITHOUT_ROWID
+  "FTS5_NO_WITHOUT_ROWID",
+#endif
+#if HAVE_ISNAN || SQLITE_HAVE_ISNAN
+  "HAVE_ISNAN",
+#endif
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+# if SQLITE_HOMEGROWN_RECURSIVE_MUTEX != 1
+  "HOMEGROWN_RECURSIVE_MUTEX=" CTIMEOPT_VAL(SQLITE_HOMEGROWN_RECURSIVE_MUTEX),
+# endif
+#endif
+#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS
+  "IGNORE_AFP_LOCK_ERRORS",
+#endif
+#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
+  "IGNORE_FLOCK_LOCK_ERRORS",
+#endif
+#ifdef SQLITE_INLINE_MEMCPY
+  "INLINE_MEMCPY",
+#endif
+#ifdef SQLITE_INT64_TYPE
+  "INT64_TYPE",
+#endif
+#ifdef SQLITE_INTEGRITY_CHECK_ERROR_MAX
+  "INTEGRITY_CHECK_ERROR_MAX=" CTIMEOPT_VAL(SQLITE_INTEGRITY_CHECK_ERROR_MAX),
+#endif
+#ifdef SQLITE_LEGACY_JSON_VALID
+  "LEGACY_JSON_VALID",
+#endif
+#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+  "LIKE_DOESNT_MATCH_BLOBS",
+#endif
+#ifdef SQLITE_LOCK_TRACE
+  "LOCK_TRACE",
+#endif
+#ifdef SQLITE_LOG_CACHE_SPILL
+  "LOG_CACHE_SPILL",
+#endif
+#ifdef SQLITE_MALLOC_SOFT_LIMIT
+  "MALLOC_SOFT_LIMIT=" CTIMEOPT_VAL(SQLITE_MALLOC_SOFT_LIMIT),
+#endif
+#ifdef SQLITE_MAX_ATTACHED
+  "MAX_ATTACHED=" CTIMEOPT_VAL(SQLITE_MAX_ATTACHED),
+#endif
+#ifdef SQLITE_MAX_COLUMN
+  "MAX_COLUMN=" CTIMEOPT_VAL(SQLITE_MAX_COLUMN),
+#endif
+#ifdef SQLITE_MAX_COMPOUND_SELECT
+  "MAX_COMPOUND_SELECT=" CTIMEOPT_VAL(SQLITE_MAX_COMPOUND_SELECT),
+#endif
+#ifdef SQLITE_MAX_DEFAULT_PAGE_SIZE
+  "MAX_DEFAULT_PAGE_SIZE=" CTIMEOPT_VAL(SQLITE_MAX_DEFAULT_PAGE_SIZE),
+#endif
+#ifdef SQLITE_MAX_EXPR_DEPTH
+  "MAX_EXPR_DEPTH=" CTIMEOPT_VAL(SQLITE_MAX_EXPR_DEPTH),
+#endif
+#ifdef SQLITE_MAX_FUNCTION_ARG
+  "MAX_FUNCTION_ARG=" CTIMEOPT_VAL(SQLITE_MAX_FUNCTION_ARG),
+#endif
+#ifdef SQLITE_MAX_LENGTH
+  "MAX_LENGTH=" CTIMEOPT_VAL(SQLITE_MAX_LENGTH),
+#endif
+#ifdef SQLITE_MAX_LIKE_PATTERN_LENGTH
+  "MAX_LIKE_PATTERN_LENGTH=" CTIMEOPT_VAL(SQLITE_MAX_LIKE_PATTERN_LENGTH),
+#endif
+#ifdef SQLITE_MAX_MEMORY
+  "MAX_MEMORY=" CTIMEOPT_VAL(SQLITE_MAX_MEMORY),
+#endif
+#ifdef SQLITE_MAX_MMAP_SIZE
+  "MAX_MMAP_SIZE=" CTIMEOPT_VAL(SQLITE_MAX_MMAP_SIZE),
+#endif
+#ifdef SQLITE_MAX_MMAP_SIZE_
+  "MAX_MMAP_SIZE_=" CTIMEOPT_VAL(SQLITE_MAX_MMAP_SIZE_),
+#endif
+#ifdef SQLITE_MAX_PAGE_COUNT
+  "MAX_PAGE_COUNT=" CTIMEOPT_VAL(SQLITE_MAX_PAGE_COUNT),
+#endif
+#ifdef SQLITE_MAX_PAGE_SIZE
+  "MAX_PAGE_SIZE=" CTIMEOPT_VAL(SQLITE_MAX_PAGE_SIZE),
+#endif
+#ifdef SQLITE_MAX_SCHEMA_RETRY
+  "MAX_SCHEMA_RETRY=" CTIMEOPT_VAL(SQLITE_MAX_SCHEMA_RETRY),
+#endif
+#ifdef SQLITE_MAX_SQL_LENGTH
+  "MAX_SQL_LENGTH=" CTIMEOPT_VAL(SQLITE_MAX_SQL_LENGTH),
+#endif
+#ifdef SQLITE_MAX_TRIGGER_DEPTH
+  "MAX_TRIGGER_DEPTH=" CTIMEOPT_VAL(SQLITE_MAX_TRIGGER_DEPTH),
+#endif
+#ifdef SQLITE_MAX_VARIABLE_NUMBER
+  "MAX_VARIABLE_NUMBER=" CTIMEOPT_VAL(SQLITE_MAX_VARIABLE_NUMBER),
+#endif
+#ifdef SQLITE_MAX_VDBE_OP
+  "MAX_VDBE_OP=" CTIMEOPT_VAL(SQLITE_MAX_VDBE_OP),
+#endif
+#ifdef SQLITE_MAX_WORKER_THREADS
+  "MAX_WORKER_THREADS=" CTIMEOPT_VAL(SQLITE_MAX_WORKER_THREADS),
+#endif
+#ifdef SQLITE_MEMDEBUG
+  "MEMDEBUG",
+#endif
+#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+  "MIXED_ENDIAN_64BIT_FLOAT",
+#endif
+#ifdef SQLITE_MMAP_READWRITE
+  "MMAP_READWRITE",
+#endif
+#ifdef SQLITE_MUTEX_NOOP
+  "MUTEX_NOOP",
+#endif
+#ifdef SQLITE_MUTEX_OMIT
+  "MUTEX_OMIT",
+#endif
+#ifdef SQLITE_MUTEX_PTHREADS
+  "MUTEX_PTHREADS",
+#endif
+#ifdef SQLITE_MUTEX_W32
+  "MUTEX_W32",
+#endif
+#ifdef SQLITE_NEED_ERR_NAME
+  "NEED_ERR_NAME",
+#endif
+#ifdef SQLITE_NO_SYNC
+  "NO_SYNC",
+#endif
+#ifdef SQLITE_OMIT_ALTERTABLE
+  "OMIT_ALTERTABLE",
+#endif
+#ifdef SQLITE_OMIT_ANALYZE
+  "OMIT_ANALYZE",
+#endif
+#ifdef SQLITE_OMIT_ATTACH
+  "OMIT_ATTACH",
+#endif
+#ifdef SQLITE_OMIT_AUTHORIZATION
+  "OMIT_AUTHORIZATION",
+#endif
+#ifdef SQLITE_OMIT_AUTOINCREMENT
+  "OMIT_AUTOINCREMENT",
+#endif
+#ifdef SQLITE_OMIT_AUTOINIT
+  "OMIT_AUTOINIT",
+#endif
+#ifdef SQLITE_OMIT_AUTOMATIC_INDEX
+  "OMIT_AUTOMATIC_INDEX",
+#endif
+#ifdef SQLITE_OMIT_AUTORESET
+  "OMIT_AUTORESET",
+#endif
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  "OMIT_AUTOVACUUM",
+#endif
+#ifdef SQLITE_OMIT_BETWEEN_OPTIMIZATION
+  "OMIT_BETWEEN_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_BLOB_LITERAL
+  "OMIT_BLOB_LITERAL",
+#endif
+#ifdef SQLITE_OMIT_CAST
+  "OMIT_CAST",
+#endif
+#ifdef SQLITE_OMIT_CHECK
+  "OMIT_CHECK",
+#endif
+#ifdef SQLITE_OMIT_COMPLETE
+  "OMIT_COMPLETE",
+#endif
+#ifdef SQLITE_OMIT_COMPOUND_SELECT
+  "OMIT_COMPOUND_SELECT",
+#endif
+#ifdef SQLITE_OMIT_CONFLICT_CLAUSE
+  "OMIT_CONFLICT_CLAUSE",
+#endif
+#ifdef SQLITE_OMIT_CTE
+  "OMIT_CTE",
+#endif
+#if defined(SQLITE_OMIT_DATETIME_FUNCS) || defined(SQLITE_OMIT_FLOATING_POINT)
+  "OMIT_DATETIME_FUNCS",
+#endif
+#ifdef SQLITE_OMIT_DECLTYPE
+  "OMIT_DECLTYPE",
+#endif
+#ifdef SQLITE_OMIT_DEPRECATED
+  "OMIT_DEPRECATED",
+#endif
+#ifdef SQLITE_OMIT_DESERIALIZE
+  "OMIT_DESERIALIZE",
+#endif
+#ifdef SQLITE_OMIT_DISKIO
+  "OMIT_DISKIO",
+#endif
+#ifdef SQLITE_OMIT_EXPLAIN
+  "OMIT_EXPLAIN",
+#endif
+#ifdef SQLITE_OMIT_FLAG_PRAGMAS
+  "OMIT_FLAG_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_FLOATING_POINT
+  "OMIT_FLOATING_POINT",
+#endif
+#ifdef SQLITE_OMIT_FOREIGN_KEY
+  "OMIT_FOREIGN_KEY",
+#endif
+#ifdef SQLITE_OMIT_GET_TABLE
+  "OMIT_GET_TABLE",
+#endif
+#ifdef SQLITE_OMIT_HEX_INTEGER
+  "OMIT_HEX_INTEGER",
+#endif
+#ifdef SQLITE_OMIT_INCRBLOB
+  "OMIT_INCRBLOB",
+#endif
+#ifdef SQLITE_OMIT_INTEGRITY_CHECK
+  "OMIT_INTEGRITY_CHECK",
+#endif
+#ifdef SQLITE_OMIT_INTROSPECTION_PRAGMAS
+  "OMIT_INTROSPECTION_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_JSON
+  "OMIT_JSON",
+#endif
+#ifdef SQLITE_OMIT_LIKE_OPTIMIZATION
+  "OMIT_LIKE_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_LOAD_EXTENSION
+  "OMIT_LOAD_EXTENSION",
+#endif
+#ifdef SQLITE_OMIT_LOCALTIME
+  "OMIT_LOCALTIME",
+#endif
+#ifdef SQLITE_OMIT_LOOKASIDE
+  "OMIT_LOOKASIDE",
+#endif
+#ifdef SQLITE_OMIT_MEMORYDB
+  "OMIT_MEMORYDB",
+#endif
+#ifdef SQLITE_OMIT_OR_OPTIMIZATION
+  "OMIT_OR_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_PAGER_PRAGMAS
+  "OMIT_PAGER_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_PARSER_TRACE
+  "OMIT_PARSER_TRACE",
+#endif
+#ifdef SQLITE_OMIT_POPEN
+  "OMIT_POPEN",
+#endif
+#ifdef SQLITE_OMIT_PRAGMA
+  "OMIT_PRAGMA",
+#endif
+#ifdef SQLITE_OMIT_PROGRESS_CALLBACK
+  "OMIT_PROGRESS_CALLBACK",
+#endif
+#ifdef SQLITE_OMIT_QUICKBALANCE
+  "OMIT_QUICKBALANCE",
+#endif
+#ifdef SQLITE_OMIT_REINDEX
+  "OMIT_REINDEX",
+#endif
+#ifdef SQLITE_OMIT_SCHEMA_PRAGMAS
+  "OMIT_SCHEMA_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS
+  "OMIT_SCHEMA_VERSION_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_SEH
+  "OMIT_SEH",
+#endif
+#ifdef SQLITE_OMIT_SHARED_CACHE
+  "OMIT_SHARED_CACHE",
+#endif
+#ifdef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
+  "OMIT_SHUTDOWN_DIRECTORIES",
+#endif
+#ifdef SQLITE_OMIT_SUBQUERY
+  "OMIT_SUBQUERY",
+#endif
+#ifdef SQLITE_OMIT_TCL_VARIABLE
+  "OMIT_TCL_VARIABLE",
+#endif
+#ifdef SQLITE_OMIT_TEMPDB
+  "OMIT_TEMPDB",
+#endif
+#ifdef SQLITE_OMIT_TEST_CONTROL
+  "OMIT_TEST_CONTROL",
+#endif
+#ifdef SQLITE_OMIT_TRACE
+# if SQLITE_OMIT_TRACE != 1
+  "OMIT_TRACE=" CTIMEOPT_VAL(SQLITE_OMIT_TRACE),
+# endif
+#endif
+#ifdef SQLITE_OMIT_TRIGGER
+  "OMIT_TRIGGER",
+#endif
+#ifdef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
+  "OMIT_TRUNCATE_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_UTF16
+  "OMIT_UTF16",
+#endif
+#ifdef SQLITE_OMIT_VACUUM
+  "OMIT_VACUUM",
+#endif
+#ifdef SQLITE_OMIT_VIEW
+  "OMIT_VIEW",
+#endif
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+  "OMIT_VIRTUALTABLE",
+#endif
+#ifdef SQLITE_OMIT_WAL
+  "OMIT_WAL",
+#endif
+#ifdef SQLITE_OMIT_WSD
+  "OMIT_WSD",
+#endif
+#ifdef SQLITE_OMIT_XFER_OPT
+  "OMIT_XFER_OPT",
+#endif
+#ifdef SQLITE_PERFORMANCE_TRACE
+  "PERFORMANCE_TRACE",
+#endif
+#ifdef SQLITE_POWERSAFE_OVERWRITE
+# if SQLITE_POWERSAFE_OVERWRITE != 1
+  "POWERSAFE_OVERWRITE=" CTIMEOPT_VAL(SQLITE_POWERSAFE_OVERWRITE),
+# endif
+#endif
+#ifdef SQLITE_PREFER_PROXY_LOCKING
+  "PREFER_PROXY_LOCKING",
+#endif
+#ifdef SQLITE_PROXY_DEBUG
+  "PROXY_DEBUG",
+#endif
+#ifdef SQLITE_REVERSE_UNORDERED_SELECTS
+  "REVERSE_UNORDERED_SELECTS",
+#endif
+#ifdef SQLITE_RTREE_INT_ONLY
+  "RTREE_INT_ONLY",
+#endif
+#ifdef SQLITE_SECURE_DELETE
+  "SECURE_DELETE",
+#endif
+#ifdef SQLITE_SMALL_STACK
+  "SMALL_STACK",
+#endif
+#ifdef SQLITE_SORTER_PMASZ
+  "SORTER_PMASZ=" CTIMEOPT_VAL(SQLITE_SORTER_PMASZ),
+#endif
+#ifdef SQLITE_SOUNDEX
+  "SOUNDEX",
+#endif
+#ifdef SQLITE_STAT4_SAMPLES
+  "STAT4_SAMPLES=" CTIMEOPT_VAL(SQLITE_STAT4_SAMPLES),
+#endif
+#ifdef SQLITE_STMTJRNL_SPILL
+  "STMTJRNL_SPILL=" CTIMEOPT_VAL(SQLITE_STMTJRNL_SPILL),
+#endif
+#ifdef SQLITE_SUBSTR_COMPATIBILITY
+  "SUBSTR_COMPATIBILITY",
+#endif
+#if (!defined(SQLITE_WIN32_MALLOC) \
+     && !defined(SQLITE_ZERO_MALLOC) \
+     && !defined(SQLITE_MEMDEBUG) \
+    ) || defined(SQLITE_SYSTEM_MALLOC)
+  "SYSTEM_MALLOC",
+#endif
+#ifdef SQLITE_TCL
+  "TCL",
+#endif
+#ifdef SQLITE_TEMP_STORE
+  "TEMP_STORE=" CTIMEOPT_VAL(SQLITE_TEMP_STORE),
+#endif
+#ifdef SQLITE_TEST
+  "TEST",
+#endif
+#if defined(SQLITE_THREADSAFE)
+  "THREADSAFE=" CTIMEOPT_VAL(SQLITE_THREADSAFE),
+#elif defined(THREADSAFE)
+  "THREADSAFE=" CTIMEOPT_VAL(THREADSAFE),
+#else
+  "THREADSAFE=1",
+#endif
+#ifdef SQLITE_UNLINK_AFTER_CLOSE
+  "UNLINK_AFTER_CLOSE",
+#endif
+#ifdef SQLITE_UNTESTABLE
+  "UNTESTABLE",
+#endif
+#ifdef SQLITE_USE_ALLOCA
+  "USE_ALLOCA",
+#endif
+#ifdef SQLITE_USE_FCNTL_TRACE
+  "USE_FCNTL_TRACE",
+#endif
+#ifdef SQLITE_USE_URI
+  "USE_URI",
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  "VDBE_COVERAGE",
+#endif
+#ifdef SQLITE_WIN32_MALLOC
+  "WIN32_MALLOC",
+#endif
+#ifdef SQLITE_ZERO_MALLOC
+  "ZERO_MALLOC",
+#endif
+
+} ;
+
+SQLITE_PRIVATE const char **sqlite3CompileOptions(int *pnOpt){
+  *pnOpt = sizeof(sqlite3azCompileOpt) / sizeof(sqlite3azCompileOpt[0]);
+  return (const char**)sqlite3azCompileOpt;
+}
+
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/************** End of ctime.c ***********************************************/
+/************** Begin file global.c ******************************************/
+/*
+** 2008 June 13
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains definitions of global variables and constants.
+*/
+/* #include "sqliteInt.h" */
+
+/* An array to map all upper-case characters into their corresponding
+** lower-case character.
+**
+** SQLite only considers US-ASCII (or EBCDIC) characters.  We do not
+** handle case conversions for the UTF character set since the tables
+** involved are nearly as big or bigger than SQLite itself.
+*/
+SQLITE_PRIVATE const unsigned char sqlite3UpperToLower[] = {
+#ifdef SQLITE_ASCII
+      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17,
+     18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
+     36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
+     54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 97, 98, 99,100,101,102,103,
+    104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,
+    122, 91, 92, 93, 94, 95, 96, 97, 98, 99,100,101,102,103,104,105,106,107,
+    108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,
+    126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
+    144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,
+    162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,
+    180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,
+    198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,
+    216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,
+    234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,
+    252,253,254,255,
+#endif
+#ifdef SQLITE_EBCDIC
+      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, /* 0x */
+     16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, /* 1x */
+     32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, /* 2x */
+     48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, /* 3x */
+     64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, /* 4x */
+     80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, /* 5x */
+     96, 97, 98, 99,100,101,102,103,104,105,106,107,108,109,110,111, /* 6x */
+    112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127, /* 7x */
+    128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143, /* 8x */
+    144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159, /* 9x */
+    160,161,162,163,164,165,166,167,168,169,170,171,140,141,142,175, /* Ax */
+    176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191, /* Bx */
+    192,129,130,131,132,133,134,135,136,137,202,203,204,205,206,207, /* Cx */
+    208,145,146,147,148,149,150,151,152,153,218,219,220,221,222,223, /* Dx */
+    224,225,162,163,164,165,166,167,168,169,234,235,236,237,238,239, /* Ex */
+    240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255, /* Fx */
+#endif
+/* All of the upper-to-lower conversion data is above.  The following
+** 18 integers are completely unrelated.  They are appended to the
+** sqlite3UpperToLower[] array to avoid UBSAN warnings.  Here's what is
+** going on:
+**
+** The SQL comparison operators (<>, =, >, <=, <, and >=) are implemented
+** by invoking sqlite3MemCompare(A,B) which compares values A and B and
+** returns negative, zero, or positive if A is less then, equal to, or
+** greater than B, respectively.  Then the true false results is found by
+** consulting sqlite3aLTb[opcode], sqlite3aEQb[opcode], or
+** sqlite3aGTb[opcode] depending on whether the result of compare(A,B)
+** is negative, zero, or positive, where opcode is the specific opcode.
+** The only works because the comparison opcodes are consecutive and in
+** this order: NE EQ GT LE LT GE.  Various assert()s throughout the code
+** ensure that is the case.
+**
+** These elements must be appended to another array.  Otherwise the
+** index (here shown as [256-OP_Ne]) would be out-of-bounds and thus
+** be undefined behavior.  That's goofy, but the C-standards people thought
+** it was a good idea, so here we are.
+*/
+/* NE  EQ  GT  LE  LT  GE  */
+   1,  0,  0,  1,  1,  0,  /* aLTb[]: Use when compare(A,B) less than zero */
+   0,  1,  0,  1,  0,  1,  /* aEQb[]: Use when compare(A,B) equals zero */
+   1,  0,  1,  0,  0,  1   /* aGTb[]: Use when compare(A,B) greater than zero*/
+};
+SQLITE_PRIVATE const unsigned char *sqlite3aLTb = &sqlite3UpperToLower[256-OP_Ne];
+SQLITE_PRIVATE const unsigned char *sqlite3aEQb = &sqlite3UpperToLower[256+6-OP_Ne];
+SQLITE_PRIVATE const unsigned char *sqlite3aGTb = &sqlite3UpperToLower[256+12-OP_Ne];
+
+/*
+** The following 256 byte lookup table is used to support SQLites built-in
+** equivalents to the following standard library functions:
+**
+**   isspace()                        0x01
+**   isalpha()                        0x02
+**   isdigit()                        0x04
+**   isalnum()                        0x06
+**   isxdigit()                       0x08
+**   toupper()                        0x20
+**   SQLite identifier character      0x40   $, _, or non-ascii
+**   Quote character                  0x80
+**
+** Bit 0x20 is set if the mapped character requires translation to upper
+** case. i.e. if the character is a lower-case ASCII character.
+** If x is a lower-case ASCII character, then its upper-case equivalent
+** is (x - 0x20). Therefore toupper() can be implemented as:
+**
+**   (x & ~(map[x]&0x20))
+**
+** The equivalent of tolower() is implemented using the sqlite3UpperToLower[]
+** array. tolower() is used more often than toupper() by SQLite.
+**
+** Bit 0x40 is set if the character is non-alphanumeric and can be used in an
+** SQLite identifier.  Identifiers are alphanumerics, "_", "$", and any
+** non-ASCII UTF character. Hence the test for whether or not a character is
+** part of an identifier is 0x46.
+*/
+SQLITE_PRIVATE const unsigned char sqlite3CtypeMap[256] = {
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 00..07    ........ */
+  0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00,  /* 08..0f    ........ */
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 10..17    ........ */
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 18..1f    ........ */
+  0x01, 0x00, 0x80, 0x00, 0x40, 0x00, 0x00, 0x80,  /* 20..27     !"#$%&' */
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 28..2f    ()*+,-./ */
+  0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c,  /* 30..37    01234567 */
+  0x0c, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 38..3f    89:;<=>? */
+
+  0x00, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x02,  /* 40..47    @ABCDEFG */
+  0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,  /* 48..4f    HIJKLMNO */
+  0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,  /* 50..57    PQRSTUVW */
+  0x02, 0x02, 0x02, 0x80, 0x00, 0x00, 0x00, 0x40,  /* 58..5f    XYZ[\]^_ */
+  0x80, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x22,  /* 60..67    `abcdefg */
+  0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,  /* 68..6f    hijklmno */
+  0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,  /* 70..77    pqrstuvw */
+  0x22, 0x22, 0x22, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 78..7f    xyz{|}~. */
+
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 80..87    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 88..8f    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 90..97    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 98..9f    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* a0..a7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* a8..af    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* b0..b7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* b8..bf    ........ */
+
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* c0..c7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* c8..cf    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* d0..d7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* d8..df    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e0..e7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e8..ef    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* f0..f7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40   /* f8..ff    ........ */
+};
+
+/* EVIDENCE-OF: R-02982-34736 In order to maintain full backwards
+** compatibility for legacy applications, the URI filename capability is
+** disabled by default.
+**
+** EVIDENCE-OF: R-38799-08373 URI filenames can be enabled or disabled
+** using the SQLITE_USE_URI=1 or SQLITE_USE_URI=0 compile-time options.
+**
+** EVIDENCE-OF: R-43642-56306 By default, URI handling is globally
+** disabled. The default value may be changed by compiling with the
+** SQLITE_USE_URI symbol defined.
+*/
+#ifndef SQLITE_USE_URI
+# define SQLITE_USE_URI 0
+#endif
+
+/* EVIDENCE-OF: R-38720-18127 The default setting is determined by the
+** SQLITE_ALLOW_COVERING_INDEX_SCAN compile-time option, or is "on" if
+** that compile-time option is omitted.
+*/
+#if !defined(SQLITE_ALLOW_COVERING_INDEX_SCAN)
+# define SQLITE_ALLOW_COVERING_INDEX_SCAN 1
+#else
+# if !SQLITE_ALLOW_COVERING_INDEX_SCAN
+#   error "Compile-time disabling of covering index scan using the\
+ -DSQLITE_ALLOW_COVERING_INDEX_SCAN=0 option is deprecated.\
+ Contact SQLite developers if this is a problem for you, and\
+ delete this #error macro to continue with your build."
+# endif
+#endif
+
+/* The minimum PMA size is set to this value multiplied by the database
+** page size in bytes.
+*/
+#ifndef SQLITE_SORTER_PMASZ
+# define SQLITE_SORTER_PMASZ 250
+#endif
+
+/* Statement journals spill to disk when their size exceeds the following
+** threshold (in bytes). 0 means that statement journals are created and
+** written to disk immediately (the default behavior for SQLite versions
+** before 3.12.0).  -1 means always keep the entire statement journal in
+** memory.  (The statement journal is also always held entirely in memory
+** if journal_mode=MEMORY or if temp_store=MEMORY, regardless of this
+** setting.)
+*/
+#ifndef SQLITE_STMTJRNL_SPILL
+# define SQLITE_STMTJRNL_SPILL (64*1024)
+#endif
+
+/*
+** The default lookaside-configuration, the format "SZ,N".  SZ is the
+** number of bytes in each lookaside slot (should be a multiple of 8)
+** and N is the number of slots.  The lookaside-configuration can be
+** changed as start-time using sqlite3_config(SQLITE_CONFIG_LOOKASIDE)
+** or at run-time for an individual database connection using
+** sqlite3_db_config(db, SQLITE_DBCONFIG_LOOKASIDE);
+**
+** With the two-size-lookaside enhancement, less lookaside is required.
+** The default configuration of 1200,40 actually provides 30 1200-byte slots
+** and 93 128-byte slots, which is more lookaside than is available
+** using the older 1200,100 configuration without two-size-lookaside.
+*/
+#ifndef SQLITE_DEFAULT_LOOKASIDE
+# ifdef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+#   define SQLITE_DEFAULT_LOOKASIDE 1200,100  /* 120KB of memory */
+# else
+#   define SQLITE_DEFAULT_LOOKASIDE 1200,40   /* 48KB of memory */
+# endif
+#endif
+
+
+/* The default maximum size of an in-memory database created using
+** sqlite3_deserialize()
+*/
+#ifndef SQLITE_MEMDB_DEFAULT_MAXSIZE
+# define SQLITE_MEMDB_DEFAULT_MAXSIZE 1073741824
+#endif
+
+/*
+** The following singleton contains the global configuration for
+** the SQLite library.
+*/
+SQLITE_PRIVATE SQLITE_WSD struct Sqlite3Config sqlite3Config = {
+   SQLITE_DEFAULT_MEMSTATUS,  /* bMemstat */
+   1,                         /* bCoreMutex */
+   SQLITE_THREADSAFE==1,      /* bFullMutex */
+   SQLITE_USE_URI,            /* bOpenUri */
+   SQLITE_ALLOW_COVERING_INDEX_SCAN,   /* bUseCis */
+   0,                         /* bSmallMalloc */
+   1,                         /* bExtraSchemaChecks */
+#ifdef SQLITE_DEBUG
+   0,                         /* bJsonSelfcheck */
+#endif
+   0x7ffffffe,                /* mxStrlen */
+   0,                         /* neverCorrupt */
+   SQLITE_DEFAULT_LOOKASIDE,  /* szLookaside, nLookaside */
+   SQLITE_STMTJRNL_SPILL,     /* nStmtSpill */
+   {0,0,0,0,0,0,0,0},         /* m */
+   {0,0,0,0,0,0,0,0,0},       /* mutex */
+   {0,0,0,0,0,0,0,0,0,0,0,0,0},/* pcache2 */
+   (void*)0,                  /* pHeap */
+   0,                         /* nHeap */
+   0, 0,                      /* mnHeap, mxHeap */
+   SQLITE_DEFAULT_MMAP_SIZE,  /* szMmap */
+   SQLITE_MAX_MMAP_SIZE,      /* mxMmap */
+   (void*)0,                  /* pPage */
+   0,                         /* szPage */
+   SQLITE_DEFAULT_PCACHE_INITSZ, /* nPage */
+   0,                         /* mxParserStack */
+   0,                         /* sharedCacheEnabled */
+   SQLITE_SORTER_PMASZ,       /* szPma */
+   /* All the rest should always be initialized to zero */
+   0,                         /* isInit */
+   0,                         /* inProgress */
+   0,                         /* isMutexInit */
+   0,                         /* isMallocInit */
+   0,                         /* isPCacheInit */
+   0,                         /* nRefInitMutex */
+   0,                         /* pInitMutex */
+   0,                         /* xLog */
+   0,                         /* pLogArg */
+#ifdef SQLITE_ENABLE_SQLLOG
+   0,                         /* xSqllog */
+   0,                         /* pSqllogArg */
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+   0,                         /* xVdbeBranch */
+   0,                         /* pVbeBranchArg */
+#endif
+#ifndef SQLITE_OMIT_DESERIALIZE
+   SQLITE_MEMDB_DEFAULT_MAXSIZE,   /* mxMemdbSize */
+#endif
+#ifndef SQLITE_UNTESTABLE
+   0,                         /* xTestCallback */
+#endif
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+   0,                         /* mNoVisibleRowid.  0 == allow rowid-in-view */
+#endif
+   0,                         /* bLocaltimeFault */
+   0,                         /* xAltLocaltime */
+   0x7ffffffe,                /* iOnceResetThreshold */
+   SQLITE_DEFAULT_SORTERREF_SIZE,   /* szSorterRef */
+   0,                         /* iPrngSeed */
+#ifdef SQLITE_DEBUG
+   {0,0,0,0,0,0},             /* aTune */
+#endif
+};
+
+/*
+** Hash table for global functions - functions common to all
+** database connections.  After initialization, this table is
+** read-only.
+*/
+SQLITE_PRIVATE FuncDefHash sqlite3BuiltinFunctions;
+
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_DEBUG)
+/*
+** Counter used for coverage testing.  Does not come into play for
+** release builds.
+**
+** Access to this global variable is not mutex protected.  This might
+** result in TSAN warnings.  But as the variable does not exist in
+** release builds, that should not be a concern.
+*/
+SQLITE_PRIVATE unsigned int sqlite3CoverageCounter;
+#endif /* SQLITE_COVERAGE_TEST || SQLITE_DEBUG */
+
+#ifdef VDBE_PROFILE
+/*
+** The following performance counter can be used in place of
+** sqlite3Hwtime() for profiling.  This is a no-op on standard builds.
+*/
+SQLITE_PRIVATE sqlite3_uint64 sqlite3NProfileCnt = 0;
+#endif
+
+/*
+** The value of the "pending" byte must be 0x40000000 (1 byte past the
+** 1-gibabyte boundary) in a compatible database.  SQLite never uses
+** the database page that contains the pending byte.  It never attempts
+** to read or write that page.  The pending byte page is set aside
+** for use by the VFS layers as space for managing file locks.
+**
+** During testing, it is often desirable to move the pending byte to
+** a different position in the file.  This allows code that has to
+** deal with the pending byte to run on files that are much smaller
+** than 1 GiB.  The sqlite3_test_control() interface can be used to
+** move the pending byte.
+**
+** IMPORTANT:  Changing the pending byte to any value other than
+** 0x40000000 results in an incompatible database file format!
+** Changing the pending byte during operation will result in undefined
+** and incorrect behavior.
+*/
+#ifndef SQLITE_OMIT_WSD
+SQLITE_PRIVATE int sqlite3PendingByte = 0x40000000;
+#endif
+
+/*
+** Tracing flags set by SQLITE_TESTCTRL_TRACEFLAGS.
+*/
+SQLITE_PRIVATE u32 sqlite3TreeTrace = 0;
+SQLITE_PRIVATE u32 sqlite3WhereTrace = 0;
+
+/* #include "opcodes.h" */
+/*
+** Properties of opcodes.  The OPFLG_INITIALIZER macro is
+** created by mkopcodeh.awk during compilation.  Data is obtained
+** from the comments following the "case OP_xxxx:" statements in
+** the vdbe.c file.
+*/
+SQLITE_PRIVATE const unsigned char sqlite3OpcodeProperty[] = OPFLG_INITIALIZER;
+
+/*
+** Name of the default collating sequence
+*/
+SQLITE_PRIVATE const char sqlite3StrBINARY[] = "BINARY";
+
+/*
+** Standard typenames.  These names must match the COLTYPE_* definitions.
+** Adjust the SQLITE_N_STDTYPE value if adding or removing entries.
+**
+**    sqlite3StdType[]            The actual names of the datatypes.
+**
+**    sqlite3StdTypeLen[]         The length (in bytes) of each entry
+**                                in sqlite3StdType[].
+**
+**    sqlite3StdTypeAffinity[]    The affinity associated with each entry
+**                                in sqlite3StdType[].
+*/
+SQLITE_PRIVATE const unsigned char sqlite3StdTypeLen[] = { 3, 4, 3, 7, 4, 4 };
+SQLITE_PRIVATE const char sqlite3StdTypeAffinity[] = {
+  SQLITE_AFF_NUMERIC,
+  SQLITE_AFF_BLOB,
+  SQLITE_AFF_INTEGER,
+  SQLITE_AFF_INTEGER,
+  SQLITE_AFF_REAL,
+  SQLITE_AFF_TEXT
+};
+SQLITE_PRIVATE const char *sqlite3StdType[] = {
+  "ANY",
+  "BLOB",
+  "INT",
+  "INTEGER",
+  "REAL",
+  "TEXT"
+};
+
+/************** End of global.c **********************************************/
+/************** Begin file status.c ******************************************/
+/*
+** 2008 June 18
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This module implements the sqlite3_status() interface and related
+** functionality.
+*/
+/* #include "sqliteInt.h" */
+/************** Include vdbeInt.h in the middle of status.c ******************/
+/************** Begin file vdbeInt.h *****************************************/
+/*
+** 2003 September 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for information that is private to the
+** VDBE.  This information used to all be at the top of the single
+** source code file "vdbe.c".  When that file became too big (over
+** 6000 lines long) it was split up into several smaller files and
+** this header information was factored out.
+*/
+#ifndef SQLITE_VDBEINT_H
+#define SQLITE_VDBEINT_H
+
+/*
+** The maximum number of times that a statement will try to reparse
+** itself before giving up and returning SQLITE_SCHEMA.
+*/
+#ifndef SQLITE_MAX_SCHEMA_RETRY
+# define SQLITE_MAX_SCHEMA_RETRY 50
+#endif
+
+/*
+** VDBE_DISPLAY_P4 is true or false depending on whether or not the
+** "explain" P4 display logic is enabled.
+*/
+#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
+     || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG) \
+     || defined(SQLITE_ENABLE_BYTECODE_VTAB)
+# define VDBE_DISPLAY_P4 1
+#else
+# define VDBE_DISPLAY_P4 0
+#endif
+
+/*
+** SQL is translated into a sequence of instructions to be
+** executed by a virtual machine.  Each instruction is an instance
+** of the following structure.
+*/
+typedef struct VdbeOp Op;
+
+/*
+** Boolean values
+*/
+typedef unsigned Bool;
+
+/* Opaque type used by code in vdbesort.c */
+typedef struct VdbeSorter VdbeSorter;
+
+/* Elements of the linked list at Vdbe.pAuxData */
+typedef struct AuxData AuxData;
+
+/* A cache of large TEXT or BLOB values in a VdbeCursor */
+typedef struct VdbeTxtBlbCache VdbeTxtBlbCache;
+
+/* Types of VDBE cursors */
+#define CURTYPE_BTREE       0
+#define CURTYPE_SORTER      1
+#define CURTYPE_VTAB        2
+#define CURTYPE_PSEUDO      3
+
+/*
+** A VdbeCursor is an superclass (a wrapper) for various cursor objects:
+**
+**      * A b-tree cursor
+**          -  In the main database or in an ephemeral database
+**          -  On either an index or a table
+**      * A sorter
+**      * A virtual table
+**      * A one-row "pseudotable" stored in a single register
+*/
+typedef struct VdbeCursor VdbeCursor;
+struct VdbeCursor {
+  u8 eCurType;            /* One of the CURTYPE_* values above */
+  i8 iDb;                 /* Index of cursor database in db->aDb[] */
+  u8 nullRow;             /* True if pointing to a row with no data */
+  u8 deferredMoveto;      /* A call to sqlite3BtreeMoveto() is needed */
+  u8 isTable;             /* True for rowid tables.  False for indexes */
+#ifdef SQLITE_DEBUG
+  u8 seekOp;              /* Most recent seek operation on this cursor */
+  u8 wrFlag;              /* The wrFlag argument to sqlite3BtreeCursor() */
+#endif
+  Bool isEphemeral:1;     /* True for an ephemeral table */
+  Bool useRandomRowid:1;  /* Generate new record numbers semi-randomly */
+  Bool isOrdered:1;       /* True if the table is not BTREE_UNORDERED */
+  Bool noReuse:1;         /* OpenEphemeral may not reuse this cursor */
+  Bool colCache:1;        /* pCache pointer is initialized and non-NULL */
+  u16 seekHit;            /* See the OP_SeekHit and OP_IfNoHope opcodes */
+  union {                 /* pBtx for isEphermeral.  pAltMap otherwise */
+    Btree *pBtx;            /* Separate file holding temporary table */
+    u32 *aAltMap;           /* Mapping from table to index column numbers */
+  } ub;
+  i64 seqCount;           /* Sequence counter */
+
+  /* Cached OP_Column parse information is only valid if cacheStatus matches
+  ** Vdbe.cacheCtr.  Vdbe.cacheCtr will never take on the value of
+  ** CACHE_STALE (0) and so setting cacheStatus=CACHE_STALE guarantees that
+  ** the cache is out of date. */
+  u32 cacheStatus;        /* Cache is valid if this matches Vdbe.cacheCtr */
+  int seekResult;         /* Result of previous sqlite3BtreeMoveto() or 0
+                          ** if there have been no prior seeks on the cursor. */
+  /* seekResult does not distinguish between "no seeks have ever occurred
+  ** on this cursor" and "the most recent seek was an exact match".
+  ** For CURTYPE_PSEUDO, seekResult is the register holding the record */
+
+  /* When a new VdbeCursor is allocated, only the fields above are zeroed.
+  ** The fields that follow are uninitialized, and must be individually
+  ** initialized prior to first use. */
+  VdbeCursor *pAltCursor; /* Associated index cursor from which to read */
+  union {
+    BtCursor *pCursor;          /* CURTYPE_BTREE or _PSEUDO.  Btree cursor */
+    sqlite3_vtab_cursor *pVCur; /* CURTYPE_VTAB.              Vtab cursor */
+    VdbeSorter *pSorter;        /* CURTYPE_SORTER.            Sorter object */
+  } uc;
+  KeyInfo *pKeyInfo;      /* Info about index keys needed by index cursors */
+  u32 iHdrOffset;         /* Offset to next unparsed byte of the header */
+  Pgno pgnoRoot;          /* Root page of the open btree cursor */
+  i16 nField;             /* Number of fields in the header */
+  u16 nHdrParsed;         /* Number of header fields parsed so far */
+  i64 movetoTarget;       /* Argument to the deferred sqlite3BtreeMoveto() */
+  u32 *aOffset;           /* Pointer to aType[nField] */
+  const u8 *aRow;         /* Data for the current row, if all on one page */
+  u32 payloadSize;        /* Total number of bytes in the record */
+  u32 szRow;              /* Byte available in aRow */
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+  u64 maskUsed;           /* Mask of columns used by this cursor */
+#endif
+  VdbeTxtBlbCache *pCache; /* Cache of large TEXT or BLOB values */
+
+  /* 2*nField extra array elements allocated for aType[], beyond the one
+  ** static element declared in the structure.  nField total array slots for
+  ** aType[] and nField+1 array slots for aOffset[] */
+  u32 aType[1];           /* Type values record decode.  MUST BE LAST */
+};
+
+/* Return true if P is a null-only cursor
+*/
+#define IsNullCursor(P) \
+  ((P)->eCurType==CURTYPE_PSEUDO && (P)->nullRow && (P)->seekResult==0)
+
+/*
+** A value for VdbeCursor.cacheStatus that means the cache is always invalid.
+*/
+#define CACHE_STALE 0
+
+/*
+** Large TEXT or BLOB values can be slow to load, so we want to avoid
+** loading them more than once.  For that reason, large TEXT and BLOB values
+** can be stored in a cache defined by this object, and attached to the
+** VdbeCursor using the pCache field.
+*/
+struct VdbeTxtBlbCache {
+  char *pCValue;        /* A RCStr buffer to hold the value */
+  i64 iOffset;          /* File offset of the row being cached */
+  int iCol;             /* Column for which the cache is valid */
+  u32 cacheStatus;      /* Vdbe.cacheCtr value */
+  u32 colCacheCtr;      /* Column cache counter */
+};
+
+/*
+** When a sub-program is executed (OP_Program), a structure of this type
+** is allocated to store the current value of the program counter, as
+** well as the current memory cell array and various other frame specific
+** values stored in the Vdbe struct. When the sub-program is finished,
+** these values are copied back to the Vdbe from the VdbeFrame structure,
+** restoring the state of the VM to as it was before the sub-program
+** began executing.
+**
+** The memory for a VdbeFrame object is allocated and managed by a memory
+** cell in the parent (calling) frame. When the memory cell is deleted or
+** overwritten, the VdbeFrame object is not freed immediately. Instead, it
+** is linked into the Vdbe.pDelFrame list. The contents of the Vdbe.pDelFrame
+** list is deleted when the VM is reset in VdbeHalt(). The reason for doing
+** this instead of deleting the VdbeFrame immediately is to avoid recursive
+** calls to sqlite3VdbeMemRelease() when the memory cells belonging to the
+** child frame are released.
+**
+** The currently executing frame is stored in Vdbe.pFrame. Vdbe.pFrame is
+** set to NULL if the currently executing frame is the main program.
+*/
+typedef struct VdbeFrame VdbeFrame;
+struct VdbeFrame {
+  Vdbe *v;                /* VM this frame belongs to */
+  VdbeFrame *pParent;     /* Parent of this frame, or NULL if parent is main */
+  Op *aOp;                /* Program instructions for parent frame */
+  Mem *aMem;              /* Array of memory cells for parent frame */
+  VdbeCursor **apCsr;     /* Array of Vdbe cursors for parent frame */
+  u8 *aOnce;              /* Bitmask used by OP_Once */
+  void *token;            /* Copy of SubProgram.token */
+  i64 lastRowid;          /* Last insert rowid (sqlite3.lastRowid) */
+  AuxData *pAuxData;      /* Linked list of auxdata allocations */
+#if SQLITE_DEBUG
+  u32 iFrameMagic;        /* magic number for sanity checking */
+#endif
+  int nCursor;            /* Number of entries in apCsr */
+  int pc;                 /* Program Counter in parent (calling) frame */
+  int nOp;                /* Size of aOp array */
+  int nMem;               /* Number of entries in aMem */
+  int nChildMem;          /* Number of memory cells for child frame */
+  int nChildCsr;          /* Number of cursors for child frame */
+  i64 nChange;            /* Statement changes (Vdbe.nChange)     */
+  i64 nDbChange;          /* Value of db->nChange */
+};
+
+/* Magic number for sanity checking on VdbeFrame objects */
+#define SQLITE_FRAME_MAGIC 0x879fb71e
+
+/*
+** Return a pointer to the array of registers allocated for use
+** by a VdbeFrame.
+*/
+#define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))])
+
+/*
+** Internally, the vdbe manipulates nearly all SQL values as Mem
+** structures. Each Mem struct may cache multiple representations (string,
+** integer etc.) of the same value.
+*/
+struct sqlite3_value {
+  union MemValue {
+    double r;           /* Real value used when MEM_Real is set in flags */
+    i64 i;              /* Integer value used when MEM_Int is set in flags */
+    int nZero;          /* Extra zero bytes when MEM_Zero and MEM_Blob set */
+    const char *zPType; /* Pointer type when MEM_Term|MEM_Subtype|MEM_Null */
+    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
+  } u;
+  char *z;            /* String or BLOB value */
+  int n;              /* Number of characters in string value, excluding '\0' */
+  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
+  u8  enc;            /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
+  u8  eSubtype;       /* Subtype for this value */
+  /* ShallowCopy only needs to copy the information above */
+  sqlite3 *db;        /* The associated database connection */
+  int szMalloc;       /* Size of the zMalloc allocation */
+  u32 uTemp;          /* Transient storage for serial_type in OP_MakeRecord */
+  char *zMalloc;      /* Space to hold MEM_Str or MEM_Blob if szMalloc>0 */
+  void (*xDel)(void*);/* Destructor for Mem.z - only valid if MEM_Dyn */
+#ifdef SQLITE_DEBUG
+  Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
+  u16 mScopyFlags;    /* flags value immediately after the shallow copy */
+  u8  bScopy;         /* The pScopyFrom of some other Mem *might* point here */
+#endif
+};
+
+/*
+** Size of struct Mem not including the Mem.zMalloc member or anything that
+** follows.
+*/
+#define MEMCELLSIZE offsetof(Mem,db)
+
+/* One or more of the following flags are set to indicate the
+** representations of the value stored in the Mem struct.
+**
+**  *  MEM_Null                An SQL NULL value
+**
+**  *  MEM_Null|MEM_Zero       An SQL NULL with the virtual table
+**                             UPDATE no-change flag set
+**
+**  *  MEM_Null|MEM_Term|      An SQL NULL, but also contains a
+**        MEM_Subtype          pointer accessible using
+**                             sqlite3_value_pointer().
+**
+**  *  MEM_Null|MEM_Cleared    Special SQL NULL that compares non-equal
+**                             to other NULLs even using the IS operator.
+**
+**  *  MEM_Str                 A string, stored in Mem.z with
+**                             length Mem.n.  Zero-terminated if
+**                             MEM_Term is set.  This flag is
+**                             incompatible with MEM_Blob and
+**                             MEM_Null, but can appear with MEM_Int,
+**                             MEM_Real, and MEM_IntReal.
+**
+**  *  MEM_Blob                A blob, stored in Mem.z length Mem.n.
+**                             Incompatible with MEM_Str, MEM_Null,
+**                             MEM_Int, MEM_Real, and MEM_IntReal.
+**
+**  *  MEM_Blob|MEM_Zero       A blob in Mem.z of length Mem.n plus
+**                             MEM.u.i extra 0x00 bytes at the end.
+**
+**  *  MEM_Int                 Integer stored in Mem.u.i.
+**
+**  *  MEM_Real                Real stored in Mem.u.r.
+**
+**  *  MEM_IntReal             Real stored as an integer in Mem.u.i.
+**
+** If the MEM_Null flag is set, then the value is an SQL NULL value.
+** For a pointer type created using sqlite3_bind_pointer() or
+** sqlite3_result_pointer() the MEM_Term and MEM_Subtype flags are also set.
+**
+** If the MEM_Str flag is set then Mem.z points at a string representation.
+** Usually this is encoded in the same unicode encoding as the main
+** database (see below for exceptions). If the MEM_Term flag is also
+** set, then the string is nul terminated. The MEM_Int and MEM_Real
+** flags may coexist with the MEM_Str flag.
+*/
+#define MEM_Undefined 0x0000   /* Value is undefined */
+#define MEM_Null      0x0001   /* Value is NULL (or a pointer) */
+#define MEM_Str       0x0002   /* Value is a string */
+#define MEM_Int       0x0004   /* Value is an integer */
+#define MEM_Real      0x0008   /* Value is a real number */
+#define MEM_Blob      0x0010   /* Value is a BLOB */
+#define MEM_IntReal   0x0020   /* MEM_Int that stringifies like MEM_Real */
+#define MEM_AffMask   0x003f   /* Mask of affinity bits */
+
+/* Extra bits that modify the meanings of the core datatypes above
+*/
+#define MEM_FromBind  0x0040   /* Value originates from sqlite3_bind() */
+ /*                   0x0080   // Available */
+#define MEM_Cleared   0x0100   /* NULL set by OP_Null, not from data */
+#define MEM_Term      0x0200   /* String in Mem.z is zero terminated */
+#define MEM_Zero      0x0400   /* Mem.i contains count of 0s appended to blob */
+#define MEM_Subtype   0x0800   /* Mem.eSubtype is valid */
+#define MEM_TypeMask  0x0dbf   /* Mask of type bits */
+
+/* Bits that determine the storage for Mem.z for a string or blob or
+** aggregate accumulator.
+*/
+#define MEM_Dyn       0x1000   /* Need to call Mem.xDel() on Mem.z */
+#define MEM_Static    0x2000   /* Mem.z points to a static string */
+#define MEM_Ephem     0x4000   /* Mem.z points to an ephemeral string */
+#define MEM_Agg       0x8000   /* Mem.z points to an agg function context */
+
+/* Return TRUE if Mem X contains dynamically allocated content - anything
+** that needs to be deallocated to avoid a leak.
+*/
+#define VdbeMemDynamic(X)  \
+  (((X)->flags&(MEM_Agg|MEM_Dyn))!=0)
+
+/*
+** Clear any existing type flags from a Mem and replace them with f
+*/
+#define MemSetTypeFlag(p, f) \
+   ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f)
+
+/*
+** True if Mem X is a NULL-nochng type.
+*/
+#define MemNullNochng(X) \
+  (((X)->flags&MEM_TypeMask)==(MEM_Null|MEM_Zero) \
+    && (X)->n==0 && (X)->u.nZero==0)
+
+/*
+** Return true if a memory cell has been initialized and is valid.
+** is for use inside assert() statements only.
+**
+** A Memory cell is initialized if at least one of the
+** MEM_Null, MEM_Str, MEM_Int, MEM_Real, MEM_Blob, or MEM_IntReal bits
+** is set.  It is "undefined" if all those bits are zero.
+*/
+#ifdef SQLITE_DEBUG
+#define memIsValid(M)  ((M)->flags & MEM_AffMask)!=0
+#endif
+
+/*
+** Each auxiliary data pointer stored by a user defined function
+** implementation calling sqlite3_set_auxdata() is stored in an instance
+** of this structure. All such structures associated with a single VM
+** are stored in a linked list headed at Vdbe.pAuxData. All are destroyed
+** when the VM is halted (if not before).
+*/
+struct AuxData {
+  int iAuxOp;                     /* Instruction number of OP_Function opcode */
+  int iAuxArg;                    /* Index of function argument. */
+  void *pAux;                     /* Aux data pointer */
+  void (*xDeleteAux)(void*);      /* Destructor for the aux data */
+  AuxData *pNextAux;              /* Next element in list */
+};
+
+/*
+** The "context" argument for an installable function.  A pointer to an
+** instance of this structure is the first argument to the routines used
+** implement the SQL functions.
+**
+** There is a typedef for this structure in sqlite.h.  So all routines,
+** even the public interface to SQLite, can use a pointer to this structure.
+** But this file is the only place where the internal details of this
+** structure are known.
+**
+** This structure is defined inside of vdbeInt.h because it uses substructures
+** (Mem) which are only defined there.
+*/
+struct sqlite3_context {
+  Mem *pOut;              /* The return value is stored here */
+  FuncDef *pFunc;         /* Pointer to function information */
+  Mem *pMem;              /* Memory cell used to store aggregate context */
+  Vdbe *pVdbe;            /* The VM that owns this context */
+  int iOp;                /* Instruction number of OP_Function */
+  int isError;            /* Error code returned by the function. */
+  u8 enc;                 /* Encoding to use for results */
+  u8 skipFlag;            /* Skip accumulator loading if true */
+  u16 argc;               /* Number of arguments */
+  sqlite3_value *argv[1]; /* Argument set */
+};
+
+/* A bitfield type for use inside of structures.  Always follow with :N where
+** N is the number of bits.
+*/
+typedef unsigned bft;  /* Bit Field Type */
+
+/* The ScanStatus object holds a single value for the
+** sqlite3_stmt_scanstatus() interface.
+**
+** aAddrRange[]:
+**   This array is used by ScanStatus elements associated with EQP
+**   notes that make an SQLITE_SCANSTAT_NCYCLE value available. It is
+**   an array of up to 3 ranges of VM addresses for which the Vdbe.anCycle[]
+**   values should be summed to calculate the NCYCLE value. Each pair of
+**   integer addresses is a start and end address (both inclusive) for a range
+**   instructions. A start value of 0 indicates an empty range.
+*/
+typedef struct ScanStatus ScanStatus;
+struct ScanStatus {
+  int addrExplain;                /* OP_Explain for loop */
+  int aAddrRange[6];
+  int addrLoop;                   /* Address of "loops" counter */
+  int addrVisit;                  /* Address of "rows visited" counter */
+  int iSelectID;                  /* The "Select-ID" for this loop */
+  LogEst nEst;                    /* Estimated output rows per loop */
+  char *zName;                    /* Name of table or index */
+};
+
+/* The DblquoteStr object holds the text of a double-quoted
+** string for a prepared statement.  A linked list of these objects
+** is constructed during statement parsing and is held on Vdbe.pDblStr.
+** When computing a normalized SQL statement for an SQL statement, that
+** list is consulted for each double-quoted identifier to see if the
+** identifier should really be a string literal.
+*/
+typedef struct DblquoteStr DblquoteStr;
+struct DblquoteStr {
+  DblquoteStr *pNextStr;   /* Next string literal in the list */
+  char z[8];               /* Dequoted value for the string */
+};
+
+/*
+** An instance of the virtual machine.  This structure contains the complete
+** state of the virtual machine.
+**
+** The "sqlite3_stmt" structure pointer that is returned by sqlite3_prepare()
+** is really a pointer to an instance of this structure.
+*/
+struct Vdbe {
+  sqlite3 *db;            /* The database connection that owns this statement */
+  Vdbe **ppVPrev,*pVNext; /* Linked list of VDBEs with the same Vdbe.db */
+  Parse *pParse;          /* Parsing context used to create this Vdbe */
+  ynVar nVar;             /* Number of entries in aVar[] */
+  int nMem;               /* Number of memory locations currently allocated */
+  int nCursor;            /* Number of slots in apCsr[] */
+  u32 cacheCtr;           /* VdbeCursor row cache generation counter */
+  int pc;                 /* The program counter */
+  int rc;                 /* Value to return */
+  i64 nChange;            /* Number of db changes made since last reset */
+  int iStatement;         /* Statement number (or 0 if has no opened stmt) */
+  i64 iCurrentTime;       /* Value of julianday('now') for this statement */
+  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
+  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
+  i64 nStmtDefImmCons;    /* Number of def. imm constraints when stmt started */
+  Mem *aMem;              /* The memory locations */
+  Mem **apArg;            /* Arguments to currently executing user function */
+  VdbeCursor **apCsr;     /* One element of this array for each open cursor */
+  Mem *aVar;              /* Values for the OP_Variable opcode. */
+
+  /* When allocating a new Vdbe object, all of the fields below should be
+  ** initialized to zero or NULL */
+
+  Op *aOp;                /* Space to hold the virtual machine's program */
+  int nOp;                /* Number of instructions in the program */
+  int nOpAlloc;           /* Slots allocated for aOp[] */
+  Mem *aColName;          /* Column names to return */
+  Mem *pResultRow;        /* Current output row */
+  char *zErrMsg;          /* Error message written here */
+  VList *pVList;          /* Name of variables */
+#ifndef SQLITE_OMIT_TRACE
+  i64 startTime;          /* Time when query started - used for profiling */
+#endif
+#ifdef SQLITE_DEBUG
+  int rcApp;              /* errcode set by sqlite3_result_error_code() */
+  u32 nWrite;             /* Number of write operations that have occurred */
+#endif
+  u16 nResColumn;         /* Number of columns in one row of the result set */
+  u16 nResAlloc;          /* Column slots allocated to aColName[] */
+  u8 errorAction;         /* Recovery action to do in case of an error */
+  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
+  u8 prepFlags;           /* SQLITE_PREPARE_* flags */
+  u8 eVdbeState;          /* On of the VDBE_*_STATE values */
+  bft expired:2;          /* 1: recompile VM immediately  2: when convenient */
+  bft explain:2;          /* 0: normal, 1: EXPLAIN, 2: EXPLAIN QUERY PLAN */
+  bft changeCntOn:1;      /* True to update the change-counter */
+  bft usesStmtJournal:1;  /* True if uses a statement journal */
+  bft readOnly:1;         /* True for statements that do not write */
+  bft bIsReader:1;        /* True for statements that read */
+  bft haveEqpOps:1;       /* Bytecode supports EXPLAIN QUERY PLAN */
+  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
+  yDbMask lockMask;       /* Subset of btreeMask that requires a lock */
+  u32 aCounter[9];        /* Counters used by sqlite3_stmt_status() */
+  char *zSql;             /* Text of the SQL statement that generated this */
+#ifdef SQLITE_ENABLE_NORMALIZE
+  char *zNormSql;         /* Normalization of the associated SQL statement */
+  DblquoteStr *pDblStr;   /* List of double-quoted string literals */
+#endif
+  void *pFree;            /* Free this when deleting the vdbe */
+  VdbeFrame *pFrame;      /* Parent frame */
+  VdbeFrame *pDelFrame;   /* List of frame objects to free on VM reset */
+  int nFrame;             /* Number of frames in pFrame list */
+  u32 expmask;            /* Binding to these vars invalidates VM */
+  SubProgram *pProgram;   /* Linked list of all sub-programs used by VM */
+  AuxData *pAuxData;      /* Linked list of auxdata allocations */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int nScan;              /* Entries in aScan[] */
+  ScanStatus *aScan;      /* Scan definitions for sqlite3_stmt_scanstatus() */
+#endif
+};
+
+/*
+** The following are allowed values for Vdbe.eVdbeState
+*/
+#define VDBE_INIT_STATE     0   /* Prepared statement under construction */
+#define VDBE_READY_STATE    1   /* Ready to run but not yet started */
+#define VDBE_RUN_STATE      2   /* Run in progress */
+#define VDBE_HALT_STATE     3   /* Finished.  Need reset() or finalize() */
+
+/*
+** Structure used to store the context required by the
+** sqlite3_preupdate_*() API functions.
+*/
+struct PreUpdate {
+  Vdbe *v;
+  VdbeCursor *pCsr;               /* Cursor to read old values from */
+  int op;                         /* One of SQLITE_INSERT, UPDATE, DELETE */
+  u8 *aRecord;                    /* old.* database record */
+  KeyInfo keyinfo;
+  UnpackedRecord *pUnpacked;      /* Unpacked version of aRecord[] */
+  UnpackedRecord *pNewUnpacked;   /* Unpacked version of new.* record */
+  int iNewReg;                    /* Register for new.* values */
+  int iBlobWrite;                 /* Value returned by preupdate_blobwrite() */
+  i64 iKey1;                      /* First key value passed to hook */
+  i64 iKey2;                      /* Second key value passed to hook */
+  Mem oldipk;                     /* Memory cell holding "old" IPK value */
+  Mem *aNew;                      /* Array of new.* values */
+  Table *pTab;                    /* Schema object being updated */
+  Index *pPk;                     /* PK index if pTab is WITHOUT ROWID */
+  sqlite3_value **apDflt;         /* Array of default values, if required */
+};
+
+/*
+** An instance of this object is used to pass an vector of values into
+** OP_VFilter, the xFilter method of a virtual table.  The vector is the
+** set of values on the right-hand side of an IN constraint.
+**
+** The value as passed into xFilter is an sqlite3_value with a "pointer"
+** type, such as is generated by sqlite3_result_pointer() and read by
+** sqlite3_value_pointer.  Such values have MEM_Term|MEM_Subtype|MEM_Null
+** and a subtype of 'p'.  The sqlite3_vtab_in_first() and _next() interfaces
+** know how to use this object to step through all the values in the
+** right operand of the IN constraint.
+*/
+typedef struct ValueList ValueList;
+struct ValueList {
+  BtCursor *pCsr;          /* An ephemeral table holding all values */
+  sqlite3_value *pOut;     /* Register to hold each decoded output value */
+};
+
+/* Size of content associated with serial types that fit into a
+** single-byte varint.
+*/
+#ifndef SQLITE_AMALGAMATION
+SQLITE_PRIVATE const u8 sqlite3SmallTypeSizes[];
+#endif
+
+/*
+** Function prototypes
+*/
+SQLITE_PRIVATE void sqlite3VdbeError(Vdbe*, const char *, ...);
+SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*);
+SQLITE_PRIVATE void sqlite3VdbeFreeCursorNN(Vdbe*,VdbeCursor*);
+void sqliteVdbePopStack(Vdbe*,int);
+SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeHandleMovedCursor(VdbeCursor *p);
+SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeFinishMoveto(VdbeCursor*);
+SQLITE_PRIVATE int sqlite3VdbeCursorRestore(VdbeCursor*);
+SQLITE_PRIVATE u32 sqlite3VdbeSerialTypeLen(u32);
+SQLITE_PRIVATE u8 sqlite3VdbeOneByteSerialTypeLen(u8);
+#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+SQLITE_PRIVATE   u64 sqlite3FloatSwap(u64 in);
+# define swapMixedEndianFloat(X)  X = sqlite3FloatSwap(X)
+#else
+# define swapMixedEndianFloat(X)
+#endif
+SQLITE_PRIVATE void sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
+SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(sqlite3*, AuxData**, int, int);
+
+int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
+SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(sqlite3*,VdbeCursor*,UnpackedRecord*,int*);
+SQLITE_PRIVATE int sqlite3VdbeIdxRowid(sqlite3*, BtCursor*, i64*);
+SQLITE_PRIVATE int sqlite3VdbeExec(Vdbe*);
+#if !defined(SQLITE_OMIT_EXPLAIN) || defined(SQLITE_ENABLE_BYTECODE_VTAB)
+SQLITE_PRIVATE int sqlite3VdbeNextOpcode(Vdbe*,Mem*,int,int*,int*,Op**);
+SQLITE_PRIVATE char *sqlite3VdbeDisplayP4(sqlite3*,Op*);
+#endif
+#if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS)
+SQLITE_PRIVATE char *sqlite3VdbeDisplayComment(sqlite3*,const Op*,const char*);
+#endif
+#if !defined(SQLITE_OMIT_EXPLAIN)
+SQLITE_PRIVATE int sqlite3VdbeList(Vdbe*);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeChangeEncoding(Mem *, int);
+SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem*, const Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
+SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem*, Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemSetStr(Mem*, const char*, i64, u8, void(*)(void*));
+SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem*, i64);
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define sqlite3VdbeMemSetDouble sqlite3VdbeMemSetInt64
+#else
+SQLITE_PRIVATE   void sqlite3VdbeMemSetDouble(Mem*, double);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeMemSetPointer(Mem*, void*, const char*, void(*)(void*));
+SQLITE_PRIVATE void sqlite3VdbeMemInit(Mem*,sqlite3*,u16);
+SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem*);
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem*,int);
+#else
+SQLITE_PRIVATE int sqlite3VdbeMemSetZeroBlob(Mem*,int);
+#endif
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3VdbeMemIsRowSet(const Mem*);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeMemSetRowSet(Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemZeroTerminateIfAble(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem*, u8, u8);
+SQLITE_PRIVATE int sqlite3IntFloatCompare(i64,double);
+SQLITE_PRIVATE i64 sqlite3VdbeIntValue(const Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem*);
+SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeBooleanValue(Mem*, int ifNull);
+SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemCast(Mem*,u8,u8);
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(BtCursor*,u32,u32,Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtreeZeroOffset(BtCursor*,u32,Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p);
+SQLITE_PRIVATE void sqlite3VdbeMemReleaseMalloc(Mem*p);
+SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE int sqlite3VdbeMemAggValue(Mem*, Mem*, FuncDef*);
+#endif
+#if !defined(SQLITE_OMIT_EXPLAIN) || defined(SQLITE_ENABLE_BYTECODE_VTAB)
+SQLITE_PRIVATE const char *sqlite3OpcodeName(int);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
+SQLITE_PRIVATE int sqlite3VdbeMemClearAndResize(Mem *pMem, int n);
+SQLITE_PRIVATE int sqlite3VdbeCloseStatement(Vdbe *, int);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3VdbeFrameIsValid(VdbeFrame*);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeFrameMemDel(void*);      /* Destructor on Mem */
+SQLITE_PRIVATE void sqlite3VdbeFrameDelete(VdbeFrame*); /* Actually deletes the Frame */
+SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *);
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+SQLITE_PRIVATE void sqlite3VdbePreUpdateHook(
+    Vdbe*,VdbeCursor*,int,const char*,Table*,i64,int,int);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeTransferError(Vdbe *p);
+
+SQLITE_PRIVATE int sqlite3VdbeSorterInit(sqlite3 *, int, VdbeCursor *);
+SQLITE_PRIVATE void sqlite3VdbeSorterReset(sqlite3 *, VdbeSorter *);
+SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *, VdbeCursor *);
+SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(const VdbeCursor *, Mem *);
+SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *, const VdbeCursor *);
+SQLITE_PRIVATE int sqlite3VdbeSorterRewind(const VdbeCursor *, int *);
+SQLITE_PRIVATE int sqlite3VdbeSorterWrite(const VdbeCursor *, Mem *);
+SQLITE_PRIVATE int sqlite3VdbeSorterCompare(const VdbeCursor *, Mem *, int, int *);
+
+SQLITE_PRIVATE void sqlite3VdbeValueListFree(void*);
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3VdbeIncrWriteCounter(Vdbe*, VdbeCursor*);
+SQLITE_PRIVATE   void sqlite3VdbeAssertAbortable(Vdbe*);
+#else
+# define sqlite3VdbeIncrWriteCounter(V,C)
+# define sqlite3VdbeAssertAbortable(V)
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE)
+SQLITE_PRIVATE   void sqlite3VdbeEnter(Vdbe*);
+#else
+# define sqlite3VdbeEnter(X)
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0
+SQLITE_PRIVATE   void sqlite3VdbeLeave(Vdbe*);
+#else
+# define sqlite3VdbeLeave(X)
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE void sqlite3VdbeMemAboutToChange(Vdbe*,Mem*);
+SQLITE_PRIVATE int sqlite3VdbeCheckMemInvariants(Mem*);
+#endif
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+SQLITE_PRIVATE int sqlite3VdbeCheckFk(Vdbe *, int);
+#else
+# define sqlite3VdbeCheckFk(p,i) 0
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3VdbePrintSql(Vdbe*);
+SQLITE_PRIVATE   void sqlite3VdbeMemPrettyPrint(Mem *pMem, StrAccum *pStr);
+#endif
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_PRIVATE   int sqlite3VdbeMemTranslate(Mem*, u8);
+SQLITE_PRIVATE   int sqlite3VdbeMemHandleBom(Mem *pMem);
+#endif
+
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE   int sqlite3VdbeMemExpandBlob(Mem *);
+  #define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
+#else
+  #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
+  #define ExpandBlob(P) SQLITE_OK
+#endif
+
+#endif /* !defined(SQLITE_VDBEINT_H) */
+
+/************** End of vdbeInt.h *********************************************/
+/************** Continuing where we left off in status.c *********************/
+
+/*
+** Variables in which to record status information.
+*/
+#if SQLITE_PTRSIZE>4
+typedef sqlite3_int64 sqlite3StatValueType;
+#else
+typedef u32 sqlite3StatValueType;
+#endif
+typedef struct sqlite3StatType sqlite3StatType;
+static SQLITE_WSD struct sqlite3StatType {
+  sqlite3StatValueType nowValue[10];  /* Current value */
+  sqlite3StatValueType mxValue[10];   /* Maximum value */
+} sqlite3Stat = { {0,}, {0,} };
+
+/*
+** Elements of sqlite3Stat[] are protected by either the memory allocator
+** mutex, or by the pcache1 mutex.  The following array determines which.
+*/
+static const char statMutex[] = {
+  0,  /* SQLITE_STATUS_MEMORY_USED */
+  1,  /* SQLITE_STATUS_PAGECACHE_USED */
+  1,  /* SQLITE_STATUS_PAGECACHE_OVERFLOW */
+  0,  /* SQLITE_STATUS_SCRATCH_USED */
+  0,  /* SQLITE_STATUS_SCRATCH_OVERFLOW */
+  0,  /* SQLITE_STATUS_MALLOC_SIZE */
+  0,  /* SQLITE_STATUS_PARSER_STACK */
+  1,  /* SQLITE_STATUS_PAGECACHE_SIZE */
+  0,  /* SQLITE_STATUS_SCRATCH_SIZE */
+  0,  /* SQLITE_STATUS_MALLOC_COUNT */
+};
+
+
+/* The "wsdStat" macro will resolve to the status information
+** state vector.  If writable static data is unsupported on the target,
+** we have to locate the state vector at run-time.  In the more common
+** case where writable static data is supported, wsdStat can refer directly
+** to the "sqlite3Stat" state vector declared above.
+*/
+#ifdef SQLITE_OMIT_WSD
+# define wsdStatInit  sqlite3StatType *x = &GLOBAL(sqlite3StatType,sqlite3Stat)
+# define wsdStat x[0]
+#else
+# define wsdStatInit
+# define wsdStat sqlite3Stat
+#endif
+
+/*
+** Return the current value of a status parameter.  The caller must
+** be holding the appropriate mutex.
+*/
+SQLITE_PRIVATE sqlite3_int64 sqlite3StatusValue(int op){
+  wsdStatInit;
+  assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
+  assert( op>=0 && op<ArraySize(statMutex) );
+  assert( sqlite3_mutex_held(statMutex[op] ? sqlite3Pcache1Mutex()
+                                           : sqlite3MallocMutex()) );
+  return wsdStat.nowValue[op];
+}
+
+/*
+** Add N to the value of a status record.  The caller must hold the
+** appropriate mutex.  (Locking is checked by assert()).
+**
+** The StatusUp() routine can accept positive or negative values for N.
+** The value of N is added to the current status value and the high-water
+** mark is adjusted if necessary.
+**
+** The StatusDown() routine lowers the current value by N.  The highwater
+** mark is unchanged.  N must be non-negative for StatusDown().
+*/
+SQLITE_PRIVATE void sqlite3StatusUp(int op, int N){
+  wsdStatInit;
+  assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
+  assert( op>=0 && op<ArraySize(statMutex) );
+  assert( sqlite3_mutex_held(statMutex[op] ? sqlite3Pcache1Mutex()
+                                           : sqlite3MallocMutex()) );
+  wsdStat.nowValue[op] += N;
+  if( wsdStat.nowValue[op]>wsdStat.mxValue[op] ){
+    wsdStat.mxValue[op] = wsdStat.nowValue[op];
+  }
+}
+SQLITE_PRIVATE void sqlite3StatusDown(int op, int N){
+  wsdStatInit;
+  assert( N>=0 );
+  assert( op>=0 && op<ArraySize(statMutex) );
+  assert( sqlite3_mutex_held(statMutex[op] ? sqlite3Pcache1Mutex()
+                                           : sqlite3MallocMutex()) );
+  assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
+  wsdStat.nowValue[op] -= N;
+}
+
+/*
+** Adjust the highwater mark if necessary.
+** The caller must hold the appropriate mutex.
+*/
+SQLITE_PRIVATE void sqlite3StatusHighwater(int op, int X){
+  sqlite3StatValueType newValue;
+  wsdStatInit;
+  assert( X>=0 );
+  newValue = (sqlite3StatValueType)X;
+  assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
+  assert( op>=0 && op<ArraySize(statMutex) );
+  assert( sqlite3_mutex_held(statMutex[op] ? sqlite3Pcache1Mutex()
+                                           : sqlite3MallocMutex()) );
+  assert( op==SQLITE_STATUS_MALLOC_SIZE
+          || op==SQLITE_STATUS_PAGECACHE_SIZE
+          || op==SQLITE_STATUS_PARSER_STACK );
+  if( newValue>wsdStat.mxValue[op] ){
+    wsdStat.mxValue[op] = newValue;
+  }
+}
+
+/*
+** Query status information.
+*/
+SQLITE_API int sqlite3_status64(
+  int op,
+  sqlite3_int64 *pCurrent,
+  sqlite3_int64 *pHighwater,
+  int resetFlag
+){
+  sqlite3_mutex *pMutex;
+  wsdStatInit;
+  if( op<0 || op>=ArraySize(wsdStat.nowValue) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCurrent==0 || pHighwater==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  pMutex = statMutex[op] ? sqlite3Pcache1Mutex() : sqlite3MallocMutex();
+  sqlite3_mutex_enter(pMutex);
+  *pCurrent = wsdStat.nowValue[op];
+  *pHighwater = wsdStat.mxValue[op];
+  if( resetFlag ){
+    wsdStat.mxValue[op] = wsdStat.nowValue[op];
+  }
+  sqlite3_mutex_leave(pMutex);
+  (void)pMutex;  /* Prevent warning when SQLITE_THREADSAFE=0 */
+  return SQLITE_OK;
+}
+SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag){
+  sqlite3_int64 iCur = 0, iHwtr = 0;
+  int rc;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCurrent==0 || pHighwater==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  rc = sqlite3_status64(op, &iCur, &iHwtr, resetFlag);
+  if( rc==0 ){
+    *pCurrent = (int)iCur;
+    *pHighwater = (int)iHwtr;
+  }
+  return rc;
+}
+
+/*
+** Return the number of LookasideSlot elements on the linked list
+*/
+static u32 countLookasideSlots(LookasideSlot *p){
+  u32 cnt = 0;
+  while( p ){
+    p = p->pNext;
+    cnt++;
+  }
+  return cnt;
+}
+
+/*
+** Count the number of slots of lookaside memory that are outstanding
+*/
+SQLITE_PRIVATE int sqlite3LookasideUsed(sqlite3 *db, int *pHighwater){
+  u32 nInit = countLookasideSlots(db->lookaside.pInit);
+  u32 nFree = countLookasideSlots(db->lookaside.pFree);
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  nInit += countLookasideSlots(db->lookaside.pSmallInit);
+  nFree += countLookasideSlots(db->lookaside.pSmallFree);
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+  if( pHighwater ) *pHighwater = db->lookaside.nSlot - nInit;
+  return db->lookaside.nSlot - (nInit+nFree);
+}
+
+/*
+** Query status information for a single database connection
+*/
+SQLITE_API int sqlite3_db_status(
+  sqlite3 *db,          /* The database connection whose status is desired */
+  int op,               /* Status verb */
+  int *pCurrent,        /* Write current value here */
+  int *pHighwater,      /* Write high-water mark here */
+  int resetFlag         /* Reset high-water mark if true */
+){
+  int rc = SQLITE_OK;   /* Return code */
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || pCurrent==0|| pHighwater==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  switch( op ){
+    case SQLITE_DBSTATUS_LOOKASIDE_USED: {
+      *pCurrent = sqlite3LookasideUsed(db, pHighwater);
+      if( resetFlag ){
+        LookasideSlot *p = db->lookaside.pFree;
+        if( p ){
+          while( p->pNext ) p = p->pNext;
+          p->pNext = db->lookaside.pInit;
+          db->lookaside.pInit = db->lookaside.pFree;
+          db->lookaside.pFree = 0;
+        }
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+        p = db->lookaside.pSmallFree;
+        if( p ){
+          while( p->pNext ) p = p->pNext;
+          p->pNext = db->lookaside.pSmallInit;
+          db->lookaside.pSmallInit = db->lookaside.pSmallFree;
+          db->lookaside.pSmallFree = 0;
+        }
+#endif
+      }
+      break;
+    }
+
+    case SQLITE_DBSTATUS_LOOKASIDE_HIT:
+    case SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE:
+    case SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL: {
+      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_HIT );
+      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE );
+      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL );
+      assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)>=0 );
+      assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)<3 );
+      *pCurrent = 0;
+      *pHighwater = db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT];
+      if( resetFlag ){
+        db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT] = 0;
+      }
+      break;
+    }
+
+    /*
+    ** Return an approximation for the amount of memory currently used
+    ** by all pagers associated with the given database connection.  The
+    ** highwater mark is meaningless and is returned as zero.
+    */
+    case SQLITE_DBSTATUS_CACHE_USED_SHARED:
+    case SQLITE_DBSTATUS_CACHE_USED: {
+      int totalUsed = 0;
+      int i;
+      sqlite3BtreeEnterAll(db);
+      for(i=0; i<db->nDb; i++){
+        Btree *pBt = db->aDb[i].pBt;
+        if( pBt ){
+          Pager *pPager = sqlite3BtreePager(pBt);
+          int nByte = sqlite3PagerMemUsed(pPager);
+          if( op==SQLITE_DBSTATUS_CACHE_USED_SHARED ){
+            nByte = nByte / sqlite3BtreeConnectionCount(pBt);
+          }
+          totalUsed += nByte;
+        }
+      }
+      sqlite3BtreeLeaveAll(db);
+      *pCurrent = totalUsed;
+      *pHighwater = 0;
+      break;
+    }
+
+    /*
+    ** *pCurrent gets an accurate estimate of the amount of memory used
+    ** to store the schema for all databases (main, temp, and any ATTACHed
+    ** databases.  *pHighwater is set to zero.
+    */
+    case SQLITE_DBSTATUS_SCHEMA_USED: {
+      int i;                      /* Used to iterate through schemas */
+      int nByte = 0;              /* Used to accumulate return value */
+
+      sqlite3BtreeEnterAll(db);
+      db->pnBytesFreed = &nByte;
+      assert( db->lookaside.pEnd==db->lookaside.pTrueEnd );
+      db->lookaside.pEnd = db->lookaside.pStart;
+      for(i=0; i<db->nDb; i++){
+        Schema *pSchema = db->aDb[i].pSchema;
+        if( ALWAYS(pSchema!=0) ){
+          HashElem *p;
+
+          nByte += sqlite3GlobalConfig.m.xRoundup(sizeof(HashElem)) * (
+              pSchema->tblHash.count
+            + pSchema->trigHash.count
+            + pSchema->idxHash.count
+            + pSchema->fkeyHash.count
+          );
+          nByte += sqlite3_msize(pSchema->tblHash.ht);
+          nByte += sqlite3_msize(pSchema->trigHash.ht);
+          nByte += sqlite3_msize(pSchema->idxHash.ht);
+          nByte += sqlite3_msize(pSchema->fkeyHash.ht);
+
+          for(p=sqliteHashFirst(&pSchema->trigHash); p; p=sqliteHashNext(p)){
+            sqlite3DeleteTrigger(db, (Trigger*)sqliteHashData(p));
+          }
+          for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
+            sqlite3DeleteTable(db, (Table *)sqliteHashData(p));
+          }
+        }
+      }
+      db->pnBytesFreed = 0;
+      db->lookaside.pEnd = db->lookaside.pTrueEnd;
+      sqlite3BtreeLeaveAll(db);
+
+      *pHighwater = 0;
+      *pCurrent = nByte;
+      break;
+    }
+
+    /*
+    ** *pCurrent gets an accurate estimate of the amount of memory used
+    ** to store all prepared statements.
+    ** *pHighwater is set to zero.
+    */
+    case SQLITE_DBSTATUS_STMT_USED: {
+      struct Vdbe *pVdbe;         /* Used to iterate through VMs */
+      int nByte = 0;              /* Used to accumulate return value */
+
+      db->pnBytesFreed = &nByte;
+      assert( db->lookaside.pEnd==db->lookaside.pTrueEnd );
+      db->lookaside.pEnd = db->lookaside.pStart;
+      for(pVdbe=db->pVdbe; pVdbe; pVdbe=pVdbe->pVNext){
+        sqlite3VdbeDelete(pVdbe);
+      }
+      db->lookaside.pEnd = db->lookaside.pTrueEnd;
+      db->pnBytesFreed = 0;
+
+      *pHighwater = 0;  /* IMP: R-64479-57858 */
+      *pCurrent = nByte;
+
+      break;
+    }
+
+    /*
+    ** Set *pCurrent to the total cache hits or misses encountered by all
+    ** pagers the database handle is connected to. *pHighwater is always set
+    ** to zero.
+    */
+    case SQLITE_DBSTATUS_CACHE_SPILL:
+      op = SQLITE_DBSTATUS_CACHE_WRITE+1;
+      /* no break */ deliberate_fall_through
+    case SQLITE_DBSTATUS_CACHE_HIT:
+    case SQLITE_DBSTATUS_CACHE_MISS:
+    case SQLITE_DBSTATUS_CACHE_WRITE:{
+      int i;
+      u64 nRet = 0;
+      assert( SQLITE_DBSTATUS_CACHE_MISS==SQLITE_DBSTATUS_CACHE_HIT+1 );
+      assert( SQLITE_DBSTATUS_CACHE_WRITE==SQLITE_DBSTATUS_CACHE_HIT+2 );
+
+      for(i=0; i<db->nDb; i++){
+        if( db->aDb[i].pBt ){
+          Pager *pPager = sqlite3BtreePager(db->aDb[i].pBt);
+          sqlite3PagerCacheStat(pPager, op, resetFlag, &nRet);
+        }
+      }
+      *pHighwater = 0; /* IMP: R-42420-56072 */
+                       /* IMP: R-54100-20147 */
+                       /* IMP: R-29431-39229 */
+      *pCurrent = (int)nRet & 0x7fffffff;
+      break;
+    }
+
+    /* Set *pCurrent to non-zero if there are unresolved deferred foreign
+    ** key constraints.  Set *pCurrent to zero if all foreign key constraints
+    ** have been satisfied.  The *pHighwater is always set to zero.
+    */
+    case SQLITE_DBSTATUS_DEFERRED_FKS: {
+      *pHighwater = 0;  /* IMP: R-11967-56545 */
+      *pCurrent = db->nDeferredImmCons>0 || db->nDeferredCons>0;
+      break;
+    }
+
+    default: {
+      rc = SQLITE_ERROR;
+    }
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/************** End of status.c **********************************************/
+/************** Begin file date.c ********************************************/
+/*
+** 2003 October 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement date and time
+** functions for SQLite.
+**
+** There is only one exported symbol in this file - the function
+** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
+** All other code has file scope.
+**
+** SQLite processes all times and dates as julian day numbers.  The
+** dates and times are stored as the number of days since noon
+** in Greenwich on November 24, 4714 B.C. according to the Gregorian
+** calendar system.
+**
+** 1970-01-01 00:00:00 is JD 2440587.5
+** 2000-01-01 00:00:00 is JD 2451544.5
+**
+** This implementation requires years to be expressed as a 4-digit number
+** which means that only dates between 0000-01-01 and 9999-12-31 can
+** be represented, even though julian day numbers allow a much wider
+** range of dates.
+**
+** The Gregorian calendar system is used for all dates and times,
+** even those that predate the Gregorian calendar.  Historians usually
+** use the julian calendar for dates prior to 1582-10-15 and for some
+** dates afterwards, depending on locale.  Beware of this difference.
+**
+** The conversion algorithms are implemented based on descriptions
+** in the following text:
+**
+**      Jean Meeus
+**      Astronomical Algorithms, 2nd Edition, 1998
+**      ISBN 0-943396-61-1
+**      Willmann-Bell, Inc
+**      Richmond, Virginia (USA)
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdlib.h> */
+/* #include <assert.h> */
+#include <time.h>
+
+#ifndef SQLITE_OMIT_DATETIME_FUNCS
+
+/*
+** The MSVC CRT on Windows CE may not have a localtime() function.
+** So declare a substitute.  The substitute function itself is
+** defined in "os_win.c".
+*/
+#if !defined(SQLITE_OMIT_LOCALTIME) && defined(_WIN32_WCE) && \
+    (!defined(SQLITE_MSVC_LOCALTIME_API) || !SQLITE_MSVC_LOCALTIME_API)
+struct tm *__cdecl localtime(const time_t *);
+#endif
+
+/*
+** A structure for holding a single date and time.
+*/
+typedef struct DateTime DateTime;
+struct DateTime {
+  sqlite3_int64 iJD;  /* The julian day number times 86400000 */
+  int Y, M, D;        /* Year, month, and day */
+  int h, m;           /* Hour and minutes */
+  int tz;             /* Timezone offset in minutes */
+  double s;           /* Seconds */
+  char validJD;       /* True (1) if iJD is valid */
+  char validYMD;      /* True (1) if Y,M,D are valid */
+  char validHMS;      /* True (1) if h,m,s are valid */
+  char nFloor;            /* Days to implement "floor" */
+  unsigned rawS      : 1; /* Raw numeric value stored in s */
+  unsigned isError   : 1; /* An overflow has occurred */
+  unsigned useSubsec : 1; /* Display subsecond precision */
+  unsigned isUtc     : 1; /* Time is known to be UTC */
+  unsigned isLocal   : 1; /* Time is known to be localtime */
+};
+
+
+/*
+** Convert zDate into one or more integers according to the conversion
+** specifier zFormat.
+**
+** zFormat[] contains 4 characters for each integer converted, except for
+** the last integer which is specified by three characters.  The meaning
+** of a four-character format specifiers ABCD is:
+**
+**    A:   number of digits to convert.  Always "2" or "4".
+**    B:   minimum value.  Always "0" or "1".
+**    C:   maximum value, decoded as:
+**           a:  12
+**           b:  14
+**           c:  24
+**           d:  31
+**           e:  59
+**           f:  9999
+**    D:   the separator character, or \000 to indicate this is the
+**         last number to convert.
+**
+** Example:  To translate an ISO-8601 date YYYY-MM-DD, the format would
+** be "40f-21a-20c".  The "40f-" indicates the 4-digit year followed by "-".
+** The "21a-" indicates the 2-digit month followed by "-".  The "20c" indicates
+** the 2-digit day which is the last integer in the set.
+**
+** The function returns the number of successful conversions.
+*/
+static int getDigits(const char *zDate, const char *zFormat, ...){
+  /* The aMx[] array translates the 3rd character of each format
+  ** spec into a max size:    a   b   c   d   e      f */
+  static const u16 aMx[] = { 12, 14, 24, 31, 59, 14712 };
+  va_list ap;
+  int cnt = 0;
+  char nextC;
+  va_start(ap, zFormat);
+  do{
+    char N = zFormat[0] - '0';
+    char min = zFormat[1] - '0';
+    int val = 0;
+    u16 max;
+
+    assert( zFormat[2]>='a' && zFormat[2]<='f' );
+    max = aMx[zFormat[2] - 'a'];
+    nextC = zFormat[3];
+    val = 0;
+    while( N-- ){
+      if( !sqlite3Isdigit(*zDate) ){
+        goto end_getDigits;
+      }
+      val = val*10 + *zDate - '0';
+      zDate++;
+    }
+    if( val<(int)min || val>(int)max || (nextC!=0 && nextC!=*zDate) ){
+      goto end_getDigits;
+    }
+    *va_arg(ap,int*) = val;
+    zDate++;
+    cnt++;
+    zFormat += 4;
+  }while( nextC );
+end_getDigits:
+  va_end(ap);
+  return cnt;
+}
+
+/*
+** Parse a timezone extension on the end of a date-time.
+** The extension is of the form:
+**
+**        (+/-)HH:MM
+**
+** Or the "zulu" notation:
+**
+**        Z
+**
+** If the parse is successful, write the number of minutes
+** of change in p->tz and return 0.  If a parser error occurs,
+** return non-zero.
+**
+** A missing specifier is not considered an error.
+*/
+static int parseTimezone(const char *zDate, DateTime *p){
+  int sgn = 0;
+  int nHr, nMn;
+  int c;
+  while( sqlite3Isspace(*zDate) ){ zDate++; }
+  p->tz = 0;
+  c = *zDate;
+  if( c=='-' ){
+    sgn = -1;
+  }else if( c=='+' ){
+    sgn = +1;
+  }else if( c=='Z' || c=='z' ){
+    zDate++;
+    p->isLocal = 0;
+    p->isUtc = 1;
+    goto zulu_time;
+  }else{
+    return c!=0;
+  }
+  zDate++;
+  if( getDigits(zDate, "20b:20e", &nHr, &nMn)!=2 ){
+    return 1;
+  }
+  zDate += 5;
+  p->tz = sgn*(nMn + nHr*60);
+zulu_time:
+  while( sqlite3Isspace(*zDate) ){ zDate++; }
+  return *zDate!=0;
+}
+
+/*
+** Parse times of the form HH:MM or HH:MM:SS or HH:MM:SS.FFFF.
+** The HH, MM, and SS must each be exactly 2 digits.  The
+** fractional seconds FFFF can be one or more digits.
+**
+** Return 1 if there is a parsing error and 0 on success.
+*/
+static int parseHhMmSs(const char *zDate, DateTime *p){
+  int h, m, s;
+  double ms = 0.0;
+  if( getDigits(zDate, "20c:20e", &h, &m)!=2 ){
+    return 1;
+  }
+  zDate += 5;
+  if( *zDate==':' ){
+    zDate++;
+    if( getDigits(zDate, "20e", &s)!=1 ){
+      return 1;
+    }
+    zDate += 2;
+    if( *zDate=='.' && sqlite3Isdigit(zDate[1]) ){
+      double rScale = 1.0;
+      zDate++;
+      while( sqlite3Isdigit(*zDate) ){
+        ms = ms*10.0 + *zDate - '0';
+        rScale *= 10.0;
+        zDate++;
+      }
+      ms /= rScale;
+      /* Truncate to avoid problems with sub-milliseconds
+      ** rounding. https://sqlite.org/forum/forumpost/766a2c9231 */
+      if( ms>0.999 ) ms = 0.999;
+    }
+  }else{
+    s = 0;
+  }
+  p->validJD = 0;
+  p->rawS = 0;
+  p->validHMS = 1;
+  p->h = h;
+  p->m = m;
+  p->s = s + ms;
+  if( parseTimezone(zDate, p) ) return 1;
+  return 0;
+}
+
+/*
+** Put the DateTime object into its error state.
+*/
+static void datetimeError(DateTime *p){
+  memset(p, 0, sizeof(*p));
+  p->isError = 1;
+}
+
+/*
+** Convert from YYYY-MM-DD HH:MM:SS to julian day.  We always assume
+** that the YYYY-MM-DD is according to the Gregorian calendar.
+**
+** Reference:  Meeus page 61
+*/
+static void computeJD(DateTime *p){
+  int Y, M, D, A, B, X1, X2;
+
+  if( p->validJD ) return;
+  if( p->validYMD ){
+    Y = p->Y;
+    M = p->M;
+    D = p->D;
+  }else{
+    Y = 2000;  /* If no YMD specified, assume 2000-Jan-01 */
+    M = 1;
+    D = 1;
+  }
+  if( Y<-4713 || Y>9999 || p->rawS ){
+    datetimeError(p);
+    return;
+  }
+  if( M<=2 ){
+    Y--;
+    M += 12;
+  }
+  A = (Y+4800)/100;
+  B = 38 - A + (A/4);
+  X1 = 36525*(Y+4716)/100;
+  X2 = 306001*(M+1)/10000;
+  p->iJD = (sqlite3_int64)((X1 + X2 + D + B - 1524.5 ) * 86400000);
+  p->validJD = 1;
+  if( p->validHMS ){
+    p->iJD += p->h*3600000 + p->m*60000 + (sqlite3_int64)(p->s*1000 + 0.5);
+    if( p->tz ){
+      p->iJD -= p->tz*60000;
+      p->validYMD = 0;
+      p->validHMS = 0;
+      p->tz = 0;
+      p->isUtc = 1;
+      p->isLocal = 0;
+    }
+  }
+}
+
+/*
+** Given the YYYY-MM-DD information current in p, determine if there
+** is day-of-month overflow and set nFloor to the number of days that
+** would need to be subtracted from the date in order to bring the
+** date back to the end of the month.
+*/
+static void computeFloor(DateTime *p){
+  assert( p->validYMD || p->isError );
+  assert( p->D>=0 && p->D<=31 );
+  assert( p->M>=0 && p->M<=12 );
+  if( p->D<=28 ){
+    p->nFloor = 0;
+  }else if( (1<<p->M) & 0x15aa ){
+    p->nFloor = 0;
+  }else if( p->M!=2 ){
+    p->nFloor = (p->D==31);
+  }else if( p->Y%4!=0 || (p->Y%100==0 && p->Y%400!=0) ){
+    p->nFloor = p->D - 28;
+  }else{
+    p->nFloor = p->D - 29;
+  }
+}
+
+/*
+** Parse dates of the form
+**
+**     YYYY-MM-DD HH:MM:SS.FFF
+**     YYYY-MM-DD HH:MM:SS
+**     YYYY-MM-DD HH:MM
+**     YYYY-MM-DD
+**
+** Write the result into the DateTime structure and return 0
+** on success and 1 if the input string is not a well-formed
+** date.
+*/
+static int parseYyyyMmDd(const char *zDate, DateTime *p){
+  int Y, M, D, neg;
+
+  if( zDate[0]=='-' ){
+    zDate++;
+    neg = 1;
+  }else{
+    neg = 0;
+  }
+  if( getDigits(zDate, "40f-21a-21d", &Y, &M, &D)!=3 ){
+    return 1;
+  }
+  zDate += 10;
+  while( sqlite3Isspace(*zDate) || 'T'==*(u8*)zDate ){ zDate++; }
+  if( parseHhMmSs(zDate, p)==0 ){
+    /* We got the time */
+  }else if( *zDate==0 ){
+    p->validHMS = 0;
+  }else{
+    return 1;
+  }
+  p->validJD = 0;
+  p->validYMD = 1;
+  p->Y = neg ? -Y : Y;
+  p->M = M;
+  p->D = D;
+  computeFloor(p);
+  if( p->tz ){
+    computeJD(p);
+  }
+  return 0;
+}
+
+
+static void clearYMD_HMS_TZ(DateTime *p);  /* Forward declaration */
+
+/*
+** Set the time to the current time reported by the VFS.
+**
+** Return the number of errors.
+*/
+static int setDateTimeToCurrent(sqlite3_context *context, DateTime *p){
+  p->iJD = sqlite3StmtCurrentTime(context);
+  if( p->iJD>0 ){
+    p->validJD = 1;
+    p->isUtc = 1;
+    p->isLocal = 0;
+    clearYMD_HMS_TZ(p);
+    return 0;
+  }else{
+    return 1;
+  }
+}
+
+/*
+** Input "r" is a numeric quantity which might be a julian day number,
+** or the number of seconds since 1970.  If the value if r is within
+** range of a julian day number, install it as such and set validJD.
+** If the value is a valid unix timestamp, put it in p->s and set p->rawS.
+*/
+static void setRawDateNumber(DateTime *p, double r){
+  p->s = r;
+  p->rawS = 1;
+  if( r>=0.0 && r<5373484.5 ){
+    p->iJD = (sqlite3_int64)(r*86400000.0 + 0.5);
+    p->validJD = 1;
+  }
+}
+
+/*
+** Attempt to parse the given string into a julian day number.  Return
+** the number of errors.
+**
+** The following are acceptable forms for the input string:
+**
+**      YYYY-MM-DD HH:MM:SS.FFF  +/-HH:MM
+**      DDDD.DD
+**      now
+**
+** In the first form, the +/-HH:MM is always optional.  The fractional
+** seconds extension (the ".FFF") is optional.  The seconds portion
+** (":SS.FFF") is option.  The year and date can be omitted as long
+** as there is a time string.  The time string can be omitted as long
+** as there is a year and date.
+*/
+static int parseDateOrTime(
+  sqlite3_context *context,
+  const char *zDate,
+  DateTime *p
+){
+  double r;
+  if( parseYyyyMmDd(zDate,p)==0 ){
+    return 0;
+  }else if( parseHhMmSs(zDate, p)==0 ){
+    return 0;
+  }else if( sqlite3StrICmp(zDate,"now")==0 && sqlite3NotPureFunc(context) ){
+    return setDateTimeToCurrent(context, p);
+  }else if( sqlite3AtoF(zDate, &r, sqlite3Strlen30(zDate), SQLITE_UTF8)>0 ){
+    setRawDateNumber(p, r);
+    return 0;
+  }else if( (sqlite3StrICmp(zDate,"subsec")==0
+             || sqlite3StrICmp(zDate,"subsecond")==0)
+           && sqlite3NotPureFunc(context) ){
+    p->useSubsec = 1;
+    return setDateTimeToCurrent(context, p);
+  }
+  return 1;
+}
+
+/* The julian day number for 9999-12-31 23:59:59.999 is 5373484.4999999.
+** Multiplying this by 86400000 gives 464269060799999 as the maximum value
+** for DateTime.iJD.
+**
+** But some older compilers (ex: gcc 4.2.1 on older Macs) cannot deal with
+** such a large integer literal, so we have to encode it.
+*/
+#define INT_464269060799999  ((((i64)0x1a640)<<32)|0x1072fdff)
+
+/*
+** Return TRUE if the given julian day number is within range.
+**
+** The input is the JulianDay times 86400000.
+*/
+static int validJulianDay(sqlite3_int64 iJD){
+  return iJD>=0 && iJD<=INT_464269060799999;
+}
+
+/*
+** Compute the Year, Month, and Day from the julian day number.
+*/
+static void computeYMD(DateTime *p){
+  int Z, alpha, A, B, C, D, E, X1;
+  if( p->validYMD ) return;
+  if( !p->validJD ){
+    p->Y = 2000;
+    p->M = 1;
+    p->D = 1;
+  }else if( !validJulianDay(p->iJD) ){
+    datetimeError(p);
+    return;
+  }else{
+    Z = (int)((p->iJD + 43200000)/86400000);
+    alpha = (int)((Z + 32044.75)/36524.25) - 52;
+    A = Z + 1 + alpha - ((alpha+100)/4) + 25;
+    B = A + 1524;
+    C = (int)((B - 122.1)/365.25);
+    D = (36525*(C&32767))/100;
+    E = (int)((B-D)/30.6001);
+    X1 = (int)(30.6001*E);
+    p->D = B - D - X1;
+    p->M = E<14 ? E-1 : E-13;
+    p->Y = p->M>2 ? C - 4716 : C - 4715;
+  }
+  p->validYMD = 1;
+}
+
+/*
+** Compute the Hour, Minute, and Seconds from the julian day number.
+*/
+static void computeHMS(DateTime *p){
+  int day_ms, day_min; /* milliseconds, minutes into the day */
+  if( p->validHMS ) return;
+  computeJD(p);
+  day_ms = (int)((p->iJD + 43200000) % 86400000);
+  p->s = (day_ms % 60000)/1000.0;
+  day_min = day_ms/60000;
+  p->m = day_min % 60;
+  p->h = day_min / 60;
+  p->rawS = 0;
+  p->validHMS = 1;
+}
+
+/*
+** Compute both YMD and HMS
+*/
+static void computeYMD_HMS(DateTime *p){
+  computeYMD(p);
+  computeHMS(p);
+}
+
+/*
+** Clear the YMD and HMS and the TZ
+*/
+static void clearYMD_HMS_TZ(DateTime *p){
+  p->validYMD = 0;
+  p->validHMS = 0;
+  p->tz = 0;
+}
+
+#ifndef SQLITE_OMIT_LOCALTIME
+/*
+** On recent Windows platforms, the localtime_s() function is available
+** as part of the "Secure CRT". It is essentially equivalent to
+** localtime_r() available under most POSIX platforms, except that the
+** order of the parameters is reversed.
+**
+** See http://msdn.microsoft.com/en-us/library/a442x3ye(VS.80).aspx.
+**
+** If the user has not indicated to use localtime_r() or localtime_s()
+** already, check for an MSVC build environment that provides
+** localtime_s().
+*/
+#if !HAVE_LOCALTIME_R && !HAVE_LOCALTIME_S \
+    && defined(_MSC_VER) && defined(_CRT_INSECURE_DEPRECATE)
+#undef  HAVE_LOCALTIME_S
+#define HAVE_LOCALTIME_S 1
+#endif
+
+/*
+** The following routine implements the rough equivalent of localtime_r()
+** using whatever operating-system specific localtime facility that
+** is available.  This routine returns 0 on success and
+** non-zero on any kind of error.
+**
+** If the sqlite3GlobalConfig.bLocaltimeFault variable is non-zero then this
+** routine will always fail.  If bLocaltimeFault is nonzero and
+** sqlite3GlobalConfig.xAltLocaltime is not NULL, then xAltLocaltime() is
+** invoked in place of the OS-defined localtime() function.
+**
+** EVIDENCE-OF: R-62172-00036 In this implementation, the standard C
+** library function localtime_r() is used to assist in the calculation of
+** local time.
+*/
+static int osLocaltime(time_t *t, struct tm *pTm){
+  int rc;
+#if !HAVE_LOCALTIME_R && !HAVE_LOCALTIME_S
+  struct tm *pX;
+#if SQLITE_THREADSAFE>0
+  sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+  sqlite3_mutex_enter(mutex);
+  pX = localtime(t);
+#ifndef SQLITE_UNTESTABLE
+  if( sqlite3GlobalConfig.bLocaltimeFault ){
+    if( sqlite3GlobalConfig.xAltLocaltime!=0
+     && 0==sqlite3GlobalConfig.xAltLocaltime((const void*)t,(void*)pTm)
+    ){
+      pX = pTm;
+    }else{
+      pX = 0;
+    }
+  }
+#endif
+  if( pX ) *pTm = *pX;
+#if SQLITE_THREADSAFE>0
+  sqlite3_mutex_leave(mutex);
+#endif
+  rc = pX==0;
+#else
+#ifndef SQLITE_UNTESTABLE
+  if( sqlite3GlobalConfig.bLocaltimeFault ){
+    if( sqlite3GlobalConfig.xAltLocaltime!=0 ){
+      return sqlite3GlobalConfig.xAltLocaltime((const void*)t,(void*)pTm);
+    }else{
+      return 1;
+    }
+  }
+#endif
+#if HAVE_LOCALTIME_R
+  rc = localtime_r(t, pTm)==0;
+#else
+  rc = localtime_s(pTm, t);
+#endif /* HAVE_LOCALTIME_R */
+#endif /* HAVE_LOCALTIME_R || HAVE_LOCALTIME_S */
+  return rc;
+}
+#endif /* SQLITE_OMIT_LOCALTIME */
+
+
+#ifndef SQLITE_OMIT_LOCALTIME
+/*
+** Assuming the input DateTime is UTC, move it to its localtime equivalent.
+*/
+static int toLocaltime(
+  DateTime *p,                   /* Date at which to calculate offset */
+  sqlite3_context *pCtx          /* Write error here if one occurs */
+){
+  time_t t;
+  struct tm sLocal;
+  int iYearDiff;
+
+  /* Initialize the contents of sLocal to avoid a compiler warning. */
+  memset(&sLocal, 0, sizeof(sLocal));
+
+  computeJD(p);
+  if( p->iJD<2108667600*(i64)100000 /* 1970-01-01 */
+   || p->iJD>2130141456*(i64)100000 /* 2038-01-18 */
+  ){
+    /* EVIDENCE-OF: R-55269-29598 The localtime_r() C function normally only
+    ** works for years between 1970 and 2037. For dates outside this range,
+    ** SQLite attempts to map the year into an equivalent year within this
+    ** range, do the calculation, then map the year back.
+    */
+    DateTime x = *p;
+    computeYMD_HMS(&x);
+    iYearDiff = (2000 + x.Y%4) - x.Y;
+    x.Y += iYearDiff;
+    x.validJD = 0;
+    computeJD(&x);
+    t = (time_t)(x.iJD/1000 -  21086676*(i64)10000);
+  }else{
+    iYearDiff = 0;
+    t = (time_t)(p->iJD/1000 -  21086676*(i64)10000);
+  }
+  if( osLocaltime(&t, &sLocal) ){
+    sqlite3_result_error(pCtx, "local time unavailable", -1);
+    return SQLITE_ERROR;
+  }
+  p->Y = sLocal.tm_year + 1900 - iYearDiff;
+  p->M = sLocal.tm_mon + 1;
+  p->D = sLocal.tm_mday;
+  p->h = sLocal.tm_hour;
+  p->m = sLocal.tm_min;
+  p->s = sLocal.tm_sec + (p->iJD%1000)*0.001;
+  p->validYMD = 1;
+  p->validHMS = 1;
+  p->validJD = 0;
+  p->rawS = 0;
+  p->tz = 0;
+  p->isError = 0;
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_LOCALTIME */
+
+/*
+** The following table defines various date transformations of the form
+**
+**            'NNN days'
+**
+** Where NNN is an arbitrary floating-point number and "days" can be one
+** of several units of time.
+*/
+static const struct {
+  u8 nName;           /* Length of the name */
+  char zName[7];      /* Name of the transformation */
+  float rLimit;       /* Maximum NNN value for this transform */
+  float rXform;       /* Constant used for this transform */
+} aXformType[] = {
+  /* 0 */ { 6, "second",   4.6427e+14,         1.0  },
+  /* 1 */ { 6, "minute",   7.7379e+12,        60.0  },
+  /* 2 */ { 4, "hour",     1.2897e+11,      3600.0  },
+  /* 3 */ { 3, "day",      5373485.0,      86400.0  },
+  /* 4 */ { 5, "month",    176546.0,     2592000.0  },
+  /* 5 */ { 4, "year",     14713.0,     31536000.0  },
+};
+
+/*
+** If the DateTime p is raw number, try to figure out if it is
+** a julian day number of a unix timestamp.  Set the p value
+** appropriately.
+*/
+static void autoAdjustDate(DateTime *p){
+  if( !p->rawS || p->validJD ){
+    p->rawS = 0;
+  }else if( p->s>=-21086676*(i64)10000        /* -4713-11-24 12:00:00 */
+         && p->s<=(25340230*(i64)10000)+799   /*  9999-12-31 23:59:59 */
+  ){
+    double r = p->s*1000.0 + 210866760000000.0;
+    clearYMD_HMS_TZ(p);
+    p->iJD = (sqlite3_int64)(r + 0.5);
+    p->validJD = 1;
+    p->rawS = 0;
+  }
+}
+
+/*
+** Process a modifier to a date-time stamp.  The modifiers are
+** as follows:
+**
+**     NNN days
+**     NNN hours
+**     NNN minutes
+**     NNN.NNNN seconds
+**     NNN months
+**     NNN years
+**     +/-YYYY-MM-DD HH:MM:SS.SSS
+**     ceiling
+**     floor
+**     start of month
+**     start of year
+**     start of week
+**     start of day
+**     weekday N
+**     unixepoch
+**     auto
+**     localtime
+**     utc
+**     subsec
+**     subsecond
+**
+** Return 0 on success and 1 if there is any kind of error. If the error
+** is in a system call (i.e. localtime()), then an error message is written
+** to context pCtx. If the error is an unrecognized modifier, no error is
+** written to pCtx.
+*/
+static int parseModifier(
+  sqlite3_context *pCtx,      /* Function context */
+  const char *z,              /* The text of the modifier */
+  int n,                      /* Length of zMod in bytes */
+  DateTime *p,                /* The date/time value to be modified */
+  int idx                     /* Parameter index of the modifier */
+){
+  int rc = 1;
+  double r;
+  switch(sqlite3UpperToLower[(u8)z[0]] ){
+    case 'a': {
+      /*
+      **    auto
+      **
+      ** If rawS is available, then interpret as a julian day number, or
+      ** a unix timestamp, depending on its magnitude.
+      */
+      if( sqlite3_stricmp(z, "auto")==0 ){
+        if( idx>1 ) return 1; /* IMP: R-33611-57934 */
+        autoAdjustDate(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 'c': {
+      /*
+      **    ceiling
+      **
+      ** Resolve day-of-month overflow by rolling forward into the next
+      ** month.  As this is the default action, this modifier is really
+      ** a no-op that is only included for symmetry.  See "floor".
+      */
+      if( sqlite3_stricmp(z, "ceiling")==0 ){
+        computeJD(p);
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+        p->nFloor = 0;
+      }
+      break;
+    }
+    case 'f': {
+      /*
+      **    floor
+      **
+      ** Resolve day-of-month overflow by rolling back to the end of the
+      ** previous month.
+      */
+      if( sqlite3_stricmp(z, "floor")==0 ){
+        computeJD(p);
+        p->iJD -= p->nFloor*86400000;
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 'j': {
+      /*
+      **    julianday
+      **
+      ** Always interpret the prior number as a julian-day value.  If this
+      ** is not the first modifier, or if the prior argument is not a numeric
+      ** value in the allowed range of julian day numbers understood by
+      ** SQLite (0..5373484.5) then the result will be NULL.
+      */
+      if( sqlite3_stricmp(z, "julianday")==0 ){
+        if( idx>1 ) return 1;  /* IMP: R-31176-64601 */
+        if( p->validJD && p->rawS ){
+          rc = 0;
+          p->rawS = 0;
+        }
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_LOCALTIME
+    case 'l': {
+      /*    localtime
+      **
+      ** Assuming the current time value is UTC (a.k.a. GMT), shift it to
+      ** show local time.
+      */
+      if( sqlite3_stricmp(z, "localtime")==0 && sqlite3NotPureFunc(pCtx) ){
+        rc = p->isLocal ? SQLITE_OK : toLocaltime(p, pCtx);
+        p->isUtc = 0;
+        p->isLocal = 1;
+      }
+      break;
+    }
+#endif
+    case 'u': {
+      /*
+      **    unixepoch
+      **
+      ** Treat the current value of p->s as the number of
+      ** seconds since 1970.  Convert to a real julian day number.
+      */
+      if( sqlite3_stricmp(z, "unixepoch")==0 && p->rawS ){
+        if( idx>1 ) return 1;  /* IMP: R-49255-55373 */
+        r = p->s*1000.0 + 210866760000000.0;
+        if( r>=0.0 && r<464269060800000.0 ){
+          clearYMD_HMS_TZ(p);
+          p->iJD = (sqlite3_int64)(r + 0.5);
+          p->validJD = 1;
+          p->rawS = 0;
+          rc = 0;
+        }
+      }
+#ifndef SQLITE_OMIT_LOCALTIME
+      else if( sqlite3_stricmp(z, "utc")==0 && sqlite3NotPureFunc(pCtx) ){
+        if( p->isUtc==0 ){
+          i64 iOrigJD;              /* Original localtime */
+          i64 iGuess;               /* Guess at the corresponding utc time */
+          int cnt = 0;              /* Safety to prevent infinite loop */
+          i64 iErr;                 /* Guess is off by this much */
+
+          computeJD(p);
+          iGuess = iOrigJD = p->iJD;
+          iErr = 0;
+          do{
+            DateTime new;
+            memset(&new, 0, sizeof(new));
+            iGuess -= iErr;
+            new.iJD = iGuess;
+            new.validJD = 1;
+            rc = toLocaltime(&new, pCtx);
+            if( rc ) return rc;
+            computeJD(&new);
+            iErr = new.iJD - iOrigJD;
+          }while( iErr && cnt++<3 );
+          memset(p, 0, sizeof(*p));
+          p->iJD = iGuess;
+          p->validJD = 1;
+          p->isUtc = 1;
+          p->isLocal = 0;
+        }
+        rc = SQLITE_OK;
+      }
+#endif
+      break;
+    }
+    case 'w': {
+      /*
+      **    weekday N
+      **
+      ** Move the date to the same time on the next occurrence of
+      ** weekday N where 0==Sunday, 1==Monday, and so forth.  If the
+      ** date is already on the appropriate weekday, this is a no-op.
+      */
+      if( sqlite3_strnicmp(z, "weekday ", 8)==0
+               && sqlite3AtoF(&z[8], &r, sqlite3Strlen30(&z[8]), SQLITE_UTF8)>0
+               && r>=0.0 && r<7.0 && (n=(int)r)==r ){
+        sqlite3_int64 Z;
+        computeYMD_HMS(p);
+        p->tz = 0;
+        p->validJD = 0;
+        computeJD(p);
+        Z = ((p->iJD + 129600000)/86400000) % 7;
+        if( Z>n ) Z -= 7;
+        p->iJD += (n - Z)*86400000;
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 's': {
+      /*
+      **    start of TTTTT
+      **
+      ** Move the date backwards to the beginning of the current day,
+      ** or month or year.
+      **
+      **    subsecond
+      **    subsec
+      **
+      ** Show subsecond precision in the output of datetime() and
+      ** unixepoch() and strftime('%s').
+      */
+      if( sqlite3_strnicmp(z, "start of ", 9)!=0 ){
+        if( sqlite3_stricmp(z, "subsec")==0
+         || sqlite3_stricmp(z, "subsecond")==0
+        ){
+          p->useSubsec = 1;
+          rc = 0;
+        }
+        break;
+      }
+      if( !p->validJD && !p->validYMD && !p->validHMS ) break;
+      z += 9;
+      computeYMD(p);
+      p->validHMS = 1;
+      p->h = p->m = 0;
+      p->s = 0.0;
+      p->rawS = 0;
+      p->tz = 0;
+      p->validJD = 0;
+      if( sqlite3_stricmp(z,"month")==0 ){
+        p->D = 1;
+        rc = 0;
+      }else if( sqlite3_stricmp(z,"year")==0 ){
+        p->M = 1;
+        p->D = 1;
+        rc = 0;
+      }else if( sqlite3_stricmp(z,"day")==0 ){
+        rc = 0;
+      }
+      break;
+    }
+    case '+':
+    case '-':
+    case '0':
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+    case '8':
+    case '9': {
+      double rRounder;
+      int i;
+      int Y,M,D,h,m,x;
+      const char *z2 = z;
+      char z0 = z[0];
+      for(n=1; z[n]; n++){
+        if( z[n]==':' ) break;
+        if( sqlite3Isspace(z[n]) ) break;
+        if( z[n]=='-' ){
+          if( n==5 && getDigits(&z[1], "40f", &Y)==1 ) break;
+          if( n==6 && getDigits(&z[1], "50f", &Y)==1 ) break;
+        }
+      }
+      if( sqlite3AtoF(z, &r, n, SQLITE_UTF8)<=0 ){
+        assert( rc==1 );
+        break;
+      }
+      if( z[n]=='-' ){
+        /* A modifier of the form (+|-)YYYY-MM-DD adds or subtracts the
+        ** specified number of years, months, and days.  MM is limited to
+        ** the range 0-11 and DD is limited to 0-30.
+        */
+        if( z0!='+' && z0!='-' ) break;  /* Must start with +/- */
+        if( n==5 ){
+          if( getDigits(&z[1], "40f-20a-20d", &Y, &M, &D)!=3 ) break;
+        }else{
+          assert( n==6 );
+          if( getDigits(&z[1], "50f-20a-20d", &Y, &M, &D)!=3 ) break;
+          z++;
+        }
+        if( M>=12 ) break;                   /* M range 0..11 */
+        if( D>=31 ) break;                   /* D range 0..30 */
+        computeYMD_HMS(p);
+        p->validJD = 0;
+        if( z0=='-' ){
+          p->Y -= Y;
+          p->M -= M;
+          D = -D;
+        }else{
+          p->Y += Y;
+          p->M += M;
+        }
+        x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
+        p->Y += x;
+        p->M -= x*12;
+        computeFloor(p);
+        computeJD(p);
+        p->validHMS = 0;
+        p->validYMD = 0;
+        p->iJD += (i64)D*86400000;
+        if( z[11]==0 ){
+          rc = 0;
+          break;
+        }
+        if( sqlite3Isspace(z[11])
+         && getDigits(&z[12], "20c:20e", &h, &m)==2
+        ){
+          z2 = &z[12];
+          n = 2;
+        }else{
+          break;
+        }
+      }
+      if( z2[n]==':' ){
+        /* A modifier of the form (+|-)HH:MM:SS.FFF adds (or subtracts) the
+        ** specified number of hours, minutes, seconds, and fractional seconds
+        ** to the time.  The ".FFF" may be omitted.  The ":SS.FFF" may be
+        ** omitted.
+        */
+
+        DateTime tx;
+        sqlite3_int64 day;
+        if( !sqlite3Isdigit(*z2) ) z2++;
+        memset(&tx, 0, sizeof(tx));
+        if( parseHhMmSs(z2, &tx) ) break;
+        computeJD(&tx);
+        tx.iJD -= 43200000;
+        day = tx.iJD/86400000;
+        tx.iJD -= day*86400000;
+        if( z0=='-' ) tx.iJD = -tx.iJD;
+        computeJD(p);
+        clearYMD_HMS_TZ(p);
+        p->iJD += tx.iJD;
+        rc = 0;
+        break;
+      }
+
+      /* If control reaches this point, it means the transformation is
+      ** one of the forms like "+NNN days".  */
+      z += n;
+      while( sqlite3Isspace(*z) ) z++;
+      n = sqlite3Strlen30(z);
+      if( n<3 || n>10 ) break;
+      if( sqlite3UpperToLower[(u8)z[n-1]]=='s' ) n--;
+      computeJD(p);
+      assert( rc==1 );
+      rRounder = r<0 ? -0.5 : +0.5;
+      p->nFloor = 0;
+      for(i=0; i<ArraySize(aXformType); i++){
+        if( aXformType[i].nName==n
+         && sqlite3_strnicmp(aXformType[i].zName, z, n)==0
+         && r>-aXformType[i].rLimit && r<aXformType[i].rLimit
+        ){
+          switch( i ){
+            case 4: { /* Special processing to add months */
+              assert( strcmp(aXformType[4].zName,"month")==0 );
+              computeYMD_HMS(p);
+              p->M += (int)r;
+              x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
+              p->Y += x;
+              p->M -= x*12;
+              computeFloor(p);
+              p->validJD = 0;
+              r -= (int)r;
+              break;
+            }
+            case 5: { /* Special processing to add years */
+              int y = (int)r;
+              assert( strcmp(aXformType[5].zName,"year")==0 );
+              computeYMD_HMS(p);
+              assert( p->M>=0 && p->M<=12 );
+              p->Y += y;
+              computeFloor(p);
+              p->validJD = 0;
+              r -= (int)r;
+              break;
+            }
+          }
+          computeJD(p);
+          p->iJD += (sqlite3_int64)(r*1000.0*aXformType[i].rXform + rRounder);
+          rc = 0;
+          break;
+        }
+      }
+      clearYMD_HMS_TZ(p);
+      break;
+    }
+    default: {
+      break;
+    }
+  }
+  return rc;
+}
+
+/*
+** Process time function arguments.  argv[0] is a date-time stamp.
+** argv[1] and following are modifiers.  Parse them all and write
+** the resulting time into the DateTime structure p.  Return 0
+** on success and 1 if there are any errors.
+**
+** If there are zero parameters (if even argv[0] is undefined)
+** then assume a default value of "now" for argv[0].
+*/
+static int isDate(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv,
+  DateTime *p
+){
+  int i, n;
+  const unsigned char *z;
+  int eType;
+  memset(p, 0, sizeof(*p));
+  if( argc==0 ){
+    if( !sqlite3NotPureFunc(context) ) return 1;
+    return setDateTimeToCurrent(context, p);
+  }
+  if( (eType = sqlite3_value_type(argv[0]))==SQLITE_FLOAT
+                   || eType==SQLITE_INTEGER ){
+    setRawDateNumber(p, sqlite3_value_double(argv[0]));
+  }else{
+    z = sqlite3_value_text(argv[0]);
+    if( !z || parseDateOrTime(context, (char*)z, p) ){
+      return 1;
+    }
+  }
+  for(i=1; i<argc; i++){
+    z = sqlite3_value_text(argv[i]);
+    n = sqlite3_value_bytes(argv[i]);
+    if( z==0 || parseModifier(context, (char*)z, n, p, i) ) return 1;
+  }
+  computeJD(p);
+  if( p->isError || !validJulianDay(p->iJD) ) return 1;
+  if( argc==1 && p->validYMD && p->D>28 ){
+    /* Make sure a YYYY-MM-DD is normalized.
+    ** Example: 2023-02-31 -> 2023-03-03 */
+    assert( p->validJD );
+    p->validYMD = 0;
+  }
+  return 0;
+}
+
+
+/*
+** The following routines implement the various date and time functions
+** of SQLite.
+*/
+
+/*
+**    julianday( TIMESTRING, MOD, MOD, ...)
+**
+** Return the julian day number of the date specified in the arguments
+*/
+static void juliandayFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    computeJD(&x);
+    sqlite3_result_double(context, x.iJD/86400000.0);
+  }
+}
+
+/*
+**    unixepoch( TIMESTRING, MOD, MOD, ...)
+**
+** Return the number of seconds (including fractional seconds) since
+** the unix epoch of 1970-01-01 00:00:00 GMT.
+*/
+static void unixepochFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    computeJD(&x);
+    if( x.useSubsec ){
+      sqlite3_result_double(context, (x.iJD - 21086676*(i64)10000000)/1000.0);
+    }else{
+      sqlite3_result_int64(context, x.iJD/1000 - 21086676*(i64)10000);
+    }
+  }
+}
+
+/*
+**    datetime( TIMESTRING, MOD, MOD, ...)
+**
+** Return YYYY-MM-DD HH:MM:SS
+*/
+static void datetimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    int Y, s, n;
+    char zBuf[32];
+    computeYMD_HMS(&x);
+    Y = x.Y;
+    if( Y<0 ) Y = -Y;
+    zBuf[1] = '0' + (Y/1000)%10;
+    zBuf[2] = '0' + (Y/100)%10;
+    zBuf[3] = '0' + (Y/10)%10;
+    zBuf[4] = '0' + (Y)%10;
+    zBuf[5] = '-';
+    zBuf[6] = '0' + (x.M/10)%10;
+    zBuf[7] = '0' + (x.M)%10;
+    zBuf[8] = '-';
+    zBuf[9] = '0' + (x.D/10)%10;
+    zBuf[10] = '0' + (x.D)%10;
+    zBuf[11] = ' ';
+    zBuf[12] = '0' + (x.h/10)%10;
+    zBuf[13] = '0' + (x.h)%10;
+    zBuf[14] = ':';
+    zBuf[15] = '0' + (x.m/10)%10;
+    zBuf[16] = '0' + (x.m)%10;
+    zBuf[17] = ':';
+    if( x.useSubsec ){
+      s = (int)(1000.0*x.s + 0.5);
+      zBuf[18] = '0' + (s/10000)%10;
+      zBuf[19] = '0' + (s/1000)%10;
+      zBuf[20] = '.';
+      zBuf[21] = '0' + (s/100)%10;
+      zBuf[22] = '0' + (s/10)%10;
+      zBuf[23] = '0' + (s)%10;
+      zBuf[24] = 0;
+      n = 24;
+    }else{
+      s = (int)x.s;
+      zBuf[18] = '0' + (s/10)%10;
+      zBuf[19] = '0' + (s)%10;
+      zBuf[20] = 0;
+      n = 20;
+    }
+    if( x.Y<0 ){
+      zBuf[0] = '-';
+      sqlite3_result_text(context, zBuf, n, SQLITE_TRANSIENT);
+    }else{
+      sqlite3_result_text(context, &zBuf[1], n-1, SQLITE_TRANSIENT);
+    }
+  }
+}
+
+/*
+**    time( TIMESTRING, MOD, MOD, ...)
+**
+** Return HH:MM:SS
+*/
+static void timeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    int s, n;
+    char zBuf[16];
+    computeHMS(&x);
+    zBuf[0] = '0' + (x.h/10)%10;
+    zBuf[1] = '0' + (x.h)%10;
+    zBuf[2] = ':';
+    zBuf[3] = '0' + (x.m/10)%10;
+    zBuf[4] = '0' + (x.m)%10;
+    zBuf[5] = ':';
+    if( x.useSubsec ){
+      s = (int)(1000.0*x.s + 0.5);
+      zBuf[6] = '0' + (s/10000)%10;
+      zBuf[7] = '0' + (s/1000)%10;
+      zBuf[8] = '.';
+      zBuf[9] = '0' + (s/100)%10;
+      zBuf[10] = '0' + (s/10)%10;
+      zBuf[11] = '0' + (s)%10;
+      zBuf[12] = 0;
+      n = 12;
+    }else{
+      s = (int)x.s;
+      zBuf[6] = '0' + (s/10)%10;
+      zBuf[7] = '0' + (s)%10;
+      zBuf[8] = 0;
+      n = 8;
+    }
+    sqlite3_result_text(context, zBuf, n, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+**    date( TIMESTRING, MOD, MOD, ...)
+**
+** Return YYYY-MM-DD
+*/
+static void dateFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    int Y;
+    char zBuf[16];
+    computeYMD(&x);
+    Y = x.Y;
+    if( Y<0 ) Y = -Y;
+    zBuf[1] = '0' + (Y/1000)%10;
+    zBuf[2] = '0' + (Y/100)%10;
+    zBuf[3] = '0' + (Y/10)%10;
+    zBuf[4] = '0' + (Y)%10;
+    zBuf[5] = '-';
+    zBuf[6] = '0' + (x.M/10)%10;
+    zBuf[7] = '0' + (x.M)%10;
+    zBuf[8] = '-';
+    zBuf[9] = '0' + (x.D/10)%10;
+    zBuf[10] = '0' + (x.D)%10;
+    zBuf[11] = 0;
+    if( x.Y<0 ){
+      zBuf[0] = '-';
+      sqlite3_result_text(context, zBuf, 11, SQLITE_TRANSIENT);
+    }else{
+      sqlite3_result_text(context, &zBuf[1], 10, SQLITE_TRANSIENT);
+    }
+  }
+}
+
+/*
+** Compute the number of days after the most recent January 1.
+**
+** In other words, compute the zero-based day number for the
+** current year:
+**
+**   Jan01 = 0,  Jan02 = 1, ..., Jan31 = 30, Feb01 = 31, ...
+**   Dec31 = 364 or 365.
+*/
+static int daysAfterJan01(DateTime *pDate){
+  DateTime jan01 = *pDate;
+  assert( jan01.validYMD );
+  assert( jan01.validHMS );
+  assert( pDate->validJD );
+  jan01.validJD = 0;
+  jan01.M = 1;
+  jan01.D = 1;
+  computeJD(&jan01);
+  return (int)((pDate->iJD-jan01.iJD+43200000)/86400000);
+}
+
+/*
+** Return the number of days after the most recent Monday.
+**
+** In other words, return the day of the week according
+** to this code:
+**
+**   0=Monday, 1=Tuesday, 2=Wednesday, ..., 6=Sunday.
+*/
+static int daysAfterMonday(DateTime *pDate){
+  assert( pDate->validJD );
+  return (int)((pDate->iJD+43200000)/86400000) % 7;
+}
+
+/*
+** Return the number of days after the most recent Sunday.
+**
+** In other words, return the day of the week according
+** to this code:
+**
+**   0=Sunday, 1=Monday, 2=Tues, ..., 6=Saturday
+*/
+static int daysAfterSunday(DateTime *pDate){
+  assert( pDate->validJD );
+  return (int)((pDate->iJD+129600000)/86400000) % 7;
+}
+
+/*
+**    strftime( FORMAT, TIMESTRING, MOD, MOD, ...)
+**
+** Return a string described by FORMAT.  Conversions as follows:
+**
+**   %d  day of month  01-31
+**   %e  day of month  1-31
+**   %f  ** fractional seconds  SS.SSS
+**   %F  ISO date.  YYYY-MM-DD
+**   %G  ISO year corresponding to %V 0000-9999.
+**   %g  2-digit ISO year corresponding to %V 00-99
+**   %H  hour 00-24
+**   %k  hour  0-24  (leading zero converted to space)
+**   %I  hour 01-12
+**   %j  day of year 001-366
+**   %J  ** julian day number
+**   %l  hour  1-12  (leading zero converted to space)
+**   %m  month 01-12
+**   %M  minute 00-59
+**   %p  "am" or "pm"
+**   %P  "AM" or "PM"
+**   %R  time as HH:MM
+**   %s  seconds since 1970-01-01
+**   %S  seconds 00-59
+**   %T  time as HH:MM:SS
+**   %u  day of week 1-7  Monday==1, Sunday==7
+**   %w  day of week 0-6  Sunday==0, Monday==1
+**   %U  week of year 00-53  (First Sunday is start of week 01)
+**   %V  week of year 01-53  (First week containing Thursday is week 01)
+**   %W  week of year 00-53  (First Monday is start of week 01)
+**   %Y  year 0000-9999
+**   %%  %
+*/
+static void strftimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  size_t i,j;
+  sqlite3 *db;
+  const char *zFmt;
+  sqlite3_str sRes;
+
+
+  if( argc==0 ) return;
+  zFmt = (const char*)sqlite3_value_text(argv[0]);
+  if( zFmt==0 || isDate(context, argc-1, argv+1, &x) ) return;
+  db = sqlite3_context_db_handle(context);
+  sqlite3StrAccumInit(&sRes, 0, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
+
+  computeJD(&x);
+  computeYMD_HMS(&x);
+  for(i=j=0; zFmt[i]; i++){
+    char cf;
+    if( zFmt[i]!='%' ) continue;
+    if( j<i ) sqlite3_str_append(&sRes, zFmt+j, (int)(i-j));
+    i++;
+    j = i + 1;
+    cf = zFmt[i];
+    switch( cf ){
+      case 'd':  /* Fall thru */
+      case 'e': {
+        sqlite3_str_appendf(&sRes, cf=='d' ? "%02d" : "%2d", x.D);
+        break;
+      }
+      case 'f': {  /* Fractional seconds.  (Non-standard) */
+        double s = x.s;
+        if( NEVER(s>59.999) ) s = 59.999;
+        sqlite3_str_appendf(&sRes, "%06.3f", s);
+        break;
+      }
+      case 'F': {
+        sqlite3_str_appendf(&sRes, "%04d-%02d-%02d", x.Y, x.M, x.D);
+        break;
+      }
+      case 'G': /* Fall thru */
+      case 'g': {
+        DateTime y = x;
+        assert( y.validJD );
+        /* Move y so that it is the Thursday in the same week as x */
+        y.iJD += (3 - daysAfterMonday(&x))*86400000;
+        y.validYMD = 0;
+        computeYMD(&y);
+        if( cf=='g' ){
+          sqlite3_str_appendf(&sRes, "%02d", y.Y%100);
+        }else{
+          sqlite3_str_appendf(&sRes, "%04d", y.Y);
+        }
+        break;
+      }
+      case 'H':
+      case 'k': {
+        sqlite3_str_appendf(&sRes, cf=='H' ? "%02d" : "%2d", x.h);
+        break;
+      }
+      case 'I': /* Fall thru */
+      case 'l': {
+        int h = x.h;
+        if( h>12 ) h -= 12;
+        if( h==0 ) h = 12;
+        sqlite3_str_appendf(&sRes, cf=='I' ? "%02d" : "%2d", h);
+        break;
+      }
+      case 'j': {  /* Day of year.  Jan01==1, Jan02==2, and so forth */
+        sqlite3_str_appendf(&sRes,"%03d",daysAfterJan01(&x)+1);
+        break;
+      }
+      case 'J': {  /* Julian day number.  (Non-standard) */
+        sqlite3_str_appendf(&sRes,"%.16g",x.iJD/86400000.0);
+        break;
+      }
+      case 'm': {
+        sqlite3_str_appendf(&sRes,"%02d",x.M);
+        break;
+      }
+      case 'M': {
+        sqlite3_str_appendf(&sRes,"%02d",x.m);
+        break;
+      }
+      case 'p': /* Fall thru */
+      case 'P': {
+        if( x.h>=12 ){
+          sqlite3_str_append(&sRes, cf=='p' ? "PM" : "pm", 2);
+        }else{
+          sqlite3_str_append(&sRes, cf=='p' ? "AM" : "am", 2);
+        }
+        break;
+      }
+      case 'R': {
+        sqlite3_str_appendf(&sRes, "%02d:%02d", x.h, x.m);
+        break;
+      }
+      case 's': {
+        if( x.useSubsec ){
+          sqlite3_str_appendf(&sRes,"%.3f",
+                (x.iJD - 21086676*(i64)10000000)/1000.0);
+        }else{
+          i64 iS = (i64)(x.iJD/1000 - 21086676*(i64)10000);
+          sqlite3_str_appendf(&sRes,"%lld",iS);
+        }
+        break;
+      }
+      case 'S': {
+        sqlite3_str_appendf(&sRes,"%02d",(int)x.s);
+        break;
+      }
+      case 'T': {
+        sqlite3_str_appendf(&sRes,"%02d:%02d:%02d", x.h, x.m, (int)x.s);
+        break;
+      }
+      case 'u':    /* Day of week.  1 to 7.  Monday==1, Sunday==7 */
+      case 'w': {  /* Day of week.  0 to 6.  Sunday==0, Monday==1 */
+        char c = (char)daysAfterSunday(&x) + '0';
+        if( c=='0' && cf=='u' ) c = '7';
+        sqlite3_str_appendchar(&sRes, 1, c);
+        break;
+      }
+      case 'U': {  /* Week num. 00-53. First Sun of the year is week 01 */
+        sqlite3_str_appendf(&sRes,"%02d",
+              (daysAfterJan01(&x)-daysAfterSunday(&x)+7)/7);
+        break;
+      }
+      case 'V': {  /* Week num. 01-53. First week with a Thur is week 01 */
+        DateTime y = x;
+        /* Adjust y so that is the Thursday in the same week as x */
+        assert( y.validJD );
+        y.iJD += (3 - daysAfterMonday(&x))*86400000;
+        y.validYMD = 0;
+        computeYMD(&y);
+        sqlite3_str_appendf(&sRes,"%02d", daysAfterJan01(&y)/7+1);
+        break;
+      }
+      case 'W': {  /* Week num. 00-53. First Mon of the year is week 01 */
+        sqlite3_str_appendf(&sRes,"%02d",
+           (daysAfterJan01(&x)-daysAfterMonday(&x)+7)/7);
+        break;
+      }
+      case 'Y': {
+        sqlite3_str_appendf(&sRes,"%04d",x.Y);
+        break;
+      }
+      case '%': {
+        sqlite3_str_appendchar(&sRes, 1, '%');
+        break;
+      }
+      default: {
+        sqlite3_str_reset(&sRes);
+        return;
+      }
+    }
+  }
+  if( j<i ) sqlite3_str_append(&sRes, zFmt+j, (int)(i-j));
+  sqlite3ResultStrAccum(context, &sRes);
+}
+
+/*
+** current_time()
+**
+** This function returns the same value as time('now').
+*/
+static void ctimeFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  timeFunc(context, 0, 0);
+}
+
+/*
+** current_date()
+**
+** This function returns the same value as date('now').
+*/
+static void cdateFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  dateFunc(context, 0, 0);
+}
+
+/*
+** timediff(DATE1, DATE2)
+**
+** Return the amount of time that must be added to DATE2 in order to
+** convert it into DATE2.  The time difference format is:
+**
+**     +YYYY-MM-DD HH:MM:SS.SSS
+**
+** The initial "+" becomes "-" if DATE1 occurs before DATE2.  For
+** date/time values A and B, the following invariant should hold:
+**
+**     datetime(A) == (datetime(B, timediff(A,B))
+**
+** Both DATE arguments must be either a julian day number, or an
+** ISO-8601 string.  The unix timestamps are not supported by this
+** routine.
+*/
+static void timediffFunc(
+  sqlite3_context *context,
+  int NotUsed1,
+  sqlite3_value **argv
+){
+  char sign;
+  int Y, M;
+  DateTime d1, d2;
+  sqlite3_str sRes;
+  UNUSED_PARAMETER(NotUsed1);
+  if( isDate(context, 1, &argv[0], &d1) ) return;
+  if( isDate(context, 1, &argv[1], &d2) ) return;
+  computeYMD_HMS(&d1);
+  computeYMD_HMS(&d2);
+  if( d1.iJD>=d2.iJD ){
+    sign = '+';
+    Y = d1.Y - d2.Y;
+    if( Y ){
+      d2.Y = d1.Y;
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    M = d1.M - d2.M;
+    if( M<0 ){
+      Y--;
+      M += 12;
+    }
+    if( M!=0 ){
+      d2.M = d1.M;
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    while( d1.iJD<d2.iJD ){
+      M--;
+      if( M<0 ){
+        M = 11;
+        Y--;
+      }
+      d2.M--;
+      if( d2.M<1 ){
+        d2.M = 12;
+        d2.Y--;
+      }
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    d1.iJD -= d2.iJD;
+    d1.iJD += (u64)1486995408 * (u64)100000;
+  }else /* d1<d2 */{
+    sign = '-';
+    Y = d2.Y - d1.Y;
+    if( Y ){
+      d2.Y = d1.Y;
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    M = d2.M - d1.M;
+    if( M<0 ){
+      Y--;
+      M += 12;
+    }
+    if( M!=0 ){
+      d2.M = d1.M;
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    while( d1.iJD>d2.iJD ){
+      M--;
+      if( M<0 ){
+        M = 11;
+        Y--;
+      }
+      d2.M++;
+      if( d2.M>12 ){
+        d2.M = 1;
+        d2.Y++;
+      }
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    d1.iJD = d2.iJD - d1.iJD;
+    d1.iJD += (u64)1486995408 * (u64)100000;
+  }
+  clearYMD_HMS_TZ(&d1);
+  computeYMD_HMS(&d1);
+  sqlite3StrAccumInit(&sRes, 0, 0, 0, 100);
+  sqlite3_str_appendf(&sRes, "%c%04d-%02d-%02d %02d:%02d:%06.3f",
+       sign, Y, M, d1.D-1, d1.h, d1.m, d1.s);
+  sqlite3ResultStrAccum(context, &sRes);
+}
+
+
+/*
+** current_timestamp()
+**
+** This function returns the same value as datetime('now').
+*/
+static void ctimestampFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  datetimeFunc(context, 0, 0);
+}
+#endif /* !defined(SQLITE_OMIT_DATETIME_FUNCS) */
+
+#ifdef SQLITE_OMIT_DATETIME_FUNCS
+/*
+** If the library is compiled to omit the full-scale date and time
+** handling (to get a smaller binary), the following minimal version
+** of the functions current_time(), current_date() and current_timestamp()
+** are included instead. This is to support column declarations that
+** include "DEFAULT CURRENT_TIME" etc.
+**
+** This function uses the C-library functions time(), gmtime()
+** and strftime(). The format string to pass to strftime() is supplied
+** as the user-data for the function.
+*/
+static void currentTimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  time_t t;
+  char *zFormat = (char *)sqlite3_user_data(context);
+  sqlite3_int64 iT;
+  struct tm *pTm;
+  struct tm sNow;
+  char zBuf[20];
+
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+
+  iT = sqlite3StmtCurrentTime(context);
+  if( iT<=0 ) return;
+  t = iT/1000 - 10000*(sqlite3_int64)21086676;
+#if HAVE_GMTIME_R
+  pTm = gmtime_r(&t, &sNow);
+#else
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN));
+  pTm = gmtime(&t);
+  if( pTm ) memcpy(&sNow, pTm, sizeof(sNow));
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN));
+#endif
+  if( pTm ){
+    strftime(zBuf, 20, zFormat, &sNow);
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+  }
+}
+#endif
+
+#if !defined(SQLITE_OMIT_DATETIME_FUNCS) && defined(SQLITE_DEBUG)
+/*
+**   datedebug(...)
+**
+** This routine returns JSON that describes the internal DateTime object.
+** Used for debugging and testing only.  Subject to change.
+*/
+static void datedebugFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    char *zJson;
+    zJson = sqlite3_mprintf(
+      "{iJD:%lld,Y:%d,M:%d,D:%d,h:%d,m:%d,tz:%d,"
+      "s:%.3f,validJD:%d,validYMS:%d,validHMS:%d,"
+      "nFloor:%d,rawS:%d,isError:%d,useSubsec:%d,"
+      "isUtc:%d,isLocal:%d}",
+      x.iJD, x.Y, x.M, x.D, x.h, x.m, x.tz,
+      x.s, x.validJD, x.validYMD, x.validHMS,
+      x.nFloor, x.rawS, x.isError, x.useSubsec,
+      x.isUtc, x.isLocal);
+    sqlite3_result_text(context, zJson, -1, sqlite3_free);
+  }
+}
+#endif /* !SQLITE_OMIT_DATETIME_FUNCS && SQLITE_DEBUG */
+
+
+/*
+** This function registered all of the above C functions as SQL
+** functions.  This should be the only routine in this file with
+** external linkage.
+*/
+SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void){
+  static FuncDef aDateTimeFuncs[] = {
+#ifndef SQLITE_OMIT_DATETIME_FUNCS
+    PURE_DATE(julianday,        -1, 0, 0, juliandayFunc ),
+    PURE_DATE(unixepoch,        -1, 0, 0, unixepochFunc ),
+    PURE_DATE(date,             -1, 0, 0, dateFunc      ),
+    PURE_DATE(time,             -1, 0, 0, timeFunc      ),
+    PURE_DATE(datetime,         -1, 0, 0, datetimeFunc  ),
+    PURE_DATE(strftime,         -1, 0, 0, strftimeFunc  ),
+    PURE_DATE(timediff,          2, 0, 0, timediffFunc  ),
+#ifdef SQLITE_DEBUG
+    PURE_DATE(datedebug,        -1, 0, 0, datedebugFunc ),
+#endif
+    DFUNCTION(current_time,      0, 0, 0, ctimeFunc     ),
+    DFUNCTION(current_timestamp, 0, 0, 0, ctimestampFunc),
+    DFUNCTION(current_date,      0, 0, 0, cdateFunc     ),
+#else
+    STR_FUNCTION(current_time,      0, "%H:%M:%S",          0, currentTimeFunc),
+    STR_FUNCTION(current_date,      0, "%Y-%m-%d",          0, currentTimeFunc),
+    STR_FUNCTION(current_timestamp, 0, "%Y-%m-%d %H:%M:%S", 0, currentTimeFunc),
+#endif
+  };
+  sqlite3InsertBuiltinFuncs(aDateTimeFuncs, ArraySize(aDateTimeFuncs));
+}
+
+/************** End of date.c ************************************************/
+/************** Begin file os.c **********************************************/
+/*
+** 2005 November 29
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains OS interface code that is common to all
+** architectures.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** If we compile with the SQLITE_TEST macro set, then the following block
+** of code will give us the ability to simulate a disk I/O error.  This
+** is used for testing the I/O recovery logic.
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API int sqlite3_io_error_hit = 0;            /* Total number of I/O Errors */
+SQLITE_API int sqlite3_io_error_hardhit = 0;        /* Number of non-benign errors */
+SQLITE_API int sqlite3_io_error_pending = 0;        /* Count down to first I/O error */
+SQLITE_API int sqlite3_io_error_persist = 0;        /* True if I/O errors persist */
+SQLITE_API int sqlite3_io_error_benign = 0;         /* True if errors are benign */
+SQLITE_API int sqlite3_diskfull_pending = 0;
+SQLITE_API int sqlite3_diskfull = 0;
+#endif /* defined(SQLITE_TEST) */
+
+/*
+** When testing, also keep a count of the number of open files.
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API int sqlite3_open_file_count = 0;
+#endif /* defined(SQLITE_TEST) */
+
+/*
+** The default SQLite sqlite3_vfs implementations do not allocate
+** memory (actually, os_unix.c allocates a small amount of memory
+** from within OsOpen()), but some third-party implementations may.
+** So we test the effects of a malloc() failing and the sqlite3OsXXX()
+** function returning SQLITE_IOERR_NOMEM using the DO_OS_MALLOC_TEST macro.
+**
+** The following functions are instrumented for malloc() failure
+** testing:
+**
+**     sqlite3OsRead()
+**     sqlite3OsWrite()
+**     sqlite3OsSync()
+**     sqlite3OsFileSize()
+**     sqlite3OsLock()
+**     sqlite3OsCheckReservedLock()
+**     sqlite3OsFileControl()
+**     sqlite3OsShmMap()
+**     sqlite3OsOpen()
+**     sqlite3OsDelete()
+**     sqlite3OsAccess()
+**     sqlite3OsFullPathname()
+**
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API int sqlite3_memdebug_vfs_oom_test = 1;
+  #define DO_OS_MALLOC_TEST(x)                                       \
+  if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3JournalIsInMemory(x))) { \
+    void *pTstAlloc = sqlite3Malloc(10);                             \
+    if (!pTstAlloc) return SQLITE_IOERR_NOMEM_BKPT;                  \
+    sqlite3_free(pTstAlloc);                                         \
+  }
+#else
+  #define DO_OS_MALLOC_TEST(x)
+#endif
+
+/*
+** The following routines are convenience wrappers around methods
+** of the sqlite3_file object.  This is mostly just syntactic sugar. All
+** of this would be completely automatic if SQLite were coded using
+** C++ instead of plain old C.
+*/
+SQLITE_PRIVATE void sqlite3OsClose(sqlite3_file *pId){
+  if( pId->pMethods ){
+    pId->pMethods->xClose(pId);
+    pId->pMethods = 0;
+  }
+}
+SQLITE_PRIVATE int sqlite3OsRead(sqlite3_file *id, void *pBuf, int amt, i64 offset){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xRead(id, pBuf, amt, offset);
+}
+SQLITE_PRIVATE int sqlite3OsWrite(sqlite3_file *id, const void *pBuf, int amt, i64 offset){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xWrite(id, pBuf, amt, offset);
+}
+SQLITE_PRIVATE int sqlite3OsTruncate(sqlite3_file *id, i64 size){
+  return id->pMethods->xTruncate(id, size);
+}
+SQLITE_PRIVATE int sqlite3OsSync(sqlite3_file *id, int flags){
+  DO_OS_MALLOC_TEST(id);
+  return flags ? id->pMethods->xSync(id, flags) : SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3OsFileSize(sqlite3_file *id, i64 *pSize){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xFileSize(id, pSize);
+}
+SQLITE_PRIVATE int sqlite3OsLock(sqlite3_file *id, int lockType){
+  DO_OS_MALLOC_TEST(id);
+  assert( lockType>=SQLITE_LOCK_SHARED && lockType<=SQLITE_LOCK_EXCLUSIVE );
+  return id->pMethods->xLock(id, lockType);
+}
+SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file *id, int lockType){
+  assert( lockType==SQLITE_LOCK_NONE || lockType==SQLITE_LOCK_SHARED );
+  return id->pMethods->xUnlock(id, lockType);
+}
+SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xCheckReservedLock(id, pResOut);
+}
+
+/*
+** Use sqlite3OsFileControl() when we are doing something that might fail
+** and we need to know about the failures.  Use sqlite3OsFileControlHint()
+** when simply tossing information over the wall to the VFS and we do not
+** really care if the VFS receives and understands the information since it
+** is only a hint and can be safely ignored.  The sqlite3OsFileControlHint()
+** routine has no return value since the return value would be meaningless.
+*/
+SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){
+  if( id->pMethods==0 ) return SQLITE_NOTFOUND;
+#ifdef SQLITE_TEST
+  if( op!=SQLITE_FCNTL_COMMIT_PHASETWO
+   && op!=SQLITE_FCNTL_LOCK_TIMEOUT
+   && op!=SQLITE_FCNTL_CKPT_DONE
+   && op!=SQLITE_FCNTL_CKPT_START
+  ){
+    /* Faults are not injected into COMMIT_PHASETWO because, assuming SQLite
+    ** is using a regular VFS, it is called after the corresponding
+    ** transaction has been committed. Injecting a fault at this point
+    ** confuses the test scripts - the COMMIT command returns SQLITE_NOMEM
+    ** but the transaction is committed anyway.
+    **
+    ** The core must call OsFileControl() though, not OsFileControlHint(),
+    ** as if a custom VFS (e.g. zipvfs) returns an error here, it probably
+    ** means the commit really has failed and an error should be returned
+    ** to the user.
+    **
+    ** The CKPT_DONE and CKPT_START file-controls are write-only signals
+    ** to the cksumvfs.  Their return code is meaningless and is ignored
+    ** by the SQLite core, so there is no point in simulating OOMs for them.
+    */
+    DO_OS_MALLOC_TEST(id);
+  }
+#endif
+  return id->pMethods->xFileControl(id, op, pArg);
+}
+SQLITE_PRIVATE void sqlite3OsFileControlHint(sqlite3_file *id, int op, void *pArg){
+  if( id->pMethods ) (void)id->pMethods->xFileControl(id, op, pArg);
+}
+
+SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id){
+  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
+  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
+}
+SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
+  if( NEVER(id->pMethods==0) ) return 0;
+  return id->pMethods->xDeviceCharacteristics(id);
+}
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE int sqlite3OsShmLock(sqlite3_file *id, int offset, int n, int flags){
+  return id->pMethods->xShmLock(id, offset, n, flags);
+}
+SQLITE_PRIVATE void sqlite3OsShmBarrier(sqlite3_file *id){
+  id->pMethods->xShmBarrier(id);
+}
+SQLITE_PRIVATE int sqlite3OsShmUnmap(sqlite3_file *id, int deleteFlag){
+  return id->pMethods->xShmUnmap(id, deleteFlag);
+}
+SQLITE_PRIVATE int sqlite3OsShmMap(
+  sqlite3_file *id,               /* Database file handle */
+  int iPage,
+  int pgsz,
+  int bExtend,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Pointer to mapping */
+){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp);
+}
+#endif /* SQLITE_OMIT_WAL */
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/* The real implementation of xFetch and xUnfetch */
+SQLITE_PRIVATE int sqlite3OsFetch(sqlite3_file *id, i64 iOff, int iAmt, void **pp){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xFetch(id, iOff, iAmt, pp);
+}
+SQLITE_PRIVATE int sqlite3OsUnfetch(sqlite3_file *id, i64 iOff, void *p){
+  return id->pMethods->xUnfetch(id, iOff, p);
+}
+#else
+/* No-op stubs to use when memory-mapped I/O is disabled */
+SQLITE_PRIVATE int sqlite3OsFetch(sqlite3_file *id, i64 iOff, int iAmt, void **pp){
+  *pp = 0;
+  return SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3OsUnfetch(sqlite3_file *id, i64 iOff, void *p){
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** The next group of routines are convenience wrappers around the
+** VFS methods.
+*/
+SQLITE_PRIVATE int sqlite3OsOpen(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  sqlite3_file *pFile,
+  int flags,
+  int *pFlagsOut
+){
+  int rc;
+  DO_OS_MALLOC_TEST(0);
+  /* 0x87f7f is a mask of SQLITE_OPEN_ flags that are valid to be passed
+  ** down into the VFS layer.  Some SQLITE_OPEN_ flags (for example,
+  ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
+  ** reaching the VFS. */
+  assert( zPath || (flags & SQLITE_OPEN_EXCLUSIVE) );
+  rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x1087f7f, pFlagsOut);
+  assert( rc==SQLITE_OK || pFile->pMethods==0 );
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  DO_OS_MALLOC_TEST(0);
+  assert( dirSync==0 || dirSync==1 );
+  return pVfs->xDelete!=0 ? pVfs->xDelete(pVfs, zPath, dirSync) : SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3OsAccess(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int flags,
+  int *pResOut
+){
+  DO_OS_MALLOC_TEST(0);
+  return pVfs->xAccess(pVfs, zPath, flags, pResOut);
+}
+SQLITE_PRIVATE int sqlite3OsFullPathname(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int nPathOut,
+  char *zPathOut
+){
+  DO_OS_MALLOC_TEST(0);
+  zPathOut[0] = 0;
+  return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
+}
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  assert( zPath!=0 );
+  assert( strlen(zPath)<=SQLITE_MAX_PATHLEN );  /* tag-20210611-1 */
+  return pVfs->xDlOpen(pVfs, zPath);
+}
+SQLITE_PRIVATE void sqlite3OsDlError(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  pVfs->xDlError(pVfs, nByte, zBufOut);
+}
+SQLITE_PRIVATE void (*sqlite3OsDlSym(sqlite3_vfs *pVfs, void *pHdle, const char *zSym))(void){
+  return pVfs->xDlSym(pVfs, pHdle, zSym);
+}
+SQLITE_PRIVATE void sqlite3OsDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  pVfs->xDlClose(pVfs, pHandle);
+}
+#endif /* SQLITE_OMIT_LOAD_EXTENSION */
+SQLITE_PRIVATE int sqlite3OsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  if( sqlite3Config.iPrngSeed ){
+    memset(zBufOut, 0, nByte);
+    if( ALWAYS(nByte>(signed)sizeof(unsigned)) ) nByte = sizeof(unsigned int);
+    memcpy(zBufOut, &sqlite3Config.iPrngSeed, nByte);
+    return SQLITE_OK;
+  }else{
+    return pVfs->xRandomness(pVfs, nByte, zBufOut);
+  }
+
+}
+SQLITE_PRIVATE int sqlite3OsSleep(sqlite3_vfs *pVfs, int nMicro){
+  return pVfs->xSleep(pVfs, nMicro);
+}
+SQLITE_PRIVATE int sqlite3OsGetLastError(sqlite3_vfs *pVfs){
+  return pVfs->xGetLastError ? pVfs->xGetLastError(pVfs, 0, 0) : 0;
+}
+SQLITE_PRIVATE int sqlite3OsCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
+  int rc;
+  /* IMPLEMENTATION-OF: R-49045-42493 SQLite will use the xCurrentTimeInt64()
+  ** method to get the current date and time if that method is available
+  ** (if iVersion is 2 or greater and the function pointer is not NULL) and
+  ** will fall back to xCurrentTime() if xCurrentTimeInt64() is
+  ** unavailable.
+  */
+  if( pVfs->iVersion>=2 && pVfs->xCurrentTimeInt64 ){
+    rc = pVfs->xCurrentTimeInt64(pVfs, pTimeOut);
+  }else{
+    double r;
+    rc = pVfs->xCurrentTime(pVfs, &r);
+    *pTimeOut = (sqlite3_int64)(r*86400000.0);
+  }
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3OsOpenMalloc(
+  sqlite3_vfs *pVfs,
+  const char *zFile,
+  sqlite3_file **ppFile,
+  int flags,
+  int *pOutFlags
+){
+  int rc;
+  sqlite3_file *pFile;
+  pFile = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile);
+  if( pFile ){
+    rc = sqlite3OsOpen(pVfs, zFile, pFile, flags, pOutFlags);
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(pFile);
+      *ppFile = 0;
+    }else{
+      *ppFile = pFile;
+    }
+  }else{
+    *ppFile = 0;
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  assert( *ppFile!=0 || rc!=SQLITE_OK );
+  return rc;
+}
+SQLITE_PRIVATE void sqlite3OsCloseFree(sqlite3_file *pFile){
+  assert( pFile );
+  sqlite3OsClose(pFile);
+  sqlite3_free(pFile);
+}
+
+/*
+** This function is a wrapper around the OS specific implementation of
+** sqlite3_os_init(). The purpose of the wrapper is to provide the
+** ability to simulate a malloc failure, so that the handling of an
+** error in sqlite3_os_init() by the upper layers can be tested.
+*/
+SQLITE_PRIVATE int sqlite3OsInit(void){
+  void *p = sqlite3_malloc(10);
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  sqlite3_free(p);
+  return sqlite3_os_init();
+}
+
+/*
+** The list of all registered VFS implementations.
+*/
+static sqlite3_vfs * SQLITE_WSD vfsList = 0;
+#define vfsList GLOBAL(sqlite3_vfs *, vfsList)
+
+/*
+** Locate a VFS by name.  If no name is given, simply return the
+** first VFS on the list.
+*/
+SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfs){
+  sqlite3_vfs *pVfs = 0;
+#if SQLITE_THREADSAFE
+  sqlite3_mutex *mutex;
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return 0;
+#endif
+#if SQLITE_THREADSAFE
+  mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+  sqlite3_mutex_enter(mutex);
+  for(pVfs = vfsList; pVfs; pVfs=pVfs->pNext){
+    if( zVfs==0 ) break;
+    if( strcmp(zVfs, pVfs->zName)==0 ) break;
+  }
+  sqlite3_mutex_leave(mutex);
+  return pVfs;
+}
+
+/*
+** Unlink a VFS from the linked list
+*/
+static void vfsUnlink(sqlite3_vfs *pVfs){
+  assert( sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN)) );
+  if( pVfs==0 ){
+    /* No-op */
+  }else if( vfsList==pVfs ){
+    vfsList = pVfs->pNext;
+  }else if( vfsList ){
+    sqlite3_vfs *p = vfsList;
+    while( p->pNext && p->pNext!=pVfs ){
+      p = p->pNext;
+    }
+    if( p->pNext==pVfs ){
+      p->pNext = pVfs->pNext;
+    }
+  }
+}
+
+/*
+** Register a VFS with the system.  It is harmless to register the same
+** VFS multiple times.  The new VFS becomes the default if makeDflt is
+** true.
+*/
+SQLITE_API int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){
+  MUTEX_LOGIC(sqlite3_mutex *mutex;)
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pVfs==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+
+  MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  sqlite3_mutex_enter(mutex);
+  vfsUnlink(pVfs);
+  if( makeDflt || vfsList==0 ){
+    pVfs->pNext = vfsList;
+    vfsList = pVfs;
+  }else{
+    pVfs->pNext = vfsList->pNext;
+    vfsList->pNext = pVfs;
+  }
+  assert(vfsList);
+  sqlite3_mutex_leave(mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Unregister a VFS so that it is no longer accessible.
+*/
+SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs *pVfs){
+  MUTEX_LOGIC(sqlite3_mutex *mutex;)
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+  MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  sqlite3_mutex_enter(mutex);
+  vfsUnlink(pVfs);
+  sqlite3_mutex_leave(mutex);
+  return SQLITE_OK;
+}
+
+/************** End of os.c **************************************************/
+/************** Begin file fault.c *******************************************/
+/*
+** 2008 Jan 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code to support the concept of "benign"
+** malloc failures (when the xMalloc() or xRealloc() method of the
+** sqlite3_mem_methods structure fails to allocate a block of memory
+** and returns 0).
+**
+** Most malloc failures are non-benign. After they occur, SQLite
+** abandons the current operation and returns an error code (usually
+** SQLITE_NOMEM) to the user. However, sometimes a fault is not necessarily
+** fatal. For example, if a malloc fails while resizing a hash table, this
+** is completely recoverable simply by not carrying out the resize. The
+** hash table will continue to function normally.  So a malloc failure
+** during a hash table resize is a benign fault.
+*/
+
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_UNTESTABLE
+
+/*
+** Global variables.
+*/
+typedef struct BenignMallocHooks BenignMallocHooks;
+static SQLITE_WSD struct BenignMallocHooks {
+  void (*xBenignBegin)(void);
+  void (*xBenignEnd)(void);
+} sqlite3Hooks = { 0, 0 };
+
+/* The "wsdHooks" macro will resolve to the appropriate BenignMallocHooks
+** structure.  If writable static data is unsupported on the target,
+** we have to locate the state vector at run-time.  In the more common
+** case where writable static data is supported, wsdHooks can refer directly
+** to the "sqlite3Hooks" state vector declared above.
+*/
+#ifdef SQLITE_OMIT_WSD
+# define wsdHooksInit \
+  BenignMallocHooks *x = &GLOBAL(BenignMallocHooks,sqlite3Hooks)
+# define wsdHooks x[0]
+#else
+# define wsdHooksInit
+# define wsdHooks sqlite3Hooks
+#endif
+
+
+/*
+** Register hooks to call when sqlite3BeginBenignMalloc() and
+** sqlite3EndBenignMalloc() are called, respectively.
+*/
+SQLITE_PRIVATE void sqlite3BenignMallocHooks(
+  void (*xBenignBegin)(void),
+  void (*xBenignEnd)(void)
+){
+  wsdHooksInit;
+  wsdHooks.xBenignBegin = xBenignBegin;
+  wsdHooks.xBenignEnd = xBenignEnd;
+}
+
+/*
+** This (sqlite3EndBenignMalloc()) is called by SQLite code to indicate that
+** subsequent malloc failures are benign. A call to sqlite3EndBenignMalloc()
+** indicates that subsequent malloc failures are non-benign.
+*/
+SQLITE_PRIVATE void sqlite3BeginBenignMalloc(void){
+  wsdHooksInit;
+  if( wsdHooks.xBenignBegin ){
+    wsdHooks.xBenignBegin();
+  }
+}
+SQLITE_PRIVATE void sqlite3EndBenignMalloc(void){
+  wsdHooksInit;
+  if( wsdHooks.xBenignEnd ){
+    wsdHooks.xBenignEnd();
+  }
+}
+
+#endif   /* #ifndef SQLITE_UNTESTABLE */
+
+/************** End of fault.c ***********************************************/
+/************** Begin file mem0.c ********************************************/
+/*
+** 2008 October 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains a no-op memory allocation drivers for use when
+** SQLITE_ZERO_MALLOC is defined.  The allocation drivers implemented
+** here always fail.  SQLite will not operate with these drivers.  These
+** are merely placeholders.  Real drivers must be substituted using
+** sqlite3_config() before SQLite will operate.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is the default.  It is
+** used when no other memory allocator is specified using compile-time
+** macros.
+*/
+#ifdef SQLITE_ZERO_MALLOC
+
+/*
+** No-op versions of all memory allocation routines
+*/
+static void *sqlite3MemMalloc(int nByte){ return 0; }
+static void sqlite3MemFree(void *pPrior){ return; }
+static void *sqlite3MemRealloc(void *pPrior, int nByte){ return 0; }
+static int sqlite3MemSize(void *pPrior){ return 0; }
+static int sqlite3MemRoundup(int n){ return n; }
+static int sqlite3MemInit(void *NotUsed){ return SQLITE_OK; }
+static void sqlite3MemShutdown(void *NotUsed){ return; }
+
+/*
+** This routine is the only routine in this file with external linkage.
+**
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file.
+*/
+SQLITE_PRIVATE void sqlite3MemSetDefault(void){
+  static const sqlite3_mem_methods defaultMethods = {
+     sqlite3MemMalloc,
+     sqlite3MemFree,
+     sqlite3MemRealloc,
+     sqlite3MemSize,
+     sqlite3MemRoundup,
+     sqlite3MemInit,
+     sqlite3MemShutdown,
+     0
+  };
+  sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods);
+}
+
+#endif /* SQLITE_ZERO_MALLOC */
+
+/************** End of mem0.c ************************************************/
+/************** Begin file mem1.c ********************************************/
+/*
+** 2007 August 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains low-level memory allocation drivers for when
+** SQLite will use the standard C-library malloc/realloc/free interface
+** to obtain the memory it needs.
+**
+** This file contains implementations of the low-level memory allocation
+** routines specified in the sqlite3_mem_methods object.  The content of
+** this file is only used if SQLITE_SYSTEM_MALLOC is defined.  The
+** SQLITE_SYSTEM_MALLOC macro is defined automatically if neither the
+** SQLITE_MEMDEBUG nor the SQLITE_WIN32_MALLOC macros are defined.  The
+** default configuration is to use memory allocation routines in this
+** file.
+**
+** C-preprocessor macro summary:
+**
+**    HAVE_MALLOC_USABLE_SIZE     The configure script sets this symbol if
+**                                the malloc_usable_size() interface exists
+**                                on the target platform.  Or, this symbol
+**                                can be set manually, if desired.
+**                                If an equivalent interface exists by
+**                                a different name, using a separate -D
+**                                option to rename it.
+**
+**    SQLITE_WITHOUT_ZONEMALLOC   Some older macs lack support for the zone
+**                                memory allocator.  Set this symbol to enable
+**                                building on older macs.
+**
+**    SQLITE_WITHOUT_MSIZE        Set this symbol to disable the use of
+**                                _msize() on windows systems.  This might
+**                                be necessary when compiling for Delphi,
+**                                for example.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is the default.  It is
+** used when no other memory allocator is specified using compile-time
+** macros.
+*/
+#ifdef SQLITE_SYSTEM_MALLOC
+#if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC)
+
+/*
+** Use the zone allocator available on apple products unless the
+** SQLITE_WITHOUT_ZONEMALLOC symbol is defined.
+*/
+#include <sys/sysctl.h>
+#include <malloc/malloc.h>
+#ifdef SQLITE_MIGHT_BE_SINGLE_CORE
+#include <libkern/OSAtomic.h>
+#endif /* SQLITE_MIGHT_BE_SINGLE_CORE */
+static malloc_zone_t* _sqliteZone_;
+#define SQLITE_MALLOC(x) malloc_zone_malloc(_sqliteZone_, (x))
+#define SQLITE_FREE(x) malloc_zone_free(_sqliteZone_, (x));
+#define SQLITE_REALLOC(x,y) malloc_zone_realloc(_sqliteZone_, (x), (y))
+#define SQLITE_MALLOCSIZE(x) \
+        (_sqliteZone_ ? _sqliteZone_->size(_sqliteZone_,x) : malloc_size(x))
+
+#else /* if not __APPLE__ */
+
+/*
+** Use standard C library malloc and free on non-Apple systems.
+** Also used by Apple systems if SQLITE_WITHOUT_ZONEMALLOC is defined.
+*/
+#define SQLITE_MALLOC(x)             malloc(x)
+#define SQLITE_FREE(x)               free(x)
+#define SQLITE_REALLOC(x,y)          realloc((x),(y))
+
+/*
+** The malloc.h header file is needed for malloc_usable_size() function
+** on some systems (e.g. Linux).
+*/
+#if HAVE_MALLOC_H && HAVE_MALLOC_USABLE_SIZE
+#  define SQLITE_USE_MALLOC_H 1
+#  define SQLITE_USE_MALLOC_USABLE_SIZE 1
+/*
+** The MSVCRT has malloc_usable_size(), but it is called _msize().  The
+** use of _msize() is automatic, but can be disabled by compiling with
+** -DSQLITE_WITHOUT_MSIZE.  Using the _msize() function also requires
+** the malloc.h header file.
+*/
+#elif defined(_MSC_VER) && !defined(SQLITE_WITHOUT_MSIZE)
+#  define SQLITE_USE_MALLOC_H
+#  define SQLITE_USE_MSIZE
+#endif
+
+/*
+** Include the malloc.h header file, if necessary.  Also set define macro
+** SQLITE_MALLOCSIZE to the appropriate function name, which is _msize()
+** for MSVC and malloc_usable_size() for most other systems (e.g. Linux).
+** The memory size function can always be overridden manually by defining
+** the macro SQLITE_MALLOCSIZE to the desired function name.
+*/
+#if defined(SQLITE_USE_MALLOC_H)
+#  include <malloc.h>
+#  if defined(SQLITE_USE_MALLOC_USABLE_SIZE)
+#    if !defined(SQLITE_MALLOCSIZE)
+#      define SQLITE_MALLOCSIZE(x)   malloc_usable_size(x)
+#    endif
+#  elif defined(SQLITE_USE_MSIZE)
+#    if !defined(SQLITE_MALLOCSIZE)
+#      define SQLITE_MALLOCSIZE      _msize
+#    endif
+#  endif
+#endif /* defined(SQLITE_USE_MALLOC_H) */
+
+#endif /* __APPLE__ or not __APPLE__ */
+
+/*
+** Like malloc(), but remember the size of the allocation
+** so that we can find it later using sqlite3MemSize().
+**
+** For this low-level routine, we are guaranteed that nByte>0 because
+** cases of nByte<=0 will be intercepted and dealt with by higher level
+** routines.
+*/
+static void *sqlite3MemMalloc(int nByte){
+#ifdef SQLITE_MALLOCSIZE
+  void *p;
+  testcase( ROUND8(nByte)==nByte );
+  p = SQLITE_MALLOC( nByte );
+  if( p==0 ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
+  }
+  return p;
+#else
+  sqlite3_int64 *p;
+  assert( nByte>0 );
+  testcase( ROUND8(nByte)!=nByte );
+  p = SQLITE_MALLOC( nByte+8 );
+  if( p ){
+    p[0] = nByte;
+    p++;
+  }else{
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
+  }
+  return (void *)p;
+#endif
+}
+
+/*
+** Like free() but works for allocations obtained from sqlite3MemMalloc()
+** or sqlite3MemRealloc().
+**
+** For this low-level routine, we already know that pPrior!=0 since
+** cases where pPrior==0 will have been intercepted and dealt with
+** by higher-level routines.
+*/
+static void sqlite3MemFree(void *pPrior){
+#ifdef SQLITE_MALLOCSIZE
+  SQLITE_FREE(pPrior);
+#else
+  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
+  assert( pPrior!=0 );
+  p--;
+  SQLITE_FREE(p);
+#endif
+}
+
+/*
+** Report the allocated size of a prior return from xMalloc()
+** or xRealloc().
+*/
+static int sqlite3MemSize(void *pPrior){
+#ifdef SQLITE_MALLOCSIZE
+  assert( pPrior!=0 );
+  return (int)SQLITE_MALLOCSIZE(pPrior);
+#else
+  sqlite3_int64 *p;
+  assert( pPrior!=0 );
+  p = (sqlite3_int64*)pPrior;
+  p--;
+  return (int)p[0];
+#endif
+}
+
+/*
+** Like realloc().  Resize an allocation previously obtained from
+** sqlite3MemMalloc().
+**
+** For this low-level interface, we know that pPrior!=0.  Cases where
+** pPrior==0 while have been intercepted by higher-level routine and
+** redirected to xMalloc.  Similarly, we know that nByte>0 because
+** cases where nByte<=0 will have been intercepted by higher-level
+** routines and redirected to xFree.
+*/
+static void *sqlite3MemRealloc(void *pPrior, int nByte){
+#ifdef SQLITE_MALLOCSIZE
+  void *p = SQLITE_REALLOC(pPrior, nByte);
+  if( p==0 ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM,
+      "failed memory resize %u to %u bytes",
+      SQLITE_MALLOCSIZE(pPrior), nByte);
+  }
+  return p;
+#else
+  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
+  assert( pPrior!=0 && nByte>0 );
+  assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */
+  p--;
+  p = SQLITE_REALLOC(p, nByte+8 );
+  if( p ){
+    p[0] = nByte;
+    p++;
+  }else{
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM,
+      "failed memory resize %u to %u bytes",
+      sqlite3MemSize(pPrior), nByte);
+  }
+  return (void*)p;
+#endif
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int sqlite3MemRoundup(int n){
+  return ROUND8(n);
+}
+
+/*
+** Initialize this module.
+*/
+static int sqlite3MemInit(void *NotUsed){
+#if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC)
+  int cpuCount;
+  size_t len;
+  if( _sqliteZone_ ){
+    return SQLITE_OK;
+  }
+  len = sizeof(cpuCount);
+  /* One usually wants to use hw.activecpu for MT decisions, but not here */
+  sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0);
+  if( cpuCount>1 ){
+    /* defer MT decisions to system malloc */
+    _sqliteZone_ = malloc_default_zone();
+  }else{
+    /* only 1 core, use our own zone to contention over global locks,
+    ** e.g. we have our own dedicated locks */
+    _sqliteZone_ = malloc_create_zone(4096, 0);
+    malloc_set_zone_name(_sqliteZone_, "Sqlite_Heap");
+  }
+#endif /*  defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC) */
+  UNUSED_PARAMETER(NotUsed);
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize this module.
+*/
+static void sqlite3MemShutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  return;
+}
+
+/*
+** This routine is the only routine in this file with external linkage.
+**
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file.
+*/
+SQLITE_PRIVATE void sqlite3MemSetDefault(void){
+  static const sqlite3_mem_methods defaultMethods = {
+     sqlite3MemMalloc,
+     sqlite3MemFree,
+     sqlite3MemRealloc,
+     sqlite3MemSize,
+     sqlite3MemRoundup,
+     sqlite3MemInit,
+     sqlite3MemShutdown,
+     0
+  };
+  sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods);
+}
+
+#endif /* SQLITE_SYSTEM_MALLOC */
+
+/************** End of mem1.c ************************************************/
+/************** Begin file mem2.c ********************************************/
+/*
+** 2007 August 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains low-level memory allocation drivers for when
+** SQLite will use the standard C-library malloc/realloc/free interface
+** to obtain the memory it needs while adding lots of additional debugging
+** information to each allocation in order to help detect and fix memory
+** leaks and memory usage errors.
+**
+** This file contains implementations of the low-level memory allocation
+** routines specified in the sqlite3_mem_methods object.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is used only if the
+** SQLITE_MEMDEBUG macro is defined
+*/
+#ifdef SQLITE_MEMDEBUG
+
+/*
+** The backtrace functionality is only available with GLIBC
+*/
+#ifdef __GLIBC__
+  extern int backtrace(void**,int);
+  extern void backtrace_symbols_fd(void*const*,int,int);
+#else
+# define backtrace(A,B) 1
+# define backtrace_symbols_fd(A,B,C)
+#endif
+/* #include <stdio.h> */
+
+/*
+** Each memory allocation looks like this:
+**
+**  ------------------------------------------------------------------------
+**  | Title |  backtrace pointers |  MemBlockHdr |  allocation |  EndGuard |
+**  ------------------------------------------------------------------------
+**
+** The application code sees only a pointer to the allocation.  We have
+** to back up from the allocation pointer to find the MemBlockHdr.  The
+** MemBlockHdr tells us the size of the allocation and the number of
+** backtrace pointers.  There is also a guard word at the end of the
+** MemBlockHdr.
+*/
+struct MemBlockHdr {
+  i64 iSize;                          /* Size of this allocation */
+  struct MemBlockHdr *pNext, *pPrev;  /* Linked list of all unfreed memory */
+  char nBacktrace;                    /* Number of backtraces on this alloc */
+  char nBacktraceSlots;               /* Available backtrace slots */
+  u8 nTitle;                          /* Bytes of title; includes '\0' */
+  u8 eType;                           /* Allocation type code */
+  int iForeGuard;                     /* Guard word for sanity */
+};
+
+/*
+** Guard words
+*/
+#define FOREGUARD 0x80F5E153
+#define REARGUARD 0xE4676B53
+
+/*
+** Number of malloc size increments to track.
+*/
+#define NCSIZE  1000
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static struct {
+
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+
+  /*
+  ** Head and tail of a linked list of all outstanding allocations
+  */
+  struct MemBlockHdr *pFirst;
+  struct MemBlockHdr *pLast;
+
+  /*
+  ** The number of levels of backtrace to save in new allocations.
+  */
+  int nBacktrace;
+  void (*xBacktrace)(int, int, void **);
+
+  /*
+  ** Title text to insert in front of each block
+  */
+  int nTitle;        /* Bytes of zTitle to save.  Includes '\0' and padding */
+  char zTitle[100];  /* The title text */
+
+  /*
+  ** sqlite3MallocDisallow() increments the following counter.
+  ** sqlite3MallocAllow() decrements it.
+  */
+  int disallow; /* Do not allow memory allocation */
+
+  /*
+  ** Gather statistics on the sizes of memory allocations.
+  ** nAlloc[i] is the number of allocation attempts of i*8
+  ** bytes.  i==NCSIZE is the number of allocation attempts for
+  ** sizes more than NCSIZE*8 bytes.
+  */
+  int nAlloc[NCSIZE];      /* Total number of allocations */
+  int nCurrent[NCSIZE];    /* Current number of allocations */
+  int mxCurrent[NCSIZE];   /* Highwater mark for nCurrent */
+
+} mem;
+
+
+/*
+** Adjust memory usage statistics
+*/
+static void adjustStats(int iSize, int increment){
+  int i = ROUND8(iSize)/8;
+  if( i>NCSIZE-1 ){
+    i = NCSIZE - 1;
+  }
+  if( increment>0 ){
+    mem.nAlloc[i]++;
+    mem.nCurrent[i]++;
+    if( mem.nCurrent[i]>mem.mxCurrent[i] ){
+      mem.mxCurrent[i] = mem.nCurrent[i];
+    }
+  }else{
+    mem.nCurrent[i]--;
+    assert( mem.nCurrent[i]>=0 );
+  }
+}
+
+/*
+** Given an allocation, find the MemBlockHdr for that allocation.
+**
+** This routine checks the guards at either end of the allocation and
+** if they are incorrect it asserts.
+*/
+static struct MemBlockHdr *sqlite3MemsysGetHeader(const void *pAllocation){
+  struct MemBlockHdr *p;
+  int *pInt;
+  u8 *pU8;
+  int nReserve;
+
+  p = (struct MemBlockHdr*)pAllocation;
+  p--;
+  assert( p->iForeGuard==(int)FOREGUARD );
+  nReserve = ROUND8(p->iSize);
+  pInt = (int*)pAllocation;
+  pU8 = (u8*)pAllocation;
+  assert( pInt[nReserve/sizeof(int)]==(int)REARGUARD );
+  /* This checks any of the "extra" bytes allocated due
+  ** to rounding up to an 8 byte boundary to ensure
+  ** they haven't been overwritten.
+  */
+  while( nReserve-- > p->iSize ) assert( pU8[nReserve]==0x65 );
+  return p;
+}
+
+/*
+** Return the number of bytes currently allocated at address p.
+*/
+static int sqlite3MemSize(void *p){
+  struct MemBlockHdr *pHdr;
+  if( !p ){
+    return 0;
+  }
+  pHdr = sqlite3MemsysGetHeader(p);
+  return (int)pHdr->iSize;
+}
+
+/*
+** Initialize the memory allocation subsystem.
+*/
+static int sqlite3MemInit(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  assert( (sizeof(struct MemBlockHdr)&7) == 0 );
+  if( !sqlite3GlobalConfig.bMemstat ){
+    /* If memory status is enabled, then the malloc.c wrapper will already
+    ** hold the STATIC_MEM mutex when the routines here are invoked. */
+    mem.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize the memory allocation subsystem.
+*/
+static void sqlite3MemShutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  mem.mutex = 0;
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int sqlite3MemRoundup(int n){
+  return ROUND8(n);
+}
+
+/*
+** Fill a buffer with pseudo-random bytes.  This is used to preset
+** the content of a new memory allocation to unpredictable values and
+** to clear the content of a freed allocation to unpredictable values.
+*/
+static void randomFill(char *pBuf, int nByte){
+  unsigned int x, y, r;
+  x = SQLITE_PTR_TO_INT(pBuf);
+  y = nByte | 1;
+  while( nByte >= 4 ){
+    x = (x>>1) ^ (-(int)(x&1) & 0xd0000001);
+    y = y*1103515245 + 12345;
+    r = x ^ y;
+    *(int*)pBuf = r;
+    pBuf += 4;
+    nByte -= 4;
+  }
+  while( nByte-- > 0 ){
+    x = (x>>1) ^ (-(int)(x&1) & 0xd0000001);
+    y = y*1103515245 + 12345;
+    r = x ^ y;
+    *(pBuf++) = r & 0xff;
+  }
+}
+
+/*
+** Allocate nByte bytes of memory.
+*/
+static void *sqlite3MemMalloc(int nByte){
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  char *z;
+  int *pInt;
+  void *p = 0;
+  int totalSize;
+  int nReserve;
+  sqlite3_mutex_enter(mem.mutex);
+  assert( mem.disallow==0 );
+  nReserve = ROUND8(nByte);
+  totalSize = nReserve + sizeof(*pHdr) + sizeof(int) +
+               mem.nBacktrace*sizeof(void*) + mem.nTitle;
+  p = malloc(totalSize);
+  if( p ){
+    z = p;
+    pBt = (void**)&z[mem.nTitle];
+    pHdr = (struct MemBlockHdr*)&pBt[mem.nBacktrace];
+    pHdr->pNext = 0;
+    pHdr->pPrev = mem.pLast;
+    if( mem.pLast ){
+      mem.pLast->pNext = pHdr;
+    }else{
+      mem.pFirst = pHdr;
+    }
+    mem.pLast = pHdr;
+    pHdr->iForeGuard = FOREGUARD;
+    pHdr->eType = MEMTYPE_HEAP;
+    pHdr->nBacktraceSlots = mem.nBacktrace;
+    pHdr->nTitle = mem.nTitle;
+    if( mem.nBacktrace ){
+      void *aAddr[40];
+      pHdr->nBacktrace = backtrace(aAddr, mem.nBacktrace+1)-1;
+      memcpy(pBt, &aAddr[1], pHdr->nBacktrace*sizeof(void*));
+      assert(pBt[0]);
+      if( mem.xBacktrace ){
+        mem.xBacktrace(nByte, pHdr->nBacktrace-1, &aAddr[1]);
+      }
+    }else{
+      pHdr->nBacktrace = 0;
+    }
+    if( mem.nTitle ){
+      memcpy(z, mem.zTitle, mem.nTitle);
+    }
+    pHdr->iSize = nByte;
+    adjustStats(nByte, +1);
+    pInt = (int*)&pHdr[1];
+    pInt[nReserve/sizeof(int)] = REARGUARD;
+    randomFill((char*)pInt, nByte);
+    memset(((char*)pInt)+nByte, 0x65, nReserve-nByte);
+    p = (void*)pInt;
+  }
+  sqlite3_mutex_leave(mem.mutex);
+  return p;
+}
+
+/*
+** Free memory.
+*/
+static void sqlite3MemFree(void *pPrior){
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  char *z;
+  assert( sqlite3GlobalConfig.bMemstat || sqlite3GlobalConfig.bCoreMutex==0
+       || mem.mutex!=0 );
+  pHdr = sqlite3MemsysGetHeader(pPrior);
+  pBt = (void**)pHdr;
+  pBt -= pHdr->nBacktraceSlots;
+  sqlite3_mutex_enter(mem.mutex);
+  if( pHdr->pPrev ){
+    assert( pHdr->pPrev->pNext==pHdr );
+    pHdr->pPrev->pNext = pHdr->pNext;
+  }else{
+    assert( mem.pFirst==pHdr );
+    mem.pFirst = pHdr->pNext;
+  }
+  if( pHdr->pNext ){
+    assert( pHdr->pNext->pPrev==pHdr );
+    pHdr->pNext->pPrev = pHdr->pPrev;
+  }else{
+    assert( mem.pLast==pHdr );
+    mem.pLast = pHdr->pPrev;
+  }
+  z = (char*)pBt;
+  z -= pHdr->nTitle;
+  adjustStats((int)pHdr->iSize, -1);
+  randomFill(z, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
+                (int)pHdr->iSize + sizeof(int) + pHdr->nTitle);
+  free(z);
+  sqlite3_mutex_leave(mem.mutex);
+}
+
+/*
+** Change the size of an existing memory allocation.
+**
+** For this debugging implementation, we *always* make a copy of the
+** allocation into a new place in memory.  In this way, if the
+** higher level code is using pointer to the old allocation, it is
+** much more likely to break and we are much more liking to find
+** the error.
+*/
+static void *sqlite3MemRealloc(void *pPrior, int nByte){
+  struct MemBlockHdr *pOldHdr;
+  void *pNew;
+  assert( mem.disallow==0 );
+  assert( (nByte & 7)==0 );     /* EV: R-46199-30249 */
+  pOldHdr = sqlite3MemsysGetHeader(pPrior);
+  pNew = sqlite3MemMalloc(nByte);
+  if( pNew ){
+    memcpy(pNew, pPrior, (int)(nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize));
+    if( nByte>pOldHdr->iSize ){
+      randomFill(&((char*)pNew)[pOldHdr->iSize], nByte - (int)pOldHdr->iSize);
+    }
+    sqlite3MemFree(pPrior);
+  }
+  return pNew;
+}
+
+/*
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file.
+*/
+SQLITE_PRIVATE void sqlite3MemSetDefault(void){
+  static const sqlite3_mem_methods defaultMethods = {
+     sqlite3MemMalloc,
+     sqlite3MemFree,
+     sqlite3MemRealloc,
+     sqlite3MemSize,
+     sqlite3MemRoundup,
+     sqlite3MemInit,
+     sqlite3MemShutdown,
+     0
+  };
+  sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods);
+}
+
+/*
+** Set the "type" of an allocation.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugSetType(void *p, u8 eType){
+  if( p && sqlite3GlobalConfig.m.xFree==sqlite3MemFree ){
+    struct MemBlockHdr *pHdr;
+    pHdr = sqlite3MemsysGetHeader(p);
+    assert( pHdr->iForeGuard==FOREGUARD );
+    pHdr->eType = eType;
+  }
+}
+
+/*
+** Return TRUE if the mask of type in eType matches the type of the
+** allocation p.  Also return true if p==NULL.
+**
+** This routine is designed for use within an assert() statement, to
+** verify the type of an allocation.  For example:
+**
+**     assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+*/
+SQLITE_PRIVATE int sqlite3MemdebugHasType(const void *p, u8 eType){
+  int rc = 1;
+  if( p && sqlite3GlobalConfig.m.xFree==sqlite3MemFree ){
+    struct MemBlockHdr *pHdr;
+    pHdr = sqlite3MemsysGetHeader(p);
+    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */
+    if( (pHdr->eType&eType)==0 ){
+      rc = 0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Return TRUE if the mask of type in eType matches no bits of the type of the
+** allocation p.  Also return true if p==NULL.
+**
+** This routine is designed for use within an assert() statement, to
+** verify the type of an allocation.  For example:
+**
+**     assert( sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
+*/
+SQLITE_PRIVATE int sqlite3MemdebugNoType(const void *p, u8 eType){
+  int rc = 1;
+  if( p && sqlite3GlobalConfig.m.xFree==sqlite3MemFree ){
+    struct MemBlockHdr *pHdr;
+    pHdr = sqlite3MemsysGetHeader(p);
+    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */
+    if( (pHdr->eType&eType)!=0 ){
+      rc = 0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Set the number of backtrace levels kept for each allocation.
+** A value of zero turns off backtracing.  The number is always rounded
+** up to a multiple of 2.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugBacktrace(int depth){
+  if( depth<0 ){ depth = 0; }
+  if( depth>20 ){ depth = 20; }
+  depth = (depth+1)&0xfe;
+  mem.nBacktrace = depth;
+}
+
+SQLITE_PRIVATE void sqlite3MemdebugBacktraceCallback(void (*xBacktrace)(int, int, void **)){
+  mem.xBacktrace = xBacktrace;
+}
+
+/*
+** Set the title string for subsequent allocations.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugSettitle(const char *zTitle){
+  unsigned int n = sqlite3Strlen30(zTitle) + 1;
+  sqlite3_mutex_enter(mem.mutex);
+  if( n>=sizeof(mem.zTitle) ) n = sizeof(mem.zTitle)-1;
+  memcpy(mem.zTitle, zTitle, n);
+  mem.zTitle[n] = 0;
+  mem.nTitle = ROUND8(n);
+  sqlite3_mutex_leave(mem.mutex);
+}
+
+SQLITE_PRIVATE void sqlite3MemdebugSync(){
+  struct MemBlockHdr *pHdr;
+  for(pHdr=mem.pFirst; pHdr; pHdr=pHdr->pNext){
+    void **pBt = (void**)pHdr;
+    pBt -= pHdr->nBacktraceSlots;
+    mem.xBacktrace((int)pHdr->iSize, pHdr->nBacktrace-1, &pBt[1]);
+  }
+}
+
+/*
+** Open the file indicated and write a log of all unfreed memory
+** allocations into that log.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugDump(const char *zFilename){
+  FILE *out;
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  int i;
+  out = fopen(zFilename, "w");
+  if( out==0 ){
+    fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                    zFilename);
+    return;
+  }
+  for(pHdr=mem.pFirst; pHdr; pHdr=pHdr->pNext){
+    char *z = (char*)pHdr;
+    z -= pHdr->nBacktraceSlots*sizeof(void*) + pHdr->nTitle;
+    fprintf(out, "**** %lld bytes at %p from %s ****\n",
+            pHdr->iSize, &pHdr[1], pHdr->nTitle ? z : "???");
+    if( pHdr->nBacktrace ){
+      fflush(out);
+      pBt = (void**)pHdr;
+      pBt -= pHdr->nBacktraceSlots;
+      backtrace_symbols_fd(pBt, pHdr->nBacktrace, fileno(out));
+      fprintf(out, "\n");
+    }
+  }
+  fprintf(out, "COUNTS:\n");
+  for(i=0; i<NCSIZE-1; i++){
+    if( mem.nAlloc[i] ){
+      fprintf(out, "   %5d: %10d %10d %10d\n",
+            i*8, mem.nAlloc[i], mem.nCurrent[i], mem.mxCurrent[i]);
+    }
+  }
+  if( mem.nAlloc[NCSIZE-1] ){
+    fprintf(out, "   %5d: %10d %10d %10d\n",
+             NCSIZE*8-8, mem.nAlloc[NCSIZE-1],
+             mem.nCurrent[NCSIZE-1], mem.mxCurrent[NCSIZE-1]);
+  }
+  fclose(out);
+}
+
+/*
+** Return the number of times sqlite3MemMalloc() has been called.
+*/
+SQLITE_PRIVATE int sqlite3MemdebugMallocCount(){
+  int i;
+  int nTotal = 0;
+  for(i=0; i<NCSIZE; i++){
+    nTotal += mem.nAlloc[i];
+  }
+  return nTotal;
+}
+
+
+#endif /* SQLITE_MEMDEBUG */
+
+/************** End of mem2.c ************************************************/
+/************** Begin file mem3.c ********************************************/
+/*
+** 2007 October 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement a memory
+** allocation subsystem for use by SQLite.
+**
+** This version of the memory allocation subsystem omits all
+** use of malloc(). The SQLite user supplies a block of memory
+** before calling sqlite3_initialize() from which allocations
+** are made and returned by the xMalloc() and xRealloc()
+** implementations. Once sqlite3_initialize() has been called,
+** the amount of memory available to SQLite is fixed and cannot
+** be changed.
+**
+** This version of the memory allocation subsystem is included
+** in the build only if SQLITE_ENABLE_MEMSYS3 is defined.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is only built into the library
+** SQLITE_ENABLE_MEMSYS3 is defined. Defining this symbol does not
+** mean that the library will use a memory-pool by default, just that
+** it is available. The mempool allocator is activated by calling
+** sqlite3_config().
+*/
+#ifdef SQLITE_ENABLE_MEMSYS3
+
+/*
+** Maximum size (in Mem3Blocks) of a "small" chunk.
+*/
+#define MX_SMALL 10
+
+
+/*
+** Number of freelist hash slots
+*/
+#define N_HASH  61
+
+/*
+** A memory allocation (also called a "chunk") consists of two or
+** more blocks where each block is 8 bytes.  The first 8 bytes are
+** a header that is not returned to the user.
+**
+** A chunk is two or more blocks that is either checked out or
+** free.  The first block has format u.hdr.  u.hdr.size4x is 4 times the
+** size of the allocation in blocks if the allocation is free.
+** The u.hdr.size4x&1 bit is true if the chunk is checked out and
+** false if the chunk is on the freelist.  The u.hdr.size4x&2 bit
+** is true if the previous chunk is checked out and false if the
+** previous chunk is free.  The u.hdr.prevSize field is the size of
+** the previous chunk in blocks if the previous chunk is on the
+** freelist. If the previous chunk is checked out, then
+** u.hdr.prevSize can be part of the data for that chunk and should
+** not be read or written.
+**
+** We often identify a chunk by its index in mem3.aPool[].  When
+** this is done, the chunk index refers to the second block of
+** the chunk.  In this way, the first chunk has an index of 1.
+** A chunk index of 0 means "no such chunk" and is the equivalent
+** of a NULL pointer.
+**
+** The second block of free chunks is of the form u.list.  The
+** two fields form a double-linked list of chunks of related sizes.
+** Pointers to the head of the list are stored in mem3.aiSmall[]
+** for smaller chunks and mem3.aiHash[] for larger chunks.
+**
+** The second block of a chunk is user data if the chunk is checked
+** out.  If a chunk is checked out, the user data may extend into
+** the u.hdr.prevSize value of the following chunk.
+*/
+typedef struct Mem3Block Mem3Block;
+struct Mem3Block {
+  union {
+    struct {
+      u32 prevSize;   /* Size of previous chunk in Mem3Block elements */
+      u32 size4x;     /* 4x the size of current chunk in Mem3Block elements */
+    } hdr;
+    struct {
+      u32 next;       /* Index in mem3.aPool[] of next free chunk */
+      u32 prev;       /* Index in mem3.aPool[] of previous free chunk */
+    } list;
+  } u;
+};
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem3".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static SQLITE_WSD struct Mem3Global {
+  /*
+  ** Memory available for allocation. nPool is the size of the array
+  ** (in Mem3Blocks) pointed to by aPool less 2.
+  */
+  u32 nPool;
+  Mem3Block *aPool;
+
+  /*
+  ** True if we are evaluating an out-of-memory callback.
+  */
+  int alarmBusy;
+
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+
+  /*
+  ** The minimum amount of free space that we have seen.
+  */
+  u32 mnKeyBlk;
+
+  /*
+  ** iKeyBlk is the index of the key chunk.  Most new allocations
+  ** occur off of this chunk.  szKeyBlk is the size (in Mem3Blocks)
+  ** of the current key chunk.  iKeyBlk is 0 if there is no key chunk.
+  ** The key chunk is not in either the aiHash[] or aiSmall[].
+  */
+  u32 iKeyBlk;
+  u32 szKeyBlk;
+
+  /*
+  ** Array of lists of free blocks according to the block size
+  ** for smaller chunks, or a hash on the block size for larger
+  ** chunks.
+  */
+  u32 aiSmall[MX_SMALL-1];   /* For sizes 2 through MX_SMALL, inclusive */
+  u32 aiHash[N_HASH];        /* For sizes MX_SMALL+1 and larger */
+} mem3 = { 97535575 };
+
+#define mem3 GLOBAL(struct Mem3Global, mem3)
+
+/*
+** Unlink the chunk at mem3.aPool[i] from list it is currently
+** on.  *pRoot is the list that i is a member of.
+*/
+static void memsys3UnlinkFromList(u32 i, u32 *pRoot){
+  u32 next = mem3.aPool[i].u.list.next;
+  u32 prev = mem3.aPool[i].u.list.prev;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  if( prev==0 ){
+    *pRoot = next;
+  }else{
+    mem3.aPool[prev].u.list.next = next;
+  }
+  if( next ){
+    mem3.aPool[next].u.list.prev = prev;
+  }
+  mem3.aPool[i].u.list.next = 0;
+  mem3.aPool[i].u.list.prev = 0;
+}
+
+/*
+** Unlink the chunk at index i from
+** whatever list is currently a member of.
+*/
+static void memsys3Unlink(u32 i){
+  u32 size, hash;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( (mem3.aPool[i-1].u.hdr.size4x & 1)==0 );
+  assert( i>=1 );
+  size = mem3.aPool[i-1].u.hdr.size4x/4;
+  assert( size==mem3.aPool[i+size-1].u.hdr.prevSize );
+  assert( size>=2 );
+  if( size <= MX_SMALL ){
+    memsys3UnlinkFromList(i, &mem3.aiSmall[size-2]);
+  }else{
+    hash = size % N_HASH;
+    memsys3UnlinkFromList(i, &mem3.aiHash[hash]);
+  }
+}
+
+/*
+** Link the chunk at mem3.aPool[i] so that is on the list rooted
+** at *pRoot.
+*/
+static void memsys3LinkIntoList(u32 i, u32 *pRoot){
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  mem3.aPool[i].u.list.next = *pRoot;
+  mem3.aPool[i].u.list.prev = 0;
+  if( *pRoot ){
+    mem3.aPool[*pRoot].u.list.prev = i;
+  }
+  *pRoot = i;
+}
+
+/*
+** Link the chunk at index i into either the appropriate
+** small chunk list, or into the large chunk hash table.
+*/
+static void memsys3Link(u32 i){
+  u32 size, hash;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( i>=1 );
+  assert( (mem3.aPool[i-1].u.hdr.size4x & 1)==0 );
+  size = mem3.aPool[i-1].u.hdr.size4x/4;
+  assert( size==mem3.aPool[i+size-1].u.hdr.prevSize );
+  assert( size>=2 );
+  if( size <= MX_SMALL ){
+    memsys3LinkIntoList(i, &mem3.aiSmall[size-2]);
+  }else{
+    hash = size % N_HASH;
+    memsys3LinkIntoList(i, &mem3.aiHash[hash]);
+  }
+}
+
+/*
+** If the STATIC_MEM mutex is not already held, obtain it now. The mutex
+** will already be held (obtained by code in malloc.c) if
+** sqlite3GlobalConfig.bMemStat is true.
+*/
+static void memsys3Enter(void){
+  if( sqlite3GlobalConfig.bMemstat==0 && mem3.mutex==0 ){
+    mem3.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+  sqlite3_mutex_enter(mem3.mutex);
+}
+static void memsys3Leave(void){
+  sqlite3_mutex_leave(mem3.mutex);
+}
+
+/*
+** Called when we are unable to satisfy an allocation of nBytes.
+*/
+static void memsys3OutOfMemory(int nByte){
+  if( !mem3.alarmBusy ){
+    mem3.alarmBusy = 1;
+    assert( sqlite3_mutex_held(mem3.mutex) );
+    sqlite3_mutex_leave(mem3.mutex);
+    sqlite3_release_memory(nByte);
+    sqlite3_mutex_enter(mem3.mutex);
+    mem3.alarmBusy = 0;
+  }
+}
+
+
+/*
+** Chunk i is a free chunk that has been unlinked.  Adjust its
+** size parameters for check-out and return a pointer to the
+** user portion of the chunk.
+*/
+static void *memsys3Checkout(u32 i, u32 nBlock){
+  u32 x;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( i>=1 );
+  assert( mem3.aPool[i-1].u.hdr.size4x/4==nBlock );
+  assert( mem3.aPool[i+nBlock-1].u.hdr.prevSize==nBlock );
+  x = mem3.aPool[i-1].u.hdr.size4x;
+  mem3.aPool[i-1].u.hdr.size4x = nBlock*4 | 1 | (x&2);
+  mem3.aPool[i+nBlock-1].u.hdr.prevSize = nBlock;
+  mem3.aPool[i+nBlock-1].u.hdr.size4x |= 2;
+  return &mem3.aPool[i];
+}
+
+/*
+** Carve a piece off of the end of the mem3.iKeyBlk free chunk.
+** Return a pointer to the new allocation.  Or, if the key chunk
+** is not large enough, return 0.
+*/
+static void *memsys3FromKeyBlk(u32 nBlock){
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( mem3.szKeyBlk>=nBlock );
+  if( nBlock>=mem3.szKeyBlk-1 ){
+    /* Use the entire key chunk */
+    void *p = memsys3Checkout(mem3.iKeyBlk, mem3.szKeyBlk);
+    mem3.iKeyBlk = 0;
+    mem3.szKeyBlk = 0;
+    mem3.mnKeyBlk = 0;
+    return p;
+  }else{
+    /* Split the key block.  Return the tail. */
+    u32 newi, x;
+    newi = mem3.iKeyBlk + mem3.szKeyBlk - nBlock;
+    assert( newi > mem3.iKeyBlk+1 );
+    mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.prevSize = nBlock;
+    mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.size4x |= 2;
+    mem3.aPool[newi-1].u.hdr.size4x = nBlock*4 + 1;
+    mem3.szKeyBlk -= nBlock;
+    mem3.aPool[newi-1].u.hdr.prevSize = mem3.szKeyBlk;
+    x = mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x & 2;
+    mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x = mem3.szKeyBlk*4 | x;
+    if( mem3.szKeyBlk < mem3.mnKeyBlk ){
+      mem3.mnKeyBlk = mem3.szKeyBlk;
+    }
+    return (void*)&mem3.aPool[newi];
+  }
+}
+
+/*
+** *pRoot is the head of a list of free chunks of the same size
+** or same size hash.  In other words, *pRoot is an entry in either
+** mem3.aiSmall[] or mem3.aiHash[].
+**
+** This routine examines all entries on the given list and tries
+** to coalesce each entries with adjacent free chunks.
+**
+** If it sees a chunk that is larger than mem3.iKeyBlk, it replaces
+** the current mem3.iKeyBlk with the new larger chunk.  In order for
+** this mem3.iKeyBlk replacement to work, the key chunk must be
+** linked into the hash tables.  That is not the normal state of
+** affairs, of course.  The calling routine must link the key
+** chunk before invoking this routine, then must unlink the (possibly
+** changed) key chunk once this routine has finished.
+*/
+static void memsys3Merge(u32 *pRoot){
+  u32 iNext, prev, size, i, x;
+
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  for(i=*pRoot; i>0; i=iNext){
+    iNext = mem3.aPool[i].u.list.next;
+    size = mem3.aPool[i-1].u.hdr.size4x;
+    assert( (size&1)==0 );
+    if( (size&2)==0 ){
+      memsys3UnlinkFromList(i, pRoot);
+      assert( i > mem3.aPool[i-1].u.hdr.prevSize );
+      prev = i - mem3.aPool[i-1].u.hdr.prevSize;
+      if( prev==iNext ){
+        iNext = mem3.aPool[prev].u.list.next;
+      }
+      memsys3Unlink(prev);
+      size = i + size/4 - prev;
+      x = mem3.aPool[prev-1].u.hdr.size4x & 2;
+      mem3.aPool[prev-1].u.hdr.size4x = size*4 | x;
+      mem3.aPool[prev+size-1].u.hdr.prevSize = size;
+      memsys3Link(prev);
+      i = prev;
+    }else{
+      size /= 4;
+    }
+    if( size>mem3.szKeyBlk ){
+      mem3.iKeyBlk = i;
+      mem3.szKeyBlk = size;
+    }
+  }
+}
+
+/*
+** Return a block of memory of at least nBytes in size.
+** Return NULL if unable.
+**
+** This function assumes that the necessary mutexes, if any, are
+** already held by the caller. Hence "Unsafe".
+*/
+static void *memsys3MallocUnsafe(int nByte){
+  u32 i;
+  u32 nBlock;
+  u32 toFree;
+
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( sizeof(Mem3Block)==8 );
+  if( nByte<=12 ){
+    nBlock = 2;
+  }else{
+    nBlock = (nByte + 11)/8;
+  }
+  assert( nBlock>=2 );
+
+  /* STEP 1:
+  ** Look for an entry of the correct size in either the small
+  ** chunk table or in the large chunk hash table.  This is
+  ** successful most of the time (about 9 times out of 10).
+  */
+  if( nBlock <= MX_SMALL ){
+    i = mem3.aiSmall[nBlock-2];
+    if( i>0 ){
+      memsys3UnlinkFromList(i, &mem3.aiSmall[nBlock-2]);
+      return memsys3Checkout(i, nBlock);
+    }
+  }else{
+    int hash = nBlock % N_HASH;
+    for(i=mem3.aiHash[hash]; i>0; i=mem3.aPool[i].u.list.next){
+      if( mem3.aPool[i-1].u.hdr.size4x/4==nBlock ){
+        memsys3UnlinkFromList(i, &mem3.aiHash[hash]);
+        return memsys3Checkout(i, nBlock);
+      }
+    }
+  }
+
+  /* STEP 2:
+  ** Try to satisfy the allocation by carving a piece off of the end
+  ** of the key chunk.  This step usually works if step 1 fails.
+  */
+  if( mem3.szKeyBlk>=nBlock ){
+    return memsys3FromKeyBlk(nBlock);
+  }
+
+
+  /* STEP 3:
+  ** Loop through the entire memory pool.  Coalesce adjacent free
+  ** chunks.  Recompute the key chunk as the largest free chunk.
+  ** Then try again to satisfy the allocation by carving a piece off
+  ** of the end of the key chunk.  This step happens very
+  ** rarely (we hope!)
+  */
+  for(toFree=nBlock*16; toFree<(mem3.nPool*16); toFree *= 2){
+    memsys3OutOfMemory(toFree);
+    if( mem3.iKeyBlk ){
+      memsys3Link(mem3.iKeyBlk);
+      mem3.iKeyBlk = 0;
+      mem3.szKeyBlk = 0;
+    }
+    for(i=0; i<N_HASH; i++){
+      memsys3Merge(&mem3.aiHash[i]);
+    }
+    for(i=0; i<MX_SMALL-1; i++){
+      memsys3Merge(&mem3.aiSmall[i]);
+    }
+    if( mem3.szKeyBlk ){
+      memsys3Unlink(mem3.iKeyBlk);
+      if( mem3.szKeyBlk>=nBlock ){
+        return memsys3FromKeyBlk(nBlock);
+      }
+    }
+  }
+
+  /* If none of the above worked, then we fail. */
+  return 0;
+}
+
+/*
+** Free an outstanding memory allocation.
+**
+** This function assumes that the necessary mutexes, if any, are
+** already held by the caller. Hence "Unsafe".
+*/
+static void memsys3FreeUnsafe(void *pOld){
+  Mem3Block *p = (Mem3Block*)pOld;
+  int i;
+  u32 size, x;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( p>mem3.aPool && p<&mem3.aPool[mem3.nPool] );
+  i = p - mem3.aPool;
+  assert( (mem3.aPool[i-1].u.hdr.size4x&1)==1 );
+  size = mem3.aPool[i-1].u.hdr.size4x/4;
+  assert( i+size<=mem3.nPool+1 );
+  mem3.aPool[i-1].u.hdr.size4x &= ~1;
+  mem3.aPool[i+size-1].u.hdr.prevSize = size;
+  mem3.aPool[i+size-1].u.hdr.size4x &= ~2;
+  memsys3Link(i);
+
+  /* Try to expand the key using the newly freed chunk */
+  if( mem3.iKeyBlk ){
+    while( (mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x&2)==0 ){
+      size = mem3.aPool[mem3.iKeyBlk-1].u.hdr.prevSize;
+      mem3.iKeyBlk -= size;
+      mem3.szKeyBlk += size;
+      memsys3Unlink(mem3.iKeyBlk);
+      x = mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x & 2;
+      mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x = mem3.szKeyBlk*4 | x;
+      mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.prevSize = mem3.szKeyBlk;
+    }
+    x = mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x & 2;
+    while( (mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.size4x&1)==0 ){
+      memsys3Unlink(mem3.iKeyBlk+mem3.szKeyBlk);
+      mem3.szKeyBlk += mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.size4x/4;
+      mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x = mem3.szKeyBlk*4 | x;
+      mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.prevSize = mem3.szKeyBlk;
+    }
+  }
+}
+
+/*
+** Return the size of an outstanding allocation, in bytes.  The
+** size returned omits the 8-byte header overhead.  This only
+** works for chunks that are currently checked out.
+*/
+static int memsys3Size(void *p){
+  Mem3Block *pBlock;
+  assert( p!=0 );
+  pBlock = (Mem3Block*)p;
+  assert( (pBlock[-1].u.hdr.size4x&1)!=0 );
+  return (pBlock[-1].u.hdr.size4x&~3)*2 - 4;
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int memsys3Roundup(int n){
+  if( n<=12 ){
+    return 12;
+  }else{
+    return ((n+11)&~7) - 4;
+  }
+}
+
+/*
+** Allocate nBytes of memory.
+*/
+static void *memsys3Malloc(int nBytes){
+  sqlite3_int64 *p;
+  assert( nBytes>0 );          /* malloc.c filters out 0 byte requests */
+  memsys3Enter();
+  p = memsys3MallocUnsafe(nBytes);
+  memsys3Leave();
+  return (void*)p;
+}
+
+/*
+** Free memory.
+*/
+static void memsys3Free(void *pPrior){
+  assert( pPrior );
+  memsys3Enter();
+  memsys3FreeUnsafe(pPrior);
+  memsys3Leave();
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+static void *memsys3Realloc(void *pPrior, int nBytes){
+  int nOld;
+  void *p;
+  if( pPrior==0 ){
+    return sqlite3_malloc(nBytes);
+  }
+  if( nBytes<=0 ){
+    sqlite3_free(pPrior);
+    return 0;
+  }
+  nOld = memsys3Size(pPrior);
+  if( nBytes<=nOld && nBytes>=nOld-128 ){
+    return pPrior;
+  }
+  memsys3Enter();
+  p = memsys3MallocUnsafe(nBytes);
+  if( p ){
+    if( nOld<nBytes ){
+      memcpy(p, pPrior, nOld);
+    }else{
+      memcpy(p, pPrior, nBytes);
+    }
+    memsys3FreeUnsafe(pPrior);
+  }
+  memsys3Leave();
+  return p;
+}
+
+/*
+** Initialize this module.
+*/
+static int memsys3Init(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  if( !sqlite3GlobalConfig.pHeap ){
+    return SQLITE_ERROR;
+  }
+
+  /* Store a pointer to the memory block in global structure mem3. */
+  assert( sizeof(Mem3Block)==8 );
+  mem3.aPool = (Mem3Block *)sqlite3GlobalConfig.pHeap;
+  mem3.nPool = (sqlite3GlobalConfig.nHeap / sizeof(Mem3Block)) - 2;
+
+  /* Initialize the key block. */
+  mem3.szKeyBlk = mem3.nPool;
+  mem3.mnKeyBlk = mem3.szKeyBlk;
+  mem3.iKeyBlk = 1;
+  mem3.aPool[0].u.hdr.size4x = (mem3.szKeyBlk<<2) + 2;
+  mem3.aPool[mem3.nPool].u.hdr.prevSize = mem3.nPool;
+  mem3.aPool[mem3.nPool].u.hdr.size4x = 1;
+
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize this module.
+*/
+static void memsys3Shutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  mem3.mutex = 0;
+  return;
+}
+
+
+
+/*
+** Open the file indicated and write a log of all unfreed memory
+** allocations into that log.
+*/
+SQLITE_PRIVATE void sqlite3Memsys3Dump(const char *zFilename){
+#ifdef SQLITE_DEBUG
+  FILE *out;
+  u32 i, j;
+  u32 size;
+  if( zFilename==0 || zFilename[0]==0 ){
+    out = stdout;
+  }else{
+    out = fopen(zFilename, "w");
+    if( out==0 ){
+      fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                      zFilename);
+      return;
+    }
+  }
+  memsys3Enter();
+  fprintf(out, "CHUNKS:\n");
+  for(i=1; i<=mem3.nPool; i+=size/4){
+    size = mem3.aPool[i-1].u.hdr.size4x;
+    if( size/4<=1 ){
+      fprintf(out, "%p size error\n", &mem3.aPool[i]);
+      assert( 0 );
+      break;
+    }
+    if( (size&1)==0 && mem3.aPool[i+size/4-1].u.hdr.prevSize!=size/4 ){
+      fprintf(out, "%p tail size does not match\n", &mem3.aPool[i]);
+      assert( 0 );
+      break;
+    }
+    if( ((mem3.aPool[i+size/4-1].u.hdr.size4x&2)>>1)!=(size&1) ){
+      fprintf(out, "%p tail checkout bit is incorrect\n", &mem3.aPool[i]);
+      assert( 0 );
+      break;
+    }
+    if( size&1 ){
+      fprintf(out, "%p %6d bytes checked out\n", &mem3.aPool[i], (size/4)*8-8);
+    }else{
+      fprintf(out, "%p %6d bytes free%s\n", &mem3.aPool[i], (size/4)*8-8,
+                  i==mem3.iKeyBlk ? " **key**" : "");
+    }
+  }
+  for(i=0; i<MX_SMALL-1; i++){
+    if( mem3.aiSmall[i]==0 ) continue;
+    fprintf(out, "small(%2d):", i);
+    for(j = mem3.aiSmall[i]; j>0; j=mem3.aPool[j].u.list.next){
+      fprintf(out, " %p(%d)", &mem3.aPool[j],
+              (mem3.aPool[j-1].u.hdr.size4x/4)*8-8);
+    }
+    fprintf(out, "\n");
+  }
+  for(i=0; i<N_HASH; i++){
+    if( mem3.aiHash[i]==0 ) continue;
+    fprintf(out, "hash(%2d):", i);
+    for(j = mem3.aiHash[i]; j>0; j=mem3.aPool[j].u.list.next){
+      fprintf(out, " %p(%d)", &mem3.aPool[j],
+              (mem3.aPool[j-1].u.hdr.size4x/4)*8-8);
+    }
+    fprintf(out, "\n");
+  }
+  fprintf(out, "key=%d\n", mem3.iKeyBlk);
+  fprintf(out, "nowUsed=%d\n", mem3.nPool*8 - mem3.szKeyBlk*8);
+  fprintf(out, "mxUsed=%d\n", mem3.nPool*8 - mem3.mnKeyBlk*8);
+  sqlite3_mutex_leave(mem3.mutex);
+  if( out==stdout ){
+    fflush(stdout);
+  }else{
+    fclose(out);
+  }
+#else
+  UNUSED_PARAMETER(zFilename);
+#endif
+}
+
+/*
+** This routine is the only routine in this file with external
+** linkage.
+**
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file. The
+** arguments specify the block of memory to manage.
+**
+** This routine is only called by sqlite3_config(), and therefore
+** is not required to be threadsafe (it is not).
+*/
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys3(void){
+  static const sqlite3_mem_methods mempoolMethods = {
+     memsys3Malloc,
+     memsys3Free,
+     memsys3Realloc,
+     memsys3Size,
+     memsys3Roundup,
+     memsys3Init,
+     memsys3Shutdown,
+     0
+  };
+  return &mempoolMethods;
+}
+
+#endif /* SQLITE_ENABLE_MEMSYS3 */
+
+/************** End of mem3.c ************************************************/
+/************** Begin file mem5.c ********************************************/
+/*
+** 2007 October 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement a memory
+** allocation subsystem for use by SQLite.
+**
+** This version of the memory allocation subsystem omits all
+** use of malloc(). The application gives SQLite a block of memory
+** before calling sqlite3_initialize() from which allocations
+** are made and returned by the xMalloc() and xRealloc()
+** implementations. Once sqlite3_initialize() has been called,
+** the amount of memory available to SQLite is fixed and cannot
+** be changed.
+**
+** This version of the memory allocation subsystem is included
+** in the build only if SQLITE_ENABLE_MEMSYS5 is defined.
+**
+** This memory allocator uses the following algorithm:
+**
+**   1.  All memory allocation sizes are rounded up to a power of 2.
+**
+**   2.  If two adjacent free blocks are the halves of a larger block,
+**       then the two blocks are coalesced into the single larger block.
+**
+**   3.  New memory is allocated from the first available free block.
+**
+** This algorithm is described in: J. M. Robson. "Bounds for Some Functions
+** Concerning Dynamic Storage Allocation". Journal of the Association for
+** Computing Machinery, Volume 21, Number 8, July 1974, pages 491-499.
+**
+** Let n be the size of the largest allocation divided by the minimum
+** allocation size (after rounding all sizes up to a power of 2.)  Let M
+** be the maximum amount of memory ever outstanding at one time.  Let
+** N be the total amount of memory available for allocation.  Robson
+** proved that this memory allocator will never breakdown due to
+** fragmentation as long as the following constraint holds:
+**
+**      N >=  M*(1 + log2(n)/2) - n + 1
+**
+** The sqlite3_status() logic tracks the maximum values of n and M so
+** that an application can, at any time, verify this constraint.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is used only when
+** SQLITE_ENABLE_MEMSYS5 is defined.
+*/
+#ifdef SQLITE_ENABLE_MEMSYS5
+
+/*
+** A minimum allocation is an instance of the following structure.
+** Larger allocations are an array of these structures where the
+** size of the array is a power of 2.
+**
+** The size of this object must be a power of two.  That fact is
+** verified in memsys5Init().
+*/
+typedef struct Mem5Link Mem5Link;
+struct Mem5Link {
+  int next;       /* Index of next free chunk */
+  int prev;       /* Index of previous free chunk */
+};
+
+/*
+** Maximum size of any allocation is ((1<<LOGMAX)*mem5.szAtom). Since
+** mem5.szAtom is always at least 8 and 32-bit integers are used,
+** it is not actually possible to reach this limit.
+*/
+#define LOGMAX 30
+
+/*
+** Masks used for mem5.aCtrl[] elements.
+*/
+#define CTRL_LOGSIZE  0x1f    /* Log2 Size of this block */
+#define CTRL_FREE     0x20    /* True if not checked out */
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem5".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static SQLITE_WSD struct Mem5Global {
+  /*
+  ** Memory available for allocation
+  */
+  int szAtom;      /* Smallest possible allocation in bytes */
+  int nBlock;      /* Number of szAtom sized blocks in zPool */
+  u8 *zPool;       /* Memory available to be allocated */
+
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /*
+  ** Performance statistics
+  */
+  u64 nAlloc;         /* Total number of calls to malloc */
+  u64 totalAlloc;     /* Total of all malloc calls - includes internal frag */
+  u64 totalExcess;    /* Total internal fragmentation */
+  u32 currentOut;     /* Current checkout, including internal fragmentation */
+  u32 currentCount;   /* Current number of distinct checkouts */
+  u32 maxOut;         /* Maximum instantaneous currentOut */
+  u32 maxCount;       /* Maximum instantaneous currentCount */
+  u32 maxRequest;     /* Largest allocation (exclusive of internal frag) */
+#endif
+
+  /*
+  ** Lists of free blocks.  aiFreelist[0] is a list of free blocks of
+  ** size mem5.szAtom.  aiFreelist[1] holds blocks of size szAtom*2.
+  ** aiFreelist[2] holds free blocks of size szAtom*4.  And so forth.
+  */
+  int aiFreelist[LOGMAX+1];
+
+  /*
+  ** Space for tracking which blocks are checked out and the size
+  ** of each block.  One byte per block.
+  */
+  u8 *aCtrl;
+
+} mem5;
+
+/*
+** Access the static variable through a macro for SQLITE_OMIT_WSD.
+*/
+#define mem5 GLOBAL(struct Mem5Global, mem5)
+
+/*
+** Assuming mem5.zPool is divided up into an array of Mem5Link
+** structures, return a pointer to the idx-th such link.
+*/
+#define MEM5LINK(idx) ((Mem5Link *)(&mem5.zPool[(idx)*mem5.szAtom]))
+
+/*
+** Unlink the chunk at mem5.aPool[i] from list it is currently
+** on.  It should be found on mem5.aiFreelist[iLogsize].
+*/
+static void memsys5Unlink(int i, int iLogsize){
+  int next, prev;
+  assert( i>=0 && i<mem5.nBlock );
+  assert( iLogsize>=0 && iLogsize<=LOGMAX );
+  assert( (mem5.aCtrl[i] & CTRL_LOGSIZE)==iLogsize );
+
+  next = MEM5LINK(i)->next;
+  prev = MEM5LINK(i)->prev;
+  if( prev<0 ){
+    mem5.aiFreelist[iLogsize] = next;
+  }else{
+    MEM5LINK(prev)->next = next;
+  }
+  if( next>=0 ){
+    MEM5LINK(next)->prev = prev;
+  }
+}
+
+/*
+** Link the chunk at mem5.aPool[i] so that is on the iLogsize
+** free list.
+*/
+static void memsys5Link(int i, int iLogsize){
+  int x;
+  assert( sqlite3_mutex_held(mem5.mutex) );
+  assert( i>=0 && i<mem5.nBlock );
+  assert( iLogsize>=0 && iLogsize<=LOGMAX );
+  assert( (mem5.aCtrl[i] & CTRL_LOGSIZE)==iLogsize );
+
+  x = MEM5LINK(i)->next = mem5.aiFreelist[iLogsize];
+  MEM5LINK(i)->prev = -1;
+  if( x>=0 ){
+    assert( x<mem5.nBlock );
+    MEM5LINK(x)->prev = i;
+  }
+  mem5.aiFreelist[iLogsize] = i;
+}
+
+/*
+** Obtain or release the mutex needed to access global data structures.
+*/
+static void memsys5Enter(void){
+  sqlite3_mutex_enter(mem5.mutex);
+}
+static void memsys5Leave(void){
+  sqlite3_mutex_leave(mem5.mutex);
+}
+
+/*
+** Return the size of an outstanding allocation, in bytes.
+** This only works for chunks that are currently checked out.
+*/
+static int memsys5Size(void *p){
+  int iSize, i;
+  assert( p!=0 );
+  i = (int)(((u8 *)p-mem5.zPool)/mem5.szAtom);
+  assert( i>=0 && i<mem5.nBlock );
+  iSize = mem5.szAtom * (1 << (mem5.aCtrl[i]&CTRL_LOGSIZE));
+  return iSize;
+}
+
+/*
+** Return a block of memory of at least nBytes in size.
+** Return NULL if unable.  Return NULL if nBytes==0.
+**
+** The caller guarantees that nByte is positive.
+**
+** The caller has obtained a mutex prior to invoking this
+** routine so there is never any chance that two or more
+** threads can be in this routine at the same time.
+*/
+static void *memsys5MallocUnsafe(int nByte){
+  int i;           /* Index of a mem5.aPool[] slot */
+  int iBin;        /* Index into mem5.aiFreelist[] */
+  int iFullSz;     /* Size of allocation rounded up to power of 2 */
+  int iLogsize;    /* Log2 of iFullSz/POW2_MIN */
+
+  /* nByte must be a positive */
+  assert( nByte>0 );
+
+  /* No more than 1GiB per allocation */
+  if( nByte > 0x40000000 ) return 0;
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /* Keep track of the maximum allocation request.  Even unfulfilled
+  ** requests are counted */
+  if( (u32)nByte>mem5.maxRequest ){
+    mem5.maxRequest = nByte;
+  }
+#endif
+
+
+  /* Round nByte up to the next valid power of two */
+  for(iFullSz=mem5.szAtom,iLogsize=0; iFullSz<nByte; iFullSz*=2,iLogsize++){}
+
+  /* Make sure mem5.aiFreelist[iLogsize] contains at least one free
+  ** block.  If not, then split a block of the next larger power of
+  ** two in order to create a new free block of size iLogsize.
+  */
+  for(iBin=iLogsize; iBin<=LOGMAX && mem5.aiFreelist[iBin]<0; iBin++){}
+  if( iBin>LOGMAX ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes", nByte);
+    return 0;
+  }
+  i = mem5.aiFreelist[iBin];
+  memsys5Unlink(i, iBin);
+  while( iBin>iLogsize ){
+    int newSize;
+
+    iBin--;
+    newSize = 1 << iBin;
+    mem5.aCtrl[i+newSize] = CTRL_FREE | iBin;
+    memsys5Link(i+newSize, iBin);
+  }
+  mem5.aCtrl[i] = iLogsize;
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /* Update allocator performance statistics. */
+  mem5.nAlloc++;
+  mem5.totalAlloc += iFullSz;
+  mem5.totalExcess += iFullSz - nByte;
+  mem5.currentCount++;
+  mem5.currentOut += iFullSz;
+  if( mem5.maxCount<mem5.currentCount ) mem5.maxCount = mem5.currentCount;
+  if( mem5.maxOut<mem5.currentOut ) mem5.maxOut = mem5.currentOut;
+#endif
+
+#ifdef SQLITE_DEBUG
+  /* Make sure the allocated memory does not assume that it is set to zero
+  ** or retains a value from a previous allocation */
+  memset(&mem5.zPool[i*mem5.szAtom], 0xAA, iFullSz);
+#endif
+
+  /* Return a pointer to the allocated memory. */
+  return (void*)&mem5.zPool[i*mem5.szAtom];
+}
+
+/*
+** Free an outstanding memory allocation.
+*/
+static void memsys5FreeUnsafe(void *pOld){
+  u32 size, iLogsize;
+  int iBlock;
+
+  /* Set iBlock to the index of the block pointed to by pOld in
+  ** the array of mem5.szAtom byte blocks pointed to by mem5.zPool.
+  */
+  iBlock = (int)(((u8 *)pOld-mem5.zPool)/mem5.szAtom);
+
+  /* Check that the pointer pOld points to a valid, non-free block. */
+  assert( iBlock>=0 && iBlock<mem5.nBlock );
+  assert( ((u8 *)pOld-mem5.zPool)%mem5.szAtom==0 );
+  assert( (mem5.aCtrl[iBlock] & CTRL_FREE)==0 );
+
+  iLogsize = mem5.aCtrl[iBlock] & CTRL_LOGSIZE;
+  size = 1<<iLogsize;
+  assert( iBlock+size-1<(u32)mem5.nBlock );
+
+  mem5.aCtrl[iBlock] |= CTRL_FREE;
+  mem5.aCtrl[iBlock+size-1] |= CTRL_FREE;
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  assert( mem5.currentCount>0 );
+  assert( mem5.currentOut>=(size*mem5.szAtom) );
+  mem5.currentCount--;
+  mem5.currentOut -= size*mem5.szAtom;
+  assert( mem5.currentOut>0 || mem5.currentCount==0 );
+  assert( mem5.currentCount>0 || mem5.currentOut==0 );
+#endif
+
+  mem5.aCtrl[iBlock] = CTRL_FREE | iLogsize;
+  while( ALWAYS(iLogsize<LOGMAX) ){
+    int iBuddy;
+    if( (iBlock>>iLogsize) & 1 ){
+      iBuddy = iBlock - size;
+      assert( iBuddy>=0 );
+    }else{
+      iBuddy = iBlock + size;
+      if( iBuddy>=mem5.nBlock ) break;
+    }
+    if( mem5.aCtrl[iBuddy]!=(CTRL_FREE | iLogsize) ) break;
+    memsys5Unlink(iBuddy, iLogsize);
+    iLogsize++;
+    if( iBuddy<iBlock ){
+      mem5.aCtrl[iBuddy] = CTRL_FREE | iLogsize;
+      mem5.aCtrl[iBlock] = 0;
+      iBlock = iBuddy;
+    }else{
+      mem5.aCtrl[iBlock] = CTRL_FREE | iLogsize;
+      mem5.aCtrl[iBuddy] = 0;
+    }
+    size *= 2;
+  }
+
+#ifdef SQLITE_DEBUG
+  /* Overwrite freed memory with the 0x55 bit pattern to verify that it is
+  ** not used after being freed */
+  memset(&mem5.zPool[iBlock*mem5.szAtom], 0x55, size);
+#endif
+
+  memsys5Link(iBlock, iLogsize);
+}
+
+/*
+** Allocate nBytes of memory.
+*/
+static void *memsys5Malloc(int nBytes){
+  sqlite3_int64 *p = 0;
+  if( nBytes>0 ){
+    memsys5Enter();
+    p = memsys5MallocUnsafe(nBytes);
+    memsys5Leave();
+  }
+  return (void*)p;
+}
+
+/*
+** Free memory.
+**
+** The outer layer memory allocator prevents this routine from
+** being called with pPrior==0.
+*/
+static void memsys5Free(void *pPrior){
+  assert( pPrior!=0 );
+  memsys5Enter();
+  memsys5FreeUnsafe(pPrior);
+  memsys5Leave();
+}
+
+/*
+** Change the size of an existing memory allocation.
+**
+** The outer layer memory allocator prevents this routine from
+** being called with pPrior==0.
+**
+** nBytes is always a value obtained from a prior call to
+** memsys5Round().  Hence nBytes is always a non-negative power
+** of two.  If nBytes==0 that means that an oversize allocation
+** (an allocation larger than 0x40000000) was requested and this
+** routine should return 0 without freeing pPrior.
+*/
+static void *memsys5Realloc(void *pPrior, int nBytes){
+  int nOld;
+  void *p;
+  assert( pPrior!=0 );
+  assert( (nBytes&(nBytes-1))==0 );  /* EV: R-46199-30249 */
+  assert( nBytes>=0 );
+  if( nBytes==0 ){
+    return 0;
+  }
+  nOld = memsys5Size(pPrior);
+  if( nBytes<=nOld ){
+    return pPrior;
+  }
+  p = memsys5Malloc(nBytes);
+  if( p ){
+    memcpy(p, pPrior, nOld);
+    memsys5Free(pPrior);
+  }
+  return p;
+}
+
+/*
+** Round up a request size to the next valid allocation size.  If
+** the allocation is too large to be handled by this allocation system,
+** return 0.
+**
+** All allocations must be a power of two and must be expressed by a
+** 32-bit signed integer.  Hence the largest allocation is 0x40000000
+** or 1073741824 bytes.
+*/
+static int memsys5Roundup(int n){
+  int iFullSz;
+  if( n<=mem5.szAtom*2 ){
+    if( n<=mem5.szAtom ) return mem5.szAtom;
+    return mem5.szAtom*2;
+  }
+  if( n>0x10000000 ){
+    if( n>0x40000000 ) return 0;
+    if( n>0x20000000 ) return 0x40000000;
+    return 0x20000000;
+  }
+  for(iFullSz=mem5.szAtom*8; iFullSz<n; iFullSz *= 4);
+  if( (iFullSz/2)>=(i64)n ) return iFullSz/2;
+  return iFullSz;
+}
+
+/*
+** Return the ceiling of the logarithm base 2 of iValue.
+**
+** Examples:   memsys5Log(1) -> 0
+**             memsys5Log(2) -> 1
+**             memsys5Log(4) -> 2
+**             memsys5Log(5) -> 3
+**             memsys5Log(8) -> 3
+**             memsys5Log(9) -> 4
+*/
+static int memsys5Log(int iValue){
+  int iLog;
+  for(iLog=0; (iLog<(int)((sizeof(int)*8)-1)) && (1<<iLog)<iValue; iLog++);
+  return iLog;
+}
+
+/*
+** Initialize the memory allocator.
+**
+** This routine is not threadsafe.  The caller must be holding a mutex
+** to prevent multiple threads from entering at the same time.
+*/
+static int memsys5Init(void *NotUsed){
+  int ii;            /* Loop counter */
+  int nByte;         /* Number of bytes of memory available to this allocator */
+  u8 *zByte;         /* Memory usable by this allocator */
+  int nMinLog;       /* Log base 2 of minimum allocation size in bytes */
+  int iOffset;       /* An offset into mem5.aCtrl[] */
+
+  UNUSED_PARAMETER(NotUsed);
+
+  /* For the purposes of this routine, disable the mutex */
+  mem5.mutex = 0;
+
+  /* The size of a Mem5Link object must be a power of two.  Verify that
+  ** this is case.
+  */
+  assert( (sizeof(Mem5Link)&(sizeof(Mem5Link)-1))==0 );
+
+  nByte = sqlite3GlobalConfig.nHeap;
+  zByte = (u8*)sqlite3GlobalConfig.pHeap;
+  assert( zByte!=0 );  /* sqlite3_config() does not allow otherwise */
+
+  /* boundaries on sqlite3GlobalConfig.mnReq are enforced in sqlite3_config() */
+  nMinLog = memsys5Log(sqlite3GlobalConfig.mnReq);
+  mem5.szAtom = (1<<nMinLog);
+  while( (int)sizeof(Mem5Link)>mem5.szAtom ){
+    mem5.szAtom = mem5.szAtom << 1;
+  }
+
+  mem5.nBlock = (nByte / (mem5.szAtom+sizeof(u8)));
+  mem5.zPool = zByte;
+  mem5.aCtrl = (u8 *)&mem5.zPool[mem5.nBlock*mem5.szAtom];
+
+  for(ii=0; ii<=LOGMAX; ii++){
+    mem5.aiFreelist[ii] = -1;
+  }
+
+  iOffset = 0;
+  for(ii=LOGMAX; ii>=0; ii--){
+    int nAlloc = (1<<ii);
+    if( (iOffset+nAlloc)<=mem5.nBlock ){
+      mem5.aCtrl[iOffset] = ii | CTRL_FREE;
+      memsys5Link(iOffset, ii);
+      iOffset += nAlloc;
+    }
+    assert((iOffset+nAlloc)>mem5.nBlock);
+  }
+
+  /* If a mutex is required for normal operation, allocate one */
+  if( sqlite3GlobalConfig.bMemstat==0 ){
+    mem5.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize this module.
+*/
+static void memsys5Shutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  mem5.mutex = 0;
+  return;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Open the file indicated and write a log of all unfreed memory
+** allocations into that log.
+*/
+SQLITE_PRIVATE void sqlite3Memsys5Dump(const char *zFilename){
+  FILE *out;
+  int i, j, n;
+  int nMinLog;
+
+  if( zFilename==0 || zFilename[0]==0 ){
+    out = stdout;
+  }else{
+    out = fopen(zFilename, "w");
+    if( out==0 ){
+      fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                      zFilename);
+      return;
+    }
+  }
+  memsys5Enter();
+  nMinLog = memsys5Log(mem5.szAtom);
+  for(i=0; i<=LOGMAX && i+nMinLog<32; i++){
+    for(n=0, j=mem5.aiFreelist[i]; j>=0; j = MEM5LINK(j)->next, n++){}
+    fprintf(out, "freelist items of size %d: %d\n", mem5.szAtom << i, n);
+  }
+  fprintf(out, "mem5.nAlloc       = %llu\n", mem5.nAlloc);
+  fprintf(out, "mem5.totalAlloc   = %llu\n", mem5.totalAlloc);
+  fprintf(out, "mem5.totalExcess  = %llu\n", mem5.totalExcess);
+  fprintf(out, "mem5.currentOut   = %u\n", mem5.currentOut);
+  fprintf(out, "mem5.currentCount = %u\n", mem5.currentCount);
+  fprintf(out, "mem5.maxOut       = %u\n", mem5.maxOut);
+  fprintf(out, "mem5.maxCount     = %u\n", mem5.maxCount);
+  fprintf(out, "mem5.maxRequest   = %u\n", mem5.maxRequest);
+  memsys5Leave();
+  if( out==stdout ){
+    fflush(stdout);
+  }else{
+    fclose(out);
+  }
+}
+#endif
+
+/*
+** This routine is the only routine in this file with external
+** linkage. It returns a pointer to a static sqlite3_mem_methods
+** struct populated with the memsys5 methods.
+*/
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys5(void){
+  static const sqlite3_mem_methods memsys5Methods = {
+     memsys5Malloc,
+     memsys5Free,
+     memsys5Realloc,
+     memsys5Size,
+     memsys5Roundup,
+     memsys5Init,
+     memsys5Shutdown,
+     0
+  };
+  return &memsys5Methods;
+}
+
+#endif /* SQLITE_ENABLE_MEMSYS5 */
+
+/************** End of mem5.c ************************************************/
+/************** Begin file mutex.c *******************************************/
+/*
+** 2007 August 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes.
+**
+** This file contains code that is common across all mutex implementations.
+*/
+/* #include "sqliteInt.h" */
+
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_MUTEX_OMIT)
+/*
+** For debugging purposes, record when the mutex subsystem is initialized
+** and uninitialized so that we can assert() if there is an attempt to
+** allocate a mutex while the system is uninitialized.
+*/
+static SQLITE_WSD int mutexIsInit = 0;
+#endif /* SQLITE_DEBUG && !defined(SQLITE_MUTEX_OMIT) */
+
+
+#ifndef SQLITE_MUTEX_OMIT
+
+#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
+/*
+** This block (enclosed by SQLITE_ENABLE_MULTITHREADED_CHECKS) contains
+** the implementation of a wrapper around the system default mutex
+** implementation (sqlite3DefaultMutex()).
+**
+** Most calls are passed directly through to the underlying default
+** mutex implementation. Except, if a mutex is configured by calling
+** sqlite3MutexWarnOnContention() on it, then if contention is ever
+** encountered within xMutexEnter() a warning is emitted via sqlite3_log().
+**
+** This type of mutex is used as the database handle mutex when testing
+** apps that usually use SQLITE_CONFIG_MULTITHREAD mode.
+*/
+
+/*
+** Type for all mutexes used when SQLITE_ENABLE_MULTITHREADED_CHECKS
+** is defined. Variable CheckMutex.mutex is a pointer to the real mutex
+** allocated by the system mutex implementation. Variable iType is usually set
+** to the type of mutex requested - SQLITE_MUTEX_RECURSIVE, SQLITE_MUTEX_FAST
+** or one of the static mutex identifiers. Or, if this is a recursive mutex
+** that has been configured using sqlite3MutexWarnOnContention(), it is
+** set to SQLITE_MUTEX_WARNONCONTENTION.
+*/
+typedef struct CheckMutex CheckMutex;
+struct CheckMutex {
+  int iType;
+  sqlite3_mutex *mutex;
+};
+
+#define SQLITE_MUTEX_WARNONCONTENTION  (-1)
+
+/*
+** Pointer to real mutex methods object used by the CheckMutex
+** implementation. Set by checkMutexInit().
+*/
+static SQLITE_WSD const sqlite3_mutex_methods *pGlobalMutexMethods;
+
+#ifdef SQLITE_DEBUG
+static int checkMutexHeld(sqlite3_mutex *p){
+  return pGlobalMutexMethods->xMutexHeld(((CheckMutex*)p)->mutex);
+}
+static int checkMutexNotheld(sqlite3_mutex *p){
+  return pGlobalMutexMethods->xMutexNotheld(((CheckMutex*)p)->mutex);
+}
+#endif
+
+/*
+** Initialize and deinitialize the mutex subsystem.
+*/
+static int checkMutexInit(void){
+  pGlobalMutexMethods = sqlite3DefaultMutex();
+  return SQLITE_OK;
+}
+static int checkMutexEnd(void){
+  pGlobalMutexMethods = 0;
+  return SQLITE_OK;
+}
+
+/*
+** Allocate a mutex.
+*/
+static sqlite3_mutex *checkMutexAlloc(int iType){
+  static CheckMutex staticMutexes[] = {
+    {2, 0}, {3, 0}, {4, 0}, {5, 0},
+    {6, 0}, {7, 0}, {8, 0}, {9, 0},
+    {10, 0}, {11, 0}, {12, 0}, {13, 0}
+  };
+  CheckMutex *p = 0;
+
+  assert( SQLITE_MUTEX_RECURSIVE==1 && SQLITE_MUTEX_FAST==0 );
+  if( iType<2 ){
+    p = sqlite3MallocZero(sizeof(CheckMutex));
+    if( p==0 ) return 0;
+    p->iType = iType;
+  }else{
+#ifdef SQLITE_ENABLE_API_ARMOR
+    if( iType-2>=ArraySize(staticMutexes) ){
+      (void)SQLITE_MISUSE_BKPT;
+      return 0;
+    }
+#endif
+    p = &staticMutexes[iType-2];
+  }
+
+  if( p->mutex==0 ){
+    p->mutex = pGlobalMutexMethods->xMutexAlloc(iType);
+    if( p->mutex==0 ){
+      if( iType<2 ){
+        sqlite3_free(p);
+      }
+      p = 0;
+    }
+  }
+
+  return (sqlite3_mutex*)p;
+}
+
+/*
+** Free a mutex.
+*/
+static void checkMutexFree(sqlite3_mutex *p){
+  assert( SQLITE_MUTEX_RECURSIVE<2 );
+  assert( SQLITE_MUTEX_FAST<2 );
+  assert( SQLITE_MUTEX_WARNONCONTENTION<2 );
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ((CheckMutex*)p)->iType<2 )
+#endif
+  {
+    CheckMutex *pCheck = (CheckMutex*)p;
+    pGlobalMutexMethods->xMutexFree(pCheck->mutex);
+    sqlite3_free(pCheck);
+  }
+#ifdef SQLITE_ENABLE_API_ARMOR
+  else{
+    (void)SQLITE_MISUSE_BKPT;
+  }
+#endif
+}
+
+/*
+** Enter the mutex.
+*/
+static void checkMutexEnter(sqlite3_mutex *p){
+  CheckMutex *pCheck = (CheckMutex*)p;
+  if( pCheck->iType==SQLITE_MUTEX_WARNONCONTENTION ){
+    if( SQLITE_OK==pGlobalMutexMethods->xMutexTry(pCheck->mutex) ){
+      return;
+    }
+    sqlite3_log(SQLITE_MISUSE,
+        "illegal multi-threaded access to database connection"
+    );
+  }
+  pGlobalMutexMethods->xMutexEnter(pCheck->mutex);
+}
+
+/*
+** Enter the mutex (do not block).
+*/
+static int checkMutexTry(sqlite3_mutex *p){
+  CheckMutex *pCheck = (CheckMutex*)p;
+  return pGlobalMutexMethods->xMutexTry(pCheck->mutex);
+}
+
+/*
+** Leave the mutex.
+*/
+static void checkMutexLeave(sqlite3_mutex *p){
+  CheckMutex *pCheck = (CheckMutex*)p;
+  pGlobalMutexMethods->xMutexLeave(pCheck->mutex);
+}
+
+sqlite3_mutex_methods const *multiThreadedCheckMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    checkMutexInit,
+    checkMutexEnd,
+    checkMutexAlloc,
+    checkMutexFree,
+    checkMutexEnter,
+    checkMutexTry,
+    checkMutexLeave,
+#ifdef SQLITE_DEBUG
+    checkMutexHeld,
+    checkMutexNotheld
+#else
+    0,
+    0
+#endif
+  };
+  return &sMutex;
+}
+
+/*
+** Mark the SQLITE_MUTEX_RECURSIVE mutex passed as the only argument as
+** one on which there should be no contention.
+*/
+SQLITE_PRIVATE void sqlite3MutexWarnOnContention(sqlite3_mutex *p){
+  if( sqlite3GlobalConfig.mutex.xMutexAlloc==checkMutexAlloc ){
+    CheckMutex *pCheck = (CheckMutex*)p;
+    assert( pCheck->iType==SQLITE_MUTEX_RECURSIVE );
+    pCheck->iType = SQLITE_MUTEX_WARNONCONTENTION;
+  }
+}
+#endif   /* ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS */
+
+/*
+** Initialize the mutex system.
+*/
+SQLITE_PRIVATE int sqlite3MutexInit(void){
+  int rc = SQLITE_OK;
+  if( !sqlite3GlobalConfig.mutex.xMutexAlloc ){
+    /* If the xMutexAlloc method has not been set, then the user did not
+    ** install a mutex implementation via sqlite3_config() prior to
+    ** sqlite3_initialize() being called. This block copies pointers to
+    ** the default implementation into the sqlite3GlobalConfig structure.
+    */
+    sqlite3_mutex_methods const *pFrom;
+    sqlite3_mutex_methods *pTo = &sqlite3GlobalConfig.mutex;
+
+    if( sqlite3GlobalConfig.bCoreMutex ){
+#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
+      pFrom = multiThreadedCheckMutex();
+#else
+      pFrom = sqlite3DefaultMutex();
+#endif
+    }else{
+      pFrom = sqlite3NoopMutex();
+    }
+    pTo->xMutexInit = pFrom->xMutexInit;
+    pTo->xMutexEnd = pFrom->xMutexEnd;
+    pTo->xMutexFree = pFrom->xMutexFree;
+    pTo->xMutexEnter = pFrom->xMutexEnter;
+    pTo->xMutexTry = pFrom->xMutexTry;
+    pTo->xMutexLeave = pFrom->xMutexLeave;
+    pTo->xMutexHeld = pFrom->xMutexHeld;
+    pTo->xMutexNotheld = pFrom->xMutexNotheld;
+    sqlite3MemoryBarrier();
+    pTo->xMutexAlloc = pFrom->xMutexAlloc;
+  }
+  assert( sqlite3GlobalConfig.mutex.xMutexInit );
+  rc = sqlite3GlobalConfig.mutex.xMutexInit();
+
+#ifdef SQLITE_DEBUG
+  GLOBAL(int, mutexIsInit) = 1;
+#endif
+
+  sqlite3MemoryBarrier();
+  return rc;
+}
+
+/*
+** Shutdown the mutex system. This call frees resources allocated by
+** sqlite3MutexInit().
+*/
+SQLITE_PRIVATE int sqlite3MutexEnd(void){
+  int rc = SQLITE_OK;
+  if( sqlite3GlobalConfig.mutex.xMutexEnd ){
+    rc = sqlite3GlobalConfig.mutex.xMutexEnd();
+  }
+
+#ifdef SQLITE_DEBUG
+  GLOBAL(int, mutexIsInit) = 0;
+#endif
+
+  return rc;
+}
+
+/*
+** Retrieve a pointer to a static mutex or allocate a new dynamic one.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int id){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( id<=SQLITE_MUTEX_RECURSIVE && sqlite3_initialize() ) return 0;
+  if( id>SQLITE_MUTEX_RECURSIVE && sqlite3MutexInit() ) return 0;
+#endif
+  assert( sqlite3GlobalConfig.mutex.xMutexAlloc );
+  return sqlite3GlobalConfig.mutex.xMutexAlloc(id);
+}
+
+SQLITE_PRIVATE sqlite3_mutex *sqlite3MutexAlloc(int id){
+  if( !sqlite3GlobalConfig.bCoreMutex ){
+    return 0;
+  }
+  assert( GLOBAL(int, mutexIsInit) );
+  assert( sqlite3GlobalConfig.mutex.xMutexAlloc );
+  return sqlite3GlobalConfig.mutex.xMutexAlloc(id);
+}
+
+/*
+** Free a dynamic mutex.
+*/
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex *p){
+  if( p ){
+    assert( sqlite3GlobalConfig.mutex.xMutexFree );
+    sqlite3GlobalConfig.mutex.xMutexFree(p);
+  }
+}
+
+/*
+** Obtain the mutex p. If some other thread already has the mutex, block
+** until it can be obtained.
+*/
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex *p){
+  if( p ){
+    assert( sqlite3GlobalConfig.mutex.xMutexEnter );
+    sqlite3GlobalConfig.mutex.xMutexEnter(p);
+  }
+}
+
+/*
+** Obtain the mutex p. If successful, return SQLITE_OK. Otherwise, if another
+** thread holds the mutex and it cannot be obtained, return SQLITE_BUSY.
+*/
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex *p){
+  int rc = SQLITE_OK;
+  if( p ){
+    assert( sqlite3GlobalConfig.mutex.xMutexTry );
+    return sqlite3GlobalConfig.mutex.xMutexTry(p);
+  }
+  return rc;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was previously
+** entered by the same thread.  The behavior is undefined if the mutex
+** is not currently entered. If a NULL pointer is passed as an argument
+** this function is a no-op.
+*/
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex *p){
+  if( p ){
+    assert( sqlite3GlobalConfig.mutex.xMutexLeave );
+    sqlite3GlobalConfig.mutex.xMutexLeave(p);
+  }
+}
+
+#ifndef NDEBUG
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use inside assert() statements.
+**
+** Because these routines raise false-positive alerts in TSAN, disable
+** them (make them always return 1) when compiling with TSAN.
+*/
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex *p){
+# if defined(__has_feature)
+#   if __has_feature(thread_sanitizer)
+      p = 0;
+#   endif
+# endif
+  assert( p==0 || sqlite3GlobalConfig.mutex.xMutexHeld );
+  return p==0 || sqlite3GlobalConfig.mutex.xMutexHeld(p);
+}
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex *p){
+# if defined(__has_feature)
+#   if __has_feature(thread_sanitizer)
+      p = 0;
+#   endif
+# endif
+  assert( p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld );
+  return p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld(p);
+}
+#endif /* NDEBUG */
+
+#endif /* !defined(SQLITE_MUTEX_OMIT) */
+
+/************** End of mutex.c ***********************************************/
+/************** Begin file mutex_noop.c **************************************/
+/*
+** 2008 October 07
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes.
+**
+** This implementation in this file does not provide any mutual
+** exclusion and is thus suitable for use only in applications
+** that use SQLite in a single thread.  The routines defined
+** here are place-holders.  Applications can substitute working
+** mutex routines at start-time using the
+**
+**     sqlite3_config(SQLITE_CONFIG_MUTEX,...)
+**
+** interface.
+**
+** If compiled with SQLITE_DEBUG, then additional logic is inserted
+** that does error checking on mutexes to make sure they are being
+** called correctly.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_MUTEX_OMIT
+
+#ifndef SQLITE_DEBUG
+/*
+** Stub routines for all mutex methods.
+**
+** This routines provide no mutual exclusion or error checking.
+*/
+static int noopMutexInit(void){ return SQLITE_OK; }
+static int noopMutexEnd(void){ return SQLITE_OK; }
+static sqlite3_mutex *noopMutexAlloc(int id){
+  UNUSED_PARAMETER(id);
+  return (sqlite3_mutex*)8;
+}
+static void noopMutexFree(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
+static void noopMutexEnter(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
+static int noopMutexTry(sqlite3_mutex *p){
+  UNUSED_PARAMETER(p);
+  return SQLITE_OK;
+}
+static void noopMutexLeave(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
+
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3NoopMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    noopMutexInit,
+    noopMutexEnd,
+    noopMutexAlloc,
+    noopMutexFree,
+    noopMutexEnter,
+    noopMutexTry,
+    noopMutexLeave,
+
+    0,
+    0,
+  };
+
+  return &sMutex;
+}
+#endif /* !SQLITE_DEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+** In this implementation, error checking is provided for testing
+** and debugging purposes.  The mutexes still do not provide any
+** mutual exclusion.
+*/
+
+/*
+** The mutex object
+*/
+typedef struct sqlite3_debug_mutex {
+  int id;     /* The mutex type */
+  int cnt;    /* Number of entries without a matching leave */
+} sqlite3_debug_mutex;
+
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use inside assert() statements.
+*/
+static int debugMutexHeld(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  return p==0 || p->cnt>0;
+}
+static int debugMutexNotheld(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  return p==0 || p->cnt==0;
+}
+
+/*
+** Initialize and deinitialize the mutex subsystem.
+*/
+static int debugMutexInit(void){ return SQLITE_OK; }
+static int debugMutexEnd(void){ return SQLITE_OK; }
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated.
+*/
+static sqlite3_mutex *debugMutexAlloc(int id){
+  static sqlite3_debug_mutex aStatic[SQLITE_MUTEX_STATIC_VFS3 - 1];
+  sqlite3_debug_mutex *pNew = 0;
+  switch( id ){
+    case SQLITE_MUTEX_FAST:
+    case SQLITE_MUTEX_RECURSIVE: {
+      pNew = sqlite3Malloc(sizeof(*pNew));
+      if( pNew ){
+        pNew->id = id;
+        pNew->cnt = 0;
+      }
+      break;
+    }
+    default: {
+#ifdef SQLITE_ENABLE_API_ARMOR
+      if( id-2<0 || id-2>=ArraySize(aStatic) ){
+        (void)SQLITE_MISUSE_BKPT;
+        return 0;
+      }
+#endif
+      pNew = &aStatic[id-2];
+      pNew->id = id;
+      break;
+    }
+  }
+  return (sqlite3_mutex*)pNew;
+}
+
+/*
+** This routine deallocates a previously allocated mutex.
+*/
+static void debugMutexFree(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( p->cnt==0 );
+  if( p->id==SQLITE_MUTEX_RECURSIVE || p->id==SQLITE_MUTEX_FAST ){
+    sqlite3_free(p);
+  }else{
+#ifdef SQLITE_ENABLE_API_ARMOR
+    (void)SQLITE_MISUSE_BKPT;
+#endif
+  }
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+static void debugMutexEnter(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(pX) );
+  p->cnt++;
+}
+static int debugMutexTry(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(pX) );
+  p->cnt++;
+  return SQLITE_OK;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+static void debugMutexLeave(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( debugMutexHeld(pX) );
+  p->cnt--;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(pX) );
+}
+
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3NoopMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    debugMutexInit,
+    debugMutexEnd,
+    debugMutexAlloc,
+    debugMutexFree,
+    debugMutexEnter,
+    debugMutexTry,
+    debugMutexLeave,
+
+    debugMutexHeld,
+    debugMutexNotheld
+  };
+
+  return &sMutex;
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** If compiled with SQLITE_MUTEX_NOOP, then the no-op mutex implementation
+** is used regardless of the run-time threadsafety setting.
+*/
+#ifdef SQLITE_MUTEX_NOOP
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
+  return sqlite3NoopMutex();
+}
+#endif /* defined(SQLITE_MUTEX_NOOP) */
+#endif /* !defined(SQLITE_MUTEX_OMIT) */
+
+/************** End of mutex_noop.c ******************************************/
+/************** Begin file mutex_unix.c **************************************/
+/*
+** 2007 August 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes for pthreads
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** The code in this file is only used if we are compiling threadsafe
+** under unix with pthreads.
+**
+** Note that this implementation requires a version of pthreads that
+** supports recursive mutexes.
+*/
+#ifdef SQLITE_MUTEX_PTHREADS
+
+#include <pthread.h>
+
+/*
+** The sqlite3_mutex.id, sqlite3_mutex.nRef, and sqlite3_mutex.owner fields
+** are necessary under two conditions:  (1) Debug builds and (2) using
+** home-grown mutexes.  Encapsulate these conditions into a single #define.
+*/
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HOMEGROWN_RECURSIVE_MUTEX)
+# define SQLITE_MUTEX_NREF 1
+#else
+# define SQLITE_MUTEX_NREF 0
+#endif
+
+/*
+** Each recursive mutex is an instance of the following structure.
+*/
+struct sqlite3_mutex {
+  pthread_mutex_t mutex;     /* Mutex controlling the lock */
+#if SQLITE_MUTEX_NREF || defined(SQLITE_ENABLE_API_ARMOR)
+  int id;                    /* Mutex type */
+#endif
+#if SQLITE_MUTEX_NREF
+  volatile int nRef;         /* Number of entrances */
+  volatile pthread_t owner;  /* Thread that is within this mutex */
+  int trace;                 /* True to trace changes */
+#endif
+};
+#if SQLITE_MUTEX_NREF
+# define SQLITE3_MUTEX_INITIALIZER(id) \
+     {PTHREAD_MUTEX_INITIALIZER,id,0,(pthread_t)0,0}
+#elif defined(SQLITE_ENABLE_API_ARMOR)
+# define SQLITE3_MUTEX_INITIALIZER(id) { PTHREAD_MUTEX_INITIALIZER, id }
+#else
+#define SQLITE3_MUTEX_INITIALIZER(id) { PTHREAD_MUTEX_INITIALIZER }
+#endif
+
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use only inside assert() statements.  On some platforms,
+** there might be race conditions that can cause these routines to
+** deliver incorrect results.  In particular, if pthread_equal() is
+** not an atomic operation, then these routines might delivery
+** incorrect results.  On most platforms, pthread_equal() is a
+** comparison of two integers and is therefore atomic.  But we are
+** told that HPUX is not such a platform.  If so, then these routines
+** will not always work correctly on HPUX.
+**
+** On those platforms where pthread_equal() is not atomic, SQLite
+** should be compiled without -DSQLITE_DEBUG and with -DNDEBUG to
+** make sure no assert() statements are evaluated and hence these
+** routines are never called.
+*/
+#if !defined(NDEBUG) || defined(SQLITE_DEBUG)
+static int pthreadMutexHeld(sqlite3_mutex *p){
+  return (p->nRef!=0 && pthread_equal(p->owner, pthread_self()));
+}
+static int pthreadMutexNotheld(sqlite3_mutex *p){
+  return p->nRef==0 || pthread_equal(p->owner, pthread_self())==0;
+}
+#endif
+
+/*
+** Try to provide a memory barrier operation, needed for initialization
+** and also for the implementation of xShmBarrier in the VFS in cases
+** where SQLite is compiled without mutexes.
+*/
+SQLITE_PRIVATE void sqlite3MemoryBarrier(void){
+#if defined(SQLITE_MEMORY_BARRIER)
+  SQLITE_MEMORY_BARRIER;
+#elif defined(__GNUC__) && GCC_VERSION>=4001000
+  __sync_synchronize();
+#endif
+}
+
+/*
+** Initialize and deinitialize the mutex subsystem.
+*/
+static int pthreadMutexInit(void){ return SQLITE_OK; }
+static int pthreadMutexEnd(void){ return SQLITE_OK; }
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated.  SQLite
+** will unwind its stack and return an error.  The argument
+** to sqlite3_mutex_alloc() is one of these integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MAIN
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_OPEN
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
+** <li>  SQLITE_MUTEX_STATIC_APP1
+** <li>  SQLITE_MUTEX_STATIC_APP2
+** <li>  SQLITE_MUTEX_STATIC_APP3
+** <li>  SQLITE_MUTEX_STATIC_VFS1
+** <li>  SQLITE_MUTEX_STATIC_VFS2
+** <li>  SQLITE_MUTEX_STATIC_VFS3
+** </ul>
+**
+** The first two constants cause sqlite3_mutex_alloc() to create
+** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  But SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** The other allowed parameters to sqlite3_mutex_alloc() each return
+** a pointer to a static preexisting mutex.  Six static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  But for the static
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+*/
+static sqlite3_mutex *pthreadMutexAlloc(int iType){
+  static sqlite3_mutex staticMutexes[] = {
+    SQLITE3_MUTEX_INITIALIZER(2),
+    SQLITE3_MUTEX_INITIALIZER(3),
+    SQLITE3_MUTEX_INITIALIZER(4),
+    SQLITE3_MUTEX_INITIALIZER(5),
+    SQLITE3_MUTEX_INITIALIZER(6),
+    SQLITE3_MUTEX_INITIALIZER(7),
+    SQLITE3_MUTEX_INITIALIZER(8),
+    SQLITE3_MUTEX_INITIALIZER(9),
+    SQLITE3_MUTEX_INITIALIZER(10),
+    SQLITE3_MUTEX_INITIALIZER(11),
+    SQLITE3_MUTEX_INITIALIZER(12),
+    SQLITE3_MUTEX_INITIALIZER(13)
+  };
+  sqlite3_mutex *p;
+  switch( iType ){
+    case SQLITE_MUTEX_RECURSIVE: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+        /* If recursive mutexes are not available, we will have to
+        ** build our own.  See below. */
+        pthread_mutex_init(&p->mutex, 0);
+#else
+        /* Use a recursive mutex if it is available */
+        pthread_mutexattr_t recursiveAttr;
+        pthread_mutexattr_init(&recursiveAttr);
+        pthread_mutexattr_settype(&recursiveAttr, PTHREAD_MUTEX_RECURSIVE);
+        pthread_mutex_init(&p->mutex, &recursiveAttr);
+        pthread_mutexattr_destroy(&recursiveAttr);
+#endif
+#if SQLITE_MUTEX_NREF || defined(SQLITE_ENABLE_API_ARMOR)
+        p->id = SQLITE_MUTEX_RECURSIVE;
+#endif
+      }
+      break;
+    }
+    case SQLITE_MUTEX_FAST: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+        pthread_mutex_init(&p->mutex, 0);
+#if SQLITE_MUTEX_NREF || defined(SQLITE_ENABLE_API_ARMOR)
+        p->id = SQLITE_MUTEX_FAST;
+#endif
+      }
+      break;
+    }
+    default: {
+#ifdef SQLITE_ENABLE_API_ARMOR
+      if( iType-2<0 || iType-2>=ArraySize(staticMutexes) ){
+        (void)SQLITE_MISUSE_BKPT;
+        return 0;
+      }
+#endif
+      p = &staticMutexes[iType-2];
+      break;
+    }
+  }
+#if SQLITE_MUTEX_NREF || defined(SQLITE_ENABLE_API_ARMOR)
+  assert( p==0 || p->id==iType );
+#endif
+  return p;
+}
+
+
+/*
+** This routine deallocates a previously
+** allocated mutex.  SQLite is careful to deallocate every
+** mutex that it allocates.
+*/
+static void pthreadMutexFree(sqlite3_mutex *p){
+  assert( p->nRef==0 );
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE )
+#endif
+  {
+    pthread_mutex_destroy(&p->mutex);
+    sqlite3_free(p);
+  }
+#ifdef SQLITE_ENABLE_API_ARMOR
+  else{
+    (void)SQLITE_MISUSE_BKPT;
+  }
+#endif
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+static void pthreadMutexEnter(sqlite3_mutex *p){
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || pthreadMutexNotheld(p) );
+
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  /* If recursive mutexes are not available, then we have to grow
+  ** our own.  This implementation assumes that pthread_equal()
+  ** is atomic - that it cannot be deceived into thinking self
+  ** and p->owner are equal if p->owner changes between two values
+  ** that are not equal to self while the comparison is taking place.
+  ** This implementation also assumes a coherent cache - that
+  ** separate processes cannot read different values from the same
+  ** address at the same time.  If either of these two conditions
+  ** are not met, then the mutexes will fail and problems will result.
+  */
+  {
+    pthread_t self = pthread_self();
+    if( p->nRef>0 && pthread_equal(p->owner, self) ){
+      p->nRef++;
+    }else{
+      pthread_mutex_lock(&p->mutex);
+      assert( p->nRef==0 );
+      p->owner = self;
+      p->nRef = 1;
+    }
+  }
+#else
+  /* Use the built-in recursive mutexes if they are available.
+  */
+  pthread_mutex_lock(&p->mutex);
+#if SQLITE_MUTEX_NREF
+  assert( p->nRef>0 || p->owner==0 );
+  p->owner = pthread_self();
+  p->nRef++;
+#endif
+#endif
+
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
+}
+static int pthreadMutexTry(sqlite3_mutex *p){
+  int rc;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || pthreadMutexNotheld(p) );
+
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  /* If recursive mutexes are not available, then we have to grow
+  ** our own.  This implementation assumes that pthread_equal()
+  ** is atomic - that it cannot be deceived into thinking self
+  ** and p->owner are equal if p->owner changes between two values
+  ** that are not equal to self while the comparison is taking place.
+  ** This implementation also assumes a coherent cache - that
+  ** separate processes cannot read different values from the same
+  ** address at the same time.  If either of these two conditions
+  ** are not met, then the mutexes will fail and problems will result.
+  */
+  {
+    pthread_t self = pthread_self();
+    if( p->nRef>0 && pthread_equal(p->owner, self) ){
+      p->nRef++;
+      rc = SQLITE_OK;
+    }else if( pthread_mutex_trylock(&p->mutex)==0 ){
+      assert( p->nRef==0 );
+      p->owner = self;
+      p->nRef = 1;
+      rc = SQLITE_OK;
+    }else{
+      rc = SQLITE_BUSY;
+    }
+  }
+#else
+  /* Use the built-in recursive mutexes if they are available.
+  */
+  if( pthread_mutex_trylock(&p->mutex)==0 ){
+#if SQLITE_MUTEX_NREF
+    p->owner = pthread_self();
+    p->nRef++;
+#endif
+    rc = SQLITE_OK;
+  }else{
+    rc = SQLITE_BUSY;
+  }
+#endif
+
+#ifdef SQLITE_DEBUG
+  if( rc==SQLITE_OK && p->trace ){
+    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
+  return rc;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+static void pthreadMutexLeave(sqlite3_mutex *p){
+  assert( pthreadMutexHeld(p) );
+#if SQLITE_MUTEX_NREF
+  p->nRef--;
+  if( p->nRef==0 ) p->owner = 0;
+#endif
+  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
+
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  if( p->nRef==0 ){
+    pthread_mutex_unlock(&p->mutex);
+  }
+#else
+  pthread_mutex_unlock(&p->mutex);
+#endif
+
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
+}
+
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    pthreadMutexInit,
+    pthreadMutexEnd,
+    pthreadMutexAlloc,
+    pthreadMutexFree,
+    pthreadMutexEnter,
+    pthreadMutexTry,
+    pthreadMutexLeave,
+#ifdef SQLITE_DEBUG
+    pthreadMutexHeld,
+    pthreadMutexNotheld
+#else
+    0,
+    0
+#endif
+  };
+
+  return &sMutex;
+}
+
+#endif /* SQLITE_MUTEX_PTHREADS */
+
+/************** End of mutex_unix.c ******************************************/
+/************** Begin file mutex_w32.c ***************************************/
+/*
+** 2007 August 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes for Win32.
+*/
+/* #include "sqliteInt.h" */
+
+#if SQLITE_OS_WIN
+/*
+** Include code that is common to all os_*.c files
+*/
+/* #include "os_common.h" */
+
+/*
+** Include the header file for the Windows VFS.
+*/
+/************** Include os_win.h in the middle of mutex_w32.c ****************/
+/************** Begin file os_win.h ******************************************/
+/*
+** 2013 November 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to Windows.
+*/
+#ifndef SQLITE_OS_WIN_H
+#define SQLITE_OS_WIN_H
+
+/*
+** Include the primary Windows SDK header file.
+*/
+#include "windows.h"
+
+#ifdef __CYGWIN__
+# include <sys/cygwin.h>
+# include <errno.h> /* amalgamator: dontcache */
+#endif
+
+/*
+** Determine if we are dealing with Windows NT.
+**
+** We ought to be able to determine if we are compiling for Windows 9x or
+** Windows NT using the _WIN32_WINNT macro as follows:
+**
+** #if defined(_WIN32_WINNT)
+** # define SQLITE_OS_WINNT 1
+** #else
+** # define SQLITE_OS_WINNT 0
+** #endif
+**
+** However, Visual Studio 2005 does not set _WIN32_WINNT by default, as
+** it ought to, so the above test does not work.  We'll just assume that
+** everything is Windows NT unless the programmer explicitly says otherwise
+** by setting SQLITE_OS_WINNT to 0.
+*/
+#if SQLITE_OS_WIN && !defined(SQLITE_OS_WINNT)
+# define SQLITE_OS_WINNT 1
+#endif
+
+/*
+** Determine if we are dealing with Windows CE - which has a much reduced
+** API.
+*/
+#if defined(_WIN32_WCE)
+# define SQLITE_OS_WINCE 1
+#else
+# define SQLITE_OS_WINCE 0
+#endif
+
+/*
+** Determine if we are dealing with WinRT, which provides only a subset of
+** the full Win32 API.
+*/
+#if !defined(SQLITE_OS_WINRT)
+# define SQLITE_OS_WINRT 0
+#endif
+
+/*
+** For WinCE, some API function parameters do not appear to be declared as
+** volatile.
+*/
+#if SQLITE_OS_WINCE
+# define SQLITE_WIN32_VOLATILE
+#else
+# define SQLITE_WIN32_VOLATILE volatile
+#endif
+
+/*
+** For some Windows sub-platforms, the _beginthreadex() / _endthreadex()
+** functions are not available (e.g. those not using MSVC, Cygwin, etc).
+*/
+#if SQLITE_OS_WIN && !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && \
+    SQLITE_THREADSAFE>0 && !defined(__CYGWIN__)
+# define SQLITE_OS_WIN_THREADS 1
+#else
+# define SQLITE_OS_WIN_THREADS 0
+#endif
+
+#endif /* SQLITE_OS_WIN_H */
+
+/************** End of os_win.h **********************************************/
+/************** Continuing where we left off in mutex_w32.c ******************/
+#endif
+
+/*
+** The code in this file is only used if we are compiling multithreaded
+** on a Win32 system.
+*/
+#ifdef SQLITE_MUTEX_W32
+
+/*
+** Each recursive mutex is an instance of the following structure.
+*/
+struct sqlite3_mutex {
+  CRITICAL_SECTION mutex;    /* Mutex controlling the lock */
+  int id;                    /* Mutex type */
+#ifdef SQLITE_DEBUG
+  volatile int nRef;         /* Number of entrances */
+  volatile DWORD owner;      /* Thread holding this mutex */
+  volatile LONG trace;       /* True to trace changes */
+#endif
+};
+
+/*
+** These are the initializer values used when declaring a "static" mutex
+** on Win32.  It should be noted that all mutexes require initialization
+** on the Win32 platform.
+*/
+#define SQLITE_W32_MUTEX_INITIALIZER { 0 }
+
+#ifdef SQLITE_DEBUG
+#define SQLITE3_MUTEX_INITIALIZER(id) { SQLITE_W32_MUTEX_INITIALIZER, id, \
+                                    0L, (DWORD)0, 0 }
+#else
+#define SQLITE3_MUTEX_INITIALIZER(id) { SQLITE_W32_MUTEX_INITIALIZER, id }
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use only inside assert() statements.
+*/
+static int winMutexHeld(sqlite3_mutex *p){
+  return p->nRef!=0 && p->owner==GetCurrentThreadId();
+}
+
+static int winMutexNotheld2(sqlite3_mutex *p, DWORD tid){
+  return p->nRef==0 || p->owner!=tid;
+}
+
+static int winMutexNotheld(sqlite3_mutex *p){
+  DWORD tid = GetCurrentThreadId();
+  return winMutexNotheld2(p, tid);
+}
+#endif
+
+/*
+** Try to provide a memory barrier operation, needed for initialization
+** and also for the xShmBarrier method of the VFS in cases when SQLite is
+** compiled without mutexes (SQLITE_THREADSAFE=0).
+*/
+SQLITE_PRIVATE void sqlite3MemoryBarrier(void){
+#if defined(SQLITE_MEMORY_BARRIER)
+  SQLITE_MEMORY_BARRIER;
+#elif defined(__GNUC__)
+  __sync_synchronize();
+#elif MSVC_VERSION>=1400
+  _ReadWriteBarrier();
+#elif defined(MemoryBarrier)
+  MemoryBarrier();
+#endif
+}
+
+/*
+** Initialize and deinitialize the mutex subsystem.
+*/
+static sqlite3_mutex winMutex_staticMutexes[] = {
+  SQLITE3_MUTEX_INITIALIZER(2),
+  SQLITE3_MUTEX_INITIALIZER(3),
+  SQLITE3_MUTEX_INITIALIZER(4),
+  SQLITE3_MUTEX_INITIALIZER(5),
+  SQLITE3_MUTEX_INITIALIZER(6),
+  SQLITE3_MUTEX_INITIALIZER(7),
+  SQLITE3_MUTEX_INITIALIZER(8),
+  SQLITE3_MUTEX_INITIALIZER(9),
+  SQLITE3_MUTEX_INITIALIZER(10),
+  SQLITE3_MUTEX_INITIALIZER(11),
+  SQLITE3_MUTEX_INITIALIZER(12),
+  SQLITE3_MUTEX_INITIALIZER(13)
+};
+
+static int winMutex_isInit = 0;
+static int winMutex_isNt = -1; /* <0 means "need to query" */
+
+/* As the winMutexInit() and winMutexEnd() functions are called as part
+** of the sqlite3_initialize() and sqlite3_shutdown() processing, the
+** "interlocked" magic used here is probably not strictly necessary.
+*/
+static LONG SQLITE_WIN32_VOLATILE winMutex_lock = 0;
+
+SQLITE_API int sqlite3_win32_is_nt(void); /* os_win.c */
+SQLITE_API void sqlite3_win32_sleep(DWORD milliseconds); /* os_win.c */
+
+static int winMutexInit(void){
+  /* The first to increment to 1 does actual initialization */
+  if( InterlockedCompareExchange(&winMutex_lock, 1, 0)==0 ){
+    int i;
+    for(i=0; i<ArraySize(winMutex_staticMutexes); i++){
+#if SQLITE_OS_WINRT
+      InitializeCriticalSectionEx(&winMutex_staticMutexes[i].mutex, 0, 0);
+#else
+      InitializeCriticalSection(&winMutex_staticMutexes[i].mutex);
+#endif
+    }
+    winMutex_isInit = 1;
+  }else{
+    /* Another thread is (in the process of) initializing the static
+    ** mutexes */
+    while( !winMutex_isInit ){
+      sqlite3_win32_sleep(1);
+    }
+  }
+  return SQLITE_OK;
+}
+
+static int winMutexEnd(void){
+  /* The first to decrement to 0 does actual shutdown
+  ** (which should be the last to shutdown.) */
+  if( InterlockedCompareExchange(&winMutex_lock, 0, 1)==1 ){
+    if( winMutex_isInit==1 ){
+      int i;
+      for(i=0; i<ArraySize(winMutex_staticMutexes); i++){
+        DeleteCriticalSection(&winMutex_staticMutexes[i].mutex);
+      }
+      winMutex_isInit = 0;
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated.  SQLite
+** will unwind its stack and return an error.  The argument
+** to sqlite3_mutex_alloc() is one of these integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MAIN
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_OPEN
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
+** <li>  SQLITE_MUTEX_STATIC_APP1
+** <li>  SQLITE_MUTEX_STATIC_APP2
+** <li>  SQLITE_MUTEX_STATIC_APP3
+** <li>  SQLITE_MUTEX_STATIC_VFS1
+** <li>  SQLITE_MUTEX_STATIC_VFS2
+** <li>  SQLITE_MUTEX_STATIC_VFS3
+** </ul>
+**
+** The first two constants cause sqlite3_mutex_alloc() to create
+** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  But SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** The other allowed parameters to sqlite3_mutex_alloc() each return
+** a pointer to a static preexisting mutex.  Six static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  But for the static
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+*/
+static sqlite3_mutex *winMutexAlloc(int iType){
+  sqlite3_mutex *p;
+
+  switch( iType ){
+    case SQLITE_MUTEX_FAST:
+    case SQLITE_MUTEX_RECURSIVE: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+        p->id = iType;
+#ifdef SQLITE_DEBUG
+#ifdef SQLITE_WIN32_MUTEX_TRACE_DYNAMIC
+        p->trace = 1;
+#endif
+#endif
+#if SQLITE_OS_WINRT
+        InitializeCriticalSectionEx(&p->mutex, 0, 0);
+#else
+        InitializeCriticalSection(&p->mutex);
+#endif
+      }
+      break;
+    }
+    default: {
+#ifdef SQLITE_ENABLE_API_ARMOR
+      if( iType-2<0 || iType-2>=ArraySize(winMutex_staticMutexes) ){
+        (void)SQLITE_MISUSE_BKPT;
+        return 0;
+      }
+#endif
+      p = &winMutex_staticMutexes[iType-2];
+#ifdef SQLITE_DEBUG
+#ifdef SQLITE_WIN32_MUTEX_TRACE_STATIC
+      InterlockedCompareExchange(&p->trace, 1, 0);
+#endif
+#endif
+      break;
+    }
+  }
+  assert( p==0 || p->id==iType );
+  return p;
+}
+
+
+/*
+** This routine deallocates a previously
+** allocated mutex.  SQLite is careful to deallocate every
+** mutex that it allocates.
+*/
+static void winMutexFree(sqlite3_mutex *p){
+  assert( p );
+  assert( p->nRef==0 && p->owner==0 );
+  if( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE ){
+    DeleteCriticalSection(&p->mutex);
+    sqlite3_free(p);
+  }else{
+#ifdef SQLITE_ENABLE_API_ARMOR
+    (void)SQLITE_MISUSE_BKPT;
+#endif
+  }
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+static void winMutexEnter(sqlite3_mutex *p){
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  DWORD tid = GetCurrentThreadId();
+#endif
+#ifdef SQLITE_DEBUG
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
+#else
+  assert( p );
+#endif
+  assert( winMutex_isInit==1 );
+  EnterCriticalSection(&p->mutex);
+#ifdef SQLITE_DEBUG
+  assert( p->nRef>0 || p->owner==0 );
+  p->owner = tid;
+  p->nRef++;
+  if( p->trace ){
+    OSTRACE(("ENTER-MUTEX tid=%lu, mutex(%d)=%p (%d), nRef=%d\n",
+             tid, p->id, p, p->trace, p->nRef));
+  }
+#endif
+}
+
+static int winMutexTry(sqlite3_mutex *p){
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  DWORD tid = GetCurrentThreadId();
+#endif
+  int rc = SQLITE_BUSY;
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
+  /*
+  ** The sqlite3_mutex_try() routine is very rarely used, and when it
+  ** is used it is merely an optimization.  So it is OK for it to always
+  ** fail.
+  **
+  ** The TryEnterCriticalSection() interface is only available on WinNT.
+  ** And some windows compilers complain if you try to use it without
+  ** first doing some #defines that prevent SQLite from building on Win98.
+  ** For that reason, we will omit this optimization for now.  See
+  ** ticket #2685.
+  */
+#if defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x0400
+  assert( winMutex_isInit==1 );
+  assert( winMutex_isNt>=-1 && winMutex_isNt<=1 );
+  if( winMutex_isNt<0 ){
+    winMutex_isNt = sqlite3_win32_is_nt();
+  }
+  assert( winMutex_isNt==0 || winMutex_isNt==1 );
+  if( winMutex_isNt && TryEnterCriticalSection(&p->mutex) ){
+#ifdef SQLITE_DEBUG
+    p->owner = tid;
+    p->nRef++;
+#endif
+    rc = SQLITE_OK;
+  }
+#else
+  UNUSED_PARAMETER(p);
+#endif
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    OSTRACE(("TRY-MUTEX tid=%lu, mutex(%d)=%p (%d), owner=%lu, nRef=%d, rc=%s\n",
+             tid, p->id, p, p->trace, p->owner, p->nRef, sqlite3ErrName(rc)));
+  }
+#endif
+  return rc;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+static void winMutexLeave(sqlite3_mutex *p){
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  DWORD tid = GetCurrentThreadId();
+#endif
+  assert( p );
+#ifdef SQLITE_DEBUG
+  assert( p->nRef>0 );
+  assert( p->owner==tid );
+  p->nRef--;
+  if( p->nRef==0 ) p->owner = 0;
+  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
+#endif
+  assert( winMutex_isInit==1 );
+  LeaveCriticalSection(&p->mutex);
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    OSTRACE(("LEAVE-MUTEX tid=%lu, mutex(%d)=%p (%d), nRef=%d\n",
+             tid, p->id, p, p->trace, p->nRef));
+  }
+#endif
+}
+
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    winMutexInit,
+    winMutexEnd,
+    winMutexAlloc,
+    winMutexFree,
+    winMutexEnter,
+    winMutexTry,
+    winMutexLeave,
+#ifdef SQLITE_DEBUG
+    winMutexHeld,
+    winMutexNotheld
+#else
+    0,
+    0
+#endif
+  };
+  return &sMutex;
+}
+
+#endif /* SQLITE_MUTEX_W32 */
+
+/************** End of mutex_w32.c *******************************************/
+/************** Begin file malloc.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** Memory allocation functions used throughout sqlite.
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdarg.h> */
+
+/*
+** Attempt to release up to n bytes of non-essential memory currently
+** held by SQLite. An example of non-essential memory is memory used to
+** cache database pages that are not currently in use.
+*/
+SQLITE_API int sqlite3_release_memory(int n){
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  return sqlite3PcacheReleaseMemory(n);
+#else
+  /* IMPLEMENTATION-OF: R-34391-24921 The sqlite3_release_memory() routine
+  ** is a no-op returning zero if SQLite is not compiled with
+  ** SQLITE_ENABLE_MEMORY_MANAGEMENT. */
+  UNUSED_PARAMETER(n);
+  return 0;
+#endif
+}
+
+/*
+** Default value of the hard heap limit.  0 means "no limit".
+*/
+#ifndef SQLITE_MAX_MEMORY
+# define SQLITE_MAX_MEMORY 0
+#endif
+
+/*
+** State information local to the memory allocation subsystem.
+*/
+static SQLITE_WSD struct Mem0Global {
+  sqlite3_mutex *mutex;         /* Mutex to serialize access */
+  sqlite3_int64 alarmThreshold; /* The soft heap limit */
+  sqlite3_int64 hardLimit;      /* The hard upper bound on memory */
+
+  /*
+  ** True if heap is nearly "full" where "full" is defined by the
+  ** sqlite3_soft_heap_limit() setting.
+  */
+  int nearlyFull;
+} mem0 = { 0, SQLITE_MAX_MEMORY, SQLITE_MAX_MEMORY, 0 };
+
+#define mem0 GLOBAL(struct Mem0Global, mem0)
+
+/*
+** Return the memory allocator mutex. sqlite3_status() needs it.
+*/
+SQLITE_PRIVATE sqlite3_mutex *sqlite3MallocMutex(void){
+  return mem0.mutex;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Deprecated external interface.  It used to set an alarm callback
+** that was invoked when memory usage grew too large.  Now it is a
+** no-op.
+*/
+SQLITE_API int sqlite3_memory_alarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  (void)xCallback;
+  (void)pArg;
+  (void)iThreshold;
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Set the soft heap-size limit for the library.  An argument of
+** zero disables the limit.  A negative argument is a no-op used to
+** obtain the return value.
+**
+** The return value is the value of the heap limit just before this
+** interface was called.
+**
+** If the hard heap limit is enabled, then the soft heap limit cannot
+** be disabled nor raised above the hard heap limit.
+*/
+SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){
+  sqlite3_int64 priorLimit;
+  sqlite3_int64 excess;
+  sqlite3_int64 nUsed;
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return -1;
+#endif
+  sqlite3_mutex_enter(mem0.mutex);
+  priorLimit = mem0.alarmThreshold;
+  if( n<0 ){
+    sqlite3_mutex_leave(mem0.mutex);
+    return priorLimit;
+  }
+  if( mem0.hardLimit>0 && (n>mem0.hardLimit || n==0) ){
+    n = mem0.hardLimit;
+  }
+  mem0.alarmThreshold = n;
+  nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
+  AtomicStore(&mem0.nearlyFull, n>0 && n<=nUsed);
+  sqlite3_mutex_leave(mem0.mutex);
+  excess = sqlite3_memory_used() - n;
+  if( excess>0 ) sqlite3_release_memory((int)(excess & 0x7fffffff));
+  return priorLimit;
+}
+SQLITE_API void sqlite3_soft_heap_limit(int n){
+  if( n<0 ) n = 0;
+  sqlite3_soft_heap_limit64(n);
+}
+
+/*
+** Set the hard heap-size limit for the library. An argument of zero
+** disables the hard heap limit.  A negative argument is a no-op used
+** to obtain the return value without affecting the hard heap limit.
+**
+** The return value is the value of the hard heap limit just prior to
+** calling this interface.
+**
+** Setting the hard heap limit will also activate the soft heap limit
+** and constrain the soft heap limit to be no more than the hard heap
+** limit.
+*/
+SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 n){
+  sqlite3_int64 priorLimit;
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return -1;
+#endif
+  sqlite3_mutex_enter(mem0.mutex);
+  priorLimit = mem0.hardLimit;
+  if( n>=0 ){
+    mem0.hardLimit = n;
+    if( n<mem0.alarmThreshold || mem0.alarmThreshold==0 ){
+      mem0.alarmThreshold = n;
+    }
+  }
+  sqlite3_mutex_leave(mem0.mutex);
+  return priorLimit;
+}
+
+
+/*
+** Initialize the memory allocation subsystem.
+*/
+SQLITE_PRIVATE int sqlite3MallocInit(void){
+  int rc;
+  if( sqlite3GlobalConfig.m.xMalloc==0 ){
+    sqlite3MemSetDefault();
+  }
+  mem0.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  if( sqlite3GlobalConfig.pPage==0 || sqlite3GlobalConfig.szPage<512
+      || sqlite3GlobalConfig.nPage<=0 ){
+    sqlite3GlobalConfig.pPage = 0;
+    sqlite3GlobalConfig.szPage = 0;
+  }
+  rc = sqlite3GlobalConfig.m.xInit(sqlite3GlobalConfig.m.pAppData);
+  if( rc!=SQLITE_OK ) memset(&mem0, 0, sizeof(mem0));
+  return rc;
+}
+
+/*
+** Return true if the heap is currently under memory pressure - in other
+** words if the amount of heap used is close to the limit set by
+** sqlite3_soft_heap_limit().
+*/
+SQLITE_PRIVATE int sqlite3HeapNearlyFull(void){
+  return AtomicLoad(&mem0.nearlyFull);
+}
+
+/*
+** Deinitialize the memory allocation subsystem.
+*/
+SQLITE_PRIVATE void sqlite3MallocEnd(void){
+  if( sqlite3GlobalConfig.m.xShutdown ){
+    sqlite3GlobalConfig.m.xShutdown(sqlite3GlobalConfig.m.pAppData);
+  }
+  memset(&mem0, 0, sizeof(mem0));
+}
+
+/*
+** Return the amount of memory currently checked out.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void){
+  sqlite3_int64 res, mx;
+  sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &res, &mx, 0);
+  return res;
+}
+
+/*
+** Return the maximum amount of memory that has ever been
+** checked out since either the beginning of this process
+** or since the most recent reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
+  sqlite3_int64 res, mx;
+  sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &res, &mx, resetFlag);
+  return mx;
+}
+
+/*
+** Trigger the alarm
+*/
+static void sqlite3MallocAlarm(int nByte){
+  if( mem0.alarmThreshold<=0 ) return;
+  sqlite3_mutex_leave(mem0.mutex);
+  sqlite3_release_memory(nByte);
+  sqlite3_mutex_enter(mem0.mutex);
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** This routine is called whenever an out-of-memory condition is seen,
+** It's only purpose to to serve as a breakpoint for gdb or similar
+** code debuggers when working on out-of-memory conditions, for example
+** caused by PRAGMA hard_heap_limit=N.
+*/
+static SQLITE_NOINLINE void test_oom_breakpoint(u64 n){
+  static u64 nOomFault = 0;
+  nOomFault += n;
+  /* The assert() is never reached in a human lifetime.  It  is here mostly
+  ** to prevent code optimizers from optimizing out this function. */
+  assert( (nOomFault>>32) < 0xffffffff );
+}
+#else
+# define test_oom_breakpoint(X)   /* No-op for production builds */
+#endif
+
+/*
+** Do a memory allocation with statistics and alarms.  Assume the
+** lock is already held.
+*/
+static void mallocWithAlarm(int n, void **pp){
+  void *p;
+  int nFull;
+  assert( sqlite3_mutex_held(mem0.mutex) );
+  assert( n>0 );
+
+  /* In Firefox (circa 2017-02-08), xRoundup() is remapped to an internal
+  ** implementation of malloc_good_size(), which must be called in debug
+  ** mode and specifically when the DMD "Dark Matter Detector" is enabled
+  ** or else a crash results.  Hence, do not attempt to optimize out the
+  ** following xRoundup() call. */
+  nFull = sqlite3GlobalConfig.m.xRoundup(n);
+
+  sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, n);
+  if( mem0.alarmThreshold>0 ){
+    sqlite3_int64 nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
+    if( nUsed >= mem0.alarmThreshold - nFull ){
+      AtomicStore(&mem0.nearlyFull, 1);
+      sqlite3MallocAlarm(nFull);
+      if( mem0.hardLimit ){
+        nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
+        if( nUsed >= mem0.hardLimit - nFull ){
+          test_oom_breakpoint(1);
+          *pp = 0;
+          return;
+        }
+      }
+    }else{
+      AtomicStore(&mem0.nearlyFull, 0);
+    }
+  }
+  p = sqlite3GlobalConfig.m.xMalloc(nFull);
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  if( p==0 && mem0.alarmThreshold>0 ){
+    sqlite3MallocAlarm(nFull);
+    p = sqlite3GlobalConfig.m.xMalloc(nFull);
+  }
+#endif
+  if( p ){
+    nFull = sqlite3MallocSize(p);
+    sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nFull);
+    sqlite3StatusUp(SQLITE_STATUS_MALLOC_COUNT, 1);
+  }
+  *pp = p;
+}
+
+/*
+** Maximum size of any single memory allocation.
+**
+** This is not a limit on the total amount of memory used.  This is
+** a limit on the size parameter to sqlite3_malloc() and sqlite3_realloc().
+**
+** The upper bound is slightly less than 2GiB:  0x7ffffeff == 2,147,483,391
+** This provides a 256-byte safety margin for defense against 32-bit
+** signed integer overflow bugs when computing memory allocation sizes.
+** Paranoid applications might want to reduce the maximum allocation size
+** further for an even larger safety margin.  0x3fffffff or 0x0fffffff
+** or even smaller would be reasonable upper bounds on the size of a memory
+** allocations for most applications.
+*/
+#ifndef SQLITE_MAX_ALLOCATION_SIZE
+# define SQLITE_MAX_ALLOCATION_SIZE  2147483391
+#endif
+#if SQLITE_MAX_ALLOCATION_SIZE>2147483391
+# error Maximum size for SQLITE_MAX_ALLOCATION_SIZE is 2147483391
+#endif
+
+/*
+** Allocate memory.  This routine is like sqlite3_malloc() except that it
+** assumes the memory subsystem has already been initialized.
+*/
+SQLITE_PRIVATE void *sqlite3Malloc(u64 n){
+  void *p;
+  if( n==0 || n>SQLITE_MAX_ALLOCATION_SIZE ){
+    p = 0;
+  }else if( sqlite3GlobalConfig.bMemstat ){
+    sqlite3_mutex_enter(mem0.mutex);
+    mallocWithAlarm((int)n, &p);
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    p = sqlite3GlobalConfig.m.xMalloc((int)n);
+  }
+  assert( EIGHT_BYTE_ALIGNMENT(p) );  /* IMP: R-11148-40995 */
+  return p;
+}
+
+/*
+** This version of the memory allocation is for use by the application.
+** First make sure the memory subsystem is initialized, then do the
+** allocation.
+*/
+SQLITE_API void *sqlite3_malloc(int n){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return n<=0 ? 0 : sqlite3Malloc(n);
+}
+SQLITE_API void *sqlite3_malloc64(sqlite3_uint64 n){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return sqlite3Malloc(n);
+}
+
+/*
+** TRUE if p is a lookaside memory allocation from db
+*/
+#ifndef SQLITE_OMIT_LOOKASIDE
+static int isLookaside(sqlite3 *db, const void *p){
+  return SQLITE_WITHIN(p, db->lookaside.pStart, db->lookaside.pTrueEnd);
+}
+#else
+#define isLookaside(A,B) 0
+#endif
+
+/*
+** Return the size of a memory allocation previously obtained from
+** sqlite3Malloc() or sqlite3_malloc().
+*/
+SQLITE_PRIVATE int sqlite3MallocSize(const void *p){
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  return sqlite3GlobalConfig.m.xSize((void*)p);
+}
+static int lookasideMallocSize(sqlite3 *db, const void *p){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  return p<db->lookaside.pMiddle ? db->lookaside.szTrue : LOOKASIDE_SMALL;
+#else
+  return db->lookaside.szTrue;
+#endif
+}
+SQLITE_PRIVATE int sqlite3DbMallocSize(sqlite3 *db, const void *p){
+  assert( p!=0 );
+#ifdef SQLITE_DEBUG
+  if( db==0 ){
+    assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  }else if( !isLookaside(db,p) ){
+    assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+    assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  }
+#endif
+  if( db ){
+    if( ((uptr)p)<(uptr)(db->lookaside.pTrueEnd) ){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+      if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
+        assert( sqlite3_mutex_held(db->mutex) );
+        return LOOKASIDE_SMALL;
+      }
+#endif
+      if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
+        assert( sqlite3_mutex_held(db->mutex) );
+        return db->lookaside.szTrue;
+      }
+    }
+  }
+  return sqlite3GlobalConfig.m.xSize((void*)p);
+}
+SQLITE_API sqlite3_uint64 sqlite3_msize(void *p){
+  assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  return p ? sqlite3GlobalConfig.m.xSize(p) : 0;
+}
+
+/*
+** Free memory previously obtained from sqlite3Malloc().
+*/
+SQLITE_API void sqlite3_free(void *p){
+  if( p==0 ) return;  /* IMP: R-49053-54554 */
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
+  if( sqlite3GlobalConfig.bMemstat ){
+    sqlite3_mutex_enter(mem0.mutex);
+    sqlite3StatusDown(SQLITE_STATUS_MEMORY_USED, sqlite3MallocSize(p));
+    sqlite3StatusDown(SQLITE_STATUS_MALLOC_COUNT, 1);
+    sqlite3GlobalConfig.m.xFree(p);
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    sqlite3GlobalConfig.m.xFree(p);
+  }
+}
+
+/*
+** Add the size of memory allocation "p" to the count in
+** *db->pnBytesFreed.
+*/
+static SQLITE_NOINLINE void measureAllocationSize(sqlite3 *db, void *p){
+  *db->pnBytesFreed += sqlite3DbMallocSize(db,p);
+}
+
+/*
+** Free memory that might be associated with a particular database
+** connection.  Calling sqlite3DbFree(D,X) for X==0 is a harmless no-op.
+** The sqlite3DbFreeNN(D,X) version requires that X be non-NULL.
+*/
+SQLITE_PRIVATE void sqlite3DbFreeNN(sqlite3 *db, void *p){
+  assert( db==0 || sqlite3_mutex_held(db->mutex) );
+  assert( p!=0 );
+  if( db ){
+    if( ((uptr)p)<(uptr)(db->lookaside.pEnd) ){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+      if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
+        LookasideSlot *pBuf = (LookasideSlot*)p;
+        assert( db->pnBytesFreed==0 );
+#ifdef SQLITE_DEBUG
+        memset(p, 0xaa, LOOKASIDE_SMALL);  /* Trash freed content */
+#endif
+        pBuf->pNext = db->lookaside.pSmallFree;
+        db->lookaside.pSmallFree = pBuf;
+        return;
+      }
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+      if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
+        LookasideSlot *pBuf = (LookasideSlot*)p;
+        assert( db->pnBytesFreed==0 );
+#ifdef SQLITE_DEBUG
+        memset(p, 0xaa, db->lookaside.szTrue);  /* Trash freed content */
+#endif
+        pBuf->pNext = db->lookaside.pFree;
+        db->lookaside.pFree = pBuf;
+        return;
+      }
+    }
+    if( db->pnBytesFreed ){
+      measureAllocationSize(db, p);
+      return;
+    }
+  }
+  assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
+  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+  sqlite3_free(p);
+}
+SQLITE_PRIVATE void sqlite3DbNNFreeNN(sqlite3 *db, void *p){
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( p!=0 );
+  if( ((uptr)p)<(uptr)(db->lookaside.pEnd) ){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+    if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
+      LookasideSlot *pBuf = (LookasideSlot*)p;
+      assert( db->pnBytesFreed==0 );
+#ifdef SQLITE_DEBUG
+      memset(p, 0xaa, LOOKASIDE_SMALL);  /* Trash freed content */
+#endif
+      pBuf->pNext = db->lookaside.pSmallFree;
+      db->lookaside.pSmallFree = pBuf;
+      return;
+    }
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+    if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
+      LookasideSlot *pBuf = (LookasideSlot*)p;
+      assert( db->pnBytesFreed==0 );
+#ifdef SQLITE_DEBUG
+      memset(p, 0xaa, db->lookaside.szTrue);  /* Trash freed content */
+#endif
+      pBuf->pNext = db->lookaside.pFree;
+      db->lookaside.pFree = pBuf;
+      return;
+    }
+  }
+  if( db->pnBytesFreed ){
+    measureAllocationSize(db, p);
+    return;
+  }
+  assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+  sqlite3_free(p);
+}
+SQLITE_PRIVATE void sqlite3DbFree(sqlite3 *db, void *p){
+  assert( db==0 || sqlite3_mutex_held(db->mutex) );
+  if( p ) sqlite3DbFreeNN(db, p);
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+SQLITE_PRIVATE void *sqlite3Realloc(void *pOld, u64 nBytes){
+  int nOld, nNew, nDiff;
+  void *pNew;
+  assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugNoType(pOld, (u8)~MEMTYPE_HEAP) );
+  if( pOld==0 ){
+    return sqlite3Malloc(nBytes); /* IMP: R-04300-56712 */
+  }
+  if( nBytes==0 ){
+    sqlite3_free(pOld); /* IMP: R-26507-47431 */
+    return 0;
+  }
+  if( nBytes>=0x7fffff00 ){
+    /* The 0x7ffff00 limit term is explained in comments on sqlite3Malloc() */
+    return 0;
+  }
+  nOld = sqlite3MallocSize(pOld);
+  /* IMPLEMENTATION-OF: R-46199-30249 SQLite guarantees that the second
+  ** argument to xRealloc is always a value returned by a prior call to
+  ** xRoundup. */
+  nNew = sqlite3GlobalConfig.m.xRoundup((int)nBytes);
+  if( nOld==nNew ){
+    pNew = pOld;
+  }else if( sqlite3GlobalConfig.bMemstat ){
+    sqlite3_int64 nUsed;
+    sqlite3_mutex_enter(mem0.mutex);
+    sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, (int)nBytes);
+    nDiff = nNew - nOld;
+    if( nDiff>0 && (nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED)) >=
+          mem0.alarmThreshold-nDiff ){
+      sqlite3MallocAlarm(nDiff);
+      if( mem0.hardLimit>0 && nUsed >= mem0.hardLimit - nDiff ){
+        sqlite3_mutex_leave(mem0.mutex);
+        test_oom_breakpoint(1);
+        return 0;
+      }
+    }
+    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+    if( pNew==0 && mem0.alarmThreshold>0 ){
+      sqlite3MallocAlarm((int)nBytes);
+      pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
+    }
+#endif
+    if( pNew ){
+      nNew = sqlite3MallocSize(pNew);
+      sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nNew-nOld);
+    }
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
+  }
+  assert( EIGHT_BYTE_ALIGNMENT(pNew) ); /* IMP: R-11148-40995 */
+  return pNew;
+}
+
+/*
+** The public interface to sqlite3Realloc.  Make sure that the memory
+** subsystem is initialized prior to invoking sqliteRealloc.
+*/
+SQLITE_API void *sqlite3_realloc(void *pOld, int n){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  if( n<0 ) n = 0;  /* IMP: R-26507-47431 */
+  return sqlite3Realloc(pOld, n);
+}
+SQLITE_API void *sqlite3_realloc64(void *pOld, sqlite3_uint64 n){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return sqlite3Realloc(pOld, n);
+}
+
+
+/*
+** Allocate and zero memory.
+*/
+SQLITE_PRIVATE void *sqlite3MallocZero(u64 n){
+  void *p = sqlite3Malloc(n);
+  if( p ){
+    memset(p, 0, (size_t)n);
+  }
+  return p;
+}
+
+/*
+** Allocate and zero memory.  If the allocation fails, make
+** the mallocFailed flag in the connection pointer.
+*/
+SQLITE_PRIVATE void *sqlite3DbMallocZero(sqlite3 *db, u64 n){
+  void *p;
+  testcase( db==0 );
+  p = sqlite3DbMallocRaw(db, n);
+  if( p ) memset(p, 0, (size_t)n);
+  return p;
+}
+
+
+/* Finish the work of sqlite3DbMallocRawNN for the unusual and
+** slower case when the allocation cannot be fulfilled using lookaside.
+*/
+static SQLITE_NOINLINE void *dbMallocRawFinish(sqlite3 *db, u64 n){
+  void *p;
+  assert( db!=0 );
+  p = sqlite3Malloc(n);
+  if( !p ) sqlite3OomFault(db);
+  sqlite3MemdebugSetType(p,
+         (db->lookaside.bDisable==0) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP);
+  return p;
+}
+
+/*
+** Allocate memory, either lookaside (if possible) or heap.
+** If the allocation fails, set the mallocFailed flag in
+** the connection pointer.
+**
+** If db!=0 and db->mallocFailed is true (indicating a prior malloc
+** failure on the same database connection) then always return 0.
+** Hence for a particular database connection, once malloc starts
+** failing, it fails consistently until mallocFailed is reset.
+** This is an important assumption.  There are many places in the
+** code that do things like this:
+**
+**         int *a = (int*)sqlite3DbMallocRaw(db, 100);
+**         int *b = (int*)sqlite3DbMallocRaw(db, 200);
+**         if( b ) a[10] = 9;
+**
+** In other words, if a subsequent malloc (ex: "b") worked, it is assumed
+** that all prior mallocs (ex: "a") worked too.
+**
+** The sqlite3MallocRawNN() variant guarantees that the "db" parameter is
+** not a NULL pointer.
+*/
+SQLITE_PRIVATE void *sqlite3DbMallocRaw(sqlite3 *db, u64 n){
+  void *p;
+  if( db ) return sqlite3DbMallocRawNN(db, n);
+  p = sqlite3Malloc(n);
+  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+  return p;
+}
+SQLITE_PRIVATE void *sqlite3DbMallocRawNN(sqlite3 *db, u64 n){
+#ifndef SQLITE_OMIT_LOOKASIDE
+  LookasideSlot *pBuf;
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( db->pnBytesFreed==0 );
+  if( n>db->lookaside.sz ){
+    if( !db->lookaside.bDisable ){
+      db->lookaside.anStat[1]++;
+    }else if( db->mallocFailed ){
+      return 0;
+    }
+    return dbMallocRawFinish(db, n);
+  }
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  if( n<=LOOKASIDE_SMALL ){
+    if( (pBuf = db->lookaside.pSmallFree)!=0 ){
+      db->lookaside.pSmallFree = pBuf->pNext;
+      db->lookaside.anStat[0]++;
+      return (void*)pBuf;
+    }else if( (pBuf = db->lookaside.pSmallInit)!=0 ){
+      db->lookaside.pSmallInit = pBuf->pNext;
+      db->lookaside.anStat[0]++;
+      return (void*)pBuf;
+    }
+  }
+#endif
+  if( (pBuf = db->lookaside.pFree)!=0 ){
+    db->lookaside.pFree = pBuf->pNext;
+    db->lookaside.anStat[0]++;
+    return (void*)pBuf;
+  }else if( (pBuf = db->lookaside.pInit)!=0 ){
+    db->lookaside.pInit = pBuf->pNext;
+    db->lookaside.anStat[0]++;
+    return (void*)pBuf;
+  }else{
+    db->lookaside.anStat[2]++;
+  }
+#else
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( db->pnBytesFreed==0 );
+  if( db->mallocFailed ){
+    return 0;
+  }
+#endif
+  return dbMallocRawFinish(db, n);
+}
+
+/* Forward declaration */
+static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n);
+
+/*
+** Resize the block of memory pointed to by p to n bytes. If the
+** resize fails, set the mallocFailed flag in the connection object.
+*/
+SQLITE_PRIVATE void *sqlite3DbRealloc(sqlite3 *db, void *p, u64 n){
+  assert( db!=0 );
+  if( p==0 ) return sqlite3DbMallocRawNN(db, n);
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( ((uptr)p)<(uptr)db->lookaside.pEnd ){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+    if( ((uptr)p)>=(uptr)db->lookaside.pMiddle ){
+      if( n<=LOOKASIDE_SMALL ) return p;
+    }else
+#endif
+    if( ((uptr)p)>=(uptr)db->lookaside.pStart ){
+      if( n<=db->lookaside.szTrue ) return p;
+    }
+  }
+  return dbReallocFinish(db, p, n);
+}
+static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n){
+  void *pNew = 0;
+  assert( db!=0 );
+  assert( p!=0 );
+  if( db->mallocFailed==0 ){
+    if( isLookaside(db, p) ){
+      pNew = sqlite3DbMallocRawNN(db, n);
+      if( pNew ){
+        memcpy(pNew, p, lookasideMallocSize(db, p));
+        sqlite3DbFree(db, p);
+      }
+    }else{
+      assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+      assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+      pNew = sqlite3Realloc(p, n);
+      if( !pNew ){
+        sqlite3OomFault(db);
+      }
+      sqlite3MemdebugSetType(pNew,
+            (db->lookaside.bDisable==0 ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
+    }
+  }
+  return pNew;
+}
+
+/*
+** Attempt to reallocate p.  If the reallocation fails, then free p
+** and set the mallocFailed flag in the database connection.
+*/
+SQLITE_PRIVATE void *sqlite3DbReallocOrFree(sqlite3 *db, void *p, u64 n){
+  void *pNew;
+  pNew = sqlite3DbRealloc(db, p, n);
+  if( !pNew ){
+    sqlite3DbFree(db, p);
+  }
+  return pNew;
+}
+
+/*
+** Make a copy of a string in memory obtained from sqliteMalloc(). These
+** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This
+** is because when memory debugging is turned on, these two functions are
+** called via macros that record the current file and line number in the
+** ThreadData structure.
+*/
+SQLITE_PRIVATE char *sqlite3DbStrDup(sqlite3 *db, const char *z){
+  char *zNew;
+  size_t n;
+  if( z==0 ){
+    return 0;
+  }
+  n = strlen(z) + 1;
+  zNew = sqlite3DbMallocRaw(db, n);
+  if( zNew ){
+    memcpy(zNew, z, n);
+  }
+  return zNew;
+}
+SQLITE_PRIVATE char *sqlite3DbStrNDup(sqlite3 *db, const char *z, u64 n){
+  char *zNew;
+  assert( db!=0 );
+  assert( z!=0 || n==0 );
+  assert( (n&0x7fffffff)==n );
+  zNew = z ? sqlite3DbMallocRawNN(db, n+1) : 0;
+  if( zNew ){
+    memcpy(zNew, z, (size_t)n);
+    zNew[n] = 0;
+  }
+  return zNew;
+}
+
+/*
+** The text between zStart and zEnd represents a phrase within a larger
+** SQL statement.  Make a copy of this phrase in space obtained form
+** sqlite3DbMalloc().  Omit leading and trailing whitespace.
+*/
+SQLITE_PRIVATE char *sqlite3DbSpanDup(sqlite3 *db, const char *zStart, const char *zEnd){
+  int n;
+#ifdef SQLITE_DEBUG
+  /* Because of the way the parser works, the span is guaranteed to contain
+  ** at least one non-space character */
+  for(n=0; sqlite3Isspace(zStart[n]); n++){ assert( &zStart[n]<zEnd ); }
+#endif
+  while( sqlite3Isspace(zStart[0]) ) zStart++;
+  n = (int)(zEnd - zStart);
+  while( sqlite3Isspace(zStart[n-1]) ) n--;
+  return sqlite3DbStrNDup(db, zStart, n);
+}
+
+/*
+** Free any prior content in *pz and replace it with a copy of zNew.
+*/
+SQLITE_PRIVATE void sqlite3SetString(char **pz, sqlite3 *db, const char *zNew){
+  char *z = sqlite3DbStrDup(db, zNew);
+  sqlite3DbFree(db, *pz);
+  *pz = z;
+}
+
+/*
+** Call this routine to record the fact that an OOM (out-of-memory) error
+** has happened.  This routine will set db->mallocFailed, and also
+** temporarily disable the lookaside memory allocator and interrupt
+** any running VDBEs.
+**
+** Always return a NULL pointer so that this routine can be invoked using
+**
+**      return sqlite3OomFault(db);
+**
+** and thereby avoid unnecessary stack frame allocations for the overwhelmingly
+** common case where no OOM occurs.
+*/
+SQLITE_PRIVATE void *sqlite3OomFault(sqlite3 *db){
+  if( db->mallocFailed==0 && db->bBenignMalloc==0 ){
+    db->mallocFailed = 1;
+    if( db->nVdbeExec>0 ){
+      AtomicStore(&db->u1.isInterrupted, 1);
+    }
+    DisableLookaside;
+    if( db->pParse ){
+      Parse *pParse;
+      sqlite3ErrorMsg(db->pParse, "out of memory");
+      db->pParse->rc = SQLITE_NOMEM_BKPT;
+      for(pParse=db->pParse->pOuterParse; pParse; pParse = pParse->pOuterParse){
+        pParse->nErr++;
+        pParse->rc = SQLITE_NOMEM;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** This routine reactivates the memory allocator and clears the
+** db->mallocFailed flag as necessary.
+**
+** The memory allocator is not restarted if there are running
+** VDBEs.
+*/
+SQLITE_PRIVATE void sqlite3OomClear(sqlite3 *db){
+  if( db->mallocFailed && db->nVdbeExec==0 ){
+    db->mallocFailed = 0;
+    AtomicStore(&db->u1.isInterrupted, 0);
+    assert( db->lookaside.bDisable>0 );
+    EnableLookaside;
+  }
+}
+
+/*
+** Take actions at the end of an API call to deal with error codes.
+*/
+static SQLITE_NOINLINE int apiHandleError(sqlite3 *db, int rc){
+  if( db->mallocFailed || rc==SQLITE_IOERR_NOMEM ){
+    sqlite3OomClear(db);
+    sqlite3Error(db, SQLITE_NOMEM);
+    return SQLITE_NOMEM_BKPT;
+  }
+  return rc & db->errMask;
+}
+
+/*
+** This function must be called before exiting any API function (i.e.
+** returning control to the user) that has called sqlite3_malloc or
+** sqlite3_realloc.
+**
+** The returned value is normally a copy of the second argument to this
+** function. However, if a malloc() failure has occurred since the previous
+** invocation SQLITE_NOMEM is returned instead.
+**
+** If an OOM as occurred, then the connection error-code (the value
+** returned by sqlite3_errcode()) is set to SQLITE_NOMEM.
+*/
+SQLITE_PRIVATE int sqlite3ApiExit(sqlite3* db, int rc){
+  /* If the db handle must hold the connection handle mutex here.
+  ** Otherwise the read (and possible write) of db->mallocFailed
+  ** is unsafe, as is the call to sqlite3Error().
+  */
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( db->mallocFailed || rc ){
+    return apiHandleError(db, rc);
+  }
+  return 0;
+}
+
+/************** End of malloc.c **********************************************/
+/************** Begin file printf.c ******************************************/
+/*
+** The "printf" code that follows dates from the 1980's.  It is in
+** the public domain.
+**
+**************************************************************************
+**
+** This file contains code for a set of "printf"-like routines.  These
+** routines format strings much like the printf() from the standard C
+** library, though the implementation here has enhancements to support
+** SQLite.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** Conversion types fall into various categories as defined by the
+** following enumeration.
+*/
+#define etRADIX       0 /* non-decimal integer types.  %x %o */
+#define etFLOAT       1 /* Floating point.  %f */
+#define etEXP         2 /* Exponentional notation. %e and %E */
+#define etGENERIC     3 /* Floating or exponential, depending on exponent. %g */
+#define etSIZE        4 /* Return number of characters processed so far. %n */
+#define etSTRING      5 /* Strings. %s */
+#define etDYNSTRING   6 /* Dynamically allocated strings. %z */
+#define etPERCENT     7 /* Percent symbol. %% */
+#define etCHARX       8 /* Characters. %c */
+/* The rest are extensions, not normally found in printf() */
+#define etSQLESCAPE   9 /* Strings with '\'' doubled.  %q */
+#define etSQLESCAPE2 10 /* Strings with '\'' doubled and enclosed in '',
+                          NULL pointers replaced by SQL NULL.  %Q */
+#define etTOKEN      11 /* a pointer to a Token structure */
+#define etSRCITEM    12 /* a pointer to a SrcItem */
+#define etPOINTER    13 /* The %p conversion */
+#define etSQLESCAPE3 14 /* %w -> Strings with '\"' doubled */
+#define etORDINAL    15 /* %r -> 1st, 2nd, 3rd, 4th, etc.  English only */
+#define etDECIMAL    16 /* %d or %u, but not %x, %o */
+
+#define etINVALID    17 /* Any unrecognized conversion type */
+
+
+/*
+** An "etByte" is an 8-bit unsigned value.
+*/
+typedef unsigned char etByte;
+
+/*
+** Each builtin conversion character (ex: the 'd' in "%d") is described
+** by an instance of the following structure
+*/
+typedef struct et_info {   /* Information about each format field */
+  char fmttype;            /* The format field code letter */
+  etByte base;             /* The base for radix conversion */
+  etByte flags;            /* One or more of FLAG_ constants below */
+  etByte type;             /* Conversion paradigm */
+  etByte charset;          /* Offset into aDigits[] of the digits string */
+  etByte prefix;           /* Offset into aPrefix[] of the prefix string */
+} et_info;
+
+/*
+** Allowed values for et_info.flags
+*/
+#define FLAG_SIGNED    1     /* True if the value to convert is signed */
+#define FLAG_STRING    4     /* Allow infinite precision */
+
+
+/*
+** The following table is searched linearly, so it is good to put the
+** most frequently used conversion types first.
+*/
+static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
+static const char aPrefix[] = "-x0\000X0";
+static const et_info fmtinfo[] = {
+  {  'd', 10, 1, etDECIMAL,    0,  0 },
+  {  's',  0, 4, etSTRING,     0,  0 },
+  {  'g',  0, 1, etGENERIC,    30, 0 },
+  {  'z',  0, 4, etDYNSTRING,  0,  0 },
+  {  'q',  0, 4, etSQLESCAPE,  0,  0 },
+  {  'Q',  0, 4, etSQLESCAPE2, 0,  0 },
+  {  'w',  0, 4, etSQLESCAPE3, 0,  0 },
+  {  'c',  0, 0, etCHARX,      0,  0 },
+  {  'o',  8, 0, etRADIX,      0,  2 },
+  {  'u', 10, 0, etDECIMAL,    0,  0 },
+  {  'x', 16, 0, etRADIX,      16, 1 },
+  {  'X', 16, 0, etRADIX,      0,  4 },
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  {  'f',  0, 1, etFLOAT,      0,  0 },
+  {  'e',  0, 1, etEXP,        30, 0 },
+  {  'E',  0, 1, etEXP,        14, 0 },
+  {  'G',  0, 1, etGENERIC,    14, 0 },
+#endif
+  {  'i', 10, 1, etDECIMAL,    0,  0 },
+  {  'n',  0, 0, etSIZE,       0,  0 },
+  {  '%',  0, 0, etPERCENT,    0,  0 },
+  {  'p', 16, 0, etPOINTER,    0,  1 },
+
+  /* All the rest are undocumented and are for internal use only */
+  {  'T',  0, 0, etTOKEN,      0,  0 },
+  {  'S',  0, 0, etSRCITEM,    0,  0 },
+  {  'r', 10, 1, etORDINAL,    0,  0 },
+};
+
+/* Notes:
+**
+**    %S    Takes a pointer to SrcItem.  Shows name or database.name
+**    %!S   Like %S but prefer the zName over the zAlias
+*/
+
+/*
+** Set the StrAccum object to an error mode.
+*/
+SQLITE_PRIVATE void sqlite3StrAccumSetError(StrAccum *p, u8 eError){
+  assert( eError==SQLITE_NOMEM || eError==SQLITE_TOOBIG );
+  p->accError = eError;
+  if( p->mxAlloc ) sqlite3_str_reset(p);
+  if( eError==SQLITE_TOOBIG ) sqlite3ErrorToParser(p->db, eError);
+}
+
+/*
+** Extra argument values from a PrintfArguments object
+*/
+static sqlite3_int64 getIntArg(PrintfArguments *p){
+  if( p->nArg<=p->nUsed ) return 0;
+  return sqlite3_value_int64(p->apArg[p->nUsed++]);
+}
+static double getDoubleArg(PrintfArguments *p){
+  if( p->nArg<=p->nUsed ) return 0.0;
+  return sqlite3_value_double(p->apArg[p->nUsed++]);
+}
+static char *getTextArg(PrintfArguments *p){
+  if( p->nArg<=p->nUsed ) return 0;
+  return (char*)sqlite3_value_text(p->apArg[p->nUsed++]);
+}
+
+/*
+** Allocate memory for a temporary buffer needed for printf rendering.
+**
+** If the requested size of the temp buffer is larger than the size
+** of the output buffer in pAccum, then cause an SQLITE_TOOBIG error.
+** Do the size check before the memory allocation to prevent rogue
+** SQL from requesting large allocations using the precision or width
+** field of the printf() function.
+*/
+static char *printfTempBuf(sqlite3_str *pAccum, sqlite3_int64 n){
+  char *z;
+  if( pAccum->accError ) return 0;
+  if( n>pAccum->nAlloc && n>pAccum->mxAlloc ){
+    sqlite3StrAccumSetError(pAccum, SQLITE_TOOBIG);
+    return 0;
+  }
+  z = sqlite3DbMallocRaw(pAccum->db, n);
+  if( z==0 ){
+    sqlite3StrAccumSetError(pAccum, SQLITE_NOMEM);
+  }
+  return z;
+}
+
+/*
+** On machines with a small stack size, you can redefine the
+** SQLITE_PRINT_BUF_SIZE to be something smaller, if desired.
+*/
+#ifndef SQLITE_PRINT_BUF_SIZE
+# define SQLITE_PRINT_BUF_SIZE 70
+#endif
+#define etBUFSIZE SQLITE_PRINT_BUF_SIZE  /* Size of the output buffer */
+
+/*
+** Hard limit on the precision of floating-point conversions.
+*/
+#ifndef SQLITE_PRINTF_PRECISION_LIMIT
+# define SQLITE_FP_PRECISION_LIMIT 100000000
+#endif
+
+/*
+** Render a string given by "fmt" into the StrAccum object.
+*/
+SQLITE_API void sqlite3_str_vappendf(
+  sqlite3_str *pAccum,       /* Accumulate results here */
+  const char *fmt,           /* Format string */
+  va_list ap                 /* arguments */
+){
+  int c;                     /* Next character in the format string */
+  char *bufpt;               /* Pointer to the conversion buffer */
+  int precision;             /* Precision of the current field */
+  int length;                /* Length of the field */
+  int idx;                   /* A general purpose loop counter */
+  int width;                 /* Width of the current field */
+  etByte flag_leftjustify;   /* True if "-" flag is present */
+  etByte flag_prefix;        /* '+' or ' ' or 0 for prefix */
+  etByte flag_alternateform; /* True if "#" flag is present */
+  etByte flag_altform2;      /* True if "!" flag is present */
+  etByte flag_zeropad;       /* True if field width constant starts with zero */
+  etByte flag_long;          /* 1 for the "l" flag, 2 for "ll", 0 by default */
+  etByte done;               /* Loop termination flag */
+  etByte cThousand;          /* Thousands separator for %d and %u */
+  etByte xtype = etINVALID;  /* Conversion paradigm */
+  u8 bArgList;               /* True for SQLITE_PRINTF_SQLFUNC */
+  char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
+  sqlite_uint64 longvalue;   /* Value for integer types */
+  double realvalue;          /* Value for real types */
+  const et_info *infop;      /* Pointer to the appropriate info structure */
+  char *zOut;                /* Rendering buffer */
+  int nOut;                  /* Size of the rendering buffer */
+  char *zExtra = 0;          /* Malloced memory used by some conversion */
+  int exp, e2;               /* exponent of real numbers */
+  etByte flag_dp;            /* True if decimal point should be shown */
+  etByte flag_rtz;           /* True if trailing zeros should be removed */
+
+  PrintfArguments *pArgList = 0; /* Arguments for SQLITE_PRINTF_SQLFUNC */
+  char buf[etBUFSIZE];       /* Conversion buffer */
+
+  /* pAccum never starts out with an empty buffer that was obtained from
+  ** malloc().  This precondition is required by the mprintf("%z...")
+  ** optimization. */
+  assert( pAccum->nChar>0 || (pAccum->printfFlags&SQLITE_PRINTF_MALLOCED)==0 );
+
+  bufpt = 0;
+  if( (pAccum->printfFlags & SQLITE_PRINTF_SQLFUNC)!=0 ){
+    pArgList = va_arg(ap, PrintfArguments*);
+    bArgList = 1;
+  }else{
+    bArgList = 0;
+  }
+  for(; (c=(*fmt))!=0; ++fmt){
+    if( c!='%' ){
+      bufpt = (char *)fmt;
+#if HAVE_STRCHRNUL
+      fmt = strchrnul(fmt, '%');
+#else
+      do{ fmt++; }while( *fmt && *fmt != '%' );
+#endif
+      sqlite3_str_append(pAccum, bufpt, (int)(fmt - bufpt));
+      if( *fmt==0 ) break;
+    }
+    if( (c=(*++fmt))==0 ){
+      sqlite3_str_append(pAccum, "%", 1);
+      break;
+    }
+    /* Find out what flags are present */
+    flag_leftjustify = flag_prefix = cThousand =
+     flag_alternateform = flag_altform2 = flag_zeropad = 0;
+    done = 0;
+    width = 0;
+    flag_long = 0;
+    precision = -1;
+    do{
+      switch( c ){
+        case '-':   flag_leftjustify = 1;     break;
+        case '+':   flag_prefix = '+';        break;
+        case ' ':   flag_prefix = ' ';        break;
+        case '#':   flag_alternateform = 1;   break;
+        case '!':   flag_altform2 = 1;        break;
+        case '0':   flag_zeropad = 1;         break;
+        case ',':   cThousand = ',';          break;
+        default:    done = 1;                 break;
+        case 'l': {
+          flag_long = 1;
+          c = *++fmt;
+          if( c=='l' ){
+            c = *++fmt;
+            flag_long = 2;
+          }
+          done = 1;
+          break;
+        }
+        case '1': case '2': case '3': case '4': case '5':
+        case '6': case '7': case '8': case '9': {
+          unsigned wx = c - '0';
+          while( (c = *++fmt)>='0' && c<='9' ){
+            wx = wx*10 + c - '0';
+          }
+          testcase( wx>0x7fffffff );
+          width = wx & 0x7fffffff;
+#ifdef SQLITE_PRINTF_PRECISION_LIMIT
+          if( width>SQLITE_PRINTF_PRECISION_LIMIT ){
+            width = SQLITE_PRINTF_PRECISION_LIMIT;
+          }
+#endif
+          if( c!='.' && c!='l' ){
+            done = 1;
+          }else{
+            fmt--;
+          }
+          break;
+        }
+        case '*': {
+          if( bArgList ){
+            width = (int)getIntArg(pArgList);
+          }else{
+            width = va_arg(ap,int);
+          }
+          if( width<0 ){
+            flag_leftjustify = 1;
+            width = width >= -2147483647 ? -width : 0;
+          }
+#ifdef SQLITE_PRINTF_PRECISION_LIMIT
+          if( width>SQLITE_PRINTF_PRECISION_LIMIT ){
+            width = SQLITE_PRINTF_PRECISION_LIMIT;
+          }
+#endif
+          if( (c = fmt[1])!='.' && c!='l' ){
+            c = *++fmt;
+            done = 1;
+          }
+          break;
+        }
+        case '.': {
+          c = *++fmt;
+          if( c=='*' ){
+            if( bArgList ){
+              precision = (int)getIntArg(pArgList);
+            }else{
+              precision = va_arg(ap,int);
+            }
+            if( precision<0 ){
+              precision = precision >= -2147483647 ? -precision : -1;
+            }
+            c = *++fmt;
+          }else{
+            unsigned px = 0;
+            while( c>='0' && c<='9' ){
+              px = px*10 + c - '0';
+              c = *++fmt;
+            }
+            testcase( px>0x7fffffff );
+            precision = px & 0x7fffffff;
+          }
+#ifdef SQLITE_PRINTF_PRECISION_LIMIT
+          if( precision>SQLITE_PRINTF_PRECISION_LIMIT ){
+            precision = SQLITE_PRINTF_PRECISION_LIMIT;
+          }
+#endif
+          if( c=='l' ){
+            --fmt;
+          }else{
+            done = 1;
+          }
+          break;
+        }
+      }
+    }while( !done && (c=(*++fmt))!=0 );
+
+    /* Fetch the info entry for the field */
+    infop = &fmtinfo[0];
+    xtype = etINVALID;
+    for(idx=0; idx<ArraySize(fmtinfo); idx++){
+      if( c==fmtinfo[idx].fmttype ){
+        infop = &fmtinfo[idx];
+        xtype = infop->type;
+        break;
+      }
+    }
+
+    /*
+    ** At this point, variables are initialized as follows:
+    **
+    **   flag_alternateform          TRUE if a '#' is present.
+    **   flag_altform2               TRUE if a '!' is present.
+    **   flag_prefix                 '+' or ' ' or zero
+    **   flag_leftjustify            TRUE if a '-' is present or if the
+    **                               field width was negative.
+    **   flag_zeropad                TRUE if the width began with 0.
+    **   flag_long                   1 for "l", 2 for "ll"
+    **   width                       The specified field width.  This is
+    **                               always non-negative.  Zero is the default.
+    **   precision                   The specified precision.  The default
+    **                               is -1.
+    **   xtype                       The class of the conversion.
+    **   infop                       Pointer to the appropriate info struct.
+    */
+    assert( width>=0 );
+    assert( precision>=(-1) );
+    switch( xtype ){
+      case etPOINTER:
+        flag_long = sizeof(char*)==sizeof(i64) ? 2 :
+                     sizeof(char*)==sizeof(long int) ? 1 : 0;
+        /* no break */ deliberate_fall_through
+      case etORDINAL:
+      case etRADIX:
+        cThousand = 0;
+        /* no break */ deliberate_fall_through
+      case etDECIMAL:
+        if( infop->flags & FLAG_SIGNED ){
+          i64 v;
+          if( bArgList ){
+            v = getIntArg(pArgList);
+          }else if( flag_long ){
+            if( flag_long==2 ){
+              v = va_arg(ap,i64) ;
+            }else{
+              v = va_arg(ap,long int);
+            }
+          }else{
+            v = va_arg(ap,int);
+          }
+          if( v<0 ){
+            testcase( v==SMALLEST_INT64 );
+            testcase( v==(-1) );
+            longvalue = ~v;
+            longvalue++;
+            prefix = '-';
+          }else{
+            longvalue = v;
+            prefix = flag_prefix;
+          }
+        }else{
+          if( bArgList ){
+            longvalue = (u64)getIntArg(pArgList);
+          }else if( flag_long ){
+            if( flag_long==2 ){
+              longvalue = va_arg(ap,u64);
+            }else{
+              longvalue = va_arg(ap,unsigned long int);
+            }
+          }else{
+            longvalue = va_arg(ap,unsigned int);
+          }
+          prefix = 0;
+        }
+        if( longvalue==0 ) flag_alternateform = 0;
+        if( flag_zeropad && precision<width-(prefix!=0) ){
+          precision = width-(prefix!=0);
+        }
+        if( precision<etBUFSIZE-10-etBUFSIZE/3 ){
+          nOut = etBUFSIZE;
+          zOut = buf;
+        }else{
+          u64 n;
+          n = (u64)precision + 10;
+          if( cThousand ) n += precision/3;
+          zOut = zExtra = printfTempBuf(pAccum, n);
+          if( zOut==0 ) return;
+          nOut = (int)n;
+        }
+        bufpt = &zOut[nOut-1];
+        if( xtype==etORDINAL ){
+          static const char zOrd[] = "thstndrd";
+          int x = (int)(longvalue % 10);
+          if( x>=4 || (longvalue/10)%10==1 ){
+            x = 0;
+          }
+          *(--bufpt) = zOrd[x*2+1];
+          *(--bufpt) = zOrd[x*2];
+        }
+        {
+          const char *cset = &aDigits[infop->charset];
+          u8 base = infop->base;
+          do{                                           /* Convert to ascii */
+            *(--bufpt) = cset[longvalue%base];
+            longvalue = longvalue/base;
+          }while( longvalue>0 );
+        }
+        length = (int)(&zOut[nOut-1]-bufpt);
+        while( precision>length ){
+          *(--bufpt) = '0';                             /* Zero pad */
+          length++;
+        }
+        if( cThousand ){
+          int nn = (length - 1)/3;  /* Number of "," to insert */
+          int ix = (length - 1)%3 + 1;
+          bufpt -= nn;
+          for(idx=0; nn>0; idx++){
+            bufpt[idx] = bufpt[idx+nn];
+            ix--;
+            if( ix==0 ){
+              bufpt[++idx] = cThousand;
+              nn--;
+              ix = 3;
+            }
+          }
+        }
+        if( prefix ) *(--bufpt) = prefix;               /* Add sign */
+        if( flag_alternateform && infop->prefix ){      /* Add "0" or "0x" */
+          const char *pre;
+          char x;
+          pre = &aPrefix[infop->prefix];
+          for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
+        }
+        length = (int)(&zOut[nOut-1]-bufpt);
+        break;
+      case etFLOAT:
+      case etEXP:
+      case etGENERIC: {
+        FpDecode s;
+        int iRound;
+        int j;
+
+        if( bArgList ){
+          realvalue = getDoubleArg(pArgList);
+        }else{
+          realvalue = va_arg(ap,double);
+        }
+        if( precision<0 ) precision = 6;         /* Set default precision */
+#ifdef SQLITE_FP_PRECISION_LIMIT
+        if( precision>SQLITE_FP_PRECISION_LIMIT ){
+          precision = SQLITE_FP_PRECISION_LIMIT;
+        }
+#endif
+        if( xtype==etFLOAT ){
+          iRound = -precision;
+        }else if( xtype==etGENERIC ){
+          if( precision==0 ) precision = 1;
+          iRound = precision;
+        }else{
+          iRound = precision+1;
+        }
+        sqlite3FpDecode(&s, realvalue, iRound, flag_altform2 ? 26 : 16);
+        if( s.isSpecial ){
+          if( s.isSpecial==2 ){
+            bufpt = flag_zeropad ? "null" : "NaN";
+            length = sqlite3Strlen30(bufpt);
+            break;
+          }else if( flag_zeropad ){
+            s.z[0] = '9';
+            s.iDP = 1000;
+            s.n = 1;
+          }else{
+            memcpy(buf, "-Inf", 5);
+            bufpt = buf;
+            if( s.sign=='-' ){
+              /* no-op */
+            }else if( flag_prefix ){
+              buf[0] = flag_prefix;
+            }else{
+              bufpt++;
+            }
+            length = sqlite3Strlen30(bufpt);
+            break;
+          }
+        }
+        if( s.sign=='-' ){
+          prefix = '-';
+        }else{
+          prefix = flag_prefix;
+        }
+
+        exp = s.iDP-1;
+
+        /*
+        ** If the field type is etGENERIC, then convert to either etEXP
+        ** or etFLOAT, as appropriate.
+        */
+        if( xtype==etGENERIC ){
+          assert( precision>0 );
+          precision--;
+          flag_rtz = !flag_alternateform;
+          if( exp<-4 || exp>precision ){
+            xtype = etEXP;
+          }else{
+            precision = precision - exp;
+            xtype = etFLOAT;
+          }
+        }else{
+          flag_rtz = flag_altform2;
+        }
+        if( xtype==etEXP ){
+          e2 = 0;
+        }else{
+          e2 = s.iDP - 1;
+        }
+        bufpt = buf;
+        {
+          i64 szBufNeeded;           /* Size of a temporary buffer needed */
+          szBufNeeded = MAX(e2,0)+(i64)precision+(i64)width+15;
+          if( cThousand && e2>0 ) szBufNeeded += (e2+2)/3;
+          if( szBufNeeded > etBUFSIZE ){
+            bufpt = zExtra = printfTempBuf(pAccum, szBufNeeded);
+            if( bufpt==0 ) return;
+          }
+        }
+        zOut = bufpt;
+        flag_dp = (precision>0 ?1:0) | flag_alternateform | flag_altform2;
+        /* The sign in front of the number */
+        if( prefix ){
+          *(bufpt++) = prefix;
+        }
+        /* Digits prior to the decimal point */
+        j = 0;
+        if( e2<0 ){
+          *(bufpt++) = '0';
+        }else{
+          for(; e2>=0; e2--){
+            *(bufpt++) = j<s.n ? s.z[j++] : '0';
+            if( cThousand && (e2%3)==0 && e2>1 ) *(bufpt++) = ',';
+          }
+        }
+        /* The decimal point */
+        if( flag_dp ){
+          *(bufpt++) = '.';
+        }
+        /* "0" digits after the decimal point but before the first
+        ** significant digit of the number */
+        for(e2++; e2<0 && precision>0; precision--, e2++){
+          *(bufpt++) = '0';
+        }
+        /* Significant digits after the decimal point */
+        while( (precision--)>0 ){
+          *(bufpt++) = j<s.n ? s.z[j++] : '0';
+        }
+        /* Remove trailing zeros and the "." if no digits follow the "." */
+        if( flag_rtz && flag_dp ){
+          while( bufpt[-1]=='0' ) *(--bufpt) = 0;
+          assert( bufpt>zOut );
+          if( bufpt[-1]=='.' ){
+            if( flag_altform2 ){
+              *(bufpt++) = '0';
+            }else{
+              *(--bufpt) = 0;
+            }
+          }
+        }
+        /* Add the "eNNN" suffix */
+        if( xtype==etEXP ){
+          exp = s.iDP - 1;
+          *(bufpt++) = aDigits[infop->charset];
+          if( exp<0 ){
+            *(bufpt++) = '-'; exp = -exp;
+          }else{
+            *(bufpt++) = '+';
+          }
+          if( exp>=100 ){
+            *(bufpt++) = (char)((exp/100)+'0');        /* 100's digit */
+            exp %= 100;
+          }
+          *(bufpt++) = (char)(exp/10+'0');             /* 10's digit */
+          *(bufpt++) = (char)(exp%10+'0');             /* 1's digit */
+        }
+        *bufpt = 0;
+
+        /* The converted number is in buf[] and zero terminated. Output it.
+        ** Note that the number is in the usual order, not reversed as with
+        ** integer conversions. */
+        length = (int)(bufpt-zOut);
+        bufpt = zOut;
+
+        /* Special case:  Add leading zeros if the flag_zeropad flag is
+        ** set and we are not left justified */
+        if( flag_zeropad && !flag_leftjustify && length < width){
+          int i;
+          int nPad = width - length;
+          for(i=width; i>=nPad; i--){
+            bufpt[i] = bufpt[i-nPad];
+          }
+          i = prefix!=0;
+          while( nPad-- ) bufpt[i++] = '0';
+          length = width;
+        }
+        break;
+      }
+      case etSIZE:
+        if( !bArgList ){
+          *(va_arg(ap,int*)) = pAccum->nChar;
+        }
+        length = width = 0;
+        break;
+      case etPERCENT:
+        buf[0] = '%';
+        bufpt = buf;
+        length = 1;
+        break;
+      case etCHARX:
+        if( bArgList ){
+          bufpt = getTextArg(pArgList);
+          length = 1;
+          if( bufpt ){
+            buf[0] = c = *(bufpt++);
+            if( (c&0xc0)==0xc0 ){
+              while( length<4 && (bufpt[0]&0xc0)==0x80 ){
+                buf[length++] = *(bufpt++);
+              }
+            }
+          }else{
+            buf[0] = 0;
+          }
+        }else{
+          unsigned int ch = va_arg(ap,unsigned int);
+          if( ch<0x00080 ){
+            buf[0] = ch & 0xff;
+            length = 1;
+          }else if( ch<0x00800 ){
+            buf[0] = 0xc0 + (u8)((ch>>6)&0x1f);
+            buf[1] = 0x80 + (u8)(ch & 0x3f);
+            length = 2;
+          }else if( ch<0x10000 ){
+            buf[0] = 0xe0 + (u8)((ch>>12)&0x0f);
+            buf[1] = 0x80 + (u8)((ch>>6) & 0x3f);
+            buf[2] = 0x80 + (u8)(ch & 0x3f);
+            length = 3;
+          }else{
+            buf[0] = 0xf0 + (u8)((ch>>18) & 0x07);
+            buf[1] = 0x80 + (u8)((ch>>12) & 0x3f);
+            buf[2] = 0x80 + (u8)((ch>>6) & 0x3f);
+            buf[3] = 0x80 + (u8)(ch & 0x3f);
+            length = 4;
+          }
+        }
+        if( precision>1 ){
+          i64 nPrior = 1;
+          width -= precision-1;
+          if( width>1 && !flag_leftjustify ){
+            sqlite3_str_appendchar(pAccum, width-1, ' ');
+            width = 0;
+          }
+          sqlite3_str_append(pAccum, buf, length);
+          precision--;
+          while( precision > 1 ){
+            i64 nCopyBytes;
+            if( nPrior > precision-1 ) nPrior = precision - 1;
+            nCopyBytes = length*nPrior;
+            if( nCopyBytes + pAccum->nChar >= pAccum->nAlloc ){
+              sqlite3StrAccumEnlarge(pAccum, nCopyBytes);
+            }
+            if( pAccum->accError ) break;
+            sqlite3_str_append(pAccum,
+                 &pAccum->zText[pAccum->nChar-nCopyBytes], nCopyBytes);
+            precision -= nPrior;
+            nPrior *= 2;
+          }
+        }
+        bufpt = buf;
+        flag_altform2 = 1;
+        goto adjust_width_for_utf8;
+      case etSTRING:
+      case etDYNSTRING:
+        if( bArgList ){
+          bufpt = getTextArg(pArgList);
+          xtype = etSTRING;
+        }else{
+          bufpt = va_arg(ap,char*);
+        }
+        if( bufpt==0 ){
+          bufpt = "";
+        }else if( xtype==etDYNSTRING ){
+          if( pAccum->nChar==0
+           && pAccum->mxAlloc
+           && width==0
+           && precision<0
+           && pAccum->accError==0
+          ){
+            /* Special optimization for sqlite3_mprintf("%z..."):
+            ** Extend an existing memory allocation rather than creating
+            ** a new one. */
+            assert( (pAccum->printfFlags&SQLITE_PRINTF_MALLOCED)==0 );
+            pAccum->zText = bufpt;
+            pAccum->nAlloc = sqlite3DbMallocSize(pAccum->db, bufpt);
+            pAccum->nChar = 0x7fffffff & (int)strlen(bufpt);
+            pAccum->printfFlags |= SQLITE_PRINTF_MALLOCED;
+            length = 0;
+            break;
+          }
+          zExtra = bufpt;
+        }
+        if( precision>=0 ){
+          if( flag_altform2 ){
+            /* Set length to the number of bytes needed in order to display
+            ** precision characters */
+            unsigned char *z = (unsigned char*)bufpt;
+            while( precision-- > 0 && z[0] ){
+              SQLITE_SKIP_UTF8(z);
+            }
+            length = (int)(z - (unsigned char*)bufpt);
+          }else{
+            for(length=0; length<precision && bufpt[length]; length++){}
+          }
+        }else{
+          length = 0x7fffffff & (int)strlen(bufpt);
+        }
+      adjust_width_for_utf8:
+        if( flag_altform2 && width>0 ){
+          /* Adjust width to account for extra bytes in UTF-8 characters */
+          int ii = length - 1;
+          while( ii>=0 ) if( (bufpt[ii--] & 0xc0)==0x80 ) width++;
+        }
+        break;
+      case etSQLESCAPE:           /* %q: Escape ' characters */
+      case etSQLESCAPE2:          /* %Q: Escape ' and enclose in '...' */
+      case etSQLESCAPE3: {        /* %w: Escape " characters */
+        i64 i, j, k, n;
+        int needQuote, isnull;
+        char ch;
+        char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
+        char *escarg;
+
+        if( bArgList ){
+          escarg = getTextArg(pArgList);
+        }else{
+          escarg = va_arg(ap,char*);
+        }
+        isnull = escarg==0;
+        if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
+        /* For %q, %Q, and %w, the precision is the number of bytes (or
+        ** characters if the ! flags is present) to use from the input.
+        ** Because of the extra quoting characters inserted, the number
+        ** of output characters may be larger than the precision.
+        */
+        k = precision;
+        for(i=n=0; k!=0 && (ch=escarg[i])!=0; i++, k--){
+          if( ch==q )  n++;
+          if( flag_altform2 && (ch&0xc0)==0xc0 ){
+            while( (escarg[i+1]&0xc0)==0x80 ){ i++; }
+          }
+        }
+        needQuote = !isnull && xtype==etSQLESCAPE2;
+        n += i + 3;
+        if( n>etBUFSIZE ){
+          bufpt = zExtra = printfTempBuf(pAccum, n);
+          if( bufpt==0 ) return;
+        }else{
+          bufpt = buf;
+        }
+        j = 0;
+        if( needQuote ) bufpt[j++] = q;
+        k = i;
+        for(i=0; i<k; i++){
+          bufpt[j++] = ch = escarg[i];
+          if( ch==q ) bufpt[j++] = ch;
+        }
+        if( needQuote ) bufpt[j++] = q;
+        bufpt[j] = 0;
+        length = j;
+        goto adjust_width_for_utf8;
+      }
+      case etTOKEN: {
+        if( (pAccum->printfFlags & SQLITE_PRINTF_INTERNAL)==0 ) return;
+        if( flag_alternateform ){
+          /* %#T means an Expr pointer that uses Expr.u.zToken */
+          Expr *pExpr = va_arg(ap,Expr*);
+          if( ALWAYS(pExpr) && ALWAYS(!ExprHasProperty(pExpr,EP_IntValue)) ){
+            sqlite3_str_appendall(pAccum, (const char*)pExpr->u.zToken);
+            sqlite3RecordErrorOffsetOfExpr(pAccum->db, pExpr);
+          }
+        }else{
+          /* %T means a Token pointer */
+          Token *pToken = va_arg(ap, Token*);
+          assert( bArgList==0 );
+          if( pToken && pToken->n ){
+            sqlite3_str_append(pAccum, (const char*)pToken->z, pToken->n);
+            sqlite3RecordErrorByteOffset(pAccum->db, pToken->z);
+          }
+        }
+        length = width = 0;
+        break;
+      }
+      case etSRCITEM: {
+        SrcItem *pItem;
+        if( (pAccum->printfFlags & SQLITE_PRINTF_INTERNAL)==0 ) return;
+        pItem = va_arg(ap, SrcItem*);
+        assert( bArgList==0 );
+        if( pItem->zAlias && !flag_altform2 ){
+          sqlite3_str_appendall(pAccum, pItem->zAlias);
+        }else if( pItem->zName ){
+          if( pItem->fg.fixedSchema==0
+           && pItem->fg.isSubquery==0
+           && pItem->u4.zDatabase!=0
+          ){
+            sqlite3_str_appendall(pAccum, pItem->u4.zDatabase);
+            sqlite3_str_append(pAccum, ".", 1);
+          }
+          sqlite3_str_appendall(pAccum, pItem->zName);
+        }else if( pItem->zAlias ){
+          sqlite3_str_appendall(pAccum, pItem->zAlias);
+        }else if( ALWAYS(pItem->fg.isSubquery) ){/* Because of tag-20240424-1 */
+          Select *pSel = pItem->u4.pSubq->pSelect;
+          assert( pSel!=0 );
+          if( pSel->selFlags & SF_NestedFrom ){
+            sqlite3_str_appendf(pAccum, "(join-%u)", pSel->selId);
+          }else if( pSel->selFlags & SF_MultiValue ){
+            assert( !pItem->fg.isTabFunc && !pItem->fg.isIndexedBy );
+            sqlite3_str_appendf(pAccum, "%u-ROW VALUES CLAUSE",
+                                pItem->u1.nRow);
+          }else{
+            sqlite3_str_appendf(pAccum, "(subquery-%u)", pSel->selId);
+          }
+        }
+        length = width = 0;
+        break;
+      }
+      default: {
+        assert( xtype==etINVALID );
+        return;
+      }
+    }/* End switch over the format type */
+    /*
+    ** The text of the conversion is pointed to by "bufpt" and is
+    ** "length" characters long.  The field width is "width".  Do
+    ** the output.  Both length and width are in bytes, not characters,
+    ** at this point.  If the "!" flag was present on string conversions
+    ** indicating that width and precision should be expressed in characters,
+    ** then the values have been translated prior to reaching this point.
+    */
+    width -= length;
+    if( width>0 ){
+      if( !flag_leftjustify ) sqlite3_str_appendchar(pAccum, width, ' ');
+      sqlite3_str_append(pAccum, bufpt, length);
+      if( flag_leftjustify ) sqlite3_str_appendchar(pAccum, width, ' ');
+    }else{
+      sqlite3_str_append(pAccum, bufpt, length);
+    }
+
+    if( zExtra ){
+      sqlite3DbFree(pAccum->db, zExtra);
+      zExtra = 0;
+    }
+  }/* End for loop over the format string */
+} /* End of function */
+
+
+/*
+** The z string points to the first character of a token that is
+** associated with an error.  If db does not already have an error
+** byte offset recorded, try to compute the error byte offset for
+** z and set the error byte offset in db.
+*/
+SQLITE_PRIVATE void sqlite3RecordErrorByteOffset(sqlite3 *db, const char *z){
+  const Parse *pParse;
+  const char *zText;
+  const char *zEnd;
+  assert( z!=0 );
+  if( NEVER(db==0) ) return;
+  if( db->errByteOffset!=(-2) ) return;
+  pParse = db->pParse;
+  if( NEVER(pParse==0) ) return;
+  zText =pParse->zTail;
+  if( NEVER(zText==0) ) return;
+  zEnd = &zText[strlen(zText)];
+  if( SQLITE_WITHIN(z,zText,zEnd) ){
+    db->errByteOffset = (int)(z-zText);
+  }
+}
+
+/*
+** If pExpr has a byte offset for the start of a token, record that as
+** as the error offset.
+*/
+SQLITE_PRIVATE void sqlite3RecordErrorOffsetOfExpr(sqlite3 *db, const Expr *pExpr){
+  while( pExpr
+     && (ExprHasProperty(pExpr,EP_OuterON|EP_InnerON) || pExpr->w.iOfst<=0)
+  ){
+    pExpr = pExpr->pLeft;
+  }
+  if( pExpr==0 ) return;
+  if( ExprHasProperty(pExpr, EP_FromDDL) ) return;
+  db->errByteOffset = pExpr->w.iOfst;
+}
+
+/*
+** Enlarge the memory allocation on a StrAccum object so that it is
+** able to accept at least N more bytes of text.
+**
+** Return the number of bytes of text that StrAccum is able to accept
+** after the attempted enlargement.  The value returned might be zero.
+*/
+SQLITE_PRIVATE int sqlite3StrAccumEnlarge(StrAccum *p, i64 N){
+  char *zNew;
+  assert( p->nChar+N >= p->nAlloc ); /* Only called if really needed */
+  if( p->accError ){
+    testcase(p->accError==SQLITE_TOOBIG);
+    testcase(p->accError==SQLITE_NOMEM);
+    return 0;
+  }
+  if( p->mxAlloc==0 ){
+    sqlite3StrAccumSetError(p, SQLITE_TOOBIG);
+    return p->nAlloc - p->nChar - 1;
+  }else{
+    char *zOld = isMalloced(p) ? p->zText : 0;
+    i64 szNew = p->nChar + N + 1;
+    if( szNew+p->nChar<=p->mxAlloc ){
+      /* Force exponential buffer size growth as long as it does not overflow,
+      ** to avoid having to call this routine too often */
+      szNew += p->nChar;
+    }
+    if( szNew > p->mxAlloc ){
+      sqlite3_str_reset(p);
+      sqlite3StrAccumSetError(p, SQLITE_TOOBIG);
+      return 0;
+    }else{
+      p->nAlloc = (int)szNew;
+    }
+    if( p->db ){
+      zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
+    }else{
+      zNew = sqlite3Realloc(zOld, p->nAlloc);
+    }
+    if( zNew ){
+      assert( p->zText!=0 || p->nChar==0 );
+      if( !isMalloced(p) && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
+      p->zText = zNew;
+      p->nAlloc = sqlite3DbMallocSize(p->db, zNew);
+      p->printfFlags |= SQLITE_PRINTF_MALLOCED;
+    }else{
+      sqlite3_str_reset(p);
+      sqlite3StrAccumSetError(p, SQLITE_NOMEM);
+      return 0;
+    }
+  }
+  assert( N>=0 && N<=0x7fffffff );
+  return (int)N;
+}
+
+/*
+** Append N copies of character c to the given string buffer.
+*/
+SQLITE_API void sqlite3_str_appendchar(sqlite3_str *p, int N, char c){
+  testcase( p->nChar + (i64)N > 0x7fffffff );
+  if( p->nChar+(i64)N >= p->nAlloc && (N = sqlite3StrAccumEnlarge(p, N))<=0 ){
+    return;
+  }
+  while( (N--)>0 ) p->zText[p->nChar++] = c;
+}
+
+/*
+** The StrAccum "p" is not large enough to accept N new bytes of z[].
+** So enlarge if first, then do the append.
+**
+** This is a helper routine to sqlite3_str_append() that does special-case
+** work (enlarging the buffer) using tail recursion, so that the
+** sqlite3_str_append() routine can use fast calling semantics.
+*/
+static void SQLITE_NOINLINE enlargeAndAppend(StrAccum *p, const char *z, int N){
+  N = sqlite3StrAccumEnlarge(p, N);
+  if( N>0 ){
+    memcpy(&p->zText[p->nChar], z, N);
+    p->nChar += N;
+  }
+}
+
+/*
+** Append N bytes of text from z to the StrAccum object.  Increase the
+** size of the memory allocation for StrAccum if necessary.
+*/
+SQLITE_API void sqlite3_str_append(sqlite3_str *p, const char *z, int N){
+  assert( z!=0 || N==0 );
+  assert( p->zText!=0 || p->nChar==0 || p->accError );
+  assert( N>=0 );
+  assert( p->accError==0 || p->nAlloc==0 || p->mxAlloc==0 );
+  if( p->nChar+N >= p->nAlloc ){
+    enlargeAndAppend(p,z,N);
+  }else if( N ){
+    assert( p->zText );
+    p->nChar += N;
+    memcpy(&p->zText[p->nChar-N], z, N);
+  }
+}
+
+/*
+** Append the complete text of zero-terminated string z[] to the p string.
+*/
+SQLITE_API void sqlite3_str_appendall(sqlite3_str *p, const char *z){
+  sqlite3_str_append(p, z, sqlite3Strlen30(z));
+}
+
+
+/*
+** Finish off a string by making sure it is zero-terminated.
+** Return a pointer to the resulting string.  Return a NULL
+** pointer if any kind of error was encountered.
+*/
+static SQLITE_NOINLINE char *strAccumFinishRealloc(StrAccum *p){
+  char *zText;
+  assert( p->mxAlloc>0 && !isMalloced(p) );
+  zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
+  if( zText ){
+    memcpy(zText, p->zText, p->nChar+1);
+    p->printfFlags |= SQLITE_PRINTF_MALLOCED;
+  }else{
+    sqlite3StrAccumSetError(p, SQLITE_NOMEM);
+  }
+  p->zText = zText;
+  return zText;
+}
+SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum *p){
+  if( p->zText ){
+    p->zText[p->nChar] = 0;
+    if( p->mxAlloc>0 && !isMalloced(p) ){
+      return strAccumFinishRealloc(p);
+    }
+  }
+  return p->zText;
+}
+
+/*
+** Use the content of the StrAccum passed as the second argument
+** as the result of an SQL function.
+*/
+SQLITE_PRIVATE void sqlite3ResultStrAccum(sqlite3_context *pCtx, StrAccum *p){
+  if( p->accError ){
+    sqlite3_result_error_code(pCtx, p->accError);
+    sqlite3_str_reset(p);
+  }else if( isMalloced(p) ){
+    sqlite3_result_text(pCtx, p->zText, p->nChar, SQLITE_DYNAMIC);
+  }else{
+    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
+    sqlite3_str_reset(p);
+  }
+}
+
+/*
+** This singleton is an sqlite3_str object that is returned if
+** sqlite3_malloc() fails to provide space for a real one.  This
+** sqlite3_str object accepts no new text and always returns
+** an SQLITE_NOMEM error.
+*/
+static sqlite3_str sqlite3OomStr = {
+   0, 0, 0, 0, 0, SQLITE_NOMEM, 0
+};
+
+/* Finalize a string created using sqlite3_str_new().
+*/
+SQLITE_API char *sqlite3_str_finish(sqlite3_str *p){
+  char *z;
+  if( p!=0 && p!=&sqlite3OomStr ){
+    z = sqlite3StrAccumFinish(p);
+    sqlite3_free(p);
+  }else{
+    z = 0;
+  }
+  return z;
+}
+
+/* Return any error code associated with p */
+SQLITE_API int sqlite3_str_errcode(sqlite3_str *p){
+  return p ? p->accError : SQLITE_NOMEM;
+}
+
+/* Return the current length of p in bytes */
+SQLITE_API int sqlite3_str_length(sqlite3_str *p){
+  return p ? p->nChar : 0;
+}
+
+/* Return the current value for p */
+SQLITE_API char *sqlite3_str_value(sqlite3_str *p){
+  if( p==0 || p->nChar==0 ) return 0;
+  p->zText[p->nChar] = 0;
+  return p->zText;
+}
+
+/*
+** Reset an StrAccum string.  Reclaim all malloced memory.
+*/
+SQLITE_API void sqlite3_str_reset(StrAccum *p){
+  if( isMalloced(p) ){
+    sqlite3DbFree(p->db, p->zText);
+    p->printfFlags &= ~SQLITE_PRINTF_MALLOCED;
+  }
+  p->nAlloc = 0;
+  p->nChar = 0;
+  p->zText = 0;
+}
+
+/*
+** Initialize a string accumulator.
+**
+** p:     The accumulator to be initialized.
+** db:    Pointer to a database connection.  May be NULL.  Lookaside
+**        memory is used if not NULL. db->mallocFailed is set appropriately
+**        when not NULL.
+** zBase: An initial buffer.  May be NULL in which case the initial buffer
+**        is malloced.
+** n:     Size of zBase in bytes.  If total space requirements never exceed
+**        n then no memory allocations ever occur.
+** mx:    Maximum number of bytes to accumulate.  If mx==0 then no memory
+**        allocations will ever occur.
+*/
+SQLITE_PRIVATE void sqlite3StrAccumInit(StrAccum *p, sqlite3 *db, char *zBase, int n, int mx){
+  p->zText = zBase;
+  p->db = db;
+  p->nAlloc = n;
+  p->mxAlloc = mx;
+  p->nChar = 0;
+  p->accError = 0;
+  p->printfFlags = 0;
+}
+
+/* Allocate and initialize a new dynamic string object */
+SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3 *db){
+  sqlite3_str *p = sqlite3_malloc64(sizeof(*p));
+  if( p ){
+    sqlite3StrAccumInit(p, 0, 0, 0,
+            db ? db->aLimit[SQLITE_LIMIT_LENGTH] : SQLITE_MAX_LENGTH);
+  }else{
+    p = &sqlite3OomStr;
+  }
+  return p;
+}
+
+/*
+** Print into memory obtained from sqliteMalloc().  Use the internal
+** %-conversion extensions.
+*/
+SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){
+  char *z;
+  char zBase[SQLITE_PRINT_BUF_SIZE];
+  StrAccum acc;
+  assert( db!=0 );
+  sqlite3StrAccumInit(&acc, db, zBase, sizeof(zBase),
+                      db->aLimit[SQLITE_LIMIT_LENGTH]);
+  acc.printfFlags = SQLITE_PRINTF_INTERNAL;
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  z = sqlite3StrAccumFinish(&acc);
+  if( acc.accError==SQLITE_NOMEM ){
+    sqlite3OomFault(db);
+  }
+  return z;
+}
+
+/*
+** Print into memory obtained from sqliteMalloc().  Use the internal
+** %-conversion extensions.
+*/
+SQLITE_PRIVATE char *sqlite3MPrintf(sqlite3 *db, const char *zFormat, ...){
+  va_list ap;
+  char *z;
+  va_start(ap, zFormat);
+  z = sqlite3VMPrintf(db, zFormat, ap);
+  va_end(ap);
+  return z;
+}
+
+/*
+** Print into memory obtained from sqlite3_malloc().  Omit the internal
+** %-conversion extensions.
+*/
+SQLITE_API char *sqlite3_vmprintf(const char *zFormat, va_list ap){
+  char *z;
+  char zBase[SQLITE_PRINT_BUF_SIZE];
+  StrAccum acc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zFormat==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  sqlite3StrAccumInit(&acc, 0, zBase, sizeof(zBase), SQLITE_MAX_LENGTH);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  z = sqlite3StrAccumFinish(&acc);
+  return z;
+}
+
+/*
+** Print into memory obtained from sqlite3_malloc()().  Omit the internal
+** %-conversion extensions.
+*/
+SQLITE_API char *sqlite3_mprintf(const char *zFormat, ...){
+  va_list ap;
+  char *z;
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  va_start(ap, zFormat);
+  z = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+  return z;
+}
+
+/*
+** sqlite3_snprintf() works like snprintf() except that it ignores the
+** current locale settings.  This is important for SQLite because we
+** are not able to use a "," as the decimal point in place of "." as
+** specified by some locales.
+**
+** Oops:  The first two arguments of sqlite3_snprintf() are backwards
+** from the snprintf() standard.  Unfortunately, it is too late to change
+** this without breaking compatibility, so we just have to live with the
+** mistake.
+**
+** sqlite3_vsnprintf() is the varargs version.
+*/
+SQLITE_API char *sqlite3_vsnprintf(int n, char *zBuf, const char *zFormat, va_list ap){
+  StrAccum acc;
+  if( n<=0 ) return zBuf;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zBuf==0 || zFormat==0 ) {
+    (void)SQLITE_MISUSE_BKPT;
+    if( zBuf ) zBuf[0] = 0;
+    return zBuf;
+  }
+#endif
+  sqlite3StrAccumInit(&acc, 0, zBuf, n, 0);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  zBuf[acc.nChar] = 0;
+  return zBuf;
+}
+SQLITE_API char *sqlite3_snprintf(int n, char *zBuf, const char *zFormat, ...){
+  StrAccum acc;
+  va_list ap;
+  if( n<=0 ) return zBuf;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zBuf==0 || zFormat==0 ) {
+    (void)SQLITE_MISUSE_BKPT;
+    if( zBuf ) zBuf[0] = 0;
+    return zBuf;
+  }
+#endif
+  sqlite3StrAccumInit(&acc, 0, zBuf, n, 0);
+  va_start(ap,zFormat);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  va_end(ap);
+  zBuf[acc.nChar] = 0;
+  return zBuf;
+}
+
+/*
+** This is the routine that actually formats the sqlite3_log() message.
+** We house it in a separate routine from sqlite3_log() to avoid using
+** stack space on small-stack systems when logging is disabled.
+**
+** sqlite3_log() must render into a static buffer.  It cannot dynamically
+** allocate memory because it might be called while the memory allocator
+** mutex is held.
+**
+** sqlite3_str_vappendf() might ask for *temporary* memory allocations for
+** certain format characters (%q) or for very large precisions or widths.
+** Care must be taken that any sqlite3_log() calls that occur while the
+** memory mutex is held do not use these mechanisms.
+*/
+static void renderLogMsg(int iErrCode, const char *zFormat, va_list ap){
+  StrAccum acc;                          /* String accumulator */
+  char zMsg[SQLITE_PRINT_BUF_SIZE*3];    /* Complete log message */
+
+  sqlite3StrAccumInit(&acc, 0, zMsg, sizeof(zMsg), 0);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  sqlite3GlobalConfig.xLog(sqlite3GlobalConfig.pLogArg, iErrCode,
+                           sqlite3StrAccumFinish(&acc));
+}
+
+/*
+** Format and write a message to the log if logging is enabled.
+*/
+SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...){
+  va_list ap;                             /* Vararg list */
+  if( sqlite3GlobalConfig.xLog ){
+    va_start(ap, zFormat);
+    renderLogMsg(iErrCode, zFormat, ap);
+    va_end(ap);
+  }
+}
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+/*
+** A version of printf() that understands %lld.  Used for debugging.
+** The printf() built into some versions of windows does not understand %lld
+** and segfaults if you give it a long long int.
+*/
+SQLITE_PRIVATE void sqlite3DebugPrintf(const char *zFormat, ...){
+  va_list ap;
+  StrAccum acc;
+  char zBuf[SQLITE_PRINT_BUF_SIZE*10];
+  sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+  va_start(ap,zFormat);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  va_end(ap);
+  sqlite3StrAccumFinish(&acc);
+#ifdef SQLITE_OS_TRACE_PROC
+  {
+    extern void SQLITE_OS_TRACE_PROC(const char *zBuf, int nBuf);
+    SQLITE_OS_TRACE_PROC(zBuf, sizeof(zBuf));
+  }
+#else
+  fprintf(stdout,"%s", zBuf);
+  fflush(stdout);
+#endif
+}
+#endif
+
+
+/*
+** variable-argument wrapper around sqlite3_str_vappendf(). The bFlags argument
+** can contain the bit SQLITE_PRINTF_INTERNAL enable internal formats.
+*/
+SQLITE_API void sqlite3_str_appendf(StrAccum *p, const char *zFormat, ...){
+  va_list ap;
+  va_start(ap,zFormat);
+  sqlite3_str_vappendf(p, zFormat, ap);
+  va_end(ap);
+}
+
+
+/*****************************************************************************
+** Reference counted string/blob storage
+*****************************************************************************/
+
+/*
+** Increase the reference count of the string by one.
+**
+** The input parameter is returned.
+*/
+SQLITE_PRIVATE char *sqlite3RCStrRef(char *z){
+  RCStr *p = (RCStr*)z;
+  assert( p!=0 );
+  p--;
+  p->nRCRef++;
+  return z;
+}
+
+/*
+** Decrease the reference count by one.  Free the string when the
+** reference count reaches zero.
+*/
+SQLITE_PRIVATE void sqlite3RCStrUnref(void *z){
+  RCStr *p = (RCStr*)z;
+  assert( p!=0 );
+  p--;
+  assert( p->nRCRef>0 );
+  if( p->nRCRef>=2 ){
+    p->nRCRef--;
+  }else{
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Create a new string that is capable of holding N bytes of text, not counting
+** the zero byte at the end.  The string is uninitialized.
+**
+** The reference count is initially 1.  Call sqlite3RCStrUnref() to free the
+** newly allocated string.
+**
+** This routine returns 0 on an OOM.
+*/
+SQLITE_PRIVATE char *sqlite3RCStrNew(u64 N){
+  RCStr *p = sqlite3_malloc64( N + sizeof(*p) + 1 );
+  if( p==0 ) return 0;
+  p->nRCRef = 1;
+  return (char*)&p[1];
+}
+
+/*
+** Change the size of the string so that it is able to hold N bytes.
+** The string might be reallocated, so return the new allocation.
+*/
+SQLITE_PRIVATE char *sqlite3RCStrResize(char *z, u64 N){
+  RCStr *p = (RCStr*)z;
+  RCStr *pNew;
+  assert( p!=0 );
+  p--;
+  assert( p->nRCRef==1 );
+  pNew = sqlite3_realloc64(p, N+sizeof(RCStr)+1);
+  if( pNew==0 ){
+    sqlite3_free(p);
+    return 0;
+  }else{
+    return (char*)&pNew[1];
+  }
+}
+
+/************** End of printf.c **********************************************/
+/************** Begin file treeview.c ****************************************/
+/*
+** 2015-06-08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains C code to implement the TreeView debugging routines.
+** These routines print a parse tree to standard output for debugging and
+** analysis.
+**
+** The interfaces in this file is only available when compiling
+** with SQLITE_DEBUG.
+*/
+/* #include "sqliteInt.h" */
+#ifdef SQLITE_DEBUG
+
+/*
+** Add a new subitem to the tree.  The moreToFollow flag indicates that this
+** is not the last item in the tree.
+*/
+static void sqlite3TreeViewPush(TreeView **pp, u8 moreToFollow){
+  TreeView *p = *pp;
+  if( p==0 ){
+    *pp = p = sqlite3_malloc64( sizeof(*p) );
+    if( p==0 ) return;
+    memset(p, 0, sizeof(*p));
+  }else{
+    p->iLevel++;
+  }
+  assert( moreToFollow==0 || moreToFollow==1 );
+  if( p->iLevel<(int)sizeof(p->bLine) ) p->bLine[p->iLevel] = moreToFollow;
+}
+
+/*
+** Finished with one layer of the tree
+*/
+static void sqlite3TreeViewPop(TreeView **pp){
+  TreeView *p = *pp;
+  if( p==0 ) return;
+  p->iLevel--;
+  if( p->iLevel<0 ){
+    sqlite3_free(p);
+    *pp = 0;
+  }
+}
+
+/*
+** Generate a single line of output for the tree, with a prefix that contains
+** all the appropriate tree lines
+*/
+SQLITE_PRIVATE void sqlite3TreeViewLine(TreeView *p, const char *zFormat, ...){
+  va_list ap;
+  int i;
+  StrAccum acc;
+  char zBuf[1000];
+  sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+  if( p ){
+    for(i=0; i<p->iLevel && i<(int)sizeof(p->bLine)-1; i++){
+      sqlite3_str_append(&acc, p->bLine[i] ? "|   " : "    ", 4);
+    }
+    sqlite3_str_append(&acc, p->bLine[i] ? "|-- " : "'-- ", 4);
+  }
+  if( zFormat!=0 ){
+    va_start(ap, zFormat);
+    sqlite3_str_vappendf(&acc, zFormat, ap);
+    va_end(ap);
+    assert( acc.nChar>0 || acc.accError );
+    sqlite3_str_append(&acc, "\n", 1);
+  }
+  sqlite3StrAccumFinish(&acc);
+  fprintf(stdout,"%s", zBuf);
+  fflush(stdout);
+}
+
+/*
+** Shorthand for starting a new tree item that consists of a single label
+*/
+static void sqlite3TreeViewItem(TreeView *p, const char *zLabel,u8 moreFollows){
+  sqlite3TreeViewPush(&p, moreFollows);
+  sqlite3TreeViewLine(p, "%s", zLabel);
+}
+
+/*
+** Show a list of Column objects in tree format.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewColumnList(
+  TreeView *pView,
+  const Column *aCol,
+  int nCol,
+  u8 moreToFollow
+){
+  int i;
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  sqlite3TreeViewLine(pView, "COLUMNS");
+  for(i=0; i<nCol; i++){
+    u16 flg = aCol[i].colFlags;
+    int colMoreToFollow = i<(nCol - 1);
+    sqlite3TreeViewPush(&pView, colMoreToFollow);
+    sqlite3TreeViewLine(pView, 0);
+    printf(" %s", aCol[i].zCnName);
+    switch( aCol[i].eCType ){
+      case COLTYPE_ANY:      printf(" ANY");        break;
+      case COLTYPE_BLOB:     printf(" BLOB");       break;
+      case COLTYPE_INT:      printf(" INT");        break;
+      case COLTYPE_INTEGER:  printf(" INTEGER");    break;
+      case COLTYPE_REAL:     printf(" REAL");       break;
+      case COLTYPE_TEXT:     printf(" TEXT");       break;
+      case COLTYPE_CUSTOM: {
+        if( flg & COLFLAG_HASTYPE ){
+          const char *z = aCol[i].zCnName;
+          z += strlen(z)+1;
+          printf(" X-%s", z);
+          break;
+        }
+      }
+    }
+    if( flg & COLFLAG_PRIMKEY ) printf(" PRIMARY KEY");
+    if( flg & COLFLAG_HIDDEN ) printf(" HIDDEN");
+#ifdef COLFLAG_NOEXPAND
+    if( flg & COLFLAG_NOEXPAND ) printf(" NO-EXPAND");
+#endif
+    if( flg ) printf(" flags=%04x", flg);
+    printf("\n");
+    fflush(stdout);
+    sqlite3TreeViewPop(&pView);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+
+/*
+** Generate a human-readable description of a WITH clause.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewWith(TreeView *pView, const With *pWith, u8 moreToFollow){
+  int i;
+  if( pWith==0 ) return;
+  if( pWith->nCte==0 ) return;
+  if( pWith->pOuter ){
+    sqlite3TreeViewLine(pView, "WITH (0x%p, pOuter=0x%p)",pWith,pWith->pOuter);
+  }else{
+    sqlite3TreeViewLine(pView, "WITH (0x%p)", pWith);
+  }
+  if( pWith->nCte>0 ){
+    sqlite3TreeViewPush(&pView, moreToFollow);
+    for(i=0; i<pWith->nCte; i++){
+      StrAccum x;
+      char zLine[1000];
+      const struct Cte *pCte = &pWith->a[i];
+      sqlite3StrAccumInit(&x, 0, zLine, sizeof(zLine), 0);
+      sqlite3_str_appendf(&x, "%s", pCte->zName);
+      if( pCte->pCols && pCte->pCols->nExpr>0 ){
+        char cSep = '(';
+        int j;
+        for(j=0; j<pCte->pCols->nExpr; j++){
+          sqlite3_str_appendf(&x, "%c%s", cSep, pCte->pCols->a[j].zEName);
+          cSep = ',';
+        }
+        sqlite3_str_appendf(&x, ")");
+      }
+      if( pCte->eM10d!=M10d_Any ){
+        sqlite3_str_appendf(&x, " %sMATERIALIZED",
+           pCte->eM10d==M10d_No ? "NOT " : "");
+      }
+      if( pCte->pUse ){
+        sqlite3_str_appendf(&x, " (pUse=0x%p, nUse=%d)", pCte->pUse,
+                 pCte->pUse->nUse);
+      }
+      sqlite3StrAccumFinish(&x);
+      sqlite3TreeViewItem(pView, zLine, i<pWith->nCte-1);
+      sqlite3TreeViewSelect(pView, pCte->pSelect, 0);
+      sqlite3TreeViewPop(&pView);
+    }
+    sqlite3TreeViewPop(&pView);
+  }
+}
+
+/*
+** Generate a human-readable description of a SrcList object.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewSrcList(TreeView *pView, const SrcList *pSrc){
+  int i;
+  if( pSrc==0 ) return;
+  for(i=0; i<pSrc->nSrc; i++){
+    const SrcItem *pItem = &pSrc->a[i];
+    StrAccum x;
+    int n = 0;
+    char zLine[1000];
+    sqlite3StrAccumInit(&x, 0, zLine, sizeof(zLine), 0);
+    x.printfFlags |= SQLITE_PRINTF_INTERNAL;
+    sqlite3_str_appendf(&x, "{%d:*} %!S", pItem->iCursor, pItem);
+    if( pItem->pSTab ){
+      sqlite3_str_appendf(&x, " tab=%Q nCol=%d ptr=%p used=%llx%s",
+           pItem->pSTab->zName, pItem->pSTab->nCol, pItem->pSTab,
+           pItem->colUsed,
+           pItem->fg.rowidUsed ? "+rowid" : "");
+    }
+    if( (pItem->fg.jointype & (JT_LEFT|JT_RIGHT))==(JT_LEFT|JT_RIGHT) ){
+      sqlite3_str_appendf(&x, " FULL-OUTER-JOIN");
+    }else if( pItem->fg.jointype & JT_LEFT ){
+      sqlite3_str_appendf(&x, " LEFT-JOIN");
+    }else if( pItem->fg.jointype & JT_RIGHT ){
+      sqlite3_str_appendf(&x, " RIGHT-JOIN");
+    }else if( pItem->fg.jointype & JT_CROSS ){
+      sqlite3_str_appendf(&x, " CROSS-JOIN");
+    }
+    if( pItem->fg.jointype & JT_LTORJ ){
+      sqlite3_str_appendf(&x, " LTORJ");
+    }
+    if( pItem->fg.fromDDL ){
+      sqlite3_str_appendf(&x, " DDL");
+    }
+    if( pItem->fg.isCte ){
+      static const char *aMat[] = {",MAT", "", ",NO-MAT"};
+      sqlite3_str_appendf(&x, " CteUse=%d%s",
+                          pItem->u2.pCteUse->nUse,
+                          aMat[pItem->u2.pCteUse->eM10d]);
+    }
+    if( pItem->fg.isOn || (pItem->fg.isUsing==0 && pItem->u3.pOn!=0) ){
+      sqlite3_str_appendf(&x, " isOn");
+    }
+    if( pItem->fg.isTabFunc )      sqlite3_str_appendf(&x, " isTabFunc");
+    if( pItem->fg.isCorrelated )   sqlite3_str_appendf(&x, " isCorrelated");
+    if( pItem->fg.isMaterialized ) sqlite3_str_appendf(&x, " isMaterialized");
+    if( pItem->fg.viaCoroutine )   sqlite3_str_appendf(&x, " viaCoroutine");
+    if( pItem->fg.notCte )         sqlite3_str_appendf(&x, " notCte");
+    if( pItem->fg.isNestedFrom )   sqlite3_str_appendf(&x, " isNestedFrom");
+    if( pItem->fg.fixedSchema )    sqlite3_str_appendf(&x, " fixedSchema");
+    if( pItem->fg.hadSchema )      sqlite3_str_appendf(&x, " hadSchema");
+    if( pItem->fg.isSubquery )     sqlite3_str_appendf(&x, " isSubquery");
+
+    sqlite3StrAccumFinish(&x);
+    sqlite3TreeViewItem(pView, zLine, i<pSrc->nSrc-1);
+    n = 0;
+    if( pItem->fg.isSubquery ) n++;
+    if( pItem->fg.isTabFunc ) n++;
+    if( pItem->fg.isUsing ) n++;
+    if( pItem->fg.isUsing ){
+      sqlite3TreeViewIdList(pView, pItem->u3.pUsing, (--n)>0, "USING");
+    }
+    if( pItem->fg.isSubquery ){
+      assert( n==1 );
+      if( pItem->pSTab ){
+        Table *pTab = pItem->pSTab;
+        sqlite3TreeViewColumnList(pView, pTab->aCol, pTab->nCol, 1);
+      }
+      assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem) );
+      sqlite3TreeViewSelect(pView, pItem->u4.pSubq->pSelect, 0);
+    }
+    if( pItem->fg.isTabFunc ){
+      sqlite3TreeViewExprList(pView, pItem->u1.pFuncArg, 0, "func-args:");
+    }
+    sqlite3TreeViewPop(&pView);
+  }
+}
+
+/*
+** Generate a human-readable description of a Select object.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewSelect(TreeView *pView, const Select *p, u8 moreToFollow){
+  int n = 0;
+  int cnt = 0;
+  if( p==0 ){
+    sqlite3TreeViewLine(pView, "nil-SELECT");
+    return;
+  }
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  if( p->pWith ){
+    sqlite3TreeViewWith(pView, p->pWith, 1);
+    cnt = 1;
+    sqlite3TreeViewPush(&pView, 1);
+  }
+  do{
+    if( p->selFlags & SF_WhereBegin ){
+      sqlite3TreeViewLine(pView, "sqlite3WhereBegin()");
+    }else{
+      sqlite3TreeViewLine(pView,
+        "SELECT%s%s (%u/%p) selFlags=0x%x nSelectRow=%d",
+        ((p->selFlags & SF_Distinct) ? " DISTINCT" : ""),
+        ((p->selFlags & SF_Aggregate) ? " agg_flag" : ""),
+        p->selId, p, p->selFlags,
+        (int)p->nSelectRow
+      );
+    }
+    if( cnt++ ) sqlite3TreeViewPop(&pView);
+    if( p->pPrior ){
+      n = 1000;
+    }else{
+      n = 0;
+      if( p->pSrc && p->pSrc->nSrc && p->pSrc->nAlloc ) n++;
+      if( p->pWhere ) n++;
+      if( p->pGroupBy ) n++;
+      if( p->pHaving ) n++;
+      if( p->pOrderBy ) n++;
+      if( p->pLimit ) n++;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( p->pWin ) n++;
+      if( p->pWinDefn ) n++;
+#endif
+    }
+    if( p->pEList ){
+      sqlite3TreeViewExprList(pView, p->pEList, n>0, "result-set");
+    }
+    n--;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( p->pWin ){
+      Window *pX;
+      sqlite3TreeViewPush(&pView, (n--)>0);
+      sqlite3TreeViewLine(pView, "window-functions");
+      for(pX=p->pWin; pX; pX=pX->pNextWin){
+        sqlite3TreeViewWinFunc(pView, pX, pX->pNextWin!=0);
+      }
+      sqlite3TreeViewPop(&pView);
+    }
+#endif
+    if( p->pSrc && p->pSrc->nSrc && p->pSrc->nAlloc ){
+      sqlite3TreeViewPush(&pView, (n--)>0);
+      sqlite3TreeViewLine(pView, "FROM");
+      sqlite3TreeViewSrcList(pView, p->pSrc);
+      sqlite3TreeViewPop(&pView);
+    }
+    if( p->pWhere ){
+      sqlite3TreeViewItem(pView, "WHERE", (n--)>0);
+      sqlite3TreeViewExpr(pView, p->pWhere, 0);
+      sqlite3TreeViewPop(&pView);
+    }
+    if( p->pGroupBy ){
+      sqlite3TreeViewExprList(pView, p->pGroupBy, (n--)>0, "GROUPBY");
+    }
+    if( p->pHaving ){
+      sqlite3TreeViewItem(pView, "HAVING", (n--)>0);
+      sqlite3TreeViewExpr(pView, p->pHaving, 0);
+      sqlite3TreeViewPop(&pView);
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( p->pWinDefn ){
+      Window *pX;
+      sqlite3TreeViewItem(pView, "WINDOW", (n--)>0);
+      for(pX=p->pWinDefn; pX; pX=pX->pNextWin){
+        sqlite3TreeViewWindow(pView, pX, pX->pNextWin!=0);
+      }
+      sqlite3TreeViewPop(&pView);
+    }
+#endif
+    if( p->pOrderBy ){
+      sqlite3TreeViewExprList(pView, p->pOrderBy, (n--)>0, "ORDERBY");
+    }
+    if( p->pLimit ){
+      sqlite3TreeViewItem(pView, "LIMIT", (n--)>0);
+      sqlite3TreeViewExpr(pView, p->pLimit->pLeft, p->pLimit->pRight!=0);
+      if( p->pLimit->pRight ){
+        sqlite3TreeViewItem(pView, "OFFSET", 0);
+        sqlite3TreeViewExpr(pView, p->pLimit->pRight, 0);
+        sqlite3TreeViewPop(&pView);
+      }
+      sqlite3TreeViewPop(&pView);
+    }
+    if( p->pPrior ){
+      const char *zOp = "UNION";
+      switch( p->op ){
+        case TK_ALL:         zOp = "UNION ALL";  break;
+        case TK_INTERSECT:   zOp = "INTERSECT";  break;
+        case TK_EXCEPT:      zOp = "EXCEPT";     break;
+      }
+      sqlite3TreeViewItem(pView, zOp, 1);
+    }
+    p = p->pPrior;
+  }while( p!=0 );
+  sqlite3TreeViewPop(&pView);
+}
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Generate a description of starting or stopping bounds
+*/
+SQLITE_PRIVATE void sqlite3TreeViewBound(
+  TreeView *pView,        /* View context */
+  u8 eBound,              /* UNBOUNDED, CURRENT, PRECEDING, FOLLOWING */
+  Expr *pExpr,            /* Value for PRECEDING or FOLLOWING */
+  u8 moreToFollow         /* True if more to follow */
+){
+  switch( eBound ){
+    case TK_UNBOUNDED: {
+      sqlite3TreeViewItem(pView, "UNBOUNDED", moreToFollow);
+      sqlite3TreeViewPop(&pView);
+      break;
+    }
+    case TK_CURRENT: {
+      sqlite3TreeViewItem(pView, "CURRENT", moreToFollow);
+      sqlite3TreeViewPop(&pView);
+      break;
+    }
+    case TK_PRECEDING: {
+      sqlite3TreeViewItem(pView, "PRECEDING", moreToFollow);
+      sqlite3TreeViewExpr(pView, pExpr, 0);
+      sqlite3TreeViewPop(&pView);
+      break;
+    }
+    case TK_FOLLOWING: {
+      sqlite3TreeViewItem(pView, "FOLLOWING", moreToFollow);
+      sqlite3TreeViewExpr(pView, pExpr, 0);
+      sqlite3TreeViewPop(&pView);
+      break;
+    }
+  }
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Generate a human-readable explanation for a Window object
+*/
+SQLITE_PRIVATE void sqlite3TreeViewWindow(TreeView *pView, const Window *pWin, u8 more){
+  int nElement = 0;
+  if( pWin==0 ) return;
+  if( pWin->pFilter ){
+    sqlite3TreeViewItem(pView, "FILTER", 1);
+    sqlite3TreeViewExpr(pView, pWin->pFilter, 0);
+    sqlite3TreeViewPop(&pView);
+    if( pWin->eFrmType==TK_FILTER ) return;
+  }
+  sqlite3TreeViewPush(&pView, more);
+  if( pWin->zName ){
+    sqlite3TreeViewLine(pView, "OVER %s (%p)", pWin->zName, pWin);
+  }else{
+    sqlite3TreeViewLine(pView, "OVER (%p)", pWin);
+  }
+  if( pWin->zBase )    nElement++;
+  if( pWin->pOrderBy ) nElement++;
+  if( pWin->eFrmType!=0 && pWin->eFrmType!=TK_FILTER ) nElement++;
+  if( pWin->eExclude ) nElement++;
+  if( pWin->zBase ){
+    sqlite3TreeViewPush(&pView, (--nElement)>0);
+    sqlite3TreeViewLine(pView, "window: %s", pWin->zBase);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pWin->pPartition ){
+    sqlite3TreeViewExprList(pView, pWin->pPartition, nElement>0,"PARTITION-BY");
+  }
+  if( pWin->pOrderBy ){
+    sqlite3TreeViewExprList(pView, pWin->pOrderBy, (--nElement)>0, "ORDER-BY");
+  }
+  if( pWin->eFrmType!=0 && pWin->eFrmType!=TK_FILTER ){
+    char zBuf[30];
+    const char *zFrmType = "ROWS";
+    if( pWin->eFrmType==TK_RANGE ) zFrmType = "RANGE";
+    if( pWin->eFrmType==TK_GROUPS ) zFrmType = "GROUPS";
+    sqlite3_snprintf(sizeof(zBuf),zBuf,"%s%s",zFrmType,
+        pWin->bImplicitFrame ? " (implied)" : "");
+    sqlite3TreeViewItem(pView, zBuf, (--nElement)>0);
+    sqlite3TreeViewBound(pView, pWin->eStart, pWin->pStart, 1);
+    sqlite3TreeViewBound(pView, pWin->eEnd, pWin->pEnd, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pWin->eExclude ){
+    char zBuf[30];
+    const char *zExclude;
+    switch( pWin->eExclude ){
+      case TK_NO:      zExclude = "NO OTHERS";   break;
+      case TK_CURRENT: zExclude = "CURRENT ROW"; break;
+      case TK_GROUP:   zExclude = "GROUP";       break;
+      case TK_TIES:    zExclude = "TIES";        break;
+      default:
+        sqlite3_snprintf(sizeof(zBuf),zBuf,"invalid(%d)", pWin->eExclude);
+        zExclude = zBuf;
+        break;
+    }
+    sqlite3TreeViewPush(&pView, 0);
+    sqlite3TreeViewLine(pView, "EXCLUDE %s", zExclude);
+    sqlite3TreeViewPop(&pView);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Generate a human-readable explanation for a Window Function object
+*/
+SQLITE_PRIVATE void sqlite3TreeViewWinFunc(TreeView *pView, const Window *pWin, u8 more){
+  if( pWin==0 ) return;
+  sqlite3TreeViewPush(&pView, more);
+  sqlite3TreeViewLine(pView, "WINFUNC %s(%d)",
+                       pWin->pWFunc->zName, pWin->pWFunc->nArg);
+  sqlite3TreeViewWindow(pView, pWin, 0);
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** Generate a human-readable explanation of an expression tree.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewExpr(TreeView *pView, const Expr *pExpr, u8 moreToFollow){
+  const char *zBinOp = 0;   /* Binary operator */
+  const char *zUniOp = 0;   /* Unary operator */
+  char zFlgs[200];
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  if( pExpr==0 ){
+    sqlite3TreeViewLine(pView, "nil");
+    sqlite3TreeViewPop(&pView);
+    return;
+  }
+  if( pExpr->flags || pExpr->affExpr || pExpr->vvaFlags || pExpr->pAggInfo ){
+    StrAccum x;
+    sqlite3StrAccumInit(&x, 0, zFlgs, sizeof(zFlgs), 0);
+    sqlite3_str_appendf(&x, " fg.af=%x.%c",
+      pExpr->flags, pExpr->affExpr ? pExpr->affExpr : 'n');
+    if( ExprHasProperty(pExpr, EP_OuterON) ){
+      sqlite3_str_appendf(&x, " outer.iJoin=%d", pExpr->w.iJoin);
+    }
+    if( ExprHasProperty(pExpr, EP_InnerON) ){
+      sqlite3_str_appendf(&x, " inner.iJoin=%d", pExpr->w.iJoin);
+    }
+    if( ExprHasProperty(pExpr, EP_FromDDL) ){
+      sqlite3_str_appendf(&x, " DDL");
+    }
+    if( ExprHasVVAProperty(pExpr, EP_Immutable) ){
+      sqlite3_str_appendf(&x, " IMMUTABLE");
+    }
+    if( pExpr->pAggInfo!=0 ){
+      sqlite3_str_appendf(&x, " agg-column[%d]", pExpr->iAgg);
+    }
+    sqlite3StrAccumFinish(&x);
+  }else{
+    zFlgs[0] = 0;
+  }
+  switch( pExpr->op ){
+    case TK_AGG_COLUMN: {
+      sqlite3TreeViewLine(pView, "AGG{%d:%d}%s",
+            pExpr->iTable, pExpr->iColumn, zFlgs);
+      break;
+    }
+    case TK_COLUMN: {
+      if( pExpr->iTable<0 ){
+        /* This only happens when coding check constraints */
+        char zOp2[16];
+        if( pExpr->op2 ){
+          sqlite3_snprintf(sizeof(zOp2),zOp2," op2=0x%02x",pExpr->op2);
+        }else{
+          zOp2[0] = 0;
+        }
+        sqlite3TreeViewLine(pView, "COLUMN(%d)%s%s",
+                                    pExpr->iColumn, zFlgs, zOp2);
+      }else{
+        assert( ExprUseYTab(pExpr) );
+        sqlite3TreeViewLine(pView, "{%d:%d} pTab=%p%s",
+                        pExpr->iTable, pExpr->iColumn,
+                        pExpr->y.pTab, zFlgs);
+      }
+      if( ExprHasProperty(pExpr, EP_FixedCol) ){
+        sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      }
+      break;
+    }
+    case TK_INTEGER: {
+      if( pExpr->flags & EP_IntValue ){
+        sqlite3TreeViewLine(pView, "%d", pExpr->u.iValue);
+      }else{
+        sqlite3TreeViewLine(pView, "%s", pExpr->u.zToken);
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    case TK_FLOAT: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"%s", pExpr->u.zToken);
+      break;
+    }
+#endif
+    case TK_STRING: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"%Q", pExpr->u.zToken);
+      break;
+    }
+    case TK_NULL: {
+      sqlite3TreeViewLine(pView,"NULL");
+      break;
+    }
+    case TK_TRUEFALSE: {
+      sqlite3TreeViewLine(pView,"%s%s",
+         sqlite3ExprTruthValue(pExpr) ? "TRUE" : "FALSE", zFlgs);
+      break;
+    }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case TK_BLOB: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"%s", pExpr->u.zToken);
+      break;
+    }
+#endif
+    case TK_VARIABLE: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"VARIABLE(%s,%d)",
+                          pExpr->u.zToken, pExpr->iColumn);
+      break;
+    }
+    case TK_REGISTER: {
+      sqlite3TreeViewLine(pView,"REGISTER(%d)", pExpr->iTable);
+      break;
+    }
+    case TK_ID: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"ID \"%w\"", pExpr->u.zToken);
+      break;
+    }
+#ifndef SQLITE_OMIT_CAST
+    case TK_CAST: {
+      /* Expressions of the form:   CAST(pLeft AS token) */
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"CAST %Q", pExpr->u.zToken);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+#endif /* SQLITE_OMIT_CAST */
+    case TK_LT:      zBinOp = "LT";     break;
+    case TK_LE:      zBinOp = "LE";     break;
+    case TK_GT:      zBinOp = "GT";     break;
+    case TK_GE:      zBinOp = "GE";     break;
+    case TK_NE:      zBinOp = "NE";     break;
+    case TK_EQ:      zBinOp = "EQ";     break;
+    case TK_IS:      zBinOp = "IS";     break;
+    case TK_ISNOT:   zBinOp = "ISNOT";  break;
+    case TK_AND:     zBinOp = "AND";    break;
+    case TK_OR:      zBinOp = "OR";     break;
+    case TK_PLUS:    zBinOp = "ADD";    break;
+    case TK_STAR:    zBinOp = "MUL";    break;
+    case TK_MINUS:   zBinOp = "SUB";    break;
+    case TK_REM:     zBinOp = "REM";    break;
+    case TK_BITAND:  zBinOp = "BITAND"; break;
+    case TK_BITOR:   zBinOp = "BITOR";  break;
+    case TK_SLASH:   zBinOp = "DIV";    break;
+    case TK_LSHIFT:  zBinOp = "LSHIFT"; break;
+    case TK_RSHIFT:  zBinOp = "RSHIFT"; break;
+    case TK_CONCAT:  zBinOp = "CONCAT"; break;
+    case TK_DOT:     zBinOp = "DOT";    break;
+    case TK_LIMIT:   zBinOp = "LIMIT";  break;
+
+    case TK_UMINUS:  zUniOp = "UMINUS"; break;
+    case TK_UPLUS:   zUniOp = "UPLUS";  break;
+    case TK_BITNOT:  zUniOp = "BITNOT"; break;
+    case TK_NOT:     zUniOp = "NOT";    break;
+    case TK_ISNULL:  zUniOp = "ISNULL"; break;
+    case TK_NOTNULL: zUniOp = "NOTNULL"; break;
+
+    case TK_TRUTH: {
+      int x;
+      const char *azOp[] = {
+         "IS-FALSE", "IS-TRUE", "IS-NOT-FALSE", "IS-NOT-TRUE"
+      };
+      assert( pExpr->op2==TK_IS || pExpr->op2==TK_ISNOT );
+      assert( pExpr->pRight );
+      assert( sqlite3ExprSkipCollateAndLikely(pExpr->pRight)->op
+                  == TK_TRUEFALSE );
+      x = (pExpr->op2==TK_ISNOT)*2 + sqlite3ExprTruthValue(pExpr->pRight);
+      zUniOp = azOp[x];
+      break;
+    }
+
+    case TK_SPAN: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView, "SPAN %Q", pExpr->u.zToken);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+
+    case TK_COLLATE: {
+      /* COLLATE operators without the EP_Collate flag are intended to
+      ** emulate collation associated with a table column.  These show
+      ** up in the treeview output as "SOFT-COLLATE".  Explicit COLLATE
+      ** operators that appear in the original SQL always have the
+      ** EP_Collate bit set and appear in treeview output as just "COLLATE" */
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView, "%sCOLLATE %Q%s",
+        !ExprHasProperty(pExpr, EP_Collate) ? "SOFT-" : "",
+        pExpr->u.zToken, zFlgs);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+
+    case TK_AGG_FUNCTION:
+    case TK_FUNCTION: {
+      ExprList *pFarg;       /* List of function arguments */
+      Window *pWin;
+      if( ExprHasProperty(pExpr, EP_TokenOnly) ){
+        pFarg = 0;
+        pWin = 0;
+      }else{
+        assert( ExprUseXList(pExpr) );
+        pFarg = pExpr->x.pList;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        pWin = IsWindowFunc(pExpr) ? pExpr->y.pWin : 0;
+#else
+        pWin = 0;
+#endif
+      }
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      if( pExpr->op==TK_AGG_FUNCTION ){
+        sqlite3TreeViewLine(pView, "AGG_FUNCTION%d %Q%s agg=%d[%d]/%p",
+                             pExpr->op2, pExpr->u.zToken, zFlgs,
+                             pExpr->pAggInfo ? pExpr->pAggInfo->selId : 0,
+                             pExpr->iAgg, pExpr->pAggInfo);
+      }else if( pExpr->op2!=0 ){
+        const char *zOp2;
+        char zBuf[8];
+        sqlite3_snprintf(sizeof(zBuf),zBuf,"0x%02x",pExpr->op2);
+        zOp2 = zBuf;
+        if( pExpr->op2==NC_IsCheck ) zOp2 = "NC_IsCheck";
+        if( pExpr->op2==NC_IdxExpr ) zOp2 = "NC_IdxExpr";
+        if( pExpr->op2==NC_PartIdx ) zOp2 = "NC_PartIdx";
+        if( pExpr->op2==NC_GenCol ) zOp2 = "NC_GenCol";
+        sqlite3TreeViewLine(pView, "FUNCTION %Q%s op2=%s",
+                            pExpr->u.zToken, zFlgs, zOp2);
+      }else{
+        sqlite3TreeViewLine(pView, "FUNCTION %Q%s", pExpr->u.zToken, zFlgs);
+      }
+      if( pFarg ){
+        sqlite3TreeViewExprList(pView, pFarg, pWin!=0 || pExpr->pLeft, 0);
+        if( pExpr->pLeft ){
+          Expr *pOB = pExpr->pLeft;
+          assert( pOB->op==TK_ORDER );
+          assert( ExprUseXList(pOB) );
+          sqlite3TreeViewExprList(pView, pOB->x.pList, pWin!=0, "ORDERBY");
+        }
+      }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( pWin ){
+        sqlite3TreeViewWindow(pView, pWin, 0);
+      }
+#endif
+      break;
+    }
+    case TK_ORDER: {
+      sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, "ORDERBY");
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_EXISTS: {
+      assert( ExprUseXSelect(pExpr) );
+      sqlite3TreeViewLine(pView, "EXISTS-expr flags=0x%x", pExpr->flags);
+      sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
+      break;
+    }
+    case TK_SELECT: {
+      assert( ExprUseXSelect(pExpr) );
+      sqlite3TreeViewLine(pView, "subquery-expr flags=0x%x", pExpr->flags);
+      sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
+      break;
+    }
+    case TK_IN: {
+      sqlite3_str *pStr = sqlite3_str_new(0);
+      char *z;
+      sqlite3_str_appendf(pStr, "IN flags=0x%x", pExpr->flags);
+      if( pExpr->iTable ) sqlite3_str_appendf(pStr, " iTable=%d",pExpr->iTable);
+      if( ExprHasProperty(pExpr, EP_Subrtn) ){
+        sqlite3_str_appendf(pStr, " subrtn(%d,%d)",
+            pExpr->y.sub.regReturn, pExpr->y.sub.iAddr);
+      }
+      z = sqlite3_str_finish(pStr);
+      sqlite3TreeViewLine(pView, z);
+      sqlite3_free(z);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
+      if( ExprUseXSelect(pExpr) ){
+        sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
+      }else{
+        sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, 0);
+      }
+      break;
+    }
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+    /*
+    **    x BETWEEN y AND z
+    **
+    ** This is equivalent to
+    **
+    **    x>=y AND x<=z
+    **
+    ** X is stored in pExpr->pLeft.
+    ** Y is stored in pExpr->pList->a[0].pExpr.
+    ** Z is stored in pExpr->pList->a[1].pExpr.
+    */
+    case TK_BETWEEN: {
+      const Expr *pX, *pY, *pZ;
+      pX = pExpr->pLeft;
+      assert( ExprUseXList(pExpr) );
+      assert( pExpr->x.pList->nExpr==2 );
+      pY = pExpr->x.pList->a[0].pExpr;
+      pZ = pExpr->x.pList->a[1].pExpr;
+      sqlite3TreeViewLine(pView, "BETWEEN%s", zFlgs);
+      sqlite3TreeViewExpr(pView, pX, 1);
+      sqlite3TreeViewExpr(pView, pY, 1);
+      sqlite3TreeViewExpr(pView, pZ, 0);
+      break;
+    }
+    case TK_TRIGGER: {
+      /* If the opcode is TK_TRIGGER, then the expression is a reference
+      ** to a column in the new.* or old.* pseudo-tables available to
+      ** trigger programs. In this case Expr.iTable is set to 1 for the
+      ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
+      ** is set to the column of the pseudo-table to read, or to -1 to
+      ** read the rowid field.
+      */
+      sqlite3TreeViewLine(pView, "%s(%d)",
+          pExpr->iTable ? "NEW" : "OLD", pExpr->iColumn);
+      break;
+    }
+    case TK_CASE: {
+      sqlite3TreeViewLine(pView, "CASE");
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
+      assert( ExprUseXList(pExpr) );
+      sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, 0);
+      break;
+    }
+#ifndef SQLITE_OMIT_TRIGGER
+    case TK_RAISE: {
+      const char *zType = "unk";
+      switch( pExpr->affExpr ){
+        case OE_Rollback:   zType = "rollback";  break;
+        case OE_Abort:      zType = "abort";     break;
+        case OE_Fail:       zType = "fail";      break;
+        case OE_Ignore:     zType = "ignore";    break;
+      }
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView, "RAISE %s", zType);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+#endif
+    case TK_MATCH: {
+      sqlite3TreeViewLine(pView, "MATCH {%d:%d}%s",
+                          pExpr->iTable, pExpr->iColumn, zFlgs);
+      sqlite3TreeViewExpr(pView, pExpr->pRight, 0);
+      break;
+    }
+    case TK_VECTOR: {
+      char *z = sqlite3_mprintf("VECTOR%s",zFlgs);
+      assert( ExprUseXList(pExpr) );
+      sqlite3TreeViewBareExprList(pView, pExpr->x.pList, z);
+      sqlite3_free(z);
+      break;
+    }
+    case TK_SELECT_COLUMN: {
+      sqlite3TreeViewLine(pView, "SELECT-COLUMN %d of [0..%d]%s",
+              pExpr->iColumn, pExpr->iTable-1,
+              pExpr->pRight==pExpr->pLeft ? " (SELECT-owner)" : "");
+      assert( ExprUseXSelect(pExpr->pLeft) );
+      sqlite3TreeViewSelect(pView, pExpr->pLeft->x.pSelect, 0);
+      break;
+    }
+    case TK_IF_NULL_ROW: {
+      sqlite3TreeViewLine(pView, "IF-NULL-ROW %d", pExpr->iTable);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+    case TK_ERROR: {
+      Expr tmp;
+      sqlite3TreeViewLine(pView, "ERROR");
+      tmp = *pExpr;
+      tmp.op = pExpr->op2;
+      sqlite3TreeViewExpr(pView, &tmp, 0);
+      break;
+    }
+    case TK_ROW: {
+      if( pExpr->iColumn<=0 ){
+        sqlite3TreeViewLine(pView, "First FROM table rowid");
+      }else{
+        sqlite3TreeViewLine(pView, "First FROM table column %d",
+            pExpr->iColumn-1);
+      }
+      break;
+    }
+    default: {
+      sqlite3TreeViewLine(pView, "op=%d", pExpr->op);
+      break;
+    }
+  }
+  if( zBinOp ){
+    sqlite3TreeViewLine(pView, "%s%s", zBinOp, zFlgs);
+    sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
+    sqlite3TreeViewExpr(pView, pExpr->pRight, 0);
+  }else if( zUniOp ){
+    sqlite3TreeViewLine(pView, "%s%s", zUniOp, zFlgs);
+   sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+
+
+/*
+** Generate a human-readable explanation of an expression list.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewBareExprList(
+  TreeView *pView,
+  const ExprList *pList,
+  const char *zLabel
+){
+  if( zLabel==0 || zLabel[0]==0 ) zLabel = "LIST";
+  if( pList==0 ){
+    sqlite3TreeViewLine(pView, "%s (empty)", zLabel);
+  }else{
+    int i;
+    sqlite3TreeViewLine(pView, "%s", zLabel);
+    for(i=0; i<pList->nExpr; i++){
+      int j = pList->a[i].u.x.iOrderByCol;
+      u8 sortFlags = pList->a[i].fg.sortFlags;
+      char *zName = pList->a[i].zEName;
+      int moreToFollow = i<pList->nExpr - 1;
+      if( j || zName || sortFlags ){
+        sqlite3TreeViewPush(&pView, moreToFollow);
+        moreToFollow = 0;
+        sqlite3TreeViewLine(pView, 0);
+        if( zName ){
+          switch( pList->a[i].fg.eEName ){
+            default:
+              fprintf(stdout, "AS %s ", zName);
+              break;
+            case ENAME_TAB:
+              fprintf(stdout, "TABLE-ALIAS-NAME(\"%s\") ", zName);
+              if( pList->a[i].fg.bUsed ) fprintf(stdout, "(used) ");
+              if( pList->a[i].fg.bUsingTerm ) fprintf(stdout, "(USING-term) ");
+              if( pList->a[i].fg.bNoExpand ) fprintf(stdout, "(NoExpand) ");
+              break;
+            case ENAME_SPAN:
+              fprintf(stdout, "SPAN(\"%s\") ", zName);
+              break;
+          }
+        }
+        if( j ){
+          fprintf(stdout, "iOrderByCol=%d ", j);
+        }
+        if( sortFlags & KEYINFO_ORDER_DESC ){
+          fprintf(stdout, "DESC ");
+        }else if( sortFlags & KEYINFO_ORDER_BIGNULL ){
+          fprintf(stdout, "NULLS-LAST");
+        }
+        fprintf(stdout, "\n");
+        fflush(stdout);
+      }
+      sqlite3TreeViewExpr(pView, pList->a[i].pExpr, moreToFollow);
+      if( j || zName || sortFlags ){
+        sqlite3TreeViewPop(&pView);
+      }
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3TreeViewExprList(
+  TreeView *pView,
+  const ExprList *pList,
+  u8 moreToFollow,
+  const char *zLabel
+){
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  sqlite3TreeViewBareExprList(pView, pList, zLabel);
+  sqlite3TreeViewPop(&pView);
+}
+
+/*
+** Generate a human-readable explanation of an id-list.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewBareIdList(
+  TreeView *pView,
+  const IdList *pList,
+  const char *zLabel
+){
+  if( zLabel==0 || zLabel[0]==0 ) zLabel = "LIST";
+  if( pList==0 ){
+    sqlite3TreeViewLine(pView, "%s (empty)", zLabel);
+  }else{
+    int i;
+    sqlite3TreeViewLine(pView, "%s", zLabel);
+    for(i=0; i<pList->nId; i++){
+      char *zName = pList->a[i].zName;
+      int moreToFollow = i<pList->nId - 1;
+      if( zName==0 ) zName = "(null)";
+      sqlite3TreeViewPush(&pView, moreToFollow);
+      sqlite3TreeViewLine(pView, 0);
+      fprintf(stdout, "%s\n", zName);
+      sqlite3TreeViewPop(&pView);
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3TreeViewIdList(
+  TreeView *pView,
+  const IdList *pList,
+  u8 moreToFollow,
+  const char *zLabel
+){
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  sqlite3TreeViewBareIdList(pView, pList, zLabel);
+  sqlite3TreeViewPop(&pView);
+}
+
+/*
+** Generate a human-readable explanation of a list of Upsert objects
+*/
+SQLITE_PRIVATE void sqlite3TreeViewUpsert(
+  TreeView *pView,
+  const Upsert *pUpsert,
+  u8 moreToFollow
+){
+  if( pUpsert==0 ) return;
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  while( pUpsert ){
+    int n;
+    sqlite3TreeViewPush(&pView, pUpsert->pNextUpsert!=0 || moreToFollow);
+    sqlite3TreeViewLine(pView, "ON CONFLICT DO %s",
+         pUpsert->isDoUpdate ? "UPDATE" : "NOTHING");
+    n = (pUpsert->pUpsertSet!=0) + (pUpsert->pUpsertWhere!=0);
+    sqlite3TreeViewExprList(pView, pUpsert->pUpsertTarget, (n--)>0, "TARGET");
+    sqlite3TreeViewExprList(pView, pUpsert->pUpsertSet, (n--)>0, "SET");
+    if( pUpsert->pUpsertWhere ){
+      sqlite3TreeViewItem(pView, "WHERE", (n--)>0);
+      sqlite3TreeViewExpr(pView, pUpsert->pUpsertWhere, 0);
+      sqlite3TreeViewPop(&pView);
+    }
+    sqlite3TreeViewPop(&pView);
+    pUpsert = pUpsert->pNextUpsert;
+  }
+  sqlite3TreeViewPop(&pView);
+}
+
+#if TREETRACE_ENABLED
+/*
+** Generate a human-readable diagram of the data structure that go
+** into generating an DELETE statement.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewDelete(
+  const With *pWith,
+  const SrcList *pTabList,
+  const Expr *pWhere,
+  const ExprList *pOrderBy,
+  const Expr *pLimit,
+  const Trigger *pTrigger
+){
+  int n = 0;
+  TreeView *pView = 0;
+  sqlite3TreeViewPush(&pView, 0);
+  sqlite3TreeViewLine(pView, "DELETE");
+  if( pWith ) n++;
+  if( pTabList ) n++;
+  if( pWhere ) n++;
+  if( pOrderBy ) n++;
+  if( pLimit ) n++;
+  if( pTrigger ) n++;
+  if( pWith ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewWith(pView, pWith, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTabList ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "FROM");
+    sqlite3TreeViewSrcList(pView, pTabList);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pWhere ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "WHERE");
+    sqlite3TreeViewExpr(pView, pWhere, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pOrderBy ){
+    sqlite3TreeViewExprList(pView, pOrderBy, (--n)>0, "ORDER-BY");
+  }
+  if( pLimit ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "LIMIT");
+    sqlite3TreeViewExpr(pView, pLimit, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTrigger ){
+    sqlite3TreeViewTrigger(pView, pTrigger, (--n)>0, 1);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* TREETRACE_ENABLED */
+
+#if TREETRACE_ENABLED
+/*
+** Generate a human-readable diagram of the data structure that go
+** into generating an INSERT statement.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewInsert(
+  const With *pWith,
+  const SrcList *pTabList,
+  const IdList *pColumnList,
+  const Select *pSelect,
+  const ExprList *pExprList,
+  int onError,
+  const Upsert *pUpsert,
+  const Trigger *pTrigger
+){
+  TreeView *pView = 0;
+  int n = 0;
+  const char *zLabel = "INSERT";
+  switch( onError ){
+    case OE_Replace:  zLabel = "REPLACE";             break;
+    case OE_Ignore:   zLabel = "INSERT OR IGNORE";    break;
+    case OE_Rollback: zLabel = "INSERT OR ROLLBACK";  break;
+    case OE_Abort:    zLabel = "INSERT OR ABORT";     break;
+    case OE_Fail:     zLabel = "INSERT OR FAIL";      break;
+  }
+  sqlite3TreeViewPush(&pView, 0);
+  sqlite3TreeViewLine(pView, zLabel);
+  if( pWith ) n++;
+  if( pTabList ) n++;
+  if( pColumnList ) n++;
+  if( pSelect ) n++;
+  if( pExprList ) n++;
+  if( pUpsert ) n++;
+  if( pTrigger ) n++;
+  if( pWith ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewWith(pView, pWith, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTabList ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "INTO");
+    sqlite3TreeViewSrcList(pView, pTabList);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pColumnList ){
+    sqlite3TreeViewIdList(pView, pColumnList, (--n)>0, "COLUMNS");
+  }
+  if( pSelect ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "DATA-SOURCE");
+    sqlite3TreeViewSelect(pView, pSelect, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pExprList ){
+    sqlite3TreeViewExprList(pView, pExprList, (--n)>0, "VALUES");
+  }
+  if( pUpsert ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "UPSERT");
+    sqlite3TreeViewUpsert(pView, pUpsert, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTrigger ){
+    sqlite3TreeViewTrigger(pView, pTrigger, (--n)>0, 1);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* TREETRACE_ENABLED */
+
+#if TREETRACE_ENABLED
+/*
+** Generate a human-readable diagram of the data structure that go
+** into generating an UPDATE statement.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewUpdate(
+  const With *pWith,
+  const SrcList *pTabList,
+  const ExprList *pChanges,
+  const Expr *pWhere,
+  int onError,
+  const ExprList *pOrderBy,
+  const Expr *pLimit,
+  const Upsert *pUpsert,
+  const Trigger *pTrigger
+){
+  int n = 0;
+  TreeView *pView = 0;
+  const char *zLabel = "UPDATE";
+  switch( onError ){
+    case OE_Replace:  zLabel = "UPDATE OR REPLACE";   break;
+    case OE_Ignore:   zLabel = "UPDATE OR IGNORE";    break;
+    case OE_Rollback: zLabel = "UPDATE OR ROLLBACK";  break;
+    case OE_Abort:    zLabel = "UPDATE OR ABORT";     break;
+    case OE_Fail:     zLabel = "UPDATE OR FAIL";      break;
+  }
+  sqlite3TreeViewPush(&pView, 0);
+  sqlite3TreeViewLine(pView, zLabel);
+  if( pWith ) n++;
+  if( pTabList ) n++;
+  if( pChanges ) n++;
+  if( pWhere ) n++;
+  if( pOrderBy ) n++;
+  if( pLimit ) n++;
+  if( pUpsert ) n++;
+  if( pTrigger ) n++;
+  if( pWith ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewWith(pView, pWith, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTabList ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "FROM");
+    sqlite3TreeViewSrcList(pView, pTabList);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pChanges ){
+    sqlite3TreeViewExprList(pView, pChanges, (--n)>0, "SET");
+  }
+  if( pWhere ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "WHERE");
+    sqlite3TreeViewExpr(pView, pWhere, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pOrderBy ){
+    sqlite3TreeViewExprList(pView, pOrderBy, (--n)>0, "ORDER-BY");
+  }
+  if( pLimit ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "LIMIT");
+    sqlite3TreeViewExpr(pView, pLimit, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pUpsert ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "UPSERT");
+    sqlite3TreeViewUpsert(pView, pUpsert, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTrigger ){
+    sqlite3TreeViewTrigger(pView, pTrigger, (--n)>0, 1);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* TREETRACE_ENABLED */
+
+#ifndef SQLITE_OMIT_TRIGGER
+/*
+** Show a human-readable graph of a TriggerStep
+*/
+SQLITE_PRIVATE void sqlite3TreeViewTriggerStep(
+  TreeView *pView,
+  const TriggerStep *pStep,
+  u8 moreToFollow,
+  u8 showFullList
+){
+  int cnt = 0;
+  if( pStep==0 ) return;
+  sqlite3TreeViewPush(&pView,
+      moreToFollow || (showFullList && pStep->pNext!=0));
+  do{
+    if( cnt++ && pStep->pNext==0 ){
+      sqlite3TreeViewPop(&pView);
+      sqlite3TreeViewPush(&pView, 0);
+    }
+    sqlite3TreeViewLine(pView, "%s", pStep->zSpan ? pStep->zSpan : "RETURNING");
+  }while( showFullList && (pStep = pStep->pNext)!=0 );
+  sqlite3TreeViewPop(&pView);
+}
+
+/*
+** Show a human-readable graph of a Trigger
+*/
+SQLITE_PRIVATE void sqlite3TreeViewTrigger(
+  TreeView *pView,
+  const Trigger *pTrigger,
+  u8 moreToFollow,
+  u8 showFullList
+){
+  int cnt = 0;
+  if( pTrigger==0 ) return;
+  sqlite3TreeViewPush(&pView,
+     moreToFollow || (showFullList && pTrigger->pNext!=0));
+  do{
+    if( cnt++ && pTrigger->pNext==0 ){
+      sqlite3TreeViewPop(&pView);
+      sqlite3TreeViewPush(&pView, 0);
+    }
+    sqlite3TreeViewLine(pView, "TRIGGER %s", pTrigger->zName);
+    sqlite3TreeViewPush(&pView, 0);
+    sqlite3TreeViewTriggerStep(pView, pTrigger->step_list, 0, 1);
+    sqlite3TreeViewPop(&pView);
+  }while( showFullList && (pTrigger = pTrigger->pNext)!=0 );
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* SQLITE_OMIT_TRIGGER */
+
+
+/*
+** These simplified versions of the tree-view routines omit unnecessary
+** parameters.  These variants are intended to be used from a symbolic
+** debugger, such as "gdb", during interactive debugging sessions.
+**
+** This routines are given external linkage so that they will always be
+** accessible to the debugging, and to avoid warnings about unused
+** functions.  But these routines only exist in debugging builds, so they
+** do not contaminate the interface.
+**
+** See Also:
+**
+**     sqlite3ShowWhereTerm() in where.c
+*/
+SQLITE_PRIVATE void sqlite3ShowExpr(const Expr *p){ sqlite3TreeViewExpr(0,p,0); }
+SQLITE_PRIVATE void sqlite3ShowExprList(const ExprList *p){ sqlite3TreeViewExprList(0,p,0,0);}
+SQLITE_PRIVATE void sqlite3ShowIdList(const IdList *p){ sqlite3TreeViewIdList(0,p,0,0); }
+SQLITE_PRIVATE void sqlite3ShowSrcList(const SrcList *p){ sqlite3TreeViewSrcList(0,p); }
+SQLITE_PRIVATE void sqlite3ShowSelect(const Select *p){ sqlite3TreeViewSelect(0,p,0); }
+SQLITE_PRIVATE void sqlite3ShowWith(const With *p){ sqlite3TreeViewWith(0,p,0); }
+SQLITE_PRIVATE void sqlite3ShowUpsert(const Upsert *p){ sqlite3TreeViewUpsert(0,p,0); }
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE void sqlite3ShowTriggerStep(const TriggerStep *p){
+  sqlite3TreeViewTriggerStep(0,p,0,0);
+}
+SQLITE_PRIVATE void sqlite3ShowTriggerStepList(const TriggerStep *p){
+  sqlite3TreeViewTriggerStep(0,p,0,1);
+}
+SQLITE_PRIVATE void sqlite3ShowTrigger(const Trigger *p){ sqlite3TreeViewTrigger(0,p,0,0); }
+SQLITE_PRIVATE void sqlite3ShowTriggerList(const Trigger *p){ sqlite3TreeViewTrigger(0,p,0,1);}
+#endif
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE void sqlite3ShowWindow(const Window *p){ sqlite3TreeViewWindow(0,p,0); }
+SQLITE_PRIVATE void sqlite3ShowWinFunc(const Window *p){ sqlite3TreeViewWinFunc(0,p,0); }
+#endif
+
+#endif /* SQLITE_DEBUG */
+
+/************** End of treeview.c ********************************************/
+/************** Begin file random.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code to implement a pseudo-random number
+** generator (PRNG) for SQLite.
+**
+** Random numbers are used by some of the database backends in order
+** to generate random integer keys for tables or random filenames.
+*/
+/* #include "sqliteInt.h" */
+
+
+/* All threads share a single random number generator.
+** This structure is the current state of the generator.
+*/
+static SQLITE_WSD struct sqlite3PrngType {
+  u32 s[16];                 /* 64 bytes of chacha20 state */
+  u8 out[64];                /* Output bytes */
+  u8 n;                      /* Output bytes remaining */
+} sqlite3Prng;
+
+
+/* The RFC-7539 ChaCha20 block function
+*/
+#define ROTL(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
+#define QR(a, b, c, d) ( \
+    a += b, d ^= a, d = ROTL(d,16), \
+    c += d, b ^= c, b = ROTL(b,12), \
+    a += b, d ^= a, d = ROTL(d, 8), \
+    c += d, b ^= c, b = ROTL(b, 7))
+static void chacha_block(u32 *out, const u32 *in){
+  int i;
+  u32 x[16];
+  memcpy(x, in, 64);
+  for(i=0; i<10; i++){
+    QR(x[0], x[4], x[ 8], x[12]);
+    QR(x[1], x[5], x[ 9], x[13]);
+    QR(x[2], x[6], x[10], x[14]);
+    QR(x[3], x[7], x[11], x[15]);
+    QR(x[0], x[5], x[10], x[15]);
+    QR(x[1], x[6], x[11], x[12]);
+    QR(x[2], x[7], x[ 8], x[13]);
+    QR(x[3], x[4], x[ 9], x[14]);
+  }
+  for(i=0; i<16; i++) out[i] = x[i]+in[i];
+}
+
+/*
+** Return N random bytes.
+*/
+SQLITE_API void sqlite3_randomness(int N, void *pBuf){
+  unsigned char *zBuf = pBuf;
+
+  /* The "wsdPrng" macro will resolve to the pseudo-random number generator
+  ** state vector.  If writable static data is unsupported on the target,
+  ** we have to locate the state vector at run-time.  In the more common
+  ** case where writable static data is supported, wsdPrng can refer directly
+  ** to the "sqlite3Prng" state vector declared above.
+  */
+#ifdef SQLITE_OMIT_WSD
+  struct sqlite3PrngType *p = &GLOBAL(struct sqlite3PrngType, sqlite3Prng);
+# define wsdPrng p[0]
+#else
+# define wsdPrng sqlite3Prng
+#endif
+
+#if SQLITE_THREADSAFE
+  sqlite3_mutex *mutex;
+#endif
+
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return;
+#endif
+
+#if SQLITE_THREADSAFE
+  mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_PRNG);
+#endif
+
+  sqlite3_mutex_enter(mutex);
+  if( N<=0 || pBuf==0 ){
+    wsdPrng.s[0] = 0;
+    sqlite3_mutex_leave(mutex);
+    return;
+  }
+
+  /* Initialize the state of the random number generator once,
+  ** the first time this routine is called.
+  */
+  if( wsdPrng.s[0]==0 ){
+    sqlite3_vfs *pVfs = sqlite3_vfs_find(0);
+    static const u32 chacha20_init[] = {
+      0x61707865, 0x3320646e, 0x79622d32, 0x6b206574
+    };
+    memcpy(&wsdPrng.s[0], chacha20_init, 16);
+    if( NEVER(pVfs==0) ){
+      memset(&wsdPrng.s[4], 0, 44);
+    }else{
+      sqlite3OsRandomness(pVfs, 44, (char*)&wsdPrng.s[4]);
+    }
+    wsdPrng.s[15] = wsdPrng.s[12];
+    wsdPrng.s[12] = 0;
+    wsdPrng.n = 0;
+  }
+
+  assert( N>0 );
+  while( 1 /* exit by break */ ){
+    if( N<=wsdPrng.n ){
+      memcpy(zBuf, &wsdPrng.out[wsdPrng.n-N], N);
+      wsdPrng.n -= N;
+      break;
+    }
+    if( wsdPrng.n>0 ){
+      memcpy(zBuf, wsdPrng.out, wsdPrng.n);
+      N -= wsdPrng.n;
+      zBuf += wsdPrng.n;
+    }
+    wsdPrng.s[12]++;
+    chacha_block((u32*)wsdPrng.out, wsdPrng.s);
+    wsdPrng.n = 64;
+  }
+  sqlite3_mutex_leave(mutex);
+}
+
+#ifndef SQLITE_UNTESTABLE
+/*
+** For testing purposes, we sometimes want to preserve the state of
+** PRNG and restore the PRNG to its saved state at a later time, or
+** to reset the PRNG to its initial state.  These routines accomplish
+** those tasks.
+**
+** The sqlite3_test_control() interface calls these routines to
+** control the PRNG.
+*/
+static SQLITE_WSD struct sqlite3PrngType sqlite3SavedPrng;
+SQLITE_PRIVATE void sqlite3PrngSaveState(void){
+  memcpy(
+    &GLOBAL(struct sqlite3PrngType, sqlite3SavedPrng),
+    &GLOBAL(struct sqlite3PrngType, sqlite3Prng),
+    sizeof(sqlite3Prng)
+  );
+}
+SQLITE_PRIVATE void sqlite3PrngRestoreState(void){
+  memcpy(
+    &GLOBAL(struct sqlite3PrngType, sqlite3Prng),
+    &GLOBAL(struct sqlite3PrngType, sqlite3SavedPrng),
+    sizeof(sqlite3Prng)
+  );
+}
+#endif /* SQLITE_UNTESTABLE */
+
+/************** End of random.c **********************************************/
+/************** Begin file threads.c *****************************************/
+/*
+** 2012 July 21
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file presents a simple cross-platform threading interface for
+** use internally by SQLite.
+**
+** A "thread" can be created using sqlite3ThreadCreate().  This thread
+** runs independently of its creator until it is joined using
+** sqlite3ThreadJoin(), at which point it terminates.
+**
+** Threads do not have to be real.  It could be that the work of the
+** "thread" is done by the main thread at either the sqlite3ThreadCreate()
+** or sqlite3ThreadJoin() call.  This is, in fact, what happens in
+** single threaded systems.  Nothing in SQLite requires multiple threads.
+** This interface exists so that applications that want to take advantage
+** of multiple cores can do so, while also allowing applications to stay
+** single-threaded if desired.
+*/
+/* #include "sqliteInt.h" */
+#if SQLITE_OS_WIN
+/* #  include "os_win.h" */
+#endif
+
+#if SQLITE_MAX_WORKER_THREADS>0
+
+/********************************* Unix Pthreads ****************************/
+#if SQLITE_OS_UNIX && defined(SQLITE_MUTEX_PTHREADS) && SQLITE_THREADSAFE>0
+
+#define SQLITE_THREADS_IMPLEMENTED 1  /* Prevent the single-thread code below */
+/* #include <pthread.h> */
+
+/* A running thread */
+struct SQLiteThread {
+  pthread_t tid;                 /* Thread ID */
+  int done;                      /* Set to true when thread finishes */
+  void *pOut;                    /* Result returned by the thread */
+  void *(*xTask)(void*);         /* The thread routine */
+  void *pIn;                     /* Argument to the thread */
+};
+
+/* Create a new thread */
+SQLITE_PRIVATE int sqlite3ThreadCreate(
+  SQLiteThread **ppThread,  /* OUT: Write the thread object here */
+  void *(*xTask)(void*),    /* Routine to run in a separate thread */
+  void *pIn                 /* Argument passed into xTask() */
+){
+  SQLiteThread *p;
+  int rc;
+
+  assert( ppThread!=0 );
+  assert( xTask!=0 );
+  /* This routine is never used in single-threaded mode */
+  assert( sqlite3GlobalConfig.bCoreMutex!=0 );
+
+  *ppThread = 0;
+  p = sqlite3Malloc(sizeof(*p));
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  memset(p, 0, sizeof(*p));
+  p->xTask = xTask;
+  p->pIn = pIn;
+  /* If the SQLITE_TESTCTRL_FAULT_INSTALL callback is registered to a
+  ** function that returns SQLITE_ERROR when passed the argument 200, that
+  ** forces worker threads to run sequentially and deterministically
+  ** for testing purposes. */
+  if( sqlite3FaultSim(200) ){
+    rc = 1;
+  }else{
+    rc = pthread_create(&p->tid, 0, xTask, pIn);
+  }
+  if( rc ){
+    p->done = 1;
+    p->pOut = xTask(pIn);
+  }
+  *ppThread = p;
+  return SQLITE_OK;
+}
+
+/* Get the results of the thread */
+SQLITE_PRIVATE int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){
+  int rc;
+
+  assert( ppOut!=0 );
+  if( NEVER(p==0) ) return SQLITE_NOMEM_BKPT;
+  if( p->done ){
+    *ppOut = p->pOut;
+    rc = SQLITE_OK;
+  }else{
+    rc = pthread_join(p->tid, ppOut) ? SQLITE_ERROR : SQLITE_OK;
+  }
+  sqlite3_free(p);
+  return rc;
+}
+
+#endif /* SQLITE_OS_UNIX && defined(SQLITE_MUTEX_PTHREADS) */
+/******************************** End Unix Pthreads *************************/
+
+
+/********************************* Win32 Threads ****************************/
+#if SQLITE_OS_WIN_THREADS
+
+#define SQLITE_THREADS_IMPLEMENTED 1  /* Prevent the single-thread code below */
+#include <process.h>
+
+/* A running thread */
+struct SQLiteThread {
+  void *tid;               /* The thread handle */
+  unsigned id;             /* The thread identifier */
+  void *(*xTask)(void*);   /* The routine to run as a thread */
+  void *pIn;               /* Argument to xTask */
+  void *pResult;           /* Result of xTask */
+};
+
+/* Thread procedure Win32 compatibility shim */
+static unsigned __stdcall sqlite3ThreadProc(
+  void *pArg  /* IN: Pointer to the SQLiteThread structure */
+){
+  SQLiteThread *p = (SQLiteThread *)pArg;
+
+  assert( p!=0 );
+#if 0
+  /*
+  ** This assert appears to trigger spuriously on certain
+  ** versions of Windows, possibly due to _beginthreadex()
+  ** and/or CreateThread() not fully setting their thread
+  ** ID parameter before starting the thread.
+  */
+  assert( p->id==GetCurrentThreadId() );
+#endif
+  assert( p->xTask!=0 );
+  p->pResult = p->xTask(p->pIn);
+
+  _endthreadex(0);
+  return 0; /* NOT REACHED */
+}
+
+/* Create a new thread */
+SQLITE_PRIVATE int sqlite3ThreadCreate(
+  SQLiteThread **ppThread,  /* OUT: Write the thread object here */
+  void *(*xTask)(void*),    /* Routine to run in a separate thread */
+  void *pIn                 /* Argument passed into xTask() */
+){
+  SQLiteThread *p;
+
+  assert( ppThread!=0 );
+  assert( xTask!=0 );
+  *ppThread = 0;
+  p = sqlite3Malloc(sizeof(*p));
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  /* If the SQLITE_TESTCTRL_FAULT_INSTALL callback is registered to a
+  ** function that returns SQLITE_ERROR when passed the argument 200, that
+  ** forces worker threads to run sequentially and deterministically
+  ** (via the sqlite3FaultSim() term of the conditional) for testing
+  ** purposes. */
+  if( sqlite3GlobalConfig.bCoreMutex==0 || sqlite3FaultSim(200) ){
+    memset(p, 0, sizeof(*p));
+  }else{
+    p->xTask = xTask;
+    p->pIn = pIn;
+    p->tid = (void*)_beginthreadex(0, 0, sqlite3ThreadProc, p, 0, &p->id);
+    if( p->tid==0 ){
+      memset(p, 0, sizeof(*p));
+    }
+  }
+  if( p->xTask==0 ){
+    p->id = GetCurrentThreadId();
+    p->pResult = xTask(pIn);
+  }
+  *ppThread = p;
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE DWORD sqlite3Win32Wait(HANDLE hObject); /* os_win.c */
+
+/* Get the results of the thread */
+SQLITE_PRIVATE int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){
+  DWORD rc;
+  BOOL bRc;
+
+  assert( ppOut!=0 );
+  if( NEVER(p==0) ) return SQLITE_NOMEM_BKPT;
+  if( p->xTask==0 ){
+    /* assert( p->id==GetCurrentThreadId() ); */
+    rc = WAIT_OBJECT_0;
+    assert( p->tid==0 );
+  }else{
+    assert( p->id!=0 && p->id!=GetCurrentThreadId() );
+    rc = sqlite3Win32Wait((HANDLE)p->tid);
+    assert( rc!=WAIT_IO_COMPLETION );
+    bRc = CloseHandle((HANDLE)p->tid);
+    assert( bRc );
+  }
+  if( rc==WAIT_OBJECT_0 ) *ppOut = p->pResult;
+  sqlite3_free(p);
+  return (rc==WAIT_OBJECT_0) ? SQLITE_OK : SQLITE_ERROR;
+}
+
+#endif /* SQLITE_OS_WIN_THREADS */
+/******************************** End Win32 Threads *************************/
+
+
+/********************************* Single-Threaded **************************/
+#ifndef SQLITE_THREADS_IMPLEMENTED
+/*
+** This implementation does not actually create a new thread.  It does the
+** work of the thread in the main thread, when either the thread is created
+** or when it is joined
+*/
+
+/* A running thread */
+struct SQLiteThread {
+  void *(*xTask)(void*);   /* The routine to run as a thread */
+  void *pIn;               /* Argument to xTask */
+  void *pResult;           /* Result of xTask */
+};
+
+/* Create a new thread */
+SQLITE_PRIVATE int sqlite3ThreadCreate(
+  SQLiteThread **ppThread,  /* OUT: Write the thread object here */
+  void *(*xTask)(void*),    /* Routine to run in a separate thread */
+  void *pIn                 /* Argument passed into xTask() */
+){
+  SQLiteThread *p;
+
+  assert( ppThread!=0 );
+  assert( xTask!=0 );
+  *ppThread = 0;
+  p = sqlite3Malloc(sizeof(*p));
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  if( (SQLITE_PTR_TO_INT(p)/17)&1 ){
+    p->xTask = xTask;
+    p->pIn = pIn;
+  }else{
+    p->xTask = 0;
+    p->pResult = xTask(pIn);
+  }
+  *ppThread = p;
+  return SQLITE_OK;
+}
+
+/* Get the results of the thread */
+SQLITE_PRIVATE int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){
+
+  assert( ppOut!=0 );
+  if( NEVER(p==0) ) return SQLITE_NOMEM_BKPT;
+  if( p->xTask ){
+    *ppOut = p->xTask(p->pIn);
+  }else{
+    *ppOut = p->pResult;
+  }
+  sqlite3_free(p);
+
+#if defined(SQLITE_TEST)
+  {
+    void *pTstAlloc = sqlite3Malloc(10);
+    if (!pTstAlloc) return SQLITE_NOMEM_BKPT;
+    sqlite3_free(pTstAlloc);
+  }
+#endif
+
+  return SQLITE_OK;
+}
+
+#endif /* !defined(SQLITE_THREADS_IMPLEMENTED) */
+/****************************** End Single-Threaded *************************/
+#endif /* SQLITE_MAX_WORKER_THREADS>0 */
+
+/************** End of threads.c *********************************************/
+/************** Begin file utf.c *********************************************/
+/*
+** 2004 April 13
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used to translate between UTF-8,
+** UTF-16, UTF-16BE, and UTF-16LE.
+**
+** Notes on UTF-8:
+**
+**   Byte-0    Byte-1    Byte-2    Byte-3    Value
+**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
+**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
+**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx
+**  11110uuu  10uuzzzz  10yyyyyy  10xxxxxx   000uuuuu zzzzyyyy yyxxxxxx
+**
+**
+** Notes on UTF-16:  (with wwww+1==uuuuu)
+**
+**      Word-0               Word-1          Value
+**  110110ww wwzzzzyy   110111yy yyxxxxxx    000uuuuu zzzzyyyy yyxxxxxx
+**  zzzzyyyy yyxxxxxx                        00000000 zzzzyyyy yyxxxxxx
+**
+**
+** BOM or Byte Order Mark:
+**     0xff 0xfe   little-endian utf-16 follows
+**     0xfe 0xff   big-endian utf-16 follows
+**
+*/
+/* #include "sqliteInt.h" */
+/* #include <assert.h> */
+/* #include "vdbeInt.h" */
+
+#if !defined(SQLITE_AMALGAMATION) && SQLITE_BYTEORDER==0
+/*
+** The following constant value is used by the SQLITE_BIGENDIAN and
+** SQLITE_LITTLEENDIAN macros.
+*/
+SQLITE_PRIVATE const int sqlite3one = 1;
+#endif /* SQLITE_AMALGAMATION && SQLITE_BYTEORDER==0 */
+
+/*
+** This lookup table is used to help decode the first byte of
+** a multi-byte UTF8 character.
+*/
+static const unsigned char sqlite3Utf8Trans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+
+#define WRITE_UTF8(zOut, c) {                          \
+  if( c<0x00080 ){                                     \
+    *zOut++ = (u8)(c&0xFF);                            \
+  }                                                    \
+  else if( c<0x00800 ){                                \
+    *zOut++ = 0xC0 + (u8)((c>>6)&0x1F);                \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+  else if( c<0x10000 ){                                \
+    *zOut++ = 0xE0 + (u8)((c>>12)&0x0F);               \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }else{                                               \
+    *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);             \
+    *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);             \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+}
+
+#define WRITE_UTF16LE(zOut, c) {                                    \
+  if( c<=0xFFFF ){                                                  \
+    *zOut++ = (u8)(c&0x00FF);                                       \
+    *zOut++ = (u8)((c>>8)&0x00FF);                                  \
+  }else{                                                            \
+    *zOut++ = (u8)(((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \
+    *zOut++ = (u8)(0x00D8 + (((c-0x10000)>>18)&0x03));              \
+    *zOut++ = (u8)(c&0x00FF);                                       \
+    *zOut++ = (u8)(0x00DC + ((c>>8)&0x03));                         \
+  }                                                                 \
+}
+
+#define WRITE_UTF16BE(zOut, c) {                                    \
+  if( c<=0xFFFF ){                                                  \
+    *zOut++ = (u8)((c>>8)&0x00FF);                                  \
+    *zOut++ = (u8)(c&0x00FF);                                       \
+  }else{                                                            \
+    *zOut++ = (u8)(0x00D8 + (((c-0x10000)>>18)&0x03));              \
+    *zOut++ = (u8)(((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \
+    *zOut++ = (u8)(0x00DC + ((c>>8)&0x03));                         \
+    *zOut++ = (u8)(c&0x00FF);                                       \
+  }                                                                 \
+}
+
+/*
+** Translate a single UTF-8 character.  Return the unicode value.
+**
+** During translation, assume that the byte that zTerm points
+** is a 0x00.
+**
+** Write a pointer to the next unread byte back into *pzNext.
+**
+** Notes On Invalid UTF-8:
+**
+**  *  This routine never allows a 7-bit character (0x00 through 0x7f) to
+**     be encoded as a multi-byte character.  Any multi-byte character that
+**     attempts to encode a value between 0x00 and 0x7f is rendered as 0xfffd.
+**
+**  *  This routine never allows a UTF16 surrogate value to be encoded.
+**     If a multi-byte character attempts to encode a value between
+**     0xd800 and 0xe000 then it is rendered as 0xfffd.
+**
+**  *  Bytes in the range of 0x80 through 0xbf which occur as the first
+**     byte of a character are interpreted as single-byte characters
+**     and rendered as themselves even though they are technically
+**     invalid characters.
+**
+**  *  This routine accepts over-length UTF8 encodings
+**     for unicode values 0x80 and greater.  It does not change over-length
+**     encodings to 0xfffd as some systems recommend.
+*/
+#define READ_UTF8(zIn, zTerm, c)                           \
+  c = *(zIn++);                                            \
+  if( c>=0xc0 ){                                           \
+    c = sqlite3Utf8Trans1[c-0xc0];                         \
+    while( zIn<zTerm && (*zIn & 0xc0)==0x80 ){             \
+      c = (c<<6) + (0x3f & *(zIn++));                      \
+    }                                                      \
+    if( c<0x80                                             \
+        || (c&0xFFFFF800)==0xD800                          \
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }        \
+  }
+SQLITE_PRIVATE u32 sqlite3Utf8Read(
+  const unsigned char **pz    /* Pointer to string from which to read char */
+){
+  unsigned int c;
+
+  /* Same as READ_UTF8() above but without the zTerm parameter.
+  ** For this routine, we assume the UTF8 string is always zero-terminated.
+  */
+  c = *((*pz)++);
+  if( c>=0xc0 ){
+    c = sqlite3Utf8Trans1[c-0xc0];
+    while( (*(*pz) & 0xc0)==0x80 ){
+      c = (c<<6) + (0x3f & *((*pz)++));
+    }
+    if( c<0x80
+        || (c&0xFFFFF800)==0xD800
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }
+  }
+  return c;
+}
+
+/*
+** Read a single UTF8 character out of buffer z[], but reading no
+** more than n characters from the buffer.  z[] is not zero-terminated.
+**
+** Return the number of bytes used to construct the character.
+**
+** Invalid UTF8 might generate a strange result.  No effort is made
+** to detect invalid UTF8.
+**
+** At most 4 bytes will be read out of z[].  The return value will always
+** be between 1 and 4.
+*/
+SQLITE_PRIVATE int sqlite3Utf8ReadLimited(
+  const u8 *z,
+  int n,
+  u32 *piOut
+){
+  u32 c;
+  int i = 1;
+  assert( n>0 );
+  c = z[0];
+  if( c>=0xc0 ){
+    c = sqlite3Utf8Trans1[c-0xc0];
+    if( n>4 ) n = 4;
+    while( i<n && (z[i] & 0xc0)==0x80 ){
+      c = (c<<6) + (0x3f & z[i]);
+      i++;
+    }
+  }
+  *piOut = c;
+  return i;
+}
+
+
+/*
+** If the TRANSLATE_TRACE macro is defined, the value of each Mem is
+** printed on stderr on the way into and out of sqlite3VdbeMemTranslate().
+*/
+/* #define TRANSLATE_TRACE 1 */
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** This routine transforms the internal text encoding used by pMem to
+** desiredEnc. It is an error if the string is already of the desired
+** encoding, or if *pMem does not contain a string value.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){
+  sqlite3_int64 len;          /* Maximum length of output string in bytes */
+  unsigned char *zOut;        /* Output buffer */
+  unsigned char *zIn;         /* Input iterator */
+  unsigned char *zTerm;       /* End of input */
+  unsigned char *z;           /* Output iterator */
+  unsigned int c;
+
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( pMem->flags&MEM_Str );
+  assert( pMem->enc!=desiredEnc );
+  assert( pMem->enc!=0 );
+  assert( pMem->n>=0 );
+
+#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
+  {
+    StrAccum acc;
+    char zBuf[1000];
+    sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+    sqlite3VdbeMemPrettyPrint(pMem, &acc);
+    fprintf(stderr, "INPUT:  %s\n", sqlite3StrAccumFinish(&acc));
+  }
+#endif
+
+  /* If the translation is between UTF-16 little and big endian, then
+  ** all that is required is to swap the byte order. This case is handled
+  ** differently from the others.
+  */
+  if( pMem->enc!=SQLITE_UTF8 && desiredEnc!=SQLITE_UTF8 ){
+    u8 temp;
+    int rc;
+    rc = sqlite3VdbeMemMakeWriteable(pMem);
+    if( rc!=SQLITE_OK ){
+      assert( rc==SQLITE_NOMEM );
+      return SQLITE_NOMEM_BKPT;
+    }
+    zIn = (u8*)pMem->z;
+    zTerm = &zIn[pMem->n&~1];
+    while( zIn<zTerm ){
+      temp = *zIn;
+      *zIn = *(zIn+1);
+      zIn++;
+      *zIn++ = temp;
+    }
+    pMem->enc = desiredEnc;
+    goto translate_out;
+  }
+
+  /* Set len to the maximum number of bytes required in the output buffer. */
+  if( desiredEnc==SQLITE_UTF8 ){
+    /* When converting from UTF-16, the maximum growth results from
+    ** translating a 2-byte character to a 4-byte UTF-8 character.
+    ** A single byte is required for the output string
+    ** nul-terminator.
+    */
+    pMem->n &= ~1;
+    len = 2 * (sqlite3_int64)pMem->n + 1;
+  }else{
+    /* When converting from UTF-8 to UTF-16 the maximum growth is caused
+    ** when a 1-byte UTF-8 character is translated into a 2-byte UTF-16
+    ** character. Two bytes are required in the output buffer for the
+    ** nul-terminator.
+    */
+    len = 2 * (sqlite3_int64)pMem->n + 2;
+  }
+
+  /* Set zIn to point at the start of the input buffer and zTerm to point 1
+  ** byte past the end.
+  **
+  ** Variable zOut is set to point at the output buffer, space obtained
+  ** from sqlite3_malloc().
+  */
+  zIn = (u8*)pMem->z;
+  zTerm = &zIn[pMem->n];
+  zOut = sqlite3DbMallocRaw(pMem->db, len);
+  if( !zOut ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  z = zOut;
+
+  if( pMem->enc==SQLITE_UTF8 ){
+    if( desiredEnc==SQLITE_UTF16LE ){
+      /* UTF-8 -> UTF-16 Little-endian */
+      while( zIn<zTerm ){
+        READ_UTF8(zIn, zTerm, c);
+        WRITE_UTF16LE(z, c);
+      }
+    }else{
+      assert( desiredEnc==SQLITE_UTF16BE );
+      /* UTF-8 -> UTF-16 Big-endian */
+      while( zIn<zTerm ){
+        READ_UTF8(zIn, zTerm, c);
+        WRITE_UTF16BE(z, c);
+      }
+    }
+    pMem->n = (int)(z - zOut);
+    *z++ = 0;
+  }else{
+    assert( desiredEnc==SQLITE_UTF8 );
+    if( pMem->enc==SQLITE_UTF16LE ){
+      /* UTF-16 Little-endian -> UTF-8 */
+      while( zIn<zTerm ){
+        c = *(zIn++);
+        c += (*(zIn++))<<8;
+        if( c>=0xd800 && c<0xe000 ){
+#ifdef SQLITE_REPLACE_INVALID_UTF
+          if( c>=0xdc00 || zIn>=zTerm ){
+            c = 0xfffd;
+          }else{
+            int c2 = *(zIn++);
+            c2 += (*(zIn++))<<8;
+            if( c2<0xdc00 || c2>=0xe000 ){
+              zIn -= 2;
+              c = 0xfffd;
+            }else{
+              c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
+            }
+          }
+#else
+          if( zIn<zTerm ){
+            int c2 = (*zIn++);
+            c2 += ((*zIn++)<<8);
+            c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);
+          }
+#endif
+        }
+        WRITE_UTF8(z, c);
+      }
+    }else{
+      /* UTF-16 Big-endian -> UTF-8 */
+      while( zIn<zTerm ){
+        c = (*(zIn++))<<8;
+        c += *(zIn++);
+        if( c>=0xd800 && c<0xe000 ){
+#ifdef SQLITE_REPLACE_INVALID_UTF
+          if( c>=0xdc00 || zIn>=zTerm ){
+            c = 0xfffd;
+          }else{
+            int c2 = (*(zIn++))<<8;
+            c2 += *(zIn++);
+            if( c2<0xdc00 || c2>=0xe000 ){
+              zIn -= 2;
+              c = 0xfffd;
+            }else{
+              c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
+            }
+          }
+#else
+          if( zIn<zTerm ){
+            int c2 = ((*zIn++)<<8);
+            c2 += (*zIn++);
+            c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);
+          }
+#endif
+        }
+        WRITE_UTF8(z, c);
+      }
+    }
+    pMem->n = (int)(z - zOut);
+  }
+  *z = 0;
+  assert( (pMem->n+(desiredEnc==SQLITE_UTF8?1:2))<=len );
+
+  c = MEM_Str|MEM_Term|(pMem->flags&(MEM_AffMask|MEM_Subtype));
+  sqlite3VdbeMemRelease(pMem);
+  pMem->flags = c;
+  pMem->enc = desiredEnc;
+  pMem->z = (char*)zOut;
+  pMem->zMalloc = pMem->z;
+  pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->z);
+
+translate_out:
+#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
+  {
+    StrAccum acc;
+    char zBuf[1000];
+    sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+    sqlite3VdbeMemPrettyPrint(pMem, &acc);
+    fprintf(stderr, "OUTPUT: %s\n", sqlite3StrAccumFinish(&acc));
+  }
+#endif
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** This routine checks for a byte-order mark at the beginning of the
+** UTF-16 string stored in *pMem. If one is present, it is removed and
+** the encoding of the Mem adjusted. This routine does not do any
+** byte-swapping, it just sets Mem.enc appropriately.
+**
+** The allocation (static, dynamic etc.) and encoding of the Mem may be
+** changed by this function.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemHandleBom(Mem *pMem){
+  int rc = SQLITE_OK;
+  u8 bom = 0;
+
+  assert( pMem->n>=0 );
+  if( pMem->n>1 ){
+    u8 b1 = *(u8 *)pMem->z;
+    u8 b2 = *(((u8 *)pMem->z) + 1);
+    if( b1==0xFE && b2==0xFF ){
+      bom = SQLITE_UTF16BE;
+    }
+    if( b1==0xFF && b2==0xFE ){
+      bom = SQLITE_UTF16LE;
+    }
+  }
+
+  if( bom ){
+    rc = sqlite3VdbeMemMakeWriteable(pMem);
+    if( rc==SQLITE_OK ){
+      pMem->n -= 2;
+      memmove(pMem->z, &pMem->z[2], pMem->n);
+      pMem->z[pMem->n] = '\0';
+      pMem->z[pMem->n+1] = '\0';
+      pMem->flags |= MEM_Term;
+      pMem->enc = bom;
+    }
+  }
+  return rc;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** pZ is a UTF-8 encoded unicode string. If nByte is less than zero,
+** return the number of unicode characters in pZ up to (but not including)
+** the first 0x00 byte. If nByte is not less than zero, return the
+** number of unicode characters in the first nByte of pZ (or up to
+** the first 0x00, whichever comes first).
+*/
+SQLITE_PRIVATE int sqlite3Utf8CharLen(const char *zIn, int nByte){
+  int r = 0;
+  const u8 *z = (const u8*)zIn;
+  const u8 *zTerm;
+  if( nByte>=0 ){
+    zTerm = &z[nByte];
+  }else{
+    zTerm = (const u8*)(-1);
+  }
+  assert( z<=zTerm );
+  while( *z!=0 && z<zTerm ){
+    SQLITE_SKIP_UTF8(z);
+    r++;
+  }
+  return r;
+}
+
+/* This test function is not currently used by the automated test-suite.
+** Hence it is only available in debug builds.
+*/
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+/*
+** Translate UTF-8 to UTF-8.
+**
+** This has the effect of making sure that the string is well-formed
+** UTF-8.  Miscoded characters are removed.
+**
+** The translation is done in-place and aborted if the output
+** overruns the input.
+*/
+SQLITE_PRIVATE int sqlite3Utf8To8(unsigned char *zIn){
+  unsigned char *zOut = zIn;
+  unsigned char *zStart = zIn;
+  u32 c;
+
+  while( zIn[0] && zOut<=zIn ){
+    c = sqlite3Utf8Read((const u8**)&zIn);
+    if( c!=0xfffd ){
+      WRITE_UTF8(zOut, c);
+    }
+  }
+  *zOut = 0;
+  return (int)(zOut - zStart);
+}
+#endif
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Convert a UTF-16 string in the native encoding into a UTF-8 string.
+** Memory to hold the UTF-8 string is obtained from sqlite3_malloc and must
+** be freed by the calling function.
+**
+** NULL is returned if there is an allocation error.
+*/
+SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *db, const void *z, int nByte, u8 enc){
+  Mem m;
+  memset(&m, 0, sizeof(m));
+  m.db = db;
+  sqlite3VdbeMemSetStr(&m, z, nByte, enc, SQLITE_STATIC);
+  sqlite3VdbeChangeEncoding(&m, SQLITE_UTF8);
+  if( db->mallocFailed ){
+    sqlite3VdbeMemRelease(&m);
+    m.z = 0;
+  }
+  assert( (m.flags & MEM_Term)!=0 || db->mallocFailed );
+  assert( (m.flags & MEM_Str)!=0 || db->mallocFailed );
+  assert( m.z || db->mallocFailed );
+  return m.z;
+}
+
+/*
+** zIn is a UTF-16 encoded unicode string at least nByte bytes long.
+** Return the number of bytes in the first nChar unicode characters
+** in pZ.  nChar must be non-negative.  Surrogate pairs count as a single
+** character.
+*/
+SQLITE_PRIVATE int sqlite3Utf16ByteLen(const void *zIn, int nByte, int nChar){
+  int c;
+  unsigned char const *z = zIn;
+  unsigned char const *zEnd = &z[nByte-1];
+  int n = 0;
+
+  if( SQLITE_UTF16NATIVE==SQLITE_UTF16LE ) z++;
+  while( n<nChar && ALWAYS(z<=zEnd) ){
+    c = z[0];
+    z += 2;
+    if( c>=0xd8 && c<0xdc && z<=zEnd && z[0]>=0xdc && z[0]<0xe0 ) z += 2;
+    n++;
+  }
+  return (int)(z-(unsigned char const *)zIn)
+              - (SQLITE_UTF16NATIVE==SQLITE_UTF16LE);
+}
+
+#if defined(SQLITE_TEST)
+/*
+** This routine is called from the TCL test function "translate_selftest".
+** It checks that the primitives for serializing and deserializing
+** characters in each encoding are inverses of each other.
+*/
+SQLITE_PRIVATE void sqlite3UtfSelfTest(void){
+  unsigned int i, t;
+  unsigned char zBuf[20];
+  unsigned char *z;
+  int n;
+  unsigned int c;
+
+  for(i=0; i<0x00110000; i++){
+    z = zBuf;
+    WRITE_UTF8(z, i);
+    n = (int)(z-zBuf);
+    assert( n>0 && n<=4 );
+    z[0] = 0;
+    z = zBuf;
+    c = sqlite3Utf8Read((const u8**)&z);
+    t = i;
+    if( i>=0xD800 && i<=0xDFFF ) t = 0xFFFD;
+    if( (i&0xFFFFFFFE)==0xFFFE ) t = 0xFFFD;
+    assert( c==t );
+    assert( (z-zBuf)==n );
+  }
+}
+#endif /* SQLITE_TEST */
+#endif /* SQLITE_OMIT_UTF16 */
+
+/************** End of utf.c *************************************************/
+/************** Begin file util.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Utility functions used throughout sqlite.
+**
+** This file contains functions for allocating memory, comparing
+** strings, and stuff like that.
+**
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdarg.h> */
+#ifndef SQLITE_OMIT_FLOATING_POINT
+#include <math.h>
+#endif
+
+/*
+** Calls to sqlite3FaultSim() are used to simulate a failure during testing,
+** or to bypass normal error detection during testing in order to let
+** execute proceed further downstream.
+**
+** In deployment, sqlite3FaultSim() *always* return SQLITE_OK (0).  The
+** sqlite3FaultSim() function only returns non-zero during testing.
+**
+** During testing, if the test harness has set a fault-sim callback using
+** a call to sqlite3_test_control(SQLITE_TESTCTRL_FAULT_INSTALL), then
+** each call to sqlite3FaultSim() is relayed to that application-supplied
+** callback and the integer return value form the application-supplied
+** callback is returned by sqlite3FaultSim().
+**
+** The integer argument to sqlite3FaultSim() is a code to identify which
+** sqlite3FaultSim() instance is being invoked. Each call to sqlite3FaultSim()
+** should have a unique code.  To prevent legacy testing applications from
+** breaking, the codes should not be changed or reused.
+*/
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE int sqlite3FaultSim(int iTest){
+  int (*xCallback)(int) = sqlite3GlobalConfig.xTestCallback;
+  return xCallback ? xCallback(iTest) : SQLITE_OK;
+}
+#endif
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Return true if the floating point value is Not a Number (NaN).
+**
+** Use the math library isnan() function if compiled with SQLITE_HAVE_ISNAN.
+** Otherwise, we have our own implementation that works on most systems.
+*/
+SQLITE_PRIVATE int sqlite3IsNaN(double x){
+  int rc;   /* The value return */
+#if !SQLITE_HAVE_ISNAN && !HAVE_ISNAN
+  u64 y;
+  memcpy(&y,&x,sizeof(y));
+  rc = IsNaN(y);
+#else
+  rc = isnan(x);
+#endif /* HAVE_ISNAN */
+  testcase( rc );
+  return rc;
+}
+#endif /* SQLITE_OMIT_FLOATING_POINT */
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Return true if the floating point value is NaN or +Inf or -Inf.
+*/
+SQLITE_PRIVATE int sqlite3IsOverflow(double x){
+  int rc;   /* The value return */
+  u64 y;
+  memcpy(&y,&x,sizeof(y));
+  rc = IsOvfl(y);
+  return rc;
+}
+#endif /* SQLITE_OMIT_FLOATING_POINT */
+
+/*
+** Compute a string length that is limited to what can be stored in
+** lower 30 bits of a 32-bit signed integer.
+**
+** The value returned will never be negative.  Nor will it ever be greater
+** than the actual length of the string.  For very long strings (greater
+** than 1GiB) the value returned might be less than the true string length.
+*/
+SQLITE_PRIVATE int sqlite3Strlen30(const char *z){
+  if( z==0 ) return 0;
+  return 0x3fffffff & (int)strlen(z);
+}
+
+/*
+** Return the declared type of a column.  Or return zDflt if the column
+** has no declared type.
+**
+** The column type is an extra string stored after the zero-terminator on
+** the column name if and only if the COLFLAG_HASTYPE flag is set.
+*/
+SQLITE_PRIVATE char *sqlite3ColumnType(Column *pCol, char *zDflt){
+  if( pCol->colFlags & COLFLAG_HASTYPE ){
+    return pCol->zCnName + strlen(pCol->zCnName) + 1;
+  }else if( pCol->eCType ){
+    assert( pCol->eCType<=SQLITE_N_STDTYPE );
+    return (char*)sqlite3StdType[pCol->eCType-1];
+  }else{
+    return zDflt;
+  }
+}
+
+/*
+** Helper function for sqlite3Error() - called rarely.  Broken out into
+** a separate routine to avoid unnecessary register saves on entry to
+** sqlite3Error().
+*/
+static SQLITE_NOINLINE void  sqlite3ErrorFinish(sqlite3 *db, int err_code){
+  if( db->pErr ) sqlite3ValueSetNull(db->pErr);
+  sqlite3SystemError(db, err_code);
+}
+
+/*
+** Set the current error code to err_code and clear any prior error message.
+** Also set iSysErrno (by calling sqlite3System) if the err_code indicates
+** that would be appropriate.
+*/
+SQLITE_PRIVATE void sqlite3Error(sqlite3 *db, int err_code){
+  assert( db!=0 );
+  db->errCode = err_code;
+  if( err_code || db->pErr ){
+    sqlite3ErrorFinish(db, err_code);
+  }else{
+    db->errByteOffset = -1;
+  }
+}
+
+/*
+** The equivalent of sqlite3Error(db, SQLITE_OK).  Clear the error state
+** and error message.
+*/
+SQLITE_PRIVATE void sqlite3ErrorClear(sqlite3 *db){
+  assert( db!=0 );
+  db->errCode = SQLITE_OK;
+  db->errByteOffset = -1;
+  if( db->pErr ) sqlite3ValueSetNull(db->pErr);
+}
+
+/*
+** Load the sqlite3.iSysErrno field if that is an appropriate thing
+** to do based on the SQLite error code in rc.
+*/
+SQLITE_PRIVATE void sqlite3SystemError(sqlite3 *db, int rc){
+  if( rc==SQLITE_IOERR_NOMEM ) return;
+#if defined(SQLITE_USE_SEH) && !defined(SQLITE_OMIT_WAL)
+  if( rc==SQLITE_IOERR_IN_PAGE ){
+    int ii;
+    int iErr;
+    sqlite3BtreeEnterAll(db);
+    for(ii=0; ii<db->nDb; ii++){
+      if( db->aDb[ii].pBt ){
+        iErr = sqlite3PagerWalSystemErrno(sqlite3BtreePager(db->aDb[ii].pBt));
+        if( iErr ){
+          db->iSysErrno = iErr;
+        }
+      }
+    }
+    sqlite3BtreeLeaveAll(db);
+    return;
+  }
+#endif
+  rc &= 0xff;
+  if( rc==SQLITE_CANTOPEN || rc==SQLITE_IOERR ){
+    db->iSysErrno = sqlite3OsGetLastError(db->pVfs);
+  }
+}
+
+/*
+** Set the most recent error code and error string for the sqlite
+** handle "db". The error code is set to "err_code".
+**
+** If it is not NULL, string zFormat specifies the format of the
+** error string.  zFormat and any string tokens that follow it are
+** assumed to be encoded in UTF-8.
+**
+** To clear the most recent error for sqlite handle "db", sqlite3Error
+** should be called with err_code set to SQLITE_OK and zFormat set
+** to NULL.
+*/
+SQLITE_PRIVATE void sqlite3ErrorWithMsg(sqlite3 *db, int err_code, const char *zFormat, ...){
+  assert( db!=0 );
+  db->errCode = err_code;
+  sqlite3SystemError(db, err_code);
+  if( zFormat==0 ){
+    sqlite3Error(db, err_code);
+  }else if( db->pErr || (db->pErr = sqlite3ValueNew(db))!=0 ){
+    char *z;
+    va_list ap;
+    va_start(ap, zFormat);
+    z = sqlite3VMPrintf(db, zFormat, ap);
+    va_end(ap);
+    sqlite3ValueSetStr(db->pErr, -1, z, SQLITE_UTF8, SQLITE_DYNAMIC);
+  }
+}
+
+/*
+** Check for interrupts and invoke progress callback.
+*/
+SQLITE_PRIVATE void sqlite3ProgressCheck(Parse *p){
+  sqlite3 *db = p->db;
+  if( AtomicLoad(&db->u1.isInterrupted) ){
+    p->nErr++;
+    p->rc = SQLITE_INTERRUPT;
+  }
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  if( db->xProgress ){
+    if( p->rc==SQLITE_INTERRUPT ){
+      p->nProgressSteps = 0;
+    }else if( (++p->nProgressSteps)>=db->nProgressOps ){
+      if( db->xProgress(db->pProgressArg) ){
+        p->nErr++;
+        p->rc = SQLITE_INTERRUPT;
+      }
+      p->nProgressSteps = 0;
+    }
+  }
+#endif
+}
+
+/*
+** Add an error message to pParse->zErrMsg and increment pParse->nErr.
+**
+** This function should be used to report any error that occurs while
+** compiling an SQL statement (i.e. within sqlite3_prepare()). The
+** last thing the sqlite3_prepare() function does is copy the error
+** stored by this function into the database handle using sqlite3Error().
+** Functions sqlite3Error() or sqlite3ErrorWithMsg() should be used
+** during statement execution (sqlite3_step() etc.).
+*/
+SQLITE_PRIVATE void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
+  char *zMsg;
+  va_list ap;
+  sqlite3 *db = pParse->db;
+  assert( db!=0 );
+  assert( db->pParse==pParse || db->pParse->pToplevel==pParse );
+  db->errByteOffset = -2;
+  va_start(ap, zFormat);
+  zMsg = sqlite3VMPrintf(db, zFormat, ap);
+  va_end(ap);
+  if( db->errByteOffset<-1 ) db->errByteOffset = -1;
+  if( db->suppressErr ){
+    sqlite3DbFree(db, zMsg);
+    if( db->mallocFailed ){
+      pParse->nErr++;
+      pParse->rc = SQLITE_NOMEM;
+    }
+  }else{
+    pParse->nErr++;
+    sqlite3DbFree(db, pParse->zErrMsg);
+    pParse->zErrMsg = zMsg;
+    pParse->rc = SQLITE_ERROR;
+    pParse->pWith = 0;
+  }
+}
+
+/*
+** If database connection db is currently parsing SQL, then transfer
+** error code errCode to that parser if the parser has not already
+** encountered some other kind of error.
+*/
+SQLITE_PRIVATE int sqlite3ErrorToParser(sqlite3 *db, int errCode){
+  Parse *pParse;
+  if( db==0 || (pParse = db->pParse)==0 ) return errCode;
+  pParse->rc = errCode;
+  pParse->nErr++;
+  return errCode;
+}
+
+/*
+** Convert an SQL-style quoted string into a normal string by removing
+** the quote characters.  The conversion is done in-place.  If the
+** input does not begin with a quote character, then this routine
+** is a no-op.
+**
+** The input string must be zero-terminated.  A new zero-terminator
+** is added to the dequoted string.
+**
+** The return value is -1 if no dequoting occurs or the length of the
+** dequoted string, exclusive of the zero terminator, if dequoting does
+** occur.
+**
+** 2002-02-14: This routine is extended to remove MS-Access style
+** brackets from around identifiers.  For example:  "[a-b-c]" becomes
+** "a-b-c".
+*/
+SQLITE_PRIVATE void sqlite3Dequote(char *z){
+  char quote;
+  int i, j;
+  if( z==0 ) return;
+  quote = z[0];
+  if( !sqlite3Isquote(quote) ) return;
+  if( quote=='[' ) quote = ']';
+  for(i=1, j=0;; i++){
+    assert( z[i] );
+    if( z[i]==quote ){
+      if( z[i+1]==quote ){
+        z[j++] = quote;
+        i++;
+      }else{
+        break;
+      }
+    }else{
+      z[j++] = z[i];
+    }
+  }
+  z[j] = 0;
+}
+SQLITE_PRIVATE void sqlite3DequoteExpr(Expr *p){
+  assert( !ExprHasProperty(p, EP_IntValue) );
+  assert( sqlite3Isquote(p->u.zToken[0]) );
+  p->flags |= p->u.zToken[0]=='"' ? EP_Quoted|EP_DblQuoted : EP_Quoted;
+  sqlite3Dequote(p->u.zToken);
+}
+
+/*
+** Expression p is a QNUMBER (quoted number). Dequote the value in p->u.zToken
+** and set the type to INTEGER or FLOAT. "Quoted" integers or floats are those
+** that contain '_' characters that must be removed before further processing.
+*/
+SQLITE_PRIVATE void sqlite3DequoteNumber(Parse *pParse, Expr *p){
+  assert( p!=0 || pParse->db->mallocFailed );
+  if( p ){
+    const char *pIn = p->u.zToken;
+    char *pOut = p->u.zToken;
+    int bHex = (pIn[0]=='0' && (pIn[1]=='x' || pIn[1]=='X'));
+    int iValue;
+    assert( p->op==TK_QNUMBER );
+    p->op = TK_INTEGER;
+    do {
+      if( *pIn!=SQLITE_DIGIT_SEPARATOR ){
+        *pOut++ = *pIn;
+        if( *pIn=='e' || *pIn=='E' || *pIn=='.' ) p->op = TK_FLOAT;
+      }else{
+        if( (bHex==0 && (!sqlite3Isdigit(pIn[-1]) || !sqlite3Isdigit(pIn[1])))
+         || (bHex==1 && (!sqlite3Isxdigit(pIn[-1]) || !sqlite3Isxdigit(pIn[1])))
+        ){
+          sqlite3ErrorMsg(pParse, "unrecognized token: \"%s\"", p->u.zToken);
+        }
+      }
+    }while( *pIn++ );
+    if( bHex ) p->op = TK_INTEGER;
+
+    /* tag-20240227-a: If after dequoting, the number is an integer that
+    ** fits in 32 bits, then it must be converted into EP_IntValue.  Other
+    ** parts of the code expect this.  See also tag-20240227-b. */
+    if( p->op==TK_INTEGER && sqlite3GetInt32(p->u.zToken, &iValue) ){
+      p->u.iValue = iValue;
+      p->flags |= EP_IntValue;
+    }
+  }
+}
+
+/*
+** If the input token p is quoted, try to adjust the token to remove
+** the quotes.  This is not always possible:
+**
+**     "abc"     ->   abc
+**     "ab""cd"  ->   (not possible because of the interior "")
+**
+** Remove the quotes if possible.  This is a optimization.  The overall
+** system should still return the correct answer even if this routine
+** is always a no-op.
+*/
+SQLITE_PRIVATE void sqlite3DequoteToken(Token *p){
+  unsigned int i;
+  if( p->n<2 ) return;
+  if( !sqlite3Isquote(p->z[0]) ) return;
+  for(i=1; i<p->n-1; i++){
+    if( sqlite3Isquote(p->z[i]) ) return;
+  }
+  p->n -= 2;
+  p->z++;
+}
+
+/*
+** Generate a Token object from a string
+*/
+SQLITE_PRIVATE void sqlite3TokenInit(Token *p, char *z){
+  p->z = z;
+  p->n = sqlite3Strlen30(z);
+}
+
+/* Convenient short-hand */
+#define UpperToLower sqlite3UpperToLower
+
+/*
+** Some systems have stricmp().  Others have strcasecmp().  Because
+** there is no consistency, we will define our own.
+**
+** IMPLEMENTATION-OF: R-30243-02494 The sqlite3_stricmp() and
+** sqlite3_strnicmp() APIs allow applications and extensions to compare
+** the contents of two buffers containing UTF-8 strings in a
+** case-independent fashion, using the same definition of "case
+** independence" that SQLite uses internally when comparing identifiers.
+*/
+SQLITE_API int sqlite3_stricmp(const char *zLeft, const char *zRight){
+  if( zLeft==0 ){
+    return zRight ? -1 : 0;
+  }else if( zRight==0 ){
+    return 1;
+  }
+  return sqlite3StrICmp(zLeft, zRight);
+}
+SQLITE_PRIVATE int sqlite3StrICmp(const char *zLeft, const char *zRight){
+  unsigned char *a, *b;
+  int c, x;
+  a = (unsigned char *)zLeft;
+  b = (unsigned char *)zRight;
+  for(;;){
+    c = *a;
+    x = *b;
+    if( c==x ){
+      if( c==0 ) break;
+    }else{
+      c = (int)UpperToLower[c] - (int)UpperToLower[x];
+      if( c ) break;
+    }
+    a++;
+    b++;
+  }
+  return c;
+}
+SQLITE_API int sqlite3_strnicmp(const char *zLeft, const char *zRight, int N){
+  register unsigned char *a, *b;
+  if( zLeft==0 ){
+    return zRight ? -1 : 0;
+  }else if( zRight==0 ){
+    return 1;
+  }
+  a = (unsigned char *)zLeft;
+  b = (unsigned char *)zRight;
+  while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
+  return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
+}
+
+/*
+** Compute an 8-bit hash on a string that is insensitive to case differences
+*/
+SQLITE_PRIVATE u8 sqlite3StrIHash(const char *z){
+  u8 h = 0;
+  if( z==0 ) return 0;
+  while( z[0] ){
+    h += UpperToLower[(unsigned char)z[0]];
+    z++;
+  }
+  return h;
+}
+
+/* Double-Double multiplication.  (x[0],x[1]) *= (y,yy)
+**
+** Reference:
+**   T. J. Dekker, "A Floating-Point Technique for Extending the
+**   Available Precision".  1971-07-26.
+*/
+static void dekkerMul2(volatile double *x, double y, double yy){
+  /*
+  ** The "volatile" keywords on parameter x[] and on local variables
+  ** below are needed force intermediate results to be truncated to
+  ** binary64 rather than be carried around in an extended-precision
+  ** format.  The truncation is necessary for the Dekker algorithm to
+  ** work.  Intel x86 floating point might omit the truncation without
+  ** the use of volatile.
+  */
+  volatile double tx, ty, p, q, c, cc;
+  double hx, hy;
+  u64 m;
+  memcpy(&m, (void*)&x[0], 8);
+  m &= 0xfffffffffc000000LL;
+  memcpy(&hx, &m, 8);
+  tx = x[0] - hx;
+  memcpy(&m, &y, 8);
+  m &= 0xfffffffffc000000LL;
+  memcpy(&hy, &m, 8);
+  ty = y - hy;
+  p = hx*hy;
+  q = hx*ty + tx*hy;
+  c = p+q;
+  cc = p - c + q + tx*ty;
+  cc = x[0]*yy + x[1]*y + cc;
+  x[0] = c + cc;
+  x[1] = c - x[0];
+  x[1] += cc;
+}
+
+/*
+** The string z[] is an text representation of a real number.
+** Convert this string to a double and write it into *pResult.
+**
+** The string z[] is length bytes in length (bytes, not characters) and
+** uses the encoding enc.  The string is not necessarily zero-terminated.
+**
+** Return TRUE if the result is a valid real number (or integer) and FALSE
+** if the string is empty or contains extraneous text.  More specifically
+** return
+**      1          =>  The input string is a pure integer
+**      2 or more  =>  The input has a decimal point or eNNN clause
+**      0 or less  =>  The input string is not a valid number
+**     -1          =>  Not a valid number, but has a valid prefix which
+**                     includes a decimal point and/or an eNNN clause
+**
+** Valid numbers are in one of these formats:
+**
+**    [+-]digits[E[+-]digits]
+**    [+-]digits.[digits][E[+-]digits]
+**    [+-].digits[E[+-]digits]
+**
+** Leading and trailing whitespace is ignored for the purpose of determining
+** validity.
+**
+** If some prefix of the input string is a valid number, this routine
+** returns FALSE but it still converts the prefix and writes the result
+** into *pResult.
+*/
+#if defined(_MSC_VER)
+#pragma warning(disable : 4756)
+#endif
+SQLITE_PRIVATE int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  int incr;
+  const char *zEnd;
+  /* sign * significand * (10 ^ (esign * exponent)) */
+  int sign = 1;    /* sign of significand */
+  u64 s = 0;       /* significand */
+  int d = 0;       /* adjust exponent for shifting decimal point */
+  int esign = 1;   /* sign of exponent */
+  int e = 0;       /* exponent */
+  int eValid = 1;  /* True exponent is either not used or is well-formed */
+  int nDigit = 0;  /* Number of digits processed */
+  int eType = 1;   /* 1: pure integer,  2+: fractional  -1 or less: bad UTF16 */
+  u64 s2;          /* round-tripped significand */
+  double rr[2];
+
+  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
+  *pResult = 0.0;   /* Default return value, in case of an error */
+  if( length==0 ) return 0;
+
+  if( enc==SQLITE_UTF8 ){
+    incr = 1;
+    zEnd = z + length;
+  }else{
+    int i;
+    incr = 2;
+    length &= ~1;
+    assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
+    testcase( enc==SQLITE_UTF16LE );
+    testcase( enc==SQLITE_UTF16BE );
+    for(i=3-enc; i<length && z[i]==0; i+=2){}
+    if( i<length ) eType = -100;
+    zEnd = &z[i^1];
+    z += (enc&1);
+  }
+
+  /* skip leading spaces */
+  while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
+  if( z>=zEnd ) return 0;
+
+  /* get sign of significand */
+  if( *z=='-' ){
+    sign = -1;
+    z+=incr;
+  }else if( *z=='+' ){
+    z+=incr;
+  }
+
+  /* copy max significant digits to significand */
+  while( z<zEnd && sqlite3Isdigit(*z) ){
+    s = s*10 + (*z - '0');
+    z+=incr; nDigit++;
+    if( s>=((LARGEST_UINT64-9)/10) ){
+      /* skip non-significant significand digits
+      ** (increase exponent by d to shift decimal left) */
+      while( z<zEnd && sqlite3Isdigit(*z) ){ z+=incr; d++; }
+    }
+  }
+  if( z>=zEnd ) goto do_atof_calc;
+
+  /* if decimal point is present */
+  if( *z=='.' ){
+    z+=incr;
+    eType++;
+    /* copy digits from after decimal to significand
+    ** (decrease exponent by d to shift decimal right) */
+    while( z<zEnd && sqlite3Isdigit(*z) ){
+      if( s<((LARGEST_UINT64-9)/10) ){
+        s = s*10 + (*z - '0');
+        d--;
+        nDigit++;
+      }
+      z+=incr;
+    }
+  }
+  if( z>=zEnd ) goto do_atof_calc;
+
+  /* if exponent is present */
+  if( *z=='e' || *z=='E' ){
+    z+=incr;
+    eValid = 0;
+    eType++;
+
+    /* This branch is needed to avoid a (harmless) buffer overread.  The
+    ** special comment alerts the mutation tester that the correct answer
+    ** is obtained even if the branch is omitted */
+    if( z>=zEnd ) goto do_atof_calc;              /*PREVENTS-HARMLESS-OVERREAD*/
+
+    /* get sign of exponent */
+    if( *z=='-' ){
+      esign = -1;
+      z+=incr;
+    }else if( *z=='+' ){
+      z+=incr;
+    }
+    /* copy digits to exponent */
+    while( z<zEnd && sqlite3Isdigit(*z) ){
+      e = e<10000 ? (e*10 + (*z - '0')) : 10000;
+      z+=incr;
+      eValid = 1;
+    }
+  }
+
+  /* skip trailing spaces */
+  while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
+
+do_atof_calc:
+  /* Zero is a special case */
+  if( s==0 ){
+    *pResult = sign<0 ? -0.0 : +0.0;
+    goto atof_return;
+  }
+
+  /* adjust exponent by d, and update sign */
+  e = (e*esign) + d;
+
+  /* Try to adjust the exponent to make it smaller */
+  while( e>0 && s<((LARGEST_UINT64-0x7ff)/10) ){
+    s *= 10;
+    e--;
+  }
+  while( e<0 && (s%10)==0 ){
+    s /= 10;
+    e++;
+  }
+
+  rr[0] = (double)s;
+  assert( sizeof(s2)==sizeof(rr[0]) );
+#ifdef SQLITE_DEBUG
+  rr[1] = 18446744073709549568.0;
+  memcpy(&s2, &rr[1], sizeof(s2));
+  assert( s2==0x43efffffffffffffLL );
+#endif
+  /* Largest double that can be safely converted to u64
+  **         vvvvvvvvvvvvvvvvvvvvvv   */
+  if( rr[0]<=18446744073709549568.0 ){
+    s2 = (u64)rr[0];
+    rr[1] = s>=s2 ? (double)(s - s2) : -(double)(s2 - s);
+  }else{
+    rr[1] = 0.0;
+  }
+  assert( rr[1]<=1.0e-10*rr[0] );  /* Equal only when rr[0]==0.0 */
+
+  if( e>0 ){
+    while( e>=100  ){
+      e -= 100;
+      dekkerMul2(rr, 1.0e+100, -1.5902891109759918046e+83);
+    }
+    while( e>=10   ){
+      e -= 10;
+      dekkerMul2(rr, 1.0e+10, 0.0);
+    }
+    while( e>=1    ){
+      e -= 1;
+      dekkerMul2(rr, 1.0e+01, 0.0);
+    }
+  }else{
+    while( e<=-100 ){
+      e += 100;
+      dekkerMul2(rr, 1.0e-100, -1.99918998026028836196e-117);
+    }
+    while( e<=-10  ){
+      e += 10;
+      dekkerMul2(rr, 1.0e-10, -3.6432197315497741579e-27);
+    }
+    while( e<=-1   ){
+      e += 1;
+      dekkerMul2(rr, 1.0e-01, -5.5511151231257827021e-18);
+    }
+  }
+  *pResult = rr[0]+rr[1];
+  if( sqlite3IsNaN(*pResult) ) *pResult = 1e300*1e300;
+  if( sign<0 ) *pResult = -*pResult;
+  assert( !sqlite3IsNaN(*pResult) );
+
+atof_return:
+  /* return true if number and no extra non-whitespace characters after */
+  if( z==zEnd && nDigit>0 && eValid && eType>0 ){
+    return eType;
+  }else if( eType>=2 && (eType==3 || eValid) && nDigit>0 ){
+    return -1;
+  }else{
+    return 0;
+  }
+#else
+  return !sqlite3Atoi64(z, pResult, length, enc);
+#endif /* SQLITE_OMIT_FLOATING_POINT */
+}
+#if defined(_MSC_VER)
+#pragma warning(default : 4756)
+#endif
+
+/*
+** Render an signed 64-bit integer as text.  Store the result in zOut[] and
+** return the length of the string that was stored, in bytes.  The value
+** returned does not include the zero terminator at the end of the output
+** string.
+**
+** The caller must ensure that zOut[] is at least 21 bytes in size.
+*/
+SQLITE_PRIVATE int sqlite3Int64ToText(i64 v, char *zOut){
+  int i;
+  u64 x;
+  char zTemp[22];
+  if( v<0 ){
+    x = (v==SMALLEST_INT64) ? ((u64)1)<<63 : (u64)-v;
+  }else{
+    x = v;
+  }
+  i = sizeof(zTemp)-2;
+  zTemp[sizeof(zTemp)-1] = 0;
+  while( 1 /*exit-by-break*/ ){
+    zTemp[i] = (x%10) + '0';
+    x = x/10;
+    if( x==0 ) break;
+    i--;
+  };
+  if( v<0 ) zTemp[--i] = '-';
+  memcpy(zOut, &zTemp[i], sizeof(zTemp)-i);
+  return sizeof(zTemp)-1-i;
+}
+
+/*
+** Compare the 19-character string zNum against the text representation
+** value 2^63:  9223372036854775808.  Return negative, zero, or positive
+** if zNum is less than, equal to, or greater than the string.
+** Note that zNum must contain exactly 19 characters.
+**
+** Unlike memcmp() this routine is guaranteed to return the difference
+** in the values of the last digit if the only difference is in the
+** last digit.  So, for example,
+**
+**      compare2pow63("9223372036854775800", 1)
+**
+** will return -8.
+*/
+static int compare2pow63(const char *zNum, int incr){
+  int c = 0;
+  int i;
+                    /* 012345678901234567 */
+  const char *pow63 = "922337203685477580";
+  for(i=0; c==0 && i<18; i++){
+    c = (zNum[i*incr]-pow63[i])*10;
+  }
+  if( c==0 ){
+    c = zNum[18*incr] - '8';
+    testcase( c==(-1) );
+    testcase( c==0 );
+    testcase( c==(+1) );
+  }
+  return c;
+}
+
+/*
+** Convert zNum to a 64-bit signed integer.  zNum must be decimal. This
+** routine does *not* accept hexadecimal notation.
+**
+** Returns:
+**
+**    -1    Not even a prefix of the input text looks like an integer
+**     0    Successful transformation.  Fits in a 64-bit signed integer.
+**     1    Excess non-space text after the integer value
+**     2    Integer too large for a 64-bit signed integer or is malformed
+**     3    Special case of 9223372036854775808
+**
+** length is the number of bytes in the string (bytes, not characters).
+** The string is not necessarily zero-terminated.  The encoding is
+** given by enc.
+*/
+SQLITE_PRIVATE int sqlite3Atoi64(const char *zNum, i64 *pNum, int length, u8 enc){
+  int incr;
+  u64 u = 0;
+  int neg = 0; /* assume positive */
+  int i;
+  int c = 0;
+  int nonNum = 0;  /* True if input contains UTF16 with high byte non-zero */
+  int rc;          /* Baseline return code */
+  const char *zStart;
+  const char *zEnd = zNum + length;
+  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
+  if( enc==SQLITE_UTF8 ){
+    incr = 1;
+  }else{
+    incr = 2;
+    length &= ~1;
+    assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
+    for(i=3-enc; i<length && zNum[i]==0; i+=2){}
+    nonNum = i<length;
+    zEnd = &zNum[i^1];
+    zNum += (enc&1);
+  }
+  while( zNum<zEnd && sqlite3Isspace(*zNum) ) zNum+=incr;
+  if( zNum<zEnd ){
+    if( *zNum=='-' ){
+      neg = 1;
+      zNum+=incr;
+    }else if( *zNum=='+' ){
+      zNum+=incr;
+    }
+  }
+  zStart = zNum;
+  while( zNum<zEnd && zNum[0]=='0' ){ zNum+=incr; } /* Skip leading zeros. */
+  for(i=0; &zNum[i]<zEnd && (c=zNum[i])>='0' && c<='9'; i+=incr){
+    u = u*10 + c - '0';
+  }
+  testcase( i==18*incr );
+  testcase( i==19*incr );
+  testcase( i==20*incr );
+  if( u>LARGEST_INT64 ){
+    /* This test and assignment is needed only to suppress UB warnings
+    ** from clang and -fsanitize=undefined.  This test and assignment make
+    ** the code a little larger and slower, and no harm comes from omitting
+    ** them, but we must appease the undefined-behavior pharisees. */
+    *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
+  }else if( neg ){
+    *pNum = -(i64)u;
+  }else{
+    *pNum = (i64)u;
+  }
+  rc = 0;
+  if( i==0 && zStart==zNum ){    /* No digits */
+    rc = -1;
+  }else if( nonNum ){            /* UTF16 with high-order bytes non-zero */
+    rc = 1;
+  }else if( &zNum[i]<zEnd ){     /* Extra bytes at the end */
+    int jj = i;
+    do{
+      if( !sqlite3Isspace(zNum[jj]) ){
+        rc = 1;          /* Extra non-space text after the integer */
+        break;
+      }
+      jj += incr;
+    }while( &zNum[jj]<zEnd );
+  }
+  if( i<19*incr ){
+    /* Less than 19 digits, so we know that it fits in 64 bits */
+    assert( u<=LARGEST_INT64 );
+    return rc;
+  }else{
+    /* zNum is a 19-digit numbers.  Compare it against 9223372036854775808. */
+    c = i>19*incr ? 1 : compare2pow63(zNum, incr);
+    if( c<0 ){
+      /* zNum is less than 9223372036854775808 so it fits */
+      assert( u<=LARGEST_INT64 );
+      return rc;
+    }else{
+      *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
+      if( c>0 ){
+        /* zNum is greater than 9223372036854775808 so it overflows */
+        return 2;
+      }else{
+        /* zNum is exactly 9223372036854775808.  Fits if negative.  The
+        ** special case 2 overflow if positive */
+        assert( u-1==LARGEST_INT64 );
+        return neg ? rc : 3;
+      }
+    }
+  }
+}
+
+/*
+** Transform a UTF-8 integer literal, in either decimal or hexadecimal,
+** into a 64-bit signed integer.  This routine accepts hexadecimal literals,
+** whereas sqlite3Atoi64() does not.
+**
+** Returns:
+**
+**     0    Successful transformation.  Fits in a 64-bit signed integer.
+**     1    Excess text after the integer value
+**     2    Integer too large for a 64-bit signed integer or is malformed
+**     3    Special case of 9223372036854775808
+*/
+SQLITE_PRIVATE int sqlite3DecOrHexToI64(const char *z, i64 *pOut){
+#ifndef SQLITE_OMIT_HEX_INTEGER
+  if( z[0]=='0'
+   && (z[1]=='x' || z[1]=='X')
+  ){
+    u64 u = 0;
+    int i, k;
+    for(i=2; z[i]=='0'; i++){}
+    for(k=i; sqlite3Isxdigit(z[k]); k++){
+      u = u*16 + sqlite3HexToInt(z[k]);
+    }
+    memcpy(pOut, &u, 8);
+    if( k-i>16 ) return 2;
+    if( z[k]!=0 ) return 1;
+    return 0;
+  }else
+#endif /* SQLITE_OMIT_HEX_INTEGER */
+  {
+    int n = (int)(0x3fffffff&strspn(z,"+- \n\t0123456789"));
+    if( z[n] ) n++;
+    return sqlite3Atoi64(z, pOut, n, SQLITE_UTF8);
+  }
+}
+
+/*
+** If zNum represents an integer that will fit in 32-bits, then set
+** *pValue to that integer and return true.  Otherwise return false.
+**
+** This routine accepts both decimal and hexadecimal notation for integers.
+**
+** Any non-numeric characters that following zNum are ignored.
+** This is different from sqlite3Atoi64() which requires the
+** input number to be zero-terminated.
+*/
+SQLITE_PRIVATE int sqlite3GetInt32(const char *zNum, int *pValue){
+  sqlite_int64 v = 0;
+  int i, c;
+  int neg = 0;
+  if( zNum[0]=='-' ){
+    neg = 1;
+    zNum++;
+  }else if( zNum[0]=='+' ){
+    zNum++;
+  }
+#ifndef SQLITE_OMIT_HEX_INTEGER
+  else if( zNum[0]=='0'
+        && (zNum[1]=='x' || zNum[1]=='X')
+        && sqlite3Isxdigit(zNum[2])
+  ){
+    u32 u = 0;
+    zNum += 2;
+    while( zNum[0]=='0' ) zNum++;
+    for(i=0; i<8 && sqlite3Isxdigit(zNum[i]); i++){
+      u = u*16 + sqlite3HexToInt(zNum[i]);
+    }
+    if( (u&0x80000000)==0 && sqlite3Isxdigit(zNum[i])==0 ){
+      memcpy(pValue, &u, 4);
+      return 1;
+    }else{
+      return 0;
+    }
+  }
+#endif
+  if( !sqlite3Isdigit(zNum[0]) ) return 0;
+  while( zNum[0]=='0' ) zNum++;
+  for(i=0; i<11 && (c = zNum[i] - '0')>=0 && c<=9; i++){
+    v = v*10 + c;
+  }
+
+  /* The longest decimal representation of a 32 bit integer is 10 digits:
+  **
+  **             1234567890
+  **     2^31 -> 2147483648
+  */
+  testcase( i==10 );
+  if( i>10 ){
+    return 0;
+  }
+  testcase( v-neg==2147483647 );
+  if( v-neg>2147483647 ){
+    return 0;
+  }
+  if( neg ){
+    v = -v;
+  }
+  *pValue = (int)v;
+  return 1;
+}
+
+/*
+** Return a 32-bit integer value extracted from a string.  If the
+** string is not an integer, just return 0.
+*/
+SQLITE_PRIVATE int sqlite3Atoi(const char *z){
+  int x = 0;
+  sqlite3GetInt32(z, &x);
+  return x;
+}
+
+/*
+** Decode a floating-point value into an approximate decimal
+** representation.
+**
+** If iRound<=0 then round to -iRound significant digits to the
+** the left of the decimal point, or to a maximum of mxRound total
+** significant digits.
+**
+** If iRound>0 round to min(iRound,mxRound) significant digits total.
+**
+** mxRound must be positive.
+**
+** The significant digits of the decimal representation are
+** stored in p->z[] which is a often (but not always) a pointer
+** into the middle of p->zBuf[].  There are p->n significant digits.
+** The p->z[] array is *not* zero-terminated.
+*/
+SQLITE_PRIVATE void sqlite3FpDecode(FpDecode *p, double r, int iRound, int mxRound){
+  int i;
+  u64 v;
+  int e, exp = 0;
+  double rr[2];
+
+  p->isSpecial = 0;
+  p->z = p->zBuf;
+  assert( mxRound>0 );
+
+  /* Convert negative numbers to positive.  Deal with Infinity, 0.0, and
+  ** NaN. */
+  if( r<0.0 ){
+    p->sign = '-';
+    r = -r;
+  }else if( r==0.0 ){
+    p->sign = '+';
+    p->n = 1;
+    p->iDP = 1;
+    p->z = "0";
+    return;
+  }else{
+    p->sign = '+';
+  }
+  memcpy(&v,&r,8);
+  e = v>>52;
+  if( (e&0x7ff)==0x7ff ){
+    p->isSpecial = 1 + (v!=0x7ff0000000000000LL);
+    p->n = 0;
+    p->iDP = 0;
+    return;
+  }
+
+  /* Multiply r by powers of ten until it lands somewhere in between
+  ** 1.0e+19 and 1.0e+17.
+  **
+  ** Use Dekker-style double-double computation to increase the
+  ** precision.
+  **
+  ** The error terms on constants like 1.0e+100 computed using the
+  ** decimal extension, for example as follows:
+  **
+  **   SELECT decimal_exp(decimal_sub('1.0e+100',decimal(1.0e+100)));
+  */
+  rr[0] = r;
+  rr[1] = 0.0;
+  if( rr[0]>9.223372036854774784e+18 ){
+    while( rr[0]>9.223372036854774784e+118 ){
+      exp += 100;
+      dekkerMul2(rr, 1.0e-100, -1.99918998026028836196e-117);
+    }
+    while( rr[0]>9.223372036854774784e+28 ){
+      exp += 10;
+      dekkerMul2(rr, 1.0e-10, -3.6432197315497741579e-27);
+    }
+    while( rr[0]>9.223372036854774784e+18 ){
+      exp += 1;
+      dekkerMul2(rr, 1.0e-01, -5.5511151231257827021e-18);
+    }
+  }else{
+    while( rr[0]<9.223372036854774784e-83  ){
+      exp -= 100;
+      dekkerMul2(rr, 1.0e+100, -1.5902891109759918046e+83);
+    }
+    while( rr[0]<9.223372036854774784e+07  ){
+      exp -= 10;
+      dekkerMul2(rr, 1.0e+10, 0.0);
+    }
+    while( rr[0]<9.22337203685477478e+17  ){
+      exp -= 1;
+      dekkerMul2(rr, 1.0e+01, 0.0);
+    }
+  }
+  v = rr[1]<0.0 ? (u64)rr[0]-(u64)(-rr[1]) : (u64)rr[0]+(u64)rr[1];
+
+  /* Extract significant digits. */
+  i = sizeof(p->zBuf)-1;
+  assert( v>0 );
+  while( v ){  p->zBuf[i--] = (v%10) + '0'; v /= 10; }
+  assert( i>=0 && i<sizeof(p->zBuf)-1 );
+  p->n = sizeof(p->zBuf) - 1 - i;
+  assert( p->n>0 );
+  assert( p->n<sizeof(p->zBuf) );
+  p->iDP = p->n + exp;
+  if( iRound<=0 ){
+    iRound = p->iDP - iRound;
+    if( iRound==0 && p->zBuf[i+1]>='5' ){
+      iRound = 1;
+      p->zBuf[i--] = '0';
+      p->n++;
+      p->iDP++;
+    }
+  }
+  if( iRound>0 && (iRound<p->n || p->n>mxRound) ){
+    char *z = &p->zBuf[i+1];
+    if( iRound>mxRound ) iRound = mxRound;
+    p->n = iRound;
+    if( z[iRound]>='5' ){
+      int j = iRound-1;
+      while( 1 /*exit-by-break*/ ){
+        z[j]++;
+        if( z[j]<='9' ) break;
+        z[j] = '0';
+        if( j==0 ){
+          p->z[i--] = '1';
+          p->n++;
+          p->iDP++;
+          break;
+        }else{
+          j--;
+        }
+      }
+    }
+  }
+  p->z = &p->zBuf[i+1];
+  assert( i+p->n < sizeof(p->zBuf) );
+  while( ALWAYS(p->n>0) && p->z[p->n-1]=='0' ){ p->n--; }
+}
+
+/*
+** Try to convert z into an unsigned 32-bit integer.  Return true on
+** success and false if there is an error.
+**
+** Only decimal notation is accepted.
+*/
+SQLITE_PRIVATE int sqlite3GetUInt32(const char *z, u32 *pI){
+  u64 v = 0;
+  int i;
+  for(i=0; sqlite3Isdigit(z[i]); i++){
+    v = v*10 + z[i] - '0';
+    if( v>4294967296LL ){ *pI = 0; return 0; }
+  }
+  if( i==0 || z[i]!=0 ){ *pI = 0; return 0; }
+  *pI = (u32)v;
+  return 1;
+}
+
+/*
+** The variable-length integer encoding is as follows:
+**
+** KEY:
+**         A = 0xxxxxxx    7 bits of data and one flag bit
+**         B = 1xxxxxxx    7 bits of data and one flag bit
+**         C = xxxxxxxx    8 bits of data
+**
+**  7 bits - A
+** 14 bits - BA
+** 21 bits - BBA
+** 28 bits - BBBA
+** 35 bits - BBBBA
+** 42 bits - BBBBBA
+** 49 bits - BBBBBBA
+** 56 bits - BBBBBBBA
+** 64 bits - BBBBBBBBC
+*/
+
+/*
+** Write a 64-bit variable-length integer to memory starting at p[0].
+** The length of data write will be between 1 and 9 bytes.  The number
+** of bytes written is returned.
+**
+** A variable-length integer consists of the lower 7 bits of each byte
+** for all bytes that have the 8th bit set and one byte with the 8th
+** bit clear.  Except, if we get to the 9th byte, it stores the full
+** 8 bits and is the last byte.
+*/
+static int SQLITE_NOINLINE putVarint64(unsigned char *p, u64 v){
+  int i, j, n;
+  u8 buf[10];
+  if( v & (((u64)0xff000000)<<32) ){
+    p[8] = (u8)v;
+    v >>= 8;
+    for(i=7; i>=0; i--){
+      p[i] = (u8)((v & 0x7f) | 0x80);
+      v >>= 7;
+    }
+    return 9;
+  }
+  n = 0;
+  do{
+    buf[n++] = (u8)((v & 0x7f) | 0x80);
+    v >>= 7;
+  }while( v!=0 );
+  buf[0] &= 0x7f;
+  assert( n<=9 );
+  for(i=0, j=n-1; j>=0; j--, i++){
+    p[i] = buf[j];
+  }
+  return n;
+}
+SQLITE_PRIVATE int sqlite3PutVarint(unsigned char *p, u64 v){
+  if( v<=0x7f ){
+    p[0] = v&0x7f;
+    return 1;
+  }
+  if( v<=0x3fff ){
+    p[0] = ((v>>7)&0x7f)|0x80;
+    p[1] = v&0x7f;
+    return 2;
+  }
+  return putVarint64(p,v);
+}
+
+/*
+** Bitmasks used by sqlite3GetVarint().  These precomputed constants
+** are defined here rather than simply putting the constant expressions
+** inline in order to work around bugs in the RVT compiler.
+**
+** SLOT_2_0     A mask for  (0x7f<<14) | 0x7f
+**
+** SLOT_4_2_0   A mask for  (0x7f<<28) | SLOT_2_0
+*/
+#define SLOT_2_0     0x001fc07f
+#define SLOT_4_2_0   0xf01fc07f
+
+
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read.  The value is stored in *v.
+*/
+SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
+  u32 a,b,s;
+
+  if( ((signed char*)p)[0]>=0 ){
+    *v = *p;
+    return 1;
+  }
+  if( ((signed char*)p)[1]>=0 ){
+    *v = ((u32)(p[0]&0x7f)<<7) | p[1];
+    return 2;
+  }
+
+  /* Verify that constants are precomputed correctly */
+  assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
+  assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
+
+  a = ((u32)p[0])<<14;
+  b = p[1];
+  p += 2;
+  a |= *p;
+  /* a: p0<<14 | p2 (unmasked) */
+  if (!(a&0x80))
+  {
+    a &= SLOT_2_0;
+    b &= 0x7f;
+    b = b<<7;
+    a |= b;
+    *v = a;
+    return 3;
+  }
+
+  /* CSE1 from below */
+  a &= SLOT_2_0;
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<14 | p3 (unmasked) */
+  if (!(b&0x80))
+  {
+    b &= SLOT_2_0;
+    /* moved CSE1 up */
+    /* a &= (0x7f<<14)|(0x7f); */
+    a = a<<7;
+    a |= b;
+    *v = a;
+    return 4;
+  }
+
+  /* a: p0<<14 | p2 (masked) */
+  /* b: p1<<14 | p3 (unmasked) */
+  /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+  /* moved CSE1 up */
+  /* a &= (0x7f<<14)|(0x7f); */
+  b &= SLOT_2_0;
+  s = a;
+  /* s: p0<<14 | p2 (masked) */
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<28 | p2<<14 | p4 (unmasked) */
+  if (!(a&0x80))
+  {
+    /* we can skip these cause they were (effectively) done above
+    ** while calculating s */
+    /* a &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
+    /* b &= (0x7f<<14)|(0x7f); */
+    b = b<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 5;
+  }
+
+  /* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+  s = s<<7;
+  s |= b;
+  /* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<28 | p3<<14 | p5 (unmasked) */
+  if (!(b&0x80))
+  {
+    /* we can skip this cause it was (effectively) done above in calc'ing s */
+    /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
+    a &= SLOT_2_0;
+    a = a<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 6;
+  }
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p2<<28 | p4<<14 | p6 (unmasked) */
+  if (!(a&0x80))
+  {
+    a &= SLOT_4_2_0;
+    b &= SLOT_2_0;
+    b = b<<7;
+    a |= b;
+    s = s>>11;
+    *v = ((u64)s)<<32 | a;
+    return 7;
+  }
+
+  /* CSE2 from below */
+  a &= SLOT_2_0;
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p3<<28 | p5<<14 | p7 (unmasked) */
+  if (!(b&0x80))
+  {
+    b &= SLOT_4_2_0;
+    /* moved CSE2 up */
+    /* a &= (0x7f<<14)|(0x7f); */
+    a = a<<7;
+    a |= b;
+    s = s>>4;
+    *v = ((u64)s)<<32 | a;
+    return 8;
+  }
+
+  p++;
+  a = a<<15;
+  a |= *p;
+  /* a: p4<<29 | p6<<15 | p8 (unmasked) */
+
+  /* moved CSE2 up */
+  /* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
+  b &= SLOT_2_0;
+  b = b<<8;
+  a |= b;
+
+  s = s<<4;
+  b = p[-4];
+  b &= 0x7f;
+  b = b>>3;
+  s |= b;
+
+  *v = ((u64)s)<<32 | a;
+
+  return 9;
+}
+
+/*
+** Read a 32-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read.  The value is stored in *v.
+**
+** If the varint stored in p[0] is larger than can fit in a 32-bit unsigned
+** integer, then set *v to 0xffffffff.
+**
+** A MACRO version, getVarint32, is provided which inlines the
+** single-byte case.  All code should use the MACRO version as
+** this function assumes the single-byte case has already been handled.
+*/
+SQLITE_PRIVATE u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
+  u64 v64;
+  u8 n;
+
+  /* Assume that the single-byte case has already been handled by
+  ** the getVarint32() macro */
+  assert( (p[0] & 0x80)!=0 );
+
+  if( (p[1] & 0x80)==0 ){
+    /* This is the two-byte case */
+    *v = ((p[0]&0x7f)<<7) | p[1];
+    return 2;
+  }
+  if( (p[2] & 0x80)==0 ){
+    /* This is the three-byte case */
+    *v = ((p[0]&0x7f)<<14) | ((p[1]&0x7f)<<7) | p[2];
+    return 3;
+  }
+  /* four or more bytes */
+  n = sqlite3GetVarint(p, &v64);
+  assert( n>3 && n<=9 );
+  if( (v64 & SQLITE_MAX_U32)!=v64 ){
+    *v = 0xffffffff;
+  }else{
+    *v = (u32)v64;
+  }
+  return n;
+}
+
+/*
+** Return the number of bytes that will be needed to store the given
+** 64-bit integer.
+*/
+SQLITE_PRIVATE int sqlite3VarintLen(u64 v){
+  int i;
+  for(i=1; (v >>= 7)!=0; i++){ assert( i<10 ); }
+  return i;
+}
+
+
+/*
+** Read or write a four-byte big-endian integer value.
+*/
+SQLITE_PRIVATE u32 sqlite3Get4byte(const u8 *p){
+#if SQLITE_BYTEORDER==4321
+  u32 x;
+  memcpy(&x,p,4);
+  return x;
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  u32 x;
+  memcpy(&x,p,4);
+  return __builtin_bswap32(x);
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  u32 x;
+  memcpy(&x,p,4);
+  return _byteswap_ulong(x);
+#else
+  testcase( p[0]&0x80 );
+  return ((unsigned)p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
+#endif
+}
+SQLITE_PRIVATE void sqlite3Put4byte(unsigned char *p, u32 v){
+#if SQLITE_BYTEORDER==4321
+  memcpy(p,&v,4);
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  u32 x = __builtin_bswap32(v);
+  memcpy(p,&x,4);
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  u32 x = _byteswap_ulong(v);
+  memcpy(p,&x,4);
+#else
+  p[0] = (u8)(v>>24);
+  p[1] = (u8)(v>>16);
+  p[2] = (u8)(v>>8);
+  p[3] = (u8)v;
+#endif
+}
+
+
+
+/*
+** Translate a single byte of Hex into an integer.
+** This routine only works if h really is a valid hexadecimal
+** character:  0..9a..fA..F
+*/
+SQLITE_PRIVATE u8 sqlite3HexToInt(int h){
+  assert( (h>='0' && h<='9') ||  (h>='a' && h<='f') ||  (h>='A' && h<='F') );
+#ifdef SQLITE_ASCII
+  h += 9*(1&(h>>6));
+#endif
+#ifdef SQLITE_EBCDIC
+  h += 9*(1&~(h>>4));
+#endif
+  return (u8)(h & 0xf);
+}
+
+#if !defined(SQLITE_OMIT_BLOB_LITERAL)
+/*
+** Convert a BLOB literal of the form "x'hhhhhh'" into its binary
+** value.  Return a pointer to its binary value.  Space to hold the
+** binary value has been obtained from malloc and must be freed by
+** the calling routine.
+*/
+SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3 *db, const char *z, int n){
+  char *zBlob;
+  int i;
+
+  zBlob = (char *)sqlite3DbMallocRawNN(db, n/2 + 1);
+  n--;
+  if( zBlob ){
+    for(i=0; i<n; i+=2){
+      zBlob[i/2] = (sqlite3HexToInt(z[i])<<4) | sqlite3HexToInt(z[i+1]);
+    }
+    zBlob[i/2] = 0;
+  }
+  return zBlob;
+}
+#endif /* !SQLITE_OMIT_BLOB_LITERAL */
+
+/*
+** Log an error that is an API call on a connection pointer that should
+** not have been used.  The "type" of connection pointer is given as the
+** argument.  The zType is a word like "NULL" or "closed" or "invalid".
+*/
+static void logBadConnection(const char *zType){
+  sqlite3_log(SQLITE_MISUSE,
+     "API call with %s database connection pointer",
+     zType
+  );
+}
+
+/*
+** Check to make sure we have a valid db pointer.  This test is not
+** foolproof but it does provide some measure of protection against
+** misuse of the interface such as passing in db pointers that are
+** NULL or which have been previously closed.  If this routine returns
+** 1 it means that the db pointer is valid and 0 if it should not be
+** dereferenced for any reason.  The calling function should invoke
+** SQLITE_MISUSE immediately.
+**
+** sqlite3SafetyCheckOk() requires that the db pointer be valid for
+** use.  sqlite3SafetyCheckSickOrOk() allows a db pointer that failed to
+** open properly and is not fit for general use but which can be
+** used as an argument to sqlite3_errmsg() or sqlite3_close().
+*/
+SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3 *db){
+  u8 eOpenState;
+  if( db==0 ){
+    logBadConnection("NULL");
+    return 0;
+  }
+  eOpenState = db->eOpenState;
+  if( eOpenState!=SQLITE_STATE_OPEN ){
+    if( sqlite3SafetyCheckSickOrOk(db) ){
+      testcase( sqlite3GlobalConfig.xLog!=0 );
+      logBadConnection("unopened");
+    }
+    return 0;
+  }else{
+    return 1;
+  }
+}
+SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
+  u8 eOpenState;
+  eOpenState = db->eOpenState;
+  if( eOpenState!=SQLITE_STATE_SICK &&
+      eOpenState!=SQLITE_STATE_OPEN &&
+      eOpenState!=SQLITE_STATE_BUSY ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    logBadConnection("invalid");
+    return 0;
+  }else{
+    return 1;
+  }
+}
+
+/*
+** Attempt to add, subtract, or multiply the 64-bit signed value iB against
+** the other 64-bit signed integer at *pA and store the result in *pA.
+** Return 0 on success.  Or if the operation would have resulted in an
+** overflow, leave *pA unchanged and return 1.
+*/
+SQLITE_PRIVATE int sqlite3AddInt64(i64 *pA, i64 iB){
+#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
+  return __builtin_add_overflow(*pA, iB, pA);
+#else
+  i64 iA = *pA;
+  testcase( iA==0 ); testcase( iA==1 );
+  testcase( iB==-1 ); testcase( iB==0 );
+  if( iB>=0 ){
+    testcase( iA>0 && LARGEST_INT64 - iA == iB );
+    testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
+    if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
+  }else{
+    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
+    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
+    if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
+  }
+  *pA += iB;
+  return 0;
+#endif
+}
+SQLITE_PRIVATE int sqlite3SubInt64(i64 *pA, i64 iB){
+#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
+  return __builtin_sub_overflow(*pA, iB, pA);
+#else
+  testcase( iB==SMALLEST_INT64+1 );
+  if( iB==SMALLEST_INT64 ){
+    testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
+    if( (*pA)>=0 ) return 1;
+    *pA -= iB;
+    return 0;
+  }else{
+    return sqlite3AddInt64(pA, -iB);
+  }
+#endif
+}
+SQLITE_PRIVATE int sqlite3MulInt64(i64 *pA, i64 iB){
+#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
+  return __builtin_mul_overflow(*pA, iB, pA);
+#else
+  i64 iA = *pA;
+  if( iB>0 ){
+    if( iA>LARGEST_INT64/iB ) return 1;
+    if( iA<SMALLEST_INT64/iB ) return 1;
+  }else if( iB<0 ){
+    if( iA>0 ){
+      if( iB<SMALLEST_INT64/iA ) return 1;
+    }else if( iA<0 ){
+      if( iB==SMALLEST_INT64 ) return 1;
+      if( iA==SMALLEST_INT64 ) return 1;
+      if( -iA>LARGEST_INT64/-iB ) return 1;
+    }
+  }
+  *pA = iA*iB;
+  return 0;
+#endif
+}
+
+/*
+** Compute the absolute value of a 32-bit signed integer, of possible.  Or
+** if the integer has a value of -2147483648, return +2147483647
+*/
+SQLITE_PRIVATE int sqlite3AbsInt32(int x){
+  if( x>=0 ) return x;
+  if( x==(int)0x80000000 ) return 0x7fffffff;
+  return -x;
+}
+
+#ifdef SQLITE_ENABLE_8_3_NAMES
+/*
+** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
+** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
+** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
+** three characters, then shorten the suffix on z[] to be the last three
+** characters of the original suffix.
+**
+** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
+** do the suffix shortening regardless of URI parameter.
+**
+** Examples:
+**
+**     test.db-journal    =>   test.nal
+**     test.db-wal        =>   test.wal
+**     test.db-shm        =>   test.shm
+**     test.db-mj7f3319fa =>   test.9fa
+*/
+SQLITE_PRIVATE void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
+#if SQLITE_ENABLE_8_3_NAMES<2
+  if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
+#endif
+  {
+    int i, sz;
+    sz = sqlite3Strlen30(z);
+    for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
+    if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
+  }
+}
+#endif
+
+/*
+** Find (an approximate) sum of two LogEst values.  This computation is
+** not a simple "+" operator because LogEst is stored as a logarithmic
+** value.
+**
+*/
+SQLITE_PRIVATE LogEst sqlite3LogEstAdd(LogEst a, LogEst b){
+  static const unsigned char x[] = {
+     10, 10,                         /* 0,1 */
+      9, 9,                          /* 2,3 */
+      8, 8,                          /* 4,5 */
+      7, 7, 7,                       /* 6,7,8 */
+      6, 6, 6,                       /* 9,10,11 */
+      5, 5, 5,                       /* 12-14 */
+      4, 4, 4, 4,                    /* 15-18 */
+      3, 3, 3, 3, 3, 3,              /* 19-24 */
+      2, 2, 2, 2, 2, 2, 2,           /* 25-31 */
+  };
+  if( a>=b ){
+    if( a>b+49 ) return a;
+    if( a>b+31 ) return a+1;
+    return a+x[a-b];
+  }else{
+    if( b>a+49 ) return b;
+    if( b>a+31 ) return b+1;
+    return b+x[b-a];
+  }
+}
+
+/*
+** Convert an integer into a LogEst.  In other words, compute an
+** approximation for 10*log2(x).
+*/
+SQLITE_PRIVATE LogEst sqlite3LogEst(u64 x){
+  static LogEst a[] = { 0, 2, 3, 5, 6, 7, 8, 9 };
+  LogEst y = 40;
+  if( x<8 ){
+    if( x<2 ) return 0;
+    while( x<8 ){  y -= 10; x <<= 1; }
+  }else{
+#if GCC_VERSION>=5004000
+    int i = 60 - __builtin_clzll(x);
+    y += i*10;
+    x >>= i;
+#else
+    while( x>255 ){ y += 40; x >>= 4; }  /*OPTIMIZATION-IF-TRUE*/
+    while( x>15 ){  y += 10; x >>= 1; }
+#endif
+  }
+  return a[x&7] + y - 10;
+}
+
+/*
+** Convert a double into a LogEst
+** In other words, compute an approximation for 10*log2(x).
+*/
+SQLITE_PRIVATE LogEst sqlite3LogEstFromDouble(double x){
+  u64 a;
+  LogEst e;
+  assert( sizeof(x)==8 && sizeof(a)==8 );
+  if( x<=1 ) return 0;
+  if( x<=2000000000 ) return sqlite3LogEst((u64)x);
+  memcpy(&a, &x, 8);
+  e = (a>>52) - 1022;
+  return e*10;
+}
+
+/*
+** Convert a LogEst into an integer.
+*/
+SQLITE_PRIVATE u64 sqlite3LogEstToInt(LogEst x){
+  u64 n;
+  n = x%10;
+  x /= 10;
+  if( n>=5 ) n -= 2;
+  else if( n>=1 ) n -= 1;
+  if( x>60 ) return (u64)LARGEST_INT64;
+  return x>=3 ? (n+8)<<(x-3) : (n+8)>>(3-x);
+}
+
+/*
+** Add a new name/number pair to a VList.  This might require that the
+** VList object be reallocated, so return the new VList.  If an OOM
+** error occurs, the original VList returned and the
+** db->mallocFailed flag is set.
+**
+** A VList is really just an array of integers.  To destroy a VList,
+** simply pass it to sqlite3DbFree().
+**
+** The first integer is the number of integers allocated for the whole
+** VList.  The second integer is the number of integers actually used.
+** Each name/number pair is encoded by subsequent groups of 3 or more
+** integers.
+**
+** Each name/number pair starts with two integers which are the numeric
+** value for the pair and the size of the name/number pair, respectively.
+** The text name overlays one or more following integers.  The text name
+** is always zero-terminated.
+**
+** Conceptually:
+**
+**    struct VList {
+**      int nAlloc;   // Number of allocated slots
+**      int nUsed;    // Number of used slots
+**      struct VListEntry {
+**        int iValue;    // Value for this entry
+**        int nSlot;     // Slots used by this entry
+**        // ... variable name goes here
+**      } a[0];
+**    }
+**
+** During code generation, pointers to the variable names within the
+** VList are taken.  When that happens, nAlloc is set to zero as an
+** indication that the VList may never again be enlarged, since the
+** accompanying realloc() would invalidate the pointers.
+*/
+SQLITE_PRIVATE VList *sqlite3VListAdd(
+  sqlite3 *db,           /* The database connection used for malloc() */
+  VList *pIn,            /* The input VList.  Might be NULL */
+  const char *zName,     /* Name of symbol to add */
+  int nName,             /* Bytes of text in zName */
+  int iVal               /* Value to associate with zName */
+){
+  int nInt;              /* number of sizeof(int) objects needed for zName */
+  char *z;               /* Pointer to where zName will be stored */
+  int i;                 /* Index in pIn[] where zName is stored */
+
+  nInt = nName/4 + 3;
+  assert( pIn==0 || pIn[0]>=3 );  /* Verify ok to add new elements */
+  if( pIn==0 || pIn[1]+nInt > pIn[0] ){
+    /* Enlarge the allocation */
+    sqlite3_int64 nAlloc = (pIn ? 2*(sqlite3_int64)pIn[0] : 10) + nInt;
+    VList *pOut = sqlite3DbRealloc(db, pIn, nAlloc*sizeof(int));
+    if( pOut==0 ) return pIn;
+    if( pIn==0 ) pOut[1] = 2;
+    pIn = pOut;
+    pIn[0] = nAlloc;
+  }
+  i = pIn[1];
+  pIn[i] = iVal;
+  pIn[i+1] = nInt;
+  z = (char*)&pIn[i+2];
+  pIn[1] = i+nInt;
+  assert( pIn[1]<=pIn[0] );
+  memcpy(z, zName, nName);
+  z[nName] = 0;
+  return pIn;
+}
+
+/*
+** Return a pointer to the name of a variable in the given VList that
+** has the value iVal.  Or return a NULL if there is no such variable in
+** the list
+*/
+SQLITE_PRIVATE const char *sqlite3VListNumToName(VList *pIn, int iVal){
+  int i, mx;
+  if( pIn==0 ) return 0;
+  mx = pIn[1];
+  i = 2;
+  do{
+    if( pIn[i]==iVal ) return (char*)&pIn[i+2];
+    i += pIn[i+1];
+  }while( i<mx );
+  return 0;
+}
+
+/*
+** Return the number of the variable named zName, if it is in VList.
+** or return 0 if there is no such variable.
+*/
+SQLITE_PRIVATE int sqlite3VListNameToNum(VList *pIn, const char *zName, int nName){
+  int i, mx;
+  if( pIn==0 ) return 0;
+  mx = pIn[1];
+  i = 2;
+  do{
+    const char *z = (const char*)&pIn[i+2];
+    if( strncmp(z,zName,nName)==0 && z[nName]==0 ) return pIn[i];
+    i += pIn[i+1];
+  }while( i<mx );
+  return 0;
+}
+
+/************** End of util.c ************************************************/
+/************** Begin file hash.c ********************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the implementation of generic hash-tables
+** used in SQLite.
+*/
+/* #include "sqliteInt.h" */
+/* #include <assert.h> */
+
+/* Turn bulk memory into a hash table object by initializing the
+** fields of the Hash structure.
+**
+** "pNew" is a pointer to the hash table that is to be initialized.
+*/
+SQLITE_PRIVATE void sqlite3HashInit(Hash *pNew){
+  assert( pNew!=0 );
+  pNew->first = 0;
+  pNew->count = 0;
+  pNew->htsize = 0;
+  pNew->ht = 0;
+}
+
+/* Remove all entries from a hash table.  Reclaim all memory.
+** Call this routine to delete a hash table or to reset a hash table
+** to the empty state.
+*/
+SQLITE_PRIVATE void sqlite3HashClear(Hash *pH){
+  HashElem *elem;         /* For looping over all elements of the table */
+
+  assert( pH!=0 );
+  elem = pH->first;
+  pH->first = 0;
+  sqlite3_free(pH->ht);
+  pH->ht = 0;
+  pH->htsize = 0;
+  while( elem ){
+    HashElem *next_elem = elem->next;
+    sqlite3_free(elem);
+    elem = next_elem;
+  }
+  pH->count = 0;
+}
+
+/*
+** The hashing function.
+*/
+static unsigned int strHash(const char *z){
+  unsigned int h = 0;
+  unsigned char c;
+  while( (c = (unsigned char)*z++)!=0 ){     /*OPTIMIZATION-IF-TRUE*/
+    /* Knuth multiplicative hashing.  (Sorting & Searching, p. 510).
+    ** 0x9e3779b1 is 2654435761 which is the closest prime number to
+    ** (2**32)*golden_ratio, where golden_ratio = (sqrt(5) - 1)/2. */
+    h += sqlite3UpperToLower[c];
+    h *= 0x9e3779b1;
+  }
+  return h;
+}
+
+
+/* Link pNew element into the hash table pH.  If pEntry!=0 then also
+** insert pNew into the pEntry hash bucket.
+*/
+static void insertElement(
+  Hash *pH,              /* The complete hash table */
+  struct _ht *pEntry,    /* The entry into which pNew is inserted */
+  HashElem *pNew         /* The element to be inserted */
+){
+  HashElem *pHead;       /* First element already in pEntry */
+  if( pEntry ){
+    pHead = pEntry->count ? pEntry->chain : 0;
+    pEntry->count++;
+    pEntry->chain = pNew;
+  }else{
+    pHead = 0;
+  }
+  if( pHead ){
+    pNew->next = pHead;
+    pNew->prev = pHead->prev;
+    if( pHead->prev ){ pHead->prev->next = pNew; }
+    else             { pH->first = pNew; }
+    pHead->prev = pNew;
+  }else{
+    pNew->next = pH->first;
+    if( pH->first ){ pH->first->prev = pNew; }
+    pNew->prev = 0;
+    pH->first = pNew;
+  }
+}
+
+
+/* Resize the hash table so that it contains "new_size" buckets.
+**
+** The hash table might fail to resize if sqlite3_malloc() fails or
+** if the new size is the same as the prior size.
+** Return TRUE if the resize occurs and false if not.
+*/
+static int rehash(Hash *pH, unsigned int new_size){
+  struct _ht *new_ht;            /* The new hash table */
+  HashElem *elem, *next_elem;    /* For looping over existing elements */
+
+#if SQLITE_MALLOC_SOFT_LIMIT>0
+  if( new_size*sizeof(struct _ht)>SQLITE_MALLOC_SOFT_LIMIT ){
+    new_size = SQLITE_MALLOC_SOFT_LIMIT/sizeof(struct _ht);
+  }
+  if( new_size==pH->htsize ) return 0;
+#endif
+
+  /* The inability to allocates space for a larger hash table is
+  ** a performance hit but it is not a fatal error.  So mark the
+  ** allocation as a benign. Use sqlite3Malloc()/memset(0) instead of
+  ** sqlite3MallocZero() to make the allocation, as sqlite3MallocZero()
+  ** only zeroes the requested number of bytes whereas this module will
+  ** use the actual amount of space allocated for the hash table (which
+  ** may be larger than the requested amount).
+  */
+  sqlite3BeginBenignMalloc();
+  new_ht = (struct _ht *)sqlite3Malloc( new_size*sizeof(struct _ht) );
+  sqlite3EndBenignMalloc();
+
+  if( new_ht==0 ) return 0;
+  sqlite3_free(pH->ht);
+  pH->ht = new_ht;
+  pH->htsize = new_size = sqlite3MallocSize(new_ht)/sizeof(struct _ht);
+  memset(new_ht, 0, new_size*sizeof(struct _ht));
+  for(elem=pH->first, pH->first=0; elem; elem = next_elem){
+    unsigned int h = strHash(elem->pKey) % new_size;
+    next_elem = elem->next;
+    insertElement(pH, &new_ht[h], elem);
+  }
+  return 1;
+}
+
+/* This function (for internal use only) locates an element in an
+** hash table that matches the given key.  If no element is found,
+** a pointer to a static null element with HashElem.data==0 is returned.
+** If pH is not NULL, then the hash for this key is written to *pH.
+*/
+static HashElem *findElementWithHash(
+  const Hash *pH,     /* The pH to be searched */
+  const char *pKey,   /* The key we are searching for */
+  unsigned int *pHash /* Write the hash value here */
+){
+  HashElem *elem;                /* Used to loop thru the element list */
+  unsigned int count;            /* Number of elements left to test */
+  unsigned int h;                /* The computed hash */
+  static HashElem nullElement = { 0, 0, 0, 0 };
+
+  if( pH->ht ){   /*OPTIMIZATION-IF-TRUE*/
+    struct _ht *pEntry;
+    h = strHash(pKey) % pH->htsize;
+    pEntry = &pH->ht[h];
+    elem = pEntry->chain;
+    count = pEntry->count;
+  }else{
+    h = 0;
+    elem = pH->first;
+    count = pH->count;
+  }
+  if( pHash ) *pHash = h;
+  while( count ){
+    assert( elem!=0 );
+    if( sqlite3StrICmp(elem->pKey,pKey)==0 ){
+      return elem;
+    }
+    elem = elem->next;
+    count--;
+  }
+  return &nullElement;
+}
+
+/* Remove a single entry from the hash table given a pointer to that
+** element and a hash on the element's key.
+*/
+static void removeElementGivenHash(
+  Hash *pH,         /* The pH containing "elem" */
+  HashElem* elem,   /* The element to be removed from the pH */
+  unsigned int h    /* Hash value for the element */
+){
+  struct _ht *pEntry;
+  if( elem->prev ){
+    elem->prev->next = elem->next;
+  }else{
+    pH->first = elem->next;
+  }
+  if( elem->next ){
+    elem->next->prev = elem->prev;
+  }
+  if( pH->ht ){
+    pEntry = &pH->ht[h];
+    if( pEntry->chain==elem ){
+      pEntry->chain = elem->next;
+    }
+    assert( pEntry->count>0 );
+    pEntry->count--;
+  }
+  sqlite3_free( elem );
+  pH->count--;
+  if( pH->count==0 ){
+    assert( pH->first==0 );
+    assert( pH->count==0 );
+    sqlite3HashClear(pH);
+  }
+}
+
+/* Attempt to locate an element of the hash table pH with a key
+** that matches pKey.  Return the data for this element if it is
+** found, or NULL if there is no match.
+*/
+SQLITE_PRIVATE void *sqlite3HashFind(const Hash *pH, const char *pKey){
+  assert( pH!=0 );
+  assert( pKey!=0 );
+  return findElementWithHash(pH, pKey, 0)->data;
+}
+
+/* Insert an element into the hash table pH.  The key is pKey
+** and the data is "data".
+**
+** If no element exists with a matching key, then a new
+** element is created and NULL is returned.
+**
+** If another element already exists with the same key, then the
+** new data replaces the old data and the old data is returned.
+** The key is not copied in this instance.  If a malloc fails, then
+** the new data is returned and the hash table is unchanged.
+**
+** If the "data" parameter to this function is NULL, then the
+** element corresponding to "key" is removed from the hash table.
+*/
+SQLITE_PRIVATE void *sqlite3HashInsert(Hash *pH, const char *pKey, void *data){
+  unsigned int h;       /* the hash of the key modulo hash table size */
+  HashElem *elem;       /* Used to loop thru the element list */
+  HashElem *new_elem;   /* New element added to the pH */
+
+  assert( pH!=0 );
+  assert( pKey!=0 );
+  elem = findElementWithHash(pH,pKey,&h);
+  if( elem->data ){
+    void *old_data = elem->data;
+    if( data==0 ){
+      removeElementGivenHash(pH,elem,h);
+    }else{
+      elem->data = data;
+      elem->pKey = pKey;
+    }
+    return old_data;
+  }
+  if( data==0 ) return 0;
+  new_elem = (HashElem*)sqlite3Malloc( sizeof(HashElem) );
+  if( new_elem==0 ) return data;
+  new_elem->pKey = pKey;
+  new_elem->data = data;
+  pH->count++;
+  if( pH->count>=10 && pH->count > 2*pH->htsize ){
+    if( rehash(pH, pH->count*2) ){
+      assert( pH->htsize>0 );
+      h = strHash(pKey) % pH->htsize;
+    }
+  }
+  insertElement(pH, pH->ht ? &pH->ht[h] : 0, new_elem);
+  return 0;
+}
+
+/************** End of hash.c ************************************************/
+/************** Begin file opcodes.c *****************************************/
+/* Automatically generated.  Do not edit */
+/* See the tool/mkopcodec.tcl script for details. */
+#if !defined(SQLITE_OMIT_EXPLAIN) \
+ || defined(VDBE_PROFILE) \
+ || defined(SQLITE_DEBUG)
+#if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS) || defined(SQLITE_DEBUG)
+# define OpHelp(X) "\0" X
+#else
+# define OpHelp(X)
+#endif
+SQLITE_PRIVATE const char *sqlite3OpcodeName(int i){
+ static const char *const azName[] = {
+    /*   0 */ "Savepoint"        OpHelp(""),
+    /*   1 */ "AutoCommit"       OpHelp(""),
+    /*   2 */ "Transaction"      OpHelp(""),
+    /*   3 */ "Checkpoint"       OpHelp(""),
+    /*   4 */ "JournalMode"      OpHelp(""),
+    /*   5 */ "Vacuum"           OpHelp(""),
+    /*   6 */ "VFilter"          OpHelp("iplan=r[P3] zplan='P4'"),
+    /*   7 */ "VUpdate"          OpHelp("data=r[P3@P2]"),
+    /*   8 */ "Init"             OpHelp("Start at P2"),
+    /*   9 */ "Goto"             OpHelp(""),
+    /*  10 */ "Gosub"            OpHelp(""),
+    /*  11 */ "InitCoroutine"    OpHelp(""),
+    /*  12 */ "Yield"            OpHelp(""),
+    /*  13 */ "MustBeInt"        OpHelp(""),
+    /*  14 */ "Jump"             OpHelp(""),
+    /*  15 */ "Once"             OpHelp(""),
+    /*  16 */ "If"               OpHelp(""),
+    /*  17 */ "IfNot"            OpHelp(""),
+    /*  18 */ "IsType"           OpHelp("if typeof(P1.P3) in P5 goto P2"),
+    /*  19 */ "Not"              OpHelp("r[P2]= !r[P1]"),
+    /*  20 */ "IfNullRow"        OpHelp("if P1.nullRow then r[P3]=NULL, goto P2"),
+    /*  21 */ "SeekLT"           OpHelp("key=r[P3@P4]"),
+    /*  22 */ "SeekLE"           OpHelp("key=r[P3@P4]"),
+    /*  23 */ "SeekGE"           OpHelp("key=r[P3@P4]"),
+    /*  24 */ "SeekGT"           OpHelp("key=r[P3@P4]"),
+    /*  25 */ "IfNotOpen"        OpHelp("if( !csr[P1] ) goto P2"),
+    /*  26 */ "IfNoHope"         OpHelp("key=r[P3@P4]"),
+    /*  27 */ "NoConflict"       OpHelp("key=r[P3@P4]"),
+    /*  28 */ "NotFound"         OpHelp("key=r[P3@P4]"),
+    /*  29 */ "Found"            OpHelp("key=r[P3@P4]"),
+    /*  30 */ "SeekRowid"        OpHelp("intkey=r[P3]"),
+    /*  31 */ "NotExists"        OpHelp("intkey=r[P3]"),
+    /*  32 */ "Last"             OpHelp(""),
+    /*  33 */ "IfSizeBetween"    OpHelp(""),
+    /*  34 */ "SorterSort"       OpHelp(""),
+    /*  35 */ "Sort"             OpHelp(""),
+    /*  36 */ "Rewind"           OpHelp(""),
+    /*  37 */ "SorterNext"       OpHelp(""),
+    /*  38 */ "Prev"             OpHelp(""),
+    /*  39 */ "Next"             OpHelp(""),
+    /*  40 */ "IdxLE"            OpHelp("key=r[P3@P4]"),
+    /*  41 */ "IdxGT"            OpHelp("key=r[P3@P4]"),
+    /*  42 */ "IdxLT"            OpHelp("key=r[P3@P4]"),
+    /*  43 */ "Or"               OpHelp("r[P3]=(r[P1] || r[P2])"),
+    /*  44 */ "And"              OpHelp("r[P3]=(r[P1] && r[P2])"),
+    /*  45 */ "IdxGE"            OpHelp("key=r[P3@P4]"),
+    /*  46 */ "RowSetRead"       OpHelp("r[P3]=rowset(P1)"),
+    /*  47 */ "RowSetTest"       OpHelp("if r[P3] in rowset(P1) goto P2"),
+    /*  48 */ "Program"          OpHelp(""),
+    /*  49 */ "FkIfZero"         OpHelp("if fkctr[P1]==0 goto P2"),
+    /*  50 */ "IfPos"            OpHelp("if r[P1]>0 then r[P1]-=P3, goto P2"),
+    /*  51 */ "IsNull"           OpHelp("if r[P1]==NULL goto P2"),
+    /*  52 */ "NotNull"          OpHelp("if r[P1]!=NULL goto P2"),
+    /*  53 */ "Ne"               OpHelp("IF r[P3]!=r[P1]"),
+    /*  54 */ "Eq"               OpHelp("IF r[P3]==r[P1]"),
+    /*  55 */ "Gt"               OpHelp("IF r[P3]>r[P1]"),
+    /*  56 */ "Le"               OpHelp("IF r[P3]<=r[P1]"),
+    /*  57 */ "Lt"               OpHelp("IF r[P3]<r[P1]"),
+    /*  58 */ "Ge"               OpHelp("IF r[P3]>=r[P1]"),
+    /*  59 */ "ElseEq"           OpHelp(""),
+    /*  60 */ "IfNotZero"        OpHelp("if r[P1]!=0 then r[P1]--, goto P2"),
+    /*  61 */ "DecrJumpZero"     OpHelp("if (--r[P1])==0 goto P2"),
+    /*  62 */ "IncrVacuum"       OpHelp(""),
+    /*  63 */ "VNext"            OpHelp(""),
+    /*  64 */ "Filter"           OpHelp("if key(P3@P4) not in filter(P1) goto P2"),
+    /*  65 */ "PureFunc"         OpHelp("r[P3]=func(r[P2@NP])"),
+    /*  66 */ "Function"         OpHelp("r[P3]=func(r[P2@NP])"),
+    /*  67 */ "Return"           OpHelp(""),
+    /*  68 */ "EndCoroutine"     OpHelp(""),
+    /*  69 */ "HaltIfNull"       OpHelp("if r[P3]=null halt"),
+    /*  70 */ "Halt"             OpHelp(""),
+    /*  71 */ "Integer"          OpHelp("r[P2]=P1"),
+    /*  72 */ "Int64"            OpHelp("r[P2]=P4"),
+    /*  73 */ "String"           OpHelp("r[P2]='P4' (len=P1)"),
+    /*  74 */ "BeginSubrtn"      OpHelp("r[P2]=NULL"),
+    /*  75 */ "Null"             OpHelp("r[P2..P3]=NULL"),
+    /*  76 */ "SoftNull"         OpHelp("r[P1]=NULL"),
+    /*  77 */ "Blob"             OpHelp("r[P2]=P4 (len=P1)"),
+    /*  78 */ "Variable"         OpHelp("r[P2]=parameter(P1)"),
+    /*  79 */ "Move"             OpHelp("r[P2@P3]=r[P1@P3]"),
+    /*  80 */ "Copy"             OpHelp("r[P2@P3+1]=r[P1@P3+1]"),
+    /*  81 */ "SCopy"            OpHelp("r[P2]=r[P1]"),
+    /*  82 */ "IntCopy"          OpHelp("r[P2]=r[P1]"),
+    /*  83 */ "FkCheck"          OpHelp(""),
+    /*  84 */ "ResultRow"        OpHelp("output=r[P1@P2]"),
+    /*  85 */ "CollSeq"          OpHelp(""),
+    /*  86 */ "AddImm"           OpHelp("r[P1]=r[P1]+P2"),
+    /*  87 */ "RealAffinity"     OpHelp(""),
+    /*  88 */ "Cast"             OpHelp("affinity(r[P1])"),
+    /*  89 */ "Permutation"      OpHelp(""),
+    /*  90 */ "Compare"          OpHelp("r[P1@P3] <-> r[P2@P3]"),
+    /*  91 */ "IsTrue"           OpHelp("r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4"),
+    /*  92 */ "ZeroOrNull"       OpHelp("r[P2] = 0 OR NULL"),
+    /*  93 */ "Offset"           OpHelp("r[P3] = sqlite_offset(P1)"),
+    /*  94 */ "Column"           OpHelp("r[P3]=PX cursor P1 column P2"),
+    /*  95 */ "TypeCheck"        OpHelp("typecheck(r[P1@P2])"),
+    /*  96 */ "Affinity"         OpHelp("affinity(r[P1@P2])"),
+    /*  97 */ "MakeRecord"       OpHelp("r[P3]=mkrec(r[P1@P2])"),
+    /*  98 */ "Count"            OpHelp("r[P2]=count()"),
+    /*  99 */ "ReadCookie"       OpHelp(""),
+    /* 100 */ "SetCookie"        OpHelp(""),
+    /* 101 */ "ReopenIdx"        OpHelp("root=P2 iDb=P3"),
+    /* 102 */ "OpenRead"         OpHelp("root=P2 iDb=P3"),
+    /* 103 */ "BitAnd"           OpHelp("r[P3]=r[P1]&r[P2]"),
+    /* 104 */ "BitOr"            OpHelp("r[P3]=r[P1]|r[P2]"),
+    /* 105 */ "ShiftLeft"        OpHelp("r[P3]=r[P2]<<r[P1]"),
+    /* 106 */ "ShiftRight"       OpHelp("r[P3]=r[P2]>>r[P1]"),
+    /* 107 */ "Add"              OpHelp("r[P3]=r[P1]+r[P2]"),
+    /* 108 */ "Subtract"         OpHelp("r[P3]=r[P2]-r[P1]"),
+    /* 109 */ "Multiply"         OpHelp("r[P3]=r[P1]*r[P2]"),
+    /* 110 */ "Divide"           OpHelp("r[P3]=r[P2]/r[P1]"),
+    /* 111 */ "Remainder"        OpHelp("r[P3]=r[P2]%r[P1]"),
+    /* 112 */ "Concat"           OpHelp("r[P3]=r[P2]+r[P1]"),
+    /* 113 */ "OpenWrite"        OpHelp("root=P2 iDb=P3"),
+    /* 114 */ "OpenDup"          OpHelp(""),
+    /* 115 */ "BitNot"           OpHelp("r[P2]= ~r[P1]"),
+    /* 116 */ "OpenAutoindex"    OpHelp("nColumn=P2"),
+    /* 117 */ "OpenEphemeral"    OpHelp("nColumn=P2"),
+    /* 118 */ "String8"          OpHelp("r[P2]='P4'"),
+    /* 119 */ "SorterOpen"       OpHelp(""),
+    /* 120 */ "SequenceTest"     OpHelp("if( cursor[P1].ctr++ ) pc = P2"),
+    /* 121 */ "OpenPseudo"       OpHelp("P3 columns in r[P2]"),
+    /* 122 */ "Close"            OpHelp(""),
+    /* 123 */ "ColumnsUsed"      OpHelp(""),
+    /* 124 */ "SeekScan"         OpHelp("Scan-ahead up to P1 rows"),
+    /* 125 */ "SeekHit"          OpHelp("set P2<=seekHit<=P3"),
+    /* 126 */ "Sequence"         OpHelp("r[P2]=cursor[P1].ctr++"),
+    /* 127 */ "NewRowid"         OpHelp("r[P2]=rowid"),
+    /* 128 */ "Insert"           OpHelp("intkey=r[P3] data=r[P2]"),
+    /* 129 */ "RowCell"          OpHelp(""),
+    /* 130 */ "Delete"           OpHelp(""),
+    /* 131 */ "ResetCount"       OpHelp(""),
+    /* 132 */ "SorterCompare"    OpHelp("if key(P1)!=trim(r[P3],P4) goto P2"),
+    /* 133 */ "SorterData"       OpHelp("r[P2]=data"),
+    /* 134 */ "RowData"          OpHelp("r[P2]=data"),
+    /* 135 */ "Rowid"            OpHelp("r[P2]=PX rowid of P1"),
+    /* 136 */ "NullRow"          OpHelp(""),
+    /* 137 */ "SeekEnd"          OpHelp(""),
+    /* 138 */ "IdxInsert"        OpHelp("key=r[P2]"),
+    /* 139 */ "SorterInsert"     OpHelp("key=r[P2]"),
+    /* 140 */ "IdxDelete"        OpHelp("key=r[P2@P3]"),
+    /* 141 */ "DeferredSeek"     OpHelp("Move P3 to P1.rowid if needed"),
+    /* 142 */ "IdxRowid"         OpHelp("r[P2]=rowid"),
+    /* 143 */ "FinishSeek"       OpHelp(""),
+    /* 144 */ "Destroy"          OpHelp(""),
+    /* 145 */ "Clear"            OpHelp(""),
+    /* 146 */ "ResetSorter"      OpHelp(""),
+    /* 147 */ "CreateBtree"      OpHelp("r[P2]=root iDb=P1 flags=P3"),
+    /* 148 */ "SqlExec"          OpHelp(""),
+    /* 149 */ "ParseSchema"      OpHelp(""),
+    /* 150 */ "LoadAnalysis"     OpHelp(""),
+    /* 151 */ "DropTable"        OpHelp(""),
+    /* 152 */ "DropIndex"        OpHelp(""),
+    /* 153 */ "DropTrigger"      OpHelp(""),
+    /* 154 */ "Real"             OpHelp("r[P2]=P4"),
+    /* 155 */ "IntegrityCk"      OpHelp(""),
+    /* 156 */ "RowSetAdd"        OpHelp("rowset(P1)=r[P2]"),
+    /* 157 */ "Param"            OpHelp(""),
+    /* 158 */ "FkCounter"        OpHelp("fkctr[P1]+=P2"),
+    /* 159 */ "MemMax"           OpHelp("r[P1]=max(r[P1],r[P2])"),
+    /* 160 */ "OffsetLimit"      OpHelp("if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1)"),
+    /* 161 */ "AggInverse"       OpHelp("accum=r[P3] inverse(r[P2@P5])"),
+    /* 162 */ "AggStep"          OpHelp("accum=r[P3] step(r[P2@P5])"),
+    /* 163 */ "AggStep1"         OpHelp("accum=r[P3] step(r[P2@P5])"),
+    /* 164 */ "AggValue"         OpHelp("r[P3]=value N=P2"),
+    /* 165 */ "AggFinal"         OpHelp("accum=r[P1] N=P2"),
+    /* 166 */ "Expire"           OpHelp(""),
+    /* 167 */ "CursorLock"       OpHelp(""),
+    /* 168 */ "CursorUnlock"     OpHelp(""),
+    /* 169 */ "TableLock"        OpHelp("iDb=P1 root=P2 write=P3"),
+    /* 170 */ "VBegin"           OpHelp(""),
+    /* 171 */ "VCreate"          OpHelp(""),
+    /* 172 */ "VDestroy"         OpHelp(""),
+    /* 173 */ "VOpen"            OpHelp(""),
+    /* 174 */ "VCheck"           OpHelp(""),
+    /* 175 */ "VInitIn"          OpHelp("r[P2]=ValueList(P1,P3)"),
+    /* 176 */ "VColumn"          OpHelp("r[P3]=vcolumn(P2)"),
+    /* 177 */ "VRename"          OpHelp(""),
+    /* 178 */ "Pagecount"        OpHelp(""),
+    /* 179 */ "MaxPgcnt"         OpHelp(""),
+    /* 180 */ "ClrSubtype"       OpHelp("r[P1].subtype = 0"),
+    /* 181 */ "GetSubtype"       OpHelp("r[P2] = r[P1].subtype"),
+    /* 182 */ "SetSubtype"       OpHelp("r[P2].subtype = r[P1]"),
+    /* 183 */ "FilterAdd"        OpHelp("filter(P1) += key(P3@P4)"),
+    /* 184 */ "Trace"            OpHelp(""),
+    /* 185 */ "CursorHint"       OpHelp(""),
+    /* 186 */ "ReleaseReg"       OpHelp("release r[P1@P2] mask P3"),
+    /* 187 */ "Noop"             OpHelp(""),
+    /* 188 */ "Explain"          OpHelp(""),
+    /* 189 */ "Abortable"        OpHelp(""),
+  };
+  return azName[i];
+}
+#endif
+
+/************** End of opcodes.c *********************************************/
+/************** Begin file os_kv.c *******************************************/
+/*
+** 2022-09-06
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains an experimental VFS layer that operates on a
+** Key/Value storage engine where both keys and values must be pure
+** text.
+*/
+/* #include <sqliteInt.h> */
+#if SQLITE_OS_KV || (SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL))
+
+/*****************************************************************************
+** Debugging logic
+*/
+
+/* SQLITE_KV_TRACE() is used for tracing calls to kvstorage routines. */
+#if 0
+#define SQLITE_KV_TRACE(X)  printf X
+#else
+#define SQLITE_KV_TRACE(X)
+#endif
+
+/* SQLITE_KV_LOG() is used for tracing calls to the VFS interface */
+#if 0
+#define SQLITE_KV_LOG(X)  printf X
+#else
+#define SQLITE_KV_LOG(X)
+#endif
+
+
+/*
+** Forward declaration of objects used by this VFS implementation
+*/
+typedef struct KVVfsFile KVVfsFile;
+
+/* A single open file.  There are only two files represented by this
+** VFS - the database and the rollback journal.
+*/
+struct KVVfsFile {
+  sqlite3_file base;              /* IO methods */
+  const char *zClass;             /* Storage class */
+  int isJournal;                  /* True if this is a journal file */
+  unsigned int nJrnl;             /* Space allocated for aJrnl[] */
+  char *aJrnl;                    /* Journal content */
+  int szPage;                     /* Last known page size */
+  sqlite3_int64 szDb;             /* Database file size.  -1 means unknown */
+  char *aData;                    /* Buffer to hold page data */
+};
+#define SQLITE_KVOS_SZ 133073
+
+/*
+** Methods for KVVfsFile
+*/
+static int kvvfsClose(sqlite3_file*);
+static int kvvfsReadDb(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int kvvfsReadJrnl(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int kvvfsWriteDb(sqlite3_file*,const void*,int iAmt, sqlite3_int64);
+static int kvvfsWriteJrnl(sqlite3_file*,const void*,int iAmt, sqlite3_int64);
+static int kvvfsTruncateDb(sqlite3_file*, sqlite3_int64 size);
+static int kvvfsTruncateJrnl(sqlite3_file*, sqlite3_int64 size);
+static int kvvfsSyncDb(sqlite3_file*, int flags);
+static int kvvfsSyncJrnl(sqlite3_file*, int flags);
+static int kvvfsFileSizeDb(sqlite3_file*, sqlite3_int64 *pSize);
+static int kvvfsFileSizeJrnl(sqlite3_file*, sqlite3_int64 *pSize);
+static int kvvfsLock(sqlite3_file*, int);
+static int kvvfsUnlock(sqlite3_file*, int);
+static int kvvfsCheckReservedLock(sqlite3_file*, int *pResOut);
+static int kvvfsFileControlDb(sqlite3_file*, int op, void *pArg);
+static int kvvfsFileControlJrnl(sqlite3_file*, int op, void *pArg);
+static int kvvfsSectorSize(sqlite3_file*);
+static int kvvfsDeviceCharacteristics(sqlite3_file*);
+
+/*
+** Methods for sqlite3_vfs
+*/
+static int kvvfsOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
+static int kvvfsDelete(sqlite3_vfs*, const char *zName, int syncDir);
+static int kvvfsAccess(sqlite3_vfs*, const char *zName, int flags, int *);
+static int kvvfsFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
+static void *kvvfsDlOpen(sqlite3_vfs*, const char *zFilename);
+static int kvvfsRandomness(sqlite3_vfs*, int nByte, char *zOut);
+static int kvvfsSleep(sqlite3_vfs*, int microseconds);
+static int kvvfsCurrentTime(sqlite3_vfs*, double*);
+static int kvvfsCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
+
+static sqlite3_vfs sqlite3OsKvvfsObject = {
+  1,                              /* iVersion */
+  sizeof(KVVfsFile),              /* szOsFile */
+  1024,                           /* mxPathname */
+  0,                              /* pNext */
+  "kvvfs",                        /* zName */
+  0,                              /* pAppData */
+  kvvfsOpen,                      /* xOpen */
+  kvvfsDelete,                    /* xDelete */
+  kvvfsAccess,                    /* xAccess */
+  kvvfsFullPathname,              /* xFullPathname */
+  kvvfsDlOpen,                    /* xDlOpen */
+  0,                              /* xDlError */
+  0,                              /* xDlSym */
+  0,                              /* xDlClose */
+  kvvfsRandomness,                /* xRandomness */
+  kvvfsSleep,                     /* xSleep */
+  kvvfsCurrentTime,               /* xCurrentTime */
+  0,                              /* xGetLastError */
+  kvvfsCurrentTimeInt64           /* xCurrentTimeInt64 */
+};
+
+/* Methods for sqlite3_file objects referencing a database file
+*/
+static sqlite3_io_methods kvvfs_db_io_methods = {
+  1,                              /* iVersion */
+  kvvfsClose,                     /* xClose */
+  kvvfsReadDb,                    /* xRead */
+  kvvfsWriteDb,                   /* xWrite */
+  kvvfsTruncateDb,                /* xTruncate */
+  kvvfsSyncDb,                    /* xSync */
+  kvvfsFileSizeDb,                /* xFileSize */
+  kvvfsLock,                      /* xLock */
+  kvvfsUnlock,                    /* xUnlock */
+  kvvfsCheckReservedLock,         /* xCheckReservedLock */
+  kvvfsFileControlDb,             /* xFileControl */
+  kvvfsSectorSize,                /* xSectorSize */
+  kvvfsDeviceCharacteristics,     /* xDeviceCharacteristics */
+  0,                              /* xShmMap */
+  0,                              /* xShmLock */
+  0,                              /* xShmBarrier */
+  0,                              /* xShmUnmap */
+  0,                              /* xFetch */
+  0                               /* xUnfetch */
+};
+
+/* Methods for sqlite3_file objects referencing a rollback journal
+*/
+static sqlite3_io_methods kvvfs_jrnl_io_methods = {
+  1,                              /* iVersion */
+  kvvfsClose,                     /* xClose */
+  kvvfsReadJrnl,                  /* xRead */
+  kvvfsWriteJrnl,                 /* xWrite */
+  kvvfsTruncateJrnl,              /* xTruncate */
+  kvvfsSyncJrnl,                  /* xSync */
+  kvvfsFileSizeJrnl,              /* xFileSize */
+  kvvfsLock,                      /* xLock */
+  kvvfsUnlock,                    /* xUnlock */
+  kvvfsCheckReservedLock,         /* xCheckReservedLock */
+  kvvfsFileControlJrnl,           /* xFileControl */
+  kvvfsSectorSize,                /* xSectorSize */
+  kvvfsDeviceCharacteristics,     /* xDeviceCharacteristics */
+  0,                              /* xShmMap */
+  0,                              /* xShmLock */
+  0,                              /* xShmBarrier */
+  0,                              /* xShmUnmap */
+  0,                              /* xFetch */
+  0                               /* xUnfetch */
+};
+
+/****** Storage subsystem **************************************************/
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+/* Forward declarations for the low-level storage engine
+*/
+static int kvstorageWrite(const char*, const char *zKey, const char *zData);
+static int kvstorageDelete(const char*, const char *zKey);
+static int kvstorageRead(const char*, const char *zKey, char *zBuf, int nBuf);
+#define KVSTORAGE_KEY_SZ  32
+
+/* Expand the key name with an appropriate prefix and put the result
+** zKeyOut[].  The zKeyOut[] buffer is assumed to hold at least
+** KVSTORAGE_KEY_SZ bytes.
+*/
+static void kvstorageMakeKey(
+  const char *zClass,
+  const char *zKeyIn,
+  char *zKeyOut
+){
+  sqlite3_snprintf(KVSTORAGE_KEY_SZ, zKeyOut, "kvvfs-%s-%s", zClass, zKeyIn);
+}
+
+/* Write content into a key.  zClass is the particular namespace of the
+** underlying key/value store to use - either "local" or "session".
+**
+** Both zKey and zData are zero-terminated pure text strings.
+**
+** Return the number of errors.
+*/
+static int kvstorageWrite(
+  const char *zClass,
+  const char *zKey,
+  const char *zData
+){
+  FILE *fd;
+  char zXKey[KVSTORAGE_KEY_SZ];
+  kvstorageMakeKey(zClass, zKey, zXKey);
+  fd = fopen(zXKey, "wb");
+  if( fd ){
+    SQLITE_KV_TRACE(("KVVFS-WRITE  %-15s (%d) %.50s%s\n", zXKey,
+                 (int)strlen(zData), zData,
+                 strlen(zData)>50 ? "..." : ""));
+    fputs(zData, fd);
+    fclose(fd);
+    return 0;
+  }else{
+    return 1;
+  }
+}
+
+/* Delete a key (with its corresponding data) from the key/value
+** namespace given by zClass.  If the key does not previously exist,
+** this routine is a no-op.
+*/
+static int kvstorageDelete(const char *zClass, const char *zKey){
+  char zXKey[KVSTORAGE_KEY_SZ];
+  kvstorageMakeKey(zClass, zKey, zXKey);
+  unlink(zXKey);
+  SQLITE_KV_TRACE(("KVVFS-DELETE %-15s\n", zXKey));
+  return 0;
+}
+
+/* Read the value associated with a zKey from the key/value namespace given
+** by zClass and put the text data associated with that key in the first
+** nBuf bytes of zBuf[].  The value might be truncated if zBuf is not large
+** enough to hold it all.  The value put into zBuf must always be zero
+** terminated, even if it gets truncated because nBuf is not large enough.
+**
+** Return the total number of bytes in the data, without truncation, and
+** not counting the final zero terminator.   Return -1 if the key does
+** not exist.
+**
+** If nBuf<=0 then this routine simply returns the size of the data without
+** actually reading it.
+*/
+static int kvstorageRead(
+  const char *zClass,
+  const char *zKey,
+  char *zBuf,
+  int nBuf
+){
+  FILE *fd;
+  struct stat buf;
+  char zXKey[KVSTORAGE_KEY_SZ];
+  kvstorageMakeKey(zClass, zKey, zXKey);
+  if( access(zXKey, R_OK)!=0
+   || stat(zXKey, &buf)!=0
+   || !S_ISREG(buf.st_mode)
+  ){
+    SQLITE_KV_TRACE(("KVVFS-READ   %-15s (-1)\n", zXKey));
+    return -1;
+  }
+  if( nBuf<=0 ){
+    return (int)buf.st_size;
+  }else if( nBuf==1 ){
+    zBuf[0] = 0;
+    SQLITE_KV_TRACE(("KVVFS-READ   %-15s (%d)\n", zXKey,
+                 (int)buf.st_size));
+    return (int)buf.st_size;
+  }
+  if( nBuf > buf.st_size + 1 ){
+    nBuf = buf.st_size + 1;
+  }
+  fd = fopen(zXKey, "rb");
+  if( fd==0 ){
+    SQLITE_KV_TRACE(("KVVFS-READ   %-15s (-1)\n", zXKey));
+    return -1;
+  }else{
+    sqlite3_int64 n = fread(zBuf, 1, nBuf-1, fd);
+    fclose(fd);
+    zBuf[n] = 0;
+    SQLITE_KV_TRACE(("KVVFS-READ   %-15s (%lld) %.50s%s\n", zXKey,
+                 n, zBuf, n>50 ? "..." : ""));
+    return (int)n;
+  }
+}
+
+/*
+** An internal level of indirection which enables us to replace the
+** kvvfs i/o methods with JavaScript implementations in WASM builds.
+** Maintenance reminder: if this struct changes in any way, the JSON
+** rendering of its structure must be updated in
+** sqlite3_wasm_enum_json(). There are no binary compatibility
+** concerns, so it does not need an iVersion member. This file is
+** necessarily always compiled together with sqlite3_wasm_enum_json(),
+** and JS code dynamically creates the mapping of members based on
+** that JSON description.
+*/
+typedef struct sqlite3_kvvfs_methods sqlite3_kvvfs_methods;
+struct sqlite3_kvvfs_methods {
+  int (*xRead)(const char *zClass, const char *zKey, char *zBuf, int nBuf);
+  int (*xWrite)(const char *zClass, const char *zKey, const char *zData);
+  int (*xDelete)(const char *zClass, const char *zKey);
+  const int nKeySize;
+};
+
+/*
+** This object holds the kvvfs I/O methods which may be swapped out
+** for JavaScript-side implementations in WASM builds. In such builds
+** it cannot be const, but in native builds it should be so that
+** the compiler can hopefully optimize this level of indirection out.
+** That said, kvvfs is intended primarily for use in WASM builds.
+**
+** Note that this is not explicitly flagged as static because the
+** amalgamation build will tag it with SQLITE_PRIVATE.
+*/
+#ifndef SQLITE_WASM
+const
+#endif
+SQLITE_PRIVATE sqlite3_kvvfs_methods sqlite3KvvfsMethods = {
+kvstorageRead,
+kvstorageWrite,
+kvstorageDelete,
+KVSTORAGE_KEY_SZ
+};
+
+/****** Utility subroutines ************************************************/
+
+/*
+** Encode binary into the text encoded used to persist on disk.
+** The output text is stored in aOut[], which must be at least
+** nData+1 bytes in length.
+**
+** Return the actual length of the encoded text, not counting the
+** zero terminator at the end.
+**
+** Encoding format
+** ---------------
+**
+**   *  Non-zero bytes are encoded as upper-case hexadecimal
+**
+**   *  A sequence of one or more zero-bytes that are not at the
+**      beginning of the buffer are encoded as a little-endian
+**      base-26 number using a..z.  "a" means 0.  "b" means 1,
+**      "z" means 25.  "ab" means 26.  "ac" means 52.  And so forth.
+**
+**   *  Because there is no overlap between the encoding characters
+**      of hexadecimal and base-26 numbers, it is always clear where
+**      one stops and the next begins.
+*/
+static int kvvfsEncode(const char *aData, int nData, char *aOut){
+  int i, j;
+  const unsigned char *a = (const unsigned char*)aData;
+  for(i=j=0; i<nData; i++){
+    unsigned char c = a[i];
+    if( c!=0 ){
+      aOut[j++] = "0123456789ABCDEF"[c>>4];
+      aOut[j++] = "0123456789ABCDEF"[c&0xf];
+    }else{
+      /* A sequence of 1 or more zeros is stored as a little-endian
+      ** base-26 number using a..z as the digits. So one zero is "b".
+      ** Two zeros is "c". 25 zeros is "z", 26 zeros is "ab", 27 is "bb",
+      ** and so forth.
+      */
+      int k;
+      for(k=1; i+k<nData && a[i+k]==0; k++){}
+      i += k-1;
+      while( k>0 ){
+        aOut[j++] = 'a'+(k%26);
+        k /= 26;
+      }
+    }
+  }
+  aOut[j] = 0;
+  return j;
+}
+
+static const signed char kvvfsHexValue[256] = {
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+   0,  1,  2,  3,  4,  5,  6,  7,    8,  9, -1, -1, -1, -1, -1, -1,
+  -1, 10, 11, 12, 13, 14, 15, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1
+};
+
+/*
+** Decode the text encoding back to binary.  The binary content is
+** written into pOut, which must be at least nOut bytes in length.
+**
+** The return value is the number of bytes actually written into aOut[].
+*/
+static int kvvfsDecode(const char *a, char *aOut, int nOut){
+  int i, j;
+  int c;
+  const unsigned char *aIn = (const unsigned char*)a;
+  i = 0;
+  j = 0;
+  while( 1 ){
+    c = kvvfsHexValue[aIn[i]];
+    if( c<0 ){
+      int n = 0;
+      int mult = 1;
+      c = aIn[i];
+      if( c==0 ) break;
+      while( c>='a' && c<='z' ){
+        n += (c - 'a')*mult;
+        mult *= 26;
+        c = aIn[++i];
+      }
+      if( j+n>nOut ) return -1;
+      memset(&aOut[j], 0, n);
+      j += n;
+      if( c==0 || mult==1 ) break; /* progress stalled if mult==1 */
+    }else{
+      aOut[j] = c<<4;
+      c = kvvfsHexValue[aIn[++i]];
+      if( c<0 ) break;
+      aOut[j++] += c;
+      i++;
+    }
+  }
+  return j;
+}
+
+/*
+** Decode a complete journal file.  Allocate space in pFile->aJrnl
+** and store the decoding there.  Or leave pFile->aJrnl set to NULL
+** if an error is encountered.
+**
+** The first few characters of the text encoding will be a little-endian
+** base-26 number (digits a..z) that is the total number of bytes
+** in the decoded journal file image.  This base-26 number is followed
+** by a single space, then the encoding of the journal.  The space
+** separator is required to act as a terminator for the base-26 number.
+*/
+static void kvvfsDecodeJournal(
+  KVVfsFile *pFile,      /* Store decoding in pFile->aJrnl */
+  const char *zTxt,      /* Text encoding.  Zero-terminated */
+  int nTxt               /* Bytes in zTxt, excluding zero terminator */
+){
+  unsigned int n = 0;
+  int c, i, mult;
+  i = 0;
+  mult = 1;
+  while( (c = zTxt[i++])>='a' && c<='z' ){
+    n += (zTxt[i] - 'a')*mult;
+    mult *= 26;
+  }
+  sqlite3_free(pFile->aJrnl);
+  pFile->aJrnl = sqlite3_malloc64( n );
+  if( pFile->aJrnl==0 ){
+    pFile->nJrnl = 0;
+    return;
+  }
+  pFile->nJrnl = n;
+  n = kvvfsDecode(zTxt+i, pFile->aJrnl, pFile->nJrnl);
+  if( n<pFile->nJrnl ){
+    sqlite3_free(pFile->aJrnl);
+    pFile->aJrnl = 0;
+    pFile->nJrnl = 0;
+  }
+}
+
+/*
+** Read or write the "sz" element, containing the database file size.
+*/
+static sqlite3_int64 kvvfsReadFileSize(KVVfsFile *pFile){
+  char zData[50];
+  zData[0] = 0;
+  sqlite3KvvfsMethods.xRead(pFile->zClass, "sz", zData, sizeof(zData)-1);
+  return strtoll(zData, 0, 0);
+}
+static int kvvfsWriteFileSize(KVVfsFile *pFile, sqlite3_int64 sz){
+  char zData[50];
+  sqlite3_snprintf(sizeof(zData), zData, "%lld", sz);
+  return sqlite3KvvfsMethods.xWrite(pFile->zClass, "sz", zData);
+}
+
+/****** sqlite3_io_methods methods ******************************************/
+
+/*
+** Close an kvvfs-file.
+*/
+static int kvvfsClose(sqlite3_file *pProtoFile){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+
+  SQLITE_KV_LOG(("xClose %s %s\n", pFile->zClass,
+             pFile->isJournal ? "journal" : "db"));
+  sqlite3_free(pFile->aJrnl);
+  sqlite3_free(pFile->aData);
+  return SQLITE_OK;
+}
+
+/*
+** Read from the -journal file.
+*/
+static int kvvfsReadJrnl(
+  sqlite3_file *pProtoFile,
+  void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  assert( pFile->isJournal );
+  SQLITE_KV_LOG(("xRead('%s-journal',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+  if( pFile->aJrnl==0 ){
+    int szTxt = kvstorageRead(pFile->zClass, "jrnl", 0, 0);
+    char *aTxt;
+    if( szTxt<=4 ){
+      return SQLITE_IOERR;
+    }
+    aTxt = sqlite3_malloc64( szTxt+1 );
+    if( aTxt==0 ) return SQLITE_NOMEM;
+    kvstorageRead(pFile->zClass, "jrnl", aTxt, szTxt+1);
+    kvvfsDecodeJournal(pFile, aTxt, szTxt);
+    sqlite3_free(aTxt);
+    if( pFile->aJrnl==0 ) return SQLITE_IOERR;
+  }
+  if( iOfst+iAmt>pFile->nJrnl ){
+    return SQLITE_IOERR_SHORT_READ;
+  }
+  memcpy(zBuf, pFile->aJrnl+iOfst, iAmt);
+  return SQLITE_OK;
+}
+
+/*
+** Read from the database file.
+*/
+static int kvvfsReadDb(
+  sqlite3_file *pProtoFile,
+  void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  unsigned int pgno;
+  int got, n;
+  char zKey[30];
+  char *aData = pFile->aData;
+  assert( iOfst>=0 );
+  assert( iAmt>=0 );
+  SQLITE_KV_LOG(("xRead('%s-db',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+  if( iOfst+iAmt>=512 ){
+    if( (iOfst % iAmt)!=0 ){
+      return SQLITE_IOERR_READ;
+    }
+    if( (iAmt & (iAmt-1))!=0 || iAmt<512 || iAmt>65536 ){
+      return SQLITE_IOERR_READ;
+    }
+    pFile->szPage = iAmt;
+    pgno = 1 + iOfst/iAmt;
+  }else{
+    pgno = 1;
+  }
+  sqlite3_snprintf(sizeof(zKey), zKey, "%u", pgno);
+  got = sqlite3KvvfsMethods.xRead(pFile->zClass, zKey,
+                                  aData, SQLITE_KVOS_SZ-1);
+  if( got<0 ){
+    n = 0;
+  }else{
+    aData[got] = 0;
+    if( iOfst+iAmt<512 ){
+      int k = iOfst+iAmt;
+      aData[k*2] = 0;
+      n = kvvfsDecode(aData, &aData[2000], SQLITE_KVOS_SZ-2000);
+      if( n>=iOfst+iAmt ){
+        memcpy(zBuf, &aData[2000+iOfst], iAmt);
+        n = iAmt;
+      }else{
+        n = 0;
+      }
+    }else{
+      n = kvvfsDecode(aData, zBuf, iAmt);
+    }
+  }
+  if( n<iAmt ){
+    memset(zBuf+n, 0, iAmt-n);
+    return SQLITE_IOERR_SHORT_READ;
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** Write into the -journal file.
+*/
+static int kvvfsWriteJrnl(
+  sqlite3_file *pProtoFile,
+  const void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  sqlite3_int64 iEnd = iOfst+iAmt;
+  SQLITE_KV_LOG(("xWrite('%s-journal',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+  if( iEnd>=0x10000000 ) return SQLITE_FULL;
+  if( pFile->aJrnl==0 || pFile->nJrnl<iEnd ){
+    char *aNew = sqlite3_realloc(pFile->aJrnl, iEnd);
+    if( aNew==0 ){
+      return SQLITE_IOERR_NOMEM;
+    }
+    pFile->aJrnl = aNew;
+    if( pFile->nJrnl<iOfst ){
+      memset(pFile->aJrnl+pFile->nJrnl, 0, iOfst-pFile->nJrnl);
+    }
+    pFile->nJrnl = iEnd;
+  }
+  memcpy(pFile->aJrnl+iOfst, zBuf, iAmt);
+  return SQLITE_OK;
+}
+
+/*
+** Write into the database file.
+*/
+static int kvvfsWriteDb(
+  sqlite3_file *pProtoFile,
+  const void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  unsigned int pgno;
+  char zKey[30];
+  char *aData = pFile->aData;
+  SQLITE_KV_LOG(("xWrite('%s-db',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+  assert( iAmt>=512 && iAmt<=65536 );
+  assert( (iAmt & (iAmt-1))==0 );
+  assert( pFile->szPage<0 || pFile->szPage==iAmt );
+  pFile->szPage = iAmt;
+  pgno = 1 + iOfst/iAmt;
+  sqlite3_snprintf(sizeof(zKey), zKey, "%u", pgno);
+  kvvfsEncode(zBuf, iAmt, aData);
+  if( sqlite3KvvfsMethods.xWrite(pFile->zClass, zKey, aData) ){
+    return SQLITE_IOERR;
+  }
+  if( iOfst+iAmt > pFile->szDb ){
+    pFile->szDb = iOfst + iAmt;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Truncate an kvvfs-file.
+*/
+static int kvvfsTruncateJrnl(sqlite3_file *pProtoFile, sqlite_int64 size){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  SQLITE_KV_LOG(("xTruncate('%s-journal',%lld)\n", pFile->zClass, size));
+  assert( size==0 );
+  sqlite3KvvfsMethods.xDelete(pFile->zClass, "jrnl");
+  sqlite3_free(pFile->aJrnl);
+  pFile->aJrnl = 0;
+  pFile->nJrnl = 0;
+  return SQLITE_OK;
+}
+static int kvvfsTruncateDb(sqlite3_file *pProtoFile, sqlite_int64 size){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  if( pFile->szDb>size
+   && pFile->szPage>0
+   && (size % pFile->szPage)==0
+  ){
+    char zKey[50];
+    unsigned int pgno, pgnoMax;
+    SQLITE_KV_LOG(("xTruncate('%s-db',%lld)\n", pFile->zClass, size));
+    pgno = 1 + size/pFile->szPage;
+    pgnoMax = 2 + pFile->szDb/pFile->szPage;
+    while( pgno<=pgnoMax ){
+      sqlite3_snprintf(sizeof(zKey), zKey, "%u", pgno);
+      sqlite3KvvfsMethods.xDelete(pFile->zClass, zKey);
+      pgno++;
+    }
+    pFile->szDb = size;
+    return kvvfsWriteFileSize(pFile, size) ? SQLITE_IOERR : SQLITE_OK;
+  }
+  return SQLITE_IOERR;
+}
+
+/*
+** Sync an kvvfs-file.
+*/
+static int kvvfsSyncJrnl(sqlite3_file *pProtoFile, int flags){
+  int i, n;
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  char *zOut;
+  SQLITE_KV_LOG(("xSync('%s-journal')\n", pFile->zClass));
+  if( pFile->nJrnl<=0 ){
+    return kvvfsTruncateJrnl(pProtoFile, 0);
+  }
+  zOut = sqlite3_malloc64( pFile->nJrnl*2 + 50 );
+  if( zOut==0 ){
+    return SQLITE_IOERR_NOMEM;
+  }
+  n = pFile->nJrnl;
+  i = 0;
+  do{
+    zOut[i++] = 'a' + (n%26);
+    n /= 26;
+  }while( n>0 );
+  zOut[i++] = ' ';
+  kvvfsEncode(pFile->aJrnl, pFile->nJrnl, &zOut[i]);
+  i = sqlite3KvvfsMethods.xWrite(pFile->zClass, "jrnl", zOut);
+  sqlite3_free(zOut);
+  return i ? SQLITE_IOERR : SQLITE_OK;
+}
+static int kvvfsSyncDb(sqlite3_file *pProtoFile, int flags){
+  return SQLITE_OK;
+}
+
+/*
+** Return the current file-size of an kvvfs-file.
+*/
+static int kvvfsFileSizeJrnl(sqlite3_file *pProtoFile, sqlite_int64 *pSize){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  SQLITE_KV_LOG(("xFileSize('%s-journal')\n", pFile->zClass));
+  *pSize = pFile->nJrnl;
+  return SQLITE_OK;
+}
+static int kvvfsFileSizeDb(sqlite3_file *pProtoFile, sqlite_int64 *pSize){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  SQLITE_KV_LOG(("xFileSize('%s-db')\n", pFile->zClass));
+  if( pFile->szDb>=0 ){
+    *pSize = pFile->szDb;
+  }else{
+    *pSize = kvvfsReadFileSize(pFile);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Lock an kvvfs-file.
+*/
+static int kvvfsLock(sqlite3_file *pProtoFile, int eLock){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  assert( !pFile->isJournal );
+  SQLITE_KV_LOG(("xLock(%s,%d)\n", pFile->zClass, eLock));
+
+  if( eLock!=SQLITE_LOCK_NONE ){
+    pFile->szDb = kvvfsReadFileSize(pFile);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Unlock an kvvfs-file.
+*/
+static int kvvfsUnlock(sqlite3_file *pProtoFile, int eLock){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  assert( !pFile->isJournal );
+  SQLITE_KV_LOG(("xUnlock(%s,%d)\n", pFile->zClass, eLock));
+  if( eLock==SQLITE_LOCK_NONE ){
+    pFile->szDb = -1;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on an kvvfs-file.
+*/
+static int kvvfsCheckReservedLock(sqlite3_file *pProtoFile, int *pResOut){
+  SQLITE_KV_LOG(("xCheckReservedLock\n"));
+  *pResOut = 0;
+  return SQLITE_OK;
+}
+
+/*
+** File control method. For custom operations on an kvvfs-file.
+*/
+static int kvvfsFileControlJrnl(sqlite3_file *pProtoFile, int op, void *pArg){
+  SQLITE_KV_LOG(("xFileControl(%d) on journal\n", op));
+  return SQLITE_NOTFOUND;
+}
+static int kvvfsFileControlDb(sqlite3_file *pProtoFile, int op, void *pArg){
+  SQLITE_KV_LOG(("xFileControl(%d) on database\n", op));
+  if( op==SQLITE_FCNTL_SYNC ){
+    KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+    int rc = SQLITE_OK;
+    SQLITE_KV_LOG(("xSync('%s-db')\n", pFile->zClass));
+    if( pFile->szDb>0 && 0!=kvvfsWriteFileSize(pFile, pFile->szDb) ){
+      rc = SQLITE_IOERR;
+    }
+    return rc;
+  }
+  return SQLITE_NOTFOUND;
+}
+
+/*
+** Return the sector-size in bytes for an kvvfs-file.
+*/
+static int kvvfsSectorSize(sqlite3_file *pFile){
+  return 512;
+}
+
+/*
+** Return the device characteristic flags supported by an kvvfs-file.
+*/
+static int kvvfsDeviceCharacteristics(sqlite3_file *pProtoFile){
+  return 0;
+}
+
+/****** sqlite3_vfs methods *************************************************/
+
+/*
+** Open an kvvfs file handle.
+*/
+static int kvvfsOpen(
+  sqlite3_vfs *pProtoVfs,
+  const char *zName,
+  sqlite3_file *pProtoFile,
+  int flags,
+  int *pOutFlags
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  if( zName==0 ) zName = "";
+  SQLITE_KV_LOG(("xOpen(\"%s\")\n", zName));
+  if( strcmp(zName, "local")==0
+   || strcmp(zName, "session")==0
+  ){
+    pFile->isJournal = 0;
+    pFile->base.pMethods = &kvvfs_db_io_methods;
+  }else
+  if( strcmp(zName, "local-journal")==0
+   || strcmp(zName, "session-journal")==0
+  ){
+    pFile->isJournal = 1;
+    pFile->base.pMethods = &kvvfs_jrnl_io_methods;
+  }else{
+    return SQLITE_CANTOPEN;
+  }
+  if( zName[0]=='s' ){
+    pFile->zClass = "session";
+  }else{
+    pFile->zClass = "local";
+  }
+  pFile->aData = sqlite3_malloc64(SQLITE_KVOS_SZ);
+  if( pFile->aData==0 ){
+    return SQLITE_NOMEM;
+  }
+  pFile->aJrnl = 0;
+  pFile->nJrnl = 0;
+  pFile->szPage = -1;
+  pFile->szDb = -1;
+  return SQLITE_OK;
+}
+
+/*
+** Delete the file located at zPath. If the dirSync argument is true,
+** ensure the file-system modifications are synced to disk before
+** returning.
+*/
+static int kvvfsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  if( strcmp(zPath, "local-journal")==0 ){
+    sqlite3KvvfsMethods.xDelete("local", "jrnl");
+  }else
+  if( strcmp(zPath, "session-journal")==0 ){
+    sqlite3KvvfsMethods.xDelete("session", "jrnl");
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Test for access permissions. Return true if the requested permission
+** is available, or false otherwise.
+*/
+static int kvvfsAccess(
+  sqlite3_vfs *pProtoVfs,
+  const char *zPath,
+  int flags,
+  int *pResOut
+){
+  SQLITE_KV_LOG(("xAccess(\"%s\")\n", zPath));
+  if( strcmp(zPath, "local-journal")==0 ){
+    *pResOut = sqlite3KvvfsMethods.xRead("local", "jrnl", 0, 0)>0;
+  }else
+  if( strcmp(zPath, "session-journal")==0 ){
+    *pResOut = sqlite3KvvfsMethods.xRead("session", "jrnl", 0, 0)>0;
+  }else
+  if( strcmp(zPath, "local")==0 ){
+    *pResOut = sqlite3KvvfsMethods.xRead("local", "sz", 0, 0)>0;
+  }else
+  if( strcmp(zPath, "session")==0 ){
+    *pResOut = sqlite3KvvfsMethods.xRead("session", "sz", 0, 0)>0;
+  }else
+  {
+    *pResOut = 0;
+  }
+  SQLITE_KV_LOG(("xAccess returns %d\n",*pResOut));
+  return SQLITE_OK;
+}
+
+/*
+** Populate buffer zOut with the full canonical pathname corresponding
+** to the pathname in zPath. zOut is guaranteed to point to a buffer
+** of at least (INST_MAX_PATHNAME+1) bytes.
+*/
+static int kvvfsFullPathname(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int nOut,
+  char *zOut
+){
+  size_t nPath;
+#ifdef SQLITE_OS_KV_ALWAYS_LOCAL
+  zPath = "local";
+#endif
+  nPath = strlen(zPath);
+  SQLITE_KV_LOG(("xFullPathname(\"%s\")\n", zPath));
+  if( nOut<nPath+1 ) nPath = nOut - 1;
+  memcpy(zOut, zPath, nPath);
+  zOut[nPath] = 0;
+  return SQLITE_OK;
+}
+
+/*
+** Open the dynamic library located at zPath and return a handle.
+*/
+static void *kvvfsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  return 0;
+}
+
+/*
+** Populate the buffer pointed to by zBufOut with nByte bytes of
+** random data.
+*/
+static int kvvfsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  memset(zBufOut, 0, nByte);
+  return nByte;
+}
+
+/*
+** Sleep for nMicro microseconds. Return the number of microseconds
+** actually slept.
+*/
+static int kvvfsSleep(sqlite3_vfs *pVfs, int nMicro){
+  return SQLITE_OK;
+}
+
+/*
+** Return the current time as a Julian Day number in *pTimeOut.
+*/
+static int kvvfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+  sqlite3_int64 i = 0;
+  int rc;
+  rc = kvvfsCurrentTimeInt64(0, &i);
+  *pTimeOut = i/86400000.0;
+  return rc;
+}
+#include <sys/time.h>
+static int kvvfsCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
+  static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+  struct timeval sNow;
+  (void)gettimeofday(&sNow, 0);  /* Cannot fail given valid arguments */
+  *pTimeOut = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_usec/1000;
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OS_KV || SQLITE_OS_UNIX */
+
+#if SQLITE_OS_KV
+/*
+** This routine is called initialize the KV-vfs as the default VFS.
+*/
+SQLITE_API int sqlite3_os_init(void){
+  return sqlite3_vfs_register(&sqlite3OsKvvfsObject, 1);
+}
+SQLITE_API int sqlite3_os_end(void){
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OS_KV */
+
+#if SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL)
+SQLITE_PRIVATE int sqlite3KvvfsInit(void){
+  return sqlite3_vfs_register(&sqlite3OsKvvfsObject, 0);
+}
+#endif
+
+/************** End of os_kv.c ***********************************************/
+/************** Begin file os_unix.c *****************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains the VFS implementation for unix-like operating systems
+** include Linux, MacOSX, *BSD, QNX, VxWorks, AIX, HPUX, and others.
+**
+** There are actually several different VFS implementations in this file.
+** The differences are in the way that file locking is done.  The default
+** implementation uses Posix Advisory Locks.  Alternative implementations
+** use flock(), dot-files, various proprietary locking schemas, or simply
+** skip locking all together.
+**
+** This source file is organized into divisions where the logic for various
+** subfunctions is contained within the appropriate division.  PLEASE
+** KEEP THE STRUCTURE OF THIS FILE INTACT.  New code should be placed
+** in the correct division and should be clearly labelled.
+**
+** The layout of divisions is as follows:
+**
+**   *  General-purpose declarations and utility functions.
+**   *  Unique file ID logic used by VxWorks.
+**   *  Various locking primitive implementations (all except proxy locking):
+**      + for Posix Advisory Locks
+**      + for no-op locks
+**      + for dot-file locks
+**      + for flock() locking
+**      + for named semaphore locks (VxWorks only)
+**      + for AFP filesystem locks (MacOSX only)
+**   *  sqlite3_file methods not associated with locking.
+**   *  Definitions of sqlite3_io_methods objects for all locking
+**      methods plus "finder" functions for each locking method.
+**   *  sqlite3_vfs method implementations.
+**   *  Locking primitives for the proxy uber-locking-method. (MacOSX only)
+**   *  Definitions of sqlite3_vfs objects for all locking methods
+**      plus implementations of sqlite3_os_init() and sqlite3_os_end().
+*/
+/* #include "sqliteInt.h" */
+#if SQLITE_OS_UNIX              /* This file is used on unix only */
+
+/*
+** There are various methods for file locking used for concurrency
+** control:
+**
+**   1. POSIX locking (the default),
+**   2. No locking,
+**   3. Dot-file locking,
+**   4. flock() locking,
+**   5. AFP locking (OSX only),
+**   6. Named POSIX semaphores (VXWorks only),
+**   7. proxy locking. (OSX only)
+**
+** Styles 4, 5, and 7 are only available of SQLITE_ENABLE_LOCKING_STYLE
+** is defined to 1.  The SQLITE_ENABLE_LOCKING_STYLE also enables automatic
+** selection of the appropriate locking style based on the filesystem
+** where the database is located.
+*/
+#if !defined(SQLITE_ENABLE_LOCKING_STYLE)
+#  if defined(__APPLE__)
+#    define SQLITE_ENABLE_LOCKING_STYLE 1
+#  else
+#    define SQLITE_ENABLE_LOCKING_STYLE 0
+#  endif
+#endif
+
+/* Use pread() and pwrite() if they are available */
+#if defined(__APPLE__) || defined(__linux__)
+# define HAVE_PREAD 1
+# define HAVE_PWRITE 1
+#endif
+#if defined(HAVE_PREAD64) && defined(HAVE_PWRITE64)
+# undef USE_PREAD
+# define USE_PREAD64 1
+#elif defined(HAVE_PREAD) && defined(HAVE_PWRITE)
+# undef USE_PREAD64
+# define USE_PREAD 1
+#endif
+
+/*
+** standard include files.
+*/
+#include <sys/types.h>   /* amalgamator: keep */
+#include <sys/stat.h>    /* amalgamator: keep */
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <unistd.h>      /* amalgamator: keep */
+/* #include <time.h> */
+#include <sys/time.h>    /* amalgamator: keep */
+#include <errno.h>
+#if (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0) \
+  && !defined(SQLITE_WASI)
+# include <sys/mman.h>
+#endif
+
+#if SQLITE_ENABLE_LOCKING_STYLE
+/* # include <sys/ioctl.h> */
+# include <sys/file.h>
+# include <sys/param.h>
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+/*
+** Try to determine if gethostuuid() is available based on standard
+** macros.  This might sometimes compute the wrong value for some
+** obscure platforms.  For those cases, simply compile with one of
+** the following:
+**
+**    -DHAVE_GETHOSTUUID=0
+**    -DHAVE_GETHOSTUUID=1
+**
+** None if this matters except when building on Apple products with
+** -DSQLITE_ENABLE_LOCKING_STYLE.
+*/
+#ifndef HAVE_GETHOSTUUID
+# define HAVE_GETHOSTUUID 0
+# if defined(__APPLE__) && ((__MAC_OS_X_VERSION_MIN_REQUIRED > 1050) || \
+                            (__IPHONE_OS_VERSION_MIN_REQUIRED > 2000))
+#    if (!defined(TARGET_OS_EMBEDDED) || (TARGET_OS_EMBEDDED==0)) \
+        && (!defined(TARGET_IPHONE_SIMULATOR) || (TARGET_IPHONE_SIMULATOR==0))\
+        && (!defined(TARGET_OS_MACCATALYST) || (TARGET_OS_MACCATALYST==0))
+#      undef HAVE_GETHOSTUUID
+#      define HAVE_GETHOSTUUID 1
+#    else
+#      warning "gethostuuid() is disabled."
+#    endif
+#  endif
+#endif
+
+
+#if OS_VXWORKS
+/* # include <sys/ioctl.h> */
+# include <semaphore.h>
+# include <limits.h>
+#endif /* OS_VXWORKS */
+
+#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
+# include <sys/mount.h>
+#endif
+
+#ifdef HAVE_UTIME
+# include <utime.h>
+#endif
+
+/*
+** Allowed values of unixFile.fsFlags
+*/
+#define SQLITE_FSFLAGS_IS_MSDOS     0x1
+
+/*
+** If we are to be thread-safe, include the pthreads header.
+*/
+#if SQLITE_THREADSAFE
+/* # include <pthread.h> */
+#endif
+
+/*
+** Default permissions when creating a new file
+*/
+#ifndef SQLITE_DEFAULT_FILE_PERMISSIONS
+# define SQLITE_DEFAULT_FILE_PERMISSIONS 0644
+#endif
+
+/*
+** Default permissions when creating auto proxy dir
+*/
+#ifndef SQLITE_DEFAULT_PROXYDIR_PERMISSIONS
+# define SQLITE_DEFAULT_PROXYDIR_PERMISSIONS 0755
+#endif
+
+/*
+** Maximum supported path-length.
+*/
+#define MAX_PATHNAME 512
+
+/*
+** Maximum supported symbolic links
+*/
+#define SQLITE_MAX_SYMLINKS 100
+
+/*
+** Remove and stub certain info for WASI (WebAssembly System
+** Interface) builds.
+*/
+#ifdef SQLITE_WASI
+# undef HAVE_FCHMOD
+# undef HAVE_FCHOWN
+# undef HAVE_MREMAP
+# define HAVE_MREMAP 0
+# ifndef SQLITE_DEFAULT_UNIX_VFS
+#  define SQLITE_DEFAULT_UNIX_VFS "unix-dotfile"
+   /* ^^^ should SQLITE_DEFAULT_UNIX_VFS be "unix-none"? */
+# endif
+# ifndef F_RDLCK
+#  define F_RDLCK 0
+#  define F_WRLCK 1
+#  define F_UNLCK 2
+#  if __LONG_MAX == 0x7fffffffL
+#   define F_GETLK 12
+#   define F_SETLK 13
+#   define F_SETLKW 14
+#  else
+#   define F_GETLK 5
+#   define F_SETLK 6
+#   define F_SETLKW 7
+#  endif
+# endif
+#else /* !SQLITE_WASI */
+# ifndef HAVE_FCHMOD
+#  define HAVE_FCHMOD 1
+# endif
+#endif /* SQLITE_WASI */
+
+#ifdef SQLITE_WASI
+# define osGetpid(X) (pid_t)1
+#else
+/* Always cast the getpid() return type for compatibility with
+** kernel modules in VxWorks. */
+# define osGetpid(X) (pid_t)getpid()
+#endif
+
+/*
+** Only set the lastErrno if the error code is a real error and not
+** a normal expected return code of SQLITE_BUSY or SQLITE_OK
+*/
+#define IS_LOCK_ERROR(x)  ((x != SQLITE_OK) && (x != SQLITE_BUSY))
+
+/* Forward references */
+typedef struct unixShm unixShm;               /* Connection shared memory */
+typedef struct unixShmNode unixShmNode;       /* Shared memory instance */
+typedef struct unixInodeInfo unixInodeInfo;   /* An i-node */
+typedef struct UnixUnusedFd UnixUnusedFd;     /* An unused file descriptor */
+
+/*
+** Sometimes, after a file handle is closed by SQLite, the file descriptor
+** cannot be closed immediately. In these cases, instances of the following
+** structure are used to store the file descriptor while waiting for an
+** opportunity to either close or reuse it.
+*/
+struct UnixUnusedFd {
+  int fd;                   /* File descriptor to close */
+  int flags;                /* Flags this file descriptor was opened with */
+  UnixUnusedFd *pNext;      /* Next unused file descriptor on same file */
+};
+
+/*
+** The unixFile structure is subclass of sqlite3_file specific to the unix
+** VFS implementations.
+*/
+typedef struct unixFile unixFile;
+struct unixFile {
+  sqlite3_io_methods const *pMethod;  /* Always the first entry */
+  sqlite3_vfs *pVfs;                  /* The VFS that created this unixFile */
+  unixInodeInfo *pInode;              /* Info about locks on this inode */
+  int h;                              /* The file descriptor */
+  unsigned char eFileLock;            /* The type of lock held on this fd */
+  unsigned short int ctrlFlags;       /* Behavioral bits.  UNIXFILE_* flags */
+  int lastErrno;                      /* The unix errno from last I/O error */
+  void *lockingContext;               /* Locking style specific state */
+  UnixUnusedFd *pPreallocatedUnused;  /* Pre-allocated UnixUnusedFd */
+  const char *zPath;                  /* Name of the file */
+  unixShm *pShm;                      /* Shared memory segment information */
+  int szChunk;                        /* Configured by FCNTL_CHUNK_SIZE */
+#if SQLITE_MAX_MMAP_SIZE>0
+  int nFetchOut;                      /* Number of outstanding xFetch refs */
+  sqlite3_int64 mmapSize;             /* Usable size of mapping at pMapRegion */
+  sqlite3_int64 mmapSizeActual;       /* Actual size of mapping at pMapRegion */
+  sqlite3_int64 mmapSizeMax;          /* Configured FCNTL_MMAP_SIZE value */
+  void *pMapRegion;                   /* Memory mapped region */
+#endif
+  int sectorSize;                     /* Device sector size */
+  int deviceCharacteristics;          /* Precomputed device characteristics */
+#if SQLITE_ENABLE_LOCKING_STYLE
+  int openFlags;                      /* The flags specified at open() */
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
+  unsigned fsFlags;                   /* cached details from statfs() */
+#endif
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  unsigned iBusyTimeout;              /* Wait this many millisec on locks */
+#endif
+#if OS_VXWORKS
+  struct vxworksFileId *pId;          /* Unique file ID */
+#endif
+#ifdef SQLITE_DEBUG
+  /* The next group of variables are used to track whether or not the
+  ** transaction counter in bytes 24-27 of database files are updated
+  ** whenever any part of the database changes.  An assertion fault will
+  ** occur if a file is updated without also updating the transaction
+  ** counter.  This test is made to avoid new problems similar to the
+  ** one described by ticket #3584.
+  */
+  unsigned char transCntrChng;   /* True if the transaction counter changed */
+  unsigned char dbUpdate;        /* True if any part of database file changed */
+  unsigned char inNormalWrite;   /* True if in a normal write operation */
+
+#endif
+
+#ifdef SQLITE_TEST
+  /* In test mode, increase the size of this structure a bit so that
+  ** it is larger than the struct CrashFile defined in test6.c.
+  */
+  char aPadding[32];
+#endif
+};
+
+/* This variable holds the process id (pid) from when the xRandomness()
+** method was called.  If xOpen() is called from a different process id,
+** indicating that a fork() has occurred, the PRNG will be reset.
+*/
+static pid_t randomnessPid = 0;
+
+/*
+** Allowed values for the unixFile.ctrlFlags bitmask:
+*/
+#define UNIXFILE_EXCL        0x01     /* Connections from one process only */
+#define UNIXFILE_RDONLY      0x02     /* Connection is read only */
+#define UNIXFILE_PERSIST_WAL 0x04     /* Persistent WAL mode */
+#if !defined(SQLITE_DISABLE_DIRSYNC) && !defined(_AIX)
+# define UNIXFILE_DIRSYNC    0x08     /* Directory sync needed */
+#else
+# define UNIXFILE_DIRSYNC    0x00
+#endif
+#define UNIXFILE_PSOW        0x10     /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
+#define UNIXFILE_DELETE      0x20     /* Delete on close */
+#define UNIXFILE_URI         0x40     /* Filename might have query parameters */
+#define UNIXFILE_NOLOCK      0x80     /* Do no file locking */
+
+/*
+** Include code that is common to all os_*.c files
+*/
+/* #include "os_common.h" */
+
+/*
+** Define various macros that are missing from some systems.
+*/
+#ifndef O_LARGEFILE
+# define O_LARGEFILE 0
+#endif
+#ifdef SQLITE_DISABLE_LFS
+# undef O_LARGEFILE
+# define O_LARGEFILE 0
+#endif
+#ifndef O_NOFOLLOW
+# define O_NOFOLLOW 0
+#endif
+#ifndef O_BINARY
+# define O_BINARY 0
+#endif
+
+/*
+** The threadid macro resolves to the thread-id or to 0.  Used for
+** testing and debugging only.
+*/
+#if SQLITE_THREADSAFE
+#define threadid pthread_self()
+#else
+#define threadid 0
+#endif
+
+/*
+** HAVE_MREMAP defaults to true on Linux and false everywhere else.
+*/
+#if !defined(HAVE_MREMAP)
+# if defined(__linux__) && defined(_GNU_SOURCE)
+#  define HAVE_MREMAP 1
+# else
+#  define HAVE_MREMAP 0
+# endif
+#endif
+
+/*
+** Explicitly call the 64-bit version of lseek() on Android. Otherwise, lseek()
+** is the 32-bit version, even if _FILE_OFFSET_BITS=64 is defined.
+*/
+#ifdef __ANDROID__
+# define lseek lseek64
+#endif
+
+#ifdef __linux__
+/*
+** Linux-specific IOCTL magic numbers used for controlling F2FS
+*/
+#define F2FS_IOCTL_MAGIC        0xf5
+#define F2FS_IOC_START_ATOMIC_WRITE     _IO(F2FS_IOCTL_MAGIC, 1)
+#define F2FS_IOC_COMMIT_ATOMIC_WRITE    _IO(F2FS_IOCTL_MAGIC, 2)
+#define F2FS_IOC_START_VOLATILE_WRITE   _IO(F2FS_IOCTL_MAGIC, 3)
+#define F2FS_IOC_ABORT_VOLATILE_WRITE   _IO(F2FS_IOCTL_MAGIC, 5)
+#define F2FS_IOC_GET_FEATURES           _IOR(F2FS_IOCTL_MAGIC, 12, u32)
+#define F2FS_FEATURE_ATOMIC_WRITE 0x0004
+#endif /* __linux__ */
+
+
+/*
+** Different Unix systems declare open() in different ways.  Same use
+** open(const char*,int,mode_t).  Others use open(const char*,int,...).
+** The difference is important when using a pointer to the function.
+**
+** The safest way to deal with the problem is to always use this wrapper
+** which always has the same well-defined interface.
+*/
+static int posixOpen(const char *zFile, int flags, int mode){
+  return open(zFile, flags, mode);
+}
+
+/* Forward reference */
+static int openDirectory(const char*, int*);
+static int unixGetpagesize(void);
+
+/*
+** Many system calls are accessed through pointer-to-functions so that
+** they may be overridden at runtime to facilitate fault injection during
+** testing and sandboxing.  The following array holds the names and pointers
+** to all overrideable system calls.
+*/
+static struct unix_syscall {
+  const char *zName;            /* Name of the system call */
+  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
+  sqlite3_syscall_ptr pDefault; /* Default value */
+} aSyscall[] = {
+  { "open",         (sqlite3_syscall_ptr)posixOpen,  0  },
+#define osOpen      ((int(*)(const char*,int,int))aSyscall[0].pCurrent)
+
+  { "close",        (sqlite3_syscall_ptr)close,      0  },
+#define osClose     ((int(*)(int))aSyscall[1].pCurrent)
+
+  { "access",       (sqlite3_syscall_ptr)access,     0  },
+#define osAccess    ((int(*)(const char*,int))aSyscall[2].pCurrent)
+
+  { "getcwd",       (sqlite3_syscall_ptr)getcwd,     0  },
+#define osGetcwd    ((char*(*)(char*,size_t))aSyscall[3].pCurrent)
+
+  { "stat",         (sqlite3_syscall_ptr)stat,       0  },
+#define osStat      ((int(*)(const char*,struct stat*))aSyscall[4].pCurrent)
+
+/*
+** The DJGPP compiler environment looks mostly like Unix, but it
+** lacks the fcntl() system call.  So redefine fcntl() to be something
+** that always succeeds.  This means that locking does not occur under
+** DJGPP.  But it is DOS - what did you expect?
+*/
+#ifdef __DJGPP__
+  { "fstat",        0,                 0  },
+#define osFstat(a,b,c)    0
+#else
+  { "fstat",        (sqlite3_syscall_ptr)fstat,      0  },
+#define osFstat     ((int(*)(int,struct stat*))aSyscall[5].pCurrent)
+#endif
+
+  { "ftruncate",    (sqlite3_syscall_ptr)ftruncate,  0  },
+#define osFtruncate ((int(*)(int,off_t))aSyscall[6].pCurrent)
+
+  { "fcntl",        (sqlite3_syscall_ptr)fcntl,      0  },
+#define osFcntl     ((int(*)(int,int,...))aSyscall[7].pCurrent)
+
+  { "read",         (sqlite3_syscall_ptr)read,       0  },
+#define osRead      ((ssize_t(*)(int,void*,size_t))aSyscall[8].pCurrent)
+
+#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE
+  { "pread",        (sqlite3_syscall_ptr)pread,      0  },
+#else
+  { "pread",        (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPread     ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[9].pCurrent)
+
+#if defined(USE_PREAD64)
+  { "pread64",      (sqlite3_syscall_ptr)pread64,    0  },
+#else
+  { "pread64",      (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPread64 ((ssize_t(*)(int,void*,size_t,off64_t))aSyscall[10].pCurrent)
+
+  { "write",        (sqlite3_syscall_ptr)write,      0  },
+#define osWrite     ((ssize_t(*)(int,const void*,size_t))aSyscall[11].pCurrent)
+
+#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE
+  { "pwrite",       (sqlite3_syscall_ptr)pwrite,     0  },
+#else
+  { "pwrite",       (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPwrite    ((ssize_t(*)(int,const void*,size_t,off_t))\
+                    aSyscall[12].pCurrent)
+
+#if defined(USE_PREAD64)
+  { "pwrite64",     (sqlite3_syscall_ptr)pwrite64,   0  },
+#else
+  { "pwrite64",     (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPwrite64  ((ssize_t(*)(int,const void*,size_t,off64_t))\
+                    aSyscall[13].pCurrent)
+
+#if defined(HAVE_FCHMOD)
+  { "fchmod",       (sqlite3_syscall_ptr)fchmod,          0  },
+#else
+  { "fchmod",       (sqlite3_syscall_ptr)0,               0  },
+#endif
+#define osFchmod    ((int(*)(int,mode_t))aSyscall[14].pCurrent)
+
+#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE
+  { "fallocate",    (sqlite3_syscall_ptr)posix_fallocate,  0 },
+#else
+  { "fallocate",    (sqlite3_syscall_ptr)0,                0 },
+#endif
+#define osFallocate ((int(*)(int,off_t,off_t))aSyscall[15].pCurrent)
+
+  { "unlink",       (sqlite3_syscall_ptr)unlink,           0 },
+#define osUnlink    ((int(*)(const char*))aSyscall[16].pCurrent)
+
+  { "openDirectory",    (sqlite3_syscall_ptr)openDirectory,      0 },
+#define osOpenDirectory ((int(*)(const char*,int*))aSyscall[17].pCurrent)
+
+  { "mkdir",        (sqlite3_syscall_ptr)mkdir,           0 },
+#define osMkdir     ((int(*)(const char*,mode_t))aSyscall[18].pCurrent)
+
+  { "rmdir",        (sqlite3_syscall_ptr)rmdir,           0 },
+#define osRmdir     ((int(*)(const char*))aSyscall[19].pCurrent)
+
+#if defined(HAVE_FCHOWN)
+  { "fchown",       (sqlite3_syscall_ptr)fchown,          0 },
+#else
+  { "fchown",       (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osFchown    ((int(*)(int,uid_t,gid_t))aSyscall[20].pCurrent)
+
+#if defined(HAVE_FCHOWN)
+  { "geteuid",      (sqlite3_syscall_ptr)geteuid,         0 },
+#else
+  { "geteuid",      (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osGeteuid   ((uid_t(*)(void))aSyscall[21].pCurrent)
+
+#if (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0) \
+  && !defined(SQLITE_WASI)
+  { "mmap",         (sqlite3_syscall_ptr)mmap,            0 },
+#else
+  { "mmap",         (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osMmap ((void*(*)(void*,size_t,int,int,int,off_t))aSyscall[22].pCurrent)
+
+#if (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0) \
+  && !defined(SQLITE_WASI)
+  { "munmap",       (sqlite3_syscall_ptr)munmap,          0 },
+#else
+  { "munmap",       (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osMunmap ((int(*)(void*,size_t))aSyscall[23].pCurrent)
+
+#if HAVE_MREMAP && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
+  { "mremap",       (sqlite3_syscall_ptr)mremap,          0 },
+#else
+  { "mremap",       (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osMremap ((void*(*)(void*,size_t,size_t,int,...))aSyscall[24].pCurrent)
+
+#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
+  { "getpagesize",  (sqlite3_syscall_ptr)unixGetpagesize, 0 },
+#else
+  { "getpagesize",  (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osGetpagesize ((int(*)(void))aSyscall[25].pCurrent)
+
+#if defined(HAVE_READLINK)
+  { "readlink",     (sqlite3_syscall_ptr)readlink,        0 },
+#else
+  { "readlink",     (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osReadlink ((ssize_t(*)(const char*,char*,size_t))aSyscall[26].pCurrent)
+
+#if defined(HAVE_LSTAT)
+  { "lstat",         (sqlite3_syscall_ptr)lstat,          0 },
+#else
+  { "lstat",         (sqlite3_syscall_ptr)0,              0 },
+#endif
+#define osLstat      ((int(*)(const char*,struct stat*))aSyscall[27].pCurrent)
+
+#if defined(__linux__) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+# ifdef __ANDROID__
+  { "ioctl", (sqlite3_syscall_ptr)(int(*)(int, int, ...))ioctl, 0 },
+#define osIoctl ((int(*)(int,int,...))aSyscall[28].pCurrent)
+# else
+  { "ioctl",         (sqlite3_syscall_ptr)ioctl,          0 },
+#define osIoctl ((int(*)(int,unsigned long,...))aSyscall[28].pCurrent)
+# endif
+#else
+  { "ioctl",         (sqlite3_syscall_ptr)0,              0 },
+#endif
+
+}; /* End of the overrideable system calls */
+
+
+/*
+** On some systems, calls to fchown() will trigger a message in a security
+** log if they come from non-root processes.  So avoid calling fchown() if
+** we are not running as root.
+*/
+static int robustFchown(int fd, uid_t uid, gid_t gid){
+#if defined(HAVE_FCHOWN)
+  return osGeteuid() ? 0 : osFchown(fd,uid,gid);
+#else
+  return 0;
+#endif
+}
+
+/*
+** This is the xSetSystemCall() method of sqlite3_vfs for all of the
+** "unix" VFSes.  Return SQLITE_OK upon successfully updating the
+** system call pointer, or SQLITE_NOTFOUND if there is no configurable
+** system call named zName.
+*/
+static int unixSetSystemCall(
+  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
+  const char *zName,            /* Name of system call to override */
+  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */
+){
+  unsigned int i;
+  int rc = SQLITE_NOTFOUND;
+
+  UNUSED_PARAMETER(pNotUsed);
+  if( zName==0 ){
+    /* If no zName is given, restore all system calls to their default
+    ** settings and return NULL
+    */
+    rc = SQLITE_OK;
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( aSyscall[i].pDefault ){
+        aSyscall[i].pCurrent = aSyscall[i].pDefault;
+      }
+    }
+  }else{
+    /* If zName is specified, operate on only the one system call
+    ** specified.
+    */
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ){
+        if( aSyscall[i].pDefault==0 ){
+          aSyscall[i].pDefault = aSyscall[i].pCurrent;
+        }
+        rc = SQLITE_OK;
+        if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault;
+        aSyscall[i].pCurrent = pNewFunc;
+        break;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the value of a system call.  Return NULL if zName is not a
+** recognized system call name.  NULL is also returned if the system call
+** is currently undefined.
+*/
+static sqlite3_syscall_ptr unixGetSystemCall(
+  sqlite3_vfs *pNotUsed,
+  const char *zName
+){
+  unsigned int i;
+
+  UNUSED_PARAMETER(pNotUsed);
+  for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+    if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent;
+  }
+  return 0;
+}
+
+/*
+** Return the name of the first system call after zName.  If zName==NULL
+** then return the name of the first system call.  Return NULL if zName
+** is the last system call or if zName is not the name of a valid
+** system call.
+*/
+static const char *unixNextSystemCall(sqlite3_vfs *p, const char *zName){
+  int i = -1;
+
+  UNUSED_PARAMETER(p);
+  if( zName ){
+    for(i=0; i<ArraySize(aSyscall)-1; i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ) break;
+    }
+  }
+  for(i++; i<ArraySize(aSyscall); i++){
+    if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName;
+  }
+  return 0;
+}
+
+/*
+** Do not accept any file descriptor less than this value, in order to avoid
+** opening database file using file descriptors that are commonly used for
+** standard input, output, and error.
+*/
+#ifndef SQLITE_MINIMUM_FILE_DESCRIPTOR
+# define SQLITE_MINIMUM_FILE_DESCRIPTOR 3
+#endif
+
+/*
+** Invoke open().  Do so multiple times, until it either succeeds or
+** fails for some reason other than EINTR.
+**
+** If the file creation mode "m" is 0 then set it to the default for
+** SQLite.  The default is SQLITE_DEFAULT_FILE_PERMISSIONS (normally
+** 0644) as modified by the system umask.  If m is not 0, then
+** make the file creation mode be exactly m ignoring the umask.
+**
+** The m parameter will be non-zero only when creating -wal, -journal,
+** and -shm files.  We want those files to have *exactly* the same
+** permissions as their original database, unadulterated by the umask.
+** In that way, if a database file is -rw-rw-rw or -rw-rw-r-, and a
+** transaction crashes and leaves behind hot journals, then any
+** process that is able to write to the database will also be able to
+** recover the hot journals.
+*/
+static int robust_open(const char *z, int f, mode_t m){
+  int fd;
+  mode_t m2 = m ? m : SQLITE_DEFAULT_FILE_PERMISSIONS;
+  while(1){
+#if defined(O_CLOEXEC)
+    fd = osOpen(z,f|O_CLOEXEC,m2);
+#else
+    fd = osOpen(z,f,m2);
+#endif
+    if( fd<0 ){
+      if( errno==EINTR ) continue;
+      break;
+    }
+    if( fd>=SQLITE_MINIMUM_FILE_DESCRIPTOR ) break;
+    if( (f & (O_EXCL|O_CREAT))==(O_EXCL|O_CREAT) ){
+      (void)osUnlink(z);
+    }
+    osClose(fd);
+    sqlite3_log(SQLITE_WARNING,
+                "attempt to open \"%s\" as file descriptor %d", z, fd);
+    fd = -1;
+    if( osOpen("/dev/null", O_RDONLY, m)<0 ) break;
+  }
+  if( fd>=0 ){
+    if( m!=0 ){
+      struct stat statbuf;
+      if( osFstat(fd, &statbuf)==0
+       && statbuf.st_size==0
+       && (statbuf.st_mode&0777)!=m
+      ){
+        osFchmod(fd, m);
+      }
+    }
+#if defined(FD_CLOEXEC) && (!defined(O_CLOEXEC) || O_CLOEXEC==0)
+    osFcntl(fd, F_SETFD, osFcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
+#endif
+  }
+  return fd;
+}
+
+/*
+** Helper functions to obtain and relinquish the global mutex. The
+** global mutex is used to protect the unixInodeInfo and
+** vxworksFileId objects used by this file, all of which may be
+** shared by multiple threads.
+**
+** Function unixMutexHeld() is used to assert() that the global mutex
+** is held when required. This function is only used as part of assert()
+** statements. e.g.
+**
+**   unixEnterMutex()
+**     assert( unixMutexHeld() );
+**   unixEnterLeave()
+**
+** To prevent deadlock, the global unixBigLock must must be acquired
+** before the unixInodeInfo.pLockMutex mutex, if both are held.  It is
+** OK to get the pLockMutex without holding unixBigLock first, but if
+** that happens, the unixBigLock mutex must not be acquired until after
+** pLockMutex is released.
+**
+**      OK:     enter(unixBigLock),  enter(pLockInfo)
+**      OK:     enter(unixBigLock)
+**      OK:     enter(pLockInfo)
+**   ERROR:     enter(pLockInfo), enter(unixBigLock)
+*/
+static sqlite3_mutex *unixBigLock = 0;
+static void unixEnterMutex(void){
+  assert( sqlite3_mutex_notheld(unixBigLock) );  /* Not a recursive mutex */
+  sqlite3_mutex_enter(unixBigLock);
+}
+static void unixLeaveMutex(void){
+  assert( sqlite3_mutex_held(unixBigLock) );
+  sqlite3_mutex_leave(unixBigLock);
+}
+#ifdef SQLITE_DEBUG
+static int unixMutexHeld(void) {
+  return sqlite3_mutex_held(unixBigLock);
+}
+#endif
+
+
+#ifdef SQLITE_HAVE_OS_TRACE
+/*
+** Helper function for printing out trace information from debugging
+** binaries. This returns the string representation of the supplied
+** integer lock-type.
+*/
+static const char *azFileLock(int eFileLock){
+  switch( eFileLock ){
+    case NO_LOCK: return "NONE";
+    case SHARED_LOCK: return "SHARED";
+    case RESERVED_LOCK: return "RESERVED";
+    case PENDING_LOCK: return "PENDING";
+    case EXCLUSIVE_LOCK: return "EXCLUSIVE";
+  }
+  return "ERROR";
+}
+#endif
+
+#ifdef SQLITE_LOCK_TRACE
+/*
+** Print out information about all locking operations.
+**
+** This routine is used for troubleshooting locks on multithreaded
+** platforms.  Enable by compiling with the -DSQLITE_LOCK_TRACE
+** command-line option on the compiler.  This code is normally
+** turned off.
+*/
+static int lockTrace(int fd, int op, struct flock *p){
+  char *zOpName, *zType;
+  int s;
+  int savedErrno;
+  if( op==F_GETLK ){
+    zOpName = "GETLK";
+  }else if( op==F_SETLK ){
+    zOpName = "SETLK";
+  }else{
+    s = osFcntl(fd, op, p);
+    sqlite3DebugPrintf("fcntl unknown %d %d %d\n", fd, op, s);
+    return s;
+  }
+  if( p->l_type==F_RDLCK ){
+    zType = "RDLCK";
+  }else if( p->l_type==F_WRLCK ){
+    zType = "WRLCK";
+  }else if( p->l_type==F_UNLCK ){
+    zType = "UNLCK";
+  }else{
+    assert( 0 );
+  }
+  assert( p->l_whence==SEEK_SET );
+  s = osFcntl(fd, op, p);
+  savedErrno = errno;
+  sqlite3DebugPrintf("fcntl %d %d %s %s %d %d %d %d\n",
+     threadid, fd, zOpName, zType, (int)p->l_start, (int)p->l_len,
+     (int)p->l_pid, s);
+  if( s==(-1) && op==F_SETLK && (p->l_type==F_RDLCK || p->l_type==F_WRLCK) ){
+    struct flock l2;
+    l2 = *p;
+    osFcntl(fd, F_GETLK, &l2);
+    if( l2.l_type==F_RDLCK ){
+      zType = "RDLCK";
+    }else if( l2.l_type==F_WRLCK ){
+      zType = "WRLCK";
+    }else if( l2.l_type==F_UNLCK ){
+      zType = "UNLCK";
+    }else{
+      assert( 0 );
+    }
+    sqlite3DebugPrintf("fcntl-failure-reason: %s %d %d %d\n",
+       zType, (int)l2.l_start, (int)l2.l_len, (int)l2.l_pid);
+  }
+  errno = savedErrno;
+  return s;
+}
+#undef osFcntl
+#define osFcntl lockTrace
+#endif /* SQLITE_LOCK_TRACE */
+
+/*
+** Retry ftruncate() calls that fail due to EINTR
+**
+** All calls to ftruncate() within this file should be made through
+** this wrapper.  On the Android platform, bypassing the logic below
+** could lead to a corrupt database.
+*/
+static int robust_ftruncate(int h, sqlite3_int64 sz){
+  int rc;
+#ifdef __ANDROID__
+  /* On Android, ftruncate() always uses 32-bit offsets, even if
+  ** _FILE_OFFSET_BITS=64 is defined. This means it is unsafe to attempt to
+  ** truncate a file to any size larger than 2GiB. Silently ignore any
+  ** such attempts.  */
+  if( sz>(sqlite3_int64)0x7FFFFFFF ){
+    rc = SQLITE_OK;
+  }else
+#endif
+  do{ rc = osFtruncate(h,sz); }while( rc<0 && errno==EINTR );
+  return rc;
+}
+
+/*
+** This routine translates a standard POSIX errno code into something
+** useful to the clients of the sqlite3 functions.  Specifically, it is
+** intended to translate a variety of "try again" errors into SQLITE_BUSY
+** and a variety of "please close the file descriptor NOW" errors into
+** SQLITE_IOERR
+**
+** Errors during initialization of locks, or file system support for locks,
+** should handle ENOLCK, ENOTSUP, EOPNOTSUPP separately.
+*/
+static int sqliteErrorFromPosixError(int posixError, int sqliteIOErr) {
+  assert( (sqliteIOErr == SQLITE_IOERR_LOCK) ||
+          (sqliteIOErr == SQLITE_IOERR_UNLOCK) ||
+          (sqliteIOErr == SQLITE_IOERR_RDLOCK) ||
+          (sqliteIOErr == SQLITE_IOERR_CHECKRESERVEDLOCK) );
+  switch (posixError) {
+  case EACCES:
+  case EAGAIN:
+  case ETIMEDOUT:
+  case EBUSY:
+  case EINTR:
+  case ENOLCK:
+    /* random NFS retry error, unless during file system support
+     * introspection, in which it actually means what it says */
+    return SQLITE_BUSY;
+
+  case EPERM:
+    return SQLITE_PERM;
+
+  default:
+    return sqliteIOErr;
+  }
+}
+
+
+/******************************************************************************
+****************** Begin Unique File ID Utility Used By VxWorks ***************
+**
+** On most versions of unix, we can get a unique ID for a file by concatenating
+** the device number and the inode number.  But this does not work on VxWorks.
+** On VxWorks, a unique file id must be based on the canonical filename.
+**
+** A pointer to an instance of the following structure can be used as a
+** unique file ID in VxWorks.  Each instance of this structure contains
+** a copy of the canonical filename.  There is also a reference count.
+** The structure is reclaimed when the number of pointers to it drops to
+** zero.
+**
+** There are never very many files open at one time and lookups are not
+** a performance-critical path, so it is sufficient to put these
+** structures on a linked list.
+*/
+struct vxworksFileId {
+  struct vxworksFileId *pNext;  /* Next in a list of them all */
+  int nRef;                     /* Number of references to this one */
+  int nName;                    /* Length of the zCanonicalName[] string */
+  char *zCanonicalName;         /* Canonical filename */
+};
+
+#if OS_VXWORKS
+/*
+** All unique filenames are held on a linked list headed by this
+** variable:
+*/
+static struct vxworksFileId *vxworksFileList = 0;
+
+/*
+** Simplify a filename into its canonical form
+** by making the following changes:
+**
+**  * removing any trailing and duplicate /
+**  * convert /./ into just /
+**  * convert /A/../ where A is any simple name into just /
+**
+** Changes are made in-place.  Return the new name length.
+**
+** The original filename is in z[0..n-1].  Return the number of
+** characters in the simplified name.
+*/
+static int vxworksSimplifyName(char *z, int n){
+  int i, j;
+  while( n>1 && z[n-1]=='/' ){ n--; }
+  for(i=j=0; i<n; i++){
+    if( z[i]=='/' ){
+      if( z[i+1]=='/' ) continue;
+      if( z[i+1]=='.' && i+2<n && z[i+2]=='/' ){
+        i += 1;
+        continue;
+      }
+      if( z[i+1]=='.' && i+3<n && z[i+2]=='.' && z[i+3]=='/' ){
+        while( j>0 && z[j-1]!='/' ){ j--; }
+        if( j>0 ){ j--; }
+        i += 2;
+        continue;
+      }
+    }
+    z[j++] = z[i];
+  }
+  z[j] = 0;
+  return j;
+}
+
+/*
+** Find a unique file ID for the given absolute pathname.  Return
+** a pointer to the vxworksFileId object.  This pointer is the unique
+** file ID.
+**
+** The nRef field of the vxworksFileId object is incremented before
+** the object is returned.  A new vxworksFileId object is created
+** and added to the global list if necessary.
+**
+** If a memory allocation error occurs, return NULL.
+*/
+static struct vxworksFileId *vxworksFindFileId(const char *zAbsoluteName){
+  struct vxworksFileId *pNew;         /* search key and new file ID */
+  struct vxworksFileId *pCandidate;   /* For looping over existing file IDs */
+  int n;                              /* Length of zAbsoluteName string */
+
+  assert( zAbsoluteName[0]=='/' );
+  n = (int)strlen(zAbsoluteName);
+  pNew = sqlite3_malloc64( sizeof(*pNew) + (n+1) );
+  if( pNew==0 ) return 0;
+  pNew->zCanonicalName = (char*)&pNew[1];
+  memcpy(pNew->zCanonicalName, zAbsoluteName, n+1);
+  n = vxworksSimplifyName(pNew->zCanonicalName, n);
+
+  /* Search for an existing entry that matching the canonical name.
+  ** If found, increment the reference count and return a pointer to
+  ** the existing file ID.
+  */
+  unixEnterMutex();
+  for(pCandidate=vxworksFileList; pCandidate; pCandidate=pCandidate->pNext){
+    if( pCandidate->nName==n
+     && memcmp(pCandidate->zCanonicalName, pNew->zCanonicalName, n)==0
+    ){
+       sqlite3_free(pNew);
+       pCandidate->nRef++;
+       unixLeaveMutex();
+       return pCandidate;
+    }
+  }
+
+  /* No match was found.  We will make a new file ID */
+  pNew->nRef = 1;
+  pNew->nName = n;
+  pNew->pNext = vxworksFileList;
+  vxworksFileList = pNew;
+  unixLeaveMutex();
+  return pNew;
+}
+
+/*
+** Decrement the reference count on a vxworksFileId object.  Free
+** the object when the reference count reaches zero.
+*/
+static void vxworksReleaseFileId(struct vxworksFileId *pId){
+  unixEnterMutex();
+  assert( pId->nRef>0 );
+  pId->nRef--;
+  if( pId->nRef==0 ){
+    struct vxworksFileId **pp;
+    for(pp=&vxworksFileList; *pp && *pp!=pId; pp = &((*pp)->pNext)){}
+    assert( *pp==pId );
+    *pp = pId->pNext;
+    sqlite3_free(pId);
+  }
+  unixLeaveMutex();
+}
+#endif /* OS_VXWORKS */
+/*************** End of Unique File ID Utility Used By VxWorks ****************
+******************************************************************************/
+
+
+/******************************************************************************
+*************************** Posix Advisory Locking ****************************
+**
+** POSIX advisory locks are broken by design.  ANSI STD 1003.1 (1996)
+** section 6.5.2.2 lines 483 through 490 specify that when a process
+** sets or clears a lock, that operation overrides any prior locks set
+** by the same process.  It does not explicitly say so, but this implies
+** that it overrides locks set by the same process using a different
+** file descriptor.  Consider this test case:
+**
+**       int fd1 = open("./file1", O_RDWR|O_CREAT, 0644);
+**       int fd2 = open("./file2", O_RDWR|O_CREAT, 0644);
+**
+** Suppose ./file1 and ./file2 are really the same file (because
+** one is a hard or symbolic link to the other) then if you set
+** an exclusive lock on fd1, then try to get an exclusive lock
+** on fd2, it works.  I would have expected the second lock to
+** fail since there was already a lock on the file due to fd1.
+** But not so.  Since both locks came from the same process, the
+** second overrides the first, even though they were on different
+** file descriptors opened on different file names.
+**
+** This means that we cannot use POSIX locks to synchronize file access
+** among competing threads of the same process.  POSIX locks will work fine
+** to synchronize access for threads in separate processes, but not
+** threads within the same process.
+**
+** To work around the problem, SQLite has to manage file locks internally
+** on its own.  Whenever a new database is opened, we have to find the
+** specific inode of the database file (the inode is determined by the
+** st_dev and st_ino fields of the stat structure that fstat() fills in)
+** and check for locks already existing on that inode.  When locks are
+** created or removed, we have to look at our own internal record of the
+** locks to see if another thread has previously set a lock on that same
+** inode.
+**
+** (Aside: The use of inode numbers as unique IDs does not work on VxWorks.
+** For VxWorks, we have to use the alternative unique ID system based on
+** canonical filename and implemented in the previous division.)
+**
+** The sqlite3_file structure for POSIX is no longer just an integer file
+** descriptor.  It is now a structure that holds the integer file
+** descriptor and a pointer to a structure that describes the internal
+** locks on the corresponding inode.  There is one locking structure
+** per inode, so if the same inode is opened twice, both unixFile structures
+** point to the same locking structure.  The locking structure keeps
+** a reference count (so we will know when to delete it) and a "cnt"
+** field that tells us its internal lock status.  cnt==0 means the
+** file is unlocked.  cnt==-1 means the file has an exclusive lock.
+** cnt>0 means there are cnt shared locks on the file.
+**
+** Any attempt to lock or unlock a file first checks the locking
+** structure.  The fcntl() system call is only invoked to set a
+** POSIX lock if the internal lock structure transitions between
+** a locked and an unlocked state.
+**
+** But wait:  there are yet more problems with POSIX advisory locks.
+**
+** If you close a file descriptor that points to a file that has locks,
+** all locks on that file that are owned by the current process are
+** released.  To work around this problem, each unixInodeInfo object
+** maintains a count of the number of pending locks on the inode.
+** When an attempt is made to close an unixFile, if there are
+** other unixFile open on the same inode that are holding locks, the call
+** to close() the file descriptor is deferred until all of the locks clear.
+** The unixInodeInfo structure keeps a list of file descriptors that need to
+** be closed and that list is walked (and cleared) when the last lock
+** clears.
+**
+** Yet another problem:  LinuxThreads do not play well with posix locks.
+**
+** Many older versions of linux use the LinuxThreads library which is
+** not posix compliant.  Under LinuxThreads, a lock created by thread
+** A cannot be modified or overridden by a different thread B.
+** Only thread A can modify the lock.  Locking behavior is correct
+** if the application uses the newer Native Posix Thread Library (NPTL)
+** on linux - with NPTL a lock created by thread A can override locks
+** in thread B.  But there is no way to know at compile-time which
+** threading library is being used.  So there is no way to know at
+** compile-time whether or not thread A can override locks on thread B.
+** One has to do a run-time check to discover the behavior of the
+** current process.
+**
+** SQLite used to support LinuxThreads.  But support for LinuxThreads
+** was dropped beginning with version 3.7.0.  SQLite will still work with
+** LinuxThreads provided that (1) there is no more than one connection
+** per database file in the same process and (2) database connections
+** do not move across threads.
+*/
+
+/*
+** An instance of the following structure serves as the key used
+** to locate a particular unixInodeInfo object.
+*/
+struct unixFileId {
+  dev_t dev;                  /* Device number */
+#if OS_VXWORKS
+  struct vxworksFileId *pId;  /* Unique file ID for vxworks. */
+#else
+  /* We are told that some versions of Android contain a bug that
+  ** sizes ino_t at only 32-bits instead of 64-bits. (See
+  ** https://android-review.googlesource.com/#/c/115351/3/dist/sqlite3.c)
+  ** To work around this, always allocate 64-bits for the inode number.
+  ** On small machines that only have 32-bit inodes, this wastes 4 bytes,
+  ** but that should not be a big deal. */
+  /* WAS:  ino_t ino;   */
+  u64 ino;                   /* Inode number */
+#endif
+};
+
+/*
+** An instance of the following structure is allocated for each open
+** inode.
+**
+** A single inode can have multiple file descriptors, so each unixFile
+** structure contains a pointer to an instance of this object and this
+** object keeps a count of the number of unixFile pointing to it.
+**
+** Mutex rules:
+**
+**  (1) Only the pLockMutex mutex must be held in order to read or write
+**      any of the locking fields:
+**          nShared, nLock, eFileLock, bProcessLock, pUnused
+**
+**  (2) When nRef>0, then the following fields are unchanging and can
+**      be read (but not written) without holding any mutex:
+**          fileId, pLockMutex
+**
+**  (3) With the exceptions above, all the fields may only be read
+**      or written while holding the global unixBigLock mutex.
+**
+** Deadlock prevention:  The global unixBigLock mutex may not
+** be acquired while holding the pLockMutex mutex.  If both unixBigLock
+** and pLockMutex are needed, then unixBigLock must be acquired first.
+*/
+struct unixInodeInfo {
+  struct unixFileId fileId;       /* The lookup key */
+  sqlite3_mutex *pLockMutex;      /* Hold this mutex for... */
+  int nShared;                      /* Number of SHARED locks held */
+  int nLock;                        /* Number of outstanding file locks */
+  unsigned char eFileLock;          /* One of SHARED_LOCK, RESERVED_LOCK etc. */
+  unsigned char bProcessLock;       /* An exclusive process lock is held */
+  UnixUnusedFd *pUnused;            /* Unused file descriptors to close */
+  int nRef;                       /* Number of pointers to this structure */
+  unixShmNode *pShmNode;          /* Shared memory associated with this inode */
+  unixInodeInfo *pNext;           /* List of all unixInodeInfo objects */
+  unixInodeInfo *pPrev;           /*    .... doubly linked */
+#if SQLITE_ENABLE_LOCKING_STYLE
+  unsigned long long sharedByte;  /* for AFP simulated shared lock */
+#endif
+#if OS_VXWORKS
+  sem_t *pSem;                    /* Named POSIX semaphore */
+  char aSemName[MAX_PATHNAME+2];  /* Name of that semaphore */
+#endif
+};
+
+/*
+** A lists of all unixInodeInfo objects.
+**
+** Must hold unixBigLock in order to read or write this variable.
+*/
+static unixInodeInfo *inodeList = 0;  /* All unixInodeInfo objects */
+
+#ifdef SQLITE_DEBUG
+/*
+** True if the inode mutex (on the unixFile.pFileMutex field) is held, or not.
+** This routine is used only within assert() to help verify correct mutex
+** usage.
+*/
+int unixFileMutexHeld(unixFile *pFile){
+  assert( pFile->pInode );
+  return sqlite3_mutex_held(pFile->pInode->pLockMutex);
+}
+int unixFileMutexNotheld(unixFile *pFile){
+  assert( pFile->pInode );
+  return sqlite3_mutex_notheld(pFile->pInode->pLockMutex);
+}
+#endif
+
+/*
+**
+** This function - unixLogErrorAtLine(), is only ever called via the macro
+** unixLogError().
+**
+** It is invoked after an error occurs in an OS function and errno has been
+** set. It logs a message using sqlite3_log() containing the current value of
+** errno and, if possible, the human-readable equivalent from strerror() or
+** strerror_r().
+**
+** The first argument passed to the macro should be the error code that
+** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN).
+** The two subsequent arguments should be the name of the OS function that
+** failed (e.g. "unlink", "open") and the associated file-system path,
+** if any.
+*/
+#define unixLogError(a,b,c)     unixLogErrorAtLine(a,b,c,__LINE__)
+static int unixLogErrorAtLine(
+  int errcode,                    /* SQLite error code */
+  const char *zFunc,              /* Name of OS function that failed */
+  const char *zPath,              /* File path associated with error */
+  int iLine                       /* Source line number where error occurred */
+){
+  char *zErr;                     /* Message from strerror() or equivalent */
+  int iErrno = errno;             /* Saved syscall error number */
+
+  /* If this is not a threadsafe build (SQLITE_THREADSAFE==0), then use
+  ** the strerror() function to obtain the human-readable error message
+  ** equivalent to errno. Otherwise, use strerror_r().
+  */
+#if SQLITE_THREADSAFE && defined(HAVE_STRERROR_R)
+  char aErr[80];
+  memset(aErr, 0, sizeof(aErr));
+  zErr = aErr;
+
+  /* If STRERROR_R_CHAR_P (set by autoconf scripts) or __USE_GNU is defined,
+  ** assume that the system provides the GNU version of strerror_r() that
+  ** returns a pointer to a buffer containing the error message. That pointer
+  ** may point to aErr[], or it may point to some static storage somewhere.
+  ** Otherwise, assume that the system provides the POSIX version of
+  ** strerror_r(), which always writes an error message into aErr[].
+  **
+  ** If the code incorrectly assumes that it is the POSIX version that is
+  ** available, the error message will often be an empty string. Not a
+  ** huge problem. Incorrectly concluding that the GNU version is available
+  ** could lead to a segfault though.
+  **
+  ** Forum post 3f13857fa4062301 reports that the Android SDK may use
+  ** int-type return, depending on its version.
+  */
+#if (defined(STRERROR_R_CHAR_P) || defined(__USE_GNU)) \
+  && !defined(ANDROID) && !defined(__ANDROID__)
+  zErr =
+# endif
+  strerror_r(iErrno, aErr, sizeof(aErr)-1);
+
+#elif SQLITE_THREADSAFE
+  /* This is a threadsafe build, but strerror_r() is not available. */
+  zErr = "";
+#else
+  /* Non-threadsafe build, use strerror(). */
+  zErr = strerror(iErrno);
+#endif
+
+  if( zPath==0 ) zPath = "";
+  sqlite3_log(errcode,
+      "os_unix.c:%d: (%d) %s(%s) - %s",
+      iLine, iErrno, zFunc, zPath, zErr
+  );
+
+  return errcode;
+}
+
+/*
+** Close a file descriptor.
+**
+** We assume that close() almost always works, since it is only in a
+** very sick application or on a very sick platform that it might fail.
+** If it does fail, simply leak the file descriptor, but do log the
+** error.
+**
+** Note that it is not safe to retry close() after EINTR since the
+** file descriptor might have already been reused by another thread.
+** So we don't even try to recover from an EINTR.  Just log the error
+** and move on.
+*/
+static void robust_close(unixFile *pFile, int h, int lineno){
+  if( osClose(h) ){
+    unixLogErrorAtLine(SQLITE_IOERR_CLOSE, "close",
+                       pFile ? pFile->zPath : 0, lineno);
+  }
+}
+
+/*
+** Set the pFile->lastErrno.  Do this in a subroutine as that provides
+** a convenient place to set a breakpoint.
+*/
+static void storeLastErrno(unixFile *pFile, int error){
+  pFile->lastErrno = error;
+}
+
+/*
+** Close all file descriptors accumulated in the unixInodeInfo->pUnused list.
+*/
+static void closePendingFds(unixFile *pFile){
+  unixInodeInfo *pInode = pFile->pInode;
+  UnixUnusedFd *p;
+  UnixUnusedFd *pNext;
+  assert( unixFileMutexHeld(pFile) );
+  for(p=pInode->pUnused; p; p=pNext){
+    pNext = p->pNext;
+    robust_close(pFile, p->fd, __LINE__);
+    sqlite3_free(p);
+  }
+  pInode->pUnused = 0;
+}
+
+/*
+** Release a unixInodeInfo structure previously allocated by findInodeInfo().
+**
+** The global mutex must be held when this routine is called, but the mutex
+** on the inode being deleted must NOT be held.
+*/
+static void releaseInodeInfo(unixFile *pFile){
+  unixInodeInfo *pInode = pFile->pInode;
+  assert( unixMutexHeld() );
+  assert( unixFileMutexNotheld(pFile) );
+  if( ALWAYS(pInode) ){
+    pInode->nRef--;
+    if( pInode->nRef==0 ){
+      assert( pInode->pShmNode==0 );
+      sqlite3_mutex_enter(pInode->pLockMutex);
+      closePendingFds(pFile);
+      sqlite3_mutex_leave(pInode->pLockMutex);
+      if( pInode->pPrev ){
+        assert( pInode->pPrev->pNext==pInode );
+        pInode->pPrev->pNext = pInode->pNext;
+      }else{
+        assert( inodeList==pInode );
+        inodeList = pInode->pNext;
+      }
+      if( pInode->pNext ){
+        assert( pInode->pNext->pPrev==pInode );
+        pInode->pNext->pPrev = pInode->pPrev;
+      }
+      sqlite3_mutex_free(pInode->pLockMutex);
+      sqlite3_free(pInode);
+    }
+  }
+}
+
+/*
+** Given a file descriptor, locate the unixInodeInfo object that
+** describes that file descriptor.  Create a new one if necessary.  The
+** return value might be uninitialized if an error occurs.
+**
+** The global mutex must held when calling this routine.
+**
+** Return an appropriate error code.
+*/
+static int findInodeInfo(
+  unixFile *pFile,               /* Unix file with file desc used in the key */
+  unixInodeInfo **ppInode        /* Return the unixInodeInfo object here */
+){
+  int rc;                        /* System call return code */
+  int fd;                        /* The file descriptor for pFile */
+  struct unixFileId fileId;      /* Lookup key for the unixInodeInfo */
+  struct stat statbuf;           /* Low-level file information */
+  unixInodeInfo *pInode = 0;     /* Candidate unixInodeInfo object */
+
+  assert( unixMutexHeld() );
+
+  /* Get low-level information about the file that we can used to
+  ** create a unique name for the file.
+  */
+  fd = pFile->h;
+  rc = osFstat(fd, &statbuf);
+  if( rc!=0 ){
+    storeLastErrno(pFile, errno);
+#if defined(EOVERFLOW) && defined(SQLITE_DISABLE_LFS)
+    if( pFile->lastErrno==EOVERFLOW ) return SQLITE_NOLFS;
+#endif
+    return SQLITE_IOERR;
+  }
+
+#ifdef __APPLE__
+  /* On OS X on an msdos filesystem, the inode number is reported
+  ** incorrectly for zero-size files.  See ticket #3260.  To work
+  ** around this problem (we consider it a bug in OS X, not SQLite)
+  ** we always increase the file size to 1 by writing a single byte
+  ** prior to accessing the inode number.  The one byte written is
+  ** an ASCII 'S' character which also happens to be the first byte
+  ** in the header of every SQLite database.  In this way, if there
+  ** is a race condition such that another thread has already populated
+  ** the first page of the database, no damage is done.
+  */
+  if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){
+    do{ rc = osWrite(fd, "S", 1); }while( rc<0 && errno==EINTR );
+    if( rc!=1 ){
+      storeLastErrno(pFile, errno);
+      return SQLITE_IOERR;
+    }
+    rc = osFstat(fd, &statbuf);
+    if( rc!=0 ){
+      storeLastErrno(pFile, errno);
+      return SQLITE_IOERR;
+    }
+  }
+#endif
+
+  memset(&fileId, 0, sizeof(fileId));
+  fileId.dev = statbuf.st_dev;
+#if OS_VXWORKS
+  fileId.pId = pFile->pId;
+#else
+  fileId.ino = (u64)statbuf.st_ino;
+#endif
+  assert( unixMutexHeld() );
+  pInode = inodeList;
+  while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){
+    pInode = pInode->pNext;
+  }
+  if( pInode==0 ){
+    pInode = sqlite3_malloc64( sizeof(*pInode) );
+    if( pInode==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    memset(pInode, 0, sizeof(*pInode));
+    memcpy(&pInode->fileId, &fileId, sizeof(fileId));
+    if( sqlite3GlobalConfig.bCoreMutex ){
+      pInode->pLockMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+      if( pInode->pLockMutex==0 ){
+        sqlite3_free(pInode);
+        return SQLITE_NOMEM_BKPT;
+      }
+    }
+    pInode->nRef = 1;
+    assert( unixMutexHeld() );
+    pInode->pNext = inodeList;
+    pInode->pPrev = 0;
+    if( inodeList ) inodeList->pPrev = pInode;
+    inodeList = pInode;
+  }else{
+    pInode->nRef++;
+  }
+  *ppInode = pInode;
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if pFile has been renamed or unlinked since it was first opened.
+*/
+static int fileHasMoved(unixFile *pFile){
+#if OS_VXWORKS
+  return pFile->pInode!=0 && pFile->pId!=pFile->pInode->fileId.pId;
+#else
+  struct stat buf;
+  return pFile->pInode!=0 &&
+      (osStat(pFile->zPath, &buf)!=0
+         || (u64)buf.st_ino!=pFile->pInode->fileId.ino);
+#endif
+}
+
+
+/*
+** Check a unixFile that is a database.  Verify the following:
+**
+** (1) There is exactly one hard link on the file
+** (2) The file is not a symbolic link
+** (3) The file has not been renamed or unlinked
+**
+** Issue sqlite3_log(SQLITE_WARNING,...) messages if anything is not right.
+*/
+static void verifyDbFile(unixFile *pFile){
+  struct stat buf;
+  int rc;
+
+  /* These verifications occurs for the main database only */
+  if( pFile->ctrlFlags & UNIXFILE_NOLOCK ) return;
+
+  rc = osFstat(pFile->h, &buf);
+  if( rc!=0 ){
+    sqlite3_log(SQLITE_WARNING, "cannot fstat db file %s", pFile->zPath);
+    return;
+  }
+  if( buf.st_nlink==0 ){
+    sqlite3_log(SQLITE_WARNING, "file unlinked while open: %s", pFile->zPath);
+    return;
+  }
+  if( buf.st_nlink>1 ){
+    sqlite3_log(SQLITE_WARNING, "multiple links to file: %s", pFile->zPath);
+    return;
+  }
+  if( fileHasMoved(pFile) ){
+    sqlite3_log(SQLITE_WARNING, "file renamed while open: %s", pFile->zPath);
+    return;
+  }
+}
+
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
+  int rc = SQLITE_OK;
+  int reserved = 0;
+  unixFile *pFile = (unixFile*)id;
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  assert( pFile );
+  assert( pFile->eFileLock<=SHARED_LOCK );
+  sqlite3_mutex_enter(pFile->pInode->pLockMutex);
+
+  /* Check if a thread in this process holds such a lock */
+  if( pFile->pInode->eFileLock>SHARED_LOCK ){
+    reserved = 1;
+  }
+
+  /* Otherwise see if some other process holds it.
+  */
+#ifndef __DJGPP__
+  if( !reserved && !pFile->pInode->bProcessLock ){
+    struct flock lock;
+    lock.l_whence = SEEK_SET;
+    lock.l_start = RESERVED_BYTE;
+    lock.l_len = 1;
+    lock.l_type = F_WRLCK;
+    if( osFcntl(pFile->h, F_GETLK, &lock) ){
+      rc = SQLITE_IOERR_CHECKRESERVEDLOCK;
+      storeLastErrno(pFile, errno);
+    } else if( lock.l_type!=F_UNLCK ){
+      reserved = 1;
+    }
+  }
+#endif
+
+  sqlite3_mutex_leave(pFile->pInode->pLockMutex);
+  OSTRACE(("TEST WR-LOCK %d %d %d (unix)\n", pFile->h, rc, reserved));
+
+  *pResOut = reserved;
+  return rc;
+}
+
+/* Forward declaration*/
+static int unixSleep(sqlite3_vfs*,int);
+
+/*
+** Set a posix-advisory-lock.
+**
+** There are two versions of this routine.  If compiled with
+** SQLITE_ENABLE_SETLK_TIMEOUT then the routine has an extra parameter
+** which is a pointer to a unixFile.  If the unixFile->iBusyTimeout
+** value is set, then it is the number of milliseconds to wait before
+** failing the lock.  The iBusyTimeout value is always reset back to
+** zero on each call.
+**
+** If SQLITE_ENABLE_SETLK_TIMEOUT is not defined, then do a non-blocking
+** attempt to set the lock.
+*/
+#ifndef SQLITE_ENABLE_SETLK_TIMEOUT
+# define osSetPosixAdvisoryLock(h,x,t) osFcntl(h,F_SETLK,x)
+#else
+static int osSetPosixAdvisoryLock(
+  int h,                /* The file descriptor on which to take the lock */
+  struct flock *pLock,  /* The description of the lock */
+  unixFile *pFile       /* Structure holding timeout value */
+){
+  int tm = pFile->iBusyTimeout;
+  int rc = osFcntl(h,F_SETLK,pLock);
+  while( rc<0 && tm>0 ){
+    /* On systems that support some kind of blocking file lock with a timeout,
+    ** make appropriate changes here to invoke that blocking file lock.  On
+    ** generic posix, however, there is no such API.  So we simply try the
+    ** lock once every millisecond until either the timeout expires, or until
+    ** the lock is obtained. */
+    unixSleep(0,1000);
+    rc = osFcntl(h,F_SETLK,pLock);
+    tm--;
+  }
+  return rc;
+}
+#endif /* SQLITE_ENABLE_SETLK_TIMEOUT */
+
+
+/*
+** Attempt to set a system-lock on the file pFile.  The lock is
+** described by pLock.
+**
+** If the pFile was opened read/write from unix-excl, then the only lock
+** ever obtained is an exclusive lock, and it is obtained exactly once
+** the first time any lock is attempted.  All subsequent system locking
+** operations become no-ops.  Locking operations still happen internally,
+** in order to coordinate access between separate database connections
+** within this process, but all of that is handled in memory and the
+** operating system does not participate.
+**
+** This function is a pass-through to fcntl(F_SETLK) if pFile is using
+** any VFS other than "unix-excl" or if pFile is opened on "unix-excl"
+** and is read-only.
+**
+** Zero is returned if the call completes successfully, or -1 if a call
+** to fcntl() fails. In this case, errno is set appropriately (by fcntl()).
+*/
+static int unixFileLock(unixFile *pFile, struct flock *pLock){
+  int rc;
+  unixInodeInfo *pInode = pFile->pInode;
+  assert( pInode!=0 );
+  assert( sqlite3_mutex_held(pInode->pLockMutex) );
+  if( (pFile->ctrlFlags & (UNIXFILE_EXCL|UNIXFILE_RDONLY))==UNIXFILE_EXCL ){
+    if( pInode->bProcessLock==0 ){
+      struct flock lock;
+      /* assert( pInode->nLock==0 ); <-- Not true if unix-excl READONLY used */
+      lock.l_whence = SEEK_SET;
+      lock.l_start = SHARED_FIRST;
+      lock.l_len = SHARED_SIZE;
+      lock.l_type = F_WRLCK;
+      rc = osSetPosixAdvisoryLock(pFile->h, &lock, pFile);
+      if( rc<0 ) return rc;
+      pInode->bProcessLock = 1;
+      pInode->nLock++;
+    }else{
+      rc = 0;
+    }
+  }else{
+    rc = osSetPosixAdvisoryLock(pFile->h, pLock, pFile);
+  }
+  return rc;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int unixLock(sqlite3_file *id, int eFileLock){
+  /* The following describes the implementation of the various locks and
+  ** lock transitions in terms of the POSIX advisory shared and exclusive
+  ** lock primitives (called read-locks and write-locks below, to avoid
+  ** confusion with SQLite lock names). The algorithms are complicated
+  ** slightly in order to be compatible with Windows95 systems simultaneously
+  ** accessing the same database file, in case that is ever required.
+  **
+  ** Symbols defined in os.h identify the 'pending byte' and the 'reserved
+  ** byte', each single bytes at well known offsets, and the 'shared byte
+  ** range', a range of 510 bytes at a well known offset.
+  **
+  ** To obtain a SHARED lock, a read-lock is obtained on the 'pending
+  ** byte'.  If this is successful, 'shared byte range' is read-locked
+  ** and the lock on the 'pending byte' released.  (Legacy note:  When
+  ** SQLite was first developed, Windows95 systems were still very common,
+  ** and Windows95 lacks a shared-lock capability.  So on Windows95, a
+  ** single randomly selected by from the 'shared byte range' is locked.
+  ** Windows95 is now pretty much extinct, but this work-around for the
+  ** lack of shared-locks on Windows95 lives on, for backwards
+  ** compatibility.)
+  **
+  ** A process may only obtain a RESERVED lock after it has a SHARED lock.
+  ** A RESERVED lock is implemented by grabbing a write-lock on the
+  ** 'reserved byte'.
+  **
+  ** An EXCLUSIVE lock may only be requested after either a SHARED or
+  ** RESERVED lock is held. An EXCLUSIVE lock is implemented by obtaining
+  ** a write-lock on the entire 'shared byte range'. Since all other locks
+  ** require a read-lock on one of the bytes within this range, this ensures
+  ** that no other locks are held on the database.
+  **
+  ** If a process that holds a RESERVED lock requests an EXCLUSIVE, then
+  ** a PENDING lock is obtained first. A PENDING lock is implemented by
+  ** obtaining a write-lock on the 'pending byte'. This ensures that no new
+  ** SHARED locks can be obtained, but existing SHARED locks are allowed to
+  ** persist. If the call to this function fails to obtain the EXCLUSIVE
+  ** lock in this case, it holds the PENDING lock instead. The client may
+  ** then re-attempt the EXCLUSIVE lock later on, after existing SHARED
+  ** locks have cleared.
+  */
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode;
+  struct flock lock;
+  int tErrno = 0;
+
+  assert( pFile );
+  OSTRACE(("LOCK    %d %s was %s(%s,%d) pid=%d (unix)\n", pFile->h,
+      azFileLock(eFileLock), azFileLock(pFile->eFileLock),
+      azFileLock(pFile->pInode->eFileLock), pFile->pInode->nShared,
+      osGetpid(0)));
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** unixFile, do nothing. Don't use the end_lock: exit path, as
+  ** unixEnterMutex() hasn't been called yet.
+  */
+  if( pFile->eFileLock>=eFileLock ){
+    OSTRACE(("LOCK    %d %s ok (already held) (unix)\n", pFile->h,
+            azFileLock(eFileLock)));
+    return SQLITE_OK;
+  }
+
+  /* Make sure the locking sequence is correct.
+  **  (1) We never move from unlocked to anything higher than shared lock.
+  **  (2) SQLite never explicitly requests a pending lock.
+  **  (3) A shared lock is always held when a reserve lock is requested.
+  */
+  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
+  assert( eFileLock!=PENDING_LOCK );
+  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );
+
+  /* This mutex is needed because pFile->pInode is shared across threads
+  */
+  pInode = pFile->pInode;
+  sqlite3_mutex_enter(pInode->pLockMutex);
+
+  /* If some thread using this PID has a lock via a different unixFile*
+  ** handle that precludes the requested lock, return BUSY.
+  */
+  if( (pFile->eFileLock!=pInode->eFileLock &&
+          (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK))
+  ){
+    rc = SQLITE_BUSY;
+    goto end_lock;
+  }
+
+  /* If a SHARED lock is requested, and some thread using this PID already
+  ** has a SHARED or RESERVED lock, then increment reference counts and
+  ** return SQLITE_OK.
+  */
+  if( eFileLock==SHARED_LOCK &&
+      (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){
+    assert( eFileLock==SHARED_LOCK );
+    assert( pFile->eFileLock==0 );
+    assert( pInode->nShared>0 );
+    pFile->eFileLock = SHARED_LOCK;
+    pInode->nShared++;
+    pInode->nLock++;
+    goto end_lock;
+  }
+
+
+  /* A PENDING lock is needed before acquiring a SHARED lock and before
+  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
+  ** be released.
+  */
+  lock.l_len = 1L;
+  lock.l_whence = SEEK_SET;
+  if( eFileLock==SHARED_LOCK
+   || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock==RESERVED_LOCK)
+  ){
+    lock.l_type = (eFileLock==SHARED_LOCK?F_RDLCK:F_WRLCK);
+    lock.l_start = PENDING_BYTE;
+    if( unixFileLock(pFile, &lock) ){
+      tErrno = errno;
+      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+      if( rc!=SQLITE_BUSY ){
+        storeLastErrno(pFile, tErrno);
+      }
+      goto end_lock;
+    }else if( eFileLock==EXCLUSIVE_LOCK ){
+      pFile->eFileLock = PENDING_LOCK;
+      pInode->eFileLock = PENDING_LOCK;
+    }
+  }
+
+
+  /* If control gets to this point, then actually go ahead and make
+  ** operating system calls for the specified lock.
+  */
+  if( eFileLock==SHARED_LOCK ){
+    assert( pInode->nShared==0 );
+    assert( pInode->eFileLock==0 );
+    assert( rc==SQLITE_OK );
+
+    /* Now get the read-lock */
+    lock.l_start = SHARED_FIRST;
+    lock.l_len = SHARED_SIZE;
+    if( unixFileLock(pFile, &lock) ){
+      tErrno = errno;
+      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+    }
+
+    /* Drop the temporary PENDING lock */
+    lock.l_start = PENDING_BYTE;
+    lock.l_len = 1L;
+    lock.l_type = F_UNLCK;
+    if( unixFileLock(pFile, &lock) && rc==SQLITE_OK ){
+      /* This could happen with a network mount */
+      tErrno = errno;
+      rc = SQLITE_IOERR_UNLOCK;
+    }
+
+    if( rc ){
+      if( rc!=SQLITE_BUSY ){
+        storeLastErrno(pFile, tErrno);
+      }
+      goto end_lock;
+    }else{
+      pFile->eFileLock = SHARED_LOCK;
+      pInode->nLock++;
+      pInode->nShared = 1;
+    }
+  }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){
+    /* We are trying for an exclusive lock but another thread in this
+    ** same process is still holding a shared lock. */
+    rc = SQLITE_BUSY;
+  }else{
+    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
+    ** assumed that there is a SHARED or greater lock on the file
+    ** already.
+    */
+    assert( 0!=pFile->eFileLock );
+    lock.l_type = F_WRLCK;
+
+    assert( eFileLock==RESERVED_LOCK || eFileLock==EXCLUSIVE_LOCK );
+    if( eFileLock==RESERVED_LOCK ){
+      lock.l_start = RESERVED_BYTE;
+      lock.l_len = 1L;
+    }else{
+      lock.l_start = SHARED_FIRST;
+      lock.l_len = SHARED_SIZE;
+    }
+
+    if( unixFileLock(pFile, &lock) ){
+      tErrno = errno;
+      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+      if( rc!=SQLITE_BUSY ){
+        storeLastErrno(pFile, tErrno);
+      }
+    }
+  }
+
+
+#ifdef SQLITE_DEBUG
+  /* Set up the transaction-counter change checking flags when
+  ** transitioning from a SHARED to a RESERVED lock.  The change
+  ** from SHARED to RESERVED marks the beginning of a normal
+  ** write operation (not a hot journal rollback).
+  */
+  if( rc==SQLITE_OK
+   && pFile->eFileLock<=SHARED_LOCK
+   && eFileLock==RESERVED_LOCK
+  ){
+    pFile->transCntrChng = 0;
+    pFile->dbUpdate = 0;
+    pFile->inNormalWrite = 1;
+  }
+#endif
+
+  if( rc==SQLITE_OK ){
+    pFile->eFileLock = eFileLock;
+    pInode->eFileLock = eFileLock;
+  }
+
+end_lock:
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  OSTRACE(("LOCK    %d %s %s (unix)\n", pFile->h, azFileLock(eFileLock),
+      rc==SQLITE_OK ? "ok" : "failed"));
+  return rc;
+}
+
+/*
+** Add the file descriptor used by file handle pFile to the corresponding
+** pUnused list.
+*/
+static void setPendingFd(unixFile *pFile){
+  unixInodeInfo *pInode = pFile->pInode;
+  UnixUnusedFd *p = pFile->pPreallocatedUnused;
+  assert( unixFileMutexHeld(pFile) );
+  p->pNext = pInode->pUnused;
+  pInode->pUnused = p;
+  pFile->h = -1;
+  pFile->pPreallocatedUnused = 0;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+**
+** If handleNFSUnlock is true, then on downgrading an EXCLUSIVE_LOCK to SHARED
+** the byte range is divided into 2 parts and the first part is unlocked then
+** set to a read lock, then the other part is simply unlocked.  This works
+** around a bug in BSD NFS lockd (also seen on MacOSX 10.3+) that fails to
+** remove the write lock on a region when a read lock is set.
+*/
+static int posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
+  unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode;
+  struct flock lock;
+  int rc = SQLITE_OK;
+
+  assert( pFile );
+  OSTRACE(("UNLOCK  %d %d was %d(%d,%d) pid=%d (unix)\n", pFile->h, eFileLock,
+      pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared,
+      osGetpid(0)));
+
+  assert( eFileLock<=SHARED_LOCK );
+  if( pFile->eFileLock<=eFileLock ){
+    return SQLITE_OK;
+  }
+  pInode = pFile->pInode;
+  sqlite3_mutex_enter(pInode->pLockMutex);
+  assert( pInode->nShared!=0 );
+  if( pFile->eFileLock>SHARED_LOCK ){
+    assert( pInode->eFileLock==pFile->eFileLock );
+
+#ifdef SQLITE_DEBUG
+    /* When reducing a lock such that other processes can start
+    ** reading the database file again, make sure that the
+    ** transaction counter was updated if any part of the database
+    ** file changed.  If the transaction counter is not updated,
+    ** other connections to the same file might not realize that
+    ** the file has changed and hence might not know to flush their
+    ** cache.  The use of a stale cache can lead to database corruption.
+    */
+    pFile->inNormalWrite = 0;
+#endif
+
+    /* downgrading to a shared lock on NFS involves clearing the write lock
+    ** before establishing the readlock - to avoid a race condition we downgrade
+    ** the lock in 2 blocks, so that part of the range will be covered by a
+    ** write lock until the rest is covered by a read lock:
+    **  1:   [WWWWW]
+    **  2:   [....W]
+    **  3:   [RRRRW]
+    **  4:   [RRRR.]
+    */
+    if( eFileLock==SHARED_LOCK ){
+#if !defined(__APPLE__) || !SQLITE_ENABLE_LOCKING_STYLE
+      (void)handleNFSUnlock;
+      assert( handleNFSUnlock==0 );
+#endif
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+      if( handleNFSUnlock ){
+        int tErrno;               /* Error code from system call errors */
+        off_t divSize = SHARED_SIZE - 1;
+
+        lock.l_type = F_UNLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = divSize;
+        if( unixFileLock(pFile, &lock)==(-1) ){
+          tErrno = errno;
+          rc = SQLITE_IOERR_UNLOCK;
+          storeLastErrno(pFile, tErrno);
+          goto end_unlock;
+        }
+        lock.l_type = F_RDLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = divSize;
+        if( unixFileLock(pFile, &lock)==(-1) ){
+          tErrno = errno;
+          rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
+          if( IS_LOCK_ERROR(rc) ){
+            storeLastErrno(pFile, tErrno);
+          }
+          goto end_unlock;
+        }
+        lock.l_type = F_UNLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST+divSize;
+        lock.l_len = SHARED_SIZE-divSize;
+        if( unixFileLock(pFile, &lock)==(-1) ){
+          tErrno = errno;
+          rc = SQLITE_IOERR_UNLOCK;
+          storeLastErrno(pFile, tErrno);
+          goto end_unlock;
+        }
+      }else
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+      {
+        lock.l_type = F_RDLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = SHARED_SIZE;
+        if( unixFileLock(pFile, &lock) ){
+          /* In theory, the call to unixFileLock() cannot fail because another
+          ** process is holding an incompatible lock. If it does, this
+          ** indicates that the other process is not following the locking
+          ** protocol. If this happens, return SQLITE_IOERR_RDLOCK. Returning
+          ** SQLITE_BUSY would confuse the upper layer (in practice it causes
+          ** an assert to fail). */
+          rc = SQLITE_IOERR_RDLOCK;
+          storeLastErrno(pFile, errno);
+          goto end_unlock;
+        }
+      }
+    }
+    lock.l_type = F_UNLCK;
+    lock.l_whence = SEEK_SET;
+    lock.l_start = PENDING_BYTE;
+    lock.l_len = 2L;  assert( PENDING_BYTE+1==RESERVED_BYTE );
+    if( unixFileLock(pFile, &lock)==0 ){
+      pInode->eFileLock = SHARED_LOCK;
+    }else{
+      rc = SQLITE_IOERR_UNLOCK;
+      storeLastErrno(pFile, errno);
+      goto end_unlock;
+    }
+  }
+  if( eFileLock==NO_LOCK ){
+    /* Decrement the shared lock counter.  Release the lock using an
+    ** OS call only when all threads in this same process have released
+    ** the lock.
+    */
+    pInode->nShared--;
+    if( pInode->nShared==0 ){
+      lock.l_type = F_UNLCK;
+      lock.l_whence = SEEK_SET;
+      lock.l_start = lock.l_len = 0L;
+      if( unixFileLock(pFile, &lock)==0 ){
+        pInode->eFileLock = NO_LOCK;
+      }else{
+        rc = SQLITE_IOERR_UNLOCK;
+        storeLastErrno(pFile, errno);
+        pInode->eFileLock = NO_LOCK;
+        pFile->eFileLock = NO_LOCK;
+      }
+    }
+
+    /* Decrement the count of locks against this same file.  When the
+    ** count reaches zero, close any other file descriptors whose close
+    ** was deferred because of outstanding locks.
+    */
+    pInode->nLock--;
+    assert( pInode->nLock>=0 );
+    if( pInode->nLock==0 ) closePendingFds(pFile);
+  }
+
+end_unlock:
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  if( rc==SQLITE_OK ){
+    pFile->eFileLock = eFileLock;
+  }
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int unixUnlock(sqlite3_file *id, int eFileLock){
+#if SQLITE_MAX_MMAP_SIZE>0
+  assert( eFileLock==SHARED_LOCK || ((unixFile *)id)->nFetchOut==0 );
+#endif
+  return posixUnlock(id, eFileLock, 0);
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+static int unixMapfile(unixFile *pFd, i64 nByte);
+static void unixUnmapfile(unixFile *pFd);
+#endif
+
+/*
+** This function performs the parts of the "close file" operation
+** common to all locking schemes. It closes the directory and file
+** handles, if they are valid, and sets all fields of the unixFile
+** structure to 0.
+**
+** It is *not* necessary to hold the mutex when this routine is called,
+** even on VxWorks.  A mutex will be acquired on VxWorks by the
+** vxworksReleaseFileId() routine.
+*/
+static int closeUnixFile(sqlite3_file *id){
+  unixFile *pFile = (unixFile*)id;
+#if SQLITE_MAX_MMAP_SIZE>0
+  unixUnmapfile(pFile);
+#endif
+  if( pFile->h>=0 ){
+    robust_close(pFile, pFile->h, __LINE__);
+    pFile->h = -1;
+  }
+#if OS_VXWORKS
+  if( pFile->pId ){
+    if( pFile->ctrlFlags & UNIXFILE_DELETE ){
+      osUnlink(pFile->pId->zCanonicalName);
+    }
+    vxworksReleaseFileId(pFile->pId);
+    pFile->pId = 0;
+  }
+#endif
+#ifdef SQLITE_UNLINK_AFTER_CLOSE
+  if( pFile->ctrlFlags & UNIXFILE_DELETE ){
+    osUnlink(pFile->zPath);
+    sqlite3_free(*(char**)&pFile->zPath);
+    pFile->zPath = 0;
+  }
+#endif
+  OSTRACE(("CLOSE   %-3d\n", pFile->h));
+  OpenCounter(-1);
+  sqlite3_free(pFile->pPreallocatedUnused);
+  memset(pFile, 0, sizeof(unixFile));
+  return SQLITE_OK;
+}
+
+/*
+** Close a file.
+*/
+static int unixClose(sqlite3_file *id){
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile *)id;
+  unixInodeInfo *pInode = pFile->pInode;
+
+  assert( pInode!=0 );
+  verifyDbFile(pFile);
+  unixUnlock(id, NO_LOCK);
+  assert( unixFileMutexNotheld(pFile) );
+  unixEnterMutex();
+
+  /* unixFile.pInode is always valid here. Otherwise, a different close
+  ** routine (e.g. nolockClose()) would be called instead.
+  */
+  assert( pFile->pInode->nLock>0 || pFile->pInode->bProcessLock==0 );
+  sqlite3_mutex_enter(pInode->pLockMutex);
+  if( pInode->nLock ){
+    /* If there are outstanding locks, do not actually close the file just
+    ** yet because that would clear those locks.  Instead, add the file
+    ** descriptor to pInode->pUnused list.  It will be automatically closed
+    ** when the last lock is cleared.
+    */
+    setPendingFd(pFile);
+  }
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  releaseInodeInfo(pFile);
+  assert( pFile->pShm==0 );
+  rc = closeUnixFile(id);
+  unixLeaveMutex();
+  return rc;
+}
+
+/************** End of the posix advisory lock implementation *****************
+******************************************************************************/
+
+/******************************************************************************
+****************************** No-op Locking **********************************
+**
+** Of the various locking implementations available, this is by far the
+** simplest:  locking is ignored.  No attempt is made to lock the database
+** file for reading or writing.
+**
+** This locking mode is appropriate for use on read-only databases
+** (ex: databases that are burned into CD-ROM, for example.)  It can
+** also be used if the application employs some external mechanism to
+** prevent simultaneous access of the same database by two or more
+** database connections.  But there is a serious risk of database
+** corruption if this locking mode is used in situations where multiple
+** database connections are accessing the same database file at the same
+** time and one or more of those connections are writing.
+*/
+
+static int nolockCheckReservedLock(sqlite3_file *NotUsed, int *pResOut){
+  UNUSED_PARAMETER(NotUsed);
+  *pResOut = 0;
+  return SQLITE_OK;
+}
+static int nolockLock(sqlite3_file *NotUsed, int NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  return SQLITE_OK;
+}
+static int nolockUnlock(sqlite3_file *NotUsed, int NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  return SQLITE_OK;
+}
+
+/*
+** Close the file.
+*/
+static int nolockClose(sqlite3_file *id) {
+  return closeUnixFile(id);
+}
+
+/******************* End of the no-op lock implementation *********************
+******************************************************************************/
+
+/******************************************************************************
+************************* Begin dot-file Locking ******************************
+**
+** The dotfile locking implementation uses the existence of separate lock
+** files (really a directory) to control access to the database.  This works
+** on just about every filesystem imaginable.  But there are serious downsides:
+**
+**    (1)  There is zero concurrency.  A single reader blocks all other
+**         connections from reading or writing the database.
+**
+**    (2)  An application crash or power loss can leave stale lock files
+**         sitting around that need to be cleared manually.
+**
+** Nevertheless, a dotlock is an appropriate locking mode for use if no
+** other locking strategy is available.
+**
+** Dotfile locking works by creating a subdirectory in the same directory as
+** the database and with the same name but with a ".lock" extension added.
+** The existence of a lock directory implies an EXCLUSIVE lock.  All other
+** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
+*/
+
+/*
+** The file suffix added to the data base filename in order to create the
+** lock directory.
+*/
+#define DOTLOCK_SUFFIX ".lock"
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If the caller holds a SHARED
+** or greater lock when it is called, then it is assumed that no other
+** client may hold RESERVED. Or, if the caller holds no lock, then it
+** is assumed another client holds RESERVED if the lock-file exists.
+*/
+static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) {
+  unixFile *pFile = (unixFile*)id;
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  if( pFile->eFileLock>=SHARED_LOCK ){
+    *pResOut = 0;
+  }else{
+    *pResOut = osAccess((const char*)pFile->lockingContext, 0)==0;
+  }
+  OSTRACE(("TEST WR-LOCK %d %d %d (dotlock)\n", pFile->h, 0, *pResOut));
+  return SQLITE_OK;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+**
+** With dotfile locking, we really only support state (4): EXCLUSIVE.
+** But we track the other locking levels internally.
+*/
+static int dotlockLock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  char *zLockFile = (char *)pFile->lockingContext;
+  int rc = SQLITE_OK;
+
+
+  /* If we have any lock, then the lock file already exists.  All we have
+  ** to do is adjust our internal record of the lock level.
+  */
+  if( pFile->eFileLock > NO_LOCK ){
+    pFile->eFileLock = eFileLock;
+    /* Always update the timestamp on the old file */
+#ifdef HAVE_UTIME
+    utime(zLockFile, NULL);
+#else
+    utimes(zLockFile, NULL);
+#endif
+    return SQLITE_OK;
+  }
+
+  /* grab an exclusive lock */
+  rc = osMkdir(zLockFile, 0777);
+  if( rc<0 ){
+    /* failed to open/create the lock directory */
+    int tErrno = errno;
+    if( EEXIST == tErrno ){
+      rc = SQLITE_BUSY;
+    } else {
+      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+      if( rc!=SQLITE_BUSY ){
+        storeLastErrno(pFile, tErrno);
+      }
+    }
+    return rc;
+  }
+
+  /* got it, set the type and return ok */
+  pFile->eFileLock = eFileLock;
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+**
+** When the locking level reaches NO_LOCK, delete the lock file.
+*/
+static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  char *zLockFile = (char *)pFile->lockingContext;
+  int rc;
+
+  assert( pFile );
+  OSTRACE(("UNLOCK  %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock,
+           pFile->eFileLock, osGetpid(0)));
+  assert( eFileLock<=SHARED_LOCK );
+
+  /* no-op if possible */
+  if( pFile->eFileLock==eFileLock ){
+    return SQLITE_OK;
+  }
+
+  /* To downgrade to shared, simply update our internal notion of the
+  ** lock state.  No need to mess with the file on disk.
+  */
+  if( eFileLock==SHARED_LOCK ){
+    pFile->eFileLock = SHARED_LOCK;
+    return SQLITE_OK;
+  }
+
+  /* To fully unlock the database, delete the lock file */
+  assert( eFileLock==NO_LOCK );
+  rc = osRmdir(zLockFile);
+  if( rc<0 ){
+    int tErrno = errno;
+    if( tErrno==ENOENT ){
+      rc = SQLITE_OK;
+    }else{
+      rc = SQLITE_IOERR_UNLOCK;
+      storeLastErrno(pFile, tErrno);
+    }
+    return rc;
+  }
+  pFile->eFileLock = NO_LOCK;
+  return SQLITE_OK;
+}
+
+/*
+** Close a file.  Make sure the lock has been released before closing.
+*/
+static int dotlockClose(sqlite3_file *id) {
+  unixFile *pFile = (unixFile*)id;
+  assert( id!=0 );
+  dotlockUnlock(id, NO_LOCK);
+  sqlite3_free(pFile->lockingContext);
+  return closeUnixFile(id);
+}
+/****************** End of the dot-file lock implementation *******************
+******************************************************************************/
+
+/******************************************************************************
+************************** Begin flock Locking ********************************
+**
+** Use the flock() system call to do file locking.
+**
+** flock() locking is like dot-file locking in that the various
+** fine-grain locking levels supported by SQLite are collapsed into
+** a single exclusive lock.  In other words, SHARED, RESERVED, and
+** PENDING locks are the same thing as an EXCLUSIVE lock.  SQLite
+** still works when you do this, but concurrency is reduced since
+** only a single process can be reading the database at a time.
+**
+** Omit this section if SQLITE_ENABLE_LOCKING_STYLE is turned off
+*/
+#if SQLITE_ENABLE_LOCKING_STYLE
+
+/*
+** Retry flock() calls that fail with EINTR
+*/
+#ifdef EINTR
+static int robust_flock(int fd, int op){
+  int rc;
+  do{ rc = flock(fd,op); }while( rc<0 && errno==EINTR );
+  return rc;
+}
+#else
+# define robust_flock(a,b) flock(a,b)
+#endif
+
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){
+#ifdef SQLITE_DEBUG
+  unixFile *pFile = (unixFile*)id;
+#else
+  UNUSED_PARAMETER(id);
+#endif
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  assert( pFile );
+  assert( pFile->eFileLock<=SHARED_LOCK );
+
+  /* The flock VFS only ever takes exclusive locks (see function flockLock).
+  ** Therefore, if this connection is holding any lock at all, no other
+  ** connection may be holding a RESERVED lock. So set *pResOut to 0
+  ** in this case.
+  **
+  ** Or, this connection may be holding no lock. In that case, set *pResOut to
+  ** 0 as well. The caller will then attempt to take an EXCLUSIVE lock on the
+  ** db in order to roll the hot journal back. If there is another connection
+  ** holding a lock, that attempt will fail and an SQLITE_BUSY returned to
+  ** the user. With other VFS, we try to avoid this, in order to allow a reader
+  ** to proceed while a writer is preparing its transaction. But that won't
+  ** work with the flock VFS - as it always takes EXCLUSIVE locks - so it is
+  ** not a problem in this case.  */
+  *pResOut = 0;
+
+  return SQLITE_OK;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** flock() only really support EXCLUSIVE locks.  We track intermediate
+** lock states in the sqlite3_file structure, but all locks SHARED or
+** above are really EXCLUSIVE locks and exclude all other processes from
+** access the file.
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int flockLock(sqlite3_file *id, int eFileLock) {
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+
+  assert( pFile );
+
+  /* if we already have a lock, it is exclusive.
+  ** Just adjust level and punt on outta here. */
+  if (pFile->eFileLock > NO_LOCK) {
+    pFile->eFileLock = eFileLock;
+    return SQLITE_OK;
+  }
+
+  /* grab an exclusive lock */
+
+  if (robust_flock(pFile->h, LOCK_EX | LOCK_NB)) {
+    int tErrno = errno;
+    /* didn't get, must be busy */
+    rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+    if( IS_LOCK_ERROR(rc) ){
+      storeLastErrno(pFile, tErrno);
+    }
+  } else {
+    /* got it, set the type and return ok */
+    pFile->eFileLock = eFileLock;
+  }
+  OSTRACE(("LOCK    %d %s %s (flock)\n", pFile->h, azFileLock(eFileLock),
+           rc==SQLITE_OK ? "ok" : "failed"));
+#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
+  if( (rc & 0xff) == SQLITE_IOERR ){
+    rc = SQLITE_BUSY;
+  }
+#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
+  return rc;
+}
+
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int flockUnlock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+
+  assert( pFile );
+  OSTRACE(("UNLOCK  %d %d was %d pid=%d (flock)\n", pFile->h, eFileLock,
+           pFile->eFileLock, osGetpid(0)));
+  assert( eFileLock<=SHARED_LOCK );
+
+  /* no-op if possible */
+  if( pFile->eFileLock==eFileLock ){
+    return SQLITE_OK;
+  }
+
+  /* shared can just be set because we always have an exclusive */
+  if (eFileLock==SHARED_LOCK) {
+    pFile->eFileLock = eFileLock;
+    return SQLITE_OK;
+  }
+
+  /* no, really, unlock. */
+  if( robust_flock(pFile->h, LOCK_UN) ){
+#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
+    return SQLITE_OK;
+#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
+    return SQLITE_IOERR_UNLOCK;
+  }else{
+    pFile->eFileLock = NO_LOCK;
+    return SQLITE_OK;
+  }
+}
+
+/*
+** Close a file.
+*/
+static int flockClose(sqlite3_file *id) {
+  assert( id!=0 );
+  flockUnlock(id, NO_LOCK);
+  return closeUnixFile(id);
+}
+
+#endif /* SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORK */
+
+/******************* End of the flock lock implementation *********************
+******************************************************************************/
+
+/******************************************************************************
+************************ Begin Named Semaphore Locking ************************
+**
+** Named semaphore locking is only supported on VxWorks.
+**
+** Semaphore locking is like dot-lock and flock in that it really only
+** supports EXCLUSIVE locking.  Only a single process can read or write
+** the database file at a time.  This reduces potential concurrency, but
+** makes the lock implementation much easier.
+*/
+#if OS_VXWORKS
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int semXCheckReservedLock(sqlite3_file *id, int *pResOut) {
+  int rc = SQLITE_OK;
+  int reserved = 0;
+  unixFile *pFile = (unixFile*)id;
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  assert( pFile );
+
+  /* Check if a thread in this process holds such a lock */
+  if( pFile->eFileLock>SHARED_LOCK ){
+    reserved = 1;
+  }
+
+  /* Otherwise see if some other process holds it. */
+  if( !reserved ){
+    sem_t *pSem = pFile->pInode->pSem;
+
+    if( sem_trywait(pSem)==-1 ){
+      int tErrno = errno;
+      if( EAGAIN != tErrno ){
+        rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK);
+        storeLastErrno(pFile, tErrno);
+      } else {
+        /* someone else has the lock when we are in NO_LOCK */
+        reserved = (pFile->eFileLock < SHARED_LOCK);
+      }
+    }else{
+      /* we could have it if we want it */
+      sem_post(pSem);
+    }
+  }
+  OSTRACE(("TEST WR-LOCK %d %d %d (sem)\n", pFile->h, rc, reserved));
+
+  *pResOut = reserved;
+  return rc;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** Semaphore locks only really support EXCLUSIVE locks.  We track intermediate
+** lock states in the sqlite3_file structure, but all locks SHARED or
+** above are really EXCLUSIVE locks and exclude all other processes from
+** access the file.
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int semXLock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  sem_t *pSem = pFile->pInode->pSem;
+  int rc = SQLITE_OK;
+
+  /* if we already have a lock, it is exclusive.
+  ** Just adjust level and punt on outta here. */
+  if (pFile->eFileLock > NO_LOCK) {
+    pFile->eFileLock = eFileLock;
+    rc = SQLITE_OK;
+    goto sem_end_lock;
+  }
+
+  /* lock semaphore now but bail out when already locked. */
+  if( sem_trywait(pSem)==-1 ){
+    rc = SQLITE_BUSY;
+    goto sem_end_lock;
+  }
+
+  /* got it, set the type and return ok */
+  pFile->eFileLock = eFileLock;
+
+ sem_end_lock:
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int semXUnlock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  sem_t *pSem = pFile->pInode->pSem;
+
+  assert( pFile );
+  assert( pSem );
+  OSTRACE(("UNLOCK  %d %d was %d pid=%d (sem)\n", pFile->h, eFileLock,
+           pFile->eFileLock, osGetpid(0)));
+  assert( eFileLock<=SHARED_LOCK );
+
+  /* no-op if possible */
+  if( pFile->eFileLock==eFileLock ){
+    return SQLITE_OK;
+  }
+
+  /* shared can just be set because we always have an exclusive */
+  if (eFileLock==SHARED_LOCK) {
+    pFile->eFileLock = eFileLock;
+    return SQLITE_OK;
+  }
+
+  /* no, really unlock. */
+  if ( sem_post(pSem)==-1 ) {
+    int rc, tErrno = errno;
+    rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
+    if( IS_LOCK_ERROR(rc) ){
+      storeLastErrno(pFile, tErrno);
+    }
+    return rc;
+  }
+  pFile->eFileLock = NO_LOCK;
+  return SQLITE_OK;
+}
+
+/*
+ ** Close a file.
+ */
+static int semXClose(sqlite3_file *id) {
+  if( id ){
+    unixFile *pFile = (unixFile*)id;
+    semXUnlock(id, NO_LOCK);
+    assert( pFile );
+    assert( unixFileMutexNotheld(pFile) );
+    unixEnterMutex();
+    releaseInodeInfo(pFile);
+    unixLeaveMutex();
+    closeUnixFile(id);
+  }
+  return SQLITE_OK;
+}
+
+#endif /* OS_VXWORKS */
+/*
+** Named semaphore locking is only available on VxWorks.
+**
+*************** End of the named semaphore lock implementation ****************
+******************************************************************************/
+
+
+/******************************************************************************
+*************************** Begin AFP Locking *********************************
+**
+** AFP is the Apple Filing Protocol.  AFP is a network filesystem found
+** on Apple Macintosh computers - both OS9 and OSX.
+**
+** Third-party implementations of AFP are available.  But this code here
+** only works on OSX.
+*/
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+/*
+** The afpLockingContext structure contains all afp lock specific state
+*/
+typedef struct afpLockingContext afpLockingContext;
+struct afpLockingContext {
+  int reserved;
+  const char *dbPath;             /* Name of the open file */
+};
+
+struct ByteRangeLockPB2
+{
+  unsigned long long offset;        /* offset to first byte to lock */
+  unsigned long long length;        /* nbr of bytes to lock */
+  unsigned long long retRangeStart; /* nbr of 1st byte locked if successful */
+  unsigned char unLockFlag;         /* 1 = unlock, 0 = lock */
+  unsigned char startEndFlag;       /* 1=rel to end of fork, 0=rel to start */
+  int fd;                           /* file desc to assoc this lock with */
+};
+
+#define afpfsByteRangeLock2FSCTL        _IOWR('z', 23, struct ByteRangeLockPB2)
+
+/*
+** This is a utility for setting or clearing a bit-range lock on an
+** AFP filesystem.
+**
+** Return SQLITE_OK on success, SQLITE_BUSY on failure.
+*/
+static int afpSetLock(
+  const char *path,              /* Name of the file to be locked or unlocked */
+  unixFile *pFile,               /* Open file descriptor on path */
+  unsigned long long offset,     /* First byte to be locked */
+  unsigned long long length,     /* Number of bytes to lock */
+  int setLockFlag                /* True to set lock.  False to clear lock */
+){
+  struct ByteRangeLockPB2 pb;
+  int err;
+
+  pb.unLockFlag = setLockFlag ? 0 : 1;
+  pb.startEndFlag = 0;
+  pb.offset = offset;
+  pb.length = length;
+  pb.fd = pFile->h;
+
+  OSTRACE(("AFPSETLOCK [%s] for %d%s in range %llx:%llx\n",
+    (setLockFlag?"ON":"OFF"), pFile->h, (pb.fd==-1?"[testval-1]":""),
+    offset, length));
+  err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0);
+  if ( err==-1 ) {
+    int rc;
+    int tErrno = errno;
+    OSTRACE(("AFPSETLOCK failed to fsctl() '%s' %d %s\n",
+             path, tErrno, strerror(tErrno)));
+#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS
+    rc = SQLITE_BUSY;
+#else
+    rc = sqliteErrorFromPosixError(tErrno,
+                    setLockFlag ? SQLITE_IOERR_LOCK : SQLITE_IOERR_UNLOCK);
+#endif /* SQLITE_IGNORE_AFP_LOCK_ERRORS */
+    if( IS_LOCK_ERROR(rc) ){
+      storeLastErrno(pFile, tErrno);
+    }
+    return rc;
+  } else {
+    return SQLITE_OK;
+  }
+}
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int afpCheckReservedLock(sqlite3_file *id, int *pResOut){
+  int rc = SQLITE_OK;
+  int reserved = 0;
+  unixFile *pFile = (unixFile*)id;
+  afpLockingContext *context;
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  assert( pFile );
+  context = (afpLockingContext *) pFile->lockingContext;
+  if( context->reserved ){
+    *pResOut = 1;
+    return SQLITE_OK;
+  }
+  sqlite3_mutex_enter(pFile->pInode->pLockMutex);
+  /* Check if a thread in this process holds such a lock */
+  if( pFile->pInode->eFileLock>SHARED_LOCK ){
+    reserved = 1;
+  }
+
+  /* Otherwise see if some other process holds it.
+   */
+  if( !reserved ){
+    /* lock the RESERVED byte */
+    int lrc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1);
+    if( SQLITE_OK==lrc ){
+      /* if we succeeded in taking the reserved lock, unlock it to restore
+      ** the original state */
+      lrc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0);
+    } else {
+      /* if we failed to get the lock then someone else must have it */
+      reserved = 1;
+    }
+    if( IS_LOCK_ERROR(lrc) ){
+      rc=lrc;
+    }
+  }
+
+  sqlite3_mutex_leave(pFile->pInode->pLockMutex);
+  OSTRACE(("TEST WR-LOCK %d %d %d (afp)\n", pFile->h, rc, reserved));
+
+  *pResOut = reserved;
+  return rc;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int afpLock(sqlite3_file *id, int eFileLock){
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode = pFile->pInode;
+  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+
+  assert( pFile );
+  OSTRACE(("LOCK    %d %s was %s(%s,%d) pid=%d (afp)\n", pFile->h,
+           azFileLock(eFileLock), azFileLock(pFile->eFileLock),
+           azFileLock(pInode->eFileLock), pInode->nShared , osGetpid(0)));
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** unixFile, do nothing. Don't use the afp_end_lock: exit path, as
+  ** unixEnterMutex() hasn't been called yet.
+  */
+  if( pFile->eFileLock>=eFileLock ){
+    OSTRACE(("LOCK    %d %s ok (already held) (afp)\n", pFile->h,
+           azFileLock(eFileLock)));
+    return SQLITE_OK;
+  }
+
+  /* Make sure the locking sequence is correct
+  **  (1) We never move from unlocked to anything higher than shared lock.
+  **  (2) SQLite never explicitly requests a pending lock.
+  **  (3) A shared lock is always held when a reserve lock is requested.
+  */
+  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
+  assert( eFileLock!=PENDING_LOCK );
+  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );
+
+  /* This mutex is needed because pFile->pInode is shared across threads
+  */
+  pInode = pFile->pInode;
+  sqlite3_mutex_enter(pInode->pLockMutex);
+
+  /* If some thread using this PID has a lock via a different unixFile*
+  ** handle that precludes the requested lock, return BUSY.
+  */
+  if( (pFile->eFileLock!=pInode->eFileLock &&
+       (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK))
+     ){
+    rc = SQLITE_BUSY;
+    goto afp_end_lock;
+  }
+
+  /* If a SHARED lock is requested, and some thread using this PID already
+  ** has a SHARED or RESERVED lock, then increment reference counts and
+  ** return SQLITE_OK.
+  */
+  if( eFileLock==SHARED_LOCK &&
+     (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){
+    assert( eFileLock==SHARED_LOCK );
+    assert( pFile->eFileLock==0 );
+    assert( pInode->nShared>0 );
+    pFile->eFileLock = SHARED_LOCK;
+    pInode->nShared++;
+    pInode->nLock++;
+    goto afp_end_lock;
+  }
+
+  /* A PENDING lock is needed before acquiring a SHARED lock and before
+  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
+  ** be released.
+  */
+  if( eFileLock==SHARED_LOCK
+      || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK)
+  ){
+    int failed;
+    failed = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 1);
+    if (failed) {
+      rc = failed;
+      goto afp_end_lock;
+    }
+  }
+
+  /* If control gets to this point, then actually go ahead and make
+  ** operating system calls for the specified lock.
+  */
+  if( eFileLock==SHARED_LOCK ){
+    int lrc1, lrc2, lrc1Errno = 0;
+    long lk, mask;
+
+    assert( pInode->nShared==0 );
+    assert( pInode->eFileLock==0 );
+
+    mask = (sizeof(long)==8) ? LARGEST_INT64 : 0x7fffffff;
+    /* Now get the read-lock SHARED_LOCK */
+    /* note that the quality of the randomness doesn't matter that much */
+    lk = random();
+    pInode->sharedByte = (lk & mask)%(SHARED_SIZE - 1);
+    lrc1 = afpSetLock(context->dbPath, pFile,
+          SHARED_FIRST+pInode->sharedByte, 1, 1);
+    if( IS_LOCK_ERROR(lrc1) ){
+      lrc1Errno = pFile->lastErrno;
+    }
+    /* Drop the temporary PENDING lock */
+    lrc2 = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
+
+    if( IS_LOCK_ERROR(lrc1) ) {
+      storeLastErrno(pFile, lrc1Errno);
+      rc = lrc1;
+      goto afp_end_lock;
+    } else if( IS_LOCK_ERROR(lrc2) ){
+      rc = lrc2;
+      goto afp_end_lock;
+    } else if( lrc1 != SQLITE_OK ) {
+      rc = lrc1;
+    } else {
+      pFile->eFileLock = SHARED_LOCK;
+      pInode->nLock++;
+      pInode->nShared = 1;
+    }
+  }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){
+    /* We are trying for an exclusive lock but another thread in this
+     ** same process is still holding a shared lock. */
+    rc = SQLITE_BUSY;
+  }else{
+    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
+    ** assumed that there is a SHARED or greater lock on the file
+    ** already.
+    */
+    int failed = 0;
+    assert( 0!=pFile->eFileLock );
+    if (eFileLock >= RESERVED_LOCK && pFile->eFileLock < RESERVED_LOCK) {
+        /* Acquire a RESERVED lock */
+        failed = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1);
+      if( !failed ){
+        context->reserved = 1;
+      }
+    }
+    if (!failed && eFileLock == EXCLUSIVE_LOCK) {
+      /* Acquire an EXCLUSIVE lock */
+
+      /* Remove the shared lock before trying the range.  we'll need to
+      ** reestablish the shared lock if we can't get the  afpUnlock
+      */
+      if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST +
+                         pInode->sharedByte, 1, 0)) ){
+        int failed2 = SQLITE_OK;
+        /* now attempt to get the exclusive lock range */
+        failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST,
+                               SHARED_SIZE, 1);
+        if( failed && (failed2 = afpSetLock(context->dbPath, pFile,
+                       SHARED_FIRST + pInode->sharedByte, 1, 1)) ){
+          /* Can't reestablish the shared lock.  Sqlite can't deal, this is
+          ** a critical I/O error
+          */
+          rc = ((failed & 0xff) == SQLITE_IOERR) ? failed2 :
+               SQLITE_IOERR_LOCK;
+          goto afp_end_lock;
+        }
+      }else{
+        rc = failed;
+      }
+    }
+    if( failed ){
+      rc = failed;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    pFile->eFileLock = eFileLock;
+    pInode->eFileLock = eFileLock;
+  }else if( eFileLock==EXCLUSIVE_LOCK ){
+    pFile->eFileLock = PENDING_LOCK;
+    pInode->eFileLock = PENDING_LOCK;
+  }
+
+afp_end_lock:
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  OSTRACE(("LOCK    %d %s %s (afp)\n", pFile->h, azFileLock(eFileLock),
+         rc==SQLITE_OK ? "ok" : "failed"));
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int afpUnlock(sqlite3_file *id, int eFileLock) {
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode;
+  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+  int skipShared = 0;
+
+  assert( pFile );
+  OSTRACE(("UNLOCK  %d %d was %d(%d,%d) pid=%d (afp)\n", pFile->h, eFileLock,
+           pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared,
+           osGetpid(0)));
+
+  assert( eFileLock<=SHARED_LOCK );
+  if( pFile->eFileLock<=eFileLock ){
+    return SQLITE_OK;
+  }
+  pInode = pFile->pInode;
+  sqlite3_mutex_enter(pInode->pLockMutex);
+  assert( pInode->nShared!=0 );
+  if( pFile->eFileLock>SHARED_LOCK ){
+    assert( pInode->eFileLock==pFile->eFileLock );
+
+#ifdef SQLITE_DEBUG
+    /* When reducing a lock such that other processes can start
+    ** reading the database file again, make sure that the
+    ** transaction counter was updated if any part of the database
+    ** file changed.  If the transaction counter is not updated,
+    ** other connections to the same file might not realize that
+    ** the file has changed and hence might not know to flush their
+    ** cache.  The use of a stale cache can lead to database corruption.
+    */
+    assert( pFile->inNormalWrite==0
+           || pFile->dbUpdate==0
+           || pFile->transCntrChng==1 );
+    pFile->inNormalWrite = 0;
+#endif
+
+    if( pFile->eFileLock==EXCLUSIVE_LOCK ){
+      rc = afpSetLock(context->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0);
+      if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1) ){
+        /* only re-establish the shared lock if necessary */
+        int sharedLockByte = SHARED_FIRST+pInode->sharedByte;
+        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 1);
+      } else {
+        skipShared = 1;
+      }
+    }
+    if( rc==SQLITE_OK && pFile->eFileLock>=PENDING_LOCK ){
+      rc = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
+    }
+    if( rc==SQLITE_OK && pFile->eFileLock>=RESERVED_LOCK && context->reserved ){
+      rc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0);
+      if( !rc ){
+        context->reserved = 0;
+      }
+    }
+    if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1)){
+      pInode->eFileLock = SHARED_LOCK;
+    }
+  }
+  if( rc==SQLITE_OK && eFileLock==NO_LOCK ){
+
+    /* Decrement the shared lock counter.  Release the lock using an
+    ** OS call only when all threads in this same process have released
+    ** the lock.
+    */
+    unsigned long long sharedLockByte = SHARED_FIRST+pInode->sharedByte;
+    pInode->nShared--;
+    if( pInode->nShared==0 ){
+      if( !skipShared ){
+        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 0);
+      }
+      if( !rc ){
+        pInode->eFileLock = NO_LOCK;
+        pFile->eFileLock = NO_LOCK;
+      }
+    }
+    if( rc==SQLITE_OK ){
+      pInode->nLock--;
+      assert( pInode->nLock>=0 );
+      if( pInode->nLock==0 ) closePendingFds(pFile);
+    }
+  }
+
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  if( rc==SQLITE_OK ){
+    pFile->eFileLock = eFileLock;
+  }
+  return rc;
+}
+
+/*
+** Close a file & cleanup AFP specific locking context
+*/
+static int afpClose(sqlite3_file *id) {
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  assert( id!=0 );
+  afpUnlock(id, NO_LOCK);
+  assert( unixFileMutexNotheld(pFile) );
+  unixEnterMutex();
+  if( pFile->pInode ){
+    unixInodeInfo *pInode = pFile->pInode;
+    sqlite3_mutex_enter(pInode->pLockMutex);
+    if( pInode->nLock ){
+      /* If there are outstanding locks, do not actually close the file just
+      ** yet because that would clear those locks.  Instead, add the file
+      ** descriptor to pInode->aPending.  It will be automatically closed when
+      ** the last lock is cleared.
+      */
+      setPendingFd(pFile);
+    }
+    sqlite3_mutex_leave(pInode->pLockMutex);
+  }
+  releaseInodeInfo(pFile);
+  sqlite3_free(pFile->lockingContext);
+  rc = closeUnixFile(id);
+  unixLeaveMutex();
+  return rc;
+}
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+/*
+** The code above is the AFP lock implementation.  The code is specific
+** to MacOSX and does not work on other unix platforms.  No alternative
+** is available.  If you don't compile for a mac, then the "unix-afp"
+** VFS is not available.
+**
+********************* End of the AFP lock implementation **********************
+******************************************************************************/
+
+/******************************************************************************
+*************************** Begin NFS Locking ********************************/
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+/*
+ ** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+ ** must be either NO_LOCK or SHARED_LOCK.
+ **
+ ** If the locking level of the file descriptor is already at or below
+ ** the requested locking level, this routine is a no-op.
+ */
+static int nfsUnlock(sqlite3_file *id, int eFileLock){
+  return posixUnlock(id, eFileLock, 1);
+}
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+/*
+** The code above is the NFS lock implementation.  The code is specific
+** to MacOSX and does not work on other unix platforms.  No alternative
+** is available.
+**
+********************* End of the NFS lock implementation **********************
+******************************************************************************/
+
+/******************************************************************************
+**************** Non-locking sqlite3_file methods *****************************
+**
+** The next division contains implementations for all methods of the
+** sqlite3_file object other than the locking methods.  The locking
+** methods were defined in divisions above (one locking method per
+** division).  Those methods that are common to all locking modes
+** are gather together into this division.
+*/
+
+/*
+** Seek to the offset passed as the second argument, then read cnt
+** bytes into pBuf. Return the number of bytes actually read.
+**
+** To avoid stomping the errno value on a failed read the lastErrno value
+** is set before returning.
+*/
+static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
+  int got;
+  int prior = 0;
+#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
+  i64 newOffset;
+#endif
+  TIMER_START;
+  assert( cnt==(cnt&0x1ffff) );
+  assert( id->h>2 );
+  do{
+#if defined(USE_PREAD)
+    got = osPread(id->h, pBuf, cnt, offset);
+    SimulateIOError( got = -1 );
+#elif defined(USE_PREAD64)
+    got = osPread64(id->h, pBuf, cnt, offset);
+    SimulateIOError( got = -1 );
+#else
+    newOffset = lseek(id->h, offset, SEEK_SET);
+    SimulateIOError( newOffset = -1 );
+    if( newOffset<0 ){
+      storeLastErrno((unixFile*)id, errno);
+      return -1;
+    }
+    got = osRead(id->h, pBuf, cnt);
+#endif
+    if( got==cnt ) break;
+    if( got<0 ){
+      if( errno==EINTR ){ got = 1; continue; }
+      prior = 0;
+      storeLastErrno((unixFile*)id,  errno);
+      break;
+    }else if( got>0 ){
+      cnt -= got;
+      offset += got;
+      prior += got;
+      pBuf = (void*)(got + (char*)pBuf);
+    }
+  }while( got>0 );
+  TIMER_END;
+  OSTRACE(("READ    %-3d %5d %7lld %llu\n",
+            id->h, got+prior, offset-prior, TIMER_ELAPSED));
+  return got+prior;
+}
+
+/*
+** Read data from a file into a buffer.  Return SQLITE_OK if all
+** bytes were read successfully and SQLITE_IOERR if anything goes
+** wrong.
+*/
+static int unixRead(
+  sqlite3_file *id,
+  void *pBuf,
+  int amt,
+  sqlite3_int64 offset
+){
+  unixFile *pFile = (unixFile *)id;
+  int got;
+  assert( id );
+  assert( offset>=0 );
+  assert( amt>0 );
+
+  /* If this is a database file (not a journal, super-journal or temp
+  ** file), the bytes in the locking range should never be read or written. */
+#if 0
+  assert( pFile->pPreallocatedUnused==0
+       || offset>=PENDING_BYTE+512
+       || offset+amt<=PENDING_BYTE
+  );
+#endif
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  /* Deal with as much of this read request as possible by transferring
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt);
+      return SQLITE_OK;
+    }else{
+      int nCopy = pFile->mmapSize - offset;
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+#endif
+
+  got = seekAndRead(pFile, offset, pBuf, amt);
+  if( got==amt ){
+    return SQLITE_OK;
+  }else if( got<0 ){
+    /* pFile->lastErrno has been set by seekAndRead().
+    ** Usually we return SQLITE_IOERR_READ here, though for some
+    ** kinds of errors we return SQLITE_IOERR_CORRUPTFS.  The
+    ** SQLITE_IOERR_CORRUPTFS will be converted into SQLITE_CORRUPT
+    ** prior to returning to the application by the sqlite3ApiExit()
+    ** routine.
+    */
+    switch( pFile->lastErrno ){
+      case ERANGE:
+      case EIO:
+#ifdef ENXIO
+      case ENXIO:
+#endif
+#ifdef EDEVERR
+      case EDEVERR:
+#endif
+        return SQLITE_IOERR_CORRUPTFS;
+    }
+    return SQLITE_IOERR_READ;
+  }else{
+    storeLastErrno(pFile, 0);   /* not a system error */
+    /* Unread parts of the buffer must be zero-filled */
+    memset(&((char*)pBuf)[got], 0, amt-got);
+    return SQLITE_IOERR_SHORT_READ;
+  }
+}
+
+/*
+** Attempt to seek the file-descriptor passed as the first argument to
+** absolute offset iOff, then attempt to write nBuf bytes of data from
+** pBuf to it. If an error occurs, return -1 and set *piErrno. Otherwise,
+** return the actual number of bytes written (which may be less than
+** nBuf).
+*/
+static int seekAndWriteFd(
+  int fd,                         /* File descriptor to write to */
+  i64 iOff,                       /* File offset to begin writing at */
+  const void *pBuf,               /* Copy data from this buffer to the file */
+  int nBuf,                       /* Size of buffer pBuf in bytes */
+  int *piErrno                    /* OUT: Error number if error occurs */
+){
+  int rc = 0;                     /* Value returned by system call */
+
+  assert( nBuf==(nBuf&0x1ffff) );
+  assert( fd>2 );
+  assert( piErrno!=0 );
+  nBuf &= 0x1ffff;
+  TIMER_START;
+
+#if defined(USE_PREAD)
+  do{ rc = (int)osPwrite(fd, pBuf, nBuf, iOff); }while( rc<0 && errno==EINTR );
+#elif defined(USE_PREAD64)
+  do{ rc = (int)osPwrite64(fd, pBuf, nBuf, iOff);}while( rc<0 && errno==EINTR);
+#else
+  do{
+    i64 iSeek = lseek(fd, iOff, SEEK_SET);
+    SimulateIOError( iSeek = -1 );
+    if( iSeek<0 ){
+      rc = -1;
+      break;
+    }
+    rc = osWrite(fd, pBuf, nBuf);
+  }while( rc<0 && errno==EINTR );
+#endif
+
+  TIMER_END;
+  OSTRACE(("WRITE   %-3d %5d %7lld %llu\n", fd, rc, iOff, TIMER_ELAPSED));
+
+  if( rc<0 ) *piErrno = errno;
+  return rc;
+}
+
+
+/*
+** Seek to the offset in id->offset then read cnt bytes into pBuf.
+** Return the number of bytes actually read.  Update the offset.
+**
+** To avoid stomping the errno value on a failed write the lastErrno value
+** is set before returning.
+*/
+static int seekAndWrite(unixFile *id, i64 offset, const void *pBuf, int cnt){
+  return seekAndWriteFd(id->h, offset, pBuf, cnt, &id->lastErrno);
+}
+
+
+/*
+** Write data from a buffer into a file.  Return SQLITE_OK on success
+** or some other error code on failure.
+*/
+static int unixWrite(
+  sqlite3_file *id,
+  const void *pBuf,
+  int amt,
+  sqlite3_int64 offset
+){
+  unixFile *pFile = (unixFile*)id;
+  int wrote = 0;
+  assert( id );
+  assert( amt>0 );
+
+  /* If this is a database file (not a journal, super-journal or temp
+  ** file), the bytes in the locking range should never be read or written. */
+#if 0
+  assert( pFile->pPreallocatedUnused==0
+       || offset>=PENDING_BYTE+512
+       || offset+amt<=PENDING_BYTE
+  );
+#endif
+
+#ifdef SQLITE_DEBUG
+  /* If we are doing a normal write to a database file (as opposed to
+  ** doing a hot-journal rollback or a write to some file other than a
+  ** normal database file) then record the fact that the database
+  ** has changed.  If the transaction counter is modified, record that
+  ** fact too.
+  */
+  if( pFile->inNormalWrite ){
+    pFile->dbUpdate = 1;  /* The database has been modified */
+    if( offset<=24 && offset+amt>=27 ){
+      int rc;
+      char oldCntr[4];
+      SimulateIOErrorBenign(1);
+      rc = seekAndRead(pFile, 24, oldCntr, 4);
+      SimulateIOErrorBenign(0);
+      if( rc!=4 || memcmp(oldCntr, &((char*)pBuf)[24-offset], 4)!=0 ){
+        pFile->transCntrChng = 1;  /* The transaction counter has changed */
+      }
+    }
+  }
+#endif
+
+#if defined(SQLITE_MMAP_READWRITE) && SQLITE_MAX_MMAP_SIZE>0
+  /* Deal with as much of this write request as possible by transferring
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt);
+      return SQLITE_OK;
+    }else{
+      int nCopy = pFile->mmapSize - offset;
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+#endif
+
+  while( (wrote = seekAndWrite(pFile, offset, pBuf, amt))<amt && wrote>0 ){
+    amt -= wrote;
+    offset += wrote;
+    pBuf = &((char*)pBuf)[wrote];
+  }
+  SimulateIOError(( wrote=(-1), amt=1 ));
+  SimulateDiskfullError(( wrote=0, amt=1 ));
+
+  if( amt>wrote ){
+    if( wrote<0 && pFile->lastErrno!=ENOSPC ){
+      /* lastErrno set by seekAndWrite */
+      return SQLITE_IOERR_WRITE;
+    }else{
+      storeLastErrno(pFile, 0); /* not a system error */
+      return SQLITE_FULL;
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Count the number of fullsyncs and normal syncs.  This is used to test
+** that syncs and fullsyncs are occurring at the right times.
+*/
+SQLITE_API int sqlite3_sync_count = 0;
+SQLITE_API int sqlite3_fullsync_count = 0;
+#endif
+
+/*
+** We do not trust systems to provide a working fdatasync().  Some do.
+** Others do no.  To be safe, we will stick with the (slightly slower)
+** fsync(). If you know that your system does support fdatasync() correctly,
+** then simply compile with -Dfdatasync=fdatasync or -DHAVE_FDATASYNC
+*/
+#if !defined(fdatasync) && !HAVE_FDATASYNC
+# define fdatasync fsync
+#endif
+
+/*
+** Define HAVE_FULLFSYNC to 0 or 1 depending on whether or not
+** the F_FULLFSYNC macro is defined.  F_FULLFSYNC is currently
+** only available on Mac OS X.  But that could change.
+*/
+#ifdef F_FULLFSYNC
+# define HAVE_FULLFSYNC 1
+#else
+# define HAVE_FULLFSYNC 0
+#endif
+
+
+/*
+** The fsync() system call does not work as advertised on many
+** unix systems.  The following procedure is an attempt to make
+** it work better.
+**
+** The SQLITE_NO_SYNC macro disables all fsync()s.  This is useful
+** for testing when we want to run through the test suite quickly.
+** You are strongly advised *not* to deploy with SQLITE_NO_SYNC
+** enabled, however, since with SQLITE_NO_SYNC enabled, an OS crash
+** or power failure will likely corrupt the database file.
+**
+** SQLite sets the dataOnly flag if the size of the file is unchanged.
+** The idea behind dataOnly is that it should only write the file content
+** to disk, not the inode.  We only set dataOnly if the file size is
+** unchanged since the file size is part of the inode.  However,
+** Ted Ts'o tells us that fdatasync() will also write the inode if the
+** file size has changed.  The only real difference between fdatasync()
+** and fsync(), Ted tells us, is that fdatasync() will not flush the
+** inode if the mtime or owner or other inode attributes have changed.
+** We only care about the file size, not the other file attributes, so
+** as far as SQLite is concerned, an fdatasync() is always adequate.
+** So, we always use fdatasync() if it is available, regardless of
+** the value of the dataOnly flag.
+*/
+static int full_fsync(int fd, int fullSync, int dataOnly){
+  int rc;
+
+  /* The following "ifdef/elif/else/" block has the same structure as
+  ** the one below. It is replicated here solely to avoid cluttering
+  ** up the real code with the UNUSED_PARAMETER() macros.
+  */
+#ifdef SQLITE_NO_SYNC
+  UNUSED_PARAMETER(fd);
+  UNUSED_PARAMETER(fullSync);
+  UNUSED_PARAMETER(dataOnly);
+#elif HAVE_FULLFSYNC
+  UNUSED_PARAMETER(dataOnly);
+#else
+  UNUSED_PARAMETER(fullSync);
+  UNUSED_PARAMETER(dataOnly);
+#endif
+
+  /* Record the number of times that we do a normal fsync() and
+  ** FULLSYNC.  This is used during testing to verify that this procedure
+  ** gets called with the correct arguments.
+  */
+#ifdef SQLITE_TEST
+  if( fullSync ) sqlite3_fullsync_count++;
+  sqlite3_sync_count++;
+#endif
+
+  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
+  ** no-op.  But go ahead and call fstat() to validate the file
+  ** descriptor as we need a method to provoke a failure during
+  ** coverage testing.
+  */
+#ifdef SQLITE_NO_SYNC
+  {
+    struct stat buf;
+    rc = osFstat(fd, &buf);
+  }
+#elif HAVE_FULLFSYNC
+  if( fullSync ){
+    rc = osFcntl(fd, F_FULLFSYNC, 0);
+  }else{
+    rc = 1;
+  }
+  /* If the FULLFSYNC failed, fall back to attempting an fsync().
+  ** It shouldn't be possible for fullfsync to fail on the local
+  ** file system (on OSX), so failure indicates that FULLFSYNC
+  ** isn't supported for this file system. So, attempt an fsync
+  ** and (for now) ignore the overhead of a superfluous fcntl call.
+  ** It'd be better to detect fullfsync support once and avoid
+  ** the fcntl call every time sync is called.
+  */
+  if( rc ) rc = fsync(fd);
+
+#elif defined(__APPLE__)
+  /* fdatasync() on HFS+ doesn't yet flush the file size if it changed correctly
+  ** so currently we default to the macro that redefines fdatasync to fsync
+  */
+  rc = fsync(fd);
+#else
+  rc = fdatasync(fd);
+#if OS_VXWORKS
+  if( rc==-1 && errno==ENOTSUP ){
+    rc = fsync(fd);
+  }
+#endif /* OS_VXWORKS */
+#endif /* ifdef SQLITE_NO_SYNC elif HAVE_FULLFSYNC */
+
+  if( OS_VXWORKS && rc!= -1 ){
+    rc = 0;
+  }
+  return rc;
+}
+
+/*
+** Open a file descriptor to the directory containing file zFilename.
+** If successful, *pFd is set to the opened file descriptor and
+** SQLITE_OK is returned. If an error occurs, either SQLITE_NOMEM
+** or SQLITE_CANTOPEN is returned and *pFd is set to an undefined
+** value.
+**
+** The directory file descriptor is used for only one thing - to
+** fsync() a directory to make sure file creation and deletion events
+** are flushed to disk.  Such fsyncs are not needed on newer
+** journaling filesystems, but are required on older filesystems.
+**
+** This routine can be overridden using the xSetSysCall interface.
+** The ability to override this routine was added in support of the
+** chromium sandbox.  Opening a directory is a security risk (we are
+** told) so making it overrideable allows the chromium sandbox to
+** replace this routine with a harmless no-op.  To make this routine
+** a no-op, replace it with a stub that returns SQLITE_OK but leaves
+** *pFd set to a negative number.
+**
+** If SQLITE_OK is returned, the caller is responsible for closing
+** the file descriptor *pFd using close().
+*/
+static int openDirectory(const char *zFilename, int *pFd){
+  int ii;
+  int fd = -1;
+  char zDirname[MAX_PATHNAME+1];
+
+  sqlite3_snprintf(MAX_PATHNAME, zDirname, "%s", zFilename);
+  for(ii=(int)strlen(zDirname); ii>0 && zDirname[ii]!='/'; ii--);
+  if( ii>0 ){
+    zDirname[ii] = '\0';
+  }else{
+    if( zDirname[0]!='/' ) zDirname[0] = '.';
+    zDirname[1] = 0;
+  }
+  fd = robust_open(zDirname, O_RDONLY|O_BINARY, 0);
+  if( fd>=0 ){
+    OSTRACE(("OPENDIR %-3d %s\n", fd, zDirname));
+  }
+  *pFd = fd;
+  if( fd>=0 ) return SQLITE_OK;
+  return unixLogError(SQLITE_CANTOPEN_BKPT, "openDirectory", zDirname);
+}
+
+/*
+** Make sure all writes to a particular file are committed to disk.
+**
+** If dataOnly==0 then both the file itself and its metadata (file
+** size, access time, etc) are synced.  If dataOnly!=0 then only the
+** file data is synced.
+**
+** Under Unix, also make sure that the directory entry for the file
+** has been created by fsync-ing the directory that contains the file.
+** If we do not do this and we encounter a power failure, the directory
+** entry for the journal might not exist after we reboot.  The next
+** SQLite to access the file will not know that the journal exists (because
+** the directory entry for the journal was never created) and the transaction
+** will not roll back - possibly leading to database corruption.
+*/
+static int unixSync(sqlite3_file *id, int flags){
+  int rc;
+  unixFile *pFile = (unixFile*)id;
+
+  int isDataOnly = (flags&SQLITE_SYNC_DATAONLY);
+  int isFullsync = (flags&0x0F)==SQLITE_SYNC_FULL;
+
+  /* Check that one of SQLITE_SYNC_NORMAL or FULL was passed */
+  assert((flags&0x0F)==SQLITE_SYNC_NORMAL
+      || (flags&0x0F)==SQLITE_SYNC_FULL
+  );
+
+  /* Unix cannot, but some systems may return SQLITE_FULL from here. This
+  ** line is to test that doing so does not cause any problems.
+  */
+  SimulateDiskfullError( return SQLITE_FULL );
+
+  assert( pFile );
+  OSTRACE(("SYNC    %-3d\n", pFile->h));
+  rc = full_fsync(pFile->h, isFullsync, isDataOnly);
+  SimulateIOError( rc=1 );
+  if( rc ){
+    storeLastErrno(pFile, errno);
+    return unixLogError(SQLITE_IOERR_FSYNC, "full_fsync", pFile->zPath);
+  }
+
+  /* Also fsync the directory containing the file if the DIRSYNC flag
+  ** is set.  This is a one-time occurrence.  Many systems (examples: AIX)
+  ** are unable to fsync a directory, so ignore errors on the fsync.
+  */
+  if( pFile->ctrlFlags & UNIXFILE_DIRSYNC ){
+    int dirfd;
+    OSTRACE(("DIRSYNC %s (have_fullfsync=%d fullsync=%d)\n", pFile->zPath,
+            HAVE_FULLFSYNC, isFullsync));
+    rc = osOpenDirectory(pFile->zPath, &dirfd);
+    if( rc==SQLITE_OK ){
+      full_fsync(dirfd, 0, 0);
+      robust_close(pFile, dirfd, __LINE__);
+    }else{
+      assert( rc==SQLITE_CANTOPEN );
+      rc = SQLITE_OK;
+    }
+    pFile->ctrlFlags &= ~UNIXFILE_DIRSYNC;
+  }
+  return rc;
+}
+
+/*
+** Truncate an open file to a specified size
+*/
+static int unixTruncate(sqlite3_file *id, i64 nByte){
+  unixFile *pFile = (unixFile *)id;
+  int rc;
+  assert( pFile );
+  SimulateIOError( return SQLITE_IOERR_TRUNCATE );
+
+  /* If the user has configured a chunk-size for this file, truncate the
+  ** file so that it consists of an integer number of chunks (i.e. the
+  ** actual file size after the operation may be larger than the requested
+  ** size).
+  */
+  if( pFile->szChunk>0 ){
+    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
+  }
+
+  rc = robust_ftruncate(pFile->h, nByte);
+  if( rc ){
+    storeLastErrno(pFile, errno);
+    return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath);
+  }else{
+#ifdef SQLITE_DEBUG
+    /* If we are doing a normal write to a database file (as opposed to
+    ** doing a hot-journal rollback or a write to some file other than a
+    ** normal database file) and we truncate the file to zero length,
+    ** that effectively updates the change counter.  This might happen
+    ** when restoring a database using the backup API from a zero-length
+    ** source.
+    */
+    if( pFile->inNormalWrite && nByte==0 ){
+      pFile->transCntrChng = 1;
+    }
+#endif
+
+#if SQLITE_MAX_MMAP_SIZE>0
+    /* If the file was just truncated to a size smaller than the currently
+    ** mapped region, reduce the effective mapping size as well. SQLite will
+    ** use read() and write() to access data beyond this point from now on.
+    */
+    if( nByte<pFile->mmapSize ){
+      pFile->mmapSize = nByte;
+    }
+#endif
+
+    return SQLITE_OK;
+  }
+}
+
+/*
+** Determine the current size of a file in bytes
+*/
+static int unixFileSize(sqlite3_file *id, i64 *pSize){
+  int rc;
+  struct stat buf;
+  assert( id );
+  rc = osFstat(((unixFile*)id)->h, &buf);
+  SimulateIOError( rc=1 );
+  if( rc!=0 ){
+    storeLastErrno((unixFile*)id, errno);
+    return SQLITE_IOERR_FSTAT;
+  }
+  *pSize = buf.st_size;
+
+  /* When opening a zero-size database, the findInodeInfo() procedure
+  ** writes a single byte into that file in order to work around a bug
+  ** in the OS-X msdos filesystem.  In order to avoid problems with upper
+  ** layers, we need to report this file size as zero even though it is
+  ** really 1.   Ticket #3260.
+  */
+  if( *pSize==1 ) *pSize = 0;
+
+
+  return SQLITE_OK;
+}
+
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+/*
+** Handler for proxy-locking file-control verbs.  Defined below in the
+** proxying locking division.
+*/
+static int proxyFileControl(sqlite3_file*,int,void*);
+#endif
+
+/*
+** This function is called to handle the SQLITE_FCNTL_SIZE_HINT
+** file-control operation.  Enlarge the database to nBytes in size
+** (rounded up to the next chunk-size).  If the database is already
+** nBytes or larger, this routine is a no-op.
+*/
+static int fcntlSizeHint(unixFile *pFile, i64 nByte){
+  if( pFile->szChunk>0 ){
+    i64 nSize;                    /* Required file size */
+    struct stat buf;              /* Used to hold return values of fstat() */
+
+    if( osFstat(pFile->h, &buf) ){
+      return SQLITE_IOERR_FSTAT;
+    }
+
+    nSize = ((nByte+pFile->szChunk-1) / pFile->szChunk) * pFile->szChunk;
+    if( nSize>(i64)buf.st_size ){
+
+#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE
+      /* The code below is handling the return value of osFallocate()
+      ** correctly. posix_fallocate() is defined to "returns zero on success,
+      ** or an error number on  failure". See the manpage for details. */
+      int err;
+      do{
+        err = osFallocate(pFile->h, buf.st_size, nSize-buf.st_size);
+      }while( err==EINTR );
+      if( err && err!=EINVAL ) return SQLITE_IOERR_WRITE;
+#else
+      /* If the OS does not have posix_fallocate(), fake it. Write a
+      ** single byte to the last byte in each block that falls entirely
+      ** within the extended region. Then, if required, a single byte
+      ** at offset (nSize-1), to set the size of the file correctly.
+      ** This is a similar technique to that used by glibc on systems
+      ** that do not have a real fallocate() call.
+      */
+      int nBlk = buf.st_blksize;  /* File-system block size */
+      int nWrite = 0;             /* Number of bytes written by seekAndWrite */
+      i64 iWrite;                 /* Next offset to write to */
+
+      iWrite = (buf.st_size/nBlk)*nBlk + nBlk - 1;
+      assert( iWrite>=buf.st_size );
+      assert( ((iWrite+1)%nBlk)==0 );
+      for(/*no-op*/; iWrite<nSize+nBlk-1; iWrite+=nBlk ){
+        if( iWrite>=nSize ) iWrite = nSize - 1;
+        nWrite = seekAndWrite(pFile, iWrite, "", 1);
+        if( nWrite!=1 ) return SQLITE_IOERR_WRITE;
+      }
+#endif
+    }
+  }
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFile->mmapSizeMax>0 && nByte>pFile->mmapSize ){
+    int rc;
+    if( pFile->szChunk<=0 ){
+      if( robust_ftruncate(pFile->h, nByte) ){
+        storeLastErrno(pFile, errno);
+        return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath);
+      }
+    }
+
+    rc = unixMapfile(pFile, nByte);
+    return rc;
+  }
+#endif
+
+  return SQLITE_OK;
+}
+
+/*
+** If *pArg is initially negative then this is a query.  Set *pArg to
+** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
+**
+** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
+*/
+static void unixModeBit(unixFile *pFile, unsigned char mask, int *pArg){
+  if( *pArg<0 ){
+    *pArg = (pFile->ctrlFlags & mask)!=0;
+  }else if( (*pArg)==0 ){
+    pFile->ctrlFlags &= ~mask;
+  }else{
+    pFile->ctrlFlags |= mask;
+  }
+}
+
+/* Forward declaration */
+static int unixGetTempname(int nBuf, char *zBuf);
+#if !defined(SQLITE_WASI) && !defined(SQLITE_OMIT_WAL)
+ static int unixFcntlExternalReader(unixFile*, int*);
+#endif
+
+/*
+** Information and control of an open file handle.
+*/
+static int unixFileControl(sqlite3_file *id, int op, void *pArg){
+  unixFile *pFile = (unixFile*)id;
+  switch( op ){
+#if defined(__linux__) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+    case SQLITE_FCNTL_BEGIN_ATOMIC_WRITE: {
+      int rc = osIoctl(pFile->h, F2FS_IOC_START_ATOMIC_WRITE);
+      return rc ? SQLITE_IOERR_BEGIN_ATOMIC : SQLITE_OK;
+    }
+    case SQLITE_FCNTL_COMMIT_ATOMIC_WRITE: {
+      int rc = osIoctl(pFile->h, F2FS_IOC_COMMIT_ATOMIC_WRITE);
+      return rc ? SQLITE_IOERR_COMMIT_ATOMIC : SQLITE_OK;
+    }
+    case SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE: {
+      int rc = osIoctl(pFile->h, F2FS_IOC_ABORT_VOLATILE_WRITE);
+      return rc ? SQLITE_IOERR_ROLLBACK_ATOMIC : SQLITE_OK;
+    }
+#endif /* __linux__ && SQLITE_ENABLE_BATCH_ATOMIC_WRITE */
+
+    case SQLITE_FCNTL_NULL_IO: {
+      osClose(pFile->h);
+      pFile->h = -1;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_LOCKSTATE: {
+      *(int*)pArg = pFile->eFileLock;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_LAST_ERRNO: {
+      *(int*)pArg = pFile->lastErrno;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_CHUNK_SIZE: {
+      pFile->szChunk = *(int *)pArg;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_SIZE_HINT: {
+      int rc;
+      SimulateIOErrorBenign(1);
+      rc = fcntlSizeHint(pFile, *(i64 *)pArg);
+      SimulateIOErrorBenign(0);
+      return rc;
+    }
+    case SQLITE_FCNTL_PERSIST_WAL: {
+      unixModeBit(pFile, UNIXFILE_PERSIST_WAL, (int*)pArg);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
+      unixModeBit(pFile, UNIXFILE_PSOW, (int*)pArg);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_VFSNAME: {
+      *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_TEMPFILENAME: {
+      char *zTFile = sqlite3_malloc64( pFile->pVfs->mxPathname );
+      if( zTFile ){
+        unixGetTempname(pFile->pVfs->mxPathname, zTFile);
+        *(char**)pArg = zTFile;
+      }
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_HAS_MOVED: {
+      *(int*)pArg = fileHasMoved(pFile);
+      return SQLITE_OK;
+    }
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    case SQLITE_FCNTL_LOCK_TIMEOUT: {
+      int iOld = pFile->iBusyTimeout;
+#if SQLITE_ENABLE_SETLK_TIMEOUT==1
+      pFile->iBusyTimeout = *(int*)pArg;
+#elif SQLITE_ENABLE_SETLK_TIMEOUT==2
+      pFile->iBusyTimeout = !!(*(int*)pArg);
+#else
+# error "SQLITE_ENABLE_SETLK_TIMEOUT must be set to 1 or 2"
+#endif
+      *(int*)pArg = iOld;
+      return SQLITE_OK;
+    }
+#endif
+#if SQLITE_MAX_MMAP_SIZE>0
+    case SQLITE_FCNTL_MMAP_SIZE: {
+      i64 newLimit = *(i64*)pArg;
+      int rc = SQLITE_OK;
+      if( newLimit>sqlite3GlobalConfig.mxMmap ){
+        newLimit = sqlite3GlobalConfig.mxMmap;
+      }
+
+      /* The value of newLimit may be eventually cast to (size_t) and passed
+      ** to mmap(). Restrict its value to 2GB if (size_t) is not at least a
+      ** 64-bit type. */
+      if( newLimit>0 && sizeof(size_t)<8 ){
+        newLimit = (newLimit & 0x7FFFFFFF);
+      }
+
+      *(i64*)pArg = pFile->mmapSizeMax;
+      if( newLimit>=0 && newLimit!=pFile->mmapSizeMax && pFile->nFetchOut==0 ){
+        pFile->mmapSizeMax = newLimit;
+        if( pFile->mmapSize>0 ){
+          unixUnmapfile(pFile);
+          rc = unixMapfile(pFile, -1);
+        }
+      }
+      return rc;
+    }
+#endif
+#ifdef SQLITE_DEBUG
+    /* The pager calls this method to signal that it has done
+    ** a rollback and that the database is therefore unchanged and
+    ** it hence it is OK for the transaction change counter to be
+    ** unchanged.
+    */
+    case SQLITE_FCNTL_DB_UNCHANGED: {
+      ((unixFile*)id)->dbUpdate = 0;
+      return SQLITE_OK;
+    }
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+    case SQLITE_FCNTL_SET_LOCKPROXYFILE:
+    case SQLITE_FCNTL_GET_LOCKPROXYFILE: {
+      return proxyFileControl(id,op,pArg);
+    }
+#endif /* SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) */
+
+    case SQLITE_FCNTL_EXTERNAL_READER: {
+#if !defined(SQLITE_WASI) && !defined(SQLITE_OMIT_WAL)
+      return unixFcntlExternalReader((unixFile*)id, (int*)pArg);
+#else
+      *(int*)pArg = 0;
+      return SQLITE_OK;
+#endif
+    }
+  }
+  return SQLITE_NOTFOUND;
+}
+
+/*
+** If pFd->sectorSize is non-zero when this function is called, it is a
+** no-op. Otherwise, the values of pFd->sectorSize and
+** pFd->deviceCharacteristics are set according to the file-system
+** characteristics.
+**
+** There are two versions of this function. One for QNX and one for all
+** other systems.
+*/
+#ifndef __QNXNTO__
+static void setDeviceCharacteristics(unixFile *pFd){
+  assert( pFd->deviceCharacteristics==0 || pFd->sectorSize!=0 );
+  if( pFd->sectorSize==0 ){
+#if defined(__linux__) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+    int res;
+    u32 f = 0;
+
+    /* Check for support for F2FS atomic batch writes. */
+    res = osIoctl(pFd->h, F2FS_IOC_GET_FEATURES, &f);
+    if( res==0 && (f & F2FS_FEATURE_ATOMIC_WRITE) ){
+      pFd->deviceCharacteristics = SQLITE_IOCAP_BATCH_ATOMIC;
+    }
+#endif /* __linux__ && SQLITE_ENABLE_BATCH_ATOMIC_WRITE */
+
+    /* Set the POWERSAFE_OVERWRITE flag if requested. */
+    if( pFd->ctrlFlags & UNIXFILE_PSOW ){
+      pFd->deviceCharacteristics |= SQLITE_IOCAP_POWERSAFE_OVERWRITE;
+    }
+    pFd->deviceCharacteristics |= SQLITE_IOCAP_SUBPAGE_READ;
+
+    pFd->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE;
+  }
+}
+#else
+#include <sys/dcmd_blk.h>
+#include <sys/statvfs.h>
+static void setDeviceCharacteristics(unixFile *pFile){
+  if( pFile->sectorSize == 0 ){
+    struct statvfs fsInfo;
+
+    /* Set defaults for non-supported filesystems */
+    pFile->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE;
+    pFile->deviceCharacteristics = 0;
+    if( fstatvfs(pFile->h, &fsInfo) == -1 ) {
+      return;
+    }
+
+    if( !strcmp(fsInfo.f_basetype, "tmp") ) {
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        SQLITE_IOCAP_ATOMIC4K |       /* All ram filesystem writes are atomic */
+        SQLITE_IOCAP_SAFE_APPEND |    /* growing the file does not occur until
+                                      ** the write succeeds */
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else if( strstr(fsInfo.f_basetype, "etfs") ){
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        /* etfs cluster size writes are atomic */
+        (pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) |
+        SQLITE_IOCAP_SAFE_APPEND |    /* growing the file does not occur until
+                                      ** the write succeeds */
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else if( !strcmp(fsInfo.f_basetype, "qnx6") ){
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        SQLITE_IOCAP_ATOMIC |         /* All filesystem writes are atomic */
+        SQLITE_IOCAP_SAFE_APPEND |    /* growing the file does not occur until
+                                      ** the write succeeds */
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else if( !strcmp(fsInfo.f_basetype, "qnx4") ){
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        /* full bitset of atomics from max sector size and smaller */
+        (((pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) << 1) - 2) |
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else if( strstr(fsInfo.f_basetype, "dos") ){
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        /* full bitset of atomics from max sector size and smaller */
+        (((pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) << 1) - 2) |
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else{
+      pFile->deviceCharacteristics =
+        SQLITE_IOCAP_ATOMIC512 |      /* blocks are atomic */
+        SQLITE_IOCAP_SAFE_APPEND |    /* growing the file does not occur until
+                                      ** the write succeeds */
+        0;
+    }
+  }
+  /* Last chance verification.  If the sector size isn't a multiple of 512
+  ** then it isn't valid.*/
+  if( pFile->sectorSize % 512 != 0 ){
+    pFile->deviceCharacteristics = 0;
+    pFile->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE;
+  }
+}
+#endif
+
+/*
+** Return the sector size in bytes of the underlying block device for
+** the specified file. This is almost always 512 bytes, but may be
+** larger for some devices.
+**
+** SQLite code assumes this function cannot fail. It also assumes that
+** if two files are created in the same file-system directory (i.e.
+** a database and its journal file) that the sector size will be the
+** same for both.
+*/
+static int unixSectorSize(sqlite3_file *id){
+  unixFile *pFd = (unixFile*)id;
+  setDeviceCharacteristics(pFd);
+  return pFd->sectorSize;
+}
+
+/*
+** Return the device characteristics for the file.
+**
+** This VFS is set up to return SQLITE_IOCAP_POWERSAFE_OVERWRITE by default.
+** However, that choice is controversial since technically the underlying
+** file system does not always provide powersafe overwrites.  (In other
+** words, after a power-loss event, parts of the file that were never
+** written might end up being altered.)  However, non-PSOW behavior is very,
+** very rare.  And asserting PSOW makes a large reduction in the amount
+** of required I/O for journaling, since a lot of padding is eliminated.
+**  Hence, while POWERSAFE_OVERWRITE is on by default, there is a file-control
+** available to turn it off and URI query parameter available to turn it off.
+*/
+static int unixDeviceCharacteristics(sqlite3_file *id){
+  unixFile *pFd = (unixFile*)id;
+  setDeviceCharacteristics(pFd);
+  return pFd->deviceCharacteristics;
+}
+
+#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
+
+/*
+** Return the system page size.
+**
+** This function should not be called directly by other code in this file.
+** Instead, it should be called via macro osGetpagesize().
+*/
+static int unixGetpagesize(void){
+#if OS_VXWORKS
+  return 1024;
+#elif defined(_BSD_SOURCE)
+  return getpagesize();
+#else
+  return (int)sysconf(_SC_PAGESIZE);
+#endif
+}
+
+#endif /* !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 */
+
+#if !defined(SQLITE_WASI) && !defined(SQLITE_OMIT_WAL)
+
+/*
+** Object used to represent an shared memory buffer.
+**
+** When multiple threads all reference the same wal-index, each thread
+** has its own unixShm object, but they all point to a single instance
+** of this unixShmNode object.  In other words, each wal-index is opened
+** only once per process.
+**
+** Each unixShmNode object is connected to a single unixInodeInfo object.
+** We could coalesce this object into unixInodeInfo, but that would mean
+** every open file that does not use shared memory (in other words, most
+** open files) would have to carry around this extra information.  So
+** the unixInodeInfo object contains a pointer to this unixShmNode object
+** and the unixShmNode object is created only when needed.
+**
+** unixMutexHeld() must be true when creating or destroying
+** this object or while reading or writing the following fields:
+**
+**      nRef
+**
+** The following fields are read-only after the object is created:
+**
+**      hShm
+**      zFilename
+**
+** Either unixShmNode.pShmMutex must be held or unixShmNode.nRef==0 and
+** unixMutexHeld() is true when reading or writing any other field
+** in this structure.
+**
+** aLock[SQLITE_SHM_NLOCK]:
+**   This array records the various locks held by clients on each of the
+**   SQLITE_SHM_NLOCK slots. If the aLock[] entry is set to 0, then no
+**   locks are held by the process on this slot. If it is set to -1, then
+**   some client holds an EXCLUSIVE lock on the locking slot. If the aLock[]
+**   value is set to a positive value, then it is the number of shared
+**   locks currently held on the slot.
+**
+** aMutex[SQLITE_SHM_NLOCK]:
+**   Normally, when SQLITE_ENABLE_SETLK_TIMEOUT is not defined, mutex
+**   pShmMutex is used to protect the aLock[] array and the right to
+**   call fcntl() on unixShmNode.hShm to obtain or release locks.
+**
+**   If SQLITE_ENABLE_SETLK_TIMEOUT is defined though, we use an array
+**   of mutexes - one for each locking slot. To read or write locking
+**   slot aLock[iSlot], the caller must hold the corresponding mutex
+**   aMutex[iSlot]. Similarly, to call fcntl() to obtain or release a
+**   lock corresponding to slot iSlot, mutex aMutex[iSlot] must be held.
+*/
+struct unixShmNode {
+  unixInodeInfo *pInode;     /* unixInodeInfo that owns this SHM node */
+  sqlite3_mutex *pShmMutex;  /* Mutex to access this object */
+  char *zFilename;           /* Name of the mmapped file */
+  int hShm;                  /* Open file descriptor */
+  int szRegion;              /* Size of shared-memory regions */
+  u16 nRegion;               /* Size of array apRegion */
+  u8 isReadonly;             /* True if read-only */
+  u8 isUnlocked;             /* True if no DMS lock held */
+  char **apRegion;           /* Array of mapped shared-memory regions */
+  int nRef;                  /* Number of unixShm objects pointing to this */
+  unixShm *pFirst;           /* All unixShm objects pointing to this */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  sqlite3_mutex *aMutex[SQLITE_SHM_NLOCK];
+#endif
+  int aLock[SQLITE_SHM_NLOCK];  /* # shared locks on slot, -1==excl lock */
+#ifdef SQLITE_DEBUG
+  u8 nextShmId;              /* Next available unixShm.id value */
+#endif
+};
+
+/*
+** Structure used internally by this VFS to record the state of an
+** open shared memory connection.
+**
+** The following fields are initialized when this object is created and
+** are read-only thereafter:
+**
+**    unixShm.pShmNode
+**    unixShm.id
+**
+** All other fields are read/write.  The unixShm.pShmNode->pShmMutex must
+** be held while accessing any read/write fields.
+*/
+struct unixShm {
+  unixShmNode *pShmNode;     /* The underlying unixShmNode object */
+  unixShm *pNext;            /* Next unixShm with the same unixShmNode */
+  u8 hasMutex;               /* True if holding the unixShmNode->pShmMutex */
+  u8 id;                     /* Id of this connection within its unixShmNode */
+  u16 sharedMask;            /* Mask of shared locks held */
+  u16 exclMask;              /* Mask of exclusive locks held */
+};
+
+/*
+** Constants used for locking
+*/
+#define UNIX_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)         /* first lock byte */
+#define UNIX_SHM_DMS    (UNIX_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */
+
+/*
+** Use F_GETLK to check whether or not there are any readers with open
+** wal-mode transactions in other processes on database file pFile. If
+** no error occurs, return SQLITE_OK and set (*piOut) to 1 if there are
+** such transactions, or 0 otherwise. If an error occurs, return an
+** SQLite error code. The final value of *piOut is undefined in this
+** case.
+*/
+static int unixFcntlExternalReader(unixFile *pFile, int *piOut){
+  int rc = SQLITE_OK;
+  *piOut = 0;
+  if( pFile->pShm){
+    unixShmNode *pShmNode = pFile->pShm->pShmNode;
+    struct flock f;
+
+    memset(&f, 0, sizeof(f));
+    f.l_type = F_WRLCK;
+    f.l_whence = SEEK_SET;
+    f.l_start = UNIX_SHM_BASE + 3;
+    f.l_len = SQLITE_SHM_NLOCK - 3;
+
+    sqlite3_mutex_enter(pShmNode->pShmMutex);
+    if( osFcntl(pShmNode->hShm, F_GETLK, &f)<0 ){
+      rc = SQLITE_IOERR_LOCK;
+    }else{
+      *piOut = (f.l_type!=F_UNLCK);
+    }
+    sqlite3_mutex_leave(pShmNode->pShmMutex);
+  }
+
+  return rc;
+}
+
+
+/*
+** Apply posix advisory locks for all bytes from ofst through ofst+n-1.
+**
+** Locks block if the mask is exactly UNIX_SHM_C and are non-blocking
+** otherwise.
+*/
+static int unixShmSystemLock(
+  unixFile *pFile,       /* Open connection to the WAL file */
+  int lockType,          /* F_UNLCK, F_RDLCK, or F_WRLCK */
+  int ofst,              /* First byte of the locking range */
+  int n                  /* Number of bytes to lock */
+){
+  unixShmNode *pShmNode; /* Apply locks to this open shared-memory segment */
+  struct flock f;        /* The posix advisory locking structure */
+  int rc = SQLITE_OK;    /* Result code form fcntl() */
+
+  pShmNode = pFile->pInode->pShmNode;
+
+  /* Assert that the parameters are within expected range and that the
+  ** correct mutex or mutexes are held. */
+  assert( pShmNode->nRef>=0 );
+  assert( (ofst==UNIX_SHM_DMS && n==1)
+       || (ofst>=UNIX_SHM_BASE && ofst+n<=(UNIX_SHM_BASE+SQLITE_SHM_NLOCK))
+  );
+  if( ofst==UNIX_SHM_DMS ){
+    assert( pShmNode->nRef>0 || unixMutexHeld() );
+    assert( pShmNode->nRef==0 || sqlite3_mutex_held(pShmNode->pShmMutex) );
+  }else{
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    int ii;
+    for(ii=ofst-UNIX_SHM_BASE; ii<ofst-UNIX_SHM_BASE+n; ii++){
+      assert( sqlite3_mutex_held(pShmNode->aMutex[ii]) );
+    }
+#else
+    assert( sqlite3_mutex_held(pShmNode->pShmMutex) );
+    assert( pShmNode->nRef>0 );
+#endif
+  }
+
+  /* Shared locks never span more than one byte */
+  assert( n==1 || lockType!=F_RDLCK );
+
+  /* Locks are within range */
+  assert( n>=1 && n<=SQLITE_SHM_NLOCK );
+  assert( ofst>=UNIX_SHM_BASE && ofst<=(UNIX_SHM_DMS+SQLITE_SHM_NLOCK) );
+
+  if( pShmNode->hShm>=0 ){
+    int res;
+    /* Initialize the locking parameters */
+    f.l_type = lockType;
+    f.l_whence = SEEK_SET;
+    f.l_start = ofst;
+    f.l_len = n;
+    res = osSetPosixAdvisoryLock(pShmNode->hShm, &f, pFile);
+    if( res==-1 ){
+#if defined(SQLITE_ENABLE_SETLK_TIMEOUT) && SQLITE_ENABLE_SETLK_TIMEOUT==1
+      rc = (pFile->iBusyTimeout ? SQLITE_BUSY_TIMEOUT : SQLITE_BUSY);
+#else
+      rc = SQLITE_BUSY;
+#endif
+    }
+  }
+
+  /* Do debug tracing */
+#ifdef SQLITE_DEBUG
+  OSTRACE(("SHM-LOCK "));
+  if( rc==SQLITE_OK ){
+    if( lockType==F_UNLCK ){
+      OSTRACE(("unlock %d..%d ok\n", ofst, ofst+n-1));
+    }else if( lockType==F_RDLCK ){
+      OSTRACE(("read-lock %d..%d ok\n", ofst, ofst+n-1));
+    }else{
+      assert( lockType==F_WRLCK );
+      OSTRACE(("write-lock %d..%d ok\n", ofst, ofst+n-1));
+    }
+  }else{
+    if( lockType==F_UNLCK ){
+      OSTRACE(("unlock %d..%d failed\n", ofst, ofst+n-1));
+    }else if( lockType==F_RDLCK ){
+      OSTRACE(("read-lock %d..%d failed\n", ofst, ofst+n-1));
+    }else{
+      assert( lockType==F_WRLCK );
+      OSTRACE(("write-lock %d..%d failed\n", ofst, ofst+n-1));
+    }
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** Return the minimum number of 32KB shm regions that should be mapped at
+** a time, assuming that each mapping must be an integer multiple of the
+** current system page-size.
+**
+** Usually, this is 1. The exception seems to be systems that are configured
+** to use 64KB pages - in this case each mapping must cover at least two
+** shm regions.
+*/
+static int unixShmRegionPerMap(void){
+  int shmsz = 32*1024;            /* SHM region size */
+  int pgsz = osGetpagesize();   /* System page size */
+  assert( ((pgsz-1)&pgsz)==0 );   /* Page size must be a power of 2 */
+  if( pgsz<shmsz ) return 1;
+  return pgsz/shmsz;
+}
+
+/*
+** Purge the unixShmNodeList list of all entries with unixShmNode.nRef==0.
+**
+** This is not a VFS shared-memory method; it is a utility function called
+** by VFS shared-memory methods.
+*/
+static void unixShmPurge(unixFile *pFd){
+  unixShmNode *p = pFd->pInode->pShmNode;
+  assert( unixMutexHeld() );
+  if( p && ALWAYS(p->nRef==0) ){
+    int nShmPerMap = unixShmRegionPerMap();
+    int i;
+    assert( p->pInode==pFd->pInode );
+    sqlite3_mutex_free(p->pShmMutex);
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    for(i=0; i<SQLITE_SHM_NLOCK; i++){
+      sqlite3_mutex_free(p->aMutex[i]);
+    }
+#endif
+    for(i=0; i<p->nRegion; i+=nShmPerMap){
+      if( p->hShm>=0 ){
+        osMunmap(p->apRegion[i], p->szRegion);
+      }else{
+        sqlite3_free(p->apRegion[i]);
+      }
+    }
+    sqlite3_free(p->apRegion);
+    if( p->hShm>=0 ){
+      robust_close(pFd, p->hShm, __LINE__);
+      p->hShm = -1;
+    }
+    p->pInode->pShmNode = 0;
+    sqlite3_free(p);
+  }
+}
+
+/*
+** The DMS lock has not yet been taken on shm file pShmNode. Attempt to
+** take it now. Return SQLITE_OK if successful, or an SQLite error
+** code otherwise.
+**
+** If the DMS cannot be locked because this is a readonly_shm=1
+** connection and no other process already holds a lock, return
+** SQLITE_READONLY_CANTINIT and set pShmNode->isUnlocked=1.
+*/
+static int unixLockSharedMemory(unixFile *pDbFd, unixShmNode *pShmNode){
+  struct flock lock;
+  int rc = SQLITE_OK;
+
+  /* Use F_GETLK to determine the locks other processes are holding
+  ** on the DMS byte. If it indicates that another process is holding
+  ** a SHARED lock, then this process may also take a SHARED lock
+  ** and proceed with opening the *-shm file.
+  **
+  ** Or, if no other process is holding any lock, then this process
+  ** is the first to open it. In this case take an EXCLUSIVE lock on the
+  ** DMS byte and truncate the *-shm file to zero bytes in size. Then
+  ** downgrade to a SHARED lock on the DMS byte.
+  **
+  ** If another process is holding an EXCLUSIVE lock on the DMS byte,
+  ** return SQLITE_BUSY to the caller (it will try again). An earlier
+  ** version of this code attempted the SHARED lock at this point. But
+  ** this introduced a subtle race condition: if the process holding
+  ** EXCLUSIVE failed just before truncating the *-shm file, then this
+  ** process might open and use the *-shm file without truncating it.
+  ** And if the *-shm file has been corrupted by a power failure or
+  ** system crash, the database itself may also become corrupt.  */
+  lock.l_whence = SEEK_SET;
+  lock.l_start = UNIX_SHM_DMS;
+  lock.l_len = 1;
+  lock.l_type = F_WRLCK;
+  if( osFcntl(pShmNode->hShm, F_GETLK, &lock)!=0 ) {
+    rc = SQLITE_IOERR_LOCK;
+  }else if( lock.l_type==F_UNLCK ){
+    if( pShmNode->isReadonly ){
+      pShmNode->isUnlocked = 1;
+      rc = SQLITE_READONLY_CANTINIT;
+    }else{
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+      /* Do not use a blocking lock here. If the lock cannot be obtained
+      ** immediately, it means some other connection is truncating the
+      ** *-shm file. And after it has done so, it will not release its
+      ** lock, but only downgrade it to a shared lock. So no point in
+      ** blocking here. The call below to obtain the shared DMS lock may
+      ** use a blocking lock. */
+      int iSaveTimeout = pDbFd->iBusyTimeout;
+      pDbFd->iBusyTimeout = 0;
+#endif
+      rc = unixShmSystemLock(pDbFd, F_WRLCK, UNIX_SHM_DMS, 1);
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+      pDbFd->iBusyTimeout = iSaveTimeout;
+#endif
+      /* The first connection to attach must truncate the -shm file.  We
+      ** truncate to 3 bytes (an arbitrary small number, less than the
+      ** -shm header size) rather than 0 as a system debugging aid, to
+      ** help detect if a -shm file truncation is legitimate or is the work
+      ** or a rogue process. */
+      if( rc==SQLITE_OK && robust_ftruncate(pShmNode->hShm, 3) ){
+        rc = unixLogError(SQLITE_IOERR_SHMOPEN,"ftruncate",pShmNode->zFilename);
+      }
+    }
+  }else if( lock.l_type==F_WRLCK ){
+    rc = SQLITE_BUSY;
+  }
+
+  if( rc==SQLITE_OK ){
+    assert( lock.l_type==F_UNLCK || lock.l_type==F_RDLCK );
+    rc = unixShmSystemLock(pDbFd, F_RDLCK, UNIX_SHM_DMS, 1);
+  }
+  return rc;
+}
+
+/*
+** Open a shared-memory area associated with open database file pDbFd.
+** This particular implementation uses mmapped files.
+**
+** The file used to implement shared-memory is in the same directory
+** as the open database file and has the same name as the open database
+** file with the "-shm" suffix added.  For example, if the database file
+** is "/home/user1/config.db" then the file that is created and mmapped
+** for shared memory will be called "/home/user1/config.db-shm".
+**
+** Another approach to is to use files in /dev/shm or /dev/tmp or an
+** some other tmpfs mount. But if a file in a different directory
+** from the database file is used, then differing access permissions
+** or a chroot() might cause two different processes on the same
+** database to end up using different files for shared memory -
+** meaning that their memory would not really be shared - resulting
+** in database corruption.  Nevertheless, this tmpfs file usage
+** can be enabled at compile-time using -DSQLITE_SHM_DIRECTORY="/dev/shm"
+** or the equivalent.  The use of the SQLITE_SHM_DIRECTORY compile-time
+** option results in an incompatible build of SQLite;  builds of SQLite
+** that with differing SQLITE_SHM_DIRECTORY settings attempt to use the
+** same database file at the same time, database corruption will likely
+** result. The SQLITE_SHM_DIRECTORY compile-time option is considered
+** "unsupported" and may go away in a future SQLite release.
+**
+** When opening a new shared-memory file, if no other instances of that
+** file are currently open, in this process or in other processes, then
+** the file must be truncated to zero length or have its header cleared.
+**
+** If the original database file (pDbFd) is using the "unix-excl" VFS
+** that means that an exclusive lock is held on the database file and
+** that no other processes are able to read or write the database.  In
+** that case, we do not really need shared memory.  No shared memory
+** file is created.  The shared memory will be simulated with heap memory.
+*/
+static int unixOpenSharedMemory(unixFile *pDbFd){
+  struct unixShm *p = 0;          /* The connection to be opened */
+  struct unixShmNode *pShmNode;   /* The underlying mmapped file */
+  int rc = SQLITE_OK;             /* Result code */
+  unixInodeInfo *pInode;          /* The inode of fd */
+  char *zShm;             /* Name of the file used for SHM */
+  int nShmFilename;               /* Size of the SHM filename in bytes */
+
+  /* Allocate space for the new unixShm object. */
+  p = sqlite3_malloc64( sizeof(*p) );
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  memset(p, 0, sizeof(*p));
+  assert( pDbFd->pShm==0 );
+
+  /* Check to see if a unixShmNode object already exists. Reuse an existing
+  ** one if present. Create a new one if necessary.
+  */
+  assert( unixFileMutexNotheld(pDbFd) );
+  unixEnterMutex();
+  pInode = pDbFd->pInode;
+  pShmNode = pInode->pShmNode;
+  if( pShmNode==0 ){
+    struct stat sStat;                 /* fstat() info for database file */
+#ifndef SQLITE_SHM_DIRECTORY
+    const char *zBasePath = pDbFd->zPath;
+#endif
+
+    /* Call fstat() to figure out the permissions on the database file. If
+    ** a new *-shm file is created, an attempt will be made to create it
+    ** with the same permissions.
+    */
+    if( osFstat(pDbFd->h, &sStat) ){
+      rc = SQLITE_IOERR_FSTAT;
+      goto shm_open_err;
+    }
+
+#ifdef SQLITE_SHM_DIRECTORY
+    nShmFilename = sizeof(SQLITE_SHM_DIRECTORY) + 31;
+#else
+    nShmFilename = 6 + (int)strlen(zBasePath);
+#endif
+    pShmNode = sqlite3_malloc64( sizeof(*pShmNode) + nShmFilename );
+    if( pShmNode==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto shm_open_err;
+    }
+    memset(pShmNode, 0, sizeof(*pShmNode)+nShmFilename);
+    zShm = pShmNode->zFilename = (char*)&pShmNode[1];
+#ifdef SQLITE_SHM_DIRECTORY
+    sqlite3_snprintf(nShmFilename, zShm,
+                     SQLITE_SHM_DIRECTORY "/sqlite-shm-%x-%x",
+                     (u32)sStat.st_ino, (u32)sStat.st_dev);
+#else
+    sqlite3_snprintf(nShmFilename, zShm, "%s-shm", zBasePath);
+    sqlite3FileSuffix3(pDbFd->zPath, zShm);
+#endif
+    pShmNode->hShm = -1;
+    pDbFd->pInode->pShmNode = pShmNode;
+    pShmNode->pInode = pDbFd->pInode;
+    if( sqlite3GlobalConfig.bCoreMutex ){
+      pShmNode->pShmMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+      if( pShmNode->pShmMutex==0 ){
+        rc = SQLITE_NOMEM_BKPT;
+        goto shm_open_err;
+      }
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+      {
+        int ii;
+        for(ii=0; ii<SQLITE_SHM_NLOCK; ii++){
+          pShmNode->aMutex[ii] = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+          if( pShmNode->aMutex[ii]==0 ){
+            rc = SQLITE_NOMEM_BKPT;
+            goto shm_open_err;
+          }
+        }
+      }
+#endif
+    }
+
+    if( pInode->bProcessLock==0 ){
+      if( 0==sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){
+        pShmNode->hShm = robust_open(zShm, O_RDWR|O_CREAT|O_NOFOLLOW,
+                                     (sStat.st_mode&0777));
+      }
+      if( pShmNode->hShm<0 ){
+        pShmNode->hShm = robust_open(zShm, O_RDONLY|O_NOFOLLOW,
+                                     (sStat.st_mode&0777));
+        if( pShmNode->hShm<0 ){
+          rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShm);
+          goto shm_open_err;
+        }
+        pShmNode->isReadonly = 1;
+      }
+
+      /* If this process is running as root, make sure that the SHM file
+      ** is owned by the same user that owns the original database.  Otherwise,
+      ** the original owner will not be able to connect.
+      */
+      robustFchown(pShmNode->hShm, sStat.st_uid, sStat.st_gid);
+
+      rc = unixLockSharedMemory(pDbFd, pShmNode);
+      if( rc!=SQLITE_OK && rc!=SQLITE_READONLY_CANTINIT ) goto shm_open_err;
+    }
+  }
+
+  /* Make the new connection a child of the unixShmNode */
+  p->pShmNode = pShmNode;
+#ifdef SQLITE_DEBUG
+  p->id = pShmNode->nextShmId++;
+#endif
+  pShmNode->nRef++;
+  pDbFd->pShm = p;
+  unixLeaveMutex();
+
+  /* The reference count on pShmNode has already been incremented under
+  ** the cover of the unixEnterMutex() mutex and the pointer from the
+  ** new (struct unixShm) object to the pShmNode has been set. All that is
+  ** left to do is to link the new object into the linked list starting
+  ** at pShmNode->pFirst. This must be done while holding the
+  ** pShmNode->pShmMutex.
+  */
+  sqlite3_mutex_enter(pShmNode->pShmMutex);
+  p->pNext = pShmNode->pFirst;
+  pShmNode->pFirst = p;
+  sqlite3_mutex_leave(pShmNode->pShmMutex);
+  return rc;
+
+  /* Jump here on any error */
+shm_open_err:
+  unixShmPurge(pDbFd);       /* This call frees pShmNode if required */
+  sqlite3_free(p);
+  unixLeaveMutex();
+  return rc;
+}
+
+/*
+** This function is called to obtain a pointer to region iRegion of the
+** shared-memory associated with the database file fd. Shared-memory regions
+** are numbered starting from zero. Each shared-memory region is szRegion
+** bytes in size.
+**
+** If an error occurs, an error code is returned and *pp is set to NULL.
+**
+** Otherwise, if the bExtend parameter is 0 and the requested shared-memory
+** region has not been allocated (by any client, including one running in a
+** separate process), then *pp is set to NULL and SQLITE_OK returned. If
+** bExtend is non-zero and the requested shared-memory region has not yet
+** been allocated, it is allocated by this function.
+**
+** If the shared-memory region has already been allocated or is allocated by
+** this call as described above, then it is mapped into this processes
+** address space (if it is not already), *pp is set to point to the mapped
+** memory and SQLITE_OK returned.
+*/
+static int unixShmMap(
+  sqlite3_file *fd,               /* Handle open on database file */
+  int iRegion,                    /* Region to retrieve */
+  int szRegion,                   /* Size of regions */
+  int bExtend,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Mapped memory */
+){
+  unixFile *pDbFd = (unixFile*)fd;
+  unixShm *p;
+  unixShmNode *pShmNode;
+  int rc = SQLITE_OK;
+  int nShmPerMap = unixShmRegionPerMap();
+  int nReqRegion;
+
+  /* If the shared-memory file has not yet been opened, open it now. */
+  if( pDbFd->pShm==0 ){
+    rc = unixOpenSharedMemory(pDbFd);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  p = pDbFd->pShm;
+  pShmNode = p->pShmNode;
+  sqlite3_mutex_enter(pShmNode->pShmMutex);
+  if( pShmNode->isUnlocked ){
+    rc = unixLockSharedMemory(pDbFd, pShmNode);
+    if( rc!=SQLITE_OK ) goto shmpage_out;
+    pShmNode->isUnlocked = 0;
+  }
+  assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
+  assert( pShmNode->pInode==pDbFd->pInode );
+  assert( pShmNode->hShm>=0 || pDbFd->pInode->bProcessLock==1 );
+  assert( pShmNode->hShm<0 || pDbFd->pInode->bProcessLock==0 );
+
+  /* Minimum number of regions required to be mapped. */
+  nReqRegion = ((iRegion+nShmPerMap) / nShmPerMap) * nShmPerMap;
+
+  if( pShmNode->nRegion<nReqRegion ){
+    char **apNew;                      /* New apRegion[] array */
+    int nByte = nReqRegion*szRegion;   /* Minimum required file size */
+    struct stat sStat;                 /* Used by fstat() */
+
+    pShmNode->szRegion = szRegion;
+
+    if( pShmNode->hShm>=0 ){
+      /* The requested region is not mapped into this processes address space.
+      ** Check to see if it has been allocated (i.e. if the wal-index file is
+      ** large enough to contain the requested region).
+      */
+      if( osFstat(pShmNode->hShm, &sStat) ){
+        rc = SQLITE_IOERR_SHMSIZE;
+        goto shmpage_out;
+      }
+
+      if( sStat.st_size<nByte ){
+        /* The requested memory region does not exist. If bExtend is set to
+        ** false, exit early. *pp will be set to NULL and SQLITE_OK returned.
+        */
+        if( !bExtend ){
+          goto shmpage_out;
+        }
+
+        /* Alternatively, if bExtend is true, extend the file. Do this by
+        ** writing a single byte to the end of each (OS) page being
+        ** allocated or extended. Technically, we need only write to the
+        ** last page in order to extend the file. But writing to all new
+        ** pages forces the OS to allocate them immediately, which reduces
+        ** the chances of SIGBUS while accessing the mapped region later on.
+        */
+        else{
+          static const int pgsz = 4096;
+          int iPg;
+
+          /* Write to the last byte of each newly allocated or extended page */
+          assert( (nByte % pgsz)==0 );
+          for(iPg=(sStat.st_size/pgsz); iPg<(nByte/pgsz); iPg++){
+            int x = 0;
+            if( seekAndWriteFd(pShmNode->hShm, iPg*pgsz + pgsz-1,"",1,&x)!=1 ){
+              const char *zFile = pShmNode->zFilename;
+              rc = unixLogError(SQLITE_IOERR_SHMSIZE, "write", zFile);
+              goto shmpage_out;
+            }
+          }
+        }
+      }
+    }
+
+    /* Map the requested memory region into this processes address space. */
+    apNew = (char **)sqlite3_realloc(
+        pShmNode->apRegion, nReqRegion*sizeof(char *)
+    );
+    if( !apNew ){
+      rc = SQLITE_IOERR_NOMEM_BKPT;
+      goto shmpage_out;
+    }
+    pShmNode->apRegion = apNew;
+    while( pShmNode->nRegion<nReqRegion ){
+      int nMap = szRegion*nShmPerMap;
+      int i;
+      void *pMem;
+      if( pShmNode->hShm>=0 ){
+        pMem = osMmap(0, nMap,
+            pShmNode->isReadonly ? PROT_READ : PROT_READ|PROT_WRITE,
+            MAP_SHARED, pShmNode->hShm, szRegion*(i64)pShmNode->nRegion
+        );
+        if( pMem==MAP_FAILED ){
+          rc = unixLogError(SQLITE_IOERR_SHMMAP, "mmap", pShmNode->zFilename);
+          goto shmpage_out;
+        }
+      }else{
+        pMem = sqlite3_malloc64(nMap);
+        if( pMem==0 ){
+          rc = SQLITE_NOMEM_BKPT;
+          goto shmpage_out;
+        }
+        memset(pMem, 0, nMap);
+      }
+
+      for(i=0; i<nShmPerMap; i++){
+        pShmNode->apRegion[pShmNode->nRegion+i] = &((char*)pMem)[szRegion*i];
+      }
+      pShmNode->nRegion += nShmPerMap;
+    }
+  }
+
+shmpage_out:
+  if( pShmNode->nRegion>iRegion ){
+    *pp = pShmNode->apRegion[iRegion];
+  }else{
+    *pp = 0;
+  }
+  if( pShmNode->isReadonly && rc==SQLITE_OK ) rc = SQLITE_READONLY;
+  sqlite3_mutex_leave(pShmNode->pShmMutex);
+  return rc;
+}
+
+/*
+** Check that the pShmNode->aLock[] array comports with the locking bitmasks
+** held by each client. Return true if it does, or false otherwise. This
+** is to be used in an assert(). e.g.
+**
+**     assert( assertLockingArrayOk(pShmNode) );
+*/
+#ifdef SQLITE_DEBUG
+static int assertLockingArrayOk(unixShmNode *pShmNode){
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  return 1;
+#else
+  unixShm *pX;
+  int aLock[SQLITE_SHM_NLOCK];
+
+  memset(aLock, 0, sizeof(aLock));
+  for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+    int i;
+    for(i=0; i<SQLITE_SHM_NLOCK; i++){
+      if( pX->exclMask & (1<<i) ){
+        assert( aLock[i]==0 );
+        aLock[i] = -1;
+      }else if( pX->sharedMask & (1<<i) ){
+        assert( aLock[i]>=0 );
+        aLock[i]++;
+      }
+    }
+  }
+
+  assert( 0==memcmp(pShmNode->aLock, aLock, sizeof(aLock)) );
+  return (memcmp(pShmNode->aLock, aLock, sizeof(aLock))==0);
+#endif
+}
+#endif
+
+/*
+** Change the lock state for a shared-memory segment.
+**
+** Note that the relationship between SHARED and EXCLUSIVE locks is a little
+** different here than in posix.  In xShmLock(), one can go from unlocked
+** to shared and back or from unlocked to exclusive and back.  But one may
+** not go from shared to exclusive or from exclusive to shared.
+*/
+static int unixShmLock(
+  sqlite3_file *fd,          /* Database file holding the shared memory */
+  int ofst,                  /* First lock to acquire or release */
+  int n,                     /* Number of locks to acquire or release */
+  int flags                  /* What to do with the lock */
+){
+  unixFile *pDbFd = (unixFile*)fd;      /* Connection holding shared memory */
+  unixShm *p;                           /* The shared memory being locked */
+  unixShmNode *pShmNode;                /* The underlying file iNode */
+  int rc = SQLITE_OK;                   /* Result code */
+  u16 mask = (1<<(ofst+n)) - (1<<ofst); /* Mask of locks to take or release */
+  int *aLock;
+
+  p = pDbFd->pShm;
+  if( p==0 ) return SQLITE_IOERR_SHMLOCK;
+  pShmNode = p->pShmNode;
+  if( NEVER(pShmNode==0) ) return SQLITE_IOERR_SHMLOCK;
+  aLock = pShmNode->aLock;
+
+  assert( pShmNode==pDbFd->pInode->pShmNode );
+  assert( pShmNode->pInode==pDbFd->pInode );
+  assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK );
+  assert( n>=1 );
+  assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) );
+  assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 );
+  assert( pShmNode->hShm>=0 || pDbFd->pInode->bProcessLock==1 );
+  assert( pShmNode->hShm<0 || pDbFd->pInode->bProcessLock==0 );
+
+  /* Check that, if this to be a blocking lock, no locks that occur later
+  ** in the following list than the lock being obtained are already held:
+  **
+  **   1. Checkpointer lock (ofst==1).
+  **   2. Write lock (ofst==0).
+  **   3. Read locks (ofst>=3 && ofst<SQLITE_SHM_NLOCK).
+  **
+  ** In other words, if this is a blocking lock, none of the locks that
+  ** occur later in the above list than the lock being obtained may be
+  ** held.
+  **
+  ** It is not permitted to block on the RECOVER lock.
+  */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  {
+    u16 lockMask = (p->exclMask|p->sharedMask);
+    assert( (flags & SQLITE_SHM_UNLOCK) || pDbFd->iBusyTimeout==0 || (
+          (ofst!=2)                                   /* not RECOVER */
+       && (ofst!=1 || lockMask==0 || lockMask==2)
+       && (ofst!=0 || lockMask<3)
+       && (ofst<3  || lockMask<(1<<ofst))
+    ));
+  }
+#endif
+
+  /* Check if there is any work to do. There are three cases:
+  **
+  **    a) An unlock operation where there are locks to unlock,
+  **    b) An shared lock where the requested lock is not already held
+  **    c) An exclusive lock where the requested lock is not already held
+  **
+  ** The SQLite core never requests an exclusive lock that it already holds.
+  ** This is assert()ed below.
+  */
+  assert( flags!=(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK)
+       || 0==(p->exclMask & mask)
+  );
+  if( ((flags & SQLITE_SHM_UNLOCK) && ((p->exclMask|p->sharedMask) & mask))
+   || (flags==(SQLITE_SHM_SHARED|SQLITE_SHM_LOCK) && 0==(p->sharedMask & mask))
+   || (flags==(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK))
+  ){
+
+    /* Take the required mutexes. In SETLK_TIMEOUT mode (blocking locks), if
+    ** this is an attempt on an exclusive lock use sqlite3_mutex_try(). If any
+    ** other thread is holding this mutex, then it is either holding or about
+    ** to hold a lock exclusive to the one being requested, and we may
+    ** therefore return SQLITE_BUSY to the caller.
+    **
+    ** Doing this prevents some deadlock scenarios. For example, thread 1 may
+    ** be a checkpointer blocked waiting on the WRITER lock. And thread 2
+    ** may be a normal SQL client upgrading to a write transaction. In this
+    ** case thread 2 does a non-blocking request for the WRITER lock. But -
+    ** if it were to use sqlite3_mutex_enter() then it would effectively
+    ** become a (doomed) blocking request, as thread 2 would block until thread
+    ** 1 obtained WRITER and released the mutex. Since thread 2 already holds
+    ** a lock on a read-locking slot at this point, this breaks the
+    ** anti-deadlock rules (see above).  */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    int iMutex;
+    for(iMutex=ofst; iMutex<ofst+n; iMutex++){
+      if( flags==(SQLITE_SHM_LOCK|SQLITE_SHM_EXCLUSIVE) ){
+        rc = sqlite3_mutex_try(pShmNode->aMutex[iMutex]);
+        if( rc!=SQLITE_OK ) goto leave_shmnode_mutexes;
+      }else{
+        sqlite3_mutex_enter(pShmNode->aMutex[iMutex]);
+      }
+    }
+#else
+    sqlite3_mutex_enter(pShmNode->pShmMutex);
+#endif
+
+    if( ALWAYS(rc==SQLITE_OK) ){
+      if( flags & SQLITE_SHM_UNLOCK ){
+        /* Case (a) - unlock.  */
+        int bUnlock = 1;
+        assert( (p->exclMask & p->sharedMask)==0 );
+        assert( !(flags & SQLITE_SHM_EXCLUSIVE) || (p->exclMask & mask)==mask );
+        assert( !(flags & SQLITE_SHM_SHARED) || (p->sharedMask & mask)==mask );
+
+        /* If this is a SHARED lock being unlocked, it is possible that other
+        ** clients within this process are holding the same SHARED lock. In
+        ** this case, set bUnlock to 0 so that the posix lock is not removed
+        ** from the file-descriptor below.  */
+        if( flags & SQLITE_SHM_SHARED ){
+          assert( n==1 );
+          assert( aLock[ofst]>=1 );
+          if( aLock[ofst]>1 ){
+            bUnlock = 0;
+            aLock[ofst]--;
+            p->sharedMask &= ~mask;
+          }
+        }
+
+        if( bUnlock ){
+          rc = unixShmSystemLock(pDbFd, F_UNLCK, ofst+UNIX_SHM_BASE, n);
+          if( rc==SQLITE_OK ){
+            memset(&aLock[ofst], 0, sizeof(int)*n);
+            p->sharedMask &= ~mask;
+            p->exclMask &= ~mask;
+          }
+        }
+      }else if( flags & SQLITE_SHM_SHARED ){
+        /* Case (b) - a shared lock.  */
+
+        if( aLock[ofst]<0 ){
+          /* An exclusive lock is held by some other connection. BUSY. */
+          rc = SQLITE_BUSY;
+        }else if( aLock[ofst]==0 ){
+          rc = unixShmSystemLock(pDbFd, F_RDLCK, ofst+UNIX_SHM_BASE, n);
+        }
+
+        /* Get the local shared locks */
+        if( rc==SQLITE_OK ){
+          p->sharedMask |= mask;
+          aLock[ofst]++;
+        }
+      }else{
+        /* Case (c) - an exclusive lock.  */
+        int ii;
+
+        assert( flags==(SQLITE_SHM_LOCK|SQLITE_SHM_EXCLUSIVE) );
+        assert( (p->sharedMask & mask)==0 );
+        assert( (p->exclMask & mask)==0 );
+
+        /* Make sure no sibling connections hold locks that will block this
+        ** lock.  If any do, return SQLITE_BUSY right away.  */
+        for(ii=ofst; ii<ofst+n; ii++){
+          if( aLock[ii] ){
+            rc = SQLITE_BUSY;
+            break;
+          }
+        }
+
+        /* Get the exclusive locks at the system level. Then if successful
+        ** also update the in-memory values. */
+        if( rc==SQLITE_OK ){
+          rc = unixShmSystemLock(pDbFd, F_WRLCK, ofst+UNIX_SHM_BASE, n);
+          if( rc==SQLITE_OK ){
+            p->exclMask |= mask;
+            for(ii=ofst; ii<ofst+n; ii++){
+              aLock[ii] = -1;
+            }
+          }
+        }
+      }
+      assert( assertLockingArrayOk(pShmNode) );
+    }
+
+    /* Drop the mutexes acquired above. */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  leave_shmnode_mutexes:
+    for(iMutex--; iMutex>=ofst; iMutex--){
+      sqlite3_mutex_leave(pShmNode->aMutex[iMutex]);
+    }
+#else
+    sqlite3_mutex_leave(pShmNode->pShmMutex);
+#endif
+  }
+
+  OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x\n",
+           p->id, osGetpid(0), p->sharedMask, p->exclMask));
+  return rc;
+}
+
+/*
+** Implement a memory barrier or memory fence on shared memory.
+**
+** All loads and stores begun before the barrier must complete before
+** any load or store begun after the barrier.
+*/
+static void unixShmBarrier(
+  sqlite3_file *fd                /* Database file holding the shared memory */
+){
+  UNUSED_PARAMETER(fd);
+  sqlite3MemoryBarrier();         /* compiler-defined memory barrier */
+  assert( fd->pMethods->xLock==nolockLock
+       || unixFileMutexNotheld((unixFile*)fd)
+  );
+  unixEnterMutex();               /* Also mutex, for redundancy */
+  unixLeaveMutex();
+}
+
+/*
+** Close a connection to shared-memory.  Delete the underlying
+** storage if deleteFlag is true.
+**
+** If there is no shared memory associated with the connection then this
+** routine is a harmless no-op.
+*/
+static int unixShmUnmap(
+  sqlite3_file *fd,               /* The underlying database file */
+  int deleteFlag                  /* Delete shared-memory if true */
+){
+  unixShm *p;                     /* The connection to be closed */
+  unixShmNode *pShmNode;          /* The underlying shared-memory file */
+  unixShm **pp;                   /* For looping over sibling connections */
+  unixFile *pDbFd;                /* The underlying database file */
+
+  pDbFd = (unixFile*)fd;
+  p = pDbFd->pShm;
+  if( p==0 ) return SQLITE_OK;
+  pShmNode = p->pShmNode;
+
+  assert( pShmNode==pDbFd->pInode->pShmNode );
+  assert( pShmNode->pInode==pDbFd->pInode );
+
+  /* Remove connection p from the set of connections associated
+  ** with pShmNode */
+  sqlite3_mutex_enter(pShmNode->pShmMutex);
+  for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
+  *pp = p->pNext;
+
+  /* Free the connection p */
+  sqlite3_free(p);
+  pDbFd->pShm = 0;
+  sqlite3_mutex_leave(pShmNode->pShmMutex);
+
+  /* If pShmNode->nRef has reached 0, then close the underlying
+  ** shared-memory file, too */
+  assert( unixFileMutexNotheld(pDbFd) );
+  unixEnterMutex();
+  assert( pShmNode->nRef>0 );
+  pShmNode->nRef--;
+  if( pShmNode->nRef==0 ){
+    if( deleteFlag && pShmNode->hShm>=0 ){
+      osUnlink(pShmNode->zFilename);
+    }
+    unixShmPurge(pDbFd);
+  }
+  unixLeaveMutex();
+
+  return SQLITE_OK;
+}
+
+
+#else
+# define unixShmMap     0
+# define unixShmLock    0
+# define unixShmBarrier 0
+# define unixShmUnmap   0
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/*
+** If it is currently memory mapped, unmap file pFd.
+*/
+static void unixUnmapfile(unixFile *pFd){
+  assert( pFd->nFetchOut==0 );
+  if( pFd->pMapRegion ){
+    osMunmap(pFd->pMapRegion, pFd->mmapSizeActual);
+    pFd->pMapRegion = 0;
+    pFd->mmapSize = 0;
+    pFd->mmapSizeActual = 0;
+  }
+}
+
+/*
+** Attempt to set the size of the memory mapping maintained by file
+** descriptor pFd to nNew bytes. Any existing mapping is discarded.
+**
+** If successful, this function sets the following variables:
+**
+**       unixFile.pMapRegion
+**       unixFile.mmapSize
+**       unixFile.mmapSizeActual
+**
+** If unsuccessful, an error message is logged via sqlite3_log() and
+** the three variables above are zeroed. In this case SQLite should
+** continue accessing the database using the xRead() and xWrite()
+** methods.
+*/
+static void unixRemapfile(
+  unixFile *pFd,                  /* File descriptor object */
+  i64 nNew                        /* Required mapping size */
+){
+  const char *zErr = "mmap";
+  int h = pFd->h;                      /* File descriptor open on db file */
+  u8 *pOrig = (u8 *)pFd->pMapRegion;   /* Pointer to current file mapping */
+  i64 nOrig = pFd->mmapSizeActual;     /* Size of pOrig region in bytes */
+  u8 *pNew = 0;                        /* Location of new mapping */
+  int flags = PROT_READ;               /* Flags to pass to mmap() */
+
+  assert( pFd->nFetchOut==0 );
+  assert( nNew>pFd->mmapSize );
+  assert( nNew<=pFd->mmapSizeMax );
+  assert( nNew>0 );
+  assert( pFd->mmapSizeActual>=pFd->mmapSize );
+  assert( MAP_FAILED!=0 );
+
+#ifdef SQLITE_MMAP_READWRITE
+  if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE;
+#endif
+
+  if( pOrig ){
+#if HAVE_MREMAP
+    i64 nReuse = pFd->mmapSize;
+#else
+    const int szSyspage = osGetpagesize();
+    i64 nReuse = (pFd->mmapSize & ~(szSyspage-1));
+#endif
+    u8 *pReq = &pOrig[nReuse];
+
+    /* Unmap any pages of the existing mapping that cannot be reused. */
+    if( nReuse!=nOrig ){
+      osMunmap(pReq, nOrig-nReuse);
+    }
+
+#if HAVE_MREMAP
+    pNew = osMremap(pOrig, nReuse, nNew, MREMAP_MAYMOVE);
+    zErr = "mremap";
+#else
+    pNew = osMmap(pReq, nNew-nReuse, flags, MAP_SHARED, h, nReuse);
+    if( pNew!=MAP_FAILED ){
+      if( pNew!=pReq ){
+        osMunmap(pNew, nNew - nReuse);
+        pNew = 0;
+      }else{
+        pNew = pOrig;
+      }
+    }
+#endif
+
+    /* The attempt to extend the existing mapping failed. Free it. */
+    if( pNew==MAP_FAILED || pNew==0 ){
+      osMunmap(pOrig, nReuse);
+    }
+  }
+
+  /* If pNew is still NULL, try to create an entirely new mapping. */
+  if( pNew==0 ){
+    pNew = osMmap(0, nNew, flags, MAP_SHARED, h, 0);
+  }
+
+  if( pNew==MAP_FAILED ){
+    pNew = 0;
+    nNew = 0;
+    unixLogError(SQLITE_OK, zErr, pFd->zPath);
+
+    /* If the mmap() above failed, assume that all subsequent mmap() calls
+    ** will probably fail too. Fall back to using xRead/xWrite exclusively
+    ** in this case.  */
+    pFd->mmapSizeMax = 0;
+  }
+  pFd->pMapRegion = (void *)pNew;
+  pFd->mmapSize = pFd->mmapSizeActual = nNew;
+}
+
+/*
+** Memory map or remap the file opened by file-descriptor pFd (if the file
+** is already mapped, the existing mapping is replaced by the new). Or, if
+** there already exists a mapping for this file, and there are still
+** outstanding xFetch() references to it, this function is a no-op.
+**
+** If parameter nByte is non-negative, then it is the requested size of
+** the mapping to create. Otherwise, if nByte is less than zero, then the
+** requested size is the size of the file on disk. The actual size of the
+** created mapping is either the requested size or the value configured
+** using SQLITE_FCNTL_MMAP_LIMIT, whichever is smaller.
+**
+** SQLITE_OK is returned if no error occurs (even if the mapping is not
+** recreated as a result of outstanding references) or an SQLite error
+** code otherwise.
+*/
+static int unixMapfile(unixFile *pFd, i64 nMap){
+  assert( nMap>=0 || pFd->nFetchOut==0 );
+  assert( nMap>0 || (pFd->mmapSize==0 && pFd->pMapRegion==0) );
+  if( pFd->nFetchOut>0 ) return SQLITE_OK;
+
+  if( nMap<0 ){
+    struct stat statbuf;          /* Low-level file information */
+    if( osFstat(pFd->h, &statbuf) ){
+      return SQLITE_IOERR_FSTAT;
+    }
+    nMap = statbuf.st_size;
+  }
+  if( nMap>pFd->mmapSizeMax ){
+    nMap = pFd->mmapSizeMax;
+  }
+
+  assert( nMap>0 || (pFd->mmapSize==0 && pFd->pMapRegion==0) );
+  if( nMap!=pFd->mmapSize ){
+    unixRemapfile(pFd, nMap);
+  }
+
+  return SQLITE_OK;
+}
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+
+/*
+** If possible, return a pointer to a mapping of file fd starting at offset
+** iOff. The mapping must be valid for at least nAmt bytes.
+**
+** If such a pointer can be obtained, store it in *pp and return SQLITE_OK.
+** Or, if one cannot but no error occurs, set *pp to 0 and return SQLITE_OK.
+** Finally, if an error does occur, return an SQLite error code. The final
+** value of *pp is undefined in this case.
+**
+** If this function does return a pointer, the caller must eventually
+** release the reference by calling unixUnfetch().
+*/
+static int unixFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){
+#if SQLITE_MAX_MMAP_SIZE>0
+  unixFile *pFd = (unixFile *)fd;   /* The underlying database file */
+#endif
+  *pp = 0;
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFd->mmapSizeMax>0 ){
+    /* Ensure that there is always at least a 256 byte buffer of addressable
+    ** memory following the returned page. If the database is corrupt,
+    ** SQLite may overread the page slightly (in practice only a few bytes,
+    ** but 256 is safe, round, number).  */
+    const int nEofBuffer = 256;
+    if( pFd->pMapRegion==0 ){
+      int rc = unixMapfile(pFd, -1);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    if( pFd->mmapSize >= (iOff+nAmt+nEofBuffer) ){
+      *pp = &((u8 *)pFd->pMapRegion)[iOff];
+      pFd->nFetchOut++;
+    }
+  }
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** If the third argument is non-NULL, then this function releases a
+** reference obtained by an earlier call to unixFetch(). The second
+** argument passed to this function must be the same as the corresponding
+** argument that was passed to the unixFetch() invocation.
+**
+** Or, if the third argument is NULL, then this function is being called
+** to inform the VFS layer that, according to POSIX, any existing mapping
+** may now be invalid and should be unmapped.
+*/
+static int unixUnfetch(sqlite3_file *fd, i64 iOff, void *p){
+#if SQLITE_MAX_MMAP_SIZE>0
+  unixFile *pFd = (unixFile *)fd;   /* The underlying database file */
+  UNUSED_PARAMETER(iOff);
+
+  /* If p==0 (unmap the entire file) then there must be no outstanding
+  ** xFetch references. Or, if p!=0 (meaning it is an xFetch reference),
+  ** then there must be at least one outstanding.  */
+  assert( (p==0)==(pFd->nFetchOut==0) );
+
+  /* If p!=0, it must match the iOff value. */
+  assert( p==0 || p==&((u8 *)pFd->pMapRegion)[iOff] );
+
+  if( p ){
+    pFd->nFetchOut--;
+  }else{
+    unixUnmapfile(pFd);
+  }
+
+  assert( pFd->nFetchOut>=0 );
+#else
+  UNUSED_PARAMETER(fd);
+  UNUSED_PARAMETER(p);
+  UNUSED_PARAMETER(iOff);
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Here ends the implementation of all sqlite3_file methods.
+**
+********************** End sqlite3_file Methods *******************************
+******************************************************************************/
+
+/*
+** This division contains definitions of sqlite3_io_methods objects that
+** implement various file locking strategies.  It also contains definitions
+** of "finder" functions.  A finder-function is used to locate the appropriate
+** sqlite3_io_methods object for a particular database file.  The pAppData
+** field of the sqlite3_vfs VFS objects are initialized to be pointers to
+** the correct finder-function for that VFS.
+**
+** Most finder functions return a pointer to a fixed sqlite3_io_methods
+** object.  The only interesting finder-function is autolockIoFinder, which
+** looks at the filesystem type and tries to guess the best locking
+** strategy from that.
+**
+** For finder-function F, two objects are created:
+**
+**    (1) The real finder-function named "FImpt()".
+**
+**    (2) A constant pointer to this function named just "F".
+**
+**
+** A pointer to the F pointer is used as the pAppData value for VFS
+** objects.  We have to do this instead of letting pAppData point
+** directly at the finder-function since C90 rules prevent a void*
+** from be cast into a function pointer.
+**
+**
+** Each instance of this macro generates two objects:
+**
+**   *  A constant sqlite3_io_methods object call METHOD that has locking
+**      methods CLOSE, LOCK, UNLOCK, CKRESLOCK.
+**
+**   *  An I/O method finder function called FINDER that returns a pointer
+**      to the METHOD object in the previous bullet.
+*/
+#define IOMETHODS(FINDER,METHOD,VERSION,CLOSE,LOCK,UNLOCK,CKLOCK,SHMMAP)     \
+static const sqlite3_io_methods METHOD = {                                   \
+   VERSION,                    /* iVersion */                                \
+   CLOSE,                      /* xClose */                                  \
+   unixRead,                   /* xRead */                                   \
+   unixWrite,                  /* xWrite */                                  \
+   unixTruncate,               /* xTruncate */                               \
+   unixSync,                   /* xSync */                                   \
+   unixFileSize,               /* xFileSize */                               \
+   LOCK,                       /* xLock */                                   \
+   UNLOCK,                     /* xUnlock */                                 \
+   CKLOCK,                     /* xCheckReservedLock */                      \
+   unixFileControl,            /* xFileControl */                            \
+   unixSectorSize,             /* xSectorSize */                             \
+   unixDeviceCharacteristics,  /* xDeviceCapabilities */                     \
+   SHMMAP,                     /* xShmMap */                                 \
+   unixShmLock,                /* xShmLock */                                \
+   unixShmBarrier,             /* xShmBarrier */                             \
+   unixShmUnmap,               /* xShmUnmap */                               \
+   unixFetch,                  /* xFetch */                                  \
+   unixUnfetch,                /* xUnfetch */                                \
+};                                                                           \
+static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){   \
+  UNUSED_PARAMETER(z); UNUSED_PARAMETER(p);                                  \
+  return &METHOD;                                                            \
+}                                                                            \
+static const sqlite3_io_methods *(*const FINDER)(const char*,unixFile *p)    \
+    = FINDER##Impl;
+
+/*
+** Here are all of the sqlite3_io_methods objects for each of the
+** locking strategies.  Functions that return pointers to these methods
+** are also created.
+*/
+IOMETHODS(
+  posixIoFinder,            /* Finder function name */
+  posixIoMethods,           /* sqlite3_io_methods object name */
+  3,                        /* shared memory and mmap are enabled */
+  unixClose,                /* xClose method */
+  unixLock,                 /* xLock method */
+  unixUnlock,               /* xUnlock method */
+  unixCheckReservedLock,    /* xCheckReservedLock method */
+  unixShmMap                /* xShmMap method */
+)
+IOMETHODS(
+  nolockIoFinder,           /* Finder function name */
+  nolockIoMethods,          /* sqlite3_io_methods object name */
+  3,                        /* shared memory and mmap are enabled */
+  nolockClose,              /* xClose method */
+  nolockLock,               /* xLock method */
+  nolockUnlock,             /* xUnlock method */
+  nolockCheckReservedLock,  /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+IOMETHODS(
+  dotlockIoFinder,          /* Finder function name */
+  dotlockIoMethods,         /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  dotlockClose,             /* xClose method */
+  dotlockLock,              /* xLock method */
+  dotlockUnlock,            /* xUnlock method */
+  dotlockCheckReservedLock, /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+
+#if SQLITE_ENABLE_LOCKING_STYLE
+IOMETHODS(
+  flockIoFinder,            /* Finder function name */
+  flockIoMethods,           /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  flockClose,               /* xClose method */
+  flockLock,                /* xLock method */
+  flockUnlock,              /* xUnlock method */
+  flockCheckReservedLock,   /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+#endif
+
+#if OS_VXWORKS
+IOMETHODS(
+  semIoFinder,              /* Finder function name */
+  semIoMethods,             /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  semXClose,                /* xClose method */
+  semXLock,                 /* xLock method */
+  semXUnlock,               /* xUnlock method */
+  semXCheckReservedLock,    /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+#endif
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+IOMETHODS(
+  afpIoFinder,              /* Finder function name */
+  afpIoMethods,             /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  afpClose,                 /* xClose method */
+  afpLock,                  /* xLock method */
+  afpUnlock,                /* xUnlock method */
+  afpCheckReservedLock,     /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+#endif
+
+/*
+** The proxy locking method is a "super-method" in the sense that it
+** opens secondary file descriptors for the conch and lock files and
+** it uses proxy, dot-file, AFP, and flock() locking methods on those
+** secondary files.  For this reason, the division that implements
+** proxy locking is located much further down in the file.  But we need
+** to go ahead and define the sqlite3_io_methods and finder function
+** for proxy locking here.  So we forward declare the I/O methods.
+*/
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+static int proxyClose(sqlite3_file*);
+static int proxyLock(sqlite3_file*, int);
+static int proxyUnlock(sqlite3_file*, int);
+static int proxyCheckReservedLock(sqlite3_file*, int*);
+IOMETHODS(
+  proxyIoFinder,            /* Finder function name */
+  proxyIoMethods,           /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  proxyClose,               /* xClose method */
+  proxyLock,                /* xLock method */
+  proxyUnlock,              /* xUnlock method */
+  proxyCheckReservedLock,   /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+#endif
+
+/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+IOMETHODS(
+  nfsIoFinder,               /* Finder function name */
+  nfsIoMethods,              /* sqlite3_io_methods object name */
+  1,                         /* shared memory is disabled */
+  unixClose,                 /* xClose method */
+  unixLock,                  /* xLock method */
+  nfsUnlock,                 /* xUnlock method */
+  unixCheckReservedLock,     /* xCheckReservedLock method */
+  0                          /* xShmMap method */
+)
+#endif
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+/*
+** This "finder" function attempts to determine the best locking strategy
+** for the database file "filePath".  It then returns the sqlite3_io_methods
+** object that implements that strategy.
+**
+** This is for MacOSX only.
+*/
+static const sqlite3_io_methods *autolockIoFinderImpl(
+  const char *filePath,    /* name of the database file */
+  unixFile *pNew           /* open file object for the database file */
+){
+  static const struct Mapping {
+    const char *zFilesystem;              /* Filesystem type name */
+    const sqlite3_io_methods *pMethods;   /* Appropriate locking method */
+  } aMap[] = {
+    { "hfs",    &posixIoMethods },
+    { "ufs",    &posixIoMethods },
+    { "afpfs",  &afpIoMethods },
+    { "smbfs",  &afpIoMethods },
+    { "webdav", &nolockIoMethods },
+    { 0, 0 }
+  };
+  int i;
+  struct statfs fsInfo;
+  struct flock lockInfo;
+
+  if( !filePath ){
+    /* If filePath==NULL that means we are dealing with a transient file
+    ** that does not need to be locked. */
+    return &nolockIoMethods;
+  }
+  if( statfs(filePath, &fsInfo) != -1 ){
+    if( fsInfo.f_flags & MNT_RDONLY ){
+      return &nolockIoMethods;
+    }
+    for(i=0; aMap[i].zFilesystem; i++){
+      if( strcmp(fsInfo.f_fstypename, aMap[i].zFilesystem)==0 ){
+        return aMap[i].pMethods;
+      }
+    }
+  }
+
+  /* Default case. Handles, amongst others, "nfs".
+  ** Test byte-range lock using fcntl(). If the call succeeds,
+  ** assume that the file-system supports POSIX style locks.
+  */
+  lockInfo.l_len = 1;
+  lockInfo.l_start = 0;
+  lockInfo.l_whence = SEEK_SET;
+  lockInfo.l_type = F_RDLCK;
+  if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
+    if( strcmp(fsInfo.f_fstypename, "nfs")==0 ){
+      return &nfsIoMethods;
+    } else {
+      return &posixIoMethods;
+    }
+  }else{
+    return &dotlockIoMethods;
+  }
+}
+static const sqlite3_io_methods
+  *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl;
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+
+#if OS_VXWORKS
+/*
+** This "finder" function for VxWorks checks to see if posix advisory
+** locking works.  If it does, then that is what is used.  If it does not
+** work, then fallback to named semaphore locking.
+*/
+static const sqlite3_io_methods *vxworksIoFinderImpl(
+  const char *filePath,    /* name of the database file */
+  unixFile *pNew           /* the open file object */
+){
+  struct flock lockInfo;
+
+  if( !filePath ){
+    /* If filePath==NULL that means we are dealing with a transient file
+    ** that does not need to be locked. */
+    return &nolockIoMethods;
+  }
+
+  /* Test if fcntl() is supported and use POSIX style locks.
+  ** Otherwise fall back to the named semaphore method.
+  */
+  lockInfo.l_len = 1;
+  lockInfo.l_start = 0;
+  lockInfo.l_whence = SEEK_SET;
+  lockInfo.l_type = F_RDLCK;
+  if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
+    return &posixIoMethods;
+  }else{
+    return &semIoMethods;
+  }
+}
+static const sqlite3_io_methods
+  *(*const vxworksIoFinder)(const char*,unixFile*) = vxworksIoFinderImpl;
+
+#endif /* OS_VXWORKS */
+
+/*
+** An abstract type for a pointer to an IO method finder function:
+*/
+typedef const sqlite3_io_methods *(*finder_type)(const char*,unixFile*);
+
+
+/****************************************************************************
+**************************** sqlite3_vfs methods ****************************
+**
+** This division contains the implementation of methods on the
+** sqlite3_vfs object.
+*/
+
+/*
+** Initialize the contents of the unixFile structure pointed to by pId.
+*/
+static int fillInUnixFile(
+  sqlite3_vfs *pVfs,      /* Pointer to vfs object */
+  int h,                  /* Open file descriptor of file being opened */
+  sqlite3_file *pId,      /* Write to the unixFile structure here */
+  const char *zFilename,  /* Name of the file being opened */
+  int ctrlFlags           /* Zero or more UNIXFILE_* values */
+){
+  const sqlite3_io_methods *pLockingStyle;
+  unixFile *pNew = (unixFile *)pId;
+  int rc = SQLITE_OK;
+
+  assert( pNew->pInode==NULL );
+
+  /* No locking occurs in temporary files */
+  assert( zFilename!=0 || (ctrlFlags & UNIXFILE_NOLOCK)!=0 );
+
+  OSTRACE(("OPEN    %-3d %s\n", h, zFilename));
+  pNew->h = h;
+  pNew->pVfs = pVfs;
+  pNew->zPath = zFilename;
+  pNew->ctrlFlags = (u8)ctrlFlags;
+#if SQLITE_MAX_MMAP_SIZE>0
+  pNew->mmapSizeMax = sqlite3GlobalConfig.szMmap;
+#endif
+  if( sqlite3_uri_boolean(((ctrlFlags & UNIXFILE_URI) ? zFilename : 0),
+                           "psow", SQLITE_POWERSAFE_OVERWRITE) ){
+    pNew->ctrlFlags |= UNIXFILE_PSOW;
+  }
+  if( strcmp(pVfs->zName,"unix-excl")==0 ){
+    pNew->ctrlFlags |= UNIXFILE_EXCL;
+  }
+
+#if OS_VXWORKS
+  pNew->pId = vxworksFindFileId(zFilename);
+  if( pNew->pId==0 ){
+    ctrlFlags |= UNIXFILE_NOLOCK;
+    rc = SQLITE_NOMEM_BKPT;
+  }
+#endif
+
+  if( ctrlFlags & UNIXFILE_NOLOCK ){
+    pLockingStyle = &nolockIoMethods;
+  }else{
+    pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew);
+#if SQLITE_ENABLE_LOCKING_STYLE
+    /* Cache zFilename in the locking context (AFP and dotlock override) for
+    ** proxyLock activation is possible (remote proxy is based on db name)
+    ** zFilename remains valid until file is closed, to support */
+    pNew->lockingContext = (void*)zFilename;
+#endif
+  }
+
+  if( pLockingStyle == &posixIoMethods
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+    || pLockingStyle == &nfsIoMethods
+#endif
+  ){
+    unixEnterMutex();
+    rc = findInodeInfo(pNew, &pNew->pInode);
+    if( rc!=SQLITE_OK ){
+      /* If an error occurred in findInodeInfo(), close the file descriptor
+      ** immediately, before releasing the mutex. findInodeInfo() may fail
+      ** in two scenarios:
+      **
+      **   (a) A call to fstat() failed.
+      **   (b) A malloc failed.
+      **
+      ** Scenario (b) may only occur if the process is holding no other
+      ** file descriptors open on the same file. If there were other file
+      ** descriptors on this file, then no malloc would be required by
+      ** findInodeInfo(). If this is the case, it is quite safe to close
+      ** handle h - as it is guaranteed that no posix locks will be released
+      ** by doing so.
+      **
+      ** If scenario (a) caused the error then things are not so safe. The
+      ** implicit assumption here is that if fstat() fails, things are in
+      ** such bad shape that dropping a lock or two doesn't matter much.
+      */
+      robust_close(pNew, h, __LINE__);
+      h = -1;
+    }
+    unixLeaveMutex();
+  }
+
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+  else if( pLockingStyle == &afpIoMethods ){
+    /* AFP locking uses the file path so it needs to be included in
+    ** the afpLockingContext.
+    */
+    afpLockingContext *pCtx;
+    pNew->lockingContext = pCtx = sqlite3_malloc64( sizeof(*pCtx) );
+    if( pCtx==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      /* NB: zFilename exists and remains valid until the file is closed
+      ** according to requirement F11141.  So we do not need to make a
+      ** copy of the filename. */
+      pCtx->dbPath = zFilename;
+      pCtx->reserved = 0;
+      srandomdev();
+      unixEnterMutex();
+      rc = findInodeInfo(pNew, &pNew->pInode);
+      if( rc!=SQLITE_OK ){
+        sqlite3_free(pNew->lockingContext);
+        robust_close(pNew, h, __LINE__);
+        h = -1;
+      }
+      unixLeaveMutex();
+    }
+  }
+#endif
+
+  else if( pLockingStyle == &dotlockIoMethods ){
+    /* Dotfile locking uses the file path so it needs to be included in
+    ** the dotlockLockingContext
+    */
+    char *zLockFile;
+    int nFilename;
+    assert( zFilename!=0 );
+    nFilename = (int)strlen(zFilename) + 6;
+    zLockFile = (char *)sqlite3_malloc64(nFilename);
+    if( zLockFile==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      sqlite3_snprintf(nFilename, zLockFile, "%s" DOTLOCK_SUFFIX, zFilename);
+    }
+    pNew->lockingContext = zLockFile;
+  }
+
+#if OS_VXWORKS
+  else if( pLockingStyle == &semIoMethods ){
+    /* Named semaphore locking uses the file path so it needs to be
+    ** included in the semLockingContext
+    */
+    unixEnterMutex();
+    rc = findInodeInfo(pNew, &pNew->pInode);
+    if( (rc==SQLITE_OK) && (pNew->pInode->pSem==NULL) ){
+      char *zSemName = pNew->pInode->aSemName;
+      int n;
+      sqlite3_snprintf(MAX_PATHNAME, zSemName, "/%s.sem",
+                       pNew->pId->zCanonicalName);
+      for( n=1; zSemName[n]; n++ )
+        if( zSemName[n]=='/' ) zSemName[n] = '_';
+      pNew->pInode->pSem = sem_open(zSemName, O_CREAT, 0666, 1);
+      if( pNew->pInode->pSem == SEM_FAILED ){
+        rc = SQLITE_NOMEM_BKPT;
+        pNew->pInode->aSemName[0] = '\0';
+      }
+    }
+    unixLeaveMutex();
+  }
+#endif
+
+  storeLastErrno(pNew, 0);
+#if OS_VXWORKS
+  if( rc!=SQLITE_OK ){
+    if( h>=0 ) robust_close(pNew, h, __LINE__);
+    h = -1;
+    osUnlink(zFilename);
+    pNew->ctrlFlags |= UNIXFILE_DELETE;
+  }
+#endif
+  if( rc!=SQLITE_OK ){
+    if( h>=0 ) robust_close(pNew, h, __LINE__);
+  }else{
+    pId->pMethods = pLockingStyle;
+    OpenCounter(+1);
+    verifyDbFile(pNew);
+  }
+  return rc;
+}
+
+/*
+** Directories to consider for temp files.
+*/
+static const char *azTempDirs[] = {
+  0,
+  0,
+  "/var/tmp",
+  "/usr/tmp",
+  "/tmp",
+  "."
+};
+
+/*
+** Initialize first two members of azTempDirs[] array.
+*/
+static void unixTempFileInit(void){
+  azTempDirs[0] = getenv("SQLITE_TMPDIR");
+  azTempDirs[1] = getenv("TMPDIR");
+}
+
+/*
+** Return the name of a directory in which to put temporary files.
+** If no suitable temporary file directory can be found, return NULL.
+*/
+static const char *unixTempFileDir(void){
+  unsigned int i = 0;
+  struct stat buf;
+  const char *zDir = sqlite3_temp_directory;
+
+  while(1){
+    if( zDir!=0
+     && osStat(zDir, &buf)==0
+     && S_ISDIR(buf.st_mode)
+     && osAccess(zDir, 03)==0
+    ){
+      return zDir;
+    }
+    if( i>=sizeof(azTempDirs)/sizeof(azTempDirs[0]) ) break;
+    zDir = azTempDirs[i++];
+  }
+  return 0;
+}
+
+/*
+** Create a temporary file name in zBuf.  zBuf must be allocated
+** by the calling process and must be big enough to hold at least
+** pVfs->mxPathname bytes.
+*/
+static int unixGetTempname(int nBuf, char *zBuf){
+  const char *zDir;
+  int iLimit = 0;
+  int rc = SQLITE_OK;
+
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing.
+  */
+  zBuf[0] = 0;
+  SimulateIOError( return SQLITE_IOERR );
+
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  zDir = unixTempFileDir();
+  if( zDir==0 ){
+    rc = SQLITE_IOERR_GETTEMPPATH;
+  }else{
+    do{
+      u64 r;
+      sqlite3_randomness(sizeof(r), &r);
+      assert( nBuf>2 );
+      zBuf[nBuf-2] = 0;
+      sqlite3_snprintf(nBuf, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX"%llx%c",
+                       zDir, r, 0);
+      if( zBuf[nBuf-2]!=0 || (iLimit++)>10 ){
+        rc = SQLITE_ERROR;
+        break;
+      }
+    }while( osAccess(zBuf,0)==0 );
+  }
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return rc;
+}
+
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+/*
+** Routine to transform a unixFile into a proxy-locking unixFile.
+** Implementation in the proxy-lock division, but used by unixOpen()
+** if SQLITE_PREFER_PROXY_LOCKING is defined.
+*/
+static int proxyTransformUnixFile(unixFile*, const char*);
+#endif
+
+/*
+** Search for an unused file descriptor that was opened on the database
+** file (not a journal or super-journal file) identified by pathname
+** zPath with SQLITE_OPEN_XXX flags matching those passed as the second
+** argument to this function.
+**
+** Such a file descriptor may exist if a database connection was closed
+** but the associated file descriptor could not be closed because some
+** other file descriptor open on the same file is holding a file-lock.
+** Refer to comments in the unixClose() function and the lengthy comment
+** describing "Posix Advisory Locking" at the start of this file for
+** further details. Also, ticket #4018.
+**
+** If a suitable file descriptor is found, then it is returned. If no
+** such file descriptor is located, -1 is returned.
+*/
+static UnixUnusedFd *findReusableFd(const char *zPath, int flags){
+  UnixUnusedFd *pUnused = 0;
+
+  /* Do not search for an unused file descriptor on vxworks. Not because
+  ** vxworks would not benefit from the change (it might, we're not sure),
+  ** but because no way to test it is currently available. It is better
+  ** not to risk breaking vxworks support for the sake of such an obscure
+  ** feature.  */
+#if !OS_VXWORKS
+  struct stat sStat;                   /* Results of stat() call */
+
+  unixEnterMutex();
+
+  /* A stat() call may fail for various reasons. If this happens, it is
+  ** almost certain that an open() call on the same path will also fail.
+  ** For this reason, if an error occurs in the stat() call here, it is
+  ** ignored and -1 is returned. The caller will try to open a new file
+  ** descriptor on the same path, fail, and return an error to SQLite.
+  **
+  ** Even if a subsequent open() call does succeed, the consequences of
+  ** not searching for a reusable file descriptor are not dire.  */
+  if( inodeList!=0 && 0==osStat(zPath, &sStat) ){
+    unixInodeInfo *pInode;
+
+    pInode = inodeList;
+    while( pInode && (pInode->fileId.dev!=sStat.st_dev
+                     || pInode->fileId.ino!=(u64)sStat.st_ino) ){
+       pInode = pInode->pNext;
+    }
+    if( pInode ){
+      UnixUnusedFd **pp;
+      assert( sqlite3_mutex_notheld(pInode->pLockMutex) );
+      sqlite3_mutex_enter(pInode->pLockMutex);
+      flags &= (SQLITE_OPEN_READONLY|SQLITE_OPEN_READWRITE);
+      for(pp=&pInode->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext));
+      pUnused = *pp;
+      if( pUnused ){
+        *pp = pUnused->pNext;
+      }
+      sqlite3_mutex_leave(pInode->pLockMutex);
+    }
+  }
+  unixLeaveMutex();
+#endif    /* if !OS_VXWORKS */
+  return pUnused;
+}
+
+/*
+** Find the mode, uid and gid of file zFile.
+*/
+static int getFileMode(
+  const char *zFile,              /* File name */
+  mode_t *pMode,                  /* OUT: Permissions of zFile */
+  uid_t *pUid,                    /* OUT: uid of zFile. */
+  gid_t *pGid                     /* OUT: gid of zFile. */
+){
+  struct stat sStat;              /* Output of stat() on database file */
+  int rc = SQLITE_OK;
+  if( 0==osStat(zFile, &sStat) ){
+    *pMode = sStat.st_mode & 0777;
+    *pUid = sStat.st_uid;
+    *pGid = sStat.st_gid;
+  }else{
+    rc = SQLITE_IOERR_FSTAT;
+  }
+  return rc;
+}
+
+/*
+** This function is called by unixOpen() to determine the unix permissions
+** to create new files with. If no error occurs, then SQLITE_OK is returned
+** and a value suitable for passing as the third argument to open(2) is
+** written to *pMode. If an IO error occurs, an SQLite error code is
+** returned and the value of *pMode is not modified.
+**
+** In most cases, this routine sets *pMode to 0, which will become
+** an indication to robust_open() to create the file using
+** SQLITE_DEFAULT_FILE_PERMISSIONS adjusted by the umask.
+** But if the file being opened is a WAL or regular journal file, then
+** this function queries the file-system for the permissions on the
+** corresponding database file and sets *pMode to this value. Whenever
+** possible, WAL and journal files are created using the same permissions
+** as the associated database file.
+**
+** If the SQLITE_ENABLE_8_3_NAMES option is enabled, then the
+** original filename is unavailable.  But 8_3_NAMES is only used for
+** FAT filesystems and permissions do not matter there, so just use
+** the default permissions.  In 8_3_NAMES mode, leave *pMode set to zero.
+*/
+static int findCreateFileMode(
+  const char *zPath,              /* Path of file (possibly) being created */
+  int flags,                      /* Flags passed as 4th argument to xOpen() */
+  mode_t *pMode,                  /* OUT: Permissions to open file with */
+  uid_t *pUid,                    /* OUT: uid to set on the file */
+  gid_t *pGid                     /* OUT: gid to set on the file */
+){
+  int rc = SQLITE_OK;             /* Return Code */
+  *pMode = 0;
+  *pUid = 0;
+  *pGid = 0;
+  if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){
+    char zDb[MAX_PATHNAME+1];     /* Database file path */
+    int nDb;                      /* Number of valid bytes in zDb */
+
+    /* zPath is a path to a WAL or journal file. The following block derives
+    ** the path to the associated database file from zPath. This block handles
+    ** the following naming conventions:
+    **
+    **   "<path to db>-journal"
+    **   "<path to db>-wal"
+    **   "<path to db>-journalNN"
+    **   "<path to db>-walNN"
+    **
+    ** where NN is a decimal number. The NN naming schemes are
+    ** used by the test_multiplex.c module.
+    **
+    ** In normal operation, the journal file name will always contain
+    ** a '-' character.  However in 8+3 filename mode, or if a corrupt
+    ** rollback journal specifies a super-journal with a goofy name, then
+    ** the '-' might be missing or the '-' might be the first character in
+    ** the filename.  In that case, just return SQLITE_OK with *pMode==0.
+    */
+    nDb = sqlite3Strlen30(zPath) - 1;
+    while( nDb>0 && zPath[nDb]!='.' ){
+      if( zPath[nDb]=='-' ){
+        memcpy(zDb, zPath, nDb);
+        zDb[nDb] = '\0';
+        rc = getFileMode(zDb, pMode, pUid, pGid);
+        break;
+      }
+      nDb--;
+    }
+  }else if( flags & SQLITE_OPEN_DELETEONCLOSE ){
+    *pMode = 0600;
+  }else if( flags & SQLITE_OPEN_URI ){
+    /* If this is a main database file and the file was opened using a URI
+    ** filename, check for the "modeof" parameter. If present, interpret
+    ** its value as a filename and try to copy the mode, uid and gid from
+    ** that file.  */
+    const char *z = sqlite3_uri_parameter(zPath, "modeof");
+    if( z ){
+      rc = getFileMode(z, pMode, pUid, pGid);
+    }
+  }
+  return rc;
+}
+
+/*
+** Open the file zPath.
+**
+** Previously, the SQLite OS layer used three functions in place of this
+** one:
+**
+**     sqlite3OsOpenReadWrite();
+**     sqlite3OsOpenReadOnly();
+**     sqlite3OsOpenExclusive();
+**
+** These calls correspond to the following combinations of flags:
+**
+**     ReadWrite() ->     (READWRITE | CREATE)
+**     ReadOnly()  ->     (READONLY)
+**     OpenExclusive() -> (READWRITE | CREATE | EXCLUSIVE)
+**
+** The old OpenExclusive() accepted a boolean argument - "delFlag". If
+** true, the file was configured to be automatically deleted when the
+** file handle closed. To achieve the same effect using this new
+** interface, add the DELETEONCLOSE flag to those specified above for
+** OpenExclusive().
+*/
+static int unixOpen(
+  sqlite3_vfs *pVfs,           /* The VFS for which this is the xOpen method */
+  const char *zPath,           /* Pathname of file to be opened */
+  sqlite3_file *pFile,         /* The file descriptor to be filled in */
+  int flags,                   /* Input flags to control the opening */
+  int *pOutFlags               /* Output flags returned to SQLite core */
+){
+  unixFile *p = (unixFile *)pFile;
+  int fd = -1;                   /* File descriptor returned by open() */
+  int openFlags = 0;             /* Flags to pass to open() */
+  int eType = flags&0x0FFF00;  /* Type of file to open */
+  int noLock;                    /* True to omit locking primitives */
+  int rc = SQLITE_OK;            /* Function Return Code */
+  int ctrlFlags = 0;             /* UNIXFILE_* flags */
+
+  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
+  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
+  int isCreate     = (flags & SQLITE_OPEN_CREATE);
+  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
+  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
+#if SQLITE_ENABLE_LOCKING_STYLE
+  int isAutoProxy  = (flags & SQLITE_OPEN_AUTOPROXY);
+#endif
+#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
+  struct statfs fsInfo;
+#endif
+
+  /* If creating a super- or main-file journal, this function will open
+  ** a file-descriptor on the directory too. The first time unixSync()
+  ** is called the directory file descriptor will be fsync()ed and close()d.
+  */
+  int isNewJrnl = (isCreate && (
+        eType==SQLITE_OPEN_SUPER_JOURNAL
+     || eType==SQLITE_OPEN_MAIN_JOURNAL
+     || eType==SQLITE_OPEN_WAL
+  ));
+
+  /* If argument zPath is a NULL pointer, this function is required to open
+  ** a temporary file. Use this buffer to store the file name in.
+  */
+  char zTmpname[MAX_PATHNAME+2];
+  const char *zName = zPath;
+
+  /* Check the following statements are true:
+  **
+  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and
+  **   (b) if CREATE is set, then READWRITE must also be set, and
+  **   (c) if EXCLUSIVE is set, then CREATE must also be set.
+  **   (d) if DELETEONCLOSE is set, then CREATE must also be set.
+  */
+  assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly));
+  assert(isCreate==0 || isReadWrite);
+  assert(isExclusive==0 || isCreate);
+  assert(isDelete==0 || isCreate);
+
+  /* The main DB, main journal, WAL file and super-journal are never
+  ** automatically deleted. Nor are they ever temporary files.  */
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_DB );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_SUPER_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_WAL );
+
+  /* Assert that the upper layer has set one of the "file-type" flags. */
+  assert( eType==SQLITE_OPEN_MAIN_DB      || eType==SQLITE_OPEN_TEMP_DB
+       || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL
+       || eType==SQLITE_OPEN_SUBJOURNAL   || eType==SQLITE_OPEN_SUPER_JOURNAL
+       || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL
+  );
+
+  /* Detect a pid change and reset the PRNG.  There is a race condition
+  ** here such that two or more threads all trying to open databases at
+  ** the same instant might all reset the PRNG.  But multiple resets
+  ** are harmless.
+  */
+  if( randomnessPid!=osGetpid(0) ){
+    randomnessPid = osGetpid(0);
+    sqlite3_randomness(0,0);
+  }
+  memset(p, 0, sizeof(unixFile));
+
+#ifdef SQLITE_ASSERT_NO_FILES
+  /* Applications that never read or write a persistent disk files */
+  assert( zName==0 );
+#endif
+
+  if( eType==SQLITE_OPEN_MAIN_DB ){
+    UnixUnusedFd *pUnused;
+    pUnused = findReusableFd(zName, flags);
+    if( pUnused ){
+      fd = pUnused->fd;
+    }else{
+      pUnused = sqlite3_malloc64(sizeof(*pUnused));
+      if( !pUnused ){
+        return SQLITE_NOMEM_BKPT;
+      }
+    }
+    p->pPreallocatedUnused = pUnused;
+
+    /* Database filenames are double-zero terminated if they are not
+    ** URIs with parameters.  Hence, they can always be passed into
+    ** sqlite3_uri_parameter(). */
+    assert( (flags & SQLITE_OPEN_URI) || zName[strlen(zName)+1]==0 );
+
+  }else if( !zName ){
+    /* If zName is NULL, the upper layer is requesting a temp file. */
+    assert(isDelete && !isNewJrnl);
+    rc = unixGetTempname(pVfs->mxPathname, zTmpname);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    zName = zTmpname;
+
+    /* Generated temporary filenames are always double-zero terminated
+    ** for use by sqlite3_uri_parameter(). */
+    assert( zName[strlen(zName)+1]==0 );
+  }
+
+  /* Determine the value of the flags parameter passed to POSIX function
+  ** open(). These must be calculated even if open() is not called, as
+  ** they may be stored as part of the file handle and used by the
+  ** 'conch file' locking functions later on.  */
+  if( isReadonly )  openFlags |= O_RDONLY;
+  if( isReadWrite ) openFlags |= O_RDWR;
+  if( isCreate )    openFlags |= O_CREAT;
+  if( isExclusive ) openFlags |= (O_EXCL|O_NOFOLLOW);
+  openFlags |= (O_LARGEFILE|O_BINARY|O_NOFOLLOW);
+
+  if( fd<0 ){
+    mode_t openMode;              /* Permissions to create file with */
+    uid_t uid;                    /* Userid for the file */
+    gid_t gid;                    /* Groupid for the file */
+    rc = findCreateFileMode(zName, flags, &openMode, &uid, &gid);
+    if( rc!=SQLITE_OK ){
+      assert( !p->pPreallocatedUnused );
+      assert( eType==SQLITE_OPEN_WAL || eType==SQLITE_OPEN_MAIN_JOURNAL );
+      return rc;
+    }
+    fd = robust_open(zName, openFlags, openMode);
+    OSTRACE(("OPENX   %-3d %s 0%o\n", fd, zName, openFlags));
+    assert( !isExclusive || (openFlags & O_CREAT)!=0 );
+    if( fd<0 ){
+      if( isNewJrnl && errno==EACCES && osAccess(zName, F_OK) ){
+        /* If unable to create a journal because the directory is not
+        ** writable, change the error code to indicate that. */
+        rc = SQLITE_READONLY_DIRECTORY;
+      }else if( errno!=EISDIR && isReadWrite ){
+        /* Failed to open the file for read/write access. Try read-only. */
+        UnixUnusedFd *pReadonly = 0;
+        flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
+        openFlags &= ~(O_RDWR|O_CREAT);
+        flags |= SQLITE_OPEN_READONLY;
+        openFlags |= O_RDONLY;
+        isReadonly = 1;
+        pReadonly = findReusableFd(zName, flags);
+        if( pReadonly ){
+          fd = pReadonly->fd;
+          sqlite3_free(pReadonly);
+        }else{
+          fd = robust_open(zName, openFlags, openMode);
+        }
+      }
+    }
+    if( fd<0 ){
+      int rc2 = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zName);
+      if( rc==SQLITE_OK ) rc = rc2;
+      goto open_finished;
+    }
+
+    /* The owner of the rollback journal or WAL file should always be the
+    ** same as the owner of the database file.  Try to ensure that this is
+    ** the case.  The chown() system call will be a no-op if the current
+    ** process lacks root privileges, be we should at least try.  Without
+    ** this step, if a root process opens a database file, it can leave
+    ** behinds a journal/WAL that is owned by root and hence make the
+    ** database inaccessible to unprivileged processes.
+    **
+    ** If openMode==0, then that means uid and gid are not set correctly
+    ** (probably because SQLite is configured to use 8+3 filename mode) and
+    ** in that case we do not want to attempt the chown().
+    */
+    if( openMode && (flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL))!=0 ){
+      robustFchown(fd, uid, gid);
+    }
+  }
+  assert( fd>=0 );
+  if( pOutFlags ){
+    *pOutFlags = flags;
+  }
+
+  if( p->pPreallocatedUnused ){
+    p->pPreallocatedUnused->fd = fd;
+    p->pPreallocatedUnused->flags =
+                          flags & (SQLITE_OPEN_READONLY|SQLITE_OPEN_READWRITE);
+  }
+
+  if( isDelete ){
+#if OS_VXWORKS
+    zPath = zName;
+#elif defined(SQLITE_UNLINK_AFTER_CLOSE)
+    zPath = sqlite3_mprintf("%s", zName);
+    if( zPath==0 ){
+      robust_close(p, fd, __LINE__);
+      return SQLITE_NOMEM_BKPT;
+    }
+#else
+    osUnlink(zName);
+#endif
+  }
+#if SQLITE_ENABLE_LOCKING_STYLE
+  else{
+    p->openFlags = openFlags;
+  }
+#endif
+
+#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
+  if( fstatfs(fd, &fsInfo) == -1 ){
+    storeLastErrno(p, errno);
+    robust_close(p, fd, __LINE__);
+    return SQLITE_IOERR_ACCESS;
+  }
+  if (0 == strncmp("msdos", fsInfo.f_fstypename, 5)) {
+    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
+  }
+  if (0 == strncmp("exfat", fsInfo.f_fstypename, 5)) {
+    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
+  }
+#endif
+
+  /* Set up appropriate ctrlFlags */
+  if( isDelete )                ctrlFlags |= UNIXFILE_DELETE;
+  if( isReadonly )              ctrlFlags |= UNIXFILE_RDONLY;
+  noLock = eType!=SQLITE_OPEN_MAIN_DB;
+  if( noLock )                  ctrlFlags |= UNIXFILE_NOLOCK;
+  if( isNewJrnl )               ctrlFlags |= UNIXFILE_DIRSYNC;
+  if( flags & SQLITE_OPEN_URI ) ctrlFlags |= UNIXFILE_URI;
+
+#if SQLITE_ENABLE_LOCKING_STYLE
+#if SQLITE_PREFER_PROXY_LOCKING
+  isAutoProxy = 1;
+#endif
+  if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){
+    char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING");
+    int useProxy = 0;
+
+    /* SQLITE_FORCE_PROXY_LOCKING==1 means force always use proxy, 0 means
+    ** never use proxy, NULL means use proxy for non-local files only.  */
+    if( envforce!=NULL ){
+      useProxy = atoi(envforce)>0;
+    }else{
+      useProxy = !(fsInfo.f_flags&MNT_LOCAL);
+    }
+    if( useProxy ){
+      rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);
+      if( rc==SQLITE_OK ){
+        rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:");
+        if( rc!=SQLITE_OK ){
+          /* Use unixClose to clean up the resources added in fillInUnixFile
+          ** and clear all the structure's references.  Specifically,
+          ** pFile->pMethods will be NULL so sqlite3OsClose will be a no-op
+          */
+          unixClose(pFile);
+          return rc;
+        }
+      }
+      goto open_finished;
+    }
+  }
+#endif
+
+  assert( zPath==0 || zPath[0]=='/'
+      || eType==SQLITE_OPEN_SUPER_JOURNAL || eType==SQLITE_OPEN_MAIN_JOURNAL
+  );
+  rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);
+
+open_finished:
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(p->pPreallocatedUnused);
+  }
+  return rc;
+}
+
+
+/*
+** Delete the file at zPath. If the dirSync argument is true, fsync()
+** the directory after deleting the file.
+*/
+static int unixDelete(
+  sqlite3_vfs *NotUsed,     /* VFS containing this as the xDelete method */
+  const char *zPath,        /* Name of file to be deleted */
+  int dirSync               /* If true, fsync() directory after deleting file */
+){
+  int rc = SQLITE_OK;
+  UNUSED_PARAMETER(NotUsed);
+  SimulateIOError(return SQLITE_IOERR_DELETE);
+  if( osUnlink(zPath)==(-1) ){
+    if( errno==ENOENT
+#if OS_VXWORKS
+        || osAccess(zPath,0)!=0
+#endif
+    ){
+      rc = SQLITE_IOERR_DELETE_NOENT;
+    }else{
+      rc = unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
+    }
+    return rc;
+  }
+#ifndef SQLITE_DISABLE_DIRSYNC
+  if( (dirSync & 1)!=0 ){
+    int fd;
+    rc = osOpenDirectory(zPath, &fd);
+    if( rc==SQLITE_OK ){
+      if( full_fsync(fd,0,0) ){
+        rc = unixLogError(SQLITE_IOERR_DIR_FSYNC, "fsync", zPath);
+      }
+      robust_close(0, fd, __LINE__);
+    }else{
+      assert( rc==SQLITE_CANTOPEN );
+      rc = SQLITE_OK;
+    }
+  }
+#endif
+  return rc;
+}
+
+/*
+** Test the existence of or access permissions of file zPath. The
+** test performed depends on the value of flags:
+**
+**     SQLITE_ACCESS_EXISTS: Return 1 if the file exists
+**     SQLITE_ACCESS_READWRITE: Return 1 if the file is read and writable.
+**     SQLITE_ACCESS_READONLY: Return 1 if the file is readable.
+**
+** Otherwise return 0.
+*/
+static int unixAccess(
+  sqlite3_vfs *NotUsed,   /* The VFS containing this xAccess method */
+  const char *zPath,      /* Path of the file to examine */
+  int flags,              /* What do we want to learn about the zPath file? */
+  int *pResOut            /* Write result boolean here */
+){
+  UNUSED_PARAMETER(NotUsed);
+  SimulateIOError( return SQLITE_IOERR_ACCESS; );
+  assert( pResOut!=0 );
+
+  /* The spec says there are three possible values for flags.  But only
+  ** two of them are actually used */
+  assert( flags==SQLITE_ACCESS_EXISTS || flags==SQLITE_ACCESS_READWRITE );
+
+  if( flags==SQLITE_ACCESS_EXISTS ){
+    struct stat buf;
+    *pResOut = 0==osStat(zPath, &buf) &&
+                (!S_ISREG(buf.st_mode) || buf.st_size>0);
+  }else{
+    *pResOut = osAccess(zPath, W_OK|R_OK)==0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** A pathname under construction
+*/
+typedef struct DbPath DbPath;
+struct DbPath {
+  int rc;           /* Non-zero following any error */
+  int nSymlink;     /* Number of symlinks resolved */
+  char *zOut;       /* Write the pathname here */
+  int nOut;         /* Bytes of space available to zOut[] */
+  int nUsed;        /* Bytes of zOut[] currently being used */
+};
+
+/* Forward reference */
+static void appendAllPathElements(DbPath*,const char*);
+
+/*
+** Append a single path element to the DbPath under construction
+*/
+static void appendOnePathElement(
+  DbPath *pPath,       /* Path under construction, to which to append zName */
+  const char *zName,   /* Name to append to pPath.  Not zero-terminated */
+  int nName            /* Number of significant bytes in zName */
+){
+  assert( nName>0 );
+  assert( zName!=0 );
+  if( zName[0]=='.' ){
+    if( nName==1 ) return;
+    if( zName[1]=='.' && nName==2 ){
+      if( pPath->nUsed>1 ){
+        assert( pPath->zOut[0]=='/' );
+        while( pPath->zOut[--pPath->nUsed]!='/' ){}
+      }
+      return;
+    }
+  }
+  if( pPath->nUsed + nName + 2 >= pPath->nOut ){
+    pPath->rc = SQLITE_ERROR;
+    return;
+  }
+  pPath->zOut[pPath->nUsed++] = '/';
+  memcpy(&pPath->zOut[pPath->nUsed], zName, nName);
+  pPath->nUsed += nName;
+#if defined(HAVE_READLINK) && defined(HAVE_LSTAT)
+  if( pPath->rc==SQLITE_OK ){
+    const char *zIn;
+    struct stat buf;
+    pPath->zOut[pPath->nUsed] = 0;
+    zIn = pPath->zOut;
+    if( osLstat(zIn, &buf)!=0 ){
+      if( errno!=ENOENT ){
+        pPath->rc = unixLogError(SQLITE_CANTOPEN_BKPT, "lstat", zIn);
+      }
+    }else if( S_ISLNK(buf.st_mode) ){
+      ssize_t got;
+      char zLnk[SQLITE_MAX_PATHLEN+2];
+      if( pPath->nSymlink++ > SQLITE_MAX_SYMLINK ){
+        pPath->rc = SQLITE_CANTOPEN_BKPT;
+        return;
+      }
+      got = osReadlink(zIn, zLnk, sizeof(zLnk)-2);
+      if( got<=0 || got>=(ssize_t)sizeof(zLnk)-2 ){
+        pPath->rc = unixLogError(SQLITE_CANTOPEN_BKPT, "readlink", zIn);
+        return;
+      }
+      zLnk[got] = 0;
+      if( zLnk[0]=='/' ){
+        pPath->nUsed = 0;
+      }else{
+        pPath->nUsed -= nName + 1;
+      }
+      appendAllPathElements(pPath, zLnk);
+    }
+  }
+#endif
+}
+
+/*
+** Append all path elements in zPath to the DbPath under construction.
+*/
+static void appendAllPathElements(
+  DbPath *pPath,       /* Path under construction, to which to append zName */
+  const char *zPath    /* Path to append to pPath.  Is zero-terminated */
+){
+  int i = 0;
+  int j = 0;
+  do{
+    while( zPath[i] && zPath[i]!='/' ){ i++; }
+    if( i>j ){
+      appendOnePathElement(pPath, &zPath[j], i-j);
+    }
+    j = i+1;
+  }while( zPath[i++] );
+}
+
+/*
+** Turn a relative pathname into a full pathname. The relative path
+** is stored as a nul-terminated string in the buffer pointed to by
+** zPath.
+**
+** zOut points to a buffer of at least sqlite3_vfs.mxPathname bytes
+** (in this case, MAX_PATHNAME bytes). The full-path is written to
+** this buffer before returning.
+*/
+static int unixFullPathname(
+  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
+  const char *zPath,            /* Possibly relative input path */
+  int nOut,                     /* Size of output buffer in bytes */
+  char *zOut                    /* Output buffer */
+){
+  DbPath path;
+  UNUSED_PARAMETER(pVfs);
+  path.rc = 0;
+  path.nUsed = 0;
+  path.nSymlink = 0;
+  path.nOut = nOut;
+  path.zOut = zOut;
+  if( zPath[0]!='/' ){
+    char zPwd[SQLITE_MAX_PATHLEN+2];
+    if( osGetcwd(zPwd, sizeof(zPwd)-2)==0 ){
+      return unixLogError(SQLITE_CANTOPEN_BKPT, "getcwd", zPath);
+    }
+    appendAllPathElements(&path, zPwd);
+  }
+  appendAllPathElements(&path, zPath);
+  zOut[path.nUsed] = 0;
+  if( path.rc || path.nUsed<2 ) return SQLITE_CANTOPEN_BKPT;
+  if( path.nSymlink ) return SQLITE_OK_SYMLINK;
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Interfaces for opening a shared library, finding entry points
+** within the shared library, and closing the shared library.
+*/
+#include <dlfcn.h>
+static void *unixDlOpen(sqlite3_vfs *NotUsed, const char *zFilename){
+  UNUSED_PARAMETER(NotUsed);
+  return dlopen(zFilename, RTLD_NOW | RTLD_GLOBAL);
+}
+
+/*
+** SQLite calls this function immediately after a call to unixDlSym() or
+** unixDlOpen() fails (returns a null pointer). If a more detailed error
+** message is available, it is written to zBufOut. If no error message
+** is available, zBufOut is left unmodified and SQLite uses a default
+** error message.
+*/
+static void unixDlError(sqlite3_vfs *NotUsed, int nBuf, char *zBufOut){
+  const char *zErr;
+  UNUSED_PARAMETER(NotUsed);
+  unixEnterMutex();
+  zErr = dlerror();
+  if( zErr ){
+    sqlite3_snprintf(nBuf, zBufOut, "%s", zErr);
+  }
+  unixLeaveMutex();
+}
+static void (*unixDlSym(sqlite3_vfs *NotUsed, void *p, const char*zSym))(void){
+  /*
+  ** GCC with -pedantic-errors says that C90 does not allow a void* to be
+  ** cast into a pointer to a function.  And yet the library dlsym() routine
+  ** returns a void* which is really a pointer to a function.  So how do we
+  ** use dlsym() with -pedantic-errors?
+  **
+  ** Variable x below is defined to be a pointer to a function taking
+  ** parameters void* and const char* and returning a pointer to a function.
+  ** We initialize x by assigning it a pointer to the dlsym() function.
+  ** (That assignment requires a cast.)  Then we call the function that
+  ** x points to.
+  **
+  ** This work-around is unlikely to work correctly on any system where
+  ** you really cannot cast a function pointer into void*.  But then, on the
+  ** other hand, dlsym() will not work on such a system either, so we have
+  ** not really lost anything.
+  */
+  void (*(*x)(void*,const char*))(void);
+  UNUSED_PARAMETER(NotUsed);
+  x = (void(*(*)(void*,const char*))(void))dlsym;
+  return (*x)(p, zSym);
+}
+static void unixDlClose(sqlite3_vfs *NotUsed, void *pHandle){
+  UNUSED_PARAMETER(NotUsed);
+  dlclose(pHandle);
+}
+#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
+  #define unixDlOpen  0
+  #define unixDlError 0
+  #define unixDlSym   0
+  #define unixDlClose 0
+#endif
+
+/*
+** Write nBuf bytes of random data to the supplied buffer zBuf.
+*/
+static int unixRandomness(sqlite3_vfs *NotUsed, int nBuf, char *zBuf){
+  UNUSED_PARAMETER(NotUsed);
+  assert((size_t)nBuf>=(sizeof(time_t)+sizeof(int)));
+
+  /* We have to initialize zBuf to prevent valgrind from reporting
+  ** errors.  The reports issued by valgrind are incorrect - we would
+  ** prefer that the randomness be increased by making use of the
+  ** uninitialized space in zBuf - but valgrind errors tend to worry
+  ** some users.  Rather than argue, it seems easier just to initialize
+  ** the whole array and silence valgrind, even if that means less randomness
+  ** in the random seed.
+  **
+  ** When testing, initializing zBuf[] to zero is all we do.  That means
+  ** that we always use the same random number sequence.  This makes the
+  ** tests repeatable.
+  */
+  memset(zBuf, 0, nBuf);
+  randomnessPid = osGetpid(0);
+#if !defined(SQLITE_TEST) && !defined(SQLITE_OMIT_RANDOMNESS)
+  {
+    int fd, got;
+    fd = robust_open("/dev/urandom", O_RDONLY, 0);
+    if( fd<0 ){
+      time_t t;
+      time(&t);
+      memcpy(zBuf, &t, sizeof(t));
+      memcpy(&zBuf[sizeof(t)], &randomnessPid, sizeof(randomnessPid));
+      assert( sizeof(t)+sizeof(randomnessPid)<=(size_t)nBuf );
+      nBuf = sizeof(t) + sizeof(randomnessPid);
+    }else{
+      do{ got = osRead(fd, zBuf, nBuf); }while( got<0 && errno==EINTR );
+      robust_close(0, fd, __LINE__);
+    }
+  }
+#endif
+  return nBuf;
+}
+
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+** The argument is the number of microseconds we want to sleep.
+** The return value is the number of microseconds of sleep actually
+** requested from the underlying operating system, a number which
+** might be greater than or equal to the argument, but not less
+** than the argument.
+*/
+static int unixSleep(sqlite3_vfs *NotUsed, int microseconds){
+#if !defined(HAVE_NANOSLEEP) || HAVE_NANOSLEEP+0
+  struct timespec sp;
+  sp.tv_sec = microseconds / 1000000;
+  sp.tv_nsec = (microseconds % 1000000) * 1000;
+
+  /* Almost all modern unix systems support nanosleep().  But if you are
+  ** compiling for one of the rare exceptions, you can use
+  ** -DHAVE_NANOSLEEP=0 (perhaps in conjuction with -DHAVE_USLEEP if
+  ** usleep() is available) in order to bypass the use of nanosleep() */
+  nanosleep(&sp, NULL);
+
+  UNUSED_PARAMETER(NotUsed);
+  return microseconds;
+#elif defined(HAVE_USLEEP) && HAVE_USLEEP
+  if( microseconds>=1000000 ) sleep(microseconds/1000000);
+  if( microseconds%1000000 ) usleep(microseconds%1000000);
+  UNUSED_PARAMETER(NotUsed);
+  return microseconds;
+#else
+  int seconds = (microseconds+999999)/1000000;
+  sleep(seconds);
+  UNUSED_PARAMETER(NotUsed);
+  return seconds*1000000;
+#endif
+}
+
+/*
+** The following variable, if set to a non-zero value, is interpreted as
+** the number of seconds since 1970 and is used to set the result of
+** sqlite3OsCurrentTime() during testing.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_current_time = 0;  /* Fake system time in seconds since 1970. */
+#endif
+
+/*
+** Find the current time (in Universal Coordinated Time).  Write into *piNow
+** the current time and date as a Julian Day number times 86_400_000.  In
+** other words, write into *piNow the number of milliseconds since the Julian
+** epoch of noon in Greenwich on November 24, 4714 B.C according to the
+** proleptic Gregorian calendar.
+**
+** On success, return SQLITE_OK.  Return SQLITE_ERROR if the time and date
+** cannot be found.
+*/
+static int unixCurrentTimeInt64(sqlite3_vfs *NotUsed, sqlite3_int64 *piNow){
+  static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+  int rc = SQLITE_OK;
+#if defined(NO_GETTOD)
+  time_t t;
+  time(&t);
+  *piNow = ((sqlite3_int64)t)*1000 + unixEpoch;
+#elif OS_VXWORKS
+  struct timespec sNow;
+  clock_gettime(CLOCK_REALTIME, &sNow);
+  *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_nsec/1000000;
+#else
+  struct timeval sNow;
+  (void)gettimeofday(&sNow, 0);  /* Cannot fail given valid arguments */
+  *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_usec/1000;
+#endif
+
+#ifdef SQLITE_TEST
+  if( sqlite3_current_time ){
+    *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch;
+  }
+#endif
+  UNUSED_PARAMETER(NotUsed);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Find the current time (in Universal Coordinated Time).  Write the
+** current time and date as a Julian Day number into *prNow and
+** return 0.  Return 1 if the time and date cannot be found.
+*/
+static int unixCurrentTime(sqlite3_vfs *NotUsed, double *prNow){
+  sqlite3_int64 i = 0;
+  int rc;
+  UNUSED_PARAMETER(NotUsed);
+  rc = unixCurrentTimeInt64(0, &i);
+  *prNow = i/86400000.0;
+  return rc;
+}
+#else
+# define unixCurrentTime 0
+#endif
+
+/*
+** The xGetLastError() method is designed to return a better
+** low-level error message when operating-system problems come up
+** during SQLite operation.  Only the integer return code is currently
+** used.
+*/
+static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
+  UNUSED_PARAMETER(NotUsed);
+  UNUSED_PARAMETER(NotUsed2);
+  UNUSED_PARAMETER(NotUsed3);
+  return errno;
+}
+
+
+/*
+************************ End of sqlite3_vfs methods ***************************
+******************************************************************************/
+
+/******************************************************************************
+************************** Begin Proxy Locking ********************************
+**
+** Proxy locking is a "uber-locking-method" in this sense:  It uses the
+** other locking methods on secondary lock files.  Proxy locking is a
+** meta-layer over top of the primitive locking implemented above.  For
+** this reason, the division that implements of proxy locking is deferred
+** until late in the file (here) after all of the other I/O methods have
+** been defined - so that the primitive locking methods are available
+** as services to help with the implementation of proxy locking.
+**
+****
+**
+** The default locking schemes in SQLite use byte-range locks on the
+** database file to coordinate safe, concurrent access by multiple readers
+** and writers [http://sqlite.org/lockingv3.html].  The five file locking
+** states (UNLOCKED, PENDING, SHARED, RESERVED, EXCLUSIVE) are implemented
+** as POSIX read & write locks over fixed set of locations (via fsctl),
+** on AFP and SMB only exclusive byte-range locks are available via fsctl
+** with _IOWR('z', 23, struct ByteRangeLockPB2) to track the same 5 states.
+** To simulate a F_RDLCK on the shared range, on AFP a randomly selected
+** address in the shared range is taken for a SHARED lock, the entire
+** shared range is taken for an EXCLUSIVE lock):
+**
+**      PENDING_BYTE        0x40000000
+**      RESERVED_BYTE       0x40000001
+**      SHARED_RANGE        0x40000002 -> 0x40000200
+**
+** This works well on the local file system, but shows a nearly 100x
+** slowdown in read performance on AFP because the AFP client disables
+** the read cache when byte-range locks are present.  Enabling the read
+** cache exposes a cache coherency problem that is present on all OS X
+** supported network file systems.  NFS and AFP both observe the
+** close-to-open semantics for ensuring cache coherency
+** [http://nfs.sourceforge.net/#faq_a8], which does not effectively
+** address the requirements for concurrent database access by multiple
+** readers and writers
+** [http://www.nabble.com/SQLite-on-NFS-cache-coherency-td15655701.html].
+**
+** To address the performance and cache coherency issues, proxy file locking
+** changes the way database access is controlled by limiting access to a
+** single host at a time and moving file locks off of the database file
+** and onto a proxy file on the local file system.
+**
+**
+** Using proxy locks
+** -----------------
+**
+** C APIs
+**
+**  sqlite3_file_control(db, dbname, SQLITE_FCNTL_SET_LOCKPROXYFILE,
+**                       <proxy_path> | ":auto:");
+**  sqlite3_file_control(db, dbname, SQLITE_FCNTL_GET_LOCKPROXYFILE,
+**                       &<proxy_path>);
+**
+**
+** SQL pragmas
+**
+**  PRAGMA [database.]lock_proxy_file=<proxy_path> | :auto:
+**  PRAGMA [database.]lock_proxy_file
+**
+** Specifying ":auto:" means that if there is a conch file with a matching
+** host ID in it, the proxy path in the conch file will be used, otherwise
+** a proxy path based on the user's temp dir
+** (via confstr(_CS_DARWIN_USER_TEMP_DIR,...)) will be used and the
+** actual proxy file name is generated from the name and path of the
+** database file.  For example:
+**
+**       For database path "/Users/me/foo.db"
+**       The lock path will be "<tmpdir>/sqliteplocks/_Users_me_foo.db:auto:")
+**
+** Once a lock proxy is configured for a database connection, it can not
+** be removed, however it may be switched to a different proxy path via
+** the above APIs (assuming the conch file is not being held by another
+** connection or process).
+**
+**
+** How proxy locking works
+** -----------------------
+**
+** Proxy file locking relies primarily on two new supporting files:
+**
+**   *  conch file to limit access to the database file to a single host
+**      at a time
+**
+**   *  proxy file to act as a proxy for the advisory locks normally
+**      taken on the database
+**
+** The conch file - to use a proxy file, sqlite must first "hold the conch"
+** by taking an sqlite-style shared lock on the conch file, reading the
+** contents and comparing the host's unique host ID (see below) and lock
+** proxy path against the values stored in the conch.  The conch file is
+** stored in the same directory as the database file and the file name
+** is patterned after the database file name as ".<databasename>-conch".
+** If the conch file does not exist, or its contents do not match the
+** host ID and/or proxy path, then the lock is escalated to an exclusive
+** lock and the conch file contents is updated with the host ID and proxy
+** path and the lock is downgraded to a shared lock again.  If the conch
+** is held by another process (with a shared lock), the exclusive lock
+** will fail and SQLITE_BUSY is returned.
+**
+** The proxy file - a single-byte file used for all advisory file locks
+** normally taken on the database file.   This allows for safe sharing
+** of the database file for multiple readers and writers on the same
+** host (the conch ensures that they all use the same local lock file).
+**
+** Requesting the lock proxy does not immediately take the conch, it is
+** only taken when the first request to lock database file is made.
+** This matches the semantics of the traditional locking behavior, where
+** opening a connection to a database file does not take a lock on it.
+** The shared lock and an open file descriptor are maintained until
+** the connection to the database is closed.
+**
+** The proxy file and the lock file are never deleted so they only need
+** to be created the first time they are used.
+**
+** Configuration options
+** ---------------------
+**
+**  SQLITE_PREFER_PROXY_LOCKING
+**
+**       Database files accessed on non-local file systems are
+**       automatically configured for proxy locking, lock files are
+**       named automatically using the same logic as
+**       PRAGMA lock_proxy_file=":auto:"
+**
+**  SQLITE_PROXY_DEBUG
+**
+**       Enables the logging of error messages during host id file
+**       retrieval and creation
+**
+**  LOCKPROXYDIR
+**
+**       Overrides the default directory used for lock proxy files that
+**       are named automatically via the ":auto:" setting
+**
+**  SQLITE_DEFAULT_PROXYDIR_PERMISSIONS
+**
+**       Permissions to use when creating a directory for storing the
+**       lock proxy files, only used when LOCKPROXYDIR is not set.
+**
+**
+** As mentioned above, when compiled with SQLITE_PREFER_PROXY_LOCKING,
+** setting the environment variable SQLITE_FORCE_PROXY_LOCKING to 1 will
+** force proxy locking to be used for every database file opened, and 0
+** will force automatic proxy locking to be disabled for all database
+** files (explicitly calling the SQLITE_FCNTL_SET_LOCKPROXYFILE pragma or
+** sqlite_file_control API is not affected by SQLITE_FORCE_PROXY_LOCKING).
+*/
+
+/*
+** Proxy locking is only available on MacOSX
+*/
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+
+/*
+** The proxyLockingContext has the path and file structures for the remote
+** and local proxy files in it
+*/
+typedef struct proxyLockingContext proxyLockingContext;
+struct proxyLockingContext {
+  unixFile *conchFile;         /* Open conch file */
+  char *conchFilePath;         /* Name of the conch file */
+  unixFile *lockProxy;         /* Open proxy lock file */
+  char *lockProxyPath;         /* Name of the proxy lock file */
+  char *dbPath;                /* Name of the open file */
+  int conchHeld;               /* 1 if the conch is held, -1 if lockless */
+  int nFails;                  /* Number of conch taking failures */
+  void *oldLockingContext;     /* Original lockingcontext to restore on close */
+  sqlite3_io_methods const *pOldMethod;     /* Original I/O methods for close */
+};
+
+/*
+** The proxy lock file path for the database at dbPath is written into lPath,
+** which must point to valid, writable memory large enough for a maxLen length
+** file path.
+*/
+static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
+  int len;
+  int dbLen;
+  int i;
+
+#ifdef LOCKPROXYDIR
+  len = strlcpy(lPath, LOCKPROXYDIR, maxLen);
+#else
+# ifdef _CS_DARWIN_USER_TEMP_DIR
+  {
+    if( !confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen) ){
+      OSTRACE(("GETLOCKPATH  failed %s errno=%d pid=%d\n",
+               lPath, errno, osGetpid(0)));
+      return SQLITE_IOERR_LOCK;
+    }
+    len = strlcat(lPath, "sqliteplocks", maxLen);
+  }
+# else
+  len = strlcpy(lPath, "/tmp/", maxLen);
+# endif
+#endif
+
+  if( lPath[len-1]!='/' ){
+    len = strlcat(lPath, "/", maxLen);
+  }
+
+  /* transform the db path to a unique cache name */
+  dbLen = (int)strlen(dbPath);
+  for( i=0; i<dbLen && (i+len+7)<(int)maxLen; i++){
+    char c = dbPath[i];
+    lPath[i+len] = (c=='/')?'_':c;
+  }
+  lPath[i+len]='\0';
+  strlcat(lPath, ":auto:", maxLen);
+  OSTRACE(("GETLOCKPATH  proxy lock path=%s pid=%d\n", lPath, osGetpid(0)));
+  return SQLITE_OK;
+}
+
+/*
+ ** Creates the lock file and any missing directories in lockPath
+ */
+static int proxyCreateLockPath(const char *lockPath){
+  int i, len;
+  char buf[MAXPATHLEN];
+  int start = 0;
+
+  assert(lockPath!=NULL);
+  /* try to create all the intermediate directories */
+  len = (int)strlen(lockPath);
+  buf[0] = lockPath[0];
+  for( i=1; i<len; i++ ){
+    if( lockPath[i] == '/' && (i - start > 0) ){
+      /* only mkdir if leaf dir != "." or "/" or ".." */
+      if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/')
+         || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){
+        buf[i]='\0';
+        if( osMkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
+          int err=errno;
+          if( err!=EEXIST ) {
+            OSTRACE(("CREATELOCKPATH  FAILED creating %s, "
+                     "'%s' proxy lock path=%s pid=%d\n",
+                     buf, strerror(err), lockPath, osGetpid(0)));
+            return err;
+          }
+        }
+      }
+      start=i+1;
+    }
+    buf[i] = lockPath[i];
+  }
+  OSTRACE(("CREATELOCKPATH  proxy lock path=%s pid=%d\n",lockPath,osGetpid(0)));
+  return 0;
+}
+
+/*
+** Create a new VFS file descriptor (stored in memory obtained from
+** sqlite3_malloc) and open the file named "path" in the file descriptor.
+**
+** The caller is responsible not only for closing the file descriptor
+** but also for freeing the memory associated with the file descriptor.
+*/
+static int proxyCreateUnixFile(
+    const char *path,        /* path for the new unixFile */
+    unixFile **ppFile,       /* unixFile created and returned by ref */
+    int islockfile           /* if non zero missing dirs will be created */
+) {
+  int fd = -1;
+  unixFile *pNew;
+  int rc = SQLITE_OK;
+  int openFlags = O_RDWR | O_CREAT | O_NOFOLLOW;
+  sqlite3_vfs dummyVfs;
+  int terrno = 0;
+  UnixUnusedFd *pUnused = NULL;
+
+  /* 1. first try to open/create the file
+  ** 2. if that fails, and this is a lock file (not-conch), try creating
+  ** the parent directories and then try again.
+  ** 3. if that fails, try to open the file read-only
+  ** otherwise return BUSY (if lock file) or CANTOPEN for the conch file
+  */
+  pUnused = findReusableFd(path, openFlags);
+  if( pUnused ){
+    fd = pUnused->fd;
+  }else{
+    pUnused = sqlite3_malloc64(sizeof(*pUnused));
+    if( !pUnused ){
+      return SQLITE_NOMEM_BKPT;
+    }
+  }
+  if( fd<0 ){
+    fd = robust_open(path, openFlags, 0);
+    terrno = errno;
+    if( fd<0 && errno==ENOENT && islockfile ){
+      if( proxyCreateLockPath(path) == SQLITE_OK ){
+        fd = robust_open(path, openFlags, 0);
+      }
+    }
+  }
+  if( fd<0 ){
+    openFlags = O_RDONLY | O_NOFOLLOW;
+    fd = robust_open(path, openFlags, 0);
+    terrno = errno;
+  }
+  if( fd<0 ){
+    if( islockfile ){
+      return SQLITE_BUSY;
+    }
+    switch (terrno) {
+      case EACCES:
+        return SQLITE_PERM;
+      case EIO:
+        return SQLITE_IOERR_LOCK; /* even though it is the conch */
+      default:
+        return SQLITE_CANTOPEN_BKPT;
+    }
+  }
+
+  pNew = (unixFile *)sqlite3_malloc64(sizeof(*pNew));
+  if( pNew==NULL ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto end_create_proxy;
+  }
+  memset(pNew, 0, sizeof(unixFile));
+  pNew->openFlags = openFlags;
+  memset(&dummyVfs, 0, sizeof(dummyVfs));
+  dummyVfs.pAppData = (void*)&autolockIoFinder;
+  dummyVfs.zName = "dummy";
+  pUnused->fd = fd;
+  pUnused->flags = openFlags;
+  pNew->pPreallocatedUnused = pUnused;
+
+  rc = fillInUnixFile(&dummyVfs, fd, (sqlite3_file*)pNew, path, 0);
+  if( rc==SQLITE_OK ){
+    *ppFile = pNew;
+    return SQLITE_OK;
+  }
+end_create_proxy:
+  robust_close(pNew, fd, __LINE__);
+  sqlite3_free(pNew);
+  sqlite3_free(pUnused);
+  return rc;
+}
+
+#ifdef SQLITE_TEST
+/* simulate multiple hosts by creating unique hostid file paths */
+SQLITE_API int sqlite3_hostid_num = 0;
+#endif
+
+#define PROXY_HOSTIDLEN    16  /* conch file host id length */
+
+#if HAVE_GETHOSTUUID
+/* Not always defined in the headers as it ought to be */
+extern int gethostuuid(uuid_t id, const struct timespec *wait);
+#endif
+
+/* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN
+** bytes of writable memory.
+*/
+static int proxyGetHostID(unsigned char *pHostID, int *pError){
+  assert(PROXY_HOSTIDLEN == sizeof(uuid_t));
+  memset(pHostID, 0, PROXY_HOSTIDLEN);
+#if HAVE_GETHOSTUUID
+  {
+    struct timespec timeout = {1, 0}; /* 1 sec timeout */
+    if( gethostuuid(pHostID, &timeout) ){
+      int err = errno;
+      if( pError ){
+        *pError = err;
+      }
+      return SQLITE_IOERR;
+    }
+  }
+#else
+  UNUSED_PARAMETER(pError);
+#endif
+#ifdef SQLITE_TEST
+  /* simulate multiple hosts by creating unique hostid file paths */
+  if( sqlite3_hostid_num != 0){
+    pHostID[0] = (char)(pHostID[0] + (char)(sqlite3_hostid_num & 0xFF));
+  }
+#endif
+
+  return SQLITE_OK;
+}
+
+/* The conch file contains the header, host id and lock file path
+ */
+#define PROXY_CONCHVERSION 2   /* 1-byte header, 16-byte host id, path */
+#define PROXY_HEADERLEN    1   /* conch file header length */
+#define PROXY_PATHINDEX    (PROXY_HEADERLEN+PROXY_HOSTIDLEN)
+#define PROXY_MAXCONCHLEN  (PROXY_HEADERLEN+PROXY_HOSTIDLEN+MAXPATHLEN)
+
+/*
+** Takes an open conch file, copies the contents to a new path and then moves
+** it back.  The newly created file's file descriptor is assigned to the
+** conch file structure and finally the original conch file descriptor is
+** closed.  Returns zero if successful.
+*/
+static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){
+  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+  unixFile *conchFile = pCtx->conchFile;
+  char tPath[MAXPATHLEN];
+  char buf[PROXY_MAXCONCHLEN];
+  char *cPath = pCtx->conchFilePath;
+  size_t readLen = 0;
+  size_t pathLen = 0;
+  char errmsg[64] = "";
+  int fd = -1;
+  int rc = -1;
+  UNUSED_PARAMETER(myHostID);
+
+  /* create a new path by replace the trailing '-conch' with '-break' */
+  pathLen = strlcpy(tPath, cPath, MAXPATHLEN);
+  if( pathLen>MAXPATHLEN || pathLen<6 ||
+     (strlcpy(&tPath[pathLen-5], "break", 6) != 5) ){
+    sqlite3_snprintf(sizeof(errmsg),errmsg,"path error (len %d)",(int)pathLen);
+    goto end_breaklock;
+  }
+  /* read the conch content */
+  readLen = osPread(conchFile->h, buf, PROXY_MAXCONCHLEN, 0);
+  if( readLen<PROXY_PATHINDEX ){
+    sqlite3_snprintf(sizeof(errmsg),errmsg,"read error (len %d)",(int)readLen);
+    goto end_breaklock;
+  }
+  /* write it out to the temporary break file */
+  fd = robust_open(tPath, (O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW), 0);
+  if( fd<0 ){
+    sqlite3_snprintf(sizeof(errmsg), errmsg, "create failed (%d)", errno);
+    goto end_breaklock;
+  }
+  if( osPwrite(fd, buf, readLen, 0) != (ssize_t)readLen ){
+    sqlite3_snprintf(sizeof(errmsg), errmsg, "write failed (%d)", errno);
+    goto end_breaklock;
+  }
+  if( rename(tPath, cPath) ){
+    sqlite3_snprintf(sizeof(errmsg), errmsg, "rename failed (%d)", errno);
+    goto end_breaklock;
+  }
+  rc = 0;
+  fprintf(stderr, "broke stale lock on %s\n", cPath);
+  robust_close(pFile, conchFile->h, __LINE__);
+  conchFile->h = fd;
+  conchFile->openFlags = O_RDWR | O_CREAT;
+
+end_breaklock:
+  if( rc ){
+    if( fd>=0 ){
+      osUnlink(tPath);
+      robust_close(pFile, fd, __LINE__);
+    }
+    fprintf(stderr, "failed to break stale lock on %s, %s\n", cPath, errmsg);
+  }
+  return rc;
+}
+
+/* Take the requested lock on the conch file and break a stale lock if the
+** host id matches.
+*/
+static int proxyConchLock(unixFile *pFile, uuid_t myHostID, int lockType){
+  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+  unixFile *conchFile = pCtx->conchFile;
+  int rc = SQLITE_OK;
+  int nTries = 0;
+  struct timespec conchModTime;
+
+  memset(&conchModTime, 0, sizeof(conchModTime));
+  do {
+    rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
+    nTries ++;
+    if( rc==SQLITE_BUSY ){
+      /* If the lock failed (busy):
+       * 1st try: get the mod time of the conch, wait 0.5s and try again.
+       * 2nd try: fail if the mod time changed or host id is different, wait
+       *           10 sec and try again
+       * 3rd try: break the lock unless the mod time has changed.
+       */
+      struct stat buf;
+      if( osFstat(conchFile->h, &buf) ){
+        storeLastErrno(pFile, errno);
+        return SQLITE_IOERR_LOCK;
+      }
+
+      if( nTries==1 ){
+        conchModTime = buf.st_mtimespec;
+        unixSleep(0,500000); /* wait 0.5 sec and try the lock again*/
+        continue;
+      }
+
+      assert( nTries>1 );
+      if( conchModTime.tv_sec != buf.st_mtimespec.tv_sec ||
+         conchModTime.tv_nsec != buf.st_mtimespec.tv_nsec ){
+        return SQLITE_BUSY;
+      }
+
+      if( nTries==2 ){
+        char tBuf[PROXY_MAXCONCHLEN];
+        int len = osPread(conchFile->h, tBuf, PROXY_MAXCONCHLEN, 0);
+        if( len<0 ){
+          storeLastErrno(pFile, errno);
+          return SQLITE_IOERR_LOCK;
+        }
+        if( len>PROXY_PATHINDEX && tBuf[0]==(char)PROXY_CONCHVERSION){
+          /* don't break the lock if the host id doesn't match */
+          if( 0!=memcmp(&tBuf[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN) ){
+            return SQLITE_BUSY;
+          }
+        }else{
+          /* don't break the lock on short read or a version mismatch */
+          return SQLITE_BUSY;
+        }
+        unixSleep(0,10000000); /* wait 10 sec and try the lock again */
+        continue;
+      }
+
+      assert( nTries==3 );
+      if( 0==proxyBreakConchLock(pFile, myHostID) ){
+        rc = SQLITE_OK;
+        if( lockType==EXCLUSIVE_LOCK ){
+          rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, SHARED_LOCK);
+        }
+        if( !rc ){
+          rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
+        }
+      }
+    }
+  } while( rc==SQLITE_BUSY && nTries<3 );
+
+  return rc;
+}
+
+/* Takes the conch by taking a shared lock and read the contents conch, if
+** lockPath is non-NULL, the host ID and lock file path must match.  A NULL
+** lockPath means that the lockPath in the conch file will be used if the
+** host IDs match, or a new lock path will be generated automatically
+** and written to the conch file.
+*/
+static int proxyTakeConch(unixFile *pFile){
+  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+
+  if( pCtx->conchHeld!=0 ){
+    return SQLITE_OK;
+  }else{
+    unixFile *conchFile = pCtx->conchFile;
+    uuid_t myHostID;
+    int pError = 0;
+    char readBuf[PROXY_MAXCONCHLEN];
+    char lockPath[MAXPATHLEN];
+    char *tempLockPath = NULL;
+    int rc = SQLITE_OK;
+    int createConch = 0;
+    int hostIdMatch = 0;
+    int readLen = 0;
+    int tryOldLockPath = 0;
+    int forceNewLockPath = 0;
+
+    OSTRACE(("TAKECONCH  %d for %s pid=%d\n", conchFile->h,
+             (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"),
+             osGetpid(0)));
+
+    rc = proxyGetHostID(myHostID, &pError);
+    if( (rc&0xff)==SQLITE_IOERR ){
+      storeLastErrno(pFile, pError);
+      goto end_takeconch;
+    }
+    rc = proxyConchLock(pFile, myHostID, SHARED_LOCK);
+    if( rc!=SQLITE_OK ){
+      goto end_takeconch;
+    }
+    /* read the existing conch file */
+    readLen = seekAndRead((unixFile*)conchFile, 0, readBuf, PROXY_MAXCONCHLEN);
+    if( readLen<0 ){
+      /* I/O error: lastErrno set by seekAndRead */
+      storeLastErrno(pFile, conchFile->lastErrno);
+      rc = SQLITE_IOERR_READ;
+      goto end_takeconch;
+    }else if( readLen<=(PROXY_HEADERLEN+PROXY_HOSTIDLEN) ||
+             readBuf[0]!=(char)PROXY_CONCHVERSION ){
+      /* a short read or version format mismatch means we need to create a new
+      ** conch file.
+      */
+      createConch = 1;
+    }
+    /* if the host id matches and the lock path already exists in the conch
+    ** we'll try to use the path there, if we can't open that path, we'll
+    ** retry with a new auto-generated path
+    */
+    do { /* in case we need to try again for an :auto: named lock file */
+
+      if( !createConch && !forceNewLockPath ){
+        hostIdMatch = !memcmp(&readBuf[PROXY_HEADERLEN], myHostID,
+                                  PROXY_HOSTIDLEN);
+        /* if the conch has data compare the contents */
+        if( !pCtx->lockProxyPath ){
+          /* for auto-named local lock file, just check the host ID and we'll
+           ** use the local lock file path that's already in there
+           */
+          if( hostIdMatch ){
+            size_t pathLen = (readLen - PROXY_PATHINDEX);
+
+            if( pathLen>=MAXPATHLEN ){
+              pathLen=MAXPATHLEN-1;
+            }
+            memcpy(lockPath, &readBuf[PROXY_PATHINDEX], pathLen);
+            lockPath[pathLen] = 0;
+            tempLockPath = lockPath;
+            tryOldLockPath = 1;
+            /* create a copy of the lock path if the conch is taken */
+            goto end_takeconch;
+          }
+        }else if( hostIdMatch
+               && !strncmp(pCtx->lockProxyPath, &readBuf[PROXY_PATHINDEX],
+                           readLen-PROXY_PATHINDEX)
+        ){
+          /* conch host and lock path match */
+          goto end_takeconch;
+        }
+      }
+
+      /* if the conch isn't writable and doesn't match, we can't take it */
+      if( (conchFile->openFlags&O_RDWR) == 0 ){
+        rc = SQLITE_BUSY;
+        goto end_takeconch;
+      }
+
+      /* either the conch didn't match or we need to create a new one */
+      if( !pCtx->lockProxyPath ){
+        proxyGetLockPath(pCtx->dbPath, lockPath, MAXPATHLEN);
+        tempLockPath = lockPath;
+        /* create a copy of the lock path _only_ if the conch is taken */
+      }
+
+      /* update conch with host and path (this will fail if other process
+      ** has a shared lock already), if the host id matches, use the big
+      ** stick.
+      */
+      futimes(conchFile->h, NULL);
+      if( hostIdMatch && !createConch ){
+        if( conchFile->pInode && conchFile->pInode->nShared>1 ){
+          /* We are trying for an exclusive lock but another thread in this
+           ** same process is still holding a shared lock. */
+          rc = SQLITE_BUSY;
+        } else {
+          rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK);
+        }
+      }else{
+        rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK);
+      }
+      if( rc==SQLITE_OK ){
+        char writeBuffer[PROXY_MAXCONCHLEN];
+        int writeSize = 0;
+
+        writeBuffer[0] = (char)PROXY_CONCHVERSION;
+        memcpy(&writeBuffer[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN);
+        if( pCtx->lockProxyPath!=NULL ){
+          strlcpy(&writeBuffer[PROXY_PATHINDEX], pCtx->lockProxyPath,
+                  MAXPATHLEN);
+        }else{
+          strlcpy(&writeBuffer[PROXY_PATHINDEX], tempLockPath, MAXPATHLEN);
+        }
+        writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]);
+        robust_ftruncate(conchFile->h, writeSize);
+        rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0);
+        full_fsync(conchFile->h,0,0);
+        /* If we created a new conch file (not just updated the contents of a
+         ** valid conch file), try to match the permissions of the database
+         */
+        if( rc==SQLITE_OK && createConch ){
+          struct stat buf;
+          int err = osFstat(pFile->h, &buf);
+          if( err==0 ){
+            mode_t cmode = buf.st_mode&(S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP |
+                                        S_IROTH|S_IWOTH);
+            /* try to match the database file R/W permissions, ignore failure */
+#ifndef SQLITE_PROXY_DEBUG
+            osFchmod(conchFile->h, cmode);
+#else
+            do{
+              rc = osFchmod(conchFile->h, cmode);
+            }while( rc==(-1) && errno==EINTR );
+            if( rc!=0 ){
+              int code = errno;
+              fprintf(stderr, "fchmod %o FAILED with %d %s\n",
+                      cmode, code, strerror(code));
+            } else {
+              fprintf(stderr, "fchmod %o SUCCEDED\n",cmode);
+            }
+          }else{
+            int code = errno;
+            fprintf(stderr, "STAT FAILED[%d] with %d %s\n",
+                    err, code, strerror(code));
+#endif
+          }
+        }
+      }
+      conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK);
+
+    end_takeconch:
+      OSTRACE(("TRANSPROXY: CLOSE  %d\n", pFile->h));
+      if( rc==SQLITE_OK && pFile->openFlags ){
+        int fd;
+        if( pFile->h>=0 ){
+          robust_close(pFile, pFile->h, __LINE__);
+        }
+        pFile->h = -1;
+        fd = robust_open(pCtx->dbPath, pFile->openFlags, 0);
+        OSTRACE(("TRANSPROXY: OPEN  %d\n", fd));
+        if( fd>=0 ){
+          pFile->h = fd;
+        }else{
+          rc=SQLITE_CANTOPEN_BKPT; /* SQLITE_BUSY? proxyTakeConch called
+           during locking */
+        }
+      }
+      if( rc==SQLITE_OK && !pCtx->lockProxy ){
+        char *path = tempLockPath ? tempLockPath : pCtx->lockProxyPath;
+        rc = proxyCreateUnixFile(path, &pCtx->lockProxy, 1);
+        if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && tryOldLockPath ){
+          /* we couldn't create the proxy lock file with the old lock file path
+           ** so try again via auto-naming
+           */
+          forceNewLockPath = 1;
+          tryOldLockPath = 0;
+          continue; /* go back to the do {} while start point, try again */
+        }
+      }
+      if( rc==SQLITE_OK ){
+        /* Need to make a copy of path if we extracted the value
+         ** from the conch file or the path was allocated on the stack
+         */
+        if( tempLockPath ){
+          pCtx->lockProxyPath = sqlite3DbStrDup(0, tempLockPath);
+          if( !pCtx->lockProxyPath ){
+            rc = SQLITE_NOMEM_BKPT;
+          }
+        }
+      }
+      if( rc==SQLITE_OK ){
+        pCtx->conchHeld = 1;
+
+        if( pCtx->lockProxy->pMethod == &afpIoMethods ){
+          afpLockingContext *afpCtx;
+          afpCtx = (afpLockingContext *)pCtx->lockProxy->lockingContext;
+          afpCtx->dbPath = pCtx->lockProxyPath;
+        }
+      } else {
+        conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
+      }
+      OSTRACE(("TAKECONCH  %d %s\n", conchFile->h,
+               rc==SQLITE_OK?"ok":"failed"));
+      return rc;
+    } while (1); /* in case we need to retry the :auto: lock file -
+                 ** we should never get here except via the 'continue' call. */
+  }
+}
+
+/*
+** If pFile holds a lock on a conch file, then release that lock.
+*/
+static int proxyReleaseConch(unixFile *pFile){
+  int rc = SQLITE_OK;         /* Subroutine return code */
+  proxyLockingContext *pCtx;  /* The locking context for the proxy lock */
+  unixFile *conchFile;        /* Name of the conch file */
+
+  pCtx = (proxyLockingContext *)pFile->lockingContext;
+  conchFile = pCtx->conchFile;
+  OSTRACE(("RELEASECONCH  %d for %s pid=%d\n", conchFile->h,
+           (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"),
+           osGetpid(0)));
+  if( pCtx->conchHeld>0 ){
+    rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
+  }
+  pCtx->conchHeld = 0;
+  OSTRACE(("RELEASECONCH  %d %s\n", conchFile->h,
+           (rc==SQLITE_OK ? "ok" : "failed")));
+  return rc;
+}
+
+/*
+** Given the name of a database file, compute the name of its conch file.
+** Store the conch filename in memory obtained from sqlite3_malloc64().
+** Make *pConchPath point to the new name.  Return SQLITE_OK on success
+** or SQLITE_NOMEM if unable to obtain memory.
+**
+** The caller is responsible for ensuring that the allocated memory
+** space is eventually freed.
+**
+** *pConchPath is set to NULL if a memory allocation error occurs.
+*/
+static int proxyCreateConchPathname(char *dbPath, char **pConchPath){
+  int i;                        /* Loop counter */
+  int len = (int)strlen(dbPath); /* Length of database filename - dbPath */
+  char *conchPath;              /* buffer in which to construct conch name */
+
+  /* Allocate space for the conch filename and initialize the name to
+  ** the name of the original database file. */
+  *pConchPath = conchPath = (char *)sqlite3_malloc64(len + 8);
+  if( conchPath==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  memcpy(conchPath, dbPath, len+1);
+
+  /* now insert a "." before the last / character */
+  for( i=(len-1); i>=0; i-- ){
+    if( conchPath[i]=='/' ){
+      i++;
+      break;
+    }
+  }
+  conchPath[i]='.';
+  while ( i<len ){
+    conchPath[i+1]=dbPath[i];
+    i++;
+  }
+
+  /* append the "-conch" suffix to the file */
+  memcpy(&conchPath[i+1], "-conch", 7);
+  assert( (int)strlen(conchPath) == len+7 );
+
+  return SQLITE_OK;
+}
+
+
+/* Takes a fully configured proxy locking-style unix file and switches
+** the local lock file path
+*/
+static int switchLockProxyPath(unixFile *pFile, const char *path) {
+  proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext;
+  char *oldPath = pCtx->lockProxyPath;
+  int rc = SQLITE_OK;
+
+  if( pFile->eFileLock!=NO_LOCK ){
+    return SQLITE_BUSY;
+  }
+
+  /* nothing to do if the path is NULL, :auto: or matches the existing path */
+  if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ||
+    (oldPath && !strncmp(oldPath, path, MAXPATHLEN)) ){
+    return SQLITE_OK;
+  }else{
+    unixFile *lockProxy = pCtx->lockProxy;
+    pCtx->lockProxy=NULL;
+    pCtx->conchHeld = 0;
+    if( lockProxy!=NULL ){
+      rc=lockProxy->pMethod->xClose((sqlite3_file *)lockProxy);
+      if( rc ) return rc;
+      sqlite3_free(lockProxy);
+    }
+    sqlite3_free(oldPath);
+    pCtx->lockProxyPath = sqlite3DbStrDup(0, path);
+  }
+
+  return rc;
+}
+
+/*
+** pFile is a file that has been opened by a prior xOpen call.  dbPath
+** is a string buffer at least MAXPATHLEN+1 characters in size.
+**
+** This routine find the filename associated with pFile and writes it
+** int dbPath.
+*/
+static int proxyGetDbPathForUnixFile(unixFile *pFile, char *dbPath){
+#if defined(__APPLE__)
+  if( pFile->pMethod == &afpIoMethods ){
+    /* afp style keeps a reference to the db path in the filePath field
+    ** of the struct */
+    assert( (int)strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
+    strlcpy(dbPath, ((afpLockingContext *)pFile->lockingContext)->dbPath,
+            MAXPATHLEN);
+  } else
+#endif
+  if( pFile->pMethod == &dotlockIoMethods ){
+    /* dot lock style uses the locking context to store the dot lock
+    ** file path */
+    int len = strlen((char *)pFile->lockingContext) - strlen(DOTLOCK_SUFFIX);
+    memcpy(dbPath, (char *)pFile->lockingContext, len + 1);
+  }else{
+    /* all other styles use the locking context to store the db file path */
+    assert( strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
+    strlcpy(dbPath, (char *)pFile->lockingContext, MAXPATHLEN);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Takes an already filled in unix file and alters it so all file locking
+** will be performed on the local proxy lock file.  The following fields
+** are preserved in the locking context so that they can be restored and
+** the unix structure properly cleaned up at close time:
+**  ->lockingContext
+**  ->pMethod
+*/
+static int proxyTransformUnixFile(unixFile *pFile, const char *path) {
+  proxyLockingContext *pCtx;
+  char dbPath[MAXPATHLEN+1];       /* Name of the database file */
+  char *lockPath=NULL;
+  int rc = SQLITE_OK;
+
+  if( pFile->eFileLock!=NO_LOCK ){
+    return SQLITE_BUSY;
+  }
+  proxyGetDbPathForUnixFile(pFile, dbPath);
+  if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ){
+    lockPath=NULL;
+  }else{
+    lockPath=(char *)path;
+  }
+
+  OSTRACE(("TRANSPROXY  %d for %s pid=%d\n", pFile->h,
+           (lockPath ? lockPath : ":auto:"), osGetpid(0)));
+
+  pCtx = sqlite3_malloc64( sizeof(*pCtx) );
+  if( pCtx==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  memset(pCtx, 0, sizeof(*pCtx));
+
+  rc = proxyCreateConchPathname(dbPath, &pCtx->conchFilePath);
+  if( rc==SQLITE_OK ){
+    rc = proxyCreateUnixFile(pCtx->conchFilePath, &pCtx->conchFile, 0);
+    if( rc==SQLITE_CANTOPEN && ((pFile->openFlags&O_RDWR) == 0) ){
+      /* if (a) the open flags are not O_RDWR, (b) the conch isn't there, and
+      ** (c) the file system is read-only, then enable no-locking access.
+      ** Ugh, since O_RDONLY==0x0000 we test for !O_RDWR since unixOpen asserts
+      ** that openFlags will have only one of O_RDONLY or O_RDWR.
+      */
+      struct statfs fsInfo;
+      struct stat conchInfo;
+      int goLockless = 0;
+
+      if( osStat(pCtx->conchFilePath, &conchInfo) == -1 ) {
+        int err = errno;
+        if( (err==ENOENT) && (statfs(dbPath, &fsInfo) != -1) ){
+          goLockless = (fsInfo.f_flags&MNT_RDONLY) == MNT_RDONLY;
+        }
+      }
+      if( goLockless ){
+        pCtx->conchHeld = -1; /* read only FS/ lockless */
+        rc = SQLITE_OK;
+      }
+    }
+  }
+  if( rc==SQLITE_OK && lockPath ){
+    pCtx->lockProxyPath = sqlite3DbStrDup(0, lockPath);
+  }
+
+  if( rc==SQLITE_OK ){
+    pCtx->dbPath = sqlite3DbStrDup(0, dbPath);
+    if( pCtx->dbPath==NULL ){
+      rc = SQLITE_NOMEM_BKPT;
+    }
+  }
+  if( rc==SQLITE_OK ){
+    /* all memory is allocated, proxys are created and assigned,
+    ** switch the locking context and pMethod then return.
+    */
+    pCtx->oldLockingContext = pFile->lockingContext;
+    pFile->lockingContext = pCtx;
+    pCtx->pOldMethod = pFile->pMethod;
+    pFile->pMethod = &proxyIoMethods;
+  }else{
+    if( pCtx->conchFile ){
+      pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile);
+      sqlite3_free(pCtx->conchFile);
+    }
+    sqlite3DbFree(0, pCtx->lockProxyPath);
+    sqlite3_free(pCtx->conchFilePath);
+    sqlite3_free(pCtx);
+  }
+  OSTRACE(("TRANSPROXY  %d %s\n", pFile->h,
+           (rc==SQLITE_OK ? "ok" : "failed")));
+  return rc;
+}
+
+
+/*
+** This routine handles sqlite3_file_control() calls that are specific
+** to proxy locking.
+*/
+static int proxyFileControl(sqlite3_file *id, int op, void *pArg){
+  switch( op ){
+    case SQLITE_FCNTL_GET_LOCKPROXYFILE: {
+      unixFile *pFile = (unixFile*)id;
+      if( pFile->pMethod == &proxyIoMethods ){
+        proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext;
+        proxyTakeConch(pFile);
+        if( pCtx->lockProxyPath ){
+          *(const char **)pArg = pCtx->lockProxyPath;
+        }else{
+          *(const char **)pArg = ":auto: (not held)";
+        }
+      } else {
+        *(const char **)pArg = NULL;
+      }
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_SET_LOCKPROXYFILE: {
+      unixFile *pFile = (unixFile*)id;
+      int rc = SQLITE_OK;
+      int isProxyStyle = (pFile->pMethod == &proxyIoMethods);
+      if( pArg==NULL || (const char *)pArg==0 ){
+        if( isProxyStyle ){
+          /* turn off proxy locking - not supported.  If support is added for
+          ** switching proxy locking mode off then it will need to fail if
+          ** the journal mode is WAL mode.
+          */
+          rc = SQLITE_ERROR /*SQLITE_PROTOCOL? SQLITE_MISUSE?*/;
+        }else{
+          /* turn off proxy locking - already off - NOOP */
+          rc = SQLITE_OK;
+        }
+      }else{
+        const char *proxyPath = (const char *)pArg;
+        if( isProxyStyle ){
+          proxyLockingContext *pCtx =
+            (proxyLockingContext*)pFile->lockingContext;
+          if( !strcmp(pArg, ":auto:")
+           || (pCtx->lockProxyPath &&
+               !strncmp(pCtx->lockProxyPath, proxyPath, MAXPATHLEN))
+          ){
+            rc = SQLITE_OK;
+          }else{
+            rc = switchLockProxyPath(pFile, proxyPath);
+          }
+        }else{
+          /* turn on proxy file locking */
+          rc = proxyTransformUnixFile(pFile, proxyPath);
+        }
+      }
+      return rc;
+    }
+    default: {
+      assert( 0 );  /* The call assures that only valid opcodes are sent */
+    }
+  }
+  /*NOTREACHED*/ assert(0);
+  return SQLITE_ERROR;
+}
+
+/*
+** Within this division (the proxying locking implementation) the procedures
+** above this point are all utilities.  The lock-related methods of the
+** proxy-locking sqlite3_io_method object follow.
+*/
+
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int proxyCheckReservedLock(sqlite3_file *id, int *pResOut) {
+  unixFile *pFile = (unixFile*)id;
+  int rc = proxyTakeConch(pFile);
+  if( rc==SQLITE_OK ){
+    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+    if( pCtx->conchHeld>0 ){
+      unixFile *proxy = pCtx->lockProxy;
+      return proxy->pMethod->xCheckReservedLock((sqlite3_file*)proxy, pResOut);
+    }else{ /* conchHeld < 0 is lockless */
+      pResOut=0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int proxyLock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  int rc = proxyTakeConch(pFile);
+  if( rc==SQLITE_OK ){
+    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+    if( pCtx->conchHeld>0 ){
+      unixFile *proxy = pCtx->lockProxy;
+      rc = proxy->pMethod->xLock((sqlite3_file*)proxy, eFileLock);
+      pFile->eFileLock = proxy->eFileLock;
+    }else{
+      /* conchHeld < 0 is lockless */
+    }
+  }
+  return rc;
+}
+
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int proxyUnlock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  int rc = proxyTakeConch(pFile);
+  if( rc==SQLITE_OK ){
+    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+    if( pCtx->conchHeld>0 ){
+      unixFile *proxy = pCtx->lockProxy;
+      rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, eFileLock);
+      pFile->eFileLock = proxy->eFileLock;
+    }else{
+      /* conchHeld < 0 is lockless */
+    }
+  }
+  return rc;
+}
+
+/*
+** Close a file that uses proxy locks.
+*/
+static int proxyClose(sqlite3_file *id) {
+  if( ALWAYS(id) ){
+    unixFile *pFile = (unixFile*)id;
+    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+    unixFile *lockProxy = pCtx->lockProxy;
+    unixFile *conchFile = pCtx->conchFile;
+    int rc = SQLITE_OK;
+
+    if( lockProxy ){
+      rc = lockProxy->pMethod->xUnlock((sqlite3_file*)lockProxy, NO_LOCK);
+      if( rc ) return rc;
+      rc = lockProxy->pMethod->xClose((sqlite3_file*)lockProxy);
+      if( rc ) return rc;
+      sqlite3_free(lockProxy);
+      pCtx->lockProxy = 0;
+    }
+    if( conchFile ){
+      if( pCtx->conchHeld ){
+        rc = proxyReleaseConch(pFile);
+        if( rc ) return rc;
+      }
+      rc = conchFile->pMethod->xClose((sqlite3_file*)conchFile);
+      if( rc ) return rc;
+      sqlite3_free(conchFile);
+    }
+    sqlite3DbFree(0, pCtx->lockProxyPath);
+    sqlite3_free(pCtx->conchFilePath);
+    sqlite3DbFree(0, pCtx->dbPath);
+    /* restore the original locking context and pMethod then close it */
+    pFile->lockingContext = pCtx->oldLockingContext;
+    pFile->pMethod = pCtx->pOldMethod;
+    sqlite3_free(pCtx);
+    return pFile->pMethod->xClose(id);
+  }
+  return SQLITE_OK;
+}
+
+
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+/*
+** The proxy locking style is intended for use with AFP filesystems.
+** And since AFP is only supported on MacOSX, the proxy locking is also
+** restricted to MacOSX.
+**
+**
+******************* End of the proxy lock implementation **********************
+******************************************************************************/
+
+/*
+** Initialize the operating system interface.
+**
+** This routine registers all VFS implementations for unix-like operating
+** systems.  This routine, and the sqlite3_os_end() routine that follows,
+** should be the only routines in this file that are visible from other
+** files.
+**
+** This routine is called once during SQLite initialization and by a
+** single thread.  The memory allocation and mutex subsystems have not
+** necessarily been initialized when this routine is called, and so they
+** should not be used.
+*/
+SQLITE_API int sqlite3_os_init(void){
+  /*
+  ** The following macro defines an initializer for an sqlite3_vfs object.
+  ** The name of the VFS is NAME.  The pAppData is a pointer to a pointer
+  ** to the "finder" function.  (pAppData is a pointer to a pointer because
+  ** silly C90 rules prohibit a void* from being cast to a function pointer
+  ** and so we have to go through the intermediate pointer to avoid problems
+  ** when compiling with -pedantic-errors on GCC.)
+  **
+  ** The FINDER parameter to this macro is the name of the pointer to the
+  ** finder-function.  The finder-function returns a pointer to the
+  ** sqlite_io_methods object that implements the desired locking
+  ** behaviors.  See the division above that contains the IOMETHODS
+  ** macro for addition information on finder-functions.
+  **
+  ** Most finders simply return a pointer to a fixed sqlite3_io_methods
+  ** object.  But the "autolockIoFinder" available on MacOSX does a little
+  ** more than that; it looks at the filesystem type that hosts the
+  ** database file and tries to choose an locking method appropriate for
+  ** that filesystem time.
+  */
+  #define UNIXVFS(VFSNAME, FINDER) {                        \
+    3,                    /* iVersion */                    \
+    sizeof(unixFile),     /* szOsFile */                    \
+    MAX_PATHNAME,         /* mxPathname */                  \
+    0,                    /* pNext */                       \
+    VFSNAME,              /* zName */                       \
+    (void*)&FINDER,       /* pAppData */                    \
+    unixOpen,             /* xOpen */                       \
+    unixDelete,           /* xDelete */                     \
+    unixAccess,           /* xAccess */                     \
+    unixFullPathname,     /* xFullPathname */               \
+    unixDlOpen,           /* xDlOpen */                     \
+    unixDlError,          /* xDlError */                    \
+    unixDlSym,            /* xDlSym */                      \
+    unixDlClose,          /* xDlClose */                    \
+    unixRandomness,       /* xRandomness */                 \
+    unixSleep,            /* xSleep */                      \
+    unixCurrentTime,      /* xCurrentTime */                \
+    unixGetLastError,     /* xGetLastError */               \
+    unixCurrentTimeInt64, /* xCurrentTimeInt64 */           \
+    unixSetSystemCall,    /* xSetSystemCall */              \
+    unixGetSystemCall,    /* xGetSystemCall */              \
+    unixNextSystemCall,   /* xNextSystemCall */             \
+  }
+
+  /*
+  ** All default VFSes for unix are contained in the following array.
+  **
+  ** Note that the sqlite3_vfs.pNext field of the VFS object is modified
+  ** by the SQLite core when the VFS is registered.  So the following
+  ** array cannot be const.
+  */
+  static sqlite3_vfs aVfs[] = {
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+    UNIXVFS("unix",          autolockIoFinder ),
+#elif OS_VXWORKS
+    UNIXVFS("unix",          vxworksIoFinder ),
+#else
+    UNIXVFS("unix",          posixIoFinder ),
+#endif
+    UNIXVFS("unix-none",     nolockIoFinder ),
+    UNIXVFS("unix-dotfile",  dotlockIoFinder ),
+    UNIXVFS("unix-excl",     posixIoFinder ),
+#if OS_VXWORKS
+    UNIXVFS("unix-namedsem", semIoFinder ),
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE || OS_VXWORKS
+    UNIXVFS("unix-posix",    posixIoFinder ),
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE
+    UNIXVFS("unix-flock",    flockIoFinder ),
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+    UNIXVFS("unix-afp",      afpIoFinder ),
+    UNIXVFS("unix-nfs",      nfsIoFinder ),
+    UNIXVFS("unix-proxy",    proxyIoFinder ),
+#endif
+  };
+  unsigned int i;          /* Loop counter */
+
+  /* Double-check that the aSyscall[] array has been constructed
+  ** correctly.  See ticket [bb3a86e890c8e96ab] */
+  assert( ArraySize(aSyscall)==29 );
+
+  /* Register all VFSes defined in the aVfs[] array */
+  for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
+#ifdef SQLITE_DEFAULT_UNIX_VFS
+    sqlite3_vfs_register(&aVfs[i],
+           0==strcmp(aVfs[i].zName,SQLITE_DEFAULT_UNIX_VFS));
+#else
+    sqlite3_vfs_register(&aVfs[i], i==0);
+#endif
+  }
+#ifdef SQLITE_OS_KV_OPTIONAL
+  sqlite3KvvfsInit();
+#endif
+  unixBigLock = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
+
+#ifndef SQLITE_OMIT_WAL
+  /* Validate lock assumptions */
+  assert( SQLITE_SHM_NLOCK==8 );  /* Number of available locks */
+  assert( UNIX_SHM_BASE==120  );  /* Start of locking area */
+  /* Locks:
+  **    WRITE       UNIX_SHM_BASE      120
+  **    CKPT        UNIX_SHM_BASE+1    121
+  **    RECOVER     UNIX_SHM_BASE+2    122
+  **    READ-0      UNIX_SHM_BASE+3    123
+  **    READ-1      UNIX_SHM_BASE+4    124
+  **    READ-2      UNIX_SHM_BASE+5    125
+  **    READ-3      UNIX_SHM_BASE+6    126
+  **    READ-4      UNIX_SHM_BASE+7    127
+  **    DMS         UNIX_SHM_BASE+8    128
+  */
+  assert( UNIX_SHM_DMS==128   );  /* Byte offset of the deadman-switch */
+#endif
+
+  /* Initialize temp file dir array. */
+  unixTempFileInit();
+
+  return SQLITE_OK;
+}
+
+/*
+** Shutdown the operating system interface.
+**
+** Some operating systems might need to do some cleanup in this routine,
+** to release dynamically allocated objects.  But not on unix.
+** This routine is a no-op for unix.
+*/
+SQLITE_API int sqlite3_os_end(void){
+  unixBigLock = 0;
+  return SQLITE_OK;
+}
+
+#endif /* SQLITE_OS_UNIX */
+
+/************** End of os_unix.c *********************************************/
+/************** Begin file os_win.c ******************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to Windows.
+*/
+/* #include "sqliteInt.h" */
+#if SQLITE_OS_WIN               /* This file is used for Windows only */
+
+/*
+** Include code that is common to all os_*.c files
+*/
+/* #include "os_common.h" */
+
+/*
+** Include the header file for the Windows VFS.
+*/
+/* #include "os_win.h" */
+
+/*
+** Compiling and using WAL mode requires several APIs that are only
+** available in Windows platforms based on the NT kernel.
+*/
+#if !SQLITE_OS_WINNT && !defined(SQLITE_OMIT_WAL)
+#  error "WAL mode requires support from the Windows NT kernel, compile\
+ with SQLITE_OMIT_WAL."
+#endif
+
+#if !SQLITE_OS_WINNT && SQLITE_MAX_MMAP_SIZE>0
+#  error "Memory mapped files require support from the Windows NT kernel,\
+ compile with SQLITE_MAX_MMAP_SIZE=0."
+#endif
+
+/*
+** Are most of the Win32 ANSI APIs available (i.e. with certain exceptions
+** based on the sub-platform)?
+*/
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && !defined(SQLITE_WIN32_NO_ANSI)
+#  define SQLITE_WIN32_HAS_ANSI
+#endif
+
+/*
+** Are most of the Win32 Unicode APIs available (i.e. with certain exceptions
+** based on the sub-platform)?
+*/
+#if (SQLITE_OS_WINCE || SQLITE_OS_WINNT || SQLITE_OS_WINRT) && \
+    !defined(SQLITE_WIN32_NO_WIDE)
+#  define SQLITE_WIN32_HAS_WIDE
+#endif
+
+/*
+** Make sure at least one set of Win32 APIs is available.
+*/
+#if !defined(SQLITE_WIN32_HAS_ANSI) && !defined(SQLITE_WIN32_HAS_WIDE)
+#  error "At least one of SQLITE_WIN32_HAS_ANSI and SQLITE_WIN32_HAS_WIDE\
+ must be defined."
+#endif
+
+/*
+** Define the required Windows SDK version constants if they are not
+** already available.
+*/
+#ifndef NTDDI_WIN8
+#  define NTDDI_WIN8                        0x06020000
+#endif
+
+#ifndef NTDDI_WINBLUE
+#  define NTDDI_WINBLUE                     0x06030000
+#endif
+
+#ifndef NTDDI_WINTHRESHOLD
+#  define NTDDI_WINTHRESHOLD                0x06040000
+#endif
+
+/*
+** Check to see if the GetVersionEx[AW] functions are deprecated on the
+** target system.  GetVersionEx was first deprecated in Win8.1.
+*/
+#ifndef SQLITE_WIN32_GETVERSIONEX
+#  if defined(NTDDI_VERSION) && NTDDI_VERSION >= NTDDI_WINBLUE
+#    define SQLITE_WIN32_GETVERSIONEX   0   /* GetVersionEx() is deprecated */
+#  else
+#    define SQLITE_WIN32_GETVERSIONEX   1   /* GetVersionEx() is current */
+#  endif
+#endif
+
+/*
+** Check to see if the CreateFileMappingA function is supported on the
+** target system.  It is unavailable when using "mincore.lib" on Win10.
+** When compiling for Windows 10, always assume "mincore.lib" is in use.
+*/
+#ifndef SQLITE_WIN32_CREATEFILEMAPPINGA
+#  if defined(NTDDI_VERSION) && NTDDI_VERSION >= NTDDI_WINTHRESHOLD
+#    define SQLITE_WIN32_CREATEFILEMAPPINGA   0
+#  else
+#    define SQLITE_WIN32_CREATEFILEMAPPINGA   1
+#  endif
+#endif
+
+/*
+** This constant should already be defined (in the "WinDef.h" SDK file).
+*/
+#ifndef MAX_PATH
+#  define MAX_PATH                      (260)
+#endif
+
+/*
+** Maximum pathname length (in chars) for Win32.  This should normally be
+** MAX_PATH.
+*/
+#ifndef SQLITE_WIN32_MAX_PATH_CHARS
+#  define SQLITE_WIN32_MAX_PATH_CHARS   (MAX_PATH)
+#endif
+
+/*
+** This constant should already be defined (in the "WinNT.h" SDK file).
+*/
+#ifndef UNICODE_STRING_MAX_CHARS
+#  define UNICODE_STRING_MAX_CHARS      (32767)
+#endif
+
+/*
+** Maximum pathname length (in chars) for WinNT.  This should normally be
+** UNICODE_STRING_MAX_CHARS.
+*/
+#ifndef SQLITE_WINNT_MAX_PATH_CHARS
+#  define SQLITE_WINNT_MAX_PATH_CHARS   (UNICODE_STRING_MAX_CHARS)
+#endif
+
+/*
+** Maximum pathname length (in bytes) for Win32.  The MAX_PATH macro is in
+** characters, so we allocate 4 bytes per character assuming worst-case of
+** 4-bytes-per-character for UTF8.
+*/
+#ifndef SQLITE_WIN32_MAX_PATH_BYTES
+#  define SQLITE_WIN32_MAX_PATH_BYTES   (SQLITE_WIN32_MAX_PATH_CHARS*4)
+#endif
+
+/*
+** Maximum pathname length (in bytes) for WinNT.  This should normally be
+** UNICODE_STRING_MAX_CHARS * sizeof(WCHAR).
+*/
+#ifndef SQLITE_WINNT_MAX_PATH_BYTES
+#  define SQLITE_WINNT_MAX_PATH_BYTES   \
+                            (sizeof(WCHAR) * SQLITE_WINNT_MAX_PATH_CHARS)
+#endif
+
+/*
+** Maximum error message length (in chars) for WinRT.
+*/
+#ifndef SQLITE_WIN32_MAX_ERRMSG_CHARS
+#  define SQLITE_WIN32_MAX_ERRMSG_CHARS (1024)
+#endif
+
+/*
+** Returns non-zero if the character should be treated as a directory
+** separator.
+*/
+#ifndef winIsDirSep
+#  define winIsDirSep(a)                (((a) == '/') || ((a) == '\\'))
+#endif
+
+/*
+** This macro is used when a local variable is set to a value that is
+** [sometimes] not used by the code (e.g. via conditional compilation).
+*/
+#ifndef UNUSED_VARIABLE_VALUE
+#  define UNUSED_VARIABLE_VALUE(x)      (void)(x)
+#endif
+
+/*
+** Returns the character that should be used as the directory separator.
+*/
+#ifndef winGetDirSep
+#  define winGetDirSep()                '\\'
+#endif
+
+/*
+** Do we need to manually define the Win32 file mapping APIs for use with WAL
+** mode or memory mapped files (e.g. these APIs are available in the Windows
+** CE SDK; however, they are not present in the header file)?
+*/
+#if SQLITE_WIN32_FILEMAPPING_API && \
+        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
+/*
+** Two of the file mapping APIs are different under WinRT.  Figure out which
+** set we need.
+*/
+#if SQLITE_OS_WINRT
+WINBASEAPI HANDLE WINAPI CreateFileMappingFromApp(HANDLE, \
+        LPSECURITY_ATTRIBUTES, ULONG, ULONG64, LPCWSTR);
+
+WINBASEAPI LPVOID WINAPI MapViewOfFileFromApp(HANDLE, ULONG, ULONG64, SIZE_T);
+#else
+#if defined(SQLITE_WIN32_HAS_ANSI)
+WINBASEAPI HANDLE WINAPI CreateFileMappingA(HANDLE, LPSECURITY_ATTRIBUTES, \
+        DWORD, DWORD, DWORD, LPCSTR);
+#endif /* defined(SQLITE_WIN32_HAS_ANSI) */
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+WINBASEAPI HANDLE WINAPI CreateFileMappingW(HANDLE, LPSECURITY_ATTRIBUTES, \
+        DWORD, DWORD, DWORD, LPCWSTR);
+#endif /* defined(SQLITE_WIN32_HAS_WIDE) */
+
+WINBASEAPI LPVOID WINAPI MapViewOfFile(HANDLE, DWORD, DWORD, DWORD, SIZE_T);
+#endif /* SQLITE_OS_WINRT */
+
+/*
+** These file mapping APIs are common to both Win32 and WinRT.
+*/
+
+WINBASEAPI BOOL WINAPI FlushViewOfFile(LPCVOID, SIZE_T);
+WINBASEAPI BOOL WINAPI UnmapViewOfFile(LPCVOID);
+#endif /* SQLITE_WIN32_FILEMAPPING_API */
+
+/*
+** Some Microsoft compilers lack this definition.
+*/
+#ifndef INVALID_FILE_ATTRIBUTES
+# define INVALID_FILE_ATTRIBUTES ((DWORD)-1)
+#endif
+
+#ifndef FILE_FLAG_MASK
+# define FILE_FLAG_MASK          (0xFF3C0000)
+#endif
+
+#ifndef FILE_ATTRIBUTE_MASK
+# define FILE_ATTRIBUTE_MASK     (0x0003FFF7)
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+/* Forward references to structures used for WAL */
+typedef struct winShm winShm;           /* A connection to shared-memory */
+typedef struct winShmNode winShmNode;   /* A region of shared-memory */
+#endif
+
+/*
+** WinCE lacks native support for file locking so we have to fake it
+** with some code of our own.
+*/
+#if SQLITE_OS_WINCE
+typedef struct winceLock {
+  int nReaders;       /* Number of reader locks obtained */
+  BOOL bPending;      /* Indicates a pending lock has been obtained */
+  BOOL bReserved;     /* Indicates a reserved lock has been obtained */
+  BOOL bExclusive;    /* Indicates an exclusive lock has been obtained */
+} winceLock;
+#endif
+
+/*
+** The winFile structure is a subclass of sqlite3_file* specific to the win32
+** portability layer.
+*/
+typedef struct winFile winFile;
+struct winFile {
+  const sqlite3_io_methods *pMethod; /*** Must be first ***/
+  sqlite3_vfs *pVfs;      /* The VFS used to open this file */
+  HANDLE h;               /* Handle for accessing the file */
+  u8 locktype;            /* Type of lock currently held on this file */
+  short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
+  u8 ctrlFlags;           /* Flags.  See WINFILE_* below */
+  DWORD lastErrno;        /* The Windows errno from the last I/O error */
+#ifndef SQLITE_OMIT_WAL
+  winShm *pShm;           /* Instance of shared memory on this file */
+#endif
+  const char *zPath;      /* Full pathname of this file */
+  int szChunk;            /* Chunk size configured by FCNTL_CHUNK_SIZE */
+#if SQLITE_OS_WINCE
+  LPWSTR zDeleteOnClose;  /* Name of file to delete when closing */
+  HANDLE hMutex;          /* Mutex used to control access to shared lock */
+  HANDLE hShared;         /* Shared memory segment used for locking */
+  winceLock local;        /* Locks obtained by this instance of winFile */
+  winceLock *shared;      /* Global shared lock memory for the file  */
+#endif
+#if SQLITE_MAX_MMAP_SIZE>0
+  int nFetchOut;                /* Number of outstanding xFetch references */
+  HANDLE hMap;                  /* Handle for accessing memory mapping */
+  void *pMapRegion;             /* Area memory mapped */
+  sqlite3_int64 mmapSize;       /* Size of mapped region */
+  sqlite3_int64 mmapSizeMax;    /* Configured FCNTL_MMAP_SIZE value */
+#endif
+};
+
+/*
+** The winVfsAppData structure is used for the pAppData member for all of the
+** Win32 VFS variants.
+*/
+typedef struct winVfsAppData winVfsAppData;
+struct winVfsAppData {
+  const sqlite3_io_methods *pMethod; /* The file I/O methods to use. */
+  void *pAppData;                    /* The extra pAppData, if any. */
+  BOOL bNoLock;                      /* Non-zero if locking is disabled. */
+};
+
+/*
+** Allowed values for winFile.ctrlFlags
+*/
+#define WINFILE_RDONLY          0x02   /* Connection is read only */
+#define WINFILE_PERSIST_WAL     0x04   /* Persistent WAL mode */
+#define WINFILE_PSOW            0x10   /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
+
+/*
+ * The size of the buffer used by sqlite3_win32_write_debug().
+ */
+#ifndef SQLITE_WIN32_DBG_BUF_SIZE
+#  define SQLITE_WIN32_DBG_BUF_SIZE   ((int)(4096-sizeof(DWORD)))
+#endif
+
+/*
+ * If compiled with SQLITE_WIN32_MALLOC on Windows, we will use the
+ * various Win32 API heap functions instead of our own.
+ */
+#ifdef SQLITE_WIN32_MALLOC
+
+/*
+ * If this is non-zero, an isolated heap will be created by the native Win32
+ * allocator subsystem; otherwise, the default process heap will be used.  This
+ * setting has no effect when compiling for WinRT.  By default, this is enabled
+ * and an isolated heap will be created to store all allocated data.
+ *
+ ******************************************************************************
+ * WARNING: It is important to note that when this setting is non-zero and the
+ *          winMemShutdown function is called (e.g. by the sqlite3_shutdown
+ *          function), all data that was allocated using the isolated heap will
+ *          be freed immediately and any attempt to access any of that freed
+ *          data will almost certainly result in an immediate access violation.
+ ******************************************************************************
+ */
+#ifndef SQLITE_WIN32_HEAP_CREATE
+#  define SQLITE_WIN32_HEAP_CREATE        (TRUE)
+#endif
+
+/*
+ * This is the maximum possible initial size of the Win32-specific heap, in
+ * bytes.
+ */
+#ifndef SQLITE_WIN32_HEAP_MAX_INIT_SIZE
+#  define SQLITE_WIN32_HEAP_MAX_INIT_SIZE (4294967295U)
+#endif
+
+/*
+ * This is the extra space for the initial size of the Win32-specific heap,
+ * in bytes.  This value may be zero.
+ */
+#ifndef SQLITE_WIN32_HEAP_INIT_EXTRA
+#  define SQLITE_WIN32_HEAP_INIT_EXTRA  (4194304)
+#endif
+
+/*
+ * Calculate the maximum legal cache size, in pages, based on the maximum
+ * possible initial heap size and the default page size, setting aside the
+ * needed extra space.
+ */
+#ifndef SQLITE_WIN32_MAX_CACHE_SIZE
+#  define SQLITE_WIN32_MAX_CACHE_SIZE   (((SQLITE_WIN32_HEAP_MAX_INIT_SIZE) - \
+                                          (SQLITE_WIN32_HEAP_INIT_EXTRA)) / \
+                                         (SQLITE_DEFAULT_PAGE_SIZE))
+#endif
+
+/*
+ * This is cache size used in the calculation of the initial size of the
+ * Win32-specific heap.  It cannot be negative.
+ */
+#ifndef SQLITE_WIN32_CACHE_SIZE
+#  if SQLITE_DEFAULT_CACHE_SIZE>=0
+#    define SQLITE_WIN32_CACHE_SIZE     (SQLITE_DEFAULT_CACHE_SIZE)
+#  else
+#    define SQLITE_WIN32_CACHE_SIZE     (-(SQLITE_DEFAULT_CACHE_SIZE))
+#  endif
+#endif
+
+/*
+ * Make sure that the calculated cache size, in pages, cannot cause the
+ * initial size of the Win32-specific heap to exceed the maximum amount
+ * of memory that can be specified in the call to HeapCreate.
+ */
+#if SQLITE_WIN32_CACHE_SIZE>SQLITE_WIN32_MAX_CACHE_SIZE
+#  undef SQLITE_WIN32_CACHE_SIZE
+#  define SQLITE_WIN32_CACHE_SIZE       (2000)
+#endif
+
+/*
+ * The initial size of the Win32-specific heap.  This value may be zero.
+ */
+#ifndef SQLITE_WIN32_HEAP_INIT_SIZE
+#  define SQLITE_WIN32_HEAP_INIT_SIZE   ((SQLITE_WIN32_CACHE_SIZE) * \
+                                         (SQLITE_DEFAULT_PAGE_SIZE) + \
+                                         (SQLITE_WIN32_HEAP_INIT_EXTRA))
+#endif
+
+/*
+ * The maximum size of the Win32-specific heap.  This value may be zero.
+ */
+#ifndef SQLITE_WIN32_HEAP_MAX_SIZE
+#  define SQLITE_WIN32_HEAP_MAX_SIZE    (0)
+#endif
+
+/*
+ * The extra flags to use in calls to the Win32 heap APIs.  This value may be
+ * zero for the default behavior.
+ */
+#ifndef SQLITE_WIN32_HEAP_FLAGS
+#  define SQLITE_WIN32_HEAP_FLAGS       (0)
+#endif
+
+
+/*
+** The winMemData structure stores information required by the Win32-specific
+** sqlite3_mem_methods implementation.
+*/
+typedef struct winMemData winMemData;
+struct winMemData {
+#ifndef NDEBUG
+  u32 magic1;   /* Magic number to detect structure corruption. */
+#endif
+  HANDLE hHeap; /* The handle to our heap. */
+  BOOL bOwned;  /* Do we own the heap (i.e. destroy it on shutdown)? */
+#ifndef NDEBUG
+  u32 magic2;   /* Magic number to detect structure corruption. */
+#endif
+};
+
+#ifndef NDEBUG
+#define WINMEM_MAGIC1     0x42b2830b
+#define WINMEM_MAGIC2     0xbd4d7cf4
+#endif
+
+static struct winMemData win_mem_data = {
+#ifndef NDEBUG
+  WINMEM_MAGIC1,
+#endif
+  NULL, FALSE
+#ifndef NDEBUG
+  ,WINMEM_MAGIC2
+#endif
+};
+
+#ifndef NDEBUG
+#define winMemAssertMagic1() assert( win_mem_data.magic1==WINMEM_MAGIC1 )
+#define winMemAssertMagic2() assert( win_mem_data.magic2==WINMEM_MAGIC2 )
+#define winMemAssertMagic()  winMemAssertMagic1(); winMemAssertMagic2();
+#else
+#define winMemAssertMagic()
+#endif
+
+#define winMemGetDataPtr()  &win_mem_data
+#define winMemGetHeap()     win_mem_data.hHeap
+#define winMemGetOwned()    win_mem_data.bOwned
+
+static void *winMemMalloc(int nBytes);
+static void winMemFree(void *pPrior);
+static void *winMemRealloc(void *pPrior, int nBytes);
+static int winMemSize(void *p);
+static int winMemRoundup(int n);
+static int winMemInit(void *pAppData);
+static void winMemShutdown(void *pAppData);
+
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetWin32(void);
+#endif /* SQLITE_WIN32_MALLOC */
+
+/*
+** The following variable is (normally) set once and never changes
+** thereafter.  It records whether the operating system is Win9x
+** or WinNT.
+**
+** 0:   Operating system unknown.
+** 1:   Operating system is Win9x.
+** 2:   Operating system is WinNT.
+**
+** In order to facilitate testing on a WinNT system, the test fixture
+** can manually set this value to 1 to emulate Win98 behavior.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API LONG SQLITE_WIN32_VOLATILE sqlite3_os_type = 0;
+#else
+static LONG SQLITE_WIN32_VOLATILE sqlite3_os_type = 0;
+#endif
+
+#ifndef SYSCALL
+#  define SYSCALL sqlite3_syscall_ptr
+#endif
+
+/*
+** This function is not available on Windows CE or WinRT.
+ */
+
+#if SQLITE_OS_WINCE || SQLITE_OS_WINRT
+#  define osAreFileApisANSI()       1
+#endif
+
+/*
+** Many system calls are accessed through pointer-to-functions so that
+** they may be overridden at runtime to facilitate fault injection during
+** testing and sandboxing.  The following array holds the names and pointers
+** to all overrideable system calls.
+*/
+static struct win_syscall {
+  const char *zName;            /* Name of the system call */
+  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
+  sqlite3_syscall_ptr pDefault; /* Default value */
+} aSyscall[] = {
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "AreFileApisANSI",         (SYSCALL)AreFileApisANSI,         0 },
+#else
+  { "AreFileApisANSI",         (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osAreFileApisANSI
+#define osAreFileApisANSI ((BOOL(WINAPI*)(VOID))aSyscall[0].pCurrent)
+#endif
+
+#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CharLowerW",              (SYSCALL)CharLowerW,              0 },
+#else
+  { "CharLowerW",              (SYSCALL)0,                       0 },
+#endif
+
+#define osCharLowerW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[1].pCurrent)
+
+#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CharUpperW",              (SYSCALL)CharUpperW,              0 },
+#else
+  { "CharUpperW",              (SYSCALL)0,                       0 },
+#endif
+
+#define osCharUpperW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[2].pCurrent)
+
+  { "CloseHandle",             (SYSCALL)CloseHandle,             0 },
+
+#define osCloseHandle ((BOOL(WINAPI*)(HANDLE))aSyscall[3].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "CreateFileA",             (SYSCALL)CreateFileA,             0 },
+#else
+  { "CreateFileA",             (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileA ((HANDLE(WINAPI*)(LPCSTR,DWORD,DWORD, \
+        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[4].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CreateFileW",             (SYSCALL)CreateFileW,             0 },
+#else
+  { "CreateFileW",             (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileW ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD, \
+        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[5].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_ANSI) && \
+        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0) && \
+        SQLITE_WIN32_CREATEFILEMAPPINGA
+  { "CreateFileMappingA",      (SYSCALL)CreateFileMappingA,      0 },
+#else
+  { "CreateFileMappingA",      (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileMappingA ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
+        DWORD,DWORD,DWORD,LPCSTR))aSyscall[6].pCurrent)
+
+#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
+        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0))
+  { "CreateFileMappingW",      (SYSCALL)CreateFileMappingW,      0 },
+#else
+  { "CreateFileMappingW",      (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileMappingW ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
+        DWORD,DWORD,DWORD,LPCWSTR))aSyscall[7].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CreateMutexW",            (SYSCALL)CreateMutexW,            0 },
+#else
+  { "CreateMutexW",            (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateMutexW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,BOOL, \
+        LPCWSTR))aSyscall[8].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "DeleteFileA",             (SYSCALL)DeleteFileA,             0 },
+#else
+  { "DeleteFileA",             (SYSCALL)0,                       0 },
+#endif
+
+#define osDeleteFileA ((BOOL(WINAPI*)(LPCSTR))aSyscall[9].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "DeleteFileW",             (SYSCALL)DeleteFileW,             0 },
+#else
+  { "DeleteFileW",             (SYSCALL)0,                       0 },
+#endif
+
+#define osDeleteFileW ((BOOL(WINAPI*)(LPCWSTR))aSyscall[10].pCurrent)
+
+#if SQLITE_OS_WINCE
+  { "FileTimeToLocalFileTime", (SYSCALL)FileTimeToLocalFileTime, 0 },
+#else
+  { "FileTimeToLocalFileTime", (SYSCALL)0,                       0 },
+#endif
+
+#define osFileTimeToLocalFileTime ((BOOL(WINAPI*)(CONST FILETIME*, \
+        LPFILETIME))aSyscall[11].pCurrent)
+
+#if SQLITE_OS_WINCE
+  { "FileTimeToSystemTime",    (SYSCALL)FileTimeToSystemTime,    0 },
+#else
+  { "FileTimeToSystemTime",    (SYSCALL)0,                       0 },
+#endif
+
+#define osFileTimeToSystemTime ((BOOL(WINAPI*)(CONST FILETIME*, \
+        LPSYSTEMTIME))aSyscall[12].pCurrent)
+
+  { "FlushFileBuffers",        (SYSCALL)FlushFileBuffers,        0 },
+
+#define osFlushFileBuffers ((BOOL(WINAPI*)(HANDLE))aSyscall[13].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "FormatMessageA",          (SYSCALL)FormatMessageA,          0 },
+#else
+  { "FormatMessageA",          (SYSCALL)0,                       0 },
+#endif
+
+#define osFormatMessageA ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPSTR, \
+        DWORD,va_list*))aSyscall[14].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "FormatMessageW",          (SYSCALL)FormatMessageW,          0 },
+#else
+  { "FormatMessageW",          (SYSCALL)0,                       0 },
+#endif
+
+#define osFormatMessageW ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPWSTR, \
+        DWORD,va_list*))aSyscall[15].pCurrent)
+
+#if !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  { "FreeLibrary",             (SYSCALL)FreeLibrary,             0 },
+#else
+  { "FreeLibrary",             (SYSCALL)0,                       0 },
+#endif
+
+#define osFreeLibrary ((BOOL(WINAPI*)(HMODULE))aSyscall[16].pCurrent)
+
+  { "GetCurrentProcessId",     (SYSCALL)GetCurrentProcessId,     0 },
+
+#define osGetCurrentProcessId ((DWORD(WINAPI*)(VOID))aSyscall[17].pCurrent)
+
+#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetDiskFreeSpaceA",       (SYSCALL)GetDiskFreeSpaceA,       0 },
+#else
+  { "GetDiskFreeSpaceA",       (SYSCALL)0,                       0 },
+#endif
+
+#define osGetDiskFreeSpaceA ((BOOL(WINAPI*)(LPCSTR,LPDWORD,LPDWORD,LPDWORD, \
+        LPDWORD))aSyscall[18].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetDiskFreeSpaceW",       (SYSCALL)GetDiskFreeSpaceW,       0 },
+#else
+  { "GetDiskFreeSpaceW",       (SYSCALL)0,                       0 },
+#endif
+
+#define osGetDiskFreeSpaceW ((BOOL(WINAPI*)(LPCWSTR,LPDWORD,LPDWORD,LPDWORD, \
+        LPDWORD))aSyscall[19].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetFileAttributesA",      (SYSCALL)GetFileAttributesA,      0 },
+#else
+  { "GetFileAttributesA",      (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileAttributesA ((DWORD(WINAPI*)(LPCSTR))aSyscall[20].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetFileAttributesW",      (SYSCALL)GetFileAttributesW,      0 },
+#else
+  { "GetFileAttributesW",      (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileAttributesW ((DWORD(WINAPI*)(LPCWSTR))aSyscall[21].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetFileAttributesExW",    (SYSCALL)GetFileAttributesExW,    0 },
+#else
+  { "GetFileAttributesExW",    (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileAttributesExW ((BOOL(WINAPI*)(LPCWSTR,GET_FILEEX_INFO_LEVELS, \
+        LPVOID))aSyscall[22].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "GetFileSize",             (SYSCALL)GetFileSize,             0 },
+#else
+  { "GetFileSize",             (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileSize ((DWORD(WINAPI*)(HANDLE,LPDWORD))aSyscall[23].pCurrent)
+
+#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetFullPathNameA",        (SYSCALL)GetFullPathNameA,        0 },
+#else
+  { "GetFullPathNameA",        (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFullPathNameA ((DWORD(WINAPI*)(LPCSTR,DWORD,LPSTR, \
+        LPSTR*))aSyscall[24].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetFullPathNameW",        (SYSCALL)GetFullPathNameW,        0 },
+#else
+  { "GetFullPathNameW",        (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFullPathNameW ((DWORD(WINAPI*)(LPCWSTR,DWORD,LPWSTR, \
+        LPWSTR*))aSyscall[25].pCurrent)
+
+  { "GetLastError",            (SYSCALL)GetLastError,            0 },
+
+#define osGetLastError ((DWORD(WINAPI*)(VOID))aSyscall[26].pCurrent)
+
+#if !defined(SQLITE_OMIT_LOAD_EXTENSION)
+#if SQLITE_OS_WINCE
+  /* The GetProcAddressA() routine is only available on Windows CE. */
+  { "GetProcAddressA",         (SYSCALL)GetProcAddressA,         0 },
+#else
+  /* All other Windows platforms expect GetProcAddress() to take
+  ** an ANSI string regardless of the _UNICODE setting */
+  { "GetProcAddressA",         (SYSCALL)GetProcAddress,          0 },
+#endif
+#else
+  { "GetProcAddressA",         (SYSCALL)0,                       0 },
+#endif
+
+#define osGetProcAddressA ((FARPROC(WINAPI*)(HMODULE, \
+        LPCSTR))aSyscall[27].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "GetSystemInfo",           (SYSCALL)GetSystemInfo,           0 },
+#else
+  { "GetSystemInfo",           (SYSCALL)0,                       0 },
+#endif
+
+#define osGetSystemInfo ((VOID(WINAPI*)(LPSYSTEM_INFO))aSyscall[28].pCurrent)
+
+  { "GetSystemTime",           (SYSCALL)GetSystemTime,           0 },
+
+#define osGetSystemTime ((VOID(WINAPI*)(LPSYSTEMTIME))aSyscall[29].pCurrent)
+
+#if !SQLITE_OS_WINCE
+  { "GetSystemTimeAsFileTime", (SYSCALL)GetSystemTimeAsFileTime, 0 },
+#else
+  { "GetSystemTimeAsFileTime", (SYSCALL)0,                       0 },
+#endif
+
+#define osGetSystemTimeAsFileTime ((VOID(WINAPI*)( \
+        LPFILETIME))aSyscall[30].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetTempPathA",            (SYSCALL)GetTempPathA,            0 },
+#else
+  { "GetTempPathA",            (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTempPathA ((DWORD(WINAPI*)(DWORD,LPSTR))aSyscall[31].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetTempPathW",            (SYSCALL)GetTempPathW,            0 },
+#else
+  { "GetTempPathW",            (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTempPathW ((DWORD(WINAPI*)(DWORD,LPWSTR))aSyscall[32].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "GetTickCount",            (SYSCALL)GetTickCount,            0 },
+#else
+  { "GetTickCount",            (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTickCount ((DWORD(WINAPI*)(VOID))aSyscall[33].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI) && SQLITE_WIN32_GETVERSIONEX
+  { "GetVersionExA",           (SYSCALL)GetVersionExA,           0 },
+#else
+  { "GetVersionExA",           (SYSCALL)0,                       0 },
+#endif
+
+#define osGetVersionExA ((BOOL(WINAPI*)( \
+        LPOSVERSIONINFOA))aSyscall[34].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
+        SQLITE_WIN32_GETVERSIONEX
+  { "GetVersionExW",           (SYSCALL)GetVersionExW,           0 },
+#else
+  { "GetVersionExW",           (SYSCALL)0,                       0 },
+#endif
+
+#define osGetVersionExW ((BOOL(WINAPI*)( \
+        LPOSVERSIONINFOW))aSyscall[35].pCurrent)
+
+  { "HeapAlloc",               (SYSCALL)HeapAlloc,               0 },
+
+#define osHeapAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD, \
+        SIZE_T))aSyscall[36].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "HeapCreate",              (SYSCALL)HeapCreate,              0 },
+#else
+  { "HeapCreate",              (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapCreate ((HANDLE(WINAPI*)(DWORD,SIZE_T, \
+        SIZE_T))aSyscall[37].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "HeapDestroy",             (SYSCALL)HeapDestroy,             0 },
+#else
+  { "HeapDestroy",             (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapDestroy ((BOOL(WINAPI*)(HANDLE))aSyscall[38].pCurrent)
+
+  { "HeapFree",                (SYSCALL)HeapFree,                0 },
+
+#define osHeapFree ((BOOL(WINAPI*)(HANDLE,DWORD,LPVOID))aSyscall[39].pCurrent)
+
+  { "HeapReAlloc",             (SYSCALL)HeapReAlloc,             0 },
+
+#define osHeapReAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD,LPVOID, \
+        SIZE_T))aSyscall[40].pCurrent)
+
+  { "HeapSize",                (SYSCALL)HeapSize,                0 },
+
+#define osHeapSize ((SIZE_T(WINAPI*)(HANDLE,DWORD, \
+        LPCVOID))aSyscall[41].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "HeapValidate",            (SYSCALL)HeapValidate,            0 },
+#else
+  { "HeapValidate",            (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapValidate ((BOOL(WINAPI*)(HANDLE,DWORD, \
+        LPCVOID))aSyscall[42].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "HeapCompact",             (SYSCALL)HeapCompact,             0 },
+#else
+  { "HeapCompact",             (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapCompact ((UINT(WINAPI*)(HANDLE,DWORD))aSyscall[43].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  { "LoadLibraryA",            (SYSCALL)LoadLibraryA,            0 },
+#else
+  { "LoadLibraryA",            (SYSCALL)0,                       0 },
+#endif
+
+#define osLoadLibraryA ((HMODULE(WINAPI*)(LPCSTR))aSyscall[44].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
+        !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  { "LoadLibraryW",            (SYSCALL)LoadLibraryW,            0 },
+#else
+  { "LoadLibraryW",            (SYSCALL)0,                       0 },
+#endif
+
+#define osLoadLibraryW ((HMODULE(WINAPI*)(LPCWSTR))aSyscall[45].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "LocalFree",               (SYSCALL)LocalFree,               0 },
+#else
+  { "LocalFree",               (SYSCALL)0,                       0 },
+#endif
+
+#define osLocalFree ((HLOCAL(WINAPI*)(HLOCAL))aSyscall[46].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "LockFile",                (SYSCALL)LockFile,                0 },
+#else
+  { "LockFile",                (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osLockFile
+#define osLockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        DWORD))aSyscall[47].pCurrent)
+#endif
+
+#if !SQLITE_OS_WINCE
+  { "LockFileEx",              (SYSCALL)LockFileEx,              0 },
+#else
+  { "LockFileEx",              (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osLockFileEx
+#define osLockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD,DWORD, \
+        LPOVERLAPPED))aSyscall[48].pCurrent)
+#endif
+
+#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && \
+        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0))
+  { "MapViewOfFile",           (SYSCALL)MapViewOfFile,           0 },
+#else
+  { "MapViewOfFile",           (SYSCALL)0,                       0 },
+#endif
+
+#define osMapViewOfFile ((LPVOID(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        SIZE_T))aSyscall[49].pCurrent)
+
+  { "MultiByteToWideChar",     (SYSCALL)MultiByteToWideChar,     0 },
+
+#define osMultiByteToWideChar ((int(WINAPI*)(UINT,DWORD,LPCSTR,int,LPWSTR, \
+        int))aSyscall[50].pCurrent)
+
+  { "QueryPerformanceCounter", (SYSCALL)QueryPerformanceCounter, 0 },
+
+#define osQueryPerformanceCounter ((BOOL(WINAPI*)( \
+        LARGE_INTEGER*))aSyscall[51].pCurrent)
+
+  { "ReadFile",                (SYSCALL)ReadFile,                0 },
+
+#define osReadFile ((BOOL(WINAPI*)(HANDLE,LPVOID,DWORD,LPDWORD, \
+        LPOVERLAPPED))aSyscall[52].pCurrent)
+
+  { "SetEndOfFile",            (SYSCALL)SetEndOfFile,            0 },
+
+#define osSetEndOfFile ((BOOL(WINAPI*)(HANDLE))aSyscall[53].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "SetFilePointer",          (SYSCALL)SetFilePointer,          0 },
+#else
+  { "SetFilePointer",          (SYSCALL)0,                       0 },
+#endif
+
+#define osSetFilePointer ((DWORD(WINAPI*)(HANDLE,LONG,PLONG, \
+        DWORD))aSyscall[54].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "Sleep",                   (SYSCALL)Sleep,                   0 },
+#else
+  { "Sleep",                   (SYSCALL)0,                       0 },
+#endif
+
+#define osSleep ((VOID(WINAPI*)(DWORD))aSyscall[55].pCurrent)
+
+  { "SystemTimeToFileTime",    (SYSCALL)SystemTimeToFileTime,    0 },
+
+#define osSystemTimeToFileTime ((BOOL(WINAPI*)(CONST SYSTEMTIME*, \
+        LPFILETIME))aSyscall[56].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "UnlockFile",              (SYSCALL)UnlockFile,              0 },
+#else
+  { "UnlockFile",              (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osUnlockFile
+#define osUnlockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        DWORD))aSyscall[57].pCurrent)
+#endif
+
+#if !SQLITE_OS_WINCE
+  { "UnlockFileEx",            (SYSCALL)UnlockFileEx,            0 },
+#else
+  { "UnlockFileEx",            (SYSCALL)0,                       0 },
+#endif
+
+#define osUnlockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        LPOVERLAPPED))aSyscall[58].pCurrent)
+
+#if SQLITE_OS_WINCE || !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
+  { "UnmapViewOfFile",         (SYSCALL)UnmapViewOfFile,         0 },
+#else
+  { "UnmapViewOfFile",         (SYSCALL)0,                       0 },
+#endif
+
+#define osUnmapViewOfFile ((BOOL(WINAPI*)(LPCVOID))aSyscall[59].pCurrent)
+
+  { "WideCharToMultiByte",     (SYSCALL)WideCharToMultiByte,     0 },
+
+#define osWideCharToMultiByte ((int(WINAPI*)(UINT,DWORD,LPCWSTR,int,LPSTR,int, \
+        LPCSTR,LPBOOL))aSyscall[60].pCurrent)
+
+  { "WriteFile",               (SYSCALL)WriteFile,               0 },
+
+#define osWriteFile ((BOOL(WINAPI*)(HANDLE,LPCVOID,DWORD,LPDWORD, \
+        LPOVERLAPPED))aSyscall[61].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "CreateEventExW",          (SYSCALL)CreateEventExW,          0 },
+#else
+  { "CreateEventExW",          (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateEventExW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,LPCWSTR, \
+        DWORD,DWORD))aSyscall[62].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "WaitForSingleObject",     (SYSCALL)WaitForSingleObject,     0 },
+#else
+  { "WaitForSingleObject",     (SYSCALL)0,                       0 },
+#endif
+
+#define osWaitForSingleObject ((DWORD(WINAPI*)(HANDLE, \
+        DWORD))aSyscall[63].pCurrent)
+
+#if !SQLITE_OS_WINCE
+  { "WaitForSingleObjectEx",   (SYSCALL)WaitForSingleObjectEx,   0 },
+#else
+  { "WaitForSingleObjectEx",   (SYSCALL)0,                       0 },
+#endif
+
+#define osWaitForSingleObjectEx ((DWORD(WINAPI*)(HANDLE,DWORD, \
+        BOOL))aSyscall[64].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "SetFilePointerEx",        (SYSCALL)SetFilePointerEx,        0 },
+#else
+  { "SetFilePointerEx",        (SYSCALL)0,                       0 },
+#endif
+
+#define osSetFilePointerEx ((BOOL(WINAPI*)(HANDLE,LARGE_INTEGER, \
+        PLARGE_INTEGER,DWORD))aSyscall[65].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "GetFileInformationByHandleEx", (SYSCALL)GetFileInformationByHandleEx, 0 },
+#else
+  { "GetFileInformationByHandleEx", (SYSCALL)0,                  0 },
+#endif
+
+#define osGetFileInformationByHandleEx ((BOOL(WINAPI*)(HANDLE, \
+        FILE_INFO_BY_HANDLE_CLASS,LPVOID,DWORD))aSyscall[66].pCurrent)
+
+#if SQLITE_OS_WINRT && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
+  { "MapViewOfFileFromApp",    (SYSCALL)MapViewOfFileFromApp,    0 },
+#else
+  { "MapViewOfFileFromApp",    (SYSCALL)0,                       0 },
+#endif
+
+#define osMapViewOfFileFromApp ((LPVOID(WINAPI*)(HANDLE,ULONG,ULONG64, \
+        SIZE_T))aSyscall[67].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "CreateFile2",             (SYSCALL)CreateFile2,             0 },
+#else
+  { "CreateFile2",             (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFile2 ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD,DWORD, \
+        LPCREATEFILE2_EXTENDED_PARAMETERS))aSyscall[68].pCurrent)
+
+#if SQLITE_OS_WINRT && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  { "LoadPackagedLibrary",     (SYSCALL)LoadPackagedLibrary,     0 },
+#else
+  { "LoadPackagedLibrary",     (SYSCALL)0,                       0 },
+#endif
+
+#define osLoadPackagedLibrary ((HMODULE(WINAPI*)(LPCWSTR, \
+        DWORD))aSyscall[69].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "GetTickCount64",          (SYSCALL)GetTickCount64,          0 },
+#else
+  { "GetTickCount64",          (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTickCount64 ((ULONGLONG(WINAPI*)(VOID))aSyscall[70].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "GetNativeSystemInfo",     (SYSCALL)GetNativeSystemInfo,     0 },
+#else
+  { "GetNativeSystemInfo",     (SYSCALL)0,                       0 },
+#endif
+
+#define osGetNativeSystemInfo ((VOID(WINAPI*)( \
+        LPSYSTEM_INFO))aSyscall[71].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "OutputDebugStringA",      (SYSCALL)OutputDebugStringA,      0 },
+#else
+  { "OutputDebugStringA",      (SYSCALL)0,                       0 },
+#endif
+
+#define osOutputDebugStringA ((VOID(WINAPI*)(LPCSTR))aSyscall[72].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "OutputDebugStringW",      (SYSCALL)OutputDebugStringW,      0 },
+#else
+  { "OutputDebugStringW",      (SYSCALL)0,                       0 },
+#endif
+
+#define osOutputDebugStringW ((VOID(WINAPI*)(LPCWSTR))aSyscall[73].pCurrent)
+
+  { "GetProcessHeap",          (SYSCALL)GetProcessHeap,          0 },
+
+#define osGetProcessHeap ((HANDLE(WINAPI*)(VOID))aSyscall[74].pCurrent)
+
+#if SQLITE_OS_WINRT && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
+  { "CreateFileMappingFromApp", (SYSCALL)CreateFileMappingFromApp, 0 },
+#else
+  { "CreateFileMappingFromApp", (SYSCALL)0,                      0 },
+#endif
+
+#define osCreateFileMappingFromApp ((HANDLE(WINAPI*)(HANDLE, \
+        LPSECURITY_ATTRIBUTES,ULONG,ULONG64,LPCWSTR))aSyscall[75].pCurrent)
+
+/*
+** NOTE: On some sub-platforms, the InterlockedCompareExchange "function"
+**       is really just a macro that uses a compiler intrinsic (e.g. x64).
+**       So do not try to make this is into a redefinable interface.
+*/
+#if defined(InterlockedCompareExchange)
+  { "InterlockedCompareExchange", (SYSCALL)0,                    0 },
+
+#define osInterlockedCompareExchange InterlockedCompareExchange
+#else
+  { "InterlockedCompareExchange", (SYSCALL)InterlockedCompareExchange, 0 },
+
+#define osInterlockedCompareExchange ((LONG(WINAPI*)(LONG \
+        SQLITE_WIN32_VOLATILE*, LONG,LONG))aSyscall[76].pCurrent)
+#endif /* defined(InterlockedCompareExchange) */
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_WIN32_USE_UUID
+  { "UuidCreate",               (SYSCALL)UuidCreate,             0 },
+#else
+  { "UuidCreate",               (SYSCALL)0,                      0 },
+#endif
+
+#define osUuidCreate ((RPC_STATUS(RPC_ENTRY*)(UUID*))aSyscall[77].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_WIN32_USE_UUID
+  { "UuidCreateSequential",     (SYSCALL)UuidCreateSequential,   0 },
+#else
+  { "UuidCreateSequential",     (SYSCALL)0,                      0 },
+#endif
+
+#define osUuidCreateSequential \
+        ((RPC_STATUS(RPC_ENTRY*)(UUID*))aSyscall[78].pCurrent)
+
+#if !defined(SQLITE_NO_SYNC) && SQLITE_MAX_MMAP_SIZE>0
+  { "FlushViewOfFile",          (SYSCALL)FlushViewOfFile,        0 },
+#else
+  { "FlushViewOfFile",          (SYSCALL)0,                      0 },
+#endif
+
+#define osFlushViewOfFile \
+        ((BOOL(WINAPI*)(LPCVOID,SIZE_T))aSyscall[79].pCurrent)
+
+}; /* End of the overrideable system calls */
+
+/*
+** This is the xSetSystemCall() method of sqlite3_vfs for all of the
+** "win32" VFSes.  Return SQLITE_OK upon successfully updating the
+** system call pointer, or SQLITE_NOTFOUND if there is no configurable
+** system call named zName.
+*/
+static int winSetSystemCall(
+  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
+  const char *zName,            /* Name of system call to override */
+  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */
+){
+  unsigned int i;
+  int rc = SQLITE_NOTFOUND;
+
+  UNUSED_PARAMETER(pNotUsed);
+  if( zName==0 ){
+    /* If no zName is given, restore all system calls to their default
+    ** settings and return NULL
+    */
+    rc = SQLITE_OK;
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( aSyscall[i].pDefault ){
+        aSyscall[i].pCurrent = aSyscall[i].pDefault;
+      }
+    }
+  }else{
+    /* If zName is specified, operate on only the one system call
+    ** specified.
+    */
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ){
+        if( aSyscall[i].pDefault==0 ){
+          aSyscall[i].pDefault = aSyscall[i].pCurrent;
+        }
+        rc = SQLITE_OK;
+        if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault;
+        aSyscall[i].pCurrent = pNewFunc;
+        break;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the value of a system call.  Return NULL if zName is not a
+** recognized system call name.  NULL is also returned if the system call
+** is currently undefined.
+*/
+static sqlite3_syscall_ptr winGetSystemCall(
+  sqlite3_vfs *pNotUsed,
+  const char *zName
+){
+  unsigned int i;
+
+  UNUSED_PARAMETER(pNotUsed);
+  for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+    if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent;
+  }
+  return 0;
+}
+
+/*
+** Return the name of the first system call after zName.  If zName==NULL
+** then return the name of the first system call.  Return NULL if zName
+** is the last system call or if zName is not the name of a valid
+** system call.
+*/
+static const char *winNextSystemCall(sqlite3_vfs *p, const char *zName){
+  int i = -1;
+
+  UNUSED_PARAMETER(p);
+  if( zName ){
+    for(i=0; i<ArraySize(aSyscall)-1; i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ) break;
+    }
+  }
+  for(i++; i<ArraySize(aSyscall); i++){
+    if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName;
+  }
+  return 0;
+}
+
+#ifdef SQLITE_WIN32_MALLOC
+/*
+** If a Win32 native heap has been configured, this function will attempt to
+** compact it.  Upon success, SQLITE_OK will be returned.  Upon failure, one
+** of SQLITE_NOMEM, SQLITE_ERROR, or SQLITE_NOTFOUND will be returned.  The
+** "pnLargest" argument, if non-zero, will be used to return the size of the
+** largest committed free block in the heap, in bytes.
+*/
+SQLITE_API int sqlite3_win32_compact_heap(LPUINT pnLargest){
+  int rc = SQLITE_OK;
+  UINT nLargest = 0;
+  HANDLE hHeap;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  if( (nLargest=osHeapCompact(hHeap, SQLITE_WIN32_HEAP_FLAGS))==0 ){
+    DWORD lastErrno = osGetLastError();
+    if( lastErrno==NO_ERROR ){
+      sqlite3_log(SQLITE_NOMEM, "failed to HeapCompact (no space), heap=%p",
+                  (void*)hHeap);
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      sqlite3_log(SQLITE_ERROR, "failed to HeapCompact (%lu), heap=%p",
+                  osGetLastError(), (void*)hHeap);
+      rc = SQLITE_ERROR;
+    }
+  }
+#else
+  sqlite3_log(SQLITE_NOTFOUND, "failed to HeapCompact, heap=%p",
+              (void*)hHeap);
+  rc = SQLITE_NOTFOUND;
+#endif
+  if( pnLargest ) *pnLargest = nLargest;
+  return rc;
+}
+
+/*
+** If a Win32 native heap has been configured, this function will attempt to
+** destroy and recreate it.  If the Win32 native heap is not isolated and/or
+** the sqlite3_memory_used() function does not return zero, SQLITE_BUSY will
+** be returned and no changes will be made to the Win32 native heap.
+*/
+SQLITE_API int sqlite3_win32_reset_heap(){
+  int rc;
+  MUTEX_LOGIC( sqlite3_mutex *pMainMtx; ) /* The main static mutex */
+  MUTEX_LOGIC( sqlite3_mutex *pMem; )    /* The memsys static mutex */
+  MUTEX_LOGIC( pMainMtx = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  MUTEX_LOGIC( pMem = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM); )
+  sqlite3_mutex_enter(pMainMtx);
+  sqlite3_mutex_enter(pMem);
+  winMemAssertMagic();
+  if( winMemGetHeap()!=NULL && winMemGetOwned() && sqlite3_memory_used()==0 ){
+    /*
+    ** At this point, there should be no outstanding memory allocations on
+    ** the heap.  Also, since both the main and memsys locks are currently
+    ** being held by us, no other function (i.e. from another thread) should
+    ** be able to even access the heap.  Attempt to destroy and recreate our
+    ** isolated Win32 native heap now.
+    */
+    assert( winMemGetHeap()!=NULL );
+    assert( winMemGetOwned() );
+    assert( sqlite3_memory_used()==0 );
+    winMemShutdown(winMemGetDataPtr());
+    assert( winMemGetHeap()==NULL );
+    assert( !winMemGetOwned() );
+    assert( sqlite3_memory_used()==0 );
+    rc = winMemInit(winMemGetDataPtr());
+    assert( rc!=SQLITE_OK || winMemGetHeap()!=NULL );
+    assert( rc!=SQLITE_OK || winMemGetOwned() );
+    assert( rc!=SQLITE_OK || sqlite3_memory_used()==0 );
+  }else{
+    /*
+    ** The Win32 native heap cannot be modified because it may be in use.
+    */
+    rc = SQLITE_BUSY;
+  }
+  sqlite3_mutex_leave(pMem);
+  sqlite3_mutex_leave(pMainMtx);
+  return rc;
+}
+#endif /* SQLITE_WIN32_MALLOC */
+
+/*
+** This function outputs the specified (ANSI) string to the Win32 debugger
+** (if available).
+*/
+
+SQLITE_API void sqlite3_win32_write_debug(const char *zBuf, int nBuf){
+  char zDbgBuf[SQLITE_WIN32_DBG_BUF_SIZE];
+  int nMin = MIN(nBuf, (SQLITE_WIN32_DBG_BUF_SIZE - 1)); /* may be negative. */
+  if( nMin<-1 ) nMin = -1; /* all negative values become -1. */
+  assert( nMin==-1 || nMin==0 || nMin<SQLITE_WIN32_DBG_BUF_SIZE );
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zBuf ){
+    (void)SQLITE_MISUSE_BKPT;
+    return;
+  }
+#endif
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  if( nMin>0 ){
+    memset(zDbgBuf, 0, SQLITE_WIN32_DBG_BUF_SIZE);
+    memcpy(zDbgBuf, zBuf, nMin);
+    osOutputDebugStringA(zDbgBuf);
+  }else{
+    osOutputDebugStringA(zBuf);
+  }
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+  memset(zDbgBuf, 0, SQLITE_WIN32_DBG_BUF_SIZE);
+  if ( osMultiByteToWideChar(
+          osAreFileApisANSI() ? CP_ACP : CP_OEMCP, 0, zBuf,
+          nMin, (LPWSTR)zDbgBuf, SQLITE_WIN32_DBG_BUF_SIZE/sizeof(WCHAR))<=0 ){
+    return;
+  }
+  osOutputDebugStringW((LPCWSTR)zDbgBuf);
+#else
+  if( nMin>0 ){
+    memset(zDbgBuf, 0, SQLITE_WIN32_DBG_BUF_SIZE);
+    memcpy(zDbgBuf, zBuf, nMin);
+    fprintf(stderr, "%s", zDbgBuf);
+  }else{
+    fprintf(stderr, "%s", zBuf);
+  }
+#endif
+}
+
+/*
+** The following routine suspends the current thread for at least ms
+** milliseconds.  This is equivalent to the Win32 Sleep() interface.
+*/
+#if SQLITE_OS_WINRT
+static HANDLE sleepObj = NULL;
+#endif
+
+SQLITE_API void sqlite3_win32_sleep(DWORD milliseconds){
+#if SQLITE_OS_WINRT
+  if ( sleepObj==NULL ){
+    sleepObj = osCreateEventExW(NULL, NULL, CREATE_EVENT_MANUAL_RESET,
+                                SYNCHRONIZE);
+  }
+  assert( sleepObj!=NULL );
+  osWaitForSingleObjectEx(sleepObj, milliseconds, FALSE);
+#else
+  osSleep(milliseconds);
+#endif
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0 && !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && \
+        SQLITE_THREADSAFE>0
+SQLITE_PRIVATE DWORD sqlite3Win32Wait(HANDLE hObject){
+  DWORD rc;
+  while( (rc = osWaitForSingleObjectEx(hObject, INFINITE,
+                                       TRUE))==WAIT_IO_COMPLETION ){}
+  return rc;
+}
+#endif
+
+/*
+** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
+** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
+**
+** Here is an interesting observation:  Win95, Win98, and WinME lack
+** the LockFileEx() API.  But we can still statically link against that
+** API as long as we don't call it when running Win95/98/ME.  A call to
+** this routine is used to determine if the host is Win95/98/ME or
+** WinNT/2K/XP so that we will know whether or not we can safely call
+** the LockFileEx() API.
+*/
+
+#if !SQLITE_WIN32_GETVERSIONEX
+# define osIsNT()  (1)
+#elif SQLITE_OS_WINCE || SQLITE_OS_WINRT || !defined(SQLITE_WIN32_HAS_ANSI)
+# define osIsNT()  (1)
+#elif !defined(SQLITE_WIN32_HAS_WIDE)
+# define osIsNT()  (0)
+#else
+# define osIsNT()  ((sqlite3_os_type==2) || sqlite3_win32_is_nt())
+#endif
+
+/*
+** This function determines if the machine is running a version of Windows
+** based on the NT kernel.
+*/
+SQLITE_API int sqlite3_win32_is_nt(void){
+#if SQLITE_OS_WINRT
+  /*
+  ** NOTE: The WinRT sub-platform is always assumed to be based on the NT
+  **       kernel.
+  */
+  return 1;
+#elif SQLITE_WIN32_GETVERSIONEX
+  if( osInterlockedCompareExchange(&sqlite3_os_type, 0, 0)==0 ){
+#if defined(SQLITE_WIN32_HAS_ANSI)
+    OSVERSIONINFOA sInfo;
+    sInfo.dwOSVersionInfoSize = sizeof(sInfo);
+    osGetVersionExA(&sInfo);
+    osInterlockedCompareExchange(&sqlite3_os_type,
+        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+    OSVERSIONINFOW sInfo;
+    sInfo.dwOSVersionInfoSize = sizeof(sInfo);
+    osGetVersionExW(&sInfo);
+    osInterlockedCompareExchange(&sqlite3_os_type,
+        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
+#endif
+  }
+  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
+#elif SQLITE_TEST
+  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
+#else
+  /*
+  ** NOTE: All sub-platforms where the GetVersionEx[AW] functions are
+  **       deprecated are always assumed to be based on the NT kernel.
+  */
+  return 1;
+#endif
+}
+
+#ifdef SQLITE_WIN32_MALLOC
+/*
+** Allocate nBytes of memory.
+*/
+static void *winMemMalloc(int nBytes){
+  HANDLE hHeap;
+  void *p;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+  assert( nBytes>=0 );
+  p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
+  if( !p ){
+    sqlite3_log(SQLITE_NOMEM, "failed to HeapAlloc %u bytes (%lu), heap=%p",
+                nBytes, osGetLastError(), (void*)hHeap);
+  }
+  return p;
+}
+
+/*
+** Free memory.
+*/
+static void winMemFree(void *pPrior){
+  HANDLE hHeap;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
+#endif
+  if( !pPrior ) return; /* Passing NULL to HeapFree is undefined. */
+  if( !osHeapFree(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) ){
+    sqlite3_log(SQLITE_NOMEM, "failed to HeapFree block %p (%lu), heap=%p",
+                pPrior, osGetLastError(), (void*)hHeap);
+  }
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+static void *winMemRealloc(void *pPrior, int nBytes){
+  HANDLE hHeap;
+  void *p;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
+#endif
+  assert( nBytes>=0 );
+  if( !pPrior ){
+    p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
+  }else{
+    p = osHeapReAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior, (SIZE_T)nBytes);
+  }
+  if( !p ){
+    sqlite3_log(SQLITE_NOMEM, "failed to %s %u bytes (%lu), heap=%p",
+                pPrior ? "HeapReAlloc" : "HeapAlloc", nBytes, osGetLastError(),
+                (void*)hHeap);
+  }
+  return p;
+}
+
+/*
+** Return the size of an outstanding allocation, in bytes.
+*/
+static int winMemSize(void *p){
+  HANDLE hHeap;
+  SIZE_T n;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, p) );
+#endif
+  if( !p ) return 0;
+  n = osHeapSize(hHeap, SQLITE_WIN32_HEAP_FLAGS, p);
+  if( n==(SIZE_T)-1 ){
+    sqlite3_log(SQLITE_NOMEM, "failed to HeapSize block %p (%lu), heap=%p",
+                p, osGetLastError(), (void*)hHeap);
+    return 0;
+  }
+  return (int)n;
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int winMemRoundup(int n){
+  return n;
+}
+
+/*
+** Initialize this module.
+*/
+static int winMemInit(void *pAppData){
+  winMemData *pWinMemData = (winMemData *)pAppData;
+
+  if( !pWinMemData ) return SQLITE_ERROR;
+  assert( pWinMemData->magic1==WINMEM_MAGIC1 );
+  assert( pWinMemData->magic2==WINMEM_MAGIC2 );
+
+#if !SQLITE_OS_WINRT && SQLITE_WIN32_HEAP_CREATE
+  if( !pWinMemData->hHeap ){
+    DWORD dwInitialSize = SQLITE_WIN32_HEAP_INIT_SIZE;
+    DWORD dwMaximumSize = (DWORD)sqlite3GlobalConfig.nHeap;
+    if( dwMaximumSize==0 ){
+      dwMaximumSize = SQLITE_WIN32_HEAP_MAX_SIZE;
+    }else if( dwInitialSize>dwMaximumSize ){
+      dwInitialSize = dwMaximumSize;
+    }
+    pWinMemData->hHeap = osHeapCreate(SQLITE_WIN32_HEAP_FLAGS,
+                                      dwInitialSize, dwMaximumSize);
+    if( !pWinMemData->hHeap ){
+      sqlite3_log(SQLITE_NOMEM,
+          "failed to HeapCreate (%lu), flags=%u, initSize=%lu, maxSize=%lu",
+          osGetLastError(), SQLITE_WIN32_HEAP_FLAGS, dwInitialSize,
+          dwMaximumSize);
+      return SQLITE_NOMEM_BKPT;
+    }
+    pWinMemData->bOwned = TRUE;
+    assert( pWinMemData->bOwned );
+  }
+#else
+  pWinMemData->hHeap = osGetProcessHeap();
+  if( !pWinMemData->hHeap ){
+    sqlite3_log(SQLITE_NOMEM,
+        "failed to GetProcessHeap (%lu)", osGetLastError());
+    return SQLITE_NOMEM_BKPT;
+  }
+  pWinMemData->bOwned = FALSE;
+  assert( !pWinMemData->bOwned );
+#endif
+  assert( pWinMemData->hHeap!=0 );
+  assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize this module.
+*/
+static void winMemShutdown(void *pAppData){
+  winMemData *pWinMemData = (winMemData *)pAppData;
+
+  if( !pWinMemData ) return;
+  assert( pWinMemData->magic1==WINMEM_MAGIC1 );
+  assert( pWinMemData->magic2==WINMEM_MAGIC2 );
+
+  if( pWinMemData->hHeap ){
+    assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+    assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+    if( pWinMemData->bOwned ){
+      if( !osHeapDestroy(pWinMemData->hHeap) ){
+        sqlite3_log(SQLITE_NOMEM, "failed to HeapDestroy (%lu), heap=%p",
+                    osGetLastError(), (void*)pWinMemData->hHeap);
+      }
+      pWinMemData->bOwned = FALSE;
+    }
+    pWinMemData->hHeap = NULL;
+  }
+}
+
+/*
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file. The
+** arguments specify the block of memory to manage.
+**
+** This routine is only called by sqlite3_config(), and therefore
+** is not required to be threadsafe (it is not).
+*/
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetWin32(void){
+  static const sqlite3_mem_methods winMemMethods = {
+    winMemMalloc,
+    winMemFree,
+    winMemRealloc,
+    winMemSize,
+    winMemRoundup,
+    winMemInit,
+    winMemShutdown,
+    &win_mem_data
+  };
+  return &winMemMethods;
+}
+
+SQLITE_PRIVATE void sqlite3MemSetDefault(void){
+  sqlite3_config(SQLITE_CONFIG_MALLOC, sqlite3MemGetWin32());
+}
+#endif /* SQLITE_WIN32_MALLOC */
+
+/*
+** Convert a UTF-8 string to Microsoft Unicode.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static LPWSTR winUtf8ToUnicode(const char *zText){
+  int nChar;
+  LPWSTR zWideText;
+
+  nChar = osMultiByteToWideChar(CP_UTF8, 0, zText, -1, NULL, 0);
+  if( nChar==0 ){
+    return 0;
+  }
+  zWideText = sqlite3MallocZero( nChar*sizeof(WCHAR) );
+  if( zWideText==0 ){
+    return 0;
+  }
+  nChar = osMultiByteToWideChar(CP_UTF8, 0, zText, -1, zWideText,
+                                nChar);
+  if( nChar==0 ){
+    sqlite3_free(zWideText);
+    zWideText = 0;
+  }
+  return zWideText;
+}
+
+/*
+** Convert a Microsoft Unicode string to UTF-8.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static char *winUnicodeToUtf8(LPCWSTR zWideText){
+  int nByte;
+  char *zText;
+
+  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideText, -1, 0, 0, 0, 0);
+  if( nByte == 0 ){
+    return 0;
+  }
+  zText = sqlite3MallocZero( nByte );
+  if( zText==0 ){
+    return 0;
+  }
+  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideText, -1, zText, nByte,
+                                0, 0);
+  if( nByte == 0 ){
+    sqlite3_free(zText);
+    zText = 0;
+  }
+  return zText;
+}
+
+/*
+** Convert an ANSI string to Microsoft Unicode, using the ANSI or OEM
+** code page.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static LPWSTR winMbcsToUnicode(const char *zText, int useAnsi){
+  int nByte;
+  LPWSTR zMbcsText;
+  int codepage = useAnsi ? CP_ACP : CP_OEMCP;
+
+  nByte = osMultiByteToWideChar(codepage, 0, zText, -1, NULL,
+                                0)*sizeof(WCHAR);
+  if( nByte==0 ){
+    return 0;
+  }
+  zMbcsText = sqlite3MallocZero( nByte*sizeof(WCHAR) );
+  if( zMbcsText==0 ){
+    return 0;
+  }
+  nByte = osMultiByteToWideChar(codepage, 0, zText, -1, zMbcsText,
+                                nByte);
+  if( nByte==0 ){
+    sqlite3_free(zMbcsText);
+    zMbcsText = 0;
+  }
+  return zMbcsText;
+}
+
+/*
+** Convert a Microsoft Unicode string to a multi-byte character string,
+** using the ANSI or OEM code page.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static char *winUnicodeToMbcs(LPCWSTR zWideText, int useAnsi){
+  int nByte;
+  char *zText;
+  int codepage = useAnsi ? CP_ACP : CP_OEMCP;
+
+  nByte = osWideCharToMultiByte(codepage, 0, zWideText, -1, 0, 0, 0, 0);
+  if( nByte == 0 ){
+    return 0;
+  }
+  zText = sqlite3MallocZero( nByte );
+  if( zText==0 ){
+    return 0;
+  }
+  nByte = osWideCharToMultiByte(codepage, 0, zWideText, -1, zText,
+                                nByte, 0, 0);
+  if( nByte == 0 ){
+    sqlite3_free(zText);
+    zText = 0;
+  }
+  return zText;
+}
+
+/*
+** Convert a multi-byte character string to UTF-8.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static char *winMbcsToUtf8(const char *zText, int useAnsi){
+  char *zTextUtf8;
+  LPWSTR zTmpWide;
+
+  zTmpWide = winMbcsToUnicode(zText, useAnsi);
+  if( zTmpWide==0 ){
+    return 0;
+  }
+  zTextUtf8 = winUnicodeToUtf8(zTmpWide);
+  sqlite3_free(zTmpWide);
+  return zTextUtf8;
+}
+
+/*
+** Convert a UTF-8 string to a multi-byte character string.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static char *winUtf8ToMbcs(const char *zText, int useAnsi){
+  char *zTextMbcs;
+  LPWSTR zTmpWide;
+
+  zTmpWide = winUtf8ToUnicode(zText);
+  if( zTmpWide==0 ){
+    return 0;
+  }
+  zTextMbcs = winUnicodeToMbcs(zTmpWide, useAnsi);
+  sqlite3_free(zTmpWide);
+  return zTextMbcs;
+}
+
+/*
+** This is a public wrapper for the winUtf8ToUnicode() function.
+*/
+SQLITE_API LPWSTR sqlite3_win32_utf8_to_unicode(const char *zText){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winUtf8ToUnicode(zText);
+}
+
+/*
+** This is a public wrapper for the winUnicodeToUtf8() function.
+*/
+SQLITE_API char *sqlite3_win32_unicode_to_utf8(LPCWSTR zWideText){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zWideText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winUnicodeToUtf8(zWideText);
+}
+
+/*
+** This is a public wrapper for the winMbcsToUtf8() function.
+*/
+SQLITE_API char *sqlite3_win32_mbcs_to_utf8(const char *zText){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winMbcsToUtf8(zText, osAreFileApisANSI());
+}
+
+/*
+** This is a public wrapper for the winMbcsToUtf8() function.
+*/
+SQLITE_API char *sqlite3_win32_mbcs_to_utf8_v2(const char *zText, int useAnsi){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winMbcsToUtf8(zText, useAnsi);
+}
+
+/*
+** This is a public wrapper for the winUtf8ToMbcs() function.
+*/
+SQLITE_API char *sqlite3_win32_utf8_to_mbcs(const char *zText){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winUtf8ToMbcs(zText, osAreFileApisANSI());
+}
+
+/*
+** This is a public wrapper for the winUtf8ToMbcs() function.
+*/
+SQLITE_API char *sqlite3_win32_utf8_to_mbcs_v2(const char *zText, int useAnsi){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winUtf8ToMbcs(zText, useAnsi);
+}
+
+/*
+** This function is the same as sqlite3_win32_set_directory (below); however,
+** it accepts a UTF-8 string.
+*/
+SQLITE_API int sqlite3_win32_set_directory8(
+  unsigned long type, /* Identifier for directory being set or reset */
+  const char *zValue  /* New value for directory being set or reset */
+){
+  char **ppDirectory = 0;
+  int rc;
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  if( type==SQLITE_WIN32_DATA_DIRECTORY_TYPE ){
+    ppDirectory = &sqlite3_data_directory;
+  }else if( type==SQLITE_WIN32_TEMP_DIRECTORY_TYPE ){
+    ppDirectory = &sqlite3_temp_directory;
+  }
+  assert( !ppDirectory || type==SQLITE_WIN32_DATA_DIRECTORY_TYPE
+          || type==SQLITE_WIN32_TEMP_DIRECTORY_TYPE
+  );
+  assert( !ppDirectory || sqlite3MemdebugHasType(*ppDirectory, MEMTYPE_HEAP) );
+  if( ppDirectory ){
+    char *zCopy = 0;
+    if( zValue && zValue[0] ){
+      zCopy = sqlite3_mprintf("%s", zValue);
+      if ( zCopy==0 ){
+        rc = SQLITE_NOMEM_BKPT;
+        goto set_directory8_done;
+      }
+    }
+    sqlite3_free(*ppDirectory);
+    *ppDirectory = zCopy;
+    rc = SQLITE_OK;
+  }else{
+    rc = SQLITE_ERROR;
+  }
+set_directory8_done:
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return rc;
+}
+
+/*
+** This function is the same as sqlite3_win32_set_directory (below); however,
+** it accepts a UTF-16 string.
+*/
+SQLITE_API int sqlite3_win32_set_directory16(
+  unsigned long type, /* Identifier for directory being set or reset */
+  const void *zValue  /* New value for directory being set or reset */
+){
+  int rc;
+  char *zUtf8 = 0;
+  if( zValue ){
+    zUtf8 = sqlite3_win32_unicode_to_utf8(zValue);
+    if( zUtf8==0 ) return SQLITE_NOMEM_BKPT;
+  }
+  rc = sqlite3_win32_set_directory8(type, zUtf8);
+  if( zUtf8 ) sqlite3_free(zUtf8);
+  return rc;
+}
+
+/*
+** This function sets the data directory or the temporary directory based on
+** the provided arguments.  The type argument must be 1 in order to set the
+** data directory or 2 in order to set the temporary directory.  The zValue
+** argument is the name of the directory to use.  The return value will be
+** SQLITE_OK if successful.
+*/
+SQLITE_API int sqlite3_win32_set_directory(
+  unsigned long type, /* Identifier for directory being set or reset */
+  void *zValue        /* New value for directory being set or reset */
+){
+  return sqlite3_win32_set_directory16(type, zValue);
+}
+
+/*
+** The return value of winGetLastErrorMsg
+** is zero if the error message fits in the buffer, or non-zero
+** otherwise (if the message was truncated).
+*/
+static int winGetLastErrorMsg(DWORD lastErrno, int nBuf, char *zBuf){
+  /* FormatMessage returns 0 on failure.  Otherwise it
+  ** returns the number of TCHARs written to the output
+  ** buffer, excluding the terminating null char.
+  */
+  DWORD dwLen = 0;
+  char *zOut = 0;
+
+  if( osIsNT() ){
+#if SQLITE_OS_WINRT
+    WCHAR zTempWide[SQLITE_WIN32_MAX_ERRMSG_CHARS+1];
+    dwLen = osFormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL,
+                             lastErrno,
+                             0,
+                             zTempWide,
+                             SQLITE_WIN32_MAX_ERRMSG_CHARS,
+                             0);
+#else
+    LPWSTR zTempWide = NULL;
+    dwLen = osFormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                             FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL,
+                             lastErrno,
+                             0,
+                             (LPWSTR) &zTempWide,
+                             0,
+                             0);
+#endif
+    if( dwLen > 0 ){
+      /* allocate a buffer and convert to UTF8 */
+      sqlite3BeginBenignMalloc();
+      zOut = winUnicodeToUtf8(zTempWide);
+      sqlite3EndBenignMalloc();
+#if !SQLITE_OS_WINRT
+      /* free the system buffer allocated by FormatMessage */
+      osLocalFree(zTempWide);
+#endif
+    }
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    char *zTemp = NULL;
+    dwLen = osFormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                             FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL,
+                             lastErrno,
+                             0,
+                             (LPSTR) &zTemp,
+                             0,
+                             0);
+    if( dwLen > 0 ){
+      /* allocate a buffer and convert to UTF8 */
+      sqlite3BeginBenignMalloc();
+      zOut = winMbcsToUtf8(zTemp, osAreFileApisANSI());
+      sqlite3EndBenignMalloc();
+      /* free the system buffer allocated by FormatMessage */
+      osLocalFree(zTemp);
+    }
+  }
+#endif
+  if( 0 == dwLen ){
+    sqlite3_snprintf(nBuf, zBuf, "OsError 0x%lx (%lu)", lastErrno, lastErrno);
+  }else{
+    /* copy a maximum of nBuf chars to output buffer */
+    sqlite3_snprintf(nBuf, zBuf, "%s", zOut);
+    /* free the UTF8 buffer */
+    sqlite3_free(zOut);
+  }
+  return 0;
+}
+
+/*
+**
+** This function - winLogErrorAtLine() - is only ever called via the macro
+** winLogError().
+**
+** This routine is invoked after an error occurs in an OS function.
+** It logs a message using sqlite3_log() containing the current value of
+** error code and, if possible, the human-readable equivalent from
+** FormatMessage.
+**
+** The first argument passed to the macro should be the error code that
+** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN).
+** The two subsequent arguments should be the name of the OS function that
+** failed and the associated file-system path, if any.
+*/
+#define winLogError(a,b,c,d)   winLogErrorAtLine(a,b,c,d,__LINE__)
+static int winLogErrorAtLine(
+  int errcode,                    /* SQLite error code */
+  DWORD lastErrno,                /* Win32 last error */
+  const char *zFunc,              /* Name of OS function that failed */
+  const char *zPath,              /* File path associated with error */
+  int iLine                       /* Source line number where error occurred */
+){
+  char zMsg[500];                 /* Human readable error text */
+  int i;                          /* Loop counter */
+
+  zMsg[0] = 0;
+  winGetLastErrorMsg(lastErrno, sizeof(zMsg), zMsg);
+  assert( errcode!=SQLITE_OK );
+  if( zPath==0 ) zPath = "";
+  for(i=0; zMsg[i] && zMsg[i]!='\r' && zMsg[i]!='\n'; i++){}
+  zMsg[i] = 0;
+  sqlite3_log(errcode,
+      "os_win.c:%d: (%lu) %s(%s) - %s",
+      iLine, lastErrno, zFunc, zPath, zMsg
+  );
+
+  return errcode;
+}
+
+/*
+** The number of times that a ReadFile(), WriteFile(), and DeleteFile()
+** will be retried following a locking error - probably caused by
+** antivirus software.  Also the initial delay before the first retry.
+** The delay increases linearly with each retry.
+*/
+#ifndef SQLITE_WIN32_IOERR_RETRY
+# define SQLITE_WIN32_IOERR_RETRY 10
+#endif
+#ifndef SQLITE_WIN32_IOERR_RETRY_DELAY
+# define SQLITE_WIN32_IOERR_RETRY_DELAY 25
+#endif
+static int winIoerrRetry = SQLITE_WIN32_IOERR_RETRY;
+static int winIoerrRetryDelay = SQLITE_WIN32_IOERR_RETRY_DELAY;
+
+/*
+** The "winIoerrCanRetry1" macro is used to determine if a particular I/O
+** error code obtained via GetLastError() is eligible to be retried.  It
+** must accept the error code DWORD as its only argument and should return
+** non-zero if the error code is transient in nature and the operation
+** responsible for generating the original error might succeed upon being
+** retried.  The argument to this macro should be a variable.
+**
+** Additionally, a macro named "winIoerrCanRetry2" may be defined.  If it
+** is defined, it will be consulted only when the macro "winIoerrCanRetry1"
+** returns zero.  The "winIoerrCanRetry2" macro is completely optional and
+** may be used to include additional error codes in the set that should
+** result in the failing I/O operation being retried by the caller.  If
+** defined, the "winIoerrCanRetry2" macro must exhibit external semantics
+** identical to those of the "winIoerrCanRetry1" macro.
+*/
+#if !defined(winIoerrCanRetry1)
+#define winIoerrCanRetry1(a) (((a)==ERROR_ACCESS_DENIED)        || \
+                              ((a)==ERROR_SHARING_VIOLATION)    || \
+                              ((a)==ERROR_LOCK_VIOLATION)       || \
+                              ((a)==ERROR_DEV_NOT_EXIST)        || \
+                              ((a)==ERROR_NETNAME_DELETED)      || \
+                              ((a)==ERROR_SEM_TIMEOUT)          || \
+                              ((a)==ERROR_NETWORK_UNREACHABLE))
+#endif
+
+/*
+** If a ReadFile() or WriteFile() error occurs, invoke this routine
+** to see if it should be retried.  Return TRUE to retry.  Return FALSE
+** to give up with an error.
+*/
+static int winRetryIoerr(int *pnRetry, DWORD *pError){
+  DWORD e = osGetLastError();
+  if( *pnRetry>=winIoerrRetry ){
+    if( pError ){
+      *pError = e;
+    }
+    return 0;
+  }
+  if( winIoerrCanRetry1(e) ){
+    sqlite3_win32_sleep(winIoerrRetryDelay*(1+*pnRetry));
+    ++*pnRetry;
+    return 1;
+  }
+#if defined(winIoerrCanRetry2)
+  else if( winIoerrCanRetry2(e) ){
+    sqlite3_win32_sleep(winIoerrRetryDelay*(1+*pnRetry));
+    ++*pnRetry;
+    return 1;
+  }
+#endif
+  if( pError ){
+    *pError = e;
+  }
+  return 0;
+}
+
+/*
+** Log a I/O error retry episode.
+*/
+static void winLogIoerr(int nRetry, int lineno){
+  if( nRetry ){
+    sqlite3_log(SQLITE_NOTICE,
+      "delayed %dms for lock/sharing conflict at line %d",
+      winIoerrRetryDelay*nRetry*(nRetry+1)/2, lineno
+    );
+  }
+}
+
+/*
+** This #if does not rely on the SQLITE_OS_WINCE define because the
+** corresponding section in "date.c" cannot use it.
+*/
+#if !defined(SQLITE_OMIT_LOCALTIME) && defined(_WIN32_WCE) && \
+    (!defined(SQLITE_MSVC_LOCALTIME_API) || !SQLITE_MSVC_LOCALTIME_API)
+/*
+** The MSVC CRT on Windows CE may not have a localtime() function.
+** So define a substitute.
+*/
+/* #  include <time.h> */
+struct tm *__cdecl localtime(const time_t *t)
+{
+  static struct tm y;
+  FILETIME uTm, lTm;
+  SYSTEMTIME pTm;
+  sqlite3_int64 t64;
+  t64 = *t;
+  t64 = (t64 + 11644473600)*10000000;
+  uTm.dwLowDateTime = (DWORD)(t64 & 0xFFFFFFFF);
+  uTm.dwHighDateTime= (DWORD)(t64 >> 32);
+  osFileTimeToLocalFileTime(&uTm,&lTm);
+  osFileTimeToSystemTime(&lTm,&pTm);
+  y.tm_year = pTm.wYear - 1900;
+  y.tm_mon = pTm.wMonth - 1;
+  y.tm_wday = pTm.wDayOfWeek;
+  y.tm_mday = pTm.wDay;
+  y.tm_hour = pTm.wHour;
+  y.tm_min = pTm.wMinute;
+  y.tm_sec = pTm.wSecond;
+  return &y;
+}
+#endif
+
+#if SQLITE_OS_WINCE
+/*************************************************************************
+** This section contains code for WinCE only.
+*/
+#define HANDLE_TO_WINFILE(a) (winFile*)&((char*)a)[-(int)offsetof(winFile,h)]
+
+/*
+** Acquire a lock on the handle h
+*/
+static void winceMutexAcquire(HANDLE h){
+   DWORD dwErr;
+   do {
+     dwErr = osWaitForSingleObject(h, INFINITE);
+   } while (dwErr != WAIT_OBJECT_0 && dwErr != WAIT_ABANDONED);
+}
+/*
+** Release a lock acquired by winceMutexAcquire()
+*/
+#define winceMutexRelease(h) ReleaseMutex(h)
+
+/*
+** Create the mutex and shared memory used for locking in the file
+** descriptor pFile
+*/
+static int winceCreateLock(const char *zFilename, winFile *pFile){
+  LPWSTR zTok;
+  LPWSTR zName;
+  DWORD lastErrno;
+  BOOL bLogged = FALSE;
+  BOOL bInit = TRUE;
+
+  zName = winUtf8ToUnicode(zFilename);
+  if( zName==0 ){
+    /* out of memory */
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+
+  /* Initialize the local lockdata */
+  memset(&pFile->local, 0, sizeof(pFile->local));
+
+  /* Replace the backslashes from the filename and lowercase it
+  ** to derive a mutex name. */
+  zTok = osCharLowerW(zName);
+  for (;*zTok;zTok++){
+    if (*zTok == '\\') *zTok = '_';
+  }
+
+  /* Create/open the named mutex */
+  pFile->hMutex = osCreateMutexW(NULL, FALSE, zName);
+  if (!pFile->hMutex){
+    pFile->lastErrno = osGetLastError();
+    sqlite3_free(zName);
+    return winLogError(SQLITE_IOERR, pFile->lastErrno,
+                       "winceCreateLock1", zFilename);
+  }
+
+  /* Acquire the mutex before continuing */
+  winceMutexAcquire(pFile->hMutex);
+
+  /* Since the names of named mutexes, semaphores, file mappings etc are
+  ** case-sensitive, take advantage of that by uppercasing the mutex name
+  ** and using that as the shared filemapping name.
+  */
+  osCharUpperW(zName);
+  pFile->hShared = osCreateFileMappingW(INVALID_HANDLE_VALUE, NULL,
+                                        PAGE_READWRITE, 0, sizeof(winceLock),
+                                        zName);
+
+  /* Set a flag that indicates we're the first to create the memory so it
+  ** must be zero-initialized */
+  lastErrno = osGetLastError();
+  if (lastErrno == ERROR_ALREADY_EXISTS){
+    bInit = FALSE;
+  }
+
+  sqlite3_free(zName);
+
+  /* If we succeeded in making the shared memory handle, map it. */
+  if( pFile->hShared ){
+    pFile->shared = (winceLock*)osMapViewOfFile(pFile->hShared,
+             FILE_MAP_READ|FILE_MAP_WRITE, 0, 0, sizeof(winceLock));
+    /* If mapping failed, close the shared memory handle and erase it */
+    if( !pFile->shared ){
+      pFile->lastErrno = osGetLastError();
+      winLogError(SQLITE_IOERR, pFile->lastErrno,
+                  "winceCreateLock2", zFilename);
+      bLogged = TRUE;
+      osCloseHandle(pFile->hShared);
+      pFile->hShared = NULL;
+    }
+  }
+
+  /* If shared memory could not be created, then close the mutex and fail */
+  if( pFile->hShared==NULL ){
+    if( !bLogged ){
+      pFile->lastErrno = lastErrno;
+      winLogError(SQLITE_IOERR, pFile->lastErrno,
+                  "winceCreateLock3", zFilename);
+      bLogged = TRUE;
+    }
+    winceMutexRelease(pFile->hMutex);
+    osCloseHandle(pFile->hMutex);
+    pFile->hMutex = NULL;
+    return SQLITE_IOERR;
+  }
+
+  /* Initialize the shared memory if we're supposed to */
+  if( bInit ){
+    memset(pFile->shared, 0, sizeof(winceLock));
+  }
+
+  winceMutexRelease(pFile->hMutex);
+  return SQLITE_OK;
+}
+
+/*
+** Destroy the part of winFile that deals with wince locks
+*/
+static void winceDestroyLock(winFile *pFile){
+  if (pFile->hMutex){
+    /* Acquire the mutex */
+    winceMutexAcquire(pFile->hMutex);
+
+    /* The following blocks should probably assert in debug mode, but they
+       are to cleanup in case any locks remained open */
+    if (pFile->local.nReaders){
+      pFile->shared->nReaders --;
+    }
+    if (pFile->local.bReserved){
+      pFile->shared->bReserved = FALSE;
+    }
+    if (pFile->local.bPending){
+      pFile->shared->bPending = FALSE;
+    }
+    if (pFile->local.bExclusive){
+      pFile->shared->bExclusive = FALSE;
+    }
+
+    /* De-reference and close our copy of the shared memory handle */
+    osUnmapViewOfFile(pFile->shared);
+    osCloseHandle(pFile->hShared);
+
+    /* Done with the mutex */
+    winceMutexRelease(pFile->hMutex);
+    osCloseHandle(pFile->hMutex);
+    pFile->hMutex = NULL;
+  }
+}
+
+/*
+** An implementation of the LockFile() API of Windows for CE
+*/
+static BOOL winceLockFile(
+  LPHANDLE phFile,
+  DWORD dwFileOffsetLow,
+  DWORD dwFileOffsetHigh,
+  DWORD nNumberOfBytesToLockLow,
+  DWORD nNumberOfBytesToLockHigh
+){
+  winFile *pFile = HANDLE_TO_WINFILE(phFile);
+  BOOL bReturn = FALSE;
+
+  UNUSED_PARAMETER(dwFileOffsetHigh);
+  UNUSED_PARAMETER(nNumberOfBytesToLockHigh);
+
+  if (!pFile->hMutex) return TRUE;
+  winceMutexAcquire(pFile->hMutex);
+
+  /* Wanting an exclusive lock? */
+  if (dwFileOffsetLow == (DWORD)SHARED_FIRST
+       && nNumberOfBytesToLockLow == (DWORD)SHARED_SIZE){
+    if (pFile->shared->nReaders == 0 && pFile->shared->bExclusive == 0){
+       pFile->shared->bExclusive = TRUE;
+       pFile->local.bExclusive = TRUE;
+       bReturn = TRUE;
+    }
+  }
+
+  /* Want a read-only lock? */
+  else if (dwFileOffsetLow == (DWORD)SHARED_FIRST &&
+           nNumberOfBytesToLockLow == 1){
+    if (pFile->shared->bExclusive == 0){
+      pFile->local.nReaders ++;
+      if (pFile->local.nReaders == 1){
+        pFile->shared->nReaders ++;
+      }
+      bReturn = TRUE;
+    }
+  }
+
+  /* Want a pending lock? */
+  else if (dwFileOffsetLow == (DWORD)PENDING_BYTE
+           && nNumberOfBytesToLockLow == 1){
+    /* If no pending lock has been acquired, then acquire it */
+    if (pFile->shared->bPending == 0) {
+      pFile->shared->bPending = TRUE;
+      pFile->local.bPending = TRUE;
+      bReturn = TRUE;
+    }
+  }
+
+  /* Want a reserved lock? */
+  else if (dwFileOffsetLow == (DWORD)RESERVED_BYTE
+           && nNumberOfBytesToLockLow == 1){
+    if (pFile->shared->bReserved == 0) {
+      pFile->shared->bReserved = TRUE;
+      pFile->local.bReserved = TRUE;
+      bReturn = TRUE;
+    }
+  }
+
+  winceMutexRelease(pFile->hMutex);
+  return bReturn;
+}
+
+/*
+** An implementation of the UnlockFile API of Windows for CE
+*/
+static BOOL winceUnlockFile(
+  LPHANDLE phFile,
+  DWORD dwFileOffsetLow,
+  DWORD dwFileOffsetHigh,
+  DWORD nNumberOfBytesToUnlockLow,
+  DWORD nNumberOfBytesToUnlockHigh
+){
+  winFile *pFile = HANDLE_TO_WINFILE(phFile);
+  BOOL bReturn = FALSE;
+
+  UNUSED_PARAMETER(dwFileOffsetHigh);
+  UNUSED_PARAMETER(nNumberOfBytesToUnlockHigh);
+
+  if (!pFile->hMutex) return TRUE;
+  winceMutexAcquire(pFile->hMutex);
+
+  /* Releasing a reader lock or an exclusive lock */
+  if (dwFileOffsetLow == (DWORD)SHARED_FIRST){
+    /* Did we have an exclusive lock? */
+    if (pFile->local.bExclusive){
+      assert(nNumberOfBytesToUnlockLow == (DWORD)SHARED_SIZE);
+      pFile->local.bExclusive = FALSE;
+      pFile->shared->bExclusive = FALSE;
+      bReturn = TRUE;
+    }
+
+    /* Did we just have a reader lock? */
+    else if (pFile->local.nReaders){
+      assert(nNumberOfBytesToUnlockLow == (DWORD)SHARED_SIZE
+             || nNumberOfBytesToUnlockLow == 1);
+      pFile->local.nReaders --;
+      if (pFile->local.nReaders == 0)
+      {
+        pFile->shared->nReaders --;
+      }
+      bReturn = TRUE;
+    }
+  }
+
+  /* Releasing a pending lock */
+  else if (dwFileOffsetLow == (DWORD)PENDING_BYTE
+           && nNumberOfBytesToUnlockLow == 1){
+    if (pFile->local.bPending){
+      pFile->local.bPending = FALSE;
+      pFile->shared->bPending = FALSE;
+      bReturn = TRUE;
+    }
+  }
+  /* Releasing a reserved lock */
+  else if (dwFileOffsetLow == (DWORD)RESERVED_BYTE
+           && nNumberOfBytesToUnlockLow == 1){
+    if (pFile->local.bReserved) {
+      pFile->local.bReserved = FALSE;
+      pFile->shared->bReserved = FALSE;
+      bReturn = TRUE;
+    }
+  }
+
+  winceMutexRelease(pFile->hMutex);
+  return bReturn;
+}
+/*
+** End of the special code for wince
+*****************************************************************************/
+#endif /* SQLITE_OS_WINCE */
+
+/*
+** Lock a file region.
+*/
+static BOOL winLockFile(
+  LPHANDLE phFile,
+  DWORD flags,
+  DWORD offsetLow,
+  DWORD offsetHigh,
+  DWORD numBytesLow,
+  DWORD numBytesHigh
+){
+#if SQLITE_OS_WINCE
+  /*
+  ** NOTE: Windows CE is handled differently here due its lack of the Win32
+  **       API LockFile.
+  */
+  return winceLockFile(phFile, offsetLow, offsetHigh,
+                       numBytesLow, numBytesHigh);
+#else
+  if( osIsNT() ){
+    OVERLAPPED ovlp;
+    memset(&ovlp, 0, sizeof(OVERLAPPED));
+    ovlp.Offset = offsetLow;
+    ovlp.OffsetHigh = offsetHigh;
+    return osLockFileEx(*phFile, flags, 0, numBytesLow, numBytesHigh, &ovlp);
+  }else{
+    return osLockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
+                      numBytesHigh);
+  }
+#endif
+}
+
+/*
+** Unlock a file region.
+ */
+static BOOL winUnlockFile(
+  LPHANDLE phFile,
+  DWORD offsetLow,
+  DWORD offsetHigh,
+  DWORD numBytesLow,
+  DWORD numBytesHigh
+){
+#if SQLITE_OS_WINCE
+  /*
+  ** NOTE: Windows CE is handled differently here due its lack of the Win32
+  **       API UnlockFile.
+  */
+  return winceUnlockFile(phFile, offsetLow, offsetHigh,
+                         numBytesLow, numBytesHigh);
+#else
+  if( osIsNT() ){
+    OVERLAPPED ovlp;
+    memset(&ovlp, 0, sizeof(OVERLAPPED));
+    ovlp.Offset = offsetLow;
+    ovlp.OffsetHigh = offsetHigh;
+    return osUnlockFileEx(*phFile, 0, numBytesLow, numBytesHigh, &ovlp);
+  }else{
+    return osUnlockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
+                        numBytesHigh);
+  }
+#endif
+}
+
+/*****************************************************************************
+** The next group of routines implement the I/O methods specified
+** by the sqlite3_io_methods object.
+******************************************************************************/
+
+/*
+** Some Microsoft compilers lack this definition.
+*/
+#ifndef INVALID_SET_FILE_POINTER
+# define INVALID_SET_FILE_POINTER ((DWORD)-1)
+#endif
+
+/*
+** Move the current position of the file handle passed as the first
+** argument to offset iOffset within the file. If successful, return 0.
+** Otherwise, set pFile->lastErrno and return non-zero.
+*/
+static int winSeekFile(winFile *pFile, sqlite3_int64 iOffset){
+#if !SQLITE_OS_WINRT
+  LONG upperBits;                 /* Most sig. 32 bits of new offset */
+  LONG lowerBits;                 /* Least sig. 32 bits of new offset */
+  DWORD dwRet;                    /* Value returned by SetFilePointer() */
+  DWORD lastErrno;                /* Value returned by GetLastError() */
+
+  OSTRACE(("SEEK file=%p, offset=%lld\n", pFile->h, iOffset));
+
+  upperBits = (LONG)((iOffset>>32) & 0x7fffffff);
+  lowerBits = (LONG)(iOffset & 0xffffffff);
+
+  /* API oddity: If successful, SetFilePointer() returns a dword
+  ** containing the lower 32-bits of the new file-offset. Or, if it fails,
+  ** it returns INVALID_SET_FILE_POINTER. However according to MSDN,
+  ** INVALID_SET_FILE_POINTER may also be a valid new offset. So to determine
+  ** whether an error has actually occurred, it is also necessary to call
+  ** GetLastError().
+  */
+  dwRet = osSetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
+
+  if( (dwRet==INVALID_SET_FILE_POINTER
+      && ((lastErrno = osGetLastError())!=NO_ERROR)) ){
+    pFile->lastErrno = lastErrno;
+    winLogError(SQLITE_IOERR_SEEK, pFile->lastErrno,
+                "winSeekFile", pFile->zPath);
+    OSTRACE(("SEEK file=%p, rc=SQLITE_IOERR_SEEK\n", pFile->h));
+    return 1;
+  }
+
+  OSTRACE(("SEEK file=%p, rc=SQLITE_OK\n", pFile->h));
+  return 0;
+#else
+  /*
+  ** Same as above, except that this implementation works for WinRT.
+  */
+
+  LARGE_INTEGER x;                /* The new offset */
+  BOOL bRet;                      /* Value returned by SetFilePointerEx() */
+
+  x.QuadPart = iOffset;
+  bRet = osSetFilePointerEx(pFile->h, x, 0, FILE_BEGIN);
+
+  if(!bRet){
+    pFile->lastErrno = osGetLastError();
+    winLogError(SQLITE_IOERR_SEEK, pFile->lastErrno,
+                "winSeekFile", pFile->zPath);
+    OSTRACE(("SEEK file=%p, rc=SQLITE_IOERR_SEEK\n", pFile->h));
+    return 1;
+  }
+
+  OSTRACE(("SEEK file=%p, rc=SQLITE_OK\n", pFile->h));
+  return 0;
+#endif
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/* Forward references to VFS helper methods used for memory mapped files */
+static int winMapfile(winFile*, sqlite3_int64);
+static int winUnmapfile(winFile*);
+#endif
+
+/*
+** Close a file.
+**
+** It is reported that an attempt to close a handle might sometimes
+** fail.  This is a very unreasonable result, but Windows is notorious
+** for being unreasonable so I do not doubt that it might happen.  If
+** the close fails, we pause for 100 milliseconds and try again.  As
+** many as MX_CLOSE_ATTEMPT attempts to close the handle are made before
+** giving up and returning an error.
+*/
+#define MX_CLOSE_ATTEMPT 3
+static int winClose(sqlite3_file *id){
+  int rc, cnt = 0;
+  winFile *pFile = (winFile*)id;
+
+  assert( id!=0 );
+#ifndef SQLITE_OMIT_WAL
+  assert( pFile->pShm==0 );
+#endif
+  assert( pFile->h!=NULL && pFile->h!=INVALID_HANDLE_VALUE );
+  OSTRACE(("CLOSE pid=%lu, pFile=%p, file=%p\n",
+           osGetCurrentProcessId(), pFile, pFile->h));
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  winUnmapfile(pFile);
+#endif
+
+  do{
+    rc = osCloseHandle(pFile->h);
+    /* SimulateIOError( rc=0; cnt=MX_CLOSE_ATTEMPT; ); */
+  }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (sqlite3_win32_sleep(100), 1) );
+#if SQLITE_OS_WINCE
+#define WINCE_DELETION_ATTEMPTS 3
+  {
+    winVfsAppData *pAppData = (winVfsAppData*)pFile->pVfs->pAppData;
+    if( pAppData==NULL || !pAppData->bNoLock ){
+      winceDestroyLock(pFile);
+    }
+  }
+  if( pFile->zDeleteOnClose ){
+    int cnt = 0;
+    while(
+           osDeleteFileW(pFile->zDeleteOnClose)==0
+        && osGetFileAttributesW(pFile->zDeleteOnClose)!=0xffffffff
+        && cnt++ < WINCE_DELETION_ATTEMPTS
+    ){
+       sqlite3_win32_sleep(100);  /* Wait a little before trying again */
+    }
+    sqlite3_free(pFile->zDeleteOnClose);
+  }
+#endif
+  if( rc ){
+    pFile->h = NULL;
+  }
+  OpenCounter(-1);
+  OSTRACE(("CLOSE pid=%lu, pFile=%p, file=%p, rc=%s\n",
+           osGetCurrentProcessId(), pFile, pFile->h, rc ? "ok" : "failed"));
+  return rc ? SQLITE_OK
+            : winLogError(SQLITE_IOERR_CLOSE, osGetLastError(),
+                          "winClose", pFile->zPath);
+}
+
+/*
+** Read data from a file into a buffer.  Return SQLITE_OK if all
+** bytes were read successfully and SQLITE_IOERR if anything goes
+** wrong.
+*/
+static int winRead(
+  sqlite3_file *id,          /* File to read from */
+  void *pBuf,                /* Write content into this buffer */
+  int amt,                   /* Number of bytes to read */
+  sqlite3_int64 offset       /* Begin reading at this offset */
+){
+#if !SQLITE_OS_WINCE && !defined(SQLITE_WIN32_NO_OVERLAPPED)
+  OVERLAPPED overlapped;          /* The offset for ReadFile. */
+#endif
+  winFile *pFile = (winFile*)id;  /* file handle */
+  DWORD nRead;                    /* Number of bytes actually read from file */
+  int nRetry = 0;                 /* Number of retrys */
+
+  assert( id!=0 );
+  assert( amt>0 );
+  assert( offset>=0 );
+  SimulateIOError(return SQLITE_IOERR_READ);
+  OSTRACE(("READ pid=%lu, pFile=%p, file=%p, buffer=%p, amount=%d, "
+           "offset=%lld, lock=%d\n", osGetCurrentProcessId(), pFile,
+           pFile->h, pBuf, amt, offset, pFile->locktype));
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  /* Deal with as much of this read request as possible by transferring
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt);
+      OSTRACE(("READ-MMAP pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+               osGetCurrentProcessId(), pFile, pFile->h));
+      return SQLITE_OK;
+    }else{
+      int nCopy = (int)(pFile->mmapSize - offset);
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+#endif
+
+#if SQLITE_OS_WINCE || defined(SQLITE_WIN32_NO_OVERLAPPED)
+  if( winSeekFile(pFile, offset) ){
+    OSTRACE(("READ pid=%lu, pFile=%p, file=%p, rc=SQLITE_FULL\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return SQLITE_FULL;
+  }
+  while( !osReadFile(pFile->h, pBuf, amt, &nRead, 0) ){
+#else
+  memset(&overlapped, 0, sizeof(OVERLAPPED));
+  overlapped.Offset = (LONG)(offset & 0xffffffff);
+  overlapped.OffsetHigh = (LONG)((offset>>32) & 0x7fffffff);
+  while( !osReadFile(pFile->h, pBuf, amt, &nRead, &overlapped) &&
+         osGetLastError()!=ERROR_HANDLE_EOF ){
+#endif
+    DWORD lastErrno;
+    if( winRetryIoerr(&nRetry, &lastErrno) ) continue;
+    pFile->lastErrno = lastErrno;
+    OSTRACE(("READ pid=%lu, pFile=%p, file=%p, rc=SQLITE_IOERR_READ\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return winLogError(SQLITE_IOERR_READ, pFile->lastErrno,
+                       "winRead", pFile->zPath);
+  }
+  winLogIoerr(nRetry, __LINE__);
+  if( nRead<(DWORD)amt ){
+    /* Unread parts of the buffer must be zero-filled */
+    memset(&((char*)pBuf)[nRead], 0, amt-nRead);
+    OSTRACE(("READ pid=%lu, pFile=%p, file=%p, rc=SQLITE_IOERR_SHORT_READ\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return SQLITE_IOERR_SHORT_READ;
+  }
+
+  OSTRACE(("READ pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFile, pFile->h));
+  return SQLITE_OK;
+}
+
+/*
+** Write data from a buffer into a file.  Return SQLITE_OK on success
+** or some other error code on failure.
+*/
+static int winWrite(
+  sqlite3_file *id,               /* File to write into */
+  const void *pBuf,               /* The bytes to be written */
+  int amt,                        /* Number of bytes to write */
+  sqlite3_int64 offset            /* Offset into the file to begin writing at */
+){
+  int rc = 0;                     /* True if error has occurred, else false */
+  winFile *pFile = (winFile*)id;  /* File handle */
+  int nRetry = 0;                 /* Number of retries */
+
+  assert( amt>0 );
+  assert( pFile );
+  SimulateIOError(return SQLITE_IOERR_WRITE);
+  SimulateDiskfullError(return SQLITE_FULL);
+
+  OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, buffer=%p, amount=%d, "
+           "offset=%lld, lock=%d\n", osGetCurrentProcessId(), pFile,
+           pFile->h, pBuf, amt, offset, pFile->locktype));
+
+#if defined(SQLITE_MMAP_READWRITE) && SQLITE_MAX_MMAP_SIZE>0
+  /* Deal with as much of this write request as possible by transferring
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt);
+      OSTRACE(("WRITE-MMAP pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+               osGetCurrentProcessId(), pFile, pFile->h));
+      return SQLITE_OK;
+    }else{
+      int nCopy = (int)(pFile->mmapSize - offset);
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+#endif
+
+#if SQLITE_OS_WINCE || defined(SQLITE_WIN32_NO_OVERLAPPED)
+  rc = winSeekFile(pFile, offset);
+  if( rc==0 ){
+#else
+  {
+#endif
+#if !SQLITE_OS_WINCE && !defined(SQLITE_WIN32_NO_OVERLAPPED)
+    OVERLAPPED overlapped;        /* The offset for WriteFile. */
+#endif
+    u8 *aRem = (u8 *)pBuf;        /* Data yet to be written */
+    int nRem = amt;               /* Number of bytes yet to be written */
+    DWORD nWrite;                 /* Bytes written by each WriteFile() call */
+    DWORD lastErrno = NO_ERROR;   /* Value returned by GetLastError() */
+
+#if !SQLITE_OS_WINCE && !defined(SQLITE_WIN32_NO_OVERLAPPED)
+    memset(&overlapped, 0, sizeof(OVERLAPPED));
+    overlapped.Offset = (LONG)(offset & 0xffffffff);
+    overlapped.OffsetHigh = (LONG)((offset>>32) & 0x7fffffff);
+#endif
+
+    while( nRem>0 ){
+#if SQLITE_OS_WINCE || defined(SQLITE_WIN32_NO_OVERLAPPED)
+      if( !osWriteFile(pFile->h, aRem, nRem, &nWrite, 0) ){
+#else
+      if( !osWriteFile(pFile->h, aRem, nRem, &nWrite, &overlapped) ){
+#endif
+        if( winRetryIoerr(&nRetry, &lastErrno) ) continue;
+        break;
+      }
+      assert( nWrite==0 || nWrite<=(DWORD)nRem );
+      if( nWrite==0 || nWrite>(DWORD)nRem ){
+        lastErrno = osGetLastError();
+        break;
+      }
+#if !SQLITE_OS_WINCE && !defined(SQLITE_WIN32_NO_OVERLAPPED)
+      offset += nWrite;
+      overlapped.Offset = (LONG)(offset & 0xffffffff);
+      overlapped.OffsetHigh = (LONG)((offset>>32) & 0x7fffffff);
+#endif
+      aRem += nWrite;
+      nRem -= nWrite;
+    }
+    if( nRem>0 ){
+      pFile->lastErrno = lastErrno;
+      rc = 1;
+    }
+  }
+
+  if( rc ){
+    if(   ( pFile->lastErrno==ERROR_HANDLE_DISK_FULL )
+       || ( pFile->lastErrno==ERROR_DISK_FULL )){
+      OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, rc=SQLITE_FULL\n",
+               osGetCurrentProcessId(), pFile, pFile->h));
+      return winLogError(SQLITE_FULL, pFile->lastErrno,
+                         "winWrite1", pFile->zPath);
+    }
+    OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, rc=SQLITE_IOERR_WRITE\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return winLogError(SQLITE_IOERR_WRITE, pFile->lastErrno,
+                       "winWrite2", pFile->zPath);
+  }else{
+    winLogIoerr(nRetry, __LINE__);
+  }
+  OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFile, pFile->h));
+  return SQLITE_OK;
+}
+
+/*
+** Truncate an open file to a specified size
+*/
+static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
+  winFile *pFile = (winFile*)id;  /* File handle object */
+  int rc = SQLITE_OK;             /* Return code for this function */
+  DWORD lastErrno;
+#if SQLITE_MAX_MMAP_SIZE>0
+  sqlite3_int64 oldMmapSize;
+  if( pFile->nFetchOut>0 ){
+    /* File truncation is a no-op if there are outstanding memory mapped
+    ** pages.  This is because truncating the file means temporarily unmapping
+    ** the file, and that might delete memory out from under existing cursors.
+    **
+    ** This can result in incremental vacuum not truncating the file,
+    ** if there is an active read cursor when the incremental vacuum occurs.
+    ** No real harm comes of this - the database file is not corrupted,
+    ** though some folks might complain that the file is bigger than it
+    ** needs to be.
+    **
+    ** The only feasible work-around is to defer the truncation until after
+    ** all references to memory-mapped content are closed.  That is doable,
+    ** but involves adding a few branches in the common write code path which
+    ** could slow down normal operations slightly.  Hence, we have decided for
+    ** now to simply make transactions a no-op if there are pending reads.  We
+    ** can maybe revisit this decision in the future.
+    */
+    return SQLITE_OK;
+  }
+#endif
+
+  assert( pFile );
+  SimulateIOError(return SQLITE_IOERR_TRUNCATE);
+  OSTRACE(("TRUNCATE pid=%lu, pFile=%p, file=%p, size=%lld, lock=%d\n",
+           osGetCurrentProcessId(), pFile, pFile->h, nByte, pFile->locktype));
+
+  /* If the user has configured a chunk-size for this file, truncate the
+  ** file so that it consists of an integer number of chunks (i.e. the
+  ** actual file size after the operation may be larger than the requested
+  ** size).
+  */
+  if( pFile->szChunk>0 ){
+    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
+  }
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFile->pMapRegion ){
+    oldMmapSize = pFile->mmapSize;
+  }else{
+    oldMmapSize = 0;
+  }
+  winUnmapfile(pFile);
+#endif
+
+  /* SetEndOfFile() returns non-zero when successful, or zero when it fails. */
+  if( winSeekFile(pFile, nByte) ){
+    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
+                     "winTruncate1", pFile->zPath);
+  }else if( 0==osSetEndOfFile(pFile->h) &&
+            ((lastErrno = osGetLastError())!=ERROR_USER_MAPPED_FILE) ){
+    pFile->lastErrno = lastErrno;
+    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
+                     "winTruncate2", pFile->zPath);
+  }
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( rc==SQLITE_OK && oldMmapSize>0 ){
+    if( oldMmapSize>nByte ){
+      winMapfile(pFile, -1);
+    }else{
+      winMapfile(pFile, oldMmapSize);
+    }
+  }
+#endif
+
+  OSTRACE(("TRUNCATE pid=%lu, pFile=%p, file=%p, rc=%s\n",
+           osGetCurrentProcessId(), pFile, pFile->h, sqlite3ErrName(rc)));
+  return rc;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Count the number of fullsyncs and normal syncs.  This is used to test
+** that syncs and fullsyncs are occurring at the right times.
+*/
+SQLITE_API int sqlite3_sync_count = 0;
+SQLITE_API int sqlite3_fullsync_count = 0;
+#endif
+
+/*
+** Make sure all writes to a particular file are committed to disk.
+*/
+static int winSync(sqlite3_file *id, int flags){
+#ifndef SQLITE_NO_SYNC
+  /*
+  ** Used only when SQLITE_NO_SYNC is not defined.
+   */
+  BOOL rc;
+#endif
+#if !defined(NDEBUG) || !defined(SQLITE_NO_SYNC) || \
+    defined(SQLITE_HAVE_OS_TRACE)
+  /*
+  ** Used when SQLITE_NO_SYNC is not defined and by the assert() and/or
+  ** OSTRACE() macros.
+   */
+  winFile *pFile = (winFile*)id;
+#else
+  UNUSED_PARAMETER(id);
+#endif
+
+  assert( pFile );
+  /* Check that one of SQLITE_SYNC_NORMAL or FULL was passed */
+  assert((flags&0x0F)==SQLITE_SYNC_NORMAL
+      || (flags&0x0F)==SQLITE_SYNC_FULL
+  );
+
+  /* Unix cannot, but some systems may return SQLITE_FULL from here. This
+  ** line is to test that doing so does not cause any problems.
+  */
+  SimulateDiskfullError( return SQLITE_FULL );
+
+  OSTRACE(("SYNC pid=%lu, pFile=%p, file=%p, flags=%x, lock=%d\n",
+           osGetCurrentProcessId(), pFile, pFile->h, flags,
+           pFile->locktype));
+
+#ifndef SQLITE_TEST
+  UNUSED_PARAMETER(flags);
+#else
+  if( (flags&0x0F)==SQLITE_SYNC_FULL ){
+    sqlite3_fullsync_count++;
+  }
+  sqlite3_sync_count++;
+#endif
+
+  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
+  ** no-op
+  */
+#ifdef SQLITE_NO_SYNC
+  OSTRACE(("SYNC-NOP pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFile, pFile->h));
+  return SQLITE_OK;
+#else
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFile->pMapRegion ){
+    if( osFlushViewOfFile(pFile->pMapRegion, 0) ){
+      OSTRACE(("SYNC-MMAP pid=%lu, pFile=%p, pMapRegion=%p, "
+               "rc=SQLITE_OK\n", osGetCurrentProcessId(),
+               pFile, pFile->pMapRegion));
+    }else{
+      pFile->lastErrno = osGetLastError();
+      OSTRACE(("SYNC-MMAP pid=%lu, pFile=%p, pMapRegion=%p, "
+               "rc=SQLITE_IOERR_MMAP\n", osGetCurrentProcessId(),
+               pFile, pFile->pMapRegion));
+      return winLogError(SQLITE_IOERR_MMAP, pFile->lastErrno,
+                         "winSync1", pFile->zPath);
+    }
+  }
+#endif
+  rc = osFlushFileBuffers(pFile->h);
+  SimulateIOError( rc=FALSE );
+  if( rc ){
+    OSTRACE(("SYNC pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return SQLITE_OK;
+  }else{
+    pFile->lastErrno = osGetLastError();
+    OSTRACE(("SYNC pid=%lu, pFile=%p, file=%p, rc=SQLITE_IOERR_FSYNC\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return winLogError(SQLITE_IOERR_FSYNC, pFile->lastErrno,
+                       "winSync2", pFile->zPath);
+  }
+#endif
+}
+
+/*
+** Determine the current size of a file in bytes
+*/
+static int winFileSize(sqlite3_file *id, sqlite3_int64 *pSize){
+  winFile *pFile = (winFile*)id;
+  int rc = SQLITE_OK;
+
+  assert( id!=0 );
+  assert( pSize!=0 );
+  SimulateIOError(return SQLITE_IOERR_FSTAT);
+  OSTRACE(("SIZE file=%p, pSize=%p\n", pFile->h, pSize));
+
+#if SQLITE_OS_WINRT
+  {
+    FILE_STANDARD_INFO info;
+    if( osGetFileInformationByHandleEx(pFile->h, FileStandardInfo,
+                                     &info, sizeof(info)) ){
+      *pSize = info.EndOfFile.QuadPart;
+    }else{
+      pFile->lastErrno = osGetLastError();
+      rc = winLogError(SQLITE_IOERR_FSTAT, pFile->lastErrno,
+                       "winFileSize", pFile->zPath);
+    }
+  }
+#else
+  {
+    DWORD upperBits;
+    DWORD lowerBits;
+    DWORD lastErrno;
+
+    lowerBits = osGetFileSize(pFile->h, &upperBits);
+    *pSize = (((sqlite3_int64)upperBits)<<32) + lowerBits;
+    if(   (lowerBits == INVALID_FILE_SIZE)
+       && ((lastErrno = osGetLastError())!=NO_ERROR) ){
+      pFile->lastErrno = lastErrno;
+      rc = winLogError(SQLITE_IOERR_FSTAT, pFile->lastErrno,
+                       "winFileSize", pFile->zPath);
+    }
+  }
+#endif
+  OSTRACE(("SIZE file=%p, pSize=%p, *pSize=%lld, rc=%s\n",
+           pFile->h, pSize, *pSize, sqlite3ErrName(rc)));
+  return rc;
+}
+
+/*
+** LOCKFILE_FAIL_IMMEDIATELY is undefined on some Windows systems.
+*/
+#ifndef LOCKFILE_FAIL_IMMEDIATELY
+# define LOCKFILE_FAIL_IMMEDIATELY 1
+#endif
+
+#ifndef LOCKFILE_EXCLUSIVE_LOCK
+# define LOCKFILE_EXCLUSIVE_LOCK 2
+#endif
+
+/*
+** Historically, SQLite has used both the LockFile and LockFileEx functions.
+** When the LockFile function was used, it was always expected to fail
+** immediately if the lock could not be obtained.  Also, it always expected to
+** obtain an exclusive lock.  These flags are used with the LockFileEx function
+** and reflect those expectations; therefore, they should not be changed.
+*/
+#ifndef SQLITE_LOCKFILE_FLAGS
+# define SQLITE_LOCKFILE_FLAGS   (LOCKFILE_FAIL_IMMEDIATELY | \
+                                  LOCKFILE_EXCLUSIVE_LOCK)
+#endif
+
+/*
+** Currently, SQLite never calls the LockFileEx function without wanting the
+** call to fail immediately if the lock cannot be obtained.
+*/
+#ifndef SQLITE_LOCKFILEEX_FLAGS
+# define SQLITE_LOCKFILEEX_FLAGS (LOCKFILE_FAIL_IMMEDIATELY)
+#endif
+
+/*
+** Acquire a reader lock.
+** Different API routines are called depending on whether or not this
+** is Win9x or WinNT.
+*/
+static int winGetReadLock(winFile *pFile){
+  int res;
+  OSTRACE(("READ-LOCK file=%p, lock=%d\n", pFile->h, pFile->locktype));
+  if( osIsNT() ){
+#if SQLITE_OS_WINCE
+    /*
+    ** NOTE: Windows CE is handled differently here due its lack of the Win32
+    **       API LockFileEx.
+    */
+    res = winceLockFile(&pFile->h, SHARED_FIRST, 0, 1, 0);
+#else
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILEEX_FLAGS, SHARED_FIRST, 0,
+                      SHARED_SIZE, 0);
+#endif
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    int lk;
+    sqlite3_randomness(sizeof(lk), &lk);
+    pFile->sharedLockByte = (short)((lk & 0x7fffffff)%(SHARED_SIZE - 1));
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS,
+                      SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
+  }
+#endif
+  if( res == 0 ){
+    pFile->lastErrno = osGetLastError();
+    /* No need to log a failure to lock */
+  }
+  OSTRACE(("READ-LOCK file=%p, result=%d\n", pFile->h, res));
+  return res;
+}
+
+/*
+** Undo a readlock
+*/
+static int winUnlockReadLock(winFile *pFile){
+  int res;
+  DWORD lastErrno;
+  OSTRACE(("READ-UNLOCK file=%p, lock=%d\n", pFile->h, pFile->locktype));
+  if( osIsNT() ){
+    res = winUnlockFile(&pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    res = winUnlockFile(&pFile->h, SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
+  }
+#endif
+  if( res==0 && ((lastErrno = osGetLastError())!=ERROR_NOT_LOCKED) ){
+    pFile->lastErrno = lastErrno;
+    winLogError(SQLITE_IOERR_UNLOCK, pFile->lastErrno,
+                "winUnlockReadLock", pFile->zPath);
+  }
+  OSTRACE(("READ-UNLOCK file=%p, result=%d\n", pFile->h, res));
+  return res;
+}
+
+/*
+** Lock the file with the lock specified by parameter locktype - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  The winUnlock() routine
+** erases all locks at once and returns us immediately to locking level 0.
+** It is not possible to lower the locking level one step at a time.  You
+** must go straight to locking level 0.
+*/
+static int winLock(sqlite3_file *id, int locktype){
+  int rc = SQLITE_OK;    /* Return code from subroutines */
+  int res = 1;           /* Result of a Windows lock call */
+  int newLocktype;       /* Set pFile->locktype to this value before exiting */
+  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
+  winFile *pFile = (winFile*)id;
+  DWORD lastErrno = NO_ERROR;
+
+  assert( id!=0 );
+  OSTRACE(("LOCK file=%p, oldLock=%d(%d), newLock=%d\n",
+           pFile->h, pFile->locktype, pFile->sharedLockByte, locktype));
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** OsFile, do nothing. Don't use the end_lock: exit path, as
+  ** sqlite3OsEnterMutex() hasn't been called yet.
+  */
+  if( pFile->locktype>=locktype ){
+    OSTRACE(("LOCK-HELD file=%p, rc=SQLITE_OK\n", pFile->h));
+    return SQLITE_OK;
+  }
+
+  /* Do not allow any kind of write-lock on a read-only database
+  */
+  if( (pFile->ctrlFlags & WINFILE_RDONLY)!=0 && locktype>=RESERVED_LOCK ){
+    return SQLITE_IOERR_LOCK;
+  }
+
+  /* Make sure the locking sequence is correct
+  */
+  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
+  assert( locktype!=PENDING_LOCK );
+  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
+
+  /* Lock the PENDING_LOCK byte if we need to acquire a PENDING lock or
+  ** a SHARED lock.  If we are acquiring a SHARED lock, the acquisition of
+  ** the PENDING_LOCK byte is temporary.
+  */
+  newLocktype = pFile->locktype;
+  if( pFile->locktype==NO_LOCK
+   || (locktype==EXCLUSIVE_LOCK && pFile->locktype<=RESERVED_LOCK)
+  ){
+    int cnt = 3;
+    while( cnt-->0 && (res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS,
+                                         PENDING_BYTE, 0, 1, 0))==0 ){
+      /* Try 3 times to get the pending lock.  This is needed to work
+      ** around problems caused by indexing and/or anti-virus software on
+      ** Windows systems.
+      ** If you are using this code as a model for alternative VFSes, do not
+      ** copy this retry logic.  It is a hack intended for Windows only.
+      */
+      lastErrno = osGetLastError();
+      OSTRACE(("LOCK-PENDING-FAIL file=%p, count=%d, result=%d\n",
+               pFile->h, cnt, res));
+      if( lastErrno==ERROR_INVALID_HANDLE ){
+        pFile->lastErrno = lastErrno;
+        rc = SQLITE_IOERR_LOCK;
+        OSTRACE(("LOCK-FAIL file=%p, count=%d, rc=%s\n",
+                 pFile->h, cnt, sqlite3ErrName(rc)));
+        return rc;
+      }
+      if( cnt ) sqlite3_win32_sleep(1);
+    }
+    gotPendingLock = res;
+    if( !res ){
+      lastErrno = osGetLastError();
+    }
+  }
+
+  /* Acquire a shared lock
+  */
+  if( locktype==SHARED_LOCK && res ){
+    assert( pFile->locktype==NO_LOCK );
+    res = winGetReadLock(pFile);
+    if( res ){
+      newLocktype = SHARED_LOCK;
+    }else{
+      lastErrno = osGetLastError();
+    }
+  }
+
+  /* Acquire a RESERVED lock
+  */
+  if( locktype==RESERVED_LOCK && res ){
+    assert( pFile->locktype==SHARED_LOCK );
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS, RESERVED_BYTE, 0, 1, 0);
+    if( res ){
+      newLocktype = RESERVED_LOCK;
+    }else{
+      lastErrno = osGetLastError();
+    }
+  }
+
+  /* Acquire a PENDING lock
+  */
+  if( locktype==EXCLUSIVE_LOCK && res ){
+    newLocktype = PENDING_LOCK;
+    gotPendingLock = 0;
+  }
+
+  /* Acquire an EXCLUSIVE lock
+  */
+  if( locktype==EXCLUSIVE_LOCK && res ){
+    assert( pFile->locktype>=SHARED_LOCK );
+    (void)winUnlockReadLock(pFile);
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS, SHARED_FIRST, 0,
+                      SHARED_SIZE, 0);
+    if( res ){
+      newLocktype = EXCLUSIVE_LOCK;
+    }else{
+      lastErrno = osGetLastError();
+      winGetReadLock(pFile);
+    }
+  }
+
+  /* If we are holding a PENDING lock that ought to be released, then
+  ** release it now.
+  */
+  if( gotPendingLock && locktype==SHARED_LOCK ){
+    winUnlockFile(&pFile->h, PENDING_BYTE, 0, 1, 0);
+  }
+
+  /* Update the state of the lock has held in the file descriptor then
+  ** return the appropriate result code.
+  */
+  if( res ){
+    rc = SQLITE_OK;
+  }else{
+    pFile->lastErrno = lastErrno;
+    rc = SQLITE_BUSY;
+    OSTRACE(("LOCK-FAIL file=%p, wanted=%d, got=%d\n",
+             pFile->h, locktype, newLocktype));
+  }
+  pFile->locktype = (u8)newLocktype;
+  OSTRACE(("LOCK file=%p, lock=%d, rc=%s\n",
+           pFile->h, pFile->locktype, sqlite3ErrName(rc)));
+  return rc;
+}
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, return
+** non-zero, otherwise zero.
+*/
+static int winCheckReservedLock(sqlite3_file *id, int *pResOut){
+  int res;
+  winFile *pFile = (winFile*)id;
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+  OSTRACE(("TEST-WR-LOCK file=%p, pResOut=%p\n", pFile->h, pResOut));
+
+  assert( id!=0 );
+  if( pFile->locktype>=RESERVED_LOCK ){
+    res = 1;
+    OSTRACE(("TEST-WR-LOCK file=%p, result=%d (local)\n", pFile->h, res));
+  }else{
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILEEX_FLAGS,RESERVED_BYTE,0,1,0);
+    if( res ){
+      winUnlockFile(&pFile->h, RESERVED_BYTE, 0, 1, 0);
+    }
+    res = !res;
+    OSTRACE(("TEST-WR-LOCK file=%p, result=%d (remote)\n", pFile->h, res));
+  }
+  *pResOut = res;
+  OSTRACE(("TEST-WR-LOCK file=%p, pResOut=%p, *pResOut=%d, rc=SQLITE_OK\n",
+           pFile->h, pResOut, *pResOut));
+  return SQLITE_OK;
+}
+
+/*
+** Lower the locking level on file descriptor id to locktype.  locktype
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+**
+** It is not possible for this routine to fail if the second argument
+** is NO_LOCK.  If the second argument is SHARED_LOCK then this routine
+** might return SQLITE_IOERR;
+*/
+static int winUnlock(sqlite3_file *id, int locktype){
+  int type;
+  winFile *pFile = (winFile*)id;
+  int rc = SQLITE_OK;
+  assert( pFile!=0 );
+  assert( locktype<=SHARED_LOCK );
+  OSTRACE(("UNLOCK file=%p, oldLock=%d(%d), newLock=%d\n",
+           pFile->h, pFile->locktype, pFile->sharedLockByte, locktype));
+  type = pFile->locktype;
+  if( type>=EXCLUSIVE_LOCK ){
+    winUnlockFile(&pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+    if( locktype==SHARED_LOCK && !winGetReadLock(pFile) ){
+      /* This should never happen.  We should always be able to
+      ** reacquire the read lock */
+      rc = winLogError(SQLITE_IOERR_UNLOCK, osGetLastError(),
+                       "winUnlock", pFile->zPath);
+    }
+  }
+  if( type>=RESERVED_LOCK ){
+    winUnlockFile(&pFile->h, RESERVED_BYTE, 0, 1, 0);
+  }
+  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
+    winUnlockReadLock(pFile);
+  }
+  if( type>=PENDING_LOCK ){
+    winUnlockFile(&pFile->h, PENDING_BYTE, 0, 1, 0);
+  }
+  pFile->locktype = (u8)locktype;
+  OSTRACE(("UNLOCK file=%p, lock=%d, rc=%s\n",
+           pFile->h, pFile->locktype, sqlite3ErrName(rc)));
+  return rc;
+}
+
+/******************************************************************************
+****************************** No-op Locking **********************************
+**
+** Of the various locking implementations available, this is by far the
+** simplest:  locking is ignored.  No attempt is made to lock the database
+** file for reading or writing.
+**
+** This locking mode is appropriate for use on read-only databases
+** (ex: databases that are burned into CD-ROM, for example.)  It can
+** also be used if the application employs some external mechanism to
+** prevent simultaneous access of the same database by two or more
+** database connections.  But there is a serious risk of database
+** corruption if this locking mode is used in situations where multiple
+** database connections are accessing the same database file at the same
+** time and one or more of those connections are writing.
+*/
+
+static int winNolockLock(sqlite3_file *id, int locktype){
+  UNUSED_PARAMETER(id);
+  UNUSED_PARAMETER(locktype);
+  return SQLITE_OK;
+}
+
+static int winNolockCheckReservedLock(sqlite3_file *id, int *pResOut){
+  UNUSED_PARAMETER(id);
+  UNUSED_PARAMETER(pResOut);
+  return SQLITE_OK;
+}
+
+static int winNolockUnlock(sqlite3_file *id, int locktype){
+  UNUSED_PARAMETER(id);
+  UNUSED_PARAMETER(locktype);
+  return SQLITE_OK;
+}
+
+/******************* End of the no-op lock implementation *********************
+******************************************************************************/
+
+/*
+** If *pArg is initially negative then this is a query.  Set *pArg to
+** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
+**
+** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
+*/
+static void winModeBit(winFile *pFile, unsigned char mask, int *pArg){
+  if( *pArg<0 ){
+    *pArg = (pFile->ctrlFlags & mask)!=0;
+  }else if( (*pArg)==0 ){
+    pFile->ctrlFlags &= ~mask;
+  }else{
+    pFile->ctrlFlags |= mask;
+  }
+}
+
+/* Forward references to VFS helper methods used for temporary files */
+static int winGetTempname(sqlite3_vfs *, char **);
+static int winIsDir(const void *);
+static BOOL winIsLongPathPrefix(const char *);
+static BOOL winIsDriveLetterAndColon(const char *);
+
+/*
+** Control and query of the open file handle.
+*/
+static int winFileControl(sqlite3_file *id, int op, void *pArg){
+  winFile *pFile = (winFile*)id;
+  OSTRACE(("FCNTL file=%p, op=%d, pArg=%p\n", pFile->h, op, pArg));
+  switch( op ){
+    case SQLITE_FCNTL_LOCKSTATE: {
+      *(int*)pArg = pFile->locktype;
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_LAST_ERRNO: {
+      *(int*)pArg = (int)pFile->lastErrno;
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_CHUNK_SIZE: {
+      pFile->szChunk = *(int *)pArg;
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_SIZE_HINT: {
+      if( pFile->szChunk>0 ){
+        sqlite3_int64 oldSz;
+        int rc = winFileSize(id, &oldSz);
+        if( rc==SQLITE_OK ){
+          sqlite3_int64 newSz = *(sqlite3_int64*)pArg;
+          if( newSz>oldSz ){
+            SimulateIOErrorBenign(1);
+            rc = winTruncate(id, newSz);
+            SimulateIOErrorBenign(0);
+          }
+        }
+        OSTRACE(("FCNTL file=%p, rc=%s\n", pFile->h, sqlite3ErrName(rc)));
+        return rc;
+      }
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_PERSIST_WAL: {
+      winModeBit(pFile, WINFILE_PERSIST_WAL, (int*)pArg);
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
+      winModeBit(pFile, WINFILE_PSOW, (int*)pArg);
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_VFSNAME: {
+      *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName);
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_WIN32_AV_RETRY: {
+      int *a = (int*)pArg;
+      if( a[0]>0 ){
+        winIoerrRetry = a[0];
+      }else{
+        a[0] = winIoerrRetry;
+      }
+      if( a[1]>0 ){
+        winIoerrRetryDelay = a[1];
+      }else{
+        a[1] = winIoerrRetryDelay;
+      }
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_WIN32_GET_HANDLE: {
+      LPHANDLE phFile = (LPHANDLE)pArg;
+      *phFile = pFile->h;
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+#ifdef SQLITE_TEST
+    case SQLITE_FCNTL_WIN32_SET_HANDLE: {
+      LPHANDLE phFile = (LPHANDLE)pArg;
+      HANDLE hOldFile = pFile->h;
+      pFile->h = *phFile;
+      *phFile = hOldFile;
+      OSTRACE(("FCNTL oldFile=%p, newFile=%p, rc=SQLITE_OK\n",
+               hOldFile, pFile->h));
+      return SQLITE_OK;
+    }
+#endif
+    case SQLITE_FCNTL_NULL_IO: {
+      (void)osCloseHandle(pFile->h);
+      pFile->h = NULL;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_TEMPFILENAME: {
+      char *zTFile = 0;
+      int rc = winGetTempname(pFile->pVfs, &zTFile);
+      if( rc==SQLITE_OK ){
+        *(char**)pArg = zTFile;
+      }
+      OSTRACE(("FCNTL file=%p, rc=%s\n", pFile->h, sqlite3ErrName(rc)));
+      return rc;
+    }
+#if SQLITE_MAX_MMAP_SIZE>0
+    case SQLITE_FCNTL_MMAP_SIZE: {
+      i64 newLimit = *(i64*)pArg;
+      int rc = SQLITE_OK;
+      if( newLimit>sqlite3GlobalConfig.mxMmap ){
+        newLimit = sqlite3GlobalConfig.mxMmap;
+      }
+
+      /* The value of newLimit may be eventually cast to (SIZE_T) and passed
+      ** to MapViewOfFile(). Restrict its value to 2GB if (SIZE_T) is not at
+      ** least a 64-bit type. */
+      if( newLimit>0 && sizeof(SIZE_T)<8 ){
+        newLimit = (newLimit & 0x7FFFFFFF);
+      }
+
+      *(i64*)pArg = pFile->mmapSizeMax;
+      if( newLimit>=0 && newLimit!=pFile->mmapSizeMax && pFile->nFetchOut==0 ){
+        pFile->mmapSizeMax = newLimit;
+        if( pFile->mmapSize>0 ){
+          winUnmapfile(pFile);
+          rc = winMapfile(pFile, -1);
+        }
+      }
+      OSTRACE(("FCNTL file=%p, rc=%s\n", pFile->h, sqlite3ErrName(rc)));
+      return rc;
+    }
+#endif
+  }
+  OSTRACE(("FCNTL file=%p, rc=SQLITE_NOTFOUND\n", pFile->h));
+  return SQLITE_NOTFOUND;
+}
+
+/*
+** Return the sector size in bytes of the underlying block device for
+** the specified file. This is almost always 512 bytes, but may be
+** larger for some devices.
+**
+** SQLite code assumes this function cannot fail. It also assumes that
+** if two files are created in the same file-system directory (i.e.
+** a database and its journal file) that the sector size will be the
+** same for both.
+*/
+static int winSectorSize(sqlite3_file *id){
+  (void)id;
+  return SQLITE_DEFAULT_SECTOR_SIZE;
+}
+
+/*
+** Return a vector of device characteristics.
+*/
+static int winDeviceCharacteristics(sqlite3_file *id){
+  winFile *p = (winFile*)id;
+  return SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN | SQLITE_IOCAP_SUBPAGE_READ |
+         ((p->ctrlFlags & WINFILE_PSOW)?SQLITE_IOCAP_POWERSAFE_OVERWRITE:0);
+}
+
+/*
+** Windows will only let you create file view mappings
+** on allocation size granularity boundaries.
+** During sqlite3_os_init() we do a GetSystemInfo()
+** to get the granularity size.
+*/
+static SYSTEM_INFO winSysInfo;
+
+#ifndef SQLITE_OMIT_WAL
+
+/*
+** Helper functions to obtain and relinquish the global mutex. The
+** global mutex is used to protect the winLockInfo objects used by
+** this file, all of which may be shared by multiple threads.
+**
+** Function winShmMutexHeld() is used to assert() that the global mutex
+** is held when required. This function is only used as part of assert()
+** statements. e.g.
+**
+**   winShmEnterMutex()
+**     assert( winShmMutexHeld() );
+**   winShmLeaveMutex()
+*/
+static sqlite3_mutex *winBigLock = 0;
+static void winShmEnterMutex(void){
+  sqlite3_mutex_enter(winBigLock);
+}
+static void winShmLeaveMutex(void){
+  sqlite3_mutex_leave(winBigLock);
+}
+#ifndef NDEBUG
+static int winShmMutexHeld(void) {
+  return sqlite3_mutex_held(winBigLock);
+}
+#endif
+
+/*
+** Object used to represent a single file opened and mmapped to provide
+** shared memory.  When multiple threads all reference the same
+** log-summary, each thread has its own winFile object, but they all
+** point to a single instance of this object.  In other words, each
+** log-summary is opened only once per process.
+**
+** winShmMutexHeld() must be true when creating or destroying
+** this object or while reading or writing the following fields:
+**
+**      nRef
+**      pNext
+**
+** The following fields are read-only after the object is created:
+**
+**      fid
+**      zFilename
+**
+** Either winShmNode.mutex must be held or winShmNode.nRef==0 and
+** winShmMutexHeld() is true when reading or writing any other field
+** in this structure.
+**
+*/
+struct winShmNode {
+  sqlite3_mutex *mutex;      /* Mutex to access this object */
+  char *zFilename;           /* Name of the file */
+  winFile hFile;             /* File handle from winOpen */
+
+  int szRegion;              /* Size of shared-memory regions */
+  int nRegion;               /* Size of array apRegion */
+  u8 isReadonly;             /* True if read-only */
+  u8 isUnlocked;             /* True if no DMS lock held */
+
+  struct ShmRegion {
+    HANDLE hMap;             /* File handle from CreateFileMapping */
+    void *pMap;
+  } *aRegion;
+  DWORD lastErrno;           /* The Windows errno from the last I/O error */
+
+  int nRef;                  /* Number of winShm objects pointing to this */
+  winShm *pFirst;            /* All winShm objects pointing to this */
+  winShmNode *pNext;         /* Next in list of all winShmNode objects */
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+  u8 nextShmId;              /* Next available winShm.id value */
+#endif
+};
+
+/*
+** A global array of all winShmNode objects.
+**
+** The winShmMutexHeld() must be true while reading or writing this list.
+*/
+static winShmNode *winShmNodeList = 0;
+
+/*
+** Structure used internally by this VFS to record the state of an
+** open shared memory connection.
+**
+** The following fields are initialized when this object is created and
+** are read-only thereafter:
+**
+**    winShm.pShmNode
+**    winShm.id
+**
+** All other fields are read/write.  The winShm.pShmNode->mutex must be held
+** while accessing any read/write fields.
+*/
+struct winShm {
+  winShmNode *pShmNode;      /* The underlying winShmNode object */
+  winShm *pNext;             /* Next winShm with the same winShmNode */
+  u8 hasMutex;               /* True if holding the winShmNode mutex */
+  u16 sharedMask;            /* Mask of shared locks held */
+  u16 exclMask;              /* Mask of exclusive locks held */
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+  u8 id;                     /* Id of this connection with its winShmNode */
+#endif
+};
+
+/*
+** Constants used for locking
+*/
+#define WIN_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)        /* first lock byte */
+#define WIN_SHM_DMS    (WIN_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */
+
+/*
+** Apply advisory locks for all n bytes beginning at ofst.
+*/
+#define WINSHM_UNLCK  1
+#define WINSHM_RDLCK  2
+#define WINSHM_WRLCK  3
+static int winShmSystemLock(
+  winShmNode *pFile,    /* Apply locks to this open shared-memory segment */
+  int lockType,         /* WINSHM_UNLCK, WINSHM_RDLCK, or WINSHM_WRLCK */
+  int ofst,             /* Offset to first byte to be locked/unlocked */
+  int nByte             /* Number of bytes to lock or unlock */
+){
+  int rc = 0;           /* Result code form Lock/UnlockFileEx() */
+
+  /* Access to the winShmNode object is serialized by the caller */
+  assert( pFile->nRef==0 || sqlite3_mutex_held(pFile->mutex) );
+
+  OSTRACE(("SHM-LOCK file=%p, lock=%d, offset=%d, size=%d\n",
+           pFile->hFile.h, lockType, ofst, nByte));
+
+  /* Release/Acquire the system-level lock */
+  if( lockType==WINSHM_UNLCK ){
+    rc = winUnlockFile(&pFile->hFile.h, ofst, 0, nByte, 0);
+  }else{
+    /* Initialize the locking parameters */
+    DWORD dwFlags = LOCKFILE_FAIL_IMMEDIATELY;
+    if( lockType == WINSHM_WRLCK ) dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;
+    rc = winLockFile(&pFile->hFile.h, dwFlags, ofst, 0, nByte, 0);
+  }
+
+  if( rc!= 0 ){
+    rc = SQLITE_OK;
+  }else{
+    pFile->lastErrno =  osGetLastError();
+    rc = SQLITE_BUSY;
+  }
+
+  OSTRACE(("SHM-LOCK file=%p, func=%s, errno=%lu, rc=%s\n",
+           pFile->hFile.h, (lockType == WINSHM_UNLCK) ? "winUnlockFile" :
+           "winLockFile", pFile->lastErrno, sqlite3ErrName(rc)));
+
+  return rc;
+}
+
+/* Forward references to VFS methods */
+static int winOpen(sqlite3_vfs*,const char*,sqlite3_file*,int,int*);
+static int winDelete(sqlite3_vfs *,const char*,int);
+
+/*
+** Purge the winShmNodeList list of all entries with winShmNode.nRef==0.
+**
+** This is not a VFS shared-memory method; it is a utility function called
+** by VFS shared-memory methods.
+*/
+static void winShmPurge(sqlite3_vfs *pVfs, int deleteFlag){
+  winShmNode **pp;
+  winShmNode *p;
+  assert( winShmMutexHeld() );
+  OSTRACE(("SHM-PURGE pid=%lu, deleteFlag=%d\n",
+           osGetCurrentProcessId(), deleteFlag));
+  pp = &winShmNodeList;
+  while( (p = *pp)!=0 ){
+    if( p->nRef==0 ){
+      int i;
+      if( p->mutex ){ sqlite3_mutex_free(p->mutex); }
+      for(i=0; i<p->nRegion; i++){
+        BOOL bRc = osUnmapViewOfFile(p->aRegion[i].pMap);
+        OSTRACE(("SHM-PURGE-UNMAP pid=%lu, region=%d, rc=%s\n",
+                 osGetCurrentProcessId(), i, bRc ? "ok" : "failed"));
+        UNUSED_VARIABLE_VALUE(bRc);
+        bRc = osCloseHandle(p->aRegion[i].hMap);
+        OSTRACE(("SHM-PURGE-CLOSE pid=%lu, region=%d, rc=%s\n",
+                 osGetCurrentProcessId(), i, bRc ? "ok" : "failed"));
+        UNUSED_VARIABLE_VALUE(bRc);
+      }
+      if( p->hFile.h!=NULL && p->hFile.h!=INVALID_HANDLE_VALUE ){
+        SimulateIOErrorBenign(1);
+        winClose((sqlite3_file *)&p->hFile);
+        SimulateIOErrorBenign(0);
+      }
+      if( deleteFlag ){
+        SimulateIOErrorBenign(1);
+        sqlite3BeginBenignMalloc();
+        winDelete(pVfs, p->zFilename, 0);
+        sqlite3EndBenignMalloc();
+        SimulateIOErrorBenign(0);
+      }
+      *pp = p->pNext;
+      sqlite3_free(p->aRegion);
+      sqlite3_free(p);
+    }else{
+      pp = &p->pNext;
+    }
+  }
+}
+
+/*
+** The DMS lock has not yet been taken on shm file pShmNode. Attempt to
+** take it now. Return SQLITE_OK if successful, or an SQLite error
+** code otherwise.
+**
+** If the DMS cannot be locked because this is a readonly_shm=1
+** connection and no other process already holds a lock, return
+** SQLITE_READONLY_CANTINIT and set pShmNode->isUnlocked=1.
+*/
+static int winLockSharedMemory(winShmNode *pShmNode){
+  int rc = winShmSystemLock(pShmNode, WINSHM_WRLCK, WIN_SHM_DMS, 1);
+
+  if( rc==SQLITE_OK ){
+    if( pShmNode->isReadonly ){
+      pShmNode->isUnlocked = 1;
+      winShmSystemLock(pShmNode, WINSHM_UNLCK, WIN_SHM_DMS, 1);
+      return SQLITE_READONLY_CANTINIT;
+    }else if( winTruncate((sqlite3_file*)&pShmNode->hFile, 0) ){
+      winShmSystemLock(pShmNode, WINSHM_UNLCK, WIN_SHM_DMS, 1);
+      return winLogError(SQLITE_IOERR_SHMOPEN, osGetLastError(),
+                         "winLockSharedMemory", pShmNode->zFilename);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    winShmSystemLock(pShmNode, WINSHM_UNLCK, WIN_SHM_DMS, 1);
+  }
+
+  return winShmSystemLock(pShmNode, WINSHM_RDLCK, WIN_SHM_DMS, 1);
+}
+
+/*
+** Open the shared-memory area associated with database file pDbFd.
+**
+** When opening a new shared-memory file, if no other instances of that
+** file are currently open, in this process or in other processes, then
+** the file must be truncated to zero length or have its header cleared.
+*/
+static int winOpenSharedMemory(winFile *pDbFd){
+  struct winShm *p;                  /* The connection to be opened */
+  winShmNode *pShmNode = 0;          /* The underlying mmapped file */
+  int rc = SQLITE_OK;                /* Result code */
+  winShmNode *pNew;                  /* Newly allocated winShmNode */
+  int nName;                         /* Size of zName in bytes */
+
+  assert( pDbFd->pShm==0 );    /* Not previously opened */
+
+  /* Allocate space for the new sqlite3_shm object.  Also speculatively
+  ** allocate space for a new winShmNode and filename.
+  */
+  p = sqlite3MallocZero( sizeof(*p) );
+  if( p==0 ) return SQLITE_IOERR_NOMEM_BKPT;
+  nName = sqlite3Strlen30(pDbFd->zPath);
+  pNew = sqlite3MallocZero( sizeof(*pShmNode) + nName + 17 );
+  if( pNew==0 ){
+    sqlite3_free(p);
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+  pNew->zFilename = (char*)&pNew[1];
+  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
+  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename);
+
+  /* Look to see if there is an existing winShmNode that can be used.
+  ** If no matching winShmNode currently exists, create a new one.
+  */
+  winShmEnterMutex();
+  for(pShmNode = winShmNodeList; pShmNode; pShmNode=pShmNode->pNext){
+    /* TBD need to come up with better match here.  Perhaps
+    ** use FILE_ID_BOTH_DIR_INFO Structure.
+    */
+    if( sqlite3StrICmp(pShmNode->zFilename, pNew->zFilename)==0 ) break;
+  }
+  if( pShmNode ){
+    sqlite3_free(pNew);
+  }else{
+    int inFlags = SQLITE_OPEN_WAL;
+    int outFlags = 0;
+
+    pShmNode = pNew;
+    pNew = 0;
+    ((winFile*)(&pShmNode->hFile))->h = INVALID_HANDLE_VALUE;
+    pShmNode->pNext = winShmNodeList;
+    winShmNodeList = pShmNode;
+
+    if( sqlite3GlobalConfig.bCoreMutex ){
+      pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+      if( pShmNode->mutex==0 ){
+        rc = SQLITE_IOERR_NOMEM_BKPT;
+        goto shm_open_err;
+      }
+    }
+
+    if( 0==sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){
+      inFlags |= SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE;
+    }else{
+      inFlags |= SQLITE_OPEN_READONLY;
+    }
+    rc = winOpen(pDbFd->pVfs, pShmNode->zFilename,
+                 (sqlite3_file*)&pShmNode->hFile,
+                 inFlags, &outFlags);
+    if( rc!=SQLITE_OK ){
+      rc = winLogError(rc, osGetLastError(), "winOpenShm",
+                       pShmNode->zFilename);
+      goto shm_open_err;
+    }
+    if( outFlags==SQLITE_OPEN_READONLY ) pShmNode->isReadonly = 1;
+
+    rc = winLockSharedMemory(pShmNode);
+    if( rc!=SQLITE_OK && rc!=SQLITE_READONLY_CANTINIT ) goto shm_open_err;
+  }
+
+  /* Make the new connection a child of the winShmNode */
+  p->pShmNode = pShmNode;
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+  p->id = pShmNode->nextShmId++;
+#endif
+  pShmNode->nRef++;
+  pDbFd->pShm = p;
+  winShmLeaveMutex();
+
+  /* The reference count on pShmNode has already been incremented under
+  ** the cover of the winShmEnterMutex() mutex and the pointer from the
+  ** new (struct winShm) object to the pShmNode has been set. All that is
+  ** left to do is to link the new object into the linked list starting
+  ** at pShmNode->pFirst. This must be done while holding the pShmNode->mutex
+  ** mutex.
+  */
+  sqlite3_mutex_enter(pShmNode->mutex);
+  p->pNext = pShmNode->pFirst;
+  pShmNode->pFirst = p;
+  sqlite3_mutex_leave(pShmNode->mutex);
+  return rc;
+
+  /* Jump here on any error */
+shm_open_err:
+  winShmSystemLock(pShmNode, WINSHM_UNLCK, WIN_SHM_DMS, 1);
+  winShmPurge(pDbFd->pVfs, 0);      /* This call frees pShmNode if required */
+  sqlite3_free(p);
+  sqlite3_free(pNew);
+  winShmLeaveMutex();
+  return rc;
+}
+
+/*
+** Close a connection to shared-memory.  Delete the underlying
+** storage if deleteFlag is true.
+*/
+static int winShmUnmap(
+  sqlite3_file *fd,          /* Database holding shared memory */
+  int deleteFlag             /* Delete after closing if true */
+){
+  winFile *pDbFd;       /* Database holding shared-memory */
+  winShm *p;            /* The connection to be closed */
+  winShmNode *pShmNode; /* The underlying shared-memory file */
+  winShm **pp;          /* For looping over sibling connections */
+
+  pDbFd = (winFile*)fd;
+  p = pDbFd->pShm;
+  if( p==0 ) return SQLITE_OK;
+  pShmNode = p->pShmNode;
+
+  /* Remove connection p from the set of connections associated
+  ** with pShmNode */
+  sqlite3_mutex_enter(pShmNode->mutex);
+  for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
+  *pp = p->pNext;
+
+  /* Free the connection p */
+  sqlite3_free(p);
+  pDbFd->pShm = 0;
+  sqlite3_mutex_leave(pShmNode->mutex);
+
+  /* If pShmNode->nRef has reached 0, then close the underlying
+  ** shared-memory file, too */
+  winShmEnterMutex();
+  assert( pShmNode->nRef>0 );
+  pShmNode->nRef--;
+  if( pShmNode->nRef==0 ){
+    winShmPurge(pDbFd->pVfs, deleteFlag);
+  }
+  winShmLeaveMutex();
+
+  return SQLITE_OK;
+}
+
+/*
+** Change the lock state for a shared-memory segment.
+*/
+static int winShmLock(
+  sqlite3_file *fd,          /* Database file holding the shared memory */
+  int ofst,                  /* First lock to acquire or release */
+  int n,                     /* Number of locks to acquire or release */
+  int flags                  /* What to do with the lock */
+){
+  winFile *pDbFd = (winFile*)fd;        /* Connection holding shared memory */
+  winShm *p = pDbFd->pShm;              /* The shared memory being locked */
+  winShm *pX;                           /* For looping over all siblings */
+  winShmNode *pShmNode;
+  int rc = SQLITE_OK;                   /* Result code */
+  u16 mask;                             /* Mask of locks to take or release */
+
+  if( p==0 ) return SQLITE_IOERR_SHMLOCK;
+  pShmNode = p->pShmNode;
+  if( NEVER(pShmNode==0) ) return SQLITE_IOERR_SHMLOCK;
+
+  assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK );
+  assert( n>=1 );
+  assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) );
+  assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 );
+
+  mask = (u16)((1U<<(ofst+n)) - (1U<<ofst));
+  assert( n>1 || mask==(1<<ofst) );
+  sqlite3_mutex_enter(pShmNode->mutex);
+  if( flags & SQLITE_SHM_UNLOCK ){
+    u16 allMask = 0; /* Mask of locks held by siblings */
+
+    /* See if any siblings hold this same lock */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( pX==p ) continue;
+      assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
+      allMask |= pX->sharedMask;
+    }
+
+    /* Unlock the system-level locks */
+    if( (mask & allMask)==0 ){
+      rc = winShmSystemLock(pShmNode, WINSHM_UNLCK, ofst+WIN_SHM_BASE, n);
+    }else{
+      rc = SQLITE_OK;
+    }
+
+    /* Undo the local locks */
+    if( rc==SQLITE_OK ){
+      p->exclMask &= ~mask;
+      p->sharedMask &= ~mask;
+    }
+  }else if( flags & SQLITE_SHM_SHARED ){
+    u16 allShared = 0;  /* Union of locks held by connections other than "p" */
+
+    /* Find out which shared locks are already held by sibling connections.
+    ** If any sibling already holds an exclusive lock, go ahead and return
+    ** SQLITE_BUSY.
+    */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( (pX->exclMask & mask)!=0 ){
+        rc = SQLITE_BUSY;
+        break;
+      }
+      allShared |= pX->sharedMask;
+    }
+
+    /* Get shared locks at the system level, if necessary */
+    if( rc==SQLITE_OK ){
+      if( (allShared & mask)==0 ){
+        rc = winShmSystemLock(pShmNode, WINSHM_RDLCK, ofst+WIN_SHM_BASE, n);
+      }else{
+        rc = SQLITE_OK;
+      }
+    }
+
+    /* Get the local shared locks */
+    if( rc==SQLITE_OK ){
+      p->sharedMask |= mask;
+    }
+  }else{
+    /* Make sure no sibling connections hold locks that will block this
+    ** lock.  If any do, return SQLITE_BUSY right away.
+    */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( (pX->exclMask & mask)!=0 || (pX->sharedMask & mask)!=0 ){
+        rc = SQLITE_BUSY;
+        break;
+      }
+    }
+
+    /* Get the exclusive locks at the system level.  Then if successful
+    ** also mark the local connection as being locked.
+    */
+    if( rc==SQLITE_OK ){
+      rc = winShmSystemLock(pShmNode, WINSHM_WRLCK, ofst+WIN_SHM_BASE, n);
+      if( rc==SQLITE_OK ){
+        assert( (p->sharedMask & mask)==0 );
+        p->exclMask |= mask;
+      }
+    }
+  }
+  sqlite3_mutex_leave(pShmNode->mutex);
+  OSTRACE(("SHM-LOCK pid=%lu, id=%d, sharedMask=%03x, exclMask=%03x, rc=%s\n",
+           osGetCurrentProcessId(), p->id, p->sharedMask, p->exclMask,
+           sqlite3ErrName(rc)));
+  return rc;
+}
+
+/*
+** Implement a memory barrier or memory fence on shared memory.
+**
+** All loads and stores begun before the barrier must complete before
+** any load or store begun after the barrier.
+*/
+static void winShmBarrier(
+  sqlite3_file *fd          /* Database holding the shared memory */
+){
+  UNUSED_PARAMETER(fd);
+  sqlite3MemoryBarrier();   /* compiler-defined memory barrier */
+  winShmEnterMutex();       /* Also mutex, for redundancy */
+  winShmLeaveMutex();
+}
+
+/*
+** This function is called to obtain a pointer to region iRegion of the
+** shared-memory associated with the database file fd. Shared-memory regions
+** are numbered starting from zero. Each shared-memory region is szRegion
+** bytes in size.
+**
+** If an error occurs, an error code is returned and *pp is set to NULL.
+**
+** Otherwise, if the isWrite parameter is 0 and the requested shared-memory
+** region has not been allocated (by any client, including one running in a
+** separate process), then *pp is set to NULL and SQLITE_OK returned. If
+** isWrite is non-zero and the requested shared-memory region has not yet
+** been allocated, it is allocated by this function.
+**
+** If the shared-memory region has already been allocated or is allocated by
+** this call as described above, then it is mapped into this processes
+** address space (if it is not already), *pp is set to point to the mapped
+** memory and SQLITE_OK returned.
+*/
+static int winShmMap(
+  sqlite3_file *fd,               /* Handle open on database file */
+  int iRegion,                    /* Region to retrieve */
+  int szRegion,                   /* Size of regions */
+  int isWrite,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Mapped memory */
+){
+  winFile *pDbFd = (winFile*)fd;
+  winShm *pShm = pDbFd->pShm;
+  winShmNode *pShmNode;
+  DWORD protect = PAGE_READWRITE;
+  DWORD flags = FILE_MAP_WRITE | FILE_MAP_READ;
+  int rc = SQLITE_OK;
+
+  if( !pShm ){
+    rc = winOpenSharedMemory(pDbFd);
+    if( rc!=SQLITE_OK ) return rc;
+    pShm = pDbFd->pShm;
+    assert( pShm!=0 );
+  }
+  pShmNode = pShm->pShmNode;
+
+  sqlite3_mutex_enter(pShmNode->mutex);
+  if( pShmNode->isUnlocked ){
+    rc = winLockSharedMemory(pShmNode);
+    if( rc!=SQLITE_OK ) goto shmpage_out;
+    pShmNode->isUnlocked = 0;
+  }
+  assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
+
+  if( pShmNode->nRegion<=iRegion ){
+    struct ShmRegion *apNew;           /* New aRegion[] array */
+    int nByte = (iRegion+1)*szRegion;  /* Minimum required file size */
+    sqlite3_int64 sz;                  /* Current size of wal-index file */
+
+    pShmNode->szRegion = szRegion;
+
+    /* The requested region is not mapped into this processes address space.
+    ** Check to see if it has been allocated (i.e. if the wal-index file is
+    ** large enough to contain the requested region).
+    */
+    rc = winFileSize((sqlite3_file *)&pShmNode->hFile, &sz);
+    if( rc!=SQLITE_OK ){
+      rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
+                       "winShmMap1", pDbFd->zPath);
+      goto shmpage_out;
+    }
+
+    if( sz<nByte ){
+      /* The requested memory region does not exist. If isWrite is set to
+      ** zero, exit early. *pp will be set to NULL and SQLITE_OK returned.
+      **
+      ** Alternatively, if isWrite is non-zero, use ftruncate() to allocate
+      ** the requested memory region.
+      */
+      if( !isWrite ) goto shmpage_out;
+      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, nByte);
+      if( rc!=SQLITE_OK ){
+        rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
+                         "winShmMap2", pDbFd->zPath);
+        goto shmpage_out;
+      }
+    }
+
+    /* Map the requested memory region into this processes address space. */
+    apNew = (struct ShmRegion *)sqlite3_realloc64(
+        pShmNode->aRegion, (iRegion+1)*sizeof(apNew[0])
+    );
+    if( !apNew ){
+      rc = SQLITE_IOERR_NOMEM_BKPT;
+      goto shmpage_out;
+    }
+    pShmNode->aRegion = apNew;
+
+    if( pShmNode->isReadonly ){
+      protect = PAGE_READONLY;
+      flags = FILE_MAP_READ;
+    }
+
+    while( pShmNode->nRegion<=iRegion ){
+      HANDLE hMap = NULL;         /* file-mapping handle */
+      void *pMap = 0;             /* Mapped memory region */
+
+#if SQLITE_OS_WINRT
+      hMap = osCreateFileMappingFromApp(pShmNode->hFile.h,
+          NULL, protect, nByte, NULL
+      );
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+      hMap = osCreateFileMappingW(pShmNode->hFile.h,
+          NULL, protect, 0, nByte, NULL
+      );
+#elif defined(SQLITE_WIN32_HAS_ANSI) && SQLITE_WIN32_CREATEFILEMAPPINGA
+      hMap = osCreateFileMappingA(pShmNode->hFile.h,
+          NULL, protect, 0, nByte, NULL
+      );
+#endif
+      OSTRACE(("SHM-MAP-CREATE pid=%lu, region=%d, size=%d, rc=%s\n",
+               osGetCurrentProcessId(), pShmNode->nRegion, nByte,
+               hMap ? "ok" : "failed"));
+      if( hMap ){
+        int iOffset = pShmNode->nRegion*szRegion;
+        int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
+#if SQLITE_OS_WINRT
+        pMap = osMapViewOfFileFromApp(hMap, flags,
+            iOffset - iOffsetShift, szRegion + iOffsetShift
+        );
+#else
+        pMap = osMapViewOfFile(hMap, flags,
+            0, iOffset - iOffsetShift, szRegion + iOffsetShift
+        );
+#endif
+        OSTRACE(("SHM-MAP-MAP pid=%lu, region=%d, offset=%d, size=%d, rc=%s\n",
+                 osGetCurrentProcessId(), pShmNode->nRegion, iOffset,
+                 szRegion, pMap ? "ok" : "failed"));
+      }
+      if( !pMap ){
+        pShmNode->lastErrno = osGetLastError();
+        rc = winLogError(SQLITE_IOERR_SHMMAP, pShmNode->lastErrno,
+                         "winShmMap3", pDbFd->zPath);
+        if( hMap ) osCloseHandle(hMap);
+        goto shmpage_out;
+      }
+
+      pShmNode->aRegion[pShmNode->nRegion].pMap = pMap;
+      pShmNode->aRegion[pShmNode->nRegion].hMap = hMap;
+      pShmNode->nRegion++;
+    }
+  }
+
+shmpage_out:
+  if( pShmNode->nRegion>iRegion ){
+    int iOffset = iRegion*szRegion;
+    int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
+    char *p = (char *)pShmNode->aRegion[iRegion].pMap;
+    *pp = (void *)&p[iOffsetShift];
+  }else{
+    *pp = 0;
+  }
+  if( pShmNode->isReadonly && rc==SQLITE_OK ) rc = SQLITE_READONLY;
+  sqlite3_mutex_leave(pShmNode->mutex);
+  return rc;
+}
+
+#else
+# define winShmMap     0
+# define winShmLock    0
+# define winShmBarrier 0
+# define winShmUnmap   0
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
+/*
+** Cleans up the mapped region of the specified file, if any.
+*/
+#if SQLITE_MAX_MMAP_SIZE>0
+static int winUnmapfile(winFile *pFile){
+  assert( pFile!=0 );
+  OSTRACE(("UNMAP-FILE pid=%lu, pFile=%p, hMap=%p, pMapRegion=%p, "
+           "mmapSize=%lld, mmapSizeMax=%lld\n",
+           osGetCurrentProcessId(), pFile, pFile->hMap, pFile->pMapRegion,
+           pFile->mmapSize, pFile->mmapSizeMax));
+  if( pFile->pMapRegion ){
+    if( !osUnmapViewOfFile(pFile->pMapRegion) ){
+      pFile->lastErrno = osGetLastError();
+      OSTRACE(("UNMAP-FILE pid=%lu, pFile=%p, pMapRegion=%p, "
+               "rc=SQLITE_IOERR_MMAP\n", osGetCurrentProcessId(), pFile,
+               pFile->pMapRegion));
+      return winLogError(SQLITE_IOERR_MMAP, pFile->lastErrno,
+                         "winUnmapfile1", pFile->zPath);
+    }
+    pFile->pMapRegion = 0;
+    pFile->mmapSize = 0;
+  }
+  if( pFile->hMap!=NULL ){
+    if( !osCloseHandle(pFile->hMap) ){
+      pFile->lastErrno = osGetLastError();
+      OSTRACE(("UNMAP-FILE pid=%lu, pFile=%p, hMap=%p, rc=SQLITE_IOERR_MMAP\n",
+               osGetCurrentProcessId(), pFile, pFile->hMap));
+      return winLogError(SQLITE_IOERR_MMAP, pFile->lastErrno,
+                         "winUnmapfile2", pFile->zPath);
+    }
+    pFile->hMap = NULL;
+  }
+  OSTRACE(("UNMAP-FILE pid=%lu, pFile=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFile));
+  return SQLITE_OK;
+}
+
+/*
+** Memory map or remap the file opened by file-descriptor pFd (if the file
+** is already mapped, the existing mapping is replaced by the new). Or, if
+** there already exists a mapping for this file, and there are still
+** outstanding xFetch() references to it, this function is a no-op.
+**
+** If parameter nByte is non-negative, then it is the requested size of
+** the mapping to create. Otherwise, if nByte is less than zero, then the
+** requested size is the size of the file on disk. The actual size of the
+** created mapping is either the requested size or the value configured
+** using SQLITE_FCNTL_MMAP_SIZE, whichever is smaller.
+**
+** SQLITE_OK is returned if no error occurs (even if the mapping is not
+** recreated as a result of outstanding references) or an SQLite error
+** code otherwise.
+*/
+static int winMapfile(winFile *pFd, sqlite3_int64 nByte){
+  sqlite3_int64 nMap = nByte;
+  int rc;
+
+  assert( nMap>=0 || pFd->nFetchOut==0 );
+  OSTRACE(("MAP-FILE pid=%lu, pFile=%p, size=%lld\n",
+           osGetCurrentProcessId(), pFd, nByte));
+
+  if( pFd->nFetchOut>0 ) return SQLITE_OK;
+
+  if( nMap<0 ){
+    rc = winFileSize((sqlite3_file*)pFd, &nMap);
+    if( rc ){
+      OSTRACE(("MAP-FILE pid=%lu, pFile=%p, rc=SQLITE_IOERR_FSTAT\n",
+               osGetCurrentProcessId(), pFd));
+      return SQLITE_IOERR_FSTAT;
+    }
+  }
+  if( nMap>pFd->mmapSizeMax ){
+    nMap = pFd->mmapSizeMax;
+  }
+  nMap &= ~(sqlite3_int64)(winSysInfo.dwPageSize - 1);
+
+  if( nMap==0 && pFd->mmapSize>0 ){
+    winUnmapfile(pFd);
+  }
+  if( nMap!=pFd->mmapSize ){
+    void *pNew = 0;
+    DWORD protect = PAGE_READONLY;
+    DWORD flags = FILE_MAP_READ;
+
+    winUnmapfile(pFd);
+#ifdef SQLITE_MMAP_READWRITE
+    if( (pFd->ctrlFlags & WINFILE_RDONLY)==0 ){
+      protect = PAGE_READWRITE;
+      flags |= FILE_MAP_WRITE;
+    }
+#endif
+#if SQLITE_OS_WINRT
+    pFd->hMap = osCreateFileMappingFromApp(pFd->h, NULL, protect, nMap, NULL);
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+    pFd->hMap = osCreateFileMappingW(pFd->h, NULL, protect,
+                                (DWORD)((nMap>>32) & 0xffffffff),
+                                (DWORD)(nMap & 0xffffffff), NULL);
+#elif defined(SQLITE_WIN32_HAS_ANSI) && SQLITE_WIN32_CREATEFILEMAPPINGA
+    pFd->hMap = osCreateFileMappingA(pFd->h, NULL, protect,
+                                (DWORD)((nMap>>32) & 0xffffffff),
+                                (DWORD)(nMap & 0xffffffff), NULL);
+#endif
+    if( pFd->hMap==NULL ){
+      pFd->lastErrno = osGetLastError();
+      rc = winLogError(SQLITE_IOERR_MMAP, pFd->lastErrno,
+                       "winMapfile1", pFd->zPath);
+      /* Log the error, but continue normal operation using xRead/xWrite */
+      OSTRACE(("MAP-FILE-CREATE pid=%lu, pFile=%p, rc=%s\n",
+               osGetCurrentProcessId(), pFd, sqlite3ErrName(rc)));
+      return SQLITE_OK;
+    }
+    assert( (nMap % winSysInfo.dwPageSize)==0 );
+    assert( sizeof(SIZE_T)==sizeof(sqlite3_int64) || nMap<=0xffffffff );
+#if SQLITE_OS_WINRT
+    pNew = osMapViewOfFileFromApp(pFd->hMap, flags, 0, (SIZE_T)nMap);
+#else
+    pNew = osMapViewOfFile(pFd->hMap, flags, 0, 0, (SIZE_T)nMap);
+#endif
+    if( pNew==NULL ){
+      osCloseHandle(pFd->hMap);
+      pFd->hMap = NULL;
+      pFd->lastErrno = osGetLastError();
+      rc = winLogError(SQLITE_IOERR_MMAP, pFd->lastErrno,
+                       "winMapfile2", pFd->zPath);
+      /* Log the error, but continue normal operation using xRead/xWrite */
+      OSTRACE(("MAP-FILE-MAP pid=%lu, pFile=%p, rc=%s\n",
+               osGetCurrentProcessId(), pFd, sqlite3ErrName(rc)));
+      return SQLITE_OK;
+    }
+    pFd->pMapRegion = pNew;
+    pFd->mmapSize = nMap;
+  }
+
+  OSTRACE(("MAP-FILE pid=%lu, pFile=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFd));
+  return SQLITE_OK;
+}
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+
+/*
+** If possible, return a pointer to a mapping of file fd starting at offset
+** iOff. The mapping must be valid for at least nAmt bytes.
+**
+** If such a pointer can be obtained, store it in *pp and return SQLITE_OK.
+** Or, if one cannot but no error occurs, set *pp to 0 and return SQLITE_OK.
+** Finally, if an error does occur, return an SQLite error code. The final
+** value of *pp is undefined in this case.
+**
+** If this function does return a pointer, the caller must eventually
+** release the reference by calling winUnfetch().
+*/
+static int winFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){
+#if SQLITE_MAX_MMAP_SIZE>0
+  winFile *pFd = (winFile*)fd;   /* The underlying database file */
+#endif
+  *pp = 0;
+
+  OSTRACE(("FETCH pid=%lu, pFile=%p, offset=%lld, amount=%d, pp=%p\n",
+           osGetCurrentProcessId(), fd, iOff, nAmt, pp));
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFd->mmapSizeMax>0 ){
+    /* Ensure that there is always at least a 256 byte buffer of addressable
+    ** memory following the returned page. If the database is corrupt,
+    ** SQLite may overread the page slightly (in practice only a few bytes,
+    ** but 256 is safe, round, number).  */
+    const int nEofBuffer = 256;
+    if( pFd->pMapRegion==0 ){
+      int rc = winMapfile(pFd, -1);
+      if( rc!=SQLITE_OK ){
+        OSTRACE(("FETCH pid=%lu, pFile=%p, rc=%s\n",
+                 osGetCurrentProcessId(), pFd, sqlite3ErrName(rc)));
+        return rc;
+      }
+    }
+    if( pFd->mmapSize >= (iOff+nAmt+nEofBuffer) ){
+      assert( pFd->pMapRegion!=0 );
+      *pp = &((u8 *)pFd->pMapRegion)[iOff];
+      pFd->nFetchOut++;
+    }
+  }
+#endif
+
+  OSTRACE(("FETCH pid=%lu, pFile=%p, pp=%p, *pp=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), fd, pp, *pp));
+  return SQLITE_OK;
+}
+
+/*
+** If the third argument is non-NULL, then this function releases a
+** reference obtained by an earlier call to winFetch(). The second
+** argument passed to this function must be the same as the corresponding
+** argument that was passed to the winFetch() invocation.
+**
+** Or, if the third argument is NULL, then this function is being called
+** to inform the VFS layer that, according to POSIX, any existing mapping
+** may now be invalid and should be unmapped.
+*/
+static int winUnfetch(sqlite3_file *fd, i64 iOff, void *p){
+#if SQLITE_MAX_MMAP_SIZE>0
+  winFile *pFd = (winFile*)fd;   /* The underlying database file */
+
+  /* If p==0 (unmap the entire file) then there must be no outstanding
+  ** xFetch references. Or, if p!=0 (meaning it is an xFetch reference),
+  ** then there must be at least one outstanding.  */
+  assert( (p==0)==(pFd->nFetchOut==0) );
+
+  /* If p!=0, it must match the iOff value. */
+  assert( p==0 || p==&((u8 *)pFd->pMapRegion)[iOff] );
+
+  OSTRACE(("UNFETCH pid=%lu, pFile=%p, offset=%lld, p=%p\n",
+           osGetCurrentProcessId(), pFd, iOff, p));
+
+  if( p ){
+    pFd->nFetchOut--;
+  }else{
+    /* FIXME:  If Windows truly always prevents truncating or deleting a
+    ** file while a mapping is held, then the following winUnmapfile() call
+    ** is unnecessary can be omitted - potentially improving
+    ** performance.  */
+    winUnmapfile(pFd);
+  }
+
+  assert( pFd->nFetchOut>=0 );
+#endif
+
+  OSTRACE(("UNFETCH pid=%lu, pFile=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), fd));
+  return SQLITE_OK;
+}
+
+/*
+** Here ends the implementation of all sqlite3_file methods.
+**
+********************** End sqlite3_file Methods *******************************
+******************************************************************************/
+
+/*
+** This vector defines all the methods that can operate on an
+** sqlite3_file for win32.
+*/
+static const sqlite3_io_methods winIoMethod = {
+  3,                              /* iVersion */
+  winClose,                       /* xClose */
+  winRead,                        /* xRead */
+  winWrite,                       /* xWrite */
+  winTruncate,                    /* xTruncate */
+  winSync,                        /* xSync */
+  winFileSize,                    /* xFileSize */
+  winLock,                        /* xLock */
+  winUnlock,                      /* xUnlock */
+  winCheckReservedLock,           /* xCheckReservedLock */
+  winFileControl,                 /* xFileControl */
+  winSectorSize,                  /* xSectorSize */
+  winDeviceCharacteristics,       /* xDeviceCharacteristics */
+  winShmMap,                      /* xShmMap */
+  winShmLock,                     /* xShmLock */
+  winShmBarrier,                  /* xShmBarrier */
+  winShmUnmap,                    /* xShmUnmap */
+  winFetch,                       /* xFetch */
+  winUnfetch                      /* xUnfetch */
+};
+
+/*
+** This vector defines all the methods that can operate on an
+** sqlite3_file for win32 without performing any locking.
+*/
+static const sqlite3_io_methods winIoNolockMethod = {
+  3,                              /* iVersion */
+  winClose,                       /* xClose */
+  winRead,                        /* xRead */
+  winWrite,                       /* xWrite */
+  winTruncate,                    /* xTruncate */
+  winSync,                        /* xSync */
+  winFileSize,                    /* xFileSize */
+  winNolockLock,                  /* xLock */
+  winNolockUnlock,                /* xUnlock */
+  winNolockCheckReservedLock,     /* xCheckReservedLock */
+  winFileControl,                 /* xFileControl */
+  winSectorSize,                  /* xSectorSize */
+  winDeviceCharacteristics,       /* xDeviceCharacteristics */
+  winShmMap,                      /* xShmMap */
+  winShmLock,                     /* xShmLock */
+  winShmBarrier,                  /* xShmBarrier */
+  winShmUnmap,                    /* xShmUnmap */
+  winFetch,                       /* xFetch */
+  winUnfetch                      /* xUnfetch */
+};
+
+static winVfsAppData winAppData = {
+  &winIoMethod,       /* pMethod */
+  0,                  /* pAppData */
+  0                   /* bNoLock */
+};
+
+static winVfsAppData winNolockAppData = {
+  &winIoNolockMethod, /* pMethod */
+  0,                  /* pAppData */
+  1                   /* bNoLock */
+};
+
+/****************************************************************************
+**************************** sqlite3_vfs methods ****************************
+**
+** This division contains the implementation of methods on the
+** sqlite3_vfs object.
+*/
+
+#if defined(__CYGWIN__)
+/*
+** Convert a filename from whatever the underlying operating system
+** supports for filenames into UTF-8.  Space to hold the result is
+** obtained from malloc and must be freed by the calling function.
+*/
+static char *winConvertToUtf8Filename(const void *zFilename){
+  char *zConverted = 0;
+  if( osIsNT() ){
+    zConverted = winUnicodeToUtf8(zFilename);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    zConverted = winMbcsToUtf8(zFilename, osAreFileApisANSI());
+  }
+#endif
+  /* caller will handle out of memory */
+  return zConverted;
+}
+#endif
+
+/*
+** Convert a UTF-8 filename into whatever form the underlying
+** operating system wants filenames in.  Space to hold the result
+** is obtained from malloc and must be freed by the calling
+** function.
+*/
+static void *winConvertFromUtf8Filename(const char *zFilename){
+  void *zConverted = 0;
+  if( osIsNT() ){
+    zConverted = winUtf8ToUnicode(zFilename);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    zConverted = winUtf8ToMbcs(zFilename, osAreFileApisANSI());
+  }
+#endif
+  /* caller will handle out of memory */
+  return zConverted;
+}
+
+/*
+** This function returns non-zero if the specified UTF-8 string buffer
+** ends with a directory separator character or one was successfully
+** added to it.
+*/
+static int winMakeEndInDirSep(int nBuf, char *zBuf){
+  if( zBuf ){
+    int nLen = sqlite3Strlen30(zBuf);
+    if( nLen>0 ){
+      if( winIsDirSep(zBuf[nLen-1]) ){
+        return 1;
+      }else if( nLen+1<nBuf ){
+        zBuf[nLen] = winGetDirSep();
+        zBuf[nLen+1] = '\0';
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** If sqlite3_temp_directory is defined, take the mutex and return true.
+**
+** If sqlite3_temp_directory is NULL (undefined), omit the mutex and
+** return false.
+*/
+static int winTempDirDefined(void){
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  if( sqlite3_temp_directory!=0 ) return 1;
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return 0;
+}
+
+/*
+** Create a temporary file name and store the resulting pointer into pzBuf.
+** The pointer returned in pzBuf must be freed via sqlite3_free().
+*/
+static int winGetTempname(sqlite3_vfs *pVfs, char **pzBuf){
+  static char zChars[] =
+    "abcdefghijklmnopqrstuvwxyz"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "0123456789";
+  size_t i, j;
+  DWORD pid;
+  int nPre = sqlite3Strlen30(SQLITE_TEMP_FILE_PREFIX);
+  int nMax, nBuf, nDir, nLen;
+  char *zBuf;
+
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing.
+  */
+  SimulateIOError( return SQLITE_IOERR );
+
+  /* Allocate a temporary buffer to store the fully qualified file
+  ** name for the temporary file.  If this fails, we cannot continue.
+  */
+  nMax = pVfs->mxPathname; nBuf = nMax + 2;
+  zBuf = sqlite3MallocZero( nBuf );
+  if( !zBuf ){
+    OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+
+  /* Figure out the effective temporary directory.  First, check if one
+  ** has been explicitly set by the application; otherwise, use the one
+  ** configured by the operating system.
+  */
+  nDir = nMax - (nPre + 15);
+  assert( nDir>0 );
+  if( winTempDirDefined() ){
+    int nDirLen = sqlite3Strlen30(sqlite3_temp_directory);
+    if( nDirLen>0 ){
+      if( !winIsDirSep(sqlite3_temp_directory[nDirLen-1]) ){
+        nDirLen++;
+      }
+      if( nDirLen>nDir ){
+        sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+        sqlite3_free(zBuf);
+        OSTRACE(("TEMP-FILENAME rc=SQLITE_ERROR\n"));
+        return winLogError(SQLITE_ERROR, 0, "winGetTempname1", 0);
+      }
+      sqlite3_snprintf(nMax, zBuf, "%s", sqlite3_temp_directory);
+    }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  }
+
+#if defined(__CYGWIN__)
+  else{
+    static const char *azDirs[] = {
+       0, /* getenv("SQLITE_TMPDIR") */
+       0, /* getenv("TMPDIR") */
+       0, /* getenv("TMP") */
+       0, /* getenv("TEMP") */
+       0, /* getenv("USERPROFILE") */
+       "/var/tmp",
+       "/usr/tmp",
+       "/tmp",
+       ".",
+       0        /* List terminator */
+    };
+    unsigned int i;
+    const char *zDir = 0;
+
+    if( !azDirs[0] ) azDirs[0] = getenv("SQLITE_TMPDIR");
+    if( !azDirs[1] ) azDirs[1] = getenv("TMPDIR");
+    if( !azDirs[2] ) azDirs[2] = getenv("TMP");
+    if( !azDirs[3] ) azDirs[3] = getenv("TEMP");
+    if( !azDirs[4] ) azDirs[4] = getenv("USERPROFILE");
+    for(i=0; i<sizeof(azDirs)/sizeof(azDirs[0]); zDir=azDirs[i++]){
+      void *zConverted;
+      if( zDir==0 ) continue;
+      /* If the path starts with a drive letter followed by the colon
+      ** character, assume it is already a native Win32 path; otherwise,
+      ** it must be converted to a native Win32 path via the Cygwin API
+      ** prior to using it.
+      */
+      if( winIsDriveLetterAndColon(zDir) ){
+        zConverted = winConvertFromUtf8Filename(zDir);
+        if( !zConverted ){
+          sqlite3_free(zBuf);
+          OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+          return SQLITE_IOERR_NOMEM_BKPT;
+        }
+        if( winIsDir(zConverted) ){
+          sqlite3_snprintf(nMax, zBuf, "%s", zDir);
+          sqlite3_free(zConverted);
+          break;
+        }
+        sqlite3_free(zConverted);
+      }else{
+        zConverted = sqlite3MallocZero( nMax+1 );
+        if( !zConverted ){
+          sqlite3_free(zBuf);
+          OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+          return SQLITE_IOERR_NOMEM_BKPT;
+        }
+        if( cygwin_conv_path(
+                osIsNT() ? CCP_POSIX_TO_WIN_W : CCP_POSIX_TO_WIN_A, zDir,
+                zConverted, nMax+1)<0 ){
+          sqlite3_free(zConverted);
+          sqlite3_free(zBuf);
+          OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_CONVPATH\n"));
+          return winLogError(SQLITE_IOERR_CONVPATH, (DWORD)errno,
+                             "winGetTempname2", zDir);
+        }
+        if( winIsDir(zConverted) ){
+          /* At this point, we know the candidate directory exists and should
+          ** be used.  However, we may need to convert the string containing
+          ** its name into UTF-8 (i.e. if it is UTF-16 right now).
+          */
+          char *zUtf8 = winConvertToUtf8Filename(zConverted);
+          if( !zUtf8 ){
+            sqlite3_free(zConverted);
+            sqlite3_free(zBuf);
+            OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+            return SQLITE_IOERR_NOMEM_BKPT;
+          }
+          sqlite3_snprintf(nMax, zBuf, "%s", zUtf8);
+          sqlite3_free(zUtf8);
+          sqlite3_free(zConverted);
+          break;
+        }
+        sqlite3_free(zConverted);
+      }
+    }
+  }
+#elif !SQLITE_OS_WINRT && !defined(__CYGWIN__)
+  else if( osIsNT() ){
+    char *zMulti;
+    LPWSTR zWidePath = sqlite3MallocZero( nMax*sizeof(WCHAR) );
+    if( !zWidePath ){
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    if( osGetTempPathW(nMax, zWidePath)==0 ){
+      sqlite3_free(zWidePath);
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_GETTEMPPATH\n"));
+      return winLogError(SQLITE_IOERR_GETTEMPPATH, osGetLastError(),
+                         "winGetTempname2", 0);
+    }
+    zMulti = winUnicodeToUtf8(zWidePath);
+    if( zMulti ){
+      sqlite3_snprintf(nMax, zBuf, "%s", zMulti);
+      sqlite3_free(zMulti);
+      sqlite3_free(zWidePath);
+    }else{
+      sqlite3_free(zWidePath);
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    char *zUtf8;
+    char *zMbcsPath = sqlite3MallocZero( nMax );
+    if( !zMbcsPath ){
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    if( osGetTempPathA(nMax, zMbcsPath)==0 ){
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_GETTEMPPATH\n"));
+      return winLogError(SQLITE_IOERR_GETTEMPPATH, osGetLastError(),
+                         "winGetTempname3", 0);
+    }
+    zUtf8 = winMbcsToUtf8(zMbcsPath, osAreFileApisANSI());
+    if( zUtf8 ){
+      sqlite3_snprintf(nMax, zBuf, "%s", zUtf8);
+      sqlite3_free(zUtf8);
+    }else{
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+  }
+#endif /* SQLITE_WIN32_HAS_ANSI */
+#endif /* !SQLITE_OS_WINRT */
+
+  /*
+  ** Check to make sure the temporary directory ends with an appropriate
+  ** separator.  If it does not and there is not enough space left to add
+  ** one, fail.
+  */
+  if( !winMakeEndInDirSep(nDir+1, zBuf) ){
+    sqlite3_free(zBuf);
+    OSTRACE(("TEMP-FILENAME rc=SQLITE_ERROR\n"));
+    return winLogError(SQLITE_ERROR, 0, "winGetTempname4", 0);
+  }
+
+  /*
+  ** Check that the output buffer is large enough for the temporary file
+  ** name in the following format:
+  **
+  **   "<temporary_directory>/etilqs_XXXXXXXXXXXXXXX\0\0"
+  **
+  ** If not, return SQLITE_ERROR.  The number 17 is used here in order to
+  ** account for the space used by the 15 character random suffix and the
+  ** two trailing NUL characters.  The final directory separator character
+  ** has already added if it was not already present.
+  */
+  nLen = sqlite3Strlen30(zBuf);
+  if( (nLen + nPre + 17) > nBuf ){
+    sqlite3_free(zBuf);
+    OSTRACE(("TEMP-FILENAME rc=SQLITE_ERROR\n"));
+    return winLogError(SQLITE_ERROR, 0, "winGetTempname5", 0);
+  }
+
+  sqlite3_snprintf(nBuf-16-nLen, zBuf+nLen, SQLITE_TEMP_FILE_PREFIX);
+
+  j = sqlite3Strlen30(zBuf);
+  sqlite3_randomness(15, &zBuf[j]);
+  pid = osGetCurrentProcessId();
+  for(i=0; i<15; i++, j++){
+    zBuf[j] += pid & 0xff;
+    pid >>= 8;
+    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
+  }
+  zBuf[j] = 0;
+  zBuf[j+1] = 0;
+  *pzBuf = zBuf;
+
+  OSTRACE(("TEMP-FILENAME name=%s, rc=SQLITE_OK\n", zBuf));
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the named file is really a directory.  Return false if
+** it is something other than a directory, or if there is any kind of memory
+** allocation failure.
+*/
+static int winIsDir(const void *zConverted){
+  DWORD attr;
+  int rc = 0;
+  DWORD lastErrno;
+
+  if( osIsNT() ){
+    int cnt = 0;
+    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+    memset(&sAttrData, 0, sizeof(sAttrData));
+    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
+                             GetFileExInfoStandard,
+                             &sAttrData)) && winRetryIoerr(&cnt, &lastErrno) ){}
+    if( !rc ){
+      return 0; /* Invalid name? */
+    }
+    attr = sAttrData.dwFileAttributes;
+#if SQLITE_OS_WINCE==0
+  }else{
+    attr = osGetFileAttributesA((char*)zConverted);
+#endif
+  }
+  return (attr!=INVALID_FILE_ATTRIBUTES) && (attr&FILE_ATTRIBUTE_DIRECTORY);
+}
+
+/* forward reference */
+static int winAccess(
+  sqlite3_vfs *pVfs,         /* Not used on win32 */
+  const char *zFilename,     /* Name of file to check */
+  int flags,                 /* Type of test to make on this file */
+  int *pResOut               /* OUT: Result */
+);
+
+/*
+** Open a file.
+*/
+static int winOpen(
+  sqlite3_vfs *pVfs,        /* Used to get maximum path length and AppData */
+  const char *zName,        /* Name of the file (UTF-8) */
+  sqlite3_file *id,         /* Write the SQLite file handle here */
+  int flags,                /* Open mode flags */
+  int *pOutFlags            /* Status return flags */
+){
+  HANDLE h;
+  DWORD lastErrno = 0;
+  DWORD dwDesiredAccess;
+  DWORD dwShareMode;
+  DWORD dwCreationDisposition;
+  DWORD dwFlagsAndAttributes = 0;
+#if SQLITE_OS_WINCE
+  int isTemp = 0;
+#endif
+  winVfsAppData *pAppData;
+  winFile *pFile = (winFile*)id;
+  void *zConverted;              /* Filename in OS encoding */
+  const char *zUtf8Name = zName; /* Filename in UTF-8 encoding */
+  int cnt = 0;
+
+  /* If argument zPath is a NULL pointer, this function is required to open
+  ** a temporary file. Use this buffer to store the file name in.
+  */
+  char *zTmpname = 0; /* For temporary filename, if necessary. */
+
+  int rc = SQLITE_OK;            /* Function Return Code */
+#if !defined(NDEBUG) || SQLITE_OS_WINCE
+  int eType = flags&0x0FFF00;  /* Type of file to open */
+#endif
+
+  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
+  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
+  int isCreate     = (flags & SQLITE_OPEN_CREATE);
+  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
+  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
+
+#ifndef NDEBUG
+  int isOpenJournal = (isCreate && (
+        eType==SQLITE_OPEN_SUPER_JOURNAL
+     || eType==SQLITE_OPEN_MAIN_JOURNAL
+     || eType==SQLITE_OPEN_WAL
+  ));
+#endif
+
+  OSTRACE(("OPEN name=%s, pFile=%p, flags=%x, pOutFlags=%p\n",
+           zUtf8Name, id, flags, pOutFlags));
+
+  /* Check the following statements are true:
+  **
+  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and
+  **   (b) if CREATE is set, then READWRITE must also be set, and
+  **   (c) if EXCLUSIVE is set, then CREATE must also be set.
+  **   (d) if DELETEONCLOSE is set, then CREATE must also be set.
+  */
+  assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly));
+  assert(isCreate==0 || isReadWrite);
+  assert(isExclusive==0 || isCreate);
+  assert(isDelete==0 || isCreate);
+
+  /* The main DB, main journal, WAL file and super-journal are never
+  ** automatically deleted. Nor are they ever temporary files.  */
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_DB );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_SUPER_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_WAL );
+
+  /* Assert that the upper layer has set one of the "file-type" flags. */
+  assert( eType==SQLITE_OPEN_MAIN_DB      || eType==SQLITE_OPEN_TEMP_DB
+       || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL
+       || eType==SQLITE_OPEN_SUBJOURNAL   || eType==SQLITE_OPEN_SUPER_JOURNAL
+       || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL
+  );
+
+  assert( pFile!=0 );
+  memset(pFile, 0, sizeof(winFile));
+  pFile->h = INVALID_HANDLE_VALUE;
+
+#if SQLITE_OS_WINRT
+  if( !zUtf8Name && !sqlite3_temp_directory ){
+    sqlite3_log(SQLITE_ERROR,
+        "sqlite3_temp_directory variable should be set for WinRT");
+  }
+#endif
+
+  /* If the second argument to this function is NULL, generate a
+  ** temporary file name to use
+  */
+  if( !zUtf8Name ){
+    assert( isDelete && !isOpenJournal );
+    rc = winGetTempname(pVfs, &zTmpname);
+    if( rc!=SQLITE_OK ){
+      OSTRACE(("OPEN name=%s, rc=%s", zUtf8Name, sqlite3ErrName(rc)));
+      return rc;
+    }
+    zUtf8Name = zTmpname;
+  }
+
+  /* Database filenames are double-zero terminated if they are not
+  ** URIs with parameters.  Hence, they can always be passed into
+  ** sqlite3_uri_parameter().
+  */
+  assert( (eType!=SQLITE_OPEN_MAIN_DB) || (flags & SQLITE_OPEN_URI) ||
+       zUtf8Name[sqlite3Strlen30(zUtf8Name)+1]==0 );
+
+  /* Convert the filename to the system encoding. */
+  zConverted = winConvertFromUtf8Filename(zUtf8Name);
+  if( zConverted==0 ){
+    sqlite3_free(zTmpname);
+    OSTRACE(("OPEN name=%s, rc=SQLITE_IOERR_NOMEM", zUtf8Name));
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+
+  if( winIsDir(zConverted) ){
+    sqlite3_free(zConverted);
+    sqlite3_free(zTmpname);
+    OSTRACE(("OPEN name=%s, rc=SQLITE_CANTOPEN_ISDIR", zUtf8Name));
+    return SQLITE_CANTOPEN_ISDIR;
+  }
+
+  if( isReadWrite ){
+    dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
+  }else{
+    dwDesiredAccess = GENERIC_READ;
+  }
+
+  /* SQLITE_OPEN_EXCLUSIVE is used to make sure that a new file is
+  ** created. SQLite doesn't use it to indicate "exclusive access"
+  ** as it is usually understood.
+  */
+  if( isExclusive ){
+    /* Creates a new file, only if it does not already exist. */
+    /* If the file exists, it fails. */
+    dwCreationDisposition = CREATE_NEW;
+  }else if( isCreate ){
+    /* Open existing file, or create if it doesn't exist */
+    dwCreationDisposition = OPEN_ALWAYS;
+  }else{
+    /* Opens a file, only if it exists. */
+    dwCreationDisposition = OPEN_EXISTING;
+  }
+
+  if( 0==sqlite3_uri_boolean(zName, "exclusive", 0) ){
+    dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;
+  }else{
+    dwShareMode = 0;
+  }
+
+  if( isDelete ){
+#if SQLITE_OS_WINCE
+    dwFlagsAndAttributes = FILE_ATTRIBUTE_HIDDEN;
+    isTemp = 1;
+#else
+    dwFlagsAndAttributes = FILE_ATTRIBUTE_TEMPORARY
+                               | FILE_ATTRIBUTE_HIDDEN
+                               | FILE_FLAG_DELETE_ON_CLOSE;
+#endif
+  }else{
+    dwFlagsAndAttributes = FILE_ATTRIBUTE_NORMAL;
+  }
+  /* Reports from the internet are that performance is always
+  ** better if FILE_FLAG_RANDOM_ACCESS is used.  Ticket #2699. */
+#if SQLITE_OS_WINCE
+  dwFlagsAndAttributes |= FILE_FLAG_RANDOM_ACCESS;
+#endif
+
+  if( osIsNT() ){
+#if SQLITE_OS_WINRT
+    CREATEFILE2_EXTENDED_PARAMETERS extendedParameters;
+    extendedParameters.dwSize = sizeof(CREATEFILE2_EXTENDED_PARAMETERS);
+    extendedParameters.dwFileAttributes =
+            dwFlagsAndAttributes & FILE_ATTRIBUTE_MASK;
+    extendedParameters.dwFileFlags = dwFlagsAndAttributes & FILE_FLAG_MASK;
+    extendedParameters.dwSecurityQosFlags = SECURITY_ANONYMOUS;
+    extendedParameters.lpSecurityAttributes = NULL;
+    extendedParameters.hTemplateFile = NULL;
+    do{
+      h = osCreateFile2((LPCWSTR)zConverted,
+                        dwDesiredAccess,
+                        dwShareMode,
+                        dwCreationDisposition,
+                        &extendedParameters);
+      if( h!=INVALID_HANDLE_VALUE ) break;
+      if( isReadWrite ){
+        int rc2, isRO = 0;
+        sqlite3BeginBenignMalloc();
+        rc2 = winAccess(pVfs, zUtf8Name, SQLITE_ACCESS_READ, &isRO);
+        sqlite3EndBenignMalloc();
+        if( rc2==SQLITE_OK && isRO ) break;
+      }
+    }while( winRetryIoerr(&cnt, &lastErrno) );
+#else
+    do{
+      h = osCreateFileW((LPCWSTR)zConverted,
+                        dwDesiredAccess,
+                        dwShareMode, NULL,
+                        dwCreationDisposition,
+                        dwFlagsAndAttributes,
+                        NULL);
+      if( h!=INVALID_HANDLE_VALUE ) break;
+      if( isReadWrite ){
+        int rc2, isRO = 0;
+        sqlite3BeginBenignMalloc();
+        rc2 = winAccess(pVfs, zUtf8Name, SQLITE_ACCESS_READ, &isRO);
+        sqlite3EndBenignMalloc();
+        if( rc2==SQLITE_OK && isRO ) break;
+      }
+    }while( winRetryIoerr(&cnt, &lastErrno) );
+#endif
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    do{
+      h = osCreateFileA((LPCSTR)zConverted,
+                        dwDesiredAccess,
+                        dwShareMode, NULL,
+                        dwCreationDisposition,
+                        dwFlagsAndAttributes,
+                        NULL);
+      if( h!=INVALID_HANDLE_VALUE ) break;
+      if( isReadWrite ){
+        int rc2, isRO = 0;
+        sqlite3BeginBenignMalloc();
+        rc2 = winAccess(pVfs, zUtf8Name, SQLITE_ACCESS_READ, &isRO);
+        sqlite3EndBenignMalloc();
+        if( rc2==SQLITE_OK && isRO ) break;
+      }
+    }while( winRetryIoerr(&cnt, &lastErrno) );
+  }
+#endif
+  winLogIoerr(cnt, __LINE__);
+
+  OSTRACE(("OPEN file=%p, name=%s, access=%lx, rc=%s\n", h, zUtf8Name,
+           dwDesiredAccess, (h==INVALID_HANDLE_VALUE) ? "failed" : "ok"));
+
+  if( h==INVALID_HANDLE_VALUE ){
+    sqlite3_free(zConverted);
+    sqlite3_free(zTmpname);
+    if( isReadWrite && !isExclusive ){
+      return winOpen(pVfs, zName, id,
+         ((flags|SQLITE_OPEN_READONLY) &
+                     ~(SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE)),
+         pOutFlags);
+    }else{
+      pFile->lastErrno = lastErrno;
+      winLogError(SQLITE_CANTOPEN, pFile->lastErrno, "winOpen", zUtf8Name);
+      return SQLITE_CANTOPEN_BKPT;
+    }
+  }
+
+  if( pOutFlags ){
+    if( isReadWrite ){
+      *pOutFlags = SQLITE_OPEN_READWRITE;
+    }else{
+      *pOutFlags = SQLITE_OPEN_READONLY;
+    }
+  }
+
+  OSTRACE(("OPEN file=%p, name=%s, access=%lx, pOutFlags=%p, *pOutFlags=%d, "
+           "rc=%s\n", h, zUtf8Name, dwDesiredAccess, pOutFlags, pOutFlags ?
+           *pOutFlags : 0, (h==INVALID_HANDLE_VALUE) ? "failed" : "ok"));
+
+  pAppData = (winVfsAppData*)pVfs->pAppData;
+
+#if SQLITE_OS_WINCE
+  {
+    if( isReadWrite && eType==SQLITE_OPEN_MAIN_DB
+         && ((pAppData==NULL) || !pAppData->bNoLock)
+         && (rc = winceCreateLock(zName, pFile))!=SQLITE_OK
+    ){
+      osCloseHandle(h);
+      sqlite3_free(zConverted);
+      sqlite3_free(zTmpname);
+      OSTRACE(("OPEN-CE-LOCK name=%s, rc=%s\n", zName, sqlite3ErrName(rc)));
+      return rc;
+    }
+  }
+  if( isTemp ){
+    pFile->zDeleteOnClose = zConverted;
+  }else
+#endif
+  {
+    sqlite3_free(zConverted);
+  }
+
+  sqlite3_free(zTmpname);
+  id->pMethods = pAppData ? pAppData->pMethod : &winIoMethod;
+  pFile->pVfs = pVfs;
+  pFile->h = h;
+  if( isReadonly ){
+    pFile->ctrlFlags |= WINFILE_RDONLY;
+  }
+  if( (flags & SQLITE_OPEN_MAIN_DB)
+   && sqlite3_uri_boolean(zName, "psow", SQLITE_POWERSAFE_OVERWRITE)
+  ){
+    pFile->ctrlFlags |= WINFILE_PSOW;
+  }
+  pFile->lastErrno = NO_ERROR;
+  pFile->zPath = zName;
+#if SQLITE_MAX_MMAP_SIZE>0
+  pFile->hMap = NULL;
+  pFile->pMapRegion = 0;
+  pFile->mmapSize = 0;
+  pFile->mmapSizeMax = sqlite3GlobalConfig.szMmap;
+#endif
+
+  OpenCounter(+1);
+  return rc;
+}
+
+/*
+** Delete the named file.
+**
+** Note that Windows does not allow a file to be deleted if some other
+** process has it open.  Sometimes a virus scanner or indexing program
+** will open a journal file shortly after it is created in order to do
+** whatever it does.  While this other process is holding the
+** file open, we will be unable to delete it.  To work around this
+** problem, we delay 100 milliseconds and try to delete again.  Up
+** to MX_DELETION_ATTEMPTs deletion attempts are run before giving
+** up and returning an error.
+*/
+static int winDelete(
+  sqlite3_vfs *pVfs,          /* Not used on win32 */
+  const char *zFilename,      /* Name of file to delete */
+  int syncDir                 /* Not used on win32 */
+){
+  int cnt = 0;
+  int rc;
+  DWORD attr;
+  DWORD lastErrno = 0;
+  void *zConverted;
+  UNUSED_PARAMETER(pVfs);
+  UNUSED_PARAMETER(syncDir);
+
+  SimulateIOError(return SQLITE_IOERR_DELETE);
+  OSTRACE(("DELETE name=%s, syncDir=%d\n", zFilename, syncDir));
+
+  zConverted = winConvertFromUtf8Filename(zFilename);
+  if( zConverted==0 ){
+    OSTRACE(("DELETE name=%s, rc=SQLITE_IOERR_NOMEM\n", zFilename));
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+  if( osIsNT() ){
+    do {
+#if SQLITE_OS_WINRT
+      WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+      memset(&sAttrData, 0, sizeof(sAttrData));
+      if ( osGetFileAttributesExW(zConverted, GetFileExInfoStandard,
+                                  &sAttrData) ){
+        attr = sAttrData.dwFileAttributes;
+      }else{
+        lastErrno = osGetLastError();
+        if( lastErrno==ERROR_FILE_NOT_FOUND
+         || lastErrno==ERROR_PATH_NOT_FOUND ){
+          rc = SQLITE_IOERR_DELETE_NOENT; /* Already gone? */
+        }else{
+          rc = SQLITE_ERROR;
+        }
+        break;
+      }
+#else
+      attr = osGetFileAttributesW(zConverted);
+#endif
+      if ( attr==INVALID_FILE_ATTRIBUTES ){
+        lastErrno = osGetLastError();
+        if( lastErrno==ERROR_FILE_NOT_FOUND
+         || lastErrno==ERROR_PATH_NOT_FOUND ){
+          rc = SQLITE_IOERR_DELETE_NOENT; /* Already gone? */
+        }else{
+          rc = SQLITE_ERROR;
+        }
+        break;
+      }
+      if ( attr&FILE_ATTRIBUTE_DIRECTORY ){
+        rc = SQLITE_ERROR; /* Files only. */
+        break;
+      }
+      if ( osDeleteFileW(zConverted) ){
+        rc = SQLITE_OK; /* Deleted OK. */
+        break;
+      }
+      if ( !winRetryIoerr(&cnt, &lastErrno) ){
+        rc = SQLITE_ERROR; /* No more retries. */
+        break;
+      }
+    } while(1);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    do {
+      attr = osGetFileAttributesA(zConverted);
+      if ( attr==INVALID_FILE_ATTRIBUTES ){
+        lastErrno = osGetLastError();
+        if( lastErrno==ERROR_FILE_NOT_FOUND
+         || lastErrno==ERROR_PATH_NOT_FOUND ){
+          rc = SQLITE_IOERR_DELETE_NOENT; /* Already gone? */
+        }else{
+          rc = SQLITE_ERROR;
+        }
+        break;
+      }
+      if ( attr&FILE_ATTRIBUTE_DIRECTORY ){
+        rc = SQLITE_ERROR; /* Files only. */
+        break;
+      }
+      if ( osDeleteFileA(zConverted) ){
+        rc = SQLITE_OK; /* Deleted OK. */
+        break;
+      }
+      if ( !winRetryIoerr(&cnt, &lastErrno) ){
+        rc = SQLITE_ERROR; /* No more retries. */
+        break;
+      }
+    } while(1);
+  }
+#endif
+  if( rc && rc!=SQLITE_IOERR_DELETE_NOENT ){
+    rc = winLogError(SQLITE_IOERR_DELETE, lastErrno, "winDelete", zFilename);
+  }else{
+    winLogIoerr(cnt, __LINE__);
+  }
+  sqlite3_free(zConverted);
+  OSTRACE(("DELETE name=%s, rc=%s\n", zFilename, sqlite3ErrName(rc)));
+  return rc;
+}
+
+/*
+** Check the existence and status of a file.
+*/
+static int winAccess(
+  sqlite3_vfs *pVfs,         /* Not used on win32 */
+  const char *zFilename,     /* Name of file to check */
+  int flags,                 /* Type of test to make on this file */
+  int *pResOut               /* OUT: Result */
+){
+  DWORD attr;
+  int rc = 0;
+  DWORD lastErrno = 0;
+  void *zConverted;
+  UNUSED_PARAMETER(pVfs);
+
+  SimulateIOError( return SQLITE_IOERR_ACCESS; );
+  OSTRACE(("ACCESS name=%s, flags=%x, pResOut=%p\n",
+           zFilename, flags, pResOut));
+
+  if( zFilename==0 ){
+    *pResOut = 0;
+    OSTRACE(("ACCESS name=%s, pResOut=%p, *pResOut=%d, rc=SQLITE_OK\n",
+             zFilename, pResOut, *pResOut));
+    return SQLITE_OK;
+  }
+
+  zConverted = winConvertFromUtf8Filename(zFilename);
+  if( zConverted==0 ){
+    OSTRACE(("ACCESS name=%s, rc=SQLITE_IOERR_NOMEM\n", zFilename));
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+  if( osIsNT() ){
+    int cnt = 0;
+    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+    memset(&sAttrData, 0, sizeof(sAttrData));
+    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
+                             GetFileExInfoStandard,
+                             &sAttrData)) && winRetryIoerr(&cnt, &lastErrno) ){}
+    if( rc ){
+      /* For an SQLITE_ACCESS_EXISTS query, treat a zero-length file
+      ** as if it does not exist.
+      */
+      if(    flags==SQLITE_ACCESS_EXISTS
+          && sAttrData.nFileSizeHigh==0
+          && sAttrData.nFileSizeLow==0 ){
+        attr = INVALID_FILE_ATTRIBUTES;
+      }else{
+        attr = sAttrData.dwFileAttributes;
+      }
+    }else{
+      winLogIoerr(cnt, __LINE__);
+      if( lastErrno!=ERROR_FILE_NOT_FOUND && lastErrno!=ERROR_PATH_NOT_FOUND ){
+        sqlite3_free(zConverted);
+        return winLogError(SQLITE_IOERR_ACCESS, lastErrno, "winAccess",
+                           zFilename);
+      }else{
+        attr = INVALID_FILE_ATTRIBUTES;
+      }
+    }
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    attr = osGetFileAttributesA((char*)zConverted);
+  }
+#endif
+  sqlite3_free(zConverted);
+  switch( flags ){
+    case SQLITE_ACCESS_READ:
+    case SQLITE_ACCESS_EXISTS:
+      rc = attr!=INVALID_FILE_ATTRIBUTES;
+      break;
+    case SQLITE_ACCESS_READWRITE:
+      rc = attr!=INVALID_FILE_ATTRIBUTES &&
+             (attr & FILE_ATTRIBUTE_READONLY)==0;
+      break;
+    default:
+      assert(!"Invalid flags argument");
+  }
+  *pResOut = rc;
+  OSTRACE(("ACCESS name=%s, pResOut=%p, *pResOut=%d, rc=SQLITE_OK\n",
+           zFilename, pResOut, *pResOut));
+  return SQLITE_OK;
+}
+
+/*
+** Returns non-zero if the specified path name starts with the "long path"
+** prefix.
+*/
+static BOOL winIsLongPathPrefix(
+  const char *zPathname
+){
+  return ( zPathname[0]=='\\' && zPathname[1]=='\\'
+        && zPathname[2]=='?'  && zPathname[3]=='\\' );
+}
+
+/*
+** Returns non-zero if the specified path name starts with a drive letter
+** followed by a colon character.
+*/
+static BOOL winIsDriveLetterAndColon(
+  const char *zPathname
+){
+  return ( sqlite3Isalpha(zPathname[0]) && zPathname[1]==':' );
+}
+
+/*
+** Returns non-zero if the specified path name should be used verbatim.  If
+** non-zero is returned from this function, the calling function must simply
+** use the provided path name verbatim -OR- resolve it into a full path name
+** using the GetFullPathName Win32 API function (if available).
+*/
+static BOOL winIsVerbatimPathname(
+  const char *zPathname
+){
+  /*
+  ** If the path name starts with a forward slash or a backslash, it is either
+  ** a legal UNC name, a volume relative path, or an absolute path name in the
+  ** "Unix" format on Windows.  There is no easy way to differentiate between
+  ** the final two cases; therefore, we return the safer return value of TRUE
+  ** so that callers of this function will simply use it verbatim.
+  */
+  if ( winIsDirSep(zPathname[0]) ){
+    return TRUE;
+  }
+
+  /*
+  ** If the path name starts with a letter and a colon it is either a volume
+  ** relative path or an absolute path.  Callers of this function must not
+  ** attempt to treat it as a relative path name (i.e. they should simply use
+  ** it verbatim).
+  */
+  if ( winIsDriveLetterAndColon(zPathname) ){
+    return TRUE;
+  }
+
+  /*
+  ** If we get to this point, the path name should almost certainly be a purely
+  ** relative one (i.e. not a UNC name, not absolute, and not volume relative).
+  */
+  return FALSE;
+}
+
+/*
+** Turn a relative pathname into a full pathname.  Write the full
+** pathname into zOut[].  zOut[] will be at least pVfs->mxPathname
+** bytes in size.
+*/
+static int winFullPathnameNoMutex(
+  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
+  const char *zRelative,        /* Possibly relative input path */
+  int nFull,                    /* Size of output buffer in bytes */
+  char *zFull                   /* Output buffer */
+){
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && !defined(__CYGWIN__)
+  DWORD nByte;
+  void *zConverted;
+  char *zOut;
+#endif
+
+  /* If this path name begins with "/X:" or "\\?\", where "X" is any
+  ** alphabetic character, discard the initial "/" from the pathname.
+  */
+  if( zRelative[0]=='/' && (winIsDriveLetterAndColon(zRelative+1)
+       || winIsLongPathPrefix(zRelative+1)) ){
+    zRelative++;
+  }
+
+#if defined(__CYGWIN__)
+  SimulateIOError( return SQLITE_ERROR );
+  UNUSED_PARAMETER(nFull);
+  assert( nFull>=pVfs->mxPathname );
+  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
+    /*
+    ** NOTE: We are dealing with a relative path name and the data
+    **       directory has been set.  Therefore, use it as the basis
+    **       for converting the relative path name to an absolute
+    **       one by prepending the data directory and a slash.
+    */
+    char *zOut = sqlite3MallocZero( pVfs->mxPathname+1 );
+    if( !zOut ){
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    if( cygwin_conv_path(
+            (osIsNT() ? CCP_POSIX_TO_WIN_W : CCP_POSIX_TO_WIN_A) |
+            CCP_RELATIVE, zRelative, zOut, pVfs->mxPathname+1)<0 ){
+      sqlite3_free(zOut);
+      return winLogError(SQLITE_CANTOPEN_CONVPATH, (DWORD)errno,
+                         "winFullPathname1", zRelative);
+    }else{
+      char *zUtf8 = winConvertToUtf8Filename(zOut);
+      if( !zUtf8 ){
+        sqlite3_free(zOut);
+        return SQLITE_IOERR_NOMEM_BKPT;
+      }
+      sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s%c%s",
+                       sqlite3_data_directory, winGetDirSep(), zUtf8);
+      sqlite3_free(zUtf8);
+      sqlite3_free(zOut);
+    }
+  }else{
+    char *zOut = sqlite3MallocZero( pVfs->mxPathname+1 );
+    if( !zOut ){
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    if( cygwin_conv_path(
+            (osIsNT() ? CCP_POSIX_TO_WIN_W : CCP_POSIX_TO_WIN_A),
+            zRelative, zOut, pVfs->mxPathname+1)<0 ){
+      sqlite3_free(zOut);
+      return winLogError(SQLITE_CANTOPEN_CONVPATH, (DWORD)errno,
+                         "winFullPathname2", zRelative);
+    }else{
+      char *zUtf8 = winConvertToUtf8Filename(zOut);
+      if( !zUtf8 ){
+        sqlite3_free(zOut);
+        return SQLITE_IOERR_NOMEM_BKPT;
+      }
+      sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zUtf8);
+      sqlite3_free(zUtf8);
+      sqlite3_free(zOut);
+    }
+  }
+  return SQLITE_OK;
+#endif
+
+#if (SQLITE_OS_WINCE || SQLITE_OS_WINRT) && !defined(__CYGWIN__)
+  SimulateIOError( return SQLITE_ERROR );
+  /* WinCE has no concept of a relative pathname, or so I am told. */
+  /* WinRT has no way to convert a relative path to an absolute one. */
+  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
+    /*
+    ** NOTE: We are dealing with a relative path name and the data
+    **       directory has been set.  Therefore, use it as the basis
+    **       for converting the relative path name to an absolute
+    **       one by prepending the data directory and a backslash.
+    */
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s%c%s",
+                     sqlite3_data_directory, winGetDirSep(), zRelative);
+  }else{
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zRelative);
+  }
+  return SQLITE_OK;
+#endif
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && !defined(__CYGWIN__)
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing. This function could fail if, for example, the
+  ** current working directory has been unlinked.
+  */
+  SimulateIOError( return SQLITE_ERROR );
+  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
+    /*
+    ** NOTE: We are dealing with a relative path name and the data
+    **       directory has been set.  Therefore, use it as the basis
+    **       for converting the relative path name to an absolute
+    **       one by prepending the data directory and a backslash.
+    */
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s%c%s",
+                     sqlite3_data_directory, winGetDirSep(), zRelative);
+    return SQLITE_OK;
+  }
+  zConverted = winConvertFromUtf8Filename(zRelative);
+  if( zConverted==0 ){
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+  if( osIsNT() ){
+    LPWSTR zTemp;
+    nByte = osGetFullPathNameW((LPCWSTR)zConverted, 0, 0, 0);
+    if( nByte==0 ){
+      sqlite3_free(zConverted);
+      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
+                         "winFullPathname1", zRelative);
+    }
+    nByte += 3;
+    zTemp = sqlite3MallocZero( nByte*sizeof(zTemp[0]) );
+    if( zTemp==0 ){
+      sqlite3_free(zConverted);
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    nByte = osGetFullPathNameW((LPCWSTR)zConverted, nByte, zTemp, 0);
+    if( nByte==0 ){
+      sqlite3_free(zConverted);
+      sqlite3_free(zTemp);
+      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
+                         "winFullPathname2", zRelative);
+    }
+    sqlite3_free(zConverted);
+    zOut = winUnicodeToUtf8(zTemp);
+    sqlite3_free(zTemp);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    char *zTemp;
+    nByte = osGetFullPathNameA((char*)zConverted, 0, 0, 0);
+    if( nByte==0 ){
+      sqlite3_free(zConverted);
+      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
+                         "winFullPathname3", zRelative);
+    }
+    nByte += 3;
+    zTemp = sqlite3MallocZero( nByte*sizeof(zTemp[0]) );
+    if( zTemp==0 ){
+      sqlite3_free(zConverted);
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    nByte = osGetFullPathNameA((char*)zConverted, nByte, zTemp, 0);
+    if( nByte==0 ){
+      sqlite3_free(zConverted);
+      sqlite3_free(zTemp);
+      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
+                         "winFullPathname4", zRelative);
+    }
+    sqlite3_free(zConverted);
+    zOut = winMbcsToUtf8(zTemp, osAreFileApisANSI());
+    sqlite3_free(zTemp);
+  }
+#endif
+  if( zOut ){
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zOut);
+    sqlite3_free(zOut);
+    return SQLITE_OK;
+  }else{
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+#endif
+}
+static int winFullPathname(
+  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
+  const char *zRelative,        /* Possibly relative input path */
+  int nFull,                    /* Size of output buffer in bytes */
+  char *zFull                   /* Output buffer */
+){
+  int rc;
+  MUTEX_LOGIC( sqlite3_mutex *pMutex; )
+  MUTEX_LOGIC( pMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR); )
+  sqlite3_mutex_enter(pMutex);
+  rc = winFullPathnameNoMutex(pVfs, zRelative, nFull, zFull);
+  sqlite3_mutex_leave(pMutex);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Interfaces for opening a shared library, finding entry points
+** within the shared library, and closing the shared library.
+*/
+static void *winDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
+  HANDLE h;
+#if defined(__CYGWIN__)
+  int nFull = pVfs->mxPathname+1;
+  char *zFull = sqlite3MallocZero( nFull );
+  void *zConverted = 0;
+  if( zFull==0 ){
+    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
+    return 0;
+  }
+  if( winFullPathname(pVfs, zFilename, nFull, zFull)!=SQLITE_OK ){
+    sqlite3_free(zFull);
+    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
+    return 0;
+  }
+  zConverted = winConvertFromUtf8Filename(zFull);
+  sqlite3_free(zFull);
+#else
+  void *zConverted = winConvertFromUtf8Filename(zFilename);
+  UNUSED_PARAMETER(pVfs);
+#endif
+  if( zConverted==0 ){
+    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
+    return 0;
+  }
+  if( osIsNT() ){
+#if SQLITE_OS_WINRT
+    h = osLoadPackagedLibrary((LPCWSTR)zConverted, 0);
+#else
+    h = osLoadLibraryW((LPCWSTR)zConverted);
+#endif
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    h = osLoadLibraryA((char*)zConverted);
+  }
+#endif
+  OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)h));
+  sqlite3_free(zConverted);
+  return (void*)h;
+}
+static void winDlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
+  UNUSED_PARAMETER(pVfs);
+  winGetLastErrorMsg(osGetLastError(), nBuf, zBufOut);
+}
+static void (*winDlSym(sqlite3_vfs *pVfs,void *pH,const char *zSym))(void){
+  FARPROC proc;
+  UNUSED_PARAMETER(pVfs);
+  proc = osGetProcAddressA((HANDLE)pH, zSym);
+  OSTRACE(("DLSYM handle=%p, symbol=%s, address=%p\n",
+           (void*)pH, zSym, (void*)proc));
+  return (void(*)(void))proc;
+}
+static void winDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  UNUSED_PARAMETER(pVfs);
+  osFreeLibrary((HANDLE)pHandle);
+  OSTRACE(("DLCLOSE handle=%p\n", (void*)pHandle));
+}
+#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
+  #define winDlOpen  0
+  #define winDlError 0
+  #define winDlSym   0
+  #define winDlClose 0
+#endif
+
+/* State information for the randomness gatherer. */
+typedef struct EntropyGatherer EntropyGatherer;
+struct EntropyGatherer {
+  unsigned char *a;   /* Gather entropy into this buffer */
+  int na;             /* Size of a[] in bytes */
+  int i;              /* XOR next input into a[i] */
+  int nXor;           /* Number of XOR operations done */
+};
+
+#if !defined(SQLITE_TEST) && !defined(SQLITE_OMIT_RANDOMNESS)
+/* Mix sz bytes of entropy into p. */
+static void xorMemory(EntropyGatherer *p, unsigned char *x, int sz){
+  int j, k;
+  for(j=0, k=p->i; j<sz; j++){
+    p->a[k++] ^= x[j];
+    if( k>=p->na ) k = 0;
+  }
+  p->i = k;
+  p->nXor += sz;
+}
+#endif /* !defined(SQLITE_TEST) && !defined(SQLITE_OMIT_RANDOMNESS) */
+
+/*
+** Write up to nBuf bytes of randomness into zBuf.
+*/
+static int winRandomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+#if defined(SQLITE_TEST) || defined(SQLITE_OMIT_RANDOMNESS)
+  UNUSED_PARAMETER(pVfs);
+  memset(zBuf, 0, nBuf);
+  return nBuf;
+#else
+  EntropyGatherer e;
+  UNUSED_PARAMETER(pVfs);
+  memset(zBuf, 0, nBuf);
+  e.a = (unsigned char*)zBuf;
+  e.na = nBuf;
+  e.nXor = 0;
+  e.i = 0;
+  {
+    SYSTEMTIME x;
+    osGetSystemTime(&x);
+    xorMemory(&e, (unsigned char*)&x, sizeof(SYSTEMTIME));
+  }
+  {
+    DWORD pid = osGetCurrentProcessId();
+    xorMemory(&e, (unsigned char*)&pid, sizeof(DWORD));
+  }
+#if SQLITE_OS_WINRT
+  {
+    ULONGLONG cnt = osGetTickCount64();
+    xorMemory(&e, (unsigned char*)&cnt, sizeof(ULONGLONG));
+  }
+#else
+  {
+    DWORD cnt = osGetTickCount();
+    xorMemory(&e, (unsigned char*)&cnt, sizeof(DWORD));
+  }
+#endif /* SQLITE_OS_WINRT */
+  {
+    LARGE_INTEGER i;
+    osQueryPerformanceCounter(&i);
+    xorMemory(&e, (unsigned char*)&i, sizeof(LARGE_INTEGER));
+  }
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_WIN32_USE_UUID
+  {
+    UUID id;
+    memset(&id, 0, sizeof(UUID));
+    osUuidCreate(&id);
+    xorMemory(&e, (unsigned char*)&id, sizeof(UUID));
+    memset(&id, 0, sizeof(UUID));
+    osUuidCreateSequential(&id);
+    xorMemory(&e, (unsigned char*)&id, sizeof(UUID));
+  }
+#endif /* !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_WIN32_USE_UUID */
+  return e.nXor>nBuf ? nBuf : e.nXor;
+#endif /* defined(SQLITE_TEST) || defined(SQLITE_OMIT_RANDOMNESS) */
+}
+
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+*/
+static int winSleep(sqlite3_vfs *pVfs, int microsec){
+  sqlite3_win32_sleep((microsec+999)/1000);
+  UNUSED_PARAMETER(pVfs);
+  return ((microsec+999)/1000)*1000;
+}
+
+/*
+** The following variable, if set to a non-zero value, is interpreted as
+** the number of seconds since 1970 and is used to set the result of
+** sqlite3OsCurrentTime() during testing.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_current_time = 0;  /* Fake system time in seconds since 1970. */
+#endif
+
+/*
+** Find the current time (in Universal Coordinated Time).  Write into *piNow
+** the current time and date as a Julian Day number times 86_400_000.  In
+** other words, write into *piNow the number of milliseconds since the Julian
+** epoch of noon in Greenwich on November 24, 4714 B.C according to the
+** proleptic Gregorian calendar.
+**
+** On success, return SQLITE_OK.  Return SQLITE_ERROR if the time and date
+** cannot be found.
+*/
+static int winCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *piNow){
+  /* FILETIME structure is a 64-bit value representing the number of
+     100-nanosecond intervals since January 1, 1601 (= JD 2305813.5).
+  */
+  FILETIME ft;
+  static const sqlite3_int64 winFiletimeEpoch = 23058135*(sqlite3_int64)8640000;
+#ifdef SQLITE_TEST
+  static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+#endif
+  /* 2^32 - to avoid use of LL and warnings in gcc */
+  static const sqlite3_int64 max32BitValue =
+      (sqlite3_int64)2000000000 + (sqlite3_int64)2000000000 +
+      (sqlite3_int64)294967296;
+
+#if SQLITE_OS_WINCE
+  SYSTEMTIME time;
+  osGetSystemTime(&time);
+  /* if SystemTimeToFileTime() fails, it returns zero. */
+  if (!osSystemTimeToFileTime(&time,&ft)){
+    return SQLITE_ERROR;
+  }
+#else
+  osGetSystemTimeAsFileTime( &ft );
+#endif
+
+  *piNow = winFiletimeEpoch +
+            ((((sqlite3_int64)ft.dwHighDateTime)*max32BitValue) +
+               (sqlite3_int64)ft.dwLowDateTime)/(sqlite3_int64)10000;
+
+#ifdef SQLITE_TEST
+  if( sqlite3_current_time ){
+    *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch;
+  }
+#endif
+  UNUSED_PARAMETER(pVfs);
+  return SQLITE_OK;
+}
+
+/*
+** Find the current time (in Universal Coordinated Time).  Write the
+** current time and date as a Julian Day number into *prNow and
+** return 0.  Return 1 if the time and date cannot be found.
+*/
+static int winCurrentTime(sqlite3_vfs *pVfs, double *prNow){
+  int rc;
+  sqlite3_int64 i;
+  rc = winCurrentTimeInt64(pVfs, &i);
+  if( !rc ){
+    *prNow = i/86400000.0;
+  }
+  return rc;
+}
+
+/*
+** The idea is that this function works like a combination of
+** GetLastError() and FormatMessage() on Windows (or errno and
+** strerror_r() on Unix). After an error is returned by an OS
+** function, SQLite calls this function with zBuf pointing to
+** a buffer of nBuf bytes. The OS layer should populate the
+** buffer with a nul-terminated UTF-8 encoded error message
+** describing the last IO error to have occurred within the calling
+** thread.
+**
+** If the error message is too large for the supplied buffer,
+** it should be truncated. The return value of xGetLastError
+** is zero if the error message fits in the buffer, or non-zero
+** otherwise (if the message was truncated). If non-zero is returned,
+** then it is not necessary to include the nul-terminator character
+** in the output buffer.
+**
+** Not supplying an error message will have no adverse effect
+** on SQLite. It is fine to have an implementation that never
+** returns an error message:
+**
+**   int xGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+**     assert(zBuf[0]=='\0');
+**     return 0;
+**   }
+**
+** However if an error message is supplied, it will be incorporated
+** by sqlite into the error message available to the user using
+** sqlite3_errmsg(), possibly making IO errors easier to debug.
+*/
+static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+  DWORD e = osGetLastError();
+  UNUSED_PARAMETER(pVfs);
+  if( nBuf>0 ) winGetLastErrorMsg(e, nBuf, zBuf);
+  return e;
+}
+
+/*
+** Initialize and deinitialize the operating system interface.
+*/
+SQLITE_API int sqlite3_os_init(void){
+  static sqlite3_vfs winVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WIN32_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32",               /* zName */
+    &winAppData,           /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  static sqlite3_vfs winLongPathVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WINNT_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32-longpath",      /* zName */
+    &winAppData,           /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#endif
+  static sqlite3_vfs winNolockVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WIN32_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32-none",          /* zName */
+    &winNolockAppData,     /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  static sqlite3_vfs winLongPathNolockVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WINNT_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32-longpath-none", /* zName */
+    &winNolockAppData,     /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#endif
+
+  /* Double-check that the aSyscall[] array has been constructed
+  ** correctly.  See ticket [bb3a86e890c8e96ab] */
+  assert( ArraySize(aSyscall)==80 );
+
+  /* get memory map allocation granularity */
+  memset(&winSysInfo, 0, sizeof(SYSTEM_INFO));
+#if SQLITE_OS_WINRT
+  osGetNativeSystemInfo(&winSysInfo);
+#else
+  osGetSystemInfo(&winSysInfo);
+#endif
+  assert( winSysInfo.dwAllocationGranularity>0 );
+  assert( winSysInfo.dwPageSize>0 );
+
+  sqlite3_vfs_register(&winVfs, 1);
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  sqlite3_vfs_register(&winLongPathVfs, 0);
+#endif
+
+  sqlite3_vfs_register(&winNolockVfs, 0);
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  sqlite3_vfs_register(&winLongPathNolockVfs, 0);
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+  winBigLock = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
+#endif
+
+  return SQLITE_OK;
+}
+
+SQLITE_API int sqlite3_os_end(void){
+#if SQLITE_OS_WINRT
+  if( sleepObj!=NULL ){
+    osCloseHandle(sleepObj);
+    sleepObj = NULL;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+  winBigLock = 0;
+#endif
+
+  return SQLITE_OK;
+}
+
+#endif /* SQLITE_OS_WIN */
+
+/************** End of os_win.c **********************************************/
+/************** Begin file memdb.c *******************************************/
+/*
+** 2016-09-07
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file implements an in-memory VFS. A database is held as a contiguous
+** block of memory.
+**
+** This file also implements interface sqlite3_serialize() and
+** sqlite3_deserialize().
+*/
+/* #include "sqliteInt.h" */
+#ifndef SQLITE_OMIT_DESERIALIZE
+
+/*
+** Forward declaration of objects used by this utility
+*/
+typedef struct sqlite3_vfs MemVfs;
+typedef struct MemFile MemFile;
+typedef struct MemStore MemStore;
+
+/* Access to a lower-level VFS that (might) implement dynamic loading,
+** access to randomness, etc.
+*/
+#define ORIGVFS(p) ((sqlite3_vfs*)((p)->pAppData))
+
+/* Storage for a memdb file.
+**
+** An memdb object can be shared or separate.  Shared memdb objects can be
+** used by more than one database connection.  Mutexes are used by shared
+** memdb objects to coordinate access.  Separate memdb objects are only
+** connected to a single database connection and do not require additional
+** mutexes.
+**
+** Shared memdb objects have .zFName!=0 and .pMutex!=0.  They are created
+** using "file:/name?vfs=memdb".  The first character of the name must be
+** "/" or else the object will be a separate memdb object.  All shared
+** memdb objects are stored in memdb_g.apMemStore[] in an arbitrary order.
+**
+** Separate memdb objects are created using a name that does not begin
+** with "/" or using sqlite3_deserialize().
+**
+** Access rules for shared MemStore objects:
+**
+**   *  .zFName is initialized when the object is created and afterwards
+**      is unchanged until the object is destroyed.  So it can be accessed
+**      at any time as long as we know the object is not being destroyed,
+**      which means while either the SQLITE_MUTEX_STATIC_VFS1 or
+**      .pMutex is held or the object is not part of memdb_g.apMemStore[].
+**
+**   *  Can .pMutex can only be changed while holding the
+**      SQLITE_MUTEX_STATIC_VFS1 mutex or while the object is not part
+**      of memdb_g.apMemStore[].
+**
+**   *  Other fields can only be changed while holding the .pMutex mutex
+**      or when the .nRef is less than zero and the object is not part of
+**      memdb_g.apMemStore[].
+**
+**   *  The .aData pointer has the added requirement that it can can only
+**      be changed (for resizing) when nMmap is zero.
+**
+*/
+struct MemStore {
+  sqlite3_int64 sz;               /* Size of the file */
+  sqlite3_int64 szAlloc;          /* Space allocated to aData */
+  sqlite3_int64 szMax;            /* Maximum allowed size of the file */
+  unsigned char *aData;           /* content of the file */
+  sqlite3_mutex *pMutex;          /* Used by shared stores only */
+  int nMmap;                      /* Number of memory mapped pages */
+  unsigned mFlags;                /* Flags */
+  int nRdLock;                    /* Number of readers */
+  int nWrLock;                    /* Number of writers.  (Always 0 or 1) */
+  int nRef;                       /* Number of users of this MemStore */
+  char *zFName;                   /* The filename for shared stores */
+};
+
+/* An open file */
+struct MemFile {
+  sqlite3_file base;              /* IO methods */
+  MemStore *pStore;               /* The storage */
+  int eLock;                      /* Most recent lock against this file */
+};
+
+/*
+** File-scope variables for holding the memdb files that are accessible
+** to multiple database connections in separate threads.
+**
+** Must hold SQLITE_MUTEX_STATIC_VFS1 to access any part of this object.
+*/
+static struct MemFS {
+  int nMemStore;                  /* Number of shared MemStore objects */
+  MemStore **apMemStore;          /* Array of all shared MemStore objects */
+} memdb_g;
+
+/*
+** Methods for MemFile
+*/
+static int memdbClose(sqlite3_file*);
+static int memdbRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int memdbWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
+static int memdbTruncate(sqlite3_file*, sqlite3_int64 size);
+static int memdbSync(sqlite3_file*, int flags);
+static int memdbFileSize(sqlite3_file*, sqlite3_int64 *pSize);
+static int memdbLock(sqlite3_file*, int);
+static int memdbUnlock(sqlite3_file*, int);
+/* static int memdbCheckReservedLock(sqlite3_file*, int *pResOut);// not used */
+static int memdbFileControl(sqlite3_file*, int op, void *pArg);
+/* static int memdbSectorSize(sqlite3_file*); // not used */
+static int memdbDeviceCharacteristics(sqlite3_file*);
+static int memdbFetch(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
+static int memdbUnfetch(sqlite3_file*, sqlite3_int64 iOfst, void *p);
+
+/*
+** Methods for MemVfs
+*/
+static int memdbOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
+/* static int memdbDelete(sqlite3_vfs*, const char *zName, int syncDir); */
+static int memdbAccess(sqlite3_vfs*, const char *zName, int flags, int *);
+static int memdbFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
+static void *memdbDlOpen(sqlite3_vfs*, const char *zFilename);
+static void memdbDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
+static void (*memdbDlSym(sqlite3_vfs *pVfs, void *p, const char*zSym))(void);
+static void memdbDlClose(sqlite3_vfs*, void*);
+static int memdbRandomness(sqlite3_vfs*, int nByte, char *zOut);
+static int memdbSleep(sqlite3_vfs*, int microseconds);
+/* static int memdbCurrentTime(sqlite3_vfs*, double*); */
+static int memdbGetLastError(sqlite3_vfs*, int, char *);
+static int memdbCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
+
+static sqlite3_vfs memdb_vfs = {
+  2,                           /* iVersion */
+  0,                           /* szOsFile (set when registered) */
+  1024,                        /* mxPathname */
+  0,                           /* pNext */
+  "memdb",                     /* zName */
+  0,                           /* pAppData (set when registered) */
+  memdbOpen,                   /* xOpen */
+  0, /* memdbDelete, */        /* xDelete */
+  memdbAccess,                 /* xAccess */
+  memdbFullPathname,           /* xFullPathname */
+  memdbDlOpen,                 /* xDlOpen */
+  memdbDlError,                /* xDlError */
+  memdbDlSym,                  /* xDlSym */
+  memdbDlClose,                /* xDlClose */
+  memdbRandomness,             /* xRandomness */
+  memdbSleep,                  /* xSleep */
+  0, /* memdbCurrentTime, */   /* xCurrentTime */
+  memdbGetLastError,           /* xGetLastError */
+  memdbCurrentTimeInt64,       /* xCurrentTimeInt64 */
+  0,                           /* xSetSystemCall */
+  0,                           /* xGetSystemCall */
+  0,                           /* xNextSystemCall */
+};
+
+static const sqlite3_io_methods memdb_io_methods = {
+  3,                              /* iVersion */
+  memdbClose,                      /* xClose */
+  memdbRead,                       /* xRead */
+  memdbWrite,                      /* xWrite */
+  memdbTruncate,                   /* xTruncate */
+  memdbSync,                       /* xSync */
+  memdbFileSize,                   /* xFileSize */
+  memdbLock,                       /* xLock */
+  memdbUnlock,                     /* xUnlock */
+  0, /* memdbCheckReservedLock, */ /* xCheckReservedLock */
+  memdbFileControl,                /* xFileControl */
+  0, /* memdbSectorSize,*/         /* xSectorSize */
+  memdbDeviceCharacteristics,      /* xDeviceCharacteristics */
+  0,                               /* xShmMap */
+  0,                               /* xShmLock */
+  0,                               /* xShmBarrier */
+  0,                               /* xShmUnmap */
+  memdbFetch,                      /* xFetch */
+  memdbUnfetch                     /* xUnfetch */
+};
+
+/*
+** Enter/leave the mutex on a MemStore
+*/
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE==0
+static void memdbEnter(MemStore *p){
+  UNUSED_PARAMETER(p);
+}
+static void memdbLeave(MemStore *p){
+  UNUSED_PARAMETER(p);
+}
+#else
+static void memdbEnter(MemStore *p){
+  sqlite3_mutex_enter(p->pMutex);
+}
+static void memdbLeave(MemStore *p){
+  sqlite3_mutex_leave(p->pMutex);
+}
+#endif
+
+
+
+/*
+** Close an memdb-file.
+** Free the underlying MemStore object when its refcount drops to zero
+** or less.
+*/
+static int memdbClose(sqlite3_file *pFile){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  if( p->zFName ){
+    int i;
+#ifndef SQLITE_MUTEX_OMIT
+    sqlite3_mutex *pVfsMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
+#endif
+    sqlite3_mutex_enter(pVfsMutex);
+    for(i=0; ALWAYS(i<memdb_g.nMemStore); i++){
+      if( memdb_g.apMemStore[i]==p ){
+        memdbEnter(p);
+        if( p->nRef==1 ){
+          memdb_g.apMemStore[i] = memdb_g.apMemStore[--memdb_g.nMemStore];
+          if( memdb_g.nMemStore==0 ){
+            sqlite3_free(memdb_g.apMemStore);
+            memdb_g.apMemStore = 0;
+          }
+        }
+        break;
+      }
+    }
+    sqlite3_mutex_leave(pVfsMutex);
+  }else{
+    memdbEnter(p);
+  }
+  p->nRef--;
+  if( p->nRef<=0 ){
+    if( p->mFlags & SQLITE_DESERIALIZE_FREEONCLOSE ){
+      sqlite3_free(p->aData);
+    }
+    memdbLeave(p);
+    sqlite3_mutex_free(p->pMutex);
+    sqlite3_free(p);
+  }else{
+    memdbLeave(p);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Read data from an memdb-file.
+*/
+static int memdbRead(
+  sqlite3_file *pFile,
+  void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  memdbEnter(p);
+  if( iOfst+iAmt>p->sz ){
+    memset(zBuf, 0, iAmt);
+    if( iOfst<p->sz ) memcpy(zBuf, p->aData+iOfst, p->sz - iOfst);
+    memdbLeave(p);
+    return SQLITE_IOERR_SHORT_READ;
+  }
+  memcpy(zBuf, p->aData+iOfst, iAmt);
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Try to enlarge the memory allocation to hold at least sz bytes
+*/
+static int memdbEnlarge(MemStore *p, sqlite3_int64 newSz){
+  unsigned char *pNew;
+  if( (p->mFlags & SQLITE_DESERIALIZE_RESIZEABLE)==0 || NEVER(p->nMmap>0) ){
+    return SQLITE_FULL;
+  }
+  if( newSz>p->szMax ){
+    return SQLITE_FULL;
+  }
+  newSz *= 2;
+  if( newSz>p->szMax ) newSz = p->szMax;
+  pNew = sqlite3Realloc(p->aData, newSz);
+  if( pNew==0 ) return SQLITE_IOERR_NOMEM;
+  p->aData = pNew;
+  p->szAlloc = newSz;
+  return SQLITE_OK;
+}
+
+/*
+** Write data to an memdb-file.
+*/
+static int memdbWrite(
+  sqlite3_file *pFile,
+  const void *z,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  memdbEnter(p);
+  if( NEVER(p->mFlags & SQLITE_DESERIALIZE_READONLY) ){
+    /* Can't happen: memdbLock() will return SQLITE_READONLY before
+    ** reaching this point */
+    memdbLeave(p);
+    return SQLITE_IOERR_WRITE;
+  }
+  if( iOfst+iAmt>p->sz ){
+    int rc;
+    if( iOfst+iAmt>p->szAlloc
+     && (rc = memdbEnlarge(p, iOfst+iAmt))!=SQLITE_OK
+    ){
+      memdbLeave(p);
+      return rc;
+    }
+    if( iOfst>p->sz ) memset(p->aData+p->sz, 0, iOfst-p->sz);
+    p->sz = iOfst+iAmt;
+  }
+  memcpy(p->aData+iOfst, z, iAmt);
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Truncate an memdb-file.
+**
+** In rollback mode (which is always the case for memdb, as it does not
+** support WAL mode) the truncate() method is only used to reduce
+** the size of a file, never to increase the size.
+*/
+static int memdbTruncate(sqlite3_file *pFile, sqlite_int64 size){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  int rc = SQLITE_OK;
+  memdbEnter(p);
+  if( size>p->sz ){
+    /* This can only happen with a corrupt wal mode db */
+    rc = SQLITE_CORRUPT;
+  }else{
+    p->sz = size;
+  }
+  memdbLeave(p);
+  return rc;
+}
+
+/*
+** Sync an memdb-file.
+*/
+static int memdbSync(sqlite3_file *pFile, int flags){
+  UNUSED_PARAMETER(pFile);
+  UNUSED_PARAMETER(flags);
+  return SQLITE_OK;
+}
+
+/*
+** Return the current file-size of an memdb-file.
+*/
+static int memdbFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  memdbEnter(p);
+  *pSize = p->sz;
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Lock an memdb-file.
+*/
+static int memdbLock(sqlite3_file *pFile, int eLock){
+  MemFile *pThis = (MemFile*)pFile;
+  MemStore *p = pThis->pStore;
+  int rc = SQLITE_OK;
+  if( eLock<=pThis->eLock ) return SQLITE_OK;
+  memdbEnter(p);
+
+  assert( p->nWrLock==0 || p->nWrLock==1 );
+  assert( pThis->eLock<=SQLITE_LOCK_SHARED || p->nWrLock==1 );
+  assert( pThis->eLock==SQLITE_LOCK_NONE || p->nRdLock>=1 );
+
+  if( eLock>SQLITE_LOCK_SHARED && (p->mFlags & SQLITE_DESERIALIZE_READONLY) ){
+    rc = SQLITE_READONLY;
+  }else{
+    switch( eLock ){
+      case SQLITE_LOCK_SHARED: {
+        assert( pThis->eLock==SQLITE_LOCK_NONE );
+        if( p->nWrLock>0 ){
+          rc = SQLITE_BUSY;
+        }else{
+          p->nRdLock++;
+        }
+        break;
+      };
+
+      case SQLITE_LOCK_RESERVED:
+      case SQLITE_LOCK_PENDING: {
+        assert( pThis->eLock>=SQLITE_LOCK_SHARED );
+        if( ALWAYS(pThis->eLock==SQLITE_LOCK_SHARED) ){
+          if( p->nWrLock>0 ){
+            rc = SQLITE_BUSY;
+          }else{
+            p->nWrLock = 1;
+          }
+        }
+        break;
+      }
+
+      default: {
+        assert(  eLock==SQLITE_LOCK_EXCLUSIVE );
+        assert( pThis->eLock>=SQLITE_LOCK_SHARED );
+        if( p->nRdLock>1 ){
+          rc = SQLITE_BUSY;
+        }else if( pThis->eLock==SQLITE_LOCK_SHARED ){
+          p->nWrLock = 1;
+        }
+        break;
+      }
+    }
+  }
+  if( rc==SQLITE_OK ) pThis->eLock = eLock;
+  memdbLeave(p);
+  return rc;
+}
+
+/*
+** Unlock an memdb-file.
+*/
+static int memdbUnlock(sqlite3_file *pFile, int eLock){
+  MemFile *pThis = (MemFile*)pFile;
+  MemStore *p = pThis->pStore;
+  if( eLock>=pThis->eLock ) return SQLITE_OK;
+  memdbEnter(p);
+
+  assert( eLock==SQLITE_LOCK_SHARED || eLock==SQLITE_LOCK_NONE );
+  if( eLock==SQLITE_LOCK_SHARED ){
+    if( ALWAYS(pThis->eLock>SQLITE_LOCK_SHARED) ){
+      p->nWrLock--;
+    }
+  }else{
+    if( pThis->eLock>SQLITE_LOCK_SHARED ){
+      p->nWrLock--;
+    }
+    p->nRdLock--;
+  }
+
+  pThis->eLock = eLock;
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+#if 0
+/*
+** This interface is only used for crash recovery, which does not
+** occur on an in-memory database.
+*/
+static int memdbCheckReservedLock(sqlite3_file *pFile, int *pResOut){
+  *pResOut = 0;
+  return SQLITE_OK;
+}
+#endif
+
+
+/*
+** File control method. For custom operations on an memdb-file.
+*/
+static int memdbFileControl(sqlite3_file *pFile, int op, void *pArg){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  int rc = SQLITE_NOTFOUND;
+  memdbEnter(p);
+  if( op==SQLITE_FCNTL_VFSNAME ){
+    *(char**)pArg = sqlite3_mprintf("memdb(%p,%lld)", p->aData, p->sz);
+    rc = SQLITE_OK;
+  }
+  if( op==SQLITE_FCNTL_SIZE_LIMIT ){
+    sqlite3_int64 iLimit = *(sqlite3_int64*)pArg;
+    if( iLimit<p->sz ){
+      if( iLimit<0 ){
+        iLimit = p->szMax;
+      }else{
+        iLimit = p->sz;
+      }
+    }
+    p->szMax = iLimit;
+    *(sqlite3_int64*)pArg = iLimit;
+    rc = SQLITE_OK;
+  }
+  memdbLeave(p);
+  return rc;
+}
+
+#if 0  /* Not used because of SQLITE_IOCAP_POWERSAFE_OVERWRITE */
+/*
+** Return the sector-size in bytes for an memdb-file.
+*/
+static int memdbSectorSize(sqlite3_file *pFile){
+  return 1024;
+}
+#endif
+
+/*
+** Return the device characteristic flags supported by an memdb-file.
+*/
+static int memdbDeviceCharacteristics(sqlite3_file *pFile){
+  UNUSED_PARAMETER(pFile);
+  return SQLITE_IOCAP_ATOMIC |
+         SQLITE_IOCAP_POWERSAFE_OVERWRITE |
+         SQLITE_IOCAP_SAFE_APPEND |
+         SQLITE_IOCAP_SEQUENTIAL;
+}
+
+/* Fetch a page of a memory-mapped file */
+static int memdbFetch(
+  sqlite3_file *pFile,
+  sqlite3_int64 iOfst,
+  int iAmt,
+  void **pp
+){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  memdbEnter(p);
+  if( iOfst+iAmt>p->sz || (p->mFlags & SQLITE_DESERIALIZE_RESIZEABLE)!=0 ){
+    *pp = 0;
+  }else{
+    p->nMmap++;
+    *pp = (void*)(p->aData + iOfst);
+  }
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/* Release a memory-mapped page */
+static int memdbUnfetch(sqlite3_file *pFile, sqlite3_int64 iOfst, void *pPage){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  UNUSED_PARAMETER(iOfst);
+  UNUSED_PARAMETER(pPage);
+  memdbEnter(p);
+  p->nMmap--;
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Open an mem file handle.
+*/
+static int memdbOpen(
+  sqlite3_vfs *pVfs,
+  const char *zName,
+  sqlite3_file *pFd,
+  int flags,
+  int *pOutFlags
+){
+  MemFile *pFile = (MemFile*)pFd;
+  MemStore *p = 0;
+  int szName;
+  UNUSED_PARAMETER(pVfs);
+
+  memset(pFile, 0, sizeof(*pFile));
+  szName = sqlite3Strlen30(zName);
+  if( szName>1 && (zName[0]=='/' || zName[0]=='\\') ){
+    int i;
+#ifndef SQLITE_MUTEX_OMIT
+    sqlite3_mutex *pVfsMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
+#endif
+    sqlite3_mutex_enter(pVfsMutex);
+    for(i=0; i<memdb_g.nMemStore; i++){
+      if( strcmp(memdb_g.apMemStore[i]->zFName,zName)==0 ){
+        p = memdb_g.apMemStore[i];
+        break;
+      }
+    }
+    if( p==0 ){
+      MemStore **apNew;
+      p = sqlite3Malloc( sizeof(*p) + szName + 3 );
+      if( p==0 ){
+        sqlite3_mutex_leave(pVfsMutex);
+        return SQLITE_NOMEM;
+      }
+      apNew = sqlite3Realloc(memdb_g.apMemStore,
+                             sizeof(apNew[0])*(memdb_g.nMemStore+1) );
+      if( apNew==0 ){
+        sqlite3_free(p);
+        sqlite3_mutex_leave(pVfsMutex);
+        return SQLITE_NOMEM;
+      }
+      apNew[memdb_g.nMemStore++] = p;
+      memdb_g.apMemStore = apNew;
+      memset(p, 0, sizeof(*p));
+      p->mFlags = SQLITE_DESERIALIZE_RESIZEABLE|SQLITE_DESERIALIZE_FREEONCLOSE;
+      p->szMax = sqlite3GlobalConfig.mxMemdbSize;
+      p->zFName = (char*)&p[1];
+      memcpy(p->zFName, zName, szName+1);
+      p->pMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+      if( p->pMutex==0 ){
+        memdb_g.nMemStore--;
+        sqlite3_free(p);
+        sqlite3_mutex_leave(pVfsMutex);
+        return SQLITE_NOMEM;
+      }
+      p->nRef = 1;
+      memdbEnter(p);
+    }else{
+      memdbEnter(p);
+      p->nRef++;
+    }
+    sqlite3_mutex_leave(pVfsMutex);
+  }else{
+    p = sqlite3Malloc( sizeof(*p) );
+    if( p==0 ){
+      return SQLITE_NOMEM;
+    }
+    memset(p, 0, sizeof(*p));
+    p->mFlags = SQLITE_DESERIALIZE_RESIZEABLE | SQLITE_DESERIALIZE_FREEONCLOSE;
+    p->szMax = sqlite3GlobalConfig.mxMemdbSize;
+  }
+  pFile->pStore = p;
+  if( pOutFlags!=0 ){
+    *pOutFlags = flags | SQLITE_OPEN_MEMORY;
+  }
+  pFd->pMethods = &memdb_io_methods;
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+#if 0 /* Only used to delete rollback journals, super-journals, and WAL
+      ** files, none of which exist in memdb.  So this routine is never used */
+/*
+** Delete the file located at zPath. If the dirSync argument is true,
+** ensure the file-system modifications are synced to disk before
+** returning.
+*/
+static int memdbDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  return SQLITE_IOERR_DELETE;
+}
+#endif
+
+/*
+** Test for access permissions. Return true if the requested permission
+** is available, or false otherwise.
+**
+** With memdb, no files ever exist on disk.  So always return false.
+*/
+static int memdbAccess(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int flags,
+  int *pResOut
+){
+  UNUSED_PARAMETER(pVfs);
+  UNUSED_PARAMETER(zPath);
+  UNUSED_PARAMETER(flags);
+  *pResOut = 0;
+  return SQLITE_OK;
+}
+
+/*
+** Populate buffer zOut with the full canonical pathname corresponding
+** to the pathname in zPath. zOut is guaranteed to point to a buffer
+** of at least (INST_MAX_PATHNAME+1) bytes.
+*/
+static int memdbFullPathname(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int nOut,
+  char *zOut
+){
+  UNUSED_PARAMETER(pVfs);
+  sqlite3_snprintf(nOut, zOut, "%s", zPath);
+  return SQLITE_OK;
+}
+
+/*
+** Open the dynamic library located at zPath and return a handle.
+*/
+static void *memdbDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  return ORIGVFS(pVfs)->xDlOpen(ORIGVFS(pVfs), zPath);
+}
+
+/*
+** Populate the buffer zErrMsg (size nByte bytes) with a human readable
+** utf-8 string describing the most recent error encountered associated
+** with dynamic libraries.
+*/
+static void memdbDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
+  ORIGVFS(pVfs)->xDlError(ORIGVFS(pVfs), nByte, zErrMsg);
+}
+
+/*
+** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
+*/
+static void (*memdbDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
+  return ORIGVFS(pVfs)->xDlSym(ORIGVFS(pVfs), p, zSym);
+}
+
+/*
+** Close the dynamic library handle pHandle.
+*/
+static void memdbDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  ORIGVFS(pVfs)->xDlClose(ORIGVFS(pVfs), pHandle);
+}
+
+/*
+** Populate the buffer pointed to by zBufOut with nByte bytes of
+** random data.
+*/
+static int memdbRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  return ORIGVFS(pVfs)->xRandomness(ORIGVFS(pVfs), nByte, zBufOut);
+}
+
+/*
+** Sleep for nMicro microseconds. Return the number of microseconds
+** actually slept.
+*/
+static int memdbSleep(sqlite3_vfs *pVfs, int nMicro){
+  return ORIGVFS(pVfs)->xSleep(ORIGVFS(pVfs), nMicro);
+}
+
+#if 0  /* Never used.  Modern cores only call xCurrentTimeInt64() */
+/*
+** Return the current time as a Julian Day number in *pTimeOut.
+*/
+static int memdbCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+  return ORIGVFS(pVfs)->xCurrentTime(ORIGVFS(pVfs), pTimeOut);
+}
+#endif
+
+static int memdbGetLastError(sqlite3_vfs *pVfs, int a, char *b){
+  return ORIGVFS(pVfs)->xGetLastError(ORIGVFS(pVfs), a, b);
+}
+static int memdbCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *p){
+  return ORIGVFS(pVfs)->xCurrentTimeInt64(ORIGVFS(pVfs), p);
+}
+
+/*
+** Translate a database connection pointer and schema name into a
+** MemFile pointer.
+*/
+static MemFile *memdbFromDbSchema(sqlite3 *db, const char *zSchema){
+  MemFile *p = 0;
+  MemStore *pStore;
+  int rc = sqlite3_file_control(db, zSchema, SQLITE_FCNTL_FILE_POINTER, &p);
+  if( rc ) return 0;
+  if( p->base.pMethods!=&memdb_io_methods ) return 0;
+  pStore = p->pStore;
+  memdbEnter(pStore);
+  if( pStore->zFName!=0 ) p = 0;
+  memdbLeave(pStore);
+  return p;
+}
+
+/*
+** Return the serialization of a database
+*/
+SQLITE_API unsigned char *sqlite3_serialize(
+  sqlite3 *db,              /* The database connection */
+  const char *zSchema,      /* Which database within the connection */
+  sqlite3_int64 *piSize,    /* Write size here, if not NULL */
+  unsigned int mFlags       /* Maybe SQLITE_SERIALIZE_NOCOPY */
+){
+  MemFile *p;
+  int iDb;
+  Btree *pBt;
+  sqlite3_int64 sz;
+  int szPage = 0;
+  sqlite3_stmt *pStmt = 0;
+  unsigned char *pOut;
+  char *zSql;
+  int rc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+
+  if( zSchema==0 ) zSchema = db->aDb[0].zDbSName;
+  p = memdbFromDbSchema(db, zSchema);
+  iDb = sqlite3FindDbName(db, zSchema);
+  if( piSize ) *piSize = -1;
+  if( iDb<0 ) return 0;
+  if( p ){
+    MemStore *pStore = p->pStore;
+    assert( pStore->pMutex==0 );
+    if( piSize ) *piSize = pStore->sz;
+    if( mFlags & SQLITE_SERIALIZE_NOCOPY ){
+      pOut = pStore->aData;
+    }else{
+      pOut = sqlite3_malloc64( pStore->sz );
+      if( pOut ) memcpy(pOut, pStore->aData, pStore->sz);
+    }
+    return pOut;
+  }
+  pBt = db->aDb[iDb].pBt;
+  if( pBt==0 ) return 0;
+  szPage = sqlite3BtreeGetPageSize(pBt);
+  zSql = sqlite3_mprintf("PRAGMA \"%w\".page_count", zSchema);
+  rc = zSql ? sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0) : SQLITE_NOMEM;
+  sqlite3_free(zSql);
+  if( rc ) return 0;
+  rc = sqlite3_step(pStmt);
+  if( rc!=SQLITE_ROW ){
+    pOut = 0;
+  }else{
+    sz = sqlite3_column_int64(pStmt, 0)*szPage;
+    if( sz==0 ){
+      sqlite3_reset(pStmt);
+      sqlite3_exec(db, "BEGIN IMMEDIATE; COMMIT;", 0, 0, 0);
+      rc = sqlite3_step(pStmt);
+      if( rc==SQLITE_ROW ){
+        sz = sqlite3_column_int64(pStmt, 0)*szPage;
+      }
+    }
+    if( piSize ) *piSize = sz;
+    if( mFlags & SQLITE_SERIALIZE_NOCOPY ){
+      pOut = 0;
+    }else{
+      pOut = sqlite3_malloc64( sz );
+      if( pOut ){
+        int nPage = sqlite3_column_int(pStmt, 0);
+        Pager *pPager = sqlite3BtreePager(pBt);
+        int pgno;
+        for(pgno=1; pgno<=nPage; pgno++){
+          DbPage *pPage = 0;
+          unsigned char *pTo = pOut + szPage*(sqlite3_int64)(pgno-1);
+          rc = sqlite3PagerGet(pPager, pgno, (DbPage**)&pPage, 0);
+          if( rc==SQLITE_OK ){
+            memcpy(pTo, sqlite3PagerGetData(pPage), szPage);
+          }else{
+            memset(pTo, 0, szPage);
+          }
+          sqlite3PagerUnref(pPage);
+        }
+      }
+    }
+  }
+  sqlite3_finalize(pStmt);
+  return pOut;
+}
+
+/* Convert zSchema to a MemDB and initialize its content.
+*/
+SQLITE_API int sqlite3_deserialize(
+  sqlite3 *db,            /* The database connection */
+  const char *zSchema,    /* Which DB to reopen with the deserialization */
+  unsigned char *pData,   /* The serialized database content */
+  sqlite3_int64 szDb,     /* Number bytes in the deserialization */
+  sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
+  unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
+){
+  MemFile *p;
+  char *zSql;
+  sqlite3_stmt *pStmt = 0;
+  int rc;
+  int iDb;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  if( szDb<0 ) return SQLITE_MISUSE_BKPT;
+  if( szBuf<0 ) return SQLITE_MISUSE_BKPT;
+#endif
+
+  sqlite3_mutex_enter(db->mutex);
+  if( zSchema==0 ) zSchema = db->aDb[0].zDbSName;
+  iDb = sqlite3FindDbName(db, zSchema);
+  testcase( iDb==1 );
+  if( iDb<2 && iDb!=0 ){
+    rc = SQLITE_ERROR;
+    goto end_deserialize;
+  }
+  zSql = sqlite3_mprintf("ATTACH x AS %Q", zSchema);
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+    sqlite3_free(zSql);
+  }
+  if( rc ) goto end_deserialize;
+  db->init.iDb = (u8)iDb;
+  db->init.reopenMemdb = 1;
+  rc = sqlite3_step(pStmt);
+  db->init.reopenMemdb = 0;
+  if( rc!=SQLITE_DONE ){
+    rc = SQLITE_ERROR;
+    goto end_deserialize;
+  }
+  p = memdbFromDbSchema(db, zSchema);
+  if( p==0 ){
+    rc = SQLITE_ERROR;
+  }else{
+    MemStore *pStore = p->pStore;
+    pStore->aData = pData;
+    pData = 0;
+    pStore->sz = szDb;
+    pStore->szAlloc = szBuf;
+    pStore->szMax = szBuf;
+    if( pStore->szMax<sqlite3GlobalConfig.mxMemdbSize ){
+      pStore->szMax = sqlite3GlobalConfig.mxMemdbSize;
+    }
+    pStore->mFlags = mFlags;
+    rc = SQLITE_OK;
+  }
+
+end_deserialize:
+  sqlite3_finalize(pStmt);
+  if( pData && (mFlags & SQLITE_DESERIALIZE_FREEONCLOSE)!=0 ){
+    sqlite3_free(pData);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Return true if the VFS is the memvfs.
+*/
+SQLITE_PRIVATE int sqlite3IsMemdb(const sqlite3_vfs *pVfs){
+  return pVfs==&memdb_vfs;
+}
+
+/*
+** This routine is called when the extension is loaded.
+** Register the new VFS.
+*/
+SQLITE_PRIVATE int sqlite3MemdbInit(void){
+  sqlite3_vfs *pLower = sqlite3_vfs_find(0);
+  unsigned int sz;
+  if( NEVER(pLower==0) ) return SQLITE_ERROR;
+  sz = pLower->szOsFile;
+  memdb_vfs.pAppData = pLower;
+  /* The following conditional can only be true when compiled for
+  ** Windows x86 and SQLITE_MAX_MMAP_SIZE=0.  We always leave
+  ** it in, to be safe, but it is marked as NO_TEST since there
+  ** is no way to reach it under most builds. */
+  if( sz<sizeof(MemFile) ) sz = sizeof(MemFile); /*NO_TEST*/
+  memdb_vfs.szOsFile = sz;
+  return sqlite3_vfs_register(&memdb_vfs, 0);
+}
+#endif /* SQLITE_OMIT_DESERIALIZE */
+
+/************** End of memdb.c ***********************************************/
+/************** Begin file bitvec.c ******************************************/
+/*
+** 2008 February 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements an object that represents a fixed-length
+** bitmap.  Bits are numbered starting with 1.
+**
+** A bitmap is used to record which pages of a database file have been
+** journalled during a transaction, or which pages have the "dont-write"
+** property.  Usually only a few pages are meet either condition.
+** So the bitmap is usually sparse and has low cardinality.
+** But sometimes (for example when during a DROP of a large table) most
+** or all of the pages in a database can get journalled.  In those cases,
+** the bitmap becomes dense with high cardinality.  The algorithm needs
+** to handle both cases well.
+**
+** The size of the bitmap is fixed when the object is created.
+**
+** All bits are clear when the bitmap is created.  Individual bits
+** may be set or cleared one at a time.
+**
+** Test operations are about 100 times more common that set operations.
+** Clear operations are exceedingly rare.  There are usually between
+** 5 and 500 set operations per Bitvec object, though the number of sets can
+** sometimes grow into tens of thousands or larger.  The size of the
+** Bitvec object is the number of pages in the database file at the
+** start of a transaction, and is thus usually less than a few thousand,
+** but can be as large as 2 billion for a really big database.
+*/
+/* #include "sqliteInt.h" */
+
+/* Size of the Bitvec structure in bytes. */
+#define BITVEC_SZ        512
+
+/* Round the union size down to the nearest pointer boundary, since that's how
+** it will be aligned within the Bitvec struct. */
+#define BITVEC_USIZE \
+    (((BITVEC_SZ-(3*sizeof(u32)))/sizeof(Bitvec*))*sizeof(Bitvec*))
+
+/* Type of the array "element" for the bitmap representation.
+** Should be a power of 2, and ideally, evenly divide into BITVEC_USIZE.
+** Setting this to the "natural word" size of your CPU may improve
+** performance. */
+#define BITVEC_TELEM     u8
+/* Size, in bits, of the bitmap element. */
+#define BITVEC_SZELEM    8
+/* Number of elements in a bitmap array. */
+#define BITVEC_NELEM     (BITVEC_USIZE/sizeof(BITVEC_TELEM))
+/* Number of bits in the bitmap array. */
+#define BITVEC_NBIT      (BITVEC_NELEM*BITVEC_SZELEM)
+
+/* Number of u32 values in hash table. */
+#define BITVEC_NINT      (BITVEC_USIZE/sizeof(u32))
+/* Maximum number of entries in hash table before
+** sub-dividing and re-hashing. */
+#define BITVEC_MXHASH    (BITVEC_NINT/2)
+/* Hashing function for the aHash representation.
+** Empirical testing showed that the *37 multiplier
+** (an arbitrary prime)in the hash function provided
+** no fewer collisions than the no-op *1. */
+#define BITVEC_HASH(X)   (((X)*1)%BITVEC_NINT)
+
+#define BITVEC_NPTR      (BITVEC_USIZE/sizeof(Bitvec *))
+
+
+/*
+** A bitmap is an instance of the following structure.
+**
+** This bitmap records the existence of zero or more bits
+** with values between 1 and iSize, inclusive.
+**
+** There are three possible representations of the bitmap.
+** If iSize<=BITVEC_NBIT, then Bitvec.u.aBitmap[] is a straight
+** bitmap.  The least significant bit is bit 1.
+**
+** If iSize>BITVEC_NBIT and iDivisor==0 then Bitvec.u.aHash[] is
+** a hash table that will hold up to BITVEC_MXHASH distinct values.
+**
+** Otherwise, the value i is redirected into one of BITVEC_NPTR
+** sub-bitmaps pointed to by Bitvec.u.apSub[].  Each subbitmap
+** handles up to iDivisor separate values of i.  apSub[0] holds
+** values between 1 and iDivisor.  apSub[1] holds values between
+** iDivisor+1 and 2*iDivisor.  apSub[N] holds values between
+** N*iDivisor+1 and (N+1)*iDivisor.  Each subbitmap is normalized
+** to hold deal with values between 1 and iDivisor.
+*/
+struct Bitvec {
+  u32 iSize;      /* Maximum bit index.  Max iSize is 4,294,967,296. */
+  u32 nSet;       /* Number of bits that are set - only valid for aHash
+                  ** element.  Max is BITVEC_NINT.  For BITVEC_SZ of 512,
+                  ** this would be 125. */
+  u32 iDivisor;   /* Number of bits handled by each apSub[] entry. */
+                  /* Should >=0 for apSub element. */
+                  /* Max iDivisor is max(u32) / BITVEC_NPTR + 1.  */
+                  /* For a BITVEC_SZ of 512, this would be 34,359,739. */
+  union {
+    BITVEC_TELEM aBitmap[BITVEC_NELEM];    /* Bitmap representation */
+    u32 aHash[BITVEC_NINT];      /* Hash table representation */
+    Bitvec *apSub[BITVEC_NPTR];  /* Recursive representation */
+  } u;
+};
+
+/*
+** Create a new bitmap object able to handle bits between 0 and iSize,
+** inclusive.  Return a pointer to the new object.  Return NULL if
+** malloc fails.
+*/
+SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32 iSize){
+  Bitvec *p;
+  assert( sizeof(*p)==BITVEC_SZ );
+  p = sqlite3MallocZero( sizeof(*p) );
+  if( p ){
+    p->iSize = iSize;
+  }
+  return p;
+}
+
+/*
+** Check to see if the i-th bit is set.  Return true or false.
+** If p is NULL (if the bitmap has not been created) or if
+** i is out of range, then return false.
+*/
+SQLITE_PRIVATE int sqlite3BitvecTestNotNull(Bitvec *p, u32 i){
+  assert( p!=0 );
+  i--;
+  if( i>=p->iSize ) return 0;
+  while( p->iDivisor ){
+    u32 bin = i/p->iDivisor;
+    i = i%p->iDivisor;
+    p = p->u.apSub[bin];
+    if (!p) {
+      return 0;
+    }
+  }
+  if( p->iSize<=BITVEC_NBIT ){
+    return (p->u.aBitmap[i/BITVEC_SZELEM] & (1<<(i&(BITVEC_SZELEM-1))))!=0;
+  } else{
+    u32 h = BITVEC_HASH(i++);
+    while( p->u.aHash[h] ){
+      if( p->u.aHash[h]==i ) return 1;
+      h = (h+1) % BITVEC_NINT;
+    }
+    return 0;
+  }
+}
+SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec *p, u32 i){
+  return p!=0 && sqlite3BitvecTestNotNull(p,i);
+}
+
+/*
+** Set the i-th bit.  Return 0 on success and an error code if
+** anything goes wrong.
+**
+** This routine might cause sub-bitmaps to be allocated.  Failing
+** to get the memory needed to hold the sub-bitmap is the only
+** that can go wrong with an insert, assuming p and i are valid.
+**
+** The calling function must ensure that p is a valid Bitvec object
+** and that the value for "i" is within range of the Bitvec object.
+** Otherwise the behavior is undefined.
+*/
+SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec *p, u32 i){
+  u32 h;
+  if( p==0 ) return SQLITE_OK;
+  assert( i>0 );
+  assert( i<=p->iSize );
+  i--;
+  while((p->iSize > BITVEC_NBIT) && p->iDivisor) {
+    u32 bin = i/p->iDivisor;
+    i = i%p->iDivisor;
+    if( p->u.apSub[bin]==0 ){
+      p->u.apSub[bin] = sqlite3BitvecCreate( p->iDivisor );
+      if( p->u.apSub[bin]==0 ) return SQLITE_NOMEM_BKPT;
+    }
+    p = p->u.apSub[bin];
+  }
+  if( p->iSize<=BITVEC_NBIT ){
+    p->u.aBitmap[i/BITVEC_SZELEM] |= 1 << (i&(BITVEC_SZELEM-1));
+    return SQLITE_OK;
+  }
+  h = BITVEC_HASH(i++);
+  /* if there wasn't a hash collision, and this doesn't */
+  /* completely fill the hash, then just add it without */
+  /* worrying about sub-dividing and re-hashing. */
+  if( !p->u.aHash[h] ){
+    if (p->nSet<(BITVEC_NINT-1)) {
+      goto bitvec_set_end;
+    } else {
+      goto bitvec_set_rehash;
+    }
+  }
+  /* there was a collision, check to see if it's already */
+  /* in hash, if not, try to find a spot for it */
+  do {
+    if( p->u.aHash[h]==i ) return SQLITE_OK;
+    h++;
+    if( h>=BITVEC_NINT ) h = 0;
+  } while( p->u.aHash[h] );
+  /* we didn't find it in the hash.  h points to the first */
+  /* available free spot. check to see if this is going to */
+  /* make our hash too "full".  */
+bitvec_set_rehash:
+  if( p->nSet>=BITVEC_MXHASH ){
+    unsigned int j;
+    int rc;
+    u32 *aiValues = sqlite3StackAllocRaw(0, sizeof(p->u.aHash));
+    if( aiValues==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }else{
+      memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
+      memset(p->u.apSub, 0, sizeof(p->u.apSub));
+      p->iDivisor = (p->iSize + BITVEC_NPTR - 1)/BITVEC_NPTR;
+      rc = sqlite3BitvecSet(p, i);
+      for(j=0; j<BITVEC_NINT; j++){
+        if( aiValues[j] ) rc |= sqlite3BitvecSet(p, aiValues[j]);
+      }
+      sqlite3StackFree(0, aiValues);
+      return rc;
+    }
+  }
+bitvec_set_end:
+  p->nSet++;
+  p->u.aHash[h] = i;
+  return SQLITE_OK;
+}
+
+/*
+** Clear the i-th bit.
+**
+** pBuf must be a pointer to at least BITVEC_SZ bytes of temporary storage
+** that BitvecClear can use to rebuilt its hash table.
+*/
+SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec *p, u32 i, void *pBuf){
+  if( p==0 ) return;
+  assert( i>0 );
+  i--;
+  while( p->iDivisor ){
+    u32 bin = i/p->iDivisor;
+    i = i%p->iDivisor;
+    p = p->u.apSub[bin];
+    if (!p) {
+      return;
+    }
+  }
+  if( p->iSize<=BITVEC_NBIT ){
+    p->u.aBitmap[i/BITVEC_SZELEM] &= ~(1 << (i&(BITVEC_SZELEM-1)));
+  }else{
+    unsigned int j;
+    u32 *aiValues = pBuf;
+    memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
+    memset(p->u.aHash, 0, sizeof(p->u.aHash));
+    p->nSet = 0;
+    for(j=0; j<BITVEC_NINT; j++){
+      if( aiValues[j] && aiValues[j]!=(i+1) ){
+        u32 h = BITVEC_HASH(aiValues[j]-1);
+        p->nSet++;
+        while( p->u.aHash[h] ){
+          h++;
+          if( h>=BITVEC_NINT ) h = 0;
+        }
+        p->u.aHash[h] = aiValues[j];
+      }
+    }
+  }
+}
+
+/*
+** Destroy a bitmap object.  Reclaim all memory used.
+*/
+SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec *p){
+  if( p==0 ) return;
+  if( p->iDivisor ){
+    unsigned int i;
+    for(i=0; i<BITVEC_NPTR; i++){
+      sqlite3BitvecDestroy(p->u.apSub[i]);
+    }
+  }
+  sqlite3_free(p);
+}
+
+/*
+** Return the value of the iSize parameter specified when Bitvec *p
+** was created.
+*/
+SQLITE_PRIVATE u32 sqlite3BitvecSize(Bitvec *p){
+  return p->iSize;
+}
+
+#ifndef SQLITE_UNTESTABLE
+/*
+** Let V[] be an array of unsigned characters sufficient to hold
+** up to N bits.  Let I be an integer between 0 and N.  0<=I<N.
+** Then the following macros can be used to set, clear, or test
+** individual bits within V.
+*/
+#define SETBIT(V,I)      V[I>>3] |= (1<<(I&7))
+#define CLEARBIT(V,I)    V[I>>3] &= ~(1<<(I&7))
+#define TESTBIT(V,I)     (V[I>>3]&(1<<(I&7)))!=0
+
+/*
+** This routine runs an extensive test of the Bitvec code.
+**
+** The input is an array of integers that acts as a program
+** to test the Bitvec.  The integers are opcodes followed
+** by 0, 1, or 3 operands, depending on the opcode.  Another
+** opcode follows immediately after the last operand.
+**
+** There are 6 opcodes numbered from 0 through 5.  0 is the
+** "halt" opcode and causes the test to end.
+**
+**    0          Halt and return the number of errors
+**    1 N S X    Set N bits beginning with S and incrementing by X
+**    2 N S X    Clear N bits beginning with S and incrementing by X
+**    3 N        Set N randomly chosen bits
+**    4 N        Clear N randomly chosen bits
+**    5 N S X    Set N bits from S increment X in array only, not in bitvec
+**
+** The opcodes 1 through 4 perform set and clear operations are performed
+** on both a Bitvec object and on a linear array of bits obtained from malloc.
+** Opcode 5 works on the linear array only, not on the Bitvec.
+** Opcode 5 is used to deliberately induce a fault in order to
+** confirm that error detection works.
+**
+** At the conclusion of the test the linear array is compared
+** against the Bitvec object.  If there are any differences,
+** an error is returned.  If they are the same, zero is returned.
+**
+** If a memory allocation error occurs, return -1.
+*/
+SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int sz, int *aOp){
+  Bitvec *pBitvec = 0;
+  unsigned char *pV = 0;
+  int rc = -1;
+  int i, nx, pc, op;
+  void *pTmpSpace;
+
+  /* Allocate the Bitvec to be tested and a linear array of
+  ** bits to act as the reference */
+  pBitvec = sqlite3BitvecCreate( sz );
+  pV = sqlite3MallocZero( (sz+7)/8 + 1 );
+  pTmpSpace = sqlite3_malloc64(BITVEC_SZ);
+  if( pBitvec==0 || pV==0 || pTmpSpace==0  ) goto bitvec_end;
+
+  /* NULL pBitvec tests */
+  sqlite3BitvecSet(0, 1);
+  sqlite3BitvecClear(0, 1, pTmpSpace);
+
+  /* Run the program */
+  pc = i = 0;
+  while( (op = aOp[pc])!=0 ){
+    switch( op ){
+      case 1:
+      case 2:
+      case 5: {
+        nx = 4;
+        i = aOp[pc+2] - 1;
+        aOp[pc+2] += aOp[pc+3];
+        break;
+      }
+      case 3:
+      case 4:
+      default: {
+        nx = 2;
+        sqlite3_randomness(sizeof(i), &i);
+        break;
+      }
+    }
+    if( (--aOp[pc+1]) > 0 ) nx = 0;
+    pc += nx;
+    i = (i & 0x7fffffff)%sz;
+    if( (op & 1)!=0 ){
+      SETBIT(pV, (i+1));
+      if( op!=5 ){
+        if( sqlite3BitvecSet(pBitvec, i+1) ) goto bitvec_end;
+      }
+    }else{
+      CLEARBIT(pV, (i+1));
+      sqlite3BitvecClear(pBitvec, i+1, pTmpSpace);
+    }
+  }
+
+  /* Test to make sure the linear array exactly matches the
+  ** Bitvec object.  Start with the assumption that they do
+  ** match (rc==0).  Change rc to non-zero if a discrepancy
+  ** is found.
+  */
+  rc = sqlite3BitvecTest(0,0) + sqlite3BitvecTest(pBitvec, sz+1)
+          + sqlite3BitvecTest(pBitvec, 0)
+          + (sqlite3BitvecSize(pBitvec) - sz);
+  for(i=1; i<=sz; i++){
+    if(  (TESTBIT(pV,i))!=sqlite3BitvecTest(pBitvec,i) ){
+      rc = i;
+      break;
+    }
+  }
+
+  /* Free allocated structure */
+bitvec_end:
+  sqlite3_free(pTmpSpace);
+  sqlite3_free(pV);
+  sqlite3BitvecDestroy(pBitvec);
+  return rc;
+}
+#endif /* SQLITE_UNTESTABLE */
+
+/************** End of bitvec.c **********************************************/
+/************** Begin file pcache.c ******************************************/
+/*
+** 2008 August 05
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements that page cache.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** A complete page cache is an instance of this structure.  Every
+** entry in the cache holds a single page of the database file.  The
+** btree layer only operates on the cached copy of the database pages.
+**
+** A page cache entry is "clean" if it exactly matches what is currently
+** on disk.  A page is "dirty" if it has been modified and needs to be
+** persisted to disk.
+**
+** pDirty, pDirtyTail, pSynced:
+**   All dirty pages are linked into the doubly linked list using
+**   PgHdr.pDirtyNext and pDirtyPrev. The list is maintained in LRU order
+**   such that p was added to the list more recently than p->pDirtyNext.
+**   PCache.pDirty points to the first (newest) element in the list and
+**   pDirtyTail to the last (oldest).
+**
+**   The PCache.pSynced variable is used to optimize searching for a dirty
+**   page to eject from the cache mid-transaction. It is better to eject
+**   a page that does not require a journal sync than one that does.
+**   Therefore, pSynced is maintained so that it *almost* always points
+**   to either the oldest page in the pDirty/pDirtyTail list that has a
+**   clear PGHDR_NEED_SYNC flag or to a page that is older than this one
+**   (so that the right page to eject can be found by following pDirtyPrev
+**   pointers).
+*/
+struct PCache {
+  PgHdr *pDirty, *pDirtyTail;         /* List of dirty pages in LRU order */
+  PgHdr *pSynced;                     /* Last synced page in dirty page list */
+  i64 nRefSum;                        /* Sum of ref counts over all pages */
+  int szCache;                        /* Configured cache size */
+  int szSpill;                        /* Size before spilling occurs */
+  int szPage;                         /* Size of every page in this cache */
+  int szExtra;                        /* Size of extra space for each page */
+  u8 bPurgeable;                      /* True if pages are on backing store */
+  u8 eCreate;                         /* eCreate value for for xFetch() */
+  int (*xStress)(void*,PgHdr*);       /* Call to try make a page clean */
+  void *pStress;                      /* Argument to xStress */
+  sqlite3_pcache *pCache;             /* Pluggable cache module */
+};
+
+/********************************** Test and Debug Logic **********************/
+/*
+** Debug tracing macros.  Enable by by changing the "0" to "1" and
+** recompiling.
+**
+** When sqlite3PcacheTrace is 1, single line trace messages are issued.
+** When sqlite3PcacheTrace is 2, a dump of the pcache showing all cache entries
+** is displayed for many operations, resulting in a lot of output.
+*/
+#if defined(SQLITE_DEBUG) && 0
+  int sqlite3PcacheTrace = 2;       /* 0: off  1: simple  2: cache dumps */
+  int sqlite3PcacheMxDump = 9999;   /* Max cache entries for pcacheDump() */
+# define pcacheTrace(X) if(sqlite3PcacheTrace){sqlite3DebugPrintf X;}
+  static void pcachePageTrace(int i, sqlite3_pcache_page *pLower){
+    PgHdr *pPg;
+    unsigned char *a;
+    int j;
+    if( pLower==0 ){
+      printf("%3d: NULL\n", i);
+    }else{
+      pPg = (PgHdr*)pLower->pExtra;
+      printf("%3d: nRef %2lld flgs %02x data ", i, pPg->nRef, pPg->flags);
+      a = (unsigned char *)pLower->pBuf;
+      for(j=0; j<12; j++) printf("%02x", a[j]);
+      printf(" ptr %p\n", pPg);
+    }
+  }
+  static void pcacheDump(PCache *pCache){
+    int N;
+    int i;
+    sqlite3_pcache_page *pLower;
+
+    if( sqlite3PcacheTrace<2 ) return;
+    if( pCache->pCache==0 ) return;
+    N = sqlite3PcachePagecount(pCache);
+    if( N>sqlite3PcacheMxDump ) N = sqlite3PcacheMxDump;
+    for(i=1; i<=N; i++){
+       pLower = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, i, 0);
+       pcachePageTrace(i, pLower);
+       if( pLower && ((PgHdr*)pLower)->pPage==0 ){
+         sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, pLower, 0);
+       }
+    }
+  }
+#else
+# define pcacheTrace(X)
+# define pcachePageTrace(PGNO, X)
+# define pcacheDump(X)
+#endif
+
+/*
+** Return 1 if pPg is on the dirty list for pCache.  Return 0 if not.
+** This routine runs inside of assert() statements only.
+*/
+#if defined(SQLITE_ENABLE_EXPENSIVE_ASSERT)
+static int pageOnDirtyList(PCache *pCache, PgHdr *pPg){
+  PgHdr *p;
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    if( p==pPg ) return 1;
+  }
+  return 0;
+}
+static int pageNotOnDirtyList(PCache *pCache, PgHdr *pPg){
+  PgHdr *p;
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    if( p==pPg ) return 0;
+  }
+  return 1;
+}
+#else
+# define pageOnDirtyList(A,B)    1
+# define pageNotOnDirtyList(A,B) 1
+#endif
+
+/*
+** Check invariants on a PgHdr entry.  Return true if everything is OK.
+** Return false if any invariant is violated.
+**
+** This routine is for use inside of assert() statements only.  For
+** example:
+**
+**          assert( sqlite3PcachePageSanity(pPg) );
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3PcachePageSanity(PgHdr *pPg){
+  PCache *pCache;
+  assert( pPg!=0 );
+  assert( pPg->pgno>0 || pPg->pPager==0 );    /* Page number is 1 or more */
+  pCache = pPg->pCache;
+  assert( pCache!=0 );      /* Every page has an associated PCache */
+  if( pPg->flags & PGHDR_CLEAN ){
+    assert( (pPg->flags & PGHDR_DIRTY)==0 );/* Cannot be both CLEAN and DIRTY */
+    assert( pageNotOnDirtyList(pCache, pPg) );/* CLEAN pages not on dirtylist */
+  }else{
+    assert( (pPg->flags & PGHDR_DIRTY)!=0 );/* If not CLEAN must be DIRTY */
+    assert( pPg->pDirtyNext==0 || pPg->pDirtyNext->pDirtyPrev==pPg );
+    assert( pPg->pDirtyPrev==0 || pPg->pDirtyPrev->pDirtyNext==pPg );
+    assert( pPg->pDirtyPrev!=0 || pCache->pDirty==pPg );
+    assert( pageOnDirtyList(pCache, pPg) );
+  }
+  /* WRITEABLE pages must also be DIRTY */
+  if( pPg->flags & PGHDR_WRITEABLE ){
+    assert( pPg->flags & PGHDR_DIRTY );     /* WRITEABLE implies DIRTY */
+  }
+  /* NEED_SYNC can be set independently of WRITEABLE.  This can happen,
+  ** for example, when using the sqlite3PagerDontWrite() optimization:
+  **    (1)  Page X is journalled, and gets WRITEABLE and NEED_SEEK.
+  **    (2)  Page X moved to freelist, WRITEABLE is cleared
+  **    (3)  Page X reused, WRITEABLE is set again
+  ** If NEED_SYNC had been cleared in step 2, then it would not be reset
+  ** in step 3, and page might be written into the database without first
+  ** syncing the rollback journal, which might cause corruption on a power
+  ** loss.
+  **
+  ** Another example is when the database page size is smaller than the
+  ** disk sector size.  When any page of a sector is journalled, all pages
+  ** in that sector are marked NEED_SYNC even if they are still CLEAN, just
+  ** in case they are later modified, since all pages in the same sector
+  ** must be journalled and synced before any of those pages can be safely
+  ** written.
+  */
+  return 1;
+}
+#endif /* SQLITE_DEBUG */
+
+
+/********************************** Linked List Management ********************/
+
+/* Allowed values for second argument to pcacheManageDirtyList() */
+#define PCACHE_DIRTYLIST_REMOVE   1    /* Remove pPage from dirty list */
+#define PCACHE_DIRTYLIST_ADD      2    /* Add pPage to the dirty list */
+#define PCACHE_DIRTYLIST_FRONT    3    /* Move pPage to the front of the list */
+
+/*
+** Manage pPage's participation on the dirty list.  Bits of the addRemove
+** argument determines what operation to do.  The 0x01 bit means first
+** remove pPage from the dirty list.  The 0x02 means add pPage back to
+** the dirty list.  Doing both moves pPage to the front of the dirty list.
+*/
+static void pcacheManageDirtyList(PgHdr *pPage, u8 addRemove){
+  PCache *p = pPage->pCache;
+
+  pcacheTrace(("%p.DIRTYLIST.%s %d\n", p,
+                addRemove==1 ? "REMOVE" : addRemove==2 ? "ADD" : "FRONT",
+                pPage->pgno));
+  if( addRemove & PCACHE_DIRTYLIST_REMOVE ){
+    assert( pPage->pDirtyNext || pPage==p->pDirtyTail );
+    assert( pPage->pDirtyPrev || pPage==p->pDirty );
+
+    /* Update the PCache1.pSynced variable if necessary. */
+    if( p->pSynced==pPage ){
+      p->pSynced = pPage->pDirtyPrev;
+    }
+
+    if( pPage->pDirtyNext ){
+      pPage->pDirtyNext->pDirtyPrev = pPage->pDirtyPrev;
+    }else{
+      assert( pPage==p->pDirtyTail );
+      p->pDirtyTail = pPage->pDirtyPrev;
+    }
+    if( pPage->pDirtyPrev ){
+      pPage->pDirtyPrev->pDirtyNext = pPage->pDirtyNext;
+    }else{
+      /* If there are now no dirty pages in the cache, set eCreate to 2.
+      ** This is an optimization that allows sqlite3PcacheFetch() to skip
+      ** searching for a dirty page to eject from the cache when it might
+      ** otherwise have to.  */
+      assert( pPage==p->pDirty );
+      p->pDirty = pPage->pDirtyNext;
+      assert( p->bPurgeable || p->eCreate==2 );
+      if( p->pDirty==0 ){         /*OPTIMIZATION-IF-TRUE*/
+        assert( p->bPurgeable==0 || p->eCreate==1 );
+        p->eCreate = 2;
+      }
+    }
+  }
+  if( addRemove & PCACHE_DIRTYLIST_ADD ){
+    pPage->pDirtyPrev = 0;
+    pPage->pDirtyNext = p->pDirty;
+    if( pPage->pDirtyNext ){
+      assert( pPage->pDirtyNext->pDirtyPrev==0 );
+      pPage->pDirtyNext->pDirtyPrev = pPage;
+    }else{
+      p->pDirtyTail = pPage;
+      if( p->bPurgeable ){
+        assert( p->eCreate==2 );
+        p->eCreate = 1;
+      }
+    }
+    p->pDirty = pPage;
+
+    /* If pSynced is NULL and this page has a clear NEED_SYNC flag, set
+    ** pSynced to point to it. Checking the NEED_SYNC flag is an
+    ** optimization, as if pSynced points to a page with the NEED_SYNC
+    ** flag set sqlite3PcacheFetchStress() searches through all newer
+    ** entries of the dirty-list for a page with NEED_SYNC clear anyway.  */
+    if( !p->pSynced
+     && 0==(pPage->flags&PGHDR_NEED_SYNC)   /*OPTIMIZATION-IF-FALSE*/
+    ){
+      p->pSynced = pPage;
+    }
+  }
+  pcacheDump(p);
+}
+
+/*
+** Wrapper around the pluggable caches xUnpin method. If the cache is
+** being used for an in-memory database, this function is a no-op.
+*/
+static void pcacheUnpin(PgHdr *p){
+  if( p->pCache->bPurgeable ){
+    pcacheTrace(("%p.UNPIN %d\n", p->pCache, p->pgno));
+    sqlite3GlobalConfig.pcache2.xUnpin(p->pCache->pCache, p->pPage, 0);
+    pcacheDump(p->pCache);
+  }
+}
+
+/*
+** Compute the number of pages of cache requested.   p->szCache is the
+** cache size requested by the "PRAGMA cache_size" statement.
+*/
+static int numberOfCachePages(PCache *p){
+  if( p->szCache>=0 ){
+    /* IMPLEMENTATION-OF: R-42059-47211 If the argument N is positive then the
+    ** suggested cache size is set to N. */
+    return p->szCache;
+  }else{
+    i64 n;
+    /* IMPLEMENTATION-OF: R-59858-46238 If the argument N is negative, then the
+    ** number of cache pages is adjusted to be a number of pages that would
+    ** use approximately abs(N*1024) bytes of memory based on the current
+    ** page size. */
+    n = ((-1024*(i64)p->szCache)/(p->szPage+p->szExtra));
+    if( n>1000000000 ) n = 1000000000;
+    return (int)n;
+  }
+}
+
+/*************************************************** General Interfaces ******
+**
+** Initialize and shutdown the page cache subsystem. Neither of these
+** functions are threadsafe.
+*/
+SQLITE_PRIVATE int sqlite3PcacheInitialize(void){
+  if( sqlite3GlobalConfig.pcache2.xInit==0 ){
+    /* IMPLEMENTATION-OF: R-26801-64137 If the xInit() method is NULL, then the
+    ** built-in default page cache is used instead of the application defined
+    ** page cache. */
+    sqlite3PCacheSetDefault();
+    assert( sqlite3GlobalConfig.pcache2.xInit!=0 );
+  }
+  return sqlite3GlobalConfig.pcache2.xInit(sqlite3GlobalConfig.pcache2.pArg);
+}
+SQLITE_PRIVATE void sqlite3PcacheShutdown(void){
+  if( sqlite3GlobalConfig.pcache2.xShutdown ){
+    /* IMPLEMENTATION-OF: R-26000-56589 The xShutdown() method may be NULL. */
+    sqlite3GlobalConfig.pcache2.xShutdown(sqlite3GlobalConfig.pcache2.pArg);
+  }
+}
+
+/*
+** Return the size in bytes of a PCache object.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSize(void){ return sizeof(PCache); }
+
+/*
+** Create a new PCache object. Storage space to hold the object
+** has already been allocated and is passed in as the p pointer.
+** The caller discovers how much space needs to be allocated by
+** calling sqlite3PcacheSize().
+**
+** szExtra is some extra space allocated for each page.  The first
+** 8 bytes of the extra space will be zeroed as the page is allocated,
+** but remaining content will be uninitialized.  Though it is opaque
+** to this module, the extra space really ends up being the MemPage
+** structure in the pager.
+*/
+SQLITE_PRIVATE int sqlite3PcacheOpen(
+  int szPage,                  /* Size of every page */
+  int szExtra,                 /* Extra space associated with each page */
+  int bPurgeable,              /* True if pages are on backing store */
+  int (*xStress)(void*,PgHdr*),/* Call to try to make pages clean */
+  void *pStress,               /* Argument to xStress */
+  PCache *p                    /* Preallocated space for the PCache */
+){
+  memset(p, 0, sizeof(PCache));
+  p->szPage = 1;
+  p->szExtra = szExtra;
+  assert( szExtra>=8 );  /* First 8 bytes will be zeroed */
+  p->bPurgeable = bPurgeable;
+  p->eCreate = 2;
+  p->xStress = xStress;
+  p->pStress = pStress;
+  p->szCache = 100;
+  p->szSpill = 1;
+  pcacheTrace(("%p.OPEN szPage %d bPurgeable %d\n",p,szPage,bPurgeable));
+  return sqlite3PcacheSetPageSize(p, szPage);
+}
+
+/*
+** Change the page size for PCache object. The caller must ensure that there
+** are no outstanding page references when this function is called.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSetPageSize(PCache *pCache, int szPage){
+  assert( pCache->nRefSum==0 && pCache->pDirty==0 );
+  if( pCache->szPage ){
+    sqlite3_pcache *pNew;
+    pNew = sqlite3GlobalConfig.pcache2.xCreate(
+                szPage, pCache->szExtra + ROUND8(sizeof(PgHdr)),
+                pCache->bPurgeable
+    );
+    if( pNew==0 ) return SQLITE_NOMEM_BKPT;
+    sqlite3GlobalConfig.pcache2.xCachesize(pNew, numberOfCachePages(pCache));
+    if( pCache->pCache ){
+      sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
+    }
+    pCache->pCache = pNew;
+    pCache->szPage = szPage;
+    pcacheTrace(("%p.PAGESIZE %d\n",pCache,szPage));
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Try to obtain a page from the cache.
+**
+** This routine returns a pointer to an sqlite3_pcache_page object if
+** such an object is already in cache, or if a new one is created.
+** This routine returns a NULL pointer if the object was not in cache
+** and could not be created.
+**
+** The createFlags should be 0 to check for existing pages and should
+** be 3 (not 1, but 3) to try to create a new page.
+**
+** If the createFlag is 0, then NULL is always returned if the page
+** is not already in the cache.  If createFlag is 1, then a new page
+** is created only if that can be done without spilling dirty pages
+** and without exceeding the cache size limit.
+**
+** The caller needs to invoke sqlite3PcacheFetchFinish() to properly
+** initialize the sqlite3_pcache_page object and convert it into a
+** PgHdr object.  The sqlite3PcacheFetch() and sqlite3PcacheFetchFinish()
+** routines are split this way for performance reasons. When separated
+** they can both (usually) operate without having to push values to
+** the stack on entry and pop them back off on exit, which saves a
+** lot of pushing and popping.
+*/
+SQLITE_PRIVATE sqlite3_pcache_page *sqlite3PcacheFetch(
+  PCache *pCache,       /* Obtain the page from this cache */
+  Pgno pgno,            /* Page number to obtain */
+  int createFlag        /* If true, create page if it does not exist already */
+){
+  int eCreate;
+  sqlite3_pcache_page *pRes;
+
+  assert( pCache!=0 );
+  assert( pCache->pCache!=0 );
+  assert( createFlag==3 || createFlag==0 );
+  assert( pCache->eCreate==((pCache->bPurgeable && pCache->pDirty) ? 1 : 2) );
+
+  /* eCreate defines what to do if the page does not exist.
+  **    0     Do not allocate a new page.  (createFlag==0)
+  **    1     Allocate a new page if doing so is inexpensive.
+  **          (createFlag==1 AND bPurgeable AND pDirty)
+  **    2     Allocate a new page even it doing so is difficult.
+  **          (createFlag==1 AND !(bPurgeable AND pDirty)
+  */
+  eCreate = createFlag & pCache->eCreate;
+  assert( eCreate==0 || eCreate==1 || eCreate==2 );
+  assert( createFlag==0 || pCache->eCreate==eCreate );
+  assert( createFlag==0 || eCreate==1+(!pCache->bPurgeable||!pCache->pDirty) );
+  pRes = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
+  pcacheTrace(("%p.FETCH %d%s (result: %p) ",pCache,pgno,
+               createFlag?" create":"",pRes));
+  pcachePageTrace(pgno, pRes);
+  return pRes;
+}
+
+/*
+** If the sqlite3PcacheFetch() routine is unable to allocate a new
+** page because no clean pages are available for reuse and the cache
+** size limit has been reached, then this routine can be invoked to
+** try harder to allocate a page.  This routine might invoke the stress
+** callback to spill dirty pages to the journal.  It will then try to
+** allocate the new page and will only fail to allocate a new page on
+** an OOM error.
+**
+** This routine should be invoked only after sqlite3PcacheFetch() fails.
+*/
+SQLITE_PRIVATE int sqlite3PcacheFetchStress(
+  PCache *pCache,                 /* Obtain the page from this cache */
+  Pgno pgno,                      /* Page number to obtain */
+  sqlite3_pcache_page **ppPage    /* Write result here */
+){
+  PgHdr *pPg;
+  if( pCache->eCreate==2 ) return 0;
+
+  if( sqlite3PcachePagecount(pCache)>pCache->szSpill ){
+    /* Find a dirty page to write-out and recycle. First try to find a
+    ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC
+    ** cleared), but if that is not possible settle for any other
+    ** unreferenced dirty page.
+    **
+    ** If the LRU page in the dirty list that has a clear PGHDR_NEED_SYNC
+    ** flag is currently referenced, then the following may leave pSynced
+    ** set incorrectly (pointing to other than the LRU page with NEED_SYNC
+    ** cleared). This is Ok, as pSynced is just an optimization.  */
+    for(pPg=pCache->pSynced;
+        pPg && (pPg->nRef || (pPg->flags&PGHDR_NEED_SYNC));
+        pPg=pPg->pDirtyPrev
+    );
+    pCache->pSynced = pPg;
+    if( !pPg ){
+      for(pPg=pCache->pDirtyTail; pPg && pPg->nRef; pPg=pPg->pDirtyPrev);
+    }
+    if( pPg ){
+      int rc;
+#ifdef SQLITE_LOG_CACHE_SPILL
+      sqlite3_log(SQLITE_FULL,
+                  "spill page %d making room for %d - cache used: %d/%d",
+                  pPg->pgno, pgno,
+                  sqlite3GlobalConfig.pcache2.xPagecount(pCache->pCache),
+                numberOfCachePages(pCache));
+#endif
+      pcacheTrace(("%p.SPILL %d\n",pCache,pPg->pgno));
+      rc = pCache->xStress(pCache->pStress, pPg);
+      pcacheDump(pCache);
+      if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
+        return rc;
+      }
+    }
+  }
+  *ppPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, 2);
+  return *ppPage==0 ? SQLITE_NOMEM_BKPT : SQLITE_OK;
+}
+
+/*
+** This is a helper routine for sqlite3PcacheFetchFinish()
+**
+** In the uncommon case where the page being fetched has not been
+** initialized, this routine is invoked to do the initialization.
+** This routine is broken out into a separate function since it
+** requires extra stack manipulation that can be avoided in the common
+** case.
+*/
+static SQLITE_NOINLINE PgHdr *pcacheFetchFinishWithInit(
+  PCache *pCache,             /* Obtain the page from this cache */
+  Pgno pgno,                  /* Page number obtained */
+  sqlite3_pcache_page *pPage  /* Page obtained by prior PcacheFetch() call */
+){
+  PgHdr *pPgHdr;
+  assert( pPage!=0 );
+  pPgHdr = (PgHdr*)pPage->pExtra;
+  assert( pPgHdr->pPage==0 );
+  memset(&pPgHdr->pDirty, 0, sizeof(PgHdr) - offsetof(PgHdr,pDirty));
+  pPgHdr->pPage = pPage;
+  pPgHdr->pData = pPage->pBuf;
+  pPgHdr->pExtra = (void *)&pPgHdr[1];
+  memset(pPgHdr->pExtra, 0, 8);
+  assert( EIGHT_BYTE_ALIGNMENT( pPgHdr->pExtra ) );
+  pPgHdr->pCache = pCache;
+  pPgHdr->pgno = pgno;
+  pPgHdr->flags = PGHDR_CLEAN;
+  return sqlite3PcacheFetchFinish(pCache,pgno,pPage);
+}
+
+/*
+** This routine converts the sqlite3_pcache_page object returned by
+** sqlite3PcacheFetch() into an initialized PgHdr object.  This routine
+** must be called after sqlite3PcacheFetch() in order to get a usable
+** result.
+*/
+SQLITE_PRIVATE PgHdr *sqlite3PcacheFetchFinish(
+  PCache *pCache,             /* Obtain the page from this cache */
+  Pgno pgno,                  /* Page number obtained */
+  sqlite3_pcache_page *pPage  /* Page obtained by prior PcacheFetch() call */
+){
+  PgHdr *pPgHdr;
+
+  assert( pPage!=0 );
+  pPgHdr = (PgHdr *)pPage->pExtra;
+
+  if( !pPgHdr->pPage ){
+    return pcacheFetchFinishWithInit(pCache, pgno, pPage);
+  }
+  pCache->nRefSum++;
+  pPgHdr->nRef++;
+  assert( sqlite3PcachePageSanity(pPgHdr) );
+  return pPgHdr;
+}
+
+/*
+** Decrement the reference count on a page. If the page is clean and the
+** reference count drops to 0, then it is made eligible for recycling.
+*/
+SQLITE_PRIVATE void SQLITE_NOINLINE sqlite3PcacheRelease(PgHdr *p){
+  assert( p->nRef>0 );
+  p->pCache->nRefSum--;
+  if( (--p->nRef)==0 ){
+    if( p->flags&PGHDR_CLEAN ){
+      pcacheUnpin(p);
+    }else{
+      pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT);
+      assert( sqlite3PcachePageSanity(p) );
+    }
+  }
+}
+
+/*
+** Increase the reference count of a supplied page by 1.
+*/
+SQLITE_PRIVATE void sqlite3PcacheRef(PgHdr *p){
+  assert(p->nRef>0);
+  assert( sqlite3PcachePageSanity(p) );
+  p->nRef++;
+  p->pCache->nRefSum++;
+}
+
+/*
+** Drop a page from the cache. There must be exactly one reference to the
+** page. This function deletes that reference, so after it returns the
+** page pointed to by p is invalid.
+*/
+SQLITE_PRIVATE void sqlite3PcacheDrop(PgHdr *p){
+  assert( p->nRef==1 );
+  assert( sqlite3PcachePageSanity(p) );
+  if( p->flags&PGHDR_DIRTY ){
+    pcacheManageDirtyList(p, PCACHE_DIRTYLIST_REMOVE);
+  }
+  p->pCache->nRefSum--;
+  sqlite3GlobalConfig.pcache2.xUnpin(p->pCache->pCache, p->pPage, 1);
+}
+
+/*
+** Make sure the page is marked as dirty. If it isn't dirty already,
+** make it so.
+*/
+SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr *p){
+  assert( p->nRef>0 );
+  assert( sqlite3PcachePageSanity(p) );
+  if( p->flags & (PGHDR_CLEAN|PGHDR_DONT_WRITE) ){    /*OPTIMIZATION-IF-FALSE*/
+    p->flags &= ~PGHDR_DONT_WRITE;
+    if( p->flags & PGHDR_CLEAN ){
+      p->flags ^= (PGHDR_DIRTY|PGHDR_CLEAN);
+      pcacheTrace(("%p.DIRTY %d\n",p->pCache,p->pgno));
+      assert( (p->flags & (PGHDR_DIRTY|PGHDR_CLEAN))==PGHDR_DIRTY );
+      pcacheManageDirtyList(p, PCACHE_DIRTYLIST_ADD);
+      assert( sqlite3PcachePageSanity(p) );
+    }
+    assert( sqlite3PcachePageSanity(p) );
+  }
+}
+
+/*
+** Make sure the page is marked as clean. If it isn't clean already,
+** make it so.
+*/
+SQLITE_PRIVATE void sqlite3PcacheMakeClean(PgHdr *p){
+  assert( sqlite3PcachePageSanity(p) );
+  assert( (p->flags & PGHDR_DIRTY)!=0 );
+  assert( (p->flags & PGHDR_CLEAN)==0 );
+  pcacheManageDirtyList(p, PCACHE_DIRTYLIST_REMOVE);
+  p->flags &= ~(PGHDR_DIRTY|PGHDR_NEED_SYNC|PGHDR_WRITEABLE);
+  p->flags |= PGHDR_CLEAN;
+  pcacheTrace(("%p.CLEAN %d\n",p->pCache,p->pgno));
+  assert( sqlite3PcachePageSanity(p) );
+  if( p->nRef==0 ){
+    pcacheUnpin(p);
+  }
+}
+
+/*
+** Make every page in the cache clean.
+*/
+SQLITE_PRIVATE void sqlite3PcacheCleanAll(PCache *pCache){
+  PgHdr *p;
+  pcacheTrace(("%p.CLEAN-ALL\n",pCache));
+  while( (p = pCache->pDirty)!=0 ){
+    sqlite3PcacheMakeClean(p);
+  }
+}
+
+/*
+** Clear the PGHDR_NEED_SYNC and PGHDR_WRITEABLE flag from all dirty pages.
+*/
+SQLITE_PRIVATE void sqlite3PcacheClearWritable(PCache *pCache){
+  PgHdr *p;
+  pcacheTrace(("%p.CLEAR-WRITEABLE\n",pCache));
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    p->flags &= ~(PGHDR_NEED_SYNC|PGHDR_WRITEABLE);
+  }
+  pCache->pSynced = pCache->pDirtyTail;
+}
+
+/*
+** Clear the PGHDR_NEED_SYNC flag from all dirty pages.
+*/
+SQLITE_PRIVATE void sqlite3PcacheClearSyncFlags(PCache *pCache){
+  PgHdr *p;
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    p->flags &= ~PGHDR_NEED_SYNC;
+  }
+  pCache->pSynced = pCache->pDirtyTail;
+}
+
+/*
+** Change the page number of page p to newPgno.
+*/
+SQLITE_PRIVATE void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
+  PCache *pCache = p->pCache;
+  sqlite3_pcache_page *pOther;
+  assert( p->nRef>0 );
+  assert( newPgno>0 );
+  assert( sqlite3PcachePageSanity(p) );
+  pcacheTrace(("%p.MOVE %d -> %d\n",pCache,p->pgno,newPgno));
+  pOther = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, newPgno, 0);
+  if( pOther ){
+    PgHdr *pXPage = (PgHdr*)pOther->pExtra;
+    assert( pXPage->nRef==0 );
+    pXPage->nRef++;
+    pCache->nRefSum++;
+    sqlite3PcacheDrop(pXPage);
+  }
+  sqlite3GlobalConfig.pcache2.xRekey(pCache->pCache, p->pPage, p->pgno,newPgno);
+  p->pgno = newPgno;
+  if( (p->flags&PGHDR_DIRTY) && (p->flags&PGHDR_NEED_SYNC) ){
+    pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT);
+    assert( sqlite3PcachePageSanity(p) );
+  }
+}
+
+/*
+** Drop every cache entry whose page number is greater than "pgno". The
+** caller must ensure that there are no outstanding references to any pages
+** other than page 1 with a page number greater than pgno.
+**
+** If there is a reference to page 1 and the pgno parameter passed to this
+** function is 0, then the data area associated with page 1 is zeroed, but
+** the page object is not dropped.
+*/
+SQLITE_PRIVATE void sqlite3PcacheTruncate(PCache *pCache, Pgno pgno){
+  if( pCache->pCache ){
+    PgHdr *p;
+    PgHdr *pNext;
+    pcacheTrace(("%p.TRUNCATE %d\n",pCache,pgno));
+    for(p=pCache->pDirty; p; p=pNext){
+      pNext = p->pDirtyNext;
+      /* This routine never gets call with a positive pgno except right
+      ** after sqlite3PcacheCleanAll().  So if there are dirty pages,
+      ** it must be that pgno==0.
+      */
+      assert( p->pgno>0 );
+      if( p->pgno>pgno ){
+        assert( p->flags&PGHDR_DIRTY );
+        sqlite3PcacheMakeClean(p);
+      }
+    }
+    if( pgno==0 && pCache->nRefSum ){
+      sqlite3_pcache_page *pPage1;
+      pPage1 = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache,1,0);
+      if( ALWAYS(pPage1) ){  /* Page 1 is always available in cache, because
+                             ** pCache->nRefSum>0 */
+        memset(pPage1->pBuf, 0, pCache->szPage);
+        pgno = 1;
+      }
+    }
+    sqlite3GlobalConfig.pcache2.xTruncate(pCache->pCache, pgno+1);
+  }
+}
+
+/*
+** Close a cache.
+*/
+SQLITE_PRIVATE void sqlite3PcacheClose(PCache *pCache){
+  assert( pCache->pCache!=0 );
+  pcacheTrace(("%p.CLOSE\n",pCache));
+  sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
+}
+
+/*
+** Discard the contents of the cache.
+*/
+SQLITE_PRIVATE void sqlite3PcacheClear(PCache *pCache){
+  sqlite3PcacheTruncate(pCache, 0);
+}
+
+/*
+** Merge two lists of pages connected by pDirty and in pgno order.
+** Do not bother fixing the pDirtyPrev pointers.
+*/
+static PgHdr *pcacheMergeDirtyList(PgHdr *pA, PgHdr *pB){
+  PgHdr result, *pTail;
+  pTail = &result;
+  assert( pA!=0 && pB!=0 );
+  for(;;){
+    if( pA->pgno<pB->pgno ){
+      pTail->pDirty = pA;
+      pTail = pA;
+      pA = pA->pDirty;
+      if( pA==0 ){
+        pTail->pDirty = pB;
+        break;
+      }
+    }else{
+      pTail->pDirty = pB;
+      pTail = pB;
+      pB = pB->pDirty;
+      if( pB==0 ){
+        pTail->pDirty = pA;
+        break;
+      }
+    }
+  }
+  return result.pDirty;
+}
+
+/*
+** Sort the list of pages in ascending order by pgno.  Pages are
+** connected by pDirty pointers.  The pDirtyPrev pointers are
+** corrupted by this sort.
+**
+** Since there cannot be more than 2^31 distinct pages in a database,
+** there cannot be more than 31 buckets required by the merge sorter.
+** One extra bucket is added to catch overflow in case something
+** ever changes to make the previous sentence incorrect.
+*/
+#define N_SORT_BUCKET  32
+static PgHdr *pcacheSortDirtyList(PgHdr *pIn){
+  PgHdr *a[N_SORT_BUCKET], *p;
+  int i;
+  memset(a, 0, sizeof(a));
+  while( pIn ){
+    p = pIn;
+    pIn = p->pDirty;
+    p->pDirty = 0;
+    for(i=0; ALWAYS(i<N_SORT_BUCKET-1); i++){
+      if( a[i]==0 ){
+        a[i] = p;
+        break;
+      }else{
+        p = pcacheMergeDirtyList(a[i], p);
+        a[i] = 0;
+      }
+    }
+    if( NEVER(i==N_SORT_BUCKET-1) ){
+      /* To get here, there need to be 2^(N_SORT_BUCKET) elements in
+      ** the input list.  But that is impossible.
+      */
+      a[i] = pcacheMergeDirtyList(a[i], p);
+    }
+  }
+  p = a[0];
+  for(i=1; i<N_SORT_BUCKET; i++){
+    if( a[i]==0 ) continue;
+    p = p ? pcacheMergeDirtyList(p, a[i]) : a[i];
+  }
+  return p;
+}
+
+/*
+** Return a list of all dirty pages in the cache, sorted by page number.
+*/
+SQLITE_PRIVATE PgHdr *sqlite3PcacheDirtyList(PCache *pCache){
+  PgHdr *p;
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    p->pDirty = p->pDirtyNext;
+  }
+  return pcacheSortDirtyList(pCache->pDirty);
+}
+
+/*
+** Return the total number of references to all pages held by the cache.
+**
+** This is not the total number of pages referenced, but the sum of the
+** reference count for all pages.
+*/
+SQLITE_PRIVATE i64 sqlite3PcacheRefCount(PCache *pCache){
+  return pCache->nRefSum;
+}
+
+/*
+** Return the number of references to the page supplied as an argument.
+*/
+SQLITE_PRIVATE i64 sqlite3PcachePageRefcount(PgHdr *p){
+  return p->nRef;
+}
+
+/*
+** Return the total number of pages in the cache.
+*/
+SQLITE_PRIVATE int sqlite3PcachePagecount(PCache *pCache){
+  assert( pCache->pCache!=0 );
+  return sqlite3GlobalConfig.pcache2.xPagecount(pCache->pCache);
+}
+
+#ifdef SQLITE_TEST
+/*
+** Get the suggested cache-size value.
+*/
+SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *pCache){
+  return numberOfCachePages(pCache);
+}
+#endif
+
+/*
+** Set the suggested cache-size value.
+*/
+SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *pCache, int mxPage){
+  assert( pCache->pCache!=0 );
+  pCache->szCache = mxPage;
+  sqlite3GlobalConfig.pcache2.xCachesize(pCache->pCache,
+                                         numberOfCachePages(pCache));
+}
+
+/*
+** Set the suggested cache-spill value.  Make no changes if if the
+** argument is zero.  Return the effective cache-spill size, which will
+** be the larger of the szSpill and szCache.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSetSpillsize(PCache *p, int mxPage){
+  int res;
+  assert( p->pCache!=0 );
+  if( mxPage ){
+    if( mxPage<0 ){
+      mxPage = (int)((-1024*(i64)mxPage)/(p->szPage+p->szExtra));
+    }
+    p->szSpill = mxPage;
+  }
+  res = numberOfCachePages(p);
+  if( res<p->szSpill ) res = p->szSpill;
+  return res;
+}
+
+/*
+** Free up as much memory as possible from the page cache.
+*/
+SQLITE_PRIVATE void sqlite3PcacheShrink(PCache *pCache){
+  assert( pCache->pCache!=0 );
+  sqlite3GlobalConfig.pcache2.xShrink(pCache->pCache);
+}
+
+/*
+** Return the size of the header added by this middleware layer
+** in the page-cache hierarchy.
+*/
+SQLITE_PRIVATE int sqlite3HeaderSizePcache(void){ return ROUND8(sizeof(PgHdr)); }
+
+/*
+** Return the number of dirty pages currently in the cache, as a percentage
+** of the configured cache size.
+*/
+SQLITE_PRIVATE int sqlite3PCachePercentDirty(PCache *pCache){
+  PgHdr *pDirty;
+  int nDirty = 0;
+  int nCache = numberOfCachePages(pCache);
+  for(pDirty=pCache->pDirty; pDirty; pDirty=pDirty->pDirtyNext) nDirty++;
+  return nCache ? (int)(((i64)nDirty * 100) / nCache) : 0;
+}
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+/*
+** Return true if there are one or more dirty pages in the cache. Else false.
+*/
+SQLITE_PRIVATE int sqlite3PCacheIsDirty(PCache *pCache){
+  return (pCache->pDirty!=0);
+}
+#endif
+
+#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
+/*
+** For all dirty pages currently in the cache, invoke the specified
+** callback. This is only used if the SQLITE_CHECK_PAGES macro is
+** defined.
+*/
+SQLITE_PRIVATE void sqlite3PcacheIterateDirty(PCache *pCache, void (*xIter)(PgHdr *)){
+  PgHdr *pDirty;
+  for(pDirty=pCache->pDirty; pDirty; pDirty=pDirty->pDirtyNext){
+    xIter(pDirty);
+  }
+}
+#endif
+
+/************** End of pcache.c **********************************************/
+/************** Begin file pcache1.c *****************************************/
+/*
+** 2008 November 05
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements the default page cache implementation (the
+** sqlite3_pcache interface). It also contains part of the implementation
+** of the SQLITE_CONFIG_PAGECACHE and sqlite3_release_memory() features.
+** If the default page cache implementation is overridden, then neither of
+** these two features are available.
+**
+** A Page cache line looks like this:
+**
+**  -------------------------------------------------------------
+**  |  database page content   |  PgHdr1  |  MemPage  |  PgHdr  |
+**  -------------------------------------------------------------
+**
+** The database page content is up front (so that buffer overreads tend to
+** flow harmlessly into the PgHdr1, MemPage, and PgHdr extensions).   MemPage
+** is the extension added by the btree.c module containing information such
+** as the database page number and how that database page is used.  PgHdr
+** is added by the pcache.c layer and contains information used to keep track
+** of which pages are "dirty".  PgHdr1 is an extension added by this
+** module (pcache1.c).  The PgHdr1 header is a subclass of sqlite3_pcache_page.
+** PgHdr1 contains information needed to look up a page by its page number.
+** The superclass sqlite3_pcache_page.pBuf points to the start of the
+** database page content and sqlite3_pcache_page.pExtra points to PgHdr.
+**
+** The size of the extension (MemPage+PgHdr+PgHdr1) can be determined at
+** runtime using sqlite3_config(SQLITE_CONFIG_PCACHE_HDRSZ, &size).  The
+** sizes of the extensions sum to 272 bytes on x64 for 3.8.10, but this
+** size can vary according to architecture, compile-time options, and
+** SQLite library version number.
+**
+** Historical note:  It used to be that if the SQLITE_PCACHE_SEPARATE_HEADER
+** was defined, then the page content would be held in a separate memory
+** allocation from the PgHdr1.  This was intended to avoid clownshoe memory
+** allocations.  However, the btree layer needs a small (16-byte) overrun
+** area after the page content buffer.  The header serves as that overrun
+** area.  Therefore SQLITE_PCACHE_SEPARATE_HEADER was discontinued to avoid
+** any possibility of a memory error.
+**
+** This module tracks pointers to PgHdr1 objects.  Only pcache.c communicates
+** with this module.  Information is passed back and forth as PgHdr1 pointers.
+**
+** The pcache.c and pager.c modules deal pointers to PgHdr objects.
+** The btree.c module deals with pointers to MemPage objects.
+**
+** SOURCE OF PAGE CACHE MEMORY:
+**
+** Memory for a page might come from any of three sources:
+**
+**    (1)  The general-purpose memory allocator - sqlite3Malloc()
+**    (2)  Global page-cache memory provided using sqlite3_config() with
+**         SQLITE_CONFIG_PAGECACHE.
+**    (3)  PCache-local bulk allocation.
+**
+** The third case is a chunk of heap memory (defaulting to 100 pages worth)
+** that is allocated when the page cache is created.  The size of the local
+** bulk allocation can be adjusted using
+**
+**     sqlite3_config(SQLITE_CONFIG_PAGECACHE, (void*)0, 0, N).
+**
+** If N is positive, then N pages worth of memory are allocated using a single
+** sqlite3Malloc() call and that memory is used for the first N pages allocated.
+** Or if N is negative, then -1024*N bytes of memory are allocated and used
+** for as many pages as can be accommodated.
+**
+** Only one of (2) or (3) can be used.  Once the memory available to (2) or
+** (3) is exhausted, subsequent allocations fail over to the general-purpose
+** memory allocator (1).
+**
+** Earlier versions of SQLite used only methods (1) and (2).  But experiments
+** show that method (3) with N==100 provides about a 5% performance boost for
+** common workloads.
+*/
+/* #include "sqliteInt.h" */
+
+typedef struct PCache1 PCache1;
+typedef struct PgHdr1 PgHdr1;
+typedef struct PgFreeslot PgFreeslot;
+typedef struct PGroup PGroup;
+
+/*
+** Each cache entry is represented by an instance of the following
+** structure. A buffer of PgHdr1.pCache->szPage bytes is allocated
+** directly before this structure and is used to cache the page content.
+**
+** When reading a corrupt database file, it is possible that SQLite might
+** read a few bytes (no more than 16 bytes) past the end of the page buffer.
+** It will only read past the end of the page buffer, never write.  This
+** object is positioned immediately after the page buffer to serve as an
+** overrun area, so that overreads are harmless.
+**
+** Variables isBulkLocal and isAnchor were once type "u8". That works,
+** but causes a 2-byte gap in the structure for most architectures (since
+** pointers must be either 4 or 8-byte aligned). As this structure is located
+** in memory directly after the associated page data, if the database is
+** corrupt, code at the b-tree layer may overread the page buffer and
+** read part of this structure before the corruption is detected. This
+** can cause a valgrind error if the uninitialized gap is accessed. Using u16
+** ensures there is no such gap, and therefore no bytes of uninitialized
+** memory in the structure.
+**
+** The pLruNext and pLruPrev pointers form a double-linked circular list
+** of all pages that are unpinned.  The PGroup.lru element (which should be
+** the only element on the list with PgHdr1.isAnchor set to 1) forms the
+** beginning and the end of the list.
+*/
+struct PgHdr1 {
+  sqlite3_pcache_page page; /* Base class. Must be first. pBuf & pExtra */
+  unsigned int iKey;        /* Key value (page number) */
+  u16 isBulkLocal;          /* This page from bulk local storage */
+  u16 isAnchor;             /* This is the PGroup.lru element */
+  PgHdr1 *pNext;            /* Next in hash table chain */
+  PCache1 *pCache;          /* Cache that currently owns this page */
+  PgHdr1 *pLruNext;         /* Next in circular LRU list of unpinned pages */
+  PgHdr1 *pLruPrev;         /* Previous in LRU list of unpinned pages */
+                            /* NB: pLruPrev is only valid if pLruNext!=0 */
+};
+
+/*
+** A page is pinned if it is not on the LRU list.  To be "pinned" means
+** that the page is in active use and must not be deallocated.
+*/
+#define PAGE_IS_PINNED(p)    ((p)->pLruNext==0)
+#define PAGE_IS_UNPINNED(p)  ((p)->pLruNext!=0)
+
+/* Each page cache (or PCache) belongs to a PGroup.  A PGroup is a set
+** of one or more PCaches that are able to recycle each other's unpinned
+** pages when they are under memory pressure.  A PGroup is an instance of
+** the following object.
+**
+** This page cache implementation works in one of two modes:
+**
+**   (1)  Every PCache is the sole member of its own PGroup.  There is
+**        one PGroup per PCache.
+**
+**   (2)  There is a single global PGroup that all PCaches are a member
+**        of.
+**
+** Mode 1 uses more memory (since PCache instances are not able to rob
+** unused pages from other PCaches) but it also operates without a mutex,
+** and is therefore often faster.  Mode 2 requires a mutex in order to be
+** threadsafe, but recycles pages more efficiently.
+**
+** For mode (1), PGroup.mutex is NULL.  For mode (2) there is only a single
+** PGroup which is the pcache1.grp global variable and its mutex is
+** SQLITE_MUTEX_STATIC_LRU.
+*/
+struct PGroup {
+  sqlite3_mutex *mutex;          /* MUTEX_STATIC_LRU or NULL */
+  unsigned int nMaxPage;         /* Sum of nMax for purgeable caches */
+  unsigned int nMinPage;         /* Sum of nMin for purgeable caches */
+  unsigned int mxPinned;         /* nMaxpage + 10 - nMinPage */
+  unsigned int nPurgeable;       /* Number of purgeable pages allocated */
+  PgHdr1 lru;                    /* The beginning and end of the LRU list */
+};
+
+/* Each page cache is an instance of the following object.  Every
+** open database file (including each in-memory database and each
+** temporary or transient database) has a single page cache which
+** is an instance of this object.
+**
+** Pointers to structures of this type are cast and returned as
+** opaque sqlite3_pcache* handles.
+*/
+struct PCache1 {
+  /* Cache configuration parameters. Page size (szPage) and the purgeable
+  ** flag (bPurgeable) and the pnPurgeable pointer are all set when the
+  ** cache is created and are never changed thereafter. nMax may be
+  ** modified at any time by a call to the pcache1Cachesize() method.
+  ** The PGroup mutex must be held when accessing nMax.
+  */
+  PGroup *pGroup;                     /* PGroup this cache belongs to */
+  unsigned int *pnPurgeable;          /* Pointer to pGroup->nPurgeable */
+  int szPage;                         /* Size of database content section */
+  int szExtra;                        /* sizeof(MemPage)+sizeof(PgHdr) */
+  int szAlloc;                        /* Total size of one pcache line */
+  int bPurgeable;                     /* True if cache is purgeable */
+  unsigned int nMin;                  /* Minimum number of pages reserved */
+  unsigned int nMax;                  /* Configured "cache_size" value */
+  unsigned int n90pct;                /* nMax*9/10 */
+  unsigned int iMaxKey;               /* Largest key seen since xTruncate() */
+  unsigned int nPurgeableDummy;       /* pnPurgeable points here when not used*/
+
+  /* Hash table of all pages. The following variables may only be accessed
+  ** when the accessor is holding the PGroup mutex.
+  */
+  unsigned int nRecyclable;           /* Number of pages in the LRU list */
+  unsigned int nPage;                 /* Total number of pages in apHash */
+  unsigned int nHash;                 /* Number of slots in apHash[] */
+  PgHdr1 **apHash;                    /* Hash table for fast lookup by key */
+  PgHdr1 *pFree;                      /* List of unused pcache-local pages */
+  void *pBulk;                        /* Bulk memory used by pcache-local */
+};
+
+/*
+** Free slots in the allocator used to divide up the global page cache
+** buffer provided using the SQLITE_CONFIG_PAGECACHE mechanism.
+*/
+struct PgFreeslot {
+  PgFreeslot *pNext;  /* Next free slot */
+};
+
+/*
+** Global data used by this cache.
+*/
+static SQLITE_WSD struct PCacheGlobal {
+  PGroup grp;                    /* The global PGroup for mode (2) */
+
+  /* Variables related to SQLITE_CONFIG_PAGECACHE settings.  The
+  ** szSlot, nSlot, pStart, pEnd, nReserve, and isInit values are all
+  ** fixed at sqlite3_initialize() time and do not require mutex protection.
+  ** The nFreeSlot and pFree values do require mutex protection.
+  */
+  int isInit;                    /* True if initialized */
+  int separateCache;             /* Use a new PGroup for each PCache */
+  int nInitPage;                 /* Initial bulk allocation size */
+  int szSlot;                    /* Size of each free slot */
+  int nSlot;                     /* The number of pcache slots */
+  int nReserve;                  /* Try to keep nFreeSlot above this */
+  void *pStart, *pEnd;           /* Bounds of global page cache memory */
+  /* Above requires no mutex.  Use mutex below for variable that follow. */
+  sqlite3_mutex *mutex;          /* Mutex for accessing the following: */
+  PgFreeslot *pFree;             /* Free page blocks */
+  int nFreeSlot;                 /* Number of unused pcache slots */
+  /* The following value requires a mutex to change.  We skip the mutex on
+  ** reading because (1) most platforms read a 32-bit integer atomically and
+  ** (2) even if an incorrect value is read, no great harm is done since this
+  ** is really just an optimization. */
+  int bUnderPressure;            /* True if low on PAGECACHE memory */
+} pcache1_g;
+
+/*
+** All code in this file should access the global structure above via the
+** alias "pcache1". This ensures that the WSD emulation is used when
+** compiling for systems that do not support real WSD.
+*/
+#define pcache1 (GLOBAL(struct PCacheGlobal, pcache1_g))
+
+/*
+** Macros to enter and leave the PCache LRU mutex.
+*/
+#if !defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) || SQLITE_THREADSAFE==0
+# define pcache1EnterMutex(X)  assert((X)->mutex==0)
+# define pcache1LeaveMutex(X)  assert((X)->mutex==0)
+# define PCACHE1_MIGHT_USE_GROUP_MUTEX 0
+#else
+# define pcache1EnterMutex(X) sqlite3_mutex_enter((X)->mutex)
+# define pcache1LeaveMutex(X) sqlite3_mutex_leave((X)->mutex)
+# define PCACHE1_MIGHT_USE_GROUP_MUTEX 1
+#endif
+
+/******************************************************************************/
+/******** Page Allocation/SQLITE_CONFIG_PCACHE Related Functions **************/
+
+
+/*
+** This function is called during initialization if a static buffer is
+** supplied to use for the page-cache by passing the SQLITE_CONFIG_PAGECACHE
+** verb to sqlite3_config(). Parameter pBuf points to an allocation large
+** enough to contain 'n' buffers of 'sz' bytes each.
+**
+** This routine is called from sqlite3_initialize() and so it is guaranteed
+** to be serialized already.  There is no need for further mutexing.
+*/
+SQLITE_PRIVATE void sqlite3PCacheBufferSetup(void *pBuf, int sz, int n){
+  if( pcache1.isInit ){
+    PgFreeslot *p;
+    if( pBuf==0 ) sz = n = 0;
+    if( n==0 ) sz = 0;
+    sz = ROUNDDOWN8(sz);
+    pcache1.szSlot = sz;
+    pcache1.nSlot = pcache1.nFreeSlot = n;
+    pcache1.nReserve = n>90 ? 10 : (n/10 + 1);
+    pcache1.pStart = pBuf;
+    pcache1.pFree = 0;
+    pcache1.bUnderPressure = 0;
+    while( n-- ){
+      p = (PgFreeslot*)pBuf;
+      p->pNext = pcache1.pFree;
+      pcache1.pFree = p;
+      pBuf = (void*)&((char*)pBuf)[sz];
+    }
+    pcache1.pEnd = pBuf;
+  }
+}
+
+/*
+** Try to initialize the pCache->pFree and pCache->pBulk fields.  Return
+** true if pCache->pFree ends up containing one or more free pages.
+*/
+static int pcache1InitBulk(PCache1 *pCache){
+  i64 szBulk;
+  char *zBulk;
+  if( pcache1.nInitPage==0 ) return 0;
+  /* Do not bother with a bulk allocation if the cache size very small */
+  if( pCache->nMax<3 ) return 0;
+  sqlite3BeginBenignMalloc();
+  if( pcache1.nInitPage>0 ){
+    szBulk = pCache->szAlloc * (i64)pcache1.nInitPage;
+  }else{
+    szBulk = -1024 * (i64)pcache1.nInitPage;
+  }
+  if( szBulk > pCache->szAlloc*(i64)pCache->nMax ){
+    szBulk = pCache->szAlloc*(i64)pCache->nMax;
+  }
+  zBulk = pCache->pBulk = sqlite3Malloc( szBulk );
+  sqlite3EndBenignMalloc();
+  if( zBulk ){
+    int nBulk = sqlite3MallocSize(zBulk)/pCache->szAlloc;
+    do{
+      PgHdr1 *pX = (PgHdr1*)&zBulk[pCache->szPage];
+      pX->page.pBuf = zBulk;
+      pX->page.pExtra = (u8*)pX + ROUND8(sizeof(*pX));
+      assert( EIGHT_BYTE_ALIGNMENT( pX->page.pExtra ) );
+      pX->isBulkLocal = 1;
+      pX->isAnchor = 0;
+      pX->pNext = pCache->pFree;
+      pX->pLruPrev = 0;           /* Initializing this saves a valgrind error */
+      pCache->pFree = pX;
+      zBulk += pCache->szAlloc;
+    }while( --nBulk );
+  }
+  return pCache->pFree!=0;
+}
+
+/*
+** Malloc function used within this file to allocate space from the buffer
+** configured using sqlite3_config(SQLITE_CONFIG_PAGECACHE) option. If no
+** such buffer exists or there is no space left in it, this function falls
+** back to sqlite3Malloc().
+**
+** Multiple threads can run this routine at the same time.  Global variables
+** in pcache1 need to be protected via mutex.
+*/
+static void *pcache1Alloc(int nByte){
+  void *p = 0;
+  assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
+  if( nByte<=pcache1.szSlot ){
+    sqlite3_mutex_enter(pcache1.mutex);
+    p = (PgHdr1 *)pcache1.pFree;
+    if( p ){
+      pcache1.pFree = pcache1.pFree->pNext;
+      pcache1.nFreeSlot--;
+      pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve;
+      assert( pcache1.nFreeSlot>=0 );
+      sqlite3StatusHighwater(SQLITE_STATUS_PAGECACHE_SIZE, nByte);
+      sqlite3StatusUp(SQLITE_STATUS_PAGECACHE_USED, 1);
+    }
+    sqlite3_mutex_leave(pcache1.mutex);
+  }
+  if( p==0 ){
+    /* Memory is not available in the SQLITE_CONFIG_PAGECACHE pool.  Get
+    ** it from sqlite3Malloc instead.
+    */
+    p = sqlite3Malloc(nByte);
+#ifndef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
+    if( p ){
+      int sz = sqlite3MallocSize(p);
+      sqlite3_mutex_enter(pcache1.mutex);
+      sqlite3StatusHighwater(SQLITE_STATUS_PAGECACHE_SIZE, nByte);
+      sqlite3StatusUp(SQLITE_STATUS_PAGECACHE_OVERFLOW, sz);
+      sqlite3_mutex_leave(pcache1.mutex);
+    }
+#endif
+    sqlite3MemdebugSetType(p, MEMTYPE_PCACHE);
+  }
+  return p;
+}
+
+/*
+** Free an allocated buffer obtained from pcache1Alloc().
+*/
+static void pcache1Free(void *p){
+  if( p==0 ) return;
+  if( SQLITE_WITHIN(p, pcache1.pStart, pcache1.pEnd) ){
+    PgFreeslot *pSlot;
+    sqlite3_mutex_enter(pcache1.mutex);
+    sqlite3StatusDown(SQLITE_STATUS_PAGECACHE_USED, 1);
+    pSlot = (PgFreeslot*)p;
+    pSlot->pNext = pcache1.pFree;
+    pcache1.pFree = pSlot;
+    pcache1.nFreeSlot++;
+    pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve;
+    assert( pcache1.nFreeSlot<=pcache1.nSlot );
+    sqlite3_mutex_leave(pcache1.mutex);
+  }else{
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
+    sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+#ifndef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
+    {
+      int nFreed = 0;
+      nFreed = sqlite3MallocSize(p);
+      sqlite3_mutex_enter(pcache1.mutex);
+      sqlite3StatusDown(SQLITE_STATUS_PAGECACHE_OVERFLOW, nFreed);
+      sqlite3_mutex_leave(pcache1.mutex);
+    }
+#endif
+    sqlite3_free(p);
+  }
+}
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/*
+** Return the size of a pcache allocation
+*/
+static int pcache1MemSize(void *p){
+  if( p>=pcache1.pStart && p<pcache1.pEnd ){
+    return pcache1.szSlot;
+  }else{
+    int iSize;
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
+    sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+    iSize = sqlite3MallocSize(p);
+    sqlite3MemdebugSetType(p, MEMTYPE_PCACHE);
+    return iSize;
+  }
+}
+#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */
+
+/*
+** Allocate a new page object initially associated with cache pCache.
+*/
+static PgHdr1 *pcache1AllocPage(PCache1 *pCache, int benignMalloc){
+  PgHdr1 *p = 0;
+  void *pPg;
+
+  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
+  if( pCache->pFree || (pCache->nPage==0 && pcache1InitBulk(pCache)) ){
+    assert( pCache->pFree!=0 );
+    p = pCache->pFree;
+    pCache->pFree = p->pNext;
+    p->pNext = 0;
+  }else{
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+    /* The group mutex must be released before pcache1Alloc() is called. This
+    ** is because it might call sqlite3_release_memory(), which assumes that
+    ** this mutex is not held. */
+    assert( pcache1.separateCache==0 );
+    assert( pCache->pGroup==&pcache1.grp );
+    pcache1LeaveMutex(pCache->pGroup);
+#endif
+    if( benignMalloc ){ sqlite3BeginBenignMalloc(); }
+    pPg = pcache1Alloc(pCache->szAlloc);
+    if( benignMalloc ){ sqlite3EndBenignMalloc(); }
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+    pcache1EnterMutex(pCache->pGroup);
+#endif
+    if( pPg==0 ) return 0;
+    p = (PgHdr1 *)&((u8 *)pPg)[pCache->szPage];
+    p->page.pBuf = pPg;
+    p->page.pExtra = (u8*)p + ROUND8(sizeof(*p));
+    assert( EIGHT_BYTE_ALIGNMENT( p->page.pExtra ) );
+    p->isBulkLocal = 0;
+    p->isAnchor = 0;
+    p->pLruPrev = 0;           /* Initializing this saves a valgrind error */
+  }
+  (*pCache->pnPurgeable)++;
+  return p;
+}
+
+/*
+** Free a page object allocated by pcache1AllocPage().
+*/
+static void pcache1FreePage(PgHdr1 *p){
+  PCache1 *pCache;
+  assert( p!=0 );
+  pCache = p->pCache;
+  assert( sqlite3_mutex_held(p->pCache->pGroup->mutex) );
+  if( p->isBulkLocal ){
+    p->pNext = pCache->pFree;
+    pCache->pFree = p;
+  }else{
+    pcache1Free(p->page.pBuf);
+  }
+  (*pCache->pnPurgeable)--;
+}
+
+/*
+** Malloc function used by SQLite to obtain space from the buffer configured
+** using sqlite3_config(SQLITE_CONFIG_PAGECACHE) option. If no such buffer
+** exists, this function falls back to sqlite3Malloc().
+*/
+SQLITE_PRIVATE void *sqlite3PageMalloc(int sz){
+  assert( sz<=65536+8 ); /* These allocations are never very large */
+  return pcache1Alloc(sz);
+}
+
+/*
+** Free an allocated buffer obtained from sqlite3PageMalloc().
+*/
+SQLITE_PRIVATE void sqlite3PageFree(void *p){
+  pcache1Free(p);
+}
+
+
+/*
+** Return true if it desirable to avoid allocating a new page cache
+** entry.
+**
+** If memory was allocated specifically to the page cache using
+** SQLITE_CONFIG_PAGECACHE but that memory has all been used, then
+** it is desirable to avoid allocating a new page cache entry because
+** presumably SQLITE_CONFIG_PAGECACHE was suppose to be sufficient
+** for all page cache needs and we should not need to spill the
+** allocation onto the heap.
+**
+** Or, the heap is used for all page cache memory but the heap is
+** under memory pressure, then again it is desirable to avoid
+** allocating a new page cache entry in order to avoid stressing
+** the heap even further.
+*/
+static int pcache1UnderMemoryPressure(PCache1 *pCache){
+  if( pcache1.nSlot && (pCache->szPage+pCache->szExtra)<=pcache1.szSlot ){
+    return pcache1.bUnderPressure;
+  }else{
+    return sqlite3HeapNearlyFull();
+  }
+}
+
+/******************************************************************************/
+/******** General Implementation Functions ************************************/
+
+/*
+** This function is used to resize the hash table used by the cache passed
+** as the first argument.
+**
+** The PCache mutex must be held when this function is called.
+*/
+static void pcache1ResizeHash(PCache1 *p){
+  PgHdr1 **apNew;
+  unsigned int nNew;
+  unsigned int i;
+
+  assert( sqlite3_mutex_held(p->pGroup->mutex) );
+
+  nNew = p->nHash*2;
+  if( nNew<256 ){
+    nNew = 256;
+  }
+
+  pcache1LeaveMutex(p->pGroup);
+  if( p->nHash ){ sqlite3BeginBenignMalloc(); }
+  apNew = (PgHdr1 **)sqlite3MallocZero(sizeof(PgHdr1 *)*nNew);
+  if( p->nHash ){ sqlite3EndBenignMalloc(); }
+  pcache1EnterMutex(p->pGroup);
+  if( apNew ){
+    for(i=0; i<p->nHash; i++){
+      PgHdr1 *pPage;
+      PgHdr1 *pNext = p->apHash[i];
+      while( (pPage = pNext)!=0 ){
+        unsigned int h = pPage->iKey % nNew;
+        pNext = pPage->pNext;
+        pPage->pNext = apNew[h];
+        apNew[h] = pPage;
+      }
+    }
+    sqlite3_free(p->apHash);
+    p->apHash = apNew;
+    p->nHash = nNew;
+  }
+}
+
+/*
+** This function is used internally to remove the page pPage from the
+** PGroup LRU list, if is part of it. If pPage is not part of the PGroup
+** LRU list, then this function is a no-op.
+**
+** The PGroup mutex must be held when this function is called.
+*/
+static PgHdr1 *pcache1PinPage(PgHdr1 *pPage){
+  assert( pPage!=0 );
+  assert( PAGE_IS_UNPINNED(pPage) );
+  assert( pPage->pLruNext );
+  assert( pPage->pLruPrev );
+  assert( sqlite3_mutex_held(pPage->pCache->pGroup->mutex) );
+  pPage->pLruPrev->pLruNext = pPage->pLruNext;
+  pPage->pLruNext->pLruPrev = pPage->pLruPrev;
+  pPage->pLruNext = 0;
+  /* pPage->pLruPrev = 0;
+  ** No need to clear pLruPrev as it is never accessed if pLruNext is 0 */
+  assert( pPage->isAnchor==0 );
+  assert( pPage->pCache->pGroup->lru.isAnchor==1 );
+  pPage->pCache->nRecyclable--;
+  return pPage;
+}
+
+
+/*
+** Remove the page supplied as an argument from the hash table
+** (PCache1.apHash structure) that it is currently stored in.
+** Also free the page if freePage is true.
+**
+** The PGroup mutex must be held when this function is called.
+*/
+static void pcache1RemoveFromHash(PgHdr1 *pPage, int freeFlag){
+  unsigned int h;
+  PCache1 *pCache = pPage->pCache;
+  PgHdr1 **pp;
+
+  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
+  h = pPage->iKey % pCache->nHash;
+  for(pp=&pCache->apHash[h]; (*pp)!=pPage; pp=&(*pp)->pNext);
+  *pp = (*pp)->pNext;
+
+  pCache->nPage--;
+  if( freeFlag ) pcache1FreePage(pPage);
+}
+
+/*
+** If there are currently more than nMaxPage pages allocated, try
+** to recycle pages to reduce the number allocated to nMaxPage.
+*/
+static void pcache1EnforceMaxPage(PCache1 *pCache){
+  PGroup *pGroup = pCache->pGroup;
+  PgHdr1 *p;
+  assert( sqlite3_mutex_held(pGroup->mutex) );
+  while( pGroup->nPurgeable>pGroup->nMaxPage
+      && (p=pGroup->lru.pLruPrev)->isAnchor==0
+  ){
+    assert( p->pCache->pGroup==pGroup );
+    assert( PAGE_IS_UNPINNED(p) );
+    pcache1PinPage(p);
+    pcache1RemoveFromHash(p, 1);
+  }
+  if( pCache->nPage==0 && pCache->pBulk ){
+    sqlite3_free(pCache->pBulk);
+    pCache->pBulk = pCache->pFree = 0;
+  }
+}
+
+/*
+** Discard all pages from cache pCache with a page number (key value)
+** greater than or equal to iLimit. Any pinned pages that meet this
+** criteria are unpinned before they are discarded.
+**
+** The PCache mutex must be held when this function is called.
+*/
+static void pcache1TruncateUnsafe(
+  PCache1 *pCache,             /* The cache to truncate */
+  unsigned int iLimit          /* Drop pages with this pgno or larger */
+){
+  TESTONLY( int nPage = 0; )  /* To assert pCache->nPage is correct */
+  unsigned int h, iStop;
+  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
+  assert( pCache->iMaxKey >= iLimit );
+  assert( pCache->nHash > 0 );
+  if( pCache->iMaxKey - iLimit < pCache->nHash ){
+    /* If we are just shaving the last few pages off the end of the
+    ** cache, then there is no point in scanning the entire hash table.
+    ** Only scan those hash slots that might contain pages that need to
+    ** be removed. */
+    h = iLimit % pCache->nHash;
+    iStop = pCache->iMaxKey % pCache->nHash;
+    TESTONLY( nPage = -10; )  /* Disable the pCache->nPage validity check */
+  }else{
+    /* This is the general case where many pages are being removed.
+    ** It is necessary to scan the entire hash table */
+    h = pCache->nHash/2;
+    iStop = h - 1;
+  }
+  for(;;){
+    PgHdr1 **pp;
+    PgHdr1 *pPage;
+    assert( h<pCache->nHash );
+    pp = &pCache->apHash[h];
+    while( (pPage = *pp)!=0 ){
+      if( pPage->iKey>=iLimit ){
+        pCache->nPage--;
+        *pp = pPage->pNext;
+        if( PAGE_IS_UNPINNED(pPage) ) pcache1PinPage(pPage);
+        pcache1FreePage(pPage);
+      }else{
+        pp = &pPage->pNext;
+        TESTONLY( if( nPage>=0 ) nPage++; )
+      }
+    }
+    if( h==iStop ) break;
+    h = (h+1) % pCache->nHash;
+  }
+  assert( nPage<0 || pCache->nPage==(unsigned)nPage );
+}
+
+/******************************************************************************/
+/******** sqlite3_pcache Methods **********************************************/
+
+/*
+** Implementation of the sqlite3_pcache.xInit method.
+*/
+static int pcache1Init(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  assert( pcache1.isInit==0 );
+  memset(&pcache1, 0, sizeof(pcache1));
+
+
+  /*
+  ** The pcache1.separateCache variable is true if each PCache has its own
+  ** private PGroup (mode-1).  pcache1.separateCache is false if the single
+  ** PGroup in pcache1.grp is used for all page caches (mode-2).
+  **
+  **   *  Always use a unified cache (mode-2) if ENABLE_MEMORY_MANAGEMENT
+  **
+  **   *  Use a unified cache in single-threaded applications that have
+  **      configured a start-time buffer for use as page-cache memory using
+  **      sqlite3_config(SQLITE_CONFIG_PAGECACHE, pBuf, sz, N) with non-NULL
+  **      pBuf argument.
+  **
+  **   *  Otherwise use separate caches (mode-1)
+  */
+#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT)
+  pcache1.separateCache = 0;
+#elif SQLITE_THREADSAFE
+  pcache1.separateCache = sqlite3GlobalConfig.pPage==0
+                          || sqlite3GlobalConfig.bCoreMutex>0;
+#else
+  pcache1.separateCache = sqlite3GlobalConfig.pPage==0;
+#endif
+
+#if SQLITE_THREADSAFE
+  if( sqlite3GlobalConfig.bCoreMutex ){
+    pcache1.grp.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_LRU);
+    pcache1.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_PMEM);
+  }
+#endif
+  if( pcache1.separateCache
+   && sqlite3GlobalConfig.nPage!=0
+   && sqlite3GlobalConfig.pPage==0
+  ){
+    pcache1.nInitPage = sqlite3GlobalConfig.nPage;
+  }else{
+    pcache1.nInitPage = 0;
+  }
+  pcache1.grp.mxPinned = 10;
+  pcache1.isInit = 1;
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of the sqlite3_pcache.xShutdown method.
+** Note that the static mutex allocated in xInit does
+** not need to be freed.
+*/
+static void pcache1Shutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  assert( pcache1.isInit!=0 );
+  memset(&pcache1, 0, sizeof(pcache1));
+}
+
+/* forward declaration */
+static void pcache1Destroy(sqlite3_pcache *p);
+
+/*
+** Implementation of the sqlite3_pcache.xCreate method.
+**
+** Allocate a new cache.
+*/
+static sqlite3_pcache *pcache1Create(int szPage, int szExtra, int bPurgeable){
+  PCache1 *pCache;      /* The newly created page cache */
+  PGroup *pGroup;       /* The group the new page cache will belong to */
+  int sz;               /* Bytes of memory required to allocate the new cache */
+
+  assert( (szPage & (szPage-1))==0 && szPage>=512 && szPage<=65536 );
+  assert( szExtra < 300 );
+
+  sz = sizeof(PCache1) + sizeof(PGroup)*pcache1.separateCache;
+  pCache = (PCache1 *)sqlite3MallocZero(sz);
+  if( pCache ){
+    if( pcache1.separateCache ){
+      pGroup = (PGroup*)&pCache[1];
+      pGroup->mxPinned = 10;
+    }else{
+      pGroup = &pcache1.grp;
+    }
+    pcache1EnterMutex(pGroup);
+    if( pGroup->lru.isAnchor==0 ){
+      pGroup->lru.isAnchor = 1;
+      pGroup->lru.pLruPrev = pGroup->lru.pLruNext = &pGroup->lru;
+    }
+    pCache->pGroup = pGroup;
+    pCache->szPage = szPage;
+    pCache->szExtra = szExtra;
+    pCache->szAlloc = szPage + szExtra + ROUND8(sizeof(PgHdr1));
+    pCache->bPurgeable = (bPurgeable ? 1 : 0);
+    pcache1ResizeHash(pCache);
+    if( bPurgeable ){
+      pCache->nMin = 10;
+      pGroup->nMinPage += pCache->nMin;
+      pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
+      pCache->pnPurgeable = &pGroup->nPurgeable;
+    }else{
+      pCache->pnPurgeable = &pCache->nPurgeableDummy;
+    }
+    pcache1LeaveMutex(pGroup);
+    if( pCache->nHash==0 ){
+      pcache1Destroy((sqlite3_pcache*)pCache);
+      pCache = 0;
+    }
+  }
+  return (sqlite3_pcache *)pCache;
+}
+
+/*
+** Implementation of the sqlite3_pcache.xCachesize method.
+**
+** Configure the cache_size limit for a cache.
+*/
+static void pcache1Cachesize(sqlite3_pcache *p, int nMax){
+  PCache1 *pCache = (PCache1 *)p;
+  u32 n;
+  assert( nMax>=0 );
+  if( pCache->bPurgeable ){
+    PGroup *pGroup = pCache->pGroup;
+    pcache1EnterMutex(pGroup);
+    n = (u32)nMax;
+    if( n > 0x7fff0000 - pGroup->nMaxPage + pCache->nMax ){
+      n = 0x7fff0000 - pGroup->nMaxPage + pCache->nMax;
+    }
+    pGroup->nMaxPage += (n - pCache->nMax);
+    pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
+    pCache->nMax = n;
+    pCache->n90pct = pCache->nMax*9/10;
+    pcache1EnforceMaxPage(pCache);
+    pcache1LeaveMutex(pGroup);
+  }
+}
+
+/*
+** Implementation of the sqlite3_pcache.xShrink method.
+**
+** Free up as much memory as possible.
+*/
+static void pcache1Shrink(sqlite3_pcache *p){
+  PCache1 *pCache = (PCache1*)p;
+  if( pCache->bPurgeable ){
+    PGroup *pGroup = pCache->pGroup;
+    unsigned int savedMaxPage;
+    pcache1EnterMutex(pGroup);
+    savedMaxPage = pGroup->nMaxPage;
+    pGroup->nMaxPage = 0;
+    pcache1EnforceMaxPage(pCache);
+    pGroup->nMaxPage = savedMaxPage;
+    pcache1LeaveMutex(pGroup);
+  }
+}
+
+/*
+** Implementation of the sqlite3_pcache.xPagecount method.
+*/
+static int pcache1Pagecount(sqlite3_pcache *p){
+  int n;
+  PCache1 *pCache = (PCache1*)p;
+  pcache1EnterMutex(pCache->pGroup);
+  n = pCache->nPage;
+  pcache1LeaveMutex(pCache->pGroup);
+  return n;
+}
+
+
+/*
+** Implement steps 3, 4, and 5 of the pcache1Fetch() algorithm described
+** in the header of the pcache1Fetch() procedure.
+**
+** This steps are broken out into a separate procedure because they are
+** usually not needed, and by avoiding the stack initialization required
+** for these steps, the main pcache1Fetch() procedure can run faster.
+*/
+static SQLITE_NOINLINE PgHdr1 *pcache1FetchStage2(
+  PCache1 *pCache,
+  unsigned int iKey,
+  int createFlag
+){
+  unsigned int nPinned;
+  PGroup *pGroup = pCache->pGroup;
+  PgHdr1 *pPage = 0;
+
+  /* Step 3: Abort if createFlag is 1 but the cache is nearly full */
+  assert( pCache->nPage >= pCache->nRecyclable );
+  nPinned = pCache->nPage - pCache->nRecyclable;
+  assert( pGroup->mxPinned == pGroup->nMaxPage + 10 - pGroup->nMinPage );
+  assert( pCache->n90pct == pCache->nMax*9/10 );
+  if( createFlag==1 && (
+        nPinned>=pGroup->mxPinned
+     || nPinned>=pCache->n90pct
+     || (pcache1UnderMemoryPressure(pCache) && pCache->nRecyclable<nPinned)
+  )){
+    return 0;
+  }
+
+  if( pCache->nPage>=pCache->nHash ) pcache1ResizeHash(pCache);
+  assert( pCache->nHash>0 && pCache->apHash );
+
+  /* Step 4. Try to recycle a page. */
+  if( pCache->bPurgeable
+   && !pGroup->lru.pLruPrev->isAnchor
+   && ((pCache->nPage+1>=pCache->nMax) || pcache1UnderMemoryPressure(pCache))
+  ){
+    PCache1 *pOther;
+    pPage = pGroup->lru.pLruPrev;
+    assert( PAGE_IS_UNPINNED(pPage) );
+    pcache1RemoveFromHash(pPage, 0);
+    pcache1PinPage(pPage);
+    pOther = pPage->pCache;
+    if( pOther->szAlloc != pCache->szAlloc ){
+      pcache1FreePage(pPage);
+      pPage = 0;
+    }else{
+      pGroup->nPurgeable -= (pOther->bPurgeable - pCache->bPurgeable);
+    }
+  }
+
+  /* Step 5. If a usable page buffer has still not been found,
+  ** attempt to allocate a new one.
+  */
+  if( !pPage ){
+    pPage = pcache1AllocPage(pCache, createFlag==1);
+  }
+
+  if( pPage ){
+    unsigned int h = iKey % pCache->nHash;
+    pCache->nPage++;
+    pPage->iKey = iKey;
+    pPage->pNext = pCache->apHash[h];
+    pPage->pCache = pCache;
+    pPage->pLruNext = 0;
+    /* pPage->pLruPrev = 0;
+    ** No need to clear pLruPrev since it is not accessed when pLruNext==0 */
+    *(void **)pPage->page.pExtra = 0;
+    pCache->apHash[h] = pPage;
+    if( iKey>pCache->iMaxKey ){
+      pCache->iMaxKey = iKey;
+    }
+  }
+  return pPage;
+}
+
+/*
+** Implementation of the sqlite3_pcache.xFetch method.
+**
+** Fetch a page by key value.
+**
+** Whether or not a new page may be allocated by this function depends on
+** the value of the createFlag argument.  0 means do not allocate a new
+** page.  1 means allocate a new page if space is easily available.  2
+** means to try really hard to allocate a new page.
+**
+** For a non-purgeable cache (a cache used as the storage for an in-memory
+** database) there is really no difference between createFlag 1 and 2.  So
+** the calling function (pcache.c) will never have a createFlag of 1 on
+** a non-purgeable cache.
+**
+** There are three different approaches to obtaining space for a page,
+** depending on the value of parameter createFlag (which may be 0, 1 or 2).
+**
+**   1. Regardless of the value of createFlag, the cache is searched for a
+**      copy of the requested page. If one is found, it is returned.
+**
+**   2. If createFlag==0 and the page is not already in the cache, NULL is
+**      returned.
+**
+**   3. If createFlag is 1, and the page is not already in the cache, then
+**      return NULL (do not allocate a new page) if any of the following
+**      conditions are true:
+**
+**       (a) the number of pages pinned by the cache is greater than
+**           PCache1.nMax, or
+**
+**       (b) the number of pages pinned by the cache is greater than
+**           the sum of nMax for all purgeable caches, less the sum of
+**           nMin for all other purgeable caches, or
+**
+**   4. If none of the first three conditions apply and the cache is marked
+**      as purgeable, and if one of the following is true:
+**
+**       (a) The number of pages allocated for the cache is already
+**           PCache1.nMax, or
+**
+**       (b) The number of pages allocated for all purgeable caches is
+**           already equal to or greater than the sum of nMax for all
+**           purgeable caches,
+**
+**       (c) The system is under memory pressure and wants to avoid
+**           unnecessary pages cache entry allocations
+**
+**      then attempt to recycle a page from the LRU list. If it is the right
+**      size, return the recycled buffer. Otherwise, free the buffer and
+**      proceed to step 5.
+**
+**   5. Otherwise, allocate and return a new page buffer.
+**
+** There are two versions of this routine.  pcache1FetchWithMutex() is
+** the general case.  pcache1FetchNoMutex() is a faster implementation for
+** the common case where pGroup->mutex is NULL.  The pcache1Fetch() wrapper
+** invokes the appropriate routine.
+*/
+static PgHdr1 *pcache1FetchNoMutex(
+  sqlite3_pcache *p,
+  unsigned int iKey,
+  int createFlag
+){
+  PCache1 *pCache = (PCache1 *)p;
+  PgHdr1 *pPage = 0;
+
+  /* Step 1: Search the hash table for an existing entry. */
+  pPage = pCache->apHash[iKey % pCache->nHash];
+  while( pPage && pPage->iKey!=iKey ){ pPage = pPage->pNext; }
+
+  /* Step 2: If the page was found in the hash table, then return it.
+  ** If the page was not in the hash table and createFlag is 0, abort.
+  ** Otherwise (page not in hash and createFlag!=0) continue with
+  ** subsequent steps to try to create the page. */
+  if( pPage ){
+    if( PAGE_IS_UNPINNED(pPage) ){
+      return pcache1PinPage(pPage);
+    }else{
+      return pPage;
+    }
+  }else if( createFlag ){
+    /* Steps 3, 4, and 5 implemented by this subroutine */
+    return pcache1FetchStage2(pCache, iKey, createFlag);
+  }else{
+    return 0;
+  }
+}
+#if PCACHE1_MIGHT_USE_GROUP_MUTEX
+static PgHdr1 *pcache1FetchWithMutex(
+  sqlite3_pcache *p,
+  unsigned int iKey,
+  int createFlag
+){
+  PCache1 *pCache = (PCache1 *)p;
+  PgHdr1 *pPage;
+
+  pcache1EnterMutex(pCache->pGroup);
+  pPage = pcache1FetchNoMutex(p, iKey, createFlag);
+  assert( pPage==0 || pCache->iMaxKey>=iKey );
+  pcache1LeaveMutex(pCache->pGroup);
+  return pPage;
+}
+#endif
+static sqlite3_pcache_page *pcache1Fetch(
+  sqlite3_pcache *p,
+  unsigned int iKey,
+  int createFlag
+){
+#if PCACHE1_MIGHT_USE_GROUP_MUTEX || defined(SQLITE_DEBUG)
+  PCache1 *pCache = (PCache1 *)p;
+#endif
+
+  assert( offsetof(PgHdr1,page)==0 );
+  assert( pCache->bPurgeable || createFlag!=1 );
+  assert( pCache->bPurgeable || pCache->nMin==0 );
+  assert( pCache->bPurgeable==0 || pCache->nMin==10 );
+  assert( pCache->nMin==0 || pCache->bPurgeable );
+  assert( pCache->nHash>0 );
+#if PCACHE1_MIGHT_USE_GROUP_MUTEX
+  if( pCache->pGroup->mutex ){
+    return (sqlite3_pcache_page*)pcache1FetchWithMutex(p, iKey, createFlag);
+  }else
+#endif
+  {
+    return (sqlite3_pcache_page*)pcache1FetchNoMutex(p, iKey, createFlag);
+  }
+}
+
+
+/*
+** Implementation of the sqlite3_pcache.xUnpin method.
+**
+** Mark a page as unpinned (eligible for asynchronous recycling).
+*/
+static void pcache1Unpin(
+  sqlite3_pcache *p,
+  sqlite3_pcache_page *pPg,
+  int reuseUnlikely
+){
+  PCache1 *pCache = (PCache1 *)p;
+  PgHdr1 *pPage = (PgHdr1 *)pPg;
+  PGroup *pGroup = pCache->pGroup;
+
+  assert( pPage->pCache==pCache );
+  pcache1EnterMutex(pGroup);
+
+  /* It is an error to call this function if the page is already
+  ** part of the PGroup LRU list.
+  */
+  assert( pPage->pLruNext==0 );
+  assert( PAGE_IS_PINNED(pPage) );
+
+  if( reuseUnlikely || pGroup->nPurgeable>pGroup->nMaxPage ){
+    pcache1RemoveFromHash(pPage, 1);
+  }else{
+    /* Add the page to the PGroup LRU list. */
+    PgHdr1 **ppFirst = &pGroup->lru.pLruNext;
+    pPage->pLruPrev = &pGroup->lru;
+    (pPage->pLruNext = *ppFirst)->pLruPrev = pPage;
+    *ppFirst = pPage;
+    pCache->nRecyclable++;
+  }
+
+  pcache1LeaveMutex(pCache->pGroup);
+}
+
+/*
+** Implementation of the sqlite3_pcache.xRekey method.
+*/
+static void pcache1Rekey(
+  sqlite3_pcache *p,
+  sqlite3_pcache_page *pPg,
+  unsigned int iOld,
+  unsigned int iNew
+){
+  PCache1 *pCache = (PCache1 *)p;
+  PgHdr1 *pPage = (PgHdr1 *)pPg;
+  PgHdr1 **pp;
+  unsigned int hOld, hNew;
+  assert( pPage->iKey==iOld );
+  assert( pPage->pCache==pCache );
+  assert( iOld!=iNew );               /* The page number really is changing */
+
+  pcache1EnterMutex(pCache->pGroup);
+
+  assert( pcache1FetchNoMutex(p, iOld, 0)==pPage ); /* pPg really is iOld */
+  hOld = iOld%pCache->nHash;
+  pp = &pCache->apHash[hOld];
+  while( (*pp)!=pPage ){
+    pp = &(*pp)->pNext;
+  }
+  *pp = pPage->pNext;
+
+  assert( pcache1FetchNoMutex(p, iNew, 0)==0 ); /* iNew not in cache */
+  hNew = iNew%pCache->nHash;
+  pPage->iKey = iNew;
+  pPage->pNext = pCache->apHash[hNew];
+  pCache->apHash[hNew] = pPage;
+  if( iNew>pCache->iMaxKey ){
+    pCache->iMaxKey = iNew;
+  }
+
+  pcache1LeaveMutex(pCache->pGroup);
+}
+
+/*
+** Implementation of the sqlite3_pcache.xTruncate method.
+**
+** Discard all unpinned pages in the cache with a page number equal to
+** or greater than parameter iLimit. Any pinned pages with a page number
+** equal to or greater than iLimit are implicitly unpinned.
+*/
+static void pcache1Truncate(sqlite3_pcache *p, unsigned int iLimit){
+  PCache1 *pCache = (PCache1 *)p;
+  pcache1EnterMutex(pCache->pGroup);
+  if( iLimit<=pCache->iMaxKey ){
+    pcache1TruncateUnsafe(pCache, iLimit);
+    pCache->iMaxKey = iLimit-1;
+  }
+  pcache1LeaveMutex(pCache->pGroup);
+}
+
+/*
+** Implementation of the sqlite3_pcache.xDestroy method.
+**
+** Destroy a cache allocated using pcache1Create().
+*/
+static void pcache1Destroy(sqlite3_pcache *p){
+  PCache1 *pCache = (PCache1 *)p;
+  PGroup *pGroup = pCache->pGroup;
+  assert( pCache->bPurgeable || (pCache->nMax==0 && pCache->nMin==0) );
+  pcache1EnterMutex(pGroup);
+  if( pCache->nPage ) pcache1TruncateUnsafe(pCache, 0);
+  assert( pGroup->nMaxPage >= pCache->nMax );
+  pGroup->nMaxPage -= pCache->nMax;
+  assert( pGroup->nMinPage >= pCache->nMin );
+  pGroup->nMinPage -= pCache->nMin;
+  pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
+  pcache1EnforceMaxPage(pCache);
+  pcache1LeaveMutex(pGroup);
+  sqlite3_free(pCache->pBulk);
+  sqlite3_free(pCache->apHash);
+  sqlite3_free(pCache);
+}
+
+/*
+** This function is called during initialization (sqlite3_initialize()) to
+** install the default pluggable cache module, assuming the user has not
+** already provided an alternative.
+*/
+SQLITE_PRIVATE void sqlite3PCacheSetDefault(void){
+  static const sqlite3_pcache_methods2 defaultMethods = {
+    1,                       /* iVersion */
+    0,                       /* pArg */
+    pcache1Init,             /* xInit */
+    pcache1Shutdown,         /* xShutdown */
+    pcache1Create,           /* xCreate */
+    pcache1Cachesize,        /* xCachesize */
+    pcache1Pagecount,        /* xPagecount */
+    pcache1Fetch,            /* xFetch */
+    pcache1Unpin,            /* xUnpin */
+    pcache1Rekey,            /* xRekey */
+    pcache1Truncate,         /* xTruncate */
+    pcache1Destroy,          /* xDestroy */
+    pcache1Shrink            /* xShrink */
+  };
+  sqlite3_config(SQLITE_CONFIG_PCACHE2, &defaultMethods);
+}
+
+/*
+** Return the size of the header on each page of this PCACHE implementation.
+*/
+SQLITE_PRIVATE int sqlite3HeaderSizePcache1(void){ return ROUND8(sizeof(PgHdr1)); }
+
+/*
+** Return the global mutex used by this PCACHE implementation.  The
+** sqlite3_status() routine needs access to this mutex.
+*/
+SQLITE_PRIVATE sqlite3_mutex *sqlite3Pcache1Mutex(void){
+  return pcache1.mutex;
+}
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/*
+** This function is called to free superfluous dynamically allocated memory
+** held by the pager system. Memory in use by any SQLite pager allocated
+** by the current thread may be sqlite3_free()ed.
+**
+** nReq is the number of bytes of memory required. Once this much has
+** been released, the function returns. The return value is the total number
+** of bytes of memory released.
+*/
+SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int nReq){
+  int nFree = 0;
+  assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
+  assert( sqlite3_mutex_notheld(pcache1.mutex) );
+  if( sqlite3GlobalConfig.pPage==0 ){
+    PgHdr1 *p;
+    pcache1EnterMutex(&pcache1.grp);
+    while( (nReq<0 || nFree<nReq)
+       &&  (p=pcache1.grp.lru.pLruPrev)!=0
+       &&  p->isAnchor==0
+    ){
+      nFree += pcache1MemSize(p->page.pBuf);
+      assert( PAGE_IS_UNPINNED(p) );
+      pcache1PinPage(p);
+      pcache1RemoveFromHash(p, 1);
+    }
+    pcache1LeaveMutex(&pcache1.grp);
+  }
+  return nFree;
+}
+#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */
+
+#ifdef SQLITE_TEST
+/*
+** This function is used by test procedures to inspect the internal state
+** of the global cache.
+*/
+SQLITE_PRIVATE void sqlite3PcacheStats(
+  int *pnCurrent,      /* OUT: Total number of pages cached */
+  int *pnMax,          /* OUT: Global maximum cache size */
+  int *pnMin,          /* OUT: Sum of PCache1.nMin for purgeable caches */
+  int *pnRecyclable    /* OUT: Total number of pages available for recycling */
+){
+  PgHdr1 *p;
+  int nRecyclable = 0;
+  for(p=pcache1.grp.lru.pLruNext; p && !p->isAnchor; p=p->pLruNext){
+    assert( PAGE_IS_UNPINNED(p) );
+    nRecyclable++;
+  }
+  *pnCurrent = pcache1.grp.nPurgeable;
+  *pnMax = (int)pcache1.grp.nMaxPage;
+  *pnMin = (int)pcache1.grp.nMinPage;
+  *pnRecyclable = nRecyclable;
+}
+#endif
+
+/************** End of pcache1.c *********************************************/
+/************** Begin file rowset.c ******************************************/
+/*
+** 2008 December 3
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This module implements an object we call a "RowSet".
+**
+** The RowSet object is a collection of rowids.  Rowids
+** are inserted into the RowSet in an arbitrary order.  Inserts
+** can be intermixed with tests to see if a given rowid has been
+** previously inserted into the RowSet.
+**
+** After all inserts are finished, it is possible to extract the
+** elements of the RowSet in sorted order.  Once this extraction
+** process has started, no new elements may be inserted.
+**
+** Hence, the primitive operations for a RowSet are:
+**
+**    CREATE
+**    INSERT
+**    TEST
+**    SMALLEST
+**    DESTROY
+**
+** The CREATE and DESTROY primitives are the constructor and destructor,
+** obviously.  The INSERT primitive adds a new element to the RowSet.
+** TEST checks to see if an element is already in the RowSet.  SMALLEST
+** extracts the least value from the RowSet.
+**
+** The INSERT primitive might allocate additional memory.  Memory is
+** allocated in chunks so most INSERTs do no allocation.  There is an
+** upper bound on the size of allocated memory.  No memory is freed
+** until DESTROY.
+**
+** The TEST primitive includes a "batch" number.  The TEST primitive
+** will only see elements that were inserted before the last change
+** in the batch number.  In other words, if an INSERT occurs between
+** two TESTs where the TESTs have the same batch number, then the
+** value added by the INSERT will not be visible to the second TEST.
+** The initial batch number is zero, so if the very first TEST contains
+** a non-zero batch number, it will see all prior INSERTs.
+**
+** No INSERTs may occurs after a SMALLEST.  An assertion will fail if
+** that is attempted.
+**
+** The cost of an INSERT is roughly constant.  (Sometimes new memory
+** has to be allocated on an INSERT.)  The cost of a TEST with a new
+** batch number is O(NlogN) where N is the number of elements in the RowSet.
+** The cost of a TEST using the same batch number is O(logN).  The cost
+** of the first SMALLEST is O(NlogN).  Second and subsequent SMALLEST
+** primitives are constant time.  The cost of DESTROY is O(N).
+**
+** TEST and SMALLEST may not be used by the same RowSet.  This used to
+** be possible, but the feature was not used, so it was removed in order
+** to simplify the code.
+*/
+/* #include "sqliteInt.h" */
+
+
+/*
+** Target size for allocation chunks.
+*/
+#define ROWSET_ALLOCATION_SIZE 1024
+
+/*
+** The number of rowset entries per allocation chunk.
+*/
+#define ROWSET_ENTRY_PER_CHUNK  \
+                       ((ROWSET_ALLOCATION_SIZE-8)/sizeof(struct RowSetEntry))
+
+/*
+** Each entry in a RowSet is an instance of the following object.
+**
+** This same object is reused to store a linked list of trees of RowSetEntry
+** objects.  In that alternative use, pRight points to the next entry
+** in the list, pLeft points to the tree, and v is unused.  The
+** RowSet.pForest value points to the head of this forest list.
+*/
+struct RowSetEntry {
+  i64 v;                        /* ROWID value for this entry */
+  struct RowSetEntry *pRight;   /* Right subtree (larger entries) or list */
+  struct RowSetEntry *pLeft;    /* Left subtree (smaller entries) */
+};
+
+/*
+** RowSetEntry objects are allocated in large chunks (instances of the
+** following structure) to reduce memory allocation overhead.  The
+** chunks are kept on a linked list so that they can be deallocated
+** when the RowSet is destroyed.
+*/
+struct RowSetChunk {
+  struct RowSetChunk *pNextChunk;        /* Next chunk on list of them all */
+  struct RowSetEntry aEntry[ROWSET_ENTRY_PER_CHUNK]; /* Allocated entries */
+};
+
+/*
+** A RowSet in an instance of the following structure.
+**
+** A typedef of this structure if found in sqliteInt.h.
+*/
+struct RowSet {
+  struct RowSetChunk *pChunk;    /* List of all chunk allocations */
+  sqlite3 *db;                   /* The database connection */
+  struct RowSetEntry *pEntry;    /* List of entries using pRight */
+  struct RowSetEntry *pLast;     /* Last entry on the pEntry list */
+  struct RowSetEntry *pFresh;    /* Source of new entry objects */
+  struct RowSetEntry *pForest;   /* List of binary trees of entries */
+  u16 nFresh;                    /* Number of objects on pFresh */
+  u16 rsFlags;                   /* Various flags */
+  int iBatch;                    /* Current insert batch */
+};
+
+/*
+** Allowed values for RowSet.rsFlags
+*/
+#define ROWSET_SORTED  0x01   /* True if RowSet.pEntry is sorted */
+#define ROWSET_NEXT    0x02   /* True if sqlite3RowSetNext() has been called */
+
+/*
+** Allocate a RowSet object.  Return NULL if a memory allocation
+** error occurs.
+*/
+SQLITE_PRIVATE RowSet *sqlite3RowSetInit(sqlite3 *db){
+  RowSet *p = sqlite3DbMallocRawNN(db, sizeof(*p));
+  if( p ){
+    int N = sqlite3DbMallocSize(db, p);
+    p->pChunk = 0;
+    p->db = db;
+    p->pEntry = 0;
+    p->pLast = 0;
+    p->pForest = 0;
+    p->pFresh = (struct RowSetEntry*)(ROUND8(sizeof(*p)) + (char*)p);
+    p->nFresh = (u16)((N - ROUND8(sizeof(*p)))/sizeof(struct RowSetEntry));
+    p->rsFlags = ROWSET_SORTED;
+    p->iBatch = 0;
+  }
+  return p;
+}
+
+/*
+** Deallocate all chunks from a RowSet.  This frees all memory that
+** the RowSet has allocated over its lifetime.  This routine is
+** the destructor for the RowSet.
+*/
+SQLITE_PRIVATE void sqlite3RowSetClear(void *pArg){
+  RowSet *p = (RowSet*)pArg;
+  struct RowSetChunk *pChunk, *pNextChunk;
+  for(pChunk=p->pChunk; pChunk; pChunk = pNextChunk){
+    pNextChunk = pChunk->pNextChunk;
+    sqlite3DbFree(p->db, pChunk);
+  }
+  p->pChunk = 0;
+  p->nFresh = 0;
+  p->pEntry = 0;
+  p->pLast = 0;
+  p->pForest = 0;
+  p->rsFlags = ROWSET_SORTED;
+}
+
+/*
+** Deallocate all chunks from a RowSet.  This frees all memory that
+** the RowSet has allocated over its lifetime.  This routine is
+** the destructor for the RowSet.
+*/
+SQLITE_PRIVATE void sqlite3RowSetDelete(void *pArg){
+  sqlite3RowSetClear(pArg);
+  sqlite3DbFree(((RowSet*)pArg)->db, pArg);
+}
+
+/*
+** Allocate a new RowSetEntry object that is associated with the
+** given RowSet.  Return a pointer to the new and completely uninitialized
+** object.
+**
+** In an OOM situation, the RowSet.db->mallocFailed flag is set and this
+** routine returns NULL.
+*/
+static struct RowSetEntry *rowSetEntryAlloc(RowSet *p){
+  assert( p!=0 );
+  if( p->nFresh==0 ){  /*OPTIMIZATION-IF-FALSE*/
+    /* We could allocate a fresh RowSetEntry each time one is needed, but it
+    ** is more efficient to pull a preallocated entry from the pool */
+    struct RowSetChunk *pNew;
+    pNew = sqlite3DbMallocRawNN(p->db, sizeof(*pNew));
+    if( pNew==0 ){
+      return 0;
+    }
+    pNew->pNextChunk = p->pChunk;
+    p->pChunk = pNew;
+    p->pFresh = pNew->aEntry;
+    p->nFresh = ROWSET_ENTRY_PER_CHUNK;
+  }
+  p->nFresh--;
+  return p->pFresh++;
+}
+
+/*
+** Insert a new value into a RowSet.
+**
+** The mallocFailed flag of the database connection is set if a
+** memory allocation fails.
+*/
+SQLITE_PRIVATE void sqlite3RowSetInsert(RowSet *p, i64 rowid){
+  struct RowSetEntry *pEntry;  /* The new entry */
+  struct RowSetEntry *pLast;   /* The last prior entry */
+
+  /* This routine is never called after sqlite3RowSetNext() */
+  assert( p!=0 && (p->rsFlags & ROWSET_NEXT)==0 );
+
+  pEntry = rowSetEntryAlloc(p);
+  if( pEntry==0 ) return;
+  pEntry->v = rowid;
+  pEntry->pRight = 0;
+  pLast = p->pLast;
+  if( pLast ){
+    if( rowid<=pLast->v ){  /*OPTIMIZATION-IF-FALSE*/
+      /* Avoid unnecessary sorts by preserving the ROWSET_SORTED flags
+      ** where possible */
+      p->rsFlags &= ~ROWSET_SORTED;
+    }
+    pLast->pRight = pEntry;
+  }else{
+    p->pEntry = pEntry;
+  }
+  p->pLast = pEntry;
+}
+
+/*
+** Merge two lists of RowSetEntry objects.  Remove duplicates.
+**
+** The input lists are connected via pRight pointers and are
+** assumed to each already be in sorted order.
+*/
+static struct RowSetEntry *rowSetEntryMerge(
+  struct RowSetEntry *pA,    /* First sorted list to be merged */
+  struct RowSetEntry *pB     /* Second sorted list to be merged */
+){
+  struct RowSetEntry head;
+  struct RowSetEntry *pTail;
+
+  pTail = &head;
+  assert( pA!=0 && pB!=0 );
+  for(;;){
+    assert( pA->pRight==0 || pA->v<=pA->pRight->v );
+    assert( pB->pRight==0 || pB->v<=pB->pRight->v );
+    if( pA->v<=pB->v ){
+      if( pA->v<pB->v ) pTail = pTail->pRight = pA;
+      pA = pA->pRight;
+      if( pA==0 ){
+        pTail->pRight = pB;
+        break;
+      }
+    }else{
+      pTail = pTail->pRight = pB;
+      pB = pB->pRight;
+      if( pB==0 ){
+        pTail->pRight = pA;
+        break;
+      }
+    }
+  }
+  return head.pRight;
+}
+
+/*
+** Sort all elements on the list of RowSetEntry objects into order of
+** increasing v.
+*/
+static struct RowSetEntry *rowSetEntrySort(struct RowSetEntry *pIn){
+  unsigned int i;
+  struct RowSetEntry *pNext, *aBucket[40];
+
+  memset(aBucket, 0, sizeof(aBucket));
+  while( pIn ){
+    pNext = pIn->pRight;
+    pIn->pRight = 0;
+    for(i=0; aBucket[i]; i++){
+      pIn = rowSetEntryMerge(aBucket[i], pIn);
+      aBucket[i] = 0;
+    }
+    aBucket[i] = pIn;
+    pIn = pNext;
+  }
+  pIn = aBucket[0];
+  for(i=1; i<sizeof(aBucket)/sizeof(aBucket[0]); i++){
+    if( aBucket[i]==0 ) continue;
+    pIn = pIn ? rowSetEntryMerge(pIn, aBucket[i]) : aBucket[i];
+  }
+  return pIn;
+}
+
+
+/*
+** The input, pIn, is a binary tree (or subtree) of RowSetEntry objects.
+** Convert this tree into a linked list connected by the pRight pointers
+** and return pointers to the first and last elements of the new list.
+*/
+static void rowSetTreeToList(
+  struct RowSetEntry *pIn,         /* Root of the input tree */
+  struct RowSetEntry **ppFirst,    /* Write head of the output list here */
+  struct RowSetEntry **ppLast      /* Write tail of the output list here */
+){
+  assert( pIn!=0 );
+  if( pIn->pLeft ){
+    struct RowSetEntry *p;
+    rowSetTreeToList(pIn->pLeft, ppFirst, &p);
+    p->pRight = pIn;
+  }else{
+    *ppFirst = pIn;
+  }
+  if( pIn->pRight ){
+    rowSetTreeToList(pIn->pRight, &pIn->pRight, ppLast);
+  }else{
+    *ppLast = pIn;
+  }
+  assert( (*ppLast)->pRight==0 );
+}
+
+
+/*
+** Convert a sorted list of elements (connected by pRight) into a binary
+** tree with depth of iDepth.  A depth of 1 means the tree contains a single
+** node taken from the head of *ppList.  A depth of 2 means a tree with
+** three nodes.  And so forth.
+**
+** Use as many entries from the input list as required and update the
+** *ppList to point to the unused elements of the list.  If the input
+** list contains too few elements, then construct an incomplete tree
+** and leave *ppList set to NULL.
+**
+** Return a pointer to the root of the constructed binary tree.
+*/
+static struct RowSetEntry *rowSetNDeepTree(
+  struct RowSetEntry **ppList,
+  int iDepth
+){
+  struct RowSetEntry *p;         /* Root of the new tree */
+  struct RowSetEntry *pLeft;     /* Left subtree */
+  if( *ppList==0 ){ /*OPTIMIZATION-IF-TRUE*/
+    /* Prevent unnecessary deep recursion when we run out of entries */
+    return 0;
+  }
+  if( iDepth>1 ){   /*OPTIMIZATION-IF-TRUE*/
+    /* This branch causes a *balanced* tree to be generated.  A valid tree
+    ** is still generated without this branch, but the tree is wildly
+    ** unbalanced and inefficient. */
+    pLeft = rowSetNDeepTree(ppList, iDepth-1);
+    p = *ppList;
+    if( p==0 ){     /*OPTIMIZATION-IF-FALSE*/
+      /* It is safe to always return here, but the resulting tree
+      ** would be unbalanced */
+      return pLeft;
+    }
+    p->pLeft = pLeft;
+    *ppList = p->pRight;
+    p->pRight = rowSetNDeepTree(ppList, iDepth-1);
+  }else{
+    p = *ppList;
+    *ppList = p->pRight;
+    p->pLeft = p->pRight = 0;
+  }
+  return p;
+}
+
+/*
+** Convert a sorted list of elements into a binary tree. Make the tree
+** as deep as it needs to be in order to contain the entire list.
+*/
+static struct RowSetEntry *rowSetListToTree(struct RowSetEntry *pList){
+  int iDepth;           /* Depth of the tree so far */
+  struct RowSetEntry *p;       /* Current tree root */
+  struct RowSetEntry *pLeft;   /* Left subtree */
+
+  assert( pList!=0 );
+  p = pList;
+  pList = p->pRight;
+  p->pLeft = p->pRight = 0;
+  for(iDepth=1; pList; iDepth++){
+    pLeft = p;
+    p = pList;
+    pList = p->pRight;
+    p->pLeft = pLeft;
+    p->pRight = rowSetNDeepTree(&pList, iDepth);
+  }
+  return p;
+}
+
+/*
+** Extract the smallest element from the RowSet.
+** Write the element into *pRowid.  Return 1 on success.  Return
+** 0 if the RowSet is already empty.
+**
+** After this routine has been called, the sqlite3RowSetInsert()
+** routine may not be called again.
+**
+** This routine may not be called after sqlite3RowSetTest() has
+** been used.  Older versions of RowSet allowed that, but as the
+** capability was not used by the code generator, it was removed
+** for code economy.
+*/
+SQLITE_PRIVATE int sqlite3RowSetNext(RowSet *p, i64 *pRowid){
+  assert( p!=0 );
+  assert( p->pForest==0 );  /* Cannot be used with sqlite3RowSetText() */
+
+  /* Merge the forest into a single sorted list on first call */
+  if( (p->rsFlags & ROWSET_NEXT)==0 ){  /*OPTIMIZATION-IF-FALSE*/
+    if( (p->rsFlags & ROWSET_SORTED)==0 ){  /*OPTIMIZATION-IF-FALSE*/
+      p->pEntry = rowSetEntrySort(p->pEntry);
+    }
+    p->rsFlags |= ROWSET_SORTED|ROWSET_NEXT;
+  }
+
+  /* Return the next entry on the list */
+  if( p->pEntry ){
+    *pRowid = p->pEntry->v;
+    p->pEntry = p->pEntry->pRight;
+    if( p->pEntry==0 ){ /*OPTIMIZATION-IF-TRUE*/
+      /* Free memory immediately, rather than waiting on sqlite3_finalize() */
+      sqlite3RowSetClear(p);
+    }
+    return 1;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Check to see if element iRowid was inserted into the rowset as
+** part of any insert batch prior to iBatch.  Return 1 or 0.
+**
+** If this is the first test of a new batch and if there exist entries
+** on pRowSet->pEntry, then sort those entries into the forest at
+** pRowSet->pForest so that they can be tested.
+*/
+SQLITE_PRIVATE int sqlite3RowSetTest(RowSet *pRowSet, int iBatch, sqlite3_int64 iRowid){
+  struct RowSetEntry *p, *pTree;
+
+  /* This routine is never called after sqlite3RowSetNext() */
+  assert( pRowSet!=0 && (pRowSet->rsFlags & ROWSET_NEXT)==0 );
+
+  /* Sort entries into the forest on the first test of a new batch.
+  ** To save unnecessary work, only do this when the batch number changes.
+  */
+  if( iBatch!=pRowSet->iBatch ){  /*OPTIMIZATION-IF-FALSE*/
+    p = pRowSet->pEntry;
+    if( p ){
+      struct RowSetEntry **ppPrevTree = &pRowSet->pForest;
+      if( (pRowSet->rsFlags & ROWSET_SORTED)==0 ){ /*OPTIMIZATION-IF-FALSE*/
+        /* Only sort the current set of entries if they need it */
+        p = rowSetEntrySort(p);
+      }
+      for(pTree = pRowSet->pForest; pTree; pTree=pTree->pRight){
+        ppPrevTree = &pTree->pRight;
+        if( pTree->pLeft==0 ){
+          pTree->pLeft = rowSetListToTree(p);
+          break;
+        }else{
+          struct RowSetEntry *pAux, *pTail;
+          rowSetTreeToList(pTree->pLeft, &pAux, &pTail);
+          pTree->pLeft = 0;
+          p = rowSetEntryMerge(pAux, p);
+        }
+      }
+      if( pTree==0 ){
+        *ppPrevTree = pTree = rowSetEntryAlloc(pRowSet);
+        if( pTree ){
+          pTree->v = 0;
+          pTree->pRight = 0;
+          pTree->pLeft = rowSetListToTree(p);
+        }
+      }
+      pRowSet->pEntry = 0;
+      pRowSet->pLast = 0;
+      pRowSet->rsFlags |= ROWSET_SORTED;
+    }
+    pRowSet->iBatch = iBatch;
+  }
+
+  /* Test to see if the iRowid value appears anywhere in the forest.
+  ** Return 1 if it does and 0 if not.
+  */
+  for(pTree = pRowSet->pForest; pTree; pTree=pTree->pRight){
+    p = pTree->pLeft;
+    while( p ){
+      if( p->v<iRowid ){
+        p = p->pRight;
+      }else if( p->v>iRowid ){
+        p = p->pLeft;
+      }else{
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+/************** End of rowset.c **********************************************/
+/************** Begin file pager.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the implementation of the page cache subsystem or "pager".
+**
+** The pager is used to access a database disk file.  It implements
+** atomic commit and rollback through the use of a journal file that
+** is separate from the database file.  The pager also implements file
+** locking to prevent two processes from writing the same database
+** file simultaneously, or one process from reading the database while
+** another is writing.
+*/
+#ifndef SQLITE_OMIT_DISKIO
+/* #include "sqliteInt.h" */
+/************** Include wal.h in the middle of pager.c ***********************/
+/************** Begin file wal.h *********************************************/
+/*
+** 2010 February 1
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface to the write-ahead logging
+** system. Refer to the comments below and the header comment attached to
+** the implementation of each function in log.c for further details.
+*/
+
+#ifndef SQLITE_WAL_H
+#define SQLITE_WAL_H
+
+/* #include "sqliteInt.h" */
+
+/* Macros for extracting appropriate sync flags for either transaction
+** commits (WAL_SYNC_FLAGS(X)) or for checkpoint ops (CKPT_SYNC_FLAGS(X)):
+*/
+#define WAL_SYNC_FLAGS(X)   ((X)&0x03)
+#define CKPT_SYNC_FLAGS(X)  (((X)>>2)&0x03)
+
+#ifdef SQLITE_OMIT_WAL
+# define sqlite3WalOpen(x,y,z)                   0
+# define sqlite3WalLimit(x,y)
+# define sqlite3WalClose(v,w,x,y,z)              0
+# define sqlite3WalBeginReadTransaction(y,z)     0
+# define sqlite3WalEndReadTransaction(z)
+# define sqlite3WalDbsize(y)                     0
+# define sqlite3WalBeginWriteTransaction(y)      0
+# define sqlite3WalEndWriteTransaction(x)        0
+# define sqlite3WalUndo(x,y,z)                   0
+# define sqlite3WalSavepoint(y,z)
+# define sqlite3WalSavepointUndo(y,z)            0
+# define sqlite3WalFrames(u,v,w,x,y,z)           0
+# define sqlite3WalCheckpoint(q,r,s,t,u,v,w,x,y,z) 0
+# define sqlite3WalCallback(z)                   0
+# define sqlite3WalExclusiveMode(y,z)            0
+# define sqlite3WalHeapMemory(z)                 0
+# define sqlite3WalFramesize(z)                  0
+# define sqlite3WalFindFrame(x,y,z)              0
+# define sqlite3WalFile(x)                       0
+# undef SQLITE_USE_SEH
+#else
+
+#define WAL_SAVEPOINT_NDATA 4
+
+/* Connection to a write-ahead log (WAL) file.
+** There is one object of this type for each pager.
+*/
+typedef struct Wal Wal;
+
+/* Open and close a connection to a write-ahead log. */
+SQLITE_PRIVATE int sqlite3WalOpen(sqlite3_vfs*, sqlite3_file*, const char *, int, i64, Wal**);
+SQLITE_PRIVATE int sqlite3WalClose(Wal *pWal, sqlite3*, int sync_flags, int, u8 *);
+
+/* Set the limiting size of a WAL file. */
+SQLITE_PRIVATE void sqlite3WalLimit(Wal*, i64);
+
+/* Used by readers to open (lock) and close (unlock) a snapshot.  A
+** snapshot is like a read-transaction.  It is the state of the database
+** at an instant in time.  sqlite3WalOpenSnapshot gets a read lock and
+** preserves the current state even if the other threads or processes
+** write to or checkpoint the WAL.  sqlite3WalCloseSnapshot() closes the
+** transaction and releases the lock.
+*/
+SQLITE_PRIVATE int sqlite3WalBeginReadTransaction(Wal *pWal, int *);
+SQLITE_PRIVATE void sqlite3WalEndReadTransaction(Wal *pWal);
+
+/* Read a page from the write-ahead log, if it is present. */
+SQLITE_PRIVATE int sqlite3WalFindFrame(Wal *, Pgno, u32 *);
+SQLITE_PRIVATE int sqlite3WalReadFrame(Wal *, u32, int, u8 *);
+
+/* If the WAL is not empty, return the size of the database. */
+SQLITE_PRIVATE Pgno sqlite3WalDbsize(Wal *pWal);
+
+/* Obtain or release the WRITER lock. */
+SQLITE_PRIVATE int sqlite3WalBeginWriteTransaction(Wal *pWal);
+SQLITE_PRIVATE int sqlite3WalEndWriteTransaction(Wal *pWal);
+
+/* Undo any frames written (but not committed) to the log */
+SQLITE_PRIVATE int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx);
+
+/* Return an integer that records the current (uncommitted) write
+** position in the WAL */
+SQLITE_PRIVATE void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData);
+
+/* Move the write position of the WAL back to iFrame.  Called in
+** response to a ROLLBACK TO command. */
+SQLITE_PRIVATE int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData);
+
+/* Write a frame or frames to the log. */
+SQLITE_PRIVATE int sqlite3WalFrames(Wal *pWal, int, PgHdr *, Pgno, int, int);
+
+/* Copy pages from the log to the database file */
+SQLITE_PRIVATE int sqlite3WalCheckpoint(
+  Wal *pWal,                      /* Write-ahead log connection */
+  sqlite3 *db,                    /* Check this handle's interrupt flag */
+  int eMode,                      /* One of PASSIVE, FULL and RESTART */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags to sync db file with (or 0) */
+  int nBuf,                       /* Size of buffer nBuf */
+  u8 *zBuf,                       /* Temporary buffer to use */
+  int *pnLog,                     /* OUT: Number of frames in WAL */
+  int *pnCkpt                     /* OUT: Number of backfilled frames in WAL */
+);
+
+/* Return the value to pass to a sqlite3_wal_hook callback, the
+** number of frames in the WAL at the point of the last commit since
+** sqlite3WalCallback() was called.  If no commits have occurred since
+** the last call, then return 0.
+*/
+SQLITE_PRIVATE int sqlite3WalCallback(Wal *pWal);
+
+/* Tell the wal layer that an EXCLUSIVE lock has been obtained (or released)
+** by the pager layer on the database file.
+*/
+SQLITE_PRIVATE int sqlite3WalExclusiveMode(Wal *pWal, int op);
+
+/* Return true if the argument is non-NULL and the WAL module is using
+** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
+** WAL module is using shared-memory, return false.
+*/
+SQLITE_PRIVATE int sqlite3WalHeapMemory(Wal *pWal);
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+SQLITE_PRIVATE int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot);
+SQLITE_PRIVATE void sqlite3WalSnapshotOpen(Wal *pWal, sqlite3_snapshot *pSnapshot);
+SQLITE_PRIVATE int sqlite3WalSnapshotRecover(Wal *pWal);
+SQLITE_PRIVATE int sqlite3WalSnapshotCheck(Wal *pWal, sqlite3_snapshot *pSnapshot);
+SQLITE_PRIVATE void sqlite3WalSnapshotUnlock(Wal *pWal);
+#endif
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/* If the WAL file is not empty, return the number of bytes of content
+** stored in each frame (i.e. the db page-size when the WAL was created).
+*/
+SQLITE_PRIVATE int sqlite3WalFramesize(Wal *pWal);
+#endif
+
+/* Return the sqlite3_file object for the WAL file */
+SQLITE_PRIVATE sqlite3_file *sqlite3WalFile(Wal *pWal);
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+SQLITE_PRIVATE int sqlite3WalWriteLock(Wal *pWal, int bLock);
+SQLITE_PRIVATE void sqlite3WalDb(Wal *pWal, sqlite3 *db);
+#endif
+
+#ifdef SQLITE_USE_SEH
+SQLITE_PRIVATE int sqlite3WalSystemErrno(Wal*);
+#endif
+
+#endif /* ifndef SQLITE_OMIT_WAL */
+#endif /* SQLITE_WAL_H */
+
+/************** End of wal.h *************************************************/
+/************** Continuing where we left off in pager.c **********************/
+
+
+/******************* NOTES ON THE DESIGN OF THE PAGER ************************
+**
+** This comment block describes invariants that hold when using a rollback
+** journal.  These invariants do not apply for journal_mode=WAL,
+** journal_mode=MEMORY, or journal_mode=OFF.
+**
+** Within this comment block, a page is deemed to have been synced
+** automatically as soon as it is written when PRAGMA synchronous=OFF.
+** Otherwise, the page is not synced until the xSync method of the VFS
+** is called successfully on the file containing the page.
+**
+** Definition:  A page of the database file is said to be "overwriteable" if
+** one or more of the following are true about the page:
+**
+**     (a)  The original content of the page as it was at the beginning of
+**          the transaction has been written into the rollback journal and
+**          synced.
+**
+**     (b)  The page was a freelist leaf page at the start of the transaction.
+**
+**     (c)  The page number is greater than the largest page that existed in
+**          the database file at the start of the transaction.
+**
+** (1) A page of the database file is never overwritten unless one of the
+**     following are true:
+**
+**     (a) The page and all other pages on the same sector are overwriteable.
+**
+**     (b) The atomic page write optimization is enabled, and the entire
+**         transaction other than the update of the transaction sequence
+**         number consists of a single page change.
+**
+** (2) The content of a page written into the rollback journal exactly matches
+**     both the content in the database when the rollback journal was written
+**     and the content in the database at the beginning of the current
+**     transaction.
+**
+** (3) Writes to the database file are an integer multiple of the page size
+**     in length and are aligned on a page boundary.
+**
+** (4) Reads from the database file are either aligned on a page boundary and
+**     an integer multiple of the page size in length or are taken from the
+**     first 100 bytes of the database file.
+**
+** (5) All writes to the database file are synced prior to the rollback journal
+**     being deleted, truncated, or zeroed.
+**
+** (6) If a super-journal file is used, then all writes to the database file
+**     are synced prior to the super-journal being deleted.
+**
+** Definition: Two databases (or the same database at two points it time)
+** are said to be "logically equivalent" if they give the same answer to
+** all queries.  Note in particular the content of freelist leaf
+** pages can be changed arbitrarily without affecting the logical equivalence
+** of the database.
+**
+** (7) At any time, if any subset, including the empty set and the total set,
+**     of the unsynced changes to a rollback journal are removed and the
+**     journal is rolled back, the resulting database file will be logically
+**     equivalent to the database file at the beginning of the transaction.
+**
+** (8) When a transaction is rolled back, the xTruncate method of the VFS
+**     is called to restore the database file to the same size it was at
+**     the beginning of the transaction.  (In some VFSes, the xTruncate
+**     method is a no-op, but that does not change the fact the SQLite will
+**     invoke it.)
+**
+** (9) Whenever the database file is modified, at least one bit in the range
+**     of bytes from 24 through 39 inclusive will be changed prior to releasing
+**     the EXCLUSIVE lock, thus signaling other connections on the same
+**     database to flush their caches.
+**
+** (10) The pattern of bits in bytes 24 through 39 shall not repeat in less
+**      than one billion transactions.
+**
+** (11) A database file is well-formed at the beginning and at the conclusion
+**      of every transaction.
+**
+** (12) An EXCLUSIVE lock is held on the database file when writing to
+**      the database file.
+**
+** (13) A SHARED lock is held on the database file while reading any
+**      content out of the database file.
+**
+******************************************************************************/
+
+/*
+** Macros for troubleshooting.  Normally turned off
+*/
+#if 0
+int sqlite3PagerTrace=1;  /* True to enable tracing */
+#define sqlite3DebugPrintf printf
+#define PAGERTRACE(X)     if( sqlite3PagerTrace ){ sqlite3DebugPrintf X; }
+#else
+#define PAGERTRACE(X)
+#endif
+
+/*
+** The following two macros are used within the PAGERTRACE() macros above
+** to print out file-descriptors.
+**
+** PAGERID() takes a pointer to a Pager struct as its argument. The
+** associated file-descriptor is returned. FILEHANDLEID() takes an sqlite3_file
+** struct as its argument.
+*/
+#define PAGERID(p) (SQLITE_PTR_TO_INT(p->fd))
+#define FILEHANDLEID(fd) (SQLITE_PTR_TO_INT(fd))
+
+/*
+** The Pager.eState variable stores the current 'state' of a pager. A
+** pager may be in any one of the seven states shown in the following
+** state diagram.
+**
+**                            OPEN <------+------+
+**                              |         |      |
+**                              V         |      |
+**               +---------> READER-------+      |
+**               |              |                |
+**               |              V                |
+**               |<-------WRITER_LOCKED------> ERROR
+**               |              |                ^
+**               |              V                |
+**               |<------WRITER_CACHEMOD-------->|
+**               |              |                |
+**               |              V                |
+**               |<-------WRITER_DBMOD---------->|
+**               |              |                |
+**               |              V                |
+**               +<------WRITER_FINISHED-------->+
+**
+**
+** List of state transitions and the C [function] that performs each:
+**
+**   OPEN              -> READER              [sqlite3PagerSharedLock]
+**   READER            -> OPEN                [pager_unlock]
+**
+**   READER            -> WRITER_LOCKED       [sqlite3PagerBegin]
+**   WRITER_LOCKED     -> WRITER_CACHEMOD     [pager_open_journal]
+**   WRITER_CACHEMOD   -> WRITER_DBMOD        [syncJournal]
+**   WRITER_DBMOD      -> WRITER_FINISHED     [sqlite3PagerCommitPhaseOne]
+**   WRITER_***        -> READER              [pager_end_transaction]
+**
+**   WRITER_***        -> ERROR               [pager_error]
+**   ERROR             -> OPEN                [pager_unlock]
+**
+**
+**  OPEN:
+**
+**    The pager starts up in this state. Nothing is guaranteed in this
+**    state - the file may or may not be locked and the database size is
+**    unknown. The database may not be read or written.
+**
+**    * No read or write transaction is active.
+**    * Any lock, or no lock at all, may be held on the database file.
+**    * The dbSize, dbOrigSize and dbFileSize variables may not be trusted.
+**
+**  READER:
+**
+**    In this state all the requirements for reading the database in
+**    rollback (non-WAL) mode are met. Unless the pager is (or recently
+**    was) in exclusive-locking mode, a user-level read transaction is
+**    open. The database size is known in this state.
+**
+**    A connection running with locking_mode=normal enters this state when
+**    it opens a read-transaction on the database and returns to state
+**    OPEN after the read-transaction is completed. However a connection
+**    running in locking_mode=exclusive (including temp databases) remains in
+**    this state even after the read-transaction is closed. The only way
+**    a locking_mode=exclusive connection can transition from READER to OPEN
+**    is via the ERROR state (see below).
+**
+**    * A read transaction may be active (but a write-transaction cannot).
+**    * A SHARED or greater lock is held on the database file.
+**    * The dbSize variable may be trusted (even if a user-level read
+**      transaction is not active). The dbOrigSize and dbFileSize variables
+**      may not be trusted at this point.
+**    * If the database is a WAL database, then the WAL connection is open.
+**    * Even if a read-transaction is not open, it is guaranteed that
+**      there is no hot-journal in the file-system.
+**
+**  WRITER_LOCKED:
+**
+**    The pager moves to this state from READER when a write-transaction
+**    is first opened on the database. In WRITER_LOCKED state, all locks
+**    required to start a write-transaction are held, but no actual
+**    modifications to the cache or database have taken place.
+**
+**    In rollback mode, a RESERVED or (if the transaction was opened with
+**    BEGIN EXCLUSIVE) EXCLUSIVE lock is obtained on the database file when
+**    moving to this state, but the journal file is not written to or opened
+**    to in this state. If the transaction is committed or rolled back while
+**    in WRITER_LOCKED state, all that is required is to unlock the database
+**    file.
+**
+**    IN WAL mode, WalBeginWriteTransaction() is called to lock the log file.
+**    If the connection is running with locking_mode=exclusive, an attempt
+**    is made to obtain an EXCLUSIVE lock on the database file.
+**
+**    * A write transaction is active.
+**    * If the connection is open in rollback-mode, a RESERVED or greater
+**      lock is held on the database file.
+**    * If the connection is open in WAL-mode, a WAL write transaction
+**      is open (i.e. sqlite3WalBeginWriteTransaction() has been successfully
+**      called).
+**    * The dbSize, dbOrigSize and dbFileSize variables are all valid.
+**    * The contents of the pager cache have not been modified.
+**    * The journal file may or may not be open.
+**    * Nothing (not even the first header) has been written to the journal.
+**
+**  WRITER_CACHEMOD:
+**
+**    A pager moves from WRITER_LOCKED state to this state when a page is
+**    first modified by the upper layer. In rollback mode the journal file
+**    is opened (if it is not already open) and a header written to the
+**    start of it. The database file on disk has not been modified.
+**
+**    * A write transaction is active.
+**    * A RESERVED or greater lock is held on the database file.
+**    * The journal file is open and the first header has been written
+**      to it, but the header has not been synced to disk.
+**    * The contents of the page cache have been modified.
+**
+**  WRITER_DBMOD:
+**
+**    The pager transitions from WRITER_CACHEMOD into WRITER_DBMOD state
+**    when it modifies the contents of the database file. WAL connections
+**    never enter this state (since they do not modify the database file,
+**    just the log file).
+**
+**    * A write transaction is active.
+**    * An EXCLUSIVE or greater lock is held on the database file.
+**    * The journal file is open and the first header has been written
+**      and synced to disk.
+**    * The contents of the page cache have been modified (and possibly
+**      written to disk).
+**
+**  WRITER_FINISHED:
+**
+**    It is not possible for a WAL connection to enter this state.
+**
+**    A rollback-mode pager changes to WRITER_FINISHED state from WRITER_DBMOD
+**    state after the entire transaction has been successfully written into the
+**    database file. In this state the transaction may be committed simply
+**    by finalizing the journal file. Once in WRITER_FINISHED state, it is
+**    not possible to modify the database further. At this point, the upper
+**    layer must either commit or rollback the transaction.
+**
+**    * A write transaction is active.
+**    * An EXCLUSIVE or greater lock is held on the database file.
+**    * All writing and syncing of journal and database data has finished.
+**      If no error occurred, all that remains is to finalize the journal to
+**      commit the transaction. If an error did occur, the caller will need
+**      to rollback the transaction.
+**
+**  ERROR:
+**
+**    The ERROR state is entered when an IO or disk-full error (including
+**    SQLITE_IOERR_NOMEM) occurs at a point in the code that makes it
+**    difficult to be sure that the in-memory pager state (cache contents,
+**    db size etc.) are consistent with the contents of the file-system.
+**
+**    Temporary pager files may enter the ERROR state, but in-memory pagers
+**    cannot.
+**
+**    For example, if an IO error occurs while performing a rollback,
+**    the contents of the page-cache may be left in an inconsistent state.
+**    At this point it would be dangerous to change back to READER state
+**    (as usually happens after a rollback). Any subsequent readers might
+**    report database corruption (due to the inconsistent cache), and if
+**    they upgrade to writers, they may inadvertently corrupt the database
+**    file. To avoid this hazard, the pager switches into the ERROR state
+**    instead of READER following such an error.
+**
+**    Once it has entered the ERROR state, any attempt to use the pager
+**    to read or write data returns an error. Eventually, once all
+**    outstanding transactions have been abandoned, the pager is able to
+**    transition back to OPEN state, discarding the contents of the
+**    page-cache and any other in-memory state at the same time. Everything
+**    is reloaded from disk (and, if necessary, hot-journal rollback performed)
+**    when a read-transaction is next opened on the pager (transitioning
+**    the pager into READER state). At that point the system has recovered
+**    from the error.
+**
+**    Specifically, the pager jumps into the ERROR state if:
+**
+**      1. An error occurs while attempting a rollback. This happens in
+**         function sqlite3PagerRollback().
+**
+**      2. An error occurs while attempting to finalize a journal file
+**         following a commit in function sqlite3PagerCommitPhaseTwo().
+**
+**      3. An error occurs while attempting to write to the journal or
+**         database file in function pagerStress() in order to free up
+**         memory.
+**
+**    In other cases, the error is returned to the b-tree layer. The b-tree
+**    layer then attempts a rollback operation. If the error condition
+**    persists, the pager enters the ERROR state via condition (1) above.
+**
+**    Condition (3) is necessary because it can be triggered by a read-only
+**    statement executed within a transaction. In this case, if the error
+**    code were simply returned to the user, the b-tree layer would not
+**    automatically attempt a rollback, as it assumes that an error in a
+**    read-only statement cannot leave the pager in an internally inconsistent
+**    state.
+**
+**    * The Pager.errCode variable is set to something other than SQLITE_OK.
+**    * There are one or more outstanding references to pages (after the
+**      last reference is dropped the pager should move back to OPEN state).
+**    * The pager is not an in-memory pager.
+**
+**
+** Notes:
+**
+**   * A pager is never in WRITER_DBMOD or WRITER_FINISHED state if the
+**     connection is open in WAL mode. A WAL connection is always in one
+**     of the first four states.
+**
+**   * Normally, a connection open in exclusive mode is never in PAGER_OPEN
+**     state. There are two exceptions: immediately after exclusive-mode has
+**     been turned on (and before any read or write transactions are
+**     executed), and when the pager is leaving the "error state".
+**
+**   * See also: assert_pager_state().
+*/
+#define PAGER_OPEN                  0
+#define PAGER_READER                1
+#define PAGER_WRITER_LOCKED         2
+#define PAGER_WRITER_CACHEMOD       3
+#define PAGER_WRITER_DBMOD          4
+#define PAGER_WRITER_FINISHED       5
+#define PAGER_ERROR                 6
+
+/*
+** The Pager.eLock variable is almost always set to one of the
+** following locking-states, according to the lock currently held on
+** the database file: NO_LOCK, SHARED_LOCK, RESERVED_LOCK or EXCLUSIVE_LOCK.
+** This variable is kept up to date as locks are taken and released by
+** the pagerLockDb() and pagerUnlockDb() wrappers.
+**
+** If the VFS xLock() or xUnlock() returns an error other than SQLITE_BUSY
+** (i.e. one of the SQLITE_IOERR subtypes), it is not clear whether or not
+** the operation was successful. In these circumstances pagerLockDb() and
+** pagerUnlockDb() take a conservative approach - eLock is always updated
+** when unlocking the file, and only updated when locking the file if the
+** VFS call is successful. This way, the Pager.eLock variable may be set
+** to a less exclusive (lower) value than the lock that is actually held
+** at the system level, but it is never set to a more exclusive value.
+**
+** This is usually safe. If an xUnlock fails or appears to fail, there may
+** be a few redundant xLock() calls or a lock may be held for longer than
+** required, but nothing really goes wrong.
+**
+** The exception is when the database file is unlocked as the pager moves
+** from ERROR to OPEN state. At this point there may be a hot-journal file
+** in the file-system that needs to be rolled back (as part of an OPEN->SHARED
+** transition, by the same pager or any other). If the call to xUnlock()
+** fails at this point and the pager is left holding an EXCLUSIVE lock, this
+** can confuse the call to xCheckReservedLock() call made later as part
+** of hot-journal detection.
+**
+** xCheckReservedLock() is defined as returning true "if there is a RESERVED
+** lock held by this process or any others". So xCheckReservedLock may
+** return true because the caller itself is holding an EXCLUSIVE lock (but
+** doesn't know it because of a previous error in xUnlock). If this happens
+** a hot-journal may be mistaken for a journal being created by an active
+** transaction in another process, causing SQLite to read from the database
+** without rolling it back.
+**
+** To work around this, if a call to xUnlock() fails when unlocking the
+** database in the ERROR state, Pager.eLock is set to UNKNOWN_LOCK. It
+** is only changed back to a real locking state after a successful call
+** to xLock(EXCLUSIVE). Also, the code to do the OPEN->SHARED state transition
+** omits the check for a hot-journal if Pager.eLock is set to UNKNOWN_LOCK
+** lock. Instead, it assumes a hot-journal exists and obtains an EXCLUSIVE
+** lock on the database file before attempting to roll it back. See function
+** PagerSharedLock() for more detail.
+**
+** Pager.eLock may only be set to UNKNOWN_LOCK when the pager is in
+** PAGER_OPEN state.
+*/
+#define UNKNOWN_LOCK                (EXCLUSIVE_LOCK+1)
+
+/*
+** The maximum allowed sector size. 64KiB. If the xSectorsize() method
+** returns a value larger than this, then MAX_SECTOR_SIZE is used instead.
+** This could conceivably cause corruption following a power failure on
+** such a system. This is currently an undocumented limit.
+*/
+#define MAX_SECTOR_SIZE 0x10000
+
+
+/*
+** An instance of the following structure is allocated for each active
+** savepoint and statement transaction in the system. All such structures
+** are stored in the Pager.aSavepoint[] array, which is allocated and
+** resized using sqlite3Realloc().
+**
+** When a savepoint is created, the PagerSavepoint.iHdrOffset field is
+** set to 0. If a journal-header is written into the main journal while
+** the savepoint is active, then iHdrOffset is set to the byte offset
+** immediately following the last journal record written into the main
+** journal before the journal-header. This is required during savepoint
+** rollback (see pagerPlaybackSavepoint()).
+*/
+typedef struct PagerSavepoint PagerSavepoint;
+struct PagerSavepoint {
+  i64 iOffset;                 /* Starting offset in main journal */
+  i64 iHdrOffset;              /* See above */
+  Bitvec *pInSavepoint;        /* Set of pages in this savepoint */
+  Pgno nOrig;                  /* Original number of pages in file */
+  Pgno iSubRec;                /* Index of first record in sub-journal */
+  int bTruncateOnRelease;      /* If stmt journal may be truncated on RELEASE */
+#ifndef SQLITE_OMIT_WAL
+  u32 aWalData[WAL_SAVEPOINT_NDATA];        /* WAL savepoint context */
+#endif
+};
+
+/*
+** Bits of the Pager.doNotSpill flag.  See further description below.
+*/
+#define SPILLFLAG_OFF         0x01 /* Never spill cache.  Set via pragma */
+#define SPILLFLAG_ROLLBACK    0x02 /* Current rolling back, so do not spill */
+#define SPILLFLAG_NOSYNC      0x04 /* Spill is ok, but do not sync */
+
+/*
+** An open page cache is an instance of struct Pager. A description of
+** some of the more important member variables follows:
+**
+** eState
+**
+**   The current 'state' of the pager object. See the comment and state
+**   diagram above for a description of the pager state.
+**
+** eLock
+**
+**   For a real on-disk database, the current lock held on the database file -
+**   NO_LOCK, SHARED_LOCK, RESERVED_LOCK or EXCLUSIVE_LOCK.
+**
+**   For a temporary or in-memory database (neither of which require any
+**   locks), this variable is always set to EXCLUSIVE_LOCK. Since such
+**   databases always have Pager.exclusiveMode==1, this tricks the pager
+**   logic into thinking that it already has all the locks it will ever
+**   need (and no reason to release them).
+**
+**   In some (obscure) circumstances, this variable may also be set to
+**   UNKNOWN_LOCK. See the comment above the #define of UNKNOWN_LOCK for
+**   details.
+**
+** changeCountDone
+**
+**   This boolean variable is used to make sure that the change-counter
+**   (the 4-byte header field at byte offset 24 of the database file) is
+**   not updated more often than necessary.
+**
+**   It is set to true when the change-counter field is updated, which
+**   can only happen if an exclusive lock is held on the database file.
+**   It is cleared (set to false) whenever an exclusive lock is
+**   relinquished on the database file. Each time a transaction is committed,
+**   The changeCountDone flag is inspected. If it is true, the work of
+**   updating the change-counter is omitted for the current transaction.
+**
+**   This mechanism means that when running in exclusive mode, a connection
+**   need only update the change-counter once, for the first transaction
+**   committed.
+**
+** setSuper
+**
+**   When PagerCommitPhaseOne() is called to commit a transaction, it may
+**   (or may not) specify a super-journal name to be written into the
+**   journal file before it is synced to disk.
+**
+**   Whether or not a journal file contains a super-journal pointer affects
+**   the way in which the journal file is finalized after the transaction is
+**   committed or rolled back when running in "journal_mode=PERSIST" mode.
+**   If a journal file does not contain a super-journal pointer, it is
+**   finalized by overwriting the first journal header with zeroes. If
+**   it does contain a super-journal pointer the journal file is finalized
+**   by truncating it to zero bytes, just as if the connection were
+**   running in "journal_mode=truncate" mode.
+**
+**   Journal files that contain super-journal pointers cannot be finalized
+**   simply by overwriting the first journal-header with zeroes, as the
+**   super-journal pointer could interfere with hot-journal rollback of any
+**   subsequently interrupted transaction that reuses the journal file.
+**
+**   The flag is cleared as soon as the journal file is finalized (either
+**   by PagerCommitPhaseTwo or PagerRollback). If an IO error prevents the
+**   journal file from being successfully finalized, the setSuper flag
+**   is cleared anyway (and the pager will move to ERROR state).
+**
+** doNotSpill
+**
+**   This variables control the behavior of cache-spills  (calls made by
+**   the pcache module to the pagerStress() routine to write cached data
+**   to the file-system in order to free up memory).
+**
+**   When bits SPILLFLAG_OFF or SPILLFLAG_ROLLBACK of doNotSpill are set,
+**   writing to the database from pagerStress() is disabled altogether.
+**   The SPILLFLAG_ROLLBACK case is done in a very obscure case that
+**   comes up during savepoint rollback that requires the pcache module
+**   to allocate a new page to prevent the journal file from being written
+**   while it is being traversed by code in pager_playback().  The SPILLFLAG_OFF
+**   case is a user preference.
+**
+**   If the SPILLFLAG_NOSYNC bit is set, writing to the database from
+**   pagerStress() is permitted, but syncing the journal file is not.
+**   This flag is set by sqlite3PagerWrite() when the file-system sector-size
+**   is larger than the database page-size in order to prevent a journal sync
+**   from happening in between the journalling of two pages on the same sector.
+**
+** subjInMemory
+**
+**   This is a boolean variable. If true, then any required sub-journal
+**   is opened as an in-memory journal file. If false, then in-memory
+**   sub-journals are only used for in-memory pager files.
+**
+**   This variable is updated by the upper layer each time a new
+**   write-transaction is opened.
+**
+** dbSize, dbOrigSize, dbFileSize
+**
+**   Variable dbSize is set to the number of pages in the database file.
+**   It is valid in PAGER_READER and higher states (all states except for
+**   OPEN and ERROR).
+**
+**   dbSize is set based on the size of the database file, which may be
+**   larger than the size of the database (the value stored at offset
+**   28 of the database header by the btree). If the size of the file
+**   is not an integer multiple of the page-size, the value stored in
+**   dbSize is rounded down (i.e. a 5KB file with 2K page-size has dbSize==2).
+**   Except, any file that is greater than 0 bytes in size is considered
+**   to have at least one page. (i.e. a 1KB file with 2K page-size leads
+**   to dbSize==1).
+**
+**   During a write-transaction, if pages with page-numbers greater than
+**   dbSize are modified in the cache, dbSize is updated accordingly.
+**   Similarly, if the database is truncated using PagerTruncateImage(),
+**   dbSize is updated.
+**
+**   Variables dbOrigSize and dbFileSize are valid in states
+**   PAGER_WRITER_LOCKED and higher. dbOrigSize is a copy of the dbSize
+**   variable at the start of the transaction. It is used during rollback,
+**   and to determine whether or not pages need to be journalled before
+**   being modified.
+**
+**   Throughout a write-transaction, dbFileSize contains the size of
+**   the file on disk in pages. It is set to a copy of dbSize when the
+**   write-transaction is first opened, and updated when VFS calls are made
+**   to write or truncate the database file on disk.
+**
+**   The only reason the dbFileSize variable is required is to suppress
+**   unnecessary calls to xTruncate() after committing a transaction. If,
+**   when a transaction is committed, the dbFileSize variable indicates
+**   that the database file is larger than the database image (Pager.dbSize),
+**   pager_truncate() is called. The pager_truncate() call uses xFilesize()
+**   to measure the database file on disk, and then truncates it if required.
+**   dbFileSize is not used when rolling back a transaction. In this case
+**   pager_truncate() is called unconditionally (which means there may be
+**   a call to xFilesize() that is not strictly required). In either case,
+**   pager_truncate() may cause the file to become smaller or larger.
+**
+** dbHintSize
+**
+**   The dbHintSize variable is used to limit the number of calls made to
+**   the VFS xFileControl(FCNTL_SIZE_HINT) method.
+**
+**   dbHintSize is set to a copy of the dbSize variable when a
+**   write-transaction is opened (at the same time as dbFileSize and
+**   dbOrigSize). If the xFileControl(FCNTL_SIZE_HINT) method is called,
+**   dbHintSize is increased to the number of pages that correspond to the
+**   size-hint passed to the method call. See pager_write_pagelist() for
+**   details.
+**
+** errCode
+**
+**   The Pager.errCode variable is only ever used in PAGER_ERROR state. It
+**   is set to zero in all other states. In PAGER_ERROR state, Pager.errCode
+**   is always set to SQLITE_FULL, SQLITE_IOERR or one of the SQLITE_IOERR_XXX
+**   sub-codes.
+**
+** syncFlags, walSyncFlags
+**
+**   syncFlags is either SQLITE_SYNC_NORMAL (0x02) or SQLITE_SYNC_FULL (0x03).
+**   syncFlags is used for rollback mode.  walSyncFlags is used for WAL mode
+**   and contains the flags used to sync the checkpoint operations in the
+**   lower two bits, and sync flags used for transaction commits in the WAL
+**   file in bits 0x04 and 0x08.  In other words, to get the correct sync flags
+**   for checkpoint operations, use (walSyncFlags&0x03) and to get the correct
+**   sync flags for transaction commit, use ((walSyncFlags>>2)&0x03).  Note
+**   that with synchronous=NORMAL in WAL mode, transaction commit is not synced
+**   meaning that the 0x04 and 0x08 bits are both zero.
+*/
+struct Pager {
+  sqlite3_vfs *pVfs;          /* OS functions to use for IO */
+  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
+  u8 journalMode;             /* One of the PAGER_JOURNALMODE_* values */
+  u8 useJournal;              /* Use a rollback journal on this file */
+  u8 noSync;                  /* Do not sync the journal if true */
+  u8 fullSync;                /* Do extra syncs of the journal for robustness */
+  u8 extraSync;               /* sync directory after journal delete */
+  u8 syncFlags;               /* SYNC_NORMAL or SYNC_FULL otherwise */
+  u8 walSyncFlags;            /* See description above */
+  u8 tempFile;                /* zFilename is a temporary or immutable file */
+  u8 noLock;                  /* Do not lock (except in WAL mode) */
+  u8 readOnly;                /* True for a read-only database */
+  u8 memDb;                   /* True to inhibit all file I/O */
+  u8 memVfs;                  /* VFS-implemented memory database */
+
+  /**************************************************************************
+  ** The following block contains those class members that change during
+  ** routine operation.  Class members not in this block are either fixed
+  ** when the pager is first created or else only change when there is a
+  ** significant mode change (such as changing the page_size, locking_mode,
+  ** or the journal_mode).  From another view, these class members describe
+  ** the "state" of the pager, while other class members describe the
+  ** "configuration" of the pager.
+  */
+  u8 eState;                  /* Pager state (OPEN, READER, WRITER_LOCKED..) */
+  u8 eLock;                   /* Current lock held on database file */
+  u8 changeCountDone;         /* Set after incrementing the change-counter */
+  u8 setSuper;                /* Super-jrnl name is written into jrnl */
+  u8 doNotSpill;              /* Do not spill the cache when non-zero */
+  u8 subjInMemory;            /* True to use in-memory sub-journals */
+  u8 bUseFetch;               /* True to use xFetch() */
+  u8 hasHeldSharedLock;       /* True if a shared lock has ever been held */
+  Pgno dbSize;                /* Number of pages in the database */
+  Pgno dbOrigSize;            /* dbSize before the current transaction */
+  Pgno dbFileSize;            /* Number of pages in the database file */
+  Pgno dbHintSize;            /* Value passed to FCNTL_SIZE_HINT call */
+  int errCode;                /* One of several kinds of errors */
+  int nRec;                   /* Pages journalled since last j-header written */
+  u32 cksumInit;              /* Quasi-random value added to every checksum */
+  u32 nSubRec;                /* Number of records written to sub-journal */
+  Bitvec *pInJournal;         /* One bit for each page in the database file */
+  sqlite3_file *fd;           /* File descriptor for database */
+  sqlite3_file *jfd;          /* File descriptor for main journal */
+  sqlite3_file *sjfd;         /* File descriptor for sub-journal */
+  i64 journalOff;             /* Current write offset in the journal file */
+  i64 journalHdr;             /* Byte offset to previous journal header */
+  sqlite3_backup *pBackup;    /* Pointer to list of ongoing backup processes */
+  PagerSavepoint *aSavepoint; /* Array of active savepoints */
+  int nSavepoint;             /* Number of elements in aSavepoint[] */
+  u32 iDataVersion;           /* Changes whenever database content changes */
+  char dbFileVers[16];        /* Changes whenever database file changes */
+
+  int nMmapOut;               /* Number of mmap pages currently outstanding */
+  sqlite3_int64 szMmap;       /* Desired maximum mmap size */
+  PgHdr *pMmapFreelist;       /* List of free mmap page headers (pDirty) */
+  /*
+  ** End of the routinely-changing class members
+  ***************************************************************************/
+
+  u16 nExtra;                 /* Add this many bytes to each in-memory page */
+  i16 nReserve;               /* Number of unused bytes at end of each page */
+  u32 vfsFlags;               /* Flags for sqlite3_vfs.xOpen() */
+  u32 sectorSize;             /* Assumed sector size during rollback */
+  Pgno mxPgno;                /* Maximum allowed size of the database */
+  Pgno lckPgno;               /* Page number for the locking page */
+  i64 pageSize;               /* Number of bytes in a page */
+  i64 journalSizeLimit;       /* Size limit for persistent journal files */
+  char *zFilename;            /* Name of the database file */
+  char *zJournal;             /* Name of the journal file */
+  int (*xBusyHandler)(void*); /* Function to call when busy */
+  void *pBusyHandlerArg;      /* Context argument for xBusyHandler */
+  u32 aStat[4];               /* Total cache hits, misses, writes, spills */
+#ifdef SQLITE_TEST
+  int nRead;                  /* Database pages read */
+#endif
+  void (*xReiniter)(DbPage*); /* Call this routine when reloading pages */
+  int (*xGet)(Pager*,Pgno,DbPage**,int); /* Routine to fetch a patch */
+  char *pTmpSpace;            /* Pager.pageSize bytes of space for tmp use */
+  PCache *pPCache;            /* Pointer to page cache object */
+#ifndef SQLITE_OMIT_WAL
+  Wal *pWal;                  /* Write-ahead log used by "journal_mode=wal" */
+  char *zWal;                 /* File name for write-ahead log */
+#endif
+};
+
+/*
+** Indexes for use with Pager.aStat[]. The Pager.aStat[] array contains
+** the values accessed by passing SQLITE_DBSTATUS_CACHE_HIT, CACHE_MISS
+** or CACHE_WRITE to sqlite3_db_status().
+*/
+#define PAGER_STAT_HIT   0
+#define PAGER_STAT_MISS  1
+#define PAGER_STAT_WRITE 2
+#define PAGER_STAT_SPILL 3
+
+/*
+** The following global variables hold counters used for
+** testing purposes only.  These variables do not exist in
+** a non-testing build.  These variables are not thread-safe.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_pager_readdb_count = 0;    /* Number of full pages read from DB */
+SQLITE_API int sqlite3_pager_writedb_count = 0;   /* Number of full pages written to DB */
+SQLITE_API int sqlite3_pager_writej_count = 0;    /* Number of pages written to journal */
+# define PAGER_INCR(v)  v++
+#else
+# define PAGER_INCR(v)
+#endif
+
+
+
+/*
+** Journal files begin with the following magic string.  The data
+** was obtained from /dev/random.  It is used only as a sanity check.
+**
+** Since version 2.8.0, the journal format contains additional sanity
+** checking information.  If the power fails while the journal is being
+** written, semi-random garbage data might appear in the journal
+** file after power is restored.  If an attempt is then made
+** to roll the journal back, the database could be corrupted.  The additional
+** sanity checking data is an attempt to discover the garbage in the
+** journal and ignore it.
+**
+** The sanity checking information for the new journal format consists
+** of a 32-bit checksum on each page of data.  The checksum covers both
+** the page number and the pPager->pageSize bytes of data for the page.
+** This cksum is initialized to a 32-bit random value that appears in the
+** journal file right after the header.  The random initializer is important,
+** because garbage data that appears at the end of a journal is likely
+** data that was once in other files that have now been deleted.  If the
+** garbage data came from an obsolete journal file, the checksums might
+** be correct.  But by initializing the checksum to random value which
+** is different for every journal, we minimize that risk.
+*/
+static const unsigned char aJournalMagic[] = {
+  0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7,
+};
+
+/*
+** The size of the of each page record in the journal is given by
+** the following macro.
+*/
+#define JOURNAL_PG_SZ(pPager)  ((pPager->pageSize) + 8)
+
+/*
+** The journal header size for this pager. This is usually the same
+** size as a single disk sector. See also setSectorSize().
+*/
+#define JOURNAL_HDR_SZ(pPager) (pPager->sectorSize)
+
+/*
+** The macro MEMDB is true if we are dealing with an in-memory database.
+** We do this as a macro so that if the SQLITE_OMIT_MEMORYDB macro is set,
+** the value of MEMDB will be a constant and the compiler will optimize
+** out code that would never execute.
+*/
+#ifdef SQLITE_OMIT_MEMORYDB
+# define MEMDB 0
+#else
+# define MEMDB pPager->memDb
+#endif
+
+/*
+** The macro USEFETCH is true if we are allowed to use the xFetch and xUnfetch
+** interfaces to access the database using memory-mapped I/O.
+*/
+#if SQLITE_MAX_MMAP_SIZE>0
+# define USEFETCH(x) ((x)->bUseFetch)
+#else
+# define USEFETCH(x) 0
+#endif
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+/*
+** Return true if page pgno can be read directly from the database file
+** by the b-tree layer. This is the case if:
+**
+**   (1)  the database file is open
+**   (2)  the VFS for the database is able to do unaligned sub-page reads
+**   (3)  there are no dirty pages in the cache, and
+**   (4)  the desired page is not currently in the wal file.
+*/
+SQLITE_PRIVATE int sqlite3PagerDirectReadOk(Pager *pPager, Pgno pgno){
+  assert( pPager!=0 );
+  assert( pPager->fd!=0 );
+  if( pPager->fd->pMethods==0 ) return 0;  /* Case (1) */
+  if( sqlite3PCacheIsDirty(pPager->pPCache) ) return 0; /* Failed (3) */
+#ifndef SQLITE_OMIT_WAL
+  if( pPager->pWal ){
+    u32 iRead = 0;
+    (void)sqlite3WalFindFrame(pPager->pWal, pgno, &iRead);
+    if( iRead ) return 0;  /* Case (4) */
+  }
+#endif
+  assert( pPager->fd->pMethods->xDeviceCharacteristics!=0 );
+  if( (pPager->fd->pMethods->xDeviceCharacteristics(pPager->fd)
+        & SQLITE_IOCAP_SUBPAGE_READ)==0 ){
+    return 0; /* Case (2) */
+  }
+  return 1;
+}
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+# define pagerUseWal(x) ((x)->pWal!=0)
+#else
+# define pagerUseWal(x) 0
+# define pagerRollbackWal(x) 0
+# define pagerWalFrames(v,w,x,y) 0
+# define pagerOpenWalIfPresent(z) SQLITE_OK
+# define pagerBeginReadTransaction(z) SQLITE_OK
+#endif
+
+#ifndef NDEBUG
+/*
+** Usage:
+**
+**   assert( assert_pager_state(pPager) );
+**
+** This function runs many asserts to try to find inconsistencies in
+** the internal state of the Pager object.
+*/
+static int assert_pager_state(Pager *p){
+  Pager *pPager = p;
+
+  /* State must be valid. */
+  assert( p->eState==PAGER_OPEN
+       || p->eState==PAGER_READER
+       || p->eState==PAGER_WRITER_LOCKED
+       || p->eState==PAGER_WRITER_CACHEMOD
+       || p->eState==PAGER_WRITER_DBMOD
+       || p->eState==PAGER_WRITER_FINISHED
+       || p->eState==PAGER_ERROR
+  );
+
+  /* Regardless of the current state, a temp-file connection always behaves
+  ** as if it has an exclusive lock on the database file. It never updates
+  ** the change-counter field, so the changeCountDone flag is always set.
+  */
+  assert( p->tempFile==0 || p->eLock==EXCLUSIVE_LOCK );
+  assert( p->tempFile==0 || pPager->changeCountDone );
+
+  /* If the useJournal flag is clear, the journal-mode must be "OFF".
+  ** And if the journal-mode is "OFF", the journal file must not be open.
+  */
+  assert( p->journalMode==PAGER_JOURNALMODE_OFF || p->useJournal );
+  assert( p->journalMode!=PAGER_JOURNALMODE_OFF || !isOpen(p->jfd) );
+
+  /* Check that MEMDB implies noSync. And an in-memory journal. Since
+  ** this means an in-memory pager performs no IO at all, it cannot encounter
+  ** either SQLITE_IOERR or SQLITE_FULL during rollback or while finalizing
+  ** a journal file. (although the in-memory journal implementation may
+  ** return SQLITE_IOERR_NOMEM while the journal file is being written). It
+  ** is therefore not possible for an in-memory pager to enter the ERROR
+  ** state.
+  */
+  if( MEMDB ){
+    assert( !isOpen(p->fd) );
+    assert( p->noSync );
+    assert( p->journalMode==PAGER_JOURNALMODE_OFF
+         || p->journalMode==PAGER_JOURNALMODE_MEMORY
+    );
+    assert( p->eState!=PAGER_ERROR && p->eState!=PAGER_OPEN );
+    assert( pagerUseWal(p)==0 );
+  }
+
+  /* If changeCountDone is set, a RESERVED lock or greater must be held
+  ** on the file.
+  */
+  assert( pPager->changeCountDone==0 || pPager->eLock>=RESERVED_LOCK );
+  assert( p->eLock!=PENDING_LOCK );
+
+  switch( p->eState ){
+    case PAGER_OPEN:
+      assert( !MEMDB );
+      assert( pPager->errCode==SQLITE_OK );
+      assert( sqlite3PcacheRefCount(pPager->pPCache)==0 || pPager->tempFile );
+      break;
+
+    case PAGER_READER:
+      assert( pPager->errCode==SQLITE_OK );
+      assert( p->eLock!=UNKNOWN_LOCK );
+      assert( p->eLock>=SHARED_LOCK );
+      break;
+
+    case PAGER_WRITER_LOCKED:
+      assert( p->eLock!=UNKNOWN_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      if( !pagerUseWal(pPager) ){
+        assert( p->eLock>=RESERVED_LOCK );
+      }
+      assert( pPager->dbSize==pPager->dbOrigSize );
+      assert( pPager->dbOrigSize==pPager->dbFileSize );
+      assert( pPager->dbOrigSize==pPager->dbHintSize );
+      assert( pPager->setSuper==0 );
+      break;
+
+    case PAGER_WRITER_CACHEMOD:
+      assert( p->eLock!=UNKNOWN_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      if( !pagerUseWal(pPager) ){
+        /* It is possible that if journal_mode=wal here that neither the
+        ** journal file nor the WAL file are open. This happens during
+        ** a rollback transaction that switches from journal_mode=off
+        ** to journal_mode=wal.
+        */
+        assert( p->eLock>=RESERVED_LOCK );
+        assert( isOpen(p->jfd)
+             || p->journalMode==PAGER_JOURNALMODE_OFF
+             || p->journalMode==PAGER_JOURNALMODE_WAL
+        );
+      }
+      assert( pPager->dbOrigSize==pPager->dbFileSize );
+      assert( pPager->dbOrigSize==pPager->dbHintSize );
+      break;
+
+    case PAGER_WRITER_DBMOD:
+      assert( p->eLock==EXCLUSIVE_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      assert( !pagerUseWal(pPager) );
+      assert( p->eLock>=EXCLUSIVE_LOCK );
+      assert( isOpen(p->jfd)
+           || p->journalMode==PAGER_JOURNALMODE_OFF
+           || p->journalMode==PAGER_JOURNALMODE_WAL
+           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
+      );
+      assert( pPager->dbOrigSize<=pPager->dbHintSize );
+      break;
+
+    case PAGER_WRITER_FINISHED:
+      assert( p->eLock==EXCLUSIVE_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      assert( !pagerUseWal(pPager) );
+      assert( isOpen(p->jfd)
+           || p->journalMode==PAGER_JOURNALMODE_OFF
+           || p->journalMode==PAGER_JOURNALMODE_WAL
+           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
+      );
+      break;
+
+    case PAGER_ERROR:
+      /* There must be at least one outstanding reference to the pager if
+      ** in ERROR state. Otherwise the pager should have already dropped
+      ** back to OPEN state.
+      */
+      assert( pPager->errCode!=SQLITE_OK );
+      assert( sqlite3PcacheRefCount(pPager->pPCache)>0 || pPager->tempFile );
+      break;
+  }
+
+  return 1;
+}
+#endif /* ifndef NDEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+** Return a pointer to a human readable string in a static buffer
+** containing the state of the Pager object passed as an argument. This
+** is intended to be used within debuggers. For example, as an alternative
+** to "print *pPager" in gdb:
+**
+** (gdb) printf "%s", print_pager_state(pPager)
+**
+** This routine has external linkage in order to suppress compiler warnings
+** about an unused function.  It is enclosed within SQLITE_DEBUG and so does
+** not appear in normal builds.
+*/
+char *print_pager_state(Pager *p){
+  static char zRet[1024];
+
+  sqlite3_snprintf(1024, zRet,
+      "Filename:      %s\n"
+      "State:         %s errCode=%d\n"
+      "Lock:          %s\n"
+      "Locking mode:  locking_mode=%s\n"
+      "Journal mode:  journal_mode=%s\n"
+      "Backing store: tempFile=%d memDb=%d useJournal=%d\n"
+      "Journal:       journalOff=%lld journalHdr=%lld\n"
+      "Size:          dbsize=%d dbOrigSize=%d dbFileSize=%d\n"
+      , p->zFilename
+      , p->eState==PAGER_OPEN            ? "OPEN" :
+        p->eState==PAGER_READER          ? "READER" :
+        p->eState==PAGER_WRITER_LOCKED   ? "WRITER_LOCKED" :
+        p->eState==PAGER_WRITER_CACHEMOD ? "WRITER_CACHEMOD" :
+        p->eState==PAGER_WRITER_DBMOD    ? "WRITER_DBMOD" :
+        p->eState==PAGER_WRITER_FINISHED ? "WRITER_FINISHED" :
+        p->eState==PAGER_ERROR           ? "ERROR" : "?error?"
+      , (int)p->errCode
+      , p->eLock==NO_LOCK         ? "NO_LOCK" :
+        p->eLock==RESERVED_LOCK   ? "RESERVED" :
+        p->eLock==EXCLUSIVE_LOCK  ? "EXCLUSIVE" :
+        p->eLock==SHARED_LOCK     ? "SHARED" :
+        p->eLock==UNKNOWN_LOCK    ? "UNKNOWN" : "?error?"
+      , p->exclusiveMode ? "exclusive" : "normal"
+      , p->journalMode==PAGER_JOURNALMODE_MEMORY   ? "memory" :
+        p->journalMode==PAGER_JOURNALMODE_OFF      ? "off" :
+        p->journalMode==PAGER_JOURNALMODE_DELETE   ? "delete" :
+        p->journalMode==PAGER_JOURNALMODE_PERSIST  ? "persist" :
+        p->journalMode==PAGER_JOURNALMODE_TRUNCATE ? "truncate" :
+        p->journalMode==PAGER_JOURNALMODE_WAL      ? "wal" : "?error?"
+      , (int)p->tempFile, (int)p->memDb, (int)p->useJournal
+      , p->journalOff, p->journalHdr
+      , (int)p->dbSize, (int)p->dbOrigSize, (int)p->dbFileSize
+  );
+
+  return zRet;
+}
+#endif
+
+/* Forward references to the various page getters */
+static int getPageNormal(Pager*,Pgno,DbPage**,int);
+static int getPageError(Pager*,Pgno,DbPage**,int);
+#if SQLITE_MAX_MMAP_SIZE>0
+static int getPageMMap(Pager*,Pgno,DbPage**,int);
+#endif
+
+/*
+** Set the Pager.xGet method for the appropriate routine used to fetch
+** content from the pager.
+*/
+static void setGetterMethod(Pager *pPager){
+  if( pPager->errCode ){
+    pPager->xGet = getPageError;
+#if SQLITE_MAX_MMAP_SIZE>0
+  }else if( USEFETCH(pPager) ){
+    pPager->xGet = getPageMMap;
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+  }else{
+    pPager->xGet = getPageNormal;
+  }
+}
+
+/*
+** Return true if it is necessary to write page *pPg into the sub-journal.
+** A page needs to be written into the sub-journal if there exists one
+** or more open savepoints for which:
+**
+**   * The page-number is less than or equal to PagerSavepoint.nOrig, and
+**   * The bit corresponding to the page-number is not set in
+**     PagerSavepoint.pInSavepoint.
+*/
+static int subjRequiresPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  PagerSavepoint *p;
+  Pgno pgno = pPg->pgno;
+  int i;
+  for(i=0; i<pPager->nSavepoint; i++){
+    p = &pPager->aSavepoint[i];
+    if( p->nOrig>=pgno && 0==sqlite3BitvecTestNotNull(p->pInSavepoint, pgno) ){
+      for(i=i+1; i<pPager->nSavepoint; i++){
+        pPager->aSavepoint[i].bTruncateOnRelease = 0;
+      }
+      return 1;
+    }
+  }
+  return 0;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Return true if the page is already in the journal file.
+*/
+static int pageInJournal(Pager *pPager, PgHdr *pPg){
+  return sqlite3BitvecTest(pPager->pInJournal, pPg->pgno);
+}
+#endif
+
+/*
+** Read a 32-bit integer from the given file descriptor.  Store the integer
+** that is read in *pRes.  Return SQLITE_OK if everything worked, or an
+** error code is something goes wrong.
+**
+** All values are stored on disk as big-endian.
+*/
+static int read32bits(sqlite3_file *fd, i64 offset, u32 *pRes){
+  unsigned char ac[4];
+  int rc = sqlite3OsRead(fd, ac, sizeof(ac), offset);
+  if( rc==SQLITE_OK ){
+    *pRes = sqlite3Get4byte(ac);
+  }
+  return rc;
+}
+
+/*
+** Write a 32-bit integer into a string buffer in big-endian byte order.
+*/
+#define put32bits(A,B)  sqlite3Put4byte((u8*)A,B)
+
+
+/*
+** Write a 32-bit integer into the given file descriptor.  Return SQLITE_OK
+** on success or an error code is something goes wrong.
+*/
+static int write32bits(sqlite3_file *fd, i64 offset, u32 val){
+  char ac[4];
+  put32bits(ac, val);
+  return sqlite3OsWrite(fd, ac, 4, offset);
+}
+
+/*
+** Unlock the database file to level eLock, which must be either NO_LOCK
+** or SHARED_LOCK. Regardless of whether or not the call to xUnlock()
+** succeeds, set the Pager.eLock variable to match the (attempted) new lock.
+**
+** Except, if Pager.eLock is set to UNKNOWN_LOCK when this function is
+** called, do not modify it. See the comment above the #define of
+** UNKNOWN_LOCK for an explanation of this.
+*/
+static int pagerUnlockDb(Pager *pPager, int eLock){
+  int rc = SQLITE_OK;
+
+  assert( !pPager->exclusiveMode || pPager->eLock==eLock );
+  assert( eLock==NO_LOCK || eLock==SHARED_LOCK );
+  assert( eLock!=NO_LOCK || pagerUseWal(pPager)==0 );
+  if( isOpen(pPager->fd) ){
+    assert( pPager->eLock>=eLock );
+    rc = pPager->noLock ? SQLITE_OK : sqlite3OsUnlock(pPager->fd, eLock);
+    if( pPager->eLock!=UNKNOWN_LOCK ){
+      pPager->eLock = (u8)eLock;
+    }
+    IOTRACE(("UNLOCK %p %d\n", pPager, eLock))
+  }
+  pPager->changeCountDone = pPager->tempFile; /* ticket fb3b3024ea238d5c */
+  return rc;
+}
+
+/*
+** Lock the database file to level eLock, which must be either SHARED_LOCK,
+** RESERVED_LOCK or EXCLUSIVE_LOCK. If the caller is successful, set the
+** Pager.eLock variable to the new locking state.
+**
+** Except, if Pager.eLock is set to UNKNOWN_LOCK when this function is
+** called, do not modify it unless the new locking state is EXCLUSIVE_LOCK.
+** See the comment above the #define of UNKNOWN_LOCK for an explanation
+** of this.
+*/
+static int pagerLockDb(Pager *pPager, int eLock){
+  int rc = SQLITE_OK;
+
+  assert( eLock==SHARED_LOCK || eLock==RESERVED_LOCK || eLock==EXCLUSIVE_LOCK );
+  if( pPager->eLock<eLock || pPager->eLock==UNKNOWN_LOCK ){
+    rc = pPager->noLock ? SQLITE_OK : sqlite3OsLock(pPager->fd, eLock);
+    if( rc==SQLITE_OK && (pPager->eLock!=UNKNOWN_LOCK||eLock==EXCLUSIVE_LOCK) ){
+      pPager->eLock = (u8)eLock;
+      IOTRACE(("LOCK %p %d\n", pPager, eLock))
+    }
+  }
+  return rc;
+}
+
+/*
+** This function determines whether or not the atomic-write or
+** atomic-batch-write optimizations can be used with this pager. The
+** atomic-write optimization can be used if:
+**
+**  (a) the value returned by OsDeviceCharacteristics() indicates that
+**      a database page may be written atomically, and
+**  (b) the value returned by OsSectorSize() is less than or equal
+**      to the page size.
+**
+** If it can be used, then the value returned is the size of the journal
+** file when it contains rollback data for exactly one page.
+**
+** The atomic-batch-write optimization can be used if OsDeviceCharacteristics()
+** returns a value with the SQLITE_IOCAP_BATCH_ATOMIC bit set. -1 is
+** returned in this case.
+**
+** If neither optimization can be used, 0 is returned.
+*/
+static int jrnlBufferSize(Pager *pPager){
+  assert( !MEMDB );
+
+#if defined(SQLITE_ENABLE_ATOMIC_WRITE) \
+ || defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+  int dc;                           /* Device characteristics */
+
+  assert( isOpen(pPager->fd) );
+  dc = sqlite3OsDeviceCharacteristics(pPager->fd);
+#else
+  UNUSED_PARAMETER(pPager);
+#endif
+
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+  if( pPager->dbSize>0 && (dc&SQLITE_IOCAP_BATCH_ATOMIC) ){
+    return -1;
+  }
+#endif
+
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+  {
+    int nSector = pPager->sectorSize;
+    int szPage = pPager->pageSize;
+
+    assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
+    assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
+    if( 0==(dc&(SQLITE_IOCAP_ATOMIC|(szPage>>8)) || nSector>szPage) ){
+      return 0;
+    }
+  }
+
+  return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
+#endif
+
+  return 0;
+}
+
+/*
+** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
+** on the cache using a hash function.  This is used for testing
+** and debugging only.
+*/
+#ifdef SQLITE_CHECK_PAGES
+/*
+** Return a 32-bit hash of the page data for pPage.
+*/
+static u32 pager_datahash(int nByte, unsigned char *pData){
+  u32 hash = 0;
+  int i;
+  for(i=0; i<nByte; i++){
+    hash = (hash*1039) + pData[i];
+  }
+  return hash;
+}
+static u32 pager_pagehash(PgHdr *pPage){
+  return pager_datahash(pPage->pPager->pageSize, (unsigned char *)pPage->pData);
+}
+static void pager_set_pagehash(PgHdr *pPage){
+  pPage->pageHash = pager_pagehash(pPage);
+}
+
+/*
+** The CHECK_PAGE macro takes a PgHdr* as an argument. If SQLITE_CHECK_PAGES
+** is defined, and NDEBUG is not defined, an assert() statement checks
+** that the page is either dirty or still matches the calculated page-hash.
+*/
+#define CHECK_PAGE(x) checkPage(x)
+static void checkPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( (pPg->flags&PGHDR_DIRTY) || pPg->pageHash==pager_pagehash(pPg) );
+}
+
+#else
+#define pager_datahash(X,Y)  0
+#define pager_pagehash(X)  0
+#define pager_set_pagehash(X)
+#define CHECK_PAGE(x)
+#endif  /* SQLITE_CHECK_PAGES */
+
+/*
+** When this is called the journal file for pager pPager must be open.
+** This function attempts to read a super-journal file name from the
+** end of the file and, if successful, copies it into memory supplied
+** by the caller. See comments above writeSuperJournal() for the format
+** used to store a super-journal file name at the end of a journal file.
+**
+** zSuper must point to a buffer of at least nSuper bytes allocated by
+** the caller. This should be sqlite3_vfs.mxPathname+1 (to ensure there is
+** enough space to write the super-journal name). If the super-journal
+** name in the journal is longer than nSuper bytes (including a
+** nul-terminator), then this is handled as if no super-journal name
+** were present in the journal.
+**
+** If a super-journal file name is present at the end of the journal
+** file, then it is copied into the buffer pointed to by zSuper. A
+** nul-terminator byte is appended to the buffer following the
+** super-journal file name.
+**
+** If it is determined that no super-journal file name is present
+** zSuper[0] is set to 0 and SQLITE_OK returned.
+**
+** If an error occurs while reading from the journal file, an SQLite
+** error code is returned.
+*/
+static int readSuperJournal(sqlite3_file *pJrnl, char *zSuper, u32 nSuper){
+  int rc;                    /* Return code */
+  u32 len;                   /* Length in bytes of super-journal name */
+  i64 szJ;                   /* Total size in bytes of journal file pJrnl */
+  u32 cksum;                 /* MJ checksum value read from journal */
+  u32 u;                     /* Unsigned loop counter */
+  unsigned char aMagic[8];   /* A buffer to hold the magic header */
+  zSuper[0] = '\0';
+
+  if( SQLITE_OK!=(rc = sqlite3OsFileSize(pJrnl, &szJ))
+   || szJ<16
+   || SQLITE_OK!=(rc = read32bits(pJrnl, szJ-16, &len))
+   || len>=nSuper
+   || len>szJ-16
+   || len==0
+   || SQLITE_OK!=(rc = read32bits(pJrnl, szJ-12, &cksum))
+   || SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, aMagic, 8, szJ-8))
+   || memcmp(aMagic, aJournalMagic, 8)
+   || SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, zSuper, len, szJ-16-len))
+  ){
+    return rc;
+  }
+
+  /* See if the checksum matches the super-journal name */
+  for(u=0; u<len; u++){
+    cksum -= zSuper[u];
+  }
+  if( cksum ){
+    /* If the checksum doesn't add up, then one or more of the disk sectors
+    ** containing the super-journal filename is corrupted. This means
+    ** definitely roll back, so just return SQLITE_OK and report a (nul)
+    ** super-journal filename.
+    */
+    len = 0;
+  }
+  zSuper[len] = '\0';
+  zSuper[len+1] = '\0';
+
+  return SQLITE_OK;
+}
+
+/*
+** Return the offset of the sector boundary at or immediately
+** following the value in pPager->journalOff, assuming a sector
+** size of pPager->sectorSize bytes.
+**
+** i.e for a sector size of 512:
+**
+**   Pager.journalOff          Return value
+**   ---------------------------------------
+**   0                         0
+**   512                       512
+**   100                       512
+**   2000                      2048
+**
+*/
+static i64 journalHdrOffset(Pager *pPager){
+  i64 offset = 0;
+  i64 c = pPager->journalOff;
+  if( c ){
+    offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager);
+  }
+  assert( offset%JOURNAL_HDR_SZ(pPager)==0 );
+  assert( offset>=c );
+  assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
+  return offset;
+}
+
+/*
+** The journal file must be open when this function is called.
+**
+** This function is a no-op if the journal file has not been written to
+** within the current transaction (i.e. if Pager.journalOff==0).
+**
+** If doTruncate is non-zero or the Pager.journalSizeLimit variable is
+** set to 0, then truncate the journal file to zero bytes in size. Otherwise,
+** zero the 28-byte header at the start of the journal file. In either case,
+** if the pager is not in no-sync mode, sync the journal file immediately
+** after writing or truncating it.
+**
+** If Pager.journalSizeLimit is set to a positive, non-zero value, and
+** following the truncation or zeroing described above the size of the
+** journal file in bytes is larger than this value, then truncate the
+** journal file to Pager.journalSizeLimit bytes. The journal file does
+** not need to be synced following this operation.
+**
+** If an IO error occurs, abandon processing and return the IO error code.
+** Otherwise, return SQLITE_OK.
+*/
+static int zeroJournalHdr(Pager *pPager, int doTruncate){
+  int rc = SQLITE_OK;                               /* Return code */
+  assert( isOpen(pPager->jfd) );
+  assert( !sqlite3JournalIsInMemory(pPager->jfd) );
+  if( pPager->journalOff ){
+    const i64 iLimit = pPager->journalSizeLimit;    /* Local cache of jsl */
+
+    IOTRACE(("JZEROHDR %p\n", pPager))
+    if( doTruncate || iLimit==0 ){
+      rc = sqlite3OsTruncate(pPager->jfd, 0);
+    }else{
+      static const char zeroHdr[28] = {0};
+      rc = sqlite3OsWrite(pPager->jfd, zeroHdr, sizeof(zeroHdr), 0);
+    }
+    if( rc==SQLITE_OK && !pPager->noSync ){
+      rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_DATAONLY|pPager->syncFlags);
+    }
+
+    /* At this point the transaction is committed but the write lock
+    ** is still held on the file. If there is a size limit configured for
+    ** the persistent journal and the journal file currently consumes more
+    ** space than that limit allows for, truncate it now. There is no need
+    ** to sync the file following this operation.
+    */
+    if( rc==SQLITE_OK && iLimit>0 ){
+      i64 sz;
+      rc = sqlite3OsFileSize(pPager->jfd, &sz);
+      if( rc==SQLITE_OK && sz>iLimit ){
+        rc = sqlite3OsTruncate(pPager->jfd, iLimit);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** The journal file must be open when this routine is called. A journal
+** header (JOURNAL_HDR_SZ bytes) is written into the journal file at the
+** current location.
+**
+** The format for the journal header is as follows:
+** - 8 bytes: Magic identifying journal format.
+** - 4 bytes: Number of records in journal, or -1 no-sync mode is on.
+** - 4 bytes: Random number used for page hash.
+** - 4 bytes: Initial database page count.
+** - 4 bytes: Sector size used by the process that wrote this journal.
+** - 4 bytes: Database page size.
+**
+** Followed by (JOURNAL_HDR_SZ - 28) bytes of unused space.
+*/
+static int writeJournalHdr(Pager *pPager){
+  int rc = SQLITE_OK;                 /* Return code */
+  char *zHeader = pPager->pTmpSpace;  /* Temporary space used to build header */
+  u32 nHeader = (u32)pPager->pageSize;/* Size of buffer pointed to by zHeader */
+  u32 nWrite;                         /* Bytes of header sector written */
+  int ii;                             /* Loop counter */
+
+  assert( isOpen(pPager->jfd) );      /* Journal file must be open. */
+
+  if( nHeader>JOURNAL_HDR_SZ(pPager) ){
+    nHeader = JOURNAL_HDR_SZ(pPager);
+  }
+
+  /* If there are active savepoints and any of them were created
+  ** since the most recent journal header was written, update the
+  ** PagerSavepoint.iHdrOffset fields now.
+  */
+  for(ii=0; ii<pPager->nSavepoint; ii++){
+    if( pPager->aSavepoint[ii].iHdrOffset==0 ){
+      pPager->aSavepoint[ii].iHdrOffset = pPager->journalOff;
+    }
+  }
+
+  pPager->journalHdr = pPager->journalOff = journalHdrOffset(pPager);
+
+  /*
+  ** Write the nRec Field - the number of page records that follow this
+  ** journal header. Normally, zero is written to this value at this time.
+  ** After the records are added to the journal (and the journal synced,
+  ** if in full-sync mode), the zero is overwritten with the true number
+  ** of records (see syncJournal()).
+  **
+  ** A faster alternative is to write 0xFFFFFFFF to the nRec field. When
+  ** reading the journal this value tells SQLite to assume that the
+  ** rest of the journal file contains valid page records. This assumption
+  ** is dangerous, as if a failure occurred whilst writing to the journal
+  ** file it may contain some garbage data. There are two scenarios
+  ** where this risk can be ignored:
+  **
+  **   * When the pager is in no-sync mode. Corruption can follow a
+  **     power failure in this case anyway.
+  **
+  **   * When the SQLITE_IOCAP_SAFE_APPEND flag is set. This guarantees
+  **     that garbage data is never appended to the journal file.
+  */
+  assert( isOpen(pPager->fd) || pPager->noSync );
+  if( pPager->noSync || (pPager->journalMode==PAGER_JOURNALMODE_MEMORY)
+   || (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND)
+  ){
+    memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
+    put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
+  }else{
+    memset(zHeader, 0, sizeof(aJournalMagic)+4);
+  }
+
+
+
+  /* The random check-hash initializer */
+  if( pPager->journalMode!=PAGER_JOURNALMODE_MEMORY ){
+    sqlite3_randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
+  }
+#ifdef SQLITE_DEBUG
+  else{
+    /* The Pager.cksumInit variable is usually randomized above to protect
+    ** against there being existing records in the journal file. This is
+    ** dangerous, as following a crash they may be mistaken for records
+    ** written by the current transaction and rolled back into the database
+    ** file, causing corruption. The following assert statements verify
+    ** that this is not required in "journal_mode=memory" mode, as in that
+    ** case the journal file is always 0 bytes in size at this point.
+    ** It is advantageous to avoid the sqlite3_randomness() call if possible
+    ** as it takes the global PRNG mutex.  */
+    i64 sz = 0;
+    sqlite3OsFileSize(pPager->jfd, &sz);
+    assert( sz==0 );
+    assert( pPager->journalOff==journalHdrOffset(pPager) );
+    assert( sqlite3JournalIsInMemory(pPager->jfd) );
+  }
+#endif
+  put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
+
+  /* The initial database size */
+  put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbOrigSize);
+  /* The assumed sector size for this process */
+  put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);
+
+  /* The page size */
+  put32bits(&zHeader[sizeof(aJournalMagic)+16], pPager->pageSize);
+
+  /* Initializing the tail of the buffer is not necessary.  Everything
+  ** works find if the following memset() is omitted.  But initializing
+  ** the memory prevents valgrind from complaining, so we are willing to
+  ** take the performance hit.
+  */
+  memset(&zHeader[sizeof(aJournalMagic)+20], 0,
+         nHeader-(sizeof(aJournalMagic)+20));
+
+  /* In theory, it is only necessary to write the 28 bytes that the
+  ** journal header consumes to the journal file here. Then increment the
+  ** Pager.journalOff variable by JOURNAL_HDR_SZ so that the next
+  ** record is written to the following sector (leaving a gap in the file
+  ** that will be implicitly filled in by the OS).
+  **
+  ** However it has been discovered that on some systems this pattern can
+  ** be significantly slower than contiguously writing data to the file,
+  ** even if that means explicitly writing data to the block of
+  ** (JOURNAL_HDR_SZ - 28) bytes that will not be used. So that is what
+  ** is done.
+  **
+  ** The loop is required here in case the sector-size is larger than the
+  ** database page size. Since the zHeader buffer is only Pager.pageSize
+  ** bytes in size, more than one call to sqlite3OsWrite() may be required
+  ** to populate the entire journal header sector.
+  */
+  for(nWrite=0; rc==SQLITE_OK&&nWrite<JOURNAL_HDR_SZ(pPager); nWrite+=nHeader){
+    IOTRACE(("JHDR %p %lld %d\n", pPager, pPager->journalHdr, nHeader))
+    rc = sqlite3OsWrite(pPager->jfd, zHeader, nHeader, pPager->journalOff);
+    assert( pPager->journalHdr <= pPager->journalOff );
+    pPager->journalOff += nHeader;
+  }
+
+  return rc;
+}
+
+/*
+** The journal file must be open when this is called. A journal header file
+** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
+** file. The current location in the journal file is given by
+** pPager->journalOff. See comments above function writeJournalHdr() for
+** a description of the journal header format.
+**
+** If the header is read successfully, *pNRec is set to the number of
+** page records following this header and *pDbSize is set to the size of the
+** database before the transaction began, in pages. Also, pPager->cksumInit
+** is set to the value read from the journal header. SQLITE_OK is returned
+** in this case.
+**
+** If the journal header file appears to be corrupted, SQLITE_DONE is
+** returned and *pNRec and *PDbSize are undefined.  If JOURNAL_HDR_SZ bytes
+** cannot be read from the journal file an error code is returned.
+*/
+static int readJournalHdr(
+  Pager *pPager,               /* Pager object */
+  int isHot,
+  i64 journalSize,             /* Size of the open journal file in bytes */
+  u32 *pNRec,                  /* OUT: Value read from the nRec field */
+  u32 *pDbSize                 /* OUT: Value of original database size field */
+){
+  int rc;                      /* Return code */
+  unsigned char aMagic[8];     /* A buffer to hold the magic header */
+  i64 iHdrOff;                 /* Offset of journal header being read */
+
+  assert( isOpen(pPager->jfd) );      /* Journal file must be open. */
+
+  /* Advance Pager.journalOff to the start of the next sector. If the
+  ** journal file is too small for there to be a header stored at this
+  ** point, return SQLITE_DONE.
+  */
+  pPager->journalOff = journalHdrOffset(pPager);
+  if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
+    return SQLITE_DONE;
+  }
+  iHdrOff = pPager->journalOff;
+
+  /* Read in the first 8 bytes of the journal header. If they do not match
+  ** the  magic string found at the start of each journal header, return
+  ** SQLITE_DONE. If an IO error occurs, return an error code. Otherwise,
+  ** proceed.
+  */
+  if( isHot || iHdrOff!=pPager->journalHdr ){
+    rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic), iHdrOff);
+    if( rc ){
+      return rc;
+    }
+    if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
+      return SQLITE_DONE;
+    }
+  }
+
+  /* Read the first three 32-bit fields of the journal header: The nRec
+  ** field, the checksum-initializer and the database size at the start
+  ** of the transaction. Return an error code if anything goes wrong.
+  */
+  if( SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+8, pNRec))
+   || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+12, &pPager->cksumInit))
+   || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+16, pDbSize))
+  ){
+    return rc;
+  }
+
+  if( pPager->journalOff==0 ){
+    u32 iPageSize;               /* Page-size field of journal header */
+    u32 iSectorSize;             /* Sector-size field of journal header */
+
+    /* Read the page-size and sector-size journal header fields. */
+    if( SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+20, &iSectorSize))
+     || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+24, &iPageSize))
+    ){
+      return rc;
+    }
+
+    /* Versions of SQLite prior to 3.5.8 set the page-size field of the
+    ** journal header to zero. In this case, assume that the Pager.pageSize
+    ** variable is already set to the correct page size.
+    */
+    if( iPageSize==0 ){
+      iPageSize = pPager->pageSize;
+    }
+
+    /* Check that the values read from the page-size and sector-size fields
+    ** are within range. To be 'in range', both values need to be a power
+    ** of two greater than or equal to 512 or 32, and not greater than their
+    ** respective compile time maximum limits.
+    */
+    if( iPageSize<512                  || iSectorSize<32
+     || iPageSize>SQLITE_MAX_PAGE_SIZE || iSectorSize>MAX_SECTOR_SIZE
+     || ((iPageSize-1)&iPageSize)!=0   || ((iSectorSize-1)&iSectorSize)!=0
+    ){
+      /* If the either the page-size or sector-size in the journal-header is
+      ** invalid, then the process that wrote the journal-header must have
+      ** crashed before the header was synced. In this case stop reading
+      ** the journal file here.
+      */
+      return SQLITE_DONE;
+    }
+
+    /* Update the page-size to match the value read from the journal.
+    ** Use a testcase() macro to make sure that malloc failure within
+    ** PagerSetPagesize() is tested.
+    */
+    rc = sqlite3PagerSetPagesize(pPager, &iPageSize, -1);
+    testcase( rc!=SQLITE_OK );
+
+    /* Update the assumed sector-size to match the value used by
+    ** the process that created this journal. If this journal was
+    ** created by a process other than this one, then this routine
+    ** is being called from within pager_playback(). The local value
+    ** of Pager.sectorSize is restored at the end of that routine.
+    */
+    pPager->sectorSize = iSectorSize;
+  }
+
+  pPager->journalOff += JOURNAL_HDR_SZ(pPager);
+  return rc;
+}
+
+
+/*
+** Write the supplied super-journal name into the journal file for pager
+** pPager at the current location. The super-journal name must be the last
+** thing written to a journal file. If the pager is in full-sync mode, the
+** journal file descriptor is advanced to the next sector boundary before
+** anything is written. The format is:
+**
+**   + 4 bytes: PAGER_SJ_PGNO.
+**   + N bytes: super-journal filename in utf-8.
+**   + 4 bytes: N (length of super-journal name in bytes, no nul-terminator).
+**   + 4 bytes: super-journal name checksum.
+**   + 8 bytes: aJournalMagic[].
+**
+** The super-journal page checksum is the sum of the bytes in the super-journal
+** name, where each byte is interpreted as a signed 8-bit integer.
+**
+** If zSuper is a NULL pointer (occurs for a single database transaction),
+** this call is a no-op.
+*/
+static int writeSuperJournal(Pager *pPager, const char *zSuper){
+  int rc;                          /* Return code */
+  int nSuper;                      /* Length of string zSuper */
+  i64 iHdrOff;                     /* Offset of header in journal file */
+  i64 jrnlSize;                    /* Size of journal file on disk */
+  u32 cksum = 0;                   /* Checksum of string zSuper */
+
+  assert( pPager->setSuper==0 );
+  assert( !pagerUseWal(pPager) );
+
+  if( !zSuper
+   || pPager->journalMode==PAGER_JOURNALMODE_MEMORY
+   || !isOpen(pPager->jfd)
+  ){
+    return SQLITE_OK;
+  }
+  pPager->setSuper = 1;
+  assert( pPager->journalHdr <= pPager->journalOff );
+
+  /* Calculate the length in bytes and the checksum of zSuper */
+  for(nSuper=0; zSuper[nSuper]; nSuper++){
+    cksum += zSuper[nSuper];
+  }
+
+  /* If in full-sync mode, advance to the next disk sector before writing
+  ** the super-journal name. This is in case the previous page written to
+  ** the journal has already been synced.
+  */
+  if( pPager->fullSync ){
+    pPager->journalOff = journalHdrOffset(pPager);
+  }
+  iHdrOff = pPager->journalOff;
+
+  /* Write the super-journal data to the end of the journal file. If
+  ** an error occurs, return the error code to the caller.
+  */
+  if( (0 != (rc = write32bits(pPager->jfd, iHdrOff, PAGER_SJ_PGNO(pPager))))
+   || (0 != (rc = sqlite3OsWrite(pPager->jfd, zSuper, nSuper, iHdrOff+4)))
+   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nSuper, nSuper)))
+   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nSuper+4, cksum)))
+   || (0 != (rc = sqlite3OsWrite(pPager->jfd, aJournalMagic, 8,
+                                 iHdrOff+4+nSuper+8)))
+  ){
+    return rc;
+  }
+  pPager->journalOff += (nSuper+20);
+
+  /* If the pager is in persistent-journal mode, then the physical
+  ** journal-file may extend past the end of the super-journal name
+  ** and 8 bytes of magic data just written to the file. This is
+  ** dangerous because the code to rollback a hot-journal file
+  ** will not be able to find the super-journal name to determine
+  ** whether or not the journal is hot.
+  **
+  ** Easiest thing to do in this scenario is to truncate the journal
+  ** file to the required size.
+  */
+  if( SQLITE_OK==(rc = sqlite3OsFileSize(pPager->jfd, &jrnlSize))
+   && jrnlSize>pPager->journalOff
+  ){
+    rc = sqlite3OsTruncate(pPager->jfd, pPager->journalOff);
+  }
+  return rc;
+}
+
+/*
+** Discard the entire contents of the in-memory page-cache.
+*/
+static void pager_reset(Pager *pPager){
+  pPager->iDataVersion++;
+  sqlite3BackupRestart(pPager->pBackup);
+  sqlite3PcacheClear(pPager->pPCache);
+}
+
+/*
+** Return the pPager->iDataVersion value
+*/
+SQLITE_PRIVATE u32 sqlite3PagerDataVersion(Pager *pPager){
+  return pPager->iDataVersion;
+}
+
+/*
+** Free all structures in the Pager.aSavepoint[] array and set both
+** Pager.aSavepoint and Pager.nSavepoint to zero. Close the sub-journal
+** if it is open and the pager is not in exclusive mode.
+*/
+static void releaseAllSavepoints(Pager *pPager){
+  int ii;               /* Iterator for looping through Pager.aSavepoint */
+  for(ii=0; ii<pPager->nSavepoint; ii++){
+    sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
+  }
+  if( !pPager->exclusiveMode || sqlite3JournalIsInMemory(pPager->sjfd) ){
+    sqlite3OsClose(pPager->sjfd);
+  }
+  sqlite3_free(pPager->aSavepoint);
+  pPager->aSavepoint = 0;
+  pPager->nSavepoint = 0;
+  pPager->nSubRec = 0;
+}
+
+/*
+** Set the bit number pgno in the PagerSavepoint.pInSavepoint
+** bitvecs of all open savepoints. Return SQLITE_OK if successful
+** or SQLITE_NOMEM if a malloc failure occurs.
+*/
+static int addToSavepointBitvecs(Pager *pPager, Pgno pgno){
+  int ii;                   /* Loop counter */
+  int rc = SQLITE_OK;       /* Result code */
+
+  for(ii=0; ii<pPager->nSavepoint; ii++){
+    PagerSavepoint *p = &pPager->aSavepoint[ii];
+    if( pgno<=p->nOrig ){
+      rc |= sqlite3BitvecSet(p->pInSavepoint, pgno);
+      testcase( rc==SQLITE_NOMEM );
+      assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is a no-op if the pager is in exclusive mode and not
+** in the ERROR state. Otherwise, it switches the pager to PAGER_OPEN
+** state.
+**
+** If the pager is not in exclusive-access mode, the database file is
+** completely unlocked. If the file is unlocked and the file-system does
+** not exhibit the UNDELETABLE_WHEN_OPEN property, the journal file is
+** closed (if it is open).
+**
+** If the pager is in ERROR state when this function is called, the
+** contents of the pager cache are discarded before switching back to
+** the OPEN state. Regardless of whether the pager is in exclusive-mode
+** or not, any journal file left in the file-system will be treated
+** as a hot-journal and rolled back the next time a read-transaction
+** is opened (by this or by any other connection).
+*/
+static void pager_unlock(Pager *pPager){
+
+  assert( pPager->eState==PAGER_READER
+       || pPager->eState==PAGER_OPEN
+       || pPager->eState==PAGER_ERROR
+  );
+
+  sqlite3BitvecDestroy(pPager->pInJournal);
+  pPager->pInJournal = 0;
+  releaseAllSavepoints(pPager);
+
+  if( pagerUseWal(pPager) ){
+    assert( !isOpen(pPager->jfd) );
+    sqlite3WalEndReadTransaction(pPager->pWal);
+    pPager->eState = PAGER_OPEN;
+  }else if( !pPager->exclusiveMode ){
+    int rc;                       /* Error code returned by pagerUnlockDb() */
+    int iDc = isOpen(pPager->fd)?sqlite3OsDeviceCharacteristics(pPager->fd):0;
+
+    /* If the operating system support deletion of open files, then
+    ** close the journal file when dropping the database lock.  Otherwise
+    ** another connection with journal_mode=delete might delete the file
+    ** out from under us.
+    */
+    assert( (PAGER_JOURNALMODE_MEMORY   & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_OFF      & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_WAL      & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_DELETE   & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_TRUNCATE & 5)==1 );
+    assert( (PAGER_JOURNALMODE_PERSIST  & 5)==1 );
+    if( 0==(iDc & SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN)
+     || 1!=(pPager->journalMode & 5)
+    ){
+      sqlite3OsClose(pPager->jfd);
+    }
+
+    /* If the pager is in the ERROR state and the call to unlock the database
+    ** file fails, set the current lock to UNKNOWN_LOCK. See the comment
+    ** above the #define for UNKNOWN_LOCK for an explanation of why this
+    ** is necessary.
+    */
+    rc = pagerUnlockDb(pPager, NO_LOCK);
+    if( rc!=SQLITE_OK && pPager->eState==PAGER_ERROR ){
+      pPager->eLock = UNKNOWN_LOCK;
+    }
+
+    /* The pager state may be changed from PAGER_ERROR to PAGER_OPEN here
+    ** without clearing the error code. This is intentional - the error
+    ** code is cleared and the cache reset in the block below.
+    */
+    assert( pPager->errCode || pPager->eState!=PAGER_ERROR );
+    pPager->eState = PAGER_OPEN;
+  }
+
+  /* If Pager.errCode is set, the contents of the pager cache cannot be
+  ** trusted. Now that there are no outstanding references to the pager,
+  ** it can safely move back to PAGER_OPEN state. This happens in both
+  ** normal and exclusive-locking mode.
+  */
+  assert( pPager->errCode==SQLITE_OK || !MEMDB );
+  if( pPager->errCode ){
+    if( pPager->tempFile==0 ){
+      pager_reset(pPager);
+      pPager->changeCountDone = 0;
+      pPager->eState = PAGER_OPEN;
+    }else{
+      pPager->eState = (isOpen(pPager->jfd) ? PAGER_OPEN : PAGER_READER);
+    }
+    if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);
+    pPager->errCode = SQLITE_OK;
+    setGetterMethod(pPager);
+  }
+
+  pPager->journalOff = 0;
+  pPager->journalHdr = 0;
+  pPager->setSuper = 0;
+}
+
+/*
+** This function is called whenever an IOERR or FULL error that requires
+** the pager to transition into the ERROR state may have occurred.
+** The first argument is a pointer to the pager structure, the second
+** the error-code about to be returned by a pager API function. The
+** value returned is a copy of the second argument to this function.
+**
+** If the second argument is SQLITE_FULL, SQLITE_IOERR or one of the
+** IOERR sub-codes, the pager enters the ERROR state and the error code
+** is stored in Pager.errCode. While the pager remains in the ERROR state,
+** all major API calls on the Pager will immediately return Pager.errCode.
+**
+** The ERROR state indicates that the contents of the pager-cache
+** cannot be trusted. This state can be cleared by completely discarding
+** the contents of the pager-cache. If a transaction was active when
+** the persistent error occurred, then the rollback journal may need
+** to be replayed to restore the contents of the database file (as if
+** it were a hot-journal).
+*/
+static int pager_error(Pager *pPager, int rc){
+  int rc2 = rc & 0xff;
+  assert( rc==SQLITE_OK || !MEMDB );
+  assert(
+       pPager->errCode==SQLITE_FULL ||
+       pPager->errCode==SQLITE_OK ||
+       (pPager->errCode & 0xff)==SQLITE_IOERR
+  );
+  if( rc2==SQLITE_FULL || rc2==SQLITE_IOERR ){
+    pPager->errCode = rc;
+    pPager->eState = PAGER_ERROR;
+    setGetterMethod(pPager);
+  }
+  return rc;
+}
+
+static int pager_truncate(Pager *pPager, Pgno nPage);
+
+/*
+** The write transaction open on pPager is being committed (bCommit==1)
+** or rolled back (bCommit==0).
+**
+** Return TRUE if and only if all dirty pages should be flushed to disk.
+**
+** Rules:
+**
+**   *  For non-TEMP databases, always sync to disk.  This is necessary
+**      for transactions to be durable.
+**
+**   *  Sync TEMP database only on a COMMIT (not a ROLLBACK) when the backing
+**      file has been created already (via a spill on pagerStress()) and
+**      when the number of dirty pages in memory exceeds 25% of the total
+**      cache size.
+*/
+static int pagerFlushOnCommit(Pager *pPager, int bCommit){
+  if( pPager->tempFile==0 ) return 1;
+  if( !bCommit ) return 0;
+  if( !isOpen(pPager->fd) ) return 0;
+  return (sqlite3PCachePercentDirty(pPager->pPCache)>=25);
+}
+
+/*
+** This routine ends a transaction. A transaction is usually ended by
+** either a COMMIT or a ROLLBACK operation. This routine may be called
+** after rollback of a hot-journal, or if an error occurs while opening
+** the journal file or writing the very first journal-header of a
+** database transaction.
+**
+** This routine is never called in PAGER_ERROR state. If it is called
+** in PAGER_NONE or PAGER_SHARED state and the lock held is less
+** exclusive than a RESERVED lock, it is a no-op.
+**
+** Otherwise, any active savepoints are released.
+**
+** If the journal file is open, then it is "finalized". Once a journal
+** file has been finalized it is not possible to use it to roll back a
+** transaction. Nor will it be considered to be a hot-journal by this
+** or any other database connection. Exactly how a journal is finalized
+** depends on whether or not the pager is running in exclusive mode and
+** the current journal-mode (Pager.journalMode value), as follows:
+**
+**   journalMode==MEMORY
+**     Journal file descriptor is simply closed. This destroys an
+**     in-memory journal.
+**
+**   journalMode==TRUNCATE
+**     Journal file is truncated to zero bytes in size.
+**
+**   journalMode==PERSIST
+**     The first 28 bytes of the journal file are zeroed. This invalidates
+**     the first journal header in the file, and hence the entire journal
+**     file. An invalid journal file cannot be rolled back.
+**
+**   journalMode==DELETE
+**     The journal file is closed and deleted using sqlite3OsDelete().
+**
+**     If the pager is running in exclusive mode, this method of finalizing
+**     the journal file is never used. Instead, if the journalMode is
+**     DELETE and the pager is in exclusive mode, the method described under
+**     journalMode==PERSIST is used instead.
+**
+** After the journal is finalized, the pager moves to PAGER_READER state.
+** If running in non-exclusive rollback mode, the lock on the file is
+** downgraded to a SHARED_LOCK.
+**
+** SQLITE_OK is returned if no error occurs. If an error occurs during
+** any of the IO operations to finalize the journal file or unlock the
+** database then the IO error code is returned to the user. If the
+** operation to finalize the journal file fails, then the code still
+** tries to unlock the database file if not in exclusive mode. If the
+** unlock operation fails as well, then the first error code related
+** to the first error encountered (the journal finalization one) is
+** returned.
+*/
+static int pager_end_transaction(Pager *pPager, int hasSuper, int bCommit){
+  int rc = SQLITE_OK;      /* Error code from journal finalization operation */
+  int rc2 = SQLITE_OK;     /* Error code from db file unlock operation */
+
+  /* Do nothing if the pager does not have an open write transaction
+  ** or at least a RESERVED lock. This function may be called when there
+  ** is no write-transaction active but a RESERVED or greater lock is
+  ** held under two circumstances:
+  **
+  **   1. After a successful hot-journal rollback, it is called with
+  **      eState==PAGER_NONE and eLock==EXCLUSIVE_LOCK.
+  **
+  **   2. If a connection with locking_mode=exclusive holding an EXCLUSIVE
+  **      lock switches back to locking_mode=normal and then executes a
+  **      read-transaction, this function is called with eState==PAGER_READER
+  **      and eLock==EXCLUSIVE_LOCK when the read-transaction is closed.
+  */
+  assert( assert_pager_state(pPager) );
+  assert( pPager->eState!=PAGER_ERROR );
+  if( pPager->eState<PAGER_WRITER_LOCKED && pPager->eLock<RESERVED_LOCK ){
+    return SQLITE_OK;
+  }
+
+  releaseAllSavepoints(pPager);
+  assert( isOpen(pPager->jfd) || pPager->pInJournal==0
+      || (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
+  );
+  if( isOpen(pPager->jfd) ){
+    assert( !pagerUseWal(pPager) );
+
+    /* Finalize the journal file. */
+    if( sqlite3JournalIsInMemory(pPager->jfd) ){
+      /* assert( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ); */
+      sqlite3OsClose(pPager->jfd);
+    }else if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE ){
+      if( pPager->journalOff==0 ){
+        rc = SQLITE_OK;
+      }else{
+        rc = sqlite3OsTruncate(pPager->jfd, 0);
+        if( rc==SQLITE_OK && pPager->fullSync ){
+          /* Make sure the new file size is written into the inode right away.
+          ** Otherwise the journal might resurrect following a power loss and
+          ** cause the last transaction to roll back.  See
+          ** https://bugzilla.mozilla.org/show_bug.cgi?id=1072773
+          */
+          rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags);
+        }
+      }
+      pPager->journalOff = 0;
+    }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
+      || (pPager->exclusiveMode && pPager->journalMode<PAGER_JOURNALMODE_WAL)
+    ){
+      rc = zeroJournalHdr(pPager, hasSuper||pPager->tempFile);
+      pPager->journalOff = 0;
+    }else{
+      /* This branch may be executed with Pager.journalMode==MEMORY if
+      ** a hot-journal was just rolled back. In this case the journal
+      ** file should be closed and deleted. If this connection writes to
+      ** the database file, it will do so using an in-memory journal.
+      */
+      int bDelete = !pPager->tempFile;
+      assert( sqlite3JournalIsInMemory(pPager->jfd)==0 );
+      assert( pPager->journalMode==PAGER_JOURNALMODE_DELETE
+           || pPager->journalMode==PAGER_JOURNALMODE_MEMORY
+           || pPager->journalMode==PAGER_JOURNALMODE_WAL
+      );
+      sqlite3OsClose(pPager->jfd);
+      if( bDelete ){
+        rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, pPager->extraSync);
+      }
+    }
+  }
+
+#ifdef SQLITE_CHECK_PAGES
+  sqlite3PcacheIterateDirty(pPager->pPCache, pager_set_pagehash);
+  if( pPager->dbSize==0 && sqlite3PcacheRefCount(pPager->pPCache)>0 ){
+    PgHdr *p = sqlite3PagerLookup(pPager, 1);
+    if( p ){
+      p->pageHash = 0;
+      sqlite3PagerUnrefNotNull(p);
+    }
+  }
+#endif
+
+  sqlite3BitvecDestroy(pPager->pInJournal);
+  pPager->pInJournal = 0;
+  pPager->nRec = 0;
+  if( rc==SQLITE_OK ){
+    if( MEMDB || pagerFlushOnCommit(pPager, bCommit) ){
+      sqlite3PcacheCleanAll(pPager->pPCache);
+    }else{
+      sqlite3PcacheClearWritable(pPager->pPCache);
+    }
+    sqlite3PcacheTruncate(pPager->pPCache, pPager->dbSize);
+  }
+
+  if( pagerUseWal(pPager) ){
+    /* Drop the WAL write-lock, if any. Also, if the connection was in
+    ** locking_mode=exclusive mode but is no longer, drop the EXCLUSIVE
+    ** lock held on the database file.
+    */
+    rc2 = sqlite3WalEndWriteTransaction(pPager->pWal);
+    assert( rc2==SQLITE_OK );
+  }else if( rc==SQLITE_OK && bCommit && pPager->dbFileSize>pPager->dbSize ){
+    /* This branch is taken when committing a transaction in rollback-journal
+    ** mode if the database file on disk is larger than the database image.
+    ** At this point the journal has been finalized and the transaction
+    ** successfully committed, but the EXCLUSIVE lock is still held on the
+    ** file. So it is safe to truncate the database file to its minimum
+    ** required size.  */
+    assert( pPager->eLock==EXCLUSIVE_LOCK );
+    rc = pager_truncate(pPager, pPager->dbSize);
+  }
+
+  if( rc==SQLITE_OK && bCommit ){
+    rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_COMMIT_PHASETWO, 0);
+    if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+  }
+
+  if( !pPager->exclusiveMode
+   && (!pagerUseWal(pPager) || sqlite3WalExclusiveMode(pPager->pWal, 0))
+  ){
+    rc2 = pagerUnlockDb(pPager, SHARED_LOCK);
+  }
+  pPager->eState = PAGER_READER;
+  pPager->setSuper = 0;
+
+  return (rc==SQLITE_OK?rc2:rc);
+}
+
+/* Forward reference */
+static int pager_playback(Pager *pPager, int isHot);
+
+/*
+** Execute a rollback if a transaction is active and unlock the
+** database file.
+**
+** If the pager has already entered the ERROR state, do not attempt
+** the rollback at this time. Instead, pager_unlock() is called. The
+** call to pager_unlock() will discard all in-memory pages, unlock
+** the database file and move the pager back to OPEN state. If this
+** means that there is a hot-journal left in the file-system, the next
+** connection to obtain a shared lock on the pager (which may be this one)
+** will roll it back.
+**
+** If the pager has not already entered the ERROR state, but an IO or
+** malloc error occurs during a rollback, then this will itself cause
+** the pager to enter the ERROR state. Which will be cleared by the
+** call to pager_unlock(), as described above.
+*/
+static void pagerUnlockAndRollback(Pager *pPager){
+  if( pPager->eState!=PAGER_ERROR && pPager->eState!=PAGER_OPEN ){
+    assert( assert_pager_state(pPager) );
+    if( pPager->eState>=PAGER_WRITER_LOCKED ){
+      sqlite3BeginBenignMalloc();
+      sqlite3PagerRollback(pPager);
+      sqlite3EndBenignMalloc();
+    }else if( !pPager->exclusiveMode ){
+      assert( pPager->eState==PAGER_READER );
+      pager_end_transaction(pPager, 0, 0);
+    }
+  }else if( pPager->eState==PAGER_ERROR
+         && pPager->journalMode==PAGER_JOURNALMODE_MEMORY
+         && isOpen(pPager->jfd)
+  ){
+    /* Special case for a ROLLBACK due to I/O error with an in-memory
+    ** journal:  We have to rollback immediately, before the journal is
+    ** closed, because once it is closed, all content is forgotten. */
+    int errCode = pPager->errCode;
+    u8 eLock = pPager->eLock;
+    pPager->eState = PAGER_OPEN;
+    pPager->errCode = SQLITE_OK;
+    pPager->eLock = EXCLUSIVE_LOCK;
+    pager_playback(pPager, 1);
+    pPager->errCode = errCode;
+    pPager->eLock = eLock;
+  }
+  pager_unlock(pPager);
+}
+
+/*
+** Parameter aData must point to a buffer of pPager->pageSize bytes
+** of data. Compute and return a checksum based on the contents of the
+** page of data and the current value of pPager->cksumInit.
+**
+** This is not a real checksum. It is really just the sum of the
+** random initial value (pPager->cksumInit) and every 200th byte
+** of the page data, starting with byte offset (pPager->pageSize%200).
+** Each byte is interpreted as an 8-bit unsigned integer.
+**
+** Changing the formula used to compute this checksum results in an
+** incompatible journal file format.
+**
+** If journal corruption occurs due to a power failure, the most likely
+** scenario is that one end or the other of the record will be changed.
+** It is much less likely that the two ends of the journal record will be
+** correct and the middle be corrupt.  Thus, this "checksum" scheme,
+** though fast and simple, catches the mostly likely kind of corruption.
+*/
+static u32 pager_cksum(Pager *pPager, const u8 *aData){
+  u32 cksum = pPager->cksumInit;         /* Checksum value to return */
+  int i = pPager->pageSize-200;          /* Loop counter */
+  while( i>0 ){
+    cksum += aData[i];
+    i -= 200;
+  }
+  return cksum;
+}
+
+/*
+** Read a single page from either the journal file (if isMainJrnl==1) or
+** from the sub-journal (if isMainJrnl==0) and playback that page.
+** The page begins at offset *pOffset into the file. The *pOffset
+** value is increased to the start of the next page in the journal.
+**
+** The main rollback journal uses checksums - the statement journal does
+** not.
+**
+** If the page number of the page record read from the (sub-)journal file
+** is greater than the current value of Pager.dbSize, then playback is
+** skipped and SQLITE_OK is returned.
+**
+** If pDone is not NULL, then it is a record of pages that have already
+** been played back.  If the page at *pOffset has already been played back
+** (if the corresponding pDone bit is set) then skip the playback.
+** Make sure the pDone bit corresponding to the *pOffset page is set
+** prior to returning.
+**
+** If the page record is successfully read from the (sub-)journal file
+** and played back, then SQLITE_OK is returned. If an IO error occurs
+** while reading the record from the (sub-)journal file or while writing
+** to the database file, then the IO error code is returned. If data
+** is successfully read from the (sub-)journal file but appears to be
+** corrupted, SQLITE_DONE is returned. Data is considered corrupted in
+** two circumstances:
+**
+**   * If the record page-number is illegal (0 or PAGER_SJ_PGNO), or
+**   * If the record is being rolled back from the main journal file
+**     and the checksum field does not match the record content.
+**
+** Neither of these two scenarios are possible during a savepoint rollback.
+**
+** If this is a savepoint rollback, then memory may have to be dynamically
+** allocated by this function. If this is the case and an allocation fails,
+** SQLITE_NOMEM is returned.
+*/
+static int pager_playback_one_page(
+  Pager *pPager,                /* The pager being played back */
+  i64 *pOffset,                 /* Offset of record to playback */
+  Bitvec *pDone,                /* Bitvec of pages already played back */
+  int isMainJrnl,               /* 1 -> main journal. 0 -> sub-journal. */
+  int isSavepnt                 /* True for a savepoint rollback */
+){
+  int rc;
+  PgHdr *pPg;                   /* An existing page in the cache */
+  Pgno pgno;                    /* The page number of a page in journal */
+  u32 cksum;                    /* Checksum used for sanity checking */
+  char *aData;                  /* Temporary storage for the page */
+  sqlite3_file *jfd;            /* The file descriptor for the journal file */
+  int isSynced;                 /* True if journal page is synced */
+
+  assert( (isMainJrnl&~1)==0 );      /* isMainJrnl is 0 or 1 */
+  assert( (isSavepnt&~1)==0 );       /* isSavepnt is 0 or 1 */
+  assert( isMainJrnl || pDone );     /* pDone always used on sub-journals */
+  assert( isSavepnt || pDone==0 );   /* pDone never used on non-savepoint */
+
+  aData = pPager->pTmpSpace;
+  assert( aData );         /* Temp storage must have already been allocated */
+  assert( pagerUseWal(pPager)==0 || (!isMainJrnl && isSavepnt) );
+
+  /* Either the state is greater than PAGER_WRITER_CACHEMOD (a transaction
+  ** or savepoint rollback done at the request of the caller) or this is
+  ** a hot-journal rollback. If it is a hot-journal rollback, the pager
+  ** is in state OPEN and holds an EXCLUSIVE lock. Hot-journal rollback
+  ** only reads from the main journal, not the sub-journal.
+  */
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD
+       || (pPager->eState==PAGER_OPEN && pPager->eLock==EXCLUSIVE_LOCK)
+  );
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD || isMainJrnl );
+
+  /* Read the page number and page data from the journal or sub-journal
+  ** file. Return an error code to the caller if an IO error occurs.
+  */
+  jfd = isMainJrnl ? pPager->jfd : pPager->sjfd;
+  rc = read32bits(jfd, *pOffset, &pgno);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = sqlite3OsRead(jfd, (u8*)aData, pPager->pageSize, (*pOffset)+4);
+  if( rc!=SQLITE_OK ) return rc;
+  *pOffset += pPager->pageSize + 4 + isMainJrnl*4;
+
+  /* Sanity checking on the page.  This is more important that I originally
+  ** thought.  If a power failure occurs while the journal is being written,
+  ** it could cause invalid data to be written into the journal.  We need to
+  ** detect this invalid data (with high probability) and ignore it.
+  */
+  if( pgno==0 || pgno==PAGER_SJ_PGNO(pPager) ){
+    assert( !isSavepnt );
+    return SQLITE_DONE;
+  }
+  if( pgno>(Pgno)pPager->dbSize || sqlite3BitvecTest(pDone, pgno) ){
+    return SQLITE_OK;
+  }
+  if( isMainJrnl ){
+    rc = read32bits(jfd, (*pOffset)-4, &cksum);
+    if( rc ) return rc;
+    if( !isSavepnt && pager_cksum(pPager, (u8*)aData)!=cksum ){
+      return SQLITE_DONE;
+    }
+  }
+
+  /* If this page has already been played back before during the current
+  ** rollback, then don't bother to play it back again.
+  */
+  if( pDone && (rc = sqlite3BitvecSet(pDone, pgno))!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* When playing back page 1, restore the nReserve setting
+  */
+  if( pgno==1 && pPager->nReserve!=((u8*)aData)[20] ){
+    pPager->nReserve = ((u8*)aData)[20];
+  }
+
+  /* If the pager is in CACHEMOD state, then there must be a copy of this
+  ** page in the pager cache. In this case just update the pager cache,
+  ** not the database file. The page is left marked dirty in this case.
+  **
+  ** An exception to the above rule: If the database is in no-sync mode
+  ** and a page is moved during an incremental vacuum then the page may
+  ** not be in the pager cache. Later: if a malloc() or IO error occurs
+  ** during a Movepage() call, then the page may not be in the cache
+  ** either. So the condition described in the above paragraph is not
+  ** assert()able.
+  **
+  ** If in WRITER_DBMOD, WRITER_FINISHED or OPEN state, then we update the
+  ** pager cache if it exists and the main file. The page is then marked
+  ** not dirty. Since this code is only executed in PAGER_OPEN state for
+  ** a hot-journal rollback, it is guaranteed that the page-cache is empty
+  ** if the pager is in OPEN state.
+  **
+  ** Ticket #1171:  The statement journal might contain page content that is
+  ** different from the page content at the start of the transaction.
+  ** This occurs when a page is changed prior to the start of a statement
+  ** then changed again within the statement.  When rolling back such a
+  ** statement we must not write to the original database unless we know
+  ** for certain that original page contents are synced into the main rollback
+  ** journal.  Otherwise, a power loss might leave modified data in the
+  ** database file without an entry in the rollback journal that can
+  ** restore the database to its original form.  Two conditions must be
+  ** met before writing to the database files. (1) the database must be
+  ** locked.  (2) we know that the original page content is fully synced
+  ** in the main journal either because the page is not in cache or else
+  ** the page is marked as needSync==0.
+  **
+  ** 2008-04-14:  When attempting to vacuum a corrupt database file, it
+  ** is possible to fail a statement on a database that does not yet exist.
+  ** Do not attempt to write if database file has never been opened.
+  */
+  if( pagerUseWal(pPager) ){
+    pPg = 0;
+  }else{
+    pPg = sqlite3PagerLookup(pPager, pgno);
+  }
+  assert( pPg || !MEMDB );
+  assert( pPager->eState!=PAGER_OPEN || pPg==0 || pPager->tempFile );
+  PAGERTRACE(("PLAYBACK %d page %d hash(%08x) %s\n",
+           PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, (u8*)aData),
+           (isMainJrnl?"main-journal":"sub-journal")
+  ));
+  if( isMainJrnl ){
+    isSynced = pPager->noSync || (*pOffset <= pPager->journalHdr);
+  }else{
+    isSynced = (pPg==0 || 0==(pPg->flags & PGHDR_NEED_SYNC));
+  }
+  if( isOpen(pPager->fd)
+   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
+   && isSynced
+  ){
+    i64 ofst = (pgno-1)*(i64)pPager->pageSize;
+    testcase( !isSavepnt && pPg!=0 && (pPg->flags&PGHDR_NEED_SYNC)!=0 );
+    assert( !pagerUseWal(pPager) );
+
+    /* Write the data read from the journal back into the database file.
+    ** This is usually safe even for an encrypted database - as the data
+    ** was encrypted before it was written to the journal file. The exception
+    ** is if the data was just read from an in-memory sub-journal. In that
+    ** case it must be encrypted here before it is copied into the database
+    ** file.  */
+    rc = sqlite3OsWrite(pPager->fd, (u8 *)aData, pPager->pageSize, ofst);
+
+    if( pgno>pPager->dbFileSize ){
+      pPager->dbFileSize = pgno;
+    }
+    if( pPager->pBackup ){
+      sqlite3BackupUpdate(pPager->pBackup, pgno, (u8*)aData);
+    }
+  }else if( !isMainJrnl && pPg==0 ){
+    /* If this is a rollback of a savepoint and data was not written to
+    ** the database and the page is not in-memory, there is a potential
+    ** problem. When the page is next fetched by the b-tree layer, it
+    ** will be read from the database file, which may or may not be
+    ** current.
+    **
+    ** There are a couple of different ways this can happen. All are quite
+    ** obscure. When running in synchronous mode, this can only happen
+    ** if the page is on the free-list at the start of the transaction, then
+    ** populated, then moved using sqlite3PagerMovepage().
+    **
+    ** The solution is to add an in-memory page to the cache containing
+    ** the data just read from the sub-journal. Mark the page as dirty
+    ** and if the pager requires a journal-sync, then mark the page as
+    ** requiring a journal-sync before it is written.
+    */
+    assert( isSavepnt );
+    assert( (pPager->doNotSpill & SPILLFLAG_ROLLBACK)==0 );
+    pPager->doNotSpill |= SPILLFLAG_ROLLBACK;
+    rc = sqlite3PagerGet(pPager, pgno, &pPg, 1);
+    assert( (pPager->doNotSpill & SPILLFLAG_ROLLBACK)!=0 );
+    pPager->doNotSpill &= ~SPILLFLAG_ROLLBACK;
+    if( rc!=SQLITE_OK ) return rc;
+    sqlite3PcacheMakeDirty(pPg);
+  }
+  if( pPg ){
+    /* No page should ever be explicitly rolled back that is in use, except
+    ** for page 1 which is held in use in order to keep the lock on the
+    ** database active. However such a page may be rolled back as a result
+    ** of an internal error resulting in an automatic call to
+    ** sqlite3PagerRollback().
+    */
+    void *pData;
+    pData = pPg->pData;
+    memcpy(pData, (u8*)aData, pPager->pageSize);
+    pPager->xReiniter(pPg);
+    /* It used to be that sqlite3PcacheMakeClean(pPg) was called here.  But
+    ** that call was dangerous and had no detectable benefit since the cache
+    ** is normally cleaned by sqlite3PcacheCleanAll() after rollback and so
+    ** has been removed. */
+    pager_set_pagehash(pPg);
+
+    /* If this was page 1, then restore the value of Pager.dbFileVers.
+    ** Do this before any decoding. */
+    if( pgno==1 ){
+      memcpy(&pPager->dbFileVers, &((u8*)pData)[24],sizeof(pPager->dbFileVers));
+    }
+    sqlite3PcacheRelease(pPg);
+  }
+  return rc;
+}
+
+/*
+** Parameter zSuper is the name of a super-journal file. A single journal
+** file that referred to the super-journal file has just been rolled back.
+** This routine checks if it is possible to delete the super-journal file,
+** and does so if it is.
+**
+** Argument zSuper may point to Pager.pTmpSpace. So that buffer is not
+** available for use within this function.
+**
+** When a super-journal file is created, it is populated with the names
+** of all of its child journals, one after another, formatted as utf-8
+** encoded text. The end of each child journal file is marked with a
+** nul-terminator byte (0x00). i.e. the entire contents of a super-journal
+** file for a transaction involving two databases might be:
+**
+**   "/home/bill/a.db-journal\x00/home/bill/b.db-journal\x00"
+**
+** A super-journal file may only be deleted once all of its child
+** journals have been rolled back.
+**
+** This function reads the contents of the super-journal file into
+** memory and loops through each of the child journal names. For
+** each child journal, it checks if:
+**
+**   * if the child journal exists, and if so
+**   * if the child journal contains a reference to super-journal
+**     file zSuper
+**
+** If a child journal can be found that matches both of the criteria
+** above, this function returns without doing anything. Otherwise, if
+** no such child journal can be found, file zSuper is deleted from
+** the file-system using sqlite3OsDelete().
+**
+** If an IO error within this function, an error code is returned. This
+** function allocates memory by calling sqlite3Malloc(). If an allocation
+** fails, SQLITE_NOMEM is returned. Otherwise, if no IO or malloc errors
+** occur, SQLITE_OK is returned.
+**
+** TODO: This function allocates a single block of memory to load
+** the entire contents of the super-journal file. This could be
+** a couple of kilobytes or so - potentially larger than the page
+** size.
+*/
+static int pager_delsuper(Pager *pPager, const char *zSuper){
+  sqlite3_vfs *pVfs = pPager->pVfs;
+  int rc;                   /* Return code */
+  sqlite3_file *pSuper;     /* Malloc'd super-journal file descriptor */
+  sqlite3_file *pJournal;   /* Malloc'd child-journal file descriptor */
+  char *zSuperJournal = 0;  /* Contents of super-journal file */
+  i64 nSuperJournal;        /* Size of super-journal file */
+  char *zJournal;           /* Pointer to one journal within MJ file */
+  char *zSuperPtr;          /* Space to hold super-journal filename */
+  char *zFree = 0;          /* Free this buffer */
+  int nSuperPtr;            /* Amount of space allocated to zSuperPtr[] */
+
+  /* Allocate space for both the pJournal and pSuper file descriptors.
+  ** If successful, open the super-journal file for reading.
+  */
+  pSuper = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile * 2);
+  if( !pSuper ){
+    rc = SQLITE_NOMEM_BKPT;
+    pJournal = 0;
+  }else{
+    const int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_SUPER_JOURNAL);
+    rc = sqlite3OsOpen(pVfs, zSuper, pSuper, flags, 0);
+    pJournal = (sqlite3_file *)(((u8 *)pSuper) + pVfs->szOsFile);
+  }
+  if( rc!=SQLITE_OK ) goto delsuper_out;
+
+  /* Load the entire super-journal file into space obtained from
+  ** sqlite3_malloc() and pointed to by zSuperJournal.   Also obtain
+  ** sufficient space (in zSuperPtr) to hold the names of super-journal
+  ** files extracted from regular rollback-journals.
+  */
+  rc = sqlite3OsFileSize(pSuper, &nSuperJournal);
+  if( rc!=SQLITE_OK ) goto delsuper_out;
+  nSuperPtr = pVfs->mxPathname+1;
+  zFree = sqlite3Malloc(4 + nSuperJournal + nSuperPtr + 2);
+  if( !zFree ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto delsuper_out;
+  }
+  zFree[0] = zFree[1] = zFree[2] = zFree[3] = 0;
+  zSuperJournal = &zFree[4];
+  zSuperPtr = &zSuperJournal[nSuperJournal+2];
+  rc = sqlite3OsRead(pSuper, zSuperJournal, (int)nSuperJournal, 0);
+  if( rc!=SQLITE_OK ) goto delsuper_out;
+  zSuperJournal[nSuperJournal] = 0;
+  zSuperJournal[nSuperJournal+1] = 0;
+
+  zJournal = zSuperJournal;
+  while( (zJournal-zSuperJournal)<nSuperJournal ){
+    int exists;
+    rc = sqlite3OsAccess(pVfs, zJournal, SQLITE_ACCESS_EXISTS, &exists);
+    if( rc!=SQLITE_OK ){
+      goto delsuper_out;
+    }
+    if( exists ){
+      /* One of the journals pointed to by the super-journal exists.
+      ** Open it and check if it points at the super-journal. If
+      ** so, return without deleting the super-journal file.
+      ** NB:  zJournal is really a MAIN_JOURNAL.  But call it a
+      ** SUPER_JOURNAL here so that the VFS will not send the zJournal
+      ** name into sqlite3_database_file_object().
+      */
+      int c;
+      int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_SUPER_JOURNAL);
+      rc = sqlite3OsOpen(pVfs, zJournal, pJournal, flags, 0);
+      if( rc!=SQLITE_OK ){
+        goto delsuper_out;
+      }
+
+      rc = readSuperJournal(pJournal, zSuperPtr, nSuperPtr);
+      sqlite3OsClose(pJournal);
+      if( rc!=SQLITE_OK ){
+        goto delsuper_out;
+      }
+
+      c = zSuperPtr[0]!=0 && strcmp(zSuperPtr, zSuper)==0;
+      if( c ){
+        /* We have a match. Do not delete the super-journal file. */
+        goto delsuper_out;
+      }
+    }
+    zJournal += (sqlite3Strlen30(zJournal)+1);
+  }
+
+  sqlite3OsClose(pSuper);
+  rc = sqlite3OsDelete(pVfs, zSuper, 0);
+
+delsuper_out:
+  sqlite3_free(zFree);
+  if( pSuper ){
+    sqlite3OsClose(pSuper);
+    assert( !isOpen(pJournal) );
+    sqlite3_free(pSuper);
+  }
+  return rc;
+}
+
+
+/*
+** This function is used to change the actual size of the database
+** file in the file-system. This only happens when committing a transaction,
+** or rolling back a transaction (including rolling back a hot-journal).
+**
+** If the main database file is not open, or the pager is not in either
+** DBMOD or OPEN state, this function is a no-op. Otherwise, the size
+** of the file is changed to nPage pages (nPage*pPager->pageSize bytes).
+** If the file on disk is currently larger than nPage pages, then use the VFS
+** xTruncate() method to truncate it.
+**
+** Or, it might be the case that the file on disk is smaller than
+** nPage pages. Some operating system implementations can get confused if
+** you try to truncate a file to some size that is larger than it
+** currently is, so detect this case and write a single zero byte to
+** the end of the new file instead.
+**
+** If successful, return SQLITE_OK. If an IO error occurs while modifying
+** the database file, return the error code to the caller.
+*/
+static int pager_truncate(Pager *pPager, Pgno nPage){
+  int rc = SQLITE_OK;
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( pPager->eState!=PAGER_READER );
+  PAGERTRACE(("Truncate %d npage %u\n", PAGERID(pPager), nPage));
+
+
+  if( isOpen(pPager->fd)
+   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
+  ){
+    i64 currentSize, newSize;
+    int szPage = pPager->pageSize;
+    assert( pPager->eLock==EXCLUSIVE_LOCK );
+    /* TODO: Is it safe to use Pager.dbFileSize here? */
+    rc = sqlite3OsFileSize(pPager->fd, ¤tSize);
+    newSize = szPage*(i64)nPage;
+    if( rc==SQLITE_OK && currentSize!=newSize ){
+      if( currentSize>newSize ){
+        rc = sqlite3OsTruncate(pPager->fd, newSize);
+      }else if( (currentSize+szPage)<=newSize ){
+        char *pTmp = pPager->pTmpSpace;
+        memset(pTmp, 0, szPage);
+        testcase( (newSize-szPage) == currentSize );
+        testcase( (newSize-szPage) >  currentSize );
+        sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &newSize);
+        rc = sqlite3OsWrite(pPager->fd, pTmp, szPage, newSize-szPage);
+      }
+      if( rc==SQLITE_OK ){
+        pPager->dbFileSize = nPage;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Return a sanitized version of the sector-size of OS file pFile. The
+** return value is guaranteed to lie between 32 and MAX_SECTOR_SIZE.
+*/
+SQLITE_PRIVATE int sqlite3SectorSize(sqlite3_file *pFile){
+  int iRet = sqlite3OsSectorSize(pFile);
+  if( iRet<32 ){
+    iRet = 512;
+  }else if( iRet>MAX_SECTOR_SIZE ){
+    assert( MAX_SECTOR_SIZE>=512 );
+    iRet = MAX_SECTOR_SIZE;
+  }
+  return iRet;
+}
+
+/*
+** Set the value of the Pager.sectorSize variable for the given
+** pager based on the value returned by the xSectorSize method
+** of the open database file. The sector size will be used
+** to determine the size and alignment of journal header and
+** super-journal pointers within created journal files.
+**
+** For temporary files the effective sector size is always 512 bytes.
+**
+** Otherwise, for non-temporary files, the effective sector size is
+** the value returned by the xSectorSize() method rounded up to 32 if
+** it is less than 32, or rounded down to MAX_SECTOR_SIZE if it
+** is greater than MAX_SECTOR_SIZE.
+**
+** If the file has the SQLITE_IOCAP_POWERSAFE_OVERWRITE property, then set
+** the effective sector size to its minimum value (512).  The purpose of
+** pPager->sectorSize is to define the "blast radius" of bytes that
+** might change if a crash occurs while writing to a single byte in
+** that range.  But with POWERSAFE_OVERWRITE, the blast radius is zero
+** (that is what POWERSAFE_OVERWRITE means), so we minimize the sector
+** size.  For backwards compatibility of the rollback journal file format,
+** we cannot reduce the effective sector size below 512.
+*/
+static void setSectorSize(Pager *pPager){
+  assert( isOpen(pPager->fd) || pPager->tempFile );
+
+  if( pPager->tempFile
+   || (sqlite3OsDeviceCharacteristics(pPager->fd) &
+              SQLITE_IOCAP_POWERSAFE_OVERWRITE)!=0
+  ){
+    /* Sector size doesn't matter for temporary files. Also, the file
+    ** may not have been opened yet, in which case the OsSectorSize()
+    ** call will segfault. */
+    pPager->sectorSize = 512;
+  }else{
+    pPager->sectorSize = sqlite3SectorSize(pPager->fd);
+  }
+}
+
+/*
+** Playback the journal and thus restore the database file to
+** the state it was in before we started making changes.
+**
+** The journal file format is as follows:
+**
+**  (1)  8 byte prefix.  A copy of aJournalMagic[].
+**  (2)  4 byte big-endian integer which is the number of valid page records
+**       in the journal.  If this value is 0xffffffff, then compute the
+**       number of page records from the journal size.
+**  (3)  4 byte big-endian integer which is the initial value for the
+**       sanity checksum.
+**  (4)  4 byte integer which is the number of pages to truncate the
+**       database to during a rollback.
+**  (5)  4 byte big-endian integer which is the sector size.  The header
+**       is this many bytes in size.
+**  (6)  4 byte big-endian integer which is the page size.
+**  (7)  zero padding out to the next sector size.
+**  (8)  Zero or more pages instances, each as follows:
+**        +  4 byte page number.
+**        +  pPager->pageSize bytes of data.
+**        +  4 byte checksum
+**
+** When we speak of the journal header, we mean the first 7 items above.
+** Each entry in the journal is an instance of the 8th item.
+**
+** Call the value from the second bullet "nRec".  nRec is the number of
+** valid page entries in the journal.  In most cases, you can compute the
+** value of nRec from the size of the journal file.  But if a power
+** failure occurred while the journal was being written, it could be the
+** case that the size of the journal file had already been increased but
+** the extra entries had not yet made it safely to disk.  In such a case,
+** the value of nRec computed from the file size would be too large.  For
+** that reason, we always use the nRec value in the header.
+**
+** If the nRec value is 0xffffffff it means that nRec should be computed
+** from the file size.  This value is used when the user selects the
+** no-sync option for the journal.  A power failure could lead to corruption
+** in this case.  But for things like temporary table (which will be
+** deleted when the power is restored) we don't care.
+**
+** If the file opened as the journal file is not a well-formed
+** journal file then all pages up to the first corrupted page are rolled
+** back (or no pages if the journal header is corrupted). The journal file
+** is then deleted and SQLITE_OK returned, just as if no corruption had
+** been encountered.
+**
+** If an I/O or malloc() error occurs, the journal-file is not deleted
+** and an error code is returned.
+**
+** The isHot parameter indicates that we are trying to rollback a journal
+** that might be a hot journal.  Or, it could be that the journal is
+** preserved because of JOURNALMODE_PERSIST or JOURNALMODE_TRUNCATE.
+** If the journal really is hot, reset the pager cache prior rolling
+** back any content.  If the journal is merely persistent, no reset is
+** needed.
+*/
+static int pager_playback(Pager *pPager, int isHot){
+  sqlite3_vfs *pVfs = pPager->pVfs;
+  i64 szJ;                 /* Size of the journal file in bytes */
+  u32 nRec;                /* Number of Records in the journal */
+  u32 u;                   /* Unsigned loop counter */
+  Pgno mxPg = 0;           /* Size of the original file in pages */
+  int rc;                  /* Result code of a subroutine */
+  int res = 1;             /* Value returned by sqlite3OsAccess() */
+  char *zSuper = 0;        /* Name of super-journal file if any */
+  int needPagerReset;      /* True to reset page prior to first page rollback */
+  int nPlayback = 0;       /* Total number of pages restored from journal */
+  u32 savedPageSize = pPager->pageSize;
+
+  /* Figure out how many records are in the journal.  Abort early if
+  ** the journal is empty.
+  */
+  assert( isOpen(pPager->jfd) );
+  rc = sqlite3OsFileSize(pPager->jfd, &szJ);
+  if( rc!=SQLITE_OK ){
+    goto end_playback;
+  }
+
+  /* Read the super-journal name from the journal, if it is present.
+  ** If a super-journal file name is specified, but the file is not
+  ** present on disk, then the journal is not hot and does not need to be
+  ** played back.
+  **
+  ** TODO: Technically the following is an error because it assumes that
+  ** buffer Pager.pTmpSpace is (mxPathname+1) bytes or larger. i.e. that
+  ** (pPager->pageSize >= pPager->pVfs->mxPathname+1). Using os_unix.c,
+  ** mxPathname is 512, which is the same as the minimum allowable value
+  ** for pageSize.
+  */
+  zSuper = pPager->pTmpSpace;
+  rc = readSuperJournal(pPager->jfd, zSuper, pPager->pVfs->mxPathname+1);
+  if( rc==SQLITE_OK && zSuper[0] ){
+    rc = sqlite3OsAccess(pVfs, zSuper, SQLITE_ACCESS_EXISTS, &res);
+  }
+  zSuper = 0;
+  if( rc!=SQLITE_OK || !res ){
+    goto end_playback;
+  }
+  pPager->journalOff = 0;
+  needPagerReset = isHot;
+
+  /* This loop terminates either when a readJournalHdr() or
+  ** pager_playback_one_page() call returns SQLITE_DONE or an IO error
+  ** occurs.
+  */
+  while( 1 ){
+    /* Read the next journal header from the journal file.  If there are
+    ** not enough bytes left in the journal file for a complete header, or
+    ** it is corrupted, then a process must have failed while writing it.
+    ** This indicates nothing more needs to be rolled back.
+    */
+    rc = readJournalHdr(pPager, isHot, szJ, &nRec, &mxPg);
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_DONE ){
+        rc = SQLITE_OK;
+      }
+      goto end_playback;
+    }
+
+    /* If nRec is 0xffffffff, then this journal was created by a process
+    ** working in no-sync mode. This means that the rest of the journal
+    ** file consists of pages, there are no more journal headers. Compute
+    ** the value of nRec based on this assumption.
+    */
+    if( nRec==0xffffffff ){
+      assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
+      nRec = (int)((szJ - JOURNAL_HDR_SZ(pPager))/JOURNAL_PG_SZ(pPager));
+    }
+
+    /* If nRec is 0 and this rollback is of a transaction created by this
+    ** process and if this is the final header in the journal, then it means
+    ** that this part of the journal was being filled but has not yet been
+    ** synced to disk.  Compute the number of pages based on the remaining
+    ** size of the file.
+    **
+    ** The third term of the test was added to fix ticket #2565.
+    ** When rolling back a hot journal, nRec==0 always means that the next
+    ** chunk of the journal contains zero pages to be rolled back.  But
+    ** when doing a ROLLBACK and the nRec==0 chunk is the last chunk in
+    ** the journal, it means that the journal might contain additional
+    ** pages that need to be rolled back and that the number of pages
+    ** should be computed based on the journal file size.
+    */
+    if( nRec==0 && !isHot &&
+        pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff ){
+      nRec = (int)((szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager));
+    }
+
+    /* If this is the first header read from the journal, truncate the
+    ** database file back to its original size.
+    */
+    if( pPager->journalOff==JOURNAL_HDR_SZ(pPager) ){
+      rc = pager_truncate(pPager, mxPg);
+      if( rc!=SQLITE_OK ){
+        goto end_playback;
+      }
+      pPager->dbSize = mxPg;
+      if( pPager->mxPgno<mxPg ){
+        pPager->mxPgno = mxPg;
+      }
+    }
+
+    /* Copy original pages out of the journal and back into the
+    ** database file and/or page cache.
+    */
+    for(u=0; u<nRec; u++){
+      if( needPagerReset ){
+        pager_reset(pPager);
+        needPagerReset = 0;
+      }
+      rc = pager_playback_one_page(pPager,&pPager->journalOff,0,1,0);
+      if( rc==SQLITE_OK ){
+        nPlayback++;
+      }else{
+        if( rc==SQLITE_DONE ){
+          pPager->journalOff = szJ;
+          break;
+        }else if( rc==SQLITE_IOERR_SHORT_READ ){
+          /* If the journal has been truncated, simply stop reading and
+          ** processing the journal. This might happen if the journal was
+          ** not completely written and synced prior to a crash.  In that
+          ** case, the database should have never been written in the
+          ** first place so it is OK to simply abandon the rollback. */
+          rc = SQLITE_OK;
+          goto end_playback;
+        }else{
+          /* If we are unable to rollback, quit and return the error
+          ** code.  This will cause the pager to enter the error state
+          ** so that no further harm will be done.  Perhaps the next
+          ** process to come along will be able to rollback the database.
+          */
+          goto end_playback;
+        }
+      }
+    }
+  }
+  /*NOTREACHED*/
+  assert( 0 );
+
+end_playback:
+  if( rc==SQLITE_OK ){
+    rc = sqlite3PagerSetPagesize(pPager, &savedPageSize, -1);
+  }
+  /* Following a rollback, the database file should be back in its original
+  ** state prior to the start of the transaction, so invoke the
+  ** SQLITE_FCNTL_DB_UNCHANGED file-control method to disable the
+  ** assertion that the transaction counter was modified.
+  */
+#ifdef SQLITE_DEBUG
+  sqlite3OsFileControlHint(pPager->fd,SQLITE_FCNTL_DB_UNCHANGED,0);
+#endif
+
+  /* If this playback is happening automatically as a result of an IO or
+  ** malloc error that occurred after the change-counter was updated but
+  ** before the transaction was committed, then the change-counter
+  ** modification may just have been reverted. If this happens in exclusive
+  ** mode, then subsequent transactions performed by the connection will not
+  ** update the change-counter at all. This may lead to cache inconsistency
+  ** problems for other processes at some point in the future. So, just
+  ** in case this has happened, clear the changeCountDone flag now.
+  */
+  pPager->changeCountDone = pPager->tempFile;
+
+  if( rc==SQLITE_OK ){
+    /* Leave 4 bytes of space before the super-journal filename in memory.
+    ** This is because it may end up being passed to sqlite3OsOpen(), in
+    ** which case it requires 4 0x00 bytes in memory immediately before
+    ** the filename. */
+    zSuper = &pPager->pTmpSpace[4];
+    rc = readSuperJournal(pPager->jfd, zSuper, pPager->pVfs->mxPathname+1);
+    testcase( rc!=SQLITE_OK );
+  }
+  if( rc==SQLITE_OK
+   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
+  ){
+    rc = sqlite3PagerSync(pPager, 0);
+  }
+  if( rc==SQLITE_OK ){
+    rc = pager_end_transaction(pPager, zSuper[0]!='\0', 0);
+    testcase( rc!=SQLITE_OK );
+  }
+  if( rc==SQLITE_OK && zSuper[0] && res ){
+    /* If there was a super-journal and this routine will return success,
+    ** see if it is possible to delete the super-journal.
+    */
+    assert( zSuper==&pPager->pTmpSpace[4] );
+    memset(pPager->pTmpSpace, 0, 4);
+    rc = pager_delsuper(pPager, zSuper);
+    testcase( rc!=SQLITE_OK );
+  }
+  if( isHot && nPlayback ){
+    sqlite3_log(SQLITE_NOTICE_RECOVER_ROLLBACK, "recovered %d pages from %s",
+                nPlayback, pPager->zJournal);
+  }
+
+  /* The Pager.sectorSize variable may have been updated while rolling
+  ** back a journal created by a process with a different sector size
+  ** value. Reset it to the correct value for this process.
+  */
+  setSectorSize(pPager);
+  return rc;
+}
+
+
+/*
+** Read the content for page pPg out of the database file (or out of
+** the WAL if that is where the most recent copy if found) into
+** pPg->pData. A shared lock or greater must be held on the database
+** file before this function is called.
+**
+** If page 1 is read, then the value of Pager.dbFileVers[] is set to
+** the value read from the database file.
+**
+** If an IO error occurs, then the IO error is returned to the caller.
+** Otherwise, SQLITE_OK is returned.
+*/
+static int readDbPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager; /* Pager object associated with page pPg */
+  int rc = SQLITE_OK;          /* Return code */
+
+#ifndef SQLITE_OMIT_WAL
+  u32 iFrame = 0;              /* Frame of WAL containing pgno */
+
+  assert( pPager->eState>=PAGER_READER && !MEMDB );
+  assert( isOpen(pPager->fd) );
+
+  if( pagerUseWal(pPager) ){
+    rc = sqlite3WalFindFrame(pPager->pWal, pPg->pgno, &iFrame);
+    if( rc ) return rc;
+  }
+  if( iFrame ){
+    rc = sqlite3WalReadFrame(pPager->pWal, iFrame,pPager->pageSize,pPg->pData);
+  }else
+#endif
+  {
+    i64 iOffset = (pPg->pgno-1)*(i64)pPager->pageSize;
+    rc = sqlite3OsRead(pPager->fd, pPg->pData, pPager->pageSize, iOffset);
+    if( rc==SQLITE_IOERR_SHORT_READ ){
+      rc = SQLITE_OK;
+    }
+  }
+
+  if( pPg->pgno==1 ){
+    if( rc ){
+      /* If the read is unsuccessful, set the dbFileVers[] to something
+      ** that will never be a valid file version.  dbFileVers[] is a copy
+      ** of bytes 24..39 of the database.  Bytes 28..31 should always be
+      ** zero or the size of the database in page. Bytes 32..35 and 35..39
+      ** should be page numbers which are never 0xffffffff.  So filling
+      ** pPager->dbFileVers[] with all 0xff bytes should suffice.
+      **
+      ** For an encrypted database, the situation is more complex:  bytes
+      ** 24..39 of the database are white noise.  But the probability of
+      ** white noise equaling 16 bytes of 0xff is vanishingly small so
+      ** we should still be ok.
+      */
+      memset(pPager->dbFileVers, 0xff, sizeof(pPager->dbFileVers));
+    }else{
+      u8 *dbFileVers = &((u8*)pPg->pData)[24];
+      memcpy(&pPager->dbFileVers, dbFileVers, sizeof(pPager->dbFileVers));
+    }
+  }
+  PAGER_INCR(sqlite3_pager_readdb_count);
+  PAGER_INCR(pPager->nRead);
+  IOTRACE(("PGIN %p %d\n", pPager, pPg->pgno));
+  PAGERTRACE(("FETCH %d page %d hash(%08x)\n",
+               PAGERID(pPager), pPg->pgno, pager_pagehash(pPg)));
+
+  return rc;
+}
+
+/*
+** Update the value of the change-counter at offsets 24 and 92 in
+** the header and the sqlite version number at offset 96.
+**
+** This is an unconditional update.  See also the pager_incr_changecounter()
+** routine which only updates the change-counter if the update is actually
+** needed, as determined by the pPager->changeCountDone state variable.
+*/
+static void pager_write_changecounter(PgHdr *pPg){
+  u32 change_counter;
+  if( NEVER(pPg==0) ) return;
+
+  /* Increment the value just read and write it back to byte 24. */
+  change_counter = sqlite3Get4byte((u8*)pPg->pPager->dbFileVers)+1;
+  put32bits(((char*)pPg->pData)+24, change_counter);
+
+  /* Also store the SQLite version number in bytes 96..99 and in
+  ** bytes 92..95 store the change counter for which the version number
+  ** is valid. */
+  put32bits(((char*)pPg->pData)+92, change_counter);
+  put32bits(((char*)pPg->pData)+96, SQLITE_VERSION_NUMBER);
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** This function is invoked once for each page that has already been
+** written into the log file when a WAL transaction is rolled back.
+** Parameter iPg is the page number of said page. The pCtx argument
+** is actually a pointer to the Pager structure.
+**
+** If page iPg is present in the cache, and has no outstanding references,
+** it is discarded. Otherwise, if there are one or more outstanding
+** references, the page content is reloaded from the database. If the
+** attempt to reload content from the database is required and fails,
+** return an SQLite error code. Otherwise, SQLITE_OK.
+*/
+static int pagerUndoCallback(void *pCtx, Pgno iPg){
+  int rc = SQLITE_OK;
+  Pager *pPager = (Pager *)pCtx;
+  PgHdr *pPg;
+
+  assert( pagerUseWal(pPager) );
+  pPg = sqlite3PagerLookup(pPager, iPg);
+  if( pPg ){
+    if( sqlite3PcachePageRefcount(pPg)==1 ){
+      sqlite3PcacheDrop(pPg);
+    }else{
+      rc = readDbPage(pPg);
+      if( rc==SQLITE_OK ){
+        pPager->xReiniter(pPg);
+      }
+      sqlite3PagerUnrefNotNull(pPg);
+    }
+  }
+
+  /* Normally, if a transaction is rolled back, any backup processes are
+  ** updated as data is copied out of the rollback journal and into the
+  ** database. This is not generally possible with a WAL database, as
+  ** rollback involves simply truncating the log file. Therefore, if one
+  ** or more frames have already been written to the log (and therefore
+  ** also copied into the backup databases) as part of this transaction,
+  ** the backups must be restarted.
+  */
+  sqlite3BackupRestart(pPager->pBackup);
+
+  return rc;
+}
+
+/*
+** This function is called to rollback a transaction on a WAL database.
+*/
+static int pagerRollbackWal(Pager *pPager){
+  int rc;                         /* Return Code */
+  PgHdr *pList;                   /* List of dirty pages to revert */
+
+  /* For all pages in the cache that are currently dirty or have already
+  ** been written (but not committed) to the log file, do one of the
+  ** following:
+  **
+  **   + Discard the cached page (if refcount==0), or
+  **   + Reload page content from the database (if refcount>0).
+  */
+  pPager->dbSize = pPager->dbOrigSize;
+  rc = sqlite3WalUndo(pPager->pWal, pagerUndoCallback, (void *)pPager);
+  pList = sqlite3PcacheDirtyList(pPager->pPCache);
+  while( pList && rc==SQLITE_OK ){
+    PgHdr *pNext = pList->pDirty;
+    rc = pagerUndoCallback((void *)pPager, pList->pgno);
+    pList = pNext;
+  }
+
+  return rc;
+}
+
+/*
+** This function is a wrapper around sqlite3WalFrames(). As well as logging
+** the contents of the list of pages headed by pList (connected by pDirty),
+** this function notifies any active backup processes that the pages have
+** changed.
+**
+** The list of pages passed into this routine is always sorted by page number.
+** Hence, if page 1 appears anywhere on the list, it will be the first page.
+*/
+static int pagerWalFrames(
+  Pager *pPager,                  /* Pager object */
+  PgHdr *pList,                   /* List of frames to log */
+  Pgno nTruncate,                 /* Database size after this commit */
+  int isCommit                    /* True if this is a commit */
+){
+  int rc;                         /* Return code */
+  int nList;                      /* Number of pages in pList */
+  PgHdr *p;                       /* For looping over pages */
+
+  assert( pPager->pWal );
+  assert( pList );
+#ifdef SQLITE_DEBUG
+  /* Verify that the page list is in ascending order */
+  for(p=pList; p && p->pDirty; p=p->pDirty){
+    assert( p->pgno < p->pDirty->pgno );
+  }
+#endif
+
+  assert( pList->pDirty==0 || isCommit );
+  if( isCommit ){
+    /* If a WAL transaction is being committed, there is no point in writing
+    ** any pages with page numbers greater than nTruncate into the WAL file.
+    ** They will never be read by any client. So remove them from the pDirty
+    ** list here. */
+    PgHdr **ppNext = &pList;
+    nList = 0;
+    for(p=pList; (*ppNext = p)!=0; p=p->pDirty){
+      if( p->pgno<=nTruncate ){
+        ppNext = &p->pDirty;
+        nList++;
+      }
+    }
+    assert( pList );
+  }else{
+    nList = 1;
+  }
+  pPager->aStat[PAGER_STAT_WRITE] += nList;
+
+  if( pList->pgno==1 ) pager_write_changecounter(pList);
+  rc = sqlite3WalFrames(pPager->pWal,
+      pPager->pageSize, pList, nTruncate, isCommit, pPager->walSyncFlags
+  );
+  if( rc==SQLITE_OK && pPager->pBackup ){
+    for(p=pList; p; p=p->pDirty){
+      sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
+    }
+  }
+
+#ifdef SQLITE_CHECK_PAGES
+  pList = sqlite3PcacheDirtyList(pPager->pPCache);
+  for(p=pList; p; p=p->pDirty){
+    pager_set_pagehash(p);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** Begin a read transaction on the WAL.
+**
+** This routine used to be called "pagerOpenSnapshot()" because it essentially
+** makes a snapshot of the database at the current point in time and preserves
+** that snapshot for use by the reader in spite of concurrently changes by
+** other writers or checkpointers.
+*/
+static int pagerBeginReadTransaction(Pager *pPager){
+  int rc;                         /* Return code */
+  int changed = 0;                /* True if cache must be reset */
+
+  assert( pagerUseWal(pPager) );
+  assert( pPager->eState==PAGER_OPEN || pPager->eState==PAGER_READER );
+
+  /* sqlite3WalEndReadTransaction() was not called for the previous
+  ** transaction in locking_mode=EXCLUSIVE.  So call it now.  If we
+  ** are in locking_mode=NORMAL and EndRead() was previously called,
+  ** the duplicate call is harmless.
+  */
+  sqlite3WalEndReadTransaction(pPager->pWal);
+
+  rc = sqlite3WalBeginReadTransaction(pPager->pWal, &changed);
+  if( rc!=SQLITE_OK || changed ){
+    pager_reset(pPager);
+    if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);
+  }
+
+  return rc;
+}
+#endif
+
+/*
+** This function is called as part of the transition from PAGER_OPEN
+** to PAGER_READER state to determine the size of the database file
+** in pages (assuming the page size currently stored in Pager.pageSize).
+**
+** If no error occurs, SQLITE_OK is returned and the size of the database
+** in pages is stored in *pnPage. Otherwise, an error code (perhaps
+** SQLITE_IOERR_FSTAT) is returned and *pnPage is left unmodified.
+*/
+static int pagerPagecount(Pager *pPager, Pgno *pnPage){
+  Pgno nPage;                     /* Value to return via *pnPage */
+
+  /* Query the WAL sub-system for the database size. The WalDbsize()
+  ** function returns zero if the WAL is not open (i.e. Pager.pWal==0), or
+  ** if the database size is not available. The database size is not
+  ** available from the WAL sub-system if the log file is empty or
+  ** contains no valid committed transactions.
+  */
+  assert( pPager->eState==PAGER_OPEN );
+  assert( pPager->eLock>=SHARED_LOCK );
+  assert( isOpen(pPager->fd) );
+  assert( pPager->tempFile==0 );
+  nPage = sqlite3WalDbsize(pPager->pWal);
+
+  /* If the number of pages in the database is not available from the
+  ** WAL sub-system, determine the page count based on the size of
+  ** the database file.  If the size of the database file is not an
+  ** integer multiple of the page-size, round up the result.
+  */
+  if( nPage==0 && ALWAYS(isOpen(pPager->fd)) ){
+    i64 n = 0;                    /* Size of db file in bytes */
+    int rc = sqlite3OsFileSize(pPager->fd, &n);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    nPage = (Pgno)((n+pPager->pageSize-1) / pPager->pageSize);
+  }
+
+  /* If the current number of pages in the file is greater than the
+  ** configured maximum pager number, increase the allowed limit so
+  ** that the file can be read.
+  */
+  if( nPage>pPager->mxPgno ){
+    pPager->mxPgno = (Pgno)nPage;
+  }
+
+  *pnPage = nPage;
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** Check if the *-wal file that corresponds to the database opened by pPager
+** exists if the database is not empty, or verify that the *-wal file does
+** not exist (by deleting it) if the database file is empty.
+**
+** If the database is not empty and the *-wal file exists, open the pager
+** in WAL mode.  If the database is empty or if no *-wal file exists and
+** if no error occurs, make sure Pager.journalMode is not set to
+** PAGER_JOURNALMODE_WAL.
+**
+** Return SQLITE_OK or an error code.
+**
+** The caller must hold a SHARED lock on the database file to call this
+** function. Because an EXCLUSIVE lock on the db file is required to delete
+** a WAL on a none-empty database, this ensures there is no race condition
+** between the xAccess() below and an xDelete() being executed by some
+** other connection.
+*/
+static int pagerOpenWalIfPresent(Pager *pPager){
+  int rc = SQLITE_OK;
+  assert( pPager->eState==PAGER_OPEN );
+  assert( pPager->eLock>=SHARED_LOCK );
+
+  if( !pPager->tempFile ){
+    int isWal;                    /* True if WAL file exists */
+    rc = sqlite3OsAccess(
+        pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &isWal
+    );
+    if( rc==SQLITE_OK ){
+      if( isWal ){
+        Pgno nPage;                   /* Size of the database file */
+
+        rc = pagerPagecount(pPager, &nPage);
+        if( rc ) return rc;
+        if( nPage==0 ){
+          rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
+        }else{
+          testcase( sqlite3PcachePagecount(pPager->pPCache)==0 );
+          rc = sqlite3PagerOpenWal(pPager, 0);
+        }
+      }else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
+        pPager->journalMode = PAGER_JOURNALMODE_DELETE;
+      }
+    }
+  }
+  return rc;
+}
+#endif
+
+/*
+** Playback savepoint pSavepoint. Or, if pSavepoint==NULL, then playback
+** the entire super-journal file. The case pSavepoint==NULL occurs when
+** a ROLLBACK TO command is invoked on a SAVEPOINT that is a transaction
+** savepoint.
+**
+** When pSavepoint is not NULL (meaning a non-transaction savepoint is
+** being rolled back), then the rollback consists of up to three stages,
+** performed in the order specified:
+**
+**   * Pages are played back from the main journal starting at byte
+**     offset PagerSavepoint.iOffset and continuing to
+**     PagerSavepoint.iHdrOffset, or to the end of the main journal
+**     file if PagerSavepoint.iHdrOffset is zero.
+**
+**   * If PagerSavepoint.iHdrOffset is not zero, then pages are played
+**     back starting from the journal header immediately following
+**     PagerSavepoint.iHdrOffset to the end of the main journal file.
+**
+**   * Pages are then played back from the sub-journal file, starting
+**     with the PagerSavepoint.iSubRec and continuing to the end of
+**     the journal file.
+**
+** Throughout the rollback process, each time a page is rolled back, the
+** corresponding bit is set in a bitvec structure (variable pDone in the
+** implementation below). This is used to ensure that a page is only
+** rolled back the first time it is encountered in either journal.
+**
+** If pSavepoint is NULL, then pages are only played back from the main
+** journal file. There is no need for a bitvec in this case.
+**
+** In either case, before playback commences the Pager.dbSize variable
+** is reset to the value that it held at the start of the savepoint
+** (or transaction). No page with a page-number greater than this value
+** is played back. If one is encountered it is simply skipped.
+*/
+static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
+  i64 szJ;                 /* Effective size of the main journal */
+  i64 iHdrOff;             /* End of first segment of main-journal records */
+  int rc = SQLITE_OK;      /* Return code */
+  Bitvec *pDone = 0;       /* Bitvec to ensure pages played back only once */
+
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+
+  /* Allocate a bitvec to use to store the set of pages rolled back */
+  if( pSavepoint ){
+    pDone = sqlite3BitvecCreate(pSavepoint->nOrig);
+    if( !pDone ){
+      return SQLITE_NOMEM_BKPT;
+    }
+  }
+
+  /* Set the database size back to the value it was before the savepoint
+  ** being reverted was opened.
+  */
+  pPager->dbSize = pSavepoint ? pSavepoint->nOrig : pPager->dbOrigSize;
+  pPager->changeCountDone = pPager->tempFile;
+
+  if( !pSavepoint && pagerUseWal(pPager) ){
+    return pagerRollbackWal(pPager);
+  }
+
+  /* Use pPager->journalOff as the effective size of the main rollback
+  ** journal.  The actual file might be larger than this in
+  ** PAGER_JOURNALMODE_TRUNCATE or PAGER_JOURNALMODE_PERSIST.  But anything
+  ** past pPager->journalOff is off-limits to us.
+  */
+  szJ = pPager->journalOff;
+  assert( pagerUseWal(pPager)==0 || szJ==0 );
+
+  /* Begin by rolling back records from the main journal starting at
+  ** PagerSavepoint.iOffset and continuing to the next journal header.
+  ** There might be records in the main journal that have a page number
+  ** greater than the current database size (pPager->dbSize) but those
+  ** will be skipped automatically.  Pages are added to pDone as they
+  ** are played back.
+  */
+  if( pSavepoint && !pagerUseWal(pPager) ){
+    iHdrOff = pSavepoint->iHdrOffset ? pSavepoint->iHdrOffset : szJ;
+    pPager->journalOff = pSavepoint->iOffset;
+    while( rc==SQLITE_OK && pPager->journalOff<iHdrOff ){
+      rc = pager_playback_one_page(pPager, &pPager->journalOff, pDone, 1, 1);
+    }
+    assert( rc!=SQLITE_DONE );
+  }else{
+    pPager->journalOff = 0;
+  }
+
+  /* Continue rolling back records out of the main journal starting at
+  ** the first journal header seen and continuing until the effective end
+  ** of the main journal file.  Continue to skip out-of-range pages and
+  ** continue adding pages rolled back to pDone.
+  */
+  while( rc==SQLITE_OK && pPager->journalOff<szJ ){
+    u32 ii;            /* Loop counter */
+    u32 nJRec = 0;     /* Number of Journal Records */
+    u32 dummy;
+    rc = readJournalHdr(pPager, 0, szJ, &nJRec, &dummy);
+    assert( rc!=SQLITE_DONE );
+
+    /*
+    ** The "pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff"
+    ** test is related to ticket #2565.  See the discussion in the
+    ** pager_playback() function for additional information.
+    */
+    if( nJRec==0
+     && pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff
+    ){
+      nJRec = (u32)((szJ - pPager->journalOff)/JOURNAL_PG_SZ(pPager));
+    }
+    for(ii=0; rc==SQLITE_OK && ii<nJRec && pPager->journalOff<szJ; ii++){
+      rc = pager_playback_one_page(pPager, &pPager->journalOff, pDone, 1, 1);
+    }
+    assert( rc!=SQLITE_DONE );
+  }
+  assert( rc!=SQLITE_OK || pPager->journalOff>=szJ );
+
+  /* Finally,  rollback pages from the sub-journal.  Page that were
+  ** previously rolled back out of the main journal (and are hence in pDone)
+  ** will be skipped.  Out-of-range pages are also skipped.
+  */
+  if( pSavepoint ){
+    u32 ii;            /* Loop counter */
+    i64 offset = (i64)pSavepoint->iSubRec*(4+pPager->pageSize);
+
+    if( pagerUseWal(pPager) ){
+      rc = sqlite3WalSavepointUndo(pPager->pWal, pSavepoint->aWalData);
+    }
+    for(ii=pSavepoint->iSubRec; rc==SQLITE_OK && ii<pPager->nSubRec; ii++){
+      assert( offset==(i64)ii*(4+pPager->pageSize) );
+      rc = pager_playback_one_page(pPager, &offset, pDone, 0, 1);
+    }
+    assert( rc!=SQLITE_DONE );
+  }
+
+  sqlite3BitvecDestroy(pDone);
+  if( rc==SQLITE_OK ){
+    pPager->journalOff = szJ;
+  }
+
+  return rc;
+}
+
+/*
+** Change the maximum number of in-memory pages that are allowed
+** before attempting to recycle clean and unused pages.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
+  sqlite3PcacheSetCachesize(pPager->pPCache, mxPage);
+}
+
+/*
+** Change the maximum number of in-memory pages that are allowed
+** before attempting to spill pages to journal.
+*/
+SQLITE_PRIVATE int sqlite3PagerSetSpillsize(Pager *pPager, int mxPage){
+  return sqlite3PcacheSetSpillsize(pPager->pPCache, mxPage);
+}
+
+/*
+** Invoke SQLITE_FCNTL_MMAP_SIZE based on the current value of szMmap.
+*/
+static void pagerFixMaplimit(Pager *pPager){
+#if SQLITE_MAX_MMAP_SIZE>0
+  sqlite3_file *fd = pPager->fd;
+  if( isOpen(fd) && fd->pMethods->iVersion>=3 ){
+    sqlite3_int64 sz;
+    sz = pPager->szMmap;
+    pPager->bUseFetch = (sz>0);
+    setGetterMethod(pPager);
+    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_MMAP_SIZE, &sz);
+  }
+#endif
+}
+
+/*
+** Change the maximum size of any memory mapping made of the database file.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetMmapLimit(Pager *pPager, sqlite3_int64 szMmap){
+  pPager->szMmap = szMmap;
+  pagerFixMaplimit(pPager);
+}
+
+/*
+** Free as much memory as possible from the pager.
+*/
+SQLITE_PRIVATE void sqlite3PagerShrink(Pager *pPager){
+  sqlite3PcacheShrink(pPager->pPCache);
+}
+
+/*
+** Adjust settings of the pager to those specified in the pgFlags parameter.
+**
+** The "level" in pgFlags & PAGER_SYNCHRONOUS_MASK sets the robustness
+** of the database to damage due to OS crashes or power failures by
+** changing the number of syncs()s when writing the journals.
+** There are four levels:
+**
+**    OFF       sqlite3OsSync() is never called.  This is the default
+**              for temporary and transient files.
+**
+**    NORMAL    The journal is synced once before writes begin on the
+**              database.  This is normally adequate protection, but
+**              it is theoretically possible, though very unlikely,
+**              that an inopertune power failure could leave the journal
+**              in a state which would cause damage to the database
+**              when it is rolled back.
+**
+**    FULL      The journal is synced twice before writes begin on the
+**              database (with some additional information - the nRec field
+**              of the journal header - being written in between the two
+**              syncs).  If we assume that writing a
+**              single disk sector is atomic, then this mode provides
+**              assurance that the journal will not be corrupted to the
+**              point of causing damage to the database during rollback.
+**
+**    EXTRA     This is like FULL except that is also syncs the directory
+**              that contains the rollback journal after the rollback
+**              journal is unlinked.
+**
+** The above is for a rollback-journal mode.  For WAL mode, OFF continues
+** to mean that no syncs ever occur.  NORMAL means that the WAL is synced
+** prior to the start of checkpoint and that the database file is synced
+** at the conclusion of the checkpoint if the entire content of the WAL
+** was written back into the database.  But no sync operations occur for
+** an ordinary commit in NORMAL mode with WAL.  FULL means that the WAL
+** file is synced following each commit operation, in addition to the
+** syncs associated with NORMAL.  There is no difference between FULL
+** and EXTRA for WAL mode.
+**
+** Do not confuse synchronous=FULL with SQLITE_SYNC_FULL.  The
+** SQLITE_SYNC_FULL macro means to use the MacOSX-style full-fsync
+** using fcntl(F_FULLFSYNC).  SQLITE_SYNC_NORMAL means to do an
+** ordinary fsync() call.  There is no difference between SQLITE_SYNC_FULL
+** and SQLITE_SYNC_NORMAL on platforms other than MacOSX.  But the
+** synchronous=FULL versus synchronous=NORMAL setting determines when
+** the xSync primitive is called and is relevant to all platforms.
+**
+** Numeric values associated with these states are OFF==1, NORMAL=2,
+** and FULL=3.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetFlags(
+  Pager *pPager,        /* The pager to set safety level for */
+  unsigned pgFlags      /* Various flags */
+){
+  unsigned level = pgFlags & PAGER_SYNCHRONOUS_MASK;
+  if( pPager->tempFile ){
+    pPager->noSync = 1;
+    pPager->fullSync = 0;
+    pPager->extraSync = 0;
+  }else{
+    pPager->noSync =  level==PAGER_SYNCHRONOUS_OFF ?1:0;
+    pPager->fullSync = level>=PAGER_SYNCHRONOUS_FULL ?1:0;
+    pPager->extraSync = level==PAGER_SYNCHRONOUS_EXTRA ?1:0;
+  }
+  if( pPager->noSync ){
+    pPager->syncFlags = 0;
+  }else if( pgFlags & PAGER_FULLFSYNC ){
+    pPager->syncFlags = SQLITE_SYNC_FULL;
+  }else{
+    pPager->syncFlags = SQLITE_SYNC_NORMAL;
+  }
+  pPager->walSyncFlags = (pPager->syncFlags<<2);
+  if( pPager->fullSync ){
+    pPager->walSyncFlags |= pPager->syncFlags;
+  }
+  if( (pgFlags & PAGER_CKPT_FULLFSYNC) && !pPager->noSync ){
+    pPager->walSyncFlags |= (SQLITE_SYNC_FULL<<2);
+  }
+  if( pgFlags & PAGER_CACHESPILL ){
+    pPager->doNotSpill &= ~SPILLFLAG_OFF;
+  }else{
+    pPager->doNotSpill |= SPILLFLAG_OFF;
+  }
+}
+
+/*
+** The following global variable is incremented whenever the library
+** attempts to open a temporary file.  This information is used for
+** testing and analysis only.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_opentemp_count = 0;
+#endif
+
+/*
+** Open a temporary file.
+**
+** Write the file descriptor into *pFile. Return SQLITE_OK on success
+** or some other error code if we fail. The OS will automatically
+** delete the temporary file when it is closed.
+**
+** The flags passed to the VFS layer xOpen() call are those specified
+** by parameter vfsFlags ORed with the following:
+**
+**     SQLITE_OPEN_READWRITE
+**     SQLITE_OPEN_CREATE
+**     SQLITE_OPEN_EXCLUSIVE
+**     SQLITE_OPEN_DELETEONCLOSE
+*/
+static int pagerOpentemp(
+  Pager *pPager,        /* The pager object */
+  sqlite3_file *pFile,  /* Write the file descriptor here */
+  int vfsFlags          /* Flags passed through to the VFS */
+){
+  int rc;               /* Return code */
+
+#ifdef SQLITE_TEST
+  sqlite3_opentemp_count++;  /* Used for testing and analysis only */
+#endif
+
+  vfsFlags |=  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
+            SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE;
+  rc = sqlite3OsOpen(pPager->pVfs, 0, pFile, vfsFlags, 0);
+  assert( rc!=SQLITE_OK || isOpen(pFile) );
+  return rc;
+}
+
+/*
+** Set the busy handler function.
+**
+** The pager invokes the busy-handler if sqlite3OsLock() returns
+** SQLITE_BUSY when trying to upgrade from no-lock to a SHARED lock,
+** or when trying to upgrade from a RESERVED lock to an EXCLUSIVE
+** lock. It does *not* invoke the busy handler when upgrading from
+** SHARED to RESERVED, or when upgrading from SHARED to EXCLUSIVE
+** (which occurs during hot-journal rollback). Summary:
+**
+**   Transition                        | Invokes xBusyHandler
+**   --------------------------------------------------------
+**   NO_LOCK       -> SHARED_LOCK      | Yes
+**   SHARED_LOCK   -> RESERVED_LOCK    | No
+**   SHARED_LOCK   -> EXCLUSIVE_LOCK   | No
+**   RESERVED_LOCK -> EXCLUSIVE_LOCK   | Yes
+**
+** If the busy-handler callback returns non-zero, the lock is
+** retried. If it returns zero, then the SQLITE_BUSY error is
+** returned to the caller of the pager API function.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetBusyHandler(
+  Pager *pPager,                       /* Pager object */
+  int (*xBusyHandler)(void *),         /* Pointer to busy-handler function */
+  void *pBusyHandlerArg                /* Argument to pass to xBusyHandler */
+){
+  void **ap;
+  pPager->xBusyHandler = xBusyHandler;
+  pPager->pBusyHandlerArg = pBusyHandlerArg;
+  ap = (void **)&pPager->xBusyHandler;
+  assert( ((int(*)(void *))(ap[0]))==xBusyHandler );
+  assert( ap[1]==pBusyHandlerArg );
+  sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_BUSYHANDLER, (void *)ap);
+}
+
+/*
+** Change the page size used by the Pager object. The new page size
+** is passed in *pPageSize.
+**
+** If the pager is in the error state when this function is called, it
+** is a no-op. The value returned is the error state error code (i.e.
+** one of SQLITE_IOERR, an SQLITE_IOERR_xxx sub-code or SQLITE_FULL).
+**
+** Otherwise, if all of the following are true:
+**
+**   * the new page size (value of *pPageSize) is valid (a power
+**     of two between 512 and SQLITE_MAX_PAGE_SIZE, inclusive), and
+**
+**   * there are no outstanding page references, and
+**
+**   * the database is either not an in-memory database or it is
+**     an in-memory database that currently consists of zero pages.
+**
+** then the pager object page size is set to *pPageSize.
+**
+** If the page size is changed, then this function uses sqlite3PagerMalloc()
+** to obtain a new Pager.pTmpSpace buffer. If this allocation attempt
+** fails, SQLITE_NOMEM is returned and the page size remains unchanged.
+** In all other cases, SQLITE_OK is returned.
+**
+** If the page size is not changed, either because one of the enumerated
+** conditions above is not true, the pager was in error state when this
+** function was called, or because the memory allocation attempt failed,
+** then *pPageSize is set to the old, retained page size before returning.
+*/
+SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager *pPager, u32 *pPageSize, int nReserve){
+  int rc = SQLITE_OK;
+
+  /* It is not possible to do a full assert_pager_state() here, as this
+  ** function may be called from within PagerOpen(), before the state
+  ** of the Pager object is internally consistent.
+  **
+  ** At one point this function returned an error if the pager was in
+  ** PAGER_ERROR state. But since PAGER_ERROR state guarantees that
+  ** there is at least one outstanding page reference, this function
+  ** is a no-op for that case anyhow.
+  */
+
+  u32 pageSize = *pPageSize;
+  assert( pageSize==0 || (pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE) );
+  if( (pPager->memDb==0 || pPager->dbSize==0)
+   && sqlite3PcacheRefCount(pPager->pPCache)==0
+   && pageSize && pageSize!=(u32)pPager->pageSize
+  ){
+    char *pNew = NULL;             /* New temp space */
+    i64 nByte = 0;
+
+    if( pPager->eState>PAGER_OPEN && isOpen(pPager->fd) ){
+      rc = sqlite3OsFileSize(pPager->fd, &nByte);
+    }
+    if( rc==SQLITE_OK ){
+      /* 8 bytes of zeroed overrun space is sufficient so that the b-tree
+      * cell header parser will never run off the end of the allocation */
+      pNew = (char *)sqlite3PageMalloc(pageSize+8);
+      if( !pNew ){
+        rc = SQLITE_NOMEM_BKPT;
+      }else{
+        memset(pNew+pageSize, 0, 8);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      pager_reset(pPager);
+      rc = sqlite3PcacheSetPageSize(pPager->pPCache, pageSize);
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3PageFree(pPager->pTmpSpace);
+      pPager->pTmpSpace = pNew;
+      pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize);
+      pPager->pageSize = pageSize;
+      pPager->lckPgno = (Pgno)(PENDING_BYTE/pageSize) + 1;
+    }else{
+      sqlite3PageFree(pNew);
+    }
+  }
+
+  *pPageSize = pPager->pageSize;
+  if( rc==SQLITE_OK ){
+    if( nReserve<0 ) nReserve = pPager->nReserve;
+    assert( nReserve>=0 && nReserve<1000 );
+    pPager->nReserve = (i16)nReserve;
+    pagerFixMaplimit(pPager);
+  }
+  return rc;
+}
+
+/*
+** Return a pointer to the "temporary page" buffer held internally
+** by the pager.  This is a buffer that is big enough to hold the
+** entire content of a database page.  This buffer is used internally
+** during rollback and will be overwritten whenever a rollback
+** occurs.  But other modules are free to use it too, as long as
+** no rollbacks are happening.
+*/
+SQLITE_PRIVATE void *sqlite3PagerTempSpace(Pager *pPager){
+  return pPager->pTmpSpace;
+}
+
+/*
+** Attempt to set the maximum database page count if mxPage is positive.
+** Make no changes if mxPage is zero or negative.  And never reduce the
+** maximum page count below the current size of the database.
+**
+** Regardless of mxPage, return the current maximum page count.
+*/
+SQLITE_PRIVATE Pgno sqlite3PagerMaxPageCount(Pager *pPager, Pgno mxPage){
+  if( mxPage>0 ){
+    pPager->mxPgno = mxPage;
+  }
+  assert( pPager->eState!=PAGER_OPEN );      /* Called only by OP_MaxPgcnt */
+  /* assert( pPager->mxPgno>=pPager->dbSize ); */
+  /* OP_MaxPgcnt ensures that the parameter passed to this function is not
+  ** less than the total number of valid pages in the database. But this
+  ** may be less than Pager.dbSize, and so the assert() above is not valid */
+  return pPager->mxPgno;
+}
+
+/*
+** The following set of routines are used to disable the simulated
+** I/O error mechanism.  These routines are used to avoid simulated
+** errors in places where we do not care about errors.
+**
+** Unless -DSQLITE_TEST=1 is used, these routines are all no-ops
+** and generate no code.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API extern int sqlite3_io_error_pending;
+SQLITE_API extern int sqlite3_io_error_hit;
+static int saved_cnt;
+void disable_simulated_io_errors(void){
+  saved_cnt = sqlite3_io_error_pending;
+  sqlite3_io_error_pending = -1;
+}
+void enable_simulated_io_errors(void){
+  sqlite3_io_error_pending = saved_cnt;
+}
+#else
+# define disable_simulated_io_errors()
+# define enable_simulated_io_errors()
+#endif
+
+/*
+** Read the first N bytes from the beginning of the file into memory
+** that pDest points to.
+**
+** If the pager was opened on a transient file (zFilename==""), or
+** opened on a file less than N bytes in size, the output buffer is
+** zeroed and SQLITE_OK returned. The rationale for this is that this
+** function is used to read database headers, and a new transient or
+** zero sized database has a header than consists entirely of zeroes.
+**
+** If any IO error apart from SQLITE_IOERR_SHORT_READ is encountered,
+** the error code is returned to the caller and the contents of the
+** output buffer undefined.
+*/
+SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
+  int rc = SQLITE_OK;
+  memset(pDest, 0, N);
+  assert( isOpen(pPager->fd) || pPager->tempFile );
+
+  /* This routine is only called by btree immediately after creating
+  ** the Pager object.  There has not been an opportunity to transition
+  ** to WAL mode yet.
+  */
+  assert( !pagerUseWal(pPager) );
+
+  if( isOpen(pPager->fd) ){
+    IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
+    rc = sqlite3OsRead(pPager->fd, pDest, N, 0);
+    if( rc==SQLITE_IOERR_SHORT_READ ){
+      rc = SQLITE_OK;
+    }
+  }
+  return rc;
+}
+
+/*
+** This function may only be called when a read-transaction is open on
+** the pager. It returns the total number of pages in the database.
+**
+** However, if the file is between 1 and <page-size> bytes in size, then
+** this is considered a 1 page file.
+*/
+SQLITE_PRIVATE void sqlite3PagerPagecount(Pager *pPager, int *pnPage){
+  assert( pPager->eState>=PAGER_READER );
+  assert( pPager->eState!=PAGER_WRITER_FINISHED );
+  *pnPage = (int)pPager->dbSize;
+}
+
+
+/*
+** Try to obtain a lock of type locktype on the database file. If
+** a similar or greater lock is already held, this function is a no-op
+** (returning SQLITE_OK immediately).
+**
+** Otherwise, attempt to obtain the lock using sqlite3OsLock(). Invoke
+** the busy callback if the lock is currently not available. Repeat
+** until the busy callback returns false or until the attempt to
+** obtain the lock succeeds.
+**
+** Return SQLITE_OK on success and an error code if we cannot obtain
+** the lock. If the lock is obtained successfully, set the Pager.state
+** variable to locktype before returning.
+*/
+static int pager_wait_on_lock(Pager *pPager, int locktype){
+  int rc;                              /* Return code */
+
+  /* Check that this is either a no-op (because the requested lock is
+  ** already held), or one of the transitions that the busy-handler
+  ** may be invoked during, according to the comment above
+  ** sqlite3PagerSetBusyhandler().
+  */
+  assert( (pPager->eLock>=locktype)
+       || (pPager->eLock==NO_LOCK && locktype==SHARED_LOCK)
+       || (pPager->eLock==RESERVED_LOCK && locktype==EXCLUSIVE_LOCK)
+  );
+
+  do {
+    rc = pagerLockDb(pPager, locktype);
+  }while( rc==SQLITE_BUSY && pPager->xBusyHandler(pPager->pBusyHandlerArg) );
+  return rc;
+}
+
+/*
+** Function assertTruncateConstraint(pPager) checks that one of the
+** following is true for all dirty pages currently in the page-cache:
+**
+**   a) The page number is less than or equal to the size of the
+**      current database image, in pages, OR
+**
+**   b) if the page content were written at this time, it would not
+**      be necessary to write the current content out to the sub-journal.
+**
+** If the condition asserted by this function were not true, and the
+** dirty page were to be discarded from the cache via the pagerStress()
+** routine, pagerStress() would not write the current page content to
+** the database file. If a savepoint transaction were rolled back after
+** this happened, the correct behavior would be to restore the current
+** content of the page. However, since this content is not present in either
+** the database file or the portion of the rollback journal and
+** sub-journal rolled back the content could not be restored and the
+** database image would become corrupt. It is therefore fortunate that
+** this circumstance cannot arise.
+*/
+#if defined(SQLITE_DEBUG)
+static void assertTruncateConstraintCb(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  assert( pPg->flags&PGHDR_DIRTY );
+  if( pPg->pgno>pPager->dbSize ){      /* if (a) is false */
+    Pgno pgno = pPg->pgno;
+    int i;
+    for(i=0; i<pPg->pPager->nSavepoint; i++){
+      PagerSavepoint *p = &pPager->aSavepoint[i];
+      assert( p->nOrig<pgno || sqlite3BitvecTestNotNull(p->pInSavepoint,pgno) );
+    }
+  }
+}
+static void assertTruncateConstraint(Pager *pPager){
+  sqlite3PcacheIterateDirty(pPager->pPCache, assertTruncateConstraintCb);
+}
+#else
+# define assertTruncateConstraint(pPager)
+#endif
+
+/*
+** Truncate the in-memory database file image to nPage pages. This
+** function does not actually modify the database file on disk. It
+** just sets the internal state of the pager object so that the
+** truncation will be done when the current transaction is committed.
+**
+** This function is only called right before committing a transaction.
+** Once this function has been called, the transaction must either be
+** rolled back or committed. It is not safe to call this function and
+** then continue writing to the database.
+*/
+SQLITE_PRIVATE void sqlite3PagerTruncateImage(Pager *pPager, Pgno nPage){
+  assert( pPager->dbSize>=nPage || CORRUPT_DB );
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD );
+  pPager->dbSize = nPage;
+
+  /* At one point the code here called assertTruncateConstraint() to
+  ** ensure that all pages being truncated away by this operation are,
+  ** if one or more savepoints are open, present in the savepoint
+  ** journal so that they can be restored if the savepoint is rolled
+  ** back. This is no longer necessary as this function is now only
+  ** called right before committing a transaction. So although the
+  ** Pager object may still have open savepoints (Pager.nSavepoint!=0),
+  ** they cannot be rolled back. So the assertTruncateConstraint() call
+  ** is no longer correct. */
+}
+
+
+/*
+** This function is called before attempting a hot-journal rollback. It
+** syncs the journal file to disk, then sets pPager->journalHdr to the
+** size of the journal file so that the pager_playback() routine knows
+** that the entire journal file has been synced.
+**
+** Syncing a hot-journal to disk before attempting to roll it back ensures
+** that if a power-failure occurs during the rollback, the process that
+** attempts rollback following system recovery sees the same journal
+** content as this process.
+**
+** If everything goes as planned, SQLITE_OK is returned. Otherwise,
+** an SQLite error code.
+*/
+static int pagerSyncHotJournal(Pager *pPager){
+  int rc = SQLITE_OK;
+  if( !pPager->noSync ){
+    rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_NORMAL);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3OsFileSize(pPager->jfd, &pPager->journalHdr);
+  }
+  return rc;
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/*
+** Obtain a reference to a memory mapped page object for page number pgno.
+** The new object will use the pointer pData, obtained from xFetch().
+** If successful, set *ppPage to point to the new page reference
+** and return SQLITE_OK. Otherwise, return an SQLite error code and set
+** *ppPage to zero.
+**
+** Page references obtained by calling this function should be released
+** by calling pagerReleaseMapPage().
+*/
+static int pagerAcquireMapPage(
+  Pager *pPager,                  /* Pager object */
+  Pgno pgno,                      /* Page number */
+  void *pData,                    /* xFetch()'d data for this page */
+  PgHdr **ppPage                  /* OUT: Acquired page object */
+){
+  PgHdr *p;                       /* Memory mapped page to return */
+
+  if( pPager->pMmapFreelist ){
+    *ppPage = p = pPager->pMmapFreelist;
+    pPager->pMmapFreelist = p->pDirty;
+    p->pDirty = 0;
+    assert( pPager->nExtra>=8 );
+    memset(p->pExtra, 0, 8);
+  }else{
+    *ppPage = p = (PgHdr *)sqlite3MallocZero(sizeof(PgHdr) + pPager->nExtra);
+    if( p==0 ){
+      sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1) * pPager->pageSize, pData);
+      return SQLITE_NOMEM_BKPT;
+    }
+    p->pExtra = (void *)&p[1];
+    assert( EIGHT_BYTE_ALIGNMENT( p->pExtra ) );
+    p->flags = PGHDR_MMAP;
+    p->nRef = 1;
+    p->pPager = pPager;
+  }
+
+  assert( p->pExtra==(void *)&p[1] );
+  assert( p->pPage==0 );
+  assert( p->flags==PGHDR_MMAP );
+  assert( p->pPager==pPager );
+  assert( p->nRef==1 );
+
+  p->pgno = pgno;
+  p->pData = pData;
+  pPager->nMmapOut++;
+
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Release a reference to page pPg. pPg must have been returned by an
+** earlier call to pagerAcquireMapPage().
+*/
+static void pagerReleaseMapPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  pPager->nMmapOut--;
+  pPg->pDirty = pPager->pMmapFreelist;
+  pPager->pMmapFreelist = pPg;
+
+  assert( pPager->fd->pMethods->iVersion>=3 );
+  sqlite3OsUnfetch(pPager->fd, (i64)(pPg->pgno-1)*pPager->pageSize, pPg->pData);
+}
+
+/*
+** Free all PgHdr objects stored in the Pager.pMmapFreelist list.
+*/
+static void pagerFreeMapHdrs(Pager *pPager){
+  PgHdr *p;
+  PgHdr *pNext;
+  for(p=pPager->pMmapFreelist; p; p=pNext){
+    pNext = p->pDirty;
+    sqlite3_free(p);
+  }
+}
+
+/* Verify that the database file has not be deleted or renamed out from
+** under the pager.  Return SQLITE_OK if the database is still where it ought
+** to be on disk.  Return non-zero (SQLITE_READONLY_DBMOVED or some other error
+** code from sqlite3OsAccess()) if the database has gone missing.
+*/
+static int databaseIsUnmoved(Pager *pPager){
+  int bHasMoved = 0;
+  int rc;
+
+  if( pPager->tempFile ) return SQLITE_OK;
+  if( pPager->dbSize==0 ) return SQLITE_OK;
+  assert( pPager->zFilename && pPager->zFilename[0] );
+  rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_HAS_MOVED, &bHasMoved);
+  if( rc==SQLITE_NOTFOUND ){
+    /* If the HAS_MOVED file-control is unimplemented, assume that the file
+    ** has not been moved.  That is the historical behavior of SQLite: prior to
+    ** version 3.8.3, it never checked */
+    rc = SQLITE_OK;
+  }else if( rc==SQLITE_OK && bHasMoved ){
+    rc = SQLITE_READONLY_DBMOVED;
+  }
+  return rc;
+}
+
+
+/*
+** Shutdown the page cache.  Free all memory and close all files.
+**
+** If a transaction was in progress when this routine is called, that
+** transaction is rolled back.  All outstanding pages are invalidated
+** and their memory is freed.  Any attempt to use a page associated
+** with this page cache after this function returns will likely
+** result in a coredump.
+**
+** This function always succeeds. If a transaction is active an attempt
+** is made to roll it back. If an error occurs during the rollback
+** a hot journal may be left in the filesystem but no error is returned
+** to the caller.
+*/
+SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager, sqlite3 *db){
+  u8 *pTmp = (u8*)pPager->pTmpSpace;
+  assert( db || pagerUseWal(pPager)==0 );
+  assert( assert_pager_state(pPager) );
+  disable_simulated_io_errors();
+  sqlite3BeginBenignMalloc();
+  pagerFreeMapHdrs(pPager);
+  /* pPager->errCode = 0; */
+  pPager->exclusiveMode = 0;
+#ifndef SQLITE_OMIT_WAL
+  {
+    u8 *a = 0;
+    assert( db || pPager->pWal==0 );
+    if( db && 0==(db->flags & SQLITE_NoCkptOnClose)
+     && SQLITE_OK==databaseIsUnmoved(pPager)
+    ){
+      a = pTmp;
+    }
+    sqlite3WalClose(pPager->pWal, db, pPager->walSyncFlags, pPager->pageSize,a);
+    pPager->pWal = 0;
+  }
+#endif
+  pager_reset(pPager);
+  if( MEMDB ){
+    pager_unlock(pPager);
+  }else{
+    /* If it is open, sync the journal file before calling UnlockAndRollback.
+    ** If this is not done, then an unsynced portion of the open journal
+    ** file may be played back into the database. If a power failure occurs
+    ** while this is happening, the database could become corrupt.
+    **
+    ** If an error occurs while trying to sync the journal, shift the pager
+    ** into the ERROR state. This causes UnlockAndRollback to unlock the
+    ** database and close the journal file without attempting to roll it
+    ** back or finalize it. The next database user will have to do hot-journal
+    ** rollback before accessing the database file.
+    */
+    if( isOpen(pPager->jfd) ){
+      pager_error(pPager, pagerSyncHotJournal(pPager));
+    }
+    pagerUnlockAndRollback(pPager);
+  }
+  sqlite3EndBenignMalloc();
+  enable_simulated_io_errors();
+  PAGERTRACE(("CLOSE %d\n", PAGERID(pPager)));
+  IOTRACE(("CLOSE %p\n", pPager))
+  sqlite3OsClose(pPager->jfd);
+  sqlite3OsClose(pPager->fd);
+  sqlite3PageFree(pTmp);
+  sqlite3PcacheClose(pPager->pPCache);
+  assert( !pPager->aSavepoint && !pPager->pInJournal );
+  assert( !isOpen(pPager->jfd) && !isOpen(pPager->sjfd) );
+
+  sqlite3_free(pPager);
+  return SQLITE_OK;
+}
+
+#if !defined(NDEBUG) || defined(SQLITE_TEST)
+/*
+** Return the page number for page pPg.
+*/
+SQLITE_PRIVATE Pgno sqlite3PagerPagenumber(DbPage *pPg){
+  return pPg->pgno;
+}
+#endif
+
+/*
+** Increment the reference count for page pPg.
+*/
+SQLITE_PRIVATE void sqlite3PagerRef(DbPage *pPg){
+  sqlite3PcacheRef(pPg);
+}
+
+/*
+** Sync the journal. In other words, make sure all the pages that have
+** been written to the journal have actually reached the surface of the
+** disk and can be restored in the event of a hot-journal rollback.
+**
+** If the Pager.noSync flag is set, then this function is a no-op.
+** Otherwise, the actions required depend on the journal-mode and the
+** device characteristics of the file-system, as follows:
+**
+**   * If the journal file is an in-memory journal file, no action need
+**     be taken.
+**
+**   * Otherwise, if the device does not support the SAFE_APPEND property,
+**     then the nRec field of the most recently written journal header
+**     is updated to contain the number of journal records that have
+**     been written following it. If the pager is operating in full-sync
+**     mode, then the journal file is synced before this field is updated.
+**
+**   * If the device does not support the SEQUENTIAL property, then
+**     journal file is synced.
+**
+** Or, in pseudo-code:
+**
+**   if( NOT <in-memory journal> ){
+**     if( NOT SAFE_APPEND ){
+**       if( <full-sync mode> ) xSync(<journal file>);
+**       <update nRec field>
+**     }
+**     if( NOT SEQUENTIAL ) xSync(<journal file>);
+**   }
+**
+** If successful, this routine clears the PGHDR_NEED_SYNC flag of every
+** page currently held in memory before returning SQLITE_OK. If an IO
+** error is encountered, then the IO error code is returned to the caller.
+*/
+static int syncJournal(Pager *pPager, int newHdr){
+  int rc;                         /* Return code */
+
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+  assert( !pagerUseWal(pPager) );
+
+  rc = sqlite3PagerExclusiveLock(pPager);
+  if( rc!=SQLITE_OK ) return rc;
+
+  if( !pPager->noSync ){
+    assert( !pPager->tempFile );
+    if( isOpen(pPager->jfd) && pPager->journalMode!=PAGER_JOURNALMODE_MEMORY ){
+      const int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
+      assert( isOpen(pPager->jfd) );
+
+      if( 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
+        /* This block deals with an obscure problem. If the last connection
+        ** that wrote to this database was operating in persistent-journal
+        ** mode, then the journal file may at this point actually be larger
+        ** than Pager.journalOff bytes. If the next thing in the journal
+        ** file happens to be a journal-header (written as part of the
+        ** previous connection's transaction), and a crash or power-failure
+        ** occurs after nRec is updated but before this connection writes
+        ** anything else to the journal file (or commits/rolls back its
+        ** transaction), then SQLite may become confused when doing the
+        ** hot-journal rollback following recovery. It may roll back all
+        ** of this connections data, then proceed to rolling back the old,
+        ** out-of-date data that follows it. Database corruption.
+        **
+        ** To work around this, if the journal file does appear to contain
+        ** a valid header following Pager.journalOff, then write a 0x00
+        ** byte to the start of it to prevent it from being recognized.
+        **
+        ** Variable iNextHdrOffset is set to the offset at which this
+        ** problematic header will occur, if it exists. aMagic is used
+        ** as a temporary buffer to inspect the first couple of bytes of
+        ** the potential journal header.
+        */
+        i64 iNextHdrOffset;
+        u8 aMagic[8];
+        u8 zHeader[sizeof(aJournalMagic)+4];
+
+        memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
+        put32bits(&zHeader[sizeof(aJournalMagic)], pPager->nRec);
+
+        iNextHdrOffset = journalHdrOffset(pPager);
+        rc = sqlite3OsRead(pPager->jfd, aMagic, 8, iNextHdrOffset);
+        if( rc==SQLITE_OK && 0==memcmp(aMagic, aJournalMagic, 8) ){
+          static const u8 zerobyte = 0;
+          rc = sqlite3OsWrite(pPager->jfd, &zerobyte, 1, iNextHdrOffset);
+        }
+        if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
+          return rc;
+        }
+
+        /* Write the nRec value into the journal file header. If in
+        ** full-synchronous mode, sync the journal first. This ensures that
+        ** all data has really hit the disk before nRec is updated to mark
+        ** it as a candidate for rollback.
+        **
+        ** This is not required if the persistent media supports the
+        ** SAFE_APPEND property. Because in this case it is not possible
+        ** for garbage data to be appended to the file, the nRec field
+        ** is populated with 0xFFFFFFFF when the journal header is written
+        ** and never needs to be updated.
+        */
+        if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
+          PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
+          IOTRACE(("JSYNC %p\n", pPager))
+          rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags);
+          if( rc!=SQLITE_OK ) return rc;
+        }
+        IOTRACE(("JHDR %p %lld\n", pPager, pPager->journalHdr));
+        rc = sqlite3OsWrite(
+            pPager->jfd, zHeader, sizeof(zHeader), pPager->journalHdr
+        );
+        if( rc!=SQLITE_OK ) return rc;
+      }
+      if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
+        PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
+        IOTRACE(("JSYNC %p\n", pPager))
+        rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags|
+          (pPager->syncFlags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
+        );
+        if( rc!=SQLITE_OK ) return rc;
+      }
+
+      pPager->journalHdr = pPager->journalOff;
+      if( newHdr && 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
+        pPager->nRec = 0;
+        rc = writeJournalHdr(pPager);
+        if( rc!=SQLITE_OK ) return rc;
+      }
+    }else{
+      pPager->journalHdr = pPager->journalOff;
+    }
+  }
+
+  /* Unless the pager is in noSync mode, the journal file was just
+  ** successfully synced. Either way, clear the PGHDR_NEED_SYNC flag on
+  ** all pages.
+  */
+  sqlite3PcacheClearSyncFlags(pPager->pPCache);
+  pPager->eState = PAGER_WRITER_DBMOD;
+  assert( assert_pager_state(pPager) );
+  return SQLITE_OK;
+}
+
+/*
+** The argument is the first in a linked list of dirty pages connected
+** by the PgHdr.pDirty pointer. This function writes each one of the
+** in-memory pages in the list to the database file. The argument may
+** be NULL, representing an empty list. In this case this function is
+** a no-op.
+**
+** The pager must hold at least a RESERVED lock when this function
+** is called. Before writing anything to the database file, this lock
+** is upgraded to an EXCLUSIVE lock. If the lock cannot be obtained,
+** SQLITE_BUSY is returned and no data is written to the database file.
+**
+** If the pager is a temp-file pager and the actual file-system file
+** is not yet open, it is created and opened before any data is
+** written out.
+**
+** Once the lock has been upgraded and, if necessary, the file opened,
+** the pages are written out to the database file in list order. Writing
+** a page is skipped if it meets either of the following criteria:
+**
+**   * The page number is greater than Pager.dbSize, or
+**   * The PGHDR_DONT_WRITE flag is set on the page.
+**
+** If writing out a page causes the database file to grow, Pager.dbFileSize
+** is updated accordingly. If page 1 is written out, then the value cached
+** in Pager.dbFileVers[] is updated to match the new value stored in
+** the database file.
+**
+** If everything is successful, SQLITE_OK is returned. If an IO error
+** occurs, an IO error code is returned. Or, if the EXCLUSIVE lock cannot
+** be obtained, SQLITE_BUSY is returned.
+*/
+static int pager_write_pagelist(Pager *pPager, PgHdr *pList){
+  int rc = SQLITE_OK;                  /* Return code */
+
+  /* This function is only called for rollback pagers in WRITER_DBMOD state. */
+  assert( !pagerUseWal(pPager) );
+  assert( pPager->tempFile || pPager->eState==PAGER_WRITER_DBMOD );
+  assert( pPager->eLock==EXCLUSIVE_LOCK );
+  assert( isOpen(pPager->fd) || pList->pDirty==0 );
+
+  /* If the file is a temp-file has not yet been opened, open it now. It
+  ** is not possible for rc to be other than SQLITE_OK if this branch
+  ** is taken, as pager_wait_on_lock() is a no-op for temp-files.
+  */
+  if( !isOpen(pPager->fd) ){
+    assert( pPager->tempFile && rc==SQLITE_OK );
+    rc = pagerOpentemp(pPager, pPager->fd, pPager->vfsFlags);
+  }
+
+  /* Before the first write, give the VFS a hint of what the final
+  ** file size will be.
+  */
+  assert( rc!=SQLITE_OK || isOpen(pPager->fd) );
+  if( rc==SQLITE_OK
+   && pPager->dbHintSize<pPager->dbSize
+   && (pList->pDirty || pList->pgno>pPager->dbHintSize)
+  ){
+    sqlite3_int64 szFile = pPager->pageSize * (sqlite3_int64)pPager->dbSize;
+    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);
+    pPager->dbHintSize = pPager->dbSize;
+  }
+
+  while( rc==SQLITE_OK && pList ){
+    Pgno pgno = pList->pgno;
+
+    /* If there are dirty pages in the page cache with page numbers greater
+    ** than Pager.dbSize, this means sqlite3PagerTruncateImage() was called to
+    ** make the file smaller (presumably by auto-vacuum code). Do not write
+    ** any such pages to the file.
+    **
+    ** Also, do not write out any page that has the PGHDR_DONT_WRITE flag
+    ** set (set by sqlite3PagerDontWrite()).
+    */
+    if( pgno<=pPager->dbSize && 0==(pList->flags&PGHDR_DONT_WRITE) ){
+      i64 offset = (pgno-1)*(i64)pPager->pageSize;   /* Offset to write */
+      char *pData;                                   /* Data to write */
+
+      assert( (pList->flags&PGHDR_NEED_SYNC)==0 );
+      if( pList->pgno==1 ) pager_write_changecounter(pList);
+
+      pData = pList->pData;
+
+      /* Write out the page data. */
+      rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize, offset);
+
+      /* If page 1 was just written, update Pager.dbFileVers to match
+      ** the value now stored in the database file. If writing this
+      ** page caused the database file to grow, update dbFileSize.
+      */
+      if( pgno==1 ){
+        memcpy(&pPager->dbFileVers, &pData[24], sizeof(pPager->dbFileVers));
+      }
+      if( pgno>pPager->dbFileSize ){
+        pPager->dbFileSize = pgno;
+      }
+      pPager->aStat[PAGER_STAT_WRITE]++;
+
+      /* Update any backup objects copying the contents of this pager. */
+      sqlite3BackupUpdate(pPager->pBackup, pgno, (u8*)pList->pData);
+
+      PAGERTRACE(("STORE %d page %d hash(%08x)\n",
+                   PAGERID(pPager), pgno, pager_pagehash(pList)));
+      IOTRACE(("PGOUT %p %d\n", pPager, pgno));
+      PAGER_INCR(sqlite3_pager_writedb_count);
+    }else{
+      PAGERTRACE(("NOSTORE %d page %d\n", PAGERID(pPager), pgno));
+    }
+    pager_set_pagehash(pList);
+    pList = pList->pDirty;
+  }
+
+  return rc;
+}
+
+/*
+** Ensure that the sub-journal file is open. If it is already open, this
+** function is a no-op.
+**
+** SQLITE_OK is returned if everything goes according to plan. An
+** SQLITE_IOERR_XXX error code is returned if a call to sqlite3OsOpen()
+** fails.
+*/
+static int openSubJournal(Pager *pPager){
+  int rc = SQLITE_OK;
+  if( !isOpen(pPager->sjfd) ){
+    const int flags =  SQLITE_OPEN_SUBJOURNAL | SQLITE_OPEN_READWRITE
+      | SQLITE_OPEN_CREATE | SQLITE_OPEN_EXCLUSIVE
+      | SQLITE_OPEN_DELETEONCLOSE;
+    int nStmtSpill = sqlite3Config.nStmtSpill;
+    if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY || pPager->subjInMemory ){
+      nStmtSpill = -1;
+    }
+    rc = sqlite3JournalOpen(pPager->pVfs, 0, pPager->sjfd, flags, nStmtSpill);
+  }
+  return rc;
+}
+
+/*
+** Append a record of the current state of page pPg to the sub-journal.
+**
+** If successful, set the bit corresponding to pPg->pgno in the bitvecs
+** for all open savepoints before returning.
+**
+** This function returns SQLITE_OK if everything is successful, an IO
+** error code if the attempt to write to the sub-journal fails, or
+** SQLITE_NOMEM if a malloc fails while setting a bit in a savepoint
+** bitvec.
+*/
+static int subjournalPage(PgHdr *pPg){
+  int rc = SQLITE_OK;
+  Pager *pPager = pPg->pPager;
+  if( pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
+
+    /* Open the sub-journal, if it has not already been opened */
+    assert( pPager->useJournal );
+    assert( isOpen(pPager->jfd) || pagerUseWal(pPager) );
+    assert( isOpen(pPager->sjfd) || pPager->nSubRec==0 );
+    assert( pagerUseWal(pPager)
+         || pageInJournal(pPager, pPg)
+         || pPg->pgno>pPager->dbOrigSize
+    );
+    rc = openSubJournal(pPager);
+
+    /* If the sub-journal was opened successfully (or was already open),
+    ** write the journal record into the file.  */
+    if( rc==SQLITE_OK ){
+      void *pData = pPg->pData;
+      i64 offset = (i64)pPager->nSubRec*(4+pPager->pageSize);
+      char *pData2;
+      pData2 = pData;
+      PAGERTRACE(("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno));
+      rc = write32bits(pPager->sjfd, offset, pPg->pgno);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
+      }
+    }
+  }
+  if( rc==SQLITE_OK ){
+    pPager->nSubRec++;
+    assert( pPager->nSavepoint>0 );
+    rc = addToSavepointBitvecs(pPager, pPg->pgno);
+  }
+  return rc;
+}
+static int subjournalPageIfRequired(PgHdr *pPg){
+  if( subjRequiresPage(pPg) ){
+    return subjournalPage(pPg);
+  }else{
+    return SQLITE_OK;
+  }
+}
+
+/*
+** This function is called by the pcache layer when it has reached some
+** soft memory limit. The first argument is a pointer to a Pager object
+** (cast as a void*). The pager is always 'purgeable' (not an in-memory
+** database). The second argument is a reference to a page that is
+** currently dirty but has no outstanding references. The page
+** is always associated with the Pager object passed as the first
+** argument.
+**
+** The job of this function is to make pPg clean by writing its contents
+** out to the database file, if possible. This may involve syncing the
+** journal file.
+**
+** If successful, sqlite3PcacheMakeClean() is called on the page and
+** SQLITE_OK returned. If an IO error occurs while trying to make the
+** page clean, the IO error code is returned. If the page cannot be
+** made clean for some other reason, but no error occurs, then SQLITE_OK
+** is returned by sqlite3PcacheMakeClean() is not called.
+*/
+static int pagerStress(void *p, PgHdr *pPg){
+  Pager *pPager = (Pager *)p;
+  int rc = SQLITE_OK;
+
+  assert( pPg->pPager==pPager );
+  assert( pPg->flags&PGHDR_DIRTY );
+
+  /* The doNotSpill NOSYNC bit is set during times when doing a sync of
+  ** journal (and adding a new header) is not allowed.  This occurs
+  ** during calls to sqlite3PagerWrite() while trying to journal multiple
+  ** pages belonging to the same sector.
+  **
+  ** The doNotSpill ROLLBACK and OFF bits inhibits all cache spilling
+  ** regardless of whether or not a sync is required.  This is set during
+  ** a rollback or by user request, respectively.
+  **
+  ** Spilling is also prohibited when in an error state since that could
+  ** lead to database corruption.   In the current implementation it
+  ** is impossible for sqlite3PcacheFetch() to be called with createFlag==3
+  ** while in the error state, hence it is impossible for this routine to
+  ** be called in the error state.  Nevertheless, we include a NEVER()
+  ** test for the error state as a safeguard against future changes.
+  */
+  if( NEVER(pPager->errCode) ) return SQLITE_OK;
+  testcase( pPager->doNotSpill & SPILLFLAG_ROLLBACK );
+  testcase( pPager->doNotSpill & SPILLFLAG_OFF );
+  testcase( pPager->doNotSpill & SPILLFLAG_NOSYNC );
+  if( pPager->doNotSpill
+   && ((pPager->doNotSpill & (SPILLFLAG_ROLLBACK|SPILLFLAG_OFF))!=0
+      || (pPg->flags & PGHDR_NEED_SYNC)!=0)
+  ){
+    return SQLITE_OK;
+  }
+
+  pPager->aStat[PAGER_STAT_SPILL]++;
+  pPg->pDirty = 0;
+  if( pagerUseWal(pPager) ){
+    /* Write a single frame for this page to the log. */
+    rc = subjournalPageIfRequired(pPg);
+    if( rc==SQLITE_OK ){
+      rc = pagerWalFrames(pPager, pPg, 0, 0);
+    }
+  }else{
+
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+    if( pPager->tempFile==0 ){
+      rc = sqlite3JournalCreate(pPager->jfd);
+      if( rc!=SQLITE_OK ) return pager_error(pPager, rc);
+    }
+#endif
+
+    /* Sync the journal file if required. */
+    if( pPg->flags&PGHDR_NEED_SYNC
+     || pPager->eState==PAGER_WRITER_CACHEMOD
+    ){
+      rc = syncJournal(pPager, 1);
+    }
+
+    /* Write the contents of the page out to the database file. */
+    if( rc==SQLITE_OK ){
+      assert( (pPg->flags&PGHDR_NEED_SYNC)==0 );
+      rc = pager_write_pagelist(pPager, pPg);
+    }
+  }
+
+  /* Mark the page as clean. */
+  if( rc==SQLITE_OK ){
+    PAGERTRACE(("STRESS %d page %d\n", PAGERID(pPager), pPg->pgno));
+    sqlite3PcacheMakeClean(pPg);
+  }
+
+  return pager_error(pPager, rc);
+}
+
+/*
+** Flush all unreferenced dirty pages to disk.
+*/
+SQLITE_PRIVATE int sqlite3PagerFlush(Pager *pPager){
+  int rc = pPager->errCode;
+  if( !MEMDB ){
+    PgHdr *pList = sqlite3PcacheDirtyList(pPager->pPCache);
+    assert( assert_pager_state(pPager) );
+    while( rc==SQLITE_OK && pList ){
+      PgHdr *pNext = pList->pDirty;
+      if( pList->nRef==0 ){
+        rc = pagerStress((void*)pPager, pList);
+      }
+      pList = pNext;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Allocate and initialize a new Pager object and put a pointer to it
+** in *ppPager. The pager should eventually be freed by passing it
+** to sqlite3PagerClose().
+**
+** The zFilename argument is the path to the database file to open.
+** If zFilename is NULL then a randomly-named temporary file is created
+** and used as the file to be cached. Temporary files are be deleted
+** automatically when they are closed. If zFilename is ":memory:" then
+** all information is held in cache. It is never written to disk.
+** This can be used to implement an in-memory database.
+**
+** The nExtra parameter specifies the number of bytes of space allocated
+** along with each page reference. This space is available to the user
+** via the sqlite3PagerGetExtra() API.  When a new page is allocated, the
+** first 8 bytes of this space are zeroed but the remainder is uninitialized.
+** (The extra space is used by btree as the MemPage object.)
+**
+** The flags argument is used to specify properties that affect the
+** operation of the pager. It should be passed some bitwise combination
+** of the PAGER_* flags.
+**
+** The vfsFlags parameter is a bitmask to pass to the flags parameter
+** of the xOpen() method of the supplied VFS when opening files.
+**
+** If the pager object is allocated and the specified file opened
+** successfully, SQLITE_OK is returned and *ppPager set to point to
+** the new pager object. If an error occurs, *ppPager is set to NULL
+** and error code returned. This function may return SQLITE_NOMEM
+** (sqlite3Malloc() is used to allocate memory), SQLITE_CANTOPEN or
+** various SQLITE_IO_XXX errors.
+*/
+SQLITE_PRIVATE int sqlite3PagerOpen(
+  sqlite3_vfs *pVfs,       /* The virtual file system to use */
+  Pager **ppPager,         /* OUT: Return the Pager structure here */
+  const char *zFilename,   /* Name of the database file to open */
+  int nExtra,              /* Extra bytes append to each in-memory page */
+  int flags,               /* flags controlling this file */
+  int vfsFlags,            /* flags passed through to sqlite3_vfs.xOpen() */
+  void (*xReinit)(DbPage*) /* Function to reinitialize pages */
+){
+  u8 *pPtr;
+  Pager *pPager = 0;       /* Pager object to allocate and return */
+  int rc = SQLITE_OK;      /* Return code */
+  int tempFile = 0;        /* True for temp files (incl. in-memory files) */
+  int memDb = 0;           /* True if this is an in-memory file */
+  int memJM = 0;           /* Memory journal mode */
+  int readOnly = 0;        /* True if this is a read-only file */
+  int journalFileSize;     /* Bytes to allocate for each journal fd */
+  char *zPathname = 0;     /* Full path to database file */
+  int nPathname = 0;       /* Number of bytes in zPathname */
+  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0; /* False to omit journal */
+  int pcacheSize = sqlite3PcacheSize();       /* Bytes to allocate for PCache */
+  u32 szPageDflt = SQLITE_DEFAULT_PAGE_SIZE;  /* Default page size */
+  const char *zUri = 0;    /* URI args to copy */
+  int nUriByte = 1;        /* Number of bytes of URI args at *zUri */
+
+  /* Figure out how much space is required for each journal file-handle
+  ** (there are two of them, the main journal and the sub-journal).  */
+  journalFileSize = ROUND8(sqlite3JournalSize(pVfs));
+
+  /* Set the output variable to NULL in case an error occurs. */
+  *ppPager = 0;
+
+#ifndef SQLITE_OMIT_MEMORYDB
+  if( flags & PAGER_MEMORY ){
+    memDb = 1;
+    if( zFilename && zFilename[0] ){
+      zPathname = sqlite3DbStrDup(0, zFilename);
+      if( zPathname==0  ) return SQLITE_NOMEM_BKPT;
+      nPathname = sqlite3Strlen30(zPathname);
+      zFilename = 0;
+    }
+  }
+#endif
+
+  /* Compute and store the full pathname in an allocated buffer pointed
+  ** to by zPathname, length nPathname. Or, if this is a temporary file,
+  ** leave both nPathname and zPathname set to 0.
+  */
+  if( zFilename && zFilename[0] ){
+    const char *z;
+    nPathname = pVfs->mxPathname+1;
+    zPathname = sqlite3DbMallocRaw(0, nPathname*2);
+    if( zPathname==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    zPathname[0] = 0; /* Make sure initialized even if FullPathname() fails */
+    rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_OK_SYMLINK ){
+        if( vfsFlags & SQLITE_OPEN_NOFOLLOW ){
+          rc = SQLITE_CANTOPEN_SYMLINK;
+        }else{
+          rc = SQLITE_OK;
+        }
+      }
+    }
+    nPathname = sqlite3Strlen30(zPathname);
+    z = zUri = &zFilename[sqlite3Strlen30(zFilename)+1];
+    while( *z ){
+      z += strlen(z)+1;
+      z += strlen(z)+1;
+    }
+    nUriByte = (int)(&z[1] - zUri);
+    assert( nUriByte>=1 );
+    if( rc==SQLITE_OK && nPathname+8>pVfs->mxPathname ){
+      /* This branch is taken when the journal path required by
+      ** the database being opened will be more than pVfs->mxPathname
+      ** bytes in length. This means the database cannot be opened,
+      ** as it will not be possible to open the journal file or even
+      ** check for a hot-journal before reading.
+      */
+      rc = SQLITE_CANTOPEN_BKPT;
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3DbFree(0, zPathname);
+      return rc;
+    }
+  }
+
+  /* Allocate memory for the Pager structure, PCache object, the
+  ** three file descriptors, the database file name and the journal
+  ** file name. The layout in memory is as follows:
+  **
+  **     Pager object                    (sizeof(Pager) bytes)
+  **     PCache object                   (sqlite3PcacheSize() bytes)
+  **     Database file handle            (pVfs->szOsFile bytes)
+  **     Sub-journal file handle         (journalFileSize bytes)
+  **     Main journal file handle        (journalFileSize bytes)
+  **     Ptr back to the Pager           (sizeof(Pager*) bytes)
+  **     \0\0\0\0 database prefix        (4 bytes)
+  **     Database file name              (nPathname+1 bytes)
+  **     URI query parameters            (nUriByte bytes)
+  **     Journal filename                (nPathname+8+1 bytes)
+  **     WAL filename                    (nPathname+4+1 bytes)
+  **     \0\0\0 terminator               (3 bytes)
+  **
+  ** Some 3rd-party software, over which we have no control, depends on
+  ** the specific order of the filenames and the \0 separators between them
+  ** so that it can (for example) find the database filename given the WAL
+  ** filename without using the sqlite3_filename_database() API.  This is a
+  ** misuse of SQLite and a bug in the 3rd-party software, but the 3rd-party
+  ** software is in widespread use, so we try to avoid changing the filename
+  ** order and formatting if possible.  In particular, the details of the
+  ** filename format expected by 3rd-party software should be as follows:
+  **
+  **   - Main Database Path
+  **   - \0
+  **   - Multiple URI components consisting of:
+  **     - Key
+  **     - \0
+  **     - Value
+  **     - \0
+  **   - \0
+  **   - Journal Path
+  **   - \0
+  **   - WAL Path (zWALName)
+  **   - \0
+  **
+  ** The sqlite3_create_filename() interface and the databaseFilename() utility
+  ** that is used by sqlite3_filename_database() and kin also depend on the
+  ** specific formatting and order of the various filenames, so if the format
+  ** changes here, be sure to change it there as well.
+  */
+  assert( SQLITE_PTRSIZE==sizeof(Pager*) );
+  pPtr = (u8 *)sqlite3MallocZero(
+    ROUND8(sizeof(*pPager)) +            /* Pager structure */
+    ROUND8(pcacheSize) +                 /* PCache object */
+    ROUND8(pVfs->szOsFile) +             /* The main db file */
+    journalFileSize * 2 +                /* The two journal files */
+    SQLITE_PTRSIZE +                     /* Space to hold a pointer */
+    4 +                                  /* Database prefix */
+    nPathname + 1 +                      /* database filename */
+    nUriByte +                           /* query parameters */
+    nPathname + 8 + 1 +                  /* Journal filename */
+#ifndef SQLITE_OMIT_WAL
+    nPathname + 4 + 1 +                  /* WAL filename */
+#endif
+    3                                    /* Terminator */
+  );
+  assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
+  if( !pPtr ){
+    sqlite3DbFree(0, zPathname);
+    return SQLITE_NOMEM_BKPT;
+  }
+  pPager = (Pager*)pPtr;                  pPtr += ROUND8(sizeof(*pPager));
+  pPager->pPCache = (PCache*)pPtr;        pPtr += ROUND8(pcacheSize);
+  pPager->fd = (sqlite3_file*)pPtr;       pPtr += ROUND8(pVfs->szOsFile);
+  pPager->sjfd = (sqlite3_file*)pPtr;     pPtr += journalFileSize;
+  pPager->jfd =  (sqlite3_file*)pPtr;     pPtr += journalFileSize;
+  assert( EIGHT_BYTE_ALIGNMENT(pPager->jfd) );
+  memcpy(pPtr, &pPager, SQLITE_PTRSIZE);  pPtr += SQLITE_PTRSIZE;
+
+  /* Fill in the Pager.zFilename and pPager.zQueryParam fields */
+                                          pPtr += 4;  /* Skip zero prefix */
+  pPager->zFilename = (char*)pPtr;
+  if( nPathname>0 ){
+    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname + 1;
+    if( zUri ){
+      memcpy(pPtr, zUri, nUriByte);       pPtr += nUriByte;
+    }else{
+                                          pPtr++;
+    }
+  }
+
+
+  /* Fill in Pager.zJournal */
+  if( nPathname>0 ){
+    pPager->zJournal = (char*)pPtr;
+    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname;
+    memcpy(pPtr, "-journal",8);           pPtr += 8 + 1;
+#ifdef SQLITE_ENABLE_8_3_NAMES
+    sqlite3FileSuffix3(zFilename,pPager->zJournal);
+    pPtr = (u8*)(pPager->zJournal + sqlite3Strlen30(pPager->zJournal)+1);
+#endif
+  }else{
+    pPager->zJournal = 0;
+  }
+
+#ifndef SQLITE_OMIT_WAL
+  /* Fill in Pager.zWal */
+  if( nPathname>0 ){
+    pPager->zWal = (char*)pPtr;
+    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname;
+    memcpy(pPtr, "-wal", 4);              pPtr += 4 + 1;
+#ifdef SQLITE_ENABLE_8_3_NAMES
+    sqlite3FileSuffix3(zFilename, pPager->zWal);
+    pPtr = (u8*)(pPager->zWal + sqlite3Strlen30(pPager->zWal)+1);
+#endif
+  }else{
+    pPager->zWal = 0;
+  }
+#endif
+  (void)pPtr;  /* Suppress warning about unused pPtr value */
+
+  if( nPathname ) sqlite3DbFree(0, zPathname);
+  pPager->pVfs = pVfs;
+  pPager->vfsFlags = vfsFlags;
+
+  /* Open the pager file.
+  */
+  if( zFilename && zFilename[0] ){
+    int fout = 0;                    /* VFS flags returned by xOpen() */
+    rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd, vfsFlags, &fout);
+    assert( !memDb );
+    pPager->memVfs = memJM = (fout&SQLITE_OPEN_MEMORY)!=0;
+    readOnly = (fout&SQLITE_OPEN_READONLY)!=0;
+
+    /* If the file was successfully opened for read/write access,
+    ** choose a default page size in case we have to create the
+    ** database file. The default page size is the maximum of:
+    **
+    **    + SQLITE_DEFAULT_PAGE_SIZE,
+    **    + The value returned by sqlite3OsSectorSize()
+    **    + The largest page size that can be written atomically.
+    */
+    if( rc==SQLITE_OK ){
+      int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
+      if( !readOnly ){
+        setSectorSize(pPager);
+        assert(SQLITE_DEFAULT_PAGE_SIZE<=SQLITE_MAX_DEFAULT_PAGE_SIZE);
+        if( szPageDflt<pPager->sectorSize ){
+          if( pPager->sectorSize>SQLITE_MAX_DEFAULT_PAGE_SIZE ){
+            szPageDflt = SQLITE_MAX_DEFAULT_PAGE_SIZE;
+          }else{
+            szPageDflt = (u32)pPager->sectorSize;
+          }
+        }
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+        {
+          int ii;
+          assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
+          assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
+          assert(SQLITE_MAX_DEFAULT_PAGE_SIZE<=65536);
+          for(ii=szPageDflt; ii<=SQLITE_MAX_DEFAULT_PAGE_SIZE; ii=ii*2){
+            if( iDc&(SQLITE_IOCAP_ATOMIC|(ii>>8)) ){
+              szPageDflt = ii;
+            }
+          }
+        }
+#endif
+      }
+      pPager->noLock = sqlite3_uri_boolean(pPager->zFilename, "nolock", 0);
+      if( (iDc & SQLITE_IOCAP_IMMUTABLE)!=0
+       || sqlite3_uri_boolean(pPager->zFilename, "immutable", 0) ){
+          vfsFlags |= SQLITE_OPEN_READONLY;
+          goto act_like_temp_file;
+      }
+    }
+  }else{
+    /* If a temporary file is requested, it is not opened immediately.
+    ** In this case we accept the default page size and delay actually
+    ** opening the file until the first call to OsWrite().
+    **
+    ** This branch is also run for an in-memory database. An in-memory
+    ** database is the same as a temp-file that is never written out to
+    ** disk and uses an in-memory rollback journal.
+    **
+    ** This branch also runs for files marked as immutable.
+    */
+act_like_temp_file:
+    tempFile = 1;
+    pPager->eState = PAGER_READER;     /* Pretend we already have a lock */
+    pPager->eLock = EXCLUSIVE_LOCK;    /* Pretend we are in EXCLUSIVE mode */
+    pPager->noLock = 1;                /* Do no locking */
+    readOnly = (vfsFlags&SQLITE_OPEN_READONLY);
+  }
+
+  /* The following call to PagerSetPagesize() serves to set the value of
+  ** Pager.pageSize and to allocate the Pager.pTmpSpace buffer.
+  */
+  if( rc==SQLITE_OK ){
+    assert( pPager->memDb==0 );
+    rc = sqlite3PagerSetPagesize(pPager, &szPageDflt, -1);
+    testcase( rc!=SQLITE_OK );
+  }
+
+  /* Initialize the PCache object. */
+  if( rc==SQLITE_OK ){
+    nExtra = ROUND8(nExtra);
+    assert( nExtra>=8 && nExtra<1000 );
+    rc = sqlite3PcacheOpen(szPageDflt, nExtra, !memDb,
+                       !memDb?pagerStress:0, (void *)pPager, pPager->pPCache);
+  }
+
+  /* If an error occurred above, free the  Pager structure and close the file.
+  */
+  if( rc!=SQLITE_OK ){
+    sqlite3OsClose(pPager->fd);
+    sqlite3PageFree(pPager->pTmpSpace);
+    sqlite3_free(pPager);
+    return rc;
+  }
+
+  PAGERTRACE(("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename));
+  IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename))
+
+  pPager->useJournal = (u8)useJournal;
+  /* pPager->stmtOpen = 0; */
+  /* pPager->stmtInUse = 0; */
+  /* pPager->nRef = 0; */
+  /* pPager->stmtSize = 0; */
+  /* pPager->stmtJSize = 0; */
+  /* pPager->nPage = 0; */
+  pPager->mxPgno = SQLITE_MAX_PAGE_COUNT;
+  /* pPager->state = PAGER_UNLOCK; */
+  /* pPager->errMask = 0; */
+  pPager->tempFile = (u8)tempFile;
+  assert( tempFile==PAGER_LOCKINGMODE_NORMAL
+          || tempFile==PAGER_LOCKINGMODE_EXCLUSIVE );
+  assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
+  pPager->exclusiveMode = (u8)tempFile;
+  pPager->changeCountDone = pPager->tempFile;
+  pPager->memDb = (u8)memDb;
+  pPager->readOnly = (u8)readOnly;
+  assert( useJournal || pPager->tempFile );
+  sqlite3PagerSetFlags(pPager, (SQLITE_DEFAULT_SYNCHRONOUS+1)|PAGER_CACHESPILL);
+  /* pPager->pFirst = 0; */
+  /* pPager->pFirstSynced = 0; */
+  /* pPager->pLast = 0; */
+  pPager->nExtra = (u16)nExtra;
+  pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
+  assert( isOpen(pPager->fd) || tempFile );
+  setSectorSize(pPager);
+  if( !useJournal ){
+    pPager->journalMode = PAGER_JOURNALMODE_OFF;
+  }else if( memDb || memJM ){
+    pPager->journalMode = PAGER_JOURNALMODE_MEMORY;
+  }
+  /* pPager->xBusyHandler = 0; */
+  /* pPager->pBusyHandlerArg = 0; */
+  pPager->xReiniter = xReinit;
+  setGetterMethod(pPager);
+  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
+  /* pPager->szMmap = SQLITE_DEFAULT_MMAP_SIZE // will be set by btree.c */
+
+  *ppPager = pPager;
+  return SQLITE_OK;
+}
+
+/*
+** Return the sqlite3_file for the main database given the name
+** of the corresponding WAL or Journal name as passed into
+** xOpen.
+*/
+SQLITE_API sqlite3_file *sqlite3_database_file_object(const char *zName){
+  Pager *pPager;
+  const char *p;
+  while( zName[-1]!=0 || zName[-2]!=0 || zName[-3]!=0 || zName[-4]!=0 ){
+    zName--;
+  }
+  p = zName - 4 - sizeof(Pager*);
+  assert( EIGHT_BYTE_ALIGNMENT(p) );
+  pPager = *(Pager**)p;
+  return pPager->fd;
+}
+
+
+/*
+** This function is called after transitioning from PAGER_UNLOCK to
+** PAGER_SHARED state. It tests if there is a hot journal present in
+** the file-system for the given pager. A hot journal is one that
+** needs to be played back. According to this function, a hot-journal
+** file exists if the following criteria are met:
+**
+**   * The journal file exists in the file system, and
+**   * No process holds a RESERVED or greater lock on the database file, and
+**   * The database file itself is greater than 0 bytes in size, and
+**   * The first byte of the journal file exists and is not 0x00.
+**
+** If the current size of the database file is 0 but a journal file
+** exists, that is probably an old journal left over from a prior
+** database with the same name. In this case the journal file is
+** just deleted using OsDelete, *pExists is set to 0 and SQLITE_OK
+** is returned.
+**
+** This routine does not check if there is a super-journal filename
+** at the end of the file. If there is, and that super-journal file
+** does not exist, then the journal file is not really hot. In this
+** case this routine will return a false-positive. The pager_playback()
+** routine will discover that the journal file is not really hot and
+** will not roll it back.
+**
+** If a hot-journal file is found to exist, *pExists is set to 1 and
+** SQLITE_OK returned. If no hot-journal file is present, *pExists is
+** set to 0 and SQLITE_OK returned. If an IO error occurs while trying
+** to determine whether or not a hot-journal file exists, the IO error
+** code is returned and the value of *pExists is undefined.
+*/
+static int hasHotJournal(Pager *pPager, int *pExists){
+  sqlite3_vfs * const pVfs = pPager->pVfs;
+  int rc = SQLITE_OK;           /* Return code */
+  int exists = 1;               /* True if a journal file is present */
+  int jrnlOpen = !!isOpen(pPager->jfd);
+
+  assert( pPager->useJournal );
+  assert( isOpen(pPager->fd) );
+  assert( pPager->eState==PAGER_OPEN );
+
+  assert( jrnlOpen==0 || ( sqlite3OsDeviceCharacteristics(pPager->jfd) &
+    SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
+  ));
+
+  *pExists = 0;
+  if( !jrnlOpen ){
+    rc = sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &exists);
+  }
+  if( rc==SQLITE_OK && exists ){
+    int locked = 0;             /* True if some process holds a RESERVED lock */
+
+    /* Race condition here:  Another process might have been holding the
+    ** the RESERVED lock and have a journal open at the sqlite3OsAccess()
+    ** call above, but then delete the journal and drop the lock before
+    ** we get to the following sqlite3OsCheckReservedLock() call.  If that
+    ** is the case, this routine might think there is a hot journal when
+    ** in fact there is none.  This results in a false-positive which will
+    ** be dealt with by the playback routine.  Ticket #3883.
+    */
+    rc = sqlite3OsCheckReservedLock(pPager->fd, &locked);
+    if( rc==SQLITE_OK && !locked ){
+      Pgno nPage;                 /* Number of pages in database file */
+
+      assert( pPager->tempFile==0 );
+      rc = pagerPagecount(pPager, &nPage);
+      if( rc==SQLITE_OK ){
+        /* If the database is zero pages in size, that means that either (1) the
+        ** journal is a remnant from a prior database with the same name where
+        ** the database file but not the journal was deleted, or (2) the initial
+        ** transaction that populates a new database is being rolled back.
+        ** In either case, the journal file can be deleted.  However, take care
+        ** not to delete the journal file if it is already open due to
+        ** journal_mode=PERSIST.
+        */
+        if( nPage==0 && !jrnlOpen ){
+          sqlite3BeginBenignMalloc();
+          if( pagerLockDb(pPager, RESERVED_LOCK)==SQLITE_OK ){
+            sqlite3OsDelete(pVfs, pPager->zJournal, 0);
+            if( !pPager->exclusiveMode ) pagerUnlockDb(pPager, SHARED_LOCK);
+          }
+          sqlite3EndBenignMalloc();
+        }else{
+          /* The journal file exists and no other connection has a reserved
+          ** or greater lock on the database file. Now check that there is
+          ** at least one non-zero bytes at the start of the journal file.
+          ** If there is, then we consider this journal to be hot. If not,
+          ** it can be ignored.
+          */
+          if( !jrnlOpen ){
+            int f = SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL;
+            rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &f);
+          }
+          if( rc==SQLITE_OK ){
+            u8 first = 0;
+            rc = sqlite3OsRead(pPager->jfd, (void *)&first, 1, 0);
+            if( rc==SQLITE_IOERR_SHORT_READ ){
+              rc = SQLITE_OK;
+            }
+            if( !jrnlOpen ){
+              sqlite3OsClose(pPager->jfd);
+            }
+            *pExists = (first!=0);
+          }else if( rc==SQLITE_CANTOPEN ){
+            /* If we cannot open the rollback journal file in order to see if
+            ** it has a zero header, that might be due to an I/O error, or
+            ** it might be due to the race condition described above and in
+            ** ticket #3883.  Either way, assume that the journal is hot.
+            ** This might be a false positive.  But if it is, then the
+            ** automatic journal playback and recovery mechanism will deal
+            ** with it under an EXCLUSIVE lock where we do not need to
+            ** worry so much with race conditions.
+            */
+            *pExists = 1;
+            rc = SQLITE_OK;
+          }
+        }
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is called to obtain a shared lock on the database file.
+** It is illegal to call sqlite3PagerGet() until after this function
+** has been successfully called. If a shared-lock is already held when
+** this function is called, it is a no-op.
+**
+** The following operations are also performed by this function.
+**
+**   1) If the pager is currently in PAGER_OPEN state (no lock held
+**      on the database file), then an attempt is made to obtain a
+**      SHARED lock on the database file. Immediately after obtaining
+**      the SHARED lock, the file-system is checked for a hot-journal,
+**      which is played back if present. Following any hot-journal
+**      rollback, the contents of the cache are validated by checking
+**      the 'change-counter' field of the database file header and
+**      discarded if they are found to be invalid.
+**
+**   2) If the pager is running in exclusive-mode, and there are currently
+**      no outstanding references to any pages, and is in the error state,
+**      then an attempt is made to clear the error state by discarding
+**      the contents of the page cache and rolling back any open journal
+**      file.
+**
+** If everything is successful, SQLITE_OK is returned. If an IO error
+** occurs while locking the database, checking for a hot-journal file or
+** rolling back a journal file, the IO error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerSharedLock(Pager *pPager){
+  int rc = SQLITE_OK;                /* Return code */
+
+  /* This routine is only called from b-tree and only when there are no
+  ** outstanding pages. This implies that the pager state should either
+  ** be OPEN or READER. READER is only possible if the pager is or was in
+  ** exclusive access mode.  */
+  assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->eState==PAGER_OPEN || pPager->eState==PAGER_READER );
+  assert( pPager->errCode==SQLITE_OK );
+
+  if( !pagerUseWal(pPager) && pPager->eState==PAGER_OPEN ){
+    int bHotJournal = 1;          /* True if there exists a hot journal-file */
+
+    assert( !MEMDB );
+    assert( pPager->tempFile==0 || pPager->eLock==EXCLUSIVE_LOCK );
+
+    rc = pager_wait_on_lock(pPager, SHARED_LOCK);
+    if( rc!=SQLITE_OK ){
+      assert( pPager->eLock==NO_LOCK || pPager->eLock==UNKNOWN_LOCK );
+      goto failed;
+    }
+
+    /* If a journal file exists, and there is no RESERVED lock on the
+    ** database file, then it either needs to be played back or deleted.
+    */
+    if( pPager->eLock<=SHARED_LOCK ){
+      rc = hasHotJournal(pPager, &bHotJournal);
+    }
+    if( rc!=SQLITE_OK ){
+      goto failed;
+    }
+    if( bHotJournal ){
+      if( pPager->readOnly ){
+        rc = SQLITE_READONLY_ROLLBACK;
+        goto failed;
+      }
+
+      /* Get an EXCLUSIVE lock on the database file. At this point it is
+      ** important that a RESERVED lock is not obtained on the way to the
+      ** EXCLUSIVE lock. If it were, another process might open the
+      ** database file, detect the RESERVED lock, and conclude that the
+      ** database is safe to read while this process is still rolling the
+      ** hot-journal back.
+      **
+      ** Because the intermediate RESERVED lock is not requested, any
+      ** other process attempting to access the database file will get to
+      ** this point in the code and fail to obtain its own EXCLUSIVE lock
+      ** on the database file.
+      **
+      ** Unless the pager is in locking_mode=exclusive mode, the lock is
+      ** downgraded to SHARED_LOCK before this function returns.
+      */
+      rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
+      if( rc!=SQLITE_OK ){
+        goto failed;
+      }
+
+      /* If it is not already open and the file exists on disk, open the
+      ** journal for read/write access. Write access is required because
+      ** in exclusive-access mode the file descriptor will be kept open
+      ** and possibly used for a transaction later on. Also, write-access
+      ** is usually required to finalize the journal in journal_mode=persist
+      ** mode (and also for journal_mode=truncate on some systems).
+      **
+      ** If the journal does not exist, it usually means that some
+      ** other connection managed to get in and roll it back before
+      ** this connection obtained the exclusive lock above. Or, it
+      ** may mean that the pager was in the error-state when this
+      ** function was called and the journal file does not exist.
+      */
+      if( !isOpen(pPager->jfd) && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
+        sqlite3_vfs * const pVfs = pPager->pVfs;
+        int bExists;              /* True if journal file exists */
+        rc = sqlite3OsAccess(
+            pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &bExists);
+        if( rc==SQLITE_OK && bExists ){
+          int fout = 0;
+          int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
+          assert( !pPager->tempFile );
+          rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
+          assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
+          if( rc==SQLITE_OK && fout&SQLITE_OPEN_READONLY ){
+            rc = SQLITE_CANTOPEN_BKPT;
+            sqlite3OsClose(pPager->jfd);
+          }
+        }
+      }
+
+      /* Playback and delete the journal.  Drop the database write
+      ** lock and reacquire the read lock. Purge the cache before
+      ** playing back the hot-journal so that we don't end up with
+      ** an inconsistent cache.  Sync the hot journal before playing
+      ** it back since the process that crashed and left the hot journal
+      ** probably did not sync it and we are required to always sync
+      ** the journal before playing it back.
+      */
+      if( isOpen(pPager->jfd) ){
+        assert( rc==SQLITE_OK );
+        rc = pagerSyncHotJournal(pPager);
+        if( rc==SQLITE_OK ){
+          rc = pager_playback(pPager, !pPager->tempFile);
+          pPager->eState = PAGER_OPEN;
+        }
+      }else if( !pPager->exclusiveMode ){
+        pagerUnlockDb(pPager, SHARED_LOCK);
+      }
+
+      if( rc!=SQLITE_OK ){
+        /* This branch is taken if an error occurs while trying to open
+        ** or roll back a hot-journal while holding an EXCLUSIVE lock. The
+        ** pager_unlock() routine will be called before returning to unlock
+        ** the file. If the unlock attempt fails, then Pager.eLock must be
+        ** set to UNKNOWN_LOCK (see the comment above the #define for
+        ** UNKNOWN_LOCK above for an explanation).
+        **
+        ** In order to get pager_unlock() to do this, set Pager.eState to
+        ** PAGER_ERROR now. This is not actually counted as a transition
+        ** to ERROR state in the state diagram at the top of this file,
+        ** since we know that the same call to pager_unlock() will very
+        ** shortly transition the pager object to the OPEN state. Calling
+        ** assert_pager_state() would fail now, as it should not be possible
+        ** to be in ERROR state when there are zero outstanding page
+        ** references.
+        */
+        pager_error(pPager, rc);
+        goto failed;
+      }
+
+      assert( pPager->eState==PAGER_OPEN );
+      assert( (pPager->eLock==SHARED_LOCK)
+           || (pPager->exclusiveMode && pPager->eLock>SHARED_LOCK)
+      );
+    }
+
+    if( !pPager->tempFile && pPager->hasHeldSharedLock ){
+      /* The shared-lock has just been acquired then check to
+      ** see if the database has been modified.  If the database has changed,
+      ** flush the cache.  The hasHeldSharedLock flag prevents this from
+      ** occurring on the very first access to a file, in order to save a
+      ** single unnecessary sqlite3OsRead() call at the start-up.
+      **
+      ** Database changes are detected by looking at 15 bytes beginning
+      ** at offset 24 into the file.  The first 4 of these 16 bytes are
+      ** a 32-bit counter that is incremented with each change.  The
+      ** other bytes change randomly with each file change when
+      ** a codec is in use.
+      **
+      ** There is a vanishingly small chance that a change will not be
+      ** detected.  The chance of an undetected change is so small that
+      ** it can be neglected.
+      */
+      char dbFileVers[sizeof(pPager->dbFileVers)];
+
+      IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
+      rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
+      if( rc!=SQLITE_OK ){
+        if( rc!=SQLITE_IOERR_SHORT_READ ){
+          goto failed;
+        }
+        memset(dbFileVers, 0, sizeof(dbFileVers));
+      }
+
+      if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
+        pager_reset(pPager);
+
+        /* Unmap the database file. It is possible that external processes
+        ** may have truncated the database file and then extended it back
+        ** to its original size while this process was not holding a lock.
+        ** In this case there may exist a Pager.pMap mapping that appears
+        ** to be the right size but is not actually valid. Avoid this
+        ** possibility by unmapping the db here. */
+        if( USEFETCH(pPager) ){
+          sqlite3OsUnfetch(pPager->fd, 0, 0);
+        }
+      }
+    }
+
+    /* If there is a WAL file in the file-system, open this database in WAL
+    ** mode. Otherwise, the following function call is a no-op.
+    */
+    rc = pagerOpenWalIfPresent(pPager);
+#ifndef SQLITE_OMIT_WAL
+    assert( pPager->pWal==0 || rc==SQLITE_OK );
+#endif
+  }
+
+  if( pagerUseWal(pPager) ){
+    assert( rc==SQLITE_OK );
+    rc = pagerBeginReadTransaction(pPager);
+  }
+
+  if( pPager->tempFile==0 && pPager->eState==PAGER_OPEN && rc==SQLITE_OK ){
+    rc = pagerPagecount(pPager, &pPager->dbSize);
+  }
+
+ failed:
+  if( rc!=SQLITE_OK ){
+    assert( !MEMDB );
+    pager_unlock(pPager);
+    assert( pPager->eState==PAGER_OPEN );
+  }else{
+    pPager->eState = PAGER_READER;
+    pPager->hasHeldSharedLock = 1;
+  }
+  return rc;
+}
+
+/*
+** If the reference count has reached zero, rollback any active
+** transaction and unlock the pager.
+**
+** Except, in locking_mode=EXCLUSIVE when there is nothing to in
+** the rollback journal, the unlock is not performed and there is
+** nothing to rollback, so this routine is a no-op.
+*/
+static void pagerUnlockIfUnused(Pager *pPager){
+  if( sqlite3PcacheRefCount(pPager->pPCache)==0 ){
+    assert( pPager->nMmapOut==0 ); /* because page1 is never memory mapped */
+    pagerUnlockAndRollback(pPager);
+  }
+}
+
+/*
+** The page getter methods each try to acquire a reference to a
+** page with page number pgno. If the requested reference is
+** successfully obtained, it is copied to *ppPage and SQLITE_OK returned.
+**
+** There are different implementations of the getter method depending
+** on the current state of the pager.
+**
+**     getPageNormal()         --  The normal getter
+**     getPageError()          --  Used if the pager is in an error state
+**     getPageMmap()           --  Used if memory-mapped I/O is enabled
+**
+** If the requested page is already in the cache, it is returned.
+** Otherwise, a new page object is allocated and populated with data
+** read from the database file. In some cases, the pcache module may
+** choose not to allocate a new page object and may reuse an existing
+** object with no outstanding references.
+**
+** The extra data appended to a page is always initialized to zeros the
+** first time a page is loaded into memory. If the page requested is
+** already in the cache when this function is called, then the extra
+** data is left as it was when the page object was last used.
+**
+** If the database image is smaller than the requested page or if
+** the flags parameter contains the PAGER_GET_NOCONTENT bit and the
+** requested page is not already stored in the cache, then no
+** actual disk read occurs. In this case the memory image of the
+** page is initialized to all zeros.
+**
+** If PAGER_GET_NOCONTENT is true, it means that we do not care about
+** the contents of the page. This occurs in two scenarios:
+**
+**   a) When reading a free-list leaf page from the database, and
+**
+**   b) When a savepoint is being rolled back and we need to load
+**      a new page into the cache to be filled with the data read
+**      from the savepoint journal.
+**
+** If PAGER_GET_NOCONTENT is true, then the data returned is zeroed instead
+** of being read from the database. Additionally, the bits corresponding
+** to pgno in Pager.pInJournal (bitvec of pages already written to the
+** journal file) and the PagerSavepoint.pInSavepoint bitvecs of any open
+** savepoints are set. This means if the page is made writable at any
+** point in the future, using a call to sqlite3PagerWrite(), its contents
+** will not be journaled. This saves IO.
+**
+** The acquisition might fail for several reasons.  In all cases,
+** an appropriate error code is returned and *ppPage is set to NULL.
+**
+** See also sqlite3PagerLookup().  Both this routine and Lookup() attempt
+** to find a page in the in-memory cache first.  If the page is not already
+** in memory, this routine goes to disk to read it in whereas Lookup()
+** just returns 0.  This routine acquires a read-lock the first time it
+** has to go to disk, and could also playback an old journal if necessary.
+** Since Lookup() never goes to disk, it never has to deal with locks
+** or journal files.
+*/
+static int getPageNormal(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int flags           /* PAGER_GET_XXX flags */
+){
+  int rc = SQLITE_OK;
+  PgHdr *pPg;
+  u8 noContent;                   /* True if PAGER_GET_NOCONTENT is set */
+  sqlite3_pcache_page *pBase;
+
+  assert( pPager->errCode==SQLITE_OK );
+  assert( pPager->eState>=PAGER_READER );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->hasHeldSharedLock==1 );
+
+  if( pgno==0 ) return SQLITE_CORRUPT_BKPT;
+  pBase = sqlite3PcacheFetch(pPager->pPCache, pgno, 3);
+  if( pBase==0 ){
+    pPg = 0;
+    rc = sqlite3PcacheFetchStress(pPager->pPCache, pgno, &pBase);
+    if( rc!=SQLITE_OK ) goto pager_acquire_err;
+    if( pBase==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto pager_acquire_err;
+    }
+  }
+  pPg = *ppPage = sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pBase);
+  assert( pPg==(*ppPage) );
+  assert( pPg->pgno==pgno );
+  assert( pPg->pPager==pPager || pPg->pPager==0 );
+
+  noContent = (flags & PAGER_GET_NOCONTENT)!=0;
+  if( pPg->pPager && !noContent ){
+    /* In this case the pcache already contains an initialized copy of
+    ** the page. Return without further ado.  */
+    assert( pgno!=PAGER_SJ_PGNO(pPager) );
+    pPager->aStat[PAGER_STAT_HIT]++;
+    return SQLITE_OK;
+
+  }else{
+    /* The pager cache has created a new page. Its content needs to
+    ** be initialized. But first some error checks:
+    **
+    ** (*) obsolete.  Was: maximum page number is 2^31
+    ** (2) Never try to fetch the locking page
+    */
+    if( pgno==PAGER_SJ_PGNO(pPager) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto pager_acquire_err;
+    }
+
+    pPg->pPager = pPager;
+
+    assert( !isOpen(pPager->fd) || !MEMDB );
+    if( !isOpen(pPager->fd) || pPager->dbSize<pgno || noContent ){
+      if( pgno>pPager->mxPgno ){
+        rc = SQLITE_FULL;
+        if( pgno<=pPager->dbSize ){
+          sqlite3PcacheRelease(pPg);
+          pPg = 0;
+        }
+        goto pager_acquire_err;
+      }
+      if( noContent ){
+        /* Failure to set the bits in the InJournal bit-vectors is benign.
+        ** It merely means that we might do some extra work to journal a
+        ** page that does not need to be journaled.  Nevertheless, be sure
+        ** to test the case where a malloc error occurs while trying to set
+        ** a bit in a bit vector.
+        */
+        sqlite3BeginBenignMalloc();
+        if( pgno<=pPager->dbOrigSize ){
+          TESTONLY( rc = ) sqlite3BitvecSet(pPager->pInJournal, pgno);
+          testcase( rc==SQLITE_NOMEM );
+        }
+        TESTONLY( rc = ) addToSavepointBitvecs(pPager, pgno);
+        testcase( rc==SQLITE_NOMEM );
+        sqlite3EndBenignMalloc();
+      }
+      memset(pPg->pData, 0, pPager->pageSize);
+      IOTRACE(("ZERO %p %d\n", pPager, pgno));
+    }else{
+      assert( pPg->pPager==pPager );
+      pPager->aStat[PAGER_STAT_MISS]++;
+      rc = readDbPage(pPg);
+      if( rc!=SQLITE_OK ){
+        goto pager_acquire_err;
+      }
+    }
+    pager_set_pagehash(pPg);
+  }
+  return SQLITE_OK;
+
+pager_acquire_err:
+  assert( rc!=SQLITE_OK );
+  if( pPg ){
+    sqlite3PcacheDrop(pPg);
+  }
+  pagerUnlockIfUnused(pPager);
+  *ppPage = 0;
+  return rc;
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/* The page getter for when memory-mapped I/O is enabled */
+static int getPageMMap(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int flags           /* PAGER_GET_XXX flags */
+){
+  int rc = SQLITE_OK;
+  PgHdr *pPg = 0;
+  u32 iFrame = 0;                 /* Frame to read from WAL file */
+
+  /* It is acceptable to use a read-only (mmap) page for any page except
+  ** page 1 if there is no write-transaction open or the ACQUIRE_READONLY
+  ** flag was specified by the caller. And so long as the db is not a
+  ** temporary or in-memory database.  */
+  const int bMmapOk = (pgno>1
+   && (pPager->eState==PAGER_READER || (flags & PAGER_GET_READONLY))
+  );
+
+  assert( USEFETCH(pPager) );
+
+  /* Optimization note:  Adding the "pgno<=1" term before "pgno==0" here
+  ** allows the compiler optimizer to reuse the results of the "pgno>1"
+  ** test in the previous statement, and avoid testing pgno==0 in the
+  ** common case where pgno is large. */
+  if( pgno<=1 && pgno==0 ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  assert( pPager->eState>=PAGER_READER );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->hasHeldSharedLock==1 );
+  assert( pPager->errCode==SQLITE_OK );
+
+  if( bMmapOk && pagerUseWal(pPager) ){
+    rc = sqlite3WalFindFrame(pPager->pWal, pgno, &iFrame);
+    if( rc!=SQLITE_OK ){
+      *ppPage = 0;
+      return rc;
+    }
+  }
+  if( bMmapOk && iFrame==0 ){
+    void *pData = 0;
+    rc = sqlite3OsFetch(pPager->fd,
+        (i64)(pgno-1) * pPager->pageSize, pPager->pageSize, &pData
+    );
+    if( rc==SQLITE_OK && pData ){
+      if( pPager->eState>PAGER_READER || pPager->tempFile ){
+        pPg = sqlite3PagerLookup(pPager, pgno);
+      }
+      if( pPg==0 ){
+        rc = pagerAcquireMapPage(pPager, pgno, pData, &pPg);
+      }else{
+        sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1)*pPager->pageSize, pData);
+      }
+      if( pPg ){
+        assert( rc==SQLITE_OK );
+        *ppPage = pPg;
+        return SQLITE_OK;
+      }
+    }
+    if( rc!=SQLITE_OK ){
+      *ppPage = 0;
+      return rc;
+    }
+  }
+  return getPageNormal(pPager, pgno, ppPage, flags);
+}
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+
+/* The page getter method for when the pager is an error state */
+static int getPageError(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int flags           /* PAGER_GET_XXX flags */
+){
+  UNUSED_PARAMETER(pgno);
+  UNUSED_PARAMETER(flags);
+  assert( pPager->errCode!=SQLITE_OK );
+  *ppPage = 0;
+  return pPager->errCode;
+}
+
+
+/* Dispatch all page fetch requests to the appropriate getter method.
+*/
+SQLITE_PRIVATE int sqlite3PagerGet(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int flags           /* PAGER_GET_XXX flags */
+){
+#if 0   /* Trace page fetch by setting to 1 */
+  int rc;
+  printf("PAGE %u\n", pgno);
+  fflush(stdout);
+  rc = pPager->xGet(pPager, pgno, ppPage, flags);
+  if( rc ){
+    printf("PAGE %u failed with 0x%02x\n", pgno, rc);
+    fflush(stdout);
+  }
+  return rc;
+#else
+  /* Normal, high-speed version of sqlite3PagerGet() */
+  return pPager->xGet(pPager, pgno, ppPage, flags);
+#endif
+}
+
+/*
+** Acquire a page if it is already in the in-memory cache.  Do
+** not read the page from disk.  Return a pointer to the page,
+** or 0 if the page is not in cache.
+**
+** See also sqlite3PagerGet().  The difference between this routine
+** and sqlite3PagerGet() is that _get() will go to the disk and read
+** in the page if the page is not already in cache.  This routine
+** returns NULL if the page is not in cache or if a disk I/O error
+** has ever happened.
+*/
+SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
+  sqlite3_pcache_page *pPage;
+  assert( pPager!=0 );
+  assert( pgno!=0 );
+  assert( pPager->pPCache!=0 );
+  pPage = sqlite3PcacheFetch(pPager->pPCache, pgno, 0);
+  assert( pPage==0 || pPager->hasHeldSharedLock );
+  if( pPage==0 ) return 0;
+  return sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pPage);
+}
+
+/*
+** Release a page reference.
+**
+** The sqlite3PagerUnref() and sqlite3PagerUnrefNotNull() may only be used
+** if we know that the page being released is not the last reference to page1.
+** The btree layer always holds page1 open until the end, so these first
+** two routines can be used to release any page other than BtShared.pPage1.
+** The assert() at tag-20230419-2 proves that this constraint is always
+** honored.
+**
+** Use sqlite3PagerUnrefPageOne() to release page1.  This latter routine
+** checks the total number of outstanding pages and if the number of
+** pages reaches zero it drops the database lock.
+*/
+SQLITE_PRIVATE void sqlite3PagerUnrefNotNull(DbPage *pPg){
+  TESTONLY( Pager *pPager = pPg->pPager; )
+  assert( pPg!=0 );
+  if( pPg->flags & PGHDR_MMAP ){
+    assert( pPg->pgno!=1 );  /* Page1 is never memory mapped */
+    pagerReleaseMapPage(pPg);
+  }else{
+    sqlite3PcacheRelease(pPg);
+  }
+  /* Do not use this routine to release the last reference to page1 */
+  assert( sqlite3PcacheRefCount(pPager->pPCache)>0 ); /* tag-20230419-2 */
+}
+SQLITE_PRIVATE void sqlite3PagerUnref(DbPage *pPg){
+  if( pPg ) sqlite3PagerUnrefNotNull(pPg);
+}
+SQLITE_PRIVATE void sqlite3PagerUnrefPageOne(DbPage *pPg){
+  Pager *pPager;
+  assert( pPg!=0 );
+  assert( pPg->pgno==1 );
+  assert( (pPg->flags & PGHDR_MMAP)==0 ); /* Page1 is never memory mapped */
+  pPager = pPg->pPager;
+  sqlite3PcacheRelease(pPg);
+  pagerUnlockIfUnused(pPager);
+}
+
+/*
+** This function is called at the start of every write transaction.
+** There must already be a RESERVED or EXCLUSIVE lock on the database
+** file when this routine is called.
+**
+** Open the journal file for pager pPager and write a journal header
+** to the start of it. If there are active savepoints, open the sub-journal
+** as well. This function is only used when the journal file is being
+** opened to write a rollback log for a transaction. It is not used
+** when opening a hot journal file to roll it back.
+**
+** If the journal file is already open (as it may be in exclusive mode),
+** then this function just writes a journal header to the start of the
+** already open file.
+**
+** Whether or not the journal file is opened by this function, the
+** Pager.pInJournal bitvec structure is allocated.
+**
+** Return SQLITE_OK if everything is successful. Otherwise, return
+** SQLITE_NOMEM if the attempt to allocate Pager.pInJournal fails, or
+** an IO error code if opening or writing the journal file fails.
+*/
+static int pager_open_journal(Pager *pPager){
+  int rc = SQLITE_OK;                        /* Return code */
+  sqlite3_vfs * const pVfs = pPager->pVfs;   /* Local cache of vfs pointer */
+
+  assert( pPager->eState==PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->pInJournal==0 );
+
+  /* If already in the error state, this function is a no-op.  But on
+  ** the other hand, this routine is never called if we are already in
+  ** an error state. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
+
+  if( !pagerUseWal(pPager) && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
+    pPager->pInJournal = sqlite3BitvecCreate(pPager->dbSize);
+    if( pPager->pInJournal==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+
+    /* Open the journal file if it is not already open. */
+    if( !isOpen(pPager->jfd) ){
+      if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
+        sqlite3MemJournalOpen(pPager->jfd);
+      }else{
+        int flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE;
+        int nSpill;
+
+        if( pPager->tempFile ){
+          flags |= (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL);
+          flags |= SQLITE_OPEN_EXCLUSIVE;
+          nSpill = sqlite3Config.nStmtSpill;
+        }else{
+          flags |= SQLITE_OPEN_MAIN_JOURNAL;
+          nSpill = jrnlBufferSize(pPager);
+        }
+
+        /* Verify that the database still has the same name as it did when
+        ** it was originally opened. */
+        rc = databaseIsUnmoved(pPager);
+        if( rc==SQLITE_OK ){
+          rc = sqlite3JournalOpen (
+              pVfs, pPager->zJournal, pPager->jfd, flags, nSpill
+          );
+        }
+      }
+      assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
+    }
+
+
+    /* Write the first journal header to the journal file and open
+    ** the sub-journal if necessary.
+    */
+    if( rc==SQLITE_OK ){
+      /* TODO: Check if all of these are really required. */
+      pPager->nRec = 0;
+      pPager->journalOff = 0;
+      pPager->setSuper = 0;
+      pPager->journalHdr = 0;
+      rc = writeJournalHdr(pPager);
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3BitvecDestroy(pPager->pInJournal);
+    pPager->pInJournal = 0;
+    pPager->journalOff = 0;
+  }else{
+    assert( pPager->eState==PAGER_WRITER_LOCKED );
+    pPager->eState = PAGER_WRITER_CACHEMOD;
+  }
+
+  return rc;
+}
+
+/*
+** Begin a write-transaction on the specified pager object. If a
+** write-transaction has already been opened, this function is a no-op.
+**
+** If the exFlag argument is false, then acquire at least a RESERVED
+** lock on the database file. If exFlag is true, then acquire at least
+** an EXCLUSIVE lock. If such a lock is already held, no locking
+** functions need be called.
+**
+** If the subjInMemory argument is non-zero, then any sub-journal opened
+** within this transaction will be opened as an in-memory file. This
+** has no effect if the sub-journal is already opened (as it may be when
+** running in exclusive mode) or if the transaction does not require a
+** sub-journal. If the subjInMemory argument is zero, then any required
+** sub-journal is implemented in-memory if pPager is an in-memory database,
+** or using a temporary file otherwise.
+*/
+SQLITE_PRIVATE int sqlite3PagerBegin(Pager *pPager, int exFlag, int subjInMemory){
+  int rc = SQLITE_OK;
+
+  if( pPager->errCode ) return pPager->errCode;
+  assert( pPager->eState>=PAGER_READER && pPager->eState<PAGER_ERROR );
+  pPager->subjInMemory = (u8)subjInMemory;
+
+  if( pPager->eState==PAGER_READER ){
+    assert( pPager->pInJournal==0 );
+
+    if( pagerUseWal(pPager) ){
+      /* If the pager is configured to use locking_mode=exclusive, and an
+      ** exclusive lock on the database is not already held, obtain it now.
+      */
+      if( pPager->exclusiveMode && sqlite3WalExclusiveMode(pPager->pWal, -1) ){
+        rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        (void)sqlite3WalExclusiveMode(pPager->pWal, 1);
+      }
+
+      /* Grab the write lock on the log file. If successful, upgrade to
+      ** PAGER_RESERVED state. Otherwise, return an error code to the caller.
+      ** The busy-handler is not invoked if another connection already
+      ** holds the write-lock. If possible, the upper layer will call it.
+      */
+      rc = sqlite3WalBeginWriteTransaction(pPager->pWal);
+    }else{
+      /* Obtain a RESERVED lock on the database file. If the exFlag parameter
+      ** is true, then immediately upgrade this to an EXCLUSIVE lock. The
+      ** busy-handler callback can be used when upgrading to the EXCLUSIVE
+      ** lock, but not when obtaining the RESERVED lock.
+      */
+      rc = pagerLockDb(pPager, RESERVED_LOCK);
+      if( rc==SQLITE_OK && exFlag ){
+        rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      /* Change to WRITER_LOCKED state.
+      **
+      ** WAL mode sets Pager.eState to PAGER_WRITER_LOCKED or CACHEMOD
+      ** when it has an open transaction, but never to DBMOD or FINISHED.
+      ** This is because in those states the code to roll back savepoint
+      ** transactions may copy data from the sub-journal into the database
+      ** file as well as into the page cache. Which would be incorrect in
+      ** WAL mode.
+      */
+      pPager->eState = PAGER_WRITER_LOCKED;
+      pPager->dbHintSize = pPager->dbSize;
+      pPager->dbFileSize = pPager->dbSize;
+      pPager->dbOrigSize = pPager->dbSize;
+      pPager->journalOff = 0;
+    }
+
+    assert( rc==SQLITE_OK || pPager->eState==PAGER_READER );
+    assert( rc!=SQLITE_OK || pPager->eState==PAGER_WRITER_LOCKED );
+    assert( assert_pager_state(pPager) );
+  }
+
+  PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
+  return rc;
+}
+
+/*
+** Write page pPg onto the end of the rollback journal.
+*/
+static SQLITE_NOINLINE int pagerAddPageToRollbackJournal(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  int rc;
+  u32 cksum;
+  char *pData2;
+  i64 iOff = pPager->journalOff;
+
+  /* We should never write to the journal file the page that
+  ** contains the database locks.  The following assert verifies
+  ** that we do not. */
+  assert( pPg->pgno!=PAGER_SJ_PGNO(pPager) );
+
+  assert( pPager->journalHdr<=pPager->journalOff );
+  pData2 = pPg->pData;
+  cksum = pager_cksum(pPager, (u8*)pData2);
+
+  /* Even if an IO or diskfull error occurs while journalling the
+  ** page in the block above, set the need-sync flag for the page.
+  ** Otherwise, when the transaction is rolled back, the logic in
+  ** playback_one_page() will think that the page needs to be restored
+  ** in the database file. And if an IO error occurs while doing so,
+  ** then corruption may follow.
+  */
+  pPg->flags |= PGHDR_NEED_SYNC;
+
+  rc = write32bits(pPager->jfd, iOff, pPg->pgno);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize, iOff+4);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = write32bits(pPager->jfd, iOff+pPager->pageSize+4, cksum);
+  if( rc!=SQLITE_OK ) return rc;
+
+  IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno,
+           pPager->journalOff, pPager->pageSize));
+  PAGER_INCR(sqlite3_pager_writej_count);
+  PAGERTRACE(("JOURNAL %d page %d needSync=%d hash(%08x)\n",
+       PAGERID(pPager), pPg->pgno,
+       ((pPg->flags&PGHDR_NEED_SYNC)?1:0), pager_pagehash(pPg)));
+
+  pPager->journalOff += 8 + pPager->pageSize;
+  pPager->nRec++;
+  assert( pPager->pInJournal!=0 );
+  rc = sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
+  testcase( rc==SQLITE_NOMEM );
+  assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+  rc |= addToSavepointBitvecs(pPager, pPg->pgno);
+  assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+  return rc;
+}
+
+/*
+** Mark a single data page as writeable. The page is written into the
+** main journal or sub-journal as required. If the page is written into
+** one of the journals, the corresponding bit is set in the
+** Pager.pInJournal bitvec and the PagerSavepoint.pInSavepoint bitvecs
+** of any open savepoints as appropriate.
+*/
+static int pager_write(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  int rc = SQLITE_OK;
+
+  /* This routine is not called unless a write-transaction has already
+  ** been started. The journal file may or may not be open at this point.
+  ** It is never called in the ERROR state.
+  */
+  assert( pPager->eState==PAGER_WRITER_LOCKED
+       || pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->errCode==0 );
+  assert( pPager->readOnly==0 );
+  CHECK_PAGE(pPg);
+
+  /* The journal file needs to be opened. Higher level routines have already
+  ** obtained the necessary locks to begin the write-transaction, but the
+  ** rollback journal might not yet be open. Open it now if this is the case.
+  **
+  ** This is done before calling sqlite3PcacheMakeDirty() on the page.
+  ** Otherwise, if it were done after calling sqlite3PcacheMakeDirty(), then
+  ** an error might occur and the pager would end up in WRITER_LOCKED state
+  ** with pages marked as dirty in the cache.
+  */
+  if( pPager->eState==PAGER_WRITER_LOCKED ){
+    rc = pager_open_journal(pPager);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD );
+  assert( assert_pager_state(pPager) );
+
+  /* Mark the page that is about to be modified as dirty. */
+  sqlite3PcacheMakeDirty(pPg);
+
+  /* If a rollback journal is in use, them make sure the page that is about
+  ** to change is in the rollback journal, or if the page is a new page off
+  ** then end of the file, make sure it is marked as PGHDR_NEED_SYNC.
+  */
+  assert( (pPager->pInJournal!=0) == isOpen(pPager->jfd) );
+  if( pPager->pInJournal!=0
+   && sqlite3BitvecTestNotNull(pPager->pInJournal, pPg->pgno)==0
+  ){
+    assert( pagerUseWal(pPager)==0 );
+    if( pPg->pgno<=pPager->dbOrigSize ){
+      rc = pagerAddPageToRollbackJournal(pPg);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }else{
+      if( pPager->eState!=PAGER_WRITER_DBMOD ){
+        pPg->flags |= PGHDR_NEED_SYNC;
+      }
+      PAGERTRACE(("APPEND %d page %d needSync=%d\n",
+              PAGERID(pPager), pPg->pgno,
+             ((pPg->flags&PGHDR_NEED_SYNC)?1:0)));
+    }
+  }
+
+  /* The PGHDR_DIRTY bit is set above when the page was added to the dirty-list
+  ** and before writing the page into the rollback journal.  Wait until now,
+  ** after the page has been successfully journalled, before setting the
+  ** PGHDR_WRITEABLE bit that indicates that the page can be safely modified.
+  */
+  pPg->flags |= PGHDR_WRITEABLE;
+
+  /* If the statement journal is open and the page is not in it,
+  ** then write the page into the statement journal.
+  */
+  if( pPager->nSavepoint>0 ){
+    rc = subjournalPageIfRequired(pPg);
+  }
+
+  /* Update the database size and return. */
+  if( pPager->dbSize<pPg->pgno ){
+    pPager->dbSize = pPg->pgno;
+  }
+  return rc;
+}
+
+/*
+** This is a variant of sqlite3PagerWrite() that runs when the sector size
+** is larger than the page size.  SQLite makes the (reasonable) assumption that
+** all bytes of a sector are written together by hardware.  Hence, all bytes of
+** a sector need to be journalled in case of a power loss in the middle of
+** a write.
+**
+** Usually, the sector size is less than or equal to the page size, in which
+** case pages can be individually written.  This routine only runs in the
+** exceptional case where the page size is smaller than the sector size.
+*/
+static SQLITE_NOINLINE int pagerWriteLargeSector(PgHdr *pPg){
+  int rc = SQLITE_OK;          /* Return code */
+  Pgno nPageCount;             /* Total number of pages in database file */
+  Pgno pg1;                    /* First page of the sector pPg is located on. */
+  int nPage = 0;               /* Number of pages starting at pg1 to journal */
+  int ii;                      /* Loop counter */
+  int needSync = 0;            /* True if any page has PGHDR_NEED_SYNC */
+  Pager *pPager = pPg->pPager; /* The pager that owns pPg */
+  Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);
+
+  /* Set the doNotSpill NOSYNC bit to 1. This is because we cannot allow
+  ** a journal header to be written between the pages journaled by
+  ** this function.
+  */
+  assert( !MEMDB );
+  assert( (pPager->doNotSpill & SPILLFLAG_NOSYNC)==0 );
+  pPager->doNotSpill |= SPILLFLAG_NOSYNC;
+
+  /* This trick assumes that both the page-size and sector-size are
+  ** an integer power of 2. It sets variable pg1 to the identifier
+  ** of the first page of the sector pPg is located on.
+  */
+  pg1 = ((pPg->pgno-1) & ~(nPagePerSector-1)) + 1;
+
+  nPageCount = pPager->dbSize;
+  if( pPg->pgno>nPageCount ){
+    nPage = (pPg->pgno - pg1)+1;
+  }else if( (pg1+nPagePerSector-1)>nPageCount ){
+    nPage = nPageCount+1-pg1;
+  }else{
+    nPage = nPagePerSector;
+  }
+  assert(nPage>0);
+  assert(pg1<=pPg->pgno);
+  assert((pg1+nPage)>pPg->pgno);
+
+  for(ii=0; ii<nPage && rc==SQLITE_OK; ii++){
+    Pgno pg = pg1+ii;
+    PgHdr *pPage;
+    if( pg==pPg->pgno || !sqlite3BitvecTest(pPager->pInJournal, pg) ){
+      if( pg!=PAGER_SJ_PGNO(pPager) ){
+        rc = sqlite3PagerGet(pPager, pg, &pPage, 0);
+        if( rc==SQLITE_OK ){
+          rc = pager_write(pPage);
+          if( pPage->flags&PGHDR_NEED_SYNC ){
+            needSync = 1;
+          }
+          sqlite3PagerUnrefNotNull(pPage);
+        }
+      }
+    }else if( (pPage = sqlite3PagerLookup(pPager, pg))!=0 ){
+      if( pPage->flags&PGHDR_NEED_SYNC ){
+        needSync = 1;
+      }
+      sqlite3PagerUnrefNotNull(pPage);
+    }
+  }
+
+  /* If the PGHDR_NEED_SYNC flag is set for any of the nPage pages
+  ** starting at pg1, then it needs to be set for all of them. Because
+  ** writing to any of these nPage pages may damage the others, the
+  ** journal file must contain sync()ed copies of all of them
+  ** before any of them can be written out to the database file.
+  */
+  if( rc==SQLITE_OK && needSync ){
+    assert( !MEMDB );
+    for(ii=0; ii<nPage; ii++){
+      PgHdr *pPage = sqlite3PagerLookup(pPager, pg1+ii);
+      if( pPage ){
+        pPage->flags |= PGHDR_NEED_SYNC;
+        sqlite3PagerUnrefNotNull(pPage);
+      }
+    }
+  }
+
+  assert( (pPager->doNotSpill & SPILLFLAG_NOSYNC)!=0 );
+  pPager->doNotSpill &= ~SPILLFLAG_NOSYNC;
+  return rc;
+}
+
+/*
+** Mark a data page as writeable. This routine must be called before
+** making changes to a page. The caller must check the return value
+** of this function and be careful not to change any page data unless
+** this routine returns SQLITE_OK.
+**
+** The difference between this function and pager_write() is that this
+** function also deals with the special case where 2 or more pages
+** fit on a single disk sector. In this case all co-resident pages
+** must have been written to the journal file before returning.
+**
+** If an error occurs, SQLITE_NOMEM or an IO error code is returned
+** as appropriate. Otherwise, SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3PagerWrite(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  assert( (pPg->flags & PGHDR_MMAP)==0 );
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
+  if( (pPg->flags & PGHDR_WRITEABLE)!=0 && pPager->dbSize>=pPg->pgno ){
+    if( pPager->nSavepoint ) return subjournalPageIfRequired(pPg);
+    return SQLITE_OK;
+  }else if( pPager->errCode ){
+    return pPager->errCode;
+  }else if( pPager->sectorSize > (u32)pPager->pageSize ){
+    assert( pPager->tempFile==0 );
+    return pagerWriteLargeSector(pPg);
+  }else{
+    return pager_write(pPg);
+  }
+}
+
+/*
+** Return TRUE if the page given in the argument was previously passed
+** to sqlite3PagerWrite().  In other words, return TRUE if it is ok
+** to change the content of the page.
+*/
+#ifndef NDEBUG
+SQLITE_PRIVATE int sqlite3PagerIswriteable(DbPage *pPg){
+  return pPg->flags & PGHDR_WRITEABLE;
+}
+#endif
+
+/*
+** A call to this routine tells the pager that it is not necessary to
+** write the information on page pPg back to the disk, even though
+** that page might be marked as dirty.  This happens, for example, when
+** the page has been added as a leaf of the freelist and so its
+** content no longer matters.
+**
+** The overlying software layer calls this routine when all of the data
+** on the given page is unused. The pager marks the page as clean so
+** that it does not get written to disk.
+**
+** Tests show that this optimization can quadruple the speed of large
+** DELETE operations.
+**
+** This optimization cannot be used with a temp-file, as the page may
+** have been dirty at the start of the transaction. In that case, if
+** memory pressure forces page pPg out of the cache, the data does need
+** to be written out to disk so that it may be read back in if the
+** current transaction is rolled back.
+*/
+SQLITE_PRIVATE void sqlite3PagerDontWrite(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  if( !pPager->tempFile && (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){
+    PAGERTRACE(("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager)));
+    IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
+    pPg->flags |= PGHDR_DONT_WRITE;
+    pPg->flags &= ~PGHDR_WRITEABLE;
+    testcase( pPg->flags & PGHDR_NEED_SYNC );
+    pager_set_pagehash(pPg);
+  }
+}
+
+/*
+** This routine is called to increment the value of the database file
+** change-counter, stored as a 4-byte big-endian integer starting at
+** byte offset 24 of the pager file.  The secondary change counter at
+** 92 is also updated, as is the SQLite version number at offset 96.
+**
+** But this only happens if the pPager->changeCountDone flag is false.
+** To avoid excess churning of page 1, the update only happens once.
+** See also the pager_write_changecounter() routine that does an
+** unconditional update of the change counters.
+**
+** If the isDirectMode flag is zero, then this is done by calling
+** sqlite3PagerWrite() on page 1, then modifying the contents of the
+** page data. In this case the file will be updated when the current
+** transaction is committed.
+**
+** The isDirectMode flag may only be non-zero if the library was compiled
+** with the SQLITE_ENABLE_ATOMIC_WRITE macro defined. In this case,
+** if isDirect is non-zero, then the database file is updated directly
+** by writing an updated version of page 1 using a call to the
+** sqlite3OsWrite() function.
+*/
+static int pager_incr_changecounter(Pager *pPager, int isDirectMode){
+  int rc = SQLITE_OK;
+
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* Declare and initialize constant integer 'isDirect'. If the
+  ** atomic-write optimization is enabled in this build, then isDirect
+  ** is initialized to the value passed as the isDirectMode parameter
+  ** to this function. Otherwise, it is always set to zero.
+  **
+  ** The idea is that if the atomic-write optimization is not
+  ** enabled at compile time, the compiler can omit the tests of
+  ** 'isDirect' below, as well as the block enclosed in the
+  ** "if( isDirect )" condition.
+  */
+#ifndef SQLITE_ENABLE_ATOMIC_WRITE
+# define DIRECT_MODE 0
+  assert( isDirectMode==0 );
+  UNUSED_PARAMETER(isDirectMode);
+#else
+# define DIRECT_MODE isDirectMode
+#endif
+
+  if( !pPager->changeCountDone && pPager->dbSize>0 ){
+    PgHdr *pPgHdr;                /* Reference to page 1 */
+
+    assert( !pPager->tempFile && isOpen(pPager->fd) );
+
+    /* Open page 1 of the file for writing. */
+    rc = sqlite3PagerGet(pPager, 1, &pPgHdr, 0);
+    assert( pPgHdr==0 || rc==SQLITE_OK );
+
+    /* If page one was fetched successfully, and this function is not
+    ** operating in direct-mode, make page 1 writable.  When not in
+    ** direct mode, page 1 is always held in cache and hence the PagerGet()
+    ** above is always successful - hence the ALWAYS on rc==SQLITE_OK.
+    */
+    if( !DIRECT_MODE && ALWAYS(rc==SQLITE_OK) ){
+      rc = sqlite3PagerWrite(pPgHdr);
+    }
+
+    if( rc==SQLITE_OK ){
+      /* Actually do the update of the change counter */
+      pager_write_changecounter(pPgHdr);
+
+      /* If running in direct mode, write the contents of page 1 to the file. */
+      if( DIRECT_MODE ){
+        const void *zBuf;
+        assert( pPager->dbFileSize>0 );
+        zBuf = pPgHdr->pData;
+        if( rc==SQLITE_OK ){
+          rc = sqlite3OsWrite(pPager->fd, zBuf, pPager->pageSize, 0);
+          pPager->aStat[PAGER_STAT_WRITE]++;
+        }
+        if( rc==SQLITE_OK ){
+          /* Update the pager's copy of the change-counter. Otherwise, the
+          ** next time a read transaction is opened the cache will be
+          ** flushed (as the change-counter values will not match).  */
+          const void *pCopy = (const void *)&((const char *)zBuf)[24];
+          memcpy(&pPager->dbFileVers, pCopy, sizeof(pPager->dbFileVers));
+          pPager->changeCountDone = 1;
+        }
+      }else{
+        pPager->changeCountDone = 1;
+      }
+    }
+
+    /* Release the page reference. */
+    sqlite3PagerUnref(pPgHdr);
+  }
+  return rc;
+}
+
+/*
+** Sync the database file to disk. This is a no-op for in-memory databases
+** or pages with the Pager.noSync flag set.
+**
+** If successful, or if called on a pager for which it is a no-op, this
+** function returns SQLITE_OK. Otherwise, an IO error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager, const char *zSuper){
+  int rc = SQLITE_OK;
+  void *pArg = (void*)zSuper;
+  rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_SYNC, pArg);
+  if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+  if( rc==SQLITE_OK && !pPager->noSync ){
+    assert( !MEMDB );
+    rc = sqlite3OsSync(pPager->fd, pPager->syncFlags);
+  }
+  return rc;
+}
+
+/*
+** This function may only be called while a write-transaction is active in
+** rollback. If the connection is in WAL mode, this call is a no-op.
+** Otherwise, if the connection does not already have an EXCLUSIVE lock on
+** the database file, an attempt is made to obtain one.
+**
+** If the EXCLUSIVE lock is already held or the attempt to obtain it is
+** successful, or the connection is in WAL mode, SQLITE_OK is returned.
+** Otherwise, either SQLITE_BUSY or an SQLITE_IOERR_XXX error code is
+** returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerExclusiveLock(Pager *pPager){
+  int rc = pPager->errCode;
+  assert( assert_pager_state(pPager) );
+  if( rc==SQLITE_OK ){
+    assert( pPager->eState==PAGER_WRITER_CACHEMOD
+         || pPager->eState==PAGER_WRITER_DBMOD
+         || pPager->eState==PAGER_WRITER_LOCKED
+    );
+    assert( assert_pager_state(pPager) );
+    if( 0==pagerUseWal(pPager) ){
+      rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
+    }
+  }
+  return rc;
+}
+
+/*
+** Sync the database file for the pager pPager. zSuper points to the name
+** of a super-journal file that should be written into the individual
+** journal file. zSuper may be NULL, which is interpreted as no
+** super-journal (a single database transaction).
+**
+** This routine ensures that:
+**
+**   * The database file change-counter is updated,
+**   * the journal is synced (unless the atomic-write optimization is used),
+**   * all dirty pages are written to the database file,
+**   * the database file is truncated (if required), and
+**   * the database file synced.
+**
+** The only thing that remains to commit the transaction is to finalize
+** (delete, truncate or zero the first part of) the journal file (or
+** delete the super-journal file if specified).
+**
+** Note that if zSuper==NULL, this does not overwrite a previous value
+** passed to an sqlite3PagerCommitPhaseOne() call.
+**
+** If the final parameter - noSync - is true, then the database file itself
+** is not synced. The caller must call sqlite3PagerSync() directly to
+** sync the database file before calling CommitPhaseTwo() to delete the
+** journal file in this case.
+*/
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(
+  Pager *pPager,                  /* Pager object */
+  const char *zSuper,            /* If not NULL, the super-journal name */
+  int noSync                      /* True to omit the xSync on the db file */
+){
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( pPager->eState==PAGER_WRITER_LOCKED
+       || pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+       || pPager->eState==PAGER_ERROR
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* If a prior error occurred, report that error again. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
+
+  /* Provide the ability to easily simulate an I/O error during testing */
+  if( sqlite3FaultSim(400) ) return SQLITE_IOERR;
+
+  PAGERTRACE(("DATABASE SYNC: File=%s zSuper=%s nSize=%d\n",
+      pPager->zFilename, zSuper, pPager->dbSize));
+
+  /* If no database changes have been made, return early. */
+  if( pPager->eState<PAGER_WRITER_CACHEMOD ) return SQLITE_OK;
+
+  assert( MEMDB==0 || pPager->tempFile );
+  assert( isOpen(pPager->fd) || pPager->tempFile );
+  if( 0==pagerFlushOnCommit(pPager, 1) ){
+    /* If this is an in-memory db, or no pages have been written to, or this
+    ** function has already been called, it is mostly a no-op.  However, any
+    ** backup in progress needs to be restarted.  */
+    sqlite3BackupRestart(pPager->pBackup);
+  }else{
+    PgHdr *pList;
+    if( pagerUseWal(pPager) ){
+      PgHdr *pPageOne = 0;
+      pList = sqlite3PcacheDirtyList(pPager->pPCache);
+      if( pList==0 ){
+        /* Must have at least one page for the WAL commit flag.
+        ** Ticket [2d1a5c67dfc2363e44f29d9bbd57f] 2011-05-18 */
+        rc = sqlite3PagerGet(pPager, 1, &pPageOne, 0);
+        pList = pPageOne;
+        pList->pDirty = 0;
+      }
+      assert( rc==SQLITE_OK );
+      if( ALWAYS(pList) ){
+        rc = pagerWalFrames(pPager, pList, pPager->dbSize, 1);
+      }
+      sqlite3PagerUnref(pPageOne);
+      if( rc==SQLITE_OK ){
+        sqlite3PcacheCleanAll(pPager->pPCache);
+      }
+    }else{
+      /* The bBatch boolean is true if the batch-atomic-write commit method
+      ** should be used.  No rollback journal is created if batch-atomic-write
+      ** is enabled.
+      */
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+      sqlite3_file *fd = pPager->fd;
+      int bBatch = zSuper==0    /* An SQLITE_IOCAP_BATCH_ATOMIC commit */
+        && (sqlite3OsDeviceCharacteristics(fd) & SQLITE_IOCAP_BATCH_ATOMIC)
+        && !pPager->noSync
+        && sqlite3JournalIsInMemory(pPager->jfd);
+#else
+#     define bBatch 0
+#endif
+
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+      /* The following block updates the change-counter. Exactly how it
+      ** does this depends on whether or not the atomic-update optimization
+      ** was enabled at compile time, and if this transaction meets the
+      ** runtime criteria to use the operation:
+      **
+      **    * The file-system supports the atomic-write property for
+      **      blocks of size page-size, and
+      **    * This commit is not part of a multi-file transaction, and
+      **    * Exactly one page has been modified and store in the journal file.
+      **
+      ** If the optimization was not enabled at compile time, then the
+      ** pager_incr_changecounter() function is called to update the change
+      ** counter in 'indirect-mode'. If the optimization is compiled in but
+      ** is not applicable to this transaction, call sqlite3JournalCreate()
+      ** to make sure the journal file has actually been created, then call
+      ** pager_incr_changecounter() to update the change-counter in indirect
+      ** mode.
+      **
+      ** Otherwise, if the optimization is both enabled and applicable,
+      ** then call pager_incr_changecounter() to update the change-counter
+      ** in 'direct' mode. In this case the journal file will never be
+      ** created for this transaction.
+      */
+      if( bBatch==0 ){
+        PgHdr *pPg;
+        assert( isOpen(pPager->jfd)
+            || pPager->journalMode==PAGER_JOURNALMODE_OFF
+            || pPager->journalMode==PAGER_JOURNALMODE_WAL
+            );
+        if( !zSuper && isOpen(pPager->jfd)
+         && pPager->journalOff==jrnlBufferSize(pPager)
+         && pPager->dbSize>=pPager->dbOrigSize
+         && (!(pPg = sqlite3PcacheDirtyList(pPager->pPCache)) || 0==pPg->pDirty)
+        ){
+          /* Update the db file change counter via the direct-write method. The
+          ** following call will modify the in-memory representation of page 1
+          ** to include the updated change counter and then write page 1
+          ** directly to the database file. Because of the atomic-write
+          ** property of the host file-system, this is safe.
+          */
+          rc = pager_incr_changecounter(pPager, 1);
+        }else{
+          rc = sqlite3JournalCreate(pPager->jfd);
+          if( rc==SQLITE_OK ){
+            rc = pager_incr_changecounter(pPager, 0);
+          }
+        }
+      }
+#else  /* SQLITE_ENABLE_ATOMIC_WRITE */
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+      if( zSuper ){
+        rc = sqlite3JournalCreate(pPager->jfd);
+        if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+        assert( bBatch==0 );
+      }
+#endif
+      rc = pager_incr_changecounter(pPager, 0);
+#endif /* !SQLITE_ENABLE_ATOMIC_WRITE */
+      if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+
+      /* Write the super-journal name into the journal file. If a
+      ** super-journal file name has already been written to the journal file,
+      ** or if zSuper is NULL (no super-journal), then this call is a no-op.
+      */
+      rc = writeSuperJournal(pPager, zSuper);
+      if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+
+      /* Sync the journal file and write all dirty pages to the database.
+      ** If the atomic-update optimization is being used, this sync will not
+      ** create the journal file or perform any real IO.
+      **
+      ** Because the change-counter page was just modified, unless the
+      ** atomic-update optimization is used it is almost certain that the
+      ** journal requires a sync here. However, in locking_mode=exclusive
+      ** on a system under memory pressure it is just possible that this is
+      ** not the case. In this case it is likely enough that the redundant
+      ** xSync() call will be changed to a no-op by the OS anyhow.
+      */
+      rc = syncJournal(pPager, 0);
+      if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+
+      pList = sqlite3PcacheDirtyList(pPager->pPCache);
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+      if( bBatch ){
+        rc = sqlite3OsFileControl(fd, SQLITE_FCNTL_BEGIN_ATOMIC_WRITE, 0);
+        if( rc==SQLITE_OK ){
+          rc = pager_write_pagelist(pPager, pList);
+          if( rc==SQLITE_OK && pPager->dbSize>pPager->dbFileSize ){
+            char *pTmp = pPager->pTmpSpace;
+            int szPage = (int)pPager->pageSize;
+            memset(pTmp, 0, szPage);
+            rc = sqlite3OsWrite(pPager->fd, pTmp, szPage,
+                      ((i64)pPager->dbSize*pPager->pageSize)-szPage);
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3OsFileControl(fd, SQLITE_FCNTL_COMMIT_ATOMIC_WRITE, 0);
+          }
+          if( rc!=SQLITE_OK ){
+            sqlite3OsFileControlHint(fd, SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE, 0);
+          }
+        }
+
+        if( (rc&0xFF)==SQLITE_IOERR && rc!=SQLITE_IOERR_NOMEM ){
+          rc = sqlite3JournalCreate(pPager->jfd);
+          if( rc!=SQLITE_OK ){
+            sqlite3OsClose(pPager->jfd);
+            goto commit_phase_one_exit;
+          }
+          bBatch = 0;
+        }else{
+          sqlite3OsClose(pPager->jfd);
+        }
+      }
+#endif /* SQLITE_ENABLE_BATCH_ATOMIC_WRITE */
+
+      if( bBatch==0 ){
+        rc = pager_write_pagelist(pPager, pList);
+      }
+      if( rc!=SQLITE_OK ){
+        assert( rc!=SQLITE_IOERR_BLOCKED );
+        goto commit_phase_one_exit;
+      }
+      sqlite3PcacheCleanAll(pPager->pPCache);
+
+      /* If the file on disk is smaller than the database image, use
+      ** pager_truncate to grow the file here. This can happen if the database
+      ** image was extended as part of the current transaction and then the
+      ** last page in the db image moved to the free-list. In this case the
+      ** last page is never written out to disk, leaving the database file
+      ** undersized. Fix this now if it is the case.  */
+      if( pPager->dbSize>pPager->dbFileSize ){
+        Pgno nNew = pPager->dbSize - (pPager->dbSize==PAGER_SJ_PGNO(pPager));
+        assert( pPager->eState==PAGER_WRITER_DBMOD );
+        rc = pager_truncate(pPager, nNew);
+        if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+      }
+
+      /* Finally, sync the database file. */
+      if( !noSync ){
+        rc = sqlite3PagerSync(pPager, zSuper);
+      }
+      IOTRACE(("DBSYNC %p\n", pPager))
+    }
+  }
+
+commit_phase_one_exit:
+  if( rc==SQLITE_OK && !pagerUseWal(pPager) ){
+    pPager->eState = PAGER_WRITER_FINISHED;
+  }
+  return rc;
+}
+
+
+/*
+** When this function is called, the database file has been completely
+** updated to reflect the changes made by the current transaction and
+** synced to disk. The journal file still exists in the file-system
+** though, and if a failure occurs at this point it will eventually
+** be used as a hot-journal and the current transaction rolled back.
+**
+** This function finalizes the journal file, either by deleting,
+** truncating or partially zeroing it, so that it cannot be used
+** for hot-journal rollback. Once this is done the transaction is
+** irrevocably committed.
+**
+** If an error occurs, an IO error code is returned and the pager
+** moves into the error state. Otherwise, SQLITE_OK is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager *pPager){
+  int rc = SQLITE_OK;                  /* Return code */
+
+  /* This routine should not be called if a prior error has occurred.
+  ** But if (due to a coding error elsewhere in the system) it does get
+  ** called, just return the same error code without doing anything. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
+  pPager->iDataVersion++;
+
+  assert( pPager->eState==PAGER_WRITER_LOCKED
+       || pPager->eState==PAGER_WRITER_FINISHED
+       || (pagerUseWal(pPager) && pPager->eState==PAGER_WRITER_CACHEMOD)
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* An optimization. If the database was not actually modified during
+  ** this transaction, the pager is running in exclusive-mode and is
+  ** using persistent journals, then this function is a no-op.
+  **
+  ** The start of the journal file currently contains a single journal
+  ** header with the nRec field set to 0. If such a journal is used as
+  ** a hot-journal during hot-journal rollback, 0 changes will be made
+  ** to the database file. So there is no need to zero the journal
+  ** header. Since the pager is in exclusive mode, there is no need
+  ** to drop any locks either.
+  */
+  if( pPager->eState==PAGER_WRITER_LOCKED
+   && pPager->exclusiveMode
+   && pPager->journalMode==PAGER_JOURNALMODE_PERSIST
+  ){
+    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) || !pPager->journalOff );
+    pPager->eState = PAGER_READER;
+    return SQLITE_OK;
+  }
+
+  PAGERTRACE(("COMMIT %d\n", PAGERID(pPager)));
+  rc = pager_end_transaction(pPager, pPager->setSuper, 1);
+  return pager_error(pPager, rc);
+}
+
+/*
+** If a write transaction is open, then all changes made within the
+** transaction are reverted and the current write-transaction is closed.
+** The pager falls back to PAGER_READER state if successful, or PAGER_ERROR
+** state if an error occurs.
+**
+** If the pager is already in PAGER_ERROR state when this function is called,
+** it returns Pager.errCode immediately. No work is performed in this case.
+**
+** Otherwise, in rollback mode, this function performs two functions:
+**
+**   1) It rolls back the journal file, restoring all database file and
+**      in-memory cache pages to the state they were in when the transaction
+**      was opened, and
+**
+**   2) It finalizes the journal file, so that it is not used for hot
+**      rollback at any point in the future.
+**
+** Finalization of the journal file (task 2) is only performed if the
+** rollback is successful.
+**
+** In WAL mode, all cache-entries containing data modified within the
+** current transaction are either expelled from the cache or reverted to
+** their pre-transaction state by re-reading data from the database or
+** WAL files. The WAL transaction is then closed.
+*/
+SQLITE_PRIVATE int sqlite3PagerRollback(Pager *pPager){
+  int rc = SQLITE_OK;                  /* Return code */
+  PAGERTRACE(("ROLLBACK %d\n", PAGERID(pPager)));
+
+  /* PagerRollback() is a no-op if called in READER or OPEN state. If
+  ** the pager is already in the ERROR state, the rollback is not
+  ** attempted here. Instead, the error code is returned to the caller.
+  */
+  assert( assert_pager_state(pPager) );
+  if( pPager->eState==PAGER_ERROR ) return pPager->errCode;
+  if( pPager->eState<=PAGER_READER ) return SQLITE_OK;
+
+  if( pagerUseWal(pPager) ){
+    int rc2;
+    rc = sqlite3PagerSavepoint(pPager, SAVEPOINT_ROLLBACK, -1);
+    rc2 = pager_end_transaction(pPager, pPager->setSuper, 0);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }else if( !isOpen(pPager->jfd) || pPager->eState==PAGER_WRITER_LOCKED ){
+    int eState = pPager->eState;
+    rc = pager_end_transaction(pPager, 0, 0);
+    if( !MEMDB && eState>PAGER_WRITER_LOCKED ){
+      /* This can happen using journal_mode=off. Move the pager to the error
+      ** state to indicate that the contents of the cache may not be trusted.
+      ** Any active readers will get SQLITE_ABORT.
+      */
+      pPager->errCode = SQLITE_ABORT;
+      pPager->eState = PAGER_ERROR;
+      setGetterMethod(pPager);
+      return rc;
+    }
+  }else{
+    rc = pager_playback(pPager, 0);
+  }
+
+  assert( pPager->eState==PAGER_READER || rc!=SQLITE_OK );
+  assert( rc==SQLITE_OK || rc==SQLITE_FULL || rc==SQLITE_CORRUPT
+          || rc==SQLITE_NOMEM || (rc&0xFF)==SQLITE_IOERR
+          || rc==SQLITE_CANTOPEN
+  );
+
+  /* If an error occurs during a ROLLBACK, we can no longer trust the pager
+  ** cache. So call pager_error() on the way out to make any error persistent.
+  */
+  return pager_error(pPager, rc);
+}
+
+/*
+** Return TRUE if the database file is opened read-only.  Return FALSE
+** if the database is (in theory) writable.
+*/
+SQLITE_PRIVATE u8 sqlite3PagerIsreadonly(Pager *pPager){
+  return pPager->readOnly;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Return the sum of the reference counts for all pages held by pPager.
+*/
+SQLITE_PRIVATE int sqlite3PagerRefcount(Pager *pPager){
+  return sqlite3PcacheRefCount(pPager->pPCache);
+}
+#endif
+
+/*
+** Return the approximate number of bytes of memory currently
+** used by the pager and its associated cache.
+*/
+SQLITE_PRIVATE int sqlite3PagerMemUsed(Pager *pPager){
+  int perPageSize = pPager->pageSize + pPager->nExtra
+    + (int)(sizeof(PgHdr) + 5*sizeof(void*));
+  return perPageSize*sqlite3PcachePagecount(pPager->pPCache)
+           + sqlite3MallocSize(pPager)
+           + pPager->pageSize;
+}
+
+/*
+** Return the number of references to the specified page.
+*/
+SQLITE_PRIVATE int sqlite3PagerPageRefcount(DbPage *pPage){
+  return sqlite3PcachePageRefcount(pPage);
+}
+
+#ifdef SQLITE_TEST
+/*
+** This routine is used for testing and analysis only.
+*/
+SQLITE_PRIVATE int *sqlite3PagerStats(Pager *pPager){
+  static int a[11];
+  a[0] = sqlite3PcacheRefCount(pPager->pPCache);
+  a[1] = sqlite3PcachePagecount(pPager->pPCache);
+  a[2] = sqlite3PcacheGetCachesize(pPager->pPCache);
+  a[3] = pPager->eState==PAGER_OPEN ? -1 : (int) pPager->dbSize;
+  a[4] = pPager->eState;
+  a[5] = pPager->errCode;
+  a[6] = (int)pPager->aStat[PAGER_STAT_HIT] & 0x7fffffff;
+  a[7] = (int)pPager->aStat[PAGER_STAT_MISS] & 0x7fffffff;
+  a[8] = 0;  /* Used to be pPager->nOvfl */
+  a[9] = pPager->nRead;
+  a[10] = (int)pPager->aStat[PAGER_STAT_WRITE] & 0x7fffffff;
+  return a;
+}
+#endif
+
+/*
+** Parameter eStat must be one of SQLITE_DBSTATUS_CACHE_HIT, _MISS, _WRITE,
+** or _WRITE+1.  The SQLITE_DBSTATUS_CACHE_WRITE+1 case is a translation
+** of SQLITE_DBSTATUS_CACHE_SPILL.  The _SPILL case is not contiguous because
+** it was added later.
+**
+** Before returning, *pnVal is incremented by the
+** current cache hit or miss count, according to the value of eStat. If the
+** reset parameter is non-zero, the cache hit or miss count is zeroed before
+** returning.
+*/
+SQLITE_PRIVATE void sqlite3PagerCacheStat(Pager *pPager, int eStat, int reset, u64 *pnVal){
+
+  assert( eStat==SQLITE_DBSTATUS_CACHE_HIT
+       || eStat==SQLITE_DBSTATUS_CACHE_MISS
+       || eStat==SQLITE_DBSTATUS_CACHE_WRITE
+       || eStat==SQLITE_DBSTATUS_CACHE_WRITE+1
+  );
+
+  assert( SQLITE_DBSTATUS_CACHE_HIT+1==SQLITE_DBSTATUS_CACHE_MISS );
+  assert( SQLITE_DBSTATUS_CACHE_HIT+2==SQLITE_DBSTATUS_CACHE_WRITE );
+  assert( PAGER_STAT_HIT==0 && PAGER_STAT_MISS==1
+           && PAGER_STAT_WRITE==2 && PAGER_STAT_SPILL==3 );
+
+  eStat -= SQLITE_DBSTATUS_CACHE_HIT;
+  *pnVal += pPager->aStat[eStat];
+  if( reset ){
+    pPager->aStat[eStat] = 0;
+  }
+}
+
+/*
+** Return true if this is an in-memory or temp-file backed pager.
+*/
+SQLITE_PRIVATE int sqlite3PagerIsMemdb(Pager *pPager){
+  return pPager->tempFile || pPager->memVfs;
+}
+
+/*
+** Check that there are at least nSavepoint savepoints open. If there are
+** currently less than nSavepoints open, then open one or more savepoints
+** to make up the difference. If the number of savepoints is already
+** equal to nSavepoint, then this function is a no-op.
+**
+** If a memory allocation fails, SQLITE_NOMEM is returned. If an error
+** occurs while opening the sub-journal file, then an IO error code is
+** returned. Otherwise, SQLITE_OK.
+*/
+static SQLITE_NOINLINE int pagerOpenSavepoint(Pager *pPager, int nSavepoint){
+  int rc = SQLITE_OK;                       /* Return code */
+  int nCurrent = pPager->nSavepoint;        /* Current number of savepoints */
+  int ii;                                   /* Iterator variable */
+  PagerSavepoint *aNew;                     /* New Pager.aSavepoint array */
+
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
+  assert( nSavepoint>nCurrent && pPager->useJournal );
+
+  /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
+  ** if the allocation fails. Otherwise, zero the new portion in case a
+  ** malloc failure occurs while populating it in the for(...) loop below.
+  */
+  aNew = (PagerSavepoint *)sqlite3Realloc(
+      pPager->aSavepoint, sizeof(PagerSavepoint)*nSavepoint
+  );
+  if( !aNew ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  memset(&aNew[nCurrent], 0, (nSavepoint-nCurrent) * sizeof(PagerSavepoint));
+  pPager->aSavepoint = aNew;
+
+  /* Populate the PagerSavepoint structures just allocated. */
+  for(ii=nCurrent; ii<nSavepoint; ii++){
+    aNew[ii].nOrig = pPager->dbSize;
+    if( isOpen(pPager->jfd) && pPager->journalOff>0 ){
+      aNew[ii].iOffset = pPager->journalOff;
+    }else{
+      aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
+    }
+    aNew[ii].iSubRec = pPager->nSubRec;
+    aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
+    aNew[ii].bTruncateOnRelease = 1;
+    if( !aNew[ii].pInSavepoint ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    if( pagerUseWal(pPager) ){
+      sqlite3WalSavepoint(pPager->pWal, aNew[ii].aWalData);
+    }
+    pPager->nSavepoint = ii+1;
+  }
+  assert( pPager->nSavepoint==nSavepoint );
+  assertTruncateConstraint(pPager);
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
+
+  if( nSavepoint>pPager->nSavepoint && pPager->useJournal ){
+    return pagerOpenSavepoint(pPager, nSavepoint);
+  }else{
+    return SQLITE_OK;
+  }
+}
+
+
+/*
+** This function is called to rollback or release (commit) a savepoint.
+** The savepoint to release or rollback need not be the most recently
+** created savepoint.
+**
+** Parameter op is always either SAVEPOINT_ROLLBACK or SAVEPOINT_RELEASE.
+** If it is SAVEPOINT_RELEASE, then release and destroy the savepoint with
+** index iSavepoint. If it is SAVEPOINT_ROLLBACK, then rollback all changes
+** that have occurred since the specified savepoint was created.
+**
+** The savepoint to rollback or release is identified by parameter
+** iSavepoint. A value of 0 means to operate on the outermost savepoint
+** (the first created). A value of (Pager.nSavepoint-1) means operate
+** on the most recently created savepoint. If iSavepoint is greater than
+** (Pager.nSavepoint-1), then this function is a no-op.
+**
+** If a negative value is passed to this function, then the current
+** transaction is rolled back. This is different to calling
+** sqlite3PagerRollback() because this function does not terminate
+** the transaction or unlock the database, it just restores the
+** contents of the database to its original state.
+**
+** In any case, all savepoints with an index greater than iSavepoint
+** are destroyed. If this is a release operation (op==SAVEPOINT_RELEASE),
+** then savepoint iSavepoint is also destroyed.
+**
+** This function may return SQLITE_NOMEM if a memory allocation fails,
+** or an IO error code if an IO error occurs while rolling back a
+** savepoint. If no errors occur, SQLITE_OK is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint){
+  int rc = pPager->errCode;
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+  if( op==SAVEPOINT_RELEASE ) rc = SQLITE_OK;
+#endif
+
+  assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
+  assert( iSavepoint>=0 || op==SAVEPOINT_ROLLBACK );
+
+  if( rc==SQLITE_OK && iSavepoint<pPager->nSavepoint ){
+    int ii;            /* Iterator variable */
+    int nNew;          /* Number of remaining savepoints after this op. */
+
+    /* Figure out how many savepoints will still be active after this
+    ** operation. Store this value in nNew. Then free resources associated
+    ** with any savepoints that are destroyed by this operation.
+    */
+    nNew = iSavepoint + (( op==SAVEPOINT_RELEASE ) ? 0 : 1);
+    for(ii=nNew; ii<pPager->nSavepoint; ii++){
+      sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
+    }
+    pPager->nSavepoint = nNew;
+
+    /* Truncate the sub-journal so that it only includes the parts
+    ** that are still in use. */
+    if( op==SAVEPOINT_RELEASE ){
+      PagerSavepoint *pRel = &pPager->aSavepoint[nNew];
+      if( pRel->bTruncateOnRelease && isOpen(pPager->sjfd) ){
+        /* Only truncate if it is an in-memory sub-journal. */
+        if( sqlite3JournalIsInMemory(pPager->sjfd) ){
+          i64 sz = (pPager->pageSize+4)*(i64)pRel->iSubRec;
+          rc = sqlite3OsTruncate(pPager->sjfd, sz);
+          assert( rc==SQLITE_OK );
+        }
+        pPager->nSubRec = pRel->iSubRec;
+      }
+    }
+    /* Else this is a rollback operation, playback the specified savepoint.
+    ** If this is a temp-file, it is possible that the journal file has
+    ** not yet been opened. In this case there have been no changes to
+    ** the database file, so the playback operation can be skipped.
+    */
+    else if( pagerUseWal(pPager) || isOpen(pPager->jfd) ){
+      PagerSavepoint *pSavepoint = (nNew==0)?0:&pPager->aSavepoint[nNew-1];
+      rc = pagerPlaybackSavepoint(pPager, pSavepoint);
+      assert(rc!=SQLITE_DONE);
+    }
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+    /* If the cache has been modified but the savepoint cannot be rolled
+    ** back journal_mode=off, put the pager in the error state. This way,
+    ** if the VFS used by this pager includes ZipVFS, the entire transaction
+    ** can be rolled back at the ZipVFS level.  */
+    else if(
+        pPager->journalMode==PAGER_JOURNALMODE_OFF
+     && pPager->eState>=PAGER_WRITER_CACHEMOD
+    ){
+      pPager->errCode = SQLITE_ABORT;
+      pPager->eState = PAGER_ERROR;
+      setGetterMethod(pPager);
+    }
+#endif
+  }
+
+  return rc;
+}
+
+/*
+** Return the full pathname of the database file.
+**
+** Except, if the pager is in-memory only, then return an empty string if
+** nullIfMemDb is true.  This routine is called with nullIfMemDb==1 when
+** used to report the filename to the user, for compatibility with legacy
+** behavior.  But when the Btree needs to know the filename for matching to
+** shared cache, it uses nullIfMemDb==0 so that in-memory databases can
+** participate in shared-cache.
+**
+** The return value to this routine is always safe to use with
+** sqlite3_uri_parameter() and sqlite3_filename_database() and friends.
+*/
+SQLITE_PRIVATE const char *sqlite3PagerFilename(const Pager *pPager, int nullIfMemDb){
+  static const char zFake[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
+  if( nullIfMemDb && (pPager->memDb || sqlite3IsMemdb(pPager->pVfs)) ){
+    return &zFake[4];
+  }else{
+    return pPager->zFilename;
+  }
+}
+
+/*
+** Return the VFS structure for the pager.
+*/
+SQLITE_PRIVATE sqlite3_vfs *sqlite3PagerVfs(Pager *pPager){
+  return pPager->pVfs;
+}
+
+/*
+** Return the file handle for the database file associated
+** with the pager.  This might return NULL if the file has
+** not yet been opened.
+*/
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerFile(Pager *pPager){
+  return pPager->fd;
+}
+
+/*
+** Return the file handle for the journal file (if it exists).
+** This will be either the rollback journal or the WAL file.
+*/
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerJrnlFile(Pager *pPager){
+#ifdef SQLITE_OMIT_WAL
+  return pPager->jfd;
+#else
+  return pPager->pWal ? sqlite3WalFile(pPager->pWal) : pPager->jfd;
+#endif
+}
+
+/*
+** Return the full pathname of the journal file.
+*/
+SQLITE_PRIVATE const char *sqlite3PagerJournalname(Pager *pPager){
+  return pPager->zJournal;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Move the page pPg to location pgno in the file.
+**
+** There must be no references to the page previously located at
+** pgno (which we call pPgOld) though that page is allowed to be
+** in cache.  If the page previously located at pgno is not already
+** in the rollback journal, it is not put there by by this routine.
+**
+** References to the page pPg remain valid. Updating any
+** meta-data associated with pPg (i.e. data stored in the nExtra bytes
+** allocated along with the page) is the responsibility of the caller.
+**
+** A transaction must be active when this routine is called. It used to be
+** required that a statement transaction was not active, but this restriction
+** has been removed (CREATE INDEX needs to move a page when a statement
+** transaction is active).
+**
+** If the fourth argument, isCommit, is non-zero, then this page is being
+** moved as part of a database reorganization just before the transaction
+** is being committed. In this case, it is guaranteed that the database page
+** pPg refers to will not be written to again within this transaction.
+**
+** This function may return SQLITE_NOMEM or an IO error code if an error
+** occurs. Otherwise, it returns SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
+  PgHdr *pPgOld;               /* The page being overwritten. */
+  Pgno needSyncPgno = 0;       /* Old value of pPg->pgno, if sync is required */
+  int rc;                      /* Return code */
+  Pgno origPgno;               /* The original page number */
+
+  assert( pPg->nRef>0 );
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* In order to be able to rollback, an in-memory database must journal
+  ** the page we are moving from.
+  */
+  assert( pPager->tempFile || !MEMDB );
+  if( pPager->tempFile ){
+    rc = sqlite3PagerWrite(pPg);
+    if( rc ) return rc;
+  }
+
+  /* If the page being moved is dirty and has not been saved by the latest
+  ** savepoint, then save the current contents of the page into the
+  ** sub-journal now. This is required to handle the following scenario:
+  **
+  **   BEGIN;
+  **     <journal page X, then modify it in memory>
+  **     SAVEPOINT one;
+  **       <Move page X to location Y>
+  **     ROLLBACK TO one;
+  **
+  ** If page X were not written to the sub-journal here, it would not
+  ** be possible to restore its contents when the "ROLLBACK TO one"
+  ** statement were is processed.
+  **
+  ** subjournalPage() may need to allocate space to store pPg->pgno into
+  ** one or more savepoint bitvecs. This is the reason this function
+  ** may return SQLITE_NOMEM.
+  */
+  if( (pPg->flags & PGHDR_DIRTY)!=0
+   && SQLITE_OK!=(rc = subjournalPageIfRequired(pPg))
+  ){
+    return rc;
+  }
+
+  PAGERTRACE(("MOVE %d page %d (needSync=%d) moves to %d\n",
+      PAGERID(pPager), pPg->pgno, (pPg->flags&PGHDR_NEED_SYNC)?1:0, pgno));
+  IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
+
+  /* If the journal needs to be sync()ed before page pPg->pgno can
+  ** be written to, store pPg->pgno in local variable needSyncPgno.
+  **
+  ** If the isCommit flag is set, there is no need to remember that
+  ** the journal needs to be sync()ed before database page pPg->pgno
+  ** can be written to. The caller has already promised not to write to it.
+  */
+  if( (pPg->flags&PGHDR_NEED_SYNC) && !isCommit ){
+    needSyncPgno = pPg->pgno;
+    assert( pPager->journalMode==PAGER_JOURNALMODE_OFF ||
+            pageInJournal(pPager, pPg) || pPg->pgno>pPager->dbOrigSize );
+    assert( pPg->flags&PGHDR_DIRTY );
+  }
+
+  /* If the cache contains a page with page-number pgno, remove it
+  ** from its hash chain. Also, if the PGHDR_NEED_SYNC flag was set for
+  ** page pgno before the 'move' operation, it needs to be retained
+  ** for the page moved there.
+  */
+  pPg->flags &= ~PGHDR_NEED_SYNC;
+  pPgOld = sqlite3PagerLookup(pPager, pgno);
+  assert( !pPgOld || pPgOld->nRef==1 || CORRUPT_DB );
+  if( pPgOld ){
+    if( NEVER(pPgOld->nRef>1) ){
+      sqlite3PagerUnrefNotNull(pPgOld);
+      return SQLITE_CORRUPT_BKPT;
+    }
+    pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
+    if( pPager->tempFile ){
+      /* Do not discard pages from an in-memory database since we might
+      ** need to rollback later.  Just move the page out of the way. */
+      sqlite3PcacheMove(pPgOld, pPager->dbSize+1);
+    }else{
+      sqlite3PcacheDrop(pPgOld);
+    }
+  }
+
+  origPgno = pPg->pgno;
+  sqlite3PcacheMove(pPg, pgno);
+  sqlite3PcacheMakeDirty(pPg);
+
+  /* For an in-memory database, make sure the original page continues
+  ** to exist, in case the transaction needs to roll back.  Use pPgOld
+  ** as the original page since it has already been allocated.
+  */
+  if( pPager->tempFile && pPgOld ){
+    sqlite3PcacheMove(pPgOld, origPgno);
+    sqlite3PagerUnrefNotNull(pPgOld);
+  }
+
+  if( needSyncPgno ){
+    /* If needSyncPgno is non-zero, then the journal file needs to be
+    ** sync()ed before any data is written to database file page needSyncPgno.
+    ** Currently, no such page exists in the page-cache and the
+    ** "is journaled" bitvec flag has been set. This needs to be remedied by
+    ** loading the page into the pager-cache and setting the PGHDR_NEED_SYNC
+    ** flag.
+    **
+    ** If the attempt to load the page into the page-cache fails, (due
+    ** to a malloc() or IO failure), clear the bit in the pInJournal[]
+    ** array. Otherwise, if the page is loaded and written again in
+    ** this transaction, it may be written to the database file before
+    ** it is synced into the journal file. This way, it may end up in
+    ** the journal file twice, but that is not a problem.
+    */
+    PgHdr *pPgHdr;
+    rc = sqlite3PagerGet(pPager, needSyncPgno, &pPgHdr, 0);
+    if( rc!=SQLITE_OK ){
+      if( needSyncPgno<=pPager->dbOrigSize ){
+        assert( pPager->pTmpSpace!=0 );
+        sqlite3BitvecClear(pPager->pInJournal, needSyncPgno, pPager->pTmpSpace);
+      }
+      return rc;
+    }
+    pPgHdr->flags |= PGHDR_NEED_SYNC;
+    sqlite3PcacheMakeDirty(pPgHdr);
+    sqlite3PagerUnrefNotNull(pPgHdr);
+  }
+
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** The page handle passed as the first argument refers to a dirty page
+** with a page number other than iNew. This function changes the page's
+** page number to iNew and sets the value of the PgHdr.flags field to
+** the value passed as the third parameter.
+*/
+SQLITE_PRIVATE void sqlite3PagerRekey(DbPage *pPg, Pgno iNew, u16 flags){
+  assert( pPg->pgno!=iNew );
+  pPg->flags = flags;
+  sqlite3PcacheMove(pPg, iNew);
+}
+
+/*
+** Return a pointer to the data for the specified page.
+*/
+SQLITE_PRIVATE void *sqlite3PagerGetData(DbPage *pPg){
+  assert( pPg->nRef>0 || pPg->pPager->memDb );
+  return pPg->pData;
+}
+
+/*
+** Return a pointer to the Pager.nExtra bytes of "extra" space
+** allocated along with the specified page.
+*/
+SQLITE_PRIVATE void *sqlite3PagerGetExtra(DbPage *pPg){
+  return pPg->pExtra;
+}
+
+/*
+** Get/set the locking-mode for this pager. Parameter eMode must be one
+** of PAGER_LOCKINGMODE_QUERY, PAGER_LOCKINGMODE_NORMAL or
+** PAGER_LOCKINGMODE_EXCLUSIVE. If the parameter is not _QUERY, then
+** the locking-mode is set to the value specified.
+**
+** The returned value is either PAGER_LOCKINGMODE_NORMAL or
+** PAGER_LOCKINGMODE_EXCLUSIVE, indicating the current (possibly updated)
+** locking-mode.
+*/
+SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *pPager, int eMode){
+  assert( eMode==PAGER_LOCKINGMODE_QUERY
+            || eMode==PAGER_LOCKINGMODE_NORMAL
+            || eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
+  assert( PAGER_LOCKINGMODE_QUERY<0 );
+  assert( PAGER_LOCKINGMODE_NORMAL>=0 && PAGER_LOCKINGMODE_EXCLUSIVE>=0 );
+  assert( pPager->exclusiveMode || 0==sqlite3WalHeapMemory(pPager->pWal) );
+  if( eMode>=0 && !pPager->tempFile && !sqlite3WalHeapMemory(pPager->pWal) ){
+    pPager->exclusiveMode = (u8)eMode;
+  }
+  return (int)pPager->exclusiveMode;
+}
+
+/*
+** Set the journal-mode for this pager. Parameter eMode must be one of:
+**
+**    PAGER_JOURNALMODE_DELETE
+**    PAGER_JOURNALMODE_TRUNCATE
+**    PAGER_JOURNALMODE_PERSIST
+**    PAGER_JOURNALMODE_OFF
+**    PAGER_JOURNALMODE_MEMORY
+**    PAGER_JOURNALMODE_WAL
+**
+** The journalmode is set to the value specified if the change is allowed.
+** The change may be disallowed for the following reasons:
+**
+**   *  An in-memory database can only have its journal_mode set to _OFF
+**      or _MEMORY.
+**
+**   *  Temporary databases cannot have _WAL journalmode.
+**
+** The returned indicate the current (possibly updated) journal-mode.
+*/
+SQLITE_PRIVATE int sqlite3PagerSetJournalMode(Pager *pPager, int eMode){
+  u8 eOld = pPager->journalMode;    /* Prior journalmode */
+
+  /* The eMode parameter is always valid */
+  assert(      eMode==PAGER_JOURNALMODE_DELETE    /* 0 */
+            || eMode==PAGER_JOURNALMODE_PERSIST   /* 1 */
+            || eMode==PAGER_JOURNALMODE_OFF       /* 2 */
+            || eMode==PAGER_JOURNALMODE_TRUNCATE  /* 3 */
+            || eMode==PAGER_JOURNALMODE_MEMORY    /* 4 */
+            || eMode==PAGER_JOURNALMODE_WAL       /* 5 */ );
+
+  /* This routine is only called from the OP_JournalMode opcode, and
+  ** the logic there will never allow a temporary file to be changed
+  ** to WAL mode.
+  */
+  assert( pPager->tempFile==0 || eMode!=PAGER_JOURNALMODE_WAL );
+
+  /* Do allow the journalmode of an in-memory database to be set to
+  ** anything other than MEMORY or OFF
+  */
+  if( MEMDB ){
+    assert( eOld==PAGER_JOURNALMODE_MEMORY || eOld==PAGER_JOURNALMODE_OFF );
+    if( eMode!=PAGER_JOURNALMODE_MEMORY && eMode!=PAGER_JOURNALMODE_OFF ){
+      eMode = eOld;
+    }
+  }
+
+  if( eMode!=eOld ){
+
+    /* Change the journal mode. */
+    assert( pPager->eState!=PAGER_ERROR );
+    pPager->journalMode = (u8)eMode;
+
+    /* When transitioning from TRUNCATE or PERSIST to any other journal
+    ** mode except WAL, unless the pager is in locking_mode=exclusive mode,
+    ** delete the journal file.
+    */
+    assert( (PAGER_JOURNALMODE_TRUNCATE & 5)==1 );
+    assert( (PAGER_JOURNALMODE_PERSIST & 5)==1 );
+    assert( (PAGER_JOURNALMODE_DELETE & 5)==0 );
+    assert( (PAGER_JOURNALMODE_MEMORY & 5)==4 );
+    assert( (PAGER_JOURNALMODE_OFF & 5)==0 );
+    assert( (PAGER_JOURNALMODE_WAL & 5)==5 );
+
+    assert( isOpen(pPager->fd) || pPager->exclusiveMode );
+    if( !pPager->exclusiveMode && (eOld & 5)==1 && (eMode & 1)==0 ){
+      /* In this case we would like to delete the journal file. If it is
+      ** not possible, then that is not a problem. Deleting the journal file
+      ** here is an optimization only.
+      **
+      ** Before deleting the journal file, obtain a RESERVED lock on the
+      ** database file. This ensures that the journal file is not deleted
+      ** while it is in use by some other client.
+      */
+      sqlite3OsClose(pPager->jfd);
+      if( pPager->eLock>=RESERVED_LOCK ){
+        sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
+      }else{
+        int rc = SQLITE_OK;
+        int state = pPager->eState;
+        assert( state==PAGER_OPEN || state==PAGER_READER );
+        if( state==PAGER_OPEN ){
+          rc = sqlite3PagerSharedLock(pPager);
+        }
+        if( pPager->eState==PAGER_READER ){
+          assert( rc==SQLITE_OK );
+          rc = pagerLockDb(pPager, RESERVED_LOCK);
+        }
+        if( rc==SQLITE_OK ){
+          sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
+        }
+        if( rc==SQLITE_OK && state==PAGER_READER ){
+          pagerUnlockDb(pPager, SHARED_LOCK);
+        }else if( state==PAGER_OPEN ){
+          pager_unlock(pPager);
+        }
+        assert( state==pPager->eState );
+      }
+    }else if( eMode==PAGER_JOURNALMODE_OFF || eMode==PAGER_JOURNALMODE_MEMORY ){
+      sqlite3OsClose(pPager->jfd);
+    }
+  }
+
+  /* Return the new journal mode */
+  return (int)pPager->journalMode;
+}
+
+/*
+** Return the current journal mode.
+*/
+SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager *pPager){
+  return (int)pPager->journalMode;
+}
+
+/*
+** Return TRUE if the pager is in a state where it is OK to change the
+** journalmode.  Journalmode changes can only happen when the database
+** is unmodified.
+*/
+SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager *pPager){
+  assert( assert_pager_state(pPager) );
+  if( pPager->eState>=PAGER_WRITER_CACHEMOD ) return 0;
+  if( NEVER(isOpen(pPager->jfd) && pPager->journalOff>0) ) return 0;
+  return 1;
+}
+
+/*
+** Get/set the size-limit used for persistent journal files.
+**
+** Setting the size limit to -1 means no limit is enforced.
+** An attempt to set a limit smaller than -1 is a no-op.
+*/
+SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *pPager, i64 iLimit){
+  if( iLimit>=-1 ){
+    pPager->journalSizeLimit = iLimit;
+    sqlite3WalLimit(pPager->pWal, iLimit);
+  }
+  return pPager->journalSizeLimit;
+}
+
+/*
+** Return a pointer to the pPager->pBackup variable. The backup module
+** in backup.c maintains the content of this variable. This module
+** uses it opaquely as an argument to sqlite3BackupRestart() and
+** sqlite3BackupUpdate() only.
+*/
+SQLITE_PRIVATE sqlite3_backup **sqlite3PagerBackupPtr(Pager *pPager){
+  return &pPager->pBackup;
+}
+
+#ifndef SQLITE_OMIT_VACUUM
+/*
+** Unless this is an in-memory or temporary database, clear the pager cache.
+*/
+SQLITE_PRIVATE void sqlite3PagerClearCache(Pager *pPager){
+  assert( MEMDB==0 || pPager->tempFile );
+  if( pPager->tempFile==0 ) pager_reset(pPager);
+}
+#endif
+
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** This function is called when the user invokes "PRAGMA wal_checkpoint",
+** "PRAGMA wal_blocking_checkpoint" or calls the sqlite3_wal_checkpoint()
+** or wal_blocking_checkpoint() API functions.
+**
+** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
+*/
+SQLITE_PRIVATE int sqlite3PagerCheckpoint(
+  Pager *pPager,                  /* Checkpoint on this pager */
+  sqlite3 *db,                    /* Db handle used to check for interrupts */
+  int eMode,                      /* Type of checkpoint */
+  int *pnLog,                     /* OUT: Final number of frames in log */
+  int *pnCkpt                     /* OUT: Final number of checkpointed frames */
+){
+  int rc = SQLITE_OK;
+  if( pPager->pWal==0 && pPager->journalMode==PAGER_JOURNALMODE_WAL ){
+    /* This only happens when a database file is zero bytes in size opened and
+    ** then "PRAGMA journal_mode=WAL" is run and then sqlite3_wal_checkpoint()
+    ** is invoked without any intervening transactions.  We need to start
+    ** a transaction to initialize pWal.  The PRAGMA table_list statement is
+    ** used for this since it starts transactions on every database file,
+    ** including all ATTACHed databases.  This seems expensive for a single
+    ** sqlite3_wal_checkpoint() call, but it happens very rarely.
+    ** https://sqlite.org/forum/forumpost/fd0f19d229156939
+    */
+    sqlite3_exec(db, "PRAGMA table_list",0,0,0);
+  }
+  if( pPager->pWal ){
+    rc = sqlite3WalCheckpoint(pPager->pWal, db, eMode,
+        (eMode==SQLITE_CHECKPOINT_PASSIVE ? 0 : pPager->xBusyHandler),
+        pPager->pBusyHandlerArg,
+        pPager->walSyncFlags, pPager->pageSize, (u8 *)pPager->pTmpSpace,
+        pnLog, pnCkpt
+    );
+  }
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3PagerWalCallback(Pager *pPager){
+  return sqlite3WalCallback(pPager->pWal);
+}
+
+/*
+** Return true if the underlying VFS for the given pager supports the
+** primitives necessary for write-ahead logging.
+*/
+SQLITE_PRIVATE int sqlite3PagerWalSupported(Pager *pPager){
+  const sqlite3_io_methods *pMethods = pPager->fd->pMethods;
+  if( pPager->noLock ) return 0;
+  return pPager->exclusiveMode || (pMethods->iVersion>=2 && pMethods->xShmMap);
+}
+
+/*
+** Attempt to take an exclusive lock on the database file. If a PENDING lock
+** is obtained instead, immediately release it.
+*/
+static int pagerExclusiveLock(Pager *pPager){
+  int rc;                         /* Return code */
+  u8 eOrigLock;                   /* Original lock */
+
+  assert( pPager->eLock>=SHARED_LOCK );
+  eOrigLock = pPager->eLock;
+  rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
+  if( rc!=SQLITE_OK ){
+    /* If the attempt to grab the exclusive lock failed, release the
+    ** pending lock that may have been obtained instead.  */
+    pagerUnlockDb(pPager, eOrigLock);
+  }
+
+  return rc;
+}
+
+/*
+** Call sqlite3WalOpen() to open the WAL handle. If the pager is in
+** exclusive-locking mode when this function is called, take an EXCLUSIVE
+** lock on the database file and use heap-memory to store the wal-index
+** in. Otherwise, use the normal shared-memory.
+*/
+static int pagerOpenWal(Pager *pPager){
+  int rc = SQLITE_OK;
+
+  assert( pPager->pWal==0 && pPager->tempFile==0 );
+  assert( pPager->eLock==SHARED_LOCK || pPager->eLock==EXCLUSIVE_LOCK );
+
+  /* If the pager is already in exclusive-mode, the WAL module will use
+  ** heap-memory for the wal-index instead of the VFS shared-memory
+  ** implementation. Take the exclusive lock now, before opening the WAL
+  ** file, to make sure this is safe.
+  */
+  if( pPager->exclusiveMode ){
+    rc = pagerExclusiveLock(pPager);
+  }
+
+  /* Open the connection to the log file. If this operation fails,
+  ** (e.g. due to malloc() failure), return an error code.
+  */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3WalOpen(pPager->pVfs,
+        pPager->fd, pPager->zWal, pPager->exclusiveMode,
+        pPager->journalSizeLimit, &pPager->pWal
+    );
+  }
+  pagerFixMaplimit(pPager);
+
+  return rc;
+}
+
+
+/*
+** The caller must be holding a SHARED lock on the database file to call
+** this function.
+**
+** If the pager passed as the first argument is open on a real database
+** file (not a temp file or an in-memory database), and the WAL file
+** is not already open, make an attempt to open it now. If successful,
+** return SQLITE_OK. If an error occurs or the VFS used by the pager does
+** not support the xShmXXX() methods, return an error code. *pbOpen is
+** not modified in either case.
+**
+** If the pager is open on a temp-file (or in-memory database), or if
+** the WAL file is already open, set *pbOpen to 1 and return SQLITE_OK
+** without doing anything.
+*/
+SQLITE_PRIVATE int sqlite3PagerOpenWal(
+  Pager *pPager,                  /* Pager object */
+  int *pbOpen                     /* OUT: Set to true if call is a no-op */
+){
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( assert_pager_state(pPager) );
+  assert( pPager->eState==PAGER_OPEN   || pbOpen );
+  assert( pPager->eState==PAGER_READER || !pbOpen );
+  assert( pbOpen==0 || *pbOpen==0 );
+  assert( pbOpen!=0 || (!pPager->tempFile && !pPager->pWal) );
+
+  if( !pPager->tempFile && !pPager->pWal ){
+    if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;
+
+    /* Close any rollback journal previously open */
+    sqlite3OsClose(pPager->jfd);
+
+    rc = pagerOpenWal(pPager);
+    if( rc==SQLITE_OK ){
+      pPager->journalMode = PAGER_JOURNALMODE_WAL;
+      pPager->eState = PAGER_OPEN;
+    }
+  }else{
+    *pbOpen = 1;
+  }
+
+  return rc;
+}
+
+/*
+** This function is called to close the connection to the log file prior
+** to switching from WAL to rollback mode.
+**
+** Before closing the log file, this function attempts to take an
+** EXCLUSIVE lock on the database file. If this cannot be obtained, an
+** error (SQLITE_BUSY) is returned and the log connection is not closed.
+** If successful, the EXCLUSIVE lock is not released before returning.
+*/
+SQLITE_PRIVATE int sqlite3PagerCloseWal(Pager *pPager, sqlite3 *db){
+  int rc = SQLITE_OK;
+
+  assert( pPager->journalMode==PAGER_JOURNALMODE_WAL );
+
+  /* If the log file is not already open, but does exist in the file-system,
+  ** it may need to be checkpointed before the connection can switch to
+  ** rollback mode. Open it now so this can happen.
+  */
+  if( !pPager->pWal ){
+    int logexists = 0;
+    rc = pagerLockDb(pPager, SHARED_LOCK);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3OsAccess(
+          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &logexists
+      );
+    }
+    if( rc==SQLITE_OK && logexists ){
+      rc = pagerOpenWal(pPager);
+    }
+  }
+
+  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
+  ** the database file, the log and log-summary files will be deleted.
+  */
+  if( rc==SQLITE_OK && pPager->pWal ){
+    rc = pagerExclusiveLock(pPager);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3WalClose(pPager->pWal, db, pPager->walSyncFlags,
+                           pPager->pageSize, (u8*)pPager->pTmpSpace);
+      pPager->pWal = 0;
+      pagerFixMaplimit(pPager);
+      if( rc && !pPager->exclusiveMode ) pagerUnlockDb(pPager, SHARED_LOCK);
+    }
+  }
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+/*
+** If pager pPager is a wal-mode database not in exclusive locking mode,
+** invoke the sqlite3WalWriteLock() function on the associated Wal object
+** with the same db and bLock parameters as were passed to this function.
+** Return an SQLite error code if an error occurs, or SQLITE_OK otherwise.
+*/
+SQLITE_PRIVATE int sqlite3PagerWalWriteLock(Pager *pPager, int bLock){
+  int rc = SQLITE_OK;
+  if( pagerUseWal(pPager) && pPager->exclusiveMode==0 ){
+    rc = sqlite3WalWriteLock(pPager->pWal, bLock);
+  }
+  return rc;
+}
+
+/*
+** Set the database handle used by the wal layer to determine if
+** blocking locks are required.
+*/
+SQLITE_PRIVATE void sqlite3PagerWalDb(Pager *pPager, sqlite3 *db){
+  if( pagerUseWal(pPager) ){
+    sqlite3WalDb(pPager->pWal, db);
+  }
+}
+#endif
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+/*
+** If this is a WAL database, obtain a snapshot handle for the snapshot
+** currently open. Otherwise, return an error.
+*/
+SQLITE_PRIVATE int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot){
+  int rc = SQLITE_ERROR;
+  if( pPager->pWal ){
+    rc = sqlite3WalSnapshotGet(pPager->pWal, ppSnapshot);
+  }
+  return rc;
+}
+
+/*
+** If this is a WAL database, store a pointer to pSnapshot. Next time a
+** read transaction is opened, attempt to read from the snapshot it
+** identifies. If this is not a WAL database, return an error.
+*/
+SQLITE_PRIVATE int sqlite3PagerSnapshotOpen(
+  Pager *pPager,
+  sqlite3_snapshot *pSnapshot
+){
+  int rc = SQLITE_OK;
+  if( pPager->pWal ){
+    sqlite3WalSnapshotOpen(pPager->pWal, pSnapshot);
+  }else{
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** If this is a WAL database, call sqlite3WalSnapshotRecover(). If this
+** is not a WAL database, return an error.
+*/
+SQLITE_PRIVATE int sqlite3PagerSnapshotRecover(Pager *pPager){
+  int rc;
+  if( pPager->pWal ){
+    rc = sqlite3WalSnapshotRecover(pPager->pWal);
+  }else{
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** The caller currently has a read transaction open on the database.
+** If this is not a WAL database, SQLITE_ERROR is returned. Otherwise,
+** this function takes a SHARED lock on the CHECKPOINTER slot and then
+** checks if the snapshot passed as the second argument is still
+** available. If so, SQLITE_OK is returned.
+**
+** If the snapshot is not available, SQLITE_ERROR is returned. Or, if
+** the CHECKPOINTER lock cannot be obtained, SQLITE_BUSY. If any error
+** occurs (any value other than SQLITE_OK is returned), the CHECKPOINTER
+** lock is released before returning.
+*/
+SQLITE_PRIVATE int sqlite3PagerSnapshotCheck(Pager *pPager, sqlite3_snapshot *pSnapshot){
+  int rc;
+  if( pPager->pWal ){
+    rc = sqlite3WalSnapshotCheck(pPager->pWal, pSnapshot);
+  }else{
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** Release a lock obtained by an earlier successful call to
+** sqlite3PagerSnapshotCheck().
+*/
+SQLITE_PRIVATE void sqlite3PagerSnapshotUnlock(Pager *pPager){
+  assert( pPager->pWal );
+  sqlite3WalSnapshotUnlock(pPager->pWal);
+}
+
+#endif /* SQLITE_ENABLE_SNAPSHOT */
+#endif /* !SQLITE_OMIT_WAL */
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/*
+** A read-lock must be held on the pager when this function is called. If
+** the pager is in WAL mode and the WAL file currently contains one or more
+** frames, return the size in bytes of the page images stored within the
+** WAL frames. Otherwise, if this is not a WAL database or the WAL file
+** is empty, return 0.
+*/
+SQLITE_PRIVATE int sqlite3PagerWalFramesize(Pager *pPager){
+  assert( pPager->eState>=PAGER_READER );
+  return sqlite3WalFramesize(pPager->pWal);
+}
+#endif
+
+#if defined(SQLITE_USE_SEH) && !defined(SQLITE_OMIT_WAL)
+SQLITE_PRIVATE int sqlite3PagerWalSystemErrno(Pager *pPager){
+  return sqlite3WalSystemErrno(pPager->pWal);
+}
+#endif
+
+#endif /* SQLITE_OMIT_DISKIO */
+
+/************** End of pager.c ***********************************************/
+/************** Begin file wal.c *********************************************/
+/*
+** 2010 February 1
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the implementation of a write-ahead log (WAL) used in
+** "journal_mode=WAL" mode.
+**
+** WRITE-AHEAD LOG (WAL) FILE FORMAT
+**
+** A WAL file consists of a header followed by zero or more "frames".
+** Each frame records the revised content of a single page from the
+** database file.  All changes to the database are recorded by writing
+** frames into the WAL.  Transactions commit when a frame is written that
+** contains a commit marker.  A single WAL can and usually does record
+** multiple transactions.  Periodically, the content of the WAL is
+** transferred back into the database file in an operation called a
+** "checkpoint".
+**
+** A single WAL file can be used multiple times.  In other words, the
+** WAL can fill up with frames and then be checkpointed and then new
+** frames can overwrite the old ones.  A WAL always grows from beginning
+** toward the end.  Checksums and counters attached to each frame are
+** used to determine which frames within the WAL are valid and which
+** are leftovers from prior checkpoints.
+**
+** The WAL header is 32 bytes in size and consists of the following eight
+** big-endian 32-bit unsigned integer values:
+**
+**     0: Magic number.  0x377f0682 or 0x377f0683
+**     4: File format version.  Currently 3007000
+**     8: Database page size.  Example: 1024
+**    12: Checkpoint sequence number
+**    16: Salt-1, random integer incremented with each checkpoint
+**    20: Salt-2, a different random integer changing with each ckpt
+**    24: Checksum-1 (first part of checksum for first 24 bytes of header).
+**    28: Checksum-2 (second part of checksum for first 24 bytes of header).
+**
+** Immediately following the wal-header are zero or more frames. Each
+** frame consists of a 24-byte frame-header followed by <page-size> bytes
+** of page data. The frame-header is six big-endian 32-bit unsigned
+** integer values, as follows:
+**
+**     0: Page number.
+**     4: For commit records, the size of the database image in pages
+**        after the commit. For all other records, zero.
+**     8: Salt-1 (copied from the header)
+**    12: Salt-2 (copied from the header)
+**    16: Checksum-1.
+**    20: Checksum-2.
+**
+** A frame is considered valid if and only if the following conditions are
+** true:
+**
+**    (1) The salt-1 and salt-2 values in the frame-header match
+**        salt values in the wal-header
+**
+**    (2) The checksum values in the final 8 bytes of the frame-header
+**        exactly match the checksum computed consecutively on the
+**        WAL header and the first 8 bytes and the content of all frames
+**        up to and including the current frame.
+**
+** The checksum is computed using 32-bit big-endian integers if the
+** magic number in the first 4 bytes of the WAL is 0x377f0683 and it
+** is computed using little-endian if the magic number is 0x377f0682.
+** The checksum values are always stored in the frame header in a
+** big-endian format regardless of which byte order is used to compute
+** the checksum.  The checksum is computed by interpreting the input as
+** an even number of unsigned 32-bit integers: x[0] through x[N].  The
+** algorithm used for the checksum is as follows:
+**
+**   for i from 0 to n-1 step 2:
+**     s0 += x[i] + s1;
+**     s1 += x[i+1] + s0;
+**   endfor
+**
+** Note that s0 and s1 are both weighted checksums using fibonacci weights
+** in reverse order (the largest fibonacci weight occurs on the first element
+** of the sequence being summed.)  The s1 value spans all 32-bit
+** terms of the sequence whereas s0 omits the final term.
+**
+** On a checkpoint, the WAL is first VFS.xSync-ed, then valid content of the
+** WAL is transferred into the database, then the database is VFS.xSync-ed.
+** The VFS.xSync operations serve as write barriers - all writes launched
+** before the xSync must complete before any write that launches after the
+** xSync begins.
+**
+** After each checkpoint, the salt-1 value is incremented and the salt-2
+** value is randomized.  This prevents old and new frames in the WAL from
+** being considered valid at the same time and being checkpointing together
+** following a crash.
+**
+** READER ALGORITHM
+**
+** To read a page from the database (call it page number P), a reader
+** first checks the WAL to see if it contains page P.  If so, then the
+** last valid instance of page P that is a followed by a commit frame
+** or is a commit frame itself becomes the value read.  If the WAL
+** contains no copies of page P that are valid and which are a commit
+** frame or are followed by a commit frame, then page P is read from
+** the database file.
+**
+** To start a read transaction, the reader records the index of the last
+** valid frame in the WAL.  The reader uses this recorded "mxFrame" value
+** for all subsequent read operations.  New transactions can be appended
+** to the WAL, but as long as the reader uses its original mxFrame value
+** and ignores the newly appended content, it will see a consistent snapshot
+** of the database from a single point in time.  This technique allows
+** multiple concurrent readers to view different versions of the database
+** content simultaneously.
+**
+** The reader algorithm in the previous paragraphs works correctly, but
+** because frames for page P can appear anywhere within the WAL, the
+** reader has to scan the entire WAL looking for page P frames.  If the
+** WAL is large (multiple megabytes is typical) that scan can be slow,
+** and read performance suffers.  To overcome this problem, a separate
+** data structure called the wal-index is maintained to expedite the
+** search for frames of a particular page.
+**
+** WAL-INDEX FORMAT
+**
+** Conceptually, the wal-index is shared memory, though VFS implementations
+** might choose to implement the wal-index using a mmapped file.  Because
+** the wal-index is shared memory, SQLite does not support journal_mode=WAL
+** on a network filesystem.  All users of the database must be able to
+** share memory.
+**
+** In the default unix and windows implementation, the wal-index is a mmapped
+** file whose name is the database name with a "-shm" suffix added.  For that
+** reason, the wal-index is sometimes called the "shm" file.
+**
+** The wal-index is transient.  After a crash, the wal-index can (and should
+** be) reconstructed from the original WAL file.  In fact, the VFS is required
+** to either truncate or zero the header of the wal-index when the last
+** connection to it closes.  Because the wal-index is transient, it can
+** use an architecture-specific format; it does not have to be cross-platform.
+** Hence, unlike the database and WAL file formats which store all values
+** as big endian, the wal-index can store multi-byte values in the native
+** byte order of the host computer.
+**
+** The purpose of the wal-index is to answer this question quickly:  Given
+** a page number P and a maximum frame index M, return the index of the
+** last frame in the wal before frame M for page P in the WAL, or return
+** NULL if there are no frames for page P in the WAL prior to M.
+**
+** The wal-index consists of a header region, followed by an one or
+** more index blocks.
+**
+** The wal-index header contains the total number of frames within the WAL
+** in the mxFrame field.
+**
+** Each index block except for the first contains information on
+** HASHTABLE_NPAGE frames. The first index block contains information on
+** HASHTABLE_NPAGE_ONE frames. The values of HASHTABLE_NPAGE_ONE and
+** HASHTABLE_NPAGE are selected so that together the wal-index header and
+** first index block are the same size as all other index blocks in the
+** wal-index.  The values are:
+**
+**   HASHTABLE_NPAGE      4096
+**   HASHTABLE_NPAGE_ONE  4062
+**
+** Each index block contains two sections, a page-mapping that contains the
+** database page number associated with each wal frame, and a hash-table
+** that allows readers to query an index block for a specific page number.
+** The page-mapping is an array of HASHTABLE_NPAGE (or HASHTABLE_NPAGE_ONE
+** for the first index block) 32-bit page numbers. The first entry in the
+** first index-block contains the database page number corresponding to the
+** first frame in the WAL file. The first entry in the second index block
+** in the WAL file corresponds to the (HASHTABLE_NPAGE_ONE+1)th frame in
+** the log, and so on.
+**
+** The last index block in a wal-index usually contains less than the full
+** complement of HASHTABLE_NPAGE (or HASHTABLE_NPAGE_ONE) page-numbers,
+** depending on the contents of the WAL file. This does not change the
+** allocated size of the page-mapping array - the page-mapping array merely
+** contains unused entries.
+**
+** Even without using the hash table, the last frame for page P
+** can be found by scanning the page-mapping sections of each index block
+** starting with the last index block and moving toward the first, and
+** within each index block, starting at the end and moving toward the
+** beginning.  The first entry that equals P corresponds to the frame
+** holding the content for that page.
+**
+** The hash table consists of HASHTABLE_NSLOT 16-bit unsigned integers.
+** HASHTABLE_NSLOT = 2*HASHTABLE_NPAGE, and there is one entry in the
+** hash table for each page number in the mapping section, so the hash
+** table is never more than half full.  The expected number of collisions
+** prior to finding a match is 1.  Each entry of the hash table is an
+** 1-based index of an entry in the mapping section of the same
+** index block.   Let K be the 1-based index of the largest entry in
+** the mapping section.  (For index blocks other than the last, K will
+** always be exactly HASHTABLE_NPAGE (4096) and for the last index block
+** K will be (mxFrame%HASHTABLE_NPAGE).)  Unused slots of the hash table
+** contain a value of 0.
+**
+** To look for page P in the hash table, first compute a hash iKey on
+** P as follows:
+**
+**      iKey = (P * 383) % HASHTABLE_NSLOT
+**
+** Then start scanning entries of the hash table, starting with iKey
+** (wrapping around to the beginning when the end of the hash table is
+** reached) until an unused hash slot is found. Let the first unused slot
+** be at index iUnused.  (iUnused might be less than iKey if there was
+** wrap-around.) Because the hash table is never more than half full,
+** the search is guaranteed to eventually hit an unused entry.  Let
+** iMax be the value between iKey and iUnused, closest to iUnused,
+** where aHash[iMax]==P.  If there is no iMax entry (if there exists
+** no hash slot such that aHash[i]==p) then page P is not in the
+** current index block.  Otherwise the iMax-th mapping entry of the
+** current index block corresponds to the last entry that references
+** page P.
+**
+** A hash search begins with the last index block and moves toward the
+** first index block, looking for entries corresponding to page P.  On
+** average, only two or three slots in each index block need to be
+** examined in order to either find the last entry for page P, or to
+** establish that no such entry exists in the block.  Each index block
+** holds over 4000 entries.  So two or three index blocks are sufficient
+** to cover a typical 10 megabyte WAL file, assuming 1K pages.  8 or 10
+** comparisons (on average) suffice to either locate a frame in the
+** WAL or to establish that the frame does not exist in the WAL.  This
+** is much faster than scanning the entire 10MB WAL.
+**
+** Note that entries are added in order of increasing K.  Hence, one
+** reader might be using some value K0 and a second reader that started
+** at a later time (after additional transactions were added to the WAL
+** and to the wal-index) might be using a different value K1, where K1>K0.
+** Both readers can use the same hash table and mapping section to get
+** the correct result.  There may be entries in the hash table with
+** K>K0 but to the first reader, those entries will appear to be unused
+** slots in the hash table and so the first reader will get an answer as
+** if no values greater than K0 had ever been inserted into the hash table
+** in the first place - which is what reader one wants.  Meanwhile, the
+** second reader using K1 will see additional values that were inserted
+** later, which is exactly what reader two wants.
+**
+** When a rollback occurs, the value of K is decreased. Hash table entries
+** that correspond to frames greater than the new K value are removed
+** from the hash table at this point.
+*/
+#ifndef SQLITE_OMIT_WAL
+
+/* #include "wal.h" */
+
+/*
+** Trace output macros
+*/
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+SQLITE_PRIVATE int sqlite3WalTrace = 0;
+# define WALTRACE(X)  if(sqlite3WalTrace) sqlite3DebugPrintf X
+#else
+# define WALTRACE(X)
+#endif
+
+/*
+** The maximum (and only) versions of the wal and wal-index formats
+** that may be interpreted by this version of SQLite.
+**
+** If a client begins recovering a WAL file and finds that (a) the checksum
+** values in the wal-header are correct and (b) the version field is not
+** WAL_MAX_VERSION, recovery fails and SQLite returns SQLITE_CANTOPEN.
+**
+** Similarly, if a client successfully reads a wal-index header (i.e. the
+** checksum test is successful) and finds that the version field is not
+** WALINDEX_MAX_VERSION, then no read-transaction is opened and SQLite
+** returns SQLITE_CANTOPEN.
+*/
+#define WAL_MAX_VERSION      3007000
+#define WALINDEX_MAX_VERSION 3007000
+
+/*
+** Index numbers for various locking bytes.   WAL_NREADER is the number
+** of available reader locks and should be at least 3.  The default
+** is SQLITE_SHM_NLOCK==8 and  WAL_NREADER==5.
+**
+** Technically, the various VFSes are free to implement these locks however
+** they see fit.  However, compatibility is encouraged so that VFSes can
+** interoperate.  The standard implementation used on both unix and windows
+** is for the index number to indicate a byte offset into the
+** WalCkptInfo.aLock[] array in the wal-index header.  In other words, all
+** locks are on the shm file.  The WALINDEX_LOCK_OFFSET constant (which
+** should be 120) is the location in the shm file for the first locking
+** byte.
+*/
+#define WAL_WRITE_LOCK         0
+#define WAL_ALL_BUT_WRITE      1
+#define WAL_CKPT_LOCK          1
+#define WAL_RECOVER_LOCK       2
+#define WAL_READ_LOCK(I)       (3+(I))
+#define WAL_NREADER            (SQLITE_SHM_NLOCK-3)
+
+
+/* Object declarations */
+typedef struct WalIndexHdr WalIndexHdr;
+typedef struct WalIterator WalIterator;
+typedef struct WalCkptInfo WalCkptInfo;
+
+
+/*
+** The following object holds a copy of the wal-index header content.
+**
+** The actual header in the wal-index consists of two copies of this
+** object followed by one instance of the WalCkptInfo object.
+** For all versions of SQLite through 3.10.0 and probably beyond,
+** the locking bytes (WalCkptInfo.aLock) start at offset 120 and
+** the total header size is 136 bytes.
+**
+** The szPage value can be any power of 2 between 512 and 32768, inclusive.
+** Or it can be 1 to represent a 65536-byte page.  The latter case was
+** added in 3.7.1 when support for 64K pages was added.
+*/
+struct WalIndexHdr {
+  u32 iVersion;                   /* Wal-index version */
+  u32 unused;                     /* Unused (padding) field */
+  u32 iChange;                    /* Counter incremented each transaction */
+  u8 isInit;                      /* 1 when initialized */
+  u8 bigEndCksum;                 /* True if checksums in WAL are big-endian */
+  u16 szPage;                     /* Database page size in bytes. 1==64K */
+  u32 mxFrame;                    /* Index of last valid frame in the WAL */
+  u32 nPage;                      /* Size of database in pages */
+  u32 aFrameCksum[2];             /* Checksum of last frame in log */
+  u32 aSalt[2];                   /* Two salt values copied from WAL header */
+  u32 aCksum[2];                  /* Checksum over all prior fields */
+};
+
+/*
+** A copy of the following object occurs in the wal-index immediately
+** following the second copy of the WalIndexHdr.  This object stores
+** information used by checkpoint.
+**
+** nBackfill is the number of frames in the WAL that have been written
+** back into the database. (We call the act of moving content from WAL to
+** database "backfilling".)  The nBackfill number is never greater than
+** WalIndexHdr.mxFrame.  nBackfill can only be increased by threads
+** holding the WAL_CKPT_LOCK lock (which includes a recovery thread).
+** However, a WAL_WRITE_LOCK thread can move the value of nBackfill from
+** mxFrame back to zero when the WAL is reset.
+**
+** nBackfillAttempted is the largest value of nBackfill that a checkpoint
+** has attempted to achieve.  Normally nBackfill==nBackfillAtempted, however
+** the nBackfillAttempted is set before any backfilling is done and the
+** nBackfill is only set after all backfilling completes.  So if a checkpoint
+** crashes, nBackfillAttempted might be larger than nBackfill.  The
+** WalIndexHdr.mxFrame must never be less than nBackfillAttempted.
+**
+** The aLock[] field is a set of bytes used for locking.  These bytes should
+** never be read or written.
+**
+** There is one entry in aReadMark[] for each reader lock.  If a reader
+** holds read-lock K, then the value in aReadMark[K] is no greater than
+** the mxFrame for that reader.  The value READMARK_NOT_USED (0xffffffff)
+** for any aReadMark[] means that entry is unused.  aReadMark[0] is
+** a special case; its value is never used and it exists as a place-holder
+** to avoid having to offset aReadMark[] indexes by one.  Readers holding
+** WAL_READ_LOCK(0) always ignore the entire WAL and read all content
+** directly from the database.
+**
+** The value of aReadMark[K] may only be changed by a thread that
+** is holding an exclusive lock on WAL_READ_LOCK(K).  Thus, the value of
+** aReadMark[K] cannot changed while there is a reader is using that mark
+** since the reader will be holding a shared lock on WAL_READ_LOCK(K).
+**
+** The checkpointer may only transfer frames from WAL to database where
+** the frame numbers are less than or equal to every aReadMark[] that is
+** in use (that is, every aReadMark[j] for which there is a corresponding
+** WAL_READ_LOCK(j)).  New readers (usually) pick the aReadMark[] with the
+** largest value and will increase an unused aReadMark[] to mxFrame if there
+** is not already an aReadMark[] equal to mxFrame.  The exception to the
+** previous sentence is when nBackfill equals mxFrame (meaning that everything
+** in the WAL has been backfilled into the database) then new readers
+** will choose aReadMark[0] which has value 0 and hence such reader will
+** get all their all content directly from the database file and ignore
+** the WAL.
+**
+** Writers normally append new frames to the end of the WAL.  However,
+** if nBackfill equals mxFrame (meaning that all WAL content has been
+** written back into the database) and if no readers are using the WAL
+** (in other words, if there are no WAL_READ_LOCK(i) where i>0) then
+** the writer will first "reset" the WAL back to the beginning and start
+** writing new content beginning at frame 1.
+**
+** We assume that 32-bit loads are atomic and so no locks are needed in
+** order to read from any aReadMark[] entries.
+*/
+struct WalCkptInfo {
+  u32 nBackfill;                  /* Number of WAL frames backfilled into DB */
+  u32 aReadMark[WAL_NREADER];     /* Reader marks */
+  u8 aLock[SQLITE_SHM_NLOCK];     /* Reserved space for locks */
+  u32 nBackfillAttempted;         /* WAL frames perhaps written, or maybe not */
+  u32 notUsed0;                   /* Available for future enhancements */
+};
+#define READMARK_NOT_USED  0xffffffff
+
+/*
+** This is a schematic view of the complete 136-byte header of the
+** wal-index file (also known as the -shm file):
+**
+**      +-----------------------------+
+**   0: | iVersion                    | \
+**      +-----------------------------+  |
+**   4: | (unused padding)            |  |
+**      +-----------------------------+  |
+**   8: | iChange                     |  |
+**      +-------+-------+-------------+  |
+**  12: | bInit |  bBig |   szPage    |  |
+**      +-------+-------+-------------+  |
+**  16: | mxFrame                     |  |  First copy of the
+**      +-----------------------------+  |  WalIndexHdr object
+**  20: | nPage                       |  |
+**      +-----------------------------+  |
+**  24: | aFrameCksum                 |  |
+**      |                             |  |
+**      +-----------------------------+  |
+**  32: | aSalt                       |  |
+**      |                             |  |
+**      +-----------------------------+  |
+**  40: | aCksum                      |  |
+**      |                             | /
+**      +-----------------------------+
+**  48: | iVersion                    | \
+**      +-----------------------------+  |
+**  52: | (unused padding)            |  |
+**      +-----------------------------+  |
+**  56: | iChange                     |  |
+**      +-------+-------+-------------+  |
+**  60: | bInit |  bBig |   szPage    |  |
+**      +-------+-------+-------------+  |  Second copy of the
+**  64: | mxFrame                     |  |  WalIndexHdr
+**      +-----------------------------+  |
+**  68: | nPage                       |  |
+**      +-----------------------------+  |
+**  72: | aFrameCksum                 |  |
+**      |                             |  |
+**      +-----------------------------+  |
+**  80: | aSalt                       |  |
+**      |                             |  |
+**      +-----------------------------+  |
+**  88: | aCksum                      |  |
+**      |                             | /
+**      +-----------------------------+
+**  96: | nBackfill                   |
+**      +-----------------------------+
+** 100: | 5 read marks                |
+**      |                             |
+**      |                             |
+**      |                             |
+**      |                             |
+**      +-------+-------+------+------+
+** 120: | Write | Ckpt  | Rcvr | Rd0  | \
+**      +-------+-------+------+------+  ) 8 lock bytes
+**      | Read1 | Read2 | Rd3  | Rd4  | /
+**      +-------+-------+------+------+
+** 128: | nBackfillAttempted          |
+**      +-----------------------------+
+** 132: | (unused padding)            |
+**      +-----------------------------+
+*/
+
+/* A block of WALINDEX_LOCK_RESERVED bytes beginning at
+** WALINDEX_LOCK_OFFSET is reserved for locks. Since some systems
+** only support mandatory file-locks, we do not read or write data
+** from the region of the file on which locks are applied.
+*/
+#define WALINDEX_LOCK_OFFSET (sizeof(WalIndexHdr)*2+offsetof(WalCkptInfo,aLock))
+#define WALINDEX_HDR_SIZE    (sizeof(WalIndexHdr)*2+sizeof(WalCkptInfo))
+
+/* Size of header before each frame in wal */
+#define WAL_FRAME_HDRSIZE 24
+
+/* Size of write ahead log header, including checksum. */
+#define WAL_HDRSIZE 32
+
+/* WAL magic value. Either this value, or the same value with the least
+** significant bit also set (WAL_MAGIC | 0x00000001) is stored in 32-bit
+** big-endian format in the first 4 bytes of a WAL file.
+**
+** If the LSB is set, then the checksums for each frame within the WAL
+** file are calculated by treating all data as an array of 32-bit
+** big-endian words. Otherwise, they are calculated by interpreting
+** all data as 32-bit little-endian words.
+*/
+#define WAL_MAGIC 0x377f0682
+
+/*
+** Return the offset of frame iFrame in the write-ahead log file,
+** assuming a database page size of szPage bytes. The offset returned
+** is to the start of the write-ahead log frame-header.
+*/
+#define walFrameOffset(iFrame, szPage) (                               \
+  WAL_HDRSIZE + ((iFrame)-1)*(i64)((szPage)+WAL_FRAME_HDRSIZE)         \
+)
+
+/*
+** An open write-ahead log file is represented by an instance of the
+** following object.
+*/
+struct Wal {
+  sqlite3_vfs *pVfs;         /* The VFS used to create pDbFd */
+  sqlite3_file *pDbFd;       /* File handle for the database file */
+  sqlite3_file *pWalFd;      /* File handle for WAL file */
+  u32 iCallback;             /* Value to pass to log callback (or 0) */
+  i64 mxWalSize;             /* Truncate WAL to this size upon reset */
+  int nWiData;               /* Size of array apWiData */
+  int szFirstBlock;          /* Size of first block written to WAL file */
+  volatile u32 **apWiData;   /* Pointer to wal-index content in memory */
+  u32 szPage;                /* Database page size */
+  i16 readLock;              /* Which read lock is being held.  -1 for none */
+  u8 syncFlags;              /* Flags to use to sync header writes */
+  u8 exclusiveMode;          /* Non-zero if connection is in exclusive mode */
+  u8 writeLock;              /* True if in a write transaction */
+  u8 ckptLock;               /* True if holding a checkpoint lock */
+  u8 readOnly;               /* WAL_RDWR, WAL_RDONLY, or WAL_SHM_RDONLY */
+  u8 truncateOnCommit;       /* True to truncate WAL file on commit */
+  u8 syncHeader;             /* Fsync the WAL header if true */
+  u8 padToSectorBoundary;    /* Pad transactions out to the next sector */
+  u8 bShmUnreliable;         /* SHM content is read-only and unreliable */
+  WalIndexHdr hdr;           /* Wal-index header for current transaction */
+  u32 minFrame;              /* Ignore wal frames before this one */
+  u32 iReCksum;              /* On commit, recalculate checksums from here */
+  const char *zWalName;      /* Name of WAL file */
+  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
+#ifdef SQLITE_USE_SEH
+  u32 lockMask;              /* Mask of locks held */
+  void *pFree;               /* Pointer to sqlite3_free() if exception thrown */
+  u32 *pWiValue;             /* Value to write into apWiData[iWiPg] */
+  int iWiPg;                 /* Write pWiValue into apWiData[iWiPg] */
+  int iSysErrno;             /* System error code following exception */
+#endif
+#ifdef SQLITE_DEBUG
+  int nSehTry;               /* Number of nested SEH_TRY{} blocks */
+  u8 lockError;              /* True if a locking error has occurred */
+#endif
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  WalIndexHdr *pSnapshot;    /* Start transaction here if not NULL */
+  int bGetSnapshot;          /* Transaction opened for sqlite3_get_snapshot() */
+#endif
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  sqlite3 *db;
+#endif
+};
+
+/*
+** Candidate values for Wal.exclusiveMode.
+*/
+#define WAL_NORMAL_MODE     0
+#define WAL_EXCLUSIVE_MODE  1
+#define WAL_HEAPMEMORY_MODE 2
+
+/*
+** Possible values for WAL.readOnly
+*/
+#define WAL_RDWR        0    /* Normal read/write connection */
+#define WAL_RDONLY      1    /* The WAL file is readonly */
+#define WAL_SHM_RDONLY  2    /* The SHM file is readonly */
+
+/*
+** Each page of the wal-index mapping contains a hash-table made up of
+** an array of HASHTABLE_NSLOT elements of the following type.
+*/
+typedef u16 ht_slot;
+
+/*
+** This structure is used to implement an iterator that loops through
+** all frames in the WAL in database page order. Where two or more frames
+** correspond to the same database page, the iterator visits only the
+** frame most recently written to the WAL (in other words, the frame with
+** the largest index).
+**
+** The internals of this structure are only accessed by:
+**
+**   walIteratorInit() - Create a new iterator,
+**   walIteratorNext() - Step an iterator,
+**   walIteratorFree() - Free an iterator.
+**
+** This functionality is used by the checkpoint code (see walCheckpoint()).
+*/
+struct WalIterator {
+  u32 iPrior;                     /* Last result returned from the iterator */
+  int nSegment;                   /* Number of entries in aSegment[] */
+  struct WalSegment {
+    int iNext;                    /* Next slot in aIndex[] not yet returned */
+    ht_slot *aIndex;              /* i0, i1, i2... such that aPgno[iN] ascend */
+    u32 *aPgno;                   /* Array of page numbers. */
+    int nEntry;                   /* Nr. of entries in aPgno[] and aIndex[] */
+    int iZero;                    /* Frame number associated with aPgno[0] */
+  } aSegment[1];                  /* One for every 32KB page in the wal-index */
+};
+
+/*
+** Define the parameters of the hash tables in the wal-index file. There
+** is a hash-table following every HASHTABLE_NPAGE page numbers in the
+** wal-index.
+**
+** Changing any of these constants will alter the wal-index format and
+** create incompatibilities.
+*/
+#define HASHTABLE_NPAGE      4096                 /* Must be power of 2 */
+#define HASHTABLE_HASH_1     383                  /* Should be prime */
+#define HASHTABLE_NSLOT      (HASHTABLE_NPAGE*2)  /* Must be a power of 2 */
+
+/*
+** The block of page numbers associated with the first hash-table in a
+** wal-index is smaller than usual. This is so that there is a complete
+** hash-table on each aligned 32KB page of the wal-index.
+*/
+#define HASHTABLE_NPAGE_ONE  (HASHTABLE_NPAGE - (WALINDEX_HDR_SIZE/sizeof(u32)))
+
+/* The wal-index is divided into pages of WALINDEX_PGSZ bytes each. */
+#define WALINDEX_PGSZ   (                                         \
+    sizeof(ht_slot)*HASHTABLE_NSLOT + HASHTABLE_NPAGE*sizeof(u32) \
+)
+
+/*
+** Structured Exception Handling (SEH) is a Windows-specific technique
+** for catching exceptions raised while accessing memory-mapped files.
+**
+** The -DSQLITE_USE_SEH compile-time option means to use SEH to catch and
+** deal with system-level errors that arise during WAL -shm file processing.
+** Without this compile-time option, any system-level faults that appear
+** while accessing the memory-mapped -shm file will cause a process-wide
+** signal to be deliver, which will more than likely cause the entire
+** process to exit.
+*/
+#ifdef SQLITE_USE_SEH
+#include <Windows.h>
+
+/* Beginning of a block of code in which an exception might occur */
+# define SEH_TRY    __try { \
+   assert( walAssertLockmask(pWal) && pWal->nSehTry==0 ); \
+   VVA_ONLY(pWal->nSehTry++);
+
+/* The end of a block of code in which an exception might occur */
+# define SEH_EXCEPT(X) \
+   VVA_ONLY(pWal->nSehTry--); \
+   assert( pWal->nSehTry==0 ); \
+   } __except( sehExceptionFilter(pWal, GetExceptionCode(), GetExceptionInformation() ) ){ X }
+
+/* Simulate a memory-mapping fault in the -shm file for testing purposes */
+# define SEH_INJECT_FAULT sehInjectFault(pWal)
+
+/*
+** The second argument is the return value of GetExceptionCode() for the
+** current exception. Return EXCEPTION_EXECUTE_HANDLER if the exception code
+** indicates that the exception may have been caused by accessing the *-shm
+** file mapping. Or EXCEPTION_CONTINUE_SEARCH otherwise.
+*/
+static int sehExceptionFilter(Wal *pWal, int eCode, EXCEPTION_POINTERS *p){
+  VVA_ONLY(pWal->nSehTry--);
+  if( eCode==EXCEPTION_IN_PAGE_ERROR ){
+    if( p && p->ExceptionRecord && p->ExceptionRecord->NumberParameters>=3 ){
+      /* From MSDN: For this type of exception, the first element of the
+      ** ExceptionInformation[] array is a read-write flag - 0 if the exception
+      ** was thrown while reading, 1 if while writing. The second element is
+      ** the virtual address being accessed. The "third array element specifies
+      ** the underlying NTSTATUS code that resulted in the exception". */
+      pWal->iSysErrno = (int)p->ExceptionRecord->ExceptionInformation[2];
+    }
+    return EXCEPTION_EXECUTE_HANDLER;
+  }
+  return EXCEPTION_CONTINUE_SEARCH;
+}
+
+/*
+** If one is configured, invoke the xTestCallback callback with 650 as
+** the argument. If it returns true, throw the same exception that is
+** thrown by the system if the *-shm file mapping is accessed after it
+** has been invalidated.
+*/
+static void sehInjectFault(Wal *pWal){
+  int res;
+  assert( pWal->nSehTry>0 );
+
+  res = sqlite3FaultSim(650);
+  if( res!=0 ){
+    ULONG_PTR aArg[3];
+    aArg[0] = 0;
+    aArg[1] = 0;
+    aArg[2] = (ULONG_PTR)res;
+    RaiseException(EXCEPTION_IN_PAGE_ERROR, 0, 3, (const ULONG_PTR*)aArg);
+  }
+}
+
+/*
+** There are two ways to use this macro. To set a pointer to be freed
+** if an exception is thrown:
+**
+**   SEH_FREE_ON_ERROR(0, pPtr);
+**
+** and to cancel the same:
+**
+**   SEH_FREE_ON_ERROR(pPtr, 0);
+**
+** In the first case, there must not already be a pointer registered to
+** be freed. In the second case, pPtr must be the registered pointer.
+*/
+#define SEH_FREE_ON_ERROR(X,Y) \
+  assert( (X==0 || Y==0) && pWal->pFree==X ); pWal->pFree = Y
+
+/*
+** There are two ways to use this macro. To arrange for pWal->apWiData[iPg]
+** to be set to pValue if an exception is thrown:
+**
+**   SEH_SET_ON_ERROR(iPg, pValue);
+**
+** and to cancel the same:
+**
+**   SEH_SET_ON_ERROR(0, 0);
+*/
+#define SEH_SET_ON_ERROR(X,Y)  pWal->iWiPg = X; pWal->pWiValue = Y
+
+#else
+# define SEH_TRY          VVA_ONLY(pWal->nSehTry++);
+# define SEH_EXCEPT(X)    VVA_ONLY(pWal->nSehTry--); assert( pWal->nSehTry==0 );
+# define SEH_INJECT_FAULT assert( pWal->nSehTry>0 );
+# define SEH_FREE_ON_ERROR(X,Y)
+# define SEH_SET_ON_ERROR(X,Y)
+#endif /* ifdef SQLITE_USE_SEH */
+
+
+/*
+** Obtain a pointer to the iPage'th page of the wal-index. The wal-index
+** is broken into pages of WALINDEX_PGSZ bytes. Wal-index pages are
+** numbered from zero.
+**
+** If the wal-index is currently smaller the iPage pages then the size
+** of the wal-index might be increased, but only if it is safe to do
+** so.  It is safe to enlarge the wal-index if pWal->writeLock is true
+** or pWal->exclusiveMode==WAL_HEAPMEMORY_MODE.
+**
+** Three possible result scenarios:
+**
+**   (1)  rc==SQLITE_OK    and *ppPage==Requested-Wal-Index-Page
+**   (2)  rc>=SQLITE_ERROR and *ppPage==NULL
+**   (3)  rc==SQLITE_OK    and *ppPage==NULL  // only if iPage==0
+**
+** Scenario (3) can only occur when pWal->writeLock is false and iPage==0
+*/
+static SQLITE_NOINLINE int walIndexPageRealloc(
+  Wal *pWal,               /* The WAL context */
+  int iPage,               /* The page we seek */
+  volatile u32 **ppPage    /* Write the page pointer here */
+){
+  int rc = SQLITE_OK;
+
+  /* Enlarge the pWal->apWiData[] array if required */
+  if( pWal->nWiData<=iPage ){
+    sqlite3_int64 nByte = sizeof(u32*)*(iPage+1);
+    volatile u32 **apNew;
+    apNew = (volatile u32 **)sqlite3Realloc((void *)pWal->apWiData, nByte);
+    if( !apNew ){
+      *ppPage = 0;
+      return SQLITE_NOMEM_BKPT;
+    }
+    memset((void*)&apNew[pWal->nWiData], 0,
+           sizeof(u32*)*(iPage+1-pWal->nWiData));
+    pWal->apWiData = apNew;
+    pWal->nWiData = iPage+1;
+  }
+
+  /* Request a pointer to the required page from the VFS */
+  assert( pWal->apWiData[iPage]==0 );
+  if( pWal->exclusiveMode==WAL_HEAPMEMORY_MODE ){
+    pWal->apWiData[iPage] = (u32 volatile *)sqlite3MallocZero(WALINDEX_PGSZ);
+    if( !pWal->apWiData[iPage] ) rc = SQLITE_NOMEM_BKPT;
+  }else{
+    rc = sqlite3OsShmMap(pWal->pDbFd, iPage, WALINDEX_PGSZ,
+        pWal->writeLock, (void volatile **)&pWal->apWiData[iPage]
+    );
+    assert( pWal->apWiData[iPage]!=0
+         || rc!=SQLITE_OK
+         || (pWal->writeLock==0 && iPage==0) );
+    testcase( pWal->apWiData[iPage]==0 && rc==SQLITE_OK );
+    if( rc==SQLITE_OK ){
+      if( iPage>0 && sqlite3FaultSim(600) ) rc = SQLITE_NOMEM;
+    }else if( (rc&0xff)==SQLITE_READONLY ){
+      pWal->readOnly |= WAL_SHM_RDONLY;
+      if( rc==SQLITE_READONLY ){
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+  *ppPage = pWal->apWiData[iPage];
+  assert( iPage==0 || *ppPage || rc!=SQLITE_OK );
+  return rc;
+}
+static int walIndexPage(
+  Wal *pWal,               /* The WAL context */
+  int iPage,               /* The page we seek */
+  volatile u32 **ppPage    /* Write the page pointer here */
+){
+  SEH_INJECT_FAULT;
+  if( pWal->nWiData<=iPage || (*ppPage = pWal->apWiData[iPage])==0 ){
+    return walIndexPageRealloc(pWal, iPage, ppPage);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return a pointer to the WalCkptInfo structure in the wal-index.
+*/
+static volatile WalCkptInfo *walCkptInfo(Wal *pWal){
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+  SEH_INJECT_FAULT;
+  return (volatile WalCkptInfo*)&(pWal->apWiData[0][sizeof(WalIndexHdr)/2]);
+}
+
+/*
+** Return a pointer to the WalIndexHdr structure in the wal-index.
+*/
+static volatile WalIndexHdr *walIndexHdr(Wal *pWal){
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+  SEH_INJECT_FAULT;
+  return (volatile WalIndexHdr*)pWal->apWiData[0];
+}
+
+/*
+** The argument to this macro must be of type u32. On a little-endian
+** architecture, it returns the u32 value that results from interpreting
+** the 4 bytes as a big-endian value. On a big-endian architecture, it
+** returns the value that would be produced by interpreting the 4 bytes
+** of the input value as a little-endian integer.
+*/
+#define BYTESWAP32(x) ( \
+    (((x)&0x000000FF)<<24) + (((x)&0x0000FF00)<<8)  \
+  + (((x)&0x00FF0000)>>8)  + (((x)&0xFF000000)>>24) \
+)
+
+/*
+** Generate or extend an 8 byte checksum based on the data in
+** array aByte[] and the initial values of aIn[0] and aIn[1] (or
+** initial values of 0 and 0 if aIn==NULL).
+**
+** The checksum is written back into aOut[] before returning.
+**
+** nByte must be a positive multiple of 8.
+*/
+static void walChecksumBytes(
+  int nativeCksum, /* True for native byte-order, false for non-native */
+  u8 *a,           /* Content to be checksummed */
+  int nByte,       /* Bytes of content in a[].  Must be a multiple of 8. */
+  const u32 *aIn,  /* Initial checksum value input */
+  u32 *aOut        /* OUT: Final checksum value output */
+){
+  u32 s1, s2;
+  u32 *aData = (u32 *)a;
+  u32 *aEnd = (u32 *)&a[nByte];
+
+  if( aIn ){
+    s1 = aIn[0];
+    s2 = aIn[1];
+  }else{
+    s1 = s2 = 0;
+  }
+
+  assert( nByte>=8 );
+  assert( (nByte&0x00000007)==0 );
+  assert( nByte<=65536 );
+  assert( nByte%4==0 );
+
+  if( !nativeCksum ){
+    do {
+      s1 += BYTESWAP32(aData[0]) + s2;
+      s2 += BYTESWAP32(aData[1]) + s1;
+      aData += 2;
+    }while( aData<aEnd );
+  }else if( nByte%64==0 ){
+    do {
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+    }while( aData<aEnd );
+  }else{
+    do {
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+    }while( aData<aEnd );
+  }
+  assert( aData==aEnd );
+
+  aOut[0] = s1;
+  aOut[1] = s2;
+}
+
+/*
+** If there is the possibility of concurrent access to the SHM file
+** from multiple threads and/or processes, then do a memory barrier.
+*/
+static void walShmBarrier(Wal *pWal){
+  if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
+    sqlite3OsShmBarrier(pWal->pDbFd);
+  }
+}
+
+/*
+** Add the SQLITE_NO_TSAN as part of the return-type of a function
+** definition as a hint that the function contains constructs that
+** might give false-positive TSAN warnings.
+**
+** See tag-20200519-1.
+*/
+#if defined(__clang__) && !defined(SQLITE_NO_TSAN)
+# define SQLITE_NO_TSAN __attribute__((no_sanitize_thread))
+#else
+# define SQLITE_NO_TSAN
+#endif
+
+/*
+** Write the header information in pWal->hdr into the wal-index.
+**
+** The checksum on pWal->hdr is updated before it is written.
+*/
+static SQLITE_NO_TSAN void walIndexWriteHdr(Wal *pWal){
+  volatile WalIndexHdr *aHdr = walIndexHdr(pWal);
+  const int nCksum = offsetof(WalIndexHdr, aCksum);
+
+  assert( pWal->writeLock );
+  pWal->hdr.isInit = 1;
+  pWal->hdr.iVersion = WALINDEX_MAX_VERSION;
+  walChecksumBytes(1, (u8*)&pWal->hdr, nCksum, 0, pWal->hdr.aCksum);
+  /* Possible TSAN false-positive.  See tag-20200519-1 */
+  memcpy((void*)&aHdr[1], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
+  walShmBarrier(pWal);
+  memcpy((void*)&aHdr[0], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
+}
+
+/*
+** This function encodes a single frame header and writes it to a buffer
+** supplied by the caller. A frame-header is made up of a series of
+** 4-byte big-endian integers, as follows:
+**
+**     0: Page number.
+**     4: For commit records, the size of the database image in pages
+**        after the commit. For all other records, zero.
+**     8: Salt-1 (copied from the wal-header)
+**    12: Salt-2 (copied from the wal-header)
+**    16: Checksum-1.
+**    20: Checksum-2.
+*/
+static void walEncodeFrame(
+  Wal *pWal,                      /* The write-ahead log */
+  u32 iPage,                      /* Database page number for frame */
+  u32 nTruncate,                  /* New db size (or 0 for non-commit frames) */
+  u8 *aData,                      /* Pointer to page data */
+  u8 *aFrame                      /* OUT: Write encoded frame here */
+){
+  int nativeCksum;                /* True for native byte-order checksums */
+  u32 *aCksum = pWal->hdr.aFrameCksum;
+  assert( WAL_FRAME_HDRSIZE==24 );
+  sqlite3Put4byte(&aFrame[0], iPage);
+  sqlite3Put4byte(&aFrame[4], nTruncate);
+  if( pWal->iReCksum==0 ){
+    memcpy(&aFrame[8], pWal->hdr.aSalt, 8);
+
+    nativeCksum = (pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN);
+    walChecksumBytes(nativeCksum, aFrame, 8, aCksum, aCksum);
+    walChecksumBytes(nativeCksum, aData, pWal->szPage, aCksum, aCksum);
+
+    sqlite3Put4byte(&aFrame[16], aCksum[0]);
+    sqlite3Put4byte(&aFrame[20], aCksum[1]);
+  }else{
+    memset(&aFrame[8], 0, 16);
+  }
+}
+
+/*
+** Check to see if the frame with header in aFrame[] and content
+** in aData[] is valid.  If it is a valid frame, fill *piPage and
+** *pnTruncate and return true.  Return if the frame is not valid.
+*/
+static int walDecodeFrame(
+  Wal *pWal,                      /* The write-ahead log */
+  u32 *piPage,                    /* OUT: Database page number for frame */
+  u32 *pnTruncate,                /* OUT: New db size (or 0 if not commit) */
+  u8 *aData,                      /* Pointer to page data (for checksum) */
+  u8 *aFrame                      /* Frame data */
+){
+  int nativeCksum;                /* True for native byte-order checksums */
+  u32 *aCksum = pWal->hdr.aFrameCksum;
+  u32 pgno;                       /* Page number of the frame */
+  assert( WAL_FRAME_HDRSIZE==24 );
+
+  /* A frame is only valid if the salt values in the frame-header
+  ** match the salt values in the wal-header.
+  */
+  if( memcmp(&pWal->hdr.aSalt, &aFrame[8], 8)!=0 ){
+    return 0;
+  }
+
+  /* A frame is only valid if the page number is greater than zero.
+  */
+  pgno = sqlite3Get4byte(&aFrame[0]);
+  if( pgno==0 ){
+    return 0;
+  }
+
+  /* A frame is only valid if a checksum of the WAL header,
+  ** all prior frames, the first 16 bytes of this frame-header,
+  ** and the frame-data matches the checksum in the last 8
+  ** bytes of this frame-header.
+  */
+  nativeCksum = (pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN);
+  walChecksumBytes(nativeCksum, aFrame, 8, aCksum, aCksum);
+  walChecksumBytes(nativeCksum, aData, pWal->szPage, aCksum, aCksum);
+  if( aCksum[0]!=sqlite3Get4byte(&aFrame[16])
+   || aCksum[1]!=sqlite3Get4byte(&aFrame[20])
+  ){
+    /* Checksum failed. */
+    return 0;
+  }
+
+  /* If we reach this point, the frame is valid.  Return the page number
+  ** and the new database size.
+  */
+  *piPage = pgno;
+  *pnTruncate = sqlite3Get4byte(&aFrame[4]);
+  return 1;
+}
+
+
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+/*
+** Names of locks.  This routine is used to provide debugging output and is not
+** a part of an ordinary build.
+*/
+static const char *walLockName(int lockIdx){
+  if( lockIdx==WAL_WRITE_LOCK ){
+    return "WRITE-LOCK";
+  }else if( lockIdx==WAL_CKPT_LOCK ){
+    return "CKPT-LOCK";
+  }else if( lockIdx==WAL_RECOVER_LOCK ){
+    return "RECOVER-LOCK";
+  }else{
+    static char zName[15];
+    sqlite3_snprintf(sizeof(zName), zName, "READ-LOCK[%d]",
+                     lockIdx-WAL_READ_LOCK(0));
+    return zName;
+  }
+}
+#endif /*defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */
+
+
+/*
+** Set or release locks on the WAL.  Locks are either shared or exclusive.
+** A lock cannot be moved directly between shared and exclusive - it must go
+** through the unlocked state first.
+**
+** In locking_mode=EXCLUSIVE, all of these routines become no-ops.
+*/
+static int walLockShared(Wal *pWal, int lockIdx){
+  int rc;
+  if( pWal->exclusiveMode ) return SQLITE_OK;
+  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
+                        SQLITE_SHM_LOCK | SQLITE_SHM_SHARED);
+  WALTRACE(("WAL%p: acquire SHARED-%s %s\n", pWal,
+            walLockName(lockIdx), rc ? "failed" : "ok"));
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && (rc&0xFF)!=SQLITE_BUSY); )
+#ifdef SQLITE_USE_SEH
+  if( rc==SQLITE_OK ) pWal->lockMask |= (1 << lockIdx);
+#endif
+  return rc;
+}
+static void walUnlockShared(Wal *pWal, int lockIdx){
+  if( pWal->exclusiveMode ) return;
+  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
+                         SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED);
+#ifdef SQLITE_USE_SEH
+  pWal->lockMask &= ~(1 << lockIdx);
+#endif
+  WALTRACE(("WAL%p: release SHARED-%s\n", pWal, walLockName(lockIdx)));
+}
+static int walLockExclusive(Wal *pWal, int lockIdx, int n){
+  int rc;
+  if( pWal->exclusiveMode ) return SQLITE_OK;
+  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
+                        SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE);
+  WALTRACE(("WAL%p: acquire EXCLUSIVE-%s cnt=%d %s\n", pWal,
+            walLockName(lockIdx), n, rc ? "failed" : "ok"));
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && (rc&0xFF)!=SQLITE_BUSY); )
+#ifdef SQLITE_USE_SEH
+  if( rc==SQLITE_OK ){
+    pWal->lockMask |= (((1<<n)-1) << (SQLITE_SHM_NLOCK+lockIdx));
+  }
+#endif
+  return rc;
+}
+static void walUnlockExclusive(Wal *pWal, int lockIdx, int n){
+  if( pWal->exclusiveMode ) return;
+  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
+                         SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE);
+#ifdef SQLITE_USE_SEH
+  pWal->lockMask &= ~(((1<<n)-1) << (SQLITE_SHM_NLOCK+lockIdx));
+#endif
+  WALTRACE(("WAL%p: release EXCLUSIVE-%s cnt=%d\n", pWal,
+             walLockName(lockIdx), n));
+}
+
+/*
+** Compute a hash on a page number.  The resulting hash value must land
+** between 0 and (HASHTABLE_NSLOT-1).  The walHashNext() function advances
+** the hash to the next value in the event of a collision.
+*/
+static int walHash(u32 iPage){
+  assert( iPage>0 );
+  assert( (HASHTABLE_NSLOT & (HASHTABLE_NSLOT-1))==0 );
+  return (iPage*HASHTABLE_HASH_1) & (HASHTABLE_NSLOT-1);
+}
+static int walNextHash(int iPriorHash){
+  return (iPriorHash+1)&(HASHTABLE_NSLOT-1);
+}
+
+/*
+** An instance of the WalHashLoc object is used to describe the location
+** of a page hash table in the wal-index.  This becomes the return value
+** from walHashGet().
+*/
+typedef struct WalHashLoc WalHashLoc;
+struct WalHashLoc {
+  volatile ht_slot *aHash;  /* Start of the wal-index hash table */
+  volatile u32 *aPgno;      /* aPgno[1] is the page of first frame indexed */
+  u32 iZero;                /* One less than the frame number of first indexed*/
+};
+
+/*
+** Return pointers to the hash table and page number array stored on
+** page iHash of the wal-index. The wal-index is broken into 32KB pages
+** numbered starting from 0.
+**
+** Set output variable pLoc->aHash to point to the start of the hash table
+** in the wal-index file. Set pLoc->iZero to one less than the frame
+** number of the first frame indexed by this hash table. If a
+** slot in the hash table is set to N, it refers to frame number
+** (pLoc->iZero+N) in the log.
+**
+** Finally, set pLoc->aPgno so that pLoc->aPgno[0] is the page number of the
+** first frame indexed by the hash table, frame (pLoc->iZero).
+*/
+static int walHashGet(
+  Wal *pWal,                      /* WAL handle */
+  int iHash,                      /* Find the iHash'th table */
+  WalHashLoc *pLoc                /* OUT: Hash table location */
+){
+  int rc;                         /* Return code */
+
+  rc = walIndexPage(pWal, iHash, &pLoc->aPgno);
+  assert( rc==SQLITE_OK || iHash>0 );
+
+  if( pLoc->aPgno ){
+    pLoc->aHash = (volatile ht_slot *)&pLoc->aPgno[HASHTABLE_NPAGE];
+    if( iHash==0 ){
+      pLoc->aPgno = &pLoc->aPgno[WALINDEX_HDR_SIZE/sizeof(u32)];
+      pLoc->iZero = 0;
+    }else{
+      pLoc->iZero = HASHTABLE_NPAGE_ONE + (iHash-1)*HASHTABLE_NPAGE;
+    }
+  }else if( NEVER(rc==SQLITE_OK) ){
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** Return the number of the wal-index page that contains the hash-table
+** and page-number array that contain entries corresponding to WAL frame
+** iFrame. The wal-index is broken up into 32KB pages. Wal-index pages
+** are numbered starting from 0.
+*/
+static int walFramePage(u32 iFrame){
+  int iHash = (iFrame+HASHTABLE_NPAGE-HASHTABLE_NPAGE_ONE-1) / HASHTABLE_NPAGE;
+  assert( (iHash==0 || iFrame>HASHTABLE_NPAGE_ONE)
+       && (iHash>=1 || iFrame<=HASHTABLE_NPAGE_ONE)
+       && (iHash<=1 || iFrame>(HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE))
+       && (iHash>=2 || iFrame<=HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE)
+       && (iHash<=2 || iFrame>(HASHTABLE_NPAGE_ONE+2*HASHTABLE_NPAGE))
+  );
+  assert( iHash>=0 );
+  return iHash;
+}
+
+/*
+** Return the page number associated with frame iFrame in this WAL.
+*/
+static u32 walFramePgno(Wal *pWal, u32 iFrame){
+  int iHash = walFramePage(iFrame);
+  SEH_INJECT_FAULT;
+  if( iHash==0 ){
+    return pWal->apWiData[0][WALINDEX_HDR_SIZE/sizeof(u32) + iFrame - 1];
+  }
+  return pWal->apWiData[iHash][(iFrame-1-HASHTABLE_NPAGE_ONE)%HASHTABLE_NPAGE];
+}
+
+/*
+** Remove entries from the hash table that point to WAL slots greater
+** than pWal->hdr.mxFrame.
+**
+** This function is called whenever pWal->hdr.mxFrame is decreased due
+** to a rollback or savepoint.
+**
+** At most only the hash table containing pWal->hdr.mxFrame needs to be
+** updated.  Any later hash tables will be automatically cleared when
+** pWal->hdr.mxFrame advances to the point where those hash tables are
+** actually needed.
+*/
+static void walCleanupHash(Wal *pWal){
+  WalHashLoc sLoc;                /* Hash table location */
+  int iLimit = 0;                 /* Zero values greater than this */
+  int nByte;                      /* Number of bytes to zero in aPgno[] */
+  int i;                          /* Used to iterate through aHash[] */
+
+  assert( pWal->writeLock );
+  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE-1 );
+  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE );
+  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE+1 );
+
+  if( pWal->hdr.mxFrame==0 ) return;
+
+  /* Obtain pointers to the hash-table and page-number array containing
+  ** the entry that corresponds to frame pWal->hdr.mxFrame. It is guaranteed
+  ** that the page said hash-table and array reside on is already mapped.(1)
+  */
+  assert( pWal->nWiData>walFramePage(pWal->hdr.mxFrame) );
+  assert( pWal->apWiData[walFramePage(pWal->hdr.mxFrame)] );
+  i = walHashGet(pWal, walFramePage(pWal->hdr.mxFrame), &sLoc);
+  if( NEVER(i) ) return; /* Defense-in-depth, in case (1) above is wrong */
+
+  /* Zero all hash-table entries that correspond to frame numbers greater
+  ** than pWal->hdr.mxFrame.
+  */
+  iLimit = pWal->hdr.mxFrame - sLoc.iZero;
+  assert( iLimit>0 );
+  for(i=0; i<HASHTABLE_NSLOT; i++){
+    if( sLoc.aHash[i]>iLimit ){
+      sLoc.aHash[i] = 0;
+    }
+  }
+
+  /* Zero the entries in the aPgno array that correspond to frames with
+  ** frame numbers greater than pWal->hdr.mxFrame.
+  */
+  nByte = (int)((char *)sLoc.aHash - (char *)&sLoc.aPgno[iLimit]);
+  assert( nByte>=0 );
+  memset((void *)&sLoc.aPgno[iLimit], 0, nByte);
+
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+  /* Verify that the every entry in the mapping region is still reachable
+  ** via the hash table even after the cleanup.
+  */
+  if( iLimit ){
+    int j;           /* Loop counter */
+    int iKey;        /* Hash key */
+    for(j=0; j<iLimit; j++){
+      for(iKey=walHash(sLoc.aPgno[j]);sLoc.aHash[iKey];iKey=walNextHash(iKey)){
+        if( sLoc.aHash[iKey]==j+1 ) break;
+      }
+      assert( sLoc.aHash[iKey]==j+1 );
+    }
+  }
+#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
+}
+
+
+/*
+** Set an entry in the wal-index that will map database page number
+** pPage into WAL frame iFrame.
+*/
+static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
+  int rc;                         /* Return code */
+  WalHashLoc sLoc;                /* Wal-index hash table location */
+
+  rc = walHashGet(pWal, walFramePage(iFrame), &sLoc);
+
+  /* Assuming the wal-index file was successfully mapped, populate the
+  ** page number array and hash table entry.
+  */
+  if( rc==SQLITE_OK ){
+    int iKey;                     /* Hash table key */
+    int idx;                      /* Value to write to hash-table slot */
+    int nCollide;                 /* Number of hash collisions */
+
+    idx = iFrame - sLoc.iZero;
+    assert( idx <= HASHTABLE_NSLOT/2 + 1 );
+
+    /* If this is the first entry to be added to this hash-table, zero the
+    ** entire hash table and aPgno[] array before proceeding.
+    */
+    if( idx==1 ){
+      int nByte = (int)((u8*)&sLoc.aHash[HASHTABLE_NSLOT] - (u8*)sLoc.aPgno);
+      assert( nByte>=0 );
+      memset((void*)sLoc.aPgno, 0, nByte);
+    }
+
+    /* If the entry in aPgno[] is already set, then the previous writer
+    ** must have exited unexpectedly in the middle of a transaction (after
+    ** writing one or more dirty pages to the WAL to free up memory).
+    ** Remove the remnants of that writers uncommitted transaction from
+    ** the hash-table before writing any new entries.
+    */
+    if( sLoc.aPgno[idx-1] ){
+      walCleanupHash(pWal);
+      assert( !sLoc.aPgno[idx-1] );
+    }
+
+    /* Write the aPgno[] array entry and the hash-table slot. */
+    nCollide = idx;
+    for(iKey=walHash(iPage); sLoc.aHash[iKey]; iKey=walNextHash(iKey)){
+      if( (nCollide--)==0 ) return SQLITE_CORRUPT_BKPT;
+    }
+    sLoc.aPgno[idx-1] = iPage;
+    AtomicStore(&sLoc.aHash[iKey], (ht_slot)idx);
+
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+    /* Verify that the number of entries in the hash table exactly equals
+    ** the number of entries in the mapping region.
+    */
+    {
+      int i;           /* Loop counter */
+      int nEntry = 0;  /* Number of entries in the hash table */
+      for(i=0; i<HASHTABLE_NSLOT; i++){ if( sLoc.aHash[i] ) nEntry++; }
+      assert( nEntry==idx );
+    }
+
+    /* Verify that the every entry in the mapping region is reachable
+    ** via the hash table.  This turns out to be a really, really expensive
+    ** thing to check, so only do this occasionally - not on every
+    ** iteration.
+    */
+    if( (idx&0x3ff)==0 ){
+      int i;           /* Loop counter */
+      for(i=0; i<idx; i++){
+        for(iKey=walHash(sLoc.aPgno[i]);
+            sLoc.aHash[iKey];
+            iKey=walNextHash(iKey)){
+          if( sLoc.aHash[iKey]==i+1 ) break;
+        }
+        assert( sLoc.aHash[iKey]==i+1 );
+      }
+    }
+#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
+  }
+
+  return rc;
+}
+
+
+/*
+** Recover the wal-index by reading the write-ahead log file.
+**
+** This routine first tries to establish an exclusive lock on the
+** wal-index to prevent other threads/processes from doing anything
+** with the WAL or wal-index while recovery is running.  The
+** WAL_RECOVER_LOCK is also held so that other threads will know
+** that this thread is running recovery.  If unable to establish
+** the necessary locks, this routine returns SQLITE_BUSY.
+*/
+static int walIndexRecover(Wal *pWal){
+  int rc;                         /* Return Code */
+  i64 nSize;                      /* Size of log file */
+  u32 aFrameCksum[2] = {0, 0};
+  int iLock;                      /* Lock offset to lock for checkpoint */
+
+  /* Obtain an exclusive lock on all byte in the locking range not already
+  ** locked by the caller. The caller is guaranteed to have locked the
+  ** WAL_WRITE_LOCK byte, and may have also locked the WAL_CKPT_LOCK byte.
+  ** If successful, the same bytes that are locked here are unlocked before
+  ** this function returns.
+  */
+  assert( pWal->ckptLock==1 || pWal->ckptLock==0 );
+  assert( WAL_ALL_BUT_WRITE==WAL_WRITE_LOCK+1 );
+  assert( WAL_CKPT_LOCK==WAL_ALL_BUT_WRITE );
+  assert( pWal->writeLock );
+  iLock = WAL_ALL_BUT_WRITE + pWal->ckptLock;
+  rc = walLockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
+  if( rc ){
+    return rc;
+  }
+
+  WALTRACE(("WAL%p: recovery begin...\n", pWal));
+
+  memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
+
+  rc = sqlite3OsFileSize(pWal->pWalFd, &nSize);
+  if( rc!=SQLITE_OK ){
+    goto recovery_error;
+  }
+
+  if( nSize>WAL_HDRSIZE ){
+    u8 aBuf[WAL_HDRSIZE];         /* Buffer to load WAL header into */
+    u32 *aPrivate = 0;            /* Heap copy of *-shm hash being populated */
+    u8 *aFrame = 0;               /* Malloc'd buffer to load entire frame */
+    int szFrame;                  /* Number of bytes in buffer aFrame[] */
+    u8 *aData;                    /* Pointer to data part of aFrame buffer */
+    int szPage;                   /* Page size according to the log */
+    u32 magic;                    /* Magic value read from WAL header */
+    u32 version;                  /* Magic value read from WAL header */
+    int isValid;                  /* True if this frame is valid */
+    u32 iPg;                      /* Current 32KB wal-index page */
+    u32 iLastFrame;               /* Last frame in wal, based on nSize alone */
+
+    /* Read in the WAL header. */
+    rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
+    if( rc!=SQLITE_OK ){
+      goto recovery_error;
+    }
+
+    /* If the database page size is not a power of two, or is greater than
+    ** SQLITE_MAX_PAGE_SIZE, conclude that the WAL file contains no valid
+    ** data. Similarly, if the 'magic' value is invalid, ignore the whole
+    ** WAL file.
+    */
+    magic = sqlite3Get4byte(&aBuf[0]);
+    szPage = sqlite3Get4byte(&aBuf[8]);
+    if( (magic&0xFFFFFFFE)!=WAL_MAGIC
+     || szPage&(szPage-1)
+     || szPage>SQLITE_MAX_PAGE_SIZE
+     || szPage<512
+    ){
+      goto finished;
+    }
+    pWal->hdr.bigEndCksum = (u8)(magic&0x00000001);
+    pWal->szPage = szPage;
+    pWal->nCkpt = sqlite3Get4byte(&aBuf[12]);
+    memcpy(&pWal->hdr.aSalt, &aBuf[16], 8);
+
+    /* Verify that the WAL header checksum is correct */
+    walChecksumBytes(pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN,
+        aBuf, WAL_HDRSIZE-2*4, 0, pWal->hdr.aFrameCksum
+    );
+    if( pWal->hdr.aFrameCksum[0]!=sqlite3Get4byte(&aBuf[24])
+     || pWal->hdr.aFrameCksum[1]!=sqlite3Get4byte(&aBuf[28])
+    ){
+      goto finished;
+    }
+
+    /* Verify that the version number on the WAL format is one that
+    ** are able to understand */
+    version = sqlite3Get4byte(&aBuf[4]);
+    if( version!=WAL_MAX_VERSION ){
+      rc = SQLITE_CANTOPEN_BKPT;
+      goto finished;
+    }
+
+    /* Malloc a buffer to read frames into. */
+    szFrame = szPage + WAL_FRAME_HDRSIZE;
+    aFrame = (u8 *)sqlite3_malloc64(szFrame + WALINDEX_PGSZ);
+    SEH_FREE_ON_ERROR(0, aFrame);
+    if( !aFrame ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto recovery_error;
+    }
+    aData = &aFrame[WAL_FRAME_HDRSIZE];
+    aPrivate = (u32*)&aData[szPage];
+
+    /* Read all frames from the log file. */
+    iLastFrame = (nSize - WAL_HDRSIZE) / szFrame;
+    for(iPg=0; iPg<=(u32)walFramePage(iLastFrame); iPg++){
+      u32 *aShare;
+      u32 iFrame;                 /* Index of last frame read */
+      u32 iLast = MIN(iLastFrame, HASHTABLE_NPAGE_ONE+iPg*HASHTABLE_NPAGE);
+      u32 iFirst = 1 + (iPg==0?0:HASHTABLE_NPAGE_ONE+(iPg-1)*HASHTABLE_NPAGE);
+      u32 nHdr, nHdr32;
+      rc = walIndexPage(pWal, iPg, (volatile u32**)&aShare);
+      assert( aShare!=0 || rc!=SQLITE_OK );
+      if( aShare==0 ) break;
+      SEH_SET_ON_ERROR(iPg, aShare);
+      pWal->apWiData[iPg] = aPrivate;
+
+      for(iFrame=iFirst; iFrame<=iLast; iFrame++){
+        i64 iOffset = walFrameOffset(iFrame, szPage);
+        u32 pgno;                 /* Database page number for frame */
+        u32 nTruncate;            /* dbsize field from frame header */
+
+        /* Read and decode the next log frame. */
+        rc = sqlite3OsRead(pWal->pWalFd, aFrame, szFrame, iOffset);
+        if( rc!=SQLITE_OK ) break;
+        isValid = walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame);
+        if( !isValid ) break;
+        rc = walIndexAppend(pWal, iFrame, pgno);
+        if( NEVER(rc!=SQLITE_OK) ) break;
+
+        /* If nTruncate is non-zero, this is a commit record. */
+        if( nTruncate ){
+          pWal->hdr.mxFrame = iFrame;
+          pWal->hdr.nPage = nTruncate;
+          pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
+          testcase( szPage<=32768 );
+          testcase( szPage>=65536 );
+          aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
+          aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
+        }
+      }
+      pWal->apWiData[iPg] = aShare;
+      SEH_SET_ON_ERROR(0,0);
+      nHdr = (iPg==0 ? WALINDEX_HDR_SIZE : 0);
+      nHdr32 = nHdr / sizeof(u32);
+#ifndef SQLITE_SAFER_WALINDEX_RECOVERY
+      /* Memcpy() should work fine here, on all reasonable implementations.
+      ** Technically, memcpy() might change the destination to some
+      ** intermediate value before setting to the final value, and that might
+      ** cause a concurrent reader to malfunction.  Memcpy() is allowed to
+      ** do that, according to the spec, but no memcpy() implementation that
+      ** we know of actually does that, which is why we say that memcpy()
+      ** is safe for this.  Memcpy() is certainly a lot faster.
+      */
+      memcpy(&aShare[nHdr32], &aPrivate[nHdr32], WALINDEX_PGSZ-nHdr);
+#else
+      /* In the event that some platform is found for which memcpy()
+      ** changes the destination to some intermediate value before
+      ** setting the final value, this alternative copy routine is
+      ** provided.
+      */
+      {
+        int i;
+        for(i=nHdr32; i<WALINDEX_PGSZ/sizeof(u32); i++){
+          if( aShare[i]!=aPrivate[i] ){
+            /* Atomic memory operations are not required here because if
+            ** the value needs to be changed, that means it is not being
+            ** accessed concurrently. */
+            aShare[i] = aPrivate[i];
+          }
+        }
+      }
+#endif
+      SEH_INJECT_FAULT;
+      if( iFrame<=iLast ) break;
+    }
+
+    SEH_FREE_ON_ERROR(aFrame, 0);
+    sqlite3_free(aFrame);
+  }
+
+finished:
+  if( rc==SQLITE_OK ){
+    volatile WalCkptInfo *pInfo;
+    int i;
+    pWal->hdr.aFrameCksum[0] = aFrameCksum[0];
+    pWal->hdr.aFrameCksum[1] = aFrameCksum[1];
+    walIndexWriteHdr(pWal);
+
+    /* Reset the checkpoint-header. This is safe because this thread is
+    ** currently holding locks that exclude all other writers and
+    ** checkpointers. Then set the values of read-mark slots 1 through N.
+    */
+    pInfo = walCkptInfo(pWal);
+    pInfo->nBackfill = 0;
+    pInfo->nBackfillAttempted = pWal->hdr.mxFrame;
+    pInfo->aReadMark[0] = 0;
+    for(i=1; i<WAL_NREADER; i++){
+      rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
+      if( rc==SQLITE_OK ){
+        if( i==1 && pWal->hdr.mxFrame ){
+          pInfo->aReadMark[i] = pWal->hdr.mxFrame;
+        }else{
+          pInfo->aReadMark[i] = READMARK_NOT_USED;
+        }
+        SEH_INJECT_FAULT;
+        walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
+      }else if( rc!=SQLITE_BUSY ){
+        goto recovery_error;
+      }
+    }
+
+    /* If more than one frame was recovered from the log file, report an
+    ** event via sqlite3_log(). This is to help with identifying performance
+    ** problems caused by applications routinely shutting down without
+    ** checkpointing the log file.
+    */
+    if( pWal->hdr.nPage ){
+      sqlite3_log(SQLITE_NOTICE_RECOVER_WAL,
+          "recovered %d frames from WAL file %s",
+          pWal->hdr.mxFrame, pWal->zWalName
+      );
+    }
+  }
+
+recovery_error:
+  WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
+  walUnlockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
+  return rc;
+}
+
+/*
+** Close an open wal-index.
+*/
+static void walIndexClose(Wal *pWal, int isDelete){
+  if( pWal->exclusiveMode==WAL_HEAPMEMORY_MODE || pWal->bShmUnreliable ){
+    int i;
+    for(i=0; i<pWal->nWiData; i++){
+      sqlite3_free((void *)pWal->apWiData[i]);
+      pWal->apWiData[i] = 0;
+    }
+  }
+  if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
+    sqlite3OsShmUnmap(pWal->pDbFd, isDelete);
+  }
+}
+
+/*
+** Open a connection to the WAL file zWalName. The database file must
+** already be opened on connection pDbFd. The buffer that zWalName points
+** to must remain valid for the lifetime of the returned Wal* handle.
+**
+** A SHARED lock should be held on the database file when this function
+** is called. The purpose of this SHARED lock is to prevent any other
+** client from unlinking the WAL or wal-index file. If another process
+** were to do this just after this client opened one of these files, the
+** system would be badly broken.
+**
+** If the log file is successfully opened, SQLITE_OK is returned and
+** *ppWal is set to point to a new WAL handle. If an error occurs,
+** an SQLite error code is returned and *ppWal is left unmodified.
+*/
+SQLITE_PRIVATE int sqlite3WalOpen(
+  sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
+  sqlite3_file *pDbFd,            /* The open database file */
+  const char *zWalName,           /* Name of the WAL file */
+  int bNoShm,                     /* True to run in heap-memory mode */
+  i64 mxWalSize,                  /* Truncate WAL to this size on reset */
+  Wal **ppWal                     /* OUT: Allocated Wal handle */
+){
+  int rc;                         /* Return Code */
+  Wal *pRet;                      /* Object to allocate and return */
+  int flags;                      /* Flags passed to OsOpen() */
+
+  assert( zWalName && zWalName[0] );
+  assert( pDbFd );
+
+  /* Verify the values of various constants.  Any changes to the values
+  ** of these constants would result in an incompatible on-disk format
+  ** for the -shm file.  Any change that causes one of these asserts to
+  ** fail is a backward compatibility problem, even if the change otherwise
+  ** works.
+  **
+  ** This table also serves as a helpful cross-reference when trying to
+  ** interpret hex dumps of the -shm file.
+  */
+  assert(    48 ==  sizeof(WalIndexHdr)  );
+  assert(    40 ==  sizeof(WalCkptInfo)  );
+  assert(   120 ==  WALINDEX_LOCK_OFFSET );
+  assert(   136 ==  WALINDEX_HDR_SIZE    );
+  assert(  4096 ==  HASHTABLE_NPAGE      );
+  assert(  4062 ==  HASHTABLE_NPAGE_ONE  );
+  assert(  8192 ==  HASHTABLE_NSLOT      );
+  assert(   383 ==  HASHTABLE_HASH_1     );
+  assert( 32768 ==  WALINDEX_PGSZ        );
+  assert(     8 ==  SQLITE_SHM_NLOCK     );
+  assert(     5 ==  WAL_NREADER          );
+  assert(    24 ==  WAL_FRAME_HDRSIZE    );
+  assert(    32 ==  WAL_HDRSIZE          );
+  assert(   120 ==  WALINDEX_LOCK_OFFSET + WAL_WRITE_LOCK   );
+  assert(   121 ==  WALINDEX_LOCK_OFFSET + WAL_CKPT_LOCK    );
+  assert(   122 ==  WALINDEX_LOCK_OFFSET + WAL_RECOVER_LOCK );
+  assert(   123 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(0) );
+  assert(   124 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(1) );
+  assert(   125 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(2) );
+  assert(   126 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(3) );
+  assert(   127 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(4) );
+
+  /* In the amalgamation, the os_unix.c and os_win.c source files come before
+  ** this source file.  Verify that the #defines of the locking byte offsets
+  ** in os_unix.c and os_win.c agree with the WALINDEX_LOCK_OFFSET value.
+  ** For that matter, if the lock offset ever changes from its initial design
+  ** value of 120, we need to know that so there is an assert() to check it.
+  */
+#ifdef WIN_SHM_BASE
+  assert( WIN_SHM_BASE==WALINDEX_LOCK_OFFSET );
+#endif
+#ifdef UNIX_SHM_BASE
+  assert( UNIX_SHM_BASE==WALINDEX_LOCK_OFFSET );
+#endif
+
+
+  /* Allocate an instance of struct Wal to return. */
+  *ppWal = 0;
+  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile);
+  if( !pRet ){
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  pRet->pVfs = pVfs;
+  pRet->pWalFd = (sqlite3_file *)&pRet[1];
+  pRet->pDbFd = pDbFd;
+  pRet->readLock = -1;
+  pRet->mxWalSize = mxWalSize;
+  pRet->zWalName = zWalName;
+  pRet->syncHeader = 1;
+  pRet->padToSectorBoundary = 1;
+  pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE);
+
+  /* Open file handle on the write-ahead log file. */
+  flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
+  rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags);
+  if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){
+    pRet->readOnly = WAL_RDONLY;
+  }
+
+  if( rc!=SQLITE_OK ){
+    walIndexClose(pRet, 0);
+    sqlite3OsClose(pRet->pWalFd);
+    sqlite3_free(pRet);
+  }else{
+    int iDC = sqlite3OsDeviceCharacteristics(pDbFd);
+    if( iDC & SQLITE_IOCAP_SEQUENTIAL ){ pRet->syncHeader = 0; }
+    if( iDC & SQLITE_IOCAP_POWERSAFE_OVERWRITE ){
+      pRet->padToSectorBoundary = 0;
+    }
+    *ppWal = pRet;
+    WALTRACE(("WAL%d: opened\n", pRet));
+  }
+  return rc;
+}
+
+/*
+** Change the size to which the WAL file is truncated on each reset.
+*/
+SQLITE_PRIVATE void sqlite3WalLimit(Wal *pWal, i64 iLimit){
+  if( pWal ) pWal->mxWalSize = iLimit;
+}
+
+/*
+** Find the smallest page number out of all pages held in the WAL that
+** has not been returned by any prior invocation of this method on the
+** same WalIterator object.   Write into *piFrame the frame index where
+** that page was last written into the WAL.  Write into *piPage the page
+** number.
+**
+** Return 0 on success.  If there are no pages in the WAL with a page
+** number larger than *piPage, then return 1.
+*/
+static int walIteratorNext(
+  WalIterator *p,               /* Iterator */
+  u32 *piPage,                  /* OUT: The page number of the next page */
+  u32 *piFrame                  /* OUT: Wal frame index of next page */
+){
+  u32 iMin;                     /* Result pgno must be greater than iMin */
+  u32 iRet = 0xFFFFFFFF;        /* 0xffffffff is never a valid page number */
+  int i;                        /* For looping through segments */
+
+  iMin = p->iPrior;
+  assert( iMin<0xffffffff );
+  for(i=p->nSegment-1; i>=0; i--){
+    struct WalSegment *pSegment = &p->aSegment[i];
+    while( pSegment->iNext<pSegment->nEntry ){
+      u32 iPg = pSegment->aPgno[pSegment->aIndex[pSegment->iNext]];
+      if( iPg>iMin ){
+        if( iPg<iRet ){
+          iRet = iPg;
+          *piFrame = pSegment->iZero + pSegment->aIndex[pSegment->iNext];
+        }
+        break;
+      }
+      pSegment->iNext++;
+    }
+  }
+
+  *piPage = p->iPrior = iRet;
+  return (iRet==0xFFFFFFFF);
+}
+
+/*
+** This function merges two sorted lists into a single sorted list.
+**
+** aLeft[] and aRight[] are arrays of indices.  The sort key is
+** aContent[aLeft[]] and aContent[aRight[]].  Upon entry, the following
+** is guaranteed for all J<K:
+**
+**        aContent[aLeft[J]] < aContent[aLeft[K]]
+**        aContent[aRight[J]] < aContent[aRight[K]]
+**
+** This routine overwrites aRight[] with a new (probably longer) sequence
+** of indices such that the aRight[] contains every index that appears in
+** either aLeft[] or the old aRight[] and such that the second condition
+** above is still met.
+**
+** The aContent[aLeft[X]] values will be unique for all X.  And the
+** aContent[aRight[X]] values will be unique too.  But there might be
+** one or more combinations of X and Y such that
+**
+**      aLeft[X]!=aRight[Y]  &&  aContent[aLeft[X]] == aContent[aRight[Y]]
+**
+** When that happens, omit the aLeft[X] and use the aRight[Y] index.
+*/
+static void walMerge(
+  const u32 *aContent,            /* Pages in wal - keys for the sort */
+  ht_slot *aLeft,                 /* IN: Left hand input list */
+  int nLeft,                      /* IN: Elements in array *paLeft */
+  ht_slot **paRight,              /* IN/OUT: Right hand input list */
+  int *pnRight,                   /* IN/OUT: Elements in *paRight */
+  ht_slot *aTmp                   /* Temporary buffer */
+){
+  int iLeft = 0;                  /* Current index in aLeft */
+  int iRight = 0;                 /* Current index in aRight */
+  int iOut = 0;                   /* Current index in output buffer */
+  int nRight = *pnRight;
+  ht_slot *aRight = *paRight;
+
+  assert( nLeft>0 && nRight>0 );
+  while( iRight<nRight || iLeft<nLeft ){
+    ht_slot logpage;
+    Pgno dbpage;
+
+    if( (iLeft<nLeft)
+     && (iRight>=nRight || aContent[aLeft[iLeft]]<aContent[aRight[iRight]])
+    ){
+      logpage = aLeft[iLeft++];
+    }else{
+      logpage = aRight[iRight++];
+    }
+    dbpage = aContent[logpage];
+
+    aTmp[iOut++] = logpage;
+    if( iLeft<nLeft && aContent[aLeft[iLeft]]==dbpage ) iLeft++;
+
+    assert( iLeft>=nLeft || aContent[aLeft[iLeft]]>dbpage );
+    assert( iRight>=nRight || aContent[aRight[iRight]]>dbpage );
+  }
+
+  *paRight = aLeft;
+  *pnRight = iOut;
+  memcpy(aLeft, aTmp, sizeof(aTmp[0])*iOut);
+}
+
+/*
+** Sort the elements in list aList using aContent[] as the sort key.
+** Remove elements with duplicate keys, preferring to keep the
+** larger aList[] values.
+**
+** The aList[] entries are indices into aContent[].  The values in
+** aList[] are to be sorted so that for all J<K:
+**
+**      aContent[aList[J]] < aContent[aList[K]]
+**
+** For any X and Y such that
+**
+**      aContent[aList[X]] == aContent[aList[Y]]
+**
+** Keep the larger of the two values aList[X] and aList[Y] and discard
+** the smaller.
+*/
+static void walMergesort(
+  const u32 *aContent,            /* Pages in wal */
+  ht_slot *aBuffer,               /* Buffer of at least *pnList items to use */
+  ht_slot *aList,                 /* IN/OUT: List to sort */
+  int *pnList                     /* IN/OUT: Number of elements in aList[] */
+){
+  struct Sublist {
+    int nList;                    /* Number of elements in aList */
+    ht_slot *aList;               /* Pointer to sub-list content */
+  };
+
+  const int nList = *pnList;      /* Size of input list */
+  int nMerge = 0;                 /* Number of elements in list aMerge */
+  ht_slot *aMerge = 0;            /* List to be merged */
+  int iList;                      /* Index into input list */
+  u32 iSub = 0;                   /* Index into aSub array */
+  struct Sublist aSub[13];        /* Array of sub-lists */
+
+  memset(aSub, 0, sizeof(aSub));
+  assert( nList<=HASHTABLE_NPAGE && nList>0 );
+  assert( HASHTABLE_NPAGE==(1<<(ArraySize(aSub)-1)) );
+
+  for(iList=0; iList<nList; iList++){
+    nMerge = 1;
+    aMerge = &aList[iList];
+    for(iSub=0; iList & (1<<iSub); iSub++){
+      struct Sublist *p;
+      assert( iSub<ArraySize(aSub) );
+      p = &aSub[iSub];
+      assert( p->aList && p->nList<=(1<<iSub) );
+      assert( p->aList==&aList[iList&~((2<<iSub)-1)] );
+      walMerge(aContent, p->aList, p->nList, &aMerge, &nMerge, aBuffer);
+    }
+    aSub[iSub].aList = aMerge;
+    aSub[iSub].nList = nMerge;
+  }
+
+  for(iSub++; iSub<ArraySize(aSub); iSub++){
+    if( nList & (1<<iSub) ){
+      struct Sublist *p;
+      assert( iSub<ArraySize(aSub) );
+      p = &aSub[iSub];
+      assert( p->nList<=(1<<iSub) );
+      assert( p->aList==&aList[nList&~((2<<iSub)-1)] );
+      walMerge(aContent, p->aList, p->nList, &aMerge, &nMerge, aBuffer);
+    }
+  }
+  assert( aMerge==aList );
+  *pnList = nMerge;
+
+#ifdef SQLITE_DEBUG
+  {
+    int i;
+    for(i=1; i<*pnList; i++){
+      assert( aContent[aList[i]] > aContent[aList[i-1]] );
+    }
+  }
+#endif
+}
+
+/*
+** Free an iterator allocated by walIteratorInit().
+*/
+static void walIteratorFree(WalIterator *p){
+  sqlite3_free(p);
+}
+
+/*
+** Construct a WalInterator object that can be used to loop over all
+** pages in the WAL following frame nBackfill in ascending order. Frames
+** nBackfill or earlier may be included - excluding them is an optimization
+** only. The caller must hold the checkpoint lock.
+**
+** On success, make *pp point to the newly allocated WalInterator object
+** return SQLITE_OK. Otherwise, return an error code. If this routine
+** returns an error, the value of *pp is undefined.
+**
+** The calling routine should invoke walIteratorFree() to destroy the
+** WalIterator object when it has finished with it.
+*/
+static int walIteratorInit(Wal *pWal, u32 nBackfill, WalIterator **pp){
+  WalIterator *p;                 /* Return value */
+  int nSegment;                   /* Number of segments to merge */
+  u32 iLast;                      /* Last frame in log */
+  sqlite3_int64 nByte;            /* Number of bytes to allocate */
+  int i;                          /* Iterator variable */
+  ht_slot *aTmp;                  /* Temp space used by merge-sort */
+  int rc = SQLITE_OK;             /* Return Code */
+
+  /* This routine only runs while holding the checkpoint lock. And
+  ** it only runs if there is actually content in the log (mxFrame>0).
+  */
+  assert( pWal->ckptLock && pWal->hdr.mxFrame>0 );
+  iLast = pWal->hdr.mxFrame;
+
+  /* Allocate space for the WalIterator object. */
+  nSegment = walFramePage(iLast) + 1;
+  nByte = sizeof(WalIterator)
+        + (nSegment-1)*sizeof(struct WalSegment)
+        + iLast*sizeof(ht_slot);
+  p = (WalIterator *)sqlite3_malloc64(nByte
+      + sizeof(ht_slot) * (iLast>HASHTABLE_NPAGE?HASHTABLE_NPAGE:iLast)
+  );
+  if( !p ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  memset(p, 0, nByte);
+  p->nSegment = nSegment;
+  aTmp = (ht_slot*)&(((u8*)p)[nByte]);
+  SEH_FREE_ON_ERROR(0, p);
+  for(i=walFramePage(nBackfill+1); rc==SQLITE_OK && i<nSegment; i++){
+    WalHashLoc sLoc;
+
+    rc = walHashGet(pWal, i, &sLoc);
+    if( rc==SQLITE_OK ){
+      int j;                      /* Counter variable */
+      int nEntry;                 /* Number of entries in this segment */
+      ht_slot *aIndex;            /* Sorted index for this segment */
+
+      if( (i+1)==nSegment ){
+        nEntry = (int)(iLast - sLoc.iZero);
+      }else{
+        nEntry = (int)((u32*)sLoc.aHash - (u32*)sLoc.aPgno);
+      }
+      aIndex = &((ht_slot *)&p->aSegment[p->nSegment])[sLoc.iZero];
+      sLoc.iZero++;
+
+      for(j=0; j<nEntry; j++){
+        aIndex[j] = (ht_slot)j;
+      }
+      walMergesort((u32 *)sLoc.aPgno, aTmp, aIndex, &nEntry);
+      p->aSegment[i].iZero = sLoc.iZero;
+      p->aSegment[i].nEntry = nEntry;
+      p->aSegment[i].aIndex = aIndex;
+      p->aSegment[i].aPgno = (u32 *)sLoc.aPgno;
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    SEH_FREE_ON_ERROR(p, 0);
+    walIteratorFree(p);
+    p = 0;
+  }
+  *pp = p;
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+
+
+/*
+** Attempt to enable blocking locks that block for nMs ms. Return 1 if
+** blocking locks are successfully enabled, or 0 otherwise.
+*/
+static int walEnableBlockingMs(Wal *pWal, int nMs){
+  int rc = sqlite3OsFileControl(
+      pWal->pDbFd, SQLITE_FCNTL_LOCK_TIMEOUT, (void*)&nMs
+  );
+  return (rc==SQLITE_OK);
+}
+
+/*
+** Attempt to enable blocking locks. Blocking locks are enabled only if (a)
+** they are supported by the VFS, and (b) the database handle is configured
+** with a busy-timeout. Return 1 if blocking locks are successfully enabled,
+** or 0 otherwise.
+*/
+static int walEnableBlocking(Wal *pWal){
+  int res = 0;
+  if( pWal->db ){
+    int tmout = pWal->db->busyTimeout;
+    if( tmout ){
+      res = walEnableBlockingMs(pWal, tmout);
+    }
+  }
+  return res;
+}
+
+/*
+** Disable blocking locks.
+*/
+static void walDisableBlocking(Wal *pWal){
+  int tmout = 0;
+  sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_LOCK_TIMEOUT, (void*)&tmout);
+}
+
+/*
+** If parameter bLock is true, attempt to enable blocking locks, take
+** the WRITER lock, and then disable blocking locks. If blocking locks
+** cannot be enabled, no attempt to obtain the WRITER lock is made. Return
+** an SQLite error code if an error occurs, or SQLITE_OK otherwise. It is not
+** an error if blocking locks can not be enabled.
+**
+** If the bLock parameter is false and the WRITER lock is held, release it.
+*/
+SQLITE_PRIVATE int sqlite3WalWriteLock(Wal *pWal, int bLock){
+  int rc = SQLITE_OK;
+  assert( pWal->readLock<0 || bLock==0 );
+  if( bLock ){
+    assert( pWal->db );
+    if( walEnableBlocking(pWal) ){
+      rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1);
+      if( rc==SQLITE_OK ){
+        pWal->writeLock = 1;
+      }
+      walDisableBlocking(pWal);
+    }
+  }else if( pWal->writeLock ){
+    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+    pWal->writeLock = 0;
+  }
+  return rc;
+}
+
+/*
+** Set the database handle used to determine if blocking locks are required.
+*/
+SQLITE_PRIVATE void sqlite3WalDb(Wal *pWal, sqlite3 *db){
+  pWal->db = db;
+}
+
+#else
+# define walEnableBlocking(x) 0
+# define walDisableBlocking(x)
+# define walEnableBlockingMs(pWal, ms) 0
+# define sqlite3WalDb(pWal, db)
+#endif   /* ifdef SQLITE_ENABLE_SETLK_TIMEOUT */
+
+
+/*
+** Attempt to obtain the exclusive WAL lock defined by parameters lockIdx and
+** n. If the attempt fails and parameter xBusy is not NULL, then it is a
+** busy-handler function. Invoke it and retry the lock until either the
+** lock is successfully obtained or the busy-handler returns 0.
+*/
+static int walBusyLock(
+  Wal *pWal,                      /* WAL connection */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int lockIdx,                    /* Offset of first byte to lock */
+  int n                           /* Number of bytes to lock */
+){
+  int rc;
+  do {
+    rc = walLockExclusive(pWal, lockIdx, n);
+  }while( xBusy && rc==SQLITE_BUSY && xBusy(pBusyArg) );
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  if( rc==SQLITE_BUSY_TIMEOUT ){
+    walDisableBlocking(pWal);
+    rc = SQLITE_BUSY;
+  }
+#endif
+  return rc;
+}
+
+/*
+** The cache of the wal-index header must be valid to call this function.
+** Return the page-size in bytes used by the database.
+*/
+static int walPagesize(Wal *pWal){
+  return (pWal->hdr.szPage&0xfe00) + ((pWal->hdr.szPage&0x0001)<<16);
+}
+
+/*
+** The following is guaranteed when this function is called:
+**
+**   a) the WRITER lock is held,
+**   b) the entire log file has been checkpointed, and
+**   c) any existing readers are reading exclusively from the database
+**      file - there are no readers that may attempt to read a frame from
+**      the log file.
+**
+** This function updates the shared-memory structures so that the next
+** client to write to the database (which may be this one) does so by
+** writing frames into the start of the log file.
+**
+** The value of parameter salt1 is used as the aSalt[1] value in the
+** new wal-index header. It should be passed a pseudo-random value (i.e.
+** one obtained from sqlite3_randomness()).
+*/
+static void walRestartHdr(Wal *pWal, u32 salt1){
+  volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
+  int i;                          /* Loop counter */
+  u32 *aSalt = pWal->hdr.aSalt;   /* Big-endian salt values */
+  pWal->nCkpt++;
+  pWal->hdr.mxFrame = 0;
+  sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
+  memcpy(&pWal->hdr.aSalt[1], &salt1, 4);
+  walIndexWriteHdr(pWal);
+  AtomicStore(&pInfo->nBackfill, 0);
+  pInfo->nBackfillAttempted = 0;
+  pInfo->aReadMark[1] = 0;
+  for(i=2; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
+  assert( pInfo->aReadMark[0]==0 );
+}
+
+/*
+** Copy as much content as we can from the WAL back into the database file
+** in response to an sqlite3_wal_checkpoint() request or the equivalent.
+**
+** The amount of information copies from WAL to database might be limited
+** by active readers.  This routine will never overwrite a database page
+** that a concurrent reader might be using.
+**
+** All I/O barrier operations (a.k.a fsyncs) occur in this routine when
+** SQLite is in WAL-mode in synchronous=NORMAL.  That means that if
+** checkpoints are always run by a background thread or background
+** process, foreground threads will never block on a lengthy fsync call.
+**
+** Fsync is called on the WAL before writing content out of the WAL and
+** into the database.  This ensures that if the new content is persistent
+** in the WAL and can be recovered following a power-loss or hard reset.
+**
+** Fsync is also called on the database file if (and only if) the entire
+** WAL content is copied into the database file.  This second fsync makes
+** it safe to delete the WAL since the new content will persist in the
+** database file.
+**
+** This routine uses and updates the nBackfill field of the wal-index header.
+** This is the only routine that will increase the value of nBackfill.
+** (A WAL reset or recovery will revert nBackfill to zero, but not increase
+** its value.)
+**
+** The caller must be holding sufficient locks to ensure that no other
+** checkpoint is running (in any other thread or process) at the same
+** time.
+*/
+static int walCheckpoint(
+  Wal *pWal,                      /* Wal connection */
+  sqlite3 *db,                    /* Check for interrupts on this handle */
+  int eMode,                      /* One of PASSIVE, FULL or RESTART */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags for OsSync() (or 0) */
+  u8 *zBuf                        /* Temporary buffer to use */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int szPage;                     /* Database page-size */
+  WalIterator *pIter = 0;         /* Wal iterator context */
+  u32 iDbpage = 0;                /* Next database page to write */
+  u32 iFrame = 0;                 /* Wal frame containing data for iDbpage */
+  u32 mxSafeFrame;                /* Max frame that can be backfilled */
+  u32 mxPage;                     /* Max database page to write */
+  int i;                          /* Loop counter */
+  volatile WalCkptInfo *pInfo;    /* The checkpoint status information */
+
+  szPage = walPagesize(pWal);
+  testcase( szPage<=32768 );
+  testcase( szPage>=65536 );
+  pInfo = walCkptInfo(pWal);
+  if( pInfo->nBackfill<pWal->hdr.mxFrame ){
+
+    /* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
+    ** in the SQLITE_CHECKPOINT_PASSIVE mode. */
+    assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );
+
+    /* Compute in mxSafeFrame the index of the last frame of the WAL that is
+    ** safe to write into the database.  Frames beyond mxSafeFrame might
+    ** overwrite database pages that are in use by active readers and thus
+    ** cannot be backfilled from the WAL.
+    */
+    mxSafeFrame = pWal->hdr.mxFrame;
+    mxPage = pWal->hdr.nPage;
+    for(i=1; i<WAL_NREADER; i++){
+      u32 y = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
+      if( mxSafeFrame>y ){
+        assert( y<=pWal->hdr.mxFrame );
+        rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
+        if( rc==SQLITE_OK ){
+          u32 iMark = (i==1 ? mxSafeFrame : READMARK_NOT_USED);
+          AtomicStore(pInfo->aReadMark+i, iMark); SEH_INJECT_FAULT;
+          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
+        }else if( rc==SQLITE_BUSY ){
+          mxSafeFrame = y;
+          xBusy = 0;
+        }else{
+          goto walcheckpoint_out;
+        }
+      }
+    }
+
+    /* Allocate the iterator */
+    if( pInfo->nBackfill<mxSafeFrame ){
+      rc = walIteratorInit(pWal, pInfo->nBackfill, &pIter);
+      assert( rc==SQLITE_OK || pIter==0 );
+    }
+
+    if( pIter
+     && (rc = walBusyLock(pWal,xBusy,pBusyArg,WAL_READ_LOCK(0),1))==SQLITE_OK
+    ){
+      u32 nBackfill = pInfo->nBackfill;
+      pInfo->nBackfillAttempted = mxSafeFrame; SEH_INJECT_FAULT;
+
+      /* Sync the WAL to disk */
+      rc = sqlite3OsSync(pWal->pWalFd, CKPT_SYNC_FLAGS(sync_flags));
+
+      /* If the database may grow as a result of this checkpoint, hint
+      ** about the eventual size of the db file to the VFS layer.
+      */
+      if( rc==SQLITE_OK ){
+        i64 nReq = ((i64)mxPage * szPage);
+        i64 nSize;                    /* Current size of database file */
+        sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_CKPT_START, 0);
+        rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
+        if( rc==SQLITE_OK && nSize<nReq ){
+          if( (nSize+65536+(i64)pWal->hdr.mxFrame*szPage)<nReq ){
+            /* If the size of the final database is larger than the current
+            ** database plus the amount of data in the wal file, plus the
+            ** maximum size of the pending-byte page (65536 bytes), then
+            ** must be corruption somewhere.  */
+            rc = SQLITE_CORRUPT_BKPT;
+          }else{
+            sqlite3OsFileControlHint(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT,&nReq);
+          }
+        }
+
+      }
+
+      /* Iterate through the contents of the WAL, copying data to the db file */
+      while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
+        i64 iOffset;
+        assert( walFramePgno(pWal, iFrame)==iDbpage );
+        SEH_INJECT_FAULT;
+        if( AtomicLoad(&db->u1.isInterrupted) ){
+          rc = db->mallocFailed ? SQLITE_NOMEM_BKPT : SQLITE_INTERRUPT;
+          break;
+        }
+        if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ){
+          continue;
+        }
+        iOffset = walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE;
+        /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL file */
+        rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, iOffset);
+        if( rc!=SQLITE_OK ) break;
+        iOffset = (iDbpage-1)*(i64)szPage;
+        testcase( IS_BIG_INT(iOffset) );
+        rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
+        if( rc!=SQLITE_OK ) break;
+      }
+      sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_CKPT_DONE, 0);
+
+      /* If work was actually accomplished... */
+      if( rc==SQLITE_OK ){
+        if( mxSafeFrame==walIndexHdr(pWal)->mxFrame ){
+          i64 szDb = pWal->hdr.nPage*(i64)szPage;
+          testcase( IS_BIG_INT(szDb) );
+          rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3OsSync(pWal->pDbFd, CKPT_SYNC_FLAGS(sync_flags));
+          }
+        }
+        if( rc==SQLITE_OK ){
+          AtomicStore(&pInfo->nBackfill, mxSafeFrame); SEH_INJECT_FAULT;
+        }
+      }
+
+      /* Release the reader lock held while backfilling */
+      walUnlockExclusive(pWal, WAL_READ_LOCK(0), 1);
+    }
+
+    if( rc==SQLITE_BUSY ){
+      /* Reset the return code so as not to report a checkpoint failure
+      ** just because there are active readers.  */
+      rc = SQLITE_OK;
+    }
+  }
+
+  /* If this is an SQLITE_CHECKPOINT_RESTART or TRUNCATE operation, and the
+  ** entire wal file has been copied into the database file, then block
+  ** until all readers have finished using the wal file. This ensures that
+  ** the next process to write to the database restarts the wal file.
+  */
+  if( rc==SQLITE_OK && eMode!=SQLITE_CHECKPOINT_PASSIVE ){
+    assert( pWal->writeLock );
+    SEH_INJECT_FAULT;
+    if( pInfo->nBackfill<pWal->hdr.mxFrame ){
+      rc = SQLITE_BUSY;
+    }else if( eMode>=SQLITE_CHECKPOINT_RESTART ){
+      u32 salt1;
+      sqlite3_randomness(4, &salt1);
+      assert( pInfo->nBackfill==pWal->hdr.mxFrame );
+      rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(1), WAL_NREADER-1);
+      if( rc==SQLITE_OK ){
+        if( eMode==SQLITE_CHECKPOINT_TRUNCATE ){
+          /* IMPLEMENTATION-OF: R-44699-57140 This mode works the same way as
+          ** SQLITE_CHECKPOINT_RESTART with the addition that it also
+          ** truncates the log file to zero bytes just prior to a
+          ** successful return.
+          **
+          ** In theory, it might be safe to do this without updating the
+          ** wal-index header in shared memory, as all subsequent reader or
+          ** writer clients should see that the entire log file has been
+          ** checkpointed and behave accordingly. This seems unsafe though,
+          ** as it would leave the system in a state where the contents of
+          ** the wal-index header do not match the contents of the
+          ** file-system. To avoid this, update the wal-index header to
+          ** indicate that the log file contains zero valid frames.  */
+          walRestartHdr(pWal, salt1);
+          rc = sqlite3OsTruncate(pWal->pWalFd, 0);
+        }
+        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
+      }
+    }
+  }
+
+ walcheckpoint_out:
+  SEH_FREE_ON_ERROR(pIter, 0);
+  walIteratorFree(pIter);
+  return rc;
+}
+
+/*
+** If the WAL file is currently larger than nMax bytes in size, truncate
+** it to exactly nMax bytes. If an error occurs while doing so, ignore it.
+*/
+static void walLimitSize(Wal *pWal, i64 nMax){
+  i64 sz;
+  int rx;
+  sqlite3BeginBenignMalloc();
+  rx = sqlite3OsFileSize(pWal->pWalFd, &sz);
+  if( rx==SQLITE_OK && (sz > nMax ) ){
+    rx = sqlite3OsTruncate(pWal->pWalFd, nMax);
+  }
+  sqlite3EndBenignMalloc();
+  if( rx ){
+    sqlite3_log(rx, "cannot limit WAL size: %s", pWal->zWalName);
+  }
+}
+
+#ifdef SQLITE_USE_SEH
+/*
+** This is the "standard" exception handler used in a few places to handle
+** an exception thrown by reading from the *-shm mapping after it has become
+** invalid in SQLITE_USE_SEH builds. It is used as follows:
+**
+**   SEH_TRY { ... }
+**   SEH_EXCEPT( rc = walHandleException(pWal); )
+**
+** This function does three things:
+**
+**   1) Determines the locks that should be held, based on the contents of
+**      the Wal.readLock, Wal.writeLock and Wal.ckptLock variables. All other
+**      held locks are assumed to be transient locks that would have been
+**      released had the exception not been thrown and are dropped.
+**
+**   2) Frees the pointer at Wal.pFree, if any, using sqlite3_free().
+**
+**   3) Set pWal->apWiData[pWal->iWiPg] to pWal->pWiValue if not NULL
+**
+**   4) Returns SQLITE_IOERR.
+*/
+static int walHandleException(Wal *pWal){
+  if( pWal->exclusiveMode==0 ){
+    static const int S = 1;
+    static const int E = (1<<SQLITE_SHM_NLOCK);
+    int ii;
+    u32 mUnlock = pWal->lockMask & ~(
+        (pWal->readLock<0 ? 0 : (S << WAL_READ_LOCK(pWal->readLock)))
+        | (pWal->writeLock ? (E << WAL_WRITE_LOCK) : 0)
+        | (pWal->ckptLock ? (E << WAL_CKPT_LOCK) : 0)
+        );
+    for(ii=0; ii<SQLITE_SHM_NLOCK; ii++){
+      if( (S<<ii) & mUnlock ) walUnlockShared(pWal, ii);
+      if( (E<<ii) & mUnlock ) walUnlockExclusive(pWal, ii, 1);
+    }
+  }
+  sqlite3_free(pWal->pFree);
+  pWal->pFree = 0;
+  if( pWal->pWiValue ){
+    pWal->apWiData[pWal->iWiPg] = pWal->pWiValue;
+    pWal->pWiValue = 0;
+  }
+  return SQLITE_IOERR_IN_PAGE;
+}
+
+/*
+** Assert that the Wal.lockMask mask, which indicates the locks held
+** by the connection, is consistent with the Wal.readLock, Wal.writeLock
+** and Wal.ckptLock variables. To be used as:
+**
+**   assert( walAssertLockmask(pWal) );
+*/
+static int walAssertLockmask(Wal *pWal){
+  if( pWal->exclusiveMode==0 ){
+    static const int S = 1;
+    static const int E = (1<<SQLITE_SHM_NLOCK);
+    u32 mExpect = (
+        (pWal->readLock<0 ? 0 : (S << WAL_READ_LOCK(pWal->readLock)))
+      | (pWal->writeLock ? (E << WAL_WRITE_LOCK) : 0)
+      | (pWal->ckptLock ? (E << WAL_CKPT_LOCK) : 0)
+#ifdef SQLITE_ENABLE_SNAPSHOT
+      | (pWal->pSnapshot ? (pWal->lockMask & (1 << WAL_CKPT_LOCK)) : 0)
+#endif
+    );
+    assert( mExpect==pWal->lockMask );
+  }
+  return 1;
+}
+
+/*
+** Return and zero the "system error" field set when an
+** EXCEPTION_IN_PAGE_ERROR exception is caught.
+*/
+SQLITE_PRIVATE int sqlite3WalSystemErrno(Wal *pWal){
+  int iRet = 0;
+  if( pWal ){
+    iRet = pWal->iSysErrno;
+    pWal->iSysErrno = 0;
+  }
+  return iRet;
+}
+
+#else
+# define walAssertLockmask(x) 1
+#endif /* ifdef SQLITE_USE_SEH */
+
+/*
+** Close a connection to a log file.
+*/
+SQLITE_PRIVATE int sqlite3WalClose(
+  Wal *pWal,                      /* Wal to close */
+  sqlite3 *db,                    /* For interrupt flag */
+  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */
+  int nBuf,
+  u8 *zBuf                        /* Buffer of at least nBuf bytes */
+){
+  int rc = SQLITE_OK;
+  if( pWal ){
+    int isDelete = 0;             /* True to unlink wal and wal-index files */
+
+    assert( walAssertLockmask(pWal) );
+
+    /* If an EXCLUSIVE lock can be obtained on the database file (using the
+    ** ordinary, rollback-mode locking methods, this guarantees that the
+    ** connection associated with this log file is the only connection to
+    ** the database. In this case checkpoint the database and unlink both
+    ** the wal and wal-index files.
+    **
+    ** The EXCLUSIVE lock is not released before returning.
+    */
+    if( zBuf!=0
+     && SQLITE_OK==(rc = sqlite3OsLock(pWal->pDbFd, SQLITE_LOCK_EXCLUSIVE))
+    ){
+      if( pWal->exclusiveMode==WAL_NORMAL_MODE ){
+        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
+      }
+      rc = sqlite3WalCheckpoint(pWal, db,
+          SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
+      );
+      if( rc==SQLITE_OK ){
+        int bPersist = -1;
+        sqlite3OsFileControlHint(
+            pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist
+        );
+        if( bPersist!=1 ){
+          /* Try to delete the WAL file if the checkpoint completed and
+          ** fsynced (rc==SQLITE_OK) and if we are not in persistent-wal
+          ** mode (!bPersist) */
+          isDelete = 1;
+        }else if( pWal->mxWalSize>=0 ){
+          /* Try to truncate the WAL file to zero bytes if the checkpoint
+          ** completed and fsynced (rc==SQLITE_OK) and we are in persistent
+          ** WAL mode (bPersist) and if the PRAGMA journal_size_limit is a
+          ** non-negative value (pWal->mxWalSize>=0).  Note that we truncate
+          ** to zero bytes as truncating to the journal_size_limit might
+          ** leave a corrupt WAL file on disk. */
+          walLimitSize(pWal, 0);
+        }
+      }
+    }
+
+    walIndexClose(pWal, isDelete);
+    sqlite3OsClose(pWal->pWalFd);
+    if( isDelete ){
+      sqlite3BeginBenignMalloc();
+      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
+      sqlite3EndBenignMalloc();
+    }
+    WALTRACE(("WAL%p: closed\n", pWal));
+    sqlite3_free((void *)pWal->apWiData);
+    sqlite3_free(pWal);
+  }
+  return rc;
+}
+
+/*
+** Try to read the wal-index header.  Return 0 on success and 1 if
+** there is a problem.
+**
+** The wal-index is in shared memory.  Another thread or process might
+** be writing the header at the same time this procedure is trying to
+** read it, which might result in inconsistency.  A dirty read is detected
+** by verifying that both copies of the header are the same and also by
+** a checksum on the header.
+**
+** If and only if the read is consistent and the header is different from
+** pWal->hdr, then pWal->hdr is updated to the content of the new header
+** and *pChanged is set to 1.
+**
+** If the checksum cannot be verified return non-zero. If the header
+** is read successfully and the checksum verified, return zero.
+*/
+static SQLITE_NO_TSAN int walIndexTryHdr(Wal *pWal, int *pChanged){
+  u32 aCksum[2];                  /* Checksum on the header content */
+  WalIndexHdr h1, h2;             /* Two copies of the header content */
+  WalIndexHdr volatile *aHdr;     /* Header in shared memory */
+
+  /* The first page of the wal-index must be mapped at this point. */
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+
+  /* Read the header. This might happen concurrently with a write to the
+  ** same area of shared memory on a different CPU in a SMP,
+  ** meaning it is possible that an inconsistent snapshot is read
+  ** from the file. If this happens, return non-zero.
+  **
+  ** tag-20200519-1:
+  ** There are two copies of the header at the beginning of the wal-index.
+  ** When reading, read [0] first then [1].  Writes are in the reverse order.
+  ** Memory barriers are used to prevent the compiler or the hardware from
+  ** reordering the reads and writes.  TSAN and similar tools can sometimes
+  ** give false-positive warnings about these accesses because the tools do not
+  ** account for the double-read and the memory barrier. The use of mutexes
+  ** here would be problematic as the memory being accessed is potentially
+  ** shared among multiple processes and not all mutex implementations work
+  ** reliably in that environment.
+  */
+  aHdr = walIndexHdr(pWal);
+  memcpy(&h1, (void *)&aHdr[0], sizeof(h1)); /* Possible TSAN false-positive */
+  walShmBarrier(pWal);
+  memcpy(&h2, (void *)&aHdr[1], sizeof(h2));
+
+  if( memcmp(&h1, &h2, sizeof(h1))!=0 ){
+    return 1;   /* Dirty read */
+  }
+  if( h1.isInit==0 ){
+    return 1;   /* Malformed header - probably all zeros */
+  }
+  walChecksumBytes(1, (u8*)&h1, sizeof(h1)-sizeof(h1.aCksum), 0, aCksum);
+  if( aCksum[0]!=h1.aCksum[0] || aCksum[1]!=h1.aCksum[1] ){
+    return 1;   /* Checksum does not match */
+  }
+
+  if( memcmp(&pWal->hdr, &h1, sizeof(WalIndexHdr)) ){
+    *pChanged = 1;
+    memcpy(&pWal->hdr, &h1, sizeof(WalIndexHdr));
+    pWal->szPage = (pWal->hdr.szPage&0xfe00) + ((pWal->hdr.szPage&0x0001)<<16);
+    testcase( pWal->szPage<=32768 );
+    testcase( pWal->szPage>=65536 );
+  }
+
+  /* The header was successfully read. Return zero. */
+  return 0;
+}
+
+/*
+** This is the value that walTryBeginRead returns when it needs to
+** be retried.
+*/
+#define WAL_RETRY  (-1)
+
+/*
+** Read the wal-index header from the wal-index and into pWal->hdr.
+** If the wal-header appears to be corrupt, try to reconstruct the
+** wal-index from the WAL before returning.
+**
+** Set *pChanged to 1 if the wal-index header value in pWal->hdr is
+** changed by this operation.  If pWal->hdr is unchanged, set *pChanged
+** to 0.
+**
+** If the wal-index header is successfully read, return SQLITE_OK.
+** Otherwise an SQLite error code.
+*/
+static int walIndexReadHdr(Wal *pWal, int *pChanged){
+  int rc;                         /* Return code */
+  int badHdr;                     /* True if a header read failed */
+  volatile u32 *page0;            /* Chunk of wal-index containing header */
+
+  /* Ensure that page 0 of the wal-index (the page that contains the
+  ** wal-index header) is mapped. Return early if an error occurs here.
+  */
+  assert( pChanged );
+  rc = walIndexPage(pWal, 0, &page0);
+  if( rc!=SQLITE_OK ){
+    assert( rc!=SQLITE_READONLY ); /* READONLY changed to OK in walIndexPage */
+    if( rc==SQLITE_READONLY_CANTINIT ){
+      /* The SQLITE_READONLY_CANTINIT return means that the shared-memory
+      ** was openable but is not writable, and this thread is unable to
+      ** confirm that another write-capable connection has the shared-memory
+      ** open, and hence the content of the shared-memory is unreliable,
+      ** since the shared-memory might be inconsistent with the WAL file
+      ** and there is no writer on hand to fix it. */
+      assert( page0==0 );
+      assert( pWal->writeLock==0 );
+      assert( pWal->readOnly & WAL_SHM_RDONLY );
+      pWal->bShmUnreliable = 1;
+      pWal->exclusiveMode = WAL_HEAPMEMORY_MODE;
+      *pChanged = 1;
+    }else{
+      return rc; /* Any other non-OK return is just an error */
+    }
+  }else{
+    /* page0 can be NULL if the SHM is zero bytes in size and pWal->writeLock
+    ** is zero, which prevents the SHM from growing */
+    testcase( page0!=0 );
+  }
+  assert( page0!=0 || pWal->writeLock==0 );
+
+  /* If the first page of the wal-index has been mapped, try to read the
+  ** wal-index header immediately, without holding any lock. This usually
+  ** works, but may fail if the wal-index header is corrupt or currently
+  ** being modified by another thread or process.
+  */
+  badHdr = (page0 ? walIndexTryHdr(pWal, pChanged) : 1);
+
+  /* If the first attempt failed, it might have been due to a race
+  ** with a writer.  So get a WRITE lock and try again.
+  */
+  if( badHdr ){
+    if( pWal->bShmUnreliable==0 && (pWal->readOnly & WAL_SHM_RDONLY) ){
+      if( SQLITE_OK==(rc = walLockShared(pWal, WAL_WRITE_LOCK)) ){
+        walUnlockShared(pWal, WAL_WRITE_LOCK);
+        rc = SQLITE_READONLY_RECOVERY;
+      }
+    }else{
+      int bWriteLock = pWal->writeLock;
+      if( bWriteLock
+       || SQLITE_OK==(rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1))
+      ){
+        pWal->writeLock = 1;
+        if( SQLITE_OK==(rc = walIndexPage(pWal, 0, &page0)) ){
+          badHdr = walIndexTryHdr(pWal, pChanged);
+          if( badHdr ){
+            /* If the wal-index header is still malformed even while holding
+            ** a WRITE lock, it can only mean that the header is corrupted and
+            ** needs to be reconstructed.  So run recovery to do exactly that.
+            ** Disable blocking locks first.  */
+            walDisableBlocking(pWal);
+            rc = walIndexRecover(pWal);
+            *pChanged = 1;
+          }
+        }
+        if( bWriteLock==0 ){
+          pWal->writeLock = 0;
+          walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+        }
+      }
+    }
+  }
+
+  /* If the header is read successfully, check the version number to make
+  ** sure the wal-index was not constructed with some future format that
+  ** this version of SQLite cannot understand.
+  */
+  if( badHdr==0 && pWal->hdr.iVersion!=WALINDEX_MAX_VERSION ){
+    rc = SQLITE_CANTOPEN_BKPT;
+  }
+  if( pWal->bShmUnreliable ){
+    if( rc!=SQLITE_OK ){
+      walIndexClose(pWal, 0);
+      pWal->bShmUnreliable = 0;
+      assert( pWal->nWiData>0 && pWal->apWiData[0]==0 );
+      /* walIndexRecover() might have returned SHORT_READ if a concurrent
+      ** writer truncated the WAL out from under it.  If that happens, it
+      ** indicates that a writer has fixed the SHM file for us, so retry */
+      if( rc==SQLITE_IOERR_SHORT_READ ) rc = WAL_RETRY;
+    }
+    pWal->exclusiveMode = WAL_NORMAL_MODE;
+  }
+
+  return rc;
+}
+
+/*
+** Open a transaction in a connection where the shared-memory is read-only
+** and where we cannot verify that there is a separate write-capable connection
+** on hand to keep the shared-memory up-to-date with the WAL file.
+**
+** This can happen, for example, when the shared-memory is implemented by
+** memory-mapping a *-shm file, where a prior writer has shut down and
+** left the *-shm file on disk, and now the present connection is trying
+** to use that database but lacks write permission on the *-shm file.
+** Other scenarios are also possible, depending on the VFS implementation.
+**
+** Precondition:
+**
+**    The *-wal file has been read and an appropriate wal-index has been
+**    constructed in pWal->apWiData[] using heap memory instead of shared
+**    memory.
+**
+** If this function returns SQLITE_OK, then the read transaction has
+** been successfully opened. In this case output variable (*pChanged)
+** is set to true before returning if the caller should discard the
+** contents of the page cache before proceeding. Or, if it returns
+** WAL_RETRY, then the heap memory wal-index has been discarded and
+** the caller should retry opening the read transaction from the
+** beginning (including attempting to map the *-shm file).
+**
+** If an error occurs, an SQLite error code is returned.
+*/
+static int walBeginShmUnreliable(Wal *pWal, int *pChanged){
+  i64 szWal;                      /* Size of wal file on disk in bytes */
+  i64 iOffset;                    /* Current offset when reading wal file */
+  u8 aBuf[WAL_HDRSIZE];           /* Buffer to load WAL header into */
+  u8 *aFrame = 0;                 /* Malloc'd buffer to load entire frame */
+  int szFrame;                    /* Number of bytes in buffer aFrame[] */
+  u8 *aData;                      /* Pointer to data part of aFrame buffer */
+  volatile void *pDummy;          /* Dummy argument for xShmMap */
+  int rc;                         /* Return code */
+  u32 aSaveCksum[2];              /* Saved copy of pWal->hdr.aFrameCksum */
+
+  assert( pWal->bShmUnreliable );
+  assert( pWal->readOnly & WAL_SHM_RDONLY );
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+
+  /* Take WAL_READ_LOCK(0). This has the effect of preventing any
+  ** writers from running a checkpoint, but does not stop them
+  ** from running recovery.  */
+  rc = walLockShared(pWal, WAL_READ_LOCK(0));
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_BUSY ) rc = WAL_RETRY;
+    goto begin_unreliable_shm_out;
+  }
+  pWal->readLock = 0;
+
+  /* Check to see if a separate writer has attached to the shared-memory area,
+  ** thus making the shared-memory "reliable" again.  Do this by invoking
+  ** the xShmMap() routine of the VFS and looking to see if the return
+  ** is SQLITE_READONLY instead of SQLITE_READONLY_CANTINIT.
+  **
+  ** If the shared-memory is now "reliable" return WAL_RETRY, which will
+  ** cause the heap-memory WAL-index to be discarded and the actual
+  ** shared memory to be used in its place.
+  **
+  ** This step is important because, even though this connection is holding
+  ** the WAL_READ_LOCK(0) which prevents a checkpoint, a writer might
+  ** have already checkpointed the WAL file and, while the current
+  ** is active, wrap the WAL and start overwriting frames that this
+  ** process wants to use.
+  **
+  ** Once sqlite3OsShmMap() has been called for an sqlite3_file and has
+  ** returned any SQLITE_READONLY value, it must return only SQLITE_READONLY
+  ** or SQLITE_READONLY_CANTINIT or some error for all subsequent invocations,
+  ** even if some external agent does a "chmod" to make the shared-memory
+  ** writable by us, until sqlite3OsShmUnmap() has been called.
+  ** This is a requirement on the VFS implementation.
+   */
+  rc = sqlite3OsShmMap(pWal->pDbFd, 0, WALINDEX_PGSZ, 0, &pDummy);
+  assert( rc!=SQLITE_OK ); /* SQLITE_OK not possible for read-only connection */
+  if( rc!=SQLITE_READONLY_CANTINIT ){
+    rc = (rc==SQLITE_READONLY ? WAL_RETRY : rc);
+    goto begin_unreliable_shm_out;
+  }
+
+  /* We reach this point only if the real shared-memory is still unreliable.
+  ** Assume the in-memory WAL-index substitute is correct and load it
+  ** into pWal->hdr.
+  */
+  memcpy(&pWal->hdr, (void*)walIndexHdr(pWal), sizeof(WalIndexHdr));
+
+  /* Make sure some writer hasn't come in and changed the WAL file out
+  ** from under us, then disconnected, while we were not looking.
+  */
+  rc = sqlite3OsFileSize(pWal->pWalFd, &szWal);
+  if( rc!=SQLITE_OK ){
+    goto begin_unreliable_shm_out;
+  }
+  if( szWal<WAL_HDRSIZE ){
+    /* If the wal file is too small to contain a wal-header and the
+    ** wal-index header has mxFrame==0, then it must be safe to proceed
+    ** reading the database file only. However, the page cache cannot
+    ** be trusted, as a read/write connection may have connected, written
+    ** the db, run a checkpoint, truncated the wal file and disconnected
+    ** since this client's last read transaction.  */
+    *pChanged = 1;
+    rc = (pWal->hdr.mxFrame==0 ? SQLITE_OK : WAL_RETRY);
+    goto begin_unreliable_shm_out;
+  }
+
+  /* Check the salt keys at the start of the wal file still match. */
+  rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
+  if( rc!=SQLITE_OK ){
+    goto begin_unreliable_shm_out;
+  }
+  if( memcmp(&pWal->hdr.aSalt, &aBuf[16], 8) ){
+    /* Some writer has wrapped the WAL file while we were not looking.
+    ** Return WAL_RETRY which will cause the in-memory WAL-index to be
+    ** rebuilt. */
+    rc = WAL_RETRY;
+    goto begin_unreliable_shm_out;
+  }
+
+  /* Allocate a buffer to read frames into */
+  assert( (pWal->szPage & (pWal->szPage-1))==0 );
+  assert( pWal->szPage>=512 && pWal->szPage<=65536 );
+  szFrame = pWal->szPage + WAL_FRAME_HDRSIZE;
+  aFrame = (u8 *)sqlite3_malloc64(szFrame);
+  if( aFrame==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto begin_unreliable_shm_out;
+  }
+  aData = &aFrame[WAL_FRAME_HDRSIZE];
+
+  /* Check to see if a complete transaction has been appended to the
+  ** wal file since the heap-memory wal-index was created. If so, the
+  ** heap-memory wal-index is discarded and WAL_RETRY returned to
+  ** the caller.  */
+  aSaveCksum[0] = pWal->hdr.aFrameCksum[0];
+  aSaveCksum[1] = pWal->hdr.aFrameCksum[1];
+  for(iOffset=walFrameOffset(pWal->hdr.mxFrame+1, pWal->szPage);
+      iOffset+szFrame<=szWal;
+      iOffset+=szFrame
+  ){
+    u32 pgno;                   /* Database page number for frame */
+    u32 nTruncate;              /* dbsize field from frame header */
+
+    /* Read and decode the next log frame. */
+    rc = sqlite3OsRead(pWal->pWalFd, aFrame, szFrame, iOffset);
+    if( rc!=SQLITE_OK ) break;
+    if( !walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame) ) break;
+
+    /* If nTruncate is non-zero, then a complete transaction has been
+    ** appended to this wal file. Set rc to WAL_RETRY and break out of
+    ** the loop.  */
+    if( nTruncate ){
+      rc = WAL_RETRY;
+      break;
+    }
+  }
+  pWal->hdr.aFrameCksum[0] = aSaveCksum[0];
+  pWal->hdr.aFrameCksum[1] = aSaveCksum[1];
+
+ begin_unreliable_shm_out:
+  sqlite3_free(aFrame);
+  if( rc!=SQLITE_OK ){
+    int i;
+    for(i=0; i<pWal->nWiData; i++){
+      sqlite3_free((void*)pWal->apWiData[i]);
+      pWal->apWiData[i] = 0;
+    }
+    pWal->bShmUnreliable = 0;
+    sqlite3WalEndReadTransaction(pWal);
+    *pChanged = 1;
+  }
+  return rc;
+}
+
+/*
+** The final argument passed to walTryBeginRead() is of type (int*). The
+** caller should invoke walTryBeginRead as follows:
+**
+**   int cnt = 0;
+**   do {
+**     rc = walTryBeginRead(..., &cnt);
+**   }while( rc==WAL_RETRY );
+**
+** The final value of "cnt" is of no use to the caller. It is used by
+** the implementation of walTryBeginRead() as follows:
+**
+**   + Each time walTryBeginRead() is called, it is incremented. Once
+**     it reaches WAL_RETRY_PROTOCOL_LIMIT - indicating that walTryBeginRead()
+**     has many times been invoked and failed with WAL_RETRY - walTryBeginRead()
+**     returns SQLITE_PROTOCOL.
+**
+**   + If SQLITE_ENABLE_SETLK_TIMEOUT is defined and walTryBeginRead() failed
+**     because a blocking lock timed out (SQLITE_BUSY_TIMEOUT from the OS
+**     layer), the WAL_RETRY_BLOCKED_MASK bit is set in "cnt". In this case
+**     the next invocation of walTryBeginRead() may omit an expected call to
+**     sqlite3OsSleep(). There has already been a delay when the previous call
+**     waited on a lock.
+*/
+#define WAL_RETRY_PROTOCOL_LIMIT 100
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+# define WAL_RETRY_BLOCKED_MASK    0x10000000
+#else
+# define WAL_RETRY_BLOCKED_MASK    0
+#endif
+
+/*
+** Attempt to start a read transaction.  This might fail due to a race or
+** other transient condition.  When that happens, it returns WAL_RETRY to
+** indicate to the caller that it is safe to retry immediately.
+**
+** On success return SQLITE_OK.  On a permanent failure (such an
+** I/O error or an SQLITE_BUSY because another process is running
+** recovery) return a positive error code.
+**
+** The useWal parameter is true to force the use of the WAL and disable
+** the case where the WAL is bypassed because it has been completely
+** checkpointed.  If useWal==0 then this routine calls walIndexReadHdr()
+** to make a copy of the wal-index header into pWal->hdr.  If the
+** wal-index header has changed, *pChanged is set to 1 (as an indication
+** to the caller that the local page cache is obsolete and needs to be
+** flushed.)  When useWal==1, the wal-index header is assumed to already
+** be loaded and the pChanged parameter is unused.
+**
+** The caller must set the cnt parameter to the number of prior calls to
+** this routine during the current read attempt that returned WAL_RETRY.
+** This routine will start taking more aggressive measures to clear the
+** race conditions after multiple WAL_RETRY returns, and after an excessive
+** number of errors will ultimately return SQLITE_PROTOCOL.  The
+** SQLITE_PROTOCOL return indicates that some other process has gone rogue
+** and is not honoring the locking protocol.  There is a vanishingly small
+** chance that SQLITE_PROTOCOL could be returned because of a run of really
+** bad luck when there is lots of contention for the wal-index, but that
+** possibility is so small that it can be safely neglected, we believe.
+**
+** On success, this routine obtains a read lock on
+** WAL_READ_LOCK(pWal->readLock).  The pWal->readLock integer is
+** in the range 0 <= pWal->readLock < WAL_NREADER.  If pWal->readLock==(-1)
+** that means the Wal does not hold any read lock.  The reader must not
+** access any database page that is modified by a WAL frame up to and
+** including frame number aReadMark[pWal->readLock].  The reader will
+** use WAL frames up to and including pWal->hdr.mxFrame if pWal->readLock>0
+** Or if pWal->readLock==0, then the reader will ignore the WAL
+** completely and get all content directly from the database file.
+** If the useWal parameter is 1 then the WAL will never be ignored and
+** this routine will always set pWal->readLock>0 on success.
+** When the read transaction is completed, the caller must release the
+** lock on WAL_READ_LOCK(pWal->readLock) and set pWal->readLock to -1.
+**
+** This routine uses the nBackfill and aReadMark[] fields of the header
+** to select a particular WAL_READ_LOCK() that strives to let the
+** checkpoint process do as much work as possible.  This routine might
+** update values of the aReadMark[] array in the header, but if it does
+** so it takes care to hold an exclusive lock on the corresponding
+** WAL_READ_LOCK() while changing values.
+*/
+static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
+  volatile WalCkptInfo *pInfo;    /* Checkpoint information in wal-index */
+  int rc = SQLITE_OK;             /* Return code  */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  int nBlockTmout = 0;
+#endif
+
+  assert( pWal->readLock<0 );     /* Not currently locked */
+
+  /* useWal may only be set for read/write connections */
+  assert( (pWal->readOnly & WAL_SHM_RDONLY)==0 || useWal==0 );
+
+  /* Take steps to avoid spinning forever if there is a protocol error.
+  **
+  ** Circumstances that cause a RETRY should only last for the briefest
+  ** instances of time.  No I/O or other system calls are done while the
+  ** locks are held, so the locks should not be held for very long. But
+  ** if we are unlucky, another process that is holding a lock might get
+  ** paged out or take a page-fault that is time-consuming to resolve,
+  ** during the few nanoseconds that it is holding the lock.  In that case,
+  ** it might take longer than normal for the lock to free.
+  **
+  ** After 5 RETRYs, we begin calling sqlite3OsSleep().  The first few
+  ** calls to sqlite3OsSleep() have a delay of 1 microsecond.  Really this
+  ** is more of a scheduler yield than an actual delay.  But on the 10th
+  ** an subsequent retries, the delays start becoming longer and longer,
+  ** so that on the 100th (and last) RETRY we delay for 323 milliseconds.
+  ** The total delay time before giving up is less than 10 seconds.
+  */
+  (*pCnt)++;
+  if( *pCnt>5 ){
+    int nDelay = 1;                      /* Pause time in microseconds */
+    int cnt = (*pCnt & ~WAL_RETRY_BLOCKED_MASK);
+    if( cnt>WAL_RETRY_PROTOCOL_LIMIT ){
+      VVA_ONLY( pWal->lockError = 1; )
+      return SQLITE_PROTOCOL;
+    }
+    if( *pCnt>=10 ) nDelay = (cnt-9)*(cnt-9)*39;
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    /* In SQLITE_ENABLE_SETLK_TIMEOUT builds, configure the file-descriptor
+    ** to block for locks for approximately nDelay us. This affects three
+    ** locks: (a) the shared lock taken on the DMS slot in os_unix.c (if
+    ** using os_unix.c), (b) the WRITER lock taken in walIndexReadHdr() if the
+    ** first attempted read fails, and (c) the shared lock taken on the
+    ** read-mark.
+    **
+    ** If the previous call failed due to an SQLITE_BUSY_TIMEOUT error,
+    ** then sleep for the minimum of 1us. The previous call already provided
+    ** an extra delay while it was blocking on the lock.
+    */
+    nBlockTmout = (nDelay+998) / 1000;
+    if( !useWal && walEnableBlockingMs(pWal, nBlockTmout) ){
+      if( *pCnt & WAL_RETRY_BLOCKED_MASK ) nDelay = 1;
+    }
+#endif
+    sqlite3OsSleep(pWal->pVfs, nDelay);
+    *pCnt &= ~WAL_RETRY_BLOCKED_MASK;
+  }
+
+  if( !useWal ){
+    assert( rc==SQLITE_OK );
+    if( pWal->bShmUnreliable==0 ){
+      rc = walIndexReadHdr(pWal, pChanged);
+    }
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    walDisableBlocking(pWal);
+    if( rc==SQLITE_BUSY_TIMEOUT ){
+      rc = SQLITE_BUSY;
+      *pCnt |= WAL_RETRY_BLOCKED_MASK;
+    }
+#endif
+    if( rc==SQLITE_BUSY ){
+      /* If there is not a recovery running in another thread or process
+      ** then convert BUSY errors to WAL_RETRY.  If recovery is known to
+      ** be running, convert BUSY to BUSY_RECOVERY.  There is a race here
+      ** which might cause WAL_RETRY to be returned even if BUSY_RECOVERY
+      ** would be technically correct.  But the race is benign since with
+      ** WAL_RETRY this routine will be called again and will probably be
+      ** right on the second iteration.
+      */
+      if( pWal->apWiData[0]==0 ){
+        /* This branch is taken when the xShmMap() method returns SQLITE_BUSY.
+        ** We assume this is a transient condition, so return WAL_RETRY. The
+        ** xShmMap() implementation used by the default unix and win32 VFS
+        ** modules may return SQLITE_BUSY due to a race condition in the
+        ** code that determines whether or not the shared-memory region
+        ** must be zeroed before the requested page is returned.
+        */
+        rc = WAL_RETRY;
+      }else if( SQLITE_OK==(rc = walLockShared(pWal, WAL_RECOVER_LOCK)) ){
+        walUnlockShared(pWal, WAL_RECOVER_LOCK);
+        rc = WAL_RETRY;
+      }else if( rc==SQLITE_BUSY ){
+        rc = SQLITE_BUSY_RECOVERY;
+      }
+    }
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    else if( pWal->bShmUnreliable ){
+      return walBeginShmUnreliable(pWal, pChanged);
+    }
+  }
+
+  assert( pWal->nWiData>0 );
+  assert( pWal->apWiData[0]!=0 );
+  pInfo = walCkptInfo(pWal);
+  SEH_INJECT_FAULT;
+  {
+    u32 mxReadMark;               /* Largest aReadMark[] value */
+    int mxI;                      /* Index of largest aReadMark[] value */
+    int i;                        /* Loop counter */
+    u32 mxFrame;                  /* Wal frame to lock to */
+    if( !useWal && AtomicLoad(&pInfo->nBackfill)==pWal->hdr.mxFrame
+#ifdef SQLITE_ENABLE_SNAPSHOT
+     && ((pWal->bGetSnapshot==0 && pWal->pSnapshot==0) || pWal->hdr.mxFrame==0)
+#endif
+    ){
+      /* The WAL has been completely backfilled (or it is empty).
+      ** and can be safely ignored.
+      */
+      rc = walLockShared(pWal, WAL_READ_LOCK(0));
+      walShmBarrier(pWal);
+      if( rc==SQLITE_OK ){
+        if( memcmp((void *)walIndexHdr(pWal), &pWal->hdr,sizeof(WalIndexHdr)) ){
+          /* It is not safe to allow the reader to continue here if frames
+          ** may have been appended to the log before READ_LOCK(0) was obtained.
+          ** When holding READ_LOCK(0), the reader ignores the entire log file,
+          ** which implies that the database file contains a trustworthy
+          ** snapshot. Since holding READ_LOCK(0) prevents a checkpoint from
+          ** happening, this is usually correct.
+          **
+          ** However, if frames have been appended to the log (or if the log
+          ** is wrapped and written for that matter) before the READ_LOCK(0)
+          ** is obtained, that is not necessarily true. A checkpointer may
+          ** have started to backfill the appended frames but crashed before
+          ** it finished. Leaving a corrupt image in the database file.
+          */
+          walUnlockShared(pWal, WAL_READ_LOCK(0));
+          return WAL_RETRY;
+        }
+        pWal->readLock = 0;
+        return SQLITE_OK;
+      }else if( rc!=SQLITE_BUSY ){
+        return rc;
+      }
+    }
+
+    /* If we get this far, it means that the reader will want to use
+    ** the WAL to get at content from recent commits.  The job now is
+    ** to select one of the aReadMark[] entries that is closest to
+    ** but not exceeding pWal->hdr.mxFrame and lock that entry.
+    */
+    mxReadMark = 0;
+    mxI = 0;
+    mxFrame = pWal->hdr.mxFrame;
+#ifdef SQLITE_ENABLE_SNAPSHOT
+    if( pWal->pSnapshot && pWal->pSnapshot->mxFrame<mxFrame ){
+      mxFrame = pWal->pSnapshot->mxFrame;
+    }
+#endif
+    for(i=1; i<WAL_NREADER; i++){
+      u32 thisMark = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
+      if( mxReadMark<=thisMark && thisMark<=mxFrame ){
+        assert( thisMark!=READMARK_NOT_USED );
+        mxReadMark = thisMark;
+        mxI = i;
+      }
+    }
+    if( (pWal->readOnly & WAL_SHM_RDONLY)==0
+     && (mxReadMark<mxFrame || mxI==0)
+    ){
+      for(i=1; i<WAL_NREADER; i++){
+        rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
+        if( rc==SQLITE_OK ){
+          AtomicStore(pInfo->aReadMark+i,mxFrame);
+          mxReadMark = mxFrame;
+          mxI = i;
+          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
+          break;
+        }else if( rc!=SQLITE_BUSY ){
+          return rc;
+        }
+      }
+    }
+    if( mxI==0 ){
+      assert( rc==SQLITE_BUSY || (pWal->readOnly & WAL_SHM_RDONLY)!=0 );
+      return rc==SQLITE_BUSY ? WAL_RETRY : SQLITE_READONLY_CANTINIT;
+    }
+
+    (void)walEnableBlockingMs(pWal, nBlockTmout);
+    rc = walLockShared(pWal, WAL_READ_LOCK(mxI));
+    walDisableBlocking(pWal);
+    if( rc ){
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+      if( rc==SQLITE_BUSY_TIMEOUT ){
+        *pCnt |= WAL_RETRY_BLOCKED_MASK;
+      }
+#else
+      assert( rc!=SQLITE_BUSY_TIMEOUT );
+#endif
+      assert((rc&0xFF)!=SQLITE_BUSY||rc==SQLITE_BUSY||rc==SQLITE_BUSY_TIMEOUT);
+      return (rc&0xFF)==SQLITE_BUSY ? WAL_RETRY : rc;
+    }
+    /* Now that the read-lock has been obtained, check that neither the
+    ** value in the aReadMark[] array or the contents of the wal-index
+    ** header have changed.
+    **
+    ** It is necessary to check that the wal-index header did not change
+    ** between the time it was read and when the shared-lock was obtained
+    ** on WAL_READ_LOCK(mxI) was obtained to account for the possibility
+    ** that the log file may have been wrapped by a writer, or that frames
+    ** that occur later in the log than pWal->hdr.mxFrame may have been
+    ** copied into the database by a checkpointer. If either of these things
+    ** happened, then reading the database with the current value of
+    ** pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry
+    ** instead.
+    **
+    ** Before checking that the live wal-index header has not changed
+    ** since it was read, set Wal.minFrame to the first frame in the wal
+    ** file that has not yet been checkpointed. This client will not need
+    ** to read any frames earlier than minFrame from the wal file - they
+    ** can be safely read directly from the database file.
+    **
+    ** Because a ShmBarrier() call is made between taking the copy of
+    ** nBackfill and checking that the wal-header in shared-memory still
+    ** matches the one cached in pWal->hdr, it is guaranteed that the
+    ** checkpointer that set nBackfill was not working with a wal-index
+    ** header newer than that cached in pWal->hdr. If it were, that could
+    ** cause a problem. The checkpointer could omit to checkpoint
+    ** a version of page X that lies before pWal->minFrame (call that version
+    ** A) on the basis that there is a newer version (version B) of the same
+    ** page later in the wal file. But if version B happens to like past
+    ** frame pWal->hdr.mxFrame - then the client would incorrectly assume
+    ** that it can read version A from the database file. However, since
+    ** we can guarantee that the checkpointer that set nBackfill could not
+    ** see any pages past pWal->hdr.mxFrame, this problem does not come up.
+    */
+    pWal->minFrame = AtomicLoad(&pInfo->nBackfill)+1; SEH_INJECT_FAULT;
+    walShmBarrier(pWal);
+    if( AtomicLoad(pInfo->aReadMark+mxI)!=mxReadMark
+     || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
+    ){
+      walUnlockShared(pWal, WAL_READ_LOCK(mxI));
+      return WAL_RETRY;
+    }else{
+      assert( mxReadMark<=pWal->hdr.mxFrame );
+      pWal->readLock = (i16)mxI;
+    }
+  }
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+/*
+** This function does the work of sqlite3WalSnapshotRecover().
+*/
+static int walSnapshotRecover(
+  Wal *pWal,                      /* WAL handle */
+  void *pBuf1,                    /* Temp buffer pWal->szPage bytes in size */
+  void *pBuf2                     /* Temp buffer pWal->szPage bytes in size */
+){
+  int szPage = (int)pWal->szPage;
+  int rc;
+  i64 szDb;                       /* Size of db file in bytes */
+
+  rc = sqlite3OsFileSize(pWal->pDbFd, &szDb);
+  if( rc==SQLITE_OK ){
+    volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
+    u32 i = pInfo->nBackfillAttempted;
+    for(i=pInfo->nBackfillAttempted; i>AtomicLoad(&pInfo->nBackfill); i--){
+      WalHashLoc sLoc;          /* Hash table location */
+      u32 pgno;                 /* Page number in db file */
+      i64 iDbOff;               /* Offset of db file entry */
+      i64 iWalOff;              /* Offset of wal file entry */
+
+      rc = walHashGet(pWal, walFramePage(i), &sLoc);
+      if( rc!=SQLITE_OK ) break;
+      assert( i - sLoc.iZero - 1 >=0 );
+      pgno = sLoc.aPgno[i-sLoc.iZero-1];
+      iDbOff = (i64)(pgno-1) * szPage;
+
+      if( iDbOff+szPage<=szDb ){
+        iWalOff = walFrameOffset(i, szPage) + WAL_FRAME_HDRSIZE;
+        rc = sqlite3OsRead(pWal->pWalFd, pBuf1, szPage, iWalOff);
+
+        if( rc==SQLITE_OK ){
+          rc = sqlite3OsRead(pWal->pDbFd, pBuf2, szPage, iDbOff);
+        }
+
+        if( rc!=SQLITE_OK || 0==memcmp(pBuf1, pBuf2, szPage) ){
+          break;
+        }
+      }
+
+      pInfo->nBackfillAttempted = i-1;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Attempt to reduce the value of the WalCkptInfo.nBackfillAttempted
+** variable so that older snapshots can be accessed. To do this, loop
+** through all wal frames from nBackfillAttempted to (nBackfill+1),
+** comparing their content to the corresponding page with the database
+** file, if any. Set nBackfillAttempted to the frame number of the
+** first frame for which the wal file content matches the db file.
+**
+** This is only really safe if the file-system is such that any page
+** writes made by earlier checkpointers were atomic operations, which
+** is not always true. It is also possible that nBackfillAttempted
+** may be left set to a value larger than expected, if a wal frame
+** contains content that duplicate of an earlier version of the same
+** page.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code if an
+** error occurs. It is not an error if nBackfillAttempted cannot be
+** decreased at all.
+*/
+SQLITE_PRIVATE int sqlite3WalSnapshotRecover(Wal *pWal){
+  int rc;
+
+  assert( pWal->readLock>=0 );
+  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
+  if( rc==SQLITE_OK ){
+    void *pBuf1 = sqlite3_malloc(pWal->szPage);
+    void *pBuf2 = sqlite3_malloc(pWal->szPage);
+    if( pBuf1==0 || pBuf2==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pWal->ckptLock = 1;
+      SEH_TRY {
+        rc = walSnapshotRecover(pWal, pBuf1, pBuf2);
+      }
+      SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+      pWal->ckptLock = 0;
+    }
+
+    sqlite3_free(pBuf1);
+    sqlite3_free(pBuf2);
+    walUnlockExclusive(pWal, WAL_CKPT_LOCK, 1);
+  }
+
+  return rc;
+}
+#endif /* SQLITE_ENABLE_SNAPSHOT */
+
+/*
+** This function does the work of sqlite3WalBeginReadTransaction() (see
+** below). That function simply calls this one inside an SEH_TRY{...} block.
+*/
+static int walBeginReadTransaction(Wal *pWal, int *pChanged){
+  int rc;                         /* Return code */
+  int cnt = 0;                    /* Number of TryBeginRead attempts */
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  int ckptLock = 0;
+  int bChanged = 0;
+  WalIndexHdr *pSnapshot = pWal->pSnapshot;
+#endif
+
+  assert( pWal->ckptLock==0 );
+  assert( pWal->nSehTry>0 );
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  if( pSnapshot ){
+    if( memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
+      bChanged = 1;
+    }
+
+    /* It is possible that there is a checkpointer thread running
+    ** concurrent with this code. If this is the case, it may be that the
+    ** checkpointer has already determined that it will checkpoint
+    ** snapshot X, where X is later in the wal file than pSnapshot, but
+    ** has not yet set the pInfo->nBackfillAttempted variable to indicate
+    ** its intent. To avoid the race condition this leads to, ensure that
+    ** there is no checkpointer process by taking a shared CKPT lock
+    ** before checking pInfo->nBackfillAttempted.  */
+    (void)walEnableBlocking(pWal);
+    rc = walLockShared(pWal, WAL_CKPT_LOCK);
+    walDisableBlocking(pWal);
+
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    ckptLock = 1;
+  }
+#endif
+
+  do{
+    rc = walTryBeginRead(pWal, pChanged, 0, &cnt);
+  }while( rc==WAL_RETRY );
+  testcase( (rc&0xff)==SQLITE_BUSY );
+  testcase( (rc&0xff)==SQLITE_IOERR );
+  testcase( rc==SQLITE_PROTOCOL );
+  testcase( rc==SQLITE_OK );
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  if( rc==SQLITE_OK ){
+    if( pSnapshot && memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
+      /* At this point the client has a lock on an aReadMark[] slot holding
+      ** a value equal to or smaller than pSnapshot->mxFrame, but pWal->hdr
+      ** is populated with the wal-index header corresponding to the head
+      ** of the wal file. Verify that pSnapshot is still valid before
+      ** continuing.  Reasons why pSnapshot might no longer be valid:
+      **
+      **    (1)  The WAL file has been reset since the snapshot was taken.
+      **         In this case, the salt will have changed.
+      **
+      **    (2)  A checkpoint as been attempted that wrote frames past
+      **         pSnapshot->mxFrame into the database file.  Note that the
+      **         checkpoint need not have completed for this to cause problems.
+      */
+      volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
+
+      assert( pWal->readLock>0 || pWal->hdr.mxFrame==0 );
+      assert( pInfo->aReadMark[pWal->readLock]<=pSnapshot->mxFrame );
+
+      /* Check that the wal file has not been wrapped. Assuming that it has
+      ** not, also check that no checkpointer has attempted to checkpoint any
+      ** frames beyond pSnapshot->mxFrame. If either of these conditions are
+      ** true, return SQLITE_ERROR_SNAPSHOT. Otherwise, overwrite pWal->hdr
+      ** with *pSnapshot and set *pChanged as appropriate for opening the
+      ** snapshot.  */
+      if( !memcmp(pSnapshot->aSalt, pWal->hdr.aSalt, sizeof(pWal->hdr.aSalt))
+       && pSnapshot->mxFrame>=pInfo->nBackfillAttempted
+      ){
+        assert( pWal->readLock>0 );
+        memcpy(&pWal->hdr, pSnapshot, sizeof(WalIndexHdr));
+        *pChanged = bChanged;
+      }else{
+        rc = SQLITE_ERROR_SNAPSHOT;
+      }
+
+      /* A client using a non-current snapshot may not ignore any frames
+      ** from the start of the wal file. This is because, for a system
+      ** where (minFrame < iSnapshot < maxFrame), a checkpointer may
+      ** have omitted to checkpoint a frame earlier than minFrame in
+      ** the file because there exists a frame after iSnapshot that
+      ** is the same database page.  */
+      pWal->minFrame = 1;
+
+      if( rc!=SQLITE_OK ){
+        sqlite3WalEndReadTransaction(pWal);
+      }
+    }
+  }
+
+  /* Release the shared CKPT lock obtained above. */
+  if( ckptLock ){
+    assert( pSnapshot );
+    walUnlockShared(pWal, WAL_CKPT_LOCK);
+  }
+#endif
+  return rc;
+}
+
+/*
+** Begin a read transaction on the database.
+**
+** This routine used to be called sqlite3OpenSnapshot() and with good reason:
+** it takes a snapshot of the state of the WAL and wal-index for the current
+** instant in time.  The current thread will continue to use this snapshot.
+** Other threads might append new content to the WAL and wal-index but
+** that extra content is ignored by the current thread.
+**
+** If the database contents have changes since the previous read
+** transaction, then *pChanged is set to 1 before returning.  The
+** Pager layer will use this to know that its cache is stale and
+** needs to be flushed.
+*/
+SQLITE_PRIVATE int sqlite3WalBeginReadTransaction(Wal *pWal, int *pChanged){
+  int rc;
+  SEH_TRY {
+    rc = walBeginReadTransaction(pWal, pChanged);
+  }
+  SEH_EXCEPT( rc = walHandleException(pWal); )
+  return rc;
+}
+
+/*
+** Finish with a read transaction.  All this does is release the
+** read-lock.
+*/
+SQLITE_PRIVATE void sqlite3WalEndReadTransaction(Wal *pWal){
+  sqlite3WalEndWriteTransaction(pWal);
+  if( pWal->readLock>=0 ){
+    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
+    pWal->readLock = -1;
+  }
+}
+
+/*
+** Search the wal file for page pgno. If found, set *piRead to the frame that
+** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
+** to zero.
+**
+** Return SQLITE_OK if successful, or an error code if an error occurs. If an
+** error does occur, the final value of *piRead is undefined.
+*/
+static int walFindFrame(
+  Wal *pWal,                      /* WAL handle */
+  Pgno pgno,                      /* Database page number to read data for */
+  u32 *piRead                     /* OUT: Frame number (or zero) */
+){
+  u32 iRead = 0;                  /* If !=0, WAL frame to return data from */
+  u32 iLast = pWal->hdr.mxFrame;  /* Last page in WAL for this reader */
+  int iHash;                      /* Used to loop through N hash tables */
+  int iMinHash;
+
+  /* This routine is only be called from within a read transaction. */
+  assert( pWal->readLock>=0 || pWal->lockError );
+
+  /* If the "last page" field of the wal-index header snapshot is 0, then
+  ** no data will be read from the wal under any circumstances. Return early
+  ** in this case as an optimization.  Likewise, if pWal->readLock==0,
+  ** then the WAL is ignored by the reader so return early, as if the
+  ** WAL were empty.
+  */
+  if( iLast==0 || (pWal->readLock==0 && pWal->bShmUnreliable==0) ){
+    *piRead = 0;
+    return SQLITE_OK;
+  }
+
+  /* Search the hash table or tables for an entry matching page number
+  ** pgno. Each iteration of the following for() loop searches one
+  ** hash table (each hash table indexes up to HASHTABLE_NPAGE frames).
+  **
+  ** This code might run concurrently to the code in walIndexAppend()
+  ** that adds entries to the wal-index (and possibly to this hash
+  ** table). This means the value just read from the hash
+  ** slot (aHash[iKey]) may have been added before or after the
+  ** current read transaction was opened. Values added after the
+  ** read transaction was opened may have been written incorrectly -
+  ** i.e. these slots may contain garbage data. However, we assume
+  ** that any slots written before the current read transaction was
+  ** opened remain unmodified.
+  **
+  ** For the reasons above, the if(...) condition featured in the inner
+  ** loop of the following block is more stringent that would be required
+  ** if we had exclusive access to the hash-table:
+  **
+  **   (aPgno[iFrame]==pgno):
+  **     This condition filters out normal hash-table collisions.
+  **
+  **   (iFrame<=iLast):
+  **     This condition filters out entries that were added to the hash
+  **     table after the current read-transaction had started.
+  */
+  iMinHash = walFramePage(pWal->minFrame);
+  for(iHash=walFramePage(iLast); iHash>=iMinHash; iHash--){
+    WalHashLoc sLoc;              /* Hash table location */
+    int iKey;                     /* Hash slot index */
+    int nCollide;                 /* Number of hash collisions remaining */
+    int rc;                       /* Error code */
+    u32 iH;
+
+    rc = walHashGet(pWal, iHash, &sLoc);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    nCollide = HASHTABLE_NSLOT;
+    iKey = walHash(pgno);
+    SEH_INJECT_FAULT;
+    while( (iH = AtomicLoad(&sLoc.aHash[iKey]))!=0 ){
+      u32 iFrame = iH + sLoc.iZero;
+      if( iFrame<=iLast && iFrame>=pWal->minFrame && sLoc.aPgno[iH-1]==pgno ){
+        assert( iFrame>iRead || CORRUPT_DB );
+        iRead = iFrame;
+      }
+      if( (nCollide--)==0 ){
+        *piRead = 0;
+        return SQLITE_CORRUPT_BKPT;
+      }
+      iKey = walNextHash(iKey);
+    }
+    if( iRead ) break;
+  }
+
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+  /* If expensive assert() statements are available, do a linear search
+  ** of the wal-index file content. Make sure the results agree with the
+  ** result obtained using the hash indexes above.  */
+  {
+    u32 iRead2 = 0;
+    u32 iTest;
+    assert( pWal->bShmUnreliable || pWal->minFrame>0 );
+    for(iTest=iLast; iTest>=pWal->minFrame && iTest>0; iTest--){
+      if( walFramePgno(pWal, iTest)==pgno ){
+        iRead2 = iTest;
+        break;
+      }
+    }
+    assert( iRead==iRead2 );
+  }
+#endif
+
+  *piRead = iRead;
+  return SQLITE_OK;
+}
+
+/*
+** Search the wal file for page pgno. If found, set *piRead to the frame that
+** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
+** to zero.
+**
+** Return SQLITE_OK if successful, or an error code if an error occurs. If an
+** error does occur, the final value of *piRead is undefined.
+**
+** The difference between this function and walFindFrame() is that this
+** function wraps walFindFrame() in an SEH_TRY{...} block.
+*/
+SQLITE_PRIVATE int sqlite3WalFindFrame(
+  Wal *pWal,                      /* WAL handle */
+  Pgno pgno,                      /* Database page number to read data for */
+  u32 *piRead                     /* OUT: Frame number (or zero) */
+){
+  int rc;
+  SEH_TRY {
+    rc = walFindFrame(pWal, pgno, piRead);
+  }
+  SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+  return rc;
+}
+
+/*
+** Read the contents of frame iRead from the wal file into buffer pOut
+** (which is nOut bytes in size). Return SQLITE_OK if successful, or an
+** error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3WalReadFrame(
+  Wal *pWal,                      /* WAL handle */
+  u32 iRead,                      /* Frame to read */
+  int nOut,                       /* Size of buffer pOut in bytes */
+  u8 *pOut                        /* Buffer to write page data to */
+){
+  int sz;
+  i64 iOffset;
+  sz = pWal->hdr.szPage;
+  sz = (sz&0xfe00) + ((sz&0x0001)<<16);
+  testcase( sz<=32768 );
+  testcase( sz>=65536 );
+  iOffset = walFrameOffset(iRead, sz) + WAL_FRAME_HDRSIZE;
+  /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
+  return sqlite3OsRead(pWal->pWalFd, pOut, (nOut>sz ? sz : nOut), iOffset);
+}
+
+/*
+** Return the size of the database in pages (or zero, if unknown).
+*/
+SQLITE_PRIVATE Pgno sqlite3WalDbsize(Wal *pWal){
+  if( pWal && ALWAYS(pWal->readLock>=0) ){
+    return pWal->hdr.nPage;
+  }
+  return 0;
+}
+
+
+/*
+** This function starts a write transaction on the WAL.
+**
+** A read transaction must have already been started by a prior call
+** to sqlite3WalBeginReadTransaction().
+**
+** If another thread or process has written into the database since
+** the read transaction was started, then it is not possible for this
+** thread to write as doing so would cause a fork.  So this routine
+** returns SQLITE_BUSY in that case and no write transaction is started.
+**
+** There can only be a single writer active at a time.
+*/
+SQLITE_PRIVATE int sqlite3WalBeginWriteTransaction(Wal *pWal){
+  int rc;
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  /* If the write-lock is already held, then it was obtained before the
+  ** read-transaction was even opened, making this call a no-op.
+  ** Return early. */
+  if( pWal->writeLock ){
+    assert( !memcmp(&pWal->hdr,(void *)walIndexHdr(pWal),sizeof(WalIndexHdr)) );
+    return SQLITE_OK;
+  }
+#endif
+
+  /* Cannot start a write transaction without first holding a read
+  ** transaction. */
+  assert( pWal->readLock>=0 );
+  assert( pWal->writeLock==0 && pWal->iReCksum==0 );
+
+  if( pWal->readOnly ){
+    return SQLITE_READONLY;
+  }
+
+  /* Only one writer allowed at a time.  Get the write lock.  Return
+  ** SQLITE_BUSY if unable.
+  */
+  rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1);
+  if( rc ){
+    return rc;
+  }
+  pWal->writeLock = 1;
+
+  /* If another connection has written to the database file since the
+  ** time the read transaction on this connection was started, then
+  ** the write is disallowed.
+  */
+  SEH_TRY {
+    if( memcmp(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr))!=0 ){
+      rc = SQLITE_BUSY_SNAPSHOT;
+    }
+  }
+  SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+
+  if( rc!=SQLITE_OK ){
+    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+    pWal->writeLock = 0;
+  }
+  return rc;
+}
+
+/*
+** End a write transaction.  The commit has already been done.  This
+** routine merely releases the lock.
+*/
+SQLITE_PRIVATE int sqlite3WalEndWriteTransaction(Wal *pWal){
+  if( pWal->writeLock ){
+    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+    pWal->writeLock = 0;
+    pWal->iReCksum = 0;
+    pWal->truncateOnCommit = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** If any data has been written (but not committed) to the log file, this
+** function moves the write-pointer back to the start of the transaction.
+**
+** Additionally, the callback function is invoked for each frame written
+** to the WAL since the start of the transaction. If the callback returns
+** other than SQLITE_OK, it is not invoked again and the error code is
+** returned to the caller.
+**
+** Otherwise, if the callback function does not return an error, this
+** function returns SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
+  int rc = SQLITE_OK;
+  if( ALWAYS(pWal->writeLock) ){
+    Pgno iMax = pWal->hdr.mxFrame;
+    Pgno iFrame;
+
+    SEH_TRY {
+      /* Restore the clients cache of the wal-index header to the state it
+      ** was in before the client began writing to the database.
+      */
+      memcpy(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr));
+
+      for(iFrame=pWal->hdr.mxFrame+1;
+          ALWAYS(rc==SQLITE_OK) && iFrame<=iMax;
+          iFrame++
+      ){
+        /* This call cannot fail. Unless the page for which the page number
+        ** is passed as the second argument is (a) in the cache and
+        ** (b) has an outstanding reference, then xUndo is either a no-op
+        ** (if (a) is false) or simply expels the page from the cache (if (b)
+        ** is false).
+        **
+        ** If the upper layer is doing a rollback, it is guaranteed that there
+        ** are no outstanding references to any page other than page 1. And
+        ** page 1 is never written to the log until the transaction is
+        ** committed. As a result, the call to xUndo may not fail.
+        */
+        assert( walFramePgno(pWal, iFrame)!=1 );
+        rc = xUndo(pUndoCtx, walFramePgno(pWal, iFrame));
+      }
+      if( iMax!=pWal->hdr.mxFrame ) walCleanupHash(pWal);
+    }
+    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+  }
+  return rc;
+}
+
+/*
+** Argument aWalData must point to an array of WAL_SAVEPOINT_NDATA u32
+** values. This function populates the array with values required to
+** "rollback" the write position of the WAL handle back to the current
+** point in the event of a savepoint rollback (via WalSavepointUndo()).
+*/
+SQLITE_PRIVATE void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData){
+  assert( pWal->writeLock );
+  aWalData[0] = pWal->hdr.mxFrame;
+  aWalData[1] = pWal->hdr.aFrameCksum[0];
+  aWalData[2] = pWal->hdr.aFrameCksum[1];
+  aWalData[3] = pWal->nCkpt;
+}
+
+/*
+** Move the write position of the WAL back to the point identified by
+** the values in the aWalData[] array. aWalData must point to an array
+** of WAL_SAVEPOINT_NDATA u32 values that has been previously populated
+** by a call to WalSavepoint().
+*/
+SQLITE_PRIVATE int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData){
+  int rc = SQLITE_OK;
+
+  assert( pWal->writeLock );
+  assert( aWalData[3]!=pWal->nCkpt || aWalData[0]<=pWal->hdr.mxFrame );
+
+  if( aWalData[3]!=pWal->nCkpt ){
+    /* This savepoint was opened immediately after the write-transaction
+    ** was started. Right after that, the writer decided to wrap around
+    ** to the start of the log. Update the savepoint values to match.
+    */
+    aWalData[0] = 0;
+    aWalData[3] = pWal->nCkpt;
+  }
+
+  if( aWalData[0]<pWal->hdr.mxFrame ){
+    pWal->hdr.mxFrame = aWalData[0];
+    pWal->hdr.aFrameCksum[0] = aWalData[1];
+    pWal->hdr.aFrameCksum[1] = aWalData[2];
+    SEH_TRY {
+      walCleanupHash(pWal);
+    }
+    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+  }
+
+  return rc;
+}
+
+/*
+** This function is called just before writing a set of frames to the log
+** file (see sqlite3WalFrames()). It checks to see if, instead of appending
+** to the current log file, it is possible to overwrite the start of the
+** existing log file with the new frames (i.e. "reset" the log). If so,
+** it sets pWal->hdr.mxFrame to 0. Otherwise, pWal->hdr.mxFrame is left
+** unchanged.
+**
+** SQLITE_OK is returned if no error is encountered (regardless of whether
+** or not pWal->hdr.mxFrame is modified). An SQLite error code is returned
+** if an error occurs.
+*/
+static int walRestartLog(Wal *pWal){
+  int rc = SQLITE_OK;
+  int cnt;
+
+  if( pWal->readLock==0 ){
+    volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
+    assert( pInfo->nBackfill==pWal->hdr.mxFrame );
+    if( pInfo->nBackfill>0 ){
+      u32 salt1;
+      sqlite3_randomness(4, &salt1);
+      rc = walLockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
+      if( rc==SQLITE_OK ){
+        /* If all readers are using WAL_READ_LOCK(0) (in other words if no
+        ** readers are currently using the WAL), then the transactions
+        ** frames will overwrite the start of the existing log. Update the
+        ** wal-index header to reflect this.
+        **
+        ** In theory it would be Ok to update the cache of the header only
+        ** at this point. But updating the actual wal-index header is also
+        ** safe and means there is no special case for sqlite3WalUndo()
+        ** to handle if this transaction is rolled back.  */
+        walRestartHdr(pWal, salt1);
+        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
+      }else if( rc!=SQLITE_BUSY ){
+        return rc;
+      }
+    }
+    walUnlockShared(pWal, WAL_READ_LOCK(0));
+    pWal->readLock = -1;
+    cnt = 0;
+    do{
+      int notUsed;
+      rc = walTryBeginRead(pWal, ¬Used, 1, &cnt);
+    }while( rc==WAL_RETRY );
+    assert( (rc&0xff)!=SQLITE_BUSY ); /* BUSY not possible when useWal==1 */
+    testcase( (rc&0xff)==SQLITE_IOERR );
+    testcase( rc==SQLITE_PROTOCOL );
+    testcase( rc==SQLITE_OK );
+  }
+  return rc;
+}
+
+/*
+** Information about the current state of the WAL file and where
+** the next fsync should occur - passed from sqlite3WalFrames() into
+** walWriteToLog().
+*/
+typedef struct WalWriter {
+  Wal *pWal;                   /* The complete WAL information */
+  sqlite3_file *pFd;           /* The WAL file to which we write */
+  sqlite3_int64 iSyncPoint;    /* Fsync at this offset */
+  int syncFlags;               /* Flags for the fsync */
+  int szPage;                  /* Size of one page */
+} WalWriter;
+
+/*
+** Write iAmt bytes of content into the WAL file beginning at iOffset.
+** Do a sync when crossing the p->iSyncPoint boundary.
+**
+** In other words, if iSyncPoint is in between iOffset and iOffset+iAmt,
+** first write the part before iSyncPoint, then sync, then write the
+** rest.
+*/
+static int walWriteToLog(
+  WalWriter *p,              /* WAL to write to */
+  void *pContent,            /* Content to be written */
+  int iAmt,                  /* Number of bytes to write */
+  sqlite3_int64 iOffset      /* Start writing at this offset */
+){
+  int rc;
+  if( iOffset<p->iSyncPoint && iOffset+iAmt>=p->iSyncPoint ){
+    int iFirstAmt = (int)(p->iSyncPoint - iOffset);
+    rc = sqlite3OsWrite(p->pFd, pContent, iFirstAmt, iOffset);
+    if( rc ) return rc;
+    iOffset += iFirstAmt;
+    iAmt -= iFirstAmt;
+    pContent = (void*)(iFirstAmt + (char*)pContent);
+    assert( WAL_SYNC_FLAGS(p->syncFlags)!=0 );
+    rc = sqlite3OsSync(p->pFd, WAL_SYNC_FLAGS(p->syncFlags));
+    if( iAmt==0 || rc ) return rc;
+  }
+  rc = sqlite3OsWrite(p->pFd, pContent, iAmt, iOffset);
+  return rc;
+}
+
+/*
+** Write out a single frame of the WAL
+*/
+static int walWriteOneFrame(
+  WalWriter *p,               /* Where to write the frame */
+  PgHdr *pPage,               /* The page of the frame to be written */
+  int nTruncate,              /* The commit flag.  Usually 0.  >0 for commit */
+  sqlite3_int64 iOffset       /* Byte offset at which to write */
+){
+  int rc;                         /* Result code from subfunctions */
+  void *pData;                    /* Data actually written */
+  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-header in */
+  pData = pPage->pData;
+  walEncodeFrame(p->pWal, pPage->pgno, nTruncate, pData, aFrame);
+  rc = walWriteToLog(p, aFrame, sizeof(aFrame), iOffset);
+  if( rc ) return rc;
+  /* Write the page data */
+  rc = walWriteToLog(p, pData, p->szPage, iOffset+sizeof(aFrame));
+  return rc;
+}
+
+/*
+** This function is called as part of committing a transaction within which
+** one or more frames have been overwritten. It updates the checksums for
+** all frames written to the wal file by the current transaction starting
+** with the earliest to have been overwritten.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+static int walRewriteChecksums(Wal *pWal, u32 iLast){
+  const int szPage = pWal->szPage;/* Database page size */
+  int rc = SQLITE_OK;             /* Return code */
+  u8 *aBuf;                       /* Buffer to load data from wal file into */
+  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-headers in */
+  u32 iRead;                      /* Next frame to read from wal file */
+  i64 iCksumOff;
+
+  aBuf = sqlite3_malloc(szPage + WAL_FRAME_HDRSIZE);
+  if( aBuf==0 ) return SQLITE_NOMEM_BKPT;
+
+  /* Find the checksum values to use as input for the recalculating the
+  ** first checksum. If the first frame is frame 1 (implying that the current
+  ** transaction restarted the wal file), these values must be read from the
+  ** wal-file header. Otherwise, read them from the frame header of the
+  ** previous frame.  */
+  assert( pWal->iReCksum>0 );
+  if( pWal->iReCksum==1 ){
+    iCksumOff = 24;
+  }else{
+    iCksumOff = walFrameOffset(pWal->iReCksum-1, szPage) + 16;
+  }
+  rc = sqlite3OsRead(pWal->pWalFd, aBuf, sizeof(u32)*2, iCksumOff);
+  pWal->hdr.aFrameCksum[0] = sqlite3Get4byte(aBuf);
+  pWal->hdr.aFrameCksum[1] = sqlite3Get4byte(&aBuf[sizeof(u32)]);
+
+  iRead = pWal->iReCksum;
+  pWal->iReCksum = 0;
+  for(; rc==SQLITE_OK && iRead<=iLast; iRead++){
+    i64 iOff = walFrameOffset(iRead, szPage);
+    rc = sqlite3OsRead(pWal->pWalFd, aBuf, szPage+WAL_FRAME_HDRSIZE, iOff);
+    if( rc==SQLITE_OK ){
+      u32 iPgno, nDbSize;
+      iPgno = sqlite3Get4byte(aBuf);
+      nDbSize = sqlite3Get4byte(&aBuf[4]);
+
+      walEncodeFrame(pWal, iPgno, nDbSize, &aBuf[WAL_FRAME_HDRSIZE], aFrame);
+      rc = sqlite3OsWrite(pWal->pWalFd, aFrame, sizeof(aFrame), iOff);
+    }
+  }
+
+  sqlite3_free(aBuf);
+  return rc;
+}
+
+/*
+** Write a set of frames to the log. The caller must hold the write-lock
+** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
+*/
+static int walFrames(
+  Wal *pWal,                      /* Wal handle to write to */
+  int szPage,                     /* Database page-size in bytes */
+  PgHdr *pList,                   /* List of dirty pages to write */
+  Pgno nTruncate,                 /* Database size after this commit */
+  int isCommit,                   /* True if this is a commit */
+  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
+){
+  int rc;                         /* Used to catch return codes */
+  u32 iFrame;                     /* Next frame address */
+  PgHdr *p;                       /* Iterator to run through pList with. */
+  PgHdr *pLast = 0;               /* Last frame in list */
+  int nExtra = 0;                 /* Number of extra copies of last page */
+  int szFrame;                    /* The size of a single frame */
+  i64 iOffset;                    /* Next byte to write in WAL file */
+  WalWriter w;                    /* The writer */
+  u32 iFirst = 0;                 /* First frame that may be overwritten */
+  WalIndexHdr *pLive;             /* Pointer to shared header */
+
+  assert( pList );
+  assert( pWal->writeLock );
+
+  /* If this frame set completes a transaction, then nTruncate>0.  If
+  ** nTruncate==0 then this frame set does not complete the transaction. */
+  assert( (isCommit!=0)==(nTruncate!=0) );
+
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+  { int cnt; for(cnt=0, p=pList; p; p=p->pDirty, cnt++){}
+    WALTRACE(("WAL%p: frame write begin. %d frames. mxFrame=%d. %s\n",
+              pWal, cnt, pWal->hdr.mxFrame, isCommit ? "Commit" : "Spill"));
+  }
+#endif
+
+  pLive = (WalIndexHdr*)walIndexHdr(pWal);
+  if( memcmp(&pWal->hdr, (void *)pLive, sizeof(WalIndexHdr))!=0 ){
+    iFirst = pLive->mxFrame+1;
+  }
+
+  /* See if it is possible to write these frames into the start of the
+  ** log file, instead of appending to it at pWal->hdr.mxFrame.
+  */
+  if( SQLITE_OK!=(rc = walRestartLog(pWal)) ){
+    return rc;
+  }
+
+  /* If this is the first frame written into the log, write the WAL
+  ** header to the start of the WAL file. See comments at the top of
+  ** this source file for a description of the WAL header format.
+  */
+  iFrame = pWal->hdr.mxFrame;
+  if( iFrame==0 ){
+    u8 aWalHdr[WAL_HDRSIZE];      /* Buffer to assemble wal-header in */
+    u32 aCksum[2];                /* Checksum for wal-header */
+
+    sqlite3Put4byte(&aWalHdr[0], (WAL_MAGIC | SQLITE_BIGENDIAN));
+    sqlite3Put4byte(&aWalHdr[4], WAL_MAX_VERSION);
+    sqlite3Put4byte(&aWalHdr[8], szPage);
+    sqlite3Put4byte(&aWalHdr[12], pWal->nCkpt);
+    if( pWal->nCkpt==0 ) sqlite3_randomness(8, pWal->hdr.aSalt);
+    memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8);
+    walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum);
+    sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
+    sqlite3Put4byte(&aWalHdr[28], aCksum[1]);
+
+    pWal->szPage = szPage;
+    pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
+    pWal->hdr.aFrameCksum[0] = aCksum[0];
+    pWal->hdr.aFrameCksum[1] = aCksum[1];
+    pWal->truncateOnCommit = 1;
+
+    rc = sqlite3OsWrite(pWal->pWalFd, aWalHdr, sizeof(aWalHdr), 0);
+    WALTRACE(("WAL%p: wal-header write %s\n", pWal, rc ? "failed" : "ok"));
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    /* Sync the header (unless SQLITE_IOCAP_SEQUENTIAL is true or unless
+    ** all syncing is turned off by PRAGMA synchronous=OFF).  Otherwise
+    ** an out-of-order write following a WAL restart could result in
+    ** database corruption.  See the ticket:
+    **
+    **     https://sqlite.org/src/info/ff5be73dee
+    */
+    if( pWal->syncHeader ){
+      rc = sqlite3OsSync(pWal->pWalFd, CKPT_SYNC_FLAGS(sync_flags));
+      if( rc ) return rc;
+    }
+  }
+  if( (int)pWal->szPage!=szPage ){
+    return SQLITE_CORRUPT_BKPT;  /* TH3 test case: cov1/corrupt155.test */
+  }
+
+  /* Setup information needed to write frames into the WAL */
+  w.pWal = pWal;
+  w.pFd = pWal->pWalFd;
+  w.iSyncPoint = 0;
+  w.syncFlags = sync_flags;
+  w.szPage = szPage;
+  iOffset = walFrameOffset(iFrame+1, szPage);
+  szFrame = szPage + WAL_FRAME_HDRSIZE;
+
+  /* Write all frames into the log file exactly once */
+  for(p=pList; p; p=p->pDirty){
+    int nDbSize;   /* 0 normally.  Positive == commit flag */
+
+    /* Check if this page has already been written into the wal file by
+    ** the current transaction. If so, overwrite the existing frame and
+    ** set Wal.writeLock to WAL_WRITELOCK_RECKSUM - indicating that
+    ** checksums must be recomputed when the transaction is committed.  */
+    if( iFirst && (p->pDirty || isCommit==0) ){
+      u32 iWrite = 0;
+      VVA_ONLY(rc =) walFindFrame(pWal, p->pgno, &iWrite);
+      assert( rc==SQLITE_OK || iWrite==0 );
+      if( iWrite>=iFirst ){
+        i64 iOff = walFrameOffset(iWrite, szPage) + WAL_FRAME_HDRSIZE;
+        void *pData;
+        if( pWal->iReCksum==0 || iWrite<pWal->iReCksum ){
+          pWal->iReCksum = iWrite;
+        }
+        pData = p->pData;
+        rc = sqlite3OsWrite(pWal->pWalFd, pData, szPage, iOff);
+        if( rc ) return rc;
+        p->flags &= ~PGHDR_WAL_APPEND;
+        continue;
+      }
+    }
+
+    iFrame++;
+    assert( iOffset==walFrameOffset(iFrame, szPage) );
+    nDbSize = (isCommit && p->pDirty==0) ? nTruncate : 0;
+    rc = walWriteOneFrame(&w, p, nDbSize, iOffset);
+    if( rc ) return rc;
+    pLast = p;
+    iOffset += szFrame;
+    p->flags |= PGHDR_WAL_APPEND;
+  }
+
+  /* Recalculate checksums within the wal file if required. */
+  if( isCommit && pWal->iReCksum ){
+    rc = walRewriteChecksums(pWal, iFrame);
+    if( rc ) return rc;
+  }
+
+  /* If this is the end of a transaction, then we might need to pad
+  ** the transaction and/or sync the WAL file.
+  **
+  ** Padding and syncing only occur if this set of frames complete a
+  ** transaction and if PRAGMA synchronous=FULL.  If synchronous==NORMAL
+  ** or synchronous==OFF, then no padding or syncing are needed.
+  **
+  ** If SQLITE_IOCAP_POWERSAFE_OVERWRITE is defined, then padding is not
+  ** needed and only the sync is done.  If padding is needed, then the
+  ** final frame is repeated (with its commit mark) until the next sector
+  ** boundary is crossed.  Only the part of the WAL prior to the last
+  ** sector boundary is synced; the part of the last frame that extends
+  ** past the sector boundary is written after the sync.
+  */
+  if( isCommit && WAL_SYNC_FLAGS(sync_flags)!=0 ){
+    int bSync = 1;
+    if( pWal->padToSectorBoundary ){
+      int sectorSize = sqlite3SectorSize(pWal->pWalFd);
+      w.iSyncPoint = ((iOffset+sectorSize-1)/sectorSize)*sectorSize;
+      bSync = (w.iSyncPoint==iOffset);
+      testcase( bSync );
+      while( iOffset<w.iSyncPoint ){
+        rc = walWriteOneFrame(&w, pLast, nTruncate, iOffset);
+        if( rc ) return rc;
+        iOffset += szFrame;
+        nExtra++;
+        assert( pLast!=0 );
+      }
+    }
+    if( bSync ){
+      assert( rc==SQLITE_OK );
+      rc = sqlite3OsSync(w.pFd, WAL_SYNC_FLAGS(sync_flags));
+    }
+  }
+
+  /* If this frame set completes the first transaction in the WAL and
+  ** if PRAGMA journal_size_limit is set, then truncate the WAL to the
+  ** journal size limit, if possible.
+  */
+  if( isCommit && pWal->truncateOnCommit && pWal->mxWalSize>=0 ){
+    i64 sz = pWal->mxWalSize;
+    if( walFrameOffset(iFrame+nExtra+1, szPage)>pWal->mxWalSize ){
+      sz = walFrameOffset(iFrame+nExtra+1, szPage);
+    }
+    walLimitSize(pWal, sz);
+    pWal->truncateOnCommit = 0;
+  }
+
+  /* Append data to the wal-index. It is not necessary to lock the
+  ** wal-index to do this as the SQLITE_SHM_WRITE lock held on the wal-index
+  ** guarantees that there are no other writers, and no data that may
+  ** be in use by existing readers is being overwritten.
+  */
+  iFrame = pWal->hdr.mxFrame;
+  for(p=pList; p && rc==SQLITE_OK; p=p->pDirty){
+    if( (p->flags & PGHDR_WAL_APPEND)==0 ) continue;
+    iFrame++;
+    rc = walIndexAppend(pWal, iFrame, p->pgno);
+  }
+  assert( pLast!=0 || nExtra==0 );
+  while( rc==SQLITE_OK && nExtra>0 ){
+    iFrame++;
+    nExtra--;
+    rc = walIndexAppend(pWal, iFrame, pLast->pgno);
+  }
+
+  if( rc==SQLITE_OK ){
+    /* Update the private copy of the header. */
+    pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
+    testcase( szPage<=32768 );
+    testcase( szPage>=65536 );
+    pWal->hdr.mxFrame = iFrame;
+    if( isCommit ){
+      pWal->hdr.iChange++;
+      pWal->hdr.nPage = nTruncate;
+    }
+    /* If this is a commit, update the wal-index header too. */
+    if( isCommit ){
+      walIndexWriteHdr(pWal);
+      pWal->iCallback = iFrame;
+    }
+  }
+
+  WALTRACE(("WAL%p: frame write %s\n", pWal, rc ? "failed" : "ok"));
+  return rc;
+}
+
+/*
+** Write a set of frames to the log. The caller must hold the write-lock
+** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
+**
+** The difference between this function and walFrames() is that this
+** function wraps walFrames() in an SEH_TRY{...} block.
+*/
+SQLITE_PRIVATE int sqlite3WalFrames(
+  Wal *pWal,                      /* Wal handle to write to */
+  int szPage,                     /* Database page-size in bytes */
+  PgHdr *pList,                   /* List of dirty pages to write */
+  Pgno nTruncate,                 /* Database size after this commit */
+  int isCommit,                   /* True if this is a commit */
+  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
+){
+  int rc;
+  SEH_TRY {
+    rc = walFrames(pWal, szPage, pList, nTruncate, isCommit, sync_flags);
+  }
+  SEH_EXCEPT( rc = walHandleException(pWal); )
+  return rc;
+}
+
+/*
+** This routine is called to implement sqlite3_wal_checkpoint() and
+** related interfaces.
+**
+** Obtain a CHECKPOINT lock and then backfill as much information as
+** we can from WAL into the database.
+**
+** If parameter xBusy is not NULL, it is a pointer to a busy-handler
+** callback. In this case this function runs a blocking checkpoint.
+*/
+SQLITE_PRIVATE int sqlite3WalCheckpoint(
+  Wal *pWal,                      /* Wal connection */
+  sqlite3 *db,                    /* Check this handle's interrupt flag */
+  int eMode,                      /* PASSIVE, FULL, RESTART, or TRUNCATE */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags to sync db file with (or 0) */
+  int nBuf,                       /* Size of temporary buffer */
+  u8 *zBuf,                       /* Temporary buffer to use */
+  int *pnLog,                     /* OUT: Number of frames in WAL */
+  int *pnCkpt                     /* OUT: Number of backfilled frames in WAL */
+){
+  int rc;                         /* Return code */
+  int isChanged = 0;              /* True if a new wal-index header is loaded */
+  int eMode2 = eMode;             /* Mode to pass to walCheckpoint() */
+  int (*xBusy2)(void*) = xBusy;   /* Busy handler for eMode2 */
+
+  assert( pWal->ckptLock==0 );
+  assert( pWal->writeLock==0 );
+
+  /* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
+  ** in the SQLITE_CHECKPOINT_PASSIVE mode. */
+  assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );
+
+  if( pWal->readOnly ) return SQLITE_READONLY;
+  WALTRACE(("WAL%p: checkpoint begins\n", pWal));
+
+  /* Enable blocking locks, if possible. */
+  sqlite3WalDb(pWal, db);
+  if( xBusy2 ) (void)walEnableBlocking(pWal);
+
+  /* IMPLEMENTATION-OF: R-62028-47212 All calls obtain an exclusive
+  ** "checkpoint" lock on the database file.
+  ** EVIDENCE-OF: R-10421-19736 If any other process is running a
+  ** checkpoint operation at the same time, the lock cannot be obtained and
+  ** SQLITE_BUSY is returned.
+  ** EVIDENCE-OF: R-53820-33897 Even if there is a busy-handler configured,
+  ** it will not be invoked in this case.
+  */
+  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
+  testcase( rc==SQLITE_BUSY );
+  testcase( rc!=SQLITE_OK && xBusy2!=0 );
+  if( rc==SQLITE_OK ){
+    pWal->ckptLock = 1;
+
+    /* IMPLEMENTATION-OF: R-59782-36818 The SQLITE_CHECKPOINT_FULL, RESTART and
+    ** TRUNCATE modes also obtain the exclusive "writer" lock on the database
+    ** file.
+    **
+    ** EVIDENCE-OF: R-60642-04082 If the writer lock cannot be obtained
+    ** immediately, and a busy-handler is configured, it is invoked and the
+    ** writer lock retried until either the busy-handler returns 0 or the
+    ** lock is successfully obtained.
+    */
+    if( eMode!=SQLITE_CHECKPOINT_PASSIVE ){
+      rc = walBusyLock(pWal, xBusy2, pBusyArg, WAL_WRITE_LOCK, 1);
+      if( rc==SQLITE_OK ){
+        pWal->writeLock = 1;
+      }else if( rc==SQLITE_BUSY ){
+        eMode2 = SQLITE_CHECKPOINT_PASSIVE;
+        xBusy2 = 0;
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+
+  /* Read the wal-index header. */
+  SEH_TRY {
+    if( rc==SQLITE_OK ){
+      /* For a passive checkpoint, do not re-enable blocking locks after
+      ** reading the wal-index header. A passive checkpoint should not block
+      ** or invoke the busy handler. The only lock such a checkpoint may
+      ** attempt to obtain is a lock on a read-slot, and it should give up
+      ** immediately and do a partial checkpoint if it cannot obtain it. */
+      walDisableBlocking(pWal);
+      rc = walIndexReadHdr(pWal, &isChanged);
+      if( eMode2!=SQLITE_CHECKPOINT_PASSIVE ) (void)walEnableBlocking(pWal);
+      if( isChanged && pWal->pDbFd->pMethods->iVersion>=3 ){
+        sqlite3OsUnfetch(pWal->pDbFd, 0, 0);
+      }
+    }
+
+    /* Copy data from the log to the database file. */
+    if( rc==SQLITE_OK ){
+      if( pWal->hdr.mxFrame && walPagesize(pWal)!=nBuf ){
+        rc = SQLITE_CORRUPT_BKPT;
+      }else{
+        rc = walCheckpoint(pWal, db, eMode2, xBusy2, pBusyArg, sync_flags,zBuf);
+      }
+
+      /* If no error occurred, set the output variables. */
+      if( rc==SQLITE_OK || rc==SQLITE_BUSY ){
+        if( pnLog ) *pnLog = (int)pWal->hdr.mxFrame;
+        SEH_INJECT_FAULT;
+        if( pnCkpt ) *pnCkpt = (int)(walCkptInfo(pWal)->nBackfill);
+      }
+    }
+  }
+  SEH_EXCEPT( rc = walHandleException(pWal); )
+
+  if( isChanged ){
+    /* If a new wal-index header was loaded before the checkpoint was
+    ** performed, then the pager-cache associated with pWal is now
+    ** out of date. So zero the cached wal-index header to ensure that
+    ** next time the pager opens a snapshot on this database it knows that
+    ** the cache needs to be reset.
+    */
+    memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
+  }
+
+  walDisableBlocking(pWal);
+  sqlite3WalDb(pWal, 0);
+
+  /* Release the locks. */
+  sqlite3WalEndWriteTransaction(pWal);
+  if( pWal->ckptLock ){
+    walUnlockExclusive(pWal, WAL_CKPT_LOCK, 1);
+    pWal->ckptLock = 0;
+  }
+  WALTRACE(("WAL%p: checkpoint %s\n", pWal, rc ? "failed" : "ok"));
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  if( rc==SQLITE_BUSY_TIMEOUT ) rc = SQLITE_BUSY;
+#endif
+  return (rc==SQLITE_OK && eMode!=eMode2 ? SQLITE_BUSY : rc);
+}
+
+/* Return the value to pass to a sqlite3_wal_hook callback, the
+** number of frames in the WAL at the point of the last commit since
+** sqlite3WalCallback() was called.  If no commits have occurred since
+** the last call, then return 0.
+*/
+SQLITE_PRIVATE int sqlite3WalCallback(Wal *pWal){
+  u32 ret = 0;
+  if( pWal ){
+    ret = pWal->iCallback;
+    pWal->iCallback = 0;
+  }
+  return (int)ret;
+}
+
+/*
+** This function is called to change the WAL subsystem into or out
+** of locking_mode=EXCLUSIVE.
+**
+** If op is zero, then attempt to change from locking_mode=EXCLUSIVE
+** into locking_mode=NORMAL.  This means that we must acquire a lock
+** on the pWal->readLock byte.  If the WAL is already in locking_mode=NORMAL
+** or if the acquisition of the lock fails, then return 0.  If the
+** transition out of exclusive-mode is successful, return 1.  This
+** operation must occur while the pager is still holding the exclusive
+** lock on the main database file.
+**
+** If op is one, then change from locking_mode=NORMAL into
+** locking_mode=EXCLUSIVE.  This means that the pWal->readLock must
+** be released.  Return 1 if the transition is made and 0 if the
+** WAL is already in exclusive-locking mode - meaning that this
+** routine is a no-op.  The pager must already hold the exclusive lock
+** on the main database file before invoking this operation.
+**
+** If op is negative, then do a dry-run of the op==1 case but do
+** not actually change anything. The pager uses this to see if it
+** should acquire the database exclusive lock prior to invoking
+** the op==1 case.
+*/
+SQLITE_PRIVATE int sqlite3WalExclusiveMode(Wal *pWal, int op){
+  int rc;
+  assert( pWal->writeLock==0 );
+  assert( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE || op==-1 );
+
+  /* pWal->readLock is usually set, but might be -1 if there was a
+  ** prior error while attempting to acquire are read-lock. This cannot
+  ** happen if the connection is actually in exclusive mode (as no xShmLock
+  ** locks are taken in this case). Nor should the pager attempt to
+  ** upgrade to exclusive-mode following such an error.
+  */
+#ifndef SQLITE_USE_SEH
+  assert( pWal->readLock>=0 || pWal->lockError );
+#endif
+  assert( pWal->readLock>=0 || (op<=0 && pWal->exclusiveMode==0) );
+
+  if( op==0 ){
+    if( pWal->exclusiveMode!=WAL_NORMAL_MODE ){
+      pWal->exclusiveMode = WAL_NORMAL_MODE;
+      if( walLockShared(pWal, WAL_READ_LOCK(pWal->readLock))!=SQLITE_OK ){
+        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
+      }
+      rc = pWal->exclusiveMode==WAL_NORMAL_MODE;
+    }else{
+      /* Already in locking_mode=NORMAL */
+      rc = 0;
+    }
+  }else if( op>0 ){
+    assert( pWal->exclusiveMode==WAL_NORMAL_MODE );
+    assert( pWal->readLock>=0 );
+    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
+    pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
+    rc = 1;
+  }else{
+    rc = pWal->exclusiveMode==WAL_NORMAL_MODE;
+  }
+  return rc;
+}
+
+/*
+** Return true if the argument is non-NULL and the WAL module is using
+** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
+** WAL module is using shared-memory, return false.
+*/
+SQLITE_PRIVATE int sqlite3WalHeapMemory(Wal *pWal){
+  return (pWal && pWal->exclusiveMode==WAL_HEAPMEMORY_MODE );
+}
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+/* Create a snapshot object.  The content of a snapshot is opaque to
+** every other subsystem, so the WAL module can put whatever it needs
+** in the object.
+*/
+SQLITE_PRIVATE int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot){
+  int rc = SQLITE_OK;
+  WalIndexHdr *pRet;
+  static const u32 aZero[4] = { 0, 0, 0, 0 };
+
+  assert( pWal->readLock>=0 && pWal->writeLock==0 );
+
+  if( memcmp(&pWal->hdr.aFrameCksum[0],aZero,16)==0 ){
+    *ppSnapshot = 0;
+    return SQLITE_ERROR;
+  }
+  pRet = (WalIndexHdr*)sqlite3_malloc(sizeof(WalIndexHdr));
+  if( pRet==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+  }else{
+    memcpy(pRet, &pWal->hdr, sizeof(WalIndexHdr));
+    *ppSnapshot = (sqlite3_snapshot*)pRet;
+  }
+
+  return rc;
+}
+
+/* Try to open on pSnapshot when the next read-transaction starts
+*/
+SQLITE_PRIVATE void sqlite3WalSnapshotOpen(
+  Wal *pWal,
+  sqlite3_snapshot *pSnapshot
+){
+  if( pSnapshot && ((WalIndexHdr*)pSnapshot)->iVersion==0 ){
+    /* iVersion==0 means that this is a call to sqlite3_snapshot_get().  In
+    ** this case set the bGetSnapshot flag so that if the call to
+    ** sqlite3_snapshot_get() is about to read transaction on this wal
+    ** file, it does not take read-lock 0 if the wal file has been completely
+    ** checkpointed. Taking read-lock 0 would work, but then it would be
+    ** possible for a subsequent writer to destroy the snapshot even while
+    ** this connection is holding its read-transaction open. This is contrary
+    ** to user expectations, so we avoid it by not taking read-lock 0. */
+    pWal->bGetSnapshot = 1;
+  }else{
+    pWal->pSnapshot = (WalIndexHdr*)pSnapshot;
+    pWal->bGetSnapshot = 0;
+  }
+}
+
+/*
+** Return a +ve value if snapshot p1 is newer than p2. A -ve value if
+** p1 is older than p2 and zero if p1 and p2 are the same snapshot.
+*/
+SQLITE_API int sqlite3_snapshot_cmp(sqlite3_snapshot *p1, sqlite3_snapshot *p2){
+  WalIndexHdr *pHdr1 = (WalIndexHdr*)p1;
+  WalIndexHdr *pHdr2 = (WalIndexHdr*)p2;
+
+  /* aSalt[0] is a copy of the value stored in the wal file header. It
+  ** is incremented each time the wal file is restarted.  */
+  if( pHdr1->aSalt[0]<pHdr2->aSalt[0] ) return -1;
+  if( pHdr1->aSalt[0]>pHdr2->aSalt[0] ) return +1;
+  if( pHdr1->mxFrame<pHdr2->mxFrame ) return -1;
+  if( pHdr1->mxFrame>pHdr2->mxFrame ) return +1;
+  return 0;
+}
+
+/*
+** The caller currently has a read transaction open on the database.
+** This function takes a SHARED lock on the CHECKPOINTER slot and then
+** checks if the snapshot passed as the second argument is still
+** available. If so, SQLITE_OK is returned.
+**
+** If the snapshot is not available, SQLITE_ERROR is returned. Or, if
+** the CHECKPOINTER lock cannot be obtained, SQLITE_BUSY. If any error
+** occurs (any value other than SQLITE_OK is returned), the CHECKPOINTER
+** lock is released before returning.
+*/
+SQLITE_PRIVATE int sqlite3WalSnapshotCheck(Wal *pWal, sqlite3_snapshot *pSnapshot){
+  int rc;
+  SEH_TRY {
+    rc = walLockShared(pWal, WAL_CKPT_LOCK);
+    if( rc==SQLITE_OK ){
+      WalIndexHdr *pNew = (WalIndexHdr*)pSnapshot;
+      if( memcmp(pNew->aSalt, pWal->hdr.aSalt, sizeof(pWal->hdr.aSalt))
+       || pNew->mxFrame<walCkptInfo(pWal)->nBackfillAttempted
+      ){
+        rc = SQLITE_ERROR_SNAPSHOT;
+        walUnlockShared(pWal, WAL_CKPT_LOCK);
+      }
+    }
+  }
+  SEH_EXCEPT( rc = walHandleException(pWal); )
+  return rc;
+}
+
+/*
+** Release a lock obtained by an earlier successful call to
+** sqlite3WalSnapshotCheck().
+*/
+SQLITE_PRIVATE void sqlite3WalSnapshotUnlock(Wal *pWal){
+  assert( pWal );
+  walUnlockShared(pWal, WAL_CKPT_LOCK);
+}
+
+
+#endif /* SQLITE_ENABLE_SNAPSHOT */
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/*
+** If the argument is not NULL, it points to a Wal object that holds a
+** read-lock. This function returns the database page-size if it is known,
+** or zero if it is not (or if pWal is NULL).
+*/
+SQLITE_PRIVATE int sqlite3WalFramesize(Wal *pWal){
+  assert( pWal==0 || pWal->readLock>=0 );
+  return (pWal ? pWal->szPage : 0);
+}
+#endif
+
+/* Return the sqlite3_file object for the WAL file
+*/
+SQLITE_PRIVATE sqlite3_file *sqlite3WalFile(Wal *pWal){
+  return pWal->pWalFd;
+}
+
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
+/************** End of wal.c *************************************************/
+/************** Begin file btmutex.c *****************************************/
+/*
+** 2007 August 27
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code used to implement mutexes on Btree objects.
+** This code really belongs in btree.c.  But btree.c is getting too
+** big and we want to break it down some.  This packaged seemed like
+** a good breakout.
+*/
+/************** Include btreeInt.h in the middle of btmutex.c ****************/
+/************** Begin file btreeInt.h ****************************************/
+/*
+** 2004 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements an external (disk-based) database using BTrees.
+** For a detailed discussion of BTrees, refer to
+**
+**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
+**     "Sorting And Searching", pages 473-480. Addison-Wesley
+**     Publishing Company, Reading, Massachusetts.
+**
+** The basic idea is that each page of the file contains N database
+** entries and N+1 pointers to subpages.
+**
+**   ----------------------------------------------------------------
+**   |  Ptr(0) | Key(0) | Ptr(1) | Key(1) | ... | Key(N-1) | Ptr(N) |
+**   ----------------------------------------------------------------
+**
+** All of the keys on the page that Ptr(0) points to have values less
+** than Key(0).  All of the keys on page Ptr(1) and its subpages have
+** values greater than Key(0) and less than Key(1).  All of the keys
+** on Ptr(N) and its subpages have values greater than Key(N-1).  And
+** so forth.
+**
+** Finding a particular key requires reading O(log(M)) pages from the
+** disk where M is the number of entries in the tree.
+**
+** In this implementation, a single file can hold one or more separate
+** BTrees.  Each BTree is identified by the index of its root page.  The
+** key and data for any entry are combined to form the "payload".  A
+** fixed amount of payload can be carried directly on the database
+** page.  If the payload is larger than the preset amount then surplus
+** bytes are stored on overflow pages.  The payload for an entry
+** and the preceding pointer are combined to form a "Cell".  Each
+** page has a small header which contains the Ptr(N) pointer and other
+** information such as the size of key and data.
+**
+** FORMAT DETAILS
+**
+** The file is divided into pages.  The first page is called page 1,
+** the second is page 2, and so forth.  A page number of zero indicates
+** "no such page".  The page size can be any power of 2 between 512 and 65536.
+** Each page can be either a btree page, a freelist page, an overflow
+** page, or a pointer-map page.
+**
+** The first page is always a btree page.  The first 100 bytes of the first
+** page contain a special header (the "file header") that describes the file.
+** The format of the file header is as follows:
+**
+**   OFFSET   SIZE    DESCRIPTION
+**      0      16     Header string: "SQLite format 3\000"
+**     16       2     Page size in bytes.  (1 means 65536)
+**     18       1     File format write version
+**     19       1     File format read version
+**     20       1     Bytes of unused space at the end of each page
+**     21       1     Max embedded payload fraction (must be 64)
+**     22       1     Min embedded payload fraction (must be 32)
+**     23       1     Min leaf payload fraction (must be 32)
+**     24       4     File change counter
+**     28       4     The size of the database in pages
+**     32       4     First freelist page
+**     36       4     Number of freelist pages in the file
+**     40      60     15 4-byte meta values passed to higher layers
+**
+**     40       4     Schema cookie
+**     44       4     File format of schema layer
+**     48       4     Size of page cache
+**     52       4     Largest root-page (auto/incr_vacuum)
+**     56       4     1=UTF-8 2=UTF16le 3=UTF16be
+**     60       4     User version
+**     64       4     Incremental vacuum mode
+**     68       4     Application-ID
+**     72      20     unused
+**     92       4     The version-valid-for number
+**     96       4     SQLITE_VERSION_NUMBER
+**
+** All of the integer values are big-endian (most significant byte first).
+**
+** The file change counter is incremented when the database is changed
+** This counter allows other processes to know when the file has changed
+** and thus when they need to flush their cache.
+**
+** The max embedded payload fraction is the amount of the total usable
+** space in a page that can be consumed by a single cell for standard
+** B-tree (non-LEAFDATA) tables.  A value of 255 means 100%.  The default
+** is to limit the maximum cell size so that at least 4 cells will fit
+** on one page.  Thus the default max embedded payload fraction is 64.
+**
+** If the payload for a cell is larger than the max payload, then extra
+** payload is spilled to overflow pages.  Once an overflow page is allocated,
+** as many bytes as possible are moved into the overflow pages without letting
+** the cell size drop below the min embedded payload fraction.
+**
+** The min leaf payload fraction is like the min embedded payload fraction
+** except that it applies to leaf nodes in a LEAFDATA tree.  The maximum
+** payload fraction for a LEAFDATA tree is always 100% (or 255) and it
+** not specified in the header.
+**
+** Each btree pages is divided into three sections:  The header, the
+** cell pointer array, and the cell content area.  Page 1 also has a 100-byte
+** file header that occurs before the page header.
+**
+**      |----------------|
+**      | file header    |   100 bytes.  Page 1 only.
+**      |----------------|
+**      | page header    |   8 bytes for leaves.  12 bytes for interior nodes
+**      |----------------|
+**      | cell pointer   |   |  2 bytes per cell.  Sorted order.
+**      | array          |   |  Grows downward
+**      |                |   v
+**      |----------------|
+**      | unallocated    |
+**      | space          |
+**      |----------------|   ^  Grows upwards
+**      | cell content   |   |  Arbitrary order interspersed with freeblocks.
+**      | area           |   |  and free space fragments.
+**      |----------------|
+**
+** The page headers looks like this:
+**
+**   OFFSET   SIZE     DESCRIPTION
+**      0       1      Flags. 1: intkey, 2: zerodata, 4: leafdata, 8: leaf
+**      1       2      byte offset to the first freeblock
+**      3       2      number of cells on this page
+**      5       2      first byte of the cell content area
+**      7       1      number of fragmented free bytes
+**      8       4      Right child (the Ptr(N) value).  Omitted on leaves.
+**
+** The flags define the format of this btree page.  The leaf flag means that
+** this page has no children.  The zerodata flag means that this page carries
+** only keys and no data.  The intkey flag means that the key is an integer
+** which is stored in the key size entry of the cell header rather than in
+** the payload area.
+**
+** The cell pointer array begins on the first byte after the page header.
+** The cell pointer array contains zero or more 2-byte numbers which are
+** offsets from the beginning of the page to the cell content in the cell
+** content area.  The cell pointers occur in sorted order.  The system strives
+** to keep free space after the last cell pointer so that new cells can
+** be easily added without having to defragment the page.
+**
+** Cell content is stored at the very end of the page and grows toward the
+** beginning of the page.
+**
+** Unused space within the cell content area is collected into a linked list of
+** freeblocks.  Each freeblock is at least 4 bytes in size.  The byte offset
+** to the first freeblock is given in the header.  Freeblocks occur in
+** increasing order.  Because a freeblock must be at least 4 bytes in size,
+** any group of 3 or fewer unused bytes in the cell content area cannot
+** exist on the freeblock chain.  A group of 3 or fewer free bytes is called
+** a fragment.  The total number of bytes in all fragments is recorded.
+** in the page header at offset 7.
+**
+**    SIZE    DESCRIPTION
+**      2     Byte offset of the next freeblock
+**      2     Bytes in this freeblock
+**
+** Cells are of variable length.  Cells are stored in the cell content area at
+** the end of the page.  Pointers to the cells are in the cell pointer array
+** that immediately follows the page header.  Cells is not necessarily
+** contiguous or in order, but cell pointers are contiguous and in order.
+**
+** Cell content makes use of variable length integers.  A variable
+** length integer is 1 to 9 bytes where the lower 7 bits of each
+** byte are used.  The integer consists of all bytes that have bit 8 set and
+** the first byte with bit 8 clear.  The most significant byte of the integer
+** appears first.  A variable-length integer may not be more than 9 bytes long.
+** As a special case, all 8 bits of the 9th byte are used as data.  This
+** allows a 64-bit integer to be encoded in 9 bytes.
+**
+**    0x00                      becomes  0x00000000
+**    0x7f                      becomes  0x0000007f
+**    0x81 0x00                 becomes  0x00000080
+**    0x82 0x00                 becomes  0x00000100
+**    0x80 0x7f                 becomes  0x0000007f
+**    0x81 0x91 0xd1 0xac 0x78  becomes  0x12345678
+**    0x81 0x81 0x81 0x81 0x01  becomes  0x10204081
+**
+** Variable length integers are used for rowids and to hold the number of
+** bytes of key and data in a btree cell.
+**
+** The content of a cell looks like this:
+**
+**    SIZE    DESCRIPTION
+**      4     Page number of the left child. Omitted if leaf flag is set.
+**     var    Number of bytes of data. Omitted if the zerodata flag is set.
+**     var    Number of bytes of key. Or the key itself if intkey flag is set.
+**      *     Payload
+**      4     First page of the overflow chain.  Omitted if no overflow
+**
+** Overflow pages form a linked list.  Each page except the last is completely
+** filled with data (pagesize - 4 bytes).  The last page can have as little
+** as 1 byte of data.
+**
+**    SIZE    DESCRIPTION
+**      4     Page number of next overflow page
+**      *     Data
+**
+** Freelist pages come in two subtypes: trunk pages and leaf pages.  The
+** file header points to the first in a linked list of trunk page.  Each trunk
+** page points to multiple leaf pages.  The content of a leaf page is
+** unspecified.  A trunk page looks like this:
+**
+**    SIZE    DESCRIPTION
+**      4     Page number of next trunk page
+**      4     Number of leaf pointers on this page
+**      *     zero or more pages numbers of leaves
+*/
+/* #include "sqliteInt.h" */
+
+
+/* The following value is the maximum cell size assuming a maximum page
+** size give above.
+*/
+#define MX_CELL_SIZE(pBt)  ((int)(pBt->pageSize-8))
+
+/* The maximum number of cells on a single page of the database.  This
+** assumes a minimum cell size of 6 bytes  (4 bytes for the cell itself
+** plus 2 bytes for the index to the cell in the page header).  Such
+** small cells will be rare, but they are possible.
+*/
+#define MX_CELL(pBt) ((pBt->pageSize-8)/6)
+
+/* Forward declarations */
+typedef struct MemPage MemPage;
+typedef struct BtLock BtLock;
+typedef struct CellInfo CellInfo;
+
+/*
+** This is a magic string that appears at the beginning of every
+** SQLite database in order to identify the file as a real database.
+**
+** You can change this value at compile-time by specifying a
+** -DSQLITE_FILE_HEADER="..." on the compiler command-line.  The
+** header must be exactly 16 bytes including the zero-terminator so
+** the string itself should be 15 characters long.  If you change
+** the header, then your custom library will not be able to read
+** databases generated by the standard tools and the standard tools
+** will not be able to read databases created by your custom library.
+*/
+#ifndef SQLITE_FILE_HEADER /* 123456789 123456 */
+#  define SQLITE_FILE_HEADER "SQLite format 3"
+#endif
+
+/*
+** Page type flags.  An ORed combination of these flags appear as the
+** first byte of on-disk image of every BTree page.
+*/
+#define PTF_INTKEY    0x01
+#define PTF_ZERODATA  0x02
+#define PTF_LEAFDATA  0x04
+#define PTF_LEAF      0x08
+
+/*
+** An instance of this object stores information about each a single database
+** page that has been loaded into memory.  The information in this object
+** is derived from the raw on-disk page content.
+**
+** As each database page is loaded into memory, the pager allocates an
+** instance of this object and zeros the first 8 bytes.  (This is the
+** "extra" information associated with each page of the pager.)
+**
+** Access to all fields of this structure is controlled by the mutex
+** stored in MemPage.pBt->mutex.
+*/
+struct MemPage {
+  u8 isInit;           /* True if previously initialized. MUST BE FIRST! */
+  u8 intKey;           /* True if table b-trees.  False for index b-trees */
+  u8 intKeyLeaf;       /* True if the leaf of an intKey table */
+  Pgno pgno;           /* Page number for this page */
+  /* Only the first 8 bytes (above) are zeroed by pager.c when a new page
+  ** is allocated. All fields that follow must be initialized before use */
+  u8 leaf;             /* True if a leaf page */
+  u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
+  u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */
+  u8 max1bytePayload;  /* min(maxLocal,127) */
+  u8 nOverflow;        /* Number of overflow cell bodies in aCell[] */
+  u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
+  u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
+  u16 cellOffset;      /* Index in aData of first cell pointer */
+  int nFree;           /* Number of free bytes on the page. -1 for unknown */
+  u16 nCell;           /* Number of cells on this page, local and ovfl */
+  u16 maskPage;        /* Mask for page offset */
+  u16 aiOvfl[4];       /* Insert the i-th overflow cell before the aiOvfl-th
+                       ** non-overflow cell */
+  u8 *apOvfl[4];       /* Pointers to the body of overflow cells */
+  BtShared *pBt;       /* Pointer to BtShared that this page is part of */
+  u8 *aData;           /* Pointer to disk image of the page data */
+  u8 *aDataEnd;        /* One byte past the end of the entire page - not just
+                       ** the usable space, the entire page.  Used to prevent
+                       ** corruption-induced buffer overflow. */
+  u8 *aCellIdx;        /* The cell index area */
+  u8 *aDataOfst;       /* Same as aData for leaves.  aData+4 for interior */
+  DbPage *pDbPage;     /* Pager page handle */
+  u16 (*xCellSize)(MemPage*,u8*);             /* cellSizePtr method */
+  void (*xParseCell)(MemPage*,u8*,CellInfo*); /* btreeParseCell method */
+};
+
+/*
+** A linked list of the following structures is stored at BtShared.pLock.
+** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor
+** is opened on the table with root page BtShared.iTable. Locks are removed
+** from this list when a transaction is committed or rolled back, or when
+** a btree handle is closed.
+*/
+struct BtLock {
+  Btree *pBtree;        /* Btree handle holding this lock */
+  Pgno iTable;          /* Root page of table */
+  u8 eLock;             /* READ_LOCK or WRITE_LOCK */
+  BtLock *pNext;        /* Next in BtShared.pLock list */
+};
+
+/* Candidate values for BtLock.eLock */
+#define READ_LOCK     1
+#define WRITE_LOCK    2
+
+/* A Btree handle
+**
+** A database connection contains a pointer to an instance of
+** this object for every database file that it has open.  This structure
+** is opaque to the database connection.  The database connection cannot
+** see the internals of this structure and only deals with pointers to
+** this structure.
+**
+** For some database files, the same underlying database cache might be
+** shared between multiple connections.  In that case, each connection
+** has it own instance of this object.  But each instance of this object
+** points to the same BtShared object.  The database cache and the
+** schema associated with the database file are all contained within
+** the BtShared object.
+**
+** All fields in this structure are accessed under sqlite3.mutex.
+** The pBt pointer itself may not be changed while there exists cursors
+** in the referenced BtShared that point back to this Btree since those
+** cursors have to go through this Btree to find their BtShared and
+** they often do so without holding sqlite3.mutex.
+*/
+struct Btree {
+  sqlite3 *db;       /* The database connection holding this btree */
+  BtShared *pBt;     /* Sharable content of this btree */
+  u8 inTrans;        /* TRANS_NONE, TRANS_READ or TRANS_WRITE */
+  u8 sharable;       /* True if we can share pBt with another db */
+  u8 locked;         /* True if db currently has pBt locked */
+  u8 hasIncrblobCur; /* True if there are one or more Incrblob cursors */
+  int wantToLock;    /* Number of nested calls to sqlite3BtreeEnter() */
+  int nBackup;       /* Number of backup operations reading this btree */
+  u32 iBDataVersion; /* Combines with pBt->pPager->iDataVersion */
+  Btree *pNext;      /* List of other sharable Btrees from the same db */
+  Btree *pPrev;      /* Back pointer of the same list */
+#ifdef SQLITE_DEBUG
+  u64 nSeek;         /* Calls to sqlite3BtreeMovetoUnpacked() */
+#endif
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  BtLock lock;       /* Object used to lock page 1 */
+#endif
+};
+
+/*
+** Btree.inTrans may take one of the following values.
+**
+** If the shared-data extension is enabled, there may be multiple users
+** of the Btree structure. At most one of these may open a write transaction,
+** but any number may have active read transactions.
+**
+** These values must match SQLITE_TXN_NONE, SQLITE_TXN_READ, and
+** SQLITE_TXN_WRITE
+*/
+#define TRANS_NONE  0
+#define TRANS_READ  1
+#define TRANS_WRITE 2
+
+#if TRANS_NONE!=SQLITE_TXN_NONE
+# error wrong numeric code for no-transaction
+#endif
+#if TRANS_READ!=SQLITE_TXN_READ
+# error wrong numeric code for read-transaction
+#endif
+#if TRANS_WRITE!=SQLITE_TXN_WRITE
+# error wrong numeric code for write-transaction
+#endif
+
+
+/*
+** An instance of this object represents a single database file.
+**
+** A single database file can be in use at the same time by two
+** or more database connections.  When two or more connections are
+** sharing the same database file, each connection has it own
+** private Btree object for the file and each of those Btrees points
+** to this one BtShared object.  BtShared.nRef is the number of
+** connections currently sharing this database file.
+**
+** Fields in this structure are accessed under the BtShared.mutex
+** mutex, except for nRef and pNext which are accessed under the
+** global SQLITE_MUTEX_STATIC_MAIN mutex.  The pPager field
+** may not be modified once it is initially set as long as nRef>0.
+** The pSchema field may be set once under BtShared.mutex and
+** thereafter is unchanged as long as nRef>0.
+**
+** isPending:
+**
+**   If a BtShared client fails to obtain a write-lock on a database
+**   table (because there exists one or more read-locks on the table),
+**   the shared-cache enters 'pending-lock' state and isPending is
+**   set to true.
+**
+**   The shared-cache leaves the 'pending lock' state when either of
+**   the following occur:
+**
+**     1) The current writer (BtShared.pWriter) concludes its transaction, OR
+**     2) The number of locks held by other connections drops to zero.
+**
+**   while in the 'pending-lock' state, no connection may start a new
+**   transaction.
+**
+**   This feature is included to help prevent writer-starvation.
+*/
+struct BtShared {
+  Pager *pPager;        /* The page cache */
+  sqlite3 *db;          /* Database connection currently using this Btree */
+  BtCursor *pCursor;    /* A list of all open cursors */
+  MemPage *pPage1;      /* First page of the database */
+  u8 openFlags;         /* Flags to sqlite3BtreeOpen() */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  u8 autoVacuum;        /* True if auto-vacuum is enabled */
+  u8 incrVacuum;        /* True if incr-vacuum is enabled */
+  u8 bDoTruncate;       /* True to truncate db on commit */
+#endif
+  u8 inTransaction;     /* Transaction state */
+  u8 max1bytePayload;   /* Maximum first byte of cell for a 1-byte payload */
+  u8 nReserveWanted;    /* Desired number of extra bytes per page */
+  u16 btsFlags;         /* Boolean parameters.  See BTS_* macros below */
+  u16 maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
+  u16 minLocal;         /* Minimum local payload in non-LEAFDATA tables */
+  u16 maxLeaf;          /* Maximum local payload in a LEAFDATA table */
+  u16 minLeaf;          /* Minimum local payload in a LEAFDATA table */
+  u32 pageSize;         /* Total number of bytes on a page */
+  u32 usableSize;       /* Number of usable bytes on each page */
+  int nTransaction;     /* Number of open transactions (read + write) */
+  u32 nPage;            /* Number of pages in the database */
+  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
+  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
+  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this object */
+  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  int nRef;             /* Number of references to this structure */
+  BtShared *pNext;      /* Next on a list of sharable BtShared structs */
+  BtLock *pLock;        /* List of locks held on this shared-btree struct */
+  Btree *pWriter;       /* Btree with currently open write transaction */
+#endif
+  u8 *pTmpSpace;        /* Temp space sufficient to hold a single cell */
+  int nPreformatSize;   /* Size of last cell written by TransferRow() */
+};
+
+/*
+** Allowed values for BtShared.btsFlags
+*/
+#define BTS_READ_ONLY        0x0001   /* Underlying file is readonly */
+#define BTS_PAGESIZE_FIXED   0x0002   /* Page size can no longer be changed */
+#define BTS_SECURE_DELETE    0x0004   /* PRAGMA secure_delete is enabled */
+#define BTS_OVERWRITE        0x0008   /* Overwrite deleted content with zeros */
+#define BTS_FAST_SECURE      0x000c   /* Combination of the previous two */
+#define BTS_INITIALLY_EMPTY  0x0010   /* Database was empty at trans start */
+#define BTS_NO_WAL           0x0020   /* Do not open write-ahead-log files */
+#define BTS_EXCLUSIVE        0x0040   /* pWriter has an exclusive lock */
+#define BTS_PENDING          0x0080   /* Waiting for read-locks to clear */
+
+/*
+** An instance of the following structure is used to hold information
+** about a cell.  The parseCellPtr() function fills in this structure
+** based on information extract from the raw disk page.
+*/
+struct CellInfo {
+  i64 nKey;      /* The key for INTKEY tables, or nPayload otherwise */
+  u8 *pPayload;  /* Pointer to the start of payload */
+  u32 nPayload;  /* Bytes of payload */
+  u16 nLocal;    /* Amount of payload held locally, not on overflow */
+  u16 nSize;     /* Size of the cell content on the main b-tree page */
+};
+
+/*
+** Maximum depth of an SQLite B-Tree structure. Any B-Tree deeper than
+** this will be declared corrupt. This value is calculated based on a
+** maximum database size of 2^31 pages a minimum fanout of 2 for a
+** root-node and 3 for all other internal nodes.
+**
+** If a tree that appears to be taller than this is encountered, it is
+** assumed that the database is corrupt.
+*/
+#define BTCURSOR_MAX_DEPTH 20
+
+/*
+** A cursor is a pointer to a particular entry within a particular
+** b-tree within a database file.
+**
+** The entry is identified by its MemPage and the index in
+** MemPage.aCell[] of the entry.
+**
+** A single database file can be shared by two more database connections,
+** but cursors cannot be shared.  Each cursor is associated with a
+** particular database connection identified BtCursor.pBtree.db.
+**
+** Fields in this structure are accessed under the BtShared.mutex
+** found at self->pBt->mutex.
+**
+** skipNext meaning:
+** The meaning of skipNext depends on the value of eState:
+**
+**   eState            Meaning of skipNext
+**   VALID             skipNext is meaningless and is ignored
+**   INVALID           skipNext is meaningless and is ignored
+**   SKIPNEXT          sqlite3BtreeNext() is a no-op if skipNext>0 and
+**                     sqlite3BtreePrevious() is no-op if skipNext<0.
+**   REQUIRESEEK       restoreCursorPosition() restores the cursor to
+**                     eState=SKIPNEXT if skipNext!=0
+**   FAULT             skipNext holds the cursor fault error code.
+*/
+struct BtCursor {
+  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
+  u8 curFlags;              /* zero or more BTCF_* flags defined below */
+  u8 curPagerFlags;         /* Flags to send to sqlite3PagerGet() */
+  u8 hints;                 /* As configured by CursorSetHints() */
+  int skipNext;    /* Prev() is noop if negative. Next() is noop if positive.
+                   ** Error code if eState==CURSOR_FAULT */
+  Btree *pBtree;            /* The Btree to which this cursor belongs */
+  Pgno *aOverflow;          /* Cache of overflow page locations */
+  void *pKey;               /* Saved key that was cursor last known position */
+  /* All fields above are zeroed when the cursor is allocated.  See
+  ** sqlite3BtreeCursorZero().  Fields that follow must be manually
+  ** initialized. */
+#define BTCURSOR_FIRST_UNINIT pBt   /* Name of first uninitialized field */
+  BtShared *pBt;            /* The BtShared this cursor points to */
+  BtCursor *pNext;          /* Forms a linked list of all cursors */
+  CellInfo info;            /* A parse of the cell we are pointing at */
+  i64 nKey;                 /* Size of pKey, or last integer key */
+  Pgno pgnoRoot;            /* The root page of this tree */
+  i8 iPage;                 /* Index of current page in apPage */
+  u8 curIntKey;             /* Value of apPage[0]->intKey */
+  u16 ix;                   /* Current index for apPage[iPage] */
+  u16 aiIdx[BTCURSOR_MAX_DEPTH-1];     /* Current index in apPage[i] */
+  struct KeyInfo *pKeyInfo;            /* Arg passed to comparison function */
+  MemPage *pPage;                        /* Current page */
+  MemPage *apPage[BTCURSOR_MAX_DEPTH-1]; /* Stack of parents of current page */
+};
+
+/*
+** Legal values for BtCursor.curFlags
+*/
+#define BTCF_WriteFlag    0x01   /* True if a write cursor */
+#define BTCF_ValidNKey    0x02   /* True if info.nKey is valid */
+#define BTCF_ValidOvfl    0x04   /* True if aOverflow is valid */
+#define BTCF_AtLast       0x08   /* Cursor is pointing to the last entry */
+#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */
+#define BTCF_Multiple     0x20   /* Maybe another cursor on the same btree */
+#define BTCF_Pinned       0x40   /* Cursor is busy and cannot be moved */
+
+/*
+** Potential values for BtCursor.eState.
+**
+** CURSOR_INVALID:
+**   Cursor does not point to a valid entry. This can happen (for example)
+**   because the table is empty or because BtreeCursorFirst() has not been
+**   called.
+**
+** CURSOR_VALID:
+**   Cursor points to a valid entry. getPayload() etc. may be called.
+**
+** CURSOR_SKIPNEXT:
+**   Cursor is valid except that the Cursor.skipNext field is non-zero
+**   indicating that the next sqlite3BtreeNext() or sqlite3BtreePrevious()
+**   operation should be a no-op.
+**
+** CURSOR_REQUIRESEEK:
+**   The table that this cursor was opened on still exists, but has been
+**   modified since the cursor was last used. The cursor position is saved
+**   in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in
+**   this state, restoreCursorPosition() can be called to attempt to
+**   seek the cursor to the saved position.
+**
+** CURSOR_FAULT:
+**   An unrecoverable error (an I/O error or a malloc failure) has occurred
+**   on a different connection that shares the BtShared cache with this
+**   cursor.  The error has left the cache in an inconsistent state.
+**   Do nothing else with this cursor.  Any attempt to use the cursor
+**   should return the error code stored in BtCursor.skipNext
+*/
+#define CURSOR_VALID             0
+#define CURSOR_INVALID           1
+#define CURSOR_SKIPNEXT          2
+#define CURSOR_REQUIRESEEK       3
+#define CURSOR_FAULT             4
+
+/*
+** The database page the PENDING_BYTE occupies. This page is never used.
+*/
+#define PENDING_BYTE_PAGE(pBt)  ((Pgno)((PENDING_BYTE/((pBt)->pageSize))+1))
+
+/*
+** These macros define the location of the pointer-map entry for a
+** database page. The first argument to each is the number of usable
+** bytes on each page of the database (often 1024). The second is the
+** page number to look up in the pointer map.
+**
+** PTRMAP_PAGENO returns the database page number of the pointer-map
+** page that stores the required pointer. PTRMAP_PTROFFSET returns
+** the offset of the requested map entry.
+**
+** If the pgno argument passed to PTRMAP_PAGENO is a pointer-map page,
+** then pgno is returned. So (pgno==PTRMAP_PAGENO(pgsz, pgno)) can be
+** used to test if pgno is a pointer-map page. PTRMAP_ISPAGE implements
+** this test.
+*/
+#define PTRMAP_PAGENO(pBt, pgno) ptrmapPageno(pBt, pgno)
+#define PTRMAP_PTROFFSET(pgptrmap, pgno) (5*(pgno-pgptrmap-1))
+#define PTRMAP_ISPAGE(pBt, pgno) (PTRMAP_PAGENO((pBt),(pgno))==(pgno))
+
+/*
+** The pointer map is a lookup table that identifies the parent page for
+** each child page in the database file.  The parent page is the page that
+** contains a pointer to the child.  Every page in the database contains
+** 0 or 1 parent pages.  (In this context 'database page' refers
+** to any page that is not part of the pointer map itself.)  Each pointer map
+** entry consists of a single byte 'type' and a 4 byte parent page number.
+** The PTRMAP_XXX identifiers below are the valid types.
+**
+** The purpose of the pointer map is to facility moving pages from one
+** position in the file to another as part of autovacuum.  When a page
+** is moved, the pointer in its parent must be updated to point to the
+** new location.  The pointer map is used to locate the parent page quickly.
+**
+** PTRMAP_ROOTPAGE: The database page is a root-page. The page-number is not
+**                  used in this case.
+**
+** PTRMAP_FREEPAGE: The database page is an unused (free) page. The page-number
+**                  is not used in this case.
+**
+** PTRMAP_OVERFLOW1: The database page is the first page in a list of
+**                   overflow pages. The page number identifies the page that
+**                   contains the cell with a pointer to this overflow page.
+**
+** PTRMAP_OVERFLOW2: The database page is the second or later page in a list of
+**                   overflow pages. The page-number identifies the previous
+**                   page in the overflow page list.
+**
+** PTRMAP_BTREE: The database page is a non-root btree page. The page number
+**               identifies the parent page in the btree.
+*/
+#define PTRMAP_ROOTPAGE 1
+#define PTRMAP_FREEPAGE 2
+#define PTRMAP_OVERFLOW1 3
+#define PTRMAP_OVERFLOW2 4
+#define PTRMAP_BTREE 5
+
+/* A bunch of assert() statements to check the transaction state variables
+** of handle p (type Btree*) are internally consistent.
+*/
+#define btreeIntegrity(p) \
+  assert( p->pBt->inTransaction!=TRANS_NONE || p->pBt->nTransaction==0 ); \
+  assert( p->pBt->inTransaction>=p->inTrans );
+
+
+/*
+** The ISAUTOVACUUM macro is used within balance_nonroot() to determine
+** if the database supports auto-vacuum or not. Because it is used
+** within an expression that is an argument to another macro
+** (sqliteMallocRaw), it is not possible to use conditional compilation.
+** So, this macro is defined instead.
+*/
+#ifndef SQLITE_OMIT_AUTOVACUUM
+#define ISAUTOVACUUM(pBt) (pBt->autoVacuum)
+#else
+#define ISAUTOVACUUM(pBt) 0
+#endif
+
+
+/*
+** This structure is passed around through all the PRAGMA integrity_check
+** checking routines in order to keep track of some global state information.
+**
+** The aRef[] array is allocated so that there is 1 bit for each page in
+** the database. As the integrity-check proceeds, for each page used in
+** the database the corresponding bit is set. This allows integrity-check to
+** detect pages that are used twice and orphaned pages (both of which
+** indicate corruption).
+*/
+typedef struct IntegrityCk IntegrityCk;
+struct IntegrityCk {
+  BtShared *pBt;    /* The tree being checked out */
+  Pager *pPager;    /* The associated pager.  Also accessible by pBt->pPager */
+  u8 *aPgRef;       /* 1 bit per page in the db (see above) */
+  Pgno nCkPage;     /* Pages in the database.  0 for partial check */
+  int mxErr;        /* Stop accumulating errors when this reaches zero */
+  int nErr;         /* Number of messages written to zErrMsg so far */
+  int rc;           /* SQLITE_OK, SQLITE_NOMEM, or SQLITE_INTERRUPT */
+  u32 nStep;        /* Number of steps into the integrity_check process */
+  const char *zPfx; /* Error message prefix */
+  Pgno v0;          /* Value for first %u substitution in zPfx (root page) */
+  Pgno v1;          /* Value for second %u substitution in zPfx (current pg) */
+  int v2;           /* Value for third %d substitution in zPfx */
+  StrAccum errMsg;  /* Accumulate the error message text here */
+  u32 *heap;        /* Min-heap used for analyzing cell coverage */
+  sqlite3 *db;      /* Database connection running the check */
+  i64 nRow;         /* Number of rows visited in current tree */
+};
+
+/*
+** Routines to read or write a two- and four-byte big-endian integer values.
+*/
+#define get2byte(x)   ((x)[0]<<8 | (x)[1])
+#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
+#define get4byte sqlite3Get4byte
+#define put4byte sqlite3Put4byte
+
+/*
+** get2byteAligned(), unlike get2byte(), requires that its argument point to a
+** two-byte aligned address.  get2byteAligned() is only used for accessing the
+** cell addresses in a btree header.
+*/
+#if SQLITE_BYTEORDER==4321
+# define get2byteAligned(x)  (*(u16*)(x))
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4008000
+# define get2byteAligned(x)  __builtin_bswap16(*(u16*)(x))
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+# define get2byteAligned(x)  _byteswap_ushort(*(u16*)(x))
+#else
+# define get2byteAligned(x)  ((x)[0]<<8 | (x)[1])
+#endif
+
+/************** End of btreeInt.h ********************************************/
+/************** Continuing where we left off in btmutex.c ********************/
+#ifndef SQLITE_OMIT_SHARED_CACHE
+#if SQLITE_THREADSAFE
+
+/*
+** Obtain the BtShared mutex associated with B-Tree handle p. Also,
+** set BtShared.db to the database handle associated with p and the
+** p->locked boolean to true.
+*/
+static void lockBtreeMutex(Btree *p){
+  assert( p->locked==0 );
+  assert( sqlite3_mutex_notheld(p->pBt->mutex) );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+
+  sqlite3_mutex_enter(p->pBt->mutex);
+  p->pBt->db = p->db;
+  p->locked = 1;
+}
+
+/*
+** Release the BtShared mutex associated with B-Tree handle p and
+** clear the p->locked boolean.
+*/
+static void SQLITE_NOINLINE unlockBtreeMutex(Btree *p){
+  BtShared *pBt = p->pBt;
+  assert( p->locked==1 );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  assert( p->db==pBt->db );
+
+  sqlite3_mutex_leave(pBt->mutex);
+  p->locked = 0;
+}
+
+/* Forward reference */
+static void SQLITE_NOINLINE btreeLockCarefully(Btree *p);
+
+/*
+** Enter a mutex on the given BTree object.
+**
+** If the object is not sharable, then no mutex is ever required
+** and this routine is a no-op.  The underlying mutex is non-recursive.
+** But we keep a reference count in Btree.wantToLock so the behavior
+** of this interface is recursive.
+**
+** To avoid deadlocks, multiple Btrees are locked in the same order
+** by all database connections.  The p->pNext is a list of other
+** Btrees belonging to the same database connection as the p Btree
+** which need to be locked after p.  If we cannot get a lock on
+** p, then first unlock all of the others on p->pNext, then wait
+** for the lock to become available on p, then relock all of the
+** subsequent Btrees that desire a lock.
+*/
+SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
+  /* Some basic sanity checking on the Btree.  The list of Btrees
+  ** connected by pNext and pPrev should be in sorted order by
+  ** Btree.pBt value. All elements of the list should belong to
+  ** the same connection. Only shared Btrees are on the list. */
+  assert( p->pNext==0 || p->pNext->pBt>p->pBt );
+  assert( p->pPrev==0 || p->pPrev->pBt<p->pBt );
+  assert( p->pNext==0 || p->pNext->db==p->db );
+  assert( p->pPrev==0 || p->pPrev->db==p->db );
+  assert( p->sharable || (p->pNext==0 && p->pPrev==0) );
+
+  /* Check for locking consistency */
+  assert( !p->locked || p->wantToLock>0 );
+  assert( p->sharable || p->wantToLock==0 );
+
+  /* We should already hold a lock on the database connection */
+  assert( sqlite3_mutex_held(p->db->mutex) );
+
+  /* Unless the database is sharable and unlocked, then BtShared.db
+  ** should already be set correctly. */
+  assert( (p->locked==0 && p->sharable) || p->pBt->db==p->db );
+
+  if( !p->sharable ) return;
+  p->wantToLock++;
+  if( p->locked ) return;
+  btreeLockCarefully(p);
+}
+
+/* This is a helper function for sqlite3BtreeLock(). By moving
+** complex, but seldom used logic, out of sqlite3BtreeLock() and
+** into this routine, we avoid unnecessary stack pointer changes
+** and thus help the sqlite3BtreeLock() routine to run much faster
+** in the common case.
+*/
+static void SQLITE_NOINLINE btreeLockCarefully(Btree *p){
+  Btree *pLater;
+
+  /* In most cases, we should be able to acquire the lock we
+  ** want without having to go through the ascending lock
+  ** procedure that follows.  Just be sure not to block.
+  */
+  if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
+    p->pBt->db = p->db;
+    p->locked = 1;
+    return;
+  }
+
+  /* To avoid deadlock, first release all locks with a larger
+  ** BtShared address.  Then acquire our lock.  Then reacquire
+  ** the other BtShared locks that we used to hold in ascending
+  ** order.
+  */
+  for(pLater=p->pNext; pLater; pLater=pLater->pNext){
+    assert( pLater->sharable );
+    assert( pLater->pNext==0 || pLater->pNext->pBt>pLater->pBt );
+    assert( !pLater->locked || pLater->wantToLock>0 );
+    if( pLater->locked ){
+      unlockBtreeMutex(pLater);
+    }
+  }
+  lockBtreeMutex(p);
+  for(pLater=p->pNext; pLater; pLater=pLater->pNext){
+    if( pLater->wantToLock ){
+      lockBtreeMutex(pLater);
+    }
+  }
+}
+
+
+/*
+** Exit the recursive mutex on a Btree.
+*/
+SQLITE_PRIVATE void sqlite3BtreeLeave(Btree *p){
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  if( p->sharable ){
+    assert( p->wantToLock>0 );
+    p->wantToLock--;
+    if( p->wantToLock==0 ){
+      unlockBtreeMutex(p);
+    }
+  }
+}
+
+#ifndef NDEBUG
+/*
+** Return true if the BtShared mutex is held on the btree, or if the
+** B-Tree is not marked as sharable.
+**
+** This routine is used only from within assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3BtreeHoldsMutex(Btree *p){
+  assert( p->sharable==0 || p->locked==0 || p->wantToLock>0 );
+  assert( p->sharable==0 || p->locked==0 || p->db==p->pBt->db );
+  assert( p->sharable==0 || p->locked==0 || sqlite3_mutex_held(p->pBt->mutex) );
+  assert( p->sharable==0 || p->locked==0 || sqlite3_mutex_held(p->db->mutex) );
+
+  return (p->sharable==0 || p->locked);
+}
+#endif
+
+
+/*
+** Enter the mutex on every Btree associated with a database
+** connection.  This is needed (for example) prior to parsing
+** a statement since we will be comparing table and column names
+** against all schemas and we do not want those schemas being
+** reset out from under us.
+**
+** There is a corresponding leave-all procedures.
+**
+** Enter the mutexes in ascending order by BtShared pointer address
+** to avoid the possibility of deadlock when two threads with
+** two or more btrees in common both try to lock all their btrees
+** at the same instant.
+*/
+static void SQLITE_NOINLINE btreeEnterAll(sqlite3 *db){
+  int i;
+  int skipOk = 1;
+  Btree *p;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nDb; i++){
+    p = db->aDb[i].pBt;
+    if( p && p->sharable ){
+      sqlite3BtreeEnter(p);
+      skipOk = 0;
+    }
+  }
+  db->noSharedCache = skipOk;
+}
+SQLITE_PRIVATE void sqlite3BtreeEnterAll(sqlite3 *db){
+  if( db->noSharedCache==0 ) btreeEnterAll(db);
+}
+static void SQLITE_NOINLINE btreeLeaveAll(sqlite3 *db){
+  int i;
+  Btree *p;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nDb; i++){
+    p = db->aDb[i].pBt;
+    if( p ) sqlite3BtreeLeave(p);
+  }
+}
+SQLITE_PRIVATE void sqlite3BtreeLeaveAll(sqlite3 *db){
+  if( db->noSharedCache==0 ) btreeLeaveAll(db);
+}
+
+#ifndef NDEBUG
+/*
+** Return true if the current thread holds the database connection
+** mutex and all required BtShared mutexes.
+**
+** This routine is used inside assert() statements only.
+*/
+SQLITE_PRIVATE int sqlite3BtreeHoldsAllMutexes(sqlite3 *db){
+  int i;
+  if( !sqlite3_mutex_held(db->mutex) ){
+    return 0;
+  }
+  for(i=0; i<db->nDb; i++){
+    Btree *p;
+    p = db->aDb[i].pBt;
+    if( p && p->sharable &&
+         (p->wantToLock==0 || !sqlite3_mutex_held(p->pBt->mutex)) ){
+      return 0;
+    }
+  }
+  return 1;
+}
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/*
+** Return true if the correct mutexes are held for accessing the
+** db->aDb[iDb].pSchema structure.  The mutexes required for schema
+** access are:
+**
+**   (1) The mutex on db
+**   (2) if iDb!=1, then the mutex on db->aDb[iDb].pBt.
+**
+** If pSchema is not NULL, then iDb is computed from pSchema and
+** db using sqlite3SchemaToIndex().
+*/
+SQLITE_PRIVATE int sqlite3SchemaMutexHeld(sqlite3 *db, int iDb, Schema *pSchema){
+  Btree *p;
+  assert( db!=0 );
+  if( db->pVfs==0 && db->nDb==0 ) return 1;
+  if( pSchema ) iDb = sqlite3SchemaToIndex(db, pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+  if( !sqlite3_mutex_held(db->mutex) ) return 0;
+  if( iDb==1 ) return 1;
+  p = db->aDb[iDb].pBt;
+  assert( p!=0 );
+  return p->sharable==0 || p->locked==1;
+}
+#endif /* NDEBUG */
+
+#else /* SQLITE_THREADSAFE>0 above.  SQLITE_THREADSAFE==0 below */
+/*
+** The following are special cases for mutex enter routines for use
+** in single threaded applications that use shared cache.  Except for
+** these two routines, all mutex operations are no-ops in that case and
+** are null #defines in btree.h.
+**
+** If shared cache is disabled, then all btree mutex routines, including
+** the ones below, are no-ops and are null #defines in btree.h.
+*/
+
+SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
+  p->pBt->db = p->db;
+}
+SQLITE_PRIVATE void sqlite3BtreeEnterAll(sqlite3 *db){
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Btree *p = db->aDb[i].pBt;
+    if( p ){
+      p->pBt->db = p->db;
+    }
+  }
+}
+#endif /* if SQLITE_THREADSAFE */
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** Enter a mutex on a Btree given a cursor owned by that Btree.
+**
+** These entry points are used by incremental I/O only. Enter() is required
+** any time OMIT_SHARED_CACHE is not defined, regardless of whether or not
+** the build is threadsafe. Leave() is only required by threadsafe builds.
+*/
+SQLITE_PRIVATE void sqlite3BtreeEnterCursor(BtCursor *pCur){
+  sqlite3BtreeEnter(pCur->pBtree);
+}
+# if SQLITE_THREADSAFE
+SQLITE_PRIVATE void sqlite3BtreeLeaveCursor(BtCursor *pCur){
+  sqlite3BtreeLeave(pCur->pBtree);
+}
+# endif
+#endif /* ifndef SQLITE_OMIT_INCRBLOB */
+
+#endif /* ifndef SQLITE_OMIT_SHARED_CACHE */
+
+/************** End of btmutex.c *********************************************/
+/************** Begin file btree.c *******************************************/
+/*
+** 2004 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements an external (disk-based) database using BTrees.
+** See the header comment on "btreeInt.h" for additional information.
+** Including a description of file format and an overview of operation.
+*/
+/* #include "btreeInt.h" */
+
+/*
+** The header string that appears at the beginning of every
+** SQLite database.
+*/
+static const char zMagicHeader[] = SQLITE_FILE_HEADER;
+
+/*
+** Set this global variable to 1 to enable tracing using the TRACE
+** macro.
+*/
+#if 0
+int sqlite3BtreeTrace=1;  /* True to enable tracing */
+# define TRACE(X)  if(sqlite3BtreeTrace){printf X;fflush(stdout);}
+#else
+# define TRACE(X)
+#endif
+
+/*
+** Extract a 2-byte big-endian integer from an array of unsigned bytes.
+** But if the value is zero, make it 65536.
+**
+** This routine is used to extract the "offset to cell content area" value
+** from the header of a btree page.  If the page size is 65536 and the page
+** is empty, the offset should be 65536, but the 2-byte value stores zero.
+** This routine makes the necessary adjustment to 65536.
+*/
+#define get2byteNotZero(X)  (((((int)get2byte(X))-1)&0xffff)+1)
+
+/*
+** Values passed as the 5th argument to allocateBtreePage()
+*/
+#define BTALLOC_ANY   0           /* Allocate any page */
+#define BTALLOC_EXACT 1           /* Allocate exact page if possible */
+#define BTALLOC_LE    2           /* Allocate any page <= the parameter */
+
+/*
+** Macro IfNotOmitAV(x) returns (x) if SQLITE_OMIT_AUTOVACUUM is not
+** defined, or 0 if it is. For example:
+**
+**   bIncrVacuum = IfNotOmitAV(pBtShared->incrVacuum);
+*/
+#ifndef SQLITE_OMIT_AUTOVACUUM
+#define IfNotOmitAV(expr) (expr)
+#else
+#define IfNotOmitAV(expr) 0
+#endif
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** A list of BtShared objects that are eligible for participation
+** in shared cache.  This variable has file scope during normal builds,
+** but the test harness needs to access it so we make it global for
+** test builds.
+**
+** Access to this variable is protected by SQLITE_MUTEX_STATIC_MAIN.
+*/
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
+#else
+static BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
+#endif
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Enable or disable the shared pager and schema features.
+**
+** This routine has no effect on existing database connections.
+** The shared cache setting effects only future calls to
+** sqlite3_open(), sqlite3_open16(), or sqlite3_open_v2().
+*/
+SQLITE_API int sqlite3_enable_shared_cache(int enable){
+  sqlite3GlobalConfig.sharedCacheEnabled = enable;
+  return SQLITE_OK;
+}
+#endif
+
+
+
+#ifdef SQLITE_OMIT_SHARED_CACHE
+  /*
+  ** The functions querySharedCacheTableLock(), setSharedCacheTableLock(),
+  ** and clearAllSharedCacheTableLocks()
+  ** manipulate entries in the BtShared.pLock linked list used to store
+  ** shared-cache table level locks. If the library is compiled with the
+  ** shared-cache feature disabled, then there is only ever one user
+  ** of each BtShared structure and so this locking is not necessary.
+  ** So define the lock related functions as no-ops.
+  */
+  #define querySharedCacheTableLock(a,b,c) SQLITE_OK
+  #define setSharedCacheTableLock(a,b,c) SQLITE_OK
+  #define clearAllSharedCacheTableLocks(a)
+  #define downgradeAllSharedCacheTableLocks(a)
+  #define hasSharedCacheTableLock(a,b,c,d) 1
+  #define hasReadConflicts(a, b) 0
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Return and reset the seek counter for a Btree object.
+*/
+SQLITE_PRIVATE sqlite3_uint64 sqlite3BtreeSeekCount(Btree *pBt){
+  u64 n =  pBt->nSeek;
+  pBt->nSeek = 0;
+  return n;
+}
+#endif
+
+/*
+** Implementation of the SQLITE_CORRUPT_PAGE() macro. Takes a single
+** (MemPage*) as an argument. The (MemPage*) must not be NULL.
+**
+** If SQLITE_DEBUG is not defined, then this macro is equivalent to
+** SQLITE_CORRUPT_BKPT. Or, if SQLITE_DEBUG is set, then the log message
+** normally produced as a side-effect of SQLITE_CORRUPT_BKPT is augmented
+** with the page number and filename associated with the (MemPage*).
+*/
+#ifdef SQLITE_DEBUG
+int corruptPageError(int lineno, MemPage *p){
+  char *zMsg;
+  sqlite3BeginBenignMalloc();
+  zMsg = sqlite3_mprintf("database corruption page %u of %s",
+             p->pgno, sqlite3PagerFilename(p->pBt->pPager, 0)
+  );
+  sqlite3EndBenignMalloc();
+  if( zMsg ){
+    sqlite3ReportError(SQLITE_CORRUPT, lineno, zMsg);
+  }
+  sqlite3_free(zMsg);
+  return SQLITE_CORRUPT_BKPT;
+}
+# define SQLITE_CORRUPT_PAGE(pMemPage) corruptPageError(__LINE__, pMemPage)
+#else
+# define SQLITE_CORRUPT_PAGE(pMemPage) SQLITE_CORRUPT_PGNO(pMemPage->pgno)
+#endif
+
+/* Default value for SHARED_LOCK_TRACE macro if shared-cache is disabled
+** or if the lock tracking is disabled.  This is always the value for
+** release builds.
+*/
+#define SHARED_LOCK_TRACE(X,MSG,TAB,TYPE)  /*no-op*/
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+
+#if 0
+/*  ^----  Change to 1 and recompile to enable shared-lock tracing
+**         for debugging purposes.
+**
+** Print all shared-cache locks on a BtShared.  Debugging use only.
+*/
+static void sharedLockTrace(
+  BtShared *pBt,
+  const char *zMsg,
+  int iRoot,
+  int eLockType
+){
+  BtLock *pLock;
+  if( iRoot>0 ){
+    printf("%s-%p %u%s:", zMsg, pBt, iRoot, eLockType==READ_LOCK?"R":"W");
+  }else{
+    printf("%s-%p:", zMsg, pBt);
+  }
+  for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
+    printf(" %p/%u%s", pLock->pBtree, pLock->iTable,
+           pLock->eLock==READ_LOCK ? "R" : "W");
+    while( pLock->pNext && pLock->pBtree==pLock->pNext->pBtree ){
+      pLock = pLock->pNext;
+      printf(",%u%s", pLock->iTable, pLock->eLock==READ_LOCK ? "R" : "W");
+    }
+  }
+  printf("\n");
+  fflush(stdout);
+}
+#undef SHARED_LOCK_TRACE
+#define SHARED_LOCK_TRACE(X,MSG,TAB,TYPE)  sharedLockTrace(X,MSG,TAB,TYPE)
+#endif /* Shared-lock tracing */
+
+#ifdef SQLITE_DEBUG
+/*
+**** This function is only used as part of an assert() statement. ***
+**
+** Check to see if pBtree holds the required locks to read or write to the
+** table with root page iRoot.   Return 1 if it does and 0 if not.
+**
+** For example, when writing to a table with root-page iRoot via
+** Btree connection pBtree:
+**
+**    assert( hasSharedCacheTableLock(pBtree, iRoot, 0, WRITE_LOCK) );
+**
+** When writing to an index that resides in a sharable database, the
+** caller should have first obtained a lock specifying the root page of
+** the corresponding table. This makes things a bit more complicated,
+** as this module treats each table as a separate structure. To determine
+** the table corresponding to the index being written, this
+** function has to search through the database schema.
+**
+** Instead of a lock on the table/index rooted at page iRoot, the caller may
+** hold a write-lock on the schema table (root page 1). This is also
+** acceptable.
+*/
+static int hasSharedCacheTableLock(
+  Btree *pBtree,         /* Handle that must hold lock */
+  Pgno iRoot,            /* Root page of b-tree */
+  int isIndex,           /* True if iRoot is the root of an index b-tree */
+  int eLockType          /* Required lock type (READ_LOCK or WRITE_LOCK) */
+){
+  Schema *pSchema = (Schema *)pBtree->pBt->pSchema;
+  Pgno iTab = 0;
+  BtLock *pLock;
+
+  /* If this database is not shareable, or if the client is reading
+  ** and has the read-uncommitted flag set, then no lock is required.
+  ** Return true immediately.
+  */
+  if( (pBtree->sharable==0)
+   || (eLockType==READ_LOCK && (pBtree->db->flags & SQLITE_ReadUncommit))
+  ){
+    return 1;
+  }
+
+  /* If the client is reading  or writing an index and the schema is
+  ** not loaded, then it is too difficult to actually check to see if
+  ** the correct locks are held.  So do not bother - just return true.
+  ** This case does not come up very often anyhow.
+  */
+  if( isIndex && (!pSchema || (pSchema->schemaFlags&DB_SchemaLoaded)==0) ){
+    return 1;
+  }
+
+  /* Figure out the root-page that the lock should be held on. For table
+  ** b-trees, this is just the root page of the b-tree being read or
+  ** written. For index b-trees, it is the root page of the associated
+  ** table.  */
+  if( isIndex ){
+    HashElem *p;
+    int bSeen = 0;
+    for(p=sqliteHashFirst(&pSchema->idxHash); p; p=sqliteHashNext(p)){
+      Index *pIdx = (Index *)sqliteHashData(p);
+      if( pIdx->tnum==iRoot ){
+        if( bSeen ){
+          /* Two or more indexes share the same root page.  There must
+          ** be imposter tables.  So just return true.  The assert is not
+          ** useful in that case. */
+          return 1;
+        }
+        iTab = pIdx->pTable->tnum;
+        bSeen = 1;
+      }
+    }
+  }else{
+    iTab = iRoot;
+  }
+
+  SHARED_LOCK_TRACE(pBtree->pBt,"hasLock",iRoot,eLockType);
+
+  /* Search for the required lock. Either a write-lock on root-page iTab, a
+  ** write-lock on the schema table, or (if the client is reading) a
+  ** read-lock on iTab will suffice. Return 1 if any of these are found.  */
+  for(pLock=pBtree->pBt->pLock; pLock; pLock=pLock->pNext){
+    if( pLock->pBtree==pBtree
+     && (pLock->iTable==iTab || (pLock->eLock==WRITE_LOCK && pLock->iTable==1))
+     && pLock->eLock>=eLockType
+    ){
+      return 1;
+    }
+  }
+
+  /* Failed to find the required lock. */
+  return 0;
+}
+#endif /* SQLITE_DEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+**** This function may be used as part of assert() statements only. ****
+**
+** Return true if it would be illegal for pBtree to write into the
+** table or index rooted at iRoot because other shared connections are
+** simultaneously reading that same table or index.
+**
+** It is illegal for pBtree to write if some other Btree object that
+** shares the same BtShared object is currently reading or writing
+** the iRoot table.  Except, if the other Btree object has the
+** read-uncommitted flag set, then it is OK for the other object to
+** have a read cursor.
+**
+** For example, before writing to any part of the table or index
+** rooted at page iRoot, one should call:
+**
+**    assert( !hasReadConflicts(pBtree, iRoot) );
+*/
+static int hasReadConflicts(Btree *pBtree, Pgno iRoot){
+  BtCursor *p;
+  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
+    if( p->pgnoRoot==iRoot
+     && p->pBtree!=pBtree
+     && 0==(p->pBtree->db->flags & SQLITE_ReadUncommit)
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+#endif    /* #ifdef SQLITE_DEBUG */
+
+/*
+** Query to see if Btree handle p may obtain a lock of type eLock
+** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
+** SQLITE_OK if the lock may be obtained (by calling
+** setSharedCacheTableLock()), or SQLITE_LOCKED if not.
+*/
+static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){
+  BtShared *pBt = p->pBt;
+  BtLock *pIter;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
+  assert( p->db!=0 );
+  assert( !(p->db->flags&SQLITE_ReadUncommit)||eLock==WRITE_LOCK||iTab==1 );
+
+  /* If requesting a write-lock, then the Btree must have an open write
+  ** transaction on this file. And, obviously, for this to be so there
+  ** must be an open write transaction on the file itself.
+  */
+  assert( eLock==READ_LOCK || (p==pBt->pWriter && p->inTrans==TRANS_WRITE) );
+  assert( eLock==READ_LOCK || pBt->inTransaction==TRANS_WRITE );
+
+  /* This routine is a no-op if the shared-cache is not enabled */
+  if( !p->sharable ){
+    return SQLITE_OK;
+  }
+
+  /* If some other connection is holding an exclusive lock, the
+  ** requested lock may not be obtained.
+  */
+  if( pBt->pWriter!=p && (pBt->btsFlags & BTS_EXCLUSIVE)!=0 ){
+    sqlite3ConnectionBlocked(p->db, pBt->pWriter->db);
+    return SQLITE_LOCKED_SHAREDCACHE;
+  }
+
+  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+    /* The condition (pIter->eLock!=eLock) in the following if(...)
+    ** statement is a simplification of:
+    **
+    **   (eLock==WRITE_LOCK || pIter->eLock==WRITE_LOCK)
+    **
+    ** since we know that if eLock==WRITE_LOCK, then no other connection
+    ** may hold a WRITE_LOCK on any table in this file (since there can
+    ** only be a single writer).
+    */
+    assert( pIter->eLock==READ_LOCK || pIter->eLock==WRITE_LOCK );
+    assert( eLock==READ_LOCK || pIter->pBtree==p || pIter->eLock==READ_LOCK);
+    if( pIter->pBtree!=p && pIter->iTable==iTab && pIter->eLock!=eLock ){
+      sqlite3ConnectionBlocked(p->db, pIter->pBtree->db);
+      if( eLock==WRITE_LOCK ){
+        assert( p==pBt->pWriter );
+        pBt->btsFlags |= BTS_PENDING;
+      }
+      return SQLITE_LOCKED_SHAREDCACHE;
+    }
+  }
+  return SQLITE_OK;
+}
+#endif /* !SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Add a lock on the table with root-page iTable to the shared-btree used
+** by Btree handle p. Parameter eLock must be either READ_LOCK or
+** WRITE_LOCK.
+**
+** This function assumes the following:
+**
+**   (a) The specified Btree object p is connected to a sharable
+**       database (one with the BtShared.sharable flag set), and
+**
+**   (b) No other Btree objects hold a lock that conflicts
+**       with the requested lock (i.e. querySharedCacheTableLock() has
+**       already been called and returned SQLITE_OK).
+**
+** SQLITE_OK is returned if the lock is added successfully. SQLITE_NOMEM
+** is returned if a malloc attempt fails.
+*/
+static int setSharedCacheTableLock(Btree *p, Pgno iTable, u8 eLock){
+  BtShared *pBt = p->pBt;
+  BtLock *pLock = 0;
+  BtLock *pIter;
+
+  SHARED_LOCK_TRACE(pBt,"setLock", iTable, eLock);
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
+  assert( p->db!=0 );
+
+  /* A connection with the read-uncommitted flag set will never try to
+  ** obtain a read-lock using this function. The only read-lock obtained
+  ** by a connection in read-uncommitted mode is on the sqlite_schema
+  ** table, and that lock is obtained in BtreeBeginTrans().  */
+  assert( 0==(p->db->flags&SQLITE_ReadUncommit) || eLock==WRITE_LOCK );
+
+  /* This function should only be called on a sharable b-tree after it
+  ** has been determined that no other b-tree holds a conflicting lock.  */
+  assert( p->sharable );
+  assert( SQLITE_OK==querySharedCacheTableLock(p, iTable, eLock) );
+
+  /* First search the list for an existing lock on this table. */
+  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+    if( pIter->iTable==iTable && pIter->pBtree==p ){
+      pLock = pIter;
+      break;
+    }
+  }
+
+  /* If the above search did not find a BtLock struct associating Btree p
+  ** with table iTable, allocate one and link it into the list.
+  */
+  if( !pLock ){
+    pLock = (BtLock *)sqlite3MallocZero(sizeof(BtLock));
+    if( !pLock ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    pLock->iTable = iTable;
+    pLock->pBtree = p;
+    pLock->pNext = pBt->pLock;
+    pBt->pLock = pLock;
+  }
+
+  /* Set the BtLock.eLock variable to the maximum of the current lock
+  ** and the requested lock. This means if a write-lock was already held
+  ** and a read-lock requested, we don't incorrectly downgrade the lock.
+  */
+  assert( WRITE_LOCK>READ_LOCK );
+  if( eLock>pLock->eLock ){
+    pLock->eLock = eLock;
+  }
+
+  return SQLITE_OK;
+}
+#endif /* !SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Release all the table locks (locks obtained via calls to
+** the setSharedCacheTableLock() procedure) held by Btree object p.
+**
+** This function assumes that Btree p has an open read or write
+** transaction. If it does not, then the BTS_PENDING flag
+** may be incorrectly cleared.
+*/
+static void clearAllSharedCacheTableLocks(Btree *p){
+  BtShared *pBt = p->pBt;
+  BtLock **ppIter = &pBt->pLock;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( p->sharable || 0==*ppIter );
+  assert( p->inTrans>0 );
+
+  SHARED_LOCK_TRACE(pBt, "clearAllLocks", 0, 0);
+
+  while( *ppIter ){
+    BtLock *pLock = *ppIter;
+    assert( (pBt->btsFlags & BTS_EXCLUSIVE)==0 || pBt->pWriter==pLock->pBtree );
+    assert( pLock->pBtree->inTrans>=pLock->eLock );
+    if( pLock->pBtree==p ){
+      *ppIter = pLock->pNext;
+      assert( pLock->iTable!=1 || pLock==&p->lock );
+      if( pLock->iTable!=1 ){
+        sqlite3_free(pLock);
+      }
+    }else{
+      ppIter = &pLock->pNext;
+    }
+  }
+
+  assert( (pBt->btsFlags & BTS_PENDING)==0 || pBt->pWriter );
+  if( pBt->pWriter==p ){
+    pBt->pWriter = 0;
+    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
+  }else if( pBt->nTransaction==2 ){
+    /* This function is called when Btree p is concluding its
+    ** transaction. If there currently exists a writer, and p is not
+    ** that writer, then the number of locks held by connections other
+    ** than the writer must be about to drop to zero. In this case
+    ** set the BTS_PENDING flag to 0.
+    **
+    ** If there is not currently a writer, then BTS_PENDING must
+    ** be zero already. So this next line is harmless in that case.
+    */
+    pBt->btsFlags &= ~BTS_PENDING;
+  }
+}
+
+/*
+** This function changes all write-locks held by Btree p into read-locks.
+*/
+static void downgradeAllSharedCacheTableLocks(Btree *p){
+  BtShared *pBt = p->pBt;
+
+  SHARED_LOCK_TRACE(pBt, "downgradeLocks", 0, 0);
+
+  if( pBt->pWriter==p ){
+    BtLock *pLock;
+    pBt->pWriter = 0;
+    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
+    for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
+      assert( pLock->eLock==READ_LOCK || pLock->pBtree==p );
+      pLock->eLock = READ_LOCK;
+    }
+  }
+}
+
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+
+static void releasePage(MemPage *pPage);         /* Forward reference */
+static void releasePageOne(MemPage *pPage);      /* Forward reference */
+static void releasePageNotNull(MemPage *pPage);  /* Forward reference */
+
+/*
+***** This routine is used inside of assert() only ****
+**
+** Verify that the cursor holds the mutex on its BtShared
+*/
+#ifdef SQLITE_DEBUG
+static int cursorHoldsMutex(BtCursor *p){
+  return sqlite3_mutex_held(p->pBt->mutex);
+}
+
+/* Verify that the cursor and the BtShared agree about what is the current
+** database connetion. This is important in shared-cache mode. If the database
+** connection pointers get out-of-sync, it is possible for routines like
+** btreeInitPage() to reference an stale connection pointer that references a
+** a connection that has already closed.  This routine is used inside assert()
+** statements only and for the purpose of double-checking that the btree code
+** does keep the database connection pointers up-to-date.
+*/
+static int cursorOwnsBtShared(BtCursor *p){
+  assert( cursorHoldsMutex(p) );
+  return (p->pBtree->db==p->pBt->db);
+}
+#endif
+
+/*
+** Invalidate the overflow cache of the cursor passed as the first argument.
+** on the shared btree structure pBt.
+*/
+#define invalidateOverflowCache(pCur) (pCur->curFlags &= ~BTCF_ValidOvfl)
+
+/*
+** Invalidate the overflow page-list cache for all cursors opened
+** on the shared btree structure pBt.
+*/
+static void invalidateAllOverflowCache(BtShared *pBt){
+  BtCursor *p;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  for(p=pBt->pCursor; p; p=p->pNext){
+    invalidateOverflowCache(p);
+  }
+}
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** This function is called before modifying the contents of a table
+** to invalidate any incrblob cursors that are open on the
+** row or one of the rows being modified.
+**
+** If argument isClearTable is true, then the entire contents of the
+** table is about to be deleted. In this case invalidate all incrblob
+** cursors open on any row within the table with root-page pgnoRoot.
+**
+** Otherwise, if argument isClearTable is false, then the row with
+** rowid iRow is being replaced or deleted. In this case invalidate
+** only those incrblob cursors open on that specific row.
+*/
+static void invalidateIncrblobCursors(
+  Btree *pBtree,          /* The database file to check */
+  Pgno pgnoRoot,          /* The table that might be changing */
+  i64 iRow,               /* The rowid that might be changing */
+  int isClearTable        /* True if all rows are being deleted */
+){
+  BtCursor *p;
+  assert( pBtree->hasIncrblobCur );
+  assert( sqlite3BtreeHoldsMutex(pBtree) );
+  pBtree->hasIncrblobCur = 0;
+  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
+    if( (p->curFlags & BTCF_Incrblob)!=0 ){
+      pBtree->hasIncrblobCur = 1;
+      if( p->pgnoRoot==pgnoRoot && (isClearTable || p->info.nKey==iRow) ){
+        p->eState = CURSOR_INVALID;
+      }
+    }
+  }
+}
+
+#else
+  /* Stub function when INCRBLOB is omitted */
+  #define invalidateIncrblobCursors(w,x,y,z)
+#endif /* SQLITE_OMIT_INCRBLOB */
+
+/*
+** Set bit pgno of the BtShared.pHasContent bitvec. This is called
+** when a page that previously contained data becomes a free-list leaf
+** page.
+**
+** The BtShared.pHasContent bitvec exists to work around an obscure
+** bug caused by the interaction of two useful IO optimizations surrounding
+** free-list leaf pages:
+**
+**   1) When all data is deleted from a page and the page becomes
+**      a free-list leaf page, the page is not written to the database
+**      (as free-list leaf pages contain no meaningful data). Sometimes
+**      such a page is not even journalled (as it will not be modified,
+**      why bother journalling it?).
+**
+**   2) When a free-list leaf page is reused, its content is not read
+**      from the database or written to the journal file (why should it
+**      be, if it is not at all meaningful?).
+**
+** By themselves, these optimizations work fine and provide a handy
+** performance boost to bulk delete or insert operations. However, if
+** a page is moved to the free-list and then reused within the same
+** transaction, a problem comes up. If the page is not journalled when
+** it is moved to the free-list and it is also not journalled when it
+** is extracted from the free-list and reused, then the original data
+** may be lost. In the event of a rollback, it may not be possible
+** to restore the database to its original configuration.
+**
+** The solution is the BtShared.pHasContent bitvec. Whenever a page is
+** moved to become a free-list leaf page, the corresponding bit is
+** set in the bitvec. Whenever a leaf page is extracted from the free-list,
+** optimization 2 above is omitted if the corresponding bit is already
+** set in BtShared.pHasContent. The contents of the bitvec are cleared
+** at the end of every transaction.
+*/
+static int btreeSetHasContent(BtShared *pBt, Pgno pgno){
+  int rc = SQLITE_OK;
+  if( !pBt->pHasContent ){
+    assert( pgno<=pBt->nPage );
+    pBt->pHasContent = sqlite3BitvecCreate(pBt->nPage);
+    if( !pBt->pHasContent ){
+      rc = SQLITE_NOMEM_BKPT;
+    }
+  }
+  if( rc==SQLITE_OK && pgno<=sqlite3BitvecSize(pBt->pHasContent) ){
+    rc = sqlite3BitvecSet(pBt->pHasContent, pgno);
+  }
+  return rc;
+}
+
+/*
+** Query the BtShared.pHasContent vector.
+**
+** This function is called when a free-list leaf page is removed from the
+** free-list for reuse. It returns false if it is safe to retrieve the
+** page from the pager layer with the 'no-content' flag set. True otherwise.
+*/
+static int btreeGetHasContent(BtShared *pBt, Pgno pgno){
+  Bitvec *p = pBt->pHasContent;
+  return p && (pgno>sqlite3BitvecSize(p) || sqlite3BitvecTestNotNull(p, pgno));
+}
+
+/*
+** Clear (destroy) the BtShared.pHasContent bitvec. This should be
+** invoked at the conclusion of each write-transaction.
+*/
+static void btreeClearHasContent(BtShared *pBt){
+  sqlite3BitvecDestroy(pBt->pHasContent);
+  pBt->pHasContent = 0;
+}
+
+/*
+** Release all of the apPage[] pages for a cursor.
+*/
+static void btreeReleaseAllCursorPages(BtCursor *pCur){
+  int i;
+  if( pCur->iPage>=0 ){
+    for(i=0; i<pCur->iPage; i++){
+      releasePageNotNull(pCur->apPage[i]);
+    }
+    releasePageNotNull(pCur->pPage);
+    pCur->iPage = -1;
+  }
+}
+
+/*
+** The cursor passed as the only argument must point to a valid entry
+** when this function is called (i.e. have eState==CURSOR_VALID). This
+** function saves the current cursor key in variables pCur->nKey and
+** pCur->pKey. SQLITE_OK is returned if successful or an SQLite error
+** code otherwise.
+**
+** If the cursor is open on an intkey table, then the integer key
+** (the rowid) is stored in pCur->nKey and pCur->pKey is left set to
+** NULL. If the cursor is open on a non-intkey table, then pCur->pKey is
+** set to point to a malloced buffer pCur->nKey bytes in size containing
+** the key.
+*/
+static int saveCursorKey(BtCursor *pCur){
+  int rc = SQLITE_OK;
+  assert( CURSOR_VALID==pCur->eState );
+  assert( 0==pCur->pKey );
+  assert( cursorHoldsMutex(pCur) );
+
+  if( pCur->curIntKey ){
+    /* Only the rowid is required for a table btree */
+    pCur->nKey = sqlite3BtreeIntegerKey(pCur);
+  }else{
+    /* For an index btree, save the complete key content. It is possible
+    ** that the current key is corrupt. In that case, it is possible that
+    ** the sqlite3VdbeRecordUnpack() function may overread the buffer by
+    ** up to the size of 1 varint plus 1 8-byte value when the cursor
+    ** position is restored. Hence the 17 bytes of padding allocated
+    ** below. */
+    void *pKey;
+    pCur->nKey = sqlite3BtreePayloadSize(pCur);
+    pKey = sqlite3Malloc( pCur->nKey + 9 + 8 );
+    if( pKey ){
+      rc = sqlite3BtreePayload(pCur, 0, (int)pCur->nKey, pKey);
+      if( rc==SQLITE_OK ){
+        memset(((u8*)pKey)+pCur->nKey, 0, 9+8);
+        pCur->pKey = pKey;
+      }else{
+        sqlite3_free(pKey);
+      }
+    }else{
+      rc = SQLITE_NOMEM_BKPT;
+    }
+  }
+  assert( !pCur->curIntKey || !pCur->pKey );
+  return rc;
+}
+
+/*
+** Save the current cursor position in the variables BtCursor.nKey
+** and BtCursor.pKey. The cursor's state is set to CURSOR_REQUIRESEEK.
+**
+** The caller must ensure that the cursor is valid (has eState==CURSOR_VALID)
+** prior to calling this routine.
+*/
+static int saveCursorPosition(BtCursor *pCur){
+  int rc;
+
+  assert( CURSOR_VALID==pCur->eState || CURSOR_SKIPNEXT==pCur->eState );
+  assert( 0==pCur->pKey );
+  assert( cursorHoldsMutex(pCur) );
+
+  if( pCur->curFlags & BTCF_Pinned ){
+    return SQLITE_CONSTRAINT_PINNED;
+  }
+  if( pCur->eState==CURSOR_SKIPNEXT ){
+    pCur->eState = CURSOR_VALID;
+  }else{
+    pCur->skipNext = 0;
+  }
+
+  rc = saveCursorKey(pCur);
+  if( rc==SQLITE_OK ){
+    btreeReleaseAllCursorPages(pCur);
+    pCur->eState = CURSOR_REQUIRESEEK;
+  }
+
+  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl|BTCF_AtLast);
+  return rc;
+}
+
+/* Forward reference */
+static int SQLITE_NOINLINE saveCursorsOnList(BtCursor*,Pgno,BtCursor*);
+
+/*
+** Save the positions of all cursors (except pExcept) that are open on
+** the table with root-page iRoot.  "Saving the cursor position" means that
+** the location in the btree is remembered in such a way that it can be
+** moved back to the same spot after the btree has been modified.  This
+** routine is called just before cursor pExcept is used to modify the
+** table, for example in BtreeDelete() or BtreeInsert().
+**
+** If there are two or more cursors on the same btree, then all such
+** cursors should have their BTCF_Multiple flag set.  The btreeCursor()
+** routine enforces that rule.  This routine only needs to be called in
+** the uncommon case when pExpect has the BTCF_Multiple flag set.
+**
+** If pExpect!=NULL and if no other cursors are found on the same root-page,
+** then the BTCF_Multiple flag on pExpect is cleared, to avoid another
+** pointless call to this routine.
+**
+** Implementation note:  This routine merely checks to see if any cursors
+** need to be saved.  It calls out to saveCursorsOnList() in the (unusual)
+** event that cursors are in need to being saved.
+*/
+static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
+  BtCursor *p;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pExcept==0 || pExcept->pBt==pBt );
+  for(p=pBt->pCursor; p; p=p->pNext){
+    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ) break;
+  }
+  if( p ) return saveCursorsOnList(p, iRoot, pExcept);
+  if( pExcept ) pExcept->curFlags &= ~BTCF_Multiple;
+  return SQLITE_OK;
+}
+
+/* This helper routine to saveAllCursors does the actual work of saving
+** the cursors if and when a cursor is found that actually requires saving.
+** The common case is that no cursors need to be saved, so this routine is
+** broken out from its caller to avoid unnecessary stack pointer movement.
+*/
+static int SQLITE_NOINLINE saveCursorsOnList(
+  BtCursor *p,         /* The first cursor that needs saving */
+  Pgno iRoot,          /* Only save cursor with this iRoot. Save all if zero */
+  BtCursor *pExcept    /* Do not save this cursor */
+){
+  do{
+    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ){
+      if( p->eState==CURSOR_VALID || p->eState==CURSOR_SKIPNEXT ){
+        int rc = saveCursorPosition(p);
+        if( SQLITE_OK!=rc ){
+          return rc;
+        }
+      }else{
+        testcase( p->iPage>=0 );
+        btreeReleaseAllCursorPages(p);
+      }
+    }
+    p = p->pNext;
+  }while( p );
+  return SQLITE_OK;
+}
+
+/*
+** Clear the current cursor position.
+*/
+SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  sqlite3_free(pCur->pKey);
+  pCur->pKey = 0;
+  pCur->eState = CURSOR_INVALID;
+}
+
+/*
+** In this version of BtreeMoveto, pKey is a packed index record
+** such as is generated by the OP_MakeRecord opcode.  Unpack the
+** record and then call sqlite3BtreeIndexMoveto() to do the work.
+*/
+static int btreeMoveto(
+  BtCursor *pCur,     /* Cursor open on the btree to be searched */
+  const void *pKey,   /* Packed key if the btree is an index */
+  i64 nKey,           /* Integer key for tables.  Size of pKey for indices */
+  int bias,           /* Bias search to the high end */
+  int *pRes           /* Write search results here */
+){
+  int rc;                    /* Status code */
+  UnpackedRecord *pIdxKey;   /* Unpacked index key */
+
+  if( pKey ){
+    KeyInfo *pKeyInfo = pCur->pKeyInfo;
+    assert( nKey==(i64)(int)nKey );
+    pIdxKey = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
+    if( pIdxKey==0 ) return SQLITE_NOMEM_BKPT;
+    sqlite3VdbeRecordUnpack(pKeyInfo, (int)nKey, pKey, pIdxKey);
+    if( pIdxKey->nField==0 || pIdxKey->nField>pKeyInfo->nAllField ){
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      rc = sqlite3BtreeIndexMoveto(pCur, pIdxKey, pRes);
+    }
+    sqlite3DbFree(pCur->pKeyInfo->db, pIdxKey);
+  }else{
+    pIdxKey = 0;
+    rc = sqlite3BtreeTableMoveto(pCur, nKey, bias, pRes);
+  }
+  return rc;
+}
+
+/*
+** Restore the cursor to the position it was in (or as close to as possible)
+** when saveCursorPosition() was called. Note that this call deletes the
+** saved position info stored by saveCursorPosition(), so there can be
+** at most one effective restoreCursorPosition() call after each
+** saveCursorPosition().
+*/
+static int btreeRestoreCursorPosition(BtCursor *pCur){
+  int rc;
+  int skipNext = 0;
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState>=CURSOR_REQUIRESEEK );
+  if( pCur->eState==CURSOR_FAULT ){
+    return pCur->skipNext;
+  }
+  pCur->eState = CURSOR_INVALID;
+  if( sqlite3FaultSim(410) ){
+    rc = SQLITE_IOERR;
+  }else{
+    rc = btreeMoveto(pCur, pCur->pKey, pCur->nKey, 0, &skipNext);
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3_free(pCur->pKey);
+    pCur->pKey = 0;
+    assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_INVALID );
+    if( skipNext ) pCur->skipNext = skipNext;
+    if( pCur->skipNext && pCur->eState==CURSOR_VALID ){
+      pCur->eState = CURSOR_SKIPNEXT;
+    }
+  }
+  return rc;
+}
+
+#define restoreCursorPosition(p) \
+  (p->eState>=CURSOR_REQUIRESEEK ? \
+         btreeRestoreCursorPosition(p) : \
+         SQLITE_OK)
+
+/*
+** Determine whether or not a cursor has moved from the position where
+** it was last placed, or has been invalidated for any other reason.
+** Cursors can move when the row they are pointing at is deleted out
+** from under them, for example.  Cursor might also move if a btree
+** is rebalanced.
+**
+** Calling this routine with a NULL cursor pointer returns false.
+**
+** Use the separate sqlite3BtreeCursorRestore() routine to restore a cursor
+** back to where it ought to be if this routine returns true.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor *pCur){
+  assert( EIGHT_BYTE_ALIGNMENT(pCur)
+       || pCur==sqlite3BtreeFakeValidCursor() );
+  assert( offsetof(BtCursor, eState)==0 );
+  assert( sizeof(pCur->eState)==1 );
+  return CURSOR_VALID != *(u8*)pCur;
+}
+
+/*
+** Return a pointer to a fake BtCursor object that will always answer
+** false to the sqlite3BtreeCursorHasMoved() routine above.  The fake
+** cursor returned must not be used with any other Btree interface.
+*/
+SQLITE_PRIVATE BtCursor *sqlite3BtreeFakeValidCursor(void){
+  static u8 fakeCursor = CURSOR_VALID;
+  assert( offsetof(BtCursor, eState)==0 );
+  return (BtCursor*)&fakeCursor;
+}
+
+/*
+** This routine restores a cursor back to its original position after it
+** has been moved by some outside activity (such as a btree rebalance or
+** a row having been deleted out from under the cursor).
+**
+** On success, the *pDifferentRow parameter is false if the cursor is left
+** pointing at exactly the same row.  *pDifferntRow is the row the cursor
+** was pointing to has been deleted, forcing the cursor to point to some
+** nearby row.
+**
+** This routine should only be called for a cursor that just returned
+** TRUE from sqlite3BtreeCursorHasMoved().
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorRestore(BtCursor *pCur, int *pDifferentRow){
+  int rc;
+
+  assert( pCur!=0 );
+  assert( pCur->eState!=CURSOR_VALID );
+  rc = restoreCursorPosition(pCur);
+  if( rc ){
+    *pDifferentRow = 1;
+    return rc;
+  }
+  if( pCur->eState!=CURSOR_VALID ){
+    *pDifferentRow = 1;
+  }else{
+    *pDifferentRow = 0;
+  }
+  return SQLITE_OK;
+}
+
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/*
+** Provide hints to the cursor.  The particular hint given (and the type
+** and number of the varargs parameters) is determined by the eHintType
+** parameter.  See the definitions of the BTREE_HINT_* macros for details.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorHint(BtCursor *pCur, int eHintType, ...){
+  /* Used only by system that substitute their own storage engine */
+#ifdef SQLITE_DEBUG
+  if( ALWAYS(eHintType==BTREE_HINT_RANGE) ){
+    va_list ap;
+    Expr *pExpr;
+    Walker w;
+    memset(&w, 0, sizeof(w));
+    w.xExprCallback = sqlite3CursorRangeHintExprCheck;
+    va_start(ap, eHintType);
+    pExpr = va_arg(ap, Expr*);
+    w.u.aMem = va_arg(ap, Mem*);
+    va_end(ap);
+    assert( pExpr!=0 );
+    assert( w.u.aMem!=0 );
+    sqlite3WalkExpr(&w, pExpr);
+  }
+#endif /* SQLITE_DEBUG */
+}
+#endif /* SQLITE_ENABLE_CURSOR_HINTS */
+
+
+/*
+** Provide flag hints to the cursor.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorHintFlags(BtCursor *pCur, unsigned x){
+  assert( x==BTREE_SEEK_EQ || x==BTREE_BULKLOAD || x==0 );
+  pCur->hints = x;
+}
+
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Given a page number of a regular database page, return the page
+** number for the pointer-map page that contains the entry for the
+** input page number.
+**
+** Return 0 (not a valid page) for pgno==1 since there is
+** no pointer map associated with page 1.  The integrity_check logic
+** requires that ptrmapPageno(*,1)!=1.
+*/
+static Pgno ptrmapPageno(BtShared *pBt, Pgno pgno){
+  int nPagesPerMapPage;
+  Pgno iPtrMap, ret;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pgno<2 ) return 0;
+  nPagesPerMapPage = (pBt->usableSize/5)+1;
+  iPtrMap = (pgno-2)/nPagesPerMapPage;
+  ret = (iPtrMap*nPagesPerMapPage) + 2;
+  if( ret==PENDING_BYTE_PAGE(pBt) ){
+    ret++;
+  }
+  return ret;
+}
+
+/*
+** Write an entry into the pointer map.
+**
+** This routine updates the pointer map entry for page number 'key'
+** so that it maps to type 'eType' and parent page number 'pgno'.
+**
+** If *pRC is initially non-zero (non-SQLITE_OK) then this routine is
+** a no-op.  If an error occurs, the appropriate error code is written
+** into *pRC.
+*/
+static void ptrmapPut(BtShared *pBt, Pgno key, u8 eType, Pgno parent, int *pRC){
+  DbPage *pDbPage;  /* The pointer map page */
+  u8 *pPtrmap;      /* The pointer map data */
+  Pgno iPtrmap;     /* The pointer map page number */
+  int offset;       /* Offset in pointer map page */
+  int rc;           /* Return code from subfunctions */
+
+  if( *pRC ) return;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  /* The super-journal page number must never be used as a pointer map page */
+  assert( 0==PTRMAP_ISPAGE(pBt, PENDING_BYTE_PAGE(pBt)) );
+
+  assert( pBt->autoVacuum );
+  if( key==0 ){
+    *pRC = SQLITE_CORRUPT_BKPT;
+    return;
+  }
+  iPtrmap = PTRMAP_PAGENO(pBt, key);
+  rc = sqlite3PagerGet(pBt->pPager, iPtrmap, &pDbPage, 0);
+  if( rc!=SQLITE_OK ){
+    *pRC = rc;
+    return;
+  }
+  if( ((char*)sqlite3PagerGetExtra(pDbPage))[0]!=0 ){
+    /* The first byte of the extra data is the MemPage.isInit byte.
+    ** If that byte is set, it means this page is also being used
+    ** as a btree page. */
+    *pRC = SQLITE_CORRUPT_BKPT;
+    goto ptrmap_exit;
+  }
+  offset = PTRMAP_PTROFFSET(iPtrmap, key);
+  if( offset<0 ){
+    *pRC = SQLITE_CORRUPT_BKPT;
+    goto ptrmap_exit;
+  }
+  assert( offset <= (int)pBt->usableSize-5 );
+  pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
+
+  if( eType!=pPtrmap[offset] || get4byte(&pPtrmap[offset+1])!=parent ){
+    TRACE(("PTRMAP_UPDATE: %u->(%u,%u)\n", key, eType, parent));
+    *pRC= rc = sqlite3PagerWrite(pDbPage);
+    if( rc==SQLITE_OK ){
+      pPtrmap[offset] = eType;
+      put4byte(&pPtrmap[offset+1], parent);
+    }
+  }
+
+ptrmap_exit:
+  sqlite3PagerUnref(pDbPage);
+}
+
+/*
+** Read an entry from the pointer map.
+**
+** This routine retrieves the pointer map entry for page 'key', writing
+** the type and parent page number to *pEType and *pPgno respectively.
+** An error code is returned if something goes wrong, otherwise SQLITE_OK.
+*/
+static int ptrmapGet(BtShared *pBt, Pgno key, u8 *pEType, Pgno *pPgno){
+  DbPage *pDbPage;   /* The pointer map page */
+  int iPtrmap;       /* Pointer map page index */
+  u8 *pPtrmap;       /* Pointer map page data */
+  int offset;        /* Offset of entry in pointer map */
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+
+  iPtrmap = PTRMAP_PAGENO(pBt, key);
+  rc = sqlite3PagerGet(pBt->pPager, iPtrmap, &pDbPage, 0);
+  if( rc!=0 ){
+    return rc;
+  }
+  pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
+
+  offset = PTRMAP_PTROFFSET(iPtrmap, key);
+  if( offset<0 ){
+    sqlite3PagerUnref(pDbPage);
+    return SQLITE_CORRUPT_BKPT;
+  }
+  assert( offset <= (int)pBt->usableSize-5 );
+  assert( pEType!=0 );
+  *pEType = pPtrmap[offset];
+  if( pPgno ) *pPgno = get4byte(&pPtrmap[offset+1]);
+
+  sqlite3PagerUnref(pDbPage);
+  if( *pEType<1 || *pEType>5 ) return SQLITE_CORRUPT_PGNO(iPtrmap);
+  return SQLITE_OK;
+}
+
+#else /* if defined SQLITE_OMIT_AUTOVACUUM */
+  #define ptrmapPut(w,x,y,z,rc)
+  #define ptrmapGet(w,x,y,z) SQLITE_OK
+  #define ptrmapPutOvflPtr(x, y, z, rc)
+#endif
+
+/*
+** Given a btree page and a cell index (0 means the first cell on
+** the page, 1 means the second cell, and so forth) return a pointer
+** to the cell content.
+**
+** findCellPastPtr() does the same except it skips past the initial
+** 4-byte child pointer found on interior pages, if there is one.
+**
+** This routine works only for pages that do not contain overflow cells.
+*/
+#define findCell(P,I) \
+  ((P)->aData + ((P)->maskPage & get2byteAligned(&(P)->aCellIdx[2*(I)])))
+#define findCellPastPtr(P,I) \
+  ((P)->aDataOfst + ((P)->maskPage & get2byteAligned(&(P)->aCellIdx[2*(I)])))
+
+
+/*
+** This is common tail processing for btreeParseCellPtr() and
+** btreeParseCellPtrIndex() for the case when the cell does not fit entirely
+** on a single B-tree page.  Make necessary adjustments to the CellInfo
+** structure.
+*/
+static SQLITE_NOINLINE void btreeParseCellAdjustSizeForOverflow(
+  MemPage *pPage,         /* Page containing the cell */
+  u8 *pCell,              /* Pointer to the cell text. */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  /* If the payload will not fit completely on the local page, we have
+  ** to decide how much to store locally and how much to spill onto
+  ** overflow pages.  The strategy is to minimize the amount of unused
+  ** space on overflow pages while keeping the amount of local storage
+  ** in between minLocal and maxLocal.
+  **
+  ** Warning:  changing the way overflow payload is distributed in any
+  ** way will result in an incompatible file format.
+  */
+  int minLocal;  /* Minimum amount of payload held locally */
+  int maxLocal;  /* Maximum amount of payload held locally */
+  int surplus;   /* Overflow payload available for local storage */
+
+  minLocal = pPage->minLocal;
+  maxLocal = pPage->maxLocal;
+  surplus = minLocal + (pInfo->nPayload - minLocal)%(pPage->pBt->usableSize-4);
+  testcase( surplus==maxLocal );
+  testcase( surplus==maxLocal+1 );
+  if( surplus <= maxLocal ){
+    pInfo->nLocal = (u16)surplus;
+  }else{
+    pInfo->nLocal = (u16)minLocal;
+  }
+  pInfo->nSize = (u16)(&pInfo->pPayload[pInfo->nLocal] - pCell) + 4;
+}
+
+/*
+** Given a record with nPayload bytes of payload stored within btree
+** page pPage, return the number of bytes of payload stored locally.
+*/
+static int btreePayloadToLocal(MemPage *pPage, i64 nPayload){
+  int maxLocal;  /* Maximum amount of payload held locally */
+  maxLocal = pPage->maxLocal;
+  if( nPayload<=maxLocal ){
+    return nPayload;
+  }else{
+    int minLocal;  /* Minimum amount of payload held locally */
+    int surplus;   /* Overflow payload available for local storage */
+    minLocal = pPage->minLocal;
+    surplus = minLocal + (nPayload - minLocal)%(pPage->pBt->usableSize-4);
+    return ( surplus <= maxLocal ) ? surplus : minLocal;
+  }
+}
+
+/*
+** The following routines are implementations of the MemPage.xParseCell()
+** method.
+**
+** Parse a cell content block and fill in the CellInfo structure.
+**
+** btreeParseCellPtr()        =>   table btree leaf nodes
+** btreeParseCellNoPayload()  =>   table btree internal nodes
+** btreeParseCellPtrIndex()   =>   index btree nodes
+**
+** There is also a wrapper function btreeParseCell() that works for
+** all MemPage types and that references the cell by index rather than
+** by pointer.
+*/
+static void btreeParseCellPtrNoPayload(
+  MemPage *pPage,         /* Page containing the cell */
+  u8 *pCell,              /* Pointer to the cell text. */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->leaf==0 );
+  assert( pPage->childPtrSize==4 );
+#ifndef SQLITE_DEBUG
+  UNUSED_PARAMETER(pPage);
+#endif
+  pInfo->nSize = 4 + getVarint(&pCell[4], (u64*)&pInfo->nKey);
+  pInfo->nPayload = 0;
+  pInfo->nLocal = 0;
+  pInfo->pPayload = 0;
+  return;
+}
+static void btreeParseCellPtr(
+  MemPage *pPage,         /* Page containing the cell */
+  u8 *pCell,              /* Pointer to the cell text. */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  u8 *pIter;              /* For scanning through pCell */
+  u32 nPayload;           /* Number of bytes of cell payload */
+  u64 iKey;               /* Extracted Key value */
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->leaf==0 || pPage->leaf==1 );
+  assert( pPage->intKeyLeaf );
+  assert( pPage->childPtrSize==0 );
+  pIter = pCell;
+
+  /* The next block of code is equivalent to:
+  **
+  **     pIter += getVarint32(pIter, nPayload);
+  **
+  ** The code is inlined to avoid a function call.
+  */
+  nPayload = *pIter;
+  if( nPayload>=0x80 ){
+    u8 *pEnd = &pIter[8];
+    nPayload &= 0x7f;
+    do{
+      nPayload = (nPayload<<7) | (*++pIter & 0x7f);
+    }while( (*pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+
+  /* The next block of code is equivalent to:
+  **
+  **     pIter += getVarint(pIter, (u64*)&pInfo->nKey);
+  **
+  ** The code is inlined and the loop is unrolled for performance.
+  ** This routine is a high-runner.
+  */
+  iKey = *pIter;
+  if( iKey>=0x80 ){
+    u8 x;
+    iKey = (iKey<<7) ^ (x = *++pIter);
+    if( x>=0x80 ){
+      iKey = (iKey<<7) ^ (x = *++pIter);
+      if( x>=0x80 ){
+        iKey = (iKey<<7) ^ 0x10204000 ^ (x = *++pIter);
+        if( x>=0x80 ){
+          iKey = (iKey<<7) ^ 0x4000 ^ (x = *++pIter);
+          if( x>=0x80 ){
+            iKey = (iKey<<7) ^ 0x4000 ^ (x = *++pIter);
+            if( x>=0x80 ){
+              iKey = (iKey<<7) ^ 0x4000 ^ (x = *++pIter);
+              if( x>=0x80 ){
+                iKey = (iKey<<7) ^ 0x4000 ^ (x = *++pIter);
+                if( x>=0x80 ){
+                  iKey = (iKey<<8) ^ 0x8000 ^ (*++pIter);
+                }
+              }
+            }
+          }
+        }
+      }else{
+        iKey ^= 0x204000;
+      }
+    }else{
+      iKey ^= 0x4000;
+    }
+  }
+  pIter++;
+
+  pInfo->nKey = *(i64*)&iKey;
+  pInfo->nPayload = nPayload;
+  pInfo->pPayload = pIter;
+  testcase( nPayload==pPage->maxLocal );
+  testcase( nPayload==(u32)pPage->maxLocal+1 );
+  if( nPayload<=pPage->maxLocal ){
+    /* This is the (easy) common case where the entire payload fits
+    ** on the local page.  No overflow is required.
+    */
+    pInfo->nSize = nPayload + (u16)(pIter - pCell);
+    if( pInfo->nSize<4 ) pInfo->nSize = 4;
+    pInfo->nLocal = (u16)nPayload;
+  }else{
+    btreeParseCellAdjustSizeForOverflow(pPage, pCell, pInfo);
+  }
+}
+static void btreeParseCellPtrIndex(
+  MemPage *pPage,         /* Page containing the cell */
+  u8 *pCell,              /* Pointer to the cell text. */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  u8 *pIter;              /* For scanning through pCell */
+  u32 nPayload;           /* Number of bytes of cell payload */
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->leaf==0 || pPage->leaf==1 );
+  assert( pPage->intKeyLeaf==0 );
+  pIter = pCell + pPage->childPtrSize;
+  nPayload = *pIter;
+  if( nPayload>=0x80 ){
+    u8 *pEnd = &pIter[8];
+    nPayload &= 0x7f;
+    do{
+      nPayload = (nPayload<<7) | (*++pIter & 0x7f);
+    }while( *(pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+  pInfo->nKey = nPayload;
+  pInfo->nPayload = nPayload;
+  pInfo->pPayload = pIter;
+  testcase( nPayload==pPage->maxLocal );
+  testcase( nPayload==(u32)pPage->maxLocal+1 );
+  if( nPayload<=pPage->maxLocal ){
+    /* This is the (easy) common case where the entire payload fits
+    ** on the local page.  No overflow is required.
+    */
+    pInfo->nSize = nPayload + (u16)(pIter - pCell);
+    if( pInfo->nSize<4 ) pInfo->nSize = 4;
+    pInfo->nLocal = (u16)nPayload;
+  }else{
+    btreeParseCellAdjustSizeForOverflow(pPage, pCell, pInfo);
+  }
+}
+static void btreeParseCell(
+  MemPage *pPage,         /* Page containing the cell */
+  int iCell,              /* The cell index.  First cell is 0 */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  pPage->xParseCell(pPage, findCell(pPage, iCell), pInfo);
+}
+
+/*
+** The following routines are implementations of the MemPage.xCellSize
+** method.
+**
+** Compute the total number of bytes that a Cell needs in the cell
+** data area of the btree-page.  The return number includes the cell
+** data header and the local payload, but not any overflow page or
+** the space used by the cell pointer.
+**
+** cellSizePtrNoPayload()    =>   table internal nodes
+** cellSizePtrTableLeaf()    =>   table leaf nodes
+** cellSizePtr()             =>   index internal nodes
+** cellSizeIdxLeaf()         =>   index leaf nodes
+*/
+static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell + 4;                   /* For looping over bytes of pCell */
+  u8 *pEnd;                                /* End mark for a varint */
+  u32 nSize;                               /* Size value to return */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  pPage->xParseCell(pPage, pCell, &debuginfo);
+#endif
+
+  assert( pPage->childPtrSize==4 );
+  nSize = *pIter;
+  if( nSize>=0x80 ){
+    pEnd = &pIter[8];
+    nSize &= 0x7f;
+    do{
+      nSize = (nSize<<7) | (*++pIter & 0x7f);
+    }while( *(pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+  testcase( nSize==pPage->maxLocal );
+  testcase( nSize==(u32)pPage->maxLocal+1 );
+  if( nSize<=pPage->maxLocal ){
+    nSize += (u32)(pIter - pCell);
+    assert( nSize>4 );
+  }else{
+    int minLocal = pPage->minLocal;
+    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
+    testcase( nSize==pPage->maxLocal );
+    testcase( nSize==(u32)pPage->maxLocal+1 );
+    if( nSize>pPage->maxLocal ){
+      nSize = minLocal;
+    }
+    nSize += 4 + (u16)(pIter - pCell);
+  }
+  assert( nSize==debuginfo.nSize || CORRUPT_DB );
+  return (u16)nSize;
+}
+static u16 cellSizePtrIdxLeaf(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell;                       /* For looping over bytes of pCell */
+  u8 *pEnd;                                /* End mark for a varint */
+  u32 nSize;                               /* Size value to return */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  pPage->xParseCell(pPage, pCell, &debuginfo);
+#endif
+
+  assert( pPage->childPtrSize==0 );
+  nSize = *pIter;
+  if( nSize>=0x80 ){
+    pEnd = &pIter[8];
+    nSize &= 0x7f;
+    do{
+      nSize = (nSize<<7) | (*++pIter & 0x7f);
+    }while( *(pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+  testcase( nSize==pPage->maxLocal );
+  testcase( nSize==(u32)pPage->maxLocal+1 );
+  if( nSize<=pPage->maxLocal ){
+    nSize += (u32)(pIter - pCell);
+    if( nSize<4 ) nSize = 4;
+  }else{
+    int minLocal = pPage->minLocal;
+    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
+    testcase( nSize==pPage->maxLocal );
+    testcase( nSize==(u32)pPage->maxLocal+1 );
+    if( nSize>pPage->maxLocal ){
+      nSize = minLocal;
+    }
+    nSize += 4 + (u16)(pIter - pCell);
+  }
+  assert( nSize==debuginfo.nSize || CORRUPT_DB );
+  return (u16)nSize;
+}
+static u16 cellSizePtrNoPayload(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell + 4; /* For looping over bytes of pCell */
+  u8 *pEnd;              /* End mark for a varint */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  pPage->xParseCell(pPage, pCell, &debuginfo);
+#else
+  UNUSED_PARAMETER(pPage);
+#endif
+
+  assert( pPage->childPtrSize==4 );
+  pEnd = pIter + 9;
+  while( (*pIter++)&0x80 && pIter<pEnd );
+  assert( debuginfo.nSize==(u16)(pIter - pCell) || CORRUPT_DB );
+  return (u16)(pIter - pCell);
+}
+static u16 cellSizePtrTableLeaf(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell;   /* For looping over bytes of pCell */
+  u8 *pEnd;            /* End mark for a varint */
+  u32 nSize;           /* Size value to return */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  pPage->xParseCell(pPage, pCell, &debuginfo);
+#endif
+
+  nSize = *pIter;
+  if( nSize>=0x80 ){
+    pEnd = &pIter[8];
+    nSize &= 0x7f;
+    do{
+      nSize = (nSize<<7) | (*++pIter & 0x7f);
+    }while( *(pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+  /* pIter now points at the 64-bit integer key value, a variable length
+  ** integer. The following block moves pIter to point at the first byte
+  ** past the end of the key value. */
+  if( (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80 ){ pIter++; }
+  testcase( nSize==pPage->maxLocal );
+  testcase( nSize==(u32)pPage->maxLocal+1 );
+  if( nSize<=pPage->maxLocal ){
+    nSize += (u32)(pIter - pCell);
+    if( nSize<4 ) nSize = 4;
+  }else{
+    int minLocal = pPage->minLocal;
+    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
+    testcase( nSize==pPage->maxLocal );
+    testcase( nSize==(u32)pPage->maxLocal+1 );
+    if( nSize>pPage->maxLocal ){
+      nSize = minLocal;
+    }
+    nSize += 4 + (u16)(pIter - pCell);
+  }
+  assert( nSize==debuginfo.nSize || CORRUPT_DB );
+  return (u16)nSize;
+}
+
+
+#ifdef SQLITE_DEBUG
+/* This variation on cellSizePtr() is used inside of assert() statements
+** only. */
+static u16 cellSize(MemPage *pPage, int iCell){
+  return pPage->xCellSize(pPage, findCell(pPage, iCell));
+}
+#endif
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** The cell pCell is currently part of page pSrc but will ultimately be part
+** of pPage.  (pSrc and pPage are often the same.)  If pCell contains a
+** pointer to an overflow page, insert an entry into the pointer-map for
+** the overflow page that will be valid after pCell has been moved to pPage.
+*/
+static void ptrmapPutOvflPtr(MemPage *pPage, MemPage *pSrc, u8 *pCell,int *pRC){
+  CellInfo info;
+  if( *pRC ) return;
+  assert( pCell!=0 );
+  pPage->xParseCell(pPage, pCell, &info);
+  if( info.nLocal<info.nPayload ){
+    Pgno ovfl;
+    if( SQLITE_OVERFLOW(pSrc->aDataEnd, pCell, pCell+info.nLocal) ){
+      testcase( pSrc!=pPage );
+      *pRC = SQLITE_CORRUPT_BKPT;
+      return;
+    }
+    ovfl = get4byte(&pCell[info.nSize-4]);
+    ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
+  }
+}
+#endif
+
+
+/*
+** Defragment the page given. This routine reorganizes cells within the
+** page so that there are no free-blocks on the free-block list.
+**
+** Parameter nMaxFrag is the maximum amount of fragmented space that may be
+** present in the page after this routine returns.
+**
+** EVIDENCE-OF: R-44582-60138 SQLite may from time to time reorganize a
+** b-tree page so that there are no freeblocks or fragment bytes, all
+** unused bytes are contained in the unallocated space region, and all
+** cells are packed tightly at the end of the page.
+*/
+static int defragmentPage(MemPage *pPage, int nMaxFrag){
+  int i;                     /* Loop counter */
+  int pc;                    /* Address of the i-th cell */
+  int hdr;                   /* Offset to the page header */
+  int size;                  /* Size of a cell */
+  int usableSize;            /* Number of usable bytes on a page */
+  int cellOffset;            /* Offset to the cell pointer array */
+  int cbrk;                  /* Offset to the cell content area */
+  int nCell;                 /* Number of cells on the page */
+  unsigned char *data;       /* The page data */
+  unsigned char *temp;       /* Temp area for cell content */
+  unsigned char *src;        /* Source of content */
+  int iCellFirst;            /* First allowable cell index */
+  int iCellLast;             /* Last possible cell index */
+  int iCellStart;            /* First cell offset in input */
+
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( pPage->pBt!=0 );
+  assert( pPage->pBt->usableSize <= SQLITE_MAX_PAGE_SIZE );
+  assert( pPage->nOverflow==0 );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  data = pPage->aData;
+  hdr = pPage->hdrOffset;
+  cellOffset = pPage->cellOffset;
+  nCell = pPage->nCell;
+  assert( nCell==get2byte(&data[hdr+3]) || CORRUPT_DB );
+  iCellFirst = cellOffset + 2*nCell;
+  usableSize = pPage->pBt->usableSize;
+
+  /* This block handles pages with two or fewer free blocks and nMaxFrag
+  ** or fewer fragmented bytes. In this case it is faster to move the
+  ** two (or one) blocks of cells using memmove() and add the required
+  ** offsets to each pointer in the cell-pointer array than it is to
+  ** reconstruct the entire page.  */
+  if( (int)data[hdr+7]<=nMaxFrag ){
+    int iFree = get2byte(&data[hdr+1]);
+    if( iFree>usableSize-4 ) return SQLITE_CORRUPT_PAGE(pPage);
+    if( iFree ){
+      int iFree2 = get2byte(&data[iFree]);
+      if( iFree2>usableSize-4 ) return SQLITE_CORRUPT_PAGE(pPage);
+      if( 0==iFree2 || (data[iFree2]==0 && data[iFree2+1]==0) ){
+        u8 *pEnd = &data[cellOffset + nCell*2];
+        u8 *pAddr;
+        int sz2 = 0;
+        int sz = get2byte(&data[iFree+2]);
+        int top = get2byte(&data[hdr+5]);
+        if( top>=iFree ){
+          return SQLITE_CORRUPT_PAGE(pPage);
+        }
+        if( iFree2 ){
+          if( iFree+sz>iFree2 ) return SQLITE_CORRUPT_PAGE(pPage);
+          sz2 = get2byte(&data[iFree2+2]);
+          if( iFree2+sz2 > usableSize ) return SQLITE_CORRUPT_PAGE(pPage);
+          memmove(&data[iFree+sz+sz2], &data[iFree+sz], iFree2-(iFree+sz));
+          sz += sz2;
+        }else if( iFree+sz>usableSize ){
+          return SQLITE_CORRUPT_PAGE(pPage);
+        }
+
+        cbrk = top+sz;
+        assert( cbrk+(iFree-top) <= usableSize );
+        memmove(&data[cbrk], &data[top], iFree-top);
+        for(pAddr=&data[cellOffset]; pAddr<pEnd; pAddr+=2){
+          pc = get2byte(pAddr);
+          if( pc<iFree ){ put2byte(pAddr, pc+sz); }
+          else if( pc<iFree2 ){ put2byte(pAddr, pc+sz2); }
+        }
+        goto defragment_out;
+      }
+    }
+  }
+
+  cbrk = usableSize;
+  iCellLast = usableSize - 4;
+  iCellStart = get2byte(&data[hdr+5]);
+  if( nCell>0 ){
+    temp = sqlite3PagerTempSpace(pPage->pBt->pPager);
+    memcpy(temp, data, usableSize);
+    src = temp;
+    for(i=0; i<nCell; i++){
+      u8 *pAddr;     /* The i-th cell pointer */
+      pAddr = &data[cellOffset + i*2];
+      pc = get2byte(pAddr);
+      testcase( pc==iCellFirst );
+      testcase( pc==iCellLast );
+      /* These conditions have already been verified in btreeInitPage()
+      ** if PRAGMA cell_size_check=ON.
+      */
+      if( pc>iCellLast ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      assert( pc>=0 && pc<=iCellLast );
+      size = pPage->xCellSize(pPage, &src[pc]);
+      cbrk -= size;
+      if( cbrk<iCellStart || pc+size>usableSize ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      assert( cbrk+size<=usableSize && cbrk>=iCellStart );
+      testcase( cbrk+size==usableSize );
+      testcase( pc+size==usableSize );
+      put2byte(pAddr, cbrk);
+      memcpy(&data[cbrk], &src[pc], size);
+    }
+  }
+  data[hdr+7] = 0;
+
+defragment_out:
+  assert( pPage->nFree>=0 );
+  if( data[hdr+7]+cbrk-iCellFirst!=pPage->nFree ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  assert( cbrk>=iCellFirst );
+  put2byte(&data[hdr+5], cbrk);
+  data[hdr+1] = 0;
+  data[hdr+2] = 0;
+  memset(&data[iCellFirst], 0, cbrk-iCellFirst);
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  return SQLITE_OK;
+}
+
+/*
+** Search the free-list on page pPg for space to store a cell nByte bytes in
+** size. If one can be found, return a pointer to the space and remove it
+** from the free-list.
+**
+** If no suitable space can be found on the free-list, return NULL.
+**
+** This function may detect corruption within pPg.  If corruption is
+** detected then *pRc is set to SQLITE_CORRUPT and NULL is returned.
+**
+** Slots on the free list that are between 1 and 3 bytes larger than nByte
+** will be ignored if adding the extra space to the fragmentation count
+** causes the fragmentation count to exceed 60.
+*/
+static u8 *pageFindSlot(MemPage *pPg, int nByte, int *pRc){
+  const int hdr = pPg->hdrOffset;            /* Offset to page header */
+  u8 * const aData = pPg->aData;             /* Page data */
+  int iAddr = hdr + 1;                       /* Address of ptr to pc */
+  u8 *pTmp = &aData[iAddr];                  /* Temporary ptr into aData[] */
+  int pc = get2byte(pTmp);                   /* Address of a free slot */
+  int x;                                     /* Excess size of the slot */
+  int maxPC = pPg->pBt->usableSize - nByte;  /* Max address for a usable slot */
+  int size;                                  /* Size of the free slot */
+
+  assert( pc>0 );
+  while( pc<=maxPC ){
+    /* EVIDENCE-OF: R-22710-53328 The third and fourth bytes of each
+    ** freeblock form a big-endian integer which is the size of the freeblock
+    ** in bytes, including the 4-byte header. */
+    pTmp = &aData[pc+2];
+    size = get2byte(pTmp);
+    if( (x = size - nByte)>=0 ){
+      testcase( x==4 );
+      testcase( x==3 );
+      if( x<4 ){
+        /* EVIDENCE-OF: R-11498-58022 In a well-formed b-tree page, the total
+        ** number of bytes in fragments may not exceed 60. */
+        if( aData[hdr+7]>57 ) return 0;
+
+        /* Remove the slot from the free-list. Update the number of
+        ** fragmented bytes within the page. */
+        memcpy(&aData[iAddr], &aData[pc], 2);
+        aData[hdr+7] += (u8)x;
+        return &aData[pc];
+      }else if( x+pc > maxPC ){
+        /* This slot extends off the end of the usable part of the page */
+        *pRc = SQLITE_CORRUPT_PAGE(pPg);
+        return 0;
+      }else{
+        /* The slot remains on the free-list. Reduce its size to account
+        ** for the portion used by the new allocation. */
+        put2byte(&aData[pc+2], x);
+      }
+      return &aData[pc + x];
+    }
+    iAddr = pc;
+    pTmp = &aData[pc];
+    pc = get2byte(pTmp);
+    if( pc<=iAddr ){
+      if( pc ){
+        /* The next slot in the chain comes before the current slot */
+        *pRc = SQLITE_CORRUPT_PAGE(pPg);
+      }
+      return 0;
+    }
+  }
+  if( pc>maxPC+nByte-4 ){
+    /* The free slot chain extends off the end of the page */
+    *pRc = SQLITE_CORRUPT_PAGE(pPg);
+  }
+  return 0;
+}
+
+/*
+** Allocate nByte bytes of space from within the B-Tree page passed
+** as the first argument. Write into *pIdx the index into pPage->aData[]
+** of the first byte of allocated space. Return either SQLITE_OK or
+** an error code (usually SQLITE_CORRUPT).
+**
+** The caller guarantees that there is sufficient space to make the
+** allocation.  This routine might need to defragment in order to bring
+** all the space together, however.  This routine will avoid using
+** the first two bytes past the cell pointer area since presumably this
+** allocation is being made in order to insert a new cell, so we will
+** also end up needing a new cell pointer.
+*/
+static SQLITE_INLINE int allocateSpace(MemPage *pPage, int nByte, int *pIdx){
+  const int hdr = pPage->hdrOffset;    /* Local cache of pPage->hdrOffset */
+  u8 * const data = pPage->aData;      /* Local cache of pPage->aData */
+  int top;                             /* First byte of cell content area */
+  int rc = SQLITE_OK;                  /* Integer return code */
+  u8 *pTmp;                            /* Temp ptr into data[] */
+  int gap;        /* First byte of gap between cell pointers and cell content */
+
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( pPage->pBt );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( nByte>=0 );  /* Minimum cell size is 4 */
+  assert( pPage->nFree>=nByte );
+  assert( pPage->nOverflow==0 );
+  assert( nByte < (int)(pPage->pBt->usableSize-8) );
+
+  assert( pPage->cellOffset == hdr + 12 - 4*pPage->leaf );
+  gap = pPage->cellOffset + 2*pPage->nCell;
+  assert( gap<=65536 );
+  /* EVIDENCE-OF: R-29356-02391 If the database uses a 65536-byte page size
+  ** and the reserved space is zero (the usual value for reserved space)
+  ** then the cell content offset of an empty page wants to be 65536.
+  ** However, that integer is too large to be stored in a 2-byte unsigned
+  ** integer, so a value of 0 is used in its place. */
+  pTmp = &data[hdr+5];
+  top = get2byte(pTmp);
+  if( gap>top ){
+    if( top==0 && pPage->pBt->usableSize==65536 ){
+      top = 65536;
+    }else{
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }else if( top>(int)pPage->pBt->usableSize ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+
+  /* If there is enough space between gap and top for one more cell pointer,
+  ** and if the freelist is not empty, then search the
+  ** freelist looking for a slot big enough to satisfy the request.
+  */
+  testcase( gap+2==top );
+  testcase( gap+1==top );
+  testcase( gap==top );
+  if( (data[hdr+2] || data[hdr+1]) && gap+2<=top ){
+    u8 *pSpace = pageFindSlot(pPage, nByte, &rc);
+    if( pSpace ){
+      int g2;
+      assert( pSpace+nByte<=data+pPage->pBt->usableSize );
+      *pIdx = g2 = (int)(pSpace-data);
+      if( g2<=gap ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }else{
+        return SQLITE_OK;
+      }
+    }else if( rc ){
+      return rc;
+    }
+  }
+
+  /* The request could not be fulfilled using a freelist slot.  Check
+  ** to see if defragmentation is necessary.
+  */
+  testcase( gap+2+nByte==top );
+  if( gap+2+nByte>top ){
+    assert( pPage->nCell>0 || CORRUPT_DB );
+    assert( pPage->nFree>=0 );
+    rc = defragmentPage(pPage, MIN(4, pPage->nFree - (2+nByte)));
+    if( rc ) return rc;
+    top = get2byteNotZero(&data[hdr+5]);
+    assert( gap+2+nByte<=top );
+  }
+
+
+  /* Allocate memory from the gap in between the cell pointer array
+  ** and the cell content area.  The btreeComputeFreeSpace() call has already
+  ** validated the freelist.  Given that the freelist is valid, there
+  ** is no way that the allocation can extend off the end of the page.
+  ** The assert() below verifies the previous sentence.
+  */
+  top -= nByte;
+  put2byte(&data[hdr+5], top);
+  assert( top+nByte <= (int)pPage->pBt->usableSize );
+  *pIdx = top;
+  return SQLITE_OK;
+}
+
+/*
+** Return a section of the pPage->aData to the freelist.
+** The first byte of the new free block is pPage->aData[iStart]
+** and the size of the block is iSize bytes.
+**
+** Adjacent freeblocks are coalesced.
+**
+** Even though the freeblock list was checked by btreeComputeFreeSpace(),
+** that routine will not detect overlap between cells or freeblocks.  Nor
+** does it detect cells or freeblocks that encroach into the reserved bytes
+** at the end of the page.  So do additional corruption checks inside this
+** routine and return SQLITE_CORRUPT if any problems are found.
+*/
+static int freeSpace(MemPage *pPage, u16 iStart, u16 iSize){
+  u16 iPtr;                             /* Address of ptr to next freeblock */
+  u16 iFreeBlk;                         /* Address of the next freeblock */
+  u8 hdr;                               /* Page header size.  0 or 100 */
+  u8 nFrag = 0;                         /* Reduction in fragmentation */
+  u16 iOrigSize = iSize;                /* Original value of iSize */
+  u16 x;                                /* Offset to cell content area */
+  u32 iEnd = iStart + iSize;            /* First byte past the iStart buffer */
+  unsigned char *data = pPage->aData;   /* Page content */
+  u8 *pTmp;                             /* Temporary ptr into data[] */
+
+  assert( pPage->pBt!=0 );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( CORRUPT_DB || iStart>=pPage->hdrOffset+6+pPage->childPtrSize );
+  assert( CORRUPT_DB || iEnd <= pPage->pBt->usableSize );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( iSize>=4 );   /* Minimum cell size is 4 */
+  assert( CORRUPT_DB || iStart<=pPage->pBt->usableSize-4 );
+
+  /* The list of freeblocks must be in ascending order.  Find the
+  ** spot on the list where iStart should be inserted.
+  */
+  hdr = pPage->hdrOffset;
+  iPtr = hdr + 1;
+  if( data[iPtr+1]==0 && data[iPtr]==0 ){
+    iFreeBlk = 0;  /* Shortcut for the case when the freelist is empty */
+  }else{
+    while( (iFreeBlk = get2byte(&data[iPtr]))<iStart ){
+      if( iFreeBlk<=iPtr ){
+        if( iFreeBlk==0 ) break; /* TH3: corrupt082.100 */
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      iPtr = iFreeBlk;
+    }
+    if( iFreeBlk>pPage->pBt->usableSize-4 ){ /* TH3: corrupt081.100 */
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    assert( iFreeBlk>iPtr || iFreeBlk==0 || CORRUPT_DB );
+
+    /* At this point:
+    **    iFreeBlk:   First freeblock after iStart, or zero if none
+    **    iPtr:       The address of a pointer to iFreeBlk
+    **
+    ** Check to see if iFreeBlk should be coalesced onto the end of iStart.
+    */
+    if( iFreeBlk && iEnd+3>=iFreeBlk ){
+      nFrag = iFreeBlk - iEnd;
+      if( iEnd>iFreeBlk ) return SQLITE_CORRUPT_PAGE(pPage);
+      iEnd = iFreeBlk + get2byte(&data[iFreeBlk+2]);
+      if( iEnd > pPage->pBt->usableSize ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      iSize = iEnd - iStart;
+      iFreeBlk = get2byte(&data[iFreeBlk]);
+    }
+
+    /* If iPtr is another freeblock (that is, if iPtr is not the freelist
+    ** pointer in the page header) then check to see if iStart should be
+    ** coalesced onto the end of iPtr.
+    */
+    if( iPtr>hdr+1 ){
+      int iPtrEnd = iPtr + get2byte(&data[iPtr+2]);
+      if( iPtrEnd+3>=iStart ){
+        if( iPtrEnd>iStart ) return SQLITE_CORRUPT_PAGE(pPage);
+        nFrag += iStart - iPtrEnd;
+        iSize = iEnd - iPtr;
+        iStart = iPtr;
+      }
+    }
+    if( nFrag>data[hdr+7] ) return SQLITE_CORRUPT_PAGE(pPage);
+    data[hdr+7] -= nFrag;
+  }
+  pTmp = &data[hdr+5];
+  x = get2byte(pTmp);
+  if( pPage->pBt->btsFlags & BTS_FAST_SECURE ){
+    /* Overwrite deleted information with zeros when the secure_delete
+    ** option is enabled */
+    memset(&data[iStart], 0, iSize);
+  }
+  if( iStart<=x ){
+    /* The new freeblock is at the beginning of the cell content area,
+    ** so just extend the cell content area rather than create another
+    ** freelist entry */
+    if( iStart<x ) return SQLITE_CORRUPT_PAGE(pPage);
+    if( iPtr!=hdr+1 ) return SQLITE_CORRUPT_PAGE(pPage);
+    put2byte(&data[hdr+1], iFreeBlk);
+    put2byte(&data[hdr+5], iEnd);
+  }else{
+    /* Insert the new freeblock into the freelist */
+    put2byte(&data[iPtr], iStart);
+    put2byte(&data[iStart], iFreeBlk);
+    put2byte(&data[iStart+2], iSize);
+  }
+  pPage->nFree += iOrigSize;
+  return SQLITE_OK;
+}
+
+/*
+** Decode the flags byte (the first byte of the header) for a page
+** and initialize fields of the MemPage structure accordingly.
+**
+** Only the following combinations are supported.  Anything different
+** indicates a corrupt database files:
+**
+**         PTF_ZERODATA                             (0x02,  2)
+**         PTF_LEAFDATA | PTF_INTKEY                (0x05,  5)
+**         PTF_ZERODATA | PTF_LEAF                  (0x0a, 10)
+**         PTF_LEAFDATA | PTF_INTKEY | PTF_LEAF     (0x0d, 13)
+*/
+static int decodeFlags(MemPage *pPage, int flagByte){
+  BtShared *pBt;     /* A copy of pPage->pBt */
+
+  assert( pPage->hdrOffset==(pPage->pgno==1 ? 100 : 0) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  pBt = pPage->pBt;
+  pPage->max1bytePayload = pBt->max1bytePayload;
+  if( flagByte>=(PTF_ZERODATA | PTF_LEAF) ){
+    pPage->childPtrSize = 0;
+    pPage->leaf = 1;
+    if( flagByte==(PTF_LEAFDATA | PTF_INTKEY | PTF_LEAF) ){
+      pPage->intKeyLeaf = 1;
+      pPage->xCellSize = cellSizePtrTableLeaf;
+      pPage->xParseCell = btreeParseCellPtr;
+      pPage->intKey = 1;
+      pPage->maxLocal = pBt->maxLeaf;
+      pPage->minLocal = pBt->minLeaf;
+    }else if( flagByte==(PTF_ZERODATA | PTF_LEAF) ){
+      pPage->intKey = 0;
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtrIdxLeaf;
+      pPage->xParseCell = btreeParseCellPtrIndex;
+      pPage->maxLocal = pBt->maxLocal;
+      pPage->minLocal = pBt->minLocal;
+    }else{
+      pPage->intKey = 0;
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtrIdxLeaf;
+      pPage->xParseCell = btreeParseCellPtrIndex;
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }else{
+    pPage->childPtrSize = 4;
+    pPage->leaf = 0;
+    if( flagByte==(PTF_ZERODATA) ){
+      pPage->intKey = 0;
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtr;
+      pPage->xParseCell = btreeParseCellPtrIndex;
+      pPage->maxLocal = pBt->maxLocal;
+      pPage->minLocal = pBt->minLocal;
+    }else if( flagByte==(PTF_LEAFDATA | PTF_INTKEY) ){
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtrNoPayload;
+      pPage->xParseCell = btreeParseCellPtrNoPayload;
+      pPage->intKey = 1;
+      pPage->maxLocal = pBt->maxLeaf;
+      pPage->minLocal = pBt->minLeaf;
+    }else{
+      pPage->intKey = 0;
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtr;
+      pPage->xParseCell = btreeParseCellPtrIndex;
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Compute the amount of freespace on the page.  In other words, fill
+** in the pPage->nFree field.
+*/
+static int btreeComputeFreeSpace(MemPage *pPage){
+  int pc;            /* Address of a freeblock within pPage->aData[] */
+  u8 hdr;            /* Offset to beginning of page header */
+  u8 *data;          /* Equal to pPage->aData */
+  int usableSize;    /* Amount of usable space on each page */
+  int nFree;         /* Number of unused bytes on the page */
+  int top;           /* First byte of the cell content area */
+  int iCellFirst;    /* First allowable cell or freeblock offset */
+  int iCellLast;     /* Last possible cell or freeblock offset */
+
+  assert( pPage->pBt!=0 );
+  assert( pPage->pBt->db!=0 );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->pgno==sqlite3PagerPagenumber(pPage->pDbPage) );
+  assert( pPage == sqlite3PagerGetExtra(pPage->pDbPage) );
+  assert( pPage->aData == sqlite3PagerGetData(pPage->pDbPage) );
+  assert( pPage->isInit==1 );
+  assert( pPage->nFree<0 );
+
+  usableSize = pPage->pBt->usableSize;
+  hdr = pPage->hdrOffset;
+  data = pPage->aData;
+  /* EVIDENCE-OF: R-58015-48175 The two-byte integer at offset 5 designates
+  ** the start of the cell content area. A zero value for this integer is
+  ** interpreted as 65536. */
+  top = get2byteNotZero(&data[hdr+5]);
+  iCellFirst = hdr + 8 + pPage->childPtrSize + 2*pPage->nCell;
+  iCellLast = usableSize - 4;
+
+  /* Compute the total free space on the page
+  ** EVIDENCE-OF: R-23588-34450 The two-byte integer at offset 1 gives the
+  ** start of the first freeblock on the page, or is zero if there are no
+  ** freeblocks. */
+  pc = get2byte(&data[hdr+1]);
+  nFree = data[hdr+7] + top;  /* Init nFree to non-freeblock free space */
+  if( pc>0 ){
+    u32 next, size;
+    if( pc<top ){
+      /* EVIDENCE-OF: R-55530-52930 In a well-formed b-tree page, there will
+      ** always be at least one cell before the first freeblock.
+      */
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    while( 1 ){
+      if( pc>iCellLast ){
+        /* Freeblock off the end of the page */
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      next = get2byte(&data[pc]);
+      size = get2byte(&data[pc+2]);
+      nFree = nFree + size;
+      if( next<=pc+size+3 ) break;
+      pc = next;
+    }
+    if( next>0 ){
+      /* Freeblock not in ascending order */
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    if( pc+size>(unsigned int)usableSize ){
+      /* Last freeblock extends past page end */
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }
+
+  /* At this point, nFree contains the sum of the offset to the start
+  ** of the cell-content area plus the number of free bytes within
+  ** the cell-content area. If this is greater than the usable-size
+  ** of the page, then the page must be corrupted. This check also
+  ** serves to verify that the offset to the start of the cell-content
+  ** area, according to the page header, lies within the page.
+  */
+  if( nFree>usableSize || nFree<iCellFirst ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  pPage->nFree = (u16)(nFree - iCellFirst);
+  return SQLITE_OK;
+}
+
+/*
+** Do additional sanity check after btreeInitPage() if
+** PRAGMA cell_size_check=ON
+*/
+static SQLITE_NOINLINE int btreeCellSizeCheck(MemPage *pPage){
+  int iCellFirst;    /* First allowable cell or freeblock offset */
+  int iCellLast;     /* Last possible cell or freeblock offset */
+  int i;             /* Index into the cell pointer array */
+  int sz;            /* Size of a cell */
+  int pc;            /* Address of a freeblock within pPage->aData[] */
+  u8 *data;          /* Equal to pPage->aData */
+  int usableSize;    /* Maximum usable space on the page */
+  int cellOffset;    /* Start of cell content area */
+
+  iCellFirst = pPage->cellOffset + 2*pPage->nCell;
+  usableSize = pPage->pBt->usableSize;
+  iCellLast = usableSize - 4;
+  data = pPage->aData;
+  cellOffset = pPage->cellOffset;
+  if( !pPage->leaf ) iCellLast--;
+  for(i=0; i<pPage->nCell; i++){
+    pc = get2byteAligned(&data[cellOffset+i*2]);
+    testcase( pc==iCellFirst );
+    testcase( pc==iCellLast );
+    if( pc<iCellFirst || pc>iCellLast ){
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    sz = pPage->xCellSize(pPage, &data[pc]);
+    testcase( pc+sz==usableSize );
+    if( pc+sz>usableSize ){
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Initialize the auxiliary information for a disk block.
+**
+** Return SQLITE_OK on success.  If we see that the page does
+** not contain a well-formed database page, then return
+** SQLITE_CORRUPT.  Note that a return of SQLITE_OK does not
+** guarantee that the page is well-formed.  It only shows that
+** we failed to detect any corruption.
+*/
+static int btreeInitPage(MemPage *pPage){
+  u8 *data;          /* Equal to pPage->aData */
+  BtShared *pBt;        /* The main btree structure */
+
+  assert( pPage->pBt!=0 );
+  assert( pPage->pBt->db!=0 );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->pgno==sqlite3PagerPagenumber(pPage->pDbPage) );
+  assert( pPage == sqlite3PagerGetExtra(pPage->pDbPage) );
+  assert( pPage->aData == sqlite3PagerGetData(pPage->pDbPage) );
+  assert( pPage->isInit==0 );
+
+  pBt = pPage->pBt;
+  data = pPage->aData + pPage->hdrOffset;
+  /* EVIDENCE-OF: R-28594-02890 The one-byte flag at offset 0 indicating
+  ** the b-tree page type. */
+  if( decodeFlags(pPage, data[0]) ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
+  pPage->maskPage = (u16)(pBt->pageSize - 1);
+  pPage->nOverflow = 0;
+  pPage->cellOffset = pPage->hdrOffset + 8 + pPage->childPtrSize;
+  pPage->aCellIdx = data + pPage->childPtrSize + 8;
+  pPage->aDataEnd = pPage->aData + pBt->pageSize;
+  pPage->aDataOfst = pPage->aData + pPage->childPtrSize;
+  /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the
+  ** number of cells on the page. */
+  pPage->nCell = get2byte(&data[3]);
+  if( pPage->nCell>MX_CELL(pBt) ){
+    /* To many cells for a single page.  The page must be corrupt */
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  testcase( pPage->nCell==MX_CELL(pBt) );
+  /* EVIDENCE-OF: R-24089-57979 If a page contains no cells (which is only
+  ** possible for a root page of a table that contains no rows) then the
+  ** offset to the cell content area will equal the page size minus the
+  ** bytes of reserved space. */
+  assert( pPage->nCell>0
+       || get2byteNotZero(&data[5])==(int)pBt->usableSize
+       || CORRUPT_DB );
+  pPage->nFree = -1;  /* Indicate that this value is yet uncomputed */
+  pPage->isInit = 1;
+  if( pBt->db->flags & SQLITE_CellSizeCk ){
+    return btreeCellSizeCheck(pPage);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Set up a raw page so that it looks like a database page holding
+** no entries.
+*/
+static void zeroPage(MemPage *pPage, int flags){
+  unsigned char *data = pPage->aData;
+  BtShared *pBt = pPage->pBt;
+  u8 hdr = pPage->hdrOffset;
+  u16 first;
+
+  assert( sqlite3PagerPagenumber(pPage->pDbPage)==pPage->pgno || CORRUPT_DB );
+  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
+  assert( sqlite3PagerGetData(pPage->pDbPage) == data );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pBt->btsFlags & BTS_FAST_SECURE ){
+    memset(&data[hdr], 0, pBt->usableSize - hdr);
+  }
+  data[hdr] = (char)flags;
+  first = hdr + ((flags&PTF_LEAF)==0 ? 12 : 8);
+  memset(&data[hdr+1], 0, 4);
+  data[hdr+7] = 0;
+  put2byte(&data[hdr+5], pBt->usableSize);
+  pPage->nFree = (u16)(pBt->usableSize - first);
+  decodeFlags(pPage, flags);
+  pPage->cellOffset = first;
+  pPage->aDataEnd = &data[pBt->pageSize];
+  pPage->aCellIdx = &data[first];
+  pPage->aDataOfst = &data[pPage->childPtrSize];
+  pPage->nOverflow = 0;
+  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
+  pPage->maskPage = (u16)(pBt->pageSize - 1);
+  pPage->nCell = 0;
+  pPage->isInit = 1;
+}
+
+
+/*
+** Convert a DbPage obtained from the pager into a MemPage used by
+** the btree layer.
+*/
+static MemPage *btreePageFromDbPage(DbPage *pDbPage, Pgno pgno, BtShared *pBt){
+  MemPage *pPage = (MemPage*)sqlite3PagerGetExtra(pDbPage);
+  if( pgno!=pPage->pgno ){
+    pPage->aData = sqlite3PagerGetData(pDbPage);
+    pPage->pDbPage = pDbPage;
+    pPage->pBt = pBt;
+    pPage->pgno = pgno;
+    pPage->hdrOffset = pgno==1 ? 100 : 0;
+  }
+  assert( pPage->aData==sqlite3PagerGetData(pDbPage) );
+  return pPage;
+}
+
+/*
+** Get a page from the pager.  Initialize the MemPage.pBt and
+** MemPage.aData elements if needed.  See also: btreeGetUnusedPage().
+**
+** If the PAGER_GET_NOCONTENT flag is set, it means that we do not care
+** about the content of the page at this time.  So do not go to the disk
+** to fetch the content.  Just fill in the content with zeros for now.
+** If in the future we call sqlite3PagerWrite() on this page, that
+** means we have started to be concerned about content and the disk
+** read should occur at that point.
+*/
+static int btreeGetPage(
+  BtShared *pBt,       /* The btree */
+  Pgno pgno,           /* Number of the page to fetch */
+  MemPage **ppPage,    /* Return the page in this parameter */
+  int flags            /* PAGER_GET_NOCONTENT or PAGER_GET_READONLY */
+){
+  int rc;
+  DbPage *pDbPage;
+
+  assert( flags==0 || flags==PAGER_GET_NOCONTENT || flags==PAGER_GET_READONLY );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  rc = sqlite3PagerGet(pBt->pPager, pgno, (DbPage**)&pDbPage, flags);
+  if( rc ) return rc;
+  *ppPage = btreePageFromDbPage(pDbPage, pgno, pBt);
+  return SQLITE_OK;
+}
+
+/*
+** Retrieve a page from the pager cache. If the requested page is not
+** already in the pager cache return NULL. Initialize the MemPage.pBt and
+** MemPage.aData elements if needed.
+*/
+static MemPage *btreePageLookup(BtShared *pBt, Pgno pgno){
+  DbPage *pDbPage;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  pDbPage = sqlite3PagerLookup(pBt->pPager, pgno);
+  if( pDbPage ){
+    return btreePageFromDbPage(pDbPage, pgno, pBt);
+  }
+  return 0;
+}
+
+/*
+** Return the size of the database file in pages. If there is any kind of
+** error, return ((unsigned int)-1).
+*/
+static Pgno btreePagecount(BtShared *pBt){
+  return pBt->nPage;
+}
+SQLITE_PRIVATE Pgno sqlite3BtreeLastPage(Btree *p){
+  assert( sqlite3BtreeHoldsMutex(p) );
+  return btreePagecount(p->pBt);
+}
+
+/*
+** Get a page from the pager and initialize it.
+*/
+static int getAndInitPage(
+  BtShared *pBt,                  /* The database file */
+  Pgno pgno,                      /* Number of the page to get */
+  MemPage **ppPage,               /* Write the page pointer here */
+  int bReadOnly                   /* True for a read-only page */
+){
+  int rc;
+  DbPage *pDbPage;
+  MemPage *pPage;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+
+  if( pgno>btreePagecount(pBt) ){
+    *ppPage = 0;
+    return SQLITE_CORRUPT_BKPT;
+  }
+  rc = sqlite3PagerGet(pBt->pPager, pgno, (DbPage**)&pDbPage, bReadOnly);
+  if( rc ){
+    *ppPage = 0;
+    return rc;
+  }
+  pPage = (MemPage*)sqlite3PagerGetExtra(pDbPage);
+  if( pPage->isInit==0 ){
+    btreePageFromDbPage(pDbPage, pgno, pBt);
+    rc = btreeInitPage(pPage);
+    if( rc!=SQLITE_OK ){
+      releasePage(pPage);
+      *ppPage = 0;
+      return rc;
+    }
+  }
+  assert( pPage->pgno==pgno || CORRUPT_DB );
+  assert( pPage->aData==sqlite3PagerGetData(pDbPage) );
+  *ppPage = pPage;
+  return SQLITE_OK;
+}
+
+/*
+** Release a MemPage.  This should be called once for each prior
+** call to btreeGetPage.
+**
+** Page1 is a special case and must be released using releasePageOne().
+*/
+static void releasePageNotNull(MemPage *pPage){
+  assert( pPage->aData );
+  assert( pPage->pBt );
+  assert( pPage->pDbPage!=0 );
+  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
+  assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  sqlite3PagerUnrefNotNull(pPage->pDbPage);
+}
+static void releasePage(MemPage *pPage){
+  if( pPage ) releasePageNotNull(pPage);
+}
+static void releasePageOne(MemPage *pPage){
+  assert( pPage!=0 );
+  assert( pPage->aData );
+  assert( pPage->pBt );
+  assert( pPage->pDbPage!=0 );
+  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
+  assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  sqlite3PagerUnrefPageOne(pPage->pDbPage);
+}
+
+/*
+** Get an unused page.
+**
+** This works just like btreeGetPage() with the addition:
+**
+**   *  If the page is already in use for some other purpose, immediately
+**      release it and return an SQLITE_CURRUPT error.
+**   *  Make sure the isInit flag is clear
+*/
+static int btreeGetUnusedPage(
+  BtShared *pBt,       /* The btree */
+  Pgno pgno,           /* Number of the page to fetch */
+  MemPage **ppPage,    /* Return the page in this parameter */
+  int flags            /* PAGER_GET_NOCONTENT or PAGER_GET_READONLY */
+){
+  int rc = btreeGetPage(pBt, pgno, ppPage, flags);
+  if( rc==SQLITE_OK ){
+    if( sqlite3PagerPageRefcount((*ppPage)->pDbPage)>1 ){
+      releasePage(*ppPage);
+      *ppPage = 0;
+      return SQLITE_CORRUPT_BKPT;
+    }
+    (*ppPage)->isInit = 0;
+  }else{
+    *ppPage = 0;
+  }
+  return rc;
+}
+
+
+/*
+** During a rollback, when the pager reloads information into the cache
+** so that the cache is restored to its original state at the start of
+** the transaction, for each page restored this routine is called.
+**
+** This routine needs to reset the extra data section at the end of the
+** page to agree with the restored data.
+*/
+static void pageReinit(DbPage *pData){
+  MemPage *pPage;
+  pPage = (MemPage *)sqlite3PagerGetExtra(pData);
+  assert( sqlite3PagerPageRefcount(pData)>0 );
+  if( pPage->isInit ){
+    assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+    pPage->isInit = 0;
+    if( sqlite3PagerPageRefcount(pData)>1 ){
+      /* pPage might not be a btree page;  it might be an overflow page
+      ** or ptrmap page or a free page.  In those cases, the following
+      ** call to btreeInitPage() will likely return SQLITE_CORRUPT.
+      ** But no harm is done by this.  And it is very important that
+      ** btreeInitPage() be called on every btree page so we make
+      ** the call for every page that comes in for re-initializing. */
+      btreeInitPage(pPage);
+    }
+  }
+}
+
+/*
+** Invoke the busy handler for a btree.
+*/
+static int btreeInvokeBusyHandler(void *pArg){
+  BtShared *pBt = (BtShared*)pArg;
+  assert( pBt->db );
+  assert( sqlite3_mutex_held(pBt->db->mutex) );
+  return sqlite3InvokeBusyHandler(&pBt->db->busyHandler);
+}
+
+/*
+** Open a database file.
+**
+** zFilename is the name of the database file.  If zFilename is NULL
+** then an ephemeral database is created.  The ephemeral database might
+** be exclusively in memory, or it might use a disk-based memory cache.
+** Either way, the ephemeral database will be automatically deleted
+** when sqlite3BtreeClose() is called.
+**
+** If zFilename is ":memory:" then an in-memory database is created
+** that is automatically destroyed when it is closed.
+**
+** The "flags" parameter is a bitmask that might contain bits like
+** BTREE_OMIT_JOURNAL and/or BTREE_MEMORY.
+**
+** If the database is already opened in the same database connection
+** and we are in shared cache mode, then the open will fail with an
+** SQLITE_CONSTRAINT error.  We cannot allow two or more BtShared
+** objects in the same database connection since doing so will lead
+** to problems with locking.
+*/
+SQLITE_PRIVATE int sqlite3BtreeOpen(
+  sqlite3_vfs *pVfs,      /* VFS to use for this b-tree */
+  const char *zFilename,  /* Name of the file containing the BTree database */
+  sqlite3 *db,            /* Associated database handle */
+  Btree **ppBtree,        /* Pointer to new Btree object written here */
+  int flags,              /* Options */
+  int vfsFlags            /* Flags passed through to sqlite3_vfs.xOpen() */
+){
+  BtShared *pBt = 0;             /* Shared part of btree structure */
+  Btree *p;                      /* Handle to return */
+  sqlite3_mutex *mutexOpen = 0;  /* Prevents a race condition. Ticket #3537 */
+  int rc = SQLITE_OK;            /* Result code from this function */
+  u8 nReserve;                   /* Byte of unused space on each page */
+  unsigned char zDbHeader[100];  /* Database header content */
+
+  /* True if opening an ephemeral, temporary database */
+  const int isTempDb = zFilename==0 || zFilename[0]==0;
+
+  /* Set the variable isMemdb to true for an in-memory database, or
+  ** false for a file-based database.
+  */
+#ifdef SQLITE_OMIT_MEMORYDB
+  const int isMemdb = 0;
+#else
+  const int isMemdb = (zFilename && strcmp(zFilename, ":memory:")==0)
+                       || (isTempDb && sqlite3TempInMemory(db))
+                       || (vfsFlags & SQLITE_OPEN_MEMORY)!=0;
+#endif
+
+  assert( db!=0 );
+  assert( pVfs!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( (flags&0xff)==flags );   /* flags fit in 8 bits */
+
+  /* Only a BTREE_SINGLE database can be BTREE_UNORDERED */
+  assert( (flags & BTREE_UNORDERED)==0 || (flags & BTREE_SINGLE)!=0 );
+
+  /* A BTREE_SINGLE database is always a temporary and/or ephemeral */
+  assert( (flags & BTREE_SINGLE)==0 || isTempDb );
+
+  if( isMemdb ){
+    flags |= BTREE_MEMORY;
+  }
+  if( (vfsFlags & SQLITE_OPEN_MAIN_DB)!=0 && (isMemdb || isTempDb) ){
+    vfsFlags = (vfsFlags & ~SQLITE_OPEN_MAIN_DB) | SQLITE_OPEN_TEMP_DB;
+  }
+  p = sqlite3MallocZero(sizeof(Btree));
+  if( !p ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  p->inTrans = TRANS_NONE;
+  p->db = db;
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  p->lock.pBtree = p;
+  p->lock.iTable = 1;
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
+  /*
+  ** If this Btree is a candidate for shared cache, try to find an
+  ** existing BtShared object that we can share with
+  */
+  if( isTempDb==0 && (isMemdb==0 || (vfsFlags&SQLITE_OPEN_URI)!=0) ){
+    if( vfsFlags & SQLITE_OPEN_SHAREDCACHE ){
+      int nFilename = sqlite3Strlen30(zFilename)+1;
+      int nFullPathname = pVfs->mxPathname+1;
+      char *zFullPathname = sqlite3Malloc(MAX(nFullPathname,nFilename));
+      MUTEX_LOGIC( sqlite3_mutex *mutexShared; )
+
+      p->sharable = 1;
+      if( !zFullPathname ){
+        sqlite3_free(p);
+        return SQLITE_NOMEM_BKPT;
+      }
+      if( isMemdb ){
+        memcpy(zFullPathname, zFilename, nFilename);
+      }else{
+        rc = sqlite3OsFullPathname(pVfs, zFilename,
+                                   nFullPathname, zFullPathname);
+        if( rc ){
+          if( rc==SQLITE_OK_SYMLINK ){
+            rc = SQLITE_OK;
+          }else{
+            sqlite3_free(zFullPathname);
+            sqlite3_free(p);
+            return rc;
+          }
+        }
+      }
+#if SQLITE_THREADSAFE
+      mutexOpen = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_OPEN);
+      sqlite3_mutex_enter(mutexOpen);
+      mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+      sqlite3_mutex_enter(mutexShared);
+#endif
+      for(pBt=GLOBAL(BtShared*,sqlite3SharedCacheList); pBt; pBt=pBt->pNext){
+        assert( pBt->nRef>0 );
+        if( 0==strcmp(zFullPathname, sqlite3PagerFilename(pBt->pPager, 0))
+                 && sqlite3PagerVfs(pBt->pPager)==pVfs ){
+          int iDb;
+          for(iDb=db->nDb-1; iDb>=0; iDb--){
+            Btree *pExisting = db->aDb[iDb].pBt;
+            if( pExisting && pExisting->pBt==pBt ){
+              sqlite3_mutex_leave(mutexShared);
+              sqlite3_mutex_leave(mutexOpen);
+              sqlite3_free(zFullPathname);
+              sqlite3_free(p);
+              return SQLITE_CONSTRAINT;
+            }
+          }
+          p->pBt = pBt;
+          pBt->nRef++;
+          break;
+        }
+      }
+      sqlite3_mutex_leave(mutexShared);
+      sqlite3_free(zFullPathname);
+    }
+#ifdef SQLITE_DEBUG
+    else{
+      /* In debug mode, we mark all persistent databases as sharable
+      ** even when they are not.  This exercises the locking code and
+      ** gives more opportunity for asserts(sqlite3_mutex_held())
+      ** statements to find locking problems.
+      */
+      p->sharable = 1;
+    }
+#endif
+  }
+#endif
+  if( pBt==0 ){
+    /*
+    ** The following asserts make sure that structures used by the btree are
+    ** the right size.  This is to guard against size changes that result
+    ** when compiling on a different architecture.
+    */
+    assert( sizeof(i64)==8 );
+    assert( sizeof(u64)==8 );
+    assert( sizeof(u32)==4 );
+    assert( sizeof(u16)==2 );
+    assert( sizeof(Pgno)==4 );
+
+    /* Suppress false-positive compiler warning from PVS-Studio */
+    memset(&zDbHeader[16], 0, 8);
+
+    pBt = sqlite3MallocZero( sizeof(*pBt) );
+    if( pBt==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto btree_open_out;
+    }
+    rc = sqlite3PagerOpen(pVfs, &pBt->pPager, zFilename,
+                          sizeof(MemPage), flags, vfsFlags, pageReinit);
+    if( rc==SQLITE_OK ){
+      sqlite3PagerSetMmapLimit(pBt->pPager, db->szMmap);
+      rc = sqlite3PagerReadFileheader(pBt->pPager,sizeof(zDbHeader),zDbHeader);
+    }
+    if( rc!=SQLITE_OK ){
+      goto btree_open_out;
+    }
+    pBt->openFlags = (u8)flags;
+    pBt->db = db;
+    sqlite3PagerSetBusyHandler(pBt->pPager, btreeInvokeBusyHandler, pBt);
+    p->pBt = pBt;
+
+    pBt->pCursor = 0;
+    pBt->pPage1 = 0;
+    if( sqlite3PagerIsreadonly(pBt->pPager) ) pBt->btsFlags |= BTS_READ_ONLY;
+#if defined(SQLITE_SECURE_DELETE)
+    pBt->btsFlags |= BTS_SECURE_DELETE;
+#elif defined(SQLITE_FAST_SECURE_DELETE)
+    pBt->btsFlags |= BTS_OVERWRITE;
+#endif
+    /* EVIDENCE-OF: R-51873-39618 The page size for a database file is
+    ** determined by the 2-byte integer located at an offset of 16 bytes from
+    ** the beginning of the database file. */
+    pBt->pageSize = (zDbHeader[16]<<8) | (zDbHeader[17]<<16);
+    if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
+         || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
+      pBt->pageSize = 0;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      /* If the magic name ":memory:" will create an in-memory database, then
+      ** leave the autoVacuum mode at 0 (do not auto-vacuum), even if
+      ** SQLITE_DEFAULT_AUTOVACUUM is true. On the other hand, if
+      ** SQLITE_OMIT_MEMORYDB has been defined, then ":memory:" is just a
+      ** regular file-name. In this case the auto-vacuum applies as per normal.
+      */
+      if( zFilename && !isMemdb ){
+        pBt->autoVacuum = (SQLITE_DEFAULT_AUTOVACUUM ? 1 : 0);
+        pBt->incrVacuum = (SQLITE_DEFAULT_AUTOVACUUM==2 ? 1 : 0);
+      }
+#endif
+      nReserve = 0;
+    }else{
+      /* EVIDENCE-OF: R-37497-42412 The size of the reserved region is
+      ** determined by the one-byte unsigned integer found at an offset of 20
+      ** into the database file header. */
+      nReserve = zDbHeader[20];
+      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
+      pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
+#endif
+    }
+    rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
+    if( rc ) goto btree_open_out;
+    pBt->usableSize = pBt->pageSize - nReserve;
+    assert( (pBt->pageSize & 7)==0 );  /* 8-byte alignment of pageSize */
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
+    /* Add the new BtShared object to the linked list sharable BtShareds.
+    */
+    pBt->nRef = 1;
+    if( p->sharable ){
+      MUTEX_LOGIC( sqlite3_mutex *mutexShared; )
+      MUTEX_LOGIC( mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);)
+      if( SQLITE_THREADSAFE && sqlite3GlobalConfig.bCoreMutex ){
+        pBt->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_FAST);
+        if( pBt->mutex==0 ){
+          rc = SQLITE_NOMEM_BKPT;
+          goto btree_open_out;
+        }
+      }
+      sqlite3_mutex_enter(mutexShared);
+      pBt->pNext = GLOBAL(BtShared*,sqlite3SharedCacheList);
+      GLOBAL(BtShared*,sqlite3SharedCacheList) = pBt;
+      sqlite3_mutex_leave(mutexShared);
+    }
+#endif
+  }
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
+  /* If the new Btree uses a sharable pBtShared, then link the new
+  ** Btree into the list of all sharable Btrees for the same connection.
+  ** The list is kept in ascending order by pBt address.
+  */
+  if( p->sharable ){
+    int i;
+    Btree *pSib;
+    for(i=0; i<db->nDb; i++){
+      if( (pSib = db->aDb[i].pBt)!=0 && pSib->sharable ){
+        while( pSib->pPrev ){ pSib = pSib->pPrev; }
+        if( (uptr)p->pBt<(uptr)pSib->pBt ){
+          p->pNext = pSib;
+          p->pPrev = 0;
+          pSib->pPrev = p;
+        }else{
+          while( pSib->pNext && (uptr)pSib->pNext->pBt<(uptr)p->pBt ){
+            pSib = pSib->pNext;
+          }
+          p->pNext = pSib->pNext;
+          p->pPrev = pSib;
+          if( p->pNext ){
+            p->pNext->pPrev = p;
+          }
+          pSib->pNext = p;
+        }
+        break;
+      }
+    }
+  }
+#endif
+  *ppBtree = p;
+
+btree_open_out:
+  if( rc!=SQLITE_OK ){
+    if( pBt && pBt->pPager ){
+      sqlite3PagerClose(pBt->pPager, 0);
+    }
+    sqlite3_free(pBt);
+    sqlite3_free(p);
+    *ppBtree = 0;
+  }else{
+    sqlite3_file *pFile;
+
+    /* If the B-Tree was successfully opened, set the pager-cache size to the
+    ** default value. Except, when opening on an existing shared pager-cache,
+    ** do not change the pager-cache size.
+    */
+    if( sqlite3BtreeSchema(p, 0, 0)==0 ){
+      sqlite3BtreeSetCacheSize(p, SQLITE_DEFAULT_CACHE_SIZE);
+    }
+
+    pFile = sqlite3PagerFile(pBt->pPager);
+    if( pFile->pMethods ){
+      sqlite3OsFileControlHint(pFile, SQLITE_FCNTL_PDB, (void*)&pBt->db);
+    }
+  }
+  if( mutexOpen ){
+    assert( sqlite3_mutex_held(mutexOpen) );
+    sqlite3_mutex_leave(mutexOpen);
+  }
+  assert( rc!=SQLITE_OK || sqlite3BtreeConnectionCount(*ppBtree)>0 );
+  return rc;
+}
+
+/*
+** Decrement the BtShared.nRef counter.  When it reaches zero,
+** remove the BtShared structure from the sharing list.  Return
+** true if the BtShared.nRef counter reaches zero and return
+** false if it is still positive.
+*/
+static int removeFromSharingList(BtShared *pBt){
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  MUTEX_LOGIC( sqlite3_mutex *pMainMtx; )
+  BtShared *pList;
+  int removed = 0;
+
+  assert( sqlite3_mutex_notheld(pBt->mutex) );
+  MUTEX_LOGIC( pMainMtx = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  sqlite3_mutex_enter(pMainMtx);
+  pBt->nRef--;
+  if( pBt->nRef<=0 ){
+    if( GLOBAL(BtShared*,sqlite3SharedCacheList)==pBt ){
+      GLOBAL(BtShared*,sqlite3SharedCacheList) = pBt->pNext;
+    }else{
+      pList = GLOBAL(BtShared*,sqlite3SharedCacheList);
+      while( ALWAYS(pList) && pList->pNext!=pBt ){
+        pList=pList->pNext;
+      }
+      if( ALWAYS(pList) ){
+        pList->pNext = pBt->pNext;
+      }
+    }
+    if( SQLITE_THREADSAFE ){
+      sqlite3_mutex_free(pBt->mutex);
+    }
+    removed = 1;
+  }
+  sqlite3_mutex_leave(pMainMtx);
+  return removed;
+#else
+  return 1;
+#endif
+}
+
+/*
+** Make sure pBt->pTmpSpace points to an allocation of
+** MX_CELL_SIZE(pBt) bytes with a 4-byte prefix for a left-child
+** pointer.
+*/
+static SQLITE_NOINLINE int allocateTempSpace(BtShared *pBt){
+  assert( pBt!=0 );
+  assert( pBt->pTmpSpace==0 );
+  /* This routine is called only by btreeCursor() when allocating the
+  ** first write cursor for the BtShared object */
+  assert( pBt->pCursor!=0 && (pBt->pCursor->curFlags & BTCF_WriteFlag)!=0 );
+  pBt->pTmpSpace = sqlite3PageMalloc( pBt->pageSize );
+  if( pBt->pTmpSpace==0 ){
+    BtCursor *pCur = pBt->pCursor;
+    pBt->pCursor = pCur->pNext;  /* Unlink the cursor */
+    memset(pCur, 0, sizeof(*pCur));
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  /* One of the uses of pBt->pTmpSpace is to format cells before
+  ** inserting them into a leaf page (function fillInCell()). If
+  ** a cell is less than 4 bytes in size, it is rounded up to 4 bytes
+  ** by the various routines that manipulate binary cells. Which
+  ** can mean that fillInCell() only initializes the first 2 or 3
+  ** bytes of pTmpSpace, but that the first 4 bytes are copied from
+  ** it into a database page. This is not actually a problem, but it
+  ** does cause a valgrind error when the 1 or 2 bytes of uninitialized
+  ** data is passed to system call write(). So to avoid this error,
+  ** zero the first 4 bytes of temp space here.
+  **
+  ** Also:  Provide four bytes of initialized space before the
+  ** beginning of pTmpSpace as an area available to prepend the
+  ** left-child pointer to the beginning of a cell.
+  */
+  memset(pBt->pTmpSpace, 0, 8);
+  pBt->pTmpSpace += 4;
+  return SQLITE_OK;
+}
+
+/*
+** Free the pBt->pTmpSpace allocation
+*/
+static void freeTempSpace(BtShared *pBt){
+  if( pBt->pTmpSpace ){
+    pBt->pTmpSpace -= 4;
+    sqlite3PageFree(pBt->pTmpSpace);
+    pBt->pTmpSpace = 0;
+  }
+}
+
+/*
+** Close an open database and invalidate all cursors.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClose(Btree *p){
+  BtShared *pBt = p->pBt;
+
+  /* Close all cursors opened via this handle.  */
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+
+  /* Verify that no other cursors have this Btree open */
+#ifdef SQLITE_DEBUG
+  {
+    BtCursor *pCur = pBt->pCursor;
+    while( pCur ){
+      BtCursor *pTmp = pCur;
+      pCur = pCur->pNext;
+      assert( pTmp->pBtree!=p );
+
+    }
+  }
+#endif
+
+  /* Rollback any active transaction and free the handle structure.
+  ** The call to sqlite3BtreeRollback() drops any table-locks held by
+  ** this handle.
+  */
+  sqlite3BtreeRollback(p, SQLITE_OK, 0);
+  sqlite3BtreeLeave(p);
+
+  /* If there are still other outstanding references to the shared-btree
+  ** structure, return now. The remainder of this procedure cleans
+  ** up the shared-btree.
+  */
+  assert( p->wantToLock==0 && p->locked==0 );
+  if( !p->sharable || removeFromSharingList(pBt) ){
+    /* The pBt is no longer on the sharing list, so we can access
+    ** it without having to hold the mutex.
+    **
+    ** Clean out and delete the BtShared object.
+    */
+    assert( !pBt->pCursor );
+    sqlite3PagerClose(pBt->pPager, p->db);
+    if( pBt->xFreeSchema && pBt->pSchema ){
+      pBt->xFreeSchema(pBt->pSchema);
+    }
+    sqlite3DbFree(0, pBt->pSchema);
+    freeTempSpace(pBt);
+    sqlite3_free(pBt);
+  }
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  assert( p->wantToLock==0 );
+  assert( p->locked==0 );
+  if( p->pPrev ) p->pPrev->pNext = p->pNext;
+  if( p->pNext ) p->pNext->pPrev = p->pPrev;
+#endif
+
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Change the "soft" limit on the number of pages in the cache.
+** Unused and unmodified pages will be recycled when the number of
+** pages in the cache exceeds this soft limit.  But the size of the
+** cache is allowed to grow larger than this limit if it contains
+** dirty pages or pages still in active use.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree *p, int mxPage){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  sqlite3PagerSetCachesize(pBt->pPager, mxPage);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Change the "spill" limit on the number of pages in the cache.
+** If the number of pages exceeds this limit during a write transaction,
+** the pager might attempt to "spill" pages to the journal early in
+** order to free up memory.
+**
+** The value returned is the current spill size.  If zero is passed
+** as an argument, no changes are made to the spill size setting, so
+** using mxPage of 0 is a way to query the current spill size.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetSpillSize(Btree *p, int mxPage){
+  BtShared *pBt = p->pBt;
+  int res;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  res = sqlite3PagerSetSpillsize(pBt->pPager, mxPage);
+  sqlite3BtreeLeave(p);
+  return res;
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/*
+** Change the limit on the amount of the database file that may be
+** memory mapped.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetMmapLimit(Btree *p, sqlite3_int64 szMmap){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  sqlite3PagerSetMmapLimit(pBt->pPager, szMmap);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+
+/*
+** Change the way data is synced to disk in order to increase or decrease
+** how well the database resists damage due to OS crashes and power
+** failures.  Level 1 is the same as asynchronous (no syncs() occur and
+** there is a high probability of damage)  Level 2 is the default.  There
+** is a very low but non-zero probability of damage.  Level 3 reduces the
+** probability of damage to near zero but with a write performance reduction.
+*/
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+SQLITE_PRIVATE int sqlite3BtreeSetPagerFlags(
+  Btree *p,              /* The btree to set the safety level on */
+  unsigned pgFlags       /* Various PAGER_* flags */
+){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  sqlite3PagerSetFlags(pBt->pPager, pgFlags);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Change the default pages size and the number of reserved bytes per page.
+** Or, if the page size has already been fixed, return SQLITE_READONLY
+** without changing anything.
+**
+** The page size must be a power of 2 between 512 and 65536.  If the page
+** size supplied does not meet this constraint then the page size is not
+** changed.
+**
+** Page sizes are constrained to be a power of two so that the region
+** of the database file used for locking (beginning at PENDING_BYTE,
+** the first byte past the 1GB boundary, 0x40000000) needs to occur
+** at the beginning of a page.
+**
+** If parameter nReserve is less than zero, then the number of reserved
+** bytes per page is left unchanged.
+**
+** If the iFix!=0 then the BTS_PAGESIZE_FIXED flag is set so that the page size
+** and autovacuum mode can no longer be changed.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
+  int rc = SQLITE_OK;
+  int x;
+  BtShared *pBt = p->pBt;
+  assert( nReserve>=0 && nReserve<=255 );
+  sqlite3BtreeEnter(p);
+  pBt->nReserveWanted = nReserve;
+  x = pBt->pageSize - pBt->usableSize;
+  if( nReserve<x ) nReserve = x;
+  if( pBt->btsFlags & BTS_PAGESIZE_FIXED ){
+    sqlite3BtreeLeave(p);
+    return SQLITE_READONLY;
+  }
+  assert( nReserve>=0 && nReserve<=255 );
+  if( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE &&
+        ((pageSize-1)&pageSize)==0 ){
+    assert( (pageSize & 7)==0 );
+    assert( !pBt->pCursor );
+    if( nReserve>32 && pageSize==512 ) pageSize = 1024;
+    pBt->pageSize = (u32)pageSize;
+    freeTempSpace(pBt);
+  }
+  rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
+  pBt->usableSize = pBt->pageSize - (u16)nReserve;
+  if( iFix ) pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Return the currently defined page size
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree *p){
+  return p->pBt->pageSize;
+}
+
+/*
+** This function is similar to sqlite3BtreeGetReserve(), except that it
+** may only be called if it is guaranteed that the b-tree mutex is already
+** held.
+**
+** This is useful in one special case in the backup API code where it is
+** known that the shared b-tree mutex is held, but the mutex on the
+** database handle that owns *p is not. In this case if sqlite3BtreeEnter()
+** were to be called, it might collide with some other operation on the
+** database handle that owns *p, causing undefined behavior.
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetReserveNoMutex(Btree *p){
+  int n;
+  assert( sqlite3_mutex_held(p->pBt->mutex) );
+  n = p->pBt->pageSize - p->pBt->usableSize;
+  return n;
+}
+
+/*
+** Return the number of bytes of space at the end of every page that
+** are intentionally left unused.  This is the "reserved" space that is
+** sometimes used by extensions.
+**
+** The value returned is the larger of the current reserve size and
+** the latest reserve size requested by SQLITE_FILECTRL_RESERVE_BYTES.
+** The amount of reserve can only grow - never shrink.
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetRequestedReserve(Btree *p){
+  int n1, n2;
+  sqlite3BtreeEnter(p);
+  n1 = (int)p->pBt->nReserveWanted;
+  n2 = sqlite3BtreeGetReserveNoMutex(p);
+  sqlite3BtreeLeave(p);
+  return n1>n2 ? n1 : n2;
+}
+
+
+/*
+** Set the maximum page count for a database if mxPage is positive.
+** No changes are made if mxPage is 0 or negative.
+** Regardless of the value of mxPage, return the maximum page count.
+*/
+SQLITE_PRIVATE Pgno sqlite3BtreeMaxPageCount(Btree *p, Pgno mxPage){
+  Pgno n;
+  sqlite3BtreeEnter(p);
+  n = sqlite3PagerMaxPageCount(p->pBt->pPager, mxPage);
+  sqlite3BtreeLeave(p);
+  return n;
+}
+
+/*
+** Change the values for the BTS_SECURE_DELETE and BTS_OVERWRITE flags:
+**
+**    newFlag==0       Both BTS_SECURE_DELETE and BTS_OVERWRITE are cleared
+**    newFlag==1       BTS_SECURE_DELETE set and BTS_OVERWRITE is cleared
+**    newFlag==2       BTS_SECURE_DELETE cleared and BTS_OVERWRITE is set
+**    newFlag==(-1)    No changes
+**
+** This routine acts as a query if newFlag is less than zero
+**
+** With BTS_OVERWRITE set, deleted content is overwritten by zeros, but
+** freelist leaf pages are not written back to the database.  Thus in-page
+** deleted content is cleared, but freelist deleted content is not.
+**
+** With BTS_SECURE_DELETE, operation is like BTS_OVERWRITE with the addition
+** that freelist leaf pages are written back into the database, increasing
+** the amount of disk I/O.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSecureDelete(Btree *p, int newFlag){
+  int b;
+  if( p==0 ) return 0;
+  sqlite3BtreeEnter(p);
+  assert( BTS_OVERWRITE==BTS_SECURE_DELETE*2 );
+  assert( BTS_FAST_SECURE==(BTS_OVERWRITE|BTS_SECURE_DELETE) );
+  if( newFlag>=0 ){
+    p->pBt->btsFlags &= ~BTS_FAST_SECURE;
+    p->pBt->btsFlags |= BTS_SECURE_DELETE*newFlag;
+  }
+  b = (p->pBt->btsFlags & BTS_FAST_SECURE)/BTS_SECURE_DELETE;
+  sqlite3BtreeLeave(p);
+  return b;
+}
+
+/*
+** Change the 'auto-vacuum' property of the database. If the 'autoVacuum'
+** parameter is non-zero, then auto-vacuum mode is enabled. If zero, it
+** is disabled. The default value for the auto-vacuum property is
+** determined by the SQLITE_DEFAULT_AUTOVACUUM macro.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *p, int autoVacuum){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  return SQLITE_READONLY;
+#else
+  BtShared *pBt = p->pBt;
+  int rc = SQLITE_OK;
+  u8 av = (u8)autoVacuum;
+
+  sqlite3BtreeEnter(p);
+  if( (pBt->btsFlags & BTS_PAGESIZE_FIXED)!=0 && (av ?1:0)!=pBt->autoVacuum ){
+    rc = SQLITE_READONLY;
+  }else{
+    pBt->autoVacuum = av ?1:0;
+    pBt->incrVacuum = av==2 ?1:0;
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+#endif
+}
+
+/*
+** Return the value of the 'auto-vacuum' property. If auto-vacuum is
+** enabled 1 is returned. Otherwise 0.
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *p){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  return BTREE_AUTOVACUUM_NONE;
+#else
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = (
+    (!p->pBt->autoVacuum)?BTREE_AUTOVACUUM_NONE:
+    (!p->pBt->incrVacuum)?BTREE_AUTOVACUUM_FULL:
+    BTREE_AUTOVACUUM_INCR
+  );
+  sqlite3BtreeLeave(p);
+  return rc;
+#endif
+}
+
+/*
+** If the user has not set the safety-level for this database connection
+** using "PRAGMA synchronous", and if the safety-level is not already
+** set to the value passed to this function as the second parameter,
+** set it so.
+*/
+#if SQLITE_DEFAULT_SYNCHRONOUS!=SQLITE_DEFAULT_WAL_SYNCHRONOUS \
+    && !defined(SQLITE_OMIT_WAL)
+static void setDefaultSyncFlag(BtShared *pBt, u8 safety_level){
+  sqlite3 *db;
+  Db *pDb;
+  if( (db=pBt->db)!=0 && (pDb=db->aDb)!=0 ){
+    while( pDb->pBt==0 || pDb->pBt->pBt!=pBt ){ pDb++; }
+    if( pDb->bSyncSet==0
+     && pDb->safety_level!=safety_level
+     && pDb!=&db->aDb[1]
+    ){
+      pDb->safety_level = safety_level;
+      sqlite3PagerSetFlags(pBt->pPager,
+          pDb->safety_level | (db->flags & PAGER_FLAGS_MASK));
+    }
+  }
+}
+#else
+# define setDefaultSyncFlag(pBt,safety_level)
+#endif
+
+/* Forward declaration */
+static int newDatabase(BtShared*);
+
+
+/*
+** Get a reference to pPage1 of the database file.  This will
+** also acquire a readlock on that file.
+**
+** SQLITE_OK is returned on success.  If the file is not a
+** well-formed database file, then SQLITE_CORRUPT is returned.
+** SQLITE_BUSY is returned if the database is locked.  SQLITE_NOMEM
+** is returned if we run out of memory.
+*/
+static int lockBtree(BtShared *pBt){
+  int rc;              /* Result code from subfunctions */
+  MemPage *pPage1;     /* Page 1 of the database file */
+  u32 nPage;           /* Number of pages in the database */
+  u32 nPageFile = 0;   /* Number of pages in the database file */
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pBt->pPage1==0 );
+  rc = sqlite3PagerSharedLock(pBt->pPager);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = btreeGetPage(pBt, 1, &pPage1, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Do some checking to help insure the file we opened really is
+  ** a valid database file.
+  */
+  nPage = get4byte(28+(u8*)pPage1->aData);
+  sqlite3PagerPagecount(pBt->pPager, (int*)&nPageFile);
+  if( nPage==0 || memcmp(24+(u8*)pPage1->aData, 92+(u8*)pPage1->aData,4)!=0 ){
+    nPage = nPageFile;
+  }
+  if( (pBt->db->flags & SQLITE_ResetDatabase)!=0 ){
+    nPage = 0;
+  }
+  if( nPage>0 ){
+    u32 pageSize;
+    u32 usableSize;
+    u8 *page1 = pPage1->aData;
+    rc = SQLITE_NOTADB;
+    /* EVIDENCE-OF: R-43737-39999 Every valid SQLite database file begins
+    ** with the following 16 bytes (in hex): 53 51 4c 69 74 65 20 66 6f 72 6d
+    ** 61 74 20 33 00. */
+    if( memcmp(page1, zMagicHeader, 16)!=0 ){
+      goto page1_init_failed;
+    }
+
+#ifdef SQLITE_OMIT_WAL
+    if( page1[18]>1 ){
+      pBt->btsFlags |= BTS_READ_ONLY;
+    }
+    if( page1[19]>1 ){
+      goto page1_init_failed;
+    }
+#else
+    if( page1[18]>2 ){
+      pBt->btsFlags |= BTS_READ_ONLY;
+    }
+    if( page1[19]>2 ){
+      goto page1_init_failed;
+    }
+
+    /* If the read version is set to 2, this database should be accessed
+    ** in WAL mode. If the log is not already open, open it now. Then
+    ** return SQLITE_OK and return without populating BtShared.pPage1.
+    ** The caller detects this and calls this function again. This is
+    ** required as the version of page 1 currently in the page1 buffer
+    ** may not be the latest version - there may be a newer one in the log
+    ** file.
+    */
+    if( page1[19]==2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
+      int isOpen = 0;
+      rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
+      if( rc!=SQLITE_OK ){
+        goto page1_init_failed;
+      }else{
+        setDefaultSyncFlag(pBt, SQLITE_DEFAULT_WAL_SYNCHRONOUS+1);
+        if( isOpen==0 ){
+          releasePageOne(pPage1);
+          return SQLITE_OK;
+        }
+      }
+      rc = SQLITE_NOTADB;
+    }else{
+      setDefaultSyncFlag(pBt, SQLITE_DEFAULT_SYNCHRONOUS+1);
+    }
+#endif
+
+    /* EVIDENCE-OF: R-15465-20813 The maximum and minimum embedded payload
+    ** fractions and the leaf payload fraction values must be 64, 32, and 32.
+    **
+    ** The original design allowed these amounts to vary, but as of
+    ** version 3.6.0, we require them to be fixed.
+    */
+    if( memcmp(&page1[21], "\100\040\040",3)!=0 ){
+      goto page1_init_failed;
+    }
+    /* EVIDENCE-OF: R-51873-39618 The page size for a database file is
+    ** determined by the 2-byte integer located at an offset of 16 bytes from
+    ** the beginning of the database file. */
+    pageSize = (page1[16]<<8) | (page1[17]<<16);
+    /* EVIDENCE-OF: R-25008-21688 The size of a page is a power of two
+    ** between 512 and 65536 inclusive. */
+    if( ((pageSize-1)&pageSize)!=0
+     || pageSize>SQLITE_MAX_PAGE_SIZE
+     || pageSize<=256
+    ){
+      goto page1_init_failed;
+    }
+    assert( (pageSize & 7)==0 );
+    /* EVIDENCE-OF: R-59310-51205 The "reserved space" size in the 1-byte
+    ** integer at offset 20 is the number of bytes of space at the end of
+    ** each page to reserve for extensions.
+    **
+    ** EVIDENCE-OF: R-37497-42412 The size of the reserved region is
+    ** determined by the one-byte unsigned integer found at an offset of 20
+    ** into the database file header. */
+    usableSize = pageSize - page1[20];
+    if( (u32)pageSize!=pBt->pageSize ){
+      /* After reading the first page of the database assuming a page size
+      ** of BtShared.pageSize, we have discovered that the page-size is
+      ** actually pageSize. Unlock the database, leave pBt->pPage1 at
+      ** zero and return SQLITE_OK. The caller will call this function
+      ** again with the correct page-size.
+      */
+      releasePageOne(pPage1);
+      pBt->usableSize = usableSize;
+      pBt->pageSize = pageSize;
+      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+      freeTempSpace(pBt);
+      rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize,
+                                   pageSize-usableSize);
+      return rc;
+    }
+    if( nPage>nPageFile ){
+      if( sqlite3WritableSchema(pBt->db)==0 ){
+        rc = SQLITE_CORRUPT_BKPT;
+        goto page1_init_failed;
+      }else{
+        nPage = nPageFile;
+      }
+    }
+    /* EVIDENCE-OF: R-28312-64704 However, the usable size is not allowed to
+    ** be less than 480. In other words, if the page size is 512, then the
+    ** reserved space size cannot exceed 32. */
+    if( usableSize<480 ){
+      goto page1_init_failed;
+    }
+    pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+    pBt->pageSize = pageSize;
+    pBt->usableSize = usableSize;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    pBt->autoVacuum = (get4byte(&page1[36 + 4*4])?1:0);
+    pBt->incrVacuum = (get4byte(&page1[36 + 7*4])?1:0);
+#endif
+  }
+
+  /* maxLocal is the maximum amount of payload to store locally for
+  ** a cell.  Make sure it is small enough so that at least minFanout
+  ** cells can will fit on one page.  We assume a 10-byte page header.
+  ** Besides the payload, the cell must store:
+  **     2-byte pointer to the cell
+  **     4-byte child pointer
+  **     9-byte nKey value
+  **     4-byte nData value
+  **     4-byte overflow page pointer
+  ** So a cell consists of a 2-byte pointer, a header which is as much as
+  ** 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow
+  ** page pointer.
+  */
+  pBt->maxLocal = (u16)((pBt->usableSize-12)*64/255 - 23);
+  pBt->minLocal = (u16)((pBt->usableSize-12)*32/255 - 23);
+  pBt->maxLeaf = (u16)(pBt->usableSize - 35);
+  pBt->minLeaf = (u16)((pBt->usableSize-12)*32/255 - 23);
+  if( pBt->maxLocal>127 ){
+    pBt->max1bytePayload = 127;
+  }else{
+    pBt->max1bytePayload = (u8)pBt->maxLocal;
+  }
+  assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) );
+  pBt->pPage1 = pPage1;
+  pBt->nPage = nPage;
+  return SQLITE_OK;
+
+page1_init_failed:
+  releasePageOne(pPage1);
+  pBt->pPage1 = 0;
+  return rc;
+}
+
+#ifndef NDEBUG
+/*
+** Return the number of cursors open on pBt. This is for use
+** in assert() expressions, so it is only compiled if NDEBUG is not
+** defined.
+**
+** Only write cursors are counted if wrOnly is true.  If wrOnly is
+** false then all cursors are counted.
+**
+** For the purposes of this routine, a cursor is any cursor that
+** is capable of reading or writing to the database.  Cursors that
+** have been tripped into the CURSOR_FAULT state are not counted.
+*/
+static int countValidCursors(BtShared *pBt, int wrOnly){
+  BtCursor *pCur;
+  int r = 0;
+  for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
+    if( (wrOnly==0 || (pCur->curFlags & BTCF_WriteFlag)!=0)
+     && pCur->eState!=CURSOR_FAULT ) r++;
+  }
+  return r;
+}
+#endif
+
+/*
+** If there are no outstanding cursors and we are not in the middle
+** of a transaction but there is a read lock on the database, then
+** this routine unrefs the first page of the database file which
+** has the effect of releasing the read lock.
+**
+** If there is a transaction in progress, this routine is a no-op.
+*/
+static void unlockBtreeIfUnused(BtShared *pBt){
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( countValidCursors(pBt,0)==0 || pBt->inTransaction>TRANS_NONE );
+  if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){
+    MemPage *pPage1 = pBt->pPage1;
+    assert( pPage1->aData );
+    assert( sqlite3PagerRefcount(pBt->pPager)==1 );
+    pBt->pPage1 = 0;
+    releasePageOne(pPage1);
+  }
+}
+
+/*
+** If pBt points to an empty file then convert that empty file
+** into a new empty database by initializing the first page of
+** the database.
+*/
+static int newDatabase(BtShared *pBt){
+  MemPage *pP1;
+  unsigned char *data;
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pBt->nPage>0 ){
+    return SQLITE_OK;
+  }
+  pP1 = pBt->pPage1;
+  assert( pP1!=0 );
+  data = pP1->aData;
+  rc = sqlite3PagerWrite(pP1->pDbPage);
+  if( rc ) return rc;
+  memcpy(data, zMagicHeader, sizeof(zMagicHeader));
+  assert( sizeof(zMagicHeader)==16 );
+  data[16] = (u8)((pBt->pageSize>>8)&0xff);
+  data[17] = (u8)((pBt->pageSize>>16)&0xff);
+  data[18] = 1;
+  data[19] = 1;
+  assert( pBt->usableSize<=pBt->pageSize && pBt->usableSize+255>=pBt->pageSize);
+  data[20] = (u8)(pBt->pageSize - pBt->usableSize);
+  data[21] = 64;
+  data[22] = 32;
+  data[23] = 32;
+  memset(&data[24], 0, 100-24);
+  zeroPage(pP1, PTF_INTKEY|PTF_LEAF|PTF_LEAFDATA );
+  pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  assert( pBt->autoVacuum==1 || pBt->autoVacuum==0 );
+  assert( pBt->incrVacuum==1 || pBt->incrVacuum==0 );
+  put4byte(&data[36 + 4*4], pBt->autoVacuum);
+  put4byte(&data[36 + 7*4], pBt->incrVacuum);
+#endif
+  pBt->nPage = 1;
+  data[31] = 1;
+  return SQLITE_OK;
+}
+
+/*
+** Initialize the first page of the database file (creating a database
+** consisting of a single page and no schema objects). Return SQLITE_OK
+** if successful, or an SQLite error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3BtreeNewDb(Btree *p){
+  int rc;
+  sqlite3BtreeEnter(p);
+  p->pBt->nPage = 0;
+  rc = newDatabase(p->pBt);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Attempt to start a new transaction. A write-transaction
+** is started if the second argument is nonzero, otherwise a read-
+** transaction.  If the second argument is 2 or more and exclusive
+** transaction is started, meaning that no other process is allowed
+** to access the database.  A preexisting transaction may not be
+** upgraded to exclusive by calling this routine a second time - the
+** exclusivity flag only works for a new transaction.
+**
+** A write-transaction must be started before attempting any
+** changes to the database.  None of the following routines
+** will work unless a transaction is started first:
+**
+**      sqlite3BtreeCreateTable()
+**      sqlite3BtreeCreateIndex()
+**      sqlite3BtreeClearTable()
+**      sqlite3BtreeDropTable()
+**      sqlite3BtreeInsert()
+**      sqlite3BtreeDelete()
+**      sqlite3BtreeUpdateMeta()
+**
+** If an initial attempt to acquire the lock fails because of lock contention
+** and the database was previously unlocked, then invoke the busy handler
+** if there is one.  But if there was previously a read-lock, do not
+** invoke the busy handler - just return SQLITE_BUSY.  SQLITE_BUSY is
+** returned when there is already a read-lock in order to avoid a deadlock.
+**
+** Suppose there are two processes A and B.  A has a read lock and B has
+** a reserved lock.  B tries to promote to exclusive but is blocked because
+** of A's read lock.  A tries to promote to reserved but is blocked by B.
+** One or the other of the two processes must give way or there can be
+** no progress.  By returning SQLITE_BUSY and not invoking the busy callback
+** when A already has a read lock, we encourage A to give up and let B
+** proceed.
+*/
+static SQLITE_NOINLINE int btreeBeginTrans(
+  Btree *p,                 /* The btree in which to start the transaction */
+  int wrflag,               /* True to start a write transaction */
+  int *pSchemaVersion       /* Put schema version number here, if not NULL */
+){
+  BtShared *pBt = p->pBt;
+  Pager *pPager = pBt->pPager;
+  int rc = SQLITE_OK;
+
+  sqlite3BtreeEnter(p);
+  btreeIntegrity(p);
+
+  /* If the btree is already in a write-transaction, or it
+  ** is already in a read-transaction and a read-transaction
+  ** is requested, this is a no-op.
+  */
+  if( p->inTrans==TRANS_WRITE || (p->inTrans==TRANS_READ && !wrflag) ){
+    goto trans_begun;
+  }
+  assert( pBt->inTransaction==TRANS_WRITE || IfNotOmitAV(pBt->bDoTruncate)==0 );
+
+  if( (p->db->flags & SQLITE_ResetDatabase)
+   && sqlite3PagerIsreadonly(pPager)==0
+  ){
+    pBt->btsFlags &= ~BTS_READ_ONLY;
+  }
+
+  /* Write transactions are not possible on a read-only database */
+  if( (pBt->btsFlags & BTS_READ_ONLY)!=0 && wrflag ){
+    rc = SQLITE_READONLY;
+    goto trans_begun;
+  }
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  {
+    sqlite3 *pBlock = 0;
+    /* If another database handle has already opened a write transaction
+    ** on this shared-btree structure and a second write transaction is
+    ** requested, return SQLITE_LOCKED.
+    */
+    if( (wrflag && pBt->inTransaction==TRANS_WRITE)
+     || (pBt->btsFlags & BTS_PENDING)!=0
+    ){
+      pBlock = pBt->pWriter->db;
+    }else if( wrflag>1 ){
+      BtLock *pIter;
+      for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+        if( pIter->pBtree!=p ){
+          pBlock = pIter->pBtree->db;
+          break;
+        }
+      }
+    }
+    if( pBlock ){
+      sqlite3ConnectionBlocked(p->db, pBlock);
+      rc = SQLITE_LOCKED_SHAREDCACHE;
+      goto trans_begun;
+    }
+  }
+#endif
+
+  /* Any read-only or read-write transaction implies a read-lock on
+  ** page 1. So if some other shared-cache client already has a write-lock
+  ** on page 1, the transaction cannot be opened. */
+  rc = querySharedCacheTableLock(p, SCHEMA_ROOT, READ_LOCK);
+  if( SQLITE_OK!=rc ) goto trans_begun;
+
+  pBt->btsFlags &= ~BTS_INITIALLY_EMPTY;
+  if( pBt->nPage==0 ) pBt->btsFlags |= BTS_INITIALLY_EMPTY;
+  do {
+    sqlite3PagerWalDb(pPager, p->db);
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    /* If transitioning from no transaction directly to a write transaction,
+    ** block for the WRITER lock first if possible. */
+    if( pBt->pPage1==0 && wrflag ){
+      assert( pBt->inTransaction==TRANS_NONE );
+      rc = sqlite3PagerWalWriteLock(pPager, 1);
+      if( rc!=SQLITE_BUSY && rc!=SQLITE_OK ) break;
+    }
+#endif
+
+    /* Call lockBtree() until either pBt->pPage1 is populated or
+    ** lockBtree() returns something other than SQLITE_OK. lockBtree()
+    ** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
+    ** reading page 1 it discovers that the page-size of the database
+    ** file is not pBt->pageSize. In this case lockBtree() will update
+    ** pBt->pageSize to the page-size of the file on disk.
+    */
+    while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );
+
+    if( rc==SQLITE_OK && wrflag ){
+      if( (pBt->btsFlags & BTS_READ_ONLY)!=0 ){
+        rc = SQLITE_READONLY;
+      }else{
+        rc = sqlite3PagerBegin(pPager, wrflag>1, sqlite3TempInMemory(p->db));
+        if( rc==SQLITE_OK ){
+          rc = newDatabase(pBt);
+        }else if( rc==SQLITE_BUSY_SNAPSHOT && pBt->inTransaction==TRANS_NONE ){
+          /* if there was no transaction opened when this function was
+          ** called and SQLITE_BUSY_SNAPSHOT is returned, change the error
+          ** code to SQLITE_BUSY. */
+          rc = SQLITE_BUSY;
+        }
+      }
+    }
+
+    if( rc!=SQLITE_OK ){
+      (void)sqlite3PagerWalWriteLock(pPager, 0);
+      unlockBtreeIfUnused(pBt);
+    }
+  }while( (rc&0xFF)==SQLITE_BUSY && pBt->inTransaction==TRANS_NONE &&
+          btreeInvokeBusyHandler(pBt) );
+  sqlite3PagerWalDb(pPager, 0);
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  if( rc==SQLITE_BUSY_TIMEOUT ) rc = SQLITE_BUSY;
+#endif
+
+  if( rc==SQLITE_OK ){
+    if( p->inTrans==TRANS_NONE ){
+      pBt->nTransaction++;
+#ifndef SQLITE_OMIT_SHARED_CACHE
+      if( p->sharable ){
+        assert( p->lock.pBtree==p && p->lock.iTable==1 );
+        p->lock.eLock = READ_LOCK;
+        p->lock.pNext = pBt->pLock;
+        pBt->pLock = &p->lock;
+      }
+#endif
+    }
+    p->inTrans = (wrflag?TRANS_WRITE:TRANS_READ);
+    if( p->inTrans>pBt->inTransaction ){
+      pBt->inTransaction = p->inTrans;
+    }
+    if( wrflag ){
+      MemPage *pPage1 = pBt->pPage1;
+#ifndef SQLITE_OMIT_SHARED_CACHE
+      assert( !pBt->pWriter );
+      pBt->pWriter = p;
+      pBt->btsFlags &= ~BTS_EXCLUSIVE;
+      if( wrflag>1 ) pBt->btsFlags |= BTS_EXCLUSIVE;
+#endif
+
+      /* If the db-size header field is incorrect (as it may be if an old
+      ** client has been writing the database file), update it now. Doing
+      ** this sooner rather than later means the database size can safely
+      ** re-read the database size from page 1 if a savepoint or transaction
+      ** rollback occurs within the transaction.
+      */
+      if( pBt->nPage!=get4byte(&pPage1->aData[28]) ){
+        rc = sqlite3PagerWrite(pPage1->pDbPage);
+        if( rc==SQLITE_OK ){
+          put4byte(&pPage1->aData[28], pBt->nPage);
+        }
+      }
+    }
+  }
+
+trans_begun:
+  if( rc==SQLITE_OK ){
+    if( pSchemaVersion ){
+      *pSchemaVersion = get4byte(&pBt->pPage1->aData[40]);
+    }
+    if( wrflag ){
+      /* This call makes sure that the pager has the correct number of
+      ** open savepoints. If the second parameter is greater than 0 and
+      ** the sub-journal is not already open, then it will be opened here.
+      */
+      rc = sqlite3PagerOpenSavepoint(pPager, p->db->nSavepoint);
+    }
+  }
+
+  btreeIntegrity(p);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag, int *pSchemaVersion){
+  BtShared *pBt;
+  if( p->sharable
+   || p->inTrans==TRANS_NONE
+   || (p->inTrans==TRANS_READ && wrflag!=0)
+  ){
+    return btreeBeginTrans(p,wrflag,pSchemaVersion);
+  }
+  pBt = p->pBt;
+  if( pSchemaVersion ){
+    *pSchemaVersion = get4byte(&pBt->pPage1->aData[40]);
+  }
+  if( wrflag ){
+    /* This call makes sure that the pager has the correct number of
+    ** open savepoints. If the second parameter is greater than 0 and
+    ** the sub-journal is not already open, then it will be opened here.
+    */
+    return sqlite3PagerOpenSavepoint(pBt->pPager, p->db->nSavepoint);
+  }else{
+    return SQLITE_OK;
+  }
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+
+/*
+** Set the pointer-map entries for all children of page pPage. Also, if
+** pPage contains cells that point to overflow pages, set the pointer
+** map entries for the overflow pages as well.
+*/
+static int setChildPtrmaps(MemPage *pPage){
+  int i;                             /* Counter variable */
+  int nCell;                         /* Number of cells in page pPage */
+  int rc;                            /* Return code */
+  BtShared *pBt = pPage->pBt;
+  Pgno pgno = pPage->pgno;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  rc = pPage->isInit ? SQLITE_OK : btreeInitPage(pPage);
+  if( rc!=SQLITE_OK ) return rc;
+  nCell = pPage->nCell;
+
+  for(i=0; i<nCell; i++){
+    u8 *pCell = findCell(pPage, i);
+
+    ptrmapPutOvflPtr(pPage, pPage, pCell, &rc);
+
+    if( !pPage->leaf ){
+      Pgno childPgno = get4byte(pCell);
+      ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno, &rc);
+    }
+  }
+
+  if( !pPage->leaf ){
+    Pgno childPgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno, &rc);
+  }
+
+  return rc;
+}
+
+/*
+** Somewhere on pPage is a pointer to page iFrom.  Modify this pointer so
+** that it points to iTo. Parameter eType describes the type of pointer to
+** be modified, as  follows:
+**
+** PTRMAP_BTREE:     pPage is a btree-page. The pointer points at a child
+**                   page of pPage.
+**
+** PTRMAP_OVERFLOW1: pPage is a btree-page. The pointer points at an overflow
+**                   page pointed to by one of the cells on pPage.
+**
+** PTRMAP_OVERFLOW2: pPage is an overflow-page. The pointer points at the next
+**                   overflow page in the list.
+*/
+static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  if( eType==PTRMAP_OVERFLOW2 ){
+    /* The pointer is always the first 4 bytes of the page in this case.  */
+    if( get4byte(pPage->aData)!=iFrom ){
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    put4byte(pPage->aData, iTo);
+  }else{
+    int i;
+    int nCell;
+    int rc;
+
+    rc = pPage->isInit ? SQLITE_OK : btreeInitPage(pPage);
+    if( rc ) return rc;
+    nCell = pPage->nCell;
+
+    for(i=0; i<nCell; i++){
+      u8 *pCell = findCell(pPage, i);
+      if( eType==PTRMAP_OVERFLOW1 ){
+        CellInfo info;
+        pPage->xParseCell(pPage, pCell, &info);
+        if( info.nLocal<info.nPayload ){
+          if( pCell+info.nSize > pPage->aData+pPage->pBt->usableSize ){
+            return SQLITE_CORRUPT_PAGE(pPage);
+          }
+          if( iFrom==get4byte(pCell+info.nSize-4) ){
+            put4byte(pCell+info.nSize-4, iTo);
+            break;
+          }
+        }
+      }else{
+        if( pCell+4 > pPage->aData+pPage->pBt->usableSize ){
+          return SQLITE_CORRUPT_PAGE(pPage);
+        }
+        if( get4byte(pCell)==iFrom ){
+          put4byte(pCell, iTo);
+          break;
+        }
+      }
+    }
+
+    if( i==nCell ){
+      if( eType!=PTRMAP_BTREE ||
+          get4byte(&pPage->aData[pPage->hdrOffset+8])!=iFrom ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      put4byte(&pPage->aData[pPage->hdrOffset+8], iTo);
+    }
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** Move the open database page pDbPage to location iFreePage in the
+** database. The pDbPage reference remains valid.
+**
+** The isCommit flag indicates that there is no need to remember that
+** the journal needs to be sync()ed before database page pDbPage->pgno
+** can be written to. The caller has already promised not to write to that
+** page.
+*/
+static int relocatePage(
+  BtShared *pBt,           /* Btree */
+  MemPage *pDbPage,        /* Open page to move */
+  u8 eType,                /* Pointer map 'type' entry for pDbPage */
+  Pgno iPtrPage,           /* Pointer map 'page-no' entry for pDbPage */
+  Pgno iFreePage,          /* The location to move pDbPage to */
+  int isCommit             /* isCommit flag passed to sqlite3PagerMovepage */
+){
+  MemPage *pPtrPage;   /* The page that contains a pointer to pDbPage */
+  Pgno iDbPage = pDbPage->pgno;
+  Pager *pPager = pBt->pPager;
+  int rc;
+
+  assert( eType==PTRMAP_OVERFLOW2 || eType==PTRMAP_OVERFLOW1 ||
+      eType==PTRMAP_BTREE || eType==PTRMAP_ROOTPAGE );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pDbPage->pBt==pBt );
+  if( iDbPage<3 ) return SQLITE_CORRUPT_BKPT;
+
+  /* Move page iDbPage from its current location to page number iFreePage */
+  TRACE(("AUTOVACUUM: Moving %u to free page %u (ptr page %u type %u)\n",
+      iDbPage, iFreePage, iPtrPage, eType));
+  rc = sqlite3PagerMovepage(pPager, pDbPage->pDbPage, iFreePage, isCommit);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  pDbPage->pgno = iFreePage;
+
+  /* If pDbPage was a btree-page, then it may have child pages and/or cells
+  ** that point to overflow pages. The pointer map entries for all these
+  ** pages need to be changed.
+  **
+  ** If pDbPage is an overflow page, then the first 4 bytes may store a
+  ** pointer to a subsequent overflow page. If this is the case, then
+  ** the pointer map needs to be updated for the subsequent overflow page.
+  */
+  if( eType==PTRMAP_BTREE || eType==PTRMAP_ROOTPAGE ){
+    rc = setChildPtrmaps(pDbPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+  }else{
+    Pgno nextOvfl = get4byte(pDbPage->aData);
+    if( nextOvfl!=0 ){
+      ptrmapPut(pBt, nextOvfl, PTRMAP_OVERFLOW2, iFreePage, &rc);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }
+  }
+
+  /* Fix the database pointer on page iPtrPage that pointed at iDbPage so
+  ** that it points at iFreePage. Also fix the pointer map entry for
+  ** iPtrPage.
+  */
+  if( eType!=PTRMAP_ROOTPAGE ){
+    rc = btreeGetPage(pBt, iPtrPage, &pPtrPage, 0);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    rc = sqlite3PagerWrite(pPtrPage->pDbPage);
+    if( rc!=SQLITE_OK ){
+      releasePage(pPtrPage);
+      return rc;
+    }
+    rc = modifyPagePointer(pPtrPage, iDbPage, iFreePage, eType);
+    releasePage(pPtrPage);
+    if( rc==SQLITE_OK ){
+      ptrmapPut(pBt, iFreePage, eType, iPtrPage, &rc);
+    }
+  }
+  return rc;
+}
+
+/* Forward declaration required by incrVacuumStep(). */
+static int allocateBtreePage(BtShared *, MemPage **, Pgno *, Pgno, u8);
+
+/*
+** Perform a single step of an incremental-vacuum. If successful, return
+** SQLITE_OK. If there is no work to do (and therefore no point in
+** calling this function again), return SQLITE_DONE. Or, if an error
+** occurs, return some other error code.
+**
+** More specifically, this function attempts to re-organize the database so
+** that the last page of the file currently in use is no longer in use.
+**
+** Parameter nFin is the number of pages that this database would contain
+** were this function called until it returns SQLITE_DONE.
+**
+** If the bCommit parameter is non-zero, this function assumes that the
+** caller will keep calling incrVacuumStep() until it returns SQLITE_DONE
+** or an error. bCommit is passed true for an auto-vacuum-on-commit
+** operation, or false for an incremental vacuum.
+*/
+static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg, int bCommit){
+  Pgno nFreeList;           /* Number of pages still on the free-list */
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( iLastPg>nFin );
+
+  if( !PTRMAP_ISPAGE(pBt, iLastPg) && iLastPg!=PENDING_BYTE_PAGE(pBt) ){
+    u8 eType;
+    Pgno iPtrPage;
+
+    nFreeList = get4byte(&pBt->pPage1->aData[36]);
+    if( nFreeList==0 ){
+      return SQLITE_DONE;
+    }
+
+    rc = ptrmapGet(pBt, iLastPg, &eType, &iPtrPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( eType==PTRMAP_ROOTPAGE ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+
+    if( eType==PTRMAP_FREEPAGE ){
+      if( bCommit==0 ){
+        /* Remove the page from the files free-list. This is not required
+        ** if bCommit is non-zero. In that case, the free-list will be
+        ** truncated to zero after this function returns, so it doesn't
+        ** matter if it still contains some garbage entries.
+        */
+        Pgno iFreePg;
+        MemPage *pFreePg;
+        rc = allocateBtreePage(pBt, &pFreePg, &iFreePg, iLastPg, BTALLOC_EXACT);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        assert( iFreePg==iLastPg );
+        releasePage(pFreePg);
+      }
+    } else {
+      Pgno iFreePg;             /* Index of free page to move pLastPg to */
+      MemPage *pLastPg;
+      u8 eMode = BTALLOC_ANY;   /* Mode parameter for allocateBtreePage() */
+      Pgno iNear = 0;           /* nearby parameter for allocateBtreePage() */
+
+      rc = btreeGetPage(pBt, iLastPg, &pLastPg, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+
+      /* If bCommit is zero, this loop runs exactly once and page pLastPg
+      ** is swapped with the first free page pulled off the free list.
+      **
+      ** On the other hand, if bCommit is greater than zero, then keep
+      ** looping until a free-page located within the first nFin pages
+      ** of the file is found.
+      */
+      if( bCommit==0 ){
+        eMode = BTALLOC_LE;
+        iNear = nFin;
+      }
+      do {
+        MemPage *pFreePg;
+        Pgno dbSize = btreePagecount(pBt);
+        rc = allocateBtreePage(pBt, &pFreePg, &iFreePg, iNear, eMode);
+        if( rc!=SQLITE_OK ){
+          releasePage(pLastPg);
+          return rc;
+        }
+        releasePage(pFreePg);
+        if( iFreePg>dbSize ){
+          releasePage(pLastPg);
+          return SQLITE_CORRUPT_BKPT;
+        }
+      }while( bCommit && iFreePg>nFin );
+      assert( iFreePg<iLastPg );
+
+      rc = relocatePage(pBt, pLastPg, eType, iPtrPage, iFreePg, bCommit);
+      releasePage(pLastPg);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }
+  }
+
+  if( bCommit==0 ){
+    do {
+      iLastPg--;
+    }while( iLastPg==PENDING_BYTE_PAGE(pBt) || PTRMAP_ISPAGE(pBt, iLastPg) );
+    pBt->bDoTruncate = 1;
+    pBt->nPage = iLastPg;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The database opened by the first argument is an auto-vacuum database
+** nOrig pages in size containing nFree free pages. Return the expected
+** size of the database in pages following an auto-vacuum operation.
+*/
+static Pgno finalDbSize(BtShared *pBt, Pgno nOrig, Pgno nFree){
+  int nEntry;                     /* Number of entries on one ptrmap page */
+  Pgno nPtrmap;                   /* Number of PtrMap pages to be freed */
+  Pgno nFin;                      /* Return value */
+
+  nEntry = pBt->usableSize/5;
+  nPtrmap = (nFree-nOrig+PTRMAP_PAGENO(pBt, nOrig)+nEntry)/nEntry;
+  nFin = nOrig - nFree - nPtrmap;
+  if( nOrig>PENDING_BYTE_PAGE(pBt) && nFin<PENDING_BYTE_PAGE(pBt) ){
+    nFin--;
+  }
+  while( PTRMAP_ISPAGE(pBt, nFin) || nFin==PENDING_BYTE_PAGE(pBt) ){
+    nFin--;
+  }
+
+  return nFin;
+}
+
+/*
+** A write-transaction must be opened before calling this function.
+** It performs a single unit of work towards an incremental vacuum.
+**
+** If the incremental vacuum is finished after this function has run,
+** SQLITE_DONE is returned. If it is not finished, but no error occurred,
+** SQLITE_OK is returned. Otherwise an SQLite error code.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *p){
+  int rc;
+  BtShared *pBt = p->pBt;
+
+  sqlite3BtreeEnter(p);
+  assert( pBt->inTransaction==TRANS_WRITE && p->inTrans==TRANS_WRITE );
+  if( !pBt->autoVacuum ){
+    rc = SQLITE_DONE;
+  }else{
+    Pgno nOrig = btreePagecount(pBt);
+    Pgno nFree = get4byte(&pBt->pPage1->aData[36]);
+    Pgno nFin = finalDbSize(pBt, nOrig, nFree);
+
+    if( nOrig<nFin || nFree>=nOrig ){
+      rc = SQLITE_CORRUPT_BKPT;
+    }else if( nFree>0 ){
+      rc = saveAllCursors(pBt, 0, 0);
+      if( rc==SQLITE_OK ){
+        invalidateAllOverflowCache(pBt);
+        rc = incrVacuumStep(pBt, nFin, nOrig, 0);
+      }
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+        put4byte(&pBt->pPage1->aData[28], pBt->nPage);
+      }
+    }else{
+      rc = SQLITE_DONE;
+    }
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** This routine is called prior to sqlite3PagerCommit when a transaction
+** is committed for an auto-vacuum database.
+*/
+static int autoVacuumCommit(Btree *p){
+  int rc = SQLITE_OK;
+  Pager *pPager;
+  BtShared *pBt;
+  sqlite3 *db;
+  VVA_ONLY( int nRef );
+
+  assert( p!=0 );
+  pBt = p->pBt;
+  pPager = pBt->pPager;
+  VVA_ONLY( nRef = sqlite3PagerRefcount(pPager); )
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  invalidateAllOverflowCache(pBt);
+  assert(pBt->autoVacuum);
+  if( !pBt->incrVacuum ){
+    Pgno nFin;         /* Number of pages in database after autovacuuming */
+    Pgno nFree;        /* Number of pages on the freelist initially */
+    Pgno nVac;         /* Number of pages to vacuum */
+    Pgno iFree;        /* The next page to be freed */
+    Pgno nOrig;        /* Database size before freeing */
+
+    nOrig = btreePagecount(pBt);
+    if( PTRMAP_ISPAGE(pBt, nOrig) || nOrig==PENDING_BYTE_PAGE(pBt) ){
+      /* It is not possible to create a database for which the final page
+      ** is either a pointer-map page or the pending-byte page. If one
+      ** is encountered, this indicates corruption.
+      */
+      return SQLITE_CORRUPT_BKPT;
+    }
+
+    nFree = get4byte(&pBt->pPage1->aData[36]);
+    db = p->db;
+    if( db->xAutovacPages ){
+      int iDb;
+      for(iDb=0; ALWAYS(iDb<db->nDb); iDb++){
+        if( db->aDb[iDb].pBt==p ) break;
+      }
+      nVac = db->xAutovacPages(
+        db->pAutovacPagesArg,
+        db->aDb[iDb].zDbSName,
+        nOrig,
+        nFree,
+        pBt->pageSize
+      );
+      if( nVac>nFree ){
+        nVac = nFree;
+      }
+      if( nVac==0 ){
+        return SQLITE_OK;
+      }
+    }else{
+      nVac = nFree;
+    }
+    nFin = finalDbSize(pBt, nOrig, nVac);
+    if( nFin>nOrig ) return SQLITE_CORRUPT_BKPT;
+    if( nFin<nOrig ){
+      rc = saveAllCursors(pBt, 0, 0);
+    }
+    for(iFree=nOrig; iFree>nFin && rc==SQLITE_OK; iFree--){
+      rc = incrVacuumStep(pBt, nFin, iFree, nVac==nFree);
+    }
+    if( (rc==SQLITE_DONE || rc==SQLITE_OK) && nFree>0 ){
+      rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+      if( nVac==nFree ){
+        put4byte(&pBt->pPage1->aData[32], 0);
+        put4byte(&pBt->pPage1->aData[36], 0);
+      }
+      put4byte(&pBt->pPage1->aData[28], nFin);
+      pBt->bDoTruncate = 1;
+      pBt->nPage = nFin;
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3PagerRollback(pPager);
+    }
+  }
+
+  assert( nRef>=sqlite3PagerRefcount(pPager) );
+  return rc;
+}
+
+#else /* ifndef SQLITE_OMIT_AUTOVACUUM */
+# define setChildPtrmaps(x) SQLITE_OK
+#endif
+
+/*
+** This routine does the first phase of a two-phase commit.  This routine
+** causes a rollback journal to be created (if it does not already exist)
+** and populated with enough information so that if a power loss occurs
+** the database can be restored to its original state by playing back
+** the journal.  Then the contents of the journal are flushed out to
+** the disk.  After the journal is safely on oxide, the changes to the
+** database are written into the database file and flushed to oxide.
+** At the end of this call, the rollback journal still exists on the
+** disk and we are still holding all locks, so the transaction has not
+** committed.  See sqlite3BtreeCommitPhaseTwo() for the second phase of the
+** commit process.
+**
+** This call is a no-op if no write-transaction is currently active on pBt.
+**
+** Otherwise, sync the database file for the btree pBt. zSuperJrnl points to
+** the name of a super-journal file that should be written into the
+** individual journal file, or is NULL, indicating no super-journal file
+** (single database transaction).
+**
+** When this is called, the super-journal should already have been
+** created, populated with this journal pointer and synced to disk.
+**
+** Once this is routine has returned, the only thing required to commit
+** the write-transaction for this database file is to delete the journal.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree *p, const char *zSuperJrnl){
+  int rc = SQLITE_OK;
+  if( p->inTrans==TRANS_WRITE ){
+    BtShared *pBt = p->pBt;
+    sqlite3BtreeEnter(p);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum ){
+      rc = autoVacuumCommit(p);
+      if( rc!=SQLITE_OK ){
+        sqlite3BtreeLeave(p);
+        return rc;
+      }
+    }
+    if( pBt->bDoTruncate ){
+      sqlite3PagerTruncateImage(pBt->pPager, pBt->nPage);
+    }
+#endif
+    rc = sqlite3PagerCommitPhaseOne(pBt->pPager, zSuperJrnl, 0);
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+
+/*
+** This function is called from both BtreeCommitPhaseTwo() and BtreeRollback()
+** at the conclusion of a transaction.
+*/
+static void btreeEndTransaction(Btree *p){
+  BtShared *pBt = p->pBt;
+  sqlite3 *db = p->db;
+  assert( sqlite3BtreeHoldsMutex(p) );
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  pBt->bDoTruncate = 0;
+#endif
+  if( p->inTrans>TRANS_NONE && db->nVdbeRead>1 ){
+    /* If there are other active statements that belong to this database
+    ** handle, downgrade to a read-only transaction. The other statements
+    ** may still be reading from the database.  */
+    downgradeAllSharedCacheTableLocks(p);
+    p->inTrans = TRANS_READ;
+  }else{
+    /* If the handle had any kind of transaction open, decrement the
+    ** transaction count of the shared btree. If the transaction count
+    ** reaches 0, set the shared state to TRANS_NONE. The unlockBtreeIfUnused()
+    ** call below will unlock the pager.  */
+    if( p->inTrans!=TRANS_NONE ){
+      clearAllSharedCacheTableLocks(p);
+      pBt->nTransaction--;
+      if( 0==pBt->nTransaction ){
+        pBt->inTransaction = TRANS_NONE;
+      }
+    }
+
+    /* Set the current transaction state to TRANS_NONE and unlock the
+    ** pager if this call closed the only read or write transaction.  */
+    p->inTrans = TRANS_NONE;
+    unlockBtreeIfUnused(pBt);
+  }
+
+  btreeIntegrity(p);
+}
+
+/*
+** Commit the transaction currently in progress.
+**
+** This routine implements the second phase of a 2-phase commit.  The
+** sqlite3BtreeCommitPhaseOne() routine does the first phase and should
+** be invoked prior to calling this routine.  The sqlite3BtreeCommitPhaseOne()
+** routine did all the work of writing information out to disk and flushing the
+** contents so that they are written onto the disk platter.  All this
+** routine has to do is delete or truncate or zero the header in the
+** the rollback journal (which causes the transaction to commit) and
+** drop locks.
+**
+** Normally, if an error occurs while the pager layer is attempting to
+** finalize the underlying journal file, this function returns an error and
+** the upper layer will attempt a rollback. However, if the second argument
+** is non-zero then this b-tree transaction is part of a multi-file
+** transaction. In this case, the transaction has already been committed
+** (by deleting a super-journal file) and the caller will ignore this
+** functions return code. So, even if an error occurs in the pager layer,
+** reset the b-tree objects internal state to indicate that the write
+** transaction has been closed. This is quite safe, as the pager will have
+** transitioned to the error state.
+**
+** This will release the write lock on the database file.  If there
+** are no active cursors, it also releases the read lock.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree *p, int bCleanup){
+
+  if( p->inTrans==TRANS_NONE ) return SQLITE_OK;
+  sqlite3BtreeEnter(p);
+  btreeIntegrity(p);
+
+  /* If the handle has a write-transaction open, commit the shared-btrees
+  ** transaction and set the shared state to TRANS_READ.
+  */
+  if( p->inTrans==TRANS_WRITE ){
+    int rc;
+    BtShared *pBt = p->pBt;
+    assert( pBt->inTransaction==TRANS_WRITE );
+    assert( pBt->nTransaction>0 );
+    rc = sqlite3PagerCommitPhaseTwo(pBt->pPager);
+    if( rc!=SQLITE_OK && bCleanup==0 ){
+      sqlite3BtreeLeave(p);
+      return rc;
+    }
+    p->iBDataVersion--;  /* Compensate for pPager->iDataVersion++; */
+    pBt->inTransaction = TRANS_READ;
+    btreeClearHasContent(pBt);
+  }
+
+  btreeEndTransaction(p);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Do both phases of a commit.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommit(Btree *p){
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = sqlite3BtreeCommitPhaseOne(p, 0);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3BtreeCommitPhaseTwo(p, 0);
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** This routine sets the state to CURSOR_FAULT and the error
+** code to errCode for every cursor on any BtShared that pBtree
+** references.  Or if the writeOnly flag is set to 1, then only
+** trip write cursors and leave read cursors unchanged.
+**
+** Every cursor is a candidate to be tripped, including cursors
+** that belong to other database connections that happen to be
+** sharing the cache with pBtree.
+**
+** This routine gets called when a rollback occurs. If the writeOnly
+** flag is true, then only write-cursors need be tripped - read-only
+** cursors save their current positions so that they may continue
+** following the rollback. Or, if writeOnly is false, all cursors are
+** tripped. In general, writeOnly is false if the transaction being
+** rolled back modified the database schema. In this case b-tree root
+** pages may be moved or deleted from the database altogether, making
+** it unsafe for read cursors to continue.
+**
+** If the writeOnly flag is true and an error is encountered while
+** saving the current position of a read-only cursor, all cursors,
+** including all read-cursors are tripped.
+**
+** SQLITE_OK is returned if successful, or if an error occurs while
+** saving a cursor position, an SQLite error code.
+*/
+SQLITE_PRIVATE int sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode, int writeOnly){
+  BtCursor *p;
+  int rc = SQLITE_OK;
+
+  assert( (writeOnly==0 || writeOnly==1) && BTCF_WriteFlag==1 );
+  if( pBtree ){
+    sqlite3BtreeEnter(pBtree);
+    for(p=pBtree->pBt->pCursor; p; p=p->pNext){
+      if( writeOnly && (p->curFlags & BTCF_WriteFlag)==0 ){
+        if( p->eState==CURSOR_VALID || p->eState==CURSOR_SKIPNEXT ){
+          rc = saveCursorPosition(p);
+          if( rc!=SQLITE_OK ){
+            (void)sqlite3BtreeTripAllCursors(pBtree, rc, 0);
+            break;
+          }
+        }
+      }else{
+        sqlite3BtreeClearCursor(p);
+        p->eState = CURSOR_FAULT;
+        p->skipNext = errCode;
+      }
+      btreeReleaseAllCursorPages(p);
+    }
+    sqlite3BtreeLeave(pBtree);
+  }
+  return rc;
+}
+
+/*
+** Set the pBt->nPage field correctly, according to the current
+** state of the database.  Assume pBt->pPage1 is valid.
+*/
+static void btreeSetNPage(BtShared *pBt, MemPage *pPage1){
+  int nPage = get4byte(&pPage1->aData[28]);
+  testcase( nPage==0 );
+  if( nPage==0 ) sqlite3PagerPagecount(pBt->pPager, &nPage);
+  testcase( pBt->nPage!=(u32)nPage );
+  pBt->nPage = nPage;
+}
+
+/*
+** Rollback the transaction in progress.
+**
+** If tripCode is not SQLITE_OK then cursors will be invalidated (tripped).
+** Only write cursors are tripped if writeOnly is true but all cursors are
+** tripped if writeOnly is false.  Any attempt to use
+** a tripped cursor will result in an error.
+**
+** This will release the write lock on the database file.  If there
+** are no active cursors, it also releases the read lock.
+*/
+SQLITE_PRIVATE int sqlite3BtreeRollback(Btree *p, int tripCode, int writeOnly){
+  int rc;
+  BtShared *pBt = p->pBt;
+  MemPage *pPage1;
+
+  assert( writeOnly==1 || writeOnly==0 );
+  assert( tripCode==SQLITE_ABORT_ROLLBACK || tripCode==SQLITE_OK );
+  sqlite3BtreeEnter(p);
+  if( tripCode==SQLITE_OK ){
+    rc = tripCode = saveAllCursors(pBt, 0, 0);
+    if( rc ) writeOnly = 0;
+  }else{
+    rc = SQLITE_OK;
+  }
+  if( tripCode ){
+    int rc2 = sqlite3BtreeTripAllCursors(p, tripCode, writeOnly);
+    assert( rc==SQLITE_OK || (writeOnly==0 && rc2==SQLITE_OK) );
+    if( rc2!=SQLITE_OK ) rc = rc2;
+  }
+  btreeIntegrity(p);
+
+  if( p->inTrans==TRANS_WRITE ){
+    int rc2;
+
+    assert( TRANS_WRITE==pBt->inTransaction );
+    rc2 = sqlite3PagerRollback(pBt->pPager);
+    if( rc2!=SQLITE_OK ){
+      rc = rc2;
+    }
+
+    /* The rollback may have destroyed the pPage1->aData value.  So
+    ** call btreeGetPage() on page 1 again to make
+    ** sure pPage1->aData is set correctly. */
+    if( btreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){
+      btreeSetNPage(pBt, pPage1);
+      releasePageOne(pPage1);
+    }
+    assert( countValidCursors(pBt, 1)==0 );
+    pBt->inTransaction = TRANS_READ;
+    btreeClearHasContent(pBt);
+  }
+
+  btreeEndTransaction(p);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Start a statement subtransaction. The subtransaction can be rolled
+** back independently of the main transaction. You must start a transaction
+** before starting a subtransaction. The subtransaction is ended automatically
+** if the main transaction commits or rolls back.
+**
+** Statement subtransactions are used around individual SQL statements
+** that are contained within a BEGIN...COMMIT block.  If a constraint
+** error occurs within the statement, the effect of that one statement
+** can be rolled back without having to rollback the entire transaction.
+**
+** A statement sub-transaction is implemented as an anonymous savepoint. The
+** value passed as the second parameter is the total number of savepoints,
+** including the new anonymous savepoint, open on the B-Tree. i.e. if there
+** are no active savepoints and no other statement-transactions open,
+** iStatement is 1. This anonymous savepoint can be released or rolled back
+** using the sqlite3BtreeSavepoint() function.
+*/
+SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree *p, int iStatement){
+  int rc;
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans==TRANS_WRITE );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
+  assert( iStatement>0 );
+  assert( iStatement>p->db->nSavepoint );
+  assert( pBt->inTransaction==TRANS_WRITE );
+  /* At the pager level, a statement transaction is a savepoint with
+  ** an index greater than all savepoints created explicitly using
+  ** SQL statements. It is illegal to open, release or rollback any
+  ** such savepoints while the statement transaction savepoint is active.
+  */
+  rc = sqlite3PagerOpenSavepoint(pBt->pPager, iStatement);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** The second argument to this function, op, is always SAVEPOINT_ROLLBACK
+** or SAVEPOINT_RELEASE. This function either releases or rolls back the
+** savepoint identified by parameter iSavepoint, depending on the value
+** of op.
+**
+** Normally, iSavepoint is greater than or equal to zero. However, if op is
+** SAVEPOINT_ROLLBACK, then iSavepoint may also be -1. In this case the
+** contents of the entire transaction are rolled back. This is different
+** from a normal transaction rollback, as no locks are released and the
+** transaction remains open.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
+  int rc = SQLITE_OK;
+  if( p && p->inTrans==TRANS_WRITE ){
+    BtShared *pBt = p->pBt;
+    assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
+    assert( iSavepoint>=0 || (iSavepoint==-1 && op==SAVEPOINT_ROLLBACK) );
+    sqlite3BtreeEnter(p);
+    if( op==SAVEPOINT_ROLLBACK ){
+      rc = saveAllCursors(pBt, 0, 0);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3PagerSavepoint(pBt->pPager, op, iSavepoint);
+    }
+    if( rc==SQLITE_OK ){
+      if( iSavepoint<0 && (pBt->btsFlags & BTS_INITIALLY_EMPTY)!=0 ){
+        pBt->nPage = 0;
+      }
+      rc = newDatabase(pBt);
+      btreeSetNPage(pBt, pBt->pPage1);
+
+      /* pBt->nPage might be zero if the database was corrupt when
+      ** the transaction was started. Otherwise, it must be at least 1.  */
+      assert( CORRUPT_DB || pBt->nPage>0 );
+    }
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+
+/*
+** Create a new cursor for the BTree whose root is on the page
+** iTable. If a read-only cursor is requested, it is assumed that
+** the caller already has at least a read-only transaction open
+** on the database already. If a write-cursor is requested, then
+** the caller is assumed to have an open write transaction.
+**
+** If the BTREE_WRCSR bit of wrFlag is clear, then the cursor can only
+** be used for reading.  If the BTREE_WRCSR bit is set, then the cursor
+** can be used for reading or for writing if other conditions for writing
+** are also met.  These are the conditions that must be met in order
+** for writing to be allowed:
+**
+** 1:  The cursor must have been opened with wrFlag containing BTREE_WRCSR
+**
+** 2:  Other database connections that share the same pager cache
+**     but which are not in the READ_UNCOMMITTED state may not have
+**     cursors open with wrFlag==0 on the same table.  Otherwise
+**     the changes made by this write cursor would be visible to
+**     the read cursors in the other database connection.
+**
+** 3:  The database must be writable (not on read-only media)
+**
+** 4:  There must be an active transaction.
+**
+** The BTREE_FORDELETE bit of wrFlag may optionally be set if BTREE_WRCSR
+** is set.  If FORDELETE is set, that is a hint to the implementation that
+** this cursor will only be used to seek to and delete entries of an index
+** as part of a larger DELETE statement.  The FORDELETE hint is not used by
+** this implementation.  But in a hypothetical alternative storage engine
+** in which index entries are automatically deleted when corresponding table
+** rows are deleted, the FORDELETE flag is a hint that all SEEK and DELETE
+** operations on this cursor can be no-ops and all READ operations can
+** return a null row (2-bytes: 0x01 0x00).
+**
+** No checking is done to make sure that page iTable really is the
+** root page of a b-tree.  If it is not, then the cursor acquired
+** will not work correctly.
+**
+** It is assumed that the sqlite3BtreeCursorZero() has been called
+** on pCur to initialize the memory space prior to invoking this routine.
+*/
+static int btreeCursor(
+  Btree *p,                              /* The btree */
+  Pgno iTable,                           /* Root page of table to open */
+  int wrFlag,                            /* 1 to write. 0 read-only */
+  struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
+  BtCursor *pCur                         /* Space for new cursor */
+){
+  BtShared *pBt = p->pBt;                /* Shared b-tree handle */
+  BtCursor *pX;                          /* Looping over other all cursors */
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( wrFlag==0
+       || wrFlag==BTREE_WRCSR
+       || wrFlag==(BTREE_WRCSR|BTREE_FORDELETE)
+  );
+
+  /* The following assert statements verify that if this is a sharable
+  ** b-tree database, the connection is holding the required table locks,
+  ** and that no other connection has any open cursor that conflicts with
+  ** this lock.  The iTable<1 term disables the check for corrupt schemas. */
+  assert( hasSharedCacheTableLock(p, iTable, pKeyInfo!=0, (wrFlag?2:1))
+          || iTable<1 );
+  assert( wrFlag==0 || !hasReadConflicts(p, iTable) );
+
+  /* Assert that the caller has opened the required transaction. */
+  assert( p->inTrans>TRANS_NONE );
+  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
+  assert( pBt->pPage1 && pBt->pPage1->aData );
+  assert( wrFlag==0 || (pBt->btsFlags & BTS_READ_ONLY)==0 );
+
+  if( iTable<=1 ){
+    if( iTable<1 ){
+      return SQLITE_CORRUPT_BKPT;
+    }else if( btreePagecount(pBt)==0 ){
+      assert( wrFlag==0 );
+      iTable = 0;
+    }
+  }
+
+  /* Now that no other errors can occur, finish filling in the BtCursor
+  ** variables and link the cursor into the BtShared list.  */
+  pCur->pgnoRoot = iTable;
+  pCur->iPage = -1;
+  pCur->pKeyInfo = pKeyInfo;
+  pCur->pBtree = p;
+  pCur->pBt = pBt;
+  pCur->curFlags = 0;
+  /* If there are two or more cursors on the same btree, then all such
+  ** cursors *must* have the BTCF_Multiple flag set. */
+  for(pX=pBt->pCursor; pX; pX=pX->pNext){
+    if( pX->pgnoRoot==iTable ){
+      pX->curFlags |= BTCF_Multiple;
+      pCur->curFlags = BTCF_Multiple;
+    }
+  }
+  pCur->eState = CURSOR_INVALID;
+  pCur->pNext = pBt->pCursor;
+  pBt->pCursor = pCur;
+  if( wrFlag ){
+    pCur->curFlags |= BTCF_WriteFlag;
+    pCur->curPagerFlags = 0;
+    if( pBt->pTmpSpace==0 ) return allocateTempSpace(pBt);
+  }else{
+    pCur->curPagerFlags = PAGER_GET_READONLY;
+  }
+  return SQLITE_OK;
+}
+static int btreeCursorWithLock(
+  Btree *p,                              /* The btree */
+  Pgno iTable,                           /* Root page of table to open */
+  int wrFlag,                            /* 1 to write. 0 read-only */
+  struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
+  BtCursor *pCur                         /* Space for new cursor */
+){
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeCursor(
+  Btree *p,                                   /* The btree */
+  Pgno iTable,                                /* Root page of table to open */
+  int wrFlag,                                 /* 1 to write. 0 read-only */
+  struct KeyInfo *pKeyInfo,                   /* First arg to xCompare() */
+  BtCursor *pCur                              /* Write new cursor here */
+){
+  if( p->sharable ){
+    return btreeCursorWithLock(p, iTable, wrFlag, pKeyInfo, pCur);
+  }else{
+    return btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
+  }
+}
+
+/*
+** Return the size of a BtCursor object in bytes.
+**
+** This interfaces is needed so that users of cursors can preallocate
+** sufficient storage to hold a cursor.  The BtCursor object is opaque
+** to users so they cannot do the sizeof() themselves - they must call
+** this routine.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorSize(void){
+  return ROUND8(sizeof(BtCursor));
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Return true if and only if the Btree object will be automatically
+** closed with the BtCursor closes.  This is used within assert() statements
+** only.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClosesWithCursor(
+  Btree *pBtree,       /* the btree object */
+  BtCursor *pCur       /* Corresponding cursor */
+){
+  BtShared *pBt = pBtree->pBt;
+  if( (pBt->openFlags & BTREE_SINGLE)==0 ) return 0;
+  if( pBt->pCursor!=pCur ) return 0;
+  if( pCur->pNext!=0 ) return 0;
+  if( pCur->pBtree!=pBtree ) return 0;
+  return 1;
+}
+#endif
+
+/*
+** Initialize memory that will be converted into a BtCursor object.
+**
+** The simple approach here would be to memset() the entire object
+** to zero.  But it turns out that the apPage[] and aiIdx[] arrays
+** do not need to be zeroed and they are large, so we can save a lot
+** of run-time by skipping the initialization of those elements.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor *p){
+  memset(p, 0, offsetof(BtCursor, BTCURSOR_FIRST_UNINIT));
+}
+
+/*
+** Close a cursor.  The read lock on the database file is released
+** when the last cursor is closed.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor *pCur){
+  Btree *pBtree = pCur->pBtree;
+  if( pBtree ){
+    BtShared *pBt = pCur->pBt;
+    sqlite3BtreeEnter(pBtree);
+    assert( pBt->pCursor!=0 );
+    if( pBt->pCursor==pCur ){
+      pBt->pCursor = pCur->pNext;
+    }else{
+      BtCursor *pPrev = pBt->pCursor;
+      do{
+        if( pPrev->pNext==pCur ){
+          pPrev->pNext = pCur->pNext;
+          break;
+        }
+        pPrev = pPrev->pNext;
+      }while( ALWAYS(pPrev) );
+    }
+    btreeReleaseAllCursorPages(pCur);
+    unlockBtreeIfUnused(pBt);
+    sqlite3_free(pCur->aOverflow);
+    sqlite3_free(pCur->pKey);
+    if( (pBt->openFlags & BTREE_SINGLE) && pBt->pCursor==0 ){
+      /* Since the BtShared is not sharable, there is no need to
+      ** worry about the missing sqlite3BtreeLeave() call here.  */
+      assert( pBtree->sharable==0 );
+      sqlite3BtreeClose(pBtree);
+    }else{
+      sqlite3BtreeLeave(pBtree);
+    }
+    pCur->pBtree = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Make sure the BtCursor* given in the argument has a valid
+** BtCursor.info structure.  If it is not already valid, call
+** btreeParseCell() to fill it in.
+**
+** BtCursor.info is a cache of the information in the current cell.
+** Using this cache reduces the number of calls to btreeParseCell().
+*/
+#ifndef NDEBUG
+  static int cellInfoEqual(CellInfo *a, CellInfo *b){
+    if( a->nKey!=b->nKey ) return 0;
+    if( a->pPayload!=b->pPayload ) return 0;
+    if( a->nPayload!=b->nPayload ) return 0;
+    if( a->nLocal!=b->nLocal ) return 0;
+    if( a->nSize!=b->nSize ) return 0;
+    return 1;
+  }
+  static void assertCellInfo(BtCursor *pCur){
+    CellInfo info;
+    memset(&info, 0, sizeof(info));
+    btreeParseCell(pCur->pPage, pCur->ix, &info);
+    assert( CORRUPT_DB || cellInfoEqual(&info, &pCur->info) );
+  }
+#else
+  #define assertCellInfo(x)
+#endif
+static SQLITE_NOINLINE void getCellInfo(BtCursor *pCur){
+  if( pCur->info.nSize==0 ){
+    pCur->curFlags |= BTCF_ValidNKey;
+    btreeParseCell(pCur->pPage,pCur->ix,&pCur->info);
+  }else{
+    assertCellInfo(pCur);
+  }
+}
+
+#ifndef NDEBUG  /* The next routine used only within assert() statements */
+/*
+** Return true if the given BtCursor is valid.  A valid cursor is one
+** that is currently pointing to a row in a (non-empty) table.
+** This is a verification routine is used only within assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValid(BtCursor *pCur){
+  return pCur && pCur->eState==CURSOR_VALID;
+}
+#endif /* NDEBUG */
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValidNN(BtCursor *pCur){
+  assert( pCur!=0 );
+  return pCur->eState==CURSOR_VALID;
+}
+
+/*
+** Return the value of the integer key or "rowid" for a table btree.
+** This routine is only valid for a cursor that is pointing into a
+** ordinary table btree.  If the cursor points to an index btree or
+** is invalid, the result of this routine is undefined.
+*/
+SQLITE_PRIVATE i64 sqlite3BtreeIntegerKey(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->curIntKey );
+  getCellInfo(pCur);
+  return pCur->info.nKey;
+}
+
+/*
+** Pin or unpin a cursor.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorPin(BtCursor *pCur){
+  assert( (pCur->curFlags & BTCF_Pinned)==0 );
+  pCur->curFlags |= BTCF_Pinned;
+}
+SQLITE_PRIVATE void sqlite3BtreeCursorUnpin(BtCursor *pCur){
+  assert( (pCur->curFlags & BTCF_Pinned)!=0 );
+  pCur->curFlags &= ~BTCF_Pinned;
+}
+
+/*
+** Return the offset into the database file for the start of the
+** payload to which the cursor is pointing.
+*/
+SQLITE_PRIVATE i64 sqlite3BtreeOffset(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  getCellInfo(pCur);
+  return (i64)pCur->pBt->pageSize*((i64)pCur->pPage->pgno - 1) +
+         (i64)(pCur->info.pPayload - pCur->pPage->aData);
+}
+
+/*
+** Return the number of bytes of payload for the entry that pCur is
+** currently pointing to.  For table btrees, this will be the amount
+** of data.  For index btrees, this will be the size of the key.
+**
+** The caller must guarantee that the cursor is pointing to a non-NULL
+** valid entry.  In other words, the calling procedure must guarantee
+** that the cursor has Cursor.eState==CURSOR_VALID.
+*/
+SQLITE_PRIVATE u32 sqlite3BtreePayloadSize(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  getCellInfo(pCur);
+  return pCur->info.nPayload;
+}
+
+/*
+** Return an upper bound on the size of any record for the table
+** that the cursor is pointing into.
+**
+** This is an optimization.  Everything will still work if this
+** routine always returns 2147483647 (which is the largest record
+** that SQLite can handle) or more.  But returning a smaller value might
+** prevent large memory allocations when trying to interpret a
+** corrupt database.
+**
+** The current implementation merely returns the size of the underlying
+** database file.
+*/
+SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  return pCur->pBt->pageSize * (sqlite3_int64)pCur->pBt->nPage;
+}
+
+/*
+** Given the page number of an overflow page in the database (parameter
+** ovfl), this function finds the page number of the next page in the
+** linked list of overflow pages. If possible, it uses the auto-vacuum
+** pointer-map data instead of reading the content of page ovfl to do so.
+**
+** If an error occurs an SQLite error code is returned. Otherwise:
+**
+** The page number of the next overflow page in the linked list is
+** written to *pPgnoNext. If page ovfl is the last page in its linked
+** list, *pPgnoNext is set to zero.
+**
+** If ppPage is not NULL, and a reference to the MemPage object corresponding
+** to page number pOvfl was obtained, then *ppPage is set to point to that
+** reference. It is the responsibility of the caller to call releasePage()
+** on *ppPage to free the reference. In no reference was obtained (because
+** the pointer-map was used to obtain the value for *pPgnoNext), then
+** *ppPage is set to zero.
+*/
+static int getOverflowPage(
+  BtShared *pBt,               /* The database file */
+  Pgno ovfl,                   /* Current overflow page number */
+  MemPage **ppPage,            /* OUT: MemPage handle (may be NULL) */
+  Pgno *pPgnoNext              /* OUT: Next overflow page number */
+){
+  Pgno next = 0;
+  MemPage *pPage = 0;
+  int rc = SQLITE_OK;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert(pPgnoNext);
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  /* Try to find the next page in the overflow list using the
+  ** autovacuum pointer-map pages. Guess that the next page in
+  ** the overflow list is page number (ovfl+1). If that guess turns
+  ** out to be wrong, fall back to loading the data of page
+  ** number ovfl to determine the next page number.
+  */
+  if( pBt->autoVacuum ){
+    Pgno pgno;
+    Pgno iGuess = ovfl+1;
+    u8 eType;
+
+    while( PTRMAP_ISPAGE(pBt, iGuess) || iGuess==PENDING_BYTE_PAGE(pBt) ){
+      iGuess++;
+    }
+
+    if( iGuess<=btreePagecount(pBt) ){
+      rc = ptrmapGet(pBt, iGuess, &eType, &pgno);
+      if( rc==SQLITE_OK && eType==PTRMAP_OVERFLOW2 && pgno==ovfl ){
+        next = iGuess;
+        rc = SQLITE_DONE;
+      }
+    }
+  }
+#endif
+
+  assert( next==0 || rc==SQLITE_DONE );
+  if( rc==SQLITE_OK ){
+    rc = btreeGetPage(pBt, ovfl, &pPage, (ppPage==0) ? PAGER_GET_READONLY : 0);
+    assert( rc==SQLITE_OK || pPage==0 );
+    if( rc==SQLITE_OK ){
+      next = get4byte(pPage->aData);
+    }
+  }
+
+  *pPgnoNext = next;
+  if( ppPage ){
+    *ppPage = pPage;
+  }else{
+    releasePage(pPage);
+  }
+  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
+}
+
+/*
+** Copy data from a buffer to a page, or from a page to a buffer.
+**
+** pPayload is a pointer to data stored on database page pDbPage.
+** If argument eOp is false, then nByte bytes of data are copied
+** from pPayload to the buffer pointed at by pBuf. If eOp is true,
+** then sqlite3PagerWrite() is called on pDbPage and nByte bytes
+** of data are copied from the buffer pBuf to pPayload.
+**
+** SQLITE_OK is returned on success, otherwise an error code.
+*/
+static int copyPayload(
+  void *pPayload,           /* Pointer to page data */
+  void *pBuf,               /* Pointer to buffer */
+  int nByte,                /* Number of bytes to copy */
+  int eOp,                  /* 0 -> copy from page, 1 -> copy to page */
+  DbPage *pDbPage           /* Page containing pPayload */
+){
+  if( eOp ){
+    /* Copy data from buffer to page (a write operation) */
+    int rc = sqlite3PagerWrite(pDbPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    memcpy(pPayload, pBuf, nByte);
+  }else{
+    /* Copy data from page to buffer (a read operation) */
+    memcpy(pBuf, pPayload, nByte);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is used to read or overwrite payload information
+** for the entry that the pCur cursor is pointing to. The eOp
+** argument is interpreted as follows:
+**
+**   0: The operation is a read. Populate the overflow cache.
+**   1: The operation is a write. Populate the overflow cache.
+**
+** A total of "amt" bytes are read or written beginning at "offset".
+** Data is read to or from the buffer pBuf.
+**
+** The content being read or written might appear on the main page
+** or be scattered out on multiple overflow pages.
+**
+** If the current cursor entry uses one or more overflow pages
+** this function may allocate space for and lazily populate
+** the overflow page-list cache array (BtCursor.aOverflow).
+** Subsequent calls use this cache to make seeking to the supplied offset
+** more efficient.
+**
+** Once an overflow page-list cache has been allocated, it must be
+** invalidated if some other cursor writes to the same table, or if
+** the cursor is moved to a different row. Additionally, in auto-vacuum
+** mode, the following events may invalidate an overflow page-list cache.
+**
+**   * An incremental vacuum,
+**   * A commit in auto_vacuum="full" mode,
+**   * Creating a table (may require moving an overflow page).
+*/
+static int accessPayload(
+  BtCursor *pCur,      /* Cursor pointing to entry to read from */
+  u32 offset,          /* Begin reading this far into payload */
+  u32 amt,             /* Read this many bytes */
+  unsigned char *pBuf, /* Write the bytes into this buffer */
+  int eOp              /* zero to read. non-zero to write. */
+){
+  unsigned char *aPayload;
+  int rc = SQLITE_OK;
+  int iIdx = 0;
+  MemPage *pPage = pCur->pPage;               /* Btree page of current entry */
+  BtShared *pBt = pCur->pBt;                  /* Btree this cursor belongs to */
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+  unsigned char * const pBufStart = pBuf;     /* Start of original out buffer */
+#endif
+
+  assert( pPage );
+  assert( eOp==0 || eOp==1 );
+  assert( pCur->eState==CURSOR_VALID );
+  if( pCur->ix>=pPage->nCell ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  assert( cursorHoldsMutex(pCur) );
+
+  getCellInfo(pCur);
+  aPayload = pCur->info.pPayload;
+  assert( offset+amt <= pCur->info.nPayload );
+
+  assert( aPayload > pPage->aData );
+  if( (uptr)(aPayload - pPage->aData) > (pBt->usableSize - pCur->info.nLocal) ){
+    /* Trying to read or write past the end of the data is an error.  The
+    ** conditional above is really:
+    **    &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
+    ** but is recast into its current form to avoid integer overflow problems
+    */
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+
+  /* Check if data must be read/written to/from the btree page itself. */
+  if( offset<pCur->info.nLocal ){
+    int a = amt;
+    if( a+offset>pCur->info.nLocal ){
+      a = pCur->info.nLocal - offset;
+    }
+    rc = copyPayload(&aPayload[offset], pBuf, a, eOp, pPage->pDbPage);
+    offset = 0;
+    pBuf += a;
+    amt -= a;
+  }else{
+    offset -= pCur->info.nLocal;
+  }
+
+
+  if( rc==SQLITE_OK && amt>0 ){
+    const u32 ovflSize = pBt->usableSize - 4;  /* Bytes content per ovfl page */
+    Pgno nextPage;
+
+    nextPage = get4byte(&aPayload[pCur->info.nLocal]);
+
+    /* If the BtCursor.aOverflow[] has not been allocated, allocate it now.
+    **
+    ** The aOverflow[] array is sized at one entry for each overflow page
+    ** in the overflow chain. The page number of the first overflow page is
+    ** stored in aOverflow[0], etc. A value of 0 in the aOverflow[] array
+    ** means "not yet known" (the cache is lazily populated).
+    */
+    if( (pCur->curFlags & BTCF_ValidOvfl)==0 ){
+      int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
+      if( pCur->aOverflow==0
+       || nOvfl*(int)sizeof(Pgno) > sqlite3MallocSize(pCur->aOverflow)
+      ){
+        Pgno *aNew;
+        if( sqlite3FaultSim(413) ){
+          aNew = 0;
+        }else{
+          aNew = (Pgno*)sqlite3Realloc(pCur->aOverflow, nOvfl*2*sizeof(Pgno));
+        }
+        if( aNew==0 ){
+          return SQLITE_NOMEM_BKPT;
+        }else{
+          pCur->aOverflow = aNew;
+        }
+      }
+      memset(pCur->aOverflow, 0, nOvfl*sizeof(Pgno));
+      pCur->curFlags |= BTCF_ValidOvfl;
+    }else{
+      /* Sanity check the validity of the overflow page cache */
+      assert( pCur->aOverflow[0]==nextPage
+           || pCur->aOverflow[0]==0
+           || CORRUPT_DB );
+      assert( pCur->aOverflow[0]!=0 || pCur->aOverflow[offset/ovflSize]==0 );
+
+      /* If the overflow page-list cache has been allocated and the
+      ** entry for the first required overflow page is valid, skip
+      ** directly to it.
+      */
+      if( pCur->aOverflow[offset/ovflSize] ){
+        iIdx = (offset/ovflSize);
+        nextPage = pCur->aOverflow[iIdx];
+        offset = (offset%ovflSize);
+      }
+    }
+
+    assert( rc==SQLITE_OK && amt>0 );
+    while( nextPage ){
+      /* If required, populate the overflow page-list cache. */
+      if( nextPage > pBt->nPage ) return SQLITE_CORRUPT_BKPT;
+      assert( pCur->aOverflow[iIdx]==0
+              || pCur->aOverflow[iIdx]==nextPage
+              || CORRUPT_DB );
+      pCur->aOverflow[iIdx] = nextPage;
+
+      if( offset>=ovflSize ){
+        /* The only reason to read this page is to obtain the page
+        ** number for the next page in the overflow chain. The page
+        ** data is not required. So first try to lookup the overflow
+        ** page-list cache, if any, then fall back to the getOverflowPage()
+        ** function.
+        */
+        assert( pCur->curFlags & BTCF_ValidOvfl );
+        assert( pCur->pBtree->db==pBt->db );
+        if( pCur->aOverflow[iIdx+1] ){
+          nextPage = pCur->aOverflow[iIdx+1];
+        }else{
+          rc = getOverflowPage(pBt, nextPage, 0, &nextPage);
+        }
+        offset -= ovflSize;
+      }else{
+        /* Need to read this page properly. It contains some of the
+        ** range of data that is being read (eOp==0) or written (eOp!=0).
+        */
+        int a = amt;
+        if( a + offset > ovflSize ){
+          a = ovflSize - offset;
+        }
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+        /* If all the following are true:
+        **
+        **   1) this is a read operation, and
+        **   2) data is required from the start of this overflow page, and
+        **   3) there are no dirty pages in the page-cache
+        **   4) the database is file-backed, and
+        **   5) the page is not in the WAL file
+        **   6) at least 4 bytes have already been read into the output buffer
+        **
+        ** then data can be read directly from the database file into the
+        ** output buffer, bypassing the page-cache altogether. This speeds
+        ** up loading large records that span many overflow pages.
+        */
+        if( eOp==0                                             /* (1) */
+         && offset==0                                          /* (2) */
+         && sqlite3PagerDirectReadOk(pBt->pPager, nextPage)    /* (3,4,5) */
+         && &pBuf[-4]>=pBufStart                               /* (6) */
+        ){
+          sqlite3_file *fd = sqlite3PagerFile(pBt->pPager);
+          u8 aSave[4];
+          u8 *aWrite = &pBuf[-4];
+          assert( aWrite>=pBufStart );                         /* due to (6) */
+          memcpy(aSave, aWrite, 4);
+          rc = sqlite3OsRead(fd, aWrite, a+4, (i64)pBt->pageSize*(nextPage-1));
+          nextPage = get4byte(aWrite);
+          memcpy(aWrite, aSave, 4);
+        }else
+#endif
+
+        {
+          DbPage *pDbPage;
+          rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage,
+              (eOp==0 ? PAGER_GET_READONLY : 0)
+          );
+          if( rc==SQLITE_OK ){
+            aPayload = sqlite3PagerGetData(pDbPage);
+            nextPage = get4byte(aPayload);
+            rc = copyPayload(&aPayload[offset+4], pBuf, a, eOp, pDbPage);
+            sqlite3PagerUnref(pDbPage);
+            offset = 0;
+          }
+        }
+        amt -= a;
+        if( amt==0 ) return rc;
+        pBuf += a;
+      }
+      if( rc ) break;
+      iIdx++;
+    }
+  }
+
+  if( rc==SQLITE_OK && amt>0 ){
+    /* Overflow chain ends prematurely */
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  return rc;
+}
+
+/*
+** Read part of the payload for the row at which that cursor pCur is currently
+** pointing.  "amt" bytes will be transferred into pBuf[].  The transfer
+** begins at "offset".
+**
+** pCur can be pointing to either a table or an index b-tree.
+** If pointing to a table btree, then the content section is read.  If
+** pCur is pointing to an index b-tree then the key section is read.
+**
+** For sqlite3BtreePayload(), the caller must ensure that pCur is pointing
+** to a valid row in the table.  For sqlite3BtreePayloadChecked(), the
+** cursor might be invalid or might need to be restored before being read.
+**
+** Return SQLITE_OK on success or an error code if anything goes
+** wrong.  An error is returned if "offset+amt" is larger than
+** the available payload.
+*/
+SQLITE_PRIVATE int sqlite3BtreePayload(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->iPage>=0 && pCur->pPage );
+  return accessPayload(pCur, offset, amt, (unsigned char*)pBuf, 0);
+}
+
+/*
+** This variant of sqlite3BtreePayload() works even if the cursor has not
+** in the CURSOR_VALID state.  It is only used by the sqlite3_blob_read()
+** interface.
+*/
+#ifndef SQLITE_OMIT_INCRBLOB
+static SQLITE_NOINLINE int accessPayloadChecked(
+  BtCursor *pCur,
+  u32 offset,
+  u32 amt,
+  void *pBuf
+){
+  int rc;
+  if ( pCur->eState==CURSOR_INVALID ){
+    return SQLITE_ABORT;
+  }
+  assert( cursorOwnsBtShared(pCur) );
+  rc = btreeRestoreCursorPosition(pCur);
+  return rc ? rc : accessPayload(pCur, offset, amt, pBuf, 0);
+}
+SQLITE_PRIVATE int sqlite3BtreePayloadChecked(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
+  if( pCur->eState==CURSOR_VALID ){
+    assert( cursorOwnsBtShared(pCur) );
+    return accessPayload(pCur, offset, amt, pBuf, 0);
+  }else{
+    return accessPayloadChecked(pCur, offset, amt, pBuf);
+  }
+}
+#endif /* SQLITE_OMIT_INCRBLOB */
+
+/*
+** Return a pointer to payload information from the entry that the
+** pCur cursor is pointing to.  The pointer is to the beginning of
+** the key if index btrees (pPage->intKey==0) and is the data for
+** table btrees (pPage->intKey==1). The number of bytes of available
+** key/data is written into *pAmt.  If *pAmt==0, then the value
+** returned will not be a valid pointer.
+**
+** This routine is an optimization.  It is common for the entire key
+** and data to fit on the local page and for there to be no overflow
+** pages.  When that is so, this routine can be used to access the
+** key and data without making a copy.  If the key and/or data spills
+** onto overflow pages, then accessPayload() must be used to reassemble
+** the key/data and copy it into a preallocated buffer.
+**
+** The pointer returned by this routine looks directly into the cached
+** page of the database.  The data might change or move the next time
+** any btree routine is called.
+*/
+static const void *fetchPayload(
+  BtCursor *pCur,      /* Cursor pointing to entry to read from */
+  u32 *pAmt            /* Write the number of available bytes here */
+){
+  int amt;
+  assert( pCur!=0 && pCur->iPage>=0 && pCur->pPage);
+  assert( pCur->eState==CURSOR_VALID );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->ix<pCur->pPage->nCell || CORRUPT_DB );
+  assert( pCur->info.nSize>0 );
+  assert( pCur->info.pPayload>pCur->pPage->aData || CORRUPT_DB );
+  assert( pCur->info.pPayload<pCur->pPage->aDataEnd ||CORRUPT_DB);
+  amt = pCur->info.nLocal;
+  if( amt>(int)(pCur->pPage->aDataEnd - pCur->info.pPayload) ){
+    /* There is too little space on the page for the expected amount
+    ** of local content. Database must be corrupt. */
+    assert( CORRUPT_DB );
+    amt = MAX(0, (int)(pCur->pPage->aDataEnd - pCur->info.pPayload));
+  }
+  *pAmt = (u32)amt;
+  return (void*)pCur->info.pPayload;
+}
+
+
+/*
+** For the entry that cursor pCur is point to, return as
+** many bytes of the key or data as are available on the local
+** b-tree page.  Write the number of available bytes into *pAmt.
+**
+** The pointer returned is ephemeral.  The key/data may move
+** or be destroyed on the next call to any Btree routine,
+** including calls from other threads against the same cache.
+** Hence, a mutex on the BtShared should be held prior to calling
+** this routine.
+**
+** These routines is used to get quick access to key and data
+** in the common case where no overflow pages are used.
+*/
+SQLITE_PRIVATE const void *sqlite3BtreePayloadFetch(BtCursor *pCur, u32 *pAmt){
+  return fetchPayload(pCur, pAmt);
+}
+
+
+/*
+** Move the cursor down to a new child page.  The newPgno argument is the
+** page number of the child page to move to.
+**
+** This function returns SQLITE_CORRUPT if the page-header flags field of
+** the new child page does not match the flags field of the parent (i.e.
+** if an intkey page appears to be the parent of a non-intkey page, or
+** vice-versa).
+*/
+static int moveToChild(BtCursor *pCur, u32 newPgno){
+  int rc;
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
+  assert( pCur->iPage>=0 );
+  if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  pCur->info.nSize = 0;
+  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+  pCur->aiIdx[pCur->iPage] = pCur->ix;
+  pCur->apPage[pCur->iPage] = pCur->pPage;
+  pCur->ix = 0;
+  pCur->iPage++;
+  rc = getAndInitPage(pCur->pBt, newPgno, &pCur->pPage, pCur->curPagerFlags);
+  assert( pCur->pPage!=0 || rc!=SQLITE_OK );
+  if( rc==SQLITE_OK
+   && (pCur->pPage->nCell<1 || pCur->pPage->intKey!=pCur->curIntKey)
+  ){
+    releasePage(pCur->pPage);
+    rc = SQLITE_CORRUPT_PGNO(newPgno);
+  }
+  if( rc ){
+    pCur->pPage = pCur->apPage[--pCur->iPage];
+  }
+  return rc;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Page pParent is an internal (non-leaf) tree page. This function
+** asserts that page number iChild is the left-child if the iIdx'th
+** cell in page pParent. Or, if iIdx is equal to the total number of
+** cells in pParent, that page number iChild is the right-child of
+** the page.
+*/
+static void assertParentIndex(MemPage *pParent, int iIdx, Pgno iChild){
+  if( CORRUPT_DB ) return;  /* The conditions tested below might not be true
+                            ** in a corrupt database */
+  assert( iIdx<=pParent->nCell );
+  if( iIdx==pParent->nCell ){
+    assert( get4byte(&pParent->aData[pParent->hdrOffset+8])==iChild );
+  }else{
+    assert( get4byte(findCell(pParent, iIdx))==iChild );
+  }
+}
+#else
+#  define assertParentIndex(x,y,z)
+#endif
+
+/*
+** Move the cursor up to the parent page.
+**
+** pCur->idx is set to the cell index that contains the pointer
+** to the page we are coming from.  If we are coming from the
+** right-most child page then pCur->idx is set to one more than
+** the largest cell index.
+*/
+static void moveToParent(BtCursor *pCur){
+  MemPage *pLeaf;
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->iPage>0 );
+  assert( pCur->pPage );
+  assertParentIndex(
+    pCur->apPage[pCur->iPage-1],
+    pCur->aiIdx[pCur->iPage-1],
+    pCur->pPage->pgno
+  );
+  testcase( pCur->aiIdx[pCur->iPage-1] > pCur->apPage[pCur->iPage-1]->nCell );
+  pCur->info.nSize = 0;
+  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+  pCur->ix = pCur->aiIdx[pCur->iPage-1];
+  pLeaf = pCur->pPage;
+  pCur->pPage = pCur->apPage[--pCur->iPage];
+  releasePageNotNull(pLeaf);
+}
+
+/*
+** Move the cursor to point to the root page of its b-tree structure.
+**
+** If the table has a virtual root page, then the cursor is moved to point
+** to the virtual root page instead of the actual root page. A table has a
+** virtual root page when the actual root page contains no cells and a
+** single child page. This can only happen with the table rooted at page 1.
+**
+** If the b-tree structure is empty, the cursor state is set to
+** CURSOR_INVALID and this routine returns SQLITE_EMPTY. Otherwise,
+** the cursor is set to point to the first cell located on the root
+** (or virtual root) page and the cursor state is set to CURSOR_VALID.
+**
+** If this function returns successfully, it may be assumed that the
+** page-header flags indicate that the [virtual] root-page is the expected
+** kind of b-tree page (i.e. if when opening the cursor the caller did not
+** specify a KeyInfo structure the flags byte is set to 0x05 or 0x0D,
+** indicating a table b-tree, or if the caller did specify a KeyInfo
+** structure the flags byte is set to 0x02 or 0x0A, indicating an index
+** b-tree).
+*/
+static int moveToRoot(BtCursor *pCur){
+  MemPage *pRoot;
+  int rc = SQLITE_OK;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( CURSOR_INVALID < CURSOR_REQUIRESEEK );
+  assert( CURSOR_VALID   < CURSOR_REQUIRESEEK );
+  assert( CURSOR_FAULT   > CURSOR_REQUIRESEEK );
+  assert( pCur->eState < CURSOR_REQUIRESEEK || pCur->iPage<0 );
+  assert( pCur->pgnoRoot>0 || pCur->iPage<0 );
+
+  if( pCur->iPage>=0 ){
+    if( pCur->iPage ){
+      releasePageNotNull(pCur->pPage);
+      while( --pCur->iPage ){
+        releasePageNotNull(pCur->apPage[pCur->iPage]);
+      }
+      pRoot = pCur->pPage = pCur->apPage[0];
+      goto skip_init;
+    }
+  }else if( pCur->pgnoRoot==0 ){
+    pCur->eState = CURSOR_INVALID;
+    return SQLITE_EMPTY;
+  }else{
+    assert( pCur->iPage==(-1) );
+    if( pCur->eState>=CURSOR_REQUIRESEEK ){
+      if( pCur->eState==CURSOR_FAULT ){
+        assert( pCur->skipNext!=SQLITE_OK );
+        return pCur->skipNext;
+      }
+      sqlite3BtreeClearCursor(pCur);
+    }
+    rc = getAndInitPage(pCur->pBt, pCur->pgnoRoot, &pCur->pPage,
+                        pCur->curPagerFlags);
+    if( rc!=SQLITE_OK ){
+      pCur->eState = CURSOR_INVALID;
+      return rc;
+    }
+    pCur->iPage = 0;
+    pCur->curIntKey = pCur->pPage->intKey;
+  }
+  pRoot = pCur->pPage;
+  assert( pRoot->pgno==pCur->pgnoRoot || CORRUPT_DB );
+
+  /* If pCur->pKeyInfo is not NULL, then the caller that opened this cursor
+  ** expected to open it on an index b-tree. Otherwise, if pKeyInfo is
+  ** NULL, the caller expects a table b-tree. If this is not the case,
+  ** return an SQLITE_CORRUPT error.
+  **
+  ** Earlier versions of SQLite assumed that this test could not fail
+  ** if the root page was already loaded when this function was called (i.e.
+  ** if pCur->iPage>=0). But this is not so if the database is corrupted
+  ** in such a way that page pRoot is linked into a second b-tree table
+  ** (or the freelist).  */
+  assert( pRoot->intKey==1 || pRoot->intKey==0 );
+  if( pRoot->isInit==0 || (pCur->pKeyInfo==0)!=pRoot->intKey ){
+    return SQLITE_CORRUPT_PAGE(pCur->pPage);
+  }
+
+skip_init:
+  pCur->ix = 0;
+  pCur->info.nSize = 0;
+  pCur->curFlags &= ~(BTCF_AtLast|BTCF_ValidNKey|BTCF_ValidOvfl);
+
+  if( pRoot->nCell>0 ){
+    pCur->eState = CURSOR_VALID;
+  }else if( !pRoot->leaf ){
+    Pgno subpage;
+    if( pRoot->pgno!=1 ) return SQLITE_CORRUPT_BKPT;
+    subpage = get4byte(&pRoot->aData[pRoot->hdrOffset+8]);
+    pCur->eState = CURSOR_VALID;
+    rc = moveToChild(pCur, subpage);
+  }else{
+    pCur->eState = CURSOR_INVALID;
+    rc = SQLITE_EMPTY;
+  }
+  return rc;
+}
+
+/*
+** Move the cursor down to the left-most leaf entry beneath the
+** entry to which it is currently pointing.
+**
+** The left-most leaf is the one with the smallest key - the first
+** in ascending order.
+*/
+static int moveToLeftmost(BtCursor *pCur){
+  Pgno pgno;
+  int rc = SQLITE_OK;
+  MemPage *pPage;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  while( rc==SQLITE_OK && !(pPage = pCur->pPage)->leaf ){
+    assert( pCur->ix<pPage->nCell );
+    pgno = get4byte(findCell(pPage, pCur->ix));
+    rc = moveToChild(pCur, pgno);
+  }
+  return rc;
+}
+
+/*
+** Move the cursor down to the right-most leaf entry beneath the
+** page to which it is currently pointing.  Notice the difference
+** between moveToLeftmost() and moveToRightmost().  moveToLeftmost()
+** finds the left-most entry beneath the *entry* whereas moveToRightmost()
+** finds the right-most entry beneath the *page*.
+**
+** The right-most entry is the one with the largest key - the last
+** key in ascending order.
+*/
+static int moveToRightmost(BtCursor *pCur){
+  Pgno pgno;
+  int rc = SQLITE_OK;
+  MemPage *pPage = 0;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  while( !(pPage = pCur->pPage)->leaf ){
+    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    pCur->ix = pPage->nCell;
+    rc = moveToChild(pCur, pgno);
+    if( rc ) return rc;
+  }
+  pCur->ix = pPage->nCell-1;
+  assert( pCur->info.nSize==0 );
+  assert( (pCur->curFlags & BTCF_ValidNKey)==0 );
+  return SQLITE_OK;
+}
+
+/* Move the cursor to the first entry in the table.  Return SQLITE_OK
+** on success.  Set *pRes to 0 if the cursor actually points to something
+** or set *pRes to 1 if the table is empty.
+*/
+SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
+  int rc;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  rc = moveToRoot(pCur);
+  if( rc==SQLITE_OK ){
+    assert( pCur->pPage->nCell>0 );
+    *pRes = 0;
+    rc = moveToLeftmost(pCur);
+  }else if( rc==SQLITE_EMPTY ){
+    assert( pCur->pgnoRoot==0 || (pCur->pPage!=0 && pCur->pPage->nCell==0) );
+    *pRes = 1;
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+
+#ifdef SQLITE_DEBUG
+/* The cursors is CURSOR_VALID and has BTCF_AtLast set.  Verify that
+** this flags are true for a consistent database.
+**
+** This routine is is called from within assert() statements only.
+** It is an internal verification routine and does not appear in production
+** builds.
+*/
+static int cursorIsAtLastEntry(BtCursor *pCur){
+  int ii;
+  for(ii=0; ii<pCur->iPage; ii++){
+    if( pCur->aiIdx[ii]!=pCur->apPage[ii]->nCell ) return 0;
+  }
+  return pCur->ix==pCur->pPage->nCell-1 && pCur->pPage->leaf!=0;
+}
+#endif
+
+/* Move the cursor to the last entry in the table.  Return SQLITE_OK
+** on success.  Set *pRes to 0 if the cursor actually points to something
+** or set *pRes to 1 if the table is empty.
+*/
+static SQLITE_NOINLINE int btreeLast(BtCursor *pCur, int *pRes){
+  int rc = moveToRoot(pCur);
+  if( rc==SQLITE_OK ){
+    assert( pCur->eState==CURSOR_VALID );
+    *pRes = 0;
+    rc = moveToRightmost(pCur);
+    if( rc==SQLITE_OK ){
+      pCur->curFlags |= BTCF_AtLast;
+    }else{
+      pCur->curFlags &= ~BTCF_AtLast;
+    }
+  }else if( rc==SQLITE_EMPTY ){
+    assert( pCur->pgnoRoot==0 || pCur->pPage->nCell==0 );
+    *pRes = 1;
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor *pCur, int *pRes){
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+
+  /* If the cursor already points to the last entry, this is a no-op. */
+  if( CURSOR_VALID==pCur->eState && (pCur->curFlags & BTCF_AtLast)!=0 ){
+    assert( cursorIsAtLastEntry(pCur) || CORRUPT_DB );
+    *pRes = 0;
+    return SQLITE_OK;
+  }
+  return btreeLast(pCur, pRes);
+}
+
+/* Move the cursor so that it points to an entry in a table (a.k.a INTKEY)
+** table near the key intKey.   Return a success code.
+**
+** If an exact match is not found, then the cursor is always
+** left pointing at a leaf page which would hold the entry if it
+** were present.  The cursor might point to an entry that comes
+** before or after the key.
+**
+** An integer is written into *pRes which is the result of
+** comparing the key with the entry to which the cursor is
+** pointing.  The meaning of the integer written into
+** *pRes is as follows:
+**
+**     *pRes<0      The cursor is left pointing at an entry that
+**                  is smaller than intKey or if the table is empty
+**                  and the cursor is therefore left point to nothing.
+**
+**     *pRes==0     The cursor is left pointing at an entry that
+**                  exactly matches intKey.
+**
+**     *pRes>0      The cursor is left pointing at an entry that
+**                  is larger than intKey.
+*/
+SQLITE_PRIVATE int sqlite3BtreeTableMoveto(
+  BtCursor *pCur,          /* The cursor to be moved */
+  i64 intKey,              /* The table key */
+  int biasRight,           /* If true, bias the search to the high end */
+  int *pRes                /* Write search results here */
+){
+  int rc;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  assert( pRes );
+  assert( pCur->pKeyInfo==0 );
+  assert( pCur->eState!=CURSOR_VALID || pCur->curIntKey!=0 );
+
+  /* If the cursor is already positioned at the point we are trying
+  ** to move to, then just return without doing any work */
+  if( pCur->eState==CURSOR_VALID && (pCur->curFlags & BTCF_ValidNKey)!=0 ){
+    if( pCur->info.nKey==intKey ){
+      *pRes = 0;
+      return SQLITE_OK;
+    }
+    if( pCur->info.nKey<intKey ){
+      if( (pCur->curFlags & BTCF_AtLast)!=0 ){
+        assert( cursorIsAtLastEntry(pCur) || CORRUPT_DB );
+        *pRes = -1;
+        return SQLITE_OK;
+      }
+      /* If the requested key is one more than the previous key, then
+      ** try to get there using sqlite3BtreeNext() rather than a full
+      ** binary search.  This is an optimization only.  The correct answer
+      ** is still obtained without this case, only a little more slowly. */
+      if( pCur->info.nKey+1==intKey ){
+        *pRes = 0;
+        rc = sqlite3BtreeNext(pCur, 0);
+        if( rc==SQLITE_OK ){
+          getCellInfo(pCur);
+          if( pCur->info.nKey==intKey ){
+            return SQLITE_OK;
+          }
+        }else if( rc!=SQLITE_DONE ){
+          return rc;
+        }
+      }
+    }
+  }
+
+#ifdef SQLITE_DEBUG
+  pCur->pBtree->nSeek++;   /* Performance measurement during testing */
+#endif
+
+  rc = moveToRoot(pCur);
+  if( rc ){
+    if( rc==SQLITE_EMPTY ){
+      assert( pCur->pgnoRoot==0 || pCur->pPage->nCell==0 );
+      *pRes = -1;
+      return SQLITE_OK;
+    }
+    return rc;
+  }
+  assert( pCur->pPage );
+  assert( pCur->pPage->isInit );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->pPage->nCell > 0 );
+  assert( pCur->iPage==0 || pCur->apPage[0]->intKey==pCur->curIntKey );
+  assert( pCur->curIntKey );
+
+  for(;;){
+    int lwr, upr, idx, c;
+    Pgno chldPg;
+    MemPage *pPage = pCur->pPage;
+    u8 *pCell;                          /* Pointer to current cell in pPage */
+
+    /* pPage->nCell must be greater than zero. If this is the root-page
+    ** the cursor would have been INVALID above and this for(;;) loop
+    ** not run. If this is not the root-page, then the moveToChild() routine
+    ** would have already detected db corruption. Similarly, pPage must
+    ** be the right kind (index or table) of b-tree page. Otherwise
+    ** a moveToChild() or moveToRoot() call would have detected corruption.  */
+    assert( pPage->nCell>0 );
+    assert( pPage->intKey );
+    lwr = 0;
+    upr = pPage->nCell-1;
+    assert( biasRight==0 || biasRight==1 );
+    idx = upr>>(1-biasRight); /* idx = biasRight ? upr : (lwr+upr)/2; */
+    for(;;){
+      i64 nCellKey;
+      pCell = findCellPastPtr(pPage, idx);
+      if( pPage->intKeyLeaf ){
+        while( 0x80 <= *(pCell++) ){
+          if( pCell>=pPage->aDataEnd ){
+            return SQLITE_CORRUPT_PAGE(pPage);
+          }
+        }
+      }
+      getVarint(pCell, (u64*)&nCellKey);
+      if( nCellKey<intKey ){
+        lwr = idx+1;
+        if( lwr>upr ){ c = -1; break; }
+      }else if( nCellKey>intKey ){
+        upr = idx-1;
+        if( lwr>upr ){ c = +1; break; }
+      }else{
+        assert( nCellKey==intKey );
+        pCur->ix = (u16)idx;
+        if( !pPage->leaf ){
+          lwr = idx;
+          goto moveto_table_next_layer;
+        }else{
+          pCur->curFlags |= BTCF_ValidNKey;
+          pCur->info.nKey = nCellKey;
+          pCur->info.nSize = 0;
+          *pRes = 0;
+          return SQLITE_OK;
+        }
+      }
+      assert( lwr+upr>=0 );
+      idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2; */
+    }
+    assert( lwr==upr+1 || !pPage->leaf );
+    assert( pPage->isInit );
+    if( pPage->leaf ){
+      assert( pCur->ix<pCur->pPage->nCell );
+      pCur->ix = (u16)idx;
+      *pRes = c;
+      rc = SQLITE_OK;
+      goto moveto_table_finish;
+    }
+moveto_table_next_layer:
+    if( lwr>=pPage->nCell ){
+      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    }else{
+      chldPg = get4byte(findCell(pPage, lwr));
+    }
+    pCur->ix = (u16)lwr;
+    rc = moveToChild(pCur, chldPg);
+    if( rc ) break;
+  }
+moveto_table_finish:
+  pCur->info.nSize = 0;
+  assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
+  return rc;
+}
+
+/*
+** Compare the "idx"-th cell on the page the cursor pCur is currently
+** pointing to to pIdxKey using xRecordCompare.  Return negative or
+** zero if the cell is less than or equal pIdxKey.  Return positive
+** if unknown.
+**
+**    Return value negative:     Cell at pCur[idx] less than pIdxKey
+**
+**    Return value is zero:      Cell at pCur[idx] equals pIdxKey
+**
+**    Return value positive:     Nothing is known about the relationship
+**                               of the cell at pCur[idx] and pIdxKey.
+**
+** This routine is part of an optimization.  It is always safe to return
+** a positive value as that will cause the optimization to be skipped.
+*/
+static int indexCellCompare(
+  BtCursor *pCur,
+  int idx,
+  UnpackedRecord *pIdxKey,
+  RecordCompare xRecordCompare
+){
+  MemPage *pPage = pCur->pPage;
+  int c;
+  int nCell;  /* Size of the pCell cell in bytes */
+  u8 *pCell = findCellPastPtr(pPage, idx);
+
+  nCell = pCell[0];
+  if( nCell<=pPage->max1bytePayload ){
+    /* This branch runs if the record-size field of the cell is a
+    ** single byte varint and the record fits entirely on the main
+    ** b-tree page.  */
+    testcase( pCell+nCell+1==pPage->aDataEnd );
+    c = xRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
+  }else if( !(pCell[1] & 0x80)
+    && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
+  ){
+    /* The record-size field is a 2 byte varint and the record
+    ** fits entirely on the main b-tree page.  */
+    testcase( pCell+nCell+2==pPage->aDataEnd );
+    c = xRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
+  }else{
+    /* If the record extends into overflow pages, do not attempt
+    ** the optimization. */
+    c = 99;
+  }
+  return c;
+}
+
+/*
+** Return true (non-zero) if pCur is current pointing to the last
+** page of a table.
+*/
+static int cursorOnLastPage(BtCursor *pCur){
+  int i;
+  assert( pCur->eState==CURSOR_VALID );
+  for(i=0; i<pCur->iPage; i++){
+    MemPage *pPage = pCur->apPage[i];
+    if( pCur->aiIdx[i]<pPage->nCell ) return 0;
+  }
+  return 1;
+}
+
+/* Move the cursor so that it points to an entry in an index table
+** near the key pIdxKey.   Return a success code.
+**
+** If an exact match is not found, then the cursor is always
+** left pointing at a leaf page which would hold the entry if it
+** were present.  The cursor might point to an entry that comes
+** before or after the key.
+**
+** An integer is written into *pRes which is the result of
+** comparing the key with the entry to which the cursor is
+** pointing.  The meaning of the integer written into
+** *pRes is as follows:
+**
+**     *pRes<0      The cursor is left pointing at an entry that
+**                  is smaller than pIdxKey or if the table is empty
+**                  and the cursor is therefore left point to nothing.
+**
+**     *pRes==0     The cursor is left pointing at an entry that
+**                  exactly matches pIdxKey.
+**
+**     *pRes>0      The cursor is left pointing at an entry that
+**                  is larger than pIdxKey.
+**
+** The pIdxKey->eqSeen field is set to 1 if there
+** exists an entry in the table that exactly matches pIdxKey.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIndexMoveto(
+  BtCursor *pCur,          /* The cursor to be moved */
+  UnpackedRecord *pIdxKey, /* Unpacked index key */
+  int *pRes                /* Write search results here */
+){
+  int rc;
+  RecordCompare xRecordCompare;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  assert( pRes );
+  assert( pCur->pKeyInfo!=0 );
+
+#ifdef SQLITE_DEBUG
+  pCur->pBtree->nSeek++;   /* Performance measurement during testing */
+#endif
+
+  xRecordCompare = sqlite3VdbeFindCompare(pIdxKey);
+  pIdxKey->errCode = 0;
+  assert( pIdxKey->default_rc==1
+       || pIdxKey->default_rc==0
+       || pIdxKey->default_rc==-1
+  );
+
+
+  /* Check to see if we can skip a lot of work.  Two cases:
+  **
+  **    (1) If the cursor is already pointing to the very last cell
+  **        in the table and the pIdxKey search key is greater than or
+  **        equal to that last cell, then no movement is required.
+  **
+  **    (2) If the cursor is on the last page of the table and the first
+  **        cell on that last page is less than or equal to the pIdxKey
+  **        search key, then we can start the search on the current page
+  **        without needing to go back to root.
+  */
+  if( pCur->eState==CURSOR_VALID
+   && pCur->pPage->leaf
+   && cursorOnLastPage(pCur)
+  ){
+    int c;
+    if( pCur->ix==pCur->pPage->nCell-1
+     && (c = indexCellCompare(pCur, pCur->ix, pIdxKey, xRecordCompare))<=0
+     && pIdxKey->errCode==SQLITE_OK
+    ){
+      *pRes = c;
+      return SQLITE_OK;  /* Cursor already pointing at the correct spot */
+    }
+    if( pCur->iPage>0
+     && indexCellCompare(pCur, 0, pIdxKey, xRecordCompare)<=0
+     && pIdxKey->errCode==SQLITE_OK
+    ){
+      pCur->curFlags &= ~(BTCF_ValidOvfl|BTCF_AtLast);
+      if( !pCur->pPage->isInit ){
+        return SQLITE_CORRUPT_BKPT;
+      }
+      goto bypass_moveto_root;  /* Start search on the current page */
+    }
+    pIdxKey->errCode = SQLITE_OK;
+  }
+
+  rc = moveToRoot(pCur);
+  if( rc ){
+    if( rc==SQLITE_EMPTY ){
+      assert( pCur->pgnoRoot==0 || pCur->pPage->nCell==0 );
+      *pRes = -1;
+      return SQLITE_OK;
+    }
+    return rc;
+  }
+
+bypass_moveto_root:
+  assert( pCur->pPage );
+  assert( pCur->pPage->isInit );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->pPage->nCell > 0 );
+  assert( pCur->curIntKey==0 );
+  assert( pIdxKey!=0 );
+  for(;;){
+    int lwr, upr, idx, c;
+    Pgno chldPg;
+    MemPage *pPage = pCur->pPage;
+    u8 *pCell;                          /* Pointer to current cell in pPage */
+
+    /* pPage->nCell must be greater than zero. If this is the root-page
+    ** the cursor would have been INVALID above and this for(;;) loop
+    ** not run. If this is not the root-page, then the moveToChild() routine
+    ** would have already detected db corruption. Similarly, pPage must
+    ** be the right kind (index or table) of b-tree page. Otherwise
+    ** a moveToChild() or moveToRoot() call would have detected corruption.  */
+    assert( pPage->nCell>0 );
+    assert( pPage->intKey==0 );
+    lwr = 0;
+    upr = pPage->nCell-1;
+    idx = upr>>1; /* idx = (lwr+upr)/2; */
+    for(;;){
+      int nCell;  /* Size of the pCell cell in bytes */
+      pCell = findCellPastPtr(pPage, idx);
+
+      /* The maximum supported page-size is 65536 bytes. This means that
+      ** the maximum number of record bytes stored on an index B-Tree
+      ** page is less than 16384 bytes and may be stored as a 2-byte
+      ** varint. This information is used to attempt to avoid parsing
+      ** the entire cell by checking for the cases where the record is
+      ** stored entirely within the b-tree page by inspecting the first
+      ** 2 bytes of the cell.
+      */
+      nCell = pCell[0];
+      if( nCell<=pPage->max1bytePayload ){
+        /* This branch runs if the record-size field of the cell is a
+        ** single byte varint and the record fits entirely on the main
+        ** b-tree page.  */
+        testcase( pCell+nCell+1==pPage->aDataEnd );
+        c = xRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
+      }else if( !(pCell[1] & 0x80)
+        && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
+      ){
+        /* The record-size field is a 2 byte varint and the record
+        ** fits entirely on the main b-tree page.  */
+        testcase( pCell+nCell+2==pPage->aDataEnd );
+        c = xRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
+      }else{
+        /* The record flows over onto one or more overflow pages. In
+        ** this case the whole cell needs to be parsed, a buffer allocated
+        ** and accessPayload() used to retrieve the record into the
+        ** buffer before VdbeRecordCompare() can be called.
+        **
+        ** If the record is corrupt, the xRecordCompare routine may read
+        ** up to two varints past the end of the buffer. An extra 18
+        ** bytes of padding is allocated at the end of the buffer in
+        ** case this happens.  */
+        void *pCellKey;
+        u8 * const pCellBody = pCell - pPage->childPtrSize;
+        const int nOverrun = 18;  /* Size of the overrun padding */
+        pPage->xParseCell(pPage, pCellBody, &pCur->info);
+        nCell = (int)pCur->info.nKey;
+        testcase( nCell<0 );   /* True if key size is 2^32 or more */
+        testcase( nCell==0 );  /* Invalid key size:  0x80 0x80 0x00 */
+        testcase( nCell==1 );  /* Invalid key size:  0x80 0x80 0x01 */
+        testcase( nCell==2 );  /* Minimum legal index key size */
+        if( nCell<2 || nCell/pCur->pBt->usableSize>pCur->pBt->nPage ){
+          rc = SQLITE_CORRUPT_PAGE(pPage);
+          goto moveto_index_finish;
+        }
+        pCellKey = sqlite3Malloc( nCell+nOverrun );
+        if( pCellKey==0 ){
+          rc = SQLITE_NOMEM_BKPT;
+          goto moveto_index_finish;
+        }
+        pCur->ix = (u16)idx;
+        rc = accessPayload(pCur, 0, nCell, (unsigned char*)pCellKey, 0);
+        memset(((u8*)pCellKey)+nCell,0,nOverrun); /* Fix uninit warnings */
+        pCur->curFlags &= ~BTCF_ValidOvfl;
+        if( rc ){
+          sqlite3_free(pCellKey);
+          goto moveto_index_finish;
+        }
+        c = sqlite3VdbeRecordCompare(nCell, pCellKey, pIdxKey);
+        sqlite3_free(pCellKey);
+      }
+      assert(
+          (pIdxKey->errCode!=SQLITE_CORRUPT || c==0)
+       && (pIdxKey->errCode!=SQLITE_NOMEM || pCur->pBtree->db->mallocFailed)
+      );
+      if( c<0 ){
+        lwr = idx+1;
+      }else if( c>0 ){
+        upr = idx-1;
+      }else{
+        assert( c==0 );
+        *pRes = 0;
+        rc = SQLITE_OK;
+        pCur->ix = (u16)idx;
+        if( pIdxKey->errCode ) rc = SQLITE_CORRUPT_BKPT;
+        goto moveto_index_finish;
+      }
+      if( lwr>upr ) break;
+      assert( lwr+upr>=0 );
+      idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2 */
+    }
+    assert( lwr==upr+1 || (pPage->intKey && !pPage->leaf) );
+    assert( pPage->isInit );
+    if( pPage->leaf ){
+      assert( pCur->ix<pCur->pPage->nCell || CORRUPT_DB );
+      pCur->ix = (u16)idx;
+      *pRes = c;
+      rc = SQLITE_OK;
+      goto moveto_index_finish;
+    }
+    if( lwr>=pPage->nCell ){
+      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    }else{
+      chldPg = get4byte(findCell(pPage, lwr));
+    }
+
+    /* This block is similar to an in-lined version of:
+    **
+    **    pCur->ix = (u16)lwr;
+    **    rc = moveToChild(pCur, chldPg);
+    **    if( rc ) break;
+    */
+    pCur->info.nSize = 0;
+    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+    if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+    pCur->aiIdx[pCur->iPage] = (u16)lwr;
+    pCur->apPage[pCur->iPage] = pCur->pPage;
+    pCur->ix = 0;
+    pCur->iPage++;
+    rc = getAndInitPage(pCur->pBt, chldPg, &pCur->pPage, pCur->curPagerFlags);
+    if( rc==SQLITE_OK
+     && (pCur->pPage->nCell<1 || pCur->pPage->intKey!=pCur->curIntKey)
+    ){
+      releasePage(pCur->pPage);
+      rc = SQLITE_CORRUPT_PGNO(chldPg);
+    }
+    if( rc ){
+      pCur->pPage = pCur->apPage[--pCur->iPage];
+      break;
+    }
+    /*
+    ***** End of in-lined moveToChild() call */
+ }
+moveto_index_finish:
+  pCur->info.nSize = 0;
+  assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
+  return rc;
+}
+
+
+/*
+** Return TRUE if the cursor is not pointing at an entry of the table.
+**
+** TRUE will be returned after a call to sqlite3BtreeNext() moves
+** past the last entry in the table or sqlite3BtreePrev() moves past
+** the first entry.  TRUE is also returned if the table is empty.
+*/
+SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor *pCur){
+  /* TODO: What if the cursor is in CURSOR_REQUIRESEEK but all table entries
+  ** have been deleted? This API will need to change to return an error code
+  ** as well as the boolean result value.
+  */
+  return (CURSOR_VALID!=pCur->eState);
+}
+
+/*
+** Return an estimate for the number of rows in the table that pCur is
+** pointing to.  Return a negative number if no estimate is currently
+** available.
+*/
+SQLITE_PRIVATE i64 sqlite3BtreeRowCountEst(BtCursor *pCur){
+  i64 n;
+  u8 i;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+
+  /* Currently this interface is only called by the OP_IfSizeBetween
+  ** opcode and the OP_Count opcode with P3=1.  In either case,
+  ** the cursor will always be valid unless the btree is empty. */
+  if( pCur->eState!=CURSOR_VALID ) return 0;
+  if( NEVER(pCur->pPage->leaf==0) ) return -1;
+
+  n = pCur->pPage->nCell;
+  for(i=0; i<pCur->iPage; i++){
+    n *= pCur->apPage[i]->nCell;
+  }
+  return n;
+}
+
+/*
+** Advance the cursor to the next entry in the database.
+** Return value:
+**
+**    SQLITE_OK        success
+**    SQLITE_DONE      cursor is already pointing at the last element
+**    otherwise        some kind of error occurred
+**
+** The main entry point is sqlite3BtreeNext().  That routine is optimized
+** for the common case of merely incrementing the cell counter BtCursor.aiIdx
+** to the next cell on the current page.  The (slower) btreeNext() helper
+** routine is called when it is necessary to move to a different page or
+** to restore the cursor.
+**
+** If bit 0x01 of the F argument in sqlite3BtreeNext(C,F) is 1, then the
+** cursor corresponds to an SQL index and this routine could have been
+** skipped if the SQL index had been a unique index.  The F argument
+** is a hint to the implement.  SQLite btree implementation does not use
+** this hint, but COMDB2 does.
+*/
+static SQLITE_NOINLINE int btreeNext(BtCursor *pCur){
+  int rc;
+  int idx;
+  MemPage *pPage;
+
+  assert( cursorOwnsBtShared(pCur) );
+  if( pCur->eState!=CURSOR_VALID ){
+    assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
+    rc = restoreCursorPosition(pCur);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( CURSOR_INVALID==pCur->eState ){
+      return SQLITE_DONE;
+    }
+    if( pCur->eState==CURSOR_SKIPNEXT ){
+      pCur->eState = CURSOR_VALID;
+      if( pCur->skipNext>0 ) return SQLITE_OK;
+    }
+  }
+
+  pPage = pCur->pPage;
+  idx = ++pCur->ix;
+  if( sqlite3FaultSim(412) ) pPage->isInit = 0;
+  if( !pPage->isInit ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+
+  if( idx>=pPage->nCell ){
+    if( !pPage->leaf ){
+      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
+      if( rc ) return rc;
+      return moveToLeftmost(pCur);
+    }
+    do{
+      if( pCur->iPage==0 ){
+        pCur->eState = CURSOR_INVALID;
+        return SQLITE_DONE;
+      }
+      moveToParent(pCur);
+      pPage = pCur->pPage;
+    }while( pCur->ix>=pPage->nCell );
+    if( pPage->intKey ){
+      return sqlite3BtreeNext(pCur, 0);
+    }else{
+      return SQLITE_OK;
+    }
+  }
+  if( pPage->leaf ){
+    return SQLITE_OK;
+  }else{
+    return moveToLeftmost(pCur);
+  }
+}
+SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor *pCur, int flags){
+  MemPage *pPage;
+  UNUSED_PARAMETER( flags );  /* Used in COMDB2 but not native SQLite */
+  assert( cursorOwnsBtShared(pCur) );
+  assert( flags==0 || flags==1 );
+  pCur->info.nSize = 0;
+  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+  if( pCur->eState!=CURSOR_VALID ) return btreeNext(pCur);
+  pPage = pCur->pPage;
+  if( (++pCur->ix)>=pPage->nCell ){
+    pCur->ix--;
+    return btreeNext(pCur);
+  }
+  if( pPage->leaf ){
+    return SQLITE_OK;
+  }else{
+    return moveToLeftmost(pCur);
+  }
+}
+
+/*
+** Step the cursor to the back to the previous entry in the database.
+** Return values:
+**
+**     SQLITE_OK     success
+**     SQLITE_DONE   the cursor is already on the first element of the table
+**     otherwise     some kind of error occurred
+**
+** The main entry point is sqlite3BtreePrevious().  That routine is optimized
+** for the common case of merely decrementing the cell counter BtCursor.aiIdx
+** to the previous cell on the current page.  The (slower) btreePrevious()
+** helper routine is called when it is necessary to move to a different page
+** or to restore the cursor.
+**
+** If bit 0x01 of the F argument to sqlite3BtreePrevious(C,F) is 1, then
+** the cursor corresponds to an SQL index and this routine could have been
+** skipped if the SQL index had been a unique index.  The F argument is a
+** hint to the implement.  The native SQLite btree implementation does not
+** use this hint, but COMDB2 does.
+*/
+static SQLITE_NOINLINE int btreePrevious(BtCursor *pCur){
+  int rc;
+  MemPage *pPage;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( (pCur->curFlags & (BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey))==0 );
+  assert( pCur->info.nSize==0 );
+  if( pCur->eState!=CURSOR_VALID ){
+    rc = restoreCursorPosition(pCur);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( CURSOR_INVALID==pCur->eState ){
+      return SQLITE_DONE;
+    }
+    if( CURSOR_SKIPNEXT==pCur->eState ){
+      pCur->eState = CURSOR_VALID;
+      if( pCur->skipNext<0 ) return SQLITE_OK;
+    }
+  }
+
+  pPage = pCur->pPage;
+  if( sqlite3FaultSim(412) ) pPage->isInit = 0;
+  if( !pPage->isInit ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( !pPage->leaf ){
+    int idx = pCur->ix;
+    rc = moveToChild(pCur, get4byte(findCell(pPage, idx)));
+    if( rc ) return rc;
+    rc = moveToRightmost(pCur);
+  }else{
+    while( pCur->ix==0 ){
+      if( pCur->iPage==0 ){
+        pCur->eState = CURSOR_INVALID;
+        return SQLITE_DONE;
+      }
+      moveToParent(pCur);
+    }
+    assert( pCur->info.nSize==0 );
+    assert( (pCur->curFlags & (BTCF_ValidOvfl))==0 );
+
+    pCur->ix--;
+    pPage = pCur->pPage;
+    if( pPage->intKey && !pPage->leaf ){
+      rc = sqlite3BtreePrevious(pCur, 0);
+    }else{
+      rc = SQLITE_OK;
+    }
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor *pCur, int flags){
+  assert( cursorOwnsBtShared(pCur) );
+  assert( flags==0 || flags==1 );
+  UNUSED_PARAMETER( flags );  /* Used in COMDB2 but not native SQLite */
+  pCur->curFlags &= ~(BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey);
+  pCur->info.nSize = 0;
+  if( pCur->eState!=CURSOR_VALID
+   || pCur->ix==0
+   || pCur->pPage->leaf==0
+  ){
+    return btreePrevious(pCur);
+  }
+  pCur->ix--;
+  return SQLITE_OK;
+}
+
+/*
+** Allocate a new page from the database file.
+**
+** The new page is marked as dirty.  (In other words, sqlite3PagerWrite()
+** has already been called on the new page.)  The new page has also
+** been referenced and the calling routine is responsible for calling
+** sqlite3PagerUnref() on the new page when it is done.
+**
+** SQLITE_OK is returned on success.  Any other return value indicates
+** an error.  *ppPage is set to NULL in the event of an error.
+**
+** If the "nearby" parameter is not 0, then an effort is made to
+** locate a page close to the page number "nearby".  This can be used in an
+** attempt to keep related pages close to each other in the database file,
+** which in turn can make database access faster.
+**
+** If the eMode parameter is BTALLOC_EXACT and the nearby page exists
+** anywhere on the free-list, then it is guaranteed to be returned.  If
+** eMode is BTALLOC_LT then the page returned will be less than or equal
+** to nearby if any such page exists.  If eMode is BTALLOC_ANY then there
+** are no restrictions on which page is returned.
+*/
+static int allocateBtreePage(
+  BtShared *pBt,         /* The btree */
+  MemPage **ppPage,      /* Store pointer to the allocated page here */
+  Pgno *pPgno,           /* Store the page number here */
+  Pgno nearby,           /* Search for a page near this one */
+  u8 eMode               /* BTALLOC_EXACT, BTALLOC_LT, or BTALLOC_ANY */
+){
+  MemPage *pPage1;
+  int rc;
+  u32 n;     /* Number of pages on the freelist */
+  u32 k;     /* Number of leaves on the trunk of the freelist */
+  MemPage *pTrunk = 0;
+  MemPage *pPrevTrunk = 0;
+  Pgno mxPage;     /* Total size of the database file */
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( eMode==BTALLOC_ANY || (nearby>0 && IfNotOmitAV(pBt->autoVacuum)) );
+  pPage1 = pBt->pPage1;
+  mxPage = btreePagecount(pBt);
+  /* EVIDENCE-OF: R-21003-45125 The 4-byte big-endian integer at offset 36
+  ** stores the total number of pages on the freelist. */
+  n = get4byte(&pPage1->aData[36]);
+  testcase( n==mxPage-1 );
+  if( n>=mxPage ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( n>0 ){
+    /* There are pages on the freelist.  Reuse one of those pages. */
+    Pgno iTrunk;
+    u8 searchList = 0; /* If the free-list must be searched for 'nearby' */
+    u32 nSearch = 0;   /* Count of the number of search attempts */
+
+    /* If eMode==BTALLOC_EXACT and a query of the pointer-map
+    ** shows that the page 'nearby' is somewhere on the free-list, then
+    ** the entire-list will be searched for that page.
+    */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( eMode==BTALLOC_EXACT ){
+      if( nearby<=mxPage ){
+        u8 eType;
+        assert( nearby>0 );
+        assert( pBt->autoVacuum );
+        rc = ptrmapGet(pBt, nearby, &eType, 0);
+        if( rc ) return rc;
+        if( eType==PTRMAP_FREEPAGE ){
+          searchList = 1;
+        }
+      }
+    }else if( eMode==BTALLOC_LE ){
+      searchList = 1;
+    }
+#endif
+
+    /* Decrement the free-list count by 1. Set iTrunk to the index of the
+    ** first free-list trunk page. iPrevTrunk is initially 1.
+    */
+    rc = sqlite3PagerWrite(pPage1->pDbPage);
+    if( rc ) return rc;
+    put4byte(&pPage1->aData[36], n-1);
+
+    /* The code within this loop is run only once if the 'searchList' variable
+    ** is not true. Otherwise, it runs once for each trunk-page on the
+    ** free-list until the page 'nearby' is located (eMode==BTALLOC_EXACT)
+    ** or until a page less than 'nearby' is located (eMode==BTALLOC_LT)
+    */
+    do {
+      pPrevTrunk = pTrunk;
+      if( pPrevTrunk ){
+        /* EVIDENCE-OF: R-01506-11053 The first integer on a freelist trunk page
+        ** is the page number of the next freelist trunk page in the list or
+        ** zero if this is the last freelist trunk page. */
+        iTrunk = get4byte(&pPrevTrunk->aData[0]);
+      }else{
+        /* EVIDENCE-OF: R-59841-13798 The 4-byte big-endian integer at offset 32
+        ** stores the page number of the first page of the freelist, or zero if
+        ** the freelist is empty. */
+        iTrunk = get4byte(&pPage1->aData[32]);
+      }
+      testcase( iTrunk==mxPage );
+      if( iTrunk>mxPage || nSearch++ > n ){
+        rc = SQLITE_CORRUPT_PGNO(pPrevTrunk ? pPrevTrunk->pgno : 1);
+      }else{
+        rc = btreeGetUnusedPage(pBt, iTrunk, &pTrunk, 0);
+      }
+      if( rc ){
+        pTrunk = 0;
+        goto end_allocate_page;
+      }
+      assert( pTrunk!=0 );
+      assert( pTrunk->aData!=0 );
+      /* EVIDENCE-OF: R-13523-04394 The second integer on a freelist trunk page
+      ** is the number of leaf page pointers to follow. */
+      k = get4byte(&pTrunk->aData[4]);
+      if( k==0 && !searchList ){
+        /* The trunk has no leaves and the list is not being searched.
+        ** So extract the trunk page itself and use it as the newly
+        ** allocated page */
+        assert( pPrevTrunk==0 );
+        rc = sqlite3PagerWrite(pTrunk->pDbPage);
+        if( rc ){
+          goto end_allocate_page;
+        }
+        *pPgno = iTrunk;
+        memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
+        *ppPage = pTrunk;
+        pTrunk = 0;
+        TRACE(("ALLOCATE: %u trunk - %u free pages left\n", *pPgno, n-1));
+      }else if( k>(u32)(pBt->usableSize/4 - 2) ){
+        /* Value of k is out of range.  Database corruption */
+        rc = SQLITE_CORRUPT_PGNO(iTrunk);
+        goto end_allocate_page;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      }else if( searchList
+            && (nearby==iTrunk || (iTrunk<nearby && eMode==BTALLOC_LE))
+      ){
+        /* The list is being searched and this trunk page is the page
+        ** to allocate, regardless of whether it has leaves.
+        */
+        *pPgno = iTrunk;
+        *ppPage = pTrunk;
+        searchList = 0;
+        rc = sqlite3PagerWrite(pTrunk->pDbPage);
+        if( rc ){
+          goto end_allocate_page;
+        }
+        if( k==0 ){
+          if( !pPrevTrunk ){
+            memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
+          }else{
+            rc = sqlite3PagerWrite(pPrevTrunk->pDbPage);
+            if( rc!=SQLITE_OK ){
+              goto end_allocate_page;
+            }
+            memcpy(&pPrevTrunk->aData[0], &pTrunk->aData[0], 4);
+          }
+        }else{
+          /* The trunk page is required by the caller but it contains
+          ** pointers to free-list leaves. The first leaf becomes a trunk
+          ** page in this case.
+          */
+          MemPage *pNewTrunk;
+          Pgno iNewTrunk = get4byte(&pTrunk->aData[8]);
+          if( iNewTrunk>mxPage ){
+            rc = SQLITE_CORRUPT_PGNO(iTrunk);
+            goto end_allocate_page;
+          }
+          testcase( iNewTrunk==mxPage );
+          rc = btreeGetUnusedPage(pBt, iNewTrunk, &pNewTrunk, 0);
+          if( rc!=SQLITE_OK ){
+            goto end_allocate_page;
+          }
+          rc = sqlite3PagerWrite(pNewTrunk->pDbPage);
+          if( rc!=SQLITE_OK ){
+            releasePage(pNewTrunk);
+            goto end_allocate_page;
+          }
+          memcpy(&pNewTrunk->aData[0], &pTrunk->aData[0], 4);
+          put4byte(&pNewTrunk->aData[4], k-1);
+          memcpy(&pNewTrunk->aData[8], &pTrunk->aData[12], (k-1)*4);
+          releasePage(pNewTrunk);
+          if( !pPrevTrunk ){
+            assert( sqlite3PagerIswriteable(pPage1->pDbPage) );
+            put4byte(&pPage1->aData[32], iNewTrunk);
+          }else{
+            rc = sqlite3PagerWrite(pPrevTrunk->pDbPage);
+            if( rc ){
+              goto end_allocate_page;
+            }
+            put4byte(&pPrevTrunk->aData[0], iNewTrunk);
+          }
+        }
+        pTrunk = 0;
+        TRACE(("ALLOCATE: %u trunk - %u free pages left\n", *pPgno, n-1));
+#endif
+      }else if( k>0 ){
+        /* Extract a leaf from the trunk */
+        u32 closest;
+        Pgno iPage;
+        unsigned char *aData = pTrunk->aData;
+        if( nearby>0 ){
+          u32 i;
+          closest = 0;
+          if( eMode==BTALLOC_LE ){
+            for(i=0; i<k; i++){
+              iPage = get4byte(&aData[8+i*4]);
+              if( iPage<=nearby ){
+                closest = i;
+                break;
+              }
+            }
+          }else{
+            int dist;
+            dist = sqlite3AbsInt32(get4byte(&aData[8]) - nearby);
+            for(i=1; i<k; i++){
+              int d2 = sqlite3AbsInt32(get4byte(&aData[8+i*4]) - nearby);
+              if( d2<dist ){
+                closest = i;
+                dist = d2;
+              }
+            }
+          }
+        }else{
+          closest = 0;
+        }
+
+        iPage = get4byte(&aData[8+closest*4]);
+        testcase( iPage==mxPage );
+        if( iPage>mxPage || iPage<2 ){
+          rc = SQLITE_CORRUPT_PGNO(iTrunk);
+          goto end_allocate_page;
+        }
+        testcase( iPage==mxPage );
+        if( !searchList
+         || (iPage==nearby || (iPage<nearby && eMode==BTALLOC_LE))
+        ){
+          int noContent;
+          *pPgno = iPage;
+          TRACE(("ALLOCATE: %u was leaf %u of %u on trunk %u"
+                 ": %u more free pages\n",
+                 *pPgno, closest+1, k, pTrunk->pgno, n-1));
+          rc = sqlite3PagerWrite(pTrunk->pDbPage);
+          if( rc ) goto end_allocate_page;
+          if( closest<k-1 ){
+            memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
+          }
+          put4byte(&aData[4], k-1);
+          noContent = !btreeGetHasContent(pBt, *pPgno)? PAGER_GET_NOCONTENT : 0;
+          rc = btreeGetUnusedPage(pBt, *pPgno, ppPage, noContent);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3PagerWrite((*ppPage)->pDbPage);
+            if( rc!=SQLITE_OK ){
+              releasePage(*ppPage);
+              *ppPage = 0;
+            }
+          }
+          searchList = 0;
+        }
+      }
+      releasePage(pPrevTrunk);
+      pPrevTrunk = 0;
+    }while( searchList );
+  }else{
+    /* There are no pages on the freelist, so append a new page to the
+    ** database image.
+    **
+    ** Normally, new pages allocated by this block can be requested from the
+    ** pager layer with the 'no-content' flag set. This prevents the pager
+    ** from trying to read the pages content from disk. However, if the
+    ** current transaction has already run one or more incremental-vacuum
+    ** steps, then the page we are about to allocate may contain content
+    ** that is required in the event of a rollback. In this case, do
+    ** not set the no-content flag. This causes the pager to load and journal
+    ** the current page content before overwriting it.
+    **
+    ** Note that the pager will not actually attempt to load or journal
+    ** content for any page that really does lie past the end of the database
+    ** file on disk. So the effects of disabling the no-content optimization
+    ** here are confined to those pages that lie between the end of the
+    ** database image and the end of the database file.
+    */
+    int bNoContent = (0==IfNotOmitAV(pBt->bDoTruncate))? PAGER_GET_NOCONTENT:0;
+
+    rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+    if( rc ) return rc;
+    pBt->nPage++;
+    if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ) pBt->nPage++;
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum && PTRMAP_ISPAGE(pBt, pBt->nPage) ){
+      /* If *pPgno refers to a pointer-map page, allocate two new pages
+      ** at the end of the file instead of one. The first allocated page
+      ** becomes a new pointer-map page, the second is used by the caller.
+      */
+      MemPage *pPg = 0;
+      TRACE(("ALLOCATE: %u from end of file (pointer-map page)\n", pBt->nPage));
+      assert( pBt->nPage!=PENDING_BYTE_PAGE(pBt) );
+      rc = btreeGetUnusedPage(pBt, pBt->nPage, &pPg, bNoContent);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pPg->pDbPage);
+        releasePage(pPg);
+      }
+      if( rc ) return rc;
+      pBt->nPage++;
+      if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ){ pBt->nPage++; }
+    }
+#endif
+    put4byte(28 + (u8*)pBt->pPage1->aData, pBt->nPage);
+    *pPgno = pBt->nPage;
+
+    assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
+    rc = btreeGetUnusedPage(pBt, *pPgno, ppPage, bNoContent);
+    if( rc ) return rc;
+    rc = sqlite3PagerWrite((*ppPage)->pDbPage);
+    if( rc!=SQLITE_OK ){
+      releasePage(*ppPage);
+      *ppPage = 0;
+    }
+    TRACE(("ALLOCATE: %u from end of file\n", *pPgno));
+  }
+
+  assert( CORRUPT_DB || *pPgno!=PENDING_BYTE_PAGE(pBt) );
+
+end_allocate_page:
+  releasePage(pTrunk);
+  releasePage(pPrevTrunk);
+  assert( rc!=SQLITE_OK || sqlite3PagerPageRefcount((*ppPage)->pDbPage)<=1 );
+  assert( rc!=SQLITE_OK || (*ppPage)->isInit==0 );
+  return rc;
+}
+
+/*
+** This function is used to add page iPage to the database file free-list.
+** It is assumed that the page is not already a part of the free-list.
+**
+** The value passed as the second argument to this function is optional.
+** If the caller happens to have a pointer to the MemPage object
+** corresponding to page iPage handy, it may pass it as the second value.
+** Otherwise, it may pass NULL.
+**
+** If a pointer to a MemPage object is passed as the second argument,
+** its reference count is not altered by this function.
+*/
+static int freePage2(BtShared *pBt, MemPage *pMemPage, Pgno iPage){
+  MemPage *pTrunk = 0;                /* Free-list trunk page */
+  Pgno iTrunk = 0;                    /* Page number of free-list trunk page */
+  MemPage *pPage1 = pBt->pPage1;      /* Local reference to page 1 */
+  MemPage *pPage;                     /* Page being freed. May be NULL. */
+  int rc;                             /* Return Code */
+  u32 nFree;                          /* Initial number of pages on free-list */
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( CORRUPT_DB || iPage>1 );
+  assert( !pMemPage || pMemPage->pgno==iPage );
+
+  if( iPage<2 || iPage>pBt->nPage ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( pMemPage ){
+    pPage = pMemPage;
+    sqlite3PagerRef(pPage->pDbPage);
+  }else{
+    pPage = btreePageLookup(pBt, iPage);
+  }
+
+  /* Increment the free page count on pPage1 */
+  rc = sqlite3PagerWrite(pPage1->pDbPage);
+  if( rc ) goto freepage_out;
+  nFree = get4byte(&pPage1->aData[36]);
+  put4byte(&pPage1->aData[36], nFree+1);
+
+  if( pBt->btsFlags & BTS_SECURE_DELETE ){
+    /* If the secure_delete option is enabled, then
+    ** always fully overwrite deleted information with zeros.
+    */
+    if( (!pPage && ((rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0) )
+     ||            ((rc = sqlite3PagerWrite(pPage->pDbPage))!=0)
+    ){
+      goto freepage_out;
+    }
+    memset(pPage->aData, 0, pPage->pBt->pageSize);
+  }
+
+  /* If the database supports auto-vacuum, write an entry in the pointer-map
+  ** to indicate that the page is free.
+  */
+  if( ISAUTOVACUUM(pBt) ){
+    ptrmapPut(pBt, iPage, PTRMAP_FREEPAGE, 0, &rc);
+    if( rc ) goto freepage_out;
+  }
+
+  /* Now manipulate the actual database free-list structure. There are two
+  ** possibilities. If the free-list is currently empty, or if the first
+  ** trunk page in the free-list is full, then this page will become a
+  ** new free-list trunk page. Otherwise, it will become a leaf of the
+  ** first trunk page in the current free-list. This block tests if it
+  ** is possible to add the page as a new free-list leaf.
+  */
+  if( nFree!=0 ){
+    u32 nLeaf;                /* Initial number of leaf cells on trunk page */
+
+    iTrunk = get4byte(&pPage1->aData[32]);
+    if( iTrunk>btreePagecount(pBt) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto freepage_out;
+    }
+    rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
+    if( rc!=SQLITE_OK ){
+      goto freepage_out;
+    }
+
+    nLeaf = get4byte(&pTrunk->aData[4]);
+    assert( pBt->usableSize>32 );
+    if( nLeaf > (u32)pBt->usableSize/4 - 2 ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto freepage_out;
+    }
+    if( nLeaf < (u32)pBt->usableSize/4 - 8 ){
+      /* In this case there is room on the trunk page to insert the page
+      ** being freed as a new leaf.
+      **
+      ** Note that the trunk page is not really full until it contains
+      ** usableSize/4 - 2 entries, not usableSize/4 - 8 entries as we have
+      ** coded.  But due to a coding error in versions of SQLite prior to
+      ** 3.6.0, databases with freelist trunk pages holding more than
+      ** usableSize/4 - 8 entries will be reported as corrupt.  In order
+      ** to maintain backwards compatibility with older versions of SQLite,
+      ** we will continue to restrict the number of entries to usableSize/4 - 8
+      ** for now.  At some point in the future (once everyone has upgraded
+      ** to 3.6.0 or later) we should consider fixing the conditional above
+      ** to read "usableSize/4-2" instead of "usableSize/4-8".
+      **
+      ** EVIDENCE-OF: R-19920-11576 However, newer versions of SQLite still
+      ** avoid using the last six entries in the freelist trunk page array in
+      ** order that database files created by newer versions of SQLite can be
+      ** read by older versions of SQLite.
+      */
+      rc = sqlite3PagerWrite(pTrunk->pDbPage);
+      if( rc==SQLITE_OK ){
+        put4byte(&pTrunk->aData[4], nLeaf+1);
+        put4byte(&pTrunk->aData[8+nLeaf*4], iPage);
+        if( pPage && (pBt->btsFlags & BTS_SECURE_DELETE)==0 ){
+          sqlite3PagerDontWrite(pPage->pDbPage);
+        }
+        rc = btreeSetHasContent(pBt, iPage);
+      }
+      TRACE(("FREE-PAGE: %u leaf on trunk page %u\n",pPage->pgno,pTrunk->pgno));
+      goto freepage_out;
+    }
+  }
+
+  /* If control flows to this point, then it was not possible to add the
+  ** the page being freed as a leaf page of the first trunk in the free-list.
+  ** Possibly because the free-list is empty, or possibly because the
+  ** first trunk in the free-list is full. Either way, the page being freed
+  ** will become the new first trunk page in the free-list.
+  */
+  if( pPage==0 && SQLITE_OK!=(rc = btreeGetPage(pBt, iPage, &pPage, 0)) ){
+    goto freepage_out;
+  }
+  rc = sqlite3PagerWrite(pPage->pDbPage);
+  if( rc!=SQLITE_OK ){
+    goto freepage_out;
+  }
+  put4byte(pPage->aData, iTrunk);
+  put4byte(&pPage->aData[4], 0);
+  put4byte(&pPage1->aData[32], iPage);
+  TRACE(("FREE-PAGE: %u new trunk page replacing %u\n", pPage->pgno, iTrunk));
+
+freepage_out:
+  if( pPage ){
+    pPage->isInit = 0;
+  }
+  releasePage(pPage);
+  releasePage(pTrunk);
+  return rc;
+}
+static void freePage(MemPage *pPage, int *pRC){
+  if( (*pRC)==SQLITE_OK ){
+    *pRC = freePage2(pPage->pBt, pPage, pPage->pgno);
+  }
+}
+
+/*
+** Free the overflow pages associated with the given Cell.
+*/
+static SQLITE_NOINLINE int clearCellOverflow(
+  MemPage *pPage,          /* The page that contains the Cell */
+  unsigned char *pCell,    /* First byte of the Cell */
+  CellInfo *pInfo          /* Size information about the cell */
+){
+  BtShared *pBt;
+  Pgno ovflPgno;
+  int rc;
+  int nOvfl;
+  u32 ovflPageSize;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pInfo->nLocal!=pInfo->nPayload );
+  testcase( pCell + pInfo->nSize == pPage->aDataEnd );
+  testcase( pCell + (pInfo->nSize-1) == pPage->aDataEnd );
+  if( pCell + pInfo->nSize > pPage->aDataEnd ){
+    /* Cell extends past end of page */
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  ovflPgno = get4byte(pCell + pInfo->nSize - 4);
+  pBt = pPage->pBt;
+  assert( pBt->usableSize > 4 );
+  ovflPageSize = pBt->usableSize - 4;
+  nOvfl = (pInfo->nPayload - pInfo->nLocal + ovflPageSize - 1)/ovflPageSize;
+  assert( nOvfl>0 ||
+    (CORRUPT_DB && (pInfo->nPayload + ovflPageSize)<ovflPageSize)
+  );
+  while( nOvfl-- ){
+    Pgno iNext = 0;
+    MemPage *pOvfl = 0;
+    if( ovflPgno<2 || ovflPgno>btreePagecount(pBt) ){
+      /* 0 is not a legal page number and page 1 cannot be an
+      ** overflow page. Therefore if ovflPgno<2 or past the end of the
+      ** file the database must be corrupt. */
+      return SQLITE_CORRUPT_BKPT;
+    }
+    if( nOvfl ){
+      rc = getOverflowPage(pBt, ovflPgno, &pOvfl, &iNext);
+      if( rc ) return rc;
+    }
+
+    if( ( pOvfl || ((pOvfl = btreePageLookup(pBt, ovflPgno))!=0) )
+     && sqlite3PagerPageRefcount(pOvfl->pDbPage)!=1
+    ){
+      /* There is no reason any cursor should have an outstanding reference
+      ** to an overflow page belonging to a cell that is being deleted/updated.
+      ** So if there exists more than one reference to this page, then it
+      ** must not really be an overflow page and the database must be corrupt.
+      ** It is helpful to detect this before calling freePage2(), as
+      ** freePage2() may zero the page contents if secure-delete mode is
+      ** enabled. If this 'overflow' page happens to be a page that the
+      ** caller is iterating through or using in some other way, this
+      ** can be problematic.
+      */
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      rc = freePage2(pBt, pOvfl, ovflPgno);
+    }
+
+    if( pOvfl ){
+      sqlite3PagerUnref(pOvfl->pDbPage);
+    }
+    if( rc ) return rc;
+    ovflPgno = iNext;
+  }
+  return SQLITE_OK;
+}
+
+/* Call xParseCell to compute the size of a cell.  If the cell contains
+** overflow, then invoke cellClearOverflow to clear out that overflow.
+** Store the result code (SQLITE_OK or some error code) in rc.
+**
+** Implemented as macro to force inlining for performance.
+*/
+#define BTREE_CLEAR_CELL(rc, pPage, pCell, sInfo)   \
+  pPage->xParseCell(pPage, pCell, &sInfo);          \
+  if( sInfo.nLocal!=sInfo.nPayload ){               \
+    rc = clearCellOverflow(pPage, pCell, &sInfo);   \
+  }else{                                            \
+    rc = SQLITE_OK;                                 \
+  }
+
+
+/*
+** Create the byte sequence used to represent a cell on page pPage
+** and write that byte sequence into pCell[].  Overflow pages are
+** allocated and filled in as necessary.  The calling procedure
+** is responsible for making sure sufficient space has been allocated
+** for pCell[].
+**
+** Note that pCell does not necessary need to point to the pPage->aData
+** area.  pCell might point to some temporary storage.  The cell will
+** be constructed in this temporary area then copied into pPage->aData
+** later.
+*/
+static int fillInCell(
+  MemPage *pPage,                /* The page that contains the cell */
+  unsigned char *pCell,          /* Complete text of the cell */
+  const BtreePayload *pX,        /* Payload with which to construct the cell */
+  int *pnSize                    /* Write cell size here */
+){
+  int nPayload;
+  const u8 *pSrc;
+  int nSrc, n, rc, mn;
+  int spaceLeft;
+  MemPage *pToRelease;
+  unsigned char *pPrior;
+  unsigned char *pPayload;
+  BtShared *pBt;
+  Pgno pgnoOvfl;
+  int nHeader;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+
+  /* pPage is not necessarily writeable since pCell might be auxiliary
+  ** buffer space that is separate from the pPage buffer area */
+  assert( pCell<pPage->aData || pCell>=&pPage->aData[pPage->pBt->pageSize]
+            || sqlite3PagerIswriteable(pPage->pDbPage) );
+
+  /* Fill in the header. */
+  nHeader = pPage->childPtrSize;
+  if( pPage->intKey ){
+    nPayload = pX->nData + pX->nZero;
+    pSrc = pX->pData;
+    nSrc = pX->nData;
+    assert( pPage->intKeyLeaf ); /* fillInCell() only called for leaves */
+    nHeader += putVarint32(&pCell[nHeader], nPayload);
+    nHeader += putVarint(&pCell[nHeader], *(u64*)&pX->nKey);
+  }else{
+    assert( pX->nKey<=0x7fffffff && pX->pKey!=0 );
+    nSrc = nPayload = (int)pX->nKey;
+    pSrc = pX->pKey;
+    nHeader += putVarint32(&pCell[nHeader], nPayload);
+  }
+
+  /* Fill in the payload */
+  pPayload = &pCell[nHeader];
+  if( nPayload<=pPage->maxLocal ){
+    /* This is the common case where everything fits on the btree page
+    ** and no overflow pages are required. */
+    n = nHeader + nPayload;
+    testcase( n==3 );
+    testcase( n==4 );
+    if( n<4 ){
+      n = 4;
+      pPayload[nPayload] = 0;
+    }
+    *pnSize = n;
+    assert( nSrc<=nPayload );
+    testcase( nSrc<nPayload );
+    memcpy(pPayload, pSrc, nSrc);
+    memset(pPayload+nSrc, 0, nPayload-nSrc);
+    return SQLITE_OK;
+  }
+
+  /* If we reach this point, it means that some of the content will need
+  ** to spill onto overflow pages.
+  */
+  mn = pPage->minLocal;
+  n = mn + (nPayload - mn) % (pPage->pBt->usableSize - 4);
+  testcase( n==pPage->maxLocal );
+  testcase( n==pPage->maxLocal+1 );
+  if( n > pPage->maxLocal ) n = mn;
+  spaceLeft = n;
+  *pnSize = n + nHeader + 4;
+  pPrior = &pCell[nHeader+n];
+  pToRelease = 0;
+  pgnoOvfl = 0;
+  pBt = pPage->pBt;
+
+  /* At this point variables should be set as follows:
+  **
+  **   nPayload           Total payload size in bytes
+  **   pPayload           Begin writing payload here
+  **   spaceLeft          Space available at pPayload.  If nPayload>spaceLeft,
+  **                      that means content must spill into overflow pages.
+  **   *pnSize            Size of the local cell (not counting overflow pages)
+  **   pPrior             Where to write the pgno of the first overflow page
+  **
+  ** Use a call to btreeParseCellPtr() to verify that the values above
+  ** were computed correctly.
+  */
+#ifdef SQLITE_DEBUG
+  {
+    CellInfo info;
+    pPage->xParseCell(pPage, pCell, &info);
+    assert( nHeader==(int)(info.pPayload - pCell) );
+    assert( info.nKey==pX->nKey );
+    assert( *pnSize == info.nSize );
+    assert( spaceLeft == info.nLocal );
+  }
+#endif
+
+  /* Write the payload into the local Cell and any extra into overflow pages */
+  while( 1 ){
+    n = nPayload;
+    if( n>spaceLeft ) n = spaceLeft;
+
+    /* If pToRelease is not zero than pPayload points into the data area
+    ** of pToRelease.  Make sure pToRelease is still writeable. */
+    assert( pToRelease==0 || sqlite3PagerIswriteable(pToRelease->pDbPage) );
+
+    /* If pPayload is part of the data area of pPage, then make sure pPage
+    ** is still writeable */
+    assert( pPayload<pPage->aData || pPayload>=&pPage->aData[pBt->pageSize]
+            || sqlite3PagerIswriteable(pPage->pDbPage) );
+
+    if( nSrc>=n ){
+      memcpy(pPayload, pSrc, n);
+    }else if( nSrc>0 ){
+      n = nSrc;
+      memcpy(pPayload, pSrc, n);
+    }else{
+      memset(pPayload, 0, n);
+    }
+    nPayload -= n;
+    if( nPayload<=0 ) break;
+    pPayload += n;
+    pSrc += n;
+    nSrc -= n;
+    spaceLeft -= n;
+    if( spaceLeft==0 ){
+      MemPage *pOvfl = 0;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      Pgno pgnoPtrmap = pgnoOvfl; /* Overflow page pointer-map entry page */
+      if( pBt->autoVacuum ){
+        do{
+          pgnoOvfl++;
+        } while(
+          PTRMAP_ISPAGE(pBt, pgnoOvfl) || pgnoOvfl==PENDING_BYTE_PAGE(pBt)
+        );
+      }
+#endif
+      rc = allocateBtreePage(pBt, &pOvfl, &pgnoOvfl, pgnoOvfl, 0);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      /* If the database supports auto-vacuum, and the second or subsequent
+      ** overflow page is being allocated, add an entry to the pointer-map
+      ** for that page now.
+      **
+      ** If this is the first overflow page, then write a partial entry
+      ** to the pointer-map. If we write nothing to this pointer-map slot,
+      ** then the optimistic overflow chain processing in clearCell()
+      ** may misinterpret the uninitialized values and delete the
+      ** wrong pages from the database.
+      */
+      if( pBt->autoVacuum && rc==SQLITE_OK ){
+        u8 eType = (pgnoPtrmap?PTRMAP_OVERFLOW2:PTRMAP_OVERFLOW1);
+        ptrmapPut(pBt, pgnoOvfl, eType, pgnoPtrmap, &rc);
+        if( rc ){
+          releasePage(pOvfl);
+        }
+      }
+#endif
+      if( rc ){
+        releasePage(pToRelease);
+        return rc;
+      }
+
+      /* If pToRelease is not zero than pPrior points into the data area
+      ** of pToRelease.  Make sure pToRelease is still writeable. */
+      assert( pToRelease==0 || sqlite3PagerIswriteable(pToRelease->pDbPage) );
+
+      /* If pPrior is part of the data area of pPage, then make sure pPage
+      ** is still writeable */
+      assert( pPrior<pPage->aData || pPrior>=&pPage->aData[pBt->pageSize]
+            || sqlite3PagerIswriteable(pPage->pDbPage) );
+
+      put4byte(pPrior, pgnoOvfl);
+      releasePage(pToRelease);
+      pToRelease = pOvfl;
+      pPrior = pOvfl->aData;
+      put4byte(pPrior, 0);
+      pPayload = &pOvfl->aData[4];
+      spaceLeft = pBt->usableSize - 4;
+    }
+  }
+  releasePage(pToRelease);
+  return SQLITE_OK;
+}
+
+/*
+** Remove the i-th cell from pPage.  This routine effects pPage only.
+** The cell content is not freed or deallocated.  It is assumed that
+** the cell content has been copied someplace else.  This routine just
+** removes the reference to the cell from pPage.
+**
+** "sz" must be the number of bytes in the cell.
+*/
+static void dropCell(MemPage *pPage, int idx, int sz, int *pRC){
+  u32 pc;         /* Offset to cell content of cell being deleted */
+  u8 *data;       /* pPage->aData */
+  u8 *ptr;        /* Used to move bytes around within data[] */
+  int rc;         /* The return code */
+  int hdr;        /* Beginning of the header.  0 most pages.  100 page 1 */
+
+  if( *pRC ) return;
+  assert( idx>=0 );
+  assert( idx<pPage->nCell );
+  assert( CORRUPT_DB || sz==cellSize(pPage, idx) );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->nFree>=0 );
+  data = pPage->aData;
+  ptr = &pPage->aCellIdx[2*idx];
+  assert( pPage->pBt->usableSize > (u32)(ptr-data) );
+  pc = get2byte(ptr);
+  hdr = pPage->hdrOffset;
+  testcase( pc==(u32)get2byte(&data[hdr+5]) );
+  testcase( pc+sz==pPage->pBt->usableSize );
+  if( pc+sz > pPage->pBt->usableSize ){
+    *pRC = SQLITE_CORRUPT_BKPT;
+    return;
+  }
+  rc = freeSpace(pPage, pc, sz);
+  if( rc ){
+    *pRC = rc;
+    return;
+  }
+  pPage->nCell--;
+  if( pPage->nCell==0 ){
+    memset(&data[hdr+1], 0, 4);
+    data[hdr+7] = 0;
+    put2byte(&data[hdr+5], pPage->pBt->usableSize);
+    pPage->nFree = pPage->pBt->usableSize - pPage->hdrOffset
+                       - pPage->childPtrSize - 8;
+  }else{
+    memmove(ptr, ptr+2, 2*(pPage->nCell - idx));
+    put2byte(&data[hdr+3], pPage->nCell);
+    pPage->nFree += 2;
+  }
+}
+
+/*
+** Insert a new cell on pPage at cell index "i".  pCell points to the
+** content of the cell.
+**
+** If the cell content will fit on the page, then put it there.  If it
+** will not fit, then make a copy of the cell content into pTemp if
+** pTemp is not null.  Regardless of pTemp, allocate a new entry
+** in pPage->apOvfl[] and make it point to the cell content (either
+** in pTemp or the original pCell) and also record its index.
+** Allocating a new entry in pPage->aCell[] implies that
+** pPage->nOverflow is incremented.
+**
+** The insertCellFast() routine below works exactly the same as
+** insertCell() except that it lacks the pTemp and iChild parameters
+** which are assumed zero.  Other than that, the two routines are the
+** same.
+**
+** Fixes or enhancements to this routine should be reflected in
+** insertCellFast()!
+*/
+static int insertCell(
+  MemPage *pPage,   /* Page into which we are copying */
+  int i,            /* New cell becomes the i-th cell of the page */
+  u8 *pCell,        /* Content of the new cell */
+  int sz,           /* Bytes of content in pCell */
+  u8 *pTemp,        /* Temp storage space for pCell, if needed */
+  Pgno iChild       /* If non-zero, replace first 4 bytes with this value */
+){
+  int idx = 0;      /* Where to write new cell content in data[] */
+  int j;            /* Loop counter */
+  u8 *data;         /* The content of the whole page */
+  u8 *pIns;         /* The point in pPage->aCellIdx[] where no cell inserted */
+
+  assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
+  assert( MX_CELL(pPage->pBt)<=10921 );
+  assert( pPage->nCell<=MX_CELL(pPage->pBt) || CORRUPT_DB );
+  assert( pPage->nOverflow<=ArraySize(pPage->apOvfl) );
+  assert( ArraySize(pPage->apOvfl)==ArraySize(pPage->aiOvfl) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( sz==pPage->xCellSize(pPage, pCell) || CORRUPT_DB );
+  assert( pPage->nFree>=0 );
+  assert( iChild>0 );
+  if( pPage->nOverflow || sz+2>pPage->nFree ){
+    if( pTemp ){
+      memcpy(pTemp, pCell, sz);
+      pCell = pTemp;
+    }
+    put4byte(pCell, iChild);
+    j = pPage->nOverflow++;
+    /* Comparison against ArraySize-1 since we hold back one extra slot
+    ** as a contingency.  In other words, never need more than 3 overflow
+    ** slots but 4 are allocated, just to be safe. */
+    assert( j < ArraySize(pPage->apOvfl)-1 );
+    pPage->apOvfl[j] = pCell;
+    pPage->aiOvfl[j] = (u16)i;
+
+    /* When multiple overflows occur, they are always sequential and in
+    ** sorted order.  This invariants arise because multiple overflows can
+    ** only occur when inserting divider cells into the parent page during
+    ** balancing, and the dividers are adjacent and sorted.
+    */
+    assert( j==0 || pPage->aiOvfl[j-1]<(u16)i ); /* Overflows in sorted order */
+    assert( j==0 || i==pPage->aiOvfl[j-1]+1 );   /* Overflows are sequential */
+  }else{
+    int rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( NEVER(rc!=SQLITE_OK) ){
+      return rc;
+    }
+    assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+    data = pPage->aData;
+    assert( &data[pPage->cellOffset]==pPage->aCellIdx );
+    rc = allocateSpace(pPage, sz, &idx);
+    if( rc ){ return rc; }
+    /* The allocateSpace() routine guarantees the following properties
+    ** if it returns successfully */
+    assert( idx >= 0 );
+    assert( idx >= pPage->cellOffset+2*pPage->nCell+2 || CORRUPT_DB );
+    assert( idx+sz <= (int)pPage->pBt->usableSize );
+    pPage->nFree -= (u16)(2 + sz);
+    /* In a corrupt database where an entry in the cell index section of
+    ** a btree page has a value of 3 or less, the pCell value might point
+    ** as many as 4 bytes in front of the start of the aData buffer for
+    ** the source page.  Make sure this does not cause problems by not
+    ** reading the first 4 bytes */
+    memcpy(&data[idx+4], pCell+4, sz-4);
+    put4byte(&data[idx], iChild);
+    pIns = pPage->aCellIdx + i*2;
+    memmove(pIns+2, pIns, 2*(pPage->nCell - i));
+    put2byte(pIns, idx);
+    pPage->nCell++;
+    /* increment the cell count */
+    if( (++data[pPage->hdrOffset+4])==0 ) data[pPage->hdrOffset+3]++;
+    assert( get2byte(&data[pPage->hdrOffset+3])==pPage->nCell || CORRUPT_DB );
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pPage->pBt->autoVacuum ){
+      int rc2 = SQLITE_OK;
+      /* The cell may contain a pointer to an overflow page. If so, write
+      ** the entry for the overflow page into the pointer map.
+      */
+      ptrmapPutOvflPtr(pPage, pPage, pCell, &rc2);
+      if( rc2 ) return rc2;
+    }
+#endif
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This variant of insertCell() assumes that the pTemp and iChild
+** parameters are both zero.  Use this variant in sqlite3BtreeInsert()
+** for performance improvement, and also so that this variant is only
+** called from that one place, and is thus inlined, and thus runs must
+** faster.
+**
+** Fixes or enhancements to this routine should be reflected into
+** the insertCell() routine.
+*/
+static int insertCellFast(
+  MemPage *pPage,   /* Page into which we are copying */
+  int i,            /* New cell becomes the i-th cell of the page */
+  u8 *pCell,        /* Content of the new cell */
+  int sz            /* Bytes of content in pCell */
+){
+  int idx = 0;      /* Where to write new cell content in data[] */
+  int j;            /* Loop counter */
+  u8 *data;         /* The content of the whole page */
+  u8 *pIns;         /* The point in pPage->aCellIdx[] where no cell inserted */
+
+  assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
+  assert( MX_CELL(pPage->pBt)<=10921 );
+  assert( pPage->nCell<=MX_CELL(pPage->pBt) || CORRUPT_DB );
+  assert( pPage->nOverflow<=ArraySize(pPage->apOvfl) );
+  assert( ArraySize(pPage->apOvfl)==ArraySize(pPage->aiOvfl) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( sz==pPage->xCellSize(pPage, pCell) || CORRUPT_DB );
+  assert( pPage->nFree>=0 );
+  assert( pPage->nOverflow==0 );
+  if( sz+2>pPage->nFree ){
+    j = pPage->nOverflow++;
+    /* Comparison against ArraySize-1 since we hold back one extra slot
+    ** as a contingency.  In other words, never need more than 3 overflow
+    ** slots but 4 are allocated, just to be safe. */
+    assert( j < ArraySize(pPage->apOvfl)-1 );
+    pPage->apOvfl[j] = pCell;
+    pPage->aiOvfl[j] = (u16)i;
+
+    /* When multiple overflows occur, they are always sequential and in
+    ** sorted order.  This invariants arise because multiple overflows can
+    ** only occur when inserting divider cells into the parent page during
+    ** balancing, and the dividers are adjacent and sorted.
+    */
+    assert( j==0 || pPage->aiOvfl[j-1]<(u16)i ); /* Overflows in sorted order */
+    assert( j==0 || i==pPage->aiOvfl[j-1]+1 );   /* Overflows are sequential */
+  }else{
+    int rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+    data = pPage->aData;
+    assert( &data[pPage->cellOffset]==pPage->aCellIdx );
+    rc = allocateSpace(pPage, sz, &idx);
+    if( rc ){ return rc; }
+    /* The allocateSpace() routine guarantees the following properties
+    ** if it returns successfully */
+    assert( idx >= 0 );
+    assert( idx >= pPage->cellOffset+2*pPage->nCell+2 || CORRUPT_DB );
+    assert( idx+sz <= (int)pPage->pBt->usableSize );
+    pPage->nFree -= (u16)(2 + sz);
+    memcpy(&data[idx], pCell, sz);
+    pIns = pPage->aCellIdx + i*2;
+    memmove(pIns+2, pIns, 2*(pPage->nCell - i));
+    put2byte(pIns, idx);
+    pPage->nCell++;
+    /* increment the cell count */
+    if( (++data[pPage->hdrOffset+4])==0 ) data[pPage->hdrOffset+3]++;
+    assert( get2byte(&data[pPage->hdrOffset+3])==pPage->nCell || CORRUPT_DB );
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pPage->pBt->autoVacuum ){
+      int rc2 = SQLITE_OK;
+      /* The cell may contain a pointer to an overflow page. If so, write
+      ** the entry for the overflow page into the pointer map.
+      */
+      ptrmapPutOvflPtr(pPage, pPage, pCell, &rc2);
+      if( rc2 ) return rc2;
+    }
+#endif
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The following parameters determine how many adjacent pages get involved
+** in a balancing operation.  NN is the number of neighbors on either side
+** of the page that participate in the balancing operation.  NB is the
+** total number of pages that participate, including the target page and
+** NN neighbors on either side.
+**
+** The minimum value of NN is 1 (of course).  Increasing NN above 1
+** (to 2 or 3) gives a modest improvement in SELECT and DELETE performance
+** in exchange for a larger degradation in INSERT and UPDATE performance.
+** The value of NN appears to give the best results overall.
+**
+** (Later:) The description above makes it seem as if these values are
+** tunable - as if you could change them and recompile and it would all work.
+** But that is unlikely.  NB has been 3 since the inception of SQLite and
+** we have never tested any other value.
+*/
+#define NN 1             /* Number of neighbors on either side of pPage */
+#define NB 3             /* (NN*2+1): Total pages involved in the balance */
+
+/*
+** A CellArray object contains a cache of pointers and sizes for a
+** consecutive sequence of cells that might be held on multiple pages.
+**
+** The cells in this array are the divider cell or cells from the pParent
+** page plus up to three child pages.  There are a total of nCell cells.
+**
+** pRef is a pointer to one of the pages that contributes cells.  This is
+** used to access information such as MemPage.intKey and MemPage.pBt->pageSize
+** which should be common to all pages that contribute cells to this array.
+**
+** apCell[] and szCell[] hold, respectively, pointers to the start of each
+** cell and the size of each cell.  Some of the apCell[] pointers might refer
+** to overflow cells.  In other words, some apCel[] pointers might not point
+** to content area of the pages.
+**
+** A szCell[] of zero means the size of that cell has not yet been computed.
+**
+** The cells come from as many as four different pages:
+**
+**             -----------
+**             | Parent  |
+**             -----------
+**            /     |     \
+**           /      |      \
+**  ---------   ---------   ---------
+**  |Child-1|   |Child-2|   |Child-3|
+**  ---------   ---------   ---------
+**
+** The order of cells is in the array is for an index btree is:
+**
+**       1.  All cells from Child-1 in order
+**       2.  The first divider cell from Parent
+**       3.  All cells from Child-2 in order
+**       4.  The second divider cell from Parent
+**       5.  All cells from Child-3 in order
+**
+** For a table-btree (with rowids) the items 2 and 4 are empty because
+** content exists only in leaves and there are no divider cells.
+**
+** For an index btree, the apEnd[] array holds pointer to the end of page
+** for Child-1, the Parent, Child-2, the Parent (again), and Child-3,
+** respectively. The ixNx[] array holds the number of cells contained in
+** each of these 5 stages, and all stages to the left.  Hence:
+**
+**    ixNx[0] = Number of cells in Child-1.
+**    ixNx[1] = Number of cells in Child-1 plus 1 for first divider.
+**    ixNx[2] = Number of cells in Child-1 and Child-2 + 1 for 1st divider.
+**    ixNx[3] = Number of cells in Child-1 and Child-2 + both divider cells
+**    ixNx[4] = Total number of cells.
+**
+** For a table-btree, the concept is similar, except only apEnd[0]..apEnd[2]
+** are used and they point to the leaf pages only, and the ixNx value are:
+**
+**    ixNx[0] = Number of cells in Child-1.
+**    ixNx[1] = Number of cells in Child-1 and Child-2.
+**    ixNx[2] = Total number of cells.
+**
+** Sometimes when deleting, a child page can have zero cells.  In those
+** cases, ixNx[] entries with higher indexes, and the corresponding apEnd[]
+** entries, shift down.  The end result is that each ixNx[] entry should
+** be larger than the previous
+*/
+typedef struct CellArray CellArray;
+struct CellArray {
+  int nCell;              /* Number of cells in apCell[] */
+  MemPage *pRef;          /* Reference page */
+  u8 **apCell;            /* All cells begin balanced */
+  u16 *szCell;            /* Local size of all cells in apCell[] */
+  u8 *apEnd[NB*2];        /* MemPage.aDataEnd values */
+  int ixNx[NB*2];         /* Index of at which we move to the next apEnd[] */
+};
+
+/*
+** Make sure the cell sizes at idx, idx+1, ..., idx+N-1 have been
+** computed.
+*/
+static void populateCellCache(CellArray *p, int idx, int N){
+  MemPage *pRef = p->pRef;
+  u16 *szCell = p->szCell;
+  assert( idx>=0 && idx+N<=p->nCell );
+  while( N>0 ){
+    assert( p->apCell[idx]!=0 );
+    if( szCell[idx]==0 ){
+      szCell[idx] = pRef->xCellSize(pRef, p->apCell[idx]);
+    }else{
+      assert( CORRUPT_DB ||
+              szCell[idx]==pRef->xCellSize(pRef, p->apCell[idx]) );
+    }
+    idx++;
+    N--;
+  }
+}
+
+/*
+** Return the size of the Nth element of the cell array
+*/
+static SQLITE_NOINLINE u16 computeCellSize(CellArray *p, int N){
+  assert( N>=0 && N<p->nCell );
+  assert( p->szCell[N]==0 );
+  p->szCell[N] = p->pRef->xCellSize(p->pRef, p->apCell[N]);
+  return p->szCell[N];
+}
+static u16 cachedCellSize(CellArray *p, int N){
+  assert( N>=0 && N<p->nCell );
+  if( p->szCell[N] ) return p->szCell[N];
+  return computeCellSize(p, N);
+}
+
+/*
+** Array apCell[] contains pointers to nCell b-tree page cells. The
+** szCell[] array contains the size in bytes of each cell. This function
+** replaces the current contents of page pPg with the contents of the cell
+** array.
+**
+** Some of the cells in apCell[] may currently be stored in pPg. This
+** function works around problems caused by this by making a copy of any
+** such cells before overwriting the page data.
+**
+** The MemPage.nFree field is invalidated by this function. It is the
+** responsibility of the caller to set it correctly.
+*/
+static int rebuildPage(
+  CellArray *pCArray,             /* Content to be added to page pPg */
+  int iFirst,                     /* First cell in pCArray to use */
+  int nCell,                      /* Final number of cells on page */
+  MemPage *pPg                    /* The page to be reconstructed */
+){
+  const int hdr = pPg->hdrOffset;          /* Offset of header on pPg */
+  u8 * const aData = pPg->aData;           /* Pointer to data for pPg */
+  const int usableSize = pPg->pBt->usableSize;
+  u8 * const pEnd = &aData[usableSize];
+  int i = iFirst;                 /* Which cell to copy from pCArray*/
+  u32 j;                          /* Start of cell content area */
+  int iEnd = i+nCell;             /* Loop terminator */
+  u8 *pCellptr = pPg->aCellIdx;
+  u8 *pTmp = sqlite3PagerTempSpace(pPg->pBt->pPager);
+  u8 *pData;
+  int k;                          /* Current slot in pCArray->apEnd[] */
+  u8 *pSrcEnd;                    /* Current pCArray->apEnd[k] value */
+
+  assert( nCell>0 );
+  assert( i<iEnd );
+  j = get2byte(&aData[hdr+5]);
+  if( j>(u32)usableSize ){ j = 0; }
+  memcpy(&pTmp[j], &aData[j], usableSize - j);
+
+  assert( pCArray->ixNx[NB*2-1]>i );
+  for(k=0; pCArray->ixNx[k]<=i; k++){}
+  pSrcEnd = pCArray->apEnd[k];
+
+  pData = pEnd;
+  while( 1/*exit by break*/ ){
+    u8 *pCell = pCArray->apCell[i];
+    u16 sz = pCArray->szCell[i];
+    assert( sz>0 );
+    if( SQLITE_WITHIN(pCell,aData+j,pEnd) ){
+      if( ((uptr)(pCell+sz))>(uptr)pEnd ) return SQLITE_CORRUPT_BKPT;
+      pCell = &pTmp[pCell - aData];
+    }else if( (uptr)(pCell+sz)>(uptr)pSrcEnd
+           && (uptr)(pCell)<(uptr)pSrcEnd
+    ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+
+    pData -= sz;
+    put2byte(pCellptr, (pData - aData));
+    pCellptr += 2;
+    if( pData < pCellptr ) return SQLITE_CORRUPT_BKPT;
+    memmove(pData, pCell, sz);
+    assert( sz==pPg->xCellSize(pPg, pCell) || CORRUPT_DB );
+    i++;
+    if( i>=iEnd ) break;
+    if( pCArray->ixNx[k]<=i ){
+      k++;
+      pSrcEnd = pCArray->apEnd[k];
+    }
+  }
+
+  /* The pPg->nFree field is now set incorrectly. The caller will fix it. */
+  pPg->nCell = nCell;
+  pPg->nOverflow = 0;
+
+  put2byte(&aData[hdr+1], 0);
+  put2byte(&aData[hdr+3], pPg->nCell);
+  put2byte(&aData[hdr+5], pData - aData);
+  aData[hdr+7] = 0x00;
+  return SQLITE_OK;
+}
+
+/*
+** The pCArray objects contains pointers to b-tree cells and the cell sizes.
+** This function attempts to add the cells stored in the array to page pPg.
+** If it cannot (because the page needs to be defragmented before the cells
+** will fit), non-zero is returned. Otherwise, if the cells are added
+** successfully, zero is returned.
+**
+** Argument pCellptr points to the first entry in the cell-pointer array
+** (part of page pPg) to populate. After cell apCell[0] is written to the
+** page body, a 16-bit offset is written to pCellptr. And so on, for each
+** cell in the array. It is the responsibility of the caller to ensure
+** that it is safe to overwrite this part of the cell-pointer array.
+**
+** When this function is called, *ppData points to the start of the
+** content area on page pPg. If the size of the content area is extended,
+** *ppData is updated to point to the new start of the content area
+** before returning.
+**
+** Finally, argument pBegin points to the byte immediately following the
+** end of the space required by this page for the cell-pointer area (for
+** all cells - not just those inserted by the current call). If the content
+** area must be extended to before this point in order to accommodate all
+** cells in apCell[], then the cells do not fit and non-zero is returned.
+*/
+static int pageInsertArray(
+  MemPage *pPg,                   /* Page to add cells to */
+  u8 *pBegin,                     /* End of cell-pointer array */
+  u8 **ppData,                    /* IN/OUT: Page content-area pointer */
+  u8 *pCellptr,                   /* Pointer to cell-pointer area */
+  int iFirst,                     /* Index of first cell to add */
+  int nCell,                      /* Number of cells to add to pPg */
+  CellArray *pCArray              /* Array of cells */
+){
+  int i = iFirst;                 /* Loop counter - cell index to insert */
+  u8 *aData = pPg->aData;         /* Complete page */
+  u8 *pData = *ppData;            /* Content area.  A subset of aData[] */
+  int iEnd = iFirst + nCell;      /* End of loop. One past last cell to ins */
+  int k;                          /* Current slot in pCArray->apEnd[] */
+  u8 *pEnd;                       /* Maximum extent of cell data */
+  assert( CORRUPT_DB || pPg->hdrOffset==0 );    /* Never called on page 1 */
+  if( iEnd<=iFirst ) return 0;
+  assert( pCArray->ixNx[NB*2-1]>i );
+  for(k=0; pCArray->ixNx[k]<=i ; k++){}
+  pEnd = pCArray->apEnd[k];
+  while( 1 /*Exit by break*/ ){
+    int sz, rc;
+    u8 *pSlot;
+    assert( pCArray->szCell[i]!=0 );
+    sz = pCArray->szCell[i];
+    if( (aData[1]==0 && aData[2]==0) || (pSlot = pageFindSlot(pPg,sz,&rc))==0 ){
+      if( (pData - pBegin)<sz ) return 1;
+      pData -= sz;
+      pSlot = pData;
+    }
+    /* pSlot and pCArray->apCell[i] will never overlap on a well-formed
+    ** database.  But they might for a corrupt database.  Hence use memmove()
+    ** since memcpy() sends SIGABORT with overlapping buffers on OpenBSD */
+    assert( (pSlot+sz)<=pCArray->apCell[i]
+         || pSlot>=(pCArray->apCell[i]+sz)
+         || CORRUPT_DB );
+    if( (uptr)(pCArray->apCell[i]+sz)>(uptr)pEnd
+     && (uptr)(pCArray->apCell[i])<(uptr)pEnd
+    ){
+      assert( CORRUPT_DB );
+      (void)SQLITE_CORRUPT_BKPT;
+      return 1;
+    }
+    memmove(pSlot, pCArray->apCell[i], sz);
+    put2byte(pCellptr, (pSlot - aData));
+    pCellptr += 2;
+    i++;
+    if( i>=iEnd ) break;
+    if( pCArray->ixNx[k]<=i ){
+      k++;
+      pEnd = pCArray->apEnd[k];
+    }
+  }
+  *ppData = pData;
+  return 0;
+}
+
+/*
+** The pCArray object contains pointers to b-tree cells and their sizes.
+**
+** This function adds the space associated with each cell in the array
+** that is currently stored within the body of pPg to the pPg free-list.
+** The cell-pointers and other fields of the page are not updated.
+**
+** This function returns the total number of cells added to the free-list.
+*/
+static int pageFreeArray(
+  MemPage *pPg,                   /* Page to edit */
+  int iFirst,                     /* First cell to delete */
+  int nCell,                      /* Cells to delete */
+  CellArray *pCArray              /* Array of cells */
+){
+  u8 * const aData = pPg->aData;
+  u8 * const pEnd = &aData[pPg->pBt->usableSize];
+  u8 * const pStart = &aData[pPg->hdrOffset + 8 + pPg->childPtrSize];
+  int nRet = 0;
+  int i, j;
+  int iEnd = iFirst + nCell;
+  int nFree = 0;
+  int aOfst[10];
+  int aAfter[10];
+
+  for(i=iFirst; i<iEnd; i++){
+    u8 *pCell = pCArray->apCell[i];
+    if( SQLITE_WITHIN(pCell, pStart, pEnd) ){
+      int sz;
+      int iAfter;
+      int iOfst;
+      /* No need to use cachedCellSize() here.  The sizes of all cells that
+      ** are to be freed have already been computing while deciding which
+      ** cells need freeing */
+      sz = pCArray->szCell[i];  assert( sz>0 );
+      iOfst = (u16)(pCell - aData);
+      iAfter = iOfst+sz;
+      for(j=0; j<nFree; j++){
+        if( aOfst[j]==iAfter ){
+          aOfst[j] = iOfst;
+          break;
+        }else if( aAfter[j]==iOfst ){
+          aAfter[j] = iAfter;
+          break;
+        }
+      }
+      if( j>=nFree ){
+        if( nFree>=(int)(sizeof(aOfst)/sizeof(aOfst[0])) ){
+          for(j=0; j<nFree; j++){
+            freeSpace(pPg, aOfst[j], aAfter[j]-aOfst[j]);
+          }
+          nFree = 0;
+        }
+        aOfst[nFree] = iOfst;
+        aAfter[nFree] = iAfter;
+        if( &aData[iAfter]>pEnd ) return 0;
+        nFree++;
+      }
+      nRet++;
+    }
+  }
+  for(j=0; j<nFree; j++){
+    freeSpace(pPg, aOfst[j], aAfter[j]-aOfst[j]);
+  }
+  return nRet;
+}
+
+/*
+** pCArray contains pointers to and sizes of all cells in the page being
+** balanced.  The current page, pPg, has pPg->nCell cells starting with
+** pCArray->apCell[iOld].  After balancing, this page should hold nNew cells
+** starting at apCell[iNew].
+**
+** This routine makes the necessary adjustments to pPg so that it contains
+** the correct cells after being balanced.
+**
+** The pPg->nFree field is invalid when this function returns. It is the
+** responsibility of the caller to set it correctly.
+*/
+static int editPage(
+  MemPage *pPg,                   /* Edit this page */
+  int iOld,                       /* Index of first cell currently on page */
+  int iNew,                       /* Index of new first cell on page */
+  int nNew,                       /* Final number of cells on page */
+  CellArray *pCArray              /* Array of cells and sizes */
+){
+  u8 * const aData = pPg->aData;
+  const int hdr = pPg->hdrOffset;
+  u8 *pBegin = &pPg->aCellIdx[nNew * 2];
+  int nCell = pPg->nCell;       /* Cells stored on pPg */
+  u8 *pData;
+  u8 *pCellptr;
+  int i;
+  int iOldEnd = iOld + pPg->nCell + pPg->nOverflow;
+  int iNewEnd = iNew + nNew;
+
+#ifdef SQLITE_DEBUG
+  u8 *pTmp = sqlite3PagerTempSpace(pPg->pBt->pPager);
+  memcpy(pTmp, aData, pPg->pBt->usableSize);
+#endif
+
+  /* Remove cells from the start and end of the page */
+  assert( nCell>=0 );
+  if( iOld<iNew ){
+    int nShift = pageFreeArray(pPg, iOld, iNew-iOld, pCArray);
+    if( NEVER(nShift>nCell) ) return SQLITE_CORRUPT_BKPT;
+    memmove(pPg->aCellIdx, &pPg->aCellIdx[nShift*2], nCell*2);
+    nCell -= nShift;
+  }
+  if( iNewEnd < iOldEnd ){
+    int nTail = pageFreeArray(pPg, iNewEnd, iOldEnd - iNewEnd, pCArray);
+    assert( nCell>=nTail );
+    nCell -= nTail;
+  }
+
+  pData = &aData[get2byte(&aData[hdr+5])];
+  if( pData<pBegin ) goto editpage_fail;
+  if( NEVER(pData>pPg->aDataEnd) ) goto editpage_fail;
+
+  /* Add cells to the start of the page */
+  if( iNew<iOld ){
+    int nAdd = MIN(nNew,iOld-iNew);
+    assert( (iOld-iNew)<nNew || nCell==0 || CORRUPT_DB );
+    assert( nAdd>=0 );
+    pCellptr = pPg->aCellIdx;
+    memmove(&pCellptr[nAdd*2], pCellptr, nCell*2);
+    if( pageInsertArray(
+          pPg, pBegin, &pData, pCellptr,
+          iNew, nAdd, pCArray
+    ) ) goto editpage_fail;
+    nCell += nAdd;
+  }
+
+  /* Add any overflow cells */
+  for(i=0; i<pPg->nOverflow; i++){
+    int iCell = (iOld + pPg->aiOvfl[i]) - iNew;
+    if( iCell>=0 && iCell<nNew ){
+      pCellptr = &pPg->aCellIdx[iCell * 2];
+      if( nCell>iCell ){
+        memmove(&pCellptr[2], pCellptr, (nCell - iCell) * 2);
+      }
+      nCell++;
+      cachedCellSize(pCArray, iCell+iNew);
+      if( pageInsertArray(
+            pPg, pBegin, &pData, pCellptr,
+            iCell+iNew, 1, pCArray
+      ) ) goto editpage_fail;
+    }
+  }
+
+  /* Append cells to the end of the page */
+  assert( nCell>=0 );
+  pCellptr = &pPg->aCellIdx[nCell*2];
+  if( pageInsertArray(
+        pPg, pBegin, &pData, pCellptr,
+        iNew+nCell, nNew-nCell, pCArray
+  ) ) goto editpage_fail;
+
+  pPg->nCell = nNew;
+  pPg->nOverflow = 0;
+
+  put2byte(&aData[hdr+3], pPg->nCell);
+  put2byte(&aData[hdr+5], pData - aData);
+
+#ifdef SQLITE_DEBUG
+  for(i=0; i<nNew && !CORRUPT_DB; i++){
+    u8 *pCell = pCArray->apCell[i+iNew];
+    int iOff = get2byteAligned(&pPg->aCellIdx[i*2]);
+    if( SQLITE_WITHIN(pCell, aData, &aData[pPg->pBt->usableSize]) ){
+      pCell = &pTmp[pCell - aData];
+    }
+    assert( 0==memcmp(pCell, &aData[iOff],
+            pCArray->pRef->xCellSize(pCArray->pRef, pCArray->apCell[i+iNew])) );
+  }
+#endif
+
+  return SQLITE_OK;
+ editpage_fail:
+  /* Unable to edit this page. Rebuild it from scratch instead. */
+  if( nNew<1 ) return SQLITE_CORRUPT_BKPT;
+  populateCellCache(pCArray, iNew, nNew);
+  return rebuildPage(pCArray, iNew, nNew, pPg);
+}
+
+
+#ifndef SQLITE_OMIT_QUICKBALANCE
+/*
+** This version of balance() handles the common special case where
+** a new entry is being inserted on the extreme right-end of the
+** tree, in other words, when the new entry will become the largest
+** entry in the tree.
+**
+** Instead of trying to balance the 3 right-most leaf pages, just add
+** a new page to the right-hand side and put the one new entry in
+** that page.  This leaves the right side of the tree somewhat
+** unbalanced.  But odds are that we will be inserting new entries
+** at the end soon afterwards so the nearly empty page will quickly
+** fill up.  On average.
+**
+** pPage is the leaf page which is the right-most page in the tree.
+** pParent is its parent.  pPage must have a single overflow entry
+** which is also the right-most entry on the page.
+**
+** The pSpace buffer is used to store a temporary copy of the divider
+** cell that will be inserted into pParent. Such a cell consists of a 4
+** byte page number followed by a variable length integer. In other
+** words, at most 13 bytes. Hence the pSpace buffer must be at
+** least 13 bytes in size.
+*/
+static int balance_quick(MemPage *pParent, MemPage *pPage, u8 *pSpace){
+  BtShared *const pBt = pPage->pBt;    /* B-Tree Database */
+  MemPage *pNew;                       /* Newly allocated page */
+  int rc;                              /* Return Code */
+  Pgno pgnoNew;                        /* Page number of pNew */
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+  assert( pPage->nOverflow==1 );
+
+  if( pPage->nCell==0 ) return SQLITE_CORRUPT_BKPT;  /* dbfuzz001.test */
+  assert( pPage->nFree>=0 );
+  assert( pParent->nFree>=0 );
+
+  /* Allocate a new page. This page will become the right-sibling of
+  ** pPage. Make the parent page writable, so that the new divider cell
+  ** may be inserted. If both these operations are successful, proceed.
+  */
+  rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
+
+  if( rc==SQLITE_OK ){
+
+    u8 *pOut = &pSpace[4];
+    u8 *pCell = pPage->apOvfl[0];
+    u16 szCell = pPage->xCellSize(pPage, pCell);
+    u8 *pStop;
+    CellArray b;
+
+    assert( sqlite3PagerIswriteable(pNew->pDbPage) );
+    assert( CORRUPT_DB || pPage->aData[0]==(PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF) );
+    zeroPage(pNew, PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF);
+    b.nCell = 1;
+    b.pRef = pPage;
+    b.apCell = &pCell;
+    b.szCell = &szCell;
+    b.apEnd[0] = pPage->aDataEnd;
+    b.ixNx[0] = 2;
+    b.ixNx[NB*2-1] = 0x7fffffff;
+    rc = rebuildPage(&b, 0, 1, pNew);
+    if( NEVER(rc) ){
+      releasePage(pNew);
+      return rc;
+    }
+    pNew->nFree = pBt->usableSize - pNew->cellOffset - 2 - szCell;
+
+    /* If this is an auto-vacuum database, update the pointer map
+    ** with entries for the new page, and any pointer from the
+    ** cell on the page to an overflow page. If either of these
+    ** operations fails, the return code is set, but the contents
+    ** of the parent page are still manipulated by the code below.
+    ** That is Ok, at this point the parent page is guaranteed to
+    ** be marked as dirty. Returning an error code will cause a
+    ** rollback, undoing any changes made to the parent page.
+    */
+    if( ISAUTOVACUUM(pBt) ){
+      ptrmapPut(pBt, pgnoNew, PTRMAP_BTREE, pParent->pgno, &rc);
+      if( szCell>pNew->minLocal ){
+        ptrmapPutOvflPtr(pNew, pNew, pCell, &rc);
+      }
+    }
+
+    /* Create a divider cell to insert into pParent. The divider cell
+    ** consists of a 4-byte page number (the page number of pPage) and
+    ** a variable length key value (which must be the same value as the
+    ** largest key on pPage).
+    **
+    ** To find the largest key value on pPage, first find the right-most
+    ** cell on pPage. The first two fields of this cell are the
+    ** record-length (a variable length integer at most 32-bits in size)
+    ** and the key value (a variable length integer, may have any value).
+    ** The first of the while(...) loops below skips over the record-length
+    ** field. The second while(...) loop copies the key value from the
+    ** cell on pPage into the pSpace buffer.
+    */
+    pCell = findCell(pPage, pPage->nCell-1);
+    pStop = &pCell[9];
+    while( (*(pCell++)&0x80) && pCell<pStop );
+    pStop = &pCell[9];
+    while( ((*(pOut++) = *(pCell++))&0x80) && pCell<pStop );
+
+    /* Insert the new divider cell into pParent. */
+    if( rc==SQLITE_OK ){
+      rc = insertCell(pParent, pParent->nCell, pSpace, (int)(pOut-pSpace),
+                      0, pPage->pgno);
+    }
+
+    /* Set the right-child pointer of pParent to point to the new page. */
+    put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew);
+
+    /* Release the reference to the new page. */
+    releasePage(pNew);
+  }
+
+  return rc;
+}
+#endif /* SQLITE_OMIT_QUICKBALANCE */
+
+#if 0
+/*
+** This function does not contribute anything to the operation of SQLite.
+** it is sometimes activated temporarily while debugging code responsible
+** for setting pointer-map entries.
+*/
+static int ptrmapCheckPages(MemPage **apPage, int nPage){
+  int i, j;
+  for(i=0; i<nPage; i++){
+    Pgno n;
+    u8 e;
+    MemPage *pPage = apPage[i];
+    BtShared *pBt = pPage->pBt;
+    assert( pPage->isInit );
+
+    for(j=0; j<pPage->nCell; j++){
+      CellInfo info;
+      u8 *z;
+
+      z = findCell(pPage, j);
+      pPage->xParseCell(pPage, z, &info);
+      if( info.nLocal<info.nPayload ){
+        Pgno ovfl = get4byte(&z[info.nSize-4]);
+        ptrmapGet(pBt, ovfl, &e, &n);
+        assert( n==pPage->pgno && e==PTRMAP_OVERFLOW1 );
+      }
+      if( !pPage->leaf ){
+        Pgno child = get4byte(z);
+        ptrmapGet(pBt, child, &e, &n);
+        assert( n==pPage->pgno && e==PTRMAP_BTREE );
+      }
+    }
+    if( !pPage->leaf ){
+      Pgno child = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+      ptrmapGet(pBt, child, &e, &n);
+      assert( n==pPage->pgno && e==PTRMAP_BTREE );
+    }
+  }
+  return 1;
+}
+#endif
+
+/*
+** This function is used to copy the contents of the b-tree node stored
+** on page pFrom to page pTo. If page pFrom was not a leaf page, then
+** the pointer-map entries for each child page are updated so that the
+** parent page stored in the pointer map is page pTo. If pFrom contained
+** any cells with overflow page pointers, then the corresponding pointer
+** map entries are also updated so that the parent page is page pTo.
+**
+** If pFrom is currently carrying any overflow cells (entries in the
+** MemPage.apOvfl[] array), they are not copied to pTo.
+**
+** Before returning, page pTo is reinitialized using btreeInitPage().
+**
+** The performance of this function is not critical. It is only used by
+** the balance_shallower() and balance_deeper() procedures, neither of
+** which are called often under normal circumstances.
+*/
+static void copyNodeContent(MemPage *pFrom, MemPage *pTo, int *pRC){
+  if( (*pRC)==SQLITE_OK ){
+    BtShared * const pBt = pFrom->pBt;
+    u8 * const aFrom = pFrom->aData;
+    u8 * const aTo = pTo->aData;
+    int const iFromHdr = pFrom->hdrOffset;
+    int const iToHdr = ((pTo->pgno==1) ? 100 : 0);
+    int rc;
+    int iData;
+
+
+    assert( pFrom->isInit );
+    assert( pFrom->nFree>=iToHdr );
+    assert( get2byte(&aFrom[iFromHdr+5]) <= (int)pBt->usableSize );
+
+    /* Copy the b-tree node content from page pFrom to page pTo. */
+    iData = get2byte(&aFrom[iFromHdr+5]);
+    memcpy(&aTo[iData], &aFrom[iData], pBt->usableSize-iData);
+    memcpy(&aTo[iToHdr], &aFrom[iFromHdr], pFrom->cellOffset + 2*pFrom->nCell);
+
+    /* Reinitialize page pTo so that the contents of the MemPage structure
+    ** match the new data. The initialization of pTo can actually fail under
+    ** fairly obscure circumstances, even though it is a copy of initialized
+    ** page pFrom.
+    */
+    pTo->isInit = 0;
+    rc = btreeInitPage(pTo);
+    if( rc==SQLITE_OK ) rc = btreeComputeFreeSpace(pTo);
+    if( rc!=SQLITE_OK ){
+      *pRC = rc;
+      return;
+    }
+
+    /* If this is an auto-vacuum database, update the pointer-map entries
+    ** for any b-tree or overflow pages that pTo now contains the pointers to.
+    */
+    if( ISAUTOVACUUM(pBt) ){
+      *pRC = setChildPtrmaps(pTo);
+    }
+  }
+}
+
+/*
+** This routine redistributes cells on the iParentIdx'th child of pParent
+** (hereafter "the page") and up to 2 siblings so that all pages have about the
+** same amount of free space. Usually a single sibling on either side of the
+** page are used in the balancing, though both siblings might come from one
+** side if the page is the first or last child of its parent. If the page
+** has fewer than 2 siblings (something which can only happen if the page
+** is a root page or a child of a root page) then all available siblings
+** participate in the balancing.
+**
+** The number of siblings of the page might be increased or decreased by
+** one or two in an effort to keep pages nearly full but not over full.
+**
+** Note that when this routine is called, some of the cells on the page
+** might not actually be stored in MemPage.aData[]. This can happen
+** if the page is overfull. This routine ensures that all cells allocated
+** to the page and its siblings fit into MemPage.aData[] before returning.
+**
+** In the course of balancing the page and its siblings, cells may be
+** inserted into or removed from the parent page (pParent). Doing so
+** may cause the parent page to become overfull or underfull. If this
+** happens, it is the responsibility of the caller to invoke the correct
+** balancing routine to fix this problem (see the balance() routine).
+**
+** If this routine fails for any reason, it might leave the database
+** in a corrupted state. So if this routine fails, the database should
+** be rolled back.
+**
+** The third argument to this function, aOvflSpace, is a pointer to a
+** buffer big enough to hold one page. If while inserting cells into the parent
+** page (pParent) the parent page becomes overfull, this buffer is
+** used to store the parent's overflow cells. Because this function inserts
+** a maximum of four divider cells into the parent page, and the maximum
+** size of a cell stored within an internal node is always less than 1/4
+** of the page-size, the aOvflSpace[] buffer is guaranteed to be large
+** enough for all overflow cells.
+**
+** If aOvflSpace is set to a null pointer, this function returns
+** SQLITE_NOMEM.
+*/
+static int balance_nonroot(
+  MemPage *pParent,               /* Parent page of siblings being balanced */
+  int iParentIdx,                 /* Index of "the page" in pParent */
+  u8 *aOvflSpace,                 /* page-size bytes of space for parent ovfl */
+  int isRoot,                     /* True if pParent is a root-page */
+  int bBulk                       /* True if this call is part of a bulk load */
+){
+  BtShared *pBt;               /* The whole database */
+  int nMaxCells = 0;           /* Allocated size of apCell, szCell, aFrom. */
+  int nNew = 0;                /* Number of pages in apNew[] */
+  int nOld;                    /* Number of pages in apOld[] */
+  int i, j, k;                 /* Loop counters */
+  int nxDiv;                   /* Next divider slot in pParent->aCell[] */
+  int rc = SQLITE_OK;          /* The return code */
+  u16 leafCorrection;          /* 4 if pPage is a leaf.  0 if not */
+  int leafData;                /* True if pPage is a leaf of a LEAFDATA tree */
+  int usableSpace;             /* Bytes in pPage beyond the header */
+  int pageFlags;               /* Value of pPage->aData[0] */
+  int iSpace1 = 0;             /* First unused byte of aSpace1[] */
+  int iOvflSpace = 0;          /* First unused byte of aOvflSpace[] */
+  int szScratch;               /* Size of scratch memory requested */
+  MemPage *apOld[NB];          /* pPage and up to two siblings */
+  MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
+  u8 *pRight;                  /* Location in parent of right-sibling pointer */
+  u8 *apDiv[NB-1];             /* Divider cells in pParent */
+  int cntNew[NB+2];            /* Index in b.paCell[] of cell after i-th page */
+  int cntOld[NB+2];            /* Old index in b.apCell[] */
+  int szNew[NB+2];             /* Combined size of cells placed on i-th page */
+  u8 *aSpace1;                 /* Space for copies of dividers cells */
+  Pgno pgno;                   /* Temp var to store a page number in */
+  u8 abDone[NB+2];             /* True after i'th new page is populated */
+  Pgno aPgno[NB+2];            /* Page numbers of new pages before shuffling */
+  CellArray b;                 /* Parsed information on cells being balanced */
+
+  memset(abDone, 0, sizeof(abDone));
+  assert( sizeof(b) - sizeof(b.ixNx) == offsetof(CellArray,ixNx) );
+  memset(&b, 0, sizeof(b)-sizeof(b.ixNx[0]));
+  b.ixNx[NB*2-1] = 0x7fffffff;
+  pBt = pParent->pBt;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+
+  /* At this point pParent may have at most one overflow cell. And if
+  ** this overflow cell is present, it must be the cell with
+  ** index iParentIdx. This scenario comes about when this function
+  ** is called (indirectly) from sqlite3BtreeDelete().
+  */
+  assert( pParent->nOverflow==0 || pParent->nOverflow==1 );
+  assert( pParent->nOverflow==0 || pParent->aiOvfl[0]==iParentIdx );
+
+  if( !aOvflSpace ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( pParent->nFree>=0 );
+
+  /* Find the sibling pages to balance. Also locate the cells in pParent
+  ** that divide the siblings. An attempt is made to find NN siblings on
+  ** either side of pPage. More siblings are taken from one side, however,
+  ** if there are fewer than NN siblings on the other side. If pParent
+  ** has NB or fewer children then all children of pParent are taken.
+  **
+  ** This loop also drops the divider cells from the parent page. This
+  ** way, the remainder of the function does not have to deal with any
+  ** overflow cells in the parent page, since if any existed they will
+  ** have already been removed.
+  */
+  i = pParent->nOverflow + pParent->nCell;
+  if( i<2 ){
+    nxDiv = 0;
+  }else{
+    assert( bBulk==0 || bBulk==1 );
+    if( iParentIdx==0 ){
+      nxDiv = 0;
+    }else if( iParentIdx==i ){
+      nxDiv = i-2+bBulk;
+    }else{
+      nxDiv = iParentIdx-1;
+    }
+    i = 2-bBulk;
+  }
+  nOld = i+1;
+  if( (i+nxDiv-pParent->nOverflow)==pParent->nCell ){
+    pRight = &pParent->aData[pParent->hdrOffset+8];
+  }else{
+    pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
+  }
+  pgno = get4byte(pRight);
+  while( 1 ){
+    if( rc==SQLITE_OK ){
+      rc = getAndInitPage(pBt, pgno, &apOld[i], 0);
+    }
+    if( rc ){
+      memset(apOld, 0, (i+1)*sizeof(MemPage*));
+      goto balance_cleanup;
+    }
+    if( apOld[i]->nFree<0 ){
+      rc = btreeComputeFreeSpace(apOld[i]);
+      if( rc ){
+        memset(apOld, 0, (i)*sizeof(MemPage*));
+        goto balance_cleanup;
+      }
+    }
+    nMaxCells += apOld[i]->nCell + ArraySize(pParent->apOvfl);
+    if( (i--)==0 ) break;
+
+    if( pParent->nOverflow && i+nxDiv==pParent->aiOvfl[0] ){
+      apDiv[i] = pParent->apOvfl[0];
+      pgno = get4byte(apDiv[i]);
+      szNew[i] = pParent->xCellSize(pParent, apDiv[i]);
+      pParent->nOverflow = 0;
+    }else{
+      apDiv[i] = findCell(pParent, i+nxDiv-pParent->nOverflow);
+      pgno = get4byte(apDiv[i]);
+      szNew[i] = pParent->xCellSize(pParent, apDiv[i]);
+
+      /* Drop the cell from the parent page. apDiv[i] still points to
+      ** the cell within the parent, even though it has been dropped.
+      ** This is safe because dropping a cell only overwrites the first
+      ** four bytes of it, and this function does not need the first
+      ** four bytes of the divider cell. So the pointer is safe to use
+      ** later on.
+      **
+      ** But not if we are in secure-delete mode. In secure-delete mode,
+      ** the dropCell() routine will overwrite the entire cell with zeroes.
+      ** In this case, temporarily copy the cell into the aOvflSpace[]
+      ** buffer. It will be copied out again as soon as the aSpace[] buffer
+      ** is allocated.  */
+      if( pBt->btsFlags & BTS_FAST_SECURE ){
+        int iOff;
+
+        /* If the following if() condition is not true, the db is corrupted.
+        ** The call to dropCell() below will detect this.  */
+        iOff = SQLITE_PTR_TO_INT(apDiv[i]) - SQLITE_PTR_TO_INT(pParent->aData);
+        if( (iOff+szNew[i])<=(int)pBt->usableSize ){
+          memcpy(&aOvflSpace[iOff], apDiv[i], szNew[i]);
+          apDiv[i] = &aOvflSpace[apDiv[i]-pParent->aData];
+        }
+      }
+      dropCell(pParent, i+nxDiv-pParent->nOverflow, szNew[i], &rc);
+    }
+  }
+
+  /* Make nMaxCells a multiple of 4 in order to preserve 8-byte
+  ** alignment */
+  nMaxCells = (nMaxCells + 3)&~3;
+
+  /*
+  ** Allocate space for memory structures
+  */
+  szScratch =
+       nMaxCells*sizeof(u8*)                       /* b.apCell */
+     + nMaxCells*sizeof(u16)                       /* b.szCell */
+     + pBt->pageSize;                              /* aSpace1 */
+
+  assert( szScratch<=7*(int)pBt->pageSize );
+  b.apCell = sqlite3StackAllocRaw(0, szScratch );
+  if( b.apCell==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto balance_cleanup;
+  }
+  b.szCell = (u16*)&b.apCell[nMaxCells];
+  aSpace1 = (u8*)&b.szCell[nMaxCells];
+  assert( EIGHT_BYTE_ALIGNMENT(aSpace1) );
+
+  /*
+  ** Load pointers to all cells on sibling pages and the divider cells
+  ** into the local b.apCell[] array.  Make copies of the divider cells
+  ** into space obtained from aSpace1[]. The divider cells have already
+  ** been removed from pParent.
+  **
+  ** If the siblings are on leaf pages, then the child pointers of the
+  ** divider cells are stripped from the cells before they are copied
+  ** into aSpace1[].  In this way, all cells in b.apCell[] are without
+  ** child pointers.  If siblings are not leaves, then all cell in
+  ** b.apCell[] include child pointers.  Either way, all cells in b.apCell[]
+  ** are alike.
+  **
+  ** leafCorrection:  4 if pPage is a leaf.  0 if pPage is not a leaf.
+  **       leafData:  1 if pPage holds key+data and pParent holds only keys.
+  */
+  b.pRef = apOld[0];
+  leafCorrection = b.pRef->leaf*4;
+  leafData = b.pRef->intKeyLeaf;
+  for(i=0; i<nOld; i++){
+    MemPage *pOld = apOld[i];
+    int limit = pOld->nCell;
+    u8 *aData = pOld->aData;
+    u16 maskPage = pOld->maskPage;
+    u8 *piCell = aData + pOld->cellOffset;
+    u8 *piEnd;
+    VVA_ONLY( int nCellAtStart = b.nCell; )
+
+    /* Verify that all sibling pages are of the same "type" (table-leaf,
+    ** table-interior, index-leaf, or index-interior).
+    */
+    if( pOld->aData[0]!=apOld[0]->aData[0] ){
+      rc = SQLITE_CORRUPT_PAGE(pOld);
+      goto balance_cleanup;
+    }
+
+    /* Load b.apCell[] with pointers to all cells in pOld.  If pOld
+    ** contains overflow cells, include them in the b.apCell[] array
+    ** in the correct spot.
+    **
+    ** Note that when there are multiple overflow cells, it is always the
+    ** case that they are sequential and adjacent.  This invariant arises
+    ** because multiple overflows can only occurs when inserting divider
+    ** cells into a parent on a prior balance, and divider cells are always
+    ** adjacent and are inserted in order.  There is an assert() tagged
+    ** with "NOTE 1" in the overflow cell insertion loop to prove this
+    ** invariant.
+    **
+    ** This must be done in advance.  Once the balance starts, the cell
+    ** offset section of the btree page will be overwritten and we will no
+    ** long be able to find the cells if a pointer to each cell is not saved
+    ** first.
+    */
+    memset(&b.szCell[b.nCell], 0, sizeof(b.szCell[0])*(limit+pOld->nOverflow));
+    if( pOld->nOverflow>0 ){
+      if( NEVER(limit<pOld->aiOvfl[0]) ){
+        rc = SQLITE_CORRUPT_PAGE(pOld);
+        goto balance_cleanup;
+      }
+      limit = pOld->aiOvfl[0];
+      for(j=0; j<limit; j++){
+        b.apCell[b.nCell] = aData + (maskPage & get2byteAligned(piCell));
+        piCell += 2;
+        b.nCell++;
+      }
+      for(k=0; k<pOld->nOverflow; k++){
+        assert( k==0 || pOld->aiOvfl[k-1]+1==pOld->aiOvfl[k] );/* NOTE 1 */
+        b.apCell[b.nCell] = pOld->apOvfl[k];
+        b.nCell++;
+      }
+    }
+    piEnd = aData + pOld->cellOffset + 2*pOld->nCell;
+    while( piCell<piEnd ){
+      assert( b.nCell<nMaxCells );
+      b.apCell[b.nCell] = aData + (maskPage & get2byteAligned(piCell));
+      piCell += 2;
+      b.nCell++;
+    }
+    assert( (b.nCell-nCellAtStart)==(pOld->nCell+pOld->nOverflow) );
+
+    cntOld[i] = b.nCell;
+    if( i<nOld-1 && !leafData){
+      u16 sz = (u16)szNew[i];
+      u8 *pTemp;
+      assert( b.nCell<nMaxCells );
+      b.szCell[b.nCell] = sz;
+      pTemp = &aSpace1[iSpace1];
+      iSpace1 += sz;
+      assert( sz<=pBt->maxLocal+23 );
+      assert( iSpace1 <= (int)pBt->pageSize );
+      memcpy(pTemp, apDiv[i], sz);
+      b.apCell[b.nCell] = pTemp+leafCorrection;
+      assert( leafCorrection==0 || leafCorrection==4 );
+      b.szCell[b.nCell] = b.szCell[b.nCell] - leafCorrection;
+      if( !pOld->leaf ){
+        assert( leafCorrection==0 );
+        assert( pOld->hdrOffset==0 || CORRUPT_DB );
+        /* The right pointer of the child page pOld becomes the left
+        ** pointer of the divider cell */
+        memcpy(b.apCell[b.nCell], &pOld->aData[8], 4);
+      }else{
+        assert( leafCorrection==4 );
+        while( b.szCell[b.nCell]<4 ){
+          /* Do not allow any cells smaller than 4 bytes. If a smaller cell
+          ** does exist, pad it with 0x00 bytes. */
+          assert( b.szCell[b.nCell]==3 || CORRUPT_DB );
+          assert( b.apCell[b.nCell]==&aSpace1[iSpace1-3] || CORRUPT_DB );
+          aSpace1[iSpace1++] = 0x00;
+          b.szCell[b.nCell]++;
+        }
+      }
+      b.nCell++;
+    }
+  }
+
+  /*
+  ** Figure out the number of pages needed to hold all b.nCell cells.
+  ** Store this number in "k".  Also compute szNew[] which is the total
+  ** size of all cells on the i-th page and cntNew[] which is the index
+  ** in b.apCell[] of the cell that divides page i from page i+1.
+  ** cntNew[k] should equal b.nCell.
+  **
+  ** Values computed by this block:
+  **
+  **           k: The total number of sibling pages
+  **    szNew[i]: Spaced used on the i-th sibling page.
+  **   cntNew[i]: Index in b.apCell[] and b.szCell[] for the first cell to
+  **              the right of the i-th sibling page.
+  ** usableSpace: Number of bytes of space available on each sibling.
+  **
+  */
+  usableSpace = pBt->usableSize - 12 + leafCorrection;
+  for(i=k=0; i<nOld; i++, k++){
+    MemPage *p = apOld[i];
+    b.apEnd[k] = p->aDataEnd;
+    b.ixNx[k] = cntOld[i];
+    if( k && b.ixNx[k]==b.ixNx[k-1] ){
+      k--;  /* Omit b.ixNx[] entry for child pages with no cells */
+    }
+    if( !leafData ){
+      k++;
+      b.apEnd[k] = pParent->aDataEnd;
+      b.ixNx[k] = cntOld[i]+1;
+    }
+    assert( p->nFree>=0 );
+    szNew[i] = usableSpace - p->nFree;
+    for(j=0; j<p->nOverflow; j++){
+      szNew[i] += 2 + p->xCellSize(p, p->apOvfl[j]);
+    }
+    cntNew[i] = cntOld[i];
+  }
+  k = nOld;
+  for(i=0; i<k; i++){
+    int sz;
+    while( szNew[i]>usableSpace ){
+      if( i+1>=k ){
+        k = i+2;
+        if( k>NB+2 ){ rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; }
+        szNew[k-1] = 0;
+        cntNew[k-1] = b.nCell;
+      }
+      sz = 2 + cachedCellSize(&b, cntNew[i]-1);
+      szNew[i] -= sz;
+      if( !leafData ){
+        if( cntNew[i]<b.nCell ){
+          sz = 2 + cachedCellSize(&b, cntNew[i]);
+        }else{
+          sz = 0;
+        }
+      }
+      szNew[i+1] += sz;
+      cntNew[i]--;
+    }
+    while( cntNew[i]<b.nCell ){
+      sz = 2 + cachedCellSize(&b, cntNew[i]);
+      if( szNew[i]+sz>usableSpace ) break;
+      szNew[i] += sz;
+      cntNew[i]++;
+      if( !leafData ){
+        if( cntNew[i]<b.nCell ){
+          sz = 2 + cachedCellSize(&b, cntNew[i]);
+        }else{
+          sz = 0;
+        }
+      }
+      szNew[i+1] -= sz;
+    }
+    if( cntNew[i]>=b.nCell ){
+      k = i+1;
+    }else if( cntNew[i] <= (i>0 ? cntNew[i-1] : 0) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto balance_cleanup;
+    }
+  }
+
+  /*
+  ** The packing computed by the previous block is biased toward the siblings
+  ** on the left side (siblings with smaller keys). The left siblings are
+  ** always nearly full, while the right-most sibling might be nearly empty.
+  ** The next block of code attempts to adjust the packing of siblings to
+  ** get a better balance.
+  **
+  ** This adjustment is more than an optimization.  The packing above might
+  ** be so out of balance as to be illegal.  For example, the right-most
+  ** sibling might be completely empty.  This adjustment is not optional.
+  */
+  for(i=k-1; i>0; i--){
+    int szRight = szNew[i];  /* Size of sibling on the right */
+    int szLeft = szNew[i-1]; /* Size of sibling on the left */
+    int r;              /* Index of right-most cell in left sibling */
+    int d;              /* Index of first cell to the left of right sibling */
+
+    r = cntNew[i-1] - 1;
+    d = r + 1 - leafData;
+    (void)cachedCellSize(&b, d);
+    do{
+      int szR, szD;
+      assert( d<nMaxCells );
+      assert( r<nMaxCells );
+      szR = cachedCellSize(&b, r);
+      szD = b.szCell[d];
+      if( szRight!=0
+       && (bBulk || szRight+szD+2 > szLeft-(szR+(i==k-1?0:2)))){
+        break;
+      }
+      szRight += szD + 2;
+      szLeft -= szR + 2;
+      cntNew[i-1] = r;
+      r--;
+      d--;
+    }while( r>=0 );
+    szNew[i] = szRight;
+    szNew[i-1] = szLeft;
+    if( cntNew[i-1] <= (i>1 ? cntNew[i-2] : 0) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto balance_cleanup;
+    }
+  }
+
+  /* Sanity check:  For a non-corrupt database file one of the following
+  ** must be true:
+  **    (1) We found one or more cells (cntNew[0])>0), or
+  **    (2) pPage is a virtual root page.  A virtual root page is when
+  **        the real root page is page 1 and we are the only child of
+  **        that page.
+  */
+  assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) || CORRUPT_DB);
+  TRACE(("BALANCE: old: %u(nc=%u) %u(nc=%u) %u(nc=%u)\n",
+    apOld[0]->pgno, apOld[0]->nCell,
+    nOld>=2 ? apOld[1]->pgno : 0, nOld>=2 ? apOld[1]->nCell : 0,
+    nOld>=3 ? apOld[2]->pgno : 0, nOld>=3 ? apOld[2]->nCell : 0
+  ));
+
+  /*
+  ** Allocate k new pages.  Reuse old pages where possible.
+  */
+  pageFlags = apOld[0]->aData[0];
+  for(i=0; i<k; i++){
+    MemPage *pNew;
+    if( i<nOld ){
+      pNew = apNew[i] = apOld[i];
+      apOld[i] = 0;
+      rc = sqlite3PagerWrite(pNew->pDbPage);
+      nNew++;
+      if( sqlite3PagerPageRefcount(pNew->pDbPage)!=1+(i==(iParentIdx-nxDiv))
+       && rc==SQLITE_OK
+      ){
+        rc = SQLITE_CORRUPT_BKPT;
+      }
+      if( rc ) goto balance_cleanup;
+    }else{
+      assert( i>0 );
+      rc = allocateBtreePage(pBt, &pNew, &pgno, (bBulk ? 1 : pgno), 0);
+      if( rc ) goto balance_cleanup;
+      zeroPage(pNew, pageFlags);
+      apNew[i] = pNew;
+      nNew++;
+      cntOld[i] = b.nCell;
+
+      /* Set the pointer-map entry for the new sibling page. */
+      if( ISAUTOVACUUM(pBt) ){
+        ptrmapPut(pBt, pNew->pgno, PTRMAP_BTREE, pParent->pgno, &rc);
+        if( rc!=SQLITE_OK ){
+          goto balance_cleanup;
+        }
+      }
+    }
+  }
+
+  /*
+  ** Reassign page numbers so that the new pages are in ascending order.
+  ** This helps to keep entries in the disk file in order so that a scan
+  ** of the table is closer to a linear scan through the file. That in turn
+  ** helps the operating system to deliver pages from the disk more rapidly.
+  **
+  ** An O(N*N) sort algorithm is used, but since N is never more than NB+2
+  ** (5), that is not a performance concern.
+  **
+  ** When NB==3, this one optimization makes the database about 25% faster
+  ** for large insertions and deletions.
+  */
+  for(i=0; i<nNew; i++){
+    aPgno[i] = apNew[i]->pgno;
+    assert( apNew[i]->pDbPage->flags & PGHDR_WRITEABLE );
+    assert( apNew[i]->pDbPage->flags & PGHDR_DIRTY );
+  }
+  for(i=0; i<nNew-1; i++){
+    int iB = i;
+    for(j=i+1; j<nNew; j++){
+      if( apNew[j]->pgno < apNew[iB]->pgno ) iB = j;
+    }
+
+    /* If apNew[i] has a page number that is bigger than any of the
+    ** subsequence apNew[i] entries, then swap apNew[i] with the subsequent
+    ** entry that has the smallest page number (which we know to be
+    ** entry apNew[iB]).
+    */
+    if( iB!=i ){
+      Pgno pgnoA = apNew[i]->pgno;
+      Pgno pgnoB = apNew[iB]->pgno;
+      Pgno pgnoTemp = (PENDING_BYTE/pBt->pageSize)+1;
+      u16 fgA = apNew[i]->pDbPage->flags;
+      u16 fgB = apNew[iB]->pDbPage->flags;
+      sqlite3PagerRekey(apNew[i]->pDbPage, pgnoTemp, fgB);
+      sqlite3PagerRekey(apNew[iB]->pDbPage, pgnoA, fgA);
+      sqlite3PagerRekey(apNew[i]->pDbPage, pgnoB, fgB);
+      apNew[i]->pgno = pgnoB;
+      apNew[iB]->pgno = pgnoA;
+    }
+  }
+
+  TRACE(("BALANCE: new: %u(%u nc=%u) %u(%u nc=%u) %u(%u nc=%u) "
+         "%u(%u nc=%u) %u(%u nc=%u)\n",
+    apNew[0]->pgno, szNew[0], cntNew[0],
+    nNew>=2 ? apNew[1]->pgno : 0, nNew>=2 ? szNew[1] : 0,
+    nNew>=2 ? cntNew[1] - cntNew[0] - !leafData : 0,
+    nNew>=3 ? apNew[2]->pgno : 0, nNew>=3 ? szNew[2] : 0,
+    nNew>=3 ? cntNew[2] - cntNew[1] - !leafData : 0,
+    nNew>=4 ? apNew[3]->pgno : 0, nNew>=4 ? szNew[3] : 0,
+    nNew>=4 ? cntNew[3] - cntNew[2] - !leafData : 0,
+    nNew>=5 ? apNew[4]->pgno : 0, nNew>=5 ? szNew[4] : 0,
+    nNew>=5 ? cntNew[4] - cntNew[3] - !leafData : 0
+  ));
+
+  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+  assert( nNew>=1 && nNew<=ArraySize(apNew) );
+  assert( apNew[nNew-1]!=0 );
+  put4byte(pRight, apNew[nNew-1]->pgno);
+
+  /* If the sibling pages are not leaves, ensure that the right-child pointer
+  ** of the right-most new sibling page is set to the value that was
+  ** originally in the same field of the right-most old sibling page. */
+  if( (pageFlags & PTF_LEAF)==0 && nOld!=nNew ){
+    MemPage *pOld = (nNew>nOld ? apNew : apOld)[nOld-1];
+    memcpy(&apNew[nNew-1]->aData[8], &pOld->aData[8], 4);
+  }
+
+  /* Make any required updates to pointer map entries associated with
+  ** cells stored on sibling pages following the balance operation. Pointer
+  ** map entries associated with divider cells are set by the insertCell()
+  ** routine. The associated pointer map entries are:
+  **
+  **   a) if the cell contains a reference to an overflow chain, the
+  **      entry associated with the first page in the overflow chain, and
+  **
+  **   b) if the sibling pages are not leaves, the child page associated
+  **      with the cell.
+  **
+  ** If the sibling pages are not leaves, then the pointer map entry
+  ** associated with the right-child of each sibling may also need to be
+  ** updated. This happens below, after the sibling pages have been
+  ** populated, not here.
+  */
+  if( ISAUTOVACUUM(pBt) ){
+    MemPage *pOld;
+    MemPage *pNew = pOld = apNew[0];
+    int cntOldNext = pNew->nCell + pNew->nOverflow;
+    int iNew = 0;
+    int iOld = 0;
+
+    for(i=0; i<b.nCell; i++){
+      u8 *pCell = b.apCell[i];
+      while( i==cntOldNext ){
+        iOld++;
+        assert( iOld<nNew || iOld<nOld );
+        assert( iOld>=0 && iOld<NB );
+        pOld = iOld<nNew ? apNew[iOld] : apOld[iOld];
+        cntOldNext += pOld->nCell + pOld->nOverflow + !leafData;
+      }
+      if( i==cntNew[iNew] ){
+        pNew = apNew[++iNew];
+        if( !leafData ) continue;
+      }
+
+      /* Cell pCell is destined for new sibling page pNew. Originally, it
+      ** was either part of sibling page iOld (possibly an overflow cell),
+      ** or else the divider cell to the left of sibling page iOld. So,
+      ** if sibling page iOld had the same page number as pNew, and if
+      ** pCell really was a part of sibling page iOld (not a divider or
+      ** overflow cell), we can skip updating the pointer map entries.  */
+      if( iOld>=nNew
+       || pNew->pgno!=aPgno[iOld]
+       || !SQLITE_WITHIN(pCell,pOld->aData,pOld->aDataEnd)
+      ){
+        if( !leafCorrection ){
+          ptrmapPut(pBt, get4byte(pCell), PTRMAP_BTREE, pNew->pgno, &rc);
+        }
+        if( cachedCellSize(&b,i)>pNew->minLocal ){
+          ptrmapPutOvflPtr(pNew, pOld, pCell, &rc);
+        }
+        if( rc ) goto balance_cleanup;
+      }
+    }
+  }
+
+  /* Insert new divider cells into pParent. */
+  for(i=0; i<nNew-1; i++){
+    u8 *pCell;
+    u8 *pTemp;
+    int sz;
+    u8 *pSrcEnd;
+    MemPage *pNew = apNew[i];
+    j = cntNew[i];
+
+    assert( j<nMaxCells );
+    assert( b.apCell[j]!=0 );
+    pCell = b.apCell[j];
+    sz = b.szCell[j] + leafCorrection;
+    pTemp = &aOvflSpace[iOvflSpace];
+    if( !pNew->leaf ){
+      memcpy(&pNew->aData[8], pCell, 4);
+    }else if( leafData ){
+      /* If the tree is a leaf-data tree, and the siblings are leaves,
+      ** then there is no divider cell in b.apCell[]. Instead, the divider
+      ** cell consists of the integer key for the right-most cell of
+      ** the sibling-page assembled above only.
+      */
+      CellInfo info;
+      j--;
+      pNew->xParseCell(pNew, b.apCell[j], &info);
+      pCell = pTemp;
+      sz = 4 + putVarint(&pCell[4], info.nKey);
+      pTemp = 0;
+    }else{
+      pCell -= 4;
+      /* Obscure case for non-leaf-data trees: If the cell at pCell was
+      ** previously stored on a leaf node, and its reported size was 4
+      ** bytes, then it may actually be smaller than this
+      ** (see btreeParseCellPtr(), 4 bytes is the minimum size of
+      ** any cell). But it is important to pass the correct size to
+      ** insertCell(), so reparse the cell now.
+      **
+      ** This can only happen for b-trees used to evaluate "IN (SELECT ...)"
+      ** and WITHOUT ROWID tables with exactly one column which is the
+      ** primary key.
+      */
+      if( b.szCell[j]==4 ){
+        assert(leafCorrection==4);
+        sz = pParent->xCellSize(pParent, pCell);
+      }
+    }
+    iOvflSpace += sz;
+    assert( sz<=pBt->maxLocal+23 );
+    assert( iOvflSpace <= (int)pBt->pageSize );
+    assert( b.ixNx[NB*2-1]>j );
+    for(k=0; b.ixNx[k]<=j; k++){}
+    pSrcEnd = b.apEnd[k];
+    if( SQLITE_OVERFLOW(pSrcEnd, pCell, pCell+sz) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto balance_cleanup;
+    }
+    rc = insertCell(pParent, nxDiv+i, pCell, sz, pTemp, pNew->pgno);
+    if( rc!=SQLITE_OK ) goto balance_cleanup;
+    assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+  }
+
+  /* Now update the actual sibling pages. The order in which they are updated
+  ** is important, as this code needs to avoid disrupting any page from which
+  ** cells may still to be read. In practice, this means:
+  **
+  **  (1) If cells are moving left (from apNew[iPg] to apNew[iPg-1])
+  **      then it is not safe to update page apNew[iPg] until after
+  **      the left-hand sibling apNew[iPg-1] has been updated.
+  **
+  **  (2) If cells are moving right (from apNew[iPg] to apNew[iPg+1])
+  **      then it is not safe to update page apNew[iPg] until after
+  **      the right-hand sibling apNew[iPg+1] has been updated.
+  **
+  ** If neither of the above apply, the page is safe to update.
+  **
+  ** The iPg value in the following loop starts at nNew-1 goes down
+  ** to 0, then back up to nNew-1 again, thus making two passes over
+  ** the pages.  On the initial downward pass, only condition (1) above
+  ** needs to be tested because (2) will always be true from the previous
+  ** step.  On the upward pass, both conditions are always true, so the
+  ** upwards pass simply processes pages that were missed on the downward
+  ** pass.
+  */
+  for(i=1-nNew; i<nNew; i++){
+    int iPg = i<0 ? -i : i;
+    assert( iPg>=0 && iPg<nNew );
+    assert( iPg>=1 || i>=0 );
+    assert( iPg<ArraySize(cntOld) );
+    if( abDone[iPg] ) continue;         /* Skip pages already processed */
+    if( i>=0                            /* On the upwards pass, or... */
+     || cntOld[iPg-1]>=cntNew[iPg-1]    /* Condition (1) is true */
+    ){
+      int iNew;
+      int iOld;
+      int nNewCell;
+
+      /* Verify condition (1):  If cells are moving left, update iPg
+      ** only after iPg-1 has already been updated. */
+      assert( iPg==0 || cntOld[iPg-1]>=cntNew[iPg-1] || abDone[iPg-1] );
+
+      /* Verify condition (2):  If cells are moving right, update iPg
+      ** only after iPg+1 has already been updated. */
+      assert( cntNew[iPg]>=cntOld[iPg] || abDone[iPg+1] );
+
+      if( iPg==0 ){
+        iNew = iOld = 0;
+        nNewCell = cntNew[0];
+      }else{
+        iOld = iPg<nOld ? (cntOld[iPg-1] + !leafData) : b.nCell;
+        iNew = cntNew[iPg-1] + !leafData;
+        nNewCell = cntNew[iPg] - iNew;
+      }
+
+      rc = editPage(apNew[iPg], iOld, iNew, nNewCell, &b);
+      if( rc ) goto balance_cleanup;
+      abDone[iPg]++;
+      apNew[iPg]->nFree = usableSpace-szNew[iPg];
+      assert( apNew[iPg]->nOverflow==0 );
+      assert( apNew[iPg]->nCell==nNewCell );
+    }
+  }
+
+  /* All pages have been processed exactly once */
+  assert( memcmp(abDone, "\01\01\01\01\01", nNew)==0 );
+
+  assert( nOld>0 );
+  assert( nNew>0 );
+
+  if( isRoot && pParent->nCell==0 && pParent->hdrOffset<=apNew[0]->nFree ){
+    /* The root page of the b-tree now contains no cells. The only sibling
+    ** page is the right-child of the parent. Copy the contents of the
+    ** child page into the parent, decreasing the overall height of the
+    ** b-tree structure by one. This is described as the "balance-shallower"
+    ** sub-algorithm in some documentation.
+    **
+    ** If this is an auto-vacuum database, the call to copyNodeContent()
+    ** sets all pointer-map entries corresponding to database image pages
+    ** for which the pointer is stored within the content being copied.
+    **
+    ** It is critical that the child page be defragmented before being
+    ** copied into the parent, because if the parent is page 1 then it will
+    ** by smaller than the child due to the database header, and so all the
+    ** free space needs to be up front.
+    */
+    assert( nNew==1 || CORRUPT_DB );
+    rc = defragmentPage(apNew[0], -1);
+    testcase( rc!=SQLITE_OK );
+    assert( apNew[0]->nFree ==
+        (get2byteNotZero(&apNew[0]->aData[5]) - apNew[0]->cellOffset
+          - apNew[0]->nCell*2)
+      || rc!=SQLITE_OK
+    );
+    copyNodeContent(apNew[0], pParent, &rc);
+    freePage(apNew[0], &rc);
+  }else if( ISAUTOVACUUM(pBt) && !leafCorrection ){
+    /* Fix the pointer map entries associated with the right-child of each
+    ** sibling page. All other pointer map entries have already been taken
+    ** care of.  */
+    for(i=0; i<nNew; i++){
+      u32 key = get4byte(&apNew[i]->aData[8]);
+      ptrmapPut(pBt, key, PTRMAP_BTREE, apNew[i]->pgno, &rc);
+    }
+  }
+
+  assert( pParent->isInit );
+  TRACE(("BALANCE: finished: old=%u new=%u cells=%u\n",
+          nOld, nNew, b.nCell));
+
+  /* Free any old pages that were not reused as new pages.
+  */
+  for(i=nNew; i<nOld; i++){
+    freePage(apOld[i], &rc);
+  }
+
+#if 0
+  if( ISAUTOVACUUM(pBt) && rc==SQLITE_OK && apNew[0]->isInit ){
+    /* The ptrmapCheckPages() contains assert() statements that verify that
+    ** all pointer map pages are set correctly. This is helpful while
+    ** debugging. This is usually disabled because a corrupt database may
+    ** cause an assert() statement to fail.  */
+    ptrmapCheckPages(apNew, nNew);
+    ptrmapCheckPages(&pParent, 1);
+  }
+#endif
+
+  /*
+  ** Cleanup before returning.
+  */
+balance_cleanup:
+  sqlite3StackFree(0, b.apCell);
+  for(i=0; i<nOld; i++){
+    releasePage(apOld[i]);
+  }
+  for(i=0; i<nNew; i++){
+    releasePage(apNew[i]);
+  }
+
+  return rc;
+}
+
+
+/*
+** This function is called when the root page of a b-tree structure is
+** overfull (has one or more overflow pages).
+**
+** A new child page is allocated and the contents of the current root
+** page, including overflow cells, are copied into the child. The root
+** page is then overwritten to make it an empty page with the right-child
+** pointer pointing to the new page.
+**
+** Before returning, all pointer-map entries corresponding to pages
+** that the new child-page now contains pointers to are updated. The
+** entry corresponding to the new right-child pointer of the root
+** page is also updated.
+**
+** If successful, *ppChild is set to contain a reference to the child
+** page and SQLITE_OK is returned. In this case the caller is required
+** to call releasePage() on *ppChild exactly once. If an error occurs,
+** an error code is returned and *ppChild is set to 0.
+*/
+static int balance_deeper(MemPage *pRoot, MemPage **ppChild){
+  int rc;                        /* Return value from subprocedures */
+  MemPage *pChild = 0;           /* Pointer to a new child page */
+  Pgno pgnoChild = 0;            /* Page number of the new child page */
+  BtShared *pBt = pRoot->pBt;    /* The BTree */
+
+  assert( pRoot->nOverflow>0 );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+
+  /* Make pRoot, the root page of the b-tree, writable. Allocate a new
+  ** page that will become the new right-child of pPage. Copy the contents
+  ** of the node stored on pRoot into the new child page.
+  */
+  rc = sqlite3PagerWrite(pRoot->pDbPage);
+  if( rc==SQLITE_OK ){
+    rc = allocateBtreePage(pBt,&pChild,&pgnoChild,pRoot->pgno,0);
+    copyNodeContent(pRoot, pChild, &rc);
+    if( ISAUTOVACUUM(pBt) ){
+      ptrmapPut(pBt, pgnoChild, PTRMAP_BTREE, pRoot->pgno, &rc);
+    }
+  }
+  if( rc ){
+    *ppChild = 0;
+    releasePage(pChild);
+    return rc;
+  }
+  assert( sqlite3PagerIswriteable(pChild->pDbPage) );
+  assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
+  assert( pChild->nCell==pRoot->nCell || CORRUPT_DB );
+
+  TRACE(("BALANCE: copy root %u into %u\n", pRoot->pgno, pChild->pgno));
+
+  /* Copy the overflow cells from pRoot to pChild */
+  memcpy(pChild->aiOvfl, pRoot->aiOvfl,
+         pRoot->nOverflow*sizeof(pRoot->aiOvfl[0]));
+  memcpy(pChild->apOvfl, pRoot->apOvfl,
+         pRoot->nOverflow*sizeof(pRoot->apOvfl[0]));
+  pChild->nOverflow = pRoot->nOverflow;
+
+  /* Zero the contents of pRoot. Then install pChild as the right-child. */
+  zeroPage(pRoot, pChild->aData[0] & ~PTF_LEAF);
+  put4byte(&pRoot->aData[pRoot->hdrOffset+8], pgnoChild);
+
+  *ppChild = pChild;
+  return SQLITE_OK;
+}
+
+/*
+** Return SQLITE_CORRUPT if any cursor other than pCur is currently valid
+** on the same B-tree as pCur.
+**
+** This can occur if a database is corrupt with two or more SQL tables
+** pointing to the same b-tree.  If an insert occurs on one SQL table
+** and causes a BEFORE TRIGGER to do a secondary insert on the other SQL
+** table linked to the same b-tree.  If the secondary insert causes a
+** rebalance, that can change content out from under the cursor on the
+** first SQL table, violating invariants on the first insert.
+*/
+static int anotherValidCursor(BtCursor *pCur){
+  BtCursor *pOther;
+  for(pOther=pCur->pBt->pCursor; pOther; pOther=pOther->pNext){
+    if( pOther!=pCur
+     && pOther->eState==CURSOR_VALID
+     && pOther->pPage==pCur->pPage
+    ){
+      return SQLITE_CORRUPT_PAGE(pCur->pPage);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The page that pCur currently points to has just been modified in
+** some way. This function figures out if this modification means the
+** tree needs to be balanced, and if so calls the appropriate balancing
+** routine. Balancing routines are:
+**
+**   balance_quick()
+**   balance_deeper()
+**   balance_nonroot()
+*/
+static int balance(BtCursor *pCur){
+  int rc = SQLITE_OK;
+  u8 aBalanceQuickSpace[13];
+  u8 *pFree = 0;
+
+  VVA_ONLY( int balance_quick_called = 0 );
+  VVA_ONLY( int balance_deeper_called = 0 );
+
+  do {
+    int iPage;
+    MemPage *pPage = pCur->pPage;
+
+    if( NEVER(pPage->nFree<0) && btreeComputeFreeSpace(pPage) ) break;
+    if( pPage->nOverflow==0 && pPage->nFree*3<=(int)pCur->pBt->usableSize*2 ){
+      /* No rebalance required as long as:
+      **   (1) There are no overflow cells
+      **   (2) The amount of free space on the page is less than 2/3rds of
+      **       the total usable space on the page. */
+      break;
+    }else if( (iPage = pCur->iPage)==0 ){
+      if( pPage->nOverflow && (rc = anotherValidCursor(pCur))==SQLITE_OK ){
+        /* The root page of the b-tree is overfull. In this case call the
+        ** balance_deeper() function to create a new child for the root-page
+        ** and copy the current contents of the root-page to it. The
+        ** next iteration of the do-loop will balance the child page.
+        */
+        assert( balance_deeper_called==0 );
+        VVA_ONLY( balance_deeper_called++ );
+        rc = balance_deeper(pPage, &pCur->apPage[1]);
+        if( rc==SQLITE_OK ){
+          pCur->iPage = 1;
+          pCur->ix = 0;
+          pCur->aiIdx[0] = 0;
+          pCur->apPage[0] = pPage;
+          pCur->pPage = pCur->apPage[1];
+          assert( pCur->pPage->nOverflow );
+        }
+      }else{
+        break;
+      }
+    }else if( sqlite3PagerPageRefcount(pPage->pDbPage)>1 ){
+      /* The page being written is not a root page, and there is currently
+      ** more than one reference to it. This only happens if the page is one
+      ** of its own ancestor pages. Corruption. */
+      rc = SQLITE_CORRUPT_PAGE(pPage);
+    }else{
+      MemPage * const pParent = pCur->apPage[iPage-1];
+      int const iIdx = pCur->aiIdx[iPage-1];
+
+      rc = sqlite3PagerWrite(pParent->pDbPage);
+      if( rc==SQLITE_OK && pParent->nFree<0 ){
+        rc = btreeComputeFreeSpace(pParent);
+      }
+      if( rc==SQLITE_OK ){
+#ifndef SQLITE_OMIT_QUICKBALANCE
+        if( pPage->intKeyLeaf
+         && pPage->nOverflow==1
+         && pPage->aiOvfl[0]==pPage->nCell
+         && pParent->pgno!=1
+         && pParent->nCell==iIdx
+        ){
+          /* Call balance_quick() to create a new sibling of pPage on which
+          ** to store the overflow cell. balance_quick() inserts a new cell
+          ** into pParent, which may cause pParent overflow. If this
+          ** happens, the next iteration of the do-loop will balance pParent
+          ** use either balance_nonroot() or balance_deeper(). Until this
+          ** happens, the overflow cell is stored in the aBalanceQuickSpace[]
+          ** buffer.
+          **
+          ** The purpose of the following assert() is to check that only a
+          ** single call to balance_quick() is made for each call to this
+          ** function. If this were not verified, a subtle bug involving reuse
+          ** of the aBalanceQuickSpace[] might sneak in.
+          */
+          assert( balance_quick_called==0 );
+          VVA_ONLY( balance_quick_called++ );
+          rc = balance_quick(pParent, pPage, aBalanceQuickSpace);
+        }else
+#endif
+        {
+          /* In this case, call balance_nonroot() to redistribute cells
+          ** between pPage and up to 2 of its sibling pages. This involves
+          ** modifying the contents of pParent, which may cause pParent to
+          ** become overfull or underfull. The next iteration of the do-loop
+          ** will balance the parent page to correct this.
+          **
+          ** If the parent page becomes overfull, the overflow cell or cells
+          ** are stored in the pSpace buffer allocated immediately below.
+          ** A subsequent iteration of the do-loop will deal with this by
+          ** calling balance_nonroot() (balance_deeper() may be called first,
+          ** but it doesn't deal with overflow cells - just moves them to a
+          ** different page). Once this subsequent call to balance_nonroot()
+          ** has completed, it is safe to release the pSpace buffer used by
+          ** the previous call, as the overflow cell data will have been
+          ** copied either into the body of a database page or into the new
+          ** pSpace buffer passed to the latter call to balance_nonroot().
+          */
+          u8 *pSpace = sqlite3PageMalloc(pCur->pBt->pageSize);
+          rc = balance_nonroot(pParent, iIdx, pSpace, iPage==1,
+                               pCur->hints&BTREE_BULKLOAD);
+          if( pFree ){
+            /* If pFree is not NULL, it points to the pSpace buffer used
+            ** by a previous call to balance_nonroot(). Its contents are
+            ** now stored either on real database pages or within the
+            ** new pSpace buffer, so it may be safely freed here. */
+            sqlite3PageFree(pFree);
+          }
+
+          /* The pSpace buffer will be freed after the next call to
+          ** balance_nonroot(), or just before this function returns, whichever
+          ** comes first. */
+          pFree = pSpace;
+        }
+      }
+
+      pPage->nOverflow = 0;
+
+      /* The next iteration of the do-loop balances the parent page. */
+      releasePage(pPage);
+      pCur->iPage--;
+      assert( pCur->iPage>=0 );
+      pCur->pPage = pCur->apPage[pCur->iPage];
+    }
+  }while( rc==SQLITE_OK );
+
+  if( pFree ){
+    sqlite3PageFree(pFree);
+  }
+  return rc;
+}
+
+/* Overwrite content from pX into pDest.  Only do the write if the
+** content is different from what is already there.
+*/
+static int btreeOverwriteContent(
+  MemPage *pPage,           /* MemPage on which writing will occur */
+  u8 *pDest,                /* Pointer to the place to start writing */
+  const BtreePayload *pX,   /* Source of data to write */
+  int iOffset,              /* Offset of first byte to write */
+  int iAmt                  /* Number of bytes to be written */
+){
+  int nData = pX->nData - iOffset;
+  if( nData<=0 ){
+    /* Overwriting with zeros */
+    int i;
+    for(i=0; i<iAmt && pDest[i]==0; i++){}
+    if( i<iAmt ){
+      int rc = sqlite3PagerWrite(pPage->pDbPage);
+      if( rc ) return rc;
+      memset(pDest + i, 0, iAmt - i);
+    }
+  }else{
+    if( nData<iAmt ){
+      /* Mixed read data and zeros at the end.  Make a recursive call
+      ** to write the zeros then fall through to write the real data */
+      int rc = btreeOverwriteContent(pPage, pDest+nData, pX, iOffset+nData,
+                                 iAmt-nData);
+      if( rc ) return rc;
+      iAmt = nData;
+    }
+    if( memcmp(pDest, ((u8*)pX->pData) + iOffset, iAmt)!=0 ){
+      int rc = sqlite3PagerWrite(pPage->pDbPage);
+      if( rc ) return rc;
+      /* In a corrupt database, it is possible for the source and destination
+      ** buffers to overlap.  This is harmless since the database is already
+      ** corrupt but it does cause valgrind and ASAN warnings.  So use
+      ** memmove(). */
+      memmove(pDest, ((u8*)pX->pData) + iOffset, iAmt);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Overwrite the cell that cursor pCur is pointing to with fresh content
+** contained in pX.  In this variant, pCur is pointing to an overflow
+** cell.
+*/
+static SQLITE_NOINLINE int btreeOverwriteOverflowCell(
+  BtCursor *pCur,                     /* Cursor pointing to cell to overwrite */
+  const BtreePayload *pX              /* Content to write into the cell */
+){
+  int iOffset;                        /* Next byte of pX->pData to write */
+  int nTotal = pX->nData + pX->nZero; /* Total bytes of to write */
+  int rc;                             /* Return code */
+  MemPage *pPage = pCur->pPage;       /* Page being written */
+  BtShared *pBt;                      /* Btree */
+  Pgno ovflPgno;                      /* Next overflow page to write */
+  u32 ovflPageSize;                   /* Size to write on overflow page */
+
+  assert( pCur->info.nLocal<nTotal );  /* pCur is an overflow cell */
+
+  /* Overwrite the local portion first */
+  rc = btreeOverwriteContent(pPage, pCur->info.pPayload, pX,
+                             0, pCur->info.nLocal);
+  if( rc ) return rc;
+
+  /* Now overwrite the overflow pages */
+  iOffset = pCur->info.nLocal;
+  assert( nTotal>=0 );
+  assert( iOffset>=0 );
+  ovflPgno = get4byte(pCur->info.pPayload + iOffset);
+  pBt = pPage->pBt;
+  ovflPageSize = pBt->usableSize - 4;
+  do{
+    rc = btreeGetPage(pBt, ovflPgno, &pPage, 0);
+    if( rc ) return rc;
+    if( sqlite3PagerPageRefcount(pPage->pDbPage)!=1 || pPage->isInit ){
+      rc = SQLITE_CORRUPT_PAGE(pPage);
+    }else{
+      if( iOffset+ovflPageSize<(u32)nTotal ){
+        ovflPgno = get4byte(pPage->aData);
+      }else{
+        ovflPageSize = nTotal - iOffset;
+      }
+      rc = btreeOverwriteContent(pPage, pPage->aData+4, pX,
+                                 iOffset, ovflPageSize);
+    }
+    sqlite3PagerUnref(pPage->pDbPage);
+    if( rc ) return rc;
+    iOffset += ovflPageSize;
+  }while( iOffset<nTotal );
+  return SQLITE_OK;
+}
+
+/*
+** Overwrite the cell that cursor pCur is pointing to with fresh content
+** contained in pX.
+*/
+static int btreeOverwriteCell(BtCursor *pCur, const BtreePayload *pX){
+  int nTotal = pX->nData + pX->nZero; /* Total bytes of to write */
+  MemPage *pPage = pCur->pPage;       /* Page being written */
+
+  if( pCur->info.pPayload + pCur->info.nLocal > pPage->aDataEnd
+   || pCur->info.pPayload < pPage->aData + pPage->cellOffset
+  ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  if( pCur->info.nLocal==nTotal ){
+    /* The entire cell is local */
+    return btreeOverwriteContent(pPage, pCur->info.pPayload, pX,
+                                 0, pCur->info.nLocal);
+  }else{
+    /* The cell contains overflow content */
+    return btreeOverwriteOverflowCell(pCur, pX);
+  }
+}
+
+
+/*
+** Insert a new record into the BTree.  The content of the new record
+** is described by the pX object.  The pCur cursor is used only to
+** define what table the record should be inserted into, and is left
+** pointing at a random location.
+**
+** For a table btree (used for rowid tables), only the pX.nKey value of
+** the key is used. The pX.pKey value must be NULL.  The pX.nKey is the
+** rowid or INTEGER PRIMARY KEY of the row.  The pX.nData,pData,nZero fields
+** hold the content of the row.
+**
+** For an index btree (used for indexes and WITHOUT ROWID tables), the
+** key is an arbitrary byte sequence stored in pX.pKey,nKey.  The
+** pX.pData,nData,nZero fields must be zero.
+**
+** If the seekResult parameter is non-zero, then a successful call to
+** sqlite3BtreeIndexMoveto() to seek cursor pCur to (pKey,nKey) has already
+** been performed.  In other words, if seekResult!=0 then the cursor
+** is currently pointing to a cell that will be adjacent to the cell
+** to be inserted.  If seekResult<0 then pCur points to a cell that is
+** smaller then (pKey,nKey).  If seekResult>0 then pCur points to a cell
+** that is larger than (pKey,nKey).
+**
+** If seekResult==0, that means pCur is pointing at some unknown location.
+** In that case, this routine must seek the cursor to the correct insertion
+** point for (pKey,nKey) before doing the insertion.  For index btrees,
+** if pX->nMem is non-zero, then pX->aMem contains pointers to the unpacked
+** key values and pX->aMem can be used instead of pX->pKey to avoid having
+** to decode the key.
+*/
+SQLITE_PRIVATE int sqlite3BtreeInsert(
+  BtCursor *pCur,                /* Insert data into the table of this cursor */
+  const BtreePayload *pX,        /* Content of the row to be inserted */
+  int flags,                     /* True if this is likely an append */
+  int seekResult                 /* Result of prior IndexMoveto() call */
+){
+  int rc;
+  int loc = seekResult;          /* -1: before desired location  +1: after */
+  int szNew = 0;
+  int idx;
+  MemPage *pPage;
+  Btree *p = pCur->pBtree;
+  unsigned char *oldCell;
+  unsigned char *newCell = 0;
+
+  assert( (flags & (BTREE_SAVEPOSITION|BTREE_APPEND|BTREE_PREFORMAT))==flags );
+  assert( (flags & BTREE_PREFORMAT)==0 || seekResult || pCur->pKeyInfo==0 );
+
+  /* Save the positions of any other cursors open on this table.
+  **
+  ** In some cases, the call to btreeMoveto() below is a no-op. For
+  ** example, when inserting data into a table with auto-generated integer
+  ** keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the
+  ** integer key to use. It then calls this function to actually insert the
+  ** data into the intkey B-Tree. In this case btreeMoveto() recognizes
+  ** that the cursor is already where it needs to be and returns without
+  ** doing any work. To avoid thwarting these optimizations, it is important
+  ** not to clear the cursor here.
+  */
+  if( pCur->curFlags & BTCF_Multiple ){
+    rc = saveAllCursors(p->pBt, pCur->pgnoRoot, pCur);
+    if( rc ) return rc;
+    if( loc && pCur->iPage<0 ){
+      /* This can only happen if the schema is corrupt such that there is more
+      ** than one table or index with the same root page as used by the cursor.
+      ** Which can only happen if the SQLITE_NoSchemaError flag was set when
+      ** the schema was loaded. This cannot be asserted though, as a user might
+      ** set the flag, load the schema, and then unset the flag.  */
+      return SQLITE_CORRUPT_PGNO(pCur->pgnoRoot);
+    }
+  }
+
+  /* Ensure that the cursor is not in the CURSOR_FAULT state and that it
+  ** points to a valid cell.
+  */
+  if( pCur->eState>=CURSOR_REQUIRESEEK ){
+    testcase( pCur->eState==CURSOR_REQUIRESEEK );
+    testcase( pCur->eState==CURSOR_FAULT );
+    rc = moveToRoot(pCur);
+    if( rc && rc!=SQLITE_EMPTY ) return rc;
+  }
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( (pCur->curFlags & BTCF_WriteFlag)!=0
+              && p->pBt->inTransaction==TRANS_WRITE
+              && (p->pBt->btsFlags & BTS_READ_ONLY)==0 );
+  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
+
+  /* Assert that the caller has been consistent. If this cursor was opened
+  ** expecting an index b-tree, then the caller should be inserting blob
+  ** keys with no associated data. If the cursor was opened expecting an
+  ** intkey table, the caller should be inserting integer keys with a
+  ** blob of associated data.  */
+  assert( (flags & BTREE_PREFORMAT) || (pX->pKey==0)==(pCur->pKeyInfo==0) );
+
+  if( pCur->pKeyInfo==0 ){
+    assert( pX->pKey==0 );
+    /* If this is an insert into a table b-tree, invalidate any incrblob
+    ** cursors open on the row being replaced */
+    if( p->hasIncrblobCur ){
+      invalidateIncrblobCursors(p, pCur->pgnoRoot, pX->nKey, 0);
+    }
+
+    /* If BTREE_SAVEPOSITION is set, the cursor must already be pointing
+    ** to a row with the same key as the new entry being inserted.
+    */
+#ifdef SQLITE_DEBUG
+    if( flags & BTREE_SAVEPOSITION ){
+      assert( pCur->curFlags & BTCF_ValidNKey );
+      assert( pX->nKey==pCur->info.nKey );
+      assert( loc==0 );
+    }
+#endif
+
+    /* On the other hand, BTREE_SAVEPOSITION==0 does not imply
+    ** that the cursor is not pointing to a row to be overwritten.
+    ** So do a complete check.
+    */
+    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && pX->nKey==pCur->info.nKey ){
+      /* The cursor is pointing to the entry that is to be
+      ** overwritten */
+      assert( pX->nData>=0 && pX->nZero>=0 );
+      if( pCur->info.nSize!=0
+       && pCur->info.nPayload==(u32)pX->nData+pX->nZero
+      ){
+        /* New entry is the same size as the old.  Do an overwrite */
+        return btreeOverwriteCell(pCur, pX);
+      }
+      assert( loc==0 );
+    }else if( loc==0 ){
+      /* The cursor is *not* pointing to the cell to be overwritten, nor
+      ** to an adjacent cell.  Move the cursor so that it is pointing either
+      ** to the cell to be overwritten or an adjacent cell.
+      */
+      rc = sqlite3BtreeTableMoveto(pCur, pX->nKey,
+               (flags & BTREE_APPEND)!=0, &loc);
+      if( rc ) return rc;
+    }
+  }else{
+    /* This is an index or a WITHOUT ROWID table */
+
+    /* If BTREE_SAVEPOSITION is set, the cursor must already be pointing
+    ** to a row with the same key as the new entry being inserted.
+    */
+    assert( (flags & BTREE_SAVEPOSITION)==0 || loc==0 );
+
+    /* If the cursor is not already pointing either to the cell to be
+    ** overwritten, or if a new cell is being inserted, if the cursor is
+    ** not pointing to an immediately adjacent cell, then move the cursor
+    ** so that it does.
+    */
+    if( loc==0 && (flags & BTREE_SAVEPOSITION)==0 ){
+      if( pX->nMem ){
+        UnpackedRecord r;
+        r.pKeyInfo = pCur->pKeyInfo;
+        r.aMem = pX->aMem;
+        r.nField = pX->nMem;
+        r.default_rc = 0;
+        r.eqSeen = 0;
+        rc = sqlite3BtreeIndexMoveto(pCur, &r, &loc);
+      }else{
+        rc = btreeMoveto(pCur, pX->pKey, pX->nKey,
+                    (flags & BTREE_APPEND)!=0, &loc);
+      }
+      if( rc ) return rc;
+    }
+
+    /* If the cursor is currently pointing to an entry to be overwritten
+    ** and the new content is the same as as the old, then use the
+    ** overwrite optimization.
+    */
+    if( loc==0 ){
+      getCellInfo(pCur);
+      if( pCur->info.nKey==pX->nKey ){
+        BtreePayload x2;
+        x2.pData = pX->pKey;
+        x2.nData = pX->nKey;
+        x2.nZero = 0;
+        return btreeOverwriteCell(pCur, &x2);
+      }
+    }
+  }
+  assert( pCur->eState==CURSOR_VALID
+       || (pCur->eState==CURSOR_INVALID && loc) || CORRUPT_DB );
+
+  pPage = pCur->pPage;
+  assert( pPage->intKey || pX->nKey>=0 || (flags & BTREE_PREFORMAT) );
+  assert( pPage->leaf || !pPage->intKey );
+  if( pPage->nFree<0 ){
+    if( NEVER(pCur->eState>CURSOR_INVALID) ){
+     /* ^^^^^--- due to the moveToRoot() call above */
+      rc = SQLITE_CORRUPT_PAGE(pPage);
+    }else{
+      rc = btreeComputeFreeSpace(pPage);
+    }
+    if( rc ) return rc;
+  }
+
+  TRACE(("INSERT: table=%u nkey=%lld ndata=%u page=%u %s\n",
+          pCur->pgnoRoot, pX->nKey, pX->nData, pPage->pgno,
+          loc==0 ? "overwrite" : "new entry"));
+  assert( pPage->isInit || CORRUPT_DB );
+  newCell = p->pBt->pTmpSpace;
+  assert( newCell!=0 );
+  assert( BTREE_PREFORMAT==OPFLAG_PREFORMAT );
+  if( flags & BTREE_PREFORMAT ){
+    rc = SQLITE_OK;
+    szNew = p->pBt->nPreformatSize;
+    if( szNew<4 ){
+      szNew = 4;
+      newCell[3] = 0;
+    }
+    if( ISAUTOVACUUM(p->pBt) && szNew>pPage->maxLocal ){
+      CellInfo info;
+      pPage->xParseCell(pPage, newCell, &info);
+      if( info.nPayload!=info.nLocal ){
+        Pgno ovfl = get4byte(&newCell[szNew-4]);
+        ptrmapPut(p->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, &rc);
+        if( NEVER(rc) ) goto end_insert;
+      }
+    }
+  }else{
+    rc = fillInCell(pPage, newCell, pX, &szNew);
+    if( rc ) goto end_insert;
+  }
+  assert( szNew==pPage->xCellSize(pPage, newCell) );
+  assert( szNew <= MX_CELL_SIZE(p->pBt) );
+  idx = pCur->ix;
+  pCur->info.nSize = 0;
+  if( loc==0 ){
+    CellInfo info;
+    assert( idx>=0 );
+    if( idx>=pPage->nCell ){
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( rc ){
+      goto end_insert;
+    }
+    oldCell = findCell(pPage, idx);
+    if( !pPage->leaf ){
+      memcpy(newCell, oldCell, 4);
+    }
+    BTREE_CLEAR_CELL(rc, pPage, oldCell, info);
+    testcase( pCur->curFlags & BTCF_ValidOvfl );
+    invalidateOverflowCache(pCur);
+    if( info.nSize==szNew && info.nLocal==info.nPayload
+     && (!ISAUTOVACUUM(p->pBt) || szNew<pPage->minLocal)
+    ){
+      /* Overwrite the old cell with the new if they are the same size.
+      ** We could also try to do this if the old cell is smaller, then add
+      ** the leftover space to the free list.  But experiments show that
+      ** doing that is no faster then skipping this optimization and just
+      ** calling dropCell() and insertCell().
+      **
+      ** This optimization cannot be used on an autovacuum database if the
+      ** new entry uses overflow pages, as the insertCell() call below is
+      ** necessary to add the PTRMAP_OVERFLOW1 pointer-map entry.  */
+      assert( rc==SQLITE_OK ); /* clearCell never fails when nLocal==nPayload */
+      if( oldCell < pPage->aData+pPage->hdrOffset+10 ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      if( oldCell+szNew > pPage->aDataEnd ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      memcpy(oldCell, newCell, szNew);
+      return SQLITE_OK;
+    }
+    dropCell(pPage, idx, info.nSize, &rc);
+    if( rc ) goto end_insert;
+  }else if( loc<0 && pPage->nCell>0 ){
+    assert( pPage->leaf );
+    idx = ++pCur->ix;
+    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+  }else{
+    assert( pPage->leaf );
+  }
+  rc = insertCellFast(pPage, idx, newCell, szNew);
+  assert( pPage->nOverflow==0 || rc==SQLITE_OK );
+  assert( rc!=SQLITE_OK || pPage->nCell>0 || pPage->nOverflow>0 );
+
+  /* If no error has occurred and pPage has an overflow cell, call balance()
+  ** to redistribute the cells within the tree. Since balance() may move
+  ** the cursor, zero the BtCursor.info.nSize and BTCF_ValidNKey
+  ** variables.
+  **
+  ** Previous versions of SQLite called moveToRoot() to move the cursor
+  ** back to the root page as balance() used to invalidate the contents
+  ** of BtCursor.apPage[] and BtCursor.aiIdx[]. Instead of doing that,
+  ** set the cursor state to "invalid". This makes common insert operations
+  ** slightly faster.
+  **
+  ** There is a subtle but important optimization here too. When inserting
+  ** multiple records into an intkey b-tree using a single cursor (as can
+  ** happen while processing an "INSERT INTO ... SELECT" statement), it
+  ** is advantageous to leave the cursor pointing to the last entry in
+  ** the b-tree if possible. If the cursor is left pointing to the last
+  ** entry in the table, and the next row inserted has an integer key
+  ** larger than the largest existing key, it is possible to insert the
+  ** row without seeking the cursor. This can be a big performance boost.
+  */
+  if( pPage->nOverflow ){
+    assert( rc==SQLITE_OK );
+    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+    rc = balance(pCur);
+
+    /* Must make sure nOverflow is reset to zero even if the balance()
+    ** fails. Internal data structure corruption will result otherwise.
+    ** Also, set the cursor state to invalid. This stops saveCursorPosition()
+    ** from trying to save the current position of the cursor.  */
+    pCur->pPage->nOverflow = 0;
+    pCur->eState = CURSOR_INVALID;
+    if( (flags & BTREE_SAVEPOSITION) && rc==SQLITE_OK ){
+      btreeReleaseAllCursorPages(pCur);
+      if( pCur->pKeyInfo ){
+        assert( pCur->pKey==0 );
+        pCur->pKey = sqlite3Malloc( pX->nKey );
+        if( pCur->pKey==0 ){
+          rc = SQLITE_NOMEM;
+        }else{
+          memcpy(pCur->pKey, pX->pKey, pX->nKey);
+        }
+      }
+      pCur->eState = CURSOR_REQUIRESEEK;
+      pCur->nKey = pX->nKey;
+    }
+  }
+  assert( pCur->iPage<0 || pCur->pPage->nOverflow==0 );
+
+end_insert:
+  return rc;
+}
+
+/*
+** This function is used as part of copying the current row from cursor
+** pSrc into cursor pDest. If the cursors are open on intkey tables, then
+** parameter iKey is used as the rowid value when the record is copied
+** into pDest. Otherwise, the record is copied verbatim.
+**
+** This function does not actually write the new value to cursor pDest.
+** Instead, it creates and populates any required overflow pages and
+** writes the data for the new cell into the BtShared.pTmpSpace buffer
+** for the destination database. The size of the cell, in bytes, is left
+** in BtShared.nPreformatSize. The caller completes the insertion by
+** calling sqlite3BtreeInsert() with the BTREE_PREFORMAT flag specified.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3BtreeTransferRow(BtCursor *pDest, BtCursor *pSrc, i64 iKey){
+  BtShared *pBt = pDest->pBt;
+  u8 *aOut = pBt->pTmpSpace;    /* Pointer to next output buffer */
+  const u8 *aIn;                /* Pointer to next input buffer */
+  u32 nIn;                      /* Size of input buffer aIn[] */
+  u32 nRem;                     /* Bytes of data still to copy */
+
+  getCellInfo(pSrc);
+  if( pSrc->info.nPayload<0x80 ){
+    *(aOut++) = pSrc->info.nPayload;
+  }else{
+    aOut += sqlite3PutVarint(aOut, pSrc->info.nPayload);
+  }
+  if( pDest->pKeyInfo==0 ) aOut += putVarint(aOut, iKey);
+  nIn = pSrc->info.nLocal;
+  aIn = pSrc->info.pPayload;
+  if( aIn+nIn>pSrc->pPage->aDataEnd ){
+    return SQLITE_CORRUPT_PAGE(pSrc->pPage);
+  }
+  nRem = pSrc->info.nPayload;
+  if( nIn==nRem && nIn<pDest->pPage->maxLocal ){
+    memcpy(aOut, aIn, nIn);
+    pBt->nPreformatSize = nIn + (aOut - pBt->pTmpSpace);
+    return SQLITE_OK;
+  }else{
+    int rc = SQLITE_OK;
+    Pager *pSrcPager = pSrc->pBt->pPager;
+    u8 *pPgnoOut = 0;
+    Pgno ovflIn = 0;
+    DbPage *pPageIn = 0;
+    MemPage *pPageOut = 0;
+    u32 nOut;                     /* Size of output buffer aOut[] */
+
+    nOut = btreePayloadToLocal(pDest->pPage, pSrc->info.nPayload);
+    pBt->nPreformatSize = nOut + (aOut - pBt->pTmpSpace);
+    if( nOut<pSrc->info.nPayload ){
+      pPgnoOut = &aOut[nOut];
+      pBt->nPreformatSize += 4;
+    }
+
+    if( nRem>nIn ){
+      if( aIn+nIn+4>pSrc->pPage->aDataEnd ){
+        return SQLITE_CORRUPT_PAGE(pSrc->pPage);
+      }
+      ovflIn = get4byte(&pSrc->info.pPayload[nIn]);
+    }
+
+    do {
+      nRem -= nOut;
+      do{
+        assert( nOut>0 );
+        if( nIn>0 ){
+          int nCopy = MIN(nOut, nIn);
+          memcpy(aOut, aIn, nCopy);
+          nOut -= nCopy;
+          nIn -= nCopy;
+          aOut += nCopy;
+          aIn += nCopy;
+        }
+        if( nOut>0 ){
+          sqlite3PagerUnref(pPageIn);
+          pPageIn = 0;
+          rc = sqlite3PagerGet(pSrcPager, ovflIn, &pPageIn, PAGER_GET_READONLY);
+          if( rc==SQLITE_OK ){
+            aIn = (const u8*)sqlite3PagerGetData(pPageIn);
+            ovflIn = get4byte(aIn);
+            aIn += 4;
+            nIn = pSrc->pBt->usableSize - 4;
+          }
+        }
+      }while( rc==SQLITE_OK && nOut>0 );
+
+      if( rc==SQLITE_OK && nRem>0 && ALWAYS(pPgnoOut) ){
+        Pgno pgnoNew;
+        MemPage *pNew = 0;
+        rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
+        put4byte(pPgnoOut, pgnoNew);
+        if( ISAUTOVACUUM(pBt) && pPageOut ){
+          ptrmapPut(pBt, pgnoNew, PTRMAP_OVERFLOW2, pPageOut->pgno, &rc);
+        }
+        releasePage(pPageOut);
+        pPageOut = pNew;
+        if( pPageOut ){
+          pPgnoOut = pPageOut->aData;
+          put4byte(pPgnoOut, 0);
+          aOut = &pPgnoOut[4];
+          nOut = MIN(pBt->usableSize - 4, nRem);
+        }
+      }
+    }while( nRem>0 && rc==SQLITE_OK );
+
+    releasePage(pPageOut);
+    sqlite3PagerUnref(pPageIn);
+    return rc;
+  }
+}
+
+/*
+** Delete the entry that the cursor is pointing to.
+**
+** If the BTREE_SAVEPOSITION bit of the flags parameter is zero, then
+** the cursor is left pointing at an arbitrary location after the delete.
+** But if that bit is set, then the cursor is left in a state such that
+** the next call to BtreeNext() or BtreePrev() moves it to the same row
+** as it would have been on if the call to BtreeDelete() had been omitted.
+**
+** The BTREE_AUXDELETE bit of flags indicates that is one of several deletes
+** associated with a single table entry and its indexes.  Only one of those
+** deletes is considered the "primary" delete.  The primary delete occurs
+** on a cursor that is not a BTREE_FORDELETE cursor.  All but one delete
+** operation on non-FORDELETE cursors is tagged with the AUXDELETE flag.
+** The BTREE_AUXDELETE bit is a hint that is not used by this implementation,
+** but which might be used by alternative storage engines.
+*/
+SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor *pCur, u8 flags){
+  Btree *p = pCur->pBtree;
+  BtShared *pBt = p->pBt;
+  int rc;                    /* Return code */
+  MemPage *pPage;            /* Page to delete cell from */
+  unsigned char *pCell;      /* Pointer to cell to delete */
+  int iCellIdx;              /* Index of cell to delete */
+  int iCellDepth;            /* Depth of node containing pCell */
+  CellInfo info;             /* Size of the cell being deleted */
+  u8 bPreserve;              /* Keep cursor valid.  2 for CURSOR_SKIPNEXT */
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pBt->inTransaction==TRANS_WRITE );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
+  assert( pCur->curFlags & BTCF_WriteFlag );
+  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
+  assert( !hasReadConflicts(p, pCur->pgnoRoot) );
+  assert( (flags & ~(BTREE_SAVEPOSITION | BTREE_AUXDELETE))==0 );
+  if( pCur->eState!=CURSOR_VALID ){
+    if( pCur->eState>=CURSOR_REQUIRESEEK ){
+      rc = btreeRestoreCursorPosition(pCur);
+      assert( rc!=SQLITE_OK || CORRUPT_DB || pCur->eState==CURSOR_VALID );
+      if( rc || pCur->eState!=CURSOR_VALID ) return rc;
+    }else{
+      return SQLITE_CORRUPT_PGNO(pCur->pgnoRoot);
+    }
+  }
+  assert( pCur->eState==CURSOR_VALID );
+
+  iCellDepth = pCur->iPage;
+  iCellIdx = pCur->ix;
+  pPage = pCur->pPage;
+  if( pPage->nCell<=iCellIdx ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  pCell = findCell(pPage, iCellIdx);
+  if( pPage->nFree<0 && btreeComputeFreeSpace(pPage) ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  if( pCell<&pPage->aCellIdx[pPage->nCell] ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+
+  /* If the BTREE_SAVEPOSITION bit is on, then the cursor position must
+  ** be preserved following this delete operation. If the current delete
+  ** will cause a b-tree rebalance, then this is done by saving the cursor
+  ** key and leaving the cursor in CURSOR_REQUIRESEEK state before
+  ** returning.
+  **
+  ** If the current delete will not cause a rebalance, then the cursor
+  ** will be left in CURSOR_SKIPNEXT state pointing to the entry immediately
+  ** before or after the deleted entry.
+  **
+  ** The bPreserve value records which path is required:
+  **
+  **    bPreserve==0         Not necessary to save the cursor position
+  **    bPreserve==1         Use CURSOR_REQUIRESEEK to save the cursor position
+  **    bPreserve==2         Cursor won't move.  Set CURSOR_SKIPNEXT.
+  */
+  bPreserve = (flags & BTREE_SAVEPOSITION)!=0;
+  if( bPreserve ){
+    if( !pPage->leaf
+     || (pPage->nFree+pPage->xCellSize(pPage,pCell)+2) >
+                                                   (int)(pBt->usableSize*2/3)
+     || pPage->nCell==1  /* See dbfuzz001.test for a test case */
+    ){
+      /* A b-tree rebalance will be required after deleting this entry.
+      ** Save the cursor key.  */
+      rc = saveCursorKey(pCur);
+      if( rc ) return rc;
+    }else{
+      bPreserve = 2;
+    }
+  }
+
+  /* If the page containing the entry to delete is not a leaf page, move
+  ** the cursor to the largest entry in the tree that is smaller than
+  ** the entry being deleted. This cell will replace the cell being deleted
+  ** from the internal node. The 'previous' entry is used for this instead
+  ** of the 'next' entry, as the previous entry is always a part of the
+  ** sub-tree headed by the child page of the cell being deleted. This makes
+  ** balancing the tree following the delete operation easier.  */
+  if( !pPage->leaf ){
+    rc = sqlite3BtreePrevious(pCur, 0);
+    assert( rc!=SQLITE_DONE );
+    if( rc ) return rc;
+  }
+
+  /* Save the positions of any other cursors open on this table before
+  ** making any modifications.  */
+  if( pCur->curFlags & BTCF_Multiple ){
+    rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
+    if( rc ) return rc;
+  }
+
+  /* If this is a delete operation to remove a row from a table b-tree,
+  ** invalidate any incrblob cursors open on the row being deleted.  */
+  if( pCur->pKeyInfo==0 && p->hasIncrblobCur ){
+    invalidateIncrblobCursors(p, pCur->pgnoRoot, pCur->info.nKey, 0);
+  }
+
+  /* Make the page containing the entry to be deleted writable. Then free any
+  ** overflow pages associated with the entry and finally remove the cell
+  ** itself from within the page.  */
+  rc = sqlite3PagerWrite(pPage->pDbPage);
+  if( rc ) return rc;
+  BTREE_CLEAR_CELL(rc, pPage, pCell, info);
+  dropCell(pPage, iCellIdx, info.nSize, &rc);
+  if( rc ) return rc;
+
+  /* If the cell deleted was not located on a leaf page, then the cursor
+  ** is currently pointing to the largest entry in the sub-tree headed
+  ** by the child-page of the cell that was just deleted from an internal
+  ** node. The cell from the leaf node needs to be moved to the internal
+  ** node to replace the deleted cell.  */
+  if( !pPage->leaf ){
+    MemPage *pLeaf = pCur->pPage;
+    int nCell;
+    Pgno n;
+    unsigned char *pTmp;
+
+    if( pLeaf->nFree<0 ){
+      rc = btreeComputeFreeSpace(pLeaf);
+      if( rc ) return rc;
+    }
+    if( iCellDepth<pCur->iPage-1 ){
+      n = pCur->apPage[iCellDepth+1]->pgno;
+    }else{
+      n = pCur->pPage->pgno;
+    }
+    pCell = findCell(pLeaf, pLeaf->nCell-1);
+    if( pCell<&pLeaf->aData[4] ) return SQLITE_CORRUPT_PAGE(pLeaf);
+    nCell = pLeaf->xCellSize(pLeaf, pCell);
+    assert( MX_CELL_SIZE(pBt) >= nCell );
+    pTmp = pBt->pTmpSpace;
+    assert( pTmp!=0 );
+    rc = sqlite3PagerWrite(pLeaf->pDbPage);
+    if( rc==SQLITE_OK ){
+      rc = insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n);
+    }
+    dropCell(pLeaf, pLeaf->nCell-1, nCell, &rc);
+    if( rc ) return rc;
+  }
+
+  /* Balance the tree. If the entry deleted was located on a leaf page,
+  ** then the cursor still points to that page. In this case the first
+  ** call to balance() repairs the tree, and the if(...) condition is
+  ** never true.
+  **
+  ** Otherwise, if the entry deleted was on an internal node page, then
+  ** pCur is pointing to the leaf page from which a cell was removed to
+  ** replace the cell deleted from the internal node. This is slightly
+  ** tricky as the leaf node may be underfull, and the internal node may
+  ** be either under or overfull. In this case run the balancing algorithm
+  ** on the leaf node first. If the balance proceeds far enough up the
+  ** tree that we can be sure that any problem in the internal node has
+  ** been corrected, so be it. Otherwise, after balancing the leaf node,
+  ** walk the cursor up the tree to the internal node and balance it as
+  ** well.  */
+  assert( pCur->pPage->nOverflow==0 );
+  assert( pCur->pPage->nFree>=0 );
+  if( pCur->pPage->nFree*3<=(int)pCur->pBt->usableSize*2 ){
+    /* Optimization: If the free space is less than 2/3rds of the page,
+    ** then balance() will always be a no-op.  No need to invoke it. */
+    rc = SQLITE_OK;
+  }else{
+    rc = balance(pCur);
+  }
+  if( rc==SQLITE_OK && pCur->iPage>iCellDepth ){
+    releasePageNotNull(pCur->pPage);
+    pCur->iPage--;
+    while( pCur->iPage>iCellDepth ){
+      releasePage(pCur->apPage[pCur->iPage--]);
+    }
+    pCur->pPage = pCur->apPage[pCur->iPage];
+    rc = balance(pCur);
+  }
+
+  if( rc==SQLITE_OK ){
+    if( bPreserve>1 ){
+      assert( (pCur->iPage==iCellDepth || CORRUPT_DB) );
+      assert( pPage==pCur->pPage || CORRUPT_DB );
+      assert( (pPage->nCell>0 || CORRUPT_DB) && iCellIdx<=pPage->nCell );
+      pCur->eState = CURSOR_SKIPNEXT;
+      if( iCellIdx>=pPage->nCell ){
+        pCur->skipNext = -1;
+        pCur->ix = pPage->nCell-1;
+      }else{
+        pCur->skipNext = 1;
+      }
+    }else{
+      rc = moveToRoot(pCur);
+      if( bPreserve ){
+        btreeReleaseAllCursorPages(pCur);
+        pCur->eState = CURSOR_REQUIRESEEK;
+      }
+      if( rc==SQLITE_EMPTY ) rc = SQLITE_OK;
+    }
+  }
+  return rc;
+}
+
+/*
+** Create a new BTree table.  Write into *piTable the page
+** number for the root page of the new table.
+**
+** The type of type is determined by the flags parameter.  Only the
+** following values of flags are currently in use.  Other values for
+** flags might not work:
+**
+**     BTREE_INTKEY|BTREE_LEAFDATA     Used for SQL tables with rowid keys
+**     BTREE_ZERODATA                  Used for SQL indices
+*/
+static int btreeCreateTable(Btree *p, Pgno *piTable, int createTabFlags){
+  BtShared *pBt = p->pBt;
+  MemPage *pRoot;
+  Pgno pgnoRoot;
+  int rc;
+  int ptfFlags;          /* Page-type flags for the root page of new table */
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( pBt->inTransaction==TRANS_WRITE );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
+
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
+  if( rc ){
+    return rc;
+  }
+#else
+  if( pBt->autoVacuum ){
+    Pgno pgnoMove;      /* Move a page here to make room for the root-page */
+    MemPage *pPageMove; /* The page to move to. */
+
+    /* Creating a new table may probably require moving an existing database
+    ** to make room for the new tables root page. In case this page turns
+    ** out to be an overflow page, delete all overflow page-map caches
+    ** held by open cursors.
+    */
+    invalidateAllOverflowCache(pBt);
+
+    /* Read the value of meta[3] from the database to determine where the
+    ** root page of the new table should go. meta[3] is the largest root-page
+    ** created so far, so the new root-page is (meta[3]+1).
+    */
+    sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &pgnoRoot);
+    if( pgnoRoot>btreePagecount(pBt) ){
+      return SQLITE_CORRUPT_PGNO(pgnoRoot);
+    }
+    pgnoRoot++;
+
+    /* The new root-page may not be allocated on a pointer-map page, or the
+    ** PENDING_BYTE page.
+    */
+    while( pgnoRoot==PTRMAP_PAGENO(pBt, pgnoRoot) ||
+        pgnoRoot==PENDING_BYTE_PAGE(pBt) ){
+      pgnoRoot++;
+    }
+    assert( pgnoRoot>=3 );
+
+    /* Allocate a page. The page that currently resides at pgnoRoot will
+    ** be moved to the allocated page (unless the allocated page happens
+    ** to reside at pgnoRoot).
+    */
+    rc = allocateBtreePage(pBt, &pPageMove, &pgnoMove, pgnoRoot, BTALLOC_EXACT);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    if( pgnoMove!=pgnoRoot ){
+      /* pgnoRoot is the page that will be used for the root-page of
+      ** the new table (assuming an error did not occur). But we were
+      ** allocated pgnoMove. If required (i.e. if it was not allocated
+      ** by extending the file), the current page at position pgnoMove
+      ** is already journaled.
+      */
+      u8 eType = 0;
+      Pgno iPtrPage = 0;
+
+      /* Save the positions of any open cursors. This is required in
+      ** case they are holding a reference to an xFetch reference
+      ** corresponding to page pgnoRoot.  */
+      rc = saveAllCursors(pBt, 0, 0);
+      releasePage(pPageMove);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+
+      /* Move the page currently at pgnoRoot to pgnoMove. */
+      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = ptrmapGet(pBt, pgnoRoot, &eType, &iPtrPage);
+      if( eType==PTRMAP_ROOTPAGE || eType==PTRMAP_FREEPAGE ){
+        rc = SQLITE_CORRUPT_PGNO(pgnoRoot);
+      }
+      if( rc!=SQLITE_OK ){
+        releasePage(pRoot);
+        return rc;
+      }
+      assert( eType!=PTRMAP_ROOTPAGE );
+      assert( eType!=PTRMAP_FREEPAGE );
+      rc = relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove, 0);
+      releasePage(pRoot);
+
+      /* Obtain the page at pgnoRoot */
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = sqlite3PagerWrite(pRoot->pDbPage);
+      if( rc!=SQLITE_OK ){
+        releasePage(pRoot);
+        return rc;
+      }
+    }else{
+      pRoot = pPageMove;
+    }
+
+    /* Update the pointer-map and meta-data with the new root-page number. */
+    ptrmapPut(pBt, pgnoRoot, PTRMAP_ROOTPAGE, 0, &rc);
+    if( rc ){
+      releasePage(pRoot);
+      return rc;
+    }
+
+    /* When the new root page was allocated, page 1 was made writable in
+    ** order either to increase the database filesize, or to decrement the
+    ** freelist count.  Hence, the sqlite3BtreeUpdateMeta() call cannot fail.
+    */
+    assert( sqlite3PagerIswriteable(pBt->pPage1->pDbPage) );
+    rc = sqlite3BtreeUpdateMeta(p, 4, pgnoRoot);
+    if( NEVER(rc) ){
+      releasePage(pRoot);
+      return rc;
+    }
+
+  }else{
+    rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
+    if( rc ) return rc;
+  }
+#endif
+  assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
+  if( createTabFlags & BTREE_INTKEY ){
+    ptfFlags = PTF_INTKEY | PTF_LEAFDATA | PTF_LEAF;
+  }else{
+    ptfFlags = PTF_ZERODATA | PTF_LEAF;
+  }
+  zeroPage(pRoot, ptfFlags);
+  sqlite3PagerUnref(pRoot->pDbPage);
+  assert( (pBt->openFlags & BTREE_SINGLE)==0 || pgnoRoot==2 );
+  *piTable = pgnoRoot;
+  return SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree *p, Pgno *piTable, int flags){
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = btreeCreateTable(p, piTable, flags);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Erase the given database page and all its children.  Return
+** the page to the freelist.
+*/
+static int clearDatabasePage(
+  BtShared *pBt,           /* The BTree that contains the table */
+  Pgno pgno,               /* Page number to clear */
+  int freePageFlag,        /* Deallocate page if true */
+  i64 *pnChange            /* Add number of Cells freed to this counter */
+){
+  MemPage *pPage;
+  int rc;
+  unsigned char *pCell;
+  int i;
+  int hdr;
+  CellInfo info;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pgno>btreePagecount(pBt) ){
+    return SQLITE_CORRUPT_PGNO(pgno);
+  }
+  rc = getAndInitPage(pBt, pgno, &pPage, 0);
+  if( rc ) return rc;
+  if( (pBt->openFlags & BTREE_SINGLE)==0
+   && sqlite3PagerPageRefcount(pPage->pDbPage) != (1 + (pgno==1))
+  ){
+    rc = SQLITE_CORRUPT_PAGE(pPage);
+    goto cleardatabasepage_out;
+  }
+  hdr = pPage->hdrOffset;
+  for(i=0; i<pPage->nCell; i++){
+    pCell = findCell(pPage, i);
+    if( !pPage->leaf ){
+      rc = clearDatabasePage(pBt, get4byte(pCell), 1, pnChange);
+      if( rc ) goto cleardatabasepage_out;
+    }
+    BTREE_CLEAR_CELL(rc, pPage, pCell, info);
+    if( rc ) goto cleardatabasepage_out;
+  }
+  if( !pPage->leaf ){
+    rc = clearDatabasePage(pBt, get4byte(&pPage->aData[hdr+8]), 1, pnChange);
+    if( rc ) goto cleardatabasepage_out;
+    if( pPage->intKey ) pnChange = 0;
+  }
+  if( pnChange ){
+    testcase( !pPage->intKey );
+    *pnChange += pPage->nCell;
+  }
+  if( freePageFlag ){
+    freePage(pPage, &rc);
+  }else if( (rc = sqlite3PagerWrite(pPage->pDbPage))==0 ){
+    zeroPage(pPage, pPage->aData[hdr] | PTF_LEAF);
+  }
+
+cleardatabasepage_out:
+  releasePage(pPage);
+  return rc;
+}
+
+/*
+** Delete all information from a single table in the database.  iTable is
+** the page number of the root of the table.  After this routine returns,
+** the root page is empty, but still exists.
+**
+** This routine will fail with SQLITE_LOCKED if there are any open
+** read cursors on the table.  Open write cursors are moved to the
+** root of the table.
+**
+** If pnChange is not NULL, then the integer value pointed to by pnChange
+** is incremented by the number of entries in the table.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree *p, int iTable, i64 *pnChange){
+  int rc;
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans==TRANS_WRITE );
+
+  rc = saveAllCursors(pBt, (Pgno)iTable, 0);
+
+  if( SQLITE_OK==rc ){
+    /* Invalidate all incrblob cursors open on table iTable (assuming iTable
+    ** is the root of a table b-tree - if it is not, the following call is
+    ** a no-op).  */
+    if( p->hasIncrblobCur ){
+      invalidateIncrblobCursors(p, (Pgno)iTable, 0, 1);
+    }
+    rc = clearDatabasePage(pBt, (Pgno)iTable, 0, pnChange);
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Delete all information from the single table that pCur is open on.
+**
+** This routine only work for pCur on an ephemeral table.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClearTableOfCursor(BtCursor *pCur){
+  return sqlite3BtreeClearTable(pCur->pBtree, pCur->pgnoRoot, 0);
+}
+
+/*
+** Erase all information in a table and add the root of the table to
+** the freelist.  Except, the root of the principle table (the one on
+** page 1) is never added to the freelist.
+**
+** This routine will fail with SQLITE_LOCKED if there are any open
+** cursors on the table.
+**
+** If AUTOVACUUM is enabled and the page at iTable is not the last
+** root page in the database file, then the last root page
+** in the database file is moved into the slot formerly occupied by
+** iTable and that last slot formerly occupied by the last root page
+** is added to the freelist instead of iTable.  In this say, all
+** root pages are kept at the beginning of the database file, which
+** is necessary for AUTOVACUUM to work right.  *piMoved is set to the
+** page number that used to be the last root page in the file before
+** the move.  If no page gets moved, *piMoved is set to 0.
+** The last root page is recorded in meta[3] and the value of
+** meta[3] is updated by this procedure.
+*/
+static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
+  int rc;
+  MemPage *pPage = 0;
+  BtShared *pBt = p->pBt;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( p->inTrans==TRANS_WRITE );
+  assert( iTable>=2 );
+  if( iTable>btreePagecount(pBt) ){
+    return SQLITE_CORRUPT_PGNO(iTable);
+  }
+
+  rc = sqlite3BtreeClearTable(p, iTable, 0);
+  if( rc ) return rc;
+  rc = btreeGetPage(pBt, (Pgno)iTable, &pPage, 0);
+  if( NEVER(rc) ){
+    releasePage(pPage);
+    return rc;
+  }
+
+  *piMoved = 0;
+
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  freePage(pPage, &rc);
+  releasePage(pPage);
+#else
+  if( pBt->autoVacuum ){
+    Pgno maxRootPgno;
+    sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &maxRootPgno);
+
+    if( iTable==maxRootPgno ){
+      /* If the table being dropped is the table with the largest root-page
+      ** number in the database, put the root page on the free list.
+      */
+      freePage(pPage, &rc);
+      releasePage(pPage);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }else{
+      /* The table being dropped does not have the largest root-page
+      ** number in the database. So move the page that does into the
+      ** gap left by the deleted root-page.
+      */
+      MemPage *pMove;
+      releasePage(pPage);
+      rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = relocatePage(pBt, pMove, PTRMAP_ROOTPAGE, 0, iTable, 0);
+      releasePage(pMove);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      pMove = 0;
+      rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
+      freePage(pMove, &rc);
+      releasePage(pMove);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      *piMoved = maxRootPgno;
+    }
+
+    /* Set the new 'max-root-page' value in the database header. This
+    ** is the old value less one, less one more if that happens to
+    ** be a root-page number, less one again if that is the
+    ** PENDING_BYTE_PAGE.
+    */
+    maxRootPgno--;
+    while( maxRootPgno==PENDING_BYTE_PAGE(pBt)
+           || PTRMAP_ISPAGE(pBt, maxRootPgno) ){
+      maxRootPgno--;
+    }
+    assert( maxRootPgno!=PENDING_BYTE_PAGE(pBt) );
+
+    rc = sqlite3BtreeUpdateMeta(p, 4, maxRootPgno);
+  }else{
+    freePage(pPage, &rc);
+    releasePage(pPage);
+  }
+#endif
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree *p, int iTable, int *piMoved){
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = btreeDropTable(p, iTable, piMoved);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+
+/*
+** This function may only be called if the b-tree connection already
+** has a read or write transaction open on the database.
+**
+** Read the meta-information out of a database file.  Meta[0]
+** is the number of free pages currently in the database.  Meta[1]
+** through meta[15] are available for use by higher layers.  Meta[0]
+** is read-only, the others are read/write.
+**
+** The schema layer numbers meta values differently.  At the schema
+** layer (and the SetCookie and ReadCookie opcodes) the number of
+** free pages is not visible.  So Cookie[0] is the same as Meta[1].
+**
+** This routine treats Meta[BTREE_DATA_VERSION] as a special case.  Instead
+** of reading the value out of the header, it instead loads the "DataVersion"
+** from the pager.  The BTREE_DATA_VERSION value is not actually stored in the
+** database file.  It is a number computed by the pager.  But its access
+** pattern is the same as header meta values, and so it is convenient to
+** read it from this routine.
+*/
+SQLITE_PRIVATE void sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
+  BtShared *pBt = p->pBt;
+
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans>TRANS_NONE );
+  assert( SQLITE_OK==querySharedCacheTableLock(p, SCHEMA_ROOT, READ_LOCK) );
+  assert( pBt->pPage1 );
+  assert( idx>=0 && idx<=15 );
+
+  if( idx==BTREE_DATA_VERSION ){
+    *pMeta = sqlite3PagerDataVersion(pBt->pPager) + p->iBDataVersion;
+  }else{
+    *pMeta = get4byte(&pBt->pPage1->aData[36 + idx*4]);
+  }
+
+  /* If auto-vacuum is disabled in this build and this is an auto-vacuum
+  ** database, mark the database as read-only.  */
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ){
+    pBt->btsFlags |= BTS_READ_ONLY;
+  }
+#endif
+
+  sqlite3BtreeLeave(p);
+}
+
+/*
+** Write meta-information back into the database.  Meta[0] is
+** read-only and may not be written.
+*/
+SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree *p, int idx, u32 iMeta){
+  BtShared *pBt = p->pBt;
+  unsigned char *pP1;
+  int rc;
+  assert( idx>=1 && idx<=15 );
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans==TRANS_WRITE );
+  assert( pBt->pPage1!=0 );
+  pP1 = pBt->pPage1->aData;
+  rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+  if( rc==SQLITE_OK ){
+    put4byte(&pP1[36 + idx*4], iMeta);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( idx==BTREE_INCR_VACUUM ){
+      assert( pBt->autoVacuum || iMeta==0 );
+      assert( iMeta==0 || iMeta==1 );
+      pBt->incrVacuum = (u8)iMeta;
+    }
+#endif
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** The first argument, pCur, is a cursor opened on some b-tree. Count the
+** number of entries in the b-tree and write the result to *pnEntry.
+**
+** SQLITE_OK is returned if the operation is successfully executed.
+** Otherwise, if an error is encountered (i.e. an IO error or database
+** corruption) an SQLite error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCount(sqlite3 *db, BtCursor *pCur, i64 *pnEntry){
+  i64 nEntry = 0;                      /* Value to return in *pnEntry */
+  int rc;                              /* Return code */
+
+  rc = moveToRoot(pCur);
+  if( rc==SQLITE_EMPTY ){
+    *pnEntry = 0;
+    return SQLITE_OK;
+  }
+
+  /* Unless an error occurs, the following loop runs one iteration for each
+  ** page in the B-Tree structure (not including overflow pages).
+  */
+  while( rc==SQLITE_OK && !AtomicLoad(&db->u1.isInterrupted) ){
+    int iIdx;                          /* Index of child node in parent */
+    MemPage *pPage;                    /* Current page of the b-tree */
+
+    /* If this is a leaf page or the tree is not an int-key tree, then
+    ** this page contains countable entries. Increment the entry counter
+    ** accordingly.
+    */
+    pPage = pCur->pPage;
+    if( pPage->leaf || !pPage->intKey ){
+      nEntry += pPage->nCell;
+    }
+
+    /* pPage is a leaf node. This loop navigates the cursor so that it
+    ** points to the first interior cell that it points to the parent of
+    ** the next page in the tree that has not yet been visited. The
+    ** pCur->aiIdx[pCur->iPage] value is set to the index of the parent cell
+    ** of the page, or to the number of cells in the page if the next page
+    ** to visit is the right-child of its parent.
+    **
+    ** If all pages in the tree have been visited, return SQLITE_OK to the
+    ** caller.
+    */
+    if( pPage->leaf ){
+      do {
+        if( pCur->iPage==0 ){
+          /* All pages of the b-tree have been visited. Return successfully. */
+          *pnEntry = nEntry;
+          return moveToRoot(pCur);
+        }
+        moveToParent(pCur);
+      }while ( pCur->ix>=pCur->pPage->nCell );
+
+      pCur->ix++;
+      pPage = pCur->pPage;
+    }
+
+    /* Descend to the child node of the cell that the cursor currently
+    ** points at. This is the right-child if (iIdx==pPage->nCell).
+    */
+    iIdx = pCur->ix;
+    if( iIdx==pPage->nCell ){
+      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
+    }else{
+      rc = moveToChild(pCur, get4byte(findCell(pPage, iIdx)));
+    }
+  }
+
+  /* An error has occurred. Return an error code. */
+  return rc;
+}
+
+/*
+** Return the pager associated with a BTree.  This routine is used for
+** testing and debugging only.
+*/
+SQLITE_PRIVATE Pager *sqlite3BtreePager(Btree *p){
+  return p->pBt->pPager;
+}
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** Record an OOM error during integrity_check
+*/
+static void checkOom(IntegrityCk *pCheck){
+  pCheck->rc = SQLITE_NOMEM;
+  pCheck->mxErr = 0;  /* Causes integrity_check processing to stop */
+  if( pCheck->nErr==0 ) pCheck->nErr++;
+}
+
+/*
+** Invoke the progress handler, if appropriate.  Also check for an
+** interrupt.
+*/
+static void checkProgress(IntegrityCk *pCheck){
+  sqlite3 *db = pCheck->db;
+  if( AtomicLoad(&db->u1.isInterrupted) ){
+    pCheck->rc = SQLITE_INTERRUPT;
+    pCheck->nErr++;
+    pCheck->mxErr = 0;
+  }
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  if( db->xProgress ){
+    assert( db->nProgressOps>0 );
+    pCheck->nStep++;
+    if( (pCheck->nStep % db->nProgressOps)==0
+     && db->xProgress(db->pProgressArg)
+    ){
+      pCheck->rc = SQLITE_INTERRUPT;
+      pCheck->nErr++;
+      pCheck->mxErr = 0;
+    }
+  }
+#endif
+}
+
+/*
+** Append a message to the error message string.
+*/
+static void checkAppendMsg(
+  IntegrityCk *pCheck,
+  const char *zFormat,
+  ...
+){
+  va_list ap;
+  checkProgress(pCheck);
+  if( !pCheck->mxErr ) return;
+  pCheck->mxErr--;
+  pCheck->nErr++;
+  va_start(ap, zFormat);
+  if( pCheck->errMsg.nChar ){
+    sqlite3_str_append(&pCheck->errMsg, "\n", 1);
+  }
+  if( pCheck->zPfx ){
+    sqlite3_str_appendf(&pCheck->errMsg, pCheck->zPfx,
+                        pCheck->v0, pCheck->v1, pCheck->v2);
+  }
+  sqlite3_str_vappendf(&pCheck->errMsg, zFormat, ap);
+  va_end(ap);
+  if( pCheck->errMsg.accError==SQLITE_NOMEM ){
+    checkOom(pCheck);
+  }
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+
+/*
+** Return non-zero if the bit in the IntegrityCk.aPgRef[] array that
+** corresponds to page iPg is already set.
+*/
+static int getPageReferenced(IntegrityCk *pCheck, Pgno iPg){
+  assert( pCheck->aPgRef!=0 );
+  assert( iPg<=pCheck->nCkPage && sizeof(pCheck->aPgRef[0])==1 );
+  return (pCheck->aPgRef[iPg/8] & (1 << (iPg & 0x07)));
+}
+
+/*
+** Set the bit in the IntegrityCk.aPgRef[] array that corresponds to page iPg.
+*/
+static void setPageReferenced(IntegrityCk *pCheck, Pgno iPg){
+  assert( pCheck->aPgRef!=0 );
+  assert( iPg<=pCheck->nCkPage && sizeof(pCheck->aPgRef[0])==1 );
+  pCheck->aPgRef[iPg/8] |= (1 << (iPg & 0x07));
+}
+
+
+/*
+** Add 1 to the reference count for page iPage.  If this is the second
+** reference to the page, add an error message to pCheck->zErrMsg.
+** Return 1 if there are 2 or more references to the page and 0 if
+** if this is the first reference to the page.
+**
+** Also check that the page number is in bounds.
+*/
+static int checkRef(IntegrityCk *pCheck, Pgno iPage){
+  if( iPage>pCheck->nCkPage || iPage==0 ){
+    checkAppendMsg(pCheck, "invalid page number %u", iPage);
+    return 1;
+  }
+  if( getPageReferenced(pCheck, iPage) ){
+    checkAppendMsg(pCheck, "2nd reference to page %u", iPage);
+    return 1;
+  }
+  setPageReferenced(pCheck, iPage);
+  return 0;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Check that the entry in the pointer-map for page iChild maps to
+** page iParent, pointer type ptrType. If not, append an error message
+** to pCheck.
+*/
+static void checkPtrmap(
+  IntegrityCk *pCheck,   /* Integrity check context */
+  Pgno iChild,           /* Child page number */
+  u8 eType,              /* Expected pointer map type */
+  Pgno iParent           /* Expected pointer map parent page number */
+){
+  int rc;
+  u8 ePtrmapType;
+  Pgno iPtrmapParent;
+
+  rc = ptrmapGet(pCheck->pBt, iChild, &ePtrmapType, &iPtrmapParent);
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ) checkOom(pCheck);
+    checkAppendMsg(pCheck, "Failed to read ptrmap key=%u", iChild);
+    return;
+  }
+
+  if( ePtrmapType!=eType || iPtrmapParent!=iParent ){
+    checkAppendMsg(pCheck,
+      "Bad ptr map entry key=%u expected=(%u,%u) got=(%u,%u)",
+      iChild, eType, iParent, ePtrmapType, iPtrmapParent);
+  }
+}
+#endif
+
+/*
+** Check the integrity of the freelist or of an overflow page list.
+** Verify that the number of pages on the list is N.
+*/
+static void checkList(
+  IntegrityCk *pCheck,  /* Integrity checking context */
+  int isFreeList,       /* True for a freelist.  False for overflow page list */
+  Pgno iPage,           /* Page number for first page in the list */
+  u32 N                 /* Expected number of pages in the list */
+){
+  int i;
+  u32 expected = N;
+  int nErrAtStart = pCheck->nErr;
+  while( iPage!=0 && pCheck->mxErr ){
+    DbPage *pOvflPage;
+    unsigned char *pOvflData;
+    if( checkRef(pCheck, iPage) ) break;
+    N--;
+    if( sqlite3PagerGet(pCheck->pPager, (Pgno)iPage, &pOvflPage, 0) ){
+      checkAppendMsg(pCheck, "failed to get page %u", iPage);
+      break;
+    }
+    pOvflData = (unsigned char *)sqlite3PagerGetData(pOvflPage);
+    if( isFreeList ){
+      u32 n = (u32)get4byte(&pOvflData[4]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pCheck->pBt->autoVacuum ){
+        checkPtrmap(pCheck, iPage, PTRMAP_FREEPAGE, 0);
+      }
+#endif
+      if( n>pCheck->pBt->usableSize/4-2 ){
+        checkAppendMsg(pCheck,
+           "freelist leaf count too big on page %u", iPage);
+        N--;
+      }else{
+        for(i=0; i<(int)n; i++){
+          Pgno iFreePage = get4byte(&pOvflData[8+i*4]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+          if( pCheck->pBt->autoVacuum ){
+            checkPtrmap(pCheck, iFreePage, PTRMAP_FREEPAGE, 0);
+          }
+#endif
+          checkRef(pCheck, iFreePage);
+        }
+        N -= n;
+      }
+    }
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    else{
+      /* If this database supports auto-vacuum and iPage is not the last
+      ** page in this overflow list, check that the pointer-map entry for
+      ** the following page matches iPage.
+      */
+      if( pCheck->pBt->autoVacuum && N>0 ){
+        i = get4byte(pOvflData);
+        checkPtrmap(pCheck, i, PTRMAP_OVERFLOW2, iPage);
+      }
+    }
+#endif
+    iPage = get4byte(pOvflData);
+    sqlite3PagerUnref(pOvflPage);
+  }
+  if( N && nErrAtStart==pCheck->nErr ){
+    checkAppendMsg(pCheck,
+      "%s is %u but should be %u",
+      isFreeList ? "size" : "overflow list length",
+      expected-N, expected);
+  }
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+/*
+** An implementation of a min-heap.
+**
+** aHeap[0] is the number of elements on the heap.  aHeap[1] is the
+** root element.  The daughter nodes of aHeap[N] are aHeap[N*2]
+** and aHeap[N*2+1].
+**
+** The heap property is this:  Every node is less than or equal to both
+** of its daughter nodes.  A consequence of the heap property is that the
+** root node aHeap[1] is always the minimum value currently in the heap.
+**
+** The btreeHeapInsert() routine inserts an unsigned 32-bit number onto
+** the heap, preserving the heap property.  The btreeHeapPull() routine
+** removes the root element from the heap (the minimum value in the heap)
+** and then moves other nodes around as necessary to preserve the heap
+** property.
+**
+** This heap is used for cell overlap and coverage testing.  Each u32
+** entry represents the span of a cell or freeblock on a btree page.
+** The upper 16 bits are the index of the first byte of a range and the
+** lower 16 bits are the index of the last byte of that range.
+*/
+static void btreeHeapInsert(u32 *aHeap, u32 x){
+  u32 j, i;
+  assert( aHeap!=0 );
+  i = ++aHeap[0];
+  aHeap[i] = x;
+  while( (j = i/2)>0 && aHeap[j]>aHeap[i] ){
+    x = aHeap[j];
+    aHeap[j] = aHeap[i];
+    aHeap[i] = x;
+    i = j;
+  }
+}
+static int btreeHeapPull(u32 *aHeap, u32 *pOut){
+  u32 j, i, x;
+  if( (x = aHeap[0])==0 ) return 0;
+  *pOut = aHeap[1];
+  aHeap[1] = aHeap[x];
+  aHeap[x] = 0xffffffff;
+  aHeap[0]--;
+  i = 1;
+  while( (j = i*2)<=aHeap[0] ){
+    if( aHeap[j]>aHeap[j+1] ) j++;
+    if( aHeap[i]<aHeap[j] ) break;
+    x = aHeap[i];
+    aHeap[i] = aHeap[j];
+    aHeap[j] = x;
+    i = j;
+  }
+  return 1;
+}
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** Do various sanity checks on a single page of a tree.  Return
+** the tree depth.  Root pages return 0.  Parents of root pages
+** return 1, and so forth.
+**
+** These checks are done:
+**
+**      1.  Make sure that cells and freeblocks do not overlap
+**          but combine to completely cover the page.
+**      2.  Make sure integer cell keys are in order.
+**      3.  Check the integrity of overflow pages.
+**      4.  Recursively call checkTreePage on all children.
+**      5.  Verify that the depth of all children is the same.
+*/
+static int checkTreePage(
+  IntegrityCk *pCheck,  /* Context for the sanity check */
+  Pgno iPage,           /* Page number of the page to check */
+  i64 *piMinKey,        /* Write minimum integer primary key here */
+  i64 maxKey            /* Error if integer primary key greater than this */
+){
+  MemPage *pPage = 0;      /* The page being analyzed */
+  int i;                   /* Loop counter */
+  int rc;                  /* Result code from subroutine call */
+  int depth = -1, d2;      /* Depth of a subtree */
+  int pgno;                /* Page number */
+  int nFrag;               /* Number of fragmented bytes on the page */
+  int hdr;                 /* Offset to the page header */
+  int cellStart;           /* Offset to the start of the cell pointer array */
+  int nCell;               /* Number of cells */
+  int doCoverageCheck = 1; /* True if cell coverage checking should be done */
+  int keyCanBeEqual = 1;   /* True if IPK can be equal to maxKey
+                           ** False if IPK must be strictly less than maxKey */
+  u8 *data;                /* Page content */
+  u8 *pCell;               /* Cell content */
+  u8 *pCellIdx;            /* Next element of the cell pointer array */
+  BtShared *pBt;           /* The BtShared object that owns pPage */
+  u32 pc;                  /* Address of a cell */
+  u32 usableSize;          /* Usable size of the page */
+  u32 contentOffset;       /* Offset to the start of the cell content area */
+  u32 *heap = 0;           /* Min-heap used for checking cell coverage */
+  u32 x, prev = 0;         /* Next and previous entry on the min-heap */
+  const char *saved_zPfx = pCheck->zPfx;
+  int saved_v1 = pCheck->v1;
+  int saved_v2 = pCheck->v2;
+  u8 savedIsInit = 0;
+
+  /* Check that the page exists
+  */
+  checkProgress(pCheck);
+  if( pCheck->mxErr==0 ) goto end_of_check;
+  pBt = pCheck->pBt;
+  usableSize = pBt->usableSize;
+  if( iPage==0 ) return 0;
+  if( checkRef(pCheck, iPage) ) return 0;
+  pCheck->zPfx = "Tree %u page %u: ";
+  pCheck->v1 = iPage;
+  if( (rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0 ){
+    checkAppendMsg(pCheck,
+       "unable to get the page. error code=%d", rc);
+    if( rc==SQLITE_IOERR_NOMEM ) pCheck->rc = SQLITE_NOMEM;
+    goto end_of_check;
+  }
+
+  /* Clear MemPage.isInit to make sure the corruption detection code in
+  ** btreeInitPage() is executed.  */
+  savedIsInit = pPage->isInit;
+  pPage->isInit = 0;
+  if( (rc = btreeInitPage(pPage))!=0 ){
+    assert( rc==SQLITE_CORRUPT );  /* The only possible error from InitPage */
+    checkAppendMsg(pCheck,
+                   "btreeInitPage() returns error code %d", rc);
+    goto end_of_check;
+  }
+  if( (rc = btreeComputeFreeSpace(pPage))!=0 ){
+    assert( rc==SQLITE_CORRUPT );
+    checkAppendMsg(pCheck, "free space corruption", rc);
+    goto end_of_check;
+  }
+  data = pPage->aData;
+  hdr = pPage->hdrOffset;
+
+  /* Set up for cell analysis */
+  pCheck->zPfx = "Tree %u page %u cell %u: ";
+  contentOffset = get2byteNotZero(&data[hdr+5]);
+  assert( contentOffset<=usableSize );  /* Enforced by btreeInitPage() */
+
+  /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the
+  ** number of cells on the page. */
+  nCell = get2byte(&data[hdr+3]);
+  assert( pPage->nCell==nCell );
+  if( pPage->leaf || pPage->intKey==0 ){
+    pCheck->nRow += nCell;
+  }
+
+  /* EVIDENCE-OF: R-23882-45353 The cell pointer array of a b-tree page
+  ** immediately follows the b-tree page header. */
+  cellStart = hdr + 12 - 4*pPage->leaf;
+  assert( pPage->aCellIdx==&data[cellStart] );
+  pCellIdx = &data[cellStart + 2*(nCell-1)];
+
+  if( !pPage->leaf ){
+    /* Analyze the right-child page of internal pages */
+    pgno = get4byte(&data[hdr+8]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum ){
+      pCheck->zPfx = "Tree %u page %u right child: ";
+      checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage);
+    }
+#endif
+    depth = checkTreePage(pCheck, pgno, &maxKey, maxKey);
+    keyCanBeEqual = 0;
+  }else{
+    /* For leaf pages, the coverage check will occur in the same loop
+    ** as the other cell checks, so initialize the heap.  */
+    heap = pCheck->heap;
+    heap[0] = 0;
+  }
+
+  /* EVIDENCE-OF: R-02776-14802 The cell pointer array consists of K 2-byte
+  ** integer offsets to the cell contents. */
+  for(i=nCell-1; i>=0 && pCheck->mxErr; i--){
+    CellInfo info;
+
+    /* Check cell size */
+    pCheck->v2 = i;
+    assert( pCellIdx==&data[cellStart + i*2] );
+    pc = get2byteAligned(pCellIdx);
+    pCellIdx -= 2;
+    if( pc<contentOffset || pc>usableSize-4 ){
+      checkAppendMsg(pCheck, "Offset %u out of range %u..%u",
+                             pc, contentOffset, usableSize-4);
+      doCoverageCheck = 0;
+      continue;
+    }
+    pCell = &data[pc];
+    pPage->xParseCell(pPage, pCell, &info);
+    if( pc+info.nSize>usableSize ){
+      checkAppendMsg(pCheck, "Extends off end of page");
+      doCoverageCheck = 0;
+      continue;
+    }
+
+    /* Check for integer primary key out of range */
+    if( pPage->intKey ){
+      if( keyCanBeEqual ? (info.nKey > maxKey) : (info.nKey >= maxKey) ){
+        checkAppendMsg(pCheck, "Rowid %lld out of order", info.nKey);
+      }
+      maxKey = info.nKey;
+      keyCanBeEqual = 0;     /* Only the first key on the page may ==maxKey */
+    }
+
+    /* Check the content overflow list */
+    if( info.nPayload>info.nLocal ){
+      u32 nPage;       /* Number of pages on the overflow chain */
+      Pgno pgnoOvfl;   /* First page of the overflow chain */
+      assert( pc + info.nSize - 4 <= usableSize );
+      nPage = (info.nPayload - info.nLocal + usableSize - 5)/(usableSize - 4);
+      pgnoOvfl = get4byte(&pCell[info.nSize - 4]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pBt->autoVacuum ){
+        checkPtrmap(pCheck, pgnoOvfl, PTRMAP_OVERFLOW1, iPage);
+      }
+#endif
+      checkList(pCheck, 0, pgnoOvfl, nPage);
+    }
+
+    if( !pPage->leaf ){
+      /* Check sanity of left child page for internal pages */
+      pgno = get4byte(pCell);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pBt->autoVacuum ){
+        checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage);
+      }
+#endif
+      d2 = checkTreePage(pCheck, pgno, &maxKey, maxKey);
+      keyCanBeEqual = 0;
+      if( d2!=depth ){
+        checkAppendMsg(pCheck, "Child page depth differs");
+        depth = d2;
+      }
+    }else{
+      /* Populate the coverage-checking heap for leaf pages */
+      btreeHeapInsert(heap, (pc<<16)|(pc+info.nSize-1));
+    }
+  }
+  *piMinKey = maxKey;
+
+  /* Check for complete coverage of the page
+  */
+  pCheck->zPfx = 0;
+  if( doCoverageCheck && pCheck->mxErr>0 ){
+    /* For leaf pages, the min-heap has already been initialized and the
+    ** cells have already been inserted.  But for internal pages, that has
+    ** not yet been done, so do it now */
+    if( !pPage->leaf ){
+      heap = pCheck->heap;
+      heap[0] = 0;
+      for(i=nCell-1; i>=0; i--){
+        u32 size;
+        pc = get2byteAligned(&data[cellStart+i*2]);
+        size = pPage->xCellSize(pPage, &data[pc]);
+        btreeHeapInsert(heap, (pc<<16)|(pc+size-1));
+      }
+    }
+    assert( heap!=0 );
+    /* Add the freeblocks to the min-heap
+    **
+    ** EVIDENCE-OF: R-20690-50594 The second field of the b-tree page header
+    ** is the offset of the first freeblock, or zero if there are no
+    ** freeblocks on the page.
+    */
+    i = get2byte(&data[hdr+1]);
+    while( i>0 ){
+      int size, j;
+      assert( (u32)i<=usableSize-4 ); /* Enforced by btreeComputeFreeSpace() */
+      size = get2byte(&data[i+2]);
+      assert( (u32)(i+size)<=usableSize ); /* due to btreeComputeFreeSpace() */
+      btreeHeapInsert(heap, (((u32)i)<<16)|(i+size-1));
+      /* EVIDENCE-OF: R-58208-19414 The first 2 bytes of a freeblock are a
+      ** big-endian integer which is the offset in the b-tree page of the next
+      ** freeblock in the chain, or zero if the freeblock is the last on the
+      ** chain. */
+      j = get2byte(&data[i]);
+      /* EVIDENCE-OF: R-06866-39125 Freeblocks are always connected in order of
+      ** increasing offset. */
+      assert( j==0 || j>i+size );     /* Enforced by btreeComputeFreeSpace() */
+      assert( (u32)j<=usableSize-4 ); /* Enforced by btreeComputeFreeSpace() */
+      i = j;
+    }
+    /* Analyze the min-heap looking for overlap between cells and/or
+    ** freeblocks, and counting the number of untracked bytes in nFrag.
+    **
+    ** Each min-heap entry is of the form:    (start_address<<16)|end_address.
+    ** There is an implied first entry the covers the page header, the cell
+    ** pointer index, and the gap between the cell pointer index and the start
+    ** of cell content.
+    **
+    ** The loop below pulls entries from the min-heap in order and compares
+    ** the start_address against the previous end_address.  If there is an
+    ** overlap, that means bytes are used multiple times.  If there is a gap,
+    ** that gap is added to the fragmentation count.
+    */
+    nFrag = 0;
+    prev = contentOffset - 1;   /* Implied first min-heap entry */
+    while( btreeHeapPull(heap,&x) ){
+      if( (prev&0xffff)>=(x>>16) ){
+        checkAppendMsg(pCheck,
+          "Multiple uses for byte %u of page %u", x>>16, iPage);
+        break;
+      }else{
+        nFrag += (x>>16) - (prev&0xffff) - 1;
+        prev = x;
+      }
+    }
+    nFrag += usableSize - (prev&0xffff) - 1;
+    /* EVIDENCE-OF: R-43263-13491 The total number of bytes in all fragments
+    ** is stored in the fifth field of the b-tree page header.
+    ** EVIDENCE-OF: R-07161-27322 The one-byte integer at offset 7 gives the
+    ** number of fragmented free bytes within the cell content area.
+    */
+    if( heap[0]==0 && nFrag!=data[hdr+7] ){
+      checkAppendMsg(pCheck,
+          "Fragmentation of %u bytes reported as %u on page %u",
+          nFrag, data[hdr+7], iPage);
+    }
+  }
+
+end_of_check:
+  if( !doCoverageCheck ) pPage->isInit = savedIsInit;
+  releasePage(pPage);
+  pCheck->zPfx = saved_zPfx;
+  pCheck->v1 = saved_v1;
+  pCheck->v2 = saved_v2;
+  return depth+1;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** This routine does a complete check of the given BTree file.  aRoot[] is
+** an array of pages numbers were each page number is the root page of
+** a table.  nRoot is the number of entries in aRoot.
+**
+** A read-only or read-write transaction must be opened before calling
+** this function.
+**
+** Write the number of error seen in *pnErr.  Except for some memory
+** allocation errors,  an error message held in memory obtained from
+** malloc is returned if *pnErr is non-zero.  If *pnErr==0 then NULL is
+** returned.  If a memory allocation error occurs, NULL is returned.
+**
+** If the first entry in aRoot[] is 0, that indicates that the list of
+** root pages is incomplete.  This is a "partial integrity-check".  This
+** happens when performing an integrity check on a single table.  The
+** zero is skipped, of course.  But in addition, the freelist checks
+** and the checks to make sure every page is referenced are also skipped,
+** since obviously it is not possible to know which pages are covered by
+** the unverified btrees.  Except, if aRoot[1] is 1, then the freelist
+** checks are still performed.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIntegrityCheck(
+  sqlite3 *db,  /* Database connection that is running the check */
+  Btree *p,     /* The btree to be checked */
+  Pgno *aRoot,  /* An array of root pages numbers for individual trees */
+  Mem *aCnt,    /* Memory cells to write counts for each tree to */
+  int nRoot,    /* Number of entries in aRoot[] */
+  int mxErr,    /* Stop reporting errors after this many */
+  int *pnErr,   /* OUT: Write number of errors seen to this variable */
+  char **pzOut  /* OUT: Write the error message string here */
+){
+  Pgno i;
+  IntegrityCk sCheck;
+  BtShared *pBt = p->pBt;
+  u64 savedDbFlags = pBt->db->flags;
+  char zErr[100];
+  int bPartial = 0;            /* True if not checking all btrees */
+  int bCkFreelist = 1;         /* True to scan the freelist */
+  VVA_ONLY( int nRef );
+
+  assert( nRoot>0 );
+  assert( aCnt!=0 );
+
+  /* aRoot[0]==0 means this is a partial check */
+  if( aRoot[0]==0 ){
+    assert( nRoot>1 );
+    bPartial = 1;
+    if( aRoot[1]!=1 ) bCkFreelist = 0;
+  }
+
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans>TRANS_NONE && pBt->inTransaction>TRANS_NONE );
+  VVA_ONLY( nRef = sqlite3PagerRefcount(pBt->pPager) );
+  assert( nRef>=0 );
+  memset(&sCheck, 0, sizeof(sCheck));
+  sCheck.db = db;
+  sCheck.pBt = pBt;
+  sCheck.pPager = pBt->pPager;
+  sCheck.nCkPage = btreePagecount(sCheck.pBt);
+  sCheck.mxErr = mxErr;
+  sqlite3StrAccumInit(&sCheck.errMsg, 0, zErr, sizeof(zErr), SQLITE_MAX_LENGTH);
+  sCheck.errMsg.printfFlags = SQLITE_PRINTF_INTERNAL;
+  if( sCheck.nCkPage==0 ){
+    goto integrity_ck_cleanup;
+  }
+
+  sCheck.aPgRef = sqlite3MallocZero((sCheck.nCkPage / 8)+ 1);
+  if( !sCheck.aPgRef ){
+    checkOom(&sCheck);
+    goto integrity_ck_cleanup;
+  }
+  sCheck.heap = (u32*)sqlite3PageMalloc( pBt->pageSize );
+  if( sCheck.heap==0 ){
+    checkOom(&sCheck);
+    goto integrity_ck_cleanup;
+  }
+
+  i = PENDING_BYTE_PAGE(pBt);
+  if( i<=sCheck.nCkPage ) setPageReferenced(&sCheck, i);
+
+  /* Check the integrity of the freelist
+  */
+  if( bCkFreelist ){
+    sCheck.zPfx = "Freelist: ";
+    checkList(&sCheck, 1, get4byte(&pBt->pPage1->aData[32]),
+              get4byte(&pBt->pPage1->aData[36]));
+    sCheck.zPfx = 0;
+  }
+
+  /* Check all the tables.
+  */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  if( !bPartial ){
+    if( pBt->autoVacuum ){
+      Pgno mx = 0;
+      Pgno mxInHdr;
+      for(i=0; (int)i<nRoot; i++) if( mx<aRoot[i] ) mx = aRoot[i];
+      mxInHdr = get4byte(&pBt->pPage1->aData[52]);
+      if( mx!=mxInHdr ){
+        checkAppendMsg(&sCheck,
+          "max rootpage (%u) disagrees with header (%u)",
+          mx, mxInHdr
+        );
+      }
+    }else if( get4byte(&pBt->pPage1->aData[64])!=0 ){
+      checkAppendMsg(&sCheck,
+        "incremental_vacuum enabled with a max rootpage of zero"
+      );
+    }
+  }
+#endif
+  testcase( pBt->db->flags & SQLITE_CellSizeCk );
+  pBt->db->flags &= ~(u64)SQLITE_CellSizeCk;
+  for(i=0; (int)i<nRoot && sCheck.mxErr; i++){
+    sCheck.nRow = 0;
+    if( aRoot[i] ){
+      i64 notUsed;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pBt->autoVacuum && aRoot[i]>1 && !bPartial ){
+        checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0);
+      }
+#endif
+      sCheck.v0 = aRoot[i];
+      checkTreePage(&sCheck, aRoot[i], ¬Used, LARGEST_INT64);
+    }
+    sqlite3MemSetArrayInt64(aCnt, i, sCheck.nRow);
+  }
+  pBt->db->flags = savedDbFlags;
+
+  /* Make sure every page in the file is referenced
+  */
+  if( !bPartial ){
+    for(i=1; i<=sCheck.nCkPage && sCheck.mxErr; i++){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+      if( getPageReferenced(&sCheck, i)==0 ){
+        checkAppendMsg(&sCheck, "Page %u: never used", i);
+      }
+#else
+      /* If the database supports auto-vacuum, make sure no tables contain
+      ** references to pointer-map pages.
+      */
+      if( getPageReferenced(&sCheck, i)==0 &&
+         (PTRMAP_PAGENO(pBt, i)!=i || !pBt->autoVacuum) ){
+        checkAppendMsg(&sCheck, "Page %u: never used", i);
+      }
+      if( getPageReferenced(&sCheck, i)!=0 &&
+         (PTRMAP_PAGENO(pBt, i)==i && pBt->autoVacuum) ){
+        checkAppendMsg(&sCheck, "Page %u: pointer map referenced", i);
+      }
+#endif
+    }
+  }
+
+  /* Clean  up and report errors.
+  */
+integrity_ck_cleanup:
+  sqlite3PageFree(sCheck.heap);
+  sqlite3_free(sCheck.aPgRef);
+  *pnErr = sCheck.nErr;
+  if( sCheck.nErr==0 ){
+    sqlite3_str_reset(&sCheck.errMsg);
+    *pzOut = 0;
+  }else{
+    *pzOut = sqlite3StrAccumFinish(&sCheck.errMsg);
+  }
+  /* Make sure this analysis did not leave any unref() pages. */
+  assert( nRef==sqlite3PagerRefcount(pBt->pPager) );
+  sqlite3BtreeLeave(p);
+  return sCheck.rc;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+/*
+** Return the full pathname of the underlying database file.  Return
+** an empty string if the database is in-memory or a TEMP database.
+**
+** The pager filename is invariant as long as the pager is
+** open so it is safe to access without the BtShared mutex.
+*/
+SQLITE_PRIVATE const char *sqlite3BtreeGetFilename(Btree *p){
+  assert( p->pBt->pPager!=0 );
+  return sqlite3PagerFilename(p->pBt->pPager, 1);
+}
+
+/*
+** Return the pathname of the journal file for this database. The return
+** value of this routine is the same regardless of whether the journal file
+** has been created or not.
+**
+** The pager journal filename is invariant as long as the pager is
+** open so it is safe to access without the BtShared mutex.
+*/
+SQLITE_PRIVATE const char *sqlite3BtreeGetJournalname(Btree *p){
+  assert( p->pBt->pPager!=0 );
+  return sqlite3PagerJournalname(p->pBt->pPager);
+}
+
+/*
+** Return one of SQLITE_TXN_NONE, SQLITE_TXN_READ, or SQLITE_TXN_WRITE
+** to describe the current transaction state of Btree p.
+*/
+SQLITE_PRIVATE int sqlite3BtreeTxnState(Btree *p){
+  assert( p==0 || sqlite3_mutex_held(p->db->mutex) );
+  return p ? p->inTrans : 0;
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** Run a checkpoint on the Btree passed as the first argument.
+**
+** Return SQLITE_LOCKED if this or any other connection has an open
+** transaction on the shared-cache the argument Btree is connected to.
+**
+** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCheckpoint(Btree *p, int eMode, int *pnLog, int *pnCkpt){
+  int rc = SQLITE_OK;
+  if( p ){
+    BtShared *pBt = p->pBt;
+    sqlite3BtreeEnter(p);
+    if( pBt->inTransaction!=TRANS_NONE ){
+      rc = SQLITE_LOCKED;
+    }else{
+      rc = sqlite3PagerCheckpoint(pBt->pPager, p->db, eMode, pnLog, pnCkpt);
+    }
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+#endif
+
+/*
+** Return true if there is currently a backup running on Btree p.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIsInBackup(Btree *p){
+  assert( p );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  return p->nBackup!=0;
+}
+
+/*
+** This function returns a pointer to a blob of memory associated with
+** a single shared-btree. The memory is used by client code for its own
+** purposes (for example, to store a high-level schema associated with
+** the shared-btree). The btree layer manages reference counting issues.
+**
+** The first time this is called on a shared-btree, nBytes bytes of memory
+** are allocated, zeroed, and returned to the caller. For each subsequent
+** call the nBytes parameter is ignored and a pointer to the same blob
+** of memory returned.
+**
+** If the nBytes parameter is 0 and the blob of memory has not yet been
+** allocated, a null pointer is returned. If the blob has already been
+** allocated, it is returned as normal.
+**
+** Just before the shared-btree is closed, the function passed as the
+** xFree argument when the memory allocation was made is invoked on the
+** blob of allocated memory. The xFree function should not call sqlite3_free()
+** on the memory, the btree layer does that.
+*/
+SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *p, int nBytes, void(*xFree)(void *)){
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  if( !pBt->pSchema && nBytes ){
+    pBt->pSchema = sqlite3DbMallocZero(0, nBytes);
+    pBt->xFreeSchema = xFree;
+  }
+  sqlite3BtreeLeave(p);
+  return pBt->pSchema;
+}
+
+/*
+** Return SQLITE_LOCKED_SHAREDCACHE if another user of the same shared
+** btree as the argument handle holds an exclusive lock on the
+** sqlite_schema table. Otherwise SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *p){
+  int rc;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  rc = querySharedCacheTableLock(p, SCHEMA_ROOT, READ_LOCK);
+  assert( rc==SQLITE_OK || rc==SQLITE_LOCKED_SHAREDCACHE );
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Obtain a lock on the table whose root page is iTab.  The
+** lock is a write lock if isWritelock is true or a read lock
+** if it is false.
+*/
+SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *p, int iTab, u8 isWriteLock){
+  int rc = SQLITE_OK;
+  assert( p->inTrans!=TRANS_NONE );
+  if( p->sharable ){
+    u8 lockType = READ_LOCK + isWriteLock;
+    assert( READ_LOCK+1==WRITE_LOCK );
+    assert( isWriteLock==0 || isWriteLock==1 );
+
+    sqlite3BtreeEnter(p);
+    rc = querySharedCacheTableLock(p, iTab, lockType);
+    if( rc==SQLITE_OK ){
+      rc = setSharedCacheTableLock(p, iTab, lockType);
+    }
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+#endif
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** Argument pCsr must be a cursor opened for writing on an
+** INTKEY table currently pointing at a valid table entry.
+** This function modifies the data stored as part of that entry.
+**
+** Only the data content may only be modified, it is not possible to
+** change the length of the data stored. If this function is called with
+** parameters that attempt to write past the end of the existing data,
+** no modifications are made and SQLITE_CORRUPT is returned.
+*/
+SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void *z){
+  int rc;
+  assert( cursorOwnsBtShared(pCsr) );
+  assert( sqlite3_mutex_held(pCsr->pBtree->db->mutex) );
+  assert( pCsr->curFlags & BTCF_Incrblob );
+
+  rc = restoreCursorPosition(pCsr);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  assert( pCsr->eState!=CURSOR_REQUIRESEEK );
+  if( pCsr->eState!=CURSOR_VALID ){
+    return SQLITE_ABORT;
+  }
+
+  /* Save the positions of all other cursors open on this table. This is
+  ** required in case any of them are holding references to an xFetch
+  ** version of the b-tree page modified by the accessPayload call below.
+  **
+  ** Note that pCsr must be open on a INTKEY table and saveCursorPosition()
+  ** and hence saveAllCursors() cannot fail on a BTREE_INTKEY table, hence
+  ** saveAllCursors can only return SQLITE_OK.
+  */
+  VVA_ONLY(rc =) saveAllCursors(pCsr->pBt, pCsr->pgnoRoot, pCsr);
+  assert( rc==SQLITE_OK );
+
+  /* Check some assumptions:
+  **   (a) the cursor is open for writing,
+  **   (b) there is a read/write transaction open,
+  **   (c) the connection holds a write-lock on the table (if required),
+  **   (d) there are no conflicting read-locks, and
+  **   (e) the cursor points at a valid row of an intKey table.
+  */
+  if( (pCsr->curFlags & BTCF_WriteFlag)==0 ){
+    return SQLITE_READONLY;
+  }
+  assert( (pCsr->pBt->btsFlags & BTS_READ_ONLY)==0
+              && pCsr->pBt->inTransaction==TRANS_WRITE );
+  assert( hasSharedCacheTableLock(pCsr->pBtree, pCsr->pgnoRoot, 0, 2) );
+  assert( !hasReadConflicts(pCsr->pBtree, pCsr->pgnoRoot) );
+  assert( pCsr->pPage->intKey );
+
+  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 1);
+}
+
+/*
+** Mark this cursor as an incremental blob cursor.
+*/
+SQLITE_PRIVATE void sqlite3BtreeIncrblobCursor(BtCursor *pCur){
+  pCur->curFlags |= BTCF_Incrblob;
+  pCur->pBtree->hasIncrblobCur = 1;
+}
+#endif
+
+/*
+** Set both the "read version" (single byte at byte offset 18) and
+** "write version" (single byte at byte offset 19) fields in the database
+** header to iVersion.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
+  BtShared *pBt = pBtree->pBt;
+  int rc;                         /* Return code */
+
+  assert( iVersion==1 || iVersion==2 );
+
+  /* If setting the version fields to 1, do not automatically open the
+  ** WAL connection, even if the version fields are currently set to 2.
+  */
+  pBt->btsFlags &= ~BTS_NO_WAL;
+  if( iVersion==1 ) pBt->btsFlags |= BTS_NO_WAL;
+
+  rc = sqlite3BtreeBeginTrans(pBtree, 0, 0);
+  if( rc==SQLITE_OK ){
+    u8 *aData = pBt->pPage1->aData;
+    if( aData[18]!=(u8)iVersion || aData[19]!=(u8)iVersion ){
+      rc = sqlite3BtreeBeginTrans(pBtree, 2, 0);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+        if( rc==SQLITE_OK ){
+          aData[18] = (u8)iVersion;
+          aData[19] = (u8)iVersion;
+        }
+      }
+    }
+  }
+
+  pBt->btsFlags &= ~BTS_NO_WAL;
+  return rc;
+}
+
+/*
+** Return true if the cursor has a hint specified.  This routine is
+** only used from within assert() statements
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorHasHint(BtCursor *pCsr, unsigned int mask){
+  return (pCsr->hints & mask)!=0;
+}
+
+/*
+** Return true if the given Btree is read-only.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIsReadonly(Btree *p){
+  return (p->pBt->btsFlags & BTS_READ_ONLY)!=0;
+}
+
+/*
+** Return the size of the header added to each page by this module.
+*/
+SQLITE_PRIVATE int sqlite3HeaderSizeBtree(void){ return ROUND8(sizeof(MemPage)); }
+
+/*
+** If no transaction is active and the database is not a temp-db, clear
+** the in-memory pager cache.
+*/
+SQLITE_PRIVATE void sqlite3BtreeClearCache(Btree *p){
+  BtShared *pBt = p->pBt;
+  if( pBt->inTransaction==TRANS_NONE ){
+    sqlite3PagerClearCache(pBt->pPager);
+  }
+}
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE)
+/*
+** Return true if the Btree passed as the only argument is sharable.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSharable(Btree *p){
+  return p->sharable;
+}
+
+/*
+** Return the number of connections to the BtShared object accessed by
+** the Btree handle passed as the only argument. For private caches
+** this is always 1. For shared caches it may be 1 or greater.
+*/
+SQLITE_PRIVATE int sqlite3BtreeConnectionCount(Btree *p){
+  testcase( p->sharable );
+  return p->pBt->nRef;
+}
+#endif
+
+/************** End of btree.c ***********************************************/
+/************** Begin file backup.c ******************************************/
+/*
+** 2009 January 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the implementation of the sqlite3_backup_XXX()
+** API functions and the related features.
+*/
+/* #include "sqliteInt.h" */
+/* #include "btreeInt.h" */
+
+/*
+** Structure allocated for each backup operation.
+*/
+struct sqlite3_backup {
+  sqlite3* pDestDb;        /* Destination database handle */
+  Btree *pDest;            /* Destination b-tree file */
+  u32 iDestSchema;         /* Original schema cookie in destination */
+  int bDestLocked;         /* True once a write-transaction is open on pDest */
+
+  Pgno iNext;              /* Page number of the next source page to copy */
+  sqlite3* pSrcDb;         /* Source database handle */
+  Btree *pSrc;             /* Source b-tree file */
+
+  int rc;                  /* Backup process error code */
+
+  /* These two variables are set by every call to backup_step(). They are
+  ** read by calls to backup_remaining() and backup_pagecount().
+  */
+  Pgno nRemaining;         /* Number of pages left to copy */
+  Pgno nPagecount;         /* Total number of pages to copy */
+
+  int isAttached;          /* True once backup has been registered with pager */
+  sqlite3_backup *pNext;   /* Next backup associated with source pager */
+};
+
+/*
+** THREAD SAFETY NOTES:
+**
+**   Once it has been created using backup_init(), a single sqlite3_backup
+**   structure may be accessed via two groups of thread-safe entry points:
+**
+**     * Via the sqlite3_backup_XXX() API function backup_step() and
+**       backup_finish(). Both these functions obtain the source database
+**       handle mutex and the mutex associated with the source BtShared
+**       structure, in that order.
+**
+**     * Via the BackupUpdate() and BackupRestart() functions, which are
+**       invoked by the pager layer to report various state changes in
+**       the page cache associated with the source database. The mutex
+**       associated with the source database BtShared structure will always
+**       be held when either of these functions are invoked.
+**
+**   The other sqlite3_backup_XXX() API functions, backup_remaining() and
+**   backup_pagecount() are not thread-safe functions. If they are called
+**   while some other thread is calling backup_step() or backup_finish(),
+**   the values returned may be invalid. There is no way for a call to
+**   BackupUpdate() or BackupRestart() to interfere with backup_remaining()
+**   or backup_pagecount().
+**
+**   Depending on the SQLite configuration, the database handles and/or
+**   the Btree objects may have their own mutexes that require locking.
+**   Non-sharable Btrees (in-memory databases for example), do not have
+**   associated mutexes.
+*/
+
+/*
+** Return a pointer corresponding to database zDb (i.e. "main", "temp")
+** in connection handle pDb. If such a database cannot be found, return
+** a NULL pointer and write an error message to pErrorDb.
+**
+** If the "temp" database is requested, it may need to be opened by this
+** function. If an error occurs while doing so, return 0 and write an
+** error message to pErrorDb.
+*/
+static Btree *findBtree(sqlite3 *pErrorDb, sqlite3 *pDb, const char *zDb){
+  int i = sqlite3FindDbName(pDb, zDb);
+
+  if( i==1 ){
+    Parse sParse;
+    int rc = 0;
+    sqlite3ParseObjectInit(&sParse,pDb);
+    if( sqlite3OpenTempDatabase(&sParse) ){
+      sqlite3ErrorWithMsg(pErrorDb, sParse.rc, "%s", sParse.zErrMsg);
+      rc = SQLITE_ERROR;
+    }
+    sqlite3DbFree(pErrorDb, sParse.zErrMsg);
+    sqlite3ParseObjectReset(&sParse);
+    if( rc ){
+      return 0;
+    }
+  }
+
+  if( i<0 ){
+    sqlite3ErrorWithMsg(pErrorDb, SQLITE_ERROR, "unknown database %s", zDb);
+    return 0;
+  }
+
+  return pDb->aDb[i].pBt;
+}
+
+/*
+** Attempt to set the page size of the destination to match the page size
+** of the source.
+*/
+static int setDestPgsz(sqlite3_backup *p){
+  int rc;
+  rc = sqlite3BtreeSetPageSize(p->pDest,sqlite3BtreeGetPageSize(p->pSrc),0,0);
+  return rc;
+}
+
+/*
+** Check that there is no open read-transaction on the b-tree passed as the
+** second argument. If there is not, return SQLITE_OK. Otherwise, if there
+** is an open read-transaction, return SQLITE_ERROR and leave an error
+** message in database handle db.
+*/
+static int checkReadTransaction(sqlite3 *db, Btree *p){
+  if( sqlite3BtreeTxnState(p)!=SQLITE_TXN_NONE ){
+    sqlite3ErrorWithMsg(db, SQLITE_ERROR, "destination database is in use");
+    return SQLITE_ERROR;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Create an sqlite3_backup process to copy the contents of zSrcDb from
+** connection handle pSrcDb to zDestDb in pDestDb. If successful, return
+** a pointer to the new sqlite3_backup object.
+**
+** If an error occurs, NULL is returned and an error code and error message
+** stored in database handle pDestDb.
+*/
+SQLITE_API sqlite3_backup *sqlite3_backup_init(
+  sqlite3* pDestDb,                     /* Database to write to */
+  const char *zDestDb,                  /* Name of database within pDestDb */
+  sqlite3* pSrcDb,                      /* Database connection to read from */
+  const char *zSrcDb                    /* Name of database within pSrcDb */
+){
+  sqlite3_backup *p;                    /* Value to return */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(pSrcDb)||!sqlite3SafetyCheckOk(pDestDb) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+
+  /* Lock the source database handle. The destination database
+  ** handle is not locked in this routine, but it is locked in
+  ** sqlite3_backup_step(). The user is required to ensure that no
+  ** other thread accesses the destination handle for the duration
+  ** of the backup operation.  Any attempt to use the destination
+  ** database connection while a backup is in progress may cause
+  ** a malfunction or a deadlock.
+  */
+  sqlite3_mutex_enter(pSrcDb->mutex);
+  sqlite3_mutex_enter(pDestDb->mutex);
+
+  if( pSrcDb==pDestDb ){
+    sqlite3ErrorWithMsg(
+        pDestDb, SQLITE_ERROR, "source and destination must be distinct"
+    );
+    p = 0;
+  }else {
+    /* Allocate space for a new sqlite3_backup object...
+    ** EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a
+    ** call to sqlite3_backup_init() and is destroyed by a call to
+    ** sqlite3_backup_finish(). */
+    p = (sqlite3_backup *)sqlite3MallocZero(sizeof(sqlite3_backup));
+    if( !p ){
+      sqlite3Error(pDestDb, SQLITE_NOMEM_BKPT);
+    }
+  }
+
+  /* If the allocation succeeded, populate the new object. */
+  if( p ){
+    p->pSrc = findBtree(pDestDb, pSrcDb, zSrcDb);
+    p->pDest = findBtree(pDestDb, pDestDb, zDestDb);
+    p->pDestDb = pDestDb;
+    p->pSrcDb = pSrcDb;
+    p->iNext = 1;
+    p->isAttached = 0;
+
+    if( 0==p->pSrc || 0==p->pDest
+     || checkReadTransaction(pDestDb, p->pDest)!=SQLITE_OK
+     ){
+      /* One (or both) of the named databases did not exist or an OOM
+      ** error was hit. Or there is a transaction open on the destination
+      ** database. The error has already been written into the pDestDb
+      ** handle. All that is left to do here is free the sqlite3_backup
+      ** structure.  */
+      sqlite3_free(p);
+      p = 0;
+    }
+  }
+  if( p ){
+    p->pSrc->nBackup++;
+  }
+
+  sqlite3_mutex_leave(pDestDb->mutex);
+  sqlite3_mutex_leave(pSrcDb->mutex);
+  return p;
+}
+
+/*
+** Argument rc is an SQLite error code. Return true if this error is
+** considered fatal if encountered during a backup operation. All errors
+** are considered fatal except for SQLITE_BUSY and SQLITE_LOCKED.
+*/
+static int isFatalError(int rc){
+  return (rc!=SQLITE_OK && rc!=SQLITE_BUSY && ALWAYS(rc!=SQLITE_LOCKED));
+}
+
+/*
+** Parameter zSrcData points to a buffer containing the data for
+** page iSrcPg from the source database. Copy this data into the
+** destination database.
+*/
+static int backupOnePage(
+  sqlite3_backup *p,              /* Backup handle */
+  Pgno iSrcPg,                    /* Source database page to backup */
+  const u8 *zSrcData,             /* Source database page data */
+  int bUpdate                     /* True for an update, false otherwise */
+){
+  Pager * const pDestPager = sqlite3BtreePager(p->pDest);
+  const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc);
+  int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest);
+  const int nCopy = MIN(nSrcPgsz, nDestPgsz);
+  const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz;
+  int rc = SQLITE_OK;
+  i64 iOff;
+
+  assert( sqlite3BtreeGetReserveNoMutex(p->pSrc)>=0 );
+  assert( p->bDestLocked );
+  assert( !isFatalError(p->rc) );
+  assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) );
+  assert( zSrcData );
+  assert( nSrcPgsz==nDestPgsz || sqlite3PagerIsMemdb(pDestPager)==0 );
+
+  /* This loop runs once for each destination page spanned by the source
+  ** page. For each iteration, variable iOff is set to the byte offset
+  ** of the destination page.
+  */
+  for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){
+    DbPage *pDestPg = 0;
+    Pgno iDest = (Pgno)(iOff/nDestPgsz)+1;
+    if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue;
+    if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg, 0))
+     && SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg))
+    ){
+      const u8 *zIn = &zSrcData[iOff%nSrcPgsz];
+      u8 *zDestData = sqlite3PagerGetData(pDestPg);
+      u8 *zOut = &zDestData[iOff%nDestPgsz];
+
+      /* Copy the data from the source page into the destination page.
+      ** Then clear the Btree layer MemPage.isInit flag. Both this module
+      ** and the pager code use this trick (clearing the first byte
+      ** of the page 'extra' space to invalidate the Btree layers
+      ** cached parse of the page). MemPage.isInit is marked
+      ** "MUST BE FIRST" for this purpose.
+      */
+      memcpy(zOut, zIn, nCopy);
+      ((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0;
+      if( iOff==0 && bUpdate==0 ){
+        sqlite3Put4byte(&zOut[28], sqlite3BtreeLastPage(p->pSrc));
+      }
+    }
+    sqlite3PagerUnref(pDestPg);
+  }
+
+  return rc;
+}
+
+/*
+** If pFile is currently larger than iSize bytes, then truncate it to
+** exactly iSize bytes. If pFile is not larger than iSize bytes, then
+** this function is a no-op.
+**
+** Return SQLITE_OK if everything is successful, or an SQLite error
+** code if an error occurs.
+*/
+static int backupTruncateFile(sqlite3_file *pFile, i64 iSize){
+  i64 iCurrent;
+  int rc = sqlite3OsFileSize(pFile, &iCurrent);
+  if( rc==SQLITE_OK && iCurrent>iSize ){
+    rc = sqlite3OsTruncate(pFile, iSize);
+  }
+  return rc;
+}
+
+/*
+** Register this backup object with the associated source pager for
+** callbacks when pages are changed or the cache invalidated.
+*/
+static void attachBackupObject(sqlite3_backup *p){
+  sqlite3_backup **pp;
+  assert( sqlite3BtreeHoldsMutex(p->pSrc) );
+  pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
+  p->pNext = *pp;
+  *pp = p;
+  p->isAttached = 1;
+}
+
+/*
+** Copy nPage pages from the source b-tree to the destination.
+*/
+SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage){
+  int rc;
+  int destMode;       /* Destination journal mode */
+  int pgszSrc = 0;    /* Source page size */
+  int pgszDest = 0;   /* Destination page size */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(p->pSrcDb->mutex);
+  sqlite3BtreeEnter(p->pSrc);
+  if( p->pDestDb ){
+    sqlite3_mutex_enter(p->pDestDb->mutex);
+  }
+
+  rc = p->rc;
+  if( !isFatalError(rc) ){
+    Pager * const pSrcPager = sqlite3BtreePager(p->pSrc);     /* Source pager */
+    Pager * const pDestPager = sqlite3BtreePager(p->pDest);   /* Dest pager */
+    int ii;                            /* Iterator variable */
+    int nSrcPage = -1;                 /* Size of source db in pages */
+    int bCloseTrans = 0;               /* True if src db requires unlocking */
+
+    /* If the source pager is currently in a write-transaction, return
+    ** SQLITE_BUSY immediately.
+    */
+    if( p->pDestDb && p->pSrc->pBt->inTransaction==TRANS_WRITE ){
+      rc = SQLITE_BUSY;
+    }else{
+      rc = SQLITE_OK;
+    }
+
+    /* If there is no open read-transaction on the source database, open
+    ** one now. If a transaction is opened here, then it will be closed
+    ** before this function exits.
+    */
+    if( rc==SQLITE_OK && SQLITE_TXN_NONE==sqlite3BtreeTxnState(p->pSrc) ){
+      rc = sqlite3BtreeBeginTrans(p->pSrc, 0, 0);
+      bCloseTrans = 1;
+    }
+
+    /* If the destination database has not yet been locked (i.e. if this
+    ** is the first call to backup_step() for the current backup operation),
+    ** try to set its page size to the same as the source database. This
+    ** is especially important on ZipVFS systems, as in that case it is
+    ** not possible to create a database file that uses one page size by
+    ** writing to it with another.  */
+    if( p->bDestLocked==0 && rc==SQLITE_OK && setDestPgsz(p)==SQLITE_NOMEM ){
+      rc = SQLITE_NOMEM;
+    }
+
+    /* Lock the destination database, if it is not locked already. */
+    if( SQLITE_OK==rc && p->bDestLocked==0
+     && SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2,
+                                                (int*)&p->iDestSchema))
+    ){
+      p->bDestLocked = 1;
+    }
+
+    /* Do not allow backup if the destination database is in WAL mode
+    ** and the page sizes are different between source and destination */
+    pgszSrc = sqlite3BtreeGetPageSize(p->pSrc);
+    pgszDest = sqlite3BtreeGetPageSize(p->pDest);
+    destMode = sqlite3PagerGetJournalMode(sqlite3BtreePager(p->pDest));
+    if( SQLITE_OK==rc
+     && (destMode==PAGER_JOURNALMODE_WAL || sqlite3PagerIsMemdb(pDestPager))
+     && pgszSrc!=pgszDest
+    ){
+      rc = SQLITE_READONLY;
+    }
+
+    /* Now that there is a read-lock on the source database, query the
+    ** source pager for the number of pages in the database.
+    */
+    nSrcPage = (int)sqlite3BtreeLastPage(p->pSrc);
+    assert( nSrcPage>=0 );
+    for(ii=0; (nPage<0 || ii<nPage) && p->iNext<=(Pgno)nSrcPage && !rc; ii++){
+      const Pgno iSrcPg = p->iNext;                 /* Source page number */
+      if( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ){
+        DbPage *pSrcPg;                             /* Source page object */
+        rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg,PAGER_GET_READONLY);
+        if( rc==SQLITE_OK ){
+          rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg), 0);
+          sqlite3PagerUnref(pSrcPg);
+        }
+      }
+      p->iNext++;
+    }
+    if( rc==SQLITE_OK ){
+      p->nPagecount = nSrcPage;
+      p->nRemaining = nSrcPage+1-p->iNext;
+      if( p->iNext>(Pgno)nSrcPage ){
+        rc = SQLITE_DONE;
+      }else if( !p->isAttached ){
+        attachBackupObject(p);
+      }
+    }
+
+    /* Update the schema version field in the destination database. This
+    ** is to make sure that the schema-version really does change in
+    ** the case where the source and destination databases have the
+    ** same schema version.
+    */
+    if( rc==SQLITE_DONE ){
+      if( nSrcPage==0 ){
+        rc = sqlite3BtreeNewDb(p->pDest);
+        nSrcPage = 1;
+      }
+      if( rc==SQLITE_OK || rc==SQLITE_DONE ){
+        rc = sqlite3BtreeUpdateMeta(p->pDest,1,p->iDestSchema+1);
+      }
+      if( rc==SQLITE_OK ){
+        if( p->pDestDb ){
+          sqlite3ResetAllSchemasOfConnection(p->pDestDb);
+        }
+        if( destMode==PAGER_JOURNALMODE_WAL ){
+          rc = sqlite3BtreeSetVersion(p->pDest, 2);
+        }
+      }
+      if( rc==SQLITE_OK ){
+        int nDestTruncate;
+        /* Set nDestTruncate to the final number of pages in the destination
+        ** database. The complication here is that the destination page
+        ** size may be different to the source page size.
+        **
+        ** If the source page size is smaller than the destination page size,
+        ** round up. In this case the call to sqlite3OsTruncate() below will
+        ** fix the size of the file. However it is important to call
+        ** sqlite3PagerTruncateImage() here so that any pages in the
+        ** destination file that lie beyond the nDestTruncate page mark are
+        ** journalled by PagerCommitPhaseOne() before they are destroyed
+        ** by the file truncation.
+        */
+        assert( pgszSrc==sqlite3BtreeGetPageSize(p->pSrc) );
+        assert( pgszDest==sqlite3BtreeGetPageSize(p->pDest) );
+        if( pgszSrc<pgszDest ){
+          int ratio = pgszDest/pgszSrc;
+          nDestTruncate = (nSrcPage+ratio-1)/ratio;
+          if( nDestTruncate==(int)PENDING_BYTE_PAGE(p->pDest->pBt) ){
+            nDestTruncate--;
+          }
+        }else{
+          nDestTruncate = nSrcPage * (pgszSrc/pgszDest);
+        }
+        assert( nDestTruncate>0 );
+
+        if( pgszSrc<pgszDest ){
+          /* If the source page-size is smaller than the destination page-size,
+          ** two extra things may need to happen:
+          **
+          **   * The destination may need to be truncated, and
+          **
+          **   * Data stored on the pages immediately following the
+          **     pending-byte page in the source database may need to be
+          **     copied into the destination database.
+          */
+          const i64 iSize = (i64)pgszSrc * (i64)nSrcPage;
+          sqlite3_file * const pFile = sqlite3PagerFile(pDestPager);
+          Pgno iPg;
+          int nDstPage;
+          i64 iOff;
+          i64 iEnd;
+
+          assert( pFile );
+          assert( nDestTruncate==0
+              || (i64)nDestTruncate*(i64)pgszDest >= iSize || (
+                nDestTruncate==(int)(PENDING_BYTE_PAGE(p->pDest->pBt)-1)
+             && iSize>=PENDING_BYTE && iSize<=PENDING_BYTE+pgszDest
+          ));
+
+          /* This block ensures that all data required to recreate the original
+          ** database has been stored in the journal for pDestPager and the
+          ** journal synced to disk. So at this point we may safely modify
+          ** the database file in any way, knowing that if a power failure
+          ** occurs, the original database will be reconstructed from the
+          ** journal file.  */
+          sqlite3PagerPagecount(pDestPager, &nDstPage);
+          for(iPg=nDestTruncate; rc==SQLITE_OK && iPg<=(Pgno)nDstPage; iPg++){
+            if( iPg!=PENDING_BYTE_PAGE(p->pDest->pBt) ){
+              DbPage *pPg;
+              rc = sqlite3PagerGet(pDestPager, iPg, &pPg, 0);
+              if( rc==SQLITE_OK ){
+                rc = sqlite3PagerWrite(pPg);
+                sqlite3PagerUnref(pPg);
+              }
+            }
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 1);
+          }
+
+          /* Write the extra pages and truncate the database file as required */
+          iEnd = MIN(PENDING_BYTE + pgszDest, iSize);
+          for(
+            iOff=PENDING_BYTE+pgszSrc;
+            rc==SQLITE_OK && iOff<iEnd;
+            iOff+=pgszSrc
+          ){
+            PgHdr *pSrcPg = 0;
+            const Pgno iSrcPg = (Pgno)((iOff/pgszSrc)+1);
+            rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg, 0);
+            if( rc==SQLITE_OK ){
+              u8 *zData = sqlite3PagerGetData(pSrcPg);
+              rc = sqlite3OsWrite(pFile, zData, pgszSrc, iOff);
+            }
+            sqlite3PagerUnref(pSrcPg);
+          }
+          if( rc==SQLITE_OK ){
+            rc = backupTruncateFile(pFile, iSize);
+          }
+
+          /* Sync the database file to disk. */
+          if( rc==SQLITE_OK ){
+            rc = sqlite3PagerSync(pDestPager, 0);
+          }
+        }else{
+          sqlite3PagerTruncateImage(pDestPager, nDestTruncate);
+          rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 0);
+        }
+
+        /* Finish committing the transaction to the destination database. */
+        if( SQLITE_OK==rc
+         && SQLITE_OK==(rc = sqlite3BtreeCommitPhaseTwo(p->pDest, 0))
+        ){
+          rc = SQLITE_DONE;
+        }
+      }
+    }
+
+    /* If bCloseTrans is true, then this function opened a read transaction
+    ** on the source database. Close the read transaction here. There is
+    ** no need to check the return values of the btree methods here, as
+    ** "committing" a read-only transaction cannot fail.
+    */
+    if( bCloseTrans ){
+      TESTONLY( int rc2 );
+      TESTONLY( rc2  = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0);
+      TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc, 0);
+      assert( rc2==SQLITE_OK );
+    }
+
+    if( rc==SQLITE_IOERR_NOMEM ){
+      rc = SQLITE_NOMEM_BKPT;
+    }
+    p->rc = rc;
+  }
+  if( p->pDestDb ){
+    sqlite3_mutex_leave(p->pDestDb->mutex);
+  }
+  sqlite3BtreeLeave(p->pSrc);
+  sqlite3_mutex_leave(p->pSrcDb->mutex);
+  return rc;
+}
+
+/*
+** Release all resources associated with an sqlite3_backup* handle.
+*/
+SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p){
+  sqlite3_backup **pp;                 /* Ptr to head of pagers backup list */
+  sqlite3 *pSrcDb;                     /* Source database connection */
+  int rc;                              /* Value to return */
+
+  /* Enter the mutexes */
+  if( p==0 ) return SQLITE_OK;
+  pSrcDb = p->pSrcDb;
+  sqlite3_mutex_enter(pSrcDb->mutex);
+  sqlite3BtreeEnter(p->pSrc);
+  if( p->pDestDb ){
+    sqlite3_mutex_enter(p->pDestDb->mutex);
+  }
+
+  /* Detach this backup from the source pager. */
+  if( p->pDestDb ){
+    p->pSrc->nBackup--;
+  }
+  if( p->isAttached ){
+    pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
+    assert( pp!=0 );
+    while( *pp!=p ){
+      pp = &(*pp)->pNext;
+      assert( pp!=0 );
+    }
+    *pp = p->pNext;
+  }
+
+  /* If a transaction is still open on the Btree, roll it back. */
+  sqlite3BtreeRollback(p->pDest, SQLITE_OK, 0);
+
+  /* Set the error code of the destination database handle. */
+  rc = (p->rc==SQLITE_DONE) ? SQLITE_OK : p->rc;
+  if( p->pDestDb ){
+    sqlite3Error(p->pDestDb, rc);
+
+    /* Exit the mutexes and free the backup context structure. */
+    sqlite3LeaveMutexAndCloseZombie(p->pDestDb);
+  }
+  sqlite3BtreeLeave(p->pSrc);
+  if( p->pDestDb ){
+    /* EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a
+    ** call to sqlite3_backup_init() and is destroyed by a call to
+    ** sqlite3_backup_finish(). */
+    sqlite3_free(p);
+  }
+  sqlite3LeaveMutexAndCloseZombie(pSrcDb);
+  return rc;
+}
+
+/*
+** Return the number of pages still to be backed up as of the most recent
+** call to sqlite3_backup_step().
+*/
+SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return p->nRemaining;
+}
+
+/*
+** Return the total number of pages in the source database as of the most
+** recent call to sqlite3_backup_step().
+*/
+SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return p->nPagecount;
+}
+
+/*
+** This function is called after the contents of page iPage of the
+** source database have been modified. If page iPage has already been
+** copied into the destination database, then the data written to the
+** destination is now invalidated. The destination copy of iPage needs
+** to be updated with the new data before the backup operation is
+** complete.
+**
+** It is assumed that the mutex associated with the BtShared object
+** corresponding to the source database is held when this function is
+** called.
+*/
+static SQLITE_NOINLINE void backupUpdate(
+  sqlite3_backup *p,
+  Pgno iPage,
+  const u8 *aData
+){
+  assert( p!=0 );
+  do{
+    assert( sqlite3_mutex_held(p->pSrc->pBt->mutex) );
+    if( !isFatalError(p->rc) && iPage<p->iNext ){
+      /* The backup process p has already copied page iPage. But now it
+      ** has been modified by a transaction on the source pager. Copy
+      ** the new data into the backup.
+      */
+      int rc;
+      assert( p->pDestDb );
+      sqlite3_mutex_enter(p->pDestDb->mutex);
+      rc = backupOnePage(p, iPage, aData, 1);
+      sqlite3_mutex_leave(p->pDestDb->mutex);
+      assert( rc!=SQLITE_BUSY && rc!=SQLITE_LOCKED );
+      if( rc!=SQLITE_OK ){
+        p->rc = rc;
+      }
+    }
+  }while( (p = p->pNext)!=0 );
+}
+SQLITE_PRIVATE void sqlite3BackupUpdate(sqlite3_backup *pBackup, Pgno iPage, const u8 *aData){
+  if( pBackup ) backupUpdate(pBackup, iPage, aData);
+}
+
+/*
+** Restart the backup process. This is called when the pager layer
+** detects that the database has been modified by an external database
+** connection. In this case there is no way of knowing which of the
+** pages that have been copied into the destination database are still
+** valid and which are not, so the entire process needs to be restarted.
+**
+** It is assumed that the mutex associated with the BtShared object
+** corresponding to the source database is held when this function is
+** called.
+*/
+SQLITE_PRIVATE void sqlite3BackupRestart(sqlite3_backup *pBackup){
+  sqlite3_backup *p;                   /* Iterator variable */
+  for(p=pBackup; p; p=p->pNext){
+    assert( sqlite3_mutex_held(p->pSrc->pBt->mutex) );
+    p->iNext = 1;
+  }
+}
+
+#ifndef SQLITE_OMIT_VACUUM
+/*
+** Copy the complete content of pBtFrom into pBtTo.  A transaction
+** must be active for both files.
+**
+** The size of file pTo may be reduced by this operation. If anything
+** goes wrong, the transaction on pTo is rolled back. If successful, the
+** transaction is committed before returning.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){
+  int rc;
+  sqlite3_file *pFd;              /* File descriptor for database pTo */
+  sqlite3_backup b;
+  sqlite3BtreeEnter(pTo);
+  sqlite3BtreeEnter(pFrom);
+
+  assert( sqlite3BtreeTxnState(pTo)==SQLITE_TXN_WRITE );
+  pFd = sqlite3PagerFile(sqlite3BtreePager(pTo));
+  if( pFd->pMethods ){
+    i64 nByte = sqlite3BtreeGetPageSize(pFrom)*(i64)sqlite3BtreeLastPage(pFrom);
+    rc = sqlite3OsFileControl(pFd, SQLITE_FCNTL_OVERWRITE, &nByte);
+    if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+    if( rc ) goto copy_finished;
+  }
+
+  /* Set up an sqlite3_backup object. sqlite3_backup.pDestDb must be set
+  ** to 0. This is used by the implementations of sqlite3_backup_step()
+  ** and sqlite3_backup_finish() to detect that they are being called
+  ** from this function, not directly by the user.
+  */
+  memset(&b, 0, sizeof(b));
+  b.pSrcDb = pFrom->db;
+  b.pSrc = pFrom;
+  b.pDest = pTo;
+  b.iNext = 1;
+
+  /* 0x7FFFFFFF is the hard limit for the number of pages in a database
+  ** file. By passing this as the number of pages to copy to
+  ** sqlite3_backup_step(), we can guarantee that the copy finishes
+  ** within a single call (unless an error occurs). The assert() statement
+  ** checks this assumption - (p->rc) should be set to either SQLITE_DONE
+  ** or an error code.  */
+  sqlite3_backup_step(&b, 0x7FFFFFFF);
+  assert( b.rc!=SQLITE_OK );
+
+  rc = sqlite3_backup_finish(&b);
+  if( rc==SQLITE_OK ){
+    pTo->pBt->btsFlags &= ~BTS_PAGESIZE_FIXED;
+  }else{
+    sqlite3PagerClearCache(sqlite3BtreePager(b.pDest));
+  }
+
+  assert( sqlite3BtreeTxnState(pTo)!=SQLITE_TXN_WRITE );
+copy_finished:
+  sqlite3BtreeLeave(pFrom);
+  sqlite3BtreeLeave(pTo);
+  return rc;
+}
+#endif /* SQLITE_OMIT_VACUUM */
+
+/************** End of backup.c **********************************************/
+/************** Begin file vdbemem.c *****************************************/
+/*
+** 2004 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code use to manipulate "Mem" structure.  A "Mem"
+** stores a single value in the VDBE.  Mem is an opaque structure visible
+** only within the VDBE.  Interface routines refer to a Mem using the
+** name sqlite_value
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+/* True if X is a power of two.  0 is considered a power of two here.
+** In other words, return true if X has at most one bit set.
+*/
+#define ISPOWEROF2(X)  (((X)&((X)-1))==0)
+
+#ifdef SQLITE_DEBUG
+/*
+** Check invariants on a Mem object.
+**
+** This routine is intended for use inside of assert() statements, like
+** this:    assert( sqlite3VdbeCheckMemInvariants(pMem) );
+*/
+SQLITE_PRIVATE int sqlite3VdbeCheckMemInvariants(Mem *p){
+  /* If MEM_Dyn is set then Mem.xDel!=0.
+  ** Mem.xDel might not be initialized if MEM_Dyn is clear.
+  */
+  assert( (p->flags & MEM_Dyn)==0 || p->xDel!=0 );
+
+  /* MEM_Dyn may only be set if Mem.szMalloc==0.  In this way we
+  ** ensure that if Mem.szMalloc>0 then it is safe to do
+  ** Mem.z = Mem.zMalloc without having to check Mem.flags&MEM_Dyn.
+  ** That saves a few cycles in inner loops. */
+  assert( (p->flags & MEM_Dyn)==0 || p->szMalloc==0 );
+
+  /* Cannot have more than one of MEM_Int, MEM_Real, or MEM_IntReal */
+  assert( ISPOWEROF2(p->flags & (MEM_Int|MEM_Real|MEM_IntReal)) );
+
+  if( p->flags & MEM_Null ){
+    /* Cannot be both MEM_Null and some other type */
+    assert( (p->flags & (MEM_Int|MEM_Real|MEM_Str|MEM_Blob|MEM_Agg))==0 );
+
+    /* If MEM_Null is set, then either the value is a pure NULL (the usual
+    ** case) or it is a pointer set using sqlite3_bind_pointer() or
+    ** sqlite3_result_pointer().  If a pointer, then MEM_Term must also be
+    ** set.
+    */
+    if( (p->flags & (MEM_Term|MEM_Subtype))==(MEM_Term|MEM_Subtype) ){
+      /* This is a pointer type.  There may be a flag to indicate what to
+      ** do with the pointer. */
+      assert( ((p->flags&MEM_Dyn)!=0 ? 1 : 0) +
+              ((p->flags&MEM_Ephem)!=0 ? 1 : 0) +
+              ((p->flags&MEM_Static)!=0 ? 1 : 0) <= 1 );
+
+      /* No other bits set */
+      assert( (p->flags & ~(MEM_Null|MEM_Term|MEM_Subtype|MEM_FromBind
+                           |MEM_Dyn|MEM_Ephem|MEM_Static))==0 );
+    }else{
+      /* A pure NULL might have other flags, such as MEM_Static, MEM_Dyn,
+      ** MEM_Ephem, MEM_Cleared, or MEM_Subtype */
+    }
+  }else{
+    /* The MEM_Cleared bit is only allowed on NULLs */
+    assert( (p->flags & MEM_Cleared)==0 );
+  }
+
+  /* The szMalloc field holds the correct memory allocation size */
+  assert( p->szMalloc==0
+       || (p->flags==MEM_Undefined
+           && p->szMalloc<=sqlite3DbMallocSize(p->db,p->zMalloc))
+       || p->szMalloc==sqlite3DbMallocSize(p->db,p->zMalloc));
+
+  /* If p holds a string or blob, the Mem.z must point to exactly
+  ** one of the following:
+  **
+  **   (1) Memory in Mem.zMalloc and managed by the Mem object
+  **   (2) Memory to be freed using Mem.xDel
+  **   (3) An ephemeral string or blob
+  **   (4) A static string or blob
+  */
+  if( (p->flags & (MEM_Str|MEM_Blob)) && p->n>0 ){
+    assert(
+      ((p->szMalloc>0 && p->z==p->zMalloc)? 1 : 0) +
+      ((p->flags&MEM_Dyn)!=0 ? 1 : 0) +
+      ((p->flags&MEM_Ephem)!=0 ? 1 : 0) +
+      ((p->flags&MEM_Static)!=0 ? 1 : 0) == 1
+    );
+  }
+  return 1;
+}
+#endif
+
+/*
+** Render a Mem object which is one of MEM_Int, MEM_Real, or MEM_IntReal
+** into a buffer.
+*/
+static void vdbeMemRenderNum(int sz, char *zBuf, Mem *p){
+  StrAccum acc;
+  assert( p->flags & (MEM_Int|MEM_Real|MEM_IntReal) );
+  assert( sz>22 );
+  if( p->flags & MEM_Int ){
+#if GCC_VERSION>=7000000
+    /* Work-around for GCC bug
+    ** https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96270 */
+    i64 x;
+    assert( (p->flags&MEM_Int)*2==sizeof(x) );
+    memcpy(&x, (char*)&p->u, (p->flags&MEM_Int)*2);
+    p->n = sqlite3Int64ToText(x, zBuf);
+#else
+    p->n = sqlite3Int64ToText(p->u.i, zBuf);
+#endif
+  }else{
+    sqlite3StrAccumInit(&acc, 0, zBuf, sz, 0);
+    sqlite3_str_appendf(&acc, "%!.15g",
+         (p->flags & MEM_IntReal)!=0 ? (double)p->u.i : p->u.r);
+    assert( acc.zText==zBuf && acc.mxAlloc<=0 );
+    zBuf[acc.nChar] = 0; /* Fast version of sqlite3StrAccumFinish(&acc) */
+    p->n = acc.nChar;
+  }
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Validity checks on pMem.  pMem holds a string.
+**
+** (1) Check that string value of pMem agrees with its integer or real value.
+** (2) Check that the string is correctly zero terminated
+**
+** A single int or real value always converts to the same strings.  But
+** many different strings can be converted into the same int or real.
+** If a table contains a numeric value and an index is based on the
+** corresponding string value, then it is important that the string be
+** derived from the numeric value, not the other way around, to ensure
+** that the index and table are consistent.  See ticket
+** https://www.sqlite.org/src/info/343634942dd54ab (2018-01-31) for
+** an example.
+**
+** This routine looks at pMem to verify that if it has both a numeric
+** representation and a string representation then the string rep has
+** been derived from the numeric and not the other way around.  It returns
+** true if everything is ok and false if there is a problem.
+**
+** This routine is for use inside of assert() statements only.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemValidStrRep(Mem *p){
+  Mem tmp;
+  char zBuf[100];
+  char *z;
+  int i, j, incr;
+  if( (p->flags & MEM_Str)==0 ) return 1;
+  if( p->db && p->db->mallocFailed ) return 1;
+  if( p->flags & MEM_Term ){
+    /* Insure that the string is properly zero-terminated.  Pay particular
+    ** attention to the case where p->n is odd */
+    if( p->szMalloc>0 && p->z==p->zMalloc ){
+      assert( p->enc==SQLITE_UTF8 || p->szMalloc >= ((p->n+1)&~1)+2 );
+      assert( p->enc!=SQLITE_UTF8 || p->szMalloc >= p->n+1 );
+    }
+    assert( p->z[p->n]==0 );
+    assert( p->enc==SQLITE_UTF8 || p->z[(p->n+1)&~1]==0 );
+    assert( p->enc==SQLITE_UTF8 || p->z[((p->n+1)&~1)+1]==0 );
+  }
+  if( (p->flags & (MEM_Int|MEM_Real|MEM_IntReal))==0 ) return 1;
+  memcpy(&tmp, p, sizeof(tmp));
+  vdbeMemRenderNum(sizeof(zBuf), zBuf, &tmp);
+  z = p->z;
+  i = j = 0;
+  incr = 1;
+  if( p->enc!=SQLITE_UTF8 ){
+    incr = 2;
+    if( p->enc==SQLITE_UTF16BE ) z++;
+  }
+  while( zBuf[j] ){
+    if( zBuf[j++]!=z[i] ) return 0;
+    i += incr;
+  }
+  return 1;
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** If pMem is an object with a valid string representation, this routine
+** ensures the internal encoding for the string representation is
+** 'desiredEnc', one of SQLITE_UTF8, SQLITE_UTF16LE or SQLITE_UTF16BE.
+**
+** If pMem is not a string object, or the encoding of the string
+** representation is already stored using the requested encoding, then this
+** routine is a no-op.
+**
+** SQLITE_OK is returned if the conversion is successful (or not required).
+** SQLITE_NOMEM may be returned if a malloc() fails during conversion
+** between formats.
+*/
+SQLITE_PRIVATE int sqlite3VdbeChangeEncoding(Mem *pMem, int desiredEnc){
+#ifndef SQLITE_OMIT_UTF16
+  int rc;
+#endif
+  assert( pMem!=0 );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( desiredEnc==SQLITE_UTF8 || desiredEnc==SQLITE_UTF16LE
+           || desiredEnc==SQLITE_UTF16BE );
+  if( !(pMem->flags&MEM_Str) ){
+    pMem->enc = desiredEnc;
+    return SQLITE_OK;
+  }
+  if( pMem->enc==desiredEnc ){
+    return SQLITE_OK;
+  }
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+#ifdef SQLITE_OMIT_UTF16
+  return SQLITE_ERROR;
+#else
+
+  /* MemTranslate() may return SQLITE_OK or SQLITE_NOMEM. If NOMEM is returned,
+  ** then the encoding of the value may not have changed.
+  */
+  rc = sqlite3VdbeMemTranslate(pMem, (u8)desiredEnc);
+  assert(rc==SQLITE_OK    || rc==SQLITE_NOMEM);
+  assert(rc==SQLITE_OK    || pMem->enc!=desiredEnc);
+  assert(rc==SQLITE_NOMEM || pMem->enc==desiredEnc);
+  return rc;
+#endif
+}
+
+/*
+** Make sure pMem->z points to a writable allocation of at least n bytes.
+**
+** If the bPreserve argument is true, then copy of the content of
+** pMem->z into the new allocation.  pMem must be either a string or
+** blob if bPreserve is true.  If bPreserve is false, any prior content
+** in pMem->z is discarded.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3VdbeMemGrow(Mem *pMem, int n, int bPreserve){
+  assert( sqlite3VdbeCheckMemInvariants(pMem) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  testcase( pMem->db==0 );
+
+  /* If the bPreserve flag is set to true, then the memory cell must already
+  ** contain a valid string or blob value.  */
+  assert( bPreserve==0 || pMem->flags&(MEM_Blob|MEM_Str) );
+  testcase( bPreserve && pMem->z==0 );
+
+  assert( pMem->szMalloc==0
+       || (pMem->flags==MEM_Undefined
+           && pMem->szMalloc<=sqlite3DbMallocSize(pMem->db,pMem->zMalloc))
+       || pMem->szMalloc==sqlite3DbMallocSize(pMem->db,pMem->zMalloc));
+  if( pMem->szMalloc>0 && bPreserve && pMem->z==pMem->zMalloc ){
+    if( pMem->db ){
+      pMem->z = pMem->zMalloc = sqlite3DbReallocOrFree(pMem->db, pMem->z, n);
+    }else{
+      pMem->zMalloc = sqlite3Realloc(pMem->z, n);
+      if( pMem->zMalloc==0 ) sqlite3_free(pMem->z);
+      pMem->z = pMem->zMalloc;
+    }
+    bPreserve = 0;
+  }else{
+    if( pMem->szMalloc>0 ) sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
+    pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, n);
+  }
+  if( pMem->zMalloc==0 ){
+    sqlite3VdbeMemSetNull(pMem);
+    pMem->z = 0;
+    pMem->szMalloc = 0;
+    return SQLITE_NOMEM_BKPT;
+  }else{
+    pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->zMalloc);
+  }
+
+  if( bPreserve && pMem->z ){
+    assert( pMem->z!=pMem->zMalloc );
+    memcpy(pMem->zMalloc, pMem->z, pMem->n);
+  }
+  if( (pMem->flags&MEM_Dyn)!=0 ){
+    assert( pMem->xDel!=0 && pMem->xDel!=SQLITE_DYNAMIC );
+    pMem->xDel((void *)(pMem->z));
+  }
+
+  pMem->z = pMem->zMalloc;
+  pMem->flags &= ~(MEM_Dyn|MEM_Ephem|MEM_Static);
+  return SQLITE_OK;
+}
+
+/*
+** Change the pMem->zMalloc allocation to be at least szNew bytes.
+** If pMem->zMalloc already meets or exceeds the requested size, this
+** routine is a no-op.
+**
+** Any prior string or blob content in the pMem object may be discarded.
+** The pMem->xDel destructor is called, if it exists.  Though MEM_Str
+** and MEM_Blob values may be discarded, MEM_Int, MEM_Real, MEM_IntReal,
+** and MEM_Null values are preserved.
+**
+** Return SQLITE_OK on success or an error code (probably SQLITE_NOMEM)
+** if unable to complete the resizing.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemClearAndResize(Mem *pMem, int szNew){
+  assert( CORRUPT_DB || szNew>0 );
+  assert( (pMem->flags & MEM_Dyn)==0 || pMem->szMalloc==0 );
+  if( pMem->szMalloc<szNew ){
+    return sqlite3VdbeMemGrow(pMem, szNew, 0);
+  }
+  assert( (pMem->flags & MEM_Dyn)==0 );
+  pMem->z = pMem->zMalloc;
+  pMem->flags &= (MEM_Null|MEM_Int|MEM_Real|MEM_IntReal);
+  return SQLITE_OK;
+}
+
+/*
+** If pMem is already a string, detect if it is a zero-terminated
+** string, or make it into one if possible, and mark it as such.
+**
+** This is an optimization.  Correct operation continues even if
+** this routine is a no-op.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemZeroTerminateIfAble(Mem *pMem){
+  if( (pMem->flags & (MEM_Str|MEM_Term|MEM_Ephem|MEM_Static))!=MEM_Str ){
+    /* pMem must be a string, and it cannot be an ephemeral or static string */
+    return;
+  }
+  if( pMem->enc!=SQLITE_UTF8 ) return;
+  if( NEVER(pMem->z==0) ) return;
+  if( pMem->flags & MEM_Dyn ){
+    if( pMem->xDel==sqlite3_free
+     && sqlite3_msize(pMem->z) >= (u64)(pMem->n+1)
+    ){
+      pMem->z[pMem->n] = 0;
+      pMem->flags |= MEM_Term;
+      return;
+    }
+    if( pMem->xDel==sqlite3RCStrUnref ){
+      /* Blindly assume that all RCStr objects are zero-terminated */
+      pMem->flags |= MEM_Term;
+      return;
+    }
+  }else if( pMem->szMalloc >= pMem->n+1 ){
+    pMem->z[pMem->n] = 0;
+    pMem->flags |= MEM_Term;
+    return;
+  }
+}
+
+/*
+** It is already known that pMem contains an unterminated string.
+** Add the zero terminator.
+**
+** Three bytes of zero are added.  In this way, there is guaranteed
+** to be a double-zero byte at an even byte boundary in order to
+** terminate a UTF16 string, even if the initial size of the buffer
+** is an odd number of bytes.
+*/
+static SQLITE_NOINLINE int vdbeMemAddTerminator(Mem *pMem){
+  if( sqlite3VdbeMemGrow(pMem, pMem->n+3, 1) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  pMem->z[pMem->n] = 0;
+  pMem->z[pMem->n+1] = 0;
+  pMem->z[pMem->n+2] = 0;
+  pMem->flags |= MEM_Term;
+  return SQLITE_OK;
+}
+
+/*
+** Change pMem so that its MEM_Str or MEM_Blob value is stored in
+** MEM.zMalloc, where it can be safely written.
+**
+** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  if( (pMem->flags & (MEM_Str|MEM_Blob))!=0 ){
+    if( ExpandBlob(pMem) ) return SQLITE_NOMEM;
+    if( pMem->szMalloc==0 || pMem->z!=pMem->zMalloc ){
+      int rc = vdbeMemAddTerminator(pMem);
+      if( rc ) return rc;
+    }
+  }
+  pMem->flags &= ~MEM_Ephem;
+#ifdef SQLITE_DEBUG
+  pMem->pScopyFrom = 0;
+#endif
+
+  return SQLITE_OK;
+}
+
+/*
+** If the given Mem* has a zero-filled tail, turn it into an ordinary
+** blob stored in dynamically allocated space.
+*/
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE int sqlite3VdbeMemExpandBlob(Mem *pMem){
+  int nByte;
+  assert( pMem!=0 );
+  assert( pMem->flags & MEM_Zero );
+  assert( (pMem->flags&MEM_Blob)!=0 || MemNullNochng(pMem) );
+  testcase( sqlite3_value_nochange(pMem) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+
+  /* Set nByte to the number of bytes required to store the expanded blob. */
+  nByte = pMem->n + pMem->u.nZero;
+  if( nByte<=0 ){
+    if( (pMem->flags & MEM_Blob)==0 ) return SQLITE_OK;
+    nByte = 1;
+  }
+  if( sqlite3VdbeMemGrow(pMem, nByte, 1) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( pMem->z!=0 );
+  assert( sqlite3DbMallocSize(pMem->db,pMem->z) >= nByte );
+
+  memset(&pMem->z[pMem->n], 0, pMem->u.nZero);
+  pMem->n += pMem->u.nZero;
+  pMem->flags &= ~(MEM_Zero|MEM_Term);
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Make sure the given Mem is \u0000 terminated.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  testcase( (pMem->flags & (MEM_Term|MEM_Str))==(MEM_Term|MEM_Str) );
+  testcase( (pMem->flags & (MEM_Term|MEM_Str))==0 );
+  if( (pMem->flags & (MEM_Term|MEM_Str))!=MEM_Str ){
+    return SQLITE_OK;   /* Nothing to do */
+  }else{
+    return vdbeMemAddTerminator(pMem);
+  }
+}
+
+/*
+** Add MEM_Str to the set of representations for the given Mem.  This
+** routine is only called if pMem is a number of some kind, not a NULL
+** or a BLOB.
+**
+** Existing representations MEM_Int, MEM_Real, or MEM_IntReal are invalidated
+** if bForce is true but are retained if bForce is false.
+**
+** A MEM_Null value will never be passed to this function. This function is
+** used for converting values to text for returning to the user (i.e. via
+** sqlite3_value_text()), or for ensuring that values to be used as btree
+** keys are strings. In the former case a NULL pointer is returned the
+** user and the latter is an internal programming error.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem *pMem, u8 enc, u8 bForce){
+  const int nByte = 32;
+
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !(pMem->flags&MEM_Zero) );
+  assert( !(pMem->flags&(MEM_Str|MEM_Blob)) );
+  assert( pMem->flags&(MEM_Int|MEM_Real|MEM_IntReal) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+
+  if( sqlite3VdbeMemClearAndResize(pMem, nByte) ){
+    pMem->enc = 0;
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  vdbeMemRenderNum(nByte, pMem->z, pMem);
+  assert( pMem->z!=0 );
+  assert( pMem->n==(int)sqlite3Strlen30NN(pMem->z) );
+  pMem->enc = SQLITE_UTF8;
+  pMem->flags |= MEM_Str|MEM_Term;
+  if( bForce ) pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal);
+  sqlite3VdbeChangeEncoding(pMem, enc);
+  return SQLITE_OK;
+}
+
+/*
+** Memory cell pMem contains the context of an aggregate function.
+** This routine calls the finalize method for that function.  The
+** result of the aggregate is stored back into pMem.
+**
+** Return SQLITE_ERROR if the finalizer reports an error.  SQLITE_OK
+** otherwise.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
+  sqlite3_context ctx;
+  Mem t;
+  assert( pFunc!=0 );
+  assert( pMem!=0 );
+  assert( pMem->db!=0 );
+  assert( pFunc->xFinalize!=0 );
+  assert( (pMem->flags & MEM_Null)!=0 || pFunc==pMem->u.pDef );
+  assert( sqlite3_mutex_held(pMem->db->mutex) );
+  memset(&ctx, 0, sizeof(ctx));
+  memset(&t, 0, sizeof(t));
+  t.flags = MEM_Null;
+  t.db = pMem->db;
+  ctx.pOut = &t;
+  ctx.pMem = pMem;
+  ctx.pFunc = pFunc;
+  ctx.enc = ENC(t.db);
+  pFunc->xFinalize(&ctx); /* IMP: R-24505-23230 */
+  assert( (pMem->flags & MEM_Dyn)==0 );
+  if( pMem->szMalloc>0 ) sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
+  memcpy(pMem, &t, sizeof(t));
+  return ctx.isError;
+}
+
+/*
+** Memory cell pAccum contains the context of an aggregate function.
+** This routine calls the xValue method for that function and stores
+** the results in memory cell pMem.
+**
+** SQLITE_ERROR is returned if xValue() reports an error. SQLITE_OK
+** otherwise.
+*/
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE int sqlite3VdbeMemAggValue(Mem *pAccum, Mem *pOut, FuncDef *pFunc){
+  sqlite3_context ctx;
+  assert( pFunc!=0 );
+  assert( pFunc->xValue!=0 );
+  assert( (pAccum->flags & MEM_Null)!=0 || pFunc==pAccum->u.pDef );
+  assert( pAccum->db!=0 );
+  assert( sqlite3_mutex_held(pAccum->db->mutex) );
+  memset(&ctx, 0, sizeof(ctx));
+  sqlite3VdbeMemSetNull(pOut);
+  ctx.pOut = pOut;
+  ctx.pMem = pAccum;
+  ctx.pFunc = pFunc;
+  ctx.enc = ENC(pAccum->db);
+  pFunc->xValue(&ctx);
+  return ctx.isError;
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** If the memory cell contains a value that must be freed by
+** invoking the external callback in Mem.xDel, then this routine
+** will free that value.  It also sets Mem.flags to MEM_Null.
+**
+** This is a helper routine for sqlite3VdbeMemSetNull() and
+** for sqlite3VdbeMemRelease().  Use those other routines as the
+** entry point for releasing Mem resources.
+*/
+static SQLITE_NOINLINE void vdbeMemClearExternAndSetNull(Mem *p){
+  assert( p->db==0 || sqlite3_mutex_held(p->db->mutex) );
+  assert( VdbeMemDynamic(p) );
+  if( p->flags&MEM_Agg ){
+    sqlite3VdbeMemFinalize(p, p->u.pDef);
+    assert( (p->flags & MEM_Agg)==0 );
+    testcase( p->flags & MEM_Dyn );
+  }
+  if( p->flags&MEM_Dyn ){
+    assert( p->xDel!=SQLITE_DYNAMIC && p->xDel!=0 );
+    p->xDel((void *)p->z);
+  }
+  p->flags = MEM_Null;
+}
+
+/*
+** Release memory held by the Mem p, both external memory cleared
+** by p->xDel and memory in p->zMalloc.
+**
+** This is a helper routine invoked by sqlite3VdbeMemRelease() in
+** the unusual case where there really is memory in p that needs
+** to be freed.
+*/
+static SQLITE_NOINLINE void vdbeMemClear(Mem *p){
+  if( VdbeMemDynamic(p) ){
+    vdbeMemClearExternAndSetNull(p);
+  }
+  if( p->szMalloc ){
+    sqlite3DbFreeNN(p->db, p->zMalloc);
+    p->szMalloc = 0;
+  }
+  p->z = 0;
+}
+
+/*
+** Release any memory resources held by the Mem.  Both the memory that is
+** free by Mem.xDel and the Mem.zMalloc allocation are freed.
+**
+** Use this routine prior to clean up prior to abandoning a Mem, or to
+** reset a Mem back to its minimum memory utilization.
+**
+** Use sqlite3VdbeMemSetNull() to release just the Mem.xDel space
+** prior to inserting new content into the Mem.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p){
+  assert( sqlite3VdbeCheckMemInvariants(p) );
+  if( VdbeMemDynamic(p) || p->szMalloc ){
+    vdbeMemClear(p);
+  }
+}
+
+/* Like sqlite3VdbeMemRelease() but faster for cases where we
+** know in advance that the Mem is not MEM_Dyn or MEM_Agg.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemReleaseMalloc(Mem *p){
+  assert( !VdbeMemDynamic(p) );
+  if( p->szMalloc ) vdbeMemClear(p);
+}
+
+/*
+** Return some kind of integer value which is the best we can do
+** at representing the value that *pMem describes as an integer.
+** If pMem is an integer, then the value is exact.  If pMem is
+** a floating-point then the value returned is the integer part.
+** If pMem is a string or blob, then we make an attempt to convert
+** it into an integer and return that.  If pMem represents an
+** an SQL-NULL value, return 0.
+**
+** If pMem represents a string value, its encoding might be changed.
+*/
+static SQLITE_NOINLINE i64 memIntValue(const Mem *pMem){
+  i64 value = 0;
+  sqlite3Atoi64(pMem->z, &value, pMem->n, pMem->enc);
+  return value;
+}
+SQLITE_PRIVATE i64 sqlite3VdbeIntValue(const Mem *pMem){
+  int flags;
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+  flags = pMem->flags;
+  if( flags & (MEM_Int|MEM_IntReal) ){
+    testcase( flags & MEM_IntReal );
+    return pMem->u.i;
+  }else if( flags & MEM_Real ){
+    return sqlite3RealToI64(pMem->u.r);
+  }else if( (flags & (MEM_Str|MEM_Blob))!=0 && pMem->z!=0 ){
+    return memIntValue(pMem);
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Return the best representation of pMem that we can get into a
+** double.  If pMem is already a double or an integer, return its
+** value.  If it is a string or blob, try to convert it to a double.
+** If it is a NULL, return 0.0.
+*/
+static SQLITE_NOINLINE double memRealValue(Mem *pMem){
+  /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+  double val = (double)0;
+  sqlite3AtoF(pMem->z, &val, pMem->n, pMem->enc);
+  return val;
+}
+SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+  if( pMem->flags & MEM_Real ){
+    return pMem->u.r;
+  }else if( pMem->flags & (MEM_Int|MEM_IntReal) ){
+    testcase( pMem->flags & MEM_IntReal );
+    return (double)pMem->u.i;
+  }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
+    return memRealValue(pMem);
+  }else{
+    /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+    return (double)0;
+  }
+}
+
+/*
+** Return 1 if pMem represents true, and return 0 if pMem represents false.
+** Return the value ifNull if pMem is NULL.
+*/
+SQLITE_PRIVATE int sqlite3VdbeBooleanValue(Mem *pMem, int ifNull){
+  testcase( pMem->flags & MEM_IntReal );
+  if( pMem->flags & (MEM_Int|MEM_IntReal) ) return pMem->u.i!=0;
+  if( pMem->flags & MEM_Null ) return ifNull;
+  return sqlite3VdbeRealValue(pMem)!=0.0;
+}
+
+/*
+** The MEM structure is already a MEM_Real or MEM_IntReal. Try to
+** make it a MEM_Int if we can.
+*/
+SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->flags & (MEM_Real|MEM_IntReal) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+  if( pMem->flags & MEM_IntReal ){
+    MemSetTypeFlag(pMem, MEM_Int);
+  }else{
+    i64 ix = sqlite3RealToI64(pMem->u.r);
+
+    /* Only mark the value as an integer if
+    **
+    **    (1) the round-trip conversion real->int->real is a no-op, and
+    **    (2) The integer is neither the largest nor the smallest
+    **        possible integer (ticket #3922)
+    **
+    ** The second and third terms in the following conditional enforces
+    ** the second condition under the assumption that addition overflow causes
+    ** values to wrap around.
+    */
+    if( pMem->u.r==ix && ix>SMALLEST_INT64 && ix<LARGEST_INT64 ){
+      pMem->u.i = ix;
+      MemSetTypeFlag(pMem, MEM_Int);
+    }
+  }
+}
+
+/*
+** Convert pMem to type integer.  Invalidate any prior representations.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+  pMem->u.i = sqlite3VdbeIntValue(pMem);
+  MemSetTypeFlag(pMem, MEM_Int);
+  return SQLITE_OK;
+}
+
+/*
+** Convert pMem so that it is of type MEM_Real.
+** Invalidate any prior representations.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+  pMem->u.r = sqlite3VdbeRealValue(pMem);
+  MemSetTypeFlag(pMem, MEM_Real);
+  return SQLITE_OK;
+}
+
+/* Compare a floating point value to an integer.  Return true if the two
+** values are the same within the precision of the floating point value.
+**
+** This function assumes that i was obtained by assignment from r1.
+**
+** For some versions of GCC on 32-bit machines, if you do the more obvious
+** comparison of "r1==(double)i" you sometimes get an answer of false even
+** though the r1 and (double)i values are bit-for-bit the same.
+*/
+SQLITE_PRIVATE int sqlite3RealSameAsInt(double r1, sqlite3_int64 i){
+  double r2 = (double)i;
+  return r1==0.0
+      || (memcmp(&r1, &r2, sizeof(r1))==0
+          && i >= -2251799813685248LL && i < 2251799813685248LL);
+}
+
+/* Convert a floating point value to its closest integer.  Do so in
+** a way that avoids 'outside the range of representable values' warnings
+** from UBSAN.
+*/
+SQLITE_PRIVATE i64 sqlite3RealToI64(double r){
+  if( r<-9223372036854774784.0 ) return SMALLEST_INT64;
+  if( r>+9223372036854774784.0 ) return LARGEST_INT64;
+  return (i64)r;
+}
+
+/*
+** Convert pMem so that it has type MEM_Real or MEM_Int.
+** Invalidate any prior representations.
+**
+** Every effort is made to force the conversion, even if the input
+** is a string that does not look completely like a number.  Convert
+** as much of the string as we can and ignore the rest.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem *pMem){
+  assert( pMem!=0 );
+  testcase( pMem->flags & MEM_Int );
+  testcase( pMem->flags & MEM_Real );
+  testcase( pMem->flags & MEM_IntReal );
+  testcase( pMem->flags & MEM_Null );
+  if( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))==0 ){
+    int rc;
+    sqlite3_int64 ix;
+    assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
+    assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+    rc = sqlite3AtoF(pMem->z, &pMem->u.r, pMem->n, pMem->enc);
+    if( ((rc==0 || rc==1) && sqlite3Atoi64(pMem->z, &ix, pMem->n, pMem->enc)<=1)
+     || sqlite3RealSameAsInt(pMem->u.r, (ix = sqlite3RealToI64(pMem->u.r)))
+    ){
+      pMem->u.i = ix;
+      MemSetTypeFlag(pMem, MEM_Int);
+    }else{
+      MemSetTypeFlag(pMem, MEM_Real);
+    }
+  }
+  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))!=0 );
+  pMem->flags &= ~(MEM_Str|MEM_Blob|MEM_Zero);
+  return SQLITE_OK;
+}
+
+/*
+** Cast the datatype of the value in pMem according to the affinity
+** "aff".  Casting is different from applying affinity in that a cast
+** is forced.  In other words, the value is converted into the desired
+** affinity even if that results in loss of data.  This routine is
+** used (for example) to implement the SQL "cast()" operator.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemCast(Mem *pMem, u8 aff, u8 encoding){
+  if( pMem->flags & MEM_Null ) return SQLITE_OK;
+  switch( aff ){
+    case SQLITE_AFF_BLOB: {   /* Really a cast to BLOB */
+      if( (pMem->flags & MEM_Blob)==0 ){
+        sqlite3ValueApplyAffinity(pMem, SQLITE_AFF_TEXT, encoding);
+        assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
+        if( pMem->flags & MEM_Str ) MemSetTypeFlag(pMem, MEM_Blob);
+      }else{
+        pMem->flags &= ~(MEM_TypeMask&~MEM_Blob);
+      }
+      break;
+    }
+    case SQLITE_AFF_NUMERIC: {
+      sqlite3VdbeMemNumerify(pMem);
+      break;
+    }
+    case SQLITE_AFF_INTEGER: {
+      sqlite3VdbeMemIntegerify(pMem);
+      break;
+    }
+    case SQLITE_AFF_REAL: {
+      sqlite3VdbeMemRealify(pMem);
+      break;
+    }
+    default: {
+      int rc;
+      assert( aff==SQLITE_AFF_TEXT );
+      assert( MEM_Str==(MEM_Blob>>3) );
+      pMem->flags |= (pMem->flags&MEM_Blob)>>3;
+      sqlite3ValueApplyAffinity(pMem, SQLITE_AFF_TEXT, encoding);
+      assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
+      pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal|MEM_Blob|MEM_Zero);
+      if( encoding!=SQLITE_UTF8 ) pMem->n &= ~1;
+      rc = sqlite3VdbeChangeEncoding(pMem, encoding);
+      if( rc ) return rc;
+      sqlite3VdbeMemZeroTerminateIfAble(pMem);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Initialize bulk memory to be a consistent Mem object.
+**
+** The minimum amount of initialization feasible is performed.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemInit(Mem *pMem, sqlite3 *db, u16 flags){
+  assert( (flags & ~MEM_TypeMask)==0 );
+  pMem->flags = flags;
+  pMem->db = db;
+  pMem->szMalloc = 0;
+}
+
+
+/*
+** Delete any previous value and set the value stored in *pMem to NULL.
+**
+** This routine calls the Mem.xDel destructor to dispose of values that
+** require the destructor.  But it preserves the Mem.zMalloc memory allocation.
+** To free all resources, use sqlite3VdbeMemRelease(), which both calls this
+** routine to invoke the destructor and deallocates Mem.zMalloc.
+**
+** Use this routine to reset the Mem prior to insert a new value.
+**
+** Use sqlite3VdbeMemRelease() to complete erase the Mem prior to abandoning it.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem *pMem){
+  if( VdbeMemDynamic(pMem) ){
+    vdbeMemClearExternAndSetNull(pMem);
+  }else{
+    pMem->flags = MEM_Null;
+  }
+}
+SQLITE_PRIVATE void sqlite3ValueSetNull(sqlite3_value *p){
+  sqlite3VdbeMemSetNull((Mem*)p);
+}
+
+/*
+** Delete any previous value and set the value to be a BLOB of length
+** n containing all zeros.
+*/
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
+  sqlite3VdbeMemRelease(pMem);
+  pMem->flags = MEM_Blob|MEM_Zero;
+  pMem->n = 0;
+  if( n<0 ) n = 0;
+  pMem->u.nZero = n;
+  pMem->enc = SQLITE_UTF8;
+  pMem->z = 0;
+}
+#else
+SQLITE_PRIVATE int sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
+  int nByte = n>0?n:1;
+  if( sqlite3VdbeMemGrow(pMem, nByte, 0) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( pMem->z!=0 );
+  assert( sqlite3DbMallocSize(pMem->db, pMem->z)>=nByte );
+  memset(pMem->z, 0, nByte);
+  pMem->n = n>0?n:0;
+  pMem->flags = MEM_Blob;
+  pMem->enc = SQLITE_UTF8;
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** The pMem is known to contain content that needs to be destroyed prior
+** to a value change.  So invoke the destructor, then set the value to
+** a 64-bit integer.
+*/
+static SQLITE_NOINLINE void vdbeReleaseAndSetInt64(Mem *pMem, i64 val){
+  sqlite3VdbeMemSetNull(pMem);
+  pMem->u.i = val;
+  pMem->flags = MEM_Int;
+}
+
+/*
+** Delete any previous value and set the value stored in *pMem to val,
+** manifest type INTEGER.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
+  if( VdbeMemDynamic(pMem) ){
+    vdbeReleaseAndSetInt64(pMem, val);
+  }else{
+    pMem->u.i = val;
+    pMem->flags = MEM_Int;
+  }
+}
+
+/*
+** Set the iIdx'th entry of array aMem[] to contain integer value val.
+*/
+SQLITE_PRIVATE void sqlite3MemSetArrayInt64(sqlite3_value *aMem, int iIdx, i64 val){
+  sqlite3VdbeMemSetInt64(&aMem[iIdx], val);
+}
+
+/* A no-op destructor */
+SQLITE_PRIVATE void sqlite3NoopDestructor(void *p){ UNUSED_PARAMETER(p); }
+
+/*
+** Set the value stored in *pMem should already be a NULL.
+** Also store a pointer to go with it.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetPointer(
+  Mem *pMem,
+  void *pPtr,
+  const char *zPType,
+  void (*xDestructor)(void*)
+){
+  assert( pMem->flags==MEM_Null );
+  vdbeMemClear(pMem);
+  pMem->u.zPType = zPType ? zPType : "";
+  pMem->z = pPtr;
+  pMem->flags = MEM_Null|MEM_Dyn|MEM_Subtype|MEM_Term;
+  pMem->eSubtype = 'p';
+  pMem->xDel = xDestructor ? xDestructor : sqlite3NoopDestructor;
+}
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Delete any previous value and set the value stored in *pMem to val,
+** manifest type REAL.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
+  sqlite3VdbeMemSetNull(pMem);
+  if( !sqlite3IsNaN(val) ){
+    pMem->u.r = val;
+    pMem->flags = MEM_Real;
+  }
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Return true if the Mem holds a RowSet object.  This routine is intended
+** for use inside of assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemIsRowSet(const Mem *pMem){
+  return (pMem->flags&(MEM_Blob|MEM_Dyn))==(MEM_Blob|MEM_Dyn)
+         && pMem->xDel==sqlite3RowSetDelete;
+}
+#endif
+
+/*
+** Delete any previous value and set the value of pMem to be an
+** empty boolean index.
+**
+** Return SQLITE_OK on success and SQLITE_NOMEM if a memory allocation
+** error occurs.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemSetRowSet(Mem *pMem){
+  sqlite3 *db = pMem->db;
+  RowSet *p;
+  assert( db!=0 );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  sqlite3VdbeMemRelease(pMem);
+  p = sqlite3RowSetInit(db);
+  if( p==0 ) return SQLITE_NOMEM;
+  pMem->z = (char*)p;
+  pMem->flags = MEM_Blob|MEM_Dyn;
+  pMem->xDel = sqlite3RowSetDelete;
+  return SQLITE_OK;
+}
+
+/*
+** Return true if the Mem object contains a TEXT or BLOB that is
+** too large - whose size exceeds SQLITE_MAX_LENGTH.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem *p){
+  assert( p->db!=0 );
+  if( p->flags & (MEM_Str|MEM_Blob) ){
+    int n = p->n;
+    if( p->flags & MEM_Zero ){
+      n += p->u.nZero;
+    }
+    return n>p->db->aLimit[SQLITE_LIMIT_LENGTH];
+  }
+  return 0;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** This routine prepares a memory cell for modification by breaking
+** its link to a shallow copy and by marking any current shallow
+** copies of this cell as invalid.
+**
+** This is used for testing and debugging only - to help ensure that shallow
+** copies (created by OP_SCopy) are not misused.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
+  int i;
+  Mem *pX;
+  if( pMem->bScopy ){
+    for(i=1, pX=pVdbe->aMem+1; i<pVdbe->nMem; i++, pX++){
+      if( pX->pScopyFrom==pMem ){
+        u16 mFlags;
+        if( pVdbe->db->flags & SQLITE_VdbeTrace ){
+          sqlite3DebugPrintf("Invalidate R[%d] due to change in R[%d]\n",
+            (int)(pX - pVdbe->aMem), (int)(pMem - pVdbe->aMem));
+        }
+        /* If pX is marked as a shallow copy of pMem, then try to verify that
+        ** no significant changes have been made to pX since the OP_SCopy.
+        ** A significant change would indicated a missed call to this
+        ** function for pX.  Minor changes, such as adding or removing a
+        ** dual type, are allowed, as long as the underlying value is the
+        ** same. */
+        mFlags = pMem->flags & pX->flags & pX->mScopyFlags;
+        assert( (mFlags&(MEM_Int|MEM_IntReal))==0 || pMem->u.i==pX->u.i );
+
+        /* pMem is the register that is changing.  But also mark pX as
+        ** undefined so that we can quickly detect the shallow-copy error */
+        pX->flags = MEM_Undefined;
+        pX->pScopyFrom = 0;
+      }
+    }
+    pMem->bScopy = 0;
+  }
+  pMem->pScopyFrom = 0;
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** Make an shallow copy of pFrom into pTo.  Prior contents of
+** pTo are freed.  The pFrom->z field is not duplicated.  If
+** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
+** and flags gets srcType (either MEM_Ephem or MEM_Static).
+*/
+static SQLITE_NOINLINE void vdbeClrCopy(Mem *pTo, const Mem *pFrom, int eType){
+  vdbeMemClearExternAndSetNull(pTo);
+  assert( !VdbeMemDynamic(pTo) );
+  sqlite3VdbeMemShallowCopy(pTo, pFrom, eType);
+}
+SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
+  assert( !sqlite3VdbeMemIsRowSet(pFrom) );
+  assert( pTo->db==pFrom->db );
+  if( VdbeMemDynamic(pTo) ){ vdbeClrCopy(pTo,pFrom,srcType); return; }
+  memcpy(pTo, pFrom, MEMCELLSIZE);
+  if( (pFrom->flags&MEM_Static)==0 ){
+    pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
+    assert( srcType==MEM_Ephem || srcType==MEM_Static );
+    pTo->flags |= srcType;
+  }
+}
+
+/*
+** Make a full copy of pFrom into pTo.  Prior contents of pTo are
+** freed before the copy is made.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
+  int rc = SQLITE_OK;
+
+  assert( !sqlite3VdbeMemIsRowSet(pFrom) );
+  if( VdbeMemDynamic(pTo) ) vdbeMemClearExternAndSetNull(pTo);
+  memcpy(pTo, pFrom, MEMCELLSIZE);
+  pTo->flags &= ~MEM_Dyn;
+  if( pTo->flags&(MEM_Str|MEM_Blob) ){
+    if( 0==(pFrom->flags&MEM_Static) ){
+      pTo->flags |= MEM_Ephem;
+      rc = sqlite3VdbeMemMakeWriteable(pTo);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Transfer the contents of pFrom to pTo. Any existing value in pTo is
+** freed. If pFrom contains ephemeral data, a copy is made.
+**
+** pFrom contains an SQL NULL when this routine returns.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem *pTo, Mem *pFrom){
+  assert( pFrom->db==0 || sqlite3_mutex_held(pFrom->db->mutex) );
+  assert( pTo->db==0 || sqlite3_mutex_held(pTo->db->mutex) );
+  assert( pFrom->db==0 || pTo->db==0 || pFrom->db==pTo->db );
+
+  sqlite3VdbeMemRelease(pTo);
+  memcpy(pTo, pFrom, sizeof(Mem));
+  pFrom->flags = MEM_Null;
+  pFrom->szMalloc = 0;
+}
+
+/*
+** Change the value of a Mem to be a string or a BLOB.
+**
+** The memory management strategy depends on the value of the xDel
+** parameter. If the value passed is SQLITE_TRANSIENT, then the
+** string is copied into a (possibly existing) buffer managed by the
+** Mem structure. Otherwise, any existing buffer is freed and the
+** pointer copied.
+**
+** If the string is too large (if it exceeds the SQLITE_LIMIT_LENGTH
+** size limit) then no memory allocation occurs.  If the string can be
+** stored without allocating memory, then it is.  If a memory allocation
+** is required to store the string, then value of pMem is unchanged.  In
+** either case, SQLITE_TOOBIG is returned.
+**
+** The "enc" parameter is the text encoding for the string, or zero
+** to store a blob.
+**
+** If n is negative, then the string consists of all bytes up to but
+** excluding the first zero character.  The n parameter must be
+** non-negative for blobs.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemSetStr(
+  Mem *pMem,          /* Memory cell to set to string value */
+  const char *z,      /* String pointer */
+  i64 n,              /* Bytes in string, or negative */
+  u8 enc,             /* Encoding of z.  0 for BLOBs */
+  void (*xDel)(void*) /* Destructor function */
+){
+  i64 nByte = n;      /* New value for pMem->n */
+  int iLimit;         /* Maximum allowed string or blob size */
+  u16 flags;          /* New value for pMem->flags */
+
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( enc!=0 || n>=0 );
+
+  /* If z is a NULL pointer, set pMem to contain an SQL NULL. */
+  if( !z ){
+    sqlite3VdbeMemSetNull(pMem);
+    return SQLITE_OK;
+  }
+
+  if( pMem->db ){
+    iLimit = pMem->db->aLimit[SQLITE_LIMIT_LENGTH];
+  }else{
+    iLimit = SQLITE_MAX_LENGTH;
+  }
+  if( nByte<0 ){
+    assert( enc!=0 );
+    if( enc==SQLITE_UTF8 ){
+      nByte = strlen(z);
+    }else{
+      for(nByte=0; nByte<=iLimit && (z[nByte] | z[nByte+1]); nByte+=2){}
+    }
+    flags= MEM_Str|MEM_Term;
+  }else if( enc==0 ){
+    flags = MEM_Blob;
+    enc = SQLITE_UTF8;
+  }else{
+    flags = MEM_Str;
+  }
+  if( nByte>iLimit ){
+    if( xDel && xDel!=SQLITE_TRANSIENT ){
+      if( xDel==SQLITE_DYNAMIC ){
+        sqlite3DbFree(pMem->db, (void*)z);
+      }else{
+        xDel((void*)z);
+      }
+    }
+    sqlite3VdbeMemSetNull(pMem);
+    return sqlite3ErrorToParser(pMem->db, SQLITE_TOOBIG);
+  }
+
+  /* The following block sets the new values of Mem.z and Mem.xDel. It
+  ** also sets a flag in local variable "flags" to indicate the memory
+  ** management (one of MEM_Dyn or MEM_Static).
+  */
+  if( xDel==SQLITE_TRANSIENT ){
+    i64 nAlloc = nByte;
+    if( flags&MEM_Term ){
+      nAlloc += (enc==SQLITE_UTF8?1:2);
+    }
+    testcase( nAlloc==0 );
+    testcase( nAlloc==31 );
+    testcase( nAlloc==32 );
+    if( sqlite3VdbeMemClearAndResize(pMem, (int)MAX(nAlloc,32)) ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    memcpy(pMem->z, z, nAlloc);
+  }else{
+    sqlite3VdbeMemRelease(pMem);
+    pMem->z = (char *)z;
+    if( xDel==SQLITE_DYNAMIC ){
+      pMem->zMalloc = pMem->z;
+      pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->zMalloc);
+    }else{
+      pMem->xDel = xDel;
+      flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
+    }
+  }
+
+  pMem->n = (int)(nByte & 0x7fffffff);
+  pMem->flags = flags;
+  pMem->enc = enc;
+
+#ifndef SQLITE_OMIT_UTF16
+  if( enc>SQLITE_UTF8 && sqlite3VdbeMemHandleBom(pMem) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+#endif
+
+
+  return SQLITE_OK;
+}
+
+/*
+** Move data out of a btree key or data field and into a Mem structure.
+** The data is payload from the entry that pCur is currently pointing
+** to.  offset and amt determine what portion of the data or key to retrieve.
+** The result is written into the pMem element.
+**
+** The pMem object must have been initialized.  This routine will use
+** pMem->zMalloc to hold the content from the btree, if possible.  New
+** pMem->zMalloc space will be allocated if necessary.  The calling routine
+** is responsible for making sure that the pMem object is eventually
+** destroyed.
+**
+** If this routine fails for any reason (malloc returns NULL or unable
+** to read from the disk) then the pMem is left in an inconsistent state.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(
+  BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
+  u32 offset,       /* Offset from the start of data to return bytes from. */
+  u32 amt,          /* Number of bytes to return. */
+  Mem *pMem         /* OUT: Return data in this Mem structure. */
+){
+  int rc;
+  pMem->flags = MEM_Null;
+  if( sqlite3BtreeMaxRecordSize(pCur)<offset+amt ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( SQLITE_OK==(rc = sqlite3VdbeMemClearAndResize(pMem, amt+1)) ){
+    rc = sqlite3BtreePayload(pCur, offset, amt, pMem->z);
+    if( rc==SQLITE_OK ){
+      pMem->z[amt] = 0;   /* Overrun area used when reading malformed records */
+      pMem->flags = MEM_Blob;
+      pMem->n = (int)amt;
+    }else{
+      sqlite3VdbeMemRelease(pMem);
+    }
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtreeZeroOffset(
+  BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
+  u32 amt,          /* Number of bytes to return. */
+  Mem *pMem         /* OUT: Return data in this Mem structure. */
+){
+  u32 available = 0;  /* Number of bytes available on the local btree page */
+  int rc = SQLITE_OK; /* Return code */
+
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+  assert( !VdbeMemDynamic(pMem) );
+
+  /* Note: the calls to BtreeKeyFetch() and DataFetch() below assert()
+  ** that both the BtShared and database handle mutexes are held. */
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  pMem->z = (char *)sqlite3BtreePayloadFetch(pCur, &available);
+  assert( pMem->z!=0 );
+
+  if( amt<=available ){
+    pMem->flags = MEM_Blob|MEM_Ephem;
+    pMem->n = (int)amt;
+  }else{
+    rc = sqlite3VdbeMemFromBtree(pCur, 0, amt, pMem);
+  }
+
+  return rc;
+}
+
+/*
+** The pVal argument is known to be a value other than NULL.
+** Convert it into a string with encoding enc and return a pointer
+** to a zero-terminated version of that string.
+*/
+static SQLITE_NOINLINE const void *valueToText(sqlite3_value* pVal, u8 enc){
+  assert( pVal!=0 );
+  assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
+  assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
+  assert( !sqlite3VdbeMemIsRowSet(pVal) );
+  assert( (pVal->flags & (MEM_Null))==0 );
+  if( pVal->flags & (MEM_Blob|MEM_Str) ){
+    if( ExpandBlob(pVal) ) return 0;
+    pVal->flags |= MEM_Str;
+    if( pVal->enc != (enc & ~SQLITE_UTF16_ALIGNED) ){
+      sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
+    }
+    if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
+      assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
+      if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
+        return 0;
+      }
+    }
+    sqlite3VdbeMemNulTerminate(pVal); /* IMP: R-31275-44060 */
+  }else{
+    sqlite3VdbeMemStringify(pVal, enc, 0);
+    assert( 0==(1&SQLITE_PTR_TO_INT(pVal->z)) );
+  }
+  assert(pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) || pVal->db==0
+              || pVal->db->mallocFailed );
+  if( pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) ){
+    assert( sqlite3VdbeMemValidStrRep(pVal) );
+    return pVal->z;
+  }else{
+    return 0;
+  }
+}
+
+/* This function is only available internally, it is not part of the
+** external API. It works in a similar way to sqlite3_value_text(),
+** except the data returned is in the encoding specified by the second
+** parameter, which must be one of SQLITE_UTF16BE, SQLITE_UTF16LE or
+** SQLITE_UTF8.
+**
+** (2006-02-16:)  The enc value can be or-ed with SQLITE_UTF16_ALIGNED.
+** If that is the case, then the result must be aligned on an even byte
+** boundary.
+*/
+SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
+  if( !pVal ) return 0;
+  assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
+  assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
+  assert( !sqlite3VdbeMemIsRowSet(pVal) );
+  if( (pVal->flags&(MEM_Str|MEM_Term))==(MEM_Str|MEM_Term) && pVal->enc==enc ){
+    assert( sqlite3VdbeMemValidStrRep(pVal) );
+    return pVal->z;
+  }
+  if( pVal->flags&MEM_Null ){
+    return 0;
+  }
+  return valueToText(pVal, enc);
+}
+
+/* Return true if sqlit3_value object pVal is a string or blob value
+** that uses the destructor specified in the second argument.
+**
+** TODO:  Maybe someday promote this interface into a published API so
+** that third-party extensions can get access to it?
+*/
+SQLITE_PRIVATE int sqlite3ValueIsOfClass(const sqlite3_value *pVal, void(*xFree)(void*)){
+  if( ALWAYS(pVal!=0)
+   && ALWAYS((pVal->flags & (MEM_Str|MEM_Blob))!=0)
+   && (pVal->flags & MEM_Dyn)!=0
+   && pVal->xDel==xFree
+  ){
+    return 1;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Create a new sqlite3_value object.
+*/
+SQLITE_PRIVATE sqlite3_value *sqlite3ValueNew(sqlite3 *db){
+  Mem *p = sqlite3DbMallocZero(db, sizeof(*p));
+  if( p ){
+    p->flags = MEM_Null;
+    p->db = db;
+  }
+  return p;
+}
+
+/*
+** Context object passed by sqlite3Stat4ProbeSetValue() through to
+** valueNew(). See comments above valueNew() for details.
+*/
+struct ValueNewStat4Ctx {
+  Parse *pParse;
+  Index *pIdx;
+  UnpackedRecord **ppRec;
+  int iVal;
+};
+
+/*
+** Allocate and return a pointer to a new sqlite3_value object. If
+** the second argument to this function is NULL, the object is allocated
+** by calling sqlite3ValueNew().
+**
+** Otherwise, if the second argument is non-zero, then this function is
+** being called indirectly by sqlite3Stat4ProbeSetValue(). If it has not
+** already been allocated, allocate the UnpackedRecord structure that
+** that function will return to its caller here. Then return a pointer to
+** an sqlite3_value within the UnpackedRecord.a[] array.
+*/
+static sqlite3_value *valueNew(sqlite3 *db, struct ValueNewStat4Ctx *p){
+#ifdef SQLITE_ENABLE_STAT4
+  if( p ){
+    UnpackedRecord *pRec = p->ppRec[0];
+
+    if( pRec==0 ){
+      Index *pIdx = p->pIdx;      /* Index being probed */
+      int nByte;                  /* Bytes of space to allocate */
+      int i;                      /* Counter variable */
+      int nCol = pIdx->nColumn;   /* Number of index columns including rowid */
+
+      nByte = sizeof(Mem) * nCol + ROUND8(sizeof(UnpackedRecord));
+      pRec = (UnpackedRecord*)sqlite3DbMallocZero(db, nByte);
+      if( pRec ){
+        pRec->pKeyInfo = sqlite3KeyInfoOfIndex(p->pParse, pIdx);
+        if( pRec->pKeyInfo ){
+          assert( pRec->pKeyInfo->nAllField==nCol );
+          assert( pRec->pKeyInfo->enc==ENC(db) );
+          pRec->aMem = (Mem *)((u8*)pRec + ROUND8(sizeof(UnpackedRecord)));
+          for(i=0; i<nCol; i++){
+            pRec->aMem[i].flags = MEM_Null;
+            pRec->aMem[i].db = db;
+          }
+        }else{
+          sqlite3DbFreeNN(db, pRec);
+          pRec = 0;
+        }
+      }
+      if( pRec==0 ) return 0;
+      p->ppRec[0] = pRec;
+    }
+
+    pRec->nField = p->iVal+1;
+    sqlite3VdbeMemSetNull(&pRec->aMem[p->iVal]);
+    return &pRec->aMem[p->iVal];
+  }
+#else
+  UNUSED_PARAMETER(p);
+#endif /* defined(SQLITE_ENABLE_STAT4) */
+  return sqlite3ValueNew(db);
+}
+
+/*
+** The expression object indicated by the second argument is guaranteed
+** to be a scalar SQL function. If
+**
+**   * all function arguments are SQL literals,
+**   * one of the SQLITE_FUNC_CONSTANT or _SLOCHNG function flags is set, and
+**   * the SQLITE_FUNC_NEEDCOLL function flag is not set,
+**
+** then this routine attempts to invoke the SQL function. Assuming no
+** error occurs, output parameter (*ppVal) is set to point to a value
+** object containing the result before returning SQLITE_OK.
+**
+** Affinity aff is applied to the result of the function before returning.
+** If the result is a text value, the sqlite3_value object uses encoding
+** enc.
+**
+** If the conditions above are not met, this function returns SQLITE_OK
+** and sets (*ppVal) to NULL. Or, if an error occurs, (*ppVal) is set to
+** NULL and an SQLite error code returned.
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static int valueFromFunction(
+  sqlite3 *db,                    /* The database connection */
+  const Expr *p,                  /* The expression to evaluate */
+  u8 enc,                         /* Encoding to use */
+  u8 aff,                         /* Affinity to use */
+  sqlite3_value **ppVal,          /* Write the new value here */
+  struct ValueNewStat4Ctx *pCtx   /* Second argument for valueNew() */
+){
+  sqlite3_context ctx;            /* Context object for function invocation */
+  sqlite3_value **apVal = 0;      /* Function arguments */
+  int nVal = 0;                   /* Size of apVal[] array */
+  FuncDef *pFunc = 0;             /* Function definition */
+  sqlite3_value *pVal = 0;        /* New value */
+  int rc = SQLITE_OK;             /* Return code */
+  ExprList *pList = 0;            /* Function arguments */
+  int i;                          /* Iterator variable */
+
+  assert( pCtx!=0 );
+  assert( (p->flags & EP_TokenOnly)==0 );
+  assert( ExprUseXList(p) );
+  pList = p->x.pList;
+  if( pList ) nVal = pList->nExpr;
+  assert( !ExprHasProperty(p, EP_IntValue) );
+  pFunc = sqlite3FindFunction(db, p->u.zToken, nVal, enc, 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+  if( pFunc==0 ) return SQLITE_OK;
+#endif
+  assert( pFunc );
+  if( (pFunc->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG))==0
+   || (pFunc->funcFlags & (SQLITE_FUNC_NEEDCOLL|SQLITE_FUNC_RUNONLY))!=0
+  ){
+    return SQLITE_OK;
+  }
+
+  if( pList ){
+    apVal = (sqlite3_value**)sqlite3DbMallocZero(db, sizeof(apVal[0]) * nVal);
+    if( apVal==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto value_from_function_out;
+    }
+    for(i=0; i<nVal; i++){
+      rc = sqlite3Stat4ValueFromExpr(pCtx->pParse, pList->a[i].pExpr, aff,
+                                     &apVal[i]);
+      if( apVal[i]==0 || rc!=SQLITE_OK ) goto value_from_function_out;
+    }
+  }
+
+  pVal = valueNew(db, pCtx);
+  if( pVal==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto value_from_function_out;
+  }
+
+  memset(&ctx, 0, sizeof(ctx));
+  ctx.pOut = pVal;
+  ctx.pFunc = pFunc;
+  ctx.enc = ENC(db);
+  pFunc->xSFunc(&ctx, nVal, apVal);
+  if( ctx.isError ){
+    rc = ctx.isError;
+    sqlite3ErrorMsg(pCtx->pParse, "%s", sqlite3_value_text(pVal));
+  }else{
+    sqlite3ValueApplyAffinity(pVal, aff, SQLITE_UTF8);
+    assert( rc==SQLITE_OK );
+    rc = sqlite3VdbeChangeEncoding(pVal, enc);
+    if( NEVER(rc==SQLITE_OK && sqlite3VdbeMemTooBig(pVal)) ){
+      rc = SQLITE_TOOBIG;
+      pCtx->pParse->nErr++;
+    }
+  }
+
+ value_from_function_out:
+  if( rc!=SQLITE_OK ){
+    pVal = 0;
+    pCtx->pParse->rc = rc;
+  }
+  if( apVal ){
+    for(i=0; i<nVal; i++){
+      sqlite3ValueFree(apVal[i]);
+    }
+    sqlite3DbFreeNN(db, apVal);
+  }
+
+  *ppVal = pVal;
+  return rc;
+}
+#else
+# define valueFromFunction(a,b,c,d,e,f) SQLITE_OK
+#endif /* defined(SQLITE_ENABLE_STAT4) */
+
+/*
+** Extract a value from the supplied expression in the manner described
+** above sqlite3ValueFromExpr(). Allocate the sqlite3_value object
+** using valueNew().
+**
+** If pCtx is NULL and an error occurs after the sqlite3_value object
+** has been allocated, it is freed before returning. Or, if pCtx is not
+** NULL, it is assumed that the caller will free any allocated object
+** in all cases.
+*/
+static int valueFromExpr(
+  sqlite3 *db,                    /* The database connection */
+  const Expr *pExpr,              /* The expression to evaluate */
+  u8 enc,                         /* Encoding to use */
+  u8 affinity,                    /* Affinity to use */
+  sqlite3_value **ppVal,          /* Write the new value here */
+  struct ValueNewStat4Ctx *pCtx   /* Second argument for valueNew() */
+){
+  int op;
+  char *zVal = 0;
+  sqlite3_value *pVal = 0;
+  int negInt = 1;
+  const char *zNeg = "";
+  int rc = SQLITE_OK;
+
+  assert( pExpr!=0 );
+  while( (op = pExpr->op)==TK_UPLUS || op==TK_SPAN ) pExpr = pExpr->pLeft;
+  if( op==TK_REGISTER ) op = pExpr->op2;
+
+  /* Compressed expressions only appear when parsing the DEFAULT clause
+  ** on a table column definition, and hence only when pCtx==0.  This
+  ** check ensures that an EP_TokenOnly expression is never passed down
+  ** into valueFromFunction(). */
+  assert( (pExpr->flags & EP_TokenOnly)==0 || pCtx==0 );
+
+  if( op==TK_CAST ){
+    u8 aff;
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    aff = sqlite3AffinityType(pExpr->u.zToken,0);
+    rc = valueFromExpr(db, pExpr->pLeft, enc, aff, ppVal, pCtx);
+    testcase( rc!=SQLITE_OK );
+    if( *ppVal ){
+#ifdef SQLITE_ENABLE_STAT4
+      rc = ExpandBlob(*ppVal);
+#else
+      /* zero-blobs only come from functions, not literal values.  And
+      ** functions are only processed under STAT4 */
+      assert( (ppVal[0][0].flags & MEM_Zero)==0 );
+#endif
+      sqlite3VdbeMemCast(*ppVal, aff, enc);
+      sqlite3ValueApplyAffinity(*ppVal, affinity, enc);
+    }
+    return rc;
+  }
+
+  /* Handle negative integers in a single step.  This is needed in the
+  ** case when the value is -9223372036854775808. Except - do not do this
+  ** for hexadecimal literals.  */
+  if( op==TK_UMINUS ){
+    Expr *pLeft = pExpr->pLeft;
+    if( (pLeft->op==TK_INTEGER || pLeft->op==TK_FLOAT) ){
+      if( ExprHasProperty(pLeft, EP_IntValue)
+       || pLeft->u.zToken[0]!='0' || (pLeft->u.zToken[1] & ~0x20)!='X'
+      ){
+        pExpr = pLeft;
+        op = pExpr->op;
+        negInt = -1;
+        zNeg = "-";
+      }
+    }
+  }
+
+  if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
+    pVal = valueNew(db, pCtx);
+    if( pVal==0 ) goto no_mem;
+    if( ExprHasProperty(pExpr, EP_IntValue) ){
+      sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue*negInt);
+    }else{
+      i64 iVal;
+      if( op==TK_INTEGER && 0==sqlite3DecOrHexToI64(pExpr->u.zToken, &iVal) ){
+        sqlite3VdbeMemSetInt64(pVal, iVal*negInt);
+      }else{
+        zVal = sqlite3MPrintf(db, "%s%s", zNeg, pExpr->u.zToken);
+        if( zVal==0 ) goto no_mem;
+        sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
+      }
+    }
+    if( affinity==SQLITE_AFF_BLOB ){
+      if( op==TK_FLOAT ){
+        assert( pVal && pVal->z && pVal->flags==(MEM_Str|MEM_Term) );
+        sqlite3AtoF(pVal->z, &pVal->u.r, pVal->n, SQLITE_UTF8);
+        pVal->flags = MEM_Real;
+      }else if( op==TK_INTEGER ){
+        /* This case is required by -9223372036854775808 and other strings
+        ** that look like integers but cannot be handled by the
+        ** sqlite3DecOrHexToI64() call above.  */
+        sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
+      }
+    }else{
+      sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
+    }
+    assert( (pVal->flags & MEM_IntReal)==0 );
+    if( pVal->flags & (MEM_Int|MEM_IntReal|MEM_Real) ){
+      testcase( pVal->flags & MEM_Int );
+      testcase( pVal->flags & MEM_Real );
+      pVal->flags &= ~MEM_Str;
+    }
+    if( enc!=SQLITE_UTF8 ){
+      rc = sqlite3VdbeChangeEncoding(pVal, enc);
+    }
+  }else if( op==TK_UMINUS ) {
+    /* This branch happens for multiple negative signs.  Ex: -(-5) */
+    if( SQLITE_OK==valueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal,pCtx)
+     && pVal!=0
+    ){
+      sqlite3VdbeMemNumerify(pVal);
+      if( pVal->flags & MEM_Real ){
+        pVal->u.r = -pVal->u.r;
+      }else if( pVal->u.i==SMALLEST_INT64 ){
+#ifndef SQLITE_OMIT_FLOATING_POINT
+        pVal->u.r = -(double)SMALLEST_INT64;
+#else
+        pVal->u.r = LARGEST_INT64;
+#endif
+        MemSetTypeFlag(pVal, MEM_Real);
+      }else{
+        pVal->u.i = -pVal->u.i;
+      }
+      sqlite3ValueApplyAffinity(pVal, affinity, enc);
+    }
+  }else if( op==TK_NULL ){
+    pVal = valueNew(db, pCtx);
+    if( pVal==0 ) goto no_mem;
+    sqlite3VdbeMemSetNull(pVal);
+  }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+  else if( op==TK_BLOB ){
+    int nVal;
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
+    assert( pExpr->u.zToken[1]=='\'' );
+    pVal = valueNew(db, pCtx);
+    if( !pVal ) goto no_mem;
+    zVal = &pExpr->u.zToken[2];
+    nVal = sqlite3Strlen30(zVal)-1;
+    assert( zVal[nVal]=='\'' );
+    sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
+                         0, SQLITE_DYNAMIC);
+  }
+#endif
+#ifdef SQLITE_ENABLE_STAT4
+  else if( op==TK_FUNCTION && pCtx!=0 ){
+    rc = valueFromFunction(db, pExpr, enc, affinity, &pVal, pCtx);
+  }
+#endif
+  else if( op==TK_TRUEFALSE ){
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    pVal = valueNew(db, pCtx);
+    if( pVal ){
+      pVal->flags = MEM_Int;
+      pVal->u.i = pExpr->u.zToken[4]==0;
+      sqlite3ValueApplyAffinity(pVal, affinity, enc);
+    }
+  }
+
+  *ppVal = pVal;
+  return rc;
+
+no_mem:
+#ifdef SQLITE_ENABLE_STAT4
+  if( pCtx==0 || NEVER(pCtx->pParse->nErr==0) )
+#endif
+    sqlite3OomFault(db);
+  sqlite3DbFree(db, zVal);
+  assert( *ppVal==0 );
+#ifdef SQLITE_ENABLE_STAT4
+  if( pCtx==0 ) sqlite3ValueFree(pVal);
+#else
+  assert( pCtx==0 ); sqlite3ValueFree(pVal);
+#endif
+  return SQLITE_NOMEM_BKPT;
+}
+
+/*
+** Create a new sqlite3_value object, containing the value of pExpr.
+**
+** This only works for very simple expressions that consist of one constant
+** token (i.e. "5", "5.1", "'a string'"). If the expression can
+** be converted directly into a value, then the value is allocated and
+** a pointer written to *ppVal. The caller is responsible for deallocating
+** the value by passing it to sqlite3ValueFree() later on. If the expression
+** cannot be converted to a value, then *ppVal is set to NULL.
+*/
+SQLITE_PRIVATE int sqlite3ValueFromExpr(
+  sqlite3 *db,              /* The database connection */
+  const Expr *pExpr,        /* The expression to evaluate */
+  u8 enc,                   /* Encoding to use */
+  u8 affinity,              /* Affinity to use */
+  sqlite3_value **ppVal     /* Write the new value here */
+){
+  return pExpr ? valueFromExpr(db, pExpr, enc, affinity, ppVal, 0) : 0;
+}
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Attempt to extract a value from pExpr and use it to construct *ppVal.
+**
+** If pAlloc is not NULL, then an UnpackedRecord object is created for
+** pAlloc if one does not exist and the new value is added to the
+** UnpackedRecord object.
+**
+** A value is extracted in the following cases:
+**
+**  * (pExpr==0). In this case the value is assumed to be an SQL NULL,
+**
+**  * The expression is a bound variable, and this is a reprepare, or
+**
+**  * The expression is a literal value.
+**
+** On success, *ppVal is made to point to the extracted value.  The caller
+** is responsible for ensuring that the value is eventually freed.
+*/
+static int stat4ValueFromExpr(
+  Parse *pParse,                  /* Parse context */
+  Expr *pExpr,                    /* The expression to extract a value from */
+  u8 affinity,                    /* Affinity to use */
+  struct ValueNewStat4Ctx *pAlloc,/* How to allocate space.  Or NULL */
+  sqlite3_value **ppVal           /* OUT: New value object (or NULL) */
+){
+  int rc = SQLITE_OK;
+  sqlite3_value *pVal = 0;
+  sqlite3 *db = pParse->db;
+
+  /* Skip over any TK_COLLATE nodes */
+  pExpr = sqlite3ExprSkipCollate(pExpr);
+
+  assert( pExpr==0 || pExpr->op!=TK_REGISTER || pExpr->op2!=TK_VARIABLE );
+  if( !pExpr ){
+    pVal = valueNew(db, pAlloc);
+    if( pVal ){
+      sqlite3VdbeMemSetNull((Mem*)pVal);
+    }
+  }else if( pExpr->op==TK_VARIABLE && (db->flags & SQLITE_EnableQPSG)==0 ){
+    Vdbe *v;
+    int iBindVar = pExpr->iColumn;
+    sqlite3VdbeSetVarmask(pParse->pVdbe, iBindVar);
+    if( (v = pParse->pReprepare)!=0 ){
+      pVal = valueNew(db, pAlloc);
+      if( pVal ){
+        rc = sqlite3VdbeMemCopy((Mem*)pVal, &v->aVar[iBindVar-1]);
+        sqlite3ValueApplyAffinity(pVal, affinity, ENC(db));
+        pVal->db = pParse->db;
+      }
+    }
+  }else{
+    rc = valueFromExpr(db, pExpr, ENC(db), affinity, &pVal, pAlloc);
+  }
+
+  assert( pVal==0 || pVal->db==db );
+  *ppVal = pVal;
+  return rc;
+}
+
+/*
+** This function is used to allocate and populate UnpackedRecord
+** structures intended to be compared against sample index keys stored
+** in the sqlite_stat4 table.
+**
+** A single call to this function populates zero or more fields of the
+** record starting with field iVal (fields are numbered from left to
+** right starting with 0). A single field is populated if:
+**
+**  * (pExpr==0). In this case the value is assumed to be an SQL NULL,
+**
+**  * The expression is a bound variable, and this is a reprepare, or
+**
+**  * The sqlite3ValueFromExpr() function is able to extract a value
+**    from the expression (i.e. the expression is a literal value).
+**
+** Or, if pExpr is a TK_VECTOR, one field is populated for each of the
+** vector components that match either of the two latter criteria listed
+** above.
+**
+** Before any value is appended to the record, the affinity of the
+** corresponding column within index pIdx is applied to it. Before
+** this function returns, output parameter *pnExtract is set to the
+** number of values appended to the record.
+**
+** When this function is called, *ppRec must either point to an object
+** allocated by an earlier call to this function, or must be NULL. If it
+** is NULL and a value can be successfully extracted, a new UnpackedRecord
+** is allocated (and *ppRec set to point to it) before returning.
+**
+** Unless an error is encountered, SQLITE_OK is returned. It is not an
+** error if a value cannot be extracted from pExpr. If an error does
+** occur, an SQLite error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3Stat4ProbeSetValue(
+  Parse *pParse,                  /* Parse context */
+  Index *pIdx,                    /* Index being probed */
+  UnpackedRecord **ppRec,         /* IN/OUT: Probe record */
+  Expr *pExpr,                    /* The expression to extract a value from */
+  int nElem,                      /* Maximum number of values to append */
+  int iVal,                       /* Array element to populate */
+  int *pnExtract                  /* OUT: Values appended to the record */
+){
+  int rc = SQLITE_OK;
+  int nExtract = 0;
+
+  if( pExpr==0 || pExpr->op!=TK_SELECT ){
+    int i;
+    struct ValueNewStat4Ctx alloc;
+
+    alloc.pParse = pParse;
+    alloc.pIdx = pIdx;
+    alloc.ppRec = ppRec;
+
+    for(i=0; i<nElem; i++){
+      sqlite3_value *pVal = 0;
+      Expr *pElem = (pExpr ? sqlite3VectorFieldSubexpr(pExpr, i) : 0);
+      u8 aff = sqlite3IndexColumnAffinity(pParse->db, pIdx, iVal+i);
+      alloc.iVal = iVal+i;
+      rc = stat4ValueFromExpr(pParse, pElem, aff, &alloc, &pVal);
+      if( !pVal ) break;
+      nExtract++;
+    }
+  }
+
+  *pnExtract = nExtract;
+  return rc;
+}
+
+/*
+** Attempt to extract a value from expression pExpr using the methods
+** as described for sqlite3Stat4ProbeSetValue() above.
+**
+** If successful, set *ppVal to point to a new value object and return
+** SQLITE_OK. If no value can be extracted, but no other error occurs
+** (e.g. OOM), return SQLITE_OK and set *ppVal to NULL. Or, if an error
+** does occur, return an SQLite error code. The final value of *ppVal
+** is undefined in this case.
+*/
+SQLITE_PRIVATE int sqlite3Stat4ValueFromExpr(
+  Parse *pParse,                  /* Parse context */
+  Expr *pExpr,                    /* The expression to extract a value from */
+  u8 affinity,                    /* Affinity to use */
+  sqlite3_value **ppVal           /* OUT: New value object (or NULL) */
+){
+  return stat4ValueFromExpr(pParse, pExpr, affinity, 0, ppVal);
+}
+
+/*
+** Extract the iCol-th column from the nRec-byte record in pRec.  Write
+** the column value into *ppVal.  If *ppVal is initially NULL then a new
+** sqlite3_value object is allocated.
+**
+** If *ppVal is initially NULL then the caller is responsible for
+** ensuring that the value written into *ppVal is eventually freed.
+*/
+SQLITE_PRIVATE int sqlite3Stat4Column(
+  sqlite3 *db,                    /* Database handle */
+  const void *pRec,               /* Pointer to buffer containing record */
+  int nRec,                       /* Size of buffer pRec in bytes */
+  int iCol,                       /* Column to extract */
+  sqlite3_value **ppVal           /* OUT: Extracted value */
+){
+  u32 t = 0;                      /* a column type code */
+  u32 nHdr;                       /* Size of the header in the record */
+  u32 iHdr;                       /* Next unread header byte */
+  i64 iField;                     /* Next unread data byte */
+  u32 szField = 0;                /* Size of the current data field */
+  int i;                          /* Column index */
+  u8 *a = (u8*)pRec;              /* Typecast byte array */
+  Mem *pMem = *ppVal;             /* Write result into this Mem object */
+
+  assert( iCol>0 );
+  iHdr = getVarint32(a, nHdr);
+  if( nHdr>(u32)nRec || iHdr>=nHdr ) return SQLITE_CORRUPT_BKPT;
+  iField = nHdr;
+  for(i=0; i<=iCol; i++){
+    iHdr += getVarint32(&a[iHdr], t);
+    testcase( iHdr==nHdr );
+    testcase( iHdr==nHdr+1 );
+    if( iHdr>nHdr ) return SQLITE_CORRUPT_BKPT;
+    szField = sqlite3VdbeSerialTypeLen(t);
+    iField += szField;
+  }
+  testcase( iField==nRec );
+  testcase( iField==nRec+1 );
+  if( iField>nRec ) return SQLITE_CORRUPT_BKPT;
+  if( pMem==0 ){
+    pMem = *ppVal = sqlite3ValueNew(db);
+    if( pMem==0 ) return SQLITE_NOMEM_BKPT;
+  }
+  sqlite3VdbeSerialGet(&a[iField-szField], t, pMem);
+  pMem->enc = ENC(db);
+  return SQLITE_OK;
+}
+
+/*
+** Unless it is NULL, the argument must be an UnpackedRecord object returned
+** by an earlier call to sqlite3Stat4ProbeSetValue(). This call deletes
+** the object.
+*/
+SQLITE_PRIVATE void sqlite3Stat4ProbeFree(UnpackedRecord *pRec){
+  if( pRec ){
+    int i;
+    int nCol = pRec->pKeyInfo->nAllField;
+    Mem *aMem = pRec->aMem;
+    sqlite3 *db = aMem[0].db;
+    for(i=0; i<nCol; i++){
+      sqlite3VdbeMemRelease(&aMem[i]);
+    }
+    sqlite3KeyInfoUnref(pRec->pKeyInfo);
+    sqlite3DbFreeNN(db, pRec);
+  }
+}
+#endif /* ifdef SQLITE_ENABLE_STAT4 */
+
+/*
+** Change the string value of an sqlite3_value object
+*/
+SQLITE_PRIVATE void sqlite3ValueSetStr(
+  sqlite3_value *v,     /* Value to be set */
+  int n,                /* Length of string z */
+  const void *z,        /* Text of the new string */
+  u8 enc,               /* Encoding to use */
+  void (*xDel)(void*)   /* Destructor for the string */
+){
+  if( v ) sqlite3VdbeMemSetStr((Mem *)v, z, n, enc, xDel);
+}
+
+/*
+** Free an sqlite3_value object
+*/
+SQLITE_PRIVATE void sqlite3ValueFree(sqlite3_value *v){
+  if( !v ) return;
+  sqlite3VdbeMemRelease((Mem *)v);
+  sqlite3DbFreeNN(((Mem*)v)->db, v);
+}
+
+/*
+** The sqlite3ValueBytes() routine returns the number of bytes in the
+** sqlite3_value object assuming that it uses the encoding "enc".
+** The valueBytes() routine is a helper function.
+*/
+static SQLITE_NOINLINE int valueBytes(sqlite3_value *pVal, u8 enc){
+  return valueToText(pVal, enc)!=0 ? pVal->n : 0;
+}
+SQLITE_PRIVATE int sqlite3ValueBytes(sqlite3_value *pVal, u8 enc){
+  Mem *p = (Mem*)pVal;
+  assert( (p->flags & MEM_Null)==0 || (p->flags & (MEM_Str|MEM_Blob))==0 );
+  if( (p->flags & MEM_Str)!=0 && pVal->enc==enc ){
+    return p->n;
+  }
+  if( (p->flags & MEM_Str)!=0 && enc!=SQLITE_UTF8 && pVal->enc!=SQLITE_UTF8 ){
+    return p->n;
+  }
+  if( (p->flags & MEM_Blob)!=0 ){
+    if( p->flags & MEM_Zero ){
+      return p->n + p->u.nZero;
+    }else{
+      return p->n;
+    }
+  }
+  if( p->flags & MEM_Null ) return 0;
+  return valueBytes(pVal, enc);
+}
+
+/************** End of vdbemem.c *********************************************/
+/************** Begin file vdbeaux.c *****************************************/
+/*
+** 2003 September 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used for creating, destroying, and populating
+** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+/* Forward references */
+static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef);
+static void vdbeFreeOpArray(sqlite3 *, Op *, int);
+
+/*
+** Create a new virtual database engine.
+*/
+SQLITE_PRIVATE Vdbe *sqlite3VdbeCreate(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  Vdbe *p;
+  p = sqlite3DbMallocRawNN(db, sizeof(Vdbe) );
+  if( p==0 ) return 0;
+  memset(&p->aOp, 0, sizeof(Vdbe)-offsetof(Vdbe,aOp));
+  p->db = db;
+  if( db->pVdbe ){
+    db->pVdbe->ppVPrev = &p->pVNext;
+  }
+  p->pVNext = db->pVdbe;
+  p->ppVPrev = &db->pVdbe;
+  db->pVdbe = p;
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  p->pParse = pParse;
+  pParse->pVdbe = p;
+  assert( pParse->aLabel==0 );
+  assert( pParse->nLabel==0 );
+  assert( p->nOpAlloc==0 );
+  assert( pParse->szOpAlloc==0 );
+  sqlite3VdbeAddOp2(p, OP_Init, 0, 1);
+  return p;
+}
+
+/*
+** Return the Parse object that owns a Vdbe object.
+*/
+SQLITE_PRIVATE Parse *sqlite3VdbeParser(Vdbe *p){
+  return p->pParse;
+}
+
+/*
+** Change the error string stored in Vdbe.zErrMsg
+*/
+SQLITE_PRIVATE void sqlite3VdbeError(Vdbe *p, const char *zFormat, ...){
+  va_list ap;
+  sqlite3DbFree(p->db, p->zErrMsg);
+  va_start(ap, zFormat);
+  p->zErrMsg = sqlite3VMPrintf(p->db, zFormat, ap);
+  va_end(ap);
+}
+
+/*
+** Remember the SQL string for a prepared statement.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe *p, const char *z, int n, u8 prepFlags){
+  if( p==0 ) return;
+  p->prepFlags = prepFlags;
+  if( (prepFlags & SQLITE_PREPARE_SAVESQL)==0 ){
+    p->expmask = 0;
+  }
+  assert( p->zSql==0 );
+  p->zSql = sqlite3DbStrNDup(p->db, z, n);
+}
+
+#ifdef SQLITE_ENABLE_NORMALIZE
+/*
+** Add a new element to the Vdbe->pDblStr list.
+*/
+SQLITE_PRIVATE void sqlite3VdbeAddDblquoteStr(sqlite3 *db, Vdbe *p, const char *z){
+  if( p ){
+    int n = sqlite3Strlen30(z);
+    DblquoteStr *pStr = sqlite3DbMallocRawNN(db,
+                            sizeof(*pStr)+n+1-sizeof(pStr->z));
+    if( pStr ){
+      pStr->pNextStr = p->pDblStr;
+      p->pDblStr = pStr;
+      memcpy(pStr->z, z, n+1);
+    }
+  }
+}
+#endif
+
+#ifdef SQLITE_ENABLE_NORMALIZE
+/*
+** zId of length nId is a double-quoted identifier.  Check to see if
+** that identifier is really used as a string literal.
+*/
+SQLITE_PRIVATE int sqlite3VdbeUsesDoubleQuotedString(
+  Vdbe *pVdbe,            /* The prepared statement */
+  const char *zId         /* The double-quoted identifier, already dequoted */
+){
+  DblquoteStr *pStr;
+  assert( zId!=0 );
+  if( pVdbe->pDblStr==0 ) return 0;
+  for(pStr=pVdbe->pDblStr; pStr; pStr=pStr->pNextStr){
+    if( strcmp(zId, pStr->z)==0 ) return 1;
+  }
+  return 0;
+}
+#endif
+
+/*
+** Swap byte-code between two VDBE structures.
+**
+** This happens after pB was previously run and returned
+** SQLITE_SCHEMA.  The statement was then reprepared in pA.
+** This routine transfers the new bytecode in pA over to pB
+** so that pB can be run again.  The old pB byte code is
+** moved back to pA so that it will be cleaned up when pA is
+** finalized.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe *pA, Vdbe *pB){
+  Vdbe tmp, *pTmp, **ppTmp;
+  char *zTmp;
+  assert( pA->db==pB->db );
+  tmp = *pA;
+  *pA = *pB;
+  *pB = tmp;
+  pTmp = pA->pVNext;
+  pA->pVNext = pB->pVNext;
+  pB->pVNext = pTmp;
+  ppTmp = pA->ppVPrev;
+  pA->ppVPrev = pB->ppVPrev;
+  pB->ppVPrev = ppTmp;
+  zTmp = pA->zSql;
+  pA->zSql = pB->zSql;
+  pB->zSql = zTmp;
+#ifdef SQLITE_ENABLE_NORMALIZE
+  zTmp = pA->zNormSql;
+  pA->zNormSql = pB->zNormSql;
+  pB->zNormSql = zTmp;
+#endif
+  pB->expmask = pA->expmask;
+  pB->prepFlags = pA->prepFlags;
+  memcpy(pB->aCounter, pA->aCounter, sizeof(pB->aCounter));
+  pB->aCounter[SQLITE_STMTSTATUS_REPREPARE]++;
+}
+
+/*
+** Resize the Vdbe.aOp array so that it is at least nOp elements larger
+** than its current size. nOp is guaranteed to be less than or equal
+** to 1024/sizeof(Op).
+**
+** If an out-of-memory error occurs while resizing the array, return
+** SQLITE_NOMEM. In this case Vdbe.aOp and Vdbe.nOpAlloc remain
+** unchanged (this is so that any opcodes already allocated can be
+** correctly deallocated along with the rest of the Vdbe).
+*/
+static int growOpArray(Vdbe *v, int nOp){
+  VdbeOp *pNew;
+  Parse *p = v->pParse;
+
+  /* The SQLITE_TEST_REALLOC_STRESS compile-time option is designed to force
+  ** more frequent reallocs and hence provide more opportunities for
+  ** simulated OOM faults.  SQLITE_TEST_REALLOC_STRESS is generally used
+  ** during testing only.  With SQLITE_TEST_REALLOC_STRESS grow the op array
+  ** by the minimum* amount required until the size reaches 512.  Normal
+  ** operation (without SQLITE_TEST_REALLOC_STRESS) is to double the current
+  ** size of the op array or add 1KB of space, whichever is smaller. */
+#ifdef SQLITE_TEST_REALLOC_STRESS
+  sqlite3_int64 nNew = (v->nOpAlloc>=512 ? 2*(sqlite3_int64)v->nOpAlloc
+                        : (sqlite3_int64)v->nOpAlloc+nOp);
+#else
+  sqlite3_int64 nNew = (v->nOpAlloc ? 2*(sqlite3_int64)v->nOpAlloc
+                        : (sqlite3_int64)(1024/sizeof(Op)));
+  UNUSED_PARAMETER(nOp);
+#endif
+
+  /* Ensure that the size of a VDBE does not grow too large */
+  if( nNew > p->db->aLimit[SQLITE_LIMIT_VDBE_OP] ){
+    sqlite3OomFault(p->db);
+    return SQLITE_NOMEM;
+  }
+
+  assert( nOp<=(int)(1024/sizeof(Op)) );
+  assert( nNew>=(v->nOpAlloc+nOp) );
+  pNew = sqlite3DbRealloc(p->db, v->aOp, nNew*sizeof(Op));
+  if( pNew ){
+    p->szOpAlloc = sqlite3DbMallocSize(p->db, pNew);
+    v->nOpAlloc = p->szOpAlloc/sizeof(Op);
+    v->aOp = pNew;
+  }
+  return (pNew ? SQLITE_OK : SQLITE_NOMEM_BKPT);
+}
+
+#ifdef SQLITE_DEBUG
+/* This routine is just a convenient place to set a breakpoint that will
+** fire after each opcode is inserted and displayed using
+** "PRAGMA vdbe_addoptrace=on".  Parameters "pc" (program counter) and
+** pOp are available to make the breakpoint conditional.
+**
+** Other useful labels for breakpoints include:
+**   test_trace_breakpoint(pc,pOp)
+**   sqlite3CorruptError(lineno)
+**   sqlite3MisuseError(lineno)
+**   sqlite3CantopenError(lineno)
+*/
+static void test_addop_breakpoint(int pc, Op *pOp){
+  static u64 n = 0;
+  (void)pc;
+  (void)pOp;
+  n++;
+  if( n==LARGEST_UINT64 ) abort(); /* so that n is used, preventing a warning */
+}
+#endif
+
+/*
+** Slow paths for sqlite3VdbeAddOp3() and sqlite3VdbeAddOp4Int() for the
+** unusual case when we need to increase the size of the Vdbe.aOp[] array
+** before adding the new opcode.
+*/
+static SQLITE_NOINLINE int growOp3(Vdbe *p, int op, int p1, int p2, int p3){
+  assert( p->nOpAlloc<=p->nOp );
+  if( growOpArray(p, 1) ) return 1;
+  assert( p->nOpAlloc>p->nOp );
+  return sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+}
+static SQLITE_NOINLINE int addOp4IntSlow(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  int p4              /* The P4 operand as an integer */
+){
+  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+  if( p->db->mallocFailed==0 ){
+    VdbeOp *pOp = &p->aOp[addr];
+    pOp->p4type = P4_INT32;
+    pOp->p4.i = p4;
+  }
+  return addr;
+}
+
+
+/*
+** Add a new instruction to the list of instructions current in the
+** VDBE.  Return the address of the new instruction.
+**
+** Parameters:
+**
+**    p               Pointer to the VDBE
+**
+**    op              The opcode for this instruction
+**
+**    p1, p2, p3, p4  Operands
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp0(Vdbe *p, int op){
+  return sqlite3VdbeAddOp3(p, op, 0, 0, 0);
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp1(Vdbe *p, int op, int p1){
+  return sqlite3VdbeAddOp3(p, op, p1, 0, 0);
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp2(Vdbe *p, int op, int p1, int p2){
+  return sqlite3VdbeAddOp3(p, op, p1, p2, 0);
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){
+  int i;
+  VdbeOp *pOp;
+
+  i = p->nOp;
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  assert( op>=0 && op<0xff );
+  if( p->nOpAlloc<=i ){
+    return growOp3(p, op, p1, p2, p3);
+  }
+  assert( p->aOp!=0 );
+  p->nOp++;
+  pOp = &p->aOp[i];
+  assert( pOp!=0 );
+  pOp->opcode = (u8)op;
+  pOp->p5 = 0;
+  pOp->p1 = p1;
+  pOp->p2 = p2;
+  pOp->p3 = p3;
+  pOp->p4.p = 0;
+  pOp->p4type = P4_NOTUSED;
+
+  /* Replicate this logic in sqlite3VdbeAddOp4Int()
+  ** vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv   */
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  pOp->zComment = 0;
+#endif
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
+  pOp->nExec = 0;
+  pOp->nCycle = 0;
+#endif
+#ifdef SQLITE_DEBUG
+  if( p->db->flags & SQLITE_VdbeAddopTrace ){
+    sqlite3VdbePrintOp(0, i, &p->aOp[i]);
+    test_addop_breakpoint(i, &p->aOp[i]);
+  }
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  pOp->iSrcLine = 0;
+#endif
+  /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  ** Replicate in sqlite3VdbeAddOp4Int() */
+
+  return i;
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Int(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  int p4              /* The P4 operand as an integer */
+){
+  int i;
+  VdbeOp *pOp;
+
+  i = p->nOp;
+  if( p->nOpAlloc<=i ){
+    return addOp4IntSlow(p, op, p1, p2, p3, p4);
+  }
+  p->nOp++;
+  pOp = &p->aOp[i];
+  assert( pOp!=0 );
+  pOp->opcode = (u8)op;
+  pOp->p5 = 0;
+  pOp->p1 = p1;
+  pOp->p2 = p2;
+  pOp->p3 = p3;
+  pOp->p4.i = p4;
+  pOp->p4type = P4_INT32;
+
+  /* Replicate this logic in sqlite3VdbeAddOp3()
+  ** vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv   */
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  pOp->zComment = 0;
+#endif
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
+  pOp->nExec = 0;
+  pOp->nCycle = 0;
+#endif
+#ifdef SQLITE_DEBUG
+  if( p->db->flags & SQLITE_VdbeAddopTrace ){
+    sqlite3VdbePrintOp(0, i, &p->aOp[i]);
+    test_addop_breakpoint(i, &p->aOp[i]);
+  }
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  pOp->iSrcLine = 0;
+#endif
+  /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  ** Replicate in sqlite3VdbeAddOp3() */
+
+  return i;
+}
+
+/* Generate code for an unconditional jump to instruction iDest
+*/
+SQLITE_PRIVATE int sqlite3VdbeGoto(Vdbe *p, int iDest){
+  return sqlite3VdbeAddOp3(p, OP_Goto, 0, iDest, 0);
+}
+
+/* Generate code to cause the string zStr to be loaded into
+** register iDest
+*/
+SQLITE_PRIVATE int sqlite3VdbeLoadString(Vdbe *p, int iDest, const char *zStr){
+  return sqlite3VdbeAddOp4(p, OP_String8, 0, iDest, 0, zStr, 0);
+}
+
+/*
+** Generate code that initializes multiple registers to string or integer
+** constants.  The registers begin with iDest and increase consecutively.
+** One register is initialized for each characgter in zTypes[].  For each
+** "s" character in zTypes[], the register is a string if the argument is
+** not NULL, or OP_Null if the value is a null pointer.  For each "i" character
+** in zTypes[], the register is initialized to an integer.
+**
+** If the input string does not end with "X" then an OP_ResultRow instruction
+** is generated for the values inserted.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMultiLoad(Vdbe *p, int iDest, const char *zTypes, ...){
+  va_list ap;
+  int i;
+  char c;
+  va_start(ap, zTypes);
+  for(i=0; (c = zTypes[i])!=0; i++){
+    if( c=='s' ){
+      const char *z = va_arg(ap, const char*);
+      sqlite3VdbeAddOp4(p, z==0 ? OP_Null : OP_String8, 0, iDest+i, 0, z, 0);
+    }else if( c=='i' ){
+      sqlite3VdbeAddOp2(p, OP_Integer, va_arg(ap, int), iDest+i);
+    }else{
+      goto skip_op_resultrow;
+    }
+  }
+  sqlite3VdbeAddOp2(p, OP_ResultRow, iDest, i);
+skip_op_resultrow:
+  va_end(ap);
+}
+
+/*
+** Add an opcode that includes the p4 value as a pointer.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp4(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  const char *zP4,    /* The P4 operand */
+  int p4type          /* P4 operand type */
+){
+  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+  sqlite3VdbeChangeP4(p, addr, zP4, p4type);
+  return addr;
+}
+
+/*
+** Add an OP_Function or OP_PureFunc opcode.
+**
+** The eCallCtx argument is information (typically taken from Expr.op2)
+** that describes the calling context of the function.  0 means a general
+** function call.  NC_IsCheck means called by a check constraint,
+** NC_IdxExpr means called as part of an index expression.  NC_PartIdx
+** means in the WHERE clause of a partial index.  NC_GenCol means called
+** while computing a generated column value.  0 is the usual case.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddFunctionCall(
+  Parse *pParse,        /* Parsing context */
+  int p1,               /* Constant argument mask */
+  int p2,               /* First argument register */
+  int p3,               /* Register into which results are written */
+  int nArg,             /* Number of argument */
+  const FuncDef *pFunc, /* The function to be invoked */
+  int eCallCtx          /* Calling context */
+){
+  Vdbe *v = pParse->pVdbe;
+  int nByte;
+  int addr;
+  sqlite3_context *pCtx;
+  assert( v );
+  nByte = sizeof(*pCtx) + (nArg-1)*sizeof(sqlite3_value*);
+  pCtx = sqlite3DbMallocRawNN(pParse->db, nByte);
+  if( pCtx==0 ){
+    assert( pParse->db->mallocFailed );
+    freeEphemeralFunction(pParse->db, (FuncDef*)pFunc);
+    return 0;
+  }
+  pCtx->pOut = 0;
+  pCtx->pFunc = (FuncDef*)pFunc;
+  pCtx->pVdbe = 0;
+  pCtx->isError = 0;
+  pCtx->argc = nArg;
+  pCtx->iOp = sqlite3VdbeCurrentAddr(v);
+  addr = sqlite3VdbeAddOp4(v, eCallCtx ? OP_PureFunc : OP_Function,
+                           p1, p2, p3, (char*)pCtx, P4_FUNCCTX);
+  sqlite3VdbeChangeP5(v, eCallCtx & NC_SelfRef);
+  sqlite3MayAbort(pParse);
+  return addr;
+}
+
+/*
+** Add an opcode that includes the p4 value with a P4_INT64 or
+** P4_REAL type.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Dup8(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  const u8 *zP4,      /* The P4 operand */
+  int p4type          /* P4 operand type */
+){
+  char *p4copy = sqlite3DbMallocRawNN(sqlite3VdbeDb(p), 8);
+  if( p4copy ) memcpy(p4copy, zP4, 8);
+  return sqlite3VdbeAddOp4(p, op, p1, p2, p3, p4copy, p4type);
+}
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Return the address of the current EXPLAIN QUERY PLAN baseline.
+** 0 means "none".
+*/
+SQLITE_PRIVATE int sqlite3VdbeExplainParent(Parse *pParse){
+  VdbeOp *pOp;
+  if( pParse->addrExplain==0 ) return 0;
+  pOp = sqlite3VdbeGetOp(pParse->pVdbe, pParse->addrExplain);
+  return pOp->p2;
+}
+
+/*
+** Set a debugger breakpoint on the following routine in order to
+** monitor the EXPLAIN QUERY PLAN code generation.
+*/
+#if defined(SQLITE_DEBUG)
+SQLITE_PRIVATE void sqlite3ExplainBreakpoint(const char *z1, const char *z2){
+  (void)z1;
+  (void)z2;
+}
+#endif
+
+/*
+** Add a new OP_Explain opcode.
+**
+** If the bPush flag is true, then make this opcode the parent for
+** subsequent Explains until sqlite3VdbeExplainPop() is called.
+*/
+SQLITE_PRIVATE int sqlite3VdbeExplain(Parse *pParse, u8 bPush, const char *zFmt, ...){
+  int addr = 0;
+#if !defined(SQLITE_DEBUG)
+  /* Always include the OP_Explain opcodes if SQLITE_DEBUG is defined.
+  ** But omit them (for performance) during production builds */
+  if( pParse->explain==2 || IS_STMT_SCANSTATUS(pParse->db) )
+#endif
+  {
+    char *zMsg;
+    Vdbe *v;
+    va_list ap;
+    int iThis;
+    va_start(ap, zFmt);
+    zMsg = sqlite3VMPrintf(pParse->db, zFmt, ap);
+    va_end(ap);
+    v = pParse->pVdbe;
+    iThis = v->nOp;
+    addr = sqlite3VdbeAddOp4(v, OP_Explain, iThis, pParse->addrExplain, 0,
+                      zMsg, P4_DYNAMIC);
+    sqlite3ExplainBreakpoint(bPush?"PUSH":"", sqlite3VdbeGetLastOp(v)->p4.z);
+    if( bPush){
+      pParse->addrExplain = iThis;
+    }
+    sqlite3VdbeScanStatus(v, iThis, -1, -1, 0, 0);
+  }
+  return addr;
+}
+
+/*
+** Pop the EXPLAIN QUERY PLAN stack one level.
+*/
+SQLITE_PRIVATE void sqlite3VdbeExplainPop(Parse *pParse){
+  sqlite3ExplainBreakpoint("POP", 0);
+  pParse->addrExplain = sqlite3VdbeExplainParent(pParse);
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+
+/*
+** Add an OP_ParseSchema opcode.  This routine is broken out from
+** sqlite3VdbeAddOp4() since it needs to also needs to mark all btrees
+** as having been used.
+**
+** The zWhere string must have been obtained from sqlite3_malloc().
+** This routine will take ownership of the allocated memory.
+*/
+SQLITE_PRIVATE void sqlite3VdbeAddParseSchemaOp(Vdbe *p, int iDb, char *zWhere, u16 p5){
+  int j;
+  sqlite3VdbeAddOp4(p, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);
+  sqlite3VdbeChangeP5(p, p5);
+  for(j=0; j<p->db->nDb; j++) sqlite3VdbeUsesBtree(p, j);
+  sqlite3MayAbort(p->pParse);
+}
+
+/* Insert the end of a co-routine
+*/
+SQLITE_PRIVATE void sqlite3VdbeEndCoroutine(Vdbe *v, int regYield){
+  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regYield);
+
+  /* Clear the temporary register cache, thereby ensuring that each
+  ** co-routine has its own independent set of registers, because co-routines
+  ** might expect their registers to be preserved across an OP_Yield, and
+  ** that could cause problems if two or more co-routines are using the same
+  ** temporary register.
+  */
+  v->pParse->nTempReg = 0;
+  v->pParse->nRangeReg = 0;
+}
+
+/*
+** Create a new symbolic label for an instruction that has yet to be
+** coded.  The symbolic label is really just a negative number.  The
+** label can be used as the P2 value of an operation.  Later, when
+** the label is resolved to a specific address, the VDBE will scan
+** through its operation list and change all values of P2 which match
+** the label into the resolved address.
+**
+** The VDBE knows that a P2 value is a label because labels are
+** always negative and P2 values are suppose to be non-negative.
+** Hence, a negative P2 value is a label that has yet to be resolved.
+** (Later:) This is only true for opcodes that have the OPFLG_JUMP
+** property.
+**
+** Variable usage notes:
+**
+**     Parse.aLabel[x]     Stores the address that the x-th label resolves
+**                         into.  For testing (SQLITE_DEBUG), unresolved
+**                         labels stores -1, but that is not required.
+**     Parse.nLabelAlloc   Number of slots allocated to Parse.aLabel[]
+**     Parse.nLabel        The *negative* of the number of labels that have
+**                         been issued.  The negative is stored because
+**                         that gives a performance improvement over storing
+**                         the equivalent positive value.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMakeLabel(Parse *pParse){
+  return --pParse->nLabel;
+}
+
+/*
+** Resolve label "x" to be the address of the next instruction to
+** be inserted.  The parameter "x" must have been obtained from
+** a prior call to sqlite3VdbeMakeLabel().
+*/
+static SQLITE_NOINLINE void resizeResolveLabel(Parse *p, Vdbe *v, int j){
+  int nNewSize = 10 - p->nLabel;
+  p->aLabel = sqlite3DbReallocOrFree(p->db, p->aLabel,
+                     nNewSize*sizeof(p->aLabel[0]));
+  if( p->aLabel==0 ){
+    p->nLabelAlloc = 0;
+  }else{
+#ifdef SQLITE_DEBUG
+    int i;
+    for(i=p->nLabelAlloc; i<nNewSize; i++) p->aLabel[i] = -1;
+#endif
+    if( nNewSize>=100 && (nNewSize/100)>(p->nLabelAlloc/100) ){
+      sqlite3ProgressCheck(p);
+    }
+    p->nLabelAlloc = nNewSize;
+    p->aLabel[j] = v->nOp;
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe *v, int x){
+  Parse *p = v->pParse;
+  int j = ADDR(x);
+  assert( v->eVdbeState==VDBE_INIT_STATE );
+  assert( j<-p->nLabel );
+  assert( j>=0 );
+#ifdef SQLITE_DEBUG
+  if( p->db->flags & SQLITE_VdbeAddopTrace ){
+    printf("RESOLVE LABEL %d to %d\n", x, v->nOp);
+  }
+#endif
+  if( p->nLabelAlloc + p->nLabel < 0 ){
+    resizeResolveLabel(p,v,j);
+  }else{
+    assert( p->aLabel[j]==(-1) ); /* Labels may only be resolved once */
+    p->aLabel[j] = v->nOp;
+  }
+}
+
+/*
+** Mark the VDBE as one that can only be run one time.
+*/
+SQLITE_PRIVATE void sqlite3VdbeRunOnlyOnce(Vdbe *p){
+  sqlite3VdbeAddOp2(p, OP_Expire, 1, 1);
+}
+
+/*
+** Mark the VDBE as one that can be run multiple times.
+*/
+SQLITE_PRIVATE void sqlite3VdbeReusable(Vdbe *p){
+  int i;
+  for(i=1; ALWAYS(i<p->nOp); i++){
+    if( ALWAYS(p->aOp[i].opcode==OP_Expire) ){
+      p->aOp[1].opcode = OP_Noop;
+      break;
+    }
+  }
+}
+
+#ifdef SQLITE_DEBUG /* sqlite3AssertMayAbort() logic */
+
+/*
+** The following type and function are used to iterate through all opcodes
+** in a Vdbe main program and each of the sub-programs (triggers) it may
+** invoke directly or indirectly. It should be used as follows:
+**
+**   Op *pOp;
+**   VdbeOpIter sIter;
+**
+**   memset(&sIter, 0, sizeof(sIter));
+**   sIter.v = v;                            // v is of type Vdbe*
+**   while( (pOp = opIterNext(&sIter)) ){
+**     // Do something with pOp
+**   }
+**   sqlite3DbFree(v->db, sIter.apSub);
+**
+*/
+typedef struct VdbeOpIter VdbeOpIter;
+struct VdbeOpIter {
+  Vdbe *v;                   /* Vdbe to iterate through the opcodes of */
+  SubProgram **apSub;        /* Array of subprograms */
+  int nSub;                  /* Number of entries in apSub */
+  int iAddr;                 /* Address of next instruction to return */
+  int iSub;                  /* 0 = main program, 1 = first sub-program etc. */
+};
+static Op *opIterNext(VdbeOpIter *p){
+  Vdbe *v = p->v;
+  Op *pRet = 0;
+  Op *aOp;
+  int nOp;
+
+  if( p->iSub<=p->nSub ){
+
+    if( p->iSub==0 ){
+      aOp = v->aOp;
+      nOp = v->nOp;
+    }else{
+      aOp = p->apSub[p->iSub-1]->aOp;
+      nOp = p->apSub[p->iSub-1]->nOp;
+    }
+    assert( p->iAddr<nOp );
+
+    pRet = &aOp[p->iAddr];
+    p->iAddr++;
+    if( p->iAddr==nOp ){
+      p->iSub++;
+      p->iAddr = 0;
+    }
+
+    if( pRet->p4type==P4_SUBPROGRAM ){
+      int nByte = (p->nSub+1)*sizeof(SubProgram*);
+      int j;
+      for(j=0; j<p->nSub; j++){
+        if( p->apSub[j]==pRet->p4.pProgram ) break;
+      }
+      if( j==p->nSub ){
+        p->apSub = sqlite3DbReallocOrFree(v->db, p->apSub, nByte);
+        if( !p->apSub ){
+          pRet = 0;
+        }else{
+          p->apSub[p->nSub++] = pRet->p4.pProgram;
+        }
+      }
+    }
+  }
+
+  return pRet;
+}
+
+/*
+** Check if the program stored in the VM associated with pParse may
+** throw an ABORT exception (causing the statement, but not entire transaction
+** to be rolled back). This condition is true if the main program or any
+** sub-programs contains any of the following:
+**
+**   *  OP_Halt with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
+**   *  OP_HaltIfNull with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
+**   *  OP_Destroy
+**   *  OP_VUpdate
+**   *  OP_VCreate
+**   *  OP_VRename
+**   *  OP_FkCounter with P2==0 (immediate foreign key constraint)
+**   *  OP_CreateBtree/BTREE_INTKEY and OP_InitCoroutine
+**      (for CREATE TABLE AS SELECT ...)
+**
+** Then check that the value of Parse.mayAbort is true if an
+** ABORT may be thrown, or false otherwise. Return true if it does
+** match, or false otherwise. This function is intended to be used as
+** part of an assert statement in the compiler. Similar to:
+**
+**   assert( sqlite3VdbeAssertMayAbort(pParse->pVdbe, pParse->mayAbort) );
+*/
+SQLITE_PRIVATE int sqlite3VdbeAssertMayAbort(Vdbe *v, int mayAbort){
+  int hasAbort = 0;
+  int hasFkCounter = 0;
+  int hasCreateTable = 0;
+  int hasCreateIndex = 0;
+  int hasInitCoroutine = 0;
+  Op *pOp;
+  VdbeOpIter sIter;
+
+  if( v==0 ) return 0;
+  memset(&sIter, 0, sizeof(sIter));
+  sIter.v = v;
+
+  while( (pOp = opIterNext(&sIter))!=0 ){
+    int opcode = pOp->opcode;
+    if( opcode==OP_Destroy || opcode==OP_VUpdate || opcode==OP_VRename
+     || opcode==OP_VDestroy
+     || opcode==OP_VCreate
+     || opcode==OP_ParseSchema
+     || opcode==OP_Function || opcode==OP_PureFunc
+     || ((opcode==OP_Halt || opcode==OP_HaltIfNull)
+      && ((pOp->p1)!=SQLITE_OK && pOp->p2==OE_Abort))
+    ){
+      hasAbort = 1;
+      break;
+    }
+    if( opcode==OP_CreateBtree && pOp->p3==BTREE_INTKEY ) hasCreateTable = 1;
+    if( mayAbort ){
+      /* hasCreateIndex may also be set for some DELETE statements that use
+      ** OP_Clear. So this routine may end up returning true in the case
+      ** where a "DELETE FROM tbl" has a statement-journal but does not
+      ** require one. This is not so bad - it is an inefficiency, not a bug. */
+      if( opcode==OP_CreateBtree && pOp->p3==BTREE_BLOBKEY ) hasCreateIndex = 1;
+      if( opcode==OP_Clear ) hasCreateIndex = 1;
+    }
+    if( opcode==OP_InitCoroutine ) hasInitCoroutine = 1;
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+    if( opcode==OP_FkCounter && pOp->p1==0 && pOp->p2==1 ){
+      hasFkCounter = 1;
+    }
+#endif
+  }
+  sqlite3DbFree(v->db, sIter.apSub);
+
+  /* Return true if hasAbort==mayAbort. Or if a malloc failure occurred.
+  ** If malloc failed, then the while() loop above may not have iterated
+  ** through all opcodes and hasAbort may be set incorrectly. Return
+  ** true for this case to prevent the assert() in the callers frame
+  ** from failing.  */
+  return ( v->db->mallocFailed || hasAbort==mayAbort || hasFkCounter
+        || (hasCreateTable && hasInitCoroutine) || hasCreateIndex
+  );
+}
+#endif /* SQLITE_DEBUG - the sqlite3AssertMayAbort() function */
+
+#ifdef SQLITE_DEBUG
+/*
+** Increment the nWrite counter in the VDBE if the cursor is not an
+** ephemeral cursor, or if the cursor argument is NULL.
+*/
+SQLITE_PRIVATE void sqlite3VdbeIncrWriteCounter(Vdbe *p, VdbeCursor *pC){
+  if( pC==0
+   || (pC->eCurType!=CURTYPE_SORTER
+       && pC->eCurType!=CURTYPE_PSEUDO
+       && !pC->isEphemeral)
+  ){
+    p->nWrite++;
+  }
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Assert if an Abort at this point in time might result in a corrupt
+** database.
+*/
+SQLITE_PRIVATE void sqlite3VdbeAssertAbortable(Vdbe *p){
+  assert( p->nWrite==0 || p->usesStmtJournal );
+}
+#endif
+
+/*
+** This routine is called after all opcodes have been inserted.  It loops
+** through all the opcodes and fixes up some details.
+**
+** (1) For each jump instruction with a negative P2 value (a label)
+**     resolve the P2 value to an actual address.
+**
+** (2) Compute the maximum number of arguments used by any SQL function
+**     and store that value in *pMaxFuncArgs.
+**
+** (3) Update the Vdbe.readOnly and Vdbe.bIsReader flags to accurately
+**     indicate what the prepared statement actually does.
+**
+** (4) (discontinued)
+**
+** (5) Reclaim the memory allocated for storing labels.
+**
+** This routine will only function correctly if the mkopcodeh.tcl generator
+** script numbers the opcodes correctly.  Changes to this routine must be
+** coordinated with changes to mkopcodeh.tcl.
+*/
+static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
+  int nMaxArgs = *pMaxFuncArgs;
+  Op *pOp;
+  Parse *pParse = p->pParse;
+  int *aLabel = pParse->aLabel;
+
+  assert( pParse->db->mallocFailed==0 ); /* tag-20230419-1 */
+  p->readOnly = 1;
+  p->bIsReader = 0;
+  pOp = &p->aOp[p->nOp-1];
+  assert( p->aOp[0].opcode==OP_Init );
+  while( 1 /* Loop terminates when it reaches the OP_Init opcode */ ){
+    /* Only JUMP opcodes and the short list of special opcodes in the switch
+    ** below need to be considered.  The mkopcodeh.tcl generator script groups
+    ** all these opcodes together near the front of the opcode list.  Skip
+    ** any opcode that does not need processing by virtual of the fact that
+    ** it is larger than SQLITE_MX_JUMP_OPCODE, as a performance optimization.
+    */
+    if( pOp->opcode<=SQLITE_MX_JUMP_OPCODE ){
+      /* NOTE: Be sure to update mkopcodeh.tcl when adding or removing
+      ** cases from this switch! */
+      switch( pOp->opcode ){
+        case OP_Transaction: {
+          if( pOp->p2!=0 ) p->readOnly = 0;
+          /* no break */ deliberate_fall_through
+        }
+        case OP_AutoCommit:
+        case OP_Savepoint: {
+          p->bIsReader = 1;
+          break;
+        }
+#ifndef SQLITE_OMIT_WAL
+        case OP_Checkpoint:
+#endif
+        case OP_Vacuum:
+        case OP_JournalMode: {
+          p->readOnly = 0;
+          p->bIsReader = 1;
+          break;
+        }
+        case OP_Init: {
+          assert( pOp->p2>=0 );
+          goto resolve_p2_values_loop_exit;
+        }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+        case OP_VUpdate: {
+          if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
+          break;
+        }
+        case OP_VFilter: {
+          int n;
+          assert( (pOp - p->aOp) >= 3 );
+          assert( pOp[-1].opcode==OP_Integer );
+          n = pOp[-1].p1;
+          if( n>nMaxArgs ) nMaxArgs = n;
+          /* Fall through into the default case */
+          /* no break */ deliberate_fall_through
+        }
+#endif
+        default: {
+          if( pOp->p2<0 ){
+            /* The mkopcodeh.tcl script has so arranged things that the only
+            ** non-jump opcodes less than SQLITE_MX_JUMP_CODE are guaranteed to
+            ** have non-negative values for P2. */
+            assert( (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_JUMP)!=0 );
+            assert( ADDR(pOp->p2)<-pParse->nLabel );
+            assert( aLabel!=0 );  /* True because of tag-20230419-1 */
+            pOp->p2 = aLabel[ADDR(pOp->p2)];
+          }
+
+          /* OPFLG_JUMP opcodes never have P2==0, though OPFLG_JUMP0 opcodes
+          ** might */
+          assert( pOp->p2>0
+                  || (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_JUMP0)!=0 );
+
+          /* Jumps never go off the end of the bytecode array */
+          assert( pOp->p2<p->nOp
+                  || (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_JUMP)==0 );
+          break;
+        }
+      }
+      /* The mkopcodeh.tcl script has so arranged things that the only
+      ** non-jump opcodes less than SQLITE_MX_JUMP_CODE are guaranteed to
+      ** have non-negative values for P2. */
+      assert( (sqlite3OpcodeProperty[pOp->opcode]&OPFLG_JUMP)==0 || pOp->p2>=0);
+    }
+    assert( pOp>p->aOp );
+    pOp--;
+  }
+resolve_p2_values_loop_exit:
+  if( aLabel ){
+    sqlite3DbNNFreeNN(p->db, pParse->aLabel);
+    pParse->aLabel = 0;
+  }
+  pParse->nLabel = 0;
+  *pMaxFuncArgs = nMaxArgs;
+  assert( p->bIsReader!=0 || DbMaskAllZero(p->btreeMask) );
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Check to see if a subroutine contains a jump to a location outside of
+** the subroutine.  If a jump outside the subroutine is detected, add code
+** that will cause the program to halt with an error message.
+**
+** The subroutine consists of opcodes between iFirst and iLast.  Jumps to
+** locations within the subroutine are acceptable.  iRetReg is a register
+** that contains the return address.  Jumps to outside the range of iFirst
+** through iLast are also acceptable as long as the jump destination is
+** an OP_Return to iReturnAddr.
+**
+** A jump to an unresolved label means that the jump destination will be
+** beyond the current address.  That is normally a jump to an early
+** termination and is consider acceptable.
+**
+** This routine only runs during debug builds.  The purpose is (of course)
+** to detect invalid escapes out of a subroutine.  The OP_Halt opcode
+** is generated rather than an assert() or other error, so that ".eqp full"
+** will still work to show the original bytecode, to aid in debugging.
+*/
+SQLITE_PRIVATE void sqlite3VdbeNoJumpsOutsideSubrtn(
+  Vdbe *v,          /* The byte-code program under construction */
+  int iFirst,       /* First opcode of the subroutine */
+  int iLast,        /* Last opcode of the subroutine */
+  int iRetReg       /* Subroutine return address register */
+){
+  VdbeOp *pOp;
+  Parse *pParse;
+  int i;
+  sqlite3_str *pErr = 0;
+  assert( v!=0 );
+  pParse = v->pParse;
+  assert( pParse!=0 );
+  if( pParse->nErr ) return;
+  assert( iLast>=iFirst );
+  assert( iLast<v->nOp );
+  pOp = &v->aOp[iFirst];
+  for(i=iFirst; i<=iLast; i++, pOp++){
+    if( (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_JUMP)!=0 ){
+      int iDest = pOp->p2;   /* Jump destination */
+      if( iDest==0 ) continue;
+      if( pOp->opcode==OP_Gosub ) continue;
+      if( pOp->p3==20230325 && pOp->opcode==OP_NotNull ){
+        /* This is a deliberately taken illegal branch.  tag-20230325-2 */
+        continue;
+      }
+      if( iDest<0 ){
+        int j = ADDR(iDest);
+        assert( j>=0 );
+        if( j>=-pParse->nLabel || pParse->aLabel[j]<0 ){
+          continue;
+        }
+        iDest = pParse->aLabel[j];
+      }
+      if( iDest<iFirst || iDest>iLast ){
+        int j = iDest;
+        for(; j<v->nOp; j++){
+          VdbeOp *pX = &v->aOp[j];
+          if( pX->opcode==OP_Return ){
+            if( pX->p1==iRetReg ) break;
+            continue;
+          }
+          if( pX->opcode==OP_Noop ) continue;
+          if( pX->opcode==OP_Explain ) continue;
+          if( pErr==0 ){
+            pErr = sqlite3_str_new(0);
+          }else{
+            sqlite3_str_appendchar(pErr, 1, '\n');
+          }
+          sqlite3_str_appendf(pErr,
+              "Opcode at %d jumps to %d which is outside the "
+              "subroutine at %d..%d",
+              i, iDest, iFirst, iLast);
+          break;
+        }
+      }
+    }
+  }
+  if( pErr ){
+    char *zErr = sqlite3_str_finish(pErr);
+    sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_INTERNAL, OE_Abort, 0, zErr, 0);
+    sqlite3_free(zErr);
+    sqlite3MayAbort(pParse);
+  }
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** Return the address of the next instruction to be inserted.
+*/
+SQLITE_PRIVATE int sqlite3VdbeCurrentAddr(Vdbe *p){
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  return p->nOp;
+}
+
+/*
+** Verify that at least N opcode slots are available in p without
+** having to malloc for more space (except when compiled using
+** SQLITE_TEST_REALLOC_STRESS).  This interface is used during testing
+** to verify that certain calls to sqlite3VdbeAddOpList() can never
+** fail due to a OOM fault and hence that the return value from
+** sqlite3VdbeAddOpList() will always be non-NULL.
+*/
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_TEST_REALLOC_STRESS)
+SQLITE_PRIVATE void sqlite3VdbeVerifyNoMallocRequired(Vdbe *p, int N){
+  assert( p->nOp + N <= p->nOpAlloc );
+}
+#endif
+
+/*
+** Verify that the VM passed as the only argument does not contain
+** an OP_ResultRow opcode. Fail an assert() if it does. This is used
+** by code in pragma.c to ensure that the implementation of certain
+** pragmas comports with the flags specified in the mkpragmatab.tcl
+** script.
+*/
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_TEST_REALLOC_STRESS)
+SQLITE_PRIVATE void sqlite3VdbeVerifyNoResultRow(Vdbe *p){
+  int i;
+  for(i=0; i<p->nOp; i++){
+    assert( p->aOp[i].opcode!=OP_ResultRow );
+  }
+}
+#endif
+
+/*
+** Generate code (a single OP_Abortable opcode) that will
+** verify that the VDBE program can safely call Abort in the current
+** context.
+*/
+#if defined(SQLITE_DEBUG)
+SQLITE_PRIVATE void sqlite3VdbeVerifyAbortable(Vdbe *p, int onError){
+  if( onError==OE_Abort ) sqlite3VdbeAddOp0(p, OP_Abortable);
+}
+#endif
+
+/*
+** This function returns a pointer to the array of opcodes associated with
+** the Vdbe passed as the first argument. It is the callers responsibility
+** to arrange for the returned array to be eventually freed using the
+** vdbeFreeOpArray() function.
+**
+** Before returning, *pnOp is set to the number of entries in the returned
+** array. Also, *pnMaxArg is set to the larger of its current value and
+** the number of entries in the Vdbe.apArg[] array required to execute the
+** returned program.
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeTakeOpArray(Vdbe *p, int *pnOp, int *pnMaxArg){
+  VdbeOp *aOp = p->aOp;
+  assert( aOp && !p->db->mallocFailed );
+
+  /* Check that sqlite3VdbeUsesBtree() was not called on this VM */
+  assert( DbMaskAllZero(p->btreeMask) );
+
+  resolveP2Values(p, pnMaxArg);
+  *pnOp = p->nOp;
+  p->aOp = 0;
+  return aOp;
+}
+
+/*
+** Add a whole list of operations to the operation stack.  Return a
+** pointer to the first operation inserted.
+**
+** Non-zero P2 arguments to jump instructions are automatically adjusted
+** so that the jump target is relative to the first operation inserted.
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeAddOpList(
+  Vdbe *p,                     /* Add opcodes to the prepared statement */
+  int nOp,                     /* Number of opcodes to add */
+  VdbeOpList const *aOp,       /* The opcodes to be added */
+  int iLineno                  /* Source-file line number of first opcode */
+){
+  int i;
+  VdbeOp *pOut, *pFirst;
+  assert( nOp>0 );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  if( p->nOp + nOp > p->nOpAlloc && growOpArray(p, nOp) ){
+    return 0;
+  }
+  pFirst = pOut = &p->aOp[p->nOp];
+  for(i=0; i<nOp; i++, aOp++, pOut++){
+    pOut->opcode = aOp->opcode;
+    pOut->p1 = aOp->p1;
+    pOut->p2 = aOp->p2;
+    assert( aOp->p2>=0 );
+    if( (sqlite3OpcodeProperty[aOp->opcode] & OPFLG_JUMP)!=0 && aOp->p2>0 ){
+      pOut->p2 += p->nOp;
+    }
+    pOut->p3 = aOp->p3;
+    pOut->p4type = P4_NOTUSED;
+    pOut->p4.p = 0;
+    pOut->p5 = 0;
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+    pOut->zComment = 0;
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+    pOut->iSrcLine = iLineno+i;
+#else
+    (void)iLineno;
+#endif
+#ifdef SQLITE_DEBUG
+    if( p->db->flags & SQLITE_VdbeAddopTrace ){
+      sqlite3VdbePrintOp(0, i+p->nOp, &p->aOp[i+p->nOp]);
+    }
+#endif
+  }
+  p->nOp += nOp;
+  return pFirst;
+}
+
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+/*
+** Add an entry to the array of counters managed by sqlite3_stmt_scanstatus().
+*/
+SQLITE_PRIVATE void sqlite3VdbeScanStatus(
+  Vdbe *p,                        /* VM to add scanstatus() to */
+  int addrExplain,                /* Address of OP_Explain (or 0) */
+  int addrLoop,                   /* Address of loop counter */
+  int addrVisit,                  /* Address of rows visited counter */
+  LogEst nEst,                    /* Estimated number of output rows */
+  const char *zName               /* Name of table or index being scanned */
+){
+  if( IS_STMT_SCANSTATUS(p->db) ){
+    sqlite3_int64 nByte = (p->nScan+1) * sizeof(ScanStatus);
+    ScanStatus *aNew;
+    aNew = (ScanStatus*)sqlite3DbRealloc(p->db, p->aScan, nByte);
+    if( aNew ){
+      ScanStatus *pNew = &aNew[p->nScan++];
+      memset(pNew, 0, sizeof(ScanStatus));
+      pNew->addrExplain = addrExplain;
+      pNew->addrLoop = addrLoop;
+      pNew->addrVisit = addrVisit;
+      pNew->nEst = nEst;
+      pNew->zName = sqlite3DbStrDup(p->db, zName);
+      p->aScan = aNew;
+    }
+  }
+}
+
+/*
+** Add the range of instructions from addrStart to addrEnd (inclusive) to
+** the set of those corresponding to the sqlite3_stmt_scanstatus() counters
+** associated with the OP_Explain instruction at addrExplain. The
+** sum of the sqlite3Hwtime() values for each of these instructions
+** will be returned for SQLITE_SCANSTAT_NCYCLE requests.
+*/
+SQLITE_PRIVATE void sqlite3VdbeScanStatusRange(
+  Vdbe *p,
+  int addrExplain,
+  int addrStart,
+  int addrEnd
+){
+  if( IS_STMT_SCANSTATUS(p->db) ){
+    ScanStatus *pScan = 0;
+    int ii;
+    for(ii=p->nScan-1; ii>=0; ii--){
+      pScan = &p->aScan[ii];
+      if( pScan->addrExplain==addrExplain ) break;
+      pScan = 0;
+    }
+    if( pScan ){
+      if( addrEnd<0 ) addrEnd = sqlite3VdbeCurrentAddr(p)-1;
+      for(ii=0; ii<ArraySize(pScan->aAddrRange); ii+=2){
+        if( pScan->aAddrRange[ii]==0 ){
+          pScan->aAddrRange[ii] = addrStart;
+          pScan->aAddrRange[ii+1] = addrEnd;
+          break;
+        }
+      }
+    }
+  }
+}
+
+/*
+** Set the addresses for the SQLITE_SCANSTAT_NLOOP and SQLITE_SCANSTAT_NROW
+** counters for the query element associated with the OP_Explain at
+** addrExplain.
+*/
+SQLITE_PRIVATE void sqlite3VdbeScanStatusCounters(
+  Vdbe *p,
+  int addrExplain,
+  int addrLoop,
+  int addrVisit
+){
+  if( IS_STMT_SCANSTATUS(p->db) ){
+    ScanStatus *pScan = 0;
+    int ii;
+    for(ii=p->nScan-1; ii>=0; ii--){
+      pScan = &p->aScan[ii];
+      if( pScan->addrExplain==addrExplain ) break;
+      pScan = 0;
+    }
+    if( pScan ){
+      if( addrLoop>0 ) pScan->addrLoop = addrLoop;
+      if( addrVisit>0 ) pScan->addrVisit = addrVisit;
+    }
+  }
+}
+#endif /* defined(SQLITE_ENABLE_STMT_SCANSTATUS) */
+
+
+/*
+** Change the value of the opcode, or P1, P2, P3, or P5 operands
+** for a specific instruction.
+*/
+SQLITE_PRIVATE void sqlite3VdbeChangeOpcode(Vdbe *p, int addr, u8 iNewOpcode){
+  assert( addr>=0 );
+  sqlite3VdbeGetOp(p,addr)->opcode = iNewOpcode;
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe *p, int addr, int val){
+  assert( addr>=0 );
+  sqlite3VdbeGetOp(p,addr)->p1 = val;
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe *p, int addr, int val){
+  assert( addr>=0 || p->db->mallocFailed );
+  sqlite3VdbeGetOp(p,addr)->p2 = val;
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe *p, int addr, int val){
+  assert( addr>=0 );
+  sqlite3VdbeGetOp(p,addr)->p3 = val;
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe *p, u16 p5){
+  assert( p->nOp>0 || p->db->mallocFailed );
+  if( p->nOp>0 ) p->aOp[p->nOp-1].p5 = p5;
+}
+
+/*
+** If the previous opcode is an OP_Column that delivers results
+** into register iDest, then add the OPFLAG_TYPEOFARG flag to that
+** opcode.
+*/
+SQLITE_PRIVATE void sqlite3VdbeTypeofColumn(Vdbe *p, int iDest){
+  VdbeOp *pOp = sqlite3VdbeGetLastOp(p);
+  if( pOp->p3==iDest && pOp->opcode==OP_Column ){
+    pOp->p5 |= OPFLAG_TYPEOFARG;
+  }
+}
+
+/*
+** Change the P2 operand of instruction addr so that it points to
+** the address of the next instruction to be coded.
+*/
+SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe *p, int addr){
+  sqlite3VdbeChangeP2(p, addr, p->nOp);
+}
+
+/*
+** Change the P2 operand of the jump instruction at addr so that
+** the jump lands on the next opcode.  Or if the jump instruction was
+** the previous opcode (and is thus a no-op) then simply back up
+** the next instruction counter by one slot so that the jump is
+** overwritten by the next inserted opcode.
+**
+** This routine is an optimization of sqlite3VdbeJumpHere() that
+** strives to omit useless byte-code like this:
+**
+**        7   Once 0 8 0
+**        8   ...
+*/
+SQLITE_PRIVATE void sqlite3VdbeJumpHereOrPopInst(Vdbe *p, int addr){
+  if( addr==p->nOp-1 ){
+    assert( p->aOp[addr].opcode==OP_Once
+         || p->aOp[addr].opcode==OP_If
+         || p->aOp[addr].opcode==OP_FkIfZero );
+    assert( p->aOp[addr].p4type==0 );
+#ifdef SQLITE_VDBE_COVERAGE
+    sqlite3VdbeGetLastOp(p)->iSrcLine = 0;  /* Erase VdbeCoverage() macros */
+#endif
+    p->nOp--;
+  }else{
+    sqlite3VdbeChangeP2(p, addr, p->nOp);
+  }
+}
+
+
+/*
+** If the input FuncDef structure is ephemeral, then free it.  If
+** the FuncDef is not ephemeral, then do nothing.
+*/
+static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef){
+  assert( db!=0 );
+  if( (pDef->funcFlags & SQLITE_FUNC_EPHEM)!=0 ){
+    sqlite3DbNNFreeNN(db, pDef);
+  }
+}
+
+/*
+** Delete a P4 value if necessary.
+*/
+static SQLITE_NOINLINE void freeP4Mem(sqlite3 *db, Mem *p){
+  if( p->szMalloc ) sqlite3DbFree(db, p->zMalloc);
+  sqlite3DbNNFreeNN(db, p);
+}
+static SQLITE_NOINLINE void freeP4FuncCtx(sqlite3 *db, sqlite3_context *p){
+  assert( db!=0 );
+  freeEphemeralFunction(db, p->pFunc);
+  sqlite3DbNNFreeNN(db, p);
+}
+static void freeP4(sqlite3 *db, int p4type, void *p4){
+  assert( db );
+  switch( p4type ){
+    case P4_FUNCCTX: {
+      freeP4FuncCtx(db, (sqlite3_context*)p4);
+      break;
+    }
+    case P4_REAL:
+    case P4_INT64:
+    case P4_DYNAMIC:
+    case P4_INTARRAY: {
+      if( p4 ) sqlite3DbNNFreeNN(db, p4);
+      break;
+    }
+    case P4_KEYINFO: {
+      if( db->pnBytesFreed==0 ) sqlite3KeyInfoUnref((KeyInfo*)p4);
+      break;
+    }
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+    case P4_EXPR: {
+      sqlite3ExprDelete(db, (Expr*)p4);
+      break;
+    }
+#endif
+    case P4_FUNCDEF: {
+      freeEphemeralFunction(db, (FuncDef*)p4);
+      break;
+    }
+    case P4_MEM: {
+      if( db->pnBytesFreed==0 ){
+        sqlite3ValueFree((sqlite3_value*)p4);
+      }else{
+        freeP4Mem(db, (Mem*)p4);
+      }
+      break;
+    }
+    case P4_VTAB : {
+      if( db->pnBytesFreed==0 ) sqlite3VtabUnlock((VTable *)p4);
+      break;
+    }
+    case P4_TABLEREF: {
+      if( db->pnBytesFreed==0 ) sqlite3DeleteTable(db, (Table*)p4);
+      break;
+    }
+    case P4_SUBRTNSIG: {
+      SubrtnSig *pSig = (SubrtnSig*)p4;
+      sqlite3DbFree(db, pSig->zAff);
+      sqlite3DbFree(db, pSig);
+      break;
+    }
+  }
+}
+
+/*
+** Free the space allocated for aOp and any p4 values allocated for the
+** opcodes contained within. If aOp is not NULL it is assumed to contain
+** nOp entries.
+*/
+static void vdbeFreeOpArray(sqlite3 *db, Op *aOp, int nOp){
+  assert( nOp>=0 );
+  assert( db!=0 );
+  if( aOp ){
+    Op *pOp = &aOp[nOp-1];
+    while(1){  /* Exit via break */
+      if( pOp->p4type <= P4_FREE_IF_LE ) freeP4(db, pOp->p4type, pOp->p4.p);
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+      sqlite3DbFree(db, pOp->zComment);
+#endif
+      if( pOp==aOp ) break;
+      pOp--;
+    }
+    sqlite3DbNNFreeNN(db, aOp);
+  }
+}
+
+/*
+** Link the SubProgram object passed as the second argument into the linked
+** list at Vdbe.pSubProgram. This list is used to delete all sub-program
+** objects when the VM is no longer required.
+*/
+SQLITE_PRIVATE void sqlite3VdbeLinkSubProgram(Vdbe *pVdbe, SubProgram *p){
+  p->pNext = pVdbe->pProgram;
+  pVdbe->pProgram = p;
+}
+
+/*
+** Return true if the given Vdbe has any SubPrograms.
+*/
+SQLITE_PRIVATE int sqlite3VdbeHasSubProgram(Vdbe *pVdbe){
+  return pVdbe->pProgram!=0;
+}
+
+/*
+** Change the opcode at addr into OP_Noop
+*/
+SQLITE_PRIVATE int sqlite3VdbeChangeToNoop(Vdbe *p, int addr){
+  VdbeOp *pOp;
+  if( p->db->mallocFailed ) return 0;
+  assert( addr>=0 && addr<p->nOp );
+  pOp = &p->aOp[addr];
+  freeP4(p->db, pOp->p4type, pOp->p4.p);
+  pOp->p4type = P4_NOTUSED;
+  pOp->p4.z = 0;
+  pOp->opcode = OP_Noop;
+  return 1;
+}
+
+/*
+** If the last opcode is "op" and it is not a jump destination,
+** then remove it.  Return true if and only if an opcode was removed.
+*/
+SQLITE_PRIVATE int sqlite3VdbeDeletePriorOpcode(Vdbe *p, u8 op){
+  if( p->nOp>0 && p->aOp[p->nOp-1].opcode==op ){
+    return sqlite3VdbeChangeToNoop(p, p->nOp-1);
+  }else{
+    return 0;
+  }
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Generate an OP_ReleaseReg opcode to indicate that a range of
+** registers, except any identified by mask, are no longer in use.
+*/
+SQLITE_PRIVATE void sqlite3VdbeReleaseRegisters(
+  Parse *pParse,       /* Parsing context */
+  int iFirst,          /* Index of first register to be released */
+  int N,               /* Number of registers to release */
+  u32 mask,            /* Mask of registers to NOT release */
+  int bUndefine        /* If true, mark registers as undefined */
+){
+  if( N==0 || OptimizationDisabled(pParse->db, SQLITE_ReleaseReg) ) return;
+  assert( pParse->pVdbe );
+  assert( iFirst>=1 );
+  assert( iFirst+N-1<=pParse->nMem );
+  if( N<=31 && mask!=0 ){
+    while( N>0 && (mask&1)!=0 ){
+      mask >>= 1;
+      iFirst++;
+      N--;
+    }
+    while( N>0 && N<=32 && (mask & MASKBIT32(N-1))!=0 ){
+      mask &= ~MASKBIT32(N-1);
+      N--;
+    }
+  }
+  if( N>0 ){
+    sqlite3VdbeAddOp3(pParse->pVdbe, OP_ReleaseReg, iFirst, N, *(int*)&mask);
+    if( bUndefine ) sqlite3VdbeChangeP5(pParse->pVdbe, 1);
+  }
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** Change the value of the P4 operand for a specific instruction.
+** This routine is useful when a large program is loaded from a
+** static array using sqlite3VdbeAddOpList but we want to make a
+** few minor changes to the program.
+**
+** If n>=0 then the P4 operand is dynamic, meaning that a copy of
+** the string is made into memory obtained from sqlite3_malloc().
+** A value of n==0 means copy bytes of zP4 up to and including the
+** first null byte.  If n>0 then copy n+1 bytes of zP4.
+**
+** Other values of n (P4_STATIC, P4_COLLSEQ etc.) indicate that zP4 points
+** to a string or structure that is guaranteed to exist for the lifetime of
+** the Vdbe. In these cases we can just copy the pointer.
+**
+** If addr<0 then change P4 on the most recently inserted instruction.
+*/
+static void SQLITE_NOINLINE vdbeChangeP4Full(
+  Vdbe *p,
+  Op *pOp,
+  const char *zP4,
+  int n
+){
+  if( pOp->p4type ){
+    assert( pOp->p4type > P4_FREE_IF_LE );
+    pOp->p4type = 0;
+    pOp->p4.p = 0;
+  }
+  if( n<0 ){
+    sqlite3VdbeChangeP4(p, (int)(pOp - p->aOp), zP4, n);
+  }else{
+    if( n==0 ) n = sqlite3Strlen30(zP4);
+    pOp->p4.z = sqlite3DbStrNDup(p->db, zP4, n);
+    pOp->p4type = P4_DYNAMIC;
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int n){
+  Op *pOp;
+  sqlite3 *db;
+  assert( p!=0 );
+  db = p->db;
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  assert( p->aOp!=0 || db->mallocFailed );
+  if( db->mallocFailed ){
+    if( n!=P4_VTAB ) freeP4(db, n, (void*)*(char**)&zP4);
+    return;
+  }
+  assert( p->nOp>0 );
+  assert( addr<p->nOp );
+  if( addr<0 ){
+    addr = p->nOp - 1;
+  }
+  pOp = &p->aOp[addr];
+  if( n>=0 || pOp->p4type ){
+    vdbeChangeP4Full(p, pOp, zP4, n);
+    return;
+  }
+  if( n==P4_INT32 ){
+    /* Note: this cast is safe, because the origin data point was an int
+    ** that was cast to a (const char *). */
+    pOp->p4.i = SQLITE_PTR_TO_INT(zP4);
+    pOp->p4type = P4_INT32;
+  }else if( zP4!=0 ){
+    assert( n<0 );
+    pOp->p4.p = (void*)zP4;
+    pOp->p4type = (signed char)n;
+    if( n==P4_VTAB ) sqlite3VtabLock((VTable*)zP4);
+  }
+}
+
+/*
+** Change the P4 operand of the most recently coded instruction
+** to the value defined by the arguments.  This is a high-speed
+** version of sqlite3VdbeChangeP4().
+**
+** The P4 operand must not have been previously defined.  And the new
+** P4 must not be P4_INT32.  Use sqlite3VdbeChangeP4() in either of
+** those cases.
+*/
+SQLITE_PRIVATE void sqlite3VdbeAppendP4(Vdbe *p, void *pP4, int n){
+  VdbeOp *pOp;
+  assert( n!=P4_INT32 && n!=P4_VTAB );
+  assert( n<=0 );
+  if( p->db->mallocFailed ){
+    freeP4(p->db, n, pP4);
+  }else{
+    assert( pP4!=0 || n==P4_DYNAMIC );
+    assert( p->nOp>0 );
+    pOp = &p->aOp[p->nOp-1];
+    assert( pOp->p4type==P4_NOTUSED );
+    pOp->p4type = n;
+    pOp->p4.p = pP4;
+  }
+}
+
+/*
+** Set the P4 on the most recently added opcode to the KeyInfo for the
+** index given.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetP4KeyInfo(Parse *pParse, Index *pIdx){
+  Vdbe *v = pParse->pVdbe;
+  KeyInfo *pKeyInfo;
+  assert( v!=0 );
+  assert( pIdx!=0 );
+  pKeyInfo = sqlite3KeyInfoOfIndex(pParse, pIdx);
+  if( pKeyInfo ) sqlite3VdbeAppendP4(v, pKeyInfo, P4_KEYINFO);
+}
+
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+/*
+** Change the comment on the most recently coded instruction.  Or
+** insert a No-op and add the comment to that new instruction.  This
+** makes the code easier to read during debugging.  None of this happens
+** in a production build.
+*/
+static void vdbeVComment(Vdbe *p, const char *zFormat, va_list ap){
+  assert( p->nOp>0 || p->aOp==0 );
+  assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->pParse->nErr>0 );
+  if( p->nOp ){
+    assert( p->aOp );
+    sqlite3DbFree(p->db, p->aOp[p->nOp-1].zComment);
+    p->aOp[p->nOp-1].zComment = sqlite3VMPrintf(p->db, zFormat, ap);
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
+  va_list ap;
+  if( p ){
+    va_start(ap, zFormat);
+    vdbeVComment(p, zFormat, ap);
+    va_end(ap);
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeNoopComment(Vdbe *p, const char *zFormat, ...){
+  va_list ap;
+  if( p ){
+    sqlite3VdbeAddOp0(p, OP_Noop);
+    va_start(ap, zFormat);
+    vdbeVComment(p, zFormat, ap);
+    va_end(ap);
+  }
+}
+#endif  /* NDEBUG */
+
+#ifdef SQLITE_VDBE_COVERAGE
+/*
+** Set the value if the iSrcLine field for the previously coded instruction.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetLineNumber(Vdbe *v, int iLine){
+  sqlite3VdbeGetLastOp(v)->iSrcLine = iLine;
+}
+#endif /* SQLITE_VDBE_COVERAGE */
+
+/*
+** Return the opcode for a given address.  The address must be non-negative.
+** See sqlite3VdbeGetLastOp() to get the most recently added opcode.
+**
+** If a memory allocation error has occurred prior to the calling of this
+** routine, then a pointer to a dummy VdbeOp will be returned.  That opcode
+** is readable but not writable, though it is cast to a writable value.
+** The return of a dummy opcode allows the call to continue functioning
+** after an OOM fault without having to check to see if the return from
+** this routine is a valid pointer.  But because the dummy.opcode is 0,
+** dummy will never be written to.  This is verified by code inspection and
+** by running with Valgrind.
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
+  /* C89 specifies that the constant "dummy" will be initialized to all
+  ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
+  static VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
+  if( p->db->mallocFailed ){
+    return (VdbeOp*)&dummy;
+  }else{
+    return &p->aOp[addr];
+  }
+}
+
+/* Return the most recently added opcode
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetLastOp(Vdbe *p){
+  return sqlite3VdbeGetOp(p, p->nOp - 1);
+}
+
+#if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS)
+/*
+** Return an integer value for one of the parameters to the opcode pOp
+** determined by character c.
+*/
+static int translateP(char c, const Op *pOp){
+  if( c=='1' ) return pOp->p1;
+  if( c=='2' ) return pOp->p2;
+  if( c=='3' ) return pOp->p3;
+  if( c=='4' ) return pOp->p4.i;
+  return pOp->p5;
+}
+
+/*
+** Compute a string for the "comment" field of a VDBE opcode listing.
+**
+** The Synopsis: field in comments in the vdbe.c source file gets converted
+** to an extra string that is appended to the sqlite3OpcodeName().  In the
+** absence of other comments, this synopsis becomes the comment on the opcode.
+** Some translation occurs:
+**
+**       "PX"      ->  "r[X]"
+**       "PX@PY"   ->  "r[X..X+Y-1]"  or "r[x]" if y is 0 or 1
+**       "PX@PY+1" ->  "r[X..X+Y]"    or "r[x]" if y is 0
+**       "PY..PY"  ->  "r[X..Y]"      or "r[x]" if y<=x
+*/
+SQLITE_PRIVATE char *sqlite3VdbeDisplayComment(
+  sqlite3 *db,       /* Optional - Oom error reporting only */
+  const Op *pOp,     /* The opcode to be commented */
+  const char *zP4    /* Previously obtained value for P4 */
+){
+  const char *zOpName;
+  const char *zSynopsis;
+  int nOpName;
+  int ii;
+  char zAlt[50];
+  StrAccum x;
+
+  sqlite3StrAccumInit(&x, 0, 0, 0, SQLITE_MAX_LENGTH);
+  zOpName = sqlite3OpcodeName(pOp->opcode);
+  nOpName = sqlite3Strlen30(zOpName);
+  if( zOpName[nOpName+1] ){
+    int seenCom = 0;
+    char c;
+    zSynopsis = zOpName + nOpName + 1;
+    if( strncmp(zSynopsis,"IF ",3)==0 ){
+      sqlite3_snprintf(sizeof(zAlt), zAlt, "if %s goto P2", zSynopsis+3);
+      zSynopsis = zAlt;
+    }
+    for(ii=0; (c = zSynopsis[ii])!=0; ii++){
+      if( c=='P' ){
+        c = zSynopsis[++ii];
+        if( c=='4' ){
+          sqlite3_str_appendall(&x, zP4);
+        }else if( c=='X' ){
+          if( pOp->zComment && pOp->zComment[0] ){
+            sqlite3_str_appendall(&x, pOp->zComment);
+            seenCom = 1;
+            break;
+          }
+        }else{
+          int v1 = translateP(c, pOp);
+          int v2;
+          if( strncmp(zSynopsis+ii+1, "@P", 2)==0 ){
+            ii += 3;
+            v2 = translateP(zSynopsis[ii], pOp);
+            if( strncmp(zSynopsis+ii+1,"+1",2)==0 ){
+              ii += 2;
+              v2++;
+            }
+            if( v2<2 ){
+              sqlite3_str_appendf(&x, "%d", v1);
+            }else{
+              sqlite3_str_appendf(&x, "%d..%d", v1, v1+v2-1);
+            }
+          }else if( strncmp(zSynopsis+ii+1, "@NP", 3)==0 ){
+            sqlite3_context *pCtx = pOp->p4.pCtx;
+            if( pOp->p4type!=P4_FUNCCTX || pCtx->argc==1 ){
+              sqlite3_str_appendf(&x, "%d", v1);
+            }else if( pCtx->argc>1 ){
+              sqlite3_str_appendf(&x, "%d..%d", v1, v1+pCtx->argc-1);
+            }else if( x.accError==0 ){
+              assert( x.nChar>2 );
+              x.nChar -= 2;
+              ii++;
+            }
+            ii += 3;
+          }else{
+            sqlite3_str_appendf(&x, "%d", v1);
+            if( strncmp(zSynopsis+ii+1, "..P3", 4)==0 && pOp->p3==0 ){
+              ii += 4;
+            }
+          }
+        }
+      }else{
+        sqlite3_str_appendchar(&x, 1, c);
+      }
+    }
+    if( !seenCom && pOp->zComment ){
+      sqlite3_str_appendf(&x, "; %s", pOp->zComment);
+    }
+  }else if( pOp->zComment ){
+    sqlite3_str_appendall(&x, pOp->zComment);
+  }
+  if( (x.accError & SQLITE_NOMEM)!=0 && db!=0 ){
+    sqlite3OomFault(db);
+  }
+  return sqlite3StrAccumFinish(&x);
+}
+#endif /* SQLITE_ENABLE_EXPLAIN_COMMENTS */
+
+#if VDBE_DISPLAY_P4 && defined(SQLITE_ENABLE_CURSOR_HINTS)
+/*
+** Translate the P4.pExpr value for an OP_CursorHint opcode into text
+** that can be displayed in the P4 column of EXPLAIN output.
+*/
+static void displayP4Expr(StrAccum *p, Expr *pExpr){
+  const char *zOp = 0;
+  switch( pExpr->op ){
+    case TK_STRING:
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3_str_appendf(p, "%Q", pExpr->u.zToken);
+      break;
+    case TK_INTEGER:
+      sqlite3_str_appendf(p, "%d", pExpr->u.iValue);
+      break;
+    case TK_NULL:
+      sqlite3_str_appendf(p, "NULL");
+      break;
+    case TK_REGISTER: {
+      sqlite3_str_appendf(p, "r[%d]", pExpr->iTable);
+      break;
+    }
+    case TK_COLUMN: {
+      if( pExpr->iColumn<0 ){
+        sqlite3_str_appendf(p, "rowid");
+      }else{
+        sqlite3_str_appendf(p, "c%d", (int)pExpr->iColumn);
+      }
+      break;
+    }
+    case TK_LT:      zOp = "LT";      break;
+    case TK_LE:      zOp = "LE";      break;
+    case TK_GT:      zOp = "GT";      break;
+    case TK_GE:      zOp = "GE";      break;
+    case TK_NE:      zOp = "NE";      break;
+    case TK_EQ:      zOp = "EQ";      break;
+    case TK_IS:      zOp = "IS";      break;
+    case TK_ISNOT:   zOp = "ISNOT";   break;
+    case TK_AND:     zOp = "AND";     break;
+    case TK_OR:      zOp = "OR";      break;
+    case TK_PLUS:    zOp = "ADD";     break;
+    case TK_STAR:    zOp = "MUL";     break;
+    case TK_MINUS:   zOp = "SUB";     break;
+    case TK_REM:     zOp = "REM";     break;
+    case TK_BITAND:  zOp = "BITAND";  break;
+    case TK_BITOR:   zOp = "BITOR";   break;
+    case TK_SLASH:   zOp = "DIV";     break;
+    case TK_LSHIFT:  zOp = "LSHIFT";  break;
+    case TK_RSHIFT:  zOp = "RSHIFT";  break;
+    case TK_CONCAT:  zOp = "CONCAT";  break;
+    case TK_UMINUS:  zOp = "MINUS";   break;
+    case TK_UPLUS:   zOp = "PLUS";    break;
+    case TK_BITNOT:  zOp = "BITNOT";  break;
+    case TK_NOT:     zOp = "NOT";     break;
+    case TK_ISNULL:  zOp = "ISNULL";  break;
+    case TK_NOTNULL: zOp = "NOTNULL"; break;
+
+    default:
+      sqlite3_str_appendf(p, "%s", "expr");
+      break;
+  }
+
+  if( zOp ){
+    sqlite3_str_appendf(p, "%s(", zOp);
+    displayP4Expr(p, pExpr->pLeft);
+    if( pExpr->pRight ){
+      sqlite3_str_append(p, ",", 1);
+      displayP4Expr(p, pExpr->pRight);
+    }
+    sqlite3_str_append(p, ")", 1);
+  }
+}
+#endif /* VDBE_DISPLAY_P4 && defined(SQLITE_ENABLE_CURSOR_HINTS) */
+
+
+#if VDBE_DISPLAY_P4
+/*
+** Compute a string that describes the P4 parameter for an opcode.
+** Use zTemp for any required temporary buffer space.
+*/
+SQLITE_PRIVATE char *sqlite3VdbeDisplayP4(sqlite3 *db, Op *pOp){
+  char *zP4 = 0;
+  StrAccum x;
+
+  sqlite3StrAccumInit(&x, 0, 0, 0, SQLITE_MAX_LENGTH);
+  switch( pOp->p4type ){
+    case P4_KEYINFO: {
+      int j;
+      KeyInfo *pKeyInfo = pOp->p4.pKeyInfo;
+      assert( pKeyInfo->aSortFlags!=0 );
+      sqlite3_str_appendf(&x, "k(%d", pKeyInfo->nKeyField);
+      for(j=0; j<pKeyInfo->nKeyField; j++){
+        CollSeq *pColl = pKeyInfo->aColl[j];
+        const char *zColl = pColl ? pColl->zName : "";
+        if( strcmp(zColl, "BINARY")==0 ) zColl = "B";
+        sqlite3_str_appendf(&x, ",%s%s%s",
+               (pKeyInfo->aSortFlags[j] & KEYINFO_ORDER_DESC) ? "-" : "",
+               (pKeyInfo->aSortFlags[j] & KEYINFO_ORDER_BIGNULL)? "N." : "",
+               zColl);
+      }
+      sqlite3_str_append(&x, ")", 1);
+      break;
+    }
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+    case P4_EXPR: {
+      displayP4Expr(&x, pOp->p4.pExpr);
+      break;
+    }
+#endif
+    case P4_COLLSEQ: {
+      static const char *const encnames[] = {"?", "8", "16LE", "16BE"};
+      CollSeq *pColl = pOp->p4.pColl;
+      assert( pColl->enc<4 );
+      sqlite3_str_appendf(&x, "%.18s-%s", pColl->zName,
+                          encnames[pColl->enc]);
+      break;
+    }
+    case P4_FUNCDEF: {
+      FuncDef *pDef = pOp->p4.pFunc;
+      sqlite3_str_appendf(&x, "%s(%d)", pDef->zName, pDef->nArg);
+      break;
+    }
+    case P4_FUNCCTX: {
+      FuncDef *pDef = pOp->p4.pCtx->pFunc;
+      sqlite3_str_appendf(&x, "%s(%d)", pDef->zName, pDef->nArg);
+      break;
+    }
+    case P4_INT64: {
+      sqlite3_str_appendf(&x, "%lld", *pOp->p4.pI64);
+      break;
+    }
+    case P4_INT32: {
+      sqlite3_str_appendf(&x, "%d", pOp->p4.i);
+      break;
+    }
+    case P4_REAL: {
+      sqlite3_str_appendf(&x, "%.16g", *pOp->p4.pReal);
+      break;
+    }
+    case P4_MEM: {
+      Mem *pMem = pOp->p4.pMem;
+      if( pMem->flags & MEM_Str ){
+        zP4 = pMem->z;
+      }else if( pMem->flags & (MEM_Int|MEM_IntReal) ){
+        sqlite3_str_appendf(&x, "%lld", pMem->u.i);
+      }else if( pMem->flags & MEM_Real ){
+        sqlite3_str_appendf(&x, "%.16g", pMem->u.r);
+      }else if( pMem->flags & MEM_Null ){
+        zP4 = "NULL";
+      }else{
+        assert( pMem->flags & MEM_Blob );
+        zP4 = "(blob)";
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    case P4_VTAB: {
+      sqlite3_vtab *pVtab = pOp->p4.pVtab->pVtab;
+      sqlite3_str_appendf(&x, "vtab:%p", pVtab);
+      break;
+    }
+#endif
+    case P4_INTARRAY: {
+      u32 i;
+      u32 *ai = pOp->p4.ai;
+      u32 n = ai[0];   /* The first element of an INTARRAY is always the
+                       ** count of the number of elements to follow */
+      for(i=1; i<=n; i++){
+        sqlite3_str_appendf(&x, "%c%u", (i==1 ? '[' : ','), ai[i]);
+      }
+      sqlite3_str_append(&x, "]", 1);
+      break;
+    }
+    case P4_SUBPROGRAM: {
+      zP4 = "program";
+      break;
+    }
+    case P4_TABLE: {
+      zP4 = pOp->p4.pTab->zName;
+      break;
+    }
+    case P4_SUBRTNSIG: {
+      SubrtnSig *pSig = pOp->p4.pSubrtnSig;
+      sqlite3_str_appendf(&x, "subrtnsig:%d,%s", pSig->selId, pSig->zAff);
+      break;
+    }
+    default: {
+      zP4 = pOp->p4.z;
+    }
+  }
+  if( zP4 ) sqlite3_str_appendall(&x, zP4);
+  if( (x.accError & SQLITE_NOMEM)!=0 ){
+    sqlite3OomFault(db);
+  }
+  return sqlite3StrAccumFinish(&x);
+}
+#endif /* VDBE_DISPLAY_P4 */
+
+/*
+** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
+**
+** The prepared statements need to know in advance the complete set of
+** attached databases that will be use.  A mask of these databases
+** is maintained in p->btreeMask.  The p->lockMask value is the subset of
+** p->btreeMask of databases that will require a lock.
+*/
+SQLITE_PRIVATE void sqlite3VdbeUsesBtree(Vdbe *p, int i){
+  assert( i>=0 && i<p->db->nDb && i<(int)sizeof(yDbMask)*8 );
+  assert( i<(int)sizeof(p->btreeMask)*8 );
+  DbMaskSet(p->btreeMask, i);
+  if( i!=1 && sqlite3BtreeSharable(p->db->aDb[i].pBt) ){
+    DbMaskSet(p->lockMask, i);
+  }
+}
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE)
+/*
+** If SQLite is compiled to support shared-cache mode and to be threadsafe,
+** this routine obtains the mutex associated with each BtShared structure
+** that may be accessed by the VM passed as an argument. In doing so it also
+** sets the BtShared.db member of each of the BtShared structures, ensuring
+** that the correct busy-handler callback is invoked if required.
+**
+** If SQLite is not threadsafe but does support shared-cache mode, then
+** sqlite3BtreeEnter() is invoked to set the BtShared.db variables
+** of all of BtShared structures accessible via the database handle
+** associated with the VM.
+**
+** If SQLite is not threadsafe and does not support shared-cache mode, this
+** function is a no-op.
+**
+** The p->btreeMask field is a bitmask of all btrees that the prepared
+** statement p will ever use.  Let N be the number of bits in p->btreeMask
+** corresponding to btrees that use shared cache.  Then the runtime of
+** this routine is N*N.  But as N is rarely more than 1, this should not
+** be a problem.
+*/
+SQLITE_PRIVATE void sqlite3VdbeEnter(Vdbe *p){
+  int i;
+  sqlite3 *db;
+  Db *aDb;
+  int nDb;
+  if( DbMaskAllZero(p->lockMask) ) return;  /* The common case */
+  db = p->db;
+  aDb = db->aDb;
+  nDb = db->nDb;
+  for(i=0; i<nDb; i++){
+    if( i!=1 && DbMaskTest(p->lockMask,i) && ALWAYS(aDb[i].pBt!=0) ){
+      sqlite3BtreeEnter(aDb[i].pBt);
+    }
+  }
+}
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0
+/*
+** Unlock all of the btrees previously locked by a call to sqlite3VdbeEnter().
+*/
+static SQLITE_NOINLINE void vdbeLeave(Vdbe *p){
+  int i;
+  sqlite3 *db;
+  Db *aDb;
+  int nDb;
+  db = p->db;
+  aDb = db->aDb;
+  nDb = db->nDb;
+  for(i=0; i<nDb; i++){
+    if( i!=1 && DbMaskTest(p->lockMask,i) && ALWAYS(aDb[i].pBt!=0) ){
+      sqlite3BtreeLeave(aDb[i].pBt);
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeLeave(Vdbe *p){
+  if( DbMaskAllZero(p->lockMask) ) return;  /* The common case */
+  vdbeLeave(p);
+}
+#endif
+
+#if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+/*
+** Print a single opcode.  This routine is used for debugging only.
+*/
+SQLITE_PRIVATE void sqlite3VdbePrintOp(FILE *pOut, int pc, VdbeOp *pOp){
+  char *zP4;
+  char *zCom;
+  sqlite3 dummyDb;
+  static const char *zFormat1 = "%4d %-13s %4d %4d %4d %-13s %.2X %s\n";
+  if( pOut==0 ) pOut = stdout;
+  sqlite3BeginBenignMalloc();
+  dummyDb.mallocFailed = 1;
+  zP4 = sqlite3VdbeDisplayP4(&dummyDb, pOp);
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  zCom = sqlite3VdbeDisplayComment(0, pOp, zP4);
+#else
+  zCom = 0;
+#endif
+  /* NB:  The sqlite3OpcodeName() function is implemented by code created
+  ** by the mkopcodeh.awk and mkopcodec.awk scripts which extract the
+  ** information from the vdbe.c source text */
+  fprintf(pOut, zFormat1, pc,
+      sqlite3OpcodeName(pOp->opcode), pOp->p1, pOp->p2, pOp->p3,
+      zP4 ? zP4 : "", pOp->p5,
+      zCom ? zCom : ""
+  );
+  fflush(pOut);
+  sqlite3_free(zP4);
+  sqlite3_free(zCom);
+  sqlite3EndBenignMalloc();
+}
+#endif
+
+/*
+** Initialize an array of N Mem element.
+**
+** This is a high-runner, so only those fields that really do need to
+** be initialized are set.  The Mem structure is organized so that
+** the fields that get initialized are nearby and hopefully on the same
+** cache line.
+**
+**    Mem.flags = flags
+**    Mem.db = db
+**    Mem.szMalloc = 0
+**
+** All other fields of Mem can safely remain uninitialized for now.  They
+** will be initialized before use.
+*/
+static void initMemArray(Mem *p, int N, sqlite3 *db, u16 flags){
+  assert( db!=0 );
+  if( N>0 ){
+    do{
+      p->flags = flags;
+      p->db = db;
+      p->szMalloc = 0;
+#ifdef SQLITE_DEBUG
+      p->pScopyFrom = 0;
+      p->bScopy = 0;
+#endif
+      p++;
+    }while( (--N)>0 );
+  }
+}
+
+/*
+** Release auxiliary memory held in an array of N Mem elements.
+**
+** After this routine returns, all Mem elements in the array will still
+** be valid.  Those Mem elements that were not holding auxiliary resources
+** will be unchanged.  Mem elements which had something freed will be
+** set to MEM_Undefined.
+*/
+static void releaseMemArray(Mem *p, int N){
+  if( p && N ){
+    Mem *pEnd = &p[N];
+    sqlite3 *db = p->db;
+    assert( db!=0 );
+    if( db->pnBytesFreed ){
+      do{
+        if( p->szMalloc ) sqlite3DbFree(db, p->zMalloc);
+      }while( (++p)<pEnd );
+      return;
+    }
+    do{
+      assert( (&p[1])==pEnd || p[0].db==p[1].db );
+      assert( sqlite3VdbeCheckMemInvariants(p) );
+
+      /* This block is really an inlined version of sqlite3VdbeMemRelease()
+      ** that takes advantage of the fact that the memory cell value is
+      ** being set to NULL after releasing any dynamic resources.
+      **
+      ** The justification for duplicating code is that according to
+      ** callgrind, this causes a certain test case to hit the CPU 4.7
+      ** percent less (x86 linux, gcc version 4.1.2, -O6) than if
+      ** sqlite3MemRelease() were called from here. With -O2, this jumps
+      ** to 6.6 percent. The test case is inserting 1000 rows into a table
+      ** with no indexes using a single prepared INSERT statement, bind()
+      ** and reset(). Inserts are grouped into a transaction.
+      */
+      testcase( p->flags & MEM_Agg );
+      testcase( p->flags & MEM_Dyn );
+      if( p->flags&(MEM_Agg|MEM_Dyn) ){
+        testcase( (p->flags & MEM_Dyn)!=0 && p->xDel==sqlite3VdbeFrameMemDel );
+        sqlite3VdbeMemRelease(p);
+        p->flags = MEM_Undefined;
+      }else if( p->szMalloc ){
+        sqlite3DbNNFreeNN(db, p->zMalloc);
+        p->szMalloc = 0;
+        p->flags = MEM_Undefined;
+      }
+#ifdef SQLITE_DEBUG
+      else{
+        p->flags = MEM_Undefined;
+      }
+#endif
+    }while( (++p)<pEnd );
+  }
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Verify that pFrame is a valid VdbeFrame pointer.  Return true if it is
+** and false if something is wrong.
+**
+** This routine is intended for use inside of assert() statements only.
+*/
+SQLITE_PRIVATE int sqlite3VdbeFrameIsValid(VdbeFrame *pFrame){
+  if( pFrame->iFrameMagic!=SQLITE_FRAME_MAGIC ) return 0;
+  return 1;
+}
+#endif
+
+
+/*
+** This is a destructor on a Mem object (which is really an sqlite3_value)
+** that deletes the Frame object that is attached to it as a blob.
+**
+** This routine does not delete the Frame right away.  It merely adds the
+** frame to a list of frames to be deleted when the Vdbe halts.
+*/
+SQLITE_PRIVATE void sqlite3VdbeFrameMemDel(void *pArg){
+  VdbeFrame *pFrame = (VdbeFrame*)pArg;
+  assert( sqlite3VdbeFrameIsValid(pFrame) );
+  pFrame->pParent = pFrame->v->pDelFrame;
+  pFrame->v->pDelFrame = pFrame;
+}
+
+#if defined(SQLITE_ENABLE_BYTECODE_VTAB) || !defined(SQLITE_OMIT_EXPLAIN)
+/*
+** Locate the next opcode to be displayed in EXPLAIN or EXPLAIN
+** QUERY PLAN output.
+**
+** Return SQLITE_ROW on success.  Return SQLITE_DONE if there are no
+** more opcodes to be displayed.
+*/
+SQLITE_PRIVATE int sqlite3VdbeNextOpcode(
+  Vdbe *p,         /* The statement being explained */
+  Mem *pSub,       /* Storage for keeping track of subprogram nesting */
+  int eMode,       /* 0: normal.  1: EQP.  2:  TablesUsed */
+  int *piPc,       /* IN/OUT: Current rowid.  Overwritten with next rowid */
+  int *piAddr,     /* OUT: Write index into (*paOp)[] here */
+  Op **paOp        /* OUT: Write the opcode array here */
+){
+  int nRow;                            /* Stop when row count reaches this */
+  int nSub = 0;                        /* Number of sub-vdbes seen so far */
+  SubProgram **apSub = 0;              /* Array of sub-vdbes */
+  int i;                               /* Next instruction address */
+  int rc = SQLITE_OK;                  /* Result code */
+  Op *aOp = 0;                         /* Opcode array */
+  int iPc;                             /* Rowid.  Copy of value in *piPc */
+
+  /* When the number of output rows reaches nRow, that means the
+  ** listing has finished and sqlite3_step() should return SQLITE_DONE.
+  ** nRow is the sum of the number of rows in the main program, plus
+  ** the sum of the number of rows in all trigger subprograms encountered
+  ** so far.  The nRow value will increase as new trigger subprograms are
+  ** encountered, but p->pc will eventually catch up to nRow.
+  */
+  nRow = p->nOp;
+  if( pSub!=0 ){
+    if( pSub->flags&MEM_Blob ){
+      /* pSub is initiallly NULL.  It is initialized to a BLOB by
+      ** the P4_SUBPROGRAM processing logic below */
+      nSub = pSub->n/sizeof(Vdbe*);
+      apSub = (SubProgram **)pSub->z;
+    }
+    for(i=0; i<nSub; i++){
+      nRow += apSub[i]->nOp;
+    }
+  }
+  iPc = *piPc;
+  while(1){  /* Loop exits via break */
+    i = iPc++;
+    if( i>=nRow ){
+      p->rc = SQLITE_OK;
+      rc = SQLITE_DONE;
+      break;
+    }
+    if( i<p->nOp ){
+      /* The rowid is small enough that we are still in the
+      ** main program. */
+      aOp = p->aOp;
+    }else{
+      /* We are currently listing subprograms.  Figure out which one and
+      ** pick up the appropriate opcode. */
+      int j;
+      i -= p->nOp;
+      assert( apSub!=0 );
+      assert( nSub>0 );
+      for(j=0; i>=apSub[j]->nOp; j++){
+        i -= apSub[j]->nOp;
+        assert( i<apSub[j]->nOp || j+1<nSub );
+      }
+      aOp = apSub[j]->aOp;
+    }
+
+    /* When an OP_Program opcode is encounter (the only opcode that has
+    ** a P4_SUBPROGRAM argument), expand the size of the array of subprograms
+    ** kept in p->aMem[9].z to hold the new program - assuming this subprogram
+    ** has not already been seen.
+    */
+    if( pSub!=0 && aOp[i].p4type==P4_SUBPROGRAM ){
+      int nByte = (nSub+1)*sizeof(SubProgram*);
+      int j;
+      for(j=0; j<nSub; j++){
+        if( apSub[j]==aOp[i].p4.pProgram ) break;
+      }
+      if( j==nSub ){
+        p->rc = sqlite3VdbeMemGrow(pSub, nByte, nSub!=0);
+        if( p->rc!=SQLITE_OK ){
+          rc = SQLITE_ERROR;
+          break;
+        }
+        apSub = (SubProgram **)pSub->z;
+        apSub[nSub++] = aOp[i].p4.pProgram;
+        MemSetTypeFlag(pSub, MEM_Blob);
+        pSub->n = nSub*sizeof(SubProgram*);
+        nRow += aOp[i].p4.pProgram->nOp;
+      }
+    }
+    if( eMode==0 ) break;
+#ifdef SQLITE_ENABLE_BYTECODE_VTAB
+    if( eMode==2 ){
+      Op *pOp = aOp + i;
+      if( pOp->opcode==OP_OpenRead ) break;
+      if( pOp->opcode==OP_OpenWrite && (pOp->p5 & OPFLAG_P2ISREG)==0 ) break;
+      if( pOp->opcode==OP_ReopenIdx ) break;
+    }else
+#endif
+    {
+      assert( eMode==1 );
+      if( aOp[i].opcode==OP_Explain ) break;
+      if( aOp[i].opcode==OP_Init && iPc>1 ) break;
+    }
+  }
+  *piPc = iPc;
+  *piAddr = i;
+  *paOp = aOp;
+  return rc;
+}
+#endif /* SQLITE_ENABLE_BYTECODE_VTAB || !SQLITE_OMIT_EXPLAIN */
+
+
+/*
+** Delete a VdbeFrame object and its contents. VdbeFrame objects are
+** allocated by the OP_Program opcode in sqlite3VdbeExec().
+*/
+SQLITE_PRIVATE void sqlite3VdbeFrameDelete(VdbeFrame *p){
+  int i;
+  Mem *aMem = VdbeFrameMem(p);
+  VdbeCursor **apCsr = (VdbeCursor **)&aMem[p->nChildMem];
+  assert( sqlite3VdbeFrameIsValid(p) );
+  for(i=0; i<p->nChildCsr; i++){
+    if( apCsr[i] ) sqlite3VdbeFreeCursorNN(p->v, apCsr[i]);
+  }
+  releaseMemArray(aMem, p->nChildMem);
+  sqlite3VdbeDeleteAuxData(p->v->db, &p->pAuxData, -1, 0);
+  sqlite3DbFree(p->v->db, p);
+}
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Give a listing of the program in the virtual machine.
+**
+** The interface is the same as sqlite3VdbeExec().  But instead of
+** running the code, it invokes the callback once for each instruction.
+** This feature is used to implement "EXPLAIN".
+**
+** When p->explain==1, each instruction is listed.  When
+** p->explain==2, only OP_Explain instructions are listed and these
+** are shown in a different format.  p->explain==2 is used to implement
+** EXPLAIN QUERY PLAN.
+** 2018-04-24:  In p->explain==2 mode, the OP_Init opcodes of triggers
+** are also shown, so that the boundaries between the main program and
+** each trigger are clear.
+**
+** When p->explain==1, first the main program is listed, then each of
+** the trigger subprograms are listed one by one.
+*/
+SQLITE_PRIVATE int sqlite3VdbeList(
+  Vdbe *p                   /* The VDBE */
+){
+  Mem *pSub = 0;                       /* Memory cell hold array of subprogs */
+  sqlite3 *db = p->db;                 /* The database connection */
+  int i;                               /* Loop counter */
+  int rc = SQLITE_OK;                  /* Return code */
+  Mem *pMem = &p->aMem[1];             /* First Mem of result set */
+  int bListSubprogs = (p->explain==1 || (db->flags & SQLITE_TriggerEQP)!=0);
+  Op *aOp;                             /* Array of opcodes */
+  Op *pOp;                             /* Current opcode */
+
+  assert( p->explain );
+  assert( p->eVdbeState==VDBE_RUN_STATE );
+  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY || p->rc==SQLITE_NOMEM );
+
+  /* Even though this opcode does not use dynamic strings for
+  ** the result, result columns may become dynamic if the user calls
+  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
+  */
+  releaseMemArray(pMem, 8);
+
+  if( p->rc==SQLITE_NOMEM ){
+    /* This happens if a malloc() inside a call to sqlite3_column_text() or
+    ** sqlite3_column_text16() failed.  */
+    sqlite3OomFault(db);
+    return SQLITE_ERROR;
+  }
+
+  if( bListSubprogs ){
+    /* The first 8 memory cells are used for the result set.  So we will
+    ** commandeer the 9th cell to use as storage for an array of pointers
+    ** to trigger subprograms.  The VDBE is guaranteed to have at least 9
+    ** cells.  */
+    assert( p->nMem>9 );
+    pSub = &p->aMem[9];
+  }else{
+    pSub = 0;
+  }
+
+  /* Figure out which opcode is next to display */
+  rc = sqlite3VdbeNextOpcode(p, pSub, p->explain==2, &p->pc, &i, &aOp);
+
+  if( rc==SQLITE_OK ){
+    pOp = aOp + i;
+    if( AtomicLoad(&db->u1.isInterrupted) ){
+      p->rc = SQLITE_INTERRUPT;
+      rc = SQLITE_ERROR;
+      sqlite3VdbeError(p, sqlite3ErrStr(p->rc));
+    }else{
+      char *zP4 = sqlite3VdbeDisplayP4(db, pOp);
+      if( p->explain==2 ){
+        sqlite3VdbeMemSetInt64(pMem, pOp->p1);
+        sqlite3VdbeMemSetInt64(pMem+1, pOp->p2);
+        sqlite3VdbeMemSetInt64(pMem+2, pOp->p3);
+        sqlite3VdbeMemSetStr(pMem+3, zP4, -1, SQLITE_UTF8, sqlite3_free);
+        assert( p->nResColumn==4 );
+      }else{
+        sqlite3VdbeMemSetInt64(pMem+0, i);
+        sqlite3VdbeMemSetStr(pMem+1, (char*)sqlite3OpcodeName(pOp->opcode),
+                             -1, SQLITE_UTF8, SQLITE_STATIC);
+        sqlite3VdbeMemSetInt64(pMem+2, pOp->p1);
+        sqlite3VdbeMemSetInt64(pMem+3, pOp->p2);
+        sqlite3VdbeMemSetInt64(pMem+4, pOp->p3);
+        /* pMem+5 for p4 is done last */
+        sqlite3VdbeMemSetInt64(pMem+6, pOp->p5);
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+        {
+          char *zCom = sqlite3VdbeDisplayComment(db, pOp, zP4);
+          sqlite3VdbeMemSetStr(pMem+7, zCom, -1, SQLITE_UTF8, sqlite3_free);
+        }
+#else
+        sqlite3VdbeMemSetNull(pMem+7);
+#endif
+        sqlite3VdbeMemSetStr(pMem+5, zP4, -1, SQLITE_UTF8, sqlite3_free);
+        assert( p->nResColumn==8 );
+      }
+      p->pResultRow = pMem;
+      if( db->mallocFailed ){
+        p->rc = SQLITE_NOMEM;
+        rc = SQLITE_ERROR;
+      }else{
+        p->rc = SQLITE_OK;
+        rc = SQLITE_ROW;
+      }
+    }
+  }
+  return rc;
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+
+#ifdef SQLITE_DEBUG
+/*
+** Print the SQL that was used to generate a VDBE program.
+*/
+SQLITE_PRIVATE void sqlite3VdbePrintSql(Vdbe *p){
+  const char *z = 0;
+  if( p->zSql ){
+    z = p->zSql;
+  }else if( p->nOp>=1 ){
+    const VdbeOp *pOp = &p->aOp[0];
+    if( pOp->opcode==OP_Init && pOp->p4.z!=0 ){
+      z = pOp->p4.z;
+      while( sqlite3Isspace(*z) ) z++;
+    }
+  }
+  if( z ) printf("SQL: [%s]\n", z);
+}
+#endif
+
+#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
+/*
+** Print an IOTRACE message showing SQL content.
+*/
+SQLITE_PRIVATE void sqlite3VdbeIOTraceSql(Vdbe *p){
+  int nOp = p->nOp;
+  VdbeOp *pOp;
+  if( sqlite3IoTrace==0 ) return;
+  if( nOp<1 ) return;
+  pOp = &p->aOp[0];
+  if( pOp->opcode==OP_Init && pOp->p4.z!=0 ){
+    int i, j;
+    char z[1000];
+    sqlite3_snprintf(sizeof(z), z, "%s", pOp->p4.z);
+    for(i=0; sqlite3Isspace(z[i]); i++){}
+    for(j=0; z[i]; i++){
+      if( sqlite3Isspace(z[i]) ){
+        if( z[i-1]!=' ' ){
+          z[j++] = ' ';
+        }
+      }else{
+        z[j++] = z[i];
+      }
+    }
+    z[j] = 0;
+    sqlite3IoTrace("SQL %s\n", z);
+  }
+}
+#endif /* !SQLITE_OMIT_TRACE && SQLITE_ENABLE_IOTRACE */
+
+/* An instance of this object describes bulk memory available for use
+** by subcomponents of a prepared statement.  Space is allocated out
+** of a ReusableSpace object by the allocSpace() routine below.
+*/
+struct ReusableSpace {
+  u8 *pSpace;            /* Available memory */
+  sqlite3_int64 nFree;   /* Bytes of available memory */
+  sqlite3_int64 nNeeded; /* Total bytes that could not be allocated */
+};
+
+/* Try to allocate nByte bytes of 8-byte aligned bulk memory for pBuf
+** from the ReusableSpace object.  Return a pointer to the allocated
+** memory on success.  If insufficient memory is available in the
+** ReusableSpace object, increase the ReusableSpace.nNeeded
+** value by the amount needed and return NULL.
+**
+** If pBuf is not initially NULL, that means that the memory has already
+** been allocated by a prior call to this routine, so just return a copy
+** of pBuf and leave ReusableSpace unchanged.
+**
+** This allocator is employed to repurpose unused slots at the end of the
+** opcode array of prepared state for other memory needs of the prepared
+** statement.
+*/
+static void *allocSpace(
+  struct ReusableSpace *p,  /* Bulk memory available for allocation */
+  void *pBuf,               /* Pointer to a prior allocation */
+  sqlite3_int64 nByte       /* Bytes of memory needed. */
+){
+  assert( EIGHT_BYTE_ALIGNMENT(p->pSpace) );
+  if( pBuf==0 ){
+    nByte = ROUND8P(nByte);
+    if( nByte <= p->nFree ){
+      p->nFree -= nByte;
+      pBuf = &p->pSpace[p->nFree];
+    }else{
+      p->nNeeded += nByte;
+    }
+  }
+  assert( EIGHT_BYTE_ALIGNMENT(pBuf) );
+  return pBuf;
+}
+
+/*
+** Rewind the VDBE back to the beginning in preparation for
+** running it.
+*/
+SQLITE_PRIVATE void sqlite3VdbeRewind(Vdbe *p){
+#if defined(SQLITE_DEBUG)
+  int i;
+#endif
+  assert( p!=0 );
+  assert( p->eVdbeState==VDBE_INIT_STATE
+       || p->eVdbeState==VDBE_READY_STATE
+       || p->eVdbeState==VDBE_HALT_STATE );
+
+  /* There should be at least one opcode.
+  */
+  assert( p->nOp>0 );
+
+  p->eVdbeState = VDBE_READY_STATE;
+
+#ifdef SQLITE_DEBUG
+  for(i=0; i<p->nMem; i++){
+    assert( p->aMem[i].db==p->db );
+  }
+#endif
+  p->pc = -1;
+  p->rc = SQLITE_OK;
+  p->errorAction = OE_Abort;
+  p->nChange = 0;
+  p->cacheCtr = 1;
+  p->minWriteFileFormat = 255;
+  p->iStatement = 0;
+  p->nFkConstraint = 0;
+#ifdef VDBE_PROFILE
+  for(i=0; i<p->nOp; i++){
+    p->aOp[i].nExec = 0;
+    p->aOp[i].nCycle = 0;
+  }
+#endif
+}
+
+/*
+** Prepare a virtual machine for execution for the first time after
+** creating the virtual machine.  This involves things such
+** as allocating registers and initializing the program counter.
+** After the VDBE has be prepped, it can be executed by one or more
+** calls to sqlite3VdbeExec().
+**
+** This function may be called exactly once on each virtual machine.
+** After this routine is called the VM has been "packaged" and is ready
+** to run.  After this routine is called, further calls to
+** sqlite3VdbeAddOp() functions are prohibited.  This routine disconnects
+** the Vdbe from the Parse object that helped generate it so that the
+** the Vdbe becomes an independent entity and the Parse object can be
+** destroyed.
+**
+** Use the sqlite3VdbeRewind() procedure to restore a virtual machine back
+** to its initial state after it has been run.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMakeReady(
+  Vdbe *p,                       /* The VDBE */
+  Parse *pParse                  /* Parsing context */
+){
+  sqlite3 *db;                   /* The database connection */
+  int nVar;                      /* Number of parameters */
+  int nMem;                      /* Number of VM memory registers */
+  int nCursor;                   /* Number of cursors required */
+  int nArg;                      /* Number of arguments in subprograms */
+  int n;                         /* Loop counter */
+  struct ReusableSpace x;        /* Reusable bulk memory */
+
+  assert( p!=0 );
+  assert( p->nOp>0 );
+  assert( pParse!=0 );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  assert( pParse==p->pParse );
+  assert( pParse->db==p->db );
+  p->pVList = pParse->pVList;
+  pParse->pVList =  0;
+  db = p->db;
+  assert( db->mallocFailed==0 );
+  nVar = pParse->nVar;
+  nMem = pParse->nMem;
+  nCursor = pParse->nTab;
+  nArg = pParse->nMaxArg;
+
+  /* Each cursor uses a memory cell.  The first cursor (cursor 0) can
+  ** use aMem[0] which is not otherwise used by the VDBE program.  Allocate
+  ** space at the end of aMem[] for cursors 1 and greater.
+  ** See also: allocateCursor().
+  */
+  nMem += nCursor;
+  if( nCursor==0 && nMem>0 ) nMem++;  /* Space for aMem[0] even if not used */
+
+  /* Figure out how much reusable memory is available at the end of the
+  ** opcode array.  This extra memory will be reallocated for other elements
+  ** of the prepared statement.
+  */
+  n = ROUND8P(sizeof(Op)*p->nOp);             /* Bytes of opcode memory used */
+  x.pSpace = &((u8*)p->aOp)[n];               /* Unused opcode memory */
+  assert( EIGHT_BYTE_ALIGNMENT(x.pSpace) );
+  x.nFree = ROUNDDOWN8(pParse->szOpAlloc - n);  /* Bytes of unused memory */
+  assert( x.nFree>=0 );
+  assert( EIGHT_BYTE_ALIGNMENT(&x.pSpace[x.nFree]) );
+
+  resolveP2Values(p, &nArg);
+  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
+  if( pParse->explain ){
+    if( nMem<10 ) nMem = 10;
+    p->explain = pParse->explain;
+    p->nResColumn = 12 - 4*p->explain;
+  }
+  p->expired = 0;
+
+  /* Memory for registers, parameters, cursor, etc, is allocated in one or two
+  ** passes.  On the first pass, we try to reuse unused memory at the
+  ** end of the opcode array.  If we are unable to satisfy all memory
+  ** requirements by reusing the opcode array tail, then the second
+  ** pass will fill in the remainder using a fresh memory allocation.
+  **
+  ** This two-pass approach that reuses as much memory as possible from
+  ** the leftover memory at the end of the opcode array.  This can significantly
+  ** reduce the amount of memory held by a prepared statement.
+  */
+  x.nNeeded = 0;
+  p->aMem = allocSpace(&x, 0, nMem*sizeof(Mem));
+  p->aVar = allocSpace(&x, 0, nVar*sizeof(Mem));
+  p->apArg = allocSpace(&x, 0, nArg*sizeof(Mem*));
+  p->apCsr = allocSpace(&x, 0, nCursor*sizeof(VdbeCursor*));
+  if( x.nNeeded ){
+    x.pSpace = p->pFree = sqlite3DbMallocRawNN(db, x.nNeeded);
+    x.nFree = x.nNeeded;
+    if( !db->mallocFailed ){
+      p->aMem = allocSpace(&x, p->aMem, nMem*sizeof(Mem));
+      p->aVar = allocSpace(&x, p->aVar, nVar*sizeof(Mem));
+      p->apArg = allocSpace(&x, p->apArg, nArg*sizeof(Mem*));
+      p->apCsr = allocSpace(&x, p->apCsr, nCursor*sizeof(VdbeCursor*));
+    }
+  }
+
+  if( db->mallocFailed ){
+    p->nVar = 0;
+    p->nCursor = 0;
+    p->nMem = 0;
+  }else{
+    p->nCursor = nCursor;
+    p->nVar = (ynVar)nVar;
+    initMemArray(p->aVar, nVar, db, MEM_Null);
+    p->nMem = nMem;
+    initMemArray(p->aMem, nMem, db, MEM_Undefined);
+    memset(p->apCsr, 0, nCursor*sizeof(VdbeCursor*));
+  }
+  sqlite3VdbeRewind(p);
+}
+
+/*
+** Close a VDBE cursor and release all the resources that cursor
+** happens to hold.
+*/
+SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *p, VdbeCursor *pCx){
+  if( pCx ) sqlite3VdbeFreeCursorNN(p,pCx);
+}
+static SQLITE_NOINLINE void freeCursorWithCache(Vdbe *p, VdbeCursor *pCx){
+  VdbeTxtBlbCache *pCache = pCx->pCache;
+  assert( pCx->colCache );
+  pCx->colCache = 0;
+  pCx->pCache = 0;
+  if( pCache->pCValue ){
+    sqlite3RCStrUnref(pCache->pCValue);
+    pCache->pCValue = 0;
+  }
+  sqlite3DbFree(p->db, pCache);
+  sqlite3VdbeFreeCursorNN(p, pCx);
+}
+SQLITE_PRIVATE void sqlite3VdbeFreeCursorNN(Vdbe *p, VdbeCursor *pCx){
+  if( pCx->colCache ){
+    freeCursorWithCache(p, pCx);
+    return;
+  }
+  switch( pCx->eCurType ){
+    case CURTYPE_SORTER: {
+      sqlite3VdbeSorterClose(p->db, pCx);
+      break;
+    }
+    case CURTYPE_BTREE: {
+      assert( pCx->uc.pCursor!=0 );
+      sqlite3BtreeCloseCursor(pCx->uc.pCursor);
+      break;
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    case CURTYPE_VTAB: {
+      sqlite3_vtab_cursor *pVCur = pCx->uc.pVCur;
+      const sqlite3_module *pModule = pVCur->pVtab->pModule;
+      assert( pVCur->pVtab->nRef>0 );
+      pVCur->pVtab->nRef--;
+      pModule->xClose(pVCur);
+      break;
+    }
+#endif
+  }
+}
+
+/*
+** Close all cursors in the current frame.
+*/
+static void closeCursorsInFrame(Vdbe *p){
+  int i;
+  for(i=0; i<p->nCursor; i++){
+    VdbeCursor *pC = p->apCsr[i];
+    if( pC ){
+      sqlite3VdbeFreeCursorNN(p, pC);
+      p->apCsr[i] = 0;
+    }
+  }
+}
+
+/*
+** Copy the values stored in the VdbeFrame structure to its Vdbe. This
+** is used, for example, when a trigger sub-program is halted to restore
+** control to the main program.
+*/
+SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *pFrame){
+  Vdbe *v = pFrame->v;
+  closeCursorsInFrame(v);
+  v->aOp = pFrame->aOp;
+  v->nOp = pFrame->nOp;
+  v->aMem = pFrame->aMem;
+  v->nMem = pFrame->nMem;
+  v->apCsr = pFrame->apCsr;
+  v->nCursor = pFrame->nCursor;
+  v->db->lastRowid = pFrame->lastRowid;
+  v->nChange = pFrame->nChange;
+  v->db->nChange = pFrame->nDbChange;
+  sqlite3VdbeDeleteAuxData(v->db, &v->pAuxData, -1, 0);
+  v->pAuxData = pFrame->pAuxData;
+  pFrame->pAuxData = 0;
+  return pFrame->pc;
+}
+
+/*
+** Close all cursors.
+**
+** Also release any dynamic memory held by the VM in the Vdbe.aMem memory
+** cell array. This is necessary as the memory cell array may contain
+** pointers to VdbeFrame objects, which may in turn contain pointers to
+** open cursors.
+*/
+static void closeAllCursors(Vdbe *p){
+  if( p->pFrame ){
+    VdbeFrame *pFrame;
+    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
+    sqlite3VdbeFrameRestore(pFrame);
+    p->pFrame = 0;
+    p->nFrame = 0;
+  }
+  assert( p->nFrame==0 );
+  closeCursorsInFrame(p);
+  releaseMemArray(p->aMem, p->nMem);
+  while( p->pDelFrame ){
+    VdbeFrame *pDel = p->pDelFrame;
+    p->pDelFrame = pDel->pParent;
+    sqlite3VdbeFrameDelete(pDel);
+  }
+
+  /* Delete any auxdata allocations made by the VM */
+  if( p->pAuxData ) sqlite3VdbeDeleteAuxData(p->db, &p->pAuxData, -1, 0);
+  assert( p->pAuxData==0 );
+}
+
+/*
+** Set the number of result columns that will be returned by this SQL
+** statement. This is now set at compile time, rather than during
+** execution of the vdbe program so that sqlite3_column_count() can
+** be called on an SQL statement before sqlite3_step().
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
+  int n;
+  sqlite3 *db = p->db;
+
+  if( p->nResAlloc ){
+    releaseMemArray(p->aColName, p->nResAlloc*COLNAME_N);
+    sqlite3DbFree(db, p->aColName);
+  }
+  n = nResColumn*COLNAME_N;
+  p->nResColumn = p->nResAlloc = (u16)nResColumn;
+  p->aColName = (Mem*)sqlite3DbMallocRawNN(db, sizeof(Mem)*n );
+  if( p->aColName==0 ) return;
+  initMemArray(p->aColName, n, db, MEM_Null);
+}
+
+/*
+** Set the name of the idx'th column to be returned by the SQL statement.
+** zName must be a pointer to a nul terminated string.
+**
+** This call must be made after a call to sqlite3VdbeSetNumCols().
+**
+** The final parameter, xDel, must be one of SQLITE_DYNAMIC, SQLITE_STATIC
+** or SQLITE_TRANSIENT. If it is SQLITE_DYNAMIC, then the buffer pointed
+** to by zName will be freed by sqlite3DbFree() when the vdbe is destroyed.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSetColName(
+  Vdbe *p,                         /* Vdbe being configured */
+  int idx,                         /* Index of column zName applies to */
+  int var,                         /* One of the COLNAME_* constants */
+  const char *zName,               /* Pointer to buffer containing name */
+  void (*xDel)(void*)              /* Memory management strategy for zName */
+){
+  int rc;
+  Mem *pColName;
+  assert( idx<p->nResAlloc );
+  assert( var<COLNAME_N );
+  if( p->db->mallocFailed ){
+    assert( !zName || xDel!=SQLITE_DYNAMIC );
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( p->aColName!=0 );
+  pColName = &(p->aColName[idx+var*p->nResAlloc]);
+  rc = sqlite3VdbeMemSetStr(pColName, zName, -1, SQLITE_UTF8, xDel);
+  assert( rc!=0 || !zName || (pColName->flags&MEM_Term)!=0 );
+  return rc;
+}
+
+/*
+** A read or write transaction may or may not be active on database handle
+** db. If a transaction is active, commit it. If there is a
+** write-transaction spanning more than one database file, this routine
+** takes care of the super-journal trickery.
+*/
+static int vdbeCommit(sqlite3 *db, Vdbe *p){
+  int i;
+  int nTrans = 0;  /* Number of databases with an active write-transaction
+                   ** that are candidates for a two-phase commit using a
+                   ** super-journal */
+  int rc = SQLITE_OK;
+  int needXcommit = 0;
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+  /* With this option, sqlite3VtabSync() is defined to be simply
+  ** SQLITE_OK so p is not used.
+  */
+  UNUSED_PARAMETER(p);
+#endif
+
+  /* Before doing anything else, call the xSync() callback for any
+  ** virtual module tables written in this transaction. This has to
+  ** be done before determining whether a super-journal file is
+  ** required, as an xSync() callback may add an attached database
+  ** to the transaction.
+  */
+  rc = sqlite3VtabSync(db, p);
+
+  /* This loop determines (a) if the commit hook should be invoked and
+  ** (b) how many database files have open write transactions, not
+  ** including the temp database. (b) is important because if more than
+  ** one database file has an open write transaction, a super-journal
+  ** file is required for an atomic commit.
+  */
+  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( sqlite3BtreeTxnState(pBt)==SQLITE_TXN_WRITE ){
+      /* Whether or not a database might need a super-journal depends upon
+      ** its journal mode (among other things).  This matrix determines which
+      ** journal modes use a super-journal and which do not */
+      static const u8 aMJNeeded[] = {
+        /* DELETE   */  1,
+        /* PERSIST   */ 1,
+        /* OFF       */ 0,
+        /* TRUNCATE  */ 1,
+        /* MEMORY    */ 0,
+        /* WAL       */ 0
+      };
+      Pager *pPager;   /* Pager associated with pBt */
+      needXcommit = 1;
+      sqlite3BtreeEnter(pBt);
+      pPager = sqlite3BtreePager(pBt);
+      if( db->aDb[i].safety_level!=PAGER_SYNCHRONOUS_OFF
+       && aMJNeeded[sqlite3PagerGetJournalMode(pPager)]
+       && sqlite3PagerIsMemdb(pPager)==0
+      ){
+        assert( i!=1 );
+        nTrans++;
+      }
+      rc = sqlite3PagerExclusiveLock(pPager);
+      sqlite3BtreeLeave(pBt);
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* If there are any write-transactions at all, invoke the commit hook */
+  if( needXcommit && db->xCommitCallback ){
+    rc = db->xCommitCallback(db->pCommitArg);
+    if( rc ){
+      return SQLITE_CONSTRAINT_COMMITHOOK;
+    }
+  }
+
+  /* The simple case - no more than one database file (not counting the
+  ** TEMP database) has a transaction active.   There is no need for the
+  ** super-journal.
+  **
+  ** If the return value of sqlite3BtreeGetFilename() is a zero length
+  ** string, it means the main database is :memory: or a temp file.  In
+  ** that case we do not support atomic multi-file commits, so use the
+  ** simple case then too.
+  */
+  if( 0==sqlite3Strlen30(sqlite3BtreeGetFilename(db->aDb[0].pBt))
+   || nTrans<=1
+  ){
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeCommitPhaseOne(pBt, 0);
+      }
+    }
+
+    /* Do the commit only if all databases successfully complete phase 1.
+    ** If one of the BtreeCommitPhaseOne() calls fails, this indicates an
+    ** IO error while deleting or truncating a journal file. It is unlikely,
+    ** but could happen. In this case abandon processing and return the error.
+    */
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeCommitPhaseTwo(pBt, 0);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3VtabCommit(db);
+    }
+  }
+
+  /* The complex case - There is a multi-file write-transaction active.
+  ** This requires a super-journal file to ensure the transaction is
+  ** committed atomically.
+  */
+#ifndef SQLITE_OMIT_DISKIO
+  else{
+    sqlite3_vfs *pVfs = db->pVfs;
+    char *zSuper = 0;   /* File-name for the super-journal */
+    char const *zMainFile = sqlite3BtreeGetFilename(db->aDb[0].pBt);
+    sqlite3_file *pSuperJrnl = 0;
+    i64 offset = 0;
+    int res;
+    int retryCount = 0;
+    int nMainFile;
+
+    /* Select a super-journal file name */
+    nMainFile = sqlite3Strlen30(zMainFile);
+    zSuper = sqlite3MPrintf(db, "%.4c%s%.16c", 0,zMainFile,0);
+    if( zSuper==0 ) return SQLITE_NOMEM_BKPT;
+    zSuper += 4;
+    do {
+      u32 iRandom;
+      if( retryCount ){
+        if( retryCount>100 ){
+          sqlite3_log(SQLITE_FULL, "MJ delete: %s", zSuper);
+          sqlite3OsDelete(pVfs, zSuper, 0);
+          break;
+        }else if( retryCount==1 ){
+          sqlite3_log(SQLITE_FULL, "MJ collide: %s", zSuper);
+        }
+      }
+      retryCount++;
+      sqlite3_randomness(sizeof(iRandom), &iRandom);
+      sqlite3_snprintf(13, &zSuper[nMainFile], "-mj%06X9%02X",
+                               (iRandom>>8)&0xffffff, iRandom&0xff);
+      /* The antipenultimate character of the super-journal name must
+      ** be "9" to avoid name collisions when using 8+3 filenames. */
+      assert( zSuper[sqlite3Strlen30(zSuper)-3]=='9' );
+      sqlite3FileSuffix3(zMainFile, zSuper);
+      rc = sqlite3OsAccess(pVfs, zSuper, SQLITE_ACCESS_EXISTS, &res);
+    }while( rc==SQLITE_OK && res );
+    if( rc==SQLITE_OK ){
+      /* Open the super-journal. */
+      rc = sqlite3OsOpenMalloc(pVfs, zSuper, &pSuperJrnl,
+          SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|
+          SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_SUPER_JOURNAL, 0
+      );
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3DbFree(db, zSuper-4);
+      return rc;
+    }
+
+    /* Write the name of each database file in the transaction into the new
+    ** super-journal file. If an error occurs at this point close
+    ** and delete the super-journal file. All the individual journal files
+    ** still have 'null' as the super-journal pointer, so they will roll
+    ** back independently if a failure occurs.
+    */
+    for(i=0; i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( sqlite3BtreeTxnState(pBt)==SQLITE_TXN_WRITE ){
+        char const *zFile = sqlite3BtreeGetJournalname(pBt);
+        if( zFile==0 ){
+          continue;  /* Ignore TEMP and :memory: databases */
+        }
+        assert( zFile[0]!=0 );
+        rc = sqlite3OsWrite(pSuperJrnl, zFile, sqlite3Strlen30(zFile)+1,offset);
+        offset += sqlite3Strlen30(zFile)+1;
+        if( rc!=SQLITE_OK ){
+          sqlite3OsCloseFree(pSuperJrnl);
+          sqlite3OsDelete(pVfs, zSuper, 0);
+          sqlite3DbFree(db, zSuper-4);
+          return rc;
+        }
+      }
+    }
+
+    /* Sync the super-journal file. If the IOCAP_SEQUENTIAL device
+    ** flag is set this is not required.
+    */
+    if( 0==(sqlite3OsDeviceCharacteristics(pSuperJrnl)&SQLITE_IOCAP_SEQUENTIAL)
+     && SQLITE_OK!=(rc = sqlite3OsSync(pSuperJrnl, SQLITE_SYNC_NORMAL))
+    ){
+      sqlite3OsCloseFree(pSuperJrnl);
+      sqlite3OsDelete(pVfs, zSuper, 0);
+      sqlite3DbFree(db, zSuper-4);
+      return rc;
+    }
+
+    /* Sync all the db files involved in the transaction. The same call
+    ** sets the super-journal pointer in each individual journal. If
+    ** an error occurs here, do not delete the super-journal file.
+    **
+    ** If the error occurs during the first call to
+    ** sqlite3BtreeCommitPhaseOne(), then there is a chance that the
+    ** super-journal file will be orphaned. But we cannot delete it,
+    ** in case the super-journal file name was written into the journal
+    ** file before the failure occurred.
+    */
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeCommitPhaseOne(pBt, zSuper);
+      }
+    }
+    sqlite3OsCloseFree(pSuperJrnl);
+    assert( rc!=SQLITE_BUSY );
+    if( rc!=SQLITE_OK ){
+      sqlite3DbFree(db, zSuper-4);
+      return rc;
+    }
+
+    /* Delete the super-journal file. This commits the transaction. After
+    ** doing this the directory is synced again before any individual
+    ** transaction files are deleted.
+    */
+    rc = sqlite3OsDelete(pVfs, zSuper, 1);
+    sqlite3DbFree(db, zSuper-4);
+    zSuper = 0;
+    if( rc ){
+      return rc;
+    }
+
+    /* All files and directories have already been synced, so the following
+    ** calls to sqlite3BtreeCommitPhaseTwo() are only closing files and
+    ** deleting or truncating journals. If something goes wrong while
+    ** this is happening we don't really care. The integrity of the
+    ** transaction is already guaranteed, but some stray 'cold' journals
+    ** may be lying around. Returning an error code won't help matters.
+    */
+    disable_simulated_io_errors();
+    sqlite3BeginBenignMalloc();
+    for(i=0; i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        sqlite3BtreeCommitPhaseTwo(pBt, 1);
+      }
+    }
+    sqlite3EndBenignMalloc();
+    enable_simulated_io_errors();
+
+    sqlite3VtabCommit(db);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** This routine checks that the sqlite3.nVdbeActive count variable
+** matches the number of vdbe's in the list sqlite3.pVdbe that are
+** currently active. An assertion fails if the two counts do not match.
+** This is an internal self-check only - it is not an essential processing
+** step.
+**
+** This is a no-op if NDEBUG is defined.
+*/
+#ifndef NDEBUG
+static void checkActiveVdbeCnt(sqlite3 *db){
+  Vdbe *p;
+  int cnt = 0;
+  int nWrite = 0;
+  int nRead = 0;
+  p = db->pVdbe;
+  while( p ){
+    if( sqlite3_stmt_busy((sqlite3_stmt*)p) ){
+      cnt++;
+      if( p->readOnly==0 ) nWrite++;
+      if( p->bIsReader ) nRead++;
+    }
+    p = p->pVNext;
+  }
+  assert( cnt==db->nVdbeActive );
+  assert( nWrite==db->nVdbeWrite );
+  assert( nRead==db->nVdbeRead );
+}
+#else
+#define checkActiveVdbeCnt(x)
+#endif
+
+/*
+** If the Vdbe passed as the first argument opened a statement-transaction,
+** close it now. Argument eOp must be either SAVEPOINT_ROLLBACK or
+** SAVEPOINT_RELEASE. If it is SAVEPOINT_ROLLBACK, then the statement
+** transaction is rolled back. If eOp is SAVEPOINT_RELEASE, then the
+** statement transaction is committed.
+**
+** If an IO error occurs, an SQLITE_IOERR_XXX error code is returned.
+** Otherwise SQLITE_OK.
+*/
+static SQLITE_NOINLINE int vdbeCloseStatement(Vdbe *p, int eOp){
+  sqlite3 *const db = p->db;
+  int rc = SQLITE_OK;
+  int i;
+  const int iSavepoint = p->iStatement-1;
+
+  assert( eOp==SAVEPOINT_ROLLBACK || eOp==SAVEPOINT_RELEASE);
+  assert( db->nStatement>0 );
+  assert( p->iStatement==(db->nStatement+db->nSavepoint) );
+
+  for(i=0; i<db->nDb; i++){
+    int rc2 = SQLITE_OK;
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      if( eOp==SAVEPOINT_ROLLBACK ){
+        rc2 = sqlite3BtreeSavepoint(pBt, SAVEPOINT_ROLLBACK, iSavepoint);
+      }
+      if( rc2==SQLITE_OK ){
+        rc2 = sqlite3BtreeSavepoint(pBt, SAVEPOINT_RELEASE, iSavepoint);
+      }
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+  }
+  db->nStatement--;
+  p->iStatement = 0;
+
+  if( rc==SQLITE_OK ){
+    if( eOp==SAVEPOINT_ROLLBACK ){
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_ROLLBACK, iSavepoint);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_RELEASE, iSavepoint);
+    }
+  }
+
+  /* If the statement transaction is being rolled back, also restore the
+  ** database handles deferred constraint counter to the value it had when
+  ** the statement transaction was opened.  */
+  if( eOp==SAVEPOINT_ROLLBACK ){
+    db->nDeferredCons = p->nStmtDefCons;
+    db->nDeferredImmCons = p->nStmtDefImmCons;
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3VdbeCloseStatement(Vdbe *p, int eOp){
+  if( p->db->nStatement && p->iStatement ){
+    return vdbeCloseStatement(p, eOp);
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** This function is called when a transaction opened by the database
+** handle associated with the VM passed as an argument is about to be
+** committed. If there are outstanding deferred foreign key constraint
+** violations, return SQLITE_ERROR. Otherwise, SQLITE_OK.
+**
+** If there are outstanding FK violations and this function returns
+** SQLITE_ERROR, set the result of the VM to SQLITE_CONSTRAINT_FOREIGNKEY
+** and write an error message to it. Then return SQLITE_ERROR.
+*/
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+SQLITE_PRIVATE int sqlite3VdbeCheckFk(Vdbe *p, int deferred){
+  sqlite3 *db = p->db;
+  if( (deferred && (db->nDeferredCons+db->nDeferredImmCons)>0)
+   || (!deferred && p->nFkConstraint>0)
+  ){
+    p->rc = SQLITE_CONSTRAINT_FOREIGNKEY;
+    p->errorAction = OE_Abort;
+    sqlite3VdbeError(p, "FOREIGN KEY constraint failed");
+    if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)==0 ) return SQLITE_ERROR;
+    return SQLITE_CONSTRAINT_FOREIGNKEY;
+  }
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** This routine is called the when a VDBE tries to halt.  If the VDBE
+** has made changes and is in autocommit mode, then commit those
+** changes.  If a rollback is needed, then do the rollback.
+**
+** This routine is the only way to move the sqlite3eOpenState of a VM from
+** SQLITE_STATE_RUN to SQLITE_STATE_HALT.  It is harmless to
+** call this on a VM that is in the SQLITE_STATE_HALT state.
+**
+** Return an error code.  If the commit could not complete because of
+** lock contention, return SQLITE_BUSY.  If SQLITE_BUSY is returned, it
+** means the close did not happen and needs to be repeated.
+*/
+SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe *p){
+  int rc;                         /* Used to store transient return codes */
+  sqlite3 *db = p->db;
+
+  /* This function contains the logic that determines if a statement or
+  ** transaction will be committed or rolled back as a result of the
+  ** execution of this virtual machine.
+  **
+  ** If any of the following errors occur:
+  **
+  **     SQLITE_NOMEM
+  **     SQLITE_IOERR
+  **     SQLITE_FULL
+  **     SQLITE_INTERRUPT
+  **
+  ** Then the internal cache might have been left in an inconsistent
+  ** state.  We need to rollback the statement transaction, if there is
+  ** one, or the complete transaction if there is no statement transaction.
+  */
+
+  assert( p->eVdbeState==VDBE_RUN_STATE );
+  if( db->mallocFailed ){
+    p->rc = SQLITE_NOMEM_BKPT;
+  }
+  closeAllCursors(p);
+  checkActiveVdbeCnt(db);
+
+  /* No commit or rollback needed if the program never started or if the
+  ** SQL statement does not read or write a database file.  */
+  if( p->bIsReader ){
+    int mrc;   /* Primary error code from p->rc */
+    int eStatementOp = 0;
+    int isSpecialError;            /* Set to true if a 'special' error */
+
+    /* Lock all btrees used by the statement */
+    sqlite3VdbeEnter(p);
+
+    /* Check for one of the special errors */
+    if( p->rc ){
+      mrc = p->rc & 0xff;
+      isSpecialError = mrc==SQLITE_NOMEM
+                    || mrc==SQLITE_IOERR
+                    || mrc==SQLITE_INTERRUPT
+                    || mrc==SQLITE_FULL;
+    }else{
+      mrc = isSpecialError = 0;
+    }
+    if( isSpecialError ){
+      /* If the query was read-only and the error code is SQLITE_INTERRUPT,
+      ** no rollback is necessary. Otherwise, at least a savepoint
+      ** transaction must be rolled back to restore the database to a
+      ** consistent state.
+      **
+      ** Even if the statement is read-only, it is important to perform
+      ** a statement or transaction rollback operation. If the error
+      ** occurred while writing to the journal, sub-journal or database
+      ** file as part of an effort to free up cache space (see function
+      ** pagerStress() in pager.c), the rollback is required to restore
+      ** the pager to a consistent state.
+      */
+      if( !p->readOnly || mrc!=SQLITE_INTERRUPT ){
+        if( (mrc==SQLITE_NOMEM || mrc==SQLITE_FULL) && p->usesStmtJournal ){
+          eStatementOp = SAVEPOINT_ROLLBACK;
+        }else{
+          /* We are forced to roll back the active transaction. Before doing
+          ** so, abort any other statements this handle currently has active.
+          */
+          sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
+          sqlite3CloseSavepoints(db);
+          db->autoCommit = 1;
+          p->nChange = 0;
+        }
+      }
+    }
+
+    /* Check for immediate foreign key violations. */
+    if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
+      (void)sqlite3VdbeCheckFk(p, 0);
+    }
+
+    /* If the auto-commit flag is set and this is the only active writer
+    ** VM, then we do either a commit or rollback of the current transaction.
+    **
+    ** Note: This block also runs if one of the special errors handled
+    ** above has occurred.
+    */
+    if( !sqlite3VtabInSync(db)
+     && db->autoCommit
+     && db->nVdbeWrite==(p->readOnly==0)
+    ){
+      if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
+        rc = sqlite3VdbeCheckFk(p, 1);
+        if( rc!=SQLITE_OK ){
+          if( NEVER(p->readOnly) ){
+            sqlite3VdbeLeave(p);
+            return SQLITE_ERROR;
+          }
+          rc = SQLITE_CONSTRAINT_FOREIGNKEY;
+        }else if( db->flags & SQLITE_CorruptRdOnly ){
+          rc = SQLITE_CORRUPT;
+          db->flags &= ~SQLITE_CorruptRdOnly;
+        }else{
+          /* The auto-commit flag is true, the vdbe program was successful
+          ** or hit an 'OR FAIL' constraint and there are no deferred foreign
+          ** key constraints to hold up the transaction. This means a commit
+          ** is required. */
+          rc = vdbeCommit(db, p);
+        }
+        if( rc==SQLITE_BUSY && p->readOnly ){
+          sqlite3VdbeLeave(p);
+          return SQLITE_BUSY;
+        }else if( rc!=SQLITE_OK ){
+          sqlite3SystemError(db, rc);
+          p->rc = rc;
+          sqlite3RollbackAll(db, SQLITE_OK);
+          p->nChange = 0;
+        }else{
+          db->nDeferredCons = 0;
+          db->nDeferredImmCons = 0;
+          db->flags &= ~(u64)SQLITE_DeferFKs;
+          sqlite3CommitInternalChanges(db);
+        }
+      }else if( p->rc==SQLITE_SCHEMA && db->nVdbeActive>1 ){
+        p->nChange = 0;
+      }else{
+        sqlite3RollbackAll(db, SQLITE_OK);
+        p->nChange = 0;
+      }
+      db->nStatement = 0;
+    }else if( eStatementOp==0 ){
+      if( p->rc==SQLITE_OK || p->errorAction==OE_Fail ){
+        eStatementOp = SAVEPOINT_RELEASE;
+      }else if( p->errorAction==OE_Abort ){
+        eStatementOp = SAVEPOINT_ROLLBACK;
+      }else{
+        sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
+        sqlite3CloseSavepoints(db);
+        db->autoCommit = 1;
+        p->nChange = 0;
+      }
+    }
+
+    /* If eStatementOp is non-zero, then a statement transaction needs to
+    ** be committed or rolled back. Call sqlite3VdbeCloseStatement() to
+    ** do so. If this operation returns an error, and the current statement
+    ** error code is SQLITE_OK or SQLITE_CONSTRAINT, then promote the
+    ** current statement error code.
+    */
+    if( eStatementOp ){
+      rc = sqlite3VdbeCloseStatement(p, eStatementOp);
+      if( rc ){
+        if( p->rc==SQLITE_OK || (p->rc&0xff)==SQLITE_CONSTRAINT ){
+          p->rc = rc;
+          sqlite3DbFree(db, p->zErrMsg);
+          p->zErrMsg = 0;
+        }
+        sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
+        sqlite3CloseSavepoints(db);
+        db->autoCommit = 1;
+        p->nChange = 0;
+      }
+    }
+
+    /* If this was an INSERT, UPDATE or DELETE and no statement transaction
+    ** has been rolled back, update the database connection change-counter.
+    */
+    if( p->changeCntOn ){
+      if( eStatementOp!=SAVEPOINT_ROLLBACK ){
+        sqlite3VdbeSetChanges(db, p->nChange);
+      }else{
+        sqlite3VdbeSetChanges(db, 0);
+      }
+      p->nChange = 0;
+    }
+
+    /* Release the locks */
+    sqlite3VdbeLeave(p);
+  }
+
+  /* We have successfully halted and closed the VM.  Record this fact. */
+  db->nVdbeActive--;
+  if( !p->readOnly ) db->nVdbeWrite--;
+  if( p->bIsReader ) db->nVdbeRead--;
+  assert( db->nVdbeActive>=db->nVdbeRead );
+  assert( db->nVdbeRead>=db->nVdbeWrite );
+  assert( db->nVdbeWrite>=0 );
+  p->eVdbeState = VDBE_HALT_STATE;
+  checkActiveVdbeCnt(db);
+  if( db->mallocFailed ){
+    p->rc = SQLITE_NOMEM_BKPT;
+  }
+
+  /* If the auto-commit flag is set to true, then any locks that were held
+  ** by connection db have now been released. Call sqlite3ConnectionUnlocked()
+  ** to invoke any required unlock-notify callbacks.
+  */
+  if( db->autoCommit ){
+    sqlite3ConnectionUnlocked(db);
+  }
+
+  assert( db->nVdbeActive>0 || db->autoCommit==0 || db->nStatement==0 );
+  return (p->rc==SQLITE_BUSY ? SQLITE_BUSY : SQLITE_OK);
+}
+
+
+/*
+** Each VDBE holds the result of the most recent sqlite3_step() call
+** in p->rc.  This routine sets that result back to SQLITE_OK.
+*/
+SQLITE_PRIVATE void sqlite3VdbeResetStepResult(Vdbe *p){
+  p->rc = SQLITE_OK;
+}
+
+/*
+** Copy the error code and error message belonging to the VDBE passed
+** as the first argument to its database handle (so that they will be
+** returned by calls to sqlite3_errcode() and sqlite3_errmsg()).
+**
+** This function does not clear the VDBE error code or message, just
+** copies them to the database handle.
+*/
+SQLITE_PRIVATE int sqlite3VdbeTransferError(Vdbe *p){
+  sqlite3 *db = p->db;
+  int rc = p->rc;
+  if( p->zErrMsg ){
+    db->bBenignMalloc++;
+    sqlite3BeginBenignMalloc();
+    if( db->pErr==0 ) db->pErr = sqlite3ValueNew(db);
+    sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, SQLITE_TRANSIENT);
+    sqlite3EndBenignMalloc();
+    db->bBenignMalloc--;
+  }else if( db->pErr ){
+    sqlite3ValueSetNull(db->pErr);
+  }
+  db->errCode = rc;
+  db->errByteOffset = -1;
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_SQLLOG
+/*
+** If an SQLITE_CONFIG_SQLLOG hook is registered and the VM has been run,
+** invoke it.
+*/
+static void vdbeInvokeSqllog(Vdbe *v){
+  if( sqlite3GlobalConfig.xSqllog && v->rc==SQLITE_OK && v->zSql && v->pc>=0 ){
+    char *zExpanded = sqlite3VdbeExpandSql(v, v->zSql);
+    assert( v->db->init.busy==0 );
+    if( zExpanded ){
+      sqlite3GlobalConfig.xSqllog(
+          sqlite3GlobalConfig.pSqllogArg, v->db, zExpanded, 1
+      );
+      sqlite3DbFree(v->db, zExpanded);
+    }
+  }
+}
+#else
+# define vdbeInvokeSqllog(x)
+#endif
+
+/*
+** Clean up a VDBE after execution but do not delete the VDBE just yet.
+** Write any error messages into *pzErrMsg.  Return the result code.
+**
+** After this routine is run, the VDBE should be ready to be executed
+** again.
+**
+** To look at it another way, this routine resets the state of the
+** virtual machine from VDBE_RUN_STATE or VDBE_HALT_STATE back to
+** VDBE_READY_STATE.
+*/
+SQLITE_PRIVATE int sqlite3VdbeReset(Vdbe *p){
+#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
+  int i;
+#endif
+
+  sqlite3 *db;
+  db = p->db;
+
+  /* If the VM did not run to completion or if it encountered an
+  ** error, then it might not have been halted properly.  So halt
+  ** it now.
+  */
+  if( p->eVdbeState==VDBE_RUN_STATE ) sqlite3VdbeHalt(p);
+
+  /* If the VDBE has been run even partially, then transfer the error code
+  ** and error message from the VDBE into the main database structure.  But
+  ** if the VDBE has just been set to run but has not actually executed any
+  ** instructions yet, leave the main database error information unchanged.
+  */
+  if( p->pc>=0 ){
+    vdbeInvokeSqllog(p);
+    if( db->pErr || p->zErrMsg ){
+      sqlite3VdbeTransferError(p);
+    }else{
+      db->errCode = p->rc;
+    }
+  }
+
+  /* Reset register contents and reclaim error message memory.
+  */
+#ifdef SQLITE_DEBUG
+  /* Execute assert() statements to ensure that the Vdbe.apCsr[] and
+  ** Vdbe.aMem[] arrays have already been cleaned up.  */
+  if( p->apCsr ) for(i=0; i<p->nCursor; i++) assert( p->apCsr[i]==0 );
+  if( p->aMem ){
+    for(i=0; i<p->nMem; i++) assert( p->aMem[i].flags==MEM_Undefined );
+  }
+#endif
+  if( p->zErrMsg ){
+    sqlite3DbFree(db, p->zErrMsg);
+    p->zErrMsg = 0;
+  }
+  p->pResultRow = 0;
+#ifdef SQLITE_DEBUG
+  p->nWrite = 0;
+#endif
+
+  /* Save profiling information from this VDBE run.
+  */
+#ifdef VDBE_PROFILE
+  {
+    FILE *out = fopen("vdbe_profile.out", "a");
+    if( out ){
+      fprintf(out, "---- ");
+      for(i=0; i<p->nOp; i++){
+        fprintf(out, "%02x", p->aOp[i].opcode);
+      }
+      fprintf(out, "\n");
+      if( p->zSql ){
+        char c, pc = 0;
+        fprintf(out, "-- ");
+        for(i=0; (c = p->zSql[i])!=0; i++){
+          if( pc=='\n' ) fprintf(out, "-- ");
+          putc(c, out);
+          pc = c;
+        }
+        if( pc!='\n' ) fprintf(out, "\n");
+      }
+      for(i=0; i<p->nOp; i++){
+        char zHdr[100];
+        i64 cnt = p->aOp[i].nExec;
+        i64 cycles = p->aOp[i].nCycle;
+        sqlite3_snprintf(sizeof(zHdr), zHdr, "%6u %12llu %8llu ",
+           cnt,
+           cycles,
+           cnt>0 ? cycles/cnt : 0
+        );
+        fprintf(out, "%s", zHdr);
+        sqlite3VdbePrintOp(out, i, &p->aOp[i]);
+      }
+      fclose(out);
+    }
+  }
+#endif
+  return p->rc & db->errMask;
+}
+
+/*
+** Clean up and delete a VDBE after execution.  Return an integer which is
+** the result code.  Write any error message text into *pzErrMsg.
+*/
+SQLITE_PRIVATE int sqlite3VdbeFinalize(Vdbe *p){
+  int rc = SQLITE_OK;
+  assert( VDBE_RUN_STATE>VDBE_READY_STATE );
+  assert( VDBE_HALT_STATE>VDBE_READY_STATE );
+  assert( VDBE_INIT_STATE<VDBE_READY_STATE );
+  if( p->eVdbeState>=VDBE_READY_STATE ){
+    rc = sqlite3VdbeReset(p);
+    assert( (rc & p->db->errMask)==rc );
+  }
+  sqlite3VdbeDelete(p);
+  return rc;
+}
+
+/*
+** If parameter iOp is less than zero, then invoke the destructor for
+** all auxiliary data pointers currently cached by the VM passed as
+** the first argument.
+**
+** Or, if iOp is greater than or equal to zero, then the destructor is
+** only invoked for those auxiliary data pointers created by the user
+** function invoked by the OP_Function opcode at instruction iOp of
+** VM pVdbe, and only then if:
+**
+**    * the associated function parameter is the 32nd or later (counting
+**      from left to right), or
+**
+**    * the corresponding bit in argument mask is clear (where the first
+**      function parameter corresponds to bit 0 etc.).
+*/
+SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(sqlite3 *db, AuxData **pp, int iOp, int mask){
+  while( *pp ){
+    AuxData *pAux = *pp;
+    if( (iOp<0)
+     || (pAux->iAuxOp==iOp
+          && pAux->iAuxArg>=0
+          && (pAux->iAuxArg>31 || !(mask & MASKBIT32(pAux->iAuxArg))))
+    ){
+      testcase( pAux->iAuxArg==31 );
+      if( pAux->xDeleteAux ){
+        pAux->xDeleteAux(pAux->pAux);
+      }
+      *pp = pAux->pNextAux;
+      sqlite3DbFree(db, pAux);
+    }else{
+      pp= &pAux->pNextAux;
+    }
+  }
+}
+
+/*
+** Free all memory associated with the Vdbe passed as the second argument,
+** except for object itself, which is preserved.
+**
+** The difference between this function and sqlite3VdbeDelete() is that
+** VdbeDelete() also unlinks the Vdbe from the list of VMs associated with
+** the database connection and frees the object itself.
+*/
+static void sqlite3VdbeClearObject(sqlite3 *db, Vdbe *p){
+  SubProgram *pSub, *pNext;
+  assert( db!=0 );
+  assert( p->db==0 || p->db==db );
+  if( p->aColName ){
+    releaseMemArray(p->aColName, p->nResAlloc*COLNAME_N);
+    sqlite3DbNNFreeNN(db, p->aColName);
+  }
+  for(pSub=p->pProgram; pSub; pSub=pNext){
+    pNext = pSub->pNext;
+    vdbeFreeOpArray(db, pSub->aOp, pSub->nOp);
+    sqlite3DbFree(db, pSub);
+  }
+  if( p->eVdbeState!=VDBE_INIT_STATE ){
+    releaseMemArray(p->aVar, p->nVar);
+    if( p->pVList ) sqlite3DbNNFreeNN(db, p->pVList);
+    if( p->pFree ) sqlite3DbNNFreeNN(db, p->pFree);
+  }
+  vdbeFreeOpArray(db, p->aOp, p->nOp);
+  if( p->zSql ) sqlite3DbNNFreeNN(db, p->zSql);
+#ifdef SQLITE_ENABLE_NORMALIZE
+  sqlite3DbFree(db, p->zNormSql);
+  {
+    DblquoteStr *pThis, *pNxt;
+    for(pThis=p->pDblStr; pThis; pThis=pNxt){
+      pNxt = pThis->pNextStr;
+      sqlite3DbFree(db, pThis);
+    }
+  }
+#endif
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  {
+    int i;
+    for(i=0; i<p->nScan; i++){
+      sqlite3DbFree(db, p->aScan[i].zName);
+    }
+    sqlite3DbFree(db, p->aScan);
+  }
+#endif
+}
+
+/*
+** Delete an entire VDBE.
+*/
+SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe *p){
+  sqlite3 *db;
+
+  assert( p!=0 );
+  db = p->db;
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  sqlite3VdbeClearObject(db, p);
+  if( db->pnBytesFreed==0 ){
+    assert( p->ppVPrev!=0 );
+    *p->ppVPrev = p->pVNext;
+    if( p->pVNext ){
+      p->pVNext->ppVPrev = p->ppVPrev;
+    }
+  }
+  sqlite3DbNNFreeNN(db, p);
+}
+
+/*
+** The cursor "p" has a pending seek operation that has not yet been
+** carried out.  Seek the cursor now.  If an error occurs, return
+** the appropriate error code.
+*/
+SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeFinishMoveto(VdbeCursor *p){
+  int res, rc;
+#ifdef SQLITE_TEST
+  extern int sqlite3_search_count;
+#endif
+  assert( p->deferredMoveto );
+  assert( p->isTable );
+  assert( p->eCurType==CURTYPE_BTREE );
+  rc = sqlite3BtreeTableMoveto(p->uc.pCursor, p->movetoTarget, 0, &res);
+  if( rc ) return rc;
+  if( res!=0 ) return SQLITE_CORRUPT_BKPT;
+#ifdef SQLITE_TEST
+  sqlite3_search_count++;
+#endif
+  p->deferredMoveto = 0;
+  p->cacheStatus = CACHE_STALE;
+  return SQLITE_OK;
+}
+
+/*
+** Something has moved cursor "p" out of place.  Maybe the row it was
+** pointed to was deleted out from under it.  Or maybe the btree was
+** rebalanced.  Whatever the cause, try to restore "p" to the place it
+** is supposed to be pointing.  If the row was deleted out from under the
+** cursor, set the cursor to point to a NULL row.
+*/
+SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeHandleMovedCursor(VdbeCursor *p){
+  int isDifferentRow, rc;
+  assert( p->eCurType==CURTYPE_BTREE );
+  assert( p->uc.pCursor!=0 );
+  assert( sqlite3BtreeCursorHasMoved(p->uc.pCursor) );
+  rc = sqlite3BtreeCursorRestore(p->uc.pCursor, &isDifferentRow);
+  p->cacheStatus = CACHE_STALE;
+  if( isDifferentRow ) p->nullRow = 1;
+  return rc;
+}
+
+/*
+** Check to ensure that the cursor is valid.  Restore the cursor
+** if need be.  Return any I/O error from the restore operation.
+*/
+SQLITE_PRIVATE int sqlite3VdbeCursorRestore(VdbeCursor *p){
+  assert( p->eCurType==CURTYPE_BTREE || IsNullCursor(p) );
+  if( sqlite3BtreeCursorHasMoved(p->uc.pCursor) ){
+    return sqlite3VdbeHandleMovedCursor(p);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The following functions:
+**
+** sqlite3VdbeSerialType()
+** sqlite3VdbeSerialTypeLen()
+** sqlite3VdbeSerialLen()
+** sqlite3VdbeSerialPut()  <--- in-lined into OP_MakeRecord as of 2022-04-02
+** sqlite3VdbeSerialGet()
+**
+** encapsulate the code that serializes values for storage in SQLite
+** data and index records. Each serialized value consists of a
+** 'serial-type' and a blob of data. The serial type is an 8-byte unsigned
+** integer, stored as a varint.
+**
+** In an SQLite index record, the serial type is stored directly before
+** the blob of data that it corresponds to. In a table record, all serial
+** types are stored at the start of the record, and the blobs of data at
+** the end. Hence these functions allow the caller to handle the
+** serial-type and data blob separately.
+**
+** The following table describes the various storage classes for data:
+**
+**   serial type        bytes of data      type
+**   --------------     ---------------    ---------------
+**      0                     0            NULL
+**      1                     1            signed integer
+**      2                     2            signed integer
+**      3                     3            signed integer
+**      4                     4            signed integer
+**      5                     6            signed integer
+**      6                     8            signed integer
+**      7                     8            IEEE float
+**      8                     0            Integer constant 0
+**      9                     0            Integer constant 1
+**     10,11                               reserved for expansion
+**    N>=12 and even       (N-12)/2        BLOB
+**    N>=13 and odd        (N-13)/2        text
+**
+** The 8 and 9 types were added in 3.3.0, file format 4.  Prior versions
+** of SQLite will not understand those serial types.
+*/
+
+#if 0 /* Inlined into the OP_MakeRecord opcode */
+/*
+** Return the serial-type for the value stored in pMem.
+**
+** This routine might convert a large MEM_IntReal value into MEM_Real.
+**
+** 2019-07-11:  The primary user of this subroutine was the OP_MakeRecord
+** opcode in the byte-code engine.  But by moving this routine in-line, we
+** can omit some redundant tests and make that opcode a lot faster.  So
+** this routine is now only used by the STAT3 logic and STAT3 support has
+** ended.  The code is kept here for historical reference only.
+*/
+SQLITE_PRIVATE u32 sqlite3VdbeSerialType(Mem *pMem, int file_format, u32 *pLen){
+  int flags = pMem->flags;
+  u32 n;
+
+  assert( pLen!=0 );
+  if( flags&MEM_Null ){
+    *pLen = 0;
+    return 0;
+  }
+  if( flags&(MEM_Int|MEM_IntReal) ){
+    /* Figure out whether to use 1, 2, 4, 6 or 8 bytes. */
+#   define MAX_6BYTE ((((i64)0x00008000)<<32)-1)
+    i64 i = pMem->u.i;
+    u64 u;
+    testcase( flags & MEM_Int );
+    testcase( flags & MEM_IntReal );
+    if( i<0 ){
+      u = ~i;
+    }else{
+      u = i;
+    }
+    if( u<=127 ){
+      if( (i&1)==i && file_format>=4 ){
+        *pLen = 0;
+        return 8+(u32)u;
+      }else{
+        *pLen = 1;
+        return 1;
+      }
+    }
+    if( u<=32767 ){ *pLen = 2; return 2; }
+    if( u<=8388607 ){ *pLen = 3; return 3; }
+    if( u<=2147483647 ){ *pLen = 4; return 4; }
+    if( u<=MAX_6BYTE ){ *pLen = 6; return 5; }
+    *pLen = 8;
+    if( flags&MEM_IntReal ){
+      /* If the value is IntReal and is going to take up 8 bytes to store
+      ** as an integer, then we might as well make it an 8-byte floating
+      ** point value */
+      pMem->u.r = (double)pMem->u.i;
+      pMem->flags &= ~MEM_IntReal;
+      pMem->flags |= MEM_Real;
+      return 7;
+    }
+    return 6;
+  }
+  if( flags&MEM_Real ){
+    *pLen = 8;
+    return 7;
+  }
+  assert( pMem->db->mallocFailed || flags&(MEM_Str|MEM_Blob) );
+  assert( pMem->n>=0 );
+  n = (u32)pMem->n;
+  if( flags & MEM_Zero ){
+    n += pMem->u.nZero;
+  }
+  *pLen = n;
+  return ((n*2) + 12 + ((flags&MEM_Str)!=0));
+}
+#endif /* inlined into OP_MakeRecord */
+
+/*
+** The sizes for serial types less than 128
+*/
+SQLITE_PRIVATE const u8 sqlite3SmallTypeSizes[128] = {
+        /*  0   1   2   3   4   5   6   7   8   9 */
+/*   0 */   0,  1,  2,  3,  4,  6,  8,  8,  0,  0,
+/*  10 */   0,  0,  0,  0,  1,  1,  2,  2,  3,  3,
+/*  20 */   4,  4,  5,  5,  6,  6,  7,  7,  8,  8,
+/*  30 */   9,  9, 10, 10, 11, 11, 12, 12, 13, 13,
+/*  40 */  14, 14, 15, 15, 16, 16, 17, 17, 18, 18,
+/*  50 */  19, 19, 20, 20, 21, 21, 22, 22, 23, 23,
+/*  60 */  24, 24, 25, 25, 26, 26, 27, 27, 28, 28,
+/*  70 */  29, 29, 30, 30, 31, 31, 32, 32, 33, 33,
+/*  80 */  34, 34, 35, 35, 36, 36, 37, 37, 38, 38,
+/*  90 */  39, 39, 40, 40, 41, 41, 42, 42, 43, 43,
+/* 100 */  44, 44, 45, 45, 46, 46, 47, 47, 48, 48,
+/* 110 */  49, 49, 50, 50, 51, 51, 52, 52, 53, 53,
+/* 120 */  54, 54, 55, 55, 56, 56, 57, 57
+};
+
+/*
+** Return the length of the data corresponding to the supplied serial-type.
+*/
+SQLITE_PRIVATE u32 sqlite3VdbeSerialTypeLen(u32 serial_type){
+  if( serial_type>=128 ){
+    return (serial_type-12)/2;
+  }else{
+    assert( serial_type<12
+            || sqlite3SmallTypeSizes[serial_type]==(serial_type - 12)/2 );
+    return sqlite3SmallTypeSizes[serial_type];
+  }
+}
+SQLITE_PRIVATE u8 sqlite3VdbeOneByteSerialTypeLen(u8 serial_type){
+  assert( serial_type<128 );
+  return sqlite3SmallTypeSizes[serial_type];
+}
+
+/*
+** If we are on an architecture with mixed-endian floating
+** points (ex: ARM7) then swap the lower 4 bytes with the
+** upper 4 bytes.  Return the result.
+**
+** For most architectures, this is a no-op.
+**
+** (later):  It is reported to me that the mixed-endian problem
+** on ARM7 is an issue with GCC, not with the ARM7 chip.  It seems
+** that early versions of GCC stored the two words of a 64-bit
+** float in the wrong order.  And that error has been propagated
+** ever since.  The blame is not necessarily with GCC, though.
+** GCC might have just copying the problem from a prior compiler.
+** I am also told that newer versions of GCC that follow a different
+** ABI get the byte order right.
+**
+** Developers using SQLite on an ARM7 should compile and run their
+** application using -DSQLITE_DEBUG=1 at least once.  With DEBUG
+** enabled, some asserts below will ensure that the byte order of
+** floating point values is correct.
+**
+** (2007-08-30)  Frank van Vugt has studied this problem closely
+** and has send his findings to the SQLite developers.  Frank
+** writes that some Linux kernels offer floating point hardware
+** emulation that uses only 32-bit mantissas instead of a full
+** 48-bits as required by the IEEE standard.  (This is the
+** CONFIG_FPE_FASTFPE option.)  On such systems, floating point
+** byte swapping becomes very complicated.  To avoid problems,
+** the necessary byte swapping is carried out using a 64-bit integer
+** rather than a 64-bit float.  Frank assures us that the code here
+** works for him.  We, the developers, have no way to independently
+** verify this, but Frank seems to know what he is talking about
+** so we trust him.
+*/
+#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+SQLITE_PRIVATE u64 sqlite3FloatSwap(u64 in){
+  union {
+    u64 r;
+    u32 i[2];
+  } u;
+  u32 t;
+
+  u.r = in;
+  t = u.i[0];
+  u.i[0] = u.i[1];
+  u.i[1] = t;
+  return u.r;
+}
+#endif /* SQLITE_MIXED_ENDIAN_64BIT_FLOAT */
+
+
+/* Input "x" is a sequence of unsigned characters that represent a
+** big-endian integer.  Return the equivalent native integer
+*/
+#define ONE_BYTE_INT(x)    ((i8)(x)[0])
+#define TWO_BYTE_INT(x)    (256*(i8)((x)[0])|(x)[1])
+#define THREE_BYTE_INT(x)  (65536*(i8)((x)[0])|((x)[1]<<8)|(x)[2])
+#define FOUR_BYTE_UINT(x)  (((u32)(x)[0]<<24)|((x)[1]<<16)|((x)[2]<<8)|(x)[3])
+#define FOUR_BYTE_INT(x) (16777216*(i8)((x)[0])|((x)[1]<<16)|((x)[2]<<8)|(x)[3])
+
+/*
+** Deserialize the data blob pointed to by buf as serial type serial_type
+** and store the result in pMem.
+**
+** This function is implemented as two separate routines for performance.
+** The few cases that require local variables are broken out into a separate
+** routine so that in most cases the overhead of moving the stack pointer
+** is avoided.
+*/
+static void serialGet(
+  const unsigned char *buf,     /* Buffer to deserialize from */
+  u32 serial_type,              /* Serial type to deserialize */
+  Mem *pMem                     /* Memory cell to write value into */
+){
+  u64 x = FOUR_BYTE_UINT(buf);
+  u32 y = FOUR_BYTE_UINT(buf+4);
+  x = (x<<32) + y;
+  if( serial_type==6 ){
+    /* EVIDENCE-OF: R-29851-52272 Value is a big-endian 64-bit
+    ** twos-complement integer. */
+    pMem->u.i = *(i64*)&x;
+    pMem->flags = MEM_Int;
+    testcase( pMem->u.i<0 );
+  }else{
+    /* EVIDENCE-OF: R-57343-49114 Value is a big-endian IEEE 754-2008 64-bit
+    ** floating point number. */
+#if !defined(NDEBUG) && !defined(SQLITE_OMIT_FLOATING_POINT)
+    /* Verify that integers and floating point values use the same
+    ** byte order.  Or, that if SQLITE_MIXED_ENDIAN_64BIT_FLOAT is
+    ** defined that 64-bit floating point values really are mixed
+    ** endian.
+    */
+    static const u64 t1 = ((u64)0x3ff00000)<<32;
+    static const double r1 = 1.0;
+    u64 t2 = t1;
+    swapMixedEndianFloat(t2);
+    assert( sizeof(r1)==sizeof(t2) && memcmp(&r1, &t2, sizeof(r1))==0 );
+#endif
+    assert( sizeof(x)==8 && sizeof(pMem->u.r)==8 );
+    swapMixedEndianFloat(x);
+    memcpy(&pMem->u.r, &x, sizeof(x));
+    pMem->flags = IsNaN(x) ? MEM_Null : MEM_Real;
+  }
+}
+static int serialGet7(
+  const unsigned char *buf,     /* Buffer to deserialize from */
+  Mem *pMem                     /* Memory cell to write value into */
+){
+  u64 x = FOUR_BYTE_UINT(buf);
+  u32 y = FOUR_BYTE_UINT(buf+4);
+  x = (x<<32) + y;
+  assert( sizeof(x)==8 && sizeof(pMem->u.r)==8 );
+  swapMixedEndianFloat(x);
+  memcpy(&pMem->u.r, &x, sizeof(x));
+  if( IsNaN(x) ){
+    pMem->flags = MEM_Null;
+    return 1;
+  }
+  pMem->flags = MEM_Real;
+  return 0;
+}
+SQLITE_PRIVATE void sqlite3VdbeSerialGet(
+  const unsigned char *buf,     /* Buffer to deserialize from */
+  u32 serial_type,              /* Serial type to deserialize */
+  Mem *pMem                     /* Memory cell to write value into */
+){
+  switch( serial_type ){
+    case 10: { /* Internal use only: NULL with virtual table
+               ** UPDATE no-change flag set */
+      pMem->flags = MEM_Null|MEM_Zero;
+      pMem->n = 0;
+      pMem->u.nZero = 0;
+      return;
+    }
+    case 11:   /* Reserved for future use */
+    case 0: {  /* Null */
+      /* EVIDENCE-OF: R-24078-09375 Value is a NULL. */
+      pMem->flags = MEM_Null;
+      return;
+    }
+    case 1: {
+      /* EVIDENCE-OF: R-44885-25196 Value is an 8-bit twos-complement
+      ** integer. */
+      pMem->u.i = ONE_BYTE_INT(buf);
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 2: { /* 2-byte signed integer */
+      /* EVIDENCE-OF: R-49794-35026 Value is a big-endian 16-bit
+      ** twos-complement integer. */
+      pMem->u.i = TWO_BYTE_INT(buf);
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 3: { /* 3-byte signed integer */
+      /* EVIDENCE-OF: R-37839-54301 Value is a big-endian 24-bit
+      ** twos-complement integer. */
+      pMem->u.i = THREE_BYTE_INT(buf);
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 4: { /* 4-byte signed integer */
+      /* EVIDENCE-OF: R-01849-26079 Value is a big-endian 32-bit
+      ** twos-complement integer. */
+      pMem->u.i = FOUR_BYTE_INT(buf);
+#ifdef __HP_cc
+      /* Work around a sign-extension bug in the HP compiler for HP/UX */
+      if( buf[0]&0x80 ) pMem->u.i |= 0xffffffff80000000LL;
+#endif
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 5: { /* 6-byte signed integer */
+      /* EVIDENCE-OF: R-50385-09674 Value is a big-endian 48-bit
+      ** twos-complement integer. */
+      pMem->u.i = FOUR_BYTE_UINT(buf+2) + (((i64)1)<<32)*TWO_BYTE_INT(buf);
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 6:   /* 8-byte signed integer */
+    case 7: { /* IEEE floating point */
+      /* These use local variables, so do them in a separate routine
+      ** to avoid having to move the frame pointer in the common case */
+      serialGet(buf,serial_type,pMem);
+      return;
+    }
+    case 8:    /* Integer 0 */
+    case 9: {  /* Integer 1 */
+      /* EVIDENCE-OF: R-12976-22893 Value is the integer 0. */
+      /* EVIDENCE-OF: R-18143-12121 Value is the integer 1. */
+      pMem->u.i = serial_type-8;
+      pMem->flags = MEM_Int;
+      return;
+    }
+    default: {
+      /* EVIDENCE-OF: R-14606-31564 Value is a BLOB that is (N-12)/2 bytes in
+      ** length.
+      ** EVIDENCE-OF: R-28401-00140 Value is a string in the text encoding and
+      ** (N-13)/2 bytes in length. */
+      static const u16 aFlag[] = { MEM_Blob|MEM_Ephem, MEM_Str|MEM_Ephem };
+      pMem->z = (char *)buf;
+      pMem->n = (serial_type-12)/2;
+      pMem->flags = aFlag[serial_type&1];
+      return;
+    }
+  }
+  return;
+}
+/*
+** This routine is used to allocate sufficient space for an UnpackedRecord
+** structure large enough to be used with sqlite3VdbeRecordUnpack() if
+** the first argument is a pointer to KeyInfo structure pKeyInfo.
+**
+** The space is either allocated using sqlite3DbMallocRaw() or from within
+** the unaligned buffer passed via the second and third arguments (presumably
+** stack space). If the former, then *ppFree is set to a pointer that should
+** be eventually freed by the caller using sqlite3DbFree(). Or, if the
+** allocation comes from the pSpace/szSpace buffer, *ppFree is set to NULL
+** before returning.
+**
+** If an OOM error occurs, NULL is returned.
+*/
+SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(
+  KeyInfo *pKeyInfo               /* Description of the record */
+){
+  UnpackedRecord *p;              /* Unpacked record to return */
+  int nByte;                      /* Number of bytes required for *p */
+  nByte = ROUND8P(sizeof(UnpackedRecord)) + sizeof(Mem)*(pKeyInfo->nKeyField+1);
+  p = (UnpackedRecord *)sqlite3DbMallocRaw(pKeyInfo->db, nByte);
+  if( !p ) return 0;
+  p->aMem = (Mem*)&((char*)p)[ROUND8P(sizeof(UnpackedRecord))];
+  assert( pKeyInfo->aSortFlags!=0 );
+  p->pKeyInfo = pKeyInfo;
+  p->nField = pKeyInfo->nKeyField + 1;
+  return p;
+}
+
+/*
+** Given the nKey-byte encoding of a record in pKey[], populate the
+** UnpackedRecord structure indicated by the fourth argument with the
+** contents of the decoded record.
+*/
+SQLITE_PRIVATE void sqlite3VdbeRecordUnpack(
+  KeyInfo *pKeyInfo,     /* Information about the record format */
+  int nKey,              /* Size of the binary record */
+  const void *pKey,      /* The binary record */
+  UnpackedRecord *p      /* Populate this structure before returning. */
+){
+  const unsigned char *aKey = (const unsigned char *)pKey;
+  u32 d;
+  u32 idx;                        /* Offset in aKey[] to read from */
+  u16 u;                          /* Unsigned loop counter */
+  u32 szHdr;
+  Mem *pMem = p->aMem;
+
+  p->default_rc = 0;
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+  idx = getVarint32(aKey, szHdr);
+  d = szHdr;
+  u = 0;
+  while( idx<szHdr && d<=(u32)nKey ){
+    u32 serial_type;
+
+    idx += getVarint32(&aKey[idx], serial_type);
+    pMem->enc = pKeyInfo->enc;
+    pMem->db = pKeyInfo->db;
+    /* pMem->flags = 0; // sqlite3VdbeSerialGet() will set this for us */
+    pMem->szMalloc = 0;
+    pMem->z = 0;
+    sqlite3VdbeSerialGet(&aKey[d], serial_type, pMem);
+    d += sqlite3VdbeSerialTypeLen(serial_type);
+    pMem++;
+    if( (++u)>=p->nField ) break;
+  }
+  if( d>(u32)nKey && u ){
+    assert( CORRUPT_DB );
+    /* In a corrupt record entry, the last pMem might have been set up using
+    ** uninitialized memory. Overwrite its value with NULL, to prevent
+    ** warnings from MSAN. */
+    sqlite3VdbeMemSetNull(pMem-1);
+  }
+  assert( u<=pKeyInfo->nKeyField + 1 );
+  p->nField = u;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** This function compares two index or table record keys in the same way
+** as the sqlite3VdbeRecordCompare() routine. Unlike VdbeRecordCompare(),
+** this function deserializes and compares values using the
+** sqlite3VdbeSerialGet() and sqlite3MemCompare() functions. It is used
+** in assert() statements to ensure that the optimized code in
+** sqlite3VdbeRecordCompare() returns results with these two primitives.
+**
+** Return true if the result of comparison is equivalent to desiredResult.
+** Return false if there is a disagreement.
+*/
+static int vdbeRecordCompareDebug(
+  int nKey1, const void *pKey1, /* Left key */
+  const UnpackedRecord *pPKey2, /* Right key */
+  int desiredResult             /* Correct answer */
+){
+  u32 d1;            /* Offset into aKey[] of next data element */
+  u32 idx1;          /* Offset into aKey[] of next header element */
+  u32 szHdr1;        /* Number of bytes in header */
+  int i = 0;
+  int rc = 0;
+  const unsigned char *aKey1 = (const unsigned char *)pKey1;
+  KeyInfo *pKeyInfo;
+  Mem mem1;
+
+  pKeyInfo = pPKey2->pKeyInfo;
+  if( pKeyInfo->db==0 ) return 1;
+  mem1.enc = pKeyInfo->enc;
+  mem1.db = pKeyInfo->db;
+  /* mem1.flags = 0;  // Will be initialized by sqlite3VdbeSerialGet() */
+  VVA_ONLY( mem1.szMalloc = 0; ) /* Only needed by assert() statements */
+
+  /* Compilers may complain that mem1.u.i is potentially uninitialized.
+  ** We could initialize it, as shown here, to silence those complaints.
+  ** But in fact, mem1.u.i will never actually be used uninitialized, and doing
+  ** the unnecessary initialization has a measurable negative performance
+  ** impact, since this routine is a very high runner.  And so, we choose
+  ** to ignore the compiler warnings and leave this variable uninitialized.
+  */
+  /*  mem1.u.i = 0;  // not needed, here to silence compiler warning */
+
+  idx1 = getVarint32(aKey1, szHdr1);
+  if( szHdr1>98307 ) return SQLITE_CORRUPT;
+  d1 = szHdr1;
+  assert( pKeyInfo->nAllField>=pPKey2->nField || CORRUPT_DB );
+  assert( pKeyInfo->aSortFlags!=0 );
+  assert( pKeyInfo->nKeyField>0 );
+  assert( idx1<=szHdr1 || CORRUPT_DB );
+  do{
+    u32 serial_type1;
+
+    /* Read the serial types for the next element in each key. */
+    idx1 += getVarint32( aKey1+idx1, serial_type1 );
+
+    /* Verify that there is enough key space remaining to avoid
+    ** a buffer overread.  The "d1+serial_type1+2" subexpression will
+    ** always be greater than or equal to the amount of required key space.
+    ** Use that approximation to avoid the more expensive call to
+    ** sqlite3VdbeSerialTypeLen() in the common case.
+    */
+    if( d1+(u64)serial_type1+2>(u64)nKey1
+     && d1+(u64)sqlite3VdbeSerialTypeLen(serial_type1)>(u64)nKey1
+    ){
+      if( serial_type1>=1
+       && serial_type1<=7
+       && d1+(u64)sqlite3VdbeSerialTypeLen(serial_type1)<=(u64)nKey1+8
+       && CORRUPT_DB
+      ){
+        return 1;  /* corrupt record not detected by
+                   ** sqlite3VdbeRecordCompareWithSkip().  Return true
+                   ** to avoid firing the assert() */
+      }
+      break;
+    }
+
+    /* Extract the values to be compared.
+    */
+    sqlite3VdbeSerialGet(&aKey1[d1], serial_type1, &mem1);
+    d1 += sqlite3VdbeSerialTypeLen(serial_type1);
+
+    /* Do the comparison
+    */
+    rc = sqlite3MemCompare(&mem1, &pPKey2->aMem[i],
+                           pKeyInfo->nAllField>i ? pKeyInfo->aColl[i] : 0);
+    if( rc!=0 ){
+      assert( mem1.szMalloc==0 );  /* See comment below */
+      if( (pKeyInfo->aSortFlags[i] & KEYINFO_ORDER_BIGNULL)
+       && ((mem1.flags & MEM_Null) || (pPKey2->aMem[i].flags & MEM_Null))
+      ){
+        rc = -rc;
+      }
+      if( pKeyInfo->aSortFlags[i] & KEYINFO_ORDER_DESC ){
+        rc = -rc;  /* Invert the result for DESC sort order. */
+      }
+      goto debugCompareEnd;
+    }
+    i++;
+  }while( idx1<szHdr1 && i<pPKey2->nField );
+
+  /* No memory allocation is ever used on mem1.  Prove this using
+  ** the following assert().  If the assert() fails, it indicates a
+  ** memory leak and a need to call sqlite3VdbeMemRelease(&mem1).
+  */
+  assert( mem1.szMalloc==0 );
+
+  /* rc==0 here means that one of the keys ran out of fields and
+  ** all the fields up to that point were equal. Return the default_rc
+  ** value.  */
+  rc = pPKey2->default_rc;
+
+debugCompareEnd:
+  if( desiredResult==0 && rc==0 ) return 1;
+  if( desiredResult<0 && rc<0 ) return 1;
+  if( desiredResult>0 && rc>0 ) return 1;
+  if( CORRUPT_DB ) return 1;
+  if( pKeyInfo->db->mallocFailed ) return 1;
+  return 0;
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Count the number of fields (a.k.a. columns) in the record given by
+** pKey,nKey.  The verify that this count is less than or equal to the
+** limit given by pKeyInfo->nAllField.
+**
+** If this constraint is not satisfied, it means that the high-speed
+** vdbeRecordCompareInt() and vdbeRecordCompareString() routines will
+** not work correctly.  If this assert() ever fires, it probably means
+** that the KeyInfo.nKeyField or KeyInfo.nAllField values were computed
+** incorrectly.
+*/
+static void vdbeAssertFieldCountWithinLimits(
+  int nKey, const void *pKey,   /* The record to verify */
+  const KeyInfo *pKeyInfo       /* Compare size with this KeyInfo */
+){
+  int nField = 0;
+  u32 szHdr;
+  u32 idx;
+  u32 notUsed;
+  const unsigned char *aKey = (const unsigned char*)pKey;
+
+  if( CORRUPT_DB ) return;
+  idx = getVarint32(aKey, szHdr);
+  assert( nKey>=0 );
+  assert( szHdr<=(u32)nKey );
+  while( idx<szHdr ){
+    idx += getVarint32(aKey+idx, notUsed);
+    nField++;
+  }
+  assert( nField <= pKeyInfo->nAllField );
+}
+#else
+# define vdbeAssertFieldCountWithinLimits(A,B,C)
+#endif
+
+/*
+** Both *pMem1 and *pMem2 contain string values. Compare the two values
+** using the collation sequence pColl. As usual, return a negative , zero
+** or positive value if *pMem1 is less than, equal to or greater than
+** *pMem2, respectively. Similar in spirit to "rc = (*pMem1) - (*pMem2);".
+*/
+static int vdbeCompareMemString(
+  const Mem *pMem1,
+  const Mem *pMem2,
+  const CollSeq *pColl,
+  u8 *prcErr                      /* If an OOM occurs, set to SQLITE_NOMEM */
+){
+  if( pMem1->enc==pColl->enc ){
+    /* The strings are already in the correct encoding.  Call the
+     ** comparison function directly */
+    return pColl->xCmp(pColl->pUser,pMem1->n,pMem1->z,pMem2->n,pMem2->z);
+  }else{
+    int rc;
+    const void *v1, *v2;
+    Mem c1;
+    Mem c2;
+    sqlite3VdbeMemInit(&c1, pMem1->db, MEM_Null);
+    sqlite3VdbeMemInit(&c2, pMem1->db, MEM_Null);
+    sqlite3VdbeMemShallowCopy(&c1, pMem1, MEM_Ephem);
+    sqlite3VdbeMemShallowCopy(&c2, pMem2, MEM_Ephem);
+    v1 = sqlite3ValueText((sqlite3_value*)&c1, pColl->enc);
+    v2 = sqlite3ValueText((sqlite3_value*)&c2, pColl->enc);
+    if( (v1==0 || v2==0) ){
+      if( prcErr ) *prcErr = SQLITE_NOMEM_BKPT;
+      rc = 0;
+    }else{
+      rc = pColl->xCmp(pColl->pUser, c1.n, v1, c2.n, v2);
+    }
+    sqlite3VdbeMemReleaseMalloc(&c1);
+    sqlite3VdbeMemReleaseMalloc(&c2);
+    return rc;
+  }
+}
+
+/*
+** The input pBlob is guaranteed to be a Blob that is not marked
+** with MEM_Zero.  Return true if it could be a zero-blob.
+*/
+static int isAllZero(const char *z, int n){
+  int i;
+  for(i=0; i<n; i++){
+    if( z[i] ) return 0;
+  }
+  return 1;
+}
+
+/*
+** Compare two blobs.  Return negative, zero, or positive if the first
+** is less than, equal to, or greater than the second, respectively.
+** If one blob is a prefix of the other, then the shorter is the lessor.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3BlobCompare(const Mem *pB1, const Mem *pB2){
+  int c;
+  int n1 = pB1->n;
+  int n2 = pB2->n;
+
+  /* It is possible to have a Blob value that has some non-zero content
+  ** followed by zero content.  But that only comes up for Blobs formed
+  ** by the OP_MakeRecord opcode, and such Blobs never get passed into
+  ** sqlite3MemCompare(). */
+  assert( (pB1->flags & MEM_Zero)==0 || n1==0 );
+  assert( (pB2->flags & MEM_Zero)==0 || n2==0 );
+
+  if( (pB1->flags|pB2->flags) & MEM_Zero ){
+    if( pB1->flags & pB2->flags & MEM_Zero ){
+      return pB1->u.nZero - pB2->u.nZero;
+    }else if( pB1->flags & MEM_Zero ){
+      if( !isAllZero(pB2->z, pB2->n) ) return -1;
+      return pB1->u.nZero - n2;
+    }else{
+      if( !isAllZero(pB1->z, pB1->n) ) return +1;
+      return n1 - pB2->u.nZero;
+    }
+  }
+  c = memcmp(pB1->z, pB2->z, n1>n2 ? n2 : n1);
+  if( c ) return c;
+  return n1 - n2;
+}
+
+/* The following two functions are used only within testcase() to prove
+** test coverage.  These functions do no exist for production builds.
+** We must use separate SQLITE_NOINLINE functions here, since otherwise
+** optimizer code movement causes gcov to become very confused.
+*/
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_DEBUG)
+static int SQLITE_NOINLINE doubleLt(double a, double b){ return a<b; }
+static int SQLITE_NOINLINE doubleEq(double a, double b){ return a==b; }
+#endif
+
+/*
+** Do a comparison between a 64-bit signed integer and a 64-bit floating-point
+** number.  Return negative, zero, or positive if the first (i64) is less than,
+** equal to, or greater than the second (double).
+*/
+SQLITE_PRIVATE int sqlite3IntFloatCompare(i64 i, double r){
+  if( sqlite3IsNaN(r) ){
+    /* SQLite considers NaN to be a NULL. And all integer values are greater
+    ** than NULL */
+    return 1;
+  }else{
+    i64 y;
+    if( r<-9223372036854775808.0 ) return +1;
+    if( r>=9223372036854775808.0 ) return -1;
+    y = (i64)r;
+    if( i<y ) return -1;
+    if( i>y ) return +1;
+    testcase( doubleLt(((double)i),r) );
+    testcase( doubleLt(r,((double)i)) );
+    testcase( doubleEq(r,((double)i)) );
+    return (((double)i)<r) ? -1 : (((double)i)>r);
+  }
+}
+
+/*
+** Compare the values contained by the two memory cells, returning
+** negative, zero or positive if pMem1 is less than, equal to, or greater
+** than pMem2. Sorting order is NULL's first, followed by numbers (integers
+** and reals) sorted numerically, followed by text ordered by the collating
+** sequence pColl and finally blob's ordered by memcmp().
+**
+** Two NULL values are considered equal by this function.
+*/
+SQLITE_PRIVATE int sqlite3MemCompare(const Mem *pMem1, const Mem *pMem2, const CollSeq *pColl){
+  int f1, f2;
+  int combined_flags;
+
+  f1 = pMem1->flags;
+  f2 = pMem2->flags;
+  combined_flags = f1|f2;
+  assert( !sqlite3VdbeMemIsRowSet(pMem1) && !sqlite3VdbeMemIsRowSet(pMem2) );
+
+  /* If one value is NULL, it is less than the other. If both values
+  ** are NULL, return 0.
+  */
+  if( combined_flags&MEM_Null ){
+    return (f2&MEM_Null) - (f1&MEM_Null);
+  }
+
+  /* At least one of the two values is a number
+  */
+  if( combined_flags&(MEM_Int|MEM_Real|MEM_IntReal) ){
+    testcase( combined_flags & MEM_Int );
+    testcase( combined_flags & MEM_Real );
+    testcase( combined_flags & MEM_IntReal );
+    if( (f1 & f2 & (MEM_Int|MEM_IntReal))!=0 ){
+      testcase( f1 & f2 & MEM_Int );
+      testcase( f1 & f2 & MEM_IntReal );
+      if( pMem1->u.i < pMem2->u.i ) return -1;
+      if( pMem1->u.i > pMem2->u.i ) return +1;
+      return 0;
+    }
+    if( (f1 & f2 & MEM_Real)!=0 ){
+      if( pMem1->u.r < pMem2->u.r ) return -1;
+      if( pMem1->u.r > pMem2->u.r ) return +1;
+      return 0;
+    }
+    if( (f1&(MEM_Int|MEM_IntReal))!=0 ){
+      testcase( f1 & MEM_Int );
+      testcase( f1 & MEM_IntReal );
+      if( (f2&MEM_Real)!=0 ){
+        return sqlite3IntFloatCompare(pMem1->u.i, pMem2->u.r);
+      }else if( (f2&(MEM_Int|MEM_IntReal))!=0 ){
+        if( pMem1->u.i < pMem2->u.i ) return -1;
+        if( pMem1->u.i > pMem2->u.i ) return +1;
+        return 0;
+      }else{
+        return -1;
+      }
+    }
+    if( (f1&MEM_Real)!=0 ){
+      if( (f2&(MEM_Int|MEM_IntReal))!=0 ){
+        testcase( f2 & MEM_Int );
+        testcase( f2 & MEM_IntReal );
+        return -sqlite3IntFloatCompare(pMem2->u.i, pMem1->u.r);
+      }else{
+        return -1;
+      }
+    }
+    return +1;
+  }
+
+  /* If one value is a string and the other is a blob, the string is less.
+  ** If both are strings, compare using the collating functions.
+  */
+  if( combined_flags&MEM_Str ){
+    if( (f1 & MEM_Str)==0 ){
+      return 1;
+    }
+    if( (f2 & MEM_Str)==0 ){
+      return -1;
+    }
+
+    assert( pMem1->enc==pMem2->enc || pMem1->db->mallocFailed );
+    assert( pMem1->enc==SQLITE_UTF8 ||
+            pMem1->enc==SQLITE_UTF16LE || pMem1->enc==SQLITE_UTF16BE );
+
+    /* The collation sequence must be defined at this point, even if
+    ** the user deletes the collation sequence after the vdbe program is
+    ** compiled (this was not always the case).
+    */
+    assert( !pColl || pColl->xCmp );
+
+    if( pColl ){
+      return vdbeCompareMemString(pMem1, pMem2, pColl, 0);
+    }
+    /* If a NULL pointer was passed as the collate function, fall through
+    ** to the blob case and use memcmp().  */
+  }
+
+  /* Both values must be blobs.  Compare using memcmp().  */
+  return sqlite3BlobCompare(pMem1, pMem2);
+}
+
+
+/*
+** The first argument passed to this function is a serial-type that
+** corresponds to an integer - all values between 1 and 9 inclusive
+** except 7. The second points to a buffer containing an integer value
+** serialized according to serial_type. This function deserializes
+** and returns the value.
+*/
+static i64 vdbeRecordDecodeInt(u32 serial_type, const u8 *aKey){
+  u32 y;
+  assert( CORRUPT_DB || (serial_type>=1 && serial_type<=9 && serial_type!=7) );
+  switch( serial_type ){
+    case 0:
+    case 1:
+      testcase( aKey[0]&0x80 );
+      return ONE_BYTE_INT(aKey);
+    case 2:
+      testcase( aKey[0]&0x80 );
+      return TWO_BYTE_INT(aKey);
+    case 3:
+      testcase( aKey[0]&0x80 );
+      return THREE_BYTE_INT(aKey);
+    case 4: {
+      testcase( aKey[0]&0x80 );
+      y = FOUR_BYTE_UINT(aKey);
+      return (i64)*(int*)&y;
+    }
+    case 5: {
+      testcase( aKey[0]&0x80 );
+      return FOUR_BYTE_UINT(aKey+2) + (((i64)1)<<32)*TWO_BYTE_INT(aKey);
+    }
+    case 6: {
+      u64 x = FOUR_BYTE_UINT(aKey);
+      testcase( aKey[0]&0x80 );
+      x = (x<<32) | FOUR_BYTE_UINT(aKey+4);
+      return (i64)*(i64*)&x;
+    }
+  }
+
+  return (serial_type - 8);
+}
+
+/*
+** This function compares the two table rows or index records
+** specified by {nKey1, pKey1} and pPKey2.  It returns a negative, zero
+** or positive integer if key1 is less than, equal to or
+** greater than key2.  The {nKey1, pKey1} key must be a blob
+** created by the OP_MakeRecord opcode of the VDBE.  The pPKey2
+** key must be a parsed key such as obtained from
+** sqlite3VdbeParseRecord.
+**
+** If argument bSkip is non-zero, it is assumed that the caller has already
+** determined that the first fields of the keys are equal.
+**
+** Key1 and Key2 do not have to contain the same number of fields. If all
+** fields that appear in both keys are equal, then pPKey2->default_rc is
+** returned.
+**
+** If database corruption is discovered, set pPKey2->errCode to
+** SQLITE_CORRUPT and return 0. If an OOM error is encountered,
+** pPKey2->errCode is set to SQLITE_NOMEM and, if it is not NULL, the
+** malloc-failed flag set on database handle (pPKey2->pKeyInfo->db).
+*/
+SQLITE_PRIVATE int sqlite3VdbeRecordCompareWithSkip(
+  int nKey1, const void *pKey1,   /* Left key */
+  UnpackedRecord *pPKey2,         /* Right key */
+  int bSkip                       /* If true, skip the first field */
+){
+  u32 d1;                         /* Offset into aKey[] of next data element */
+  int i;                          /* Index of next field to compare */
+  u32 szHdr1;                     /* Size of record header in bytes */
+  u32 idx1;                       /* Offset of first type in header */
+  int rc = 0;                     /* Return value */
+  Mem *pRhs = pPKey2->aMem;       /* Next field of pPKey2 to compare */
+  KeyInfo *pKeyInfo;
+  const unsigned char *aKey1 = (const unsigned char *)pKey1;
+  Mem mem1;
+
+  /* If bSkip is true, then the caller has already determined that the first
+  ** two elements in the keys are equal. Fix the various stack variables so
+  ** that this routine begins comparing at the second field. */
+  if( bSkip ){
+    u32 s1 = aKey1[1];
+    if( s1<0x80 ){
+      idx1 = 2;
+    }else{
+      idx1 = 1 + sqlite3GetVarint32(&aKey1[1], &s1);
+    }
+    szHdr1 = aKey1[0];
+    d1 = szHdr1 + sqlite3VdbeSerialTypeLen(s1);
+    i = 1;
+    pRhs++;
+  }else{
+    if( (szHdr1 = aKey1[0])<0x80 ){
+      idx1 = 1;
+    }else{
+      idx1 = sqlite3GetVarint32(aKey1, &szHdr1);
+    }
+    d1 = szHdr1;
+    i = 0;
+  }
+  if( d1>(unsigned)nKey1 ){
+    pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+    return 0;  /* Corruption */
+  }
+
+  VVA_ONLY( mem1.szMalloc = 0; ) /* Only needed by assert() statements */
+  assert( pPKey2->pKeyInfo->nAllField>=pPKey2->nField
+       || CORRUPT_DB );
+  assert( pPKey2->pKeyInfo->aSortFlags!=0 );
+  assert( pPKey2->pKeyInfo->nKeyField>0 );
+  assert( idx1<=szHdr1 || CORRUPT_DB );
+  while( 1 /*exit-by-break*/ ){
+    u32 serial_type;
+
+    /* RHS is an integer */
+    if( pRhs->flags & (MEM_Int|MEM_IntReal) ){
+      testcase( pRhs->flags & MEM_Int );
+      testcase( pRhs->flags & MEM_IntReal );
+      serial_type = aKey1[idx1];
+      testcase( serial_type==12 );
+      if( serial_type>=10 ){
+        rc = serial_type==10 ? -1 : +1;
+      }else if( serial_type==0 ){
+        rc = -1;
+      }else if( serial_type==7 ){
+        serialGet7(&aKey1[d1], &mem1);
+        rc = -sqlite3IntFloatCompare(pRhs->u.i, mem1.u.r);
+      }else{
+        i64 lhs = vdbeRecordDecodeInt(serial_type, &aKey1[d1]);
+        i64 rhs = pRhs->u.i;
+        if( lhs<rhs ){
+          rc = -1;
+        }else if( lhs>rhs ){
+          rc = +1;
+        }
+      }
+    }
+
+    /* RHS is real */
+    else if( pRhs->flags & MEM_Real ){
+      serial_type = aKey1[idx1];
+      if( serial_type>=10 ){
+        /* Serial types 12 or greater are strings and blobs (greater than
+        ** numbers). Types 10 and 11 are currently "reserved for future
+        ** use", so it doesn't really matter what the results of comparing
+        ** them to numeric values are.  */
+        rc = serial_type==10 ? -1 : +1;
+      }else if( serial_type==0 ){
+        rc = -1;
+      }else{
+        if( serial_type==7 ){
+          if( serialGet7(&aKey1[d1], &mem1) ){
+            rc = -1;  /* mem1 is a NaN */
+          }else if( mem1.u.r<pRhs->u.r ){
+            rc = -1;
+          }else if( mem1.u.r>pRhs->u.r ){
+            rc = +1;
+          }else{
+            assert( rc==0 );
+          }
+        }else{
+          sqlite3VdbeSerialGet(&aKey1[d1], serial_type, &mem1);
+          rc = sqlite3IntFloatCompare(mem1.u.i, pRhs->u.r);
+        }
+      }
+    }
+
+    /* RHS is a string */
+    else if( pRhs->flags & MEM_Str ){
+      getVarint32NR(&aKey1[idx1], serial_type);
+      testcase( serial_type==12 );
+      if( serial_type<12 ){
+        rc = -1;
+      }else if( !(serial_type & 0x01) ){
+        rc = +1;
+      }else{
+        mem1.n = (serial_type - 12) / 2;
+        testcase( (d1+mem1.n)==(unsigned)nKey1 );
+        testcase( (d1+mem1.n+1)==(unsigned)nKey1 );
+        if( (d1+mem1.n) > (unsigned)nKey1
+         || (pKeyInfo = pPKey2->pKeyInfo)->nAllField<=i
+        ){
+          pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+          return 0;                /* Corruption */
+        }else if( pKeyInfo->aColl[i] ){
+          mem1.enc = pKeyInfo->enc;
+          mem1.db = pKeyInfo->db;
+          mem1.flags = MEM_Str;
+          mem1.z = (char*)&aKey1[d1];
+          rc = vdbeCompareMemString(
+              &mem1, pRhs, pKeyInfo->aColl[i], &pPKey2->errCode
+          );
+        }else{
+          int nCmp = MIN(mem1.n, pRhs->n);
+          rc = memcmp(&aKey1[d1], pRhs->z, nCmp);
+          if( rc==0 ) rc = mem1.n - pRhs->n;
+        }
+      }
+    }
+
+    /* RHS is a blob */
+    else if( pRhs->flags & MEM_Blob ){
+      assert( (pRhs->flags & MEM_Zero)==0 || pRhs->n==0 );
+      getVarint32NR(&aKey1[idx1], serial_type);
+      testcase( serial_type==12 );
+      if( serial_type<12 || (serial_type & 0x01) ){
+        rc = -1;
+      }else{
+        int nStr = (serial_type - 12) / 2;
+        testcase( (d1+nStr)==(unsigned)nKey1 );
+        testcase( (d1+nStr+1)==(unsigned)nKey1 );
+        if( (d1+nStr) > (unsigned)nKey1 ){
+          pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+          return 0;                /* Corruption */
+        }else if( pRhs->flags & MEM_Zero ){
+          if( !isAllZero((const char*)&aKey1[d1],nStr) ){
+            rc = 1;
+          }else{
+            rc = nStr - pRhs->u.nZero;
+          }
+        }else{
+          int nCmp = MIN(nStr, pRhs->n);
+          rc = memcmp(&aKey1[d1], pRhs->z, nCmp);
+          if( rc==0 ) rc = nStr - pRhs->n;
+        }
+      }
+    }
+
+    /* RHS is null */
+    else{
+      serial_type = aKey1[idx1];
+      if( serial_type==0
+       || serial_type==10
+       || (serial_type==7 && serialGet7(&aKey1[d1], &mem1)!=0)
+      ){
+        assert( rc==0 );
+      }else{
+        rc = 1;
+      }
+    }
+
+    if( rc!=0 ){
+      int sortFlags = pPKey2->pKeyInfo->aSortFlags[i];
+      if( sortFlags ){
+        if( (sortFlags & KEYINFO_ORDER_BIGNULL)==0
+         || ((sortFlags & KEYINFO_ORDER_DESC)
+           !=(serial_type==0 || (pRhs->flags&MEM_Null)))
+        ){
+          rc = -rc;
+        }
+      }
+      assert( vdbeRecordCompareDebug(nKey1, pKey1, pPKey2, rc) );
+      assert( mem1.szMalloc==0 );  /* See comment below */
+      return rc;
+    }
+
+    i++;
+    if( i==pPKey2->nField ) break;
+    pRhs++;
+    d1 += sqlite3VdbeSerialTypeLen(serial_type);
+    if( d1>(unsigned)nKey1 ) break;
+    idx1 += sqlite3VarintLen(serial_type);
+    if( idx1>=(unsigned)szHdr1 ){
+      pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+      return 0;  /* Corrupt index */
+    }
+  }
+
+  /* No memory allocation is ever used on mem1.  Prove this using
+  ** the following assert().  If the assert() fails, it indicates a
+  ** memory leak and a need to call sqlite3VdbeMemRelease(&mem1).  */
+  assert( mem1.szMalloc==0 );
+
+  /* rc==0 here means that one or both of the keys ran out of fields and
+  ** all the fields up to that point were equal. Return the default_rc
+  ** value.  */
+  assert( CORRUPT_DB
+       || vdbeRecordCompareDebug(nKey1, pKey1, pPKey2, pPKey2->default_rc)
+       || pPKey2->pKeyInfo->db->mallocFailed
+  );
+  pPKey2->eqSeen = 1;
+  return pPKey2->default_rc;
+}
+SQLITE_PRIVATE int sqlite3VdbeRecordCompare(
+  int nKey1, const void *pKey1,   /* Left key */
+  UnpackedRecord *pPKey2          /* Right key */
+){
+  return sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, pPKey2, 0);
+}
+
+
+/*
+** This function is an optimized version of sqlite3VdbeRecordCompare()
+** that (a) the first field of pPKey2 is an integer, and (b) the
+** size-of-header varint at the start of (pKey1/nKey1) fits in a single
+** byte (i.e. is less than 128).
+**
+** To avoid concerns about buffer overreads, this routine is only used
+** on schemas where the maximum valid header size is 63 bytes or less.
+*/
+static int vdbeRecordCompareInt(
+  int nKey1, const void *pKey1, /* Left key */
+  UnpackedRecord *pPKey2        /* Right key */
+){
+  const u8 *aKey = &((const u8*)pKey1)[*(const u8*)pKey1 & 0x3F];
+  int serial_type = ((const u8*)pKey1)[1];
+  int res;
+  u32 y;
+  u64 x;
+  i64 v;
+  i64 lhs;
+
+  vdbeAssertFieldCountWithinLimits(nKey1, pKey1, pPKey2->pKeyInfo);
+  assert( (*(u8*)pKey1)<=0x3F || CORRUPT_DB );
+  switch( serial_type ){
+    case 1: { /* 1-byte signed integer */
+      lhs = ONE_BYTE_INT(aKey);
+      testcase( lhs<0 );
+      break;
+    }
+    case 2: { /* 2-byte signed integer */
+      lhs = TWO_BYTE_INT(aKey);
+      testcase( lhs<0 );
+      break;
+    }
+    case 3: { /* 3-byte signed integer */
+      lhs = THREE_BYTE_INT(aKey);
+      testcase( lhs<0 );
+      break;
+    }
+    case 4: { /* 4-byte signed integer */
+      y = FOUR_BYTE_UINT(aKey);
+      lhs = (i64)*(int*)&y;
+      testcase( lhs<0 );
+      break;
+    }
+    case 5: { /* 6-byte signed integer */
+      lhs = FOUR_BYTE_UINT(aKey+2) + (((i64)1)<<32)*TWO_BYTE_INT(aKey);
+      testcase( lhs<0 );
+      break;
+    }
+    case 6: { /* 8-byte signed integer */
+      x = FOUR_BYTE_UINT(aKey);
+      x = (x<<32) | FOUR_BYTE_UINT(aKey+4);
+      lhs = *(i64*)&x;
+      testcase( lhs<0 );
+      break;
+    }
+    case 8:
+      lhs = 0;
+      break;
+    case 9:
+      lhs = 1;
+      break;
+
+    /* This case could be removed without changing the results of running
+    ** this code. Including it causes gcc to generate a faster switch
+    ** statement (since the range of switch targets now starts at zero and
+    ** is contiguous) but does not cause any duplicate code to be generated
+    ** (as gcc is clever enough to combine the two like cases). Other
+    ** compilers might be similar.  */
+    case 0: case 7:
+      return sqlite3VdbeRecordCompare(nKey1, pKey1, pPKey2);
+
+    default:
+      return sqlite3VdbeRecordCompare(nKey1, pKey1, pPKey2);
+  }
+
+  assert( pPKey2->u.i == pPKey2->aMem[0].u.i );
+  v = pPKey2->u.i;
+  if( v>lhs ){
+    res = pPKey2->r1;
+  }else if( v<lhs ){
+    res = pPKey2->r2;
+  }else if( pPKey2->nField>1 ){
+    /* The first fields of the two keys are equal. Compare the trailing
+    ** fields.  */
+    res = sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, pPKey2, 1);
+  }else{
+    /* The first fields of the two keys are equal and there are no trailing
+    ** fields. Return pPKey2->default_rc in this case. */
+    res = pPKey2->default_rc;
+    pPKey2->eqSeen = 1;
+  }
+
+  assert( vdbeRecordCompareDebug(nKey1, pKey1, pPKey2, res) );
+  return res;
+}
+
+/*
+** This function is an optimized version of sqlite3VdbeRecordCompare()
+** that (a) the first field of pPKey2 is a string, that (b) the first field
+** uses the collation sequence BINARY and (c) that the size-of-header varint
+** at the start of (pKey1/nKey1) fits in a single byte.
+*/
+static int vdbeRecordCompareString(
+  int nKey1, const void *pKey1, /* Left key */
+  UnpackedRecord *pPKey2        /* Right key */
+){
+  const u8 *aKey1 = (const u8*)pKey1;
+  int serial_type;
+  int res;
+
+  assert( pPKey2->aMem[0].flags & MEM_Str );
+  assert( pPKey2->aMem[0].n == pPKey2->n );
+  assert( pPKey2->aMem[0].z == pPKey2->u.z );
+  vdbeAssertFieldCountWithinLimits(nKey1, pKey1, pPKey2->pKeyInfo);
+  serial_type = (signed char)(aKey1[1]);
+
+vrcs_restart:
+  if( serial_type<12 ){
+    if( serial_type<0 ){
+      sqlite3GetVarint32(&aKey1[1], (u32*)&serial_type);
+      if( serial_type>=12 ) goto vrcs_restart;
+      assert( CORRUPT_DB );
+    }
+    res = pPKey2->r1;      /* (pKey1/nKey1) is a number or a null */
+  }else if( !(serial_type & 0x01) ){
+    res = pPKey2->r2;      /* (pKey1/nKey1) is a blob */
+  }else{
+    int nCmp;
+    int nStr;
+    int szHdr = aKey1[0];
+
+    nStr = (serial_type-12) / 2;
+    if( (szHdr + nStr) > nKey1 ){
+      pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+      return 0;    /* Corruption */
+    }
+    nCmp = MIN( pPKey2->n, nStr );
+    res = memcmp(&aKey1[szHdr], pPKey2->u.z, nCmp);
+
+    if( res>0 ){
+      res = pPKey2->r2;
+    }else if( res<0 ){
+      res = pPKey2->r1;
+    }else{
+      res = nStr - pPKey2->n;
+      if( res==0 ){
+        if( pPKey2->nField>1 ){
+          res = sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, pPKey2, 1);
+        }else{
+          res = pPKey2->default_rc;
+          pPKey2->eqSeen = 1;
+        }
+      }else if( res>0 ){
+        res = pPKey2->r2;
+      }else{
+        res = pPKey2->r1;
+      }
+    }
+  }
+
+  assert( vdbeRecordCompareDebug(nKey1, pKey1, pPKey2, res)
+       || CORRUPT_DB
+       || pPKey2->pKeyInfo->db->mallocFailed
+  );
+  return res;
+}
+
+/*
+** Return a pointer to an sqlite3VdbeRecordCompare() compatible function
+** suitable for comparing serialized records to the unpacked record passed
+** as the only argument.
+*/
+SQLITE_PRIVATE RecordCompare sqlite3VdbeFindCompare(UnpackedRecord *p){
+  /* varintRecordCompareInt() and varintRecordCompareString() both assume
+  ** that the size-of-header varint that occurs at the start of each record
+  ** fits in a single byte (i.e. is 127 or less). varintRecordCompareInt()
+  ** also assumes that it is safe to overread a buffer by at least the
+  ** maximum possible legal header size plus 8 bytes. Because there is
+  ** guaranteed to be at least 74 (but not 136) bytes of padding following each
+  ** buffer passed to varintRecordCompareInt() this makes it convenient to
+  ** limit the size of the header to 64 bytes in cases where the first field
+  ** is an integer.
+  **
+  ** The easiest way to enforce this limit is to consider only records with
+  ** 13 fields or less. If the first field is an integer, the maximum legal
+  ** header size is (12*5 + 1 + 1) bytes.  */
+  if( p->pKeyInfo->nAllField<=13 ){
+    int flags = p->aMem[0].flags;
+    if( p->pKeyInfo->aSortFlags[0] ){
+      if( p->pKeyInfo->aSortFlags[0] & KEYINFO_ORDER_BIGNULL ){
+        return sqlite3VdbeRecordCompare;
+      }
+      p->r1 = 1;
+      p->r2 = -1;
+    }else{
+      p->r1 = -1;
+      p->r2 = 1;
+    }
+    if( (flags & MEM_Int) ){
+      p->u.i = p->aMem[0].u.i;
+      return vdbeRecordCompareInt;
+    }
+    testcase( flags & MEM_Real );
+    testcase( flags & MEM_Null );
+    testcase( flags & MEM_Blob );
+    if( (flags & (MEM_Real|MEM_IntReal|MEM_Null|MEM_Blob))==0
+     && p->pKeyInfo->aColl[0]==0
+    ){
+      assert( flags & MEM_Str );
+      p->u.z = p->aMem[0].z;
+      p->n = p->aMem[0].n;
+      return vdbeRecordCompareString;
+    }
+  }
+
+  return sqlite3VdbeRecordCompare;
+}
+
+/*
+** pCur points at an index entry created using the OP_MakeRecord opcode.
+** Read the rowid (the last field in the record) and store it in *rowid.
+** Return SQLITE_OK if everything works, or an error code otherwise.
+**
+** pCur might be pointing to text obtained from a corrupt database file.
+** So the content cannot be trusted.  Do appropriate checks on the content.
+*/
+SQLITE_PRIVATE int sqlite3VdbeIdxRowid(sqlite3 *db, BtCursor *pCur, i64 *rowid){
+  i64 nCellKey = 0;
+  int rc;
+  u32 szHdr;        /* Size of the header */
+  u32 typeRowid;    /* Serial type of the rowid */
+  u32 lenRowid;     /* Size of the rowid */
+  Mem m, v;
+
+  /* Get the size of the index entry.  Only indices entries of less
+  ** than 2GiB are support - anything large must be database corruption.
+  ** Any corruption is detected in sqlite3BtreeParseCellPtr(), though, so
+  ** this code can safely assume that nCellKey is 32-bits
+  */
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+  nCellKey = sqlite3BtreePayloadSize(pCur);
+  assert( (nCellKey & SQLITE_MAX_U32)==(u64)nCellKey );
+
+  /* Read in the complete content of the index entry */
+  sqlite3VdbeMemInit(&m, db, 0);
+  rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
+  if( rc ){
+    return rc;
+  }
+
+  /* The index entry must begin with a header size */
+  getVarint32NR((u8*)m.z, szHdr);
+  testcase( szHdr==3 );
+  testcase( szHdr==(u32)m.n );
+  testcase( szHdr>0x7fffffff );
+  assert( m.n>=0 );
+  if( unlikely(szHdr<3 || szHdr>(unsigned)m.n) ){
+    goto idx_rowid_corruption;
+  }
+
+  /* The last field of the index should be an integer - the ROWID.
+  ** Verify that the last entry really is an integer. */
+  getVarint32NR((u8*)&m.z[szHdr-1], typeRowid);
+  testcase( typeRowid==1 );
+  testcase( typeRowid==2 );
+  testcase( typeRowid==3 );
+  testcase( typeRowid==4 );
+  testcase( typeRowid==5 );
+  testcase( typeRowid==6 );
+  testcase( typeRowid==8 );
+  testcase( typeRowid==9 );
+  if( unlikely(typeRowid<1 || typeRowid>9 || typeRowid==7) ){
+    goto idx_rowid_corruption;
+  }
+  lenRowid = sqlite3SmallTypeSizes[typeRowid];
+  testcase( (u32)m.n==szHdr+lenRowid );
+  if( unlikely((u32)m.n<szHdr+lenRowid) ){
+    goto idx_rowid_corruption;
+  }
+
+  /* Fetch the integer off the end of the index record */
+  sqlite3VdbeSerialGet((u8*)&m.z[m.n-lenRowid], typeRowid, &v);
+  *rowid = v.u.i;
+  sqlite3VdbeMemReleaseMalloc(&m);
+  return SQLITE_OK;
+
+  /* Jump here if database corruption is detected after m has been
+  ** allocated.  Free the m object and return SQLITE_CORRUPT. */
+idx_rowid_corruption:
+  testcase( m.szMalloc!=0 );
+  sqlite3VdbeMemReleaseMalloc(&m);
+  return SQLITE_CORRUPT_BKPT;
+}
+
+/*
+** Compare the key of the index entry that cursor pC is pointing to against
+** the key string in pUnpacked.  Write into *pRes a number
+** that is negative, zero, or positive if pC is less than, equal to,
+** or greater than pUnpacked.  Return SQLITE_OK on success.
+**
+** pUnpacked is either created without a rowid or is truncated so that it
+** omits the rowid at the end.  The rowid at the end of the index entry
+** is ignored as well.  Hence, this routine only compares the prefixes
+** of the keys prior to the final rowid, not the entire key.
+*/
+SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(
+  sqlite3 *db,                     /* Database connection */
+  VdbeCursor *pC,                  /* The cursor to compare against */
+  UnpackedRecord *pUnpacked,       /* Unpacked version of key */
+  int *res                         /* Write the comparison result here */
+){
+  i64 nCellKey = 0;
+  int rc;
+  BtCursor *pCur;
+  Mem m;
+
+  assert( pC->eCurType==CURTYPE_BTREE );
+  pCur = pC->uc.pCursor;
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+  nCellKey = sqlite3BtreePayloadSize(pCur);
+  /* nCellKey will always be between 0 and 0xffffffff because of the way
+  ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
+  if( nCellKey<=0 || nCellKey>0x7fffffff ){
+    *res = 0;
+    return SQLITE_CORRUPT_BKPT;
+  }
+  sqlite3VdbeMemInit(&m, db, 0);
+  rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
+  if( rc ){
+    return rc;
+  }
+  *res = sqlite3VdbeRecordCompareWithSkip(m.n, m.z, pUnpacked, 0);
+  sqlite3VdbeMemReleaseMalloc(&m);
+  return SQLITE_OK;
+}
+
+/*
+** This routine sets the value to be returned by subsequent calls to
+** sqlite3_changes() on the database handle 'db'.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetChanges(sqlite3 *db, i64 nChange){
+  assert( sqlite3_mutex_held(db->mutex) );
+  db->nChange = nChange;
+  db->nTotalChange += nChange;
+}
+
+/*
+** Set a flag in the vdbe to update the change counter when it is finalised
+** or reset.
+*/
+SQLITE_PRIVATE void sqlite3VdbeCountChanges(Vdbe *v){
+  v->changeCntOn = 1;
+}
+
+/*
+** Mark every prepared statement associated with a database connection
+** as expired.
+**
+** An expired statement means that recompilation of the statement is
+** recommend.  Statements expire when things happen that make their
+** programs obsolete.  Removing user-defined functions or collating
+** sequences, or changing an authorization function are the types of
+** things that make prepared statements obsolete.
+**
+** If iCode is 1, then expiration is advisory.  The statement should
+** be reprepared before being restarted, but if it is already running
+** it is allowed to run to completion.
+**
+** Internally, this function just sets the Vdbe.expired flag on all
+** prepared statements.  The flag is set to 1 for an immediate expiration
+** and set to 2 for an advisory expiration.
+*/
+SQLITE_PRIVATE void sqlite3ExpirePreparedStatements(sqlite3 *db, int iCode){
+  Vdbe *p;
+  for(p = db->pVdbe; p; p=p->pVNext){
+    p->expired = iCode+1;
+  }
+}
+
+/*
+** Return the database associated with the Vdbe.
+*/
+SQLITE_PRIVATE sqlite3 *sqlite3VdbeDb(Vdbe *v){
+  return v->db;
+}
+
+/*
+** Return the SQLITE_PREPARE flags for a Vdbe.
+*/
+SQLITE_PRIVATE u8 sqlite3VdbePrepareFlags(Vdbe *v){
+  return v->prepFlags;
+}
+
+/*
+** Return a pointer to an sqlite3_value structure containing the value bound
+** parameter iVar of VM v. Except, if the value is an SQL NULL, return
+** 0 instead. Unless it is NULL, apply affinity aff (one of the SQLITE_AFF_*
+** constants) to the value before returning it.
+**
+** The returned value must be freed by the caller using sqlite3ValueFree().
+*/
+SQLITE_PRIVATE sqlite3_value *sqlite3VdbeGetBoundValue(Vdbe *v, int iVar, u8 aff){
+  assert( iVar>0 );
+  if( v ){
+    Mem *pMem = &v->aVar[iVar-1];
+    assert( (v->db->flags & SQLITE_EnableQPSG)==0
+         || (v->db->mDbFlags & DBFLAG_InternalFunc)!=0 );
+    if( 0==(pMem->flags & MEM_Null) ){
+      sqlite3_value *pRet = sqlite3ValueNew(v->db);
+      if( pRet ){
+        sqlite3VdbeMemCopy((Mem *)pRet, pMem);
+        sqlite3ValueApplyAffinity(pRet, aff, SQLITE_UTF8);
+      }
+      return pRet;
+    }
+  }
+  return 0;
+}
+
+/*
+** Configure SQL variable iVar so that binding a new value to it signals
+** to sqlite3_reoptimize() that re-preparing the statement may result
+** in a better query plan.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetVarmask(Vdbe *v, int iVar){
+  assert( iVar>0 );
+  assert( (v->db->flags & SQLITE_EnableQPSG)==0
+       || (v->db->mDbFlags & DBFLAG_InternalFunc)!=0 );
+  if( iVar>=32 ){
+    v->expmask |= 0x80000000;
+  }else{
+    v->expmask |= ((u32)1 << (iVar-1));
+  }
+}
+
+/*
+** Cause a function to throw an error if it was call from OP_PureFunc
+** rather than OP_Function.
+**
+** OP_PureFunc means that the function must be deterministic, and should
+** throw an error if it is given inputs that would make it non-deterministic.
+** This routine is invoked by date/time functions that use non-deterministic
+** features such as 'now'.
+*/
+SQLITE_PRIVATE int sqlite3NotPureFunc(sqlite3_context *pCtx){
+  const VdbeOp *pOp;
+#ifdef SQLITE_ENABLE_STAT4
+  if( pCtx->pVdbe==0 ) return 1;
+#endif
+  pOp = pCtx->pVdbe->aOp + pCtx->iOp;
+  if( pOp->opcode==OP_PureFunc ){
+    const char *zContext;
+    char *zMsg;
+    if( pOp->p5 & NC_IsCheck ){
+      zContext = "a CHECK constraint";
+    }else if( pOp->p5 & NC_GenCol ){
+      zContext = "a generated column";
+    }else{
+      zContext = "an index";
+    }
+    zMsg = sqlite3_mprintf("non-deterministic use of %s() in %s",
+                           pCtx->pFunc->zName, zContext);
+    sqlite3_result_error(pCtx, zMsg, -1);
+    sqlite3_free(zMsg);
+    return 0;
+  }
+  return 1;
+}
+
+#if defined(SQLITE_ENABLE_CURSOR_HINTS) && defined(SQLITE_DEBUG)
+/*
+** This Walker callback is used to help verify that calls to
+** sqlite3BtreeCursorHint() with opcode BTREE_HINT_RANGE have
+** byte-code register values correctly initialized.
+*/
+SQLITE_PRIVATE int sqlite3CursorRangeHintExprCheck(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_REGISTER ){
+    assert( (pWalker->u.aMem[pExpr->iTable].flags & MEM_Undefined)==0 );
+  }
+  return WRC_Continue;
+}
+#endif /* SQLITE_ENABLE_CURSOR_HINTS && SQLITE_DEBUG */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Transfer error message text from an sqlite3_vtab.zErrMsg (text stored
+** in memory obtained from sqlite3_malloc) into a Vdbe.zErrMsg (text stored
+** in memory obtained from sqlite3DbMalloc).
+*/
+SQLITE_PRIVATE void sqlite3VtabImportErrmsg(Vdbe *p, sqlite3_vtab *pVtab){
+  if( pVtab->zErrMsg ){
+    sqlite3 *db = p->db;
+    sqlite3DbFree(db, p->zErrMsg);
+    p->zErrMsg = sqlite3DbStrDup(db, pVtab->zErrMsg);
+    sqlite3_free(pVtab->zErrMsg);
+    pVtab->zErrMsg = 0;
+  }
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+
+/*
+** If the second argument is not NULL, release any allocations associated
+** with the memory cells in the p->aMem[] array. Also free the UnpackedRecord
+** structure itself, using sqlite3DbFree().
+**
+** This function is used to free UnpackedRecord structures allocated by
+** the vdbeUnpackRecord() function found in vdbeapi.c.
+*/
+static void vdbeFreeUnpacked(sqlite3 *db, int nField, UnpackedRecord *p){
+  assert( db!=0 );
+  if( p ){
+    int i;
+    for(i=0; i<nField; i++){
+      Mem *pMem = &p->aMem[i];
+      if( pMem->zMalloc ) sqlite3VdbeMemReleaseMalloc(pMem);
+    }
+    sqlite3DbNNFreeNN(db, p);
+  }
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** Invoke the pre-update hook. If this is an UPDATE or DELETE pre-update call,
+** then cursor passed as the second argument should point to the row about
+** to be update or deleted. If the application calls sqlite3_preupdate_old(),
+** the required value will be read from the row the cursor points to.
+*/
+SQLITE_PRIVATE void sqlite3VdbePreUpdateHook(
+  Vdbe *v,                        /* Vdbe pre-update hook is invoked by */
+  VdbeCursor *pCsr,               /* Cursor to grab old.* values from */
+  int op,                         /* SQLITE_INSERT, UPDATE or DELETE */
+  const char *zDb,                /* Database name */
+  Table *pTab,                    /* Modified table */
+  i64 iKey1,                      /* Initial key value */
+  int iReg,                       /* Register for new.* record */
+  int iBlobWrite
+){
+  sqlite3 *db = v->db;
+  i64 iKey2;
+  PreUpdate preupdate;
+  const char *zTbl = pTab->zName;
+  static const u8 fakeSortOrder = 0;
+#ifdef SQLITE_DEBUG
+  int nRealCol;
+  if( pTab->tabFlags & TF_WithoutRowid ){
+    nRealCol = sqlite3PrimaryKeyIndex(pTab)->nColumn;
+  }else if( pTab->tabFlags & TF_HasVirtual ){
+    nRealCol = pTab->nNVCol;
+  }else{
+    nRealCol = pTab->nCol;
+  }
+#endif
+
+  assert( db->pPreUpdate==0 );
+  memset(&preupdate, 0, sizeof(PreUpdate));
+  if( HasRowid(pTab)==0 ){
+    iKey1 = iKey2 = 0;
+    preupdate.pPk = sqlite3PrimaryKeyIndex(pTab);
+  }else{
+    if( op==SQLITE_UPDATE ){
+      iKey2 = v->aMem[iReg].u.i;
+    }else{
+      iKey2 = iKey1;
+    }
+  }
+
+  assert( pCsr!=0 );
+  assert( pCsr->eCurType==CURTYPE_BTREE );
+  assert( pCsr->nField==nRealCol
+       || (pCsr->nField==nRealCol+1 && op==SQLITE_DELETE && iReg==-1)
+  );
+
+  preupdate.v = v;
+  preupdate.pCsr = pCsr;
+  preupdate.op = op;
+  preupdate.iNewReg = iReg;
+  preupdate.keyinfo.db = db;
+  preupdate.keyinfo.enc = ENC(db);
+  preupdate.keyinfo.nKeyField = pTab->nCol;
+  preupdate.keyinfo.aSortFlags = (u8*)&fakeSortOrder;
+  preupdate.iKey1 = iKey1;
+  preupdate.iKey2 = iKey2;
+  preupdate.pTab = pTab;
+  preupdate.iBlobWrite = iBlobWrite;
+
+  db->pPreUpdate = &preupdate;
+  db->xPreUpdateCallback(db->pPreUpdateArg, db, op, zDb, zTbl, iKey1, iKey2);
+  db->pPreUpdate = 0;
+  sqlite3DbFree(db, preupdate.aRecord);
+  vdbeFreeUnpacked(db, preupdate.keyinfo.nKeyField+1, preupdate.pUnpacked);
+  vdbeFreeUnpacked(db, preupdate.keyinfo.nKeyField+1, preupdate.pNewUnpacked);
+  sqlite3VdbeMemRelease(&preupdate.oldipk);
+  if( preupdate.aNew ){
+    int i;
+    for(i=0; i<pCsr->nField; i++){
+      sqlite3VdbeMemRelease(&preupdate.aNew[i]);
+    }
+    sqlite3DbNNFreeNN(db, preupdate.aNew);
+  }
+  if( preupdate.apDflt ){
+    int i;
+    for(i=0; i<pTab->nCol; i++){
+      sqlite3ValueFree(preupdate.apDflt[i]);
+    }
+    sqlite3DbFree(db, preupdate.apDflt);
+  }
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+/************** End of vdbeaux.c *********************************************/
+/************** Begin file vdbeapi.c *****************************************/
+/*
+** 2004 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code use to implement APIs that are part of the
+** VDBE.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+/* #include "opcodes.h" */
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Return TRUE (non-zero) of the statement supplied as an argument needs
+** to be recompiled.  A statement needs to be recompiled whenever the
+** execution environment changes in a way that would alter the program
+** that sqlite3_prepare() generates.  For example, if new functions or
+** collating sequences are registered or if an authorizer function is
+** added or changed.
+*/
+SQLITE_API int sqlite3_expired(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe*)pStmt;
+  return p==0 || p->expired;
+}
+#endif
+
+/*
+** Check on a Vdbe to make sure it has not been finalized.  Log
+** an error and return true if it has been finalized (or is otherwise
+** invalid).  Return false if it is ok.
+*/
+static int vdbeSafety(Vdbe *p){
+  if( p->db==0 ){
+    sqlite3_log(SQLITE_MISUSE, "API called with finalized prepared statement");
+    return 1;
+  }else{
+    return 0;
+  }
+}
+static int vdbeSafetyNotNull(Vdbe *p){
+  if( p==0 ){
+    sqlite3_log(SQLITE_MISUSE, "API called with NULL prepared statement");
+    return 1;
+  }else{
+    return vdbeSafety(p);
+  }
+}
+
+#ifndef SQLITE_OMIT_TRACE
+/*
+** Invoke the profile callback.  This routine is only called if we already
+** know that the profile callback is defined and needs to be invoked.
+*/
+static SQLITE_NOINLINE void invokeProfileCallback(sqlite3 *db, Vdbe *p){
+  sqlite3_int64 iNow;
+  sqlite3_int64 iElapse;
+  assert( p->startTime>0 );
+  assert( db->init.busy==0 );
+  assert( p->zSql!=0 );
+  sqlite3OsCurrentTimeInt64(db->pVfs, &iNow);
+  iElapse = (iNow - p->startTime)*1000000;
+#ifndef SQLITE_OMIT_DEPRECATED
+  if( db->xProfile ){
+    db->xProfile(db->pProfileArg, p->zSql, iElapse);
+  }
+#endif
+  if( db->mTrace & SQLITE_TRACE_PROFILE ){
+    db->trace.xV2(SQLITE_TRACE_PROFILE, db->pTraceArg, p, (void*)&iElapse);
+  }
+  p->startTime = 0;
+}
+/*
+** The checkProfileCallback(DB,P) macro checks to see if a profile callback
+** is needed, and it invokes the callback if it is needed.
+*/
+# define checkProfileCallback(DB,P) \
+   if( ((P)->startTime)>0 ){ invokeProfileCallback(DB,P); }
+#else
+# define checkProfileCallback(DB,P)  /*no-op*/
+#endif
+
+/*
+** The following routine destroys a virtual machine that is created by
+** the sqlite3_compile() routine. The integer returned is an SQLITE_
+** success/failure code that describes the result of executing the virtual
+** machine.
+**
+** This routine sets the error code and string returned by
+** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
+*/
+SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt){
+  int rc;
+  if( pStmt==0 ){
+    /* IMPLEMENTATION-OF: R-57228-12904 Invoking sqlite3_finalize() on a NULL
+    ** pointer is a harmless no-op. */
+    rc = SQLITE_OK;
+  }else{
+    Vdbe *v = (Vdbe*)pStmt;
+    sqlite3 *db = v->db;
+    if( vdbeSafety(v) ) return SQLITE_MISUSE_BKPT;
+    sqlite3_mutex_enter(db->mutex);
+    checkProfileCallback(db, v);
+    assert( v->eVdbeState>=VDBE_READY_STATE );
+    rc = sqlite3VdbeReset(v);
+    sqlite3VdbeDelete(v);
+    rc = sqlite3ApiExit(db, rc);
+    sqlite3LeaveMutexAndCloseZombie(db);
+  }
+  return rc;
+}
+
+/*
+** Terminate the current execution of an SQL statement and reset it
+** back to its starting state so that it can be reused. A success code from
+** the prior execution is returned.
+**
+** This routine sets the error code and string returned by
+** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
+*/
+SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt){
+  int rc;
+  if( pStmt==0 ){
+    rc = SQLITE_OK;
+  }else{
+    Vdbe *v = (Vdbe*)pStmt;
+    sqlite3 *db = v->db;
+    sqlite3_mutex_enter(db->mutex);
+    checkProfileCallback(db, v);
+    rc = sqlite3VdbeReset(v);
+    sqlite3VdbeRewind(v);
+    assert( (rc & (db->errMask))==rc );
+    rc = sqlite3ApiExit(db, rc);
+    sqlite3_mutex_leave(db->mutex);
+  }
+  return rc;
+}
+
+/*
+** Set all the parameters in the compiled SQL statement to NULL.
+*/
+SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt *pStmt){
+  int i;
+  int rc = SQLITE_OK;
+  Vdbe *p = (Vdbe*)pStmt;
+#if SQLITE_THREADSAFE
+  sqlite3_mutex *mutex;
+#endif
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pStmt==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+#if SQLITE_THREADSAFE
+  mutex = p->db->mutex;
+#endif
+  sqlite3_mutex_enter(mutex);
+  for(i=0; i<p->nVar; i++){
+    sqlite3VdbeMemRelease(&p->aVar[i]);
+    p->aVar[i].flags = MEM_Null;
+  }
+  assert( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || p->expmask==0 );
+  if( p->expmask ){
+    p->expired = 1;
+  }
+  sqlite3_mutex_leave(mutex);
+  return rc;
+}
+
+
+/**************************** sqlite3_value_  *******************************
+** The following routines extract information from a Mem or sqlite3_value
+** structure.
+*/
+SQLITE_API const void *sqlite3_value_blob(sqlite3_value *pVal){
+  Mem *p = (Mem*)pVal;
+  if( p->flags & (MEM_Blob|MEM_Str) ){
+    if( ExpandBlob(p)!=SQLITE_OK ){
+      assert( p->flags==MEM_Null && p->z==0 );
+      return 0;
+    }
+    p->flags |= MEM_Blob;
+    return p->n ? p->z : 0;
+  }else{
+    return sqlite3_value_text(pVal);
+  }
+}
+SQLITE_API int sqlite3_value_bytes(sqlite3_value *pVal){
+  return sqlite3ValueBytes(pVal, SQLITE_UTF8);
+}
+SQLITE_API int sqlite3_value_bytes16(sqlite3_value *pVal){
+  return sqlite3ValueBytes(pVal, SQLITE_UTF16NATIVE);
+}
+SQLITE_API double sqlite3_value_double(sqlite3_value *pVal){
+  return sqlite3VdbeRealValue((Mem*)pVal);
+}
+SQLITE_API int sqlite3_value_int(sqlite3_value *pVal){
+  return (int)sqlite3VdbeIntValue((Mem*)pVal);
+}
+SQLITE_API sqlite_int64 sqlite3_value_int64(sqlite3_value *pVal){
+  return sqlite3VdbeIntValue((Mem*)pVal);
+}
+SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value *pVal){
+  Mem *pMem = (Mem*)pVal;
+  return ((pMem->flags & MEM_Subtype) ? pMem->eSubtype : 0);
+}
+SQLITE_API void *sqlite3_value_pointer(sqlite3_value *pVal, const char *zPType){
+  Mem *p = (Mem*)pVal;
+  if( (p->flags&(MEM_TypeMask|MEM_Term|MEM_Subtype)) ==
+                 (MEM_Null|MEM_Term|MEM_Subtype)
+   && zPType!=0
+   && p->eSubtype=='p'
+   && strcmp(p->u.zPType, zPType)==0
+  ){
+    return (void*)p->z;
+  }else{
+    return 0;
+  }
+}
+SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value *pVal){
+  return (const unsigned char *)sqlite3ValueText(pVal, SQLITE_UTF8);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_value_text16(sqlite3_value* pVal){
+  return sqlite3ValueText(pVal, SQLITE_UTF16NATIVE);
+}
+SQLITE_API const void *sqlite3_value_text16be(sqlite3_value *pVal){
+  return sqlite3ValueText(pVal, SQLITE_UTF16BE);
+}
+SQLITE_API const void *sqlite3_value_text16le(sqlite3_value *pVal){
+  return sqlite3ValueText(pVal, SQLITE_UTF16LE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+/* EVIDENCE-OF: R-12793-43283 Every value in SQLite has one of five
+** fundamental datatypes: 64-bit signed integer 64-bit IEEE floating
+** point number string BLOB NULL
+*/
+SQLITE_API int sqlite3_value_type(sqlite3_value* pVal){
+  static const u8 aType[] = {
+     SQLITE_BLOB,     /* 0x00 (not possible) */
+     SQLITE_NULL,     /* 0x01 NULL */
+     SQLITE_TEXT,     /* 0x02 TEXT */
+     SQLITE_NULL,     /* 0x03 (not possible) */
+     SQLITE_INTEGER,  /* 0x04 INTEGER */
+     SQLITE_NULL,     /* 0x05 (not possible) */
+     SQLITE_INTEGER,  /* 0x06 INTEGER + TEXT */
+     SQLITE_NULL,     /* 0x07 (not possible) */
+     SQLITE_FLOAT,    /* 0x08 FLOAT */
+     SQLITE_NULL,     /* 0x09 (not possible) */
+     SQLITE_FLOAT,    /* 0x0a FLOAT + TEXT */
+     SQLITE_NULL,     /* 0x0b (not possible) */
+     SQLITE_INTEGER,  /* 0x0c (not possible) */
+     SQLITE_NULL,     /* 0x0d (not possible) */
+     SQLITE_INTEGER,  /* 0x0e (not possible) */
+     SQLITE_NULL,     /* 0x0f (not possible) */
+     SQLITE_BLOB,     /* 0x10 BLOB */
+     SQLITE_NULL,     /* 0x11 (not possible) */
+     SQLITE_TEXT,     /* 0x12 (not possible) */
+     SQLITE_NULL,     /* 0x13 (not possible) */
+     SQLITE_INTEGER,  /* 0x14 INTEGER + BLOB */
+     SQLITE_NULL,     /* 0x15 (not possible) */
+     SQLITE_INTEGER,  /* 0x16 (not possible) */
+     SQLITE_NULL,     /* 0x17 (not possible) */
+     SQLITE_FLOAT,    /* 0x18 FLOAT + BLOB */
+     SQLITE_NULL,     /* 0x19 (not possible) */
+     SQLITE_FLOAT,    /* 0x1a (not possible) */
+     SQLITE_NULL,     /* 0x1b (not possible) */
+     SQLITE_INTEGER,  /* 0x1c (not possible) */
+     SQLITE_NULL,     /* 0x1d (not possible) */
+     SQLITE_INTEGER,  /* 0x1e (not possible) */
+     SQLITE_NULL,     /* 0x1f (not possible) */
+     SQLITE_FLOAT,    /* 0x20 INTREAL */
+     SQLITE_NULL,     /* 0x21 (not possible) */
+     SQLITE_FLOAT,    /* 0x22 INTREAL + TEXT */
+     SQLITE_NULL,     /* 0x23 (not possible) */
+     SQLITE_FLOAT,    /* 0x24 (not possible) */
+     SQLITE_NULL,     /* 0x25 (not possible) */
+     SQLITE_FLOAT,    /* 0x26 (not possible) */
+     SQLITE_NULL,     /* 0x27 (not possible) */
+     SQLITE_FLOAT,    /* 0x28 (not possible) */
+     SQLITE_NULL,     /* 0x29 (not possible) */
+     SQLITE_FLOAT,    /* 0x2a (not possible) */
+     SQLITE_NULL,     /* 0x2b (not possible) */
+     SQLITE_FLOAT,    /* 0x2c (not possible) */
+     SQLITE_NULL,     /* 0x2d (not possible) */
+     SQLITE_FLOAT,    /* 0x2e (not possible) */
+     SQLITE_NULL,     /* 0x2f (not possible) */
+     SQLITE_BLOB,     /* 0x30 (not possible) */
+     SQLITE_NULL,     /* 0x31 (not possible) */
+     SQLITE_TEXT,     /* 0x32 (not possible) */
+     SQLITE_NULL,     /* 0x33 (not possible) */
+     SQLITE_FLOAT,    /* 0x34 (not possible) */
+     SQLITE_NULL,     /* 0x35 (not possible) */
+     SQLITE_FLOAT,    /* 0x36 (not possible) */
+     SQLITE_NULL,     /* 0x37 (not possible) */
+     SQLITE_FLOAT,    /* 0x38 (not possible) */
+     SQLITE_NULL,     /* 0x39 (not possible) */
+     SQLITE_FLOAT,    /* 0x3a (not possible) */
+     SQLITE_NULL,     /* 0x3b (not possible) */
+     SQLITE_FLOAT,    /* 0x3c (not possible) */
+     SQLITE_NULL,     /* 0x3d (not possible) */
+     SQLITE_FLOAT,    /* 0x3e (not possible) */
+     SQLITE_NULL,     /* 0x3f (not possible) */
+  };
+#ifdef SQLITE_DEBUG
+  {
+    int eType = SQLITE_BLOB;
+    if( pVal->flags & MEM_Null ){
+      eType = SQLITE_NULL;
+    }else if( pVal->flags & (MEM_Real|MEM_IntReal) ){
+      eType = SQLITE_FLOAT;
+    }else if( pVal->flags & MEM_Int ){
+      eType = SQLITE_INTEGER;
+    }else if( pVal->flags & MEM_Str ){
+      eType = SQLITE_TEXT;
+    }
+    assert( eType == aType[pVal->flags&MEM_AffMask] );
+  }
+#endif
+  return aType[pVal->flags&MEM_AffMask];
+}
+SQLITE_API int sqlite3_value_encoding(sqlite3_value *pVal){
+  return pVal->enc;
+}
+
+/* Return true if a parameter to xUpdate represents an unchanged column */
+SQLITE_API int sqlite3_value_nochange(sqlite3_value *pVal){
+  return (pVal->flags&(MEM_Null|MEM_Zero))==(MEM_Null|MEM_Zero);
+}
+
+/* Return true if a parameter value originated from an sqlite3_bind() */
+SQLITE_API int sqlite3_value_frombind(sqlite3_value *pVal){
+  return (pVal->flags&MEM_FromBind)!=0;
+}
+
+/* Make a copy of an sqlite3_value object
+*/
+SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value *pOrig){
+  sqlite3_value *pNew;
+  if( pOrig==0 ) return 0;
+  pNew = sqlite3_malloc( sizeof(*pNew) );
+  if( pNew==0 ) return 0;
+  memset(pNew, 0, sizeof(*pNew));
+  memcpy(pNew, pOrig, MEMCELLSIZE);
+  pNew->flags &= ~MEM_Dyn;
+  pNew->db = 0;
+  if( pNew->flags&(MEM_Str|MEM_Blob) ){
+    pNew->flags &= ~(MEM_Static|MEM_Dyn);
+    pNew->flags |= MEM_Ephem;
+    if( sqlite3VdbeMemMakeWriteable(pNew)!=SQLITE_OK ){
+      sqlite3ValueFree(pNew);
+      pNew = 0;
+    }
+  }else if( pNew->flags & MEM_Null ){
+    /* Do not duplicate pointer values */
+    pNew->flags &= ~(MEM_Term|MEM_Subtype);
+  }
+  return pNew;
+}
+
+/* Destroy an sqlite3_value object previously obtained from
+** sqlite3_value_dup().
+*/
+SQLITE_API void sqlite3_value_free(sqlite3_value *pOld){
+  sqlite3ValueFree(pOld);
+}
+
+
+/**************************** sqlite3_result_  *******************************
+** The following routines are used by user-defined functions to specify
+** the function result.
+**
+** The setStrOrError() function calls sqlite3VdbeMemSetStr() to store the
+** result as a string or blob.  Appropriate errors are set if the string/blob
+** is too big or if an OOM occurs.
+**
+** The invokeValueDestructor(P,X) routine invokes destructor function X()
+** on value P if P is not going to be used and need to be destroyed.
+*/
+static void setResultStrOrError(
+  sqlite3_context *pCtx,  /* Function context */
+  const char *z,          /* String pointer */
+  int n,                  /* Bytes in string, or negative */
+  u8 enc,                 /* Encoding of z.  0 for BLOBs */
+  void (*xDel)(void*)     /* Destructor function */
+){
+  Mem *pOut = pCtx->pOut;
+  int rc = sqlite3VdbeMemSetStr(pOut, z, n, enc, xDel);
+  if( rc ){
+    if( rc==SQLITE_TOOBIG ){
+      sqlite3_result_error_toobig(pCtx);
+    }else{
+      /* The only errors possible from sqlite3VdbeMemSetStr are
+      ** SQLITE_TOOBIG and SQLITE_NOMEM */
+      assert( rc==SQLITE_NOMEM );
+      sqlite3_result_error_nomem(pCtx);
+    }
+    return;
+  }
+  sqlite3VdbeChangeEncoding(pOut, pCtx->enc);
+  if( sqlite3VdbeMemTooBig(pOut) ){
+    sqlite3_result_error_toobig(pCtx);
+  }
+}
+static int invokeValueDestructor(
+  const void *p,             /* Value to destroy */
+  void (*xDel)(void*),       /* The destructor */
+  sqlite3_context *pCtx      /* Set a SQLITE_TOOBIG error if not NULL */
+){
+  assert( xDel!=SQLITE_DYNAMIC );
+  if( xDel==0 ){
+    /* noop */
+  }else if( xDel==SQLITE_TRANSIENT ){
+    /* noop */
+  }else{
+    xDel((void*)p);
+  }
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx!=0 ){
+    sqlite3_result_error_toobig(pCtx);
+  }
+#else
+  assert( pCtx!=0 );
+  sqlite3_result_error_toobig(pCtx);
+#endif
+  return SQLITE_TOOBIG;
+}
+SQLITE_API void sqlite3_result_blob(
+  sqlite3_context *pCtx,
+  const void *z,
+  int n,
+  void (*xDel)(void *)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 || n<0 ){
+    invokeValueDestructor(z, xDel, pCtx);
+    return;
+  }
+#endif
+  assert( n>=0 );
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n, 0, xDel);
+}
+SQLITE_API void sqlite3_result_blob64(
+  sqlite3_context *pCtx,
+  const void *z,
+  sqlite3_uint64 n,
+  void (*xDel)(void *)
+){
+  assert( xDel!=SQLITE_DYNAMIC );
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ){
+    invokeValueDestructor(z, xDel, 0);
+    return;
+  }
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  if( n>0x7fffffff ){
+    (void)invokeValueDestructor(z, xDel, pCtx);
+  }else{
+    setResultStrOrError(pCtx, z, (int)n, 0, xDel);
+  }
+}
+SQLITE_API void sqlite3_result_double(sqlite3_context *pCtx, double rVal){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetDouble(pCtx->pOut, rVal);
+}
+SQLITE_API void sqlite3_result_error(sqlite3_context *pCtx, const char *z, int n){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  pCtx->isError = SQLITE_ERROR;
+  sqlite3VdbeMemSetStr(pCtx->pOut, z, n, SQLITE_UTF8, SQLITE_TRANSIENT);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API void sqlite3_result_error16(sqlite3_context *pCtx, const void *z, int n){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  pCtx->isError = SQLITE_ERROR;
+  sqlite3VdbeMemSetStr(pCtx->pOut, z, n, SQLITE_UTF16NATIVE, SQLITE_TRANSIENT);
+}
+#endif
+SQLITE_API void sqlite3_result_int(sqlite3_context *pCtx, int iVal){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetInt64(pCtx->pOut, (i64)iVal);
+}
+SQLITE_API void sqlite3_result_int64(sqlite3_context *pCtx, i64 iVal){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetInt64(pCtx->pOut, iVal);
+}
+SQLITE_API void sqlite3_result_null(sqlite3_context *pCtx){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetNull(pCtx->pOut);
+}
+SQLITE_API void sqlite3_result_pointer(
+  sqlite3_context *pCtx,
+  void *pPtr,
+  const char *zPType,
+  void (*xDestructor)(void*)
+){
+  Mem *pOut;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ){
+    invokeValueDestructor(pPtr, xDestructor, 0);
+    return;
+  }
+#endif
+  pOut = pCtx->pOut;
+  assert( sqlite3_mutex_held(pOut->db->mutex) );
+  sqlite3VdbeMemRelease(pOut);
+  pOut->flags = MEM_Null;
+  sqlite3VdbeMemSetPointer(pOut, pPtr, zPType, xDestructor);
+}
+SQLITE_API void sqlite3_result_subtype(sqlite3_context *pCtx, unsigned int eSubtype){
+  Mem *pOut;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+#if defined(SQLITE_STRICT_SUBTYPE) && SQLITE_STRICT_SUBTYPE+0!=0
+  if( pCtx->pFunc!=0
+   && (pCtx->pFunc->funcFlags & SQLITE_RESULT_SUBTYPE)==0
+  ){
+    char zErr[200];
+    sqlite3_snprintf(sizeof(zErr), zErr,
+                     "misuse of sqlite3_result_subtype() by %s()",
+                     pCtx->pFunc->zName);
+    sqlite3_result_error(pCtx, zErr, -1);
+    return;
+  }
+#endif /* SQLITE_STRICT_SUBTYPE */
+  pOut = pCtx->pOut;
+  assert( sqlite3_mutex_held(pOut->db->mutex) );
+  pOut->eSubtype = eSubtype & 0xff;
+  pOut->flags |= MEM_Subtype;
+}
+SQLITE_API void sqlite3_result_text(
+  sqlite3_context *pCtx,
+  const char *z,
+  int n,
+  void (*xDel)(void *)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ){
+    invokeValueDestructor(z, xDel, 0);
+    return;
+  }
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n, SQLITE_UTF8, xDel);
+}
+SQLITE_API void sqlite3_result_text64(
+  sqlite3_context *pCtx,
+  const char *z,
+  sqlite3_uint64 n,
+  void (*xDel)(void *),
+  unsigned char enc
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ){
+    invokeValueDestructor(z, xDel, 0);
+    return;
+  }
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  assert( xDel!=SQLITE_DYNAMIC );
+  if( enc!=SQLITE_UTF8 ){
+    if( enc==SQLITE_UTF16 ) enc = SQLITE_UTF16NATIVE;
+    n &= ~(u64)1;
+  }
+  if( n>0x7fffffff ){
+    (void)invokeValueDestructor(z, xDel, pCtx);
+  }else{
+    setResultStrOrError(pCtx, z, (int)n, enc, xDel);
+    sqlite3VdbeMemZeroTerminateIfAble(pCtx->pOut);
+  }
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API void sqlite3_result_text16(
+  sqlite3_context *pCtx,
+  const void *z,
+  int n,
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n & ~(u64)1, SQLITE_UTF16NATIVE, xDel);
+}
+SQLITE_API void sqlite3_result_text16be(
+  sqlite3_context *pCtx,
+  const void *z,
+  int n,
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n & ~(u64)1, SQLITE_UTF16BE, xDel);
+}
+SQLITE_API void sqlite3_result_text16le(
+  sqlite3_context *pCtx,
+  const void *z,
+  int n,
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n & ~(u64)1, SQLITE_UTF16LE, xDel);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API void sqlite3_result_value(sqlite3_context *pCtx, sqlite3_value *pValue){
+  Mem *pOut;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+  if( pValue==0 ){
+    sqlite3_result_null(pCtx);
+    return;
+  }
+#endif
+  pOut = pCtx->pOut;
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemCopy(pOut, pValue);
+  sqlite3VdbeChangeEncoding(pOut, pCtx->enc);
+  if( sqlite3VdbeMemTooBig(pOut) ){
+    sqlite3_result_error_toobig(pCtx);
+  }
+}
+SQLITE_API void sqlite3_result_zeroblob(sqlite3_context *pCtx, int n){
+  sqlite3_result_zeroblob64(pCtx, n>0 ? n : 0);
+}
+SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context *pCtx, u64 n){
+  Mem *pOut;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  pOut = pCtx->pOut;
+  assert( sqlite3_mutex_held(pOut->db->mutex) );
+  if( n>(u64)pOut->db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    sqlite3_result_error_toobig(pCtx);
+    return SQLITE_TOOBIG;
+  }
+#ifndef SQLITE_OMIT_INCRBLOB
+  sqlite3VdbeMemSetZeroBlob(pCtx->pOut, (int)n);
+  return SQLITE_OK;
+#else
+  return sqlite3VdbeMemSetZeroBlob(pCtx->pOut, (int)n);
+#endif
+}
+SQLITE_API void sqlite3_result_error_code(sqlite3_context *pCtx, int errCode){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  pCtx->isError = errCode ? errCode : -1;
+#ifdef SQLITE_DEBUG
+  if( pCtx->pVdbe ) pCtx->pVdbe->rcApp = errCode;
+#endif
+  if( pCtx->pOut->flags & MEM_Null ){
+    setResultStrOrError(pCtx, sqlite3ErrStr(errCode), -1, SQLITE_UTF8,
+                        SQLITE_STATIC);
+  }
+}
+
+/* Force an SQLITE_TOOBIG error. */
+SQLITE_API void sqlite3_result_error_toobig(sqlite3_context *pCtx){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  pCtx->isError = SQLITE_TOOBIG;
+  sqlite3VdbeMemSetStr(pCtx->pOut, "string or blob too big", -1,
+                       SQLITE_UTF8, SQLITE_STATIC);
+}
+
+/* An SQLITE_NOMEM error. */
+SQLITE_API void sqlite3_result_error_nomem(sqlite3_context *pCtx){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetNull(pCtx->pOut);
+  pCtx->isError = SQLITE_NOMEM_BKPT;
+  sqlite3OomFault(pCtx->pOut->db);
+}
+
+#ifndef SQLITE_UNTESTABLE
+/* Force the INT64 value currently stored as the result to be
+** a MEM_IntReal value.  See the SQLITE_TESTCTRL_RESULT_INTREAL
+** test-control.
+*/
+SQLITE_PRIVATE void sqlite3ResultIntReal(sqlite3_context *pCtx){
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  if( pCtx->pOut->flags & MEM_Int ){
+    pCtx->pOut->flags &= ~MEM_Int;
+    pCtx->pOut->flags |= MEM_IntReal;
+  }
+}
+#endif
+
+
+/*
+** This function is called after a transaction has been committed. It
+** invokes callbacks registered with sqlite3_wal_hook() as required.
+*/
+static int doWalCallbacks(sqlite3 *db){
+  int rc = SQLITE_OK;
+#ifndef SQLITE_OMIT_WAL
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      int nEntry;
+      sqlite3BtreeEnter(pBt);
+      nEntry = sqlite3PagerWalCallback(sqlite3BtreePager(pBt));
+      sqlite3BtreeLeave(pBt);
+      if( nEntry>0 && db->xWalCallback && rc==SQLITE_OK ){
+        rc = db->xWalCallback(db->pWalArg, db, db->aDb[i].zDbSName, nEntry);
+      }
+    }
+  }
+#endif
+  return rc;
+}
+
+
+/*
+** Execute the statement pStmt, either until a row of data is ready, the
+** statement is completely executed or an error occurs.
+**
+** This routine implements the bulk of the logic behind the sqlite_step()
+** API.  The only thing omitted is the automatic recompile if a
+** schema change has occurred.  That detail is handled by the
+** outer sqlite3_step() wrapper procedure.
+*/
+static int sqlite3Step(Vdbe *p){
+  sqlite3 *db;
+  int rc;
+
+  assert(p);
+  db = p->db;
+  if( p->eVdbeState!=VDBE_RUN_STATE ){
+    restart_step:
+    if( p->eVdbeState==VDBE_READY_STATE ){
+      if( p->expired ){
+        p->rc = SQLITE_SCHEMA;
+        rc = SQLITE_ERROR;
+        if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ){
+          /* If this statement was prepared using saved SQL and an
+          ** error has occurred, then return the error code in p->rc to the
+          ** caller. Set the error code in the database handle to the same
+          ** value.
+          */
+          rc = sqlite3VdbeTransferError(p);
+        }
+        goto end_of_step;
+      }
+
+      /* If there are no other statements currently running, then
+      ** reset the interrupt flag.  This prevents a call to sqlite3_interrupt
+      ** from interrupting a statement that has not yet started.
+      */
+      if( db->nVdbeActive==0 ){
+        AtomicStore(&db->u1.isInterrupted, 0);
+      }
+
+      assert( db->nVdbeWrite>0 || db->autoCommit==0
+          || ((db->nDeferredCons + db->nDeferredImmCons)==0)
+      );
+
+#ifndef SQLITE_OMIT_TRACE
+      if( (db->mTrace & (SQLITE_TRACE_PROFILE|SQLITE_TRACE_XPROFILE))!=0
+          && !db->init.busy && p->zSql ){
+        sqlite3OsCurrentTimeInt64(db->pVfs, &p->startTime);
+      }else{
+        assert( p->startTime==0 );
+      }
+#endif
+
+      db->nVdbeActive++;
+      if( p->readOnly==0 ) db->nVdbeWrite++;
+      if( p->bIsReader ) db->nVdbeRead++;
+      p->pc = 0;
+      p->eVdbeState = VDBE_RUN_STATE;
+    }else
+
+    if( ALWAYS(p->eVdbeState==VDBE_HALT_STATE) ){
+      /* We used to require that sqlite3_reset() be called before retrying
+      ** sqlite3_step() after any error or after SQLITE_DONE.  But beginning
+      ** with version 3.7.0, we changed this so that sqlite3_reset() would
+      ** be called automatically instead of throwing the SQLITE_MISUSE error.
+      ** This "automatic-reset" change is not technically an incompatibility,
+      ** since any application that receives an SQLITE_MISUSE is broken by
+      ** definition.
+      **
+      ** Nevertheless, some published applications that were originally written
+      ** for version 3.6.23 or earlier do in fact depend on SQLITE_MISUSE
+      ** returns, and those were broken by the automatic-reset change.  As a
+      ** a work-around, the SQLITE_OMIT_AUTORESET compile-time restores the
+      ** legacy behavior of returning SQLITE_MISUSE for cases where the
+      ** previous sqlite3_step() returned something other than a SQLITE_LOCKED
+      ** or SQLITE_BUSY error.
+      */
+#ifdef SQLITE_OMIT_AUTORESET
+      if( (rc = p->rc&0xff)==SQLITE_BUSY || rc==SQLITE_LOCKED ){
+        sqlite3_reset((sqlite3_stmt*)p);
+      }else{
+        return SQLITE_MISUSE_BKPT;
+      }
+#else
+      sqlite3_reset((sqlite3_stmt*)p);
+#endif
+      assert( p->eVdbeState==VDBE_READY_STATE );
+      goto restart_step;
+    }
+  }
+
+#ifdef SQLITE_DEBUG
+  p->rcApp = SQLITE_OK;
+#endif
+#ifndef SQLITE_OMIT_EXPLAIN
+  if( p->explain ){
+    rc = sqlite3VdbeList(p);
+  }else
+#endif /* SQLITE_OMIT_EXPLAIN */
+  {
+    db->nVdbeExec++;
+    rc = sqlite3VdbeExec(p);
+    db->nVdbeExec--;
+  }
+
+  if( rc==SQLITE_ROW ){
+    assert( p->rc==SQLITE_OK );
+    assert( db->mallocFailed==0 );
+    db->errCode = SQLITE_ROW;
+    return SQLITE_ROW;
+  }else{
+#ifndef SQLITE_OMIT_TRACE
+    /* If the statement completed successfully, invoke the profile callback */
+    checkProfileCallback(db, p);
+#endif
+    p->pResultRow = 0;
+    if( rc==SQLITE_DONE && db->autoCommit ){
+      assert( p->rc==SQLITE_OK );
+      p->rc = doWalCallbacks(db);
+      if( p->rc!=SQLITE_OK ){
+        rc = SQLITE_ERROR;
+      }
+    }else if( rc!=SQLITE_DONE && (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ){
+      /* If this statement was prepared using saved SQL and an
+      ** error has occurred, then return the error code in p->rc to the
+      ** caller. Set the error code in the database handle to the same value.
+      */
+      rc = sqlite3VdbeTransferError(p);
+    }
+  }
+
+  db->errCode = rc;
+  if( SQLITE_NOMEM==sqlite3ApiExit(p->db, p->rc) ){
+    p->rc = SQLITE_NOMEM_BKPT;
+    if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ) rc = p->rc;
+  }
+end_of_step:
+  /* There are only a limited number of result codes allowed from the
+  ** statements prepared using the legacy sqlite3_prepare() interface */
+  assert( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0
+       || rc==SQLITE_ROW  || rc==SQLITE_DONE   || rc==SQLITE_ERROR
+       || (rc&0xff)==SQLITE_BUSY || rc==SQLITE_MISUSE
+  );
+  return (rc&db->errMask);
+}
+
+/*
+** This is the top-level implementation of sqlite3_step().  Call
+** sqlite3Step() to do most of the work.  If a schema error occurs,
+** call sqlite3Reprepare() and try again.
+*/
+SQLITE_API int sqlite3_step(sqlite3_stmt *pStmt){
+  int rc = SQLITE_OK;      /* Result from sqlite3Step() */
+  Vdbe *v = (Vdbe*)pStmt;  /* the prepared statement */
+  int cnt = 0;             /* Counter to prevent infinite loop of reprepares */
+  sqlite3 *db;             /* The database connection */
+
+  if( vdbeSafetyNotNull(v) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  db = v->db;
+  sqlite3_mutex_enter(db->mutex);
+  while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
+         && cnt++ < SQLITE_MAX_SCHEMA_RETRY ){
+    int savedPc = v->pc;
+    rc = sqlite3Reprepare(v);
+    if( rc!=SQLITE_OK ){
+      /* This case occurs after failing to recompile an sql statement.
+      ** The error message from the SQL compiler has already been loaded
+      ** into the database handle. This block copies the error message
+      ** from the database handle into the statement and sets the statement
+      ** program counter to 0 to ensure that when the statement is
+      ** finalized or reset the parser error message is available via
+      ** sqlite3_errmsg() and sqlite3_errcode().
+      */
+      const char *zErr = (const char *)sqlite3_value_text(db->pErr);
+      sqlite3DbFree(db, v->zErrMsg);
+      if( !db->mallocFailed ){
+        v->zErrMsg = sqlite3DbStrDup(db, zErr);
+        v->rc = rc = sqlite3ApiExit(db, rc);
+      } else {
+        v->zErrMsg = 0;
+        v->rc = rc = SQLITE_NOMEM_BKPT;
+      }
+      break;
+    }
+    sqlite3_reset(pStmt);
+    if( savedPc>=0 ){
+      /* Setting minWriteFileFormat to 254 is a signal to the OP_Init and
+      ** OP_Trace opcodes to *not* perform SQLITE_TRACE_STMT because it has
+      ** already been done once on a prior invocation that failed due to
+      ** SQLITE_SCHEMA.   tag-20220401a  */
+      v->minWriteFileFormat = 254;
+    }
+    assert( v->expired==0 );
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+
+/*
+** Extract the user data from a sqlite3_context structure and return a
+** pointer to it.
+*/
+SQLITE_API void *sqlite3_user_data(sqlite3_context *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return 0;
+#endif
+  assert( p && p->pFunc );
+  return p->pFunc->pUserData;
+}
+
+/*
+** Extract the user data from a sqlite3_context structure and return a
+** pointer to it.
+**
+** IMPLEMENTATION-OF: R-46798-50301 The sqlite3_context_db_handle() interface
+** returns a copy of the pointer to the database connection (the 1st
+** parameter) of the sqlite3_create_function() and
+** sqlite3_create_function16() routines that originally registered the
+** application defined function.
+*/
+SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return 0;
+#else
+  assert( p && p->pOut );
+#endif
+  return p->pOut->db;
+}
+
+/*
+** If this routine is invoked from within an xColumn method of a virtual
+** table, then it returns true if and only if the the call is during an
+** UPDATE operation and the value of the column will not be modified
+** by the UPDATE.
+**
+** If this routine is called from any context other than within the
+** xColumn method of a virtual table, then the return value is meaningless
+** and arbitrary.
+**
+** Virtual table implements might use this routine to optimize their
+** performance by substituting a NULL result, or some other light-weight
+** value, as a signal to the xUpdate routine that the column is unchanged.
+*/
+SQLITE_API int sqlite3_vtab_nochange(sqlite3_context *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return 0;
+#else
+  assert( p );
+#endif
+  return sqlite3_value_nochange(p->pOut);
+}
+
+/*
+** The destructor function for a ValueList object.  This needs to be
+** a separate function, unknowable to the application, to ensure that
+** calls to sqlite3_vtab_in_first()/sqlite3_vtab_in_next() that are not
+** preceded by activation of IN processing via sqlite3_vtab_int() do not
+** try to access a fake ValueList object inserted by a hostile extension.
+*/
+SQLITE_PRIVATE void sqlite3VdbeValueListFree(void *pToDelete){
+  sqlite3_free(pToDelete);
+}
+
+/*
+** Implementation of sqlite3_vtab_in_first() (if bNext==0) and
+** sqlite3_vtab_in_next() (if bNext!=0).
+*/
+static int valueFromValueList(
+  sqlite3_value *pVal,        /* Pointer to the ValueList object */
+  sqlite3_value **ppOut,      /* Store the next value from the list here */
+  int bNext                   /* 1 for _next(). 0 for _first() */
+){
+  int rc;
+  ValueList *pRhs;
+
+  *ppOut = 0;
+  if( pVal==0 ) return SQLITE_MISUSE_BKPT;
+  if( (pVal->flags & MEM_Dyn)==0 || pVal->xDel!=sqlite3VdbeValueListFree ){
+    return SQLITE_ERROR;
+  }else{
+    assert( (pVal->flags&(MEM_TypeMask|MEM_Term|MEM_Subtype)) ==
+                 (MEM_Null|MEM_Term|MEM_Subtype) );
+    assert( pVal->eSubtype=='p' );
+    assert( pVal->u.zPType!=0 && strcmp(pVal->u.zPType,"ValueList")==0 );
+    pRhs = (ValueList*)pVal->z;
+  }
+  if( bNext ){
+    rc = sqlite3BtreeNext(pRhs->pCsr, 0);
+  }else{
+    int dummy = 0;
+    rc = sqlite3BtreeFirst(pRhs->pCsr, &dummy);
+    assert( rc==SQLITE_OK || sqlite3BtreeEof(pRhs->pCsr) );
+    if( sqlite3BtreeEof(pRhs->pCsr) ) rc = SQLITE_DONE;
+  }
+  if( rc==SQLITE_OK ){
+    u32 sz;       /* Size of current row in bytes */
+    Mem sMem;     /* Raw content of current row */
+    memset(&sMem, 0, sizeof(sMem));
+    sz = sqlite3BtreePayloadSize(pRhs->pCsr);
+    rc = sqlite3VdbeMemFromBtreeZeroOffset(pRhs->pCsr,(int)sz,&sMem);
+    if( rc==SQLITE_OK ){
+      u8 *zBuf = (u8*)sMem.z;
+      u32 iSerial;
+      sqlite3_value *pOut = pRhs->pOut;
+      int iOff = 1 + getVarint32(&zBuf[1], iSerial);
+      sqlite3VdbeSerialGet(&zBuf[iOff], iSerial, pOut);
+      pOut->enc = ENC(pOut->db);
+      if( (pOut->flags & MEM_Ephem)!=0 && sqlite3VdbeMemMakeWriteable(pOut) ){
+        rc = SQLITE_NOMEM;
+      }else{
+        *ppOut = pOut;
+      }
+    }
+    sqlite3VdbeMemRelease(&sMem);
+  }
+  return rc;
+}
+
+/*
+** Set the iterator value pVal to point to the first value in the set.
+** Set (*ppOut) to point to this value before returning.
+*/
+SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut){
+  return valueFromValueList(pVal, ppOut, 0);
+}
+
+/*
+** Set the iterator value pVal to point to the next value in the set.
+** Set (*ppOut) to point to this value before returning.
+*/
+SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut){
+  return valueFromValueList(pVal, ppOut, 1);
+}
+
+/*
+** Return the current time for a statement.  If the current time
+** is requested more than once within the same run of a single prepared
+** statement, the exact same time is returned for each invocation regardless
+** of the amount of time that elapses between invocations.  In other words,
+** the time returned is always the time of the first call.
+*/
+SQLITE_PRIVATE sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context *p){
+  int rc;
+#ifndef SQLITE_ENABLE_STAT4
+  sqlite3_int64 *piTime = &p->pVdbe->iCurrentTime;
+  assert( p->pVdbe!=0 );
+#else
+  sqlite3_int64 iTime = 0;
+  sqlite3_int64 *piTime = p->pVdbe!=0 ? &p->pVdbe->iCurrentTime : &iTime;
+#endif
+  if( *piTime==0 ){
+    rc = sqlite3OsCurrentTimeInt64(p->pOut->db->pVfs, piTime);
+    if( rc ) *piTime = 0;
+  }
+  return *piTime;
+}
+
+/*
+** Create a new aggregate context for p and return a pointer to
+** its pMem->z element.
+*/
+static SQLITE_NOINLINE void *createAggContext(sqlite3_context *p, int nByte){
+  Mem *pMem = p->pMem;
+  assert( (pMem->flags & MEM_Agg)==0 );
+  if( nByte<=0 ){
+    sqlite3VdbeMemSetNull(pMem);
+    pMem->z = 0;
+  }else{
+    sqlite3VdbeMemClearAndResize(pMem, nByte);
+    pMem->flags = MEM_Agg;
+    pMem->u.pDef = p->pFunc;
+    if( pMem->z ){
+      memset(pMem->z, 0, nByte);
+    }
+  }
+  return (void*)pMem->z;
+}
+
+/*
+** Allocate or return the aggregate context for a user function.  A new
+** context is allocated on the first call.  Subsequent calls return the
+** same context that was returned on prior calls.
+*/
+SQLITE_API void *sqlite3_aggregate_context(sqlite3_context *p, int nByte){
+  assert( p && p->pFunc && p->pFunc->xFinalize );
+  assert( sqlite3_mutex_held(p->pOut->db->mutex) );
+  testcase( nByte<0 );
+  if( (p->pMem->flags & MEM_Agg)==0 ){
+    return createAggContext(p, nByte);
+  }else{
+    return (void*)p->pMem->z;
+  }
+}
+
+/*
+** Return the auxiliary data pointer, if any, for the iArg'th argument to
+** the user-function defined by pCtx.
+**
+** The left-most argument is 0.
+**
+** Undocumented behavior:  If iArg is negative then access a cache of
+** auxiliary data pointers that is available to all functions within a
+** single prepared statement.  The iArg values must match.
+*/
+SQLITE_API void *sqlite3_get_auxdata(sqlite3_context *pCtx, int iArg){
+  AuxData *pAuxData;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return 0;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+#if SQLITE_ENABLE_STAT4
+  if( pCtx->pVdbe==0 ) return 0;
+#else
+  assert( pCtx->pVdbe!=0 );
+#endif
+  for(pAuxData=pCtx->pVdbe->pAuxData; pAuxData; pAuxData=pAuxData->pNextAux){
+    if(  pAuxData->iAuxArg==iArg && (pAuxData->iAuxOp==pCtx->iOp || iArg<0) ){
+      return pAuxData->pAux;
+    }
+  }
+  return 0;
+}
+
+/*
+** Set the auxiliary data pointer and delete function, for the iArg'th
+** argument to the user-function defined by pCtx. Any previous value is
+** deleted by calling the delete function specified when it was set.
+**
+** The left-most argument is 0.
+**
+** Undocumented behavior:  If iArg is negative then make the data available
+** to all functions within the current prepared statement using iArg as an
+** access code.
+*/
+SQLITE_API void sqlite3_set_auxdata(
+  sqlite3_context *pCtx,
+  int iArg,
+  void *pAux,
+  void (*xDelete)(void*)
+){
+  AuxData *pAuxData;
+  Vdbe *pVdbe;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  pVdbe= pCtx->pVdbe;
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+#ifdef SQLITE_ENABLE_STAT4
+  if( pVdbe==0 ) goto failed;
+#else
+  assert( pVdbe!=0 );
+#endif
+
+  for(pAuxData=pVdbe->pAuxData; pAuxData; pAuxData=pAuxData->pNextAux){
+    if( pAuxData->iAuxArg==iArg && (pAuxData->iAuxOp==pCtx->iOp || iArg<0) ){
+      break;
+    }
+  }
+  if( pAuxData==0 ){
+    pAuxData = sqlite3DbMallocZero(pVdbe->db, sizeof(AuxData));
+    if( !pAuxData ) goto failed;
+    pAuxData->iAuxOp = pCtx->iOp;
+    pAuxData->iAuxArg = iArg;
+    pAuxData->pNextAux = pVdbe->pAuxData;
+    pVdbe->pAuxData = pAuxData;
+    if( pCtx->isError==0 ) pCtx->isError = -1;
+  }else if( pAuxData->xDeleteAux ){
+    pAuxData->xDeleteAux(pAuxData->pAux);
+  }
+
+  pAuxData->pAux = pAux;
+  pAuxData->xDeleteAux = xDelete;
+  return;
+
+failed:
+  if( xDelete ){
+    xDelete(pAux);
+  }
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Return the number of times the Step function of an aggregate has been
+** called.
+**
+** This function is deprecated.  Do not use it for new code.  It is
+** provide only to avoid breaking legacy code.  New aggregate function
+** implementations should keep their own counts within their aggregate
+** context.
+*/
+SQLITE_API int sqlite3_aggregate_count(sqlite3_context *p){
+  assert( p && p->pMem && p->pFunc && p->pFunc->xFinalize );
+  return p->pMem->n;
+}
+#endif
+
+/*
+** Return the number of columns in the result set for the statement pStmt.
+*/
+SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt){
+  Vdbe *pVm = (Vdbe *)pStmt;
+  if( pVm==0 ) return 0;
+  return pVm->nResColumn;
+}
+
+/*
+** Return the number of values available from the current row of the
+** currently executing statement pStmt.
+*/
+SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt){
+  Vdbe *pVm = (Vdbe *)pStmt;
+  if( pVm==0 || pVm->pResultRow==0 ) return 0;
+  return pVm->nResColumn;
+}
+
+/*
+** Return a pointer to static memory containing an SQL NULL value.
+*/
+static const Mem *columnNullValue(void){
+  /* Even though the Mem structure contains an element
+  ** of type i64, on certain architectures (x86) with certain compiler
+  ** switches (-Os), gcc may align this Mem object on a 4-byte boundary
+  ** instead of an 8-byte one. This all works fine, except that when
+  ** running with SQLITE_DEBUG defined the SQLite code sometimes assert()s
+  ** that a Mem structure is located on an 8-byte boundary. To prevent
+  ** these assert()s from failing, when building with SQLITE_DEBUG defined
+  ** using gcc, we force nullMem to be 8-byte aligned using the magical
+  ** __attribute__((aligned(8))) macro.  */
+  static const Mem nullMem
+#if defined(SQLITE_DEBUG) && defined(__GNUC__)
+    __attribute__((aligned(8)))
+#endif
+    = {
+        /* .u          = */ {0},
+        /* .z          = */ (char*)0,
+        /* .n          = */ (int)0,
+        /* .flags      = */ (u16)MEM_Null,
+        /* .enc        = */ (u8)0,
+        /* .eSubtype   = */ (u8)0,
+        /* .db         = */ (sqlite3*)0,
+        /* .szMalloc   = */ (int)0,
+        /* .uTemp      = */ (u32)0,
+        /* .zMalloc    = */ (char*)0,
+        /* .xDel       = */ (void(*)(void*))0,
+#ifdef SQLITE_DEBUG
+        /* .pScopyFrom = */ (Mem*)0,
+        /* .mScopyFlags= */ 0,
+        /* .bScopy     = */ 0,
+#endif
+      };
+  return &nullMem;
+}
+
+/*
+** Check to see if column iCol of the given statement is valid.  If
+** it is, return a pointer to the Mem for the value of that column.
+** If iCol is not valid, return a pointer to a Mem which has a value
+** of NULL.
+*/
+static Mem *columnMem(sqlite3_stmt *pStmt, int i){
+  Vdbe *pVm;
+  Mem *pOut;
+
+  pVm = (Vdbe *)pStmt;
+  if( pVm==0 ) return (Mem*)columnNullValue();
+  assert( pVm->db );
+  sqlite3_mutex_enter(pVm->db->mutex);
+  if( pVm->pResultRow!=0 && i<pVm->nResColumn && i>=0 ){
+    pOut = &pVm->pResultRow[i];
+  }else{
+    sqlite3Error(pVm->db, SQLITE_RANGE);
+    pOut = (Mem*)columnNullValue();
+  }
+  return pOut;
+}
+
+/*
+** This function is called after invoking an sqlite3_value_XXX function on a
+** column value (i.e. a value returned by evaluating an SQL expression in the
+** select list of a SELECT statement) that may cause a malloc() failure. If
+** malloc() has failed, the threads mallocFailed flag is cleared and the result
+** code of statement pStmt set to SQLITE_NOMEM.
+**
+** Specifically, this is called from within:
+**
+**     sqlite3_column_int()
+**     sqlite3_column_int64()
+**     sqlite3_column_text()
+**     sqlite3_column_text16()
+**     sqlite3_column_double()
+**     sqlite3_column_bytes()
+**     sqlite3_column_bytes16()
+**     sqlite3_column_blob()
+*/
+static void columnMallocFailure(sqlite3_stmt *pStmt)
+{
+  /* If malloc() failed during an encoding conversion within an
+  ** sqlite3_column_XXX API, then set the return code of the statement to
+  ** SQLITE_NOMEM. The next call to _step() (if any) will return SQLITE_ERROR
+  ** and _finalize() will return NOMEM.
+  */
+  Vdbe *p = (Vdbe *)pStmt;
+  if( p ){
+    assert( p->db!=0 );
+    assert( sqlite3_mutex_held(p->db->mutex) );
+    p->rc = sqlite3ApiExit(p->db, p->rc);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+}
+
+/**************************** sqlite3_column_  *******************************
+** The following routines are used to access elements of the current row
+** in the result set.
+*/
+SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt *pStmt, int i){
+  const void *val;
+  val = sqlite3_value_blob( columnMem(pStmt,i) );
+  /* Even though there is no encoding conversion, value_blob() might
+  ** need to call malloc() to expand the result of a zeroblob()
+  ** expression.
+  */
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API int sqlite3_column_bytes(sqlite3_stmt *pStmt, int i){
+  int val = sqlite3_value_bytes( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt *pStmt, int i){
+  int val = sqlite3_value_bytes16( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API double sqlite3_column_double(sqlite3_stmt *pStmt, int i){
+  double val = sqlite3_value_double( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API int sqlite3_column_int(sqlite3_stmt *pStmt, int i){
+  int val = sqlite3_value_int( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API sqlite_int64 sqlite3_column_int64(sqlite3_stmt *pStmt, int i){
+  sqlite_int64 val = sqlite3_value_int64( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt *pStmt, int i){
+  const unsigned char *val = sqlite3_value_text( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt *pStmt, int i){
+  Mem *pOut = columnMem(pStmt, i);
+  if( pOut->flags&MEM_Static ){
+    pOut->flags &= ~MEM_Static;
+    pOut->flags |= MEM_Ephem;
+  }
+  columnMallocFailure(pStmt);
+  return (sqlite3_value *)pOut;
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt *pStmt, int i){
+  const void *val = sqlite3_value_text16( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API int sqlite3_column_type(sqlite3_stmt *pStmt, int i){
+  int iType = sqlite3_value_type( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return iType;
+}
+
+/*
+** Column names appropriate for EXPLAIN or EXPLAIN QUERY PLAN.
+*/
+static const char * const azExplainColNames8[] = {
+   "addr", "opcode", "p1", "p2", "p3", "p4", "p5", "comment",  /* EXPLAIN */
+   "id", "parent", "notused", "detail"                         /* EQP */
+};
+static const u16 azExplainColNames16data[] = {
+  /*   0 */  'a', 'd', 'd', 'r',                0,
+  /*   5 */  'o', 'p', 'c', 'o', 'd', 'e',      0,
+  /*  12 */  'p', '1',                          0,
+  /*  15 */  'p', '2',                          0,
+  /*  18 */  'p', '3',                          0,
+  /*  21 */  'p', '4',                          0,
+  /*  24 */  'p', '5',                          0,
+  /*  27 */  'c', 'o', 'm', 'm', 'e', 'n', 't', 0,
+  /*  35 */  'i', 'd',                          0,
+  /*  38 */  'p', 'a', 'r', 'e', 'n', 't',      0,
+  /*  45 */  'n', 'o', 't', 'u', 's', 'e', 'd', 0,
+  /*  53 */  'd', 'e', 't', 'a', 'i', 'l',      0
+};
+static const u8 iExplainColNames16[] = {
+  0, 5, 12, 15, 18, 21, 24, 27,
+  35, 38, 45, 53
+};
+
+/*
+** Convert the N-th element of pStmt->pColName[] into a string using
+** xFunc() then return that string.  If N is out of range, return 0.
+**
+** There are up to 5 names for each column.  useType determines which
+** name is returned.  Here are the names:
+**
+**    0      The column name as it should be displayed for output
+**    1      The datatype name for the column
+**    2      The name of the database that the column derives from
+**    3      The name of the table that the column derives from
+**    4      The name of the table column that the result column derives from
+**
+** If the result is not a simple column reference (if it is an expression
+** or a constant) then useTypes 2, 3, and 4 return NULL.
+*/
+static const void *columnName(
+  sqlite3_stmt *pStmt,     /* The statement */
+  int N,                   /* Which column to get the name for */
+  int useUtf16,            /* True to return the name as UTF16 */
+  int useType              /* What type of name */
+){
+  const void *ret;
+  Vdbe *p;
+  int n;
+  sqlite3 *db;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pStmt==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  if( N<0 ) return 0;
+  ret = 0;
+  p = (Vdbe *)pStmt;
+  db = p->db;
+  assert( db!=0 );
+  sqlite3_mutex_enter(db->mutex);
+
+  if( p->explain ){
+    if( useType>0 ) goto columnName_end;
+    n = p->explain==1 ? 8 : 4;
+    if( N>=n ) goto columnName_end;
+    if( useUtf16 ){
+      int i = iExplainColNames16[N + 8*p->explain - 8];
+      ret = (void*)&azExplainColNames16data[i];
+    }else{
+      ret = (void*)azExplainColNames8[N + 8*p->explain - 8];
+    }
+    goto columnName_end;
+  }
+  n = p->nResColumn;
+  if( N<n ){
+    u8 prior_mallocFailed = db->mallocFailed;
+    N += useType*n;
+#ifndef SQLITE_OMIT_UTF16
+    if( useUtf16 ){
+      ret = sqlite3_value_text16((sqlite3_value*)&p->aColName[N]);
+    }else
+#endif
+    {
+      ret = sqlite3_value_text((sqlite3_value*)&p->aColName[N]);
+    }
+    /* A malloc may have failed inside of the _text() call. If this
+    ** is the case, clear the mallocFailed flag and return NULL.
+    */
+    assert( db->mallocFailed==0 || db->mallocFailed==1 );
+    if( db->mallocFailed > prior_mallocFailed ){
+      sqlite3OomClear(db);
+      ret = 0;
+    }
+  }
+columnName_end:
+  sqlite3_mutex_leave(db->mutex);
+  return ret;
+}
+
+/*
+** Return the name of the Nth column of the result set returned by SQL
+** statement pStmt.
+*/
+SQLITE_API const char *sqlite3_column_name(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_NAME);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_NAME);
+}
+#endif
+
+/*
+** Constraint:  If you have ENABLE_COLUMN_METADATA then you must
+** not define OMIT_DECLTYPE.
+*/
+#if defined(SQLITE_OMIT_DECLTYPE) && defined(SQLITE_ENABLE_COLUMN_METADATA)
+# error "Must not define both SQLITE_OMIT_DECLTYPE \
+         and SQLITE_ENABLE_COLUMN_METADATA"
+#endif
+
+#ifndef SQLITE_OMIT_DECLTYPE
+/*
+** Return the column declaration type (if applicable) of the 'i'th column
+** of the result set of SQL statement pStmt.
+*/
+SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_DECLTYPE);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_DECLTYPE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+#endif /* SQLITE_OMIT_DECLTYPE */
+
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+/*
+** Return the name of the database from which a result column derives.
+** NULL is returned if the result column is an expression or constant or
+** anything else which is not an unambiguous reference to a database column.
+*/
+SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_DATABASE);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_DATABASE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Return the name of the table from which a result column derives.
+** NULL is returned if the result column is an expression or constant or
+** anything else which is not an unambiguous reference to a database column.
+*/
+SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_TABLE);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_TABLE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Return the name of the table column from which a result column derives.
+** NULL is returned if the result column is an expression or constant or
+** anything else which is not an unambiguous reference to a database column.
+*/
+SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_COLUMN);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_COLUMN);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+#endif /* SQLITE_ENABLE_COLUMN_METADATA */
+
+
+/******************************* sqlite3_bind_  ***************************
+**
+** Routines used to attach values to wildcards in a compiled SQL statement.
+*/
+/*
+** Unbind the value bound to variable i in virtual machine p. This is the
+** the same as binding a NULL value to the column. If the "i" parameter is
+** out of range, then SQLITE_RANGE is returned. Otherwise SQLITE_OK.
+**
+** A successful evaluation of this routine acquires the mutex on p.
+** the mutex is released if any kind of error occurs.
+**
+** The error code stored in database p->db is overwritten with the return
+** value in any case.
+**
+** (tag-20240917-01) If  vdbeUnbind(p,(u32)(i-1))  returns SQLITE_OK,
+** that means all of the the following will be true:
+**
+**     p!=0
+**     p->pVar!=0
+**     i>0
+**     i<=p->nVar
+**
+** An assert() is normally added after vdbeUnbind() to help static analyzers
+** realize this.
+*/
+static int vdbeUnbind(Vdbe *p, unsigned int i){
+  Mem *pVar;
+  if( vdbeSafetyNotNull(p) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  sqlite3_mutex_enter(p->db->mutex);
+  if( p->eVdbeState!=VDBE_READY_STATE ){
+    sqlite3Error(p->db, SQLITE_MISUSE_BKPT);
+    sqlite3_mutex_leave(p->db->mutex);
+    sqlite3_log(SQLITE_MISUSE,
+        "bind on a busy prepared statement: [%s]", p->zSql);
+    return SQLITE_MISUSE_BKPT;
+  }
+  if( i>=(unsigned int)p->nVar ){
+    sqlite3Error(p->db, SQLITE_RANGE);
+    sqlite3_mutex_leave(p->db->mutex);
+    return SQLITE_RANGE;
+  }
+  pVar = &p->aVar[i];
+  sqlite3VdbeMemRelease(pVar);
+  pVar->flags = MEM_Null;
+  p->db->errCode = SQLITE_OK;
+
+  /* If the bit corresponding to this variable in Vdbe.expmask is set, then
+  ** binding a new value to this variable invalidates the current query plan.
+  **
+  ** IMPLEMENTATION-OF: R-57496-20354 If the specific value bound to a host
+  ** parameter in the WHERE clause might influence the choice of query plan
+  ** for a statement, then the statement will be automatically recompiled,
+  ** as if there had been a schema change, on the first sqlite3_step() call
+  ** following any change to the bindings of that parameter.
+  */
+  assert( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || p->expmask==0 );
+  if( p->expmask!=0 && (p->expmask & (i>=31 ? 0x80000000 : (u32)1<<i))!=0 ){
+    p->expired = 1;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Bind a text or BLOB value.
+*/
+static int bindText(
+  sqlite3_stmt *pStmt,   /* The statement to bind against */
+  int i,                 /* Index of the parameter to bind */
+  const void *zData,     /* Pointer to the data to be bound */
+  i64 nData,             /* Number of bytes of data to be bound */
+  void (*xDel)(void*),   /* Destructor for the data */
+  u8 encoding            /* Encoding for the data */
+){
+  Vdbe *p = (Vdbe *)pStmt;
+  Mem *pVar;
+  int rc;
+
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    if( zData!=0 ){
+      pVar = &p->aVar[i-1];
+      rc = sqlite3VdbeMemSetStr(pVar, zData, nData, encoding, xDel);
+      if( rc==SQLITE_OK && encoding!=0 ){
+        rc = sqlite3VdbeChangeEncoding(pVar, ENC(p->db));
+      }
+      if( rc ){
+        sqlite3Error(p->db, rc);
+        rc = sqlite3ApiExit(p->db, rc);
+      }
+    }
+    sqlite3_mutex_leave(p->db->mutex);
+  }else if( xDel!=SQLITE_STATIC && xDel!=SQLITE_TRANSIENT ){
+    xDel((void*)zData);
+  }
+  return rc;
+}
+
+
+/*
+** Bind a blob value to an SQL statement variable.
+*/
+SQLITE_API int sqlite3_bind_blob(
+  sqlite3_stmt *pStmt,
+  int i,
+  const void *zData,
+  int nData,
+  void (*xDel)(void*)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( nData<0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  return bindText(pStmt, i, zData, nData, xDel, 0);
+}
+SQLITE_API int sqlite3_bind_blob64(
+  sqlite3_stmt *pStmt,
+  int i,
+  const void *zData,
+  sqlite3_uint64 nData,
+  void (*xDel)(void*)
+){
+  assert( xDel!=SQLITE_DYNAMIC );
+  return bindText(pStmt, i, zData, nData, xDel, 0);
+}
+SQLITE_API int sqlite3_bind_double(sqlite3_stmt *pStmt, int i, double rValue){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    sqlite3VdbeMemSetDouble(&p->aVar[i-1], rValue);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_int(sqlite3_stmt *p, int i, int iValue){
+  return sqlite3_bind_int64(p, i, (i64)iValue);
+}
+SQLITE_API int sqlite3_bind_int64(sqlite3_stmt *pStmt, int i, sqlite_int64 iValue){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    sqlite3VdbeMemSetInt64(&p->aVar[i-1], iValue);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_null(sqlite3_stmt *pStmt, int i){
+  int rc;
+  Vdbe *p = (Vdbe*)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_pointer(
+  sqlite3_stmt *pStmt,
+  int i,
+  void *pPtr,
+  const char *zPTtype,
+  void (*xDestructor)(void*)
+){
+  int rc;
+  Vdbe *p = (Vdbe*)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    sqlite3VdbeMemSetPointer(&p->aVar[i-1], pPtr, zPTtype, xDestructor);
+    sqlite3_mutex_leave(p->db->mutex);
+  }else if( xDestructor ){
+    xDestructor(pPtr);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_text(
+  sqlite3_stmt *pStmt,
+  int i,
+  const char *zData,
+  int nData,
+  void (*xDel)(void*)
+){
+  return bindText(pStmt, i, zData, nData, xDel, SQLITE_UTF8);
+}
+SQLITE_API int sqlite3_bind_text64(
+  sqlite3_stmt *pStmt,
+  int i,
+  const char *zData,
+  sqlite3_uint64 nData,
+  void (*xDel)(void*),
+  unsigned char enc
+){
+  assert( xDel!=SQLITE_DYNAMIC );
+  if( enc!=SQLITE_UTF8 ){
+    if( enc==SQLITE_UTF16 ) enc = SQLITE_UTF16NATIVE;
+    nData &= ~(u16)1;
+  }
+  return bindText(pStmt, i, zData, nData, xDel, enc);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API int sqlite3_bind_text16(
+  sqlite3_stmt *pStmt,
+  int i,
+  const void *zData,
+  int n,
+  void (*xDel)(void*)
+){
+  return bindText(pStmt, i, zData, n & ~(u64)1, xDel, SQLITE_UTF16NATIVE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API int sqlite3_bind_value(sqlite3_stmt *pStmt, int i, const sqlite3_value *pValue){
+  int rc;
+  switch( sqlite3_value_type((sqlite3_value*)pValue) ){
+    case SQLITE_INTEGER: {
+      rc = sqlite3_bind_int64(pStmt, i, pValue->u.i);
+      break;
+    }
+    case SQLITE_FLOAT: {
+      assert( pValue->flags & (MEM_Real|MEM_IntReal) );
+      rc = sqlite3_bind_double(pStmt, i,
+          (pValue->flags & MEM_Real) ? pValue->u.r : (double)pValue->u.i
+      );
+      break;
+    }
+    case SQLITE_BLOB: {
+      if( pValue->flags & MEM_Zero ){
+        rc = sqlite3_bind_zeroblob(pStmt, i, pValue->u.nZero);
+      }else{
+        rc = sqlite3_bind_blob(pStmt, i, pValue->z, pValue->n,SQLITE_TRANSIENT);
+      }
+      break;
+    }
+    case SQLITE_TEXT: {
+      rc = bindText(pStmt,i,  pValue->z, pValue->n, SQLITE_TRANSIENT,
+                              pValue->enc);
+      break;
+    }
+    default: {
+      rc = sqlite3_bind_null(pStmt, i);
+      break;
+    }
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt *pStmt, int i, int n){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+#ifndef SQLITE_OMIT_INCRBLOB
+    sqlite3VdbeMemSetZeroBlob(&p->aVar[i-1], n);
+#else
+    rc = sqlite3VdbeMemSetZeroBlob(&p->aVar[i-1], n);
+#endif
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt *pStmt, int i, sqlite3_uint64 n){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(p->db->mutex);
+  if( n>(u64)p->db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    rc = SQLITE_TOOBIG;
+  }else{
+    assert( (n & 0x7FFFFFFF)==n );
+    rc = sqlite3_bind_zeroblob(pStmt, i, n);
+  }
+  rc = sqlite3ApiExit(p->db, rc);
+  sqlite3_mutex_leave(p->db->mutex);
+  return rc;
+}
+
+/*
+** Return the number of wildcards that can be potentially bound to.
+** This routine is added to support DBD::SQLite.
+*/
+SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe*)pStmt;
+  return p ? p->nVar : 0;
+}
+
+/*
+** Return the name of a wildcard parameter.  Return NULL if the index
+** is out of range or if the wildcard is unnamed.
+**
+** The result is always UTF-8.
+*/
+SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt *pStmt, int i){
+  Vdbe *p = (Vdbe*)pStmt;
+  if( p==0 ) return 0;
+  return sqlite3VListNumToName(p->pVList, i);
+}
+
+/*
+** Given a wildcard parameter name, return the index of the variable
+** with that name.  If there is no variable with the given name,
+** return 0.
+*/
+SQLITE_PRIVATE int sqlite3VdbeParameterIndex(Vdbe *p, const char *zName, int nName){
+  if( p==0 || zName==0 ) return 0;
+  return sqlite3VListNameToNum(p->pVList, zName, nName);
+}
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt *pStmt, const char *zName){
+  return sqlite3VdbeParameterIndex((Vdbe*)pStmt, zName, sqlite3Strlen30(zName));
+}
+
+/*
+** Transfer all bindings from the first statement over to the second.
+*/
+SQLITE_PRIVATE int sqlite3TransferBindings(sqlite3_stmt *pFromStmt, sqlite3_stmt *pToStmt){
+  Vdbe *pFrom = (Vdbe*)pFromStmt;
+  Vdbe *pTo = (Vdbe*)pToStmt;
+  int i;
+  assert( pTo->db==pFrom->db );
+  assert( pTo->nVar==pFrom->nVar );
+  sqlite3_mutex_enter(pTo->db->mutex);
+  for(i=0; i<pFrom->nVar; i++){
+    sqlite3VdbeMemMove(&pTo->aVar[i], &pFrom->aVar[i]);
+  }
+  sqlite3_mutex_leave(pTo->db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Deprecated external interface.  Internal/core SQLite code
+** should call sqlite3TransferBindings.
+**
+** It is misuse to call this routine with statements from different
+** database connections.  But as this is a deprecated interface, we
+** will not bother to check for that condition.
+**
+** If the two statements contain a different number of bindings, then
+** an SQLITE_ERROR is returned.  Nothing else can go wrong, so otherwise
+** SQLITE_OK is returned.
+*/
+SQLITE_API int sqlite3_transfer_bindings(sqlite3_stmt *pFromStmt, sqlite3_stmt *pToStmt){
+  Vdbe *pFrom = (Vdbe*)pFromStmt;
+  Vdbe *pTo = (Vdbe*)pToStmt;
+  if( pFrom->nVar!=pTo->nVar ){
+    return SQLITE_ERROR;
+  }
+  assert( (pTo->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || pTo->expmask==0 );
+  if( pTo->expmask ){
+    pTo->expired = 1;
+  }
+  assert( (pFrom->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || pFrom->expmask==0 );
+  if( pFrom->expmask ){
+    pFrom->expired = 1;
+  }
+  return sqlite3TransferBindings(pFromStmt, pToStmt);
+}
+#endif
+
+/*
+** Return the sqlite3* database handle to which the prepared statement given
+** in the argument belongs.  This is the same database handle that was
+** the first argument to the sqlite3_prepare() that was used to create
+** the statement in the first place.
+*/
+SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt *pStmt){
+  return pStmt ? ((Vdbe*)pStmt)->db : 0;
+}
+
+/*
+** Return true if the prepared statement is guaranteed to not modify the
+** database.
+*/
+SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt){
+  return pStmt ? ((Vdbe*)pStmt)->readOnly : 1;
+}
+
+/*
+** Return 1 if the statement is an EXPLAIN and return 2 if the
+** statement is an EXPLAIN QUERY PLAN
+*/
+SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt){
+  return pStmt ? ((Vdbe*)pStmt)->explain : 0;
+}
+
+/*
+** Set the explain mode for a statement.
+*/
+SQLITE_API int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode){
+  Vdbe *v = (Vdbe*)pStmt;
+  int rc;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pStmt==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(v->db->mutex);
+  if( ((int)v->explain)==eMode ){
+    rc = SQLITE_OK;
+  }else if( eMode<0 || eMode>2 ){
+    rc = SQLITE_ERROR;
+  }else if( (v->prepFlags & SQLITE_PREPARE_SAVESQL)==0 ){
+    rc = SQLITE_ERROR;
+  }else if( v->eVdbeState!=VDBE_READY_STATE ){
+    rc = SQLITE_BUSY;
+  }else if( v->nMem>=10 && (eMode!=2 || v->haveEqpOps) ){
+    /* No reprepare necessary */
+    v->explain = eMode;
+    rc = SQLITE_OK;
+  }else{
+    v->explain = eMode;
+    rc = sqlite3Reprepare(v);
+    v->haveEqpOps = eMode==2;
+  }
+  if( v->explain ){
+    v->nResColumn = 12 - 4*v->explain;
+  }else{
+    v->nResColumn = v->nResAlloc;
+  }
+  sqlite3_mutex_leave(v->db->mutex);
+  return rc;
+}
+
+/*
+** Return true if the prepared statement is in need of being reset.
+*/
+SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt *pStmt){
+  Vdbe *v = (Vdbe*)pStmt;
+  return v!=0 && v->eVdbeState==VDBE_RUN_STATE;
+}
+
+/*
+** Return a pointer to the next prepared statement after pStmt associated
+** with database connection pDb.  If pStmt is NULL, return the first
+** prepared statement for the database connection.  Return NULL if there
+** are no more.
+*/
+SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt){
+  sqlite3_stmt *pNext;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(pDb) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(pDb->mutex);
+  if( pStmt==0 ){
+    pNext = (sqlite3_stmt*)pDb->pVdbe;
+  }else{
+    pNext = (sqlite3_stmt*)((Vdbe*)pStmt)->pVNext;
+  }
+  sqlite3_mutex_leave(pDb->mutex);
+  return pNext;
+}
+
+/*
+** Return the value of a status counter for a prepared statement
+*/
+SQLITE_API int sqlite3_stmt_status(sqlite3_stmt *pStmt, int op, int resetFlag){
+  Vdbe *pVdbe = (Vdbe*)pStmt;
+  u32 v;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !pStmt
+   || (op!=SQLITE_STMTSTATUS_MEMUSED && (op<0||op>=ArraySize(pVdbe->aCounter)))
+  ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  if( op==SQLITE_STMTSTATUS_MEMUSED ){
+    sqlite3 *db = pVdbe->db;
+    sqlite3_mutex_enter(db->mutex);
+    v = 0;
+    db->pnBytesFreed = (int*)&v;
+    assert( db->lookaside.pEnd==db->lookaside.pTrueEnd );
+    db->lookaside.pEnd = db->lookaside.pStart;
+    sqlite3VdbeDelete(pVdbe);
+    db->pnBytesFreed = 0;
+    db->lookaside.pEnd = db->lookaside.pTrueEnd;
+    sqlite3_mutex_leave(db->mutex);
+  }else{
+    v = pVdbe->aCounter[op];
+    if( resetFlag ) pVdbe->aCounter[op] = 0;
+  }
+  return (int)v;
+}
+
+/*
+** Return the SQL associated with a prepared statement
+*/
+SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe *)pStmt;
+  return p ? p->zSql : 0;
+}
+
+/*
+** Return the SQL associated with a prepared statement with
+** bound parameters expanded.  Space to hold the returned string is
+** obtained from sqlite3_malloc().  The caller is responsible for
+** freeing the returned string by passing it to sqlite3_free().
+**
+** The SQLITE_TRACE_SIZE_LIMIT puts an upper bound on the size of
+** expanded bound parameters.
+*/
+SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt){
+#ifdef SQLITE_OMIT_TRACE
+  return 0;
+#else
+  char *z = 0;
+  const char *zSql = sqlite3_sql(pStmt);
+  if( zSql ){
+    Vdbe *p = (Vdbe *)pStmt;
+    sqlite3_mutex_enter(p->db->mutex);
+    z = sqlite3VdbeExpandSql(p, zSql);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return z;
+#endif
+}
+
+#ifdef SQLITE_ENABLE_NORMALIZE
+/*
+** Return the normalized SQL associated with a prepared statement.
+*/
+SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe *)pStmt;
+  if( p==0 ) return 0;
+  if( p->zNormSql==0 && ALWAYS(p->zSql!=0) ){
+    sqlite3_mutex_enter(p->db->mutex);
+    p->zNormSql = sqlite3Normalize(p, p->zSql);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return p->zNormSql;
+}
+#endif /* SQLITE_ENABLE_NORMALIZE */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** Allocate and populate an UnpackedRecord structure based on the serialized
+** record in nKey/pKey. Return a pointer to the new UnpackedRecord structure
+** if successful, or a NULL pointer if an OOM error is encountered.
+*/
+static UnpackedRecord *vdbeUnpackRecord(
+  KeyInfo *pKeyInfo,
+  int nKey,
+  const void *pKey
+){
+  UnpackedRecord *pRet;           /* Return value */
+
+  pRet = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
+  if( pRet ){
+    memset(pRet->aMem, 0, sizeof(Mem)*(pKeyInfo->nKeyField+1));
+    sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, pRet);
+  }
+  return pRet;
+}
+
+/*
+** This function is called from within a pre-update callback to retrieve
+** a field of the row currently being updated or deleted.
+*/
+SQLITE_API int sqlite3_preupdate_old(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
+  PreUpdate *p;
+  Mem *pMem;
+  int rc = SQLITE_OK;
+  int iStore = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( db==0 || ppValue==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  p = db->pPreUpdate;
+  /* Test that this call is being made from within an SQLITE_DELETE or
+  ** SQLITE_UPDATE pre-update callback, and that iIdx is within range. */
+  if( !p || p->op==SQLITE_INSERT ){
+    rc = SQLITE_MISUSE_BKPT;
+    goto preupdate_old_out;
+  }
+  if( p->pPk ){
+    iStore = sqlite3TableColumnToIndex(p->pPk, iIdx);
+  }else{
+    iStore = sqlite3TableColumnToStorage(p->pTab, iIdx);
+  }
+  if( iStore>=p->pCsr->nField || iStore<0 ){
+    rc = SQLITE_RANGE;
+    goto preupdate_old_out;
+  }
+
+  if( iIdx==p->pTab->iPKey ){
+    *ppValue = pMem = &p->oldipk;
+    sqlite3VdbeMemSetInt64(pMem, p->iKey1);
+  }else{
+
+    /* If the old.* record has not yet been loaded into memory, do so now. */
+    if( p->pUnpacked==0 ){
+      u32 nRec;
+      u8 *aRec;
+
+      assert( p->pCsr->eCurType==CURTYPE_BTREE );
+      nRec = sqlite3BtreePayloadSize(p->pCsr->uc.pCursor);
+      aRec = sqlite3DbMallocRaw(db, nRec);
+      if( !aRec ) goto preupdate_old_out;
+      rc = sqlite3BtreePayload(p->pCsr->uc.pCursor, 0, nRec, aRec);
+      if( rc==SQLITE_OK ){
+        p->pUnpacked = vdbeUnpackRecord(&p->keyinfo, nRec, aRec);
+        if( !p->pUnpacked ) rc = SQLITE_NOMEM;
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3DbFree(db, aRec);
+        goto preupdate_old_out;
+      }
+      p->aRecord = aRec;
+    }
+
+    pMem = *ppValue = &p->pUnpacked->aMem[iStore];
+    if( iStore>=p->pUnpacked->nField ){
+      /* This occurs when the table has been extended using ALTER TABLE
+      ** ADD COLUMN. The value to return is the default value of the column. */
+      Column *pCol = &p->pTab->aCol[iIdx];
+      if( pCol->iDflt>0 ){
+        if( p->apDflt==0 ){
+          int nByte = sizeof(sqlite3_value*)*p->pTab->nCol;
+          p->apDflt = (sqlite3_value**)sqlite3DbMallocZero(db, nByte);
+          if( p->apDflt==0 ) goto preupdate_old_out;
+        }
+        if( p->apDflt[iIdx]==0 ){
+          sqlite3_value *pVal = 0;
+          Expr *pDflt;
+          assert( p->pTab!=0 && IsOrdinaryTable(p->pTab) );
+          pDflt = p->pTab->u.tab.pDfltList->a[pCol->iDflt-1].pExpr;
+          rc = sqlite3ValueFromExpr(db, pDflt, ENC(db), pCol->affinity, &pVal);
+          if( rc==SQLITE_OK && pVal==0 ){
+            rc = SQLITE_CORRUPT_BKPT;
+          }
+          p->apDflt[iIdx] = pVal;
+        }
+        *ppValue = p->apDflt[iIdx];
+      }else{
+        *ppValue = (sqlite3_value *)columnNullValue();
+      }
+    }else if( p->pTab->aCol[iIdx].affinity==SQLITE_AFF_REAL ){
+      if( pMem->flags & (MEM_Int|MEM_IntReal) ){
+        testcase( pMem->flags & MEM_Int );
+        testcase( pMem->flags & MEM_IntReal );
+        sqlite3VdbeMemRealify(pMem);
+      }
+    }
+  }
+
+ preupdate_old_out:
+  sqlite3Error(db, rc);
+  return sqlite3ApiExit(db, rc);
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** This function is called from within a pre-update callback to retrieve
+** the number of columns in the row being updated, deleted or inserted.
+*/
+SQLITE_API int sqlite3_preupdate_count(sqlite3 *db){
+  PreUpdate *p;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  p = db!=0 ? db->pPreUpdate : 0;
+#else
+  p = db->pPreUpdate;
+#endif
+  return (p ? p->keyinfo.nKeyField : 0);
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** This function is designed to be called from within a pre-update callback
+** only. It returns zero if the change that caused the callback was made
+** immediately by a user SQL statement. Or, if the change was made by a
+** trigger program, it returns the number of trigger programs currently
+** on the stack (1 for a top-level trigger, 2 for a trigger fired by a
+** top-level trigger etc.).
+**
+** For the purposes of the previous paragraph, a foreign key CASCADE, SET NULL
+** or SET DEFAULT action is considered a trigger.
+*/
+SQLITE_API int sqlite3_preupdate_depth(sqlite3 *db){
+  PreUpdate *p;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  p = db!=0 ? db->pPreUpdate : 0;
+#else
+  p = db->pPreUpdate;
+#endif
+  return (p ? p->v->nFrame : 0);
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** This function is designed to be called from within a pre-update callback
+** only.
+*/
+SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *db){
+  PreUpdate *p;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  p = db!=0 ? db->pPreUpdate : 0;
+#else
+  p = db->pPreUpdate;
+#endif
+  return (p ? p->iBlobWrite : -1);
+}
+#endif
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** This function is called from within a pre-update callback to retrieve
+** a field of the row currently being updated or inserted.
+*/
+SQLITE_API int sqlite3_preupdate_new(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
+  PreUpdate *p;
+  int rc = SQLITE_OK;
+  Mem *pMem;
+  int iStore = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( db==0 || ppValue==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  p = db->pPreUpdate;
+  if( !p || p->op==SQLITE_DELETE ){
+    rc = SQLITE_MISUSE_BKPT;
+    goto preupdate_new_out;
+  }
+  if( p->pPk && p->op!=SQLITE_UPDATE ){
+    iStore = sqlite3TableColumnToIndex(p->pPk, iIdx);
+  }else{
+    iStore = sqlite3TableColumnToStorage(p->pTab, iIdx);
+  }
+
+  if( iStore>=p->pCsr->nField || iStore<0 ){
+    rc = SQLITE_RANGE;
+    goto preupdate_new_out;
+  }
+
+  if( p->op==SQLITE_INSERT ){
+    /* For an INSERT, memory cell p->iNewReg contains the serialized record
+    ** that is being inserted. Deserialize it. */
+    UnpackedRecord *pUnpack = p->pNewUnpacked;
+    if( !pUnpack ){
+      Mem *pData = &p->v->aMem[p->iNewReg];
+      rc = ExpandBlob(pData);
+      if( rc!=SQLITE_OK ) goto preupdate_new_out;
+      pUnpack = vdbeUnpackRecord(&p->keyinfo, pData->n, pData->z);
+      if( !pUnpack ){
+        rc = SQLITE_NOMEM;
+        goto preupdate_new_out;
+      }
+      p->pNewUnpacked = pUnpack;
+    }
+    pMem = &pUnpack->aMem[iStore];
+    if( iIdx==p->pTab->iPKey ){
+      sqlite3VdbeMemSetInt64(pMem, p->iKey2);
+    }else if( iStore>=pUnpack->nField ){
+      pMem = (sqlite3_value *)columnNullValue();
+    }
+  }else{
+    /* For an UPDATE, memory cell (p->iNewReg+1+iStore) contains the required
+    ** value. Make a copy of the cell contents and return a pointer to it.
+    ** It is not safe to return a pointer to the memory cell itself as the
+    ** caller may modify the value text encoding.
+    */
+    assert( p->op==SQLITE_UPDATE );
+    if( !p->aNew ){
+      p->aNew = (Mem *)sqlite3DbMallocZero(db, sizeof(Mem) * p->pCsr->nField);
+      if( !p->aNew ){
+        rc = SQLITE_NOMEM;
+        goto preupdate_new_out;
+      }
+    }
+    assert( iStore>=0 && iStore<p->pCsr->nField );
+    pMem = &p->aNew[iStore];
+    if( pMem->flags==0 ){
+      if( iIdx==p->pTab->iPKey ){
+        sqlite3VdbeMemSetInt64(pMem, p->iKey2);
+      }else{
+        rc = sqlite3VdbeMemCopy(pMem, &p->v->aMem[p->iNewReg+1+iStore]);
+        if( rc!=SQLITE_OK ) goto preupdate_new_out;
+      }
+    }
+  }
+  *ppValue = pMem;
+
+ preupdate_new_out:
+  sqlite3Error(db, rc);
+  return sqlite3ApiExit(db, rc);
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+/*
+** Return status data for a single loop within query pStmt.
+*/
+SQLITE_API int sqlite3_stmt_scanstatus_v2(
+  sqlite3_stmt *pStmt,            /* Prepared statement being queried */
+  int iScan,                      /* Index of loop to report on */
+  int iScanStatusOp,              /* Which metric to return */
+  int flags,
+  void *pOut                      /* OUT: Write the answer here */
+){
+  Vdbe *p = (Vdbe*)pStmt;
+  VdbeOp *aOp;
+  int nOp;
+  ScanStatus *pScan = 0;
+  int idx;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 || pOut==0
+      || iScanStatusOp<SQLITE_SCANSTAT_NLOOP
+      || iScanStatusOp>SQLITE_SCANSTAT_NCYCLE ){
+    return 1;
+  }
+#endif
+  aOp = p->aOp;
+  nOp = p->nOp;
+  if( p->pFrame ){
+    VdbeFrame *pFrame;
+    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
+    aOp = pFrame->aOp;
+    nOp = pFrame->nOp;
+  }
+
+  if( iScan<0 ){
+    int ii;
+    if( iScanStatusOp==SQLITE_SCANSTAT_NCYCLE ){
+      i64 res = 0;
+      for(ii=0; ii<nOp; ii++){
+        res += aOp[ii].nCycle;
+      }
+      *(i64*)pOut = res;
+      return 0;
+    }
+    return 1;
+  }
+  if( flags & SQLITE_SCANSTAT_COMPLEX ){
+    idx = iScan;
+  }else{
+    /* If the COMPLEX flag is clear, then this function must ignore any
+    ** ScanStatus structures with ScanStatus.addrLoop set to 0. */
+    for(idx=0; idx<p->nScan; idx++){
+      pScan = &p->aScan[idx];
+      if( pScan->zName ){
+        iScan--;
+        if( iScan<0 ) break;
+      }
+    }
+  }
+  if( idx>=p->nScan ) return 1;
+  assert( pScan==0 || pScan==&p->aScan[idx] );
+  pScan = &p->aScan[idx];
+
+  switch( iScanStatusOp ){
+    case SQLITE_SCANSTAT_NLOOP: {
+      if( pScan->addrLoop>0 ){
+        *(sqlite3_int64*)pOut = aOp[pScan->addrLoop].nExec;
+      }else{
+        *(sqlite3_int64*)pOut = -1;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_NVISIT: {
+      if( pScan->addrVisit>0 ){
+        *(sqlite3_int64*)pOut = aOp[pScan->addrVisit].nExec;
+      }else{
+        *(sqlite3_int64*)pOut = -1;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_EST: {
+      double r = 1.0;
+      LogEst x = pScan->nEst;
+      while( x<100 ){
+        x += 10;
+        r *= 0.5;
+      }
+      *(double*)pOut = r*sqlite3LogEstToInt(x);
+      break;
+    }
+    case SQLITE_SCANSTAT_NAME: {
+      *(const char**)pOut = pScan->zName;
+      break;
+    }
+    case SQLITE_SCANSTAT_EXPLAIN: {
+      if( pScan->addrExplain ){
+        *(const char**)pOut = aOp[ pScan->addrExplain ].p4.z;
+      }else{
+        *(const char**)pOut = 0;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_SELECTID: {
+      if( pScan->addrExplain ){
+        *(int*)pOut = aOp[ pScan->addrExplain ].p1;
+      }else{
+        *(int*)pOut = -1;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_PARENTID: {
+      if( pScan->addrExplain ){
+        *(int*)pOut = aOp[ pScan->addrExplain ].p2;
+      }else{
+        *(int*)pOut = -1;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_NCYCLE: {
+      i64 res = 0;
+      if( pScan->aAddrRange[0]==0 ){
+        res = -1;
+      }else{
+        int ii;
+        for(ii=0; ii<ArraySize(pScan->aAddrRange); ii+=2){
+          int iIns = pScan->aAddrRange[ii];
+          int iEnd = pScan->aAddrRange[ii+1];
+          if( iIns==0 ) break;
+          if( iIns>0 ){
+            while( iIns<=iEnd ){
+              res += aOp[iIns].nCycle;
+              iIns++;
+            }
+          }else{
+            int iOp;
+            for(iOp=0; iOp<nOp; iOp++){
+              Op *pOp = &aOp[iOp];
+              if( pOp->p1!=iEnd ) continue;
+              if( (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_NCYCLE)==0 ){
+                continue;
+              }
+              res += aOp[iOp].nCycle;
+            }
+          }
+        }
+      }
+      *(i64*)pOut = res;
+      break;
+    }
+    default: {
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Return status data for a single loop within query pStmt.
+*/
+SQLITE_API int sqlite3_stmt_scanstatus(
+  sqlite3_stmt *pStmt,            /* Prepared statement being queried */
+  int iScan,                      /* Index of loop to report on */
+  int iScanStatusOp,              /* Which metric to return */
+  void *pOut                      /* OUT: Write the answer here */
+){
+  return sqlite3_stmt_scanstatus_v2(pStmt, iScan, iScanStatusOp, 0, pOut);
+}
+
+/*
+** Zero all counters associated with the sqlite3_stmt_scanstatus() data.
+*/
+SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe*)pStmt;
+  int ii;
+  for(ii=0; p!=0 && ii<p->nOp; ii++){
+    Op *pOp = &p->aOp[ii];
+    pOp->nExec = 0;
+    pOp->nCycle = 0;
+  }
+}
+#endif /* SQLITE_ENABLE_STMT_SCANSTATUS */
+
+/************** End of vdbeapi.c *********************************************/
+/************** Begin file vdbetrace.c ***************************************/
+/*
+** 2009 November 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code used to insert the values of host parameters
+** (aka "wildcards") into the SQL text output by sqlite3_trace().
+**
+** The Vdbe parse-tree explainer is also found here.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+#ifndef SQLITE_OMIT_TRACE
+
+/*
+** zSql is a zero-terminated string of UTF-8 SQL text.  Return the number of
+** bytes in this text up to but excluding the first character in
+** a host parameter.  If the text contains no host parameters, return
+** the total number of bytes in the text.
+*/
+static int findNextHostParameter(const char *zSql, int *pnToken){
+  int tokenType;
+  int nTotal = 0;
+  int n;
+
+  *pnToken = 0;
+  while( zSql[0] ){
+    n = sqlite3GetToken((u8*)zSql, &tokenType);
+    assert( n>0 && tokenType!=TK_ILLEGAL );
+    if( tokenType==TK_VARIABLE ){
+      *pnToken = n;
+      break;
+    }
+    nTotal += n;
+    zSql += n;
+  }
+  return nTotal;
+}
+
+/*
+** This function returns a pointer to a nul-terminated string in memory
+** obtained from sqlite3DbMalloc(). If sqlite3.nVdbeExec is 1, then the
+** string contains a copy of zRawSql but with host parameters expanded to
+** their current bindings. Or, if sqlite3.nVdbeExec is greater than 1,
+** then the returned string holds a copy of zRawSql with "-- " prepended
+** to each line of text.
+**
+** If the SQLITE_TRACE_SIZE_LIMIT macro is defined to an integer, then
+** then long strings and blobs are truncated to that many bytes.  This
+** can be used to prevent unreasonably large trace strings when dealing
+** with large (multi-megabyte) strings and blobs.
+**
+** The calling function is responsible for making sure the memory returned
+** is eventually freed.
+**
+** ALGORITHM:  Scan the input string looking for host parameters in any of
+** these forms:  ?, ?N, $A, @A, :A.  Take care to avoid text within
+** string literals, quoted identifier names, and comments.  For text forms,
+** the host parameter index is found by scanning the prepared
+** statement for the corresponding OP_Variable opcode.  Once the host
+** parameter index is known, locate the value in p->aVar[].  Then render
+** the value as a literal in place of the host parameter name.
+*/
+SQLITE_PRIVATE char *sqlite3VdbeExpandSql(
+  Vdbe *p,                 /* The prepared statement being evaluated */
+  const char *zRawSql      /* Raw text of the SQL statement */
+){
+  sqlite3 *db;             /* The database connection */
+  int idx = 0;             /* Index of a host parameter */
+  int nextIndex = 1;       /* Index of next ? host parameter */
+  int n;                   /* Length of a token prefix */
+  int nToken;              /* Length of the parameter token */
+  int i;                   /* Loop counter */
+  Mem *pVar;               /* Value of a host parameter */
+  StrAccum out;            /* Accumulate the output here */
+#ifndef SQLITE_OMIT_UTF16
+  Mem utf8;                /* Used to convert UTF16 into UTF8 for display */
+#endif
+
+  db = p->db;
+  sqlite3StrAccumInit(&out, 0, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
+  if( db->nVdbeExec>1 ){
+    while( *zRawSql ){
+      const char *zStart = zRawSql;
+      while( *(zRawSql++)!='\n' && *zRawSql );
+      sqlite3_str_append(&out, "-- ", 3);
+      assert( (zRawSql - zStart) > 0 );
+      sqlite3_str_append(&out, zStart, (int)(zRawSql-zStart));
+    }
+  }else if( p->nVar==0 ){
+    sqlite3_str_append(&out, zRawSql, sqlite3Strlen30(zRawSql));
+  }else{
+    while( zRawSql[0] ){
+      n = findNextHostParameter(zRawSql, &nToken);
+      assert( n>0 );
+      sqlite3_str_append(&out, zRawSql, n);
+      zRawSql += n;
+      assert( zRawSql[0] || nToken==0 );
+      if( nToken==0 ) break;
+      if( zRawSql[0]=='?' ){
+        if( nToken>1 ){
+          assert( sqlite3Isdigit(zRawSql[1]) );
+          sqlite3GetInt32(&zRawSql[1], &idx);
+        }else{
+          idx = nextIndex;
+        }
+      }else{
+        assert( zRawSql[0]==':' || zRawSql[0]=='$' ||
+                zRawSql[0]=='@' || zRawSql[0]=='#' );
+        testcase( zRawSql[0]==':' );
+        testcase( zRawSql[0]=='$' );
+        testcase( zRawSql[0]=='@' );
+        testcase( zRawSql[0]=='#' );
+        idx = sqlite3VdbeParameterIndex(p, zRawSql, nToken);
+        assert( idx>0 );
+      }
+      zRawSql += nToken;
+      nextIndex = MAX(idx + 1, nextIndex);
+      assert( idx>0 && idx<=p->nVar );
+      pVar = &p->aVar[idx-1];
+      if( pVar->flags & MEM_Null ){
+        sqlite3_str_append(&out, "NULL", 4);
+      }else if( pVar->flags & (MEM_Int|MEM_IntReal) ){
+        sqlite3_str_appendf(&out, "%lld", pVar->u.i);
+      }else if( pVar->flags & MEM_Real ){
+        sqlite3_str_appendf(&out, "%!.15g", pVar->u.r);
+      }else if( pVar->flags & MEM_Str ){
+        int nOut;  /* Number of bytes of the string text to include in output */
+#ifndef SQLITE_OMIT_UTF16
+        u8 enc = ENC(db);
+        if( enc!=SQLITE_UTF8 ){
+          memset(&utf8, 0, sizeof(utf8));
+          utf8.db = db;
+          sqlite3VdbeMemSetStr(&utf8, pVar->z, pVar->n, enc, SQLITE_STATIC);
+          if( SQLITE_NOMEM==sqlite3VdbeChangeEncoding(&utf8, SQLITE_UTF8) ){
+            out.accError = SQLITE_NOMEM;
+            out.nAlloc = 0;
+          }
+          pVar = &utf8;
+        }
+#endif
+        nOut = pVar->n;
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut>SQLITE_TRACE_SIZE_LIMIT ){
+          nOut = SQLITE_TRACE_SIZE_LIMIT;
+          while( nOut<pVar->n && (pVar->z[nOut]&0xc0)==0x80 ){ nOut++; }
+        }
+#endif
+        sqlite3_str_appendf(&out, "'%.*q'", nOut, pVar->z);
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut<pVar->n ){
+          sqlite3_str_appendf(&out, "/*+%d bytes*/", pVar->n-nOut);
+        }
+#endif
+#ifndef SQLITE_OMIT_UTF16
+        if( enc!=SQLITE_UTF8 ) sqlite3VdbeMemRelease(&utf8);
+#endif
+      }else if( pVar->flags & MEM_Zero ){
+        sqlite3_str_appendf(&out, "zeroblob(%d)", pVar->u.nZero);
+      }else{
+        int nOut;  /* Number of bytes of the blob to include in output */
+        assert( pVar->flags & MEM_Blob );
+        sqlite3_str_append(&out, "x'", 2);
+        nOut = pVar->n;
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut>SQLITE_TRACE_SIZE_LIMIT ) nOut = SQLITE_TRACE_SIZE_LIMIT;
+#endif
+        for(i=0; i<nOut; i++){
+          sqlite3_str_appendf(&out, "%02x", pVar->z[i]&0xff);
+        }
+        sqlite3_str_append(&out, "'", 1);
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut<pVar->n ){
+          sqlite3_str_appendf(&out, "/*+%d bytes*/", pVar->n-nOut);
+        }
+#endif
+      }
+    }
+  }
+  if( out.accError ) sqlite3_str_reset(&out);
+  return sqlite3StrAccumFinish(&out);
+}
+
+#endif /* #ifndef SQLITE_OMIT_TRACE */
+
+/************** End of vdbetrace.c *******************************************/
+/************** Begin file vdbe.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** The code in this file implements the function that runs the
+** bytecode of a prepared statement.
+**
+** Various scripts scan this source file in order to generate HTML
+** documentation, headers files, or other derived files.  The formatting
+** of the code in this file is, therefore, important.  See other comments
+** in this file for details.  If in doubt, do not deviate from existing
+** commenting and indentation practices when changing or adding code.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+/*
+** High-resolution hardware timer used for debugging and testing only.
+*/
+#if defined(VDBE_PROFILE)  \
+ || defined(SQLITE_PERFORMANCE_TRACE) \
+ || defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+/************** Include hwtime.h in the middle of vdbe.c *********************/
+/************** Begin file hwtime.h ******************************************/
+/*
+** 2008 May 27
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains inline asm code for retrieving "high-performance"
+** counters for x86 and x86_64 class CPUs.
+*/
+#ifndef SQLITE_HWTIME_H
+#define SQLITE_HWTIME_H
+
+/*
+** The following routine only works on Pentium-class (or newer) processors.
+** It uses the RDTSC opcode to read the cycle count value out of the
+** processor and returns that value.  This can be used for high-res
+** profiling.
+*/
+#if !defined(__STRICT_ANSI__) && \
+    (defined(__GNUC__) || defined(_MSC_VER)) && \
+    (defined(i386) || defined(__i386__) || defined(_M_IX86))
+
+  #if defined(__GNUC__)
+
+  __inline__ sqlite_uint64 sqlite3Hwtime(void){
+     unsigned int lo, hi;
+     __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
+     return (sqlite_uint64)hi << 32 | lo;
+  }
+
+  #elif defined(_MSC_VER)
+
+  __declspec(naked) __inline sqlite_uint64 __cdecl sqlite3Hwtime(void){
+     __asm {
+        rdtsc
+        ret       ; return value at EDX:EAX
+     }
+  }
+
+  #endif
+
+#elif !defined(__STRICT_ANSI__) && (defined(__GNUC__) && defined(__x86_64__))
+
+  __inline__ sqlite_uint64 sqlite3Hwtime(void){
+     unsigned int lo, hi;
+     __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
+     return (sqlite_uint64)hi << 32 | lo;
+  }
+
+#elif !defined(__STRICT_ANSI__) && (defined(__GNUC__) && defined(__ppc__))
+
+  __inline__ sqlite_uint64 sqlite3Hwtime(void){
+      unsigned long long retval;
+      unsigned long junk;
+      __asm__ __volatile__ ("\n\
+          1:      mftbu   %1\n\
+                  mftb    %L0\n\
+                  mftbu   %0\n\
+                  cmpw    %0,%1\n\
+                  bne     1b"
+                  : "=r" (retval), "=r" (junk));
+      return retval;
+  }
+
+#else
+
+  /*
+  ** asm() is needed for hardware timing support.  Without asm(),
+  ** disable the sqlite3Hwtime() routine.
+  **
+  ** sqlite3Hwtime() is only used for some obscure debugging
+  ** and analysis configurations, not in any deliverable, so this
+  ** should not be a great loss.
+  */
+SQLITE_PRIVATE   sqlite_uint64 sqlite3Hwtime(void){ return ((sqlite_uint64)0); }
+
+#endif
+
+#endif /* !defined(SQLITE_HWTIME_H) */
+
+/************** End of hwtime.h **********************************************/
+/************** Continuing where we left off in vdbe.c ***********************/
+#endif
+
+/*
+** Invoke this macro on memory cells just prior to changing the
+** value of the cell.  This macro verifies that shallow copies are
+** not misused.  A shallow copy of a string or blob just copies a
+** pointer to the string or blob, not the content.  If the original
+** is changed while the copy is still in use, the string or blob might
+** be changed out from under the copy.  This macro verifies that nothing
+** like that ever happens.
+*/
+#ifdef SQLITE_DEBUG
+# define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
+#else
+# define memAboutToChange(P,M)
+#endif
+
+/*
+** The following global variable is incremented every time a cursor
+** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
+** procedures use this information to make sure that indices are
+** working correctly.  This variable has no function other than to
+** help verify the correct operation of the library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_search_count = 0;
+#endif
+
+/*
+** When this global variable is positive, it gets decremented once before
+** each instruction in the VDBE.  When it reaches zero, the u1.isInterrupted
+** field of the sqlite3 structure is set in order to simulate an interrupt.
+**
+** This facility is used for testing purposes only.  It does not function
+** in an ordinary build.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_interrupt_count = 0;
+#endif
+
+/*
+** The next global variable is incremented each type the OP_Sort opcode
+** is executed.  The test procedures use this information to make sure that
+** sorting is occurring or not occurring at appropriate times.   This variable
+** has no function other than to help verify the correct operation of the
+** library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_sort_count = 0;
+#endif
+
+/*
+** The next global variable records the size of the largest MEM_Blob
+** or MEM_Str that has been used by a VDBE opcode.  The test procedures
+** use this information to make sure that the zero-blob functionality
+** is working correctly.   This variable has no function other than to
+** help verify the correct operation of the library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_max_blobsize = 0;
+static void updateMaxBlobsize(Mem *p){
+  if( (p->flags & (MEM_Str|MEM_Blob))!=0 && p->n>sqlite3_max_blobsize ){
+    sqlite3_max_blobsize = p->n;
+  }
+}
+#endif
+
+/*
+** This macro evaluates to true if either the update hook or the preupdate
+** hook are enabled for database connect DB.
+*/
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+# define HAS_UPDATE_HOOK(DB) ((DB)->xPreUpdateCallback||(DB)->xUpdateCallback)
+#else
+# define HAS_UPDATE_HOOK(DB) ((DB)->xUpdateCallback)
+#endif
+
+/*
+** The next global variable is incremented each time the OP_Found opcode
+** is executed. This is used to test whether or not the foreign key
+** operation implemented using OP_FkIsZero is working. This variable
+** has no function other than to help verify the correct operation of the
+** library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_found_count = 0;
+#endif
+
+/*
+** Test a register to see if it exceeds the current maximum blob size.
+** If it does, record the new maximum blob size.
+*/
+#if defined(SQLITE_TEST) && !defined(SQLITE_UNTESTABLE)
+# define UPDATE_MAX_BLOBSIZE(P)  updateMaxBlobsize(P)
+#else
+# define UPDATE_MAX_BLOBSIZE(P)
+#endif
+
+#ifdef SQLITE_DEBUG
+/* This routine provides a convenient place to set a breakpoint during
+** tracing with PRAGMA vdbe_trace=on.  The breakpoint fires right after
+** each opcode is printed.  Variables "pc" (program counter) and pOp are
+** available to add conditionals to the breakpoint.  GDB example:
+**
+**         break test_trace_breakpoint if pc=22
+**
+** Other useful labels for breakpoints include:
+**   test_addop_breakpoint(pc,pOp)
+**   sqlite3CorruptError(lineno)
+**   sqlite3MisuseError(lineno)
+**   sqlite3CantopenError(lineno)
+*/
+static void test_trace_breakpoint(int pc, Op *pOp, Vdbe *v){
+  static u64 n = 0;
+  (void)pc;
+  (void)pOp;
+  (void)v;
+  n++;
+  if( n==LARGEST_UINT64 ) abort(); /* So that n is used, preventing a warning */
+}
+#endif
+
+/*
+** Invoke the VDBE coverage callback, if that callback is defined.  This
+** feature is used for test suite validation only and does not appear an
+** production builds.
+**
+** M is the type of branch.  I is the direction taken for this instance of
+** the branch.
+**
+**   M: 2 - two-way branch (I=0: fall-thru   1: jump                )
+**      3 - two-way + NULL (I=0: fall-thru   1: jump      2: NULL   )
+**      4 - OP_Jump        (I=0: jump p1     1: jump p2   2: jump p3)
+**
+** In other words, if M is 2, then I is either 0 (for fall-through) or
+** 1 (for when the branch is taken).  If M is 3, the I is 0 for an
+** ordinary fall-through, I is 1 if the branch was taken, and I is 2
+** if the result of comparison is NULL.  For M=3, I=2 the jump may or
+** may not be taken, depending on the SQLITE_JUMPIFNULL flags in p5.
+** When M is 4, that means that an OP_Jump is being run.  I is 0, 1, or 2
+** depending on if the operands are less than, equal, or greater than.
+**
+** iSrcLine is the source code line (from the __LINE__ macro) that
+** generated the VDBE instruction combined with flag bits.  The source
+** code line number is in the lower 24 bits of iSrcLine and the upper
+** 8 bytes are flags.  The lower three bits of the flags indicate
+** values for I that should never occur.  For example, if the branch is
+** always taken, the flags should be 0x05 since the fall-through and
+** alternate branch are never taken.  If a branch is never taken then
+** flags should be 0x06 since only the fall-through approach is allowed.
+**
+** Bit 0x08 of the flags indicates an OP_Jump opcode that is only
+** interested in equal or not-equal.  In other words, I==0 and I==2
+** should be treated as equivalent
+**
+** Since only a line number is retained, not the filename, this macro
+** only works for amalgamation builds.  But that is ok, since these macros
+** should be no-ops except for special builds used to measure test coverage.
+*/
+#if !defined(SQLITE_VDBE_COVERAGE)
+# define VdbeBranchTaken(I,M)
+#else
+# define VdbeBranchTaken(I,M) vdbeTakeBranch(pOp->iSrcLine,I,M)
+  static void vdbeTakeBranch(u32 iSrcLine, u8 I, u8 M){
+    u8 mNever;
+    assert( I<=2 );  /* 0: fall through,  1: taken,  2: alternate taken */
+    assert( M<=4 );  /* 2: two-way branch, 3: three-way branch, 4: OP_Jump */
+    assert( I<M );   /* I can only be 2 if M is 3 or 4 */
+    /* Transform I from a integer [0,1,2] into a bitmask of [1,2,4] */
+    I = 1<<I;
+    /* The upper 8 bits of iSrcLine are flags.  The lower three bits of
+    ** the flags indicate directions that the branch can never go.  If
+    ** a branch really does go in one of those directions, assert right
+    ** away. */
+    mNever = iSrcLine >> 24;
+    assert( (I & mNever)==0 );
+    if( sqlite3GlobalConfig.xVdbeBranch==0 ) return;  /*NO_TEST*/
+    /* Invoke the branch coverage callback with three arguments:
+    **    iSrcLine - the line number of the VdbeCoverage() macro, with
+    **               flags removed.
+    **    I        - Mask of bits 0x07 indicating which cases are are
+    **               fulfilled by this instance of the jump.  0x01 means
+    **               fall-thru, 0x02 means taken, 0x04 means NULL.  Any
+    **               impossible cases (ex: if the comparison is never NULL)
+    **               are filled in automatically so that the coverage
+    **               measurement logic does not flag those impossible cases
+    **               as missed coverage.
+    **    M        - Type of jump.  Same as M argument above
+    */
+    I |= mNever;
+    if( M==2 ) I |= 0x04;
+    if( M==4 ){
+      I |= 0x08;
+      if( (mNever&0x08)!=0 && (I&0x05)!=0) I |= 0x05; /*NO_TEST*/
+    }
+    sqlite3GlobalConfig.xVdbeBranch(sqlite3GlobalConfig.pVdbeBranchArg,
+                                    iSrcLine&0xffffff, I, M);
+  }
+#endif
+
+/*
+** An ephemeral string value (signified by the MEM_Ephem flag) contains
+** a pointer to a dynamically allocated string where some other entity
+** is responsible for deallocating that string.  Because the register
+** does not control the string, it might be deleted without the register
+** knowing it.
+**
+** This routine converts an ephemeral string into a dynamically allocated
+** string that the register itself controls.  In other words, it
+** converts an MEM_Ephem string into a string with P.z==P.zMalloc.
+*/
+#define Deephemeralize(P) \
+   if( ((P)->flags&MEM_Ephem)!=0 \
+       && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}
+
+/* Return true if the cursor was opened using the OP_OpenSorter opcode. */
+#define isSorter(x) ((x)->eCurType==CURTYPE_SORTER)
+
+/*
+** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
+** if we run out of memory.
+*/
+static VdbeCursor *allocateCursor(
+  Vdbe *p,              /* The virtual machine */
+  int iCur,             /* Index of the new VdbeCursor */
+  int nField,           /* Number of fields in the table or index */
+  u8 eCurType           /* Type of the new cursor */
+){
+  /* Find the memory cell that will be used to store the blob of memory
+  ** required for this VdbeCursor structure. It is convenient to use a
+  ** vdbe memory cell to manage the memory allocation required for a
+  ** VdbeCursor structure for the following reasons:
+  **
+  **   * Sometimes cursor numbers are used for a couple of different
+  **     purposes in a vdbe program. The different uses might require
+  **     different sized allocations. Memory cells provide growable
+  **     allocations.
+  **
+  **   * When using ENABLE_MEMORY_MANAGEMENT, memory cell buffers can
+  **     be freed lazily via the sqlite3_release_memory() API. This
+  **     minimizes the number of malloc calls made by the system.
+  **
+  ** The memory cell for cursor 0 is aMem[0]. The rest are allocated from
+  ** the top of the register space.  Cursor 1 is at Mem[p->nMem-1].
+  ** Cursor 2 is at Mem[p->nMem-2]. And so forth.
+  */
+  Mem *pMem = iCur>0 ? &p->aMem[p->nMem-iCur] : p->aMem;
+
+  int nByte;
+  VdbeCursor *pCx = 0;
+  nByte =
+      ROUND8P(sizeof(VdbeCursor)) + 2*sizeof(u32)*nField +
+      (eCurType==CURTYPE_BTREE?sqlite3BtreeCursorSize():0);
+
+  assert( iCur>=0 && iCur<p->nCursor );
+  if( p->apCsr[iCur] ){ /*OPTIMIZATION-IF-FALSE*/
+    sqlite3VdbeFreeCursorNN(p, p->apCsr[iCur]);
+    p->apCsr[iCur] = 0;
+  }
+
+  /* There used to be a call to sqlite3VdbeMemClearAndResize() to make sure
+  ** the pMem used to hold space for the cursor has enough storage available
+  ** in pMem->zMalloc.  But for the special case of the aMem[] entries used
+  ** to hold cursors, it is faster to in-line the logic. */
+  assert( pMem->flags==MEM_Undefined );
+  assert( (pMem->flags & MEM_Dyn)==0 );
+  assert( pMem->szMalloc==0 || pMem->z==pMem->zMalloc );
+  if( pMem->szMalloc<nByte ){
+    if( pMem->szMalloc>0 ){
+      sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
+    }
+    pMem->z = pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, nByte);
+    if( pMem->zMalloc==0 ){
+      pMem->szMalloc = 0;
+      return 0;
+    }
+    pMem->szMalloc = nByte;
+  }
+
+  p->apCsr[iCur] = pCx = (VdbeCursor*)pMem->zMalloc;
+  memset(pCx, 0, offsetof(VdbeCursor,pAltCursor));
+  pCx->eCurType = eCurType;
+  pCx->nField = nField;
+  pCx->aOffset = &pCx->aType[nField];
+  if( eCurType==CURTYPE_BTREE ){
+    pCx->uc.pCursor = (BtCursor*)
+        &pMem->z[ROUND8P(sizeof(VdbeCursor))+2*sizeof(u32)*nField];
+    sqlite3BtreeCursorZero(pCx->uc.pCursor);
+  }
+  return pCx;
+}
+
+/*
+** The string in pRec is known to look like an integer and to have a
+** floating point value of rValue.  Return true and set *piValue to the
+** integer value if the string is in range to be an integer.  Otherwise,
+** return false.
+*/
+static int alsoAnInt(Mem *pRec, double rValue, i64 *piValue){
+  i64 iValue;
+  iValue = sqlite3RealToI64(rValue);
+  if( sqlite3RealSameAsInt(rValue,iValue) ){
+    *piValue = iValue;
+    return 1;
+  }
+  return 0==sqlite3Atoi64(pRec->z, piValue, pRec->n, pRec->enc);
+}
+
+/*
+** Try to convert a value into a numeric representation if we can
+** do so without loss of information.  In other words, if the string
+** looks like a number, convert it into a number.  If it does not
+** look like a number, leave it alone.
+**
+** If the bTryForInt flag is true, then extra effort is made to give
+** an integer representation.  Strings that look like floating point
+** values but which have no fractional component (example: '48.00')
+** will have a MEM_Int representation when bTryForInt is true.
+**
+** If bTryForInt is false, then if the input string contains a decimal
+** point or exponential notation, the result is only MEM_Real, even
+** if there is an exact integer representation of the quantity.
+*/
+static void applyNumericAffinity(Mem *pRec, int bTryForInt){
+  double rValue;
+  u8 enc = pRec->enc;
+  int rc;
+  assert( (pRec->flags & (MEM_Str|MEM_Int|MEM_Real|MEM_IntReal))==MEM_Str );
+  rc = sqlite3AtoF(pRec->z, &rValue, pRec->n, enc);
+  if( rc<=0 ) return;
+  if( rc==1 && alsoAnInt(pRec, rValue, &pRec->u.i) ){
+    pRec->flags |= MEM_Int;
+  }else{
+    pRec->u.r = rValue;
+    pRec->flags |= MEM_Real;
+    if( bTryForInt ) sqlite3VdbeIntegerAffinity(pRec);
+  }
+  /* TEXT->NUMERIC is many->one.  Hence, it is important to invalidate the
+  ** string representation after computing a numeric equivalent, because the
+  ** string representation might not be the canonical representation for the
+  ** numeric value.  Ticket [343634942dd54ab57b7024] 2018-01-31. */
+  pRec->flags &= ~MEM_Str;
+}
+
+/*
+** Processing is determine by the affinity parameter:
+**
+** SQLITE_AFF_INTEGER:
+** SQLITE_AFF_REAL:
+** SQLITE_AFF_NUMERIC:
+**    Try to convert pRec to an integer representation or a
+**    floating-point representation if an integer representation
+**    is not possible.  Note that the integer representation is
+**    always preferred, even if the affinity is REAL, because
+**    an integer representation is more space efficient on disk.
+**
+** SQLITE_AFF_FLEXNUM:
+**    If the value is text, then try to convert it into a number of
+**    some kind (integer or real) but do not make any other changes.
+**
+** SQLITE_AFF_TEXT:
+**    Convert pRec to a text representation.
+**
+** SQLITE_AFF_BLOB:
+** SQLITE_AFF_NONE:
+**    No-op.  pRec is unchanged.
+*/
+static void applyAffinity(
+  Mem *pRec,          /* The value to apply affinity to */
+  char affinity,      /* The affinity to be applied */
+  u8 enc              /* Use this text encoding */
+){
+  if( affinity>=SQLITE_AFF_NUMERIC ){
+    assert( affinity==SQLITE_AFF_INTEGER || affinity==SQLITE_AFF_REAL
+             || affinity==SQLITE_AFF_NUMERIC || affinity==SQLITE_AFF_FLEXNUM );
+    if( (pRec->flags & MEM_Int)==0 ){ /*OPTIMIZATION-IF-FALSE*/
+      if( (pRec->flags & (MEM_Real|MEM_IntReal))==0 ){
+        if( pRec->flags & MEM_Str ) applyNumericAffinity(pRec,1);
+      }else if( affinity<=SQLITE_AFF_REAL ){
+        sqlite3VdbeIntegerAffinity(pRec);
+      }
+    }
+  }else if( affinity==SQLITE_AFF_TEXT ){
+    /* Only attempt the conversion to TEXT if there is an integer or real
+    ** representation (blob and NULL do not get converted) but no string
+    ** representation.  It would be harmless to repeat the conversion if
+    ** there is already a string rep, but it is pointless to waste those
+    ** CPU cycles. */
+    if( 0==(pRec->flags&MEM_Str) ){ /*OPTIMIZATION-IF-FALSE*/
+      if( (pRec->flags&(MEM_Real|MEM_Int|MEM_IntReal)) ){
+        testcase( pRec->flags & MEM_Int );
+        testcase( pRec->flags & MEM_Real );
+        testcase( pRec->flags & MEM_IntReal );
+        sqlite3VdbeMemStringify(pRec, enc, 1);
+      }
+    }
+    pRec->flags &= ~(MEM_Real|MEM_Int|MEM_IntReal);
+  }
+}
+
+/*
+** Try to convert the type of a function argument or a result column
+** into a numeric representation.  Use either INTEGER or REAL whichever
+** is appropriate.  But only do the conversion if it is possible without
+** loss of information and return the revised type of the argument.
+*/
+SQLITE_API int sqlite3_value_numeric_type(sqlite3_value *pVal){
+  int eType = sqlite3_value_type(pVal);
+  if( eType==SQLITE_TEXT ){
+    Mem *pMem = (Mem*)pVal;
+    applyNumericAffinity(pMem, 0);
+    eType = sqlite3_value_type(pVal);
+  }
+  return eType;
+}
+
+/*
+** Exported version of applyAffinity(). This one works on sqlite3_value*,
+** not the internal Mem* type.
+*/
+SQLITE_PRIVATE void sqlite3ValueApplyAffinity(
+  sqlite3_value *pVal,
+  u8 affinity,
+  u8 enc
+){
+  applyAffinity((Mem *)pVal, affinity, enc);
+}
+
+/*
+** pMem currently only holds a string type (or maybe a BLOB that we can
+** interpret as a string if we want to).  Compute its corresponding
+** numeric type, if has one.  Set the pMem->u.r and pMem->u.i fields
+** accordingly.
+*/
+static u16 SQLITE_NOINLINE computeNumericType(Mem *pMem){
+  int rc;
+  sqlite3_int64 ix;
+  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal))==0 );
+  assert( (pMem->flags & (MEM_Str|MEM_Blob))!=0 );
+  if( ExpandBlob(pMem) ){
+    pMem->u.i = 0;
+    return MEM_Int;
+  }
+  rc = sqlite3AtoF(pMem->z, &pMem->u.r, pMem->n, pMem->enc);
+  if( rc<=0 ){
+    if( rc==0 && sqlite3Atoi64(pMem->z, &ix, pMem->n, pMem->enc)<=1 ){
+      pMem->u.i = ix;
+      return MEM_Int;
+    }else{
+      return MEM_Real;
+    }
+  }else if( rc==1 && sqlite3Atoi64(pMem->z, &ix, pMem->n, pMem->enc)==0 ){
+    pMem->u.i = ix;
+    return MEM_Int;
+  }
+  return MEM_Real;
+}
+
+/*
+** Return the numeric type for pMem, either MEM_Int or MEM_Real or both or
+** none.
+**
+** Unlike applyNumericAffinity(), this routine does not modify pMem->flags.
+** But it does set pMem->u.r and pMem->u.i appropriately.
+*/
+static u16 numericType(Mem *pMem){
+  assert( (pMem->flags & MEM_Null)==0
+       || pMem->db==0 || pMem->db->mallocFailed );
+  if( pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null) ){
+    testcase( pMem->flags & MEM_Int );
+    testcase( pMem->flags & MEM_Real );
+    testcase( pMem->flags & MEM_IntReal );
+    return pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null);
+  }
+  assert( pMem->flags & (MEM_Str|MEM_Blob) );
+  testcase( pMem->flags & MEM_Str );
+  testcase( pMem->flags & MEM_Blob );
+  return computeNumericType(pMem);
+  return 0;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Write a nice string representation of the contents of cell pMem
+** into buffer zBuf, length nBuf.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemPrettyPrint(Mem *pMem, StrAccum *pStr){
+  int f = pMem->flags;
+  static const char *const encnames[] = {"(X)", "(8)", "(16LE)", "(16BE)"};
+  if( f&MEM_Blob ){
+    int i;
+    char c;
+    if( f & MEM_Dyn ){
+      c = 'z';
+      assert( (f & (MEM_Static|MEM_Ephem))==0 );
+    }else if( f & MEM_Static ){
+      c = 't';
+      assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
+    }else if( f & MEM_Ephem ){
+      c = 'e';
+      assert( (f & (MEM_Static|MEM_Dyn))==0 );
+    }else{
+      c = 's';
+    }
+    sqlite3_str_appendf(pStr, "%cx[", c);
+    for(i=0; i<25 && i<pMem->n; i++){
+      sqlite3_str_appendf(pStr, "%02X", ((int)pMem->z[i] & 0xFF));
+    }
+    sqlite3_str_appendf(pStr, "|");
+    for(i=0; i<25 && i<pMem->n; i++){
+      char z = pMem->z[i];
+      sqlite3_str_appendchar(pStr, 1, (z<32||z>126)?'.':z);
+    }
+    sqlite3_str_appendf(pStr,"]");
+    if( f & MEM_Zero ){
+      sqlite3_str_appendf(pStr, "+%dz",pMem->u.nZero);
+    }
+  }else if( f & MEM_Str ){
+    int j;
+    u8 c;
+    if( f & MEM_Dyn ){
+      c = 'z';
+      assert( (f & (MEM_Static|MEM_Ephem))==0 );
+    }else if( f & MEM_Static ){
+      c = 't';
+      assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
+    }else if( f & MEM_Ephem ){
+      c = 'e';
+      assert( (f & (MEM_Static|MEM_Dyn))==0 );
+    }else{
+      c = 's';
+    }
+    sqlite3_str_appendf(pStr, " %c%d[", c, pMem->n);
+    for(j=0; j<25 && j<pMem->n; j++){
+      c = pMem->z[j];
+      sqlite3_str_appendchar(pStr, 1, (c>=0x20&&c<=0x7f) ? c : '.');
+    }
+    sqlite3_str_appendf(pStr, "]%s", encnames[pMem->enc]);
+    if( f & MEM_Term ){
+      sqlite3_str_appendf(pStr, "(0-term)");
+    }
+  }
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Print the value of a register for tracing purposes:
+*/
+static void memTracePrint(Mem *p){
+  if( p->flags & MEM_Undefined ){
+    printf(" undefined");
+  }else if( p->flags & MEM_Null ){
+    printf(p->flags & MEM_Zero ? " NULL-nochng" : " NULL");
+  }else if( (p->flags & (MEM_Int|MEM_Str))==(MEM_Int|MEM_Str) ){
+    printf(" si:%lld", p->u.i);
+  }else if( (p->flags & (MEM_IntReal))!=0 ){
+    printf(" ir:%lld", p->u.i);
+  }else if( p->flags & MEM_Int ){
+    printf(" i:%lld", p->u.i);
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  }else if( p->flags & MEM_Real ){
+    printf(" r:%.17g", p->u.r);
+#endif
+  }else if( sqlite3VdbeMemIsRowSet(p) ){
+    printf(" (rowset)");
+  }else{
+    StrAccum acc;
+    char zBuf[1000];
+    sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+    sqlite3VdbeMemPrettyPrint(p, &acc);
+    printf(" %s", sqlite3StrAccumFinish(&acc));
+  }
+  if( p->flags & MEM_Subtype ) printf(" subtype=0x%02x", p->eSubtype);
+}
+static void registerTrace(int iReg, Mem *p){
+  printf("R[%d] = ", iReg);
+  memTracePrint(p);
+  if( p->pScopyFrom ){
+    assert( p->pScopyFrom->bScopy );
+    printf(" <== R[%d]", (int)(p->pScopyFrom - &p[-iReg]));
+  }
+  printf("\n");
+  sqlite3VdbeCheckMemInvariants(p);
+}
+/**/ void sqlite3PrintMem(Mem *pMem){
+  memTracePrint(pMem);
+  printf("\n");
+  fflush(stdout);
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Show the values of all registers in the virtual machine.  Used for
+** interactive debugging.
+*/
+SQLITE_PRIVATE void sqlite3VdbeRegisterDump(Vdbe *v){
+  int i;
+  for(i=1; i<v->nMem; i++) registerTrace(i, v->aMem+i);
+}
+#endif /* SQLITE_DEBUG */
+
+
+#ifdef SQLITE_DEBUG
+#  define REGISTER_TRACE(R,M) if(db->flags&SQLITE_VdbeTrace)registerTrace(R,M)
+#else
+#  define REGISTER_TRACE(R,M)
+#endif
+
+#ifndef NDEBUG
+/*
+** This function is only called from within an assert() expression. It
+** checks that the sqlite3.nTransaction variable is correctly set to
+** the number of non-transaction savepoints currently in the
+** linked list starting at sqlite3.pSavepoint.
+**
+** Usage:
+**
+**     assert( checkSavepointCount(db) );
+*/
+static int checkSavepointCount(sqlite3 *db){
+  int n = 0;
+  Savepoint *p;
+  for(p=db->pSavepoint; p; p=p->pNext) n++;
+  assert( n==(db->nSavepoint + db->isTransactionSavepoint) );
+  return 1;
+}
+#endif
+
+/*
+** Return the register of pOp->p2 after first preparing it to be
+** overwritten with an integer value.
+*/
+static SQLITE_NOINLINE Mem *out2PrereleaseWithClear(Mem *pOut){
+  sqlite3VdbeMemSetNull(pOut);
+  pOut->flags = MEM_Int;
+  return pOut;
+}
+static Mem *out2Prerelease(Vdbe *p, VdbeOp *pOp){
+  Mem *pOut;
+  assert( pOp->p2>0 );
+  assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
+  pOut = &p->aMem[pOp->p2];
+  memAboutToChange(p, pOut);
+  if( VdbeMemDynamic(pOut) ){ /*OPTIMIZATION-IF-FALSE*/
+    return out2PrereleaseWithClear(pOut);
+  }else{
+    pOut->flags = MEM_Int;
+    return pOut;
+  }
+}
+
+/*
+** Compute a bloom filter hash using pOp->p4.i registers from aMem[] beginning
+** with pOp->p3.  Return the hash.
+*/
+static u64 filterHash(const Mem *aMem, const Op *pOp){
+  int i, mx;
+  u64 h = 0;
+
+  assert( pOp->p4type==P4_INT32 );
+  for(i=pOp->p3, mx=i+pOp->p4.i; i<mx; i++){
+    const Mem *p = &aMem[i];
+    if( p->flags & (MEM_Int|MEM_IntReal) ){
+      h += p->u.i;
+    }else if( p->flags & MEM_Real ){
+      h += sqlite3VdbeIntValue(p);
+    }else if( p->flags & (MEM_Str|MEM_Blob) ){
+      /* All strings have the same hash and all blobs have the same hash,
+      ** though, at least, those hashes are different from each other and
+      ** from NULL. */
+      h += 4093 + (p->flags & (MEM_Str|MEM_Blob));
+    }
+  }
+  return h;
+}
+
+
+/*
+** For OP_Column, factor out the case where content is loaded from
+** overflow pages, so that the code to implement this case is separate
+** the common case where all content fits on the page.  Factoring out
+** the code reduces register pressure and helps the common case
+** to run faster.
+*/
+static SQLITE_NOINLINE int vdbeColumnFromOverflow(
+  VdbeCursor *pC,       /* The BTree cursor from which we are reading */
+  int iCol,             /* The column to read */
+  int t,                /* The serial-type code for the column value */
+  i64 iOffset,          /* Offset to the start of the content value */
+  u32 cacheStatus,      /* Current Vdbe.cacheCtr value */
+  u32 colCacheCtr,      /* Current value of the column cache counter */
+  Mem *pDest            /* Store the value into this register. */
+){
+  int rc;
+  sqlite3 *db = pDest->db;
+  int encoding = pDest->enc;
+  int len = sqlite3VdbeSerialTypeLen(t);
+  assert( pC->eCurType==CURTYPE_BTREE );
+  if( len>db->aLimit[SQLITE_LIMIT_LENGTH] ) return SQLITE_TOOBIG;
+  if( len > 4000 && pC->pKeyInfo==0 ){
+    /* Cache large column values that are on overflow pages using
+    ** an RCStr (reference counted string) so that if they are reloaded,
+    ** that do not have to be copied a second time.  The overhead of
+    ** creating and managing the cache is such that this is only
+    ** profitable for larger TEXT and BLOB values.
+    **
+    ** Only do this on table-btrees so that writes to index-btrees do not
+    ** need to clear the cache.  This buys performance in the common case
+    ** in exchange for generality.
+    */
+    VdbeTxtBlbCache *pCache;
+    char *pBuf;
+    if( pC->colCache==0 ){
+      pC->pCache = sqlite3DbMallocZero(db, sizeof(VdbeTxtBlbCache) );
+      if( pC->pCache==0 ) return SQLITE_NOMEM;
+      pC->colCache = 1;
+    }
+    pCache = pC->pCache;
+    if( pCache->pCValue==0
+     || pCache->iCol!=iCol
+     || pCache->cacheStatus!=cacheStatus
+     || pCache->colCacheCtr!=colCacheCtr
+     || pCache->iOffset!=sqlite3BtreeOffset(pC->uc.pCursor)
+    ){
+      if( pCache->pCValue ) sqlite3RCStrUnref(pCache->pCValue);
+      pBuf = pCache->pCValue = sqlite3RCStrNew( len+3 );
+      if( pBuf==0 ) return SQLITE_NOMEM;
+      rc = sqlite3BtreePayload(pC->uc.pCursor, iOffset, len, pBuf);
+      if( rc ) return rc;
+      pBuf[len] = 0;
+      pBuf[len+1] = 0;
+      pBuf[len+2] = 0;
+      pCache->iCol = iCol;
+      pCache->cacheStatus = cacheStatus;
+      pCache->colCacheCtr = colCacheCtr;
+      pCache->iOffset = sqlite3BtreeOffset(pC->uc.pCursor);
+    }else{
+      pBuf = pCache->pCValue;
+    }
+    assert( t>=12 );
+    sqlite3RCStrRef(pBuf);
+    if( t&1 ){
+      rc = sqlite3VdbeMemSetStr(pDest, pBuf, len, encoding,
+                                sqlite3RCStrUnref);
+      pDest->flags |= MEM_Term;
+    }else{
+      rc = sqlite3VdbeMemSetStr(pDest, pBuf, len, 0,
+                                sqlite3RCStrUnref);
+    }
+  }else{
+    rc = sqlite3VdbeMemFromBtree(pC->uc.pCursor, iOffset, len, pDest);
+    if( rc ) return rc;
+    sqlite3VdbeSerialGet((const u8*)pDest->z, t, pDest);
+    if( (t&1)!=0 && encoding==SQLITE_UTF8 ){
+      pDest->z[len] = 0;
+      pDest->flags |= MEM_Term;
+    }
+  }
+  pDest->flags &= ~MEM_Ephem;
+  return rc;
+}
+
+
+/*
+** Return the symbolic name for the data type of a pMem
+*/
+static const char *vdbeMemTypeName(Mem *pMem){
+  static const char *azTypes[] = {
+      /* SQLITE_INTEGER */ "INT",
+      /* SQLITE_FLOAT   */ "REAL",
+      /* SQLITE_TEXT    */ "TEXT",
+      /* SQLITE_BLOB    */ "BLOB",
+      /* SQLITE_NULL    */ "NULL"
+  };
+  return azTypes[sqlite3_value_type(pMem)-1];
+}
+
+/*
+** Execute as much of a VDBE program as we can.
+** This is the core of sqlite3_step().
+*/
+SQLITE_PRIVATE int sqlite3VdbeExec(
+  Vdbe *p                    /* The VDBE */
+){
+  Op *aOp = p->aOp;          /* Copy of p->aOp */
+  Op *pOp = aOp;             /* Current operation */
+#ifdef SQLITE_DEBUG
+  Op *pOrigOp;               /* Value of pOp at the top of the loop */
+  int nExtraDelete = 0;      /* Verifies FORDELETE and AUXDELETE flags */
+  u8 iCompareIsInit = 0;     /* iCompare is initialized */
+#endif
+  int rc = SQLITE_OK;        /* Value to return */
+  sqlite3 *db = p->db;       /* The database */
+  u8 resetSchemaOnFault = 0; /* Reset schema after an error if positive */
+  u8 encoding = ENC(db);     /* The database encoding */
+  int iCompare = 0;          /* Result of last comparison */
+  u64 nVmStep = 0;           /* Number of virtual machine steps */
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  u64 nProgressLimit;        /* Invoke xProgress() when nVmStep reaches this */
+#endif
+  Mem *aMem = p->aMem;       /* Copy of p->aMem */
+  Mem *pIn1 = 0;             /* 1st input operand */
+  Mem *pIn2 = 0;             /* 2nd input operand */
+  Mem *pIn3 = 0;             /* 3rd input operand */
+  Mem *pOut = 0;             /* Output operand */
+  u32 colCacheCtr = 0;       /* Column cache counter */
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
+  u64 *pnCycle = 0;
+  int bStmtScanStatus = IS_STMT_SCANSTATUS(db)!=0;
+#endif
+  /*** INSERT STACK UNION HERE ***/
+
+  assert( p->eVdbeState==VDBE_RUN_STATE );  /* sqlite3_step() verifies this */
+  if( DbMaskNonZero(p->lockMask) ){
+    sqlite3VdbeEnter(p);
+  }
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  if( db->xProgress ){
+    u32 iPrior = p->aCounter[SQLITE_STMTSTATUS_VM_STEP];
+    assert( 0 < db->nProgressOps );
+    nProgressLimit = db->nProgressOps - (iPrior % db->nProgressOps);
+  }else{
+    nProgressLimit = LARGEST_UINT64;
+  }
+#endif
+  if( p->rc==SQLITE_NOMEM ){
+    /* This happens if a malloc() inside a call to sqlite3_column_text() or
+    ** sqlite3_column_text16() failed.  */
+    goto no_mem;
+  }
+  assert( p->rc==SQLITE_OK || (p->rc&0xff)==SQLITE_BUSY );
+  testcase( p->rc!=SQLITE_OK );
+  p->rc = SQLITE_OK;
+  assert( p->bIsReader || p->readOnly!=0 );
+  p->iCurrentTime = 0;
+  assert( p->explain==0 );
+  db->busyHandler.nBusy = 0;
+  if( AtomicLoad(&db->u1.isInterrupted) ) goto abort_due_to_interrupt;
+  sqlite3VdbeIOTraceSql(p);
+#ifdef SQLITE_DEBUG
+  sqlite3BeginBenignMalloc();
+  if( p->pc==0
+   && (p->db->flags & (SQLITE_VdbeListing|SQLITE_VdbeEQP|SQLITE_VdbeTrace))!=0
+  ){
+    int i;
+    int once = 1;
+    sqlite3VdbePrintSql(p);
+    if( p->db->flags & SQLITE_VdbeListing ){
+      printf("VDBE Program Listing:\n");
+      for(i=0; i<p->nOp; i++){
+        sqlite3VdbePrintOp(stdout, i, &aOp[i]);
+      }
+    }
+    if( p->db->flags & SQLITE_VdbeEQP ){
+      for(i=0; i<p->nOp; i++){
+        if( aOp[i].opcode==OP_Explain ){
+          if( once ) printf("VDBE Query Plan:\n");
+          printf("%s\n", aOp[i].p4.z);
+          once = 0;
+        }
+      }
+    }
+    if( p->db->flags & SQLITE_VdbeTrace )  printf("VDBE Trace:\n");
+  }
+  sqlite3EndBenignMalloc();
+#endif
+  for(pOp=&aOp[p->pc]; 1; pOp++){
+    /* Errors are detected by individual opcodes, with an immediate
+    ** jumps to abort_due_to_error. */
+    assert( rc==SQLITE_OK );
+
+    assert( pOp>=aOp && pOp<&aOp[p->nOp]);
+    nVmStep++;
+
+#if defined(VDBE_PROFILE)
+    pOp->nExec++;
+    pnCycle = &pOp->nCycle;
+    if( sqlite3NProfileCnt==0 ) *pnCycle -= sqlite3Hwtime();
+#elif defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+    if( bStmtScanStatus ){
+      pOp->nExec++;
+      pnCycle = &pOp->nCycle;
+      *pnCycle -= sqlite3Hwtime();
+    }
+#endif
+
+    /* Only allow tracing if SQLITE_DEBUG is defined.
+    */
+#ifdef SQLITE_DEBUG
+    if( db->flags & SQLITE_VdbeTrace ){
+      sqlite3VdbePrintOp(stdout, (int)(pOp - aOp), pOp);
+      test_trace_breakpoint((int)(pOp - aOp),pOp,p);
+    }
+#endif
+
+
+    /* Check to see if we need to simulate an interrupt.  This only happens
+    ** if we have a special test build.
+    */
+#ifdef SQLITE_TEST
+    if( sqlite3_interrupt_count>0 ){
+      sqlite3_interrupt_count--;
+      if( sqlite3_interrupt_count==0 ){
+        sqlite3_interrupt(db);
+      }
+    }
+#endif
+
+    /* Sanity checking on other operands */
+#ifdef SQLITE_DEBUG
+    {
+      u8 opProperty = sqlite3OpcodeProperty[pOp->opcode];
+      if( (opProperty & OPFLG_IN1)!=0 ){
+        assert( pOp->p1>0 );
+        assert( pOp->p1<=(p->nMem+1 - p->nCursor) );
+        assert( memIsValid(&aMem[pOp->p1]) );
+        assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p1]) );
+        REGISTER_TRACE(pOp->p1, &aMem[pOp->p1]);
+      }
+      if( (opProperty & OPFLG_IN2)!=0 ){
+        assert( pOp->p2>0 );
+        assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
+        assert( memIsValid(&aMem[pOp->p2]) );
+        assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p2]) );
+        REGISTER_TRACE(pOp->p2, &aMem[pOp->p2]);
+      }
+      if( (opProperty & OPFLG_IN3)!=0 ){
+        assert( pOp->p3>0 );
+        assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+        assert( memIsValid(&aMem[pOp->p3]) );
+        assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p3]) );
+        REGISTER_TRACE(pOp->p3, &aMem[pOp->p3]);
+      }
+      if( (opProperty & OPFLG_OUT2)!=0 ){
+        assert( pOp->p2>0 );
+        assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
+        memAboutToChange(p, &aMem[pOp->p2]);
+      }
+      if( (opProperty & OPFLG_OUT3)!=0 ){
+        assert( pOp->p3>0 );
+        assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+        memAboutToChange(p, &aMem[pOp->p3]);
+      }
+    }
+#endif
+#ifdef SQLITE_DEBUG
+    pOrigOp = pOp;
+#endif
+
+    switch( pOp->opcode ){
+
+/*****************************************************************************
+** What follows is a massive switch statement where each case implements a
+** separate instruction in the virtual machine.  If we follow the usual
+** indentation conventions, each case should be indented by 6 spaces.  But
+** that is a lot of wasted space on the left margin.  So the code within
+** the switch statement will break with convention and be flush-left. Another
+** big comment (similar to this one) will mark the point in the code where
+** we transition back to normal indentation.
+**
+** The formatting of each case is important.  The makefile for SQLite
+** generates two C files "opcodes.h" and "opcodes.c" by scanning this
+** file looking for lines that begin with "case OP_".  The opcodes.h files
+** will be filled with #defines that give unique integer values to each
+** opcode and the opcodes.c file is filled with an array of strings where
+** each string is the symbolic name for the corresponding opcode.  If the
+** case statement is followed by a comment of the form "/# same as ... #/"
+** that comment is used to determine the particular value of the opcode.
+**
+** Other keywords in the comment that follows each case are used to
+** construct the OPFLG_INITIALIZER value that initializes opcodeProperty[].
+** Keywords include: in1, in2, in3, out2, out3.  See
+** the mkopcodeh.awk script for additional information.
+**
+** Documentation about VDBE opcodes is generated by scanning this file
+** for lines of that contain "Opcode:".  That line and all subsequent
+** comment lines are used in the generation of the opcode.html documentation
+** file.
+**
+** SUMMARY:
+**
+**     Formatting is important to scripts that scan this file.
+**     Do not deviate from the formatting style currently in use.
+**
+*****************************************************************************/
+
+/* Opcode:  Goto * P2 * * *
+**
+** An unconditional jump to address P2.
+** The next instruction executed will be
+** the one at index P2 from the beginning of
+** the program.
+**
+** The P1 parameter is not actually used by this opcode.  However, it
+** is sometimes set to 1 instead of 0 as a hint to the command-line shell
+** that this Goto is the bottom of a loop and that the lines from P2 down
+** to the current line should be indented for EXPLAIN output.
+*/
+case OP_Goto: {             /* jump */
+
+#ifdef SQLITE_DEBUG
+  /* In debugging mode, when the p5 flags is set on an OP_Goto, that
+  ** means we should really jump back to the preceding OP_ReleaseReg
+  ** instruction. */
+  if( pOp->p5 ){
+    assert( pOp->p2 < (int)(pOp - aOp) );
+    assert( pOp->p2 > 1 );
+    pOp = &aOp[pOp->p2 - 2];
+    assert( pOp[1].opcode==OP_ReleaseReg );
+    goto check_for_interrupt;
+  }
+#endif
+
+jump_to_p2_and_check_for_interrupt:
+  pOp = &aOp[pOp->p2 - 1];
+
+  /* Opcodes that are used as the bottom of a loop (OP_Next, OP_Prev,
+  ** OP_VNext, or OP_SorterNext) all jump here upon
+  ** completion.  Check to see if sqlite3_interrupt() has been called
+  ** or if the progress callback needs to be invoked.
+  **
+  ** This code uses unstructured "goto" statements and does not look clean.
+  ** But that is not due to sloppy coding habits. The code is written this
+  ** way for performance, to avoid having to run the interrupt and progress
+  ** checks on every opcode.  This helps sqlite3_step() to run about 1.5%
+  ** faster according to "valgrind --tool=cachegrind" */
+check_for_interrupt:
+  if( AtomicLoad(&db->u1.isInterrupted) ) goto abort_due_to_interrupt;
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  /* Call the progress callback if it is configured and the required number
+  ** of VDBE ops have been executed (either since this invocation of
+  ** sqlite3VdbeExec() or since last time the progress callback was called).
+  ** If the progress callback returns non-zero, exit the virtual machine with
+  ** a return code SQLITE_ABORT.
+  */
+  while( nVmStep>=nProgressLimit && db->xProgress!=0 ){
+    assert( db->nProgressOps!=0 );
+    nProgressLimit += db->nProgressOps;
+    if( db->xProgress(db->pProgressArg) ){
+      nProgressLimit = LARGEST_UINT64;
+      rc = SQLITE_INTERRUPT;
+      goto abort_due_to_error;
+    }
+  }
+#endif
+
+  break;
+}
+
+/* Opcode:  Gosub P1 P2 * * *
+**
+** Write the current address onto register P1
+** and then jump to address P2.
+*/
+case OP_Gosub: {            /* jump */
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  pIn1 = &aMem[pOp->p1];
+  assert( VdbeMemDynamic(pIn1)==0 );
+  memAboutToChange(p, pIn1);
+  pIn1->flags = MEM_Int;
+  pIn1->u.i = (int)(pOp-aOp);
+  REGISTER_TRACE(pOp->p1, pIn1);
+  goto jump_to_p2_and_check_for_interrupt;
+}
+
+/* Opcode:  Return P1 P2 P3 * *
+**
+** Jump to the address stored in register P1.  If P1 is a return address
+** register, then this accomplishes a return from a subroutine.
+**
+** If P3 is 1, then the jump is only taken if register P1 holds an integer
+** values, otherwise execution falls through to the next opcode, and the
+** OP_Return becomes a no-op. If P3 is 0, then register P1 must hold an
+** integer or else an assert() is raised.  P3 should be set to 1 when
+** this opcode is used in combination with OP_BeginSubrtn, and set to 0
+** otherwise.
+**
+** The value in register P1 is unchanged by this opcode.
+**
+** P2 is not used by the byte-code engine.  However, if P2 is positive
+** and also less than the current address, then the "EXPLAIN" output
+** formatter in the CLI will indent all opcodes from the P2 opcode up
+** to be not including the current Return.   P2 should be the first opcode
+** in the subroutine from which this opcode is returning.  Thus the P2
+** value is a byte-code indentation hint.  See tag-20220407a in
+** wherecode.c and shell.c.
+*/
+case OP_Return: {           /* in1 */
+  pIn1 = &aMem[pOp->p1];
+  if( pIn1->flags & MEM_Int ){
+    if( pOp->p3 ){ VdbeBranchTaken(1, 2); }
+    pOp = &aOp[pIn1->u.i];
+  }else if( ALWAYS(pOp->p3) ){
+    VdbeBranchTaken(0, 2);
+  }
+  break;
+}
+
+/* Opcode: InitCoroutine P1 P2 P3 * *
+**
+** Set up register P1 so that it will Yield to the coroutine
+** located at address P3.
+**
+** If P2!=0 then the coroutine implementation immediately follows
+** this opcode.  So jump over the coroutine implementation to
+** address P2.
+**
+** See also: EndCoroutine
+*/
+case OP_InitCoroutine: {     /* jump0 */
+  assert( pOp->p1>0 &&  pOp->p1<=(p->nMem+1 - p->nCursor) );
+  assert( pOp->p2>=0 && pOp->p2<p->nOp );
+  assert( pOp->p3>=0 && pOp->p3<p->nOp );
+  pOut = &aMem[pOp->p1];
+  assert( !VdbeMemDynamic(pOut) );
+  pOut->u.i = pOp->p3 - 1;
+  pOut->flags = MEM_Int;
+  if( pOp->p2==0 ) break;
+
+  /* Most jump operations do a goto to this spot in order to update
+  ** the pOp pointer. */
+jump_to_p2:
+  assert( pOp->p2>0 );       /* There are never any jumps to instruction 0 */
+  assert( pOp->p2<p->nOp );  /* Jumps must be in range */
+  pOp = &aOp[pOp->p2 - 1];
+  break;
+}
+
+/* Opcode:  EndCoroutine P1 * * * *
+**
+** The instruction at the address in register P1 is a Yield.
+** Jump to the P2 parameter of that Yield.
+** After the jump, the value register P1 is left with a value
+** such that subsequent OP_Yields go back to the this same
+** OP_EndCoroutine instruction.
+**
+** See also: InitCoroutine
+*/
+case OP_EndCoroutine: {           /* in1 */
+  VdbeOp *pCaller;
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags==MEM_Int );
+  assert( pIn1->u.i>=0 && pIn1->u.i<p->nOp );
+  pCaller = &aOp[pIn1->u.i];
+  assert( pCaller->opcode==OP_Yield );
+  assert( pCaller->p2>=0 && pCaller->p2<p->nOp );
+  pIn1->u.i = (int)(pOp - p->aOp) - 1;
+  pOp = &aOp[pCaller->p2 - 1];
+  break;
+}
+
+/* Opcode:  Yield P1 P2 * * *
+**
+** Swap the program counter with the value in register P1.  This
+** has the effect of yielding to a coroutine.
+**
+** If the coroutine that is launched by this instruction ends with
+** Yield or Return then continue to the next instruction.  But if
+** the coroutine launched by this instruction ends with
+** EndCoroutine, then jump to P2 rather than continuing with the
+** next instruction.
+**
+** See also: InitCoroutine
+*/
+case OP_Yield: {            /* in1, jump0 */
+  int pcDest;
+  pIn1 = &aMem[pOp->p1];
+  assert( VdbeMemDynamic(pIn1)==0 );
+  pIn1->flags = MEM_Int;
+  pcDest = (int)pIn1->u.i;
+  pIn1->u.i = (int)(pOp - aOp);
+  REGISTER_TRACE(pOp->p1, pIn1);
+  pOp = &aOp[pcDest];
+  break;
+}
+
+/* Opcode:  HaltIfNull  P1 P2 P3 P4 P5
+** Synopsis: if r[P3]=null halt
+**
+** Check the value in register P3.  If it is NULL then Halt using
+** parameter P1, P2, and P4 as if this were a Halt instruction.  If the
+** value in register P3 is not NULL, then this routine is a no-op.
+** The P5 parameter should be 1.
+*/
+case OP_HaltIfNull: {      /* in3 */
+  pIn3 = &aMem[pOp->p3];
+#ifdef SQLITE_DEBUG
+  if( pOp->p2==OE_Abort ){ sqlite3VdbeAssertAbortable(p); }
+#endif
+  if( (pIn3->flags & MEM_Null)==0 ) break;
+  /* Fall through into OP_Halt */
+  /* no break */ deliberate_fall_through
+}
+
+/* Opcode:  Halt P1 P2 P3 P4 P5
+**
+** Exit immediately.  All open cursors, etc are closed
+** automatically.
+**
+** P1 is the result code returned by sqlite3_exec(), sqlite3_reset(),
+** or sqlite3_finalize().  For a normal halt, this should be SQLITE_OK (0).
+** For errors, it can be some other value.  If P1!=0 then P2 will determine
+** whether or not to rollback the current transaction.  Do not rollback
+** if P2==OE_Fail. Do the rollback if P2==OE_Rollback.  If P2==OE_Abort,
+** then back out all changes that have occurred during this execution of the
+** VDBE, but do not rollback the transaction.
+**
+** If P3 is not zero and P4 is NULL, then P3 is a register that holds the
+** text of an error message.
+**
+** If P3 is zero and P4 is not null then the error message string is held
+** in P4.
+**
+** P5 is a value between 1 and 4, inclusive, then the P4 error message
+** string is modified as follows:
+**
+**    1:  NOT NULL constraint failed: P4
+**    2:  UNIQUE constraint failed: P4
+**    3:  CHECK constraint failed: P4
+**    4:  FOREIGN KEY constraint failed: P4
+**
+** If P3 is zero and P5 is not zero and P4 is NULL, then everything after
+** the ":" is omitted.
+**
+** There is an implied "Halt 0 0 0" instruction inserted at the very end of
+** every program.  So a jump past the last instruction of the program
+** is the same as executing Halt.
+*/
+case OP_Halt: {
+  VdbeFrame *pFrame;
+  int pcx;
+
+#ifdef SQLITE_DEBUG
+  if( pOp->p2==OE_Abort ){ sqlite3VdbeAssertAbortable(p); }
+#endif
+  assert( pOp->p4type==P4_NOTUSED
+       || pOp->p4type==P4_STATIC
+       || pOp->p4type==P4_DYNAMIC );
+
+  /* A deliberately coded "OP_Halt SQLITE_INTERNAL * * * *" opcode indicates
+  ** something is wrong with the code generator.  Raise an assertion in order
+  ** to bring this to the attention of fuzzers and other testing tools. */
+  assert( pOp->p1!=SQLITE_INTERNAL );
+
+  if( p->pFrame && pOp->p1==SQLITE_OK ){
+    /* Halt the sub-program. Return control to the parent frame. */
+    pFrame = p->pFrame;
+    p->pFrame = pFrame->pParent;
+    p->nFrame--;
+    sqlite3VdbeSetChanges(db, p->nChange);
+    pcx = sqlite3VdbeFrameRestore(pFrame);
+    if( pOp->p2==OE_Ignore ){
+      /* Instruction pcx is the OP_Program that invoked the sub-program
+      ** currently being halted. If the p2 instruction of this OP_Halt
+      ** instruction is set to OE_Ignore, then the sub-program is throwing
+      ** an IGNORE exception. In this case jump to the address specified
+      ** as the p2 of the calling OP_Program.  */
+      pcx = p->aOp[pcx].p2-1;
+    }
+    aOp = p->aOp;
+    aMem = p->aMem;
+    pOp = &aOp[pcx];
+    break;
+  }
+  p->rc = pOp->p1;
+  p->errorAction = (u8)pOp->p2;
+  assert( pOp->p5<=4 );
+  if( p->rc ){
+    if( pOp->p3>0 && pOp->p4type==P4_NOTUSED ){
+      const char *zErr;
+      assert( pOp->p3<=(p->nMem + 1 - p->nCursor) );
+      zErr = sqlite3ValueText(&aMem[pOp->p3], SQLITE_UTF8);
+      sqlite3VdbeError(p, "%s", zErr);
+    }else if( pOp->p5 ){
+      static const char * const azType[] = { "NOT NULL", "UNIQUE", "CHECK",
+                                             "FOREIGN KEY" };
+      testcase( pOp->p5==1 );
+      testcase( pOp->p5==2 );
+      testcase( pOp->p5==3 );
+      testcase( pOp->p5==4 );
+      sqlite3VdbeError(p, "%s constraint failed", azType[pOp->p5-1]);
+      if( pOp->p4.z ){
+        p->zErrMsg = sqlite3MPrintf(db, "%z: %s", p->zErrMsg, pOp->p4.z);
+      }
+    }else{
+      sqlite3VdbeError(p, "%s", pOp->p4.z);
+    }
+    pcx = (int)(pOp - aOp);
+    sqlite3_log(pOp->p1, "abort at %d in [%s]: %s", pcx, p->zSql, p->zErrMsg);
+  }
+  rc = sqlite3VdbeHalt(p);
+  assert( rc==SQLITE_BUSY || rc==SQLITE_OK || rc==SQLITE_ERROR );
+  if( rc==SQLITE_BUSY ){
+    p->rc = SQLITE_BUSY;
+  }else{
+    assert( rc==SQLITE_OK || (p->rc&0xff)==SQLITE_CONSTRAINT );
+    assert( rc==SQLITE_OK || db->nDeferredCons>0 || db->nDeferredImmCons>0 );
+    rc = p->rc ? SQLITE_ERROR : SQLITE_DONE;
+  }
+  goto vdbe_return;
+}
+
+/* Opcode: Integer P1 P2 * * *
+** Synopsis: r[P2]=P1
+**
+** The 32-bit integer value P1 is written into register P2.
+*/
+case OP_Integer: {         /* out2 */
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = pOp->p1;
+  break;
+}
+
+/* Opcode: Int64 * P2 * P4 *
+** Synopsis: r[P2]=P4
+**
+** P4 is a pointer to a 64-bit integer value.
+** Write that value into register P2.
+*/
+case OP_Int64: {           /* out2 */
+  pOut = out2Prerelease(p, pOp);
+  assert( pOp->p4.pI64!=0 );
+  pOut->u.i = *pOp->p4.pI64;
+  break;
+}
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/* Opcode: Real * P2 * P4 *
+** Synopsis: r[P2]=P4
+**
+** P4 is a pointer to a 64-bit floating point value.
+** Write that value into register P2.
+*/
+case OP_Real: {            /* same as TK_FLOAT, out2 */
+  pOut = out2Prerelease(p, pOp);
+  pOut->flags = MEM_Real;
+  assert( !sqlite3IsNaN(*pOp->p4.pReal) );
+  pOut->u.r = *pOp->p4.pReal;
+  break;
+}
+#endif
+
+/* Opcode: String8 * P2 * P4 *
+** Synopsis: r[P2]='P4'
+**
+** P4 points to a nul terminated UTF-8 string. This opcode is transformed
+** into a String opcode before it is executed for the first time.  During
+** this transformation, the length of string P4 is computed and stored
+** as the P1 parameter.
+*/
+case OP_String8: {         /* same as TK_STRING, out2 */
+  assert( pOp->p4.z!=0 );
+  pOut = out2Prerelease(p, pOp);
+  pOp->p1 = sqlite3Strlen30(pOp->p4.z);
+
+#ifndef SQLITE_OMIT_UTF16
+  if( encoding!=SQLITE_UTF8 ){
+    rc = sqlite3VdbeMemSetStr(pOut, pOp->p4.z, -1, SQLITE_UTF8, SQLITE_STATIC);
+    assert( rc==SQLITE_OK || rc==SQLITE_TOOBIG );
+    if( rc ) goto too_big;
+    if( SQLITE_OK!=sqlite3VdbeChangeEncoding(pOut, encoding) ) goto no_mem;
+    assert( pOut->szMalloc>0 && pOut->zMalloc==pOut->z );
+    assert( VdbeMemDynamic(pOut)==0 );
+    pOut->szMalloc = 0;
+    pOut->flags |= MEM_Static;
+    if( pOp->p4type==P4_DYNAMIC ){
+      sqlite3DbFree(db, pOp->p4.z);
+    }
+    pOp->p4type = P4_DYNAMIC;
+    pOp->p4.z = pOut->z;
+    pOp->p1 = pOut->n;
+  }
+#endif
+  if( pOp->p1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+  pOp->opcode = OP_String;
+  assert( rc==SQLITE_OK );
+  /* Fall through to the next case, OP_String */
+  /* no break */ deliberate_fall_through
+}
+
+/* Opcode: String P1 P2 P3 P4 P5
+** Synopsis: r[P2]='P4' (len=P1)
+**
+** The string value P4 of length P1 (bytes) is stored in register P2.
+**
+** If P3 is not zero and the content of register P3 is equal to P5, then
+** the datatype of the register P2 is converted to BLOB.  The content is
+** the same sequence of bytes, it is merely interpreted as a BLOB instead
+** of a string, as if it had been CAST.  In other words:
+**
+** if( P3!=0 and reg[P3]==P5 ) reg[P2] := CAST(reg[P2] as BLOB)
+*/
+case OP_String: {          /* out2 */
+  assert( pOp->p4.z!=0 );
+  pOut = out2Prerelease(p, pOp);
+  pOut->flags = MEM_Str|MEM_Static|MEM_Term;
+  pOut->z = pOp->p4.z;
+  pOut->n = pOp->p1;
+  pOut->enc = encoding;
+  UPDATE_MAX_BLOBSIZE(pOut);
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+  if( pOp->p3>0 ){
+    assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+    pIn3 = &aMem[pOp->p3];
+    assert( pIn3->flags & MEM_Int );
+    if( pIn3->u.i==pOp->p5 ) pOut->flags = MEM_Blob|MEM_Static|MEM_Term;
+  }
+#endif
+  break;
+}
+
+/* Opcode: BeginSubrtn * P2 * * *
+** Synopsis: r[P2]=NULL
+**
+** Mark the beginning of a subroutine that can be entered in-line
+** or that can be called using OP_Gosub.  The subroutine should
+** be terminated by an OP_Return instruction that has a P1 operand that
+** is the same as the P2 operand to this opcode and that has P3 set to 1.
+** If the subroutine is entered in-line, then the OP_Return will simply
+** fall through.  But if the subroutine is entered using OP_Gosub, then
+** the OP_Return will jump back to the first instruction after the OP_Gosub.
+**
+** This routine works by loading a NULL into the P2 register.  When the
+** return address register contains a NULL, the OP_Return instruction is
+** a no-op that simply falls through to the next instruction (assuming that
+** the OP_Return opcode has a P3 value of 1).  Thus if the subroutine is
+** entered in-line, then the OP_Return will cause in-line execution to
+** continue.  But if the subroutine is entered via OP_Gosub, then the
+** OP_Return will cause a return to the address following the OP_Gosub.
+**
+** This opcode is identical to OP_Null.  It has a different name
+** only to make the byte code easier to read and verify.
+*/
+/* Opcode: Null P1 P2 P3 * *
+** Synopsis: r[P2..P3]=NULL
+**
+** Write a NULL into registers P2.  If P3 greater than P2, then also write
+** NULL into register P3 and every register in between P2 and P3.  If P3
+** is less than P2 (typically P3 is zero) then only register P2 is
+** set to NULL.
+**
+** If the P1 value is non-zero, then also set the MEM_Cleared flag so that
+** NULL values will not compare equal even if SQLITE_NULLEQ is set on
+** OP_Ne or OP_Eq.
+*/
+case OP_BeginSubrtn:
+case OP_Null: {           /* out2 */
+  int cnt;
+  u16 nullFlag;
+  pOut = out2Prerelease(p, pOp);
+  cnt = pOp->p3-pOp->p2;
+  assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+  pOut->flags = nullFlag = pOp->p1 ? (MEM_Null|MEM_Cleared) : MEM_Null;
+  pOut->n = 0;
+#ifdef SQLITE_DEBUG
+  pOut->uTemp = 0;
+#endif
+  while( cnt>0 ){
+    pOut++;
+    memAboutToChange(p, pOut);
+    sqlite3VdbeMemSetNull(pOut);
+    pOut->flags = nullFlag;
+    pOut->n = 0;
+    cnt--;
+  }
+  break;
+}
+
+/* Opcode: SoftNull P1 * * * *
+** Synopsis: r[P1]=NULL
+**
+** Set register P1 to have the value NULL as seen by the OP_MakeRecord
+** instruction, but do not free any string or blob memory associated with
+** the register, so that if the value was a string or blob that was
+** previously copied using OP_SCopy, the copies will continue to be valid.
+*/
+case OP_SoftNull: {
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  pOut = &aMem[pOp->p1];
+  pOut->flags = (pOut->flags&~(MEM_Undefined|MEM_AffMask))|MEM_Null;
+  break;
+}
+
+/* Opcode: Blob P1 P2 * P4 *
+** Synopsis: r[P2]=P4 (len=P1)
+**
+** P4 points to a blob of data P1 bytes long.  Store this
+** blob in register P2.  If P4 is a NULL pointer, then construct
+** a zero-filled blob that is P1 bytes long in P2.
+*/
+case OP_Blob: {                /* out2 */
+  assert( pOp->p1 <= SQLITE_MAX_LENGTH );
+  pOut = out2Prerelease(p, pOp);
+  if( pOp->p4.z==0 ){
+    sqlite3VdbeMemSetZeroBlob(pOut, pOp->p1);
+    if( sqlite3VdbeMemExpandBlob(pOut) ) goto no_mem;
+  }else{
+    sqlite3VdbeMemSetStr(pOut, pOp->p4.z, pOp->p1, 0, 0);
+  }
+  pOut->enc = encoding;
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Variable P1 P2 * * *
+** Synopsis: r[P2]=parameter(P1)
+**
+** Transfer the values of bound parameter P1 into register P2
+*/
+case OP_Variable: {            /* out2 */
+  Mem *pVar;       /* Value being transferred */
+
+  assert( pOp->p1>0 && pOp->p1<=p->nVar );
+  pVar = &p->aVar[pOp->p1 - 1];
+  if( sqlite3VdbeMemTooBig(pVar) ){
+    goto too_big;
+  }
+  pOut = &aMem[pOp->p2];
+  if( VdbeMemDynamic(pOut) ) sqlite3VdbeMemSetNull(pOut);
+  memcpy(pOut, pVar, MEMCELLSIZE);
+  pOut->flags &= ~(MEM_Dyn|MEM_Ephem);
+  pOut->flags |= MEM_Static|MEM_FromBind;
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Move P1 P2 P3 * *
+** Synopsis: r[P2@P3]=r[P1@P3]
+**
+** Move the P3 values in register P1..P1+P3-1 over into
+** registers P2..P2+P3-1.  Registers P1..P1+P3-1 are
+** left holding a NULL.  It is an error for register ranges
+** P1..P1+P3-1 and P2..P2+P3-1 to overlap.  It is an error
+** for P3 to be less than 1.
+*/
+case OP_Move: {
+  int n;           /* Number of registers left to copy */
+  int p1;          /* Register to copy from */
+  int p2;          /* Register to copy to */
+
+  n = pOp->p3;
+  p1 = pOp->p1;
+  p2 = pOp->p2;
+  assert( n>0 && p1>0 && p2>0 );
+  assert( p1+n<=p2 || p2+n<=p1 );
+
+  pIn1 = &aMem[p1];
+  pOut = &aMem[p2];
+  do{
+    assert( pOut<=&aMem[(p->nMem+1 - p->nCursor)] );
+    assert( pIn1<=&aMem[(p->nMem+1 - p->nCursor)] );
+    assert( memIsValid(pIn1) );
+    memAboutToChange(p, pOut);
+    sqlite3VdbeMemMove(pOut, pIn1);
+#ifdef SQLITE_DEBUG
+    pIn1->pScopyFrom = 0;
+    { int i;
+      for(i=1; i<p->nMem; i++){
+        if( aMem[i].pScopyFrom==pIn1 ){
+          assert( aMem[i].bScopy );
+          aMem[i].pScopyFrom = pOut;
+        }
+      }
+    }
+#endif
+    Deephemeralize(pOut);
+    REGISTER_TRACE(p2++, pOut);
+    pIn1++;
+    pOut++;
+  }while( --n );
+  break;
+}
+
+/* Opcode: Copy P1 P2 P3 * P5
+** Synopsis: r[P2@P3+1]=r[P1@P3+1]
+**
+** Make a copy of registers P1..P1+P3 into registers P2..P2+P3.
+**
+** If the 0x0002 bit of P5 is set then also clear the MEM_Subtype flag in the
+** destination.  The 0x0001 bit of P5 indicates that this Copy opcode cannot
+** be merged.  The 0x0001 bit is used by the query planner and does not
+** come into play during query execution.
+**
+** This instruction makes a deep copy of the value.  A duplicate
+** is made of any string or blob constant.  See also OP_SCopy.
+*/
+case OP_Copy: {
+  int n;
+
+  n = pOp->p3;
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  assert( pOut!=pIn1 );
+  while( 1 ){
+    memAboutToChange(p, pOut);
+    sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
+    Deephemeralize(pOut);
+    if( (pOut->flags & MEM_Subtype)!=0 &&  (pOp->p5 & 0x0002)!=0 ){
+      pOut->flags &= ~MEM_Subtype;
+    }
+#ifdef SQLITE_DEBUG
+    pOut->pScopyFrom = 0;
+#endif
+    REGISTER_TRACE(pOp->p2+pOp->p3-n, pOut);
+    if( (n--)==0 ) break;
+    pOut++;
+    pIn1++;
+  }
+  break;
+}
+
+/* Opcode: SCopy P1 P2 * * *
+** Synopsis: r[P2]=r[P1]
+**
+** Make a shallow copy of register P1 into register P2.
+**
+** This instruction makes a shallow copy of the value.  If the value
+** is a string or blob, then the copy is only a pointer to the
+** original and hence if the original changes so will the copy.
+** Worse, if the original is deallocated, the copy becomes invalid.
+** Thus the program must guarantee that the original will not change
+** during the lifetime of the copy.  Use OP_Copy to make a complete
+** copy.
+*/
+case OP_SCopy: {            /* out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  assert( pOut!=pIn1 );
+  sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
+#ifdef SQLITE_DEBUG
+  pOut->pScopyFrom = pIn1;
+  pOut->mScopyFlags = pIn1->flags;
+  pIn1->bScopy = 1;
+#endif
+  break;
+}
+
+/* Opcode: IntCopy P1 P2 * * *
+** Synopsis: r[P2]=r[P1]
+**
+** Transfer the integer value held in register P1 into register P2.
+**
+** This is an optimized version of SCopy that works only for integer
+** values.
+*/
+case OP_IntCopy: {            /* out2 */
+  pIn1 = &aMem[pOp->p1];
+  assert( (pIn1->flags & MEM_Int)!=0 );
+  pOut = &aMem[pOp->p2];
+  sqlite3VdbeMemSetInt64(pOut, pIn1->u.i);
+  break;
+}
+
+/* Opcode: FkCheck * * * * *
+**
+** Halt with an SQLITE_CONSTRAINT error if there are any unresolved
+** foreign key constraint violations.  If there are no foreign key
+** constraint violations, this is a no-op.
+**
+** FK constraint violations are also checked when the prepared statement
+** exits.  This opcode is used to raise foreign key constraint errors prior
+** to returning results such as a row change count or the result of a
+** RETURNING clause.
+*/
+case OP_FkCheck: {
+  if( (rc = sqlite3VdbeCheckFk(p,0))!=SQLITE_OK ){
+    goto abort_due_to_error;
+  }
+  break;
+}
+
+/* Opcode: ResultRow P1 P2 * * *
+** Synopsis: output=r[P1@P2]
+**
+** The registers P1 through P1+P2-1 contain a single row of
+** results. This opcode causes the sqlite3_step() call to terminate
+** with an SQLITE_ROW return code and it sets up the sqlite3_stmt
+** structure to provide access to the r(P1)..r(P1+P2-1) values as
+** the result row.
+*/
+case OP_ResultRow: {
+  assert( p->nResColumn==pOp->p2 );
+  assert( pOp->p1>0 || CORRUPT_DB );
+  assert( pOp->p1+pOp->p2<=(p->nMem+1 - p->nCursor)+1 );
+
+  p->cacheCtr = (p->cacheCtr + 2)|1;
+  p->pResultRow = &aMem[pOp->p1];
+#ifdef SQLITE_DEBUG
+  {
+    Mem *pMem = p->pResultRow;
+    int i;
+    for(i=0; i<pOp->p2; i++){
+      assert( memIsValid(&pMem[i]) );
+      REGISTER_TRACE(pOp->p1+i, &pMem[i]);
+      /* The registers in the result will not be used again when the
+      ** prepared statement restarts.  This is because sqlite3_column()
+      ** APIs might have caused type conversions of made other changes to
+      ** the register values.  Therefore, we can go ahead and break any
+      ** OP_SCopy dependencies. */
+      pMem[i].pScopyFrom = 0;
+    }
+  }
+#endif
+  if( db->mallocFailed ) goto no_mem;
+  if( db->mTrace & SQLITE_TRACE_ROW ){
+    db->trace.xV2(SQLITE_TRACE_ROW, db->pTraceArg, p, 0);
+  }
+  p->pc = (int)(pOp - aOp) + 1;
+  rc = SQLITE_ROW;
+  goto vdbe_return;
+}
+
+/* Opcode: Concat P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]+r[P1]
+**
+** Add the text in register P1 onto the end of the text in
+** register P2 and store the result in register P3.
+** If either the P1 or P2 text are NULL then store NULL in P3.
+**
+**   P3 = P2 || P1
+**
+** It is illegal for P1 and P3 to be the same register. Sometimes,
+** if P3 is the same register as P2, the implementation is able
+** to avoid a memcpy().
+*/
+case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
+  i64 nByte;          /* Total size of the output string or blob */
+  u16 flags1;         /* Initial flags for P1 */
+  u16 flags2;         /* Initial flags for P2 */
+
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  pOut = &aMem[pOp->p3];
+  testcase( pOut==pIn2 );
+  assert( pIn1!=pOut );
+  flags1 = pIn1->flags;
+  testcase( flags1 & MEM_Null );
+  testcase( pIn2->flags & MEM_Null );
+  if( (flags1 | pIn2->flags) & MEM_Null ){
+    sqlite3VdbeMemSetNull(pOut);
+    break;
+  }
+  if( (flags1 & (MEM_Str|MEM_Blob))==0 ){
+    if( sqlite3VdbeMemStringify(pIn1,encoding,0) ) goto no_mem;
+    flags1 = pIn1->flags & ~MEM_Str;
+  }else if( (flags1 & MEM_Zero)!=0 ){
+    if( sqlite3VdbeMemExpandBlob(pIn1) ) goto no_mem;
+    flags1 = pIn1->flags & ~MEM_Str;
+  }
+  flags2 = pIn2->flags;
+  if( (flags2 & (MEM_Str|MEM_Blob))==0 ){
+    if( sqlite3VdbeMemStringify(pIn2,encoding,0) ) goto no_mem;
+    flags2 = pIn2->flags & ~MEM_Str;
+  }else if( (flags2 & MEM_Zero)!=0 ){
+    if( sqlite3VdbeMemExpandBlob(pIn2) ) goto no_mem;
+    flags2 = pIn2->flags & ~MEM_Str;
+  }
+  nByte = pIn1->n + pIn2->n;
+  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+  if( sqlite3VdbeMemGrow(pOut, (int)nByte+2, pOut==pIn2) ){
+    goto no_mem;
+  }
+  MemSetTypeFlag(pOut, MEM_Str);
+  if( pOut!=pIn2 ){
+    memcpy(pOut->z, pIn2->z, pIn2->n);
+    assert( (pIn2->flags & MEM_Dyn) == (flags2 & MEM_Dyn) );
+    pIn2->flags = flags2;
+  }
+  memcpy(&pOut->z[pIn2->n], pIn1->z, pIn1->n);
+  assert( (pIn1->flags & MEM_Dyn) == (flags1 & MEM_Dyn) );
+  pIn1->flags = flags1;
+  if( encoding>SQLITE_UTF8 ) nByte &= ~1;
+  pOut->z[nByte]=0;
+  pOut->z[nByte+1] = 0;
+  pOut->flags |= MEM_Term;
+  pOut->n = (int)nByte;
+  pOut->enc = encoding;
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Add P1 P2 P3 * *
+** Synopsis: r[P3]=r[P1]+r[P2]
+**
+** Add the value in register P1 to the value in register P2
+** and store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Multiply P1 P2 P3 * *
+** Synopsis: r[P3]=r[P1]*r[P2]
+**
+**
+** Multiply the value in register P1 by the value in register P2
+** and store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Subtract P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]-r[P1]
+**
+** Subtract the value in register P1 from the value in register P2
+** and store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Divide P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]/r[P1]
+**
+** Divide the value in register P1 by the value in register P2
+** and store the result in register P3 (P3=P2/P1). If the value in
+** register P1 is zero, then the result is NULL. If either input is
+** NULL, the result is NULL.
+*/
+/* Opcode: Remainder P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]%r[P1]
+**
+** Compute the remainder after integer register P2 is divided by
+** register P1 and store the result in register P3.
+** If the value in register P1 is zero the result is NULL.
+** If either operand is NULL, the result is NULL.
+*/
+case OP_Add:                   /* same as TK_PLUS, in1, in2, out3 */
+case OP_Subtract:              /* same as TK_MINUS, in1, in2, out3 */
+case OP_Multiply:              /* same as TK_STAR, in1, in2, out3 */
+case OP_Divide:                /* same as TK_SLASH, in1, in2, out3 */
+case OP_Remainder: {           /* same as TK_REM, in1, in2, out3 */
+  u16 type1;      /* Numeric type of left operand */
+  u16 type2;      /* Numeric type of right operand */
+  i64 iA;         /* Integer value of left operand */
+  i64 iB;         /* Integer value of right operand */
+  double rA;      /* Real value of left operand */
+  double rB;      /* Real value of right operand */
+
+  pIn1 = &aMem[pOp->p1];
+  type1 = pIn1->flags;
+  pIn2 = &aMem[pOp->p2];
+  type2 = pIn2->flags;
+  pOut = &aMem[pOp->p3];
+  if( (type1 & type2 & MEM_Int)!=0 ){
+int_math:
+    iA = pIn1->u.i;
+    iB = pIn2->u.i;
+    switch( pOp->opcode ){
+      case OP_Add:       if( sqlite3AddInt64(&iB,iA) ) goto fp_math;  break;
+      case OP_Subtract:  if( sqlite3SubInt64(&iB,iA) ) goto fp_math;  break;
+      case OP_Multiply:  if( sqlite3MulInt64(&iB,iA) ) goto fp_math;  break;
+      case OP_Divide: {
+        if( iA==0 ) goto arithmetic_result_is_null;
+        if( iA==-1 && iB==SMALLEST_INT64 ) goto fp_math;
+        iB /= iA;
+        break;
+      }
+      default: {
+        if( iA==0 ) goto arithmetic_result_is_null;
+        if( iA==-1 ) iA = 1;
+        iB %= iA;
+        break;
+      }
+    }
+    pOut->u.i = iB;
+    MemSetTypeFlag(pOut, MEM_Int);
+  }else if( ((type1 | type2) & MEM_Null)!=0 ){
+    goto arithmetic_result_is_null;
+  }else{
+    type1 = numericType(pIn1);
+    type2 = numericType(pIn2);
+    if( (type1 & type2 & MEM_Int)!=0 ) goto int_math;
+fp_math:
+    rA = sqlite3VdbeRealValue(pIn1);
+    rB = sqlite3VdbeRealValue(pIn2);
+    switch( pOp->opcode ){
+      case OP_Add:         rB += rA;       break;
+      case OP_Subtract:    rB -= rA;       break;
+      case OP_Multiply:    rB *= rA;       break;
+      case OP_Divide: {
+        /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+        if( rA==(double)0 ) goto arithmetic_result_is_null;
+        rB /= rA;
+        break;
+      }
+      default: {
+        iA = sqlite3VdbeIntValue(pIn1);
+        iB = sqlite3VdbeIntValue(pIn2);
+        if( iA==0 ) goto arithmetic_result_is_null;
+        if( iA==-1 ) iA = 1;
+        rB = (double)(iB % iA);
+        break;
+      }
+    }
+#ifdef SQLITE_OMIT_FLOATING_POINT
+    pOut->u.i = rB;
+    MemSetTypeFlag(pOut, MEM_Int);
+#else
+    if( sqlite3IsNaN(rB) ){
+      goto arithmetic_result_is_null;
+    }
+    pOut->u.r = rB;
+    MemSetTypeFlag(pOut, MEM_Real);
+#endif
+  }
+  break;
+
+arithmetic_result_is_null:
+  sqlite3VdbeMemSetNull(pOut);
+  break;
+}
+
+/* Opcode: CollSeq P1 * * P4
+**
+** P4 is a pointer to a CollSeq object. If the next call to a user function
+** or aggregate calls sqlite3GetFuncCollSeq(), this collation sequence will
+** be returned. This is used by the built-in min(), max() and nullif()
+** functions.
+**
+** If P1 is not zero, then it is a register that a subsequent min() or
+** max() aggregate will set to 1 if the current row is not the minimum or
+** maximum.  The P1 register is initialized to 0 by this instruction.
+**
+** The interface used by the implementation of the aforementioned functions
+** to retrieve the collation sequence set by this opcode is not available
+** publicly.  Only built-in functions have access to this feature.
+*/
+case OP_CollSeq: {
+  assert( pOp->p4type==P4_COLLSEQ );
+  if( pOp->p1 ){
+    sqlite3VdbeMemSetInt64(&aMem[pOp->p1], 0);
+  }
+  break;
+}
+
+/* Opcode: BitAnd P1 P2 P3 * *
+** Synopsis: r[P3]=r[P1]&r[P2]
+**
+** Take the bit-wise AND of the values in register P1 and P2 and
+** store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: BitOr P1 P2 P3 * *
+** Synopsis: r[P3]=r[P1]|r[P2]
+**
+** Take the bit-wise OR of the values in register P1 and P2 and
+** store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: ShiftLeft P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]<<r[P1]
+**
+** Shift the integer value in register P2 to the left by the
+** number of bits specified by the integer in register P1.
+** Store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: ShiftRight P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]>>r[P1]
+**
+** Shift the integer value in register P2 to the right by the
+** number of bits specified by the integer in register P1.
+** Store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+case OP_BitAnd:                 /* same as TK_BITAND, in1, in2, out3 */
+case OP_BitOr:                  /* same as TK_BITOR, in1, in2, out3 */
+case OP_ShiftLeft:              /* same as TK_LSHIFT, in1, in2, out3 */
+case OP_ShiftRight: {           /* same as TK_RSHIFT, in1, in2, out3 */
+  i64 iA;
+  u64 uA;
+  i64 iB;
+  u8 op;
+
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  pOut = &aMem[pOp->p3];
+  if( (pIn1->flags | pIn2->flags) & MEM_Null ){
+    sqlite3VdbeMemSetNull(pOut);
+    break;
+  }
+  iA = sqlite3VdbeIntValue(pIn2);
+  iB = sqlite3VdbeIntValue(pIn1);
+  op = pOp->opcode;
+  if( op==OP_BitAnd ){
+    iA &= iB;
+  }else if( op==OP_BitOr ){
+    iA |= iB;
+  }else if( iB!=0 ){
+    assert( op==OP_ShiftRight || op==OP_ShiftLeft );
+
+    /* If shifting by a negative amount, shift in the other direction */
+    if( iB<0 ){
+      assert( OP_ShiftRight==OP_ShiftLeft+1 );
+      op = 2*OP_ShiftLeft + 1 - op;
+      iB = iB>(-64) ? -iB : 64;
+    }
+
+    if( iB>=64 ){
+      iA = (iA>=0 || op==OP_ShiftLeft) ? 0 : -1;
+    }else{
+      memcpy(&uA, &iA, sizeof(uA));
+      if( op==OP_ShiftLeft ){
+        uA <<= iB;
+      }else{
+        uA >>= iB;
+        /* Sign-extend on a right shift of a negative number */
+        if( iA<0 ) uA |= ((((u64)0xffffffff)<<32)|0xffffffff) << (64-iB);
+      }
+      memcpy(&iA, &uA, sizeof(iA));
+    }
+  }
+  pOut->u.i = iA;
+  MemSetTypeFlag(pOut, MEM_Int);
+  break;
+}
+
+/* Opcode: AddImm  P1 P2 * * *
+** Synopsis: r[P1]=r[P1]+P2
+**
+** Add the constant P2 to the value in register P1.
+** The result is always an integer.
+**
+** To force any register to be an integer, just add 0.
+*/
+case OP_AddImm: {            /* in1 */
+  pIn1 = &aMem[pOp->p1];
+  memAboutToChange(p, pIn1);
+  sqlite3VdbeMemIntegerify(pIn1);
+  *(u64*)&pIn1->u.i += (u64)pOp->p2;
+  break;
+}
+
+/* Opcode: MustBeInt P1 P2 * * *
+**
+** Force the value in register P1 to be an integer.  If the value
+** in P1 is not an integer and cannot be converted into an integer
+** without data loss, then jump immediately to P2, or if P2==0
+** raise an SQLITE_MISMATCH exception.
+*/
+case OP_MustBeInt: {            /* jump0, in1 */
+  pIn1 = &aMem[pOp->p1];
+  if( (pIn1->flags & MEM_Int)==0 ){
+    applyAffinity(pIn1, SQLITE_AFF_NUMERIC, encoding);
+    if( (pIn1->flags & MEM_Int)==0 ){
+      VdbeBranchTaken(1, 2);
+      if( pOp->p2==0 ){
+        rc = SQLITE_MISMATCH;
+        goto abort_due_to_error;
+      }else{
+        goto jump_to_p2;
+      }
+    }
+  }
+  VdbeBranchTaken(0, 2);
+  MemSetTypeFlag(pIn1, MEM_Int);
+  break;
+}
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/* Opcode: RealAffinity P1 * * * *
+**
+** If register P1 holds an integer convert it to a real value.
+**
+** This opcode is used when extracting information from a column that
+** has REAL affinity.  Such column values may still be stored as
+** integers, for space efficiency, but after extraction we want them
+** to have only a real value.
+*/
+case OP_RealAffinity: {                  /* in1 */
+  pIn1 = &aMem[pOp->p1];
+  if( pIn1->flags & (MEM_Int|MEM_IntReal) ){
+    testcase( pIn1->flags & MEM_Int );
+    testcase( pIn1->flags & MEM_IntReal );
+    sqlite3VdbeMemRealify(pIn1);
+    REGISTER_TRACE(pOp->p1, pIn1);
+  }
+  break;
+}
+#endif
+
+#if !defined(SQLITE_OMIT_CAST) || !defined(SQLITE_OMIT_ANALYZE)
+/* Opcode: Cast P1 P2 * * *
+** Synopsis: affinity(r[P1])
+**
+** Force the value in register P1 to be the type defined by P2.
+**
+** <ul>
+** <li> P2=='A' → BLOB
+** <li> P2=='B' → TEXT
+** <li> P2=='C' → NUMERIC
+** <li> P2=='D' → INTEGER
+** <li> P2=='E' → REAL
+** </ul>
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_Cast: {                  /* in1 */
+  assert( pOp->p2>=SQLITE_AFF_BLOB && pOp->p2<=SQLITE_AFF_REAL );
+  testcase( pOp->p2==SQLITE_AFF_TEXT );
+  testcase( pOp->p2==SQLITE_AFF_BLOB );
+  testcase( pOp->p2==SQLITE_AFF_NUMERIC );
+  testcase( pOp->p2==SQLITE_AFF_INTEGER );
+  testcase( pOp->p2==SQLITE_AFF_REAL );
+  pIn1 = &aMem[pOp->p1];
+  memAboutToChange(p, pIn1);
+  rc = ExpandBlob(pIn1);
+  if( rc ) goto abort_due_to_error;
+  rc = sqlite3VdbeMemCast(pIn1, pOp->p2, encoding);
+  if( rc ) goto abort_due_to_error;
+  UPDATE_MAX_BLOBSIZE(pIn1);
+  REGISTER_TRACE(pOp->p1, pIn1);
+  break;
+}
+#endif /* SQLITE_OMIT_CAST */
+
+/* Opcode: Eq P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]==r[P1]
+**
+** Compare the values in register P1 and P3.  If reg(P3)==reg(P1) then
+** jump to address P2.
+**
+** The SQLITE_AFF_MASK portion of P5 must be an affinity character -
+** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made
+** to coerce both inputs according to this affinity before the
+** comparison is made. If the SQLITE_AFF_MASK is 0x00, then numeric
+** affinity is used. Note that the affinity conversions are stored
+** back into the input registers P1 and P3.  So this opcode can cause
+** persistent changes to registers P1 and P3.
+**
+** Once any conversions have taken place, and neither value is NULL,
+** the values are compared. If both values are blobs then memcmp() is
+** used to determine the results of the comparison.  If both values
+** are text, then the appropriate collating function specified in
+** P4 is used to do the comparison.  If P4 is not specified then
+** memcmp() is used to compare text string.  If both values are
+** numeric, then a numeric comparison is used. If the two values
+** are of different types, then numbers are considered less than
+** strings and strings are considered less than blobs.
+**
+** If SQLITE_NULLEQ is set in P5 then the result of comparison is always either
+** true or false and is never NULL.  If both operands are NULL then the result
+** of comparison is true.  If either operand is NULL then the result is false.
+** If neither operand is NULL the result is the same as it would be if
+** the SQLITE_NULLEQ flag were omitted from P5.
+**
+** This opcode saves the result of comparison for use by the new
+** OP_Jump opcode.
+*/
+/* Opcode: Ne P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]!=r[P1]
+**
+** This works just like the Eq opcode except that the jump is taken if
+** the operands in registers P1 and P3 are not equal.  See the Eq opcode for
+** additional information.
+*/
+/* Opcode: Lt P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]<r[P1]
+**
+** Compare the values in register P1 and P3.  If reg(P3)<reg(P1) then
+** jump to address P2.
+**
+** If the SQLITE_JUMPIFNULL bit of P5 is set and either reg(P1) or
+** reg(P3) is NULL then the take the jump.  If the SQLITE_JUMPIFNULL
+** bit is clear then fall through if either operand is NULL.
+**
+** The SQLITE_AFF_MASK portion of P5 must be an affinity character -
+** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made
+** to coerce both inputs according to this affinity before the
+** comparison is made. If the SQLITE_AFF_MASK is 0x00, then numeric
+** affinity is used. Note that the affinity conversions are stored
+** back into the input registers P1 and P3.  So this opcode can cause
+** persistent changes to registers P1 and P3.
+**
+** Once any conversions have taken place, and neither value is NULL,
+** the values are compared. If both values are blobs then memcmp() is
+** used to determine the results of the comparison.  If both values
+** are text, then the appropriate collating function specified in
+** P4 is  used to do the comparison.  If P4 is not specified then
+** memcmp() is used to compare text string.  If both values are
+** numeric, then a numeric comparison is used. If the two values
+** are of different types, then numbers are considered less than
+** strings and strings are considered less than blobs.
+**
+** This opcode saves the result of comparison for use by the new
+** OP_Jump opcode.
+*/
+/* Opcode: Le P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]<=r[P1]
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the content of register P3 is less than or equal to the content of
+** register P1.  See the Lt opcode for additional information.
+*/
+/* Opcode: Gt P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]>r[P1]
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the content of register P3 is greater than the content of
+** register P1.  See the Lt opcode for additional information.
+*/
+/* Opcode: Ge P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]>=r[P1]
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the content of register P3 is greater than or equal to the content of
+** register P1.  See the Lt opcode for additional information.
+*/
+case OP_Eq:               /* same as TK_EQ, jump, in1, in3 */
+case OP_Ne:               /* same as TK_NE, jump, in1, in3 */
+case OP_Lt:               /* same as TK_LT, jump, in1, in3 */
+case OP_Le:               /* same as TK_LE, jump, in1, in3 */
+case OP_Gt:               /* same as TK_GT, jump, in1, in3 */
+case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
+  int res, res2;      /* Result of the comparison of pIn1 against pIn3 */
+  char affinity;      /* Affinity to use for comparison */
+  u16 flags1;         /* Copy of initial value of pIn1->flags */
+  u16 flags3;         /* Copy of initial value of pIn3->flags */
+
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
+  flags1 = pIn1->flags;
+  flags3 = pIn3->flags;
+  if( (flags1 & flags3 & MEM_Int)!=0 ){
+    /* Common case of comparison of two integers */
+    if( pIn3->u.i > pIn1->u.i ){
+      if( sqlite3aGTb[pOp->opcode] ){
+        VdbeBranchTaken(1, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+        goto jump_to_p2;
+      }
+      iCompare = +1;
+      VVA_ONLY( iCompareIsInit = 1; )
+    }else if( pIn3->u.i < pIn1->u.i ){
+      if( sqlite3aLTb[pOp->opcode] ){
+        VdbeBranchTaken(1, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+        goto jump_to_p2;
+      }
+      iCompare = -1;
+      VVA_ONLY( iCompareIsInit = 1; )
+    }else{
+      if( sqlite3aEQb[pOp->opcode] ){
+        VdbeBranchTaken(1, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+        goto jump_to_p2;
+      }
+      iCompare = 0;
+      VVA_ONLY( iCompareIsInit = 1; )
+    }
+    VdbeBranchTaken(0, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+    break;
+  }
+  if( (flags1 | flags3)&MEM_Null ){
+    /* One or both operands are NULL */
+    if( pOp->p5 & SQLITE_NULLEQ ){
+      /* If SQLITE_NULLEQ is set (which will only happen if the operator is
+      ** OP_Eq or OP_Ne) then take the jump or not depending on whether
+      ** or not both operands are null.
+      */
+      assert( (flags1 & MEM_Cleared)==0 );
+      assert( (pOp->p5 & SQLITE_JUMPIFNULL)==0 || CORRUPT_DB );
+      testcase( (pOp->p5 & SQLITE_JUMPIFNULL)!=0 );
+      if( (flags1&flags3&MEM_Null)!=0
+       && (flags3&MEM_Cleared)==0
+      ){
+        res = 0;  /* Operands are equal */
+      }else{
+        res = ((flags3 & MEM_Null) ? -1 : +1);  /* Operands are not equal */
+      }
+    }else{
+      /* SQLITE_NULLEQ is clear and at least one operand is NULL,
+      ** then the result is always NULL.
+      ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
+      */
+      VdbeBranchTaken(2,3);
+      if( pOp->p5 & SQLITE_JUMPIFNULL ){
+        goto jump_to_p2;
+      }
+      iCompare = 1;    /* Operands are not equal */
+      VVA_ONLY( iCompareIsInit = 1; )
+      break;
+    }
+  }else{
+    /* Neither operand is NULL and we couldn't do the special high-speed
+    ** integer comparison case.  So do a general-case comparison. */
+    affinity = pOp->p5 & SQLITE_AFF_MASK;
+    if( affinity>=SQLITE_AFF_NUMERIC ){
+      if( (flags1 | flags3)&MEM_Str ){
+        if( (flags1 & (MEM_Int|MEM_IntReal|MEM_Real|MEM_Str))==MEM_Str ){
+          applyNumericAffinity(pIn1,0);
+          assert( flags3==pIn3->flags || CORRUPT_DB );
+          flags3 = pIn3->flags;
+        }
+        if( (flags3 & (MEM_Int|MEM_IntReal|MEM_Real|MEM_Str))==MEM_Str ){
+          applyNumericAffinity(pIn3,0);
+        }
+      }
+    }else if( affinity==SQLITE_AFF_TEXT && ((flags1 | flags3) & MEM_Str)!=0 ){
+      if( (flags1 & MEM_Str)!=0 ){
+        pIn1->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal);
+      }else if( (flags1&(MEM_Int|MEM_Real|MEM_IntReal))!=0 ){
+        testcase( pIn1->flags & MEM_Int );
+        testcase( pIn1->flags & MEM_Real );
+        testcase( pIn1->flags & MEM_IntReal );
+        sqlite3VdbeMemStringify(pIn1, encoding, 1);
+        testcase( (flags1&MEM_Dyn) != (pIn1->flags&MEM_Dyn) );
+        flags1 = (pIn1->flags & ~MEM_TypeMask) | (flags1 & MEM_TypeMask);
+        if( NEVER(pIn1==pIn3) ) flags3 = flags1 | MEM_Str;
+      }
+      if( (flags3 & MEM_Str)!=0 ){
+        pIn3->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal);
+      }else if( (flags3&(MEM_Int|MEM_Real|MEM_IntReal))!=0 ){
+        testcase( pIn3->flags & MEM_Int );
+        testcase( pIn3->flags & MEM_Real );
+        testcase( pIn3->flags & MEM_IntReal );
+        sqlite3VdbeMemStringify(pIn3, encoding, 1);
+        testcase( (flags3&MEM_Dyn) != (pIn3->flags&MEM_Dyn) );
+        flags3 = (pIn3->flags & ~MEM_TypeMask) | (flags3 & MEM_TypeMask);
+      }
+    }
+    assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );
+    res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);
+  }
+
+  /* At this point, res is negative, zero, or positive if reg[P1] is
+  ** less than, equal to, or greater than reg[P3], respectively.  Compute
+  ** the answer to this operator in res2, depending on what the comparison
+  ** operator actually is.  The next block of code depends on the fact
+  ** that the 6 comparison operators are consecutive integers in this
+  ** order:  NE, EQ, GT, LE, LT, GE */
+  assert( OP_Eq==OP_Ne+1 ); assert( OP_Gt==OP_Ne+2 ); assert( OP_Le==OP_Ne+3 );
+  assert( OP_Lt==OP_Ne+4 ); assert( OP_Ge==OP_Ne+5 );
+  if( res<0 ){
+    res2 = sqlite3aLTb[pOp->opcode];
+  }else if( res==0 ){
+    res2 = sqlite3aEQb[pOp->opcode];
+  }else{
+    res2 = sqlite3aGTb[pOp->opcode];
+  }
+  iCompare = res;
+  VVA_ONLY( iCompareIsInit = 1; )
+
+  /* Undo any changes made by applyAffinity() to the input registers. */
+  assert( (pIn3->flags & MEM_Dyn) == (flags3 & MEM_Dyn) );
+  pIn3->flags = flags3;
+  assert( (pIn1->flags & MEM_Dyn) == (flags1 & MEM_Dyn) );
+  pIn1->flags = flags1;
+
+  VdbeBranchTaken(res2!=0, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+  if( res2 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: ElseEq * P2 * * *
+**
+** This opcode must follow an OP_Lt or OP_Gt comparison operator.  There
+** can be zero or more OP_ReleaseReg opcodes intervening, but no other
+** opcodes are allowed to occur between this instruction and the previous
+** OP_Lt or OP_Gt.
+**
+** If the result of an OP_Eq comparison on the same two operands as
+** the prior OP_Lt or OP_Gt would have been true, then jump to P2.  If
+** the result of an OP_Eq comparison on the two previous operands
+** would have been false or NULL, then fall through.
+*/
+case OP_ElseEq: {       /* same as TK_ESCAPE, jump */
+
+#ifdef SQLITE_DEBUG
+  /* Verify the preconditions of this opcode - that it follows an OP_Lt or
+  ** OP_Gt with zero or more intervening OP_ReleaseReg opcodes */
+  int iAddr;
+  for(iAddr = (int)(pOp - aOp) - 1; ALWAYS(iAddr>=0); iAddr--){
+    if( aOp[iAddr].opcode==OP_ReleaseReg ) continue;
+    assert( aOp[iAddr].opcode==OP_Lt || aOp[iAddr].opcode==OP_Gt );
+    break;
+  }
+#endif /* SQLITE_DEBUG */
+  assert( iCompareIsInit );
+  VdbeBranchTaken(iCompare==0, 2);
+  if( iCompare==0 ) goto jump_to_p2;
+  break;
+}
+
+
+/* Opcode: Permutation * * * P4 *
+**
+** Set the permutation used by the OP_Compare operator in the next
+** instruction.  The permutation is stored in the P4 operand.
+**
+** The permutation is only valid for the next opcode which must be
+** an OP_Compare that has the OPFLAG_PERMUTE bit set in P5.
+**
+** The first integer in the P4 integer array is the length of the array
+** and does not become part of the permutation.
+*/
+case OP_Permutation: {
+  assert( pOp->p4type==P4_INTARRAY );
+  assert( pOp->p4.ai );
+  assert( pOp[1].opcode==OP_Compare );
+  assert( pOp[1].p5 & OPFLAG_PERMUTE );
+  break;
+}
+
+/* Opcode: Compare P1 P2 P3 P4 P5
+** Synopsis: r[P1@P3] <-> r[P2@P3]
+**
+** Compare two vectors of registers in reg(P1)..reg(P1+P3-1) (call this
+** vector "A") and in reg(P2)..reg(P2+P3-1) ("B").  Save the result of
+** the comparison for use by the next OP_Jump instruct.
+**
+** If P5 has the OPFLAG_PERMUTE bit set, then the order of comparison is
+** determined by the most recent OP_Permutation operator.  If the
+** OPFLAG_PERMUTE bit is clear, then register are compared in sequential
+** order.
+**
+** P4 is a KeyInfo structure that defines collating sequences and sort
+** orders for the comparison.  The permutation applies to registers
+** only.  The KeyInfo elements are used sequentially.
+**
+** The comparison is a sort comparison, so NULLs compare equal,
+** NULLs are less than numbers, numbers are less than strings,
+** and strings are less than blobs.
+**
+** This opcode must be immediately followed by an OP_Jump opcode.
+*/
+case OP_Compare: {
+  int n;
+  int i;
+  int p1;
+  int p2;
+  const KeyInfo *pKeyInfo;
+  u32 idx;
+  CollSeq *pColl;    /* Collating sequence to use on this term */
+  int bRev;          /* True for DESCENDING sort order */
+  u32 *aPermute;     /* The permutation */
+
+  if( (pOp->p5 & OPFLAG_PERMUTE)==0 ){
+    aPermute = 0;
+  }else{
+    assert( pOp>aOp );
+    assert( pOp[-1].opcode==OP_Permutation );
+    assert( pOp[-1].p4type==P4_INTARRAY );
+    aPermute = pOp[-1].p4.ai + 1;
+    assert( aPermute!=0 );
+  }
+  n = pOp->p3;
+  pKeyInfo = pOp->p4.pKeyInfo;
+  assert( n>0 );
+  assert( pKeyInfo!=0 );
+  p1 = pOp->p1;
+  p2 = pOp->p2;
+#ifdef SQLITE_DEBUG
+  if( aPermute ){
+    int k, mx = 0;
+    for(k=0; k<n; k++) if( aPermute[k]>(u32)mx ) mx = aPermute[k];
+    assert( p1>0 && p1+mx<=(p->nMem+1 - p->nCursor)+1 );
+    assert( p2>0 && p2+mx<=(p->nMem+1 - p->nCursor)+1 );
+  }else{
+    assert( p1>0 && p1+n<=(p->nMem+1 - p->nCursor)+1 );
+    assert( p2>0 && p2+n<=(p->nMem+1 - p->nCursor)+1 );
+  }
+#endif /* SQLITE_DEBUG */
+  for(i=0; i<n; i++){
+    idx = aPermute ? aPermute[i] : (u32)i;
+    assert( memIsValid(&aMem[p1+idx]) );
+    assert( memIsValid(&aMem[p2+idx]) );
+    REGISTER_TRACE(p1+idx, &aMem[p1+idx]);
+    REGISTER_TRACE(p2+idx, &aMem[p2+idx]);
+    assert( i<pKeyInfo->nKeyField );
+    pColl = pKeyInfo->aColl[i];
+    bRev = (pKeyInfo->aSortFlags[i] & KEYINFO_ORDER_DESC);
+    iCompare = sqlite3MemCompare(&aMem[p1+idx], &aMem[p2+idx], pColl);
+    VVA_ONLY( iCompareIsInit = 1; )
+    if( iCompare ){
+      if( (pKeyInfo->aSortFlags[i] & KEYINFO_ORDER_BIGNULL)
+       && ((aMem[p1+idx].flags & MEM_Null) || (aMem[p2+idx].flags & MEM_Null))
+      ){
+        iCompare = -iCompare;
+      }
+      if( bRev ) iCompare = -iCompare;
+      break;
+    }
+  }
+  assert( pOp[1].opcode==OP_Jump );
+  break;
+}
+
+/* Opcode: Jump P1 P2 P3 * *
+**
+** Jump to the instruction at address P1, P2, or P3 depending on whether
+** in the most recent OP_Compare instruction the P1 vector was less than,
+** equal to, or greater than the P2 vector, respectively.
+**
+** This opcode must immediately follow an OP_Compare opcode.
+*/
+case OP_Jump: {             /* jump */
+  assert( pOp>aOp && pOp[-1].opcode==OP_Compare );
+  assert( iCompareIsInit );
+  if( iCompare<0 ){
+    VdbeBranchTaken(0,4); pOp = &aOp[pOp->p1 - 1];
+  }else if( iCompare==0 ){
+    VdbeBranchTaken(1,4); pOp = &aOp[pOp->p2 - 1];
+  }else{
+    VdbeBranchTaken(2,4); pOp = &aOp[pOp->p3 - 1];
+  }
+  break;
+}
+
+/* Opcode: And P1 P2 P3 * *
+** Synopsis: r[P3]=(r[P1] && r[P2])
+**
+** Take the logical AND of the values in registers P1 and P2 and
+** write the result into register P3.
+**
+** If either P1 or P2 is 0 (false) then the result is 0 even if
+** the other input is NULL.  A NULL and true or two NULLs give
+** a NULL output.
+*/
+/* Opcode: Or P1 P2 P3 * *
+** Synopsis: r[P3]=(r[P1] || r[P2])
+**
+** Take the logical OR of the values in register P1 and P2 and
+** store the answer in register P3.
+**
+** If either P1 or P2 is nonzero (true) then the result is 1 (true)
+** even if the other input is NULL.  A NULL and false or two NULLs
+** give a NULL output.
+*/
+case OP_And:              /* same as TK_AND, in1, in2, out3 */
+case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
+  int v1;    /* Left operand:  0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+  int v2;    /* Right operand: 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+
+  v1 = sqlite3VdbeBooleanValue(&aMem[pOp->p1], 2);
+  v2 = sqlite3VdbeBooleanValue(&aMem[pOp->p2], 2);
+  if( pOp->opcode==OP_And ){
+    static const unsigned char and_logic[] = { 0, 0, 0, 0, 1, 2, 0, 2, 2 };
+    v1 = and_logic[v1*3+v2];
+  }else{
+    static const unsigned char or_logic[] = { 0, 1, 2, 1, 1, 1, 2, 1, 2 };
+    v1 = or_logic[v1*3+v2];
+  }
+  pOut = &aMem[pOp->p3];
+  if( v1==2 ){
+    MemSetTypeFlag(pOut, MEM_Null);
+  }else{
+    pOut->u.i = v1;
+    MemSetTypeFlag(pOut, MEM_Int);
+  }
+  break;
+}
+
+/* Opcode: IsTrue P1 P2 P3 P4 *
+** Synopsis: r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4
+**
+** This opcode implements the IS TRUE, IS FALSE, IS NOT TRUE, and
+** IS NOT FALSE operators.
+**
+** Interpret the value in register P1 as a boolean value.  Store that
+** boolean (a 0 or 1) in register P2.  Or if the value in register P1 is
+** NULL, then the P3 is stored in register P2.  Invert the answer if P4
+** is 1.
+**
+** The logic is summarized like this:
+**
+** <ul>
+** <li> If P3==0 and P4==0  then  r[P2] := r[P1] IS TRUE
+** <li> If P3==1 and P4==1  then  r[P2] := r[P1] IS FALSE
+** <li> If P3==0 and P4==1  then  r[P2] := r[P1] IS NOT TRUE
+** <li> If P3==1 and P4==0  then  r[P2] := r[P1] IS NOT FALSE
+** </ul>
+*/
+case OP_IsTrue: {               /* in1, out2 */
+  assert( pOp->p4type==P4_INT32 );
+  assert( pOp->p4.i==0 || pOp->p4.i==1 );
+  assert( pOp->p3==0 || pOp->p3==1 );
+  sqlite3VdbeMemSetInt64(&aMem[pOp->p2],
+      sqlite3VdbeBooleanValue(&aMem[pOp->p1], pOp->p3) ^ pOp->p4.i);
+  break;
+}
+
+/* Opcode: Not P1 P2 * * *
+** Synopsis: r[P2]= !r[P1]
+**
+** Interpret the value in register P1 as a boolean value.  Store the
+** boolean complement in register P2.  If the value in register P1 is
+** NULL, then a NULL is stored in P2.
+*/
+case OP_Not: {                /* same as TK_NOT, in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  if( (pIn1->flags & MEM_Null)==0 ){
+    sqlite3VdbeMemSetInt64(pOut, !sqlite3VdbeBooleanValue(pIn1,0));
+  }else{
+    sqlite3VdbeMemSetNull(pOut);
+  }
+  break;
+}
+
+/* Opcode: BitNot P1 P2 * * *
+** Synopsis: r[P2]= ~r[P1]
+**
+** Interpret the content of register P1 as an integer.  Store the
+** ones-complement of the P1 value into register P2.  If P1 holds
+** a NULL then store a NULL in P2.
+*/
+case OP_BitNot: {             /* same as TK_BITNOT, in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  sqlite3VdbeMemSetNull(pOut);
+  if( (pIn1->flags & MEM_Null)==0 ){
+    pOut->flags = MEM_Int;
+    pOut->u.i = ~sqlite3VdbeIntValue(pIn1);
+  }
+  break;
+}
+
+/* Opcode: Once P1 P2 * * *
+**
+** Fall through to the next instruction the first time this opcode is
+** encountered on each invocation of the byte-code program.  Jump to P2
+** on the second and all subsequent encounters during the same invocation.
+**
+** Top-level programs determine first invocation by comparing the P1
+** operand against the P1 operand on the OP_Init opcode at the beginning
+** of the program.  If the P1 values differ, then fall through and make
+** the P1 of this opcode equal to the P1 of OP_Init.  If P1 values are
+** the same then take the jump.
+**
+** For subprograms, there is a bitmask in the VdbeFrame that determines
+** whether or not the jump should be taken.  The bitmask is necessary
+** because the self-altering code trick does not work for recursive
+** triggers.
+*/
+case OP_Once: {             /* jump */
+  u32 iAddr;                /* Address of this instruction */
+  assert( p->aOp[0].opcode==OP_Init );
+  if( p->pFrame ){
+    iAddr = (int)(pOp - p->aOp);
+    if( (p->pFrame->aOnce[iAddr/8] & (1<<(iAddr & 7)))!=0 ){
+      VdbeBranchTaken(1, 2);
+      goto jump_to_p2;
+    }
+    p->pFrame->aOnce[iAddr/8] |= 1<<(iAddr & 7);
+  }else{
+    if( p->aOp[0].p1==pOp->p1 ){
+      VdbeBranchTaken(1, 2);
+      goto jump_to_p2;
+    }
+  }
+  VdbeBranchTaken(0, 2);
+  pOp->p1 = p->aOp[0].p1;
+  break;
+}
+
+/* Opcode: If P1 P2 P3 * *
+**
+** Jump to P2 if the value in register P1 is true.  The value
+** is considered true if it is numeric and non-zero.  If the value
+** in P1 is NULL then take the jump if and only if P3 is non-zero.
+*/
+case OP_If:  {               /* jump, in1 */
+  int c;
+  c = sqlite3VdbeBooleanValue(&aMem[pOp->p1], pOp->p3);
+  VdbeBranchTaken(c!=0, 2);
+  if( c ) goto jump_to_p2;
+  break;
+}
+
+/* Opcode: IfNot P1 P2 P3 * *
+**
+** Jump to P2 if the value in register P1 is False.  The value
+** is considered false if it has a numeric value of zero.  If the value
+** in P1 is NULL then take the jump if and only if P3 is non-zero.
+*/
+case OP_IfNot: {            /* jump, in1 */
+  int c;
+  c = !sqlite3VdbeBooleanValue(&aMem[pOp->p1], !pOp->p3);
+  VdbeBranchTaken(c!=0, 2);
+  if( c ) goto jump_to_p2;
+  break;
+}
+
+/* Opcode: IsNull P1 P2 * * *
+** Synopsis: if r[P1]==NULL goto P2
+**
+** Jump to P2 if the value in register P1 is NULL.
+*/
+case OP_IsNull: {            /* same as TK_ISNULL, jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  VdbeBranchTaken( (pIn1->flags & MEM_Null)!=0, 2);
+  if( (pIn1->flags & MEM_Null)!=0 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: IsType P1 P2 P3 P4 P5
+** Synopsis: if typeof(P1.P3) in P5 goto P2
+**
+** Jump to P2 if the type of a column in a btree is one of the types specified
+** by the P5 bitmask.
+**
+** P1 is normally a cursor on a btree for which the row decode cache is
+** valid through at least column P3.  In other words, there should have been
+** a prior OP_Column for column P3 or greater.  If the cursor is not valid,
+** then this opcode might give spurious results.
+** The the btree row has fewer than P3 columns, then use P4 as the
+** datatype.
+**
+** If P1 is -1, then P3 is a register number and the datatype is taken
+** from the value in that register.
+**
+** P5 is a bitmask of data types.  SQLITE_INTEGER is the least significant
+** (0x01) bit. SQLITE_FLOAT is the 0x02 bit. SQLITE_TEXT is 0x04.
+** SQLITE_BLOB is 0x08.  SQLITE_NULL is 0x10.
+**
+** WARNING: This opcode does not reliably distinguish between NULL and REAL
+** when P1>=0.  If the database contains a NaN value, this opcode will think
+** that the datatype is REAL when it should be NULL.  When P1<0 and the value
+** is already stored in register P3, then this opcode does reliably
+** distinguish between NULL and REAL.  The problem only arises then P1>=0.
+**
+** Take the jump to address P2 if and only if the datatype of the
+** value determined by P1 and P3 corresponds to one of the bits in the
+** P5 bitmask.
+**
+*/
+case OP_IsType: {        /* jump */
+  VdbeCursor *pC;
+  u16 typeMask;
+  u32 serialType;
+
+  assert( pOp->p1>=(-1) && pOp->p1<p->nCursor );
+  assert( pOp->p1>=0 || (pOp->p3>=0 && pOp->p3<=(p->nMem+1 - p->nCursor)) );
+  if( pOp->p1>=0 ){
+    pC = p->apCsr[pOp->p1];
+    assert( pC!=0 );
+    assert( pOp->p3>=0 );
+    if( pOp->p3<pC->nHdrParsed ){
+      serialType = pC->aType[pOp->p3];
+      if( serialType>=12 ){
+        if( serialType&1 ){
+          typeMask = 0x04;   /* SQLITE_TEXT */
+        }else{
+          typeMask = 0x08;   /* SQLITE_BLOB */
+        }
+      }else{
+        static const unsigned char aMask[] = {
+           0x10, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x2,
+           0x01, 0x01, 0x10, 0x10
+        };
+        testcase( serialType==0 );
+        testcase( serialType==1 );
+        testcase( serialType==2 );
+        testcase( serialType==3 );
+        testcase( serialType==4 );
+        testcase( serialType==5 );
+        testcase( serialType==6 );
+        testcase( serialType==7 );
+        testcase( serialType==8 );
+        testcase( serialType==9 );
+        testcase( serialType==10 );
+        testcase( serialType==11 );
+        typeMask = aMask[serialType];
+      }
+    }else{
+      typeMask = 1 << (pOp->p4.i - 1);
+      testcase( typeMask==0x01 );
+      testcase( typeMask==0x02 );
+      testcase( typeMask==0x04 );
+      testcase( typeMask==0x08 );
+      testcase( typeMask==0x10 );
+    }
+  }else{
+    assert( memIsValid(&aMem[pOp->p3]) );
+    typeMask = 1 << (sqlite3_value_type((sqlite3_value*)&aMem[pOp->p3])-1);
+    testcase( typeMask==0x01 );
+    testcase( typeMask==0x02 );
+    testcase( typeMask==0x04 );
+    testcase( typeMask==0x08 );
+    testcase( typeMask==0x10 );
+  }
+  VdbeBranchTaken( (typeMask & pOp->p5)!=0, 2);
+  if( typeMask & pOp->p5 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: ZeroOrNull P1 P2 P3 * *
+** Synopsis: r[P2] = 0 OR NULL
+**
+** If both registers P1 and P3 are NOT NULL, then store a zero in
+** register P2.  If either registers P1 or P3 are NULL then put
+** a NULL in register P2.
+*/
+case OP_ZeroOrNull: {            /* in1, in2, out2, in3 */
+  if( (aMem[pOp->p1].flags & MEM_Null)!=0
+   || (aMem[pOp->p3].flags & MEM_Null)!=0
+  ){
+    sqlite3VdbeMemSetNull(aMem + pOp->p2);
+  }else{
+    sqlite3VdbeMemSetInt64(aMem + pOp->p2, 0);
+  }
+  break;
+}
+
+/* Opcode: NotNull P1 P2 * * *
+** Synopsis: if r[P1]!=NULL goto P2
+**
+** Jump to P2 if the value in register P1 is not NULL.
+*/
+case OP_NotNull: {            /* same as TK_NOTNULL, jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  VdbeBranchTaken( (pIn1->flags & MEM_Null)==0, 2);
+  if( (pIn1->flags & MEM_Null)==0 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: IfNullRow P1 P2 P3 * *
+** Synopsis: if P1.nullRow then r[P3]=NULL, goto P2
+**
+** Check the cursor P1 to see if it is currently pointing at a NULL row.
+** If it is, then set register P3 to NULL and jump immediately to P2.
+** If P1 is not on a NULL row, then fall through without making any
+** changes.
+**
+** If P1 is not an open cursor, then this opcode is a no-op.
+*/
+case OP_IfNullRow: {         /* jump */
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  if( pC && pC->nullRow ){
+    sqlite3VdbeMemSetNull(aMem + pOp->p3);
+    goto jump_to_p2;
+  }
+  break;
+}
+
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+/* Opcode: Offset P1 P2 P3 * *
+** Synopsis: r[P3] = sqlite_offset(P1)
+**
+** Store in register r[P3] the byte offset into the database file that is the
+** start of the payload for the record at which that cursor P1 is currently
+** pointing.
+**
+** P2 is the column number for the argument to the sqlite_offset() function.
+** This opcode does not use P2 itself, but the P2 value is used by the
+** code generator.  The P1, P2, and P3 operands to this opcode are the
+** same as for OP_Column.
+**
+** This opcode is only available if SQLite is compiled with the
+** -DSQLITE_ENABLE_OFFSET_SQL_FUNC option.
+*/
+case OP_Offset: {          /* out3 */
+  VdbeCursor *pC;    /* The VDBE cursor */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  pOut = &p->aMem[pOp->p3];
+  if( pC==0 || pC->eCurType!=CURTYPE_BTREE ){
+    sqlite3VdbeMemSetNull(pOut);
+  }else{
+    if( pC->deferredMoveto ){
+      rc = sqlite3VdbeFinishMoveto(pC);
+      if( rc ) goto abort_due_to_error;
+    }
+    if( sqlite3BtreeEof(pC->uc.pCursor) ){
+      sqlite3VdbeMemSetNull(pOut);
+    }else{
+      sqlite3VdbeMemSetInt64(pOut, sqlite3BtreeOffset(pC->uc.pCursor));
+    }
+  }
+  break;
+}
+#endif /* SQLITE_ENABLE_OFFSET_SQL_FUNC */
+
+/* Opcode: Column P1 P2 P3 P4 P5
+** Synopsis: r[P3]=PX cursor P1 column P2
+**
+** Interpret the data that cursor P1 points to as a structure built using
+** the MakeRecord instruction.  (See the MakeRecord opcode for additional
+** information about the format of the data.)  Extract the P2-th column
+** from this record.  If there are less than (P2+1)
+** values in the record, extract a NULL.
+**
+** The value extracted is stored in register P3.
+**
+** If the record contains fewer than P2 fields, then extract a NULL.  Or,
+** if the P4 argument is a P4_MEM use the value of the P4 argument as
+** the result.
+**
+** If the OPFLAG_LENGTHARG bit is set in P5 then the result is guaranteed
+** to only be used by the length() function or the equivalent.  The content
+** of large blobs is not loaded, thus saving CPU cycles.  If the
+** OPFLAG_TYPEOFARG bit is set then the result will only be used by the
+** typeof() function or the IS NULL or IS NOT NULL operators or the
+** equivalent.  In this case, all content loading can be omitted.
+*/
+case OP_Column: {            /* ncycle */
+  u32 p2;            /* column number to retrieve */
+  VdbeCursor *pC;    /* The VDBE cursor */
+  BtCursor *pCrsr;   /* The B-Tree cursor corresponding to pC */
+  u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
+  int len;           /* The length of the serialized data for the column */
+  int i;             /* Loop counter */
+  Mem *pDest;        /* Where to write the extracted value */
+  Mem sMem;          /* For storing the record being decoded */
+  const u8 *zData;   /* Part of the record being decoded */
+  const u8 *zHdr;    /* Next unparsed byte of the header */
+  const u8 *zEndHdr; /* Pointer to first byte after the header */
+  u64 offset64;      /* 64-bit offset */
+  u32 t;             /* A type code from the record header */
+  Mem *pReg;         /* PseudoTable input register */
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  pC = p->apCsr[pOp->p1];
+  p2 = (u32)pOp->p2;
+
+op_column_restart:
+  assert( pC!=0 );
+  assert( p2<(u32)pC->nField
+       || (pC->eCurType==CURTYPE_PSEUDO && pC->seekResult==0) );
+  aOffset = pC->aOffset;
+  assert( aOffset==pC->aType+pC->nField );
+  assert( pC->eCurType!=CURTYPE_VTAB );
+  assert( pC->eCurType!=CURTYPE_PSEUDO || pC->nullRow );
+  assert( pC->eCurType!=CURTYPE_SORTER );
+
+  if( pC->cacheStatus!=p->cacheCtr ){                /*OPTIMIZATION-IF-FALSE*/
+    if( pC->nullRow ){
+      if( pC->eCurType==CURTYPE_PSEUDO && pC->seekResult>0 ){
+        /* For the special case of as pseudo-cursor, the seekResult field
+        ** identifies the register that holds the record */
+        pReg = &aMem[pC->seekResult];
+        assert( pReg->flags & MEM_Blob );
+        assert( memIsValid(pReg) );
+        pC->payloadSize = pC->szRow = pReg->n;
+        pC->aRow = (u8*)pReg->z;
+      }else{
+        pDest = &aMem[pOp->p3];
+        memAboutToChange(p, pDest);
+        sqlite3VdbeMemSetNull(pDest);
+        goto op_column_out;
+      }
+    }else{
+      pCrsr = pC->uc.pCursor;
+      if( pC->deferredMoveto ){
+        u32 iMap;
+        assert( !pC->isEphemeral );
+        if( pC->ub.aAltMap && (iMap = pC->ub.aAltMap[1+p2])>0  ){
+          pC = pC->pAltCursor;
+          p2 = iMap - 1;
+          goto op_column_restart;
+        }
+        rc = sqlite3VdbeFinishMoveto(pC);
+        if( rc ) goto abort_due_to_error;
+      }else if( sqlite3BtreeCursorHasMoved(pCrsr) ){
+        rc = sqlite3VdbeHandleMovedCursor(pC);
+        if( rc ) goto abort_due_to_error;
+        goto op_column_restart;
+      }
+      assert( pC->eCurType==CURTYPE_BTREE );
+      assert( pCrsr );
+      assert( sqlite3BtreeCursorIsValid(pCrsr) );
+      pC->payloadSize = sqlite3BtreePayloadSize(pCrsr);
+      pC->aRow = sqlite3BtreePayloadFetch(pCrsr, &pC->szRow);
+      assert( pC->szRow<=pC->payloadSize );
+      assert( pC->szRow<=65536 );  /* Maximum page size is 64KiB */
+    }
+    pC->cacheStatus = p->cacheCtr;
+    if( (aOffset[0] = pC->aRow[0])<0x80 ){
+      pC->iHdrOffset = 1;
+    }else{
+      pC->iHdrOffset = sqlite3GetVarint32(pC->aRow, aOffset);
+    }
+    pC->nHdrParsed = 0;
+
+    if( pC->szRow<aOffset[0] ){      /*OPTIMIZATION-IF-FALSE*/
+      /* pC->aRow does not have to hold the entire row, but it does at least
+      ** need to cover the header of the record.  If pC->aRow does not contain
+      ** the complete header, then set it to zero, forcing the header to be
+      ** dynamically allocated. */
+      pC->aRow = 0;
+      pC->szRow = 0;
+
+      /* Make sure a corrupt database has not given us an oversize header.
+      ** Do this now to avoid an oversize memory allocation.
+      **
+      ** Type entries can be between 1 and 5 bytes each.  But 4 and 5 byte
+      ** types use so much data space that there can only be 4096 and 32 of
+      ** them, respectively.  So the maximum header length results from a
+      ** 3-byte type for each of the maximum of 32768 columns plus three
+      ** extra bytes for the header length itself.  32768*3 + 3 = 98307.
+      */
+      if( aOffset[0] > 98307 || aOffset[0] > pC->payloadSize ){
+        goto op_column_corrupt;
+      }
+    }else{
+      /* This is an optimization.  By skipping over the first few tests
+      ** (ex: pC->nHdrParsed<=p2) in the next section, we achieve a
+      ** measurable performance gain.
+      **
+      ** This branch is taken even if aOffset[0]==0.  Such a record is never
+      ** generated by SQLite, and could be considered corruption, but we
+      ** accept it for historical reasons.  When aOffset[0]==0, the code this
+      ** branch jumps to reads past the end of the record, but never more
+      ** than a few bytes.  Even if the record occurs at the end of the page
+      ** content area, the "page header" comes after the page content and so
+      ** this overread is harmless.  Similar overreads can occur for a corrupt
+      ** database file.
+      */
+      zData = pC->aRow;
+      assert( pC->nHdrParsed<=p2 );         /* Conditional skipped */
+      testcase( aOffset[0]==0 );
+      goto op_column_read_header;
+    }
+  }else if( sqlite3BtreeCursorHasMoved(pC->uc.pCursor) ){
+    rc = sqlite3VdbeHandleMovedCursor(pC);
+    if( rc ) goto abort_due_to_error;
+    goto op_column_restart;
+  }
+
+  /* Make sure at least the first p2+1 entries of the header have been
+  ** parsed and valid information is in aOffset[] and pC->aType[].
+  */
+  if( pC->nHdrParsed<=p2 ){
+    /* If there is more header available for parsing in the record, try
+    ** to extract additional fields up through the p2+1-th field
+    */
+    if( pC->iHdrOffset<aOffset[0] ){
+      /* Make sure zData points to enough of the record to cover the header. */
+      if( pC->aRow==0 ){
+        memset(&sMem, 0, sizeof(sMem));
+        rc = sqlite3VdbeMemFromBtreeZeroOffset(pC->uc.pCursor,aOffset[0],&sMem);
+        if( rc!=SQLITE_OK ) goto abort_due_to_error;
+        zData = (u8*)sMem.z;
+      }else{
+        zData = pC->aRow;
+      }
+
+      /* Fill in pC->aType[i] and aOffset[i] values through the p2-th field. */
+    op_column_read_header:
+      i = pC->nHdrParsed;
+      offset64 = aOffset[i];
+      zHdr = zData + pC->iHdrOffset;
+      zEndHdr = zData + aOffset[0];
+      testcase( zHdr>=zEndHdr );
+      do{
+        if( (pC->aType[i] = t = zHdr[0])<0x80 ){
+          zHdr++;
+          offset64 += sqlite3VdbeOneByteSerialTypeLen(t);
+        }else{
+          zHdr += sqlite3GetVarint32(zHdr, &t);
+          pC->aType[i] = t;
+          offset64 += sqlite3VdbeSerialTypeLen(t);
+        }
+        aOffset[++i] = (u32)(offset64 & 0xffffffff);
+      }while( (u32)i<=p2 && zHdr<zEndHdr );
+
+      /* The record is corrupt if any of the following are true:
+      ** (1) the bytes of the header extend past the declared header size
+      ** (2) the entire header was used but not all data was used
+      ** (3) the end of the data extends beyond the end of the record.
+      */
+      if( (zHdr>=zEndHdr && (zHdr>zEndHdr || offset64!=pC->payloadSize))
+       || (offset64 > pC->payloadSize)
+      ){
+        if( aOffset[0]==0 ){
+          i = 0;
+          zHdr = zEndHdr;
+        }else{
+          if( pC->aRow==0 ) sqlite3VdbeMemRelease(&sMem);
+          goto op_column_corrupt;
+        }
+      }
+
+      pC->nHdrParsed = i;
+      pC->iHdrOffset = (u32)(zHdr - zData);
+      if( pC->aRow==0 ) sqlite3VdbeMemRelease(&sMem);
+    }else{
+      t = 0;
+    }
+
+    /* If after trying to extract new entries from the header, nHdrParsed is
+    ** still not up to p2, that means that the record has fewer than p2
+    ** columns.  So the result will be either the default value or a NULL.
+    */
+    if( pC->nHdrParsed<=p2 ){
+      pDest = &aMem[pOp->p3];
+      memAboutToChange(p, pDest);
+      if( pOp->p4type==P4_MEM ){
+        sqlite3VdbeMemShallowCopy(pDest, pOp->p4.pMem, MEM_Static);
+      }else{
+        sqlite3VdbeMemSetNull(pDest);
+      }
+      goto op_column_out;
+    }
+  }else{
+    t = pC->aType[p2];
+  }
+
+  /* Extract the content for the p2+1-th column.  Control can only
+  ** reach this point if aOffset[p2], aOffset[p2+1], and pC->aType[p2] are
+  ** all valid.
+  */
+  assert( p2<pC->nHdrParsed );
+  assert( rc==SQLITE_OK );
+  pDest = &aMem[pOp->p3];
+  memAboutToChange(p, pDest);
+  assert( sqlite3VdbeCheckMemInvariants(pDest) );
+  if( VdbeMemDynamic(pDest) ){
+    sqlite3VdbeMemSetNull(pDest);
+  }
+  assert( t==pC->aType[p2] );
+  if( pC->szRow>=aOffset[p2+1] ){
+    /* This is the common case where the desired content fits on the original
+    ** page - where the content is not on an overflow page */
+    zData = pC->aRow + aOffset[p2];
+    if( t<12 ){
+      sqlite3VdbeSerialGet(zData, t, pDest);
+    }else{
+      /* If the column value is a string, we need a persistent value, not
+      ** a MEM_Ephem value.  This branch is a fast short-cut that is equivalent
+      ** to calling sqlite3VdbeSerialGet() and sqlite3VdbeDeephemeralize().
+      */
+      static const u16 aFlag[] = { MEM_Blob, MEM_Str|MEM_Term };
+      pDest->n = len = (t-12)/2;
+      pDest->enc = encoding;
+      if( pDest->szMalloc < len+2 ){
+        if( len>db->aLimit[SQLITE_LIMIT_LENGTH] ) goto too_big;
+        pDest->flags = MEM_Null;
+        if( sqlite3VdbeMemGrow(pDest, len+2, 0) ) goto no_mem;
+      }else{
+        pDest->z = pDest->zMalloc;
+      }
+      memcpy(pDest->z, zData, len);
+      pDest->z[len] = 0;
+      pDest->z[len+1] = 0;
+      pDest->flags = aFlag[t&1];
+    }
+  }else{
+    u8 p5;
+    pDest->enc = encoding;
+    assert( pDest->db==db );
+    /* This branch happens only when content is on overflow pages */
+    if( ((p5 = (pOp->p5 & OPFLAG_BYTELENARG))!=0
+          && (p5==OPFLAG_TYPEOFARG
+              || (t>=12 && ((t&1)==0 || p5==OPFLAG_BYTELENARG))
+             )
+        )
+     || sqlite3VdbeSerialTypeLen(t)==0
+    ){
+      /* Content is irrelevant for
+      **    1. the typeof() function,
+      **    2. the length(X) function if X is a blob, and
+      **    3. if the content length is zero.
+      ** So we might as well use bogus content rather than reading
+      ** content from disk.
+      **
+      ** Although sqlite3VdbeSerialGet() may read at most 8 bytes from the
+      ** buffer passed to it, debugging function VdbeMemPrettyPrint() may
+      ** read more.  Use the global constant sqlite3CtypeMap[] as the array,
+      ** as that array is 256 bytes long (plenty for VdbeMemPrettyPrint())
+      ** and it begins with a bunch of zeros.
+      */
+      sqlite3VdbeSerialGet((u8*)sqlite3CtypeMap, t, pDest);
+    }else{
+      rc = vdbeColumnFromOverflow(pC, p2, t, aOffset[p2],
+                p->cacheCtr, colCacheCtr, pDest);
+      if( rc ){
+        if( rc==SQLITE_NOMEM ) goto no_mem;
+        if( rc==SQLITE_TOOBIG ) goto too_big;
+        goto abort_due_to_error;
+      }
+    }
+  }
+
+op_column_out:
+  UPDATE_MAX_BLOBSIZE(pDest);
+  REGISTER_TRACE(pOp->p3, pDest);
+  break;
+
+op_column_corrupt:
+  if( aOp[0].p3>0 ){
+    pOp = &aOp[aOp[0].p3-1];
+    break;
+  }else{
+    rc = SQLITE_CORRUPT_BKPT;
+    goto abort_due_to_error;
+  }
+}
+
+/* Opcode: TypeCheck P1 P2 P3 P4 *
+** Synopsis: typecheck(r[P1@P2])
+**
+** Apply affinities to the range of P2 registers beginning with P1.
+** Take the affinities from the Table object in P4.  If any value
+** cannot be coerced into the correct type, then raise an error.
+**
+** This opcode is similar to OP_Affinity except that this opcode
+** forces the register type to the Table column type.  This is used
+** to implement "strict affinity".
+**
+** GENERATED ALWAYS AS ... STATIC columns are only checked if P3
+** is zero.  When P3 is non-zero, no type checking occurs for
+** static generated columns.  Virtual columns are computed at query time
+** and so they are never checked.
+**
+** Preconditions:
+**
+** <ul>
+** <li> P2 should be the number of non-virtual columns in the
+**      table of P4.
+** <li> Table P4 should be a STRICT table.
+** </ul>
+**
+** If any precondition is false, an assertion fault occurs.
+*/
+case OP_TypeCheck: {
+  Table *pTab;
+  Column *aCol;
+  int i;
+
+  assert( pOp->p4type==P4_TABLE );
+  pTab = pOp->p4.pTab;
+  assert( pTab->tabFlags & TF_Strict );
+  assert( pTab->nNVCol==pOp->p2 );
+  aCol = pTab->aCol;
+  pIn1 = &aMem[pOp->p1];
+  for(i=0; i<pTab->nCol; i++){
+    if( aCol[i].colFlags & COLFLAG_GENERATED ){
+      if( aCol[i].colFlags & COLFLAG_VIRTUAL ) continue;
+      if( pOp->p3 ){ pIn1++; continue; }
+    }
+    assert( pIn1 < &aMem[pOp->p1+pOp->p2] );
+    applyAffinity(pIn1, aCol[i].affinity, encoding);
+    if( (pIn1->flags & MEM_Null)==0 ){
+      switch( aCol[i].eCType ){
+        case COLTYPE_BLOB: {
+          if( (pIn1->flags & MEM_Blob)==0 ) goto vdbe_type_error;
+          break;
+        }
+        case COLTYPE_INTEGER:
+        case COLTYPE_INT: {
+          if( (pIn1->flags & MEM_Int)==0 ) goto vdbe_type_error;
+          break;
+        }
+        case COLTYPE_TEXT: {
+          if( (pIn1->flags & MEM_Str)==0 ) goto vdbe_type_error;
+          break;
+        }
+        case COLTYPE_REAL: {
+          testcase( (pIn1->flags & (MEM_Real|MEM_IntReal))==MEM_Real );
+          assert( (pIn1->flags & MEM_IntReal)==0 );
+          if( pIn1->flags & MEM_Int ){
+            /* When applying REAL affinity, if the result is still an MEM_Int
+            ** that will fit in 6 bytes, then change the type to MEM_IntReal
+            ** so that we keep the high-resolution integer value but know that
+            ** the type really wants to be REAL. */
+            testcase( pIn1->u.i==140737488355328LL );
+            testcase( pIn1->u.i==140737488355327LL );
+            testcase( pIn1->u.i==-140737488355328LL );
+            testcase( pIn1->u.i==-140737488355329LL );
+            if( pIn1->u.i<=140737488355327LL && pIn1->u.i>=-140737488355328LL){
+              pIn1->flags |= MEM_IntReal;
+              pIn1->flags &= ~MEM_Int;
+            }else{
+              pIn1->u.r = (double)pIn1->u.i;
+              pIn1->flags |= MEM_Real;
+              pIn1->flags &= ~MEM_Int;
+            }
+          }else if( (pIn1->flags & (MEM_Real|MEM_IntReal))==0 ){
+            goto vdbe_type_error;
+          }
+          break;
+        }
+        default: {
+          /* COLTYPE_ANY.  Accept anything. */
+          break;
+        }
+      }
+    }
+    REGISTER_TRACE((int)(pIn1-aMem), pIn1);
+    pIn1++;
+  }
+  assert( pIn1 == &aMem[pOp->p1+pOp->p2] );
+  break;
+
+vdbe_type_error:
+  sqlite3VdbeError(p, "cannot store %s value in %s column %s.%s",
+     vdbeMemTypeName(pIn1), sqlite3StdType[aCol[i].eCType-1],
+     pTab->zName, aCol[i].zCnName);
+  rc = SQLITE_CONSTRAINT_DATATYPE;
+  goto abort_due_to_error;
+}
+
+/* Opcode: Affinity P1 P2 * P4 *
+** Synopsis: affinity(r[P1@P2])
+**
+** Apply affinities to a range of P2 registers starting with P1.
+**
+** P4 is a string that is P2 characters long. The N-th character of the
+** string indicates the column affinity that should be used for the N-th
+** memory cell in the range.
+*/
+case OP_Affinity: {
+  const char *zAffinity;   /* The affinity to be applied */
+
+  zAffinity = pOp->p4.z;
+  assert( zAffinity!=0 );
+  assert( pOp->p2>0 );
+  assert( zAffinity[pOp->p2]==0 );
+  pIn1 = &aMem[pOp->p1];
+  while( 1 /*exit-by-break*/ ){
+    assert( pIn1 <= &p->aMem[(p->nMem+1 - p->nCursor)] );
+    assert( zAffinity[0]==SQLITE_AFF_NONE || memIsValid(pIn1) );
+    applyAffinity(pIn1, zAffinity[0], encoding);
+    if( zAffinity[0]==SQLITE_AFF_REAL && (pIn1->flags & MEM_Int)!=0 ){
+      /* When applying REAL affinity, if the result is still an MEM_Int
+      ** that will fit in 6 bytes, then change the type to MEM_IntReal
+      ** so that we keep the high-resolution integer value but know that
+      ** the type really wants to be REAL. */
+      testcase( pIn1->u.i==140737488355328LL );
+      testcase( pIn1->u.i==140737488355327LL );
+      testcase( pIn1->u.i==-140737488355328LL );
+      testcase( pIn1->u.i==-140737488355329LL );
+      if( pIn1->u.i<=140737488355327LL && pIn1->u.i>=-140737488355328LL ){
+        pIn1->flags |= MEM_IntReal;
+        pIn1->flags &= ~MEM_Int;
+      }else{
+        pIn1->u.r = (double)pIn1->u.i;
+        pIn1->flags |= MEM_Real;
+        pIn1->flags &= ~(MEM_Int|MEM_Str);
+      }
+    }
+    REGISTER_TRACE((int)(pIn1-aMem), pIn1);
+    zAffinity++;
+    if( zAffinity[0]==0 ) break;
+    pIn1++;
+  }
+  break;
+}
+
+/* Opcode: MakeRecord P1 P2 P3 P4 *
+** Synopsis: r[P3]=mkrec(r[P1@P2])
+**
+** Convert P2 registers beginning with P1 into the [record format]
+** use as a data record in a database table or as a key
+** in an index.  The OP_Column opcode can decode the record later.
+**
+** P4 may be a string that is P2 characters long.  The N-th character of the
+** string indicates the column affinity that should be used for the N-th
+** field of the index key.
+**
+** The mapping from character to affinity is given by the SQLITE_AFF_
+** macros defined in sqliteInt.h.
+**
+** If P4 is NULL then all index fields have the affinity BLOB.
+**
+** The meaning of P5 depends on whether or not the SQLITE_ENABLE_NULL_TRIM
+** compile-time option is enabled:
+**
+**   * If SQLITE_ENABLE_NULL_TRIM is enabled, then the P5 is the index
+**     of the right-most table that can be null-trimmed.
+**
+**   * If SQLITE_ENABLE_NULL_TRIM is omitted, then P5 has the value
+**     OPFLAG_NOCHNG_MAGIC if the OP_MakeRecord opcode is allowed to
+**     accept no-change records with serial_type 10.  This value is
+**     only used inside an assert() and does not affect the end result.
+*/
+case OP_MakeRecord: {
+  Mem *pRec;             /* The new record */
+  u64 nData;             /* Number of bytes of data space */
+  int nHdr;              /* Number of bytes of header space */
+  i64 nByte;             /* Data space required for this record */
+  i64 nZero;             /* Number of zero bytes at the end of the record */
+  int nVarint;           /* Number of bytes in a varint */
+  u32 serial_type;       /* Type field */
+  Mem *pData0;           /* First field to be combined into the record */
+  Mem *pLast;            /* Last field of the record */
+  int nField;            /* Number of fields in the record */
+  char *zAffinity;       /* The affinity string for the record */
+  u32 len;               /* Length of a field */
+  u8 *zHdr;              /* Where to write next byte of the header */
+  u8 *zPayload;          /* Where to write next byte of the payload */
+
+  /* Assuming the record contains N fields, the record format looks
+  ** like this:
+  **
+  ** ------------------------------------------------------------------------
+  ** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 |
+  ** ------------------------------------------------------------------------
+  **
+  ** Data(0) is taken from register P1.  Data(1) comes from register P1+1
+  ** and so forth.
+  **
+  ** Each type field is a varint representing the serial type of the
+  ** corresponding data element (see sqlite3VdbeSerialType()). The
+  ** hdr-size field is also a varint which is the offset from the beginning
+  ** of the record to data0.
+  */
+  nData = 0;         /* Number of bytes of data space */
+  nHdr = 0;          /* Number of bytes of header space */
+  nZero = 0;         /* Number of zero bytes at the end of the record */
+  nField = pOp->p1;
+  zAffinity = pOp->p4.z;
+  assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=(p->nMem+1 - p->nCursor)+1 );
+  pData0 = &aMem[nField];
+  nField = pOp->p2;
+  pLast = &pData0[nField-1];
+
+  /* Identify the output register */
+  assert( pOp->p3<pOp->p1 || pOp->p3>=pOp->p1+pOp->p2 );
+  pOut = &aMem[pOp->p3];
+  memAboutToChange(p, pOut);
+
+  /* Apply the requested affinity to all inputs
+  */
+  assert( pData0<=pLast );
+  if( zAffinity ){
+    pRec = pData0;
+    do{
+      applyAffinity(pRec, zAffinity[0], encoding);
+      if( zAffinity[0]==SQLITE_AFF_REAL && (pRec->flags & MEM_Int) ){
+        pRec->flags |= MEM_IntReal;
+        pRec->flags &= ~(MEM_Int);
+      }
+      REGISTER_TRACE((int)(pRec-aMem), pRec);
+      zAffinity++;
+      pRec++;
+      assert( zAffinity[0]==0 || pRec<=pLast );
+    }while( zAffinity[0] );
+  }
+
+#ifdef SQLITE_ENABLE_NULL_TRIM
+  /* NULLs can be safely trimmed from the end of the record, as long as
+  ** as the schema format is 2 or more and none of the omitted columns
+  ** have a non-NULL default value.  Also, the record must be left with
+  ** at least one field.  If P5>0 then it will be one more than the
+  ** index of the right-most column with a non-NULL default value */
+  if( pOp->p5 ){
+    while( (pLast->flags & MEM_Null)!=0 && nField>pOp->p5 ){
+      pLast--;
+      nField--;
+    }
+  }
+#endif
+
+  /* Loop through the elements that will make up the record to figure
+  ** out how much space is required for the new record.  After this loop,
+  ** the Mem.uTemp field of each term should hold the serial-type that will
+  ** be used for that term in the generated record:
+  **
+  **   Mem.uTemp value    type
+  **   ---------------    ---------------
+  **      0               NULL
+  **      1               1-byte signed integer
+  **      2               2-byte signed integer
+  **      3               3-byte signed integer
+  **      4               4-byte signed integer
+  **      5               6-byte signed integer
+  **      6               8-byte signed integer
+  **      7               IEEE float
+  **      8               Integer constant 0
+  **      9               Integer constant 1
+  **     10,11            reserved for expansion
+  **    N>=12 and even    BLOB
+  **    N>=13 and odd     text
+  **
+  ** The following additional values are computed:
+  **     nHdr        Number of bytes needed for the record header
+  **     nData       Number of bytes of data space needed for the record
+  **     nZero       Zero bytes at the end of the record
+  */
+  pRec = pLast;
+  do{
+    assert( memIsValid(pRec) );
+    if( pRec->flags & MEM_Null ){
+      if( pRec->flags & MEM_Zero ){
+        /* Values with MEM_Null and MEM_Zero are created by xColumn virtual
+        ** table methods that never invoke sqlite3_result_xxxxx() while
+        ** computing an unchanging column value in an UPDATE statement.
+        ** Give such values a special internal-use-only serial-type of 10
+        ** so that they can be passed through to xUpdate and have
+        ** a true sqlite3_value_nochange(). */
+#ifndef SQLITE_ENABLE_NULL_TRIM
+        assert( pOp->p5==OPFLAG_NOCHNG_MAGIC || CORRUPT_DB );
+#endif
+        pRec->uTemp = 10;
+      }else{
+        pRec->uTemp = 0;
+      }
+      nHdr++;
+    }else if( pRec->flags & (MEM_Int|MEM_IntReal) ){
+      /* Figure out whether to use 1, 2, 4, 6 or 8 bytes. */
+      i64 i = pRec->u.i;
+      u64 uu;
+      testcase( pRec->flags & MEM_Int );
+      testcase( pRec->flags & MEM_IntReal );
+      if( i<0 ){
+        uu = ~i;
+      }else{
+        uu = i;
+      }
+      nHdr++;
+      testcase( uu==127 );               testcase( uu==128 );
+      testcase( uu==32767 );             testcase( uu==32768 );
+      testcase( uu==8388607 );           testcase( uu==8388608 );
+      testcase( uu==2147483647 );        testcase( uu==2147483648LL );
+      testcase( uu==140737488355327LL ); testcase( uu==140737488355328LL );
+      if( uu<=127 ){
+        if( (i&1)==i && p->minWriteFileFormat>=4 ){
+          pRec->uTemp = 8+(u32)uu;
+        }else{
+          nData++;
+          pRec->uTemp = 1;
+        }
+      }else if( uu<=32767 ){
+        nData += 2;
+        pRec->uTemp = 2;
+      }else if( uu<=8388607 ){
+        nData += 3;
+        pRec->uTemp = 3;
+      }else if( uu<=2147483647 ){
+        nData += 4;
+        pRec->uTemp = 4;
+      }else if( uu<=140737488355327LL ){
+        nData += 6;
+        pRec->uTemp = 5;
+      }else{
+        nData += 8;
+        if( pRec->flags & MEM_IntReal ){
+          /* If the value is IntReal and is going to take up 8 bytes to store
+          ** as an integer, then we might as well make it an 8-byte floating
+          ** point value */
+          pRec->u.r = (double)pRec->u.i;
+          pRec->flags &= ~MEM_IntReal;
+          pRec->flags |= MEM_Real;
+          pRec->uTemp = 7;
+        }else{
+          pRec->uTemp = 6;
+        }
+      }
+    }else if( pRec->flags & MEM_Real ){
+      nHdr++;
+      nData += 8;
+      pRec->uTemp = 7;
+    }else{
+      assert( db->mallocFailed || pRec->flags&(MEM_Str|MEM_Blob) );
+      assert( pRec->n>=0 );
+      len = (u32)pRec->n;
+      serial_type = (len*2) + 12 + ((pRec->flags & MEM_Str)!=0);
+      if( pRec->flags & MEM_Zero ){
+        serial_type += pRec->u.nZero*2;
+        if( nData ){
+          if( sqlite3VdbeMemExpandBlob(pRec) ) goto no_mem;
+          len += pRec->u.nZero;
+        }else{
+          nZero += pRec->u.nZero;
+        }
+      }
+      nData += len;
+      nHdr += sqlite3VarintLen(serial_type);
+      pRec->uTemp = serial_type;
+    }
+    if( pRec==pData0 ) break;
+    pRec--;
+  }while(1);
+
+  /* EVIDENCE-OF: R-22564-11647 The header begins with a single varint
+  ** which determines the total number of bytes in the header. The varint
+  ** value is the size of the header in bytes including the size varint
+  ** itself. */
+  testcase( nHdr==126 );
+  testcase( nHdr==127 );
+  if( nHdr<=126 ){
+    /* The common case */
+    nHdr += 1;
+  }else{
+    /* Rare case of a really large header */
+    nVarint = sqlite3VarintLen(nHdr);
+    nHdr += nVarint;
+    if( nVarint<sqlite3VarintLen(nHdr) ) nHdr++;
+  }
+  nByte = nHdr+nData;
+
+  /* Make sure the output register has a buffer large enough to store
+  ** the new record. The output register (pOp->p3) is not allowed to
+  ** be one of the input registers (because the following call to
+  ** sqlite3VdbeMemClearAndResize() could clobber the value before it is used).
+  */
+  if( nByte+nZero<=pOut->szMalloc ){
+    /* The output register is already large enough to hold the record.
+    ** No error checks or buffer enlargement is required */
+    pOut->z = pOut->zMalloc;
+  }else{
+    /* Need to make sure that the output is not too big and then enlarge
+    ** the output register to hold the full result */
+    if( nByte+nZero>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+      goto too_big;
+    }
+    if( sqlite3VdbeMemClearAndResize(pOut, (int)nByte) ){
+      goto no_mem;
+    }
+  }
+  pOut->n = (int)nByte;
+  pOut->flags = MEM_Blob;
+  if( nZero ){
+    pOut->u.nZero = nZero;
+    pOut->flags |= MEM_Zero;
+  }
+  UPDATE_MAX_BLOBSIZE(pOut);
+  zHdr = (u8 *)pOut->z;
+  zPayload = zHdr + nHdr;
+
+  /* Write the record */
+  if( nHdr<0x80 ){
+    *(zHdr++) = nHdr;
+  }else{
+    zHdr += sqlite3PutVarint(zHdr,nHdr);
+  }
+  assert( pData0<=pLast );
+  pRec = pData0;
+  while( 1 /*exit-by-break*/ ){
+    serial_type = pRec->uTemp;
+    /* EVIDENCE-OF: R-06529-47362 Following the size varint are one or more
+    ** additional varints, one per column.
+    ** EVIDENCE-OF: R-64536-51728 The values for each column in the record
+    ** immediately follow the header. */
+    if( serial_type<=7 ){
+      *(zHdr++) = serial_type;
+      if( serial_type==0 ){
+        /* NULL value.  No change in zPayload */
+      }else{
+        u64 v;
+        if( serial_type==7 ){
+          assert( sizeof(v)==sizeof(pRec->u.r) );
+          memcpy(&v, &pRec->u.r, sizeof(v));
+          swapMixedEndianFloat(v);
+        }else{
+          v = pRec->u.i;
+        }
+        len = sqlite3SmallTypeSizes[serial_type];
+        assert( len>=1 && len<=8 && len!=5 && len!=7 );
+        switch( len ){
+          default: zPayload[7] = (u8)(v&0xff); v >>= 8;
+                   zPayload[6] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 6:  zPayload[5] = (u8)(v&0xff); v >>= 8;
+                   zPayload[4] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 4:  zPayload[3] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 3:  zPayload[2] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 2:  zPayload[1] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 1:  zPayload[0] = (u8)(v&0xff);
+        }
+        zPayload += len;
+      }
+    }else if( serial_type<0x80 ){
+      *(zHdr++) = serial_type;
+      if( serial_type>=14 && pRec->n>0 ){
+        assert( pRec->z!=0 );
+        memcpy(zPayload, pRec->z, pRec->n);
+        zPayload += pRec->n;
+      }
+    }else{
+      zHdr += sqlite3PutVarint(zHdr, serial_type);
+      if( pRec->n ){
+        assert( pRec->z!=0 );
+        assert( pRec->z!=(const char*)sqlite3CtypeMap );
+        memcpy(zPayload, pRec->z, pRec->n);
+        zPayload += pRec->n;
+      }
+    }
+    if( pRec==pLast ) break;
+    pRec++;
+  }
+  assert( nHdr==(int)(zHdr - (u8*)pOut->z) );
+  assert( nByte==(int)(zPayload - (u8*)pOut->z) );
+
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  REGISTER_TRACE(pOp->p3, pOut);
+  break;
+}
+
+/* Opcode: Count P1 P2 P3 * *
+** Synopsis: r[P2]=count()
+**
+** Store the number of entries (an integer value) in the table or index
+** opened by cursor P1 in register P2.
+**
+** If P3==0, then an exact count is obtained, which involves visiting
+** every btree page of the table.  But if P3 is non-zero, an estimate
+** is returned based on the current cursor position.
+*/
+case OP_Count: {         /* out2 */
+  i64 nEntry;
+  BtCursor *pCrsr;
+
+  assert( p->apCsr[pOp->p1]->eCurType==CURTYPE_BTREE );
+  pCrsr = p->apCsr[pOp->p1]->uc.pCursor;
+  assert( pCrsr );
+  if( pOp->p3 ){
+    nEntry = sqlite3BtreeRowCountEst(pCrsr);
+  }else{
+    nEntry = 0;  /* Not needed.  Only used to silence a warning. */
+    rc = sqlite3BtreeCount(db, pCrsr, &nEntry);
+    if( rc ) goto abort_due_to_error;
+  }
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = nEntry;
+  goto check_for_interrupt;
+}
+
+/* Opcode: Savepoint P1 * * P4 *
+**
+** Open, release or rollback the savepoint named by parameter P4, depending
+** on the value of P1. To open a new savepoint set P1==0 (SAVEPOINT_BEGIN).
+** To release (commit) an existing savepoint set P1==1 (SAVEPOINT_RELEASE).
+** To rollback an existing savepoint set P1==2 (SAVEPOINT_ROLLBACK).
+*/
+case OP_Savepoint: {
+  int p1;                         /* Value of P1 operand */
+  char *zName;                    /* Name of savepoint */
+  int nName;
+  Savepoint *pNew;
+  Savepoint *pSavepoint;
+  Savepoint *pTmp;
+  int iSavepoint;
+  int ii;
+
+  p1 = pOp->p1;
+  zName = pOp->p4.z;
+
+  /* Assert that the p1 parameter is valid. Also that if there is no open
+  ** transaction, then there cannot be any savepoints.
+  */
+  assert( db->pSavepoint==0 || db->autoCommit==0 );
+  assert( p1==SAVEPOINT_BEGIN||p1==SAVEPOINT_RELEASE||p1==SAVEPOINT_ROLLBACK );
+  assert( db->pSavepoint || db->isTransactionSavepoint==0 );
+  assert( checkSavepointCount(db) );
+  assert( p->bIsReader );
+
+  if( p1==SAVEPOINT_BEGIN ){
+    if( db->nVdbeWrite>0 ){
+      /* A new savepoint cannot be created if there are active write
+      ** statements (i.e. open read/write incremental blob handles).
+      */
+      sqlite3VdbeError(p, "cannot open savepoint - SQL statements in progress");
+      rc = SQLITE_BUSY;
+    }else{
+      nName = sqlite3Strlen30(zName);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      /* This call is Ok even if this savepoint is actually a transaction
+      ** savepoint (and therefore should not prompt xSavepoint()) callbacks.
+      ** If this is a transaction savepoint being opened, it is guaranteed
+      ** that the db->aVTrans[] array is empty.  */
+      assert( db->autoCommit==0 || db->nVTrans==0 );
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN,
+                                db->nStatement+db->nSavepoint);
+      if( rc!=SQLITE_OK ) goto abort_due_to_error;
+#endif
+
+      /* Create a new savepoint structure. */
+      pNew = sqlite3DbMallocRawNN(db, sizeof(Savepoint)+nName+1);
+      if( pNew ){
+        pNew->zName = (char *)&pNew[1];
+        memcpy(pNew->zName, zName, nName+1);
+
+        /* If there is no open transaction, then mark this as a special
+        ** "transaction savepoint". */
+        if( db->autoCommit ){
+          db->autoCommit = 0;
+          db->isTransactionSavepoint = 1;
+        }else{
+          db->nSavepoint++;
+        }
+
+        /* Link the new savepoint into the database handle's list. */
+        pNew->pNext = db->pSavepoint;
+        db->pSavepoint = pNew;
+        pNew->nDeferredCons = db->nDeferredCons;
+        pNew->nDeferredImmCons = db->nDeferredImmCons;
+      }
+    }
+  }else{
+    assert( p1==SAVEPOINT_RELEASE || p1==SAVEPOINT_ROLLBACK );
+    iSavepoint = 0;
+
+    /* Find the named savepoint. If there is no such savepoint, then an
+    ** an error is returned to the user.  */
+    for(
+      pSavepoint = db->pSavepoint;
+      pSavepoint && sqlite3StrICmp(pSavepoint->zName, zName);
+      pSavepoint = pSavepoint->pNext
+    ){
+      iSavepoint++;
+    }
+    if( !pSavepoint ){
+      sqlite3VdbeError(p, "no such savepoint: %s", zName);
+      rc = SQLITE_ERROR;
+    }else if( db->nVdbeWrite>0 && p1==SAVEPOINT_RELEASE ){
+      /* It is not possible to release (commit) a savepoint if there are
+      ** active write statements.
+      */
+      sqlite3VdbeError(p, "cannot release savepoint - "
+                          "SQL statements in progress");
+      rc = SQLITE_BUSY;
+    }else{
+
+      /* Determine whether or not this is a transaction savepoint. If so,
+      ** and this is a RELEASE command, then the current transaction
+      ** is committed.
+      */
+      int isTransaction = pSavepoint->pNext==0 && db->isTransactionSavepoint;
+      if( isTransaction && p1==SAVEPOINT_RELEASE ){
+        if( (rc = sqlite3VdbeCheckFk(p, 1))!=SQLITE_OK ){
+          goto vdbe_return;
+        }
+        db->autoCommit = 1;
+        if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
+          p->pc = (int)(pOp - aOp);
+          db->autoCommit = 0;
+          p->rc = rc = SQLITE_BUSY;
+          goto vdbe_return;
+        }
+        rc = p->rc;
+        if( rc ){
+          db->autoCommit = 0;
+        }else{
+          db->isTransactionSavepoint = 0;
+        }
+      }else{
+        int isSchemaChange;
+        iSavepoint = db->nSavepoint - iSavepoint - 1;
+        if( p1==SAVEPOINT_ROLLBACK ){
+          isSchemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0;
+          for(ii=0; ii<db->nDb; ii++){
+            rc = sqlite3BtreeTripAllCursors(db->aDb[ii].pBt,
+                                       SQLITE_ABORT_ROLLBACK,
+                                       isSchemaChange==0);
+            if( rc!=SQLITE_OK ) goto abort_due_to_error;
+          }
+        }else{
+          assert( p1==SAVEPOINT_RELEASE );
+          isSchemaChange = 0;
+        }
+        for(ii=0; ii<db->nDb; ii++){
+          rc = sqlite3BtreeSavepoint(db->aDb[ii].pBt, p1, iSavepoint);
+          if( rc!=SQLITE_OK ){
+            goto abort_due_to_error;
+          }
+        }
+        if( isSchemaChange ){
+          sqlite3ExpirePreparedStatements(db, 0);
+          sqlite3ResetAllSchemasOfConnection(db);
+          db->mDbFlags |= DBFLAG_SchemaChange;
+        }
+      }
+      if( rc ) goto abort_due_to_error;
+
+      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all
+      ** savepoints nested inside of the savepoint being operated on. */
+      while( db->pSavepoint!=pSavepoint ){
+        pTmp = db->pSavepoint;
+        db->pSavepoint = pTmp->pNext;
+        sqlite3DbFree(db, pTmp);
+        db->nSavepoint--;
+      }
+
+      /* If it is a RELEASE, then destroy the savepoint being operated on
+      ** too. If it is a ROLLBACK TO, then set the number of deferred
+      ** constraint violations present in the database to the value stored
+      ** when the savepoint was created.  */
+      if( p1==SAVEPOINT_RELEASE ){
+        assert( pSavepoint==db->pSavepoint );
+        db->pSavepoint = pSavepoint->pNext;
+        sqlite3DbFree(db, pSavepoint);
+        if( !isTransaction ){
+          db->nSavepoint--;
+        }
+      }else{
+        assert( p1==SAVEPOINT_ROLLBACK );
+        db->nDeferredCons = pSavepoint->nDeferredCons;
+        db->nDeferredImmCons = pSavepoint->nDeferredImmCons;
+      }
+
+      if( !isTransaction || p1==SAVEPOINT_ROLLBACK ){
+        rc = sqlite3VtabSavepoint(db, p1, iSavepoint);
+        if( rc!=SQLITE_OK ) goto abort_due_to_error;
+      }
+    }
+  }
+  if( rc ) goto abort_due_to_error;
+  if( p->eVdbeState==VDBE_HALT_STATE ){
+    rc = SQLITE_DONE;
+    goto vdbe_return;
+  }
+  break;
+}
+
+/* Opcode: AutoCommit P1 P2 * * *
+**
+** Set the database auto-commit flag to P1 (1 or 0). If P2 is true, roll
+** back any currently active btree transactions. If there are any active
+** VMs (apart from this one), then a ROLLBACK fails.  A COMMIT fails if
+** there are active writing VMs or active VMs that use shared cache.
+**
+** This instruction causes the VM to halt.
+*/
+case OP_AutoCommit: {
+  int desiredAutoCommit;
+  int iRollback;
+
+  desiredAutoCommit = pOp->p1;
+  iRollback = pOp->p2;
+  assert( desiredAutoCommit==1 || desiredAutoCommit==0 );
+  assert( desiredAutoCommit==1 || iRollback==0 );
+  assert( db->nVdbeActive>0 );  /* At least this one VM is active */
+  assert( p->bIsReader );
+
+  if( desiredAutoCommit!=db->autoCommit ){
+    if( iRollback ){
+      assert( desiredAutoCommit==1 );
+      sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
+      db->autoCommit = 1;
+    }else if( desiredAutoCommit && db->nVdbeWrite>0 ){
+      /* If this instruction implements a COMMIT and other VMs are writing
+      ** return an error indicating that the other VMs must complete first.
+      */
+      sqlite3VdbeError(p, "cannot commit transaction - "
+                          "SQL statements in progress");
+      rc = SQLITE_BUSY;
+      goto abort_due_to_error;
+    }else if( (rc = sqlite3VdbeCheckFk(p, 1))!=SQLITE_OK ){
+      goto vdbe_return;
+    }else{
+      db->autoCommit = (u8)desiredAutoCommit;
+    }
+    if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
+      p->pc = (int)(pOp - aOp);
+      db->autoCommit = (u8)(1-desiredAutoCommit);
+      p->rc = rc = SQLITE_BUSY;
+      goto vdbe_return;
+    }
+    sqlite3CloseSavepoints(db);
+    if( p->rc==SQLITE_OK ){
+      rc = SQLITE_DONE;
+    }else{
+      rc = SQLITE_ERROR;
+    }
+    goto vdbe_return;
+  }else{
+    sqlite3VdbeError(p,
+        (!desiredAutoCommit)?"cannot start a transaction within a transaction":(
+        (iRollback)?"cannot rollback - no transaction is active":
+                   "cannot commit - no transaction is active"));
+
+    rc = SQLITE_ERROR;
+    goto abort_due_to_error;
+  }
+  /*NOTREACHED*/ assert(0);
+}
+
+/* Opcode: Transaction P1 P2 P3 P4 P5
+**
+** Begin a transaction on database P1 if a transaction is not already
+** active.
+** If P2 is non-zero, then a write-transaction is started, or if a
+** read-transaction is already active, it is upgraded to a write-transaction.
+** If P2 is zero, then a read-transaction is started.  If P2 is 2 or more
+** then an exclusive transaction is started.
+**
+** P1 is the index of the database file on which the transaction is
+** started.  Index 0 is the main database file and index 1 is the
+** file used for temporary tables.  Indices of 2 or more are used for
+** attached databases.
+**
+** If a write-transaction is started and the Vdbe.usesStmtJournal flag is
+** true (this flag is set if the Vdbe may modify more than one row and may
+** throw an ABORT exception), a statement transaction may also be opened.
+** More specifically, a statement transaction is opened iff the database
+** connection is currently not in autocommit mode, or if there are other
+** active statements. A statement transaction allows the changes made by this
+** VDBE to be rolled back after an error without having to roll back the
+** entire transaction. If no error is encountered, the statement transaction
+** will automatically commit when the VDBE halts.
+**
+** If P5!=0 then this opcode also checks the schema cookie against P3
+** and the schema generation counter against P4.
+** The cookie changes its value whenever the database schema changes.
+** This operation is used to detect when that the cookie has changed
+** and that the current process needs to reread the schema.  If the schema
+** cookie in P3 differs from the schema cookie in the database header or
+** if the schema generation counter in P4 differs from the current
+** generation counter, then an SQLITE_SCHEMA error is raised and execution
+** halts.  The sqlite3_step() wrapper function might then reprepare the
+** statement and rerun it from the beginning.
+*/
+case OP_Transaction: {
+  Btree *pBt;
+  Db *pDb;
+  int iMeta = 0;
+
+  assert( p->bIsReader );
+  assert( p->readOnly==0 || pOp->p2==0 );
+  assert( pOp->p2>=0 && pOp->p2<=2 );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p1) );
+  assert( rc==SQLITE_OK );
+  if( pOp->p2 && (db->flags & (SQLITE_QueryOnly|SQLITE_CorruptRdOnly))!=0 ){
+    if( db->flags & SQLITE_QueryOnly ){
+      /* Writes prohibited by the "PRAGMA query_only=TRUE" statement */
+      rc = SQLITE_READONLY;
+    }else{
+      /* Writes prohibited due to a prior SQLITE_CORRUPT in the current
+      ** transaction */
+      rc = SQLITE_CORRUPT;
+    }
+    goto abort_due_to_error;
+  }
+  pDb = &db->aDb[pOp->p1];
+  pBt = pDb->pBt;
+
+  if( pBt ){
+    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2, &iMeta);
+    testcase( rc==SQLITE_BUSY_SNAPSHOT );
+    testcase( rc==SQLITE_BUSY_RECOVERY );
+    if( rc!=SQLITE_OK ){
+      if( (rc&0xff)==SQLITE_BUSY ){
+        p->pc = (int)(pOp - aOp);
+        p->rc = rc;
+        goto vdbe_return;
+      }
+      goto abort_due_to_error;
+    }
+
+    if( p->usesStmtJournal
+     && pOp->p2
+     && (db->autoCommit==0 || db->nVdbeRead>1)
+    ){
+      assert( sqlite3BtreeTxnState(pBt)==SQLITE_TXN_WRITE );
+      if( p->iStatement==0 ){
+        assert( db->nStatement>=0 && db->nSavepoint>=0 );
+        db->nStatement++;
+        p->iStatement = db->nSavepoint + db->nStatement;
+      }
+
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN, p->iStatement-1);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3BtreeBeginStmt(pBt, p->iStatement);
+      }
+
+      /* Store the current value of the database handles deferred constraint
+      ** counter. If the statement transaction needs to be rolled back,
+      ** the value of this counter needs to be restored too.  */
+      p->nStmtDefCons = db->nDeferredCons;
+      p->nStmtDefImmCons = db->nDeferredImmCons;
+    }
+  }
+  assert( pOp->p5==0 || pOp->p4type==P4_INT32 );
+  if( rc==SQLITE_OK
+   && pOp->p5
+   && (iMeta!=pOp->p3 || pDb->pSchema->iGeneration!=pOp->p4.i)
+  ){
+    /*
+    ** IMPLEMENTATION-OF: R-03189-51135 As each SQL statement runs, the schema
+    ** version is checked to ensure that the schema has not changed since the
+    ** SQL statement was prepared.
+    */
+    sqlite3DbFree(db, p->zErrMsg);
+    p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
+    /* If the schema-cookie from the database file matches the cookie
+    ** stored with the in-memory representation of the schema, do
+    ** not reload the schema from the database file.
+    **
+    ** If virtual-tables are in use, this is not just an optimization.
+    ** Often, v-tables store their data in other SQLite tables, which
+    ** are queried from within xNext() and other v-table methods using
+    ** prepared queries. If such a query is out-of-date, we do not want to
+    ** discard the database schema, as the user code implementing the
+    ** v-table would have to be ready for the sqlite3_vtab structure itself
+    ** to be invalidated whenever sqlite3_step() is called from within
+    ** a v-table method.
+    */
+    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
+      sqlite3ResetOneSchema(db, pOp->p1);
+    }
+    p->expired = 1;
+    rc = SQLITE_SCHEMA;
+
+    /* Set changeCntOn to 0 to prevent the value returned by sqlite3_changes()
+    ** from being modified in sqlite3VdbeHalt(). If this statement is
+    ** reprepared, changeCntOn will be set again. */
+    p->changeCntOn = 0;
+  }
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: ReadCookie P1 P2 P3 * *
+**
+** Read cookie number P3 from database P1 and write it into register P2.
+** P3==1 is the schema version.  P3==2 is the database format.
+** P3==3 is the recommended pager cache size, and so forth.  P1==0 is
+** the main database file and P1==1 is the database file used to store
+** temporary tables.
+**
+** There must be a read-lock on the database (either a transaction
+** must be started or there must be an open cursor) before
+** executing this instruction.
+*/
+case OP_ReadCookie: {               /* out2 */
+  int iMeta;
+  int iDb;
+  int iCookie;
+
+  assert( p->bIsReader );
+  iDb = pOp->p1;
+  iCookie = pOp->p3;
+  assert( pOp->p3<SQLITE_N_BTREE_META );
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( db->aDb[iDb].pBt!=0 );
+  assert( DbMaskTest(p->btreeMask, iDb) );
+
+  sqlite3BtreeGetMeta(db->aDb[iDb].pBt, iCookie, (u32 *)&iMeta);
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = iMeta;
+  break;
+}
+
+/* Opcode: SetCookie P1 P2 P3 * P5
+**
+** Write the integer value P3 into cookie number P2 of database P1.
+** P2==1 is the schema version.  P2==2 is the database format.
+** P2==3 is the recommended pager cache
+** size, and so forth.  P1==0 is the main database file and P1==1 is the
+** database file used to store temporary tables.
+**
+** A transaction must be started before executing this opcode.
+**
+** If P2 is the SCHEMA_VERSION cookie (cookie number 1) then the internal
+** schema version is set to P3-P5.  The "PRAGMA schema_version=N" statement
+** has P5 set to 1, so that the internal schema version will be different
+** from the database schema version, resulting in a schema reset.
+*/
+case OP_SetCookie: {
+  Db *pDb;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  assert( pOp->p2<SQLITE_N_BTREE_META );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p1) );
+  assert( p->readOnly==0 );
+  pDb = &db->aDb[pOp->p1];
+  assert( pDb->pBt!=0 );
+  assert( sqlite3SchemaMutexHeld(db, pOp->p1, 0) );
+  /* See note about index shifting on OP_ReadCookie */
+  rc = sqlite3BtreeUpdateMeta(pDb->pBt, pOp->p2, pOp->p3);
+  if( pOp->p2==BTREE_SCHEMA_VERSION ){
+    /* When the schema cookie changes, record the new cookie internally */
+    *(u32*)&pDb->pSchema->schema_cookie = *(u32*)&pOp->p3 - pOp->p5;
+    db->mDbFlags |= DBFLAG_SchemaChange;
+    sqlite3FkClearTriggerCache(db, pOp->p1);
+  }else if( pOp->p2==BTREE_FILE_FORMAT ){
+    /* Record changes in the file format */
+    pDb->pSchema->file_format = pOp->p3;
+  }
+  if( pOp->p1==1 ){
+    /* Invalidate all prepared statements whenever the TEMP database
+    ** schema is changed.  Ticket #1644 */
+    sqlite3ExpirePreparedStatements(db, 0);
+    p->expired = 0;
+  }
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: OpenRead P1 P2 P3 P4 P5
+** Synopsis: root=P2 iDb=P3
+**
+** Open a read-only cursor for the database table whose root page is
+** P2 in a database file.  The database file is determined by P3.
+** P3==0 means the main database, P3==1 means the database used for
+** temporary tables, and P3>1 means used the corresponding attached
+** database.  Give the new cursor an identifier of P1.  The P1
+** values need not be contiguous but all P1 values should be small integers.
+** It is an error for P1 to be negative.
+**
+** Allowed P5 bits:
+** <ul>
+** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
+**       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
+**       of OP_SeekLE/OP_IdxLT)
+** </ul>
+**
+** The P4 value may be either an integer (P4_INT32) or a pointer to
+** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo
+** object, then table being opened must be an [index b-tree] where the
+** KeyInfo object defines the content and collating
+** sequence of that index b-tree. Otherwise, if P4 is an integer
+** value, then the table being opened must be a [table b-tree] with a
+** number of columns no less than the value of P4.
+**
+** See also: OpenWrite, ReopenIdx
+*/
+/* Opcode: ReopenIdx P1 P2 P3 P4 P5
+** Synopsis: root=P2 iDb=P3
+**
+** The ReopenIdx opcode works like OP_OpenRead except that it first
+** checks to see if the cursor on P1 is already open on the same
+** b-tree and if it is this opcode becomes a no-op.  In other words,
+** if the cursor is already open, do not reopen it.
+**
+** The ReopenIdx opcode may only be used with P5==0 or P5==OPFLAG_SEEKEQ
+** and with P4 being a P4_KEYINFO object.  Furthermore, the P3 value must
+** be the same as every other ReopenIdx or OpenRead for the same cursor
+** number.
+**
+** Allowed P5 bits:
+** <ul>
+** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
+**       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
+**       of OP_SeekLE/OP_IdxLT)
+** </ul>
+**
+** See also: OP_OpenRead, OP_OpenWrite
+*/
+/* Opcode: OpenWrite P1 P2 P3 P4 P5
+** Synopsis: root=P2 iDb=P3
+**
+** Open a read/write cursor named P1 on the table or index whose root
+** page is P2 (or whose root page is held in register P2 if the
+** OPFLAG_P2ISREG bit is set in P5 - see below).
+**
+** The P4 value may be either an integer (P4_INT32) or a pointer to
+** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo
+** object, then table being opened must be an [index b-tree] where the
+** KeyInfo object defines the content and collating
+** sequence of that index b-tree. Otherwise, if P4 is an integer
+** value, then the table being opened must be a [table b-tree] with a
+** number of columns no less than the value of P4.
+**
+** Allowed P5 bits:
+** <ul>
+** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
+**       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
+**       of OP_SeekLE/OP_IdxLT)
+** <li>  <b>0x08 OPFLAG_FORDELETE</b>: This cursor is used only to seek
+**       and subsequently delete entries in an index btree.  This is a
+**       hint to the storage engine that the storage engine is allowed to
+**       ignore.  The hint is not used by the official SQLite b*tree storage
+**       engine, but is used by COMDB2.
+** <li>  <b>0x10 OPFLAG_P2ISREG</b>: Use the content of register P2
+**       as the root page, not the value of P2 itself.
+** </ul>
+**
+** This instruction works like OpenRead except that it opens the cursor
+** in read/write mode.
+**
+** See also: OP_OpenRead, OP_ReopenIdx
+*/
+case OP_ReopenIdx: {         /* ncycle */
+  int nField;
+  KeyInfo *pKeyInfo;
+  u32 p2;
+  int iDb;
+  int wrFlag;
+  Btree *pX;
+  VdbeCursor *pCur;
+  Db *pDb;
+
+  assert( pOp->p5==0 || pOp->p5==OPFLAG_SEEKEQ );
+  assert( pOp->p4type==P4_KEYINFO );
+  pCur = p->apCsr[pOp->p1];
+  if( pCur && pCur->pgnoRoot==(u32)pOp->p2 ){
+    assert( pCur->iDb==pOp->p3 );      /* Guaranteed by the code generator */
+    assert( pCur->eCurType==CURTYPE_BTREE );
+    sqlite3BtreeClearCursor(pCur->uc.pCursor);
+    goto open_cursor_set_hints;
+  }
+  /* If the cursor is not currently open or is open on a different
+  ** index, then fall through into OP_OpenRead to force a reopen */
+case OP_OpenRead:            /* ncycle */
+case OP_OpenWrite:
+
+  assert( pOp->opcode==OP_OpenWrite || pOp->p5==0 || pOp->p5==OPFLAG_SEEKEQ );
+  assert( p->bIsReader );
+  assert( pOp->opcode==OP_OpenRead || pOp->opcode==OP_ReopenIdx
+          || p->readOnly==0 );
+
+  if( p->expired==1 ){
+    rc = SQLITE_ABORT_ROLLBACK;
+    goto abort_due_to_error;
+  }
+
+  nField = 0;
+  pKeyInfo = 0;
+  p2 = (u32)pOp->p2;
+  iDb = pOp->p3;
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( DbMaskTest(p->btreeMask, iDb) );
+  pDb = &db->aDb[iDb];
+  pX = pDb->pBt;
+  assert( pX!=0 );
+  if( pOp->opcode==OP_OpenWrite ){
+    assert( OPFLAG_FORDELETE==BTREE_FORDELETE );
+    wrFlag = BTREE_WRCSR | (pOp->p5 & OPFLAG_FORDELETE);
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( pDb->pSchema->file_format < p->minWriteFileFormat ){
+      p->minWriteFileFormat = pDb->pSchema->file_format;
+    }
+    if( pOp->p5 & OPFLAG_P2ISREG ){
+      assert( p2>0 );
+      assert( p2<=(u32)(p->nMem+1 - p->nCursor) );
+      pIn2 = &aMem[p2];
+      assert( memIsValid(pIn2) );
+      assert( (pIn2->flags & MEM_Int)!=0 );
+      sqlite3VdbeMemIntegerify(pIn2);
+      p2 = (int)pIn2->u.i;
+      /* The p2 value always comes from a prior OP_CreateBtree opcode and
+      ** that opcode will always set the p2 value to 2 or more or else fail.
+      ** If there were a failure, the prepared statement would have halted
+      ** before reaching this instruction. */
+      assert( p2>=2 );
+    }
+  }else{
+    wrFlag = 0;
+    assert( (pOp->p5 & OPFLAG_P2ISREG)==0 );
+  }
+  if( pOp->p4type==P4_KEYINFO ){
+    pKeyInfo = pOp->p4.pKeyInfo;
+    assert( pKeyInfo->enc==ENC(db) );
+    assert( pKeyInfo->db==db );
+    nField = pKeyInfo->nAllField;
+  }else if( pOp->p4type==P4_INT32 ){
+    nField = pOp->p4.i;
+  }
+  assert( pOp->p1>=0 );
+  assert( nField>=0 );
+  testcase( nField==0 );  /* Table with INTEGER PRIMARY KEY and nothing else */
+  pCur = allocateCursor(p, pOp->p1, nField, CURTYPE_BTREE);
+  if( pCur==0 ) goto no_mem;
+  pCur->iDb = iDb;
+  pCur->nullRow = 1;
+  pCur->isOrdered = 1;
+  pCur->pgnoRoot = p2;
+#ifdef SQLITE_DEBUG
+  pCur->wrFlag = wrFlag;
+#endif
+  rc = sqlite3BtreeCursor(pX, p2, wrFlag, pKeyInfo, pCur->uc.pCursor);
+  pCur->pKeyInfo = pKeyInfo;
+  /* Set the VdbeCursor.isTable variable. Previous versions of
+  ** SQLite used to check if the root-page flags were sane at this point
+  ** and report database corruption if they were not, but this check has
+  ** since moved into the btree layer.  */
+  pCur->isTable = pOp->p4type!=P4_KEYINFO;
+
+open_cursor_set_hints:
+  assert( OPFLAG_BULKCSR==BTREE_BULKLOAD );
+  assert( OPFLAG_SEEKEQ==BTREE_SEEK_EQ );
+  testcase( pOp->p5 & OPFLAG_BULKCSR );
+  testcase( pOp->p2 & OPFLAG_SEEKEQ );
+  sqlite3BtreeCursorHintFlags(pCur->uc.pCursor,
+                               (pOp->p5 & (OPFLAG_BULKCSR|OPFLAG_SEEKEQ)));
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: OpenDup P1 P2 * * *
+**
+** Open a new cursor P1 that points to the same ephemeral table as
+** cursor P2.  The P2 cursor must have been opened by a prior OP_OpenEphemeral
+** opcode.  Only ephemeral cursors may be duplicated.
+**
+** Duplicate ephemeral cursors are used for self-joins of materialized views.
+*/
+case OP_OpenDup: {           /* ncycle */
+  VdbeCursor *pOrig;    /* The original cursor to be duplicated */
+  VdbeCursor *pCx;      /* The new cursor */
+
+  pOrig = p->apCsr[pOp->p2];
+  assert( pOrig );
+  assert( pOrig->isEphemeral );  /* Only ephemeral cursors can be duplicated */
+
+  pCx = allocateCursor(p, pOp->p1, pOrig->nField, CURTYPE_BTREE);
+  if( pCx==0 ) goto no_mem;
+  pCx->nullRow = 1;
+  pCx->isEphemeral = 1;
+  pCx->pKeyInfo = pOrig->pKeyInfo;
+  pCx->isTable = pOrig->isTable;
+  pCx->pgnoRoot = pOrig->pgnoRoot;
+  pCx->isOrdered = pOrig->isOrdered;
+  pCx->ub.pBtx = pOrig->ub.pBtx;
+  pCx->noReuse = 1;
+  pOrig->noReuse = 1;
+  rc = sqlite3BtreeCursor(pCx->ub.pBtx, pCx->pgnoRoot, BTREE_WRCSR,
+                          pCx->pKeyInfo, pCx->uc.pCursor);
+  /* The sqlite3BtreeCursor() routine can only fail for the first cursor
+  ** opened for a database.  Since there is already an open cursor when this
+  ** opcode is run, the sqlite3BtreeCursor() cannot fail */
+  assert( rc==SQLITE_OK );
+  break;
+}
+
+
+/* Opcode: OpenEphemeral P1 P2 P3 P4 P5
+** Synopsis: nColumn=P2
+**
+** Open a new cursor P1 to a transient table.
+** The cursor is always opened read/write even if
+** the main database is read-only.  The ephemeral
+** table is deleted automatically when the cursor is closed.
+**
+** If the cursor P1 is already opened on an ephemeral table, the table
+** is cleared (all content is erased).
+**
+** P2 is the number of columns in the ephemeral table.
+** The cursor points to a BTree table if P4==0 and to a BTree index
+** if P4 is not 0.  If P4 is not NULL, it points to a KeyInfo structure
+** that defines the format of keys in the index.
+**
+** The P5 parameter can be a mask of the BTREE_* flags defined
+** in btree.h.  These flags control aspects of the operation of
+** the btree.  The BTREE_OMIT_JOURNAL and BTREE_SINGLE flags are
+** added automatically.
+**
+** If P3 is positive, then reg[P3] is modified slightly so that it
+** can be used as zero-length data for OP_Insert.  This is an optimization
+** that avoids an extra OP_Blob opcode to initialize that register.
+*/
+/* Opcode: OpenAutoindex P1 P2 * P4 *
+** Synopsis: nColumn=P2
+**
+** This opcode works the same as OP_OpenEphemeral.  It has a
+** different name to distinguish its use.  Tables created using
+** by this opcode will be used for automatically created transient
+** indices in joins.
+*/
+case OP_OpenAutoindex:       /* ncycle */
+case OP_OpenEphemeral: {     /* ncycle */
+  VdbeCursor *pCx;
+  KeyInfo *pKeyInfo;
+
+  static const int vfsFlags =
+      SQLITE_OPEN_READWRITE |
+      SQLITE_OPEN_CREATE |
+      SQLITE_OPEN_EXCLUSIVE |
+      SQLITE_OPEN_DELETEONCLOSE |
+      SQLITE_OPEN_TRANSIENT_DB;
+  assert( pOp->p1>=0 );
+  assert( pOp->p2>=0 );
+  if( pOp->p3>0 ){
+    /* Make register reg[P3] into a value that can be used as the data
+    ** form sqlite3BtreeInsert() where the length of the data is zero. */
+    assert( pOp->p2==0 ); /* Only used when number of columns is zero */
+    assert( pOp->opcode==OP_OpenEphemeral );
+    assert( aMem[pOp->p3].flags & MEM_Null );
+    aMem[pOp->p3].n = 0;
+    aMem[pOp->p3].z = "";
+  }
+  pCx = p->apCsr[pOp->p1];
+  if( pCx && !pCx->noReuse &&  ALWAYS(pOp->p2<=pCx->nField) ){
+    /* If the ephemeral table is already open and has no duplicates from
+    ** OP_OpenDup, then erase all existing content so that the table is
+    ** empty again, rather than creating a new table. */
+    assert( pCx->isEphemeral );
+    pCx->seqCount = 0;
+    pCx->cacheStatus = CACHE_STALE;
+    rc = sqlite3BtreeClearTable(pCx->ub.pBtx, pCx->pgnoRoot, 0);
+  }else{
+    pCx = allocateCursor(p, pOp->p1, pOp->p2, CURTYPE_BTREE);
+    if( pCx==0 ) goto no_mem;
+    pCx->isEphemeral = 1;
+    rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pCx->ub.pBtx,
+                          BTREE_OMIT_JOURNAL | BTREE_SINGLE | pOp->p5,
+                          vfsFlags);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3BtreeBeginTrans(pCx->ub.pBtx, 1, 0);
+      if( rc==SQLITE_OK ){
+        /* If a transient index is required, create it by calling
+        ** sqlite3BtreeCreateTable() with the BTREE_BLOBKEY flag before
+        ** opening it. If a transient table is required, just use the
+        ** automatically created table with root-page 1 (an BLOB_INTKEY table).
+        */
+        if( (pCx->pKeyInfo = pKeyInfo = pOp->p4.pKeyInfo)!=0 ){
+          assert( pOp->p4type==P4_KEYINFO );
+          rc = sqlite3BtreeCreateTable(pCx->ub.pBtx, &pCx->pgnoRoot,
+              BTREE_BLOBKEY | pOp->p5);
+          if( rc==SQLITE_OK ){
+            assert( pCx->pgnoRoot==SCHEMA_ROOT+1 );
+            assert( pKeyInfo->db==db );
+            assert( pKeyInfo->enc==ENC(db) );
+            rc = sqlite3BtreeCursor(pCx->ub.pBtx, pCx->pgnoRoot, BTREE_WRCSR,
+                pKeyInfo, pCx->uc.pCursor);
+          }
+          pCx->isTable = 0;
+        }else{
+          pCx->pgnoRoot = SCHEMA_ROOT;
+          rc = sqlite3BtreeCursor(pCx->ub.pBtx, SCHEMA_ROOT, BTREE_WRCSR,
+              0, pCx->uc.pCursor);
+          pCx->isTable = 1;
+        }
+      }
+      pCx->isOrdered = (pOp->p5!=BTREE_UNORDERED);
+      assert( p->apCsr[pOp->p1]==pCx );
+      if( rc ){
+        assert( !sqlite3BtreeClosesWithCursor(pCx->ub.pBtx, pCx->uc.pCursor) );
+        sqlite3BtreeClose(pCx->ub.pBtx);
+        p->apCsr[pOp->p1] = 0;  /* Not required; helps with static analysis */
+      }else{
+        assert( sqlite3BtreeClosesWithCursor(pCx->ub.pBtx, pCx->uc.pCursor) );
+      }
+    }
+  }
+  if( rc ) goto abort_due_to_error;
+  pCx->nullRow = 1;
+  break;
+}
+
+/* Opcode: SorterOpen P1 P2 P3 P4 *
+**
+** This opcode works like OP_OpenEphemeral except that it opens
+** a transient index that is specifically designed to sort large
+** tables using an external merge-sort algorithm.
+**
+** If argument P3 is non-zero, then it indicates that the sorter may
+** assume that a stable sort considering the first P3 fields of each
+** key is sufficient to produce the required results.
+*/
+case OP_SorterOpen: {
+  VdbeCursor *pCx;
+
+  assert( pOp->p1>=0 );
+  assert( pOp->p2>=0 );
+  pCx = allocateCursor(p, pOp->p1, pOp->p2, CURTYPE_SORTER);
+  if( pCx==0 ) goto no_mem;
+  pCx->pKeyInfo = pOp->p4.pKeyInfo;
+  assert( pCx->pKeyInfo->db==db );
+  assert( pCx->pKeyInfo->enc==ENC(db) );
+  rc = sqlite3VdbeSorterInit(db, pOp->p3, pCx);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: SequenceTest P1 P2 * * *
+** Synopsis: if( cursor[P1].ctr++ ) pc = P2
+**
+** P1 is a sorter cursor. If the sequence counter is currently zero, jump
+** to P2. Regardless of whether or not the jump is taken, increment the
+** the sequence value.
+*/
+case OP_SequenceTest: {
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( isSorter(pC) );
+  if( (pC->seqCount++)==0 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: OpenPseudo P1 P2 P3 * *
+** Synopsis: P3 columns in r[P2]
+**
+** Open a new cursor that points to a fake table that contains a single
+** row of data.  The content of that one row is the content of memory
+** register P2.  In other words, cursor P1 becomes an alias for the
+** MEM_Blob content contained in register P2.
+**
+** A pseudo-table created by this opcode is used to hold a single
+** row output from the sorter so that the row can be decomposed into
+** individual columns using the OP_Column opcode.  The OP_Column opcode
+** is the only cursor opcode that works with a pseudo-table.
+**
+** P3 is the number of fields in the records that will be stored by
+** the pseudo-table.  If P2 is 0 or negative then the pseudo-cursor
+** will return NULL for every column.
+*/
+case OP_OpenPseudo: {
+  VdbeCursor *pCx;
+
+  assert( pOp->p1>=0 );
+  assert( pOp->p3>=0 );
+  pCx = allocateCursor(p, pOp->p1, pOp->p3, CURTYPE_PSEUDO);
+  if( pCx==0 ) goto no_mem;
+  pCx->nullRow = 1;
+  pCx->seekResult = pOp->p2;
+  pCx->isTable = 1;
+  /* Give this pseudo-cursor a fake BtCursor pointer so that pCx
+  ** can be safely passed to sqlite3VdbeCursorMoveto().  This avoids a test
+  ** for pCx->eCurType==CURTYPE_BTREE inside of sqlite3VdbeCursorMoveto()
+  ** which is a performance optimization */
+  pCx->uc.pCursor = sqlite3BtreeFakeValidCursor();
+  assert( pOp->p5==0 );
+  break;
+}
+
+/* Opcode: Close P1 * * * *
+**
+** Close a cursor previously opened as P1.  If P1 is not
+** currently open, this instruction is a no-op.
+*/
+case OP_Close: {             /* ncycle */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  sqlite3VdbeFreeCursor(p, p->apCsr[pOp->p1]);
+  p->apCsr[pOp->p1] = 0;
+  break;
+}
+
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+/* Opcode: ColumnsUsed P1 * * P4 *
+**
+** This opcode (which only exists if SQLite was compiled with
+** SQLITE_ENABLE_COLUMN_USED_MASK) identifies which columns of the
+** table or index for cursor P1 are used.  P4 is a 64-bit integer
+** (P4_INT64) in which the first 63 bits are one for each of the
+** first 63 columns of the table or index that are actually used
+** by the cursor.  The high-order bit is set if any column after
+** the 64th is used.
+*/
+case OP_ColumnsUsed: {
+  VdbeCursor *pC;
+  pC = p->apCsr[pOp->p1];
+  assert( pC->eCurType==CURTYPE_BTREE );
+  pC->maskUsed = *(u64*)pOp->p4.pI64;
+  break;
+}
+#endif
+
+/* Opcode: SeekGE P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
+** use the value in register P3 as the key.  If cursor P1 refers
+** to an SQL index, then P3 is the first in an array of P4 registers
+** that are used as an unpacked index key.
+**
+** Reposition cursor P1 so that  it points to the smallest entry that
+** is greater than or equal to the key value. If there are no records
+** greater than or equal to the key and P2 is not zero, then jump to P2.
+**
+** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
+** opcode will either land on a record that exactly matches the key, or
+** else it will cause a jump to P2.  When the cursor is OPFLAG_SEEKEQ,
+** this opcode must be followed by an IdxLE opcode with the same arguments.
+** The IdxGT opcode will be skipped if this opcode succeeds, but the
+** IdxGT opcode will be used on subsequent loop iterations.  The
+** OPFLAG_SEEKEQ flags is a hint to the btree layer to say that this
+** is an equality search.
+**
+** This opcode leaves the cursor configured to move in forward order,
+** from the beginning toward the end.  In other words, the cursor is
+** configured to use Next, not Prev.
+**
+** See also: Found, NotFound, SeekLt, SeekGt, SeekLe
+*/
+/* Opcode: SeekGT P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
+** use the value in register P3 as a key. If cursor P1 refers
+** to an SQL index, then P3 is the first in an array of P4 registers
+** that are used as an unpacked index key.
+**
+** Reposition cursor P1 so that it points to the smallest entry that
+** is greater than the key value. If there are no records greater than
+** the key and P2 is not zero, then jump to P2.
+**
+** This opcode leaves the cursor configured to move in forward order,
+** from the beginning toward the end.  In other words, the cursor is
+** configured to use Next, not Prev.
+**
+** See also: Found, NotFound, SeekLt, SeekGe, SeekLe
+*/
+/* Opcode: SeekLT P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
+** use the value in register P3 as a key. If cursor P1 refers
+** to an SQL index, then P3 is the first in an array of P4 registers
+** that are used as an unpacked index key.
+**
+** Reposition cursor P1 so that  it points to the largest entry that
+** is less than the key value. If there are no records less than
+** the key and P2 is not zero, then jump to P2.
+**
+** This opcode leaves the cursor configured to move in reverse order,
+** from the end toward the beginning.  In other words, the cursor is
+** configured to use Prev, not Next.
+**
+** See also: Found, NotFound, SeekGt, SeekGe, SeekLe
+*/
+/* Opcode: SeekLE P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
+** use the value in register P3 as a key. If cursor P1 refers
+** to an SQL index, then P3 is the first in an array of P4 registers
+** that are used as an unpacked index key.
+**
+** Reposition cursor P1 so that it points to the largest entry that
+** is less than or equal to the key value. If there are no records
+** less than or equal to the key and P2 is not zero, then jump to P2.
+**
+** This opcode leaves the cursor configured to move in reverse order,
+** from the end toward the beginning.  In other words, the cursor is
+** configured to use Prev, not Next.
+**
+** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
+** opcode will either land on a record that exactly matches the key, or
+** else it will cause a jump to P2.  When the cursor is OPFLAG_SEEKEQ,
+** this opcode must be followed by an IdxLE opcode with the same arguments.
+** The IdxGE opcode will be skipped if this opcode succeeds, but the
+** IdxGE opcode will be used on subsequent loop iterations.  The
+** OPFLAG_SEEKEQ flags is a hint to the btree layer to say that this
+** is an equality search.
+**
+** See also: Found, NotFound, SeekGt, SeekGe, SeekLt
+*/
+case OP_SeekLT:         /* jump0, in3, group, ncycle */
+case OP_SeekLE:         /* jump0, in3, group, ncycle */
+case OP_SeekGE:         /* jump0, in3, group, ncycle */
+case OP_SeekGT: {       /* jump0, in3, group, ncycle */
+  int res;           /* Comparison result */
+  int oc;            /* Opcode */
+  VdbeCursor *pC;    /* The cursor to seek */
+  UnpackedRecord r;  /* The key to seek for */
+  int nField;        /* Number of columns or fields in the key */
+  i64 iKey;          /* The rowid we are to seek to */
+  int eqOnly;        /* Only interested in == results */
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p2!=0 );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( OP_SeekLE == OP_SeekLT+1 );
+  assert( OP_SeekGE == OP_SeekLT+2 );
+  assert( OP_SeekGT == OP_SeekLT+3 );
+  assert( pC->isOrdered );
+  assert( pC->uc.pCursor!=0 );
+  oc = pOp->opcode;
+  eqOnly = 0;
+  pC->nullRow = 0;
+#ifdef SQLITE_DEBUG
+  pC->seekOp = pOp->opcode;
+#endif
+
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+  if( pC->isTable ){
+    u16 flags3, newType;
+    /* The OPFLAG_SEEKEQ/BTREE_SEEK_EQ flag is only set on index cursors */
+    assert( sqlite3BtreeCursorHasHint(pC->uc.pCursor, BTREE_SEEK_EQ)==0
+              || CORRUPT_DB );
+
+    /* The input value in P3 might be of any type: integer, real, string,
+    ** blob, or NULL.  But it needs to be an integer before we can do
+    ** the seek, so convert it. */
+    pIn3 = &aMem[pOp->p3];
+    flags3 = pIn3->flags;
+    if( (flags3 & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Str))==MEM_Str ){
+      applyNumericAffinity(pIn3, 0);
+    }
+    iKey = sqlite3VdbeIntValue(pIn3); /* Get the integer key value */
+    newType = pIn3->flags; /* Record the type after applying numeric affinity */
+    pIn3->flags = flags3;  /* But convert the type back to its original */
+
+    /* If the P3 value could not be converted into an integer without
+    ** loss of information, then special processing is required... */
+    if( (newType & (MEM_Int|MEM_IntReal))==0 ){
+      int c;
+      if( (newType & MEM_Real)==0 ){
+        if( (newType & MEM_Null) || oc>=OP_SeekGE ){
+          VdbeBranchTaken(1,2);
+          goto jump_to_p2;
+        }else{
+          rc = sqlite3BtreeLast(pC->uc.pCursor, &res);
+          if( rc!=SQLITE_OK ) goto abort_due_to_error;
+          goto seek_not_found;
+        }
+      }
+      c = sqlite3IntFloatCompare(iKey, pIn3->u.r);
+
+      /* If the approximation iKey is larger than the actual real search
+      ** term, substitute >= for > and < for <=. e.g. if the search term
+      ** is 4.9 and the integer approximation 5:
+      **
+      **        (x >  4.9)    ->     (x >= 5)
+      **        (x <= 4.9)    ->     (x <  5)
+      */
+      if( c>0 ){
+        assert( OP_SeekGE==(OP_SeekGT-1) );
+        assert( OP_SeekLT==(OP_SeekLE-1) );
+        assert( (OP_SeekLE & 0x0001)==(OP_SeekGT & 0x0001) );
+        if( (oc & 0x0001)==(OP_SeekGT & 0x0001) ) oc--;
+      }
+
+      /* If the approximation iKey is smaller than the actual real search
+      ** term, substitute <= for < and > for >=.  */
+      else if( c<0 ){
+        assert( OP_SeekLE==(OP_SeekLT+1) );
+        assert( OP_SeekGT==(OP_SeekGE+1) );
+        assert( (OP_SeekLT & 0x0001)==(OP_SeekGE & 0x0001) );
+        if( (oc & 0x0001)==(OP_SeekLT & 0x0001) ) oc++;
+      }
+    }
+    rc = sqlite3BtreeTableMoveto(pC->uc.pCursor, (u64)iKey, 0, &res);
+    pC->movetoTarget = iKey;  /* Used by OP_Delete */
+    if( rc!=SQLITE_OK ){
+      goto abort_due_to_error;
+    }
+  }else{
+    /* For a cursor with the OPFLAG_SEEKEQ/BTREE_SEEK_EQ hint, only the
+    ** OP_SeekGE and OP_SeekLE opcodes are allowed, and these must be
+    ** immediately followed by an OP_IdxGT or OP_IdxLT opcode, respectively,
+    ** with the same key.
+    */
+    if( sqlite3BtreeCursorHasHint(pC->uc.pCursor, BTREE_SEEK_EQ) ){
+      eqOnly = 1;
+      assert( pOp->opcode==OP_SeekGE || pOp->opcode==OP_SeekLE );
+      assert( pOp[1].opcode==OP_IdxLT || pOp[1].opcode==OP_IdxGT );
+      assert( pOp->opcode==OP_SeekGE || pOp[1].opcode==OP_IdxLT );
+      assert( pOp->opcode==OP_SeekLE || pOp[1].opcode==OP_IdxGT );
+      assert( pOp[1].p1==pOp[0].p1 );
+      assert( pOp[1].p2==pOp[0].p2 );
+      assert( pOp[1].p3==pOp[0].p3 );
+      assert( pOp[1].p4.i==pOp[0].p4.i );
+    }
+
+    nField = pOp->p4.i;
+    assert( pOp->p4type==P4_INT32 );
+    assert( nField>0 );
+    r.pKeyInfo = pC->pKeyInfo;
+    r.nField = (u16)nField;
+
+    /* The next line of code computes as follows, only faster:
+    **   if( oc==OP_SeekGT || oc==OP_SeekLE ){
+    **     r.default_rc = -1;
+    **   }else{
+    **     r.default_rc = +1;
+    **   }
+    */
+    r.default_rc = ((1 & (oc - OP_SeekLT)) ? -1 : +1);
+    assert( oc!=OP_SeekGT || r.default_rc==-1 );
+    assert( oc!=OP_SeekLE || r.default_rc==-1 );
+    assert( oc!=OP_SeekGE || r.default_rc==+1 );
+    assert( oc!=OP_SeekLT || r.default_rc==+1 );
+
+    r.aMem = &aMem[pOp->p3];
+#ifdef SQLITE_DEBUG
+    {
+      int i;
+      for(i=0; i<r.nField; i++){
+        assert( memIsValid(&r.aMem[i]) );
+        if( i>0 ) REGISTER_TRACE(pOp->p3+i, &r.aMem[i]);
+      }
+    }
+#endif
+    r.eqSeen = 0;
+    rc = sqlite3BtreeIndexMoveto(pC->uc.pCursor, &r, &res);
+    if( rc!=SQLITE_OK ){
+      goto abort_due_to_error;
+    }
+    if( eqOnly && r.eqSeen==0 ){
+      assert( res!=0 );
+      goto seek_not_found;
+    }
+  }
+#ifdef SQLITE_TEST
+  sqlite3_search_count++;
+#endif
+  if( oc>=OP_SeekGE ){  assert( oc==OP_SeekGE || oc==OP_SeekGT );
+    if( res<0 || (res==0 && oc==OP_SeekGT) ){
+      res = 0;
+      rc = sqlite3BtreeNext(pC->uc.pCursor, 0);
+      if( rc!=SQLITE_OK ){
+        if( rc==SQLITE_DONE ){
+          rc = SQLITE_OK;
+          res = 1;
+        }else{
+          goto abort_due_to_error;
+        }
+      }
+    }else{
+      res = 0;
+    }
+  }else{
+    assert( oc==OP_SeekLT || oc==OP_SeekLE );
+    if( res>0 || (res==0 && oc==OP_SeekLT) ){
+      res = 0;
+      rc = sqlite3BtreePrevious(pC->uc.pCursor, 0);
+      if( rc!=SQLITE_OK ){
+        if( rc==SQLITE_DONE ){
+          rc = SQLITE_OK;
+          res = 1;
+        }else{
+          goto abort_due_to_error;
+        }
+      }
+    }else{
+      /* res might be negative because the table is empty.  Check to
+      ** see if this is the case.
+      */
+      res = sqlite3BtreeEof(pC->uc.pCursor);
+    }
+  }
+seek_not_found:
+  assert( pOp->p2>0 );
+  VdbeBranchTaken(res!=0,2);
+  if( res ){
+    goto jump_to_p2;
+  }else if( eqOnly ){
+    assert( pOp[1].opcode==OP_IdxLT || pOp[1].opcode==OP_IdxGT );
+    pOp++; /* Skip the OP_IdxLt or OP_IdxGT that follows */
+  }
+  break;
+}
+
+
+/* Opcode: SeekScan  P1 P2 * * P5
+** Synopsis: Scan-ahead up to P1 rows
+**
+** This opcode is a prefix opcode to OP_SeekGE.  In other words, this
+** opcode must be immediately followed by OP_SeekGE. This constraint is
+** checked by assert() statements.
+**
+** This opcode uses the P1 through P4 operands of the subsequent
+** OP_SeekGE.  In the text that follows, the operands of the subsequent
+** OP_SeekGE opcode are denoted as SeekOP.P1 through SeekOP.P4.   Only
+** the P1, P2 and P5 operands of this opcode are also used, and  are called
+** This.P1, This.P2 and This.P5.
+**
+** This opcode helps to optimize IN operators on a multi-column index
+** where the IN operator is on the later terms of the index by avoiding
+** unnecessary seeks on the btree, substituting steps to the next row
+** of the b-tree instead.  A correct answer is obtained if this opcode
+** is omitted or is a no-op.
+**
+** The SeekGE.P3 and SeekGE.P4 operands identify an unpacked key which
+** is the desired entry that we want the cursor SeekGE.P1 to be pointing
+** to.  Call this SeekGE.P3/P4 row the "target".
+**
+** If the SeekGE.P1 cursor is not currently pointing to a valid row,
+** then this opcode is a no-op and control passes through into the OP_SeekGE.
+**
+** If the SeekGE.P1 cursor is pointing to a valid row, then that row
+** might be the target row, or it might be near and slightly before the
+** target row, or it might be after the target row.  If the cursor is
+** currently before the target row, then this opcode attempts to position
+** the cursor on or after the target row by invoking sqlite3BtreeStep()
+** on the cursor between 1 and This.P1 times.
+**
+** The This.P5 parameter is a flag that indicates what to do if the
+** cursor ends up pointing at a valid row that is past the target
+** row.  If This.P5 is false (0) then a jump is made to SeekGE.P2.  If
+** This.P5 is true (non-zero) then a jump is made to This.P2.  The P5==0
+** case occurs when there are no inequality constraints to the right of
+** the IN constraint.  The jump to SeekGE.P2 ends the loop.  The P5!=0 case
+** occurs when there are inequality constraints to the right of the IN
+** operator.  In that case, the This.P2 will point either directly to or
+** to setup code prior to the OP_IdxGT or OP_IdxGE opcode that checks for
+** loop terminate.
+**
+** Possible outcomes from this opcode:<ol>
+**
+** <li> If the cursor is initially not pointed to any valid row, then
+**      fall through into the subsequent OP_SeekGE opcode.
+**
+** <li> If the cursor is left pointing to a row that is before the target
+**      row, even after making as many as This.P1 calls to
+**      sqlite3BtreeNext(), then also fall through into OP_SeekGE.
+**
+** <li> If the cursor is left pointing at the target row, either because it
+**      was at the target row to begin with or because one or more
+**      sqlite3BtreeNext() calls moved the cursor to the target row,
+**      then jump to This.P2..,
+**
+** <li> If the cursor started out before the target row and a call to
+**      to sqlite3BtreeNext() moved the cursor off the end of the index
+**      (indicating that the target row definitely does not exist in the
+**      btree) then jump to SeekGE.P2, ending the loop.
+**
+** <li> If the cursor ends up on a valid row that is past the target row
+**      (indicating that the target row does not exist in the btree) then
+**      jump to SeekOP.P2 if This.P5==0 or to This.P2 if This.P5>0.
+** </ol>
+*/
+case OP_SeekScan: {          /* ncycle */
+  VdbeCursor *pC;
+  int res;
+  int nStep;
+  UnpackedRecord r;
+
+  assert( pOp[1].opcode==OP_SeekGE );
+
+  /* If pOp->p5 is clear, then pOp->p2 points to the first instruction past the
+  ** OP_IdxGT that follows the OP_SeekGE. Otherwise, it points to the first
+  ** opcode past the OP_SeekGE itself.  */
+  assert( pOp->p2>=(int)(pOp-aOp)+2 );
+#ifdef SQLITE_DEBUG
+  if( pOp->p5==0 ){
+    /* There are no inequality constraints following the IN constraint. */
+    assert( pOp[1].p1==aOp[pOp->p2-1].p1 );
+    assert( pOp[1].p2==aOp[pOp->p2-1].p2 );
+    assert( pOp[1].p3==aOp[pOp->p2-1].p3 );
+    assert( aOp[pOp->p2-1].opcode==OP_IdxGT
+         || aOp[pOp->p2-1].opcode==OP_IdxGE );
+    testcase( aOp[pOp->p2-1].opcode==OP_IdxGE );
+  }else{
+    /* There are inequality constraints.  */
+    assert( pOp->p2==(int)(pOp-aOp)+2 );
+    assert( aOp[pOp->p2-1].opcode==OP_SeekGE );
+  }
+#endif
+
+  assert( pOp->p1>0 );
+  pC = p->apCsr[pOp[1].p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( !pC->isTable );
+  if( !sqlite3BtreeCursorIsValidNN(pC->uc.pCursor) ){
+#ifdef SQLITE_DEBUG
+     if( db->flags&SQLITE_VdbeTrace ){
+       printf("... cursor not valid - fall through\n");
+     }
+#endif
+    break;
+  }
+  nStep = pOp->p1;
+  assert( nStep>=1 );
+  r.pKeyInfo = pC->pKeyInfo;
+  r.nField = (u16)pOp[1].p4.i;
+  r.default_rc = 0;
+  r.aMem = &aMem[pOp[1].p3];
+#ifdef SQLITE_DEBUG
+  {
+    int i;
+    for(i=0; i<r.nField; i++){
+      assert( memIsValid(&r.aMem[i]) );
+      REGISTER_TRACE(pOp[1].p3+i, &aMem[pOp[1].p3+i]);
+    }
+  }
+#endif
+  res = 0;  /* Not needed.  Only used to silence a warning. */
+  while(1){
+    rc = sqlite3VdbeIdxKeyCompare(db, pC, &r, &res);
+    if( rc ) goto abort_due_to_error;
+    if( res>0 && pOp->p5==0 ){
+      seekscan_search_fail:
+      /* Jump to SeekGE.P2, ending the loop */
+#ifdef SQLITE_DEBUG
+      if( db->flags&SQLITE_VdbeTrace ){
+        printf("... %d steps and then skip\n", pOp->p1 - nStep);
+      }
+#endif
+      VdbeBranchTaken(1,3);
+      pOp++;
+      goto jump_to_p2;
+    }
+    if( res>=0 ){
+      /* Jump to This.P2, bypassing the OP_SeekGE opcode */
+#ifdef SQLITE_DEBUG
+      if( db->flags&SQLITE_VdbeTrace ){
+        printf("... %d steps and then success\n", pOp->p1 - nStep);
+      }
+#endif
+      VdbeBranchTaken(2,3);
+      goto jump_to_p2;
+      break;
+    }
+    if( nStep<=0 ){
+#ifdef SQLITE_DEBUG
+      if( db->flags&SQLITE_VdbeTrace ){
+        printf("... fall through after %d steps\n", pOp->p1);
+      }
+#endif
+      VdbeBranchTaken(0,3);
+      break;
+    }
+    nStep--;
+    pC->cacheStatus = CACHE_STALE;
+    rc = sqlite3BtreeNext(pC->uc.pCursor, 0);
+    if( rc ){
+      if( rc==SQLITE_DONE ){
+        rc = SQLITE_OK;
+        goto seekscan_search_fail;
+      }else{
+        goto abort_due_to_error;
+      }
+    }
+  }
+
+  break;
+}
+
+
+/* Opcode: SeekHit P1 P2 P3 * *
+** Synopsis: set P2<=seekHit<=P3
+**
+** Increase or decrease the seekHit value for cursor P1, if necessary,
+** so that it is no less than P2 and no greater than P3.
+**
+** The seekHit integer represents the maximum of terms in an index for which
+** there is known to be at least one match.  If the seekHit value is smaller
+** than the total number of equality terms in an index lookup, then the
+** OP_IfNoHope opcode might run to see if the IN loop can be abandoned
+** early, thus saving work.  This is part of the IN-early-out optimization.
+**
+** P1 must be a valid b-tree cursor.
+*/
+case OP_SeekHit: {           /* ncycle */
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pOp->p3>=pOp->p2 );
+  if( pC->seekHit<pOp->p2 ){
+#ifdef SQLITE_DEBUG
+    if( db->flags&SQLITE_VdbeTrace ){
+      printf("seekHit changes from %d to %d\n", pC->seekHit, pOp->p2);
+    }
+#endif
+    pC->seekHit = pOp->p2;
+  }else if( pC->seekHit>pOp->p3 ){
+#ifdef SQLITE_DEBUG
+    if( db->flags&SQLITE_VdbeTrace ){
+      printf("seekHit changes from %d to %d\n", pC->seekHit, pOp->p3);
+    }
+#endif
+    pC->seekHit = pOp->p3;
+  }
+  break;
+}
+
+/* Opcode: IfNotOpen P1 P2 * * *
+** Synopsis: if( !csr[P1] ) goto P2
+**
+** If cursor P1 is not open or if P1 is set to a NULL row using the
+** OP_NullRow opcode, then jump to instruction P2. Otherwise, fall through.
+*/
+case OP_IfNotOpen: {        /* jump */
+  VdbeCursor *pCur;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pCur = p->apCsr[pOp->p1];
+  VdbeBranchTaken(pCur==0 || pCur->nullRow, 2);
+  if( pCur==0 || pCur->nullRow ){
+    goto jump_to_p2_and_check_for_interrupt;
+  }
+  break;
+}
+
+/* Opcode: Found P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
+**
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** is a prefix of any entry in P1 then a jump is made to P2 and
+** P1 is left pointing at the matching entry.
+**
+** This operation leaves the cursor in a state where it can be
+** advanced in the forward direction.  The Next instruction will work,
+** but not the Prev instruction.
+**
+** See also: NotFound, NoConflict, NotExists. SeekGe
+*/
+/* Opcode: NotFound P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
+**
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** is not the prefix of any entry in P1 then a jump is made to P2.  If P1
+** does contain an entry whose prefix matches the P3/P4 record then control
+** falls through to the next instruction and P1 is left pointing at the
+** matching entry.
+**
+** This operation leaves the cursor in a state where it cannot be
+** advanced in either direction.  In other words, the Next and Prev
+** opcodes do not work after this operation.
+**
+** See also: Found, NotExists, NoConflict, IfNoHope
+*/
+/* Opcode: IfNoHope P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** Register P3 is the first of P4 registers that form an unpacked
+** record.  Cursor P1 is an index btree.  P2 is a jump destination.
+** In other words, the operands to this opcode are the same as the
+** operands to OP_NotFound and OP_IdxGT.
+**
+** This opcode is an optimization attempt only.  If this opcode always
+** falls through, the correct answer is still obtained, but extra work
+** is performed.
+**
+** A value of N in the seekHit flag of cursor P1 means that there exists
+** a key P3:N that will match some record in the index.  We want to know
+** if it is possible for a record P3:P4 to match some record in the
+** index.  If it is not possible, we can skip some work.  So if seekHit
+** is less than P4, attempt to find out if a match is possible by running
+** OP_NotFound.
+**
+** This opcode is used in IN clause processing for a multi-column key.
+** If an IN clause is attached to an element of the key other than the
+** left-most element, and if there are no matches on the most recent
+** seek over the whole key, then it might be that one of the key element
+** to the left is prohibiting a match, and hence there is "no hope" of
+** any match regardless of how many IN clause elements are checked.
+** In such a case, we abandon the IN clause search early, using this
+** opcode.  The opcode name comes from the fact that the
+** jump is taken if there is "no hope" of achieving a match.
+**
+** See also: NotFound, SeekHit
+*/
+/* Opcode: NoConflict P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
+**
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** contains any NULL value, jump immediately to P2.  If all terms of the
+** record are not-NULL then a check is done to determine if any row in the
+** P1 index btree has a matching key prefix.  If there are no matches, jump
+** immediately to P2.  If there is a match, fall through and leave the P1
+** cursor pointing to the matching row.
+**
+** This opcode is similar to OP_NotFound with the exceptions that the
+** branch is always taken if any part of the search key input is NULL.
+**
+** This operation leaves the cursor in a state where it cannot be
+** advanced in either direction.  In other words, the Next and Prev
+** opcodes do not work after this operation.
+**
+** See also: NotFound, Found, NotExists
+*/
+case OP_IfNoHope: {     /* jump, in3, ncycle */
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+#ifdef SQLITE_DEBUG
+  if( db->flags&SQLITE_VdbeTrace ){
+    printf("seekHit is %d\n", pC->seekHit);
+  }
+#endif
+  if( pC->seekHit>=pOp->p4.i ) break;
+  /* Fall through into OP_NotFound */
+  /* no break */ deliberate_fall_through
+}
+case OP_NoConflict:     /* jump, in3, ncycle */
+case OP_NotFound:       /* jump, in3, ncycle */
+case OP_Found: {        /* jump, in3, ncycle */
+  int alreadyExists;
+  int ii;
+  VdbeCursor *pC;
+  UnpackedRecord *pIdxKey;
+  UnpackedRecord r;
+
+#ifdef SQLITE_TEST
+  if( pOp->opcode!=OP_NoConflict ) sqlite3_found_count++;
+#endif
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p4type==P4_INT32 );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+#ifdef SQLITE_DEBUG
+  pC->seekOp = pOp->opcode;
+#endif
+  r.aMem = &aMem[pOp->p3];
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->uc.pCursor!=0 );
+  assert( pC->isTable==0 );
+  r.nField = (u16)pOp->p4.i;
+  if( r.nField>0 ){
+    /* Key values in an array of registers */
+    r.pKeyInfo = pC->pKeyInfo;
+    r.default_rc = 0;
+#ifdef SQLITE_DEBUG
+    (void)sqlite3FaultSim(50);  /* For use by --counter in TH3 */
+    for(ii=0; ii<r.nField; ii++){
+      assert( memIsValid(&r.aMem[ii]) );
+      assert( (r.aMem[ii].flags & MEM_Zero)==0 || r.aMem[ii].n==0 );
+      if( ii ) REGISTER_TRACE(pOp->p3+ii, &r.aMem[ii]);
+    }
+#endif
+    rc = sqlite3BtreeIndexMoveto(pC->uc.pCursor, &r, &pC->seekResult);
+  }else{
+    /* Composite key generated by OP_MakeRecord */
+    assert( r.aMem->flags & MEM_Blob );
+    assert( pOp->opcode!=OP_NoConflict );
+    rc = ExpandBlob(r.aMem);
+    assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+    if( rc ) goto no_mem;
+    pIdxKey = sqlite3VdbeAllocUnpackedRecord(pC->pKeyInfo);
+    if( pIdxKey==0 ) goto no_mem;
+    sqlite3VdbeRecordUnpack(pC->pKeyInfo, r.aMem->n, r.aMem->z, pIdxKey);
+    pIdxKey->default_rc = 0;
+    rc = sqlite3BtreeIndexMoveto(pC->uc.pCursor, pIdxKey, &pC->seekResult);
+    sqlite3DbFreeNN(db, pIdxKey);
+  }
+  if( rc!=SQLITE_OK ){
+    goto abort_due_to_error;
+  }
+  alreadyExists = (pC->seekResult==0);
+  pC->nullRow = 1-alreadyExists;
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+  if( pOp->opcode==OP_Found ){
+    VdbeBranchTaken(alreadyExists!=0,2);
+    if( alreadyExists ) goto jump_to_p2;
+  }else{
+    if( !alreadyExists ){
+      VdbeBranchTaken(1,2);
+      goto jump_to_p2;
+    }
+    if( pOp->opcode==OP_NoConflict ){
+      /* For the OP_NoConflict opcode, take the jump if any of the
+      ** input fields are NULL, since any key with a NULL will not
+      ** conflict */
+      for(ii=0; ii<r.nField; ii++){
+        if( r.aMem[ii].flags & MEM_Null ){
+          VdbeBranchTaken(1,2);
+          goto jump_to_p2;
+        }
+      }
+    }
+    VdbeBranchTaken(0,2);
+    if( pOp->opcode==OP_IfNoHope ){
+      pC->seekHit = pOp->p4.i;
+    }
+  }
+  break;
+}
+
+/* Opcode: SeekRowid P1 P2 P3 * *
+** Synopsis: intkey=r[P3]
+**
+** P1 is the index of a cursor open on an SQL table btree (with integer
+** keys).  If register P3 does not contain an integer or if P1 does not
+** contain a record with rowid P3 then jump immediately to P2.
+** Or, if P2 is 0, raise an SQLITE_CORRUPT error. If P1 does contain
+** a record with rowid P3 then
+** leave the cursor pointing at that record and fall through to the next
+** instruction.
+**
+** The OP_NotExists opcode performs the same operation, but with OP_NotExists
+** the P3 register must be guaranteed to contain an integer value.  With this
+** opcode, register P3 might not contain an integer.
+**
+** The OP_NotFound opcode performs the same operation on index btrees
+** (with arbitrary multi-value keys).
+**
+** This opcode leaves the cursor in a state where it cannot be advanced
+** in either direction.  In other words, the Next and Prev opcodes will
+** not work following this opcode.
+**
+** See also: Found, NotFound, NoConflict, SeekRowid
+*/
+/* Opcode: NotExists P1 P2 P3 * *
+** Synopsis: intkey=r[P3]
+**
+** P1 is the index of a cursor open on an SQL table btree (with integer
+** keys).  P3 is an integer rowid.  If P1 does not contain a record with
+** rowid P3 then jump immediately to P2.  Or, if P2 is 0, raise an
+** SQLITE_CORRUPT error. If P1 does contain a record with rowid P3 then
+** leave the cursor pointing at that record and fall through to the next
+** instruction.
+**
+** The OP_SeekRowid opcode performs the same operation but also allows the
+** P3 register to contain a non-integer value, in which case the jump is
+** always taken.  This opcode requires that P3 always contain an integer.
+**
+** The OP_NotFound opcode performs the same operation on index btrees
+** (with arbitrary multi-value keys).
+**
+** This opcode leaves the cursor in a state where it cannot be advanced
+** in either direction.  In other words, the Next and Prev opcodes will
+** not work following this opcode.
+**
+** See also: Found, NotFound, NoConflict, SeekRowid
+*/
+case OP_SeekRowid: {        /* jump0, in3, ncycle */
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+  u64 iKey;
+
+  pIn3 = &aMem[pOp->p3];
+  testcase( pIn3->flags & MEM_Int );
+  testcase( pIn3->flags & MEM_IntReal );
+  testcase( pIn3->flags & MEM_Real );
+  testcase( (pIn3->flags & (MEM_Str|MEM_Int))==MEM_Str );
+  if( (pIn3->flags & (MEM_Int|MEM_IntReal))==0 ){
+    /* If pIn3->u.i does not contain an integer, compute iKey as the
+    ** integer value of pIn3.  Jump to P2 if pIn3 cannot be converted
+    ** into an integer without loss of information.  Take care to avoid
+    ** changing the datatype of pIn3, however, as it is used by other
+    ** parts of the prepared statement. */
+    Mem x = pIn3[0];
+    applyAffinity(&x, SQLITE_AFF_NUMERIC, encoding);
+    if( (x.flags & MEM_Int)==0 ) goto jump_to_p2;
+    iKey = x.u.i;
+    goto notExistsWithKey;
+  }
+  /* Fall through into OP_NotExists */
+  /* no break */ deliberate_fall_through
+case OP_NotExists:          /* jump, in3, ncycle */
+  pIn3 = &aMem[pOp->p3];
+  assert( (pIn3->flags & MEM_Int)!=0 || pOp->opcode==OP_SeekRowid );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  iKey = pIn3->u.i;
+notExistsWithKey:
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+#ifdef SQLITE_DEBUG
+  if( pOp->opcode==OP_SeekRowid ) pC->seekOp = OP_SeekRowid;
+#endif
+  assert( pC->isTable );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  pCrsr = pC->uc.pCursor;
+  assert( pCrsr!=0 );
+  res = 0;
+  rc = sqlite3BtreeTableMoveto(pCrsr, iKey, 0, &res);
+  assert( rc==SQLITE_OK || res==0 );
+  pC->movetoTarget = iKey;  /* Used by OP_Delete */
+  pC->nullRow = 0;
+  pC->cacheStatus = CACHE_STALE;
+  pC->deferredMoveto = 0;
+  VdbeBranchTaken(res!=0,2);
+  pC->seekResult = res;
+  if( res!=0 ){
+    assert( rc==SQLITE_OK );
+    if( pOp->p2==0 ){
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      goto jump_to_p2;
+    }
+  }
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: Sequence P1 P2 * * *
+** Synopsis: r[P2]=cursor[P1].ctr++
+**
+** Find the next available sequence number for cursor P1.
+** Write the sequence number into register P2.
+** The sequence number on the cursor is incremented after this
+** instruction.
+*/
+case OP_Sequence: {           /* out2 */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( p->apCsr[pOp->p1]!=0 );
+  assert( p->apCsr[pOp->p1]->eCurType!=CURTYPE_VTAB );
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = p->apCsr[pOp->p1]->seqCount++;
+  break;
+}
+
+
+/* Opcode: NewRowid P1 P2 P3 * *
+** Synopsis: r[P2]=rowid
+**
+** Get a new integer record number (a.k.a "rowid") used as the key to a table.
+** The record number is not previously used as a key in the database
+** table that cursor P1 points to.  The new record number is written
+** written to register P2.
+**
+** If P3>0 then P3 is a register in the root frame of this VDBE that holds
+** the largest previously generated record number. No new record numbers are
+** allowed to be less than this value. When this value reaches its maximum,
+** an SQLITE_FULL error is generated. The P3 register is updated with the '
+** generated record number. This P3 mechanism is used to help implement the
+** AUTOINCREMENT feature.
+*/
+case OP_NewRowid: {           /* out2 */
+  i64 v;                 /* The new rowid */
+  VdbeCursor *pC;        /* Cursor of table to get the new rowid */
+  int res;               /* Result of an sqlite3BtreeLast() */
+  int cnt;               /* Counter to limit the number of searches */
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+  Mem *pMem;             /* Register holding largest rowid for AUTOINCREMENT */
+  VdbeFrame *pFrame;     /* Root frame of VDBE */
+#endif
+
+  v = 0;
+  res = 0;
+  pOut = out2Prerelease(p, pOp);
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->isTable );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->uc.pCursor!=0 );
+  {
+    /* The next rowid or record number (different terms for the same
+    ** thing) is obtained in a two-step algorithm.
+    **
+    ** First we attempt to find the largest existing rowid and add one
+    ** to that.  But if the largest existing rowid is already the maximum
+    ** positive integer, we have to fall through to the second
+    ** probabilistic algorithm
+    **
+    ** The second algorithm is to select a rowid at random and see if
+    ** it already exists in the table.  If it does not exist, we have
+    ** succeeded.  If the random rowid does exist, we select a new one
+    ** and try again, up to 100 times.
+    */
+    assert( pC->isTable );
+
+#ifdef SQLITE_32BIT_ROWID
+#   define MAX_ROWID 0x7fffffff
+#else
+    /* Some compilers complain about constants of the form 0x7fffffffffffffff.
+    ** Others complain about 0x7ffffffffffffffffLL.  The following macro seems
+    ** to provide the constant while making all compilers happy.
+    */
+#   define MAX_ROWID  (i64)( (((u64)0x7fffffff)<<32) | (u64)0xffffffff )
+#endif
+
+    if( !pC->useRandomRowid ){
+      rc = sqlite3BtreeLast(pC->uc.pCursor, &res);
+      if( rc!=SQLITE_OK ){
+        goto abort_due_to_error;
+      }
+      if( res ){
+        v = 1;   /* IMP: R-61914-48074 */
+      }else{
+        assert( sqlite3BtreeCursorIsValid(pC->uc.pCursor) );
+        v = sqlite3BtreeIntegerKey(pC->uc.pCursor);
+        if( v>=MAX_ROWID ){
+          pC->useRandomRowid = 1;
+        }else{
+          v++;   /* IMP: R-29538-34987 */
+        }
+      }
+    }
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    if( pOp->p3 ){
+      /* Assert that P3 is a valid memory cell. */
+      assert( pOp->p3>0 );
+      if( p->pFrame ){
+        for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
+        /* Assert that P3 is a valid memory cell. */
+        assert( pOp->p3<=pFrame->nMem );
+        pMem = &pFrame->aMem[pOp->p3];
+      }else{
+        /* Assert that P3 is a valid memory cell. */
+        assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+        pMem = &aMem[pOp->p3];
+        memAboutToChange(p, pMem);
+      }
+      assert( memIsValid(pMem) );
+
+      REGISTER_TRACE(pOp->p3, pMem);
+      sqlite3VdbeMemIntegerify(pMem);
+      assert( (pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
+      if( pMem->u.i==MAX_ROWID || pC->useRandomRowid ){
+        rc = SQLITE_FULL;   /* IMP: R-17817-00630 */
+        goto abort_due_to_error;
+      }
+      if( v<pMem->u.i+1 ){
+        v = pMem->u.i + 1;
+      }
+      pMem->u.i = v;
+    }
+#endif
+    if( pC->useRandomRowid ){
+      /* IMPLEMENTATION-OF: R-07677-41881 If the largest ROWID is equal to the
+      ** largest possible integer (9223372036854775807) then the database
+      ** engine starts picking positive candidate ROWIDs at random until
+      ** it finds one that is not previously used. */
+      assert( pOp->p3==0 );  /* We cannot be in random rowid mode if this is
+                             ** an AUTOINCREMENT table. */
+      cnt = 0;
+      do{
+        sqlite3_randomness(sizeof(v), &v);
+        v &= (MAX_ROWID>>1); v++;  /* Ensure that v is greater than zero */
+      }while(  ((rc = sqlite3BtreeTableMoveto(pC->uc.pCursor, (u64)v,
+                                                 0, &res))==SQLITE_OK)
+            && (res==0)
+            && (++cnt<100));
+      if( rc ) goto abort_due_to_error;
+      if( res==0 ){
+        rc = SQLITE_FULL;   /* IMP: R-38219-53002 */
+        goto abort_due_to_error;
+      }
+      assert( v>0 );  /* EV: R-40812-03570 */
+    }
+    pC->deferredMoveto = 0;
+    pC->cacheStatus = CACHE_STALE;
+  }
+  pOut->u.i = v;
+  break;
+}
+
+/* Opcode: Insert P1 P2 P3 P4 P5
+** Synopsis: intkey=r[P3] data=r[P2]
+**
+** Write an entry into the table of cursor P1.  A new entry is
+** created if it doesn't already exist or the data for an existing
+** entry is overwritten.  The data is the value MEM_Blob stored in register
+** number P2. The key is stored in register P3. The key must
+** be a MEM_Int.
+**
+** If the OPFLAG_NCHANGE flag of P5 is set, then the row change count is
+** incremented (otherwise not).  If the OPFLAG_LASTROWID flag of P5 is set,
+** then rowid is stored for subsequent return by the
+** sqlite3_last_insert_rowid() function (otherwise it is unmodified).
+**
+** If the OPFLAG_USESEEKRESULT flag of P5 is set, the implementation might
+** run faster by avoiding an unnecessary seek on cursor P1.  However,
+** the OPFLAG_USESEEKRESULT flag must only be set if there have been no prior
+** seeks on the cursor or if the most recent seek used a key equal to P3.
+**
+** If the OPFLAG_ISUPDATE flag is set, then this opcode is part of an
+** UPDATE operation.  Otherwise (if the flag is clear) then this opcode
+** is part of an INSERT operation.  The difference is only important to
+** the update hook.
+**
+** Parameter P4 may point to a Table structure, or may be NULL. If it is
+** not NULL, then the update-hook (sqlite3.xUpdateCallback) is invoked
+** following a successful insert.
+**
+** (WARNING/TODO: If P1 is a pseudo-cursor and P2 is dynamically
+** allocated, then ownership of P2 is transferred to the pseudo-cursor
+** and register P2 becomes ephemeral.  If the cursor is changed, the
+** value of register P2 will then change.  Make sure this does not
+** cause any problems.)
+**
+** This instruction only works on tables.  The equivalent instruction
+** for indices is OP_IdxInsert.
+*/
+case OP_Insert: {
+  Mem *pData;       /* MEM cell holding data for the record to be inserted */
+  Mem *pKey;        /* MEM cell holding key  for the record */
+  VdbeCursor *pC;   /* Cursor to table into which insert is written */
+  int seekResult;   /* Result of prior seek or 0 if no USESEEKRESULT flag */
+  const char *zDb;  /* database name - used by the update hook */
+  Table *pTab;      /* Table structure - used by update and pre-update hooks */
+  BtreePayload x;   /* Payload to be inserted */
+
+  pData = &aMem[pOp->p2];
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( memIsValid(pData) );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->deferredMoveto==0 );
+  assert( pC->uc.pCursor!=0 );
+  assert( (pOp->p5 & OPFLAG_ISNOOP) || pC->isTable );
+  assert( pOp->p4type==P4_TABLE || pOp->p4type>=P4_STATIC );
+  REGISTER_TRACE(pOp->p2, pData);
+  sqlite3VdbeIncrWriteCounter(p, pC);
+
+  pKey = &aMem[pOp->p3];
+  assert( pKey->flags & MEM_Int );
+  assert( memIsValid(pKey) );
+  REGISTER_TRACE(pOp->p3, pKey);
+  x.nKey = pKey->u.i;
+
+  if( pOp->p4type==P4_TABLE && HAS_UPDATE_HOOK(db) ){
+    assert( pC->iDb>=0 );
+    zDb = db->aDb[pC->iDb].zDbSName;
+    pTab = pOp->p4.pTab;
+    assert( (pOp->p5 & OPFLAG_ISNOOP) || HasRowid(pTab) );
+  }else{
+    pTab = 0;
+    zDb = 0;
+  }
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  /* Invoke the pre-update hook, if any */
+  if( pTab ){
+    if( db->xPreUpdateCallback && !(pOp->p5 & OPFLAG_ISUPDATE) ){
+      sqlite3VdbePreUpdateHook(p,pC,SQLITE_INSERT,zDb,pTab,x.nKey,pOp->p2,-1);
+    }
+    if( db->xUpdateCallback==0 || pTab->aCol==0 ){
+      /* Prevent post-update hook from running in cases when it should not */
+      pTab = 0;
+    }
+  }
+  if( pOp->p5 & OPFLAG_ISNOOP ) break;
+#endif
+
+  assert( (pOp->p5 & OPFLAG_LASTROWID)==0 || (pOp->p5 & OPFLAG_NCHANGE)!=0 );
+  if( pOp->p5 & OPFLAG_NCHANGE ){
+    p->nChange++;
+    if( pOp->p5 & OPFLAG_LASTROWID ) db->lastRowid = x.nKey;
+  }
+  assert( (pData->flags & (MEM_Blob|MEM_Str))!=0 || pData->n==0 );
+  x.pData = pData->z;
+  x.nData = pData->n;
+  seekResult = ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0);
+  if( pData->flags & MEM_Zero ){
+    x.nZero = pData->u.nZero;
+  }else{
+    x.nZero = 0;
+  }
+  x.pKey = 0;
+  assert( BTREE_PREFORMAT==OPFLAG_PREFORMAT );
+  rc = sqlite3BtreeInsert(pC->uc.pCursor, &x,
+      (pOp->p5 & (OPFLAG_APPEND|OPFLAG_SAVEPOSITION|OPFLAG_PREFORMAT)),
+      seekResult
+  );
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+  colCacheCtr++;
+
+  /* Invoke the update-hook if required. */
+  if( rc ) goto abort_due_to_error;
+  if( pTab ){
+    assert( db->xUpdateCallback!=0 );
+    assert( pTab->aCol!=0 );
+    db->xUpdateCallback(db->pUpdateArg,
+           (pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT,
+           zDb, pTab->zName, x.nKey);
+  }
+  break;
+}
+
+/* Opcode: RowCell P1 P2 P3 * *
+**
+** P1 and P2 are both open cursors. Both must be opened on the same type
+** of table - intkey or index. This opcode is used as part of copying
+** the current row from P2 into P1. If the cursors are opened on intkey
+** tables, register P3 contains the rowid to use with the new record in
+** P1. If they are opened on index tables, P3 is not used.
+**
+** This opcode must be followed by either an Insert or InsertIdx opcode
+** with the OPFLAG_PREFORMAT flag set to complete the insert operation.
+*/
+case OP_RowCell: {
+  VdbeCursor *pDest;              /* Cursor to write to */
+  VdbeCursor *pSrc;               /* Cursor to read from */
+  i64 iKey;                       /* Rowid value to insert with */
+  assert( pOp[1].opcode==OP_Insert || pOp[1].opcode==OP_IdxInsert );
+  assert( pOp[1].opcode==OP_Insert    || pOp->p3==0 );
+  assert( pOp[1].opcode==OP_IdxInsert || pOp->p3>0 );
+  assert( pOp[1].p5 & OPFLAG_PREFORMAT );
+  pDest = p->apCsr[pOp->p1];
+  pSrc = p->apCsr[pOp->p2];
+  iKey = pOp->p3 ? aMem[pOp->p3].u.i : 0;
+  rc = sqlite3BtreeTransferRow(pDest->uc.pCursor, pSrc->uc.pCursor, iKey);
+  if( rc!=SQLITE_OK ) goto abort_due_to_error;
+  break;
+};
+
+/* Opcode: Delete P1 P2 P3 P4 P5
+**
+** Delete the record at which the P1 cursor is currently pointing.
+**
+** If the OPFLAG_SAVEPOSITION bit of the P5 parameter is set, then
+** the cursor will be left pointing at  either the next or the previous
+** record in the table. If it is left pointing at the next record, then
+** the next Next instruction will be a no-op. As a result, in this case
+** it is ok to delete a record from within a Next loop. If
+** OPFLAG_SAVEPOSITION bit of P5 is clear, then the cursor will be
+** left in an undefined state.
+**
+** If the OPFLAG_AUXDELETE bit is set on P5, that indicates that this
+** delete is one of several associated with deleting a table row and
+** all its associated index entries.  Exactly one of those deletes is
+** the "primary" delete.  The others are all on OPFLAG_FORDELETE
+** cursors or else are marked with the AUXDELETE flag.
+**
+** If the OPFLAG_NCHANGE (0x01) flag of P2 (NB: P2 not P5) is set, then
+** the row change count is incremented (otherwise not).
+**
+** If the OPFLAG_ISNOOP (0x40) flag of P2 (not P5!) is set, then the
+** pre-update-hook for deletes is run, but the btree is otherwise unchanged.
+** This happens when the OP_Delete is to be shortly followed by an OP_Insert
+** with the same key, causing the btree entry to be overwritten.
+**
+** P1 must not be pseudo-table.  It has to be a real table with
+** multiple rows.
+**
+** If P4 is not NULL then it points to a Table object. In this case either
+** the update or pre-update hook, or both, may be invoked. The P1 cursor must
+** have been positioned using OP_NotFound prior to invoking this opcode in
+** this case. Specifically, if one is configured, the pre-update hook is
+** invoked if P4 is not NULL. The update-hook is invoked if one is configured,
+** P4 is not NULL, and the OPFLAG_NCHANGE flag is set in P2.
+**
+** If the OPFLAG_ISUPDATE flag is set in P2, then P3 contains the address
+** of the memory cell that contains the value that the rowid of the row will
+** be set to by the update.
+*/
+case OP_Delete: {
+  VdbeCursor *pC;
+  const char *zDb;
+  Table *pTab;
+  int opflags;
+
+  opflags = pOp->p2;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->uc.pCursor!=0 );
+  assert( pC->deferredMoveto==0 );
+  sqlite3VdbeIncrWriteCounter(p, pC);
+
+#ifdef SQLITE_DEBUG
+  if( pOp->p4type==P4_TABLE
+   && HasRowid(pOp->p4.pTab)
+   && pOp->p5==0
+   && sqlite3BtreeCursorIsValidNN(pC->uc.pCursor)
+  ){
+    /* If p5 is zero, the seek operation that positioned the cursor prior to
+    ** OP_Delete will have also set the pC->movetoTarget field to the rowid of
+    ** the row that is being deleted */
+    i64 iKey = sqlite3BtreeIntegerKey(pC->uc.pCursor);
+    assert( CORRUPT_DB || pC->movetoTarget==iKey );
+  }
+#endif
+
+  /* If the update-hook or pre-update-hook will be invoked, set zDb to
+  ** the name of the db to pass as to it. Also set local pTab to a copy
+  ** of p4.pTab. Finally, if p5 is true, indicating that this cursor was
+  ** last moved with OP_Next or OP_Prev, not Seek or NotFound, set
+  ** VdbeCursor.movetoTarget to the current rowid.  */
+  if( pOp->p4type==P4_TABLE && HAS_UPDATE_HOOK(db) ){
+    assert( pC->iDb>=0 );
+    assert( pOp->p4.pTab!=0 );
+    zDb = db->aDb[pC->iDb].zDbSName;
+    pTab = pOp->p4.pTab;
+    if( (pOp->p5 & OPFLAG_SAVEPOSITION)!=0 && pC->isTable ){
+      pC->movetoTarget = sqlite3BtreeIntegerKey(pC->uc.pCursor);
+    }
+  }else{
+    zDb = 0;
+    pTab = 0;
+  }
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  /* Invoke the pre-update-hook if required. */
+  assert( db->xPreUpdateCallback==0 || pTab==pOp->p4.pTab );
+  if( db->xPreUpdateCallback && pTab ){
+    assert( !(opflags & OPFLAG_ISUPDATE)
+         || HasRowid(pTab)==0
+         || (aMem[pOp->p3].flags & MEM_Int)
+    );
+    sqlite3VdbePreUpdateHook(p, pC,
+        (opflags & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_DELETE,
+        zDb, pTab, pC->movetoTarget,
+        pOp->p3, -1
+    );
+  }
+  if( opflags & OPFLAG_ISNOOP ) break;
+#endif
+
+  /* Only flags that can be set are SAVEPOISTION and AUXDELETE */
+  assert( (pOp->p5 & ~(OPFLAG_SAVEPOSITION|OPFLAG_AUXDELETE))==0 );
+  assert( OPFLAG_SAVEPOSITION==BTREE_SAVEPOSITION );
+  assert( OPFLAG_AUXDELETE==BTREE_AUXDELETE );
+
+#ifdef SQLITE_DEBUG
+  if( p->pFrame==0 ){
+    if( pC->isEphemeral==0
+        && (pOp->p5 & OPFLAG_AUXDELETE)==0
+        && (pC->wrFlag & OPFLAG_FORDELETE)==0
+      ){
+      nExtraDelete++;
+    }
+    if( pOp->p2 & OPFLAG_NCHANGE ){
+      nExtraDelete--;
+    }
+  }
+#endif
+
+  rc = sqlite3BtreeDelete(pC->uc.pCursor, pOp->p5);
+  pC->cacheStatus = CACHE_STALE;
+  colCacheCtr++;
+  pC->seekResult = 0;
+  if( rc ) goto abort_due_to_error;
+
+  /* Invoke the update-hook if required. */
+  if( opflags & OPFLAG_NCHANGE ){
+    p->nChange++;
+    if( db->xUpdateCallback && ALWAYS(pTab!=0) && HasRowid(pTab) ){
+      db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, pTab->zName,
+          pC->movetoTarget);
+      assert( pC->iDb>=0 );
+    }
+  }
+
+  break;
+}
+/* Opcode: ResetCount * * * * *
+**
+** The value of the change counter is copied to the database handle
+** change counter (returned by subsequent calls to sqlite3_changes()).
+** Then the VMs internal change counter resets to 0.
+** This is used by trigger programs.
+*/
+case OP_ResetCount: {
+  sqlite3VdbeSetChanges(db, p->nChange);
+  p->nChange = 0;
+  break;
+}
+
+/* Opcode: SorterCompare P1 P2 P3 P4
+** Synopsis: if key(P1)!=trim(r[P3],P4) goto P2
+**
+** P1 is a sorter cursor. This instruction compares a prefix of the
+** record blob in register P3 against a prefix of the entry that
+** the sorter cursor currently points to.  Only the first P4 fields
+** of r[P3] and the sorter record are compared.
+**
+** If either P3 or the sorter contains a NULL in one of their significant
+** fields (not counting the P4 fields at the end which are ignored) then
+** the comparison is assumed to be equal.
+**
+** Fall through to next instruction if the two records compare equal to
+** each other.  Jump to P2 if they are different.
+*/
+case OP_SorterCompare: {
+  VdbeCursor *pC;
+  int res;
+  int nKeyCol;
+
+  pC = p->apCsr[pOp->p1];
+  assert( isSorter(pC) );
+  assert( pOp->p4type==P4_INT32 );
+  pIn3 = &aMem[pOp->p3];
+  nKeyCol = pOp->p4.i;
+  res = 0;
+  rc = sqlite3VdbeSorterCompare(pC, pIn3, nKeyCol, &res);
+  VdbeBranchTaken(res!=0,2);
+  if( rc ) goto abort_due_to_error;
+  if( res ) goto jump_to_p2;
+  break;
+};
+
+/* Opcode: SorterData P1 P2 P3 * *
+** Synopsis: r[P2]=data
+**
+** Write into register P2 the current sorter data for sorter cursor P1.
+** Then clear the column header cache on cursor P3.
+**
+** This opcode is normally used to move a record out of the sorter and into
+** a register that is the source for a pseudo-table cursor created using
+** OpenPseudo.  That pseudo-table cursor is the one that is identified by
+** parameter P3.  Clearing the P3 column cache as part of this opcode saves
+** us from having to issue a separate NullRow instruction to clear that cache.
+*/
+case OP_SorterData: {       /* ncycle */
+  VdbeCursor *pC;
+
+  pOut = &aMem[pOp->p2];
+  pC = p->apCsr[pOp->p1];
+  assert( isSorter(pC) );
+  rc = sqlite3VdbeSorterRowkey(pC, pOut);
+  assert( rc!=SQLITE_OK || (pOut->flags & MEM_Blob) );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  if( rc ) goto abort_due_to_error;
+  p->apCsr[pOp->p3]->cacheStatus = CACHE_STALE;
+  break;
+}
+
+/* Opcode: RowData P1 P2 P3 * *
+** Synopsis: r[P2]=data
+**
+** Write into register P2 the complete row content for the row at
+** which cursor P1 is currently pointing.
+** There is no interpretation of the data.
+** It is just copied onto the P2 register exactly as
+** it is found in the database file.
+**
+** If cursor P1 is an index, then the content is the key of the row.
+** If cursor P2 is a table, then the content extracted is the data.
+**
+** If the P1 cursor must be pointing to a valid row (not a NULL row)
+** of a real table, not a pseudo-table.
+**
+** If P3!=0 then this opcode is allowed to make an ephemeral pointer
+** into the database page.  That means that the content of the output
+** register will be invalidated as soon as the cursor moves - including
+** moves caused by other cursors that "save" the current cursors
+** position in order that they can write to the same table.  If P3==0
+** then a copy of the data is made into memory.  P3!=0 is faster, but
+** P3==0 is safer.
+**
+** If P3!=0 then the content of the P2 register is unsuitable for use
+** in OP_Result and any OP_Result will invalidate the P2 register content.
+** The P2 register content is invalidated by opcodes like OP_Function or
+** by any use of another cursor pointing to the same table.
+*/
+case OP_RowData: {
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  u32 n;
+
+  pOut = out2Prerelease(p, pOp);
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( isSorter(pC)==0 );
+  assert( pC->nullRow==0 );
+  assert( pC->uc.pCursor!=0 );
+  pCrsr = pC->uc.pCursor;
+
+  /* The OP_RowData opcodes always follow OP_NotExists or
+  ** OP_SeekRowid or OP_Rewind/Op_Next with no intervening instructions
+  ** that might invalidate the cursor.
+  ** If this where not the case, on of the following assert()s
+  ** would fail.  Should this ever change (because of changes in the code
+  ** generator) then the fix would be to insert a call to
+  ** sqlite3VdbeCursorMoveto().
+  */
+  assert( pC->deferredMoveto==0 );
+  assert( sqlite3BtreeCursorIsValid(pCrsr) );
+
+  n = sqlite3BtreePayloadSize(pCrsr);
+  if( n>(u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+  testcase( n==0 );
+  rc = sqlite3VdbeMemFromBtreeZeroOffset(pCrsr, n, pOut);
+  if( rc ) goto abort_due_to_error;
+  if( !pOp->p3 ) Deephemeralize(pOut);
+  UPDATE_MAX_BLOBSIZE(pOut);
+  REGISTER_TRACE(pOp->p2, pOut);
+  break;
+}
+
+/* Opcode: Rowid P1 P2 * * *
+** Synopsis: r[P2]=PX rowid of P1
+**
+** Store in register P2 an integer which is the key of the table entry that
+** P1 is currently point to.
+**
+** P1 can be either an ordinary table or a virtual table.  There used to
+** be a separate OP_VRowid opcode for use with virtual tables, but this
+** one opcode now works for both table types.
+*/
+case OP_Rowid: {                 /* out2, ncycle */
+  VdbeCursor *pC;
+  i64 v;
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+
+  pOut = out2Prerelease(p, pOp);
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType!=CURTYPE_PSEUDO || pC->nullRow );
+  if( pC->nullRow ){
+    pOut->flags = MEM_Null;
+    break;
+  }else if( pC->deferredMoveto ){
+    v = pC->movetoTarget;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  }else if( pC->eCurType==CURTYPE_VTAB ){
+    assert( pC->uc.pVCur!=0 );
+    pVtab = pC->uc.pVCur->pVtab;
+    pModule = pVtab->pModule;
+    assert( pModule->xRowid );
+    rc = pModule->xRowid(pC->uc.pVCur, &v);
+    sqlite3VtabImportErrmsg(p, pVtab);
+    if( rc ) goto abort_due_to_error;
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+  }else{
+    assert( pC->eCurType==CURTYPE_BTREE );
+    assert( pC->uc.pCursor!=0 );
+    rc = sqlite3VdbeCursorRestore(pC);
+    if( rc ) goto abort_due_to_error;
+    if( pC->nullRow ){
+      pOut->flags = MEM_Null;
+      break;
+    }
+    v = sqlite3BtreeIntegerKey(pC->uc.pCursor);
+  }
+  pOut->u.i = v;
+  break;
+}
+
+/* Opcode: NullRow P1 * * * *
+**
+** Move the cursor P1 to a null row.  Any OP_Column operations
+** that occur while the cursor is on the null row will always
+** write a NULL.
+**
+** If cursor P1 is not previously opened, open it now to a special
+** pseudo-cursor that always returns NULL for every column.
+*/
+case OP_NullRow: {
+  VdbeCursor *pC;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  if( pC==0 ){
+    /* If the cursor is not already open, create a special kind of
+    ** pseudo-cursor that always gives null rows. */
+    pC = allocateCursor(p, pOp->p1, 1, CURTYPE_PSEUDO);
+    if( pC==0 ) goto no_mem;
+    pC->seekResult = 0;
+    pC->isTable = 1;
+    pC->noReuse = 1;
+    pC->uc.pCursor = sqlite3BtreeFakeValidCursor();
+  }
+  pC->nullRow = 1;
+  pC->cacheStatus = CACHE_STALE;
+  if( pC->eCurType==CURTYPE_BTREE ){
+    assert( pC->uc.pCursor!=0 );
+    sqlite3BtreeClearCursor(pC->uc.pCursor);
+  }
+#ifdef SQLITE_DEBUG
+  if( pC->seekOp==0 ) pC->seekOp = OP_NullRow;
+#endif
+  break;
+}
+
+/* Opcode: SeekEnd P1 * * * *
+**
+** Position cursor P1 at the end of the btree for the purpose of
+** appending a new entry onto the btree.
+**
+** It is assumed that the cursor is used only for appending and so
+** if the cursor is valid, then the cursor must already be pointing
+** at the end of the btree and so no changes are made to
+** the cursor.
+*/
+/* Opcode: Last P1 P2 * * *
+**
+** The next use of the Rowid or Column or Prev instruction for P1
+** will refer to the last entry in the database table or index.
+** If the table or index is empty and P2>0, then jump immediately to P2.
+** If P2 is 0 or if the table or index is not empty, fall through
+** to the following instruction.
+**
+** This opcode leaves the cursor configured to move in reverse order,
+** from the end toward the beginning.  In other words, the cursor is
+** configured to use Prev, not Next.
+*/
+case OP_SeekEnd:             /* ncycle */
+case OP_Last: {              /* jump0, ncycle */
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  pCrsr = pC->uc.pCursor;
+  res = 0;
+  assert( pCrsr!=0 );
+#ifdef SQLITE_DEBUG
+  pC->seekOp = pOp->opcode;
+#endif
+  if( pOp->opcode==OP_SeekEnd ){
+    assert( pOp->p2==0 );
+    pC->seekResult = -1;
+    if( sqlite3BtreeCursorIsValidNN(pCrsr) ){
+      break;
+    }
+  }
+  rc = sqlite3BtreeLast(pCrsr, &res);
+  pC->nullRow = (u8)res;
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+  if( rc ) goto abort_due_to_error;
+  if( pOp->p2>0 ){
+    VdbeBranchTaken(res!=0,2);
+    if( res ) goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: IfSizeBetween P1 P2 P3 P4 *
+**
+** Let N be the approximate number of rows in the table or index
+** with cursor P1 and let X be 10*log2(N) if N is positive or -1
+** if N is zero.
+**
+** Jump to P2 if X is in between P3 and P4, inclusive.
+*/
+case OP_IfSizeBetween: {        /* jump */
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+  i64 sz;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p4type==P4_INT32 );
+  assert( pOp->p3>=-1 && pOp->p3<=640*2 );
+  assert( pOp->p4.i>=-1 && pOp->p4.i<=640*2 );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  pCrsr = pC->uc.pCursor;
+  assert( pCrsr );
+  rc = sqlite3BtreeFirst(pCrsr, &res);
+  if( rc ) goto abort_due_to_error;
+  if( res!=0 ){
+    sz = -1;  /* -Infinity encoding */
+  }else{
+    sz = sqlite3BtreeRowCountEst(pCrsr);
+    assert( sz>0 );
+    sz = sqlite3LogEst((u64)sz);
+  }
+  res = sz>=pOp->p3 && sz<=pOp->p4.i;
+  VdbeBranchTaken(res!=0,2);
+  if( res ) goto jump_to_p2;
+  break;
+}
+
+
+/* Opcode: SorterSort P1 P2 * * *
+**
+** After all records have been inserted into the Sorter object
+** identified by P1, invoke this opcode to actually do the sorting.
+** Jump to P2 if there are no records to be sorted.
+**
+** This opcode is an alias for OP_Sort and OP_Rewind that is used
+** for Sorter objects.
+*/
+/* Opcode: Sort P1 P2 * * *
+**
+** This opcode does exactly the same thing as OP_Rewind except that
+** it increments an undocumented global variable used for testing.
+**
+** Sorting is accomplished by writing records into a sorting index,
+** then rewinding that index and playing it back from beginning to
+** end.  We use the OP_Sort opcode instead of OP_Rewind to do the
+** rewinding so that the global variable will be incremented and
+** regression tests can determine whether or not the optimizer is
+** correctly optimizing out sorts.
+*/
+case OP_SorterSort:    /* jump ncycle */
+case OP_Sort: {        /* jump ncycle */
+#ifdef SQLITE_TEST
+  sqlite3_sort_count++;
+  sqlite3_search_count--;
+#endif
+  p->aCounter[SQLITE_STMTSTATUS_SORT]++;
+  /* Fall through into OP_Rewind */
+  /* no break */ deliberate_fall_through
+}
+/* Opcode: Rewind P1 P2 * * *
+**
+** The next use of the Rowid or Column or Next instruction for P1
+** will refer to the first entry in the database table or index.
+** If the table or index is empty, jump immediately to P2.
+** If the table or index is not empty, fall through to the following
+** instruction.
+**
+** If P2 is zero, that is an assertion that the P1 table is never
+** empty and hence the jump will never be taken.
+**
+** This opcode leaves the cursor configured to move in forward order,
+** from the beginning toward the end.  In other words, the cursor is
+** configured to use Next, not Prev.
+*/
+case OP_Rewind: {        /* jump0, ncycle */
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p5==0 );
+  assert( pOp->p2>=0 && pOp->p2<p->nOp );
+
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( isSorter(pC)==(pOp->opcode==OP_SorterSort) );
+  res = 1;
+#ifdef SQLITE_DEBUG
+  pC->seekOp = OP_Rewind;
+#endif
+  if( isSorter(pC) ){
+    rc = sqlite3VdbeSorterRewind(pC, &res);
+  }else{
+    assert( pC->eCurType==CURTYPE_BTREE );
+    pCrsr = pC->uc.pCursor;
+    assert( pCrsr );
+    rc = sqlite3BtreeFirst(pCrsr, &res);
+    pC->deferredMoveto = 0;
+    pC->cacheStatus = CACHE_STALE;
+  }
+  if( rc ) goto abort_due_to_error;
+  pC->nullRow = (u8)res;
+  if( pOp->p2>0 ){
+    VdbeBranchTaken(res!=0,2);
+    if( res ) goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: Next P1 P2 P3 * P5
+**
+** Advance cursor P1 so that it points to the next key/data pair in its
+** table or index.  If there are no more key/value pairs then fall through
+** to the following instruction.  But if the cursor advance was successful,
+** jump immediately to P2.
+**
+** The Next opcode is only valid following an SeekGT, SeekGE, or
+** OP_Rewind opcode used to position the cursor.  Next is not allowed
+** to follow SeekLT, SeekLE, or OP_Last.
+**
+** The P1 cursor must be for a real table, not a pseudo-table.  P1 must have
+** been opened prior to this opcode or the program will segfault.
+**
+** The P3 value is a hint to the btree implementation. If P3==1, that
+** means P1 is an SQL index and that this instruction could have been
+** omitted if that index had been unique.  P3 is usually 0.  P3 is
+** always either 0 or 1.
+**
+** If P5 is positive and the jump is taken, then event counter
+** number P5-1 in the prepared statement is incremented.
+**
+** See also: Prev
+*/
+/* Opcode: Prev P1 P2 P3 * P5
+**
+** Back up cursor P1 so that it points to the previous key/data pair in its
+** table or index.  If there is no previous key/value pairs then fall through
+** to the following instruction.  But if the cursor backup was successful,
+** jump immediately to P2.
+**
+**
+** The Prev opcode is only valid following an SeekLT, SeekLE, or
+** OP_Last opcode used to position the cursor.  Prev is not allowed
+** to follow SeekGT, SeekGE, or OP_Rewind.
+**
+** The P1 cursor must be for a real table, not a pseudo-table.  If P1 is
+** not open then the behavior is undefined.
+**
+** The P3 value is a hint to the btree implementation. If P3==1, that
+** means P1 is an SQL index and that this instruction could have been
+** omitted if that index had been unique.  P3 is usually 0.  P3 is
+** always either 0 or 1.
+**
+** If P5 is positive and the jump is taken, then event counter
+** number P5-1 in the prepared statement is incremented.
+*/
+/* Opcode: SorterNext P1 P2 * * P5
+**
+** This opcode works just like OP_Next except that P1 must be a
+** sorter object for which the OP_SorterSort opcode has been
+** invoked.  This opcode advances the cursor to the next sorted
+** record, or jumps to P2 if there are no more sorted records.
+*/
+case OP_SorterNext: {  /* jump */
+  VdbeCursor *pC;
+
+  pC = p->apCsr[pOp->p1];
+  assert( isSorter(pC) );
+  rc = sqlite3VdbeSorterNext(db, pC);
+  goto next_tail;
+
+case OP_Prev:          /* jump, ncycle */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p5==0
+       || pOp->p5==SQLITE_STMTSTATUS_FULLSCAN_STEP
+       || pOp->p5==SQLITE_STMTSTATUS_AUTOINDEX);
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->deferredMoveto==0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->seekOp==OP_SeekLT || pC->seekOp==OP_SeekLE
+       || pC->seekOp==OP_Last   || pC->seekOp==OP_IfNoHope
+       || pC->seekOp==OP_NullRow);
+  rc = sqlite3BtreePrevious(pC->uc.pCursor, pOp->p3);
+  goto next_tail;
+
+case OP_Next:          /* jump, ncycle */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p5==0
+       || pOp->p5==SQLITE_STMTSTATUS_FULLSCAN_STEP
+       || pOp->p5==SQLITE_STMTSTATUS_AUTOINDEX);
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->deferredMoveto==0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->seekOp==OP_SeekGT || pC->seekOp==OP_SeekGE
+       || pC->seekOp==OP_Rewind || pC->seekOp==OP_Found
+       || pC->seekOp==OP_NullRow|| pC->seekOp==OP_SeekRowid
+       || pC->seekOp==OP_IfNoHope);
+  rc = sqlite3BtreeNext(pC->uc.pCursor, pOp->p3);
+
+next_tail:
+  pC->cacheStatus = CACHE_STALE;
+  VdbeBranchTaken(rc==SQLITE_OK,2);
+  if( rc==SQLITE_OK ){
+    pC->nullRow = 0;
+    p->aCounter[pOp->p5]++;
+#ifdef SQLITE_TEST
+    sqlite3_search_count++;
+#endif
+    goto jump_to_p2_and_check_for_interrupt;
+  }
+  if( rc!=SQLITE_DONE ) goto abort_due_to_error;
+  rc = SQLITE_OK;
+  pC->nullRow = 1;
+  goto check_for_interrupt;
+}
+
+/* Opcode: IdxInsert P1 P2 P3 P4 P5
+** Synopsis: key=r[P2]
+**
+** Register P2 holds an SQL index key made using the
+** MakeRecord instructions.  This opcode writes that key
+** into the index P1.  Data for the entry is nil.
+**
+** If P4 is not zero, then it is the number of values in the unpacked
+** key of reg(P2).  In that case, P3 is the index of the first register
+** for the unpacked key.  The availability of the unpacked key can sometimes
+** be an optimization.
+**
+** If P5 has the OPFLAG_APPEND bit set, that is a hint to the b-tree layer
+** that this insert is likely to be an append.
+**
+** If P5 has the OPFLAG_NCHANGE bit set, then the change counter is
+** incremented by this instruction.  If the OPFLAG_NCHANGE bit is clear,
+** then the change counter is unchanged.
+**
+** If the OPFLAG_USESEEKRESULT flag of P5 is set, the implementation might
+** run faster by avoiding an unnecessary seek on cursor P1.  However,
+** the OPFLAG_USESEEKRESULT flag must only be set if there have been no prior
+** seeks on the cursor or if the most recent seek used a key equivalent
+** to P2.
+**
+** This instruction only works for indices.  The equivalent instruction
+** for tables is OP_Insert.
+*/
+case OP_IdxInsert: {        /* in2 */
+  VdbeCursor *pC;
+  BtreePayload x;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  sqlite3VdbeIncrWriteCounter(p, pC);
+  assert( pC!=0 );
+  assert( !isSorter(pC) );
+  pIn2 = &aMem[pOp->p2];
+  assert( (pIn2->flags & MEM_Blob) || (pOp->p5 & OPFLAG_PREFORMAT) );
+  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->isTable==0 );
+  rc = ExpandBlob(pIn2);
+  if( rc ) goto abort_due_to_error;
+  x.nKey = pIn2->n;
+  x.pKey = pIn2->z;
+  x.aMem = aMem + pOp->p3;
+  x.nMem = (u16)pOp->p4.i;
+  rc = sqlite3BtreeInsert(pC->uc.pCursor, &x,
+       (pOp->p5 & (OPFLAG_APPEND|OPFLAG_SAVEPOSITION|OPFLAG_PREFORMAT)),
+      ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
+      );
+  assert( pC->deferredMoveto==0 );
+  pC->cacheStatus = CACHE_STALE;
+  if( rc) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: SorterInsert P1 P2 * * *
+** Synopsis: key=r[P2]
+**
+** Register P2 holds an SQL index key made using the
+** MakeRecord instructions.  This opcode writes that key
+** into the sorter P1.  Data for the entry is nil.
+*/
+case OP_SorterInsert: {     /* in2 */
+  VdbeCursor *pC;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  sqlite3VdbeIncrWriteCounter(p, pC);
+  assert( pC!=0 );
+  assert( isSorter(pC) );
+  pIn2 = &aMem[pOp->p2];
+  assert( pIn2->flags & MEM_Blob );
+  assert( pC->isTable==0 );
+  rc = ExpandBlob(pIn2);
+  if( rc ) goto abort_due_to_error;
+  rc = sqlite3VdbeSorterWrite(pC, pIn2);
+  if( rc) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: IdxDelete P1 P2 P3 * P5
+** Synopsis: key=r[P2@P3]
+**
+** The content of P3 registers starting at register P2 form
+** an unpacked index key. This opcode removes that entry from the
+** index opened by cursor P1.
+**
+** If P5 is not zero, then raise an SQLITE_CORRUPT_INDEX error
+** if no matching index entry is found.  This happens when running
+** an UPDATE or DELETE statement and the index entry to be updated
+** or deleted is not found.  For some uses of IdxDelete
+** (example:  the EXCEPT operator) it does not matter that no matching
+** entry is found.  For those cases, P5 is zero.  Also, do not raise
+** this (self-correcting and non-critical) error if in writable_schema mode.
+*/
+case OP_IdxDelete: {
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+  UnpackedRecord r;
+
+  assert( pOp->p3>0 );
+  assert( pOp->p2>0 && pOp->p2+pOp->p3<=(p->nMem+1 - p->nCursor)+1 );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  sqlite3VdbeIncrWriteCounter(p, pC);
+  pCrsr = pC->uc.pCursor;
+  assert( pCrsr!=0 );
+  r.pKeyInfo = pC->pKeyInfo;
+  r.nField = (u16)pOp->p3;
+  r.default_rc = 0;
+  r.aMem = &aMem[pOp->p2];
+  rc = sqlite3BtreeIndexMoveto(pCrsr, &r, &res);
+  if( rc ) goto abort_due_to_error;
+  if( res==0 ){
+    rc = sqlite3BtreeDelete(pCrsr, BTREE_AUXDELETE);
+    if( rc ) goto abort_due_to_error;
+  }else if( pOp->p5 && !sqlite3WritableSchema(db) ){
+    rc = sqlite3ReportError(SQLITE_CORRUPT_INDEX, __LINE__, "index corruption");
+    goto abort_due_to_error;
+  }
+  assert( pC->deferredMoveto==0 );
+  pC->cacheStatus = CACHE_STALE;
+  pC->seekResult = 0;
+  break;
+}
+
+/* Opcode: DeferredSeek P1 * P3 P4 *
+** Synopsis: Move P3 to P1.rowid if needed
+**
+** P1 is an open index cursor and P3 is a cursor on the corresponding
+** table.  This opcode does a deferred seek of the P3 table cursor
+** to the row that corresponds to the current row of P1.
+**
+** This is a deferred seek.  Nothing actually happens until
+** the cursor is used to read a record.  That way, if no reads
+** occur, no unnecessary I/O happens.
+**
+** P4 may be an array of integers (type P4_INTARRAY) containing
+** one entry for each column in the P3 table.  If array entry a(i)
+** is non-zero, then reading column a(i)-1 from cursor P3 is
+** equivalent to performing the deferred seek and then reading column i
+** from P1.  This information is stored in P3 and used to redirect
+** reads against P3 over to P1, thus possibly avoiding the need to
+** seek and read cursor P3.
+*/
+/* Opcode: IdxRowid P1 P2 * * *
+** Synopsis: r[P2]=rowid
+**
+** Write into register P2 an integer which is the last entry in the record at
+** the end of the index key pointed to by cursor P1.  This integer should be
+** the rowid of the table entry to which this index entry points.
+**
+** See also: Rowid, MakeRecord.
+*/
+case OP_DeferredSeek:         /* ncycle */
+case OP_IdxRowid: {           /* out2, ncycle */
+  VdbeCursor *pC;             /* The P1 index cursor */
+  VdbeCursor *pTabCur;        /* The P2 table cursor (OP_DeferredSeek only) */
+  i64 rowid;                  /* Rowid that P1 current points to */
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE || IsNullCursor(pC) );
+  assert( pC->uc.pCursor!=0 );
+  assert( pC->isTable==0 || IsNullCursor(pC) );
+  assert( pC->deferredMoveto==0 );
+  assert( !pC->nullRow || pOp->opcode==OP_IdxRowid );
+
+  /* The IdxRowid and Seek opcodes are combined because of the commonality
+  ** of sqlite3VdbeCursorRestore() and sqlite3VdbeIdxRowid(). */
+  rc = sqlite3VdbeCursorRestore(pC);
+
+  /* sqlite3VdbeCursorRestore() may fail if the cursor has been disturbed
+  ** since it was last positioned and an error (e.g. OOM or an IO error)
+  ** occurs while trying to reposition it. */
+  if( rc!=SQLITE_OK ) goto abort_due_to_error;
+
+  if( !pC->nullRow ){
+    rowid = 0;  /* Not needed.  Only used to silence a warning. */
+    rc = sqlite3VdbeIdxRowid(db, pC->uc.pCursor, &rowid);
+    if( rc!=SQLITE_OK ){
+      goto abort_due_to_error;
+    }
+    if( pOp->opcode==OP_DeferredSeek ){
+      assert( pOp->p3>=0 && pOp->p3<p->nCursor );
+      pTabCur = p->apCsr[pOp->p3];
+      assert( pTabCur!=0 );
+      assert( pTabCur->eCurType==CURTYPE_BTREE );
+      assert( pTabCur->uc.pCursor!=0 );
+      assert( pTabCur->isTable );
+      pTabCur->nullRow = 0;
+      pTabCur->movetoTarget = rowid;
+      pTabCur->deferredMoveto = 1;
+      pTabCur->cacheStatus = CACHE_STALE;
+      assert( pOp->p4type==P4_INTARRAY || pOp->p4.ai==0 );
+      assert( !pTabCur->isEphemeral );
+      pTabCur->ub.aAltMap = pOp->p4.ai;
+      assert( !pC->isEphemeral );
+      pTabCur->pAltCursor = pC;
+    }else{
+      pOut = out2Prerelease(p, pOp);
+      pOut->u.i = rowid;
+    }
+  }else{
+    assert( pOp->opcode==OP_IdxRowid );
+    sqlite3VdbeMemSetNull(&aMem[pOp->p2]);
+  }
+  break;
+}
+
+/* Opcode: FinishSeek P1 * * * *
+**
+** If cursor P1 was previously moved via OP_DeferredSeek, complete that
+** seek operation now, without further delay.  If the cursor seek has
+** already occurred, this instruction is a no-op.
+*/
+case OP_FinishSeek: {        /* ncycle */
+  VdbeCursor *pC;            /* The P1 index cursor */
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  if( pC->deferredMoveto ){
+    rc = sqlite3VdbeFinishMoveto(pC);
+    if( rc ) goto abort_due_to_error;
+  }
+  break;
+}
+
+/* Opcode: IdxGE P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** The P4 register values beginning with P3 form an unpacked index
+** key that omits the PRIMARY KEY.  Compare this key value against the index
+** that P1 is currently pointing to, ignoring the PRIMARY KEY or ROWID
+** fields at the end.
+**
+** If the P1 index entry is greater than or equal to the key value
+** then jump to P2.  Otherwise fall through to the next instruction.
+*/
+/* Opcode: IdxGT P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** The P4 register values beginning with P3 form an unpacked index
+** key that omits the PRIMARY KEY.  Compare this key value against the index
+** that P1 is currently pointing to, ignoring the PRIMARY KEY or ROWID
+** fields at the end.
+**
+** If the P1 index entry is greater than the key value
+** then jump to P2.  Otherwise fall through to the next instruction.
+*/
+/* Opcode: IdxLT P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** The P4 register values beginning with P3 form an unpacked index
+** key that omits the PRIMARY KEY or ROWID.  Compare this key value against
+** the index that P1 is currently pointing to, ignoring the PRIMARY KEY or
+** ROWID on the P1 index.
+**
+** If the P1 index entry is less than the key value then jump to P2.
+** Otherwise fall through to the next instruction.
+*/
+/* Opcode: IdxLE P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** The P4 register values beginning with P3 form an unpacked index
+** key that omits the PRIMARY KEY or ROWID.  Compare this key value against
+** the index that P1 is currently pointing to, ignoring the PRIMARY KEY or
+** ROWID on the P1 index.
+**
+** If the P1 index entry is less than or equal to the key value then jump
+** to P2. Otherwise fall through to the next instruction.
+*/
+case OP_IdxLE:          /* jump, ncycle */
+case OP_IdxGT:          /* jump, ncycle */
+case OP_IdxLT:          /* jump, ncycle */
+case OP_IdxGE:  {       /* jump, ncycle */
+  VdbeCursor *pC;
+  int res;
+  UnpackedRecord r;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->isOrdered );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->uc.pCursor!=0);
+  assert( pC->deferredMoveto==0 );
+  assert( pOp->p4type==P4_INT32 );
+  r.pKeyInfo = pC->pKeyInfo;
+  r.nField = (u16)pOp->p4.i;
+  if( pOp->opcode<OP_IdxLT ){
+    assert( pOp->opcode==OP_IdxLE || pOp->opcode==OP_IdxGT );
+    r.default_rc = -1;
+  }else{
+    assert( pOp->opcode==OP_IdxGE || pOp->opcode==OP_IdxLT );
+    r.default_rc = 0;
+  }
+  r.aMem = &aMem[pOp->p3];
+#ifdef SQLITE_DEBUG
+  {
+    int i;
+    for(i=0; i<r.nField; i++){
+      assert( memIsValid(&r.aMem[i]) );
+      REGISTER_TRACE(pOp->p3+i, &aMem[pOp->p3+i]);
+    }
+  }
+#endif
+
+  /* Inlined version of sqlite3VdbeIdxKeyCompare() */
+  {
+    i64 nCellKey = 0;
+    BtCursor *pCur;
+    Mem m;
+
+    assert( pC->eCurType==CURTYPE_BTREE );
+    pCur = pC->uc.pCursor;
+    assert( sqlite3BtreeCursorIsValid(pCur) );
+    nCellKey = sqlite3BtreePayloadSize(pCur);
+    /* nCellKey will always be between 0 and 0xffffffff because of the way
+    ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
+    if( nCellKey<=0 || nCellKey>0x7fffffff ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto abort_due_to_error;
+    }
+    sqlite3VdbeMemInit(&m, db, 0);
+    rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
+    if( rc ) goto abort_due_to_error;
+    res = sqlite3VdbeRecordCompareWithSkip(m.n, m.z, &r, 0);
+    sqlite3VdbeMemReleaseMalloc(&m);
+  }
+  /* End of inlined sqlite3VdbeIdxKeyCompare() */
+
+  assert( (OP_IdxLE&1)==(OP_IdxLT&1) && (OP_IdxGE&1)==(OP_IdxGT&1) );
+  if( (pOp->opcode&1)==(OP_IdxLT&1) ){
+    assert( pOp->opcode==OP_IdxLE || pOp->opcode==OP_IdxLT );
+    res = -res;
+  }else{
+    assert( pOp->opcode==OP_IdxGE || pOp->opcode==OP_IdxGT );
+    res++;
+  }
+  VdbeBranchTaken(res>0,2);
+  assert( rc==SQLITE_OK );
+  if( res>0 ) goto jump_to_p2;
+  break;
+}
+
+/* Opcode: Destroy P1 P2 P3 * *
+**
+** Delete an entire database table or index whose root page in the database
+** file is given by P1.
+**
+** The table being destroyed is in the main database file if P3==0.  If
+** P3==1 then the table to be destroyed is in the auxiliary database file
+** that is used to store tables create using CREATE TEMPORARY TABLE.
+**
+** If AUTOVACUUM is enabled then it is possible that another root page
+** might be moved into the newly deleted root page in order to keep all
+** root pages contiguous at the beginning of the database.  The former
+** value of the root page that moved - its value before the move occurred -
+** is stored in register P2. If no page movement was required (because the
+** table being dropped was already the last one in the database) then a
+** zero is stored in register P2.  If AUTOVACUUM is disabled then a zero
+** is stored in register P2.
+**
+** This opcode throws an error if there are any active reader VMs when
+** it is invoked. This is done to avoid the difficulty associated with
+** updating existing cursors when a root page is moved in an AUTOVACUUM
+** database. This error is thrown even if the database is not an AUTOVACUUM
+** db in order to avoid introducing an incompatibility between autovacuum
+** and non-autovacuum modes.
+**
+** See also: Clear
+*/
+case OP_Destroy: {     /* out2 */
+  int iMoved;
+  int iDb;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  assert( p->readOnly==0 );
+  assert( pOp->p1>1 );
+  pOut = out2Prerelease(p, pOp);
+  pOut->flags = MEM_Null;
+  if( db->nVdbeRead > db->nVDestroy+1 ){
+    rc = SQLITE_LOCKED;
+    p->errorAction = OE_Abort;
+    goto abort_due_to_error;
+  }else{
+    iDb = pOp->p3;
+    assert( DbMaskTest(p->btreeMask, iDb) );
+    iMoved = 0;  /* Not needed.  Only to silence a warning. */
+    rc = sqlite3BtreeDropTable(db->aDb[iDb].pBt, pOp->p1, &iMoved);
+    pOut->flags = MEM_Int;
+    pOut->u.i = iMoved;
+    if( rc ) goto abort_due_to_error;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( iMoved!=0 ){
+      sqlite3RootPageMoved(db, iDb, iMoved, pOp->p1);
+      /* All OP_Destroy operations occur on the same btree */
+      assert( resetSchemaOnFault==0 || resetSchemaOnFault==iDb+1 );
+      resetSchemaOnFault = iDb+1;
+    }
+#endif
+  }
+  break;
+}
+
+/* Opcode: Clear P1 P2 P3
+**
+** Delete all contents of the database table or index whose root page
+** in the database file is given by P1.  But, unlike Destroy, do not
+** remove the table or index from the database file.
+**
+** The table being cleared is in the main database file if P2==0.  If
+** P2==1 then the table to be cleared is in the auxiliary database file
+** that is used to store tables create using CREATE TEMPORARY TABLE.
+**
+** If the P3 value is non-zero, then the row change count is incremented
+** by the number of rows in the table being cleared. If P3 is greater
+** than zero, then the value stored in register P3 is also incremented
+** by the number of rows in the table being cleared.
+**
+** See also: Destroy
+*/
+case OP_Clear: {
+  i64 nChange;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  nChange = 0;
+  assert( p->readOnly==0 );
+  assert( DbMaskTest(p->btreeMask, pOp->p2) );
+  rc = sqlite3BtreeClearTable(db->aDb[pOp->p2].pBt, (u32)pOp->p1, &nChange);
+  if( pOp->p3 ){
+    p->nChange += nChange;
+    if( pOp->p3>0 ){
+      assert( memIsValid(&aMem[pOp->p3]) );
+      memAboutToChange(p, &aMem[pOp->p3]);
+      aMem[pOp->p3].u.i += nChange;
+    }
+  }
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: ResetSorter P1 * * * *
+**
+** Delete all contents from the ephemeral table or sorter
+** that is open on cursor P1.
+**
+** This opcode only works for cursors used for sorting and
+** opened with OP_OpenEphemeral or OP_SorterOpen.
+*/
+case OP_ResetSorter: {
+  VdbeCursor *pC;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  if( isSorter(pC) ){
+    sqlite3VdbeSorterReset(db, pC->uc.pSorter);
+  }else{
+    assert( pC->eCurType==CURTYPE_BTREE );
+    assert( pC->isEphemeral );
+    rc = sqlite3BtreeClearTableOfCursor(pC->uc.pCursor);
+    if( rc ) goto abort_due_to_error;
+  }
+  break;
+}
+
+/* Opcode: CreateBtree P1 P2 P3 * *
+** Synopsis: r[P2]=root iDb=P1 flags=P3
+**
+** Allocate a new b-tree in the main database file if P1==0 or in the
+** TEMP database file if P1==1 or in an attached database if
+** P1>1.  The P3 argument must be 1 (BTREE_INTKEY) for a rowid table
+** it must be 2 (BTREE_BLOBKEY) for an index or WITHOUT ROWID table.
+** The root page number of the new b-tree is stored in register P2.
+*/
+case OP_CreateBtree: {          /* out2 */
+  Pgno pgno;
+  Db *pDb;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  pOut = out2Prerelease(p, pOp);
+  pgno = 0;
+  assert( pOp->p3==BTREE_INTKEY || pOp->p3==BTREE_BLOBKEY );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p1) );
+  assert( p->readOnly==0 );
+  pDb = &db->aDb[pOp->p1];
+  assert( pDb->pBt!=0 );
+  rc = sqlite3BtreeCreateTable(pDb->pBt, &pgno, pOp->p3);
+  if( rc ) goto abort_due_to_error;
+  pOut->u.i = pgno;
+  break;
+}
+
+/* Opcode: SqlExec P1 P2 * P4 *
+**
+** Run the SQL statement or statements specified in the P4 string.
+**
+** The P1 parameter is a bitmask of options:
+**
+**    0x0001     Disable Auth and Trace callbacks while the statements
+**               in P4 are running.
+**
+**    0x0002     Set db->nAnalysisLimit to P2 while the statements in
+**               P4 are running.
+**
+*/
+case OP_SqlExec: {
+  char *zErr;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth;
+#endif
+  u8 mTrace;
+  int savedAnalysisLimit;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  db->nSqlExec++;
+  zErr = 0;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  xAuth = db->xAuth;
+#endif
+  mTrace = db->mTrace;
+  savedAnalysisLimit = db->nAnalysisLimit;
+  if( pOp->p1 & 0x0001 ){
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    db->xAuth = 0;
+#endif
+    db->mTrace = 0;
+  }
+  if( pOp->p1 & 0x0002 ){
+    db->nAnalysisLimit = pOp->p2;
+  }
+  rc = sqlite3_exec(db, pOp->p4.z, 0, 0, &zErr);
+  db->nSqlExec--;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+  db->mTrace = mTrace;
+  db->nAnalysisLimit = savedAnalysisLimit;
+  if( zErr || rc ){
+    sqlite3VdbeError(p, "%s", zErr);
+    sqlite3_free(zErr);
+    if( rc==SQLITE_NOMEM ) goto no_mem;
+    goto abort_due_to_error;
+  }
+  break;
+}
+
+/* Opcode: ParseSchema P1 * * P4 *
+**
+** Read and parse all entries from the schema table of database P1
+** that match the WHERE clause P4.  If P4 is a NULL pointer, then the
+** entire schema for P1 is reparsed.
+**
+** This opcode invokes the parser to create a new virtual machine,
+** then runs the new virtual machine.  It is thus a re-entrant opcode.
+*/
+case OP_ParseSchema: {
+  int iDb;
+  const char *zSchema;
+  char *zSql;
+  InitData initData;
+
+  /* Any prepared statement that invokes this opcode will hold mutexes
+  ** on every btree.  This is a prerequisite for invoking
+  ** sqlite3InitCallback().
+  */
+#ifdef SQLITE_DEBUG
+  for(iDb=0; iDb<db->nDb; iDb++){
+    assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
+  }
+#endif
+
+  iDb = pOp->p1;
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( DbHasProperty(db, iDb, DB_SchemaLoaded)
+           || db->mallocFailed
+           || (CORRUPT_DB && (db->flags & SQLITE_NoSchemaError)!=0) );
+
+#ifndef SQLITE_OMIT_ALTERTABLE
+  if( pOp->p4.z==0 ){
+    sqlite3SchemaClear(db->aDb[iDb].pSchema);
+    db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
+    rc = sqlite3InitOne(db, iDb, &p->zErrMsg, pOp->p5);
+    db->mDbFlags |= DBFLAG_SchemaChange;
+    p->expired = 0;
+  }else
+#endif
+  {
+    zSchema = LEGACY_SCHEMA_TABLE;
+    initData.db = db;
+    initData.iDb = iDb;
+    initData.pzErrMsg = &p->zErrMsg;
+    initData.mInitFlags = 0;
+    initData.mxPage = sqlite3BtreeLastPage(db->aDb[iDb].pBt);
+    zSql = sqlite3MPrintf(db,
+       "SELECT*FROM\"%w\".%s WHERE %s ORDER BY rowid",
+       db->aDb[iDb].zDbSName, zSchema, pOp->p4.z);
+    if( zSql==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      assert( db->init.busy==0 );
+      db->init.busy = 1;
+      initData.rc = SQLITE_OK;
+      initData.nInitRow = 0;
+      assert( !db->mallocFailed );
+      rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
+      if( rc==SQLITE_OK ) rc = initData.rc;
+      if( rc==SQLITE_OK && initData.nInitRow==0 ){
+        /* The OP_ParseSchema opcode with a non-NULL P4 argument should parse
+        ** at least one SQL statement. Any less than that indicates that
+        ** the sqlite_schema table is corrupt. */
+        rc = SQLITE_CORRUPT_BKPT;
+      }
+      sqlite3DbFreeNN(db, zSql);
+      db->init.busy = 0;
+    }
+  }
+  if( rc ){
+    sqlite3ResetAllSchemasOfConnection(db);
+    if( rc==SQLITE_NOMEM ){
+      goto no_mem;
+    }
+    goto abort_due_to_error;
+  }
+  break;
+}
+
+#if !defined(SQLITE_OMIT_ANALYZE)
+/* Opcode: LoadAnalysis P1 * * * *
+**
+** Read the sqlite_stat1 table for database P1 and load the content
+** of that table into the internal index hash table.  This will cause
+** the analysis to be used when preparing all subsequent queries.
+*/
+case OP_LoadAnalysis: {
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  rc = sqlite3AnalysisLoad(db, pOp->p1);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* !defined(SQLITE_OMIT_ANALYZE) */
+
+/* Opcode: DropTable P1 * * P4 *
+**
+** Remove the internal (in-memory) data structures that describe
+** the table named P4 in database P1.  This is called after a table
+** is dropped from disk (using the Destroy opcode) in order to keep
+** the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropTable: {
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  sqlite3UnlinkAndDeleteTable(db, pOp->p1, pOp->p4.z);
+  break;
+}
+
+/* Opcode: DropIndex P1 * * P4 *
+**
+** Remove the internal (in-memory) data structures that describe
+** the index named P4 in database P1.  This is called after an index
+** is dropped from disk (using the Destroy opcode)
+** in order to keep the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropIndex: {
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  sqlite3UnlinkAndDeleteIndex(db, pOp->p1, pOp->p4.z);
+  break;
+}
+
+/* Opcode: DropTrigger P1 * * P4 *
+**
+** Remove the internal (in-memory) data structures that describe
+** the trigger named P4 in database P1.  This is called after a trigger
+** is dropped from disk (using the Destroy opcode) in order to keep
+** the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropTrigger: {
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  sqlite3UnlinkAndDeleteTrigger(db, pOp->p1, pOp->p4.z);
+  break;
+}
+
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/* Opcode: IntegrityCk P1 P2 P3 P4 P5
+**
+** Do an analysis of the currently open database.  Store in
+** register (P1+1) the text of an error message describing any problems.
+** If no problems are found, store a NULL in register (P1+1).
+**
+** The register (P1) contains one less than the maximum number of allowed
+** errors.  At most reg(P1) errors will be reported.
+** In other words, the analysis stops as soon as reg(P1) errors are
+** seen.  Reg(P1) is updated with the number of errors remaining.
+**
+** The root page numbers of all tables in the database are integers
+** stored in P4_INTARRAY argument.
+**
+** If P5 is not zero, the check is done on the auxiliary database
+** file, not the main database file.
+**
+** This opcode is used to implement the integrity_check pragma.
+*/
+case OP_IntegrityCk: {
+  int nRoot;      /* Number of tables to check.  (Number of root pages.) */
+  Pgno *aRoot;    /* Array of rootpage numbers for tables to be checked */
+  int nErr;       /* Number of errors reported */
+  char *z;        /* Text of the error report */
+  Mem *pnErr;     /* Register keeping track of errors remaining */
+
+  assert( p->bIsReader );
+  assert( pOp->p4type==P4_INTARRAY );
+  nRoot = pOp->p2;
+  aRoot = pOp->p4.ai;
+  assert( nRoot>0 );
+  assert( aRoot!=0 );
+  assert( aRoot[0]==(Pgno)nRoot );
+  assert( pOp->p1>0 && (pOp->p1+1)<=(p->nMem+1 - p->nCursor) );
+  pnErr = &aMem[pOp->p1];
+  assert( (pnErr->flags & MEM_Int)!=0 );
+  assert( (pnErr->flags & (MEM_Str|MEM_Blob))==0 );
+  pIn1 = &aMem[pOp->p1+1];
+  assert( pOp->p5<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p5) );
+  rc = sqlite3BtreeIntegrityCheck(db, db->aDb[pOp->p5].pBt, &aRoot[1],
+      &aMem[pOp->p3], nRoot, (int)pnErr->u.i+1, &nErr, &z);
+  sqlite3VdbeMemSetNull(pIn1);
+  if( nErr==0 ){
+    assert( z==0 );
+  }else if( rc ){
+    sqlite3_free(z);
+    goto abort_due_to_error;
+  }else{
+    pnErr->u.i -= nErr-1;
+    sqlite3VdbeMemSetStr(pIn1, z, -1, SQLITE_UTF8, sqlite3_free);
+  }
+  UPDATE_MAX_BLOBSIZE(pIn1);
+  sqlite3VdbeChangeEncoding(pIn1, encoding);
+  goto check_for_interrupt;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+/* Opcode: RowSetAdd P1 P2 * * *
+** Synopsis: rowset(P1)=r[P2]
+**
+** Insert the integer value held by register P2 into a RowSet object
+** held in register P1.
+**
+** An assertion fails if P2 is not an integer.
+*/
+case OP_RowSetAdd: {       /* in1, in2 */
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  assert( (pIn2->flags & MEM_Int)!=0 );
+  if( (pIn1->flags & MEM_Blob)==0 ){
+    if( sqlite3VdbeMemSetRowSet(pIn1) ) goto no_mem;
+  }
+  assert( sqlite3VdbeMemIsRowSet(pIn1) );
+  sqlite3RowSetInsert((RowSet*)pIn1->z, pIn2->u.i);
+  break;
+}
+
+/* Opcode: RowSetRead P1 P2 P3 * *
+** Synopsis: r[P3]=rowset(P1)
+**
+** Extract the smallest value from the RowSet object in P1
+** and put that value into register P3.
+** Or, if RowSet object P1 is initially empty, leave P3
+** unchanged and jump to instruction P2.
+*/
+case OP_RowSetRead: {       /* jump, in1, out3 */
+  i64 val;
+
+  pIn1 = &aMem[pOp->p1];
+  assert( (pIn1->flags & MEM_Blob)==0 || sqlite3VdbeMemIsRowSet(pIn1) );
+  if( (pIn1->flags & MEM_Blob)==0
+   || sqlite3RowSetNext((RowSet*)pIn1->z, &val)==0
+  ){
+    /* The boolean index is empty */
+    sqlite3VdbeMemSetNull(pIn1);
+    VdbeBranchTaken(1,2);
+    goto jump_to_p2_and_check_for_interrupt;
+  }else{
+    /* A value was pulled from the index */
+    VdbeBranchTaken(0,2);
+    sqlite3VdbeMemSetInt64(&aMem[pOp->p3], val);
+  }
+  goto check_for_interrupt;
+}
+
+/* Opcode: RowSetTest P1 P2 P3 P4
+** Synopsis: if r[P3] in rowset(P1) goto P2
+**
+** Register P3 is assumed to hold a 64-bit integer value. If register P1
+** contains a RowSet object and that RowSet object contains
+** the value held in P3, jump to register P2. Otherwise, insert the
+** integer in P3 into the RowSet and continue on to the
+** next opcode.
+**
+** The RowSet object is optimized for the case where sets of integers
+** are inserted in distinct phases, which each set contains no duplicates.
+** Each set is identified by a unique P4 value. The first set
+** must have P4==0, the final set must have P4==-1, and for all other sets
+** must have P4>0.
+**
+** This allows optimizations: (a) when P4==0 there is no need to test
+** the RowSet object for P3, as it is guaranteed not to contain it,
+** (b) when P4==-1 there is no need to insert the value, as it will
+** never be tested for, and (c) when a value that is part of set X is
+** inserted, there is no need to search to see if the same value was
+** previously inserted as part of set X (only if it was previously
+** inserted as part of some other set).
+*/
+case OP_RowSetTest: {                     /* jump, in1, in3 */
+  int iSet;
+  int exists;
+
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
+  iSet = pOp->p4.i;
+  assert( pIn3->flags&MEM_Int );
+
+  /* If there is anything other than a rowset object in memory cell P1,
+  ** delete it now and initialize P1 with an empty rowset
+  */
+  if( (pIn1->flags & MEM_Blob)==0 ){
+    if( sqlite3VdbeMemSetRowSet(pIn1) ) goto no_mem;
+  }
+  assert( sqlite3VdbeMemIsRowSet(pIn1) );
+  assert( pOp->p4type==P4_INT32 );
+  assert( iSet==-1 || iSet>=0 );
+  if( iSet ){
+    exists = sqlite3RowSetTest((RowSet*)pIn1->z, iSet, pIn3->u.i);
+    VdbeBranchTaken(exists!=0,2);
+    if( exists ) goto jump_to_p2;
+  }
+  if( iSet>=0 ){
+    sqlite3RowSetInsert((RowSet*)pIn1->z, pIn3->u.i);
+  }
+  break;
+}
+
+
+#ifndef SQLITE_OMIT_TRIGGER
+
+/* Opcode: Program P1 P2 P3 P4 P5
+**
+** Execute the trigger program passed as P4 (type P4_SUBPROGRAM).
+**
+** P1 contains the address of the memory cell that contains the first memory
+** cell in an array of values used as arguments to the sub-program. P2
+** contains the address to jump to if the sub-program throws an IGNORE
+** exception using the RAISE() function. P2 might be zero, if there is
+** no possibility that an IGNORE exception will be raised.
+** Register P3 contains the address
+** of a memory cell in this (the parent) VM that is used to allocate the
+** memory required by the sub-vdbe at runtime.
+**
+** P4 is a pointer to the VM containing the trigger program.
+**
+** If P5 is non-zero, then recursive program invocation is enabled.
+*/
+case OP_Program: {        /* jump0 */
+  int nMem;               /* Number of memory registers for sub-program */
+  int nByte;              /* Bytes of runtime space required for sub-program */
+  Mem *pRt;               /* Register to allocate runtime space */
+  Mem *pMem;              /* Used to iterate through memory cells */
+  Mem *pEnd;              /* Last memory cell in new array */
+  VdbeFrame *pFrame;      /* New vdbe frame to execute in */
+  SubProgram *pProgram;   /* Sub-program to execute */
+  void *t;                /* Token identifying trigger */
+
+  pProgram = pOp->p4.pProgram;
+  pRt = &aMem[pOp->p3];
+  assert( pProgram->nOp>0 );
+
+  /* If the p5 flag is clear, then recursive invocation of triggers is
+  ** disabled for backwards compatibility (p5 is set if this sub-program
+  ** is really a trigger, not a foreign key action, and the flag set
+  ** and cleared by the "PRAGMA recursive_triggers" command is clear).
+  **
+  ** It is recursive invocation of triggers, at the SQL level, that is
+  ** disabled. In some cases a single trigger may generate more than one
+  ** SubProgram (if the trigger may be executed with more than one different
+  ** ON CONFLICT algorithm). SubProgram structures associated with a
+  ** single trigger all have the same value for the SubProgram.token
+  ** variable.  */
+  if( pOp->p5 ){
+    t = pProgram->token;
+    for(pFrame=p->pFrame; pFrame && pFrame->token!=t; pFrame=pFrame->pParent);
+    if( pFrame ) break;
+  }
+
+  if( p->nFrame>=db->aLimit[SQLITE_LIMIT_TRIGGER_DEPTH] ){
+    rc = SQLITE_ERROR;
+    sqlite3VdbeError(p, "too many levels of trigger recursion");
+    goto abort_due_to_error;
+  }
+
+  /* Register pRt is used to store the memory required to save the state
+  ** of the current program, and the memory required at runtime to execute
+  ** the trigger program. If this trigger has been fired before, then pRt
+  ** is already allocated. Otherwise, it must be initialized.  */
+  if( (pRt->flags&MEM_Blob)==0 ){
+    /* SubProgram.nMem is set to the number of memory cells used by the
+    ** program stored in SubProgram.aOp. As well as these, one memory
+    ** cell is required for each cursor used by the program. Set local
+    ** variable nMem (and later, VdbeFrame.nChildMem) to this value.
+    */
+    nMem = pProgram->nMem + pProgram->nCsr;
+    assert( nMem>0 );
+    if( pProgram->nCsr==0 ) nMem++;
+    nByte = ROUND8(sizeof(VdbeFrame))
+              + nMem * sizeof(Mem)
+              + pProgram->nCsr * sizeof(VdbeCursor*)
+              + (pProgram->nOp + 7)/8;
+    pFrame = sqlite3DbMallocZero(db, nByte);
+    if( !pFrame ){
+      goto no_mem;
+    }
+    sqlite3VdbeMemRelease(pRt);
+    pRt->flags = MEM_Blob|MEM_Dyn;
+    pRt->z = (char*)pFrame;
+    pRt->n = nByte;
+    pRt->xDel = sqlite3VdbeFrameMemDel;
+
+    pFrame->v = p;
+    pFrame->nChildMem = nMem;
+    pFrame->nChildCsr = pProgram->nCsr;
+    pFrame->pc = (int)(pOp - aOp);
+    pFrame->aMem = p->aMem;
+    pFrame->nMem = p->nMem;
+    pFrame->apCsr = p->apCsr;
+    pFrame->nCursor = p->nCursor;
+    pFrame->aOp = p->aOp;
+    pFrame->nOp = p->nOp;
+    pFrame->token = pProgram->token;
+#ifdef SQLITE_DEBUG
+    pFrame->iFrameMagic = SQLITE_FRAME_MAGIC;
+#endif
+
+    pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
+    for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
+      pMem->flags = MEM_Undefined;
+      pMem->db = db;
+    }
+  }else{
+    pFrame = (VdbeFrame*)pRt->z;
+    assert( pRt->xDel==sqlite3VdbeFrameMemDel );
+    assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem
+        || (pProgram->nCsr==0 && pProgram->nMem+1==pFrame->nChildMem) );
+    assert( pProgram->nCsr==pFrame->nChildCsr );
+    assert( (int)(pOp - aOp)==pFrame->pc );
+  }
+
+  p->nFrame++;
+  pFrame->pParent = p->pFrame;
+  pFrame->lastRowid = db->lastRowid;
+  pFrame->nChange = p->nChange;
+  pFrame->nDbChange = p->db->nChange;
+  assert( pFrame->pAuxData==0 );
+  pFrame->pAuxData = p->pAuxData;
+  p->pAuxData = 0;
+  p->nChange = 0;
+  p->pFrame = pFrame;
+  p->aMem = aMem = VdbeFrameMem(pFrame);
+  p->nMem = pFrame->nChildMem;
+  p->nCursor = (u16)pFrame->nChildCsr;
+  p->apCsr = (VdbeCursor **)&aMem[p->nMem];
+  pFrame->aOnce = (u8*)&p->apCsr[pProgram->nCsr];
+  memset(pFrame->aOnce, 0, (pProgram->nOp + 7)/8);
+  p->aOp = aOp = pProgram->aOp;
+  p->nOp = pProgram->nOp;
+#ifdef SQLITE_DEBUG
+  /* Verify that second and subsequent executions of the same trigger do not
+  ** try to reuse register values from the first use. */
+  {
+    int i;
+    for(i=0; i<p->nMem; i++){
+      aMem[i].pScopyFrom = 0;  /* Prevent false-positive AboutToChange() errs */
+      MemSetTypeFlag(&aMem[i], MEM_Undefined); /* Fault if this reg is reused */
+    }
+  }
+#endif
+  pOp = &aOp[-1];
+  goto check_for_interrupt;
+}
+
+/* Opcode: Param P1 P2 * * *
+**
+** This opcode is only ever present in sub-programs called via the
+** OP_Program instruction. Copy a value currently stored in a memory
+** cell of the calling (parent) frame to cell P2 in the current frames
+** address space. This is used by trigger programs to access the new.*
+** and old.* values.
+**
+** The address of the cell in the parent frame is determined by adding
+** the value of the P1 argument to the value of the P1 argument to the
+** calling OP_Program instruction.
+*/
+case OP_Param: {           /* out2 */
+  VdbeFrame *pFrame;
+  Mem *pIn;
+  pOut = out2Prerelease(p, pOp);
+  pFrame = p->pFrame;
+  pIn = &pFrame->aMem[pOp->p1 + pFrame->aOp[pFrame->pc].p1];
+  sqlite3VdbeMemShallowCopy(pOut, pIn, MEM_Ephem);
+  break;
+}
+
+#endif /* #ifndef SQLITE_OMIT_TRIGGER */
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+/* Opcode: FkCounter P1 P2 * * *
+** Synopsis: fkctr[P1]+=P2
+**
+** Increment a "constraint counter" by P2 (P2 may be negative or positive).
+** If P1 is non-zero, the database constraint counter is incremented
+** (deferred foreign key constraints). Otherwise, if P1 is zero, the
+** statement counter is incremented (immediate foreign key constraints).
+*/
+case OP_FkCounter: {
+  if( db->flags & SQLITE_DeferFKs ){
+    db->nDeferredImmCons += pOp->p2;
+  }else if( pOp->p1 ){
+    db->nDeferredCons += pOp->p2;
+  }else{
+    p->nFkConstraint += pOp->p2;
+  }
+  break;
+}
+
+/* Opcode: FkIfZero P1 P2 * * *
+** Synopsis: if fkctr[P1]==0 goto P2
+**
+** This opcode tests if a foreign key constraint-counter is currently zero.
+** If so, jump to instruction P2. Otherwise, fall through to the next
+** instruction.
+**
+** If P1 is non-zero, then the jump is taken if the database constraint-counter
+** is zero (the one that counts deferred constraint violations). If P1 is
+** zero, the jump is taken if the statement constraint-counter is zero
+** (immediate foreign key constraint violations).
+*/
+case OP_FkIfZero: {         /* jump */
+  if( pOp->p1 ){
+    VdbeBranchTaken(db->nDeferredCons==0 && db->nDeferredImmCons==0, 2);
+    if( db->nDeferredCons==0 && db->nDeferredImmCons==0 ) goto jump_to_p2;
+  }else{
+    VdbeBranchTaken(p->nFkConstraint==0 && db->nDeferredImmCons==0, 2);
+    if( p->nFkConstraint==0 && db->nDeferredImmCons==0 ) goto jump_to_p2;
+  }
+  break;
+}
+#endif /* #ifndef SQLITE_OMIT_FOREIGN_KEY */
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+/* Opcode: MemMax P1 P2 * * *
+** Synopsis: r[P1]=max(r[P1],r[P2])
+**
+** P1 is a register in the root frame of this VM (the root frame is
+** different from the current frame if this instruction is being executed
+** within a sub-program). Set the value of register P1 to the maximum of
+** its current value and the value in register P2.
+**
+** This instruction throws an error if the memory cell is not initially
+** an integer.
+*/
+case OP_MemMax: {        /* in2 */
+  VdbeFrame *pFrame;
+  if( p->pFrame ){
+    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
+    pIn1 = &pFrame->aMem[pOp->p1];
+  }else{
+    pIn1 = &aMem[pOp->p1];
+  }
+  assert( memIsValid(pIn1) );
+  sqlite3VdbeMemIntegerify(pIn1);
+  pIn2 = &aMem[pOp->p2];
+  sqlite3VdbeMemIntegerify(pIn2);
+  if( pIn1->u.i<pIn2->u.i){
+    pIn1->u.i = pIn2->u.i;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_AUTOINCREMENT */
+
+/* Opcode: IfPos P1 P2 P3 * *
+** Synopsis: if r[P1]>0 then r[P1]-=P3, goto P2
+**
+** Register P1 must contain an integer.
+** If the value of register P1 is 1 or greater, subtract P3 from the
+** value in P1 and jump to P2.
+**
+** If the initial value of register P1 is less than 1, then the
+** value is unchanged and control passes through to the next instruction.
+*/
+case OP_IfPos: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags&MEM_Int );
+  VdbeBranchTaken( pIn1->u.i>0, 2);
+  if( pIn1->u.i>0 ){
+    pIn1->u.i -= pOp->p3;
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: OffsetLimit P1 P2 P3 * *
+** Synopsis: if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1)
+**
+** This opcode performs a commonly used computation associated with
+** LIMIT and OFFSET processing.  r[P1] holds the limit counter.  r[P3]
+** holds the offset counter.  The opcode computes the combined value
+** of the LIMIT and OFFSET and stores that value in r[P2].  The r[P2]
+** value computed is the total number of rows that will need to be
+** visited in order to complete the query.
+**
+** If r[P3] is zero or negative, that means there is no OFFSET
+** and r[P2] is set to be the value of the LIMIT, r[P1].
+**
+** if r[P1] is zero or negative, that means there is no LIMIT
+** and r[P2] is set to -1.
+**
+** Otherwise, r[P2] is set to the sum of r[P1] and r[P3].
+*/
+case OP_OffsetLimit: {    /* in1, out2, in3 */
+  i64 x;
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
+  pOut = out2Prerelease(p, pOp);
+  assert( pIn1->flags & MEM_Int );
+  assert( pIn3->flags & MEM_Int );
+  x = pIn1->u.i;
+  if( x<=0 || sqlite3AddInt64(&x, pIn3->u.i>0?pIn3->u.i:0) ){
+    /* If the LIMIT is less than or equal to zero, loop forever.  This
+    ** is documented.  But also, if the LIMIT+OFFSET exceeds 2^63 then
+    ** also loop forever.  This is undocumented.  In fact, one could argue
+    ** that the loop should terminate.  But assuming 1 billion iterations
+    ** per second (far exceeding the capabilities of any current hardware)
+    ** it would take nearly 300 years to actually reach the limit.  So
+    ** looping forever is a reasonable approximation. */
+    pOut->u.i = -1;
+  }else{
+    pOut->u.i = x;
+  }
+  break;
+}
+
+/* Opcode: IfNotZero P1 P2 * * *
+** Synopsis: if r[P1]!=0 then r[P1]--, goto P2
+**
+** Register P1 must contain an integer.  If the content of register P1 is
+** initially greater than zero, then decrement the value in register P1.
+** If it is non-zero (negative or positive) and then also jump to P2.
+** If register P1 is initially zero, leave it unchanged and fall through.
+*/
+case OP_IfNotZero: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags&MEM_Int );
+  VdbeBranchTaken(pIn1->u.i<0, 2);
+  if( pIn1->u.i ){
+     if( pIn1->u.i>0 ) pIn1->u.i--;
+     goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: DecrJumpZero P1 P2 * * *
+** Synopsis: if (--r[P1])==0 goto P2
+**
+** Register P1 must hold an integer.  Decrement the value in P1
+** and jump to P2 if the new value is exactly zero.
+*/
+case OP_DecrJumpZero: {      /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags&MEM_Int );
+  if( pIn1->u.i>SMALLEST_INT64 ) pIn1->u.i--;
+  VdbeBranchTaken(pIn1->u.i==0, 2);
+  if( pIn1->u.i==0 ) goto jump_to_p2;
+  break;
+}
+
+
+/* Opcode: AggStep * P2 P3 P4 P5
+** Synopsis: accum=r[P3] step(r[P2@P5])
+**
+** Execute the xStep function for an aggregate.
+** The function has P5 arguments.  P4 is a pointer to the
+** FuncDef structure that specifies the function.  Register P3 is the
+** accumulator.
+**
+** The P5 arguments are taken from register P2 and its
+** successors.
+*/
+/* Opcode: AggInverse * P2 P3 P4 P5
+** Synopsis: accum=r[P3] inverse(r[P2@P5])
+**
+** Execute the xInverse function for an aggregate.
+** The function has P5 arguments.  P4 is a pointer to the
+** FuncDef structure that specifies the function.  Register P3 is the
+** accumulator.
+**
+** The P5 arguments are taken from register P2 and its
+** successors.
+*/
+/* Opcode: AggStep1 P1 P2 P3 P4 P5
+** Synopsis: accum=r[P3] step(r[P2@P5])
+**
+** Execute the xStep (if P1==0) or xInverse (if P1!=0) function for an
+** aggregate.  The function has P5 arguments.  P4 is a pointer to the
+** FuncDef structure that specifies the function.  Register P3 is the
+** accumulator.
+**
+** The P5 arguments are taken from register P2 and its
+** successors.
+**
+** This opcode is initially coded as OP_AggStep0.  On first evaluation,
+** the FuncDef stored in P4 is converted into an sqlite3_context and
+** the opcode is changed.  In this way, the initialization of the
+** sqlite3_context only happens once, instead of on each call to the
+** step function.
+*/
+case OP_AggInverse:
+case OP_AggStep: {
+  int n;
+  sqlite3_context *pCtx;
+  u64 nAlloc;
+
+  assert( pOp->p4type==P4_FUNCDEF );
+  n = pOp->p5;
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem+1 - p->nCursor)+1) );
+  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
+
+  /* Allocate space for (a) the context object and (n-1) extra pointers
+  ** to append to the sqlite3_context.argv[1] array, and (b) a memory
+  ** cell in which to store the accumulation. Be careful that the memory
+  ** cell is 8-byte aligned, even on platforms where a pointer is 32-bits.
+  **
+  ** Note: We could avoid this by using a regular memory cell from aMem[] for
+  ** the accumulator, instead of allocating one here. */
+  nAlloc = ROUND8P( sizeof(pCtx[0]) + (n-1)*sizeof(sqlite3_value*) );
+  pCtx = sqlite3DbMallocRawNN(db, nAlloc + sizeof(Mem));
+  if( pCtx==0 ) goto no_mem;
+  pCtx->pOut = (Mem*)((u8*)pCtx + nAlloc);
+  assert( EIGHT_BYTE_ALIGNMENT(pCtx->pOut) );
+
+  sqlite3VdbeMemInit(pCtx->pOut, db, MEM_Null);
+  pCtx->pMem = 0;
+  pCtx->pFunc = pOp->p4.pFunc;
+  pCtx->iOp = (int)(pOp - aOp);
+  pCtx->pVdbe = p;
+  pCtx->skipFlag = 0;
+  pCtx->isError = 0;
+  pCtx->enc = encoding;
+  pCtx->argc = n;
+  pOp->p4type = P4_FUNCCTX;
+  pOp->p4.pCtx = pCtx;
+
+  /* OP_AggInverse must have P1==1 and OP_AggStep must have P1==0 */
+  assert( pOp->p1==(pOp->opcode==OP_AggInverse) );
+
+  pOp->opcode = OP_AggStep1;
+  /* Fall through into OP_AggStep */
+  /* no break */ deliberate_fall_through
+}
+case OP_AggStep1: {
+  int i;
+  sqlite3_context *pCtx;
+  Mem *pMem;
+
+  assert( pOp->p4type==P4_FUNCCTX );
+  pCtx = pOp->p4.pCtx;
+  pMem = &aMem[pOp->p3];
+
+#ifdef SQLITE_DEBUG
+  if( pOp->p1 ){
+    /* This is an OP_AggInverse call.  Verify that xStep has always
+    ** been called at least once prior to any xInverse call. */
+    assert( pMem->uTemp==0x1122e0e3 );
+  }else{
+    /* This is an OP_AggStep call.  Mark it as such. */
+    pMem->uTemp = 0x1122e0e3;
+  }
+#endif
+
+  /* If this function is inside of a trigger, the register array in aMem[]
+  ** might change from one evaluation to the next.  The next block of code
+  ** checks to see if the register array has changed, and if so it
+  ** reinitializes the relevant parts of the sqlite3_context object */
+  if( pCtx->pMem != pMem ){
+    pCtx->pMem = pMem;
+    for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
+  }
+
+#ifdef SQLITE_DEBUG
+  for(i=0; i<pCtx->argc; i++){
+    assert( memIsValid(pCtx->argv[i]) );
+    REGISTER_TRACE(pOp->p2+i, pCtx->argv[i]);
+  }
+#endif
+
+  pMem->n++;
+  assert( pCtx->pOut->flags==MEM_Null );
+  assert( pCtx->isError==0 );
+  assert( pCtx->skipFlag==0 );
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( pOp->p1 ){
+    (pCtx->pFunc->xInverse)(pCtx,pCtx->argc,pCtx->argv);
+  }else
+#endif
+  (pCtx->pFunc->xSFunc)(pCtx,pCtx->argc,pCtx->argv); /* IMP: R-24505-23230 */
+
+  if( pCtx->isError ){
+    if( pCtx->isError>0 ){
+      sqlite3VdbeError(p, "%s", sqlite3_value_text(pCtx->pOut));
+      rc = pCtx->isError;
+    }
+    if( pCtx->skipFlag ){
+      assert( pOp[-1].opcode==OP_CollSeq );
+      i = pOp[-1].p1;
+      if( i ) sqlite3VdbeMemSetInt64(&aMem[i], 1);
+      pCtx->skipFlag = 0;
+    }
+    sqlite3VdbeMemRelease(pCtx->pOut);
+    pCtx->pOut->flags = MEM_Null;
+    pCtx->isError = 0;
+    if( rc ) goto abort_due_to_error;
+  }
+  assert( pCtx->pOut->flags==MEM_Null );
+  assert( pCtx->skipFlag==0 );
+  break;
+}
+
+/* Opcode: AggFinal P1 P2 * P4 *
+** Synopsis: accum=r[P1] N=P2
+**
+** P1 is the memory location that is the accumulator for an aggregate
+** or window function.  Execute the finalizer function
+** for an aggregate and store the result in P1.
+**
+** P2 is the number of arguments that the step function takes and
+** P4 is a pointer to the FuncDef for this function.  The P2
+** argument is not used by this opcode.  It is only there to disambiguate
+** functions that can take varying numbers of arguments.  The
+** P4 argument is only needed for the case where
+** the step function was not previously called.
+*/
+/* Opcode: AggValue * P2 P3 P4 *
+** Synopsis: r[P3]=value N=P2
+**
+** Invoke the xValue() function and store the result in register P3.
+**
+** P2 is the number of arguments that the step function takes and
+** P4 is a pointer to the FuncDef for this function.  The P2
+** argument is not used by this opcode.  It is only there to disambiguate
+** functions that can take varying numbers of arguments.  The
+** P4 argument is only needed for the case where
+** the step function was not previously called.
+*/
+case OP_AggValue:
+case OP_AggFinal: {
+  Mem *pMem;
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  assert( pOp->p3==0 || pOp->opcode==OP_AggValue );
+  pMem = &aMem[pOp->p1];
+  assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( pOp->p3 ){
+    memAboutToChange(p, &aMem[pOp->p3]);
+    rc = sqlite3VdbeMemAggValue(pMem, &aMem[pOp->p3], pOp->p4.pFunc);
+    pMem = &aMem[pOp->p3];
+  }else
+#endif
+  {
+    rc = sqlite3VdbeMemFinalize(pMem, pOp->p4.pFunc);
+  }
+
+  if( rc ){
+    sqlite3VdbeError(p, "%s", sqlite3_value_text(pMem));
+    goto abort_due_to_error;
+  }
+  sqlite3VdbeChangeEncoding(pMem, encoding);
+  UPDATE_MAX_BLOBSIZE(pMem);
+  REGISTER_TRACE((int)(pMem-aMem), pMem);
+  break;
+}
+
+#ifndef SQLITE_OMIT_WAL
+/* Opcode: Checkpoint P1 P2 P3 * *
+**
+** Checkpoint database P1. This is a no-op if P1 is not currently in
+** WAL mode. Parameter P2 is one of SQLITE_CHECKPOINT_PASSIVE, FULL,
+** RESTART, or TRUNCATE.  Write 1 or 0 into mem[P3] if the checkpoint returns
+** SQLITE_BUSY or not, respectively.  Write the number of pages in the
+** WAL after the checkpoint into mem[P3+1] and the number of pages
+** in the WAL that have been checkpointed after the checkpoint
+** completes into mem[P3+2].  However on an error, mem[P3+1] and
+** mem[P3+2] are initialized to -1.
+*/
+case OP_Checkpoint: {
+  int i;                          /* Loop counter */
+  int aRes[3];                    /* Results */
+  Mem *pMem;                      /* Write results here */
+
+  assert( p->readOnly==0 );
+  aRes[0] = 0;
+  aRes[1] = aRes[2] = -1;
+  assert( pOp->p2==SQLITE_CHECKPOINT_PASSIVE
+       || pOp->p2==SQLITE_CHECKPOINT_FULL
+       || pOp->p2==SQLITE_CHECKPOINT_RESTART
+       || pOp->p2==SQLITE_CHECKPOINT_TRUNCATE
+  );
+  rc = sqlite3Checkpoint(db, pOp->p1, pOp->p2, &aRes[1], &aRes[2]);
+  if( rc ){
+    if( rc!=SQLITE_BUSY ) goto abort_due_to_error;
+    rc = SQLITE_OK;
+    aRes[0] = 1;
+  }
+  for(i=0, pMem = &aMem[pOp->p3]; i<3; i++, pMem++){
+    sqlite3VdbeMemSetInt64(pMem, (i64)aRes[i]);
+  }
+  break;
+};
+#endif
+
+#ifndef SQLITE_OMIT_PRAGMA
+/* Opcode: JournalMode P1 P2 P3 * *
+**
+** Change the journal mode of database P1 to P3. P3 must be one of the
+** PAGER_JOURNALMODE_XXX values. If changing between the various rollback
+** modes (delete, truncate, persist, off and memory), this is a simple
+** operation. No IO is required.
+**
+** If changing into or out of WAL mode the procedure is more complicated.
+**
+** Write a string containing the final journal-mode to register P2.
+*/
+case OP_JournalMode: {    /* out2 */
+  Btree *pBt;                     /* Btree to change journal mode of */
+  Pager *pPager;                  /* Pager associated with pBt */
+  int eNew;                       /* New journal mode */
+  int eOld;                       /* The old journal mode */
+#ifndef SQLITE_OMIT_WAL
+  const char *zFilename;          /* Name of database file for pPager */
+#endif
+
+  pOut = out2Prerelease(p, pOp);
+  eNew = pOp->p3;
+  assert( eNew==PAGER_JOURNALMODE_DELETE
+       || eNew==PAGER_JOURNALMODE_TRUNCATE
+       || eNew==PAGER_JOURNALMODE_PERSIST
+       || eNew==PAGER_JOURNALMODE_OFF
+       || eNew==PAGER_JOURNALMODE_MEMORY
+       || eNew==PAGER_JOURNALMODE_WAL
+       || eNew==PAGER_JOURNALMODE_QUERY
+  );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( p->readOnly==0 );
+
+  pBt = db->aDb[pOp->p1].pBt;
+  pPager = sqlite3BtreePager(pBt);
+  eOld = sqlite3PagerGetJournalMode(pPager);
+  if( eNew==PAGER_JOURNALMODE_QUERY ) eNew = eOld;
+  assert( sqlite3BtreeHoldsMutex(pBt) );
+  if( !sqlite3PagerOkToChangeJournalMode(pPager) ) eNew = eOld;
+
+#ifndef SQLITE_OMIT_WAL
+  zFilename = sqlite3PagerFilename(pPager, 1);
+
+  /* Do not allow a transition to journal_mode=WAL for a database
+  ** in temporary storage or if the VFS does not support shared memory
+  */
+  if( eNew==PAGER_JOURNALMODE_WAL
+   && (sqlite3Strlen30(zFilename)==0           /* Temp file */
+       || !sqlite3PagerWalSupported(pPager))   /* No shared-memory support */
+  ){
+    eNew = eOld;
+  }
+
+  if( (eNew!=eOld)
+   && (eOld==PAGER_JOURNALMODE_WAL || eNew==PAGER_JOURNALMODE_WAL)
+  ){
+    if( !db->autoCommit || db->nVdbeRead>1 ){
+      rc = SQLITE_ERROR;
+      sqlite3VdbeError(p,
+          "cannot change %s wal mode from within a transaction",
+          (eNew==PAGER_JOURNALMODE_WAL ? "into" : "out of")
+      );
+      goto abort_due_to_error;
+    }else{
+
+      if( eOld==PAGER_JOURNALMODE_WAL ){
+        /* If leaving WAL mode, close the log file. If successful, the call
+        ** to PagerCloseWal() checkpoints and deletes the write-ahead-log
+        ** file. An EXCLUSIVE lock may still be held on the database file
+        ** after a successful return.
+        */
+        rc = sqlite3PagerCloseWal(pPager, db);
+        if( rc==SQLITE_OK ){
+          sqlite3PagerSetJournalMode(pPager, eNew);
+        }
+      }else if( eOld==PAGER_JOURNALMODE_MEMORY ){
+        /* Cannot transition directly from MEMORY to WAL.  Use mode OFF
+        ** as an intermediate */
+        sqlite3PagerSetJournalMode(pPager, PAGER_JOURNALMODE_OFF);
+      }
+
+      /* Open a transaction on the database file. Regardless of the journal
+      ** mode, this transaction always uses a rollback journal.
+      */
+      assert( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_WRITE );
+      if( rc==SQLITE_OK ){
+        rc = sqlite3BtreeSetVersion(pBt, (eNew==PAGER_JOURNALMODE_WAL ? 2 : 1));
+      }
+    }
+  }
+#endif /* ifndef SQLITE_OMIT_WAL */
+
+  if( rc ) eNew = eOld;
+  eNew = sqlite3PagerSetJournalMode(pPager, eNew);
+
+  pOut->flags = MEM_Str|MEM_Static|MEM_Term;
+  pOut->z = (char *)sqlite3JournalModename(eNew);
+  pOut->n = sqlite3Strlen30(pOut->z);
+  pOut->enc = SQLITE_UTF8;
+  sqlite3VdbeChangeEncoding(pOut, encoding);
+  if( rc ) goto abort_due_to_error;
+  break;
+};
+#endif /* SQLITE_OMIT_PRAGMA */
+
+#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
+/* Opcode: Vacuum P1 P2 * * *
+**
+** Vacuum the entire database P1.  P1 is 0 for "main", and 2 or more
+** for an attached database.  The "temp" database may not be vacuumed.
+**
+** If P2 is not zero, then it is a register holding a string which is
+** the file into which the result of vacuum should be written.  When
+** P2 is zero, the vacuum overwrites the original database.
+*/
+case OP_Vacuum: {
+  assert( p->readOnly==0 );
+  rc = sqlite3RunVacuum(&p->zErrMsg, db, pOp->p1,
+                        pOp->p2 ? &aMem[pOp->p2] : 0);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif
+
+#if !defined(SQLITE_OMIT_AUTOVACUUM)
+/* Opcode: IncrVacuum P1 P2 * * *
+**
+** Perform a single step of the incremental vacuum procedure on
+** the P1 database. If the vacuum has finished, jump to instruction
+** P2. Otherwise, fall through to the next instruction.
+*/
+case OP_IncrVacuum: {        /* jump */
+  Btree *pBt;
+
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p1) );
+  assert( p->readOnly==0 );
+  pBt = db->aDb[pOp->p1].pBt;
+  rc = sqlite3BtreeIncrVacuum(pBt);
+  VdbeBranchTaken(rc==SQLITE_DONE,2);
+  if( rc ){
+    if( rc!=SQLITE_DONE ) goto abort_due_to_error;
+    rc = SQLITE_OK;
+    goto jump_to_p2;
+  }
+  break;
+}
+#endif
+
+/* Opcode: Expire P1 P2 * * *
+**
+** Cause precompiled statements to expire.  When an expired statement
+** is executed using sqlite3_step() it will either automatically
+** reprepare itself (if it was originally created using sqlite3_prepare_v2())
+** or it will fail with SQLITE_SCHEMA.
+**
+** If P1 is 0, then all SQL statements become expired. If P1 is non-zero,
+** then only the currently executing statement is expired.
+**
+** If P2 is 0, then SQL statements are expired immediately.  If P2 is 1,
+** then running SQL statements are allowed to continue to run to completion.
+** The P2==1 case occurs when a CREATE INDEX or similar schema change happens
+** that might help the statement run faster but which does not affect the
+** correctness of operation.
+*/
+case OP_Expire: {
+  assert( pOp->p2==0 || pOp->p2==1 );
+  if( !pOp->p1 ){
+    sqlite3ExpirePreparedStatements(db, pOp->p2);
+  }else{
+    p->expired = pOp->p2+1;
+  }
+  break;
+}
+
+/* Opcode: CursorLock P1 * * * *
+**
+** Lock the btree to which cursor P1 is pointing so that the btree cannot be
+** written by an other cursor.
+*/
+case OP_CursorLock: {
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  sqlite3BtreeCursorPin(pC->uc.pCursor);
+  break;
+}
+
+/* Opcode: CursorUnlock P1 * * * *
+**
+** Unlock the btree to which cursor P1 is pointing so that it can be
+** written by other cursors.
+*/
+case OP_CursorUnlock: {
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  sqlite3BtreeCursorUnpin(pC->uc.pCursor);
+  break;
+}
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/* Opcode: TableLock P1 P2 P3 P4 *
+** Synopsis: iDb=P1 root=P2 write=P3
+**
+** Obtain a lock on a particular table. This instruction is only used when
+** the shared-cache feature is enabled.
+**
+** P1 is the index of the database in sqlite3.aDb[] of the database
+** on which the lock is acquired.  A readlock is obtained if P3==0 or
+** a write lock if P3==1.
+**
+** P2 contains the root-page of the table to lock.
+**
+** P4 contains a pointer to the name of the table being locked. This is only
+** used to generate an error message if the lock cannot be obtained.
+*/
+case OP_TableLock: {
+  u8 isWriteLock = (u8)pOp->p3;
+  if( isWriteLock || 0==(db->flags&SQLITE_ReadUncommit) ){
+    int p1 = pOp->p1;
+    assert( p1>=0 && p1<db->nDb );
+    assert( DbMaskTest(p->btreeMask, p1) );
+    assert( isWriteLock==0 || isWriteLock==1 );
+    rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
+    if( rc ){
+      if( (rc&0xFF)==SQLITE_LOCKED ){
+        const char *z = pOp->p4.z;
+        sqlite3VdbeError(p, "database table is locked: %s", z);
+      }
+      goto abort_due_to_error;
+    }
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VBegin * * * P4 *
+**
+** P4 may be a pointer to an sqlite3_vtab structure. If so, call the
+** xBegin method for that table.
+**
+** Also, whether or not P4 is set, check that this is not being called from
+** within a callback to a virtual table xSync() method. If it is, the error
+** code will be set to SQLITE_LOCKED.
+*/
+case OP_VBegin: {
+  VTable *pVTab;
+  pVTab = pOp->p4.pVtab;
+  rc = sqlite3VtabBegin(db, pVTab);
+  if( pVTab ) sqlite3VtabImportErrmsg(p, pVTab->pVtab);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VCreate P1 P2 * * *
+**
+** P2 is a register that holds the name of a virtual table in database
+** P1. Call the xCreate method for that table.
+*/
+case OP_VCreate: {
+  Mem sMem;          /* For storing the record being decoded */
+  const char *zTab;  /* Name of the virtual table */
+
+  memset(&sMem, 0, sizeof(sMem));
+  sMem.db = db;
+  /* Because P2 is always a static string, it is impossible for the
+  ** sqlite3VdbeMemCopy() to fail */
+  assert( (aMem[pOp->p2].flags & MEM_Str)!=0 );
+  assert( (aMem[pOp->p2].flags & MEM_Static)!=0 );
+  rc = sqlite3VdbeMemCopy(&sMem, &aMem[pOp->p2]);
+  assert( rc==SQLITE_OK );
+  zTab = (const char*)sqlite3_value_text(&sMem);
+  assert( zTab || db->mallocFailed );
+  if( zTab ){
+    rc = sqlite3VtabCallCreate(db, pOp->p1, zTab, &p->zErrMsg);
+  }
+  sqlite3VdbeMemRelease(&sMem);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VDestroy P1 * * P4 *
+**
+** P4 is the name of a virtual table in database P1.  Call the xDestroy method
+** of that table.
+*/
+case OP_VDestroy: {
+  db->nVDestroy++;
+  rc = sqlite3VtabCallDestroy(db, pOp->p1, pOp->p4.z);
+  db->nVDestroy--;
+  assert( p->errorAction==OE_Abort && p->usesStmtJournal );
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VOpen P1 * * P4 *
+**
+** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** P1 is a cursor number.  This opcode opens a cursor to the virtual
+** table and stores that cursor in P1.
+*/
+case OP_VOpen: {             /* ncycle */
+  VdbeCursor *pCur;
+  sqlite3_vtab_cursor *pVCur;
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+
+  assert( p->bIsReader );
+  pCur = 0;
+  pVCur = 0;
+  pVtab = pOp->p4.pVtab->pVtab;
+  if( pVtab==0 || NEVER(pVtab->pModule==0) ){
+    rc = SQLITE_LOCKED;
+    goto abort_due_to_error;
+  }
+  pModule = pVtab->pModule;
+  rc = pModule->xOpen(pVtab, &pVCur);
+  sqlite3VtabImportErrmsg(p, pVtab);
+  if( rc ) goto abort_due_to_error;
+
+  /* Initialize sqlite3_vtab_cursor base class */
+  pVCur->pVtab = pVtab;
+
+  /* Initialize vdbe cursor object */
+  pCur = allocateCursor(p, pOp->p1, 0, CURTYPE_VTAB);
+  if( pCur ){
+    pCur->uc.pVCur = pVCur;
+    pVtab->nRef++;
+  }else{
+    assert( db->mallocFailed );
+    pModule->xClose(pVCur);
+    goto no_mem;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VCheck P1 P2 P3 P4 *
+**
+** P4 is a pointer to a Table object that is a virtual table in schema P1
+** that supports the xIntegrity() method.  This opcode runs the xIntegrity()
+** method for that virtual table, using P3 as the integer argument.  If
+** an error is reported back, the table name is prepended to the error
+** message and that message is stored in P2.  If no errors are seen,
+** register P2 is set to NULL.
+*/
+case OP_VCheck: {             /* out2 */
+  Table *pTab;
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+  char *zErr = 0;
+
+  pOut = &aMem[pOp->p2];
+  sqlite3VdbeMemSetNull(pOut);  /* Innocent until proven guilty */
+  assert( pOp->p4type==P4_TABLEREF );
+  pTab = pOp->p4.pTab;
+  assert( pTab!=0 );
+  assert( pTab->nTabRef>0 );
+  assert( IsVirtual(pTab) );
+  if( pTab->u.vtab.p==0 ) break;
+  pVtab = pTab->u.vtab.p->pVtab;
+  assert( pVtab!=0 );
+  pModule = pVtab->pModule;
+  assert( pModule!=0 );
+  assert( pModule->iVersion>=4 );
+  assert( pModule->xIntegrity!=0 );
+  sqlite3VtabLock(pTab->u.vtab.p);
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  rc = pModule->xIntegrity(pVtab, db->aDb[pOp->p1].zDbSName, pTab->zName,
+                           pOp->p3, &zErr);
+  sqlite3VtabUnlock(pTab->u.vtab.p);
+  if( rc ){
+    sqlite3_free(zErr);
+    goto abort_due_to_error;
+  }
+  if( zErr ){
+    sqlite3VdbeMemSetStr(pOut, zErr, -1, SQLITE_UTF8, sqlite3_free);
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VInitIn P1 P2 P3 * *
+** Synopsis: r[P2]=ValueList(P1,P3)
+**
+** Set register P2 to be a pointer to a ValueList object for cursor P1
+** with cache register P3 and output register P3+1.  This ValueList object
+** can be used as the first argument to sqlite3_vtab_in_first() and
+** sqlite3_vtab_in_next() to extract all of the values stored in the P1
+** cursor.  Register P3 is used to hold the values returned by
+** sqlite3_vtab_in_first() and sqlite3_vtab_in_next().
+*/
+case OP_VInitIn: {        /* out2, ncycle */
+  VdbeCursor *pC;         /* The cursor containing the RHS values */
+  ValueList *pRhs;        /* New ValueList object to put in reg[P2] */
+
+  pC = p->apCsr[pOp->p1];
+  pRhs = sqlite3_malloc64( sizeof(*pRhs) );
+  if( pRhs==0 ) goto no_mem;
+  pRhs->pCsr = pC->uc.pCursor;
+  pRhs->pOut = &aMem[pOp->p3];
+  pOut = out2Prerelease(p, pOp);
+  pOut->flags = MEM_Null;
+  sqlite3VdbeMemSetPointer(pOut, pRhs, "ValueList", sqlite3VdbeValueListFree);
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VFilter P1 P2 P3 P4 *
+** Synopsis: iplan=r[P3] zplan='P4'
+**
+** P1 is a cursor opened using VOpen.  P2 is an address to jump to if
+** the filtered result set is empty.
+**
+** P4 is either NULL or a string that was generated by the xBestIndex
+** method of the module.  The interpretation of the P4 string is left
+** to the module implementation.
+**
+** This opcode invokes the xFilter method on the virtual table specified
+** by P1.  The integer query plan parameter to xFilter is stored in register
+** P3. Register P3+1 stores the argc parameter to be passed to the
+** xFilter method. Registers P3+2..P3+1+argc are the argc
+** additional parameters which are passed to
+** xFilter as argv. Register P3+2 becomes argv[0] when passed to xFilter.
+**
+** A jump is made to P2 if the result set after filtering would be empty.
+*/
+case OP_VFilter: {   /* jump, ncycle */
+  int nArg;
+  int iQuery;
+  const sqlite3_module *pModule;
+  Mem *pQuery;
+  Mem *pArgc;
+  sqlite3_vtab_cursor *pVCur;
+  sqlite3_vtab *pVtab;
+  VdbeCursor *pCur;
+  int res;
+  int i;
+  Mem **apArg;
+
+  pQuery = &aMem[pOp->p3];
+  pArgc = &pQuery[1];
+  pCur = p->apCsr[pOp->p1];
+  assert( memIsValid(pQuery) );
+  REGISTER_TRACE(pOp->p3, pQuery);
+  assert( pCur!=0 );
+  assert( pCur->eCurType==CURTYPE_VTAB );
+  pVCur = pCur->uc.pVCur;
+  pVtab = pVCur->pVtab;
+  pModule = pVtab->pModule;
+
+  /* Grab the index number and argc parameters */
+  assert( (pQuery->flags&MEM_Int)!=0 && pArgc->flags==MEM_Int );
+  nArg = (int)pArgc->u.i;
+  iQuery = (int)pQuery->u.i;
+
+  /* Invoke the xFilter method */
+  apArg = p->apArg;
+  for(i = 0; i<nArg; i++){
+    apArg[i] = &pArgc[i+1];
+  }
+  rc = pModule->xFilter(pVCur, iQuery, pOp->p4.z, nArg, apArg);
+  sqlite3VtabImportErrmsg(p, pVtab);
+  if( rc ) goto abort_due_to_error;
+  res = pModule->xEof(pVCur);
+  pCur->nullRow = 0;
+  VdbeBranchTaken(res!=0,2);
+  if( res ) goto jump_to_p2;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VColumn P1 P2 P3 * P5
+** Synopsis: r[P3]=vcolumn(P2)
+**
+** Store in register P3 the value of the P2-th column of
+** the current row of the virtual-table of cursor P1.
+**
+** If the VColumn opcode is being used to fetch the value of
+** an unchanging column during an UPDATE operation, then the P5
+** value is OPFLAG_NOCHNG.  This will cause the sqlite3_vtab_nochange()
+** function to return true inside the xColumn method of the virtual
+** table implementation.  The P5 column might also contain other
+** bits (OPFLAG_LENGTHARG or OPFLAG_TYPEOFARG) but those bits are
+** unused by OP_VColumn.
+*/
+case OP_VColumn: {           /* ncycle */
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+  Mem *pDest;
+  sqlite3_context sContext;
+  FuncDef nullFunc;
+
+  VdbeCursor *pCur = p->apCsr[pOp->p1];
+  assert( pCur!=0 );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  pDest = &aMem[pOp->p3];
+  memAboutToChange(p, pDest);
+  if( pCur->nullRow ){
+    sqlite3VdbeMemSetNull(pDest);
+    break;
+  }
+  assert( pCur->eCurType==CURTYPE_VTAB );
+  pVtab = pCur->uc.pVCur->pVtab;
+  pModule = pVtab->pModule;
+  assert( pModule->xColumn );
+  memset(&sContext, 0, sizeof(sContext));
+  sContext.pOut = pDest;
+  sContext.enc = encoding;
+  nullFunc.pUserData = 0;
+  nullFunc.funcFlags = SQLITE_RESULT_SUBTYPE;
+  sContext.pFunc = &nullFunc;
+  assert( pOp->p5==OPFLAG_NOCHNG || pOp->p5==0 );
+  if( pOp->p5 & OPFLAG_NOCHNG ){
+    sqlite3VdbeMemSetNull(pDest);
+    pDest->flags = MEM_Null|MEM_Zero;
+    pDest->u.nZero = 0;
+  }else{
+    MemSetTypeFlag(pDest, MEM_Null);
+  }
+  rc = pModule->xColumn(pCur->uc.pVCur, &sContext, pOp->p2);
+  sqlite3VtabImportErrmsg(p, pVtab);
+  if( sContext.isError>0 ){
+    sqlite3VdbeError(p, "%s", sqlite3_value_text(pDest));
+    rc = sContext.isError;
+  }
+  sqlite3VdbeChangeEncoding(pDest, encoding);
+  REGISTER_TRACE(pOp->p3, pDest);
+  UPDATE_MAX_BLOBSIZE(pDest);
+
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VNext P1 P2 * * *
+**
+** Advance virtual table P1 to the next row in its result set and
+** jump to instruction P2.  Or, if the virtual table has reached
+** the end of its result set, then fall through to the next instruction.
+*/
+case OP_VNext: {   /* jump, ncycle */
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+  int res;
+  VdbeCursor *pCur;
+
+  pCur = p->apCsr[pOp->p1];
+  assert( pCur!=0 );
+  assert( pCur->eCurType==CURTYPE_VTAB );
+  if( pCur->nullRow ){
+    break;
+  }
+  pVtab = pCur->uc.pVCur->pVtab;
+  pModule = pVtab->pModule;
+  assert( pModule->xNext );
+
+  /* Invoke the xNext() method of the module. There is no way for the
+  ** underlying implementation to return an error if one occurs during
+  ** xNext(). Instead, if an error occurs, true is returned (indicating that
+  ** data is available) and the error code returned when xColumn or
+  ** some other method is next invoked on the save virtual table cursor.
+  */
+  rc = pModule->xNext(pCur->uc.pVCur);
+  sqlite3VtabImportErrmsg(p, pVtab);
+  if( rc ) goto abort_due_to_error;
+  res = pModule->xEof(pCur->uc.pVCur);
+  VdbeBranchTaken(!res,2);
+  if( !res ){
+    /* If there is data, jump to P2 */
+    goto jump_to_p2_and_check_for_interrupt;
+  }
+  goto check_for_interrupt;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VRename P1 * * P4 *
+**
+** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** This opcode invokes the corresponding xRename method. The value
+** in register P1 is passed as the zName argument to the xRename method.
+*/
+case OP_VRename: {
+  sqlite3_vtab *pVtab;
+  Mem *pName;
+  int isLegacy;
+
+  isLegacy = (db->flags & SQLITE_LegacyAlter);
+  db->flags |= SQLITE_LegacyAlter;
+  pVtab = pOp->p4.pVtab->pVtab;
+  pName = &aMem[pOp->p1];
+  assert( pVtab->pModule->xRename );
+  assert( memIsValid(pName) );
+  assert( p->readOnly==0 );
+  REGISTER_TRACE(pOp->p1, pName);
+  assert( pName->flags & MEM_Str );
+  testcase( pName->enc==SQLITE_UTF8 );
+  testcase( pName->enc==SQLITE_UTF16BE );
+  testcase( pName->enc==SQLITE_UTF16LE );
+  rc = sqlite3VdbeChangeEncoding(pName, SQLITE_UTF8);
+  if( rc ) goto abort_due_to_error;
+  rc = pVtab->pModule->xRename(pVtab, pName->z);
+  if( isLegacy==0 ) db->flags &= ~(u64)SQLITE_LegacyAlter;
+  sqlite3VtabImportErrmsg(p, pVtab);
+  p->expired = 0;
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VUpdate P1 P2 P3 P4 P5
+** Synopsis: data=r[P3@P2]
+**
+** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** This opcode invokes the corresponding xUpdate method. P2 values
+** are contiguous memory cells starting at P3 to pass to the xUpdate
+** invocation. The value in register (P3+P2-1) corresponds to the
+** p2th element of the argv array passed to xUpdate.
+**
+** The xUpdate method will do a DELETE or an INSERT or both.
+** The argv[0] element (which corresponds to memory cell P3)
+** is the rowid of a row to delete.  If argv[0] is NULL then no
+** deletion occurs.  The argv[1] element is the rowid of the new
+** row.  This can be NULL to have the virtual table select the new
+** rowid for itself.  The subsequent elements in the array are
+** the values of columns in the new row.
+**
+** If P2==1 then no insert is performed.  argv[0] is the rowid of
+** a row to delete.
+**
+** P1 is a boolean flag. If it is set to true and the xUpdate call
+** is successful, then the value returned by sqlite3_last_insert_rowid()
+** is set to the value of the rowid for the row just inserted.
+**
+** P5 is the error actions (OE_Replace, OE_Fail, OE_Ignore, etc) to
+** apply in the case of a constraint failure on an insert or update.
+*/
+case OP_VUpdate: {
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+  int nArg;
+  int i;
+  sqlite_int64 rowid = 0;
+  Mem **apArg;
+  Mem *pX;
+
+  assert( pOp->p2==1        || pOp->p5==OE_Fail   || pOp->p5==OE_Rollback
+       || pOp->p5==OE_Abort || pOp->p5==OE_Ignore || pOp->p5==OE_Replace
+  );
+  assert( p->readOnly==0 );
+  if( db->mallocFailed ) goto no_mem;
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  pVtab = pOp->p4.pVtab->pVtab;
+  if( pVtab==0 || NEVER(pVtab->pModule==0) ){
+    rc = SQLITE_LOCKED;
+    goto abort_due_to_error;
+  }
+  pModule = pVtab->pModule;
+  nArg = pOp->p2;
+  assert( pOp->p4type==P4_VTAB );
+  if( ALWAYS(pModule->xUpdate) ){
+    u8 vtabOnConflict = db->vtabOnConflict;
+    apArg = p->apArg;
+    pX = &aMem[pOp->p3];
+    for(i=0; i<nArg; i++){
+      assert( memIsValid(pX) );
+      memAboutToChange(p, pX);
+      apArg[i] = pX;
+      pX++;
+    }
+    db->vtabOnConflict = pOp->p5;
+    rc = pModule->xUpdate(pVtab, nArg, apArg, &rowid);
+    db->vtabOnConflict = vtabOnConflict;
+    sqlite3VtabImportErrmsg(p, pVtab);
+    if( rc==SQLITE_OK && pOp->p1 ){
+      assert( nArg>1 && apArg[0] && (apArg[0]->flags&MEM_Null) );
+      db->lastRowid = rowid;
+    }
+    if( (rc&0xff)==SQLITE_CONSTRAINT && pOp->p4.pVtab->bConstraint ){
+      if( pOp->p5==OE_Ignore ){
+        rc = SQLITE_OK;
+      }else{
+        p->errorAction = ((pOp->p5==OE_Replace) ? OE_Abort : pOp->p5);
+      }
+    }else{
+      p->nChange++;
+    }
+    if( rc ) goto abort_due_to_error;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef  SQLITE_OMIT_PAGER_PRAGMAS
+/* Opcode: Pagecount P1 P2 * * *
+**
+** Write the current number of pages in database P1 to memory cell P2.
+*/
+case OP_Pagecount: {            /* out2 */
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = sqlite3BtreeLastPage(db->aDb[pOp->p1].pBt);
+  break;
+}
+#endif
+
+
+#ifndef  SQLITE_OMIT_PAGER_PRAGMAS
+/* Opcode: MaxPgcnt P1 P2 P3 * *
+**
+** Try to set the maximum page count for database P1 to the value in P3.
+** Do not let the maximum page count fall below the current page count and
+** do not change the maximum page count value if P3==0.
+**
+** Store the maximum page count after the change in register P2.
+*/
+case OP_MaxPgcnt: {            /* out2 */
+  unsigned int newMax;
+  Btree *pBt;
+
+  pOut = out2Prerelease(p, pOp);
+  pBt = db->aDb[pOp->p1].pBt;
+  newMax = 0;
+  if( pOp->p3 ){
+    newMax = sqlite3BtreeLastPage(pBt);
+    if( newMax < (unsigned)pOp->p3 ) newMax = (unsigned)pOp->p3;
+  }
+  pOut->u.i = sqlite3BtreeMaxPageCount(pBt, newMax);
+  break;
+}
+#endif
+
+/* Opcode: Function P1 P2 P3 P4 *
+** Synopsis: r[P3]=func(r[P2@NP])
+**
+** Invoke a user function (P4 is a pointer to an sqlite3_context object that
+** contains a pointer to the function to be run) with arguments taken
+** from register P2 and successors.  The number of arguments is in
+** the sqlite3_context object that P4 points to.
+** The result of the function is stored
+** in register P3.  Register P3 must not be one of the function inputs.
+**
+** P1 is a 32-bit bitmask indicating whether or not each argument to the
+** function was determined to be constant at compile time. If the first
+** argument was constant then bit 0 of P1 is set. This is used to determine
+** whether meta data associated with a user function argument using the
+** sqlite3_set_auxdata() API may be safely retained until the next
+** invocation of this opcode.
+**
+** See also: AggStep, AggFinal, PureFunc
+*/
+/* Opcode: PureFunc P1 P2 P3 P4 *
+** Synopsis: r[P3]=func(r[P2@NP])
+**
+** Invoke a user function (P4 is a pointer to an sqlite3_context object that
+** contains a pointer to the function to be run) with arguments taken
+** from register P2 and successors.  The number of arguments is in
+** the sqlite3_context object that P4 points to.
+** The result of the function is stored
+** in register P3.  Register P3 must not be one of the function inputs.
+**
+** P1 is a 32-bit bitmask indicating whether or not each argument to the
+** function was determined to be constant at compile time. If the first
+** argument was constant then bit 0 of P1 is set. This is used to determine
+** whether meta data associated with a user function argument using the
+** sqlite3_set_auxdata() API may be safely retained until the next
+** invocation of this opcode.
+**
+** This opcode works exactly like OP_Function.  The only difference is in
+** its name.  This opcode is used in places where the function must be
+** purely non-deterministic.  Some built-in date/time functions can be
+** either deterministic of non-deterministic, depending on their arguments.
+** When those function are used in a non-deterministic way, they will check
+** to see if they were called using OP_PureFunc instead of OP_Function, and
+** if they were, they throw an error.
+**
+** See also: AggStep, AggFinal, Function
+*/
+case OP_PureFunc:              /* group */
+case OP_Function: {            /* group */
+  int i;
+  sqlite3_context *pCtx;
+
+  assert( pOp->p4type==P4_FUNCCTX );
+  pCtx = pOp->p4.pCtx;
+
+  /* If this function is inside of a trigger, the register array in aMem[]
+  ** might change from one evaluation to the next.  The next block of code
+  ** checks to see if the register array has changed, and if so it
+  ** reinitializes the relevant parts of the sqlite3_context object */
+  pOut = &aMem[pOp->p3];
+  if( pCtx->pOut != pOut ){
+    pCtx->pVdbe = p;
+    pCtx->pOut = pOut;
+    pCtx->enc = encoding;
+    for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
+  }
+  assert( pCtx->pVdbe==p );
+
+  memAboutToChange(p, pOut);
+#ifdef SQLITE_DEBUG
+  for(i=0; i<pCtx->argc; i++){
+    assert( memIsValid(pCtx->argv[i]) );
+    REGISTER_TRACE(pOp->p2+i, pCtx->argv[i]);
+  }
+#endif
+  MemSetTypeFlag(pOut, MEM_Null);
+  assert( pCtx->isError==0 );
+  (*pCtx->pFunc->xSFunc)(pCtx, pCtx->argc, pCtx->argv);/* IMP: R-24505-23230 */
+
+  /* If the function returned an error, throw an exception */
+  if( pCtx->isError ){
+    if( pCtx->isError>0 ){
+      sqlite3VdbeError(p, "%s", sqlite3_value_text(pOut));
+      rc = pCtx->isError;
+    }
+    sqlite3VdbeDeleteAuxData(db, &p->pAuxData, pCtx->iOp, pOp->p1);
+    pCtx->isError = 0;
+    if( rc ) goto abort_due_to_error;
+  }
+
+  assert( (pOut->flags&MEM_Str)==0
+       || pOut->enc==encoding
+       || db->mallocFailed );
+  assert( !sqlite3VdbeMemTooBig(pOut) );
+
+  REGISTER_TRACE(pOp->p3, pOut);
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: ClrSubtype P1 * * * *
+** Synopsis:  r[P1].subtype = 0
+**
+** Clear the subtype from register P1.
+*/
+case OP_ClrSubtype: {   /* in1 */
+  pIn1 = &aMem[pOp->p1];
+  pIn1->flags &= ~MEM_Subtype;
+  break;
+}
+
+/* Opcode: GetSubtype P1 P2 * * *
+** Synopsis:  r[P2] = r[P1].subtype
+**
+** Extract the subtype value from register P1 and write that subtype
+** into register P2.  If P1 has no subtype, then P1 gets a NULL.
+*/
+case OP_GetSubtype: {   /* in1 out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  if( pIn1->flags & MEM_Subtype ){
+    sqlite3VdbeMemSetInt64(pOut, pIn1->eSubtype);
+  }else{
+    sqlite3VdbeMemSetNull(pOut);
+  }
+  break;
+}
+
+/* Opcode: SetSubtype P1 P2 * * *
+** Synopsis:  r[P2].subtype = r[P1]
+**
+** Set the subtype value of register P2 to the integer from register P1.
+** If P1 is NULL, clear the subtype from p2.
+*/
+case OP_SetSubtype: {   /* in1 out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  if( pIn1->flags & MEM_Null ){
+    pOut->flags &= ~MEM_Subtype;
+  }else{
+    assert( pIn1->flags & MEM_Int );
+    pOut->flags |= MEM_Subtype;
+    pOut->eSubtype = (u8)(pIn1->u.i & 0xff);
+  }
+  break;
+}
+
+/* Opcode: FilterAdd P1 * P3 P4 *
+** Synopsis: filter(P1) += key(P3@P4)
+**
+** Compute a hash on the P4 registers starting with r[P3] and
+** add that hash to the bloom filter contained in r[P1].
+*/
+case OP_FilterAdd: {
+  u64 h;
+
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags & MEM_Blob );
+  assert( pIn1->n>0 );
+  h = filterHash(aMem, pOp);
+#ifdef SQLITE_DEBUG
+  if( db->flags&SQLITE_VdbeTrace ){
+    int ii;
+    for(ii=pOp->p3; ii<pOp->p3+pOp->p4.i; ii++){
+      registerTrace(ii, &aMem[ii]);
+    }
+    printf("hash: %llu modulo %d -> %u\n", h, pIn1->n, (int)(h%pIn1->n));
+  }
+#endif
+  h %= (pIn1->n*8);
+  pIn1->z[h/8] |= 1<<(h&7);
+  break;
+}
+
+/* Opcode: Filter P1 P2 P3 P4 *
+** Synopsis: if key(P3@P4) not in filter(P1) goto P2
+**
+** Compute a hash on the key contained in the P4 registers starting
+** with r[P3].  Check to see if that hash is found in the
+** bloom filter hosted by register P1.  If it is not present then
+** maybe jump to P2.  Otherwise fall through.
+**
+** False negatives are harmless.  It is always safe to fall through,
+** even if the value is in the bloom filter.  A false negative causes
+** more CPU cycles to be used, but it should still yield the correct
+** answer.  However, an incorrect answer may well arise from a
+** false positive - if the jump is taken when it should fall through.
+*/
+case OP_Filter: {          /* jump */
+  u64 h;
+
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  pIn1 = &aMem[pOp->p1];
+  assert( (pIn1->flags & MEM_Blob)!=0 );
+  assert( pIn1->n >= 1 );
+  h = filterHash(aMem, pOp);
+#ifdef SQLITE_DEBUG
+  if( db->flags&SQLITE_VdbeTrace ){
+    int ii;
+    for(ii=pOp->p3; ii<pOp->p3+pOp->p4.i; ii++){
+      registerTrace(ii, &aMem[ii]);
+    }
+    printf("hash: %llu modulo %d -> %u\n", h, pIn1->n, (int)(h%pIn1->n));
+  }
+#endif
+  h %= (pIn1->n*8);
+  if( (pIn1->z[h/8] & (1<<(h&7)))==0 ){
+    VdbeBranchTaken(1, 2);
+    p->aCounter[SQLITE_STMTSTATUS_FILTER_HIT]++;
+    goto jump_to_p2;
+  }else{
+    p->aCounter[SQLITE_STMTSTATUS_FILTER_MISS]++;
+    VdbeBranchTaken(0, 2);
+  }
+  break;
+}
+
+/* Opcode: Trace P1 P2 * P4 *
+**
+** Write P4 on the statement trace output if statement tracing is
+** enabled.
+**
+** Operand P1 must be 0x7fffffff and P2 must positive.
+*/
+/* Opcode: Init P1 P2 P3 P4 *
+** Synopsis: Start at P2
+**
+** Programs contain a single instance of this opcode as the very first
+** opcode.
+**
+** If tracing is enabled (by the sqlite3_trace()) interface, then
+** the UTF-8 string contained in P4 is emitted on the trace callback.
+** Or if P4 is blank, use the string returned by sqlite3_sql().
+**
+** If P2 is not zero, jump to instruction P2.
+**
+** Increment the value of P1 so that OP_Once opcodes will jump the
+** first time they are evaluated for this run.
+**
+** If P3 is not zero, then it is an address to jump to if an SQLITE_CORRUPT
+** error is encountered.
+*/
+case OP_Trace:
+case OP_Init: {          /* jump0 */
+  int i;
+#ifndef SQLITE_OMIT_TRACE
+  char *zTrace;
+#endif
+
+  /* If the P4 argument is not NULL, then it must be an SQL comment string.
+  ** The "--" string is broken up to prevent false-positives with srcck1.c.
+  **
+  ** This assert() provides evidence for:
+  ** EVIDENCE-OF: R-50676-09860 The callback can compute the same text that
+  ** would have been returned by the legacy sqlite3_trace() interface by
+  ** using the X argument when X begins with "--" and invoking
+  ** sqlite3_expanded_sql(P) otherwise.
+  */
+  assert( pOp->p4.z==0 || strncmp(pOp->p4.z, "-" "- ", 3)==0 );
+
+  /* OP_Init is always instruction 0 */
+  assert( pOp==p->aOp || pOp->opcode==OP_Trace );
+
+#ifndef SQLITE_OMIT_TRACE
+  if( (db->mTrace & (SQLITE_TRACE_STMT|SQLITE_TRACE_LEGACY))!=0
+   && p->minWriteFileFormat!=254  /* tag-20220401a */
+   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
+  ){
+#ifndef SQLITE_OMIT_DEPRECATED
+    if( db->mTrace & SQLITE_TRACE_LEGACY ){
+      char *z = sqlite3VdbeExpandSql(p, zTrace);
+      db->trace.xLegacy(db->pTraceArg, z);
+      sqlite3_free(z);
+    }else
+#endif
+    if( db->nVdbeExec>1 ){
+      char *z = sqlite3MPrintf(db, "-- %s", zTrace);
+      (void)db->trace.xV2(SQLITE_TRACE_STMT, db->pTraceArg, p, z);
+      sqlite3DbFree(db, z);
+    }else{
+      (void)db->trace.xV2(SQLITE_TRACE_STMT, db->pTraceArg, p, zTrace);
+    }
+  }
+#ifdef SQLITE_USE_FCNTL_TRACE
+  zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql);
+  if( zTrace ){
+    int j;
+    for(j=0; j<db->nDb; j++){
+      if( DbMaskTest(p->btreeMask, j)==0 ) continue;
+      sqlite3_file_control(db, db->aDb[j].zDbSName, SQLITE_FCNTL_TRACE, zTrace);
+    }
+  }
+#endif /* SQLITE_USE_FCNTL_TRACE */
+#ifdef SQLITE_DEBUG
+  if( (db->flags & SQLITE_SqlTrace)!=0
+   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
+  ){
+    sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
+  }
+#endif /* SQLITE_DEBUG */
+#endif /* SQLITE_OMIT_TRACE */
+  assert( pOp->p2>0 );
+  if( pOp->p1>=sqlite3GlobalConfig.iOnceResetThreshold ){
+    if( pOp->opcode==OP_Trace ) break;
+    for(i=1; i<p->nOp; i++){
+      if( p->aOp[i].opcode==OP_Once ) p->aOp[i].p1 = 0;
+    }
+    pOp->p1 = 0;
+  }
+  pOp->p1++;
+  p->aCounter[SQLITE_STMTSTATUS_RUN]++;
+  goto jump_to_p2;
+}
+
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/* Opcode: CursorHint P1 * * P4 *
+**
+** Provide a hint to cursor P1 that it only needs to return rows that
+** satisfy the Expr in P4.  TK_REGISTER terms in the P4 expression refer
+** to values currently held in registers.  TK_COLUMN terms in the P4
+** expression refer to columns in the b-tree to which cursor P1 is pointing.
+*/
+case OP_CursorHint: {
+  VdbeCursor *pC;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p4type==P4_EXPR );
+  pC = p->apCsr[pOp->p1];
+  if( pC ){
+    assert( pC->eCurType==CURTYPE_BTREE );
+    sqlite3BtreeCursorHint(pC->uc.pCursor, BTREE_HINT_RANGE,
+                           pOp->p4.pExpr, aMem);
+  }
+  break;
+}
+#endif /* SQLITE_ENABLE_CURSOR_HINTS */
+
+#ifdef SQLITE_DEBUG
+/* Opcode:  Abortable   * * * * *
+**
+** Verify that an Abort can happen.  Assert if an Abort at this point
+** might cause database corruption.  This opcode only appears in debugging
+** builds.
+**
+** An Abort is safe if either there have been no writes, or if there is
+** an active statement journal.
+*/
+case OP_Abortable: {
+  sqlite3VdbeAssertAbortable(p);
+  break;
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/* Opcode:  ReleaseReg   P1 P2 P3 * P5
+** Synopsis: release r[P1@P2] mask P3
+**
+** Release registers from service.  Any content that was in the
+** the registers is unreliable after this opcode completes.
+**
+** The registers released will be the P2 registers starting at P1,
+** except if bit ii of P3 set, then do not release register P1+ii.
+** In other words, P3 is a mask of registers to preserve.
+**
+** Releasing a register clears the Mem.pScopyFrom pointer.  That means
+** that if the content of the released register was set using OP_SCopy,
+** a change to the value of the source register for the OP_SCopy will no longer
+** generate an assertion fault in sqlite3VdbeMemAboutToChange().
+**
+** If P5 is set, then all released registers have their type set
+** to MEM_Undefined so that any subsequent attempt to read the released
+** register (before it is reinitialized) will generate an assertion fault.
+**
+** P5 ought to be set on every call to this opcode.
+** However, there are places in the code generator will release registers
+** before their are used, under the (valid) assumption that the registers
+** will not be reallocated for some other purpose before they are used and
+** hence are safe to release.
+**
+** This opcode is only available in testing and debugging builds.  It is
+** not generated for release builds.  The purpose of this opcode is to help
+** validate the generated bytecode.  This opcode does not actually contribute
+** to computing an answer.
+*/
+case OP_ReleaseReg: {
+  Mem *pMem;
+  int i;
+  u32 constMask;
+  assert( pOp->p1>0 );
+  assert( pOp->p1+pOp->p2<=(p->nMem+1 - p->nCursor)+1 );
+  pMem = &aMem[pOp->p1];
+  constMask = pOp->p3;
+  for(i=0; i<pOp->p2; i++, pMem++){
+    if( i>=32 || (constMask & MASKBIT32(i))==0 ){
+      pMem->pScopyFrom = 0;
+      if( i<32 && pOp->p5 ) MemSetTypeFlag(pMem, MEM_Undefined);
+    }
+  }
+  break;
+}
+#endif
+
+/* Opcode: Noop * * * * *
+**
+** Do nothing.  Continue downward to the next opcode.
+*/
+/* Opcode: Explain P1 P2 P3 P4 *
+**
+** This is the same as OP_Noop during normal query execution.  The
+** purpose of this opcode is to hold information about the query
+** plan for the purpose of EXPLAIN QUERY PLAN output.
+**
+** The P4 value is human-readable text that describes the query plan
+** element.  Something like "SCAN t1" or "SEARCH t2 USING INDEX t2x1".
+**
+** The P1 value is the ID of the current element and P2 is the parent
+** element for the case of nested query plan elements.  If P2 is zero
+** then this element is a top-level element.
+**
+** For loop elements, P3 is the estimated code of each invocation of this
+** element.
+**
+** As with all opcodes, the meanings of the parameters for OP_Explain
+** are subject to change from one release to the next.  Applications
+** should not attempt to interpret or use any of the information
+** contained in the OP_Explain opcode.  The information provided by this
+** opcode is intended for testing and debugging use only.
+*/
+default: {          /* This is really OP_Noop, OP_Explain */
+  assert( pOp->opcode==OP_Noop || pOp->opcode==OP_Explain );
+
+  break;
+}
+
+/*****************************************************************************
+** The cases of the switch statement above this line should all be indented
+** by 6 spaces.  But the left-most 6 spaces have been removed to improve the
+** readability.  From this point on down, the normal indentation rules are
+** restored.
+*****************************************************************************/
+    }
+
+#if defined(VDBE_PROFILE)
+    *pnCycle += sqlite3NProfileCnt ? sqlite3NProfileCnt : sqlite3Hwtime();
+    pnCycle = 0;
+#elif defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+    if( pnCycle ){
+      *pnCycle += sqlite3Hwtime();
+      pnCycle = 0;
+    }
+#endif
+
+    /* The following code adds nothing to the actual functionality
+    ** of the program.  It is only here for testing and debugging.
+    ** On the other hand, it does burn CPU cycles every time through
+    ** the evaluator loop.  So we can leave it out when NDEBUG is defined.
+    */
+#ifndef NDEBUG
+    assert( pOp>=&aOp[-1] && pOp<&aOp[p->nOp-1] );
+
+#ifdef SQLITE_DEBUG
+    if( db->flags & SQLITE_VdbeTrace ){
+      u8 opProperty = sqlite3OpcodeProperty[pOrigOp->opcode];
+      if( rc!=0 ) printf("rc=%d\n",rc);
+      if( opProperty & (OPFLG_OUT2) ){
+        registerTrace(pOrigOp->p2, &aMem[pOrigOp->p2]);
+      }
+      if( opProperty & OPFLG_OUT3 ){
+        registerTrace(pOrigOp->p3, &aMem[pOrigOp->p3]);
+      }
+      if( opProperty==0xff ){
+        /* Never happens.  This code exists to avoid a harmless linkage
+        ** warning about sqlite3VdbeRegisterDump() being defined but not
+        ** used. */
+        sqlite3VdbeRegisterDump(p);
+      }
+    }
+#endif  /* SQLITE_DEBUG */
+#endif  /* NDEBUG */
+  }  /* The end of the for(;;) loop the loops through opcodes */
+
+  /* If we reach this point, it means that execution is finished with
+  ** an error of some kind.
+  */
+abort_due_to_error:
+  if( db->mallocFailed ){
+    rc = SQLITE_NOMEM_BKPT;
+  }else if( rc==SQLITE_IOERR_CORRUPTFS ){
+    rc = SQLITE_CORRUPT_BKPT;
+  }
+  assert( rc );
+#ifdef SQLITE_DEBUG
+  if( db->flags & SQLITE_VdbeTrace ){
+    const char *zTrace = p->zSql;
+    if( zTrace==0 ){
+      if( aOp[0].opcode==OP_Trace ){
+        zTrace = aOp[0].p4.z;
+      }
+      if( zTrace==0 ) zTrace = "???";
+    }
+    printf("ABORT-due-to-error (rc=%d): %s\n", rc, zTrace);
+  }
+#endif
+  if( p->zErrMsg==0 && rc!=SQLITE_IOERR_NOMEM ){
+    sqlite3VdbeError(p, "%s", sqlite3ErrStr(rc));
+  }
+  p->rc = rc;
+  sqlite3SystemError(db, rc);
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  sqlite3_log(rc, "statement aborts at %d: [%s] %s",
+                   (int)(pOp - aOp), p->zSql, p->zErrMsg);
+  if( p->eVdbeState==VDBE_RUN_STATE ) sqlite3VdbeHalt(p);
+  if( rc==SQLITE_IOERR_NOMEM ) sqlite3OomFault(db);
+  if( rc==SQLITE_CORRUPT && db->autoCommit==0 ){
+    db->flags |= SQLITE_CorruptRdOnly;
+  }
+  rc = SQLITE_ERROR;
+  if( resetSchemaOnFault>0 ){
+    sqlite3ResetOneSchema(db, resetSchemaOnFault-1);
+  }
+
+  /* This is the only way out of this procedure.  We have to
+  ** release the mutexes on btrees that were acquired at the
+  ** top. */
+vdbe_return:
+#if defined(VDBE_PROFILE)
+  if( pnCycle ){
+    *pnCycle += sqlite3NProfileCnt ? sqlite3NProfileCnt : sqlite3Hwtime();
+    pnCycle = 0;
+  }
+#elif defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+  if( pnCycle ){
+    *pnCycle += sqlite3Hwtime();
+    pnCycle = 0;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  while( nVmStep>=nProgressLimit && db->xProgress!=0 ){
+    nProgressLimit += db->nProgressOps;
+    if( db->xProgress(db->pProgressArg) ){
+      nProgressLimit = LARGEST_UINT64;
+      rc = SQLITE_INTERRUPT;
+      goto abort_due_to_error;
+    }
+  }
+#endif
+  p->aCounter[SQLITE_STMTSTATUS_VM_STEP] += (int)nVmStep;
+  if( DbMaskNonZero(p->lockMask) ){
+    sqlite3VdbeLeave(p);
+  }
+  assert( rc!=SQLITE_OK || nExtraDelete==0
+       || sqlite3_strlike("DELETE%",p->zSql,0)!=0
+  );
+  return rc;
+
+  /* Jump to here if a string or blob larger than SQLITE_MAX_LENGTH
+  ** is encountered.
+  */
+too_big:
+  sqlite3VdbeError(p, "string or blob too big");
+  rc = SQLITE_TOOBIG;
+  goto abort_due_to_error;
+
+  /* Jump to here if a malloc() fails.
+  */
+no_mem:
+  sqlite3OomFault(db);
+  sqlite3VdbeError(p, "out of memory");
+  rc = SQLITE_NOMEM_BKPT;
+  goto abort_due_to_error;
+
+  /* Jump to here if the sqlite3_interrupt() API sets the interrupt
+  ** flag.
+  */
+abort_due_to_interrupt:
+  assert( AtomicLoad(&db->u1.isInterrupted) );
+  rc = SQLITE_INTERRUPT;
+  goto abort_due_to_error;
+}
+
+
+/************** End of vdbe.c ************************************************/
+/************** Begin file vdbeblob.c ****************************************/
+/*
+** 2007 May 1
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code used to implement incremental BLOB I/O.
+*/
+
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+#ifndef SQLITE_OMIT_INCRBLOB
+
+/*
+** Valid sqlite3_blob* handles point to Incrblob structures.
+*/
+typedef struct Incrblob Incrblob;
+struct Incrblob {
+  int nByte;              /* Size of open blob, in bytes */
+  int iOffset;            /* Byte offset of blob in cursor data */
+  u16 iCol;               /* Table column this handle is open on */
+  BtCursor *pCsr;         /* Cursor pointing at blob row */
+  sqlite3_stmt *pStmt;    /* Statement holding cursor open */
+  sqlite3 *db;            /* The associated database */
+  char *zDb;              /* Database name */
+  Table *pTab;            /* Table object */
+};
+
+
+/*
+** This function is used by both blob_open() and blob_reopen(). It seeks
+** the b-tree cursor associated with blob handle p to point to row iRow.
+** If successful, SQLITE_OK is returned and subsequent calls to
+** sqlite3_blob_read() or sqlite3_blob_write() access the specified row.
+**
+** If an error occurs, or if the specified row does not exist or does not
+** contain a value of type TEXT or BLOB in the column nominated when the
+** blob handle was opened, then an error code is returned and *pzErr may
+** be set to point to a buffer containing an error message. It is the
+** responsibility of the caller to free the error message buffer using
+** sqlite3DbFree().
+**
+** If an error does occur, then the b-tree cursor is closed. All subsequent
+** calls to sqlite3_blob_read(), blob_write() or blob_reopen() will
+** immediately return SQLITE_ABORT.
+*/
+static int blobSeekToRow(Incrblob *p, sqlite3_int64 iRow, char **pzErr){
+  int rc;                         /* Error code */
+  char *zErr = 0;                 /* Error message */
+  Vdbe *v = (Vdbe *)p->pStmt;
+
+  /* Set the value of register r[1] in the SQL statement to integer iRow.
+  ** This is done directly as a performance optimization
+  */
+  sqlite3VdbeMemSetInt64(&v->aMem[1], iRow);
+
+  /* If the statement has been run before (and is paused at the OP_ResultRow)
+  ** then back it up to the point where it does the OP_NotExists.  This could
+  ** have been down with an extra OP_Goto, but simply setting the program
+  ** counter is faster. */
+  if( v->pc>4 ){
+    v->pc = 4;
+    assert( v->aOp[v->pc].opcode==OP_NotExists );
+    rc = sqlite3VdbeExec(v);
+  }else{
+    rc = sqlite3_step(p->pStmt);
+  }
+  if( rc==SQLITE_ROW ){
+    VdbeCursor *pC = v->apCsr[0];
+    u32 type;
+    assert( pC!=0 );
+    assert( pC->eCurType==CURTYPE_BTREE );
+    type = pC->nHdrParsed>p->iCol ? pC->aType[p->iCol] : 0;
+    testcase( pC->nHdrParsed==p->iCol );
+    testcase( pC->nHdrParsed==p->iCol+1 );
+    if( type<12 ){
+      zErr = sqlite3MPrintf(p->db, "cannot open value of type %s",
+          type==0?"null": type==7?"real": "integer"
+      );
+      rc = SQLITE_ERROR;
+      sqlite3_finalize(p->pStmt);
+      p->pStmt = 0;
+    }else{
+      p->iOffset = pC->aType[p->iCol + pC->nField];
+      p->nByte = sqlite3VdbeSerialTypeLen(type);
+      p->pCsr =  pC->uc.pCursor;
+      sqlite3BtreeIncrblobCursor(p->pCsr);
+    }
+  }
+
+  if( rc==SQLITE_ROW ){
+    rc = SQLITE_OK;
+  }else if( p->pStmt ){
+    rc = sqlite3_finalize(p->pStmt);
+    p->pStmt = 0;
+    if( rc==SQLITE_OK ){
+      zErr = sqlite3MPrintf(p->db, "no such rowid: %lld", iRow);
+      rc = SQLITE_ERROR;
+    }else{
+      zErr = sqlite3MPrintf(p->db, "%s", sqlite3_errmsg(p->db));
+    }
+  }
+
+  assert( rc!=SQLITE_OK || zErr==0 );
+  assert( rc!=SQLITE_ROW && rc!=SQLITE_DONE );
+
+  *pzErr = zErr;
+  return rc;
+}
+
+/*
+** Open a blob handle.
+*/
+SQLITE_API int sqlite3_blob_open(
+  sqlite3* db,            /* The database connection */
+  const char *zDb,        /* The attached database containing the blob */
+  const char *zTable,     /* The table containing the blob */
+  const char *zColumn,    /* The column containing the blob */
+  sqlite_int64 iRow,      /* The row containing the glob */
+  int wrFlag,             /* True -> read/write access, false -> read-only */
+  sqlite3_blob **ppBlob   /* Handle for accessing the blob returned here */
+){
+  int nAttempt = 0;
+  int iCol;               /* Index of zColumn in row-record */
+  int rc = SQLITE_OK;
+  char *zErr = 0;
+  Table *pTab;
+  Incrblob *pBlob = 0;
+  Parse sParse;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppBlob==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  *ppBlob = 0;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zTable==0 || zColumn==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  wrFlag = !!wrFlag;                /* wrFlag = (wrFlag ? 1 : 0); */
+
+  sqlite3_mutex_enter(db->mutex);
+
+  pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
+  while(1){
+    sqlite3ParseObjectInit(&sParse,db);
+    if( !pBlob ) goto blob_open_out;
+    sqlite3DbFree(db, zErr);
+    zErr = 0;
+
+    sqlite3BtreeEnterAll(db);
+    pTab = sqlite3LocateTable(&sParse, 0, zTable, zDb);
+    if( pTab && IsVirtual(pTab) ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open virtual table: %s", zTable);
+    }
+    if( pTab && !HasRowid(pTab) ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open table without rowid: %s", zTable);
+    }
+    if( pTab && (pTab->tabFlags&TF_HasGenerated)!=0 ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open table with generated columns: %s",
+                      zTable);
+    }
+#ifndef SQLITE_OMIT_VIEW
+    if( pTab && IsView(pTab) ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open view: %s", zTable);
+    }
+#endif
+    if( !pTab ){
+      if( sParse.zErrMsg ){
+        sqlite3DbFree(db, zErr);
+        zErr = sParse.zErrMsg;
+        sParse.zErrMsg = 0;
+      }
+      rc = SQLITE_ERROR;
+      sqlite3BtreeLeaveAll(db);
+      goto blob_open_out;
+    }
+    pBlob->pTab = pTab;
+    pBlob->zDb = db->aDb[sqlite3SchemaToIndex(db, pTab->pSchema)].zDbSName;
+
+    /* Now search pTab for the exact column. */
+    for(iCol=0; iCol<pTab->nCol; iCol++) {
+      if( sqlite3StrICmp(pTab->aCol[iCol].zCnName, zColumn)==0 ){
+        break;
+      }
+    }
+    if( iCol==pTab->nCol ){
+      sqlite3DbFree(db, zErr);
+      zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
+      rc = SQLITE_ERROR;
+      sqlite3BtreeLeaveAll(db);
+      goto blob_open_out;
+    }
+
+    /* If the value is being opened for writing, check that the
+    ** column is not indexed, and that it is not part of a foreign key.
+    */
+    if( wrFlag ){
+      const char *zFault = 0;
+      Index *pIdx;
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+      if( db->flags&SQLITE_ForeignKeys ){
+        /* Check that the column is not part of an FK child key definition. It
+        ** is not necessary to check if it is part of a parent key, as parent
+        ** key columns must be indexed. The check below will pick up this
+        ** case.  */
+        FKey *pFKey;
+        assert( IsOrdinaryTable(pTab) );
+        for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+          int j;
+          for(j=0; j<pFKey->nCol; j++){
+            if( pFKey->aCol[j].iFrom==iCol ){
+              zFault = "foreign key";
+            }
+          }
+        }
+      }
+#endif
+      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+        int j;
+        for(j=0; j<pIdx->nKeyCol; j++){
+          /* FIXME: Be smarter about indexes that use expressions */
+          if( pIdx->aiColumn[j]==iCol || pIdx->aiColumn[j]==XN_EXPR ){
+            zFault = "indexed";
+          }
+        }
+      }
+      if( zFault ){
+        sqlite3DbFree(db, zErr);
+        zErr = sqlite3MPrintf(db, "cannot open %s column for writing", zFault);
+        rc = SQLITE_ERROR;
+        sqlite3BtreeLeaveAll(db);
+        goto blob_open_out;
+      }
+    }
+
+    pBlob->pStmt = (sqlite3_stmt *)sqlite3VdbeCreate(&sParse);
+    assert( pBlob->pStmt || db->mallocFailed );
+    if( pBlob->pStmt ){
+
+      /* This VDBE program seeks a btree cursor to the identified
+      ** db/table/row entry. The reason for using a vdbe program instead
+      ** of writing code to use the b-tree layer directly is that the
+      ** vdbe program will take advantage of the various transaction,
+      ** locking and error handling infrastructure built into the vdbe.
+      **
+      ** After seeking the cursor, the vdbe executes an OP_ResultRow.
+      ** Code external to the Vdbe then "borrows" the b-tree cursor and
+      ** uses it to implement the blob_read(), blob_write() and
+      ** blob_bytes() functions.
+      **
+      ** The sqlite3_blob_close() function finalizes the vdbe program,
+      ** which closes the b-tree cursor and (possibly) commits the
+      ** transaction.
+      */
+      static const int iLn = VDBE_OFFSET_LINENO(2);
+      static const VdbeOpList openBlob[] = {
+        {OP_TableLock,      0, 0, 0},  /* 0: Acquire a read or write lock */
+        {OP_OpenRead,       0, 0, 0},  /* 1: Open a cursor */
+        /* blobSeekToRow() will initialize r[1] to the desired rowid */
+        {OP_NotExists,      0, 5, 1},  /* 2: Seek the cursor to rowid=r[1] */
+        {OP_Column,         0, 0, 1},  /* 3  */
+        {OP_ResultRow,      1, 0, 0},  /* 4  */
+        {OP_Halt,           0, 0, 0},  /* 5  */
+      };
+      Vdbe *v = (Vdbe *)pBlob->pStmt;
+      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      VdbeOp *aOp;
+
+      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, wrFlag,
+                           pTab->pSchema->schema_cookie,
+                           pTab->pSchema->iGeneration);
+      sqlite3VdbeChangeP5(v, 1);
+      assert( sqlite3VdbeCurrentAddr(v)==2 || db->mallocFailed );
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(openBlob), openBlob, iLn);
+
+      /* Make sure a mutex is held on the table to be accessed */
+      sqlite3VdbeUsesBtree(v, iDb);
+
+      if( db->mallocFailed==0 ){
+        assert( aOp!=0 );
+        /* Configure the OP_TableLock instruction */
+#ifdef SQLITE_OMIT_SHARED_CACHE
+        aOp[0].opcode = OP_Noop;
+#else
+        aOp[0].p1 = iDb;
+        aOp[0].p2 = pTab->tnum;
+        aOp[0].p3 = wrFlag;
+        sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
+      }
+      if( db->mallocFailed==0 ){
+#endif
+
+        /* Remove either the OP_OpenWrite or OpenRead. Set the P2
+        ** parameter of the other to pTab->tnum.  */
+        if( wrFlag ) aOp[1].opcode = OP_OpenWrite;
+        aOp[1].p2 = pTab->tnum;
+        aOp[1].p3 = iDb;
+
+        /* Configure the number of columns. Configure the cursor to
+        ** think that the table has one more column than it really
+        ** does. An OP_Column to retrieve this imaginary column will
+        ** always return an SQL NULL. This is useful because it means
+        ** we can invoke OP_Column to fill in the vdbe cursors type
+        ** and offset cache without causing any IO.
+        */
+        aOp[1].p4type = P4_INT32;
+        aOp[1].p4.i = pTab->nCol+1;
+        aOp[3].p2 = pTab->nCol;
+
+        sParse.nVar = 0;
+        sParse.nMem = 1;
+        sParse.nTab = 1;
+        sqlite3VdbeMakeReady(v, &sParse);
+      }
+    }
+
+    pBlob->iCol = iCol;
+    pBlob->db = db;
+    sqlite3BtreeLeaveAll(db);
+    if( db->mallocFailed ){
+      goto blob_open_out;
+    }
+    rc = blobSeekToRow(pBlob, iRow, &zErr);
+    if( (++nAttempt)>=SQLITE_MAX_SCHEMA_RETRY || rc!=SQLITE_SCHEMA ) break;
+    sqlite3ParseObjectReset(&sParse);
+  }
+
+blob_open_out:
+  if( rc==SQLITE_OK && db->mallocFailed==0 ){
+    *ppBlob = (sqlite3_blob *)pBlob;
+  }else{
+    if( pBlob && pBlob->pStmt ) sqlite3VdbeFinalize((Vdbe *)pBlob->pStmt);
+    sqlite3DbFree(db, pBlob);
+  }
+  sqlite3ErrorWithMsg(db, rc, (zErr ? "%s" : (char*)0), zErr);
+  sqlite3DbFree(db, zErr);
+  sqlite3ParseObjectReset(&sParse);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Close a blob handle that was previously created using
+** sqlite3_blob_open().
+*/
+SQLITE_API int sqlite3_blob_close(sqlite3_blob *pBlob){
+  Incrblob *p = (Incrblob *)pBlob;
+  int rc;
+  sqlite3 *db;
+
+  if( p ){
+    sqlite3_stmt *pStmt = p->pStmt;
+    db = p->db;
+    sqlite3_mutex_enter(db->mutex);
+    sqlite3DbFree(db, p);
+    sqlite3_mutex_leave(db->mutex);
+    rc = sqlite3_finalize(pStmt);
+  }else{
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+
+/*
+** Perform a read or write operation on a blob
+*/
+static int blobReadWrite(
+  sqlite3_blob *pBlob,
+  void *z,
+  int n,
+  int iOffset,
+  int (*xCall)(BtCursor*, u32, u32, void*)
+){
+  int rc;
+  Incrblob *p = (Incrblob *)pBlob;
+  Vdbe *v;
+  sqlite3 *db;
+
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+  db = p->db;
+  sqlite3_mutex_enter(db->mutex);
+  v = (Vdbe*)p->pStmt;
+
+  if( n<0 || iOffset<0 || ((sqlite3_int64)iOffset+n)>p->nByte ){
+    /* Request is out of range. Return a transient error. */
+    rc = SQLITE_ERROR;
+  }else if( v==0 ){
+    /* If there is no statement handle, then the blob-handle has
+    ** already been invalidated. Return SQLITE_ABORT in this case.
+    */
+    rc = SQLITE_ABORT;
+  }else{
+    /* Call either BtreeData() or BtreePutData(). If SQLITE_ABORT is
+    ** returned, clean-up the statement handle.
+    */
+    assert( db == v->db );
+    sqlite3BtreeEnterCursor(p->pCsr);
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    if( xCall==sqlite3BtreePutData && db->xPreUpdateCallback ){
+      /* If a pre-update hook is registered and this is a write cursor,
+      ** invoke it here.
+      **
+      ** TODO: The preupdate-hook is passed SQLITE_DELETE, even though this
+      ** operation should really be an SQLITE_UPDATE. This is probably
+      ** incorrect, but is convenient because at this point the new.* values
+      ** are not easily obtainable. And for the sessions module, an
+      ** SQLITE_UPDATE where the PK columns do not change is handled in the
+      ** same way as an SQLITE_DELETE (the SQLITE_DELETE code is actually
+      ** slightly more efficient). Since you cannot write to a PK column
+      ** using the incremental-blob API, this works. For the sessions module
+      ** anyhow.
+      */
+      sqlite3_int64 iKey;
+      iKey = sqlite3BtreeIntegerKey(p->pCsr);
+      assert( v->apCsr[0]!=0 );
+      assert( v->apCsr[0]->eCurType==CURTYPE_BTREE );
+      sqlite3VdbePreUpdateHook(
+          v, v->apCsr[0], SQLITE_DELETE, p->zDb, p->pTab, iKey, -1, p->iCol
+      );
+    }
+#endif
+
+    rc = xCall(p->pCsr, iOffset+p->iOffset, n, z);
+    sqlite3BtreeLeaveCursor(p->pCsr);
+    if( rc==SQLITE_ABORT ){
+      sqlite3VdbeFinalize(v);
+      p->pStmt = 0;
+    }else{
+      v->rc = rc;
+    }
+  }
+  sqlite3Error(db, rc);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Read data from a blob handle.
+*/
+SQLITE_API int sqlite3_blob_read(sqlite3_blob *pBlob, void *z, int n, int iOffset){
+  return blobReadWrite(pBlob, z, n, iOffset, sqlite3BtreePayloadChecked);
+}
+
+/*
+** Write data to a blob handle.
+*/
+SQLITE_API int sqlite3_blob_write(sqlite3_blob *pBlob, const void *z, int n, int iOffset){
+  return blobReadWrite(pBlob, (void *)z, n, iOffset, sqlite3BtreePutData);
+}
+
+/*
+** Query a blob handle for the size of the data.
+**
+** The Incrblob.nByte field is fixed for the lifetime of the Incrblob
+** so no mutex is required for access.
+*/
+SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *pBlob){
+  Incrblob *p = (Incrblob *)pBlob;
+  return (p && p->pStmt) ? p->nByte : 0;
+}
+
+/*
+** Move an existing blob handle to point to a different row of the same
+** database table.
+**
+** If an error occurs, or if the specified row does not exist or does not
+** contain a blob or text value, then an error code is returned and the
+** database handle error code and message set. If this happens, then all
+** subsequent calls to sqlite3_blob_xxx() functions (except blob_close())
+** immediately return SQLITE_ABORT.
+*/
+SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *pBlob, sqlite3_int64 iRow){
+  int rc;
+  Incrblob *p = (Incrblob *)pBlob;
+  sqlite3 *db;
+
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+  db = p->db;
+  sqlite3_mutex_enter(db->mutex);
+
+  if( p->pStmt==0 ){
+    /* If there is no statement handle, then the blob-handle has
+    ** already been invalidated. Return SQLITE_ABORT in this case.
+    */
+    rc = SQLITE_ABORT;
+  }else{
+    char *zErr;
+    ((Vdbe*)p->pStmt)->rc = SQLITE_OK;
+    rc = blobSeekToRow(p, iRow, &zErr);
+    if( rc!=SQLITE_OK ){
+      sqlite3ErrorWithMsg(db, rc, (zErr ? "%s" : (char*)0), zErr);
+      sqlite3DbFree(db, zErr);
+    }
+    assert( rc!=SQLITE_SCHEMA );
+  }
+
+  rc = sqlite3ApiExit(db, rc);
+  assert( rc==SQLITE_OK || p->pStmt==0 );
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+#endif /* #ifndef SQLITE_OMIT_INCRBLOB */
+
+/************** End of vdbeblob.c ********************************************/
+/************** Begin file vdbesort.c ****************************************/
+/*
+** 2011-07-09
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code for the VdbeSorter object, used in concert with
+** a VdbeCursor to sort large numbers of keys for CREATE INDEX statements
+** or by SELECT statements with ORDER BY clauses that cannot be satisfied
+** using indexes and without LIMIT clauses.
+**
+** The VdbeSorter object implements a multi-threaded external merge sort
+** algorithm that is efficient even if the number of elements being sorted
+** exceeds the available memory.
+**
+** Here is the (internal, non-API) interface between this module and the
+** rest of the SQLite system:
+**
+**    sqlite3VdbeSorterInit()       Create a new VdbeSorter object.
+**
+**    sqlite3VdbeSorterWrite()      Add a single new row to the VdbeSorter
+**                                  object.  The row is a binary blob in the
+**                                  OP_MakeRecord format that contains both
+**                                  the ORDER BY key columns and result columns
+**                                  in the case of a SELECT w/ ORDER BY, or
+**                                  the complete record for an index entry
+**                                  in the case of a CREATE INDEX.
+**
+**    sqlite3VdbeSorterRewind()     Sort all content previously added.
+**                                  Position the read cursor on the
+**                                  first sorted element.
+**
+**    sqlite3VdbeSorterNext()       Advance the read cursor to the next sorted
+**                                  element.
+**
+**    sqlite3VdbeSorterRowkey()     Return the complete binary blob for the
+**                                  row currently under the read cursor.
+**
+**    sqlite3VdbeSorterCompare()    Compare the binary blob for the row
+**                                  currently under the read cursor against
+**                                  another binary blob X and report if
+**                                  X is strictly less than the read cursor.
+**                                  Used to enforce uniqueness in a
+**                                  CREATE UNIQUE INDEX statement.
+**
+**    sqlite3VdbeSorterClose()      Close the VdbeSorter object and reclaim
+**                                  all resources.
+**
+**    sqlite3VdbeSorterReset()      Refurbish the VdbeSorter for reuse.  This
+**                                  is like Close() followed by Init() only
+**                                  much faster.
+**
+** The interfaces above must be called in a particular order.  Write() can
+** only occur in between Init()/Reset() and Rewind().  Next(), Rowkey(), and
+** Compare() can only occur in between Rewind() and Close()/Reset(). i.e.
+**
+**   Init()
+**   for each record: Write()
+**   Rewind()
+**     Rowkey()/Compare()
+**   Next()
+**   Close()
+**
+** Algorithm:
+**
+** Records passed to the sorter via calls to Write() are initially held
+** unsorted in main memory. Assuming the amount of memory used never exceeds
+** a threshold, when Rewind() is called the set of records is sorted using
+** an in-memory merge sort. In this case, no temporary files are required
+** and subsequent calls to Rowkey(), Next() and Compare() read records
+** directly from main memory.
+**
+** If the amount of space used to store records in main memory exceeds the
+** threshold, then the set of records currently in memory are sorted and
+** written to a temporary file in "Packed Memory Array" (PMA) format.
+** A PMA created at this point is known as a "level-0 PMA". Higher levels
+** of PMAs may be created by merging existing PMAs together - for example
+** merging two or more level-0 PMAs together creates a level-1 PMA.
+**
+** The threshold for the amount of main memory to use before flushing
+** records to a PMA is roughly the same as the limit configured for the
+** page-cache of the main database. Specifically, the threshold is set to
+** the value returned by "PRAGMA main.page_size" multiplied by
+** that returned by "PRAGMA main.cache_size", in bytes.
+**
+** If the sorter is running in single-threaded mode, then all PMAs generated
+** are appended to a single temporary file. Or, if the sorter is running in
+** multi-threaded mode then up to (N+1) temporary files may be opened, where
+** N is the configured number of worker threads. In this case, instead of
+** sorting the records and writing the PMA to a temporary file itself, the
+** calling thread usually launches a worker thread to do so. Except, if
+** there are already N worker threads running, the main thread does the work
+** itself.
+**
+** The sorter is running in multi-threaded mode if (a) the library was built
+** with pre-processor symbol SQLITE_MAX_WORKER_THREADS set to a value greater
+** than zero, and (b) worker threads have been enabled at runtime by calling
+** "PRAGMA threads=N" with some value of N greater than 0.
+**
+** When Rewind() is called, any data remaining in memory is flushed to a
+** final PMA. So at this point the data is stored in some number of sorted
+** PMAs within temporary files on disk.
+**
+** If there are fewer than SORTER_MAX_MERGE_COUNT PMAs in total and the
+** sorter is running in single-threaded mode, then these PMAs are merged
+** incrementally as keys are retrieved from the sorter by the VDBE.  The
+** MergeEngine object, described in further detail below, performs this
+** merge.
+**
+** Or, if running in multi-threaded mode, then a background thread is
+** launched to merge the existing PMAs. Once the background thread has
+** merged T bytes of data into a single sorted PMA, the main thread
+** begins reading keys from that PMA while the background thread proceeds
+** with merging the next T bytes of data. And so on.
+**
+** Parameter T is set to half the value of the memory threshold used
+** by Write() above to determine when to create a new PMA.
+**
+** If there are more than SORTER_MAX_MERGE_COUNT PMAs in total when
+** Rewind() is called, then a hierarchy of incremental-merges is used.
+** First, T bytes of data from the first SORTER_MAX_MERGE_COUNT PMAs on
+** disk are merged together. Then T bytes of data from the second set, and
+** so on, such that no operation ever merges more than SORTER_MAX_MERGE_COUNT
+** PMAs at a time. This done is to improve locality.
+**
+** If running in multi-threaded mode and there are more than
+** SORTER_MAX_MERGE_COUNT PMAs on disk when Rewind() is called, then more
+** than one background thread may be created. Specifically, there may be
+** one background thread for each temporary file on disk, and one background
+** thread to merge the output of each of the others to a single PMA for
+** the main thread to read from.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+/*
+** If SQLITE_DEBUG_SORTER_THREADS is defined, this module outputs various
+** messages to stderr that may be helpful in understanding the performance
+** characteristics of the sorter in multi-threaded mode.
+*/
+#if 0
+# define SQLITE_DEBUG_SORTER_THREADS 1
+#endif
+
+/*
+** Hard-coded maximum amount of data to accumulate in memory before flushing
+** to a level 0 PMA. The purpose of this limit is to prevent various integer
+** overflows. 512MiB.
+*/
+#define SQLITE_MAX_PMASZ    (1<<29)
+
+/*
+** Private objects used by the sorter
+*/
+typedef struct MergeEngine MergeEngine;     /* Merge PMAs together */
+typedef struct PmaReader PmaReader;         /* Incrementally read one PMA */
+typedef struct PmaWriter PmaWriter;         /* Incrementally write one PMA */
+typedef struct SorterRecord SorterRecord;   /* A record being sorted */
+typedef struct SortSubtask SortSubtask;     /* A sub-task in the sort process */
+typedef struct SorterFile SorterFile;       /* Temporary file object wrapper */
+typedef struct SorterList SorterList;       /* In-memory list of records */
+typedef struct IncrMerger IncrMerger;       /* Read & merge multiple PMAs */
+
+/*
+** A container for a temp file handle and the current amount of data
+** stored in the file.
+*/
+struct SorterFile {
+  sqlite3_file *pFd;              /* File handle */
+  i64 iEof;                       /* Bytes of data stored in pFd */
+};
+
+/*
+** An in-memory list of objects to be sorted.
+**
+** If aMemory==0 then each object is allocated separately and the objects
+** are connected using SorterRecord.u.pNext.  If aMemory!=0 then all objects
+** are stored in the aMemory[] bulk memory, one right after the other, and
+** are connected using SorterRecord.u.iNext.
+*/
+struct SorterList {
+  SorterRecord *pList;            /* Linked list of records */
+  u8 *aMemory;                    /* If non-NULL, bulk memory to hold pList */
+  i64 szPMA;                      /* Size of pList as PMA in bytes */
+};
+
+/*
+** The MergeEngine object is used to combine two or more smaller PMAs into
+** one big PMA using a merge operation.  Separate PMAs all need to be
+** combined into one big PMA in order to be able to step through the sorted
+** records in order.
+**
+** The aReadr[] array contains a PmaReader object for each of the PMAs being
+** merged.  An aReadr[] object either points to a valid key or else is at EOF.
+** ("EOF" means "End Of File".  When aReadr[] is at EOF there is no more data.)
+** For the purposes of the paragraphs below, we assume that the array is
+** actually N elements in size, where N is the smallest power of 2 greater
+** to or equal to the number of PMAs being merged. The extra aReadr[] elements
+** are treated as if they are empty (always at EOF).
+**
+** The aTree[] array is also N elements in size. The value of N is stored in
+** the MergeEngine.nTree variable.
+**
+** The final (N/2) elements of aTree[] contain the results of comparing
+** pairs of PMA keys together. Element i contains the result of
+** comparing aReadr[2*i-N] and aReadr[2*i-N+1]. Whichever key is smaller, the
+** aTree element is set to the index of it.
+**
+** For the purposes of this comparison, EOF is considered greater than any
+** other key value. If the keys are equal (only possible with two EOF
+** values), it doesn't matter which index is stored.
+**
+** The (N/4) elements of aTree[] that precede the final (N/2) described
+** above contains the index of the smallest of each block of 4 PmaReaders
+** And so on. So that aTree[1] contains the index of the PmaReader that
+** currently points to the smallest key value. aTree[0] is unused.
+**
+** Example:
+**
+**     aReadr[0] -> Banana
+**     aReadr[1] -> Feijoa
+**     aReadr[2] -> Elderberry
+**     aReadr[3] -> Currant
+**     aReadr[4] -> Grapefruit
+**     aReadr[5] -> Apple
+**     aReadr[6] -> Durian
+**     aReadr[7] -> EOF
+**
+**     aTree[] = { X, 5   0, 5    0, 3, 5, 6 }
+**
+** The current element is "Apple" (the value of the key indicated by
+** PmaReader 5). When the Next() operation is invoked, PmaReader 5 will
+** be advanced to the next key in its segment. Say the next key is
+** "Eggplant":
+**
+**     aReadr[5] -> Eggplant
+**
+** The contents of aTree[] are updated first by comparing the new PmaReader
+** 5 key to the current key of PmaReader 4 (still "Grapefruit"). The PmaReader
+** 5 value is still smaller, so aTree[6] is set to 5. And so on up the tree.
+** The value of PmaReader 6 - "Durian" - is now smaller than that of PmaReader
+** 5, so aTree[3] is set to 6. Key 0 is smaller than key 6 (Banana<Durian),
+** so the value written into element 1 of the array is 0. As follows:
+**
+**     aTree[] = { X, 0   0, 6    0, 3, 5, 6 }
+**
+** In other words, each time we advance to the next sorter element, log2(N)
+** key comparison operations are required, where N is the number of segments
+** being merged (rounded up to the next power of 2).
+*/
+struct MergeEngine {
+  int nTree;                 /* Used size of aTree/aReadr (power of 2) */
+  SortSubtask *pTask;        /* Used by this thread only */
+  int *aTree;                /* Current state of incremental merge */
+  PmaReader *aReadr;         /* Array of PmaReaders to merge data from */
+};
+
+/*
+** This object represents a single thread of control in a sort operation.
+** Exactly VdbeSorter.nTask instances of this object are allocated
+** as part of each VdbeSorter object. Instances are never allocated any
+** other way. VdbeSorter.nTask is set to the number of worker threads allowed
+** (see SQLITE_CONFIG_WORKER_THREADS) plus one (the main thread).  Thus for
+** single-threaded operation, there is exactly one instance of this object
+** and for multi-threaded operation there are two or more instances.
+**
+** Essentially, this structure contains all those fields of the VdbeSorter
+** structure for which each thread requires a separate instance. For example,
+** each thread requeries its own UnpackedRecord object to unpack records in
+** as part of comparison operations.
+**
+** Before a background thread is launched, variable bDone is set to 0. Then,
+** right before it exits, the thread itself sets bDone to 1. This is used for
+** two purposes:
+**
+**   1. When flushing the contents of memory to a level-0 PMA on disk, to
+**      attempt to select a SortSubtask for which there is not already an
+**      active background thread (since doing so causes the main thread
+**      to block until it finishes).
+**
+**   2. If SQLITE_DEBUG_SORTER_THREADS is defined, to determine if a call
+**      to sqlite3ThreadJoin() is likely to block. Cases that are likely to
+**      block provoke debugging output.
+**
+** In both cases, the effects of the main thread seeing (bDone==0) even
+** after the thread has finished are not dire. So we don't worry about
+** memory barriers and such here.
+*/
+typedef int (*SorterCompare)(SortSubtask*,int*,const void*,int,const void*,int);
+struct SortSubtask {
+  SQLiteThread *pThread;          /* Background thread, if any */
+  int bDone;                      /* Set if thread is finished but not joined */
+  int nPMA;                       /* Number of PMAs currently in file */
+  VdbeSorter *pSorter;            /* Sorter that owns this sub-task */
+  UnpackedRecord *pUnpacked;      /* Space to unpack a record */
+  SorterList list;                /* List for thread to write to a PMA */
+  SorterCompare xCompare;         /* Compare function to use */
+  SorterFile file;                /* Temp file for level-0 PMAs */
+  SorterFile file2;               /* Space for other PMAs */
+};
+
+
+/*
+** Main sorter structure. A single instance of this is allocated for each
+** sorter cursor created by the VDBE.
+**
+** mxKeysize:
+**   As records are added to the sorter by calls to sqlite3VdbeSorterWrite(),
+**   this variable is updated so as to be set to the size on disk of the
+**   largest record in the sorter.
+*/
+struct VdbeSorter {
+  int mnPmaSize;                  /* Minimum PMA size, in bytes */
+  int mxPmaSize;                  /* Maximum PMA size, in bytes.  0==no limit */
+  int mxKeysize;                  /* Largest serialized key seen so far */
+  int pgsz;                       /* Main database page size */
+  PmaReader *pReader;             /* Readr data from here after Rewind() */
+  MergeEngine *pMerger;           /* Or here, if bUseThreads==0 */
+  sqlite3 *db;                    /* Database connection */
+  KeyInfo *pKeyInfo;              /* How to compare records */
+  UnpackedRecord *pUnpacked;      /* Used by VdbeSorterCompare() */
+  SorterList list;                /* List of in-memory records */
+  int iMemory;                    /* Offset of free space in list.aMemory */
+  int nMemory;                    /* Size of list.aMemory allocation in bytes */
+  u8 bUsePMA;                     /* True if one or more PMAs created */
+  u8 bUseThreads;                 /* True to use background threads */
+  u8 iPrev;                       /* Previous thread used to flush PMA */
+  u8 nTask;                       /* Size of aTask[] array */
+  u8 typeMask;
+  SortSubtask aTask[1];           /* One or more subtasks */
+};
+
+#define SORTER_TYPE_INTEGER 0x01
+#define SORTER_TYPE_TEXT    0x02
+
+/*
+** An instance of the following object is used to read records out of a
+** PMA, in sorted order.  The next key to be read is cached in nKey/aKey.
+** aKey might point into aMap or into aBuffer.  If neither of those locations
+** contain a contiguous representation of the key, then aAlloc is allocated
+** and the key is copied into aAlloc and aKey is made to point to aAlloc.
+**
+** pFd==0 at EOF.
+*/
+struct PmaReader {
+  i64 iReadOff;               /* Current read offset */
+  i64 iEof;                   /* 1 byte past EOF for this PmaReader */
+  int nAlloc;                 /* Bytes of space at aAlloc */
+  int nKey;                   /* Number of bytes in key */
+  sqlite3_file *pFd;          /* File handle we are reading from */
+  u8 *aAlloc;                 /* Space for aKey if aBuffer and pMap wont work */
+  u8 *aKey;                   /* Pointer to current key */
+  u8 *aBuffer;                /* Current read buffer */
+  int nBuffer;                /* Size of read buffer in bytes */
+  u8 *aMap;                   /* Pointer to mapping of entire file */
+  IncrMerger *pIncr;          /* Incremental merger */
+};
+
+/*
+** Normally, a PmaReader object iterates through an existing PMA stored
+** within a temp file. However, if the PmaReader.pIncr variable points to
+** an object of the following type, it may be used to iterate/merge through
+** multiple PMAs simultaneously.
+**
+** There are two types of IncrMerger object - single (bUseThread==0) and
+** multi-threaded (bUseThread==1).
+**
+** A multi-threaded IncrMerger object uses two temporary files - aFile[0]
+** and aFile[1]. Neither file is allowed to grow to more than mxSz bytes in
+** size. When the IncrMerger is initialized, it reads enough data from
+** pMerger to populate aFile[0]. It then sets variables within the
+** corresponding PmaReader object to read from that file and kicks off
+** a background thread to populate aFile[1] with the next mxSz bytes of
+** sorted record data from pMerger.
+**
+** When the PmaReader reaches the end of aFile[0], it blocks until the
+** background thread has finished populating aFile[1]. It then exchanges
+** the contents of the aFile[0] and aFile[1] variables within this structure,
+** sets the PmaReader fields to read from the new aFile[0] and kicks off
+** another background thread to populate the new aFile[1]. And so on, until
+** the contents of pMerger are exhausted.
+**
+** A single-threaded IncrMerger does not open any temporary files of its
+** own. Instead, it has exclusive access to mxSz bytes of space beginning
+** at offset iStartOff of file pTask->file2. And instead of using a
+** background thread to prepare data for the PmaReader, with a single
+** threaded IncrMerger the allocate part of pTask->file2 is "refilled" with
+** keys from pMerger by the calling thread whenever the PmaReader runs out
+** of data.
+*/
+struct IncrMerger {
+  SortSubtask *pTask;             /* Task that owns this merger */
+  MergeEngine *pMerger;           /* Merge engine thread reads data from */
+  i64 iStartOff;                  /* Offset to start writing file at */
+  int mxSz;                       /* Maximum bytes of data to store */
+  int bEof;                       /* Set to true when merge is finished */
+  int bUseThread;                 /* True to use a bg thread for this object */
+  SorterFile aFile[2];            /* aFile[0] for reading, [1] for writing */
+};
+
+/*
+** An instance of this object is used for writing a PMA.
+**
+** The PMA is written one record at a time.  Each record is of an arbitrary
+** size.  But I/O is more efficient if it occurs in page-sized blocks where
+** each block is aligned on a page boundary.  This object caches writes to
+** the PMA so that aligned, page-size blocks are written.
+*/
+struct PmaWriter {
+  int eFWErr;                     /* Non-zero if in an error state */
+  u8 *aBuffer;                    /* Pointer to write buffer */
+  int nBuffer;                    /* Size of write buffer in bytes */
+  int iBufStart;                  /* First byte of buffer to write */
+  int iBufEnd;                    /* Last byte of buffer to write */
+  i64 iWriteOff;                  /* Offset of start of buffer in file */
+  sqlite3_file *pFd;              /* File handle to write to */
+};
+
+/*
+** This object is the header on a single record while that record is being
+** held in memory and prior to being written out as part of a PMA.
+**
+** How the linked list is connected depends on how memory is being managed
+** by this module. If using a separate allocation for each in-memory record
+** (VdbeSorter.list.aMemory==0), then the list is always connected using the
+** SorterRecord.u.pNext pointers.
+**
+** Or, if using the single large allocation method (VdbeSorter.list.aMemory!=0),
+** then while records are being accumulated the list is linked using the
+** SorterRecord.u.iNext offset. This is because the aMemory[] array may
+** be sqlite3Realloc()ed while records are being accumulated. Once the VM
+** has finished passing records to the sorter, or when the in-memory buffer
+** is full, the list is sorted. As part of the sorting process, it is
+** converted to use the SorterRecord.u.pNext pointers. See function
+** vdbeSorterSort() for details.
+*/
+struct SorterRecord {
+  int nVal;                       /* Size of the record in bytes */
+  union {
+    SorterRecord *pNext;          /* Pointer to next record in list */
+    int iNext;                    /* Offset within aMemory of next record */
+  } u;
+  /* The data for the record immediately follows this header */
+};
+
+/* Return a pointer to the buffer containing the record data for SorterRecord
+** object p. Should be used as if:
+**
+**   void *SRVAL(SorterRecord *p) { return (void*)&p[1]; }
+*/
+#define SRVAL(p) ((void*)((SorterRecord*)(p) + 1))
+
+
+/* Maximum number of PMAs that a single MergeEngine can merge */
+#define SORTER_MAX_MERGE_COUNT 16
+
+static int vdbeIncrSwap(IncrMerger*);
+static void vdbeIncrFree(IncrMerger *);
+
+/*
+** Free all memory belonging to the PmaReader object passed as the
+** argument. All structure fields are set to zero before returning.
+*/
+static void vdbePmaReaderClear(PmaReader *pReadr){
+  sqlite3_free(pReadr->aAlloc);
+  sqlite3_free(pReadr->aBuffer);
+  if( pReadr->aMap ) sqlite3OsUnfetch(pReadr->pFd, 0, pReadr->aMap);
+  vdbeIncrFree(pReadr->pIncr);
+  memset(pReadr, 0, sizeof(PmaReader));
+}
+
+/*
+** Read the next nByte bytes of data from the PMA p.
+** If successful, set *ppOut to point to a buffer containing the data
+** and return SQLITE_OK. Otherwise, if an error occurs, return an SQLite
+** error code.
+**
+** The buffer returned in *ppOut is only valid until the
+** next call to this function.
+*/
+static int vdbePmaReadBlob(
+  PmaReader *p,                   /* PmaReader from which to take the blob */
+  int nByte,                      /* Bytes of data to read */
+  u8 **ppOut                      /* OUT: Pointer to buffer containing data */
+){
+  int iBuf;                       /* Offset within buffer to read from */
+  int nAvail;                     /* Bytes of data available in buffer */
+
+  if( p->aMap ){
+    *ppOut = &p->aMap[p->iReadOff];
+    p->iReadOff += nByte;
+    return SQLITE_OK;
+  }
+
+  assert( p->aBuffer );
+
+  /* If there is no more data to be read from the buffer, read the next
+  ** p->nBuffer bytes of data from the file into it. Or, if there are less
+  ** than p->nBuffer bytes remaining in the PMA, read all remaining data.  */
+  iBuf = p->iReadOff % p->nBuffer;
+  if( iBuf==0 ){
+    int nRead;                    /* Bytes to read from disk */
+    int rc;                       /* sqlite3OsRead() return code */
+
+    /* Determine how many bytes of data to read. */
+    if( (p->iEof - p->iReadOff) > (i64)p->nBuffer ){
+      nRead = p->nBuffer;
+    }else{
+      nRead = (int)(p->iEof - p->iReadOff);
+    }
+    assert( nRead>0 );
+
+    /* Readr data from the file. Return early if an error occurs. */
+    rc = sqlite3OsRead(p->pFd, p->aBuffer, nRead, p->iReadOff);
+    assert( rc!=SQLITE_IOERR_SHORT_READ );
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  nAvail = p->nBuffer - iBuf;
+
+  if( nByte<=nAvail ){
+    /* The requested data is available in the in-memory buffer. In this
+    ** case there is no need to make a copy of the data, just return a
+    ** pointer into the buffer to the caller.  */
+    *ppOut = &p->aBuffer[iBuf];
+    p->iReadOff += nByte;
+  }else{
+    /* The requested data is not all available in the in-memory buffer.
+    ** In this case, allocate space at p->aAlloc[] to copy the requested
+    ** range into. Then return a copy of pointer p->aAlloc to the caller.  */
+    int nRem;                     /* Bytes remaining to copy */
+
+    /* Extend the p->aAlloc[] allocation if required. */
+    if( p->nAlloc<nByte ){
+      u8 *aNew;
+      sqlite3_int64 nNew = MAX(128, 2*(sqlite3_int64)p->nAlloc);
+      while( nByte>nNew ) nNew = nNew*2;
+      aNew = sqlite3Realloc(p->aAlloc, nNew);
+      if( !aNew ) return SQLITE_NOMEM_BKPT;
+      p->nAlloc = nNew;
+      p->aAlloc = aNew;
+    }
+
+    /* Copy as much data as is available in the buffer into the start of
+    ** p->aAlloc[].  */
+    memcpy(p->aAlloc, &p->aBuffer[iBuf], nAvail);
+    p->iReadOff += nAvail;
+    nRem = nByte - nAvail;
+
+    /* The following loop copies up to p->nBuffer bytes per iteration into
+    ** the p->aAlloc[] buffer.  */
+    while( nRem>0 ){
+      int rc;                     /* vdbePmaReadBlob() return code */
+      int nCopy;                  /* Number of bytes to copy */
+      u8 *aNext = 0;              /* Pointer to buffer to copy data from */
+
+      nCopy = nRem;
+      if( nRem>p->nBuffer ) nCopy = p->nBuffer;
+      rc = vdbePmaReadBlob(p, nCopy, &aNext);
+      if( rc!=SQLITE_OK ) return rc;
+      assert( aNext!=p->aAlloc );
+      assert( aNext!=0 );
+      memcpy(&p->aAlloc[nByte - nRem], aNext, nCopy);
+      nRem -= nCopy;
+    }
+
+    *ppOut = p->aAlloc;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Read a varint from the stream of data accessed by p. Set *pnOut to
+** the value read.
+*/
+static int vdbePmaReadVarint(PmaReader *p, u64 *pnOut){
+  int iBuf;
+
+  if( p->aMap ){
+    p->iReadOff += sqlite3GetVarint(&p->aMap[p->iReadOff], pnOut);
+  }else{
+    iBuf = p->iReadOff % p->nBuffer;
+    if( iBuf && (p->nBuffer-iBuf)>=9 ){
+      p->iReadOff += sqlite3GetVarint(&p->aBuffer[iBuf], pnOut);
+    }else{
+      u8 aVarint[16], *a;
+      int i = 0, rc;
+      do{
+        rc = vdbePmaReadBlob(p, 1, &a);
+        if( rc ) return rc;
+        aVarint[(i++)&0xf] = a[0];
+      }while( (a[0]&0x80)!=0 );
+      sqlite3GetVarint(aVarint, pnOut);
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Attempt to memory map file pFile. If successful, set *pp to point to the
+** new mapping and return SQLITE_OK. If the mapping is not attempted
+** (because the file is too large or the VFS layer is configured not to use
+** mmap), return SQLITE_OK and set *pp to NULL.
+**
+** Or, if an error occurs, return an SQLite error code. The final value of
+** *pp is undefined in this case.
+*/
+static int vdbeSorterMapFile(SortSubtask *pTask, SorterFile *pFile, u8 **pp){
+  int rc = SQLITE_OK;
+  if( pFile->iEof<=(i64)(pTask->pSorter->db->nMaxSorterMmap) ){
+    sqlite3_file *pFd = pFile->pFd;
+    if( pFd->pMethods->iVersion>=3 ){
+      rc = sqlite3OsFetch(pFd, 0, (int)pFile->iEof, (void**)pp);
+      testcase( rc!=SQLITE_OK );
+    }
+  }
+  return rc;
+}
+
+/*
+** Attach PmaReader pReadr to file pFile (if it is not already attached to
+** that file) and seek it to offset iOff within the file.  Return SQLITE_OK
+** if successful, or an SQLite error code if an error occurs.
+*/
+static int vdbePmaReaderSeek(
+  SortSubtask *pTask,             /* Task context */
+  PmaReader *pReadr,              /* Reader whose cursor is to be moved */
+  SorterFile *pFile,              /* Sorter file to read from */
+  i64 iOff                        /* Offset in pFile */
+){
+  int rc = SQLITE_OK;
+
+  assert( pReadr->pIncr==0 || pReadr->pIncr->bEof==0 );
+
+  if( sqlite3FaultSim(201) ) return SQLITE_IOERR_READ;
+  if( pReadr->aMap ){
+    sqlite3OsUnfetch(pReadr->pFd, 0, pReadr->aMap);
+    pReadr->aMap = 0;
+  }
+  pReadr->iReadOff = iOff;
+  pReadr->iEof = pFile->iEof;
+  pReadr->pFd = pFile->pFd;
+
+  rc = vdbeSorterMapFile(pTask, pFile, &pReadr->aMap);
+  if( rc==SQLITE_OK && pReadr->aMap==0 ){
+    int pgsz = pTask->pSorter->pgsz;
+    int iBuf = pReadr->iReadOff % pgsz;
+    if( pReadr->aBuffer==0 ){
+      pReadr->aBuffer = (u8*)sqlite3Malloc(pgsz);
+      if( pReadr->aBuffer==0 ) rc = SQLITE_NOMEM_BKPT;
+      pReadr->nBuffer = pgsz;
+    }
+    if( rc==SQLITE_OK && iBuf ){
+      int nRead = pgsz - iBuf;
+      if( (pReadr->iReadOff + nRead) > pReadr->iEof ){
+        nRead = (int)(pReadr->iEof - pReadr->iReadOff);
+      }
+      rc = sqlite3OsRead(
+          pReadr->pFd, &pReadr->aBuffer[iBuf], nRead, pReadr->iReadOff
+      );
+      testcase( rc!=SQLITE_OK );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Advance PmaReader pReadr to the next key in its PMA. Return SQLITE_OK if
+** no error occurs, or an SQLite error code if one does.
+*/
+static int vdbePmaReaderNext(PmaReader *pReadr){
+  int rc = SQLITE_OK;             /* Return Code */
+  u64 nRec = 0;                   /* Size of record in bytes */
+
+
+  if( pReadr->iReadOff>=pReadr->iEof ){
+    IncrMerger *pIncr = pReadr->pIncr;
+    int bEof = 1;
+    if( pIncr ){
+      rc = vdbeIncrSwap(pIncr);
+      if( rc==SQLITE_OK && pIncr->bEof==0 ){
+        rc = vdbePmaReaderSeek(
+            pIncr->pTask, pReadr, &pIncr->aFile[0], pIncr->iStartOff
+        );
+        bEof = 0;
+      }
+    }
+
+    if( bEof ){
+      /* This is an EOF condition */
+      vdbePmaReaderClear(pReadr);
+      testcase( rc!=SQLITE_OK );
+      return rc;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = vdbePmaReadVarint(pReadr, &nRec);
+  }
+  if( rc==SQLITE_OK ){
+    pReadr->nKey = (int)nRec;
+    rc = vdbePmaReadBlob(pReadr, (int)nRec, &pReadr->aKey);
+    testcase( rc!=SQLITE_OK );
+  }
+
+  return rc;
+}
+
+/*
+** Initialize PmaReader pReadr to scan through the PMA stored in file pFile
+** starting at offset iStart and ending at offset iEof-1. This function
+** leaves the PmaReader pointing to the first key in the PMA (or EOF if the
+** PMA is empty).
+**
+** If the pnByte parameter is NULL, then it is assumed that the file
+** contains a single PMA, and that that PMA omits the initial length varint.
+*/
+static int vdbePmaReaderInit(
+  SortSubtask *pTask,             /* Task context */
+  SorterFile *pFile,              /* Sorter file to read from */
+  i64 iStart,                     /* Start offset in pFile */
+  PmaReader *pReadr,              /* PmaReader to populate */
+  i64 *pnByte                     /* IN/OUT: Increment this value by PMA size */
+){
+  int rc;
+
+  assert( pFile->iEof>iStart );
+  assert( pReadr->aAlloc==0 && pReadr->nAlloc==0 );
+  assert( pReadr->aBuffer==0 );
+  assert( pReadr->aMap==0 );
+
+  rc = vdbePmaReaderSeek(pTask, pReadr, pFile, iStart);
+  if( rc==SQLITE_OK ){
+    u64 nByte = 0;                 /* Size of PMA in bytes */
+    rc = vdbePmaReadVarint(pReadr, &nByte);
+    pReadr->iEof = pReadr->iReadOff + nByte;
+    *pnByte += nByte;
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = vdbePmaReaderNext(pReadr);
+  }
+  return rc;
+}
+
+/*
+** A version of vdbeSorterCompare() that assumes that it has already been
+** determined that the first field of key1 is equal to the first field of
+** key2.
+*/
+static int vdbeSorterCompareTail(
+  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
+  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
+  const void *pKey1, int nKey1,   /* Left side of comparison */
+  const void *pKey2, int nKey2    /* Right side of comparison */
+){
+  UnpackedRecord *r2 = pTask->pUnpacked;
+  if( *pbKey2Cached==0 ){
+    sqlite3VdbeRecordUnpack(pTask->pSorter->pKeyInfo, nKey2, pKey2, r2);
+    *pbKey2Cached = 1;
+  }
+  return sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, r2, 1);
+}
+
+/*
+** Compare key1 (buffer pKey1, size nKey1 bytes) with key2 (buffer pKey2,
+** size nKey2 bytes). Use (pTask->pKeyInfo) for the collation sequences
+** used by the comparison. Return the result of the comparison.
+**
+** If IN/OUT parameter *pbKey2Cached is true when this function is called,
+** it is assumed that (pTask->pUnpacked) contains the unpacked version
+** of key2. If it is false, (pTask->pUnpacked) is populated with the unpacked
+** version of key2 and *pbKey2Cached set to true before returning.
+**
+** If an OOM error is encountered, (pTask->pUnpacked->error_rc) is set
+** to SQLITE_NOMEM.
+*/
+static int vdbeSorterCompare(
+  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
+  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
+  const void *pKey1, int nKey1,   /* Left side of comparison */
+  const void *pKey2, int nKey2    /* Right side of comparison */
+){
+  UnpackedRecord *r2 = pTask->pUnpacked;
+  if( !*pbKey2Cached ){
+    sqlite3VdbeRecordUnpack(pTask->pSorter->pKeyInfo, nKey2, pKey2, r2);
+    *pbKey2Cached = 1;
+  }
+  return sqlite3VdbeRecordCompare(nKey1, pKey1, r2);
+}
+
+/*
+** A specially optimized version of vdbeSorterCompare() that assumes that
+** the first field of each key is a TEXT value and that the collation
+** sequence to compare them with is BINARY.
+*/
+static int vdbeSorterCompareText(
+  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
+  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
+  const void *pKey1, int nKey1,   /* Left side of comparison */
+  const void *pKey2, int nKey2    /* Right side of comparison */
+){
+  const u8 * const p1 = (const u8 * const)pKey1;
+  const u8 * const p2 = (const u8 * const)pKey2;
+  const u8 * const v1 = &p1[ p1[0] ];   /* Pointer to value 1 */
+  const u8 * const v2 = &p2[ p2[0] ];   /* Pointer to value 2 */
+
+  int n1;
+  int n2;
+  int res;
+
+  getVarint32NR(&p1[1], n1);
+  getVarint32NR(&p2[1], n2);
+  res = memcmp(v1, v2, (MIN(n1, n2) - 13)/2);
+  if( res==0 ){
+    res = n1 - n2;
+  }
+
+  if( res==0 ){
+    if( pTask->pSorter->pKeyInfo->nKeyField>1 ){
+      res = vdbeSorterCompareTail(
+          pTask, pbKey2Cached, pKey1, nKey1, pKey2, nKey2
+      );
+    }
+  }else{
+    assert( !(pTask->pSorter->pKeyInfo->aSortFlags[0]&KEYINFO_ORDER_BIGNULL) );
+    if( pTask->pSorter->pKeyInfo->aSortFlags[0] ){
+      res = res * -1;
+    }
+  }
+
+  return res;
+}
+
+/*
+** A specially optimized version of vdbeSorterCompare() that assumes that
+** the first field of each key is an INTEGER value.
+*/
+static int vdbeSorterCompareInt(
+  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
+  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
+  const void *pKey1, int nKey1,   /* Left side of comparison */
+  const void *pKey2, int nKey2    /* Right side of comparison */
+){
+  const u8 * const p1 = (const u8 * const)pKey1;
+  const u8 * const p2 = (const u8 * const)pKey2;
+  const int s1 = p1[1];                 /* Left hand serial type */
+  const int s2 = p2[1];                 /* Right hand serial type */
+  const u8 * const v1 = &p1[ p1[0] ];   /* Pointer to value 1 */
+  const u8 * const v2 = &p2[ p2[0] ];   /* Pointer to value 2 */
+  int res;                              /* Return value */
+
+  assert( (s1>0 && s1<7) || s1==8 || s1==9 );
+  assert( (s2>0 && s2<7) || s2==8 || s2==9 );
+
+  if( s1==s2 ){
+    /* The two values have the same sign. Compare using memcmp(). */
+    static const u8 aLen[] = {0, 1, 2, 3, 4, 6, 8, 0, 0, 0 };
+    const u8 n = aLen[s1];
+    int i;
+    res = 0;
+    for(i=0; i<n; i++){
+      if( (res = v1[i] - v2[i])!=0 ){
+        if( ((v1[0] ^ v2[0]) & 0x80)!=0 ){
+          res = v1[0] & 0x80 ? -1 : +1;
+        }
+        break;
+      }
+    }
+  }else if( s1>7 && s2>7 ){
+    res = s1 - s2;
+  }else{
+    if( s2>7 ){
+      res = +1;
+    }else if( s1>7 ){
+      res = -1;
+    }else{
+      res = s1 - s2;
+    }
+    assert( res!=0 );
+
+    if( res>0 ){
+      if( *v1 & 0x80 ) res = -1;
+    }else{
+      if( *v2 & 0x80 ) res = +1;
+    }
+  }
+
+  if( res==0 ){
+    if( pTask->pSorter->pKeyInfo->nKeyField>1 ){
+      res = vdbeSorterCompareTail(
+          pTask, pbKey2Cached, pKey1, nKey1, pKey2, nKey2
+      );
+    }
+  }else if( pTask->pSorter->pKeyInfo->aSortFlags[0] ){
+    assert( !(pTask->pSorter->pKeyInfo->aSortFlags[0]&KEYINFO_ORDER_BIGNULL) );
+    res = res * -1;
+  }
+
+  return res;
+}
+
+/*
+** Initialize the temporary index cursor just opened as a sorter cursor.
+**
+** Usually, the sorter module uses the value of (pCsr->pKeyInfo->nKeyField)
+** to determine the number of fields that should be compared from the
+** records being sorted. However, if the value passed as argument nField
+** is non-zero and the sorter is able to guarantee a stable sort, nField
+** is used instead. This is used when sorting records for a CREATE INDEX
+** statement. In this case, keys are always delivered to the sorter in
+** order of the primary key, which happens to be make up the final part
+** of the records being sorted. So if the sort is stable, there is never
+** any reason to compare PK fields and they can be ignored for a small
+** performance boost.
+**
+** The sorter can guarantee a stable sort when running in single-threaded
+** mode, but not in multi-threaded mode.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterInit(
+  sqlite3 *db,                    /* Database connection (for malloc()) */
+  int nField,                     /* Number of key fields in each record */
+  VdbeCursor *pCsr                /* Cursor that holds the new sorter */
+){
+  int pgsz;                       /* Page size of main database */
+  int i;                          /* Used to iterate through aTask[] */
+  VdbeSorter *pSorter;            /* The new sorter */
+  KeyInfo *pKeyInfo;              /* Copy of pCsr->pKeyInfo with db==0 */
+  int szKeyInfo;                  /* Size of pCsr->pKeyInfo in bytes */
+  int sz;                         /* Size of pSorter in bytes */
+  int rc = SQLITE_OK;
+#if SQLITE_MAX_WORKER_THREADS==0
+# define nWorker 0
+#else
+  int nWorker;
+#endif
+
+  /* Initialize the upper limit on the number of worker threads */
+#if SQLITE_MAX_WORKER_THREADS>0
+  if( sqlite3TempInMemory(db) || sqlite3GlobalConfig.bCoreMutex==0 ){
+    nWorker = 0;
+  }else{
+    nWorker = db->aLimit[SQLITE_LIMIT_WORKER_THREADS];
+  }
+#endif
+
+  /* Do not allow the total number of threads (main thread + all workers)
+  ** to exceed the maximum merge count */
+#if SQLITE_MAX_WORKER_THREADS>=SORTER_MAX_MERGE_COUNT
+  if( nWorker>=SORTER_MAX_MERGE_COUNT ){
+    nWorker = SORTER_MAX_MERGE_COUNT-1;
+  }
+#endif
+
+  assert( pCsr->pKeyInfo );
+  assert( !pCsr->isEphemeral );
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  szKeyInfo = sizeof(KeyInfo) + (pCsr->pKeyInfo->nKeyField-1)*sizeof(CollSeq*);
+  sz = sizeof(VdbeSorter) + nWorker * sizeof(SortSubtask);
+
+  pSorter = (VdbeSorter*)sqlite3DbMallocZero(db, sz + szKeyInfo);
+  pCsr->uc.pSorter = pSorter;
+  if( pSorter==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+  }else{
+    Btree *pBt = db->aDb[0].pBt;
+    pSorter->pKeyInfo = pKeyInfo = (KeyInfo*)((u8*)pSorter + sz);
+    memcpy(pKeyInfo, pCsr->pKeyInfo, szKeyInfo);
+    pKeyInfo->db = 0;
+    if( nField && nWorker==0 ){
+      pKeyInfo->nKeyField = nField;
+    }
+    sqlite3BtreeEnter(pBt);
+    pSorter->pgsz = pgsz = sqlite3BtreeGetPageSize(pBt);
+    sqlite3BtreeLeave(pBt);
+    pSorter->nTask = nWorker + 1;
+    pSorter->iPrev = (u8)(nWorker - 1);
+    pSorter->bUseThreads = (pSorter->nTask>1);
+    pSorter->db = db;
+    for(i=0; i<pSorter->nTask; i++){
+      SortSubtask *pTask = &pSorter->aTask[i];
+      pTask->pSorter = pSorter;
+    }
+
+    if( !sqlite3TempInMemory(db) ){
+      i64 mxCache;                /* Cache size in bytes*/
+      u32 szPma = sqlite3GlobalConfig.szPma;
+      pSorter->mnPmaSize = szPma * pgsz;
+
+      mxCache = db->aDb[0].pSchema->cache_size;
+      if( mxCache<0 ){
+        /* A negative cache-size value C indicates that the cache is abs(C)
+        ** KiB in size.  */
+        mxCache = mxCache * -1024;
+      }else{
+        mxCache = mxCache * pgsz;
+      }
+      mxCache = MIN(mxCache, SQLITE_MAX_PMASZ);
+      pSorter->mxPmaSize = MAX(pSorter->mnPmaSize, (int)mxCache);
+
+      /* Avoid large memory allocations if the application has requested
+      ** SQLITE_CONFIG_SMALL_MALLOC. */
+      if( sqlite3GlobalConfig.bSmallMalloc==0 ){
+        assert( pSorter->iMemory==0 );
+        pSorter->nMemory = pgsz;
+        pSorter->list.aMemory = (u8*)sqlite3Malloc(pgsz);
+        if( !pSorter->list.aMemory ) rc = SQLITE_NOMEM_BKPT;
+      }
+    }
+
+    if( pKeyInfo->nAllField<13
+     && (pKeyInfo->aColl[0]==0 || pKeyInfo->aColl[0]==db->pDfltColl)
+     && (pKeyInfo->aSortFlags[0] & KEYINFO_ORDER_BIGNULL)==0
+    ){
+      pSorter->typeMask = SORTER_TYPE_INTEGER | SORTER_TYPE_TEXT;
+    }
+  }
+
+  return rc;
+}
+#undef nWorker   /* Defined at the top of this function */
+
+/*
+** Free the list of sorted records starting at pRecord.
+*/
+static void vdbeSorterRecordFree(sqlite3 *db, SorterRecord *pRecord){
+  SorterRecord *p;
+  SorterRecord *pNext;
+  for(p=pRecord; p; p=pNext){
+    pNext = p->u.pNext;
+    sqlite3DbFree(db, p);
+  }
+}
+
+/*
+** Free all resources owned by the object indicated by argument pTask. All
+** fields of *pTask are zeroed before returning.
+*/
+static void vdbeSortSubtaskCleanup(sqlite3 *db, SortSubtask *pTask){
+  sqlite3DbFree(db, pTask->pUnpacked);
+#if SQLITE_MAX_WORKER_THREADS>0
+  /* pTask->list.aMemory can only be non-zero if it was handed memory
+  ** from the main thread.  That only occurs SQLITE_MAX_WORKER_THREADS>0 */
+  if( pTask->list.aMemory ){
+    sqlite3_free(pTask->list.aMemory);
+  }else
+#endif
+  {
+    assert( pTask->list.aMemory==0 );
+    vdbeSorterRecordFree(0, pTask->list.pList);
+  }
+  if( pTask->file.pFd ){
+    sqlite3OsCloseFree(pTask->file.pFd);
+  }
+  if( pTask->file2.pFd ){
+    sqlite3OsCloseFree(pTask->file2.pFd);
+  }
+  memset(pTask, 0, sizeof(SortSubtask));
+}
+
+#ifdef SQLITE_DEBUG_SORTER_THREADS
+static void vdbeSorterWorkDebug(SortSubtask *pTask, const char *zEvent){
+  i64 t;
+  int iTask = (pTask - pTask->pSorter->aTask);
+  sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t);
+  fprintf(stderr, "%lld:%d %s\n", t, iTask, zEvent);
+}
+static void vdbeSorterRewindDebug(const char *zEvent){
+  i64 t = 0;
+  sqlite3_vfs *pVfs = sqlite3_vfs_find(0);
+  if( ALWAYS(pVfs) ) sqlite3OsCurrentTimeInt64(pVfs, &t);
+  fprintf(stderr, "%lld:X %s\n", t, zEvent);
+}
+static void vdbeSorterPopulateDebug(
+  SortSubtask *pTask,
+  const char *zEvent
+){
+  i64 t;
+  int iTask = (pTask - pTask->pSorter->aTask);
+  sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t);
+  fprintf(stderr, "%lld:bg%d %s\n", t, iTask, zEvent);
+}
+static void vdbeSorterBlockDebug(
+  SortSubtask *pTask,
+  int bBlocked,
+  const char *zEvent
+){
+  if( bBlocked ){
+    i64 t;
+    sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t);
+    fprintf(stderr, "%lld:main %s\n", t, zEvent);
+  }
+}
+#else
+# define vdbeSorterWorkDebug(x,y)
+# define vdbeSorterRewindDebug(y)
+# define vdbeSorterPopulateDebug(x,y)
+# define vdbeSorterBlockDebug(x,y,z)
+#endif
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** Join thread pTask->thread.
+*/
+static int vdbeSorterJoinThread(SortSubtask *pTask){
+  int rc = SQLITE_OK;
+  if( pTask->pThread ){
+#ifdef SQLITE_DEBUG_SORTER_THREADS
+    int bDone = pTask->bDone;
+#endif
+    void *pRet = SQLITE_INT_TO_PTR(SQLITE_ERROR);
+    vdbeSorterBlockDebug(pTask, !bDone, "enter");
+    (void)sqlite3ThreadJoin(pTask->pThread, &pRet);
+    vdbeSorterBlockDebug(pTask, !bDone, "exit");
+    rc = SQLITE_PTR_TO_INT(pRet);
+    assert( pTask->bDone==1 );
+    pTask->bDone = 0;
+    pTask->pThread = 0;
+  }
+  return rc;
+}
+
+/*
+** Launch a background thread to run xTask(pIn).
+*/
+static int vdbeSorterCreateThread(
+  SortSubtask *pTask,             /* Thread will use this task object */
+  void *(*xTask)(void*),          /* Routine to run in a separate thread */
+  void *pIn                       /* Argument passed into xTask() */
+){
+  assert( pTask->pThread==0 && pTask->bDone==0 );
+  return sqlite3ThreadCreate(&pTask->pThread, xTask, pIn);
+}
+
+/*
+** Join all outstanding threads launched by SorterWrite() to create
+** level-0 PMAs.
+*/
+static int vdbeSorterJoinAll(VdbeSorter *pSorter, int rcin){
+  int rc = rcin;
+  int i;
+
+  /* This function is always called by the main user thread.
+  **
+  ** If this function is being called after SorterRewind() has been called,
+  ** it is possible that thread pSorter->aTask[pSorter->nTask-1].pThread
+  ** is currently attempt to join one of the other threads. To avoid a race
+  ** condition where this thread also attempts to join the same object, join
+  ** thread pSorter->aTask[pSorter->nTask-1].pThread first. */
+  for(i=pSorter->nTask-1; i>=0; i--){
+    SortSubtask *pTask = &pSorter->aTask[i];
+    int rc2 = vdbeSorterJoinThread(pTask);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+  return rc;
+}
+#else
+# define vdbeSorterJoinAll(x,rcin) (rcin)
+# define vdbeSorterJoinThread(pTask) SQLITE_OK
+#endif
+
+/*
+** Allocate a new MergeEngine object capable of handling up to
+** nReader PmaReader inputs.
+**
+** nReader is automatically rounded up to the next power of two.
+** nReader may not exceed SORTER_MAX_MERGE_COUNT even after rounding up.
+*/
+static MergeEngine *vdbeMergeEngineNew(int nReader){
+  int N = 2;                      /* Smallest power of two >= nReader */
+  int nByte;                      /* Total bytes of space to allocate */
+  MergeEngine *pNew;              /* Pointer to allocated object to return */
+
+  assert( nReader<=SORTER_MAX_MERGE_COUNT );
+
+  while( N<nReader ) N += N;
+  nByte = sizeof(MergeEngine) + N * (sizeof(int) + sizeof(PmaReader));
+
+  pNew = sqlite3FaultSim(100) ? 0 : (MergeEngine*)sqlite3MallocZero(nByte);
+  if( pNew ){
+    pNew->nTree = N;
+    pNew->pTask = 0;
+    pNew->aReadr = (PmaReader*)&pNew[1];
+    pNew->aTree = (int*)&pNew->aReadr[N];
+  }
+  return pNew;
+}
+
+/*
+** Free the MergeEngine object passed as the only argument.
+*/
+static void vdbeMergeEngineFree(MergeEngine *pMerger){
+  int i;
+  if( pMerger ){
+    for(i=0; i<pMerger->nTree; i++){
+      vdbePmaReaderClear(&pMerger->aReadr[i]);
+    }
+  }
+  sqlite3_free(pMerger);
+}
+
+/*
+** Free all resources associated with the IncrMerger object indicated by
+** the first argument.
+*/
+static void vdbeIncrFree(IncrMerger *pIncr){
+  if( pIncr ){
+#if SQLITE_MAX_WORKER_THREADS>0
+    if( pIncr->bUseThread ){
+      vdbeSorterJoinThread(pIncr->pTask);
+      if( pIncr->aFile[0].pFd ) sqlite3OsCloseFree(pIncr->aFile[0].pFd);
+      if( pIncr->aFile[1].pFd ) sqlite3OsCloseFree(pIncr->aFile[1].pFd);
+    }
+#endif
+    vdbeMergeEngineFree(pIncr->pMerger);
+    sqlite3_free(pIncr);
+  }
+}
+
+/*
+** Reset a sorting cursor back to its original empty state.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSorterReset(sqlite3 *db, VdbeSorter *pSorter){
+  int i;
+  (void)vdbeSorterJoinAll(pSorter, SQLITE_OK);
+  assert( pSorter->bUseThreads || pSorter->pReader==0 );
+#if SQLITE_MAX_WORKER_THREADS>0
+  if( pSorter->pReader ){
+    vdbePmaReaderClear(pSorter->pReader);
+    sqlite3DbFree(db, pSorter->pReader);
+    pSorter->pReader = 0;
+  }
+#endif
+  vdbeMergeEngineFree(pSorter->pMerger);
+  pSorter->pMerger = 0;
+  for(i=0; i<pSorter->nTask; i++){
+    SortSubtask *pTask = &pSorter->aTask[i];
+    vdbeSortSubtaskCleanup(db, pTask);
+    pTask->pSorter = pSorter;
+  }
+  if( pSorter->list.aMemory==0 ){
+    vdbeSorterRecordFree(0, pSorter->list.pList);
+  }
+  pSorter->list.pList = 0;
+  pSorter->list.szPMA = 0;
+  pSorter->bUsePMA = 0;
+  pSorter->iMemory = 0;
+  pSorter->mxKeysize = 0;
+  sqlite3DbFree(db, pSorter->pUnpacked);
+  pSorter->pUnpacked = 0;
+}
+
+/*
+** Free any cursor components allocated by sqlite3VdbeSorterXXX routines.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *db, VdbeCursor *pCsr){
+  VdbeSorter *pSorter;
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  if( pSorter ){
+    sqlite3VdbeSorterReset(db, pSorter);
+    sqlite3_free(pSorter->list.aMemory);
+    sqlite3DbFree(db, pSorter);
+    pCsr->uc.pSorter = 0;
+  }
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/*
+** The first argument is a file-handle open on a temporary file. The file
+** is guaranteed to be nByte bytes or smaller in size. This function
+** attempts to extend the file to nByte bytes in size and to ensure that
+** the VFS has memory mapped it.
+**
+** Whether or not the file does end up memory mapped of course depends on
+** the specific VFS implementation.
+*/
+static void vdbeSorterExtendFile(sqlite3 *db, sqlite3_file *pFd, i64 nByte){
+  if( nByte<=(i64)(db->nMaxSorterMmap) && pFd->pMethods->iVersion>=3 ){
+    void *p = 0;
+    int chunksize = 4*1024;
+    sqlite3OsFileControlHint(pFd, SQLITE_FCNTL_CHUNK_SIZE, &chunksize);
+    sqlite3OsFileControlHint(pFd, SQLITE_FCNTL_SIZE_HINT, &nByte);
+    sqlite3OsFetch(pFd, 0, (int)nByte, &p);
+    if( p ) sqlite3OsUnfetch(pFd, 0, p);
+  }
+}
+#else
+# define vdbeSorterExtendFile(x,y,z)
+#endif
+
+/*
+** Allocate space for a file-handle and open a temporary file. If successful,
+** set *ppFd to point to the malloc'd file-handle and return SQLITE_OK.
+** Otherwise, set *ppFd to 0 and return an SQLite error code.
+*/
+static int vdbeSorterOpenTempFile(
+  sqlite3 *db,                    /* Database handle doing sort */
+  i64 nExtend,                    /* Attempt to extend file to this size */
+  sqlite3_file **ppFd
+){
+  int rc;
+  if( sqlite3FaultSim(202) ) return SQLITE_IOERR_ACCESS;
+  rc = sqlite3OsOpenMalloc(db->pVfs, 0, ppFd,
+      SQLITE_OPEN_TEMP_JOURNAL |
+      SQLITE_OPEN_READWRITE    | SQLITE_OPEN_CREATE |
+      SQLITE_OPEN_EXCLUSIVE    | SQLITE_OPEN_DELETEONCLOSE, &rc
+  );
+  if( rc==SQLITE_OK ){
+    i64 max = SQLITE_MAX_MMAP_SIZE;
+    sqlite3OsFileControlHint(*ppFd, SQLITE_FCNTL_MMAP_SIZE, (void*)&max);
+    if( nExtend>0 ){
+      vdbeSorterExtendFile(db, *ppFd, nExtend);
+    }
+  }
+  return rc;
+}
+
+/*
+** If it has not already been allocated, allocate the UnpackedRecord
+** structure at pTask->pUnpacked. Return SQLITE_OK if successful (or
+** if no allocation was required), or SQLITE_NOMEM otherwise.
+*/
+static int vdbeSortAllocUnpacked(SortSubtask *pTask){
+  if( pTask->pUnpacked==0 ){
+    pTask->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pTask->pSorter->pKeyInfo);
+    if( pTask->pUnpacked==0 ) return SQLITE_NOMEM_BKPT;
+    pTask->pUnpacked->nField = pTask->pSorter->pKeyInfo->nKeyField;
+    pTask->pUnpacked->errCode = 0;
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** Merge the two sorted lists p1 and p2 into a single list.
+*/
+static SorterRecord *vdbeSorterMerge(
+  SortSubtask *pTask,             /* Calling thread context */
+  SorterRecord *p1,               /* First list to merge */
+  SorterRecord *p2                /* Second list to merge */
+){
+  SorterRecord *pFinal = 0;
+  SorterRecord **pp = &pFinal;
+  int bCached = 0;
+
+  assert( p1!=0 && p2!=0 );
+  for(;;){
+    int res;
+    res = pTask->xCompare(
+        pTask, &bCached, SRVAL(p1), p1->nVal, SRVAL(p2), p2->nVal
+    );
+
+    if( res<=0 ){
+      *pp = p1;
+      pp = &p1->u.pNext;
+      p1 = p1->u.pNext;
+      if( p1==0 ){
+        *pp = p2;
+        break;
+      }
+    }else{
+      *pp = p2;
+      pp = &p2->u.pNext;
+      p2 = p2->u.pNext;
+      bCached = 0;
+      if( p2==0 ){
+        *pp = p1;
+        break;
+      }
+    }
+  }
+  return pFinal;
+}
+
+/*
+** Return the SorterCompare function to compare values collected by the
+** sorter object passed as the only argument.
+*/
+static SorterCompare vdbeSorterGetCompare(VdbeSorter *p){
+  if( p->typeMask==SORTER_TYPE_INTEGER ){
+    return vdbeSorterCompareInt;
+  }else if( p->typeMask==SORTER_TYPE_TEXT ){
+    return vdbeSorterCompareText;
+  }
+  return vdbeSorterCompare;
+}
+
+/*
+** Sort the linked list of records headed at pTask->pList. Return
+** SQLITE_OK if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if
+** an error occurs.
+*/
+static int vdbeSorterSort(SortSubtask *pTask, SorterList *pList){
+  int i;
+  SorterRecord *p;
+  int rc;
+  SorterRecord *aSlot[64];
+
+  rc = vdbeSortAllocUnpacked(pTask);
+  if( rc!=SQLITE_OK ) return rc;
+
+  p = pList->pList;
+  pTask->xCompare = vdbeSorterGetCompare(pTask->pSorter);
+  memset(aSlot, 0, sizeof(aSlot));
+
+  while( p ){
+    SorterRecord *pNext;
+    if( pList->aMemory ){
+      if( (u8*)p==pList->aMemory ){
+        pNext = 0;
+      }else{
+        assert( p->u.iNext<sqlite3MallocSize(pList->aMemory) );
+        pNext = (SorterRecord*)&pList->aMemory[p->u.iNext];
+      }
+    }else{
+      pNext = p->u.pNext;
+    }
+
+    p->u.pNext = 0;
+    for(i=0; aSlot[i]; i++){
+      p = vdbeSorterMerge(pTask, p, aSlot[i]);
+      aSlot[i] = 0;
+    }
+    aSlot[i] = p;
+    p = pNext;
+  }
+
+  p = 0;
+  for(i=0; i<ArraySize(aSlot); i++){
+    if( aSlot[i]==0 ) continue;
+    p = p ? vdbeSorterMerge(pTask, p, aSlot[i]) : aSlot[i];
+  }
+  pList->pList = p;
+
+  assert( pTask->pUnpacked->errCode==SQLITE_OK
+       || pTask->pUnpacked->errCode==SQLITE_NOMEM
+  );
+  return pTask->pUnpacked->errCode;
+}
+
+/*
+** Initialize a PMA-writer object.
+*/
+static void vdbePmaWriterInit(
+  sqlite3_file *pFd,              /* File handle to write to */
+  PmaWriter *p,                   /* Object to populate */
+  int nBuf,                       /* Buffer size */
+  i64 iStart                      /* Offset of pFd to begin writing at */
+){
+  memset(p, 0, sizeof(PmaWriter));
+  p->aBuffer = (u8*)sqlite3Malloc(nBuf);
+  if( !p->aBuffer ){
+    p->eFWErr = SQLITE_NOMEM_BKPT;
+  }else{
+    p->iBufEnd = p->iBufStart = (iStart % nBuf);
+    p->iWriteOff = iStart - p->iBufStart;
+    p->nBuffer = nBuf;
+    p->pFd = pFd;
+  }
+}
+
+/*
+** Write nData bytes of data to the PMA. Return SQLITE_OK
+** if successful, or an SQLite error code if an error occurs.
+*/
+static void vdbePmaWriteBlob(PmaWriter *p, u8 *pData, int nData){
+  int nRem = nData;
+  while( nRem>0 && p->eFWErr==0 ){
+    int nCopy = nRem;
+    if( nCopy>(p->nBuffer - p->iBufEnd) ){
+      nCopy = p->nBuffer - p->iBufEnd;
+    }
+
+    memcpy(&p->aBuffer[p->iBufEnd], &pData[nData-nRem], nCopy);
+    p->iBufEnd += nCopy;
+    if( p->iBufEnd==p->nBuffer ){
+      p->eFWErr = sqlite3OsWrite(p->pFd,
+          &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart,
+          p->iWriteOff + p->iBufStart
+      );
+      p->iBufStart = p->iBufEnd = 0;
+      p->iWriteOff += p->nBuffer;
+    }
+    assert( p->iBufEnd<p->nBuffer );
+
+    nRem -= nCopy;
+  }
+}
+
+/*
+** Flush any buffered data to disk and clean up the PMA-writer object.
+** The results of using the PMA-writer after this call are undefined.
+** Return SQLITE_OK if flushing the buffered data succeeds or is not
+** required. Otherwise, return an SQLite error code.
+**
+** Before returning, set *piEof to the offset immediately following the
+** last byte written to the file.
+*/
+static int vdbePmaWriterFinish(PmaWriter *p, i64 *piEof){
+  int rc;
+  if( p->eFWErr==0 && ALWAYS(p->aBuffer) && p->iBufEnd>p->iBufStart ){
+    p->eFWErr = sqlite3OsWrite(p->pFd,
+        &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart,
+        p->iWriteOff + p->iBufStart
+    );
+  }
+  *piEof = (p->iWriteOff + p->iBufEnd);
+  sqlite3_free(p->aBuffer);
+  rc = p->eFWErr;
+  memset(p, 0, sizeof(PmaWriter));
+  return rc;
+}
+
+/*
+** Write value iVal encoded as a varint to the PMA. Return
+** SQLITE_OK if successful, or an SQLite error code if an error occurs.
+*/
+static void vdbePmaWriteVarint(PmaWriter *p, u64 iVal){
+  int nByte;
+  u8 aByte[10];
+  nByte = sqlite3PutVarint(aByte, iVal);
+  vdbePmaWriteBlob(p, aByte, nByte);
+}
+
+/*
+** Write the current contents of in-memory linked-list pList to a level-0
+** PMA in the temp file belonging to sub-task pTask. Return SQLITE_OK if
+** successful, or an SQLite error code otherwise.
+**
+** The format of a PMA is:
+**
+**     * A varint. This varint contains the total number of bytes of content
+**       in the PMA (not including the varint itself).
+**
+**     * One or more records packed end-to-end in order of ascending keys.
+**       Each record consists of a varint followed by a blob of data (the
+**       key). The varint is the number of bytes in the blob of data.
+*/
+static int vdbeSorterListToPMA(SortSubtask *pTask, SorterList *pList){
+  sqlite3 *db = pTask->pSorter->db;
+  int rc = SQLITE_OK;             /* Return code */
+  PmaWriter writer;               /* Object used to write to the file */
+
+#ifdef SQLITE_DEBUG
+  /* Set iSz to the expected size of file pTask->file after writing the PMA.
+  ** This is used by an assert() statement at the end of this function.  */
+  i64 iSz = pList->szPMA + sqlite3VarintLen(pList->szPMA) + pTask->file.iEof;
+#endif
+
+  vdbeSorterWorkDebug(pTask, "enter");
+  memset(&writer, 0, sizeof(PmaWriter));
+  assert( pList->szPMA>0 );
+
+  /* If the first temporary PMA file has not been opened, open it now. */
+  if( pTask->file.pFd==0 ){
+    rc = vdbeSorterOpenTempFile(db, 0, &pTask->file.pFd);
+    assert( rc!=SQLITE_OK || pTask->file.pFd );
+    assert( pTask->file.iEof==0 );
+    assert( pTask->nPMA==0 );
+  }
+
+  /* Try to get the file to memory map */
+  if( rc==SQLITE_OK ){
+    vdbeSorterExtendFile(db, pTask->file.pFd, pTask->file.iEof+pList->szPMA+9);
+  }
+
+  /* Sort the list */
+  if( rc==SQLITE_OK ){
+    rc = vdbeSorterSort(pTask, pList);
+  }
+
+  if( rc==SQLITE_OK ){
+    SorterRecord *p;
+    SorterRecord *pNext = 0;
+
+    vdbePmaWriterInit(pTask->file.pFd, &writer, pTask->pSorter->pgsz,
+                      pTask->file.iEof);
+    pTask->nPMA++;
+    vdbePmaWriteVarint(&writer, pList->szPMA);
+    for(p=pList->pList; p; p=pNext){
+      pNext = p->u.pNext;
+      vdbePmaWriteVarint(&writer, p->nVal);
+      vdbePmaWriteBlob(&writer, SRVAL(p), p->nVal);
+      if( pList->aMemory==0 ) sqlite3_free(p);
+    }
+    pList->pList = p;
+    rc = vdbePmaWriterFinish(&writer, &pTask->file.iEof);
+  }
+
+  vdbeSorterWorkDebug(pTask, "exit");
+  assert( rc!=SQLITE_OK || pList->pList==0 );
+  assert( rc!=SQLITE_OK || pTask->file.iEof==iSz );
+  return rc;
+}
+
+/*
+** Advance the MergeEngine to its next entry.
+** Set *pbEof to true there is no next entry because
+** the MergeEngine has reached the end of all its inputs.
+**
+** Return SQLITE_OK if successful or an error code if an error occurs.
+*/
+static int vdbeMergeEngineStep(
+  MergeEngine *pMerger,      /* The merge engine to advance to the next row */
+  int *pbEof                 /* Set TRUE at EOF.  Set false for more content */
+){
+  int rc;
+  int iPrev = pMerger->aTree[1];/* Index of PmaReader to advance */
+  SortSubtask *pTask = pMerger->pTask;
+
+  /* Advance the current PmaReader */
+  rc = vdbePmaReaderNext(&pMerger->aReadr[iPrev]);
+
+  /* Update contents of aTree[] */
+  if( rc==SQLITE_OK ){
+    int i;                      /* Index of aTree[] to recalculate */
+    PmaReader *pReadr1;         /* First PmaReader to compare */
+    PmaReader *pReadr2;         /* Second PmaReader to compare */
+    int bCached = 0;
+
+    /* Find the first two PmaReaders to compare. The one that was just
+    ** advanced (iPrev) and the one next to it in the array.  */
+    pReadr1 = &pMerger->aReadr[(iPrev & 0xFFFE)];
+    pReadr2 = &pMerger->aReadr[(iPrev | 0x0001)];
+
+    for(i=(pMerger->nTree+iPrev)/2; i>0; i=i/2){
+      /* Compare pReadr1 and pReadr2. Store the result in variable iRes. */
+      int iRes;
+      if( pReadr1->pFd==0 ){
+        iRes = +1;
+      }else if( pReadr2->pFd==0 ){
+        iRes = -1;
+      }else{
+        iRes = pTask->xCompare(pTask, &bCached,
+            pReadr1->aKey, pReadr1->nKey, pReadr2->aKey, pReadr2->nKey
+        );
+      }
+
+      /* If pReadr1 contained the smaller value, set aTree[i] to its index.
+      ** Then set pReadr2 to the next PmaReader to compare to pReadr1. In this
+      ** case there is no cache of pReadr2 in pTask->pUnpacked, so set
+      ** pKey2 to point to the record belonging to pReadr2.
+      **
+      ** Alternatively, if pReadr2 contains the smaller of the two values,
+      ** set aTree[i] to its index and update pReadr1. If vdbeSorterCompare()
+      ** was actually called above, then pTask->pUnpacked now contains
+      ** a value equivalent to pReadr2. So set pKey2 to NULL to prevent
+      ** vdbeSorterCompare() from decoding pReadr2 again.
+      **
+      ** If the two values were equal, then the value from the oldest
+      ** PMA should be considered smaller. The VdbeSorter.aReadr[] array
+      ** is sorted from oldest to newest, so pReadr1 contains older values
+      ** than pReadr2 iff (pReadr1<pReadr2).  */
+      if( iRes<0 || (iRes==0 && pReadr1<pReadr2) ){
+        pMerger->aTree[i] = (int)(pReadr1 - pMerger->aReadr);
+        pReadr2 = &pMerger->aReadr[ pMerger->aTree[i ^ 0x0001] ];
+        bCached = 0;
+      }else{
+        if( pReadr1->pFd ) bCached = 0;
+        pMerger->aTree[i] = (int)(pReadr2 - pMerger->aReadr);
+        pReadr1 = &pMerger->aReadr[ pMerger->aTree[i ^ 0x0001] ];
+      }
+    }
+    *pbEof = (pMerger->aReadr[pMerger->aTree[1]].pFd==0);
+  }
+
+  return (rc==SQLITE_OK ? pTask->pUnpacked->errCode : rc);
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** The main routine for background threads that write level-0 PMAs.
+*/
+static void *vdbeSorterFlushThread(void *pCtx){
+  SortSubtask *pTask = (SortSubtask*)pCtx;
+  int rc;                         /* Return code */
+  assert( pTask->bDone==0 );
+  rc = vdbeSorterListToPMA(pTask, &pTask->list);
+  pTask->bDone = 1;
+  return SQLITE_INT_TO_PTR(rc);
+}
+#endif /* SQLITE_MAX_WORKER_THREADS>0 */
+
+/*
+** Flush the current contents of VdbeSorter.list to a new PMA, possibly
+** using a background thread.
+*/
+static int vdbeSorterFlushPMA(VdbeSorter *pSorter){
+#if SQLITE_MAX_WORKER_THREADS==0
+  pSorter->bUsePMA = 1;
+  return vdbeSorterListToPMA(&pSorter->aTask[0], &pSorter->list);
+#else
+  int rc = SQLITE_OK;
+  int i;
+  SortSubtask *pTask = 0;    /* Thread context used to create new PMA */
+  int nWorker = (pSorter->nTask-1);
+
+  /* Set the flag to indicate that at least one PMA has been written.
+  ** Or will be, anyhow.  */
+  pSorter->bUsePMA = 1;
+
+  /* Select a sub-task to sort and flush the current list of in-memory
+  ** records to disk. If the sorter is running in multi-threaded mode,
+  ** round-robin between the first (pSorter->nTask-1) tasks. Except, if
+  ** the background thread from a sub-tasks previous turn is still running,
+  ** skip it. If the first (pSorter->nTask-1) sub-tasks are all still busy,
+  ** fall back to using the final sub-task. The first (pSorter->nTask-1)
+  ** sub-tasks are preferred as they use background threads - the final
+  ** sub-task uses the main thread. */
+  for(i=0; i<nWorker; i++){
+    int iTest = (pSorter->iPrev + i + 1) % nWorker;
+    pTask = &pSorter->aTask[iTest];
+    if( pTask->bDone ){
+      rc = vdbeSorterJoinThread(pTask);
+    }
+    if( rc!=SQLITE_OK || pTask->pThread==0 ) break;
+  }
+
+  if( rc==SQLITE_OK ){
+    if( i==nWorker ){
+      /* Use the foreground thread for this operation */
+      rc = vdbeSorterListToPMA(&pSorter->aTask[nWorker], &pSorter->list);
+    }else{
+      /* Launch a background thread for this operation */
+      u8 *aMem;
+      void *pCtx;
+
+      assert( pTask!=0 );
+      assert( pTask->pThread==0 && pTask->bDone==0 );
+      assert( pTask->list.pList==0 );
+      assert( pTask->list.aMemory==0 || pSorter->list.aMemory!=0 );
+
+      aMem = pTask->list.aMemory;
+      pCtx = (void*)pTask;
+      pSorter->iPrev = (u8)(pTask - pSorter->aTask);
+      pTask->list = pSorter->list;
+      pSorter->list.pList = 0;
+      pSorter->list.szPMA = 0;
+      if( aMem ){
+        pSorter->list.aMemory = aMem;
+        pSorter->nMemory = sqlite3MallocSize(aMem);
+      }else if( pSorter->list.aMemory ){
+        pSorter->list.aMemory = sqlite3Malloc(pSorter->nMemory);
+        if( !pSorter->list.aMemory ) return SQLITE_NOMEM_BKPT;
+      }
+
+      rc = vdbeSorterCreateThread(pTask, vdbeSorterFlushThread, pCtx);
+    }
+  }
+
+  return rc;
+#endif /* SQLITE_MAX_WORKER_THREADS!=0 */
+}
+
+/*
+** Add a record to the sorter.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterWrite(
+  const VdbeCursor *pCsr,         /* Sorter cursor */
+  Mem *pVal                       /* Memory cell containing record */
+){
+  VdbeSorter *pSorter;
+  int rc = SQLITE_OK;             /* Return Code */
+  SorterRecord *pNew;             /* New list element */
+  int bFlush;                     /* True to flush contents of memory to PMA */
+  i64 nReq;                       /* Bytes of memory required */
+  i64 nPMA;                       /* Bytes of PMA space required */
+  int t;                          /* serial type of first record field */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  getVarint32NR((const u8*)&pVal->z[1], t);
+  if( t>0 && t<10 && t!=7 ){
+    pSorter->typeMask &= SORTER_TYPE_INTEGER;
+  }else if( t>10 && (t & 0x01) ){
+    pSorter->typeMask &= SORTER_TYPE_TEXT;
+  }else{
+    pSorter->typeMask = 0;
+  }
+
+  assert( pSorter );
+
+  /* Figure out whether or not the current contents of memory should be
+  ** flushed to a PMA before continuing. If so, do so.
+  **
+  ** If using the single large allocation mode (pSorter->aMemory!=0), then
+  ** flush the contents of memory to a new PMA if (a) at least one value is
+  ** already in memory and (b) the new value will not fit in memory.
+  **
+  ** Or, if using separate allocations for each record, flush the contents
+  ** of memory to a PMA if either of the following are true:
+  **
+  **   * The total memory allocated for the in-memory list is greater
+  **     than (page-size * cache-size), or
+  **
+  **   * The total memory allocated for the in-memory list is greater
+  **     than (page-size * 10) and sqlite3HeapNearlyFull() returns true.
+  */
+  nReq = pVal->n + sizeof(SorterRecord);
+  nPMA = pVal->n + sqlite3VarintLen(pVal->n);
+  if( pSorter->mxPmaSize ){
+    if( pSorter->list.aMemory ){
+      bFlush = pSorter->iMemory && (pSorter->iMemory+nReq) > pSorter->mxPmaSize;
+    }else{
+      bFlush = (
+          (pSorter->list.szPMA > pSorter->mxPmaSize)
+       || (pSorter->list.szPMA > pSorter->mnPmaSize && sqlite3HeapNearlyFull())
+      );
+    }
+    if( bFlush ){
+      rc = vdbeSorterFlushPMA(pSorter);
+      pSorter->list.szPMA = 0;
+      pSorter->iMemory = 0;
+      assert( rc!=SQLITE_OK || pSorter->list.pList==0 );
+    }
+  }
+
+  pSorter->list.szPMA += nPMA;
+  if( nPMA>pSorter->mxKeysize ){
+    pSorter->mxKeysize = nPMA;
+  }
+
+  if( pSorter->list.aMemory ){
+    int nMin = pSorter->iMemory + nReq;
+
+    if( nMin>pSorter->nMemory ){
+      u8 *aNew;
+      sqlite3_int64 nNew = 2 * (sqlite3_int64)pSorter->nMemory;
+      int iListOff = -1;
+      if( pSorter->list.pList ){
+        iListOff = (u8*)pSorter->list.pList - pSorter->list.aMemory;
+      }
+      while( nNew < nMin ) nNew = nNew*2;
+      if( nNew > pSorter->mxPmaSize ) nNew = pSorter->mxPmaSize;
+      if( nNew < nMin ) nNew = nMin;
+      aNew = sqlite3Realloc(pSorter->list.aMemory, nNew);
+      if( !aNew ) return SQLITE_NOMEM_BKPT;
+      if( iListOff>=0 ){
+        pSorter->list.pList = (SorterRecord*)&aNew[iListOff];
+      }
+      pSorter->list.aMemory = aNew;
+      pSorter->nMemory = nNew;
+    }
+
+    pNew = (SorterRecord*)&pSorter->list.aMemory[pSorter->iMemory];
+    pSorter->iMemory += ROUND8(nReq);
+    if( pSorter->list.pList ){
+      pNew->u.iNext = (int)((u8*)(pSorter->list.pList) - pSorter->list.aMemory);
+    }
+  }else{
+    pNew = (SorterRecord *)sqlite3Malloc(nReq);
+    if( pNew==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    pNew->u.pNext = pSorter->list.pList;
+  }
+
+  memcpy(SRVAL(pNew), pVal->z, pVal->n);
+  pNew->nVal = pVal->n;
+  pSorter->list.pList = pNew;
+
+  return rc;
+}
+
+/*
+** Read keys from pIncr->pMerger and populate pIncr->aFile[1]. The format
+** of the data stored in aFile[1] is the same as that used by regular PMAs,
+** except that the number-of-bytes varint is omitted from the start.
+*/
+static int vdbeIncrPopulate(IncrMerger *pIncr){
+  int rc = SQLITE_OK;
+  int rc2;
+  i64 iStart = pIncr->iStartOff;
+  SorterFile *pOut = &pIncr->aFile[1];
+  SortSubtask *pTask = pIncr->pTask;
+  MergeEngine *pMerger = pIncr->pMerger;
+  PmaWriter writer;
+  assert( pIncr->bEof==0 );
+
+  vdbeSorterPopulateDebug(pTask, "enter");
+
+  vdbePmaWriterInit(pOut->pFd, &writer, pTask->pSorter->pgsz, iStart);
+  while( rc==SQLITE_OK ){
+    int dummy;
+    PmaReader *pReader = &pMerger->aReadr[ pMerger->aTree[1] ];
+    int nKey = pReader->nKey;
+    i64 iEof = writer.iWriteOff + writer.iBufEnd;
+
+    /* Check if the output file is full or if the input has been exhausted.
+    ** In either case exit the loop. */
+    if( pReader->pFd==0 ) break;
+    if( (iEof + nKey + sqlite3VarintLen(nKey))>(iStart + pIncr->mxSz) ) break;
+
+    /* Write the next key to the output. */
+    vdbePmaWriteVarint(&writer, nKey);
+    vdbePmaWriteBlob(&writer, pReader->aKey, nKey);
+    assert( pIncr->pMerger->pTask==pTask );
+    rc = vdbeMergeEngineStep(pIncr->pMerger, &dummy);
+  }
+
+  rc2 = vdbePmaWriterFinish(&writer, &pOut->iEof);
+  if( rc==SQLITE_OK ) rc = rc2;
+  vdbeSorterPopulateDebug(pTask, "exit");
+  return rc;
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** The main routine for background threads that populate aFile[1] of
+** multi-threaded IncrMerger objects.
+*/
+static void *vdbeIncrPopulateThread(void *pCtx){
+  IncrMerger *pIncr = (IncrMerger*)pCtx;
+  void *pRet = SQLITE_INT_TO_PTR( vdbeIncrPopulate(pIncr) );
+  pIncr->pTask->bDone = 1;
+  return pRet;
+}
+
+/*
+** Launch a background thread to populate aFile[1] of pIncr.
+*/
+static int vdbeIncrBgPopulate(IncrMerger *pIncr){
+  void *p = (void*)pIncr;
+  assert( pIncr->bUseThread );
+  return vdbeSorterCreateThread(pIncr->pTask, vdbeIncrPopulateThread, p);
+}
+#endif
+
+/*
+** This function is called when the PmaReader corresponding to pIncr has
+** finished reading the contents of aFile[0]. Its purpose is to "refill"
+** aFile[0] such that the PmaReader should start rereading it from the
+** beginning.
+**
+** For single-threaded objects, this is accomplished by literally reading
+** keys from pIncr->pMerger and repopulating aFile[0].
+**
+** For multi-threaded objects, all that is required is to wait until the
+** background thread is finished (if it is not already) and then swap
+** aFile[0] and aFile[1] in place. If the contents of pMerger have not
+** been exhausted, this function also launches a new background thread
+** to populate the new aFile[1].
+**
+** SQLITE_OK is returned on success, or an SQLite error code otherwise.
+*/
+static int vdbeIncrSwap(IncrMerger *pIncr){
+  int rc = SQLITE_OK;
+
+#if SQLITE_MAX_WORKER_THREADS>0
+  if( pIncr->bUseThread ){
+    rc = vdbeSorterJoinThread(pIncr->pTask);
+
+    if( rc==SQLITE_OK ){
+      SorterFile f0 = pIncr->aFile[0];
+      pIncr->aFile[0] = pIncr->aFile[1];
+      pIncr->aFile[1] = f0;
+    }
+
+    if( rc==SQLITE_OK ){
+      if( pIncr->aFile[0].iEof==pIncr->iStartOff ){
+        pIncr->bEof = 1;
+      }else{
+        rc = vdbeIncrBgPopulate(pIncr);
+      }
+    }
+  }else
+#endif
+  {
+    rc = vdbeIncrPopulate(pIncr);
+    pIncr->aFile[0] = pIncr->aFile[1];
+    if( pIncr->aFile[0].iEof==pIncr->iStartOff ){
+      pIncr->bEof = 1;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Allocate and return a new IncrMerger object to read data from pMerger.
+**
+** If an OOM condition is encountered, return NULL. In this case free the
+** pMerger argument before returning.
+*/
+static int vdbeIncrMergerNew(
+  SortSubtask *pTask,     /* The thread that will be using the new IncrMerger */
+  MergeEngine *pMerger,   /* The MergeEngine that the IncrMerger will control */
+  IncrMerger **ppOut      /* Write the new IncrMerger here */
+){
+  int rc = SQLITE_OK;
+  IncrMerger *pIncr = *ppOut = (IncrMerger*)
+       (sqlite3FaultSim(100) ? 0 : sqlite3MallocZero(sizeof(*pIncr)));
+  if( pIncr ){
+    pIncr->pMerger = pMerger;
+    pIncr->pTask = pTask;
+    pIncr->mxSz = MAX(pTask->pSorter->mxKeysize+9,pTask->pSorter->mxPmaSize/2);
+    pTask->file2.iEof += pIncr->mxSz;
+  }else{
+    vdbeMergeEngineFree(pMerger);
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  assert( *ppOut!=0 || rc!=SQLITE_OK );
+  return rc;
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** Set the "use-threads" flag on object pIncr.
+*/
+static void vdbeIncrMergerSetThreads(IncrMerger *pIncr){
+  pIncr->bUseThread = 1;
+  pIncr->pTask->file2.iEof -= pIncr->mxSz;
+}
+#endif /* SQLITE_MAX_WORKER_THREADS>0 */
+
+
+
+/*
+** Recompute pMerger->aTree[iOut] by comparing the next keys on the
+** two PmaReaders that feed that entry.  Neither of the PmaReaders
+** are advanced.  This routine merely does the comparison.
+*/
+static void vdbeMergeEngineCompare(
+  MergeEngine *pMerger,  /* Merge engine containing PmaReaders to compare */
+  int iOut               /* Store the result in pMerger->aTree[iOut] */
+){
+  int i1;
+  int i2;
+  int iRes;
+  PmaReader *p1;
+  PmaReader *p2;
+
+  assert( iOut<pMerger->nTree && iOut>0 );
+
+  if( iOut>=(pMerger->nTree/2) ){
+    i1 = (iOut - pMerger->nTree/2) * 2;
+    i2 = i1 + 1;
+  }else{
+    i1 = pMerger->aTree[iOut*2];
+    i2 = pMerger->aTree[iOut*2+1];
+  }
+
+  p1 = &pMerger->aReadr[i1];
+  p2 = &pMerger->aReadr[i2];
+
+  if( p1->pFd==0 ){
+    iRes = i2;
+  }else if( p2->pFd==0 ){
+    iRes = i1;
+  }else{
+    SortSubtask *pTask = pMerger->pTask;
+    int bCached = 0;
+    int res;
+    assert( pTask->pUnpacked!=0 );  /* from vdbeSortSubtaskMain() */
+    res = pTask->xCompare(
+        pTask, &bCached, p1->aKey, p1->nKey, p2->aKey, p2->nKey
+    );
+    if( res<=0 ){
+      iRes = i1;
+    }else{
+      iRes = i2;
+    }
+  }
+
+  pMerger->aTree[iOut] = iRes;
+}
+
+/*
+** Allowed values for the eMode parameter to vdbeMergeEngineInit()
+** and vdbePmaReaderIncrMergeInit().
+**
+** Only INCRINIT_NORMAL is valid in single-threaded builds (when
+** SQLITE_MAX_WORKER_THREADS==0).  The other values are only used
+** when there exists one or more separate worker threads.
+*/
+#define INCRINIT_NORMAL 0
+#define INCRINIT_TASK   1
+#define INCRINIT_ROOT   2
+
+/*
+** Forward reference required as the vdbeIncrMergeInit() and
+** vdbePmaReaderIncrInit() routines are called mutually recursively when
+** building a merge tree.
+*/
+static int vdbePmaReaderIncrInit(PmaReader *pReadr, int eMode);
+
+/*
+** Initialize the MergeEngine object passed as the second argument. Once this
+** function returns, the first key of merged data may be read from the
+** MergeEngine object in the usual fashion.
+**
+** If argument eMode is INCRINIT_ROOT, then it is assumed that any IncrMerge
+** objects attached to the PmaReader objects that the merger reads from have
+** already been populated, but that they have not yet populated aFile[0] and
+** set the PmaReader objects up to read from it. In this case all that is
+** required is to call vdbePmaReaderNext() on each PmaReader to point it at
+** its first key.
+**
+** Otherwise, if eMode is any value other than INCRINIT_ROOT, then use
+** vdbePmaReaderIncrMergeInit() to initialize each PmaReader that feeds data
+** to pMerger.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+static int vdbeMergeEngineInit(
+  SortSubtask *pTask,             /* Thread that will run pMerger */
+  MergeEngine *pMerger,           /* MergeEngine to initialize */
+  int eMode                       /* One of the INCRINIT_XXX constants */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* For looping over PmaReader objects */
+  int nTree;                      /* Number of subtrees to merge */
+
+  /* Failure to allocate the merge would have been detected prior to
+  ** invoking this routine */
+  assert( pMerger!=0 );
+
+  /* eMode is always INCRINIT_NORMAL in single-threaded mode */
+  assert( SQLITE_MAX_WORKER_THREADS>0 || eMode==INCRINIT_NORMAL );
+
+  /* Verify that the MergeEngine is assigned to a single thread */
+  assert( pMerger->pTask==0 );
+  pMerger->pTask = pTask;
+
+  nTree = pMerger->nTree;
+  for(i=0; i<nTree; i++){
+    if( SQLITE_MAX_WORKER_THREADS>0 && eMode==INCRINIT_ROOT ){
+      /* PmaReaders should be normally initialized in order, as if they are
+      ** reading from the same temp file this makes for more linear file IO.
+      ** However, in the INCRINIT_ROOT case, if PmaReader aReadr[nTask-1] is
+      ** in use it will block the vdbePmaReaderNext() call while it uses
+      ** the main thread to fill its buffer. So calling PmaReaderNext()
+      ** on this PmaReader before any of the multi-threaded PmaReaders takes
+      ** better advantage of multi-processor hardware. */
+      rc = vdbePmaReaderNext(&pMerger->aReadr[nTree-i-1]);
+    }else{
+      rc = vdbePmaReaderIncrInit(&pMerger->aReadr[i], INCRINIT_NORMAL);
+    }
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  for(i=pMerger->nTree-1; i>0; i--){
+    vdbeMergeEngineCompare(pMerger, i);
+  }
+  return pTask->pUnpacked->errCode;
+}
+
+/*
+** The PmaReader passed as the first argument is guaranteed to be an
+** incremental-reader (pReadr->pIncr!=0). This function serves to open
+** and/or initialize the temp file related fields of the IncrMerge
+** object at (pReadr->pIncr).
+**
+** If argument eMode is set to INCRINIT_NORMAL, then all PmaReaders
+** in the sub-tree headed by pReadr are also initialized. Data is then
+** loaded into the buffers belonging to pReadr and it is set to point to
+** the first key in its range.
+**
+** If argument eMode is set to INCRINIT_TASK, then pReadr is guaranteed
+** to be a multi-threaded PmaReader and this function is being called in a
+** background thread. In this case all PmaReaders in the sub-tree are
+** initialized as for INCRINIT_NORMAL and the aFile[1] buffer belonging to
+** pReadr is populated. However, pReadr itself is not set up to point
+** to its first key. A call to vdbePmaReaderNext() is still required to do
+** that.
+**
+** The reason this function does not call vdbePmaReaderNext() immediately
+** in the INCRINIT_TASK case is that vdbePmaReaderNext() assumes that it has
+** to block on thread (pTask->thread) before accessing aFile[1]. But, since
+** this entire function is being run by thread (pTask->thread), that will
+** lead to the current background thread attempting to join itself.
+**
+** Finally, if argument eMode is set to INCRINIT_ROOT, it may be assumed
+** that pReadr->pIncr is a multi-threaded IncrMerge objects, and that all
+** child-trees have already been initialized using IncrInit(INCRINIT_TASK).
+** In this case vdbePmaReaderNext() is called on all child PmaReaders and
+** the current PmaReader set to point to the first key in its range.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+static int vdbePmaReaderIncrMergeInit(PmaReader *pReadr, int eMode){
+  int rc = SQLITE_OK;
+  IncrMerger *pIncr = pReadr->pIncr;
+  SortSubtask *pTask = pIncr->pTask;
+  sqlite3 *db = pTask->pSorter->db;
+
+  /* eMode is always INCRINIT_NORMAL in single-threaded mode */
+  assert( SQLITE_MAX_WORKER_THREADS>0 || eMode==INCRINIT_NORMAL );
+
+  rc = vdbeMergeEngineInit(pTask, pIncr->pMerger, eMode);
+
+  /* Set up the required files for pIncr. A multi-threaded IncrMerge object
+  ** requires two temp files to itself, whereas a single-threaded object
+  ** only requires a region of pTask->file2. */
+  if( rc==SQLITE_OK ){
+    int mxSz = pIncr->mxSz;
+#if SQLITE_MAX_WORKER_THREADS>0
+    if( pIncr->bUseThread ){
+      rc = vdbeSorterOpenTempFile(db, mxSz, &pIncr->aFile[0].pFd);
+      if( rc==SQLITE_OK ){
+        rc = vdbeSorterOpenTempFile(db, mxSz, &pIncr->aFile[1].pFd);
+      }
+    }else
+#endif
+    /*if( !pIncr->bUseThread )*/{
+      if( pTask->file2.pFd==0 ){
+        assert( pTask->file2.iEof>0 );
+        rc = vdbeSorterOpenTempFile(db, pTask->file2.iEof, &pTask->file2.pFd);
+        pTask->file2.iEof = 0;
+      }
+      if( rc==SQLITE_OK ){
+        pIncr->aFile[1].pFd = pTask->file2.pFd;
+        pIncr->iStartOff = pTask->file2.iEof;
+        pTask->file2.iEof += mxSz;
+      }
+    }
+  }
+
+#if SQLITE_MAX_WORKER_THREADS>0
+  if( rc==SQLITE_OK && pIncr->bUseThread ){
+    /* Use the current thread to populate aFile[1], even though this
+    ** PmaReader is multi-threaded. If this is an INCRINIT_TASK object,
+    ** then this function is already running in background thread
+    ** pIncr->pTask->thread.
+    **
+    ** If this is the INCRINIT_ROOT object, then it is running in the
+    ** main VDBE thread. But that is Ok, as that thread cannot return
+    ** control to the VDBE or proceed with anything useful until the
+    ** first results are ready from this merger object anyway.
+    */
+    assert( eMode==INCRINIT_ROOT || eMode==INCRINIT_TASK );
+    rc = vdbeIncrPopulate(pIncr);
+  }
+#endif
+
+  if( rc==SQLITE_OK && (SQLITE_MAX_WORKER_THREADS==0 || eMode!=INCRINIT_TASK) ){
+    rc = vdbePmaReaderNext(pReadr);
+  }
+
+  return rc;
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** The main routine for vdbePmaReaderIncrMergeInit() operations run in
+** background threads.
+*/
+static void *vdbePmaReaderBgIncrInit(void *pCtx){
+  PmaReader *pReader = (PmaReader*)pCtx;
+  void *pRet = SQLITE_INT_TO_PTR(
+                  vdbePmaReaderIncrMergeInit(pReader,INCRINIT_TASK)
+               );
+  pReader->pIncr->pTask->bDone = 1;
+  return pRet;
+}
+#endif
+
+/*
+** If the PmaReader passed as the first argument is not an incremental-reader
+** (if pReadr->pIncr==0), then this function is a no-op. Otherwise, it invokes
+** the vdbePmaReaderIncrMergeInit() function with the parameters passed to
+** this routine to initialize the incremental merge.
+**
+** If the IncrMerger object is multi-threaded (IncrMerger.bUseThread==1),
+** then a background thread is launched to call vdbePmaReaderIncrMergeInit().
+** Or, if the IncrMerger is single threaded, the same function is called
+** using the current thread.
+*/
+static int vdbePmaReaderIncrInit(PmaReader *pReadr, int eMode){
+  IncrMerger *pIncr = pReadr->pIncr;   /* Incremental merger */
+  int rc = SQLITE_OK;                  /* Return code */
+  if( pIncr ){
+#if SQLITE_MAX_WORKER_THREADS>0
+    assert( pIncr->bUseThread==0 || eMode==INCRINIT_TASK );
+    if( pIncr->bUseThread ){
+      void *pCtx = (void*)pReadr;
+      rc = vdbeSorterCreateThread(pIncr->pTask, vdbePmaReaderBgIncrInit, pCtx);
+    }else
+#endif
+    {
+      rc = vdbePmaReaderIncrMergeInit(pReadr, eMode);
+    }
+  }
+  return rc;
+}
+
+/*
+** Allocate a new MergeEngine object to merge the contents of nPMA level-0
+** PMAs from pTask->file. If no error occurs, set *ppOut to point to
+** the new object and return SQLITE_OK. Or, if an error does occur, set *ppOut
+** to NULL and return an SQLite error code.
+**
+** When this function is called, *piOffset is set to the offset of the
+** first PMA to read from pTask->file. Assuming no error occurs, it is
+** set to the offset immediately following the last byte of the last
+** PMA before returning. If an error does occur, then the final value of
+** *piOffset is undefined.
+*/
+static int vdbeMergeEngineLevel0(
+  SortSubtask *pTask,             /* Sorter task to read from */
+  int nPMA,                       /* Number of PMAs to read */
+  i64 *piOffset,                  /* IN/OUT: Readr offset in pTask->file */
+  MergeEngine **ppOut             /* OUT: New merge-engine */
+){
+  MergeEngine *pNew;              /* Merge engine to return */
+  i64 iOff = *piOffset;
+  int i;
+  int rc = SQLITE_OK;
+
+  *ppOut = pNew = vdbeMergeEngineNew(nPMA);
+  if( pNew==0 ) rc = SQLITE_NOMEM_BKPT;
+
+  for(i=0; i<nPMA && rc==SQLITE_OK; i++){
+    i64 nDummy = 0;
+    PmaReader *pReadr = &pNew->aReadr[i];
+    rc = vdbePmaReaderInit(pTask, &pTask->file, iOff, pReadr, &nDummy);
+    iOff = pReadr->iEof;
+  }
+
+  if( rc!=SQLITE_OK ){
+    vdbeMergeEngineFree(pNew);
+    *ppOut = 0;
+  }
+  *piOffset = iOff;
+  return rc;
+}
+
+/*
+** Return the depth of a tree comprising nPMA PMAs, assuming a fanout of
+** SORTER_MAX_MERGE_COUNT. The returned value does not include leaf nodes.
+**
+** i.e.
+**
+**   nPMA<=16    -> TreeDepth() == 0
+**   nPMA<=256   -> TreeDepth() == 1
+**   nPMA<=65536 -> TreeDepth() == 2
+*/
+static int vdbeSorterTreeDepth(int nPMA){
+  int nDepth = 0;
+  i64 nDiv = SORTER_MAX_MERGE_COUNT;
+  while( nDiv < (i64)nPMA ){
+    nDiv = nDiv * SORTER_MAX_MERGE_COUNT;
+    nDepth++;
+  }
+  return nDepth;
+}
+
+/*
+** pRoot is the root of an incremental merge-tree with depth nDepth (according
+** to vdbeSorterTreeDepth()). pLeaf is the iSeq'th leaf to be added to the
+** tree, counting from zero. This function adds pLeaf to the tree.
+**
+** If successful, SQLITE_OK is returned. If an error occurs, an SQLite error
+** code is returned and pLeaf is freed.
+*/
+static int vdbeSorterAddToTree(
+  SortSubtask *pTask,             /* Task context */
+  int nDepth,                     /* Depth of tree according to TreeDepth() */
+  int iSeq,                       /* Sequence number of leaf within tree */
+  MergeEngine *pRoot,             /* Root of tree */
+  MergeEngine *pLeaf              /* Leaf to add to tree */
+){
+  int rc = SQLITE_OK;
+  int nDiv = 1;
+  int i;
+  MergeEngine *p = pRoot;
+  IncrMerger *pIncr;
+
+  rc = vdbeIncrMergerNew(pTask, pLeaf, &pIncr);
+
+  for(i=1; i<nDepth; i++){
+    nDiv = nDiv * SORTER_MAX_MERGE_COUNT;
+  }
+
+  for(i=1; i<nDepth && rc==SQLITE_OK; i++){
+    int iIter = (iSeq / nDiv) % SORTER_MAX_MERGE_COUNT;
+    PmaReader *pReadr = &p->aReadr[iIter];
+
+    if( pReadr->pIncr==0 ){
+      MergeEngine *pNew = vdbeMergeEngineNew(SORTER_MAX_MERGE_COUNT);
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM_BKPT;
+      }else{
+        rc = vdbeIncrMergerNew(pTask, pNew, &pReadr->pIncr);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      p = pReadr->pIncr->pMerger;
+      nDiv = nDiv / SORTER_MAX_MERGE_COUNT;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    p->aReadr[iSeq % SORTER_MAX_MERGE_COUNT].pIncr = pIncr;
+  }else{
+    vdbeIncrFree(pIncr);
+  }
+  return rc;
+}
+
+/*
+** This function is called as part of a SorterRewind() operation on a sorter
+** that has already written two or more level-0 PMAs to one or more temp
+** files. It builds a tree of MergeEngine/IncrMerger/PmaReader objects that
+** can be used to incrementally merge all PMAs on disk.
+**
+** If successful, SQLITE_OK is returned and *ppOut set to point to the
+** MergeEngine object at the root of the tree before returning. Or, if an
+** error occurs, an SQLite error code is returned and the final value
+** of *ppOut is undefined.
+*/
+static int vdbeSorterMergeTreeBuild(
+  VdbeSorter *pSorter,       /* The VDBE cursor that implements the sort */
+  MergeEngine **ppOut        /* Write the MergeEngine here */
+){
+  MergeEngine *pMain = 0;
+  int rc = SQLITE_OK;
+  int iTask;
+
+#if SQLITE_MAX_WORKER_THREADS>0
+  /* If the sorter uses more than one task, then create the top-level
+  ** MergeEngine here. This MergeEngine will read data from exactly
+  ** one PmaReader per sub-task.  */
+  assert( pSorter->bUseThreads || pSorter->nTask==1 );
+  if( pSorter->nTask>1 ){
+    pMain = vdbeMergeEngineNew(pSorter->nTask);
+    if( pMain==0 ) rc = SQLITE_NOMEM_BKPT;
+  }
+#endif
+
+  for(iTask=0; rc==SQLITE_OK && iTask<pSorter->nTask; iTask++){
+    SortSubtask *pTask = &pSorter->aTask[iTask];
+    assert( pTask->nPMA>0 || SQLITE_MAX_WORKER_THREADS>0 );
+    if( SQLITE_MAX_WORKER_THREADS==0 || pTask->nPMA ){
+      MergeEngine *pRoot = 0;     /* Root node of tree for this task */
+      int nDepth = vdbeSorterTreeDepth(pTask->nPMA);
+      i64 iReadOff = 0;
+
+      if( pTask->nPMA<=SORTER_MAX_MERGE_COUNT ){
+        rc = vdbeMergeEngineLevel0(pTask, pTask->nPMA, &iReadOff, &pRoot);
+      }else{
+        int i;
+        int iSeq = 0;
+        pRoot = vdbeMergeEngineNew(SORTER_MAX_MERGE_COUNT);
+        if( pRoot==0 ) rc = SQLITE_NOMEM_BKPT;
+        for(i=0; i<pTask->nPMA && rc==SQLITE_OK; i += SORTER_MAX_MERGE_COUNT){
+          MergeEngine *pMerger = 0; /* New level-0 PMA merger */
+          int nReader;              /* Number of level-0 PMAs to merge */
+
+          nReader = MIN(pTask->nPMA - i, SORTER_MAX_MERGE_COUNT);
+          rc = vdbeMergeEngineLevel0(pTask, nReader, &iReadOff, &pMerger);
+          if( rc==SQLITE_OK ){
+            rc = vdbeSorterAddToTree(pTask, nDepth, iSeq++, pRoot, pMerger);
+          }
+        }
+      }
+
+      if( rc==SQLITE_OK ){
+#if SQLITE_MAX_WORKER_THREADS>0
+        if( pMain!=0 ){
+          rc = vdbeIncrMergerNew(pTask, pRoot, &pMain->aReadr[iTask].pIncr);
+        }else
+#endif
+        {
+          assert( pMain==0 );
+          pMain = pRoot;
+        }
+      }else{
+        vdbeMergeEngineFree(pRoot);
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    vdbeMergeEngineFree(pMain);
+    pMain = 0;
+  }
+  *ppOut = pMain;
+  return rc;
+}
+
+/*
+** This function is called as part of an sqlite3VdbeSorterRewind() operation
+** on a sorter that has written two or more PMAs to temporary files. It sets
+** up either VdbeSorter.pMerger (for single threaded sorters) or pReader
+** (for multi-threaded sorters) so that it can be used to iterate through
+** all records stored in the sorter.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+static int vdbeSorterSetupMerge(VdbeSorter *pSorter){
+  int rc;                         /* Return code */
+  SortSubtask *pTask0 = &pSorter->aTask[0];
+  MergeEngine *pMain = 0;
+#if SQLITE_MAX_WORKER_THREADS
+  sqlite3 *db = pTask0->pSorter->db;
+  int i;
+  SorterCompare xCompare = vdbeSorterGetCompare(pSorter);
+  for(i=0; i<pSorter->nTask; i++){
+    pSorter->aTask[i].xCompare = xCompare;
+  }
+#endif
+
+  rc = vdbeSorterMergeTreeBuild(pSorter, &pMain);
+  if( rc==SQLITE_OK ){
+#if SQLITE_MAX_WORKER_THREADS
+    assert( pSorter->bUseThreads==0 || pSorter->nTask>1 );
+    if( pSorter->bUseThreads ){
+      int iTask;
+      PmaReader *pReadr = 0;
+      SortSubtask *pLast = &pSorter->aTask[pSorter->nTask-1];
+      rc = vdbeSortAllocUnpacked(pLast);
+      if( rc==SQLITE_OK ){
+        pReadr = (PmaReader*)sqlite3DbMallocZero(db, sizeof(PmaReader));
+        pSorter->pReader = pReadr;
+        if( pReadr==0 ) rc = SQLITE_NOMEM_BKPT;
+      }
+      if( rc==SQLITE_OK ){
+        rc = vdbeIncrMergerNew(pLast, pMain, &pReadr->pIncr);
+        if( rc==SQLITE_OK ){
+          vdbeIncrMergerSetThreads(pReadr->pIncr);
+          for(iTask=0; iTask<(pSorter->nTask-1); iTask++){
+            IncrMerger *pIncr;
+            if( (pIncr = pMain->aReadr[iTask].pIncr) ){
+              vdbeIncrMergerSetThreads(pIncr);
+              assert( pIncr->pTask!=pLast );
+            }
+          }
+          for(iTask=0; rc==SQLITE_OK && iTask<pSorter->nTask; iTask++){
+            /* Check that:
+            **
+            **   a) The incremental merge object is configured to use the
+            **      right task, and
+            **   b) If it is using task (nTask-1), it is configured to run
+            **      in single-threaded mode. This is important, as the
+            **      root merge (INCRINIT_ROOT) will be using the same task
+            **      object.
+            */
+            PmaReader *p = &pMain->aReadr[iTask];
+            assert( p->pIncr==0 || (
+                (p->pIncr->pTask==&pSorter->aTask[iTask])             /* a */
+             && (iTask!=pSorter->nTask-1 || p->pIncr->bUseThread==0)  /* b */
+            ));
+            rc = vdbePmaReaderIncrInit(p, INCRINIT_TASK);
+          }
+        }
+        pMain = 0;
+      }
+      if( rc==SQLITE_OK ){
+        rc = vdbePmaReaderIncrMergeInit(pReadr, INCRINIT_ROOT);
+      }
+    }else
+#endif
+    {
+      rc = vdbeMergeEngineInit(pTask0, pMain, INCRINIT_NORMAL);
+      pSorter->pMerger = pMain;
+      pMain = 0;
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    vdbeMergeEngineFree(pMain);
+  }
+  return rc;
+}
+
+
+/*
+** Once the sorter has been populated by calls to sqlite3VdbeSorterWrite,
+** this function is called to prepare for iterating through the records
+** in sorted order.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterRewind(const VdbeCursor *pCsr, int *pbEof){
+  VdbeSorter *pSorter;
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  assert( pSorter );
+
+  /* If no data has been written to disk, then do not do so now. Instead,
+  ** sort the VdbeSorter.pRecord list. The vdbe layer will read data directly
+  ** from the in-memory list.  */
+  if( pSorter->bUsePMA==0 ){
+    if( pSorter->list.pList ){
+      *pbEof = 0;
+      rc = vdbeSorterSort(&pSorter->aTask[0], &pSorter->list);
+    }else{
+      *pbEof = 1;
+    }
+    return rc;
+  }
+
+  /* Write the current in-memory list to a PMA. When the VdbeSorterWrite()
+  ** function flushes the contents of memory to disk, it immediately always
+  ** creates a new list consisting of a single key immediately afterwards.
+  ** So the list is never empty at this point.  */
+  assert( pSorter->list.pList );
+  rc = vdbeSorterFlushPMA(pSorter);
+
+  /* Join all threads */
+  rc = vdbeSorterJoinAll(pSorter, rc);
+
+  vdbeSorterRewindDebug("rewind");
+
+  /* Assuming no errors have occurred, set up a merger structure to
+  ** incrementally read and merge all remaining PMAs.  */
+  assert( pSorter->pReader==0 );
+  if( rc==SQLITE_OK ){
+    rc = vdbeSorterSetupMerge(pSorter);
+    *pbEof = 0;
+  }
+
+  vdbeSorterRewindDebug("rewinddone");
+  return rc;
+}
+
+/*
+** Advance to the next element in the sorter.  Return value:
+**
+**    SQLITE_OK     success
+**    SQLITE_DONE   end of data
+**    otherwise     some kind of error.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *db, const VdbeCursor *pCsr){
+  VdbeSorter *pSorter;
+  int rc;                         /* Return code */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  assert( pSorter->bUsePMA || (pSorter->pReader==0 && pSorter->pMerger==0) );
+  if( pSorter->bUsePMA ){
+    assert( pSorter->pReader==0 || pSorter->pMerger==0 );
+    assert( pSorter->bUseThreads==0 || pSorter->pReader );
+    assert( pSorter->bUseThreads==1 || pSorter->pMerger );
+#if SQLITE_MAX_WORKER_THREADS>0
+    if( pSorter->bUseThreads ){
+      rc = vdbePmaReaderNext(pSorter->pReader);
+      if( rc==SQLITE_OK && pSorter->pReader->pFd==0 ) rc = SQLITE_DONE;
+    }else
+#endif
+    /*if( !pSorter->bUseThreads )*/ {
+      int res = 0;
+      assert( pSorter->pMerger!=0 );
+      assert( pSorter->pMerger->pTask==(&pSorter->aTask[0]) );
+      rc = vdbeMergeEngineStep(pSorter->pMerger, &res);
+      if( rc==SQLITE_OK && res ) rc = SQLITE_DONE;
+    }
+  }else{
+    SorterRecord *pFree = pSorter->list.pList;
+    pSorter->list.pList = pFree->u.pNext;
+    pFree->u.pNext = 0;
+    if( pSorter->list.aMemory==0 ) vdbeSorterRecordFree(db, pFree);
+    rc = pSorter->list.pList ? SQLITE_OK : SQLITE_DONE;
+  }
+  return rc;
+}
+
+/*
+** Return a pointer to a buffer owned by the sorter that contains the
+** current key.
+*/
+static void *vdbeSorterRowkey(
+  const VdbeSorter *pSorter,      /* Sorter object */
+  int *pnKey                      /* OUT: Size of current key in bytes */
+){
+  void *pKey;
+  if( pSorter->bUsePMA ){
+    PmaReader *pReader;
+#if SQLITE_MAX_WORKER_THREADS>0
+    if( pSorter->bUseThreads ){
+      pReader = pSorter->pReader;
+    }else
+#endif
+    /*if( !pSorter->bUseThreads )*/{
+      pReader = &pSorter->pMerger->aReadr[pSorter->pMerger->aTree[1]];
+    }
+    *pnKey = pReader->nKey;
+    pKey = pReader->aKey;
+  }else{
+    *pnKey = pSorter->list.pList->nVal;
+    pKey = SRVAL(pSorter->list.pList);
+  }
+  return pKey;
+}
+
+/*
+** Copy the current sorter key into the memory cell pOut.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(const VdbeCursor *pCsr, Mem *pOut){
+  VdbeSorter *pSorter;
+  void *pKey; int nKey;           /* Sorter key to copy into pOut */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  pKey = vdbeSorterRowkey(pSorter, &nKey);
+  if( sqlite3VdbeMemClearAndResize(pOut, nKey) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  pOut->n = nKey;
+  MemSetTypeFlag(pOut, MEM_Blob);
+  memcpy(pOut->z, pKey, nKey);
+
+  return SQLITE_OK;
+}
+
+/*
+** Compare the key in memory cell pVal with the key that the sorter cursor
+** passed as the first argument currently points to. For the purposes of
+** the comparison, ignore the rowid field at the end of each record.
+**
+** If the sorter cursor key contains any NULL values, consider it to be
+** less than pVal. Even if pVal also contains NULL values.
+**
+** If an error occurs, return an SQLite error code (i.e. SQLITE_NOMEM).
+** Otherwise, set *pRes to a negative, zero or positive value if the
+** key in pVal is smaller than, equal to or larger than the current sorter
+** key.
+**
+** This routine forms the core of the OP_SorterCompare opcode, which in
+** turn is used to verify uniqueness when constructing a UNIQUE INDEX.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterCompare(
+  const VdbeCursor *pCsr,         /* Sorter cursor */
+  Mem *pVal,                      /* Value to compare to current sorter key */
+  int nKeyCol,                    /* Compare this many columns */
+  int *pRes                       /* OUT: Result of comparison */
+){
+  VdbeSorter *pSorter;
+  UnpackedRecord *r2;
+  KeyInfo *pKeyInfo;
+  int i;
+  void *pKey; int nKey;           /* Sorter key to compare pVal with */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  r2 = pSorter->pUnpacked;
+  pKeyInfo = pCsr->pKeyInfo;
+  if( r2==0 ){
+    r2 = pSorter->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
+    if( r2==0 ) return SQLITE_NOMEM_BKPT;
+    r2->nField = nKeyCol;
+  }
+  assert( r2->nField==nKeyCol );
+
+  pKey = vdbeSorterRowkey(pSorter, &nKey);
+  sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, r2);
+  for(i=0; i<nKeyCol; i++){
+    if( r2->aMem[i].flags & MEM_Null ){
+      *pRes = -1;
+      return SQLITE_OK;
+    }
+  }
+
+  *pRes = sqlite3VdbeRecordCompare(pVal->n, pVal->z, r2);
+  return SQLITE_OK;
+}
+
+/************** End of vdbesort.c ********************************************/
+/************** Begin file vdbevtab.c ****************************************/
+/*
+** 2020-03-23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements virtual-tables for examining the bytecode content
+** of a prepared statement.
+*/
+/* #include "sqliteInt.h" */
+#if defined(SQLITE_ENABLE_BYTECODE_VTAB) && !defined(SQLITE_OMIT_VIRTUALTABLE)
+/* #include "vdbeInt.h" */
+
+/* An instance of the bytecode() table-valued function.
+*/
+typedef struct bytecodevtab bytecodevtab;
+struct bytecodevtab {
+  sqlite3_vtab base;     /* Base class - must be first */
+  sqlite3 *db;           /* Database connection */
+  int bTablesUsed;       /* 2 for tables_used().  0 for bytecode(). */
+};
+
+/* A cursor for scanning through the bytecode
+*/
+typedef struct bytecodevtab_cursor bytecodevtab_cursor;
+struct bytecodevtab_cursor {
+  sqlite3_vtab_cursor base;  /* Base class - must be first */
+  sqlite3_stmt *pStmt;       /* The statement whose bytecode is displayed */
+  int iRowid;                /* The rowid of the output table */
+  int iAddr;                 /* Address */
+  int needFinalize;          /* Cursors owns pStmt and must finalize it */
+  int showSubprograms;       /* Provide a listing of subprograms */
+  Op *aOp;                   /* Operand array */
+  char *zP4;                 /* Rendered P4 value */
+  const char *zType;         /* tables_used.type */
+  const char *zSchema;       /* tables_used.schema */
+  const char *zName;         /* tables_used.name */
+  Mem sub;                   /* Subprograms */
+};
+
+/*
+** Create a new bytecode() table-valued function.
+*/
+static int bytecodevtabConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  bytecodevtab *pNew;
+  int rc;
+  int isTabUsed = pAux!=0;
+  const char *azSchema[2] = {
+    /* bytecode() schema */
+    "CREATE TABLE x("
+      "addr INT,"
+      "opcode TEXT,"
+      "p1 INT,"
+      "p2 INT,"
+      "p3 INT,"
+      "p4 TEXT,"
+      "p5 INT,"
+      "comment TEXT,"
+      "subprog TEXT,"
+      "nexec INT,"
+      "ncycle INT,"
+      "stmt HIDDEN"
+    ");",
+
+    /* Tables_used() schema */
+    "CREATE TABLE x("
+      "type TEXT,"
+      "schema TEXT,"
+      "name TEXT,"
+      "wr INT,"
+      "subprog TEXT,"
+      "stmt HIDDEN"
+   ");"
+  };
+
+  (void)argc;
+  (void)argv;
+  (void)pzErr;
+  rc = sqlite3_declare_vtab(db, azSchema[isTabUsed]);
+  if( rc==SQLITE_OK ){
+    pNew = sqlite3_malloc( sizeof(*pNew) );
+    *ppVtab = (sqlite3_vtab*)pNew;
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, sizeof(*pNew));
+    pNew->db = db;
+    pNew->bTablesUsed = isTabUsed*2;
+  }
+  return rc;
+}
+
+/*
+** This method is the destructor for bytecodevtab objects.
+*/
+static int bytecodevtabDisconnect(sqlite3_vtab *pVtab){
+  bytecodevtab *p = (bytecodevtab*)pVtab;
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Constructor for a new bytecodevtab_cursor object.
+*/
+static int bytecodevtabOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+  bytecodevtab *pVTab = (bytecodevtab*)p;
+  bytecodevtab_cursor *pCur;
+  pCur = sqlite3_malloc( sizeof(*pCur) );
+  if( pCur==0 ) return SQLITE_NOMEM;
+  memset(pCur, 0, sizeof(*pCur));
+  sqlite3VdbeMemInit(&pCur->sub, pVTab->db, 1);
+  *ppCursor = &pCur->base;
+  return SQLITE_OK;
+}
+
+/*
+** Clear all internal content from a bytecodevtab cursor.
+*/
+static void bytecodevtabCursorClear(bytecodevtab_cursor *pCur){
+  sqlite3_free(pCur->zP4);
+  pCur->zP4 = 0;
+  sqlite3VdbeMemRelease(&pCur->sub);
+  sqlite3VdbeMemSetNull(&pCur->sub);
+  if( pCur->needFinalize ){
+    sqlite3_finalize(pCur->pStmt);
+  }
+  pCur->pStmt = 0;
+  pCur->needFinalize = 0;
+  pCur->zType = 0;
+  pCur->zSchema = 0;
+  pCur->zName = 0;
+}
+
+/*
+** Destructor for a bytecodevtab_cursor.
+*/
+static int bytecodevtabClose(sqlite3_vtab_cursor *cur){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  bytecodevtabCursorClear(pCur);
+  sqlite3_free(pCur);
+  return SQLITE_OK;
+}
+
+
+/*
+** Advance a bytecodevtab_cursor to its next row of output.
+*/
+static int bytecodevtabNext(sqlite3_vtab_cursor *cur){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  bytecodevtab *pTab = (bytecodevtab*)cur->pVtab;
+  int rc;
+  if( pCur->zP4 ){
+    sqlite3_free(pCur->zP4);
+    pCur->zP4 = 0;
+  }
+  if( pCur->zName ){
+    pCur->zName = 0;
+    pCur->zType = 0;
+    pCur->zSchema = 0;
+  }
+  rc = sqlite3VdbeNextOpcode(
+           (Vdbe*)pCur->pStmt,
+           pCur->showSubprograms ? &pCur->sub : 0,
+           pTab->bTablesUsed,
+           &pCur->iRowid,
+           &pCur->iAddr,
+           &pCur->aOp);
+  if( rc!=SQLITE_OK ){
+    sqlite3VdbeMemSetNull(&pCur->sub);
+    pCur->aOp = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the cursor has been moved off of the last
+** row of output.
+*/
+static int bytecodevtabEof(sqlite3_vtab_cursor *cur){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  return pCur->aOp==0;
+}
+
+/*
+** Return values of columns for the row at which the bytecodevtab_cursor
+** is currently pointing.
+*/
+static int bytecodevtabColumn(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int i                       /* Which column to return */
+){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  bytecodevtab *pVTab = (bytecodevtab*)cur->pVtab;
+  Op *pOp = pCur->aOp + pCur->iAddr;
+  if( pVTab->bTablesUsed ){
+    if( i==4 ){
+      i = 8;
+    }else{
+      if( i<=2 && pCur->zType==0 ){
+        Schema *pSchema;
+        HashElem *k;
+        int iDb = pOp->p3;
+        Pgno iRoot = (Pgno)pOp->p2;
+        sqlite3 *db = pVTab->db;
+        pSchema = db->aDb[iDb].pSchema;
+        pCur->zSchema = db->aDb[iDb].zDbSName;
+        for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
+          Table *pTab = (Table*)sqliteHashData(k);
+          if( !IsVirtual(pTab) && pTab->tnum==iRoot ){
+            pCur->zName = pTab->zName;
+            pCur->zType = "table";
+            break;
+          }
+        }
+        if( pCur->zName==0 ){
+          for(k=sqliteHashFirst(&pSchema->idxHash); k; k=sqliteHashNext(k)){
+            Index *pIdx = (Index*)sqliteHashData(k);
+            if( pIdx->tnum==iRoot ){
+              pCur->zName = pIdx->zName;
+              pCur->zType = "index";
+            }
+          }
+        }
+      }
+      i += 20;
+    }
+  }
+  switch( i ){
+    case 0:   /* addr */
+      sqlite3_result_int(ctx, pCur->iAddr);
+      break;
+    case 1:   /* opcode */
+      sqlite3_result_text(ctx, (char*)sqlite3OpcodeName(pOp->opcode),
+                          -1, SQLITE_STATIC);
+      break;
+    case 2:   /* p1 */
+      sqlite3_result_int(ctx, pOp->p1);
+      break;
+    case 3:   /* p2 */
+      sqlite3_result_int(ctx, pOp->p2);
+      break;
+    case 4:   /* p3 */
+      sqlite3_result_int(ctx, pOp->p3);
+      break;
+    case 5:   /* p4 */
+    case 7:   /* comment */
+      if( pCur->zP4==0 ){
+        pCur->zP4 = sqlite3VdbeDisplayP4(pVTab->db, pOp);
+      }
+      if( i==5 ){
+        sqlite3_result_text(ctx, pCur->zP4, -1, SQLITE_STATIC);
+      }else{
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+        char *zCom = sqlite3VdbeDisplayComment(pVTab->db, pOp, pCur->zP4);
+        sqlite3_result_text(ctx, zCom, -1, sqlite3_free);
+#endif
+      }
+      break;
+    case 6:     /* p5 */
+      sqlite3_result_int(ctx, pOp->p5);
+      break;
+    case 8: {   /* subprog */
+      Op *aOp = pCur->aOp;
+      assert( aOp[0].opcode==OP_Init );
+      assert( aOp[0].p4.z==0 || strncmp(aOp[0].p4.z,"-" "- ",3)==0 );
+      if( pCur->iRowid==pCur->iAddr+1 ){
+        break;  /* Result is NULL for the main program */
+      }else if( aOp[0].p4.z!=0 ){
+         sqlite3_result_text(ctx, aOp[0].p4.z+3, -1, SQLITE_STATIC);
+      }else{
+         sqlite3_result_text(ctx, "(FK)", 4, SQLITE_STATIC);
+      }
+      break;
+    }
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+    case 9:     /* nexec */
+      sqlite3_result_int64(ctx, pOp->nExec);
+      break;
+    case 10:    /* ncycle */
+      sqlite3_result_int64(ctx, pOp->nCycle);
+      break;
+#else
+    case 9:     /* nexec */
+    case 10:    /* ncycle */
+      sqlite3_result_int(ctx, 0);
+      break;
+#endif
+
+    case 20:  /* tables_used.type */
+      sqlite3_result_text(ctx, pCur->zType, -1, SQLITE_STATIC);
+      break;
+    case 21:  /* tables_used.schema */
+      sqlite3_result_text(ctx, pCur->zSchema, -1, SQLITE_STATIC);
+      break;
+    case 22:  /* tables_used.name */
+      sqlite3_result_text(ctx, pCur->zName, -1, SQLITE_STATIC);
+      break;
+    case 23:  /* tables_used.wr */
+      sqlite3_result_int(ctx, pOp->opcode==OP_OpenWrite);
+      break;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return the rowid for the current row.  In this implementation, the
+** rowid is the same as the output value.
+*/
+static int bytecodevtabRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  *pRowid = pCur->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Initialize a cursor.
+**
+**    idxNum==0     means show all subprograms
+**    idxNum==1     means show only the main bytecode and omit subprograms.
+*/
+static int bytecodevtabFilter(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor *)pVtabCursor;
+  bytecodevtab *pVTab = (bytecodevtab *)pVtabCursor->pVtab;
+  int rc = SQLITE_OK;
+  (void)idxStr;
+
+  bytecodevtabCursorClear(pCur);
+  pCur->iRowid = 0;
+  pCur->iAddr = 0;
+  pCur->showSubprograms = idxNum==0;
+  assert( argc==1 );
+  if( sqlite3_value_type(argv[0])==SQLITE_TEXT ){
+    const char *zSql = (const char*)sqlite3_value_text(argv[0]);
+    if( zSql==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(pVTab->db, zSql, -1, &pCur->pStmt, 0);
+      pCur->needFinalize = 1;
+    }
+  }else{
+    pCur->pStmt = (sqlite3_stmt*)sqlite3_value_pointer(argv[0],"stmt-pointer");
+  }
+  if( pCur->pStmt==0 ){
+    pVTab->base.zErrMsg = sqlite3_mprintf(
+       "argument to %s() is not a valid SQL statement",
+       pVTab->bTablesUsed ? "tables_used" : "bytecode"
+    );
+    rc = SQLITE_ERROR;
+  }else{
+    bytecodevtabNext(pVtabCursor);
+  }
+  return rc;
+}
+
+/*
+** We must have a single stmt=? constraint that will be passed through
+** into the xFilter method.  If there is no valid stmt=? constraint,
+** then return an SQLITE_CONSTRAINT error.
+*/
+static int bytecodevtabBestIndex(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  int i;
+  int rc = SQLITE_CONSTRAINT;
+  struct sqlite3_index_constraint *p;
+  bytecodevtab *pVTab = (bytecodevtab*)tab;
+  int iBaseCol = pVTab->bTablesUsed ? 4 : 10;
+  pIdxInfo->estimatedCost = (double)100;
+  pIdxInfo->estimatedRows = 100;
+  pIdxInfo->idxNum = 0;
+  for(i=0, p=pIdxInfo->aConstraint; i<pIdxInfo->nConstraint; i++, p++){
+    if( p->usable==0 ) continue;
+    if( p->op==SQLITE_INDEX_CONSTRAINT_EQ && p->iColumn==iBaseCol+1 ){
+      rc = SQLITE_OK;
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
+    }
+    if( p->op==SQLITE_INDEX_CONSTRAINT_ISNULL && p->iColumn==iBaseCol ){
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      pIdxInfo->idxNum = 1;
+    }
+  }
+  return rc;
+}
+
+/*
+** This following structure defines all the methods for the
+** virtual table.
+*/
+static sqlite3_module bytecodevtabModule = {
+  /* iVersion    */ 0,
+  /* xCreate     */ 0,
+  /* xConnect    */ bytecodevtabConnect,
+  /* xBestIndex  */ bytecodevtabBestIndex,
+  /* xDisconnect */ bytecodevtabDisconnect,
+  /* xDestroy    */ 0,
+  /* xOpen       */ bytecodevtabOpen,
+  /* xClose      */ bytecodevtabClose,
+  /* xFilter     */ bytecodevtabFilter,
+  /* xNext       */ bytecodevtabNext,
+  /* xEof        */ bytecodevtabEof,
+  /* xColumn     */ bytecodevtabColumn,
+  /* xRowid      */ bytecodevtabRowid,
+  /* xUpdate     */ 0,
+  /* xBegin      */ 0,
+  /* xSync       */ 0,
+  /* xCommit     */ 0,
+  /* xRollback   */ 0,
+  /* xFindMethod */ 0,
+  /* xRename     */ 0,
+  /* xSavepoint  */ 0,
+  /* xRelease    */ 0,
+  /* xRollbackTo */ 0,
+  /* xShadowName */ 0,
+  /* xIntegrity  */ 0
+};
+
+
+SQLITE_PRIVATE int sqlite3VdbeBytecodeVtabInit(sqlite3 *db){
+  int rc;
+  rc = sqlite3_create_module(db, "bytecode", &bytecodevtabModule, 0);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_module(db, "tables_used", &bytecodevtabModule, &db);
+  }
+  return rc;
+}
+#elif defined(SQLITE_ENABLE_BYTECODE_VTAB)
+SQLITE_PRIVATE int sqlite3VdbeBytecodeVtabInit(sqlite3 *db){ return SQLITE_OK; }
+#endif /* SQLITE_ENABLE_BYTECODE_VTAB */
+
+/************** End of vdbevtab.c ********************************************/
+/************** Begin file memjournal.c **************************************/
+/*
+** 2008 October 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code use to implement an in-memory rollback journal.
+** The in-memory rollback journal is used to journal transactions for
+** ":memory:" databases and when the journal_mode=MEMORY pragma is used.
+**
+** Update:  The in-memory journal is also used to temporarily cache
+** smaller journals that are not critical for power-loss recovery.
+** For example, statement journals that are not too big will be held
+** entirely in memory, thus reducing the number of file I/O calls, and
+** more importantly, reducing temporary file creation events.  If these
+** journals become too large for memory, they are spilled to disk.  But
+** in the common case, they are usually small and no file I/O needs to
+** occur.
+*/
+/* #include "sqliteInt.h" */
+
+/* Forward references to internal structures */
+typedef struct MemJournal MemJournal;
+typedef struct FilePoint FilePoint;
+typedef struct FileChunk FileChunk;
+
+/*
+** The rollback journal is composed of a linked list of these structures.
+**
+** The zChunk array is always at least 8 bytes in size - usually much more.
+** Its actual size is stored in the MemJournal.nChunkSize variable.
+*/
+struct FileChunk {
+  FileChunk *pNext;               /* Next chunk in the journal */
+  u8 zChunk[8];                   /* Content of this chunk */
+};
+
+/*
+** By default, allocate this many bytes of memory for each FileChunk object.
+*/
+#define MEMJOURNAL_DFLT_FILECHUNKSIZE 1024
+
+/*
+** For chunk size nChunkSize, return the number of bytes that should
+** be allocated for each FileChunk structure.
+*/
+#define fileChunkSize(nChunkSize) (sizeof(FileChunk) + ((nChunkSize)-8))
+
+/*
+** An instance of this object serves as a cursor into the rollback journal.
+** The cursor can be either for reading or writing.
+*/
+struct FilePoint {
+  sqlite3_int64 iOffset;          /* Offset from the beginning of the file */
+  FileChunk *pChunk;              /* Specific chunk into which cursor points */
+};
+
+/*
+** This structure is a subclass of sqlite3_file. Each open memory-journal
+** is an instance of this class.
+*/
+struct MemJournal {
+  const sqlite3_io_methods *pMethod; /* Parent class. MUST BE FIRST */
+  int nChunkSize;                 /* In-memory chunk-size */
+
+  int nSpill;                     /* Bytes of data before flushing */
+  FileChunk *pFirst;              /* Head of in-memory chunk-list */
+  FilePoint endpoint;             /* Pointer to the end of the file */
+  FilePoint readpoint;            /* Pointer to the end of the last xRead() */
+
+  int flags;                      /* xOpen flags */
+  sqlite3_vfs *pVfs;              /* The "real" underlying VFS */
+  const char *zJournal;           /* Name of the journal file */
+};
+
+/*
+** Read data from the in-memory journal file.  This is the implementation
+** of the sqlite3_vfs.xRead method.
+*/
+static int memjrnlRead(
+  sqlite3_file *pJfd,    /* The journal file from which to read */
+  void *zBuf,            /* Put the results here */
+  int iAmt,              /* Number of bytes to read */
+  sqlite_int64 iOfst     /* Begin reading at this offset */
+){
+  MemJournal *p = (MemJournal *)pJfd;
+  u8 *zOut = zBuf;
+  int nRead = iAmt;
+  int iChunkOffset;
+  FileChunk *pChunk;
+
+  if( (iAmt+iOfst)>p->endpoint.iOffset ){
+    return SQLITE_IOERR_SHORT_READ;
+  }
+  assert( p->readpoint.iOffset==0 || p->readpoint.pChunk!=0 );
+  if( p->readpoint.iOffset!=iOfst || iOfst==0 ){
+    sqlite3_int64 iOff = 0;
+    for(pChunk=p->pFirst;
+        ALWAYS(pChunk) && (iOff+p->nChunkSize)<=iOfst;
+        pChunk=pChunk->pNext
+    ){
+      iOff += p->nChunkSize;
+    }
+  }else{
+    pChunk = p->readpoint.pChunk;
+    assert( pChunk!=0 );
+  }
+
+  iChunkOffset = (int)(iOfst%p->nChunkSize);
+  do {
+    int iSpace = p->nChunkSize - iChunkOffset;
+    int nCopy = MIN(nRead, (p->nChunkSize - iChunkOffset));
+    memcpy(zOut, (u8*)pChunk->zChunk + iChunkOffset, nCopy);
+    zOut += nCopy;
+    nRead -= iSpace;
+    iChunkOffset = 0;
+  } while( nRead>=0 && (pChunk=pChunk->pNext)!=0 && nRead>0 );
+  p->readpoint.iOffset = pChunk ? iOfst+iAmt : 0;
+  p->readpoint.pChunk = pChunk;
+
+  return SQLITE_OK;
+}
+
+/*
+** Free the list of FileChunk structures headed at MemJournal.pFirst.
+*/
+static void memjrnlFreeChunks(FileChunk *pFirst){
+  FileChunk *pIter;
+  FileChunk *pNext;
+  for(pIter=pFirst; pIter; pIter=pNext){
+    pNext = pIter->pNext;
+    sqlite3_free(pIter);
+  }
+}
+
+/*
+** Flush the contents of memory to a real file on disk.
+*/
+static int memjrnlCreateFile(MemJournal *p){
+  int rc;
+  sqlite3_file *pReal = (sqlite3_file*)p;
+  MemJournal copy = *p;
+
+  memset(p, 0, sizeof(MemJournal));
+  rc = sqlite3OsOpen(copy.pVfs, copy.zJournal, pReal, copy.flags, 0);
+  if( rc==SQLITE_OK ){
+    int nChunk = copy.nChunkSize;
+    i64 iOff = 0;
+    FileChunk *pIter;
+    for(pIter=copy.pFirst; pIter; pIter=pIter->pNext){
+      if( iOff + nChunk > copy.endpoint.iOffset ){
+        nChunk = copy.endpoint.iOffset - iOff;
+      }
+      rc = sqlite3OsWrite(pReal, (u8*)pIter->zChunk, nChunk, iOff);
+      if( rc ) break;
+      iOff += nChunk;
+    }
+    if( rc==SQLITE_OK ){
+      /* No error has occurred. Free the in-memory buffers. */
+      memjrnlFreeChunks(copy.pFirst);
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    /* If an error occurred while creating or writing to the file, restore
+    ** the original before returning. This way, SQLite uses the in-memory
+    ** journal data to roll back changes made to the internal page-cache
+    ** before this function was called.  */
+    sqlite3OsClose(pReal);
+    *p = copy;
+  }
+  return rc;
+}
+
+
+/* Forward reference */
+static int memjrnlTruncate(sqlite3_file *pJfd, sqlite_int64 size);
+
+/*
+** Write data to the file.
+*/
+static int memjrnlWrite(
+  sqlite3_file *pJfd,    /* The journal file into which to write */
+  const void *zBuf,      /* Take data to be written from here */
+  int iAmt,              /* Number of bytes to write */
+  sqlite_int64 iOfst     /* Begin writing at this offset into the file */
+){
+  MemJournal *p = (MemJournal *)pJfd;
+  int nWrite = iAmt;
+  u8 *zWrite = (u8 *)zBuf;
+
+  /* If the file should be created now, create it and write the new data
+  ** into the file on disk. */
+  if( p->nSpill>0 && (iAmt+iOfst)>p->nSpill ){
+    int rc = memjrnlCreateFile(p);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3OsWrite(pJfd, zBuf, iAmt, iOfst);
+    }
+    return rc;
+  }
+
+  /* If the contents of this write should be stored in memory */
+  else{
+    /* An in-memory journal file should only ever be appended to. Random
+    ** access writes are not required. The only exception to this is when
+    ** the in-memory journal is being used by a connection using the
+    ** atomic-write optimization. In this case the first 28 bytes of the
+    ** journal file may be written as part of committing the transaction. */
+    assert( iOfst<=p->endpoint.iOffset );
+    if( iOfst>0 && iOfst!=p->endpoint.iOffset ){
+      memjrnlTruncate(pJfd, iOfst);
+    }
+    if( iOfst==0 && p->pFirst ){
+      assert( p->nChunkSize>iAmt );
+      memcpy((u8*)p->pFirst->zChunk, zBuf, iAmt);
+    }else{
+      while( nWrite>0 ){
+        FileChunk *pChunk = p->endpoint.pChunk;
+        int iChunkOffset = (int)(p->endpoint.iOffset%p->nChunkSize);
+        int iSpace = MIN(nWrite, p->nChunkSize - iChunkOffset);
+
+        assert( pChunk!=0 || iChunkOffset==0 );
+        if( iChunkOffset==0 ){
+          /* New chunk is required to extend the file. */
+          FileChunk *pNew = sqlite3_malloc(fileChunkSize(p->nChunkSize));
+          if( !pNew ){
+            return SQLITE_IOERR_NOMEM_BKPT;
+          }
+          pNew->pNext = 0;
+          if( pChunk ){
+            assert( p->pFirst );
+            pChunk->pNext = pNew;
+          }else{
+            assert( !p->pFirst );
+            p->pFirst = pNew;
+          }
+          pChunk = p->endpoint.pChunk = pNew;
+        }
+
+        assert( pChunk!=0 );
+        memcpy((u8*)pChunk->zChunk + iChunkOffset, zWrite, iSpace);
+        zWrite += iSpace;
+        nWrite -= iSpace;
+        p->endpoint.iOffset += iSpace;
+      }
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Truncate the in-memory file.
+*/
+static int memjrnlTruncate(sqlite3_file *pJfd, sqlite_int64 size){
+  MemJournal *p = (MemJournal *)pJfd;
+  assert( p->endpoint.pChunk==0 || p->endpoint.pChunk->pNext==0 );
+  if( size<p->endpoint.iOffset ){
+    FileChunk *pIter = 0;
+    if( size==0 ){
+      memjrnlFreeChunks(p->pFirst);
+      p->pFirst = 0;
+    }else{
+      i64 iOff = p->nChunkSize;
+      for(pIter=p->pFirst; ALWAYS(pIter) && iOff<size; pIter=pIter->pNext){
+        iOff += p->nChunkSize;
+      }
+      if( ALWAYS(pIter) ){
+        memjrnlFreeChunks(pIter->pNext);
+        pIter->pNext = 0;
+      }
+    }
+
+    p->endpoint.pChunk = pIter;
+    p->endpoint.iOffset = size;
+    p->readpoint.pChunk = 0;
+    p->readpoint.iOffset = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Close the file.
+*/
+static int memjrnlClose(sqlite3_file *pJfd){
+  MemJournal *p = (MemJournal *)pJfd;
+  memjrnlFreeChunks(p->pFirst);
+  return SQLITE_OK;
+}
+
+/*
+** Sync the file.
+**
+** If the real file has been created, call its xSync method. Otherwise,
+** syncing an in-memory journal is a no-op.
+*/
+static int memjrnlSync(sqlite3_file *pJfd, int flags){
+  UNUSED_PARAMETER2(pJfd, flags);
+  return SQLITE_OK;
+}
+
+/*
+** Query the size of the file in bytes.
+*/
+static int memjrnlFileSize(sqlite3_file *pJfd, sqlite_int64 *pSize){
+  MemJournal *p = (MemJournal *)pJfd;
+  *pSize = (sqlite_int64) p->endpoint.iOffset;
+  return SQLITE_OK;
+}
+
+/*
+** Table of methods for MemJournal sqlite3_file object.
+*/
+static const struct sqlite3_io_methods MemJournalMethods = {
+  1,                /* iVersion */
+  memjrnlClose,     /* xClose */
+  memjrnlRead,      /* xRead */
+  memjrnlWrite,     /* xWrite */
+  memjrnlTruncate,  /* xTruncate */
+  memjrnlSync,      /* xSync */
+  memjrnlFileSize,  /* xFileSize */
+  0,                /* xLock */
+  0,                /* xUnlock */
+  0,                /* xCheckReservedLock */
+  0,                /* xFileControl */
+  0,                /* xSectorSize */
+  0,                /* xDeviceCharacteristics */
+  0,                /* xShmMap */
+  0,                /* xShmLock */
+  0,                /* xShmBarrier */
+  0,                /* xShmUnmap */
+  0,                /* xFetch */
+  0                 /* xUnfetch */
+};
+
+/*
+** Open a journal file.
+**
+** The behaviour of the journal file depends on the value of parameter
+** nSpill. If nSpill is 0, then the journal file is always create and
+** accessed using the underlying VFS. If nSpill is less than zero, then
+** all content is always stored in main-memory. Finally, if nSpill is a
+** positive value, then the journal file is initially created in-memory
+** but may be flushed to disk later on. In this case the journal file is
+** flushed to disk either when it grows larger than nSpill bytes in size,
+** or when sqlite3JournalCreate() is called.
+*/
+SQLITE_PRIVATE int sqlite3JournalOpen(
+  sqlite3_vfs *pVfs,         /* The VFS to use for actual file I/O */
+  const char *zName,         /* Name of the journal file */
+  sqlite3_file *pJfd,        /* Preallocated, blank file handle */
+  int flags,                 /* Opening flags */
+  int nSpill                 /* Bytes buffered before opening the file */
+){
+  MemJournal *p = (MemJournal*)pJfd;
+
+  assert( zName || nSpill<0 || (flags & SQLITE_OPEN_EXCLUSIVE) );
+
+  /* Zero the file-handle object. If nSpill was passed zero, initialize
+  ** it using the sqlite3OsOpen() function of the underlying VFS. In this
+  ** case none of the code in this module is executed as a result of calls
+  ** made on the journal file-handle.  */
+  memset(p, 0, sizeof(MemJournal));
+  if( nSpill==0 ){
+    return sqlite3OsOpen(pVfs, zName, pJfd, flags, 0);
+  }
+
+  if( nSpill>0 ){
+    p->nChunkSize = nSpill;
+  }else{
+    p->nChunkSize = 8 + MEMJOURNAL_DFLT_FILECHUNKSIZE - sizeof(FileChunk);
+    assert( MEMJOURNAL_DFLT_FILECHUNKSIZE==fileChunkSize(p->nChunkSize) );
+  }
+
+  pJfd->pMethods = (const sqlite3_io_methods*)&MemJournalMethods;
+  p->nSpill = nSpill;
+  p->flags = flags;
+  p->zJournal = zName;
+  p->pVfs = pVfs;
+  return SQLITE_OK;
+}
+
+/*
+** Open an in-memory journal file.
+*/
+SQLITE_PRIVATE void sqlite3MemJournalOpen(sqlite3_file *pJfd){
+  sqlite3JournalOpen(0, 0, pJfd, 0, -1);
+}
+
+#if defined(SQLITE_ENABLE_ATOMIC_WRITE) \
+ || defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+/*
+** If the argument p points to a MemJournal structure that is not an
+** in-memory-only journal file (i.e. is one that was opened with a +ve
+** nSpill parameter or as SQLITE_OPEN_MAIN_JOURNAL), and the underlying
+** file has not yet been created, create it now.
+*/
+SQLITE_PRIVATE int sqlite3JournalCreate(sqlite3_file *pJfd){
+  int rc = SQLITE_OK;
+  MemJournal *p = (MemJournal*)pJfd;
+  if( pJfd->pMethods==&MemJournalMethods && (
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+     p->nSpill>0
+#else
+     /* While this appears to not be possible without ATOMIC_WRITE, the
+     ** paths are complex, so it seems prudent to leave the test in as
+     ** a NEVER(), in case our analysis is subtly flawed. */
+     NEVER(p->nSpill>0)
+#endif
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+     || (p->flags & SQLITE_OPEN_MAIN_JOURNAL)
+#endif
+  )){
+    rc = memjrnlCreateFile(p);
+  }
+  return rc;
+}
+#endif
+
+/*
+** The file-handle passed as the only argument is open on a journal file.
+** Return true if this "journal file" is currently stored in heap memory,
+** or false otherwise.
+*/
+SQLITE_PRIVATE int sqlite3JournalIsInMemory(sqlite3_file *p){
+  return p->pMethods==&MemJournalMethods;
+}
+
+/*
+** Return the number of bytes required to store a JournalFile that uses vfs
+** pVfs to create the underlying on-disk files.
+*/
+SQLITE_PRIVATE int sqlite3JournalSize(sqlite3_vfs *pVfs){
+  return MAX(pVfs->szOsFile, (int)sizeof(MemJournal));
+}
+
+/************** End of memjournal.c ******************************************/
+/************** Begin file walker.c ******************************************/
+/*
+** 2008 August 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used for walking the parser tree for
+** an SQL statement.
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdlib.h> */
+/* #include <string.h> */
+
+
+#if !defined(SQLITE_OMIT_WINDOWFUNC)
+/*
+** Walk all expressions linked into the list of Window objects passed
+** as the second argument.
+*/
+static int walkWindowList(Walker *pWalker, Window *pList, int bOneOnly){
+  Window *pWin;
+  for(pWin=pList; pWin; pWin=pWin->pNextWin){
+    int rc;
+    rc = sqlite3WalkExprList(pWalker, pWin->pOrderBy);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExprList(pWalker, pWin->pPartition);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExpr(pWalker, pWin->pFilter);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExpr(pWalker, pWin->pStart);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExpr(pWalker, pWin->pEnd);
+    if( rc ) return WRC_Abort;
+    if( bOneOnly ) break;
+  }
+  return WRC_Continue;
+}
+#endif
+
+/*
+** Walk an expression tree.  Invoke the callback once for each node
+** of the expression, while descending.  (In other words, the callback
+** is invoked before visiting children.)
+**
+** The return value from the callback should be one of the WRC_*
+** constants to specify how to proceed with the walk.
+**
+**    WRC_Continue      Continue descending down the tree.
+**
+**    WRC_Prune         Do not descend into child nodes, but allow
+**                      the walk to continue with sibling nodes.
+**
+**    WRC_Abort         Do no more callbacks.  Unwind the stack and
+**                      return from the top-level walk call.
+**
+** The return value from this routine is WRC_Abort to abandon the tree walk
+** and WRC_Continue to continue.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3WalkExprNN(Walker *pWalker, Expr *pExpr){
+  int rc;
+  testcase( ExprHasProperty(pExpr, EP_TokenOnly) );
+  testcase( ExprHasProperty(pExpr, EP_Reduced) );
+  while(1){
+    rc = pWalker->xExprCallback(pWalker, pExpr);
+    if( rc ) return rc & WRC_Abort;
+    if( !ExprHasProperty(pExpr,(EP_TokenOnly|EP_Leaf)) ){
+      assert( pExpr->x.pList==0 || pExpr->pRight==0 );
+      if( pExpr->pLeft && sqlite3WalkExprNN(pWalker, pExpr->pLeft) ){
+        return WRC_Abort;
+      }
+      if( pExpr->pRight ){
+        assert( !ExprHasProperty(pExpr, EP_WinFunc) );
+        pExpr = pExpr->pRight;
+        continue;
+      }else if( ExprUseXSelect(pExpr) ){
+        assert( !ExprHasProperty(pExpr, EP_WinFunc) );
+        if( sqlite3WalkSelect(pWalker, pExpr->x.pSelect) ) return WRC_Abort;
+      }else{
+        if( pExpr->x.pList ){
+          if( sqlite3WalkExprList(pWalker, pExpr->x.pList) ) return WRC_Abort;
+        }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        if( ExprHasProperty(pExpr, EP_WinFunc) ){
+          if( walkWindowList(pWalker, pExpr->y.pWin, 1) ) return WRC_Abort;
+        }
+#endif
+      }
+    }
+    break;
+  }
+  return WRC_Continue;
+}
+SQLITE_PRIVATE int sqlite3WalkExpr(Walker *pWalker, Expr *pExpr){
+  return pExpr ? sqlite3WalkExprNN(pWalker,pExpr) : WRC_Continue;
+}
+
+/*
+** Call sqlite3WalkExpr() for every expression in list p or until
+** an abort request is seen.
+*/
+SQLITE_PRIVATE int sqlite3WalkExprList(Walker *pWalker, ExprList *p){
+  int i;
+  struct ExprList_item *pItem;
+  if( p ){
+    for(i=p->nExpr, pItem=p->a; i>0; i--, pItem++){
+      if( sqlite3WalkExpr(pWalker, pItem->pExpr) ) return WRC_Abort;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** This is a no-op callback for Walker->xSelectCallback2.  If this
+** callback is set, then the Select->pWinDefn list is traversed.
+*/
+SQLITE_PRIVATE void sqlite3WalkWinDefnDummyCallback(Walker *pWalker, Select *p){
+  UNUSED_PARAMETER(pWalker);
+  UNUSED_PARAMETER(p);
+  /* No-op */
+}
+
+/*
+** Walk all expressions associated with SELECT statement p.  Do
+** not invoke the SELECT callback on p, but do (of course) invoke
+** any expr callbacks and SELECT callbacks that come from subqueries.
+** Return WRC_Abort or WRC_Continue.
+*/
+SQLITE_PRIVATE int sqlite3WalkSelectExpr(Walker *pWalker, Select *p){
+  if( sqlite3WalkExprList(pWalker, p->pEList) ) return WRC_Abort;
+  if( sqlite3WalkExpr(pWalker, p->pWhere) ) return WRC_Abort;
+  if( sqlite3WalkExprList(pWalker, p->pGroupBy) ) return WRC_Abort;
+  if( sqlite3WalkExpr(pWalker, p->pHaving) ) return WRC_Abort;
+  if( sqlite3WalkExprList(pWalker, p->pOrderBy) ) return WRC_Abort;
+  if( sqlite3WalkExpr(pWalker, p->pLimit) ) return WRC_Abort;
+#if !defined(SQLITE_OMIT_WINDOWFUNC)
+  if( p->pWinDefn ){
+    Parse *pParse;
+    if( pWalker->xSelectCallback2==sqlite3WalkWinDefnDummyCallback
+     || ((pParse = pWalker->pParse)!=0 && IN_RENAME_OBJECT)
+#ifndef SQLITE_OMIT_CTE
+     || pWalker->xSelectCallback2==sqlite3SelectPopWith
+#endif
+    ){
+      /* The following may return WRC_Abort if there are unresolvable
+      ** symbols (e.g. a table that does not exist) in a window definition. */
+      int rc = walkWindowList(pWalker, p->pWinDefn, 0);
+      return rc;
+    }
+  }
+#endif
+  return WRC_Continue;
+}
+
+/*
+** Walk the parse trees associated with all subqueries in the
+** FROM clause of SELECT statement p.  Do not invoke the select
+** callback on p, but do invoke it on each FROM clause subquery
+** and on any subqueries further down in the tree.  Return
+** WRC_Abort or WRC_Continue;
+*/
+SQLITE_PRIVATE int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
+  SrcList *pSrc;
+  int i;
+  SrcItem *pItem;
+
+  pSrc = p->pSrc;
+  if( ALWAYS(pSrc) ){
+    for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
+      if( pItem->fg.isSubquery
+       && sqlite3WalkSelect(pWalker, pItem->u4.pSubq->pSelect)
+      ){
+        return WRC_Abort;
+      }
+      if( pItem->fg.isTabFunc
+       && sqlite3WalkExprList(pWalker, pItem->u1.pFuncArg)
+      ){
+        return WRC_Abort;
+      }
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Call sqlite3WalkExpr() for every expression in Select statement p.
+** Invoke sqlite3WalkSelect() for subqueries in the FROM clause and
+** on the compound select chain, p->pPrior.
+**
+** If it is not NULL, the xSelectCallback() callback is invoked before
+** the walk of the expressions and FROM clause. The xSelectCallback2()
+** method is invoked following the walk of the expressions and FROM clause,
+** but only if both xSelectCallback and xSelectCallback2 are both non-NULL
+** and if the expressions and FROM clause both return WRC_Continue;
+**
+** Return WRC_Continue under normal conditions.  Return WRC_Abort if
+** there is an abort request.
+**
+** If the Walker does not have an xSelectCallback() then this routine
+** is a no-op returning WRC_Continue.
+*/
+SQLITE_PRIVATE int sqlite3WalkSelect(Walker *pWalker, Select *p){
+  int rc;
+  if( p==0 ) return WRC_Continue;
+  if( pWalker->xSelectCallback==0 ) return WRC_Continue;
+  do{
+    rc = pWalker->xSelectCallback(pWalker, p);
+    if( rc ) return rc & WRC_Abort;
+    if( sqlite3WalkSelectExpr(pWalker, p)
+     || sqlite3WalkSelectFrom(pWalker, p)
+    ){
+      return WRC_Abort;
+    }
+    if( pWalker->xSelectCallback2 ){
+      pWalker->xSelectCallback2(pWalker, p);
+    }
+    p = p->pPrior;
+  }while( p!=0 );
+  return WRC_Continue;
+}
+
+/* Increase the walkerDepth when entering a subquery, and
+** decrease when leaving the subquery.
+*/
+SQLITE_PRIVATE int sqlite3WalkerDepthIncrease(Walker *pWalker, Select *pSelect){
+  UNUSED_PARAMETER(pSelect);
+  pWalker->walkerDepth++;
+  return WRC_Continue;
+}
+SQLITE_PRIVATE void sqlite3WalkerDepthDecrease(Walker *pWalker, Select *pSelect){
+  UNUSED_PARAMETER(pSelect);
+  pWalker->walkerDepth--;
+}
+
+
+/*
+** No-op routine for the parse-tree walker.
+**
+** When this routine is the Walker.xExprCallback then expression trees
+** are walked without any actions being taken at each node.  Presumably,
+** when this routine is used for Walker.xExprCallback then
+** Walker.xSelectCallback is set to do something useful for every
+** subquery in the parser tree.
+*/
+SQLITE_PRIVATE int sqlite3ExprWalkNoop(Walker *NotUsed, Expr *NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  return WRC_Continue;
+}
+
+/*
+** No-op routine for the parse-tree walker for SELECT statements.
+** subquery in the parser tree.
+*/
+SQLITE_PRIVATE int sqlite3SelectWalkNoop(Walker *NotUsed, Select *NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  return WRC_Continue;
+}
+
+/************** End of walker.c **********************************************/
+/************** Begin file resolve.c *****************************************/
+/*
+** 2008 August 18
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains routines used for walking the parser tree and
+** resolve all identifiers by associating them with a particular
+** table and column.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** Magic table number to mean the EXCLUDED table in an UPSERT statement.
+*/
+#define EXCLUDED_TABLE_NUMBER  2
+
+/*
+** Walk the expression tree pExpr and increase the aggregate function
+** depth (the Expr.op2 field) by N on every TK_AGG_FUNCTION node.
+** This needs to occur when copying a TK_AGG_FUNCTION node from an
+** outer query into an inner subquery.
+**
+** incrAggFunctionDepth(pExpr,n) is the main routine.  incrAggDepth(..)
+** is a helper function - a callback for the tree walker.
+**
+** See also the sqlite3WindowExtraAggFuncDepth() routine in window.c
+*/
+static int incrAggDepth(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_AGG_FUNCTION ) pExpr->op2 += pWalker->u.n;
+  return WRC_Continue;
+}
+static void incrAggFunctionDepth(Expr *pExpr, int N){
+  if( N>0 ){
+    Walker w;
+    memset(&w, 0, sizeof(w));
+    w.xExprCallback = incrAggDepth;
+    w.u.n = N;
+    sqlite3WalkExpr(&w, pExpr);
+  }
+}
+
+/*
+** Turn the pExpr expression into an alias for the iCol-th column of the
+** result set in pEList.
+**
+** If the reference is followed by a COLLATE operator, then make sure
+** the COLLATE operator is preserved.  For example:
+**
+**     SELECT a+b, c+d FROM t1 ORDER BY 1 COLLATE nocase;
+**
+** Should be transformed into:
+**
+**     SELECT a+b, c+d FROM t1 ORDER BY (a+b) COLLATE nocase;
+**
+** The nSubquery parameter specifies how many levels of subquery the
+** alias is removed from the original expression.  The usual value is
+** zero but it might be more if the alias is contained within a subquery
+** of the original expression.  The Expr.op2 field of TK_AGG_FUNCTION
+** structures must be increased by the nSubquery amount.
+*/
+static void resolveAlias(
+  Parse *pParse,         /* Parsing context */
+  ExprList *pEList,      /* A result set */
+  int iCol,              /* A column in the result set.  0..pEList->nExpr-1 */
+  Expr *pExpr,           /* Transform this into an alias to the result set */
+  int nSubquery          /* Number of subqueries that the label is moving */
+){
+  Expr *pOrig;           /* The iCol-th column of the result set */
+  Expr *pDup;            /* Copy of pOrig */
+  sqlite3 *db;           /* The database connection */
+
+  assert( iCol>=0 && iCol<pEList->nExpr );
+  pOrig = pEList->a[iCol].pExpr;
+  assert( pOrig!=0 );
+  assert( !ExprHasProperty(pExpr, EP_Reduced|EP_TokenOnly) );
+  if( pExpr->pAggInfo ) return;
+  db = pParse->db;
+  pDup = sqlite3ExprDup(db, pOrig, 0);
+  if( db->mallocFailed ){
+    sqlite3ExprDelete(db, pDup);
+    pDup = 0;
+  }else{
+    Expr temp;
+    incrAggFunctionDepth(pDup, nSubquery);
+    if( pExpr->op==TK_COLLATE ){
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      pDup = sqlite3ExprAddCollateString(pParse, pDup, pExpr->u.zToken);
+    }
+    memcpy(&temp, pDup, sizeof(Expr));
+    memcpy(pDup, pExpr, sizeof(Expr));
+    memcpy(pExpr, &temp, sizeof(Expr));
+    if( ExprHasProperty(pExpr, EP_WinFunc) ){
+      if( ALWAYS(pExpr->y.pWin!=0) ){
+        pExpr->y.pWin->pOwner = pExpr;
+      }
+    }
+    sqlite3ExprDeferredDelete(pParse, pDup);
+  }
+}
+
+/*
+** Subqueries store the original database, table and column names for their
+** result sets in ExprList.a[].zSpan, in the form "DATABASE.TABLE.COLUMN",
+** and mark the expression-list item by setting ExprList.a[].fg.eEName
+** to ENAME_TAB.
+**
+** Check to see if the zSpan/eEName of the expression-list item passed to this
+** routine matches the zDb, zTab, and zCol.  If any of zDb, zTab, and zCol are
+** NULL then those fields will match anything. Return true if there is a match,
+** or false otherwise.
+**
+** SF_NestedFrom subqueries also store an entry for the implicit rowid (or
+** _rowid_, or oid) column by setting ExprList.a[].fg.eEName to ENAME_ROWID,
+** and setting zSpan to "DATABASE.TABLE.<rowid-alias>". This type of pItem
+** argument matches if zCol is a rowid alias. If it is not NULL, (*pbRowid)
+** is set to 1 if there is this kind of match.
+*/
+SQLITE_PRIVATE int sqlite3MatchEName(
+  const struct ExprList_item *pItem,
+  const char *zCol,
+  const char *zTab,
+  const char *zDb,
+  int *pbRowid
+){
+  int n;
+  const char *zSpan;
+  int eEName = pItem->fg.eEName;
+  if( eEName!=ENAME_TAB && (eEName!=ENAME_ROWID || NEVER(pbRowid==0)) ){
+    return 0;
+  }
+  assert( pbRowid==0 || *pbRowid==0 );
+  zSpan = pItem->zEName;
+  for(n=0; ALWAYS(zSpan[n]) && zSpan[n]!='.'; n++){}
+  if( zDb && (sqlite3StrNICmp(zSpan, zDb, n)!=0 || zDb[n]!=0) ){
+    return 0;
+  }
+  zSpan += n+1;
+  for(n=0; ALWAYS(zSpan[n]) && zSpan[n]!='.'; n++){}
+  if( zTab && (sqlite3StrNICmp(zSpan, zTab, n)!=0 || zTab[n]!=0) ){
+    return 0;
+  }
+  zSpan += n+1;
+  if( zCol ){
+    if( eEName==ENAME_TAB && sqlite3StrICmp(zSpan, zCol)!=0 ) return 0;
+    if( eEName==ENAME_ROWID && sqlite3IsRowid(zCol)==0 ) return 0;
+  }
+  if( eEName==ENAME_ROWID ) *pbRowid = 1;
+  return 1;
+}
+
+/*
+** Return TRUE if the double-quoted string  mis-feature should be supported.
+*/
+static int areDoubleQuotedStringsEnabled(sqlite3 *db, NameContext *pTopNC){
+  if( db->init.busy ) return 1;  /* Always support for legacy schemas */
+  if( pTopNC->ncFlags & NC_IsDDL ){
+    /* Currently parsing a DDL statement */
+    if( sqlite3WritableSchema(db) && (db->flags & SQLITE_DqsDML)!=0 ){
+      return 1;
+    }
+    return (db->flags & SQLITE_DqsDDL)!=0;
+  }else{
+    /* Currently parsing a DML statement */
+    return (db->flags & SQLITE_DqsDML)!=0;
+  }
+}
+
+/*
+** The argument is guaranteed to be a non-NULL Expr node of type TK_COLUMN.
+** return the appropriate colUsed mask.
+*/
+SQLITE_PRIVATE Bitmask sqlite3ExprColUsed(Expr *pExpr){
+  int n;
+  Table *pExTab;
+
+  n = pExpr->iColumn;
+  assert( ExprUseYTab(pExpr) );
+  pExTab = pExpr->y.pTab;
+  assert( pExTab!=0 );
+  assert( n < pExTab->nCol );
+  if( (pExTab->tabFlags & TF_HasGenerated)!=0
+   && (pExTab->aCol[n].colFlags & COLFLAG_GENERATED)!=0
+  ){
+    testcase( pExTab->nCol==BMS-1 );
+    testcase( pExTab->nCol==BMS );
+    return pExTab->nCol>=BMS ? ALLBITS : MASKBIT(pExTab->nCol)-1;
+  }else{
+    testcase( n==BMS-1 );
+    testcase( n==BMS );
+    if( n>=BMS ) n = BMS-1;
+    return ((Bitmask)1)<<n;
+  }
+}
+
+/*
+** Create a new expression term for the column specified by pMatch and
+** iColumn.  Append this new expression term to the FULL JOIN Match set
+** in *ppList.  Create a new *ppList if this is the first term in the
+** set.
+*/
+static void extendFJMatch(
+  Parse *pParse,          /* Parsing context */
+  ExprList **ppList,      /* ExprList to extend */
+  SrcItem *pMatch,        /* Source table containing the column */
+  i16 iColumn             /* The column number */
+){
+  Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0);
+  if( pNew ){
+    pNew->iTable = pMatch->iCursor;
+    pNew->iColumn = iColumn;
+    pNew->y.pTab = pMatch->pSTab;
+    assert( (pMatch->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 );
+    ExprSetProperty(pNew, EP_CanBeNull);
+    *ppList = sqlite3ExprListAppend(pParse, *ppList, pNew);
+  }
+}
+
+/*
+** Return TRUE (non-zero) if zTab is a valid name for the schema table pTab.
+*/
+static SQLITE_NOINLINE int isValidSchemaTableName(
+  const char *zTab,         /* Name as it appears in the SQL */
+  Table *pTab,              /* The schema table we are trying to match */
+  const char *zDb           /* non-NULL if a database qualifier is present */
+){
+  const char *zLegacy;
+  assert( pTab!=0 );
+  assert( pTab->tnum==1 );
+  if( sqlite3StrNICmp(zTab, "sqlite_", 7)!=0 ) return 0;
+  zLegacy = pTab->zName;
+  if( strcmp(zLegacy+7, &LEGACY_TEMP_SCHEMA_TABLE[7])==0 ){
+    if( sqlite3StrICmp(zTab+7, &PREFERRED_TEMP_SCHEMA_TABLE[7])==0 ){
+      return 1;
+    }
+    if( zDb==0 ) return 0;
+    if( sqlite3StrICmp(zTab+7, &LEGACY_SCHEMA_TABLE[7])==0 ) return 1;
+    if( sqlite3StrICmp(zTab+7, &PREFERRED_SCHEMA_TABLE[7])==0 ) return 1;
+  }else{
+    if( sqlite3StrICmp(zTab+7, &PREFERRED_SCHEMA_TABLE[7])==0 ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
+** that name in the set of source tables in pSrcList and make the pExpr
+** expression node refer back to that source column.  The following changes
+** are made to pExpr:
+**
+**    pExpr->iDb           Set the index in db->aDb[] of the database X
+**                         (even if X is implied).
+**    pExpr->iTable        Set to the cursor number for the table obtained
+**                         from pSrcList.
+**    pExpr->y.pTab        Points to the Table structure of X.Y (even if
+**                         X and/or Y are implied.)
+**    pExpr->iColumn       Set to the column number within the table.
+**    pExpr->op            Set to TK_COLUMN.
+**    pExpr->pLeft         Any expression this points to is deleted
+**    pExpr->pRight        Any expression this points to is deleted.
+**
+** The zDb variable is the name of the database (the "X").  This value may be
+** NULL meaning that name is of the form Y.Z or Z.  Any available database
+** can be used.  The zTable variable is the name of the table (the "Y").  This
+** value can be NULL if zDb is also NULL.  If zTable is NULL it
+** means that the form of the name is Z and that columns from any table
+** can be used.
+**
+** If the name cannot be resolved unambiguously, leave an error message
+** in pParse and return WRC_Abort.  Return WRC_Prune on success.
+*/
+static int lookupName(
+  Parse *pParse,       /* The parsing context */
+  const char *zDb,     /* Name of the database containing table, or NULL */
+  const char *zTab,    /* Name of table containing column, or NULL */
+  const Expr *pRight,  /* Name of the column. */
+  NameContext *pNC,    /* The name context used to resolve the name */
+  Expr *pExpr          /* Make this EXPR node point to the selected column */
+){
+  int i, j;                         /* Loop counters */
+  int cnt = 0;                      /* Number of matching column names */
+  int cntTab = 0;                   /* Number of potential "rowid" matches */
+  int nSubquery = 0;                /* How many levels of subquery */
+  sqlite3 *db = pParse->db;         /* The database connection */
+  SrcItem *pItem;                   /* Use for looping over pSrcList items */
+  SrcItem *pMatch = 0;              /* The matching pSrcList item */
+  NameContext *pTopNC = pNC;        /* First namecontext in the list */
+  Schema *pSchema = 0;              /* Schema of the expression */
+  int eNewExprOp = TK_COLUMN;       /* New value for pExpr->op on success */
+  Table *pTab = 0;                  /* Table holding the row */
+  Column *pCol;                     /* A column of pTab */
+  ExprList *pFJMatch = 0;           /* Matches for FULL JOIN .. USING */
+  const char *zCol = pRight->u.zToken;
+
+  assert( pNC );     /* the name context cannot be NULL. */
+  assert( zCol );    /* The Z in X.Y.Z cannot be NULL */
+  assert( zDb==0 || zTab!=0 );
+  assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+
+  /* Initialize the node to no-match */
+  pExpr->iTable = -1;
+  ExprSetVVAProperty(pExpr, EP_NoReduce);
+
+  /* Translate the schema name in zDb into a pointer to the corresponding
+  ** schema.  If not found, pSchema will remain NULL and nothing will match
+  ** resulting in an appropriate error message toward the end of this routine
+  */
+  if( zDb ){
+    testcase( pNC->ncFlags & NC_PartIdx );
+    testcase( pNC->ncFlags & NC_IsCheck );
+    if( (pNC->ncFlags & (NC_PartIdx|NC_IsCheck))!=0 ){
+      /* Silently ignore database qualifiers inside CHECK constraints and
+      ** partial indices.  Do not raise errors because that might break
+      ** legacy and because it does not hurt anything to just ignore the
+      ** database name. */
+      zDb = 0;
+    }else{
+      for(i=0; i<db->nDb; i++){
+        assert( db->aDb[i].zDbSName );
+        if( sqlite3StrICmp(db->aDb[i].zDbSName,zDb)==0 ){
+          pSchema = db->aDb[i].pSchema;
+          break;
+        }
+      }
+      if( i==db->nDb && sqlite3StrICmp("main", zDb)==0 ){
+        /* This branch is taken when the main database has been renamed
+        ** using SQLITE_DBCONFIG_MAINDBNAME. */
+        pSchema = db->aDb[0].pSchema;
+        zDb = db->aDb[0].zDbSName;
+      }
+    }
+  }
+
+  /* Start at the inner-most context and move outward until a match is found */
+  assert( pNC && cnt==0 );
+  do{
+    ExprList *pEList;
+    SrcList *pSrcList = pNC->pSrcList;
+
+    if( pSrcList ){
+      for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
+        u8 hCol;
+        pTab = pItem->pSTab;
+        assert( pTab!=0 && pTab->zName!=0 );
+        assert( pTab->nCol>0 || pParse->nErr );
+        assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem));
+        if( pItem->fg.isNestedFrom ){
+          /* In this case, pItem is a subquery that has been formed from a
+          ** parenthesized subset of the FROM clause terms.  Example:
+          **   .... FROM t1 LEFT JOIN (t2 RIGHT JOIN t3 USING(x)) USING(y) ...
+          **                          \_________________________/
+          **             This pItem -------------^
+          */
+          int hit = 0;
+          Select *pSel;
+          assert( pItem->fg.isSubquery );
+          assert( pItem->u4.pSubq!=0 );
+          pSel = pItem->u4.pSubq->pSelect;
+          assert( pSel!=0 );
+          pEList = pSel->pEList;
+          assert( pEList!=0 );
+          assert( pEList->nExpr==pTab->nCol );
+          for(j=0; j<pEList->nExpr; j++){
+            int bRowid = 0;       /* True if possible rowid match */
+            if( !sqlite3MatchEName(&pEList->a[j], zCol, zTab, zDb, &bRowid) ){
+              continue;
+            }
+            if( bRowid==0 ){
+              if( cnt>0 ){
+                if( pItem->fg.isUsing==0
+                 || sqlite3IdListIndex(pItem->u3.pUsing, zCol)<0
+                ){
+                  /* Two or more tables have the same column name which is
+                  ** not joined by USING.  This is an error.  Signal as much
+                  ** by clearing pFJMatch and letting cnt go above 1. */
+                  sqlite3ExprListDelete(db, pFJMatch);
+                  pFJMatch = 0;
+                }else
+                if( (pItem->fg.jointype & JT_RIGHT)==0 ){
+                  /* An INNER or LEFT JOIN.  Use the left-most table */
+                  continue;
+                }else
+                if( (pItem->fg.jointype & JT_LEFT)==0 ){
+                  /* A RIGHT JOIN.  Use the right-most table */
+                  cnt = 0;
+                  sqlite3ExprListDelete(db, pFJMatch);
+                  pFJMatch = 0;
+                }else{
+                  /* For a FULL JOIN, we must construct a coalesce() func */
+                  extendFJMatch(pParse, &pFJMatch, pMatch, pExpr->iColumn);
+                }
+              }
+              cnt++;
+              hit = 1;
+            }else if( cnt>0 ){
+              /* This is a potential rowid match, but there has already been
+              ** a real match found. So this can be ignored.  */
+              continue;
+            }
+            cntTab++;
+            pMatch = pItem;
+            pExpr->iColumn = j;
+            pEList->a[j].fg.bUsed = 1;
+
+            /* rowid cannot be part of a USING clause - assert() this. */
+            assert( bRowid==0 || pEList->a[j].fg.bUsingTerm==0 );
+            if( pEList->a[j].fg.bUsingTerm ) break;
+          }
+          if( hit || zTab==0 ) continue;
+        }
+        assert( zDb==0 || zTab!=0 );
+        if( zTab ){
+          if( zDb ){
+            if( pTab->pSchema!=pSchema ) continue;
+            if( pSchema==0 && strcmp(zDb,"*")!=0 ) continue;
+          }
+          if( pItem->zAlias!=0 ){
+            if( sqlite3StrICmp(zTab, pItem->zAlias)!=0 ){
+              continue;
+            }
+          }else if( sqlite3StrICmp(zTab, pTab->zName)!=0 ){
+            if( pTab->tnum!=1 ) continue;
+            if( !isValidSchemaTableName(zTab, pTab, zDb) ) continue;
+          }
+          assert( ExprUseYTab(pExpr) );
+          if( IN_RENAME_OBJECT && pItem->zAlias ){
+            sqlite3RenameTokenRemap(pParse, 0, (void*)&pExpr->y.pTab);
+          }
+        }
+        hCol = sqlite3StrIHash(zCol);
+        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
+          if( pCol->hName==hCol
+           && sqlite3StrICmp(pCol->zCnName, zCol)==0
+          ){
+            if( cnt>0 ){
+              if( pItem->fg.isUsing==0
+               || sqlite3IdListIndex(pItem->u3.pUsing, zCol)<0
+              ){
+                /* Two or more tables have the same column name which is
+                ** not joined by USING.  This is an error.  Signal as much
+                ** by clearing pFJMatch and letting cnt go above 1. */
+                sqlite3ExprListDelete(db, pFJMatch);
+                pFJMatch = 0;
+              }else
+              if( (pItem->fg.jointype & JT_RIGHT)==0 ){
+                /* An INNER or LEFT JOIN.  Use the left-most table */
+                continue;
+              }else
+              if( (pItem->fg.jointype & JT_LEFT)==0 ){
+                /* A RIGHT JOIN.  Use the right-most table */
+                cnt = 0;
+                sqlite3ExprListDelete(db, pFJMatch);
+                pFJMatch = 0;
+              }else{
+                /* For a FULL JOIN, we must construct a coalesce() func */
+                extendFJMatch(pParse, &pFJMatch, pMatch, pExpr->iColumn);
+              }
+            }
+            cnt++;
+            pMatch = pItem;
+            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
+            pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
+            if( pItem->fg.isNestedFrom ){
+              sqlite3SrcItemColumnUsed(pItem, j);
+            }
+            break;
+          }
+        }
+        if( 0==cnt && VisibleRowid(pTab) ){
+          /* pTab is a potential ROWID match.  Keep track of it and match
+          ** the ROWID later if that seems appropriate.  (Search for "cntTab"
+          ** to find related code.)  Only allow a ROWID match if there is
+          ** a single ROWID match candidate.
+          */
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+          /* In SQLITE_ALLOW_ROWID_IN_VIEW mode, allow a ROWID match
+          ** if there is a single VIEW candidate or if there is a single
+          ** non-VIEW candidate plus multiple VIEW candidates.  In other
+          ** words non-VIEW candidate terms take precedence over VIEWs.
+          */
+          if( cntTab==0
+           || (cntTab==1
+               && pMatch!=0
+               && ALWAYS(pMatch->pSTab!=0)
+               && (pMatch->pSTab->tabFlags & TF_Ephemeral)!=0
+               && (pTab->tabFlags & TF_Ephemeral)==0)
+          ){
+            cntTab = 1;
+            pMatch = pItem;
+          }else{
+            cntTab++;
+          }
+#else
+          /* The (much more common) non-SQLITE_ALLOW_ROWID_IN_VIEW case is
+          ** simpler since we require exactly one candidate, which will
+          ** always be a non-VIEW
+          */
+          cntTab++;
+          pMatch = pItem;
+#endif
+        }
+      }
+      if( pMatch ){
+        pExpr->iTable = pMatch->iCursor;
+        assert( ExprUseYTab(pExpr) );
+        pExpr->y.pTab = pMatch->pSTab;
+        if( (pMatch->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 ){
+          ExprSetProperty(pExpr, EP_CanBeNull);
+        }
+        pSchema = pExpr->y.pTab->pSchema;
+      }
+    } /* if( pSrcList ) */
+
+#if !defined(SQLITE_OMIT_TRIGGER) || !defined(SQLITE_OMIT_UPSERT)
+    /* If we have not already resolved the name, then maybe
+    ** it is a new.* or old.* trigger argument reference.  Or
+    ** maybe it is an excluded.* from an upsert.  Or maybe it is
+    ** a reference in the RETURNING clause to a table being modified.
+    */
+    if( cnt==0 && zDb==0 ){
+      pTab = 0;
+#ifndef SQLITE_OMIT_TRIGGER
+      if( pParse->pTriggerTab!=0 ){
+        int op = pParse->eTriggerOp;
+        assert( op==TK_DELETE || op==TK_UPDATE || op==TK_INSERT );
+        if( pParse->bReturning ){
+          if( (pNC->ncFlags & NC_UBaseReg)!=0
+           && ALWAYS(zTab==0
+                     || sqlite3StrICmp(zTab,pParse->pTriggerTab->zName)==0
+                     || isValidSchemaTableName(zTab, pParse->pTriggerTab, 0))
+          ){
+            pExpr->iTable = op!=TK_DELETE;
+            pTab = pParse->pTriggerTab;
+          }
+        }else if( op!=TK_DELETE && zTab && sqlite3StrICmp("new",zTab) == 0 ){
+          pExpr->iTable = 1;
+          pTab = pParse->pTriggerTab;
+        }else if( op!=TK_INSERT && zTab && sqlite3StrICmp("old",zTab)==0 ){
+          pExpr->iTable = 0;
+          pTab = pParse->pTriggerTab;
+        }
+      }
+#endif /* SQLITE_OMIT_TRIGGER */
+#ifndef SQLITE_OMIT_UPSERT
+      if( (pNC->ncFlags & NC_UUpsert)!=0 && zTab!=0 ){
+        Upsert *pUpsert = pNC->uNC.pUpsert;
+        if( pUpsert && sqlite3StrICmp("excluded",zTab)==0 ){
+          pTab = pUpsert->pUpsertSrc->a[0].pSTab;
+          pExpr->iTable = EXCLUDED_TABLE_NUMBER;
+        }
+      }
+#endif /* SQLITE_OMIT_UPSERT */
+
+      if( pTab ){
+        int iCol;
+        u8 hCol = sqlite3StrIHash(zCol);
+        pSchema = pTab->pSchema;
+        cntTab++;
+        for(iCol=0, pCol=pTab->aCol; iCol<pTab->nCol; iCol++, pCol++){
+          if( pCol->hName==hCol
+           && sqlite3StrICmp(pCol->zCnName, zCol)==0
+          ){
+            if( iCol==pTab->iPKey ){
+              iCol = -1;
+            }
+            break;
+          }
+        }
+        if( iCol>=pTab->nCol && sqlite3IsRowid(zCol) && VisibleRowid(pTab) ){
+          /* IMP: R-51414-32910 */
+          iCol = -1;
+        }
+        if( iCol<pTab->nCol ){
+          cnt++;
+          pMatch = 0;
+#ifndef SQLITE_OMIT_UPSERT
+          if( pExpr->iTable==EXCLUDED_TABLE_NUMBER ){
+            testcase( iCol==(-1) );
+            assert( ExprUseYTab(pExpr) );
+            if( IN_RENAME_OBJECT ){
+              pExpr->iColumn = iCol;
+              pExpr->y.pTab = pTab;
+              eNewExprOp = TK_COLUMN;
+            }else{
+              pExpr->iTable = pNC->uNC.pUpsert->regData +
+                 sqlite3TableColumnToStorage(pTab, iCol);
+              eNewExprOp = TK_REGISTER;
+            }
+          }else
+#endif /* SQLITE_OMIT_UPSERT */
+          {
+            assert( ExprUseYTab(pExpr) );
+            pExpr->y.pTab = pTab;
+            if( pParse->bReturning ){
+              eNewExprOp = TK_REGISTER;
+              pExpr->op2 = TK_COLUMN;
+              pExpr->iColumn = iCol;
+              pExpr->iTable = pNC->uNC.iBaseReg + (pTab->nCol+1)*pExpr->iTable +
+                 sqlite3TableColumnToStorage(pTab, iCol) + 1;
+            }else{
+              pExpr->iColumn = (i16)iCol;
+              eNewExprOp = TK_TRIGGER;
+#ifndef SQLITE_OMIT_TRIGGER
+              if( iCol<0 ){
+                pExpr->affExpr = SQLITE_AFF_INTEGER;
+              }else if( pExpr->iTable==0 ){
+                testcase( iCol==31 );
+                testcase( iCol==32 );
+                pParse->oldmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
+              }else{
+                testcase( iCol==31 );
+                testcase( iCol==32 );
+                pParse->newmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
+              }
+#endif /* SQLITE_OMIT_TRIGGER */
+            }
+          }
+        }
+      }
+    }
+#endif /* !defined(SQLITE_OMIT_TRIGGER) || !defined(SQLITE_OMIT_UPSERT) */
+
+    /*
+    ** Perhaps the name is a reference to the ROWID
+    */
+    if( cnt==0
+     && cntTab>=1
+     && pMatch
+     && (pNC->ncFlags & (NC_IdxExpr|NC_GenCol))==0
+     && sqlite3IsRowid(zCol)
+     && ALWAYS(VisibleRowid(pMatch->pSTab) || pMatch->fg.isNestedFrom)
+    ){
+      cnt = cntTab;
+#if SQLITE_ALLOW_ROWID_IN_VIEW+0==2
+      if( pMatch->pSTab!=0 && IsView(pMatch->pSTab) ){
+        eNewExprOp = TK_NULL;
+      }
+#endif
+      if( pMatch->fg.isNestedFrom==0 ) pExpr->iColumn = -1;
+      pExpr->affExpr = SQLITE_AFF_INTEGER;
+    }
+
+    /*
+    ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
+    ** might refer to an result-set alias.  This happens, for example, when
+    ** we are resolving names in the WHERE clause of the following command:
+    **
+    **     SELECT a+b AS x FROM table WHERE x<10;
+    **
+    ** In cases like this, replace pExpr with a copy of the expression that
+    ** forms the result set entry ("a+b" in the example) and return immediately.
+    ** Note that the expression in the result set should have already been
+    ** resolved by the time the WHERE clause is resolved.
+    **
+    ** The ability to use an output result-set column in the WHERE, GROUP BY,
+    ** or HAVING clauses, or as part of a larger expression in the ORDER BY
+    ** clause is not standard SQL.  This is a (goofy) SQLite extension, that
+    ** is supported for backwards compatibility only. Hence, we issue a warning
+    ** on sqlite3_log() whenever the capability is used.
+    */
+    if( cnt==0
+     && (pNC->ncFlags & NC_UEList)!=0
+     && zTab==0
+    ){
+      pEList = pNC->uNC.pEList;
+      assert( pEList!=0 );
+      for(j=0; j<pEList->nExpr; j++){
+        char *zAs = pEList->a[j].zEName;
+        if( pEList->a[j].fg.eEName==ENAME_NAME
+         && sqlite3_stricmp(zAs, zCol)==0
+        ){
+          Expr *pOrig;
+          assert( pExpr->pLeft==0 && pExpr->pRight==0 );
+          assert( ExprUseXList(pExpr)==0 || pExpr->x.pList==0 );
+          assert( ExprUseXSelect(pExpr)==0 || pExpr->x.pSelect==0 );
+          pOrig = pEList->a[j].pExpr;
+          if( (pNC->ncFlags&NC_AllowAgg)==0 && ExprHasProperty(pOrig, EP_Agg) ){
+            sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
+            return WRC_Abort;
+          }
+          if( ExprHasProperty(pOrig, EP_Win)
+           && ((pNC->ncFlags&NC_AllowWin)==0 || pNC!=pTopNC )
+          ){
+            sqlite3ErrorMsg(pParse, "misuse of aliased window function %s",zAs);
+            return WRC_Abort;
+          }
+          if( sqlite3ExprVectorSize(pOrig)!=1 ){
+            sqlite3ErrorMsg(pParse, "row value misused");
+            return WRC_Abort;
+          }
+          resolveAlias(pParse, pEList, j, pExpr, nSubquery);
+          cnt = 1;
+          pMatch = 0;
+          assert( zTab==0 && zDb==0 );
+          if( IN_RENAME_OBJECT ){
+            sqlite3RenameTokenRemap(pParse, 0, (void*)pExpr);
+          }
+          goto lookupname_end;
+        }
+      }
+    }
+
+    /* Advance to the next name context.  The loop will exit when either
+    ** we have a match (cnt>0) or when we run out of name contexts.
+    */
+    if( cnt ) break;
+    pNC = pNC->pNext;
+    nSubquery++;
+  }while( pNC );
+
+
+  /*
+  ** If X and Y are NULL (in other words if only the column name Z is
+  ** supplied) and the value of Z is enclosed in double-quotes, then
+  ** Z is a string literal if it doesn't match any column names.  In that
+  ** case, we need to return right away and not make any changes to
+  ** pExpr.
+  **
+  ** Because no reference was made to outer contexts, the pNC->nRef
+  ** fields are not changed in any context.
+  */
+  if( cnt==0 && zTab==0 ){
+    assert( pExpr->op==TK_ID );
+    if( ExprHasProperty(pExpr,EP_DblQuoted)
+     && areDoubleQuotedStringsEnabled(db, pTopNC)
+    ){
+      /* If a double-quoted identifier does not match any known column name,
+      ** then treat it as a string.
+      **
+      ** This hack was added in the early days of SQLite in a misguided attempt
+      ** to be compatible with MySQL 3.x, which used double-quotes for strings.
+      ** I now sorely regret putting in this hack. The effect of this hack is
+      ** that misspelled identifier names are silently converted into strings
+      ** rather than causing an error, to the frustration of countless
+      ** programmers. To all those frustrated programmers, my apologies.
+      **
+      ** Someday, I hope to get rid of this hack. Unfortunately there is
+      ** a huge amount of legacy SQL that uses it. So for now, we just
+      ** issue a warning.
+      */
+      sqlite3_log(SQLITE_WARNING,
+        "double-quoted string literal: \"%w\"", zCol);
+#ifdef SQLITE_ENABLE_NORMALIZE
+      sqlite3VdbeAddDblquoteStr(db, pParse->pVdbe, zCol);
+#endif
+      pExpr->op = TK_STRING;
+      memset(&pExpr->y, 0, sizeof(pExpr->y));
+      return WRC_Prune;
+    }
+    if( sqlite3ExprIdToTrueFalse(pExpr) ){
+      return WRC_Prune;
+    }
+  }
+
+  /*
+  ** cnt==0 means there was not match.
+  ** cnt>1 means there were two or more matches.
+  **
+  ** cnt==0 is always an error.  cnt>1 is often an error, but might
+  ** be multiple matches for a NATURAL LEFT JOIN or a LEFT JOIN USING.
+  */
+  assert( pFJMatch==0 || cnt>0 );
+  assert( !ExprHasProperty(pExpr, EP_xIsSelect|EP_IntValue) );
+  if( cnt!=1 ){
+    const char *zErr;
+    if( pFJMatch ){
+      if( pFJMatch->nExpr==cnt-1 ){
+        if( ExprHasProperty(pExpr,EP_Leaf) ){
+          ExprClearProperty(pExpr,EP_Leaf);
+        }else{
+          sqlite3ExprDelete(db, pExpr->pLeft);
+          pExpr->pLeft = 0;
+          sqlite3ExprDelete(db, pExpr->pRight);
+          pExpr->pRight = 0;
+        }
+        extendFJMatch(pParse, &pFJMatch, pMatch, pExpr->iColumn);
+        pExpr->op = TK_FUNCTION;
+        pExpr->u.zToken = "coalesce";
+        pExpr->x.pList = pFJMatch;
+        cnt = 1;
+        goto lookupname_end;
+      }else{
+        sqlite3ExprListDelete(db, pFJMatch);
+        pFJMatch = 0;
+      }
+    }
+    zErr = cnt==0 ? "no such column" : "ambiguous column name";
+    if( zDb ){
+      sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol);
+    }else if( zTab ){
+      sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol);
+    }else if( cnt==0 && ExprHasProperty(pRight,EP_DblQuoted) ){
+      sqlite3ErrorMsg(pParse, "%s: \"%s\" - should this be a"
+                              " string literal in single-quotes?",
+                              zErr, zCol);
+    }else{
+      sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
+    }
+    sqlite3RecordErrorOffsetOfExpr(pParse->db, pExpr);
+    pParse->checkSchema = 1;
+    pTopNC->nNcErr++;
+    eNewExprOp = TK_NULL;
+  }
+  assert( pFJMatch==0 );
+
+  /* Remove all substructure from pExpr */
+  if( !ExprHasProperty(pExpr,(EP_TokenOnly|EP_Leaf)) ){
+    sqlite3ExprDelete(db, pExpr->pLeft);
+    pExpr->pLeft = 0;
+    sqlite3ExprDelete(db, pExpr->pRight);
+    pExpr->pRight = 0;
+    ExprSetProperty(pExpr, EP_Leaf);
+  }
+
+  /* If a column from a table in pSrcList is referenced, then record
+  ** this fact in the pSrcList.a[].colUsed bitmask.  Column 0 causes
+  ** bit 0 to be set.  Column 1 sets bit 1.  And so forth.  Bit 63 is
+  ** set if the 63rd or any subsequent column is used.
+  **
+  ** The colUsed mask is an optimization used to help determine if an
+  ** index is a covering index.  The correct answer is still obtained
+  ** if the mask contains extra set bits.  However, it is important to
+  ** avoid setting bits beyond the maximum column number of the table.
+  ** (See ticket [b92e5e8ec2cdbaa1]).
+  **
+  ** If a generated column is referenced, set bits for every column
+  ** of the table.
+  */
+  if( pMatch ){
+    if( pExpr->iColumn>=0 ){
+      pMatch->colUsed |= sqlite3ExprColUsed(pExpr);
+    }else{
+      pMatch->fg.rowidUsed = 1;
+    }
+  }
+
+  pExpr->op = eNewExprOp;
+lookupname_end:
+  if( cnt==1 ){
+    assert( pNC!=0 );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    if( pParse->db->xAuth
+     && (pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER)
+    ){
+      sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
+    }
+#endif
+    /* Increment the nRef value on all name contexts from TopNC up to
+    ** the point where the name matched. */
+    for(;;){
+      assert( pTopNC!=0 );
+      pTopNC->nRef++;
+      if( pTopNC==pNC ) break;
+      pTopNC = pTopNC->pNext;
+    }
+    return WRC_Prune;
+  } else {
+    return WRC_Abort;
+  }
+}
+
+/*
+** Allocate and return a pointer to an expression to load the column iCol
+** from datasource iSrc in SrcList pSrc.
+*/
+SQLITE_PRIVATE Expr *sqlite3CreateColumnExpr(sqlite3 *db, SrcList *pSrc, int iSrc, int iCol){
+  Expr *p = sqlite3ExprAlloc(db, TK_COLUMN, 0, 0);
+  if( p ){
+    SrcItem *pItem = &pSrc->a[iSrc];
+    Table *pTab;
+    assert( ExprUseYTab(p) );
+    pTab = p->y.pTab = pItem->pSTab;
+    p->iTable = pItem->iCursor;
+    if( p->y.pTab->iPKey==iCol ){
+      p->iColumn = -1;
+    }else{
+      p->iColumn = (ynVar)iCol;
+      if( (pTab->tabFlags & TF_HasGenerated)!=0
+       && (pTab->aCol[iCol].colFlags & COLFLAG_GENERATED)!=0
+      ){
+        testcase( pTab->nCol==63 );
+        testcase( pTab->nCol==64 );
+        pItem->colUsed = pTab->nCol>=64 ? ALLBITS : MASKBIT(pTab->nCol)-1;
+      }else{
+        testcase( iCol==BMS );
+        testcase( iCol==BMS-1 );
+        pItem->colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol);
+      }
+    }
+  }
+  return p;
+}
+
+/*
+** Report an error that an expression is not valid for some set of
+** pNC->ncFlags values determined by validMask.
+**
+** static void notValid(
+**   Parse *pParse,       // Leave error message here
+**   NameContext *pNC,    // The name context
+**   const char *zMsg,    // Type of error
+**   int validMask,       // Set of contexts for which prohibited
+**   Expr *pExpr          // Invalidate this expression on error
+** ){...}
+**
+** As an optimization, since the conditional is almost always false
+** (because errors are rare), the conditional is moved outside of the
+** function call using a macro.
+*/
+static void notValidImpl(
+   Parse *pParse,       /* Leave error message here */
+   NameContext *pNC,    /* The name context */
+   const char *zMsg,    /* Type of error */
+   Expr *pExpr,         /* Invalidate this expression on error */
+   Expr *pError         /* Associate error with this expression */
+){
+  const char *zIn = "partial index WHERE clauses";
+  if( pNC->ncFlags & NC_IdxExpr )      zIn = "index expressions";
+#ifndef SQLITE_OMIT_CHECK
+  else if( pNC->ncFlags & NC_IsCheck ) zIn = "CHECK constraints";
+#endif
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  else if( pNC->ncFlags & NC_GenCol ) zIn = "generated columns";
+#endif
+  sqlite3ErrorMsg(pParse, "%s prohibited in %s", zMsg, zIn);
+  if( pExpr ) pExpr->op = TK_NULL;
+  sqlite3RecordErrorOffsetOfExpr(pParse->db, pError);
+}
+#define sqlite3ResolveNotValid(P,N,M,X,E,R) \
+  assert( ((X)&~(NC_IsCheck|NC_PartIdx|NC_IdxExpr|NC_GenCol))==0 ); \
+  if( ((N)->ncFlags & (X))!=0 ) notValidImpl(P,N,M,E,R);
+
+/*
+** Expression p should encode a floating point value between 1.0 and 0.0.
+** Return 1024 times this value.  Or return -1 if p is not a floating point
+** value between 1.0 and 0.0.
+*/
+static int exprProbability(Expr *p){
+  double r = -1.0;
+  if( p->op!=TK_FLOAT ) return -1;
+  assert( !ExprHasProperty(p, EP_IntValue) );
+  sqlite3AtoF(p->u.zToken, &r, sqlite3Strlen30(p->u.zToken), SQLITE_UTF8);
+  assert( r>=0.0 );
+  if( r>1.0 ) return -1;
+  return (int)(r*134217728.0);
+}
+
+/*
+** This routine is callback for sqlite3WalkExpr().
+**
+** Resolve symbolic names into TK_COLUMN operators for the current
+** node in the expression tree.  Return 0 to continue the search down
+** the tree or 2 to abort the tree walk.
+**
+** This routine also does error checking and name resolution for
+** function names.  The operator for aggregate functions is changed
+** to TK_AGG_FUNCTION.
+*/
+static int resolveExprStep(Walker *pWalker, Expr *pExpr){
+  NameContext *pNC;
+  Parse *pParse;
+
+  pNC = pWalker->u.pNC;
+  assert( pNC!=0 );
+  pParse = pNC->pParse;
+  assert( pParse==pWalker->pParse );
+
+#ifndef NDEBUG
+  if( pNC->pSrcList && pNC->pSrcList->nAlloc>0 ){
+    SrcList *pSrcList = pNC->pSrcList;
+    int i;
+    for(i=0; i<pNC->pSrcList->nSrc; i++){
+      assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
+    }
+  }
+#endif
+  switch( pExpr->op ){
+
+    /* The special operator TK_ROW means use the rowid for the first
+    ** column in the FROM clause.  This is used by the LIMIT and ORDER BY
+    ** clause processing on UPDATE and DELETE statements, and by
+    ** UPDATE ... FROM statement processing.
+    */
+    case TK_ROW: {
+      SrcList *pSrcList = pNC->pSrcList;
+      SrcItem *pItem;
+      assert( pSrcList && pSrcList->nSrc>=1 );
+      pItem = pSrcList->a;
+      pExpr->op = TK_COLUMN;
+      assert( ExprUseYTab(pExpr) );
+      pExpr->y.pTab = pItem->pSTab;
+      pExpr->iTable = pItem->iCursor;
+      pExpr->iColumn--;
+      pExpr->affExpr = SQLITE_AFF_INTEGER;
+      break;
+    }
+
+    /* An optimization:  Attempt to convert
+    **
+    **      "expr IS NOT NULL"  -->  "TRUE"
+    **      "expr IS NULL"      -->  "FALSE"
+    **
+    ** if we can prove that "expr" is never NULL.  Call this the
+    ** "NOT NULL strength reduction optimization".
+    **
+    ** If this optimization occurs, also restore the NameContext ref-counts
+    ** to the state they where in before the "column" LHS expression was
+    ** resolved.  This prevents "column" from being counted as having been
+    ** referenced, which might prevent a SELECT from being erroneously
+    ** marked as correlated.
+    **
+    ** 2024-03-28: Beware of aggregates.  A bare column of aggregated table
+    ** can still evaluate to NULL even though it is marked as NOT NULL.
+    ** Example:
+    **
+    **       CREATE TABLE t1(a INT NOT NULL);
+    **       SELECT a, a IS NULL, a IS NOT NULL, count(*) FROM t1;
+    **
+    ** The "a IS NULL" and "a IS NOT NULL" expressions cannot be optimized
+    ** here because at the time this case is hit, we do not yet know whether
+    ** or not t1 is being aggregated.  We have to assume the worst and omit
+    ** the optimization.  The only time it is safe to apply this optimization
+    ** is within the WHERE clause.
+    */
+    case TK_NOTNULL:
+    case TK_ISNULL: {
+      int anRef[8];
+      NameContext *p;
+      int i;
+      for(i=0, p=pNC; p && i<ArraySize(anRef); p=p->pNext, i++){
+        anRef[i] = p->nRef;
+      }
+      sqlite3WalkExpr(pWalker, pExpr->pLeft);
+      if( IN_RENAME_OBJECT ) return WRC_Prune;
+      if( sqlite3ExprCanBeNull(pExpr->pLeft) ){
+        /* The expression can be NULL.  So the optimization does not apply */
+        return WRC_Prune;
+      }
+
+      for(i=0, p=pNC; p; p=p->pNext, i++){
+        if( (p->ncFlags & NC_Where)==0 ){
+          return WRC_Prune;  /* Not in a WHERE clause.  Unsafe to optimize. */
+        }
+      }
+      testcase( ExprHasProperty(pExpr, EP_OuterON) );
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+#if TREETRACE_ENABLED
+      if( sqlite3TreeTrace & 0x80000 ){
+        sqlite3DebugPrintf(
+           "NOT NULL strength reduction converts the following to %d:\n",
+           pExpr->op==TK_NOTNULL
+        );
+        sqlite3ShowExpr(pExpr);
+      }
+#endif /* TREETRACE_ENABLED */
+      pExpr->u.iValue = (pExpr->op==TK_NOTNULL);
+      pExpr->flags |= EP_IntValue;
+      pExpr->op = TK_INTEGER;
+      for(i=0, p=pNC; p && i<ArraySize(anRef); p=p->pNext, i++){
+        p->nRef = anRef[i];
+      }
+      sqlite3ExprDelete(pParse->db, pExpr->pLeft);
+      pExpr->pLeft = 0;
+      return WRC_Prune;
+    }
+
+    /* A column name:                    ID
+    ** Or table name and column name:    ID.ID
+    ** Or a database, table and column:  ID.ID.ID
+    **
+    ** The TK_ID and TK_OUT cases are combined so that there will only
+    ** be one call to lookupName().  Then the compiler will in-line
+    ** lookupName() for a size reduction and performance increase.
+    */
+    case TK_ID:
+    case TK_DOT: {
+      const char *zTable;
+      const char *zDb;
+      Expr *pRight;
+
+      if( pExpr->op==TK_ID ){
+        zDb = 0;
+        zTable = 0;
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        pRight = pExpr;
+      }else{
+        Expr *pLeft = pExpr->pLeft;
+        testcase( pNC->ncFlags & NC_IdxExpr );
+        testcase( pNC->ncFlags & NC_GenCol );
+        sqlite3ResolveNotValid(pParse, pNC, "the \".\" operator",
+                               NC_IdxExpr|NC_GenCol, 0, pExpr);
+        pRight = pExpr->pRight;
+        if( pRight->op==TK_ID ){
+          zDb = 0;
+        }else{
+          assert( pRight->op==TK_DOT );
+          assert( !ExprHasProperty(pRight, EP_IntValue) );
+          zDb = pLeft->u.zToken;
+          pLeft = pRight->pLeft;
+          pRight = pRight->pRight;
+        }
+        assert( ExprUseUToken(pLeft) && ExprUseUToken(pRight) );
+        zTable = pLeft->u.zToken;
+        assert( ExprUseYTab(pExpr) );
+        if( IN_RENAME_OBJECT ){
+          sqlite3RenameTokenRemap(pParse, (void*)pExpr, (void*)pRight);
+          sqlite3RenameTokenRemap(pParse, (void*)&pExpr->y.pTab, (void*)pLeft);
+        }
+      }
+      return lookupName(pParse, zDb, zTable, pRight, pNC, pExpr);
+    }
+
+    /* Resolve function names
+    */
+    case TK_FUNCTION: {
+      ExprList *pList;            /* The argument list */
+      int n;                      /* Number of arguments */
+      int no_such_func = 0;       /* True if no such function exists */
+      int wrong_num_args = 0;     /* True if wrong number of arguments */
+      int is_agg = 0;             /* True if is an aggregate function */
+      const char *zId;            /* The function name. */
+      FuncDef *pDef;              /* Information about the function */
+      u8 enc = ENC(pParse->db);   /* The database encoding */
+      int savedAllowFlags = (pNC->ncFlags & (NC_AllowAgg | NC_AllowWin));
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      Window *pWin = (IsWindowFunc(pExpr) ? pExpr->y.pWin : 0);
+#endif
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect|EP_IntValue) );
+      assert( pExpr->pLeft==0 || pExpr->pLeft->op==TK_ORDER );
+      pList = pExpr->x.pList;
+      n = pList ? pList->nExpr : 0;
+      zId = pExpr->u.zToken;
+      pDef = sqlite3FindFunction(pParse->db, zId, n, enc, 0);
+      if( pDef==0 ){
+        pDef = sqlite3FindFunction(pParse->db, zId, -2, enc, 0);
+        if( pDef==0 ){
+          no_such_func = 1;
+        }else{
+          wrong_num_args = 1;
+        }
+      }else{
+        is_agg = pDef->xFinalize!=0;
+        if( pDef->funcFlags & SQLITE_FUNC_UNLIKELY ){
+          ExprSetProperty(pExpr, EP_Unlikely);
+          if( n==2 ){
+            pExpr->iTable = exprProbability(pList->a[1].pExpr);
+            if( pExpr->iTable<0 ){
+              sqlite3ErrorMsg(pParse,
+                "second argument to %#T() must be a "
+                "constant between 0.0 and 1.0", pExpr);
+              pNC->nNcErr++;
+            }
+          }else{
+            /* EVIDENCE-OF: R-61304-29449 The unlikely(X) function is
+            ** equivalent to likelihood(X, 0.0625).
+            ** EVIDENCE-OF: R-01283-11636 The unlikely(X) function is
+            ** short-hand for likelihood(X,0.0625).
+            ** EVIDENCE-OF: R-36850-34127 The likely(X) function is short-hand
+            ** for likelihood(X,0.9375).
+            ** EVIDENCE-OF: R-53436-40973 The likely(X) function is equivalent
+            ** to likelihood(X,0.9375). */
+            /* TUNING: unlikely() probability is 0.0625.  likely() is 0.9375 */
+            pExpr->iTable = pDef->zName[0]=='u' ? 8388608 : 125829120;
+          }
+        }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+        {
+          int auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0,pDef->zName,0);
+          if( auth!=SQLITE_OK ){
+            if( auth==SQLITE_DENY ){
+              sqlite3ErrorMsg(pParse, "not authorized to use function: %#T",
+                                      pExpr);
+              pNC->nNcErr++;
+            }
+            pExpr->op = TK_NULL;
+            return WRC_Prune;
+          }
+        }
+#endif
+
+        /* If the function may call sqlite3_value_subtype(), then set the
+        ** EP_SubtArg flag on all of its argument expressions. This prevents
+        ** where.c from replacing the expression with a value read from an
+        ** index on the same expression, which will not have the correct
+        ** subtype. Also set the flag if the function expression itself is
+        ** an EP_SubtArg expression. In this case subtypes are required as
+        ** the function may return a value with a subtype back to its
+        ** caller using sqlite3_result_value().  */
+        if( (pDef->funcFlags & SQLITE_SUBTYPE)
+         || ExprHasProperty(pExpr, EP_SubtArg)
+        ){
+          int ii;
+          for(ii=0; ii<n; ii++){
+            ExprSetProperty(pList->a[ii].pExpr, EP_SubtArg);
+          }
+        }
+
+        if( pDef->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG) ){
+          /* For the purposes of the EP_ConstFunc flag, date and time
+          ** functions and other functions that change slowly are considered
+          ** constant because they are constant for the duration of one query.
+          ** This allows them to be factored out of inner loops. */
+          ExprSetProperty(pExpr,EP_ConstFunc);
+        }
+        if( (pDef->funcFlags & SQLITE_FUNC_CONSTANT)==0 ){
+          /* Clearly non-deterministic functions like random(), but also
+          ** date/time functions that use 'now', and other functions like
+          ** sqlite_version() that might change over time cannot be used
+          ** in an index or generated column.  Curiously, they can be used
+          ** in a CHECK constraint.  SQLServer, MySQL, and PostgreSQL all
+          ** all this. */
+          sqlite3ResolveNotValid(pParse, pNC, "non-deterministic functions",
+                                 NC_IdxExpr|NC_PartIdx|NC_GenCol, 0, pExpr);
+        }else{
+          assert( (NC_SelfRef & 0xff)==NC_SelfRef ); /* Must fit in 8 bits */
+          pExpr->op2 = pNC->ncFlags & NC_SelfRef;
+          if( pNC->ncFlags & NC_FromDDL ) ExprSetProperty(pExpr, EP_FromDDL);
+        }
+        if( (pDef->funcFlags & SQLITE_FUNC_INTERNAL)!=0
+         && pParse->nested==0
+         && (pParse->db->mDbFlags & DBFLAG_InternalFunc)==0
+        ){
+          /* Internal-use-only functions are disallowed unless the
+          ** SQL is being compiled using sqlite3NestedParse() or
+          ** the SQLITE_TESTCTRL_INTERNAL_FUNCTIONS test-control has be
+          ** used to activate internal functions for testing purposes */
+          no_such_func = 1;
+          pDef = 0;
+        }else
+        if( (pDef->funcFlags & (SQLITE_FUNC_DIRECT|SQLITE_FUNC_UNSAFE))!=0
+         && !IN_RENAME_OBJECT
+        ){
+          sqlite3ExprFunctionUsable(pParse, pExpr, pDef);
+        }
+      }
+
+      if( 0==IN_RENAME_OBJECT ){
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        assert( is_agg==0 || (pDef->funcFlags & SQLITE_FUNC_MINMAX)
+          || (pDef->xValue==0 && pDef->xInverse==0)
+          || (pDef->xValue && pDef->xInverse && pDef->xSFunc && pDef->xFinalize)
+        );
+        if( pDef && pDef->xValue==0 && pWin ){
+          sqlite3ErrorMsg(pParse,
+              "%#T() may not be used as a window function", pExpr
+          );
+          pNC->nNcErr++;
+        }else if(
+              (is_agg && (pNC->ncFlags & NC_AllowAgg)==0)
+           || (is_agg && (pDef->funcFlags&SQLITE_FUNC_WINDOW) && !pWin)
+           || (is_agg && pWin && (pNC->ncFlags & NC_AllowWin)==0)
+        ){
+          const char *zType;
+          if( (pDef->funcFlags & SQLITE_FUNC_WINDOW) || pWin ){
+            zType = "window";
+          }else{
+            zType = "aggregate";
+          }
+          sqlite3ErrorMsg(pParse, "misuse of %s function %#T()",zType,pExpr);
+          pNC->nNcErr++;
+          is_agg = 0;
+        }
+#else
+        if( (is_agg && (pNC->ncFlags & NC_AllowAgg)==0) ){
+          sqlite3ErrorMsg(pParse,"misuse of aggregate function %#T()",pExpr);
+          pNC->nNcErr++;
+          is_agg = 0;
+        }
+#endif
+        else if( no_such_func && pParse->db->init.busy==0
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+                  && pParse->explain==0
+#endif
+        ){
+          sqlite3ErrorMsg(pParse, "no such function: %#T", pExpr);
+          pNC->nNcErr++;
+        }else if( wrong_num_args ){
+          sqlite3ErrorMsg(pParse,"wrong number of arguments to function %#T()",
+               pExpr);
+          pNC->nNcErr++;
+        }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        else if( is_agg==0 && ExprHasProperty(pExpr, EP_WinFunc) ){
+          sqlite3ErrorMsg(pParse,
+              "FILTER may not be used with non-aggregate %#T()",
+              pExpr
+          );
+          pNC->nNcErr++;
+        }
+#endif
+        else if( is_agg==0 && pExpr->pLeft ){
+          sqlite3ExprOrderByAggregateError(pParse, pExpr);
+          pNC->nNcErr++;
+        }
+        if( is_agg ){
+          /* Window functions may not be arguments of aggregate functions.
+          ** Or arguments of other window functions. But aggregate functions
+          ** may be arguments for window functions.  */
+#ifndef SQLITE_OMIT_WINDOWFUNC
+          pNC->ncFlags &= ~(NC_AllowWin | (!pWin ? NC_AllowAgg : 0));
+#else
+          pNC->ncFlags &= ~NC_AllowAgg;
+#endif
+        }
+      }
+      else if( ExprHasProperty(pExpr, EP_WinFunc) || pExpr->pLeft ){
+        is_agg = 1;
+      }
+      sqlite3WalkExprList(pWalker, pList);
+      if( is_agg ){
+        if( pExpr->pLeft ){
+          assert( pExpr->pLeft->op==TK_ORDER );
+          assert( ExprUseXList(pExpr->pLeft) );
+          sqlite3WalkExprList(pWalker, pExpr->pLeft->x.pList);
+        }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        if( pWin && pParse->nErr==0 ){
+          Select *pSel = pNC->pWinSelect;
+          assert( ExprUseYWin(pExpr) && pWin==pExpr->y.pWin );
+          if( IN_RENAME_OBJECT==0 ){
+            sqlite3WindowUpdate(pParse, pSel ? pSel->pWinDefn : 0, pWin, pDef);
+            if( pParse->db->mallocFailed ) break;
+          }
+          sqlite3WalkExprList(pWalker, pWin->pPartition);
+          sqlite3WalkExprList(pWalker, pWin->pOrderBy);
+          sqlite3WalkExpr(pWalker, pWin->pFilter);
+          sqlite3WindowLink(pSel, pWin);
+          pNC->ncFlags |= NC_HasWin;
+        }else
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+        {
+          NameContext *pNC2;          /* For looping up thru outer contexts */
+          pExpr->op = TK_AGG_FUNCTION;
+          pExpr->op2 = 0;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+          if( ExprHasProperty(pExpr, EP_WinFunc) ){
+            sqlite3WalkExpr(pWalker, pExpr->y.pWin->pFilter);
+          }
+#endif
+          pNC2 = pNC;
+          while( pNC2
+              && sqlite3ReferencesSrcList(pParse, pExpr, pNC2->pSrcList)==0
+          ){
+            pExpr->op2 += (1 + pNC2->nNestedSelect);
+            pNC2 = pNC2->pNext;
+          }
+          assert( pDef!=0 || IN_RENAME_OBJECT );
+          if( pNC2 && pDef ){
+            pExpr->op2 += pNC2->nNestedSelect;
+            assert( SQLITE_FUNC_MINMAX==NC_MinMaxAgg );
+            assert( SQLITE_FUNC_ANYORDER==NC_OrderAgg );
+            testcase( (pDef->funcFlags & SQLITE_FUNC_MINMAX)!=0 );
+            testcase( (pDef->funcFlags & SQLITE_FUNC_ANYORDER)!=0 );
+            pNC2->ncFlags |= NC_HasAgg
+              | ((pDef->funcFlags^SQLITE_FUNC_ANYORDER)
+                  & (SQLITE_FUNC_MINMAX|SQLITE_FUNC_ANYORDER));
+          }
+        }
+        pNC->ncFlags |= savedAllowFlags;
+      }
+      /* FIX ME:  Compute pExpr->affinity based on the expected return
+      ** type of the function
+      */
+      return WRC_Prune;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_SELECT:
+    case TK_EXISTS:  testcase( pExpr->op==TK_EXISTS );
+#endif
+    case TK_IN: {
+      testcase( pExpr->op==TK_IN );
+      if( ExprUseXSelect(pExpr) ){
+        int nRef = pNC->nRef;
+        testcase( pNC->ncFlags & NC_IsCheck );
+        testcase( pNC->ncFlags & NC_PartIdx );
+        testcase( pNC->ncFlags & NC_IdxExpr );
+        testcase( pNC->ncFlags & NC_GenCol );
+        assert( pExpr->x.pSelect );
+        if( pNC->ncFlags & NC_SelfRef ){
+          notValidImpl(pParse, pNC, "subqueries", pExpr, pExpr);
+        }else{
+          sqlite3WalkSelect(pWalker, pExpr->x.pSelect);
+        }
+        assert( pNC->nRef>=nRef );
+        if( nRef!=pNC->nRef ){
+          ExprSetProperty(pExpr, EP_VarSelect);
+          pExpr->x.pSelect->selFlags |= SF_Correlated;
+        }
+        pNC->ncFlags |= NC_Subquery;
+      }
+      break;
+    }
+    case TK_VARIABLE: {
+      testcase( pNC->ncFlags & NC_IsCheck );
+      testcase( pNC->ncFlags & NC_PartIdx );
+      testcase( pNC->ncFlags & NC_IdxExpr );
+      testcase( pNC->ncFlags & NC_GenCol );
+      sqlite3ResolveNotValid(pParse, pNC, "parameters",
+               NC_IsCheck|NC_PartIdx|NC_IdxExpr|NC_GenCol, pExpr, pExpr);
+      break;
+    }
+    case TK_IS:
+    case TK_ISNOT: {
+      Expr *pRight = sqlite3ExprSkipCollateAndLikely(pExpr->pRight);
+      assert( !ExprHasProperty(pExpr, EP_Reduced) );
+      /* Handle special cases of "x IS TRUE", "x IS FALSE", "x IS NOT TRUE",
+      ** and "x IS NOT FALSE". */
+      if( ALWAYS(pRight) && (pRight->op==TK_ID || pRight->op==TK_TRUEFALSE) ){
+        int rc = resolveExprStep(pWalker, pRight);
+        if( rc==WRC_Abort ) return WRC_Abort;
+        if( pRight->op==TK_TRUEFALSE ){
+          pExpr->op2 = pExpr->op;
+          pExpr->op = TK_TRUTH;
+          return WRC_Continue;
+        }
+      }
+      /* no break */ deliberate_fall_through
+    }
+    case TK_BETWEEN:
+    case TK_EQ:
+    case TK_NE:
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE: {
+      int nLeft, nRight;
+      if( pParse->db->mallocFailed ) break;
+      assert( pExpr->pLeft!=0 );
+      nLeft = sqlite3ExprVectorSize(pExpr->pLeft);
+      if( pExpr->op==TK_BETWEEN ){
+        assert( ExprUseXList(pExpr) );
+        nRight = sqlite3ExprVectorSize(pExpr->x.pList->a[0].pExpr);
+        if( nRight==nLeft ){
+          nRight = sqlite3ExprVectorSize(pExpr->x.pList->a[1].pExpr);
+        }
+      }else{
+        assert( pExpr->pRight!=0 );
+        nRight = sqlite3ExprVectorSize(pExpr->pRight);
+      }
+      if( nLeft!=nRight ){
+        testcase( pExpr->op==TK_EQ );
+        testcase( pExpr->op==TK_NE );
+        testcase( pExpr->op==TK_LT );
+        testcase( pExpr->op==TK_LE );
+        testcase( pExpr->op==TK_GT );
+        testcase( pExpr->op==TK_GE );
+        testcase( pExpr->op==TK_IS );
+        testcase( pExpr->op==TK_ISNOT );
+        testcase( pExpr->op==TK_BETWEEN );
+        sqlite3ErrorMsg(pParse, "row value misused");
+        sqlite3RecordErrorOffsetOfExpr(pParse->db, pExpr);
+      }
+      break;
+    }
+  }
+  assert( pParse->db->mallocFailed==0 || pParse->nErr!=0 );
+  return pParse->nErr ? WRC_Abort : WRC_Continue;
+}
+
+/*
+** pEList is a list of expressions which are really the result set of the
+** a SELECT statement.  pE is a term in an ORDER BY or GROUP BY clause.
+** This routine checks to see if pE is a simple identifier which corresponds
+** to the AS-name of one of the terms of the expression list.  If it is,
+** this routine return an integer between 1 and N where N is the number of
+** elements in pEList, corresponding to the matching entry.  If there is
+** no match, or if pE is not a simple identifier, then this routine
+** return 0.
+**
+** pEList has been resolved.  pE has not.
+*/
+static int resolveAsName(
+  Parse *pParse,     /* Parsing context for error messages */
+  ExprList *pEList,  /* List of expressions to scan */
+  Expr *pE           /* Expression we are trying to match */
+){
+  int i;             /* Loop counter */
+
+  UNUSED_PARAMETER(pParse);
+
+  if( pE->op==TK_ID ){
+    const char *zCol;
+    assert( !ExprHasProperty(pE, EP_IntValue) );
+    zCol = pE->u.zToken;
+    for(i=0; i<pEList->nExpr; i++){
+      if( pEList->a[i].fg.eEName==ENAME_NAME
+       && sqlite3_stricmp(pEList->a[i].zEName, zCol)==0
+      ){
+        return i+1;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** pE is a pointer to an expression which is a single term in the
+** ORDER BY of a compound SELECT.  The expression has not been
+** name resolved.
+**
+** At the point this routine is called, we already know that the
+** ORDER BY term is not an integer index into the result set.  That
+** case is handled by the calling routine.
+**
+** Attempt to match pE against result set columns in the left-most
+** SELECT statement.  Return the index i of the matching column,
+** as an indication to the caller that it should sort by the i-th column.
+** The left-most column is 1.  In other words, the value returned is the
+** same integer value that would be used in the SQL statement to indicate
+** the column.
+**
+** If there is no match, return 0.  Return -1 if an error occurs.
+*/
+static int resolveOrderByTermToExprList(
+  Parse *pParse,     /* Parsing context for error messages */
+  Select *pSelect,   /* The SELECT statement with the ORDER BY clause */
+  Expr *pE           /* The specific ORDER BY term */
+){
+  int i;             /* Loop counter */
+  ExprList *pEList;  /* The columns of the result set */
+  NameContext nc;    /* Name context for resolving pE */
+  sqlite3 *db;       /* Database connection */
+  int rc;            /* Return code from subprocedures */
+  u8 savedSuppErr;   /* Saved value of db->suppressErr */
+
+  assert( sqlite3ExprIsInteger(pE, &i, 0)==0 );
+  pEList = pSelect->pEList;
+
+  /* Resolve all names in the ORDER BY term expression
+  */
+  memset(&nc, 0, sizeof(nc));
+  nc.pParse = pParse;
+  nc.pSrcList = pSelect->pSrc;
+  nc.uNC.pEList = pEList;
+  nc.ncFlags = NC_AllowAgg|NC_UEList|NC_NoSelect;
+  nc.nNcErr = 0;
+  db = pParse->db;
+  savedSuppErr = db->suppressErr;
+  db->suppressErr = 1;
+  rc = sqlite3ResolveExprNames(&nc, pE);
+  db->suppressErr = savedSuppErr;
+  if( rc ) return 0;
+
+  /* Try to match the ORDER BY expression against an expression
+  ** in the result set.  Return an 1-based index of the matching
+  ** result-set entry.
+  */
+  for(i=0; i<pEList->nExpr; i++){
+    if( sqlite3ExprCompare(0, pEList->a[i].pExpr, pE, -1)<2 ){
+      return i+1;
+    }
+  }
+
+  /* If no match, return 0. */
+  return 0;
+}
+
+/*
+** Generate an ORDER BY or GROUP BY term out-of-range error.
+*/
+static void resolveOutOfRangeError(
+  Parse *pParse,         /* The error context into which to write the error */
+  const char *zType,     /* "ORDER" or "GROUP" */
+  int i,                 /* The index (1-based) of the term out of range */
+  int mx,                /* Largest permissible value of i */
+  Expr *pError           /* Associate the error with the expression */
+){
+  sqlite3ErrorMsg(pParse,
+    "%r %s BY term out of range - should be "
+    "between 1 and %d", i, zType, mx);
+  sqlite3RecordErrorOffsetOfExpr(pParse->db, pError);
+}
+
+/*
+** Analyze the ORDER BY clause in a compound SELECT statement.   Modify
+** each term of the ORDER BY clause is a constant integer between 1
+** and N where N is the number of columns in the compound SELECT.
+**
+** ORDER BY terms that are already an integer between 1 and N are
+** unmodified.  ORDER BY terms that are integers outside the range of
+** 1 through N generate an error.  ORDER BY terms that are expressions
+** are matched against result set expressions of compound SELECT
+** beginning with the left-most SELECT and working toward the right.
+** At the first match, the ORDER BY expression is transformed into
+** the integer column number.
+**
+** Return the number of errors seen.
+*/
+static int resolveCompoundOrderBy(
+  Parse *pParse,        /* Parsing context.  Leave error messages here */
+  Select *pSelect       /* The SELECT statement containing the ORDER BY */
+){
+  int i;
+  ExprList *pOrderBy;
+  ExprList *pEList;
+  sqlite3 *db;
+  int moreToDo = 1;
+
+  pOrderBy = pSelect->pOrderBy;
+  if( pOrderBy==0 ) return 0;
+  db = pParse->db;
+  if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many terms in ORDER BY clause");
+    return 1;
+  }
+  for(i=0; i<pOrderBy->nExpr; i++){
+    pOrderBy->a[i].fg.done = 0;
+  }
+  pSelect->pNext = 0;
+  while( pSelect->pPrior ){
+    pSelect->pPrior->pNext = pSelect;
+    pSelect = pSelect->pPrior;
+  }
+  while( pSelect && moreToDo ){
+    struct ExprList_item *pItem;
+    moreToDo = 0;
+    pEList = pSelect->pEList;
+    assert( pEList!=0 );
+    for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
+      int iCol = -1;
+      Expr *pE, *pDup;
+      if( pItem->fg.done ) continue;
+      pE = sqlite3ExprSkipCollateAndLikely(pItem->pExpr);
+      if( NEVER(pE==0) ) continue;
+      if( sqlite3ExprIsInteger(pE, &iCol, 0) ){
+        if( iCol<=0 || iCol>pEList->nExpr ){
+          resolveOutOfRangeError(pParse, "ORDER", i+1, pEList->nExpr, pE);
+          return 1;
+        }
+      }else{
+        iCol = resolveAsName(pParse, pEList, pE);
+        if( iCol==0 ){
+          /* Now test if expression pE matches one of the values returned
+          ** by pSelect. In the usual case this is done by duplicating the
+          ** expression, resolving any symbols in it, and then comparing
+          ** it against each expression returned by the SELECT statement.
+          ** Once the comparisons are finished, the duplicate expression
+          ** is deleted.
+          **
+          ** If this is running as part of an ALTER TABLE operation and
+          ** the symbols resolve successfully, also resolve the symbols in the
+          ** actual expression. This allows the code in alter.c to modify
+          ** column references within the ORDER BY expression as required.  */
+          pDup = sqlite3ExprDup(db, pE, 0);
+          if( !db->mallocFailed ){
+            assert(pDup);
+            iCol = resolveOrderByTermToExprList(pParse, pSelect, pDup);
+            if( IN_RENAME_OBJECT && iCol>0 ){
+              resolveOrderByTermToExprList(pParse, pSelect, pE);
+            }
+          }
+          sqlite3ExprDelete(db, pDup);
+        }
+      }
+      if( iCol>0 ){
+        /* Convert the ORDER BY term into an integer column number iCol,
+        ** taking care to preserve the COLLATE clause if it exists. */
+        if( !IN_RENAME_OBJECT ){
+          Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
+          if( pNew==0 ) return 1;
+          pNew->flags |= EP_IntValue;
+          pNew->u.iValue = iCol;
+          if( pItem->pExpr==pE ){
+            pItem->pExpr = pNew;
+          }else{
+            Expr *pParent = pItem->pExpr;
+            assert( pParent->op==TK_COLLATE );
+            while( pParent->pLeft->op==TK_COLLATE ) pParent = pParent->pLeft;
+            assert( pParent->pLeft==pE );
+            pParent->pLeft = pNew;
+          }
+          sqlite3ExprDelete(db, pE);
+          pItem->u.x.iOrderByCol = (u16)iCol;
+        }
+        pItem->fg.done = 1;
+      }else{
+        moreToDo = 1;
+      }
+    }
+    pSelect = pSelect->pNext;
+  }
+  for(i=0; i<pOrderBy->nExpr; i++){
+    if( pOrderBy->a[i].fg.done==0 ){
+      sqlite3ErrorMsg(pParse, "%r ORDER BY term does not match any "
+            "column in the result set", i+1);
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Check every term in the ORDER BY or GROUP BY clause pOrderBy of
+** the SELECT statement pSelect.  If any term is reference to a
+** result set expression (as determined by the ExprList.a.u.x.iOrderByCol
+** field) then convert that term into a copy of the corresponding result set
+** column.
+**
+** If any errors are detected, add an error message to pParse and
+** return non-zero.  Return zero if no errors are seen.
+*/
+SQLITE_PRIVATE int sqlite3ResolveOrderGroupBy(
+  Parse *pParse,        /* Parsing context.  Leave error messages here */
+  Select *pSelect,      /* The SELECT statement containing the clause */
+  ExprList *pOrderBy,   /* The ORDER BY or GROUP BY clause to be processed */
+  const char *zType     /* "ORDER" or "GROUP" */
+){
+  int i;
+  sqlite3 *db = pParse->db;
+  ExprList *pEList;
+  struct ExprList_item *pItem;
+
+  if( pOrderBy==0 || pParse->db->mallocFailed || IN_RENAME_OBJECT ) return 0;
+  if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
+    return 1;
+  }
+  pEList = pSelect->pEList;
+  assert( pEList!=0 );  /* sqlite3SelectNew() guarantees this */
+  for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
+    if( pItem->u.x.iOrderByCol ){
+      if( pItem->u.x.iOrderByCol>pEList->nExpr ){
+        resolveOutOfRangeError(pParse, zType, i+1, pEList->nExpr, 0);
+        return 1;
+      }
+      resolveAlias(pParse, pEList, pItem->u.x.iOrderByCol-1, pItem->pExpr,0);
+    }
+  }
+  return 0;
+}
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Walker callback for windowRemoveExprFromSelect().
+*/
+static int resolveRemoveWindowsCb(Walker *pWalker, Expr *pExpr){
+  UNUSED_PARAMETER(pWalker);
+  if( ExprHasProperty(pExpr, EP_WinFunc) ){
+    Window *pWin = pExpr->y.pWin;
+    sqlite3WindowUnlinkFromSelect(pWin);
+  }
+  return WRC_Continue;
+}
+
+/*
+** Remove any Window objects owned by the expression pExpr from the
+** Select.pWin list of Select object pSelect.
+*/
+static void windowRemoveExprFromSelect(Select *pSelect, Expr *pExpr){
+  if( pSelect->pWin ){
+    Walker sWalker;
+    memset(&sWalker, 0, sizeof(Walker));
+    sWalker.xExprCallback = resolveRemoveWindowsCb;
+    sWalker.u.pSelect = pSelect;
+    sqlite3WalkExpr(&sWalker, pExpr);
+  }
+}
+#else
+# define windowRemoveExprFromSelect(a, b)
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** pOrderBy is an ORDER BY or GROUP BY clause in SELECT statement pSelect.
+** The Name context of the SELECT statement is pNC.  zType is either
+** "ORDER" or "GROUP" depending on which type of clause pOrderBy is.
+**
+** This routine resolves each term of the clause into an expression.
+** If the order-by term is an integer I between 1 and N (where N is the
+** number of columns in the result set of the SELECT) then the expression
+** in the resolution is a copy of the I-th result-set expression.  If
+** the order-by term is an identifier that corresponds to the AS-name of
+** a result-set expression, then the term resolves to a copy of the
+** result-set expression.  Otherwise, the expression is resolved in
+** the usual way - using sqlite3ResolveExprNames().
+**
+** This routine returns the number of errors.  If errors occur, then
+** an appropriate error message might be left in pParse.  (OOM errors
+** excepted.)
+*/
+static int resolveOrderGroupBy(
+  NameContext *pNC,     /* The name context of the SELECT statement */
+  Select *pSelect,      /* The SELECT statement holding pOrderBy */
+  ExprList *pOrderBy,   /* An ORDER BY or GROUP BY clause to resolve */
+  const char *zType     /* Either "ORDER" or "GROUP", as appropriate */
+){
+  int i, j;                      /* Loop counters */
+  int iCol;                      /* Column number */
+  struct ExprList_item *pItem;   /* A term of the ORDER BY clause */
+  Parse *pParse;                 /* Parsing context */
+  int nResult;                   /* Number of terms in the result set */
+
+  assert( pOrderBy!=0 );
+  nResult = pSelect->pEList->nExpr;
+  pParse = pNC->pParse;
+  for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
+    Expr *pE = pItem->pExpr;
+    Expr *pE2 = sqlite3ExprSkipCollateAndLikely(pE);
+    if( NEVER(pE2==0) ) continue;
+    if( zType[0]!='G' ){
+      iCol = resolveAsName(pParse, pSelect->pEList, pE2);
+      if( iCol>0 ){
+        /* If an AS-name match is found, mark this ORDER BY column as being
+        ** a copy of the iCol-th result-set column.  The subsequent call to
+        ** sqlite3ResolveOrderGroupBy() will convert the expression to a
+        ** copy of the iCol-th result-set expression. */
+        pItem->u.x.iOrderByCol = (u16)iCol;
+        continue;
+      }
+    }
+    if( sqlite3ExprIsInteger(pE2, &iCol, 0) ){
+      /* The ORDER BY term is an integer constant.  Again, set the column
+      ** number so that sqlite3ResolveOrderGroupBy() will convert the
+      ** order-by term to a copy of the result-set expression */
+      if( iCol<1 || iCol>0xffff ){
+        resolveOutOfRangeError(pParse, zType, i+1, nResult, pE2);
+        return 1;
+      }
+      pItem->u.x.iOrderByCol = (u16)iCol;
+      continue;
+    }
+
+    /* Otherwise, treat the ORDER BY term as an ordinary expression */
+    pItem->u.x.iOrderByCol = 0;
+    if( sqlite3ResolveExprNames(pNC, pE) ){
+      return 1;
+    }
+    for(j=0; j<pSelect->pEList->nExpr; j++){
+      if( sqlite3ExprCompare(0, pE, pSelect->pEList->a[j].pExpr, -1)==0 ){
+        /* Since this expression is being changed into a reference
+        ** to an identical expression in the result set, remove all Window
+        ** objects belonging to the expression from the Select.pWin list. */
+        windowRemoveExprFromSelect(pSelect, pE);
+        pItem->u.x.iOrderByCol = j+1;
+      }
+    }
+  }
+  return sqlite3ResolveOrderGroupBy(pParse, pSelect, pOrderBy, zType);
+}
+
+/*
+** Resolve names in the SELECT statement p and all of its descendants.
+*/
+static int resolveSelectStep(Walker *pWalker, Select *p){
+  NameContext *pOuterNC;  /* Context that contains this SELECT */
+  NameContext sNC;        /* Name context of this SELECT */
+  int isCompound;         /* True if p is a compound select */
+  int nCompound;          /* Number of compound terms processed so far */
+  Parse *pParse;          /* Parsing context */
+  int i;                  /* Loop counter */
+  ExprList *pGroupBy;     /* The GROUP BY clause */
+  Select *pLeftmost;      /* Left-most of SELECT of a compound */
+  sqlite3 *db;            /* Database connection */
+
+
+  assert( p!=0 );
+  if( p->selFlags & SF_Resolved ){
+    return WRC_Prune;
+  }
+  pOuterNC = pWalker->u.pNC;
+  pParse = pWalker->pParse;
+  db = pParse->db;
+
+  /* Normally sqlite3SelectExpand() will be called first and will have
+  ** already expanded this SELECT.  However, if this is a subquery within
+  ** an expression, sqlite3ResolveExprNames() will be called without a
+  ** prior call to sqlite3SelectExpand().  When that happens, let
+  ** sqlite3SelectPrep() do all of the processing for this SELECT.
+  ** sqlite3SelectPrep() will invoke both sqlite3SelectExpand() and
+  ** this routine in the correct order.
+  */
+  if( (p->selFlags & SF_Expanded)==0 ){
+    sqlite3SelectPrep(pParse, p, pOuterNC);
+    return pParse->nErr ? WRC_Abort : WRC_Prune;
+  }
+
+  isCompound = p->pPrior!=0;
+  nCompound = 0;
+  pLeftmost = p;
+  while( p ){
+    assert( (p->selFlags & SF_Expanded)!=0 );
+    assert( (p->selFlags & SF_Resolved)==0 );
+    p->selFlags |= SF_Resolved;
+
+    /* Resolve the expressions in the LIMIT and OFFSET clauses. These
+    ** are not allowed to refer to any names, so pass an empty NameContext.
+    */
+    memset(&sNC, 0, sizeof(sNC));
+    sNC.pParse = pParse;
+    sNC.pWinSelect = p;
+    if( sqlite3ResolveExprNames(&sNC, p->pLimit) ){
+      return WRC_Abort;
+    }
+
+    /* If the SF_Converted flags is set, then this Select object was
+    ** was created by the convertCompoundSelectToSubquery() function.
+    ** In this case the ORDER BY clause (p->pOrderBy) should be resolved
+    ** as if it were part of the sub-query, not the parent. This block
+    ** moves the pOrderBy down to the sub-query. It will be moved back
+    ** after the names have been resolved.  */
+    if( p->selFlags & SF_Converted ){
+      Select *pSub;
+      assert( p->pSrc->a[0].fg.isSubquery );
+      assert( p->pSrc->a[0].u4.pSubq!=0 );
+      pSub = p->pSrc->a[0].u4.pSubq->pSelect;
+      assert( pSub!=0 );
+      assert( p->pSrc->nSrc==1 && p->pOrderBy );
+      assert( pSub->pPrior && pSub->pOrderBy==0 );
+      pSub->pOrderBy = p->pOrderBy;
+      p->pOrderBy = 0;
+    }
+
+    /* Recursively resolve names in all subqueries in the FROM clause
+    */
+    if( pOuterNC ) pOuterNC->nNestedSelect++;
+    for(i=0; i<p->pSrc->nSrc; i++){
+      SrcItem *pItem = &p->pSrc->a[i];
+      assert( pItem->zName!=0
+              || pItem->fg.isSubquery );  /* Test of tag-20240424-1*/
+      if( pItem->fg.isSubquery
+       && (pItem->u4.pSubq->pSelect->selFlags & SF_Resolved)==0
+      ){
+        int nRef = pOuterNC ? pOuterNC->nRef : 0;
+        const char *zSavedContext = pParse->zAuthContext;
+
+        if( pItem->zName ) pParse->zAuthContext = pItem->zName;
+        sqlite3ResolveSelectNames(pParse, pItem->u4.pSubq->pSelect, pOuterNC);
+        pParse->zAuthContext = zSavedContext;
+        if( pParse->nErr ) return WRC_Abort;
+        assert( db->mallocFailed==0 );
+
+        /* If the number of references to the outer context changed when
+        ** expressions in the sub-select were resolved, the sub-select
+        ** is correlated. It is not required to check the refcount on any
+        ** but the innermost outer context object, as lookupName() increments
+        ** the refcount on all contexts between the current one and the
+        ** context containing the column when it resolves a name. */
+        if( pOuterNC ){
+          assert( pItem->fg.isCorrelated==0 && pOuterNC->nRef>=nRef );
+          pItem->fg.isCorrelated = (pOuterNC->nRef>nRef);
+        }
+      }
+    }
+    if( pOuterNC && ALWAYS(pOuterNC->nNestedSelect>0) ){
+      pOuterNC->nNestedSelect--;
+    }
+
+    /* Set up the local name-context to pass to sqlite3ResolveExprNames() to
+    ** resolve the result-set expression list.
+    */
+    sNC.ncFlags = NC_AllowAgg|NC_AllowWin;
+    sNC.pSrcList = p->pSrc;
+    sNC.pNext = pOuterNC;
+
+    /* Resolve names in the result set. */
+    if( sqlite3ResolveExprListNames(&sNC, p->pEList) ) return WRC_Abort;
+    sNC.ncFlags &= ~NC_AllowWin;
+
+    /* If there are no aggregate functions in the result-set, and no GROUP BY
+    ** expression, do not allow aggregates in any of the other expressions.
+    */
+    assert( (p->selFlags & SF_Aggregate)==0 );
+    pGroupBy = p->pGroupBy;
+    if( pGroupBy || (sNC.ncFlags & NC_HasAgg)!=0 ){
+      assert( NC_MinMaxAgg==SF_MinMaxAgg );
+      assert( NC_OrderAgg==SF_OrderByReqd );
+      p->selFlags |= SF_Aggregate | (sNC.ncFlags&(NC_MinMaxAgg|NC_OrderAgg));
+    }else{
+      sNC.ncFlags &= ~NC_AllowAgg;
+    }
+
+    /* Add the output column list to the name-context before parsing the
+    ** other expressions in the SELECT statement. This is so that
+    ** expressions in the WHERE clause (etc.) can refer to expressions by
+    ** aliases in the result set.
+    **
+    ** Minor point: If this is the case, then the expression will be
+    ** re-evaluated for each reference to it.
+    */
+    assert( (sNC.ncFlags & (NC_UAggInfo|NC_UUpsert|NC_UBaseReg))==0 );
+    sNC.uNC.pEList = p->pEList;
+    sNC.ncFlags |= NC_UEList;
+    if( p->pHaving ){
+      if( (p->selFlags & SF_Aggregate)==0 ){
+        sqlite3ErrorMsg(pParse, "HAVING clause on a non-aggregate query");
+        return WRC_Abort;
+      }
+      if( sqlite3ResolveExprNames(&sNC, p->pHaving) ) return WRC_Abort;
+    }
+    sNC.ncFlags |= NC_Where;
+    if( sqlite3ResolveExprNames(&sNC, p->pWhere) ) return WRC_Abort;
+    sNC.ncFlags &= ~NC_Where;
+
+    /* Resolve names in table-valued-function arguments */
+    for(i=0; i<p->pSrc->nSrc; i++){
+      SrcItem *pItem = &p->pSrc->a[i];
+      if( pItem->fg.isTabFunc
+       && sqlite3ResolveExprListNames(&sNC, pItem->u1.pFuncArg)
+      ){
+        return WRC_Abort;
+      }
+    }
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( IN_RENAME_OBJECT ){
+      Window *pWin;
+      for(pWin=p->pWinDefn; pWin; pWin=pWin->pNextWin){
+        if( sqlite3ResolveExprListNames(&sNC, pWin->pOrderBy)
+         || sqlite3ResolveExprListNames(&sNC, pWin->pPartition)
+        ){
+          return WRC_Abort;
+        }
+      }
+    }
+#endif
+
+    /* The ORDER BY and GROUP BY clauses may not refer to terms in
+    ** outer queries
+    */
+    sNC.pNext = 0;
+    sNC.ncFlags |= NC_AllowAgg|NC_AllowWin;
+
+    /* If this is a converted compound query, move the ORDER BY clause from
+    ** the sub-query back to the parent query. At this point each term
+    ** within the ORDER BY clause has been transformed to an integer value.
+    ** These integers will be replaced by copies of the corresponding result
+    ** set expressions by the call to resolveOrderGroupBy() below.  */
+    if( p->selFlags & SF_Converted ){
+      Select *pSub;
+      assert( p->pSrc->a[0].fg.isSubquery );
+      pSub = p->pSrc->a[0].u4.pSubq->pSelect;
+      assert( pSub!=0 );
+      p->pOrderBy = pSub->pOrderBy;
+      pSub->pOrderBy = 0;
+    }
+
+    /* Process the ORDER BY clause for singleton SELECT statements.
+    ** The ORDER BY clause for compounds SELECT statements is handled
+    ** below, after all of the result-sets for all of the elements of
+    ** the compound have been resolved.
+    **
+    ** If there is an ORDER BY clause on a term of a compound-select other
+    ** than the right-most term, then that is a syntax error.  But the error
+    ** is not detected until much later, and so we need to go ahead and
+    ** resolve those symbols on the incorrect ORDER BY for consistency.
+    */
+    if( p->pOrderBy!=0
+     && isCompound<=nCompound  /* Defer right-most ORDER BY of a compound */
+     && resolveOrderGroupBy(&sNC, p, p->pOrderBy, "ORDER")
+    ){
+      return WRC_Abort;
+    }
+    if( db->mallocFailed ){
+      return WRC_Abort;
+    }
+    sNC.ncFlags &= ~NC_AllowWin;
+
+    /* Resolve the GROUP BY clause.  At the same time, make sure
+    ** the GROUP BY clause does not contain aggregate functions.
+    */
+    if( pGroupBy ){
+      struct ExprList_item *pItem;
+
+      if( resolveOrderGroupBy(&sNC, p, pGroupBy, "GROUP") || db->mallocFailed ){
+        return WRC_Abort;
+      }
+      for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
+        if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
+          sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
+              "the GROUP BY clause");
+          return WRC_Abort;
+        }
+      }
+    }
+
+    /* If this is part of a compound SELECT, check that it has the right
+    ** number of expressions in the select list. */
+    if( p->pNext && p->pEList->nExpr!=p->pNext->pEList->nExpr ){
+      sqlite3SelectWrongNumTermsError(pParse, p->pNext);
+      return WRC_Abort;
+    }
+
+    /* Advance to the next term of the compound
+    */
+    p = p->pPrior;
+    nCompound++;
+  }
+
+  /* Resolve the ORDER BY on a compound SELECT after all terms of
+  ** the compound have been resolved.
+  */
+  if( isCompound && resolveCompoundOrderBy(pParse, pLeftmost) ){
+    return WRC_Abort;
+  }
+
+  return WRC_Prune;
+}
+
+/*
+** This routine walks an expression tree and resolves references to
+** table columns and result-set columns.  At the same time, do error
+** checking on function usage and set a flag if any aggregate functions
+** are seen.
+**
+** To resolve table columns references we look for nodes (or subtrees) of the
+** form X.Y.Z or Y.Z or just Z where
+**
+**      X:   The name of a database.  Ex:  "main" or "temp" or
+**           the symbolic name assigned to an ATTACH-ed database.
+**
+**      Y:   The name of a table in a FROM clause.  Or in a trigger
+**           one of the special names "old" or "new".
+**
+**      Z:   The name of a column in table Y.
+**
+** The node at the root of the subtree is modified as follows:
+**
+**    Expr.op        Changed to TK_COLUMN
+**    Expr.pTab      Points to the Table object for X.Y
+**    Expr.iColumn   The column index in X.Y.  -1 for the rowid.
+**    Expr.iTable    The VDBE cursor number for X.Y
+**
+**
+** To resolve result-set references, look for expression nodes of the
+** form Z (with no X and Y prefix) where the Z matches the right-hand
+** size of an AS clause in the result-set of a SELECT.  The Z expression
+** is replaced by a copy of the left-hand side of the result-set expression.
+** Table-name and function resolution occurs on the substituted expression
+** tree.  For example, in:
+**
+**      SELECT a+b AS x, c+d AS y FROM t1 ORDER BY x;
+**
+** The "x" term of the order by is replaced by "a+b" to render:
+**
+**      SELECT a+b AS x, c+d AS y FROM t1 ORDER BY a+b;
+**
+** Function calls are checked to make sure that the function is
+** defined and that the correct number of arguments are specified.
+** If the function is an aggregate function, then the NC_HasAgg flag is
+** set and the opcode is changed from TK_FUNCTION to TK_AGG_FUNCTION.
+** If an expression contains aggregate functions then the EP_Agg
+** property on the expression is set.
+**
+** An error message is left in pParse if anything is amiss.  The number
+** if errors is returned.
+*/
+SQLITE_PRIVATE int sqlite3ResolveExprNames(
+  NameContext *pNC,       /* Namespace to resolve expressions in. */
+  Expr *pExpr             /* The expression to be analyzed. */
+){
+  int savedHasAgg;
+  Walker w;
+
+  if( pExpr==0 ) return SQLITE_OK;
+  savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+  pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+  w.pParse = pNC->pParse;
+  w.xExprCallback = resolveExprStep;
+  w.xSelectCallback = (pNC->ncFlags & NC_NoSelect) ? 0 : resolveSelectStep;
+  w.xSelectCallback2 = 0;
+  w.u.pNC = pNC;
+#if SQLITE_MAX_EXPR_DEPTH>0
+  w.pParse->nHeight += pExpr->nHeight;
+  if( sqlite3ExprCheckHeight(w.pParse, w.pParse->nHeight) ){
+    return SQLITE_ERROR;
+  }
+#endif
+  assert( pExpr!=0 );
+  sqlite3WalkExprNN(&w, pExpr);
+#if SQLITE_MAX_EXPR_DEPTH>0
+  w.pParse->nHeight -= pExpr->nHeight;
+#endif
+  assert( EP_Agg==NC_HasAgg );
+  assert( EP_Win==NC_HasWin );
+  testcase( pNC->ncFlags & NC_HasAgg );
+  testcase( pNC->ncFlags & NC_HasWin );
+  ExprSetProperty(pExpr, pNC->ncFlags & (NC_HasAgg|NC_HasWin) );
+  pNC->ncFlags |= savedHasAgg;
+  return pNC->nNcErr>0 || w.pParse->nErr>0;
+}
+
+/*
+** Resolve all names for all expression in an expression list.  This is
+** just like sqlite3ResolveExprNames() except that it works for an expression
+** list rather than a single expression.
+**
+** The return value is SQLITE_OK (0) for success or SQLITE_ERROR (1) for a
+** failure.
+*/
+SQLITE_PRIVATE int sqlite3ResolveExprListNames(
+  NameContext *pNC,       /* Namespace to resolve expressions in. */
+  ExprList *pList         /* The expression list to be analyzed. */
+){
+  int i;
+  int savedHasAgg = 0;
+  Walker w;
+  if( pList==0 ) return SQLITE_OK;
+  w.pParse = pNC->pParse;
+  w.xExprCallback = resolveExprStep;
+  w.xSelectCallback = resolveSelectStep;
+  w.xSelectCallback2 = 0;
+  w.u.pNC = pNC;
+  savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+  pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+  for(i=0; i<pList->nExpr; i++){
+    Expr *pExpr = pList->a[i].pExpr;
+    if( pExpr==0 ) continue;
+#if SQLITE_MAX_EXPR_DEPTH>0
+    w.pParse->nHeight += pExpr->nHeight;
+    if( sqlite3ExprCheckHeight(w.pParse, w.pParse->nHeight) ){
+      return SQLITE_ERROR;
+    }
+#endif
+    sqlite3WalkExprNN(&w, pExpr);
+#if SQLITE_MAX_EXPR_DEPTH>0
+    w.pParse->nHeight -= pExpr->nHeight;
+#endif
+    assert( EP_Agg==NC_HasAgg );
+    assert( EP_Win==NC_HasWin );
+    testcase( pNC->ncFlags & NC_HasAgg );
+    testcase( pNC->ncFlags & NC_HasWin );
+    if( pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg) ){
+      ExprSetProperty(pExpr, pNC->ncFlags & (NC_HasAgg|NC_HasWin) );
+      savedHasAgg |= pNC->ncFlags &
+                          (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+      pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+    }
+    if( w.pParse->nErr>0 ) return SQLITE_ERROR;
+  }
+  pNC->ncFlags |= savedHasAgg;
+  return SQLITE_OK;
+}
+
+/*
+** Resolve all names in all expressions of a SELECT and in all
+** descendants of the SELECT, including compounds off of p->pPrior,
+** subqueries in expressions, and subqueries used as FROM clause
+** terms.
+**
+** See sqlite3ResolveExprNames() for a description of the kinds of
+** transformations that occur.
+**
+** All SELECT statements should have been expanded using
+** sqlite3SelectExpand() prior to invoking this routine.
+*/
+SQLITE_PRIVATE void sqlite3ResolveSelectNames(
+  Parse *pParse,         /* The parser context */
+  Select *p,             /* The SELECT statement being coded. */
+  NameContext *pOuterNC  /* Name context for parent SELECT statement */
+){
+  Walker w;
+
+  assert( p!=0 );
+  w.xExprCallback = resolveExprStep;
+  w.xSelectCallback = resolveSelectStep;
+  w.xSelectCallback2 = 0;
+  w.pParse = pParse;
+  w.u.pNC = pOuterNC;
+  sqlite3WalkSelect(&w, p);
+}
+
+/*
+** Resolve names in expressions that can only reference a single table
+** or which cannot reference any tables at all.  Examples:
+**
+**                                                    "type" flag
+**                                                    ------------
+**    (1)   CHECK constraints                         NC_IsCheck
+**    (2)   WHERE clauses on partial indices          NC_PartIdx
+**    (3)   Expressions in indexes on expressions     NC_IdxExpr
+**    (4)   Expression arguments to VACUUM INTO.      0
+**    (5)   GENERATED ALWAYS as expressions           NC_GenCol
+**
+** In all cases except (4), the Expr.iTable value for Expr.op==TK_COLUMN
+** nodes of the expression is set to -1 and the Expr.iColumn value is
+** set to the column number.  In case (4), TK_COLUMN nodes cause an error.
+**
+** Any errors cause an error message to be set in pParse.
+*/
+SQLITE_PRIVATE int sqlite3ResolveSelfReference(
+  Parse *pParse,   /* Parsing context */
+  Table *pTab,     /* The table being referenced, or NULL */
+  int type,        /* NC_IsCheck, NC_PartIdx, NC_IdxExpr, NC_GenCol, or 0 */
+  Expr *pExpr,     /* Expression to resolve.  May be NULL. */
+  ExprList *pList  /* Expression list to resolve.  May be NULL. */
+){
+  SrcList sSrc;                   /* Fake SrcList for pParse->pNewTable */
+  NameContext sNC;                /* Name context for pParse->pNewTable */
+  int rc;
+
+  assert( type==0 || pTab!=0 );
+  assert( type==NC_IsCheck || type==NC_PartIdx || type==NC_IdxExpr
+          || type==NC_GenCol || pTab==0 );
+  memset(&sNC, 0, sizeof(sNC));
+  memset(&sSrc, 0, sizeof(sSrc));
+  if( pTab ){
+    sSrc.nSrc = 1;
+    sSrc.a[0].zName = pTab->zName;
+    sSrc.a[0].pSTab = pTab;
+    sSrc.a[0].iCursor = -1;
+    if( pTab->pSchema!=pParse->db->aDb[1].pSchema ){
+      /* Cause EP_FromDDL to be set on TK_FUNCTION nodes of non-TEMP
+      ** schema elements */
+      type |= NC_FromDDL;
+    }
+  }
+  sNC.pParse = pParse;
+  sNC.pSrcList = &sSrc;
+  sNC.ncFlags = type | NC_IsDDL;
+  if( (rc = sqlite3ResolveExprNames(&sNC, pExpr))!=SQLITE_OK ) return rc;
+  if( pList ) rc = sqlite3ResolveExprListNames(&sNC, pList);
+  return rc;
+}
+
+/************** End of resolve.c *********************************************/
+/************** Begin file expr.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used for analyzing expressions and
+** for generating VDBE code that evaluates expressions in SQLite.
+*/
+/* #include "sqliteInt.h" */
+
+/* Forward declarations */
+static void exprCodeBetween(Parse*,Expr*,int,void(*)(Parse*,Expr*,int,int),int);
+static int exprCodeVector(Parse *pParse, Expr *p, int *piToFree);
+
+/*
+** Return the affinity character for a single column of a table.
+*/
+SQLITE_PRIVATE char sqlite3TableColumnAffinity(const Table *pTab, int iCol){
+  if( iCol<0 || NEVER(iCol>=pTab->nCol) ) return SQLITE_AFF_INTEGER;
+  return pTab->aCol[iCol].affinity;
+}
+
+/*
+** Return the 'affinity' of the expression pExpr if any.
+**
+** If pExpr is a column, a reference to a column via an 'AS' alias,
+** or a sub-select with a column as the return value, then the
+** affinity of that column is returned. Otherwise, 0x00 is returned,
+** indicating no affinity for the expression.
+**
+** i.e. the WHERE clause expressions in the following statements all
+** have an affinity:
+**
+** CREATE TABLE t1(a);
+** SELECT * FROM t1 WHERE a;
+** SELECT a AS b FROM t1 WHERE b;
+** SELECT * FROM t1 WHERE (select a from t1);
+*/
+SQLITE_PRIVATE char sqlite3ExprAffinity(const Expr *pExpr){
+  int op;
+  op = pExpr->op;
+  while( 1 /* exit-by-break */ ){
+    if( op==TK_COLUMN || (op==TK_AGG_COLUMN && pExpr->y.pTab!=0) ){
+      assert( ExprUseYTab(pExpr) );
+      assert( pExpr->y.pTab!=0 );
+      return sqlite3TableColumnAffinity(pExpr->y.pTab, pExpr->iColumn);
+    }
+    if( op==TK_SELECT ){
+      assert( ExprUseXSelect(pExpr) );
+      assert( pExpr->x.pSelect!=0 );
+      assert( pExpr->x.pSelect->pEList!=0 );
+      assert( pExpr->x.pSelect->pEList->a[0].pExpr!=0 );
+      return sqlite3ExprAffinity(pExpr->x.pSelect->pEList->a[0].pExpr);
+    }
+#ifndef SQLITE_OMIT_CAST
+    if( op==TK_CAST ){
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      return sqlite3AffinityType(pExpr->u.zToken, 0);
+    }
+#endif
+    if( op==TK_SELECT_COLUMN ){
+      assert( pExpr->pLeft!=0 && ExprUseXSelect(pExpr->pLeft) );
+      assert( pExpr->iColumn < pExpr->iTable );
+      assert( pExpr->iColumn >= 0 );
+      assert( pExpr->iTable==pExpr->pLeft->x.pSelect->pEList->nExpr );
+      return sqlite3ExprAffinity(
+          pExpr->pLeft->x.pSelect->pEList->a[pExpr->iColumn].pExpr
+      );
+    }
+    if( op==TK_VECTOR ){
+      assert( ExprUseXList(pExpr) );
+      return sqlite3ExprAffinity(pExpr->x.pList->a[0].pExpr);
+    }
+    if( ExprHasProperty(pExpr, EP_Skip|EP_IfNullRow) ){
+      assert( pExpr->op==TK_COLLATE
+           || pExpr->op==TK_IF_NULL_ROW
+           || (pExpr->op==TK_REGISTER && pExpr->op2==TK_IF_NULL_ROW) );
+      pExpr = pExpr->pLeft;
+      op = pExpr->op;
+      continue;
+    }
+    if( op!=TK_REGISTER ) break;
+    op = pExpr->op2;
+    if( NEVER( op==TK_REGISTER ) ) break;
+  }
+  return pExpr->affExpr;
+}
+
+/*
+** Make a guess at all the possible datatypes of the result that could
+** be returned by an expression.  Return a bitmask indicating the answer:
+**
+**     0x01         Numeric
+**     0x02         Text
+**     0x04         Blob
+**
+** If the expression must return NULL, then 0x00 is returned.
+*/
+SQLITE_PRIVATE int sqlite3ExprDataType(const Expr *pExpr){
+  while( pExpr ){
+    switch( pExpr->op ){
+      case TK_COLLATE:
+      case TK_IF_NULL_ROW:
+      case TK_UPLUS:  {
+        pExpr = pExpr->pLeft;
+        break;
+      }
+      case TK_NULL: {
+        pExpr = 0;
+        break;
+      }
+      case TK_STRING: {
+        return 0x02;
+      }
+      case TK_BLOB: {
+        return 0x04;
+      }
+      case TK_CONCAT: {
+        return 0x06;
+      }
+      case TK_VARIABLE:
+      case TK_AGG_FUNCTION:
+      case TK_FUNCTION: {
+        return 0x07;
+      }
+      case TK_COLUMN:
+      case TK_AGG_COLUMN:
+      case TK_SELECT:
+      case TK_CAST:
+      case TK_SELECT_COLUMN:
+      case TK_VECTOR:  {
+        int aff = sqlite3ExprAffinity(pExpr);
+        if( aff>=SQLITE_AFF_NUMERIC ) return 0x05;
+        if( aff==SQLITE_AFF_TEXT )    return 0x06;
+        return 0x07;
+      }
+      case TK_CASE: {
+        int res = 0;
+        int ii;
+        ExprList *pList = pExpr->x.pList;
+        assert( ExprUseXList(pExpr) && pList!=0 );
+        assert( pList->nExpr > 0);
+        for(ii=1; ii<pList->nExpr; ii+=2){
+          res |= sqlite3ExprDataType(pList->a[ii].pExpr);
+        }
+        if( pList->nExpr % 2 ){
+          res |= sqlite3ExprDataType(pList->a[pList->nExpr-1].pExpr);
+        }
+        return res;
+      }
+      default: {
+        return 0x01;
+      }
+    } /* End of switch(op) */
+  } /* End of while(pExpr) */
+  return 0x00;
+}
+
+/*
+** Set the collating sequence for expression pExpr to be the collating
+** sequence named by pToken.   Return a pointer to a new Expr node that
+** implements the COLLATE operator.
+**
+** If a memory allocation error occurs, that fact is recorded in pParse->db
+** and the pExpr parameter is returned unchanged.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprAddCollateToken(
+  const Parse *pParse,     /* Parsing context */
+  Expr *pExpr,             /* Add the "COLLATE" clause to this expression */
+  const Token *pCollName,  /* Name of collating sequence */
+  int dequote              /* True to dequote pCollName */
+){
+  if( pCollName->n>0 ){
+    Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLLATE, pCollName, dequote);
+    if( pNew ){
+      pNew->pLeft = pExpr;
+      pNew->flags |= EP_Collate|EP_Skip;
+      pExpr = pNew;
+    }
+  }
+  return pExpr;
+}
+SQLITE_PRIVATE Expr *sqlite3ExprAddCollateString(
+  const Parse *pParse,  /* Parsing context */
+  Expr *pExpr,          /* Add the "COLLATE" clause to this expression */
+  const char *zC        /* The collating sequence name */
+){
+  Token s;
+  assert( zC!=0 );
+  sqlite3TokenInit(&s, (char*)zC);
+  return sqlite3ExprAddCollateToken(pParse, pExpr, &s, 0);
+}
+
+/*
+** Skip over any TK_COLLATE operators.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprSkipCollate(Expr *pExpr){
+  while( pExpr && ExprHasProperty(pExpr, EP_Skip) ){
+    assert( pExpr->op==TK_COLLATE );
+    pExpr = pExpr->pLeft;
+  }
+  return pExpr;
+}
+
+/*
+** Skip over any TK_COLLATE operators and/or any unlikely()
+** or likelihood() or likely() functions at the root of an
+** expression.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprSkipCollateAndLikely(Expr *pExpr){
+  while( pExpr && ExprHasProperty(pExpr, EP_Skip|EP_Unlikely) ){
+    if( ExprHasProperty(pExpr, EP_Unlikely) ){
+      assert( ExprUseXList(pExpr) );
+      assert( pExpr->x.pList->nExpr>0 );
+      assert( pExpr->op==TK_FUNCTION );
+      pExpr = pExpr->x.pList->a[0].pExpr;
+    }else if( pExpr->op==TK_COLLATE ){
+      pExpr = pExpr->pLeft;
+    }else{
+      break;
+    }
+  }
+  return pExpr;
+}
+
+/*
+** Return the collation sequence for the expression pExpr. If
+** there is no defined collating sequence, return NULL.
+**
+** See also: sqlite3ExprNNCollSeq()
+**
+** The sqlite3ExprNNCollSeq() works the same exact that it returns the
+** default collation if pExpr has no defined collation.
+**
+** The collating sequence might be determined by a COLLATE operator
+** or by the presence of a column with a defined collating sequence.
+** COLLATE operators take first precedence.  Left operands take
+** precedence over right operands.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, const Expr *pExpr){
+  sqlite3 *db = pParse->db;
+  CollSeq *pColl = 0;
+  const Expr *p = pExpr;
+  while( p ){
+    int op = p->op;
+    if( op==TK_REGISTER ) op = p->op2;
+    if( (op==TK_AGG_COLUMN && p->y.pTab!=0)
+     || op==TK_COLUMN || op==TK_TRIGGER
+    ){
+      int j;
+      assert( ExprUseYTab(p) );
+      assert( p->y.pTab!=0 );
+      if( (j = p->iColumn)>=0 ){
+        const char *zColl = sqlite3ColumnColl(&p->y.pTab->aCol[j]);
+        pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);
+      }
+      break;
+    }
+    if( op==TK_CAST || op==TK_UPLUS ){
+      p = p->pLeft;
+      continue;
+    }
+    if( op==TK_VECTOR ){
+      assert( ExprUseXList(p) );
+      p = p->x.pList->a[0].pExpr;
+      continue;
+    }
+    if( op==TK_COLLATE ){
+      assert( !ExprHasProperty(p, EP_IntValue) );
+      pColl = sqlite3GetCollSeq(pParse, ENC(db), 0, p->u.zToken);
+      break;
+    }
+    if( p->flags & EP_Collate ){
+      if( p->pLeft && (p->pLeft->flags & EP_Collate)!=0 ){
+        p = p->pLeft;
+      }else{
+        Expr *pNext  = p->pRight;
+        /* The Expr.x union is never used at the same time as Expr.pRight */
+        assert( !ExprUseXList(p) || p->x.pList==0 || p->pRight==0 );
+        if( ExprUseXList(p) && p->x.pList!=0 && !db->mallocFailed ){
+          int i;
+          for(i=0; i<p->x.pList->nExpr; i++){
+            if( ExprHasProperty(p->x.pList->a[i].pExpr, EP_Collate) ){
+              pNext = p->x.pList->a[i].pExpr;
+              break;
+            }
+          }
+        }
+        p = pNext;
+      }
+    }else{
+      break;
+    }
+  }
+  if( sqlite3CheckCollSeq(pParse, pColl) ){
+    pColl = 0;
+  }
+  return pColl;
+}
+
+/*
+** Return the collation sequence for the expression pExpr. If
+** there is no defined collating sequence, return a pointer to the
+** default collation sequence.
+**
+** See also: sqlite3ExprCollSeq()
+**
+** The sqlite3ExprCollSeq() routine works the same except that it
+** returns NULL if there is no defined collation.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3ExprNNCollSeq(Parse *pParse, const Expr *pExpr){
+  CollSeq *p = sqlite3ExprCollSeq(pParse, pExpr);
+  if( p==0 ) p = pParse->db->pDfltColl;
+  assert( p!=0 );
+  return p;
+}
+
+/*
+** Return TRUE if the two expressions have equivalent collating sequences.
+*/
+SQLITE_PRIVATE int sqlite3ExprCollSeqMatch(Parse *pParse, const Expr *pE1, const Expr *pE2){
+  CollSeq *pColl1 = sqlite3ExprNNCollSeq(pParse, pE1);
+  CollSeq *pColl2 = sqlite3ExprNNCollSeq(pParse, pE2);
+  return sqlite3StrICmp(pColl1->zName, pColl2->zName)==0;
+}
+
+/*
+** pExpr is an operand of a comparison operator.  aff2 is the
+** type affinity of the other operand.  This routine returns the
+** type affinity that should be used for the comparison operator.
+*/
+SQLITE_PRIVATE char sqlite3CompareAffinity(const Expr *pExpr, char aff2){
+  char aff1 = sqlite3ExprAffinity(pExpr);
+  if( aff1>SQLITE_AFF_NONE && aff2>SQLITE_AFF_NONE ){
+    /* Both sides of the comparison are columns. If one has numeric
+    ** affinity, use that. Otherwise use no affinity.
+    */
+    if( sqlite3IsNumericAffinity(aff1) || sqlite3IsNumericAffinity(aff2) ){
+      return SQLITE_AFF_NUMERIC;
+    }else{
+      return SQLITE_AFF_BLOB;
+    }
+  }else{
+    /* One side is a column, the other is not. Use the columns affinity. */
+    assert( aff1<=SQLITE_AFF_NONE || aff2<=SQLITE_AFF_NONE );
+    return (aff1<=SQLITE_AFF_NONE ? aff2 : aff1) | SQLITE_AFF_NONE;
+  }
+}
+
+/*
+** pExpr is a comparison operator.  Return the type affinity that should
+** be applied to both operands prior to doing the comparison.
+*/
+static char comparisonAffinity(const Expr *pExpr){
+  char aff;
+  assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
+          pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
+          pExpr->op==TK_NE || pExpr->op==TK_IS || pExpr->op==TK_ISNOT );
+  assert( pExpr->pLeft );
+  aff = sqlite3ExprAffinity(pExpr->pLeft);
+  if( pExpr->pRight ){
+    aff = sqlite3CompareAffinity(pExpr->pRight, aff);
+  }else if( ExprUseXSelect(pExpr) ){
+    aff = sqlite3CompareAffinity(pExpr->x.pSelect->pEList->a[0].pExpr, aff);
+  }else if( aff==0 ){
+    aff = SQLITE_AFF_BLOB;
+  }
+  return aff;
+}
+
+/*
+** pExpr is a comparison expression, eg. '=', '<', IN(...) etc.
+** idx_affinity is the affinity of an indexed column. Return true
+** if the index with affinity idx_affinity may be used to implement
+** the comparison in pExpr.
+*/
+SQLITE_PRIVATE int sqlite3IndexAffinityOk(const Expr *pExpr, char idx_affinity){
+  char aff = comparisonAffinity(pExpr);
+  if( aff<SQLITE_AFF_TEXT ){
+    return 1;
+  }
+  if( aff==SQLITE_AFF_TEXT ){
+    return idx_affinity==SQLITE_AFF_TEXT;
+  }
+  return sqlite3IsNumericAffinity(idx_affinity);
+}
+
+/*
+** Return the P5 value that should be used for a binary comparison
+** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.
+*/
+static u8 binaryCompareP5(
+  const Expr *pExpr1,   /* Left operand */
+  const Expr *pExpr2,   /* Right operand */
+  int jumpIfNull        /* Extra flags added to P5 */
+){
+  u8 aff = (char)sqlite3ExprAffinity(pExpr2);
+  aff = (u8)sqlite3CompareAffinity(pExpr1, aff) | (u8)jumpIfNull;
+  return aff;
+}
+
+/*
+** Return a pointer to the collation sequence that should be used by
+** a binary comparison operator comparing pLeft and pRight.
+**
+** If the left hand expression has a collating sequence type, then it is
+** used. Otherwise the collation sequence for the right hand expression
+** is used, or the default (BINARY) if neither expression has a collating
+** type.
+**
+** Argument pRight (but not pLeft) may be a null pointer. In this case,
+** it is not considered.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3BinaryCompareCollSeq(
+  Parse *pParse,
+  const Expr *pLeft,
+  const Expr *pRight
+){
+  CollSeq *pColl;
+  assert( pLeft );
+  if( pLeft->flags & EP_Collate ){
+    pColl = sqlite3ExprCollSeq(pParse, pLeft);
+  }else if( pRight && (pRight->flags & EP_Collate)!=0 ){
+    pColl = sqlite3ExprCollSeq(pParse, pRight);
+  }else{
+    pColl = sqlite3ExprCollSeq(pParse, pLeft);
+    if( !pColl ){
+      pColl = sqlite3ExprCollSeq(pParse, pRight);
+    }
+  }
+  return pColl;
+}
+
+/* Expression p is a comparison operator.  Return a collation sequence
+** appropriate for the comparison operator.
+**
+** This is normally just a wrapper around sqlite3BinaryCompareCollSeq().
+** However, if the OP_Commuted flag is set, then the order of the operands
+** is reversed in the sqlite3BinaryCompareCollSeq() call so that the
+** correct collating sequence is found.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3ExprCompareCollSeq(Parse *pParse, const Expr *p){
+  if( ExprHasProperty(p, EP_Commuted) ){
+    return sqlite3BinaryCompareCollSeq(pParse, p->pRight, p->pLeft);
+  }else{
+    return sqlite3BinaryCompareCollSeq(pParse, p->pLeft, p->pRight);
+  }
+}
+
+/*
+** Generate code for a comparison operator.
+*/
+static int codeCompare(
+  Parse *pParse,    /* The parsing (and code generating) context */
+  Expr *pLeft,      /* The left operand */
+  Expr *pRight,     /* The right operand */
+  int opcode,       /* The comparison opcode */
+  int in1, int in2, /* Register holding operands */
+  int dest,         /* Jump here if true.  */
+  int jumpIfNull,   /* If true, jump if either operand is NULL */
+  int isCommuted    /* The comparison has been commuted */
+){
+  int p5;
+  int addr;
+  CollSeq *p4;
+
+  if( pParse->nErr ) return 0;
+  if( isCommuted ){
+    p4 = sqlite3BinaryCompareCollSeq(pParse, pRight, pLeft);
+  }else{
+    p4 = sqlite3BinaryCompareCollSeq(pParse, pLeft, pRight);
+  }
+  p5 = binaryCompareP5(pLeft, pRight, jumpIfNull);
+  addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
+                           (void*)p4, P4_COLLSEQ);
+  sqlite3VdbeChangeP5(pParse->pVdbe, (u16)p5);
+  return addr;
+}
+
+/*
+** Return true if expression pExpr is a vector, or false otherwise.
+**
+** A vector is defined as any expression that results in two or more
+** columns of result.  Every TK_VECTOR node is an vector because the
+** parser will not generate a TK_VECTOR with fewer than two entries.
+** But a TK_SELECT might be either a vector or a scalar. It is only
+** considered a vector if it has two or more result columns.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsVector(const Expr *pExpr){
+  return sqlite3ExprVectorSize(pExpr)>1;
+}
+
+/*
+** If the expression passed as the only argument is of type TK_VECTOR
+** return the number of expressions in the vector. Or, if the expression
+** is a sub-select, return the number of columns in the sub-select. For
+** any other type of expression, return 1.
+*/
+SQLITE_PRIVATE int sqlite3ExprVectorSize(const Expr *pExpr){
+  u8 op = pExpr->op;
+  if( op==TK_REGISTER ) op = pExpr->op2;
+  if( op==TK_VECTOR ){
+    assert( ExprUseXList(pExpr) );
+    return pExpr->x.pList->nExpr;
+  }else if( op==TK_SELECT ){
+    assert( ExprUseXSelect(pExpr) );
+    return pExpr->x.pSelect->pEList->nExpr;
+  }else{
+    return 1;
+  }
+}
+
+/*
+** Return a pointer to a subexpression of pVector that is the i-th
+** column of the vector (numbered starting with 0).  The caller must
+** ensure that i is within range.
+**
+** If pVector is really a scalar (and "scalar" here includes subqueries
+** that return a single column!) then return pVector unmodified.
+**
+** pVector retains ownership of the returned subexpression.
+**
+** If the vector is a (SELECT ...) then the expression returned is
+** just the expression for the i-th term of the result set, and may
+** not be ready for evaluation because the table cursor has not yet
+** been positioned.
+*/
+SQLITE_PRIVATE Expr *sqlite3VectorFieldSubexpr(Expr *pVector, int i){
+  assert( i<sqlite3ExprVectorSize(pVector) || pVector->op==TK_ERROR );
+  if( sqlite3ExprIsVector(pVector) ){
+    assert( pVector->op2==0 || pVector->op==TK_REGISTER );
+    if( pVector->op==TK_SELECT || pVector->op2==TK_SELECT ){
+      assert( ExprUseXSelect(pVector) );
+      return pVector->x.pSelect->pEList->a[i].pExpr;
+    }else{
+      assert( ExprUseXList(pVector) );
+      return pVector->x.pList->a[i].pExpr;
+    }
+  }
+  return pVector;
+}
+
+/*
+** Compute and return a new Expr object which when passed to
+** sqlite3ExprCode() will generate all necessary code to compute
+** the iField-th column of the vector expression pVector.
+**
+** It is ok for pVector to be a scalar (as long as iField==0).
+** In that case, this routine works like sqlite3ExprDup().
+**
+** The caller owns the returned Expr object and is responsible for
+** ensuring that the returned value eventually gets freed.
+**
+** The caller retains ownership of pVector.  If pVector is a TK_SELECT,
+** then the returned object will reference pVector and so pVector must remain
+** valid for the life of the returned object.  If pVector is a TK_VECTOR
+** or a scalar expression, then it can be deleted as soon as this routine
+** returns.
+**
+** A trick to cause a TK_SELECT pVector to be deleted together with
+** the returned Expr object is to attach the pVector to the pRight field
+** of the returned TK_SELECT_COLUMN Expr object.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprForVectorField(
+  Parse *pParse,       /* Parsing context */
+  Expr *pVector,       /* The vector.  List of expressions or a sub-SELECT */
+  int iField,          /* Which column of the vector to return */
+  int nField           /* Total number of columns in the vector */
+){
+  Expr *pRet;
+  if( pVector->op==TK_SELECT ){
+    assert( ExprUseXSelect(pVector) );
+    /* The TK_SELECT_COLUMN Expr node:
+    **
+    ** pLeft:           pVector containing TK_SELECT.  Not deleted.
+    ** pRight:          not used.  But recursively deleted.
+    ** iColumn:         Index of a column in pVector
+    ** iTable:          0 or the number of columns on the LHS of an assignment
+    ** pLeft->iTable:   First in an array of register holding result, or 0
+    **                  if the result is not yet computed.
+    **
+    ** sqlite3ExprDelete() specifically skips the recursive delete of
+    ** pLeft on TK_SELECT_COLUMN nodes.  But pRight is followed, so pVector
+    ** can be attached to pRight to cause this node to take ownership of
+    ** pVector.  Typically there will be multiple TK_SELECT_COLUMN nodes
+    ** with the same pLeft pointer to the pVector, but only one of them
+    ** will own the pVector.
+    */
+    pRet = sqlite3PExpr(pParse, TK_SELECT_COLUMN, 0, 0);
+    if( pRet ){
+      ExprSetProperty(pRet, EP_FullSize);
+      pRet->iTable = nField;
+      pRet->iColumn = iField;
+      pRet->pLeft = pVector;
+    }
+  }else{
+    if( pVector->op==TK_VECTOR ){
+      Expr **ppVector;
+      assert( ExprUseXList(pVector) );
+      ppVector = &pVector->x.pList->a[iField].pExpr;
+      pVector = *ppVector;
+      if( IN_RENAME_OBJECT ){
+        /* This must be a vector UPDATE inside a trigger */
+        *ppVector = 0;
+        return pVector;
+      }
+    }
+    pRet = sqlite3ExprDup(pParse->db, pVector, 0);
+  }
+  return pRet;
+}
+
+/*
+** If expression pExpr is of type TK_SELECT, generate code to evaluate
+** it. Return the register in which the result is stored (or, if the
+** sub-select returns more than one column, the first in an array
+** of registers in which the result is stored).
+**
+** If pExpr is not a TK_SELECT expression, return 0.
+*/
+static int exprCodeSubselect(Parse *pParse, Expr *pExpr){
+  int reg = 0;
+#ifndef SQLITE_OMIT_SUBQUERY
+  if( pExpr->op==TK_SELECT ){
+    reg = sqlite3CodeSubselect(pParse, pExpr);
+  }
+#endif
+  return reg;
+}
+
+/*
+** Argument pVector points to a vector expression - either a TK_VECTOR
+** or TK_SELECT that returns more than one column. This function returns
+** the register number of a register that contains the value of
+** element iField of the vector.
+**
+** If pVector is a TK_SELECT expression, then code for it must have
+** already been generated using the exprCodeSubselect() routine. In this
+** case parameter regSelect should be the first in an array of registers
+** containing the results of the sub-select.
+**
+** If pVector is of type TK_VECTOR, then code for the requested field
+** is generated. In this case (*pRegFree) may be set to the number of
+** a temporary register to be freed by the caller before returning.
+**
+** Before returning, output parameter (*ppExpr) is set to point to the
+** Expr object corresponding to element iElem of the vector.
+*/
+static int exprVectorRegister(
+  Parse *pParse,                  /* Parse context */
+  Expr *pVector,                  /* Vector to extract element from */
+  int iField,                     /* Field to extract from pVector */
+  int regSelect,                  /* First in array of registers */
+  Expr **ppExpr,                  /* OUT: Expression element */
+  int *pRegFree                   /* OUT: Temp register to free */
+){
+  u8 op = pVector->op;
+  assert( op==TK_VECTOR || op==TK_REGISTER || op==TK_SELECT || op==TK_ERROR );
+  if( op==TK_REGISTER ){
+    *ppExpr = sqlite3VectorFieldSubexpr(pVector, iField);
+    return pVector->iTable+iField;
+  }
+  if( op==TK_SELECT ){
+    assert( ExprUseXSelect(pVector) );
+    *ppExpr = pVector->x.pSelect->pEList->a[iField].pExpr;
+     return regSelect+iField;
+  }
+  if( op==TK_VECTOR ){
+    assert( ExprUseXList(pVector) );
+    *ppExpr = pVector->x.pList->a[iField].pExpr;
+    return sqlite3ExprCodeTemp(pParse, *ppExpr, pRegFree);
+  }
+  return 0;
+}
+
+/*
+** Expression pExpr is a comparison between two vector values. Compute
+** the result of the comparison (1, 0, or NULL) and write that
+** result into register dest.
+**
+** The caller must satisfy the following preconditions:
+**
+**    if pExpr->op==TK_IS:      op==TK_EQ and p5==SQLITE_NULLEQ
+**    if pExpr->op==TK_ISNOT:   op==TK_NE and p5==SQLITE_NULLEQ
+**    otherwise:                op==pExpr->op and p5==0
+*/
+static void codeVectorCompare(
+  Parse *pParse,        /* Code generator context */
+  Expr *pExpr,          /* The comparison operation */
+  int dest,             /* Write results into this register */
+  u8 op,                /* Comparison operator */
+  u8 p5                 /* SQLITE_NULLEQ or zero */
+){
+  Vdbe *v = pParse->pVdbe;
+  Expr *pLeft = pExpr->pLeft;
+  Expr *pRight = pExpr->pRight;
+  int nLeft = sqlite3ExprVectorSize(pLeft);
+  int i;
+  int regLeft = 0;
+  int regRight = 0;
+  u8 opx = op;
+  int addrCmp = 0;
+  int addrDone = sqlite3VdbeMakeLabel(pParse);
+  int isCommuted = ExprHasProperty(pExpr,EP_Commuted);
+
+  assert( !ExprHasVVAProperty(pExpr,EP_Immutable) );
+  if( pParse->nErr ) return;
+  if( nLeft!=sqlite3ExprVectorSize(pRight) ){
+    sqlite3ErrorMsg(pParse, "row value misused");
+    return;
+  }
+  assert( pExpr->op==TK_EQ || pExpr->op==TK_NE
+       || pExpr->op==TK_IS || pExpr->op==TK_ISNOT
+       || pExpr->op==TK_LT || pExpr->op==TK_GT
+       || pExpr->op==TK_LE || pExpr->op==TK_GE
+  );
+  assert( pExpr->op==op || (pExpr->op==TK_IS && op==TK_EQ)
+            || (pExpr->op==TK_ISNOT && op==TK_NE) );
+  assert( p5==0 || pExpr->op!=op );
+  assert( p5==SQLITE_NULLEQ || pExpr->op==op );
+
+  if( op==TK_LE ) opx = TK_LT;
+  if( op==TK_GE ) opx = TK_GT;
+  if( op==TK_NE ) opx = TK_EQ;
+
+  regLeft = exprCodeSubselect(pParse, pLeft);
+  regRight = exprCodeSubselect(pParse, pRight);
+
+  sqlite3VdbeAddOp2(v, OP_Integer, 1, dest);
+  for(i=0; 1 /*Loop exits by "break"*/; i++){
+    int regFree1 = 0, regFree2 = 0;
+    Expr *pL = 0, *pR = 0;
+    int r1, r2;
+    assert( i>=0 && i<nLeft );
+    if( addrCmp ) sqlite3VdbeJumpHere(v, addrCmp);
+    r1 = exprVectorRegister(pParse, pLeft, i, regLeft, &pL, ®Free1);
+    r2 = exprVectorRegister(pParse, pRight, i, regRight, &pR, ®Free2);
+    addrCmp = sqlite3VdbeCurrentAddr(v);
+    codeCompare(pParse, pL, pR, opx, r1, r2, addrDone, p5, isCommuted);
+    testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+    testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+    testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+    testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+    testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
+    testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
+    sqlite3ReleaseTempReg(pParse, regFree1);
+    sqlite3ReleaseTempReg(pParse, regFree2);
+    if( (opx==TK_LT || opx==TK_GT) && i<nLeft-1 ){
+      addrCmp = sqlite3VdbeAddOp0(v, OP_ElseEq);
+      testcase(opx==TK_LT); VdbeCoverageIf(v,opx==TK_LT);
+      testcase(opx==TK_GT); VdbeCoverageIf(v,opx==TK_GT);
+    }
+    if( p5==SQLITE_NULLEQ ){
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, dest);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_ZeroOrNull, r1, dest, r2);
+    }
+    if( i==nLeft-1 ){
+      break;
+    }
+    if( opx==TK_EQ ){
+      sqlite3VdbeAddOp2(v, OP_NotNull, dest, addrDone); VdbeCoverage(v);
+    }else{
+      assert( op==TK_LT || op==TK_GT || op==TK_LE || op==TK_GE );
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrDone);
+      if( i==nLeft-2 ) opx = op;
+    }
+  }
+  sqlite3VdbeJumpHere(v, addrCmp);
+  sqlite3VdbeResolveLabel(v, addrDone);
+  if( op==TK_NE ){
+    sqlite3VdbeAddOp2(v, OP_Not, dest, dest);
+  }
+}
+
+#if SQLITE_MAX_EXPR_DEPTH>0
+/*
+** Check that argument nHeight is less than or equal to the maximum
+** expression depth allowed. If it is not, leave an error message in
+** pParse.
+*/
+SQLITE_PRIVATE int sqlite3ExprCheckHeight(Parse *pParse, int nHeight){
+  int rc = SQLITE_OK;
+  int mxHeight = pParse->db->aLimit[SQLITE_LIMIT_EXPR_DEPTH];
+  if( nHeight>mxHeight ){
+    sqlite3ErrorMsg(pParse,
+       "Expression tree is too large (maximum depth %d)", mxHeight
+    );
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/* The following three functions, heightOfExpr(), heightOfExprList()
+** and heightOfSelect(), are used to determine the maximum height
+** of any expression tree referenced by the structure passed as the
+** first argument.
+**
+** If this maximum height is greater than the current value pointed
+** to by pnHeight, the second parameter, then set *pnHeight to that
+** value.
+*/
+static void heightOfExpr(const Expr *p, int *pnHeight){
+  if( p ){
+    if( p->nHeight>*pnHeight ){
+      *pnHeight = p->nHeight;
+    }
+  }
+}
+static void heightOfExprList(const ExprList *p, int *pnHeight){
+  if( p ){
+    int i;
+    for(i=0; i<p->nExpr; i++){
+      heightOfExpr(p->a[i].pExpr, pnHeight);
+    }
+  }
+}
+static void heightOfSelect(const Select *pSelect, int *pnHeight){
+  const Select *p;
+  for(p=pSelect; p; p=p->pPrior){
+    heightOfExpr(p->pWhere, pnHeight);
+    heightOfExpr(p->pHaving, pnHeight);
+    heightOfExpr(p->pLimit, pnHeight);
+    heightOfExprList(p->pEList, pnHeight);
+    heightOfExprList(p->pGroupBy, pnHeight);
+    heightOfExprList(p->pOrderBy, pnHeight);
+  }
+}
+
+/*
+** Set the Expr.nHeight variable in the structure passed as an
+** argument. An expression with no children, Expr.pList or
+** Expr.pSelect member has a height of 1. Any other expression
+** has a height equal to the maximum height of any other
+** referenced Expr plus one.
+**
+** Also propagate EP_Propagate flags up from Expr.x.pList to Expr.flags,
+** if appropriate.
+*/
+static void exprSetHeight(Expr *p){
+  int nHeight = p->pLeft ? p->pLeft->nHeight : 0;
+  if( NEVER(p->pRight) && p->pRight->nHeight>nHeight ){
+    nHeight = p->pRight->nHeight;
+  }
+  if( ExprUseXSelect(p) ){
+    heightOfSelect(p->x.pSelect, &nHeight);
+  }else if( p->x.pList ){
+    heightOfExprList(p->x.pList, &nHeight);
+    p->flags |= EP_Propagate & sqlite3ExprListFlags(p->x.pList);
+  }
+  p->nHeight = nHeight + 1;
+}
+
+/*
+** Set the Expr.nHeight variable using the exprSetHeight() function. If
+** the height is greater than the maximum allowed expression depth,
+** leave an error in pParse.
+**
+** Also propagate all EP_Propagate flags from the Expr.x.pList into
+** Expr.flags.
+*/
+SQLITE_PRIVATE void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p){
+  if( pParse->nErr ) return;
+  exprSetHeight(p);
+  sqlite3ExprCheckHeight(pParse, p->nHeight);
+}
+
+/*
+** Return the maximum height of any expression tree referenced
+** by the select statement passed as an argument.
+*/
+SQLITE_PRIVATE int sqlite3SelectExprHeight(const Select *p){
+  int nHeight = 0;
+  heightOfSelect(p, &nHeight);
+  return nHeight;
+}
+#else /* ABOVE:  Height enforcement enabled.  BELOW: Height enforcement off */
+/*
+** Propagate all EP_Propagate flags from the Expr.x.pList into
+** Expr.flags.
+*/
+SQLITE_PRIVATE void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p){
+  if( pParse->nErr ) return;
+  if( p && ExprUseXList(p) && p->x.pList ){
+    p->flags |= EP_Propagate & sqlite3ExprListFlags(p->x.pList);
+  }
+}
+#define exprSetHeight(y)
+#endif /* SQLITE_MAX_EXPR_DEPTH>0 */
+
+/*
+** Set the error offset for an Expr node, if possible.
+*/
+SQLITE_PRIVATE void sqlite3ExprSetErrorOffset(Expr *pExpr, int iOfst){
+  if( pExpr==0 ) return;
+  if( NEVER(ExprUseWJoin(pExpr)) ) return;
+  pExpr->w.iOfst = iOfst;
+}
+
+/*
+** This routine is the core allocator for Expr nodes.
+**
+** Construct a new expression node and return a pointer to it.  Memory
+** for this node and for the pToken argument is a single allocation
+** obtained from sqlite3DbMalloc().  The calling function
+** is responsible for making sure the node eventually gets freed.
+**
+** If dequote is true, then the token (if it exists) is dequoted.
+** If dequote is false, no dequoting is performed.  The deQuote
+** parameter is ignored if pToken is NULL or if the token does not
+** appear to be quoted.  If the quotes were of the form "..." (double-quotes)
+** then the EP_DblQuoted flag is set on the expression node.
+**
+** Special case (tag-20240227-a):  If op==TK_INTEGER and pToken points to
+** a string that can be translated into a 32-bit integer, then the token is
+** not stored in u.zToken.  Instead, the integer values is written
+** into u.iValue and the EP_IntValue flag is set. No extra storage
+** is allocated to hold the integer text and the dequote flag is ignored.
+** See also tag-20240227-b.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprAlloc(
+  sqlite3 *db,            /* Handle for sqlite3DbMallocRawNN() */
+  int op,                 /* Expression opcode */
+  const Token *pToken,    /* Token argument.  Might be NULL */
+  int dequote             /* True to dequote */
+){
+  Expr *pNew;
+  int nExtra = 0;
+  int iValue = 0;
+
+  assert( db!=0 );
+  if( pToken ){
+    if( op!=TK_INTEGER || pToken->z==0
+          || sqlite3GetInt32(pToken->z, &iValue)==0 ){
+      nExtra = pToken->n+1;  /* tag-20240227-a */
+      assert( iValue>=0 );
+    }
+  }
+  pNew = sqlite3DbMallocRawNN(db, sizeof(Expr)+nExtra);
+  if( pNew ){
+    memset(pNew, 0, sizeof(Expr));
+    pNew->op = (u8)op;
+    pNew->iAgg = -1;
+    if( pToken ){
+      if( nExtra==0 ){
+        pNew->flags |= EP_IntValue|EP_Leaf|(iValue?EP_IsTrue:EP_IsFalse);
+        pNew->u.iValue = iValue;
+      }else{
+        pNew->u.zToken = (char*)&pNew[1];
+        assert( pToken->z!=0 || pToken->n==0 );
+        if( pToken->n ) memcpy(pNew->u.zToken, pToken->z, pToken->n);
+        pNew->u.zToken[pToken->n] = 0;
+        if( dequote && sqlite3Isquote(pNew->u.zToken[0]) ){
+          sqlite3DequoteExpr(pNew);
+        }
+      }
+    }
+#if SQLITE_MAX_EXPR_DEPTH>0
+    pNew->nHeight = 1;
+#endif
+  }
+  return pNew;
+}
+
+/*
+** Allocate a new expression node from a zero-terminated token that has
+** already been dequoted.
+*/
+SQLITE_PRIVATE Expr *sqlite3Expr(
+  sqlite3 *db,            /* Handle for sqlite3DbMallocZero() (may be null) */
+  int op,                 /* Expression opcode */
+  const char *zToken      /* Token argument.  Might be NULL */
+){
+  Token x;
+  x.z = zToken;
+  x.n = sqlite3Strlen30(zToken);
+  return sqlite3ExprAlloc(db, op, &x, 0);
+}
+
+/*
+** Attach subtrees pLeft and pRight to the Expr node pRoot.
+**
+** If pRoot==NULL that means that a memory allocation error has occurred.
+** In that case, delete the subtrees pLeft and pRight.
+*/
+SQLITE_PRIVATE void sqlite3ExprAttachSubtrees(
+  sqlite3 *db,
+  Expr *pRoot,
+  Expr *pLeft,
+  Expr *pRight
+){
+  if( pRoot==0 ){
+    assert( db->mallocFailed );
+    sqlite3ExprDelete(db, pLeft);
+    sqlite3ExprDelete(db, pRight);
+  }else{
+    assert( ExprUseXList(pRoot) );
+    assert( pRoot->x.pSelect==0 );
+    if( pRight ){
+      pRoot->pRight = pRight;
+      pRoot->flags |= EP_Propagate & pRight->flags;
+#if SQLITE_MAX_EXPR_DEPTH>0
+      pRoot->nHeight = pRight->nHeight+1;
+    }else{
+      pRoot->nHeight = 1;
+#endif
+    }
+    if( pLeft ){
+      pRoot->pLeft = pLeft;
+      pRoot->flags |= EP_Propagate & pLeft->flags;
+#if SQLITE_MAX_EXPR_DEPTH>0
+      if( pLeft->nHeight>=pRoot->nHeight ){
+        pRoot->nHeight = pLeft->nHeight+1;
+      }
+#endif
+    }
+  }
+}
+
+/*
+** Allocate an Expr node which joins as many as two subtrees.
+**
+** One or both of the subtrees can be NULL.  Return a pointer to the new
+** Expr node.  Or, if an OOM error occurs, set pParse->db->mallocFailed,
+** free the subtrees and return NULL.
+*/
+SQLITE_PRIVATE Expr *sqlite3PExpr(
+  Parse *pParse,          /* Parsing context */
+  int op,                 /* Expression opcode */
+  Expr *pLeft,            /* Left operand */
+  Expr *pRight            /* Right operand */
+){
+  Expr *p;
+  p = sqlite3DbMallocRawNN(pParse->db, sizeof(Expr));
+  if( p ){
+    memset(p, 0, sizeof(Expr));
+    p->op = op & 0xff;
+    p->iAgg = -1;
+    sqlite3ExprAttachSubtrees(pParse->db, p, pLeft, pRight);
+    sqlite3ExprCheckHeight(pParse, p->nHeight);
+  }else{
+    sqlite3ExprDelete(pParse->db, pLeft);
+    sqlite3ExprDelete(pParse->db, pRight);
+  }
+  return p;
+}
+
+/*
+** Add pSelect to the Expr.x.pSelect field.  Or, if pExpr is NULL (due
+** do a memory allocation failure) then delete the pSelect object.
+*/
+SQLITE_PRIVATE void sqlite3PExprAddSelect(Parse *pParse, Expr *pExpr, Select *pSelect){
+  if( pExpr ){
+    pExpr->x.pSelect = pSelect;
+    ExprSetProperty(pExpr, EP_xIsSelect|EP_Subquery);
+    sqlite3ExprSetHeightAndFlags(pParse, pExpr);
+  }else{
+    assert( pParse->db->mallocFailed );
+    sqlite3SelectDelete(pParse->db, pSelect);
+  }
+}
+
+/*
+** Expression list pEList is a list of vector values. This function
+** converts the contents of pEList to a VALUES(...) Select statement
+** returning 1 row for each element of the list. For example, the
+** expression list:
+**
+**   ( (1,2), (3,4) (5,6) )
+**
+** is translated to the equivalent of:
+**
+**   VALUES(1,2), (3,4), (5,6)
+**
+** Each of the vector values in pEList must contain exactly nElem terms.
+** If a list element that is not a vector or does not contain nElem terms,
+** an error message is left in pParse.
+**
+** This is used as part of processing IN(...) expressions with a list
+** of vectors on the RHS. e.g. "... IN ((1,2), (3,4), (5,6))".
+*/
+SQLITE_PRIVATE Select *sqlite3ExprListToValues(Parse *pParse, int nElem, ExprList *pEList){
+  int ii;
+  Select *pRet = 0;
+  assert( nElem>1 );
+  for(ii=0; ii<pEList->nExpr; ii++){
+    Select *pSel;
+    Expr *pExpr = pEList->a[ii].pExpr;
+    int nExprElem;
+    if( pExpr->op==TK_VECTOR ){
+      assert( ExprUseXList(pExpr) );
+      nExprElem = pExpr->x.pList->nExpr;
+    }else{
+      nExprElem = 1;
+    }
+    if( nExprElem!=nElem ){
+      sqlite3ErrorMsg(pParse, "IN(...) element has %d term%s - expected %d",
+          nExprElem, nExprElem>1?"s":"", nElem
+      );
+      break;
+    }
+    assert( ExprUseXList(pExpr) );
+    pSel = sqlite3SelectNew(pParse, pExpr->x.pList, 0, 0, 0, 0, 0, SF_Values,0);
+    pExpr->x.pList = 0;
+    if( pSel ){
+      if( pRet ){
+        pSel->op = TK_ALL;
+        pSel->pPrior = pRet;
+      }
+      pRet = pSel;
+    }
+  }
+
+  if( pRet && pRet->pPrior ){
+    pRet->selFlags |= SF_MultiValue;
+  }
+  sqlite3ExprListDelete(pParse->db, pEList);
+  return pRet;
+}
+
+/*
+** Join two expressions using an AND operator.  If either expression is
+** NULL, then just return the other expression.
+**
+** If one side or the other of the AND is known to be false, and neither side
+** is part of an ON clause, then instead of returning an AND expression,
+** just return a constant expression with a value of false.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprAnd(Parse *pParse, Expr *pLeft, Expr *pRight){
+  sqlite3 *db = pParse->db;
+  if( pLeft==0  ){
+    return pRight;
+  }else if( pRight==0 ){
+    return pLeft;
+  }else{
+    u32 f = pLeft->flags | pRight->flags;
+    if( (f&(EP_OuterON|EP_InnerON|EP_IsFalse))==EP_IsFalse
+     && !IN_RENAME_OBJECT
+    ){
+      sqlite3ExprDeferredDelete(pParse, pLeft);
+      sqlite3ExprDeferredDelete(pParse, pRight);
+      return sqlite3Expr(db, TK_INTEGER, "0");
+    }else{
+      return sqlite3PExpr(pParse, TK_AND, pLeft, pRight);
+    }
+  }
+}
+
+/*
+** Construct a new expression node for a function with multiple
+** arguments.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprFunction(
+  Parse *pParse,        /* Parsing context */
+  ExprList *pList,      /* Argument list */
+  const Token *pToken,  /* Name of the function */
+  int eDistinct         /* SF_Distinct or SF_ALL or 0 */
+){
+  Expr *pNew;
+  sqlite3 *db = pParse->db;
+  assert( pToken );
+  pNew = sqlite3ExprAlloc(db, TK_FUNCTION, pToken, 1);
+  if( pNew==0 ){
+    sqlite3ExprListDelete(db, pList); /* Avoid memory leak when malloc fails */
+    return 0;
+  }
+  assert( !ExprHasProperty(pNew, EP_InnerON|EP_OuterON) );
+  pNew->w.iOfst = (int)(pToken->z - pParse->zTail);
+  if( pList
+   && pList->nExpr > pParse->db->aLimit[SQLITE_LIMIT_FUNCTION_ARG]
+   && !pParse->nested
+  ){
+    sqlite3ErrorMsg(pParse, "too many arguments on function %T", pToken);
+  }
+  pNew->x.pList = pList;
+  ExprSetProperty(pNew, EP_HasFunc);
+  assert( ExprUseXList(pNew) );
+  sqlite3ExprSetHeightAndFlags(pParse, pNew);
+  if( eDistinct==SF_Distinct ) ExprSetProperty(pNew, EP_Distinct);
+  return pNew;
+}
+
+/*
+** Report an error when attempting to use an ORDER BY clause within
+** the arguments of a non-aggregate function.
+*/
+SQLITE_PRIVATE void sqlite3ExprOrderByAggregateError(Parse *pParse, Expr *p){
+  sqlite3ErrorMsg(pParse,
+     "ORDER BY may not be used with non-aggregate %#T()", p
+  );
+}
+
+/*
+** Attach an ORDER BY clause to a function call.
+**
+**     functionname( arguments ORDER BY sortlist )
+**     \_____________________/          \______/
+**             pExpr                    pOrderBy
+**
+** The ORDER BY clause is inserted into a new Expr node of type TK_ORDER
+** and added to the Expr.pLeft field of the parent TK_FUNCTION node.
+*/
+SQLITE_PRIVATE void sqlite3ExprAddFunctionOrderBy(
+  Parse *pParse,        /* Parsing context */
+  Expr *pExpr,          /* The function call to which ORDER BY is to be added */
+  ExprList *pOrderBy    /* The ORDER BY clause to add */
+){
+  Expr *pOB;
+  sqlite3 *db = pParse->db;
+  if( NEVER(pOrderBy==0) ){
+    assert( db->mallocFailed );
+    return;
+  }
+  if( pExpr==0 ){
+    assert( db->mallocFailed );
+    sqlite3ExprListDelete(db, pOrderBy);
+    return;
+  }
+  assert( pExpr->op==TK_FUNCTION );
+  assert( pExpr->pLeft==0 );
+  assert( ExprUseXList(pExpr) );
+  if( pExpr->x.pList==0 || NEVER(pExpr->x.pList->nExpr==0) ){
+    /* Ignore ORDER BY on zero-argument aggregates */
+    sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric, pOrderBy);
+    return;
+  }
+  if( IsWindowFunc(pExpr) ){
+    sqlite3ExprOrderByAggregateError(pParse, pExpr);
+    sqlite3ExprListDelete(db, pOrderBy);
+    return;
+  }
+
+  pOB = sqlite3ExprAlloc(db, TK_ORDER, 0, 0);
+  if( pOB==0 ){
+    sqlite3ExprListDelete(db, pOrderBy);
+    return;
+  }
+  pOB->x.pList = pOrderBy;
+  assert( ExprUseXList(pOB) );
+  pExpr->pLeft = pOB;
+  ExprSetProperty(pOB, EP_FullSize);
+}
+
+/*
+** Check to see if a function is usable according to current access
+** rules:
+**
+**    SQLITE_FUNC_DIRECT    -     Only usable from top-level SQL
+**
+**    SQLITE_FUNC_UNSAFE    -     Usable if TRUSTED_SCHEMA or from
+**                                top-level SQL
+**
+** If the function is not usable, create an error.
+*/
+SQLITE_PRIVATE void sqlite3ExprFunctionUsable(
+  Parse *pParse,         /* Parsing and code generating context */
+  const Expr *pExpr,     /* The function invocation */
+  const FuncDef *pDef    /* The function being invoked */
+){
+  assert( !IN_RENAME_OBJECT );
+  assert( (pDef->funcFlags & (SQLITE_FUNC_DIRECT|SQLITE_FUNC_UNSAFE))!=0 );
+  if( ExprHasProperty(pExpr, EP_FromDDL) ){
+    if( (pDef->funcFlags & SQLITE_FUNC_DIRECT)!=0
+     || (pParse->db->flags & SQLITE_TrustedSchema)==0
+    ){
+      /* Functions prohibited in triggers and views if:
+      **     (1) tagged with SQLITE_DIRECTONLY
+      **     (2) not tagged with SQLITE_INNOCUOUS (which means it
+      **         is tagged with SQLITE_FUNC_UNSAFE) and
+      **         SQLITE_DBCONFIG_TRUSTED_SCHEMA is off (meaning
+      **         that the schema is possibly tainted).
+      */
+      sqlite3ErrorMsg(pParse, "unsafe use of %#T()", pExpr);
+    }
+  }
+}
+
+/*
+** Assign a variable number to an expression that encodes a wildcard
+** in the original SQL statement.
+**
+** Wildcards consisting of a single "?" are assigned the next sequential
+** variable number.
+**
+** Wildcards of the form "?nnn" are assigned the number "nnn".  We make
+** sure "nnn" is not too big to avoid a denial of service attack when
+** the SQL statement comes from an external source.
+**
+** Wildcards of the form ":aaa", "@aaa", or "$aaa" are assigned the same number
+** as the previous instance of the same wildcard.  Or if this is the first
+** instance of the wildcard, the next sequential variable number is
+** assigned.
+*/
+SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr, u32 n){
+  sqlite3 *db = pParse->db;
+  const char *z;
+  ynVar x;
+
+  if( pExpr==0 ) return;
+  assert( !ExprHasProperty(pExpr, EP_IntValue|EP_Reduced|EP_TokenOnly) );
+  z = pExpr->u.zToken;
+  assert( z!=0 );
+  assert( z[0]!=0 );
+  assert( n==(u32)sqlite3Strlen30(z) );
+  if( z[1]==0 ){
+    /* Wildcard of the form "?".  Assign the next variable number */
+    assert( z[0]=='?' );
+    x = (ynVar)(++pParse->nVar);
+  }else{
+    int doAdd = 0;
+    if( z[0]=='?' ){
+      /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
+      ** use it as the variable number */
+      i64 i;
+      int bOk;
+      if( n==2 ){ /*OPTIMIZATION-IF-TRUE*/
+        i = z[1]-'0';  /* The common case of ?N for a single digit N */
+        bOk = 1;
+      }else{
+        bOk = 0==sqlite3Atoi64(&z[1], &i, n-1, SQLITE_UTF8);
+      }
+      testcase( i==0 );
+      testcase( i==1 );
+      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
+      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
+      if( bOk==0 || i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+        sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
+            db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
+        sqlite3RecordErrorOffsetOfExpr(pParse->db, pExpr);
+        return;
+      }
+      x = (ynVar)i;
+      if( x>pParse->nVar ){
+        pParse->nVar = (int)x;
+        doAdd = 1;
+      }else if( sqlite3VListNumToName(pParse->pVList, x)==0 ){
+        doAdd = 1;
+      }
+    }else{
+      /* Wildcards like ":aaa", "$aaa" or "@aaa".  Reuse the same variable
+      ** number as the prior appearance of the same name, or if the name
+      ** has never appeared before, reuse the same variable number
+      */
+      x = (ynVar)sqlite3VListNameToNum(pParse->pVList, z, n);
+      if( x==0 ){
+        x = (ynVar)(++pParse->nVar);
+        doAdd = 1;
+      }
+    }
+    if( doAdd ){
+      pParse->pVList = sqlite3VListAdd(db, pParse->pVList, z, n, x);
+    }
+  }
+  pExpr->iColumn = x;
+  if( x>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+    sqlite3ErrorMsg(pParse, "too many SQL variables");
+    sqlite3RecordErrorOffsetOfExpr(pParse->db, pExpr);
+  }
+}
+
+/*
+** Recursively delete an expression tree.
+*/
+static SQLITE_NOINLINE void sqlite3ExprDeleteNN(sqlite3 *db, Expr *p){
+  assert( p!=0 );
+  assert( db!=0 );
+exprDeleteRestart:
+  assert( !ExprUseUValue(p) || p->u.iValue>=0 );
+  assert( !ExprUseYWin(p) || !ExprUseYSub(p) );
+  assert( !ExprUseYWin(p) || p->y.pWin!=0 || db->mallocFailed );
+  assert( p->op!=TK_FUNCTION || !ExprUseYSub(p) );
+#ifdef SQLITE_DEBUG
+  if( ExprHasProperty(p, EP_Leaf) && !ExprHasProperty(p, EP_TokenOnly) ){
+    assert( p->pLeft==0 );
+    assert( p->pRight==0 );
+    assert( !ExprUseXSelect(p) || p->x.pSelect==0 );
+    assert( !ExprUseXList(p) || p->x.pList==0 );
+  }
+#endif
+  if( !ExprHasProperty(p, (EP_TokenOnly|EP_Leaf)) ){
+    /* The Expr.x union is never used at the same time as Expr.pRight */
+    assert( (ExprUseXList(p) && p->x.pList==0) || p->pRight==0 );
+    if( p->pRight ){
+      assert( !ExprHasProperty(p, EP_WinFunc) );
+      sqlite3ExprDeleteNN(db, p->pRight);
+    }else if( ExprUseXSelect(p) ){
+      assert( !ExprHasProperty(p, EP_WinFunc) );
+      sqlite3SelectDelete(db, p->x.pSelect);
+    }else{
+      sqlite3ExprListDelete(db, p->x.pList);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( ExprHasProperty(p, EP_WinFunc) ){
+        sqlite3WindowDelete(db, p->y.pWin);
+      }
+#endif
+    }
+    if( p->pLeft && p->op!=TK_SELECT_COLUMN ){
+      Expr *pLeft = p->pLeft;
+      if( !ExprHasProperty(p, EP_Static)
+       && !ExprHasProperty(pLeft, EP_Static)
+      ){
+        /* Avoid unnecessary recursion on unary operators */
+        sqlite3DbNNFreeNN(db, p);
+        p = pLeft;
+        goto exprDeleteRestart;
+      }else{
+        sqlite3ExprDeleteNN(db, pLeft);
+      }
+    }
+  }
+  if( !ExprHasProperty(p, EP_Static) ){
+    sqlite3DbNNFreeNN(db, p);
+  }
+}
+SQLITE_PRIVATE void sqlite3ExprDelete(sqlite3 *db, Expr *p){
+  if( p ) sqlite3ExprDeleteNN(db, p);
+}
+SQLITE_PRIVATE void sqlite3ExprDeleteGeneric(sqlite3 *db, void *p){
+  if( ALWAYS(p) ) sqlite3ExprDeleteNN(db, (Expr*)p);
+}
+
+/*
+** Clear both elements of an OnOrUsing object
+*/
+SQLITE_PRIVATE void sqlite3ClearOnOrUsing(sqlite3 *db, OnOrUsing *p){
+  if( p==0 ){
+    /* Nothing to clear */
+  }else if( p->pOn ){
+    sqlite3ExprDeleteNN(db, p->pOn);
+  }else if( p->pUsing ){
+    sqlite3IdListDelete(db, p->pUsing);
+  }
+}
+
+/*
+** Arrange to cause pExpr to be deleted when the pParse is deleted.
+** This is similar to sqlite3ExprDelete() except that the delete is
+** deferred until the pParse is deleted.
+**
+** The pExpr might be deleted immediately on an OOM error.
+**
+** Return 0 if the delete was successfully deferred.  Return non-zero
+** if the delete happened immediately because of an OOM.
+*/
+SQLITE_PRIVATE int sqlite3ExprDeferredDelete(Parse *pParse, Expr *pExpr){
+  return 0==sqlite3ParserAddCleanup(pParse, sqlite3ExprDeleteGeneric, pExpr);
+}
+
+/* Invoke sqlite3RenameExprUnmap() and sqlite3ExprDelete() on the
+** expression.
+*/
+SQLITE_PRIVATE void sqlite3ExprUnmapAndDelete(Parse *pParse, Expr *p){
+  if( p ){
+    if( IN_RENAME_OBJECT ){
+      sqlite3RenameExprUnmap(pParse, p);
+    }
+    sqlite3ExprDeleteNN(pParse->db, p);
+  }
+}
+
+/*
+** Return the number of bytes allocated for the expression structure
+** passed as the first argument. This is always one of EXPR_FULLSIZE,
+** EXPR_REDUCEDSIZE or EXPR_TOKENONLYSIZE.
+*/
+static int exprStructSize(const Expr *p){
+  if( ExprHasProperty(p, EP_TokenOnly) ) return EXPR_TOKENONLYSIZE;
+  if( ExprHasProperty(p, EP_Reduced) ) return EXPR_REDUCEDSIZE;
+  return EXPR_FULLSIZE;
+}
+
+/*
+** The dupedExpr*Size() routines each return the number of bytes required
+** to store a copy of an expression or expression tree.  They differ in
+** how much of the tree is measured.
+**
+**     dupedExprStructSize()     Size of only the Expr structure
+**     dupedExprNodeSize()       Size of Expr + space for token
+**     dupedExprSize()           Expr + token + subtree components
+**
+***************************************************************************
+**
+** The dupedExprStructSize() function returns two values OR-ed together:
+** (1) the space required for a copy of the Expr structure only and
+** (2) the EP_xxx flags that indicate what the structure size should be.
+** The return values is always one of:
+**
+**      EXPR_FULLSIZE
+**      EXPR_REDUCEDSIZE   | EP_Reduced
+**      EXPR_TOKENONLYSIZE | EP_TokenOnly
+**
+** The size of the structure can be found by masking the return value
+** of this routine with 0xfff.  The flags can be found by masking the
+** return value with EP_Reduced|EP_TokenOnly.
+**
+** Note that with flags==EXPRDUP_REDUCE, this routines works on full-size
+** (unreduced) Expr objects as they or originally constructed by the parser.
+** During expression analysis, extra information is computed and moved into
+** later parts of the Expr object and that extra information might get chopped
+** off if the expression is reduced.  Note also that it does not work to
+** make an EXPRDUP_REDUCE copy of a reduced expression.  It is only legal
+** to reduce a pristine expression tree from the parser.  The implementation
+** of dupedExprStructSize() contain multiple assert() statements that attempt
+** to enforce this constraint.
+*/
+static int dupedExprStructSize(const Expr *p, int flags){
+  int nSize;
+  assert( flags==EXPRDUP_REDUCE || flags==0 ); /* Only one flag value allowed */
+  assert( EXPR_FULLSIZE<=0xfff );
+  assert( (0xfff & (EP_Reduced|EP_TokenOnly))==0 );
+  if( 0==flags || ExprHasProperty(p, EP_FullSize) ){
+    nSize = EXPR_FULLSIZE;
+  }else{
+    assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
+    assert( !ExprHasProperty(p, EP_OuterON) );
+    assert( !ExprHasVVAProperty(p, EP_NoReduce) );
+    if( p->pLeft || p->x.pList ){
+      nSize = EXPR_REDUCEDSIZE | EP_Reduced;
+    }else{
+      assert( p->pRight==0 );
+      nSize = EXPR_TOKENONLYSIZE | EP_TokenOnly;
+    }
+  }
+  return nSize;
+}
+
+/*
+** This function returns the space in bytes required to store the copy
+** of the Expr structure and a copy of the Expr.u.zToken string (if that
+** string is defined.)
+*/
+static int dupedExprNodeSize(const Expr *p, int flags){
+  int nByte = dupedExprStructSize(p, flags) & 0xfff;
+  if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+    nByte += sqlite3Strlen30NN(p->u.zToken)+1;
+  }
+  return ROUND8(nByte);
+}
+
+/*
+** Return the number of bytes required to create a duplicate of the
+** expression passed as the first argument.
+**
+** The value returned includes space to create a copy of the Expr struct
+** itself and the buffer referred to by Expr.u.zToken, if any.
+**
+** The return value includes space to duplicate all Expr nodes in the
+** tree formed by Expr.pLeft and Expr.pRight, but not any other
+** substructure such as Expr.x.pList, Expr.x.pSelect, and Expr.y.pWin.
+*/
+static int dupedExprSize(const Expr *p){
+  int nByte;
+  assert( p!=0 );
+  nByte = dupedExprNodeSize(p, EXPRDUP_REDUCE);
+  if( p->pLeft ) nByte += dupedExprSize(p->pLeft);
+  if( p->pRight ) nByte += dupedExprSize(p->pRight);
+  assert( nByte==ROUND8(nByte) );
+  return nByte;
+}
+
+/*
+** An EdupBuf is a memory allocation used to stored multiple Expr objects
+** together with their Expr.zToken content.  This is used to help implement
+** compression while doing sqlite3ExprDup().  The top-level Expr does the
+** allocation for itself and many of its decendents, then passes an instance
+** of the structure down into exprDup() so that they decendents can have
+** access to that memory.
+*/
+typedef struct EdupBuf EdupBuf;
+struct EdupBuf {
+  u8 *zAlloc;          /* Memory space available for storage */
+#ifdef SQLITE_DEBUG
+  u8 *zEnd;            /* First byte past the end of memory */
+#endif
+};
+
+/*
+** This function is similar to sqlite3ExprDup(), except that if pEdupBuf
+** is not NULL then it points to memory that can be used to store a copy
+** of the input Expr p together with its p->u.zToken (if any).  pEdupBuf
+** is updated with the new buffer tail prior to returning.
+*/
+static Expr *exprDup(
+  sqlite3 *db,          /* Database connection (for memory allocation) */
+  const Expr *p,        /* Expr tree to be duplicated */
+  int dupFlags,         /* EXPRDUP_REDUCE for compression.  0 if not */
+  EdupBuf *pEdupBuf     /* Preallocated storage space, or NULL */
+){
+  Expr *pNew;           /* Value to return */
+  EdupBuf sEdupBuf;     /* Memory space from which to build Expr object */
+  u32 staticFlag;       /* EP_Static if space not obtained from malloc */
+  int nToken = -1;       /* Space needed for p->u.zToken.  -1 means unknown */
+
+  assert( db!=0 );
+  assert( p );
+  assert( dupFlags==0 || dupFlags==EXPRDUP_REDUCE );
+  assert( pEdupBuf==0 || dupFlags==EXPRDUP_REDUCE );
+
+  /* Figure out where to write the new Expr structure. */
+  if( pEdupBuf ){
+    sEdupBuf.zAlloc = pEdupBuf->zAlloc;
+#ifdef SQLITE_DEBUG
+    sEdupBuf.zEnd = pEdupBuf->zEnd;
+#endif
+    staticFlag = EP_Static;
+    assert( sEdupBuf.zAlloc!=0 );
+    assert( dupFlags==EXPRDUP_REDUCE );
+  }else{
+    int nAlloc;
+    if( dupFlags ){
+      nAlloc = dupedExprSize(p);
+    }else if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+      nToken = sqlite3Strlen30NN(p->u.zToken)+1;
+      nAlloc = ROUND8(EXPR_FULLSIZE + nToken);
+    }else{
+      nToken = 0;
+      nAlloc = ROUND8(EXPR_FULLSIZE);
+    }
+    assert( nAlloc==ROUND8(nAlloc) );
+    sEdupBuf.zAlloc = sqlite3DbMallocRawNN(db, nAlloc);
+#ifdef SQLITE_DEBUG
+    sEdupBuf.zEnd = sEdupBuf.zAlloc ? sEdupBuf.zAlloc+nAlloc : 0;
+#endif
+
+    staticFlag = 0;
+  }
+  pNew = (Expr *)sEdupBuf.zAlloc;
+  assert( EIGHT_BYTE_ALIGNMENT(pNew) );
+
+  if( pNew ){
+    /* Set nNewSize to the size allocated for the structure pointed to
+    ** by pNew. This is either EXPR_FULLSIZE, EXPR_REDUCEDSIZE or
+    ** EXPR_TOKENONLYSIZE. nToken is set to the number of bytes consumed
+    ** by the copy of the p->u.zToken string (if any).
+    */
+    const unsigned nStructSize = dupedExprStructSize(p, dupFlags);
+    int nNewSize = nStructSize & 0xfff;
+    if( nToken<0 ){
+      if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+        nToken = sqlite3Strlen30(p->u.zToken) + 1;
+      }else{
+        nToken = 0;
+      }
+    }
+    if( dupFlags ){
+      assert( (int)(sEdupBuf.zEnd - sEdupBuf.zAlloc) >= nNewSize+nToken );
+      assert( ExprHasProperty(p, EP_Reduced)==0 );
+      memcpy(sEdupBuf.zAlloc, p, nNewSize);
+    }else{
+      u32 nSize = (u32)exprStructSize(p);
+      assert( (int)(sEdupBuf.zEnd - sEdupBuf.zAlloc) >=
+                                                   (int)EXPR_FULLSIZE+nToken );
+      memcpy(sEdupBuf.zAlloc, p, nSize);
+      if( nSize<EXPR_FULLSIZE ){
+        memset(&sEdupBuf.zAlloc[nSize], 0, EXPR_FULLSIZE-nSize);
+      }
+      nNewSize = EXPR_FULLSIZE;
+    }
+
+    /* Set the EP_Reduced, EP_TokenOnly, and EP_Static flags appropriately. */
+    pNew->flags &= ~(EP_Reduced|EP_TokenOnly|EP_Static);
+    pNew->flags |= nStructSize & (EP_Reduced|EP_TokenOnly);
+    pNew->flags |= staticFlag;
+    ExprClearVVAProperties(pNew);
+    if( dupFlags ){
+      ExprSetVVAProperty(pNew, EP_Immutable);
+    }
+
+    /* Copy the p->u.zToken string, if any. */
+    assert( nToken>=0 );
+    if( nToken>0 ){
+      char *zToken = pNew->u.zToken = (char*)&sEdupBuf.zAlloc[nNewSize];
+      memcpy(zToken, p->u.zToken, nToken);
+      nNewSize += nToken;
+    }
+    sEdupBuf.zAlloc += ROUND8(nNewSize);
+
+    if( ((p->flags|pNew->flags)&(EP_TokenOnly|EP_Leaf))==0 ){
+
+      /* Fill in the pNew->x.pSelect or pNew->x.pList member. */
+      if( ExprUseXSelect(p) ){
+        pNew->x.pSelect = sqlite3SelectDup(db, p->x.pSelect, dupFlags);
+      }else{
+        pNew->x.pList = sqlite3ExprListDup(db, p->x.pList,
+                           p->op!=TK_ORDER ? dupFlags : 0);
+      }
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( ExprHasProperty(p, EP_WinFunc) ){
+        pNew->y.pWin = sqlite3WindowDup(db, pNew, p->y.pWin);
+        assert( ExprHasProperty(pNew, EP_WinFunc) );
+      }
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+      /* Fill in pNew->pLeft and pNew->pRight. */
+      if( dupFlags ){
+        if( p->op==TK_SELECT_COLUMN ){
+          pNew->pLeft = p->pLeft;
+          assert( p->pRight==0
+               || p->pRight==p->pLeft
+               || ExprHasProperty(p->pLeft, EP_Subquery) );
+        }else{
+          pNew->pLeft = p->pLeft ?
+                      exprDup(db, p->pLeft, EXPRDUP_REDUCE, &sEdupBuf) : 0;
+        }
+        pNew->pRight = p->pRight ?
+                       exprDup(db, p->pRight, EXPRDUP_REDUCE, &sEdupBuf) : 0;
+      }else{
+        if( p->op==TK_SELECT_COLUMN ){
+          pNew->pLeft = p->pLeft;
+          assert( p->pRight==0
+               || p->pRight==p->pLeft
+               || ExprHasProperty(p->pLeft, EP_Subquery) );
+        }else{
+          pNew->pLeft = sqlite3ExprDup(db, p->pLeft, 0);
+        }
+        pNew->pRight = sqlite3ExprDup(db, p->pRight, 0);
+      }
+    }
+  }
+  if( pEdupBuf ) memcpy(pEdupBuf, &sEdupBuf, sizeof(sEdupBuf));
+  assert( sEdupBuf.zAlloc <= sEdupBuf.zEnd );
+  return pNew;
+}
+
+/*
+** Create and return a deep copy of the object passed as the second
+** argument. If an OOM condition is encountered, NULL is returned
+** and the db->mallocFailed flag set.
+*/
+#ifndef SQLITE_OMIT_CTE
+SQLITE_PRIVATE With *sqlite3WithDup(sqlite3 *db, With *p){
+  With *pRet = 0;
+  if( p ){
+    sqlite3_int64 nByte = sizeof(*p) + sizeof(p->a[0]) * (p->nCte-1);
+    pRet = sqlite3DbMallocZero(db, nByte);
+    if( pRet ){
+      int i;
+      pRet->nCte = p->nCte;
+      for(i=0; i<p->nCte; i++){
+        pRet->a[i].pSelect = sqlite3SelectDup(db, p->a[i].pSelect, 0);
+        pRet->a[i].pCols = sqlite3ExprListDup(db, p->a[i].pCols, 0);
+        pRet->a[i].zName = sqlite3DbStrDup(db, p->a[i].zName);
+        pRet->a[i].eM10d = p->a[i].eM10d;
+      }
+    }
+  }
+  return pRet;
+}
+#else
+# define sqlite3WithDup(x,y) 0
+#endif
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** The gatherSelectWindows() procedure and its helper routine
+** gatherSelectWindowsCallback() are used to scan all the expressions
+** an a newly duplicated SELECT statement and gather all of the Window
+** objects found there, assembling them onto the linked list at Select->pWin.
+*/
+static int gatherSelectWindowsCallback(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_FUNCTION && ExprHasProperty(pExpr, EP_WinFunc) ){
+    Select *pSelect = pWalker->u.pSelect;
+    Window *pWin = pExpr->y.pWin;
+    assert( pWin );
+    assert( IsWindowFunc(pExpr) );
+    assert( pWin->ppThis==0 );
+    sqlite3WindowLink(pSelect, pWin);
+  }
+  return WRC_Continue;
+}
+static int gatherSelectWindowsSelectCallback(Walker *pWalker, Select *p){
+  return p==pWalker->u.pSelect ? WRC_Continue : WRC_Prune;
+}
+static void gatherSelectWindows(Select *p){
+  Walker w;
+  w.xExprCallback = gatherSelectWindowsCallback;
+  w.xSelectCallback = gatherSelectWindowsSelectCallback;
+  w.xSelectCallback2 = 0;
+  w.pParse = 0;
+  w.u.pSelect = p;
+  sqlite3WalkSelect(&w, p);
+}
+#endif
+
+
+/*
+** The following group of routines make deep copies of expressions,
+** expression lists, ID lists, and select statements.  The copies can
+** be deleted (by being passed to their respective ...Delete() routines)
+** without effecting the originals.
+**
+** The expression list, ID, and source lists return by sqlite3ExprListDup(),
+** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded
+** by subsequent calls to sqlite*ListAppend() routines.
+**
+** Any tables that the SrcList might point to are not duplicated.
+**
+** The flags parameter contains a combination of the EXPRDUP_XXX flags.
+** If the EXPRDUP_REDUCE flag is set, then the structure returned is a
+** truncated version of the usual Expr structure that will be stored as
+** part of the in-memory representation of the database schema.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3 *db, const Expr *p, int flags){
+  assert( flags==0 || flags==EXPRDUP_REDUCE );
+  return p ? exprDup(db, p, flags, 0) : 0;
+}
+SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3 *db, const ExprList *p, int flags){
+  ExprList *pNew;
+  struct ExprList_item *pItem;
+  const struct ExprList_item *pOldItem;
+  int i;
+  Expr *pPriorSelectColOld = 0;
+  Expr *pPriorSelectColNew = 0;
+  assert( db!=0 );
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRawNN(db, sqlite3DbMallocSize(db, p));
+  if( pNew==0 ) return 0;
+  pNew->nExpr = p->nExpr;
+  pNew->nAlloc = p->nAlloc;
+  pItem = pNew->a;
+  pOldItem = p->a;
+  for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
+    Expr *pOldExpr = pOldItem->pExpr;
+    Expr *pNewExpr;
+    pItem->pExpr = sqlite3ExprDup(db, pOldExpr, flags);
+    if( pOldExpr
+     && pOldExpr->op==TK_SELECT_COLUMN
+     && (pNewExpr = pItem->pExpr)!=0
+    ){
+      if( pNewExpr->pRight ){
+        pPriorSelectColOld = pOldExpr->pRight;
+        pPriorSelectColNew = pNewExpr->pRight;
+        pNewExpr->pLeft = pNewExpr->pRight;
+      }else{
+        if( pOldExpr->pLeft!=pPriorSelectColOld ){
+          pPriorSelectColOld = pOldExpr->pLeft;
+          pPriorSelectColNew = sqlite3ExprDup(db, pPriorSelectColOld, flags);
+          pNewExpr->pRight = pPriorSelectColNew;
+        }
+        pNewExpr->pLeft = pPriorSelectColNew;
+      }
+    }
+    pItem->zEName = sqlite3DbStrDup(db, pOldItem->zEName);
+    pItem->fg = pOldItem->fg;
+    pItem->fg.done = 0;
+    pItem->u = pOldItem->u;
+  }
+  return pNew;
+}
+
+/*
+** If cursors, triggers, views and subqueries are all omitted from
+** the build, then none of the following routines, except for
+** sqlite3SelectDup(), can be called. sqlite3SelectDup() is sometimes
+** called with a NULL argument.
+*/
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
+ || !defined(SQLITE_OMIT_SUBQUERY)
+SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
+  SrcList *pNew;
+  int i;
+  int nByte;
+  assert( db!=0 );
+  if( p==0 ) return 0;
+  nByte = sizeof(*p) + (p->nSrc>0 ? sizeof(p->a[0]) * (p->nSrc-1) : 0);
+  pNew = sqlite3DbMallocRawNN(db, nByte );
+  if( pNew==0 ) return 0;
+  pNew->nSrc = pNew->nAlloc = p->nSrc;
+  for(i=0; i<p->nSrc; i++){
+    SrcItem *pNewItem = &pNew->a[i];
+    const SrcItem *pOldItem = &p->a[i];
+    Table *pTab;
+    pNewItem->fg = pOldItem->fg;
+    if( pOldItem->fg.isSubquery ){
+      Subquery *pNewSubq = sqlite3DbMallocRaw(db, sizeof(Subquery));
+      if( pNewSubq==0 ){
+        assert( db->mallocFailed );
+        pNewItem->fg.isSubquery = 0;
+      }else{
+        memcpy(pNewSubq, pOldItem->u4.pSubq, sizeof(*pNewSubq));
+        pNewSubq->pSelect = sqlite3SelectDup(db, pNewSubq->pSelect, flags);
+        if( pNewSubq->pSelect==0 ){
+          sqlite3DbFree(db, pNewSubq);
+          pNewSubq = 0;
+          pNewItem->fg.isSubquery = 0;
+        }
+      }
+      pNewItem->u4.pSubq = pNewSubq;
+    }else if( pOldItem->fg.fixedSchema ){
+      pNewItem->u4.pSchema = pOldItem->u4.pSchema;
+    }else{
+      pNewItem->u4.zDatabase = sqlite3DbStrDup(db, pOldItem->u4.zDatabase);
+    }
+    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
+    pNewItem->iCursor = pOldItem->iCursor;
+    if( pNewItem->fg.isIndexedBy ){
+      pNewItem->u1.zIndexedBy = sqlite3DbStrDup(db, pOldItem->u1.zIndexedBy);
+    }else if( pNewItem->fg.isTabFunc ){
+      pNewItem->u1.pFuncArg =
+          sqlite3ExprListDup(db, pOldItem->u1.pFuncArg, flags);
+    }else{
+      pNewItem->u1.nRow = pOldItem->u1.nRow;
+    }
+    pNewItem->u2 = pOldItem->u2;
+    if( pNewItem->fg.isCte ){
+      pNewItem->u2.pCteUse->nUse++;
+    }
+    pTab = pNewItem->pSTab = pOldItem->pSTab;
+    if( pTab ){
+      pTab->nTabRef++;
+    }
+    if( pOldItem->fg.isUsing ){
+      assert( pNewItem->fg.isUsing );
+      pNewItem->u3.pUsing = sqlite3IdListDup(db, pOldItem->u3.pUsing);
+    }else{
+      pNewItem->u3.pOn = sqlite3ExprDup(db, pOldItem->u3.pOn, flags);
+    }
+    pNewItem->colUsed = pOldItem->colUsed;
+  }
+  return pNew;
+}
+SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3 *db, const IdList *p){
+  IdList *pNew;
+  int i;
+  assert( db!=0 );
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRawNN(db, sizeof(*pNew)+(p->nId-1)*sizeof(p->a[0]) );
+  if( pNew==0 ) return 0;
+  pNew->nId = p->nId;
+  for(i=0; i<p->nId; i++){
+    struct IdList_item *pNewItem = &pNew->a[i];
+    const struct IdList_item *pOldItem = &p->a[i];
+    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+  }
+  return pNew;
+}
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, const Select *pDup, int flags){
+  Select *pRet = 0;
+  Select *pNext = 0;
+  Select **pp = &pRet;
+  const Select *p;
+
+  assert( db!=0 );
+  for(p=pDup; p; p=p->pPrior){
+    Select *pNew = sqlite3DbMallocRawNN(db, sizeof(*p) );
+    if( pNew==0 ) break;
+    pNew->pEList = sqlite3ExprListDup(db, p->pEList, flags);
+    pNew->pSrc = sqlite3SrcListDup(db, p->pSrc, flags);
+    pNew->pWhere = sqlite3ExprDup(db, p->pWhere, flags);
+    pNew->pGroupBy = sqlite3ExprListDup(db, p->pGroupBy, flags);
+    pNew->pHaving = sqlite3ExprDup(db, p->pHaving, flags);
+    pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy, flags);
+    pNew->op = p->op;
+    pNew->pNext = pNext;
+    pNew->pPrior = 0;
+    pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
+    pNew->iLimit = 0;
+    pNew->iOffset = 0;
+    pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
+    pNew->addrOpenEphm[0] = -1;
+    pNew->addrOpenEphm[1] = -1;
+    pNew->nSelectRow = p->nSelectRow;
+    pNew->pWith = sqlite3WithDup(db, p->pWith);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    pNew->pWin = 0;
+    pNew->pWinDefn = sqlite3WindowListDup(db, p->pWinDefn);
+    if( p->pWin && db->mallocFailed==0 ) gatherSelectWindows(pNew);
+#endif
+    pNew->selId = p->selId;
+    if( db->mallocFailed ){
+      /* Any prior OOM might have left the Select object incomplete.
+      ** Delete the whole thing rather than allow an incomplete Select
+      ** to be used by the code generator. */
+      pNew->pNext = 0;
+      sqlite3SelectDelete(db, pNew);
+      break;
+    }
+    *pp = pNew;
+    pp = &pNew->pPrior;
+    pNext = pNew;
+  }
+  return pRet;
+}
+#else
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, const Select *p, int flags){
+  assert( p==0 );
+  return 0;
+}
+#endif
+
+
+/*
+** Add a new element to the end of an expression list.  If pList is
+** initially NULL, then create a new expression list.
+**
+** The pList argument must be either NULL or a pointer to an ExprList
+** obtained from a prior call to sqlite3ExprListAppend().
+**
+** If a memory allocation error occurs, the entire list is freed and
+** NULL is returned.  If non-NULL is returned, then it is guaranteed
+** that the new entry was successfully appended.
+*/
+static const struct ExprList_item zeroItem = {0};
+SQLITE_PRIVATE SQLITE_NOINLINE ExprList *sqlite3ExprListAppendNew(
+  sqlite3 *db,            /* Database handle.  Used for memory allocation */
+  Expr *pExpr             /* Expression to be appended. Might be NULL */
+){
+  struct ExprList_item *pItem;
+  ExprList *pList;
+
+  pList = sqlite3DbMallocRawNN(db, sizeof(ExprList)+sizeof(pList->a[0])*4 );
+  if( pList==0 ){
+    sqlite3ExprDelete(db, pExpr);
+    return 0;
+  }
+  pList->nAlloc = 4;
+  pList->nExpr = 1;
+  pItem = &pList->a[0];
+  *pItem = zeroItem;
+  pItem->pExpr = pExpr;
+  return pList;
+}
+SQLITE_PRIVATE SQLITE_NOINLINE ExprList *sqlite3ExprListAppendGrow(
+  sqlite3 *db,            /* Database handle.  Used for memory allocation */
+  ExprList *pList,        /* List to which to append. Might be NULL */
+  Expr *pExpr             /* Expression to be appended. Might be NULL */
+){
+  struct ExprList_item *pItem;
+  ExprList *pNew;
+  pList->nAlloc *= 2;
+  pNew = sqlite3DbRealloc(db, pList,
+       sizeof(*pList)+(pList->nAlloc-1)*sizeof(pList->a[0]));
+  if( pNew==0 ){
+    sqlite3ExprListDelete(db, pList);
+    sqlite3ExprDelete(db, pExpr);
+    return 0;
+  }else{
+    pList = pNew;
+  }
+  pItem = &pList->a[pList->nExpr++];
+  *pItem = zeroItem;
+  pItem->pExpr = pExpr;
+  return pList;
+}
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to append. Might be NULL */
+  Expr *pExpr             /* Expression to be appended. Might be NULL */
+){
+  struct ExprList_item *pItem;
+  if( pList==0 ){
+    return sqlite3ExprListAppendNew(pParse->db,pExpr);
+  }
+  if( pList->nAlloc<pList->nExpr+1 ){
+    return sqlite3ExprListAppendGrow(pParse->db,pList,pExpr);
+  }
+  pItem = &pList->a[pList->nExpr++];
+  *pItem = zeroItem;
+  pItem->pExpr = pExpr;
+  return pList;
+}
+
+/*
+** pColumns and pExpr form a vector assignment which is part of the SET
+** clause of an UPDATE statement.  Like this:
+**
+**        (a,b,c) = (expr1,expr2,expr3)
+** Or:    (a,b,c) = (SELECT x,y,z FROM ....)
+**
+** For each term of the vector assignment, append new entries to the
+** expression list pList.  In the case of a subquery on the RHS, append
+** TK_SELECT_COLUMN expressions.
+*/
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppendVector(
+  Parse *pParse,         /* Parsing context */
+  ExprList *pList,       /* List to which to append. Might be NULL */
+  IdList *pColumns,      /* List of names of LHS of the assignment */
+  Expr *pExpr            /* Vector expression to be appended. Might be NULL */
+){
+  sqlite3 *db = pParse->db;
+  int n;
+  int i;
+  int iFirst = pList ? pList->nExpr : 0;
+  /* pColumns can only be NULL due to an OOM but an OOM will cause an
+  ** exit prior to this routine being invoked */
+  if( NEVER(pColumns==0) ) goto vector_append_error;
+  if( pExpr==0 ) goto vector_append_error;
+
+  /* If the RHS is a vector, then we can immediately check to see that
+  ** the size of the RHS and LHS match.  But if the RHS is a SELECT,
+  ** wildcards ("*") in the result set of the SELECT must be expanded before
+  ** we can do the size check, so defer the size check until code generation.
+  */
+  if( pExpr->op!=TK_SELECT && pColumns->nId!=(n=sqlite3ExprVectorSize(pExpr)) ){
+    sqlite3ErrorMsg(pParse, "%d columns assigned %d values",
+                    pColumns->nId, n);
+    goto vector_append_error;
+  }
+
+  for(i=0; i<pColumns->nId; i++){
+    Expr *pSubExpr = sqlite3ExprForVectorField(pParse, pExpr, i, pColumns->nId);
+    assert( pSubExpr!=0 || db->mallocFailed );
+    if( pSubExpr==0 ) continue;
+    pList = sqlite3ExprListAppend(pParse, pList, pSubExpr);
+    if( pList ){
+      assert( pList->nExpr==iFirst+i+1 );
+      pList->a[pList->nExpr-1].zEName = pColumns->a[i].zName;
+      pColumns->a[i].zName = 0;
+    }
+  }
+
+  if( !db->mallocFailed && pExpr->op==TK_SELECT && ALWAYS(pList!=0) ){
+    Expr *pFirst = pList->a[iFirst].pExpr;
+    assert( pFirst!=0 );
+    assert( pFirst->op==TK_SELECT_COLUMN );
+
+    /* Store the SELECT statement in pRight so it will be deleted when
+    ** sqlite3ExprListDelete() is called */
+    pFirst->pRight = pExpr;
+    pExpr = 0;
+
+    /* Remember the size of the LHS in iTable so that we can check that
+    ** the RHS and LHS sizes match during code generation. */
+    pFirst->iTable = pColumns->nId;
+  }
+
+vector_append_error:
+  sqlite3ExprUnmapAndDelete(pParse, pExpr);
+  sqlite3IdListDelete(db, pColumns);
+  return pList;
+}
+
+/*
+** Set the sort order for the last element on the given ExprList.
+*/
+SQLITE_PRIVATE void sqlite3ExprListSetSortOrder(ExprList *p, int iSortOrder, int eNulls){
+  struct ExprList_item *pItem;
+  if( p==0 ) return;
+  assert( p->nExpr>0 );
+
+  assert( SQLITE_SO_UNDEFINED<0 && SQLITE_SO_ASC==0 && SQLITE_SO_DESC>0 );
+  assert( iSortOrder==SQLITE_SO_UNDEFINED
+       || iSortOrder==SQLITE_SO_ASC
+       || iSortOrder==SQLITE_SO_DESC
+  );
+  assert( eNulls==SQLITE_SO_UNDEFINED
+       || eNulls==SQLITE_SO_ASC
+       || eNulls==SQLITE_SO_DESC
+  );
+
+  pItem = &p->a[p->nExpr-1];
+  assert( pItem->fg.bNulls==0 );
+  if( iSortOrder==SQLITE_SO_UNDEFINED ){
+    iSortOrder = SQLITE_SO_ASC;
+  }
+  pItem->fg.sortFlags = (u8)iSortOrder;
+
+  if( eNulls!=SQLITE_SO_UNDEFINED ){
+    pItem->fg.bNulls = 1;
+    if( iSortOrder!=eNulls ){
+      pItem->fg.sortFlags |= KEYINFO_ORDER_BIGNULL;
+    }
+  }
+}
+
+/*
+** Set the ExprList.a[].zEName element of the most recently added item
+** on the expression list.
+**
+** pList might be NULL following an OOM error.  But pName should never be
+** NULL.  If a memory allocation fails, the pParse->db->mallocFailed flag
+** is set.
+*/
+SQLITE_PRIVATE void sqlite3ExprListSetName(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to add the span. */
+  const Token *pName,     /* Name to be added */
+  int dequote             /* True to cause the name to be dequoted */
+){
+  assert( pList!=0 || pParse->db->mallocFailed!=0 );
+  assert( pParse->eParseMode!=PARSE_MODE_UNMAP || dequote==0 );
+  if( pList ){
+    struct ExprList_item *pItem;
+    assert( pList->nExpr>0 );
+    pItem = &pList->a[pList->nExpr-1];
+    assert( pItem->zEName==0 );
+    assert( pItem->fg.eEName==ENAME_NAME );
+    pItem->zEName = sqlite3DbStrNDup(pParse->db, pName->z, pName->n);
+    if( dequote ){
+      /* If dequote==0, then pName->z does not point to part of a DDL
+      ** statement handled by the parser. And so no token need be added
+      ** to the token-map.  */
+      sqlite3Dequote(pItem->zEName);
+      if( IN_RENAME_OBJECT ){
+        sqlite3RenameTokenMap(pParse, (const void*)pItem->zEName, pName);
+      }
+    }
+  }
+}
+
+/*
+** Set the ExprList.a[].zSpan element of the most recently added item
+** on the expression list.
+**
+** pList might be NULL following an OOM error.  But pSpan should never be
+** NULL.  If a memory allocation fails, the pParse->db->mallocFailed flag
+** is set.
+*/
+SQLITE_PRIVATE void sqlite3ExprListSetSpan(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to add the span. */
+  const char *zStart,     /* Start of the span */
+  const char *zEnd        /* End of the span */
+){
+  sqlite3 *db = pParse->db;
+  assert( pList!=0 || db->mallocFailed!=0 );
+  if( pList ){
+    struct ExprList_item *pItem = &pList->a[pList->nExpr-1];
+    assert( pList->nExpr>0 );
+    if( pItem->zEName==0 ){
+      pItem->zEName = sqlite3DbSpanDup(db, zStart, zEnd);
+      pItem->fg.eEName = ENAME_SPAN;
+    }
+  }
+}
+
+/*
+** If the expression list pEList contains more than iLimit elements,
+** leave an error message in pParse.
+*/
+SQLITE_PRIVATE void sqlite3ExprListCheckLength(
+  Parse *pParse,
+  ExprList *pEList,
+  const char *zObject
+){
+  int mx = pParse->db->aLimit[SQLITE_LIMIT_COLUMN];
+  testcase( pEList && pEList->nExpr==mx );
+  testcase( pEList && pEList->nExpr==mx+1 );
+  if( pEList && pEList->nExpr>mx ){
+    sqlite3ErrorMsg(pParse, "too many columns in %s", zObject);
+  }
+}
+
+/*
+** Delete an entire expression list.
+*/
+static SQLITE_NOINLINE void exprListDeleteNN(sqlite3 *db, ExprList *pList){
+  int i = pList->nExpr;
+  struct ExprList_item *pItem =  pList->a;
+  assert( pList->nExpr>0 );
+  assert( db!=0 );
+  do{
+    sqlite3ExprDelete(db, pItem->pExpr);
+    if( pItem->zEName ) sqlite3DbNNFreeNN(db, pItem->zEName);
+    pItem++;
+  }while( --i>0 );
+  sqlite3DbNNFreeNN(db, pList);
+}
+SQLITE_PRIVATE void sqlite3ExprListDelete(sqlite3 *db, ExprList *pList){
+  if( pList ) exprListDeleteNN(db, pList);
+}
+SQLITE_PRIVATE void sqlite3ExprListDeleteGeneric(sqlite3 *db, void *pList){
+  if( ALWAYS(pList) ) exprListDeleteNN(db, (ExprList*)pList);
+}
+
+/*
+** Return the bitwise-OR of all Expr.flags fields in the given
+** ExprList.
+*/
+SQLITE_PRIVATE u32 sqlite3ExprListFlags(const ExprList *pList){
+  int i;
+  u32 m = 0;
+  assert( pList!=0 );
+  for(i=0; i<pList->nExpr; i++){
+     Expr *pExpr = pList->a[i].pExpr;
+     assert( pExpr!=0 );
+     m |= pExpr->flags;
+  }
+  return m;
+}
+
+/*
+** This is a SELECT-node callback for the expression walker that
+** always "fails".  By "fail" in this case, we mean set
+** pWalker->eCode to zero and abort.
+**
+** This callback is used by multiple expression walkers.
+*/
+SQLITE_PRIVATE int sqlite3SelectWalkFail(Walker *pWalker, Select *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  pWalker->eCode = 0;
+  return WRC_Abort;
+}
+
+/*
+** Check the input string to see if it is "true" or "false" (in any case).
+**
+**       If the string is....           Return
+**         "true"                         EP_IsTrue
+**         "false"                        EP_IsFalse
+**         anything else                  0
+*/
+SQLITE_PRIVATE u32 sqlite3IsTrueOrFalse(const char *zIn){
+  if( sqlite3StrICmp(zIn, "true")==0  ) return EP_IsTrue;
+  if( sqlite3StrICmp(zIn, "false")==0 ) return EP_IsFalse;
+  return 0;
+}
+
+
+/*
+** If the input expression is an ID with the name "true" or "false"
+** then convert it into an TK_TRUEFALSE term.  Return non-zero if
+** the conversion happened, and zero if the expression is unaltered.
+*/
+SQLITE_PRIVATE int sqlite3ExprIdToTrueFalse(Expr *pExpr){
+  u32 v;
+  assert( pExpr->op==TK_ID || pExpr->op==TK_STRING );
+  if( !ExprHasProperty(pExpr, EP_Quoted|EP_IntValue)
+   && (v = sqlite3IsTrueOrFalse(pExpr->u.zToken))!=0
+  ){
+    pExpr->op = TK_TRUEFALSE;
+    ExprSetProperty(pExpr, v);
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** The argument must be a TK_TRUEFALSE Expr node.  Return 1 if it is TRUE
+** and 0 if it is FALSE.
+*/
+SQLITE_PRIVATE int sqlite3ExprTruthValue(const Expr *pExpr){
+  pExpr = sqlite3ExprSkipCollateAndLikely((Expr*)pExpr);
+  assert( pExpr->op==TK_TRUEFALSE );
+  assert( !ExprHasProperty(pExpr, EP_IntValue) );
+  assert( sqlite3StrICmp(pExpr->u.zToken,"true")==0
+       || sqlite3StrICmp(pExpr->u.zToken,"false")==0 );
+  return pExpr->u.zToken[4]==0;
+}
+
+/*
+** If pExpr is an AND or OR expression, try to simplify it by eliminating
+** terms that are always true or false.  Return the simplified expression.
+** Or return the original expression if no simplification is possible.
+**
+** Examples:
+**
+**     (x<10) AND true                =>   (x<10)
+**     (x<10) AND false               =>   false
+**     (x<10) AND (y=22 OR false)     =>   (x<10) AND (y=22)
+**     (x<10) AND (y=22 OR true)      =>   (x<10)
+**     (y=22) OR true                 =>   true
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprSimplifiedAndOr(Expr *pExpr){
+  assert( pExpr!=0 );
+  if( pExpr->op==TK_AND || pExpr->op==TK_OR ){
+    Expr *pRight = sqlite3ExprSimplifiedAndOr(pExpr->pRight);
+    Expr *pLeft = sqlite3ExprSimplifiedAndOr(pExpr->pLeft);
+    if( ExprAlwaysTrue(pLeft) || ExprAlwaysFalse(pRight) ){
+      pExpr = pExpr->op==TK_AND ? pRight : pLeft;
+    }else if( ExprAlwaysTrue(pRight) || ExprAlwaysFalse(pLeft) ){
+      pExpr = pExpr->op==TK_AND ? pLeft : pRight;
+    }
+  }
+  return pExpr;
+}
+
+/*
+** pExpr is a TK_FUNCTION node.  Try to determine whether or not the
+** function is a constant function.  A function is constant if all of
+** the following are true:
+**
+**    (1)  It is a scalar function (not an aggregate or window function)
+**    (2)  It has either the SQLITE_FUNC_CONSTANT or SQLITE_FUNC_SLOCHNG
+**         property.
+**    (3)  All of its arguments are constants
+**
+** This routine sets pWalker->eCode to 0 if pExpr is not a constant.
+** It makes no changes to pWalker->eCode if pExpr is constant.  In
+** every case, it returns WRC_Abort.
+**
+** Called as a service subroutine from exprNodeIsConstant().
+*/
+static SQLITE_NOINLINE int exprNodeIsConstantFunction(
+  Walker *pWalker,
+  Expr *pExpr
+){
+  int n;             /* Number of arguments */
+  ExprList *pList;   /* List of arguments */
+  FuncDef *pDef;     /* The function */
+  sqlite3 *db;       /* The database */
+
+  assert( pExpr->op==TK_FUNCTION );
+  if( ExprHasProperty(pExpr, EP_TokenOnly)
+   || (pList = pExpr->x.pList)==0
+  ){;
+    n = 0;
+  }else{
+    n = pList->nExpr;
+    sqlite3WalkExprList(pWalker, pList);
+    if( pWalker->eCode==0 ) return WRC_Abort;
+  }
+  db = pWalker->pParse->db;
+  pDef = sqlite3FindFunction(db, pExpr->u.zToken, n, ENC(db), 0);
+  if( pDef==0
+   || pDef->xFinalize!=0
+   || (pDef->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG))==0
+   || ExprHasProperty(pExpr, EP_WinFunc)
+  ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+  return WRC_Prune;
+}
+
+
+/*
+** These routines are Walker callbacks used to check expressions to
+** see if they are "constant" for some definition of constant.  The
+** Walker.eCode value determines the type of "constant" we are looking
+** for.
+**
+** These callback routines are used to implement the following:
+**
+**     sqlite3ExprIsConstant()                  pWalker->eCode==1
+**     sqlite3ExprIsConstantNotJoin()           pWalker->eCode==2
+**     sqlite3ExprIsTableConstant()             pWalker->eCode==3
+**     sqlite3ExprIsConstantOrFunction()        pWalker->eCode==4 or 5
+**
+** In all cases, the callbacks set Walker.eCode=0 and abort if the expression
+** is found to not be a constant.
+**
+** The sqlite3ExprIsConstantOrFunction() is used for evaluating DEFAULT
+** expressions in a CREATE TABLE statement.  The Walker.eCode value is 5
+** when parsing an existing schema out of the sqlite_schema table and 4
+** when processing a new CREATE TABLE statement.  A bound parameter raises
+** an error for new statements, but is silently converted
+** to NULL for existing schemas.  This allows sqlite_schema tables that
+** contain a bound parameter because they were generated by older versions
+** of SQLite to be parsed by newer versions of SQLite without raising a
+** malformed schema error.
+*/
+static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){
+  assert( pWalker->eCode>0 );
+
+  /* If pWalker->eCode is 2 then any term of the expression that comes from
+  ** the ON or USING clauses of an outer join disqualifies the expression
+  ** from being considered constant. */
+  if( pWalker->eCode==2 && ExprHasProperty(pExpr, EP_OuterON) ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+
+  switch( pExpr->op ){
+    /* Consider functions to be constant if all their arguments are constant
+    ** and either pWalker->eCode==4 or 5 or the function has the
+    ** SQLITE_FUNC_CONST flag. */
+    case TK_FUNCTION:
+      if( (pWalker->eCode>=4 || ExprHasProperty(pExpr,EP_ConstFunc))
+       && !ExprHasProperty(pExpr, EP_WinFunc)
+      ){
+        if( pWalker->eCode==5 ) ExprSetProperty(pExpr, EP_FromDDL);
+        return WRC_Continue;
+      }else if( pWalker->pParse ){
+        return exprNodeIsConstantFunction(pWalker, pExpr);
+      }else{
+        pWalker->eCode = 0;
+        return WRC_Abort;
+      }
+    case TK_ID:
+      /* Convert "true" or "false" in a DEFAULT clause into the
+      ** appropriate TK_TRUEFALSE operator */
+      if( sqlite3ExprIdToTrueFalse(pExpr) ){
+        return WRC_Prune;
+      }
+      /* no break */ deliberate_fall_through
+    case TK_COLUMN:
+    case TK_AGG_FUNCTION:
+    case TK_AGG_COLUMN:
+      testcase( pExpr->op==TK_ID );
+      testcase( pExpr->op==TK_COLUMN );
+      testcase( pExpr->op==TK_AGG_FUNCTION );
+      testcase( pExpr->op==TK_AGG_COLUMN );
+      if( ExprHasProperty(pExpr, EP_FixedCol) && pWalker->eCode!=2 ){
+        return WRC_Continue;
+      }
+      if( pWalker->eCode==3 && pExpr->iTable==pWalker->u.iCur ){
+        return WRC_Continue;
+      }
+      /* no break */ deliberate_fall_through
+    case TK_IF_NULL_ROW:
+    case TK_REGISTER:
+    case TK_DOT:
+    case TK_RAISE:
+      testcase( pExpr->op==TK_REGISTER );
+      testcase( pExpr->op==TK_IF_NULL_ROW );
+      testcase( pExpr->op==TK_DOT );
+      testcase( pExpr->op==TK_RAISE );
+      pWalker->eCode = 0;
+      return WRC_Abort;
+    case TK_VARIABLE:
+      if( pWalker->eCode==5 ){
+        /* Silently convert bound parameters that appear inside of CREATE
+        ** statements into a NULL when parsing the CREATE statement text out
+        ** of the sqlite_schema table */
+        pExpr->op = TK_NULL;
+      }else if( pWalker->eCode==4 ){
+        /* A bound parameter in a CREATE statement that originates from
+        ** sqlite3_prepare() causes an error */
+        pWalker->eCode = 0;
+        return WRC_Abort;
+      }
+      /* no break */ deliberate_fall_through
+    default:
+      testcase( pExpr->op==TK_SELECT ); /* sqlite3SelectWalkFail() disallows */
+      testcase( pExpr->op==TK_EXISTS ); /* sqlite3SelectWalkFail() disallows */
+      return WRC_Continue;
+  }
+}
+static int exprIsConst(Parse *pParse, Expr *p, int initFlag){
+  Walker w;
+  w.eCode = initFlag;
+  w.pParse = pParse;
+  w.xExprCallback = exprNodeIsConstant;
+  w.xSelectCallback = sqlite3SelectWalkFail;
+#ifdef SQLITE_DEBUG
+  w.xSelectCallback2 = sqlite3SelectWalkAssert2;
+#endif
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+/*
+** Walk an expression tree.  Return non-zero if the expression is constant
+** and 0 if it involves variables or function calls.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+**
+** The pParse parameter may be NULL.  But if it is NULL, there is no way
+** to determine if function calls are constant or not, and hence all
+** function calls will be considered to be non-constant.  If pParse is
+** not NULL, then a function call might be constant, depending on the
+** function and on its parameters.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsConstant(Parse *pParse, Expr *p){
+  return exprIsConst(pParse, p, 1);
+}
+
+/*
+** Walk an expression tree.  Return non-zero if
+**
+**   (1) the expression is constant, and
+**   (2) the expression does originate in the ON or USING clause
+**       of a LEFT JOIN, and
+**   (3) the expression does not contain any EP_FixedCol TK_COLUMN
+**       operands created by the constant propagation optimization.
+**
+** When this routine returns true, it indicates that the expression
+** can be added to the pParse->pConstExpr list and evaluated once when
+** the prepared statement starts up.  See sqlite3ExprCodeRunJustOnce().
+*/
+static int sqlite3ExprIsConstantNotJoin(Parse *pParse, Expr *p){
+  return exprIsConst(pParse, p, 2);
+}
+
+/*
+** This routine examines sub-SELECT statements as an expression is being
+** walked as part of sqlite3ExprIsTableConstant().  Sub-SELECTs are considered
+** constant as long as they are uncorrelated - meaning that they do not
+** contain any terms from outer contexts.
+*/
+static int exprSelectWalkTableConstant(Walker *pWalker, Select *pSelect){
+  assert( pSelect!=0 );
+  assert( pWalker->eCode==3 || pWalker->eCode==0 );
+  if( (pSelect->selFlags & SF_Correlated)!=0 ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+  return WRC_Prune;
+}
+
+/*
+** Walk an expression tree.  Return non-zero if the expression is constant
+** for any single row of the table with cursor iCur.  In other words, the
+** expression must not refer to any non-deterministic function nor any
+** table other than iCur.
+**
+** Consider uncorrelated subqueries to be constants if the bAllowSubq
+** parameter is true.
+*/
+static int sqlite3ExprIsTableConstant(Expr *p, int iCur, int bAllowSubq){
+  Walker w;
+  w.eCode = 3;
+  w.pParse = 0;
+  w.xExprCallback = exprNodeIsConstant;
+  if( bAllowSubq ){
+    w.xSelectCallback = exprSelectWalkTableConstant;
+  }else{
+    w.xSelectCallback = sqlite3SelectWalkFail;
+#ifdef SQLITE_DEBUG
+    w.xSelectCallback2 = sqlite3SelectWalkAssert2;
+#endif
+  }
+  w.u.iCur = iCur;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+/*
+** Check pExpr to see if it is an constraint on the single data source
+** pSrc = &pSrcList->a[iSrc].  In other words, check to see if pExpr
+** constrains pSrc but does not depend on any other tables or data
+** sources anywhere else in the query.  Return true (non-zero) if pExpr
+** is a constraint on pSrc only.
+**
+** This is an optimization.  False negatives will perhaps cause slower
+** queries, but false positives will yield incorrect answers.  So when in
+** doubt, return 0.
+**
+** To be an single-source constraint, the following must be true:
+**
+**   (1)  pExpr cannot refer to any table other than pSrc->iCursor.
+**
+**   (2a) pExpr cannot use subqueries unless the bAllowSubq parameter is
+**        true and the subquery is non-correlated
+**
+**   (2b) pExpr cannot use non-deterministic functions.
+**
+**   (3)  pSrc cannot be part of the left operand for a RIGHT JOIN.
+**        (Is there some way to relax this constraint?)
+**
+**   (4)  If pSrc is the right operand of a LEFT JOIN, then...
+**         (4a)  pExpr must come from an ON clause..
+**         (4b)  and specifically the ON clause associated with the LEFT JOIN.
+**
+**   (5)  If pSrc is the right operand of a LEFT JOIN or the left
+**        operand of a RIGHT JOIN, then pExpr must be from the WHERE
+**        clause, not an ON clause.
+**
+**   (6) Either:
+**
+**       (6a) pExpr does not originate in an ON or USING clause, or
+**
+**       (6b) The ON or USING clause from which pExpr is derived is
+**            not to the left of a RIGHT JOIN (or FULL JOIN).
+**
+**       Without this restriction, accepting pExpr as a single-table
+**       constraint might move the the ON/USING filter expression
+**       from the left side of a RIGHT JOIN over to the right side,
+**       which leads to incorrect answers.  See also restriction (9)
+**       on push-down.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsSingleTableConstraint(
+  Expr *pExpr,                 /* The constraint */
+  const SrcList *pSrcList,     /* Complete FROM clause */
+  int iSrc,                    /* Which element of pSrcList to use */
+  int bAllowSubq               /* Allow non-correlated subqueries */
+){
+  const SrcItem *pSrc = &pSrcList->a[iSrc];
+  if( pSrc->fg.jointype & JT_LTORJ ){
+    return 0;  /* rule (3) */
+  }
+  if( pSrc->fg.jointype & JT_LEFT ){
+    if( !ExprHasProperty(pExpr, EP_OuterON) ) return 0;   /* rule (4a) */
+    if( pExpr->w.iJoin!=pSrc->iCursor ) return 0;         /* rule (4b) */
+  }else{
+    if( ExprHasProperty(pExpr, EP_OuterON) ) return 0;    /* rule (5) */
+  }
+  if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON)  /* (6a) */
+   && (pSrcList->a[0].fg.jointype & JT_LTORJ)!=0     /* Fast pre-test of (6b) */
+  ){
+    int jj;
+    for(jj=0; jj<iSrc; jj++){
+      if( pExpr->w.iJoin==pSrcList->a[jj].iCursor ){
+        if( (pSrcList->a[jj].fg.jointype & JT_LTORJ)!=0 ){
+          return 0;  /* restriction (6) */
+        }
+        break;
+      }
+    }
+  }
+  /* Rules (1), (2a), and (2b) handled by the following: */
+  return sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor, bAllowSubq);
+}
+
+
+/*
+** sqlite3WalkExpr() callback used by sqlite3ExprIsConstantOrGroupBy().
+*/
+static int exprNodeIsConstantOrGroupBy(Walker *pWalker, Expr *pExpr){
+  ExprList *pGroupBy = pWalker->u.pGroupBy;
+  int i;
+
+  /* Check if pExpr is identical to any GROUP BY term. If so, consider
+  ** it constant.  */
+  for(i=0; i<pGroupBy->nExpr; i++){
+    Expr *p = pGroupBy->a[i].pExpr;
+    if( sqlite3ExprCompare(0, pExpr, p, -1)<2 ){
+      CollSeq *pColl = sqlite3ExprNNCollSeq(pWalker->pParse, p);
+      if( sqlite3IsBinary(pColl) ){
+        return WRC_Prune;
+      }
+    }
+  }
+
+  /* Check if pExpr is a sub-select. If so, consider it variable. */
+  if( ExprUseXSelect(pExpr) ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+
+  return exprNodeIsConstant(pWalker, pExpr);
+}
+
+/*
+** Walk the expression tree passed as the first argument. Return non-zero
+** if the expression consists entirely of constants or copies of terms
+** in pGroupBy that sort with the BINARY collation sequence.
+**
+** This routine is used to determine if a term of the HAVING clause can
+** be promoted into the WHERE clause.  In order for such a promotion to work,
+** the value of the HAVING clause term must be the same for all members of
+** a "group".  The requirement that the GROUP BY term must be BINARY
+** assumes that no other collating sequence will have a finer-grained
+** grouping than binary.  In other words (A=B COLLATE binary) implies
+** A=B in every other collating sequence.  The requirement that the
+** GROUP BY be BINARY is stricter than necessary.  It would also work
+** to promote HAVING clauses that use the same alternative collating
+** sequence as the GROUP BY term, but that is much harder to check,
+** alternative collating sequences are uncommon, and this is only an
+** optimization, so we take the easy way out and simply require the
+** GROUP BY to use the BINARY collating sequence.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrGroupBy(Parse *pParse, Expr *p, ExprList *pGroupBy){
+  Walker w;
+  w.eCode = 1;
+  w.xExprCallback = exprNodeIsConstantOrGroupBy;
+  w.xSelectCallback = 0;
+  w.u.pGroupBy = pGroupBy;
+  w.pParse = pParse;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+/*
+** Walk an expression tree for the DEFAULT field of a column definition
+** in a CREATE TABLE statement.  Return non-zero if the expression is
+** acceptable for use as a DEFAULT.  That is to say, return non-zero if
+** the expression is constant or a function call with constant arguments.
+** Return and 0 if there are any variables.
+**
+** isInit is true when parsing from sqlite_schema.  isInit is false when
+** processing a new CREATE TABLE statement.  When isInit is true, parameters
+** (such as ? or $abc) in the expression are converted into NULL.  When
+** isInit is false, parameters raise an error.  Parameters should not be
+** allowed in a CREATE TABLE statement, but some legacy versions of SQLite
+** allowed it, so we need to support it when reading sqlite_schema for
+** backwards compatibility.
+**
+** If isInit is true, set EP_FromDDL on every TK_FUNCTION node.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr *p, u8 isInit){
+  assert( isInit==0 || isInit==1 );
+  return exprIsConst(0, p, 4+isInit);
+}
+
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/*
+** Walk an expression tree.  Return 1 if the expression contains a
+** subquery of some kind.  Return 0 if there are no subqueries.
+*/
+SQLITE_PRIVATE int sqlite3ExprContainsSubquery(Expr *p){
+  Walker w;
+  w.eCode = 1;
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.xSelectCallback = sqlite3SelectWalkFail;
+#ifdef SQLITE_DEBUG
+  w.xSelectCallback2 = sqlite3SelectWalkAssert2;
+#endif
+  sqlite3WalkExpr(&w, p);
+  return w.eCode==0;
+}
+#endif
+
+/*
+** If the expression p codes a constant integer that is small enough
+** to fit in a 32-bit integer, return 1 and put the value of the integer
+** in *pValue.  If the expression is not an integer or if it is too big
+** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
+**
+** If the pParse pointer is provided, then allow the expression p to be
+** a parameter (TK_VARIABLE) that is bound to an integer.
+** But if pParse is NULL, then p must be a pure integer literal.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsInteger(const Expr *p, int *pValue, Parse *pParse){
+  int rc = 0;
+  if( NEVER(p==0) ) return 0;  /* Used to only happen following on OOM */
+
+  /* If an expression is an integer literal that fits in a signed 32-bit
+  ** integer, then the EP_IntValue flag will have already been set */
+  assert( p->op!=TK_INTEGER || (p->flags & EP_IntValue)!=0
+           || sqlite3GetInt32(p->u.zToken, &rc)==0 );
+
+  if( p->flags & EP_IntValue ){
+    *pValue = p->u.iValue;
+    return 1;
+  }
+  switch( p->op ){
+    case TK_UPLUS: {
+      rc = sqlite3ExprIsInteger(p->pLeft, pValue, 0);
+      break;
+    }
+    case TK_UMINUS: {
+      int v = 0;
+      if( sqlite3ExprIsInteger(p->pLeft, &v, 0) ){
+        assert( ((unsigned int)v)!=0x80000000 );
+        *pValue = -v;
+        rc = 1;
+      }
+      break;
+    }
+    case TK_VARIABLE: {
+      sqlite3_value *pVal;
+      if( pParse==0 ) break;
+      if( NEVER(pParse->pVdbe==0) ) break;
+      if( (pParse->db->flags & SQLITE_EnableQPSG)!=0 ) break;
+      sqlite3VdbeSetVarmask(pParse->pVdbe, p->iColumn);
+      pVal = sqlite3VdbeGetBoundValue(pParse->pReprepare, p->iColumn,
+                                      SQLITE_AFF_BLOB);
+      if( pVal ){
+        if( sqlite3_value_type(pVal)==SQLITE_INTEGER ){
+          sqlite3_int64 vv = sqlite3_value_int64(pVal);
+          if( vv == (vv & 0x7fffffff) ){ /* non-negative numbers only */
+            *pValue = (int)vv;
+            rc = 1;
+          }
+        }
+        sqlite3ValueFree(pVal);
+      }
+      break;
+    }
+    default: break;
+  }
+  return rc;
+}
+
+/*
+** Return FALSE if there is no chance that the expression can be NULL.
+**
+** If the expression might be NULL or if the expression is too complex
+** to tell return TRUE.
+**
+** This routine is used as an optimization, to skip OP_IsNull opcodes
+** when we know that a value cannot be NULL.  Hence, a false positive
+** (returning TRUE when in fact the expression can never be NULL) might
+** be a small performance hit but is otherwise harmless.  On the other
+** hand, a false negative (returning FALSE when the result could be NULL)
+** will likely result in an incorrect answer.  So when in doubt, return
+** TRUE.
+*/
+SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr *p){
+  u8 op;
+  assert( p!=0 );
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){
+    p = p->pLeft;
+    assert( p!=0 );
+  }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER:
+    case TK_STRING:
+    case TK_FLOAT:
+    case TK_BLOB:
+      return 0;
+    case TK_COLUMN:
+      assert( ExprUseYTab(p) );
+      return ExprHasProperty(p, EP_CanBeNull)
+          || NEVER(p->y.pTab==0) /* Reference to column of index on expr */
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+          || (p->iColumn==XN_ROWID && IsView(p->y.pTab))
+#endif
+          || (p->iColumn>=0
+              && p->y.pTab->aCol!=0 /* Possible due to prior error */
+              && ALWAYS(p->iColumn<p->y.pTab->nCol)
+              && p->y.pTab->aCol[p->iColumn].notNull==0);
+    default:
+      return 1;
+  }
+}
+
+/*
+** Return TRUE if the given expression is a constant which would be
+** unchanged by OP_Affinity with the affinity given in the second
+** argument.
+**
+** This routine is used to determine if the OP_Affinity operation
+** can be omitted.  When in doubt return FALSE.  A false negative
+** is harmless.  A false positive, however, can result in the wrong
+** answer.
+*/
+SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr *p, char aff){
+  u8 op;
+  int unaryMinus = 0;
+  if( aff==SQLITE_AFF_BLOB ) return 1;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){
+    if( p->op==TK_UMINUS ) unaryMinus = 1;
+    p = p->pLeft;
+  }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER: {
+      return aff>=SQLITE_AFF_NUMERIC;
+    }
+    case TK_FLOAT: {
+      return aff>=SQLITE_AFF_NUMERIC;
+    }
+    case TK_STRING: {
+      return !unaryMinus && aff==SQLITE_AFF_TEXT;
+    }
+    case TK_BLOB: {
+      return !unaryMinus;
+    }
+    case TK_COLUMN: {
+      assert( p->iTable>=0 );  /* p cannot be part of a CHECK constraint */
+      return aff>=SQLITE_AFF_NUMERIC && p->iColumn<0;
+    }
+    default: {
+      return 0;
+    }
+  }
+}
+
+/*
+** Return TRUE if the given string is a row-id column name.
+*/
+SQLITE_PRIVATE int sqlite3IsRowid(const char *z){
+  if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1;
+  if( sqlite3StrICmp(z, "ROWID")==0 ) return 1;
+  if( sqlite3StrICmp(z, "OID")==0 ) return 1;
+  return 0;
+}
+
+/*
+** Return a pointer to a buffer containing a usable rowid alias for table
+** pTab. An alias is usable if there is not an explicit user-defined column
+** of the same name.
+*/
+SQLITE_PRIVATE const char *sqlite3RowidAlias(Table *pTab){
+  const char *azOpt[] = {"_ROWID_", "ROWID", "OID"};
+  int ii;
+  assert( VisibleRowid(pTab) );
+  for(ii=0; ii<ArraySize(azOpt); ii++){
+    int iCol;
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      if( sqlite3_stricmp(azOpt[ii], pTab->aCol[iCol].zCnName)==0 ) break;
+    }
+    if( iCol==pTab->nCol ){
+      return azOpt[ii];
+    }
+  }
+  return 0;
+}
+
+/*
+** pX is the RHS of an IN operator.  If pX is a SELECT statement
+** that can be simplified to a direct table access, then return
+** a pointer to the SELECT statement.  If pX is not a SELECT statement,
+** or if the SELECT statement needs to be materialized into a transient
+** table, then return NULL.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+static Select *isCandidateForInOpt(const Expr *pX){
+  Select *p;
+  SrcList *pSrc;
+  ExprList *pEList;
+  Table *pTab;
+  int i;
+  if( !ExprUseXSelect(pX) ) return 0;                 /* Not a subquery */
+  if( ExprHasProperty(pX, EP_VarSelect)  ) return 0;  /* Correlated subq */
+  p = pX->x.pSelect;
+  if( p->pPrior ) return 0;              /* Not a compound SELECT */
+  if( p->selFlags & (SF_Distinct|SF_Aggregate) ){
+    testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
+    testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
+    return 0; /* No DISTINCT keyword and no aggregate functions */
+  }
+  assert( p->pGroupBy==0 );              /* Has no GROUP BY clause */
+  if( p->pLimit ) return 0;              /* Has no LIMIT clause */
+  if( p->pWhere ) return 0;              /* Has no WHERE clause */
+  pSrc = p->pSrc;
+  assert( pSrc!=0 );
+  if( pSrc->nSrc!=1 ) return 0;          /* Single term in FROM clause */
+  if( pSrc->a[0].fg.isSubquery) return 0;/* FROM is not a subquery or view */
+  pTab = pSrc->a[0].pSTab;
+  assert( pTab!=0 );
+  assert( !IsView(pTab)  );              /* FROM clause is not a view */
+  if( IsVirtual(pTab) ) return 0;        /* FROM clause not a virtual table */
+  pEList = p->pEList;
+  assert( pEList!=0 );
+  /* All SELECT results must be columns. */
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *pRes = pEList->a[i].pExpr;
+    if( pRes->op!=TK_COLUMN ) return 0;
+    assert( pRes->iTable==pSrc->a[0].iCursor );  /* Not a correlated subquery */
+  }
+  return p;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code that checks the left-most column of index table iCur to see if
+** it contains any NULL entries.  Cause the register at regHasNull to be set
+** to a non-NULL value if iCur contains no NULLs.  Cause register regHasNull
+** to be set to NULL if iCur contains one or more NULL values.
+*/
+static void sqlite3SetHasNullFlag(Vdbe *v, int iCur, int regHasNull){
+  int addr1;
+  sqlite3VdbeAddOp2(v, OP_Integer, 0, regHasNull);
+  addr1 = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
+  sqlite3VdbeAddOp3(v, OP_Column, iCur, 0, regHasNull);
+  sqlite3VdbeChangeP5(v, OPFLAG_TYPEOFARG);
+  VdbeComment((v, "first_entry_in(%d)", iCur));
+  sqlite3VdbeJumpHere(v, addr1);
+}
+#endif
+
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** The argument is an IN operator with a list (not a subquery) on the
+** right-hand side.  Return TRUE if that list is constant.
+*/
+static int sqlite3InRhsIsConstant(Parse *pParse, Expr *pIn){
+  Expr *pLHS;
+  int res;
+  assert( !ExprHasProperty(pIn, EP_xIsSelect) );
+  pLHS = pIn->pLeft;
+  pIn->pLeft = 0;
+  res = sqlite3ExprIsConstant(pParse, pIn);
+  pIn->pLeft = pLHS;
+  return res;
+}
+#endif
+
+/*
+** This function is used by the implementation of the IN (...) operator.
+** The pX parameter is the expression on the RHS of the IN operator, which
+** might be either a list of expressions or a subquery.
+**
+** The job of this routine is to find or create a b-tree object that can
+** be used either to test for membership in the RHS set or to iterate through
+** all members of the RHS set, skipping duplicates.
+**
+** A cursor is opened on the b-tree object that is the RHS of the IN operator
+** and the *piTab parameter is set to the index of that cursor.
+**
+** The returned value of this function indicates the b-tree type, as follows:
+**
+**   IN_INDEX_ROWID      - The cursor was opened on a database table.
+**   IN_INDEX_INDEX_ASC  - The cursor was opened on an ascending index.
+**   IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
+**   IN_INDEX_EPH        - The cursor was opened on a specially created and
+**                         populated ephemeral table.
+**   IN_INDEX_NOOP       - No cursor was allocated.  The IN operator must be
+**                         implemented as a sequence of comparisons.
+**
+** An existing b-tree might be used if the RHS expression pX is a simple
+** subquery such as:
+**
+**     SELECT <column1>, <column2>... FROM <table>
+**
+** If the RHS of the IN operator is a list or a more complex subquery, then
+** an ephemeral table might need to be generated from the RHS and then
+** pX->iTable made to point to the ephemeral table instead of an
+** existing table.  In this case, the creation and initialization of the
+** ephemeral table might be put inside of a subroutine, the EP_Subrtn flag
+** will be set on pX and the pX->y.sub fields will be set to show where
+** the subroutine is coded.
+**
+** The inFlags parameter must contain, at a minimum, one of the bits
+** IN_INDEX_MEMBERSHIP or IN_INDEX_LOOP but not both.  If inFlags contains
+** IN_INDEX_MEMBERSHIP, then the generated table will be used for a fast
+** membership test.  When the IN_INDEX_LOOP bit is set, the IN index will
+** be used to loop over all values of the RHS of the IN operator.
+**
+** When IN_INDEX_LOOP is used (and the b-tree will be used to iterate
+** through the set members) then the b-tree must not contain duplicates.
+** An ephemeral table will be created unless the selected columns are guaranteed
+** to be unique - either because it is an INTEGER PRIMARY KEY or due to
+** a UNIQUE constraint or index.
+**
+** When IN_INDEX_MEMBERSHIP is used (and the b-tree will be used
+** for fast set membership tests) then an ephemeral table must
+** be used unless <columns> is a single INTEGER PRIMARY KEY column or an
+** index can be found with the specified <columns> as its left-most.
+**
+** If the IN_INDEX_NOOP_OK and IN_INDEX_MEMBERSHIP are both set and
+** if the RHS of the IN operator is a list (not a subquery) then this
+** routine might decide that creating an ephemeral b-tree for membership
+** testing is too expensive and return IN_INDEX_NOOP.  In that case, the
+** calling routine should implement the IN operator using a sequence
+** of Eq or Ne comparison operations.
+**
+** When the b-tree is being used for membership tests, the calling function
+** might need to know whether or not the RHS side of the IN operator
+** contains a NULL.  If prRhsHasNull is not a NULL pointer and
+** if there is any chance that the (...) might contain a NULL value at
+** runtime, then a register is allocated and the register number written
+** to *prRhsHasNull. If there is no chance that the (...) contains a
+** NULL value, then *prRhsHasNull is left unchanged.
+**
+** If a register is allocated and its location stored in *prRhsHasNull, then
+** the value in that register will be NULL if the b-tree contains one or more
+** NULL values, and it will be some non-NULL value if the b-tree contains no
+** NULL values.
+**
+** If the aiMap parameter is not NULL, it must point to an array containing
+** one element for each column returned by the SELECT statement on the RHS
+** of the IN(...) operator. The i'th entry of the array is populated with the
+** offset of the index column that matches the i'th column returned by the
+** SELECT. For example, if the expression and selected index are:
+**
+**   (?,?,?) IN (SELECT a, b, c FROM t1)
+**   CREATE INDEX i1 ON t1(b, c, a);
+**
+** then aiMap[] is populated with {2, 0, 1}.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+SQLITE_PRIVATE int sqlite3FindInIndex(
+  Parse *pParse,             /* Parsing context */
+  Expr *pX,                  /* The IN expression */
+  u32 inFlags,               /* IN_INDEX_LOOP, _MEMBERSHIP, and/or _NOOP_OK */
+  int *prRhsHasNull,         /* Register holding NULL status.  See notes */
+  int *aiMap,                /* Mapping from Index fields to RHS fields */
+  int *piTab                 /* OUT: index to use */
+){
+  Select *p;                            /* SELECT to the right of IN operator */
+  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
+  int iTab;                             /* Cursor of the RHS table */
+  int mustBeUnique;                     /* True if RHS must be unique */
+  Vdbe *v = sqlite3GetVdbe(pParse);     /* Virtual machine being coded */
+
+  assert( pX->op==TK_IN );
+  mustBeUnique = (inFlags & IN_INDEX_LOOP)!=0;
+  iTab = pParse->nTab++;
+
+  /* If the RHS of this IN(...) operator is a SELECT, and if it matters
+  ** whether or not the SELECT result contains NULL values, check whether
+  ** or not NULL is actually possible (it may not be, for example, due
+  ** to NOT NULL constraints in the schema). If no NULL values are possible,
+  ** set prRhsHasNull to 0 before continuing.  */
+  if( prRhsHasNull && ExprUseXSelect(pX) ){
+    int i;
+    ExprList *pEList = pX->x.pSelect->pEList;
+    for(i=0; i<pEList->nExpr; i++){
+      if( sqlite3ExprCanBeNull(pEList->a[i].pExpr) ) break;
+    }
+    if( i==pEList->nExpr ){
+      prRhsHasNull = 0;
+    }
+  }
+
+  /* Check to see if an existing table or index can be used to
+  ** satisfy the query.  This is preferable to generating a new
+  ** ephemeral table.  */
+  if( pParse->nErr==0 && (p = isCandidateForInOpt(pX))!=0 ){
+    sqlite3 *db = pParse->db;              /* Database connection */
+    Table *pTab;                           /* Table <table>. */
+    int iDb;                               /* Database idx for pTab */
+    ExprList *pEList = p->pEList;
+    int nExpr = pEList->nExpr;
+
+    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
+    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
+    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
+    pTab = p->pSrc->a[0].pSTab;
+
+    /* Code an OP_Transaction and OP_TableLock for <table>. */
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    assert( iDb>=0 && iDb<SQLITE_MAX_DB );
+    sqlite3CodeVerifySchema(pParse, iDb);
+    sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+
+    assert(v);  /* sqlite3GetVdbe() has always been previously called */
+    if( nExpr==1 && pEList->a[0].pExpr->iColumn<0 ){
+      /* The "x IN (SELECT rowid FROM table)" case */
+      int iAddr = sqlite3VdbeAddOp0(v, OP_Once);
+      VdbeCoverage(v);
+
+      sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
+      eType = IN_INDEX_ROWID;
+      ExplainQueryPlan((pParse, 0,
+            "USING ROWID SEARCH ON TABLE %s FOR IN-OPERATOR",pTab->zName));
+      sqlite3VdbeJumpHere(v, iAddr);
+    }else{
+      Index *pIdx;                         /* Iterator variable */
+      int affinity_ok = 1;
+      int i;
+
+      /* Check that the affinity that will be used to perform each
+      ** comparison is the same as the affinity of each column in table
+      ** on the RHS of the IN operator.  If it not, it is not possible to
+      ** use any index of the RHS table.  */
+      for(i=0; i<nExpr && affinity_ok; i++){
+        Expr *pLhs = sqlite3VectorFieldSubexpr(pX->pLeft, i);
+        int iCol = pEList->a[i].pExpr->iColumn;
+        char idxaff = sqlite3TableColumnAffinity(pTab,iCol); /* RHS table */
+        char cmpaff = sqlite3CompareAffinity(pLhs, idxaff);
+        testcase( cmpaff==SQLITE_AFF_BLOB );
+        testcase( cmpaff==SQLITE_AFF_TEXT );
+        switch( cmpaff ){
+          case SQLITE_AFF_BLOB:
+            break;
+          case SQLITE_AFF_TEXT:
+            /* sqlite3CompareAffinity() only returns TEXT if one side or the
+            ** other has no affinity and the other side is TEXT.  Hence,
+            ** the only way for cmpaff to be TEXT is for idxaff to be TEXT
+            ** and for the term on the LHS of the IN to have no affinity. */
+            assert( idxaff==SQLITE_AFF_TEXT );
+            break;
+          default:
+            affinity_ok = sqlite3IsNumericAffinity(idxaff);
+        }
+      }
+
+      if( affinity_ok ){
+        /* Search for an existing index that will work for this IN operator */
+        for(pIdx=pTab->pIndex; pIdx && eType==0; pIdx=pIdx->pNext){
+          Bitmask colUsed;      /* Columns of the index used */
+          Bitmask mCol;         /* Mask for the current column */
+          if( pIdx->nColumn<nExpr ) continue;
+          if( pIdx->pPartIdxWhere!=0 ) continue;
+          /* Maximum nColumn is BMS-2, not BMS-1, so that we can compute
+          ** BITMASK(nExpr) without overflowing */
+          testcase( pIdx->nColumn==BMS-2 );
+          testcase( pIdx->nColumn==BMS-1 );
+          if( pIdx->nColumn>=BMS-1 ) continue;
+          if( mustBeUnique ){
+            if( pIdx->nKeyCol>nExpr
+             ||(pIdx->nColumn>nExpr && !IsUniqueIndex(pIdx))
+            ){
+              continue;  /* This index is not unique over the IN RHS columns */
+            }
+          }
+
+          colUsed = 0;   /* Columns of index used so far */
+          for(i=0; i<nExpr; i++){
+            Expr *pLhs = sqlite3VectorFieldSubexpr(pX->pLeft, i);
+            Expr *pRhs = pEList->a[i].pExpr;
+            CollSeq *pReq = sqlite3BinaryCompareCollSeq(pParse, pLhs, pRhs);
+            int j;
+
+            for(j=0; j<nExpr; j++){
+              if( pIdx->aiColumn[j]!=pRhs->iColumn ) continue;
+              assert( pIdx->azColl[j] );
+              if( pReq!=0 && sqlite3StrICmp(pReq->zName, pIdx->azColl[j])!=0 ){
+                continue;
+              }
+              break;
+            }
+            if( j==nExpr ) break;
+            mCol = MASKBIT(j);
+            if( mCol & colUsed ) break; /* Each column used only once */
+            colUsed |= mCol;
+            if( aiMap ) aiMap[i] = j;
+          }
+
+          assert( nExpr>0 && nExpr<BMS );
+          assert( i==nExpr || colUsed!=(MASKBIT(nExpr)-1) );
+          if( colUsed==(MASKBIT(nExpr)-1) ){
+            /* If we reach this point, that means the index pIdx is usable */
+            int iAddr = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+            ExplainQueryPlan((pParse, 0,
+                              "USING INDEX %s FOR IN-OPERATOR",pIdx->zName));
+            sqlite3VdbeAddOp3(v, OP_OpenRead, iTab, pIdx->tnum, iDb);
+            sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+            VdbeComment((v, "%s", pIdx->zName));
+            assert( IN_INDEX_INDEX_DESC == IN_INDEX_INDEX_ASC+1 );
+            eType = IN_INDEX_INDEX_ASC + pIdx->aSortOrder[0];
+
+            if( prRhsHasNull ){
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+              i64 mask = (1<<nExpr)-1;
+              sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed,
+                  iTab, 0, 0, (u8*)&mask, P4_INT64);
+#endif
+              *prRhsHasNull = ++pParse->nMem;
+              if( nExpr==1 ){
+                sqlite3SetHasNullFlag(v, iTab, *prRhsHasNull);
+              }
+            }
+            sqlite3VdbeJumpHere(v, iAddr);
+          }
+        } /* End loop over indexes */
+      } /* End if( affinity_ok ) */
+    } /* End if not an rowid index */
+  } /* End attempt to optimize using an index */
+
+  /* If no preexisting index is available for the IN clause
+  ** and IN_INDEX_NOOP is an allowed reply
+  ** and the RHS of the IN operator is a list, not a subquery
+  ** and the RHS is not constant or has two or fewer terms,
+  ** then it is not worth creating an ephemeral table to evaluate
+  ** the IN operator so return IN_INDEX_NOOP.
+  */
+  if( eType==0
+   && (inFlags & IN_INDEX_NOOP_OK)
+   && ExprUseXList(pX)
+   && (!sqlite3InRhsIsConstant(pParse,pX) || pX->x.pList->nExpr<=2)
+  ){
+    pParse->nTab--;  /* Back out the allocation of the unused cursor */
+    iTab = -1;       /* Cursor is not allocated */
+    eType = IN_INDEX_NOOP;
+  }
+
+  if( eType==0 ){
+    /* Could not find an existing table or index to use as the RHS b-tree.
+    ** We will have to generate an ephemeral table to do the job.
+    */
+    u32 savedNQueryLoop = pParse->nQueryLoop;
+    int rMayHaveNull = 0;
+    eType = IN_INDEX_EPH;
+    if( inFlags & IN_INDEX_LOOP ){
+      pParse->nQueryLoop = 0;
+    }else if( prRhsHasNull ){
+      *prRhsHasNull = rMayHaveNull = ++pParse->nMem;
+    }
+    assert( pX->op==TK_IN );
+    sqlite3CodeRhsOfIN(pParse, pX, iTab);
+    if( rMayHaveNull ){
+      sqlite3SetHasNullFlag(v, iTab, rMayHaveNull);
+    }
+    pParse->nQueryLoop = savedNQueryLoop;
+  }
+
+  if( aiMap && eType!=IN_INDEX_INDEX_ASC && eType!=IN_INDEX_INDEX_DESC ){
+    int i, n;
+    n = sqlite3ExprVectorSize(pX->pLeft);
+    for(i=0; i<n; i++) aiMap[i] = i;
+  }
+  *piTab = iTab;
+  return eType;
+}
+#endif
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Argument pExpr is an (?, ?...) IN(...) expression. This
+** function allocates and returns a nul-terminated string containing
+** the affinities to be used for each column of the comparison.
+**
+** It is the responsibility of the caller to ensure that the returned
+** string is eventually freed using sqlite3DbFree().
+*/
+static char *exprINAffinity(Parse *pParse, const Expr *pExpr){
+  Expr *pLeft = pExpr->pLeft;
+  int nVal = sqlite3ExprVectorSize(pLeft);
+  Select *pSelect = ExprUseXSelect(pExpr) ? pExpr->x.pSelect : 0;
+  char *zRet;
+
+  assert( pExpr->op==TK_IN );
+  zRet = sqlite3DbMallocRaw(pParse->db, nVal+1);
+  if( zRet ){
+    int i;
+    for(i=0; i<nVal; i++){
+      Expr *pA = sqlite3VectorFieldSubexpr(pLeft, i);
+      char a = sqlite3ExprAffinity(pA);
+      if( pSelect ){
+        zRet[i] = sqlite3CompareAffinity(pSelect->pEList->a[i].pExpr, a);
+      }else{
+        zRet[i] = a;
+      }
+    }
+    zRet[nVal] = '\0';
+  }
+  return zRet;
+}
+#endif
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Load the Parse object passed as the first argument with an error
+** message of the form:
+**
+**   "sub-select returns N columns - expected M"
+*/
+SQLITE_PRIVATE void sqlite3SubselectError(Parse *pParse, int nActual, int nExpect){
+  if( pParse->nErr==0 ){
+    const char *zFmt = "sub-select returns %d columns - expected %d";
+    sqlite3ErrorMsg(pParse, zFmt, nActual, nExpect);
+  }
+}
+#endif
+
+/*
+** Expression pExpr is a vector that has been used in a context where
+** it is not permitted. If pExpr is a sub-select vector, this routine
+** loads the Parse object with a message of the form:
+**
+**   "sub-select returns N columns - expected 1"
+**
+** Or, if it is a regular scalar vector:
+**
+**   "row value misused"
+*/
+SQLITE_PRIVATE void sqlite3VectorErrorMsg(Parse *pParse, Expr *pExpr){
+#ifndef SQLITE_OMIT_SUBQUERY
+  if( ExprUseXSelect(pExpr) ){
+    sqlite3SubselectError(pParse, pExpr->x.pSelect->pEList->nExpr, 1);
+  }else
+#endif
+  {
+    sqlite3ErrorMsg(pParse, "row value misused");
+  }
+}
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Scan all previously generated bytecode looking for an OP_BeginSubrtn
+** that is compatible with pExpr.  If found, add the y.sub values
+** to pExpr and return true.  If not found, return false.
+*/
+static int findCompatibleInRhsSubrtn(
+  Parse *pParse,          /* Parsing context */
+  Expr *pExpr,            /* IN operator with RHS that we want to reuse */
+  SubrtnSig *pNewSig      /* Signature for the IN operator */
+){
+  VdbeOp *pOp, *pEnd;
+  SubrtnSig *pSig;
+  Vdbe *v;
+
+  if( pNewSig==0 ) return 0;
+  if( (pParse->mSubrtnSig & (1<<(pNewSig->selId&7)))==0 ) return 0;
+  assert( pExpr->op==TK_IN );
+  assert( !ExprUseYSub(pExpr) );
+  assert( ExprUseXSelect(pExpr) );
+  assert( pExpr->x.pSelect!=0 );
+  assert( (pExpr->x.pSelect->selFlags & SF_All)==0 );
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  pOp = sqlite3VdbeGetOp(v, 1);
+  pEnd = sqlite3VdbeGetLastOp(v);
+  for(; pOp<pEnd; pOp++){
+    if( pOp->p4type!=P4_SUBRTNSIG ) continue;
+    assert( pOp->opcode==OP_BeginSubrtn );
+    pSig = pOp->p4.pSubrtnSig;
+    assert( pSig!=0 );
+    if( !pSig->bComplete ) continue;
+    if( pNewSig->selId!=pSig->selId ) continue;
+    if( strcmp(pNewSig->zAff,pSig->zAff)!=0 ) continue;
+    pExpr->y.sub.iAddr = pSig->iAddr;
+    pExpr->y.sub.regReturn = pSig->regReturn;
+    pExpr->iTable = pSig->iTable;
+    ExprSetProperty(pExpr, EP_Subrtn);
+    return 1;
+  }
+  return 0;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code that will construct an ephemeral table containing all terms
+** in the RHS of an IN operator.  The IN operator can be in either of two
+** forms:
+**
+**     x IN (4,5,11)              -- IN operator with list on right-hand side
+**     x IN (SELECT a FROM b)     -- IN operator with subquery on the right
+**
+** The pExpr parameter is the IN operator.  The cursor number for the
+** constructed ephemeral table is returned.  The first time the ephemeral
+** table is computed, the cursor number is also stored in pExpr->iTable,
+** however the cursor number returned might not be the same, as it might
+** have been duplicated using OP_OpenDup.
+**
+** If the LHS expression ("x" in the examples) is a column value, or
+** the SELECT statement returns a column value, then the affinity of that
+** column is used to build the index keys. If both 'x' and the
+** SELECT... statement are columns, then numeric affinity is used
+** if either column has NUMERIC or INTEGER affinity. If neither
+** 'x' nor the SELECT... statement are columns, then numeric affinity
+** is used.
+*/
+SQLITE_PRIVATE void sqlite3CodeRhsOfIN(
+  Parse *pParse,          /* Parsing context */
+  Expr *pExpr,            /* The IN operator */
+  int iTab                /* Use this cursor number */
+){
+  int addrOnce = 0;           /* Address of the OP_Once instruction at top */
+  int addr;                   /* Address of OP_OpenEphemeral instruction */
+  Expr *pLeft;                /* the LHS of the IN operator */
+  KeyInfo *pKeyInfo = 0;      /* Key information */
+  int nVal;                   /* Size of vector pLeft */
+  Vdbe *v;                    /* The prepared statement under construction */
+  SubrtnSig *pSig = 0;        /* Signature for this subroutine */
+
+  v = pParse->pVdbe;
+  assert( v!=0 );
+
+  /* The evaluation of the IN must be repeated every time it
+  ** is encountered if any of the following is true:
+  **
+  **    *  The right-hand side is a correlated subquery
+  **    *  The right-hand side is an expression list containing variables
+  **    *  We are inside a trigger
+  **
+  ** If all of the above are false, then we can compute the RHS just once
+  ** and reuse it many names.
+  */
+  if( !ExprHasProperty(pExpr, EP_VarSelect) && pParse->iSelfTab==0 ){
+    /* Reuse of the RHS is allowed
+    **
+    ** Compute a signature for the RHS of the IN operator to facility
+    ** finding and reusing prior instances of the same IN operator.
+    */
+    assert( !ExprUseXSelect(pExpr) || pExpr->x.pSelect!=0 );
+    if( ExprUseXSelect(pExpr) && (pExpr->x.pSelect->selFlags & SF_All)==0 ){
+      pSig = sqlite3DbMallocRawNN(pParse->db, sizeof(pSig[0]));
+      if( pSig ){
+        pSig->selId = pExpr->x.pSelect->selId;
+        pSig->zAff = exprINAffinity(pParse, pExpr);
+      }
+    }
+
+    /* Check to see if there is a prior materialization of the RHS of
+    ** this IN operator.  If there is, then make use of that prior
+    ** materialization rather than recomputing it.
+    */
+    if( ExprHasProperty(pExpr, EP_Subrtn)
+     || findCompatibleInRhsSubrtn(pParse, pExpr, pSig)
+    ){
+      addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+      if( ExprUseXSelect(pExpr) ){
+        ExplainQueryPlan((pParse, 0, "REUSE LIST SUBQUERY %d",
+              pExpr->x.pSelect->selId));
+      }
+      assert( ExprUseYSub(pExpr) );
+      sqlite3VdbeAddOp2(v, OP_Gosub, pExpr->y.sub.regReturn,
+                        pExpr->y.sub.iAddr);
+      assert( iTab!=pExpr->iTable );
+      sqlite3VdbeAddOp2(v, OP_OpenDup, iTab, pExpr->iTable);
+      sqlite3VdbeJumpHere(v, addrOnce);
+      if( pSig ){
+        sqlite3DbFree(pParse->db, pSig->zAff);
+        sqlite3DbFree(pParse->db, pSig);
+      }
+      return;
+    }
+
+    /* Begin coding the subroutine */
+    assert( !ExprUseYWin(pExpr) );
+    ExprSetProperty(pExpr, EP_Subrtn);
+    assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+    pExpr->y.sub.regReturn = ++pParse->nMem;
+    pExpr->y.sub.iAddr =
+      sqlite3VdbeAddOp2(v, OP_BeginSubrtn, 0, pExpr->y.sub.regReturn) + 1;
+    if( pSig ){
+      pSig->bComplete = 0;
+      pSig->iAddr = pExpr->y.sub.iAddr;
+      pSig->regReturn = pExpr->y.sub.regReturn;
+      pSig->iTable = iTab;
+      pParse->mSubrtnSig = 1 << (pSig->selId&7);
+      sqlite3VdbeChangeP4(v, -1, (const char*)pSig, P4_SUBRTNSIG);
+    }
+    addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+  }
+
+  /* Check to see if this is a vector IN operator */
+  pLeft = pExpr->pLeft;
+  nVal = sqlite3ExprVectorSize(pLeft);
+
+  /* Construct the ephemeral table that will contain the content of
+  ** RHS of the IN operator.
+  */
+  pExpr->iTable = iTab;
+  addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pExpr->iTable, nVal);
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  if( ExprUseXSelect(pExpr) ){
+    VdbeComment((v, "Result of SELECT %u", pExpr->x.pSelect->selId));
+  }else{
+    VdbeComment((v, "RHS of IN operator"));
+  }
+#endif
+  pKeyInfo = sqlite3KeyInfoAlloc(pParse->db, nVal, 1);
+
+  if( ExprUseXSelect(pExpr) ){
+    /* Case 1:     expr IN (SELECT ...)
+    **
+    ** Generate code to write the results of the select into the temporary
+    ** table allocated and opened above.
+    */
+    Select *pSelect = pExpr->x.pSelect;
+    ExprList *pEList = pSelect->pEList;
+
+    ExplainQueryPlan((pParse, 1, "%sLIST SUBQUERY %d",
+        addrOnce?"":"CORRELATED ", pSelect->selId
+    ));
+    /* If the LHS and RHS of the IN operator do not match, that
+    ** error will have been caught long before we reach this point. */
+    if( ALWAYS(pEList->nExpr==nVal) ){
+      Select *pCopy;
+      SelectDest dest;
+      int i;
+      int rc;
+      int addrBloom = 0;
+      sqlite3SelectDestInit(&dest, SRT_Set, iTab);
+      dest.zAffSdst = exprINAffinity(pParse, pExpr);
+      pSelect->iLimit = 0;
+      if( addrOnce && OptimizationEnabled(pParse->db, SQLITE_BloomFilter) ){
+        int regBloom = ++pParse->nMem;
+        addrBloom = sqlite3VdbeAddOp2(v, OP_Blob, 10000, regBloom);
+        VdbeComment((v, "Bloom filter"));
+        dest.iSDParm2 = regBloom;
+      }
+      testcase( pSelect->selFlags & SF_Distinct );
+      testcase( pKeyInfo==0 ); /* Caused by OOM in sqlite3KeyInfoAlloc() */
+      pCopy = sqlite3SelectDup(pParse->db, pSelect, 0);
+      rc = pParse->db->mallocFailed ? 1 :sqlite3Select(pParse, pCopy, &dest);
+      sqlite3SelectDelete(pParse->db, pCopy);
+      sqlite3DbFree(pParse->db, dest.zAffSdst);
+      if( addrBloom ){
+        sqlite3VdbeGetOp(v, addrOnce)->p3 = dest.iSDParm2;
+        if( dest.iSDParm2==0 ){
+          sqlite3VdbeChangeToNoop(v, addrBloom);
+        }else{
+          sqlite3VdbeGetOp(v, addrOnce)->p3 = dest.iSDParm2;
+        }
+      }
+      if( rc ){
+        sqlite3KeyInfoUnref(pKeyInfo);
+        return;
+      }
+      assert( pKeyInfo!=0 ); /* OOM will cause exit after sqlite3Select() */
+      assert( pEList!=0 );
+      assert( pEList->nExpr>0 );
+      assert( sqlite3KeyInfoIsWriteable(pKeyInfo) );
+      for(i=0; i<nVal; i++){
+        Expr *p = sqlite3VectorFieldSubexpr(pLeft, i);
+        pKeyInfo->aColl[i] = sqlite3BinaryCompareCollSeq(
+            pParse, p, pEList->a[i].pExpr
+        );
+      }
+    }
+  }else if( ALWAYS(pExpr->x.pList!=0) ){
+    /* Case 2:     expr IN (exprlist)
+    **
+    ** For each expression, build an index key from the evaluation and
+    ** store it in the temporary table. If <expr> is a column, then use
+    ** that columns affinity when building index keys. If <expr> is not
+    ** a column, use numeric affinity.
+    */
+    char affinity;            /* Affinity of the LHS of the IN */
+    int i;
+    ExprList *pList = pExpr->x.pList;
+    struct ExprList_item *pItem;
+    int r1, r2;
+    affinity = sqlite3ExprAffinity(pLeft);
+    if( affinity<=SQLITE_AFF_NONE ){
+      affinity = SQLITE_AFF_BLOB;
+    }else if( affinity==SQLITE_AFF_REAL ){
+      affinity = SQLITE_AFF_NUMERIC;
+    }
+    if( pKeyInfo ){
+      assert( sqlite3KeyInfoIsWriteable(pKeyInfo) );
+      pKeyInfo->aColl[0] = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+    }
+
+    /* Loop through each expression in <exprlist>. */
+    r1 = sqlite3GetTempReg(pParse);
+    r2 = sqlite3GetTempReg(pParse);
+    for(i=pList->nExpr, pItem=pList->a; i>0; i--, pItem++){
+      Expr *pE2 = pItem->pExpr;
+
+      /* If the expression is not constant then we will need to
+      ** disable the test that was generated above that makes sure
+      ** this code only executes once.  Because for a non-constant
+      ** expression we need to rerun this code each time.
+      */
+      if( addrOnce && !sqlite3ExprIsConstant(pParse, pE2) ){
+        sqlite3VdbeChangeToNoop(v, addrOnce-1);
+        sqlite3VdbeChangeToNoop(v, addrOnce);
+        ExprClearProperty(pExpr, EP_Subrtn);
+        addrOnce = 0;
+      }
+
+      /* Evaluate the expression and insert it into the temp table */
+      sqlite3ExprCode(pParse, pE2, r1);
+      sqlite3VdbeAddOp4(v, OP_MakeRecord, r1, 1, r2, &affinity, 1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iTab, r2, r1, 1);
+    }
+    sqlite3ReleaseTempReg(pParse, r1);
+    sqlite3ReleaseTempReg(pParse, r2);
+  }
+  if( pSig ) pSig->bComplete = 1;
+  if( pKeyInfo ){
+    sqlite3VdbeChangeP4(v, addr, (void *)pKeyInfo, P4_KEYINFO);
+  }
+  if( addrOnce ){
+    sqlite3VdbeAddOp1(v, OP_NullRow, iTab);
+    sqlite3VdbeJumpHere(v, addrOnce);
+    /* Subroutine return */
+    assert( ExprUseYSub(pExpr) );
+    assert( sqlite3VdbeGetOp(v,pExpr->y.sub.iAddr-1)->opcode==OP_BeginSubrtn
+            || pParse->nErr );
+    sqlite3VdbeAddOp3(v, OP_Return, pExpr->y.sub.regReturn,
+                      pExpr->y.sub.iAddr, 1);
+    VdbeCoverage(v);
+    sqlite3ClearTempRegCache(pParse);
+  }
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+/*
+** Generate code for scalar subqueries used as a subquery expression
+** or EXISTS operator:
+**
+**     (SELECT a FROM b)          -- subquery
+**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
+**
+** The pExpr parameter is the SELECT or EXISTS operator to be coded.
+**
+** Return the register that holds the result.  For a multi-column SELECT,
+** the result is stored in a contiguous array of registers and the
+** return value is the register of the left-most result column.
+** Return 0 if an error occurs.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+SQLITE_PRIVATE int sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
+  int addrOnce = 0;           /* Address of OP_Once at top of subroutine */
+  int rReg = 0;               /* Register storing resulting */
+  Select *pSel;               /* SELECT statement to encode */
+  SelectDest dest;            /* How to deal with SELECT result */
+  int nReg;                   /* Registers to allocate */
+  Expr *pLimit;               /* New limit expression */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrExplain;            /* Address of OP_Explain instruction */
+#endif
+
+  Vdbe *v = pParse->pVdbe;
+  assert( v!=0 );
+  if( pParse->nErr ) return 0;
+  testcase( pExpr->op==TK_EXISTS );
+  testcase( pExpr->op==TK_SELECT );
+  assert( pExpr->op==TK_EXISTS || pExpr->op==TK_SELECT );
+  assert( ExprUseXSelect(pExpr) );
+  pSel = pExpr->x.pSelect;
+
+  /* If this routine has already been coded, then invoke it as a
+  ** subroutine. */
+  if( ExprHasProperty(pExpr, EP_Subrtn) ){
+    ExplainQueryPlan((pParse, 0, "REUSE SUBQUERY %d", pSel->selId));
+    assert( ExprUseYSub(pExpr) );
+    sqlite3VdbeAddOp2(v, OP_Gosub, pExpr->y.sub.regReturn,
+                      pExpr->y.sub.iAddr);
+    return pExpr->iTable;
+  }
+
+  /* Begin coding the subroutine */
+  assert( !ExprUseYWin(pExpr) );
+  assert( !ExprHasProperty(pExpr, EP_Reduced|EP_TokenOnly) );
+  ExprSetProperty(pExpr, EP_Subrtn);
+  pExpr->y.sub.regReturn = ++pParse->nMem;
+  pExpr->y.sub.iAddr =
+    sqlite3VdbeAddOp2(v, OP_BeginSubrtn, 0, pExpr->y.sub.regReturn) + 1;
+
+  /* The evaluation of the EXISTS/SELECT must be repeated every time it
+  ** is encountered if any of the following is true:
+  **
+  **    *  The right-hand side is a correlated subquery
+  **    *  The right-hand side is an expression list containing variables
+  **    *  We are inside a trigger
+  **
+  ** If all of the above are false, then we can run this code just once
+  ** save the results, and reuse the same result on subsequent invocations.
+  */
+  if( !ExprHasProperty(pExpr, EP_VarSelect) ){
+    addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+  }
+
+  /* For a SELECT, generate code to put the values for all columns of
+  ** the first row into an array of registers and return the index of
+  ** the first register.
+  **
+  ** If this is an EXISTS, write an integer 0 (not exists) or 1 (exists)
+  ** into a register and return that register number.
+  **
+  ** In both cases, the query is augmented with "LIMIT 1".  Any
+  ** preexisting limit is discarded in place of the new LIMIT 1.
+  */
+  ExplainQueryPlan2(addrExplain, (pParse, 1, "%sSCALAR SUBQUERY %d",
+        addrOnce?"":"CORRELATED ", pSel->selId));
+  sqlite3VdbeScanStatusCounters(v, addrExplain, addrExplain, -1);
+  nReg = pExpr->op==TK_SELECT ? pSel->pEList->nExpr : 1;
+  sqlite3SelectDestInit(&dest, 0, pParse->nMem+1);
+  pParse->nMem += nReg;
+  if( pExpr->op==TK_SELECT ){
+    dest.eDest = SRT_Mem;
+    dest.iSdst = dest.iSDParm;
+    dest.nSdst = nReg;
+    sqlite3VdbeAddOp3(v, OP_Null, 0, dest.iSDParm, dest.iSDParm+nReg-1);
+    VdbeComment((v, "Init subquery result"));
+  }else{
+    dest.eDest = SRT_Exists;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iSDParm);
+    VdbeComment((v, "Init EXISTS result"));
+  }
+  if( pSel->pLimit ){
+    /* The subquery already has a limit.  If the pre-existing limit is X
+    ** then make the new limit X<>0 so that the new limit is either 1 or 0 */
+    sqlite3 *db = pParse->db;
+    pLimit = sqlite3Expr(db, TK_INTEGER, "0");
+    if( pLimit ){
+      pLimit->affExpr = SQLITE_AFF_NUMERIC;
+      pLimit = sqlite3PExpr(pParse, TK_NE,
+                            sqlite3ExprDup(db, pSel->pLimit->pLeft, 0), pLimit);
+    }
+    sqlite3ExprDeferredDelete(pParse, pSel->pLimit->pLeft);
+    pSel->pLimit->pLeft = pLimit;
+  }else{
+    /* If there is no pre-existing limit add a limit of 1 */
+    pLimit = sqlite3Expr(pParse->db, TK_INTEGER, "1");
+    pSel->pLimit = sqlite3PExpr(pParse, TK_LIMIT, pLimit, 0);
+  }
+  pSel->iLimit = 0;
+  if( sqlite3Select(pParse, pSel, &dest) ){
+    pExpr->op2 = pExpr->op;
+    pExpr->op = TK_ERROR;
+    return 0;
+  }
+  pExpr->iTable = rReg = dest.iSDParm;
+  ExprSetVVAProperty(pExpr, EP_NoReduce);
+  if( addrOnce ){
+    sqlite3VdbeJumpHere(v, addrOnce);
+  }
+  sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1);
+
+  /* Subroutine return */
+  assert( ExprUseYSub(pExpr) );
+  assert( sqlite3VdbeGetOp(v,pExpr->y.sub.iAddr-1)->opcode==OP_BeginSubrtn
+          || pParse->nErr );
+  sqlite3VdbeAddOp3(v, OP_Return, pExpr->y.sub.regReturn,
+                    pExpr->y.sub.iAddr, 1);
+  VdbeCoverage(v);
+  sqlite3ClearTempRegCache(pParse);
+  return rReg;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Expr pIn is an IN(...) expression. This function checks that the
+** sub-select on the RHS of the IN() operator has the same number of
+** columns as the vector on the LHS. Or, if the RHS of the IN() is not
+** a sub-query, that the LHS is a vector of size 1.
+*/
+SQLITE_PRIVATE int sqlite3ExprCheckIN(Parse *pParse, Expr *pIn){
+  int nVector = sqlite3ExprVectorSize(pIn->pLeft);
+  if( ExprUseXSelect(pIn) && !pParse->db->mallocFailed ){
+    if( nVector!=pIn->x.pSelect->pEList->nExpr ){
+      sqlite3SubselectError(pParse, pIn->x.pSelect->pEList->nExpr, nVector);
+      return 1;
+    }
+  }else if( nVector!=1 ){
+    sqlite3VectorErrorMsg(pParse, pIn->pLeft);
+    return 1;
+  }
+  return 0;
+}
+#endif
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code for an IN expression.
+**
+**      x IN (SELECT ...)
+**      x IN (value, value, ...)
+**
+** The left-hand side (LHS) is a scalar or vector expression.  The
+** right-hand side (RHS) is an array of zero or more scalar values, or a
+** subquery.  If the RHS is a subquery, the number of result columns must
+** match the number of columns in the vector on the LHS.  If the RHS is
+** a list of values, the LHS must be a scalar.
+**
+** The IN operator is true if the LHS value is contained within the RHS.
+** The result is false if the LHS is definitely not in the RHS.  The
+** result is NULL if the presence of the LHS in the RHS cannot be
+** determined due to NULLs.
+**
+** This routine generates code that jumps to destIfFalse if the LHS is not
+** contained within the RHS.  If due to NULLs we cannot determine if the LHS
+** is contained in the RHS then jump to destIfNull.  If the LHS is contained
+** within the RHS then fall through.
+**
+** See the separate in-operator.md documentation file in the canonical
+** SQLite source tree for additional information.
+*/
+static void sqlite3ExprCodeIN(
+  Parse *pParse,        /* Parsing and code generating context */
+  Expr *pExpr,          /* The IN expression */
+  int destIfFalse,      /* Jump here if LHS is not contained in the RHS */
+  int destIfNull        /* Jump here if the results are unknown due to NULLs */
+){
+  int rRhsHasNull = 0;  /* Register that is true if RHS contains NULL values */
+  int eType;            /* Type of the RHS */
+  int rLhs;             /* Register(s) holding the LHS values */
+  int rLhsOrig;         /* LHS values prior to reordering by aiMap[] */
+  Vdbe *v;              /* Statement under construction */
+  int *aiMap = 0;       /* Map from vector field to index column */
+  char *zAff = 0;       /* Affinity string for comparisons */
+  int nVector;          /* Size of vectors for this IN operator */
+  int iDummy;           /* Dummy parameter to exprCodeVector() */
+  Expr *pLeft;          /* The LHS of the IN operator */
+  int i;                /* loop counter */
+  int destStep2;        /* Where to jump when NULLs seen in step 2 */
+  int destStep6 = 0;    /* Start of code for Step 6 */
+  int addrTruthOp;      /* Address of opcode that determines the IN is true */
+  int destNotNull;      /* Jump here if a comparison is not true in step 6 */
+  int addrTop;          /* Top of the step-6 loop */
+  int iTab = 0;         /* Index to use */
+  u8 okConstFactor = pParse->okConstFactor;
+
+  assert( !ExprHasVVAProperty(pExpr,EP_Immutable) );
+  pLeft = pExpr->pLeft;
+  if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
+  zAff = exprINAffinity(pParse, pExpr);
+  nVector = sqlite3ExprVectorSize(pExpr->pLeft);
+  aiMap = (int*)sqlite3DbMallocZero(pParse->db, nVector*sizeof(int));
+  if( pParse->db->mallocFailed ) goto sqlite3ExprCodeIN_oom_error;
+
+  /* Attempt to compute the RHS. After this step, if anything other than
+  ** IN_INDEX_NOOP is returned, the table opened with cursor iTab
+  ** contains the values that make up the RHS. If IN_INDEX_NOOP is returned,
+  ** the RHS has not yet been coded.  */
+  v = pParse->pVdbe;
+  assert( v!=0 );       /* OOM detected prior to this routine */
+  VdbeNoopComment((v, "begin IN expr"));
+  eType = sqlite3FindInIndex(pParse, pExpr,
+                             IN_INDEX_MEMBERSHIP | IN_INDEX_NOOP_OK,
+                             destIfFalse==destIfNull ? 0 : &rRhsHasNull,
+                             aiMap, &iTab);
+
+  assert( pParse->nErr || nVector==1 || eType==IN_INDEX_EPH
+       || eType==IN_INDEX_INDEX_ASC || eType==IN_INDEX_INDEX_DESC
+  );
+#ifdef SQLITE_DEBUG
+  /* Confirm that aiMap[] contains nVector integer values between 0 and
+  ** nVector-1. */
+  for(i=0; i<nVector; i++){
+    int j, cnt;
+    for(cnt=j=0; j<nVector; j++) if( aiMap[j]==i ) cnt++;
+    assert( cnt==1 );
+  }
+#endif
+
+  /* Code the LHS, the <expr> from "<expr> IN (...)". If the LHS is a
+  ** vector, then it is stored in an array of nVector registers starting
+  ** at r1.
+  **
+  ** sqlite3FindInIndex() might have reordered the fields of the LHS vector
+  ** so that the fields are in the same order as an existing index.   The
+  ** aiMap[] array contains a mapping from the original LHS field order to
+  ** the field order that matches the RHS index.
+  **
+  ** Avoid factoring the LHS of the IN(...) expression out of the loop,
+  ** even if it is constant, as OP_Affinity may be used on the register
+  ** by code generated below.  */
+  assert( pParse->okConstFactor==okConstFactor );
+  pParse->okConstFactor = 0;
+  rLhsOrig = exprCodeVector(pParse, pLeft, &iDummy);
+  pParse->okConstFactor = okConstFactor;
+  for(i=0; i<nVector && aiMap[i]==i; i++){} /* Are LHS fields reordered? */
+  if( i==nVector ){
+    /* LHS fields are not reordered */
+    rLhs = rLhsOrig;
+  }else{
+    /* Need to reorder the LHS fields according to aiMap */
+    rLhs = sqlite3GetTempRange(pParse, nVector);
+    for(i=0; i<nVector; i++){
+      sqlite3VdbeAddOp3(v, OP_Copy, rLhsOrig+i, rLhs+aiMap[i], 0);
+    }
+  }
+
+  /* If sqlite3FindInIndex() did not find or create an index that is
+  ** suitable for evaluating the IN operator, then evaluate using a
+  ** sequence of comparisons.
+  **
+  ** This is step (1) in the in-operator.md optimized algorithm.
+  */
+  if( eType==IN_INDEX_NOOP ){
+    ExprList *pList;
+    CollSeq *pColl;
+    int labelOk = sqlite3VdbeMakeLabel(pParse);
+    int r2, regToFree;
+    int regCkNull = 0;
+    int ii;
+    assert( ExprUseXList(pExpr) );
+    pList = pExpr->x.pList;
+    pColl = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+    if( destIfNull!=destIfFalse ){
+      regCkNull = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_BitAnd, rLhs, rLhs, regCkNull);
+    }
+    for(ii=0; ii<pList->nExpr; ii++){
+      r2 = sqlite3ExprCodeTemp(pParse, pList->a[ii].pExpr, ®ToFree);
+      if( regCkNull && sqlite3ExprCanBeNull(pList->a[ii].pExpr) ){
+        sqlite3VdbeAddOp3(v, OP_BitAnd, regCkNull, r2, regCkNull);
+      }
+      sqlite3ReleaseTempReg(pParse, regToFree);
+      if( ii<pList->nExpr-1 || destIfNull!=destIfFalse ){
+        int op = rLhs!=r2 ? OP_Eq : OP_NotNull;
+        sqlite3VdbeAddOp4(v, op, rLhs, labelOk, r2,
+                          (void*)pColl, P4_COLLSEQ);
+        VdbeCoverageIf(v, ii<pList->nExpr-1 && op==OP_Eq);
+        VdbeCoverageIf(v, ii==pList->nExpr-1 && op==OP_Eq);
+        VdbeCoverageIf(v, ii<pList->nExpr-1 && op==OP_NotNull);
+        VdbeCoverageIf(v, ii==pList->nExpr-1 && op==OP_NotNull);
+        sqlite3VdbeChangeP5(v, zAff[0]);
+      }else{
+        int op = rLhs!=r2 ? OP_Ne : OP_IsNull;
+        assert( destIfNull==destIfFalse );
+        sqlite3VdbeAddOp4(v, op, rLhs, destIfFalse, r2,
+                          (void*)pColl, P4_COLLSEQ);
+        VdbeCoverageIf(v, op==OP_Ne);
+        VdbeCoverageIf(v, op==OP_IsNull);
+        sqlite3VdbeChangeP5(v, zAff[0] | SQLITE_JUMPIFNULL);
+      }
+    }
+    if( regCkNull ){
+      sqlite3VdbeAddOp2(v, OP_IsNull, regCkNull, destIfNull); VdbeCoverage(v);
+      sqlite3VdbeGoto(v, destIfFalse);
+    }
+    sqlite3VdbeResolveLabel(v, labelOk);
+    sqlite3ReleaseTempReg(pParse, regCkNull);
+    goto sqlite3ExprCodeIN_finished;
+  }
+
+  /* Step 2: Check to see if the LHS contains any NULL columns.  If the
+  ** LHS does contain NULLs then the result must be either FALSE or NULL.
+  ** We will then skip the binary search of the RHS.
+  */
+  if( destIfNull==destIfFalse ){
+    destStep2 = destIfFalse;
+  }else{
+    destStep2 = destStep6 = sqlite3VdbeMakeLabel(pParse);
+  }
+  for(i=0; i<nVector; i++){
+    Expr *p = sqlite3VectorFieldSubexpr(pExpr->pLeft, i);
+    if( pParse->nErr ) goto sqlite3ExprCodeIN_oom_error;
+    if( sqlite3ExprCanBeNull(p) ){
+      sqlite3VdbeAddOp2(v, OP_IsNull, rLhs+i, destStep2);
+      VdbeCoverage(v);
+    }
+  }
+
+  /* Step 3.  The LHS is now known to be non-NULL.  Do the binary search
+  ** of the RHS using the LHS as a probe.  If found, the result is
+  ** true.
+  */
+  if( eType==IN_INDEX_ROWID ){
+    /* In this case, the RHS is the ROWID of table b-tree and so we also
+    ** know that the RHS is non-NULL.  Hence, we combine steps 3 and 4
+    ** into a single opcode. */
+    sqlite3VdbeAddOp3(v, OP_SeekRowid, iTab, destIfFalse, rLhs);
+    VdbeCoverage(v);
+    addrTruthOp = sqlite3VdbeAddOp0(v, OP_Goto);  /* Return True */
+  }else{
+    sqlite3VdbeAddOp4(v, OP_Affinity, rLhs, nVector, 0, zAff, nVector);
+    if( destIfFalse==destIfNull ){
+      /* Combine Step 3 and Step 5 into a single opcode */
+      if( ExprHasProperty(pExpr, EP_Subrtn) ){
+        const VdbeOp *pOp = sqlite3VdbeGetOp(v, pExpr->y.sub.iAddr);
+        assert( pOp->opcode==OP_Once || pParse->nErr );
+        if( pOp->opcode==OP_Once && pOp->p3>0 ){
+          assert( OptimizationEnabled(pParse->db, SQLITE_BloomFilter) );
+          sqlite3VdbeAddOp4Int(v, OP_Filter, pOp->p3, destIfFalse,
+                               rLhs, nVector); VdbeCoverage(v);
+        }
+      }
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, iTab, destIfFalse,
+                           rLhs, nVector); VdbeCoverage(v);
+      goto sqlite3ExprCodeIN_finished;
+    }
+    /* Ordinary Step 3, for the case where FALSE and NULL are distinct */
+    addrTruthOp = sqlite3VdbeAddOp4Int(v, OP_Found, iTab, 0,
+                                      rLhs, nVector); VdbeCoverage(v);
+  }
+
+  /* Step 4.  If the RHS is known to be non-NULL and we did not find
+  ** an match on the search above, then the result must be FALSE.
+  */
+  if( rRhsHasNull && nVector==1 ){
+    sqlite3VdbeAddOp2(v, OP_NotNull, rRhsHasNull, destIfFalse);
+    VdbeCoverage(v);
+  }
+
+  /* Step 5.  If we do not care about the difference between NULL and
+  ** FALSE, then just return false.
+  */
+  if( destIfFalse==destIfNull ) sqlite3VdbeGoto(v, destIfFalse);
+
+  /* Step 6: Loop through rows of the RHS.  Compare each row to the LHS.
+  ** If any comparison is NULL, then the result is NULL.  If all
+  ** comparisons are FALSE then the final result is FALSE.
+  **
+  ** For a scalar LHS, it is sufficient to check just the first row
+  ** of the RHS.
+  */
+  if( destStep6 ) sqlite3VdbeResolveLabel(v, destStep6);
+  addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, destIfFalse);
+  VdbeCoverage(v);
+  if( nVector>1 ){
+    destNotNull = sqlite3VdbeMakeLabel(pParse);
+  }else{
+    /* For nVector==1, combine steps 6 and 7 by immediately returning
+    ** FALSE if the first comparison is not NULL */
+    destNotNull = destIfFalse;
+  }
+  for(i=0; i<nVector; i++){
+    Expr *p;
+    CollSeq *pColl;
+    int r3 = sqlite3GetTempReg(pParse);
+    p = sqlite3VectorFieldSubexpr(pLeft, i);
+    pColl = sqlite3ExprCollSeq(pParse, p);
+    sqlite3VdbeAddOp3(v, OP_Column, iTab, i, r3);
+    sqlite3VdbeAddOp4(v, OP_Ne, rLhs+i, destNotNull, r3,
+                      (void*)pColl, P4_COLLSEQ);
+    VdbeCoverage(v);
+    sqlite3ReleaseTempReg(pParse, r3);
+  }
+  sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfNull);
+  if( nVector>1 ){
+    sqlite3VdbeResolveLabel(v, destNotNull);
+    sqlite3VdbeAddOp2(v, OP_Next, iTab, addrTop+1);
+    VdbeCoverage(v);
+
+    /* Step 7:  If we reach this point, we know that the result must
+    ** be false. */
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse);
+  }
+
+  /* Jumps here in order to return true. */
+  sqlite3VdbeJumpHere(v, addrTruthOp);
+
+sqlite3ExprCodeIN_finished:
+  if( rLhs!=rLhsOrig ) sqlite3ReleaseTempReg(pParse, rLhs);
+  VdbeComment((v, "end IN expr"));
+sqlite3ExprCodeIN_oom_error:
+  sqlite3DbFree(pParse->db, aiMap);
+  sqlite3DbFree(pParse->db, zAff);
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Generate an instruction that will put the floating point
+** value described by z[0..n-1] into register iMem.
+**
+** The z[] string will probably not be zero-terminated.  But the
+** z[n] character is guaranteed to be something that does not look
+** like the continuation of the number.
+*/
+static void codeReal(Vdbe *v, const char *z, int negateFlag, int iMem){
+  if( ALWAYS(z!=0) ){
+    double value;
+    sqlite3AtoF(z, &value, sqlite3Strlen30(z), SQLITE_UTF8);
+    assert( !sqlite3IsNaN(value) ); /* The new AtoF never returns NaN */
+    if( negateFlag ) value = -value;
+    sqlite3VdbeAddOp4Dup8(v, OP_Real, 0, iMem, 0, (u8*)&value, P4_REAL);
+  }
+}
+#endif
+
+
+/*
+** Generate an instruction that will put the integer describe by
+** text z[0..n-1] into register iMem.
+**
+** Expr.u.zToken is always UTF8 and zero-terminated.
+*/
+static void codeInteger(Parse *pParse, Expr *pExpr, int negFlag, int iMem){
+  Vdbe *v = pParse->pVdbe;
+  if( pExpr->flags & EP_IntValue ){
+    int i = pExpr->u.iValue;
+    assert( i>=0 );
+    if( negFlag ) i = -i;
+    sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
+  }else{
+    int c;
+    i64 value;
+    const char *z = pExpr->u.zToken;
+    assert( z!=0 );
+    c = sqlite3DecOrHexToI64(z, &value);
+    if( (c==3 && !negFlag) || (c==2) || (negFlag && value==SMALLEST_INT64)){
+#ifdef SQLITE_OMIT_FLOATING_POINT
+      sqlite3ErrorMsg(pParse, "oversized integer: %s%#T", negFlag?"-":"",pExpr);
+#else
+#ifndef SQLITE_OMIT_HEX_INTEGER
+      if( sqlite3_strnicmp(z,"0x",2)==0 ){
+        sqlite3ErrorMsg(pParse, "hex literal too big: %s%#T",
+                        negFlag?"-":"",pExpr);
+      }else
+#endif
+      {
+        codeReal(v, z, negFlag, iMem);
+      }
+#endif
+    }else{
+      if( negFlag ){ value = c==3 ? SMALLEST_INT64 : -value; }
+      sqlite3VdbeAddOp4Dup8(v, OP_Int64, 0, iMem, 0, (u8*)&value, P4_INT64);
+    }
+  }
+}
+
+
+/* Generate code that will load into register regOut a value that is
+** appropriate for the iIdxCol-th column of index pIdx.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeLoadIndexColumn(
+  Parse *pParse,  /* The parsing context */
+  Index *pIdx,    /* The index whose column is to be loaded */
+  int iTabCur,    /* Cursor pointing to a table row */
+  int iIdxCol,    /* The column of the index to be loaded */
+  int regOut      /* Store the index column value in this register */
+){
+  i16 iTabCol = pIdx->aiColumn[iIdxCol];
+  if( iTabCol==XN_EXPR ){
+    assert( pIdx->aColExpr );
+    assert( pIdx->aColExpr->nExpr>iIdxCol );
+    pParse->iSelfTab = iTabCur + 1;
+    sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[iIdxCol].pExpr, regOut);
+    pParse->iSelfTab = 0;
+  }else{
+    sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pIdx->pTable, iTabCur,
+                                    iTabCol, regOut);
+  }
+}
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+/*
+** Generate code that will compute the value of generated column pCol
+** and store the result in register regOut
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeGeneratedColumn(
+  Parse *pParse,     /* Parsing context */
+  Table *pTab,       /* Table containing the generated column */
+  Column *pCol,      /* The generated column */
+  int regOut         /* Put the result in this register */
+){
+  int iAddr;
+  Vdbe *v = pParse->pVdbe;
+  int nErr = pParse->nErr;
+  assert( v!=0 );
+  assert( pParse->iSelfTab!=0 );
+  if( pParse->iSelfTab>0 ){
+    iAddr = sqlite3VdbeAddOp3(v, OP_IfNullRow, pParse->iSelfTab-1, 0, regOut);
+  }else{
+    iAddr = 0;
+  }
+  sqlite3ExprCodeCopy(pParse, sqlite3ColumnExpr(pTab,pCol), regOut);
+  if( pCol->affinity>=SQLITE_AFF_TEXT ){
+    sqlite3VdbeAddOp4(v, OP_Affinity, regOut, 1, 0, &pCol->affinity, 1);
+  }
+  if( iAddr ) sqlite3VdbeJumpHere(v, iAddr);
+  if( pParse->nErr>nErr ) pParse->db->errByteOffset = -1;
+}
+#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
+
+/*
+** Generate code to extract the value of the iCol-th column of a table.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeGetColumnOfTable(
+  Vdbe *v,        /* Parsing context */
+  Table *pTab,    /* The table containing the value */
+  int iTabCur,    /* The table cursor.  Or the PK cursor for WITHOUT ROWID */
+  int iCol,       /* Index of the column to extract */
+  int regOut      /* Extract the value into this register */
+){
+  Column *pCol;
+  assert( v!=0 );
+  assert( pTab!=0 );
+  assert( iCol!=XN_EXPR );
+  if( iCol<0 || iCol==pTab->iPKey ){
+    sqlite3VdbeAddOp2(v, OP_Rowid, iTabCur, regOut);
+    VdbeComment((v, "%s.rowid", pTab->zName));
+  }else{
+    int op;
+    int x;
+    if( IsVirtual(pTab) ){
+      op = OP_VColumn;
+      x = iCol;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    }else if( (pCol = &pTab->aCol[iCol])->colFlags & COLFLAG_VIRTUAL ){
+      Parse *pParse = sqlite3VdbeParser(v);
+      if( pCol->colFlags & COLFLAG_BUSY ){
+        sqlite3ErrorMsg(pParse, "generated column loop on \"%s\"",
+                        pCol->zCnName);
+      }else{
+        int savedSelfTab = pParse->iSelfTab;
+        pCol->colFlags |= COLFLAG_BUSY;
+        pParse->iSelfTab = iTabCur+1;
+        sqlite3ExprCodeGeneratedColumn(pParse, pTab, pCol, regOut);
+        pParse->iSelfTab = savedSelfTab;
+        pCol->colFlags &= ~COLFLAG_BUSY;
+      }
+      return;
+#endif
+    }else if( !HasRowid(pTab) ){
+      testcase( iCol!=sqlite3TableColumnToStorage(pTab, iCol) );
+      x = sqlite3TableColumnToIndex(sqlite3PrimaryKeyIndex(pTab), iCol);
+      op = OP_Column;
+    }else{
+      x = sqlite3TableColumnToStorage(pTab,iCol);
+      testcase( x!=iCol );
+      op = OP_Column;
+    }
+    sqlite3VdbeAddOp3(v, op, iTabCur, x, regOut);
+    sqlite3ColumnDefault(v, pTab, iCol, regOut);
+  }
+}
+
+/*
+** Generate code that will extract the iColumn-th column from
+** table pTab and store the column value in register iReg.
+**
+** There must be an open cursor to pTab in iTable when this routine
+** is called.  If iColumn<0 then code is generated that extracts the rowid.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(
+  Parse *pParse,   /* Parsing and code generating context */
+  Table *pTab,     /* Description of the table we are reading from */
+  int iColumn,     /* Index of the table column */
+  int iTable,      /* The cursor pointing to the table */
+  int iReg,        /* Store results here */
+  u8 p5            /* P5 value for OP_Column + FLAGS */
+){
+  assert( pParse->pVdbe!=0 );
+  assert( (p5 & (OPFLAG_NOCHNG|OPFLAG_TYPEOFARG|OPFLAG_LENGTHARG))==p5 );
+  assert( IsVirtual(pTab) || (p5 & OPFLAG_NOCHNG)==0 );
+  sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pTab, iTable, iColumn, iReg);
+  if( p5 ){
+    VdbeOp *pOp = sqlite3VdbeGetLastOp(pParse->pVdbe);
+    if( pOp->opcode==OP_Column ) pOp->p5 = p5;
+    if( pOp->opcode==OP_VColumn ) pOp->p5 = (p5 & OPFLAG_NOCHNG);
+  }
+  return iReg;
+}
+
+/*
+** Generate code to move content from registers iFrom...iFrom+nReg-1
+** over to iTo..iTo+nReg-1.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
+  sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);
+}
+
+/*
+** Convert a scalar expression node to a TK_REGISTER referencing
+** register iReg.  The caller must ensure that iReg already contains
+** the correct value for the expression.
+*/
+SQLITE_PRIVATE void sqlite3ExprToRegister(Expr *pExpr, int iReg){
+  Expr *p = sqlite3ExprSkipCollateAndLikely(pExpr);
+  if( NEVER(p==0) ) return;
+  if( p->op==TK_REGISTER ){
+    assert( p->iTable==iReg );
+  }else{
+    p->op2 = p->op;
+    p->op = TK_REGISTER;
+    p->iTable = iReg;
+    ExprClearProperty(p, EP_Skip);
+  }
+}
+
+/*
+** Evaluate an expression (either a vector or a scalar expression) and store
+** the result in contiguous temporary registers.  Return the index of
+** the first register used to store the result.
+**
+** If the returned result register is a temporary scalar, then also write
+** that register number into *piFreeable.  If the returned result register
+** is not a temporary or if the expression is a vector set *piFreeable
+** to 0.
+*/
+static int exprCodeVector(Parse *pParse, Expr *p, int *piFreeable){
+  int iResult;
+  int nResult = sqlite3ExprVectorSize(p);
+  if( nResult==1 ){
+    iResult = sqlite3ExprCodeTemp(pParse, p, piFreeable);
+  }else{
+    *piFreeable = 0;
+    if( p->op==TK_SELECT ){
+#if SQLITE_OMIT_SUBQUERY
+      iResult = 0;
+#else
+      iResult = sqlite3CodeSubselect(pParse, p);
+#endif
+    }else{
+      int i;
+      iResult = pParse->nMem+1;
+      pParse->nMem += nResult;
+      assert( ExprUseXList(p) );
+      for(i=0; i<nResult; i++){
+        sqlite3ExprCodeFactorable(pParse, p->x.pList->a[i].pExpr, i+iResult);
+      }
+    }
+  }
+  return iResult;
+}
+
+/*
+** If the last opcode is a OP_Copy, then set the do-not-merge flag (p5)
+** so that a subsequent copy will not be merged into this one.
+*/
+static void setDoNotMergeFlagOnCopy(Vdbe *v){
+  if( sqlite3VdbeGetLastOp(v)->opcode==OP_Copy ){
+    sqlite3VdbeChangeP5(v, 1);  /* Tag trailing OP_Copy as not mergeable */
+  }
+}
+
+/*
+** Generate code to implement special SQL functions that are implemented
+** in-line rather than by using the usual callbacks.
+*/
+static int exprCodeInlineFunction(
+  Parse *pParse,        /* Parsing context */
+  ExprList *pFarg,      /* List of function arguments */
+  int iFuncId,          /* Function ID.  One of the INTFUNC_... values */
+  int target            /* Store function result in this register */
+){
+  int nFarg;
+  Vdbe *v = pParse->pVdbe;
+  assert( v!=0 );
+  assert( pFarg!=0 );
+  nFarg = pFarg->nExpr;
+  assert( nFarg>0 );  /* All in-line functions have at least one argument */
+  switch( iFuncId ){
+    case INLINEFUNC_coalesce: {
+      /* Attempt a direct implementation of the built-in COALESCE() and
+      ** IFNULL() functions.  This avoids unnecessary evaluation of
+      ** arguments past the first non-NULL argument.
+      */
+      int endCoalesce = sqlite3VdbeMakeLabel(pParse);
+      int i;
+      assert( nFarg>=2 );
+      sqlite3ExprCode(pParse, pFarg->a[0].pExpr, target);
+      for(i=1; i<nFarg; i++){
+        sqlite3VdbeAddOp2(v, OP_NotNull, target, endCoalesce);
+        VdbeCoverage(v);
+        sqlite3ExprCode(pParse, pFarg->a[i].pExpr, target);
+      }
+      setDoNotMergeFlagOnCopy(v);
+      sqlite3VdbeResolveLabel(v, endCoalesce);
+      break;
+    }
+    case INLINEFUNC_iif: {
+      Expr caseExpr;
+      memset(&caseExpr, 0, sizeof(caseExpr));
+      caseExpr.op = TK_CASE;
+      caseExpr.x.pList = pFarg;
+      return sqlite3ExprCodeTarget(pParse, &caseExpr, target);
+    }
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+    case INLINEFUNC_sqlite_offset: {
+      Expr *pArg = pFarg->a[0].pExpr;
+      if( pArg->op==TK_COLUMN && pArg->iTable>=0 ){
+        sqlite3VdbeAddOp3(v, OP_Offset, pArg->iTable, pArg->iColumn, target);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      }
+      break;
+    }
+#endif
+    default: {
+      /* The UNLIKELY() function is a no-op.  The result is the value
+      ** of the first argument.
+      */
+      assert( nFarg==1 || nFarg==2 );
+      target = sqlite3ExprCodeTarget(pParse, pFarg->a[0].pExpr, target);
+      break;
+    }
+
+  /***********************************************************************
+  ** Test-only SQL functions that are only usable if enabled
+  ** via SQLITE_TESTCTRL_INTERNAL_FUNCTIONS
+  */
+#if !defined(SQLITE_UNTESTABLE)
+    case INLINEFUNC_expr_compare: {
+      /* Compare two expressions using sqlite3ExprCompare() */
+      assert( nFarg==2 );
+      sqlite3VdbeAddOp2(v, OP_Integer,
+         sqlite3ExprCompare(0,pFarg->a[0].pExpr, pFarg->a[1].pExpr,-1),
+         target);
+      break;
+    }
+
+    case INLINEFUNC_expr_implies_expr: {
+      /* Compare two expressions using sqlite3ExprImpliesExpr() */
+      assert( nFarg==2 );
+      sqlite3VdbeAddOp2(v, OP_Integer,
+         sqlite3ExprImpliesExpr(pParse,pFarg->a[0].pExpr, pFarg->a[1].pExpr,-1),
+         target);
+      break;
+    }
+
+    case INLINEFUNC_implies_nonnull_row: {
+      /* Result of sqlite3ExprImpliesNonNullRow() */
+      Expr *pA1;
+      assert( nFarg==2 );
+      pA1 = pFarg->a[1].pExpr;
+      if( pA1->op==TK_COLUMN ){
+        sqlite3VdbeAddOp2(v, OP_Integer,
+           sqlite3ExprImpliesNonNullRow(pFarg->a[0].pExpr,pA1->iTable,1),
+           target);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      }
+      break;
+    }
+
+    case INLINEFUNC_affinity: {
+      /* The AFFINITY() function evaluates to a string that describes
+      ** the type affinity of the argument.  This is used for testing of
+      ** the SQLite type logic.
+      */
+      const char *azAff[] = { "blob", "text", "numeric", "integer",
+                              "real", "flexnum" };
+      char aff;
+      assert( nFarg==1 );
+      aff = sqlite3ExprAffinity(pFarg->a[0].pExpr);
+      assert( aff<=SQLITE_AFF_NONE
+           || (aff>=SQLITE_AFF_BLOB && aff<=SQLITE_AFF_FLEXNUM) );
+      sqlite3VdbeLoadString(v, target,
+              (aff<=SQLITE_AFF_NONE) ? "none" : azAff[aff-SQLITE_AFF_BLOB]);
+      break;
+    }
+#endif /* !defined(SQLITE_UNTESTABLE) */
+  }
+  return target;
+}
+
+/*
+** Expression Node callback for sqlite3ExprCanReturnSubtype().
+**
+** Only a function call is able to return a subtype.  So if the node
+** is not a function call, return WRC_Prune immediately.
+**
+** A function call is able to return a subtype if it has the
+** SQLITE_RESULT_SUBTYPE property.
+**
+** Assume that every function is able to pass-through a subtype from
+** one of its argument (using sqlite3_result_value()).  Most functions
+** are not this way, but we don't have a mechanism to distinguish those
+** that are from those that are not, so assume they all work this way.
+** That means that if one of its arguments is another function and that
+** other function is able to return a subtype, then this function is
+** able to return a subtype.
+*/
+static int exprNodeCanReturnSubtype(Walker *pWalker, Expr *pExpr){
+  int n;
+  FuncDef *pDef;
+  sqlite3 *db;
+  if( pExpr->op!=TK_FUNCTION ){
+    return WRC_Prune;
+  }
+  assert( ExprUseXList(pExpr) );
+  db = pWalker->pParse->db;
+  n = ALWAYS(pExpr->x.pList) ? pExpr->x.pList->nExpr : 0;
+  pDef = sqlite3FindFunction(db, pExpr->u.zToken, n, ENC(db), 0);
+  if( NEVER(pDef==0) || (pDef->funcFlags & SQLITE_RESULT_SUBTYPE)!=0 ){
+    pWalker->eCode = 1;
+    return WRC_Prune;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Return TRUE if expression pExpr is able to return a subtype.
+**
+** A TRUE return does not guarantee that a subtype will be returned.
+** It only indicates that a subtype return is possible.  False positives
+** are acceptable as they only disable an optimization.  False negatives,
+** on the other hand, can lead to incorrect answers.
+*/
+static int sqlite3ExprCanReturnSubtype(Parse *pParse, Expr *pExpr){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.pParse = pParse;
+  w.xExprCallback = exprNodeCanReturnSubtype;
+  sqlite3WalkExpr(&w, pExpr);
+  return w.eCode;
+}
+
+
+/*
+** Check to see if pExpr is one of the indexed expressions on pParse->pIdxEpr.
+** If it is, then resolve the expression by reading from the index and
+** return the register into which the value has been read.  If pExpr is
+** not an indexed expression, then return negative.
+*/
+static SQLITE_NOINLINE int sqlite3IndexedExprLookup(
+  Parse *pParse,   /* The parsing context */
+  Expr *pExpr,     /* The expression to potentially bypass */
+  int target       /* Where to store the result of the expression */
+){
+  IndexedExpr *p;
+  Vdbe *v;
+  for(p=pParse->pIdxEpr; p; p=p->pIENext){
+    u8 exprAff;
+    int iDataCur = p->iDataCur;
+    if( iDataCur<0 ) continue;
+    if( pParse->iSelfTab ){
+      if( p->iDataCur!=pParse->iSelfTab-1 ) continue;
+      iDataCur = -1;
+    }
+    if( sqlite3ExprCompare(0, pExpr, p->pExpr, iDataCur)!=0 ) continue;
+    assert( p->aff>=SQLITE_AFF_BLOB && p->aff<=SQLITE_AFF_NUMERIC );
+    exprAff = sqlite3ExprAffinity(pExpr);
+    if( (exprAff<=SQLITE_AFF_BLOB && p->aff!=SQLITE_AFF_BLOB)
+     || (exprAff==SQLITE_AFF_TEXT && p->aff!=SQLITE_AFF_TEXT)
+     || (exprAff>=SQLITE_AFF_NUMERIC && p->aff!=SQLITE_AFF_NUMERIC)
+    ){
+      /* Affinity mismatch on a generated column */
+      continue;
+    }
+
+
+    /* Functions that might set a subtype should not be replaced by the
+    ** value taken from an expression index if they are themselves an
+    ** argument to another scalar function or aggregate.
+    ** https://sqlite.org/forum/forumpost/68d284c86b082c3e */
+    if( ExprHasProperty(pExpr, EP_SubtArg)
+     && sqlite3ExprCanReturnSubtype(pParse, pExpr)
+    ){
+      continue;
+    }
+
+    v = pParse->pVdbe;
+    assert( v!=0 );
+    if( p->bMaybeNullRow ){
+      /* If the index is on a NULL row due to an outer join, then we
+      ** cannot extract the value from the index.  The value must be
+      ** computed using the original expression. */
+      int addr = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp3(v, OP_IfNullRow, p->iIdxCur, addr+3, target);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_Column, p->iIdxCur, p->iIdxCol, target);
+      VdbeComment((v, "%s expr-column %d", p->zIdxName, p->iIdxCol));
+      sqlite3VdbeGoto(v, 0);
+      p = pParse->pIdxEpr;
+      pParse->pIdxEpr = 0;
+      sqlite3ExprCode(pParse, pExpr, target);
+      pParse->pIdxEpr = p;
+      sqlite3VdbeJumpHere(v, addr+2);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_Column, p->iIdxCur, p->iIdxCol, target);
+      VdbeComment((v, "%s expr-column %d", p->zIdxName, p->iIdxCol));
+    }
+    return target;
+  }
+  return -1;  /* Not found */
+}
+
+
+/*
+** Expresion pExpr is guaranteed to be a TK_COLUMN or equivalent. This
+** function checks the Parse.pIdxPartExpr list to see if this column
+** can be replaced with a constant value. If so, it generates code to
+** put the constant value in a register (ideally, but not necessarily,
+** register iTarget) and returns the register number.
+**
+** Or, if the TK_COLUMN cannot be replaced by a constant, zero is
+** returned.
+*/
+static int exprPartidxExprLookup(Parse *pParse, Expr *pExpr, int iTarget){
+  IndexedExpr *p;
+  for(p=pParse->pIdxPartExpr; p; p=p->pIENext){
+    if( pExpr->iColumn==p->iIdxCol && pExpr->iTable==p->iDataCur ){
+      Vdbe *v = pParse->pVdbe;
+      int addr = 0;
+      int ret;
+
+      if( p->bMaybeNullRow ){
+        addr = sqlite3VdbeAddOp1(v, OP_IfNullRow, p->iIdxCur);
+      }
+      ret = sqlite3ExprCodeTarget(pParse, p->pExpr, iTarget);
+      sqlite3VdbeAddOp4(pParse->pVdbe, OP_Affinity, ret, 1, 0,
+                        (const char*)&p->aff, 1);
+      if( addr ){
+        sqlite3VdbeJumpHere(v, addr);
+        sqlite3VdbeChangeP3(v, addr, ret);
+      }
+      return ret;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** Generate code into the current Vdbe to evaluate the given
+** expression.  Attempt to store the results in register "target".
+** Return the register where results are stored.
+**
+** With this routine, there is no guarantee that results will
+** be stored in target.  The result might be stored in some other
+** register if it is convenient to do so.  The calling function
+** must check the return code and move the results to the desired
+** register.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
+  Vdbe *v = pParse->pVdbe;  /* The VM under construction */
+  int op;                   /* The opcode being coded */
+  int inReg = target;       /* Results stored in register inReg */
+  int regFree1 = 0;         /* If non-zero free this temporary register */
+  int regFree2 = 0;         /* If non-zero free this temporary register */
+  int r1, r2;               /* Various register numbers */
+  Expr tempX;               /* Temporary expression node */
+  int p5 = 0;
+
+  assert( target>0 && target<=pParse->nMem );
+  assert( v!=0 );
+
+expr_code_doover:
+  if( pExpr==0 ){
+    op = TK_NULL;
+  }else if( pParse->pIdxEpr!=0
+   && !ExprHasProperty(pExpr, EP_Leaf)
+   && (r1 = sqlite3IndexedExprLookup(pParse, pExpr, target))>=0
+  ){
+    return r1;
+  }else{
+    assert( !ExprHasVVAProperty(pExpr,EP_Immutable) );
+    op = pExpr->op;
+  }
+  assert( op!=TK_ORDER );
+  switch( op ){
+    case TK_AGG_COLUMN: {
+      AggInfo *pAggInfo = pExpr->pAggInfo;
+      struct AggInfo_col *pCol;
+      assert( pAggInfo!=0 );
+      assert( pExpr->iAgg>=0 );
+      if( pExpr->iAgg>=pAggInfo->nColumn ){
+        /* Happens when the left table of a RIGHT JOIN is null and
+        ** is using an expression index */
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+#ifdef SQLITE_VDBE_COVERAGE
+        /* Verify that the OP_Null above is exercised by tests
+        ** tag-20230325-2 */
+        sqlite3VdbeAddOp3(v, OP_NotNull, target, 1, 20230325);
+        VdbeCoverageNeverTaken(v);
+#endif
+        break;
+      }
+      pCol = &pAggInfo->aCol[pExpr->iAgg];
+      if( !pAggInfo->directMode ){
+        return AggInfoColumnReg(pAggInfo, pExpr->iAgg);
+      }else if( pAggInfo->useSortingIdx ){
+        Table *pTab = pCol->pTab;
+        sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdxPTab,
+                              pCol->iSorterColumn, target);
+        if( pTab==0 ){
+          /* No comment added */
+        }else if( pCol->iColumn<0 ){
+          VdbeComment((v,"%s.rowid",pTab->zName));
+        }else{
+          VdbeComment((v,"%s.%s",
+              pTab->zName, pTab->aCol[pCol->iColumn].zCnName));
+          if( pTab->aCol[pCol->iColumn].affinity==SQLITE_AFF_REAL ){
+            sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
+          }
+        }
+        return target;
+      }else if( pExpr->y.pTab==0 ){
+        /* This case happens when the argument to an aggregate function
+        ** is rewritten by aggregateConvertIndexedExprRefToColumn() */
+        sqlite3VdbeAddOp3(v, OP_Column, pExpr->iTable, pExpr->iColumn, target);
+        return target;
+      }
+      /* Otherwise, fall thru into the TK_COLUMN case */
+      /* no break */ deliberate_fall_through
+    }
+    case TK_COLUMN: {
+      int iTab = pExpr->iTable;
+      int iReg;
+      if( ExprHasProperty(pExpr, EP_FixedCol) ){
+        /* This COLUMN expression is really a constant due to WHERE clause
+        ** constraints, and that constant is coded by the pExpr->pLeft
+        ** expression.  However, make sure the constant has the correct
+        ** datatype by applying the Affinity of the table column to the
+        ** constant.
+        */
+        int aff;
+        iReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft,target);
+        assert( ExprUseYTab(pExpr) );
+        assert( pExpr->y.pTab!=0 );
+        aff = sqlite3TableColumnAffinity(pExpr->y.pTab, pExpr->iColumn);
+        if( aff>SQLITE_AFF_BLOB ){
+          static const char zAff[] = "B\000C\000D\000E\000F";
+          assert( SQLITE_AFF_BLOB=='A' );
+          assert( SQLITE_AFF_TEXT=='B' );
+          sqlite3VdbeAddOp4(v, OP_Affinity, iReg, 1, 0,
+                            &zAff[(aff-'B')*2], P4_STATIC);
+        }
+        return iReg;
+      }
+      if( iTab<0 ){
+        if( pParse->iSelfTab<0 ){
+          /* Other columns in the same row for CHECK constraints or
+          ** generated columns or for inserting into partial index.
+          ** The row is unpacked into registers beginning at
+          ** 0-(pParse->iSelfTab).  The rowid (if any) is in a register
+          ** immediately prior to the first column.
+          */
+          Column *pCol;
+          Table *pTab;
+          int iSrc;
+          int iCol = pExpr->iColumn;
+          assert( ExprUseYTab(pExpr) );
+          pTab = pExpr->y.pTab;
+          assert( pTab!=0 );
+          assert( iCol>=XN_ROWID );
+          assert( iCol<pTab->nCol );
+          if( iCol<0 ){
+            return -1-pParse->iSelfTab;
+          }
+          pCol = pTab->aCol + iCol;
+          testcase( iCol!=sqlite3TableColumnToStorage(pTab,iCol) );
+          iSrc = sqlite3TableColumnToStorage(pTab, iCol) - pParse->iSelfTab;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+          if( pCol->colFlags & COLFLAG_GENERATED ){
+            if( pCol->colFlags & COLFLAG_BUSY ){
+              sqlite3ErrorMsg(pParse, "generated column loop on \"%s\"",
+                              pCol->zCnName);
+              return 0;
+            }
+            pCol->colFlags |= COLFLAG_BUSY;
+            if( pCol->colFlags & COLFLAG_NOTAVAIL ){
+              sqlite3ExprCodeGeneratedColumn(pParse, pTab, pCol, iSrc);
+            }
+            pCol->colFlags &= ~(COLFLAG_BUSY|COLFLAG_NOTAVAIL);
+            return iSrc;
+          }else
+#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
+          if( pCol->affinity==SQLITE_AFF_REAL ){
+            sqlite3VdbeAddOp2(v, OP_SCopy, iSrc, target);
+            sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
+            return target;
+          }else{
+            return iSrc;
+          }
+        }else{
+          /* Coding an expression that is part of an index where column names
+          ** in the index refer to the table to which the index belongs */
+          iTab = pParse->iSelfTab - 1;
+        }
+      }
+      else if( pParse->pIdxPartExpr
+       && 0!=(r1 = exprPartidxExprLookup(pParse, pExpr, target))
+      ){
+        return r1;
+      }
+      assert( ExprUseYTab(pExpr) );
+      assert( pExpr->y.pTab!=0 );
+      iReg = sqlite3ExprCodeGetColumn(pParse, pExpr->y.pTab,
+                               pExpr->iColumn, iTab, target,
+                               pExpr->op2);
+      return iReg;
+    }
+    case TK_INTEGER: {
+      codeInteger(pParse, pExpr, 0, target);
+      return target;
+    }
+    case TK_TRUEFALSE: {
+      sqlite3VdbeAddOp2(v, OP_Integer, sqlite3ExprTruthValue(pExpr), target);
+      return target;
+    }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    case TK_FLOAT: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      codeReal(v, pExpr->u.zToken, 0, target);
+      return target;
+    }
+#endif
+    case TK_STRING: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3VdbeLoadString(v, target, pExpr->u.zToken);
+      return target;
+    }
+    default: {
+      /* Make NULL the default case so that if a bug causes an illegal
+      ** Expr node to be passed into this function, it will be handled
+      ** sanely and not crash.  But keep the assert() to bring the problem
+      ** to the attention of the developers. */
+      assert( op==TK_NULL || op==TK_ERROR || pParse->db->mallocFailed );
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      return target;
+    }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case TK_BLOB: {
+      int n;
+      const char *z;
+      char *zBlob;
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
+      assert( pExpr->u.zToken[1]=='\'' );
+      z = &pExpr->u.zToken[2];
+      n = sqlite3Strlen30(z) - 1;
+      assert( z[n]=='\'' );
+      zBlob = sqlite3HexToBlob(sqlite3VdbeDb(v), z, n);
+      sqlite3VdbeAddOp4(v, OP_Blob, n/2, target, 0, zBlob, P4_DYNAMIC);
+      return target;
+    }
+#endif
+    case TK_VARIABLE: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      assert( pExpr->u.zToken!=0 );
+      assert( pExpr->u.zToken[0]!=0 );
+      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iColumn, target);
+      return target;
+    }
+    case TK_REGISTER: {
+      return pExpr->iTable;
+    }
+#ifndef SQLITE_OMIT_CAST
+    case TK_CAST: {
+      /* Expressions of the form:   CAST(pLeft AS token) */
+      sqlite3ExprCode(pParse, pExpr->pLeft, target);
+      assert( inReg==target );
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3VdbeAddOp2(v, OP_Cast, target,
+                        sqlite3AffinityType(pExpr->u.zToken, 0));
+      return inReg;
+    }
+#endif /* SQLITE_OMIT_CAST */
+    case TK_IS:
+    case TK_ISNOT:
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      p5 = SQLITE_NULLEQ;
+      /* fall-through */
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      Expr *pLeft = pExpr->pLeft;
+      if( sqlite3ExprIsVector(pLeft) ){
+        codeVectorCompare(pParse, pExpr, target, op, p5);
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pLeft, ®Free1);
+        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, ®Free2);
+        sqlite3VdbeAddOp2(v, OP_Integer, 1, inReg);
+        codeCompare(pParse, pLeft, pExpr->pRight, op, r1, r2,
+            sqlite3VdbeCurrentAddr(v)+2, p5,
+            ExprHasProperty(pExpr,EP_Commuted));
+        assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+        assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+        assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+        assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+        assert(TK_EQ==OP_Eq); testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
+        assert(TK_NE==OP_Ne); testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
+        if( p5==SQLITE_NULLEQ ){
+          sqlite3VdbeAddOp2(v, OP_Integer, 0, inReg);
+        }else{
+          sqlite3VdbeAddOp3(v, OP_ZeroOrNull, r1, inReg, r2);
+        }
+        testcase( regFree1==0 );
+        testcase( regFree2==0 );
+      }
+      break;
+    }
+    case TK_AND:
+    case TK_OR:
+    case TK_PLUS:
+    case TK_STAR:
+    case TK_MINUS:
+    case TK_REM:
+    case TK_BITAND:
+    case TK_BITOR:
+    case TK_SLASH:
+    case TK_LSHIFT:
+    case TK_RSHIFT:
+    case TK_CONCAT: {
+      assert( TK_AND==OP_And );            testcase( op==TK_AND );
+      assert( TK_OR==OP_Or );              testcase( op==TK_OR );
+      assert( TK_PLUS==OP_Add );           testcase( op==TK_PLUS );
+      assert( TK_MINUS==OP_Subtract );     testcase( op==TK_MINUS );
+      assert( TK_REM==OP_Remainder );      testcase( op==TK_REM );
+      assert( TK_BITAND==OP_BitAnd );      testcase( op==TK_BITAND );
+      assert( TK_BITOR==OP_BitOr );        testcase( op==TK_BITOR );
+      assert( TK_SLASH==OP_Divide );       testcase( op==TK_SLASH );
+      assert( TK_LSHIFT==OP_ShiftLeft );   testcase( op==TK_LSHIFT );
+      assert( TK_RSHIFT==OP_ShiftRight );  testcase( op==TK_RSHIFT );
+      assert( TK_CONCAT==OP_Concat );      testcase( op==TK_CONCAT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, ®Free2);
+      sqlite3VdbeAddOp3(v, op, r2, r1, target);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_UMINUS: {
+      Expr *pLeft = pExpr->pLeft;
+      assert( pLeft );
+      if( pLeft->op==TK_INTEGER ){
+        codeInteger(pParse, pLeft, 1, target);
+        return target;
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      }else if( pLeft->op==TK_FLOAT ){
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        codeReal(v, pLeft->u.zToken, 1, target);
+        return target;
+#endif
+      }else{
+        tempX.op = TK_INTEGER;
+        tempX.flags = EP_IntValue|EP_TokenOnly;
+        tempX.u.iValue = 0;
+        ExprClearVVAProperties(&tempX);
+        r1 = sqlite3ExprCodeTemp(pParse, &tempX, ®Free1);
+        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free2);
+        sqlite3VdbeAddOp3(v, OP_Subtract, r2, r1, target);
+        testcase( regFree2==0 );
+      }
+      break;
+    }
+    case TK_BITNOT:
+    case TK_NOT: {
+      assert( TK_BITNOT==OP_BitNot );   testcase( op==TK_BITNOT );
+      assert( TK_NOT==OP_Not );         testcase( op==TK_NOT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      testcase( regFree1==0 );
+      sqlite3VdbeAddOp2(v, op, r1, inReg);
+      break;
+    }
+    case TK_TRUTH: {
+      int isTrue;    /* IS TRUE or IS NOT TRUE */
+      int bNormal;   /* IS TRUE or IS FALSE */
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      testcase( regFree1==0 );
+      isTrue = sqlite3ExprTruthValue(pExpr->pRight);
+      bNormal = pExpr->op2==TK_IS;
+      testcase( isTrue && bNormal);
+      testcase( !isTrue && bNormal);
+      sqlite3VdbeAddOp4Int(v, OP_IsTrue, r1, inReg, !isTrue, isTrue ^ bNormal);
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      int addr;
+      assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
+      assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      testcase( regFree1==0 );
+      addr = sqlite3VdbeAddOp1(v, op, r1);
+      VdbeCoverageIf(v, op==TK_ISNULL);
+      VdbeCoverageIf(v, op==TK_NOTNULL);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, target);
+      sqlite3VdbeJumpHere(v, addr);
+      break;
+    }
+    case TK_AGG_FUNCTION: {
+      AggInfo *pInfo = pExpr->pAggInfo;
+      if( pInfo==0
+       || NEVER(pExpr->iAgg<0)
+       || NEVER(pExpr->iAgg>=pInfo->nFunc)
+      ){
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        sqlite3ErrorMsg(pParse, "misuse of aggregate: %#T()", pExpr);
+      }else{
+        return AggInfoFuncReg(pInfo, pExpr->iAgg);
+      }
+      break;
+    }
+    case TK_FUNCTION: {
+      ExprList *pFarg;       /* List of function arguments */
+      int nFarg;             /* Number of function arguments */
+      FuncDef *pDef;         /* The function definition object */
+      const char *zId;       /* The function name */
+      u32 constMask = 0;     /* Mask of function arguments that are constant */
+      int i;                 /* Loop counter */
+      sqlite3 *db = pParse->db;  /* The database connection */
+      u8 enc = ENC(db);      /* The text encoding used by this database */
+      CollSeq *pColl = 0;    /* A collating sequence */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( ExprHasProperty(pExpr, EP_WinFunc) ){
+        return pExpr->y.pWin->regResult;
+      }
+#endif
+
+      if( ConstFactorOk(pParse)
+       && sqlite3ExprIsConstantNotJoin(pParse,pExpr)
+      ){
+        /* SQL functions can be expensive. So try to avoid running them
+        ** multiple times if we know they always give the same result */
+        return sqlite3ExprCodeRunJustOnce(pParse, pExpr, -1);
+      }
+      assert( !ExprHasProperty(pExpr, EP_TokenOnly) );
+      assert( ExprUseXList(pExpr) );
+      pFarg = pExpr->x.pList;
+      nFarg = pFarg ? pFarg->nExpr : 0;
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      zId = pExpr->u.zToken;
+      pDef = sqlite3FindFunction(db, zId, nFarg, enc, 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+      if( pDef==0 && pParse->explain ){
+        pDef = sqlite3FindFunction(db, "unknown", nFarg, enc, 0);
+      }
+#endif
+      if( pDef==0 || pDef->xFinalize!=0 ){
+        sqlite3ErrorMsg(pParse, "unknown function: %#T()", pExpr);
+        break;
+      }
+      if( (pDef->funcFlags & SQLITE_FUNC_INLINE)!=0 && ALWAYS(pFarg!=0) ){
+        assert( (pDef->funcFlags & SQLITE_FUNC_UNSAFE)==0 );
+        assert( (pDef->funcFlags & SQLITE_FUNC_DIRECT)==0 );
+        return exprCodeInlineFunction(pParse, pFarg,
+             SQLITE_PTR_TO_INT(pDef->pUserData), target);
+      }else if( pDef->funcFlags & (SQLITE_FUNC_DIRECT|SQLITE_FUNC_UNSAFE) ){
+        sqlite3ExprFunctionUsable(pParse, pExpr, pDef);
+      }
+
+      for(i=0; i<nFarg; i++){
+        if( i<32 && sqlite3ExprIsConstant(pParse, pFarg->a[i].pExpr) ){
+          testcase( i==31 );
+          constMask |= MASKBIT32(i);
+        }
+        if( (pDef->funcFlags & SQLITE_FUNC_NEEDCOLL)!=0 && !pColl ){
+          pColl = sqlite3ExprCollSeq(pParse, pFarg->a[i].pExpr);
+        }
+      }
+      if( pFarg ){
+        if( constMask ){
+          r1 = pParse->nMem+1;
+          pParse->nMem += nFarg;
+        }else{
+          r1 = sqlite3GetTempRange(pParse, nFarg);
+        }
+
+        /* For length() and typeof() and octet_length() functions,
+        ** set the P5 parameter to the OP_Column opcode to OPFLAG_LENGTHARG
+        ** or OPFLAG_TYPEOFARG or OPFLAG_BYTELENARG respectively, to avoid
+        ** unnecessary data loading.
+        */
+        if( (pDef->funcFlags & (SQLITE_FUNC_LENGTH|SQLITE_FUNC_TYPEOF))!=0 ){
+          u8 exprOp;
+          assert( nFarg==1 );
+          assert( pFarg->a[0].pExpr!=0 );
+          exprOp = pFarg->a[0].pExpr->op;
+          if( exprOp==TK_COLUMN || exprOp==TK_AGG_COLUMN ){
+            assert( SQLITE_FUNC_LENGTH==OPFLAG_LENGTHARG );
+            assert( SQLITE_FUNC_TYPEOF==OPFLAG_TYPEOFARG );
+            assert( SQLITE_FUNC_BYTELEN==OPFLAG_BYTELENARG );
+            assert( (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG)==OPFLAG_BYTELENARG );
+            testcase( (pDef->funcFlags & OPFLAG_BYTELENARG)==OPFLAG_LENGTHARG );
+            testcase( (pDef->funcFlags & OPFLAG_BYTELENARG)==OPFLAG_TYPEOFARG );
+            testcase( (pDef->funcFlags & OPFLAG_BYTELENARG)==OPFLAG_BYTELENARG);
+            pFarg->a[0].pExpr->op2 = pDef->funcFlags & OPFLAG_BYTELENARG;
+          }
+        }
+
+        sqlite3ExprCodeExprList(pParse, pFarg, r1, 0, SQLITE_ECEL_FACTOR);
+      }else{
+        r1 = 0;
+      }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      /* Possibly overload the function if the first argument is
+      ** a virtual table column.
+      **
+      ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
+      ** second argument, not the first, as the argument to test to
+      ** see if it is a column in a virtual table.  This is done because
+      ** the left operand of infix functions (the operand we want to
+      ** control overloading) ends up as the second argument to the
+      ** function.  The expression "A glob B" is equivalent to
+      ** "glob(B,A).  We want to use the A in "A glob B" to test
+      ** for function overloading.  But we use the B term in "glob(B,A)".
+      */
+      if( nFarg>=2 && ExprHasProperty(pExpr, EP_InfixFunc) ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[1].pExpr);
+      }else if( nFarg>0 ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[0].pExpr);
+      }
+#endif
+      if( pDef->funcFlags & SQLITE_FUNC_NEEDCOLL ){
+        if( !pColl ) pColl = db->pDfltColl;
+        sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
+      }
+      sqlite3VdbeAddFunctionCall(pParse, constMask, r1, target, nFarg,
+                                 pDef, pExpr->op2);
+      if( nFarg ){
+        if( constMask==0 ){
+          sqlite3ReleaseTempRange(pParse, r1, nFarg);
+        }else{
+          sqlite3VdbeReleaseRegisters(pParse, r1, nFarg, constMask, 1);
+        }
+      }
+      return target;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_EXISTS:
+    case TK_SELECT: {
+      int nCol;
+      testcase( op==TK_EXISTS );
+      testcase( op==TK_SELECT );
+      if( pParse->db->mallocFailed ){
+        return 0;
+      }else if( op==TK_SELECT
+             && ALWAYS( ExprUseXSelect(pExpr) )
+             && (nCol = pExpr->x.pSelect->pEList->nExpr)!=1
+      ){
+        sqlite3SubselectError(pParse, nCol, 1);
+      }else{
+        return sqlite3CodeSubselect(pParse, pExpr);
+      }
+      break;
+    }
+    case TK_SELECT_COLUMN: {
+      int n;
+      Expr *pLeft = pExpr->pLeft;
+      if( pLeft->iTable==0 || pParse->withinRJSubrtn > pLeft->op2 ){
+        pLeft->iTable = sqlite3CodeSubselect(pParse, pLeft);
+        pLeft->op2 = pParse->withinRJSubrtn;
+      }
+      assert( pLeft->op==TK_SELECT || pLeft->op==TK_ERROR );
+      n = sqlite3ExprVectorSize(pLeft);
+      if( pExpr->iTable!=n ){
+        sqlite3ErrorMsg(pParse, "%d columns assigned %d values",
+                                pExpr->iTable, n);
+      }
+      return pLeft->iTable + pExpr->iColumn;
+    }
+    case TK_IN: {
+      int destIfFalse = sqlite3VdbeMakeLabel(pParse);
+      int destIfNull = sqlite3VdbeMakeLabel(pParse);
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      sqlite3VdbeAddOp2(v, OP_AddImm, target, 0);
+      sqlite3VdbeResolveLabel(v, destIfNull);
+      return target;
+    }
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+
+    /*
+    **    x BETWEEN y AND z
+    **
+    ** This is equivalent to
+    **
+    **    x>=y AND x<=z
+    **
+    ** X is stored in pExpr->pLeft.
+    ** Y is stored in pExpr->pList->a[0].pExpr.
+    ** Z is stored in pExpr->pList->a[1].pExpr.
+    */
+    case TK_BETWEEN: {
+      exprCodeBetween(pParse, pExpr, target, 0, 0);
+      return target;
+    }
+    case TK_COLLATE: {
+      if( !ExprHasProperty(pExpr, EP_Collate) ){
+        /* A TK_COLLATE Expr node without the EP_Collate tag is a so-called
+        ** "SOFT-COLLATE" that is added to constraints that are pushed down
+        ** from outer queries into sub-queries by the WHERE-clause push-down
+        ** optimization. Clear subtypes as subtypes may not cross a subquery
+        ** boundary.
+        */
+        assert( pExpr->pLeft );
+        sqlite3ExprCode(pParse, pExpr->pLeft, target);
+        sqlite3VdbeAddOp1(v, OP_ClrSubtype, target);
+        return target;
+      }else{
+        pExpr = pExpr->pLeft;
+        goto expr_code_doover; /* 2018-04-28: Prevent deep recursion. */
+      }
+    }
+    case TK_SPAN:
+    case TK_UPLUS: {
+      pExpr = pExpr->pLeft;
+      goto expr_code_doover; /* 2018-04-28: Prevent deep recursion. OSSFuzz. */
+    }
+
+    case TK_TRIGGER: {
+      /* If the opcode is TK_TRIGGER, then the expression is a reference
+      ** to a column in the new.* or old.* pseudo-tables available to
+      ** trigger programs. In this case Expr.iTable is set to 1 for the
+      ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
+      ** is set to the column of the pseudo-table to read, or to -1 to
+      ** read the rowid field.
+      **
+      ** The expression is implemented using an OP_Param opcode. The p1
+      ** parameter is set to 0 for an old.rowid reference, or to (i+1)
+      ** to reference another column of the old.* pseudo-table, where
+      ** i is the index of the column. For a new.rowid reference, p1 is
+      ** set to (n+1), where n is the number of columns in each pseudo-table.
+      ** For a reference to any other column in the new.* pseudo-table, p1
+      ** is set to (n+2+i), where n and i are as defined previously. For
+      ** example, if the table on which triggers are being fired is
+      ** declared as:
+      **
+      **   CREATE TABLE t1(a, b);
+      **
+      ** Then p1 is interpreted as follows:
+      **
+      **   p1==0   ->    old.rowid     p1==3   ->    new.rowid
+      **   p1==1   ->    old.a         p1==4   ->    new.a
+      **   p1==2   ->    old.b         p1==5   ->    new.b
+      */
+      Table *pTab;
+      int iCol;
+      int p1;
+
+      assert( ExprUseYTab(pExpr) );
+      pTab = pExpr->y.pTab;
+      iCol = pExpr->iColumn;
+      p1 = pExpr->iTable * (pTab->nCol+1) + 1
+                     + sqlite3TableColumnToStorage(pTab, iCol);
+
+      assert( pExpr->iTable==0 || pExpr->iTable==1 );
+      assert( iCol>=-1 && iCol<pTab->nCol );
+      assert( pTab->iPKey<0 || iCol!=pTab->iPKey );
+      assert( p1>=0 && p1<(pTab->nCol*2+2) );
+
+      sqlite3VdbeAddOp2(v, OP_Param, p1, target);
+      VdbeComment((v, "r[%d]=%s.%s", target,
+        (pExpr->iTable ? "new" : "old"),
+        (pExpr->iColumn<0 ? "rowid" : pExpr->y.pTab->aCol[iCol].zCnName)
+      ));
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      /* If the column has REAL affinity, it may currently be stored as an
+      ** integer. Use OP_RealAffinity to make sure it is really real.
+      **
+      ** EVIDENCE-OF: R-60985-57662 SQLite will convert the value back to
+      ** floating point when extracting it from the record.  */
+      if( iCol>=0 && pTab->aCol[iCol].affinity==SQLITE_AFF_REAL ){
+        sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
+      }
+#endif
+      break;
+    }
+
+    case TK_VECTOR: {
+      sqlite3ErrorMsg(pParse, "row value misused");
+      break;
+    }
+
+    /* TK_IF_NULL_ROW Expr nodes are inserted ahead of expressions
+    ** that derive from the right-hand table of a LEFT JOIN.  The
+    ** Expr.iTable value is the table number for the right-hand table.
+    ** The expression is only evaluated if that table is not currently
+    ** on a LEFT JOIN NULL row.
+    */
+    case TK_IF_NULL_ROW: {
+      int addrINR;
+      u8 okConstFactor = pParse->okConstFactor;
+      AggInfo *pAggInfo = pExpr->pAggInfo;
+      if( pAggInfo ){
+        assert( pExpr->iAgg>=0 && pExpr->iAgg<pAggInfo->nColumn );
+        if( !pAggInfo->directMode ){
+          inReg = AggInfoColumnReg(pAggInfo, pExpr->iAgg);
+          break;
+        }
+        if( pExpr->pAggInfo->useSortingIdx ){
+          sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdxPTab,
+                            pAggInfo->aCol[pExpr->iAgg].iSorterColumn,
+                            target);
+          inReg = target;
+          break;
+        }
+      }
+      addrINR = sqlite3VdbeAddOp3(v, OP_IfNullRow, pExpr->iTable, 0, target);
+      /* The OP_IfNullRow opcode above can overwrite the result register with
+      ** NULL.  So we have to ensure that the result register is not a value
+      ** that is suppose to be a constant.  Two defenses are needed:
+      **   (1)  Temporarily disable factoring of constant expressions
+      **   (2)  Make sure the computed value really is stored in register
+      **        "target" and not someplace else.
+      */
+      pParse->okConstFactor = 0;   /* note (1) above */
+      sqlite3ExprCode(pParse, pExpr->pLeft, target);
+      assert( target==inReg );
+      pParse->okConstFactor = okConstFactor;
+      sqlite3VdbeJumpHere(v, addrINR);
+      break;
+    }
+
+    /*
+    ** Form A:
+    **   CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
+    **
+    ** Form B:
+    **   CASE WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
+    **
+    ** Form A is can be transformed into the equivalent form B as follows:
+    **   CASE WHEN x=e1 THEN r1 WHEN x=e2 THEN r2 ...
+    **        WHEN x=eN THEN rN ELSE y END
+    **
+    ** X (if it exists) is in pExpr->pLeft.
+    ** Y is in the last element of pExpr->x.pList if pExpr->x.pList->nExpr is
+    ** odd.  The Y is also optional.  If the number of elements in x.pList
+    ** is even, then Y is omitted and the "otherwise" result is NULL.
+    ** Ei is in pExpr->pList->a[i*2] and Ri is pExpr->pList->a[i*2+1].
+    **
+    ** The result of the expression is the Ri for the first matching Ei,
+    ** or if there is no matching Ei, the ELSE term Y, or if there is
+    ** no ELSE term, NULL.
+    */
+    case TK_CASE: {
+      int endLabel;                     /* GOTO label for end of CASE stmt */
+      int nextCase;                     /* GOTO label for next WHEN clause */
+      int nExpr;                        /* 2x number of WHEN terms */
+      int i;                            /* Loop counter */
+      ExprList *pEList;                 /* List of WHEN terms */
+      struct ExprList_item *aListelem;  /* Array of WHEN terms */
+      Expr opCompare;                   /* The X==Ei expression */
+      Expr *pX;                         /* The X expression */
+      Expr *pTest = 0;                  /* X==Ei (form A) or just Ei (form B) */
+      Expr *pDel = 0;
+      sqlite3 *db = pParse->db;
+
+      assert( ExprUseXList(pExpr) && pExpr->x.pList!=0 );
+      assert(pExpr->x.pList->nExpr > 0);
+      pEList = pExpr->x.pList;
+      aListelem = pEList->a;
+      nExpr = pEList->nExpr;
+      endLabel = sqlite3VdbeMakeLabel(pParse);
+      if( (pX = pExpr->pLeft)!=0 ){
+        pDel = sqlite3ExprDup(db, pX, 0);
+        if( db->mallocFailed ){
+          sqlite3ExprDelete(db, pDel);
+          break;
+        }
+        testcase( pX->op==TK_COLUMN );
+        sqlite3ExprToRegister(pDel, exprCodeVector(pParse, pDel, ®Free1));
+        testcase( regFree1==0 );
+        memset(&opCompare, 0, sizeof(opCompare));
+        opCompare.op = TK_EQ;
+        opCompare.pLeft = pDel;
+        pTest = &opCompare;
+        /* Ticket b351d95f9cd5ef17e9d9dbae18f5ca8611190001:
+        ** The value in regFree1 might get SCopy-ed into the file result.
+        ** So make sure that the regFree1 register is not reused for other
+        ** purposes and possibly overwritten.  */
+        regFree1 = 0;
+      }
+      for(i=0; i<nExpr-1; i=i+2){
+        if( pX ){
+          assert( pTest!=0 );
+          opCompare.pRight = aListelem[i].pExpr;
+        }else{
+          pTest = aListelem[i].pExpr;
+        }
+        nextCase = sqlite3VdbeMakeLabel(pParse);
+        testcase( pTest->op==TK_COLUMN );
+        sqlite3ExprIfFalse(pParse, pTest, nextCase, SQLITE_JUMPIFNULL);
+        testcase( aListelem[i+1].pExpr->op==TK_COLUMN );
+        sqlite3ExprCode(pParse, aListelem[i+1].pExpr, target);
+        sqlite3VdbeGoto(v, endLabel);
+        sqlite3VdbeResolveLabel(v, nextCase);
+      }
+      if( (nExpr&1)!=0 ){
+        sqlite3ExprCode(pParse, pEList->a[nExpr-1].pExpr, target);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      }
+      sqlite3ExprDelete(db, pDel);
+      setDoNotMergeFlagOnCopy(v);
+      sqlite3VdbeResolveLabel(v, endLabel);
+      break;
+    }
+#ifndef SQLITE_OMIT_TRIGGER
+    case TK_RAISE: {
+      assert( pExpr->affExpr==OE_Rollback
+           || pExpr->affExpr==OE_Abort
+           || pExpr->affExpr==OE_Fail
+           || pExpr->affExpr==OE_Ignore
+      );
+      if( !pParse->pTriggerTab && !pParse->nested ){
+        sqlite3ErrorMsg(pParse,
+                       "RAISE() may only be used within a trigger-program");
+        return 0;
+      }
+      if( pExpr->affExpr==OE_Abort ){
+        sqlite3MayAbort(pParse);
+      }
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      if( pExpr->affExpr==OE_Ignore ){
+        sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, OE_Ignore);
+        VdbeCoverage(v);
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+        sqlite3VdbeAddOp3(v, OP_Halt,
+             pParse->pTriggerTab ? SQLITE_CONSTRAINT_TRIGGER : SQLITE_ERROR,
+             pExpr->affExpr, r1);
+      }
+      break;
+    }
+#endif
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+  return inReg;
+}
+
+/*
+** Generate code that will evaluate expression pExpr just one time
+** per prepared statement execution.
+**
+** If the expression uses functions (that might throw an exception) then
+** guard them with an OP_Once opcode to ensure that the code is only executed
+** once. If no functions are involved, then factor the code out and put it at
+** the end of the prepared statement in the initialization section.
+**
+** If regDest>0 then the result is always stored in that register and the
+** result is not reusable.  If regDest<0 then this routine is free to
+** store the value wherever it wants.  The register where the expression
+** is stored is returned.  When regDest<0, two identical expressions might
+** code to the same register, if they do not contain function calls and hence
+** are factored out into the initialization section at the end of the
+** prepared statement.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeRunJustOnce(
+  Parse *pParse,    /* Parsing context */
+  Expr *pExpr,      /* The expression to code when the VDBE initializes */
+  int regDest       /* Store the value in this register */
+){
+  ExprList *p;
+  assert( ConstFactorOk(pParse) );
+  assert( regDest!=0 );
+  p = pParse->pConstExpr;
+  if( regDest<0 && p ){
+    struct ExprList_item *pItem;
+    int i;
+    for(pItem=p->a, i=p->nExpr; i>0; pItem++, i--){
+      if( pItem->fg.reusable
+       && sqlite3ExprCompare(0,pItem->pExpr,pExpr,-1)==0
+      ){
+        return pItem->u.iConstExprReg;
+      }
+    }
+  }
+  pExpr = sqlite3ExprDup(pParse->db, pExpr, 0);
+  if( pExpr!=0 && ExprHasProperty(pExpr, EP_HasFunc) ){
+    Vdbe *v = pParse->pVdbe;
+    int addr;
+    assert( v );
+    addr = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+    pParse->okConstFactor = 0;
+    if( !pParse->db->mallocFailed ){
+      if( regDest<0 ) regDest = ++pParse->nMem;
+      sqlite3ExprCode(pParse, pExpr, regDest);
+    }
+    pParse->okConstFactor = 1;
+    sqlite3ExprDelete(pParse->db, pExpr);
+    sqlite3VdbeJumpHere(v, addr);
+  }else{
+    p = sqlite3ExprListAppend(pParse, p, pExpr);
+    if( p ){
+       struct ExprList_item *pItem = &p->a[p->nExpr-1];
+       pItem->fg.reusable = regDest<0;
+       if( regDest<0 ) regDest = ++pParse->nMem;
+       pItem->u.iConstExprReg = regDest;
+    }
+    pParse->pConstExpr = p;
+  }
+  return regDest;
+}
+
+/*
+** Generate code to evaluate an expression and store the results
+** into a register.  Return the register number where the results
+** are stored.
+**
+** If the register is a temporary register that can be deallocated,
+** then write its number into *pReg.  If the result register is not
+** a temporary, then set *pReg to zero.
+**
+** If pExpr is a constant, then this routine might generate this
+** code to fill the register in the initialization section of the
+** VDBE program, in order to factor it out of the evaluation loop.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeTemp(Parse *pParse, Expr *pExpr, int *pReg){
+  int r2;
+  pExpr = sqlite3ExprSkipCollateAndLikely(pExpr);
+  if( ConstFactorOk(pParse)
+   && ALWAYS(pExpr!=0)
+   && pExpr->op!=TK_REGISTER
+   && sqlite3ExprIsConstantNotJoin(pParse, pExpr)
+  ){
+    *pReg  = 0;
+    r2 = sqlite3ExprCodeRunJustOnce(pParse, pExpr, -1);
+  }else{
+    int r1 = sqlite3GetTempReg(pParse);
+    r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
+    if( r2==r1 ){
+      *pReg = r1;
+    }else{
+      sqlite3ReleaseTempReg(pParse, r1);
+      *pReg = 0;
+    }
+  }
+  return r2;
+}
+
+/*
+** Generate code that will evaluate expression pExpr and store the
+** results in register target.  The results are guaranteed to appear
+** in register target.
+*/
+SQLITE_PRIVATE void sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
+  int inReg;
+
+  assert( pExpr==0 || !ExprHasVVAProperty(pExpr,EP_Immutable) );
+  assert( target>0 && target<=pParse->nMem );
+  assert( pParse->pVdbe!=0 || pParse->db->mallocFailed );
+  if( pParse->pVdbe==0 ) return;
+  inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
+  if( inReg!=target ){
+    u8 op;
+    Expr *pX = sqlite3ExprSkipCollateAndLikely(pExpr);
+    testcase( pX!=pExpr );
+    if( ALWAYS(pX)
+     && (ExprHasProperty(pX,EP_Subquery) || pX->op==TK_REGISTER)
+    ){
+      op = OP_Copy;
+    }else{
+      op = OP_SCopy;
+    }
+    sqlite3VdbeAddOp2(pParse->pVdbe, op, inReg, target);
+  }
+}
+
+/*
+** Make a transient copy of expression pExpr and then code it using
+** sqlite3ExprCode().  This routine works just like sqlite3ExprCode()
+** except that the input expression is guaranteed to be unchanged.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeCopy(Parse *pParse, Expr *pExpr, int target){
+  sqlite3 *db = pParse->db;
+  pExpr = sqlite3ExprDup(db, pExpr, 0);
+  if( !db->mallocFailed ) sqlite3ExprCode(pParse, pExpr, target);
+  sqlite3ExprDelete(db, pExpr);
+}
+
+/*
+** Generate code that will evaluate expression pExpr and store the
+** results in register target.  The results are guaranteed to appear
+** in register target.  If the expression is constant, then this routine
+** might choose to code the expression at initialization time.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeFactorable(Parse *pParse, Expr *pExpr, int target){
+  if( pParse->okConstFactor && sqlite3ExprIsConstantNotJoin(pParse,pExpr) ){
+    sqlite3ExprCodeRunJustOnce(pParse, pExpr, target);
+  }else{
+    sqlite3ExprCodeCopy(pParse, pExpr, target);
+  }
+}
+
+/*
+** Generate code that pushes the value of every element of the given
+** expression list into a sequence of registers beginning at target.
+**
+** Return the number of elements evaluated.  The number returned will
+** usually be pList->nExpr but might be reduced if SQLITE_ECEL_OMITREF
+** is defined.
+**
+** The SQLITE_ECEL_DUP flag prevents the arguments from being
+** filled using OP_SCopy.  OP_Copy must be used instead.
+**
+** The SQLITE_ECEL_FACTOR argument allows constant arguments to be
+** factored out into initialization code.
+**
+** The SQLITE_ECEL_REF flag means that expressions in the list with
+** ExprList.a[].u.x.iOrderByCol>0 have already been evaluated and stored
+** in registers at srcReg, and so the value can be copied from there.
+** If SQLITE_ECEL_OMITREF is also set, then the values with u.x.iOrderByCol>0
+** are simply omitted rather than being copied from srcReg.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeExprList(
+  Parse *pParse,     /* Parsing context */
+  ExprList *pList,   /* The expression list to be coded */
+  int target,        /* Where to write results */
+  int srcReg,        /* Source registers if SQLITE_ECEL_REF */
+  u8 flags           /* SQLITE_ECEL_* flags */
+){
+  struct ExprList_item *pItem;
+  int i, j, n;
+  u8 copyOp = (flags & SQLITE_ECEL_DUP) ? OP_Copy : OP_SCopy;
+  Vdbe *v = pParse->pVdbe;
+  assert( pList!=0 );
+  assert( target>0 );
+  assert( pParse->pVdbe!=0 );  /* Never gets this far otherwise */
+  n = pList->nExpr;
+  if( !ConstFactorOk(pParse) ) flags &= ~SQLITE_ECEL_FACTOR;
+  for(pItem=pList->a, i=0; i<n; i++, pItem++){
+    Expr *pExpr = pItem->pExpr;
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( pItem->fg.bSorterRef ){
+      i--;
+      n--;
+    }else
+#endif
+    if( (flags & SQLITE_ECEL_REF)!=0 && (j = pItem->u.x.iOrderByCol)>0 ){
+      if( flags & SQLITE_ECEL_OMITREF ){
+        i--;
+        n--;
+      }else{
+        sqlite3VdbeAddOp2(v, copyOp, j+srcReg-1, target+i);
+      }
+    }else if( (flags & SQLITE_ECEL_FACTOR)!=0
+           && sqlite3ExprIsConstantNotJoin(pParse,pExpr)
+    ){
+      sqlite3ExprCodeRunJustOnce(pParse, pExpr, target+i);
+    }else{
+      int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
+      if( inReg!=target+i ){
+        VdbeOp *pOp;
+        if( copyOp==OP_Copy
+         && (pOp=sqlite3VdbeGetLastOp(v))->opcode==OP_Copy
+         && pOp->p1+pOp->p3+1==inReg
+         && pOp->p2+pOp->p3+1==target+i
+         && pOp->p5==0  /* The do-not-merge flag must be clear */
+        ){
+          pOp->p3++;
+        }else{
+          sqlite3VdbeAddOp2(v, copyOp, inReg, target+i);
+        }
+      }
+    }
+  }
+  return n;
+}
+
+/*
+** Generate code for a BETWEEN operator.
+**
+**    x BETWEEN y AND z
+**
+** The above is equivalent to
+**
+**    x>=y AND x<=z
+**
+** Code it as such, taking care to do the common subexpression
+** elimination of x.
+**
+** The xJumpIf parameter determines details:
+**
+**    NULL:                   Store the boolean result in reg[dest]
+**    sqlite3ExprIfTrue:      Jump to dest if true
+**    sqlite3ExprIfFalse:     Jump to dest if false
+**
+** The jumpIfNull parameter is ignored if xJumpIf is NULL.
+*/
+static void exprCodeBetween(
+  Parse *pParse,    /* Parsing and code generating context */
+  Expr *pExpr,      /* The BETWEEN expression */
+  int dest,         /* Jump destination or storage location */
+  void (*xJump)(Parse*,Expr*,int,int), /* Action to take */
+  int jumpIfNull    /* Take the jump if the BETWEEN is NULL */
+){
+  Expr exprAnd;     /* The AND operator in  x>=y AND x<=z  */
+  Expr compLeft;    /* The  x>=y  term */
+  Expr compRight;   /* The  x<=z  term */
+  int regFree1 = 0; /* Temporary use register */
+  Expr *pDel = 0;
+  sqlite3 *db = pParse->db;
+
+  memset(&compLeft, 0, sizeof(Expr));
+  memset(&compRight, 0, sizeof(Expr));
+  memset(&exprAnd, 0, sizeof(Expr));
+
+  assert( ExprUseXList(pExpr) );
+  pDel = sqlite3ExprDup(db, pExpr->pLeft, 0);
+  if( db->mallocFailed==0 ){
+    exprAnd.op = TK_AND;
+    exprAnd.pLeft = &compLeft;
+    exprAnd.pRight = &compRight;
+    compLeft.op = TK_GE;
+    compLeft.pLeft = pDel;
+    compLeft.pRight = pExpr->x.pList->a[0].pExpr;
+    compRight.op = TK_LE;
+    compRight.pLeft = pDel;
+    compRight.pRight = pExpr->x.pList->a[1].pExpr;
+    sqlite3ExprToRegister(pDel, exprCodeVector(pParse, pDel, ®Free1));
+    if( xJump ){
+      xJump(pParse, &exprAnd, dest, jumpIfNull);
+    }else{
+      /* Mark the expression is being from the ON or USING clause of a join
+      ** so that the sqlite3ExprCodeTarget() routine will not attempt to move
+      ** it into the Parse.pConstExpr list.  We should use a new bit for this,
+      ** for clarity, but we are out of bits in the Expr.flags field so we
+      ** have to reuse the EP_OuterON bit.  Bummer. */
+      pDel->flags |= EP_OuterON;
+      sqlite3ExprCodeTarget(pParse, &exprAnd, dest);
+    }
+    sqlite3ReleaseTempReg(pParse, regFree1);
+  }
+  sqlite3ExprDelete(db, pDel);
+
+  /* Ensure adequate test coverage */
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull==0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull==0 && regFree1!=0 );
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull!=0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull!=0 && regFree1!=0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull==0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull==0 && regFree1!=0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull!=0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull!=0 && regFree1!=0 );
+  testcase( xJump==0 );
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is true but execution
+** continues straight thru if the expression is false.
+**
+** If the expression evaluates to NULL (neither true nor false), then
+** take the jump if the jumpIfNull flag is SQLITE_JUMPIFNULL.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align.  Assert()s in the code
+** below verify that the numbers are aligned correctly.
+*/
+SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  int regFree1 = 0;
+  int regFree2 = 0;
+  int r1, r2;
+
+  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
+  if( NEVER(v==0) )     return;  /* Existence of VDBE checked by caller */
+  if( NEVER(pExpr==0) ) return;  /* No way this can happen */
+  assert( !ExprHasVVAProperty(pExpr, EP_Immutable) );
+  op = pExpr->op;
+  switch( op ){
+    case TK_AND:
+    case TK_OR: {
+      Expr *pAlt = sqlite3ExprSimplifiedAndOr(pExpr);
+      if( pAlt!=pExpr ){
+        sqlite3ExprIfTrue(pParse, pAlt, dest, jumpIfNull);
+      }else if( op==TK_AND ){
+        int d2 = sqlite3VdbeMakeLabel(pParse);
+        testcase( jumpIfNull==0 );
+        sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,
+                           jumpIfNull^SQLITE_JUMPIFNULL);
+        sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+        sqlite3VdbeResolveLabel(v, d2);
+      }else{
+        testcase( jumpIfNull==0 );
+        sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+        sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+      }
+      break;
+    }
+    case TK_NOT: {
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_TRUTH: {
+      int isNot;      /* IS NOT TRUE or IS NOT FALSE */
+      int isTrue;     /* IS TRUE or IS NOT TRUE */
+      testcase( jumpIfNull==0 );
+      isNot = pExpr->op2==TK_ISNOT;
+      isTrue = sqlite3ExprTruthValue(pExpr->pRight);
+      testcase( isTrue && isNot );
+      testcase( !isTrue && isNot );
+      if( isTrue ^ isNot ){
+        sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest,
+                          isNot ? SQLITE_JUMPIFNULL : 0);
+      }else{
+        sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest,
+                           isNot ? SQLITE_JUMPIFNULL : 0);
+      }
+      break;
+    }
+    case TK_IS:
+    case TK_ISNOT:
+      testcase( op==TK_IS );
+      testcase( op==TK_ISNOT );
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      jumpIfNull = SQLITE_NULLEQ;
+      /* no break */ deliberate_fall_through
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
+      testcase( jumpIfNull==0 );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, ®Free2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, jumpIfNull, ExprHasProperty(pExpr,EP_Commuted));
+      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+      assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+      assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull==SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull!=SQLITE_NULLEQ);
+      assert(TK_NE==OP_Ne); testcase(op==OP_Ne);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull==SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull!=SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
+      assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      assert( regFree1==0 || regFree1==r1 );
+      if( regFree1 ) sqlite3VdbeTypeofColumn(v, r1);
+      sqlite3VdbeAddOp2(v, op, r1, dest);
+      VdbeCoverageIf(v, op==TK_ISNULL);
+      VdbeCoverageIf(v, op==TK_NOTNULL);
+      break;
+    }
+    case TK_BETWEEN: {
+      testcase( jumpIfNull==0 );
+      exprCodeBetween(pParse, pExpr, dest, sqlite3ExprIfTrue, jumpIfNull);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_IN: {
+      int destIfFalse = sqlite3VdbeMakeLabel(pParse);
+      int destIfNull = jumpIfNull ? dest : destIfFalse;
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeGoto(v, dest);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      break;
+    }
+#endif
+    default: {
+    default_expr:
+      if( ExprAlwaysTrue(pExpr) ){
+        sqlite3VdbeGoto(v, dest);
+      }else if( ExprAlwaysFalse(pExpr) ){
+        /* No-op */
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pExpr, ®Free1);
+        sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0);
+        VdbeCoverage(v);
+        testcase( regFree1==0 );
+        testcase( jumpIfNull==0 );
+      }
+      break;
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is false but execution
+** continues straight thru if the expression is true.
+**
+** If the expression evaluates to NULL (neither true nor false) then
+** jump if jumpIfNull is SQLITE_JUMPIFNULL or fall through if jumpIfNull
+** is 0.
+*/
+SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  int regFree1 = 0;
+  int regFree2 = 0;
+  int r1, r2;
+
+  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
+  if( NEVER(v==0) ) return; /* Existence of VDBE checked by caller */
+  if( pExpr==0 )    return;
+  assert( !ExprHasVVAProperty(pExpr,EP_Immutable) );
+
+  /* The value of pExpr->op and op are related as follows:
+  **
+  **       pExpr->op            op
+  **       ---------          ----------
+  **       TK_ISNULL          OP_NotNull
+  **       TK_NOTNULL         OP_IsNull
+  **       TK_NE              OP_Eq
+  **       TK_EQ              OP_Ne
+  **       TK_GT              OP_Le
+  **       TK_LE              OP_Gt
+  **       TK_GE              OP_Lt
+  **       TK_LT              OP_Ge
+  **
+  ** For other values of pExpr->op, op is undefined and unused.
+  ** The value of TK_ and OP_ constants are arranged such that we
+  ** can compute the mapping above using the following expression.
+  ** Assert()s verify that the computation is correct.
+  */
+  op = ((pExpr->op+(TK_ISNULL&1))^1)-(TK_ISNULL&1);
+
+  /* Verify correct alignment of TK_ and OP_ constants
+  */
+  assert( pExpr->op!=TK_ISNULL || op==OP_NotNull );
+  assert( pExpr->op!=TK_NOTNULL || op==OP_IsNull );
+  assert( pExpr->op!=TK_NE || op==OP_Eq );
+  assert( pExpr->op!=TK_EQ || op==OP_Ne );
+  assert( pExpr->op!=TK_LT || op==OP_Ge );
+  assert( pExpr->op!=TK_LE || op==OP_Gt );
+  assert( pExpr->op!=TK_GT || op==OP_Le );
+  assert( pExpr->op!=TK_GE || op==OP_Lt );
+
+  switch( pExpr->op ){
+    case TK_AND:
+    case TK_OR: {
+      Expr *pAlt = sqlite3ExprSimplifiedAndOr(pExpr);
+      if( pAlt!=pExpr ){
+        sqlite3ExprIfFalse(pParse, pAlt, dest, jumpIfNull);
+      }else if( pExpr->op==TK_AND ){
+        testcase( jumpIfNull==0 );
+        sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+        sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+      }else{
+        int d2 = sqlite3VdbeMakeLabel(pParse);
+        testcase( jumpIfNull==0 );
+        sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2,
+                          jumpIfNull^SQLITE_JUMPIFNULL);
+        sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+        sqlite3VdbeResolveLabel(v, d2);
+      }
+      break;
+    }
+    case TK_NOT: {
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_TRUTH: {
+      int isNot;   /* IS NOT TRUE or IS NOT FALSE */
+      int isTrue;  /* IS TRUE or IS NOT TRUE */
+      testcase( jumpIfNull==0 );
+      isNot = pExpr->op2==TK_ISNOT;
+      isTrue = sqlite3ExprTruthValue(pExpr->pRight);
+      testcase( isTrue && isNot );
+      testcase( !isTrue && isNot );
+      if( isTrue ^ isNot ){
+        /* IS TRUE and IS NOT FALSE */
+        sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest,
+                           isNot ? 0 : SQLITE_JUMPIFNULL);
+
+      }else{
+        /* IS FALSE and IS NOT TRUE */
+        sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest,
+                          isNot ? 0 : SQLITE_JUMPIFNULL);
+      }
+      break;
+    }
+    case TK_IS:
+    case TK_ISNOT:
+      testcase( pExpr->op==TK_IS );
+      testcase( pExpr->op==TK_ISNOT );
+      op = (pExpr->op==TK_IS) ? TK_NE : TK_EQ;
+      jumpIfNull = SQLITE_NULLEQ;
+      /* no break */ deliberate_fall_through
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
+      testcase( jumpIfNull==0 );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, ®Free2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, jumpIfNull,ExprHasProperty(pExpr,EP_Commuted));
+      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+      assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+      assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull!=SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull==SQLITE_NULLEQ);
+      assert(TK_NE==OP_Ne); testcase(op==OP_Ne);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull!=SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull==SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      assert( regFree1==0 || regFree1==r1 );
+      if( regFree1 ) sqlite3VdbeTypeofColumn(v, r1);
+      sqlite3VdbeAddOp2(v, op, r1, dest);
+      testcase( op==TK_ISNULL );   VdbeCoverageIf(v, op==TK_ISNULL);
+      testcase( op==TK_NOTNULL );  VdbeCoverageIf(v, op==TK_NOTNULL);
+      break;
+    }
+    case TK_BETWEEN: {
+      testcase( jumpIfNull==0 );
+      exprCodeBetween(pParse, pExpr, dest, sqlite3ExprIfFalse, jumpIfNull);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_IN: {
+      if( jumpIfNull ){
+        sqlite3ExprCodeIN(pParse, pExpr, dest, dest);
+      }else{
+        int destIfNull = sqlite3VdbeMakeLabel(pParse);
+        sqlite3ExprCodeIN(pParse, pExpr, dest, destIfNull);
+        sqlite3VdbeResolveLabel(v, destIfNull);
+      }
+      break;
+    }
+#endif
+    default: {
+    default_expr:
+      if( ExprAlwaysFalse(pExpr) ){
+        sqlite3VdbeGoto(v, dest);
+      }else if( ExprAlwaysTrue(pExpr) ){
+        /* no-op */
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pExpr, ®Free1);
+        sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0);
+        VdbeCoverage(v);
+        testcase( regFree1==0 );
+        testcase( jumpIfNull==0 );
+      }
+      break;
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+}
+
+/*
+** Like sqlite3ExprIfFalse() except that a copy is made of pExpr before
+** code generation, and that copy is deleted after code generation. This
+** ensures that the original pExpr is unchanged.
+*/
+SQLITE_PRIVATE void sqlite3ExprIfFalseDup(Parse *pParse, Expr *pExpr, int dest,int jumpIfNull){
+  sqlite3 *db = pParse->db;
+  Expr *pCopy = sqlite3ExprDup(db, pExpr, 0);
+  if( db->mallocFailed==0 ){
+    sqlite3ExprIfFalse(pParse, pCopy, dest, jumpIfNull);
+  }
+  sqlite3ExprDelete(db, pCopy);
+}
+
+/*
+** Expression pVar is guaranteed to be an SQL variable. pExpr may be any
+** type of expression.
+**
+** If pExpr is a simple SQL value - an integer, real, string, blob
+** or NULL value - then the VDBE currently being prepared is configured
+** to re-prepare each time a new value is bound to variable pVar.
+**
+** Additionally, if pExpr is a simple SQL value and the value is the
+** same as that currently bound to variable pVar, non-zero is returned.
+** Otherwise, if the values are not the same or if pExpr is not a simple
+** SQL value, zero is returned.
+**
+** If the SQLITE_EnableQPSG flag is set on the database connection, then
+** this routine always returns false.
+*/
+static SQLITE_NOINLINE int exprCompareVariable(
+  const Parse *pParse,
+  const Expr *pVar,
+  const Expr *pExpr
+){
+  int res = 2;
+  int iVar;
+  sqlite3_value *pL, *pR = 0;
+
+  if( pExpr->op==TK_VARIABLE && pVar->iColumn==pExpr->iColumn ){
+    return 0;
+  }
+  if( (pParse->db->flags & SQLITE_EnableQPSG)!=0 ) return 2;
+  sqlite3ValueFromExpr(pParse->db, pExpr, SQLITE_UTF8, SQLITE_AFF_BLOB, &pR);
+  if( pR ){
+    iVar = pVar->iColumn;
+    sqlite3VdbeSetVarmask(pParse->pVdbe, iVar);
+    pL = sqlite3VdbeGetBoundValue(pParse->pReprepare, iVar, SQLITE_AFF_BLOB);
+    if( pL ){
+      if( sqlite3_value_type(pL)==SQLITE_TEXT ){
+        sqlite3_value_text(pL); /* Make sure the encoding is UTF-8 */
+      }
+      res = sqlite3MemCompare(pL, pR, 0) ? 2 : 0;
+    }
+    sqlite3ValueFree(pR);
+    sqlite3ValueFree(pL);
+  }
+  return res;
+}
+
+/*
+** Do a deep comparison of two expression trees.  Return 0 if the two
+** expressions are completely identical.  Return 1 if they differ only
+** by a COLLATE operator at the top level.  Return 2 if there are differences
+** other than the top-level COLLATE operator.
+**
+** If any subelement of pB has Expr.iTable==(-1) then it is allowed
+** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
+**
+** The pA side might be using TK_REGISTER.  If that is the case and pB is
+** not using TK_REGISTER but is otherwise equivalent, then still return 0.
+**
+** Sometimes this routine will return 2 even if the two expressions
+** really are equivalent.  If we cannot prove that the expressions are
+** identical, we return 2 just to be safe.  So if this routine
+** returns 2, then you do not really know for certain if the two
+** expressions are the same.  But if you get a 0 or 1 return, then you
+** can be sure the expressions are the same.  In the places where
+** this routine is used, it does not hurt to get an extra 2 - that
+** just might result in some slightly slower code.  But returning
+** an incorrect 0 or 1 could lead to a malfunction.
+**
+** If pParse is not NULL and SQLITE_EnableQPSG is off then TK_VARIABLE
+** terms in pA with bindings in pParse->pReprepare can be matched against
+** literals in pB.  The pParse->pVdbe->expmask bitmask is updated for
+** each variable referenced.
+*/
+SQLITE_PRIVATE int sqlite3ExprCompare(
+  const Parse *pParse,
+  const Expr *pA,
+  const Expr *pB,
+  int iTab
+){
+  u32 combinedFlags;
+  if( pA==0 || pB==0 ){
+    return pB==pA ? 0 : 2;
+  }
+  if( pParse && pA->op==TK_VARIABLE ){
+    return exprCompareVariable(pParse, pA, pB);
+  }
+  combinedFlags = pA->flags | pB->flags;
+  if( combinedFlags & EP_IntValue ){
+    if( (pA->flags&pB->flags&EP_IntValue)!=0 && pA->u.iValue==pB->u.iValue ){
+      return 0;
+    }
+    return 2;
+  }
+  if( pA->op!=pB->op || pA->op==TK_RAISE ){
+    if( pA->op==TK_COLLATE && sqlite3ExprCompare(pParse, pA->pLeft,pB,iTab)<2 ){
+      return 1;
+    }
+    if( pB->op==TK_COLLATE && sqlite3ExprCompare(pParse, pA,pB->pLeft,iTab)<2 ){
+      return 1;
+    }
+    if( pA->op==TK_AGG_COLUMN && pB->op==TK_COLUMN
+     && pB->iTable<0 && pA->iTable==iTab
+    ){
+      /* fall through */
+    }else{
+      return 2;
+    }
+  }
+  assert( !ExprHasProperty(pA, EP_IntValue) );
+  assert( !ExprHasProperty(pB, EP_IntValue) );
+  if( pA->u.zToken ){
+    if( pA->op==TK_FUNCTION || pA->op==TK_AGG_FUNCTION ){
+      if( sqlite3StrICmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      assert( pA->op==pB->op );
+      if( ExprHasProperty(pA,EP_WinFunc)!=ExprHasProperty(pB,EP_WinFunc) ){
+        return 2;
+      }
+      if( ExprHasProperty(pA,EP_WinFunc) ){
+        if( sqlite3WindowCompare(pParse, pA->y.pWin, pB->y.pWin, 1)!=0 ){
+          return 2;
+        }
+      }
+#endif
+    }else if( pA->op==TK_NULL ){
+      return 0;
+    }else if( pA->op==TK_COLLATE ){
+      if( sqlite3_stricmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
+    }else
+    if( pB->u.zToken!=0
+     && pA->op!=TK_COLUMN
+     && pA->op!=TK_AGG_COLUMN
+     && strcmp(pA->u.zToken,pB->u.zToken)!=0
+    ){
+      return 2;
+    }
+  }
+  if( (pA->flags & (EP_Distinct|EP_Commuted))
+     != (pB->flags & (EP_Distinct|EP_Commuted)) ) return 2;
+  if( ALWAYS((combinedFlags & EP_TokenOnly)==0) ){
+    if( combinedFlags & EP_xIsSelect ) return 2;
+    if( (combinedFlags & EP_FixedCol)==0
+     && sqlite3ExprCompare(pParse, pA->pLeft, pB->pLeft, iTab) ) return 2;
+    if( sqlite3ExprCompare(pParse, pA->pRight, pB->pRight, iTab) ) return 2;
+    if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList, iTab) ) return 2;
+    if( pA->op!=TK_STRING
+     && pA->op!=TK_TRUEFALSE
+     && ALWAYS((combinedFlags & EP_Reduced)==0)
+    ){
+      if( pA->iColumn!=pB->iColumn ) return 2;
+      if( pA->op2!=pB->op2 && pA->op==TK_TRUTH ) return 2;
+      if( pA->op!=TK_IN && pA->iTable!=pB->iTable && pA->iTable!=iTab ){
+        return 2;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Compare two ExprList objects.  Return 0 if they are identical, 1
+** if they are certainly different, or 2 if it is not possible to
+** determine if they are identical or not.
+**
+** If any subelement of pB has Expr.iTable==(-1) then it is allowed
+** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
+**
+** This routine might return non-zero for equivalent ExprLists.  The
+** only consequence will be disabled optimizations.  But this routine
+** must never return 0 if the two ExprList objects are different, or
+** a malfunction will result.
+**
+** Two NULL pointers are considered to be the same.  But a NULL pointer
+** always differs from a non-NULL pointer.
+*/
+SQLITE_PRIVATE int sqlite3ExprListCompare(const ExprList *pA, const ExprList *pB, int iTab){
+  int i;
+  if( pA==0 && pB==0 ) return 0;
+  if( pA==0 || pB==0 ) return 1;
+  if( pA->nExpr!=pB->nExpr ) return 1;
+  for(i=0; i<pA->nExpr; i++){
+    int res;
+    Expr *pExprA = pA->a[i].pExpr;
+    Expr *pExprB = pB->a[i].pExpr;
+    if( pA->a[i].fg.sortFlags!=pB->a[i].fg.sortFlags ) return 1;
+    if( (res = sqlite3ExprCompare(0, pExprA, pExprB, iTab)) ) return res;
+  }
+  return 0;
+}
+
+/*
+** Like sqlite3ExprCompare() except COLLATE operators at the top-level
+** are ignored.
+*/
+SQLITE_PRIVATE int sqlite3ExprCompareSkip(Expr *pA,Expr *pB, int iTab){
+  return sqlite3ExprCompare(0,
+             sqlite3ExprSkipCollate(pA),
+             sqlite3ExprSkipCollate(pB),
+             iTab);
+}
+
+/*
+** Return non-zero if Expr p can only be true if pNN is not NULL.
+**
+** Or if seenNot is true, return non-zero if Expr p can only be
+** non-NULL if pNN is not NULL
+*/
+static int exprImpliesNotNull(
+  const Parse *pParse,/* Parsing context */
+  const Expr *p,      /* The expression to be checked */
+  const Expr *pNN,    /* The expression that is NOT NULL */
+  int iTab,           /* Table being evaluated */
+  int seenNot         /* Return true only if p can be any non-NULL value */
+){
+  assert( p );
+  assert( pNN );
+  if( sqlite3ExprCompare(pParse, p, pNN, iTab)==0 ){
+    return pNN->op!=TK_NULL;
+  }
+  switch( p->op ){
+    case TK_IN: {
+      if( seenNot && ExprHasProperty(p, EP_xIsSelect) ) return 0;
+      assert( ExprUseXSelect(p) || (p->x.pList!=0 && p->x.pList->nExpr>0) );
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, 1);
+    }
+    case TK_BETWEEN: {
+      ExprList *pList;
+      assert( ExprUseXList(p) );
+      pList = p->x.pList;
+      assert( pList!=0 );
+      assert( pList->nExpr==2 );
+      if( seenNot ) return 0;
+      if( exprImpliesNotNull(pParse, pList->a[0].pExpr, pNN, iTab, 1)
+       || exprImpliesNotNull(pParse, pList->a[1].pExpr, pNN, iTab, 1)
+      ){
+        return 1;
+      }
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, 1);
+    }
+    case TK_EQ:
+    case TK_NE:
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_PLUS:
+    case TK_MINUS:
+    case TK_BITOR:
+    case TK_LSHIFT:
+    case TK_RSHIFT:
+    case TK_CONCAT:
+      seenNot = 1;
+      /* no break */ deliberate_fall_through
+    case TK_STAR:
+    case TK_REM:
+    case TK_BITAND:
+    case TK_SLASH: {
+      if( exprImpliesNotNull(pParse, p->pRight, pNN, iTab, seenNot) ) return 1;
+      /* no break */ deliberate_fall_through
+    }
+    case TK_SPAN:
+    case TK_COLLATE:
+    case TK_UPLUS:
+    case TK_UMINUS: {
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, seenNot);
+    }
+    case TK_TRUTH: {
+      if( seenNot ) return 0;
+      if( p->op2!=TK_IS ) return 0;
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, 1);
+    }
+    case TK_BITNOT:
+    case TK_NOT: {
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, 1);
+    }
+  }
+  return 0;
+}
+
+/*
+** Return true if the boolean value of the expression is always either
+** FALSE or NULL.
+*/
+static int sqlite3ExprIsNotTrue(Expr *pExpr){
+  int v;
+  if( pExpr->op==TK_NULL ) return 1;
+  if( pExpr->op==TK_TRUEFALSE && sqlite3ExprTruthValue(pExpr)==0 ) return 1;
+  v = 1;
+  if( sqlite3ExprIsInteger(pExpr, &v, 0) && v==0 ) return 1;
+  return 0;
+}
+
+/*
+** Return true if the expression is one of the following:
+**
+**    CASE WHEN x THEN y END
+**    CASE WHEN x THEN y ELSE NULL END
+**    CASE WHEN x THEN y ELSE false END
+**    iif(x,y)
+**    iif(x,y,NULL)
+**    iif(x,y,false)
+*/
+static int sqlite3ExprIsIIF(sqlite3 *db, const Expr *pExpr){
+  ExprList *pList;
+  if( pExpr->op==TK_FUNCTION ){
+    const char *z = pExpr->u.zToken;
+    FuncDef *pDef;
+    if( (z[0]!='i' && z[0]!='I') ) return 0;
+    if( pExpr->x.pList==0 ) return 0;
+    pDef = sqlite3FindFunction(db, z, pExpr->x.pList->nExpr, ENC(db), 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+    if( pDef==0 ) return 0;
+#else
+    if( NEVER(pDef==0) ) return 0;
+#endif
+    if( (pDef->funcFlags & SQLITE_FUNC_INLINE)==0 ) return 0;
+    if( SQLITE_PTR_TO_INT(pDef->pUserData)!=INLINEFUNC_iif ) return 0;
+  }else if( pExpr->op==TK_CASE ){
+    if( pExpr->pLeft!=0 ) return 0;
+  }else{
+    return 0;
+  }
+  pList = pExpr->x.pList;
+  assert( pList!=0 );
+  if( pList->nExpr==2 ) return 1;
+  if( pList->nExpr==3 && sqlite3ExprIsNotTrue(pList->a[2].pExpr) ) return 1;
+  return 0;
+}
+
+/*
+** Return true if we can prove the pE2 will always be true if pE1 is
+** true.  Return false if we cannot complete the proof or if pE2 might
+** be false.  Examples:
+**
+**     pE1: x==5        pE2: x==5             Result: true
+**     pE1: x>0         pE2: x==5             Result: false
+**     pE1: x=21        pE2: x=21 OR y=43     Result: true
+**     pE1: x!=123      pE2: x IS NOT NULL    Result: true
+**     pE1: x!=?1       pE2: x IS NOT NULL    Result: true
+**     pE1: x IS NULL   pE2: x IS NOT NULL    Result: false
+**     pE1: x IS ?2     pE2: x IS NOT NULL    Result: false
+**     pE1: iif(x,y)    pE2: x                Result: true
+**     PE1: iif(x,y,0)  pE2: x                Result: true
+**
+** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has
+** Expr.iTable<0 then assume a table number given by iTab.
+**
+** If pParse is not NULL, then the values of bound variables in pE1 are
+** compared against literal values in pE2 and pParse->pVdbe->expmask is
+** modified to record which bound variables are referenced.  If pParse
+** is NULL, then false will be returned if pE1 contains any bound variables.
+**
+** When in doubt, return false.  Returning true might give a performance
+** improvement.  Returning false might cause a performance reduction, but
+** it will always give the correct answer and is hence always safe.
+*/
+SQLITE_PRIVATE int sqlite3ExprImpliesExpr(
+  const Parse *pParse,
+  const Expr *pE1,
+  const Expr *pE2,
+  int iTab
+){
+  if( sqlite3ExprCompare(pParse, pE1, pE2, iTab)==0 ){
+    return 1;
+  }
+  if( pE2->op==TK_OR
+   && (sqlite3ExprImpliesExpr(pParse, pE1, pE2->pLeft, iTab)
+             || sqlite3ExprImpliesExpr(pParse, pE1, pE2->pRight, iTab) )
+  ){
+    return 1;
+  }
+  if( pE2->op==TK_NOTNULL
+   && exprImpliesNotNull(pParse, pE1, pE2->pLeft, iTab, 0)
+  ){
+    return 1;
+  }
+  if( sqlite3ExprIsIIF(pParse->db, pE1) ){
+    return sqlite3ExprImpliesExpr(pParse,pE1->x.pList->a[0].pExpr,pE2,iTab);
+  }
+  return 0;
+}
+
+/* This is a helper function to impliesNotNullRow().  In this routine,
+** set pWalker->eCode to one only if *both* of the input expressions
+** separately have the implies-not-null-row property.
+*/
+static void bothImplyNotNullRow(Walker *pWalker, Expr *pE1, Expr *pE2){
+  if( pWalker->eCode==0 ){
+    sqlite3WalkExpr(pWalker, pE1);
+    if( pWalker->eCode ){
+      pWalker->eCode = 0;
+      sqlite3WalkExpr(pWalker, pE2);
+    }
+  }
+}
+
+/*
+** This is the Expr node callback for sqlite3ExprImpliesNonNullRow().
+** If the expression node requires that the table at pWalker->iCur
+** have one or more non-NULL column, then set pWalker->eCode to 1 and abort.
+**
+** pWalker->mWFlags is non-zero if this inquiry is being undertaking on
+** behalf of a RIGHT JOIN (or FULL JOIN).  That makes a difference when
+** evaluating terms in the ON clause of an inner join.
+**
+** This routine controls an optimization.  False positives (setting
+** pWalker->eCode to 1 when it should not be) are deadly, but false-negatives
+** (never setting pWalker->eCode) is a harmless missed optimization.
+*/
+static int impliesNotNullRow(Walker *pWalker, Expr *pExpr){
+  testcase( pExpr->op==TK_AGG_COLUMN );
+  testcase( pExpr->op==TK_AGG_FUNCTION );
+  if( ExprHasProperty(pExpr, EP_OuterON) ) return WRC_Prune;
+  if( ExprHasProperty(pExpr, EP_InnerON) && pWalker->mWFlags ){
+    /* If iCur is used in an inner-join ON clause to the left of a
+    ** RIGHT JOIN, that does *not* mean that the table must be non-null.
+    ** But it is difficult to check for that condition precisely.
+    ** To keep things simple, any use of iCur from any inner-join is
+    ** ignored while attempting to simplify a RIGHT JOIN. */
+    return WRC_Prune;
+  }
+  switch( pExpr->op ){
+    case TK_ISNOT:
+    case TK_ISNULL:
+    case TK_NOTNULL:
+    case TK_IS:
+    case TK_VECTOR:
+    case TK_FUNCTION:
+    case TK_TRUTH:
+    case TK_CASE:
+      testcase( pExpr->op==TK_ISNOT );
+      testcase( pExpr->op==TK_ISNULL );
+      testcase( pExpr->op==TK_NOTNULL );
+      testcase( pExpr->op==TK_IS );
+      testcase( pExpr->op==TK_VECTOR );
+      testcase( pExpr->op==TK_FUNCTION );
+      testcase( pExpr->op==TK_TRUTH );
+      testcase( pExpr->op==TK_CASE );
+      return WRC_Prune;
+
+    case TK_COLUMN:
+      if( pWalker->u.iCur==pExpr->iTable ){
+        pWalker->eCode = 1;
+        return WRC_Abort;
+      }
+      return WRC_Prune;
+
+    case TK_OR:
+    case TK_AND:
+      /* Both sides of an AND or OR must separately imply non-null-row.
+      ** Consider these cases:
+      **    1.  NOT (x AND y)
+      **    2.  x OR y
+      ** If only one of x or y is non-null-row, then the overall expression
+      ** can be true if the other arm is false (case 1) or true (case 2).
+      */
+      testcase( pExpr->op==TK_OR );
+      testcase( pExpr->op==TK_AND );
+      bothImplyNotNullRow(pWalker, pExpr->pLeft, pExpr->pRight);
+      return WRC_Prune;
+
+    case TK_IN:
+      /* Beware of "x NOT IN ()" and "x NOT IN (SELECT 1 WHERE false)",
+      ** both of which can be true.  But apart from these cases, if
+      ** the left-hand side of the IN is NULL then the IN itself will be
+      ** NULL. */
+      if( ExprUseXList(pExpr) && ALWAYS(pExpr->x.pList->nExpr>0) ){
+        sqlite3WalkExpr(pWalker, pExpr->pLeft);
+      }
+      return WRC_Prune;
+
+    case TK_BETWEEN:
+      /* In "x NOT BETWEEN y AND z" either x must be non-null-row or else
+      ** both y and z must be non-null row */
+      assert( ExprUseXList(pExpr) );
+      assert( pExpr->x.pList->nExpr==2 );
+      sqlite3WalkExpr(pWalker, pExpr->pLeft);
+      bothImplyNotNullRow(pWalker, pExpr->x.pList->a[0].pExpr,
+                                   pExpr->x.pList->a[1].pExpr);
+      return WRC_Prune;
+
+    /* Virtual tables are allowed to use constraints like x=NULL.  So
+    ** a term of the form x=y does not prove that y is not null if x
+    ** is the column of a virtual table */
+    case TK_EQ:
+    case TK_NE:
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE: {
+      Expr *pLeft = pExpr->pLeft;
+      Expr *pRight = pExpr->pRight;
+      testcase( pExpr->op==TK_EQ );
+      testcase( pExpr->op==TK_NE );
+      testcase( pExpr->op==TK_LT );
+      testcase( pExpr->op==TK_LE );
+      testcase( pExpr->op==TK_GT );
+      testcase( pExpr->op==TK_GE );
+      /* The y.pTab=0 assignment in wherecode.c always happens after the
+      ** impliesNotNullRow() test */
+      assert( pLeft->op!=TK_COLUMN || ExprUseYTab(pLeft) );
+      assert( pRight->op!=TK_COLUMN || ExprUseYTab(pRight) );
+      if( (pLeft->op==TK_COLUMN
+           && ALWAYS(pLeft->y.pTab!=0)
+           && IsVirtual(pLeft->y.pTab))
+       || (pRight->op==TK_COLUMN
+           && ALWAYS(pRight->y.pTab!=0)
+           && IsVirtual(pRight->y.pTab))
+      ){
+        return WRC_Prune;
+      }
+      /* no break */ deliberate_fall_through
+    }
+    default:
+      return WRC_Continue;
+  }
+}
+
+/*
+** Return true (non-zero) if expression p can only be true if at least
+** one column of table iTab is non-null.  In other words, return true
+** if expression p will always be NULL or false if every column of iTab
+** is NULL.
+**
+** False negatives are acceptable.  In other words, it is ok to return
+** zero even if expression p will never be true of every column of iTab
+** is NULL.  A false negative is merely a missed optimization opportunity.
+**
+** False positives are not allowed, however.  A false positive may result
+** in an incorrect answer.
+**
+** Terms of p that are marked with EP_OuterON (and hence that come from
+** the ON or USING clauses of OUTER JOINS) are excluded from the analysis.
+**
+** This routine is used to check if a LEFT JOIN can be converted into
+** an ordinary JOIN.  The p argument is the WHERE clause.  If the WHERE
+** clause requires that some column of the right table of the LEFT JOIN
+** be non-NULL, then the LEFT JOIN can be safely converted into an
+** ordinary join.
+*/
+SQLITE_PRIVATE int sqlite3ExprImpliesNonNullRow(Expr *p, int iTab, int isRJ){
+  Walker w;
+  p = sqlite3ExprSkipCollateAndLikely(p);
+  if( p==0 ) return 0;
+  if( p->op==TK_NOTNULL ){
+    p = p->pLeft;
+  }else{
+    while( p->op==TK_AND ){
+      if( sqlite3ExprImpliesNonNullRow(p->pLeft, iTab, isRJ) ) return 1;
+      p = p->pRight;
+    }
+  }
+  w.xExprCallback = impliesNotNullRow;
+  w.xSelectCallback = 0;
+  w.xSelectCallback2 = 0;
+  w.eCode = 0;
+  w.mWFlags = isRJ!=0;
+  w.u.iCur = iTab;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+/*
+** An instance of the following structure is used by the tree walker
+** to determine if an expression can be evaluated by reference to the
+** index only, without having to do a search for the corresponding
+** table entry.  The IdxCover.pIdx field is the index.  IdxCover.iCur
+** is the cursor for the table.
+*/
+struct IdxCover {
+  Index *pIdx;     /* The index to be tested for coverage */
+  int iCur;        /* Cursor number for the table corresponding to the index */
+};
+
+/*
+** Check to see if there are references to columns in table
+** pWalker->u.pIdxCover->iCur can be satisfied using the index
+** pWalker->u.pIdxCover->pIdx.
+*/
+static int exprIdxCover(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_COLUMN
+   && pExpr->iTable==pWalker->u.pIdxCover->iCur
+   && sqlite3TableColumnToIndex(pWalker->u.pIdxCover->pIdx, pExpr->iColumn)<0
+  ){
+    pWalker->eCode = 1;
+    return WRC_Abort;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Determine if an index pIdx on table with cursor iCur contains will
+** the expression pExpr.  Return true if the index does cover the
+** expression and false if the pExpr expression references table columns
+** that are not found in the index pIdx.
+**
+** An index covering an expression means that the expression can be
+** evaluated using only the index and without having to lookup the
+** corresponding table entry.
+*/
+SQLITE_PRIVATE int sqlite3ExprCoveredByIndex(
+  Expr *pExpr,        /* The index to be tested */
+  int iCur,           /* The cursor number for the corresponding table */
+  Index *pIdx         /* The index that might be used for coverage */
+){
+  Walker w;
+  struct IdxCover xcov;
+  memset(&w, 0, sizeof(w));
+  xcov.iCur = iCur;
+  xcov.pIdx = pIdx;
+  w.xExprCallback = exprIdxCover;
+  w.u.pIdxCover = &xcov;
+  sqlite3WalkExpr(&w, pExpr);
+  return !w.eCode;
+}
+
+
+/* Structure used to pass information throughout the Walker in order to
+** implement sqlite3ReferencesSrcList().
+*/
+struct RefSrcList {
+  sqlite3 *db;         /* Database connection used for sqlite3DbRealloc() */
+  SrcList *pRef;       /* Looking for references to these tables */
+  i64 nExclude;        /* Number of tables to exclude from the search */
+  int *aiExclude;      /* Cursor IDs for tables to exclude from the search */
+};
+
+/*
+** Walker SELECT callbacks for sqlite3ReferencesSrcList().
+**
+** When entering a new subquery on the pExpr argument, add all FROM clause
+** entries for that subquery to the exclude list.
+**
+** When leaving the subquery, remove those entries from the exclude list.
+*/
+static int selectRefEnter(Walker *pWalker, Select *pSelect){
+  struct RefSrcList *p = pWalker->u.pRefSrcList;
+  SrcList *pSrc = pSelect->pSrc;
+  i64 i, j;
+  int *piNew;
+  if( pSrc->nSrc==0 ) return WRC_Continue;
+  j = p->nExclude;
+  p->nExclude += pSrc->nSrc;
+  piNew = sqlite3DbRealloc(p->db, p->aiExclude, p->nExclude*sizeof(int));
+  if( piNew==0 ){
+    p->nExclude = 0;
+    return WRC_Abort;
+  }else{
+    p->aiExclude = piNew;
+  }
+  for(i=0; i<pSrc->nSrc; i++, j++){
+     p->aiExclude[j] = pSrc->a[i].iCursor;
+  }
+  return WRC_Continue;
+}
+static void selectRefLeave(Walker *pWalker, Select *pSelect){
+  struct RefSrcList *p = pWalker->u.pRefSrcList;
+  SrcList *pSrc = pSelect->pSrc;
+  if( p->nExclude ){
+    assert( p->nExclude>=pSrc->nSrc );
+    p->nExclude -= pSrc->nSrc;
+  }
+}
+
+/* This is the Walker EXPR callback for sqlite3ReferencesSrcList().
+**
+** Set the 0x01 bit of pWalker->eCode if there is a reference to any
+** of the tables shown in RefSrcList.pRef.
+**
+** Set the 0x02 bit of pWalker->eCode if there is a reference to a
+** table is in neither RefSrcList.pRef nor RefSrcList.aiExclude.
+*/
+static int exprRefToSrcList(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_COLUMN
+   || pExpr->op==TK_AGG_COLUMN
+  ){
+    int i;
+    struct RefSrcList *p = pWalker->u.pRefSrcList;
+    SrcList *pSrc = p->pRef;
+    int nSrc = pSrc ? pSrc->nSrc : 0;
+    for(i=0; i<nSrc; i++){
+      if( pExpr->iTable==pSrc->a[i].iCursor ){
+        pWalker->eCode |= 1;
+        return WRC_Continue;
+      }
+    }
+    for(i=0; i<p->nExclude && p->aiExclude[i]!=pExpr->iTable; i++){}
+    if( i>=p->nExclude ){
+      pWalker->eCode |= 2;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Check to see if pExpr references any tables in pSrcList.
+** Possible return values:
+**
+**    1         pExpr does references a table in pSrcList.
+**
+**    0         pExpr references some table that is not defined in either
+**              pSrcList or in subqueries of pExpr itself.
+**
+**   -1         pExpr only references no tables at all, or it only
+**              references tables defined in subqueries of pExpr itself.
+**
+** As currently used, pExpr is always an aggregate function call.  That
+** fact is exploited for efficiency.
+*/
+SQLITE_PRIVATE int sqlite3ReferencesSrcList(Parse *pParse, Expr *pExpr, SrcList *pSrcList){
+  Walker w;
+  struct RefSrcList x;
+  assert( pParse->db!=0 );
+  memset(&w, 0, sizeof(w));
+  memset(&x, 0, sizeof(x));
+  w.xExprCallback = exprRefToSrcList;
+  w.xSelectCallback = selectRefEnter;
+  w.xSelectCallback2 = selectRefLeave;
+  w.u.pRefSrcList = &x;
+  x.db = pParse->db;
+  x.pRef = pSrcList;
+  assert( pExpr->op==TK_AGG_FUNCTION );
+  assert( ExprUseXList(pExpr) );
+  sqlite3WalkExprList(&w, pExpr->x.pList);
+  if( pExpr->pLeft ){
+    assert( pExpr->pLeft->op==TK_ORDER );
+    assert( ExprUseXList(pExpr->pLeft) );
+    assert( pExpr->pLeft->x.pList!=0 );
+    sqlite3WalkExprList(&w, pExpr->pLeft->x.pList);
+  }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( ExprHasProperty(pExpr, EP_WinFunc) ){
+    sqlite3WalkExpr(&w, pExpr->y.pWin->pFilter);
+  }
+#endif
+  if( x.aiExclude ) sqlite3DbNNFreeNN(pParse->db, x.aiExclude);
+  if( w.eCode & 0x01 ){
+    return 1;
+  }else if( w.eCode ){
+    return 0;
+  }else{
+    return -1;
+  }
+}
+
+/*
+** This is a Walker expression node callback.
+**
+** For Expr nodes that contain pAggInfo pointers, make sure the AggInfo
+** object that is referenced does not refer directly to the Expr.  If
+** it does, make a copy.  This is done because the pExpr argument is
+** subject to change.
+**
+** The copy is scheduled for deletion using the sqlite3ExprDeferredDelete()
+** which builds on the sqlite3ParserAddCleanup() mechanism.
+*/
+static int agginfoPersistExprCb(Walker *pWalker, Expr *pExpr){
+  if( ALWAYS(!ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced))
+   && pExpr->pAggInfo!=0
+  ){
+    AggInfo *pAggInfo = pExpr->pAggInfo;
+    int iAgg = pExpr->iAgg;
+    Parse *pParse = pWalker->pParse;
+    sqlite3 *db = pParse->db;
+    assert( iAgg>=0 );
+    if( pExpr->op!=TK_AGG_FUNCTION ){
+      if( iAgg<pAggInfo->nColumn
+       && pAggInfo->aCol[iAgg].pCExpr==pExpr
+      ){
+        pExpr = sqlite3ExprDup(db, pExpr, 0);
+        if( pExpr && !sqlite3ExprDeferredDelete(pParse, pExpr) ){
+          pAggInfo->aCol[iAgg].pCExpr = pExpr;
+        }
+      }
+    }else{
+      assert( pExpr->op==TK_AGG_FUNCTION );
+      if( ALWAYS(iAgg<pAggInfo->nFunc)
+       && pAggInfo->aFunc[iAgg].pFExpr==pExpr
+      ){
+        pExpr = sqlite3ExprDup(db, pExpr, 0);
+        if( pExpr && !sqlite3ExprDeferredDelete(pParse, pExpr) ){
+          pAggInfo->aFunc[iAgg].pFExpr = pExpr;
+        }
+      }
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Initialize a Walker object so that will persist AggInfo entries referenced
+** by the tree that is walked.
+*/
+SQLITE_PRIVATE void sqlite3AggInfoPersistWalkerInit(Walker *pWalker, Parse *pParse){
+  memset(pWalker, 0, sizeof(*pWalker));
+  pWalker->pParse = pParse;
+  pWalker->xExprCallback = agginfoPersistExprCb;
+  pWalker->xSelectCallback = sqlite3SelectWalkNoop;
+}
+
+/*
+** Add a new element to the pAggInfo->aCol[] array.  Return the index of
+** the new element.  Return a negative number if malloc fails.
+*/
+static int addAggInfoColumn(sqlite3 *db, AggInfo *pInfo){
+  int i;
+  pInfo->aCol = sqlite3ArrayAllocate(
+       db,
+       pInfo->aCol,
+       sizeof(pInfo->aCol[0]),
+       &pInfo->nColumn,
+       &i
+  );
+  return i;
+}
+
+/*
+** Add a new element to the pAggInfo->aFunc[] array.  Return the index of
+** the new element.  Return a negative number if malloc fails.
+*/
+static int addAggInfoFunc(sqlite3 *db, AggInfo *pInfo){
+  int i;
+  pInfo->aFunc = sqlite3ArrayAllocate(
+       db,
+       pInfo->aFunc,
+       sizeof(pInfo->aFunc[0]),
+       &pInfo->nFunc,
+       &i
+  );
+  return i;
+}
+
+/*
+** Search the AggInfo object for an aCol[] entry that has iTable and iColumn.
+** Return the index in aCol[] of the entry that describes that column.
+**
+** If no prior entry is found, create a new one and return -1.  The
+** new column will have an index of pAggInfo->nColumn-1.
+*/
+static void findOrCreateAggInfoColumn(
+  Parse *pParse,       /* Parsing context */
+  AggInfo *pAggInfo,   /* The AggInfo object to search and/or modify */
+  Expr *pExpr          /* Expr describing the column to find or insert */
+){
+  struct AggInfo_col *pCol;
+  int k;
+
+  assert( pAggInfo->iFirstReg==0 );
+  pCol = pAggInfo->aCol;
+  for(k=0; k<pAggInfo->nColumn; k++, pCol++){
+    if( pCol->pCExpr==pExpr ) return;
+    if( pCol->iTable==pExpr->iTable
+     && pCol->iColumn==pExpr->iColumn
+     && pExpr->op!=TK_IF_NULL_ROW
+    ){
+      goto fix_up_expr;
+    }
+  }
+  k = addAggInfoColumn(pParse->db, pAggInfo);
+  if( k<0 ){
+    /* OOM on resize */
+    assert( pParse->db->mallocFailed );
+    return;
+  }
+  pCol = &pAggInfo->aCol[k];
+  assert( ExprUseYTab(pExpr) );
+  pCol->pTab = pExpr->y.pTab;
+  pCol->iTable = pExpr->iTable;
+  pCol->iColumn = pExpr->iColumn;
+  pCol->iSorterColumn = -1;
+  pCol->pCExpr = pExpr;
+  if( pAggInfo->pGroupBy && pExpr->op!=TK_IF_NULL_ROW ){
+    int j, n;
+    ExprList *pGB = pAggInfo->pGroupBy;
+    struct ExprList_item *pTerm = pGB->a;
+    n = pGB->nExpr;
+    for(j=0; j<n; j++, pTerm++){
+      Expr *pE = pTerm->pExpr;
+      if( pE->op==TK_COLUMN
+       && pE->iTable==pExpr->iTable
+       && pE->iColumn==pExpr->iColumn
+      ){
+        pCol->iSorterColumn = j;
+        break;
+      }
+    }
+  }
+  if( pCol->iSorterColumn<0 ){
+    pCol->iSorterColumn = pAggInfo->nSortingColumn++;
+  }
+fix_up_expr:
+  ExprSetVVAProperty(pExpr, EP_NoReduce);
+  assert( pExpr->pAggInfo==0 || pExpr->pAggInfo==pAggInfo );
+  pExpr->pAggInfo = pAggInfo;
+  if( pExpr->op==TK_COLUMN ){
+    pExpr->op = TK_AGG_COLUMN;
+  }
+  pExpr->iAgg = (i16)k;
+}
+
+/*
+** This is the xExprCallback for a tree walker.  It is used to
+** implement sqlite3ExprAnalyzeAggregates().  See sqlite3ExprAnalyzeAggregates
+** for additional information.
+*/
+static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
+  int i;
+  NameContext *pNC = pWalker->u.pNC;
+  Parse *pParse = pNC->pParse;
+  SrcList *pSrcList = pNC->pSrcList;
+  AggInfo *pAggInfo = pNC->uNC.pAggInfo;
+
+  assert( pNC->ncFlags & NC_UAggInfo );
+  assert( pAggInfo->iFirstReg==0 );
+  switch( pExpr->op ){
+    default: {
+      IndexedExpr *pIEpr;
+      Expr tmp;
+      assert( pParse->iSelfTab==0 );
+      if( (pNC->ncFlags & NC_InAggFunc)==0 ) break;
+      if( pParse->pIdxEpr==0 ) break;
+      for(pIEpr=pParse->pIdxEpr; pIEpr; pIEpr=pIEpr->pIENext){
+        int iDataCur = pIEpr->iDataCur;
+        if( iDataCur<0 ) continue;
+        if( sqlite3ExprCompare(0, pExpr, pIEpr->pExpr, iDataCur)==0 ) break;
+      }
+      if( pIEpr==0 ) break;
+      if( NEVER(!ExprUseYTab(pExpr)) ) break;
+      for(i=0; i<pSrcList->nSrc; i++){
+         if( pSrcList->a[0].iCursor==pIEpr->iDataCur ) break;
+      }
+      if( i>=pSrcList->nSrc ) break;
+      if( NEVER(pExpr->pAggInfo!=0) ) break; /* Resolved by outer context */
+      if( pParse->nErr ){ return WRC_Abort; }
+
+      /* If we reach this point, it means that expression pExpr can be
+      ** translated into a reference to an index column as described by
+      ** pIEpr.
+      */
+      memset(&tmp, 0, sizeof(tmp));
+      tmp.op = TK_AGG_COLUMN;
+      tmp.iTable = pIEpr->iIdxCur;
+      tmp.iColumn = pIEpr->iIdxCol;
+      findOrCreateAggInfoColumn(pParse, pAggInfo, &tmp);
+      if( pParse->nErr ){ return WRC_Abort; }
+      assert( pAggInfo->aCol!=0 );
+      assert( tmp.iAgg<pAggInfo->nColumn );
+      pAggInfo->aCol[tmp.iAgg].pCExpr = pExpr;
+      pExpr->pAggInfo = pAggInfo;
+      pExpr->iAgg = tmp.iAgg;
+      return WRC_Prune;
+    }
+    case TK_IF_NULL_ROW:
+    case TK_AGG_COLUMN:
+    case TK_COLUMN: {
+      testcase( pExpr->op==TK_AGG_COLUMN );
+      testcase( pExpr->op==TK_COLUMN );
+      testcase( pExpr->op==TK_IF_NULL_ROW );
+      /* Check to see if the column is in one of the tables in the FROM
+      ** clause of the aggregate query */
+      if( ALWAYS(pSrcList!=0) ){
+        SrcItem *pItem = pSrcList->a;
+        for(i=0; i<pSrcList->nSrc; i++, pItem++){
+          assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+          if( pExpr->iTable==pItem->iCursor ){
+            findOrCreateAggInfoColumn(pParse, pAggInfo, pExpr);
+            break;
+          } /* endif pExpr->iTable==pItem->iCursor */
+        } /* end loop over pSrcList */
+      }
+      return WRC_Continue;
+    }
+    case TK_AGG_FUNCTION: {
+      if( (pNC->ncFlags & NC_InAggFunc)==0
+       && pWalker->walkerDepth==pExpr->op2
+       && pExpr->pAggInfo==0
+      ){
+        /* Check to see if pExpr is a duplicate of another aggregate
+        ** function that is already in the pAggInfo structure
+        */
+        struct AggInfo_func *pItem = pAggInfo->aFunc;
+        for(i=0; i<pAggInfo->nFunc; i++, pItem++){
+          if( NEVER(pItem->pFExpr==pExpr) ) break;
+          if( sqlite3ExprCompare(0, pItem->pFExpr, pExpr, -1)==0 ){
+            break;
+          }
+        }
+        if( i>=pAggInfo->nFunc ){
+          /* pExpr is original.  Make a new entry in pAggInfo->aFunc[]
+          */
+          u8 enc = ENC(pParse->db);
+          i = addAggInfoFunc(pParse->db, pAggInfo);
+          if( i>=0 ){
+            int nArg;
+            assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+            pItem = &pAggInfo->aFunc[i];
+            pItem->pFExpr = pExpr;
+            assert( ExprUseUToken(pExpr) );
+            nArg = pExpr->x.pList ? pExpr->x.pList->nExpr : 0;
+            pItem->pFunc = sqlite3FindFunction(pParse->db,
+                                         pExpr->u.zToken, nArg, enc, 0);
+            assert( pItem->bOBUnique==0 );
+            if( pExpr->pLeft
+             && (pItem->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL)==0
+            ){
+              /* The NEEDCOLL test above causes any ORDER BY clause on
+              ** aggregate min() or max() to be ignored. */
+              ExprList *pOBList;
+              assert( nArg>0 );
+              assert( pExpr->pLeft->op==TK_ORDER );
+              assert( ExprUseXList(pExpr->pLeft) );
+              pItem->iOBTab = pParse->nTab++;
+              pOBList = pExpr->pLeft->x.pList;
+              assert( pOBList->nExpr>0 );
+              assert( pItem->bOBUnique==0 );
+              if( pOBList->nExpr==1
+               && nArg==1
+               && sqlite3ExprCompare(0,pOBList->a[0].pExpr,
+                               pExpr->x.pList->a[0].pExpr,0)==0
+              ){
+                pItem->bOBPayload = 0;
+                pItem->bOBUnique = ExprHasProperty(pExpr, EP_Distinct);
+              }else{
+                pItem->bOBPayload = 1;
+              }
+              pItem->bUseSubtype =
+                    (pItem->pFunc->funcFlags & SQLITE_SUBTYPE)!=0;
+            }else{
+              pItem->iOBTab = -1;
+            }
+            if( ExprHasProperty(pExpr, EP_Distinct) && !pItem->bOBUnique ){
+              pItem->iDistinct = pParse->nTab++;
+            }else{
+              pItem->iDistinct = -1;
+            }
+          }
+        }
+        /* Make pExpr point to the appropriate pAggInfo->aFunc[] entry
+        */
+        assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+        ExprSetVVAProperty(pExpr, EP_NoReduce);
+        pExpr->iAgg = (i16)i;
+        pExpr->pAggInfo = pAggInfo;
+        return WRC_Prune;
+      }else{
+        return WRC_Continue;
+      }
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Analyze the pExpr expression looking for aggregate functions and
+** for variables that need to be added to AggInfo object that pNC->pAggInfo
+** points to.  Additional entries are made on the AggInfo object as
+** necessary.
+**
+** This routine should only be called after the expression has been
+** analyzed by sqlite3ResolveExprNames().
+*/
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
+  Walker w;
+  w.xExprCallback = analyzeAggregate;
+  w.xSelectCallback = sqlite3WalkerDepthIncrease;
+  w.xSelectCallback2 = sqlite3WalkerDepthDecrease;
+  w.walkerDepth = 0;
+  w.u.pNC = pNC;
+  w.pParse = 0;
+  assert( pNC->pSrcList!=0 );
+  sqlite3WalkExpr(&w, pExpr);
+}
+
+/*
+** Call sqlite3ExprAnalyzeAggregates() for every expression in an
+** expression list.  Return the number of errors.
+**
+** If an error is found, the analysis is cut short.
+*/
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext *pNC, ExprList *pList){
+  struct ExprList_item *pItem;
+  int i;
+  if( pList ){
+    for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
+      sqlite3ExprAnalyzeAggregates(pNC, pItem->pExpr);
+    }
+  }
+}
+
+/*
+** Allocate a single new register for use to hold some intermediate result.
+*/
+SQLITE_PRIVATE int sqlite3GetTempReg(Parse *pParse){
+  if( pParse->nTempReg==0 ){
+    return ++pParse->nMem;
+  }
+  return pParse->aTempReg[--pParse->nTempReg];
+}
+
+/*
+** Deallocate a register, making available for reuse for some other
+** purpose.
+*/
+SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
+  if( iReg ){
+    sqlite3VdbeReleaseRegisters(pParse, iReg, 1, 0, 0);
+    if( pParse->nTempReg<ArraySize(pParse->aTempReg) ){
+      pParse->aTempReg[pParse->nTempReg++] = iReg;
+    }
+  }
+}
+
+/*
+** Allocate or deallocate a block of nReg consecutive registers.
+*/
+SQLITE_PRIVATE int sqlite3GetTempRange(Parse *pParse, int nReg){
+  int i, n;
+  if( nReg==1 ) return sqlite3GetTempReg(pParse);
+  i = pParse->iRangeReg;
+  n = pParse->nRangeReg;
+  if( nReg<=n ){
+    pParse->iRangeReg += nReg;
+    pParse->nRangeReg -= nReg;
+  }else{
+    i = pParse->nMem+1;
+    pParse->nMem += nReg;
+  }
+  return i;
+}
+SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse *pParse, int iReg, int nReg){
+  if( nReg==1 ){
+    sqlite3ReleaseTempReg(pParse, iReg);
+    return;
+  }
+  sqlite3VdbeReleaseRegisters(pParse, iReg, nReg, 0, 0);
+  if( nReg>pParse->nRangeReg ){
+    pParse->nRangeReg = nReg;
+    pParse->iRangeReg = iReg;
+  }
+}
+
+/*
+** Mark all temporary registers as being unavailable for reuse.
+**
+** Always invoke this procedure after coding a subroutine or co-routine
+** that might be invoked from other parts of the code, to ensure that
+** the sub/co-routine does not use registers in common with the code that
+** invokes the sub/co-routine.
+*/
+SQLITE_PRIVATE void sqlite3ClearTempRegCache(Parse *pParse){
+  pParse->nTempReg = 0;
+  pParse->nRangeReg = 0;
+}
+
+/*
+** Make sure sufficient registers have been allocated so that
+** iReg is a valid register number.
+*/
+SQLITE_PRIVATE void sqlite3TouchRegister(Parse *pParse, int iReg){
+  if( pParse->nMem<iReg ) pParse->nMem = iReg;
+}
+
+#if defined(SQLITE_ENABLE_STAT4) || defined(SQLITE_DEBUG)
+/*
+** Return the latest reusable register in the set of all registers.
+** The value returned is no less than iMin.  If any register iMin or
+** greater is in permanent use, then return one more than that last
+** permanent register.
+*/
+SQLITE_PRIVATE int sqlite3FirstAvailableRegister(Parse *pParse, int iMin){
+  const ExprList *pList = pParse->pConstExpr;
+  if( pList ){
+    int i;
+    for(i=0; i<pList->nExpr; i++){
+      if( pList->a[i].u.iConstExprReg>=iMin ){
+        iMin = pList->a[i].u.iConstExprReg + 1;
+      }
+    }
+  }
+  pParse->nTempReg = 0;
+  pParse->nRangeReg = 0;
+  return iMin;
+}
+#endif /* SQLITE_ENABLE_STAT4 || SQLITE_DEBUG */
+
+/*
+** Validate that no temporary register falls within the range of
+** iFirst..iLast, inclusive.  This routine is only call from within assert()
+** statements.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3NoTempsInRange(Parse *pParse, int iFirst, int iLast){
+  int i;
+  if( pParse->nRangeReg>0
+   && pParse->iRangeReg+pParse->nRangeReg > iFirst
+   && pParse->iRangeReg <= iLast
+  ){
+     return 0;
+  }
+  for(i=0; i<pParse->nTempReg; i++){
+    if( pParse->aTempReg[i]>=iFirst && pParse->aTempReg[i]<=iLast ){
+      return 0;
+    }
+  }
+  if( pParse->pConstExpr ){
+    ExprList *pList = pParse->pConstExpr;
+    for(i=0; i<pList->nExpr; i++){
+      int iReg = pList->a[i].u.iConstExprReg;
+      if( iReg==0 ) continue;
+      if( iReg>=iFirst && iReg<=iLast ) return 0;
+    }
+  }
+  return 1;
+}
+#endif /* SQLITE_DEBUG */
+
+/************** End of expr.c ************************************************/
+/************** Begin file alter.c *******************************************/
+/*
+** 2005 February 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that used to generate VDBE code
+** that implements the ALTER TABLE command.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** The code in this file only exists if we are not omitting the
+** ALTER TABLE logic from the build.
+*/
+#ifndef SQLITE_OMIT_ALTERTABLE
+
+/*
+** Parameter zName is the name of a table that is about to be altered
+** (either with ALTER TABLE ... RENAME TO or ALTER TABLE ... ADD COLUMN).
+** If the table is a system table, this function leaves an error message
+** in pParse->zErr (system tables may not be altered) and returns non-zero.
+**
+** Or, if zName is not a system table, zero is returned.
+*/
+static int isAlterableTable(Parse *pParse, Table *pTab){
+  if( 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7)
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+   || (pTab->tabFlags & TF_Eponymous)!=0
+   || ( (pTab->tabFlags & TF_Shadow)!=0
+        && sqlite3ReadOnlyShadowTables(pParse->db)
+   )
+#endif
+  ){
+    sqlite3ErrorMsg(pParse, "table %s may not be altered", pTab->zName);
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Generate code to verify that the schemas of database zDb and, if
+** bTemp is not true, database "temp", can still be parsed. This is
+** called at the end of the generation of an ALTER TABLE ... RENAME ...
+** statement to ensure that the operation has not rendered any schema
+** objects unusable.
+*/
+static void renameTestSchema(
+  Parse *pParse,                  /* Parse context */
+  const char *zDb,                /* Name of db to verify schema of */
+  int bTemp,                      /* True if this is the temp db */
+  const char *zWhen,              /* "when" part of error message */
+  int bNoDQS                      /* Do not allow DQS in the schema */
+){
+  pParse->colNamesSet = 1;
+  sqlite3NestedParse(pParse,
+      "SELECT 1 "
+      "FROM \"%w\"." LEGACY_SCHEMA_TABLE " "
+      "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+      " AND sql NOT LIKE 'create virtual%%'"
+      " AND sqlite_rename_test(%Q, sql, type, name, %d, %Q, %d)=NULL ",
+      zDb,
+      zDb, bTemp, zWhen, bNoDQS
+  );
+
+  if( bTemp==0 ){
+    sqlite3NestedParse(pParse,
+        "SELECT 1 "
+        "FROM temp." LEGACY_SCHEMA_TABLE " "
+        "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+        " AND sql NOT LIKE 'create virtual%%'"
+        " AND sqlite_rename_test(%Q, sql, type, name, 1, %Q, %d)=NULL ",
+        zDb, zWhen, bNoDQS
+    );
+  }
+}
+
+/*
+** Generate VM code to replace any double-quoted strings (but not double-quoted
+** identifiers) within the "sql" column of the sqlite_schema table in
+** database zDb with their single-quoted equivalents. If argument bTemp is
+** not true, similarly update all SQL statements in the sqlite_schema table
+** of the temp db.
+*/
+static void renameFixQuotes(Parse *pParse, const char *zDb, int bTemp){
+  sqlite3NestedParse(pParse,
+      "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE
+      " SET sql = sqlite_rename_quotefix(%Q, sql)"
+      "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+      " AND sql NOT LIKE 'create virtual%%'" , zDb, zDb
+  );
+  if( bTemp==0 ){
+    sqlite3NestedParse(pParse,
+      "UPDATE temp." LEGACY_SCHEMA_TABLE
+      " SET sql = sqlite_rename_quotefix('temp', sql)"
+      "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+      " AND sql NOT LIKE 'create virtual%%'"
+    );
+  }
+}
+
+/*
+** Generate code to reload the schema for database iDb. And, if iDb!=1, for
+** the temp database as well.
+*/
+static void renameReloadSchema(Parse *pParse, int iDb, u16 p5){
+  Vdbe *v = pParse->pVdbe;
+  if( v ){
+    sqlite3ChangeCookie(pParse, iDb);
+    sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, iDb, 0, p5);
+    if( iDb!=1 ) sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, 1, 0, p5);
+  }
+}
+
+/*
+** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy"
+** command.
+*/
+SQLITE_PRIVATE void sqlite3AlterRenameTable(
+  Parse *pParse,            /* Parser context. */
+  SrcList *pSrc,            /* The table to rename. */
+  Token *pName              /* The new table name. */
+){
+  int iDb;                  /* Database that contains the table */
+  char *zDb;                /* Name of database iDb */
+  Table *pTab;              /* Table being renamed */
+  char *zName = 0;          /* NULL-terminated version of pName */
+  sqlite3 *db = pParse->db; /* Database connection */
+  int nTabName;             /* Number of UTF-8 characters in zTabName */
+  const char *zTabName;     /* Original name of the table */
+  Vdbe *v;
+  VTable *pVTab = 0;        /* Non-zero if this is a v-tab with an xRename() */
+
+  if( NEVER(db->mallocFailed) ) goto exit_rename_table;
+  assert( pSrc->nSrc==1 );
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+
+  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
+  if( !pTab ) goto exit_rename_table;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  zDb = db->aDb[iDb].zDbSName;
+
+  /* Get a NULL terminated version of the new table name. */
+  zName = sqlite3NameFromToken(db, pName);
+  if( !zName ) goto exit_rename_table;
+
+  /* Check that a table or index named 'zName' does not already exist
+  ** in database iDb. If so, this is an error.
+  */
+  if( sqlite3FindTable(db, zName, zDb)
+   || sqlite3FindIndex(db, zName, zDb)
+   || sqlite3IsShadowTableOf(db, pTab, zName)
+  ){
+    sqlite3ErrorMsg(pParse,
+        "there is already another table or index with this name: %s", zName);
+    goto exit_rename_table;
+  }
+
+  /* Make sure it is not a system table being altered, or a reserved name
+  ** that the table is being renamed to.
+  */
+  if( SQLITE_OK!=isAlterableTable(pParse, pTab) ){
+    goto exit_rename_table;
+  }
+  if( SQLITE_OK!=sqlite3CheckObjectName(pParse,zName,"table",zName) ){
+    goto exit_rename_table;
+  }
+
+#ifndef SQLITE_OMIT_VIEW
+  if( IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "view %s may not be altered", pTab->zName);
+    goto exit_rename_table;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
+    goto exit_rename_table;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto exit_rename_table;
+  }
+  if( IsVirtual(pTab) ){
+    pVTab = sqlite3GetVTable(db, pTab);
+    if( pVTab->pVtab->pModule->xRename==0 ){
+      pVTab = 0;
+    }
+  }
+#endif
+
+  /* Begin a transaction for database iDb. Then modify the schema cookie
+  ** (since the ALTER TABLE modifies the schema). Call sqlite3MayAbort(),
+  ** as the scalar functions (e.g. sqlite_rename_table()) invoked by the
+  ** nested SQL may raise an exception.  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ){
+    goto exit_rename_table;
+  }
+  sqlite3MayAbort(pParse);
+
+  /* figure out how many UTF-8 characters are in zName */
+  zTabName = pTab->zName;
+  nTabName = sqlite3Utf8CharLen(zTabName, -1);
+
+  /* Rewrite all CREATE TABLE, INDEX, TRIGGER or VIEW statements in
+  ** the schema to use the new table name.  */
+  sqlite3NestedParse(pParse,
+      "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE " SET "
+      "sql = sqlite_rename_table(%Q, type, name, sql, %Q, %Q, %d) "
+      "WHERE (type!='index' OR tbl_name=%Q COLLATE nocase)"
+      "AND   name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+      , zDb, zDb, zTabName, zName, (iDb==1), zTabName
+  );
+
+  /* Update the tbl_name and name columns of the sqlite_schema table
+  ** as required.  */
+  sqlite3NestedParse(pParse,
+      "UPDATE %Q." LEGACY_SCHEMA_TABLE " SET "
+          "tbl_name = %Q, "
+          "name = CASE "
+            "WHEN type='table' THEN %Q "
+            "WHEN name LIKE 'sqliteX_autoindex%%' ESCAPE 'X' "
+            "     AND type='index' THEN "
+             "'sqlite_autoindex_' || %Q || substr(name,%d+18) "
+            "ELSE name END "
+      "WHERE tbl_name=%Q COLLATE nocase AND "
+          "(type='table' OR type='index' OR type='trigger');",
+      zDb,
+      zName, zName, zName,
+      nTabName, zTabName
+  );
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+  /* If the sqlite_sequence table exists in this database, then update
+  ** it with the new table name.
+  */
+  if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
+    sqlite3NestedParse(pParse,
+        "UPDATE \"%w\".sqlite_sequence set name = %Q WHERE name = %Q",
+        zDb, zName, pTab->zName);
+  }
+#endif
+
+  /* If the table being renamed is not itself part of the temp database,
+  ** edit view and trigger definitions within the temp database
+  ** as required.  */
+  if( iDb!=1 ){
+    sqlite3NestedParse(pParse,
+        "UPDATE sqlite_temp_schema SET "
+            "sql = sqlite_rename_table(%Q, type, name, sql, %Q, %Q, 1), "
+            "tbl_name = "
+              "CASE WHEN tbl_name=%Q COLLATE nocase AND "
+              "  sqlite_rename_test(%Q, sql, type, name, 1, 'after rename', 0) "
+              "THEN %Q ELSE tbl_name END "
+            "WHERE type IN ('view', 'trigger')"
+        , zDb, zTabName, zName, zTabName, zDb, zName);
+  }
+
+  /* If this is a virtual table, invoke the xRename() function if
+  ** one is defined. The xRename() callback will modify the names
+  ** of any resources used by the v-table implementation (including other
+  ** SQLite tables) that are identified by the name of the virtual table.
+  */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( pVTab ){
+    int i = ++pParse->nMem;
+    sqlite3VdbeLoadString(v, i, zName);
+    sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0,(const char*)pVTab, P4_VTAB);
+  }
+#endif
+
+  renameReloadSchema(pParse, iDb, INITFLAG_AlterRename);
+  renameTestSchema(pParse, zDb, iDb==1, "after rename", 0);
+
+exit_rename_table:
+  sqlite3SrcListDelete(db, pSrc);
+  sqlite3DbFree(db, zName);
+}
+
+/*
+** Write code that will raise an error if the table described by
+** zDb and zTab is not empty.
+*/
+static void sqlite3ErrorIfNotEmpty(
+  Parse *pParse,        /* Parsing context */
+  const char *zDb,      /* Schema holding the table */
+  const char *zTab,     /* Table to check for empty */
+  const char *zErr      /* Error message text */
+){
+  sqlite3NestedParse(pParse,
+     "SELECT raise(ABORT,%Q) FROM \"%w\".\"%w\"",
+     zErr, zDb, zTab
+  );
+}
+
+/*
+** This function is called after an "ALTER TABLE ... ADD" statement
+** has been parsed. Argument pColDef contains the text of the new
+** column definition.
+**
+** The Table structure pParse->pNewTable was extended to include
+** the new column during parsing.
+*/
+SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
+  Table *pNew;              /* Copy of pParse->pNewTable */
+  Table *pTab;              /* Table being altered */
+  int iDb;                  /* Database number */
+  const char *zDb;          /* Database name */
+  const char *zTab;         /* Table name */
+  char *zCol;               /* Null-terminated column definition */
+  Column *pCol;             /* The new column */
+  Expr *pDflt;              /* Default value for the new column */
+  sqlite3 *db;              /* The database connection; */
+  Vdbe *v;                  /* The prepared statement under construction */
+  int r1;                   /* Temporary registers */
+
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nErr ) return;
+  assert( db->mallocFailed==0 );
+  pNew = pParse->pNewTable;
+  assert( pNew );
+
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  iDb = sqlite3SchemaToIndex(db, pNew->pSchema);
+  zDb = db->aDb[iDb].zDbSName;
+  zTab = &pNew->zName[16];  /* Skip the "sqlite_altertab_" prefix on the name */
+  pCol = &pNew->aCol[pNew->nCol-1];
+  pDflt = sqlite3ColumnExpr(pNew, pCol);
+  pTab = sqlite3FindTable(db, zTab, zDb);
+  assert( pTab );
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
+    return;
+  }
+#endif
+
+
+  /* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
+  ** If there is a NOT NULL constraint, then the default value for the
+  ** column must not be NULL.
+  */
+  if( pCol->colFlags & COLFLAG_PRIMKEY ){
+    sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
+    return;
+  }
+  if( pNew->pIndex ){
+    sqlite3ErrorMsg(pParse,
+         "Cannot add a UNIQUE column");
+    return;
+  }
+  if( (pCol->colFlags & COLFLAG_GENERATED)==0 ){
+    /* If the default value for the new column was specified with a
+    ** literal NULL, then set pDflt to 0. This simplifies checking
+    ** for an SQL NULL default below.
+    */
+    assert( pDflt==0 || pDflt->op==TK_SPAN );
+    if( pDflt && pDflt->pLeft->op==TK_NULL ){
+      pDflt = 0;
+    }
+    assert( IsOrdinaryTable(pNew) );
+    if( (db->flags&SQLITE_ForeignKeys) && pNew->u.tab.pFKey && pDflt ){
+      sqlite3ErrorIfNotEmpty(pParse, zDb, zTab,
+          "Cannot add a REFERENCES column with non-NULL default value");
+    }
+    if( pCol->notNull && !pDflt ){
+      sqlite3ErrorIfNotEmpty(pParse, zDb, zTab,
+          "Cannot add a NOT NULL column with default value NULL");
+    }
+
+
+    /* Ensure the default expression is something that sqlite3ValueFromExpr()
+    ** can handle (i.e. not CURRENT_TIME etc.)
+    */
+    if( pDflt ){
+      sqlite3_value *pVal = 0;
+      int rc;
+      rc = sqlite3ValueFromExpr(db, pDflt, SQLITE_UTF8, SQLITE_AFF_BLOB, &pVal);
+      assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+      if( rc!=SQLITE_OK ){
+        assert( db->mallocFailed == 1 );
+        return;
+      }
+      if( !pVal ){
+        sqlite3ErrorIfNotEmpty(pParse, zDb, zTab,
+           "Cannot add a column with non-constant default");
+      }
+      sqlite3ValueFree(pVal);
+    }
+  }else if( pCol->colFlags & COLFLAG_STORED ){
+    sqlite3ErrorIfNotEmpty(pParse, zDb, zTab, "cannot add a STORED column");
+  }
+
+
+  /* Modify the CREATE TABLE statement. */
+  zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
+  if( zCol ){
+    char *zEnd = &zCol[pColDef->n-1];
+    while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
+      *zEnd-- = '\0';
+    }
+    /* substr() operations on characters, but addColOffset is in bytes. So we
+    ** have to use printf() to translate between these units: */
+    assert( IsOrdinaryTable(pTab) );
+    assert( IsOrdinaryTable(pNew) );
+    sqlite3NestedParse(pParse,
+        "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE " SET "
+          "sql = printf('%%.%ds, ',sql) || %Q"
+          " || substr(sql,1+length(printf('%%.%ds',sql))) "
+        "WHERE type = 'table' AND name = %Q",
+      zDb, pNew->u.tab.addColOffset, zCol, pNew->u.tab.addColOffset,
+      zTab
+    );
+    sqlite3DbFree(db, zCol);
+  }
+
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    /* Make sure the schema version is at least 3.  But do not upgrade
+    ** from less than 3 to 4, as that will corrupt any preexisting DESC
+    ** index.
+    */
+    r1 = sqlite3GetTempReg(pParse);
+    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, BTREE_FILE_FORMAT);
+    sqlite3VdbeUsesBtree(v, iDb);
+    sqlite3VdbeAddOp2(v, OP_AddImm, r1, -2);
+    sqlite3VdbeAddOp2(v, OP_IfPos, r1, sqlite3VdbeCurrentAddr(v)+2);
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, 3);
+    sqlite3ReleaseTempReg(pParse, r1);
+
+    /* Reload the table definition */
+    renameReloadSchema(pParse, iDb, INITFLAG_AlterAdd);
+
+    /* Verify that constraints are still satisfied */
+    if( pNew->pCheck!=0
+     || (pCol->notNull && (pCol->colFlags & COLFLAG_GENERATED)!=0)
+     || (pTab->tabFlags & TF_Strict)!=0
+    ){
+      sqlite3NestedParse(pParse,
+        "SELECT CASE WHEN quick_check GLOB 'CHECK*'"
+        " THEN raise(ABORT,'CHECK constraint failed')"
+        " WHEN quick_check GLOB 'non-* value in*'"
+        " THEN raise(ABORT,'type mismatch on DEFAULT')"
+        " ELSE raise(ABORT,'NOT NULL constraint failed')"
+        " END"
+        "  FROM pragma_quick_check(%Q,%Q)"
+        " WHERE quick_check GLOB 'CHECK*'"
+        " OR quick_check GLOB 'NULL*'"
+        " OR quick_check GLOB 'non-* value in*'",
+        zTab, zDb
+      );
+    }
+  }
+}
+
+/*
+** This function is called by the parser after the table-name in
+** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument
+** pSrc is the full-name of the table being altered.
+**
+** This routine makes a (partial) copy of the Table structure
+** for the table being altered and sets Parse.pNewTable to point
+** to it. Routines called by the parser as the column definition
+** is parsed (i.e. sqlite3AddColumn()) add the new Column data to
+** the copy. The copy of the Table structure is deleted by tokenize.c
+** after parsing is finished.
+**
+** Routine sqlite3AlterFinishAddColumn() will be called to complete
+** coding the "ALTER TABLE ... ADD" statement.
+*/
+SQLITE_PRIVATE void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
+  Table *pNew;
+  Table *pTab;
+  int iDb;
+  int i;
+  int nAlloc;
+  sqlite3 *db = pParse->db;
+
+  /* Look up the table being altered. */
+  assert( pParse->pNewTable==0 );
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  if( db->mallocFailed ) goto exit_begin_add_column;
+  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
+  if( !pTab ) goto exit_begin_add_column;
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
+    goto exit_begin_add_column;
+  }
+#endif
+
+  /* Make sure this is not an attempt to ALTER a view. */
+  if( IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
+    goto exit_begin_add_column;
+  }
+  if( SQLITE_OK!=isAlterableTable(pParse, pTab) ){
+    goto exit_begin_add_column;
+  }
+
+  sqlite3MayAbort(pParse);
+  assert( IsOrdinaryTable(pTab) );
+  assert( pTab->u.tab.addColOffset>0 );
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+
+  /* Put a copy of the Table struct in Parse.pNewTable for the
+  ** sqlite3AddColumn() function and friends to modify.  But modify
+  ** the name by adding an "sqlite_altertab_" prefix.  By adding this
+  ** prefix, we insure that the name will not collide with an existing
+  ** table because user table are not allowed to have the "sqlite_"
+  ** prefix on their name.
+  */
+  pNew = (Table*)sqlite3DbMallocZero(db, sizeof(Table));
+  if( !pNew ) goto exit_begin_add_column;
+  pParse->pNewTable = pNew;
+  pNew->nTabRef = 1;
+  pNew->nCol = pTab->nCol;
+  assert( pNew->nCol>0 );
+  nAlloc = (((pNew->nCol-1)/8)*8)+8;
+  assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
+  pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*nAlloc);
+  pNew->zName = sqlite3MPrintf(db, "sqlite_altertab_%s", pTab->zName);
+  if( !pNew->aCol || !pNew->zName ){
+    assert( db->mallocFailed );
+    goto exit_begin_add_column;
+  }
+  memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
+  for(i=0; i<pNew->nCol; i++){
+    Column *pCol = &pNew->aCol[i];
+    pCol->zCnName = sqlite3DbStrDup(db, pCol->zCnName);
+    pCol->hName = sqlite3StrIHash(pCol->zCnName);
+  }
+  assert( IsOrdinaryTable(pNew) );
+  pNew->u.tab.pDfltList = sqlite3ExprListDup(db, pTab->u.tab.pDfltList, 0);
+  pNew->pSchema = db->aDb[iDb].pSchema;
+  pNew->u.tab.addColOffset = pTab->u.tab.addColOffset;
+  assert( pNew->nTabRef==1 );
+
+exit_begin_add_column:
+  sqlite3SrcListDelete(db, pSrc);
+  return;
+}
+
+/*
+** Parameter pTab is the subject of an ALTER TABLE ... RENAME COLUMN
+** command. This function checks if the table is a view or virtual
+** table (columns of views or virtual tables may not be renamed). If so,
+** it loads an error message into pParse and returns non-zero.
+**
+** Or, if pTab is not a view or virtual table, zero is returned.
+*/
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+static int isRealTable(Parse *pParse, Table *pTab, int bDrop){
+  const char *zType = 0;
+#ifndef SQLITE_OMIT_VIEW
+  if( IsView(pTab) ){
+    zType = "view";
+  }
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    zType = "virtual table";
+  }
+#endif
+  if( zType ){
+    sqlite3ErrorMsg(pParse, "cannot %s %s \"%s\"",
+        (bDrop ? "drop column from" : "rename columns of"),
+        zType, pTab->zName
+    );
+    return 1;
+  }
+  return 0;
+}
+#else /* !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE) */
+# define isRealTable(x,y,z) (0)
+#endif
+
+/*
+** Handles the following parser reduction:
+**
+**  cmd ::= ALTER TABLE pSrc RENAME COLUMN pOld TO pNew
+*/
+SQLITE_PRIVATE void sqlite3AlterRenameColumn(
+  Parse *pParse,                  /* Parsing context */
+  SrcList *pSrc,                  /* Table being altered.  pSrc->nSrc==1 */
+  Token *pOld,                    /* Name of column being changed */
+  Token *pNew                     /* New column name */
+){
+  sqlite3 *db = pParse->db;       /* Database connection */
+  Table *pTab;                    /* Table being updated */
+  int iCol;                       /* Index of column being renamed */
+  char *zOld = 0;                 /* Old column name */
+  char *zNew = 0;                 /* New column name */
+  const char *zDb;                /* Name of schema containing the table */
+  int iSchema;                    /* Index of the schema */
+  int bQuote;                     /* True to quote the new name */
+
+  /* Locate the table to be altered */
+  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
+  if( !pTab ) goto exit_rename_column;
+
+  /* Cannot alter a system table */
+  if( SQLITE_OK!=isAlterableTable(pParse, pTab) ) goto exit_rename_column;
+  if( SQLITE_OK!=isRealTable(pParse, pTab, 0) ) goto exit_rename_column;
+
+  /* Which schema holds the table to be altered */
+  iSchema = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iSchema>=0 );
+  zDb = db->aDb[iSchema].zDbSName;
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
+    goto exit_rename_column;
+  }
+#endif
+
+  /* Make sure the old name really is a column name in the table to be
+  ** altered.  Set iCol to be the index of the column being renamed */
+  zOld = sqlite3NameFromToken(db, pOld);
+  if( !zOld ) goto exit_rename_column;
+  for(iCol=0; iCol<pTab->nCol; iCol++){
+    if( 0==sqlite3StrICmp(pTab->aCol[iCol].zCnName, zOld) ) break;
+  }
+  if( iCol==pTab->nCol ){
+    sqlite3ErrorMsg(pParse, "no such column: \"%T\"", pOld);
+    goto exit_rename_column;
+  }
+
+  /* Ensure the schema contains no double-quoted strings */
+  renameTestSchema(pParse, zDb, iSchema==1, "", 0);
+  renameFixQuotes(pParse, zDb, iSchema==1);
+
+  /* Do the rename operation using a recursive UPDATE statement that
+  ** uses the sqlite_rename_column() SQL function to compute the new
+  ** CREATE statement text for the sqlite_schema table.
+  */
+  sqlite3MayAbort(pParse);
+  zNew = sqlite3NameFromToken(db, pNew);
+  if( !zNew ) goto exit_rename_column;
+  assert( pNew->n>0 );
+  bQuote = sqlite3Isquote(pNew->z[0]);
+  sqlite3NestedParse(pParse,
+      "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE " SET "
+      "sql = sqlite_rename_column(sql, type, name, %Q, %Q, %d, %Q, %d, %d) "
+      "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X' "
+      " AND (type != 'index' OR tbl_name = %Q)",
+      zDb,
+      zDb, pTab->zName, iCol, zNew, bQuote, iSchema==1,
+      pTab->zName
+  );
+
+  sqlite3NestedParse(pParse,
+      "UPDATE temp." LEGACY_SCHEMA_TABLE " SET "
+      "sql = sqlite_rename_column(sql, type, name, %Q, %Q, %d, %Q, %d, 1) "
+      "WHERE type IN ('trigger', 'view')",
+      zDb, pTab->zName, iCol, zNew, bQuote
+  );
+
+  /* Drop and reload the database schema. */
+  renameReloadSchema(pParse, iSchema, INITFLAG_AlterRename);
+  renameTestSchema(pParse, zDb, iSchema==1, "after rename", 1);
+
+ exit_rename_column:
+  sqlite3SrcListDelete(db, pSrc);
+  sqlite3DbFree(db, zOld);
+  sqlite3DbFree(db, zNew);
+  return;
+}
+
+/*
+** Each RenameToken object maps an element of the parse tree into
+** the token that generated that element.  The parse tree element
+** might be one of:
+**
+**     *  A pointer to an Expr that represents an ID
+**     *  The name of a table column in Column.zName
+**
+** A list of RenameToken objects can be constructed during parsing.
+** Each new object is created by sqlite3RenameTokenMap().
+** As the parse tree is transformed, the sqlite3RenameTokenRemap()
+** routine is used to keep the mapping current.
+**
+** After the parse finishes, renameTokenFind() routine can be used
+** to look up the actual token value that created some element in
+** the parse tree.
+*/
+struct RenameToken {
+  const void *p;         /* Parse tree element created by token t */
+  Token t;               /* The token that created parse tree element p */
+  RenameToken *pNext;    /* Next is a list of all RenameToken objects */
+};
+
+/*
+** The context of an ALTER TABLE RENAME COLUMN operation that gets passed
+** down into the Walker.
+*/
+typedef struct RenameCtx RenameCtx;
+struct RenameCtx {
+  RenameToken *pList;             /* List of tokens to overwrite */
+  int nList;                      /* Number of tokens in pList */
+  int iCol;                       /* Index of column being renamed */
+  Table *pTab;                    /* Table being ALTERed */
+  const char *zOld;               /* Old column name */
+};
+
+#ifdef SQLITE_DEBUG
+/*
+** This function is only for debugging. It performs two tasks:
+**
+**   1. Checks that pointer pPtr does not already appear in the
+**      rename-token list.
+**
+**   2. Dereferences each pointer in the rename-token list.
+**
+** The second is most effective when debugging under valgrind or
+** address-sanitizer or similar. If any of these pointers no longer
+** point to valid objects, an exception is raised by the memory-checking
+** tool.
+**
+** The point of this is to prevent comparisons of invalid pointer values.
+** Even though this always seems to work, it is undefined according to the
+** C standard. Example of undefined comparison:
+**
+**     sqlite3_free(x);
+**     if( x==y ) ...
+**
+** Technically, as x no longer points into a valid object or to the byte
+** following a valid object, it may not be used in comparison operations.
+*/
+static void renameTokenCheckAll(Parse *pParse, const void *pPtr){
+  assert( pParse==pParse->db->pParse );
+  assert( pParse->db->mallocFailed==0 || pParse->nErr!=0 );
+  if( pParse->nErr==0 ){
+    const RenameToken *p;
+    u32 i = 1;
+    for(p=pParse->pRename; p; p=p->pNext){
+      if( p->p ){
+        assert( p->p!=pPtr );
+        i += *(u8*)(p->p) | 1;
+      }
+    }
+    assert( i>0 );
+  }
+}
+#else
+# define renameTokenCheckAll(x,y)
+#endif
+
+/*
+** Remember that the parser tree element pPtr was created using
+** the token pToken.
+**
+** In other words, construct a new RenameToken object and add it
+** to the list of RenameToken objects currently being built up
+** in pParse->pRename.
+**
+** The pPtr argument is returned so that this routine can be used
+** with tail recursion in tokenExpr() routine, for a small performance
+** improvement.
+*/
+SQLITE_PRIVATE const void *sqlite3RenameTokenMap(
+  Parse *pParse,
+  const void *pPtr,
+  const Token *pToken
+){
+  RenameToken *pNew;
+  assert( pPtr || pParse->db->mallocFailed );
+  renameTokenCheckAll(pParse, pPtr);
+  if( ALWAYS(pParse->eParseMode!=PARSE_MODE_UNMAP) ){
+    pNew = sqlite3DbMallocZero(pParse->db, sizeof(RenameToken));
+    if( pNew ){
+      pNew->p = pPtr;
+      pNew->t = *pToken;
+      pNew->pNext = pParse->pRename;
+      pParse->pRename = pNew;
+    }
+  }
+
+  return pPtr;
+}
+
+/*
+** It is assumed that there is already a RenameToken object associated
+** with parse tree element pFrom. This function remaps the associated token
+** to parse tree element pTo.
+*/
+SQLITE_PRIVATE void sqlite3RenameTokenRemap(Parse *pParse, const void *pTo, const void *pFrom){
+  RenameToken *p;
+  renameTokenCheckAll(pParse, pTo);
+  for(p=pParse->pRename; p; p=p->pNext){
+    if( p->p==pFrom ){
+      p->p = pTo;
+      break;
+    }
+  }
+}
+
+/*
+** Walker callback used by sqlite3RenameExprUnmap().
+*/
+static int renameUnmapExprCb(Walker *pWalker, Expr *pExpr){
+  Parse *pParse = pWalker->pParse;
+  sqlite3RenameTokenRemap(pParse, 0, (const void*)pExpr);
+  if( ExprUseYTab(pExpr) ){
+    sqlite3RenameTokenRemap(pParse, 0, (const void*)&pExpr->y.pTab);
+  }
+  return WRC_Continue;
+}
+
+/*
+** Iterate through the Select objects that are part of WITH clauses attached
+** to select statement pSelect.
+*/
+static void renameWalkWith(Walker *pWalker, Select *pSelect){
+  With *pWith = pSelect->pWith;
+  if( pWith ){
+    Parse *pParse = pWalker->pParse;
+    int i;
+    With *pCopy = 0;
+    assert( pWith->nCte>0 );
+    if( (pWith->a[0].pSelect->selFlags & SF_Expanded)==0 ){
+      /* Push a copy of the With object onto the with-stack. We use a copy
+      ** here as the original will be expanded and resolved (flags SF_Expanded
+      ** and SF_Resolved) below. And the parser code that uses the with-stack
+      ** fails if the Select objects on it have already been expanded and
+      ** resolved.  */
+      pCopy = sqlite3WithDup(pParse->db, pWith);
+      pCopy = sqlite3WithPush(pParse, pCopy, 1);
+    }
+    for(i=0; i<pWith->nCte; i++){
+      Select *p = pWith->a[i].pSelect;
+      NameContext sNC;
+      memset(&sNC, 0, sizeof(sNC));
+      sNC.pParse = pParse;
+      if( pCopy ) sqlite3SelectPrep(sNC.pParse, p, &sNC);
+      if( sNC.pParse->db->mallocFailed ) return;
+      sqlite3WalkSelect(pWalker, p);
+      sqlite3RenameExprlistUnmap(pParse, pWith->a[i].pCols);
+    }
+    if( pCopy && pParse->pWith==pCopy ){
+      pParse->pWith = pCopy->pOuter;
+    }
+  }
+}
+
+/*
+** Unmap all tokens in the IdList object passed as the second argument.
+*/
+static void unmapColumnIdlistNames(
+  Parse *pParse,
+  const IdList *pIdList
+){
+  int ii;
+  assert( pIdList!=0 );
+  for(ii=0; ii<pIdList->nId; ii++){
+    sqlite3RenameTokenRemap(pParse, 0, (const void*)pIdList->a[ii].zName);
+  }
+}
+
+/*
+** Walker callback used by sqlite3RenameExprUnmap().
+*/
+static int renameUnmapSelectCb(Walker *pWalker, Select *p){
+  Parse *pParse = pWalker->pParse;
+  int i;
+  if( pParse->nErr ) return WRC_Abort;
+  testcase( p->selFlags & SF_View );
+  testcase( p->selFlags & SF_CopyCte );
+  if( p->selFlags & (SF_View|SF_CopyCte) ){
+    return WRC_Prune;
+  }
+  if( ALWAYS(p->pEList) ){
+    ExprList *pList = p->pEList;
+    for(i=0; i<pList->nExpr; i++){
+      if( pList->a[i].zEName && pList->a[i].fg.eEName==ENAME_NAME ){
+        sqlite3RenameTokenRemap(pParse, 0, (void*)pList->a[i].zEName);
+      }
+    }
+  }
+  if( ALWAYS(p->pSrc) ){  /* Every Select as a SrcList, even if it is empty */
+    SrcList *pSrc = p->pSrc;
+    for(i=0; i<pSrc->nSrc; i++){
+      sqlite3RenameTokenRemap(pParse, 0, (void*)pSrc->a[i].zName);
+      if( pSrc->a[i].fg.isUsing==0 ){
+        sqlite3WalkExpr(pWalker, pSrc->a[i].u3.pOn);
+      }else{
+        unmapColumnIdlistNames(pParse, pSrc->a[i].u3.pUsing);
+      }
+    }
+  }
+
+  renameWalkWith(pWalker, p);
+  return WRC_Continue;
+}
+
+/*
+** Remove all nodes that are part of expression pExpr from the rename list.
+*/
+SQLITE_PRIVATE void sqlite3RenameExprUnmap(Parse *pParse, Expr *pExpr){
+  u8 eMode = pParse->eParseMode;
+  Walker sWalker;
+  memset(&sWalker, 0, sizeof(Walker));
+  sWalker.pParse = pParse;
+  sWalker.xExprCallback = renameUnmapExprCb;
+  sWalker.xSelectCallback = renameUnmapSelectCb;
+  pParse->eParseMode = PARSE_MODE_UNMAP;
+  sqlite3WalkExpr(&sWalker, pExpr);
+  pParse->eParseMode = eMode;
+}
+
+/*
+** Remove all nodes that are part of expression-list pEList from the
+** rename list.
+*/
+SQLITE_PRIVATE void sqlite3RenameExprlistUnmap(Parse *pParse, ExprList *pEList){
+  if( pEList ){
+    int i;
+    Walker sWalker;
+    memset(&sWalker, 0, sizeof(Walker));
+    sWalker.pParse = pParse;
+    sWalker.xExprCallback = renameUnmapExprCb;
+    sqlite3WalkExprList(&sWalker, pEList);
+    for(i=0; i<pEList->nExpr; i++){
+      if( ALWAYS(pEList->a[i].fg.eEName==ENAME_NAME) ){
+        sqlite3RenameTokenRemap(pParse, 0, (void*)pEList->a[i].zEName);
+      }
+    }
+  }
+}
+
+/*
+** Free the list of RenameToken objects given in the second argument
+*/
+static void renameTokenFree(sqlite3 *db, RenameToken *pToken){
+  RenameToken *pNext;
+  RenameToken *p;
+  for(p=pToken; p; p=pNext){
+    pNext = p->pNext;
+    sqlite3DbFree(db, p);
+  }
+}
+
+/*
+** Search the Parse object passed as the first argument for a RenameToken
+** object associated with parse tree element pPtr. If found, return a pointer
+** to it. Otherwise, return NULL.
+**
+** If the second argument passed to this function is not NULL and a matching
+** RenameToken object is found, remove it from the Parse object and add it to
+** the list maintained by the RenameCtx object.
+*/
+static RenameToken *renameTokenFind(
+  Parse *pParse,
+  struct RenameCtx *pCtx,
+  const void *pPtr
+){
+  RenameToken **pp;
+  if( NEVER(pPtr==0) ){
+    return 0;
+  }
+  for(pp=&pParse->pRename; (*pp); pp=&(*pp)->pNext){
+    if( (*pp)->p==pPtr ){
+      RenameToken *pToken = *pp;
+      if( pCtx ){
+        *pp = pToken->pNext;
+        pToken->pNext = pCtx->pList;
+        pCtx->pList = pToken;
+        pCtx->nList++;
+      }
+      return pToken;
+    }
+  }
+  return 0;
+}
+
+/*
+** This is a Walker select callback. It does nothing. It is only required
+** because without a dummy callback, sqlite3WalkExpr() and similar do not
+** descend into sub-select statements.
+*/
+static int renameColumnSelectCb(Walker *pWalker, Select *p){
+  if( p->selFlags & (SF_View|SF_CopyCte) ){
+    testcase( p->selFlags & SF_View );
+    testcase( p->selFlags & SF_CopyCte );
+    return WRC_Prune;
+  }
+  renameWalkWith(pWalker, p);
+  return WRC_Continue;
+}
+
+/*
+** This is a Walker expression callback.
+**
+** For every TK_COLUMN node in the expression tree, search to see
+** if the column being references is the column being renamed by an
+** ALTER TABLE statement.  If it is, then attach its associated
+** RenameToken object to the list of RenameToken objects being
+** constructed in RenameCtx object at pWalker->u.pRename.
+*/
+static int renameColumnExprCb(Walker *pWalker, Expr *pExpr){
+  RenameCtx *p = pWalker->u.pRename;
+  if( pExpr->op==TK_TRIGGER
+   && pExpr->iColumn==p->iCol
+   && pWalker->pParse->pTriggerTab==p->pTab
+  ){
+    renameTokenFind(pWalker->pParse, p, (void*)pExpr);
+  }else if( pExpr->op==TK_COLUMN
+   && pExpr->iColumn==p->iCol
+   && ALWAYS(ExprUseYTab(pExpr))
+   && p->pTab==pExpr->y.pTab
+  ){
+    renameTokenFind(pWalker->pParse, p, (void*)pExpr);
+  }
+  return WRC_Continue;
+}
+
+/*
+** The RenameCtx contains a list of tokens that reference a column that
+** is being renamed by an ALTER TABLE statement.  Return the "last"
+** RenameToken in the RenameCtx and remove that RenameToken from the
+** RenameContext.  "Last" means the last RenameToken encountered when
+** the input SQL is parsed from left to right.  Repeated calls to this routine
+** return all column name tokens in the order that they are encountered
+** in the SQL statement.
+*/
+static RenameToken *renameColumnTokenNext(RenameCtx *pCtx){
+  RenameToken *pBest = pCtx->pList;
+  RenameToken *pToken;
+  RenameToken **pp;
+
+  for(pToken=pBest->pNext; pToken; pToken=pToken->pNext){
+    if( pToken->t.z>pBest->t.z ) pBest = pToken;
+  }
+  for(pp=&pCtx->pList; *pp!=pBest; pp=&(*pp)->pNext);
+  *pp = pBest->pNext;
+
+  return pBest;
+}
+
+/*
+** An error occurred while parsing or otherwise processing a database
+** object (either pParse->pNewTable, pNewIndex or pNewTrigger) as part of an
+** ALTER TABLE RENAME COLUMN program. The error message emitted by the
+** sub-routine is currently stored in pParse->zErrMsg. This function
+** adds context to the error message and then stores it in pCtx.
+*/
+static void renameColumnParseError(
+  sqlite3_context *pCtx,
+  const char *zWhen,
+  sqlite3_value *pType,
+  sqlite3_value *pObject,
+  Parse *pParse
+){
+  const char *zT = (const char*)sqlite3_value_text(pType);
+  const char *zN = (const char*)sqlite3_value_text(pObject);
+  char *zErr;
+
+  zErr = sqlite3MPrintf(pParse->db, "error in %s %s%s%s: %s",
+      zT, zN, (zWhen[0] ? " " : ""), zWhen,
+      pParse->zErrMsg
+  );
+  sqlite3_result_error(pCtx, zErr, -1);
+  sqlite3DbFree(pParse->db, zErr);
+}
+
+/*
+** For each name in the the expression-list pEList (i.e. each
+** pEList->a[i].zName) that matches the string in zOld, extract the
+** corresponding rename-token from Parse object pParse and add it
+** to the RenameCtx pCtx.
+*/
+static void renameColumnElistNames(
+  Parse *pParse,
+  RenameCtx *pCtx,
+  const ExprList *pEList,
+  const char *zOld
+){
+  if( pEList ){
+    int i;
+    for(i=0; i<pEList->nExpr; i++){
+      const char *zName = pEList->a[i].zEName;
+      if( ALWAYS(pEList->a[i].fg.eEName==ENAME_NAME)
+       && ALWAYS(zName!=0)
+       && 0==sqlite3_stricmp(zName, zOld)
+      ){
+        renameTokenFind(pParse, pCtx, (const void*)zName);
+      }
+    }
+  }
+}
+
+/*
+** For each name in the the id-list pIdList (i.e. each pIdList->a[i].zName)
+** that matches the string in zOld, extract the corresponding rename-token
+** from Parse object pParse and add it to the RenameCtx pCtx.
+*/
+static void renameColumnIdlistNames(
+  Parse *pParse,
+  RenameCtx *pCtx,
+  const IdList *pIdList,
+  const char *zOld
+){
+  if( pIdList ){
+    int i;
+    for(i=0; i<pIdList->nId; i++){
+      const char *zName = pIdList->a[i].zName;
+      if( 0==sqlite3_stricmp(zName, zOld) ){
+        renameTokenFind(pParse, pCtx, (const void*)zName);
+      }
+    }
+  }
+}
+
+
+/*
+** Parse the SQL statement zSql using Parse object (*p). The Parse object
+** is initialized by this function before it is used.
+*/
+static int renameParseSql(
+  Parse *p,                       /* Memory to use for Parse object */
+  const char *zDb,                /* Name of schema SQL belongs to */
+  sqlite3 *db,                    /* Database handle */
+  const char *zSql,               /* SQL to parse */
+  int bTemp                       /* True if SQL is from temp schema */
+){
+  int rc;
+
+  sqlite3ParseObjectInit(p, db);
+  if( zSql==0 ){
+    return SQLITE_NOMEM;
+  }
+  if( sqlite3StrNICmp(zSql,"CREATE ",7)!=0 ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  db->init.iDb = bTemp ? 1 : sqlite3FindDbName(db, zDb);
+  p->eParseMode = PARSE_MODE_RENAME;
+  p->db = db;
+  p->nQueryLoop = 1;
+  rc = sqlite3RunParser(p, zSql);
+  if( db->mallocFailed ) rc = SQLITE_NOMEM;
+  if( rc==SQLITE_OK
+   && NEVER(p->pNewTable==0 && p->pNewIndex==0 && p->pNewTrigger==0)
+  ){
+    rc = SQLITE_CORRUPT_BKPT;
+  }
+
+#ifdef SQLITE_DEBUG
+  /* Ensure that all mappings in the Parse.pRename list really do map to
+  ** a part of the input string.  */
+  if( rc==SQLITE_OK ){
+    int nSql = sqlite3Strlen30(zSql);
+    RenameToken *pToken;
+    for(pToken=p->pRename; pToken; pToken=pToken->pNext){
+      assert( pToken->t.z>=zSql && &pToken->t.z[pToken->t.n]<=&zSql[nSql] );
+    }
+  }
+#endif
+
+  db->init.iDb = 0;
+  return rc;
+}
+
+/*
+** This function edits SQL statement zSql, replacing each token identified
+** by the linked list pRename with the text of zNew. If argument bQuote is
+** true, then zNew is always quoted first. If no error occurs, the result
+** is loaded into context object pCtx as the result.
+**
+** Or, if an error occurs (i.e. an OOM condition), an error is left in
+** pCtx and an SQLite error code returned.
+*/
+static int renameEditSql(
+  sqlite3_context *pCtx,          /* Return result here */
+  RenameCtx *pRename,             /* Rename context */
+  const char *zSql,               /* SQL statement to edit */
+  const char *zNew,               /* New token text */
+  int bQuote                      /* True to always quote token */
+){
+  i64 nNew = sqlite3Strlen30(zNew);
+  i64 nSql = sqlite3Strlen30(zSql);
+  sqlite3 *db = sqlite3_context_db_handle(pCtx);
+  int rc = SQLITE_OK;
+  char *zQuot = 0;
+  char *zOut;
+  i64 nQuot = 0;
+  char *zBuf1 = 0;
+  char *zBuf2 = 0;
+
+  if( zNew ){
+    /* Set zQuot to point to a buffer containing a quoted copy of the
+    ** identifier zNew. If the corresponding identifier in the original
+    ** ALTER TABLE statement was quoted (bQuote==1), then set zNew to
+    ** point to zQuot so that all substitutions are made using the
+    ** quoted version of the new column name.  */
+    zQuot = sqlite3MPrintf(db, "\"%w\" ", zNew);
+    if( zQuot==0 ){
+      return SQLITE_NOMEM;
+    }else{
+      nQuot = sqlite3Strlen30(zQuot)-1;
+    }
+
+    assert( nQuot>=nNew );
+    zOut = sqlite3DbMallocZero(db, nSql + pRename->nList*nQuot + 1);
+  }else{
+    zOut = (char*)sqlite3DbMallocZero(db, (nSql*2+1) * 3);
+    if( zOut ){
+      zBuf1 = &zOut[nSql*2+1];
+      zBuf2 = &zOut[nSql*4+2];
+    }
+  }
+
+  /* At this point pRename->pList contains a list of RenameToken objects
+  ** corresponding to all tokens in the input SQL that must be replaced
+  ** with the new column name, or with single-quoted versions of themselves.
+  ** All that remains is to construct and return the edited SQL string. */
+  if( zOut ){
+    int nOut = nSql;
+    memcpy(zOut, zSql, nSql);
+    while( pRename->pList ){
+      int iOff;                   /* Offset of token to replace in zOut */
+      u32 nReplace;
+      const char *zReplace;
+      RenameToken *pBest = renameColumnTokenNext(pRename);
+
+      if( zNew ){
+        if( bQuote==0 && sqlite3IsIdChar(*pBest->t.z) ){
+          nReplace = nNew;
+          zReplace = zNew;
+        }else{
+          nReplace = nQuot;
+          zReplace = zQuot;
+          if( pBest->t.z[pBest->t.n]=='"' ) nReplace++;
+        }
+      }else{
+        /* Dequote the double-quoted token. Then requote it again, this time
+        ** using single quotes. If the character immediately following the
+        ** original token within the input SQL was a single quote ('), then
+        ** add another space after the new, single-quoted version of the
+        ** token. This is so that (SELECT "string"'alias') maps to
+        ** (SELECT 'string' 'alias'), and not (SELECT 'string''alias').  */
+        memcpy(zBuf1, pBest->t.z, pBest->t.n);
+        zBuf1[pBest->t.n] = 0;
+        sqlite3Dequote(zBuf1);
+        sqlite3_snprintf(nSql*2, zBuf2, "%Q%s", zBuf1,
+            pBest->t.z[pBest->t.n]=='\'' ? " " : ""
+        );
+        zReplace = zBuf2;
+        nReplace = sqlite3Strlen30(zReplace);
+      }
+
+      iOff = pBest->t.z - zSql;
+      if( pBest->t.n!=nReplace ){
+        memmove(&zOut[iOff + nReplace], &zOut[iOff + pBest->t.n],
+            nOut - (iOff + pBest->t.n)
+        );
+        nOut += nReplace - pBest->t.n;
+        zOut[nOut] = '\0';
+      }
+      memcpy(&zOut[iOff], zReplace, nReplace);
+      sqlite3DbFree(db, pBest);
+    }
+
+    sqlite3_result_text(pCtx, zOut, -1, SQLITE_TRANSIENT);
+    sqlite3DbFree(db, zOut);
+  }else{
+    rc = SQLITE_NOMEM;
+  }
+
+  sqlite3_free(zQuot);
+  return rc;
+}
+
+/*
+** Set all pEList->a[].fg.eEName fields in the expression-list to val.
+*/
+static void renameSetENames(ExprList *pEList, int val){
+  if( pEList ){
+    int i;
+    for(i=0; i<pEList->nExpr; i++){
+      assert( val==ENAME_NAME || pEList->a[i].fg.eEName==ENAME_NAME );
+      pEList->a[i].fg.eEName = val;
+    }
+  }
+}
+
+/*
+** Resolve all symbols in the trigger at pParse->pNewTrigger, assuming
+** it was read from the schema of database zDb. Return SQLITE_OK if
+** successful. Otherwise, return an SQLite error code and leave an error
+** message in the Parse object.
+*/
+static int renameResolveTrigger(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  Trigger *pNew = pParse->pNewTrigger;
+  TriggerStep *pStep;
+  NameContext sNC;
+  int rc = SQLITE_OK;
+
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  assert( pNew->pTabSchema );
+  pParse->pTriggerTab = sqlite3FindTable(db, pNew->table,
+      db->aDb[sqlite3SchemaToIndex(db, pNew->pTabSchema)].zDbSName
+  );
+  pParse->eTriggerOp = pNew->op;
+  /* ALWAYS() because if the table of the trigger does not exist, the
+  ** error would have been hit before this point */
+  if( ALWAYS(pParse->pTriggerTab) ){
+    rc = sqlite3ViewGetColumnNames(pParse, pParse->pTriggerTab)!=0;
+  }
+
+  /* Resolve symbols in WHEN clause */
+  if( rc==SQLITE_OK && pNew->pWhen ){
+    rc = sqlite3ResolveExprNames(&sNC, pNew->pWhen);
+  }
+
+  for(pStep=pNew->step_list; rc==SQLITE_OK && pStep; pStep=pStep->pNext){
+    if( pStep->pSelect ){
+      sqlite3SelectPrep(pParse, pStep->pSelect, &sNC);
+      if( pParse->nErr ) rc = pParse->rc;
+    }
+    if( rc==SQLITE_OK && pStep->zTarget ){
+      SrcList *pSrc = sqlite3TriggerStepSrc(pParse, pStep);
+      if( pSrc ){
+        Select *pSel = sqlite3SelectNew(
+            pParse, pStep->pExprList, pSrc, 0, 0, 0, 0, 0, 0
+        );
+        if( pSel==0 ){
+          pStep->pExprList = 0;
+          pSrc = 0;
+          rc = SQLITE_NOMEM;
+        }else{
+          /* pStep->pExprList contains an expression-list used for an UPDATE
+          ** statement. So the a[].zEName values are the RHS of the
+          ** "<col> = <expr>" clauses of the UPDATE statement. So, before
+          ** running SelectPrep(), change all the eEName values in
+          ** pStep->pExprList to ENAME_SPAN (from their current value of
+          ** ENAME_NAME). This is to prevent any ids in ON() clauses that are
+          ** part of pSrc from being incorrectly resolved against the
+          ** a[].zEName values as if they were column aliases.  */
+          renameSetENames(pStep->pExprList, ENAME_SPAN);
+          sqlite3SelectPrep(pParse, pSel, 0);
+          renameSetENames(pStep->pExprList, ENAME_NAME);
+          rc = pParse->nErr ? SQLITE_ERROR : SQLITE_OK;
+          assert( pStep->pExprList==0 || pStep->pExprList==pSel->pEList );
+          assert( pSrc==pSel->pSrc );
+          if( pStep->pExprList ) pSel->pEList = 0;
+          pSel->pSrc = 0;
+          sqlite3SelectDelete(db, pSel);
+        }
+        if( pStep->pFrom ){
+          int i;
+          for(i=0; i<pStep->pFrom->nSrc && rc==SQLITE_OK; i++){
+            SrcItem *p = &pStep->pFrom->a[i];
+            if( p->fg.isSubquery ){
+              assert( p->u4.pSubq!=0 );
+              sqlite3SelectPrep(pParse, p->u4.pSubq->pSelect, 0);
+            }
+          }
+        }
+
+        if(  db->mallocFailed ){
+          rc = SQLITE_NOMEM;
+        }
+        sNC.pSrcList = pSrc;
+        if( rc==SQLITE_OK && pStep->pWhere ){
+          rc = sqlite3ResolveExprNames(&sNC, pStep->pWhere);
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3ResolveExprListNames(&sNC, pStep->pExprList);
+        }
+        assert( !pStep->pUpsert || (!pStep->pWhere && !pStep->pExprList) );
+        if( pStep->pUpsert && rc==SQLITE_OK ){
+          Upsert *pUpsert = pStep->pUpsert;
+          pUpsert->pUpsertSrc = pSrc;
+          sNC.uNC.pUpsert = pUpsert;
+          sNC.ncFlags = NC_UUpsert;
+          rc = sqlite3ResolveExprListNames(&sNC, pUpsert->pUpsertTarget);
+          if( rc==SQLITE_OK ){
+            ExprList *pUpsertSet = pUpsert->pUpsertSet;
+            rc = sqlite3ResolveExprListNames(&sNC, pUpsertSet);
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3ResolveExprNames(&sNC, pUpsert->pUpsertWhere);
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3ResolveExprNames(&sNC, pUpsert->pUpsertTargetWhere);
+          }
+          sNC.ncFlags = 0;
+        }
+        sNC.pSrcList = 0;
+        sqlite3SrcListDelete(db, pSrc);
+      }else{
+        rc = SQLITE_NOMEM;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Invoke sqlite3WalkExpr() or sqlite3WalkSelect() on all Select or Expr
+** objects that are part of the trigger passed as the second argument.
+*/
+static void renameWalkTrigger(Walker *pWalker, Trigger *pTrigger){
+  TriggerStep *pStep;
+
+  /* Find tokens to edit in WHEN clause */
+  sqlite3WalkExpr(pWalker, pTrigger->pWhen);
+
+  /* Find tokens to edit in trigger steps */
+  for(pStep=pTrigger->step_list; pStep; pStep=pStep->pNext){
+    sqlite3WalkSelect(pWalker, pStep->pSelect);
+    sqlite3WalkExpr(pWalker, pStep->pWhere);
+    sqlite3WalkExprList(pWalker, pStep->pExprList);
+    if( pStep->pUpsert ){
+      Upsert *pUpsert = pStep->pUpsert;
+      sqlite3WalkExprList(pWalker, pUpsert->pUpsertTarget);
+      sqlite3WalkExprList(pWalker, pUpsert->pUpsertSet);
+      sqlite3WalkExpr(pWalker, pUpsert->pUpsertWhere);
+      sqlite3WalkExpr(pWalker, pUpsert->pUpsertTargetWhere);
+    }
+    if( pStep->pFrom ){
+      int i;
+      SrcList *pFrom = pStep->pFrom;
+      for(i=0; i<pFrom->nSrc; i++){
+        if( pFrom->a[i].fg.isSubquery ){
+          assert( pFrom->a[i].u4.pSubq!=0 );
+          sqlite3WalkSelect(pWalker, pFrom->a[i].u4.pSubq->pSelect);
+        }
+      }
+    }
+  }
+}
+
+/*
+** Free the contents of Parse object (*pParse). Do not free the memory
+** occupied by the Parse object itself.
+*/
+static void renameParseCleanup(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  Index *pIdx;
+  if( pParse->pVdbe ){
+    sqlite3VdbeFinalize(pParse->pVdbe);
+  }
+  sqlite3DeleteTable(db, pParse->pNewTable);
+  while( (pIdx = pParse->pNewIndex)!=0 ){
+    pParse->pNewIndex = pIdx->pNext;
+    sqlite3FreeIndex(db, pIdx);
+  }
+  sqlite3DeleteTrigger(db, pParse->pNewTrigger);
+  sqlite3DbFree(db, pParse->zErrMsg);
+  renameTokenFree(db, pParse->pRename);
+  sqlite3ParseObjectReset(pParse);
+}
+
+/*
+** SQL function:
+**
+**     sqlite_rename_column(SQL,TYPE,OBJ,DB,TABLE,COL,NEWNAME,QUOTE,TEMP)
+**
+**   0. zSql:     SQL statement to rewrite
+**   1. type:     Type of object ("table", "view" etc.)
+**   2. object:   Name of object
+**   3. Database: Database name (e.g. "main")
+**   4. Table:    Table name
+**   5. iCol:     Index of column to rename
+**   6. zNew:     New column name
+**   7. bQuote:   Non-zero if the new column name should be quoted.
+**   8. bTemp:    True if zSql comes from temp schema
+**
+** Do a column rename operation on the CREATE statement given in zSql.
+** The iCol-th column (left-most is 0) of table zTable is renamed from zCol
+** into zNew.  The name should be quoted if bQuote is true.
+**
+** This function is used internally by the ALTER TABLE RENAME COLUMN command.
+** It is only accessible to SQL created using sqlite3NestedParse().  It is
+** not reachable from ordinary SQL passed into sqlite3_prepare() unless the
+** SQLITE_TESTCTRL_INTERNAL_FUNCTIONS test setting is enabled.
+*/
+static void renameColumnFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  RenameCtx sCtx;
+  const char *zSql = (const char*)sqlite3_value_text(argv[0]);
+  const char *zDb = (const char*)sqlite3_value_text(argv[3]);
+  const char *zTable = (const char*)sqlite3_value_text(argv[4]);
+  int iCol = sqlite3_value_int(argv[5]);
+  const char *zNew = (const char*)sqlite3_value_text(argv[6]);
+  int bQuote = sqlite3_value_int(argv[7]);
+  int bTemp = sqlite3_value_int(argv[8]);
+  const char *zOld;
+  int rc;
+  Parse sParse;
+  Walker sWalker;
+  Index *pIdx;
+  int i;
+  Table *pTab;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth = db->xAuth;
+#endif
+
+  UNUSED_PARAMETER(NotUsed);
+  if( zSql==0 ) return;
+  if( zTable==0 ) return;
+  if( zNew==0 ) return;
+  if( iCol<0 ) return;
+  sqlite3BtreeEnterAll(db);
+  pTab = sqlite3FindTable(db, zTable, zDb);
+  if( pTab==0 || iCol>=pTab->nCol ){
+    sqlite3BtreeLeaveAll(db);
+    return;
+  }
+  zOld = pTab->aCol[iCol].zCnName;
+  memset(&sCtx, 0, sizeof(sCtx));
+  sCtx.iCol = ((iCol==pTab->iPKey) ? -1 : iCol);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = 0;
+#endif
+  rc = renameParseSql(&sParse, zDb, db, zSql, bTemp);
+
+  /* Find tokens that need to be replaced. */
+  memset(&sWalker, 0, sizeof(Walker));
+  sWalker.pParse = &sParse;
+  sWalker.xExprCallback = renameColumnExprCb;
+  sWalker.xSelectCallback = renameColumnSelectCb;
+  sWalker.u.pRename = &sCtx;
+
+  sCtx.pTab = pTab;
+  if( rc!=SQLITE_OK ) goto renameColumnFunc_done;
+  if( sParse.pNewTable ){
+    if( IsView(sParse.pNewTable) ){
+      Select *pSelect = sParse.pNewTable->u.view.pSelect;
+      pSelect->selFlags &= ~SF_View;
+      sParse.rc = SQLITE_OK;
+      sqlite3SelectPrep(&sParse, pSelect, 0);
+      rc = (db->mallocFailed ? SQLITE_NOMEM : sParse.rc);
+      if( rc==SQLITE_OK ){
+        sqlite3WalkSelect(&sWalker, pSelect);
+      }
+      if( rc!=SQLITE_OK ) goto renameColumnFunc_done;
+    }else if( IsOrdinaryTable(sParse.pNewTable) ){
+      /* A regular table */
+      int bFKOnly = sqlite3_stricmp(zTable, sParse.pNewTable->zName);
+      FKey *pFKey;
+      sCtx.pTab = sParse.pNewTable;
+      if( bFKOnly==0 ){
+        if( iCol<sParse.pNewTable->nCol ){
+          renameTokenFind(
+              &sParse, &sCtx, (void*)sParse.pNewTable->aCol[iCol].zCnName
+          );
+        }
+        if( sCtx.iCol<0 ){
+          renameTokenFind(&sParse, &sCtx, (void*)&sParse.pNewTable->iPKey);
+        }
+        sqlite3WalkExprList(&sWalker, sParse.pNewTable->pCheck);
+        for(pIdx=sParse.pNewTable->pIndex; pIdx; pIdx=pIdx->pNext){
+          sqlite3WalkExprList(&sWalker, pIdx->aColExpr);
+        }
+        for(pIdx=sParse.pNewIndex; pIdx; pIdx=pIdx->pNext){
+          sqlite3WalkExprList(&sWalker, pIdx->aColExpr);
+        }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+        for(i=0; i<sParse.pNewTable->nCol; i++){
+          Expr *pExpr = sqlite3ColumnExpr(sParse.pNewTable,
+                                                  &sParse.pNewTable->aCol[i]);
+          sqlite3WalkExpr(&sWalker, pExpr);
+        }
+#endif
+      }
+
+      assert( IsOrdinaryTable(sParse.pNewTable) );
+      for(pFKey=sParse.pNewTable->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+        for(i=0; i<pFKey->nCol; i++){
+          if( bFKOnly==0 && pFKey->aCol[i].iFrom==iCol ){
+            renameTokenFind(&sParse, &sCtx, (void*)&pFKey->aCol[i]);
+          }
+          if( 0==sqlite3_stricmp(pFKey->zTo, zTable)
+           && 0==sqlite3_stricmp(pFKey->aCol[i].zCol, zOld)
+          ){
+            renameTokenFind(&sParse, &sCtx, (void*)pFKey->aCol[i].zCol);
+          }
+        }
+      }
+    }
+  }else if( sParse.pNewIndex ){
+    sqlite3WalkExprList(&sWalker, sParse.pNewIndex->aColExpr);
+    sqlite3WalkExpr(&sWalker, sParse.pNewIndex->pPartIdxWhere);
+  }else{
+    /* A trigger */
+    TriggerStep *pStep;
+    rc = renameResolveTrigger(&sParse);
+    if( rc!=SQLITE_OK ) goto renameColumnFunc_done;
+
+    for(pStep=sParse.pNewTrigger->step_list; pStep; pStep=pStep->pNext){
+      if( pStep->zTarget ){
+        Table *pTarget = sqlite3LocateTable(&sParse, 0, pStep->zTarget, zDb);
+        if( pTarget==pTab ){
+          if( pStep->pUpsert ){
+            ExprList *pUpsertSet = pStep->pUpsert->pUpsertSet;
+            renameColumnElistNames(&sParse, &sCtx, pUpsertSet, zOld);
+          }
+          renameColumnIdlistNames(&sParse, &sCtx, pStep->pIdList, zOld);
+          renameColumnElistNames(&sParse, &sCtx, pStep->pExprList, zOld);
+        }
+      }
+    }
+
+
+    /* Find tokens to edit in UPDATE OF clause */
+    if( sParse.pTriggerTab==pTab ){
+      renameColumnIdlistNames(&sParse, &sCtx,sParse.pNewTrigger->pColumns,zOld);
+    }
+
+    /* Find tokens to edit in various expressions and selects */
+    renameWalkTrigger(&sWalker, sParse.pNewTrigger);
+  }
+
+  assert( rc==SQLITE_OK );
+  rc = renameEditSql(context, &sCtx, zSql, zNew, bQuote);
+
+renameColumnFunc_done:
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_ERROR && sqlite3WritableSchema(db) ){
+      sqlite3_result_value(context, argv[0]);
+    }else if( sParse.zErrMsg ){
+      renameColumnParseError(context, "", argv[1], argv[2], &sParse);
+    }else{
+      sqlite3_result_error_code(context, rc);
+    }
+  }
+
+  renameParseCleanup(&sParse);
+  renameTokenFree(db, sCtx.pList);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+  sqlite3BtreeLeaveAll(db);
+}
+
+/*
+** Walker expression callback used by "RENAME TABLE".
+*/
+static int renameTableExprCb(Walker *pWalker, Expr *pExpr){
+  RenameCtx *p = pWalker->u.pRename;
+  if( pExpr->op==TK_COLUMN
+   && ALWAYS(ExprUseYTab(pExpr))
+   && p->pTab==pExpr->y.pTab
+  ){
+    renameTokenFind(pWalker->pParse, p, (void*)&pExpr->y.pTab);
+  }
+  return WRC_Continue;
+}
+
+/*
+** Walker select callback used by "RENAME TABLE".
+*/
+static int renameTableSelectCb(Walker *pWalker, Select *pSelect){
+  int i;
+  RenameCtx *p = pWalker->u.pRename;
+  SrcList *pSrc = pSelect->pSrc;
+  if( pSelect->selFlags & (SF_View|SF_CopyCte) ){
+    testcase( pSelect->selFlags & SF_View );
+    testcase( pSelect->selFlags & SF_CopyCte );
+    return WRC_Prune;
+  }
+  if( NEVER(pSrc==0) ){
+    assert( pWalker->pParse->db->mallocFailed );
+    return WRC_Abort;
+  }
+  for(i=0; i<pSrc->nSrc; i++){
+    SrcItem *pItem = &pSrc->a[i];
+    if( pItem->pSTab==p->pTab ){
+      renameTokenFind(pWalker->pParse, p, pItem->zName);
+    }
+  }
+  renameWalkWith(pWalker, pSelect);
+
+  return WRC_Continue;
+}
+
+
+/*
+** This C function implements an SQL user function that is used by SQL code
+** generated by the ALTER TABLE ... RENAME command to modify the definition
+** of any foreign key constraints that use the table being renamed as the
+** parent table. It is passed three arguments:
+**
+**   0: The database containing the table being renamed.
+**   1. type:     Type of object ("table", "view" etc.)
+**   2. object:   Name of object
+**   3: The complete text of the schema statement being modified,
+**   4: The old name of the table being renamed, and
+**   5: The new name of the table being renamed.
+**   6: True if the schema statement comes from the temp db.
+**
+** It returns the new schema statement. For example:
+**
+** sqlite_rename_table('main', 'CREATE TABLE t1(a REFERENCES t2)','t2','t3',0)
+**       -> 'CREATE TABLE t1(a REFERENCES t3)'
+*/
+static void renameTableFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  const char *zDb = (const char*)sqlite3_value_text(argv[0]);
+  const char *zInput = (const char*)sqlite3_value_text(argv[3]);
+  const char *zOld = (const char*)sqlite3_value_text(argv[4]);
+  const char *zNew = (const char*)sqlite3_value_text(argv[5]);
+  int bTemp = sqlite3_value_int(argv[6]);
+  UNUSED_PARAMETER(NotUsed);
+
+  if( zInput && zOld && zNew ){
+    Parse sParse;
+    int rc;
+    int bQuote = 1;
+    RenameCtx sCtx;
+    Walker sWalker;
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    sqlite3_xauth xAuth = db->xAuth;
+    db->xAuth = 0;
+#endif
+
+    sqlite3BtreeEnterAll(db);
+
+    memset(&sCtx, 0, sizeof(RenameCtx));
+    sCtx.pTab = sqlite3FindTable(db, zOld, zDb);
+    memset(&sWalker, 0, sizeof(Walker));
+    sWalker.pParse = &sParse;
+    sWalker.xExprCallback = renameTableExprCb;
+    sWalker.xSelectCallback = renameTableSelectCb;
+    sWalker.u.pRename = &sCtx;
+
+    rc = renameParseSql(&sParse, zDb, db, zInput, bTemp);
+
+    if( rc==SQLITE_OK ){
+      int isLegacy = (db->flags & SQLITE_LegacyAlter);
+      if( sParse.pNewTable ){
+        Table *pTab = sParse.pNewTable;
+
+        if( IsView(pTab) ){
+          if( isLegacy==0 ){
+            Select *pSelect = pTab->u.view.pSelect;
+            NameContext sNC;
+            memset(&sNC, 0, sizeof(sNC));
+            sNC.pParse = &sParse;
+
+            assert( pSelect->selFlags & SF_View );
+            pSelect->selFlags &= ~SF_View;
+            sqlite3SelectPrep(&sParse, pTab->u.view.pSelect, &sNC);
+            if( sParse.nErr ){
+              rc = sParse.rc;
+            }else{
+              sqlite3WalkSelect(&sWalker, pTab->u.view.pSelect);
+            }
+          }
+        }else{
+          /* Modify any FK definitions to point to the new table. */
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+          if( (isLegacy==0 || (db->flags & SQLITE_ForeignKeys))
+           && !IsVirtual(pTab)
+          ){
+            FKey *pFKey;
+            assert( IsOrdinaryTable(pTab) );
+            for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+              if( sqlite3_stricmp(pFKey->zTo, zOld)==0 ){
+                renameTokenFind(&sParse, &sCtx, (void*)pFKey->zTo);
+              }
+            }
+          }
+#endif
+
+          /* If this is the table being altered, fix any table refs in CHECK
+          ** expressions. Also update the name that appears right after the
+          ** "CREATE [VIRTUAL] TABLE" bit. */
+          if( sqlite3_stricmp(zOld, pTab->zName)==0 ){
+            sCtx.pTab = pTab;
+            if( isLegacy==0 ){
+              sqlite3WalkExprList(&sWalker, pTab->pCheck);
+            }
+            renameTokenFind(&sParse, &sCtx, pTab->zName);
+          }
+        }
+      }
+
+      else if( sParse.pNewIndex ){
+        renameTokenFind(&sParse, &sCtx, sParse.pNewIndex->zName);
+        if( isLegacy==0 ){
+          sqlite3WalkExpr(&sWalker, sParse.pNewIndex->pPartIdxWhere);
+        }
+      }
+
+#ifndef SQLITE_OMIT_TRIGGER
+      else{
+        Trigger *pTrigger = sParse.pNewTrigger;
+        TriggerStep *pStep;
+        if( 0==sqlite3_stricmp(sParse.pNewTrigger->table, zOld)
+            && sCtx.pTab->pSchema==pTrigger->pTabSchema
+          ){
+          renameTokenFind(&sParse, &sCtx, sParse.pNewTrigger->table);
+        }
+
+        if( isLegacy==0 ){
+          rc = renameResolveTrigger(&sParse);
+          if( rc==SQLITE_OK ){
+            renameWalkTrigger(&sWalker, pTrigger);
+            for(pStep=pTrigger->step_list; pStep; pStep=pStep->pNext){
+              if( pStep->zTarget && 0==sqlite3_stricmp(pStep->zTarget, zOld) ){
+                renameTokenFind(&sParse, &sCtx, pStep->zTarget);
+              }
+              if( pStep->pFrom ){
+                int i;
+                for(i=0; i<pStep->pFrom->nSrc; i++){
+                  SrcItem *pItem = &pStep->pFrom->a[i];
+                  if( 0==sqlite3_stricmp(pItem->zName, zOld) ){
+                    renameTokenFind(&sParse, &sCtx, pItem->zName);
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+#endif
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = renameEditSql(context, &sCtx, zInput, zNew, bQuote);
+    }
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_ERROR && sqlite3WritableSchema(db) ){
+        sqlite3_result_value(context, argv[3]);
+      }else if( sParse.zErrMsg ){
+        renameColumnParseError(context, "", argv[1], argv[2], &sParse);
+      }else{
+        sqlite3_result_error_code(context, rc);
+      }
+    }
+
+    renameParseCleanup(&sParse);
+    renameTokenFree(db, sCtx.pList);
+    sqlite3BtreeLeaveAll(db);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    db->xAuth = xAuth;
+#endif
+  }
+
+  return;
+}
+
+static int renameQuotefixExprCb(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_STRING && (pExpr->flags & EP_DblQuoted) ){
+    renameTokenFind(pWalker->pParse, pWalker->u.pRename, (const void*)pExpr);
+  }
+  return WRC_Continue;
+}
+
+/* SQL function: sqlite_rename_quotefix(DB,SQL)
+**
+** Rewrite the DDL statement "SQL" so that any string literals that use
+** double-quotes use single quotes instead.
+**
+** Two arguments must be passed:
+**
+**   0: Database name ("main", "temp" etc.).
+**   1: SQL statement to edit.
+**
+** The returned value is the modified SQL statement. For example, given
+** the database schema:
+**
+**   CREATE TABLE t1(a, b, c);
+**
+**   SELECT sqlite_rename_quotefix('main',
+**       'CREATE VIEW v1 AS SELECT "a", "string" FROM t1'
+**   );
+**
+** returns the string:
+**
+**   CREATE VIEW v1 AS SELECT "a", 'string' FROM t1
+**
+** If there is a error in the input SQL, then raise an error, except
+** if PRAGMA writable_schema=ON, then just return the input string
+** unmodified following an error.
+*/
+static void renameQuotefixFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  char const *zDb = (const char*)sqlite3_value_text(argv[0]);
+  char const *zInput = (const char*)sqlite3_value_text(argv[1]);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth = db->xAuth;
+  db->xAuth = 0;
+#endif
+
+  sqlite3BtreeEnterAll(db);
+
+  UNUSED_PARAMETER(NotUsed);
+  if( zDb && zInput ){
+    int rc;
+    Parse sParse;
+    rc = renameParseSql(&sParse, zDb, db, zInput, 0);
+
+    if( rc==SQLITE_OK ){
+      RenameCtx sCtx;
+      Walker sWalker;
+
+      /* Walker to find tokens that need to be replaced. */
+      memset(&sCtx, 0, sizeof(RenameCtx));
+      memset(&sWalker, 0, sizeof(Walker));
+      sWalker.pParse = &sParse;
+      sWalker.xExprCallback = renameQuotefixExprCb;
+      sWalker.xSelectCallback = renameColumnSelectCb;
+      sWalker.u.pRename = &sCtx;
+
+      if( sParse.pNewTable ){
+        if( IsView(sParse.pNewTable) ){
+          Select *pSelect = sParse.pNewTable->u.view.pSelect;
+          pSelect->selFlags &= ~SF_View;
+          sParse.rc = SQLITE_OK;
+          sqlite3SelectPrep(&sParse, pSelect, 0);
+          rc = (db->mallocFailed ? SQLITE_NOMEM : sParse.rc);
+          if( rc==SQLITE_OK ){
+            sqlite3WalkSelect(&sWalker, pSelect);
+          }
+        }else{
+          int i;
+          sqlite3WalkExprList(&sWalker, sParse.pNewTable->pCheck);
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+          for(i=0; i<sParse.pNewTable->nCol; i++){
+            sqlite3WalkExpr(&sWalker,
+               sqlite3ColumnExpr(sParse.pNewTable,
+                                         &sParse.pNewTable->aCol[i]));
+          }
+#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
+        }
+      }else if( sParse.pNewIndex ){
+        sqlite3WalkExprList(&sWalker, sParse.pNewIndex->aColExpr);
+        sqlite3WalkExpr(&sWalker, sParse.pNewIndex->pPartIdxWhere);
+      }else{
+#ifndef SQLITE_OMIT_TRIGGER
+        rc = renameResolveTrigger(&sParse);
+        if( rc==SQLITE_OK ){
+          renameWalkTrigger(&sWalker, sParse.pNewTrigger);
+        }
+#endif /* SQLITE_OMIT_TRIGGER */
+      }
+
+      if( rc==SQLITE_OK ){
+        rc = renameEditSql(context, &sCtx, zInput, 0, 0);
+      }
+      renameTokenFree(db, sCtx.pList);
+    }
+    if( rc!=SQLITE_OK ){
+      if( sqlite3WritableSchema(db) && rc==SQLITE_ERROR ){
+        sqlite3_result_value(context, argv[1]);
+      }else{
+        sqlite3_result_error_code(context, rc);
+      }
+    }
+    renameParseCleanup(&sParse);
+  }
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+
+  sqlite3BtreeLeaveAll(db);
+}
+
+/* Function:  sqlite_rename_test(DB,SQL,TYPE,NAME,ISTEMP,WHEN,DQS)
+**
+** An SQL user function that checks that there are no parse or symbol
+** resolution problems in a CREATE TRIGGER|TABLE|VIEW|INDEX statement.
+** After an ALTER TABLE .. RENAME operation is performed and the schema
+** reloaded, this function is called on each SQL statement in the schema
+** to ensure that it is still usable.
+**
+**   0: Database name ("main", "temp" etc.).
+**   1: SQL statement.
+**   2: Object type ("view", "table", "trigger" or "index").
+**   3: Object name.
+**   4: True if object is from temp schema.
+**   5: "when" part of error message.
+**   6: True to disable the DQS quirk when parsing SQL.
+**
+** The return value is computed as follows:
+**
+**   A. If an error is seen and not in PRAGMA writable_schema=ON mode,
+**      then raise the error.
+**   B. Else if a trigger is created and the the table that the trigger is
+**      attached to is in database zDb, then return 1.
+**   C. Otherwise return NULL.
+*/
+static void renameTableTest(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  char const *zDb = (const char*)sqlite3_value_text(argv[0]);
+  char const *zInput = (const char*)sqlite3_value_text(argv[1]);
+  int bTemp = sqlite3_value_int(argv[4]);
+  int isLegacy = (db->flags & SQLITE_LegacyAlter);
+  char const *zWhen = (const char*)sqlite3_value_text(argv[5]);
+  int bNoDQS = sqlite3_value_int(argv[6]);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth = db->xAuth;
+  db->xAuth = 0;
+#endif
+
+  UNUSED_PARAMETER(NotUsed);
+
+  if( zDb && zInput ){
+    int rc;
+    Parse sParse;
+    int flags = db->flags;
+    if( bNoDQS ) db->flags &= ~(SQLITE_DqsDML|SQLITE_DqsDDL);
+    rc = renameParseSql(&sParse, zDb, db, zInput, bTemp);
+    db->flags |= (flags & (SQLITE_DqsDML|SQLITE_DqsDDL));
+    if( rc==SQLITE_OK ){
+      if( isLegacy==0 && sParse.pNewTable && IsView(sParse.pNewTable) ){
+        NameContext sNC;
+        memset(&sNC, 0, sizeof(sNC));
+        sNC.pParse = &sParse;
+        sqlite3SelectPrep(&sParse, sParse.pNewTable->u.view.pSelect, &sNC);
+        if( sParse.nErr ) rc = sParse.rc;
+      }
+
+      else if( sParse.pNewTrigger ){
+        if( isLegacy==0 ){
+          rc = renameResolveTrigger(&sParse);
+        }
+        if( rc==SQLITE_OK ){
+          int i1 = sqlite3SchemaToIndex(db, sParse.pNewTrigger->pTabSchema);
+          int i2 = sqlite3FindDbName(db, zDb);
+          if( i1==i2 ){
+            /* Handle output case B */
+            sqlite3_result_int(context, 1);
+          }
+        }
+      }
+    }
+
+    if( rc!=SQLITE_OK && zWhen && !sqlite3WritableSchema(db) ){
+      /* Output case A */
+      renameColumnParseError(context, zWhen, argv[2], argv[3],&sParse);
+    }
+    renameParseCleanup(&sParse);
+  }
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+}
+
+/*
+** The implementation of internal UDF sqlite_drop_column().
+**
+** Arguments:
+**
+**  argv[0]: An integer - the index of the schema containing the table
+**  argv[1]: CREATE TABLE statement to modify.
+**  argv[2]: An integer - the index of the column to remove.
+**
+** The value returned is a string containing the CREATE TABLE statement
+** with column argv[2] removed.
+*/
+static void dropColumnFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  int iSchema = sqlite3_value_int(argv[0]);
+  const char *zSql = (const char*)sqlite3_value_text(argv[1]);
+  int iCol = sqlite3_value_int(argv[2]);
+  const char *zDb = db->aDb[iSchema].zDbSName;
+  int rc;
+  Parse sParse;
+  RenameToken *pCol;
+  Table *pTab;
+  const char *zEnd;
+  char *zNew = 0;
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth = db->xAuth;
+  db->xAuth = 0;
+#endif
+
+  UNUSED_PARAMETER(NotUsed);
+  rc = renameParseSql(&sParse, zDb, db, zSql, iSchema==1);
+  if( rc!=SQLITE_OK ) goto drop_column_done;
+  pTab = sParse.pNewTable;
+  if( pTab==0 || pTab->nCol==1 || iCol>=pTab->nCol ){
+    /* This can happen if the sqlite_schema table is corrupt */
+    rc = SQLITE_CORRUPT_BKPT;
+    goto drop_column_done;
+  }
+
+  pCol = renameTokenFind(&sParse, 0, (void*)pTab->aCol[iCol].zCnName);
+  if( iCol<pTab->nCol-1 ){
+    RenameToken *pEnd;
+    pEnd = renameTokenFind(&sParse, 0, (void*)pTab->aCol[iCol+1].zCnName);
+    zEnd = (const char*)pEnd->t.z;
+  }else{
+    assert( IsOrdinaryTable(pTab) );
+    zEnd = (const char*)&zSql[pTab->u.tab.addColOffset];
+    while( ALWAYS(pCol->t.z[0]!=0) && pCol->t.z[0]!=',' ) pCol->t.z--;
+  }
+
+  zNew = sqlite3MPrintf(db, "%.*s%s", pCol->t.z-zSql, zSql, zEnd);
+  sqlite3_result_text(context, zNew, -1, SQLITE_TRANSIENT);
+  sqlite3_free(zNew);
+
+drop_column_done:
+  renameParseCleanup(&sParse);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(context, rc);
+  }
+}
+
+/*
+** This function is called by the parser upon parsing an
+**
+**     ALTER TABLE pSrc DROP COLUMN pName
+**
+** statement. Argument pSrc contains the possibly qualified name of the
+** table being edited, and token pName the name of the column to drop.
+*/
+SQLITE_PRIVATE void sqlite3AlterDropColumn(Parse *pParse, SrcList *pSrc, const Token *pName){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  Table *pTab;                    /* Table to modify */
+  int iDb;                        /* Index of db containing pTab in aDb[] */
+  const char *zDb;                /* Database containing pTab ("main" etc.) */
+  char *zCol = 0;                 /* Name of column to drop */
+  int iCol;                       /* Index of column zCol in pTab->aCol[] */
+
+  /* Look up the table being altered. */
+  assert( pParse->pNewTable==0 );
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  if( NEVER(db->mallocFailed) ) goto exit_drop_column;
+  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
+  if( !pTab ) goto exit_drop_column;
+
+  /* Make sure this is not an attempt to ALTER a view, virtual table or
+  ** system table. */
+  if( SQLITE_OK!=isAlterableTable(pParse, pTab) ) goto exit_drop_column;
+  if( SQLITE_OK!=isRealTable(pParse, pTab, 1) ) goto exit_drop_column;
+
+  /* Find the index of the column being dropped. */
+  zCol = sqlite3NameFromToken(db, pName);
+  if( zCol==0 ){
+    assert( db->mallocFailed );
+    goto exit_drop_column;
+  }
+  iCol = sqlite3ColumnIndex(pTab, zCol);
+  if( iCol<0 ){
+    sqlite3ErrorMsg(pParse, "no such column: \"%T\"", pName);
+    goto exit_drop_column;
+  }
+
+  /* Do not allow the user to drop a PRIMARY KEY column or a column
+  ** constrained by a UNIQUE constraint.  */
+  if( pTab->aCol[iCol].colFlags & (COLFLAG_PRIMKEY|COLFLAG_UNIQUE) ){
+    sqlite3ErrorMsg(pParse, "cannot drop %s column: \"%s\"",
+        (pTab->aCol[iCol].colFlags&COLFLAG_PRIMKEY) ? "PRIMARY KEY" : "UNIQUE",
+        zCol
+    );
+    goto exit_drop_column;
+  }
+
+  /* Do not allow the number of columns to go to zero */
+  if( pTab->nCol<=1 ){
+    sqlite3ErrorMsg(pParse, "cannot drop column \"%s\": no other columns exist",zCol);
+    goto exit_drop_column;
+  }
+
+  /* Edit the sqlite_schema table */
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb>=0 );
+  zDb = db->aDb[iDb].zDbSName;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, zCol) ){
+    goto exit_drop_column;
+  }
+#endif
+  renameTestSchema(pParse, zDb, iDb==1, "", 0);
+  renameFixQuotes(pParse, zDb, iDb==1);
+  sqlite3NestedParse(pParse,
+      "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE " SET "
+      "sql = sqlite_drop_column(%d, sql, %d) "
+      "WHERE (type=='table' AND tbl_name=%Q COLLATE nocase)"
+      , zDb, iDb, iCol, pTab->zName
+  );
+
+  /* Drop and reload the database schema. */
+  renameReloadSchema(pParse, iDb, INITFLAG_AlterDrop);
+  renameTestSchema(pParse, zDb, iDb==1, "after drop column", 1);
+
+  /* Edit rows of table on disk */
+  if( pParse->nErr==0 && (pTab->aCol[iCol].colFlags & COLFLAG_VIRTUAL)==0 ){
+    int i;
+    int addr;
+    int reg;
+    int regRec;
+    Index *pPk = 0;
+    int nField = 0;               /* Number of non-virtual columns after drop */
+    int iCur;
+    Vdbe *v = sqlite3GetVdbe(pParse);
+    iCur = pParse->nTab++;
+    sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite);
+    addr = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
+    reg = ++pParse->nMem;
+    if( HasRowid(pTab) ){
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, reg);
+      pParse->nMem += pTab->nCol;
+    }else{
+      pPk = sqlite3PrimaryKeyIndex(pTab);
+      pParse->nMem += pPk->nColumn;
+      for(i=0; i<pPk->nKeyCol; i++){
+        sqlite3VdbeAddOp3(v, OP_Column, iCur, i, reg+i+1);
+      }
+      nField = pPk->nKeyCol;
+    }
+    regRec = ++pParse->nMem;
+    for(i=0; i<pTab->nCol; i++){
+      if( i!=iCol && (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0 ){
+        int regOut;
+        if( pPk ){
+          int iPos = sqlite3TableColumnToIndex(pPk, i);
+          int iColPos = sqlite3TableColumnToIndex(pPk, iCol);
+          if( iPos<pPk->nKeyCol ) continue;
+          regOut = reg+1+iPos-(iPos>iColPos);
+        }else{
+          regOut = reg+1+nField;
+        }
+        if( i==pTab->iPKey ){
+          sqlite3VdbeAddOp2(v, OP_Null, 0, regOut);
+        }else{
+          char aff = pTab->aCol[i].affinity;
+          if( aff==SQLITE_AFF_REAL ){
+            pTab->aCol[i].affinity = SQLITE_AFF_NUMERIC;
+          }
+          sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, i, regOut);
+          pTab->aCol[i].affinity = aff;
+        }
+        nField++;
+      }
+    }
+    if( nField==0 ){
+      /* dbsqlfuzz 5f09e7bcc78b4954d06bf9f2400d7715f48d1fef */
+      pParse->nMem++;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, reg+1);
+      nField = 1;
+    }
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, reg+1, nField, regRec);
+    if( pPk ){
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iCur, regRec, reg+1, pPk->nKeyCol);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_Insert, iCur, regRec, reg);
+    }
+    sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION);
+
+    sqlite3VdbeAddOp2(v, OP_Next, iCur, addr+1); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr);
+  }
+
+exit_drop_column:
+  sqlite3DbFree(db, zCol);
+  sqlite3SrcListDelete(db, pSrc);
+}
+
+/*
+** Register built-in functions used to help implement ALTER TABLE
+*/
+SQLITE_PRIVATE void sqlite3AlterFunctions(void){
+  static FuncDef aAlterTableFuncs[] = {
+    INTERNAL_FUNCTION(sqlite_rename_column,  9, renameColumnFunc),
+    INTERNAL_FUNCTION(sqlite_rename_table,   7, renameTableFunc),
+    INTERNAL_FUNCTION(sqlite_rename_test,    7, renameTableTest),
+    INTERNAL_FUNCTION(sqlite_drop_column,    3, dropColumnFunc),
+    INTERNAL_FUNCTION(sqlite_rename_quotefix,2, renameQuotefixFunc),
+  };
+  sqlite3InsertBuiltinFuncs(aAlterTableFuncs, ArraySize(aAlterTableFuncs));
+}
+#endif  /* SQLITE_ALTER_TABLE */
+
+/************** End of alter.c ***********************************************/
+/************** Begin file analyze.c *****************************************/
+/*
+** 2005-07-08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code associated with the ANALYZE command.
+**
+** The ANALYZE command gather statistics about the content of tables
+** and indices.  These statistics are made available to the query planner
+** to help it make better decisions about how to perform queries.
+**
+** The following system tables are or have been supported:
+**
+**    CREATE TABLE sqlite_stat1(tbl, idx, stat);
+**    CREATE TABLE sqlite_stat2(tbl, idx, sampleno, sample);
+**    CREATE TABLE sqlite_stat3(tbl, idx, nEq, nLt, nDLt, sample);
+**    CREATE TABLE sqlite_stat4(tbl, idx, nEq, nLt, nDLt, sample);
+**
+** Additional tables might be added in future releases of SQLite.
+** The sqlite_stat2 table is not created or used unless the SQLite version
+** is between 3.6.18 and 3.7.8, inclusive, and unless SQLite is compiled
+** with SQLITE_ENABLE_STAT2.  The sqlite_stat2 table is deprecated.
+** The sqlite_stat2 table is superseded by sqlite_stat3, which is only
+** created and used by SQLite versions 3.7.9 through 3.29.0 when
+** SQLITE_ENABLE_STAT3 defined.  The functionality of sqlite_stat3
+** is a superset of sqlite_stat2 and is also now deprecated.  The
+** sqlite_stat4 is an enhanced version of sqlite_stat3 and is only
+** available when compiled with SQLITE_ENABLE_STAT4 and in SQLite
+** versions 3.8.1 and later.  STAT4 is the only variant that is still
+** supported.
+**
+** For most applications, sqlite_stat1 provides all the statistics required
+** for the query planner to make good choices.
+**
+** Format of sqlite_stat1:
+**
+** There is normally one row per index, with the index identified by the
+** name in the idx column.  The tbl column is the name of the table to
+** which the index belongs.  In each such row, the stat column will be
+** a string consisting of a list of integers.  The first integer in this
+** list is the number of rows in the index.  (This is the same as the
+** number of rows in the table, except for partial indices.)  The second
+** integer is the average number of rows in the index that have the same
+** value in the first column of the index.  The third integer is the average
+** number of rows in the index that have the same value for the first two
+** columns.  The N-th integer (for N>1) is the average number of rows in
+** the index which have the same value for the first N-1 columns.  For
+** a K-column index, there will be K+1 integers in the stat column.  If
+** the index is unique, then the last integer will be 1.
+**
+** The list of integers in the stat column can optionally be followed
+** by the keyword "unordered".  The "unordered" keyword, if it is present,
+** must be separated from the last integer by a single space.  If the
+** "unordered" keyword is present, then the query planner assumes that
+** the index is unordered and will not use the index for a range query.
+**
+** If the sqlite_stat1.idx column is NULL, then the sqlite_stat1.stat
+** column contains a single integer which is the (estimated) number of
+** rows in the table identified by sqlite_stat1.tbl.
+**
+** Format of sqlite_stat2:
+**
+** The sqlite_stat2 is only created and is only used if SQLite is compiled
+** with SQLITE_ENABLE_STAT2 and if the SQLite version number is between
+** 3.6.18 and 3.7.8.  The "stat2" table contains additional information
+** about the distribution of keys within an index.  The index is identified by
+** the "idx" column and the "tbl" column is the name of the table to which
+** the index belongs.  There are usually 10 rows in the sqlite_stat2
+** table for each index.
+**
+** The sqlite_stat2 entries for an index that have sampleno between 0 and 9
+** inclusive are samples of the left-most key value in the index taken at
+** evenly spaced points along the index.  Let the number of samples be S
+** (10 in the standard build) and let C be the number of rows in the index.
+** Then the sampled rows are given by:
+**
+**     rownumber = (i*C*2 + C)/(S*2)
+**
+** For i between 0 and S-1.  Conceptually, the index space is divided into
+** S uniform buckets and the samples are the middle row from each bucket.
+**
+** The format for sqlite_stat2 is recorded here for legacy reference.  This
+** version of SQLite does not support sqlite_stat2.  It neither reads nor
+** writes the sqlite_stat2 table.  This version of SQLite only supports
+** sqlite_stat3.
+**
+** Format for sqlite_stat3:
+**
+** The sqlite_stat3 format is a subset of sqlite_stat4.  Hence, the
+** sqlite_stat4 format will be described first.  Further information
+** about sqlite_stat3 follows the sqlite_stat4 description.
+**
+** Format for sqlite_stat4:
+**
+** As with sqlite_stat2, the sqlite_stat4 table contains histogram data
+** to aid the query planner in choosing good indices based on the values
+** that indexed columns are compared against in the WHERE clauses of
+** queries.
+**
+** The sqlite_stat4 table contains multiple entries for each index.
+** The idx column names the index and the tbl column is the table of the
+** index.  If the idx and tbl columns are the same, then the sample is
+** of the INTEGER PRIMARY KEY.  The sample column is a blob which is the
+** binary encoding of a key from the index.  The nEq column is a
+** list of integers.  The first integer is the approximate number
+** of entries in the index whose left-most column exactly matches
+** the left-most column of the sample.  The second integer in nEq
+** is the approximate number of entries in the index where the
+** first two columns match the first two columns of the sample.
+** And so forth.  nLt is another list of integers that show the approximate
+** number of entries that are strictly less than the sample.  The first
+** integer in nLt contains the number of entries in the index where the
+** left-most column is less than the left-most column of the sample.
+** The K-th integer in the nLt entry is the number of index entries
+** where the first K columns are less than the first K columns of the
+** sample.  The nDLt column is like nLt except that it contains the
+** number of distinct entries in the index that are less than the
+** sample.
+**
+** There can be an arbitrary number of sqlite_stat4 entries per index.
+** The ANALYZE command will typically generate sqlite_stat4 tables
+** that contain between 10 and 40 samples which are distributed across
+** the key space, though not uniformly, and which include samples with
+** large nEq values.
+**
+** Format for sqlite_stat3 redux:
+**
+** The sqlite_stat3 table is like sqlite_stat4 except that it only
+** looks at the left-most column of the index.  The sqlite_stat3.sample
+** column contains the actual value of the left-most column instead
+** of a blob encoding of the complete index key as is found in
+** sqlite_stat4.sample.  The nEq, nLt, and nDLt entries of sqlite_stat3
+** all contain just a single integer which is the same as the first
+** integer in the equivalent columns in sqlite_stat4.
+*/
+#ifndef SQLITE_OMIT_ANALYZE
+/* #include "sqliteInt.h" */
+
+#if defined(SQLITE_ENABLE_STAT4)
+# define IsStat4     1
+#else
+# define IsStat4     0
+# undef SQLITE_STAT4_SAMPLES
+# define SQLITE_STAT4_SAMPLES 1
+#endif
+
+/*
+** This routine generates code that opens the sqlite_statN tables.
+** The sqlite_stat1 table is always relevant.  sqlite_stat2 is now
+** obsolete.  sqlite_stat3 and sqlite_stat4 are only opened when
+** appropriate compile-time options are provided.
+**
+** If the sqlite_statN tables do not previously exist, it is created.
+**
+** Argument zWhere may be a pointer to a buffer containing a table name,
+** or it may be a NULL pointer. If it is not NULL, then all entries in
+** the sqlite_statN tables associated with the named table are deleted.
+** If zWhere==0, then code is generated to delete all stat table entries.
+*/
+static void openStatTable(
+  Parse *pParse,          /* Parsing context */
+  int iDb,                /* The database we are looking in */
+  int iStatCur,           /* Open the sqlite_stat1 table on this cursor */
+  const char *zWhere,     /* Delete entries for this table or index */
+  const char *zWhereType  /* Either "tbl" or "idx" */
+){
+  static const struct {
+    const char *zName;
+    const char *zCols;
+  } aTable[] = {
+    { "sqlite_stat1", "tbl,idx,stat" },
+#if defined(SQLITE_ENABLE_STAT4)
+    { "sqlite_stat4", "tbl,idx,neq,nlt,ndlt,sample" },
+#else
+    { "sqlite_stat4", 0 },
+#endif
+    { "sqlite_stat3", 0 },
+  };
+  int i;
+  sqlite3 *db = pParse->db;
+  Db *pDb;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  u32 aRoot[ArraySize(aTable)];
+  u8 aCreateTbl[ArraySize(aTable)];
+#ifdef SQLITE_ENABLE_STAT4
+  const int nToOpen = OptimizationEnabled(db,SQLITE_Stat4) ? 2 : 1;
+#else
+  const int nToOpen = 1;
+#endif
+
+  if( v==0 ) return;
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  assert( sqlite3VdbeDb(v)==db );
+  pDb = &db->aDb[iDb];
+
+  /* Create new statistic tables if they do not exist, or clear them
+  ** if they do already exist.
+  */
+  for(i=0; i<ArraySize(aTable); i++){
+    const char *zTab = aTable[i].zName;
+    Table *pStat;
+    aCreateTbl[i] = 0;
+    if( (pStat = sqlite3FindTable(db, zTab, pDb->zDbSName))==0 ){
+      if( i<nToOpen ){
+        /* The sqlite_statN table does not exist. Create it. Note that a
+        ** side-effect of the CREATE TABLE statement is to leave the rootpage
+        ** of the new table in register pParse->regRoot. This is important
+        ** because the OpenWrite opcode below will be needing it. */
+        sqlite3NestedParse(pParse,
+            "CREATE TABLE %Q.%s(%s)", pDb->zDbSName, zTab, aTable[i].zCols
+        );
+        aRoot[i] = (u32)pParse->regRoot;
+        aCreateTbl[i] = OPFLAG_P2ISREG;
+      }
+    }else{
+      /* The table already exists. If zWhere is not NULL, delete all entries
+      ** associated with the table zWhere. If zWhere is NULL, delete the
+      ** entire contents of the table. */
+      aRoot[i] = pStat->tnum;
+      sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab);
+      if( zWhere ){
+        sqlite3NestedParse(pParse,
+           "DELETE FROM %Q.%s WHERE %s=%Q",
+           pDb->zDbSName, zTab, zWhereType, zWhere
+        );
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+      }else if( db->xPreUpdateCallback ){
+        sqlite3NestedParse(pParse, "DELETE FROM %Q.%s", pDb->zDbSName, zTab);
+#endif
+      }else{
+        /* The sqlite_stat[134] table already exists.  Delete all rows. */
+        sqlite3VdbeAddOp2(v, OP_Clear, (int)aRoot[i], iDb);
+      }
+    }
+  }
+
+  /* Open the sqlite_stat[134] tables for writing. */
+  for(i=0; i<nToOpen; i++){
+    assert( i<ArraySize(aTable) );
+    sqlite3VdbeAddOp4Int(v, OP_OpenWrite, iStatCur+i, (int)aRoot[i], iDb, 3);
+    sqlite3VdbeChangeP5(v, aCreateTbl[i]);
+    VdbeComment((v, aTable[i].zName));
+  }
+}
+
+/*
+** Recommended number of samples for sqlite_stat4
+*/
+#ifndef SQLITE_STAT4_SAMPLES
+# define SQLITE_STAT4_SAMPLES 24
+#endif
+
+/*
+** Three SQL functions - stat_init(), stat_push(), and stat_get() -
+** share an instance of the following structure to hold their state
+** information.
+*/
+typedef struct StatAccum StatAccum;
+typedef struct StatSample StatSample;
+struct StatSample {
+  tRowcnt *anDLt;                 /* sqlite_stat4.nDLt */
+#ifdef SQLITE_ENABLE_STAT4
+  tRowcnt *anEq;                  /* sqlite_stat4.nEq */
+  tRowcnt *anLt;                  /* sqlite_stat4.nLt */
+  union {
+    i64 iRowid;                     /* Rowid in main table of the key */
+    u8 *aRowid;                     /* Key for WITHOUT ROWID tables */
+  } u;
+  u32 nRowid;                     /* Sizeof aRowid[] */
+  u8 isPSample;                   /* True if a periodic sample */
+  int iCol;                       /* If !isPSample, the reason for inclusion */
+  u32 iHash;                      /* Tiebreaker hash */
+#endif
+};
+struct StatAccum {
+  sqlite3 *db;              /* Database connection, for malloc() */
+  tRowcnt nEst;             /* Estimated number of rows */
+  tRowcnt nRow;             /* Number of rows visited so far */
+  int nLimit;               /* Analysis row-scan limit */
+  int nCol;                 /* Number of columns in index + pk/rowid */
+  int nKeyCol;              /* Number of index columns w/o the pk/rowid */
+  u8 nSkipAhead;            /* Number of times of skip-ahead */
+  StatSample current;       /* Current row as a StatSample */
+#ifdef SQLITE_ENABLE_STAT4
+  tRowcnt nPSample;         /* How often to do a periodic sample */
+  int mxSample;             /* Maximum number of samples to accumulate */
+  u32 iPrn;                 /* Pseudo-random number used for sampling */
+  StatSample *aBest;        /* Array of nCol best samples */
+  int iMin;                 /* Index in a[] of entry with minimum score */
+  int nSample;              /* Current number of samples */
+  int nMaxEqZero;           /* Max leading 0 in anEq[] for any a[] entry */
+  int iGet;                 /* Index of current sample accessed by stat_get() */
+  StatSample *a;            /* Array of mxSample StatSample objects */
+#endif
+};
+
+/* Reclaim memory used by a StatSample
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static void sampleClear(sqlite3 *db, StatSample *p){
+  assert( db!=0 );
+  if( p->nRowid ){
+    sqlite3DbFree(db, p->u.aRowid);
+    p->nRowid = 0;
+  }
+}
+#endif
+
+/* Initialize the BLOB value of a ROWID
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static void sampleSetRowid(sqlite3 *db, StatSample *p, int n, const u8 *pData){
+  assert( db!=0 );
+  if( p->nRowid ) sqlite3DbFree(db, p->u.aRowid);
+  p->u.aRowid = sqlite3DbMallocRawNN(db, n);
+  if( p->u.aRowid ){
+    p->nRowid = n;
+    memcpy(p->u.aRowid, pData, n);
+  }else{
+    p->nRowid = 0;
+  }
+}
+#endif
+
+/* Initialize the INTEGER value of a ROWID.
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static void sampleSetRowidInt64(sqlite3 *db, StatSample *p, i64 iRowid){
+  assert( db!=0 );
+  if( p->nRowid ) sqlite3DbFree(db, p->u.aRowid);
+  p->nRowid = 0;
+  p->u.iRowid = iRowid;
+}
+#endif
+
+
+/*
+** Copy the contents of object (*pFrom) into (*pTo).
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static void sampleCopy(StatAccum *p, StatSample *pTo, StatSample *pFrom){
+  pTo->isPSample = pFrom->isPSample;
+  pTo->iCol = pFrom->iCol;
+  pTo->iHash = pFrom->iHash;
+  memcpy(pTo->anEq, pFrom->anEq, sizeof(tRowcnt)*p->nCol);
+  memcpy(pTo->anLt, pFrom->anLt, sizeof(tRowcnt)*p->nCol);
+  memcpy(pTo->anDLt, pFrom->anDLt, sizeof(tRowcnt)*p->nCol);
+  if( pFrom->nRowid ){
+    sampleSetRowid(p->db, pTo, pFrom->nRowid, pFrom->u.aRowid);
+  }else{
+    sampleSetRowidInt64(p->db, pTo, pFrom->u.iRowid);
+  }
+}
+#endif
+
+/*
+** Reclaim all memory of a StatAccum structure.
+*/
+static void statAccumDestructor(void *pOld){
+  StatAccum *p = (StatAccum*)pOld;
+#ifdef SQLITE_ENABLE_STAT4
+  if( p->mxSample ){
+    int i;
+    for(i=0; i<p->nCol; i++) sampleClear(p->db, p->aBest+i);
+    for(i=0; i<p->mxSample; i++) sampleClear(p->db, p->a+i);
+    sampleClear(p->db, &p->current);
+  }
+#endif
+  sqlite3DbFree(p->db, p);
+}
+
+/*
+** Implementation of the stat_init(N,K,C,L) SQL function. The four parameters
+** are:
+**     N:    The number of columns in the index including the rowid/pk (note 1)
+**     K:    The number of columns in the index excluding the rowid/pk.
+**     C:    Estimated number of rows in the index
+**     L:    A limit on the number of rows to scan, or 0 for no-limit
+**
+** Note 1:  In the special case of the covering index that implements a
+** WITHOUT ROWID table, N is the number of PRIMARY KEY columns, not the
+** total number of columns in the table.
+**
+** For indexes on ordinary rowid tables, N==K+1.  But for indexes on
+** WITHOUT ROWID tables, N=K+P where P is the number of columns in the
+** PRIMARY KEY of the table.  The covering index that implements the
+** original WITHOUT ROWID table as N==K as a special case.
+**
+** This routine allocates the StatAccum object in heap memory. The return
+** value is a pointer to the StatAccum object.  The datatype of the
+** return value is BLOB, but it is really just a pointer to the StatAccum
+** object.
+*/
+static void statInit(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  StatAccum *p;
+  int nCol;                       /* Number of columns in index being sampled */
+  int nKeyCol;                    /* Number of key columns */
+  int nColUp;                     /* nCol rounded up for alignment */
+  int n;                          /* Bytes of space to allocate */
+  sqlite3 *db = sqlite3_context_db_handle(context);   /* Database connection */
+#ifdef SQLITE_ENABLE_STAT4
+  /* Maximum number of samples.  0 if STAT4 data is not collected */
+  int mxSample = OptimizationEnabled(db,SQLITE_Stat4) ?SQLITE_STAT4_SAMPLES :0;
+#endif
+
+  /* Decode the three function arguments */
+  UNUSED_PARAMETER(argc);
+  nCol = sqlite3_value_int(argv[0]);
+  assert( nCol>0 );
+  nColUp = sizeof(tRowcnt)<8 ? (nCol+1)&~1 : nCol;
+  nKeyCol = sqlite3_value_int(argv[1]);
+  assert( nKeyCol<=nCol );
+  assert( nKeyCol>0 );
+
+  /* Allocate the space required for the StatAccum object */
+  n = sizeof(*p)
+    + sizeof(tRowcnt)*nColUp;                    /* StatAccum.anDLt */
+#ifdef SQLITE_ENABLE_STAT4
+  n += sizeof(tRowcnt)*nColUp;                   /* StatAccum.anEq */
+  if( mxSample ){
+    n += sizeof(tRowcnt)*nColUp                  /* StatAccum.anLt */
+      + sizeof(StatSample)*(nCol+mxSample)       /* StatAccum.aBest[], a[] */
+      + sizeof(tRowcnt)*3*nColUp*(nCol+mxSample);
+  }
+#endif
+  p = sqlite3DbMallocZero(db, n);
+  if( p==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+
+  p->db = db;
+  p->nEst = sqlite3_value_int64(argv[2]);
+  p->nRow = 0;
+  p->nLimit = sqlite3_value_int64(argv[3]);
+  p->nCol = nCol;
+  p->nKeyCol = nKeyCol;
+  p->nSkipAhead = 0;
+  p->current.anDLt = (tRowcnt*)&p[1];
+
+#ifdef SQLITE_ENABLE_STAT4
+  p->current.anEq = &p->current.anDLt[nColUp];
+  p->mxSample = p->nLimit==0 ? mxSample : 0;
+  if( mxSample ){
+    u8 *pSpace;                     /* Allocated space not yet assigned */
+    int i;                          /* Used to iterate through p->aSample[] */
+
+    p->iGet = -1;
+    p->nPSample = (tRowcnt)(p->nEst/(mxSample/3+1) + 1);
+    p->current.anLt = &p->current.anEq[nColUp];
+    p->iPrn = 0x689e962d*(u32)nCol ^ 0xd0944565*(u32)sqlite3_value_int(argv[2]);
+
+    /* Set up the StatAccum.a[] and aBest[] arrays */
+    p->a = (struct StatSample*)&p->current.anLt[nColUp];
+    p->aBest = &p->a[mxSample];
+    pSpace = (u8*)(&p->a[mxSample+nCol]);
+    for(i=0; i<(mxSample+nCol); i++){
+      p->a[i].anEq = (tRowcnt *)pSpace; pSpace += (sizeof(tRowcnt) * nColUp);
+      p->a[i].anLt = (tRowcnt *)pSpace; pSpace += (sizeof(tRowcnt) * nColUp);
+      p->a[i].anDLt = (tRowcnt *)pSpace; pSpace += (sizeof(tRowcnt) * nColUp);
+    }
+    assert( (pSpace - (u8*)p)==n );
+
+    for(i=0; i<nCol; i++){
+      p->aBest[i].iCol = i;
+    }
+  }
+#endif
+
+  /* Return a pointer to the allocated object to the caller.  Note that
+  ** only the pointer (the 2nd parameter) matters.  The size of the object
+  ** (given by the 3rd parameter) is never used and can be any positive
+  ** value. */
+  sqlite3_result_blob(context, p, sizeof(*p), statAccumDestructor);
+}
+static const FuncDef statInitFuncdef = {
+  4,               /* nArg */
+  SQLITE_UTF8,     /* funcFlags */
+  0,               /* pUserData */
+  0,               /* pNext */
+  statInit,        /* xSFunc */
+  0,               /* xFinalize */
+  0, 0,            /* xValue, xInverse */
+  "stat_init",     /* zName */
+  {0}
+};
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** pNew and pOld are both candidate non-periodic samples selected for
+** the same column (pNew->iCol==pOld->iCol). Ignoring this column and
+** considering only any trailing columns and the sample hash value, this
+** function returns true if sample pNew is to be preferred over pOld.
+** In other words, if we assume that the cardinalities of the selected
+** column for pNew and pOld are equal, is pNew to be preferred over pOld.
+**
+** This function assumes that for each argument sample, the contents of
+** the anEq[] array from pSample->anEq[pSample->iCol+1] onwards are valid.
+*/
+static int sampleIsBetterPost(
+  StatAccum *pAccum,
+  StatSample *pNew,
+  StatSample *pOld
+){
+  int nCol = pAccum->nCol;
+  int i;
+  assert( pNew->iCol==pOld->iCol );
+  for(i=pNew->iCol+1; i<nCol; i++){
+    if( pNew->anEq[i]>pOld->anEq[i] ) return 1;
+    if( pNew->anEq[i]<pOld->anEq[i] ) return 0;
+  }
+  if( pNew->iHash>pOld->iHash ) return 1;
+  return 0;
+}
+#endif
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Return true if pNew is to be preferred over pOld.
+**
+** This function assumes that for each argument sample, the contents of
+** the anEq[] array from pSample->anEq[pSample->iCol] onwards are valid.
+*/
+static int sampleIsBetter(
+  StatAccum *pAccum,
+  StatSample *pNew,
+  StatSample *pOld
+){
+  tRowcnt nEqNew = pNew->anEq[pNew->iCol];
+  tRowcnt nEqOld = pOld->anEq[pOld->iCol];
+
+  assert( pOld->isPSample==0 && pNew->isPSample==0 );
+  assert( IsStat4 || (pNew->iCol==0 && pOld->iCol==0) );
+
+  if( (nEqNew>nEqOld) ) return 1;
+  if( nEqNew==nEqOld ){
+    if( pNew->iCol<pOld->iCol ) return 1;
+    return (pNew->iCol==pOld->iCol && sampleIsBetterPost(pAccum, pNew, pOld));
+  }
+  return 0;
+}
+
+/*
+** Copy the contents of sample *pNew into the p->a[] array. If necessary,
+** remove the least desirable sample from p->a[] to make room.
+*/
+static void sampleInsert(StatAccum *p, StatSample *pNew, int nEqZero){
+  StatSample *pSample = 0;
+  int i;
+
+  assert( IsStat4 || nEqZero==0 );
+
+  /* StatAccum.nMaxEqZero is set to the maximum number of leading 0
+  ** values in the anEq[] array of any sample in StatAccum.a[]. In
+  ** other words, if nMaxEqZero is n, then it is guaranteed that there
+  ** are no samples with StatSample.anEq[m]==0 for (m>=n). */
+  if( nEqZero>p->nMaxEqZero ){
+    p->nMaxEqZero = nEqZero;
+  }
+  if( pNew->isPSample==0 ){
+    StatSample *pUpgrade = 0;
+    assert( pNew->anEq[pNew->iCol]>0 );
+
+    /* This sample is being added because the prefix that ends in column
+    ** iCol occurs many times in the table. However, if we have already
+    ** added a sample that shares this prefix, there is no need to add
+    ** this one. Instead, upgrade the priority of the highest priority
+    ** existing sample that shares this prefix.  */
+    for(i=p->nSample-1; i>=0; i--){
+      StatSample *pOld = &p->a[i];
+      if( pOld->anEq[pNew->iCol]==0 ){
+        if( pOld->isPSample ) return;
+        assert( pOld->iCol>pNew->iCol );
+        assert( sampleIsBetter(p, pNew, pOld) );
+        if( pUpgrade==0 || sampleIsBetter(p, pOld, pUpgrade) ){
+          pUpgrade = pOld;
+        }
+      }
+    }
+    if( pUpgrade ){
+      pUpgrade->iCol = pNew->iCol;
+      pUpgrade->anEq[pUpgrade->iCol] = pNew->anEq[pUpgrade->iCol];
+      goto find_new_min;
+    }
+  }
+
+  /* If necessary, remove sample iMin to make room for the new sample. */
+  if( p->nSample>=p->mxSample ){
+    StatSample *pMin = &p->a[p->iMin];
+    tRowcnt *anEq = pMin->anEq;
+    tRowcnt *anLt = pMin->anLt;
+    tRowcnt *anDLt = pMin->anDLt;
+    sampleClear(p->db, pMin);
+    memmove(pMin, &pMin[1], sizeof(p->a[0])*(p->nSample-p->iMin-1));
+    pSample = &p->a[p->nSample-1];
+    pSample->nRowid = 0;
+    pSample->anEq = anEq;
+    pSample->anDLt = anDLt;
+    pSample->anLt = anLt;
+    p->nSample = p->mxSample-1;
+  }
+
+  /* The "rows less-than" for the rowid column must be greater than that
+  ** for the last sample in the p->a[] array. Otherwise, the samples would
+  ** be out of order. */
+  assert( p->nSample==0
+       || pNew->anLt[p->nCol-1] > p->a[p->nSample-1].anLt[p->nCol-1] );
+
+  /* Insert the new sample */
+  pSample = &p->a[p->nSample];
+  sampleCopy(p, pSample, pNew);
+  p->nSample++;
+
+  /* Zero the first nEqZero entries in the anEq[] array. */
+  memset(pSample->anEq, 0, sizeof(tRowcnt)*nEqZero);
+
+find_new_min:
+  if( p->nSample>=p->mxSample ){
+    int iMin = -1;
+    for(i=0; i<p->mxSample; i++){
+      if( p->a[i].isPSample ) continue;
+      if( iMin<0 || sampleIsBetter(p, &p->a[iMin], &p->a[i]) ){
+        iMin = i;
+      }
+    }
+    assert( iMin>=0 );
+    p->iMin = iMin;
+  }
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Field iChng of the index being scanned has changed. So at this point
+** p->current contains a sample that reflects the previous row of the
+** index. The value of anEq[iChng] and subsequent anEq[] elements are
+** correct at this point.
+*/
+static void samplePushPrevious(StatAccum *p, int iChng){
+  int i;
+
+  /* Check if any samples from the aBest[] array should be pushed
+  ** into IndexSample.a[] at this point.  */
+  for(i=(p->nCol-2); i>=iChng; i--){
+    StatSample *pBest = &p->aBest[i];
+    pBest->anEq[i] = p->current.anEq[i];
+    if( p->nSample<p->mxSample || sampleIsBetter(p, pBest, &p->a[p->iMin]) ){
+      sampleInsert(p, pBest, i);
+    }
+  }
+
+  /* Check that no sample contains an anEq[] entry with an index of
+  ** p->nMaxEqZero or greater set to zero. */
+  for(i=p->nSample-1; i>=0; i--){
+    int j;
+    for(j=p->nMaxEqZero; j<p->nCol; j++) assert( p->a[i].anEq[j]>0 );
+  }
+
+  /* Update the anEq[] fields of any samples already collected. */
+  if( iChng<p->nMaxEqZero ){
+    for(i=p->nSample-1; i>=0; i--){
+      int j;
+      for(j=iChng; j<p->nCol; j++){
+        if( p->a[i].anEq[j]==0 ) p->a[i].anEq[j] = p->current.anEq[j];
+      }
+    }
+    p->nMaxEqZero = iChng;
+  }
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+/*
+** Implementation of the stat_push SQL function:  stat_push(P,C,R)
+** Arguments:
+**
+**    P     Pointer to the StatAccum object created by stat_init()
+**    C     Index of left-most column to differ from previous row
+**    R     Rowid for the current row.  Might be a key record for
+**          WITHOUT ROWID tables.
+**
+** The purpose of this routine is to collect statistical data and/or
+** samples from the index being analyzed into the StatAccum object.
+** The stat_get() SQL function will be used afterwards to
+** retrieve the information gathered.
+**
+** This SQL function usually returns NULL, but might return an integer
+** if it wants the byte-code to do special processing.
+**
+** The R parameter is only used for STAT4
+*/
+static void statPush(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+
+  /* The three function arguments */
+  StatAccum *p = (StatAccum*)sqlite3_value_blob(argv[0]);
+  int iChng = sqlite3_value_int(argv[1]);
+
+  UNUSED_PARAMETER( argc );
+  UNUSED_PARAMETER( context );
+  assert( p->nCol>0 );
+  assert( iChng<p->nCol );
+
+  if( p->nRow==0 ){
+    /* This is the first call to this function. Do initialization. */
+#ifdef SQLITE_ENABLE_STAT4
+    for(i=0; i<p->nCol; i++) p->current.anEq[i] = 1;
+#endif
+  }else{
+    /* Second and subsequent calls get processed here */
+#ifdef SQLITE_ENABLE_STAT4
+    if( p->mxSample ) samplePushPrevious(p, iChng);
+#endif
+
+    /* Update anDLt[], anLt[] and anEq[] to reflect the values that apply
+    ** to the current row of the index. */
+#ifdef SQLITE_ENABLE_STAT4
+    for(i=0; i<iChng; i++){
+      p->current.anEq[i]++;
+    }
+#endif
+    for(i=iChng; i<p->nCol; i++){
+      p->current.anDLt[i]++;
+#ifdef SQLITE_ENABLE_STAT4
+      if( p->mxSample ) p->current.anLt[i] += p->current.anEq[i];
+      p->current.anEq[i] = 1;
+#endif
+    }
+  }
+
+  p->nRow++;
+#ifdef SQLITE_ENABLE_STAT4
+  if( p->mxSample ){
+    tRowcnt nLt;
+    if( sqlite3_value_type(argv[2])==SQLITE_INTEGER ){
+      sampleSetRowidInt64(p->db, &p->current, sqlite3_value_int64(argv[2]));
+    }else{
+      sampleSetRowid(p->db, &p->current, sqlite3_value_bytes(argv[2]),
+                                         sqlite3_value_blob(argv[2]));
+    }
+    p->current.iHash = p->iPrn = p->iPrn*1103515245 + 12345;
+
+    nLt = p->current.anLt[p->nCol-1];
+    /* Check if this is to be a periodic sample. If so, add it. */
+    if( (nLt/p->nPSample)!=(nLt+1)/p->nPSample ){
+      p->current.isPSample = 1;
+      p->current.iCol = 0;
+      sampleInsert(p, &p->current, p->nCol-1);
+      p->current.isPSample = 0;
+    }
+
+    /* Update the aBest[] array. */
+    for(i=0; i<(p->nCol-1); i++){
+      p->current.iCol = i;
+      if( i>=iChng || sampleIsBetterPost(p, &p->current, &p->aBest[i]) ){
+        sampleCopy(p, &p->aBest[i], &p->current);
+      }
+    }
+  }else
+#endif
+  if( p->nLimit && p->nRow>(tRowcnt)p->nLimit*(p->nSkipAhead+1) ){
+    p->nSkipAhead++;
+    sqlite3_result_int(context, p->current.anDLt[0]>0);
+  }
+}
+
+static const FuncDef statPushFuncdef = {
+  2+IsStat4,       /* nArg */
+  SQLITE_UTF8,     /* funcFlags */
+  0,               /* pUserData */
+  0,               /* pNext */
+  statPush,        /* xSFunc */
+  0,               /* xFinalize */
+  0, 0,            /* xValue, xInverse */
+  "stat_push",     /* zName */
+  {0}
+};
+
+#define STAT_GET_STAT1 0          /* "stat" column of stat1 table */
+#define STAT_GET_ROWID 1          /* "rowid" column of stat[34] entry */
+#define STAT_GET_NEQ   2          /* "neq" column of stat[34] entry */
+#define STAT_GET_NLT   3          /* "nlt" column of stat[34] entry */
+#define STAT_GET_NDLT  4          /* "ndlt" column of stat[34] entry */
+
+/*
+** Implementation of the stat_get(P,J) SQL function.  This routine is
+** used to query statistical information that has been gathered into
+** the StatAccum object by prior calls to stat_push().  The P parameter
+** has type BLOB but it is really just a pointer to the StatAccum object.
+** The content to returned is determined by the parameter J
+** which is one of the STAT_GET_xxxx values defined above.
+**
+** The stat_get(P,J) function is not available to generic SQL.  It is
+** inserted as part of a manually constructed bytecode program.  (See
+** the callStatGet() routine below.)  It is guaranteed that the P
+** parameter will always be a pointer to a StatAccum object, never a
+** NULL.
+**
+** If STAT4 is not enabled, then J is always
+** STAT_GET_STAT1 and is hence omitted and this routine becomes
+** a one-parameter function, stat_get(P), that always returns the
+** stat1 table entry information.
+*/
+static void statGet(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  StatAccum *p = (StatAccum*)sqlite3_value_blob(argv[0]);
+#ifdef SQLITE_ENABLE_STAT4
+  /* STAT4 has a parameter on this routine. */
+  int eCall = sqlite3_value_int(argv[1]);
+  assert( argc==2 );
+  assert( eCall==STAT_GET_STAT1 || eCall==STAT_GET_NEQ
+       || eCall==STAT_GET_ROWID || eCall==STAT_GET_NLT
+       || eCall==STAT_GET_NDLT
+  );
+  assert( eCall==STAT_GET_STAT1 || p->mxSample );
+  if( eCall==STAT_GET_STAT1 )
+#else
+  assert( argc==1 );
+#endif
+  {
+    /* Return the value to store in the "stat" column of the sqlite_stat1
+    ** table for this index.
+    **
+    ** The value is a string composed of a list of integers describing
+    ** the index. The first integer in the list is the total number of
+    ** entries in the index. There is one additional integer in the list
+    ** for each indexed column. This additional integer is an estimate of
+    ** the number of rows matched by a equality query on the index using
+    ** a key with the corresponding number of fields. In other words,
+    ** if the index is on columns (a,b) and the sqlite_stat1 value is
+    ** "100 10 2", then SQLite estimates that:
+    **
+    **   * the index contains 100 rows,
+    **   * "WHERE a=?" matches 10 rows, and
+    **   * "WHERE a=? AND b=?" matches 2 rows.
+    **
+    ** If D is the count of distinct values and K is the total number of
+    ** rows, then each estimate is usually computed as:
+    **
+    **        I = (K+D-1)/D
+    **
+    ** In other words, I is K/D rounded up to the next whole integer.
+    ** However, if I is between 1.0 and 1.1 (in other words if I is
+    ** close to 1.0 but just a little larger) then do not round up but
+    ** instead keep the I value at 1.0.
+    */
+    sqlite3_str sStat;   /* Text of the constructed "stat" line */
+    int i;               /* Loop counter */
+
+    sqlite3StrAccumInit(&sStat, 0, 0, 0, (p->nKeyCol+1)*100);
+    sqlite3_str_appendf(&sStat, "%llu",
+        p->nSkipAhead ? (u64)p->nEst : (u64)p->nRow);
+    for(i=0; i<p->nKeyCol; i++){
+      u64 nDistinct = p->current.anDLt[i] + 1;
+      u64 iVal = (p->nRow + nDistinct - 1) / nDistinct;
+      if( iVal==2 && p->nRow*10 <= nDistinct*11 ) iVal = 1;
+      sqlite3_str_appendf(&sStat, " %llu", iVal);
+#ifdef SQLITE_ENABLE_STAT4
+      assert( p->current.anEq[i] || p->nRow==0 );
+#endif
+    }
+    sqlite3ResultStrAccum(context, &sStat);
+  }
+#ifdef SQLITE_ENABLE_STAT4
+  else if( eCall==STAT_GET_ROWID ){
+    if( p->iGet<0 ){
+      samplePushPrevious(p, 0);
+      p->iGet = 0;
+    }
+    if( p->iGet<p->nSample ){
+      StatSample *pS = p->a + p->iGet;
+      if( pS->nRowid==0 ){
+        sqlite3_result_int64(context, pS->u.iRowid);
+      }else{
+        sqlite3_result_blob(context, pS->u.aRowid, pS->nRowid,
+                            SQLITE_TRANSIENT);
+      }
+    }
+  }else{
+    tRowcnt *aCnt = 0;
+    sqlite3_str sStat;
+    int i;
+
+    assert( p->iGet<p->nSample );
+    switch( eCall ){
+      case STAT_GET_NEQ:  aCnt = p->a[p->iGet].anEq; break;
+      case STAT_GET_NLT:  aCnt = p->a[p->iGet].anLt; break;
+      default: {
+        aCnt = p->a[p->iGet].anDLt;
+        p->iGet++;
+        break;
+      }
+    }
+    sqlite3StrAccumInit(&sStat, 0, 0, 0, p->nCol*100);
+    for(i=0; i<p->nCol; i++){
+      sqlite3_str_appendf(&sStat, "%llu ", (u64)aCnt[i]);
+    }
+    if( sStat.nChar ) sStat.nChar--;
+    sqlite3ResultStrAccum(context, &sStat);
+  }
+#endif /* SQLITE_ENABLE_STAT4 */
+#ifndef SQLITE_DEBUG
+  UNUSED_PARAMETER( argc );
+#endif
+}
+static const FuncDef statGetFuncdef = {
+  1+IsStat4,       /* nArg */
+  SQLITE_UTF8,     /* funcFlags */
+  0,               /* pUserData */
+  0,               /* pNext */
+  statGet,         /* xSFunc */
+  0,               /* xFinalize */
+  0, 0,            /* xValue, xInverse */
+  "stat_get",      /* zName */
+  {0}
+};
+
+static void callStatGet(Parse *pParse, int regStat, int iParam, int regOut){
+#ifdef SQLITE_ENABLE_STAT4
+  sqlite3VdbeAddOp2(pParse->pVdbe, OP_Integer, iParam, regStat+1);
+#elif SQLITE_DEBUG
+  assert( iParam==STAT_GET_STAT1 );
+#else
+  UNUSED_PARAMETER( iParam );
+#endif
+  assert( regOut!=regStat && regOut!=regStat+1 );
+  sqlite3VdbeAddFunctionCall(pParse, 0, regStat, regOut, 1+IsStat4,
+                             &statGetFuncdef, 0);
+}
+
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+/* Add a comment to the most recent VDBE opcode that is the name
+** of the k-th column of the pIdx index.
+*/
+static void analyzeVdbeCommentIndexWithColumnName(
+  Vdbe *v,         /* Prepared statement under construction */
+  Index *pIdx,     /* Index whose column is being loaded */
+  int k            /* Which column index */
+){
+  int i;           /* Index of column in the table */
+  assert( k>=0 && k<pIdx->nColumn );
+  i = pIdx->aiColumn[k];
+  if( NEVER(i==XN_ROWID) ){
+    VdbeComment((v,"%s.rowid",pIdx->zName));
+  }else if( i==XN_EXPR ){
+    assert( pIdx->bHasExpr );
+    VdbeComment((v,"%s.expr(%d)",pIdx->zName, k));
+  }else{
+    VdbeComment((v,"%s.%s", pIdx->zName, pIdx->pTable->aCol[i].zCnName));
+  }
+}
+#else
+# define analyzeVdbeCommentIndexWithColumnName(a,b,c)
+#endif /* SQLITE_DEBUG */
+
+/*
+** Generate code to do an analysis of all indices associated with
+** a single table.
+*/
+static void analyzeOneTable(
+  Parse *pParse,   /* Parser context */
+  Table *pTab,     /* Table whose indices are to be analyzed */
+  Index *pOnlyIdx, /* If not NULL, only analyze this one index */
+  int iStatCur,    /* Index of VdbeCursor that writes the sqlite_stat1 table */
+  int iMem,        /* Available memory locations begin here */
+  int iTab         /* Next available cursor */
+){
+  sqlite3 *db = pParse->db;    /* Database handle */
+  Index *pIdx;                 /* An index to being analyzed */
+  int iIdxCur;                 /* Cursor open on index being analyzed */
+  int iTabCur;                 /* Table cursor */
+  Vdbe *v;                     /* The virtual machine being built up */
+  int i;                       /* Loop counter */
+  int jZeroRows = -1;          /* Jump from here if number of rows is zero */
+  int iDb;                     /* Index of database containing pTab */
+  u8 needTableCnt = 1;         /* True to count the table */
+  int regNewRowid = iMem++;    /* Rowid for the inserted record */
+  int regStat = iMem++;        /* Register to hold StatAccum object */
+  int regChng = iMem++;        /* Index of changed index field */
+  int regRowid = iMem++;       /* Rowid argument passed to stat_push() */
+  int regTemp = iMem++;        /* Temporary use register */
+  int regTemp2 = iMem++;       /* Second temporary use register */
+  int regTabname = iMem++;     /* Register containing table name */
+  int regIdxname = iMem++;     /* Register containing index name */
+  int regStat1 = iMem++;       /* Value for the stat column of sqlite_stat1 */
+  int regPrev = iMem;          /* MUST BE LAST (see below) */
+#ifdef SQLITE_ENABLE_STAT4
+  int doOnce = 1;              /* Flag for a one-time computation */
+#endif
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  Table *pStat1 = 0;
+#endif
+
+  sqlite3TouchRegister(pParse, iMem);
+  assert( sqlite3NoTempsInRange(pParse, regNewRowid, iMem) );
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 || NEVER(pTab==0) ){
+    return;
+  }
+  if( !IsOrdinaryTable(pTab) ){
+    /* Do not gather statistics on views or virtual tables */
+    return;
+  }
+  if( sqlite3_strlike("sqlite\\_%", pTab->zName, '\\')==0 ){
+    /* Do not gather statistics on system tables */
+    return;
+  }
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb>=0 );
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0,
+      db->aDb[iDb].zDbSName ) ){
+    return;
+  }
+#endif
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  if( db->xPreUpdateCallback ){
+    pStat1 = (Table*)sqlite3DbMallocZero(db, sizeof(Table) + 13);
+    if( pStat1==0 ) return;
+    pStat1->zName = (char*)&pStat1[1];
+    memcpy(pStat1->zName, "sqlite_stat1", 13);
+    pStat1->nCol = 3;
+    pStat1->iPKey = -1;
+    sqlite3VdbeAddOp4(pParse->pVdbe, OP_Noop, 0, 0, 0,(char*)pStat1,P4_DYNAMIC);
+  }
+#endif
+
+  /* Establish a read-lock on the table at the shared-cache level.
+  ** Open a read-only cursor on the table. Also allocate a cursor number
+  ** to use for scanning indexes (iIdxCur). No index cursor is opened at
+  ** this time though.  */
+  sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+  iTabCur = iTab++;
+  iIdxCur = iTab++;
+  pParse->nTab = MAX(pParse->nTab, iTab);
+  sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead);
+  sqlite3VdbeLoadString(v, regTabname, pTab->zName);
+
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    int nCol;                     /* Number of columns in pIdx. "N" */
+    int addrGotoEnd;               /* Address of "OP_Rewind iIdxCur" */
+    int addrNextRow;              /* Address of "next_row:" */
+    const char *zIdxName;         /* Name of the index */
+    int nColTest;                 /* Number of columns to test for changes */
+
+    if( pOnlyIdx && pOnlyIdx!=pIdx ) continue;
+    if( pIdx->pPartIdxWhere==0 ) needTableCnt = 0;
+    if( !HasRowid(pTab) && IsPrimaryKeyIndex(pIdx) ){
+      nCol = pIdx->nKeyCol;
+      zIdxName = pTab->zName;
+      nColTest = nCol - 1;
+    }else{
+      nCol = pIdx->nColumn;
+      zIdxName = pIdx->zName;
+      nColTest = pIdx->uniqNotNull ? pIdx->nKeyCol-1 : nCol-1;
+    }
+
+    /* Populate the register containing the index name. */
+    sqlite3VdbeLoadString(v, regIdxname, zIdxName);
+    VdbeComment((v, "Analysis for %s.%s", pTab->zName, zIdxName));
+
+    /*
+    ** Pseudo-code for loop that calls stat_push():
+    **
+    **   regChng = 0
+    **   Rewind csr
+    **   if eof(csr){
+    **      stat_init() with count = 0;
+    **      goto end_of_scan;
+    **   }
+    **   count()
+    **   stat_init()
+    **   goto chng_addr_0;
+    **
+    **  next_row:
+    **   regChng = 0
+    **   if( idx(0) != regPrev(0) ) goto chng_addr_0
+    **   regChng = 1
+    **   if( idx(1) != regPrev(1) ) goto chng_addr_1
+    **   ...
+    **   regChng = N
+    **   goto chng_addr_N
+    **
+    **  chng_addr_0:
+    **   regPrev(0) = idx(0)
+    **  chng_addr_1:
+    **   regPrev(1) = idx(1)
+    **  ...
+    **
+    **  endDistinctTest:
+    **   regRowid = idx(rowid)
+    **   stat_push(P, regChng, regRowid)
+    **   Next csr
+    **   if !eof(csr) goto next_row;
+    **
+    **  end_of_scan:
+    */
+
+    /* Make sure there are enough memory cells allocated to accommodate
+    ** the regPrev array and a trailing rowid (the rowid slot is required
+    ** when building a record to insert into the sample column of
+    ** the sqlite_stat4 table.  */
+    sqlite3TouchRegister(pParse, regPrev+nColTest);
+
+    /* Open a read-only cursor on the index being analyzed. */
+    assert( iDb==sqlite3SchemaToIndex(db, pIdx->pSchema) );
+    sqlite3VdbeAddOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb);
+    sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+    VdbeComment((v, "%s", pIdx->zName));
+
+    /* Implementation of the following:
+    **
+    **   regChng = 0
+    **   Rewind csr
+    **   if eof(csr){
+    **      stat_init() with count = 0;
+    **      goto end_of_scan;
+    **   }
+    **   count()
+    **   stat_init()
+    **   goto chng_addr_0;
+    */
+    assert( regTemp2==regStat+4 );
+    sqlite3VdbeAddOp2(v, OP_Integer, db->nAnalysisLimit, regTemp2);
+
+    /* Arguments to stat_init():
+    **    (1) the number of columns in the index including the rowid
+    **        (or for a WITHOUT ROWID table, the number of PK columns),
+    **    (2) the number of columns in the key without the rowid/pk
+    **    (3) estimated number of rows in the index. */
+    sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat+1);
+    assert( regRowid==regStat+2 );
+    sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regRowid);
+    sqlite3VdbeAddOp3(v, OP_Count, iIdxCur, regTemp,
+                      OptimizationDisabled(db, SQLITE_Stat4));
+    sqlite3VdbeAddFunctionCall(pParse, 0, regStat+1, regStat, 4,
+                               &statInitFuncdef, 0);
+    addrGotoEnd = sqlite3VdbeAddOp1(v, OP_Rewind, iIdxCur);
+    VdbeCoverage(v);
+
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regChng);
+    addrNextRow = sqlite3VdbeCurrentAddr(v);
+
+    if( nColTest>0 ){
+      int endDistinctTest = sqlite3VdbeMakeLabel(pParse);
+      int *aGotoChng;               /* Array of jump instruction addresses */
+      aGotoChng = sqlite3DbMallocRawNN(db, sizeof(int)*nColTest);
+      if( aGotoChng==0 ) continue;
+
+      /*
+      **  next_row:
+      **   regChng = 0
+      **   if( idx(0) != regPrev(0) ) goto chng_addr_0
+      **   regChng = 1
+      **   if( idx(1) != regPrev(1) ) goto chng_addr_1
+      **   ...
+      **   regChng = N
+      **   goto endDistinctTest
+      */
+      sqlite3VdbeAddOp0(v, OP_Goto);
+      addrNextRow = sqlite3VdbeCurrentAddr(v);
+      if( nColTest==1 && pIdx->nKeyCol==1 && IsUniqueIndex(pIdx) ){
+        /* For a single-column UNIQUE index, once we have found a non-NULL
+        ** row, we know that all the rest will be distinct, so skip
+        ** subsequent distinctness tests. */
+        sqlite3VdbeAddOp2(v, OP_NotNull, regPrev, endDistinctTest);
+        VdbeCoverage(v);
+      }
+      for(i=0; i<nColTest; i++){
+        char *pColl = (char*)sqlite3LocateCollSeq(pParse, pIdx->azColl[i]);
+        sqlite3VdbeAddOp2(v, OP_Integer, i, regChng);
+        sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regTemp);
+        analyzeVdbeCommentIndexWithColumnName(v,pIdx,i);
+        aGotoChng[i] =
+        sqlite3VdbeAddOp4(v, OP_Ne, regTemp, 0, regPrev+i, pColl, P4_COLLSEQ);
+        sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
+        VdbeCoverage(v);
+      }
+      sqlite3VdbeAddOp2(v, OP_Integer, nColTest, regChng);
+      sqlite3VdbeGoto(v, endDistinctTest);
+
+
+      /*
+      **  chng_addr_0:
+      **   regPrev(0) = idx(0)
+      **  chng_addr_1:
+      **   regPrev(1) = idx(1)
+      **  ...
+      */
+      sqlite3VdbeJumpHere(v, addrNextRow-1);
+      for(i=0; i<nColTest; i++){
+        sqlite3VdbeJumpHere(v, aGotoChng[i]);
+        sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regPrev+i);
+        analyzeVdbeCommentIndexWithColumnName(v,pIdx,i);
+      }
+      sqlite3VdbeResolveLabel(v, endDistinctTest);
+      sqlite3DbFree(db, aGotoChng);
+    }
+
+    /*
+    **  chng_addr_N:
+    **   regRowid = idx(rowid)            // STAT4 only
+    **   stat_push(P, regChng, regRowid)  // 3rd parameter STAT4 only
+    **   Next csr
+    **   if !eof(csr) goto next_row;
+    */
+#ifdef SQLITE_ENABLE_STAT4
+    if( OptimizationEnabled(db, SQLITE_Stat4) ){
+      assert( regRowid==(regStat+2) );
+      if( HasRowid(pTab) ){
+        sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, regRowid);
+      }else{
+        Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable);
+        int j, k, regKey;
+        regKey = sqlite3GetTempRange(pParse, pPk->nKeyCol);
+        for(j=0; j<pPk->nKeyCol; j++){
+          k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[j]);
+          assert( k>=0 && k<pIdx->nColumn );
+          sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, regKey+j);
+          analyzeVdbeCommentIndexWithColumnName(v,pIdx,k);
+        }
+        sqlite3VdbeAddOp3(v, OP_MakeRecord, regKey, pPk->nKeyCol, regRowid);
+        sqlite3ReleaseTempRange(pParse, regKey, pPk->nKeyCol);
+      }
+    }
+#endif
+    assert( regChng==(regStat+1) );
+    {
+      sqlite3VdbeAddFunctionCall(pParse, 1, regStat, regTemp, 2+IsStat4,
+                                 &statPushFuncdef, 0);
+      if( db->nAnalysisLimit ){
+        int j1, j2, j3;
+        j1 = sqlite3VdbeAddOp1(v, OP_IsNull, regTemp); VdbeCoverage(v);
+        j2 = sqlite3VdbeAddOp1(v, OP_If, regTemp); VdbeCoverage(v);
+        j3 = sqlite3VdbeAddOp4Int(v, OP_SeekGT, iIdxCur, 0, regPrev, 1);
+        VdbeCoverage(v);
+        sqlite3VdbeJumpHere(v, j1);
+        sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);
+        sqlite3VdbeJumpHere(v, j2);
+        sqlite3VdbeJumpHere(v, j3);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);
+      }
+    }
+
+    /* Add the entry to the stat1 table. */
+    if( pIdx->pPartIdxWhere ){
+      /* Partial indexes might get a zero-entry in sqlite_stat1.  But
+      ** an empty table is omitted from sqlite_stat1. */
+      sqlite3VdbeJumpHere(v, addrGotoEnd);
+      addrGotoEnd = 0;
+    }
+    callStatGet(pParse, regStat, STAT_GET_STAT1, regStat1);
+    assert( "BBB"[0]==SQLITE_AFF_TEXT );
+    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "BBB", 0);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
+    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regTemp, regNewRowid);
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    sqlite3VdbeChangeP4(v, -1, (char*)pStat1, P4_TABLE);
+#endif
+    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+
+    /* Add the entries to the stat4 table. */
+#ifdef SQLITE_ENABLE_STAT4
+    if( OptimizationEnabled(db, SQLITE_Stat4) && db->nAnalysisLimit==0 ){
+      int regEq = regStat1;
+      int regLt = regStat1+1;
+      int regDLt = regStat1+2;
+      int regSample = regStat1+3;
+      int regCol = regStat1+4;
+      int regSampleRowid = regCol + nCol;
+      int addrNext;
+      int addrIsNull;
+      u8 seekOp = HasRowid(pTab) ? OP_NotExists : OP_NotFound;
+
+      /* No STAT4 data is generated if the number of rows is zero */
+      if( addrGotoEnd==0 ){
+        sqlite3VdbeAddOp2(v, OP_Cast, regStat1, SQLITE_AFF_INTEGER);
+        addrGotoEnd = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1);
+        VdbeCoverage(v);
+      }
+
+      if( doOnce ){
+        int mxCol = nCol;
+        Index *pX;
+
+        /* Compute the maximum number of columns in any index */
+        for(pX=pTab->pIndex; pX; pX=pX->pNext){
+          int nColX;                     /* Number of columns in pX */
+          if( !HasRowid(pTab) && IsPrimaryKeyIndex(pX) ){
+            nColX = pX->nKeyCol;
+          }else{
+            nColX = pX->nColumn;
+          }
+          if( nColX>mxCol ) mxCol = nColX;
+        }
+
+        /* Allocate space to compute results for the largest index */
+        sqlite3TouchRegister(pParse, regCol+mxCol);
+        doOnce = 0;
+#ifdef SQLITE_DEBUG
+        /* Verify that the call to sqlite3ClearTempRegCache() below
+        ** really is needed.
+        ** https://sqlite.org/forum/forumpost/83cb4a95a0 (2023-03-25)
+        */
+        testcase( !sqlite3NoTempsInRange(pParse, regEq, regCol+mxCol) );
+#endif
+        sqlite3ClearTempRegCache(pParse);  /* tag-20230325-1 */
+        assert( sqlite3NoTempsInRange(pParse, regEq, regCol+mxCol) );
+      }
+      assert( sqlite3NoTempsInRange(pParse, regEq, regCol+nCol) );
+
+      addrNext = sqlite3VdbeCurrentAddr(v);
+      callStatGet(pParse, regStat, STAT_GET_ROWID, regSampleRowid);
+      addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, regSampleRowid);
+      VdbeCoverage(v);
+      callStatGet(pParse, regStat, STAT_GET_NEQ, regEq);
+      callStatGet(pParse, regStat, STAT_GET_NLT, regLt);
+      callStatGet(pParse, regStat, STAT_GET_NDLT, regDLt);
+      sqlite3VdbeAddOp4Int(v, seekOp, iTabCur, addrNext, regSampleRowid, 0);
+      VdbeCoverage(v);
+      for(i=0; i<nCol; i++){
+        sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iTabCur, i, regCol+i);
+      }
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regCol, nCol, regSample);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regTabname, 6, regTemp);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur+1, regNewRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, iStatCur+1, regTemp, regNewRowid);
+      sqlite3VdbeAddOp2(v, OP_Goto, 1, addrNext); /* P1==1 for end-of-loop */
+      sqlite3VdbeJumpHere(v, addrIsNull);
+    }
+#endif /* SQLITE_ENABLE_STAT4 */
+
+    /* End of analysis */
+    if( addrGotoEnd ) sqlite3VdbeJumpHere(v, addrGotoEnd);
+  }
+
+
+  /* Create a single sqlite_stat1 entry containing NULL as the index
+  ** name and the row count as the content.
+  */
+  if( pOnlyIdx==0 && needTableCnt ){
+    VdbeComment((v, "%s", pTab->zName));
+    sqlite3VdbeAddOp2(v, OP_Count, iTabCur, regStat1);
+    jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1); VdbeCoverage(v);
+    sqlite3VdbeAddOp2(v, OP_Null, 0, regIdxname);
+    assert( "BBB"[0]==SQLITE_AFF_TEXT );
+    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "BBB", 0);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
+    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regTemp, regNewRowid);
+    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    sqlite3VdbeChangeP4(v, -1, (char*)pStat1, P4_TABLE);
+#endif
+    sqlite3VdbeJumpHere(v, jZeroRows);
+  }
+}
+
+
+/*
+** Generate code that will cause the most recent index analysis to
+** be loaded into internal hash tables where is can be used.
+*/
+static void loadAnalysis(Parse *pParse, int iDb){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp1(v, OP_LoadAnalysis, iDb);
+  }
+}
+
+/*
+** Generate code that will do an analysis of an entire database
+*/
+static void analyzeDatabase(Parse *pParse, int iDb){
+  sqlite3 *db = pParse->db;
+  Schema *pSchema = db->aDb[iDb].pSchema;    /* Schema of database iDb */
+  HashElem *k;
+  int iStatCur;
+  int iMem;
+  int iTab;
+
+  sqlite3BeginWriteOperation(pParse, 0, iDb);
+  iStatCur = pParse->nTab;
+  pParse->nTab += 3;
+  openStatTable(pParse, iDb, iStatCur, 0, 0);
+  iMem = pParse->nMem+1;
+  iTab = pParse->nTab;
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
+    Table *pTab = (Table*)sqliteHashData(k);
+    analyzeOneTable(pParse, pTab, 0, iStatCur, iMem, iTab);
+#ifdef SQLITE_ENABLE_STAT4
+    iMem = sqlite3FirstAvailableRegister(pParse, iMem);
+#else
+    assert( iMem==sqlite3FirstAvailableRegister(pParse,iMem) );
+#endif
+  }
+  loadAnalysis(pParse, iDb);
+}
+
+/*
+** Generate code that will do an analysis of a single table in
+** a database.  If pOnlyIdx is not NULL then it is a single index
+** in pTab that should be analyzed.
+*/
+static void analyzeTable(Parse *pParse, Table *pTab, Index *pOnlyIdx){
+  int iDb;
+  int iStatCur;
+
+  assert( pTab!=0 );
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  sqlite3BeginWriteOperation(pParse, 0, iDb);
+  iStatCur = pParse->nTab;
+  pParse->nTab += 3;
+  if( pOnlyIdx ){
+    openStatTable(pParse, iDb, iStatCur, pOnlyIdx->zName, "idx");
+  }else{
+    openStatTable(pParse, iDb, iStatCur, pTab->zName, "tbl");
+  }
+  analyzeOneTable(pParse, pTab, pOnlyIdx, iStatCur,pParse->nMem+1,pParse->nTab);
+  loadAnalysis(pParse, iDb);
+}
+
+/*
+** Generate code for the ANALYZE command.  The parser calls this routine
+** when it recognizes an ANALYZE command.
+**
+**        ANALYZE                            -- 1
+**        ANALYZE  <database>                -- 2
+**        ANALYZE  ?<database>.?<tablename>  -- 3
+**
+** Form 1 causes all indices in all attached databases to be analyzed.
+** Form 2 analyzes all indices the single database named.
+** Form 3 analyzes all indices associated with the named table.
+*/
+SQLITE_PRIVATE void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
+  sqlite3 *db = pParse->db;
+  int iDb;
+  int i;
+  char *z, *zDb;
+  Table *pTab;
+  Index *pIdx;
+  Token *pTableName;
+  Vdbe *v;
+
+  /* Read the database schema. If an error occurs, leave an error message
+  ** and code in pParse and return NULL. */
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    return;
+  }
+
+  assert( pName2!=0 || pName1==0 );
+  if( pName1==0 ){
+    /* Form 1:  Analyze everything */
+    for(i=0; i<db->nDb; i++){
+      if( i==1 ) continue;  /* Do not analyze the TEMP database */
+      analyzeDatabase(pParse, i);
+    }
+  }else if( pName2->n==0 && (iDb = sqlite3FindDb(db, pName1))>=0 ){
+    /* Analyze the schema named as the argument */
+    analyzeDatabase(pParse, iDb);
+  }else{
+    /* Form 3: Analyze the table or index named as an argument */
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pTableName);
+    if( iDb>=0 ){
+      zDb = pName2->n ? db->aDb[iDb].zDbSName : 0;
+      z = sqlite3NameFromToken(db, pTableName);
+      if( z ){
+        if( (pIdx = sqlite3FindIndex(db, z, zDb))!=0 ){
+          analyzeTable(pParse, pIdx->pTable, pIdx);
+        }else if( (pTab = sqlite3LocateTable(pParse, 0, z, zDb))!=0 ){
+          analyzeTable(pParse, pTab, 0);
+        }
+        sqlite3DbFree(db, z);
+      }
+    }
+  }
+  if( db->nSqlExec==0 && (v = sqlite3GetVdbe(pParse))!=0 ){
+    sqlite3VdbeAddOp0(v, OP_Expire);
+  }
+}
+
+/*
+** Used to pass information from the analyzer reader through to the
+** callback routine.
+*/
+typedef struct analysisInfo analysisInfo;
+struct analysisInfo {
+  sqlite3 *db;
+  const char *zDatabase;
+};
+
+/*
+** The first argument points to a nul-terminated string containing a
+** list of space separated integers. Read the first nOut of these into
+** the array aOut[].
+*/
+static void decodeIntArray(
+  char *zIntArray,       /* String containing int array to decode */
+  int nOut,              /* Number of slots in aOut[] */
+  tRowcnt *aOut,         /* Store integers here */
+  LogEst *aLog,          /* Or, if aOut==0, here */
+  Index *pIndex          /* Handle extra flags for this index, if not NULL */
+){
+  char *z = zIntArray;
+  int c;
+  int i;
+  tRowcnt v;
+
+#ifdef SQLITE_ENABLE_STAT4
+  if( z==0 ) z = "";
+#else
+  assert( z!=0 );
+#endif
+  for(i=0; *z && i<nOut; i++){
+    v = 0;
+    while( (c=z[0])>='0' && c<='9' ){
+      v = v*10 + c - '0';
+      z++;
+    }
+#ifdef SQLITE_ENABLE_STAT4
+    if( aOut ) aOut[i] = v;
+    if( aLog ) aLog[i] = sqlite3LogEst(v);
+#else
+    assert( aOut==0 );
+    UNUSED_PARAMETER(aOut);
+    assert( aLog!=0 );
+    aLog[i] = sqlite3LogEst(v);
+#endif
+    if( *z==' ' ) z++;
+  }
+#ifndef SQLITE_ENABLE_STAT4
+  assert( pIndex!=0 ); {
+#else
+  if( pIndex ){
+#endif
+    pIndex->bUnordered = 0;
+    pIndex->noSkipScan = 0;
+    while( z[0] ){
+      if( sqlite3_strglob("unordered*", z)==0 ){
+        pIndex->bUnordered = 1;
+      }else if( sqlite3_strglob("sz=[0-9]*", z)==0 ){
+        int sz = sqlite3Atoi(z+3);
+        if( sz<2 ) sz = 2;
+        pIndex->szIdxRow = sqlite3LogEst(sz);
+      }else if( sqlite3_strglob("noskipscan*", z)==0 ){
+        pIndex->noSkipScan = 1;
+      }
+#ifdef SQLITE_ENABLE_COSTMULT
+      else if( sqlite3_strglob("costmult=[0-9]*",z)==0 ){
+        pIndex->pTable->costMult = sqlite3LogEst(sqlite3Atoi(z+9));
+      }
+#endif
+      while( z[0]!=0 && z[0]!=' ' ) z++;
+      while( z[0]==' ' ) z++;
+    }
+
+    /* Set the bLowQual flag if the peak number of rows obtained
+    ** from a full equality match is so large that a full table scan
+    ** seems likely to be faster than using the index.
+    */
+    if( aLog[0] > 66              /* Index has more than 100 rows */
+     && aLog[0] <= aLog[nOut-1]   /* And only a single value seen */
+    ){
+      pIndex->bLowQual = 1;
+    }
+  }
+}
+
+/*
+** This callback is invoked once for each index when reading the
+** sqlite_stat1 table.
+**
+**     argv[0] = name of the table
+**     argv[1] = name of the index (might be NULL)
+**     argv[2] = results of analysis - on integer for each column
+**
+** Entries for which argv[1]==NULL simply record the number of rows in
+** the table.
+*/
+static int analysisLoader(void *pData, int argc, char **argv, char **NotUsed){
+  analysisInfo *pInfo = (analysisInfo*)pData;
+  Index *pIndex;
+  Table *pTable;
+  const char *z;
+
+  assert( argc==3 );
+  UNUSED_PARAMETER2(NotUsed, argc);
+
+  if( argv==0 || argv[0]==0 || argv[2]==0 ){
+    return 0;
+  }
+  pTable = sqlite3FindTable(pInfo->db, argv[0], pInfo->zDatabase);
+  if( pTable==0 ){
+    return 0;
+  }
+  if( argv[1]==0 ){
+    pIndex = 0;
+  }else if( sqlite3_stricmp(argv[0],argv[1])==0 ){
+    pIndex = sqlite3PrimaryKeyIndex(pTable);
+  }else{
+    pIndex = sqlite3FindIndex(pInfo->db, argv[1], pInfo->zDatabase);
+  }
+  z = argv[2];
+
+  if( pIndex ){
+    tRowcnt *aiRowEst = 0;
+    int nCol = pIndex->nKeyCol+1;
+#ifdef SQLITE_ENABLE_STAT4
+    /* Index.aiRowEst may already be set here if there are duplicate
+    ** sqlite_stat1 entries for this index. In that case just clobber
+    ** the old data with the new instead of allocating a new array.  */
+    if( pIndex->aiRowEst==0 ){
+      pIndex->aiRowEst = (tRowcnt*)sqlite3MallocZero(sizeof(tRowcnt) * nCol);
+      if( pIndex->aiRowEst==0 ) sqlite3OomFault(pInfo->db);
+    }
+    aiRowEst = pIndex->aiRowEst;
+#endif
+    pIndex->bUnordered = 0;
+    decodeIntArray((char*)z, nCol, aiRowEst, pIndex->aiRowLogEst, pIndex);
+    pIndex->hasStat1 = 1;
+    if( pIndex->pPartIdxWhere==0 ){
+      pTable->nRowLogEst = pIndex->aiRowLogEst[0];
+      pTable->tabFlags |= TF_HasStat1;
+    }
+  }else{
+    Index fakeIdx;
+    fakeIdx.szIdxRow = pTable->szTabRow;
+#ifdef SQLITE_ENABLE_COSTMULT
+    fakeIdx.pTable = pTable;
+#endif
+    decodeIntArray((char*)z, 1, 0, &pTable->nRowLogEst, &fakeIdx);
+    pTable->szTabRow = fakeIdx.szIdxRow;
+    pTable->tabFlags |= TF_HasStat1;
+  }
+
+  return 0;
+}
+
+/*
+** If the Index.aSample variable is not NULL, delete the aSample[] array
+** and its contents.
+*/
+SQLITE_PRIVATE void sqlite3DeleteIndexSamples(sqlite3 *db, Index *pIdx){
+  assert( db!=0 );
+  assert( pIdx!=0 );
+#ifdef SQLITE_ENABLE_STAT4
+  if( pIdx->aSample ){
+    int j;
+    for(j=0; j<pIdx->nSample; j++){
+      IndexSample *p = &pIdx->aSample[j];
+      sqlite3DbFree(db, p->p);
+    }
+    sqlite3DbFree(db, pIdx->aSample);
+  }
+  if( db->pnBytesFreed==0 ){
+    pIdx->nSample = 0;
+    pIdx->aSample = 0;
+  }
+#else
+  UNUSED_PARAMETER(db);
+  UNUSED_PARAMETER(pIdx);
+#endif /* SQLITE_ENABLE_STAT4 */
+}
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Populate the pIdx->aAvgEq[] array based on the samples currently
+** stored in pIdx->aSample[].
+*/
+static void initAvgEq(Index *pIdx){
+  if( pIdx ){
+    IndexSample *aSample = pIdx->aSample;
+    IndexSample *pFinal = &aSample[pIdx->nSample-1];
+    int iCol;
+    int nCol = 1;
+    if( pIdx->nSampleCol>1 ){
+      /* If this is stat4 data, then calculate aAvgEq[] values for all
+      ** sample columns except the last. The last is always set to 1, as
+      ** once the trailing PK fields are considered all index keys are
+      ** unique.  */
+      nCol = pIdx->nSampleCol-1;
+      pIdx->aAvgEq[nCol] = 1;
+    }
+    for(iCol=0; iCol<nCol; iCol++){
+      int nSample = pIdx->nSample;
+      int i;                    /* Used to iterate through samples */
+      tRowcnt sumEq = 0;        /* Sum of the nEq values */
+      tRowcnt avgEq = 0;
+      tRowcnt nRow;             /* Number of rows in index */
+      i64 nSum100 = 0;          /* Number of terms contributing to sumEq */
+      i64 nDist100;             /* Number of distinct values in index */
+
+      if( !pIdx->aiRowEst || iCol>=pIdx->nKeyCol || pIdx->aiRowEst[iCol+1]==0 ){
+        nRow = pFinal->anLt[iCol];
+        nDist100 = (i64)100 * pFinal->anDLt[iCol];
+        nSample--;
+      }else{
+        nRow = pIdx->aiRowEst[0];
+        nDist100 = ((i64)100 * pIdx->aiRowEst[0]) / pIdx->aiRowEst[iCol+1];
+      }
+      pIdx->nRowEst0 = nRow;
+
+      /* Set nSum to the number of distinct (iCol+1) field prefixes that
+      ** occur in the stat4 table for this index. Set sumEq to the sum of
+      ** the nEq values for column iCol for the same set (adding the value
+      ** only once where there exist duplicate prefixes).  */
+      for(i=0; i<nSample; i++){
+        if( i==(pIdx->nSample-1)
+         || aSample[i].anDLt[iCol]!=aSample[i+1].anDLt[iCol]
+        ){
+          sumEq += aSample[i].anEq[iCol];
+          nSum100 += 100;
+        }
+      }
+
+      if( nDist100>nSum100 && sumEq<nRow ){
+        avgEq = ((i64)100 * (nRow - sumEq))/(nDist100 - nSum100);
+      }
+      if( avgEq==0 ) avgEq = 1;
+      pIdx->aAvgEq[iCol] = avgEq;
+    }
+  }
+}
+
+/*
+** Look up an index by name.  Or, if the name of a WITHOUT ROWID table
+** is supplied instead, find the PRIMARY KEY index for that table.
+*/
+static Index *findIndexOrPrimaryKey(
+  sqlite3 *db,
+  const char *zName,
+  const char *zDb
+){
+  Index *pIdx = sqlite3FindIndex(db, zName, zDb);
+  if( pIdx==0 ){
+    Table *pTab = sqlite3FindTable(db, zName, zDb);
+    if( pTab && !HasRowid(pTab) ) pIdx = sqlite3PrimaryKeyIndex(pTab);
+  }
+  return pIdx;
+}
+
+/*
+** Load the content from either the sqlite_stat4
+** into the relevant Index.aSample[] arrays.
+**
+** Arguments zSql1 and zSql2 must point to SQL statements that return
+** data equivalent to the following:
+**
+**    zSql1: SELECT idx,count(*) FROM %Q.sqlite_stat4 GROUP BY idx
+**    zSql2: SELECT idx,neq,nlt,ndlt,sample FROM %Q.sqlite_stat4
+**
+** where %Q is replaced with the database name before the SQL is executed.
+*/
+static int loadStatTbl(
+  sqlite3 *db,                  /* Database handle */
+  const char *zSql1,            /* SQL statement 1 (see above) */
+  const char *zSql2,            /* SQL statement 2 (see above) */
+  const char *zDb               /* Database name (e.g. "main") */
+){
+  int rc;                       /* Result codes from subroutines */
+  sqlite3_stmt *pStmt = 0;      /* An SQL statement being run */
+  char *zSql;                   /* Text of the SQL statement */
+  Index *pPrevIdx = 0;          /* Previous index in the loop */
+  IndexSample *pSample;         /* A slot in pIdx->aSample[] */
+
+  assert( db->lookaside.bDisable );
+  zSql = sqlite3MPrintf(db, zSql1, zDb);
+  if( !zSql ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+  sqlite3DbFree(db, zSql);
+  if( rc ) return rc;
+
+  while( sqlite3_step(pStmt)==SQLITE_ROW ){
+    int nIdxCol = 1;              /* Number of columns in stat4 records */
+
+    char *zIndex;    /* Index name */
+    Index *pIdx;     /* Pointer to the index object */
+    int nSample;     /* Number of samples */
+    i64 nByte;       /* Bytes of space required */
+    i64 i;           /* Bytes of space required */
+    tRowcnt *pSpace; /* Available allocated memory space */
+    u8 *pPtr;        /* Available memory as a u8 for easier manipulation */
+
+    zIndex = (char *)sqlite3_column_text(pStmt, 0);
+    if( zIndex==0 ) continue;
+    nSample = sqlite3_column_int(pStmt, 1);
+    pIdx = findIndexOrPrimaryKey(db, zIndex, zDb);
+    assert( pIdx==0 || pIdx->nSample==0 );
+    if( pIdx==0 ) continue;
+    if( pIdx->aSample!=0 ){
+      /* The same index appears in sqlite_stat4 under multiple names */
+      continue;
+    }
+    assert( !HasRowid(pIdx->pTable) || pIdx->nColumn==pIdx->nKeyCol+1 );
+    if( !HasRowid(pIdx->pTable) && IsPrimaryKeyIndex(pIdx) ){
+      nIdxCol = pIdx->nKeyCol;
+    }else{
+      nIdxCol = pIdx->nColumn;
+    }
+    pIdx->nSampleCol = nIdxCol;
+    pIdx->mxSample = nSample;
+    nByte = ROUND8(sizeof(IndexSample) * nSample);
+    nByte += sizeof(tRowcnt) * nIdxCol * 3 * nSample;
+    nByte += nIdxCol * sizeof(tRowcnt);     /* Space for Index.aAvgEq[] */
+
+    pIdx->aSample = sqlite3DbMallocZero(db, nByte);
+    if( pIdx->aSample==0 ){
+      sqlite3_finalize(pStmt);
+      return SQLITE_NOMEM_BKPT;
+    }
+    pPtr = (u8*)pIdx->aSample;
+    pPtr += ROUND8(nSample*sizeof(pIdx->aSample[0]));
+    pSpace = (tRowcnt*)pPtr;
+    assert( EIGHT_BYTE_ALIGNMENT( pSpace ) );
+    pIdx->aAvgEq = pSpace; pSpace += nIdxCol;
+    pIdx->pTable->tabFlags |= TF_HasStat4;
+    for(i=0; i<nSample; i++){
+      pIdx->aSample[i].anEq = pSpace; pSpace += nIdxCol;
+      pIdx->aSample[i].anLt = pSpace; pSpace += nIdxCol;
+      pIdx->aSample[i].anDLt = pSpace; pSpace += nIdxCol;
+    }
+    assert( ((u8*)pSpace)-nByte==(u8*)(pIdx->aSample) );
+  }
+  rc = sqlite3_finalize(pStmt);
+  if( rc ) return rc;
+
+  zSql = sqlite3MPrintf(db, zSql2, zDb);
+  if( !zSql ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+  sqlite3DbFree(db, zSql);
+  if( rc ) return rc;
+
+  while( sqlite3_step(pStmt)==SQLITE_ROW ){
+    char *zIndex;                 /* Index name */
+    Index *pIdx;                  /* Pointer to the index object */
+    int nCol = 1;                 /* Number of columns in index */
+
+    zIndex = (char *)sqlite3_column_text(pStmt, 0);
+    if( zIndex==0 ) continue;
+    pIdx = findIndexOrPrimaryKey(db, zIndex, zDb);
+    if( pIdx==0 ) continue;
+    if( pIdx->nSample>=pIdx->mxSample ){
+      /* Too many slots used because the same index appears in
+      ** sqlite_stat4 using multiple names */
+      continue;
+    }
+    /* This next condition is true if data has already been loaded from
+    ** the sqlite_stat4 table. */
+    nCol = pIdx->nSampleCol;
+    if( pIdx!=pPrevIdx ){
+      initAvgEq(pPrevIdx);
+      pPrevIdx = pIdx;
+    }
+    pSample = &pIdx->aSample[pIdx->nSample];
+    decodeIntArray((char*)sqlite3_column_text(pStmt,1),nCol,pSample->anEq,0,0);
+    decodeIntArray((char*)sqlite3_column_text(pStmt,2),nCol,pSample->anLt,0,0);
+    decodeIntArray((char*)sqlite3_column_text(pStmt,3),nCol,pSample->anDLt,0,0);
+
+    /* Take a copy of the sample. Add 8 extra 0x00 bytes the end of the buffer.
+    ** This is in case the sample record is corrupted. In that case, the
+    ** sqlite3VdbeRecordCompare() may read up to two varints past the
+    ** end of the allocated buffer before it realizes it is dealing with
+    ** a corrupt record.  Or it might try to read a large integer from the
+    ** buffer.  In any case, eight 0x00 bytes prevents this from causing
+    ** a buffer overread.  */
+    pSample->n = sqlite3_column_bytes(pStmt, 4);
+    pSample->p = sqlite3DbMallocZero(db, pSample->n + 8);
+    if( pSample->p==0 ){
+      sqlite3_finalize(pStmt);
+      return SQLITE_NOMEM_BKPT;
+    }
+    if( pSample->n ){
+      memcpy(pSample->p, sqlite3_column_blob(pStmt, 4), pSample->n);
+    }
+    pIdx->nSample++;
+  }
+  rc = sqlite3_finalize(pStmt);
+  if( rc==SQLITE_OK ) initAvgEq(pPrevIdx);
+  return rc;
+}
+
+/*
+** Load content from the sqlite_stat4 table into
+** the Index.aSample[] arrays of all indices.
+*/
+static int loadStat4(sqlite3 *db, const char *zDb){
+  int rc = SQLITE_OK;             /* Result codes from subroutines */
+  const Table *pStat4;
+
+  assert( db->lookaside.bDisable );
+  if( OptimizationEnabled(db, SQLITE_Stat4)
+   && (pStat4 = sqlite3FindTable(db, "sqlite_stat4", zDb))!=0
+   && IsOrdinaryTable(pStat4)
+  ){
+    rc = loadStatTbl(db,
+      "SELECT idx,count(*) FROM %Q.sqlite_stat4 GROUP BY idx COLLATE nocase",
+      "SELECT idx,neq,nlt,ndlt,sample FROM %Q.sqlite_stat4",
+      zDb
+    );
+  }
+  return rc;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+/*
+** Load the content of the sqlite_stat1 and sqlite_stat4 tables. The
+** contents of sqlite_stat1 are used to populate the Index.aiRowEst[]
+** arrays. The contents of sqlite_stat4 are used to populate the
+** Index.aSample[] arrays.
+**
+** If the sqlite_stat1 table is not present in the database, SQLITE_ERROR
+** is returned. In this case, even if SQLITE_ENABLE_STAT4 was defined
+** during compilation and the sqlite_stat4 table is present, no data is
+** read from it.
+**
+** If SQLITE_ENABLE_STAT4 was defined during compilation and the
+** sqlite_stat4 table is not present in the database, SQLITE_ERROR is
+** returned. However, in this case, data is read from the sqlite_stat1
+** table (if it is present) before returning.
+**
+** If an OOM error occurs, this function always sets db->mallocFailed.
+** This means if the caller does not care about other errors, the return
+** code may be ignored.
+*/
+SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3 *db, int iDb){
+  analysisInfo sInfo;
+  HashElem *i;
+  char *zSql;
+  int rc = SQLITE_OK;
+  Schema *pSchema = db->aDb[iDb].pSchema;
+  const Table *pStat1;
+
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( db->aDb[iDb].pBt!=0 );
+
+  /* Clear any prior statistics */
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  for(i=sqliteHashFirst(&pSchema->tblHash); i; i=sqliteHashNext(i)){
+    Table *pTab = sqliteHashData(i);
+    pTab->tabFlags &= ~TF_HasStat1;
+  }
+  for(i=sqliteHashFirst(&pSchema->idxHash); i; i=sqliteHashNext(i)){
+    Index *pIdx = sqliteHashData(i);
+    pIdx->hasStat1 = 0;
+#ifdef SQLITE_ENABLE_STAT4
+    sqlite3DeleteIndexSamples(db, pIdx);
+    pIdx->aSample = 0;
+#endif
+  }
+
+  /* Load new statistics out of the sqlite_stat1 table */
+  sInfo.db = db;
+  sInfo.zDatabase = db->aDb[iDb].zDbSName;
+  if( (pStat1 = sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase))
+   && IsOrdinaryTable(pStat1)
+  ){
+    zSql = sqlite3MPrintf(db,
+        "SELECT tbl,idx,stat FROM %Q.sqlite_stat1", sInfo.zDatabase);
+    if( zSql==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
+      sqlite3DbFree(db, zSql);
+    }
+  }
+
+  /* Set appropriate defaults on all indexes not in the sqlite_stat1 table */
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  for(i=sqliteHashFirst(&pSchema->idxHash); i; i=sqliteHashNext(i)){
+    Index *pIdx = sqliteHashData(i);
+    if( !pIdx->hasStat1 ) sqlite3DefaultRowEst(pIdx);
+  }
+
+  /* Load the statistics from the sqlite_stat4 table. */
+#ifdef SQLITE_ENABLE_STAT4
+  if( rc==SQLITE_OK ){
+    DisableLookaside;
+    rc = loadStat4(db, sInfo.zDatabase);
+    EnableLookaside;
+  }
+  for(i=sqliteHashFirst(&pSchema->idxHash); i; i=sqliteHashNext(i)){
+    Index *pIdx = sqliteHashData(i);
+    sqlite3_free(pIdx->aiRowEst);
+    pIdx->aiRowEst = 0;
+  }
+#endif
+
+  if( rc==SQLITE_NOMEM ){
+    sqlite3OomFault(db);
+  }
+  return rc;
+}
+
+
+#endif /* SQLITE_OMIT_ANALYZE */
+
+/************** End of analyze.c *********************************************/
+/************** Begin file attach.c ******************************************/
+/*
+** 2003 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the ATTACH and DETACH commands.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_ATTACH
+/*
+** Resolve an expression that was part of an ATTACH or DETACH statement. This
+** is slightly different from resolving a normal SQL expression, because simple
+** identifiers are treated as strings, not possible column names or aliases.
+**
+** i.e. if the parser sees:
+**
+**     ATTACH DATABASE abc AS def
+**
+** it treats the two expressions as literal strings 'abc' and 'def' instead of
+** looking for columns of the same name.
+**
+** This only applies to the root node of pExpr, so the statement:
+**
+**     ATTACH DATABASE abc||def AS 'db2'
+**
+** will fail because neither abc or def can be resolved.
+*/
+static int resolveAttachExpr(NameContext *pName, Expr *pExpr)
+{
+  int rc = SQLITE_OK;
+  if( pExpr ){
+    if( pExpr->op!=TK_ID ){
+      rc = sqlite3ResolveExprNames(pName, pExpr);
+    }else{
+      pExpr->op = TK_STRING;
+    }
+  }
+  return rc;
+}
+
+/*
+** Return true if zName points to a name that may be used to refer to
+** database iDb attached to handle db.
+*/
+SQLITE_PRIVATE int sqlite3DbIsNamed(sqlite3 *db, int iDb, const char *zName){
+  return (
+      sqlite3StrICmp(db->aDb[iDb].zDbSName, zName)==0
+   || (iDb==0 && sqlite3StrICmp("main", zName)==0)
+  );
+}
+
+/*
+** An SQL user-function registered to do the work of an ATTACH statement. The
+** three arguments to the function come directly from an attach statement:
+**
+**     ATTACH DATABASE x AS y KEY z
+**
+**     SELECT sqlite_attach(x, y, z)
+**
+** If the optional "KEY z" syntax is omitted, an SQL NULL is passed as the
+** third argument.
+**
+** If the db->init.reopenMemdb flags is set, then instead of attaching a
+** new database, close the database on db->init.iDb and reopen it as an
+** empty MemDB.
+*/
+static void attachFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  int i;
+  int rc = 0;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  const char *zName;
+  const char *zFile;
+  char *zPath = 0;
+  char *zErr = 0;
+  unsigned int flags;
+  Db *aNew;                 /* New array of Db pointers */
+  Db *pNew = 0;             /* Db object for the newly attached database */
+  char *zErrDyn = 0;
+  sqlite3_vfs *pVfs;
+
+  UNUSED_PARAMETER(NotUsed);
+  zFile = (const char *)sqlite3_value_text(argv[0]);
+  zName = (const char *)sqlite3_value_text(argv[1]);
+  if( zFile==0 ) zFile = "";
+  if( zName==0 ) zName = "";
+
+#ifndef SQLITE_OMIT_DESERIALIZE
+# define REOPEN_AS_MEMDB(db)  (db->init.reopenMemdb)
+#else
+# define REOPEN_AS_MEMDB(db)  (0)
+#endif
+
+  if( REOPEN_AS_MEMDB(db) ){
+    /* This is not a real ATTACH.  Instead, this routine is being called
+    ** from sqlite3_deserialize() to close database db->init.iDb and
+    ** reopen it as a MemDB */
+    Btree *pNewBt = 0;
+    pVfs = sqlite3_vfs_find("memdb");
+    if( pVfs==0 ) return;
+    rc = sqlite3BtreeOpen(pVfs, "x\0", db, &pNewBt, 0, SQLITE_OPEN_MAIN_DB);
+    if( rc==SQLITE_OK ){
+      Schema *pNewSchema = sqlite3SchemaGet(db, pNewBt);
+      if( pNewSchema ){
+        /* Both the Btree and the new Schema were allocated successfully.
+        ** Close the old db and update the aDb[] slot with the new memdb
+        ** values.  */
+        pNew = &db->aDb[db->init.iDb];
+        if( ALWAYS(pNew->pBt) ) sqlite3BtreeClose(pNew->pBt);
+        pNew->pBt = pNewBt;
+        pNew->pSchema = pNewSchema;
+      }else{
+        sqlite3BtreeClose(pNewBt);
+        rc = SQLITE_NOMEM;
+      }
+    }
+    if( rc ) goto attach_error;
+  }else{
+    /* This is a real ATTACH
+    **
+    ** Check for the following errors:
+    **
+    **     * Too many attached databases,
+    **     * Transaction currently open
+    **     * Specified database name already being used.
+    */
+    if( db->nDb>=db->aLimit[SQLITE_LIMIT_ATTACHED]+2 ){
+      zErrDyn = sqlite3MPrintf(db, "too many attached databases - max %d",
+        db->aLimit[SQLITE_LIMIT_ATTACHED]
+      );
+      goto attach_error;
+    }
+    for(i=0; i<db->nDb; i++){
+      assert( zName );
+      if( sqlite3DbIsNamed(db, i, zName) ){
+        zErrDyn = sqlite3MPrintf(db, "database %s is already in use", zName);
+        goto attach_error;
+      }
+    }
+
+    /* Allocate the new entry in the db->aDb[] array and initialize the schema
+    ** hash tables.
+    */
+    if( db->aDb==db->aDbStatic ){
+      aNew = sqlite3DbMallocRawNN(db, sizeof(db->aDb[0])*3 );
+      if( aNew==0 ) return;
+      memcpy(aNew, db->aDb, sizeof(db->aDb[0])*2);
+    }else{
+      aNew = sqlite3DbRealloc(db, db->aDb, sizeof(db->aDb[0])*(db->nDb+1) );
+      if( aNew==0 ) return;
+    }
+    db->aDb = aNew;
+    pNew = &db->aDb[db->nDb];
+    memset(pNew, 0, sizeof(*pNew));
+
+    /* Open the database file. If the btree is successfully opened, use
+    ** it to obtain the database schema. At this point the schema may
+    ** or may not be initialized.
+    */
+    flags = db->openFlags;
+    rc = sqlite3ParseUri(db->pVfs->zName, zFile, &flags, &pVfs, &zPath, &zErr);
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
+      sqlite3_result_error(context, zErr, -1);
+      sqlite3_free(zErr);
+      return;
+    }
+    if( (db->flags & SQLITE_AttachWrite)==0 ){
+      flags &= ~(SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE);
+      flags |= SQLITE_OPEN_READONLY;
+    }else if( (db->flags & SQLITE_AttachCreate)==0 ){
+      flags &= ~SQLITE_OPEN_CREATE;
+    }
+    assert( pVfs );
+    flags |= SQLITE_OPEN_MAIN_DB;
+    rc = sqlite3BtreeOpen(pVfs, zPath, db, &pNew->pBt, 0, flags);
+    db->nDb++;
+    pNew->zDbSName = sqlite3DbStrDup(db, zName);
+  }
+  db->noSharedCache = 0;
+  if( rc==SQLITE_CONSTRAINT ){
+    rc = SQLITE_ERROR;
+    zErrDyn = sqlite3MPrintf(db, "database is already attached");
+  }else if( rc==SQLITE_OK ){
+    Pager *pPager;
+    pNew->pSchema = sqlite3SchemaGet(db, pNew->pBt);
+    if( !pNew->pSchema ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else if( pNew->pSchema->file_format && pNew->pSchema->enc!=ENC(db) ){
+      zErrDyn = sqlite3MPrintf(db,
+        "attached databases must use the same text encoding as main database");
+      rc = SQLITE_ERROR;
+    }
+    sqlite3BtreeEnter(pNew->pBt);
+    pPager = sqlite3BtreePager(pNew->pBt);
+    sqlite3PagerLockingMode(pPager, db->dfltLockMode);
+    sqlite3BtreeSecureDelete(pNew->pBt,
+                             sqlite3BtreeSecureDelete(db->aDb[0].pBt,-1) );
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+    sqlite3BtreeSetPagerFlags(pNew->pBt,
+                      PAGER_SYNCHRONOUS_FULL | (db->flags & PAGER_FLAGS_MASK));
+#endif
+    sqlite3BtreeLeave(pNew->pBt);
+  }
+  pNew->safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
+  if( rc==SQLITE_OK && pNew->zDbSName==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  sqlite3_free_filename( zPath );
+
+  /* If the file was opened successfully, read the schema for the new database.
+  ** If this fails, or if opening the file failed, then close the file and
+  ** remove the entry from the db->aDb[] array. i.e. put everything back the
+  ** way we found it.
+  */
+  if( rc==SQLITE_OK ){
+    sqlite3BtreeEnterAll(db);
+    db->init.iDb = 0;
+    db->mDbFlags &= ~(DBFLAG_SchemaKnownOk);
+    if( !REOPEN_AS_MEMDB(db) ){
+      rc = sqlite3Init(db, &zErrDyn);
+    }
+    sqlite3BtreeLeaveAll(db);
+    assert( zErrDyn==0 || rc!=SQLITE_OK );
+  }
+  if( rc ){
+    if( ALWAYS(!REOPEN_AS_MEMDB(db)) ){
+      int iDb = db->nDb - 1;
+      assert( iDb>=2 );
+      if( db->aDb[iDb].pBt ){
+        sqlite3BtreeClose(db->aDb[iDb].pBt);
+        db->aDb[iDb].pBt = 0;
+        db->aDb[iDb].pSchema = 0;
+      }
+      sqlite3ResetAllSchemasOfConnection(db);
+      db->nDb = iDb;
+      if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
+        sqlite3OomFault(db);
+        sqlite3DbFree(db, zErrDyn);
+        zErrDyn = sqlite3MPrintf(db, "out of memory");
+      }else if( zErrDyn==0 ){
+        zErrDyn = sqlite3MPrintf(db, "unable to open database: %s", zFile);
+      }
+    }
+    goto attach_error;
+  }
+
+  return;
+
+attach_error:
+  /* Return an error if we get here */
+  if( zErrDyn ){
+    sqlite3_result_error(context, zErrDyn, -1);
+    sqlite3DbFree(db, zErrDyn);
+  }
+  if( rc ) sqlite3_result_error_code(context, rc);
+}
+
+/*
+** An SQL user-function registered to do the work of an DETACH statement. The
+** three arguments to the function come directly from a detach statement:
+**
+**     DETACH DATABASE x
+**
+**     SELECT sqlite_detach(x)
+*/
+static void detachFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  const char *zName = (const char *)sqlite3_value_text(argv[0]);
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  int i;
+  Db *pDb = 0;
+  HashElem *pEntry;
+  char zErr[128];
+
+  UNUSED_PARAMETER(NotUsed);
+
+  if( zName==0 ) zName = "";
+  for(i=0; i<db->nDb; i++){
+    pDb = &db->aDb[i];
+    if( pDb->pBt==0 ) continue;
+    if( sqlite3DbIsNamed(db, i, zName) ) break;
+  }
+
+  if( i>=db->nDb ){
+    sqlite3_snprintf(sizeof(zErr),zErr, "no such database: %s", zName);
+    goto detach_error;
+  }
+  if( i<2 ){
+    sqlite3_snprintf(sizeof(zErr),zErr, "cannot detach database %s", zName);
+    goto detach_error;
+  }
+  if( sqlite3BtreeTxnState(pDb->pBt)!=SQLITE_TXN_NONE
+   || sqlite3BtreeIsInBackup(pDb->pBt)
+  ){
+    sqlite3_snprintf(sizeof(zErr),zErr, "database %s is locked", zName);
+    goto detach_error;
+  }
+
+  /* If any TEMP triggers reference the schema being detached, move those
+  ** triggers to reference the TEMP schema itself. */
+  assert( db->aDb[1].pSchema );
+  pEntry = sqliteHashFirst(&db->aDb[1].pSchema->trigHash);
+  while( pEntry ){
+    Trigger *pTrig = (Trigger*)sqliteHashData(pEntry);
+    if( pTrig->pTabSchema==pDb->pSchema ){
+      pTrig->pTabSchema = pTrig->pSchema;
+    }
+    pEntry = sqliteHashNext(pEntry);
+  }
+
+  sqlite3BtreeClose(pDb->pBt);
+  pDb->pBt = 0;
+  pDb->pSchema = 0;
+  sqlite3CollapseDatabaseArray(db);
+  return;
+
+detach_error:
+  sqlite3_result_error(context, zErr, -1);
+}
+
+/*
+** This procedure generates VDBE code for a single invocation of either the
+** sqlite_detach() or sqlite_attach() SQL user functions.
+*/
+static void codeAttach(
+  Parse *pParse,       /* The parser context */
+  int type,            /* Either SQLITE_ATTACH or SQLITE_DETACH */
+  FuncDef const *pFunc,/* FuncDef wrapper for detachFunc() or attachFunc() */
+  Expr *pAuthArg,      /* Expression to pass to authorization callback */
+  Expr *pFilename,     /* Name of database file */
+  Expr *pDbname,       /* Name of the database to use internally */
+  Expr *pKey           /* Database key for encryption extension */
+){
+  int rc;
+  NameContext sName;
+  Vdbe *v;
+  sqlite3* db = pParse->db;
+  int regArgs;
+
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ) goto attach_end;
+
+  if( pParse->nErr ) goto attach_end;
+  memset(&sName, 0, sizeof(NameContext));
+  sName.pParse = pParse;
+
+  if(
+      SQLITE_OK!=resolveAttachExpr(&sName, pFilename) ||
+      SQLITE_OK!=resolveAttachExpr(&sName, pDbname) ||
+      SQLITE_OK!=resolveAttachExpr(&sName, pKey)
+  ){
+    goto attach_end;
+  }
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( ALWAYS(pAuthArg) ){
+    char *zAuthArg;
+    if( pAuthArg->op==TK_STRING ){
+      assert( !ExprHasProperty(pAuthArg, EP_IntValue) );
+      zAuthArg = pAuthArg->u.zToken;
+    }else{
+      zAuthArg = 0;
+    }
+    rc = sqlite3AuthCheck(pParse, type, zAuthArg, 0, 0);
+    if(rc!=SQLITE_OK ){
+      goto attach_end;
+    }
+  }
+#endif /* SQLITE_OMIT_AUTHORIZATION */
+
+
+  v = sqlite3GetVdbe(pParse);
+  regArgs = sqlite3GetTempRange(pParse, 4);
+  sqlite3ExprCode(pParse, pFilename, regArgs);
+  sqlite3ExprCode(pParse, pDbname, regArgs+1);
+  sqlite3ExprCode(pParse, pKey, regArgs+2);
+
+  assert( v || db->mallocFailed );
+  if( v ){
+    sqlite3VdbeAddFunctionCall(pParse, 0, regArgs+3-pFunc->nArg, regArgs+3,
+                               pFunc->nArg, pFunc, 0);
+    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
+    ** statement only). For DETACH, set it to false (expire all existing
+    ** statements).
+    */
+    sqlite3VdbeAddOp1(v, OP_Expire, (type==SQLITE_ATTACH));
+  }
+
+attach_end:
+  sqlite3ExprDelete(db, pFilename);
+  sqlite3ExprDelete(db, pDbname);
+  sqlite3ExprDelete(db, pKey);
+}
+
+/*
+** Called by the parser to compile a DETACH statement.
+**
+**     DETACH pDbname
+*/
+SQLITE_PRIVATE void sqlite3Detach(Parse *pParse, Expr *pDbname){
+  static const FuncDef detach_func = {
+    1,                /* nArg */
+    SQLITE_UTF8,      /* funcFlags */
+    0,                /* pUserData */
+    0,                /* pNext */
+    detachFunc,       /* xSFunc */
+    0,                /* xFinalize */
+    0, 0,             /* xValue, xInverse */
+    "sqlite_detach",  /* zName */
+    {0}
+  };
+  codeAttach(pParse, SQLITE_DETACH, &detach_func, pDbname, 0, 0, pDbname);
+}
+
+/*
+** Called by the parser to compile an ATTACH statement.
+**
+**     ATTACH p AS pDbname KEY pKey
+*/
+SQLITE_PRIVATE void sqlite3Attach(Parse *pParse, Expr *p, Expr *pDbname, Expr *pKey){
+  static const FuncDef attach_func = {
+    3,                /* nArg */
+    SQLITE_UTF8,      /* funcFlags */
+    0,                /* pUserData */
+    0,                /* pNext */
+    attachFunc,       /* xSFunc */
+    0,                /* xFinalize */
+    0, 0,             /* xValue, xInverse */
+    "sqlite_attach",  /* zName */
+    {0}
+  };
+  codeAttach(pParse, SQLITE_ATTACH, &attach_func, p, p, pDbname, pKey);
+}
+#endif /* SQLITE_OMIT_ATTACH */
+
+/*
+** Expression callback used by sqlite3FixAAAA() routines.
+*/
+static int fixExprCb(Walker *p, Expr *pExpr){
+  DbFixer *pFix = p->u.pFix;
+  if( !pFix->bTemp ) ExprSetProperty(pExpr, EP_FromDDL);
+  if( pExpr->op==TK_VARIABLE ){
+    if( pFix->pParse->db->init.busy ){
+      pExpr->op = TK_NULL;
+    }else{
+      sqlite3ErrorMsg(pFix->pParse, "%s cannot use variables", pFix->zType);
+      return WRC_Abort;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Select callback used by sqlite3FixAAAA() routines.
+*/
+static int fixSelectCb(Walker *p, Select *pSelect){
+  DbFixer *pFix = p->u.pFix;
+  int i;
+  SrcItem *pItem;
+  sqlite3 *db = pFix->pParse->db;
+  int iDb = sqlite3FindDbName(db, pFix->zDb);
+  SrcList *pList = pSelect->pSrc;
+
+  if( NEVER(pList==0) ) return WRC_Continue;
+  for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
+    if( pFix->bTemp==0 && pItem->fg.isSubquery==0 ){
+      if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+        if( iDb!=sqlite3FindDbName(db, pItem->u4.zDatabase) ){
+          sqlite3ErrorMsg(pFix->pParse,
+              "%s %T cannot reference objects in database %s",
+              pFix->zType, pFix->pName, pItem->u4.zDatabase);
+          return WRC_Abort;
+        }
+        sqlite3DbFree(db, pItem->u4.zDatabase);
+        pItem->fg.notCte = 1;
+        pItem->fg.hadSchema = 1;
+      }
+      pItem->u4.pSchema = pFix->pSchema;
+      pItem->fg.fromDDL = 1;
+      pItem->fg.fixedSchema = 1;
+    }
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
+    if( pList->a[i].fg.isUsing==0
+     && sqlite3WalkExpr(&pFix->w, pList->a[i].u3.pOn)
+    ){
+      return WRC_Abort;
+    }
+#endif
+  }
+  if( pSelect->pWith ){
+    for(i=0; i<pSelect->pWith->nCte; i++){
+      if( sqlite3WalkSelect(p, pSelect->pWith->a[i].pSelect) ){
+        return WRC_Abort;
+      }
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Initialize a DbFixer structure.  This routine must be called prior
+** to passing the structure to one of the sqliteFixAAAA() routines below.
+*/
+SQLITE_PRIVATE void sqlite3FixInit(
+  DbFixer *pFix,      /* The fixer to be initialized */
+  Parse *pParse,      /* Error messages will be written here */
+  int iDb,            /* This is the database that must be used */
+  const char *zType,  /* "view", "trigger", or "index" */
+  const Token *pName  /* Name of the view, trigger, or index */
+){
+  sqlite3 *db = pParse->db;
+  assert( db->nDb>iDb );
+  pFix->pParse = pParse;
+  pFix->zDb = db->aDb[iDb].zDbSName;
+  pFix->pSchema = db->aDb[iDb].pSchema;
+  pFix->zType = zType;
+  pFix->pName = pName;
+  pFix->bTemp = (iDb==1);
+  pFix->w.pParse = pParse;
+  pFix->w.xExprCallback = fixExprCb;
+  pFix->w.xSelectCallback = fixSelectCb;
+  pFix->w.xSelectCallback2 = sqlite3WalkWinDefnDummyCallback;
+  pFix->w.walkerDepth = 0;
+  pFix->w.eCode = 0;
+  pFix->w.u.pFix = pFix;
+}
+
+/*
+** The following set of routines walk through the parse tree and assign
+** a specific database to all table references where the database name
+** was left unspecified in the original SQL statement.  The pFix structure
+** must have been initialized by a prior call to sqlite3FixInit().
+**
+** These routines are used to make sure that an index, trigger, or
+** view in one database does not refer to objects in a different database.
+** (Exception: indices, triggers, and views in the TEMP database are
+** allowed to refer to anything.)  If a reference is explicitly made
+** to an object in a different database, an error message is added to
+** pParse->zErrMsg and these routines return non-zero.  If everything
+** checks out, these routines return 0.
+*/
+SQLITE_PRIVATE int sqlite3FixSrcList(
+  DbFixer *pFix,       /* Context of the fixation */
+  SrcList *pList       /* The Source list to check and modify */
+){
+  int res = 0;
+  if( pList ){
+    Select s;
+    memset(&s, 0, sizeof(s));
+    s.pSrc = pList;
+    res = sqlite3WalkSelect(&pFix->w, &s);
+  }
+  return res;
+}
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
+SQLITE_PRIVATE int sqlite3FixSelect(
+  DbFixer *pFix,       /* Context of the fixation */
+  Select *pSelect      /* The SELECT statement to be fixed to one database */
+){
+  return sqlite3WalkSelect(&pFix->w, pSelect);
+}
+SQLITE_PRIVATE int sqlite3FixExpr(
+  DbFixer *pFix,     /* Context of the fixation */
+  Expr *pExpr        /* The expression to be fixed to one database */
+){
+  return sqlite3WalkExpr(&pFix->w, pExpr);
+}
+#endif
+
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE int sqlite3FixTriggerStep(
+  DbFixer *pFix,     /* Context of the fixation */
+  TriggerStep *pStep /* The trigger step be fixed to one database */
+){
+  while( pStep ){
+    if( sqlite3WalkSelect(&pFix->w, pStep->pSelect)
+     || sqlite3WalkExpr(&pFix->w, pStep->pWhere)
+     || sqlite3WalkExprList(&pFix->w, pStep->pExprList)
+     || sqlite3FixSrcList(pFix, pStep->pFrom)
+    ){
+      return 1;
+    }
+#ifndef SQLITE_OMIT_UPSERT
+    {
+      Upsert *pUp;
+      for(pUp=pStep->pUpsert; pUp; pUp=pUp->pNextUpsert){
+        if( sqlite3WalkExprList(&pFix->w, pUp->pUpsertTarget)
+         || sqlite3WalkExpr(&pFix->w, pUp->pUpsertTargetWhere)
+         || sqlite3WalkExprList(&pFix->w, pUp->pUpsertSet)
+         || sqlite3WalkExpr(&pFix->w, pUp->pUpsertWhere)
+        ){
+          return 1;
+        }
+      }
+    }
+#endif
+    pStep = pStep->pNext;
+  }
+
+  return 0;
+}
+#endif
+
+/************** End of attach.c **********************************************/
+/************** Begin file auth.c ********************************************/
+/*
+** 2003 January 11
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the sqlite3_set_authorizer()
+** API.  This facility is an optional feature of the library.  Embedded
+** systems that do not need this facility may omit it by recompiling
+** the library with -DSQLITE_OMIT_AUTHORIZATION=1
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** All of the code in this file may be omitted by defining a single
+** macro.
+*/
+#ifndef SQLITE_OMIT_AUTHORIZATION
+
+/*
+** Set or clear the access authorization function.
+**
+** The access authorization function is be called during the compilation
+** phase to verify that the user has read and/or write access permission on
+** various fields of the database.  The first argument to the auth function
+** is a copy of the 3rd argument to this routine.  The second argument
+** to the auth function is one of these constants:
+**
+**       SQLITE_CREATE_INDEX
+**       SQLITE_CREATE_TABLE
+**       SQLITE_CREATE_TEMP_INDEX
+**       SQLITE_CREATE_TEMP_TABLE
+**       SQLITE_CREATE_TEMP_TRIGGER
+**       SQLITE_CREATE_TEMP_VIEW
+**       SQLITE_CREATE_TRIGGER
+**       SQLITE_CREATE_VIEW
+**       SQLITE_DELETE
+**       SQLITE_DROP_INDEX
+**       SQLITE_DROP_TABLE
+**       SQLITE_DROP_TEMP_INDEX
+**       SQLITE_DROP_TEMP_TABLE
+**       SQLITE_DROP_TEMP_TRIGGER
+**       SQLITE_DROP_TEMP_VIEW
+**       SQLITE_DROP_TRIGGER
+**       SQLITE_DROP_VIEW
+**       SQLITE_INSERT
+**       SQLITE_PRAGMA
+**       SQLITE_READ
+**       SQLITE_SELECT
+**       SQLITE_TRANSACTION
+**       SQLITE_UPDATE
+**
+** The third and fourth arguments to the auth function are the name of
+** the table and the column that are being accessed.  The auth function
+** should return either SQLITE_OK, SQLITE_DENY, or SQLITE_IGNORE.  If
+** SQLITE_OK is returned, it means that access is allowed.  SQLITE_DENY
+** means that the SQL statement will never-run - the sqlite3_exec() call
+** will return with an error.  SQLITE_IGNORE means that the SQL statement
+** should run but attempts to read the specified column will return NULL
+** and attempts to write the column will be ignored.
+**
+** Setting the auth function to NULL disables this hook.  The default
+** setting of the auth function is NULL.
+*/
+SQLITE_API int sqlite3_set_authorizer(
+  sqlite3 *db,
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
+  void *pArg
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->xAuth = (sqlite3_xauth)xAuth;
+  db->pAuthArg = pArg;
+  if( db->xAuth ) sqlite3ExpirePreparedStatements(db, 1);
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Write an error message into pParse->zErrMsg that explains that the
+** user-supplied authorization function returned an illegal value.
+*/
+static void sqliteAuthBadReturnCode(Parse *pParse){
+  sqlite3ErrorMsg(pParse, "authorizer malfunction");
+  pParse->rc = SQLITE_ERROR;
+}
+
+/*
+** Invoke the authorization callback for permission to read column zCol from
+** table zTab in database zDb. This function assumes that an authorization
+** callback has been registered (i.e. that sqlite3.xAuth is not NULL).
+**
+** If SQLITE_IGNORE is returned and pExpr is not NULL, then pExpr is changed
+** to an SQL NULL expression. Otherwise, if pExpr is NULL, then SQLITE_IGNORE
+** is treated as SQLITE_DENY. In this case an error is left in pParse.
+*/
+SQLITE_PRIVATE int sqlite3AuthReadCol(
+  Parse *pParse,                  /* The parser context */
+  const char *zTab,               /* Table name */
+  const char *zCol,               /* Column name */
+  int iDb                         /* Index of containing database. */
+){
+  sqlite3 *db = pParse->db;          /* Database handle */
+  char *zDb = db->aDb[iDb].zDbSName; /* Schema name of attached database */
+  int rc;                            /* Auth callback return code */
+
+  if( db->init.busy ) return SQLITE_OK;
+  rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext);
+  if( rc==SQLITE_DENY ){
+    char *z = sqlite3_mprintf("%s.%s", zTab, zCol);
+    if( db->nDb>2 || iDb!=0 ) z = sqlite3_mprintf("%s.%z", zDb, z);
+    sqlite3ErrorMsg(pParse, "access to %z is prohibited", z);
+    pParse->rc = SQLITE_AUTH;
+  }else if( rc!=SQLITE_IGNORE && rc!=SQLITE_OK ){
+    sqliteAuthBadReturnCode(pParse);
+  }
+  return rc;
+}
+
+/*
+** The pExpr should be a TK_COLUMN expression.  The table referred to
+** is in pTabList or else it is the NEW or OLD table of a trigger.
+** Check to see if it is OK to read this particular column.
+**
+** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN
+** instruction into a TK_NULL.  If the auth function returns SQLITE_DENY,
+** then generate an error.
+*/
+SQLITE_PRIVATE void sqlite3AuthRead(
+  Parse *pParse,        /* The parser context */
+  Expr *pExpr,          /* The expression to check authorization on */
+  Schema *pSchema,      /* The schema of the expression */
+  SrcList *pTabList     /* All table that pExpr might refer to */
+){
+  Table *pTab = 0;      /* The table being read */
+  const char *zCol;     /* Name of the column of the table */
+  int iSrc;             /* Index in pTabList->a[] of table being read */
+  int iDb;              /* The index of the database the expression refers to */
+  int iCol;             /* Index of column in table */
+
+  assert( pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER );
+  assert( !IN_RENAME_OBJECT );
+  assert( pParse->db->xAuth!=0 );
+  iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
+  if( iDb<0 ){
+    /* An attempt to read a column out of a subquery or other
+    ** temporary table. */
+    return;
+  }
+
+  if( pExpr->op==TK_TRIGGER ){
+    pTab = pParse->pTriggerTab;
+  }else{
+    assert( pTabList );
+    for(iSrc=0; iSrc<pTabList->nSrc; iSrc++){
+      if( pExpr->iTable==pTabList->a[iSrc].iCursor ){
+        pTab = pTabList->a[iSrc].pSTab;
+        break;
+      }
+    }
+  }
+  iCol = pExpr->iColumn;
+  if( pTab==0 ) return;
+
+  if( iCol>=0 ){
+    assert( iCol<pTab->nCol );
+    zCol = pTab->aCol[iCol].zCnName;
+  }else if( pTab->iPKey>=0 ){
+    assert( pTab->iPKey<pTab->nCol );
+    zCol = pTab->aCol[pTab->iPKey].zCnName;
+  }else{
+    zCol = "ROWID";
+  }
+  assert( iDb>=0 && iDb<pParse->db->nDb );
+  if( SQLITE_IGNORE==sqlite3AuthReadCol(pParse, pTab->zName, zCol, iDb) ){
+    pExpr->op = TK_NULL;
+  }
+}
+
+/*
+** Do an authorization check using the code and arguments given.  Return
+** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY.  If SQLITE_DENY
+** is returned, then the error count and error message in pParse are
+** modified appropriately.
+*/
+SQLITE_PRIVATE int sqlite3AuthCheck(
+  Parse *pParse,
+  int code,
+  const char *zArg1,
+  const char *zArg2,
+  const char *zArg3
+){
+  sqlite3 *db = pParse->db;
+  int rc;
+
+  /* Don't do any authorization checks if the database is initializing
+  ** or if the parser is being invoked from within sqlite3_declare_vtab.
+  */
+  assert( !IN_RENAME_OBJECT || db->xAuth==0 );
+  if( db->xAuth==0 || db->init.busy || IN_SPECIAL_PARSE ){
+    return SQLITE_OK;
+  }
+
+  /* EVIDENCE-OF: R-43249-19882 The third through sixth parameters to the
+  ** callback are either NULL pointers or zero-terminated strings that
+  ** contain additional details about the action to be authorized.
+  **
+  ** The following testcase() macros show that any of the 3rd through 6th
+  ** parameters can be either NULL or a string. */
+  testcase( zArg1==0 );
+  testcase( zArg2==0 );
+  testcase( zArg3==0 );
+  testcase( pParse->zAuthContext==0 );
+
+  rc = db->xAuth(db->pAuthArg,code,zArg1,zArg2,zArg3,pParse->zAuthContext);
+  if( rc==SQLITE_DENY ){
+    sqlite3ErrorMsg(pParse, "not authorized");
+    pParse->rc = SQLITE_AUTH;
+  }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
+    rc = SQLITE_DENY;
+    sqliteAuthBadReturnCode(pParse);
+  }
+  return rc;
+}
+
+/*
+** Push an authorization context.  After this routine is called, the
+** zArg3 argument to authorization callbacks will be zContext until
+** popped.  Or if pParse==0, this routine is a no-op.
+*/
+SQLITE_PRIVATE void sqlite3AuthContextPush(
+  Parse *pParse,
+  AuthContext *pContext,
+  const char *zContext
+){
+  assert( pParse );
+  pContext->pParse = pParse;
+  pContext->zAuthContext = pParse->zAuthContext;
+  pParse->zAuthContext = zContext;
+}
+
+/*
+** Pop an authorization context that was previously pushed
+** by sqlite3AuthContextPush
+*/
+SQLITE_PRIVATE void sqlite3AuthContextPop(AuthContext *pContext){
+  if( pContext->pParse ){
+    pContext->pParse->zAuthContext = pContext->zAuthContext;
+    pContext->pParse = 0;
+  }
+}
+
+#endif /* SQLITE_OMIT_AUTHORIZATION */
+
+/************** End of auth.c ************************************************/
+/************** Begin file build.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the SQLite parser
+** when syntax rules are reduced.  The routines in this file handle the
+** following kinds of SQL syntax:
+**
+**     CREATE TABLE
+**     DROP TABLE
+**     CREATE INDEX
+**     DROP INDEX
+**     creating ID lists
+**     BEGIN TRANSACTION
+**     COMMIT
+**     ROLLBACK
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** The TableLock structure is only used by the sqlite3TableLock() and
+** codeTableLocks() functions.
+*/
+struct TableLock {
+  int iDb;               /* The database containing the table to be locked */
+  Pgno iTab;             /* The root page of the table to be locked */
+  u8 isWriteLock;        /* True for write lock.  False for a read lock */
+  const char *zLockName; /* Name of the table */
+};
+
+/*
+** Record the fact that we want to lock a table at run-time.
+**
+** The table to be locked has root page iTab and is found in database iDb.
+** A read or a write lock can be taken depending on isWritelock.
+**
+** This routine just records the fact that the lock is desired.  The
+** code to make the lock occur is generated by a later call to
+** codeTableLocks() which occurs during sqlite3FinishCoding().
+*/
+static SQLITE_NOINLINE void lockTable(
+  Parse *pParse,     /* Parsing context */
+  int iDb,           /* Index of the database containing the table to lock */
+  Pgno iTab,         /* Root page number of the table to be locked */
+  u8 isWriteLock,    /* True for a write lock */
+  const char *zName  /* Name of the table to be locked */
+){
+  Parse *pToplevel;
+  int i;
+  int nBytes;
+  TableLock *p;
+  assert( iDb>=0 );
+
+  pToplevel = sqlite3ParseToplevel(pParse);
+  for(i=0; i<pToplevel->nTableLock; i++){
+    p = &pToplevel->aTableLock[i];
+    if( p->iDb==iDb && p->iTab==iTab ){
+      p->isWriteLock = (p->isWriteLock || isWriteLock);
+      return;
+    }
+  }
+
+  nBytes = sizeof(TableLock) * (pToplevel->nTableLock+1);
+  pToplevel->aTableLock =
+      sqlite3DbReallocOrFree(pToplevel->db, pToplevel->aTableLock, nBytes);
+  if( pToplevel->aTableLock ){
+    p = &pToplevel->aTableLock[pToplevel->nTableLock++];
+    p->iDb = iDb;
+    p->iTab = iTab;
+    p->isWriteLock = isWriteLock;
+    p->zLockName = zName;
+  }else{
+    pToplevel->nTableLock = 0;
+    sqlite3OomFault(pToplevel->db);
+  }
+}
+SQLITE_PRIVATE void sqlite3TableLock(
+  Parse *pParse,     /* Parsing context */
+  int iDb,           /* Index of the database containing the table to lock */
+  Pgno iTab,         /* Root page number of the table to be locked */
+  u8 isWriteLock,    /* True for a write lock */
+  const char *zName  /* Name of the table to be locked */
+){
+  if( iDb==1 ) return;
+  if( !sqlite3BtreeSharable(pParse->db->aDb[iDb].pBt) ) return;
+  lockTable(pParse, iDb, iTab, isWriteLock, zName);
+}
+
+/*
+** Code an OP_TableLock instruction for each table locked by the
+** statement (configured by calls to sqlite3TableLock()).
+*/
+static void codeTableLocks(Parse *pParse){
+  int i;
+  Vdbe *pVdbe = pParse->pVdbe;
+  assert( pVdbe!=0 );
+
+  for(i=0; i<pParse->nTableLock; i++){
+    TableLock *p = &pParse->aTableLock[i];
+    int p1 = p->iDb;
+    sqlite3VdbeAddOp4(pVdbe, OP_TableLock, p1, p->iTab, p->isWriteLock,
+                      p->zLockName, P4_STATIC);
+  }
+}
+#else
+  #define codeTableLocks(x)
+#endif
+
+/*
+** Return TRUE if the given yDbMask object is empty - if it contains no
+** 1 bits.  This routine is used by the DbMaskAllZero() and DbMaskNotZero()
+** macros when SQLITE_MAX_ATTACHED is greater than 30.
+*/
+#if SQLITE_MAX_ATTACHED>30
+SQLITE_PRIVATE int sqlite3DbMaskAllZero(yDbMask m){
+  int i;
+  for(i=0; i<sizeof(yDbMask); i++) if( m[i] ) return 0;
+  return 1;
+}
+#endif
+
+/*
+** This routine is called after a single SQL statement has been
+** parsed and a VDBE program to execute that statement has been
+** prepared.  This routine puts the finishing touches on the
+** VDBE program and resets the pParse structure for the next
+** parse.
+**
+** Note that if an error occurred, it might be the case that
+** no VDBE code was generated.
+*/
+SQLITE_PRIVATE void sqlite3FinishCoding(Parse *pParse){
+  sqlite3 *db;
+  Vdbe *v;
+  int iDb, i;
+
+  assert( pParse->pToplevel==0 );
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nested ) return;
+  if( pParse->nErr ){
+    if( db->mallocFailed ) pParse->rc = SQLITE_NOMEM;
+    return;
+  }
+  assert( db->mallocFailed==0 );
+
+  /* Begin by generating some termination code at the end of the
+  ** vdbe program
+  */
+  v = pParse->pVdbe;
+  if( v==0 ){
+    if( db->init.busy ){
+      pParse->rc = SQLITE_DONE;
+      return;
+    }
+    v = sqlite3GetVdbe(pParse);
+    if( v==0 ) pParse->rc = SQLITE_ERROR;
+  }
+  assert( !pParse->isMultiWrite
+       || sqlite3VdbeAssertMayAbort(v, pParse->mayAbort));
+  if( v ){
+    if( pParse->bReturning ){
+      Returning *pReturning = pParse->u1.pReturning;
+      int addrRewind;
+      int reg;
+
+      if( pReturning->nRetCol ){
+        sqlite3VdbeAddOp0(v, OP_FkCheck);
+        addrRewind =
+           sqlite3VdbeAddOp1(v, OP_Rewind, pReturning->iRetCur);
+        VdbeCoverage(v);
+        reg = pReturning->iRetReg;
+        for(i=0; i<pReturning->nRetCol; i++){
+          sqlite3VdbeAddOp3(v, OP_Column, pReturning->iRetCur, i, reg+i);
+        }
+        sqlite3VdbeAddOp2(v, OP_ResultRow, reg, i);
+        sqlite3VdbeAddOp2(v, OP_Next, pReturning->iRetCur, addrRewind+1);
+        VdbeCoverage(v);
+        sqlite3VdbeJumpHere(v, addrRewind);
+      }
+    }
+    sqlite3VdbeAddOp0(v, OP_Halt);
+
+    /* The cookie mask contains one bit for each database file open.
+    ** (Bit 0 is for main, bit 1 is for temp, and so forth.)  Bits are
+    ** set for each database that is used.  Generate code to start a
+    ** transaction on each used database and to verify the schema cookie
+    ** on each used database.
+    */
+    assert( pParse->nErr>0 || sqlite3VdbeGetOp(v, 0)->opcode==OP_Init );
+    sqlite3VdbeJumpHere(v, 0);
+    assert( db->nDb>0 );
+    iDb = 0;
+    do{
+      Schema *pSchema;
+      if( DbMaskTest(pParse->cookieMask, iDb)==0 ) continue;
+      sqlite3VdbeUsesBtree(v, iDb);
+      pSchema = db->aDb[iDb].pSchema;
+      sqlite3VdbeAddOp4Int(v,
+        OP_Transaction,                    /* Opcode */
+        iDb,                               /* P1 */
+        DbMaskTest(pParse->writeMask,iDb), /* P2 */
+        pSchema->schema_cookie,            /* P3 */
+        pSchema->iGeneration               /* P4 */
+      );
+      if( db->init.busy==0 ) sqlite3VdbeChangeP5(v, 1);
+      VdbeComment((v,
+            "usesStmtJournal=%d", pParse->mayAbort && pParse->isMultiWrite));
+    }while( ++iDb<db->nDb );
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    for(i=0; i<pParse->nVtabLock; i++){
+      char *vtab = (char *)sqlite3GetVTable(db, pParse->apVtabLock[i]);
+      sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
+    }
+    pParse->nVtabLock = 0;
+#endif
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+    /* Once all the cookies have been verified and transactions opened,
+    ** obtain the required table-locks. This is a no-op unless the
+    ** shared-cache feature is enabled.
+    */
+    if( pParse->nTableLock ) codeTableLocks(pParse);
+#endif
+
+    /* Initialize any AUTOINCREMENT data structures required.
+    */
+    if( pParse->pAinc ) sqlite3AutoincrementBegin(pParse);
+
+    /* Code constant expressions that were factored out of inner loops.
+    */
+    if( pParse->pConstExpr ){
+      ExprList *pEL = pParse->pConstExpr;
+      pParse->okConstFactor = 0;
+      for(i=0; i<pEL->nExpr; i++){
+        assert( pEL->a[i].u.iConstExprReg>0 );
+        sqlite3ExprCode(pParse, pEL->a[i].pExpr, pEL->a[i].u.iConstExprReg);
+      }
+    }
+
+    if( pParse->bReturning ){
+      Returning *pRet = pParse->u1.pReturning;
+      if( pRet->nRetCol ){
+        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRet->iRetCur, pRet->nRetCol);
+      }
+    }
+
+    /* Finally, jump back to the beginning of the executable code. */
+    sqlite3VdbeGoto(v, 1);
+  }
+
+  /* Get the VDBE program ready for execution
+  */
+  assert( v!=0 || pParse->nErr );
+  assert( db->mallocFailed==0 || pParse->nErr );
+  if( pParse->nErr==0 ){
+    /* A minimum of one cursor is required if autoincrement is used
+    *  See ticket [a696379c1f08866] */
+    assert( pParse->pAinc==0 || pParse->nTab>0 );
+    sqlite3VdbeMakeReady(v, pParse);
+    pParse->rc = SQLITE_DONE;
+  }else{
+    pParse->rc = SQLITE_ERROR;
+  }
+}
+
+/*
+** Run the parser and code generator recursively in order to generate
+** code for the SQL statement given onto the end of the pParse context
+** currently under construction.  Notes:
+**
+**   *  The final OP_Halt is not appended and other initialization
+**      and finalization steps are omitted because those are handling by the
+**      outermost parser.
+**
+**   *  Built-in SQL functions always take precedence over application-defined
+**      SQL functions.  In other words, it is not possible to override a
+**      built-in function.
+*/
+SQLITE_PRIVATE void sqlite3NestedParse(Parse *pParse, const char *zFormat, ...){
+  va_list ap;
+  char *zSql;
+  sqlite3 *db = pParse->db;
+  u32 savedDbFlags = db->mDbFlags;
+  char saveBuf[PARSE_TAIL_SZ];
+
+  if( pParse->nErr ) return;
+  if( pParse->eParseMode ) return;
+  assert( pParse->nested<10 );  /* Nesting should only be of limited depth */
+  va_start(ap, zFormat);
+  zSql = sqlite3VMPrintf(db, zFormat, ap);
+  va_end(ap);
+  if( zSql==0 ){
+    /* This can result either from an OOM or because the formatted string
+    ** exceeds SQLITE_LIMIT_LENGTH.  In the latter case, we need to set
+    ** an error */
+    if( !db->mallocFailed ) pParse->rc = SQLITE_TOOBIG;
+    pParse->nErr++;
+    return;
+  }
+  pParse->nested++;
+  memcpy(saveBuf, PARSE_TAIL(pParse), PARSE_TAIL_SZ);
+  memset(PARSE_TAIL(pParse), 0, PARSE_TAIL_SZ);
+  db->mDbFlags |= DBFLAG_PreferBuiltin;
+  sqlite3RunParser(pParse, zSql);
+  db->mDbFlags = savedDbFlags;
+  sqlite3DbFree(db, zSql);
+  memcpy(PARSE_TAIL(pParse), saveBuf, PARSE_TAIL_SZ);
+  pParse->nested--;
+}
+
+/*
+** Locate the in-memory structure that describes a particular database
+** table given the name of that table and (optionally) the name of the
+** database containing the table.  Return NULL if not found.
+**
+** If zDatabase is 0, all databases are searched for the table and the
+** first matching table is returned.  (No checking for duplicate table
+** names is done.)  The search order is TEMP first, then MAIN, then any
+** auxiliary databases added using the ATTACH command.
+**
+** See also sqlite3LocateTable().
+*/
+SQLITE_PRIVATE Table *sqlite3FindTable(sqlite3 *db, const char *zName, const char *zDatabase){
+  Table *p = 0;
+  int i;
+
+  /* All mutexes are required for schema access.  Make sure we hold them. */
+  assert( zDatabase!=0 || sqlite3BtreeHoldsAllMutexes(db) );
+  if( zDatabase ){
+    for(i=0; i<db->nDb; i++){
+      if( sqlite3StrICmp(zDatabase, db->aDb[i].zDbSName)==0 ) break;
+    }
+    if( i>=db->nDb ){
+      /* No match against the official names.  But always match "main"
+      ** to schema 0 as a legacy fallback. */
+      if( sqlite3StrICmp(zDatabase,"main")==0 ){
+        i = 0;
+      }else{
+        return 0;
+      }
+    }
+    p = sqlite3HashFind(&db->aDb[i].pSchema->tblHash, zName);
+    if( p==0 && sqlite3StrNICmp(zName, "sqlite_", 7)==0 ){
+      if( i==1 ){
+        if( sqlite3StrICmp(zName+7, &PREFERRED_TEMP_SCHEMA_TABLE[7])==0
+         || sqlite3StrICmp(zName+7, &PREFERRED_SCHEMA_TABLE[7])==0
+         || sqlite3StrICmp(zName+7, &LEGACY_SCHEMA_TABLE[7])==0
+        ){
+          p = sqlite3HashFind(&db->aDb[1].pSchema->tblHash,
+                              LEGACY_TEMP_SCHEMA_TABLE);
+        }
+      }else{
+        if( sqlite3StrICmp(zName+7, &PREFERRED_SCHEMA_TABLE[7])==0 ){
+          p = sqlite3HashFind(&db->aDb[i].pSchema->tblHash,
+                              LEGACY_SCHEMA_TABLE);
+        }
+      }
+    }
+  }else{
+    /* Match against TEMP first */
+    p = sqlite3HashFind(&db->aDb[1].pSchema->tblHash, zName);
+    if( p ) return p;
+    /* The main database is second */
+    p = sqlite3HashFind(&db->aDb[0].pSchema->tblHash, zName);
+    if( p ) return p;
+    /* Attached databases are in order of attachment */
+    for(i=2; i<db->nDb; i++){
+      assert( sqlite3SchemaMutexHeld(db, i, 0) );
+      p = sqlite3HashFind(&db->aDb[i].pSchema->tblHash, zName);
+      if( p ) break;
+    }
+    if( p==0 && sqlite3StrNICmp(zName, "sqlite_", 7)==0 ){
+      if( sqlite3StrICmp(zName+7, &PREFERRED_SCHEMA_TABLE[7])==0 ){
+        p = sqlite3HashFind(&db->aDb[0].pSchema->tblHash, LEGACY_SCHEMA_TABLE);
+      }else if( sqlite3StrICmp(zName+7, &PREFERRED_TEMP_SCHEMA_TABLE[7])==0 ){
+        p = sqlite3HashFind(&db->aDb[1].pSchema->tblHash,
+                            LEGACY_TEMP_SCHEMA_TABLE);
+      }
+    }
+  }
+  return p;
+}
+
+/*
+** Locate the in-memory structure that describes a particular database
+** table given the name of that table and (optionally) the name of the
+** database containing the table.  Return NULL if not found.  Also leave an
+** error message in pParse->zErrMsg.
+**
+** The difference between this routine and sqlite3FindTable() is that this
+** routine leaves an error message in pParse->zErrMsg where
+** sqlite3FindTable() does not.
+*/
+SQLITE_PRIVATE Table *sqlite3LocateTable(
+  Parse *pParse,         /* context in which to report errors */
+  u32 flags,             /* LOCATE_VIEW or LOCATE_NOERR */
+  const char *zName,     /* Name of the table we are looking for */
+  const char *zDbase     /* Name of the database.  Might be NULL */
+){
+  Table *p;
+  sqlite3 *db = pParse->db;
+
+  /* Read the database schema. If an error occurs, leave an error message
+  ** and code in pParse and return NULL. */
+  if( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0
+   && SQLITE_OK!=sqlite3ReadSchema(pParse)
+  ){
+    return 0;
+  }
+
+  p = sqlite3FindTable(db, zName, zDbase);
+  if( p==0 ){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    /* If zName is the not the name of a table in the schema created using
+    ** CREATE, then check to see if it is the name of an virtual table that
+    ** can be an eponymous virtual table. */
+    if( (pParse->prepFlags & SQLITE_PREPARE_NO_VTAB)==0 && db->init.busy==0 ){
+      Module *pMod = (Module*)sqlite3HashFind(&db->aModule, zName);
+      if( pMod==0 && sqlite3_strnicmp(zName, "pragma_", 7)==0 ){
+        pMod = sqlite3PragmaVtabRegister(db, zName);
+      }
+      if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
+        testcase( pMod->pEpoTab==0 );
+        return pMod->pEpoTab;
+      }
+    }
+#endif
+    if( flags & LOCATE_NOERR ) return 0;
+    pParse->checkSchema = 1;
+  }else if( IsVirtual(p) && (pParse->prepFlags & SQLITE_PREPARE_NO_VTAB)!=0 ){
+    p = 0;
+  }
+
+  if( p==0 ){
+    const char *zMsg = flags & LOCATE_VIEW ? "no such view" : "no such table";
+    if( zDbase ){
+      sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
+    }else{
+      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
+    }
+  }else{
+    assert( HasRowid(p) || p->iPKey<0 );
+  }
+
+  return p;
+}
+
+/*
+** Locate the table identified by *p.
+**
+** This is a wrapper around sqlite3LocateTable(). The difference between
+** sqlite3LocateTable() and this function is that this function restricts
+** the search to schema (p->pSchema) if it is not NULL. p->pSchema may be
+** non-NULL if it is part of a view or trigger program definition. See
+** sqlite3FixSrcList() for details.
+*/
+SQLITE_PRIVATE Table *sqlite3LocateTableItem(
+  Parse *pParse,
+  u32 flags,
+  SrcItem *p
+){
+  const char *zDb;
+  if( p->fg.fixedSchema ){
+    int iDb = sqlite3SchemaToIndex(pParse->db, p->u4.pSchema);
+    zDb = pParse->db->aDb[iDb].zDbSName;
+  }else{
+    assert( !p->fg.isSubquery );
+    zDb = p->u4.zDatabase;
+  }
+  return sqlite3LocateTable(pParse, flags, p->zName, zDb);
+}
+
+/*
+** Return the preferred table name for system tables.  Translate legacy
+** names into the new preferred names, as appropriate.
+*/
+SQLITE_PRIVATE const char *sqlite3PreferredTableName(const char *zName){
+  if( sqlite3StrNICmp(zName, "sqlite_", 7)==0 ){
+    if( sqlite3StrICmp(zName+7, &LEGACY_SCHEMA_TABLE[7])==0 ){
+      return PREFERRED_SCHEMA_TABLE;
+    }
+    if( sqlite3StrICmp(zName+7, &LEGACY_TEMP_SCHEMA_TABLE[7])==0 ){
+      return PREFERRED_TEMP_SCHEMA_TABLE;
+    }
+  }
+  return zName;
+}
+
+/*
+** Locate the in-memory structure that describes
+** a particular index given the name of that index
+** and the name of the database that contains the index.
+** Return NULL if not found.
+**
+** If zDatabase is 0, all databases are searched for the
+** table and the first matching index is returned.  (No checking
+** for duplicate index names is done.)  The search order is
+** TEMP first, then MAIN, then any auxiliary databases added
+** using the ATTACH command.
+*/
+SQLITE_PRIVATE Index *sqlite3FindIndex(sqlite3 *db, const char *zName, const char *zDb){
+  Index *p = 0;
+  int i;
+  /* All mutexes are required for schema access.  Make sure we hold them. */
+  assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );
+  for(i=OMIT_TEMPDB; i<db->nDb; i++){
+    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
+    Schema *pSchema = db->aDb[j].pSchema;
+    assert( pSchema );
+    if( zDb && sqlite3DbIsNamed(db, j, zDb)==0 ) continue;
+    assert( sqlite3SchemaMutexHeld(db, j, 0) );
+    p = sqlite3HashFind(&pSchema->idxHash, zName);
+    if( p ) break;
+  }
+  return p;
+}
+
+/*
+** Reclaim the memory used by an index
+*/
+SQLITE_PRIVATE void sqlite3FreeIndex(sqlite3 *db, Index *p){
+#ifndef SQLITE_OMIT_ANALYZE
+  sqlite3DeleteIndexSamples(db, p);
+#endif
+  sqlite3ExprDelete(db, p->pPartIdxWhere);
+  sqlite3ExprListDelete(db, p->aColExpr);
+  sqlite3DbFree(db, p->zColAff);
+  if( p->isResized ) sqlite3DbFree(db, (void *)p->azColl);
+#ifdef SQLITE_ENABLE_STAT4
+  sqlite3_free(p->aiRowEst);
+#endif
+  sqlite3DbFree(db, p);
+}
+
+/*
+** For the index called zIdxName which is found in the database iDb,
+** unlike that index from its Table then remove the index from
+** the index hash table and free all memory structures associated
+** with the index.
+*/
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteIndex(sqlite3 *db, int iDb, const char *zIdxName){
+  Index *pIndex;
+  Hash *pHash;
+
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  pHash = &db->aDb[iDb].pSchema->idxHash;
+  pIndex = sqlite3HashInsert(pHash, zIdxName, 0);
+  if( ALWAYS(pIndex) ){
+    if( pIndex->pTable->pIndex==pIndex ){
+      pIndex->pTable->pIndex = pIndex->pNext;
+    }else{
+      Index *p;
+      /* Justification of ALWAYS();  The index must be on the list of
+      ** indices. */
+      p = pIndex->pTable->pIndex;
+      while( ALWAYS(p) && p->pNext!=pIndex ){ p = p->pNext; }
+      if( ALWAYS(p && p->pNext==pIndex) ){
+        p->pNext = pIndex->pNext;
+      }
+    }
+    sqlite3FreeIndex(db, pIndex);
+  }
+  db->mDbFlags |= DBFLAG_SchemaChange;
+}
+
+/*
+** Look through the list of open database files in db->aDb[] and if
+** any have been closed, remove them from the list.  Reallocate the
+** db->aDb[] structure to a smaller size, if possible.
+**
+** Entry 0 (the "main" database) and entry 1 (the "temp" database)
+** are never candidates for being collapsed.
+*/
+SQLITE_PRIVATE void sqlite3CollapseDatabaseArray(sqlite3 *db){
+  int i, j;
+  for(i=j=2; i<db->nDb; i++){
+    struct Db *pDb = &db->aDb[i];
+    if( pDb->pBt==0 ){
+      sqlite3DbFree(db, pDb->zDbSName);
+      pDb->zDbSName = 0;
+      continue;
+    }
+    if( j<i ){
+      db->aDb[j] = db->aDb[i];
+    }
+    j++;
+  }
+  db->nDb = j;
+  if( db->nDb<=2 && db->aDb!=db->aDbStatic ){
+    memcpy(db->aDbStatic, db->aDb, 2*sizeof(db->aDb[0]));
+    sqlite3DbFree(db, db->aDb);
+    db->aDb = db->aDbStatic;
+  }
+}
+
+/*
+** Reset the schema for the database at index iDb.  Also reset the
+** TEMP schema.  The reset is deferred if db->nSchemaLock is not zero.
+** Deferred resets may be run by calling with iDb<0.
+*/
+SQLITE_PRIVATE void sqlite3ResetOneSchema(sqlite3 *db, int iDb){
+  int i;
+  assert( iDb<db->nDb );
+
+  if( iDb>=0 ){
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    DbSetProperty(db, iDb, DB_ResetWanted);
+    DbSetProperty(db, 1, DB_ResetWanted);
+    db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
+  }
+
+  if( db->nSchemaLock==0 ){
+    for(i=0; i<db->nDb; i++){
+      if( DbHasProperty(db, i, DB_ResetWanted) ){
+        sqlite3SchemaClear(db->aDb[i].pSchema);
+      }
+    }
+  }
+}
+
+/*
+** Erase all schema information from all attached databases (including
+** "main" and "temp") for a single database connection.
+*/
+SQLITE_PRIVATE void sqlite3ResetAllSchemasOfConnection(sqlite3 *db){
+  int i;
+  sqlite3BtreeEnterAll(db);
+  for(i=0; i<db->nDb; i++){
+    Db *pDb = &db->aDb[i];
+    if( pDb->pSchema ){
+      if( db->nSchemaLock==0 ){
+        sqlite3SchemaClear(pDb->pSchema);
+      }else{
+        DbSetProperty(db, i, DB_ResetWanted);
+      }
+    }
+  }
+  db->mDbFlags &= ~(DBFLAG_SchemaChange|DBFLAG_SchemaKnownOk);
+  sqlite3VtabUnlockList(db);
+  sqlite3BtreeLeaveAll(db);
+  if( db->nSchemaLock==0 ){
+    sqlite3CollapseDatabaseArray(db);
+  }
+}
+
+/*
+** This routine is called when a commit occurs.
+*/
+SQLITE_PRIVATE void sqlite3CommitInternalChanges(sqlite3 *db){
+  db->mDbFlags &= ~DBFLAG_SchemaChange;
+}
+
+/*
+** Set the expression associated with a column.  This is usually
+** the DEFAULT value, but might also be the expression that computes
+** the value for a generated column.
+*/
+SQLITE_PRIVATE void sqlite3ColumnSetExpr(
+  Parse *pParse,    /* Parsing context */
+  Table *pTab,      /* The table containing the column */
+  Column *pCol,     /* The column to receive the new DEFAULT expression */
+  Expr *pExpr       /* The new default expression */
+){
+  ExprList *pList;
+  assert( IsOrdinaryTable(pTab) );
+  pList = pTab->u.tab.pDfltList;
+  if( pCol->iDflt==0
+   || NEVER(pList==0)
+   || NEVER(pList->nExpr<pCol->iDflt)
+  ){
+    pCol->iDflt = pList==0 ? 1 : pList->nExpr+1;
+    pTab->u.tab.pDfltList = sqlite3ExprListAppend(pParse, pList, pExpr);
+  }else{
+    sqlite3ExprDelete(pParse->db, pList->a[pCol->iDflt-1].pExpr);
+    pList->a[pCol->iDflt-1].pExpr = pExpr;
+  }
+}
+
+/*
+** Return the expression associated with a column.  The expression might be
+** the DEFAULT clause or the AS clause of a generated column.
+** Return NULL if the column has no associated expression.
+*/
+SQLITE_PRIVATE Expr *sqlite3ColumnExpr(Table *pTab, Column *pCol){
+  if( pCol->iDflt==0 ) return 0;
+  if( !IsOrdinaryTable(pTab) ) return 0;
+  if( NEVER(pTab->u.tab.pDfltList==0) ) return 0;
+  if( NEVER(pTab->u.tab.pDfltList->nExpr<pCol->iDflt) ) return 0;
+  return pTab->u.tab.pDfltList->a[pCol->iDflt-1].pExpr;
+}
+
+/*
+** Set the collating sequence name for a column.
+*/
+SQLITE_PRIVATE void sqlite3ColumnSetColl(
+  sqlite3 *db,
+  Column *pCol,
+  const char *zColl
+){
+  i64 nColl;
+  i64 n;
+  char *zNew;
+  assert( zColl!=0 );
+  n = sqlite3Strlen30(pCol->zCnName) + 1;
+  if( pCol->colFlags & COLFLAG_HASTYPE ){
+    n += sqlite3Strlen30(pCol->zCnName+n) + 1;
+  }
+  nColl = sqlite3Strlen30(zColl) + 1;
+  zNew = sqlite3DbRealloc(db, pCol->zCnName, nColl+n);
+  if( zNew ){
+    pCol->zCnName = zNew;
+    memcpy(pCol->zCnName + n, zColl, nColl);
+    pCol->colFlags |= COLFLAG_HASCOLL;
+  }
+}
+
+/*
+** Return the collating sequence name for a column
+*/
+SQLITE_PRIVATE const char *sqlite3ColumnColl(Column *pCol){
+  const char *z;
+  if( (pCol->colFlags & COLFLAG_HASCOLL)==0 ) return 0;
+  z = pCol->zCnName;
+  while( *z ){ z++; }
+  if( pCol->colFlags & COLFLAG_HASTYPE ){
+    do{ z++; }while( *z );
+  }
+  return z+1;
+}
+
+/*
+** Delete memory allocated for the column names of a table or view (the
+** Table.aCol[] array).
+*/
+SQLITE_PRIVATE void sqlite3DeleteColumnNames(sqlite3 *db, Table *pTable){
+  int i;
+  Column *pCol;
+  assert( pTable!=0 );
+  assert( db!=0 );
+  if( (pCol = pTable->aCol)!=0 ){
+    for(i=0; i<pTable->nCol; i++, pCol++){
+      assert( pCol->zCnName==0 || pCol->hName==sqlite3StrIHash(pCol->zCnName) );
+      sqlite3DbFree(db, pCol->zCnName);
+    }
+    sqlite3DbNNFreeNN(db, pTable->aCol);
+    if( IsOrdinaryTable(pTable) ){
+      sqlite3ExprListDelete(db, pTable->u.tab.pDfltList);
+    }
+    if( db->pnBytesFreed==0 ){
+      pTable->aCol = 0;
+      pTable->nCol = 0;
+      if( IsOrdinaryTable(pTable) ){
+        pTable->u.tab.pDfltList = 0;
+      }
+    }
+  }
+}
+
+/*
+** Remove the memory data structures associated with the given
+** Table.  No changes are made to disk by this routine.
+**
+** This routine just deletes the data structure.  It does not unlink
+** the table data structure from the hash table.  But it does destroy
+** memory structures of the indices and foreign keys associated with
+** the table.
+**
+** The db parameter is optional.  It is needed if the Table object
+** contains lookaside memory.  (Table objects in the schema do not use
+** lookaside memory, but some ephemeral Table objects do.)  Or the
+** db parameter can be used with db->pnBytesFreed to measure the memory
+** used by the Table object.
+*/
+static void SQLITE_NOINLINE deleteTable(sqlite3 *db, Table *pTable){
+  Index *pIndex, *pNext;
+
+#ifdef SQLITE_DEBUG
+  /* Record the number of outstanding lookaside allocations in schema Tables
+  ** prior to doing any free() operations. Since schema Tables do not use
+  ** lookaside, this number should not change.
+  **
+  ** If malloc has already failed, it may be that it failed while allocating
+  ** a Table object that was going to be marked ephemeral. So do not check
+  ** that no lookaside memory is used in this case either. */
+  int nLookaside = 0;
+  assert( db!=0 );
+  if( !db->mallocFailed && (pTable->tabFlags & TF_Ephemeral)==0 ){
+    nLookaside = sqlite3LookasideUsed(db, 0);
+  }
+#endif
+
+  /* Delete all indices associated with this table. */
+  for(pIndex = pTable->pIndex; pIndex; pIndex=pNext){
+    pNext = pIndex->pNext;
+    assert( pIndex->pSchema==pTable->pSchema
+         || (IsVirtual(pTable) && pIndex->idxType!=SQLITE_IDXTYPE_APPDEF) );
+    if( db->pnBytesFreed==0 && !IsVirtual(pTable) ){
+      char *zName = pIndex->zName;
+      TESTONLY ( Index *pOld = ) sqlite3HashInsert(
+         &pIndex->pSchema->idxHash, zName, 0
+      );
+      assert( db==0 || sqlite3SchemaMutexHeld(db, 0, pIndex->pSchema) );
+      assert( pOld==pIndex || pOld==0 );
+    }
+    sqlite3FreeIndex(db, pIndex);
+  }
+
+  if( IsOrdinaryTable(pTable) ){
+    sqlite3FkDelete(db, pTable);
+  }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  else if( IsVirtual(pTable) ){
+    sqlite3VtabClear(db, pTable);
+  }
+#endif
+  else{
+    assert( IsView(pTable) );
+    sqlite3SelectDelete(db, pTable->u.view.pSelect);
+  }
+
+  /* Delete the Table structure itself.
+  */
+  sqlite3DeleteColumnNames(db, pTable);
+  sqlite3DbFree(db, pTable->zName);
+  sqlite3DbFree(db, pTable->zColAff);
+  sqlite3ExprListDelete(db, pTable->pCheck);
+  sqlite3DbFree(db, pTable);
+
+  /* Verify that no lookaside memory was used by schema tables */
+  assert( nLookaside==0 || nLookaside==sqlite3LookasideUsed(db,0) );
+}
+SQLITE_PRIVATE void sqlite3DeleteTable(sqlite3 *db, Table *pTable){
+  /* Do not delete the table until the reference count reaches zero. */
+  assert( db!=0 );
+  if( !pTable ) return;
+  if( db->pnBytesFreed==0 && (--pTable->nTabRef)>0 ) return;
+  deleteTable(db, pTable);
+}
+SQLITE_PRIVATE void sqlite3DeleteTableGeneric(sqlite3 *db, void *pTable){
+  sqlite3DeleteTable(db, (Table*)pTable);
+}
+
+
+/*
+** Unlink the given table from the hash tables and the delete the
+** table structure with all its indices and foreign keys.
+*/
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTable(sqlite3 *db, int iDb, const char *zTabName){
+  Table *p;
+  Db *pDb;
+
+  assert( db!=0 );
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( zTabName );
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  testcase( zTabName[0]==0 );  /* Zero-length table names are allowed */
+  pDb = &db->aDb[iDb];
+  p = sqlite3HashInsert(&pDb->pSchema->tblHash, zTabName, 0);
+  sqlite3DeleteTable(db, p);
+  db->mDbFlags |= DBFLAG_SchemaChange;
+}
+
+/*
+** Given a token, return a string that consists of the text of that
+** token.  Space to hold the returned string
+** is obtained from sqliteMalloc() and must be freed by the calling
+** function.
+**
+** Any quotation marks (ex:  "name", 'name', [name], or `name`) that
+** surround the body of the token are removed.
+**
+** Tokens are often just pointers into the original SQL text and so
+** are not \000 terminated and are not persistent.  The returned string
+** is \000 terminated and is persistent.
+*/
+SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3 *db, const Token *pName){
+  char *zName;
+  if( pName ){
+    zName = sqlite3DbStrNDup(db, (const char*)pName->z, pName->n);
+    sqlite3Dequote(zName);
+  }else{
+    zName = 0;
+  }
+  return zName;
+}
+
+/*
+** Open the sqlite_schema table stored in database number iDb for
+** writing. The table is opened using cursor 0.
+*/
+SQLITE_PRIVATE void sqlite3OpenSchemaTable(Parse *p, int iDb){
+  Vdbe *v = sqlite3GetVdbe(p);
+  sqlite3TableLock(p, iDb, SCHEMA_ROOT, 1, LEGACY_SCHEMA_TABLE);
+  sqlite3VdbeAddOp4Int(v, OP_OpenWrite, 0, SCHEMA_ROOT, iDb, 5);
+  if( p->nTab==0 ){
+    p->nTab = 1;
+  }
+}
+
+/*
+** Parameter zName points to a nul-terminated buffer containing the name
+** of a database ("main", "temp" or the name of an attached db). This
+** function returns the index of the named database in db->aDb[], or
+** -1 if the named db cannot be found.
+*/
+SQLITE_PRIVATE int sqlite3FindDbName(sqlite3 *db, const char *zName){
+  int i = -1;         /* Database number */
+  if( zName ){
+    Db *pDb;
+    for(i=(db->nDb-1), pDb=&db->aDb[i]; i>=0; i--, pDb--){
+      if( 0==sqlite3_stricmp(pDb->zDbSName, zName) ) break;
+      /* "main" is always an acceptable alias for the primary database
+      ** even if it has been renamed using SQLITE_DBCONFIG_MAINDBNAME. */
+      if( i==0 && 0==sqlite3_stricmp("main", zName) ) break;
+    }
+  }
+  return i;
+}
+
+/*
+** The token *pName contains the name of a database (either "main" or
+** "temp" or the name of an attached db). This routine returns the
+** index of the named database in db->aDb[], or -1 if the named db
+** does not exist.
+*/
+SQLITE_PRIVATE int sqlite3FindDb(sqlite3 *db, Token *pName){
+  int i;                               /* Database number */
+  char *zName;                         /* Name we are searching for */
+  zName = sqlite3NameFromToken(db, pName);
+  i = sqlite3FindDbName(db, zName);
+  sqlite3DbFree(db, zName);
+  return i;
+}
+
+/* The table or view or trigger name is passed to this routine via tokens
+** pName1 and pName2. If the table name was fully qualified, for example:
+**
+** CREATE TABLE xxx.yyy (...);
+**
+** Then pName1 is set to "xxx" and pName2 "yyy". On the other hand if
+** the table name is not fully qualified, i.e.:
+**
+** CREATE TABLE yyy(...);
+**
+** Then pName1 is set to "yyy" and pName2 is "".
+**
+** This routine sets the *ppUnqual pointer to point at the token (pName1 or
+** pName2) that stores the unqualified table name.  The index of the
+** database "xxx" is returned.
+*/
+SQLITE_PRIVATE int sqlite3TwoPartName(
+  Parse *pParse,      /* Parsing and code generating context */
+  Token *pName1,      /* The "xxx" in the name "xxx.yyy" or "xxx" */
+  Token *pName2,      /* The "yyy" in the name "xxx.yyy" */
+  Token **pUnqual     /* Write the unqualified object name here */
+){
+  int iDb;                    /* Database holding the object */
+  sqlite3 *db = pParse->db;
+
+  assert( pName2!=0 );
+  if( pName2->n>0 ){
+    if( db->init.busy ) {
+      sqlite3ErrorMsg(pParse, "corrupt database");
+      return -1;
+    }
+    *pUnqual = pName2;
+    iDb = sqlite3FindDb(db, pName1);
+    if( iDb<0 ){
+      sqlite3ErrorMsg(pParse, "unknown database %T", pName1);
+      return -1;
+    }
+  }else{
+    assert( db->init.iDb==0 || db->init.busy || IN_SPECIAL_PARSE
+             || (db->mDbFlags & DBFLAG_Vacuum)!=0);
+    iDb = db->init.iDb;
+    *pUnqual = pName1;
+  }
+  return iDb;
+}
+
+/*
+** True if PRAGMA writable_schema is ON
+*/
+SQLITE_PRIVATE int sqlite3WritableSchema(sqlite3 *db){
+  testcase( (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==0 );
+  testcase( (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==
+               SQLITE_WriteSchema );
+  testcase( (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==
+               SQLITE_Defensive );
+  testcase( (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==
+               (SQLITE_WriteSchema|SQLITE_Defensive) );
+  return (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==SQLITE_WriteSchema;
+}
+
+/*
+** This routine is used to check if the UTF-8 string zName is a legal
+** unqualified name for a new schema object (table, index, view or
+** trigger). All names are legal except those that begin with the string
+** "sqlite_" (in upper, lower or mixed case). This portion of the namespace
+** is reserved for internal use.
+**
+** When parsing the sqlite_schema table, this routine also checks to
+** make sure the "type", "name", and "tbl_name" columns are consistent
+** with the SQL.
+*/
+SQLITE_PRIVATE int sqlite3CheckObjectName(
+  Parse *pParse,            /* Parsing context */
+  const char *zName,        /* Name of the object to check */
+  const char *zType,        /* Type of this object */
+  const char *zTblName      /* Parent table name for triggers and indexes */
+){
+  sqlite3 *db = pParse->db;
+  if( sqlite3WritableSchema(db)
+   || db->init.imposterTable
+   || !sqlite3Config.bExtraSchemaChecks
+  ){
+    /* Skip these error checks for writable_schema=ON */
+    return SQLITE_OK;
+  }
+  if( db->init.busy ){
+    if( sqlite3_stricmp(zType, db->init.azInit[0])
+     || sqlite3_stricmp(zName, db->init.azInit[1])
+     || sqlite3_stricmp(zTblName, db->init.azInit[2])
+    ){
+      sqlite3ErrorMsg(pParse, ""); /* corruptSchema() will supply the error */
+      return SQLITE_ERROR;
+    }
+  }else{
+    if( (pParse->nested==0 && 0==sqlite3StrNICmp(zName, "sqlite_", 7))
+     || (sqlite3ReadOnlyShadowTables(db) && sqlite3ShadowTableName(db, zName))
+    ){
+      sqlite3ErrorMsg(pParse, "object name reserved for internal use: %s",
+                      zName);
+      return SQLITE_ERROR;
+    }
+
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return the PRIMARY KEY index of a table
+*/
+SQLITE_PRIVATE Index *sqlite3PrimaryKeyIndex(Table *pTab){
+  Index *p;
+  for(p=pTab->pIndex; p && !IsPrimaryKeyIndex(p); p=p->pNext){}
+  return p;
+}
+
+/*
+** Convert an table column number into a index column number.  That is,
+** for the column iCol in the table (as defined by the CREATE TABLE statement)
+** find the (first) offset of that column in index pIdx.  Or return -1
+** if column iCol is not used in index pIdx.
+*/
+SQLITE_PRIVATE i16 sqlite3TableColumnToIndex(Index *pIdx, i16 iCol){
+  int i;
+  for(i=0; i<pIdx->nColumn; i++){
+    if( iCol==pIdx->aiColumn[i] ) return i;
+  }
+  return -1;
+}
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+/* Convert a storage column number into a table column number.
+**
+** The storage column number (0,1,2,....) is the index of the value
+** as it appears in the record on disk.  The true column number
+** is the index (0,1,2,...) of the column in the CREATE TABLE statement.
+**
+** The storage column number is less than the table column number if
+** and only there are VIRTUAL columns to the left.
+**
+** If SQLITE_OMIT_GENERATED_COLUMNS, this routine is a no-op macro.
+*/
+SQLITE_PRIVATE i16 sqlite3StorageColumnToTable(Table *pTab, i16 iCol){
+  if( pTab->tabFlags & TF_HasVirtual ){
+    int i;
+    for(i=0; i<=iCol; i++){
+      if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ) iCol++;
+    }
+  }
+  return iCol;
+}
+#endif
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+/* Convert a table column number into a storage column number.
+**
+** The storage column number (0,1,2,....) is the index of the value
+** as it appears in the record on disk.  Or, if the input column is
+** the N-th virtual column (zero-based) then the storage number is
+** the number of non-virtual columns in the table plus N.
+**
+** The true column number is the index (0,1,2,...) of the column in
+** the CREATE TABLE statement.
+**
+** If the input column is a VIRTUAL column, then it should not appear
+** in storage.  But the value sometimes is cached in registers that
+** follow the range of registers used to construct storage.  This
+** avoids computing the same VIRTUAL column multiple times, and provides
+** values for use by OP_Param opcodes in triggers.  Hence, if the
+** input column is a VIRTUAL table, put it after all the other columns.
+**
+** In the following, N means "normal column", S means STORED, and
+** V means VIRTUAL.  Suppose the CREATE TABLE has columns like this:
+**
+**        CREATE TABLE ex(N,S,V,N,S,V,N,S,V);
+**                     -- 0 1 2 3 4 5 6 7 8
+**
+** Then the mapping from this function is as follows:
+**
+**    INPUTS:     0 1 2 3 4 5 6 7 8
+**    OUTPUTS:    0 1 6 2 3 7 4 5 8
+**
+** So, in other words, this routine shifts all the virtual columns to
+** the end.
+**
+** If SQLITE_OMIT_GENERATED_COLUMNS then there are no virtual columns and
+** this routine is a no-op macro.  If the pTab does not have any virtual
+** columns, then this routine is no-op that always return iCol.  If iCol
+** is negative (indicating the ROWID column) then this routine return iCol.
+*/
+SQLITE_PRIVATE i16 sqlite3TableColumnToStorage(Table *pTab, i16 iCol){
+  int i;
+  i16 n;
+  assert( iCol<pTab->nCol );
+  if( (pTab->tabFlags & TF_HasVirtual)==0 || iCol<0 ) return iCol;
+  for(i=0, n=0; i<iCol; i++){
+    if( (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0 ) n++;
+  }
+  if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ){
+    /* iCol is a virtual column itself */
+    return pTab->nNVCol + i - n;
+  }else{
+    /* iCol is a normal or stored column */
+    return n;
+  }
+}
+#endif
+
+/*
+** Insert a single OP_JournalMode query opcode in order to force the
+** prepared statement to return false for sqlite3_stmt_readonly().  This
+** is used by CREATE TABLE IF NOT EXISTS and similar if the table already
+** exists, so that the prepared statement for CREATE TABLE IF NOT EXISTS
+** will return false for sqlite3_stmt_readonly() even if that statement
+** is a read-only no-op.
+*/
+static void sqlite3ForceNotReadOnly(Parse *pParse){
+  int iReg = ++pParse->nMem;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp3(v, OP_JournalMode, 0, iReg, PAGER_JOURNALMODE_QUERY);
+    sqlite3VdbeUsesBtree(v, 0);
+  }
+}
+
+/*
+** Begin constructing a new table representation in memory.  This is
+** the first of several action routines that get called in response
+** to a CREATE TABLE statement.  In particular, this routine is called
+** after seeing tokens "CREATE" and "TABLE" and the table name. The isTemp
+** flag is true if the table should be stored in the auxiliary database
+** file instead of in the main database file.  This is normally the case
+** when the "TEMP" or "TEMPORARY" keyword occurs in between
+** CREATE and TABLE.
+**
+** The new table record is initialized and put in pParse->pNewTable.
+** As more of the CREATE TABLE statement is parsed, additional action
+** routines will be called to add more information to this record.
+** At the end of the CREATE TABLE statement, the sqlite3EndTable() routine
+** is called to complete the construction of the new table record.
+*/
+SQLITE_PRIVATE void sqlite3StartTable(
+  Parse *pParse,   /* Parser context */
+  Token *pName1,   /* First part of the name of the table or view */
+  Token *pName2,   /* Second part of the name of the table or view */
+  int isTemp,      /* True if this is a TEMP table */
+  int isView,      /* True if this is a VIEW */
+  int isVirtual,   /* True if this is a VIRTUAL table */
+  int noErr        /* Do nothing if table already exists */
+){
+  Table *pTable;
+  char *zName = 0; /* The name of the new table */
+  sqlite3 *db = pParse->db;
+  Vdbe *v;
+  int iDb;         /* Database number to create the table in */
+  Token *pName;    /* Unqualified name of the table to create */
+
+  if( db->init.busy && db->init.newTnum==1 ){
+    /* Special case:  Parsing the sqlite_schema or sqlite_temp_schema schema */
+    iDb = db->init.iDb;
+    zName = sqlite3DbStrDup(db, SCHEMA_TABLE(iDb));
+    pName = pName1;
+  }else{
+    /* The common case */
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+    if( iDb<0 ) return;
+    if( !OMIT_TEMPDB && isTemp && pName2->n>0 && iDb!=1 ){
+      /* If creating a temp table, the name may not be qualified. Unless
+      ** the database name is "temp" anyway.  */
+      sqlite3ErrorMsg(pParse, "temporary table name must be unqualified");
+      return;
+    }
+    if( !OMIT_TEMPDB && isTemp ) iDb = 1;
+    zName = sqlite3NameFromToken(db, pName);
+    if( IN_RENAME_OBJECT ){
+      sqlite3RenameTokenMap(pParse, (void*)zName, pName);
+    }
+  }
+  pParse->sNameToken = *pName;
+  if( zName==0 ) return;
+  if( sqlite3CheckObjectName(pParse, zName, isView?"view":"table", zName) ){
+    goto begin_table_error;
+  }
+  if( db->init.iDb==1 ) isTemp = 1;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  assert( isTemp==0 || isTemp==1 );
+  assert( isView==0 || isView==1 );
+  {
+    static const u8 aCode[] = {
+       SQLITE_CREATE_TABLE,
+       SQLITE_CREATE_TEMP_TABLE,
+       SQLITE_CREATE_VIEW,
+       SQLITE_CREATE_TEMP_VIEW
+    };
+    char *zDb = db->aDb[iDb].zDbSName;
+    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(isTemp), 0, zDb) ){
+      goto begin_table_error;
+    }
+    if( !isVirtual && sqlite3AuthCheck(pParse, (int)aCode[isTemp+2*isView],
+                                       zName, 0, zDb) ){
+      goto begin_table_error;
+    }
+  }
+#endif
+
+  /* Make sure the new table name does not collide with an existing
+  ** index or table name in the same database.  Issue an error message if
+  ** it does. The exception is if the statement being parsed was passed
+  ** to an sqlite3_declare_vtab() call. In that case only the column names
+  ** and types will be used, so there is no need to test for namespace
+  ** collisions.
+  */
+  if( !IN_SPECIAL_PARSE ){
+    char *zDb = db->aDb[iDb].zDbSName;
+    if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+      goto begin_table_error;
+    }
+    pTable = sqlite3FindTable(db, zName, zDb);
+    if( pTable ){
+      if( !noErr ){
+        sqlite3ErrorMsg(pParse, "%s %T already exists",
+                        (IsView(pTable)? "view" : "table"), pName);
+      }else{
+        assert( !db->init.busy || CORRUPT_DB );
+        sqlite3CodeVerifySchema(pParse, iDb);
+        sqlite3ForceNotReadOnly(pParse);
+      }
+      goto begin_table_error;
+    }
+    if( sqlite3FindIndex(db, zName, zDb)!=0 ){
+      sqlite3ErrorMsg(pParse, "there is already an index named %s", zName);
+      goto begin_table_error;
+    }
+  }
+
+  pTable = sqlite3DbMallocZero(db, sizeof(Table));
+  if( pTable==0 ){
+    assert( db->mallocFailed );
+    pParse->rc = SQLITE_NOMEM_BKPT;
+    pParse->nErr++;
+    goto begin_table_error;
+  }
+  pTable->zName = zName;
+  pTable->iPKey = -1;
+  pTable->pSchema = db->aDb[iDb].pSchema;
+  pTable->nTabRef = 1;
+#ifdef SQLITE_DEFAULT_ROWEST
+  pTable->nRowLogEst = sqlite3LogEst(SQLITE_DEFAULT_ROWEST);
+#else
+  pTable->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
+#endif
+  assert( pParse->pNewTable==0 );
+  pParse->pNewTable = pTable;
+
+  /* Begin generating the code that will insert the table record into
+  ** the schema table.  Note in particular that we must go ahead
+  ** and allocate the record number for the table entry now.  Before any
+  ** PRIMARY KEY or UNIQUE keywords are parsed.  Those keywords will cause
+  ** indices to be created and the table record must come before the
+  ** indices.  Hence, the record number for the table must be allocated
+  ** now.
+  */
+  if( !db->init.busy && (v = sqlite3GetVdbe(pParse))!=0 ){
+    int addr1;
+    int fileFormat;
+    int reg1, reg2, reg3;
+    /* nullRow[] is an OP_Record encoding of a row containing 5 NULLs */
+    static const char nullRow[] = { 6, 0, 0, 0, 0, 0 };
+    sqlite3BeginWriteOperation(pParse, 1, iDb);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( isVirtual ){
+      sqlite3VdbeAddOp0(v, OP_VBegin);
+    }
+#endif
+
+    /* If the file format and encoding in the database have not been set,
+    ** set them now.
+    */
+    reg1 = pParse->regRowid = ++pParse->nMem;
+    reg2 = pParse->regRoot = ++pParse->nMem;
+    reg3 = ++pParse->nMem;
+    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, reg3, BTREE_FILE_FORMAT);
+    sqlite3VdbeUsesBtree(v, iDb);
+    addr1 = sqlite3VdbeAddOp1(v, OP_If, reg3); VdbeCoverage(v);
+    fileFormat = (db->flags & SQLITE_LegacyFileFmt)!=0 ?
+                  1 : SQLITE_MAX_FILE_FORMAT;
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, fileFormat);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_TEXT_ENCODING, ENC(db));
+    sqlite3VdbeJumpHere(v, addr1);
+
+    /* This just creates a place-holder record in the sqlite_schema table.
+    ** The record created does not contain anything yet.  It will be replaced
+    ** by the real entry in code generated at sqlite3EndTable().
+    **
+    ** The rowid for the new entry is left in register pParse->regRowid.
+    ** The root page number of the new table is left in reg pParse->regRoot.
+    ** The rowid and root page number values are needed by the code that
+    ** sqlite3EndTable will generate.
+    */
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+    if( isView || isVirtual ){
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, reg2);
+    }else
+#endif
+    {
+      assert( !pParse->bReturning );
+      pParse->u1.addrCrTab =
+         sqlite3VdbeAddOp3(v, OP_CreateBtree, iDb, reg2, BTREE_INTKEY);
+    }
+    sqlite3OpenSchemaTable(pParse, iDb);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, 0, reg1);
+    sqlite3VdbeAddOp4(v, OP_Blob, 6, reg3, 0, nullRow, P4_STATIC);
+    sqlite3VdbeAddOp3(v, OP_Insert, 0, reg3, reg1);
+    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+    sqlite3VdbeAddOp0(v, OP_Close);
+  }
+
+  /* Normal (non-error) return. */
+  return;
+
+  /* If an error occurs, we jump here */
+begin_table_error:
+  pParse->checkSchema = 1;
+  sqlite3DbFree(db, zName);
+  return;
+}
+
+/* Set properties of a table column based on the (magical)
+** name of the column.
+*/
+#if SQLITE_ENABLE_HIDDEN_COLUMNS
+SQLITE_PRIVATE void sqlite3ColumnPropertiesFromName(Table *pTab, Column *pCol){
+  if( sqlite3_strnicmp(pCol->zCnName, "__hidden__", 10)==0 ){
+    pCol->colFlags |= COLFLAG_HIDDEN;
+    if( pTab ) pTab->tabFlags |= TF_HasHidden;
+  }else if( pTab && pCol!=pTab->aCol && (pCol[-1].colFlags & COLFLAG_HIDDEN) ){
+    pTab->tabFlags |= TF_OOOHidden;
+  }
+}
+#endif
+
+/*
+** Clean up the data structures associated with the RETURNING clause.
+*/
+static void sqlite3DeleteReturning(sqlite3 *db, void *pArg){
+  Returning *pRet = (Returning*)pArg;
+  Hash *pHash;
+  pHash = &(db->aDb[1].pSchema->trigHash);
+  sqlite3HashInsert(pHash, pRet->zName, 0);
+  sqlite3ExprListDelete(db, pRet->pReturnEL);
+  sqlite3DbFree(db, pRet);
+}
+
+/*
+** Add the RETURNING clause to the parse currently underway.
+**
+** This routine creates a special TEMP trigger that will fire for each row
+** of the DML statement.  That TEMP trigger contains a single SELECT
+** statement with a result set that is the argument of the RETURNING clause.
+** The trigger has the Trigger.bReturning flag and an opcode of
+** TK_RETURNING instead of TK_SELECT, so that the trigger code generator
+** knows to handle it specially.  The TEMP trigger is automatically
+** removed at the end of the parse.
+**
+** When this routine is called, we do not yet know if the RETURNING clause
+** is attached to a DELETE, INSERT, or UPDATE, so construct it as a
+** RETURNING trigger instead.  It will then be converted into the appropriate
+** type on the first call to sqlite3TriggersExist().
+*/
+SQLITE_PRIVATE void sqlite3AddReturning(Parse *pParse, ExprList *pList){
+  Returning *pRet;
+  Hash *pHash;
+  sqlite3 *db = pParse->db;
+  if( pParse->pNewTrigger ){
+    sqlite3ErrorMsg(pParse, "cannot use RETURNING in a trigger");
+  }else{
+    assert( pParse->bReturning==0 || pParse->ifNotExists );
+  }
+  pParse->bReturning = 1;
+  pRet = sqlite3DbMallocZero(db, sizeof(*pRet));
+  if( pRet==0 ){
+    sqlite3ExprListDelete(db, pList);
+    return;
+  }
+  pParse->u1.pReturning = pRet;
+  pRet->pParse = pParse;
+  pRet->pReturnEL = pList;
+  sqlite3ParserAddCleanup(pParse, sqlite3DeleteReturning, pRet);
+  testcase( pParse->earlyCleanup );
+  if( db->mallocFailed ) return;
+  sqlite3_snprintf(sizeof(pRet->zName), pRet->zName,
+                   "sqlite_returning_%p", pParse);
+  pRet->retTrig.zName = pRet->zName;
+  pRet->retTrig.op = TK_RETURNING;
+  pRet->retTrig.tr_tm = TRIGGER_AFTER;
+  pRet->retTrig.bReturning = 1;
+  pRet->retTrig.pSchema = db->aDb[1].pSchema;
+  pRet->retTrig.pTabSchema = db->aDb[1].pSchema;
+  pRet->retTrig.step_list = &pRet->retTStep;
+  pRet->retTStep.op = TK_RETURNING;
+  pRet->retTStep.pTrig = &pRet->retTrig;
+  pRet->retTStep.pExprList = pList;
+  pHash = &(db->aDb[1].pSchema->trigHash);
+  assert( sqlite3HashFind(pHash, pRet->zName)==0
+          || pParse->nErr  || pParse->ifNotExists );
+  if( sqlite3HashInsert(pHash, pRet->zName, &pRet->retTrig)
+          ==&pRet->retTrig ){
+    sqlite3OomFault(db);
+  }
+}
+
+/*
+** Add a new column to the table currently being constructed.
+**
+** The parser calls this routine once for each column declaration
+** in a CREATE TABLE statement.  sqlite3StartTable() gets called
+** first to get things going.  Then this routine is called for each
+** column.
+*/
+SQLITE_PRIVATE void sqlite3AddColumn(Parse *pParse, Token sName, Token sType){
+  Table *p;
+  int i;
+  char *z;
+  char *zType;
+  Column *pCol;
+  sqlite3 *db = pParse->db;
+  u8 hName;
+  Column *aNew;
+  u8 eType = COLTYPE_CUSTOM;
+  u8 szEst = 1;
+  char affinity = SQLITE_AFF_BLOB;
+
+  if( (p = pParse->pNewTable)==0 ) return;
+  if( p->nCol+1>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many columns on %s", p->zName);
+    return;
+  }
+  if( !IN_RENAME_OBJECT ) sqlite3DequoteToken(&sName);
+
+  /* Because keywords GENERATE ALWAYS can be converted into identifiers
+  ** by the parser, we can sometimes end up with a typename that ends
+  ** with "generated always".  Check for this case and omit the surplus
+  ** text. */
+  if( sType.n>=16
+   && sqlite3_strnicmp(sType.z+(sType.n-6),"always",6)==0
+  ){
+    sType.n -= 6;
+    while( ALWAYS(sType.n>0) && sqlite3Isspace(sType.z[sType.n-1]) ) sType.n--;
+    if( sType.n>=9
+     && sqlite3_strnicmp(sType.z+(sType.n-9),"generated",9)==0
+    ){
+      sType.n -= 9;
+      while( sType.n>0 && sqlite3Isspace(sType.z[sType.n-1]) ) sType.n--;
+    }
+  }
+
+  /* Check for standard typenames.  For standard typenames we will
+  ** set the Column.eType field rather than storing the typename after
+  ** the column name, in order to save space. */
+  if( sType.n>=3 ){
+    sqlite3DequoteToken(&sType);
+    for(i=0; i<SQLITE_N_STDTYPE; i++){
+       if( sType.n==sqlite3StdTypeLen[i]
+        && sqlite3_strnicmp(sType.z, sqlite3StdType[i], sType.n)==0
+       ){
+         sType.n = 0;
+         eType = i+1;
+         affinity = sqlite3StdTypeAffinity[i];
+         if( affinity<=SQLITE_AFF_TEXT ) szEst = 5;
+         break;
+       }
+    }
+  }
+
+  z = sqlite3DbMallocRaw(db, (i64)sName.n + 1 + (i64)sType.n + (sType.n>0) );
+  if( z==0 ) return;
+  if( IN_RENAME_OBJECT ) sqlite3RenameTokenMap(pParse, (void*)z, &sName);
+  memcpy(z, sName.z, sName.n);
+  z[sName.n] = 0;
+  sqlite3Dequote(z);
+  hName = sqlite3StrIHash(z);
+  for(i=0; i<p->nCol; i++){
+    if( p->aCol[i].hName==hName && sqlite3StrICmp(z, p->aCol[i].zCnName)==0 ){
+      sqlite3ErrorMsg(pParse, "duplicate column name: %s", z);
+      sqlite3DbFree(db, z);
+      return;
+    }
+  }
+  aNew = sqlite3DbRealloc(db,p->aCol,((i64)p->nCol+1)*sizeof(p->aCol[0]));
+  if( aNew==0 ){
+    sqlite3DbFree(db, z);
+    return;
+  }
+  p->aCol = aNew;
+  pCol = &p->aCol[p->nCol];
+  memset(pCol, 0, sizeof(p->aCol[0]));
+  pCol->zCnName = z;
+  pCol->hName = hName;
+  sqlite3ColumnPropertiesFromName(p, pCol);
+
+  if( sType.n==0 ){
+    /* If there is no type specified, columns have the default affinity
+    ** 'BLOB' with a default size of 4 bytes. */
+    pCol->affinity = affinity;
+    pCol->eCType = eType;
+    pCol->szEst = szEst;
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( affinity==SQLITE_AFF_BLOB ){
+      if( 4>=sqlite3GlobalConfig.szSorterRef ){
+        pCol->colFlags |= COLFLAG_SORTERREF;
+      }
+    }
+#endif
+  }else{
+    zType = z + sqlite3Strlen30(z) + 1;
+    memcpy(zType, sType.z, sType.n);
+    zType[sType.n] = 0;
+    sqlite3Dequote(zType);
+    pCol->affinity = sqlite3AffinityType(zType, pCol);
+    pCol->colFlags |= COLFLAG_HASTYPE;
+  }
+  p->nCol++;
+  p->nNVCol++;
+  pParse->constraintName.n = 0;
+}
+
+/*
+** This routine is called by the parser while in the middle of
+** parsing a CREATE TABLE statement.  A "NOT NULL" constraint has
+** been seen on a column.  This routine sets the notNull flag on
+** the column currently under construction.
+*/
+SQLITE_PRIVATE void sqlite3AddNotNull(Parse *pParse, int onError){
+  Table *p;
+  Column *pCol;
+  p = pParse->pNewTable;
+  if( p==0 || NEVER(p->nCol<1) ) return;
+  pCol = &p->aCol[p->nCol-1];
+  pCol->notNull = (u8)onError;
+  p->tabFlags |= TF_HasNotNull;
+
+  /* Set the uniqNotNull flag on any UNIQUE or PK indexes already created
+  ** on this column.  */
+  if( pCol->colFlags & COLFLAG_UNIQUE ){
+    Index *pIdx;
+    for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
+      assert( pIdx->nKeyCol==1 && pIdx->onError!=OE_None );
+      if( pIdx->aiColumn[0]==p->nCol-1 ){
+        pIdx->uniqNotNull = 1;
+      }
+    }
+  }
+}
+
+/*
+** Scan the column type name zType (length nType) and return the
+** associated affinity type.
+**
+** This routine does a case-independent search of zType for the
+** substrings in the following table. If one of the substrings is
+** found, the corresponding affinity is returned. If zType contains
+** more than one of the substrings, entries toward the top of
+** the table take priority. For example, if zType is 'BLOBINT',
+** SQLITE_AFF_INTEGER is returned.
+**
+** Substring     | Affinity
+** --------------------------------
+** 'INT'         | SQLITE_AFF_INTEGER
+** 'CHAR'        | SQLITE_AFF_TEXT
+** 'CLOB'        | SQLITE_AFF_TEXT
+** 'TEXT'        | SQLITE_AFF_TEXT
+** 'BLOB'        | SQLITE_AFF_BLOB
+** 'REAL'        | SQLITE_AFF_REAL
+** 'FLOA'        | SQLITE_AFF_REAL
+** 'DOUB'        | SQLITE_AFF_REAL
+**
+** If none of the substrings in the above table are found,
+** SQLITE_AFF_NUMERIC is returned.
+*/
+SQLITE_PRIVATE char sqlite3AffinityType(const char *zIn, Column *pCol){
+  u32 h = 0;
+  char aff = SQLITE_AFF_NUMERIC;
+  const char *zChar = 0;
+
+  assert( zIn!=0 );
+  while( zIn[0] ){
+    u8 x = *(u8*)zIn;
+    h = (h<<8) + sqlite3UpperToLower[x];
+    zIn++;
+    if( h==(('c'<<24)+('h'<<16)+('a'<<8)+'r') ){             /* CHAR */
+      aff = SQLITE_AFF_TEXT;
+      zChar = zIn;
+    }else if( h==(('c'<<24)+('l'<<16)+('o'<<8)+'b') ){       /* CLOB */
+      aff = SQLITE_AFF_TEXT;
+    }else if( h==(('t'<<24)+('e'<<16)+('x'<<8)+'t') ){       /* TEXT */
+      aff = SQLITE_AFF_TEXT;
+    }else if( h==(('b'<<24)+('l'<<16)+('o'<<8)+'b')          /* BLOB */
+        && (aff==SQLITE_AFF_NUMERIC || aff==SQLITE_AFF_REAL) ){
+      aff = SQLITE_AFF_BLOB;
+      if( zIn[0]=='(' ) zChar = zIn;
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    }else if( h==(('r'<<24)+('e'<<16)+('a'<<8)+'l')          /* REAL */
+        && aff==SQLITE_AFF_NUMERIC ){
+      aff = SQLITE_AFF_REAL;
+    }else if( h==(('f'<<24)+('l'<<16)+('o'<<8)+'a')          /* FLOA */
+        && aff==SQLITE_AFF_NUMERIC ){
+      aff = SQLITE_AFF_REAL;
+    }else if( h==(('d'<<24)+('o'<<16)+('u'<<8)+'b')          /* DOUB */
+        && aff==SQLITE_AFF_NUMERIC ){
+      aff = SQLITE_AFF_REAL;
+#endif
+    }else if( (h&0x00FFFFFF)==(('i'<<16)+('n'<<8)+'t') ){    /* INT */
+      aff = SQLITE_AFF_INTEGER;
+      break;
+    }
+  }
+
+  /* If pCol is not NULL, store an estimate of the field size.  The
+  ** estimate is scaled so that the size of an integer is 1.  */
+  if( pCol ){
+    int v = 0;   /* default size is approx 4 bytes */
+    if( aff<SQLITE_AFF_NUMERIC ){
+      if( zChar ){
+        while( zChar[0] ){
+          if( sqlite3Isdigit(zChar[0]) ){
+            /* BLOB(k), VARCHAR(k), CHAR(k) -> r=(k/4+1) */
+            sqlite3GetInt32(zChar, &v);
+            break;
+          }
+          zChar++;
+        }
+      }else{
+        v = 16;   /* BLOB, TEXT, CLOB -> r=5  (approx 20 bytes)*/
+      }
+    }
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( v>=sqlite3GlobalConfig.szSorterRef ){
+      pCol->colFlags |= COLFLAG_SORTERREF;
+    }
+#endif
+    v = v/4 + 1;
+    if( v>255 ) v = 255;
+    pCol->szEst = v;
+  }
+  return aff;
+}
+
+/*
+** The expression is the default value for the most recently added column
+** of the table currently under construction.
+**
+** Default value expressions must be constant.  Raise an exception if this
+** is not the case.
+**
+** This routine is called by the parser while in the middle of
+** parsing a CREATE TABLE statement.
+*/
+SQLITE_PRIVATE void sqlite3AddDefaultValue(
+  Parse *pParse,           /* Parsing context */
+  Expr *pExpr,             /* The parsed expression of the default value */
+  const char *zStart,      /* Start of the default value text */
+  const char *zEnd         /* First character past end of default value text */
+){
+  Table *p;
+  Column *pCol;
+  sqlite3 *db = pParse->db;
+  p = pParse->pNewTable;
+  if( p!=0 ){
+    int isInit = db->init.busy && db->init.iDb!=1;
+    pCol = &(p->aCol[p->nCol-1]);
+    if( !sqlite3ExprIsConstantOrFunction(pExpr, isInit) ){
+      sqlite3ErrorMsg(pParse, "default value of column [%s] is not constant",
+          pCol->zCnName);
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    }else if( pCol->colFlags & COLFLAG_GENERATED ){
+      testcase( pCol->colFlags & COLFLAG_VIRTUAL );
+      testcase( pCol->colFlags & COLFLAG_STORED );
+      sqlite3ErrorMsg(pParse, "cannot use DEFAULT on a generated column");
+#endif
+    }else{
+      /* A copy of pExpr is used instead of the original, as pExpr contains
+      ** tokens that point to volatile memory.
+      */
+      Expr x, *pDfltExpr;
+      memset(&x, 0, sizeof(x));
+      x.op = TK_SPAN;
+      x.u.zToken = sqlite3DbSpanDup(db, zStart, zEnd);
+      x.pLeft = pExpr;
+      x.flags = EP_Skip;
+      pDfltExpr = sqlite3ExprDup(db, &x, EXPRDUP_REDUCE);
+      sqlite3DbFree(db, x.u.zToken);
+      sqlite3ColumnSetExpr(pParse, p, pCol, pDfltExpr);
+    }
+  }
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameExprUnmap(pParse, pExpr);
+  }
+  sqlite3ExprDelete(db, pExpr);
+}
+
+/*
+** Backwards Compatibility Hack:
+**
+** Historical versions of SQLite accepted strings as column names in
+** indexes and PRIMARY KEY constraints and in UNIQUE constraints.  Example:
+**
+**     CREATE TABLE xyz(a,b,c,d,e,PRIMARY KEY('a'),UNIQUE('b','c' COLLATE trim)
+**     CREATE INDEX abc ON xyz('c','d' DESC,'e' COLLATE nocase DESC);
+**
+** This is goofy.  But to preserve backwards compatibility we continue to
+** accept it.  This routine does the necessary conversion.  It converts
+** the expression given in its argument from a TK_STRING into a TK_ID
+** if the expression is just a TK_STRING with an optional COLLATE clause.
+** If the expression is anything other than TK_STRING, the expression is
+** unchanged.
+*/
+static void sqlite3StringToId(Expr *p){
+  if( p->op==TK_STRING ){
+    p->op = TK_ID;
+  }else if( p->op==TK_COLLATE && p->pLeft->op==TK_STRING ){
+    p->pLeft->op = TK_ID;
+  }
+}
+
+/*
+** Tag the given column as being part of the PRIMARY KEY
+*/
+static void makeColumnPartOfPrimaryKey(Parse *pParse, Column *pCol){
+  pCol->colFlags |= COLFLAG_PRIMKEY;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  if( pCol->colFlags & COLFLAG_GENERATED ){
+    testcase( pCol->colFlags & COLFLAG_VIRTUAL );
+    testcase( pCol->colFlags & COLFLAG_STORED );
+    sqlite3ErrorMsg(pParse,
+      "generated columns cannot be part of the PRIMARY KEY");
+  }
+#endif
+}
+
+/*
+** Designate the PRIMARY KEY for the table.  pList is a list of names
+** of columns that form the primary key.  If pList is NULL, then the
+** most recently added column of the table is the primary key.
+**
+** A table can have at most one primary key.  If the table already has
+** a primary key (and this is the second primary key) then create an
+** error.
+**
+** If the PRIMARY KEY is on a single column whose datatype is INTEGER,
+** then we will try to use that column as the rowid.  Set the Table.iPKey
+** field of the table under construction to be the index of the
+** INTEGER PRIMARY KEY column.  Table.iPKey is set to -1 if there is
+** no INTEGER PRIMARY KEY.
+**
+** If the key is not an INTEGER PRIMARY KEY, then create a unique
+** index for the key.  No index is created for INTEGER PRIMARY KEYs.
+*/
+SQLITE_PRIVATE void sqlite3AddPrimaryKey(
+  Parse *pParse,    /* Parsing context */
+  ExprList *pList,  /* List of field names to be indexed */
+  int onError,      /* What to do with a uniqueness conflict */
+  int autoInc,      /* True if the AUTOINCREMENT keyword is present */
+  int sortOrder     /* SQLITE_SO_ASC or SQLITE_SO_DESC */
+){
+  Table *pTab = pParse->pNewTable;
+  Column *pCol = 0;
+  int iCol = -1, i;
+  int nTerm;
+  if( pTab==0 ) goto primary_key_exit;
+  if( pTab->tabFlags & TF_HasPrimaryKey ){
+    sqlite3ErrorMsg(pParse,
+      "table \"%s\" has more than one primary key", pTab->zName);
+    goto primary_key_exit;
+  }
+  pTab->tabFlags |= TF_HasPrimaryKey;
+  if( pList==0 ){
+    iCol = pTab->nCol - 1;
+    pCol = &pTab->aCol[iCol];
+    makeColumnPartOfPrimaryKey(pParse, pCol);
+    nTerm = 1;
+  }else{
+    nTerm = pList->nExpr;
+    for(i=0; i<nTerm; i++){
+      Expr *pCExpr = sqlite3ExprSkipCollate(pList->a[i].pExpr);
+      assert( pCExpr!=0 );
+      sqlite3StringToId(pCExpr);
+      if( pCExpr->op==TK_ID ){
+        const char *zCName;
+        assert( !ExprHasProperty(pCExpr, EP_IntValue) );
+        zCName = pCExpr->u.zToken;
+        for(iCol=0; iCol<pTab->nCol; iCol++){
+          if( sqlite3StrICmp(zCName, pTab->aCol[iCol].zCnName)==0 ){
+            pCol = &pTab->aCol[iCol];
+            makeColumnPartOfPrimaryKey(pParse, pCol);
+            break;
+          }
+        }
+      }
+    }
+  }
+  if( nTerm==1
+   && pCol
+   && pCol->eCType==COLTYPE_INTEGER
+   && sortOrder!=SQLITE_SO_DESC
+  ){
+    if( IN_RENAME_OBJECT && pList ){
+      Expr *pCExpr = sqlite3ExprSkipCollate(pList->a[0].pExpr);
+      sqlite3RenameTokenRemap(pParse, &pTab->iPKey, pCExpr);
+    }
+    pTab->iPKey = iCol;
+    pTab->keyConf = (u8)onError;
+    assert( autoInc==0 || autoInc==1 );
+    pTab->tabFlags |= autoInc*TF_Autoincrement;
+    if( pList ) pParse->iPkSortOrder = pList->a[0].fg.sortFlags;
+    (void)sqlite3HasExplicitNulls(pParse, pList);
+  }else if( autoInc ){
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    sqlite3ErrorMsg(pParse, "AUTOINCREMENT is only allowed on an "
+       "INTEGER PRIMARY KEY");
+#endif
+  }else{
+    sqlite3CreateIndex(pParse, 0, 0, 0, pList, onError, 0,
+                           0, sortOrder, 0, SQLITE_IDXTYPE_PRIMARYKEY);
+    pList = 0;
+  }
+
+primary_key_exit:
+  sqlite3ExprListDelete(pParse->db, pList);
+  return;
+}
+
+/*
+** Add a new CHECK constraint to the table currently under construction.
+*/
+SQLITE_PRIVATE void sqlite3AddCheckConstraint(
+  Parse *pParse,      /* Parsing context */
+  Expr *pCheckExpr,   /* The check expression */
+  const char *zStart, /* Opening "(" */
+  const char *zEnd    /* Closing ")" */
+){
+#ifndef SQLITE_OMIT_CHECK
+  Table *pTab = pParse->pNewTable;
+  sqlite3 *db = pParse->db;
+  if( pTab && !IN_DECLARE_VTAB
+   && !sqlite3BtreeIsReadonly(db->aDb[db->init.iDb].pBt)
+  ){
+    pTab->pCheck = sqlite3ExprListAppend(pParse, pTab->pCheck, pCheckExpr);
+    if( pParse->constraintName.n ){
+      sqlite3ExprListSetName(pParse, pTab->pCheck, &pParse->constraintName, 1);
+    }else{
+      Token t;
+      for(zStart++; sqlite3Isspace(zStart[0]); zStart++){}
+      while( sqlite3Isspace(zEnd[-1]) ){ zEnd--; }
+      t.z = zStart;
+      t.n = (int)(zEnd - t.z);
+      sqlite3ExprListSetName(pParse, pTab->pCheck, &t, 1);
+    }
+  }else
+#endif
+  {
+    sqlite3ExprDelete(pParse->db, pCheckExpr);
+  }
+}
+
+/*
+** Set the collation function of the most recently parsed table column
+** to the CollSeq given.
+*/
+SQLITE_PRIVATE void sqlite3AddCollateType(Parse *pParse, Token *pToken){
+  Table *p;
+  int i;
+  char *zColl;              /* Dequoted name of collation sequence */
+  sqlite3 *db;
+
+  if( (p = pParse->pNewTable)==0 || IN_RENAME_OBJECT ) return;
+  i = p->nCol-1;
+  db = pParse->db;
+  zColl = sqlite3NameFromToken(db, pToken);
+  if( !zColl ) return;
+
+  if( sqlite3LocateCollSeq(pParse, zColl) ){
+    Index *pIdx;
+    sqlite3ColumnSetColl(db, &p->aCol[i], zColl);
+
+    /* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
+    ** then an index may have been created on this column before the
+    ** collation type was added. Correct this if it is the case.
+    */
+    for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
+      assert( pIdx->nKeyCol==1 );
+      if( pIdx->aiColumn[0]==i ){
+        pIdx->azColl[0] = sqlite3ColumnColl(&p->aCol[i]);
+      }
+    }
+  }
+  sqlite3DbFree(db, zColl);
+}
+
+/* Change the most recently parsed column to be a GENERATED ALWAYS AS
+** column.
+*/
+SQLITE_PRIVATE void sqlite3AddGenerated(Parse *pParse, Expr *pExpr, Token *pType){
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  u8 eType = COLFLAG_VIRTUAL;
+  Table *pTab = pParse->pNewTable;
+  Column *pCol;
+  if( pTab==0 ){
+    /* generated column in an CREATE TABLE IF NOT EXISTS that already exists */
+    goto generated_done;
+  }
+  pCol = &(pTab->aCol[pTab->nCol-1]);
+  if( IN_DECLARE_VTAB ){
+    sqlite3ErrorMsg(pParse, "virtual tables cannot use computed columns");
+    goto generated_done;
+  }
+  if( pCol->iDflt>0 ) goto generated_error;
+  if( pType ){
+    if( pType->n==7 && sqlite3StrNICmp("virtual",pType->z,7)==0 ){
+      /* no-op */
+    }else if( pType->n==6 && sqlite3StrNICmp("stored",pType->z,6)==0 ){
+      eType = COLFLAG_STORED;
+    }else{
+      goto generated_error;
+    }
+  }
+  if( eType==COLFLAG_VIRTUAL ) pTab->nNVCol--;
+  pCol->colFlags |= eType;
+  assert( TF_HasVirtual==COLFLAG_VIRTUAL );
+  assert( TF_HasStored==COLFLAG_STORED );
+  pTab->tabFlags |= eType;
+  if( pCol->colFlags & COLFLAG_PRIMKEY ){
+    makeColumnPartOfPrimaryKey(pParse, pCol); /* For the error message */
+  }
+  if( ALWAYS(pExpr) && pExpr->op==TK_ID ){
+    /* The value of a generated column needs to be a real expression, not
+    ** just a reference to another column, in order for covering index
+    ** optimizations to work correctly.  So if the value is not an expression,
+    ** turn it into one by adding a unary "+" operator. */
+    pExpr = sqlite3PExpr(pParse, TK_UPLUS, pExpr, 0);
+  }
+  if( pExpr && pExpr->op!=TK_RAISE ) pExpr->affExpr = pCol->affinity;
+  sqlite3ColumnSetExpr(pParse, pTab, pCol, pExpr);
+  pExpr = 0;
+  goto generated_done;
+
+generated_error:
+  sqlite3ErrorMsg(pParse, "error in generated column \"%s\"",
+                  pCol->zCnName);
+generated_done:
+  sqlite3ExprDelete(pParse->db, pExpr);
+#else
+  /* Throw and error for the GENERATED ALWAYS AS clause if the
+  ** SQLITE_OMIT_GENERATED_COLUMNS compile-time option is used. */
+  sqlite3ErrorMsg(pParse, "generated columns not supported");
+  sqlite3ExprDelete(pParse->db, pExpr);
+#endif
+}
+
+/*
+** Generate code that will increment the schema cookie.
+**
+** The schema cookie is used to determine when the schema for the
+** database changes.  After each schema change, the cookie value
+** changes.  When a process first reads the schema it records the
+** cookie.  Thereafter, whenever it goes to access the database,
+** it checks the cookie to make sure the schema has not changed
+** since it was last read.
+**
+** This plan is not completely bullet-proof.  It is possible for
+** the schema to change multiple times and for the cookie to be
+** set back to prior value.  But schema changes are infrequent
+** and the probability of hitting the same cookie value is only
+** 1 chance in 2^32.  So we're safe enough.
+**
+** IMPLEMENTATION-OF: R-34230-56049 SQLite automatically increments
+** the schema-version whenever the schema changes.
+*/
+SQLITE_PRIVATE void sqlite3ChangeCookie(Parse *pParse, int iDb){
+  sqlite3 *db = pParse->db;
+  Vdbe *v = pParse->pVdbe;
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_SCHEMA_VERSION,
+                   (int)(1+(unsigned)db->aDb[iDb].pSchema->schema_cookie));
+}
+
+/*
+** Measure the number of characters needed to output the given
+** identifier.  The number returned includes any quotes used
+** but does not include the null terminator.
+**
+** The estimate is conservative.  It might be larger that what is
+** really needed.
+*/
+static int identLength(const char *z){
+  int n;
+  for(n=0; *z; n++, z++){
+    if( *z=='"' ){ n++; }
+  }
+  return n + 2;
+}
+
+/*
+** The first parameter is a pointer to an output buffer. The second
+** parameter is a pointer to an integer that contains the offset at
+** which to write into the output buffer. This function copies the
+** nul-terminated string pointed to by the third parameter, zSignedIdent,
+** to the specified offset in the buffer and updates *pIdx to refer
+** to the first byte after the last byte written before returning.
+**
+** If the string zSignedIdent consists entirely of alphanumeric
+** characters, does not begin with a digit and is not an SQL keyword,
+** then it is copied to the output buffer exactly as it is. Otherwise,
+** it is quoted using double-quotes.
+*/
+static void identPut(char *z, int *pIdx, char *zSignedIdent){
+  unsigned char *zIdent = (unsigned char*)zSignedIdent;
+  int i, j, needQuote;
+  i = *pIdx;
+
+  for(j=0; zIdent[j]; j++){
+    if( !sqlite3Isalnum(zIdent[j]) && zIdent[j]!='_' ) break;
+  }
+  needQuote = sqlite3Isdigit(zIdent[0])
+            || sqlite3KeywordCode(zIdent, j)!=TK_ID
+            || zIdent[j]!=0
+            || j==0;
+
+  if( needQuote ) z[i++] = '"';
+  for(j=0; zIdent[j]; j++){
+    z[i++] = zIdent[j];
+    if( zIdent[j]=='"' ) z[i++] = '"';
+  }
+  if( needQuote ) z[i++] = '"';
+  z[i] = 0;
+  *pIdx = i;
+}
+
+/*
+** Generate a CREATE TABLE statement appropriate for the given
+** table.  Memory to hold the text of the statement is obtained
+** from sqliteMalloc() and must be freed by the calling function.
+*/
+static char *createTableStmt(sqlite3 *db, Table *p){
+  int i, k, n;
+  char *zStmt;
+  char *zSep, *zSep2, *zEnd;
+  Column *pCol;
+  n = 0;
+  for(pCol = p->aCol, i=0; i<p->nCol; i++, pCol++){
+    n += identLength(pCol->zCnName) + 5;
+  }
+  n += identLength(p->zName);
+  if( n<50 ){
+    zSep = "";
+    zSep2 = ",";
+    zEnd = ")";
+  }else{
+    zSep = "\n  ";
+    zSep2 = ",\n  ";
+    zEnd = "\n)";
+  }
+  n += 35 + 6*p->nCol;
+  zStmt = sqlite3DbMallocRaw(0, n);
+  if( zStmt==0 ){
+    sqlite3OomFault(db);
+    return 0;
+  }
+  sqlite3_snprintf(n, zStmt, "CREATE TABLE ");
+  k = sqlite3Strlen30(zStmt);
+  identPut(zStmt, &k, p->zName);
+  zStmt[k++] = '(';
+  for(pCol=p->aCol, i=0; i<p->nCol; i++, pCol++){
+    static const char * const azType[] = {
+        /* SQLITE_AFF_BLOB    */ "",
+        /* SQLITE_AFF_TEXT    */ " TEXT",
+        /* SQLITE_AFF_NUMERIC */ " NUM",
+        /* SQLITE_AFF_INTEGER */ " INT",
+        /* SQLITE_AFF_REAL    */ " REAL",
+        /* SQLITE_AFF_FLEXNUM */ " NUM",
+    };
+    int len;
+    const char *zType;
+
+    sqlite3_snprintf(n-k, &zStmt[k], zSep);
+    k += sqlite3Strlen30(&zStmt[k]);
+    zSep = zSep2;
+    identPut(zStmt, &k, pCol->zCnName);
+    assert( pCol->affinity-SQLITE_AFF_BLOB >= 0 );
+    assert( pCol->affinity-SQLITE_AFF_BLOB < ArraySize(azType) );
+    testcase( pCol->affinity==SQLITE_AFF_BLOB );
+    testcase( pCol->affinity==SQLITE_AFF_TEXT );
+    testcase( pCol->affinity==SQLITE_AFF_NUMERIC );
+    testcase( pCol->affinity==SQLITE_AFF_INTEGER );
+    testcase( pCol->affinity==SQLITE_AFF_REAL );
+    testcase( pCol->affinity==SQLITE_AFF_FLEXNUM );
+
+    zType = azType[pCol->affinity - SQLITE_AFF_BLOB];
+    len = sqlite3Strlen30(zType);
+    assert( pCol->affinity==SQLITE_AFF_BLOB
+            || pCol->affinity==SQLITE_AFF_FLEXNUM
+            || pCol->affinity==sqlite3AffinityType(zType, 0) );
+    memcpy(&zStmt[k], zType, len);
+    k += len;
+    assert( k<=n );
+  }
+  sqlite3_snprintf(n-k, &zStmt[k], "%s", zEnd);
+  return zStmt;
+}
+
+/*
+** Resize an Index object to hold N columns total.  Return SQLITE_OK
+** on success and SQLITE_NOMEM on an OOM error.
+*/
+static int resizeIndexObject(sqlite3 *db, Index *pIdx, int N){
+  char *zExtra;
+  int nByte;
+  if( pIdx->nColumn>=N ) return SQLITE_OK;
+  assert( pIdx->isResized==0 );
+  nByte = (sizeof(char*) + sizeof(LogEst) + sizeof(i16) + 1)*N;
+  zExtra = sqlite3DbMallocZero(db, nByte);
+  if( zExtra==0 ) return SQLITE_NOMEM_BKPT;
+  memcpy(zExtra, pIdx->azColl, sizeof(char*)*pIdx->nColumn);
+  pIdx->azColl = (const char**)zExtra;
+  zExtra += sizeof(char*)*N;
+  memcpy(zExtra, pIdx->aiRowLogEst, sizeof(LogEst)*(pIdx->nKeyCol+1));
+  pIdx->aiRowLogEst = (LogEst*)zExtra;
+  zExtra += sizeof(LogEst)*N;
+  memcpy(zExtra, pIdx->aiColumn, sizeof(i16)*pIdx->nColumn);
+  pIdx->aiColumn = (i16*)zExtra;
+  zExtra += sizeof(i16)*N;
+  memcpy(zExtra, pIdx->aSortOrder, pIdx->nColumn);
+  pIdx->aSortOrder = (u8*)zExtra;
+  pIdx->nColumn = N;
+  pIdx->isResized = 1;
+  return SQLITE_OK;
+}
+
+/*
+** Estimate the total row width for a table.
+*/
+static void estimateTableWidth(Table *pTab){
+  unsigned wTable = 0;
+  const Column *pTabCol;
+  int i;
+  for(i=pTab->nCol, pTabCol=pTab->aCol; i>0; i--, pTabCol++){
+    wTable += pTabCol->szEst;
+  }
+  if( pTab->iPKey<0 ) wTable++;
+  pTab->szTabRow = sqlite3LogEst(wTable*4);
+}
+
+/*
+** Estimate the average size of a row for an index.
+*/
+static void estimateIndexWidth(Index *pIdx){
+  unsigned wIndex = 0;
+  int i;
+  const Column *aCol = pIdx->pTable->aCol;
+  for(i=0; i<pIdx->nColumn; i++){
+    i16 x = pIdx->aiColumn[i];
+    assert( x<pIdx->pTable->nCol );
+    wIndex += x<0 ? 1 : aCol[x].szEst;
+  }
+  pIdx->szIdxRow = sqlite3LogEst(wIndex*4);
+}
+
+/* Return true if column number x is any of the first nCol entries of aiCol[].
+** This is used to determine if the column number x appears in any of the
+** first nCol entries of an index.
+*/
+static int hasColumn(const i16 *aiCol, int nCol, int x){
+  while( nCol-- > 0 ){
+    if( x==*(aiCol++) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Return true if any of the first nKey entries of index pIdx exactly
+** match the iCol-th entry of pPk.  pPk is always a WITHOUT ROWID
+** PRIMARY KEY index.  pIdx is an index on the same table.  pIdx may
+** or may not be the same index as pPk.
+**
+** The first nKey entries of pIdx are guaranteed to be ordinary columns,
+** not a rowid or expression.
+**
+** This routine differs from hasColumn() in that both the column and the
+** collating sequence must match for this routine, but for hasColumn() only
+** the column name must match.
+*/
+static int isDupColumn(Index *pIdx, int nKey, Index *pPk, int iCol){
+  int i, j;
+  assert( nKey<=pIdx->nColumn );
+  assert( iCol<MAX(pPk->nColumn,pPk->nKeyCol) );
+  assert( pPk->idxType==SQLITE_IDXTYPE_PRIMARYKEY );
+  assert( pPk->pTable->tabFlags & TF_WithoutRowid );
+  assert( pPk->pTable==pIdx->pTable );
+  testcase( pPk==pIdx );
+  j = pPk->aiColumn[iCol];
+  assert( j!=XN_ROWID && j!=XN_EXPR );
+  for(i=0; i<nKey; i++){
+    assert( pIdx->aiColumn[i]>=0 || j>=0 );
+    if( pIdx->aiColumn[i]==j
+     && sqlite3StrICmp(pIdx->azColl[i], pPk->azColl[iCol])==0
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/* Recompute the colNotIdxed field of the Index.
+**
+** colNotIdxed is a bitmask that has a 0 bit representing each indexed
+** columns that are within the first 63 columns of the table and a 1 for
+** all other bits (all columns that are not in the index).  The
+** high-order bit of colNotIdxed is always 1.  All unindexed columns
+** of the table have a 1.
+**
+** 2019-10-24:  For the purpose of this computation, virtual columns are
+** not considered to be covered by the index, even if they are in the
+** index, because we do not trust the logic in whereIndexExprTrans() to be
+** able to find all instances of a reference to the indexed table column
+** and convert them into references to the index.  Hence we always want
+** the actual table at hand in order to recompute the virtual column, if
+** necessary.
+**
+** The colNotIdxed mask is AND-ed with the SrcList.a[].colUsed mask
+** to determine if the index is covering index.
+*/
+static void recomputeColumnsNotIndexed(Index *pIdx){
+  Bitmask m = 0;
+  int j;
+  Table *pTab = pIdx->pTable;
+  for(j=pIdx->nColumn-1; j>=0; j--){
+    int x = pIdx->aiColumn[j];
+    if( x>=0 && (pTab->aCol[x].colFlags & COLFLAG_VIRTUAL)==0 ){
+      testcase( x==BMS-1 );
+      testcase( x==BMS-2 );
+      if( x<BMS-1 ) m |= MASKBIT(x);
+    }
+  }
+  pIdx->colNotIdxed = ~m;
+  assert( (pIdx->colNotIdxed>>63)==1 );  /* See note-20221022-a */
+}
+
+/*
+** This routine runs at the end of parsing a CREATE TABLE statement that
+** has a WITHOUT ROWID clause.  The job of this routine is to convert both
+** internal schema data structures and the generated VDBE code so that they
+** are appropriate for a WITHOUT ROWID table instead of a rowid table.
+** Changes include:
+**
+**     (1)  Set all columns of the PRIMARY KEY schema object to be NOT NULL.
+**     (2)  Convert P3 parameter of the OP_CreateBtree from BTREE_INTKEY
+**          into BTREE_BLOBKEY.
+**     (3)  Bypass the creation of the sqlite_schema table entry
+**          for the PRIMARY KEY as the primary key index is now
+**          identified by the sqlite_schema table entry of the table itself.
+**     (4)  Set the Index.tnum of the PRIMARY KEY Index object in the
+**          schema to the rootpage from the main table.
+**     (5)  Add all table columns to the PRIMARY KEY Index object
+**          so that the PRIMARY KEY is a covering index.  The surplus
+**          columns are part of KeyInfo.nAllField and are not used for
+**          sorting or lookup or uniqueness checks.
+**     (6)  Replace the rowid tail on all automatically generated UNIQUE
+**          indices with the PRIMARY KEY columns.
+**
+** For virtual tables, only (1) is performed.
+*/
+static void convertToWithoutRowidTable(Parse *pParse, Table *pTab){
+  Index *pIdx;
+  Index *pPk;
+  int nPk;
+  int nExtra;
+  int i, j;
+  sqlite3 *db = pParse->db;
+  Vdbe *v = pParse->pVdbe;
+
+  /* Mark every PRIMARY KEY column as NOT NULL (except for imposter tables)
+  */
+  if( !db->init.imposterTable ){
+    for(i=0; i<pTab->nCol; i++){
+      if( (pTab->aCol[i].colFlags & COLFLAG_PRIMKEY)!=0
+       && (pTab->aCol[i].notNull==OE_None)
+      ){
+        pTab->aCol[i].notNull = OE_Abort;
+      }
+    }
+    pTab->tabFlags |= TF_HasNotNull;
+  }
+
+  /* Convert the P3 operand of the OP_CreateBtree opcode from BTREE_INTKEY
+  ** into BTREE_BLOBKEY.
+  */
+  assert( !pParse->bReturning );
+  if( pParse->u1.addrCrTab ){
+    assert( v );
+    sqlite3VdbeChangeP3(v, pParse->u1.addrCrTab, BTREE_BLOBKEY);
+  }
+
+  /* Locate the PRIMARY KEY index.  Or, if this table was originally
+  ** an INTEGER PRIMARY KEY table, create a new PRIMARY KEY index.
+  */
+  if( pTab->iPKey>=0 ){
+    ExprList *pList;
+    Token ipkToken;
+    sqlite3TokenInit(&ipkToken, pTab->aCol[pTab->iPKey].zCnName);
+    pList = sqlite3ExprListAppend(pParse, 0,
+                  sqlite3ExprAlloc(db, TK_ID, &ipkToken, 0));
+    if( pList==0 ){
+      pTab->tabFlags &= ~TF_WithoutRowid;
+      return;
+    }
+    if( IN_RENAME_OBJECT ){
+      sqlite3RenameTokenRemap(pParse, pList->a[0].pExpr, &pTab->iPKey);
+    }
+    pList->a[0].fg.sortFlags = pParse->iPkSortOrder;
+    assert( pParse->pNewTable==pTab );
+    pTab->iPKey = -1;
+    sqlite3CreateIndex(pParse, 0, 0, 0, pList, pTab->keyConf, 0, 0, 0, 0,
+                       SQLITE_IDXTYPE_PRIMARYKEY);
+    if( pParse->nErr ){
+      pTab->tabFlags &= ~TF_WithoutRowid;
+      return;
+    }
+    assert( db->mallocFailed==0 );
+    pPk = sqlite3PrimaryKeyIndex(pTab);
+    assert( pPk->nKeyCol==1 );
+  }else{
+    pPk = sqlite3PrimaryKeyIndex(pTab);
+    assert( pPk!=0 );
+
+    /*
+    ** Remove all redundant columns from the PRIMARY KEY.  For example, change
+    ** "PRIMARY KEY(a,b,a,b,c,b,c,d)" into just "PRIMARY KEY(a,b,c,d)".  Later
+    ** code assumes the PRIMARY KEY contains no repeated columns.
+    */
+    for(i=j=1; i<pPk->nKeyCol; i++){
+      if( isDupColumn(pPk, j, pPk, i) ){
+        pPk->nColumn--;
+      }else{
+        testcase( hasColumn(pPk->aiColumn, j, pPk->aiColumn[i]) );
+        pPk->azColl[j] = pPk->azColl[i];
+        pPk->aSortOrder[j] = pPk->aSortOrder[i];
+        pPk->aiColumn[j++] = pPk->aiColumn[i];
+      }
+    }
+    pPk->nKeyCol = j;
+  }
+  assert( pPk!=0 );
+  pPk->isCovering = 1;
+  if( !db->init.imposterTable ) pPk->uniqNotNull = 1;
+  nPk = pPk->nColumn = pPk->nKeyCol;
+
+  /* Bypass the creation of the PRIMARY KEY btree and the sqlite_schema
+  ** table entry. This is only required if currently generating VDBE
+  ** code for a CREATE TABLE (not when parsing one as part of reading
+  ** a database schema).  */
+  if( v && pPk->tnum>0 ){
+    assert( db->init.busy==0 );
+    sqlite3VdbeChangeOpcode(v, (int)pPk->tnum, OP_Goto);
+  }
+
+  /* The root page of the PRIMARY KEY is the table root page */
+  pPk->tnum = pTab->tnum;
+
+  /* Update the in-memory representation of all UNIQUE indices by converting
+  ** the final rowid column into one or more columns of the PRIMARY KEY.
+  */
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    int n;
+    if( IsPrimaryKeyIndex(pIdx) ) continue;
+    for(i=n=0; i<nPk; i++){
+      if( !isDupColumn(pIdx, pIdx->nKeyCol, pPk, i) ){
+        testcase( hasColumn(pIdx->aiColumn, pIdx->nKeyCol, pPk->aiColumn[i]) );
+        n++;
+      }
+    }
+    if( n==0 ){
+      /* This index is a superset of the primary key */
+      pIdx->nColumn = pIdx->nKeyCol;
+      continue;
+    }
+    if( resizeIndexObject(db, pIdx, pIdx->nKeyCol+n) ) return;
+    for(i=0, j=pIdx->nKeyCol; i<nPk; i++){
+      if( !isDupColumn(pIdx, pIdx->nKeyCol, pPk, i) ){
+        testcase( hasColumn(pIdx->aiColumn, pIdx->nKeyCol, pPk->aiColumn[i]) );
+        pIdx->aiColumn[j] = pPk->aiColumn[i];
+        pIdx->azColl[j] = pPk->azColl[i];
+        if( pPk->aSortOrder[i] ){
+          /* See ticket https://www.sqlite.org/src/info/bba7b69f9849b5bf */
+          pIdx->bAscKeyBug = 1;
+        }
+        j++;
+      }
+    }
+    assert( pIdx->nColumn>=pIdx->nKeyCol+n );
+    assert( pIdx->nColumn>=j );
+  }
+
+  /* Add all table columns to the PRIMARY KEY index
+  */
+  nExtra = 0;
+  for(i=0; i<pTab->nCol; i++){
+    if( !hasColumn(pPk->aiColumn, nPk, i)
+     && (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0 ) nExtra++;
+  }
+  if( resizeIndexObject(db, pPk, nPk+nExtra) ) return;
+  for(i=0, j=nPk; i<pTab->nCol; i++){
+    if( !hasColumn(pPk->aiColumn, j, i)
+     && (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0
+    ){
+      assert( j<pPk->nColumn );
+      pPk->aiColumn[j] = i;
+      pPk->azColl[j] = sqlite3StrBINARY;
+      j++;
+    }
+  }
+  assert( pPk->nColumn==j );
+  assert( pTab->nNVCol<=j );
+  recomputeColumnsNotIndexed(pPk);
+}
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Return true if pTab is a virtual table and zName is a shadow table name
+** for that virtual table.
+*/
+SQLITE_PRIVATE int sqlite3IsShadowTableOf(sqlite3 *db, Table *pTab, const char *zName){
+  int nName;                    /* Length of zName */
+  Module *pMod;                 /* Module for the virtual table */
+
+  if( !IsVirtual(pTab) ) return 0;
+  nName = sqlite3Strlen30(pTab->zName);
+  if( sqlite3_strnicmp(zName, pTab->zName, nName)!=0 ) return 0;
+  if( zName[nName]!='_' ) return 0;
+  pMod = (Module*)sqlite3HashFind(&db->aModule, pTab->u.vtab.azArg[0]);
+  if( pMod==0 ) return 0;
+  if( pMod->pModule->iVersion<3 ) return 0;
+  if( pMod->pModule->xShadowName==0 ) return 0;
+  return pMod->pModule->xShadowName(zName+nName+1);
+}
+#endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Table pTab is a virtual table.  If it the virtual table implementation
+** exists and has an xShadowName method, then loop over all other ordinary
+** tables within the same schema looking for shadow tables of pTab, and mark
+** any shadow tables seen using the TF_Shadow flag.
+*/
+SQLITE_PRIVATE void sqlite3MarkAllShadowTablesOf(sqlite3 *db, Table *pTab){
+  int nName;                    /* Length of pTab->zName */
+  Module *pMod;                 /* Module for the virtual table */
+  HashElem *k;                  /* For looping through the symbol table */
+
+  assert( IsVirtual(pTab) );
+  pMod = (Module*)sqlite3HashFind(&db->aModule, pTab->u.vtab.azArg[0]);
+  if( pMod==0 ) return;
+  if( NEVER(pMod->pModule==0) ) return;
+  if( pMod->pModule->iVersion<3 ) return;
+  if( pMod->pModule->xShadowName==0 ) return;
+  assert( pTab->zName!=0 );
+  nName = sqlite3Strlen30(pTab->zName);
+  for(k=sqliteHashFirst(&pTab->pSchema->tblHash); k; k=sqliteHashNext(k)){
+    Table *pOther = sqliteHashData(k);
+    assert( pOther->zName!=0 );
+    if( !IsOrdinaryTable(pOther) ) continue;
+    if( pOther->tabFlags & TF_Shadow ) continue;
+    if( sqlite3StrNICmp(pOther->zName, pTab->zName, nName)==0
+     && pOther->zName[nName]=='_'
+     && pMod->pModule->xShadowName(pOther->zName+nName+1)
+    ){
+      pOther->tabFlags |= TF_Shadow;
+    }
+  }
+}
+#endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Return true if zName is a shadow table name in the current database
+** connection.
+**
+** zName is temporarily modified while this routine is running, but is
+** restored to its original value prior to this routine returning.
+*/
+SQLITE_PRIVATE int sqlite3ShadowTableName(sqlite3 *db, const char *zName){
+  char *zTail;                  /* Pointer to the last "_" in zName */
+  Table *pTab;                  /* Table that zName is a shadow of */
+  zTail = strrchr(zName, '_');
+  if( zTail==0 ) return 0;
+  *zTail = 0;
+  pTab = sqlite3FindTable(db, zName, 0);
+  *zTail = '_';
+  if( pTab==0 ) return 0;
+  if( !IsVirtual(pTab) ) return 0;
+  return sqlite3IsShadowTableOf(db, pTab, zName);
+}
+#endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */
+
+
+#ifdef SQLITE_DEBUG
+/*
+** Mark all nodes of an expression as EP_Immutable, indicating that
+** they should not be changed.  Expressions attached to a table or
+** index definition are tagged this way to help ensure that we do
+** not pass them into code generator routines by mistake.
+*/
+static int markImmutableExprStep(Walker *pWalker, Expr *pExpr){
+  (void)pWalker;
+  ExprSetVVAProperty(pExpr, EP_Immutable);
+  return WRC_Continue;
+}
+static void markExprListImmutable(ExprList *pList){
+  if( pList ){
+    Walker w;
+    memset(&w, 0, sizeof(w));
+    w.xExprCallback = markImmutableExprStep;
+    w.xSelectCallback = sqlite3SelectWalkNoop;
+    w.xSelectCallback2 = 0;
+    sqlite3WalkExprList(&w, pList);
+  }
+}
+#else
+#define markExprListImmutable(X)  /* no-op */
+#endif /* SQLITE_DEBUG */
+
+
+/*
+** This routine is called to report the final ")" that terminates
+** a CREATE TABLE statement.
+**
+** The table structure that other action routines have been building
+** is added to the internal hash tables, assuming no errors have
+** occurred.
+**
+** An entry for the table is made in the schema table on disk, unless
+** this is a temporary table or db->init.busy==1.  When db->init.busy==1
+** it means we are reading the sqlite_schema table because we just
+** connected to the database or because the sqlite_schema table has
+** recently changed, so the entry for this table already exists in
+** the sqlite_schema table.  We do not want to create it again.
+**
+** If the pSelect argument is not NULL, it means that this routine
+** was called to create a table generated from a
+** "CREATE TABLE ... AS SELECT ..." statement.  The column names of
+** the new table will match the result set of the SELECT.
+*/
+SQLITE_PRIVATE void sqlite3EndTable(
+  Parse *pParse,          /* Parse context */
+  Token *pCons,           /* The ',' token after the last column defn. */
+  Token *pEnd,            /* The ')' before options in the CREATE TABLE */
+  u32 tabOpts,            /* Extra table options. Usually 0. */
+  Select *pSelect         /* Select from a "CREATE ... AS SELECT" */
+){
+  Table *p;                 /* The new table */
+  sqlite3 *db = pParse->db; /* The database connection */
+  int iDb;                  /* Database in which the table lives */
+  Index *pIdx;              /* An implied index of the table */
+
+  if( pEnd==0 && pSelect==0 ){
+    return;
+  }
+  p = pParse->pNewTable;
+  if( p==0 ) return;
+
+  if( pSelect==0 && sqlite3ShadowTableName(db, p->zName) ){
+    p->tabFlags |= TF_Shadow;
+  }
+
+  /* If the db->init.busy is 1 it means we are reading the SQL off the
+  ** "sqlite_schema" or "sqlite_temp_schema" table on the disk.
+  ** So do not write to the disk again.  Extract the root page number
+  ** for the table from the db->init.newTnum field.  (The page number
+  ** should have been put there by the sqliteOpenCb routine.)
+  **
+  ** If the root page number is 1, that means this is the sqlite_schema
+  ** table itself.  So mark it read-only.
+  */
+  if( db->init.busy ){
+    if( pSelect || (!IsOrdinaryTable(p) && db->init.newTnum) ){
+      sqlite3ErrorMsg(pParse, "");
+      return;
+    }
+    p->tnum = db->init.newTnum;
+    if( p->tnum==1 ) p->tabFlags |= TF_Readonly;
+  }
+
+  /* Special processing for tables that include the STRICT keyword:
+  **
+  **   *  Do not allow custom column datatypes.  Every column must have
+  **      a datatype that is one of INT, INTEGER, REAL, TEXT, or BLOB.
+  **
+  **   *  If a PRIMARY KEY is defined, other than the INTEGER PRIMARY KEY,
+  **      then all columns of the PRIMARY KEY must have a NOT NULL
+  **      constraint.
+  */
+  if( tabOpts & TF_Strict ){
+    int ii;
+    p->tabFlags |= TF_Strict;
+    for(ii=0; ii<p->nCol; ii++){
+      Column *pCol = &p->aCol[ii];
+      if( pCol->eCType==COLTYPE_CUSTOM ){
+        if( pCol->colFlags & COLFLAG_HASTYPE ){
+          sqlite3ErrorMsg(pParse,
+            "unknown datatype for %s.%s: \"%s\"",
+            p->zName, pCol->zCnName, sqlite3ColumnType(pCol, "")
+          );
+        }else{
+          sqlite3ErrorMsg(pParse, "missing datatype for %s.%s",
+                          p->zName, pCol->zCnName);
+        }
+        return;
+      }else if( pCol->eCType==COLTYPE_ANY ){
+        pCol->affinity = SQLITE_AFF_BLOB;
+      }
+      if( (pCol->colFlags & COLFLAG_PRIMKEY)!=0
+       && p->iPKey!=ii
+       && pCol->notNull == OE_None
+      ){
+        pCol->notNull = OE_Abort;
+        p->tabFlags |= TF_HasNotNull;
+      }
+    }
+  }
+
+  assert( (p->tabFlags & TF_HasPrimaryKey)==0
+       || p->iPKey>=0 || sqlite3PrimaryKeyIndex(p)!=0 );
+  assert( (p->tabFlags & TF_HasPrimaryKey)!=0
+       || (p->iPKey<0 && sqlite3PrimaryKeyIndex(p)==0) );
+
+  /* Special processing for WITHOUT ROWID Tables */
+  if( tabOpts & TF_WithoutRowid ){
+    if( (p->tabFlags & TF_Autoincrement) ){
+      sqlite3ErrorMsg(pParse,
+          "AUTOINCREMENT not allowed on WITHOUT ROWID tables");
+      return;
+    }
+    if( (p->tabFlags & TF_HasPrimaryKey)==0 ){
+      sqlite3ErrorMsg(pParse, "PRIMARY KEY missing on table %s", p->zName);
+      return;
+    }
+    p->tabFlags |= TF_WithoutRowid | TF_NoVisibleRowid;
+    convertToWithoutRowidTable(pParse, p);
+  }
+  iDb = sqlite3SchemaToIndex(db, p->pSchema);
+
+#ifndef SQLITE_OMIT_CHECK
+  /* Resolve names in all CHECK constraint expressions.
+  */
+  if( p->pCheck ){
+    sqlite3ResolveSelfReference(pParse, p, NC_IsCheck, 0, p->pCheck);
+    if( pParse->nErr ){
+      /* If errors are seen, delete the CHECK constraints now, else they might
+      ** actually be used if PRAGMA writable_schema=ON is set. */
+      sqlite3ExprListDelete(db, p->pCheck);
+      p->pCheck = 0;
+    }else{
+      markExprListImmutable(p->pCheck);
+    }
+  }
+#endif /* !defined(SQLITE_OMIT_CHECK) */
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  if( p->tabFlags & TF_HasGenerated ){
+    int ii, nNG = 0;
+    testcase( p->tabFlags & TF_HasVirtual );
+    testcase( p->tabFlags & TF_HasStored );
+    for(ii=0; ii<p->nCol; ii++){
+      u32 colFlags = p->aCol[ii].colFlags;
+      if( (colFlags & COLFLAG_GENERATED)!=0 ){
+        Expr *pX = sqlite3ColumnExpr(p, &p->aCol[ii]);
+        testcase( colFlags & COLFLAG_VIRTUAL );
+        testcase( colFlags & COLFLAG_STORED );
+        if( sqlite3ResolveSelfReference(pParse, p, NC_GenCol, pX, 0) ){
+          /* If there are errors in resolving the expression, change the
+          ** expression to a NULL.  This prevents code generators that operate
+          ** on the expression from inserting extra parts into the expression
+          ** tree that have been allocated from lookaside memory, which is
+          ** illegal in a schema and will lead to errors or heap corruption
+          ** when the database connection closes. */
+          sqlite3ColumnSetExpr(pParse, p, &p->aCol[ii],
+               sqlite3ExprAlloc(db, TK_NULL, 0, 0));
+        }
+      }else{
+        nNG++;
+      }
+    }
+    if( nNG==0 ){
+      sqlite3ErrorMsg(pParse, "must have at least one non-generated column");
+      return;
+    }
+  }
+#endif
+
+  /* Estimate the average row size for the table and for all implied indices */
+  estimateTableWidth(p);
+  for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
+    estimateIndexWidth(pIdx);
+  }
+
+  /* If not initializing, then create a record for the new table
+  ** in the schema table of the database.
+  **
+  ** If this is a TEMPORARY table, write the entry into the auxiliary
+  ** file instead of into the main database file.
+  */
+  if( !db->init.busy ){
+    int n;
+    Vdbe *v;
+    char *zType;    /* "view" or "table" */
+    char *zType2;   /* "VIEW" or "TABLE" */
+    char *zStmt;    /* Text of the CREATE TABLE or CREATE VIEW statement */
+
+    v = sqlite3GetVdbe(pParse);
+    if( NEVER(v==0) ) return;
+
+    sqlite3VdbeAddOp1(v, OP_Close, 0);
+
+    /*
+    ** Initialize zType for the new view or table.
+    */
+    if( IsOrdinaryTable(p) ){
+      /* A regular table */
+      zType = "table";
+      zType2 = "TABLE";
+#ifndef SQLITE_OMIT_VIEW
+    }else{
+      /* A view */
+      zType = "view";
+      zType2 = "VIEW";
+#endif
+    }
+
+    /* If this is a CREATE TABLE xx AS SELECT ..., execute the SELECT
+    ** statement to populate the new table. The root-page number for the
+    ** new table is in register pParse->regRoot.
+    **
+    ** Once the SELECT has been coded by sqlite3Select(), it is in a
+    ** suitable state to query for the column names and types to be used
+    ** by the new table.
+    **
+    ** A shared-cache write-lock is not required to write to the new table,
+    ** as a schema-lock must have already been obtained to create it. Since
+    ** a schema-lock excludes all other database users, the write-lock would
+    ** be redundant.
+    */
+    if( pSelect ){
+      SelectDest dest;    /* Where the SELECT should store results */
+      int regYield;       /* Register holding co-routine entry-point */
+      int addrTop;        /* Top of the co-routine */
+      int regRec;         /* A record to be insert into the new table */
+      int regRowid;       /* Rowid of the next row to insert */
+      int addrInsLoop;    /* Top of the loop for inserting rows */
+      Table *pSelTab;     /* A table that describes the SELECT results */
+      int iCsr;           /* Write cursor on the new table */
+
+      if( IN_SPECIAL_PARSE ){
+        pParse->rc = SQLITE_ERROR;
+        pParse->nErr++;
+        return;
+      }
+      iCsr = pParse->nTab++;
+      regYield = ++pParse->nMem;
+      regRec = ++pParse->nMem;
+      regRowid = ++pParse->nMem;
+      sqlite3MayAbort(pParse);
+      sqlite3VdbeAddOp3(v, OP_OpenWrite, iCsr, pParse->regRoot, iDb);
+      sqlite3VdbeChangeP5(v, OPFLAG_P2ISREG);
+      addrTop = sqlite3VdbeCurrentAddr(v) + 1;
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
+      if( pParse->nErr ) return;
+      pSelTab = sqlite3ResultSetOfSelect(pParse, pSelect, SQLITE_AFF_BLOB);
+      if( pSelTab==0 ) return;
+      assert( p->aCol==0 );
+      p->nCol = p->nNVCol = pSelTab->nCol;
+      p->aCol = pSelTab->aCol;
+      pSelTab->nCol = 0;
+      pSelTab->aCol = 0;
+      sqlite3DeleteTable(db, pSelTab);
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
+      sqlite3Select(pParse, pSelect, &dest);
+      if( pParse->nErr ) return;
+      sqlite3VdbeEndCoroutine(v, regYield);
+      sqlite3VdbeJumpHere(v, addrTop - 1);
+      addrInsLoop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, dest.iSdst, dest.nSdst, regRec);
+      sqlite3TableAffinity(v, p, 0);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, iCsr, regRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, iCsr, regRec, regRowid);
+      sqlite3VdbeGoto(v, addrInsLoop);
+      sqlite3VdbeJumpHere(v, addrInsLoop);
+      sqlite3VdbeAddOp1(v, OP_Close, iCsr);
+    }
+
+    /* Compute the complete text of the CREATE statement */
+    if( pSelect ){
+      zStmt = createTableStmt(db, p);
+    }else{
+      Token *pEnd2 = tabOpts ? &pParse->sLastToken : pEnd;
+      n = (int)(pEnd2->z - pParse->sNameToken.z);
+      if( pEnd2->z[0]!=';' ) n += pEnd2->n;
+      zStmt = sqlite3MPrintf(db,
+          "CREATE %s %.*s", zType2, n, pParse->sNameToken.z
+      );
+    }
+
+    /* A slot for the record has already been allocated in the
+    ** schema table.  We just need to update that slot with all
+    ** the information we've collected.
+    */
+    sqlite3NestedParse(pParse,
+      "UPDATE %Q." LEGACY_SCHEMA_TABLE
+      " SET type='%s', name=%Q, tbl_name=%Q, rootpage=#%d, sql=%Q"
+      " WHERE rowid=#%d",
+      db->aDb[iDb].zDbSName,
+      zType,
+      p->zName,
+      p->zName,
+      pParse->regRoot,
+      zStmt,
+      pParse->regRowid
+    );
+    sqlite3DbFree(db, zStmt);
+    sqlite3ChangeCookie(pParse, iDb);
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    /* Check to see if we need to create an sqlite_sequence table for
+    ** keeping track of autoincrement keys.
+    */
+    if( (p->tabFlags & TF_Autoincrement)!=0 && !IN_SPECIAL_PARSE ){
+      Db *pDb = &db->aDb[iDb];
+      assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+      if( pDb->pSchema->pSeqTab==0 ){
+        sqlite3NestedParse(pParse,
+          "CREATE TABLE %Q.sqlite_sequence(name,seq)",
+          pDb->zDbSName
+        );
+      }
+    }
+#endif
+
+    /* Reparse everything to update our internal data structures */
+    sqlite3VdbeAddParseSchemaOp(v, iDb,
+           sqlite3MPrintf(db, "tbl_name='%q' AND type!='trigger'", p->zName),0);
+
+    /* Test for cycles in generated columns and illegal expressions
+    ** in CHECK constraints and in DEFAULT clauses. */
+    if( p->tabFlags & TF_HasGenerated ){
+      sqlite3VdbeAddOp4(v, OP_SqlExec, 0x0001, 0, 0,
+             sqlite3MPrintf(db, "SELECT*FROM\"%w\".\"%w\"",
+                   db->aDb[iDb].zDbSName, p->zName), P4_DYNAMIC);
+    }
+  }
+
+  /* Add the table to the in-memory representation of the database.
+  */
+  if( db->init.busy ){
+    Table *pOld;
+    Schema *pSchema = p->pSchema;
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    assert( HasRowid(p) || p->iPKey<0 );
+    pOld = sqlite3HashInsert(&pSchema->tblHash, p->zName, p);
+    if( pOld ){
+      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
+      sqlite3OomFault(db);
+      return;
+    }
+    pParse->pNewTable = 0;
+    db->mDbFlags |= DBFLAG_SchemaChange;
+
+    /* If this is the magic sqlite_sequence table used by autoincrement,
+    ** then record a pointer to this table in the main database structure
+    ** so that INSERT can find the table easily.  */
+    assert( !pParse->nested );
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    if( strcmp(p->zName, "sqlite_sequence")==0 ){
+      assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+      p->pSchema->pSeqTab = p;
+    }
+#endif
+  }
+
+#ifndef SQLITE_OMIT_ALTERTABLE
+  if( !pSelect && IsOrdinaryTable(p) ){
+    assert( pCons && pEnd );
+    if( pCons->z==0 ){
+      pCons = pEnd;
+    }
+    p->u.tab.addColOffset = 13 + (int)(pCons->z - pParse->sNameToken.z);
+  }
+#endif
+}
+
+#ifndef SQLITE_OMIT_VIEW
+/*
+** The parser calls this routine in order to create a new VIEW
+*/
+SQLITE_PRIVATE void sqlite3CreateView(
+  Parse *pParse,     /* The parsing context */
+  Token *pBegin,     /* The CREATE token that begins the statement */
+  Token *pName1,     /* The token that holds the name of the view */
+  Token *pName2,     /* The token that holds the name of the view */
+  ExprList *pCNames, /* Optional list of view column names */
+  Select *pSelect,   /* A SELECT statement that will become the new view */
+  int isTemp,        /* TRUE for a TEMPORARY view */
+  int noErr          /* Suppress error messages if VIEW already exists */
+){
+  Table *p;
+  int n;
+  const char *z;
+  Token sEnd;
+  DbFixer sFix;
+  Token *pName = 0;
+  int iDb;
+  sqlite3 *db = pParse->db;
+
+  if( pParse->nVar>0 ){
+    sqlite3ErrorMsg(pParse, "parameters are not allowed in views");
+    goto create_view_fail;
+  }
+  sqlite3StartTable(pParse, pName1, pName2, isTemp, 1, 0, noErr);
+  p = pParse->pNewTable;
+  if( p==0 || pParse->nErr ) goto create_view_fail;
+
+  /* Legacy versions of SQLite allowed the use of the magic "rowid" column
+  ** on a view, even though views do not have rowids.  The following flag
+  ** setting fixes this problem.  But the fix can be disabled by compiling
+  ** with -DSQLITE_ALLOW_ROWID_IN_VIEW in case there are legacy apps that
+  ** depend upon the old buggy behavior.  The ability can also be toggled
+  ** using sqlite3_config(SQLITE_CONFIG_ROWID_IN_VIEW,...) */
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  p->tabFlags |= sqlite3Config.mNoVisibleRowid; /* Optional. Allow by default */
+#else
+  p->tabFlags |= TF_NoVisibleRowid;             /* Never allow rowid in view */
+#endif
+
+  sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+  iDb = sqlite3SchemaToIndex(db, p->pSchema);
+  sqlite3FixInit(&sFix, pParse, iDb, "view", pName);
+  if( sqlite3FixSelect(&sFix, pSelect) ) goto create_view_fail;
+
+  /* Make a copy of the entire SELECT statement that defines the view.
+  ** This will force all the Expr.token.z values to be dynamically
+  ** allocated rather than point to the input string - which means that
+  ** they will persist after the current sqlite3_exec() call returns.
+  */
+  pSelect->selFlags |= SF_View;
+  if( IN_RENAME_OBJECT ){
+    p->u.view.pSelect = pSelect;
+    pSelect = 0;
+  }else{
+    p->u.view.pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
+  }
+  p->pCheck = sqlite3ExprListDup(db, pCNames, EXPRDUP_REDUCE);
+  p->eTabType = TABTYP_VIEW;
+  if( db->mallocFailed ) goto create_view_fail;
+
+  /* Locate the end of the CREATE VIEW statement.  Make sEnd point to
+  ** the end.
+  */
+  sEnd = pParse->sLastToken;
+  assert( sEnd.z[0]!=0 || sEnd.n==0 );
+  if( sEnd.z[0]!=';' ){
+    sEnd.z += sEnd.n;
+  }
+  sEnd.n = 0;
+  n = (int)(sEnd.z - pBegin->z);
+  assert( n>0 );
+  z = pBegin->z;
+  while( sqlite3Isspace(z[n-1]) ){ n--; }
+  sEnd.z = &z[n-1];
+  sEnd.n = 1;
+
+  /* Use sqlite3EndTable() to add the view to the schema table */
+  sqlite3EndTable(pParse, 0, &sEnd, 0, 0);
+
+create_view_fail:
+  sqlite3SelectDelete(db, pSelect);
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameExprlistUnmap(pParse, pCNames);
+  }
+  sqlite3ExprListDelete(db, pCNames);
+  return;
+}
+#endif /* SQLITE_OMIT_VIEW */
+
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+/*
+** The Table structure pTable is really a VIEW.  Fill in the names of
+** the columns of the view in the pTable structure.  Return non-zero if
+** there are errors.  If an error is seen an error message is left
+** in pParse->zErrMsg.
+*/
+static SQLITE_NOINLINE int viewGetColumnNames(Parse *pParse, Table *pTable){
+  Table *pSelTab;   /* A fake table from which we get the result set */
+  Select *pSel;     /* Copy of the SELECT that implements the view */
+  int nErr = 0;     /* Number of errors encountered */
+  sqlite3 *db = pParse->db;  /* Database connection for malloc errors */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  int rc;
+#endif
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth;       /* Saved xAuth pointer */
+#endif
+
+  assert( pTable );
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTable) ){
+    db->nSchemaLock++;
+    rc = sqlite3VtabCallConnect(pParse, pTable);
+    db->nSchemaLock--;
+    return rc;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_VIEW
+  /* A positive nCol means the columns names for this view are
+  ** already known.  This routine is not called unless either the
+  ** table is virtual or nCol is zero.
+  */
+  assert( pTable->nCol<=0 );
+
+  /* A negative nCol is a special marker meaning that we are currently
+  ** trying to compute the column names.  If we enter this routine with
+  ** a negative nCol, it means two or more views form a loop, like this:
+  **
+  **     CREATE VIEW one AS SELECT * FROM two;
+  **     CREATE VIEW two AS SELECT * FROM one;
+  **
+  ** Actually, the error above is now caught prior to reaching this point.
+  ** But the following test is still important as it does come up
+  ** in the following:
+  **
+  **     CREATE TABLE main.ex1(a);
+  **     CREATE TEMP VIEW ex1 AS SELECT a FROM ex1;
+  **     SELECT * FROM temp.ex1;
+  */
+  if( pTable->nCol<0 ){
+    sqlite3ErrorMsg(pParse, "view %s is circularly defined", pTable->zName);
+    return 1;
+  }
+  assert( pTable->nCol>=0 );
+
+  /* If we get this far, it means we need to compute the table names.
+  ** Note that the call to sqlite3ResultSetOfSelect() will expand any
+  ** "*" elements in the results set of the view and will assign cursors
+  ** to the elements of the FROM clause.  But we do not want these changes
+  ** to be permanent.  So the computation is done on a copy of the SELECT
+  ** statement that defines the view.
+  */
+  assert( IsView(pTable) );
+  pSel = sqlite3SelectDup(db, pTable->u.view.pSelect, 0);
+  if( pSel ){
+    u8 eParseMode = pParse->eParseMode;
+    int nTab = pParse->nTab;
+    int nSelect = pParse->nSelect;
+    pParse->eParseMode = PARSE_MODE_NORMAL;
+    sqlite3SrcListAssignCursors(pParse, pSel->pSrc);
+    pTable->nCol = -1;
+    DisableLookaside;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    xAuth = db->xAuth;
+    db->xAuth = 0;
+    pSelTab = sqlite3ResultSetOfSelect(pParse, pSel, SQLITE_AFF_NONE);
+    db->xAuth = xAuth;
+#else
+    pSelTab = sqlite3ResultSetOfSelect(pParse, pSel, SQLITE_AFF_NONE);
+#endif
+    pParse->nTab = nTab;
+    pParse->nSelect = nSelect;
+    if( pSelTab==0 ){
+      pTable->nCol = 0;
+      nErr++;
+    }else if( pTable->pCheck ){
+      /* CREATE VIEW name(arglist) AS ...
+      ** The names of the columns in the table are taken from
+      ** arglist which is stored in pTable->pCheck.  The pCheck field
+      ** normally holds CHECK constraints on an ordinary table, but for
+      ** a VIEW it holds the list of column names.
+      */
+      sqlite3ColumnsFromExprList(pParse, pTable->pCheck,
+                                 &pTable->nCol, &pTable->aCol);
+      if( pParse->nErr==0
+       && pTable->nCol==pSel->pEList->nExpr
+      ){
+        assert( db->mallocFailed==0 );
+        sqlite3SubqueryColumnTypes(pParse, pTable, pSel, SQLITE_AFF_NONE);
+      }
+    }else{
+      /* CREATE VIEW name AS...  without an argument list.  Construct
+      ** the column names from the SELECT statement that defines the view.
+      */
+      assert( pTable->aCol==0 );
+      pTable->nCol = pSelTab->nCol;
+      pTable->aCol = pSelTab->aCol;
+      pTable->tabFlags |= (pSelTab->tabFlags & COLFLAG_NOINSERT);
+      pSelTab->nCol = 0;
+      pSelTab->aCol = 0;
+      assert( sqlite3SchemaMutexHeld(db, 0, pTable->pSchema) );
+    }
+    pTable->nNVCol = pTable->nCol;
+    sqlite3DeleteTable(db, pSelTab);
+    sqlite3SelectDelete(db, pSel);
+    EnableLookaside;
+    pParse->eParseMode = eParseMode;
+  } else {
+    nErr++;
+  }
+  pTable->pSchema->schemaFlags |= DB_UnresetViews;
+  if( db->mallocFailed ){
+    sqlite3DeleteColumnNames(db, pTable);
+  }
+#endif /* SQLITE_OMIT_VIEW */
+  return nErr + pParse->nErr;
+}
+SQLITE_PRIVATE int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
+  assert( pTable!=0 );
+  if( !IsVirtual(pTable) && pTable->nCol>0 ) return 0;
+  return viewGetColumnNames(pParse, pTable);
+}
+#endif /* !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE) */
+
+#ifndef SQLITE_OMIT_VIEW
+/*
+** Clear the column names from every VIEW in database idx.
+*/
+static void sqliteViewResetAll(sqlite3 *db, int idx){
+  HashElem *i;
+  assert( sqlite3SchemaMutexHeld(db, idx, 0) );
+  if( !DbHasProperty(db, idx, DB_UnresetViews) ) return;
+  for(i=sqliteHashFirst(&db->aDb[idx].pSchema->tblHash); i;i=sqliteHashNext(i)){
+    Table *pTab = sqliteHashData(i);
+    if( IsView(pTab) ){
+      sqlite3DeleteColumnNames(db, pTab);
+    }
+  }
+  DbClearProperty(db, idx, DB_UnresetViews);
+}
+#else
+# define sqliteViewResetAll(A,B)
+#endif /* SQLITE_OMIT_VIEW */
+
+/*
+** This function is called by the VDBE to adjust the internal schema
+** used by SQLite when the btree layer moves a table root page. The
+** root-page of a table or index in database iDb has changed from iFrom
+** to iTo.
+**
+** Ticket #1728:  The symbol table might still contain information
+** on tables and/or indices that are the process of being deleted.
+** If you are unlucky, one of those deleted indices or tables might
+** have the same rootpage number as the real table or index that is
+** being moved.  So we cannot stop searching after the first match
+** because the first match might be for one of the deleted indices
+** or tables and not the table/index that is actually being moved.
+** We must continue looping until all tables and indices with
+** rootpage==iFrom have been converted to have a rootpage of iTo
+** in order to be certain that we got the right one.
+*/
+#ifndef SQLITE_OMIT_AUTOVACUUM
+SQLITE_PRIVATE void sqlite3RootPageMoved(sqlite3 *db, int iDb, Pgno iFrom, Pgno iTo){
+  HashElem *pElem;
+  Hash *pHash;
+  Db *pDb;
+
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  pDb = &db->aDb[iDb];
+  pHash = &pDb->pSchema->tblHash;
+  for(pElem=sqliteHashFirst(pHash); pElem; pElem=sqliteHashNext(pElem)){
+    Table *pTab = sqliteHashData(pElem);
+    if( pTab->tnum==iFrom ){
+      pTab->tnum = iTo;
+    }
+  }
+  pHash = &pDb->pSchema->idxHash;
+  for(pElem=sqliteHashFirst(pHash); pElem; pElem=sqliteHashNext(pElem)){
+    Index *pIdx = sqliteHashData(pElem);
+    if( pIdx->tnum==iFrom ){
+      pIdx->tnum = iTo;
+    }
+  }
+}
+#endif
+
+/*
+** Write code to erase the table with root-page iTable from database iDb.
+** Also write code to modify the sqlite_schema table and internal schema
+** if a root-page of another table is moved by the btree-layer whilst
+** erasing iTable (this can happen with an auto-vacuum database).
+*/
+static void destroyRootPage(Parse *pParse, int iTable, int iDb){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int r1 = sqlite3GetTempReg(pParse);
+  if( iTable<2 ) sqlite3ErrorMsg(pParse, "corrupt schema");
+  sqlite3VdbeAddOp3(v, OP_Destroy, iTable, r1, iDb);
+  sqlite3MayAbort(pParse);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  /* OP_Destroy stores an in integer r1. If this integer
+  ** is non-zero, then it is the root page number of a table moved to
+  ** location iTable. The following code modifies the sqlite_schema table to
+  ** reflect this.
+  **
+  ** The "#NNN" in the SQL is a special constant that means whatever value
+  ** is in register NNN.  See grammar rules associated with the TK_REGISTER
+  ** token for additional information.
+  */
+  sqlite3NestedParse(pParse,
+     "UPDATE %Q." LEGACY_SCHEMA_TABLE
+     " SET rootpage=%d WHERE #%d AND rootpage=#%d",
+     pParse->db->aDb[iDb].zDbSName, iTable, r1, r1);
+#endif
+  sqlite3ReleaseTempReg(pParse, r1);
+}
+
+/*
+** Write VDBE code to erase table pTab and all associated indices on disk.
+** Code to update the sqlite_schema tables and internal schema definitions
+** in case a root-page belonging to another table is moved by the btree layer
+** is also added (this can happen with an auto-vacuum database).
+*/
+static void destroyTable(Parse *pParse, Table *pTab){
+  /* If the database may be auto-vacuum capable (if SQLITE_OMIT_AUTOVACUUM
+  ** is not defined), then it is important to call OP_Destroy on the
+  ** table and index root-pages in order, starting with the numerically
+  ** largest root-page number. This guarantees that none of the root-pages
+  ** to be destroyed is relocated by an earlier OP_Destroy. i.e. if the
+  ** following were coded:
+  **
+  ** OP_Destroy 4 0
+  ** ...
+  ** OP_Destroy 5 0
+  **
+  ** and root page 5 happened to be the largest root-page number in the
+  ** database, then root page 5 would be moved to page 4 by the
+  ** "OP_Destroy 4 0" opcode. The subsequent "OP_Destroy 5 0" would hit
+  ** a free-list page.
+  */
+  Pgno iTab = pTab->tnum;
+  Pgno iDestroyed = 0;
+
+  while( 1 ){
+    Index *pIdx;
+    Pgno iLargest = 0;
+
+    if( iDestroyed==0 || iTab<iDestroyed ){
+      iLargest = iTab;
+    }
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      Pgno iIdx = pIdx->tnum;
+      assert( pIdx->pSchema==pTab->pSchema );
+      if( (iDestroyed==0 || (iIdx<iDestroyed)) && iIdx>iLargest ){
+        iLargest = iIdx;
+      }
+    }
+    if( iLargest==0 ){
+      return;
+    }else{
+      int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+      assert( iDb>=0 && iDb<pParse->db->nDb );
+      destroyRootPage(pParse, iLargest, iDb);
+      iDestroyed = iLargest;
+    }
+  }
+}
+
+/*
+** Remove entries from the sqlite_statN tables (for N in (1,2,3))
+** after a DROP INDEX or DROP TABLE command.
+*/
+static void sqlite3ClearStatTables(
+  Parse *pParse,         /* The parsing context */
+  int iDb,               /* The database number */
+  const char *zType,     /* "idx" or "tbl" */
+  const char *zName      /* Name of index or table */
+){
+  int i;
+  const char *zDbName = pParse->db->aDb[iDb].zDbSName;
+  for(i=1; i<=4; i++){
+    char zTab[24];
+    sqlite3_snprintf(sizeof(zTab),zTab,"sqlite_stat%d",i);
+    if( sqlite3FindTable(pParse->db, zTab, zDbName) ){
+      sqlite3NestedParse(pParse,
+        "DELETE FROM %Q.%s WHERE %s=%Q",
+        zDbName, zTab, zType, zName
+      );
+    }
+  }
+}
+
+/*
+** Generate code to drop a table.
+*/
+SQLITE_PRIVATE void sqlite3CodeDropTable(Parse *pParse, Table *pTab, int iDb, int isView){
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  Trigger *pTrigger;
+  Db *pDb = &db->aDb[iDb];
+
+  v = sqlite3GetVdbe(pParse);
+  assert( v!=0 );
+  sqlite3BeginWriteOperation(pParse, 1, iDb);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    sqlite3VdbeAddOp0(v, OP_VBegin);
+  }
+#endif
+
+  /* Drop all triggers associated with the table being dropped. Code
+  ** is generated to remove entries from sqlite_schema and/or
+  ** sqlite_temp_schema if required.
+  */
+  pTrigger = sqlite3TriggerList(pParse, pTab);
+  while( pTrigger ){
+    assert( pTrigger->pSchema==pTab->pSchema ||
+        pTrigger->pSchema==db->aDb[1].pSchema );
+    sqlite3DropTriggerPtr(pParse, pTrigger);
+    pTrigger = pTrigger->pNext;
+  }
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+  /* Remove any entries of the sqlite_sequence table associated with
+  ** the table being dropped. This is done before the table is dropped
+  ** at the btree level, in case the sqlite_sequence table needs to
+  ** move as a result of the drop (can happen in auto-vacuum mode).
+  */
+  if( pTab->tabFlags & TF_Autoincrement ){
+    sqlite3NestedParse(pParse,
+      "DELETE FROM %Q.sqlite_sequence WHERE name=%Q",
+      pDb->zDbSName, pTab->zName
+    );
+  }
+#endif
+
+  /* Drop all entries in the schema table that refer to the
+  ** table. The program name loops through the schema table and deletes
+  ** every row that refers to a table of the same name as the one being
+  ** dropped. Triggers are handled separately because a trigger can be
+  ** created in the temp database that refers to a table in another
+  ** database.
+  */
+  sqlite3NestedParse(pParse,
+      "DELETE FROM %Q." LEGACY_SCHEMA_TABLE
+      " WHERE tbl_name=%Q and type!='trigger'",
+      pDb->zDbSName, pTab->zName);
+  if( !isView && !IsVirtual(pTab) ){
+    destroyTable(pParse, pTab);
+  }
+
+  /* Remove the table entry from SQLite's internal schema and modify
+  ** the schema cookie.
+  */
+  if( IsVirtual(pTab) ){
+    sqlite3VdbeAddOp4(v, OP_VDestroy, iDb, 0, 0, pTab->zName, 0);
+    sqlite3MayAbort(pParse);
+  }
+  sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);
+  sqlite3ChangeCookie(pParse, iDb);
+  sqliteViewResetAll(db, iDb);
+}
+
+/*
+** Return TRUE if shadow tables should be read-only in the current
+** context.
+*/
+SQLITE_PRIVATE int sqlite3ReadOnlyShadowTables(sqlite3 *db){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( (db->flags & SQLITE_Defensive)!=0
+   && db->pVtabCtx==0
+   && db->nVdbeExec==0
+   && !sqlite3VtabInSync(db)
+  ){
+    return 1;
+  }
+#endif
+  return 0;
+}
+
+/*
+** Return true if it is not allowed to drop the given table
+*/
+static int tableMayNotBeDropped(sqlite3 *db, Table *pTab){
+  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
+    if( sqlite3StrNICmp(pTab->zName+7, "stat", 4)==0 ) return 0;
+    if( sqlite3StrNICmp(pTab->zName+7, "parameters", 10)==0 ) return 0;
+    return 1;
+  }
+  if( (pTab->tabFlags & TF_Shadow)!=0 && sqlite3ReadOnlyShadowTables(db) ){
+    return 1;
+  }
+  if( pTab->tabFlags & TF_Eponymous ){
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** This routine is called to do the work of a DROP TABLE statement.
+** pName is the name of the table to be dropped.
+*/
+SQLITE_PRIVATE void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
+  Table *pTab;
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  if( db->mallocFailed ){
+    goto exit_drop_table;
+  }
+  assert( pParse->nErr==0 );
+  assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 );
+  assert( pName->a[0].fg.isSubquery==0 );
+  if( sqlite3ReadSchema(pParse) ) goto exit_drop_table;
+  if( noErr ) db->suppressErr++;
+  assert( isView==0 || isView==LOCATE_VIEW );
+  pTab = sqlite3LocateTableItem(pParse, isView, &pName->a[0]);
+  if( noErr ) db->suppressErr--;
+
+  if( pTab==0 ){
+    if( noErr ){
+      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].u4.zDatabase);
+      sqlite3ForceNotReadOnly(pParse);
+    }
+    goto exit_drop_table;
+  }
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+
+  /* If pTab is a virtual table, call ViewGetColumnNames() to ensure
+  ** it is initialized.
+  */
+  if( IsVirtual(pTab) && sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto exit_drop_table;
+  }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  {
+    int code;
+    const char *zTab = SCHEMA_TABLE(iDb);
+    const char *zDb = db->aDb[iDb].zDbSName;
+    const char *zArg2 = 0;
+    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb)){
+      goto exit_drop_table;
+    }
+    if( isView ){
+      if( !OMIT_TEMPDB && iDb==1 ){
+        code = SQLITE_DROP_TEMP_VIEW;
+      }else{
+        code = SQLITE_DROP_VIEW;
+      }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    }else if( IsVirtual(pTab) ){
+      code = SQLITE_DROP_VTABLE;
+      zArg2 = sqlite3GetVTable(db, pTab)->pMod->zName;
+#endif
+    }else{
+      if( !OMIT_TEMPDB && iDb==1 ){
+        code = SQLITE_DROP_TEMP_TABLE;
+      }else{
+        code = SQLITE_DROP_TABLE;
+      }
+    }
+    if( sqlite3AuthCheck(pParse, code, pTab->zName, zArg2, zDb) ){
+      goto exit_drop_table;
+    }
+    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb) ){
+      goto exit_drop_table;
+    }
+  }
+#endif
+  if( tableMayNotBeDropped(db, pTab) ){
+    sqlite3ErrorMsg(pParse, "table %s may not be dropped", pTab->zName);
+    goto exit_drop_table;
+  }
+
+#ifndef SQLITE_OMIT_VIEW
+  /* Ensure DROP TABLE is not used on a view, and DROP VIEW is not used
+  ** on a table.
+  */
+  if( isView && !IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "use DROP TABLE to delete table %s", pTab->zName);
+    goto exit_drop_table;
+  }
+  if( !isView && IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "use DROP VIEW to delete view %s", pTab->zName);
+    goto exit_drop_table;
+  }
+#endif
+
+  /* Generate code to remove the table from the schema table
+  ** on disk.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3BeginWriteOperation(pParse, 1, iDb);
+    if( !isView ){
+      sqlite3ClearStatTables(pParse, iDb, "tbl", pTab->zName);
+      sqlite3FkDropTable(pParse, pName, pTab);
+    }
+    sqlite3CodeDropTable(pParse, pTab, iDb, isView);
+  }
+
+exit_drop_table:
+  sqlite3SrcListDelete(db, pName);
+}
+
+/*
+** This routine is called to create a new foreign key on the table
+** currently under construction.  pFromCol determines which columns
+** in the current table point to the foreign key.  If pFromCol==0 then
+** connect the key to the last column inserted.  pTo is the name of
+** the table referred to (a.k.a the "parent" table).  pToCol is a list
+** of tables in the parent pTo table.  flags contains all
+** information about the conflict resolution algorithms specified
+** in the ON DELETE, ON UPDATE and ON INSERT clauses.
+**
+** An FKey structure is created and added to the table currently
+** under construction in the pParse->pNewTable field.
+**
+** The foreign key is set for IMMEDIATE processing.  A subsequent call
+** to sqlite3DeferForeignKey() might change this to DEFERRED.
+*/
+SQLITE_PRIVATE void sqlite3CreateForeignKey(
+  Parse *pParse,       /* Parsing context */
+  ExprList *pFromCol,  /* Columns in this table that point to other table */
+  Token *pTo,          /* Name of the other table */
+  ExprList *pToCol,    /* Columns in the other table */
+  int flags            /* Conflict resolution algorithms. */
+){
+  sqlite3 *db = pParse->db;
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  FKey *pFKey = 0;
+  FKey *pNextTo;
+  Table *p = pParse->pNewTable;
+  i64 nByte;
+  int i;
+  int nCol;
+  char *z;
+
+  assert( pTo!=0 );
+  if( p==0 || IN_DECLARE_VTAB ) goto fk_end;
+  if( pFromCol==0 ){
+    int iCol = p->nCol-1;
+    if( NEVER(iCol<0) ) goto fk_end;
+    if( pToCol && pToCol->nExpr!=1 ){
+      sqlite3ErrorMsg(pParse, "foreign key on %s"
+         " should reference only one column of table %T",
+         p->aCol[iCol].zCnName, pTo);
+      goto fk_end;
+    }
+    nCol = 1;
+  }else if( pToCol && pToCol->nExpr!=pFromCol->nExpr ){
+    sqlite3ErrorMsg(pParse,
+        "number of columns in foreign key does not match the number of "
+        "columns in the referenced table");
+    goto fk_end;
+  }else{
+    nCol = pFromCol->nExpr;
+  }
+  nByte = sizeof(*pFKey) + (nCol-1)*sizeof(pFKey->aCol[0]) + pTo->n + 1;
+  if( pToCol ){
+    for(i=0; i<pToCol->nExpr; i++){
+      nByte += sqlite3Strlen30(pToCol->a[i].zEName) + 1;
+    }
+  }
+  pFKey = sqlite3DbMallocZero(db, nByte );
+  if( pFKey==0 ){
+    goto fk_end;
+  }
+  pFKey->pFrom = p;
+  assert( IsOrdinaryTable(p) );
+  pFKey->pNextFrom = p->u.tab.pFKey;
+  z = (char*)&pFKey->aCol[nCol];
+  pFKey->zTo = z;
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameTokenMap(pParse, (void*)z, pTo);
+  }
+  memcpy(z, pTo->z, pTo->n);
+  z[pTo->n] = 0;
+  sqlite3Dequote(z);
+  z += pTo->n+1;
+  pFKey->nCol = nCol;
+  if( pFromCol==0 ){
+    pFKey->aCol[0].iFrom = p->nCol-1;
+  }else{
+    for(i=0; i<nCol; i++){
+      int j;
+      for(j=0; j<p->nCol; j++){
+        if( sqlite3StrICmp(p->aCol[j].zCnName, pFromCol->a[i].zEName)==0 ){
+          pFKey->aCol[i].iFrom = j;
+          break;
+        }
+      }
+      if( j>=p->nCol ){
+        sqlite3ErrorMsg(pParse,
+          "unknown column \"%s\" in foreign key definition",
+          pFromCol->a[i].zEName);
+        goto fk_end;
+      }
+      if( IN_RENAME_OBJECT ){
+        sqlite3RenameTokenRemap(pParse, &pFKey->aCol[i], pFromCol->a[i].zEName);
+      }
+    }
+  }
+  if( pToCol ){
+    for(i=0; i<nCol; i++){
+      int n = sqlite3Strlen30(pToCol->a[i].zEName);
+      pFKey->aCol[i].zCol = z;
+      if( IN_RENAME_OBJECT ){
+        sqlite3RenameTokenRemap(pParse, z, pToCol->a[i].zEName);
+      }
+      memcpy(z, pToCol->a[i].zEName, n);
+      z[n] = 0;
+      z += n+1;
+    }
+  }
+  pFKey->isDeferred = 0;
+  pFKey->aAction[0] = (u8)(flags & 0xff);            /* ON DELETE action */
+  pFKey->aAction[1] = (u8)((flags >> 8 ) & 0xff);    /* ON UPDATE action */
+
+  assert( sqlite3SchemaMutexHeld(db, 0, p->pSchema) );
+  pNextTo = (FKey *)sqlite3HashInsert(&p->pSchema->fkeyHash,
+      pFKey->zTo, (void *)pFKey
+  );
+  if( pNextTo==pFKey ){
+    sqlite3OomFault(db);
+    goto fk_end;
+  }
+  if( pNextTo ){
+    assert( pNextTo->pPrevTo==0 );
+    pFKey->pNextTo = pNextTo;
+    pNextTo->pPrevTo = pFKey;
+  }
+
+  /* Link the foreign key to the table as the last step.
+  */
+  assert( IsOrdinaryTable(p) );
+  p->u.tab.pFKey = pFKey;
+  pFKey = 0;
+
+fk_end:
+  sqlite3DbFree(db, pFKey);
+#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */
+  sqlite3ExprListDelete(db, pFromCol);
+  sqlite3ExprListDelete(db, pToCol);
+}
+
+/*
+** This routine is called when an INITIALLY IMMEDIATE or INITIALLY DEFERRED
+** clause is seen as part of a foreign key definition.  The isDeferred
+** parameter is 1 for INITIALLY DEFERRED and 0 for INITIALLY IMMEDIATE.
+** The behavior of the most recently created foreign key is adjusted
+** accordingly.
+*/
+SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse *pParse, int isDeferred){
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  Table *pTab;
+  FKey *pFKey;
+  if( (pTab = pParse->pNewTable)==0 ) return;
+  if( NEVER(!IsOrdinaryTable(pTab)) ) return;
+  if( (pFKey = pTab->u.tab.pFKey)==0 ) return;
+  assert( isDeferred==0 || isDeferred==1 ); /* EV: R-30323-21917 */
+  pFKey->isDeferred = (u8)isDeferred;
+#endif
+}
+
+/*
+** Generate code that will erase and refill index *pIdx.  This is
+** used to initialize a newly created index or to recompute the
+** content of an index in response to a REINDEX command.
+**
+** if memRootPage is not negative, it means that the index is newly
+** created.  The register specified by memRootPage contains the
+** root page number of the index.  If memRootPage is negative, then
+** the index already exists and must be cleared before being refilled and
+** the root page number of the index is taken from pIndex->tnum.
+*/
+static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
+  Table *pTab = pIndex->pTable;  /* The table that is indexed */
+  int iTab = pParse->nTab++;     /* Btree cursor used for pTab */
+  int iIdx = pParse->nTab++;     /* Btree cursor used for pIndex */
+  int iSorter;                   /* Cursor opened by OpenSorter (if in use) */
+  int addr1;                     /* Address of top of loop */
+  int addr2;                     /* Address to jump to for next iteration */
+  Pgno tnum;                     /* Root page of index */
+  int iPartIdxLabel;             /* Jump to this label to skip a row */
+  Vdbe *v;                       /* Generate code into this virtual machine */
+  KeyInfo *pKey;                 /* KeyInfo for index */
+  int regRecord;                 /* Register holding assembled index record */
+  sqlite3 *db = pParse->db;      /* The database connection */
+  int iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( sqlite3AuthCheck(pParse, SQLITE_REINDEX, pIndex->zName, 0,
+      db->aDb[iDb].zDbSName ) ){
+    return;
+  }
+#endif
+
+  /* Require a write-lock on the table to perform this operation */
+  sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName);
+
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) return;
+  if( memRootPage>=0 ){
+    tnum = (Pgno)memRootPage;
+  }else{
+    tnum = pIndex->tnum;
+  }
+  pKey = sqlite3KeyInfoOfIndex(pParse, pIndex);
+  assert( pKey!=0 || pParse->nErr );
+
+  /* Open the sorter cursor if we are to use one. */
+  iSorter = pParse->nTab++;
+  sqlite3VdbeAddOp4(v, OP_SorterOpen, iSorter, 0, pIndex->nKeyCol, (char*)
+                    sqlite3KeyInfoRef(pKey), P4_KEYINFO);
+
+  /* Open the table. Loop through all rows of the table, inserting index
+  ** records into the sorter. */
+  sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
+  addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0); VdbeCoverage(v);
+  regRecord = sqlite3GetTempReg(pParse);
+  sqlite3MultiWrite(pParse);
+
+  sqlite3GenerateIndexKey(pParse,pIndex,iTab,regRecord,0,&iPartIdxLabel,0,0);
+  sqlite3VdbeAddOp2(v, OP_SorterInsert, iSorter, regRecord);
+  sqlite3ResolvePartIdxLabel(pParse, iPartIdxLabel);
+  sqlite3VdbeAddOp2(v, OP_Next, iTab, addr1+1); VdbeCoverage(v);
+  sqlite3VdbeJumpHere(v, addr1);
+  if( memRootPage<0 ) sqlite3VdbeAddOp2(v, OP_Clear, tnum, iDb);
+  sqlite3VdbeAddOp4(v, OP_OpenWrite, iIdx, (int)tnum, iDb,
+                    (char *)pKey, P4_KEYINFO);
+  sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR|((memRootPage>=0)?OPFLAG_P2ISREG:0));
+
+  addr1 = sqlite3VdbeAddOp2(v, OP_SorterSort, iSorter, 0); VdbeCoverage(v);
+  if( IsUniqueIndex(pIndex) ){
+    int j2 = sqlite3VdbeGoto(v, 1);
+    addr2 = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeVerifyAbortable(v, OE_Abort);
+    sqlite3VdbeAddOp4Int(v, OP_SorterCompare, iSorter, j2, regRecord,
+                         pIndex->nKeyCol); VdbeCoverage(v);
+    sqlite3UniqueConstraint(pParse, OE_Abort, pIndex);
+    sqlite3VdbeJumpHere(v, j2);
+  }else{
+    /* Most CREATE INDEX and REINDEX statements that are not UNIQUE can not
+    ** abort. The exception is if one of the indexed expressions contains a
+    ** user function that throws an exception when it is evaluated. But the
+    ** overhead of adding a statement journal to a CREATE INDEX statement is
+    ** very small (since most of the pages written do not contain content that
+    ** needs to be restored if the statement aborts), so we call
+    ** sqlite3MayAbort() for all CREATE INDEX statements.  */
+    sqlite3MayAbort(pParse);
+    addr2 = sqlite3VdbeCurrentAddr(v);
+  }
+  sqlite3VdbeAddOp3(v, OP_SorterData, iSorter, regRecord, iIdx);
+  if( !pIndex->bAscKeyBug ){
+    /* This OP_SeekEnd opcode makes index insert for a REINDEX go much
+    ** faster by avoiding unnecessary seeks.  But the optimization does
+    ** not work for UNIQUE constraint indexes on WITHOUT ROWID tables
+    ** with DESC primary keys, since those indexes have there keys in
+    ** a different order from the main table.
+    ** See ticket: https://www.sqlite.org/src/info/bba7b69f9849b5bf
+    */
+    sqlite3VdbeAddOp1(v, OP_SeekEnd, iIdx);
+  }
+  sqlite3VdbeAddOp2(v, OP_IdxInsert, iIdx, regRecord);
+  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+  sqlite3ReleaseTempReg(pParse, regRecord);
+  sqlite3VdbeAddOp2(v, OP_SorterNext, iSorter, addr2); VdbeCoverage(v);
+  sqlite3VdbeJumpHere(v, addr1);
+
+  sqlite3VdbeAddOp1(v, OP_Close, iTab);
+  sqlite3VdbeAddOp1(v, OP_Close, iIdx);
+  sqlite3VdbeAddOp1(v, OP_Close, iSorter);
+}
+
+/*
+** Allocate heap space to hold an Index object with nCol columns.
+**
+** Increase the allocation size to provide an extra nExtra bytes
+** of 8-byte aligned space after the Index object and return a
+** pointer to this extra space in *ppExtra.
+*/
+SQLITE_PRIVATE Index *sqlite3AllocateIndexObject(
+  sqlite3 *db,         /* Database connection */
+  i16 nCol,            /* Total number of columns in the index */
+  int nExtra,          /* Number of bytes of extra space to alloc */
+  char **ppExtra       /* Pointer to the "extra" space */
+){
+  Index *p;            /* Allocated index object */
+  int nByte;           /* Bytes of space for Index object + arrays */
+
+  nByte = ROUND8(sizeof(Index)) +              /* Index structure  */
+          ROUND8(sizeof(char*)*nCol) +         /* Index.azColl     */
+          ROUND8(sizeof(LogEst)*(nCol+1) +     /* Index.aiRowLogEst   */
+                 sizeof(i16)*nCol +            /* Index.aiColumn   */
+                 sizeof(u8)*nCol);             /* Index.aSortOrder */
+  p = sqlite3DbMallocZero(db, nByte + nExtra);
+  if( p ){
+    char *pExtra = ((char*)p)+ROUND8(sizeof(Index));
+    p->azColl = (const char**)pExtra; pExtra += ROUND8(sizeof(char*)*nCol);
+    p->aiRowLogEst = (LogEst*)pExtra; pExtra += sizeof(LogEst)*(nCol+1);
+    p->aiColumn = (i16*)pExtra;       pExtra += sizeof(i16)*nCol;
+    p->aSortOrder = (u8*)pExtra;
+    p->nColumn = nCol;
+    p->nKeyCol = nCol - 1;
+    *ppExtra = ((char*)p) + nByte;
+  }
+  return p;
+}
+
+/*
+** If expression list pList contains an expression that was parsed with
+** an explicit "NULLS FIRST" or "NULLS LAST" clause, leave an error in
+** pParse and return non-zero. Otherwise, return zero.
+*/
+SQLITE_PRIVATE int sqlite3HasExplicitNulls(Parse *pParse, ExprList *pList){
+  if( pList ){
+    int i;
+    for(i=0; i<pList->nExpr; i++){
+      if( pList->a[i].fg.bNulls ){
+        u8 sf = pList->a[i].fg.sortFlags;
+        sqlite3ErrorMsg(pParse, "unsupported use of NULLS %s",
+            (sf==0 || sf==3) ? "FIRST" : "LAST"
+        );
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Create a new index for an SQL table.  pName1.pName2 is the name of the index
+** and pTblList is the name of the table that is to be indexed.  Both will
+** be NULL for a primary key or an index that is created to satisfy a
+** UNIQUE constraint.  If pTable and pIndex are NULL, use pParse->pNewTable
+** as the table to be indexed.  pParse->pNewTable is a table that is
+** currently being constructed by a CREATE TABLE statement.
+**
+** pList is a list of columns to be indexed.  pList will be NULL if this
+** is a primary key or unique-constraint on the most recent column added
+** to the table currently under construction.
+*/
+SQLITE_PRIVATE void sqlite3CreateIndex(
+  Parse *pParse,     /* All information about this parse */
+  Token *pName1,     /* First part of index name. May be NULL */
+  Token *pName2,     /* Second part of index name. May be NULL */
+  SrcList *pTblName, /* Table to index. Use pParse->pNewTable if 0 */
+  ExprList *pList,   /* A list of columns to be indexed */
+  int onError,       /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
+  Token *pStart,     /* The CREATE token that begins this statement */
+  Expr *pPIWhere,    /* WHERE clause for partial indices */
+  int sortOrder,     /* Sort order of primary key when pList==NULL */
+  int ifNotExist,    /* Omit error if index already exists */
+  u8 idxType         /* The index type */
+){
+  Table *pTab = 0;     /* Table to be indexed */
+  Index *pIndex = 0;   /* The index to be created */
+  char *zName = 0;     /* Name of the index */
+  int nName;           /* Number of characters in zName */
+  int i, j;
+  DbFixer sFix;        /* For assigning database names to pTable */
+  int sortOrderMask;   /* 1 to honor DESC in index.  0 to ignore. */
+  sqlite3 *db = pParse->db;
+  Db *pDb;             /* The specific table containing the indexed database */
+  int iDb;             /* Index of the database that is being written */
+  Token *pName = 0;    /* Unqualified name of the index to create */
+  struct ExprList_item *pListItem; /* For looping over pList */
+  int nExtra = 0;                  /* Space allocated for zExtra[] */
+  int nExtraCol;                   /* Number of extra columns needed */
+  char *zExtra = 0;                /* Extra space after the Index object */
+  Index *pPk = 0;      /* PRIMARY KEY index for WITHOUT ROWID tables */
+
+  assert( db->pParse==pParse );
+  if( pParse->nErr ){
+    goto exit_create_index;
+  }
+  assert( db->mallocFailed==0 );
+  if( IN_DECLARE_VTAB && idxType!=SQLITE_IDXTYPE_PRIMARYKEY ){
+    goto exit_create_index;
+  }
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    goto exit_create_index;
+  }
+  if( sqlite3HasExplicitNulls(pParse, pList) ){
+    goto exit_create_index;
+  }
+
+  /*
+  ** Find the table that is to be indexed.  Return early if not found.
+  */
+  if( pTblName!=0 ){
+
+    /* Use the two-part index name to determine the database
+    ** to search for the table. 'Fix' the table name to this db
+    ** before looking up the table.
+    */
+    assert( pName1 && pName2 );
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+    if( iDb<0 ) goto exit_create_index;
+    assert( pName && pName->z );
+
+#ifndef SQLITE_OMIT_TEMPDB
+    /* If the index name was unqualified, check if the table
+    ** is a temp table. If so, set the database to 1. Do not do this
+    ** if initializing a database schema.
+    */
+    if( !db->init.busy ){
+      pTab = sqlite3SrcListLookup(pParse, pTblName);
+      if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
+        iDb = 1;
+      }
+    }
+#endif
+
+    sqlite3FixInit(&sFix, pParse, iDb, "index", pName);
+    if( sqlite3FixSrcList(&sFix, pTblName) ){
+      /* Because the parser constructs pTblName from a single identifier,
+      ** sqlite3FixSrcList can never fail. */
+      assert(0);
+    }
+    pTab = sqlite3LocateTableItem(pParse, 0, &pTblName->a[0]);
+    assert( db->mallocFailed==0 || pTab==0 );
+    if( pTab==0 ) goto exit_create_index;
+    if( iDb==1 && db->aDb[iDb].pSchema!=pTab->pSchema ){
+      sqlite3ErrorMsg(pParse,
+           "cannot create a TEMP index on non-TEMP table \"%s\"",
+           pTab->zName);
+      goto exit_create_index;
+    }
+    if( !HasRowid(pTab) ) pPk = sqlite3PrimaryKeyIndex(pTab);
+  }else{
+    assert( pName==0 );
+    assert( pStart==0 );
+    pTab = pParse->pNewTable;
+    if( !pTab ) goto exit_create_index;
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  }
+  pDb = &db->aDb[iDb];
+
+  assert( pTab!=0 );
+  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0
+       && db->init.busy==0
+       && pTblName!=0
+  ){
+    sqlite3ErrorMsg(pParse, "table %s may not be indexed", pTab->zName);
+    goto exit_create_index;
+  }
+#ifndef SQLITE_OMIT_VIEW
+  if( IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "views may not be indexed");
+    goto exit_create_index;
+  }
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    sqlite3ErrorMsg(pParse, "virtual tables may not be indexed");
+    goto exit_create_index;
+  }
+#endif
+
+  /*
+  ** Find the name of the index.  Make sure there is not already another
+  ** index or table with the same name.
+  **
+  ** Exception:  If we are reading the names of permanent indices from the
+  ** sqlite_schema table (because some other process changed the schema) and
+  ** one of the index names collides with the name of a temporary table or
+  ** index, then we will continue to process this index.
+  **
+  ** If pName==0 it means that we are
+  ** dealing with a primary key or UNIQUE constraint.  We have to invent our
+  ** own name.
+  */
+  if( pName ){
+    zName = sqlite3NameFromToken(db, pName);
+    if( zName==0 ) goto exit_create_index;
+    assert( pName->z!=0 );
+    if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName,"index",pTab->zName) ){
+      goto exit_create_index;
+    }
+    if( !IN_RENAME_OBJECT ){
+      if( !db->init.busy ){
+        if( sqlite3FindTable(db, zName, pDb->zDbSName)!=0 ){
+          sqlite3ErrorMsg(pParse, "there is already a table named %s", zName);
+          goto exit_create_index;
+        }
+      }
+      if( sqlite3FindIndex(db, zName, pDb->zDbSName)!=0 ){
+        if( !ifNotExist ){
+          sqlite3ErrorMsg(pParse, "index %s already exists", zName);
+        }else{
+          assert( !db->init.busy );
+          sqlite3CodeVerifySchema(pParse, iDb);
+          sqlite3ForceNotReadOnly(pParse);
+        }
+        goto exit_create_index;
+      }
+    }
+  }else{
+    int n;
+    Index *pLoop;
+    for(pLoop=pTab->pIndex, n=1; pLoop; pLoop=pLoop->pNext, n++){}
+    zName = sqlite3MPrintf(db, "sqlite_autoindex_%s_%d", pTab->zName, n);
+    if( zName==0 ){
+      goto exit_create_index;
+    }
+
+    /* Automatic index names generated from within sqlite3_declare_vtab()
+    ** must have names that are distinct from normal automatic index names.
+    ** The following statement converts "sqlite3_autoindex..." into
+    ** "sqlite3_butoindex..." in order to make the names distinct.
+    ** The "vtab_err.test" test demonstrates the need of this statement. */
+    if( IN_SPECIAL_PARSE ) zName[7]++;
+  }
+
+  /* Check for authorization to create an index.
+  */
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( !IN_RENAME_OBJECT ){
+    const char *zDb = pDb->zDbSName;
+    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iDb), 0, zDb) ){
+      goto exit_create_index;
+    }
+    i = SQLITE_CREATE_INDEX;
+    if( !OMIT_TEMPDB && iDb==1 ) i = SQLITE_CREATE_TEMP_INDEX;
+    if( sqlite3AuthCheck(pParse, i, zName, pTab->zName, zDb) ){
+      goto exit_create_index;
+    }
+  }
+#endif
+
+  /* If pList==0, it means this routine was called to make a primary
+  ** key out of the last column added to the table under construction.
+  ** So create a fake list to simulate this.
+  */
+  if( pList==0 ){
+    Token prevCol;
+    Column *pCol = &pTab->aCol[pTab->nCol-1];
+    pCol->colFlags |= COLFLAG_UNIQUE;
+    sqlite3TokenInit(&prevCol, pCol->zCnName);
+    pList = sqlite3ExprListAppend(pParse, 0,
+              sqlite3ExprAlloc(db, TK_ID, &prevCol, 0));
+    if( pList==0 ) goto exit_create_index;
+    assert( pList->nExpr==1 );
+    sqlite3ExprListSetSortOrder(pList, sortOrder, SQLITE_SO_UNDEFINED);
+  }else{
+    sqlite3ExprListCheckLength(pParse, pList, "index");
+    if( pParse->nErr ) goto exit_create_index;
+  }
+
+  /* Figure out how many bytes of space are required to store explicitly
+  ** specified collation sequence names.
+  */
+  for(i=0; i<pList->nExpr; i++){
+    Expr *pExpr = pList->a[i].pExpr;
+    assert( pExpr!=0 );
+    if( pExpr->op==TK_COLLATE ){
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      nExtra += (1 + sqlite3Strlen30(pExpr->u.zToken));
+    }
+  }
+
+  /*
+  ** Allocate the index structure.
+  */
+  nName = sqlite3Strlen30(zName);
+  nExtraCol = pPk ? pPk->nKeyCol : 1;
+  assert( pList->nExpr + nExtraCol <= 32767 /* Fits in i16 */ );
+  pIndex = sqlite3AllocateIndexObject(db, pList->nExpr + nExtraCol,
+                                      nName + nExtra + 1, &zExtra);
+  if( db->mallocFailed ){
+    goto exit_create_index;
+  }
+  assert( EIGHT_BYTE_ALIGNMENT(pIndex->aiRowLogEst) );
+  assert( EIGHT_BYTE_ALIGNMENT(pIndex->azColl) );
+  pIndex->zName = zExtra;
+  zExtra += nName + 1;
+  memcpy(pIndex->zName, zName, nName+1);
+  pIndex->pTable = pTab;
+  pIndex->onError = (u8)onError;
+  pIndex->uniqNotNull = onError!=OE_None;
+  pIndex->idxType = idxType;
+  pIndex->pSchema = db->aDb[iDb].pSchema;
+  pIndex->nKeyCol = pList->nExpr;
+  if( pPIWhere ){
+    sqlite3ResolveSelfReference(pParse, pTab, NC_PartIdx, pPIWhere, 0);
+    pIndex->pPartIdxWhere = pPIWhere;
+    pPIWhere = 0;
+  }
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+
+  /* Check to see if we should honor DESC requests on index columns
+  */
+  if( pDb->pSchema->file_format>=4 ){
+    sortOrderMask = -1;   /* Honor DESC */
+  }else{
+    sortOrderMask = 0;    /* Ignore DESC */
+  }
+
+  /* Analyze the list of expressions that form the terms of the index and
+  ** report any errors.  In the common case where the expression is exactly
+  ** a table column, store that column in aiColumn[].  For general expressions,
+  ** populate pIndex->aColExpr and store XN_EXPR (-2) in aiColumn[].
+  **
+  ** TODO: Issue a warning if two or more columns of the index are identical.
+  ** TODO: Issue a warning if the table primary key is used as part of the
+  ** index key.
+  */
+  pListItem = pList->a;
+  if( IN_RENAME_OBJECT ){
+    pIndex->aColExpr = pList;
+    pList = 0;
+  }
+  for(i=0; i<pIndex->nKeyCol; i++, pListItem++){
+    Expr *pCExpr;                  /* The i-th index expression */
+    int requestedSortOrder;        /* ASC or DESC on the i-th expression */
+    const char *zColl;             /* Collation sequence name */
+
+    sqlite3StringToId(pListItem->pExpr);
+    sqlite3ResolveSelfReference(pParse, pTab, NC_IdxExpr, pListItem->pExpr, 0);
+    if( pParse->nErr ) goto exit_create_index;
+    pCExpr = sqlite3ExprSkipCollate(pListItem->pExpr);
+    if( pCExpr->op!=TK_COLUMN ){
+      if( pTab==pParse->pNewTable ){
+        sqlite3ErrorMsg(pParse, "expressions prohibited in PRIMARY KEY and "
+                                "UNIQUE constraints");
+        goto exit_create_index;
+      }
+      if( pIndex->aColExpr==0 ){
+        pIndex->aColExpr = pList;
+        pList = 0;
+      }
+      j = XN_EXPR;
+      pIndex->aiColumn[i] = XN_EXPR;
+      pIndex->uniqNotNull = 0;
+      pIndex->bHasExpr = 1;
+    }else{
+      j = pCExpr->iColumn;
+      assert( j<=0x7fff );
+      if( j<0 ){
+        j = pTab->iPKey;
+        pIndex->bIdxRowid = 1;
+      }else{
+        if( pTab->aCol[j].notNull==0 ){
+          pIndex->uniqNotNull = 0;
+        }
+        if( pTab->aCol[j].colFlags & COLFLAG_VIRTUAL ){
+          pIndex->bHasVCol = 1;
+          pIndex->bHasExpr = 1;
+        }
+      }
+      pIndex->aiColumn[i] = (i16)j;
+    }
+    zColl = 0;
+    if( pListItem->pExpr->op==TK_COLLATE ){
+      int nColl;
+      assert( !ExprHasProperty(pListItem->pExpr, EP_IntValue) );
+      zColl = pListItem->pExpr->u.zToken;
+      nColl = sqlite3Strlen30(zColl) + 1;
+      assert( nExtra>=nColl );
+      memcpy(zExtra, zColl, nColl);
+      zColl = zExtra;
+      zExtra += nColl;
+      nExtra -= nColl;
+    }else if( j>=0 ){
+      zColl = sqlite3ColumnColl(&pTab->aCol[j]);
+    }
+    if( !zColl ) zColl = sqlite3StrBINARY;
+    if( !db->init.busy && !sqlite3LocateCollSeq(pParse, zColl) ){
+      goto exit_create_index;
+    }
+    pIndex->azColl[i] = zColl;
+    requestedSortOrder = pListItem->fg.sortFlags & sortOrderMask;
+    pIndex->aSortOrder[i] = (u8)requestedSortOrder;
+  }
+
+  /* Append the table key to the end of the index.  For WITHOUT ROWID
+  ** tables (when pPk!=0) this will be the declared PRIMARY KEY.  For
+  ** normal tables (when pPk==0) this will be the rowid.
+  */
+  if( pPk ){
+    for(j=0; j<pPk->nKeyCol; j++){
+      int x = pPk->aiColumn[j];
+      assert( x>=0 );
+      if( isDupColumn(pIndex, pIndex->nKeyCol, pPk, j) ){
+        pIndex->nColumn--;
+      }else{
+        testcase( hasColumn(pIndex->aiColumn,pIndex->nKeyCol,x) );
+        pIndex->aiColumn[i] = x;
+        pIndex->azColl[i] = pPk->azColl[j];
+        pIndex->aSortOrder[i] = pPk->aSortOrder[j];
+        i++;
+      }
+    }
+    assert( i==pIndex->nColumn );
+  }else{
+    pIndex->aiColumn[i] = XN_ROWID;
+    pIndex->azColl[i] = sqlite3StrBINARY;
+  }
+  sqlite3DefaultRowEst(pIndex);
+  if( pParse->pNewTable==0 ) estimateIndexWidth(pIndex);
+
+  /* If this index contains every column of its table, then mark
+  ** it as a covering index */
+  assert( HasRowid(pTab)
+      || pTab->iPKey<0 || sqlite3TableColumnToIndex(pIndex, pTab->iPKey)>=0 );
+  recomputeColumnsNotIndexed(pIndex);
+  if( pTblName!=0 && pIndex->nColumn>=pTab->nCol ){
+    pIndex->isCovering = 1;
+    for(j=0; j<pTab->nCol; j++){
+      if( j==pTab->iPKey ) continue;
+      if( sqlite3TableColumnToIndex(pIndex,j)>=0 ) continue;
+      pIndex->isCovering = 0;
+      break;
+    }
+  }
+
+  if( pTab==pParse->pNewTable ){
+    /* This routine has been called to create an automatic index as a
+    ** result of a PRIMARY KEY or UNIQUE clause on a column definition, or
+    ** a PRIMARY KEY or UNIQUE clause following the column definitions.
+    ** i.e. one of:
+    **
+    ** CREATE TABLE t(x PRIMARY KEY, y);
+    ** CREATE TABLE t(x, y, UNIQUE(x, y));
+    **
+    ** Either way, check to see if the table already has such an index. If
+    ** so, don't bother creating this one. This only applies to
+    ** automatically created indices. Users can do as they wish with
+    ** explicit indices.
+    **
+    ** Two UNIQUE or PRIMARY KEY constraints are considered equivalent
+    ** (and thus suppressing the second one) even if they have different
+    ** sort orders.
+    **
+    ** If there are different collating sequences or if the columns of
+    ** the constraint occur in different orders, then the constraints are
+    ** considered distinct and both result in separate indices.
+    */
+    Index *pIdx;
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      int k;
+      assert( IsUniqueIndex(pIdx) );
+      assert( pIdx->idxType!=SQLITE_IDXTYPE_APPDEF );
+      assert( IsUniqueIndex(pIndex) );
+
+      if( pIdx->nKeyCol!=pIndex->nKeyCol ) continue;
+      for(k=0; k<pIdx->nKeyCol; k++){
+        const char *z1;
+        const char *z2;
+        assert( pIdx->aiColumn[k]>=0 );
+        if( pIdx->aiColumn[k]!=pIndex->aiColumn[k] ) break;
+        z1 = pIdx->azColl[k];
+        z2 = pIndex->azColl[k];
+        if( sqlite3StrICmp(z1, z2) ) break;
+      }
+      if( k==pIdx->nKeyCol ){
+        if( pIdx->onError!=pIndex->onError ){
+          /* This constraint creates the same index as a previous
+          ** constraint specified somewhere in the CREATE TABLE statement.
+          ** However the ON CONFLICT clauses are different. If both this
+          ** constraint and the previous equivalent constraint have explicit
+          ** ON CONFLICT clauses this is an error. Otherwise, use the
+          ** explicitly specified behavior for the index.
+          */
+          if( !(pIdx->onError==OE_Default || pIndex->onError==OE_Default) ){
+            sqlite3ErrorMsg(pParse,
+                "conflicting ON CONFLICT clauses specified", 0);
+          }
+          if( pIdx->onError==OE_Default ){
+            pIdx->onError = pIndex->onError;
+          }
+        }
+        if( idxType==SQLITE_IDXTYPE_PRIMARYKEY ) pIdx->idxType = idxType;
+        if( IN_RENAME_OBJECT ){
+          pIndex->pNext = pParse->pNewIndex;
+          pParse->pNewIndex = pIndex;
+          pIndex = 0;
+        }
+        goto exit_create_index;
+      }
+    }
+  }
+
+  if( !IN_RENAME_OBJECT ){
+
+    /* Link the new Index structure to its table and to the other
+    ** in-memory database structures.
+    */
+    assert( pParse->nErr==0 );
+    if( db->init.busy ){
+      Index *p;
+      assert( !IN_SPECIAL_PARSE );
+      assert( sqlite3SchemaMutexHeld(db, 0, pIndex->pSchema) );
+      if( pTblName!=0 ){
+        pIndex->tnum = db->init.newTnum;
+        if( sqlite3IndexHasDuplicateRootPage(pIndex) ){
+          sqlite3ErrorMsg(pParse, "invalid rootpage");
+          pParse->rc = SQLITE_CORRUPT_BKPT;
+          goto exit_create_index;
+        }
+      }
+      p = sqlite3HashInsert(&pIndex->pSchema->idxHash,
+          pIndex->zName, pIndex);
+      if( p ){
+        assert( p==pIndex );  /* Malloc must have failed */
+        sqlite3OomFault(db);
+        goto exit_create_index;
+      }
+      db->mDbFlags |= DBFLAG_SchemaChange;
+    }
+
+    /* If this is the initial CREATE INDEX statement (or CREATE TABLE if the
+    ** index is an implied index for a UNIQUE or PRIMARY KEY constraint) then
+    ** emit code to allocate the index rootpage on disk and make an entry for
+    ** the index in the sqlite_schema table and populate the index with
+    ** content.  But, do not do this if we are simply reading the sqlite_schema
+    ** table to parse the schema, or if this index is the PRIMARY KEY index
+    ** of a WITHOUT ROWID table.
+    **
+    ** If pTblName==0 it means this index is generated as an implied PRIMARY KEY
+    ** or UNIQUE index in a CREATE TABLE statement.  Since the table
+    ** has just been created, it contains no data and the index initialization
+    ** step can be skipped.
+    */
+    else if( HasRowid(pTab) || pTblName!=0 ){
+      Vdbe *v;
+      char *zStmt;
+      int iMem = ++pParse->nMem;
+
+      v = sqlite3GetVdbe(pParse);
+      if( v==0 ) goto exit_create_index;
+
+      sqlite3BeginWriteOperation(pParse, 1, iDb);
+
+      /* Create the rootpage for the index using CreateIndex. But before
+      ** doing so, code a Noop instruction and store its address in
+      ** Index.tnum. This is required in case this index is actually a
+      ** PRIMARY KEY and the table is actually a WITHOUT ROWID table. In
+      ** that case the convertToWithoutRowidTable() routine will replace
+      ** the Noop with a Goto to jump over the VDBE code generated below. */
+      pIndex->tnum = (Pgno)sqlite3VdbeAddOp0(v, OP_Noop);
+      sqlite3VdbeAddOp3(v, OP_CreateBtree, iDb, iMem, BTREE_BLOBKEY);
+
+      /* Gather the complete text of the CREATE INDEX statement into
+      ** the zStmt variable
+      */
+      assert( pName!=0 || pStart==0 );
+      if( pStart ){
+        int n = (int)(pParse->sLastToken.z - pName->z) + pParse->sLastToken.n;
+        if( pName->z[n-1]==';' ) n--;
+        /* A named index with an explicit CREATE INDEX statement */
+        zStmt = sqlite3MPrintf(db, "CREATE%s INDEX %.*s",
+            onError==OE_None ? "" : " UNIQUE", n, pName->z);
+      }else{
+        /* An automatic index created by a PRIMARY KEY or UNIQUE constraint */
+        /* zStmt = sqlite3MPrintf(""); */
+        zStmt = 0;
+      }
+
+      /* Add an entry in sqlite_schema for this index
+      */
+      sqlite3NestedParse(pParse,
+         "INSERT INTO %Q." LEGACY_SCHEMA_TABLE " VALUES('index',%Q,%Q,#%d,%Q);",
+         db->aDb[iDb].zDbSName,
+         pIndex->zName,
+         pTab->zName,
+         iMem,
+         zStmt
+      );
+      sqlite3DbFree(db, zStmt);
+
+      /* Fill the index with data and reparse the schema. Code an OP_Expire
+      ** to invalidate all pre-compiled statements.
+      */
+      if( pTblName ){
+        sqlite3RefillIndex(pParse, pIndex, iMem);
+        sqlite3ChangeCookie(pParse, iDb);
+        sqlite3VdbeAddParseSchemaOp(v, iDb,
+            sqlite3MPrintf(db, "name='%q' AND type='index'", pIndex->zName), 0);
+        sqlite3VdbeAddOp2(v, OP_Expire, 0, 1);
+      }
+
+      sqlite3VdbeJumpHere(v, (int)pIndex->tnum);
+    }
+  }
+  if( db->init.busy || pTblName==0 ){
+    pIndex->pNext = pTab->pIndex;
+    pTab->pIndex = pIndex;
+    pIndex = 0;
+  }
+  else if( IN_RENAME_OBJECT ){
+    assert( pParse->pNewIndex==0 );
+    pParse->pNewIndex = pIndex;
+    pIndex = 0;
+  }
+
+  /* Clean up before exiting */
+exit_create_index:
+  if( pIndex ) sqlite3FreeIndex(db, pIndex);
+  if( pTab ){
+    /* Ensure all REPLACE indexes on pTab are at the end of the pIndex list.
+    ** The list was already ordered when this routine was entered, so at this
+    ** point at most a single index (the newly added index) will be out of
+    ** order.  So we have to reorder at most one index. */
+    Index **ppFrom;
+    Index *pThis;
+    for(ppFrom=&pTab->pIndex; (pThis = *ppFrom)!=0; ppFrom=&pThis->pNext){
+      Index *pNext;
+      if( pThis->onError!=OE_Replace ) continue;
+      while( (pNext = pThis->pNext)!=0 && pNext->onError!=OE_Replace ){
+        *ppFrom = pNext;
+        pThis->pNext = pNext->pNext;
+        pNext->pNext = pThis;
+        ppFrom = &pNext->pNext;
+      }
+      break;
+    }
+#ifdef SQLITE_DEBUG
+    /* Verify that all REPLACE indexes really are now at the end
+    ** of the index list.  In other words, no other index type ever
+    ** comes after a REPLACE index on the list. */
+    for(pThis = pTab->pIndex; pThis; pThis=pThis->pNext){
+      assert( pThis->onError!=OE_Replace
+           || pThis->pNext==0
+           || pThis->pNext->onError==OE_Replace );
+    }
+#endif
+  }
+  sqlite3ExprDelete(db, pPIWhere);
+  sqlite3ExprListDelete(db, pList);
+  sqlite3SrcListDelete(db, pTblName);
+  sqlite3DbFree(db, zName);
+}
+
+/*
+** Fill the Index.aiRowEst[] array with default information - information
+** to be used when we have not run the ANALYZE command.
+**
+** aiRowEst[0] is supposed to contain the number of elements in the index.
+** Since we do not know, guess 1 million.  aiRowEst[1] is an estimate of the
+** number of rows in the table that match any particular value of the
+** first column of the index.  aiRowEst[2] is an estimate of the number
+** of rows that match any particular combination of the first 2 columns
+** of the index.  And so forth.  It must always be the case that
+*
+**           aiRowEst[N]<=aiRowEst[N-1]
+**           aiRowEst[N]>=1
+**
+** Apart from that, we have little to go on besides intuition as to
+** how aiRowEst[] should be initialized.  The numbers generated here
+** are based on typical values found in actual indices.
+*/
+SQLITE_PRIVATE void sqlite3DefaultRowEst(Index *pIdx){
+               /*                10,  9,  8,  7,  6 */
+  static const LogEst aVal[] = { 33, 32, 30, 28, 26 };
+  LogEst *a = pIdx->aiRowLogEst;
+  LogEst x;
+  int nCopy = MIN(ArraySize(aVal), pIdx->nKeyCol);
+  int i;
+
+  /* Indexes with default row estimates should not have stat1 data */
+  assert( !pIdx->hasStat1 );
+
+  /* Set the first entry (number of rows in the index) to the estimated
+  ** number of rows in the table, or half the number of rows in the table
+  ** for a partial index.
+  **
+  ** 2020-05-27:  If some of the stat data is coming from the sqlite_stat1
+  ** table but other parts we are having to guess at, then do not let the
+  ** estimated number of rows in the table be less than 1000 (LogEst 99).
+  ** Failure to do this can cause the indexes for which we do not have
+  ** stat1 data to be ignored by the query planner.
+  */
+  x = pIdx->pTable->nRowLogEst;
+  assert( 99==sqlite3LogEst(1000) );
+  if( x<99 ){
+    pIdx->pTable->nRowLogEst = x = 99;
+  }
+  if( pIdx->pPartIdxWhere!=0 ){ x -= 10;  assert( 10==sqlite3LogEst(2) ); }
+  a[0] = x;
+
+  /* Estimate that a[1] is 10, a[2] is 9, a[3] is 8, a[4] is 7, a[5] is
+  ** 6 and each subsequent value (if any) is 5.  */
+  memcpy(&a[1], aVal, nCopy*sizeof(LogEst));
+  for(i=nCopy+1; i<=pIdx->nKeyCol; i++){
+    a[i] = 23;                    assert( 23==sqlite3LogEst(5) );
+  }
+
+  assert( 0==sqlite3LogEst(1) );
+  if( IsUniqueIndex(pIdx) ) a[pIdx->nKeyCol] = 0;
+}
+
+/*
+** This routine will drop an existing named index.  This routine
+** implements the DROP INDEX statement.
+*/
+SQLITE_PRIVATE void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
+  Index *pIndex;
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  if( db->mallocFailed ){
+    goto exit_drop_index;
+  }
+  assert( pParse->nErr==0 );   /* Never called with prior non-OOM errors */
+  assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 );
+  assert( pName->a[0].fg.isSubquery==0 );
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    goto exit_drop_index;
+  }
+  pIndex = sqlite3FindIndex(db, pName->a[0].zName, pName->a[0].u4.zDatabase);
+  if( pIndex==0 ){
+    if( !ifExists ){
+      sqlite3ErrorMsg(pParse, "no such index: %S", pName->a);
+    }else{
+      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].u4.zDatabase);
+      sqlite3ForceNotReadOnly(pParse);
+    }
+    pParse->checkSchema = 1;
+    goto exit_drop_index;
+  }
+  if( pIndex->idxType!=SQLITE_IDXTYPE_APPDEF ){
+    sqlite3ErrorMsg(pParse, "index associated with UNIQUE "
+      "or PRIMARY KEY constraint cannot be dropped", 0);
+    goto exit_drop_index;
+  }
+  iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  {
+    int code = SQLITE_DROP_INDEX;
+    Table *pTab = pIndex->pTable;
+    const char *zDb = db->aDb[iDb].zDbSName;
+    const char *zTab = SCHEMA_TABLE(iDb);
+    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
+      goto exit_drop_index;
+    }
+    if( !OMIT_TEMPDB && iDb==1 ) code = SQLITE_DROP_TEMP_INDEX;
+    if( sqlite3AuthCheck(pParse, code, pIndex->zName, pTab->zName, zDb) ){
+      goto exit_drop_index;
+    }
+  }
+#endif
+
+  /* Generate code to remove the index and from the schema table */
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3BeginWriteOperation(pParse, 1, iDb);
+    sqlite3NestedParse(pParse,
+       "DELETE FROM %Q." LEGACY_SCHEMA_TABLE " WHERE name=%Q AND type='index'",
+       db->aDb[iDb].zDbSName, pIndex->zName
+    );
+    sqlite3ClearStatTables(pParse, iDb, "idx", pIndex->zName);
+    sqlite3ChangeCookie(pParse, iDb);
+    destroyRootPage(pParse, pIndex->tnum, iDb);
+    sqlite3VdbeAddOp4(v, OP_DropIndex, iDb, 0, 0, pIndex->zName, 0);
+  }
+
+exit_drop_index:
+  sqlite3SrcListDelete(db, pName);
+}
+
+/*
+** pArray is a pointer to an array of objects. Each object in the
+** array is szEntry bytes in size. This routine uses sqlite3DbRealloc()
+** to extend the array so that there is space for a new object at the end.
+**
+** When this function is called, *pnEntry contains the current size of
+** the array (in entries - so the allocation is ((*pnEntry) * szEntry) bytes
+** in total).
+**
+** If the realloc() is successful (i.e. if no OOM condition occurs), the
+** space allocated for the new object is zeroed, *pnEntry updated to
+** reflect the new size of the array and a pointer to the new allocation
+** returned. *pIdx is set to the index of the new array entry in this case.
+**
+** Otherwise, if the realloc() fails, *pIdx is set to -1, *pnEntry remains
+** unchanged and a copy of pArray returned.
+*/
+SQLITE_PRIVATE void *sqlite3ArrayAllocate(
+  sqlite3 *db,      /* Connection to notify of malloc failures */
+  void *pArray,     /* Array of objects.  Might be reallocated */
+  int szEntry,      /* Size of each object in the array */
+  int *pnEntry,     /* Number of objects currently in use */
+  int *pIdx         /* Write the index of a new slot here */
+){
+  char *z;
+  sqlite3_int64 n = *pIdx = *pnEntry;
+  if( (n & (n-1))==0 ){
+    sqlite3_int64 sz = (n==0) ? 1 : 2*n;
+    void *pNew = sqlite3DbRealloc(db, pArray, sz*szEntry);
+    if( pNew==0 ){
+      *pIdx = -1;
+      return pArray;
+    }
+    pArray = pNew;
+  }
+  z = (char*)pArray;
+  memset(&z[n * szEntry], 0, szEntry);
+  ++*pnEntry;
+  return pArray;
+}
+
+/*
+** Append a new element to the given IdList.  Create a new IdList if
+** need be.
+**
+** A new IdList is returned, or NULL if malloc() fails.
+*/
+SQLITE_PRIVATE IdList *sqlite3IdListAppend(Parse *pParse, IdList *pList, Token *pToken){
+  sqlite3 *db = pParse->db;
+  int i;
+  if( pList==0 ){
+    pList = sqlite3DbMallocZero(db, sizeof(IdList) );
+    if( pList==0 ) return 0;
+  }else{
+    IdList *pNew;
+    pNew = sqlite3DbRealloc(db, pList,
+                 sizeof(IdList) + pList->nId*sizeof(pList->a));
+    if( pNew==0 ){
+      sqlite3IdListDelete(db, pList);
+      return 0;
+    }
+    pList = pNew;
+  }
+  i = pList->nId++;
+  pList->a[i].zName = sqlite3NameFromToken(db, pToken);
+  if( IN_RENAME_OBJECT && pList->a[i].zName ){
+    sqlite3RenameTokenMap(pParse, (void*)pList->a[i].zName, pToken);
+  }
+  return pList;
+}
+
+/*
+** Delete an IdList.
+*/
+SQLITE_PRIVATE void sqlite3IdListDelete(sqlite3 *db, IdList *pList){
+  int i;
+  assert( db!=0 );
+  if( pList==0 ) return;
+  for(i=0; i<pList->nId; i++){
+    sqlite3DbFree(db, pList->a[i].zName);
+  }
+  sqlite3DbNNFreeNN(db, pList);
+}
+
+/*
+** Return the index in pList of the identifier named zId.  Return -1
+** if not found.
+*/
+SQLITE_PRIVATE int sqlite3IdListIndex(IdList *pList, const char *zName){
+  int i;
+  assert( pList!=0 );
+  for(i=0; i<pList->nId; i++){
+    if( sqlite3StrICmp(pList->a[i].zName, zName)==0 ) return i;
+  }
+  return -1;
+}
+
+/*
+** Maximum size of a SrcList object.
+** The SrcList object is used to represent the FROM clause of a
+** SELECT statement, and the query planner cannot deal with more
+** than 64 tables in a join.  So any value larger than 64 here
+** is sufficient for most uses.  Smaller values, like say 10, are
+** appropriate for small and memory-limited applications.
+*/
+#ifndef SQLITE_MAX_SRCLIST
+# define SQLITE_MAX_SRCLIST 200
+#endif
+
+/*
+** Expand the space allocated for the given SrcList object by
+** creating nExtra new slots beginning at iStart.  iStart is zero based.
+** New slots are zeroed.
+**
+** For example, suppose a SrcList initially contains two entries: A,B.
+** To append 3 new entries onto the end, do this:
+**
+**    sqlite3SrcListEnlarge(db, pSrclist, 3, 2);
+**
+** After the call above it would contain:  A, B, nil, nil, nil.
+** If the iStart argument had been 1 instead of 2, then the result
+** would have been:  A, nil, nil, nil, B.  To prepend the new slots,
+** the iStart value would be 0.  The result then would
+** be: nil, nil, nil, A, B.
+**
+** If a memory allocation fails or the SrcList becomes too large, leave
+** the original SrcList unchanged, return NULL, and leave an error message
+** in pParse.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListEnlarge(
+  Parse *pParse,     /* Parsing context into which errors are reported */
+  SrcList *pSrc,     /* The SrcList to be enlarged */
+  int nExtra,        /* Number of new slots to add to pSrc->a[] */
+  int iStart         /* Index in pSrc->a[] of first new slot */
+){
+  int i;
+
+  /* Sanity checking on calling parameters */
+  assert( iStart>=0 );
+  assert( nExtra>=1 );
+  assert( pSrc!=0 );
+  assert( iStart<=pSrc->nSrc );
+
+  /* Allocate additional space if needed */
+  if( (u32)pSrc->nSrc+nExtra>pSrc->nAlloc ){
+    SrcList *pNew;
+    sqlite3_int64 nAlloc = 2*(sqlite3_int64)pSrc->nSrc+nExtra;
+    sqlite3 *db = pParse->db;
+
+    if( pSrc->nSrc+nExtra>=SQLITE_MAX_SRCLIST ){
+      sqlite3ErrorMsg(pParse, "too many FROM clause terms, max: %d",
+                      SQLITE_MAX_SRCLIST);
+      return 0;
+    }
+    if( nAlloc>SQLITE_MAX_SRCLIST ) nAlloc = SQLITE_MAX_SRCLIST;
+    pNew = sqlite3DbRealloc(db, pSrc,
+               sizeof(*pSrc) + (nAlloc-1)*sizeof(pSrc->a[0]) );
+    if( pNew==0 ){
+      assert( db->mallocFailed );
+      return 0;
+    }
+    pSrc = pNew;
+    pSrc->nAlloc = nAlloc;
+  }
+
+  /* Move existing slots that come after the newly inserted slots
+  ** out of the way */
+  for(i=pSrc->nSrc-1; i>=iStart; i--){
+    pSrc->a[i+nExtra] = pSrc->a[i];
+  }
+  pSrc->nSrc += nExtra;
+
+  /* Zero the newly allocated slots */
+  memset(&pSrc->a[iStart], 0, sizeof(pSrc->a[0])*nExtra);
+  for(i=iStart; i<iStart+nExtra; i++){
+    pSrc->a[i].iCursor = -1;
+  }
+
+  /* Return a pointer to the enlarged SrcList */
+  return pSrc;
+}
+
+
+/*
+** Append a new table name to the given SrcList.  Create a new SrcList if
+** need be.  A new entry is created in the SrcList even if pTable is NULL.
+**
+** A SrcList is returned, or NULL if there is an OOM error or if the
+** SrcList grows to large.  The returned
+** SrcList might be the same as the SrcList that was input or it might be
+** a new one.  If an OOM error does occurs, then the prior value of pList
+** that is input to this routine is automatically freed.
+**
+** If pDatabase is not null, it means that the table has an optional
+** database name prefix.  Like this:  "database.table".  The pDatabase
+** points to the table name and the pTable points to the database name.
+** The SrcList.a[].zName field is filled with the table name which might
+** come from pTable (if pDatabase is NULL) or from pDatabase.
+** SrcList.a[].zDatabase is filled with the database name from pTable,
+** or with NULL if no database is specified.
+**
+** In other words, if call like this:
+**
+**         sqlite3SrcListAppend(D,A,B,0);
+**
+** Then B is a table name and the database name is unspecified.  If called
+** like this:
+**
+**         sqlite3SrcListAppend(D,A,B,C);
+**
+** Then C is the table name and B is the database name.  If C is defined
+** then so is B.  In other words, we never have a case where:
+**
+**         sqlite3SrcListAppend(D,A,0,C);
+**
+** Both pTable and pDatabase are assumed to be quoted.  They are dequoted
+** before being added to the SrcList.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppend(
+  Parse *pParse,      /* Parsing context, in which errors are reported */
+  SrcList *pList,     /* Append to this SrcList. NULL creates a new SrcList */
+  Token *pTable,      /* Table to append */
+  Token *pDatabase    /* Database of the table */
+){
+  SrcItem *pItem;
+  sqlite3 *db;
+  assert( pDatabase==0 || pTable!=0 );  /* Cannot have C without B */
+  assert( pParse!=0 );
+  assert( pParse->db!=0 );
+  db = pParse->db;
+  if( pList==0 ){
+    pList = sqlite3DbMallocRawNN(pParse->db, sizeof(SrcList) );
+    if( pList==0 ) return 0;
+    pList->nAlloc = 1;
+    pList->nSrc = 1;
+    memset(&pList->a[0], 0, sizeof(pList->a[0]));
+    pList->a[0].iCursor = -1;
+  }else{
+    SrcList *pNew = sqlite3SrcListEnlarge(pParse, pList, 1, pList->nSrc);
+    if( pNew==0 ){
+      sqlite3SrcListDelete(db, pList);
+      return 0;
+    }else{
+      pList = pNew;
+    }
+  }
+  pItem = &pList->a[pList->nSrc-1];
+  if( pDatabase && pDatabase->z==0 ){
+    pDatabase = 0;
+  }
+  assert( pItem->fg.fixedSchema==0 );
+  assert( pItem->fg.isSubquery==0 );
+  if( pDatabase ){
+    pItem->zName = sqlite3NameFromToken(db, pDatabase);
+    pItem->u4.zDatabase = sqlite3NameFromToken(db, pTable);
+  }else{
+    pItem->zName = sqlite3NameFromToken(db, pTable);
+    pItem->u4.zDatabase = 0;
+  }
+  return pList;
+}
+
+/*
+** Assign VdbeCursor index numbers to all tables in a SrcList
+*/
+SQLITE_PRIVATE void sqlite3SrcListAssignCursors(Parse *pParse, SrcList *pList){
+  int i;
+  SrcItem *pItem;
+  assert( pList || pParse->db->mallocFailed );
+  if( ALWAYS(pList) ){
+    for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
+      if( pItem->iCursor>=0 ) continue;
+      pItem->iCursor = pParse->nTab++;
+      if( pItem->fg.isSubquery ){
+        assert( pItem->u4.pSubq!=0 );
+        assert( pItem->u4.pSubq->pSelect!=0 );
+        assert( pItem->u4.pSubq->pSelect->pSrc!=0 );
+        sqlite3SrcListAssignCursors(pParse, pItem->u4.pSubq->pSelect->pSrc);
+      }
+    }
+  }
+}
+
+/*
+** Delete a Subquery object and its substructure.
+*/
+SQLITE_PRIVATE void sqlite3SubqueryDelete(sqlite3 *db, Subquery *pSubq){
+  assert( pSubq!=0 && pSubq->pSelect!=0 );
+  sqlite3SelectDelete(db, pSubq->pSelect);
+  sqlite3DbFree(db, pSubq);
+}
+
+/*
+** Remove a Subquery from a SrcItem.  Return the associated Select object.
+** The returned Select becomes the responsibility of the caller.
+*/
+SQLITE_PRIVATE Select *sqlite3SubqueryDetach(sqlite3 *db, SrcItem *pItem){
+  Select *pSel;
+  assert( pItem!=0 );
+  assert( pItem->fg.isSubquery );
+  pSel = pItem->u4.pSubq->pSelect;
+  sqlite3DbFree(db, pItem->u4.pSubq);
+  pItem->u4.pSubq = 0;
+  pItem->fg.isSubquery = 0;
+  return pSel;
+}
+
+/*
+** Delete an entire SrcList including all its substructure.
+*/
+SQLITE_PRIVATE void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
+  int i;
+  SrcItem *pItem;
+  assert( db!=0 );
+  if( pList==0 ) return;
+  for(pItem=pList->a, i=0; i<pList->nSrc; i++, pItem++){
+
+    /* Check invariants on SrcItem */
+    assert( !pItem->fg.isIndexedBy || !pItem->fg.isTabFunc );
+    assert( !pItem->fg.isCte || !pItem->fg.isIndexedBy );
+    assert( !pItem->fg.fixedSchema || !pItem->fg.isSubquery );
+    assert( !pItem->fg.isSubquery || (pItem->u4.pSubq!=0 &&
+                                      pItem->u4.pSubq->pSelect!=0) );
+
+    if( pItem->zName ) sqlite3DbNNFreeNN(db, pItem->zName);
+    if( pItem->zAlias ) sqlite3DbNNFreeNN(db, pItem->zAlias);
+    if( pItem->fg.isSubquery ){
+      sqlite3SubqueryDelete(db, pItem->u4.pSubq);
+    }else if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+      sqlite3DbNNFreeNN(db, pItem->u4.zDatabase);
+    }
+    if( pItem->fg.isIndexedBy ) sqlite3DbFree(db, pItem->u1.zIndexedBy);
+    if( pItem->fg.isTabFunc ) sqlite3ExprListDelete(db, pItem->u1.pFuncArg);
+    sqlite3DeleteTable(db, pItem->pSTab);
+    if( pItem->fg.isUsing ){
+      sqlite3IdListDelete(db, pItem->u3.pUsing);
+    }else if( pItem->u3.pOn ){
+      sqlite3ExprDelete(db, pItem->u3.pOn);
+    }
+  }
+  sqlite3DbNNFreeNN(db, pList);
+}
+
+/*
+** Attach a Subquery object to pItem->uv.pSubq.  Set the
+** pSelect value but leave all the other values initialized
+** to zero.
+**
+** A copy of the Select object is made if dupSelect is true, and the
+** SrcItem takes responsibility for deleting the copy.  If dupSelect is
+** false, ownership of the Select passes to the SrcItem.  Either way,
+** the SrcItem will take responsibility for deleting the Select.
+**
+** When dupSelect is zero, that means the Select might get deleted right
+** away if there is an OOM error.  Beware.
+**
+** Return non-zero on success.  Return zero on an OOM error.
+*/
+SQLITE_PRIVATE int sqlite3SrcItemAttachSubquery(
+  Parse *pParse,     /* Parsing context */
+  SrcItem *pItem,    /* Item to which the subquery is to be attached */
+  Select *pSelect,   /* The subquery SELECT.  Must be non-NULL */
+  int dupSelect      /* If true, attach a copy of pSelect, not pSelect itself.*/
+){
+  Subquery *p;
+  assert( pSelect!=0 );
+  assert( pItem->fg.isSubquery==0 );
+  if( pItem->fg.fixedSchema ){
+    pItem->u4.pSchema = 0;
+    pItem->fg.fixedSchema = 0;
+  }else if( pItem->u4.zDatabase!=0 ){
+    sqlite3DbFree(pParse->db, pItem->u4.zDatabase);
+    pItem->u4.zDatabase = 0;
+  }
+  if( dupSelect ){
+    pSelect = sqlite3SelectDup(pParse->db, pSelect, 0);
+    if( pSelect==0 ) return 0;
+  }
+  p = pItem->u4.pSubq = sqlite3DbMallocRawNN(pParse->db, sizeof(Subquery));
+  if( p==0 ){
+    sqlite3SelectDelete(pParse->db, pSelect);
+    return 0;
+  }
+  pItem->fg.isSubquery = 1;
+  p->pSelect = pSelect;
+  assert( offsetof(Subquery, pSelect)==0 );
+  memset(((char*)p)+sizeof(p->pSelect), 0, sizeof(*p)-sizeof(p->pSelect));
+  return 1;
+}
+
+
+/*
+** This routine is called by the parser to add a new term to the
+** end of a growing FROM clause.  The "p" parameter is the part of
+** the FROM clause that has already been constructed.  "p" is NULL
+** if this is the first term of the FROM clause.  pTable and pDatabase
+** are the name of the table and database named in the FROM clause term.
+** pDatabase is NULL if the database name qualifier is missing - the
+** usual case.  If the term has an alias, then pAlias points to the
+** alias token.  If the term is a subquery, then pSubquery is the
+** SELECT statement that the subquery encodes.  The pTable and
+** pDatabase parameters are NULL for subqueries.  The pOn and pUsing
+** parameters are the content of the ON and USING clauses.
+**
+** Return a new SrcList which encodes is the FROM with the new
+** term added.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendFromTerm(
+  Parse *pParse,          /* Parsing context */
+  SrcList *p,             /* The left part of the FROM clause already seen */
+  Token *pTable,          /* Name of the table to add to the FROM clause */
+  Token *pDatabase,       /* Name of the database containing pTable */
+  Token *pAlias,          /* The right-hand side of the AS subexpression */
+  Select *pSubquery,      /* A subquery used in place of a table name */
+  OnOrUsing *pOnUsing     /* Either the ON clause or the USING clause */
+){
+  SrcItem *pItem;
+  sqlite3 *db = pParse->db;
+  if( !p && pOnUsing!=0 && (pOnUsing->pOn || pOnUsing->pUsing) ){
+    sqlite3ErrorMsg(pParse, "a JOIN clause is required before %s",
+      (pOnUsing->pOn ? "ON" : "USING")
+    );
+    goto append_from_error;
+  }
+  p = sqlite3SrcListAppend(pParse, p, pTable, pDatabase);
+  if( p==0 ){
+    goto append_from_error;
+  }
+  assert( p->nSrc>0 );
+  pItem = &p->a[p->nSrc-1];
+  assert( (pTable==0)==(pDatabase==0) );
+  assert( pItem->zName==0 || pDatabase!=0 );
+  if( IN_RENAME_OBJECT && pItem->zName ){
+    Token *pToken = (ALWAYS(pDatabase) && pDatabase->z) ? pDatabase : pTable;
+    sqlite3RenameTokenMap(pParse, pItem->zName, pToken);
+  }
+  assert( pAlias!=0 );
+  if( pAlias->n ){
+    pItem->zAlias = sqlite3NameFromToken(db, pAlias);
+  }
+  assert( pSubquery==0 || pDatabase==0 );
+  if( pSubquery ){
+    if( sqlite3SrcItemAttachSubquery(pParse, pItem, pSubquery, 0) ){
+      if( pSubquery->selFlags & SF_NestedFrom ){
+        pItem->fg.isNestedFrom = 1;
+      }
+    }
+  }
+  assert( pOnUsing==0 || pOnUsing->pOn==0 || pOnUsing->pUsing==0 );
+  assert( pItem->fg.isUsing==0 );
+  if( pOnUsing==0 ){
+    pItem->u3.pOn = 0;
+  }else if( pOnUsing->pUsing ){
+    pItem->fg.isUsing = 1;
+    pItem->u3.pUsing = pOnUsing->pUsing;
+  }else{
+    pItem->u3.pOn = pOnUsing->pOn;
+  }
+  return p;
+
+append_from_error:
+  assert( p==0 );
+  sqlite3ClearOnOrUsing(db, pOnUsing);
+  sqlite3SelectDelete(db, pSubquery);
+  return 0;
+}
+
+/*
+** Add an INDEXED BY or NOT INDEXED clause to the most recently added
+** element of the source-list passed as the second argument.
+*/
+SQLITE_PRIVATE void sqlite3SrcListIndexedBy(Parse *pParse, SrcList *p, Token *pIndexedBy){
+  assert( pIndexedBy!=0 );
+  if( p && pIndexedBy->n>0 ){
+    SrcItem *pItem;
+    assert( p->nSrc>0 );
+    pItem = &p->a[p->nSrc-1];
+    assert( pItem->fg.notIndexed==0 );
+    assert( pItem->fg.isIndexedBy==0 );
+    assert( pItem->fg.isTabFunc==0 );
+    if( pIndexedBy->n==1 && !pIndexedBy->z ){
+      /* A "NOT INDEXED" clause was supplied. See parse.y
+      ** construct "indexed_opt" for details. */
+      pItem->fg.notIndexed = 1;
+    }else{
+      pItem->u1.zIndexedBy = sqlite3NameFromToken(pParse->db, pIndexedBy);
+      pItem->fg.isIndexedBy = 1;
+      assert( pItem->fg.isCte==0 );  /* No collision on union u2 */
+    }
+  }
+}
+
+/*
+** Append the contents of SrcList p2 to SrcList p1 and return the resulting
+** SrcList. Or, if an error occurs, return NULL. In all cases, p1 and p2
+** are deleted by this function.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendList(Parse *pParse, SrcList *p1, SrcList *p2){
+  assert( p1 && p1->nSrc==1 );
+  if( p2 ){
+    SrcList *pNew = sqlite3SrcListEnlarge(pParse, p1, p2->nSrc, 1);
+    if( pNew==0 ){
+      sqlite3SrcListDelete(pParse->db, p2);
+    }else{
+      p1 = pNew;
+      memcpy(&p1->a[1], p2->a, p2->nSrc*sizeof(SrcItem));
+      sqlite3DbFree(pParse->db, p2);
+      p1->a[0].fg.jointype |= (JT_LTORJ & p1->a[1].fg.jointype);
+    }
+  }
+  return p1;
+}
+
+/*
+** Add the list of function arguments to the SrcList entry for a
+** table-valued-function.
+*/
+SQLITE_PRIVATE void sqlite3SrcListFuncArgs(Parse *pParse, SrcList *p, ExprList *pList){
+  if( p ){
+    SrcItem *pItem = &p->a[p->nSrc-1];
+    assert( pItem->fg.notIndexed==0 );
+    assert( pItem->fg.isIndexedBy==0 );
+    assert( pItem->fg.isTabFunc==0 );
+    pItem->u1.pFuncArg = pList;
+    pItem->fg.isTabFunc = 1;
+  }else{
+    sqlite3ExprListDelete(pParse->db, pList);
+  }
+}
+
+/*
+** When building up a FROM clause in the parser, the join operator
+** is initially attached to the left operand.  But the code generator
+** expects the join operator to be on the right operand.  This routine
+** Shifts all join operators from left to right for an entire FROM
+** clause.
+**
+** Example: Suppose the join is like this:
+**
+**           A natural cross join B
+**
+** The operator is "natural cross join".  The A and B operands are stored
+** in p->a[0] and p->a[1], respectively.  The parser initially stores the
+** operator with A.  This routine shifts that operator over to B.
+**
+** Additional changes:
+**
+**   *   All tables to the left of the right-most RIGHT JOIN are tagged with
+**       JT_LTORJ (mnemonic: Left Table Of Right Join) so that the
+**       code generator can easily tell that the table is part of
+**       the left operand of at least one RIGHT JOIN.
+*/
+SQLITE_PRIVATE void sqlite3SrcListShiftJoinType(Parse *pParse, SrcList *p){
+  (void)pParse;
+  if( p && p->nSrc>1 ){
+    int i = p->nSrc-1;
+    u8 allFlags = 0;
+    do{
+      allFlags |= p->a[i].fg.jointype = p->a[i-1].fg.jointype;
+    }while( (--i)>0 );
+    p->a[0].fg.jointype = 0;
+
+    /* All terms to the left of a RIGHT JOIN should be tagged with the
+    ** JT_LTORJ flags */
+    if( allFlags & JT_RIGHT ){
+      for(i=p->nSrc-1; ALWAYS(i>0) && (p->a[i].fg.jointype&JT_RIGHT)==0; i--){}
+      i--;
+      assert( i>=0 );
+      do{
+        p->a[i].fg.jointype |= JT_LTORJ;
+      }while( (--i)>=0 );
+    }
+  }
+}
+
+/*
+** Generate VDBE code for a BEGIN statement.
+*/
+SQLITE_PRIVATE void sqlite3BeginTransaction(Parse *pParse, int type){
+  sqlite3 *db;
+  Vdbe *v;
+  int i;
+
+  assert( pParse!=0 );
+  db = pParse->db;
+  assert( db!=0 );
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "BEGIN", 0, 0) ){
+    return;
+  }
+  v = sqlite3GetVdbe(pParse);
+  if( !v ) return;
+  if( type!=TK_DEFERRED ){
+    for(i=0; i<db->nDb; i++){
+      int eTxnType;
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt && sqlite3BtreeIsReadonly(pBt) ){
+        eTxnType = 0;  /* Read txn */
+      }else if( type==TK_EXCLUSIVE ){
+        eTxnType = 2;  /* Exclusive txn */
+      }else{
+        eTxnType = 1;  /* Write txn */
+      }
+      sqlite3VdbeAddOp2(v, OP_Transaction, i, eTxnType);
+      sqlite3VdbeUsesBtree(v, i);
+    }
+  }
+  sqlite3VdbeAddOp0(v, OP_AutoCommit);
+}
+
+/*
+** Generate VDBE code for a COMMIT or ROLLBACK statement.
+** Code for ROLLBACK is generated if eType==TK_ROLLBACK.  Otherwise
+** code is generated for a COMMIT.
+*/
+SQLITE_PRIVATE void sqlite3EndTransaction(Parse *pParse, int eType){
+  Vdbe *v;
+  int isRollback;
+
+  assert( pParse!=0 );
+  assert( pParse->db!=0 );
+  assert( eType==TK_COMMIT || eType==TK_END || eType==TK_ROLLBACK );
+  isRollback = eType==TK_ROLLBACK;
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION,
+       isRollback ? "ROLLBACK" : "COMMIT", 0, 0) ){
+    return;
+  }
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp2(v, OP_AutoCommit, 1, isRollback);
+  }
+}
+
+/*
+** This function is called by the parser when it parses a command to create,
+** release or rollback an SQL savepoint.
+*/
+SQLITE_PRIVATE void sqlite3Savepoint(Parse *pParse, int op, Token *pName){
+  char *zName = sqlite3NameFromToken(pParse->db, pName);
+  if( zName ){
+    Vdbe *v = sqlite3GetVdbe(pParse);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    static const char * const az[] = { "BEGIN", "RELEASE", "ROLLBACK" };
+    assert( !SAVEPOINT_BEGIN && SAVEPOINT_RELEASE==1 && SAVEPOINT_ROLLBACK==2 );
+#endif
+    if( !v || sqlite3AuthCheck(pParse, SQLITE_SAVEPOINT, az[op], zName, 0) ){
+      sqlite3DbFree(pParse->db, zName);
+      return;
+    }
+    sqlite3VdbeAddOp4(v, OP_Savepoint, op, 0, 0, zName, P4_DYNAMIC);
+  }
+}
+
+/*
+** Make sure the TEMP database is open and available for use.  Return
+** the number of errors.  Leave any error messages in the pParse structure.
+*/
+SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  if( db->aDb[1].pBt==0 && !pParse->explain ){
+    int rc;
+    Btree *pBt;
+    static const int flags =
+          SQLITE_OPEN_READWRITE |
+          SQLITE_OPEN_CREATE |
+          SQLITE_OPEN_EXCLUSIVE |
+          SQLITE_OPEN_DELETEONCLOSE |
+          SQLITE_OPEN_TEMP_DB;
+
+    rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pBt, 0, flags);
+    if( rc!=SQLITE_OK ){
+      sqlite3ErrorMsg(pParse, "unable to open a temporary database "
+        "file for storing temporary tables");
+      pParse->rc = rc;
+      return 1;
+    }
+    db->aDb[1].pBt = pBt;
+    assert( db->aDb[1].pSchema );
+    if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize, 0, 0) ){
+      sqlite3OomFault(db);
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Record the fact that the schema cookie will need to be verified
+** for database iDb.  The code to actually verify the schema cookie
+** will occur at the end of the top-level VDBE and will be generated
+** later, by sqlite3FinishCoding().
+*/
+static void sqlite3CodeVerifySchemaAtToplevel(Parse *pToplevel, int iDb){
+  assert( iDb>=0 && iDb<pToplevel->db->nDb );
+  assert( pToplevel->db->aDb[iDb].pBt!=0 || iDb==1 );
+  assert( iDb<SQLITE_MAX_DB );
+  assert( sqlite3SchemaMutexHeld(pToplevel->db, iDb, 0) );
+  if( DbMaskTest(pToplevel->cookieMask, iDb)==0 ){
+    DbMaskSet(pToplevel->cookieMask, iDb);
+    if( !OMIT_TEMPDB && iDb==1 ){
+      sqlite3OpenTempDatabase(pToplevel);
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
+  sqlite3CodeVerifySchemaAtToplevel(sqlite3ParseToplevel(pParse), iDb);
+}
+
+
+/*
+** If argument zDb is NULL, then call sqlite3CodeVerifySchema() for each
+** attached database. Otherwise, invoke it for the database named zDb only.
+*/
+SQLITE_PRIVATE void sqlite3CodeVerifyNamedSchema(Parse *pParse, const char *zDb){
+  sqlite3 *db = pParse->db;
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Db *pDb = &db->aDb[i];
+    if( pDb->pBt && (!zDb || 0==sqlite3StrICmp(zDb, pDb->zDbSName)) ){
+      sqlite3CodeVerifySchema(pParse, i);
+    }
+  }
+}
+
+/*
+** Generate VDBE code that prepares for doing an operation that
+** might change the database.
+**
+** This routine starts a new transaction if we are not already within
+** a transaction.  If we are already within a transaction, then a checkpoint
+** is set if the setStatement parameter is true.  A checkpoint should
+** be set for operations that might fail (due to a constraint) part of
+** the way through and which will need to undo some writes without having to
+** rollback the whole transaction.  For operations where all constraints
+** can be checked before any changes are made to the database, it is never
+** necessary to undo a write and the checkpoint should not be set.
+*/
+SQLITE_PRIVATE void sqlite3BeginWriteOperation(Parse *pParse, int setStatement, int iDb){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  sqlite3CodeVerifySchemaAtToplevel(pToplevel, iDb);
+  DbMaskSet(pToplevel->writeMask, iDb);
+  pToplevel->isMultiWrite |= setStatement;
+}
+
+/*
+** Indicate that the statement currently under construction might write
+** more than one entry (example: deleting one row then inserting another,
+** inserting multiple rows in a table, or inserting a row and index entries.)
+** If an abort occurs after some of these writes have completed, then it will
+** be necessary to undo the completed writes.
+*/
+SQLITE_PRIVATE void sqlite3MultiWrite(Parse *pParse){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  pToplevel->isMultiWrite = 1;
+}
+
+/*
+** The code generator calls this routine if is discovers that it is
+** possible to abort a statement prior to completion.  In order to
+** perform this abort without corrupting the database, we need to make
+** sure that the statement is protected by a statement transaction.
+**
+** Technically, we only need to set the mayAbort flag if the
+** isMultiWrite flag was previously set.  There is a time dependency
+** such that the abort must occur after the multiwrite.  This makes
+** some statements involving the REPLACE conflict resolution algorithm
+** go a little faster.  But taking advantage of this time dependency
+** makes it more difficult to prove that the code is correct (in
+** particular, it prevents us from writing an effective
+** implementation of sqlite3AssertMayAbort()) and so we have chosen
+** to take the safe route and skip the optimization.
+*/
+SQLITE_PRIVATE void sqlite3MayAbort(Parse *pParse){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  pToplevel->mayAbort = 1;
+}
+
+/*
+** Code an OP_Halt that causes the vdbe to return an SQLITE_CONSTRAINT
+** error. The onError parameter determines which (if any) of the statement
+** and/or current transaction is rolled back.
+*/
+SQLITE_PRIVATE void sqlite3HaltConstraint(
+  Parse *pParse,    /* Parsing context */
+  int errCode,      /* extended error code */
+  int onError,      /* Constraint type */
+  char *p4,         /* Error message */
+  i8 p4type,        /* P4_STATIC or P4_TRANSIENT */
+  u8 p5Errmsg       /* P5_ErrMsg type */
+){
+  Vdbe *v;
+  assert( pParse->pVdbe!=0 );
+  v = sqlite3GetVdbe(pParse);
+  assert( (errCode&0xff)==SQLITE_CONSTRAINT || pParse->nested );
+  if( onError==OE_Abort ){
+    sqlite3MayAbort(pParse);
+  }
+  sqlite3VdbeAddOp4(v, OP_Halt, errCode, onError, 0, p4, p4type);
+  sqlite3VdbeChangeP5(v, p5Errmsg);
+}
+
+/*
+** Code an OP_Halt due to UNIQUE or PRIMARY KEY constraint violation.
+*/
+SQLITE_PRIVATE void sqlite3UniqueConstraint(
+  Parse *pParse,    /* Parsing context */
+  int onError,      /* Constraint type */
+  Index *pIdx       /* The index that triggers the constraint */
+){
+  char *zErr;
+  int j;
+  StrAccum errMsg;
+  Table *pTab = pIdx->pTable;
+
+  sqlite3StrAccumInit(&errMsg, pParse->db, 0, 0,
+                      pParse->db->aLimit[SQLITE_LIMIT_LENGTH]);
+  if( pIdx->aColExpr ){
+    sqlite3_str_appendf(&errMsg, "index '%q'", pIdx->zName);
+  }else{
+    for(j=0; j<pIdx->nKeyCol; j++){
+      char *zCol;
+      assert( pIdx->aiColumn[j]>=0 );
+      zCol = pTab->aCol[pIdx->aiColumn[j]].zCnName;
+      if( j ) sqlite3_str_append(&errMsg, ", ", 2);
+      sqlite3_str_appendall(&errMsg, pTab->zName);
+      sqlite3_str_append(&errMsg, ".", 1);
+      sqlite3_str_appendall(&errMsg, zCol);
+    }
+  }
+  zErr = sqlite3StrAccumFinish(&errMsg);
+  sqlite3HaltConstraint(pParse,
+    IsPrimaryKeyIndex(pIdx) ? SQLITE_CONSTRAINT_PRIMARYKEY
+                            : SQLITE_CONSTRAINT_UNIQUE,
+    onError, zErr, P4_DYNAMIC, P5_ConstraintUnique);
+}
+
+
+/*
+** Code an OP_Halt due to non-unique rowid.
+*/
+SQLITE_PRIVATE void sqlite3RowidConstraint(
+  Parse *pParse,    /* Parsing context */
+  int onError,      /* Conflict resolution algorithm */
+  Table *pTab       /* The table with the non-unique rowid */
+){
+  char *zMsg;
+  int rc;
+  if( pTab->iPKey>=0 ){
+    zMsg = sqlite3MPrintf(pParse->db, "%s.%s", pTab->zName,
+                          pTab->aCol[pTab->iPKey].zCnName);
+    rc = SQLITE_CONSTRAINT_PRIMARYKEY;
+  }else{
+    zMsg = sqlite3MPrintf(pParse->db, "%s.rowid", pTab->zName);
+    rc = SQLITE_CONSTRAINT_ROWID;
+  }
+  sqlite3HaltConstraint(pParse, rc, onError, zMsg, P4_DYNAMIC,
+                        P5_ConstraintUnique);
+}
+
+/*
+** Check to see if pIndex uses the collating sequence pColl.  Return
+** true if it does and false if it does not.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+static int collationMatch(const char *zColl, Index *pIndex){
+  int i;
+  assert( zColl!=0 );
+  for(i=0; i<pIndex->nColumn; i++){
+    const char *z = pIndex->azColl[i];
+    assert( z!=0 || pIndex->aiColumn[i]<0 );
+    if( pIndex->aiColumn[i]>=0 && 0==sqlite3StrICmp(z, zColl) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+#endif
+
+/*
+** Recompute all indices of pTab that use the collating sequence pColl.
+** If pColl==0 then recompute all indices of pTab.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+static void reindexTable(Parse *pParse, Table *pTab, char const *zColl){
+  if( !IsVirtual(pTab) ){
+    Index *pIndex;              /* An index associated with pTab */
+
+    for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
+      if( zColl==0 || collationMatch(zColl, pIndex) ){
+        int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+        sqlite3BeginWriteOperation(pParse, 0, iDb);
+        sqlite3RefillIndex(pParse, pIndex, -1);
+      }
+    }
+  }
+}
+#endif
+
+/*
+** Recompute all indices of all tables in all databases where the
+** indices use the collating sequence pColl.  If pColl==0 then recompute
+** all indices everywhere.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+static void reindexDatabases(Parse *pParse, char const *zColl){
+  Db *pDb;                    /* A single database */
+  int iDb;                    /* The database index number */
+  sqlite3 *db = pParse->db;   /* The database connection */
+  HashElem *k;                /* For looping over tables in pDb */
+  Table *pTab;                /* A table in the database */
+
+  assert( sqlite3BtreeHoldsAllMutexes(db) );  /* Needed for schema access */
+  for(iDb=0, pDb=db->aDb; iDb<db->nDb; iDb++, pDb++){
+    assert( pDb!=0 );
+    for(k=sqliteHashFirst(&pDb->pSchema->tblHash);  k; k=sqliteHashNext(k)){
+      pTab = (Table*)sqliteHashData(k);
+      reindexTable(pParse, pTab, zColl);
+    }
+  }
+}
+#endif
+
+/*
+** Generate code for the REINDEX command.
+**
+**        REINDEX                            -- 1
+**        REINDEX  <collation>               -- 2
+**        REINDEX  ?<database>.?<tablename>  -- 3
+**        REINDEX  ?<database>.?<indexname>  -- 4
+**
+** Form 1 causes all indices in all attached databases to be rebuilt.
+** Form 2 rebuilds all indices in all databases that use the named
+** collating function.  Forms 3 and 4 rebuild the named index or all
+** indices associated with the named table.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+SQLITE_PRIVATE void sqlite3Reindex(Parse *pParse, Token *pName1, Token *pName2){
+  CollSeq *pColl;             /* Collating sequence to be reindexed, or NULL */
+  char *z;                    /* Name of a table or index */
+  const char *zDb;            /* Name of the database */
+  Table *pTab;                /* A table in the database */
+  Index *pIndex;              /* An index associated with pTab */
+  int iDb;                    /* The database index number */
+  sqlite3 *db = pParse->db;   /* The database connection */
+  Token *pObjName;            /* Name of the table or index to be reindexed */
+
+  /* Read the database schema. If an error occurs, leave an error message
+  ** and code in pParse and return NULL. */
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    return;
+  }
+
+  if( pName1==0 ){
+    reindexDatabases(pParse, 0);
+    return;
+  }else if( NEVER(pName2==0) || pName2->z==0 ){
+    char *zColl;
+    assert( pName1->z );
+    zColl = sqlite3NameFromToken(pParse->db, pName1);
+    if( !zColl ) return;
+    pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);
+    if( pColl ){
+      reindexDatabases(pParse, zColl);
+      sqlite3DbFree(db, zColl);
+      return;
+    }
+    sqlite3DbFree(db, zColl);
+  }
+  iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pObjName);
+  if( iDb<0 ) return;
+  z = sqlite3NameFromToken(db, pObjName);
+  if( z==0 ) return;
+  zDb = pName2->n ? db->aDb[iDb].zDbSName : 0;
+  pTab = sqlite3FindTable(db, z, zDb);
+  if( pTab ){
+    reindexTable(pParse, pTab, 0);
+    sqlite3DbFree(db, z);
+    return;
+  }
+  pIndex = sqlite3FindIndex(db, z, zDb);
+  sqlite3DbFree(db, z);
+  if( pIndex ){
+    iDb = sqlite3SchemaToIndex(db, pIndex->pTable->pSchema);
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    sqlite3RefillIndex(pParse, pIndex, -1);
+    return;
+  }
+  sqlite3ErrorMsg(pParse, "unable to identify the object to be reindexed");
+}
+#endif
+
+/*
+** Return a KeyInfo structure that is appropriate for the given Index.
+**
+** The caller should invoke sqlite3KeyInfoUnref() on the returned object
+** when it has finished using it.
+*/
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoOfIndex(Parse *pParse, Index *pIdx){
+  int i;
+  int nCol = pIdx->nColumn;
+  int nKey = pIdx->nKeyCol;
+  KeyInfo *pKey;
+  if( pParse->nErr ) return 0;
+  if( pIdx->uniqNotNull ){
+    pKey = sqlite3KeyInfoAlloc(pParse->db, nKey, nCol-nKey);
+  }else{
+    pKey = sqlite3KeyInfoAlloc(pParse->db, nCol, 0);
+  }
+  if( pKey ){
+    assert( sqlite3KeyInfoIsWriteable(pKey) );
+    for(i=0; i<nCol; i++){
+      const char *zColl = pIdx->azColl[i];
+      pKey->aColl[i] = zColl==sqlite3StrBINARY ? 0 :
+                        sqlite3LocateCollSeq(pParse, zColl);
+      pKey->aSortFlags[i] = pIdx->aSortOrder[i];
+      assert( 0==(pKey->aSortFlags[i] & KEYINFO_ORDER_BIGNULL) );
+    }
+    if( pParse->nErr ){
+      assert( pParse->rc==SQLITE_ERROR_MISSING_COLLSEQ );
+      if( pIdx->bNoQuery==0 ){
+        /* Deactivate the index because it contains an unknown collating
+        ** sequence.  The only way to reactive the index is to reload the
+        ** schema.  Adding the missing collating sequence later does not
+        ** reactive the index.  The application had the chance to register
+        ** the missing index using the collation-needed callback.  For
+        ** simplicity, SQLite will not give the application a second chance.
+        */
+        pIdx->bNoQuery = 1;
+        pParse->rc = SQLITE_ERROR_RETRY;
+      }
+      sqlite3KeyInfoUnref(pKey);
+      pKey = 0;
+    }
+  }
+  return pKey;
+}
+
+#ifndef SQLITE_OMIT_CTE
+/*
+** Create a new CTE object
+*/
+SQLITE_PRIVATE Cte *sqlite3CteNew(
+  Parse *pParse,          /* Parsing context */
+  Token *pName,           /* Name of the common-table */
+  ExprList *pArglist,     /* Optional column name list for the table */
+  Select *pQuery,         /* Query used to initialize the table */
+  u8 eM10d                /* The MATERIALIZED flag */
+){
+  Cte *pNew;
+  sqlite3 *db = pParse->db;
+
+  pNew = sqlite3DbMallocZero(db, sizeof(*pNew));
+  assert( pNew!=0 || db->mallocFailed );
+
+  if( db->mallocFailed ){
+    sqlite3ExprListDelete(db, pArglist);
+    sqlite3SelectDelete(db, pQuery);
+  }else{
+    pNew->pSelect = pQuery;
+    pNew->pCols = pArglist;
+    pNew->zName = sqlite3NameFromToken(pParse->db, pName);
+    pNew->eM10d = eM10d;
+  }
+  return pNew;
+}
+
+/*
+** Clear information from a Cte object, but do not deallocate storage
+** for the object itself.
+*/
+static void cteClear(sqlite3 *db, Cte *pCte){
+  assert( pCte!=0 );
+  sqlite3ExprListDelete(db, pCte->pCols);
+  sqlite3SelectDelete(db, pCte->pSelect);
+  sqlite3DbFree(db, pCte->zName);
+}
+
+/*
+** Free the contents of the CTE object passed as the second argument.
+*/
+SQLITE_PRIVATE void sqlite3CteDelete(sqlite3 *db, Cte *pCte){
+  assert( pCte!=0 );
+  cteClear(db, pCte);
+  sqlite3DbFree(db, pCte);
+}
+
+/*
+** This routine is invoked once per CTE by the parser while parsing a
+** WITH clause.  The CTE described by the third argument is added to
+** the WITH clause of the second argument.  If the second argument is
+** NULL, then a new WITH argument is created.
+*/
+SQLITE_PRIVATE With *sqlite3WithAdd(
+  Parse *pParse,          /* Parsing context */
+  With *pWith,            /* Existing WITH clause, or NULL */
+  Cte *pCte               /* CTE to add to the WITH clause */
+){
+  sqlite3 *db = pParse->db;
+  With *pNew;
+  char *zName;
+
+  if( pCte==0 ){
+    return pWith;
+  }
+
+  /* Check that the CTE name is unique within this WITH clause. If
+  ** not, store an error in the Parse structure. */
+  zName = pCte->zName;
+  if( zName && pWith ){
+    int i;
+    for(i=0; i<pWith->nCte; i++){
+      if( sqlite3StrICmp(zName, pWith->a[i].zName)==0 ){
+        sqlite3ErrorMsg(pParse, "duplicate WITH table name: %s", zName);
+      }
+    }
+  }
+
+  if( pWith ){
+    sqlite3_int64 nByte = sizeof(*pWith) + (sizeof(pWith->a[1]) * pWith->nCte);
+    pNew = sqlite3DbRealloc(db, pWith, nByte);
+  }else{
+    pNew = sqlite3DbMallocZero(db, sizeof(*pWith));
+  }
+  assert( (pNew!=0 && zName!=0) || db->mallocFailed );
+
+  if( db->mallocFailed ){
+    sqlite3CteDelete(db, pCte);
+    pNew = pWith;
+  }else{
+    pNew->a[pNew->nCte++] = *pCte;
+    sqlite3DbFree(db, pCte);
+  }
+
+  return pNew;
+}
+
+/*
+** Free the contents of the With object passed as the second argument.
+*/
+SQLITE_PRIVATE void sqlite3WithDelete(sqlite3 *db, With *pWith){
+  if( pWith ){
+    int i;
+    for(i=0; i<pWith->nCte; i++){
+      cteClear(db, &pWith->a[i]);
+    }
+    sqlite3DbFree(db, pWith);
+  }
+}
+SQLITE_PRIVATE void sqlite3WithDeleteGeneric(sqlite3 *db, void *pWith){
+  sqlite3WithDelete(db, (With*)pWith);
+}
+#endif /* !defined(SQLITE_OMIT_CTE) */
+
+/************** End of build.c ***********************************************/
+/************** Begin file callback.c ****************************************/
+/*
+** 2005 May 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains functions used to access the internal hash tables
+** of user defined functions and collation sequences.
+*/
+
+/* #include "sqliteInt.h" */
+
+/*
+** Invoke the 'collation needed' callback to request a collation sequence
+** in the encoding enc of name zName, length nName.
+*/
+static void callCollNeeded(sqlite3 *db, int enc, const char *zName){
+  assert( !db->xCollNeeded || !db->xCollNeeded16 );
+  if( db->xCollNeeded ){
+    char *zExternal = sqlite3DbStrDup(db, zName);
+    if( !zExternal ) return;
+    db->xCollNeeded(db->pCollNeededArg, db, enc, zExternal);
+    sqlite3DbFree(db, zExternal);
+  }
+#ifndef SQLITE_OMIT_UTF16
+  if( db->xCollNeeded16 ){
+    char const *zExternal;
+    sqlite3_value *pTmp = sqlite3ValueNew(db);
+    sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF8, SQLITE_STATIC);
+    zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE);
+    if( zExternal ){
+      db->xCollNeeded16(db->pCollNeededArg, db, (int)ENC(db), zExternal);
+    }
+    sqlite3ValueFree(pTmp);
+  }
+#endif
+}
+
+/*
+** This routine is called if the collation factory fails to deliver a
+** collation function in the best encoding but there may be other versions
+** of this collation function (for other text encodings) available. Use one
+** of these instead if they exist. Avoid a UTF-8 <-> UTF-16 conversion if
+** possible.
+*/
+static int synthCollSeq(sqlite3 *db, CollSeq *pColl){
+  CollSeq *pColl2;
+  char *z = pColl->zName;
+  int i;
+  static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 };
+  for(i=0; i<3; i++){
+    pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, 0);
+    if( pColl2->xCmp!=0 ){
+      memcpy(pColl, pColl2, sizeof(CollSeq));
+      pColl->xDel = 0;         /* Do not copy the destructor */
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_ERROR;
+}
+
+/*
+** This routine is called on a collation sequence before it is used to
+** check that it is defined. An undefined collation sequence exists when
+** a database is loaded that contains references to collation sequences
+** that have not been defined by sqlite3_create_collation() etc.
+**
+** If required, this routine calls the 'collation needed' callback to
+** request a definition of the collating sequence. If this doesn't work,
+** an equivalent collating sequence that uses a text encoding different
+** from the main database is substituted, if one is available.
+*/
+SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){
+  if( pColl && pColl->xCmp==0 ){
+    const char *zName = pColl->zName;
+    sqlite3 *db = pParse->db;
+    CollSeq *p = sqlite3GetCollSeq(pParse, ENC(db), pColl, zName);
+    if( !p ){
+      return SQLITE_ERROR;
+    }
+    assert( p==pColl );
+  }
+  return SQLITE_OK;
+}
+
+
+
+/*
+** Locate and return an entry from the db.aCollSeq hash table. If the entry
+** specified by zName and nName is not found and parameter 'create' is
+** true, then create a new entry. Otherwise return NULL.
+**
+** Each pointer stored in the sqlite3.aCollSeq hash table contains an
+** array of three CollSeq structures. The first is the collation sequence
+** preferred for UTF-8, the second UTF-16le, and the third UTF-16be.
+**
+** Stored immediately after the three collation sequences is a copy of
+** the collation sequence name. A pointer to this string is stored in
+** each collation sequence structure.
+*/
+static CollSeq *findCollSeqEntry(
+  sqlite3 *db,          /* Database connection */
+  const char *zName,    /* Name of the collating sequence */
+  int create            /* Create a new entry if true */
+){
+  CollSeq *pColl;
+  pColl = sqlite3HashFind(&db->aCollSeq, zName);
+
+  if( 0==pColl && create ){
+    int nName = sqlite3Strlen30(zName) + 1;
+    pColl = sqlite3DbMallocZero(db, 3*sizeof(*pColl) + nName);
+    if( pColl ){
+      CollSeq *pDel = 0;
+      pColl[0].zName = (char*)&pColl[3];
+      pColl[0].enc = SQLITE_UTF8;
+      pColl[1].zName = (char*)&pColl[3];
+      pColl[1].enc = SQLITE_UTF16LE;
+      pColl[2].zName = (char*)&pColl[3];
+      pColl[2].enc = SQLITE_UTF16BE;
+      memcpy(pColl[0].zName, zName, nName);
+      pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, pColl);
+
+      /* If a malloc() failure occurred in sqlite3HashInsert(), it will
+      ** return the pColl pointer to be deleted (because it wasn't added
+      ** to the hash table).
+      */
+      assert( pDel==0 || pDel==pColl );
+      if( pDel!=0 ){
+        sqlite3OomFault(db);
+        sqlite3DbFree(db, pDel);
+        pColl = 0;
+      }
+    }
+  }
+  return pColl;
+}
+
+/*
+** Parameter zName points to a UTF-8 encoded string nName bytes long.
+** Return the CollSeq* pointer for the collation sequence named zName
+** for the encoding 'enc' from the database 'db'.
+**
+** If the entry specified is not found and 'create' is true, then create a
+** new entry.  Otherwise return NULL.
+**
+** A separate function sqlite3LocateCollSeq() is a wrapper around
+** this routine.  sqlite3LocateCollSeq() invokes the collation factory
+** if necessary and generates an error message if the collating sequence
+** cannot be found.
+**
+** See also: sqlite3LocateCollSeq(), sqlite3GetCollSeq()
+*/
+SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(
+  sqlite3 *db,          /* Database connection to search */
+  u8 enc,               /* Desired text encoding */
+  const char *zName,    /* Name of the collating sequence.  Might be NULL */
+  int create            /* True to create CollSeq if doesn't already exist */
+){
+  CollSeq *pColl;
+  assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
+  assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
+  if( zName ){
+    pColl = findCollSeqEntry(db, zName, create);
+    if( pColl ) pColl += enc-1;
+  }else{
+    pColl = db->pDfltColl;
+  }
+  return pColl;
+}
+
+/*
+** Change the text encoding for a database connection. This means that
+** the pDfltColl must change as well.
+*/
+SQLITE_PRIVATE void sqlite3SetTextEncoding(sqlite3 *db, u8 enc){
+  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
+  db->enc = enc;
+  /* EVIDENCE-OF: R-08308-17224 The default collating function for all
+  ** strings is BINARY.
+  */
+  db->pDfltColl = sqlite3FindCollSeq(db, enc, sqlite3StrBINARY, 0);
+  sqlite3ExpirePreparedStatements(db, 1);
+}
+
+/*
+** This function is responsible for invoking the collation factory callback
+** or substituting a collation sequence of a different encoding when the
+** requested collation sequence is not available in the desired encoding.
+**
+** If it is not NULL, then pColl must point to the database native encoding
+** collation sequence with name zName, length nName.
+**
+** The return value is either the collation sequence to be used in database
+** db for collation type name zName, length nName, or NULL, if no collation
+** sequence can be found.  If no collation is found, leave an error message.
+**
+** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq()
+*/
+SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(
+  Parse *pParse,        /* Parsing context */
+  u8 enc,               /* The desired encoding for the collating sequence */
+  CollSeq *pColl,       /* Collating sequence with native encoding, or NULL */
+  const char *zName     /* Collating sequence name */
+){
+  CollSeq *p;
+  sqlite3 *db = pParse->db;
+
+  p = pColl;
+  if( !p ){
+    p = sqlite3FindCollSeq(db, enc, zName, 0);
+  }
+  if( !p || !p->xCmp ){
+    /* No collation sequence of this type for this encoding is registered.
+    ** Call the collation factory to see if it can supply us with one.
+    */
+    callCollNeeded(db, enc, zName);
+    p = sqlite3FindCollSeq(db, enc, zName, 0);
+  }
+  if( p && !p->xCmp && synthCollSeq(db, p) ){
+    p = 0;
+  }
+  assert( !p || p->xCmp );
+  if( p==0 ){
+    sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
+    pParse->rc = SQLITE_ERROR_MISSING_COLLSEQ;
+  }
+  return p;
+}
+
+/*
+** This function returns the collation sequence for database native text
+** encoding identified by the string zName.
+**
+** If the requested collation sequence is not available, or not available
+** in the database native encoding, the collation factory is invoked to
+** request it. If the collation factory does not supply such a sequence,
+** and the sequence is available in another text encoding, then that is
+** returned instead.
+**
+** If no versions of the requested collations sequence are available, or
+** another error occurs, NULL is returned and an error message written into
+** pParse.
+**
+** This routine is a wrapper around sqlite3FindCollSeq().  This routine
+** invokes the collation factory if the named collation cannot be found
+** and generates an error message.
+**
+** See also: sqlite3FindCollSeq(), sqlite3GetCollSeq()
+*/
+SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName){
+  sqlite3 *db = pParse->db;
+  u8 enc = ENC(db);
+  u8 initbusy = db->init.busy;
+  CollSeq *pColl;
+
+  pColl = sqlite3FindCollSeq(db, enc, zName, initbusy);
+  if( !initbusy && (!pColl || !pColl->xCmp) ){
+    pColl = sqlite3GetCollSeq(pParse, enc, pColl, zName);
+  }
+
+  return pColl;
+}
+
+/* During the search for the best function definition, this procedure
+** is called to test how well the function passed as the first argument
+** matches the request for a function with nArg arguments in a system
+** that uses encoding enc. The value returned indicates how well the
+** request is matched. A higher value indicates a better match.
+**
+** If nArg is -1 that means to only return a match (non-zero) if p->nArg
+** is also -1.  In other words, we are searching for a function that
+** takes a variable number of arguments.
+**
+** If nArg is -2 that means that we are searching for any function
+** regardless of the number of arguments it uses, so return a positive
+** match score for any
+**
+** The returned value is always between 0 and 6, as follows:
+**
+** 0: Not a match.
+** 1: UTF8/16 conversion required and function takes any number of arguments.
+** 2: UTF16 byte order change required and function takes any number of args.
+** 3: encoding matches and function takes any number of arguments
+** 4: UTF8/16 conversion required - argument count matches exactly
+** 5: UTF16 byte order conversion required - argument count matches exactly
+** 6: Perfect match:  encoding and argument count match exactly.
+**
+** If nArg==(-2) then any function with a non-null xSFunc is
+** a perfect match and any function with xSFunc NULL is
+** a non-match.
+*/
+#define FUNC_PERFECT_MATCH 6  /* The score for a perfect match */
+static int matchQuality(
+  FuncDef *p,     /* The function we are evaluating for match quality */
+  int nArg,       /* Desired number of arguments.  (-1)==any */
+  u8 enc          /* Desired text encoding */
+){
+  int match;
+  assert( p->nArg>=(-4) && p->nArg!=(-2) );
+  assert( nArg>=(-2) );
+
+  /* Wrong number of arguments means "no match" */
+  if( p->nArg!=nArg ){
+    if( nArg==(-2) ) return p->xSFunc==0 ? 0 : FUNC_PERFECT_MATCH;
+    if( p->nArg>=0 ) return 0;
+    /* Special p->nArg values available to built-in functions only:
+    **    -3     1 or more arguments required
+    **    -4     2 or more arguments required
+    */
+    if( p->nArg<(-2) && nArg<(-2-p->nArg) ) return 0;
+  }
+
+  /* Give a better score to a function with a specific number of arguments
+  ** than to function that accepts any number of arguments. */
+  if( p->nArg==nArg ){
+    match = 4;
+  }else{
+    match = 1;
+  }
+
+  /* Bonus points if the text encoding matches */
+  if( enc==(p->funcFlags & SQLITE_FUNC_ENCMASK) ){
+    match += 2;  /* Exact encoding match */
+  }else if( (enc & p->funcFlags & 2)!=0 ){
+    match += 1;  /* Both are UTF16, but with different byte orders */
+  }
+
+  return match;
+}
+
+/*
+** Search a FuncDefHash for a function with the given name.  Return
+** a pointer to the matching FuncDef if found, or 0 if there is no match.
+*/
+SQLITE_PRIVATE FuncDef *sqlite3FunctionSearch(
+  int h,               /* Hash of the name */
+  const char *zFunc    /* Name of function */
+){
+  FuncDef *p;
+  for(p=sqlite3BuiltinFunctions.a[h]; p; p=p->u.pHash){
+    assert( p->funcFlags & SQLITE_FUNC_BUILTIN );
+    if( sqlite3StrICmp(p->zName, zFunc)==0 ){
+      return p;
+    }
+  }
+  return 0;
+}
+
+/*
+** Insert a new FuncDef into a FuncDefHash hash table.
+*/
+SQLITE_PRIVATE void sqlite3InsertBuiltinFuncs(
+  FuncDef *aDef,      /* List of global functions to be inserted */
+  int nDef            /* Length of the apDef[] list */
+){
+  int i;
+  for(i=0; i<nDef; i++){
+    FuncDef *pOther;
+    const char *zName = aDef[i].zName;
+    int nName = sqlite3Strlen30(zName);
+    int h = SQLITE_FUNC_HASH(zName[0], nName);
+    assert( aDef[i].funcFlags & SQLITE_FUNC_BUILTIN );
+    pOther = sqlite3FunctionSearch(h, zName);
+    if( pOther ){
+      assert( pOther!=&aDef[i] && pOther->pNext!=&aDef[i] );
+      aDef[i].pNext = pOther->pNext;
+      pOther->pNext = &aDef[i];
+    }else{
+      aDef[i].pNext = 0;
+      aDef[i].u.pHash = sqlite3BuiltinFunctions.a[h];
+      sqlite3BuiltinFunctions.a[h] = &aDef[i];
+    }
+  }
+}
+
+
+
+/*
+** Locate a user function given a name, a number of arguments and a flag
+** indicating whether the function prefers UTF-16 over UTF-8.  Return a
+** pointer to the FuncDef structure that defines that function, or return
+** NULL if the function does not exist.
+**
+** If the createFlag argument is true, then a new (blank) FuncDef
+** structure is created and liked into the "db" structure if a
+** no matching function previously existed.
+**
+** If nArg is -2, then the first valid function found is returned.  A
+** function is valid if xSFunc is non-zero.  The nArg==(-2)
+** case is used to see if zName is a valid function name for some number
+** of arguments.  If nArg is -2, then createFlag must be 0.
+**
+** If createFlag is false, then a function with the required name and
+** number of arguments may be returned even if the eTextRep flag does not
+** match that requested.
+*/
+SQLITE_PRIVATE FuncDef *sqlite3FindFunction(
+  sqlite3 *db,       /* An open database */
+  const char *zName, /* Name of the function.  zero-terminated */
+  int nArg,          /* Number of arguments.  -1 means any number */
+  u8 enc,            /* Preferred text encoding */
+  u8 createFlag      /* Create new entry if true and does not otherwise exist */
+){
+  FuncDef *p;         /* Iterator variable */
+  FuncDef *pBest = 0; /* Best match found so far */
+  int bestScore = 0;  /* Score of best match */
+  int h;              /* Hash value */
+  int nName;          /* Length of the name */
+
+  assert( nArg>=(-2) );
+  assert( nArg>=(-1) || createFlag==0 );
+  nName = sqlite3Strlen30(zName);
+
+  /* First search for a match amongst the application-defined functions.
+  */
+  p = (FuncDef*)sqlite3HashFind(&db->aFunc, zName);
+  while( p ){
+    int score = matchQuality(p, nArg, enc);
+    if( score>bestScore ){
+      pBest = p;
+      bestScore = score;
+    }
+    p = p->pNext;
+  }
+
+  /* If no match is found, search the built-in functions.
+  **
+  ** If the DBFLAG_PreferBuiltin flag is set, then search the built-in
+  ** functions even if a prior app-defined function was found.  And give
+  ** priority to built-in functions.
+  **
+  ** Except, if createFlag is true, that means that we are trying to
+  ** install a new function.  Whatever FuncDef structure is returned it will
+  ** have fields overwritten with new information appropriate for the
+  ** new function.  But the FuncDefs for built-in functions are read-only.
+  ** So we must not search for built-ins when creating a new function.
+  */
+  if( !createFlag && (pBest==0 || (db->mDbFlags & DBFLAG_PreferBuiltin)!=0) ){
+    bestScore = 0;
+    h = SQLITE_FUNC_HASH(sqlite3UpperToLower[(u8)zName[0]], nName);
+    p = sqlite3FunctionSearch(h, zName);
+    while( p ){
+      int score = matchQuality(p, nArg, enc);
+      if( score>bestScore ){
+        pBest = p;
+        bestScore = score;
+      }
+      p = p->pNext;
+    }
+  }
+
+  /* If the createFlag parameter is true and the search did not reveal an
+  ** exact match for the name, number of arguments and encoding, then add a
+  ** new entry to the hash table and return it.
+  */
+  if( createFlag && bestScore<FUNC_PERFECT_MATCH &&
+      (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
+    FuncDef *pOther;
+    u8 *z;
+    pBest->zName = (const char*)&pBest[1];
+    pBest->nArg = (u16)nArg;
+    pBest->funcFlags = enc;
+    memcpy((char*)&pBest[1], zName, nName+1);
+    for(z=(u8*)pBest->zName; *z; z++) *z = sqlite3UpperToLower[*z];
+    pOther = (FuncDef*)sqlite3HashInsert(&db->aFunc, pBest->zName, pBest);
+    if( pOther==pBest ){
+      sqlite3DbFree(db, pBest);
+      sqlite3OomFault(db);
+      return 0;
+    }else{
+      pBest->pNext = pOther;
+    }
+  }
+
+  if( pBest && (pBest->xSFunc || createFlag) ){
+    return pBest;
+  }
+  return 0;
+}
+
+/*
+** Free all resources held by the schema structure. The void* argument points
+** at a Schema struct. This function does not call sqlite3DbFree(db, ) on the
+** pointer itself, it just cleans up subsidiary resources (i.e. the contents
+** of the schema hash tables).
+**
+** The Schema.cache_size variable is not cleared.
+*/
+SQLITE_PRIVATE void sqlite3SchemaClear(void *p){
+  Hash temp1;
+  Hash temp2;
+  HashElem *pElem;
+  Schema *pSchema = (Schema *)p;
+  sqlite3 xdb;
+
+  memset(&xdb, 0, sizeof(xdb));
+  temp1 = pSchema->tblHash;
+  temp2 = pSchema->trigHash;
+  sqlite3HashInit(&pSchema->trigHash);
+  sqlite3HashClear(&pSchema->idxHash);
+  for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){
+    sqlite3DeleteTrigger(&xdb, (Trigger*)sqliteHashData(pElem));
+  }
+  sqlite3HashClear(&temp2);
+  sqlite3HashInit(&pSchema->tblHash);
+  for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){
+    Table *pTab = sqliteHashData(pElem);
+    sqlite3DeleteTable(&xdb, pTab);
+  }
+  sqlite3HashClear(&temp1);
+  sqlite3HashClear(&pSchema->fkeyHash);
+  pSchema->pSeqTab = 0;
+  if( pSchema->schemaFlags & DB_SchemaLoaded ){
+    pSchema->iGeneration++;
+  }
+  pSchema->schemaFlags &= ~(DB_SchemaLoaded|DB_ResetWanted);
+}
+
+/*
+** Find and return the schema associated with a BTree.  Create
+** a new one if necessary.
+*/
+SQLITE_PRIVATE Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
+  Schema * p;
+  if( pBt ){
+    p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear);
+  }else{
+    p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema));
+  }
+  if( !p ){
+    sqlite3OomFault(db);
+  }else if ( 0==p->file_format ){
+    sqlite3HashInit(&p->tblHash);
+    sqlite3HashInit(&p->idxHash);
+    sqlite3HashInit(&p->trigHash);
+    sqlite3HashInit(&p->fkeyHash);
+    p->enc = SQLITE_UTF8;
+  }
+  return p;
+}
+
+/************** End of callback.c ********************************************/
+/************** Begin file delete.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** in order to generate code for DELETE FROM statements.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** While a SrcList can in general represent multiple tables and subqueries
+** (as in the FROM clause of a SELECT statement) in this case it contains
+** the name of a single table, as one might find in an INSERT, DELETE,
+** or UPDATE statement.  Look up that table in the symbol table and
+** return a pointer.  Set an error message and return NULL if the table
+** name is not found or if any other error occurs.
+**
+** The following fields are initialized appropriate in pSrc:
+**
+**    pSrc->a[0].spTab        Pointer to the Table object
+**    pSrc->a[0].u2.pIBIndex  Pointer to the INDEXED BY index, if there is one
+**
+*/
+SQLITE_PRIVATE Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
+  SrcItem *pItem = pSrc->a;
+  Table *pTab;
+  assert( pItem && pSrc->nSrc>=1 );
+  pTab = sqlite3LocateTableItem(pParse, 0, pItem);
+  if( pItem->pSTab ) sqlite3DeleteTable(pParse->db, pItem->pSTab);
+  pItem->pSTab = pTab;
+  pItem->fg.notCte = 1;
+  if( pTab ){
+    pTab->nTabRef++;
+    if( pItem->fg.isIndexedBy && sqlite3IndexedByLookup(pParse, pItem) ){
+      pTab = 0;
+    }
+  }
+  return pTab;
+}
+
+/* Generate byte-code that will report the number of rows modified
+** by a DELETE, INSERT, or UPDATE statement.
+*/
+SQLITE_PRIVATE void sqlite3CodeChangeCount(Vdbe *v, int regCounter, const char *zColName){
+  sqlite3VdbeAddOp0(v, OP_FkCheck);
+  sqlite3VdbeAddOp2(v, OP_ResultRow, regCounter, 1);
+  sqlite3VdbeSetNumCols(v, 1);
+  sqlite3VdbeSetColName(v, 0, COLNAME_NAME, zColName, SQLITE_STATIC);
+}
+
+/* Return true if table pTab is read-only.
+**
+** A table is read-only if any of the following are true:
+**
+**   1) It is a virtual table and no implementation of the xUpdate method
+**      has been provided
+**
+**   2) A trigger is currently being coded and the table is a virtual table
+**      that is SQLITE_VTAB_DIRECTONLY or if PRAGMA trusted_schema=OFF and
+**      the table is not SQLITE_VTAB_INNOCUOUS.
+**
+**   3) It is a system table (i.e. sqlite_schema), this call is not
+**      part of a nested parse and writable_schema pragma has not
+**      been specified
+**
+**   4) The table is a shadow table, the database connection is in
+**      defensive mode, and the current sqlite3_prepare()
+**      is for a top-level SQL statement.
+*/
+static int vtabIsReadOnly(Parse *pParse, Table *pTab){
+  assert( IsVirtual(pTab) );
+  if( sqlite3GetVTable(pParse->db, pTab)->pMod->pModule->xUpdate==0 ){
+    return 1;
+  }
+
+  /* Within triggers:
+  **   *  Do not allow DELETE, INSERT, or UPDATE of SQLITE_VTAB_DIRECTONLY
+  **      virtual tables
+  **   *  Only allow DELETE, INSERT, or UPDATE of non-SQLITE_VTAB_INNOCUOUS
+  **      virtual tables if PRAGMA trusted_schema=ON.
+  */
+  if( pParse->pToplevel!=0
+   && pTab->u.vtab.p->eVtabRisk >
+           ((pParse->db->flags & SQLITE_TrustedSchema)!=0)
+  ){
+    sqlite3ErrorMsg(pParse, "unsafe use of virtual table \"%s\"",
+      pTab->zName);
+  }
+  return 0;
+}
+static int tabIsReadOnly(Parse *pParse, Table *pTab){
+  sqlite3 *db;
+  if( IsVirtual(pTab) ){
+    return vtabIsReadOnly(pParse, pTab);
+  }
+  if( (pTab->tabFlags & (TF_Readonly|TF_Shadow))==0 ) return 0;
+  db = pParse->db;
+  if( (pTab->tabFlags & TF_Readonly)!=0 ){
+    return sqlite3WritableSchema(db)==0 && pParse->nested==0;
+  }
+  assert( pTab->tabFlags & TF_Shadow );
+  return sqlite3ReadOnlyShadowTables(db);
+}
+
+/*
+** Check to make sure the given table is writable.
+**
+** If pTab is not writable  ->  generate an error message and return 1.
+** If pTab is writable but other errors have occurred -> return 1.
+** If pTab is writable and no prior errors -> return 0;
+*/
+SQLITE_PRIVATE int sqlite3IsReadOnly(Parse *pParse, Table *pTab, Trigger *pTrigger){
+  if( tabIsReadOnly(pParse, pTab) ){
+    sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
+    return 1;
+  }
+#ifndef SQLITE_OMIT_VIEW
+  if( IsView(pTab)
+   && (pTrigger==0 || (pTrigger->bReturning && pTrigger->pNext==0))
+  ){
+    sqlite3ErrorMsg(pParse,"cannot modify %s because it is a view",pTab->zName);
+    return 1;
+  }
+#endif
+  return 0;
+}
+
+
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+/*
+** Evaluate a view and store its result in an ephemeral table.  The
+** pWhere argument is an optional WHERE clause that restricts the
+** set of rows in the view that are to be added to the ephemeral table.
+*/
+SQLITE_PRIVATE void sqlite3MaterializeView(
+  Parse *pParse,       /* Parsing context */
+  Table *pView,        /* View definition */
+  Expr *pWhere,        /* Optional WHERE clause to be added */
+  ExprList *pOrderBy,  /* Optional ORDER BY clause */
+  Expr *pLimit,        /* Optional LIMIT clause */
+  int iCur             /* Cursor number for ephemeral table */
+){
+  SelectDest dest;
+  Select *pSel;
+  SrcList *pFrom;
+  sqlite3 *db = pParse->db;
+  int iDb = sqlite3SchemaToIndex(db, pView->pSchema);
+  pWhere = sqlite3ExprDup(db, pWhere, 0);
+  pFrom = sqlite3SrcListAppend(pParse, 0, 0, 0);
+  if( pFrom ){
+    assert( pFrom->nSrc==1 );
+    pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName);
+    assert( pFrom->a[0].fg.fixedSchema==0 && pFrom->a[0].fg.isSubquery==0 );
+    pFrom->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
+    assert( pFrom->a[0].fg.isUsing==0 );
+    assert( pFrom->a[0].u3.pOn==0 );
+  }
+  pSel = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, pOrderBy,
+                          SF_IncludeHidden, pLimit);
+  sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
+  sqlite3Select(pParse, pSel, &dest);
+  sqlite3SelectDelete(db, pSel);
+}
+#endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */
+
+#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
+/*
+** Generate an expression tree to implement the WHERE, ORDER BY,
+** and LIMIT/OFFSET portion of DELETE and UPDATE statements.
+**
+**     DELETE FROM table_wxyz WHERE a<5 ORDER BY a LIMIT 1;
+**                            \__________________________/
+**                               pLimitWhere (pInClause)
+*/
+SQLITE_PRIVATE Expr *sqlite3LimitWhere(
+  Parse *pParse,               /* The parser context */
+  SrcList *pSrc,               /* the FROM clause -- which tables to scan */
+  Expr *pWhere,                /* The WHERE clause.  May be null */
+  ExprList *pOrderBy,          /* The ORDER BY clause.  May be null */
+  Expr *pLimit,                /* The LIMIT clause.  May be null */
+  char *zStmtType              /* Either DELETE or UPDATE.  For err msgs. */
+){
+  sqlite3 *db = pParse->db;
+  Expr *pLhs = NULL;           /* LHS of IN(SELECT...) operator */
+  Expr *pInClause = NULL;      /* WHERE rowid IN ( select ) */
+  ExprList *pEList = NULL;     /* Expression list containing only pSelectRowid*/
+  SrcList *pSelectSrc = NULL;  /* SELECT rowid FROM x ... (dup of pSrc) */
+  Select *pSelect = NULL;      /* Complete SELECT tree */
+  Table *pTab;
+
+  /* Check that there isn't an ORDER BY without a LIMIT clause.
+  */
+  if( pOrderBy && pLimit==0 ) {
+    sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on %s", zStmtType);
+    sqlite3ExprDelete(pParse->db, pWhere);
+    sqlite3ExprListDelete(pParse->db, pOrderBy);
+    return 0;
+  }
+
+  /* We only need to generate a select expression if there
+  ** is a limit/offset term to enforce.
+  */
+  if( pLimit == 0 ) {
+    return pWhere;
+  }
+
+  /* Generate a select expression tree to enforce the limit/offset
+  ** term for the DELETE or UPDATE statement.  For example:
+  **   DELETE FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
+  ** becomes:
+  **   DELETE FROM table_a WHERE rowid IN (
+  **     SELECT rowid FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
+  **   );
+  */
+
+  pTab = pSrc->a[0].pSTab;
+  if( HasRowid(pTab) ){
+    pLhs = sqlite3PExpr(pParse, TK_ROW, 0, 0);
+    pEList = sqlite3ExprListAppend(
+        pParse, 0, sqlite3PExpr(pParse, TK_ROW, 0, 0)
+    );
+  }else{
+    Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+    assert( pPk!=0 );
+    assert( pPk->nKeyCol>=1 );
+    if( pPk->nKeyCol==1 ){
+      const char *zName;
+      assert( pPk->aiColumn[0]>=0 && pPk->aiColumn[0]<pTab->nCol );
+      zName = pTab->aCol[pPk->aiColumn[0]].zCnName;
+      pLhs = sqlite3Expr(db, TK_ID, zName);
+      pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ID, zName));
+    }else{
+      int i;
+      for(i=0; i<pPk->nKeyCol; i++){
+        Expr *p;
+        assert( pPk->aiColumn[i]>=0 && pPk->aiColumn[i]<pTab->nCol );
+        p = sqlite3Expr(db, TK_ID, pTab->aCol[pPk->aiColumn[i]].zCnName);
+        pEList = sqlite3ExprListAppend(pParse, pEList, p);
+      }
+      pLhs = sqlite3PExpr(pParse, TK_VECTOR, 0, 0);
+      if( pLhs ){
+        pLhs->x.pList = sqlite3ExprListDup(db, pEList, 0);
+      }
+    }
+  }
+
+  /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
+  ** and the SELECT subtree. */
+  pSrc->a[0].pSTab = 0;
+  pSelectSrc = sqlite3SrcListDup(db, pSrc, 0);
+  pSrc->a[0].pSTab = pTab;
+  if( pSrc->a[0].fg.isIndexedBy ){
+    assert( pSrc->a[0].fg.isCte==0 );
+    pSrc->a[0].u2.pIBIndex = 0;
+    pSrc->a[0].fg.isIndexedBy = 0;
+    sqlite3DbFree(db, pSrc->a[0].u1.zIndexedBy);
+  }else if( pSrc->a[0].fg.isCte ){
+    pSrc->a[0].u2.pCteUse->nUse++;
+  }
+
+  /* generate the SELECT expression tree. */
+  pSelect = sqlite3SelectNew(pParse, pEList, pSelectSrc, pWhere, 0 ,0,
+      pOrderBy,0,pLimit
+  );
+
+  /* now generate the new WHERE rowid IN clause for the DELETE/UPDATE */
+  pInClause = sqlite3PExpr(pParse, TK_IN, pLhs, 0);
+  sqlite3PExprAddSelect(pParse, pInClause, pSelect);
+  return pInClause;
+}
+#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) */
+       /*      && !defined(SQLITE_OMIT_SUBQUERY) */
+
+/*
+** Generate code for a DELETE FROM statement.
+**
+**     DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
+**                 \________/       \________________/
+**                  pTabList              pWhere
+*/
+SQLITE_PRIVATE void sqlite3DeleteFrom(
+  Parse *pParse,         /* The parser context */
+  SrcList *pTabList,     /* The table from which we should delete things */
+  Expr *pWhere,          /* The WHERE clause.  May be null */
+  ExprList *pOrderBy,    /* ORDER BY clause. May be null */
+  Expr *pLimit           /* LIMIT clause. May be null */
+){
+  Vdbe *v;               /* The virtual database engine */
+  Table *pTab;           /* The table from which records will be deleted */
+  int i;                 /* Loop counter */
+  WhereInfo *pWInfo;     /* Information about the WHERE clause */
+  Index *pIdx;           /* For looping over indices of the table */
+  int iTabCur;           /* Cursor number for the table */
+  int iDataCur = 0;      /* VDBE cursor for the canonical data source */
+  int iIdxCur = 0;       /* Cursor number of the first index */
+  int nIdx;              /* Number of indices */
+  sqlite3 *db;           /* Main database structure */
+  AuthContext sContext;  /* Authorization context */
+  NameContext sNC;       /* Name context to resolve expressions in */
+  int iDb;               /* Database number */
+  int memCnt = 0;        /* Memory cell used for change counting */
+  int rcauth;            /* Value returned by authorization callback */
+  int eOnePass;          /* ONEPASS_OFF or _SINGLE or _MULTI */
+  int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */
+  u8 *aToOpen = 0;       /* Open cursor iTabCur+j if aToOpen[j] is true */
+  Index *pPk;            /* The PRIMARY KEY index on the table */
+  int iPk = 0;           /* First of nPk registers holding PRIMARY KEY value */
+  i16 nPk = 1;           /* Number of columns in the PRIMARY KEY */
+  int iKey;              /* Memory cell holding key of row to be deleted */
+  i16 nKey;              /* Number of memory cells in the row key */
+  int iEphCur = 0;       /* Ephemeral table holding all primary key values */
+  int iRowSet = 0;       /* Register for rowset of rows to delete */
+  int addrBypass = 0;    /* Address of jump over the delete logic */
+  int addrLoop = 0;      /* Top of the delete loop */
+  int addrEphOpen = 0;   /* Instruction to open the Ephemeral table */
+  int bComplex;          /* True if there are triggers or FKs or
+                         ** subqueries in the WHERE clause */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;                  /* True if attempting to delete from a view */
+  Trigger *pTrigger;           /* List of table triggers, if required */
+#endif
+
+  memset(&sContext, 0, sizeof(sContext));
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nErr ){
+    goto delete_from_cleanup;
+  }
+  assert( db->mallocFailed==0 );
+  assert( pTabList->nSrc==1 );
+
+  /* Locate the table which we want to delete.  This table has to be
+  ** put in an SrcList structure because some of the subroutines we
+  ** will be calling are designed to work with multiple tables and expect
+  ** an SrcList* parameter instead of just a Table* parameter.
+  */
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 )  goto delete_from_cleanup;
+
+  /* Figure out if we have any triggers and if the table being
+  ** deleted from is a view
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
+  isView = IsView(pTab);
+#else
+# define pTrigger 0
+# define isView 0
+#endif
+  bComplex = pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0);
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x10000 ){
+    sqlite3TreeViewLine(0, "In sqlite3Delete() at %s:%d", __FILE__, __LINE__);
+    sqlite3TreeViewDelete(pParse->pWith, pTabList, pWhere,
+                          pOrderBy, pLimit, pTrigger);
+  }
+#endif
+
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( !isView ){
+    pWhere = sqlite3LimitWhere(
+        pParse, pTabList, pWhere, pOrderBy, pLimit, "DELETE"
+    );
+    pOrderBy = 0;
+    pLimit = 0;
+  }
+#endif
+
+  /* If pTab is really a view, make sure it has been initialized.
+  */
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto delete_from_cleanup;
+  }
+
+  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
+    goto delete_from_cleanup;
+  }
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb<db->nDb );
+  rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0,
+                            db->aDb[iDb].zDbSName);
+  assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE );
+  if( rcauth==SQLITE_DENY ){
+    goto delete_from_cleanup;
+  }
+  assert(!isView || pTrigger);
+
+  /* Assign cursor numbers to the table and all its indices.
+  */
+  assert( pTabList->nSrc==1 );
+  iTabCur = pTabList->a[0].iCursor = pParse->nTab++;
+  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
+    pParse->nTab++;
+  }
+
+  /* Start the view context
+  */
+  if( isView ){
+    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
+  }
+
+  /* Begin generating code.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ){
+    goto delete_from_cleanup;
+  }
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, bComplex, iDb);
+
+  /* If we are trying to delete from a view, realize that view into
+  ** an ephemeral table.
+  */
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+  if( isView ){
+    sqlite3MaterializeView(pParse, pTab,
+        pWhere, pOrderBy, pLimit, iTabCur
+    );
+    iDataCur = iIdxCur = iTabCur;
+    pOrderBy = 0;
+    pLimit = 0;
+  }
+#endif
+
+  /* Resolve the column names in the WHERE clause.
+  */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  sNC.pSrcList = pTabList;
+  if( sqlite3ResolveExprNames(&sNC, pWhere) ){
+    goto delete_from_cleanup;
+  }
+
+  /* Initialize the counter of the number of rows deleted, if
+  ** we are counting rows.
+  */
+  if( (db->flags & SQLITE_CountRows)!=0
+   && !pParse->nested
+   && !pParse->pTriggerTab
+   && !pParse->bReturning
+  ){
+    memCnt = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt);
+  }
+
+#ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
+  /* Special case: A DELETE without a WHERE clause deletes everything.
+  ** It is easier just to erase the whole table. Prior to version 3.6.5,
+  ** this optimization caused the row change count (the value returned by
+  ** API function sqlite3_count_changes) to be set incorrectly.
+  **
+  ** The "rcauth==SQLITE_OK" terms is the
+  ** IMPLEMENTATION-OF: R-17228-37124 If the action code is SQLITE_DELETE and
+  ** the callback returns SQLITE_IGNORE then the DELETE operation proceeds but
+  ** the truncate optimization is disabled and all rows are deleted
+  ** individually.
+  */
+  if( rcauth==SQLITE_OK
+   && pWhere==0
+   && !bComplex
+   && !IsVirtual(pTab)
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+   && db->xPreUpdateCallback==0
+#endif
+  ){
+    assert( !isView );
+    sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName);
+    if( HasRowid(pTab) ){
+      sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt ? memCnt : -1,
+                        pTab->zName, P4_STATIC);
+    }
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      assert( pIdx->pSchema==pTab->pSchema );
+      if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
+        sqlite3VdbeAddOp3(v, OP_Clear, pIdx->tnum, iDb, memCnt ? memCnt : -1);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb);
+      }
+    }
+  }else
+#endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */
+  {
+    u16 wcf = WHERE_ONEPASS_DESIRED|WHERE_DUPLICATES_OK;
+    if( sNC.ncFlags & NC_Subquery ) bComplex = 1;
+    wcf |= (bComplex ? 0 : WHERE_ONEPASS_MULTIROW);
+    if( HasRowid(pTab) ){
+      /* For a rowid table, initialize the RowSet to an empty set */
+      pPk = 0;
+      assert( nPk==1 );
+      iRowSet = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
+    }else{
+      /* For a WITHOUT ROWID table, create an ephemeral table used to
+      ** hold all primary keys for rows to be deleted. */
+      pPk = sqlite3PrimaryKeyIndex(pTab);
+      assert( pPk!=0 );
+      nPk = pPk->nKeyCol;
+      iPk = pParse->nMem+1;
+      pParse->nMem += nPk;
+      iEphCur = pParse->nTab++;
+      addrEphOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEphCur, nPk);
+      sqlite3VdbeSetP4KeyInfo(pParse, pPk);
+    }
+
+    /* Construct a query to find the rowid or primary key for every row
+    ** to be deleted, based on the WHERE clause. Set variable eOnePass
+    ** to indicate the strategy used to implement this delete:
+    **
+    **  ONEPASS_OFF:    Two-pass approach - use a FIFO for rowids/PK values.
+    **  ONEPASS_SINGLE: One-pass approach - at most one row deleted.
+    **  ONEPASS_MULTI:  One-pass approach - any number of rows may be deleted.
+    */
+    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0,0,wcf,iTabCur+1);
+    if( pWInfo==0 ) goto delete_from_cleanup;
+    eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
+    assert( IsVirtual(pTab)==0 || eOnePass!=ONEPASS_MULTI );
+    assert( IsVirtual(pTab) || bComplex || eOnePass!=ONEPASS_OFF
+            || OptimizationDisabled(db, SQLITE_OnePass) );
+    if( eOnePass!=ONEPASS_SINGLE ) sqlite3MultiWrite(pParse);
+    if( sqlite3WhereUsesDeferredSeek(pWInfo) ){
+      sqlite3VdbeAddOp1(v, OP_FinishSeek, iTabCur);
+    }
+
+    /* Keep track of the number of rows to be deleted */
+    if( memCnt ){
+      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
+    }
+
+    /* Extract the rowid or primary key for the current row */
+    if( pPk ){
+      for(i=0; i<nPk; i++){
+        assert( pPk->aiColumn[i]>=0 );
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur,
+                                        pPk->aiColumn[i], iPk+i);
+      }
+      iKey = iPk;
+    }else{
+      iKey = ++pParse->nMem;
+      sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, -1, iKey);
+    }
+
+    if( eOnePass!=ONEPASS_OFF ){
+      /* For ONEPASS, no need to store the rowid/primary-key. There is only
+      ** one, so just keep it in its register(s) and fall through to the
+      ** delete code.  */
+      nKey = nPk; /* OP_Found will use an unpacked key */
+      aToOpen = sqlite3DbMallocRawNN(db, nIdx+2);
+      if( aToOpen==0 ){
+        sqlite3WhereEnd(pWInfo);
+        goto delete_from_cleanup;
+      }
+      memset(aToOpen, 1, nIdx+1);
+      aToOpen[nIdx+1] = 0;
+      if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iTabCur] = 0;
+      if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iTabCur] = 0;
+      if( addrEphOpen ) sqlite3VdbeChangeToNoop(v, addrEphOpen);
+      addrBypass = sqlite3VdbeMakeLabel(pParse);
+    }else{
+      if( pPk ){
+        /* Add the PK key for this row to the temporary table */
+        iKey = ++pParse->nMem;
+        nKey = 0;   /* Zero tells OP_Found to use a composite key */
+        sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, iKey,
+            sqlite3IndexAffinityStr(pParse->db, pPk), nPk);
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEphCur, iKey, iPk, nPk);
+      }else{
+        /* Add the rowid of the row to be deleted to the RowSet */
+        nKey = 1;  /* OP_DeferredSeek always uses a single rowid */
+        sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, iKey);
+      }
+      sqlite3WhereEnd(pWInfo);
+    }
+
+    /* Unless this is a view, open cursors for the table we are
+    ** deleting from and all its indices. If this is a view, then the
+    ** only effect this statement has is to fire the INSTEAD OF
+    ** triggers.
+    */
+    if( !isView ){
+      int iAddrOnce = 0;
+      if( eOnePass==ONEPASS_MULTI ){
+        iAddrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+      }
+      testcase( IsVirtual(pTab) );
+      sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, OPFLAG_FORDELETE,
+                                 iTabCur, aToOpen, &iDataCur, &iIdxCur);
+      assert( pPk || IsVirtual(pTab) || iDataCur==iTabCur );
+      assert( pPk || IsVirtual(pTab) || iIdxCur==iDataCur+1 );
+      if( eOnePass==ONEPASS_MULTI ){
+        sqlite3VdbeJumpHereOrPopInst(v, iAddrOnce);
+      }
+    }
+
+    /* Set up a loop over the rowids/primary-keys that were found in the
+    ** where-clause loop above.
+    */
+    if( eOnePass!=ONEPASS_OFF ){
+      assert( nKey==nPk );  /* OP_Found will use an unpacked key */
+      if( !IsVirtual(pTab) && aToOpen[iDataCur-iTabCur] ){
+        assert( pPk!=0 || IsView(pTab) );
+        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey);
+        VdbeCoverage(v);
+      }
+    }else if( pPk ){
+      addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur); VdbeCoverage(v);
+      if( IsVirtual(pTab) ){
+        sqlite3VdbeAddOp3(v, OP_Column, iEphCur, 0, iKey);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_RowData, iEphCur, iKey);
+      }
+      assert( nKey==0 );  /* OP_Found will use a composite key */
+    }else{
+      addrLoop = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, 0, iKey);
+      VdbeCoverage(v);
+      assert( nKey==1 );
+    }
+
+    /* Delete the row */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( IsVirtual(pTab) ){
+      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
+      sqlite3VtabMakeWritable(pParse, pTab);
+      assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE );
+      sqlite3MayAbort(pParse);
+      if( eOnePass==ONEPASS_SINGLE ){
+        sqlite3VdbeAddOp1(v, OP_Close, iTabCur);
+        if( sqlite3IsToplevel(pParse) ){
+          pParse->isMultiWrite = 0;
+        }
+      }
+      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iKey, pVTab, P4_VTAB);
+      sqlite3VdbeChangeP5(v, OE_Abort);
+    }else
+#endif
+    {
+      int count = (pParse->nested==0);    /* True to count changes */
+      sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
+          iKey, nKey, count, OE_Default, eOnePass, aiCurOnePass[1]);
+    }
+
+    /* End of the loop over all rowids/primary-keys. */
+    if( eOnePass!=ONEPASS_OFF ){
+      sqlite3VdbeResolveLabel(v, addrBypass);
+      sqlite3WhereEnd(pWInfo);
+    }else if( pPk ){
+      sqlite3VdbeAddOp2(v, OP_Next, iEphCur, addrLoop+1); VdbeCoverage(v);
+      sqlite3VdbeJumpHere(v, addrLoop);
+    }else{
+      sqlite3VdbeGoto(v, addrLoop);
+      sqlite3VdbeJumpHere(v, addrLoop);
+    }
+  } /* End non-truncate path */
+
+  /* Update the sqlite_sequence table by storing the content of the
+  ** maximum rowid counter values recorded while inserting into
+  ** autoincrement tables.
+  */
+  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
+    sqlite3AutoincrementEnd(pParse);
+  }
+
+  /* Return the number of rows that were deleted. If this routine is
+  ** generating code because of a call to sqlite3NestedParse(), do not
+  ** invoke the callback function.
+  */
+  if( memCnt ){
+    sqlite3CodeChangeCount(v, memCnt, "rows deleted");
+  }
+
+delete_from_cleanup:
+  sqlite3AuthContextPop(&sContext);
+  sqlite3SrcListDelete(db, pTabList);
+  sqlite3ExprDelete(db, pWhere);
+#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT)
+  sqlite3ExprListDelete(db, pOrderBy);
+  sqlite3ExprDelete(db, pLimit);
+#endif
+  if( aToOpen ) sqlite3DbNNFreeNN(db, aToOpen);
+  return;
+}
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** they may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
+
+/*
+** This routine generates VDBE code that causes a single row of a
+** single table to be deleted.  Both the original table entry and
+** all indices are removed.
+**
+** Preconditions:
+**
+**   1.  iDataCur is an open cursor on the btree that is the canonical data
+**       store for the table.  (This will be either the table itself,
+**       in the case of a rowid table, or the PRIMARY KEY index in the case
+**       of a WITHOUT ROWID table.)
+**
+**   2.  Read/write cursors for all indices of pTab must be open as
+**       cursor number iIdxCur+i for the i-th index.
+**
+**   3.  The primary key for the row to be deleted must be stored in a
+**       sequence of nPk memory cells starting at iPk.  If nPk==0 that means
+**       that a search record formed from OP_MakeRecord is contained in the
+**       single memory location iPk.
+**
+** eMode:
+**   Parameter eMode may be passed either ONEPASS_OFF (0), ONEPASS_SINGLE, or
+**   ONEPASS_MULTI.  If eMode is not ONEPASS_OFF, then the cursor
+**   iDataCur already points to the row to delete. If eMode is ONEPASS_OFF
+**   then this function must seek iDataCur to the entry identified by iPk
+**   and nPk before reading from it.
+**
+**   If eMode is ONEPASS_MULTI, then this call is being made as part
+**   of a ONEPASS delete that affects multiple rows. In this case, if
+**   iIdxNoSeek is a valid cursor number (>=0) and is not the same as
+**   iDataCur, then its position should be preserved following the delete
+**   operation. Or, if iIdxNoSeek is not a valid cursor number, the
+**   position of iDataCur should be preserved instead.
+**
+** iIdxNoSeek:
+**   If iIdxNoSeek is a valid cursor number (>=0) not equal to iDataCur,
+**   then it identifies an index cursor (from within array of cursors
+**   starting at iIdxCur) that already points to the index entry to be deleted.
+**   Except, this optimization is disabled if there are BEFORE triggers since
+**   the trigger body might have moved the cursor.
+*/
+SQLITE_PRIVATE void sqlite3GenerateRowDelete(
+  Parse *pParse,     /* Parsing context */
+  Table *pTab,       /* Table containing the row to be deleted */
+  Trigger *pTrigger, /* List of triggers to (potentially) fire */
+  int iDataCur,      /* Cursor from which column data is extracted */
+  int iIdxCur,       /* First index cursor */
+  int iPk,           /* First memory cell containing the PRIMARY KEY */
+  i16 nPk,           /* Number of PRIMARY KEY memory cells */
+  u8 count,          /* If non-zero, increment the row change counter */
+  u8 onconf,         /* Default ON CONFLICT policy for triggers */
+  u8 eMode,          /* ONEPASS_OFF, _SINGLE, or _MULTI.  See above */
+  int iIdxNoSeek     /* Cursor number of cursor that does not need seeking */
+){
+  Vdbe *v = pParse->pVdbe;        /* Vdbe */
+  int iOld = 0;                   /* First register in OLD.* array */
+  int iLabel;                     /* Label resolved to end of generated code */
+  u8 opSeek;                      /* Seek opcode */
+
+  /* Vdbe is guaranteed to have been allocated by this stage. */
+  assert( v );
+  VdbeModuleComment((v, "BEGIN: GenRowDel(%d,%d,%d,%d)",
+                         iDataCur, iIdxCur, iPk, (int)nPk));
+
+  /* Seek cursor iCur to the row to delete. If this row no longer exists
+  ** (this can happen if a trigger program has already deleted it), do
+  ** not attempt to delete it or fire any DELETE triggers.  */
+  iLabel = sqlite3VdbeMakeLabel(pParse);
+  opSeek = HasRowid(pTab) ? OP_NotExists : OP_NotFound;
+  if( eMode==ONEPASS_OFF ){
+    sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
+    VdbeCoverageIf(v, opSeek==OP_NotExists);
+    VdbeCoverageIf(v, opSeek==OP_NotFound);
+  }
+
+  /* If there are any triggers to fire, allocate a range of registers to
+  ** use for the old.* references in the triggers.  */
+  if( sqlite3FkRequired(pParse, pTab, 0, 0) || pTrigger ){
+    u32 mask;                     /* Mask of OLD.* columns in use */
+    int iCol;                     /* Iterator used while populating OLD.* */
+    int addrStart;                /* Start of BEFORE trigger programs */
+
+    /* TODO: Could use temporary registers here. Also could attempt to
+    ** avoid copying the contents of the rowid register.  */
+    mask = sqlite3TriggerColmask(
+        pParse, pTrigger, 0, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onconf
+    );
+    mask |= sqlite3FkOldmask(pParse, pTab);
+    iOld = pParse->nMem+1;
+    pParse->nMem += (1 + pTab->nCol);
+
+    /* Populate the OLD.* pseudo-table register array. These values will be
+    ** used by any BEFORE and AFTER triggers that exist.  */
+    sqlite3VdbeAddOp2(v, OP_Copy, iPk, iOld);
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      testcase( mask!=0xffffffff && iCol==31 );
+      testcase( mask!=0xffffffff && iCol==32 );
+      if( mask==0xffffffff || (iCol<=31 && (mask & MASKBIT32(iCol))!=0) ){
+        int kk = sqlite3TableColumnToStorage(pTab, iCol);
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, iCol, iOld+kk+1);
+      }
+    }
+
+    /* Invoke BEFORE DELETE trigger programs. */
+    addrStart = sqlite3VdbeCurrentAddr(v);
+    sqlite3CodeRowTrigger(pParse, pTrigger,
+        TK_DELETE, 0, TRIGGER_BEFORE, pTab, iOld, onconf, iLabel
+    );
+
+    /* If any BEFORE triggers were coded, then seek the cursor to the
+    ** row to be deleted again. It may be that the BEFORE triggers moved
+    ** the cursor or already deleted the row that the cursor was
+    ** pointing to.
+    **
+    ** Also disable the iIdxNoSeek optimization since the BEFORE trigger
+    ** may have moved that cursor.
+    */
+    if( addrStart<sqlite3VdbeCurrentAddr(v) ){
+      sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
+      VdbeCoverageIf(v, opSeek==OP_NotExists);
+      VdbeCoverageIf(v, opSeek==OP_NotFound);
+      testcase( iIdxNoSeek>=0 );
+      iIdxNoSeek = -1;
+    }
+
+    /* Do FK processing. This call checks that any FK constraints that
+    ** refer to this table (i.e. constraints attached to other tables)
+    ** are not violated by deleting this row.  */
+    sqlite3FkCheck(pParse, pTab, iOld, 0, 0, 0);
+  }
+
+  /* Delete the index and table entries. Skip this step if pTab is really
+  ** a view (in which case the only effect of the DELETE statement is to
+  ** fire the INSTEAD OF triggers).
+  **
+  ** If variable 'count' is non-zero, then this OP_Delete instruction should
+  ** invoke the update-hook. The pre-update-hook, on the other hand should
+  ** be invoked unless table pTab is a system table. The difference is that
+  ** the update-hook is not invoked for rows removed by REPLACE, but the
+  ** pre-update-hook is.
+  */
+  if( !IsView(pTab) ){
+    u8 p5 = 0;
+    sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,iIdxNoSeek);
+    sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, (count?OPFLAG_NCHANGE:0));
+    if( pParse->nested==0 || 0==sqlite3_stricmp(pTab->zName, "sqlite_stat1") ){
+      sqlite3VdbeAppendP4(v, (char*)pTab, P4_TABLE);
+    }
+    if( eMode!=ONEPASS_OFF ){
+      sqlite3VdbeChangeP5(v, OPFLAG_AUXDELETE);
+    }
+    if( iIdxNoSeek>=0 && iIdxNoSeek!=iDataCur ){
+      sqlite3VdbeAddOp1(v, OP_Delete, iIdxNoSeek);
+    }
+    if( eMode==ONEPASS_MULTI ) p5 |= OPFLAG_SAVEPOSITION;
+    sqlite3VdbeChangeP5(v, p5);
+  }
+
+  /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
+  ** handle rows (possibly in other tables) that refer via a foreign key
+  ** to the row just deleted. */
+  sqlite3FkActions(pParse, pTab, 0, iOld, 0, 0);
+
+  /* Invoke AFTER DELETE trigger programs. */
+  if( pTrigger ){
+    sqlite3CodeRowTrigger(pParse, pTrigger,
+        TK_DELETE, 0, TRIGGER_AFTER, pTab, iOld, onconf, iLabel
+    );
+  }
+
+  /* Jump here if the row had already been deleted before any BEFORE
+  ** trigger programs were invoked. Or if a trigger program throws a
+  ** RAISE(IGNORE) exception.  */
+  sqlite3VdbeResolveLabel(v, iLabel);
+  VdbeModuleComment((v, "END: GenRowDel()"));
+}
+
+/*
+** This routine generates VDBE code that causes the deletion of all
+** index entries associated with a single row of a single table, pTab
+**
+** Preconditions:
+**
+**   1.  A read/write cursor "iDataCur" must be open on the canonical storage
+**       btree for the table pTab.  (This will be either the table itself
+**       for rowid tables or to the primary key index for WITHOUT ROWID
+**       tables.)
+**
+**   2.  Read/write cursors for all indices of pTab must be open as
+**       cursor number iIdxCur+i for the i-th index.  (The pTab->pIndex
+**       index is the 0-th index.)
+**
+**   3.  The "iDataCur" cursor must be already be positioned on the row
+**       that is to be deleted.
+*/
+SQLITE_PRIVATE void sqlite3GenerateRowIndexDelete(
+  Parse *pParse,     /* Parsing and code generating context */
+  Table *pTab,       /* Table containing the row to be deleted */
+  int iDataCur,      /* Cursor of table holding data. */
+  int iIdxCur,       /* First index cursor */
+  int *aRegIdx,      /* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */
+  int iIdxNoSeek     /* Do not delete from this cursor */
+){
+  int i;             /* Index loop counter */
+  int r1 = -1;       /* Register holding an index key */
+  int iPartIdxLabel; /* Jump destination for skipping partial index entries */
+  Index *pIdx;       /* Current index */
+  Index *pPrior = 0; /* Prior index */
+  Vdbe *v;           /* The prepared statement under construction */
+  Index *pPk;        /* PRIMARY KEY index, or NULL for rowid tables */
+
+  v = pParse->pVdbe;
+  pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
+  for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
+    assert( iIdxCur+i!=iDataCur || pPk==pIdx );
+    if( aRegIdx!=0 && aRegIdx[i]==0 ) continue;
+    if( pIdx==pPk ) continue;
+    if( iIdxCur+i==iIdxNoSeek ) continue;
+    VdbeModuleComment((v, "GenRowIdxDel for %s", pIdx->zName));
+    r1 = sqlite3GenerateIndexKey(pParse, pIdx, iDataCur, 0, 1,
+        &iPartIdxLabel, pPrior, r1);
+    sqlite3VdbeAddOp3(v, OP_IdxDelete, iIdxCur+i, r1,
+        pIdx->uniqNotNull ? pIdx->nKeyCol : pIdx->nColumn);
+    sqlite3VdbeChangeP5(v, 1);  /* Cause IdxDelete to error if no entry found */
+    sqlite3ResolvePartIdxLabel(pParse, iPartIdxLabel);
+    pPrior = pIdx;
+  }
+}
+
+/*
+** Generate code that will assemble an index key and stores it in register
+** regOut.  The key with be for index pIdx which is an index on pTab.
+** iCur is the index of a cursor open on the pTab table and pointing to
+** the entry that needs indexing.  If pTab is a WITHOUT ROWID table, then
+** iCur must be the cursor of the PRIMARY KEY index.
+**
+** Return a register number which is the first in a block of
+** registers that holds the elements of the index key.  The
+** block of registers has already been deallocated by the time
+** this routine returns.
+**
+** If *piPartIdxLabel is not NULL, fill it in with a label and jump
+** to that label if pIdx is a partial index that should be skipped.
+** The label should be resolved using sqlite3ResolvePartIdxLabel().
+** A partial index should be skipped if its WHERE clause evaluates
+** to false or null.  If pIdx is not a partial index, *piPartIdxLabel
+** will be set to zero which is an empty label that is ignored by
+** sqlite3ResolvePartIdxLabel().
+**
+** The pPrior and regPrior parameters are used to implement a cache to
+** avoid unnecessary register loads.  If pPrior is not NULL, then it is
+** a pointer to a different index for which an index key has just been
+** computed into register regPrior.  If the current pIdx index is generating
+** its key into the same sequence of registers and if pPrior and pIdx share
+** a column in common, then the register corresponding to that column already
+** holds the correct value and the loading of that register is skipped.
+** This optimization is helpful when doing a DELETE or an INTEGRITY_CHECK
+** on a table with multiple indices, and especially with the ROWID or
+** PRIMARY KEY columns of the index.
+*/
+SQLITE_PRIVATE int sqlite3GenerateIndexKey(
+  Parse *pParse,       /* Parsing context */
+  Index *pIdx,         /* The index for which to generate a key */
+  int iDataCur,        /* Cursor number from which to take column data */
+  int regOut,          /* Put the new key into this register if not 0 */
+  int prefixOnly,      /* Compute only a unique prefix of the key */
+  int *piPartIdxLabel, /* OUT: Jump to this label to skip partial index */
+  Index *pPrior,       /* Previously generated index key */
+  int regPrior         /* Register holding previous generated key */
+){
+  Vdbe *v = pParse->pVdbe;
+  int j;
+  int regBase;
+  int nCol;
+
+  if( piPartIdxLabel ){
+    if( pIdx->pPartIdxWhere ){
+      *piPartIdxLabel = sqlite3VdbeMakeLabel(pParse);
+      pParse->iSelfTab = iDataCur + 1;
+      sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, *piPartIdxLabel,
+                            SQLITE_JUMPIFNULL);
+      pParse->iSelfTab = 0;
+      pPrior = 0; /* Ticket a9efb42811fa41ee 2019-11-02;
+                  ** pPartIdxWhere may have corrupted regPrior registers */
+    }else{
+      *piPartIdxLabel = 0;
+    }
+  }
+  nCol = (prefixOnly && pIdx->uniqNotNull) ? pIdx->nKeyCol : pIdx->nColumn;
+  regBase = sqlite3GetTempRange(pParse, nCol);
+  if( pPrior && (regBase!=regPrior || pPrior->pPartIdxWhere) ) pPrior = 0;
+  for(j=0; j<nCol; j++){
+    if( pPrior
+     && pPrior->aiColumn[j]==pIdx->aiColumn[j]
+     && pPrior->aiColumn[j]!=XN_EXPR
+    ){
+      /* This column was already computed by the previous index */
+      continue;
+    }
+    sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iDataCur, j, regBase+j);
+    if( pIdx->aiColumn[j]>=0 ){
+      /* If the column affinity is REAL but the number is an integer, then it
+      ** might be stored in the table as an integer (using a compact
+      ** representation) then converted to REAL by an OP_RealAffinity opcode.
+      ** But we are getting ready to store this value back into an index, where
+      ** it should be converted by to INTEGER again.  So omit the
+      ** OP_RealAffinity opcode if it is present */
+      sqlite3VdbeDeletePriorOpcode(v, OP_RealAffinity);
+    }
+  }
+  if( regOut ){
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regOut);
+  }
+  sqlite3ReleaseTempRange(pParse, regBase, nCol);
+  return regBase;
+}
+
+/*
+** If a prior call to sqlite3GenerateIndexKey() generated a jump-over label
+** because it was a partial index, then this routine should be called to
+** resolve that label.
+*/
+SQLITE_PRIVATE void sqlite3ResolvePartIdxLabel(Parse *pParse, int iLabel){
+  if( iLabel ){
+    sqlite3VdbeResolveLabel(pParse->pVdbe, iLabel);
+  }
+}
+
+/************** End of delete.c **********************************************/
+/************** Begin file func.c ********************************************/
+/*
+** 2002 February 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C-language implementations for many of the SQL
+** functions of SQLite.  (Some function, and in particular the date and
+** time functions, are implemented separately.)
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdlib.h> */
+/* #include <assert.h> */
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/* #include <math.h> */
+#endif
+/* #include "vdbeInt.h" */
+
+/*
+** Return the collating function associated with a function.
+*/
+static CollSeq *sqlite3GetFuncCollSeq(sqlite3_context *context){
+  VdbeOp *pOp;
+  assert( context->pVdbe!=0 );
+  pOp = &context->pVdbe->aOp[context->iOp-1];
+  assert( pOp->opcode==OP_CollSeq );
+  assert( pOp->p4type==P4_COLLSEQ );
+  return pOp->p4.pColl;
+}
+
+/*
+** Indicate that the accumulator load should be skipped on this
+** iteration of the aggregate loop.
+*/
+static void sqlite3SkipAccumulatorLoad(sqlite3_context *context){
+  assert( context->isError<=0 );
+  context->isError = -1;
+  context->skipFlag = 1;
+}
+
+/*
+** Implementation of the non-aggregate min() and max() functions
+*/
+static void minmaxFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+  int mask;    /* 0 for min() or 0xffffffff for max() */
+  int iBest;
+  CollSeq *pColl;
+
+  assert( argc>1 );
+  mask = sqlite3_user_data(context)==0 ? 0 : -1;
+  pColl = sqlite3GetFuncCollSeq(context);
+  assert( pColl );
+  assert( mask==-1 || mask==0 );
+  iBest = 0;
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  for(i=1; i<argc; i++){
+    if( sqlite3_value_type(argv[i])==SQLITE_NULL ) return;
+    if( (sqlite3MemCompare(argv[iBest], argv[i], pColl)^mask)>=0 ){
+      testcase( mask==0 );
+      iBest = i;
+    }
+  }
+  sqlite3_result_value(context, argv[iBest]);
+}
+
+/*
+** Return the type of the argument.
+*/
+static void typeofFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  static const char *azType[] = { "integer", "real", "text", "blob", "null" };
+  int i = sqlite3_value_type(argv[0]) - 1;
+  UNUSED_PARAMETER(NotUsed);
+  assert( i>=0 && i<ArraySize(azType) );
+  assert( SQLITE_INTEGER==1 );
+  assert( SQLITE_FLOAT==2 );
+  assert( SQLITE_TEXT==3 );
+  assert( SQLITE_BLOB==4 );
+  assert( SQLITE_NULL==5 );
+  /* EVIDENCE-OF: R-01470-60482 The sqlite3_value_type(V) interface returns
+  ** the datatype code for the initial datatype of the sqlite3_value object
+  ** V. The returned value is one of SQLITE_INTEGER, SQLITE_FLOAT,
+  ** SQLITE_TEXT, SQLITE_BLOB, or SQLITE_NULL. */
+  sqlite3_result_text(context, azType[i], -1, SQLITE_STATIC);
+}
+
+/* subtype(X)
+**
+** Return the subtype of X
+*/
+static void subtypeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  UNUSED_PARAMETER(argc);
+  sqlite3_result_int(context, sqlite3_value_subtype(argv[0]));
+}
+
+/*
+** Implementation of the length() function
+*/
+static void lengthFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_BLOB:
+    case SQLITE_INTEGER:
+    case SQLITE_FLOAT: {
+      sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
+      break;
+    }
+    case SQLITE_TEXT: {
+      const unsigned char *z = sqlite3_value_text(argv[0]);
+      const unsigned char *z0;
+      unsigned char c;
+      if( z==0 ) return;
+      z0 = z;
+      while( (c = *z)!=0 ){
+        z++;
+        if( c>=0xc0 ){
+          while( (*z & 0xc0)==0x80 ){ z++; z0++; }
+        }
+      }
+      sqlite3_result_int(context, (int)(z-z0));
+      break;
+    }
+    default: {
+      sqlite3_result_null(context);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the octet_length() function
+*/
+static void bytelengthFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_BLOB: {
+      sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
+      break;
+    }
+    case SQLITE_INTEGER:
+    case SQLITE_FLOAT: {
+      i64 m = sqlite3_context_db_handle(context)->enc<=SQLITE_UTF8 ? 1 : 2;
+      sqlite3_result_int64(context, sqlite3_value_bytes(argv[0])*m);
+      break;
+    }
+    case SQLITE_TEXT: {
+      if( sqlite3_value_encoding(argv[0])<=SQLITE_UTF8 ){
+        sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
+      }else{
+        sqlite3_result_int(context, sqlite3_value_bytes16(argv[0]));
+      }
+      break;
+    }
+    default: {
+      sqlite3_result_null(context);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the abs() function.
+**
+** IMP: R-23979-26855 The abs(X) function returns the absolute value of
+** the numeric argument X.
+*/
+static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_INTEGER: {
+      i64 iVal = sqlite3_value_int64(argv[0]);
+      if( iVal<0 ){
+        if( iVal==SMALLEST_INT64 ){
+          /* IMP: R-31676-45509 If X is the integer -9223372036854775808
+          ** then abs(X) throws an integer overflow error since there is no
+          ** equivalent positive 64-bit two complement value. */
+          sqlite3_result_error(context, "integer overflow", -1);
+          return;
+        }
+        iVal = -iVal;
+      }
+      sqlite3_result_int64(context, iVal);
+      break;
+    }
+    case SQLITE_NULL: {
+      /* IMP: R-37434-19929 Abs(X) returns NULL if X is NULL. */
+      sqlite3_result_null(context);
+      break;
+    }
+    default: {
+      /* Because sqlite3_value_double() returns 0.0 if the argument is not
+      ** something that can be converted into a number, we have:
+      ** IMP: R-01992-00519 Abs(X) returns 0.0 if X is a string or blob
+      ** that cannot be converted to a numeric value.
+      */
+      double rVal = sqlite3_value_double(argv[0]);
+      if( rVal<0 ) rVal = -rVal;
+      sqlite3_result_double(context, rVal);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the instr() function.
+**
+** instr(haystack,needle) finds the first occurrence of needle
+** in haystack and returns the number of previous characters plus 1,
+** or 0 if needle does not occur within haystack.
+**
+** If both haystack and needle are BLOBs, then the result is one more than
+** the number of bytes in haystack prior to the first occurrence of needle,
+** or 0 if needle never occurs in haystack.
+*/
+static void instrFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zHaystack;
+  const unsigned char *zNeedle;
+  int nHaystack;
+  int nNeedle;
+  int typeHaystack, typeNeedle;
+  int N = 1;
+  int isText;
+  unsigned char firstChar;
+  sqlite3_value *pC1 = 0;
+  sqlite3_value *pC2 = 0;
+
+  UNUSED_PARAMETER(argc);
+  typeHaystack = sqlite3_value_type(argv[0]);
+  typeNeedle = sqlite3_value_type(argv[1]);
+  if( typeHaystack==SQLITE_NULL || typeNeedle==SQLITE_NULL ) return;
+  nHaystack = sqlite3_value_bytes(argv[0]);
+  nNeedle = sqlite3_value_bytes(argv[1]);
+  if( nNeedle>0 ){
+    if( typeHaystack==SQLITE_BLOB && typeNeedle==SQLITE_BLOB ){
+      zHaystack = sqlite3_value_blob(argv[0]);
+      zNeedle = sqlite3_value_blob(argv[1]);
+      isText = 0;
+    }else if( typeHaystack!=SQLITE_BLOB && typeNeedle!=SQLITE_BLOB ){
+      zHaystack = sqlite3_value_text(argv[0]);
+      zNeedle = sqlite3_value_text(argv[1]);
+      isText = 1;
+    }else{
+      pC1 = sqlite3_value_dup(argv[0]);
+      zHaystack = sqlite3_value_text(pC1);
+      if( zHaystack==0 ) goto endInstrOOM;
+      nHaystack = sqlite3_value_bytes(pC1);
+      pC2 = sqlite3_value_dup(argv[1]);
+      zNeedle = sqlite3_value_text(pC2);
+      if( zNeedle==0 ) goto endInstrOOM;
+      nNeedle = sqlite3_value_bytes(pC2);
+      isText = 1;
+    }
+    if( zNeedle==0 || (nHaystack && zHaystack==0) ) goto endInstrOOM;
+    firstChar = zNeedle[0];
+    while( nNeedle<=nHaystack
+       && (zHaystack[0]!=firstChar || memcmp(zHaystack, zNeedle, nNeedle)!=0)
+    ){
+      N++;
+      do{
+        nHaystack--;
+        zHaystack++;
+      }while( isText && (zHaystack[0]&0xc0)==0x80 );
+    }
+    if( nNeedle>nHaystack ) N = 0;
+  }
+  sqlite3_result_int(context, N);
+endInstr:
+  sqlite3_value_free(pC1);
+  sqlite3_value_free(pC2);
+  return;
+endInstrOOM:
+  sqlite3_result_error_nomem(context);
+  goto endInstr;
+}
+
+/*
+** Implementation of the printf() (a.k.a. format()) SQL function.
+*/
+static void printfFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  PrintfArguments x;
+  StrAccum str;
+  const char *zFormat;
+  int n;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+
+  if( argc>=1 && (zFormat = (const char*)sqlite3_value_text(argv[0]))!=0 ){
+    x.nArg = argc-1;
+    x.nUsed = 0;
+    x.apArg = argv+1;
+    sqlite3StrAccumInit(&str, db, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
+    str.printfFlags = SQLITE_PRINTF_SQLFUNC;
+    sqlite3_str_appendf(&str, zFormat, &x);
+    n = str.nChar;
+    sqlite3_result_text(context, sqlite3StrAccumFinish(&str), n,
+                        SQLITE_DYNAMIC);
+  }
+}
+
+/*
+** Implementation of the substr() function.
+**
+** substr(x,p1,p2)  returns p2 characters of x[] beginning with p1.
+** p1 is 1-indexed.  So substr(x,1,1) returns the first character
+** of x.  If x is text, then we actually count UTF-8 characters.
+** If x is a blob, then we count bytes.
+**
+** If p1 is negative, then we begin abs(p1) from the end of x[].
+**
+** If p2 is negative, return the p2 characters preceding p1.
+*/
+static void substrFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *z;
+  const unsigned char *z2;
+  int len;
+  int p0type;
+  i64 p1, p2;
+
+  assert( argc==3 || argc==2 );
+  if( sqlite3_value_type(argv[1])==SQLITE_NULL
+   || (argc==3 && sqlite3_value_type(argv[2])==SQLITE_NULL)
+  ){
+    return;
+  }
+  p0type = sqlite3_value_type(argv[0]);
+  p1 = sqlite3_value_int64(argv[1]);
+  if( p0type==SQLITE_BLOB ){
+    len = sqlite3_value_bytes(argv[0]);
+    z = sqlite3_value_blob(argv[0]);
+    if( z==0 ) return;
+    assert( len==sqlite3_value_bytes(argv[0]) );
+  }else{
+    z = sqlite3_value_text(argv[0]);
+    if( z==0 ) return;
+    len = 0;
+    if( p1<0 ){
+      for(z2=z; *z2; len++){
+        SQLITE_SKIP_UTF8(z2);
+      }
+    }
+  }
+#ifdef SQLITE_SUBSTR_COMPATIBILITY
+  /* If SUBSTR_COMPATIBILITY is defined then substr(X,0,N) work the same as
+  ** as substr(X,1,N) - it returns the first N characters of X.  This
+  ** is essentially a back-out of the bug-fix in check-in [5fc125d362df4b8]
+  ** from 2009-02-02 for compatibility of applications that exploited the
+  ** old buggy behavior. */
+  if( p1==0 ) p1 = 1; /* <rdar://problem/6778339> */
+#endif
+  if( argc==3 ){
+    p2 = sqlite3_value_int64(argv[2]);
+  }else{
+    p2 = sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH];
+  }
+  if( p1<0 ){
+    p1 += len;
+    if( p1<0 ){
+      if( p2<0 ){
+        p2 = 0;
+      }else{
+        p2 += p1;
+      }
+      p1 = 0;
+    }
+  }else if( p1>0 ){
+    p1--;
+  }else if( p2>0 ){
+    p2--;
+  }
+  if( p2<0 ){
+    if( p2<-p1 ){
+      p2 = p1;
+    }else{
+      p2 = -p2;
+    }
+    p1 -= p2;
+  }
+  assert( p1>=0 && p2>=0 );
+  if( p0type!=SQLITE_BLOB ){
+    while( *z && p1 ){
+      SQLITE_SKIP_UTF8(z);
+      p1--;
+    }
+    for(z2=z; *z2 && p2; p2--){
+      SQLITE_SKIP_UTF8(z2);
+    }
+    sqlite3_result_text64(context, (char*)z, z2-z, SQLITE_TRANSIENT,
+                          SQLITE_UTF8);
+  }else{
+    if( p1>=len ){
+      p1 = p2 = 0;
+    }else if( p2>len-p1 ){
+      p2 = len-p1;
+      assert( p2>0 );
+    }
+    sqlite3_result_blob64(context, (char*)&z[p1], (u64)p2, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+** Implementation of the round() function
+*/
+#ifndef SQLITE_OMIT_FLOATING_POINT
+static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  i64 n = 0;
+  double r;
+  char *zBuf;
+  assert( argc==1 || argc==2 );
+  if( argc==2 ){
+    if( SQLITE_NULL==sqlite3_value_type(argv[1]) ) return;
+    n = sqlite3_value_int64(argv[1]);
+    if( n>30 ) n = 30;
+    if( n<0 ) n = 0;
+  }
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  r = sqlite3_value_double(argv[0]);
+  /* If Y==0 and X will fit in a 64-bit int,
+  ** handle the rounding directly,
+  ** otherwise use printf.
+  */
+  if( r<-4503599627370496.0 || r>+4503599627370496.0 ){
+    /* The value has no fractional part so there is nothing to round */
+  }else if( n==0 ){
+    r = (double)((sqlite_int64)(r+(r<0?-0.5:+0.5)));
+  }else{
+    zBuf = sqlite3_mprintf("%!.*f",(int)n,r);
+    if( zBuf==0 ){
+      sqlite3_result_error_nomem(context);
+      return;
+    }
+    sqlite3AtoF(zBuf, &r, sqlite3Strlen30(zBuf), SQLITE_UTF8);
+    sqlite3_free(zBuf);
+  }
+  sqlite3_result_double(context, r);
+}
+#endif
+
+/*
+** Allocate nByte bytes of space using sqlite3Malloc(). If the
+** allocation fails, call sqlite3_result_error_nomem() to notify
+** the database handle that malloc() has failed and return NULL.
+** If nByte is larger than the maximum string or blob length, then
+** raise an SQLITE_TOOBIG exception and return NULL.
+*/
+static void *contextMalloc(sqlite3_context *context, i64 nByte){
+  char *z;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  assert( nByte>0 );
+  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH] );
+  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH]+1 );
+  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    sqlite3_result_error_toobig(context);
+    z = 0;
+  }else{
+    z = sqlite3Malloc(nByte);
+    if( !z ){
+      sqlite3_result_error_nomem(context);
+    }
+  }
+  return z;
+}
+
+/*
+** Implementation of the upper() and lower() SQL functions.
+*/
+static void upperFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  char *z1;
+  const char *z2;
+  int i, n;
+  UNUSED_PARAMETER(argc);
+  z2 = (char*)sqlite3_value_text(argv[0]);
+  n = sqlite3_value_bytes(argv[0]);
+  /* Verify that the call to _bytes() does not invalidate the _text() pointer */
+  assert( z2==(char*)sqlite3_value_text(argv[0]) );
+  if( z2 ){
+    z1 = contextMalloc(context, ((i64)n)+1);
+    if( z1 ){
+      for(i=0; i<n; i++){
+        z1[i] = (char)sqlite3Toupper(z2[i]);
+      }
+      sqlite3_result_text(context, z1, n, sqlite3_free);
+    }
+  }
+}
+static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  char *z1;
+  const char *z2;
+  int i, n;
+  UNUSED_PARAMETER(argc);
+  z2 = (char*)sqlite3_value_text(argv[0]);
+  n = sqlite3_value_bytes(argv[0]);
+  /* Verify that the call to _bytes() does not invalidate the _text() pointer */
+  assert( z2==(char*)sqlite3_value_text(argv[0]) );
+  if( z2 ){
+    z1 = contextMalloc(context, ((i64)n)+1);
+    if( z1 ){
+      for(i=0; i<n; i++){
+        z1[i] = sqlite3Tolower(z2[i]);
+      }
+      sqlite3_result_text(context, z1, n, sqlite3_free);
+    }
+  }
+}
+
+/*
+** Some functions like COALESCE() and IFNULL() and UNLIKELY() are implemented
+** as VDBE code so that unused argument values do not have to be computed.
+** However, we still need some kind of function implementation for this
+** routines in the function table.  The noopFunc macro provides this.
+** noopFunc will never be called so it doesn't matter what the implementation
+** is.  We might as well use the "version()" function as a substitute.
+*/
+#define noopFunc versionFunc   /* Substitute function - never called */
+
+/*
+** Implementation of random().  Return a random integer.
+*/
+static void randomFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  sqlite_int64 r;
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  sqlite3_randomness(sizeof(r), &r);
+  if( r<0 ){
+    /* We need to prevent a random number of 0x8000000000000000
+    ** (or -9223372036854775808) since when you do abs() of that
+    ** number of you get the same value back again.  To do this
+    ** in a way that is testable, mask the sign bit off of negative
+    ** values, resulting in a positive value.  Then take the
+    ** 2s complement of that positive value.  The end result can
+    ** therefore be no less than -9223372036854775807.
+    */
+    r = -(r & LARGEST_INT64);
+  }
+  sqlite3_result_int64(context, r);
+}
+
+/*
+** Implementation of randomblob(N).  Return a random blob
+** that is N bytes long.
+*/
+static void randomBlob(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_int64 n;
+  unsigned char *p;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  n = sqlite3_value_int64(argv[0]);
+  if( n<1 ){
+    n = 1;
+  }
+  p = contextMalloc(context, n);
+  if( p ){
+    sqlite3_randomness(n, p);
+    sqlite3_result_blob(context, (char*)p, n, sqlite3_free);
+  }
+}
+
+/*
+** Implementation of the last_insert_rowid() SQL function.  The return
+** value is the same as the sqlite3_last_insert_rowid() API function.
+*/
+static void last_insert_rowid(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-51513-12026 The last_insert_rowid() SQL function is a
+  ** wrapper around the sqlite3_last_insert_rowid() C/C++ interface
+  ** function. */
+  sqlite3_result_int64(context, sqlite3_last_insert_rowid(db));
+}
+
+/*
+** Implementation of the changes() SQL function.
+**
+** IMP: R-32760-32347 The changes() SQL function is a wrapper
+** around the sqlite3_changes64() C/C++ function and hence follows the
+** same rules for counting changes.
+*/
+static void changes(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  sqlite3_result_int64(context, sqlite3_changes64(db));
+}
+
+/*
+** Implementation of the total_changes() SQL function.  The return value is
+** the same as the sqlite3_total_changes64() API function.
+*/
+static void total_changes(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-11217-42568 This function is a wrapper around the
+  ** sqlite3_total_changes64() C/C++ interface. */
+  sqlite3_result_int64(context, sqlite3_total_changes64(db));
+}
+
+/*
+** A structure defining how to do GLOB-style comparisons.
+*/
+struct compareInfo {
+  u8 matchAll;          /* "*" or "%" */
+  u8 matchOne;          /* "?" or "_" */
+  u8 matchSet;          /* "[" or 0 */
+  u8 noCase;            /* true to ignore case differences */
+};
+
+/*
+** For LIKE and GLOB matching on EBCDIC machines, assume that every
+** character is exactly one byte in size.  Also, provide the Utf8Read()
+** macro for fast reading of the next character in the common case where
+** the next character is ASCII.
+*/
+#if defined(SQLITE_EBCDIC)
+# define sqlite3Utf8Read(A)        (*((*A)++))
+# define Utf8Read(A)               (*(A++))
+#else
+# define Utf8Read(A)               (A[0]<0x80?*(A++):sqlite3Utf8Read(&A))
+#endif
+
+static const struct compareInfo globInfo = { '*', '?', '[', 0 };
+/* The correct SQL-92 behavior is for the LIKE operator to ignore
+** case.  Thus  'a' LIKE 'A' would be true. */
+static const struct compareInfo likeInfoNorm = { '%', '_',   0, 1 };
+/* If SQLITE_CASE_SENSITIVE_LIKE is defined, then the LIKE operator
+** is case sensitive causing 'a' LIKE 'A' to be false */
+static const struct compareInfo likeInfoAlt = { '%', '_',   0, 0 };
+
+/*
+** Possible error returns from patternMatch()
+*/
+#define SQLITE_MATCH             0
+#define SQLITE_NOMATCH           1
+#define SQLITE_NOWILDCARDMATCH   2
+
+/*
+** Compare two UTF-8 strings for equality where the first string is
+** a GLOB or LIKE expression.  Return values:
+**
+**    SQLITE_MATCH:            Match
+**    SQLITE_NOMATCH:          No match
+**    SQLITE_NOWILDCARDMATCH:  No match in spite of having * or % wildcards.
+**
+** Globbing rules:
+**
+**      '*'       Matches any sequence of zero or more characters.
+**
+**      '?'       Matches exactly one character.
+**
+**     [...]      Matches one character from the enclosed list of
+**                characters.
+**
+**     [^...]     Matches one character not in the enclosed list.
+**
+** With the [...] and [^...] matching, a ']' character can be included
+** in the list by making it the first character after '[' or '^'.  A
+** range of characters can be specified using '-'.  Example:
+** "[a-z]" matches any single lower-case letter.  To match a '-', make
+** it the last character in the list.
+**
+** Like matching rules:
+**
+**      '%'       Matches any sequence of zero or more characters
+**
+***     '_'       Matches any one character
+**
+**      Ec        Where E is the "esc" character and c is any other
+**                character, including '%', '_', and esc, match exactly c.
+**
+** The comments within this routine usually assume glob matching.
+**
+** This routine is usually quick, but can be N**2 in the worst case.
+*/
+static int patternCompare(
+  const u8 *zPattern,              /* The glob pattern */
+  const u8 *zString,               /* The string to compare against the glob */
+  const struct compareInfo *pInfo, /* Information about how to do the compare */
+  u32 matchOther                   /* The escape char (LIKE) or '[' (GLOB) */
+){
+  u32 c, c2;                       /* Next pattern and input string chars */
+  u32 matchOne = pInfo->matchOne;  /* "?" or "_" */
+  u32 matchAll = pInfo->matchAll;  /* "*" or "%" */
+  u8 noCase = pInfo->noCase;       /* True if uppercase==lowercase */
+  const u8 *zEscaped = 0;          /* One past the last escaped input char */
+
+  while( (c = Utf8Read(zPattern))!=0 ){
+    if( c==matchAll ){  /* Match "*" */
+      /* Skip over multiple "*" characters in the pattern.  If there
+      ** are also "?" characters, skip those as well, but consume a
+      ** single character of the input string for each "?" skipped */
+      while( (c=Utf8Read(zPattern)) == matchAll
+             || (c == matchOne && matchOne!=0) ){
+        if( c==matchOne && sqlite3Utf8Read(&zString)==0 ){
+          return SQLITE_NOWILDCARDMATCH;
+        }
+      }
+      if( c==0 ){
+        return SQLITE_MATCH;   /* "*" at the end of the pattern matches */
+      }else if( c==matchOther ){
+        if( pInfo->matchSet==0 ){
+          c = sqlite3Utf8Read(&zPattern);
+          if( c==0 ) return SQLITE_NOWILDCARDMATCH;
+        }else{
+          /* "[...]" immediately follows the "*".  We have to do a slow
+          ** recursive search in this case, but it is an unusual case. */
+          assert( matchOther<0x80 );  /* '[' is a single-byte character */
+          while( *zString ){
+            int bMatch = patternCompare(&zPattern[-1],zString,pInfo,matchOther);
+            if( bMatch!=SQLITE_NOMATCH ) return bMatch;
+            SQLITE_SKIP_UTF8(zString);
+          }
+          return SQLITE_NOWILDCARDMATCH;
+        }
+      }
+
+      /* At this point variable c contains the first character of the
+      ** pattern string past the "*".  Search in the input string for the
+      ** first matching character and recursively continue the match from
+      ** that point.
+      **
+      ** For a case-insensitive search, set variable cx to be the same as
+      ** c but in the other case and search the input string for either
+      ** c or cx.
+      */
+      if( c<0x80 ){
+        char zStop[3];
+        int bMatch;
+        if( noCase ){
+          zStop[0] = sqlite3Toupper(c);
+          zStop[1] = sqlite3Tolower(c);
+          zStop[2] = 0;
+        }else{
+          zStop[0] = c;
+          zStop[1] = 0;
+        }
+        while(1){
+          zString += strcspn((const char*)zString, zStop);
+          if( zString[0]==0 ) break;
+          zString++;
+          bMatch = patternCompare(zPattern,zString,pInfo,matchOther);
+          if( bMatch!=SQLITE_NOMATCH ) return bMatch;
+        }
+      }else{
+        int bMatch;
+        while( (c2 = Utf8Read(zString))!=0 ){
+          if( c2!=c ) continue;
+          bMatch = patternCompare(zPattern,zString,pInfo,matchOther);
+          if( bMatch!=SQLITE_NOMATCH ) return bMatch;
+        }
+      }
+      return SQLITE_NOWILDCARDMATCH;
+    }
+    if( c==matchOther ){
+      if( pInfo->matchSet==0 ){
+        c = sqlite3Utf8Read(&zPattern);
+        if( c==0 ) return SQLITE_NOMATCH;
+        zEscaped = zPattern;
+      }else{
+        u32 prior_c = 0;
+        int seen = 0;
+        int invert = 0;
+        c = sqlite3Utf8Read(&zString);
+        if( c==0 ) return SQLITE_NOMATCH;
+        c2 = sqlite3Utf8Read(&zPattern);
+        if( c2=='^' ){
+          invert = 1;
+          c2 = sqlite3Utf8Read(&zPattern);
+        }
+        if( c2==']' ){
+          if( c==']' ) seen = 1;
+          c2 = sqlite3Utf8Read(&zPattern);
+        }
+        while( c2 && c2!=']' ){
+          if( c2=='-' && zPattern[0]!=']' && zPattern[0]!=0 && prior_c>0 ){
+            c2 = sqlite3Utf8Read(&zPattern);
+            if( c>=prior_c && c<=c2 ) seen = 1;
+            prior_c = 0;
+          }else{
+            if( c==c2 ){
+              seen = 1;
+            }
+            prior_c = c2;
+          }
+          c2 = sqlite3Utf8Read(&zPattern);
+        }
+        if( c2==0 || (seen ^ invert)==0 ){
+          return SQLITE_NOMATCH;
+        }
+        continue;
+      }
+    }
+    c2 = Utf8Read(zString);
+    if( c==c2 ) continue;
+    if( noCase  && sqlite3Tolower(c)==sqlite3Tolower(c2) && c<0x80 && c2<0x80 ){
+      continue;
+    }
+    if( c==matchOne && zPattern!=zEscaped && c2!=0 ) continue;
+    return SQLITE_NOMATCH;
+  }
+  return *zString==0 ? SQLITE_MATCH : SQLITE_NOMATCH;
+}
+
+/*
+** The sqlite3_strglob() interface.  Return 0 on a match (like strcmp()) and
+** non-zero if there is no match.
+*/
+SQLITE_API int sqlite3_strglob(const char *zGlobPattern, const char *zString){
+  if( zString==0 ){
+    return zGlobPattern!=0;
+  }else if( zGlobPattern==0 ){
+    return 1;
+  }else {
+    return patternCompare((u8*)zGlobPattern, (u8*)zString, &globInfo, '[');
+  }
+}
+
+/*
+** The sqlite3_strlike() interface.  Return 0 on a match and non-zero for
+** a miss - like strcmp().
+*/
+SQLITE_API int sqlite3_strlike(const char *zPattern, const char *zStr, unsigned int esc){
+  if( zStr==0 ){
+    return zPattern!=0;
+  }else if( zPattern==0 ){
+    return 1;
+  }else{
+    return patternCompare((u8*)zPattern, (u8*)zStr, &likeInfoNorm, esc);
+  }
+}
+
+/*
+** Count the number of times that the LIKE operator (or GLOB which is
+** just a variation of LIKE) gets called.  This is used for testing
+** only.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_like_count = 0;
+#endif
+
+
+/*
+** Implementation of the like() SQL function.  This function implements
+** the built-in LIKE operator.  The first argument to the function is the
+** pattern and the second argument is the string.  So, the SQL statements:
+**
+**       A LIKE B
+**
+** is implemented as like(B,A).
+**
+** This same function (with a different compareInfo structure) computes
+** the GLOB operator.
+*/
+static void likeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zA, *zB;
+  u32 escape;
+  int nPat;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  struct compareInfo *pInfo = sqlite3_user_data(context);
+  struct compareInfo backupInfo;
+
+#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+  if( sqlite3_value_type(argv[0])==SQLITE_BLOB
+   || sqlite3_value_type(argv[1])==SQLITE_BLOB
+  ){
+#ifdef SQLITE_TEST
+    sqlite3_like_count++;
+#endif
+    sqlite3_result_int(context, 0);
+    return;
+  }
+#endif
+
+  /* Limit the length of the LIKE or GLOB pattern to avoid problems
+  ** of deep recursion and N*N behavior in patternCompare().
+  */
+  nPat = sqlite3_value_bytes(argv[0]);
+  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] );
+  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]+1 );
+  if( nPat > db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] ){
+    sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
+    return;
+  }
+  if( argc==3 ){
+    /* The escape character string must consist of a single UTF-8 character.
+    ** Otherwise, return an error.
+    */
+    const unsigned char *zEsc = sqlite3_value_text(argv[2]);
+    if( zEsc==0 ) return;
+    if( sqlite3Utf8CharLen((char*)zEsc, -1)!=1 ){
+      sqlite3_result_error(context,
+          "ESCAPE expression must be a single character", -1);
+      return;
+    }
+    escape = sqlite3Utf8Read(&zEsc);
+    if( escape==pInfo->matchAll || escape==pInfo->matchOne ){
+      memcpy(&backupInfo, pInfo, sizeof(backupInfo));
+      pInfo = &backupInfo;
+      if( escape==pInfo->matchAll ) pInfo->matchAll = 0;
+      if( escape==pInfo->matchOne ) pInfo->matchOne = 0;
+    }
+  }else{
+    escape = pInfo->matchSet;
+  }
+  zB = sqlite3_value_text(argv[0]);
+  zA = sqlite3_value_text(argv[1]);
+  if( zA && zB ){
+#ifdef SQLITE_TEST
+    sqlite3_like_count++;
+#endif
+    sqlite3_result_int(context,
+                      patternCompare(zB, zA, pInfo, escape)==SQLITE_MATCH);
+  }
+}
+
+/*
+** Implementation of the NULLIF(x,y) function.  The result is the first
+** argument if the arguments are different.  The result is NULL if the
+** arguments are equal to each other.
+*/
+static void nullifFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  CollSeq *pColl = sqlite3GetFuncCollSeq(context);
+  UNUSED_PARAMETER(NotUsed);
+  if( sqlite3MemCompare(argv[0], argv[1], pColl)!=0 ){
+    sqlite3_result_value(context, argv[0]);
+  }
+}
+
+/*
+** Implementation of the sqlite_version() function.  The result is the version
+** of the SQLite library that is running.
+*/
+static void versionFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-48699-48617 This function is an SQL wrapper around the
+  ** sqlite3_libversion() C-interface. */
+  sqlite3_result_text(context, sqlite3_libversion(), -1, SQLITE_STATIC);
+}
+
+/*
+** Implementation of the sqlite_source_id() function. The result is a string
+** that identifies the particular version of the source code used to build
+** SQLite.
+*/
+static void sourceidFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-24470-31136 This function is an SQL wrapper around the
+  ** sqlite3_sourceid() C interface. */
+  sqlite3_result_text(context, sqlite3_sourceid(), -1, SQLITE_STATIC);
+}
+
+/*
+** Implementation of the sqlite_log() function.  This is a wrapper around
+** sqlite3_log().  The return value is NULL.  The function exists purely for
+** its side-effects.
+*/
+static void errlogFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(context);
+  sqlite3_log(sqlite3_value_int(argv[0]), "%s", sqlite3_value_text(argv[1]));
+}
+
+/*
+** Implementation of the sqlite_compileoption_used() function.
+** The result is an integer that identifies if the compiler option
+** was used to build SQLite.
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+static void compileoptionusedFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *zOptName;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  /* IMP: R-39564-36305 The sqlite_compileoption_used() SQL
+  ** function is a wrapper around the sqlite3_compileoption_used() C/C++
+  ** function.
+  */
+  if( (zOptName = (const char*)sqlite3_value_text(argv[0]))!=0 ){
+    sqlite3_result_int(context, sqlite3_compileoption_used(zOptName));
+  }
+}
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/*
+** Implementation of the sqlite_compileoption_get() function.
+** The result is a string that identifies the compiler options
+** used to build SQLite.
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+static void compileoptiongetFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int n;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  /* IMP: R-04922-24076 The sqlite_compileoption_get() SQL function
+  ** is a wrapper around the sqlite3_compileoption_get() C/C++ function.
+  */
+  n = sqlite3_value_int(argv[0]);
+  sqlite3_result_text(context, sqlite3_compileoption_get(n), -1, SQLITE_STATIC);
+}
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/* Array for converting from half-bytes (nybbles) into ASCII hex
+** digits. */
+static const char hexdigits[] = {
+  '0', '1', '2', '3', '4', '5', '6', '7',
+  '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+};
+
+/*
+** Append to pStr text that is the SQL literal representation of the
+** value contained in pValue.
+*/
+SQLITE_PRIVATE void sqlite3QuoteValue(StrAccum *pStr, sqlite3_value *pValue){
+  /* As currently implemented, the string must be initially empty.
+  ** we might relax this requirement in the future, but that will
+  ** require enhancements to the implementation. */
+  assert( pStr!=0 && pStr->nChar==0 );
+
+  switch( sqlite3_value_type(pValue) ){
+    case SQLITE_FLOAT: {
+      double r1, r2;
+      const char *zVal;
+      r1 = sqlite3_value_double(pValue);
+      sqlite3_str_appendf(pStr, "%!0.15g", r1);
+      zVal = sqlite3_str_value(pStr);
+      if( zVal ){
+        sqlite3AtoF(zVal, &r2, pStr->nChar, SQLITE_UTF8);
+        if( r1!=r2 ){
+          sqlite3_str_reset(pStr);
+          sqlite3_str_appendf(pStr, "%!0.20e", r1);
+        }
+      }
+      break;
+    }
+    case SQLITE_INTEGER: {
+      sqlite3_str_appendf(pStr, "%lld", sqlite3_value_int64(pValue));
+      break;
+    }
+    case SQLITE_BLOB: {
+      char const *zBlob = sqlite3_value_blob(pValue);
+      i64 nBlob = sqlite3_value_bytes(pValue);
+      assert( zBlob==sqlite3_value_blob(pValue) ); /* No encoding change */
+      sqlite3StrAccumEnlarge(pStr, nBlob*2 + 4);
+      if( pStr->accError==0 ){
+        char *zText = pStr->zText;
+        int i;
+        for(i=0; i<nBlob; i++){
+          zText[(i*2)+2] = hexdigits[(zBlob[i]>>4)&0x0F];
+          zText[(i*2)+3] = hexdigits[(zBlob[i])&0x0F];
+        }
+        zText[(nBlob*2)+2] = '\'';
+        zText[(nBlob*2)+3] = '\0';
+        zText[0] = 'X';
+        zText[1] = '\'';
+        pStr->nChar = nBlob*2 + 3;
+      }
+      break;
+    }
+    case SQLITE_TEXT: {
+      const unsigned char *zArg = sqlite3_value_text(pValue);
+      sqlite3_str_appendf(pStr, "%Q", zArg);
+      break;
+    }
+    default: {
+      assert( sqlite3_value_type(pValue)==SQLITE_NULL );
+      sqlite3_str_append(pStr, "NULL", 4);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the QUOTE() function.
+**
+** The quote(X) function returns the text of an SQL literal which is the
+** value of its argument suitable for inclusion into an SQL statement.
+** Strings are surrounded by single-quotes with escapes on interior quotes
+** as needed. BLOBs are encoded as hexadecimal literals. Strings with
+** embedded NUL characters cannot be represented as string literals in SQL
+** and hence the returned string literal is truncated prior to the first NUL.
+*/
+static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  sqlite3_str str;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  sqlite3StrAccumInit(&str, db, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
+  sqlite3QuoteValue(&str,argv[0]);
+  sqlite3_result_text(context, sqlite3StrAccumFinish(&str), str.nChar,
+                      SQLITE_DYNAMIC);
+  if( str.accError!=SQLITE_OK ){
+    sqlite3_result_null(context);
+    sqlite3_result_error_code(context, str.accError);
+  }
+}
+
+/*
+** The unicode() function.  Return the integer unicode code-point value
+** for the first character of the input string.
+*/
+static void unicodeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *z = sqlite3_value_text(argv[0]);
+  (void)argc;
+  if( z && z[0] ) sqlite3_result_int(context, sqlite3Utf8Read(&z));
+}
+
+/*
+** The char() function takes zero or more arguments, each of which is
+** an integer.  It constructs a string where each character of the string
+** is the unicode character for the corresponding integer argument.
+*/
+static void charFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  unsigned char *z, *zOut;
+  int i;
+  zOut = z = sqlite3_malloc64( argc*4+1 );
+  if( z==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+  for(i=0; i<argc; i++){
+    sqlite3_int64 x;
+    unsigned c;
+    x = sqlite3_value_int64(argv[i]);
+    if( x<0 || x>0x10ffff ) x = 0xfffd;
+    c = (unsigned)(x & 0x1fffff);
+    if( c<0x00080 ){
+      *zOut++ = (u8)(c&0xFF);
+    }else if( c<0x00800 ){
+      *zOut++ = 0xC0 + (u8)((c>>6)&0x1F);
+      *zOut++ = 0x80 + (u8)(c & 0x3F);
+    }else if( c<0x10000 ){
+      *zOut++ = 0xE0 + (u8)((c>>12)&0x0F);
+      *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);
+      *zOut++ = 0x80 + (u8)(c & 0x3F);
+    }else{
+      *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);
+      *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);
+      *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);
+      *zOut++ = 0x80 + (u8)(c & 0x3F);
+    }                                                    \
+  }
+  *zOut = 0;
+  sqlite3_result_text64(context, (char*)z, zOut-z, sqlite3_free, SQLITE_UTF8);
+}
+
+/*
+** The hex() function.  Interpret the argument as a blob.  Return
+** a hexadecimal rendering as text.
+*/
+static void hexFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i, n;
+  const unsigned char *pBlob;
+  char *zHex, *z;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  pBlob = sqlite3_value_blob(argv[0]);
+  n = sqlite3_value_bytes(argv[0]);
+  assert( pBlob==sqlite3_value_blob(argv[0]) );  /* No encoding change */
+  z = zHex = contextMalloc(context, ((i64)n)*2 + 1);
+  if( zHex ){
+    for(i=0; i<n; i++, pBlob++){
+      unsigned char c = *pBlob;
+      *(z++) = hexdigits[(c>>4)&0xf];
+      *(z++) = hexdigits[c&0xf];
+    }
+    *z = 0;
+    sqlite3_result_text64(context, zHex, (u64)(z-zHex),
+                          sqlite3_free, SQLITE_UTF8);
+  }
+}
+
+/*
+** Buffer zStr contains nStr bytes of utf-8 encoded text. Return 1 if zStr
+** contains character ch, or 0 if it does not.
+*/
+static int strContainsChar(const u8 *zStr, int nStr, u32 ch){
+  const u8 *zEnd = &zStr[nStr];
+  const u8 *z = zStr;
+  while( z<zEnd ){
+    u32 tst = Utf8Read(z);
+    if( tst==ch ) return 1;
+  }
+  return 0;
+}
+
+/*
+** The unhex() function. This function may be invoked with either one or
+** two arguments. In both cases the first argument is interpreted as text
+** a text value containing a set of pairs of hexadecimal digits which are
+** decoded and returned as a blob.
+**
+** If there is only a single argument, then it must consist only of an
+** even number of hexadecimal digits. Otherwise, return NULL.
+**
+** Or, if there is a second argument, then any character that appears in
+** the second argument is also allowed to appear between pairs of hexadecimal
+** digits in the first argument. If any other character appears in the
+** first argument, or if one of the allowed characters appears between
+** two hexadecimal digits that make up a single byte, NULL is returned.
+**
+** The following expressions are all true:
+**
+**     unhex('ABCD')       IS x'ABCD'
+**     unhex('AB CD')      IS NULL
+**     unhex('AB CD', ' ') IS x'ABCD'
+**     unhex('A BCD', ' ') IS NULL
+*/
+static void unhexFunc(
+  sqlite3_context *pCtx,
+  int argc,
+  sqlite3_value **argv
+){
+  const u8 *zPass = (const u8*)"";
+  int nPass = 0;
+  const u8 *zHex = sqlite3_value_text(argv[0]);
+  int nHex = sqlite3_value_bytes(argv[0]);
+#ifdef SQLITE_DEBUG
+  const u8 *zEnd = zHex ? &zHex[nHex] : 0;
+#endif
+  u8 *pBlob = 0;
+  u8 *p = 0;
+
+  assert( argc==1 || argc==2 );
+  if( argc==2 ){
+    zPass = sqlite3_value_text(argv[1]);
+    nPass = sqlite3_value_bytes(argv[1]);
+  }
+  if( !zHex || !zPass ) return;
+
+  p = pBlob = contextMalloc(pCtx, (nHex/2)+1);
+  if( pBlob ){
+    u8 c;                         /* Most significant digit of next byte */
+    u8 d;                         /* Least significant digit of next byte */
+
+    while( (c = *zHex)!=0x00 ){
+      while( !sqlite3Isxdigit(c) ){
+        u32 ch = Utf8Read(zHex);
+        assert( zHex<=zEnd );
+        if( !strContainsChar(zPass, nPass, ch) ) goto unhex_null;
+        c = *zHex;
+        if( c==0x00 ) goto unhex_done;
+      }
+      zHex++;
+      assert( *zEnd==0x00 );
+      assert( zHex<=zEnd );
+      d = *(zHex++);
+      if( !sqlite3Isxdigit(d) ) goto unhex_null;
+      *(p++) = (sqlite3HexToInt(c)<<4) | sqlite3HexToInt(d);
+    }
+  }
+
+ unhex_done:
+  sqlite3_result_blob(pCtx, pBlob, (p - pBlob), sqlite3_free);
+  return;
+
+ unhex_null:
+  sqlite3_free(pBlob);
+  return;
+}
+
+
+/*
+** The zeroblob(N) function returns a zero-filled blob of size N bytes.
+*/
+static void zeroblobFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  i64 n;
+  int rc;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  n = sqlite3_value_int64(argv[0]);
+  if( n<0 ) n = 0;
+  rc = sqlite3_result_zeroblob64(context, n); /* IMP: R-00293-64994 */
+  if( rc ){
+    sqlite3_result_error_code(context, rc);
+  }
+}
+
+/*
+** The replace() function.  Three arguments are all strings: call
+** them A, B, and C. The result is also a string which is derived
+** from A by replacing every occurrence of B with C.  The match
+** must be exact.  Collating sequences are not used.
+*/
+static void replaceFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zStr;        /* The input string A */
+  const unsigned char *zPattern;    /* The pattern string B */
+  const unsigned char *zRep;        /* The replacement string C */
+  unsigned char *zOut;              /* The output */
+  int nStr;                /* Size of zStr */
+  int nPattern;            /* Size of zPattern */
+  int nRep;                /* Size of zRep */
+  i64 nOut;                /* Maximum size of zOut */
+  int loopLimit;           /* Last zStr[] that might match zPattern[] */
+  int i, j;                /* Loop counters */
+  unsigned cntExpand;      /* Number zOut expansions */
+  sqlite3 *db = sqlite3_context_db_handle(context);
+
+  assert( argc==3 );
+  UNUSED_PARAMETER(argc);
+  zStr = sqlite3_value_text(argv[0]);
+  if( zStr==0 ) return;
+  nStr = sqlite3_value_bytes(argv[0]);
+  assert( zStr==sqlite3_value_text(argv[0]) );  /* No encoding change */
+  zPattern = sqlite3_value_text(argv[1]);
+  if( zPattern==0 ){
+    assert( sqlite3_value_type(argv[1])==SQLITE_NULL
+            || sqlite3_context_db_handle(context)->mallocFailed );
+    return;
+  }
+  if( zPattern[0]==0 ){
+    assert( sqlite3_value_type(argv[1])!=SQLITE_NULL );
+    sqlite3_result_text(context, (const char*)zStr, nStr, SQLITE_TRANSIENT);
+    return;
+  }
+  nPattern = sqlite3_value_bytes(argv[1]);
+  assert( zPattern==sqlite3_value_text(argv[1]) );  /* No encoding change */
+  zRep = sqlite3_value_text(argv[2]);
+  if( zRep==0 ) return;
+  nRep = sqlite3_value_bytes(argv[2]);
+  assert( zRep==sqlite3_value_text(argv[2]) );
+  nOut = nStr + 1;
+  assert( nOut<SQLITE_MAX_LENGTH );
+  zOut = contextMalloc(context, (i64)nOut);
+  if( zOut==0 ){
+    return;
+  }
+  loopLimit = nStr - nPattern;
+  cntExpand = 0;
+  for(i=j=0; i<=loopLimit; i++){
+    if( zStr[i]!=zPattern[0] || memcmp(&zStr[i], zPattern, nPattern) ){
+      zOut[j++] = zStr[i];
+    }else{
+      if( nRep>nPattern ){
+        nOut += nRep - nPattern;
+        testcase( nOut-1==db->aLimit[SQLITE_LIMIT_LENGTH] );
+        testcase( nOut-2==db->aLimit[SQLITE_LIMIT_LENGTH] );
+        if( nOut-1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+          sqlite3_result_error_toobig(context);
+          sqlite3_free(zOut);
+          return;
+        }
+        cntExpand++;
+        if( (cntExpand&(cntExpand-1))==0 ){
+          /* Grow the size of the output buffer only on substitutions
+          ** whose index is a power of two: 1, 2, 4, 8, 16, 32, ... */
+          u8 *zOld;
+          zOld = zOut;
+          zOut = sqlite3Realloc(zOut, (int)nOut + (nOut - nStr - 1));
+          if( zOut==0 ){
+            sqlite3_result_error_nomem(context);
+            sqlite3_free(zOld);
+            return;
+          }
+        }
+      }
+      memcpy(&zOut[j], zRep, nRep);
+      j += nRep;
+      i += nPattern-1;
+    }
+  }
+  assert( j+nStr-i+1<=nOut );
+  memcpy(&zOut[j], &zStr[i], nStr-i);
+  j += nStr - i;
+  assert( j<=nOut );
+  zOut[j] = 0;
+  sqlite3_result_text(context, (char*)zOut, j, sqlite3_free);
+}
+
+/*
+** Implementation of the TRIM(), LTRIM(), and RTRIM() functions.
+** The userdata is 0x1 for left trim, 0x2 for right trim, 0x3 for both.
+*/
+static void trimFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zIn;         /* Input string */
+  const unsigned char *zCharSet;    /* Set of characters to trim */
+  unsigned int nIn;                 /* Number of bytes in input */
+  int flags;                        /* 1: trimleft  2: trimright  3: trim */
+  int i;                            /* Loop counter */
+  unsigned int *aLen = 0;           /* Length of each character in zCharSet */
+  unsigned char **azChar = 0;       /* Individual characters in zCharSet */
+  int nChar;                        /* Number of characters in zCharSet */
+
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
+    return;
+  }
+  zIn = sqlite3_value_text(argv[0]);
+  if( zIn==0 ) return;
+  nIn = (unsigned)sqlite3_value_bytes(argv[0]);
+  assert( zIn==sqlite3_value_text(argv[0]) );
+  if( argc==1 ){
+    static const unsigned lenOne[] = { 1 };
+    static unsigned char * const azOne[] = { (u8*)" " };
+    nChar = 1;
+    aLen = (unsigned*)lenOne;
+    azChar = (unsigned char **)azOne;
+    zCharSet = 0;
+  }else if( (zCharSet = sqlite3_value_text(argv[1]))==0 ){
+    return;
+  }else{
+    const unsigned char *z;
+    for(z=zCharSet, nChar=0; *z; nChar++){
+      SQLITE_SKIP_UTF8(z);
+    }
+    if( nChar>0 ){
+      azChar = contextMalloc(context,
+                     ((i64)nChar)*(sizeof(char*)+sizeof(unsigned)));
+      if( azChar==0 ){
+        return;
+      }
+      aLen = (unsigned*)&azChar[nChar];
+      for(z=zCharSet, nChar=0; *z; nChar++){
+        azChar[nChar] = (unsigned char *)z;
+        SQLITE_SKIP_UTF8(z);
+        aLen[nChar] = (unsigned)(z - azChar[nChar]);
+      }
+    }
+  }
+  if( nChar>0 ){
+    flags = SQLITE_PTR_TO_INT(sqlite3_user_data(context));
+    if( flags & 1 ){
+      while( nIn>0 ){
+        unsigned int len = 0;
+        for(i=0; i<nChar; i++){
+          len = aLen[i];
+          if( len<=nIn && memcmp(zIn, azChar[i], len)==0 ) break;
+        }
+        if( i>=nChar ) break;
+        zIn += len;
+        nIn -= len;
+      }
+    }
+    if( flags & 2 ){
+      while( nIn>0 ){
+        unsigned int len = 0;
+        for(i=0; i<nChar; i++){
+          len = aLen[i];
+          if( len<=nIn && memcmp(&zIn[nIn-len],azChar[i],len)==0 ) break;
+        }
+        if( i>=nChar ) break;
+        nIn -= len;
+      }
+    }
+    if( zCharSet ){
+      sqlite3_free(azChar);
+    }
+  }
+  sqlite3_result_text(context, (char*)zIn, nIn, SQLITE_TRANSIENT);
+}
+
+/* The core implementation of the CONCAT(...) and CONCAT_WS(SEP,...)
+** functions.
+**
+** Return a string value that is the concatenation of all non-null
+** entries in argv[].  Use zSep as the separator.
+*/
+static void concatFuncCore(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv,
+  int nSep,
+  const char *zSep
+){
+  i64 j, k, n = 0;
+  int i;
+  char *z;
+  for(i=0; i<argc; i++){
+    n += sqlite3_value_bytes(argv[i]);
+  }
+  n += (argc-1)*(i64)nSep;
+  z = sqlite3_malloc64(n+1);
+  if( z==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+  j = 0;
+  for(i=0; i<argc; i++){
+    k = sqlite3_value_bytes(argv[i]);
+    if( k>0 ){
+      const char *v = (const char*)sqlite3_value_text(argv[i]);
+      if( v!=0 ){
+        if( j>0 && nSep>0 ){
+          memcpy(&z[j], zSep, nSep);
+          j += nSep;
+        }
+        memcpy(&z[j], v, k);
+        j += k;
+      }
+    }
+  }
+  z[j] = 0;
+  assert( j<=n );
+  sqlite3_result_text64(context, z, j, sqlite3_free, SQLITE_UTF8);
+}
+
+/*
+** The CONCAT(...) function.  Generate a string result that is the
+** concatentation of all non-null arguments.
+*/
+static void concatFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  concatFuncCore(context, argc, argv, 0, "");
+}
+
+/*
+** The CONCAT_WS(separator, ...) function.
+**
+** Generate a string that is the concatenation of 2nd through the Nth
+** argument.  Use the first argument (which must be non-NULL) as the
+** separator.
+*/
+static void concatwsFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int nSep = sqlite3_value_bytes(argv[0]);
+  const char *zSep = (const char*)sqlite3_value_text(argv[0]);
+  if( zSep==0 ) return;
+  concatFuncCore(context, argc-1, argv+1, nSep, zSep);
+}
+
+
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+/*
+** The "unknown" function is automatically substituted in place of
+** any unrecognized function name when doing an EXPLAIN or EXPLAIN QUERY PLAN
+** when the SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION compile-time option is used.
+** When the "sqlite3" command-line shell is built using this functionality,
+** that allows an EXPLAIN or EXPLAIN QUERY PLAN for complex queries
+** involving application-defined functions to be examined in a generic
+** sqlite3 shell.
+*/
+static void unknownFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  /* no-op */
+  (void)context;
+  (void)argc;
+  (void)argv;
+}
+#endif /*SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION*/
+
+
+/* IMP: R-25361-16150 This function is omitted from SQLite by default. It
+** is only available if the SQLITE_SOUNDEX compile-time option is used
+** when SQLite is built.
+*/
+#ifdef SQLITE_SOUNDEX
+/*
+** Compute the soundex encoding of a word.
+**
+** IMP: R-59782-00072 The soundex(X) function returns a string that is the
+** soundex encoding of the string X.
+*/
+static void soundexFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  char zResult[8];
+  const u8 *zIn;
+  int i, j;
+  static const unsigned char iCode[] = {
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
+    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
+    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
+    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
+  };
+  assert( argc==1 );
+  zIn = (u8*)sqlite3_value_text(argv[0]);
+  if( zIn==0 ) zIn = (u8*)"";
+  for(i=0; zIn[i] && !sqlite3Isalpha(zIn[i]); i++){}
+  if( zIn[i] ){
+    u8 prevcode = iCode[zIn[i]&0x7f];
+    zResult[0] = sqlite3Toupper(zIn[i]);
+    for(j=1; j<4 && zIn[i]; i++){
+      int code = iCode[zIn[i]&0x7f];
+      if( code>0 ){
+        if( code!=prevcode ){
+          prevcode = code;
+          zResult[j++] = code + '0';
+        }
+      }else{
+        prevcode = 0;
+      }
+    }
+    while( j<4 ){
+      zResult[j++] = '0';
+    }
+    zResult[j] = 0;
+    sqlite3_result_text(context, zResult, 4, SQLITE_TRANSIENT);
+  }else{
+    /* IMP: R-64894-50321 The string "?000" is returned if the argument
+    ** is NULL or contains no ASCII alphabetic characters. */
+    sqlite3_result_text(context, "?000", 4, SQLITE_STATIC);
+  }
+}
+#endif /* SQLITE_SOUNDEX */
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** A function that loads a shared-library extension then returns NULL.
+*/
+static void loadExt(sqlite3_context *context, int argc, sqlite3_value **argv){
+  const char *zFile = (const char *)sqlite3_value_text(argv[0]);
+  const char *zProc;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  char *zErrMsg = 0;
+
+  /* Disallow the load_extension() SQL function unless the SQLITE_LoadExtFunc
+  ** flag is set.  See the sqlite3_enable_load_extension() API.
+  */
+  if( (db->flags & SQLITE_LoadExtFunc)==0 ){
+    sqlite3_result_error(context, "not authorized", -1);
+    return;
+  }
+
+  if( argc==2 ){
+    zProc = (const char *)sqlite3_value_text(argv[1]);
+  }else{
+    zProc = 0;
+  }
+  if( zFile && sqlite3_load_extension(db, zFile, zProc, &zErrMsg) ){
+    sqlite3_result_error(context, zErrMsg, -1);
+    sqlite3_free(zErrMsg);
+  }
+}
+#endif
+
+
+/*
+** An instance of the following structure holds the context of a
+** sum() or avg() aggregate computation.
+*/
+typedef struct SumCtx SumCtx;
+struct SumCtx {
+  double rSum;      /* Running sum as as a double */
+  double rErr;      /* Error term for Kahan-Babushka-Neumaier summation */
+  i64 iSum;         /* Running sum as a signed integer */
+  i64 cnt;          /* Number of elements summed */
+  u8 approx;        /* True if any non-integer value was input to the sum */
+  u8 ovrfl;         /* Integer overflow seen */
+};
+
+/*
+** Do one step of the Kahan-Babushka-Neumaier summation.
+**
+** https://en.wikipedia.org/wiki/Kahan_summation_algorithm
+**
+** Variables are marked "volatile" to defeat c89 x86 floating point
+** optimizations can mess up this algorithm.
+*/
+static void kahanBabuskaNeumaierStep(
+  volatile SumCtx *pSum,
+  volatile double r
+){
+  volatile double s = pSum->rSum;
+  volatile double t = s + r;
+  if( fabs(s) > fabs(r) ){
+    pSum->rErr += (s - t) + r;
+  }else{
+    pSum->rErr += (r - t) + s;
+  }
+  pSum->rSum = t;
+}
+
+/*
+** Add a (possibly large) integer to the running sum.
+*/
+static void kahanBabuskaNeumaierStepInt64(volatile SumCtx *pSum, i64 iVal){
+  if( iVal<=-4503599627370496LL || iVal>=+4503599627370496LL ){
+    i64 iBig, iSm;
+    iSm = iVal % 16384;
+    iBig = iVal - iSm;
+    kahanBabuskaNeumaierStep(pSum, iBig);
+    kahanBabuskaNeumaierStep(pSum, iSm);
+  }else{
+    kahanBabuskaNeumaierStep(pSum, (double)iVal);
+  }
+}
+
+/*
+** Initialize the Kahan-Babaska-Neumaier sum from a 64-bit integer
+*/
+static void kahanBabuskaNeumaierInit(
+  volatile SumCtx *p,
+  i64 iVal
+){
+  if( iVal<=-4503599627370496LL || iVal>=+4503599627370496LL ){
+    i64 iSm = iVal % 16384;
+    p->rSum = (double)(iVal - iSm);
+    p->rErr = (double)iSm;
+  }else{
+    p->rSum = (double)iVal;
+    p->rErr = 0.0;
+  }
+}
+
+/*
+** Routines used to compute the sum, average, and total.
+**
+** The SUM() function follows the (broken) SQL standard which means
+** that it returns NULL if it sums over no inputs.  TOTAL returns
+** 0.0 in that case.  In addition, TOTAL always returns a float where
+** SUM might return an integer if it never encounters a floating point
+** value.  TOTAL never fails, but SUM might through an exception if
+** it overflows an integer.
+*/
+static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
+  SumCtx *p;
+  int type;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  p = sqlite3_aggregate_context(context, sizeof(*p));
+  type = sqlite3_value_numeric_type(argv[0]);
+  if( p && type!=SQLITE_NULL ){
+    p->cnt++;
+    if( p->approx==0 ){
+      if( type!=SQLITE_INTEGER ){
+        kahanBabuskaNeumaierInit(p, p->iSum);
+        p->approx = 1;
+        kahanBabuskaNeumaierStep(p, sqlite3_value_double(argv[0]));
+      }else{
+        i64 x = p->iSum;
+        if( sqlite3AddInt64(&x, sqlite3_value_int64(argv[0]))==0 ){
+          p->iSum = x;
+        }else{
+          p->ovrfl = 1;
+          kahanBabuskaNeumaierInit(p, p->iSum);
+          p->approx = 1;
+          kahanBabuskaNeumaierStepInt64(p, sqlite3_value_int64(argv[0]));
+        }
+      }
+    }else{
+      if( type==SQLITE_INTEGER ){
+        kahanBabuskaNeumaierStepInt64(p, sqlite3_value_int64(argv[0]));
+      }else{
+        p->ovrfl = 0;
+        kahanBabuskaNeumaierStep(p, sqlite3_value_double(argv[0]));
+      }
+    }
+  }
+}
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void sumInverse(sqlite3_context *context, int argc, sqlite3_value**argv){
+  SumCtx *p;
+  int type;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  p = sqlite3_aggregate_context(context, sizeof(*p));
+  type = sqlite3_value_numeric_type(argv[0]);
+  /* p is always non-NULL because sumStep() will have been called first
+  ** to initialize it */
+  if( ALWAYS(p) && type!=SQLITE_NULL ){
+    assert( p->cnt>0 );
+    p->cnt--;
+    if( !p->approx ){
+      if( sqlite3SubInt64(&p->iSum, sqlite3_value_int64(argv[0])) ){
+        p->ovrfl = 1;
+        p->approx = 1;
+      }
+    }else if( type==SQLITE_INTEGER ){
+      i64 iVal = sqlite3_value_int64(argv[0]);
+      if( iVal!=SMALLEST_INT64 ){
+        kahanBabuskaNeumaierStepInt64(p, -iVal);
+      }else{
+        kahanBabuskaNeumaierStepInt64(p, LARGEST_INT64);
+        kahanBabuskaNeumaierStepInt64(p, 1);
+      }
+    }else{
+      kahanBabuskaNeumaierStep(p, -sqlite3_value_double(argv[0]));
+    }
+  }
+}
+#else
+# define sumInverse 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+static void sumFinalize(sqlite3_context *context){
+  SumCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  if( p && p->cnt>0 ){
+    if( p->approx ){
+      if( p->ovrfl ){
+        sqlite3_result_error(context,"integer overflow",-1);
+      }else if( !sqlite3IsOverflow(p->rErr) ){
+        sqlite3_result_double(context, p->rSum+p->rErr);
+      }else{
+        sqlite3_result_double(context, p->rSum);
+      }
+    }else{
+      sqlite3_result_int64(context, p->iSum);
+    }
+  }
+}
+static void avgFinalize(sqlite3_context *context){
+  SumCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  if( p && p->cnt>0 ){
+    double r;
+    if( p->approx ){
+      r = p->rSum;
+      if( !sqlite3IsOverflow(p->rErr) ) r += p->rErr;
+    }else{
+      r = (double)(p->iSum);
+    }
+    sqlite3_result_double(context, r/(double)p->cnt);
+  }
+}
+static void totalFinalize(sqlite3_context *context){
+  SumCtx *p;
+  double r = 0.0;
+  p = sqlite3_aggregate_context(context, 0);
+  if( p ){
+    if( p->approx ){
+      r = p->rSum;
+      if( !sqlite3IsOverflow(p->rErr) ) r += p->rErr;
+    }else{
+      r = (double)(p->iSum);
+    }
+  }
+  sqlite3_result_double(context, r);
+}
+
+/*
+** The following structure keeps track of state information for the
+** count() aggregate function.
+*/
+typedef struct CountCtx CountCtx;
+struct CountCtx {
+  i64 n;
+#ifdef SQLITE_DEBUG
+  int bInverse;                   /* True if xInverse() ever called */
+#endif
+};
+
+/*
+** Routines to implement the count() aggregate function.
+*/
+static void countStep(sqlite3_context *context, int argc, sqlite3_value **argv){
+  CountCtx *p;
+  p = sqlite3_aggregate_context(context, sizeof(*p));
+  if( (argc==0 || SQLITE_NULL!=sqlite3_value_type(argv[0])) && p ){
+    p->n++;
+  }
+
+#ifndef SQLITE_OMIT_DEPRECATED
+  /* The sqlite3_aggregate_count() function is deprecated.  But just to make
+  ** sure it still operates correctly, verify that its count agrees with our
+  ** internal count when using count(*) and when the total count can be
+  ** expressed as a 32-bit integer. */
+  assert( argc==1 || p==0 || p->n>0x7fffffff || p->bInverse
+          || p->n==sqlite3_aggregate_count(context) );
+#endif
+}
+static void countFinalize(sqlite3_context *context){
+  CountCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  sqlite3_result_int64(context, p ? p->n : 0);
+}
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void countInverse(sqlite3_context *ctx, int argc, sqlite3_value **argv){
+  CountCtx *p;
+  p = sqlite3_aggregate_context(ctx, sizeof(*p));
+  /* p is always non-NULL since countStep() will have been called first */
+  if( (argc==0 || SQLITE_NULL!=sqlite3_value_type(argv[0])) && ALWAYS(p) ){
+    p->n--;
+#ifdef SQLITE_DEBUG
+    p->bInverse = 1;
+#endif
+  }
+}
+#else
+# define countInverse 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** Routines to implement min() and max() aggregate functions.
+*/
+static void minmaxStep(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  Mem *pArg  = (Mem *)argv[0];
+  Mem *pBest;
+  UNUSED_PARAMETER(NotUsed);
+
+  pBest = (Mem *)sqlite3_aggregate_context(context, sizeof(*pBest));
+  if( !pBest ) return;
+
+  if( sqlite3_value_type(pArg)==SQLITE_NULL ){
+    if( pBest->flags ) sqlite3SkipAccumulatorLoad(context);
+  }else if( pBest->flags ){
+    int max;
+    int cmp;
+    CollSeq *pColl = sqlite3GetFuncCollSeq(context);
+    /* This step function is used for both the min() and max() aggregates,
+    ** the only difference between the two being that the sense of the
+    ** comparison is inverted. For the max() aggregate, the
+    ** sqlite3_user_data() function returns (void *)-1. For min() it
+    ** returns (void *)db, where db is the sqlite3* database pointer.
+    ** Therefore the next statement sets variable 'max' to 1 for the max()
+    ** aggregate, or 0 for min().
+    */
+    max = sqlite3_user_data(context)!=0;
+    cmp = sqlite3MemCompare(pBest, pArg, pColl);
+    if( (max && cmp<0) || (!max && cmp>0) ){
+      sqlite3VdbeMemCopy(pBest, pArg);
+    }else{
+      sqlite3SkipAccumulatorLoad(context);
+    }
+  }else{
+    pBest->db = sqlite3_context_db_handle(context);
+    sqlite3VdbeMemCopy(pBest, pArg);
+  }
+}
+static void minMaxValueFinalize(sqlite3_context *context, int bValue){
+  sqlite3_value *pRes;
+  pRes = (sqlite3_value *)sqlite3_aggregate_context(context, 0);
+  if( pRes ){
+    if( pRes->flags ){
+      sqlite3_result_value(context, pRes);
+    }
+    if( bValue==0 ) sqlite3VdbeMemRelease(pRes);
+  }
+}
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void minMaxValue(sqlite3_context *context){
+  minMaxValueFinalize(context, 1);
+}
+#else
+# define minMaxValue 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+static void minMaxFinalize(sqlite3_context *context){
+  minMaxValueFinalize(context, 0);
+}
+
+/*
+** group_concat(EXPR, ?SEPARATOR?)
+** string_agg(EXPR, SEPARATOR)
+**
+** Content is accumulated in GroupConcatCtx.str with the SEPARATOR
+** coming before the EXPR value, except for the first entry which
+** omits the SEPARATOR.
+**
+** It is tragic that the SEPARATOR goes before the EXPR string.  The
+** groupConcatInverse() implementation would have been easier if the
+** SEPARATOR were appended after EXPR.  And the order is undocumented,
+** so we could change it, in theory.  But the old behavior has been
+** around for so long that we dare not, for fear of breaking something.
+*/
+typedef struct {
+  StrAccum str;          /* The accumulated concatenation */
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  int nAccum;            /* Number of strings presently concatenated */
+  int nFirstSepLength;   /* Used to detect separator length change */
+  /* If pnSepLengths!=0, refs an array of inter-string separator lengths,
+  ** stored as actually incorporated into presently accumulated result.
+  ** (Hence, its slots in use number nAccum-1 between method calls.)
+  ** If pnSepLengths==0, nFirstSepLength is the length used throughout.
+  */
+  int *pnSepLengths;
+#endif
+} GroupConcatCtx;
+
+static void groupConcatStep(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *zVal;
+  GroupConcatCtx *pGCC;
+  const char *zSep;
+  int nVal, nSep;
+  assert( argc==1 || argc==2 );
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  pGCC = (GroupConcatCtx*)sqlite3_aggregate_context(context, sizeof(*pGCC));
+  if( pGCC ){
+    sqlite3 *db = sqlite3_context_db_handle(context);
+    int firstTerm = pGCC->str.mxAlloc==0;
+    pGCC->str.mxAlloc = db->aLimit[SQLITE_LIMIT_LENGTH];
+    if( argc==1 ){
+      if( !firstTerm ){
+        sqlite3_str_appendchar(&pGCC->str, 1, ',');
+      }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      else{
+        pGCC->nFirstSepLength = 1;
+      }
+#endif
+    }else if( !firstTerm ){
+      zSep = (char*)sqlite3_value_text(argv[1]);
+      nSep = sqlite3_value_bytes(argv[1]);
+      if( zSep ){
+        sqlite3_str_append(&pGCC->str, zSep, nSep);
+      }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      else{
+        nSep = 0;
+      }
+      if( nSep != pGCC->nFirstSepLength || pGCC->pnSepLengths != 0 ){
+        int *pnsl = pGCC->pnSepLengths;
+        if( pnsl == 0 ){
+          /* First separator length variation seen, start tracking them. */
+          pnsl = (int*)sqlite3_malloc64((pGCC->nAccum+1) * sizeof(int));
+          if( pnsl!=0 ){
+            int i = 0, nA = pGCC->nAccum-1;
+            while( i<nA ) pnsl[i++] = pGCC->nFirstSepLength;
+          }
+        }else{
+          pnsl = (int*)sqlite3_realloc64(pnsl, pGCC->nAccum * sizeof(int));
+        }
+        if( pnsl!=0 ){
+          if( ALWAYS(pGCC->nAccum>0) ){
+            pnsl[pGCC->nAccum-1] = nSep;
+          }
+          pGCC->pnSepLengths = pnsl;
+        }else{
+          sqlite3StrAccumSetError(&pGCC->str, SQLITE_NOMEM);
+        }
+      }
+#endif
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    else{
+      pGCC->nFirstSepLength = sqlite3_value_bytes(argv[1]);
+    }
+    pGCC->nAccum += 1;
+#endif
+    zVal = (char*)sqlite3_value_text(argv[0]);
+    nVal = sqlite3_value_bytes(argv[0]);
+    if( zVal ) sqlite3_str_append(&pGCC->str, zVal, nVal);
+  }
+}
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void groupConcatInverse(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GroupConcatCtx *pGCC;
+  assert( argc==1 || argc==2 );
+  (void)argc;  /* Suppress unused parameter warning */
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  pGCC = (GroupConcatCtx*)sqlite3_aggregate_context(context, sizeof(*pGCC));
+  /* pGCC is always non-NULL since groupConcatStep() will have always
+  ** run first to initialize it */
+  if( ALWAYS(pGCC) ){
+    int nVS;  /* Number of characters to remove */
+    /* Must call sqlite3_value_text() to convert the argument into text prior
+    ** to invoking sqlite3_value_bytes(), in case the text encoding is UTF16 */
+    (void)sqlite3_value_text(argv[0]);
+    nVS = sqlite3_value_bytes(argv[0]);
+    pGCC->nAccum -= 1;
+    if( pGCC->pnSepLengths!=0 ){
+      assert(pGCC->nAccum >= 0);
+      if( pGCC->nAccum>0 ){
+        nVS += *pGCC->pnSepLengths;
+        memmove(pGCC->pnSepLengths, pGCC->pnSepLengths+1,
+               (pGCC->nAccum-1)*sizeof(int));
+      }
+    }else{
+      /* If removing single accumulated string, harmlessly over-do. */
+      nVS += pGCC->nFirstSepLength;
+    }
+    if( nVS>=(int)pGCC->str.nChar ){
+      pGCC->str.nChar = 0;
+    }else{
+      pGCC->str.nChar -= nVS;
+      memmove(pGCC->str.zText, &pGCC->str.zText[nVS], pGCC->str.nChar);
+    }
+    if( pGCC->str.nChar==0 ){
+      pGCC->str.mxAlloc = 0;
+      sqlite3_free(pGCC->pnSepLengths);
+      pGCC->pnSepLengths = 0;
+    }
+  }
+}
+#else
+# define groupConcatInverse 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+static void groupConcatFinalize(sqlite3_context *context){
+  GroupConcatCtx *pGCC
+    = (GroupConcatCtx*)sqlite3_aggregate_context(context, 0);
+  if( pGCC ){
+    sqlite3ResultStrAccum(context, &pGCC->str);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    sqlite3_free(pGCC->pnSepLengths);
+#endif
+  }
+}
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void groupConcatValue(sqlite3_context *context){
+  GroupConcatCtx *pGCC
+    = (GroupConcatCtx*)sqlite3_aggregate_context(context, 0);
+  if( pGCC ){
+    StrAccum *pAccum = &pGCC->str;
+    if( pAccum->accError==SQLITE_TOOBIG ){
+      sqlite3_result_error_toobig(context);
+    }else if( pAccum->accError==SQLITE_NOMEM ){
+      sqlite3_result_error_nomem(context);
+    }else if( pGCC->nAccum>0 && pAccum->nChar==0 ){
+      sqlite3_result_text(context, "", 1, SQLITE_STATIC);
+    }else{
+      const char *zText = sqlite3_str_value(pAccum);
+      sqlite3_result_text(context, zText, pAccum->nChar, SQLITE_TRANSIENT);
+    }
+  }
+}
+#else
+# define groupConcatValue 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** This routine does per-connection function registration.  Most
+** of the built-in functions above are part of the global function set.
+** This routine only deals with those that are not global.
+*/
+SQLITE_PRIVATE void sqlite3RegisterPerConnectionBuiltinFunctions(sqlite3 *db){
+  int rc = sqlite3_overload_function(db, "MATCH", 2);
+  assert( rc==SQLITE_NOMEM || rc==SQLITE_OK );
+  if( rc==SQLITE_NOMEM ){
+    sqlite3OomFault(db);
+  }
+}
+
+/*
+** Re-register the built-in LIKE functions.  The caseSensitive
+** parameter determines whether or not the LIKE operator is case
+** sensitive.
+*/
+SQLITE_PRIVATE void sqlite3RegisterLikeFunctions(sqlite3 *db, int caseSensitive){
+  FuncDef *pDef;
+  struct compareInfo *pInfo;
+  int flags;
+  int nArg;
+  if( caseSensitive ){
+    pInfo = (struct compareInfo*)&likeInfoAlt;
+    flags = SQLITE_FUNC_LIKE | SQLITE_FUNC_CASE;
+  }else{
+    pInfo = (struct compareInfo*)&likeInfoNorm;
+    flags = SQLITE_FUNC_LIKE;
+  }
+  for(nArg=2; nArg<=3; nArg++){
+    sqlite3CreateFunc(db, "like", nArg, SQLITE_UTF8, pInfo, likeFunc,
+                      0, 0, 0, 0, 0);
+    pDef = sqlite3FindFunction(db, "like", nArg, SQLITE_UTF8, 0);
+    pDef->funcFlags |= flags;
+    pDef->funcFlags &= ~SQLITE_FUNC_UNSAFE;
+  }
+}
+
+/*
+** pExpr points to an expression which implements a function.  If
+** it is appropriate to apply the LIKE optimization to that function
+** then set aWc[0] through aWc[2] to the wildcard characters and the
+** escape character and then return TRUE.  If the function is not a
+** LIKE-style function then return FALSE.
+**
+** The expression "a LIKE b ESCAPE c" is only considered a valid LIKE
+** operator if c is a string literal that is exactly one byte in length.
+** That one byte is stored in aWc[3].  aWc[3] is set to zero if there is
+** no ESCAPE clause.
+**
+** *pIsNocase is set to true if uppercase and lowercase are equivalent for
+** the function (default for LIKE).  If the function makes the distinction
+** between uppercase and lowercase (as does GLOB) then *pIsNocase is set to
+** false.
+*/
+SQLITE_PRIVATE int sqlite3IsLikeFunction(sqlite3 *db, Expr *pExpr, int *pIsNocase, char *aWc){
+  FuncDef *pDef;
+  int nExpr;
+  assert( pExpr!=0 );
+  assert( pExpr->op==TK_FUNCTION );
+  assert( ExprUseXList(pExpr) );
+  if( !pExpr->x.pList ){
+    return 0;
+  }
+  nExpr = pExpr->x.pList->nExpr;
+  assert( !ExprHasProperty(pExpr, EP_IntValue) );
+  pDef = sqlite3FindFunction(db, pExpr->u.zToken, nExpr, SQLITE_UTF8, 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+  if( pDef==0 ) return 0;
+#endif
+  if( NEVER(pDef==0) || (pDef->funcFlags & SQLITE_FUNC_LIKE)==0 ){
+    return 0;
+  }
+
+  /* The memcpy() statement assumes that the wildcard characters are
+  ** the first three statements in the compareInfo structure.  The
+  ** asserts() that follow verify that assumption
+  */
+  memcpy(aWc, pDef->pUserData, 3);
+  assert( (char*)&likeInfoAlt == (char*)&likeInfoAlt.matchAll );
+  assert( &((char*)&likeInfoAlt)[1] == (char*)&likeInfoAlt.matchOne );
+  assert( &((char*)&likeInfoAlt)[2] == (char*)&likeInfoAlt.matchSet );
+
+  if( nExpr<3 ){
+    aWc[3] = 0;
+  }else{
+    Expr *pEscape = pExpr->x.pList->a[2].pExpr;
+    char *zEscape;
+    if( pEscape->op!=TK_STRING ) return 0;
+    assert( !ExprHasProperty(pEscape, EP_IntValue) );
+    zEscape = pEscape->u.zToken;
+    if( zEscape[0]==0 || zEscape[1]!=0 ) return 0;
+    if( zEscape[0]==aWc[0] ) return 0;
+    if( zEscape[0]==aWc[1] ) return 0;
+    aWc[3] = zEscape[0];
+  }
+
+  *pIsNocase = (pDef->funcFlags & SQLITE_FUNC_CASE)==0;
+  return 1;
+}
+
+/* Mathematical Constants */
+#ifndef M_PI
+# define M_PI   3.141592653589793238462643383279502884
+#endif
+#ifndef M_LN10
+# define M_LN10 2.302585092994045684017991454684364208
+#endif
+#ifndef M_LN2
+# define M_LN2  0.693147180559945309417232121458176568
+#endif
+
+
+/* Extra math functions that require linking with -lm
+*/
+#ifdef SQLITE_ENABLE_MATH_FUNCTIONS
+/*
+** Implementation SQL functions:
+**
+**   ceil(X)
+**   ceiling(X)
+**   floor(X)
+**
+** The sqlite3_user_data() pointer is a pointer to the libm implementation
+** of the underlying C function.
+*/
+static void ceilingFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( argc==1 );
+  switch( sqlite3_value_numeric_type(argv[0]) ){
+    case SQLITE_INTEGER: {
+       sqlite3_result_int64(context, sqlite3_value_int64(argv[0]));
+       break;
+    }
+    case SQLITE_FLOAT: {
+       double (*x)(double) = (double(*)(double))sqlite3_user_data(context);
+       sqlite3_result_double(context, x(sqlite3_value_double(argv[0])));
+       break;
+    }
+    default: {
+       break;
+    }
+  }
+}
+
+/*
+** On some systems, ceil() and floor() are intrinsic function.  You are
+** unable to take a pointer to these functions.  Hence, we here wrap them
+** in our own actual functions.
+*/
+static double xCeil(double x){ return ceil(x); }
+static double xFloor(double x){ return floor(x); }
+
+/*
+** Some systems do not have log2() and log10() in their standard math
+** libraries.
+*/
+#if defined(HAVE_LOG10) && HAVE_LOG10==0
+# define log10(X) (0.4342944819032517867*log(X))
+#endif
+#if defined(HAVE_LOG2) && HAVE_LOG2==0
+# define log2(X) (1.442695040888963456*log(X))
+#endif
+
+
+/*
+** Implementation of SQL functions:
+**
+**   ln(X)       - natural logarithm
+**   log(X)      - log X base 10
+**   log10(X)    - log X base 10
+**   log(B,X)    - log X base B
+*/
+static void logFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  double x, b, ans;
+  assert( argc==1 || argc==2 );
+  switch( sqlite3_value_numeric_type(argv[0]) ){
+    case SQLITE_INTEGER:
+    case SQLITE_FLOAT:
+      x = sqlite3_value_double(argv[0]);
+      if( x<=0.0 ) return;
+      break;
+    default:
+      return;
+  }
+  if( argc==2 ){
+    switch( sqlite3_value_numeric_type(argv[0]) ){
+      case SQLITE_INTEGER:
+      case SQLITE_FLOAT:
+        b = log(x);
+        if( b<=0.0 ) return;
+        x = sqlite3_value_double(argv[1]);
+        if( x<=0.0 ) return;
+        break;
+     default:
+        return;
+    }
+    ans = log(x)/b;
+  }else{
+    switch( SQLITE_PTR_TO_INT(sqlite3_user_data(context)) ){
+      case 1:
+        ans = log10(x);
+        break;
+      case 2:
+        ans = log2(x);
+        break;
+      default:
+        ans = log(x);
+        break;
+    }
+  }
+  sqlite3_result_double(context, ans);
+}
+
+/*
+** Functions to converts degrees to radians and radians to degrees.
+*/
+static double degToRad(double x){ return x*(M_PI/180.0); }
+static double radToDeg(double x){ return x*(180.0/M_PI); }
+
+/*
+** Implementation of 1-argument SQL math functions:
+**
+**   exp(X)  - Compute e to the X-th power
+*/
+static void math1Func(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int type0;
+  double v0, ans;
+  double (*x)(double);
+  assert( argc==1 );
+  type0 = sqlite3_value_numeric_type(argv[0]);
+  if( type0!=SQLITE_INTEGER && type0!=SQLITE_FLOAT ) return;
+  v0 = sqlite3_value_double(argv[0]);
+  x = (double(*)(double))sqlite3_user_data(context);
+  ans = x(v0);
+  sqlite3_result_double(context, ans);
+}
+
+/*
+** Implementation of 2-argument SQL math functions:
+**
+**   power(X,Y)  - Compute X to the Y-th power
+*/
+static void math2Func(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int type0, type1;
+  double v0, v1, ans;
+  double (*x)(double,double);
+  assert( argc==2 );
+  type0 = sqlite3_value_numeric_type(argv[0]);
+  if( type0!=SQLITE_INTEGER && type0!=SQLITE_FLOAT ) return;
+  type1 = sqlite3_value_numeric_type(argv[1]);
+  if( type1!=SQLITE_INTEGER && type1!=SQLITE_FLOAT ) return;
+  v0 = sqlite3_value_double(argv[0]);
+  v1 = sqlite3_value_double(argv[1]);
+  x = (double(*)(double,double))sqlite3_user_data(context);
+  ans = x(v0, v1);
+  sqlite3_result_double(context, ans);
+}
+
+/*
+** Implementation of 0-argument pi() function.
+*/
+static void piFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( argc==0 );
+  (void)argv;
+  sqlite3_result_double(context, M_PI);
+}
+
+#endif /* SQLITE_ENABLE_MATH_FUNCTIONS */
+
+/*
+** Implementation of sign(X) function.
+*/
+static void signFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int type0;
+  double x;
+  UNUSED_PARAMETER(argc);
+  assert( argc==1 );
+  type0 = sqlite3_value_numeric_type(argv[0]);
+  if( type0!=SQLITE_INTEGER && type0!=SQLITE_FLOAT ) return;
+  x = sqlite3_value_double(argv[0]);
+  sqlite3_result_int(context, x<0.0 ? -1 : x>0.0 ? +1 : 0);
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Implementation of fpdecode(x,y,z) function.
+**
+** x is a real number that is to be decoded.  y is the precision.
+** z is the maximum real precision.  Return a string that shows the
+** results of the sqlite3FpDecode() function.
+**
+** Used for testing and debugging only, specifically testing and debugging
+** of the sqlite3FpDecode() function.  This SQL function does not appear
+** in production builds.  This function is not an API and is subject to
+** modification or removal in future versions of SQLite.
+*/
+static void fpdecodeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  FpDecode s;
+  double x;
+  int y, z;
+  char zBuf[100];
+  UNUSED_PARAMETER(argc);
+  assert( argc==3 );
+  x = sqlite3_value_double(argv[0]);
+  y = sqlite3_value_int(argv[1]);
+  z = sqlite3_value_int(argv[2]);
+  if( z<=0 ) z = 1;
+  sqlite3FpDecode(&s, x, y, z);
+  if( s.isSpecial==2 ){
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "NaN");
+  }else{
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "%c%.*s/%d", s.sign, s.n, s.z, s.iDP);
+  }
+  sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+}
+#endif /* SQLITE_DEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+** Implementation of parseuri(uri,flags) function.
+**
+** Required Arguments:
+**    "uri"        The URI to parse.
+**    "flags"      Bitmask of flags, as if to sqlite3_open_v2().
+**
+** Additional arguments beyond the first two make calls to
+** sqlite3_uri_key() for integers and sqlite3_uri_parameter for
+** anything else.
+**
+** The result is a string showing the results of calling sqlite3ParseUri().
+**
+** Used for testing and debugging only, specifically testing and debugging
+** of the sqlite3ParseUri() function.  This SQL function does not appear
+** in production builds.  This function is not an API and is subject to
+** modification or removal in future versions of SQLite.
+*/
+static void parseuriFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_str *pResult;
+  const char *zVfs;
+  const char *zUri;
+  unsigned int flgs;
+  int rc;
+  sqlite3_vfs *pVfs = 0;
+  char *zFile = 0;
+  char *zErr = 0;
+
+  if( argc<2 ) return;
+  pVfs = sqlite3_vfs_find(0);
+  assert( pVfs );
+  zVfs = pVfs->zName;
+  zUri = (const char*)sqlite3_value_text(argv[0]);
+  if( zUri==0 ) return;
+  flgs = (unsigned int)sqlite3_value_int(argv[1]);
+  rc = sqlite3ParseUri(zVfs, zUri, &flgs, &pVfs, &zFile, &zErr);
+  pResult = sqlite3_str_new(0);
+  if( pResult ){
+    int i;
+    sqlite3_str_appendf(pResult, "rc=%d", rc);
+    sqlite3_str_appendf(pResult, ", flags=0x%x", flgs);
+    sqlite3_str_appendf(pResult, ", vfs=%Q", pVfs ? pVfs->zName: 0);
+    sqlite3_str_appendf(pResult, ", err=%Q", zErr);
+    sqlite3_str_appendf(pResult, ", file=%Q", zFile);
+    if( zFile ){
+      const char *z = zFile;
+      z += sqlite3Strlen30(z)+1;
+      while( z[0] ){
+        sqlite3_str_appendf(pResult, ", %Q", z);
+        z += sqlite3Strlen30(z)+1;
+      }
+      for(i=2; i<argc; i++){
+        const char *zArg;
+        if( sqlite3_value_type(argv[i])==SQLITE_INTEGER ){
+          int k = sqlite3_value_int(argv[i]);
+          sqlite3_str_appendf(pResult, ", '%d:%q'",k,sqlite3_uri_key(zFile, k));
+        }else if( (zArg = (const char*)sqlite3_value_text(argv[i]))!=0 ){
+          sqlite3_str_appendf(pResult, ", '%q:%q'",
+                 zArg, sqlite3_uri_parameter(zFile,zArg));
+        }else{
+          sqlite3_str_appendf(pResult, ", NULL");
+        }
+      }
+    }
+    sqlite3_result_text(ctx, sqlite3_str_finish(pResult), -1, sqlite3_free);
+  }
+  sqlite3_free_filename(zFile);
+  sqlite3_free(zErr);
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** All of the FuncDef structures in the aBuiltinFunc[] array above
+** to the global function hash table.  This occurs at start-time (as
+** a consequence of calling sqlite3_initialize()).
+**
+** After this routine runs
+*/
+SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(void){
+  /*
+  ** The following array holds FuncDef structures for all of the functions
+  ** defined in this file.
+  **
+  ** The array cannot be constant since changes are made to the
+  ** FuncDef.pHash elements at start-time.  The elements of this array
+  ** are read-only after initialization is complete.
+  **
+  ** For peak efficiency, put the most frequently used function last.
+  */
+  static FuncDef aBuiltinFunc[] = {
+/***** Functions only available with SQLITE_TESTCTRL_INTERNAL_FUNCTIONS *****/
+#if !defined(SQLITE_UNTESTABLE)
+    TEST_FUNC(implies_nonnull_row, 2, INLINEFUNC_implies_nonnull_row, 0),
+    TEST_FUNC(expr_compare,        2, INLINEFUNC_expr_compare,        0),
+    TEST_FUNC(expr_implies_expr,   2, INLINEFUNC_expr_implies_expr,   0),
+    TEST_FUNC(affinity,            1, INLINEFUNC_affinity,            0),
+#endif /* !defined(SQLITE_UNTESTABLE) */
+/***** Regular functions *****/
+#ifdef SQLITE_SOUNDEX
+    FUNCTION(soundex,            1, 0, 0, soundexFunc      ),
+#endif
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+    SFUNCTION(load_extension,    1, 0, 0, loadExt          ),
+    SFUNCTION(load_extension,    2, 0, 0, loadExt          ),
+#endif
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+    DFUNCTION(sqlite_compileoption_used,1, 0, 0, compileoptionusedFunc  ),
+    DFUNCTION(sqlite_compileoption_get, 1, 0, 0, compileoptiongetFunc  ),
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+    INLINE_FUNC(unlikely,        1, INLINEFUNC_unlikely, SQLITE_FUNC_UNLIKELY),
+    INLINE_FUNC(likelihood,      2, INLINEFUNC_unlikely, SQLITE_FUNC_UNLIKELY),
+    INLINE_FUNC(likely,          1, INLINEFUNC_unlikely, SQLITE_FUNC_UNLIKELY),
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+    INLINE_FUNC(sqlite_offset,   1, INLINEFUNC_sqlite_offset, 0 ),
+#endif
+    FUNCTION(ltrim,              1, 1, 0, trimFunc         ),
+    FUNCTION(ltrim,              2, 1, 0, trimFunc         ),
+    FUNCTION(rtrim,              1, 2, 0, trimFunc         ),
+    FUNCTION(rtrim,              2, 2, 0, trimFunc         ),
+    FUNCTION(trim,               1, 3, 0, trimFunc         ),
+    FUNCTION(trim,               2, 3, 0, trimFunc         ),
+    FUNCTION(min,               -3, 0, 1, minmaxFunc       ),
+    WAGGREGATE(min, 1, 0, 1, minmaxStep, minMaxFinalize, minMaxValue, 0,
+                                 SQLITE_FUNC_MINMAX|SQLITE_FUNC_ANYORDER ),
+    FUNCTION(max,               -3, 1, 1, minmaxFunc       ),
+    WAGGREGATE(max, 1, 1, 1, minmaxStep, minMaxFinalize, minMaxValue, 0,
+                                 SQLITE_FUNC_MINMAX|SQLITE_FUNC_ANYORDER ),
+    FUNCTION2(typeof,            1, 0, 0, typeofFunc,  SQLITE_FUNC_TYPEOF),
+    FUNCTION2(subtype,           1, 0, 0, subtypeFunc,
+                                           SQLITE_FUNC_TYPEOF|SQLITE_SUBTYPE),
+    FUNCTION2(length,            1, 0, 0, lengthFunc,  SQLITE_FUNC_LENGTH),
+    FUNCTION2(octet_length,      1, 0, 0, bytelengthFunc,SQLITE_FUNC_BYTELEN),
+    FUNCTION(instr,              2, 0, 0, instrFunc        ),
+    FUNCTION(printf,            -1, 0, 0, printfFunc       ),
+    FUNCTION(format,            -1, 0, 0, printfFunc       ),
+    FUNCTION(unicode,            1, 0, 0, unicodeFunc      ),
+    FUNCTION(char,              -1, 0, 0, charFunc         ),
+    FUNCTION(abs,                1, 0, 0, absFunc          ),
+#ifdef SQLITE_DEBUG
+    FUNCTION(fpdecode,           3, 0, 0, fpdecodeFunc     ),
+    FUNCTION(parseuri,          -1, 0, 0, parseuriFunc     ),
+#endif
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    FUNCTION(round,              1, 0, 0, roundFunc        ),
+    FUNCTION(round,              2, 0, 0, roundFunc        ),
+#endif
+    FUNCTION(upper,              1, 0, 0, upperFunc        ),
+    FUNCTION(lower,              1, 0, 0, lowerFunc        ),
+    FUNCTION(hex,                1, 0, 0, hexFunc          ),
+    FUNCTION(unhex,              1, 0, 0, unhexFunc        ),
+    FUNCTION(unhex,              2, 0, 0, unhexFunc        ),
+    FUNCTION(concat,            -3, 0, 0, concatFunc       ),
+    FUNCTION(concat_ws,         -4, 0, 0, concatwsFunc     ),
+    INLINE_FUNC(ifnull,          2, INLINEFUNC_coalesce, 0 ),
+    VFUNCTION(random,            0, 0, 0, randomFunc       ),
+    VFUNCTION(randomblob,        1, 0, 0, randomBlob       ),
+    FUNCTION(nullif,             2, 0, 1, nullifFunc       ),
+    DFUNCTION(sqlite_version,    0, 0, 0, versionFunc      ),
+    DFUNCTION(sqlite_source_id,  0, 0, 0, sourceidFunc     ),
+    FUNCTION(sqlite_log,         2, 0, 0, errlogFunc       ),
+    FUNCTION(quote,              1, 0, 0, quoteFunc        ),
+    VFUNCTION(last_insert_rowid, 0, 0, 0, last_insert_rowid),
+    VFUNCTION(changes,           0, 0, 0, changes          ),
+    VFUNCTION(total_changes,     0, 0, 0, total_changes    ),
+    FUNCTION(replace,            3, 0, 0, replaceFunc      ),
+    FUNCTION(zeroblob,           1, 0, 0, zeroblobFunc     ),
+    FUNCTION(substr,             2, 0, 0, substrFunc       ),
+    FUNCTION(substr,             3, 0, 0, substrFunc       ),
+    FUNCTION(substring,          2, 0, 0, substrFunc       ),
+    FUNCTION(substring,          3, 0, 0, substrFunc       ),
+    WAGGREGATE(sum,   1,0,0, sumStep, sumFinalize, sumFinalize, sumInverse, 0),
+    WAGGREGATE(total, 1,0,0, sumStep,totalFinalize,totalFinalize,sumInverse, 0),
+    WAGGREGATE(avg,   1,0,0, sumStep, avgFinalize, avgFinalize, sumInverse, 0),
+    WAGGREGATE(count, 0,0,0, countStep,
+        countFinalize, countFinalize, countInverse,
+        SQLITE_FUNC_COUNT|SQLITE_FUNC_ANYORDER  ),
+    WAGGREGATE(count, 1,0,0, countStep,
+        countFinalize, countFinalize, countInverse, SQLITE_FUNC_ANYORDER ),
+    WAGGREGATE(group_concat, 1, 0, 0, groupConcatStep,
+        groupConcatFinalize, groupConcatValue, groupConcatInverse, 0),
+    WAGGREGATE(group_concat, 2, 0, 0, groupConcatStep,
+        groupConcatFinalize, groupConcatValue, groupConcatInverse, 0),
+    WAGGREGATE(string_agg,   2, 0, 0, groupConcatStep,
+        groupConcatFinalize, groupConcatValue, groupConcatInverse, 0),
+
+    LIKEFUNC(glob, 2, &globInfo, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),
+#ifdef SQLITE_CASE_SENSITIVE_LIKE
+    LIKEFUNC(like, 2, &likeInfoAlt, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),
+    LIKEFUNC(like, 3, &likeInfoAlt, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),
+#else
+    LIKEFUNC(like, 2, &likeInfoNorm, SQLITE_FUNC_LIKE),
+    LIKEFUNC(like, 3, &likeInfoNorm, SQLITE_FUNC_LIKE),
+#endif
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+    FUNCTION(unknown,           -1, 0, 0, unknownFunc      ),
+#endif
+#ifdef SQLITE_ENABLE_MATH_FUNCTIONS
+    MFUNCTION(ceil,              1, xCeil,     ceilingFunc ),
+    MFUNCTION(ceiling,           1, xCeil,     ceilingFunc ),
+    MFUNCTION(floor,             1, xFloor,    ceilingFunc ),
+#if SQLITE_HAVE_C99_MATH_FUNCS
+    MFUNCTION(trunc,             1, trunc,     ceilingFunc ),
+#endif
+    FUNCTION(ln,                 1, 0, 0,      logFunc     ),
+    FUNCTION(log,                1, 1, 0,      logFunc     ),
+    FUNCTION(log10,              1, 1, 0,      logFunc     ),
+    FUNCTION(log2,               1, 2, 0,      logFunc     ),
+    FUNCTION(log,                2, 0, 0,      logFunc     ),
+    MFUNCTION(exp,               1, exp,       math1Func   ),
+    MFUNCTION(pow,               2, pow,       math2Func   ),
+    MFUNCTION(power,             2, pow,       math2Func   ),
+    MFUNCTION(mod,               2, fmod,      math2Func   ),
+    MFUNCTION(acos,              1, acos,      math1Func   ),
+    MFUNCTION(asin,              1, asin,      math1Func   ),
+    MFUNCTION(atan,              1, atan,      math1Func   ),
+    MFUNCTION(atan2,             2, atan2,     math2Func   ),
+    MFUNCTION(cos,               1, cos,       math1Func   ),
+    MFUNCTION(sin,               1, sin,       math1Func   ),
+    MFUNCTION(tan,               1, tan,       math1Func   ),
+    MFUNCTION(cosh,              1, cosh,      math1Func   ),
+    MFUNCTION(sinh,              1, sinh,      math1Func   ),
+    MFUNCTION(tanh,              1, tanh,      math1Func   ),
+#if SQLITE_HAVE_C99_MATH_FUNCS
+    MFUNCTION(acosh,             1, acosh,     math1Func   ),
+    MFUNCTION(asinh,             1, asinh,     math1Func   ),
+    MFUNCTION(atanh,             1, atanh,     math1Func   ),
+#endif
+    MFUNCTION(sqrt,              1, sqrt,      math1Func   ),
+    MFUNCTION(radians,           1, degToRad,  math1Func   ),
+    MFUNCTION(degrees,           1, radToDeg,  math1Func   ),
+    MFUNCTION(pi,                0, 0,         piFunc      ),
+#endif /* SQLITE_ENABLE_MATH_FUNCTIONS */
+    FUNCTION(sign,               1, 0, 0,      signFunc    ),
+    INLINE_FUNC(coalesce,       -4, INLINEFUNC_coalesce, 0 ),
+    INLINE_FUNC(iif,            -4, INLINEFUNC_iif,      0 ),
+    INLINE_FUNC(if,             -4, INLINEFUNC_iif,      0 ),
+  };
+#ifndef SQLITE_OMIT_ALTERTABLE
+  sqlite3AlterFunctions();
+#endif
+  sqlite3WindowFunctions();
+  sqlite3RegisterDateTimeFunctions();
+  sqlite3RegisterJsonFunctions();
+  sqlite3InsertBuiltinFuncs(aBuiltinFunc, ArraySize(aBuiltinFunc));
+
+#if 0  /* Enable to print out how the built-in functions are hashed */
+  {
+    int i;
+    FuncDef *p;
+    for(i=0; i<SQLITE_FUNC_HASH_SZ; i++){
+      printf("FUNC-HASH %02d:", i);
+      for(p=sqlite3BuiltinFunctions.a[i]; p; p=p->u.pHash){
+        int n = sqlite3Strlen30(p->zName);
+        int h = p->zName[0] + n;
+        assert( p->funcFlags & SQLITE_FUNC_BUILTIN );
+        printf(" %s(%d)", p->zName, h);
+      }
+      printf("\n");
+    }
+  }
+#endif
+}
+
+/************** End of func.c ************************************************/
+/************** Begin file fkey.c ********************************************/
+/*
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used by the compiler to add foreign key
+** support to compiled SQL statements.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+#ifndef SQLITE_OMIT_TRIGGER
+
+/*
+** Deferred and Immediate FKs
+** --------------------------
+**
+** Foreign keys in SQLite come in two flavours: deferred and immediate.
+** If an immediate foreign key constraint is violated,
+** SQLITE_CONSTRAINT_FOREIGNKEY is returned and the current
+** statement transaction rolled back. If a
+** deferred foreign key constraint is violated, no action is taken
+** immediately. However if the application attempts to commit the
+** transaction before fixing the constraint violation, the attempt fails.
+**
+** Deferred constraints are implemented using a simple counter associated
+** with the database handle. The counter is set to zero each time a
+** database transaction is opened. Each time a statement is executed
+** that causes a foreign key violation, the counter is incremented. Each
+** time a statement is executed that removes an existing violation from
+** the database, the counter is decremented. When the transaction is
+** committed, the commit fails if the current value of the counter is
+** greater than zero. This scheme has two big drawbacks:
+**
+**   * When a commit fails due to a deferred foreign key constraint,
+**     there is no way to tell which foreign constraint is not satisfied,
+**     or which row it is not satisfied for.
+**
+**   * If the database contains foreign key violations when the
+**     transaction is opened, this may cause the mechanism to malfunction.
+**
+** Despite these problems, this approach is adopted as it seems simpler
+** than the alternatives.
+**
+** INSERT operations:
+**
+**   I.1) For each FK for which the table is the child table, search
+**        the parent table for a match. If none is found increment the
+**        constraint counter.
+**
+**   I.2) For each FK for which the table is the parent table,
+**        search the child table for rows that correspond to the new
+**        row in the parent table. Decrement the counter for each row
+**        found (as the constraint is now satisfied).
+**
+** DELETE operations:
+**
+**   D.1) For each FK for which the table is the child table,
+**        search the parent table for a row that corresponds to the
+**        deleted row in the child table. If such a row is not found,
+**        decrement the counter.
+**
+**   D.2) For each FK for which the table is the parent table, search
+**        the child table for rows that correspond to the deleted row
+**        in the parent table. For each found increment the counter.
+**
+** UPDATE operations:
+**
+**   An UPDATE command requires that all 4 steps above are taken, but only
+**   for FK constraints for which the affected columns are actually
+**   modified (values must be compared at runtime).
+**
+** Note that I.1 and D.1 are very similar operations, as are I.2 and D.2.
+** This simplifies the implementation a bit.
+**
+** For the purposes of immediate FK constraints, the OR REPLACE conflict
+** resolution is considered to delete rows before the new row is inserted.
+** If a delete caused by OR REPLACE violates an FK constraint, an exception
+** is thrown, even if the FK constraint would be satisfied after the new
+** row is inserted.
+**
+** Immediate constraints are usually handled similarly. The only difference
+** is that the counter used is stored as part of each individual statement
+** object (struct Vdbe). If, after the statement has run, its immediate
+** constraint counter is greater than zero,
+** it returns SQLITE_CONSTRAINT_FOREIGNKEY
+** and the statement transaction is rolled back. An exception is an INSERT
+** statement that inserts a single row only (no triggers). In this case,
+** instead of using a counter, an exception is thrown immediately if the
+** INSERT violates a foreign key constraint. This is necessary as such
+** an INSERT does not open a statement transaction.
+**
+** TODO: How should dropping a table be handled? How should renaming a
+** table be handled?
+**
+**
+** Query API Notes
+** ---------------
+**
+** Before coding an UPDATE or DELETE row operation, the code-generator
+** for those two operations needs to know whether or not the operation
+** requires any FK processing and, if so, which columns of the original
+** row are required by the FK processing VDBE code (i.e. if FKs were
+** implemented using triggers, which of the old.* columns would be
+** accessed). No information is required by the code-generator before
+** coding an INSERT operation. The functions used by the UPDATE/DELETE
+** generation code to query for this information are:
+**
+**   sqlite3FkRequired() - Test to see if FK processing is required.
+**   sqlite3FkOldmask()  - Query for the set of required old.* columns.
+**
+**
+** Externally accessible module functions
+** --------------------------------------
+**
+**   sqlite3FkCheck()    - Check for foreign key violations.
+**   sqlite3FkActions()  - Code triggers for ON UPDATE/ON DELETE actions.
+**   sqlite3FkDelete()   - Delete an FKey structure.
+*/
+
+/*
+** VDBE Calling Convention
+** -----------------------
+**
+** Example:
+**
+**   For the following INSERT statement:
+**
+**     CREATE TABLE t1(a, b INTEGER PRIMARY KEY, c);
+**     INSERT INTO t1 VALUES(1, 2, 3.1);
+**
+**   Register (x):        2    (type integer)
+**   Register (x+1):      1    (type integer)
+**   Register (x+2):      NULL (type NULL)
+**   Register (x+3):      3.1  (type real)
+*/
+
+/*
+** A foreign key constraint requires that the key columns in the parent
+** table are collectively subject to a UNIQUE or PRIMARY KEY constraint.
+** Given that pParent is the parent table for foreign key constraint pFKey,
+** search the schema for a unique index on the parent key columns.
+**
+** If successful, zero is returned. If the parent key is an INTEGER PRIMARY
+** KEY column, then output variable *ppIdx is set to NULL. Otherwise, *ppIdx
+** is set to point to the unique index.
+**
+** If the parent key consists of a single column (the foreign key constraint
+** is not a composite foreign key), output variable *paiCol is set to NULL.
+** Otherwise, it is set to point to an allocated array of size N, where
+** N is the number of columns in the parent key. The first element of the
+** array is the index of the child table column that is mapped by the FK
+** constraint to the parent table column stored in the left-most column
+** of index *ppIdx. The second element of the array is the index of the
+** child table column that corresponds to the second left-most column of
+** *ppIdx, and so on.
+**
+** If the required index cannot be found, either because:
+**
+**   1) The named parent key columns do not exist, or
+**
+**   2) The named parent key columns do exist, but are not subject to a
+**      UNIQUE or PRIMARY KEY constraint, or
+**
+**   3) No parent key columns were provided explicitly as part of the
+**      foreign key definition, and the parent table does not have a
+**      PRIMARY KEY, or
+**
+**   4) No parent key columns were provided explicitly as part of the
+**      foreign key definition, and the PRIMARY KEY of the parent table
+**      consists of a different number of columns to the child key in
+**      the child table.
+**
+** then non-zero is returned, and a "foreign key mismatch" error loaded
+** into pParse. If an OOM error occurs, non-zero is returned and the
+** pParse->db->mallocFailed flag is set.
+*/
+SQLITE_PRIVATE int sqlite3FkLocateIndex(
+  Parse *pParse,                  /* Parse context to store any error in */
+  Table *pParent,                 /* Parent table of FK constraint pFKey */
+  FKey *pFKey,                    /* Foreign key to find index for */
+  Index **ppIdx,                  /* OUT: Unique index on parent table */
+  int **paiCol                    /* OUT: Map of index columns in pFKey */
+){
+  Index *pIdx = 0;                    /* Value to return via *ppIdx */
+  int *aiCol = 0;                     /* Value to return via *paiCol */
+  int nCol = pFKey->nCol;             /* Number of columns in parent key */
+  char *zKey = pFKey->aCol[0].zCol;   /* Name of left-most parent key column */
+
+  /* The caller is responsible for zeroing output parameters. */
+  assert( ppIdx && *ppIdx==0 );
+  assert( !paiCol || *paiCol==0 );
+  assert( pParse );
+
+  /* If this is a non-composite (single column) foreign key, check if it
+  ** maps to the INTEGER PRIMARY KEY of table pParent. If so, leave *ppIdx
+  ** and *paiCol set to zero and return early.
+  **
+  ** Otherwise, for a composite foreign key (more than one column), allocate
+  ** space for the aiCol array (returned via output parameter *paiCol).
+  ** Non-composite foreign keys do not require the aiCol array.
+  */
+  if( nCol==1 ){
+    /* The FK maps to the IPK if any of the following are true:
+    **
+    **   1) There is an INTEGER PRIMARY KEY column and the FK is implicitly
+    **      mapped to the primary key of table pParent, or
+    **   2) The FK is explicitly mapped to a column declared as INTEGER
+    **      PRIMARY KEY.
+    */
+    if( pParent->iPKey>=0 ){
+      if( !zKey ) return 0;
+      if( !sqlite3StrICmp(pParent->aCol[pParent->iPKey].zCnName, zKey) ){
+        return 0;
+      }
+    }
+  }else if( paiCol ){
+    assert( nCol>1 );
+    aiCol = (int *)sqlite3DbMallocRawNN(pParse->db, nCol*sizeof(int));
+    if( !aiCol ) return 1;
+    *paiCol = aiCol;
+  }
+
+  for(pIdx=pParent->pIndex; pIdx; pIdx=pIdx->pNext){
+    if( pIdx->nKeyCol==nCol && IsUniqueIndex(pIdx) && pIdx->pPartIdxWhere==0 ){
+      /* pIdx is a UNIQUE index (or a PRIMARY KEY) and has the right number
+      ** of columns. If each indexed column corresponds to a foreign key
+      ** column of pFKey, then this index is a winner.  */
+
+      if( zKey==0 ){
+        /* If zKey is NULL, then this foreign key is implicitly mapped to
+        ** the PRIMARY KEY of table pParent. The PRIMARY KEY index may be
+        ** identified by the test.  */
+        if( IsPrimaryKeyIndex(pIdx) ){
+          if( aiCol ){
+            int i;
+            for(i=0; i<nCol; i++) aiCol[i] = pFKey->aCol[i].iFrom;
+          }
+          break;
+        }
+      }else{
+        /* If zKey is non-NULL, then this foreign key was declared to
+        ** map to an explicit list of columns in table pParent. Check if this
+        ** index matches those columns. Also, check that the index uses
+        ** the default collation sequences for each column. */
+        int i, j;
+        for(i=0; i<nCol; i++){
+          i16 iCol = pIdx->aiColumn[i];     /* Index of column in parent tbl */
+          const char *zDfltColl;            /* Def. collation for column */
+          char *zIdxCol;                    /* Name of indexed column */
+
+          if( iCol<0 ) break; /* No foreign keys against expression indexes */
+
+          /* If the index uses a collation sequence that is different from
+          ** the default collation sequence for the column, this index is
+          ** unusable. Bail out early in this case.  */
+          zDfltColl = sqlite3ColumnColl(&pParent->aCol[iCol]);
+          if( !zDfltColl ) zDfltColl = sqlite3StrBINARY;
+          if( sqlite3StrICmp(pIdx->azColl[i], zDfltColl) ) break;
+
+          zIdxCol = pParent->aCol[iCol].zCnName;
+          for(j=0; j<nCol; j++){
+            if( sqlite3StrICmp(pFKey->aCol[j].zCol, zIdxCol)==0 ){
+              if( aiCol ) aiCol[i] = pFKey->aCol[j].iFrom;
+              break;
+            }
+          }
+          if( j==nCol ) break;
+        }
+        if( i==nCol ) break;      /* pIdx is usable */
+      }
+    }
+  }
+
+  if( !pIdx ){
+    if( !pParse->disableTriggers ){
+      sqlite3ErrorMsg(pParse,
+           "foreign key mismatch - \"%w\" referencing \"%w\"",
+           pFKey->pFrom->zName, pFKey->zTo);
+    }
+    sqlite3DbFree(pParse->db, aiCol);
+    return 1;
+  }
+
+  *ppIdx = pIdx;
+  return 0;
+}
+
+/*
+** This function is called when a row is inserted into or deleted from the
+** child table of foreign key constraint pFKey. If an SQL UPDATE is executed
+** on the child table of pFKey, this function is invoked twice for each row
+** affected - once to "delete" the old row, and then again to "insert" the
+** new row.
+**
+** Each time it is called, this function generates VDBE code to locate the
+** row in the parent table that corresponds to the row being inserted into
+** or deleted from the child table. If the parent row can be found, no
+** special action is taken. Otherwise, if the parent row can *not* be
+** found in the parent table:
+**
+**   Operation | FK type   | Action taken
+**   --------------------------------------------------------------------------
+**   INSERT      immediate   Increment the "immediate constraint counter".
+**
+**   DELETE      immediate   Decrement the "immediate constraint counter".
+**
+**   INSERT      deferred    Increment the "deferred constraint counter".
+**
+**   DELETE      deferred    Decrement the "deferred constraint counter".
+**
+** These operations are identified in the comment at the top of this file
+** (fkey.c) as "I.1" and "D.1".
+*/
+static void fkLookupParent(
+  Parse *pParse,        /* Parse context */
+  int iDb,              /* Index of database housing pTab */
+  Table *pTab,          /* Parent table of FK pFKey */
+  Index *pIdx,          /* Unique index on parent key columns in pTab */
+  FKey *pFKey,          /* Foreign key constraint */
+  int *aiCol,           /* Map from parent key columns to child table columns */
+  int regData,          /* Address of array containing child table row */
+  int nIncr,            /* Increment constraint counter by this */
+  int isIgnore          /* If true, pretend pTab contains all NULL values */
+){
+  int i;                                    /* Iterator variable */
+  Vdbe *v = sqlite3GetVdbe(pParse);         /* Vdbe to add code to */
+  int iCur = pParse->nTab - 1;              /* Cursor number to use */
+  int iOk = sqlite3VdbeMakeLabel(pParse);   /* jump here if parent key found */
+
+  sqlite3VdbeVerifyAbortable(v,
+    (!pFKey->isDeferred
+      && !(pParse->db->flags & SQLITE_DeferFKs)
+      && !pParse->pToplevel
+      && !pParse->isMultiWrite) ? OE_Abort : OE_Ignore);
+
+  /* If nIncr is less than zero, then check at runtime if there are any
+  ** outstanding constraints to resolve. If there are not, there is no need
+  ** to check if deleting this row resolves any outstanding violations.
+  **
+  ** Check if any of the key columns in the child table row are NULL. If
+  ** any are, then the constraint is considered satisfied. No need to
+  ** search for a matching row in the parent table.  */
+  if( nIncr<0 ){
+    sqlite3VdbeAddOp2(v, OP_FkIfZero, pFKey->isDeferred, iOk);
+    VdbeCoverage(v);
+  }
+  for(i=0; i<pFKey->nCol; i++){
+    int iReg = sqlite3TableColumnToStorage(pFKey->pFrom,aiCol[i]) + regData + 1;
+    sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iOk); VdbeCoverage(v);
+  }
+
+  if( isIgnore==0 ){
+    if( pIdx==0 ){
+      /* If pIdx is NULL, then the parent key is the INTEGER PRIMARY KEY
+      ** column of the parent table (table pTab).  */
+      int iMustBeInt;               /* Address of MustBeInt instruction */
+      int regTemp = sqlite3GetTempReg(pParse);
+
+      /* Invoke MustBeInt to coerce the child key value to an integer (i.e.
+      ** apply the affinity of the parent key). If this fails, then there
+      ** is no matching parent key. Before using MustBeInt, make a copy of
+      ** the value. Otherwise, the value inserted into the child key column
+      ** will have INTEGER affinity applied to it, which may not be correct.  */
+      sqlite3VdbeAddOp2(v, OP_SCopy,
+        sqlite3TableColumnToStorage(pFKey->pFrom,aiCol[0])+1+regData, regTemp);
+      iMustBeInt = sqlite3VdbeAddOp2(v, OP_MustBeInt, regTemp, 0);
+      VdbeCoverage(v);
+
+      /* If the parent table is the same as the child table, and we are about
+      ** to increment the constraint-counter (i.e. this is an INSERT operation),
+      ** then check if the row being inserted matches itself. If so, do not
+      ** increment the constraint-counter.  */
+      if( pTab==pFKey->pFrom && nIncr==1 ){
+        sqlite3VdbeAddOp3(v, OP_Eq, regData, iOk, regTemp); VdbeCoverage(v);
+        sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+      }
+
+      sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
+      sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regTemp); VdbeCoverage(v);
+      sqlite3VdbeGoto(v, iOk);
+      sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
+      sqlite3VdbeJumpHere(v, iMustBeInt);
+      sqlite3ReleaseTempReg(pParse, regTemp);
+    }else{
+      int nCol = pFKey->nCol;
+      int regTemp = sqlite3GetTempRange(pParse, nCol);
+
+      sqlite3VdbeAddOp3(v, OP_OpenRead, iCur, pIdx->tnum, iDb);
+      sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+      for(i=0; i<nCol; i++){
+        sqlite3VdbeAddOp2(v, OP_Copy,
+               sqlite3TableColumnToStorage(pFKey->pFrom, aiCol[i])+1+regData,
+               regTemp+i);
+      }
+
+      /* If the parent table is the same as the child table, and we are about
+      ** to increment the constraint-counter (i.e. this is an INSERT operation),
+      ** then check if the row being inserted matches itself. If so, do not
+      ** increment the constraint-counter.
+      **
+      ** If any of the parent-key values are NULL, then the row cannot match
+      ** itself. So set JUMPIFNULL to make sure we do the OP_Found if any
+      ** of the parent-key values are NULL (at this point it is known that
+      ** none of the child key values are).
+      */
+      if( pTab==pFKey->pFrom && nIncr==1 ){
+        int iJump = sqlite3VdbeCurrentAddr(v) + nCol + 1;
+        for(i=0; i<nCol; i++){
+          int iChild = sqlite3TableColumnToStorage(pFKey->pFrom,aiCol[i])
+                              +1+regData;
+          int iParent = 1+regData;
+          iParent += sqlite3TableColumnToStorage(pIdx->pTable,
+                                                 pIdx->aiColumn[i]);
+          assert( pIdx->aiColumn[i]>=0 );
+          assert( aiCol[i]!=pTab->iPKey );
+          if( pIdx->aiColumn[i]==pTab->iPKey ){
+            /* The parent key is a composite key that includes the IPK column */
+            iParent = regData;
+          }
+          sqlite3VdbeAddOp3(v, OP_Ne, iChild, iJump, iParent); VdbeCoverage(v);
+          sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
+        }
+        sqlite3VdbeGoto(v, iOk);
+      }
+
+      sqlite3VdbeAddOp4(v, OP_Affinity, regTemp, nCol, 0,
+                        sqlite3IndexAffinityStr(pParse->db,pIdx), nCol);
+      sqlite3VdbeAddOp4Int(v, OP_Found, iCur, iOk, regTemp, nCol);
+      VdbeCoverage(v);
+      sqlite3ReleaseTempRange(pParse, regTemp, nCol);
+    }
+  }
+
+  if( !pFKey->isDeferred && !(pParse->db->flags & SQLITE_DeferFKs)
+   && !pParse->pToplevel
+   && !pParse->isMultiWrite
+  ){
+    /* Special case: If this is an INSERT statement that will insert exactly
+    ** one row into the table, raise a constraint immediately instead of
+    ** incrementing a counter. This is necessary as the VM code is being
+    ** generated for will not open a statement transaction.  */
+    assert( nIncr==1 );
+    sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_FOREIGNKEY,
+        OE_Abort, 0, P4_STATIC, P5_ConstraintFK);
+  }else{
+    if( nIncr>0 && pFKey->isDeferred==0 ){
+      sqlite3MayAbort(pParse);
+    }
+    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
+  }
+
+  sqlite3VdbeResolveLabel(v, iOk);
+  sqlite3VdbeAddOp1(v, OP_Close, iCur);
+}
+
+
+/*
+** Return an Expr object that refers to a memory register corresponding
+** to column iCol of table pTab.
+**
+** regBase is the first of an array of register that contains the data
+** for pTab.  regBase itself holds the rowid.  regBase+1 holds the first
+** column.  regBase+2 holds the second column, and so forth.
+*/
+static Expr *exprTableRegister(
+  Parse *pParse,     /* Parsing and code generating context */
+  Table *pTab,       /* The table whose content is at r[regBase]... */
+  int regBase,       /* Contents of table pTab */
+  i16 iCol           /* Which column of pTab is desired */
+){
+  Expr *pExpr;
+  Column *pCol;
+  const char *zColl;
+  sqlite3 *db = pParse->db;
+
+  pExpr = sqlite3Expr(db, TK_REGISTER, 0);
+  if( pExpr ){
+    if( iCol>=0 && iCol!=pTab->iPKey ){
+      pCol = &pTab->aCol[iCol];
+      pExpr->iTable = regBase + sqlite3TableColumnToStorage(pTab,iCol) + 1;
+      pExpr->affExpr = pCol->affinity;
+      zColl = sqlite3ColumnColl(pCol);
+      if( zColl==0 ) zColl = db->pDfltColl->zName;
+      pExpr = sqlite3ExprAddCollateString(pParse, pExpr, zColl);
+    }else{
+      pExpr->iTable = regBase;
+      pExpr->affExpr = SQLITE_AFF_INTEGER;
+    }
+  }
+  return pExpr;
+}
+
+/*
+** Return an Expr object that refers to column iCol of table pTab which
+** has cursor iCur.
+*/
+static Expr *exprTableColumn(
+  sqlite3 *db,      /* The database connection */
+  Table *pTab,      /* The table whose column is desired */
+  int iCursor,      /* The open cursor on the table */
+  i16 iCol          /* The column that is wanted */
+){
+  Expr *pExpr = sqlite3Expr(db, TK_COLUMN, 0);
+  if( pExpr ){
+    assert( ExprUseYTab(pExpr) );
+    pExpr->y.pTab = pTab;
+    pExpr->iTable = iCursor;
+    pExpr->iColumn = iCol;
+  }
+  return pExpr;
+}
+
+/*
+** This function is called to generate code executed when a row is deleted
+** from the parent table of foreign key constraint pFKey and, if pFKey is
+** deferred, when a row is inserted into the same table. When generating
+** code for an SQL UPDATE operation, this function may be called twice -
+** once to "delete" the old row and once to "insert" the new row.
+**
+** Parameter nIncr is passed -1 when inserting a row (as this may decrease
+** the number of FK violations in the db) or +1 when deleting one (as this
+** may increase the number of FK constraint problems).
+**
+** The code generated by this function scans through the rows in the child
+** table that correspond to the parent table row being deleted or inserted.
+** For each child row found, one of the following actions is taken:
+**
+**   Operation | FK type   | Action taken
+**   --------------------------------------------------------------------------
+**   DELETE      immediate   Increment the "immediate constraint counter".
+**
+**   INSERT      immediate   Decrement the "immediate constraint counter".
+**
+**   DELETE      deferred    Increment the "deferred constraint counter".
+**
+**   INSERT      deferred    Decrement the "deferred constraint counter".
+**
+** These operations are identified in the comment at the top of this file
+** (fkey.c) as "I.2" and "D.2".
+*/
+static void fkScanChildren(
+  Parse *pParse,                  /* Parse context */
+  SrcList *pSrc,                  /* The child table to be scanned */
+  Table *pTab,                    /* The parent table */
+  Index *pIdx,                    /* Index on parent covering the foreign key */
+  FKey *pFKey,                    /* The foreign key linking pSrc to pTab */
+  int *aiCol,                     /* Map from pIdx cols to child table cols */
+  int regData,                    /* Parent row data starts here */
+  int nIncr                       /* Amount to increment deferred counter by */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  int i;                          /* Iterator variable */
+  Expr *pWhere = 0;               /* WHERE clause to scan with */
+  NameContext sNameContext;       /* Context used to resolve WHERE clause */
+  WhereInfo *pWInfo;              /* Context used by sqlite3WhereXXX() */
+  int iFkIfZero = 0;              /* Address of OP_FkIfZero */
+  Vdbe *v = sqlite3GetVdbe(pParse);
+
+  assert( pIdx==0 || pIdx->pTable==pTab );
+  assert( pIdx==0 || pIdx->nKeyCol==pFKey->nCol );
+  assert( pIdx!=0 || pFKey->nCol==1 );
+  assert( pIdx!=0 || HasRowid(pTab) );
+
+  if( nIncr<0 ){
+    iFkIfZero = sqlite3VdbeAddOp2(v, OP_FkIfZero, pFKey->isDeferred, 0);
+    VdbeCoverage(v);
+  }
+
+  /* Create an Expr object representing an SQL expression like:
+  **
+  **   <parent-key1> = <child-key1> AND <parent-key2> = <child-key2> ...
+  **
+  ** The collation sequence used for the comparison should be that of
+  ** the parent key columns. The affinity of the parent key column should
+  ** be applied to each child key value before the comparison takes place.
+  */
+  for(i=0; i<pFKey->nCol; i++){
+    Expr *pLeft;                  /* Value from parent table row */
+    Expr *pRight;                 /* Column ref to child table */
+    Expr *pEq;                    /* Expression (pLeft = pRight) */
+    i16 iCol;                     /* Index of column in child table */
+    const char *zCol;             /* Name of column in child table */
+
+    iCol = pIdx ? pIdx->aiColumn[i] : -1;
+    pLeft = exprTableRegister(pParse, pTab, regData, iCol);
+    iCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
+    assert( iCol>=0 );
+    zCol = pFKey->pFrom->aCol[iCol].zCnName;
+    pRight = sqlite3Expr(db, TK_ID, zCol);
+    pEq = sqlite3PExpr(pParse, TK_EQ, pLeft, pRight);
+    pWhere = sqlite3ExprAnd(pParse, pWhere, pEq);
+  }
+
+  /* If the child table is the same as the parent table, then add terms
+  ** to the WHERE clause that prevent this entry from being scanned.
+  ** The added WHERE clause terms are like this:
+  **
+  **     $current_rowid!=rowid
+  **     NOT( $current_a==a AND $current_b==b AND ... )
+  **
+  ** The first form is used for rowid tables.  The second form is used
+  ** for WITHOUT ROWID tables. In the second form, the *parent* key is
+  ** (a,b,...). Either the parent or primary key could be used to
+  ** uniquely identify the current row, but the parent key is more convenient
+  ** as the required values have already been loaded into registers
+  ** by the caller.
+  */
+  if( pTab==pFKey->pFrom && nIncr>0 ){
+    Expr *pNe;                    /* Expression (pLeft != pRight) */
+    Expr *pLeft;                  /* Value from parent table row */
+    Expr *pRight;                 /* Column ref to child table */
+    if( HasRowid(pTab) ){
+      pLeft = exprTableRegister(pParse, pTab, regData, -1);
+      pRight = exprTableColumn(db, pTab, pSrc->a[0].iCursor, -1);
+      pNe = sqlite3PExpr(pParse, TK_NE, pLeft, pRight);
+    }else{
+      Expr *pEq, *pAll = 0;
+      assert( pIdx!=0 );
+      for(i=0; i<pIdx->nKeyCol; i++){
+        i16 iCol = pIdx->aiColumn[i];
+        assert( iCol>=0 );
+        pLeft = exprTableRegister(pParse, pTab, regData, iCol);
+        pRight = sqlite3Expr(db, TK_ID, pTab->aCol[iCol].zCnName);
+        pEq = sqlite3PExpr(pParse, TK_IS, pLeft, pRight);
+        pAll = sqlite3ExprAnd(pParse, pAll, pEq);
+      }
+      pNe = sqlite3PExpr(pParse, TK_NOT, pAll, 0);
+    }
+    pWhere = sqlite3ExprAnd(pParse, pWhere, pNe);
+  }
+
+  /* Resolve the references in the WHERE clause. */
+  memset(&sNameContext, 0, sizeof(NameContext));
+  sNameContext.pSrcList = pSrc;
+  sNameContext.pParse = pParse;
+  sqlite3ResolveExprNames(&sNameContext, pWhere);
+
+  /* Create VDBE to loop through the entries in pSrc that match the WHERE
+  ** clause. For each row found, increment either the deferred or immediate
+  ** foreign key constraint counter. */
+  if( pParse->nErr==0 ){
+    pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0, 0);
+    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
+    if( pWInfo ){
+      sqlite3WhereEnd(pWInfo);
+    }
+  }
+
+  /* Clean up the WHERE clause constructed above. */
+  sqlite3ExprDelete(db, pWhere);
+  if( iFkIfZero ){
+    sqlite3VdbeJumpHereOrPopInst(v, iFkIfZero);
+  }
+}
+
+/*
+** This function returns a linked list of FKey objects (connected by
+** FKey.pNextTo) holding all children of table pTab.  For example,
+** given the following schema:
+**
+**   CREATE TABLE t1(a PRIMARY KEY);
+**   CREATE TABLE t2(b REFERENCES t1(a);
+**
+** Calling this function with table "t1" as an argument returns a pointer
+** to the FKey structure representing the foreign key constraint on table
+** "t2". Calling this function with "t2" as the argument would return a
+** NULL pointer (as there are no FK constraints for which t2 is the parent
+** table).
+*/
+SQLITE_PRIVATE FKey *sqlite3FkReferences(Table *pTab){
+  return (FKey *)sqlite3HashFind(&pTab->pSchema->fkeyHash, pTab->zName);
+}
+
+/*
+** The second argument is a Trigger structure allocated by the
+** fkActionTrigger() routine. This function deletes the Trigger structure
+** and all of its sub-components.
+**
+** The Trigger structure or any of its sub-components may be allocated from
+** the lookaside buffer belonging to database handle dbMem.
+*/
+static void fkTriggerDelete(sqlite3 *dbMem, Trigger *p){
+  if( p ){
+    TriggerStep *pStep = p->step_list;
+    sqlite3ExprDelete(dbMem, pStep->pWhere);
+    sqlite3ExprListDelete(dbMem, pStep->pExprList);
+    sqlite3SelectDelete(dbMem, pStep->pSelect);
+    sqlite3ExprDelete(dbMem, p->pWhen);
+    sqlite3DbFree(dbMem, p);
+  }
+}
+
+/*
+** Clear the apTrigger[] cache of CASCADE triggers for all foreign keys
+** in a particular database.  This needs to happen when the schema
+** changes.
+*/
+SQLITE_PRIVATE void sqlite3FkClearTriggerCache(sqlite3 *db, int iDb){
+  HashElem *k;
+  Hash *pHash = &db->aDb[iDb].pSchema->tblHash;
+  for(k=sqliteHashFirst(pHash); k; k=sqliteHashNext(k)){
+    Table *pTab = sqliteHashData(k);
+    FKey *pFKey;
+    if( !IsOrdinaryTable(pTab) ) continue;
+    for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+      fkTriggerDelete(db, pFKey->apTrigger[0]); pFKey->apTrigger[0] = 0;
+      fkTriggerDelete(db, pFKey->apTrigger[1]); pFKey->apTrigger[1] = 0;
+    }
+  }
+}
+
+/*
+** This function is called to generate code that runs when table pTab is
+** being dropped from the database. The SrcList passed as the second argument
+** to this function contains a single entry guaranteed to resolve to
+** table pTab.
+**
+** Normally, no code is required. However, if either
+**
+**   (a) The table is the parent table of a FK constraint, or
+**   (b) The table is the child table of a deferred FK constraint and it is
+**       determined at runtime that there are outstanding deferred FK
+**       constraint violations in the database,
+**
+** then the equivalent of "DELETE FROM <tbl>" is executed before dropping
+** the table from the database. Triggers are disabled while running this
+** DELETE, but foreign key actions are not.
+*/
+SQLITE_PRIVATE void sqlite3FkDropTable(Parse *pParse, SrcList *pName, Table *pTab){
+  sqlite3 *db = pParse->db;
+  if( (db->flags&SQLITE_ForeignKeys) && IsOrdinaryTable(pTab) ){
+    int iSkip = 0;
+    Vdbe *v = sqlite3GetVdbe(pParse);
+
+    assert( v );                  /* VDBE has already been allocated */
+    assert( IsOrdinaryTable(pTab) );
+    if( sqlite3FkReferences(pTab)==0 ){
+      /* Search for a deferred foreign key constraint for which this table
+      ** is the child table. If one cannot be found, return without
+      ** generating any VDBE code. If one can be found, then jump over
+      ** the entire DELETE if there are no outstanding deferred constraints
+      ** when this statement is run.  */
+      FKey *p;
+      for(p=pTab->u.tab.pFKey; p; p=p->pNextFrom){
+        if( p->isDeferred || (db->flags & SQLITE_DeferFKs) ) break;
+      }
+      if( !p ) return;
+      iSkip = sqlite3VdbeMakeLabel(pParse);
+      sqlite3VdbeAddOp2(v, OP_FkIfZero, 1, iSkip); VdbeCoverage(v);
+    }
+
+    pParse->disableTriggers = 1;
+    sqlite3DeleteFrom(pParse, sqlite3SrcListDup(db, pName, 0), 0, 0, 0);
+    pParse->disableTriggers = 0;
+
+    /* If the DELETE has generated immediate foreign key constraint
+    ** violations, halt the VDBE and return an error at this point, before
+    ** any modifications to the schema are made. This is because statement
+    ** transactions are not able to rollback schema changes.
+    **
+    ** If the SQLITE_DeferFKs flag is set, then this is not required, as
+    ** the statement transaction will not be rolled back even if FK
+    ** constraints are violated.
+    */
+    if( (db->flags & SQLITE_DeferFKs)==0 ){
+      sqlite3VdbeVerifyAbortable(v, OE_Abort);
+      sqlite3VdbeAddOp2(v, OP_FkIfZero, 0, sqlite3VdbeCurrentAddr(v)+2);
+      VdbeCoverage(v);
+      sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_FOREIGNKEY,
+          OE_Abort, 0, P4_STATIC, P5_ConstraintFK);
+    }
+
+    if( iSkip ){
+      sqlite3VdbeResolveLabel(v, iSkip);
+    }
+  }
+}
+
+
+/*
+** The second argument points to an FKey object representing a foreign key
+** for which pTab is the child table. An UPDATE statement against pTab
+** is currently being processed. For each column of the table that is
+** actually updated, the corresponding element in the aChange[] array
+** is zero or greater (if a column is unmodified the corresponding element
+** is set to -1). If the rowid column is modified by the UPDATE statement
+** the bChngRowid argument is non-zero.
+**
+** This function returns true if any of the columns that are part of the
+** child key for FK constraint *p are modified.
+*/
+static int fkChildIsModified(
+  Table *pTab,                    /* Table being updated */
+  FKey *p,                        /* Foreign key for which pTab is the child */
+  int *aChange,                   /* Array indicating modified columns */
+  int bChngRowid                  /* True if rowid is modified by this update */
+){
+  int i;
+  for(i=0; i<p->nCol; i++){
+    int iChildKey = p->aCol[i].iFrom;
+    if( aChange[iChildKey]>=0 ) return 1;
+    if( iChildKey==pTab->iPKey && bChngRowid ) return 1;
+  }
+  return 0;
+}
+
+/*
+** The second argument points to an FKey object representing a foreign key
+** for which pTab is the parent table. An UPDATE statement against pTab
+** is currently being processed. For each column of the table that is
+** actually updated, the corresponding element in the aChange[] array
+** is zero or greater (if a column is unmodified the corresponding element
+** is set to -1). If the rowid column is modified by the UPDATE statement
+** the bChngRowid argument is non-zero.
+**
+** This function returns true if any of the columns that are part of the
+** parent key for FK constraint *p are modified.
+*/
+static int fkParentIsModified(
+  Table *pTab,
+  FKey *p,
+  int *aChange,
+  int bChngRowid
+){
+  int i;
+  for(i=0; i<p->nCol; i++){
+    char *zKey = p->aCol[i].zCol;
+    int iKey;
+    for(iKey=0; iKey<pTab->nCol; iKey++){
+      if( aChange[iKey]>=0 || (iKey==pTab->iPKey && bChngRowid) ){
+        Column *pCol = &pTab->aCol[iKey];
+        if( zKey ){
+          if( 0==sqlite3StrICmp(pCol->zCnName, zKey) ) return 1;
+        }else if( pCol->colFlags & COLFLAG_PRIMKEY ){
+          return 1;
+        }
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Return true if the parser passed as the first argument is being
+** used to code a trigger that is really a "SET NULL" action belonging
+** to trigger pFKey.
+*/
+static int isSetNullAction(Parse *pParse, FKey *pFKey){
+  Parse *pTop = sqlite3ParseToplevel(pParse);
+  if( pTop->pTriggerPrg ){
+    Trigger *p = pTop->pTriggerPrg->pTrigger;
+    if( (p==pFKey->apTrigger[0] && pFKey->aAction[0]==OE_SetNull)
+     || (p==pFKey->apTrigger[1] && pFKey->aAction[1]==OE_SetNull)
+    ){
+      assert( (pTop->db->flags & SQLITE_FkNoAction)==0 );
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** This function is called when inserting, deleting or updating a row of
+** table pTab to generate VDBE code to perform foreign key constraint
+** processing for the operation.
+**
+** For a DELETE operation, parameter regOld is passed the index of the
+** first register in an array of (pTab->nCol+1) registers containing the
+** rowid of the row being deleted, followed by each of the column values
+** of the row being deleted, from left to right. Parameter regNew is passed
+** zero in this case.
+**
+** For an INSERT operation, regOld is passed zero and regNew is passed the
+** first register of an array of (pTab->nCol+1) registers containing the new
+** row data.
+**
+** For an UPDATE operation, this function is called twice. Once before
+** the original record is deleted from the table using the calling convention
+** described for DELETE. Then again after the original record is deleted
+** but before the new record is inserted using the INSERT convention.
+*/
+SQLITE_PRIVATE void sqlite3FkCheck(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Row is being deleted from this table */
+  int regOld,                     /* Previous row data is stored here */
+  int regNew,                     /* New row data is stored here */
+  int *aChange,                   /* Array indicating UPDATEd columns (or 0) */
+  int bChngRowid                  /* True if rowid is UPDATEd */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  FKey *pFKey;                    /* Used to iterate through FKs */
+  int iDb;                        /* Index of database containing pTab */
+  const char *zDb;                /* Name of database containing pTab */
+  int isIgnoreErrors = pParse->disableTriggers;
+
+  /* Exactly one of regOld and regNew should be non-zero. */
+  assert( (regOld==0)!=(regNew==0) );
+
+  /* If foreign-keys are disabled, this function is a no-op. */
+  if( (db->flags&SQLITE_ForeignKeys)==0 ) return;
+  if( !IsOrdinaryTable(pTab) ) return;
+
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  zDb = db->aDb[iDb].zDbSName;
+
+  /* Loop through all the foreign key constraints for which pTab is the
+  ** child table (the table that the foreign key definition is part of).  */
+  for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+    Table *pTo;                   /* Parent table of foreign key pFKey */
+    Index *pIdx = 0;              /* Index on key columns in pTo */
+    int *aiFree = 0;
+    int *aiCol;
+    int iCol;
+    int i;
+    int bIgnore = 0;
+
+    if( aChange
+     && sqlite3_stricmp(pTab->zName, pFKey->zTo)!=0
+     && fkChildIsModified(pTab, pFKey, aChange, bChngRowid)==0
+    ){
+      continue;
+    }
+
+    /* Find the parent table of this foreign key. Also find a unique index
+    ** on the parent key columns in the parent table. If either of these
+    ** schema items cannot be located, set an error in pParse and return
+    ** early.  */
+    if( pParse->disableTriggers ){
+      pTo = sqlite3FindTable(db, pFKey->zTo, zDb);
+    }else{
+      pTo = sqlite3LocateTable(pParse, 0, pFKey->zTo, zDb);
+    }
+    if( !pTo || sqlite3FkLocateIndex(pParse, pTo, pFKey, &pIdx, &aiFree) ){
+      assert( isIgnoreErrors==0 || (regOld!=0 && regNew==0) );
+      if( !isIgnoreErrors || db->mallocFailed ) return;
+      if( pTo==0 ){
+        /* If isIgnoreErrors is true, then a table is being dropped. In this
+        ** case SQLite runs a "DELETE FROM xxx" on the table being dropped
+        ** before actually dropping it in order to check FK constraints.
+        ** If the parent table of an FK constraint on the current table is
+        ** missing, behave as if it is empty. i.e. decrement the relevant
+        ** FK counter for each row of the current table with non-NULL keys.
+        */
+        Vdbe *v = sqlite3GetVdbe(pParse);
+        int iJump = sqlite3VdbeCurrentAddr(v) + pFKey->nCol + 1;
+        for(i=0; i<pFKey->nCol; i++){
+          int iFromCol, iReg;
+          iFromCol = pFKey->aCol[i].iFrom;
+          iReg = sqlite3TableColumnToStorage(pFKey->pFrom,iFromCol) + regOld+1;
+          sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iJump); VdbeCoverage(v);
+        }
+        sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, -1);
+      }
+      continue;
+    }
+    assert( pFKey->nCol==1 || (aiFree && pIdx) );
+
+    if( aiFree ){
+      aiCol = aiFree;
+    }else{
+      iCol = pFKey->aCol[0].iFrom;
+      aiCol = &iCol;
+    }
+    for(i=0; i<pFKey->nCol; i++){
+      if( aiCol[i]==pTab->iPKey ){
+        aiCol[i] = -1;
+      }
+      assert( pIdx==0 || pIdx->aiColumn[i]>=0 );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+      /* Request permission to read the parent key columns. If the
+      ** authorization callback returns SQLITE_IGNORE, behave as if any
+      ** values read from the parent table are NULL. */
+      if( db->xAuth ){
+        int rcauth;
+        char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zCnName;
+        rcauth = sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb);
+        bIgnore = (rcauth==SQLITE_IGNORE);
+      }
+#endif
+    }
+
+    /* Take a shared-cache advisory read-lock on the parent table. Allocate
+    ** a cursor to use to search the unique index on the parent key columns
+    ** in the parent table.  */
+    sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
+    pParse->nTab++;
+
+    if( regOld!=0 ){
+      /* A row is being removed from the child table. Search for the parent.
+      ** If the parent does not exist, removing the child row resolves an
+      ** outstanding foreign key constraint violation. */
+      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1, bIgnore);
+    }
+    if( regNew!=0 && !isSetNullAction(pParse, pFKey) ){
+      /* A row is being added to the child table. If a parent row cannot
+      ** be found, adding the child row has violated the FK constraint.
+      **
+      ** If this operation is being performed as part of a trigger program
+      ** that is actually a "SET NULL" action belonging to this very
+      ** foreign key, then omit this scan altogether. As all child key
+      ** values are guaranteed to be NULL, it is not possible for adding
+      ** this row to cause an FK violation.  */
+      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1, bIgnore);
+    }
+
+    sqlite3DbFree(db, aiFree);
+  }
+
+  /* Loop through all the foreign key constraints that refer to this table.
+  ** (the "child" constraints) */
+  for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
+    Index *pIdx = 0;              /* Foreign key index for pFKey */
+    SrcList *pSrc;
+    int *aiCol = 0;
+
+    if( aChange && fkParentIsModified(pTab, pFKey, aChange, bChngRowid)==0 ){
+      continue;
+    }
+
+    if( !pFKey->isDeferred && !(db->flags & SQLITE_DeferFKs)
+     && !pParse->pToplevel && !pParse->isMultiWrite
+    ){
+      assert( regOld==0 && regNew!=0 );
+      /* Inserting a single row into a parent table cannot cause (or fix)
+      ** an immediate foreign key violation. So do nothing in this case.  */
+      continue;
+    }
+
+    if( sqlite3FkLocateIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ){
+      if( !isIgnoreErrors || db->mallocFailed ) return;
+      continue;
+    }
+    assert( aiCol || pFKey->nCol==1 );
+
+    /* Create a SrcList structure containing the child table.  We need the
+    ** child table as a SrcList for sqlite3WhereBegin() */
+    pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
+    if( pSrc ){
+      SrcItem *pItem = pSrc->a;
+      pItem->pSTab = pFKey->pFrom;
+      pItem->zName = pFKey->pFrom->zName;
+      pItem->pSTab->nTabRef++;
+      pItem->iCursor = pParse->nTab++;
+
+      if( regNew!=0 ){
+        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regNew, -1);
+      }
+      if( regOld!=0 ){
+        int eAction = pFKey->aAction[aChange!=0];
+        if( (db->flags & SQLITE_FkNoAction) ) eAction = OE_None;
+
+        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regOld, 1);
+        /* If this is a deferred FK constraint, or a CASCADE or SET NULL
+        ** action applies, then any foreign key violations caused by
+        ** removing the parent key will be rectified by the action trigger.
+        ** So do not set the "may-abort" flag in this case.
+        **
+        ** Note 1: If the FK is declared "ON UPDATE CASCADE", then the
+        ** may-abort flag will eventually be set on this statement anyway
+        ** (when this function is called as part of processing the UPDATE
+        ** within the action trigger).
+        **
+        ** Note 2: At first glance it may seem like SQLite could simply omit
+        ** all OP_FkCounter related scans when either CASCADE or SET NULL
+        ** applies. The trouble starts if the CASCADE or SET NULL action
+        ** trigger causes other triggers or action rules attached to the
+        ** child table to fire. In these cases the fk constraint counters
+        ** might be set incorrectly if any OP_FkCounter related scans are
+        ** omitted.  */
+        if( !pFKey->isDeferred && eAction!=OE_Cascade && eAction!=OE_SetNull ){
+          sqlite3MayAbort(pParse);
+        }
+      }
+      pItem->zName = 0;
+      sqlite3SrcListDelete(db, pSrc);
+    }
+    sqlite3DbFree(db, aiCol);
+  }
+}
+
+#define COLUMN_MASK(x) (((x)>31) ? 0xffffffff : ((u32)1<<(x)))
+
+/*
+** This function is called before generating code to update or delete a
+** row contained in table pTab.
+*/
+SQLITE_PRIVATE u32 sqlite3FkOldmask(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab                     /* Table being modified */
+){
+  u32 mask = 0;
+  if( pParse->db->flags&SQLITE_ForeignKeys && IsOrdinaryTable(pTab) ){
+    FKey *p;
+    int i;
+    for(p=pTab->u.tab.pFKey; p; p=p->pNextFrom){
+      for(i=0; i<p->nCol; i++) mask |= COLUMN_MASK(p->aCol[i].iFrom);
+    }
+    for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
+      Index *pIdx = 0;
+      sqlite3FkLocateIndex(pParse, pTab, p, &pIdx, 0);
+      if( pIdx ){
+        for(i=0; i<pIdx->nKeyCol; i++){
+          assert( pIdx->aiColumn[i]>=0 );
+          mask |= COLUMN_MASK(pIdx->aiColumn[i]);
+        }
+      }
+    }
+  }
+  return mask;
+}
+
+
+/*
+** This function is called before generating code to update or delete a
+** row contained in table pTab. If the operation is a DELETE, then
+** parameter aChange is passed a NULL value. For an UPDATE, aChange points
+** to an array of size N, where N is the number of columns in table pTab.
+** If the i'th column is not modified by the UPDATE, then the corresponding
+** entry in the aChange[] array is set to -1. If the column is modified,
+** the value is 0 or greater. Parameter chngRowid is set to true if the
+** UPDATE statement modifies the rowid fields of the table.
+**
+** If any foreign key processing will be required, this function returns
+** non-zero. If there is no foreign key related processing, this function
+** returns zero.
+**
+** For an UPDATE, this function returns 2 if:
+**
+**   * There are any FKs for which pTab is the child and the parent table
+**     and any FK processing at all is required (even of a different FK), or
+**
+**   * the UPDATE modifies one or more parent keys for which the action is
+**     not "NO ACTION" (i.e. is CASCADE, SET DEFAULT or SET NULL).
+**
+** Or, assuming some other foreign key processing is required, 1.
+*/
+SQLITE_PRIVATE int sqlite3FkRequired(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being modified */
+  int *aChange,                   /* Non-NULL for UPDATE operations */
+  int chngRowid                   /* True for UPDATE that affects rowid */
+){
+  int eRet = 1;                   /* Value to return if bHaveFK is true */
+  int bHaveFK = 0;                /* If FK processing is required */
+  if( pParse->db->flags&SQLITE_ForeignKeys && IsOrdinaryTable(pTab) ){
+    if( !aChange ){
+      /* A DELETE operation. Foreign key processing is required if the
+      ** table in question is either the child or parent table for any
+      ** foreign key constraint.  */
+      bHaveFK = (sqlite3FkReferences(pTab) || pTab->u.tab.pFKey);
+    }else{
+      /* This is an UPDATE. Foreign key processing is only required if the
+      ** operation modifies one or more child or parent key columns. */
+      FKey *p;
+
+      /* Check if any child key columns are being modified. */
+      for(p=pTab->u.tab.pFKey; p; p=p->pNextFrom){
+        if( fkChildIsModified(pTab, p, aChange, chngRowid) ){
+          if( 0==sqlite3_stricmp(pTab->zName, p->zTo) ) eRet = 2;
+          bHaveFK = 1;
+        }
+      }
+
+      /* Check if any parent key columns are being modified. */
+      for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
+        if( fkParentIsModified(pTab, p, aChange, chngRowid) ){
+          if( (pParse->db->flags & SQLITE_FkNoAction)==0
+           && p->aAction[1]!=OE_None
+          ){
+            return 2;
+          }
+          bHaveFK = 1;
+        }
+      }
+    }
+  }
+  return bHaveFK ? eRet : 0;
+}
+
+/*
+** This function is called when an UPDATE or DELETE operation is being
+** compiled on table pTab, which is the parent table of foreign-key pFKey.
+** If the current operation is an UPDATE, then the pChanges parameter is
+** passed a pointer to the list of columns being modified. If it is a
+** DELETE, pChanges is passed a NULL pointer.
+**
+** It returns a pointer to a Trigger structure containing a trigger
+** equivalent to the ON UPDATE or ON DELETE action specified by pFKey.
+** If the action is "NO ACTION" then a NULL pointer is returned (these actions
+** require no special handling by the triggers sub-system, code for them is
+** created by fkScanChildren()).
+**
+** For example, if pFKey is the foreign key and pTab is table "p" in
+** the following schema:
+**
+**   CREATE TABLE p(pk PRIMARY KEY);
+**   CREATE TABLE c(ck REFERENCES p ON DELETE CASCADE);
+**
+** then the returned trigger structure is equivalent to:
+**
+**   CREATE TRIGGER ... DELETE ON p BEGIN
+**     DELETE FROM c WHERE ck = old.pk;
+**   END;
+**
+** The returned pointer is cached as part of the foreign key object. It
+** is eventually freed along with the rest of the foreign key object by
+** sqlite3FkDelete().
+*/
+static Trigger *fkActionTrigger(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being updated or deleted from */
+  FKey *pFKey,                    /* Foreign key to get action for */
+  ExprList *pChanges              /* Change-list for UPDATE, NULL for DELETE */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  int action;                     /* One of OE_None, OE_Cascade etc. */
+  Trigger *pTrigger;              /* Trigger definition to return */
+  int iAction = (pChanges!=0);    /* 1 for UPDATE, 0 for DELETE */
+
+  action = pFKey->aAction[iAction];
+  if( (db->flags & SQLITE_FkNoAction) ) action = OE_None;
+  if( action==OE_Restrict && (db->flags & SQLITE_DeferFKs) ){
+    return 0;
+  }
+  pTrigger = pFKey->apTrigger[iAction];
+
+  if( action!=OE_None && !pTrigger ){
+    char const *zFrom;            /* Name of child table */
+    int nFrom;                    /* Length in bytes of zFrom */
+    Index *pIdx = 0;              /* Parent key index for this FK */
+    int *aiCol = 0;               /* child table cols -> parent key cols */
+    TriggerStep *pStep = 0;        /* First (only) step of trigger program */
+    Expr *pWhere = 0;             /* WHERE clause of trigger step */
+    ExprList *pList = 0;          /* Changes list if ON UPDATE CASCADE */
+    Select *pSelect = 0;          /* If RESTRICT, "SELECT RAISE(...)" */
+    int i;                        /* Iterator variable */
+    Expr *pWhen = 0;              /* WHEN clause for the trigger */
+
+    if( sqlite3FkLocateIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ) return 0;
+    assert( aiCol || pFKey->nCol==1 );
+
+    for(i=0; i<pFKey->nCol; i++){
+      Token tOld = { "old", 3 };  /* Literal "old" token */
+      Token tNew = { "new", 3 };  /* Literal "new" token */
+      Token tFromCol;             /* Name of column in child table */
+      Token tToCol;               /* Name of column in parent table */
+      int iFromCol;               /* Idx of column in child table */
+      Expr *pEq;                  /* tFromCol = OLD.tToCol */
+
+      iFromCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
+      assert( iFromCol>=0 );
+      assert( pIdx!=0 || (pTab->iPKey>=0 && pTab->iPKey<pTab->nCol) );
+      assert( pIdx==0 || pIdx->aiColumn[i]>=0 );
+      sqlite3TokenInit(&tToCol,
+                   pTab->aCol[pIdx ? pIdx->aiColumn[i] : pTab->iPKey].zCnName);
+      sqlite3TokenInit(&tFromCol, pFKey->pFrom->aCol[iFromCol].zCnName);
+
+      /* Create the expression "OLD.zToCol = zFromCol". It is important
+      ** that the "OLD.zToCol" term is on the LHS of the = operator, so
+      ** that the affinity and collation sequence associated with the
+      ** parent table are used for the comparison. */
+      pEq = sqlite3PExpr(pParse, TK_EQ,
+          sqlite3PExpr(pParse, TK_DOT,
+            sqlite3ExprAlloc(db, TK_ID, &tOld, 0),
+            sqlite3ExprAlloc(db, TK_ID, &tToCol, 0)),
+          sqlite3ExprAlloc(db, TK_ID, &tFromCol, 0)
+      );
+      pWhere = sqlite3ExprAnd(pParse, pWhere, pEq);
+
+      /* For ON UPDATE, construct the next term of the WHEN clause.
+      ** The final WHEN clause will be like this:
+      **
+      **    WHEN NOT(old.col1 IS new.col1 AND ... AND old.colN IS new.colN)
+      */
+      if( pChanges ){
+        pEq = sqlite3PExpr(pParse, TK_IS,
+            sqlite3PExpr(pParse, TK_DOT,
+              sqlite3ExprAlloc(db, TK_ID, &tOld, 0),
+              sqlite3ExprAlloc(db, TK_ID, &tToCol, 0)),
+            sqlite3PExpr(pParse, TK_DOT,
+              sqlite3ExprAlloc(db, TK_ID, &tNew, 0),
+              sqlite3ExprAlloc(db, TK_ID, &tToCol, 0))
+            );
+        pWhen = sqlite3ExprAnd(pParse, pWhen, pEq);
+      }
+
+      if( action!=OE_Restrict && (action!=OE_Cascade || pChanges) ){
+        Expr *pNew;
+        if( action==OE_Cascade ){
+          pNew = sqlite3PExpr(pParse, TK_DOT,
+            sqlite3ExprAlloc(db, TK_ID, &tNew, 0),
+            sqlite3ExprAlloc(db, TK_ID, &tToCol, 0));
+        }else if( action==OE_SetDflt ){
+          Column *pCol = pFKey->pFrom->aCol + iFromCol;
+          Expr *pDflt;
+          if( pCol->colFlags & COLFLAG_GENERATED ){
+            testcase( pCol->colFlags & COLFLAG_VIRTUAL );
+            testcase( pCol->colFlags & COLFLAG_STORED );
+            pDflt = 0;
+          }else{
+            pDflt = sqlite3ColumnExpr(pFKey->pFrom, pCol);
+          }
+          if( pDflt ){
+            pNew = sqlite3ExprDup(db, pDflt, 0);
+          }else{
+            pNew = sqlite3ExprAlloc(db, TK_NULL, 0, 0);
+          }
+        }else{
+          pNew = sqlite3ExprAlloc(db, TK_NULL, 0, 0);
+        }
+        pList = sqlite3ExprListAppend(pParse, pList, pNew);
+        sqlite3ExprListSetName(pParse, pList, &tFromCol, 0);
+      }
+    }
+    sqlite3DbFree(db, aiCol);
+
+    zFrom = pFKey->pFrom->zName;
+    nFrom = sqlite3Strlen30(zFrom);
+
+    if( action==OE_Restrict ){
+      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      SrcList *pSrc;
+      Expr *pRaise;
+
+      pRaise = sqlite3Expr(db, TK_STRING, "FOREIGN KEY constraint failed"),
+      pRaise = sqlite3PExpr(pParse, TK_RAISE, pRaise, 0);
+      if( pRaise ){
+        pRaise->affExpr = OE_Abort;
+      }
+      pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
+      if( pSrc ){
+        assert( pSrc->nSrc==1 );
+        pSrc->a[0].zName = sqlite3DbStrDup(db, zFrom);
+        assert( pSrc->a[0].fg.fixedSchema==0 && pSrc->a[0].fg.isSubquery==0 );
+        pSrc->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
+      }
+      pSelect = sqlite3SelectNew(pParse,
+          sqlite3ExprListAppend(pParse, 0, pRaise),
+          pSrc,
+          pWhere,
+          0, 0, 0, 0, 0
+      );
+      pWhere = 0;
+    }
+
+    /* Disable lookaside memory allocation */
+    DisableLookaside;
+
+    pTrigger = (Trigger *)sqlite3DbMallocZero(db,
+        sizeof(Trigger) +         /* struct Trigger */
+        sizeof(TriggerStep) +     /* Single step in trigger program */
+        nFrom + 1                 /* Space for pStep->zTarget */
+    );
+    if( pTrigger ){
+      pStep = pTrigger->step_list = (TriggerStep *)&pTrigger[1];
+      pStep->zTarget = (char *)&pStep[1];
+      memcpy((char *)pStep->zTarget, zFrom, nFrom);
+
+      pStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
+      pStep->pExprList = sqlite3ExprListDup(db, pList, EXPRDUP_REDUCE);
+      pStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
+      if( pWhen ){
+        pWhen = sqlite3PExpr(pParse, TK_NOT, pWhen, 0);
+        pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
+      }
+    }
+
+    /* Re-enable the lookaside buffer, if it was disabled earlier. */
+    EnableLookaside;
+
+    sqlite3ExprDelete(db, pWhere);
+    sqlite3ExprDelete(db, pWhen);
+    sqlite3ExprListDelete(db, pList);
+    sqlite3SelectDelete(db, pSelect);
+    if( db->mallocFailed==1 ){
+      fkTriggerDelete(db, pTrigger);
+      return 0;
+    }
+    assert( pStep!=0 );
+    assert( pTrigger!=0 );
+
+    switch( action ){
+      case OE_Restrict:
+        pStep->op = TK_SELECT;
+        break;
+      case OE_Cascade:
+        if( !pChanges ){
+          pStep->op = TK_DELETE;
+          break;
+        }
+        /* no break */ deliberate_fall_through
+      default:
+        pStep->op = TK_UPDATE;
+    }
+    pStep->pTrig = pTrigger;
+    pTrigger->pSchema = pTab->pSchema;
+    pTrigger->pTabSchema = pTab->pSchema;
+    pFKey->apTrigger[iAction] = pTrigger;
+    pTrigger->op = (pChanges ? TK_UPDATE : TK_DELETE);
+  }
+
+  return pTrigger;
+}
+
+/*
+** This function is called when deleting or updating a row to implement
+** any required CASCADE, SET NULL or SET DEFAULT actions.
+*/
+SQLITE_PRIVATE void sqlite3FkActions(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being updated or deleted from */
+  ExprList *pChanges,             /* Change-list for UPDATE, NULL for DELETE */
+  int regOld,                     /* Address of array containing old row */
+  int *aChange,                   /* Array indicating UPDATEd columns (or 0) */
+  int bChngRowid                  /* True if rowid is UPDATEd */
+){
+  /* If foreign-key support is enabled, iterate through all FKs that
+  ** refer to table pTab. If there is an action associated with the FK
+  ** for this operation (either update or delete), invoke the associated
+  ** trigger sub-program.  */
+  if( pParse->db->flags&SQLITE_ForeignKeys ){
+    FKey *pFKey;                  /* Iterator variable */
+    for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
+      if( aChange==0 || fkParentIsModified(pTab, pFKey, aChange, bChngRowid) ){
+        Trigger *pAct = fkActionTrigger(pParse, pTab, pFKey, pChanges);
+        if( pAct ){
+          sqlite3CodeRowTriggerDirect(pParse, pAct, pTab, regOld, OE_Abort, 0);
+        }
+      }
+    }
+  }
+}
+
+#endif /* ifndef SQLITE_OMIT_TRIGGER */
+
+/*
+** Free all memory associated with foreign key definitions attached to
+** table pTab. Remove the deleted foreign keys from the Schema.fkeyHash
+** hash table.
+*/
+SQLITE_PRIVATE void sqlite3FkDelete(sqlite3 *db, Table *pTab){
+  FKey *pFKey;                    /* Iterator variable */
+  FKey *pNext;                    /* Copy of pFKey->pNextFrom */
+
+  assert( IsOrdinaryTable(pTab) );
+  assert( db!=0 );
+  for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pNext){
+    assert( db==0 || sqlite3SchemaMutexHeld(db, 0, pTab->pSchema) );
+
+    /* Remove the FK from the fkeyHash hash table. */
+    if( db->pnBytesFreed==0 ){
+      if( pFKey->pPrevTo ){
+        pFKey->pPrevTo->pNextTo = pFKey->pNextTo;
+      }else{
+        const char *z = (pFKey->pNextTo ? pFKey->pNextTo->zTo : pFKey->zTo);
+        sqlite3HashInsert(&pTab->pSchema->fkeyHash, z, pFKey->pNextTo);
+      }
+      if( pFKey->pNextTo ){
+        pFKey->pNextTo->pPrevTo = pFKey->pPrevTo;
+      }
+    }
+
+    /* EV: R-30323-21917 Each foreign key constraint in SQLite is
+    ** classified as either immediate or deferred.
+    */
+    assert( pFKey->isDeferred==0 || pFKey->isDeferred==1 );
+
+    /* Delete any triggers created to implement actions for this FK. */
+#ifndef SQLITE_OMIT_TRIGGER
+    fkTriggerDelete(db, pFKey->apTrigger[0]);
+    fkTriggerDelete(db, pFKey->apTrigger[1]);
+#endif
+
+    pNext = pFKey->pNextFrom;
+    sqlite3DbFree(db, pFKey);
+  }
+}
+#endif /* ifndef SQLITE_OMIT_FOREIGN_KEY */
+
+/************** End of fkey.c ************************************************/
+/************** Begin file insert.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle INSERT statements in SQLite.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** Generate code that will
+**
+**   (1) acquire a lock for table pTab then
+**   (2) open pTab as cursor iCur.
+**
+** If pTab is a WITHOUT ROWID table, then it is the PRIMARY KEY index
+** for that table that is actually opened.
+*/
+SQLITE_PRIVATE void sqlite3OpenTable(
+  Parse *pParse,  /* Generate code into this VDBE */
+  int iCur,       /* The cursor number of the table */
+  int iDb,        /* The database index in sqlite3.aDb[] */
+  Table *pTab,    /* The table to be opened */
+  int opcode      /* OP_OpenRead or OP_OpenWrite */
+){
+  Vdbe *v;
+  assert( !IsVirtual(pTab) );
+  assert( pParse->pVdbe!=0 );
+  v = pParse->pVdbe;
+  assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
+  if( !pParse->db->noSharedCache ){
+    sqlite3TableLock(pParse, iDb, pTab->tnum,
+                     (opcode==OP_OpenWrite)?1:0, pTab->zName);
+  }
+  if( HasRowid(pTab) ){
+    sqlite3VdbeAddOp4Int(v, opcode, iCur, pTab->tnum, iDb, pTab->nNVCol);
+    VdbeComment((v, "%s", pTab->zName));
+  }else{
+    Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+    assert( pPk!=0 );
+    assert( pPk->tnum==pTab->tnum || CORRUPT_DB );
+    sqlite3VdbeAddOp3(v, opcode, iCur, pPk->tnum, iDb);
+    sqlite3VdbeSetP4KeyInfo(pParse, pPk);
+    VdbeComment((v, "%s", pTab->zName));
+  }
+}
+
+/*
+** Return a pointer to the column affinity string associated with index
+** pIdx. A column affinity string has one character for each column in
+** the table, according to the affinity of the column:
+**
+**  Character      Column affinity
+**  ------------------------------
+**  'A'            BLOB
+**  'B'            TEXT
+**  'C'            NUMERIC
+**  'D'            INTEGER
+**  'F'            REAL
+**
+** An extra 'D' is appended to the end of the string to cover the
+** rowid that appears as the last column in every index.
+**
+** Memory for the buffer containing the column index affinity string
+** is managed along with the rest of the Index structure. It will be
+** released when sqlite3DeleteIndex() is called.
+*/
+static SQLITE_NOINLINE const char *computeIndexAffStr(sqlite3 *db, Index *pIdx){
+  /* The first time a column affinity string for a particular index is
+  ** required, it is allocated and populated here. It is then stored as
+  ** a member of the Index structure for subsequent use.
+  **
+  ** The column affinity string will eventually be deleted by
+  ** sqliteDeleteIndex() when the Index structure itself is cleaned
+  ** up.
+  */
+  int n;
+  Table *pTab = pIdx->pTable;
+  pIdx->zColAff = (char *)sqlite3DbMallocRaw(0, pIdx->nColumn+1);
+  if( !pIdx->zColAff ){
+    sqlite3OomFault(db);
+    return 0;
+  }
+  for(n=0; n<pIdx->nColumn; n++){
+    i16 x = pIdx->aiColumn[n];
+    char aff;
+    if( x>=0 ){
+      aff = pTab->aCol[x].affinity;
+    }else if( x==XN_ROWID ){
+      aff = SQLITE_AFF_INTEGER;
+    }else{
+      assert( x==XN_EXPR );
+      assert( pIdx->bHasExpr );
+      assert( pIdx->aColExpr!=0 );
+      aff = sqlite3ExprAffinity(pIdx->aColExpr->a[n].pExpr);
+    }
+    if( aff<SQLITE_AFF_BLOB ) aff = SQLITE_AFF_BLOB;
+    if( aff>SQLITE_AFF_NUMERIC) aff = SQLITE_AFF_NUMERIC;
+    pIdx->zColAff[n] = aff;
+  }
+  pIdx->zColAff[n] = 0;
+  return pIdx->zColAff;
+}
+SQLITE_PRIVATE const char *sqlite3IndexAffinityStr(sqlite3 *db, Index *pIdx){
+  if( !pIdx->zColAff ) return computeIndexAffStr(db, pIdx);
+  return pIdx->zColAff;
+}
+
+
+/*
+** Compute an affinity string for a table.   Space is obtained
+** from sqlite3DbMalloc().  The caller is responsible for freeing
+** the space when done.
+*/
+SQLITE_PRIVATE char *sqlite3TableAffinityStr(sqlite3 *db, const Table *pTab){
+  char *zColAff;
+  zColAff = (char *)sqlite3DbMallocRaw(db, pTab->nCol+1);
+  if( zColAff ){
+    int i, j;
+    for(i=j=0; i<pTab->nCol; i++){
+      if( (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0 ){
+        zColAff[j++] = pTab->aCol[i].affinity;
+      }
+    }
+    do{
+      zColAff[j--] = 0;
+    }while( j>=0 && zColAff[j]<=SQLITE_AFF_BLOB );
+  }
+  return zColAff;
+}
+
+/*
+** Make changes to the evolving bytecode to do affinity transformations
+** of values that are about to be gathered into a row for table pTab.
+**
+** For ordinary (legacy, non-strict) tables:
+** -----------------------------------------
+**
+** Compute the affinity string for table pTab, if it has not already been
+** computed.  As an optimization, omit trailing SQLITE_AFF_BLOB affinities.
+**
+** If the affinity string is empty (because it was all SQLITE_AFF_BLOB entries
+** which were then optimized out) then this routine becomes a no-op.
+**
+** Otherwise if iReg>0 then code an OP_Affinity opcode that will set the
+** affinities for register iReg and following.  Or if iReg==0,
+** then just set the P4 operand of the previous opcode (which should  be
+** an OP_MakeRecord) to the affinity string.
+**
+** A column affinity string has one character per column:
+**
+**    Character      Column affinity
+**    ---------      ---------------
+**    'A'            BLOB
+**    'B'            TEXT
+**    'C'            NUMERIC
+**    'D'            INTEGER
+**    'E'            REAL
+**
+** For STRICT tables:
+** ------------------
+**
+** Generate an appropriate OP_TypeCheck opcode that will verify the
+** datatypes against the column definitions in pTab.  If iReg==0, that
+** means an OP_MakeRecord opcode has already been generated and should be
+** the last opcode generated.  The new OP_TypeCheck needs to be inserted
+** before the OP_MakeRecord.  The new OP_TypeCheck should use the same
+** register set as the OP_MakeRecord.  If iReg>0 then register iReg is
+** the first of a series of registers that will form the new record.
+** Apply the type checking to that array of registers.
+*/
+SQLITE_PRIVATE void sqlite3TableAffinity(Vdbe *v, Table *pTab, int iReg){
+  int i;
+  char *zColAff;
+  if( pTab->tabFlags & TF_Strict ){
+    if( iReg==0 ){
+      /* Move the previous opcode (which should be OP_MakeRecord) forward
+      ** by one slot and insert a new OP_TypeCheck where the current
+      ** OP_MakeRecord is found */
+      VdbeOp *pPrev;
+      sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+      pPrev = sqlite3VdbeGetLastOp(v);
+      assert( pPrev!=0 );
+      assert( pPrev->opcode==OP_MakeRecord || sqlite3VdbeDb(v)->mallocFailed );
+      pPrev->opcode = OP_TypeCheck;
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, pPrev->p1, pPrev->p2, pPrev->p3);
+    }else{
+      /* Insert an isolated OP_Typecheck */
+      sqlite3VdbeAddOp2(v, OP_TypeCheck, iReg, pTab->nNVCol);
+      sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+    }
+    return;
+  }
+  zColAff = pTab->zColAff;
+  if( zColAff==0 ){
+    zColAff = sqlite3TableAffinityStr(0, pTab);
+    if( !zColAff ){
+      sqlite3OomFault(sqlite3VdbeDb(v));
+      return;
+    }
+    pTab->zColAff = zColAff;
+  }
+  assert( zColAff!=0 );
+  i = sqlite3Strlen30NN(zColAff);
+  if( i ){
+    if( iReg ){
+      sqlite3VdbeAddOp4(v, OP_Affinity, iReg, i, 0, zColAff, i);
+    }else{
+      assert( sqlite3VdbeGetLastOp(v)->opcode==OP_MakeRecord
+              || sqlite3VdbeDb(v)->mallocFailed );
+      sqlite3VdbeChangeP4(v, -1, zColAff, i);
+    }
+  }
+}
+
+/*
+** Return non-zero if the table pTab in database iDb or any of its indices
+** have been opened at any point in the VDBE program. This is used to see if
+** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can
+** run without using a temporary table for the results of the SELECT.
+*/
+static int readsTable(Parse *p, int iDb, Table *pTab){
+  Vdbe *v = sqlite3GetVdbe(p);
+  int i;
+  int iEnd = sqlite3VdbeCurrentAddr(v);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;
+#endif
+
+  for(i=1; i<iEnd; i++){
+    VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
+    assert( pOp!=0 );
+    if( pOp->opcode==OP_OpenRead && pOp->p3==iDb ){
+      Index *pIndex;
+      Pgno tnum = pOp->p2;
+      if( tnum==pTab->tnum ){
+        return 1;
+      }
+      for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
+        if( tnum==pIndex->tnum ){
+          return 1;
+        }
+      }
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pVTab ){
+      assert( pOp->p4.pVtab!=0 );
+      assert( pOp->p4type==P4_VTAB );
+      return 1;
+    }
+#endif
+  }
+  return 0;
+}
+
+/* This walker callback will compute the union of colFlags flags for all
+** referenced columns in a CHECK constraint or generated column expression.
+*/
+static int exprColumnFlagUnion(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_COLUMN && pExpr->iColumn>=0 ){
+    assert( pExpr->iColumn < pWalker->u.pTab->nCol );
+    pWalker->eCode |= pWalker->u.pTab->aCol[pExpr->iColumn].colFlags;
+  }
+  return WRC_Continue;
+}
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+/*
+** All regular columns for table pTab have been puts into registers
+** starting with iRegStore.  The registers that correspond to STORED
+** or VIRTUAL columns have not yet been initialized.  This routine goes
+** back and computes the values for those columns based on the previously
+** computed normal columns.
+*/
+SQLITE_PRIVATE void sqlite3ComputeGeneratedColumns(
+  Parse *pParse,    /* Parsing context */
+  int iRegStore,    /* Register holding the first column */
+  Table *pTab       /* The table */
+){
+  int i;
+  Walker w;
+  Column *pRedo;
+  int eProgress;
+  VdbeOp *pOp;
+
+  assert( pTab->tabFlags & TF_HasGenerated );
+  testcase( pTab->tabFlags & TF_HasVirtual );
+  testcase( pTab->tabFlags & TF_HasStored );
+
+  /* Before computing generated columns, first go through and make sure
+  ** that appropriate affinity has been applied to the regular columns
+  */
+  sqlite3TableAffinity(pParse->pVdbe, pTab, iRegStore);
+  if( (pTab->tabFlags & TF_HasStored)!=0 ){
+    pOp = sqlite3VdbeGetLastOp(pParse->pVdbe);
+    if( pOp->opcode==OP_Affinity ){
+      /* Change the OP_Affinity argument to '@' (NONE) for all stored
+      ** columns.  '@' is the no-op affinity and those columns have not
+      ** yet been computed. */
+      int ii, jj;
+      char *zP4 = pOp->p4.z;
+      assert( zP4!=0 );
+      assert( pOp->p4type==P4_DYNAMIC );
+      for(ii=jj=0; zP4[jj]; ii++){
+        if( pTab->aCol[ii].colFlags & COLFLAG_VIRTUAL ){
+          continue;
+        }
+        if( pTab->aCol[ii].colFlags & COLFLAG_STORED ){
+          zP4[jj] = SQLITE_AFF_NONE;
+        }
+        jj++;
+      }
+    }else if( pOp->opcode==OP_TypeCheck ){
+      /* If an OP_TypeCheck was generated because the table is STRICT,
+      ** then set the P3 operand to indicate that generated columns should
+      ** not be checked */
+      pOp->p3 = 1;
+    }
+  }
+
+  /* Because there can be multiple generated columns that refer to one another,
+  ** this is a two-pass algorithm.  On the first pass, mark all generated
+  ** columns as "not available".
+  */
+  for(i=0; i<pTab->nCol; i++){
+    if( pTab->aCol[i].colFlags & COLFLAG_GENERATED ){
+      testcase( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL );
+      testcase( pTab->aCol[i].colFlags & COLFLAG_STORED );
+      pTab->aCol[i].colFlags |= COLFLAG_NOTAVAIL;
+    }
+  }
+
+  w.u.pTab = pTab;
+  w.xExprCallback = exprColumnFlagUnion;
+  w.xSelectCallback = 0;
+  w.xSelectCallback2 = 0;
+
+  /* On the second pass, compute the value of each NOT-AVAILABLE column.
+  ** Companion code in the TK_COLUMN case of sqlite3ExprCodeTarget() will
+  ** compute dependencies and mark remove the COLSPAN_NOTAVAIL mark, as
+  ** they are needed.
+  */
+  pParse->iSelfTab = -iRegStore;
+  do{
+    eProgress = 0;
+    pRedo = 0;
+    for(i=0; i<pTab->nCol; i++){
+      Column *pCol = pTab->aCol + i;
+      if( (pCol->colFlags & COLFLAG_NOTAVAIL)!=0 ){
+        int x;
+        pCol->colFlags |= COLFLAG_BUSY;
+        w.eCode = 0;
+        sqlite3WalkExpr(&w, sqlite3ColumnExpr(pTab, pCol));
+        pCol->colFlags &= ~COLFLAG_BUSY;
+        if( w.eCode & COLFLAG_NOTAVAIL ){
+          pRedo = pCol;
+          continue;
+        }
+        eProgress = 1;
+        assert( pCol->colFlags & COLFLAG_GENERATED );
+        x = sqlite3TableColumnToStorage(pTab, i) + iRegStore;
+        sqlite3ExprCodeGeneratedColumn(pParse, pTab, pCol, x);
+        pCol->colFlags &= ~COLFLAG_NOTAVAIL;
+      }
+    }
+  }while( pRedo && eProgress );
+  if( pRedo ){
+    sqlite3ErrorMsg(pParse, "generated column loop on \"%s\"", pRedo->zCnName);
+  }
+  pParse->iSelfTab = 0;
+}
+#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
+
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+/*
+** Locate or create an AutoincInfo structure associated with table pTab
+** which is in database iDb.  Return the register number for the register
+** that holds the maximum rowid.  Return zero if pTab is not an AUTOINCREMENT
+** table.  (Also return zero when doing a VACUUM since we do not want to
+** update the AUTOINCREMENT counters during a VACUUM.)
+**
+** There is at most one AutoincInfo structure per table even if the
+** same table is autoincremented multiple times due to inserts within
+** triggers.  A new AutoincInfo structure is created if this is the
+** first use of table pTab.  On 2nd and subsequent uses, the original
+** AutoincInfo structure is used.
+**
+** Four consecutive registers are allocated:
+**
+**   (1)  The name of the pTab table.
+**   (2)  The maximum ROWID of pTab.
+**   (3)  The rowid in sqlite_sequence of pTab
+**   (4)  The original value of the max ROWID in pTab, or NULL if none
+**
+** The 2nd register is the one that is returned.  That is all the
+** insert routine needs to know about.
+*/
+static int autoIncBegin(
+  Parse *pParse,      /* Parsing context */
+  int iDb,            /* Index of the database holding pTab */
+  Table *pTab         /* The table we are writing to */
+){
+  int memId = 0;      /* Register holding maximum rowid */
+  assert( pParse->db->aDb[iDb].pSchema!=0 );
+  if( (pTab->tabFlags & TF_Autoincrement)!=0
+   && (pParse->db->mDbFlags & DBFLAG_Vacuum)==0
+  ){
+    Parse *pToplevel = sqlite3ParseToplevel(pParse);
+    AutoincInfo *pInfo;
+    Table *pSeqTab = pParse->db->aDb[iDb].pSchema->pSeqTab;
+
+    /* Verify that the sqlite_sequence table exists and is an ordinary
+    ** rowid table with exactly two columns.
+    ** Ticket d8dc2b3a58cd5dc2918a1d4acb 2018-05-23 */
+    if( pSeqTab==0
+     || !HasRowid(pSeqTab)
+     || NEVER(IsVirtual(pSeqTab))
+     || pSeqTab->nCol!=2
+    ){
+      pParse->nErr++;
+      pParse->rc = SQLITE_CORRUPT_SEQUENCE;
+      return 0;
+    }
+
+    pInfo = pToplevel->pAinc;
+    while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
+    if( pInfo==0 ){
+      pInfo = sqlite3DbMallocRawNN(pParse->db, sizeof(*pInfo));
+      sqlite3ParserAddCleanup(pToplevel, sqlite3DbFree, pInfo);
+      testcase( pParse->earlyCleanup );
+      if( pParse->db->mallocFailed ) return 0;
+      pInfo->pNext = pToplevel->pAinc;
+      pToplevel->pAinc = pInfo;
+      pInfo->pTab = pTab;
+      pInfo->iDb = iDb;
+      pToplevel->nMem++;                  /* Register to hold name of table */
+      pInfo->regCtr = ++pToplevel->nMem;  /* Max rowid register */
+      pToplevel->nMem +=2;       /* Rowid in sqlite_sequence + orig max val */
+    }
+    memId = pInfo->regCtr;
+  }
+  return memId;
+}
+
+/*
+** This routine generates code that will initialize all of the
+** register used by the autoincrement tracker.
+*/
+SQLITE_PRIVATE void sqlite3AutoincrementBegin(Parse *pParse){
+  AutoincInfo *p;            /* Information about an AUTOINCREMENT */
+  sqlite3 *db = pParse->db;  /* The database connection */
+  Db *pDb;                   /* Database only autoinc table */
+  int memId;                 /* Register holding max rowid */
+  Vdbe *v = pParse->pVdbe;   /* VDBE under construction */
+
+  /* This routine is never called during trigger-generation.  It is
+  ** only called from the top-level */
+  assert( pParse->pTriggerTab==0 );
+  assert( sqlite3IsToplevel(pParse) );
+
+  assert( v );   /* We failed long ago if this is not so */
+  for(p = pParse->pAinc; p; p = p->pNext){
+    static const int iLn = VDBE_OFFSET_LINENO(2);
+    static const VdbeOpList autoInc[] = {
+      /* 0  */ {OP_Null,    0,  0, 0},
+      /* 1  */ {OP_Rewind,  0, 10, 0},
+      /* 2  */ {OP_Column,  0,  0, 0},
+      /* 3  */ {OP_Ne,      0,  9, 0},
+      /* 4  */ {OP_Rowid,   0,  0, 0},
+      /* 5  */ {OP_Column,  0,  1, 0},
+      /* 6  */ {OP_AddImm,  0,  0, 0},
+      /* 7  */ {OP_Copy,    0,  0, 0},
+      /* 8  */ {OP_Goto,    0, 11, 0},
+      /* 9  */ {OP_Next,    0,  2, 0},
+      /* 10 */ {OP_Integer, 0,  0, 0},
+      /* 11 */ {OP_Close,   0,  0, 0}
+    };
+    VdbeOp *aOp;
+    pDb = &db->aDb[p->iDb];
+    memId = p->regCtr;
+    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
+    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
+    sqlite3VdbeLoadString(v, memId-1, p->pTab->zName);
+    aOp = sqlite3VdbeAddOpList(v, ArraySize(autoInc), autoInc, iLn);
+    if( aOp==0 ) break;
+    aOp[0].p2 = memId;
+    aOp[0].p3 = memId+2;
+    aOp[2].p3 = memId;
+    aOp[3].p1 = memId-1;
+    aOp[3].p3 = memId;
+    aOp[3].p5 = SQLITE_JUMPIFNULL;
+    aOp[4].p2 = memId+1;
+    aOp[5].p3 = memId;
+    aOp[6].p1 = memId;
+    aOp[7].p2 = memId+2;
+    aOp[7].p1 = memId;
+    aOp[10].p2 = memId;
+    if( pParse->nTab==0 ) pParse->nTab = 1;
+  }
+}
+
+/*
+** Update the maximum rowid for an autoincrement calculation.
+**
+** This routine should be called when the regRowid register holds a
+** new rowid that is about to be inserted.  If that new rowid is
+** larger than the maximum rowid in the memId memory cell, then the
+** memory cell is updated.
+*/
+static void autoIncStep(Parse *pParse, int memId, int regRowid){
+  if( memId>0 ){
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
+  }
+}
+
+/*
+** This routine generates the code needed to write autoincrement
+** maximum rowid values back into the sqlite_sequence register.
+** Every statement that might do an INSERT into an autoincrement
+** table (either directly or through triggers) needs to call this
+** routine just before the "exit" code.
+*/
+static SQLITE_NOINLINE void autoIncrementEnd(Parse *pParse){
+  AutoincInfo *p;
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
+
+  assert( v );
+  for(p = pParse->pAinc; p; p = p->pNext){
+    static const int iLn = VDBE_OFFSET_LINENO(2);
+    static const VdbeOpList autoIncEnd[] = {
+      /* 0 */ {OP_NotNull,     0, 2, 0},
+      /* 1 */ {OP_NewRowid,    0, 0, 0},
+      /* 2 */ {OP_MakeRecord,  0, 2, 0},
+      /* 3 */ {OP_Insert,      0, 0, 0},
+      /* 4 */ {OP_Close,       0, 0, 0}
+    };
+    VdbeOp *aOp;
+    Db *pDb = &db->aDb[p->iDb];
+    int iRec;
+    int memId = p->regCtr;
+
+    iRec = sqlite3GetTempReg(pParse);
+    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
+    sqlite3VdbeAddOp3(v, OP_Le, memId+2, sqlite3VdbeCurrentAddr(v)+7, memId);
+    VdbeCoverage(v);
+    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
+    aOp = sqlite3VdbeAddOpList(v, ArraySize(autoIncEnd), autoIncEnd, iLn);
+    if( aOp==0 ) break;
+    aOp[0].p1 = memId+1;
+    aOp[1].p2 = memId+1;
+    aOp[2].p1 = memId-1;
+    aOp[2].p3 = iRec;
+    aOp[3].p2 = iRec;
+    aOp[3].p3 = memId+1;
+    aOp[3].p5 = OPFLAG_APPEND;
+    sqlite3ReleaseTempReg(pParse, iRec);
+  }
+}
+SQLITE_PRIVATE void sqlite3AutoincrementEnd(Parse *pParse){
+  if( pParse->pAinc ) autoIncrementEnd(pParse);
+}
+#else
+/*
+** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
+** above are all no-ops
+*/
+# define autoIncBegin(A,B,C) (0)
+# define autoIncStep(A,B,C)
+#endif /* SQLITE_OMIT_AUTOINCREMENT */
+
+/*
+** If argument pVal is a Select object returned by an sqlite3MultiValues()
+** that was able to use the co-routine optimization, finish coding the
+** co-routine.
+*/
+SQLITE_PRIVATE void sqlite3MultiValuesEnd(Parse *pParse, Select *pVal){
+  if( ALWAYS(pVal) && pVal->pSrc->nSrc>0 ){
+    SrcItem *pItem = &pVal->pSrc->a[0];
+    assert( (pItem->fg.isSubquery && pItem->u4.pSubq!=0) || pParse->nErr );
+    if( pItem->fg.isSubquery ){
+      sqlite3VdbeEndCoroutine(pParse->pVdbe, pItem->u4.pSubq->regReturn);
+      sqlite3VdbeJumpHere(pParse->pVdbe, pItem->u4.pSubq->addrFillSub - 1);
+    }
+  }
+}
+
+/*
+** Return true if all expressions in the expression-list passed as the
+** only argument are constant.
+*/
+static int exprListIsConstant(Parse *pParse, ExprList *pRow){
+  int ii;
+  for(ii=0; ii<pRow->nExpr; ii++){
+    if( 0==sqlite3ExprIsConstant(pParse, pRow->a[ii].pExpr) ) return 0;
+  }
+  return 1;
+}
+
+/*
+** Return true if all expressions in the expression-list passed as the
+** only argument are both constant and have no affinity.
+*/
+static int exprListIsNoAffinity(Parse *pParse, ExprList *pRow){
+  int ii;
+  if( exprListIsConstant(pParse,pRow)==0 ) return 0;
+  for(ii=0; ii<pRow->nExpr; ii++){
+    Expr *pExpr = pRow->a[ii].pExpr;
+    assert( pExpr->op!=TK_RAISE );
+    assert( pExpr->affExpr==0 );
+    if( 0!=sqlite3ExprAffinity(pExpr) ) return 0;
+  }
+  return 1;
+
+}
+
+/*
+** This function is called by the parser for the second and subsequent
+** rows of a multi-row VALUES clause. Argument pLeft is the part of
+** the VALUES clause already parsed, argument pRow is the vector of values
+** for the new row. The Select object returned represents the complete
+** VALUES clause, including the new row.
+**
+** There are two ways in which this may be achieved - by incremental
+** coding of a co-routine (the "co-routine" method) or by returning a
+** Select object equivalent to the following (the "UNION ALL" method):
+**
+**        "pLeft UNION ALL SELECT pRow"
+**
+** If the VALUES clause contains a lot of rows, this compound Select
+** object may consume a lot of memory.
+**
+** When the co-routine method is used, each row that will be returned
+** by the VALUES clause is coded into part of a co-routine as it is
+** passed to this function. The returned Select object is equivalent to:
+**
+**     SELECT * FROM (
+**       Select object to read co-routine
+**     )
+**
+** The co-routine method is used in most cases. Exceptions are:
+**
+**    a) If the current statement has a WITH clause. This is to avoid
+**       statements like:
+**
+**            WITH cte AS ( VALUES('x'), ('y') ... )
+**            SELECT * FROM cte AS a, cte AS b;
+**
+**       This will not work, as the co-routine uses a hard-coded register
+**       for its OP_Yield instructions, and so it is not possible for two
+**       cursors to iterate through it concurrently.
+**
+**    b) The schema is currently being parsed (i.e. the VALUES clause is part
+**       of a schema item like a VIEW or TRIGGER). In this case there is no VM
+**       being generated when parsing is taking place, and so generating
+**       a co-routine is not possible.
+**
+**    c) There are non-constant expressions in the VALUES clause (e.g.
+**       the VALUES clause is part of a correlated sub-query).
+**
+**    d) One or more of the values in the first row of the VALUES clause
+**       has an affinity (i.e. is a CAST expression). This causes problems
+**       because the complex rules SQLite uses (see function
+**       sqlite3SubqueryColumnTypes() in select.c) to determine the effective
+**       affinity of such a column for all rows require access to all values in
+**       the column simultaneously.
+*/
+SQLITE_PRIVATE Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){
+
+  if( pParse->bHasWith                   /* condition (a) above */
+   || pParse->db->init.busy              /* condition (b) above */
+   || exprListIsConstant(pParse,pRow)==0 /* condition (c) above */
+   || (pLeft->pSrc->nSrc==0 &&
+       exprListIsNoAffinity(pParse,pLeft->pEList)==0) /* condition (d) above */
+   || IN_SPECIAL_PARSE
+  ){
+    /* The co-routine method cannot be used. Fall back to UNION ALL. */
+    Select *pSelect = 0;
+    int f = SF_Values | SF_MultiValue;
+    if( pLeft->pSrc->nSrc ){
+      sqlite3MultiValuesEnd(pParse, pLeft);
+      f = SF_Values;
+    }else if( pLeft->pPrior ){
+      /* In this case set the SF_MultiValue flag only if it was set on pLeft */
+      f = (f & pLeft->selFlags);
+    }
+    pSelect = sqlite3SelectNew(pParse, pRow, 0, 0, 0, 0, 0, f, 0);
+    pLeft->selFlags &= ~SF_MultiValue;
+    if( pSelect ){
+      pSelect->op = TK_ALL;
+      pSelect->pPrior = pLeft;
+      pLeft = pSelect;
+    }
+  }else{
+    SrcItem *p = 0;               /* SrcItem that reads from co-routine */
+
+    if( pLeft->pSrc->nSrc==0 ){
+      /* Co-routine has not yet been started and the special Select object
+      ** that accesses the co-routine has not yet been created. This block
+      ** does both those things. */
+      Vdbe *v = sqlite3GetVdbe(pParse);
+      Select *pRet = sqlite3SelectNew(pParse, 0, 0, 0, 0, 0, 0, 0, 0);
+
+      /* Ensure the database schema has been read. This is to ensure we have
+      ** the correct text encoding.  */
+      if( (pParse->db->mDbFlags & DBFLAG_SchemaKnownOk)==0 ){
+        sqlite3ReadSchema(pParse);
+      }
+
+      if( pRet ){
+        SelectDest dest;
+        Subquery *pSubq;
+        pRet->pSrc->nSrc = 1;
+        pRet->pPrior = pLeft->pPrior;
+        pRet->op = pLeft->op;
+        if( pRet->pPrior ) pRet->selFlags |= SF_Values;
+        pLeft->pPrior = 0;
+        pLeft->op = TK_SELECT;
+        assert( pLeft->pNext==0 );
+        assert( pRet->pNext==0 );
+        p = &pRet->pSrc->a[0];
+        p->fg.viaCoroutine = 1;
+        p->iCursor = -1;
+        assert( !p->fg.isIndexedBy && !p->fg.isTabFunc );
+        p->u1.nRow = 2;
+        if( sqlite3SrcItemAttachSubquery(pParse, p, pLeft, 0) ){
+          pSubq = p->u4.pSubq;
+          pSubq->addrFillSub = sqlite3VdbeCurrentAddr(v) + 1;
+          pSubq->regReturn = ++pParse->nMem;
+          sqlite3VdbeAddOp3(v, OP_InitCoroutine,
+                            pSubq->regReturn, 0, pSubq->addrFillSub);
+          sqlite3SelectDestInit(&dest, SRT_Coroutine, pSubq->regReturn);
+
+          /* Allocate registers for the output of the co-routine. Do so so
+          ** that there are two unused registers immediately before those
+          ** used by the co-routine. This allows the code in sqlite3Insert()
+          ** to use these registers directly, instead of copying the output
+          ** of the co-routine to a separate array for processing.  */
+          dest.iSdst = pParse->nMem + 3;
+          dest.nSdst = pLeft->pEList->nExpr;
+          pParse->nMem += 2 + dest.nSdst;
+
+          pLeft->selFlags |= SF_MultiValue;
+          sqlite3Select(pParse, pLeft, &dest);
+          pSubq->regResult = dest.iSdst;
+          assert( pParse->nErr || dest.iSdst>0 );
+        }
+        pLeft = pRet;
+      }
+    }else{
+      p = &pLeft->pSrc->a[0];
+      assert( !p->fg.isTabFunc && !p->fg.isIndexedBy );
+      p->u1.nRow++;
+    }
+
+    if( pParse->nErr==0 ){
+      Subquery *pSubq;
+      assert( p!=0 );
+      assert( p->fg.isSubquery );
+      pSubq = p->u4.pSubq;
+      assert( pSubq!=0 );
+      assert( pSubq->pSelect!=0 );
+      assert( pSubq->pSelect->pEList!=0 );
+      if( pSubq->pSelect->pEList->nExpr!=pRow->nExpr ){
+        sqlite3SelectWrongNumTermsError(pParse, pSubq->pSelect);
+      }else{
+        sqlite3ExprCodeExprList(pParse, pRow, pSubq->regResult, 0, 0);
+        sqlite3VdbeAddOp1(pParse->pVdbe, OP_Yield, pSubq->regReturn);
+      }
+    }
+    sqlite3ExprListDelete(pParse->db, pRow);
+  }
+
+  return pLeft;
+}
+
+/* Forward declaration */
+static int xferOptimization(
+  Parse *pParse,        /* Parser context */
+  Table *pDest,         /* The table we are inserting into */
+  Select *pSelect,      /* A SELECT statement to use as the data source */
+  int onError,          /* How to handle constraint errors */
+  int iDbDest           /* The database of pDest */
+);
+
+/*
+** This routine is called to handle SQL of the following forms:
+**
+**    insert into TABLE (IDLIST) values(EXPRLIST),(EXPRLIST),...
+**    insert into TABLE (IDLIST) select
+**    insert into TABLE (IDLIST) default values
+**
+** The IDLIST following the table name is always optional.  If omitted,
+** then a list of all (non-hidden) columns for the table is substituted.
+** The IDLIST appears in the pColumn parameter.  pColumn is NULL if IDLIST
+** is omitted.
+**
+** For the pSelect parameter holds the values to be inserted for the
+** first two forms shown above.  A VALUES clause is really just short-hand
+** for a SELECT statement that omits the FROM clause and everything else
+** that follows.  If the pSelect parameter is NULL, that means that the
+** DEFAULT VALUES form of the INSERT statement is intended.
+**
+** The code generated follows one of four templates.  For a simple
+** insert with data coming from a single-row VALUES clause, the code executes
+** once straight down through.  Pseudo-code follows (we call this
+** the "1st template"):
+**
+**         open write cursor to <table> and its indices
+**         put VALUES clause expressions into registers
+**         write the resulting record into <table>
+**         cleanup
+**
+** The three remaining templates assume the statement is of the form
+**
+**   INSERT INTO <table> SELECT ...
+**
+** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
+** in other words if the SELECT pulls all columns from a single table
+** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
+** if <table2> and <table1> are distinct tables but have identical
+** schemas, including all the same indices, then a special optimization
+** is invoked that copies raw records from <table2> over to <table1>.
+** See the xferOptimization() function for the implementation of this
+** template.  This is the 2nd template.
+**
+**         open a write cursor to <table>
+**         open read cursor on <table2>
+**         transfer all records in <table2> over to <table>
+**         close cursors
+**         foreach index on <table>
+**           open a write cursor on the <table> index
+**           open a read cursor on the corresponding <table2> index
+**           transfer all records from the read to the write cursors
+**           close cursors
+**         end foreach
+**
+** The 3rd template is for when the second template does not apply
+** and the SELECT clause does not read from <table> at any time.
+** The generated code follows this template:
+**
+**         X <- A
+**         goto B
+**      A: setup for the SELECT
+**         loop over the rows in the SELECT
+**           load values into registers R..R+n
+**           yield X
+**         end loop
+**         cleanup after the SELECT
+**         end-coroutine X
+**      B: open write cursor to <table> and its indices
+**      C: yield X, at EOF goto D
+**         insert the select result into <table> from R..R+n
+**         goto C
+**      D: cleanup
+**
+** The 4th template is used if the insert statement takes its
+** values from a SELECT but the data is being inserted into a table
+** that is also read as part of the SELECT.  In the third form,
+** we have to use an intermediate table to store the results of
+** the select.  The template is like this:
+**
+**         X <- A
+**         goto B
+**      A: setup for the SELECT
+**         loop over the tables in the SELECT
+**           load value into register R..R+n
+**           yield X
+**         end loop
+**         cleanup after the SELECT
+**         end co-routine R
+**      B: open temp table
+**      L: yield X, at EOF goto M
+**         insert row from R..R+n into temp table
+**         goto L
+**      M: open write cursor to <table> and its indices
+**         rewind temp table
+**      C: loop over rows of intermediate table
+**           transfer values form intermediate table into <table>
+**         end loop
+**      D: cleanup
+*/
+SQLITE_PRIVATE void sqlite3Insert(
+  Parse *pParse,        /* Parser context */
+  SrcList *pTabList,    /* Name of table into which we are inserting */
+  Select *pSelect,      /* A SELECT statement to use as the data source */
+  IdList *pColumn,      /* Column names corresponding to IDLIST, or NULL. */
+  int onError,          /* How to handle constraint errors */
+  Upsert *pUpsert       /* ON CONFLICT clauses for upsert, or NULL */
+){
+  sqlite3 *db;          /* The main database structure */
+  Table *pTab;          /* The table to insert into.  aka TABLE */
+  int i, j;             /* Loop counters */
+  Vdbe *v;              /* Generate code into this virtual machine */
+  Index *pIdx;          /* For looping over indices of the table */
+  int nColumn;          /* Number of columns in the data */
+  int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
+  int iDataCur = 0;     /* VDBE cursor that is the main data repository */
+  int iIdxCur = 0;      /* First index cursor */
+  int ipkColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
+  int endOfLoop;        /* Label for the end of the insertion loop */
+  int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
+  int addrInsTop = 0;   /* Jump to label "D" */
+  int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
+  SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
+  int iDb;              /* Index of database holding TABLE */
+  u8 useTempTable = 0;  /* Store SELECT results in intermediate table */
+  u8 appendFlag = 0;    /* True if the insert is likely to be an append */
+  u8 withoutRowid;      /* 0 for normal table.  1 for WITHOUT ROWID table */
+  u8 bIdListInOrder;    /* True if IDLIST is in table order */
+  ExprList *pList = 0;  /* List of VALUES() to be inserted  */
+  int iRegStore;        /* Register in which to store next column */
+
+  /* Register allocations */
+  int regFromSelect = 0;/* Base register for data coming from SELECT */
+  int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
+  int regRowCount = 0;  /* Memory cell used for the row counter */
+  int regIns;           /* Block of regs holding rowid+data being inserted */
+  int regRowid;         /* registers holding insert rowid */
+  int regData;          /* register holding first column to insert */
+  int *aRegIdx = 0;     /* One register allocated to each index */
+  int *aTabColMap = 0;  /* Mapping from pTab columns to pCol entries */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;                 /* True if attempting to insert into a view */
+  Trigger *pTrigger;          /* List of triggers on pTab, if required */
+  int tmask;                  /* Mask of trigger times */
+#endif
+
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nErr ){
+    goto insert_cleanup;
+  }
+  assert( db->mallocFailed==0 );
+  dest.iSDParm = 0;  /* Suppress a harmless compiler warning */
+
+  /* If the Select object is really just a simple VALUES() list with a
+  ** single row (the common case) then keep that one row of values
+  ** and discard the other (unused) parts of the pSelect object
+  */
+  if( pSelect && (pSelect->selFlags & SF_Values)!=0 && pSelect->pPrior==0 ){
+    pList = pSelect->pEList;
+    pSelect->pEList = 0;
+    sqlite3SelectDelete(db, pSelect);
+    pSelect = 0;
+  }
+
+  /* Locate the table into which we will be inserting new information.
+  */
+  assert( pTabList->nSrc==1 );
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 ){
+    goto insert_cleanup;
+  }
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb<db->nDb );
+  if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0,
+                       db->aDb[iDb].zDbSName) ){
+    goto insert_cleanup;
+  }
+  withoutRowid = !HasRowid(pTab);
+
+  /* Figure out if we have any triggers and if the table being
+  ** inserted into is a view
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
+  isView = IsView(pTab);
+#else
+# define pTrigger 0
+# define tmask 0
+# define isView 0
+#endif
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+  assert( (pTrigger && tmask) || (pTrigger==0 && tmask==0) );
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x10000 ){
+    sqlite3TreeViewLine(0, "In sqlite3Insert() at %s:%d", __FILE__, __LINE__);
+    sqlite3TreeViewInsert(pParse->pWith, pTabList, pColumn, pSelect, pList,
+                          onError, pUpsert, pTrigger);
+  }
+#endif
+
+  /* If pTab is really a view, make sure it has been initialized.
+  ** ViewGetColumnNames() is a no-op if pTab is not a view.
+  */
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto insert_cleanup;
+  }
+
+  /* Cannot insert into a read-only table.
+  */
+  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
+    goto insert_cleanup;
+  }
+
+  /* Allocate a VDBE
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) goto insert_cleanup;
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);
+
+#ifndef SQLITE_OMIT_XFER_OPT
+  /* If the statement is of the form
+  **
+  **       INSERT INTO <table1> SELECT * FROM <table2>;
+  **
+  ** Then special optimizations can be applied that make the transfer
+  ** very fast and which reduce fragmentation of indices.
+  **
+  ** This is the 2nd template.
+  */
+  if( pColumn==0
+   && pSelect!=0
+   && pTrigger==0
+   && xferOptimization(pParse, pTab, pSelect, onError, iDb)
+  ){
+    assert( !pTrigger );
+    assert( pList==0 );
+    goto insert_end;
+  }
+#endif /* SQLITE_OMIT_XFER_OPT */
+
+  /* If this is an AUTOINCREMENT table, look up the sequence number in the
+  ** sqlite_sequence table and store it in memory cell regAutoinc.
+  */
+  regAutoinc = autoIncBegin(pParse, iDb, pTab);
+
+  /* Allocate a block registers to hold the rowid and the values
+  ** for all columns of the new row.
+  */
+  regRowid = regIns = pParse->nMem+1;
+  pParse->nMem += pTab->nCol + 1;
+  if( IsVirtual(pTab) ){
+    regRowid++;
+    pParse->nMem++;
+  }
+  regData = regRowid+1;
+
+  /* If the INSERT statement included an IDLIST term, then make sure
+  ** all elements of the IDLIST really are columns of the table and
+  ** remember the column indices.
+  **
+  ** If the table has an INTEGER PRIMARY KEY column and that column
+  ** is named in the IDLIST, then record in the ipkColumn variable
+  ** the index into IDLIST of the primary key column.  ipkColumn is
+  ** the index of the primary key as it appears in IDLIST, not as
+  ** is appears in the original table.  (The index of the INTEGER
+  ** PRIMARY KEY in the original table is pTab->iPKey.)  After this
+  ** loop, if ipkColumn==(-1), that means that integer primary key
+  ** is unspecified, and hence the table is either WITHOUT ROWID or
+  ** it will automatically generated an integer primary key.
+  **
+  ** bIdListInOrder is true if the columns in IDLIST are in storage
+  ** order.  This enables an optimization that avoids shuffling the
+  ** columns into storage order.  False negatives are harmless,
+  ** but false positives will cause database corruption.
+  */
+  bIdListInOrder = (pTab->tabFlags & (TF_OOOHidden|TF_HasStored))==0;
+  if( pColumn ){
+    aTabColMap = sqlite3DbMallocZero(db, pTab->nCol*sizeof(int));
+    if( aTabColMap==0 ) goto insert_cleanup;
+    for(i=0; i<pColumn->nId; i++){
+      const char *zCName = pColumn->a[i].zName;
+      u8 hName = sqlite3StrIHash(zCName);
+      for(j=0; j<pTab->nCol; j++){
+        if( pTab->aCol[j].hName!=hName ) continue;
+        if( sqlite3StrICmp(zCName, pTab->aCol[j].zCnName)==0 ){
+          if( aTabColMap[j]==0 ) aTabColMap[j] = i+1;
+          if( i!=j ) bIdListInOrder = 0;
+          if( j==pTab->iPKey ){
+            ipkColumn = i;  assert( !withoutRowid );
+          }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+          if( pTab->aCol[j].colFlags & (COLFLAG_STORED|COLFLAG_VIRTUAL) ){
+            sqlite3ErrorMsg(pParse,
+               "cannot INSERT into generated column \"%s\"",
+               pTab->aCol[j].zCnName);
+            goto insert_cleanup;
+          }
+#endif
+          break;
+        }
+      }
+      if( j>=pTab->nCol ){
+        if( sqlite3IsRowid(pColumn->a[i].zName) && !withoutRowid ){
+          ipkColumn = i;
+          bIdListInOrder = 0;
+        }else{
+          sqlite3ErrorMsg(pParse, "table %S has no column named %s",
+              pTabList->a, pColumn->a[i].zName);
+          pParse->checkSchema = 1;
+          goto insert_cleanup;
+        }
+      }
+    }
+  }
+
+  /* Figure out how many columns of data are supplied.  If the data
+  ** is coming from a SELECT statement, then generate a co-routine that
+  ** produces a single row of the SELECT on each invocation.  The
+  ** co-routine is the common header to the 3rd and 4th templates.
+  */
+  if( pSelect ){
+    /* Data is coming from a SELECT or from a multi-row VALUES clause.
+    ** Generate a co-routine to run the SELECT. */
+    int rc;             /* Result code */
+
+    if( pSelect->pSrc->nSrc==1
+     && pSelect->pSrc->a[0].fg.viaCoroutine
+     && pSelect->pPrior==0
+    ){
+      SrcItem *pItem = &pSelect->pSrc->a[0];
+      Subquery *pSubq;
+      assert( pItem->fg.isSubquery );
+      pSubq = pItem->u4.pSubq;
+      dest.iSDParm = pSubq->regReturn;
+      regFromSelect = pSubq->regResult;
+      assert( pSubq->pSelect!=0 );
+      assert( pSubq->pSelect->pEList!=0 );
+      nColumn = pSubq->pSelect->pEList->nExpr;
+      ExplainQueryPlan((pParse, 0, "SCAN %S", pItem));
+      if( bIdListInOrder && nColumn==pTab->nCol ){
+        regData = regFromSelect;
+        regRowid = regData - 1;
+        regIns = regRowid - (IsVirtual(pTab) ? 1 : 0);
+      }
+    }else{
+      int addrTop;        /* Top of the co-routine */
+      int regYield = ++pParse->nMem;
+      addrTop = sqlite3VdbeCurrentAddr(v) + 1;
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
+      dest.iSdst = bIdListInOrder ? regData : 0;
+      dest.nSdst = pTab->nCol;
+      rc = sqlite3Select(pParse, pSelect, &dest);
+      regFromSelect = dest.iSdst;
+      assert( db->pParse==pParse );
+      if( rc || pParse->nErr ) goto insert_cleanup;
+      assert( db->mallocFailed==0 );
+      sqlite3VdbeEndCoroutine(v, regYield);
+      sqlite3VdbeJumpHere(v, addrTop - 1);                       /* label B: */
+      assert( pSelect->pEList );
+      nColumn = pSelect->pEList->nExpr;
+    }
+
+    /* Set useTempTable to TRUE if the result of the SELECT statement
+    ** should be written into a temporary table (template 4).  Set to
+    ** FALSE if each output row of the SELECT can be written directly into
+    ** the destination table (template 3).
+    **
+    ** A temp table must be used if the table being updated is also one
+    ** of the tables being read by the SELECT statement.  Also use a
+    ** temp table in the case of row triggers.
+    */
+    if( pTrigger || readsTable(pParse, iDb, pTab) ){
+      useTempTable = 1;
+    }
+
+    if( useTempTable ){
+      /* Invoke the coroutine to extract information from the SELECT
+      ** and add it to a transient table srcTab.  The code generated
+      ** here is from the 4th template:
+      **
+      **      B: open temp table
+      **      L: yield X, goto M at EOF
+      **         insert row from R..R+n into temp table
+      **         goto L
+      **      M: ...
+      */
+      int regRec;          /* Register to hold packed record */
+      int regTempRowid;    /* Register to hold temp table ROWID */
+      int addrL;           /* Label "L" */
+
+      srcTab = pParse->nTab++;
+      regRec = sqlite3GetTempReg(pParse);
+      regTempRowid = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
+      addrL = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm); VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
+      sqlite3VdbeGoto(v, addrL);
+      sqlite3VdbeJumpHere(v, addrL);
+      sqlite3ReleaseTempReg(pParse, regRec);
+      sqlite3ReleaseTempReg(pParse, regTempRowid);
+    }
+  }else{
+    /* This is the case if the data for the INSERT is coming from a
+    ** single-row VALUES clause
+    */
+    NameContext sNC;
+    memset(&sNC, 0, sizeof(sNC));
+    sNC.pParse = pParse;
+    srcTab = -1;
+    assert( useTempTable==0 );
+    if( pList ){
+      nColumn = pList->nExpr;
+      if( sqlite3ResolveExprListNames(&sNC, pList) ){
+        goto insert_cleanup;
+      }
+    }else{
+      nColumn = 0;
+    }
+  }
+
+  /* If there is no IDLIST term but the table has an integer primary
+  ** key, the set the ipkColumn variable to the integer primary key
+  ** column index in the original table definition.
+  */
+  if( pColumn==0 && nColumn>0 ){
+    ipkColumn = pTab->iPKey;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    if( ipkColumn>=0 && (pTab->tabFlags & TF_HasGenerated)!=0 ){
+      testcase( pTab->tabFlags & TF_HasVirtual );
+      testcase( pTab->tabFlags & TF_HasStored );
+      for(i=ipkColumn-1; i>=0; i--){
+        if( pTab->aCol[i].colFlags & COLFLAG_GENERATED ){
+          testcase( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL );
+          testcase( pTab->aCol[i].colFlags & COLFLAG_STORED );
+          ipkColumn--;
+        }
+      }
+    }
+#endif
+
+    /* Make sure the number of columns in the source data matches the number
+    ** of columns to be inserted into the table.
+    */
+    assert( TF_HasHidden==COLFLAG_HIDDEN );
+    assert( TF_HasGenerated==COLFLAG_GENERATED );
+    assert( COLFLAG_NOINSERT==(COLFLAG_GENERATED|COLFLAG_HIDDEN) );
+    if( (pTab->tabFlags & (TF_HasGenerated|TF_HasHidden))!=0 ){
+      for(i=0; i<pTab->nCol; i++){
+        if( pTab->aCol[i].colFlags & COLFLAG_NOINSERT ) nHidden++;
+      }
+    }
+    if( nColumn!=(pTab->nCol-nHidden) ){
+      sqlite3ErrorMsg(pParse,
+         "table %S has %d columns but %d values were supplied",
+         pTabList->a, pTab->nCol-nHidden, nColumn);
+     goto insert_cleanup;
+    }
+  }
+  if( pColumn!=0 && nColumn!=pColumn->nId ){
+    sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
+    goto insert_cleanup;
+  }
+
+  /* Initialize the count of rows to be inserted
+  */
+  if( (db->flags & SQLITE_CountRows)!=0
+   && !pParse->nested
+   && !pParse->pTriggerTab
+   && !pParse->bReturning
+  ){
+    regRowCount = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
+  }
+
+  /* If this is not a view, open the table and and all indices */
+  if( !isView ){
+    int nIdx;
+    nIdx = sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, -1, 0,
+                                      &iDataCur, &iIdxCur);
+    aRegIdx = sqlite3DbMallocRawNN(db, sizeof(int)*(nIdx+2));
+    if( aRegIdx==0 ){
+      goto insert_cleanup;
+    }
+    for(i=0, pIdx=pTab->pIndex; i<nIdx; pIdx=pIdx->pNext, i++){
+      assert( pIdx );
+      aRegIdx[i] = ++pParse->nMem;
+      pParse->nMem += pIdx->nColumn;
+    }
+    aRegIdx[i] = ++pParse->nMem;  /* Register to store the table record */
+  }
+#ifndef SQLITE_OMIT_UPSERT
+  if( pUpsert ){
+    Upsert *pNx;
+    if( IsVirtual(pTab) ){
+      sqlite3ErrorMsg(pParse, "UPSERT not implemented for virtual table \"%s\"",
+              pTab->zName);
+      goto insert_cleanup;
+    }
+    if( IsView(pTab) ){
+      sqlite3ErrorMsg(pParse, "cannot UPSERT a view");
+      goto insert_cleanup;
+    }
+    if( sqlite3HasExplicitNulls(pParse, pUpsert->pUpsertTarget) ){
+      goto insert_cleanup;
+    }
+    pTabList->a[0].iCursor = iDataCur;
+    pNx = pUpsert;
+    do{
+      pNx->pUpsertSrc = pTabList;
+      pNx->regData = regData;
+      pNx->iDataCur = iDataCur;
+      pNx->iIdxCur = iIdxCur;
+      if( pNx->pUpsertTarget ){
+        if( sqlite3UpsertAnalyzeTarget(pParse, pTabList, pNx, pUpsert) ){
+          goto insert_cleanup;
+        }
+      }
+      pNx = pNx->pNextUpsert;
+    }while( pNx!=0 );
+  }
+#endif
+
+
+  /* This is the top of the main insertion loop */
+  if( useTempTable ){
+    /* This block codes the top of loop only.  The complete loop is the
+    ** following pseudocode (template 4):
+    **
+    **         rewind temp table, if empty goto D
+    **      C: loop over rows of intermediate table
+    **           transfer values form intermediate table into <table>
+    **         end loop
+    **      D: ...
+    */
+    addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab); VdbeCoverage(v);
+    addrCont = sqlite3VdbeCurrentAddr(v);
+  }else if( pSelect ){
+    /* This block codes the top of loop only.  The complete loop is the
+    ** following pseudocode (template 3):
+    **
+    **      C: yield X, at EOF goto D
+    **         insert the select result into <table> from R..R+n
+    **         goto C
+    **      D: ...
+    */
+    sqlite3VdbeReleaseRegisters(pParse, regData, pTab->nCol, 0, 0);
+    addrInsTop = addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
+    VdbeCoverage(v);
+    if( ipkColumn>=0 ){
+      /* tag-20191021-001: If the INTEGER PRIMARY KEY is being generated by the
+      ** SELECT, go ahead and copy the value into the rowid slot now, so that
+      ** the value does not get overwritten by a NULL at tag-20191021-002. */
+      sqlite3VdbeAddOp2(v, OP_Copy, regFromSelect+ipkColumn, regRowid);
+    }
+  }
+
+  /* Compute data for ordinary columns of the new entry.  Values
+  ** are written in storage order into registers starting with regData.
+  ** Only ordinary columns are computed in this loop. The rowid
+  ** (if there is one) is computed later and generated columns are
+  ** computed after the rowid since they might depend on the value
+  ** of the rowid.
+  */
+  nHidden = 0;
+  iRegStore = regData;  assert( regData==regRowid+1 );
+  for(i=0; i<pTab->nCol; i++, iRegStore++){
+    int k;
+    u32 colFlags;
+    assert( i>=nHidden );
+    if( i==pTab->iPKey ){
+      /* tag-20191021-002: References to the INTEGER PRIMARY KEY are filled
+      ** using the rowid. So put a NULL in the IPK slot of the record to avoid
+      ** using excess space.  The file format definition requires this extra
+      ** NULL - we cannot optimize further by skipping the column completely */
+      sqlite3VdbeAddOp1(v, OP_SoftNull, iRegStore);
+      continue;
+    }
+    if( ((colFlags = pTab->aCol[i].colFlags) & COLFLAG_NOINSERT)!=0 ){
+      nHidden++;
+      if( (colFlags & COLFLAG_VIRTUAL)!=0 ){
+        /* Virtual columns do not participate in OP_MakeRecord.  So back up
+        ** iRegStore by one slot to compensate for the iRegStore++ in the
+        ** outer for() loop */
+        iRegStore--;
+        continue;
+      }else if( (colFlags & COLFLAG_STORED)!=0 ){
+        /* Stored columns are computed later.  But if there are BEFORE
+        ** triggers, the slots used for stored columns will be OP_Copy-ed
+        ** to a second block of registers, so the register needs to be
+        ** initialized to NULL to avoid an uninitialized register read */
+        if( tmask & TRIGGER_BEFORE ){
+          sqlite3VdbeAddOp1(v, OP_SoftNull, iRegStore);
+        }
+        continue;
+      }else if( pColumn==0 ){
+        /* Hidden columns that are not explicitly named in the INSERT
+        ** get there default value */
+        sqlite3ExprCodeFactorable(pParse,
+            sqlite3ColumnExpr(pTab, &pTab->aCol[i]),
+            iRegStore);
+        continue;
+      }
+    }
+    if( pColumn ){
+      j = aTabColMap[i];
+      assert( j>=0 && j<=pColumn->nId );
+      if( j==0 ){
+        /* A column not named in the insert column list gets its
+        ** default value */
+        sqlite3ExprCodeFactorable(pParse,
+            sqlite3ColumnExpr(pTab, &pTab->aCol[i]),
+            iRegStore);
+        continue;
+      }
+      k = j - 1;
+    }else if( nColumn==0 ){
+      /* This is INSERT INTO ... DEFAULT VALUES.  Load the default value. */
+      sqlite3ExprCodeFactorable(pParse,
+          sqlite3ColumnExpr(pTab, &pTab->aCol[i]),
+          iRegStore);
+      continue;
+    }else{
+      k = i - nHidden;
+    }
+
+    if( useTempTable ){
+      sqlite3VdbeAddOp3(v, OP_Column, srcTab, k, iRegStore);
+    }else if( pSelect ){
+      if( regFromSelect!=regData ){
+        sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+k, iRegStore);
+      }
+    }else{
+      Expr *pX = pList->a[k].pExpr;
+      int y = sqlite3ExprCodeTarget(pParse, pX, iRegStore);
+      if( y!=iRegStore ){
+        sqlite3VdbeAddOp2(v,
+          ExprHasProperty(pX, EP_Subquery) ? OP_Copy : OP_SCopy, y, iRegStore);
+      }
+    }
+  }
+
+
+  /* Run the BEFORE and INSTEAD OF triggers, if there are any
+  */
+  endOfLoop = sqlite3VdbeMakeLabel(pParse);
+  if( tmask & TRIGGER_BEFORE ){
+    int regCols = sqlite3GetTempRange(pParse, pTab->nCol+1);
+
+    /* build the NEW.* reference row.  Note that if there is an INTEGER
+    ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
+    ** translated into a unique ID for the row.  But on a BEFORE trigger,
+    ** we do not know what the unique ID will be (because the insert has
+    ** not happened yet) so we substitute a rowid of -1
+    */
+    if( ipkColumn<0 ){
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
+    }else{
+      int addr1;
+      assert( !withoutRowid );
+      if( useTempTable ){
+        sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regCols);
+      }else{
+        assert( pSelect==0 );  /* Otherwise useTempTable is true */
+        sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regCols);
+      }
+      addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regCols); VdbeCoverage(v);
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
+      sqlite3VdbeJumpHere(v, addr1);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, regCols); VdbeCoverage(v);
+    }
+
+    /* Copy the new data already generated. */
+    assert( pTab->nNVCol>0 || pParse->nErr>0 );
+    sqlite3VdbeAddOp3(v, OP_Copy, regRowid+1, regCols+1, pTab->nNVCol-1);
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    /* Compute the new value for generated columns after all other
+    ** columns have already been computed.  This must be done after
+    ** computing the ROWID in case one of the generated columns
+    ** refers to the ROWID. */
+    if( pTab->tabFlags & TF_HasGenerated ){
+      testcase( pTab->tabFlags & TF_HasVirtual );
+      testcase( pTab->tabFlags & TF_HasStored );
+      sqlite3ComputeGeneratedColumns(pParse, regCols+1, pTab);
+    }
+#endif
+
+    /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
+    ** do not attempt any conversions before assembling the record.
+    ** If this is a real table, attempt conversions as required by the
+    ** table column affinities.
+    */
+    if( !isView ){
+      sqlite3TableAffinity(v, pTab, regCols+1);
+    }
+
+    /* Fire BEFORE or INSTEAD OF triggers */
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE,
+        pTab, regCols-pTab->nCol-1, onError, endOfLoop);
+
+    sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol+1);
+  }
+
+  if( !isView ){
+    if( IsVirtual(pTab) ){
+      /* The row that the VUpdate opcode will delete: none */
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regIns);
+    }
+    if( ipkColumn>=0 ){
+      /* Compute the new rowid */
+      if( useTempTable ){
+        sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regRowid);
+      }else if( pSelect ){
+        /* Rowid already initialized at tag-20191021-001 */
+      }else{
+        Expr *pIpk = pList->a[ipkColumn].pExpr;
+        if( pIpk->op==TK_NULL && !IsVirtual(pTab) ){
+          sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
+          appendFlag = 1;
+        }else{
+          sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regRowid);
+        }
+      }
+      /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
+      ** to generate a unique primary key value.
+      */
+      if( !appendFlag ){
+        int addr1;
+        if( !IsVirtual(pTab) ){
+          addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid); VdbeCoverage(v);
+          sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
+          sqlite3VdbeJumpHere(v, addr1);
+        }else{
+          addr1 = sqlite3VdbeCurrentAddr(v);
+          sqlite3VdbeAddOp2(v, OP_IsNull, regRowid, addr1+2); VdbeCoverage(v);
+        }
+        sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid); VdbeCoverage(v);
+      }
+    }else if( IsVirtual(pTab) || withoutRowid ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
+      appendFlag = 1;
+    }
+    autoIncStep(pParse, regAutoinc, regRowid);
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    /* Compute the new value for generated columns after all other
+    ** columns have already been computed.  This must be done after
+    ** computing the ROWID in case one of the generated columns
+    ** is derived from the INTEGER PRIMARY KEY. */
+    if( pTab->tabFlags & TF_HasGenerated ){
+      sqlite3ComputeGeneratedColumns(pParse, regRowid+1, pTab);
+    }
+#endif
+
+    /* Generate code to check constraints and generate index keys and
+    ** do the insertion.
+    */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( IsVirtual(pTab) ){
+      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
+      sqlite3VtabMakeWritable(pParse, pTab);
+      sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
+      sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
+      sqlite3MayAbort(pParse);
+    }else
+#endif
+    {
+      int isReplace = 0;/* Set to true if constraints may cause a replace */
+      int bUseSeek;     /* True to use OPFLAG_SEEKRESULT */
+      sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
+          regIns, 0, ipkColumn>=0, onError, endOfLoop, &isReplace, 0, pUpsert
+      );
+      if( db->flags & SQLITE_ForeignKeys ){
+        sqlite3FkCheck(pParse, pTab, 0, regIns, 0, 0);
+      }
+
+      /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
+      ** constraints or (b) there are no triggers and this table is not a
+      ** parent table in a foreign key constraint. It is safe to set the
+      ** flag in the second case as if any REPLACE constraint is hit, an
+      ** OP_Delete or OP_IdxDelete instruction will be executed on each
+      ** cursor that is disturbed. And these instructions both clear the
+      ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
+      ** functionality.  */
+      bUseSeek = (isReplace==0 || !sqlite3VdbeHasSubProgram(v));
+      sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
+          regIns, aRegIdx, 0, appendFlag, bUseSeek
+      );
+    }
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  }else if( pParse->bReturning ){
+    /* If there is a RETURNING clause, populate the rowid register with
+    ** constant value -1, in case one or more of the returned expressions
+    ** refer to the "rowid" of the view.  */
+    sqlite3VdbeAddOp2(v, OP_Integer, -1, regRowid);
+#endif
+  }
+
+  /* Update the count of rows that are inserted
+  */
+  if( regRowCount ){
+    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
+  }
+
+  if( pTrigger ){
+    /* Code AFTER triggers */
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER,
+        pTab, regData-2-pTab->nCol, onError, endOfLoop);
+  }
+
+  /* The bottom of the main insertion loop, if the data source
+  ** is a SELECT statement.
+  */
+  sqlite3VdbeResolveLabel(v, endOfLoop);
+  if( useTempTable ){
+    sqlite3VdbeAddOp2(v, OP_Next, srcTab, addrCont); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addrInsTop);
+    sqlite3VdbeAddOp1(v, OP_Close, srcTab);
+  }else if( pSelect ){
+    sqlite3VdbeGoto(v, addrCont);
+#ifdef SQLITE_DEBUG
+    /* If we are jumping back to an OP_Yield that is preceded by an
+    ** OP_ReleaseReg, set the p5 flag on the OP_Goto so that the
+    ** OP_ReleaseReg will be included in the loop. */
+    if( sqlite3VdbeGetOp(v, addrCont-1)->opcode==OP_ReleaseReg ){
+      assert( sqlite3VdbeGetOp(v, addrCont)->opcode==OP_Yield );
+      sqlite3VdbeChangeP5(v, 1);
+    }
+#endif
+    sqlite3VdbeJumpHere(v, addrInsTop);
+  }
+
+#ifndef SQLITE_OMIT_XFER_OPT
+insert_end:
+#endif /* SQLITE_OMIT_XFER_OPT */
+  /* Update the sqlite_sequence table by storing the content of the
+  ** maximum rowid counter values recorded while inserting into
+  ** autoincrement tables.
+  */
+  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
+    sqlite3AutoincrementEnd(pParse);
+  }
+
+  /*
+  ** Return the number of rows inserted. If this routine is
+  ** generating code because of a call to sqlite3NestedParse(), do not
+  ** invoke the callback function.
+  */
+  if( regRowCount ){
+    sqlite3CodeChangeCount(v, regRowCount, "rows inserted");
+  }
+
+insert_cleanup:
+  sqlite3SrcListDelete(db, pTabList);
+  sqlite3ExprListDelete(db, pList);
+  sqlite3UpsertDelete(db, pUpsert);
+  sqlite3SelectDelete(db, pSelect);
+  if( pColumn ){
+    sqlite3IdListDelete(db, pColumn);
+    sqlite3DbFree(db, aTabColMap);
+  }
+  if( aRegIdx ) sqlite3DbNNFreeNN(db, aRegIdx);
+}
+
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** they may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
+#ifdef tmask
+ #undef tmask
+#endif
+
+/*
+** Meanings of bits in of pWalker->eCode for
+** sqlite3ExprReferencesUpdatedColumn()
+*/
+#define CKCNSTRNT_COLUMN   0x01    /* CHECK constraint uses a changing column */
+#define CKCNSTRNT_ROWID    0x02    /* CHECK constraint references the ROWID */
+
+/* This is the Walker callback from sqlite3ExprReferencesUpdatedColumn().
+*  Set bit 0x01 of pWalker->eCode if pWalker->eCode to 0 and if this
+** expression node references any of the
+** columns that are being modified by an UPDATE statement.
+*/
+static int checkConstraintExprNode(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_COLUMN ){
+    assert( pExpr->iColumn>=0 || pExpr->iColumn==-1 );
+    if( pExpr->iColumn>=0 ){
+      if( pWalker->u.aiCol[pExpr->iColumn]>=0 ){
+        pWalker->eCode |= CKCNSTRNT_COLUMN;
+      }
+    }else{
+      pWalker->eCode |= CKCNSTRNT_ROWID;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** pExpr is a CHECK constraint on a row that is being UPDATE-ed.  The
+** only columns that are modified by the UPDATE are those for which
+** aiChng[i]>=0, and also the ROWID is modified if chngRowid is true.
+**
+** Return true if CHECK constraint pExpr uses any of the
+** changing columns (or the rowid if it is changing).  In other words,
+** return true if this CHECK constraint must be validated for
+** the new row in the UPDATE statement.
+**
+** 2018-09-15: pExpr might also be an expression for an index-on-expressions.
+** The operation of this routine is the same - return true if an only if
+** the expression uses one or more of columns identified by the second and
+** third arguments.
+*/
+SQLITE_PRIVATE int sqlite3ExprReferencesUpdatedColumn(
+  Expr *pExpr,    /* The expression to be checked */
+  int *aiChng,    /* aiChng[x]>=0 if column x changed by the UPDATE */
+  int chngRowid   /* True if UPDATE changes the rowid */
+){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.eCode = 0;
+  w.xExprCallback = checkConstraintExprNode;
+  w.u.aiCol = aiChng;
+  sqlite3WalkExpr(&w, pExpr);
+  if( !chngRowid ){
+    testcase( (w.eCode & CKCNSTRNT_ROWID)!=0 );
+    w.eCode &= ~CKCNSTRNT_ROWID;
+  }
+  testcase( w.eCode==0 );
+  testcase( w.eCode==CKCNSTRNT_COLUMN );
+  testcase( w.eCode==CKCNSTRNT_ROWID );
+  testcase( w.eCode==(CKCNSTRNT_ROWID|CKCNSTRNT_COLUMN) );
+  return w.eCode!=0;
+}
+
+/*
+** The sqlite3GenerateConstraintChecks() routine usually wants to visit
+** the indexes of a table in the order provided in the Table->pIndex list.
+** However, sometimes (rarely - when there is an upsert) it wants to visit
+** the indexes in a different order.  The following data structures accomplish
+** this.
+**
+** The IndexIterator object is used to walk through all of the indexes
+** of a table in either Index.pNext order, or in some other order established
+** by an array of IndexListTerm objects.
+*/
+typedef struct IndexListTerm IndexListTerm;
+typedef struct IndexIterator IndexIterator;
+struct IndexIterator {
+  int eType;    /* 0 for Index.pNext list.  1 for an array of IndexListTerm */
+  int i;        /* Index of the current item from the list */
+  union {
+    struct {    /* Use this object for eType==0: A Index.pNext list */
+      Index *pIdx;   /* The current Index */
+    } lx;
+    struct {    /* Use this object for eType==1; Array of IndexListTerm */
+      int nIdx;               /* Size of the array */
+      IndexListTerm *aIdx;    /* Array of IndexListTerms */
+    } ax;
+  } u;
+};
+
+/* When IndexIterator.eType==1, then each index is an array of instances
+** of the following object
+*/
+struct IndexListTerm {
+  Index *p;  /* The index */
+  int ix;    /* Which entry in the original Table.pIndex list is this index*/
+};
+
+/* Return the first index on the list */
+static Index *indexIteratorFirst(IndexIterator *pIter, int *pIx){
+  assert( pIter->i==0 );
+  if( pIter->eType ){
+    *pIx = pIter->u.ax.aIdx[0].ix;
+    return pIter->u.ax.aIdx[0].p;
+  }else{
+    *pIx = 0;
+    return pIter->u.lx.pIdx;
+  }
+}
+
+/* Return the next index from the list.  Return NULL when out of indexes */
+static Index *indexIteratorNext(IndexIterator *pIter, int *pIx){
+  if( pIter->eType ){
+    int i = ++pIter->i;
+    if( i>=pIter->u.ax.nIdx ){
+      *pIx = i;
+      return 0;
+    }
+    *pIx = pIter->u.ax.aIdx[i].ix;
+    return pIter->u.ax.aIdx[i].p;
+  }else{
+    ++(*pIx);
+    pIter->u.lx.pIdx = pIter->u.lx.pIdx->pNext;
+    return pIter->u.lx.pIdx;
+  }
+}
+
+/*
+** Generate code to do constraint checks prior to an INSERT or an UPDATE
+** on table pTab.
+**
+** The regNewData parameter is the first register in a range that contains
+** the data to be inserted or the data after the update.  There will be
+** pTab->nCol+1 registers in this range.  The first register (the one
+** that regNewData points to) will contain the new rowid, or NULL in the
+** case of a WITHOUT ROWID table.  The second register in the range will
+** contain the content of the first table column.  The third register will
+** contain the content of the second table column.  And so forth.
+**
+** The regOldData parameter is similar to regNewData except that it contains
+** the data prior to an UPDATE rather than afterwards.  regOldData is zero
+** for an INSERT.  This routine can distinguish between UPDATE and INSERT by
+** checking regOldData for zero.
+**
+** For an UPDATE, the pkChng boolean is true if the true primary key (the
+** rowid for a normal table or the PRIMARY KEY for a WITHOUT ROWID table)
+** might be modified by the UPDATE.  If pkChng is false, then the key of
+** the iDataCur content table is guaranteed to be unchanged by the UPDATE.
+**
+** For an INSERT, the pkChng boolean indicates whether or not the rowid
+** was explicitly specified as part of the INSERT statement.  If pkChng
+** is zero, it means that the either rowid is computed automatically or
+** that the table is a WITHOUT ROWID table and has no rowid.  On an INSERT,
+** pkChng will only be true if the INSERT statement provides an integer
+** value for either the rowid column or its INTEGER PRIMARY KEY alias.
+**
+** The code generated by this routine will store new index entries into
+** registers identified by aRegIdx[].  No index entry is created for
+** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
+** the same as the order of indices on the linked list of indices
+** at pTab->pIndex.
+**
+** (2019-05-07) The generated code also creates a new record for the
+** main table, if pTab is a rowid table, and stores that record in the
+** register identified by aRegIdx[nIdx] - in other words in the first
+** entry of aRegIdx[] past the last index.  It is important that the
+** record be generated during constraint checks to avoid affinity changes
+** to the register content that occur after constraint checks but before
+** the new record is inserted.
+**
+** The caller must have already opened writeable cursors on the main
+** table and all applicable indices (that is to say, all indices for which
+** aRegIdx[] is not zero).  iDataCur is the cursor for the main table when
+** inserting or updating a rowid table, or the cursor for the PRIMARY KEY
+** index when operating on a WITHOUT ROWID table.  iIdxCur is the cursor
+** for the first index in the pTab->pIndex list.  Cursors for other indices
+** are at iIdxCur+N for the N-th element of the pTab->pIndex list.
+**
+** This routine also generates code to check constraints.  NOT NULL,
+** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
+** then the appropriate action is performed.  There are five possible
+** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
+**
+**  Constraint type  Action       What Happens
+**  ---------------  ----------   ----------------------------------------
+**  any              ROLLBACK     The current transaction is rolled back and
+**                                sqlite3_step() returns immediately with a
+**                                return code of SQLITE_CONSTRAINT.
+**
+**  any              ABORT        Back out changes from the current command
+**                                only (do not do a complete rollback) then
+**                                cause sqlite3_step() to return immediately
+**                                with SQLITE_CONSTRAINT.
+**
+**  any              FAIL         Sqlite3_step() returns immediately with a
+**                                return code of SQLITE_CONSTRAINT.  The
+**                                transaction is not rolled back and any
+**                                changes to prior rows are retained.
+**
+**  any              IGNORE       The attempt in insert or update the current
+**                                row is skipped, without throwing an error.
+**                                Processing continues with the next row.
+**                                (There is an immediate jump to ignoreDest.)
+**
+**  NOT NULL         REPLACE      The NULL value is replace by the default
+**                                value for that column.  If the default value
+**                                is NULL, the action is the same as ABORT.
+**
+**  UNIQUE           REPLACE      The other row that conflicts with the row
+**                                being inserted is removed.
+**
+**  CHECK            REPLACE      Illegal.  The results in an exception.
+**
+** Which action to take is determined by the overrideError parameter.
+** Or if overrideError==OE_Default, then the pParse->onError parameter
+** is used.  Or if pParse->onError==OE_Default then the onError value
+** for the constraint is used.
+*/
+SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
+  Parse *pParse,       /* The parser context */
+  Table *pTab,         /* The table being inserted or updated */
+  int *aRegIdx,        /* Use register aRegIdx[i] for index i.  0 for unused */
+  int iDataCur,        /* Canonical data cursor (main table or PK index) */
+  int iIdxCur,         /* First index cursor */
+  int regNewData,      /* First register in a range holding values to insert */
+  int regOldData,      /* Previous content.  0 for INSERTs */
+  u8 pkChng,           /* Non-zero if the rowid or PRIMARY KEY changed */
+  u8 overrideError,    /* Override onError to this if not OE_Default */
+  int ignoreDest,      /* Jump to this label on an OE_Ignore resolution */
+  int *pbMayReplace,   /* OUT: Set to true if constraint may cause a replace */
+  int *aiChng,         /* column i is unchanged if aiChng[i]<0 */
+  Upsert *pUpsert      /* ON CONFLICT clauses, if any.  NULL otherwise */
+){
+  Vdbe *v;             /* VDBE under construction */
+  Index *pIdx;         /* Pointer to one of the indices */
+  Index *pPk = 0;      /* The PRIMARY KEY index for WITHOUT ROWID tables */
+  sqlite3 *db;         /* Database connection */
+  int i;               /* loop counter */
+  int ix;              /* Index loop counter */
+  int nCol;            /* Number of columns */
+  int onError;         /* Conflict resolution strategy */
+  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
+  int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
+  Upsert *pUpsertClause = 0;  /* The specific ON CONFLICT clause for pIdx */
+  u8 isUpdate;           /* True if this is an UPDATE operation */
+  u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
+  int upsertIpkReturn = 0; /* Address of Goto at end of IPK uniqueness check */
+  int upsertIpkDelay = 0;  /* Address of Goto to bypass initial IPK check */
+  int ipkTop = 0;        /* Top of the IPK uniqueness check */
+  int ipkBottom = 0;     /* OP_Goto at the end of the IPK uniqueness check */
+  /* Variables associated with retesting uniqueness constraints after
+  ** replace triggers fire have run */
+  int regTrigCnt;       /* Register used to count replace trigger invocations */
+  int addrRecheck = 0;  /* Jump here to recheck all uniqueness constraints */
+  int lblRecheckOk = 0; /* Each recheck jumps to this label if it passes */
+  Trigger *pTrigger;    /* List of DELETE triggers on the table pTab */
+  int nReplaceTrig = 0; /* Number of replace triggers coded */
+  IndexIterator sIdxIter;  /* Index iterator */
+
+  isUpdate = regOldData!=0;
+  db = pParse->db;
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  assert( !IsView(pTab) );  /* This table is not a VIEW */
+  nCol = pTab->nCol;
+
+  /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
+  ** normal rowid tables.  nPkField is the number of key fields in the
+  ** pPk index or 1 for a rowid table.  In other words, nPkField is the
+  ** number of fields in the true primary key of the table. */
+  if( HasRowid(pTab) ){
+    pPk = 0;
+    nPkField = 1;
+  }else{
+    pPk = sqlite3PrimaryKeyIndex(pTab);
+    nPkField = pPk->nKeyCol;
+  }
+
+  /* Record that this module has started */
+  VdbeModuleComment((v, "BEGIN: GenCnstCks(%d,%d,%d,%d,%d)",
+                     iDataCur, iIdxCur, regNewData, regOldData, pkChng));
+
+  /* Test all NOT NULL constraints.
+  */
+  if( pTab->tabFlags & TF_HasNotNull ){
+    int b2ndPass = 0;         /* True if currently running 2nd pass */
+    int nSeenReplace = 0;     /* Number of ON CONFLICT REPLACE operations */
+    int nGenerated = 0;       /* Number of generated columns with NOT NULL */
+    while(1){  /* Make 2 passes over columns. Exit loop via "break" */
+      for(i=0; i<nCol; i++){
+        int iReg;                        /* Register holding column value */
+        Column *pCol = &pTab->aCol[i];   /* The column to check for NOT NULL */
+        int isGenerated;                 /* non-zero if column is generated */
+        onError = pCol->notNull;
+        if( onError==OE_None ) continue; /* No NOT NULL on this column */
+        if( i==pTab->iPKey ){
+          continue;        /* ROWID is never NULL */
+        }
+        isGenerated = pCol->colFlags & COLFLAG_GENERATED;
+        if( isGenerated && !b2ndPass ){
+          nGenerated++;
+          continue;        /* Generated columns processed on 2nd pass */
+        }
+        if( aiChng && aiChng[i]<0 && !isGenerated ){
+          /* Do not check NOT NULL on columns that do not change */
+          continue;
+        }
+        if( overrideError!=OE_Default ){
+          onError = overrideError;
+        }else if( onError==OE_Default ){
+          onError = OE_Abort;
+        }
+        if( onError==OE_Replace ){
+          if( b2ndPass        /* REPLACE becomes ABORT on the 2nd pass */
+           || pCol->iDflt==0  /* REPLACE is ABORT if no DEFAULT value */
+          ){
+            testcase( pCol->colFlags & COLFLAG_VIRTUAL );
+            testcase( pCol->colFlags & COLFLAG_STORED );
+            testcase( pCol->colFlags & COLFLAG_GENERATED );
+            onError = OE_Abort;
+          }else{
+            assert( !isGenerated );
+          }
+        }else if( b2ndPass && !isGenerated ){
+          continue;
+        }
+        assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
+            || onError==OE_Ignore || onError==OE_Replace );
+        testcase( i!=sqlite3TableColumnToStorage(pTab, i) );
+        iReg = sqlite3TableColumnToStorage(pTab, i) + regNewData + 1;
+        switch( onError ){
+          case OE_Replace: {
+            int addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, iReg);
+            VdbeCoverage(v);
+            assert( (pCol->colFlags & COLFLAG_GENERATED)==0 );
+            nSeenReplace++;
+            sqlite3ExprCodeCopy(pParse,
+               sqlite3ColumnExpr(pTab, pCol), iReg);
+            sqlite3VdbeJumpHere(v, addr1);
+            break;
+          }
+          case OE_Abort:
+            sqlite3MayAbort(pParse);
+            /* no break */ deliberate_fall_through
+          case OE_Rollback:
+          case OE_Fail: {
+            char *zMsg = sqlite3MPrintf(db, "%s.%s", pTab->zName,
+                                        pCol->zCnName);
+            testcase( zMsg==0 && db->mallocFailed==0 );
+            sqlite3VdbeAddOp3(v, OP_HaltIfNull, SQLITE_CONSTRAINT_NOTNULL,
+                              onError, iReg);
+            sqlite3VdbeAppendP4(v, zMsg, P4_DYNAMIC);
+            sqlite3VdbeChangeP5(v, P5_ConstraintNotNull);
+            VdbeCoverage(v);
+            break;
+          }
+          default: {
+            assert( onError==OE_Ignore );
+            sqlite3VdbeAddOp2(v, OP_IsNull, iReg, ignoreDest);
+            VdbeCoverage(v);
+            break;
+          }
+        } /* end switch(onError) */
+      } /* end loop i over columns */
+      if( nGenerated==0 && nSeenReplace==0 ){
+        /* If there are no generated columns with NOT NULL constraints
+        ** and no NOT NULL ON CONFLICT REPLACE constraints, then a single
+        ** pass is sufficient */
+        break;
+      }
+      if( b2ndPass ) break;  /* Never need more than 2 passes */
+      b2ndPass = 1;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+      if( nSeenReplace>0 && (pTab->tabFlags & TF_HasGenerated)!=0 ){
+        /* If any NOT NULL ON CONFLICT REPLACE constraints fired on the
+        ** first pass, recomputed values for all generated columns, as
+        ** those values might depend on columns affected by the REPLACE.
+        */
+        sqlite3ComputeGeneratedColumns(pParse, regNewData+1, pTab);
+      }
+#endif
+    } /* end of 2-pass loop */
+  } /* end if( has-not-null-constraints ) */
+
+  /* Test all CHECK constraints
+  */
+#ifndef SQLITE_OMIT_CHECK
+  if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
+    ExprList *pCheck = pTab->pCheck;
+    pParse->iSelfTab = -(regNewData+1);
+    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
+    for(i=0; i<pCheck->nExpr; i++){
+      int allOk;
+      Expr *pCopy;
+      Expr *pExpr = pCheck->a[i].pExpr;
+      if( aiChng
+       && !sqlite3ExprReferencesUpdatedColumn(pExpr, aiChng, pkChng)
+      ){
+        /* The check constraints do not reference any of the columns being
+        ** updated so there is no point it verifying the check constraint */
+        continue;
+      }
+      if( bAffinityDone==0 ){
+        sqlite3TableAffinity(v, pTab, regNewData+1);
+        bAffinityDone = 1;
+      }
+      allOk = sqlite3VdbeMakeLabel(pParse);
+      sqlite3VdbeVerifyAbortable(v, onError);
+      pCopy = sqlite3ExprDup(db, pExpr, 0);
+      if( !db->mallocFailed ){
+        sqlite3ExprIfTrue(pParse, pCopy, allOk, SQLITE_JUMPIFNULL);
+      }
+      sqlite3ExprDelete(db, pCopy);
+      if( onError==OE_Ignore ){
+        sqlite3VdbeGoto(v, ignoreDest);
+      }else{
+        char *zName = pCheck->a[i].zEName;
+        assert( zName!=0 || pParse->db->mallocFailed );
+        if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-26383-51744 */
+        sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_CHECK,
+                              onError, zName, P4_TRANSIENT,
+                              P5_ConstraintCheck);
+      }
+      sqlite3VdbeResolveLabel(v, allOk);
+    }
+    pParse->iSelfTab = 0;
+  }
+#endif /* !defined(SQLITE_OMIT_CHECK) */
+
+  /* UNIQUE and PRIMARY KEY constraints should be handled in the following
+  ** order:
+  **
+  **   (1)  OE_Update
+  **   (2)  OE_Abort, OE_Fail, OE_Rollback, OE_Ignore
+  **   (3)  OE_Replace
+  **
+  ** OE_Fail and OE_Ignore must happen before any changes are made.
+  ** OE_Update guarantees that only a single row will change, so it
+  ** must happen before OE_Replace.  Technically, OE_Abort and OE_Rollback
+  ** could happen in any order, but they are grouped up front for
+  ** convenience.
+  **
+  ** 2018-08-14: Ticket https://www.sqlite.org/src/info/908f001483982c43
+  ** The order of constraints used to have OE_Update as (2) and OE_Abort
+  ** and so forth as (1). But apparently PostgreSQL checks the OE_Update
+  ** constraint before any others, so it had to be moved.
+  **
+  ** Constraint checking code is generated in this order:
+  **   (A)  The rowid constraint
+  **   (B)  Unique index constraints that do not have OE_Replace as their
+  **        default conflict resolution strategy
+  **   (C)  Unique index that do use OE_Replace by default.
+  **
+  ** The ordering of (2) and (3) is accomplished by making sure the linked
+  ** list of indexes attached to a table puts all OE_Replace indexes last
+  ** in the list.  See sqlite3CreateIndex() for where that happens.
+  */
+  sIdxIter.eType = 0;
+  sIdxIter.i = 0;
+  sIdxIter.u.ax.aIdx = 0;  /* Silence harmless compiler warning */
+  sIdxIter.u.lx.pIdx = pTab->pIndex;
+  if( pUpsert ){
+    if( pUpsert->pUpsertTarget==0 ){
+      /* There is just on ON CONFLICT clause and it has no constraint-target */
+      assert( pUpsert->pNextUpsert==0 );
+      if( pUpsert->isDoUpdate==0 ){
+        /* A single ON CONFLICT DO NOTHING clause, without a constraint-target.
+        ** Make all unique constraint resolution be OE_Ignore */
+        overrideError = OE_Ignore;
+        pUpsert = 0;
+      }else{
+        /* A single ON CONFLICT DO UPDATE.  Make all resolutions OE_Update */
+        overrideError = OE_Update;
+      }
+    }else if( pTab->pIndex!=0 ){
+      /* Otherwise, we'll need to run the IndexListTerm array version of the
+      ** iterator to ensure that all of the ON CONFLICT conditions are
+      ** checked first and in order. */
+      int nIdx, jj;
+      u64 nByte;
+      Upsert *pTerm;
+      u8 *bUsed;
+      for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
+         assert( aRegIdx[nIdx]>0 );
+      }
+      sIdxIter.eType = 1;
+      sIdxIter.u.ax.nIdx = nIdx;
+      nByte = (sizeof(IndexListTerm)+1)*nIdx + nIdx;
+      sIdxIter.u.ax.aIdx = sqlite3DbMallocZero(db, nByte);
+      if( sIdxIter.u.ax.aIdx==0 ) return; /* OOM */
+      bUsed = (u8*)&sIdxIter.u.ax.aIdx[nIdx];
+      pUpsert->pToFree = sIdxIter.u.ax.aIdx;
+      for(i=0, pTerm=pUpsert; pTerm; pTerm=pTerm->pNextUpsert){
+        if( pTerm->pUpsertTarget==0 ) break;
+        if( pTerm->pUpsertIdx==0 ) continue;  /* Skip ON CONFLICT for the IPK */
+        jj = 0;
+        pIdx = pTab->pIndex;
+        while( ALWAYS(pIdx!=0) && pIdx!=pTerm->pUpsertIdx ){
+           pIdx = pIdx->pNext;
+           jj++;
+        }
+        if( bUsed[jj] ) continue; /* Duplicate ON CONFLICT clause ignored */
+        bUsed[jj] = 1;
+        sIdxIter.u.ax.aIdx[i].p = pIdx;
+        sIdxIter.u.ax.aIdx[i].ix = jj;
+        i++;
+      }
+      for(jj=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, jj++){
+        if( bUsed[jj] ) continue;
+        sIdxIter.u.ax.aIdx[i].p = pIdx;
+        sIdxIter.u.ax.aIdx[i].ix = jj;
+        i++;
+      }
+      assert( i==nIdx );
+    }
+  }
+
+  /* Determine if it is possible that triggers (either explicitly coded
+  ** triggers or FK resolution actions) might run as a result of deletes
+  ** that happen when OE_Replace conflict resolution occurs. (Call these
+  ** "replace triggers".)  If any replace triggers run, we will need to
+  ** recheck all of the uniqueness constraints after they have all run.
+  ** But on the recheck, the resolution is OE_Abort instead of OE_Replace.
+  **
+  ** If replace triggers are a possibility, then
+  **
+  **   (1) Allocate register regTrigCnt and initialize it to zero.
+  **       That register will count the number of replace triggers that
+  **       fire.  Constraint recheck only occurs if the number is positive.
+  **   (2) Initialize pTrigger to the list of all DELETE triggers on pTab.
+  **   (3) Initialize addrRecheck and lblRecheckOk
+  **
+  ** The uniqueness rechecking code will create a series of tests to run
+  ** in a second pass.  The addrRecheck and lblRecheckOk variables are
+  ** used to link together these tests which are separated from each other
+  ** in the generate bytecode.
+  */
+  if( (db->flags & (SQLITE_RecTriggers|SQLITE_ForeignKeys))==0 ){
+    /* There are not DELETE triggers nor FK constraints.  No constraint
+    ** rechecks are needed. */
+    pTrigger = 0;
+    regTrigCnt = 0;
+  }else{
+    if( db->flags&SQLITE_RecTriggers ){
+      pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
+      regTrigCnt = pTrigger!=0 || sqlite3FkRequired(pParse, pTab, 0, 0);
+    }else{
+      pTrigger = 0;
+      regTrigCnt = sqlite3FkRequired(pParse, pTab, 0, 0);
+    }
+    if( regTrigCnt ){
+      /* Replace triggers might exist.  Allocate the counter and
+      ** initialize it to zero. */
+      regTrigCnt = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, regTrigCnt);
+      VdbeComment((v, "trigger count"));
+      lblRecheckOk = sqlite3VdbeMakeLabel(pParse);
+      addrRecheck = lblRecheckOk;
+    }
+  }
+
+  /* If rowid is changing, make sure the new rowid does not previously
+  ** exist in the table.
+  */
+  if( pkChng && pPk==0 ){
+    int addrRowidOk = sqlite3VdbeMakeLabel(pParse);
+
+    /* Figure out what action to take in case of a rowid collision */
+    onError = pTab->keyConf;
+    if( overrideError!=OE_Default ){
+      onError = overrideError;
+    }else if( onError==OE_Default ){
+      onError = OE_Abort;
+    }
+
+    /* figure out whether or not upsert applies in this case */
+    if( pUpsert ){
+      pUpsertClause = sqlite3UpsertOfIndex(pUpsert,0);
+      if( pUpsertClause!=0 ){
+        if( pUpsertClause->isDoUpdate==0 ){
+          onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
+        }else{
+          onError = OE_Update;  /* DO UPDATE */
+        }
+      }
+      if( pUpsertClause!=pUpsert ){
+        /* The first ON CONFLICT clause has a conflict target other than
+        ** the IPK.  We have to jump ahead to that first ON CONFLICT clause
+        ** and then come back here and deal with the IPK afterwards */
+        upsertIpkDelay = sqlite3VdbeAddOp0(v, OP_Goto);
+      }
+    }
+
+    /* If the response to a rowid conflict is REPLACE but the response
+    ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
+    ** to defer the running of the rowid conflict checking until after
+    ** the UNIQUE constraints have run.
+    */
+    if( onError==OE_Replace      /* IPK rule is REPLACE */
+     && onError!=overrideError   /* Rules for other constraints are different */
+     && pTab->pIndex             /* There exist other constraints */
+     && !upsertIpkDelay          /* IPK check already deferred by UPSERT */
+    ){
+      ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
+      VdbeComment((v, "defer IPK REPLACE until last"));
+    }
+
+    if( isUpdate ){
+      /* pkChng!=0 does not mean that the rowid has changed, only that
+      ** it might have changed.  Skip the conflict logic below if the rowid
+      ** is unchanged. */
+      sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
+      sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+      VdbeCoverage(v);
+    }
+
+    /* Check to see if the new rowid already exists in the table.  Skip
+    ** the following conflict logic if it does not. */
+    VdbeNoopComment((v, "uniqueness check for ROWID"));
+    sqlite3VdbeVerifyAbortable(v, onError);
+    sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
+    VdbeCoverage(v);
+
+    switch( onError ){
+      default: {
+        onError = OE_Abort;
+        /* no break */ deliberate_fall_through
+      }
+      case OE_Rollback:
+      case OE_Abort:
+      case OE_Fail: {
+        testcase( onError==OE_Rollback );
+        testcase( onError==OE_Abort );
+        testcase( onError==OE_Fail );
+        sqlite3RowidConstraint(pParse, onError, pTab);
+        break;
+      }
+      case OE_Replace: {
+        /* If there are DELETE triggers on this table and the
+        ** recursive-triggers flag is set, call GenerateRowDelete() to
+        ** remove the conflicting row from the table. This will fire
+        ** the triggers and remove both the table and index b-tree entries.
+        **
+        ** Otherwise, if there are no triggers or the recursive-triggers
+        ** flag is not set, but the table has one or more indexes, call
+        ** GenerateRowIndexDelete(). This removes the index b-tree entries
+        ** only. The table b-tree entry will be replaced by the new entry
+        ** when it is inserted.
+        **
+        ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
+        ** also invoke MultiWrite() to indicate that this VDBE may require
+        ** statement rollback (if the statement is aborted after the delete
+        ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
+        ** but being more selective here allows statements like:
+        **
+        **   REPLACE INTO t(rowid) VALUES($newrowid)
+        **
+        ** to run without a statement journal if there are no indexes on the
+        ** table.
+        */
+        if( regTrigCnt ){
+          sqlite3MultiWrite(pParse);
+          sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
+                                   regNewData, 1, 0, OE_Replace, 1, -1);
+          sqlite3VdbeAddOp2(v, OP_AddImm, regTrigCnt, 1); /* incr trigger cnt */
+          nReplaceTrig++;
+        }else{
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+          assert( HasRowid(pTab) );
+          /* This OP_Delete opcode fires the pre-update-hook only. It does
+          ** not modify the b-tree. It is more efficient to let the coming
+          ** OP_Insert replace the existing entry than it is to delete the
+          ** existing entry and then insert a new one. */
+          sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, OPFLAG_ISNOOP);
+          sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+          if( pTab->pIndex ){
+            sqlite3MultiWrite(pParse);
+            sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,-1);
+          }
+        }
+        seenReplace = 1;
+        break;
+      }
+#ifndef SQLITE_OMIT_UPSERT
+      case OE_Update: {
+        sqlite3UpsertDoUpdate(pParse, pUpsert, pTab, 0, iDataCur);
+        /* no break */ deliberate_fall_through
+      }
+#endif
+      case OE_Ignore: {
+        testcase( onError==OE_Ignore );
+        sqlite3VdbeGoto(v, ignoreDest);
+        break;
+      }
+    }
+    sqlite3VdbeResolveLabel(v, addrRowidOk);
+    if( pUpsert && pUpsertClause!=pUpsert ){
+      upsertIpkReturn = sqlite3VdbeAddOp0(v, OP_Goto);
+    }else if( ipkTop ){
+      ipkBottom = sqlite3VdbeAddOp0(v, OP_Goto);
+      sqlite3VdbeJumpHere(v, ipkTop-1);
+    }
+  }
+
+  /* Test all UNIQUE constraints by creating entries for each UNIQUE
+  ** index and making sure that duplicate entries do not already exist.
+  ** Compute the revised record entries for indices as we go.
+  **
+  ** This loop also handles the case of the PRIMARY KEY index for a
+  ** WITHOUT ROWID table.
+  */
+  for(pIdx = indexIteratorFirst(&sIdxIter, &ix);
+      pIdx;
+      pIdx = indexIteratorNext(&sIdxIter, &ix)
+  ){
+    int regIdx;          /* Range of registers holding content for pIdx */
+    int regR;            /* Range of registers holding conflicting PK */
+    int iThisCur;        /* Cursor for this UNIQUE index */
+    int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */
+    int addrConflictCk;  /* First opcode in the conflict check logic */
+
+    if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */
+    if( pUpsert ){
+      pUpsertClause = sqlite3UpsertOfIndex(pUpsert, pIdx);
+      if( upsertIpkDelay && pUpsertClause==pUpsert ){
+        sqlite3VdbeJumpHere(v, upsertIpkDelay);
+      }
+    }
+    addrUniqueOk = sqlite3VdbeMakeLabel(pParse);
+    if( bAffinityDone==0 ){
+      sqlite3TableAffinity(v, pTab, regNewData+1);
+      bAffinityDone = 1;
+    }
+    VdbeNoopComment((v, "prep index %s", pIdx->zName));
+    iThisCur = iIdxCur+ix;
+
+
+    /* Skip partial indices for which the WHERE clause is not true */
+    if( pIdx->pPartIdxWhere ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, aRegIdx[ix]);
+      pParse->iSelfTab = -(regNewData+1);
+      sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, addrUniqueOk,
+                            SQLITE_JUMPIFNULL);
+      pParse->iSelfTab = 0;
+    }
+
+    /* Create a record for this index entry as it should appear after
+    ** the insert or update.  Store that record in the aRegIdx[ix] register
+    */
+    regIdx = aRegIdx[ix]+1;
+    for(i=0; i<pIdx->nColumn; i++){
+      int iField = pIdx->aiColumn[i];
+      int x;
+      if( iField==XN_EXPR ){
+        pParse->iSelfTab = -(regNewData+1);
+        sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[i].pExpr, regIdx+i);
+        pParse->iSelfTab = 0;
+        VdbeComment((v, "%s column %d", pIdx->zName, i));
+      }else if( iField==XN_ROWID || iField==pTab->iPKey ){
+        x = regNewData;
+        sqlite3VdbeAddOp2(v, OP_IntCopy, x, regIdx+i);
+        VdbeComment((v, "rowid"));
+      }else{
+        testcase( sqlite3TableColumnToStorage(pTab, iField)!=iField );
+        x = sqlite3TableColumnToStorage(pTab, iField) + regNewData + 1;
+        sqlite3VdbeAddOp2(v, OP_SCopy, x, regIdx+i);
+        VdbeComment((v, "%s", pTab->aCol[iField].zCnName));
+      }
+    }
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn, aRegIdx[ix]);
+    VdbeComment((v, "for %s", pIdx->zName));
+#ifdef SQLITE_ENABLE_NULL_TRIM
+    if( pIdx->idxType==SQLITE_IDXTYPE_PRIMARYKEY ){
+      sqlite3SetMakeRecordP5(v, pIdx->pTable);
+    }
+#endif
+    sqlite3VdbeReleaseRegisters(pParse, regIdx, pIdx->nColumn, 0, 0);
+
+    /* In an UPDATE operation, if this index is the PRIMARY KEY index
+    ** of a WITHOUT ROWID table and there has been no change the
+    ** primary key, then no collision is possible.  The collision detection
+    ** logic below can all be skipped. */
+    if( isUpdate && pPk==pIdx && pkChng==0 ){
+      sqlite3VdbeResolveLabel(v, addrUniqueOk);
+      continue;
+    }
+
+    /* Find out what action to take in case there is a uniqueness conflict */
+    onError = pIdx->onError;
+    if( onError==OE_None ){
+      sqlite3VdbeResolveLabel(v, addrUniqueOk);
+      continue;  /* pIdx is not a UNIQUE index */
+    }
+    if( overrideError!=OE_Default ){
+      onError = overrideError;
+    }else if( onError==OE_Default ){
+      onError = OE_Abort;
+    }
+
+    /* Figure out if the upsert clause applies to this index */
+    if( pUpsertClause ){
+      if( pUpsertClause->isDoUpdate==0 ){
+        onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
+      }else{
+        onError = OE_Update;  /* DO UPDATE */
+      }
+    }
+
+    /* Collision detection may be omitted if all of the following are true:
+    **   (1) The conflict resolution algorithm is REPLACE
+    **   (2) The table is a WITHOUT ROWID table
+    **   (3) There are no secondary indexes on the table
+    **   (4) No delete triggers need to be fired if there is a conflict
+    **   (5) No FK constraint counters need to be updated if a conflict occurs.
+    **
+    ** This is not possible for ENABLE_PREUPDATE_HOOK builds, as the row
+    ** must be explicitly deleted in order to ensure any pre-update hook
+    ** is invoked.  */
+    assert( IsOrdinaryTable(pTab) );
+#ifndef SQLITE_ENABLE_PREUPDATE_HOOK
+    if( (ix==0 && pIdx->pNext==0)                   /* Condition 3 */
+     && pPk==pIdx                                   /* Condition 2 */
+     && onError==OE_Replace                         /* Condition 1 */
+     && ( 0==(db->flags&SQLITE_RecTriggers) ||      /* Condition 4 */
+          0==sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0))
+     && ( 0==(db->flags&SQLITE_ForeignKeys) ||      /* Condition 5 */
+         (0==pTab->u.tab.pFKey && 0==sqlite3FkReferences(pTab)))
+    ){
+      sqlite3VdbeResolveLabel(v, addrUniqueOk);
+      continue;
+    }
+#endif /* ifndef SQLITE_ENABLE_PREUPDATE_HOOK */
+
+    /* Check to see if the new index entry will be unique */
+    sqlite3VdbeVerifyAbortable(v, onError);
+    addrConflictCk =
+      sqlite3VdbeAddOp4Int(v, OP_NoConflict, iThisCur, addrUniqueOk,
+                           regIdx, pIdx->nKeyCol); VdbeCoverage(v);
+
+    /* Generate code to handle collisions */
+    regR = pIdx==pPk ? regIdx : sqlite3GetTempRange(pParse, nPkField);
+    if( isUpdate || onError==OE_Replace ){
+      if( HasRowid(pTab) ){
+        sqlite3VdbeAddOp2(v, OP_IdxRowid, iThisCur, regR);
+        /* Conflict only if the rowid of the existing index entry
+        ** is different from old-rowid */
+        if( isUpdate ){
+          sqlite3VdbeAddOp3(v, OP_Eq, regR, addrUniqueOk, regOldData);
+          sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+          VdbeCoverage(v);
+        }
+      }else{
+        int x;
+        /* Extract the PRIMARY KEY from the end of the index entry and
+        ** store it in registers regR..regR+nPk-1 */
+        if( pIdx!=pPk ){
+          for(i=0; i<pPk->nKeyCol; i++){
+            assert( pPk->aiColumn[i]>=0 );
+            x = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[i]);
+            sqlite3VdbeAddOp3(v, OP_Column, iThisCur, x, regR+i);
+            VdbeComment((v, "%s.%s", pTab->zName,
+                         pTab->aCol[pPk->aiColumn[i]].zCnName));
+          }
+        }
+        if( isUpdate ){
+          /* If currently processing the PRIMARY KEY of a WITHOUT ROWID
+          ** table, only conflict if the new PRIMARY KEY values are actually
+          ** different from the old.  See TH3 withoutrowid04.test.
+          **
+          ** For a UNIQUE index, only conflict if the PRIMARY KEY values
+          ** of the matched index row are different from the original PRIMARY
+          ** KEY values of this row before the update.  */
+          int addrJump = sqlite3VdbeCurrentAddr(v)+pPk->nKeyCol;
+          int op = OP_Ne;
+          int regCmp = (IsPrimaryKeyIndex(pIdx) ? regIdx : regR);
+
+          for(i=0; i<pPk->nKeyCol; i++){
+            char *p4 = (char*)sqlite3LocateCollSeq(pParse, pPk->azColl[i]);
+            x = pPk->aiColumn[i];
+            assert( x>=0 );
+            if( i==(pPk->nKeyCol-1) ){
+              addrJump = addrUniqueOk;
+              op = OP_Eq;
+            }
+            x = sqlite3TableColumnToStorage(pTab, x);
+            sqlite3VdbeAddOp4(v, op,
+                regOldData+1+x, addrJump, regCmp+i, p4, P4_COLLSEQ
+            );
+            sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+            VdbeCoverageIf(v, op==OP_Eq);
+            VdbeCoverageIf(v, op==OP_Ne);
+          }
+        }
+      }
+    }
+
+    /* Generate code that executes if the new index entry is not unique */
+    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
+        || onError==OE_Ignore || onError==OE_Replace || onError==OE_Update );
+    switch( onError ){
+      case OE_Rollback:
+      case OE_Abort:
+      case OE_Fail: {
+        testcase( onError==OE_Rollback );
+        testcase( onError==OE_Abort );
+        testcase( onError==OE_Fail );
+        sqlite3UniqueConstraint(pParse, onError, pIdx);
+        break;
+      }
+#ifndef SQLITE_OMIT_UPSERT
+      case OE_Update: {
+        sqlite3UpsertDoUpdate(pParse, pUpsert, pTab, pIdx, iIdxCur+ix);
+        /* no break */ deliberate_fall_through
+      }
+#endif
+      case OE_Ignore: {
+        testcase( onError==OE_Ignore );
+        sqlite3VdbeGoto(v, ignoreDest);
+        break;
+      }
+      default: {
+        int nConflictCk;   /* Number of opcodes in conflict check logic */
+
+        assert( onError==OE_Replace );
+        nConflictCk = sqlite3VdbeCurrentAddr(v) - addrConflictCk;
+        assert( nConflictCk>0 || db->mallocFailed );
+        testcase( nConflictCk<=0 );
+        testcase( nConflictCk>1 );
+        if( regTrigCnt ){
+          sqlite3MultiWrite(pParse);
+          nReplaceTrig++;
+        }
+        if( pTrigger && isUpdate ){
+          sqlite3VdbeAddOp1(v, OP_CursorLock, iDataCur);
+        }
+        sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
+            regR, nPkField, 0, OE_Replace,
+            (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
+        if( pTrigger && isUpdate ){
+          sqlite3VdbeAddOp1(v, OP_CursorUnlock, iDataCur);
+        }
+        if( regTrigCnt ){
+          int addrBypass;  /* Jump destination to bypass recheck logic */
+
+          sqlite3VdbeAddOp2(v, OP_AddImm, regTrigCnt, 1); /* incr trigger cnt */
+          addrBypass = sqlite3VdbeAddOp0(v, OP_Goto);  /* Bypass recheck */
+          VdbeComment((v, "bypass recheck"));
+
+          /* Here we insert code that will be invoked after all constraint
+          ** checks have run, if and only if one or more replace triggers
+          ** fired. */
+          sqlite3VdbeResolveLabel(v, lblRecheckOk);
+          lblRecheckOk = sqlite3VdbeMakeLabel(pParse);
+          if( pIdx->pPartIdxWhere ){
+            /* Bypass the recheck if this partial index is not defined
+            ** for the current row */
+            sqlite3VdbeAddOp2(v, OP_IsNull, regIdx-1, lblRecheckOk);
+            VdbeCoverage(v);
+          }
+          /* Copy the constraint check code from above, except change
+          ** the constraint-ok jump destination to be the address of
+          ** the next retest block */
+          while( nConflictCk>0 ){
+            VdbeOp x;    /* Conflict check opcode to copy */
+            /* The sqlite3VdbeAddOp4() call might reallocate the opcode array.
+            ** Hence, make a complete copy of the opcode, rather than using
+            ** a pointer to the opcode. */
+            x = *sqlite3VdbeGetOp(v, addrConflictCk);
+            if( x.opcode!=OP_IdxRowid ){
+              int p2;      /* New P2 value for copied conflict check opcode */
+              const char *zP4;
+              if( sqlite3OpcodeProperty[x.opcode]&OPFLG_JUMP ){
+                p2 = lblRecheckOk;
+              }else{
+                p2 = x.p2;
+              }
+              zP4 = x.p4type==P4_INT32 ? SQLITE_INT_TO_PTR(x.p4.i) : x.p4.z;
+              sqlite3VdbeAddOp4(v, x.opcode, x.p1, p2, x.p3, zP4, x.p4type);
+              sqlite3VdbeChangeP5(v, x.p5);
+              VdbeCoverageIf(v, p2!=x.p2);
+            }
+            nConflictCk--;
+            addrConflictCk++;
+          }
+          /* If the retest fails, issue an abort */
+          sqlite3UniqueConstraint(pParse, OE_Abort, pIdx);
+
+          sqlite3VdbeJumpHere(v, addrBypass); /* Terminate the recheck bypass */
+        }
+        seenReplace = 1;
+        break;
+      }
+    }
+    sqlite3VdbeResolveLabel(v, addrUniqueOk);
+    if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);
+    if( pUpsertClause
+     && upsertIpkReturn
+     && sqlite3UpsertNextIsIPK(pUpsertClause)
+    ){
+      sqlite3VdbeGoto(v, upsertIpkDelay+1);
+      sqlite3VdbeJumpHere(v, upsertIpkReturn);
+      upsertIpkReturn = 0;
+    }
+  }
+
+  /* If the IPK constraint is a REPLACE, run it last */
+  if( ipkTop ){
+    sqlite3VdbeGoto(v, ipkTop);
+    VdbeComment((v, "Do IPK REPLACE"));
+    assert( ipkBottom>0 );
+    sqlite3VdbeJumpHere(v, ipkBottom);
+  }
+
+  /* Recheck all uniqueness constraints after replace triggers have run */
+  testcase( regTrigCnt!=0 && nReplaceTrig==0 );
+  assert( regTrigCnt!=0 || nReplaceTrig==0 );
+  if( nReplaceTrig ){
+    sqlite3VdbeAddOp2(v, OP_IfNot, regTrigCnt, lblRecheckOk);VdbeCoverage(v);
+    if( !pPk ){
+      if( isUpdate ){
+        sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRecheck, regOldData);
+        sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+        VdbeCoverage(v);
+      }
+      sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRecheck, regNewData);
+      VdbeCoverage(v);
+      sqlite3RowidConstraint(pParse, OE_Abort, pTab);
+    }else{
+      sqlite3VdbeGoto(v, addrRecheck);
+    }
+    sqlite3VdbeResolveLabel(v, lblRecheckOk);
+  }
+
+  /* Generate the table record */
+  if( HasRowid(pTab) ){
+    int regRec = aRegIdx[ix];
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regNewData+1, pTab->nNVCol, regRec);
+    sqlite3SetMakeRecordP5(v, pTab);
+    if( !bAffinityDone ){
+      sqlite3TableAffinity(v, pTab, 0);
+    }
+  }
+
+  *pbMayReplace = seenReplace;
+  VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
+}
+
+#ifdef SQLITE_ENABLE_NULL_TRIM
+/*
+** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
+** to be the number of columns in table pTab that must not be NULL-trimmed.
+**
+** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
+*/
+SQLITE_PRIVATE void sqlite3SetMakeRecordP5(Vdbe *v, Table *pTab){
+  u16 i;
+
+  /* Records with omitted columns are only allowed for schema format
+  ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
+  if( pTab->pSchema->file_format<2 ) return;
+
+  for(i=pTab->nCol-1; i>0; i--){
+    if( pTab->aCol[i].iDflt!=0 ) break;
+    if( pTab->aCol[i].colFlags & COLFLAG_PRIMKEY ) break;
+  }
+  sqlite3VdbeChangeP5(v, i+1);
+}
+#endif
+
+/*
+** Table pTab is a WITHOUT ROWID table that is being written to. The cursor
+** number is iCur, and register regData contains the new record for the
+** PK index. This function adds code to invoke the pre-update hook,
+** if one is registered.
+*/
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+static void codeWithoutRowidPreupdate(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being updated */
+  int iCur,                       /* Cursor number for table */
+  int regData                     /* Data containing new record */
+){
+  Vdbe *v = pParse->pVdbe;
+  int r = sqlite3GetTempReg(pParse);
+  assert( !HasRowid(pTab) );
+  assert( 0==(pParse->db->mDbFlags & DBFLAG_Vacuum) || CORRUPT_DB );
+  sqlite3VdbeAddOp2(v, OP_Integer, 0, r);
+  sqlite3VdbeAddOp4(v, OP_Insert, iCur, regData, r, (char*)pTab, P4_TABLE);
+  sqlite3VdbeChangeP5(v, OPFLAG_ISNOOP);
+  sqlite3ReleaseTempReg(pParse, r);
+}
+#else
+# define codeWithoutRowidPreupdate(a,b,c,d)
+#endif
+
+/*
+** This routine generates code to finish the INSERT or UPDATE operation
+** that was started by a prior call to sqlite3GenerateConstraintChecks.
+** A consecutive range of registers starting at regNewData contains the
+** rowid and the content to be inserted.
+**
+** The arguments to this routine should be the same as the first six
+** arguments to sqlite3GenerateConstraintChecks.
+*/
+SQLITE_PRIVATE void sqlite3CompleteInsertion(
+  Parse *pParse,      /* The parser context */
+  Table *pTab,        /* the table into which we are inserting */
+  int iDataCur,       /* Cursor of the canonical data source */
+  int iIdxCur,        /* First index cursor */
+  int regNewData,     /* Range of content */
+  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
+  int update_flags,   /* True for UPDATE, False for INSERT */
+  int appendBias,     /* True if this is likely to be an append */
+  int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
+){
+  Vdbe *v;            /* Prepared statements under construction */
+  Index *pIdx;        /* An index being inserted or updated */
+  u8 pik_flags;       /* flag values passed to the btree insert */
+  int i;              /* Loop counter */
+
+  assert( update_flags==0
+       || update_flags==OPFLAG_ISUPDATE
+       || update_flags==(OPFLAG_ISUPDATE|OPFLAG_SAVEPOSITION)
+  );
+
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  assert( !IsView(pTab) );  /* This table is not a VIEW */
+  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+    /* All REPLACE indexes are at the end of the list */
+    assert( pIdx->onError!=OE_Replace
+         || pIdx->pNext==0
+         || pIdx->pNext->onError==OE_Replace );
+    if( aRegIdx[i]==0 ) continue;
+    if( pIdx->pPartIdxWhere ){
+      sqlite3VdbeAddOp2(v, OP_IsNull, aRegIdx[i], sqlite3VdbeCurrentAddr(v)+2);
+      VdbeCoverage(v);
+    }
+    pik_flags = (useSeekResult ? OPFLAG_USESEEKRESULT : 0);
+    if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
+      pik_flags |= OPFLAG_NCHANGE;
+      pik_flags |= (update_flags & OPFLAG_SAVEPOSITION);
+      if( update_flags==0 ){
+        codeWithoutRowidPreupdate(pParse, pTab, iIdxCur+i, aRegIdx[i]);
+      }
+    }
+    sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iIdxCur+i, aRegIdx[i],
+                         aRegIdx[i]+1,
+                         pIdx->uniqNotNull ? pIdx->nKeyCol: pIdx->nColumn);
+    sqlite3VdbeChangeP5(v, pik_flags);
+  }
+  if( !HasRowid(pTab) ) return;
+  if( pParse->nested ){
+    pik_flags = 0;
+  }else{
+    pik_flags = OPFLAG_NCHANGE;
+    pik_flags |= (update_flags?update_flags:OPFLAG_LASTROWID);
+  }
+  if( appendBias ){
+    pik_flags |= OPFLAG_APPEND;
+  }
+  if( useSeekResult ){
+    pik_flags |= OPFLAG_USESEEKRESULT;
+  }
+  sqlite3VdbeAddOp3(v, OP_Insert, iDataCur, aRegIdx[i], regNewData);
+  if( !pParse->nested ){
+    sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+  }
+  sqlite3VdbeChangeP5(v, pik_flags);
+}
+
+/*
+** Allocate cursors for the pTab table and all its indices and generate
+** code to open and initialized those cursors.
+**
+** The cursor for the object that contains the complete data (normally
+** the table itself, but the PRIMARY KEY index in the case of a WITHOUT
+** ROWID table) is returned in *piDataCur.  The first index cursor is
+** returned in *piIdxCur.  The number of indices is returned.
+**
+** Use iBase as the first cursor (either the *piDataCur for rowid tables
+** or the first index for WITHOUT ROWID tables) if it is non-negative.
+** If iBase is negative, then allocate the next available cursor.
+**
+** For a rowid table, *piDataCur will be exactly one less than *piIdxCur.
+** For a WITHOUT ROWID table, *piDataCur will be somewhere in the range
+** of *piIdxCurs, depending on where the PRIMARY KEY index appears on the
+** pTab->pIndex list.
+**
+** If pTab is a virtual table, then this routine is a no-op and the
+** *piDataCur and *piIdxCur values are left uninitialized.
+*/
+SQLITE_PRIVATE int sqlite3OpenTableAndIndices(
+  Parse *pParse,   /* Parsing context */
+  Table *pTab,     /* Table to be opened */
+  int op,          /* OP_OpenRead or OP_OpenWrite */
+  u8 p5,           /* P5 value for OP_Open* opcodes (except on WITHOUT ROWID) */
+  int iBase,       /* Use this for the table cursor, if there is one */
+  u8 *aToOpen,     /* If not NULL: boolean for each table and index */
+  int *piDataCur,  /* Write the database source cursor number here */
+  int *piIdxCur    /* Write the first index cursor number here */
+){
+  int i;
+  int iDb;
+  int iDataCur;
+  Index *pIdx;
+  Vdbe *v;
+
+  assert( op==OP_OpenRead || op==OP_OpenWrite );
+  assert( op==OP_OpenWrite || p5==0 );
+  assert( piDataCur!=0 );
+  assert( piIdxCur!=0 );
+  if( IsVirtual(pTab) ){
+    /* This routine is a no-op for virtual tables. Leave the output
+    ** variables *piDataCur and *piIdxCur set to illegal cursor numbers
+    ** for improved error detection. */
+    *piDataCur = *piIdxCur = -999;
+    return 0;
+  }
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  if( iBase<0 ) iBase = pParse->nTab;
+  iDataCur = iBase++;
+  *piDataCur = iDataCur;
+  if( HasRowid(pTab) && (aToOpen==0 || aToOpen[0]) ){
+    sqlite3OpenTable(pParse, iDataCur, iDb, pTab, op);
+  }else if( pParse->db->noSharedCache==0 ){
+    sqlite3TableLock(pParse, iDb, pTab->tnum, op==OP_OpenWrite, pTab->zName);
+  }
+  *piIdxCur = iBase;
+  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+    int iIdxCur = iBase++;
+    assert( pIdx->pSchema==pTab->pSchema );
+    if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
+      *piDataCur = iIdxCur;
+      p5 = 0;
+    }
+    if( aToOpen==0 || aToOpen[i+1] ){
+      sqlite3VdbeAddOp3(v, op, iIdxCur, pIdx->tnum, iDb);
+      sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+      sqlite3VdbeChangeP5(v, p5);
+      VdbeComment((v, "%s", pIdx->zName));
+    }
+  }
+  if( iBase>pParse->nTab ) pParse->nTab = iBase;
+  return i;
+}
+
+
+#ifdef SQLITE_TEST
+/*
+** The following global variable is incremented whenever the
+** transfer optimization is used.  This is used for testing
+** purposes only - to make sure the transfer optimization really
+** is happening when it is supposed to.
+*/
+SQLITE_API int sqlite3_xferopt_count;
+#endif /* SQLITE_TEST */
+
+
+#ifndef SQLITE_OMIT_XFER_OPT
+/*
+** Check to see if index pSrc is compatible as a source of data
+** for index pDest in an insert transfer optimization.  The rules
+** for a compatible index:
+**
+**    *   The index is over the same set of columns
+**    *   The same DESC and ASC markings occurs on all columns
+**    *   The same onError processing (OE_Abort, OE_Ignore, etc)
+**    *   The same collating sequence on each column
+**    *   The index has the exact same WHERE clause
+*/
+static int xferCompatibleIndex(Index *pDest, Index *pSrc){
+  int i;
+  assert( pDest && pSrc );
+  assert( pDest->pTable!=pSrc->pTable );
+  if( pDest->nKeyCol!=pSrc->nKeyCol || pDest->nColumn!=pSrc->nColumn ){
+    return 0;   /* Different number of columns */
+  }
+  if( pDest->onError!=pSrc->onError ){
+    return 0;   /* Different conflict resolution strategies */
+  }
+  for(i=0; i<pSrc->nKeyCol; i++){
+    if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
+      return 0;   /* Different columns indexed */
+    }
+    if( pSrc->aiColumn[i]==XN_EXPR ){
+      assert( pSrc->aColExpr!=0 && pDest->aColExpr!=0 );
+      if( sqlite3ExprCompare(0, pSrc->aColExpr->a[i].pExpr,
+                             pDest->aColExpr->a[i].pExpr, -1)!=0 ){
+        return 0;   /* Different expressions in the index */
+      }
+    }
+    if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
+      return 0;   /* Different sort orders */
+    }
+    if( sqlite3_stricmp(pSrc->azColl[i],pDest->azColl[i])!=0 ){
+      return 0;   /* Different collating sequences */
+    }
+  }
+  if( sqlite3ExprCompare(0, pSrc->pPartIdxWhere, pDest->pPartIdxWhere, -1) ){
+    return 0;     /* Different WHERE clauses */
+  }
+
+  /* If no test above fails then the indices must be compatible */
+  return 1;
+}
+
+/*
+** Attempt the transfer optimization on INSERTs of the form
+**
+**     INSERT INTO tab1 SELECT * FROM tab2;
+**
+** The xfer optimization transfers raw records from tab2 over to tab1.
+** Columns are not decoded and reassembled, which greatly improves
+** performance.  Raw index records are transferred in the same way.
+**
+** The xfer optimization is only attempted if tab1 and tab2 are compatible.
+** There are lots of rules for determining compatibility - see comments
+** embedded in the code for details.
+**
+** This routine returns TRUE if the optimization is guaranteed to be used.
+** Sometimes the xfer optimization will only work if the destination table
+** is empty - a factor that can only be determined at run-time.  In that
+** case, this routine generates code for the xfer optimization but also
+** does a test to see if the destination table is empty and jumps over the
+** xfer optimization code if the test fails.  In that case, this routine
+** returns FALSE so that the caller will know to go ahead and generate
+** an unoptimized transfer.  This routine also returns FALSE if there
+** is no chance that the xfer optimization can be applied.
+**
+** This optimization is particularly useful at making VACUUM run faster.
+*/
+static int xferOptimization(
+  Parse *pParse,        /* Parser context */
+  Table *pDest,         /* The table we are inserting into */
+  Select *pSelect,      /* A SELECT statement to use as the data source */
+  int onError,          /* How to handle constraint errors */
+  int iDbDest           /* The database of pDest */
+){
+  sqlite3 *db = pParse->db;
+  ExprList *pEList;                /* The result set of the SELECT */
+  Table *pSrc;                     /* The table in the FROM clause of SELECT */
+  Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
+  SrcItem *pItem;                  /* An element of pSelect->pSrc */
+  int i;                           /* Loop counter */
+  int iDbSrc;                      /* The database of pSrc */
+  int iSrc, iDest;                 /* Cursors from source and destination */
+  int addr1, addr2;                /* Loop addresses */
+  int emptyDestTest = 0;           /* Address of test for empty pDest */
+  int emptySrcTest = 0;            /* Address of test for empty pSrc */
+  Vdbe *v;                         /* The VDBE we are building */
+  int regAutoinc;                  /* Memory register used by AUTOINC */
+  int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */
+  int regData, regRowid;           /* Registers holding data and rowid */
+
+  assert( pSelect!=0 );
+  if( pParse->pWith || pSelect->pWith ){
+    /* Do not attempt to process this query if there are an WITH clauses
+    ** attached to it. Proceeding may generate a false "no such table: xxx"
+    ** error if pSelect reads from a CTE named "xxx".  */
+    return 0;
+  }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pDest) ){
+    return 0;   /* tab1 must not be a virtual table */
+  }
+#endif
+  if( onError==OE_Default ){
+    if( pDest->iPKey>=0 ) onError = pDest->keyConf;
+    if( onError==OE_Default ) onError = OE_Abort;
+  }
+  assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
+  if( pSelect->pSrc->nSrc!=1 ){
+    return 0;   /* FROM clause must have exactly one term */
+  }
+  if( pSelect->pSrc->a[0].fg.isSubquery ){
+    return 0;   /* FROM clause cannot contain a subquery */
+  }
+  if( pSelect->pWhere ){
+    return 0;   /* SELECT may not have a WHERE clause */
+  }
+  if( pSelect->pOrderBy ){
+    return 0;   /* SELECT may not have an ORDER BY clause */
+  }
+  /* Do not need to test for a HAVING clause.  If HAVING is present but
+  ** there is no ORDER BY, we will get an error. */
+  if( pSelect->pGroupBy ){
+    return 0;   /* SELECT may not have a GROUP BY clause */
+  }
+  if( pSelect->pLimit ){
+    return 0;   /* SELECT may not have a LIMIT clause */
+  }
+  if( pSelect->pPrior ){
+    return 0;   /* SELECT may not be a compound query */
+  }
+  if( pSelect->selFlags & SF_Distinct ){
+    return 0;   /* SELECT may not be DISTINCT */
+  }
+  pEList = pSelect->pEList;
+  assert( pEList!=0 );
+  if( pEList->nExpr!=1 ){
+    return 0;   /* The result set must have exactly one column */
+  }
+  assert( pEList->a[0].pExpr );
+  if( pEList->a[0].pExpr->op!=TK_ASTERISK ){
+    return 0;   /* The result set must be the special operator "*" */
+  }
+
+  /* At this point we have established that the statement is of the
+  ** correct syntactic form to participate in this optimization.  Now
+  ** we have to check the semantics.
+  */
+  pItem = pSelect->pSrc->a;
+  pSrc = sqlite3LocateTableItem(pParse, 0, pItem);
+  if( pSrc==0 ){
+    return 0;   /* FROM clause does not contain a real table */
+  }
+  if( pSrc->tnum==pDest->tnum && pSrc->pSchema==pDest->pSchema ){
+    testcase( pSrc!=pDest ); /* Possible due to bad sqlite_schema.rootpage */
+    return 0;   /* tab1 and tab2 may not be the same table */
+  }
+  if( HasRowid(pDest)!=HasRowid(pSrc) ){
+    return 0;   /* source and destination must both be WITHOUT ROWID or not */
+  }
+  if( !IsOrdinaryTable(pSrc) ){
+    return 0;   /* tab2 may not be a view or virtual table */
+  }
+  if( pDest->nCol!=pSrc->nCol ){
+    return 0;   /* Number of columns must be the same in tab1 and tab2 */
+  }
+  if( pDest->iPKey!=pSrc->iPKey ){
+    return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
+  }
+  if( (pDest->tabFlags & TF_Strict)!=0 && (pSrc->tabFlags & TF_Strict)==0 ){
+    return 0;   /* Cannot feed from a non-strict into a strict table */
+  }
+  for(i=0; i<pDest->nCol; i++){
+    Column *pDestCol = &pDest->aCol[i];
+    Column *pSrcCol = &pSrc->aCol[i];
+#ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
+    if( (db->mDbFlags & DBFLAG_Vacuum)==0
+     && (pDestCol->colFlags | pSrcCol->colFlags) & COLFLAG_HIDDEN
+    ){
+      return 0;    /* Neither table may have __hidden__ columns */
+    }
+#endif
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    /* Even if tables t1 and t2 have identical schemas, if they contain
+    ** generated columns, then this statement is semantically incorrect:
+    **
+    **     INSERT INTO t2 SELECT * FROM t1;
+    **
+    ** The reason is that generated column values are returned by the
+    ** the SELECT statement on the right but the INSERT statement on the
+    ** left wants them to be omitted.
+    **
+    ** Nevertheless, this is a useful notational shorthand to tell SQLite
+    ** to do a bulk transfer all of the content from t1 over to t2.
+    **
+    ** We could, in theory, disable this (except for internal use by the
+    ** VACUUM command where it is actually needed).  But why do that?  It
+    ** seems harmless enough, and provides a useful service.
+    */
+    if( (pDestCol->colFlags & COLFLAG_GENERATED) !=
+        (pSrcCol->colFlags & COLFLAG_GENERATED) ){
+      return 0;    /* Both columns have the same generated-column type */
+    }
+    /* But the transfer is only allowed if both the source and destination
+    ** tables have the exact same expressions for generated columns.
+    ** This requirement could be relaxed for VIRTUAL columns, I suppose.
+    */
+    if( (pDestCol->colFlags & COLFLAG_GENERATED)!=0 ){
+      if( sqlite3ExprCompare(0,
+             sqlite3ColumnExpr(pSrc, pSrcCol),
+             sqlite3ColumnExpr(pDest, pDestCol), -1)!=0 ){
+        testcase( pDestCol->colFlags & COLFLAG_VIRTUAL );
+        testcase( pDestCol->colFlags & COLFLAG_STORED );
+        return 0;  /* Different generator expressions */
+      }
+    }
+#endif
+    if( pDestCol->affinity!=pSrcCol->affinity ){
+      return 0;    /* Affinity must be the same on all columns */
+    }
+    if( sqlite3_stricmp(sqlite3ColumnColl(pDestCol),
+                        sqlite3ColumnColl(pSrcCol))!=0 ){
+      return 0;    /* Collating sequence must be the same on all columns */
+    }
+    if( pDestCol->notNull && !pSrcCol->notNull ){
+      return 0;    /* tab2 must be NOT NULL if tab1 is */
+    }
+    /* Default values for second and subsequent columns need to match. */
+    if( (pDestCol->colFlags & COLFLAG_GENERATED)==0 && i>0 ){
+      Expr *pDestExpr = sqlite3ColumnExpr(pDest, pDestCol);
+      Expr *pSrcExpr = sqlite3ColumnExpr(pSrc, pSrcCol);
+      assert( pDestExpr==0 || pDestExpr->op==TK_SPAN );
+      assert( pDestExpr==0 || !ExprHasProperty(pDestExpr, EP_IntValue) );
+      assert( pSrcExpr==0 || pSrcExpr->op==TK_SPAN );
+      assert( pSrcExpr==0 || !ExprHasProperty(pSrcExpr, EP_IntValue) );
+      if( (pDestExpr==0)!=(pSrcExpr==0)
+       || (pDestExpr!=0 && strcmp(pDestExpr->u.zToken,
+                                       pSrcExpr->u.zToken)!=0)
+      ){
+        return 0;    /* Default values must be the same for all columns */
+      }
+    }
+  }
+  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
+    if( IsUniqueIndex(pDestIdx) ){
+      destHasUniqueIdx = 1;
+    }
+    for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
+      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
+    }
+    if( pSrcIdx==0 ){
+      return 0;    /* pDestIdx has no corresponding index in pSrc */
+    }
+    if( pSrcIdx->tnum==pDestIdx->tnum && pSrc->pSchema==pDest->pSchema
+         && sqlite3FaultSim(411)==SQLITE_OK ){
+      /* The sqlite3FaultSim() call allows this corruption test to be
+      ** bypassed during testing, in order to exercise other corruption tests
+      ** further downstream. */
+      return 0;   /* Corrupt schema - two indexes on the same btree */
+    }
+  }
+#ifndef SQLITE_OMIT_CHECK
+  if( pDest->pCheck
+   && (db->mDbFlags & DBFLAG_Vacuum)==0
+   && sqlite3ExprListCompare(pSrc->pCheck,pDest->pCheck,-1)
+  ){
+    return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
+  }
+#endif
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  /* Disallow the transfer optimization if the destination table contains
+  ** any foreign key constraints.  This is more restrictive than necessary.
+  ** But the main beneficiary of the transfer optimization is the VACUUM
+  ** command, and the VACUUM command disables foreign key constraints.  So
+  ** the extra complication to make this rule less restrictive is probably
+  ** not worth the effort.  Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
+  */
+  assert( IsOrdinaryTable(pDest) );
+  if( (db->flags & SQLITE_ForeignKeys)!=0 && pDest->u.tab.pFKey!=0 ){
+    return 0;
+  }
+#endif
+  if( (db->flags & SQLITE_CountRows)!=0 ){
+    return 0;  /* xfer opt does not play well with PRAGMA count_changes */
+  }
+
+  /* If we get this far, it means that the xfer optimization is at
+  ** least a possibility, though it might only work if the destination
+  ** table (tab1) is initially empty.
+  */
+#ifdef SQLITE_TEST
+  sqlite3_xferopt_count++;
+#endif
+  iDbSrc = sqlite3SchemaToIndex(db, pSrc->pSchema);
+  v = sqlite3GetVdbe(pParse);
+  sqlite3CodeVerifySchema(pParse, iDbSrc);
+  iSrc = pParse->nTab++;
+  iDest = pParse->nTab++;
+  regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
+  regData = sqlite3GetTempReg(pParse);
+  sqlite3VdbeAddOp2(v, OP_Null, 0, regData);
+  regRowid = sqlite3GetTempReg(pParse);
+  sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
+  assert( HasRowid(pDest) || destHasUniqueIdx );
+  if( (db->mDbFlags & DBFLAG_Vacuum)==0 && (
+      (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
+   || destHasUniqueIdx                              /* (2) */
+   || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
+  )){
+    /* In some circumstances, we are able to run the xfer optimization
+    ** only if the destination table is initially empty. Unless the
+    ** DBFLAG_Vacuum flag is set, this block generates code to make
+    ** that determination. If DBFLAG_Vacuum is set, then the destination
+    ** table is always empty.
+    **
+    ** Conditions under which the destination must be empty:
+    **
+    ** (1) There is no INTEGER PRIMARY KEY but there are indices.
+    **     (If the destination is not initially empty, the rowid fields
+    **     of index entries might need to change.)
+    **
+    ** (2) The destination has a unique index.  (The xfer optimization
+    **     is unable to test uniqueness.)
+    **
+    ** (3) onError is something other than OE_Abort and OE_Rollback.
+    */
+    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0); VdbeCoverage(v);
+    emptyDestTest = sqlite3VdbeAddOp0(v, OP_Goto);
+    sqlite3VdbeJumpHere(v, addr1);
+  }
+  if( HasRowid(pSrc) ){
+    u8 insFlags;
+    sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
+    emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
+    if( pDest->iPKey>=0 ){
+      addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
+      if( (db->mDbFlags & DBFLAG_Vacuum)==0 ){
+        sqlite3VdbeVerifyAbortable(v, onError);
+        addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
+        VdbeCoverage(v);
+        sqlite3RowidConstraint(pParse, onError, pDest);
+        sqlite3VdbeJumpHere(v, addr2);
+      }
+      autoIncStep(pParse, regAutoinc, regRowid);
+    }else if( pDest->pIndex==0 && !(db->mDbFlags & DBFLAG_VacuumInto) ){
+      addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
+    }else{
+      addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
+      assert( (pDest->tabFlags & TF_Autoincrement)==0 );
+    }
+
+    if( db->mDbFlags & DBFLAG_Vacuum ){
+      sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
+      insFlags = OPFLAG_APPEND|OPFLAG_USESEEKRESULT|OPFLAG_PREFORMAT;
+    }else{
+      insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND|OPFLAG_PREFORMAT;
+    }
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    if( (db->mDbFlags & DBFLAG_Vacuum)==0 ){
+      sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
+      insFlags &= ~OPFLAG_PREFORMAT;
+    }else
+#endif
+    {
+      sqlite3VdbeAddOp3(v, OP_RowCell, iDest, iSrc, regRowid);
+    }
+    sqlite3VdbeAddOp3(v, OP_Insert, iDest, regData, regRowid);
+    if( (db->mDbFlags & DBFLAG_Vacuum)==0 ){
+      sqlite3VdbeChangeP4(v, -1, (char*)pDest, P4_TABLE);
+    }
+    sqlite3VdbeChangeP5(v, insFlags);
+
+    sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1); VdbeCoverage(v);
+    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
+    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
+  }else{
+    sqlite3TableLock(pParse, iDbDest, pDest->tnum, 1, pDest->zName);
+    sqlite3TableLock(pParse, iDbSrc, pSrc->tnum, 0, pSrc->zName);
+  }
+  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
+    u8 idxInsFlags = 0;
+    for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
+      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
+    }
+    assert( pSrcIdx );
+    sqlite3VdbeAddOp3(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc);
+    sqlite3VdbeSetP4KeyInfo(pParse, pSrcIdx);
+    VdbeComment((v, "%s", pSrcIdx->zName));
+    sqlite3VdbeAddOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest);
+    sqlite3VdbeSetP4KeyInfo(pParse, pDestIdx);
+    sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR);
+    VdbeComment((v, "%s", pDestIdx->zName));
+    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
+    if( db->mDbFlags & DBFLAG_Vacuum ){
+      /* This INSERT command is part of a VACUUM operation, which guarantees
+      ** that the destination table is empty. If all indexed columns use
+      ** collation sequence BINARY, then it can also be assumed that the
+      ** index will be populated by inserting keys in strictly sorted
+      ** order. In this case, instead of seeking within the b-tree as part
+      ** of every OP_IdxInsert opcode, an OP_SeekEnd is added before the
+      ** OP_IdxInsert to seek to the point within the b-tree where each key
+      ** should be inserted. This is faster.
+      **
+      ** If any of the indexed columns use a collation sequence other than
+      ** BINARY, this optimization is disabled. This is because the user
+      ** might change the definition of a collation sequence and then run
+      ** a VACUUM command. In that case keys may not be written in strictly
+      ** sorted order.  */
+      for(i=0; i<pSrcIdx->nColumn; i++){
+        const char *zColl = pSrcIdx->azColl[i];
+        if( sqlite3_stricmp(sqlite3StrBINARY, zColl) ) break;
+      }
+      if( i==pSrcIdx->nColumn ){
+        idxInsFlags = OPFLAG_USESEEKRESULT|OPFLAG_PREFORMAT;
+        sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
+        sqlite3VdbeAddOp2(v, OP_RowCell, iDest, iSrc);
+      }
+    }else if( !HasRowid(pSrc) && pDestIdx->idxType==SQLITE_IDXTYPE_PRIMARYKEY ){
+      idxInsFlags |= OPFLAG_NCHANGE;
+    }
+    if( idxInsFlags!=(OPFLAG_USESEEKRESULT|OPFLAG_PREFORMAT) ){
+      sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
+      if( (db->mDbFlags & DBFLAG_Vacuum)==0
+       && !HasRowid(pDest)
+       && IsPrimaryKeyIndex(pDestIdx)
+      ){
+        codeWithoutRowidPreupdate(pParse, pDest, iDest, regData);
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_IdxInsert, iDest, regData);
+    sqlite3VdbeChangeP5(v, idxInsFlags|OPFLAG_APPEND);
+    sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr1);
+    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
+    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
+  }
+  if( emptySrcTest ) sqlite3VdbeJumpHere(v, emptySrcTest);
+  sqlite3ReleaseTempReg(pParse, regRowid);
+  sqlite3ReleaseTempReg(pParse, regData);
+  if( emptyDestTest ){
+    sqlite3AutoincrementEnd(pParse);
+    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
+    sqlite3VdbeJumpHere(v, emptyDestTest);
+    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
+    return 0;
+  }else{
+    return 1;
+  }
+}
+#endif /* SQLITE_OMIT_XFER_OPT */
+
+/************** End of insert.c **********************************************/
+/************** Begin file legacy.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Main file for the SQLite library.  The routines in this file
+** implement the programmer interface to the library.  Routines in
+** other files are for internal use by SQLite and should not be
+** accessed by users of the library.
+*/
+
+/* #include "sqliteInt.h" */
+
+/*
+** Execute SQL code.  Return one of the SQLITE_ success/failure
+** codes.  Also write an error message into memory obtained from
+** malloc() and make *pzErrMsg point to that message.
+**
+** If the SQL is a query, then for each row in the query result
+** the xCallback() function is called.  pArg becomes the first
+** argument to xCallback().  If xCallback=NULL then no callback
+** is invoked, even for queries.
+*/
+SQLITE_API int sqlite3_exec(
+  sqlite3 *db,                /* The database on which the SQL executes */
+  const char *zSql,           /* The SQL to be executed */
+  sqlite3_callback xCallback, /* Invoke this callback routine */
+  void *pArg,                 /* First argument to xCallback() */
+  char **pzErrMsg             /* Write error messages here */
+){
+  int rc = SQLITE_OK;         /* Return code */
+  const char *zLeftover;      /* Tail of unprocessed SQL */
+  sqlite3_stmt *pStmt = 0;    /* The current SQL statement */
+  char **azCols = 0;          /* Names of result columns */
+  int callbackIsInit;         /* True if callback data is initialized */
+
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+  if( zSql==0 ) zSql = "";
+
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3Error(db, SQLITE_OK);
+  while( rc==SQLITE_OK && zSql[0] ){
+    int nCol = 0;
+    char **azVals = 0;
+
+    pStmt = 0;
+    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, &zLeftover);
+    assert( rc==SQLITE_OK || pStmt==0 );
+    if( rc!=SQLITE_OK ){
+      continue;
+    }
+    if( !pStmt ){
+      /* this happens for a comment or white-space */
+      zSql = zLeftover;
+      continue;
+    }
+    callbackIsInit = 0;
+
+    while( 1 ){
+      int i;
+      rc = sqlite3_step(pStmt);
+
+      /* Invoke the callback function if required */
+      if( xCallback && (SQLITE_ROW==rc ||
+          (SQLITE_DONE==rc && !callbackIsInit
+                           && db->flags&SQLITE_NullCallback)) ){
+        if( !callbackIsInit ){
+          nCol = sqlite3_column_count(pStmt);
+          azCols = sqlite3DbMallocRaw(db, (2*nCol+1)*sizeof(const char*));
+          if( azCols==0 ){
+            goto exec_out;
+          }
+          for(i=0; i<nCol; i++){
+            azCols[i] = (char *)sqlite3_column_name(pStmt, i);
+            /* sqlite3VdbeSetColName() installs column names as UTF8
+            ** strings so there is no way for sqlite3_column_name() to fail. */
+            assert( azCols[i]!=0 );
+          }
+          callbackIsInit = 1;
+        }
+        if( rc==SQLITE_ROW ){
+          azVals = &azCols[nCol];
+          for(i=0; i<nCol; i++){
+            azVals[i] = (char *)sqlite3_column_text(pStmt, i);
+            if( !azVals[i] && sqlite3_column_type(pStmt, i)!=SQLITE_NULL ){
+              sqlite3OomFault(db);
+              goto exec_out;
+            }
+          }
+          azVals[i] = 0;
+        }
+        if( xCallback(pArg, nCol, azVals, azCols) ){
+          /* EVIDENCE-OF: R-38229-40159 If the callback function to
+          ** sqlite3_exec() returns non-zero, then sqlite3_exec() will
+          ** return SQLITE_ABORT. */
+          rc = SQLITE_ABORT;
+          sqlite3VdbeFinalize((Vdbe *)pStmt);
+          pStmt = 0;
+          sqlite3Error(db, SQLITE_ABORT);
+          goto exec_out;
+        }
+      }
+
+      if( rc!=SQLITE_ROW ){
+        rc = sqlite3VdbeFinalize((Vdbe *)pStmt);
+        pStmt = 0;
+        zSql = zLeftover;
+        while( sqlite3Isspace(zSql[0]) ) zSql++;
+        break;
+      }
+    }
+
+    sqlite3DbFree(db, azCols);
+    azCols = 0;
+  }
+
+exec_out:
+  if( pStmt ) sqlite3VdbeFinalize((Vdbe *)pStmt);
+  sqlite3DbFree(db, azCols);
+
+  rc = sqlite3ApiExit(db, rc);
+  if( rc!=SQLITE_OK && pzErrMsg ){
+    *pzErrMsg = sqlite3DbStrDup(0, sqlite3_errmsg(db));
+    if( *pzErrMsg==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      sqlite3Error(db, SQLITE_NOMEM);
+    }
+  }else if( pzErrMsg ){
+    *pzErrMsg = 0;
+  }
+
+  assert( (rc&db->errMask)==rc );
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/************** End of legacy.c **********************************************/
+/************** Begin file loadext.c *****************************************/
+/*
+** 2006 June 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to dynamically load extensions into
+** the SQLite library.
+*/
+
+#ifndef SQLITE_CORE
+  #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */
+#endif
+/************** Include sqlite3ext.h in the middle of loadext.c **************/
+/************** Begin file sqlite3ext.h **************************************/
+/*
+** 2006 June 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the SQLite interface for use by
+** shared libraries that want to be imported as extensions into
+** an SQLite instance.  Shared libraries that intend to be loaded
+** as extensions by SQLite should #include this file instead of
+** sqlite3.h.
+*/
+#ifndef SQLITE3EXT_H
+#define SQLITE3EXT_H
+/* #include "sqlite3.h" */
+
+/*
+** The following structure holds pointers to all of the SQLite API
+** routines.
+**
+** WARNING:  In order to maintain backwards compatibility, add new
+** interfaces to the end of this structure only.  If you insert new
+** interfaces in the middle of this structure, then older different
+** versions of SQLite will not be able to load each other's shared
+** libraries!
+*/
+struct sqlite3_api_routines {
+  void * (*aggregate_context)(sqlite3_context*,int nBytes);
+  int  (*aggregate_count)(sqlite3_context*);
+  int  (*bind_blob)(sqlite3_stmt*,int,const void*,int n,void(*)(void*));
+  int  (*bind_double)(sqlite3_stmt*,int,double);
+  int  (*bind_int)(sqlite3_stmt*,int,int);
+  int  (*bind_int64)(sqlite3_stmt*,int,sqlite_int64);
+  int  (*bind_null)(sqlite3_stmt*,int);
+  int  (*bind_parameter_count)(sqlite3_stmt*);
+  int  (*bind_parameter_index)(sqlite3_stmt*,const char*zName);
+  const char * (*bind_parameter_name)(sqlite3_stmt*,int);
+  int  (*bind_text)(sqlite3_stmt*,int,const char*,int n,void(*)(void*));
+  int  (*bind_text16)(sqlite3_stmt*,int,const void*,int,void(*)(void*));
+  int  (*bind_value)(sqlite3_stmt*,int,const sqlite3_value*);
+  int  (*busy_handler)(sqlite3*,int(*)(void*,int),void*);
+  int  (*busy_timeout)(sqlite3*,int ms);
+  int  (*changes)(sqlite3*);
+  int  (*close)(sqlite3*);
+  int  (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                           int eTextRep,const char*));
+  int  (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                             int eTextRep,const void*));
+  const void * (*column_blob)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes16)(sqlite3_stmt*,int iCol);
+  int  (*column_count)(sqlite3_stmt*pStmt);
+  const char * (*column_database_name)(sqlite3_stmt*,int);
+  const void * (*column_database_name16)(sqlite3_stmt*,int);
+  const char * (*column_decltype)(sqlite3_stmt*,int i);
+  const void * (*column_decltype16)(sqlite3_stmt*,int);
+  double  (*column_double)(sqlite3_stmt*,int iCol);
+  int  (*column_int)(sqlite3_stmt*,int iCol);
+  sqlite_int64  (*column_int64)(sqlite3_stmt*,int iCol);
+  const char * (*column_name)(sqlite3_stmt*,int);
+  const void * (*column_name16)(sqlite3_stmt*,int);
+  const char * (*column_origin_name)(sqlite3_stmt*,int);
+  const void * (*column_origin_name16)(sqlite3_stmt*,int);
+  const char * (*column_table_name)(sqlite3_stmt*,int);
+  const void * (*column_table_name16)(sqlite3_stmt*,int);
+  const unsigned char * (*column_text)(sqlite3_stmt*,int iCol);
+  const void * (*column_text16)(sqlite3_stmt*,int iCol);
+  int  (*column_type)(sqlite3_stmt*,int iCol);
+  sqlite3_value* (*column_value)(sqlite3_stmt*,int iCol);
+  void * (*commit_hook)(sqlite3*,int(*)(void*),void*);
+  int  (*complete)(const char*sql);
+  int  (*complete16)(const void*sql);
+  int  (*create_collation)(sqlite3*,const char*,int,void*,
+                           int(*)(void*,int,const void*,int,const void*));
+  int  (*create_collation16)(sqlite3*,const void*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*));
+  int  (*create_function)(sqlite3*,const char*,int,int,void*,
+                          void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xFinal)(sqlite3_context*));
+  int  (*create_function16)(sqlite3*,const void*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*));
+  int (*create_module)(sqlite3*,const char*,const sqlite3_module*,void*);
+  int  (*data_count)(sqlite3_stmt*pStmt);
+  sqlite3 * (*db_handle)(sqlite3_stmt*);
+  int (*declare_vtab)(sqlite3*,const char*);
+  int  (*enable_shared_cache)(int);
+  int  (*errcode)(sqlite3*db);
+  const char * (*errmsg)(sqlite3*);
+  const void * (*errmsg16)(sqlite3*);
+  int  (*exec)(sqlite3*,const char*,sqlite3_callback,void*,char**);
+  int  (*expired)(sqlite3_stmt*);
+  int  (*finalize)(sqlite3_stmt*pStmt);
+  void  (*free)(void*);
+  void  (*free_table)(char**result);
+  int  (*get_autocommit)(sqlite3*);
+  void * (*get_auxdata)(sqlite3_context*,int);
+  int  (*get_table)(sqlite3*,const char*,char***,int*,int*,char**);
+  int  (*global_recover)(void);
+  void  (*interruptx)(sqlite3*);
+  sqlite_int64  (*last_insert_rowid)(sqlite3*);
+  const char * (*libversion)(void);
+  int  (*libversion_number)(void);
+  void *(*malloc)(int);
+  char * (*mprintf)(const char*,...);
+  int  (*open)(const char*,sqlite3**);
+  int  (*open16)(const void*,sqlite3**);
+  int  (*prepare)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int  (*prepare16)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  void * (*profile)(sqlite3*,void(*)(void*,const char*,sqlite_uint64),void*);
+  void  (*progress_handler)(sqlite3*,int,int(*)(void*),void*);
+  void *(*realloc)(void*,int);
+  int  (*reset)(sqlite3_stmt*pStmt);
+  void  (*result_blob)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_double)(sqlite3_context*,double);
+  void  (*result_error)(sqlite3_context*,const char*,int);
+  void  (*result_error16)(sqlite3_context*,const void*,int);
+  void  (*result_int)(sqlite3_context*,int);
+  void  (*result_int64)(sqlite3_context*,sqlite_int64);
+  void  (*result_null)(sqlite3_context*);
+  void  (*result_text)(sqlite3_context*,const char*,int,void(*)(void*));
+  void  (*result_text16)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16be)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16le)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_value)(sqlite3_context*,sqlite3_value*);
+  void * (*rollback_hook)(sqlite3*,void(*)(void*),void*);
+  int  (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,
+                         const char*,const char*),void*);
+  void  (*set_auxdata)(sqlite3_context*,int,void*,void (*)(void*));
+  char * (*xsnprintf)(int,char*,const char*,...);
+  int  (*step)(sqlite3_stmt*);
+  int  (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,
+                                char const**,char const**,int*,int*,int*);
+  void  (*thread_cleanup)(void);
+  int  (*total_changes)(sqlite3*);
+  void * (*trace)(sqlite3*,void(*xTrace)(void*,const char*),void*);
+  int  (*transfer_bindings)(sqlite3_stmt*,sqlite3_stmt*);
+  void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,
+                                         sqlite_int64),void*);
+  void * (*user_data)(sqlite3_context*);
+  const void * (*value_blob)(sqlite3_value*);
+  int  (*value_bytes)(sqlite3_value*);
+  int  (*value_bytes16)(sqlite3_value*);
+  double  (*value_double)(sqlite3_value*);
+  int  (*value_int)(sqlite3_value*);
+  sqlite_int64  (*value_int64)(sqlite3_value*);
+  int  (*value_numeric_type)(sqlite3_value*);
+  const unsigned char * (*value_text)(sqlite3_value*);
+  const void * (*value_text16)(sqlite3_value*);
+  const void * (*value_text16be)(sqlite3_value*);
+  const void * (*value_text16le)(sqlite3_value*);
+  int  (*value_type)(sqlite3_value*);
+  char *(*vmprintf)(const char*,va_list);
+  /* Added ??? */
+  int (*overload_function)(sqlite3*, const char *zFuncName, int nArg);
+  /* Added by 3.3.13 */
+  int (*prepare_v2)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int (*prepare16_v2)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  int (*clear_bindings)(sqlite3_stmt*);
+  /* Added by 3.4.1 */
+  int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,
+                          void (*xDestroy)(void *));
+  /* Added by 3.5.0 */
+  int (*bind_zeroblob)(sqlite3_stmt*,int,int);
+  int (*blob_bytes)(sqlite3_blob*);
+  int (*blob_close)(sqlite3_blob*);
+  int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,
+                   int,sqlite3_blob**);
+  int (*blob_read)(sqlite3_blob*,void*,int,int);
+  int (*blob_write)(sqlite3_blob*,const void*,int,int);
+  int (*create_collation_v2)(sqlite3*,const char*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*),
+                             void(*)(void*));
+  int (*file_control)(sqlite3*,const char*,int,void*);
+  sqlite3_int64 (*memory_highwater)(int);
+  sqlite3_int64 (*memory_used)(void);
+  sqlite3_mutex *(*mutex_alloc)(int);
+  void (*mutex_enter)(sqlite3_mutex*);
+  void (*mutex_free)(sqlite3_mutex*);
+  void (*mutex_leave)(sqlite3_mutex*);
+  int (*mutex_try)(sqlite3_mutex*);
+  int (*open_v2)(const char*,sqlite3**,int,const char*);
+  int (*release_memory)(int);
+  void (*result_error_nomem)(sqlite3_context*);
+  void (*result_error_toobig)(sqlite3_context*);
+  int (*sleep)(int);
+  void (*soft_heap_limit)(int);
+  sqlite3_vfs *(*vfs_find)(const char*);
+  int (*vfs_register)(sqlite3_vfs*,int);
+  int (*vfs_unregister)(sqlite3_vfs*);
+  int (*xthreadsafe)(void);
+  void (*result_zeroblob)(sqlite3_context*,int);
+  void (*result_error_code)(sqlite3_context*,int);
+  int (*test_control)(int, ...);
+  void (*randomness)(int,void*);
+  sqlite3 *(*context_db_handle)(sqlite3_context*);
+  int (*extended_result_codes)(sqlite3*,int);
+  int (*limit)(sqlite3*,int,int);
+  sqlite3_stmt *(*next_stmt)(sqlite3*,sqlite3_stmt*);
+  const char *(*sql)(sqlite3_stmt*);
+  int (*status)(int,int*,int*,int);
+  int (*backup_finish)(sqlite3_backup*);
+  sqlite3_backup *(*backup_init)(sqlite3*,const char*,sqlite3*,const char*);
+  int (*backup_pagecount)(sqlite3_backup*);
+  int (*backup_remaining)(sqlite3_backup*);
+  int (*backup_step)(sqlite3_backup*,int);
+  const char *(*compileoption_get)(int);
+  int (*compileoption_used)(const char*);
+  int (*create_function_v2)(sqlite3*,const char*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void(*xDestroy)(void*));
+  int (*db_config)(sqlite3*,int,...);
+  sqlite3_mutex *(*db_mutex)(sqlite3*);
+  int (*db_status)(sqlite3*,int,int*,int*,int);
+  int (*extended_errcode)(sqlite3*);
+  void (*log)(int,const char*,...);
+  sqlite3_int64 (*soft_heap_limit64)(sqlite3_int64);
+  const char *(*sourceid)(void);
+  int (*stmt_status)(sqlite3_stmt*,int,int);
+  int (*strnicmp)(const char*,const char*,int);
+  int (*unlock_notify)(sqlite3*,void(*)(void**,int),void*);
+  int (*wal_autocheckpoint)(sqlite3*,int);
+  int (*wal_checkpoint)(sqlite3*,const char*);
+  void *(*wal_hook)(sqlite3*,int(*)(void*,sqlite3*,const char*,int),void*);
+  int (*blob_reopen)(sqlite3_blob*,sqlite3_int64);
+  int (*vtab_config)(sqlite3*,int op,...);
+  int (*vtab_on_conflict)(sqlite3*);
+  /* Version 3.7.16 and later */
+  int (*close_v2)(sqlite3*);
+  const char *(*db_filename)(sqlite3*,const char*);
+  int (*db_readonly)(sqlite3*,const char*);
+  int (*db_release_memory)(sqlite3*);
+  const char *(*errstr)(int);
+  int (*stmt_busy)(sqlite3_stmt*);
+  int (*stmt_readonly)(sqlite3_stmt*);
+  int (*stricmp)(const char*,const char*);
+  int (*uri_boolean)(const char*,const char*,int);
+  sqlite3_int64 (*uri_int64)(const char*,const char*,sqlite3_int64);
+  const char *(*uri_parameter)(const char*,const char*);
+  char *(*xvsnprintf)(int,char*,const char*,va_list);
+  int (*wal_checkpoint_v2)(sqlite3*,const char*,int,int*,int*);
+  /* Version 3.8.7 and later */
+  int (*auto_extension)(void(*)(void));
+  int (*bind_blob64)(sqlite3_stmt*,int,const void*,sqlite3_uint64,
+                     void(*)(void*));
+  int (*bind_text64)(sqlite3_stmt*,int,const char*,sqlite3_uint64,
+                      void(*)(void*),unsigned char);
+  int (*cancel_auto_extension)(void(*)(void));
+  int (*load_extension)(sqlite3*,const char*,const char*,char**);
+  void *(*malloc64)(sqlite3_uint64);
+  sqlite3_uint64 (*msize)(void*);
+  void *(*realloc64)(void*,sqlite3_uint64);
+  void (*reset_auto_extension)(void);
+  void (*result_blob64)(sqlite3_context*,const void*,sqlite3_uint64,
+                        void(*)(void*));
+  void (*result_text64)(sqlite3_context*,const char*,sqlite3_uint64,
+                         void(*)(void*), unsigned char);
+  int (*strglob)(const char*,const char*);
+  /* Version 3.8.11 and later */
+  sqlite3_value *(*value_dup)(const sqlite3_value*);
+  void (*value_free)(sqlite3_value*);
+  int (*result_zeroblob64)(sqlite3_context*,sqlite3_uint64);
+  int (*bind_zeroblob64)(sqlite3_stmt*, int, sqlite3_uint64);
+  /* Version 3.9.0 and later */
+  unsigned int (*value_subtype)(sqlite3_value*);
+  void (*result_subtype)(sqlite3_context*,unsigned int);
+  /* Version 3.10.0 and later */
+  int (*status64)(int,sqlite3_int64*,sqlite3_int64*,int);
+  int (*strlike)(const char*,const char*,unsigned int);
+  int (*db_cacheflush)(sqlite3*);
+  /* Version 3.12.0 and later */
+  int (*system_errno)(sqlite3*);
+  /* Version 3.14.0 and later */
+  int (*trace_v2)(sqlite3*,unsigned,int(*)(unsigned,void*,void*,void*),void*);
+  char *(*expanded_sql)(sqlite3_stmt*);
+  /* Version 3.18.0 and later */
+  void (*set_last_insert_rowid)(sqlite3*,sqlite3_int64);
+  /* Version 3.20.0 and later */
+  int (*prepare_v3)(sqlite3*,const char*,int,unsigned int,
+                    sqlite3_stmt**,const char**);
+  int (*prepare16_v3)(sqlite3*,const void*,int,unsigned int,
+                      sqlite3_stmt**,const void**);
+  int (*bind_pointer)(sqlite3_stmt*,int,void*,const char*,void(*)(void*));
+  void (*result_pointer)(sqlite3_context*,void*,const char*,void(*)(void*));
+  void *(*value_pointer)(sqlite3_value*,const char*);
+  int (*vtab_nochange)(sqlite3_context*);
+  int (*value_nochange)(sqlite3_value*);
+  const char *(*vtab_collation)(sqlite3_index_info*,int);
+  /* Version 3.24.0 and later */
+  int (*keyword_count)(void);
+  int (*keyword_name)(int,const char**,int*);
+  int (*keyword_check)(const char*,int);
+  sqlite3_str *(*str_new)(sqlite3*);
+  char *(*str_finish)(sqlite3_str*);
+  void (*str_appendf)(sqlite3_str*, const char *zFormat, ...);
+  void (*str_vappendf)(sqlite3_str*, const char *zFormat, va_list);
+  void (*str_append)(sqlite3_str*, const char *zIn, int N);
+  void (*str_appendall)(sqlite3_str*, const char *zIn);
+  void (*str_appendchar)(sqlite3_str*, int N, char C);
+  void (*str_reset)(sqlite3_str*);
+  int (*str_errcode)(sqlite3_str*);
+  int (*str_length)(sqlite3_str*);
+  char *(*str_value)(sqlite3_str*);
+  /* Version 3.25.0 and later */
+  int (*create_window_function)(sqlite3*,const char*,int,int,void*,
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void (*xValue)(sqlite3_context*),
+                            void (*xInv)(sqlite3_context*,int,sqlite3_value**),
+                            void(*xDestroy)(void*));
+  /* Version 3.26.0 and later */
+  const char *(*normalized_sql)(sqlite3_stmt*);
+  /* Version 3.28.0 and later */
+  int (*stmt_isexplain)(sqlite3_stmt*);
+  int (*value_frombind)(sqlite3_value*);
+  /* Version 3.30.0 and later */
+  int (*drop_modules)(sqlite3*,const char**);
+  /* Version 3.31.0 and later */
+  sqlite3_int64 (*hard_heap_limit64)(sqlite3_int64);
+  const char *(*uri_key)(const char*,int);
+  const char *(*filename_database)(const char*);
+  const char *(*filename_journal)(const char*);
+  const char *(*filename_wal)(const char*);
+  /* Version 3.32.0 and later */
+  const char *(*create_filename)(const char*,const char*,const char*,
+                           int,const char**);
+  void (*free_filename)(const char*);
+  sqlite3_file *(*database_file_object)(const char*);
+  /* Version 3.34.0 and later */
+  int (*txn_state)(sqlite3*,const char*);
+  /* Version 3.36.1 and later */
+  sqlite3_int64 (*changes64)(sqlite3*);
+  sqlite3_int64 (*total_changes64)(sqlite3*);
+  /* Version 3.37.0 and later */
+  int (*autovacuum_pages)(sqlite3*,
+     unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
+     void*, void(*)(void*));
+  /* Version 3.38.0 and later */
+  int (*error_offset)(sqlite3*);
+  int (*vtab_rhs_value)(sqlite3_index_info*,int,sqlite3_value**);
+  int (*vtab_distinct)(sqlite3_index_info*);
+  int (*vtab_in)(sqlite3_index_info*,int,int);
+  int (*vtab_in_first)(sqlite3_value*,sqlite3_value**);
+  int (*vtab_in_next)(sqlite3_value*,sqlite3_value**);
+  /* Version 3.39.0 and later */
+  int (*deserialize)(sqlite3*,const char*,unsigned char*,
+                     sqlite3_int64,sqlite3_int64,unsigned);
+  unsigned char *(*serialize)(sqlite3*,const char *,sqlite3_int64*,
+                              unsigned int);
+  const char *(*db_name)(sqlite3*,int);
+  /* Version 3.40.0 and later */
+  int (*value_encoding)(sqlite3_value*);
+  /* Version 3.41.0 and later */
+  int (*is_interrupted)(sqlite3*);
+  /* Version 3.43.0 and later */
+  int (*stmt_explain)(sqlite3_stmt*,int);
+  /* Version 3.44.0 and later */
+  void *(*get_clientdata)(sqlite3*,const char*);
+  int (*set_clientdata)(sqlite3*, const char*, void*, void(*)(void*));
+};
+
+/*
+** This is the function signature used for all extension entry points.  It
+** is also defined in the file "loadext.c".
+*/
+typedef int (*sqlite3_loadext_entry)(
+  sqlite3 *db,                       /* Handle to the database. */
+  char **pzErrMsg,                   /* Used to set error string on failure. */
+  const sqlite3_api_routines *pThunk /* Extension API function pointers. */
+);
+
+/*
+** The following macros redefine the API routines so that they are
+** redirected through the global sqlite3_api structure.
+**
+** This header file is also used by the loadext.c source file
+** (part of the main SQLite library - not an extension) so that
+** it can get access to the sqlite3_api_routines structure
+** definition.  But the main library does not want to redefine
+** the API.  So the redefinition macros are only valid if the
+** SQLITE_CORE macros is undefined.
+*/
+#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+#define sqlite3_aggregate_context      sqlite3_api->aggregate_context
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_aggregate_count        sqlite3_api->aggregate_count
+#endif
+#define sqlite3_bind_blob              sqlite3_api->bind_blob
+#define sqlite3_bind_double            sqlite3_api->bind_double
+#define sqlite3_bind_int               sqlite3_api->bind_int
+#define sqlite3_bind_int64             sqlite3_api->bind_int64
+#define sqlite3_bind_null              sqlite3_api->bind_null
+#define sqlite3_bind_parameter_count   sqlite3_api->bind_parameter_count
+#define sqlite3_bind_parameter_index   sqlite3_api->bind_parameter_index
+#define sqlite3_bind_parameter_name    sqlite3_api->bind_parameter_name
+#define sqlite3_bind_text              sqlite3_api->bind_text
+#define sqlite3_bind_text16            sqlite3_api->bind_text16
+#define sqlite3_bind_value             sqlite3_api->bind_value
+#define sqlite3_busy_handler           sqlite3_api->busy_handler
+#define sqlite3_busy_timeout           sqlite3_api->busy_timeout
+#define sqlite3_changes                sqlite3_api->changes
+#define sqlite3_close                  sqlite3_api->close
+#define sqlite3_collation_needed       sqlite3_api->collation_needed
+#define sqlite3_collation_needed16     sqlite3_api->collation_needed16
+#define sqlite3_column_blob            sqlite3_api->column_blob
+#define sqlite3_column_bytes           sqlite3_api->column_bytes
+#define sqlite3_column_bytes16         sqlite3_api->column_bytes16
+#define sqlite3_column_count           sqlite3_api->column_count
+#define sqlite3_column_database_name   sqlite3_api->column_database_name
+#define sqlite3_column_database_name16 sqlite3_api->column_database_name16
+#define sqlite3_column_decltype        sqlite3_api->column_decltype
+#define sqlite3_column_decltype16      sqlite3_api->column_decltype16
+#define sqlite3_column_double          sqlite3_api->column_double
+#define sqlite3_column_int             sqlite3_api->column_int
+#define sqlite3_column_int64           sqlite3_api->column_int64
+#define sqlite3_column_name            sqlite3_api->column_name
+#define sqlite3_column_name16          sqlite3_api->column_name16
+#define sqlite3_column_origin_name     sqlite3_api->column_origin_name
+#define sqlite3_column_origin_name16   sqlite3_api->column_origin_name16
+#define sqlite3_column_table_name      sqlite3_api->column_table_name
+#define sqlite3_column_table_name16    sqlite3_api->column_table_name16
+#define sqlite3_column_text            sqlite3_api->column_text
+#define sqlite3_column_text16          sqlite3_api->column_text16
+#define sqlite3_column_type            sqlite3_api->column_type
+#define sqlite3_column_value           sqlite3_api->column_value
+#define sqlite3_commit_hook            sqlite3_api->commit_hook
+#define sqlite3_complete               sqlite3_api->complete
+#define sqlite3_complete16             sqlite3_api->complete16
+#define sqlite3_create_collation       sqlite3_api->create_collation
+#define sqlite3_create_collation16     sqlite3_api->create_collation16
+#define sqlite3_create_function        sqlite3_api->create_function
+#define sqlite3_create_function16      sqlite3_api->create_function16
+#define sqlite3_create_module          sqlite3_api->create_module
+#define sqlite3_create_module_v2       sqlite3_api->create_module_v2
+#define sqlite3_data_count             sqlite3_api->data_count
+#define sqlite3_db_handle              sqlite3_api->db_handle
+#define sqlite3_declare_vtab           sqlite3_api->declare_vtab
+#define sqlite3_enable_shared_cache    sqlite3_api->enable_shared_cache
+#define sqlite3_errcode                sqlite3_api->errcode
+#define sqlite3_errmsg                 sqlite3_api->errmsg
+#define sqlite3_errmsg16               sqlite3_api->errmsg16
+#define sqlite3_exec                   sqlite3_api->exec
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_expired                sqlite3_api->expired
+#endif
+#define sqlite3_finalize               sqlite3_api->finalize
+#define sqlite3_free                   sqlite3_api->free
+#define sqlite3_free_table             sqlite3_api->free_table
+#define sqlite3_get_autocommit         sqlite3_api->get_autocommit
+#define sqlite3_get_auxdata            sqlite3_api->get_auxdata
+#define sqlite3_get_table              sqlite3_api->get_table
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_global_recover         sqlite3_api->global_recover
+#endif
+#define sqlite3_interrupt              sqlite3_api->interruptx
+#define sqlite3_last_insert_rowid      sqlite3_api->last_insert_rowid
+#define sqlite3_libversion             sqlite3_api->libversion
+#define sqlite3_libversion_number      sqlite3_api->libversion_number
+#define sqlite3_malloc                 sqlite3_api->malloc
+#define sqlite3_mprintf                sqlite3_api->mprintf
+#define sqlite3_open                   sqlite3_api->open
+#define sqlite3_open16                 sqlite3_api->open16
+#define sqlite3_prepare                sqlite3_api->prepare
+#define sqlite3_prepare16              sqlite3_api->prepare16
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_profile                sqlite3_api->profile
+#define sqlite3_progress_handler       sqlite3_api->progress_handler
+#define sqlite3_realloc                sqlite3_api->realloc
+#define sqlite3_reset                  sqlite3_api->reset
+#define sqlite3_result_blob            sqlite3_api->result_blob
+#define sqlite3_result_double          sqlite3_api->result_double
+#define sqlite3_result_error           sqlite3_api->result_error
+#define sqlite3_result_error16         sqlite3_api->result_error16
+#define sqlite3_result_int             sqlite3_api->result_int
+#define sqlite3_result_int64           sqlite3_api->result_int64
+#define sqlite3_result_null            sqlite3_api->result_null
+#define sqlite3_result_text            sqlite3_api->result_text
+#define sqlite3_result_text16          sqlite3_api->result_text16
+#define sqlite3_result_text16be        sqlite3_api->result_text16be
+#define sqlite3_result_text16le        sqlite3_api->result_text16le
+#define sqlite3_result_value           sqlite3_api->result_value
+#define sqlite3_rollback_hook          sqlite3_api->rollback_hook
+#define sqlite3_set_authorizer         sqlite3_api->set_authorizer
+#define sqlite3_set_auxdata            sqlite3_api->set_auxdata
+#define sqlite3_snprintf               sqlite3_api->xsnprintf
+#define sqlite3_step                   sqlite3_api->step
+#define sqlite3_table_column_metadata  sqlite3_api->table_column_metadata
+#define sqlite3_thread_cleanup         sqlite3_api->thread_cleanup
+#define sqlite3_total_changes          sqlite3_api->total_changes
+#define sqlite3_trace                  sqlite3_api->trace
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_transfer_bindings      sqlite3_api->transfer_bindings
+#endif
+#define sqlite3_update_hook            sqlite3_api->update_hook
+#define sqlite3_user_data              sqlite3_api->user_data
+#define sqlite3_value_blob             sqlite3_api->value_blob
+#define sqlite3_value_bytes            sqlite3_api->value_bytes
+#define sqlite3_value_bytes16          sqlite3_api->value_bytes16
+#define sqlite3_value_double           sqlite3_api->value_double
+#define sqlite3_value_int              sqlite3_api->value_int
+#define sqlite3_value_int64            sqlite3_api->value_int64
+#define sqlite3_value_numeric_type     sqlite3_api->value_numeric_type
+#define sqlite3_value_text             sqlite3_api->value_text
+#define sqlite3_value_text16           sqlite3_api->value_text16
+#define sqlite3_value_text16be         sqlite3_api->value_text16be
+#define sqlite3_value_text16le         sqlite3_api->value_text16le
+#define sqlite3_value_type             sqlite3_api->value_type
+#define sqlite3_vmprintf               sqlite3_api->vmprintf
+#define sqlite3_vsnprintf              sqlite3_api->xvsnprintf
+#define sqlite3_overload_function      sqlite3_api->overload_function
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_clear_bindings         sqlite3_api->clear_bindings
+#define sqlite3_bind_zeroblob          sqlite3_api->bind_zeroblob
+#define sqlite3_blob_bytes             sqlite3_api->blob_bytes
+#define sqlite3_blob_close             sqlite3_api->blob_close
+#define sqlite3_blob_open              sqlite3_api->blob_open
+#define sqlite3_blob_read              sqlite3_api->blob_read
+#define sqlite3_blob_write             sqlite3_api->blob_write
+#define sqlite3_create_collation_v2    sqlite3_api->create_collation_v2
+#define sqlite3_file_control           sqlite3_api->file_control
+#define sqlite3_memory_highwater       sqlite3_api->memory_highwater
+#define sqlite3_memory_used            sqlite3_api->memory_used
+#define sqlite3_mutex_alloc            sqlite3_api->mutex_alloc
+#define sqlite3_mutex_enter            sqlite3_api->mutex_enter
+#define sqlite3_mutex_free             sqlite3_api->mutex_free
+#define sqlite3_mutex_leave            sqlite3_api->mutex_leave
+#define sqlite3_mutex_try              sqlite3_api->mutex_try
+#define sqlite3_open_v2                sqlite3_api->open_v2
+#define sqlite3_release_memory         sqlite3_api->release_memory
+#define sqlite3_result_error_nomem     sqlite3_api->result_error_nomem
+#define sqlite3_result_error_toobig    sqlite3_api->result_error_toobig
+#define sqlite3_sleep                  sqlite3_api->sleep
+#define sqlite3_soft_heap_limit        sqlite3_api->soft_heap_limit
+#define sqlite3_vfs_find               sqlite3_api->vfs_find
+#define sqlite3_vfs_register           sqlite3_api->vfs_register
+#define sqlite3_vfs_unregister         sqlite3_api->vfs_unregister
+#define sqlite3_threadsafe             sqlite3_api->xthreadsafe
+#define sqlite3_result_zeroblob        sqlite3_api->result_zeroblob
+#define sqlite3_result_error_code      sqlite3_api->result_error_code
+#define sqlite3_test_control           sqlite3_api->test_control
+#define sqlite3_randomness             sqlite3_api->randomness
+#define sqlite3_context_db_handle      sqlite3_api->context_db_handle
+#define sqlite3_extended_result_codes  sqlite3_api->extended_result_codes
+#define sqlite3_limit                  sqlite3_api->limit
+#define sqlite3_next_stmt              sqlite3_api->next_stmt
+#define sqlite3_sql                    sqlite3_api->sql
+#define sqlite3_status                 sqlite3_api->status
+#define sqlite3_backup_finish          sqlite3_api->backup_finish
+#define sqlite3_backup_init            sqlite3_api->backup_init
+#define sqlite3_backup_pagecount       sqlite3_api->backup_pagecount
+#define sqlite3_backup_remaining       sqlite3_api->backup_remaining
+#define sqlite3_backup_step            sqlite3_api->backup_step
+#define sqlite3_compileoption_get      sqlite3_api->compileoption_get
+#define sqlite3_compileoption_used     sqlite3_api->compileoption_used
+#define sqlite3_create_function_v2     sqlite3_api->create_function_v2
+#define sqlite3_db_config              sqlite3_api->db_config
+#define sqlite3_db_mutex               sqlite3_api->db_mutex
+#define sqlite3_db_status              sqlite3_api->db_status
+#define sqlite3_extended_errcode       sqlite3_api->extended_errcode
+#define sqlite3_log                    sqlite3_api->log
+#define sqlite3_soft_heap_limit64      sqlite3_api->soft_heap_limit64
+#define sqlite3_sourceid               sqlite3_api->sourceid
+#define sqlite3_stmt_status            sqlite3_api->stmt_status
+#define sqlite3_strnicmp               sqlite3_api->strnicmp
+#define sqlite3_unlock_notify          sqlite3_api->unlock_notify
+#define sqlite3_wal_autocheckpoint     sqlite3_api->wal_autocheckpoint
+#define sqlite3_wal_checkpoint         sqlite3_api->wal_checkpoint
+#define sqlite3_wal_hook               sqlite3_api->wal_hook
+#define sqlite3_blob_reopen            sqlite3_api->blob_reopen
+#define sqlite3_vtab_config            sqlite3_api->vtab_config
+#define sqlite3_vtab_on_conflict       sqlite3_api->vtab_on_conflict
+/* Version 3.7.16 and later */
+#define sqlite3_close_v2               sqlite3_api->close_v2
+#define sqlite3_db_filename            sqlite3_api->db_filename
+#define sqlite3_db_readonly            sqlite3_api->db_readonly
+#define sqlite3_db_release_memory      sqlite3_api->db_release_memory
+#define sqlite3_errstr                 sqlite3_api->errstr
+#define sqlite3_stmt_busy              sqlite3_api->stmt_busy
+#define sqlite3_stmt_readonly          sqlite3_api->stmt_readonly
+#define sqlite3_stricmp                sqlite3_api->stricmp
+#define sqlite3_uri_boolean            sqlite3_api->uri_boolean
+#define sqlite3_uri_int64              sqlite3_api->uri_int64
+#define sqlite3_uri_parameter          sqlite3_api->uri_parameter
+#define sqlite3_uri_vsnprintf          sqlite3_api->xvsnprintf
+#define sqlite3_wal_checkpoint_v2      sqlite3_api->wal_checkpoint_v2
+/* Version 3.8.7 and later */
+#define sqlite3_auto_extension         sqlite3_api->auto_extension
+#define sqlite3_bind_blob64            sqlite3_api->bind_blob64
+#define sqlite3_bind_text64            sqlite3_api->bind_text64
+#define sqlite3_cancel_auto_extension  sqlite3_api->cancel_auto_extension
+#define sqlite3_load_extension         sqlite3_api->load_extension
+#define sqlite3_malloc64               sqlite3_api->malloc64
+#define sqlite3_msize                  sqlite3_api->msize
+#define sqlite3_realloc64              sqlite3_api->realloc64
+#define sqlite3_reset_auto_extension   sqlite3_api->reset_auto_extension
+#define sqlite3_result_blob64          sqlite3_api->result_blob64
+#define sqlite3_result_text64          sqlite3_api->result_text64
+#define sqlite3_strglob                sqlite3_api->strglob
+/* Version 3.8.11 and later */
+#define sqlite3_value_dup              sqlite3_api->value_dup
+#define sqlite3_value_free             sqlite3_api->value_free
+#define sqlite3_result_zeroblob64      sqlite3_api->result_zeroblob64
+#define sqlite3_bind_zeroblob64        sqlite3_api->bind_zeroblob64
+/* Version 3.9.0 and later */
+#define sqlite3_value_subtype          sqlite3_api->value_subtype
+#define sqlite3_result_subtype         sqlite3_api->result_subtype
+/* Version 3.10.0 and later */
+#define sqlite3_status64               sqlite3_api->status64
+#define sqlite3_strlike                sqlite3_api->strlike
+#define sqlite3_db_cacheflush          sqlite3_api->db_cacheflush
+/* Version 3.12.0 and later */
+#define sqlite3_system_errno           sqlite3_api->system_errno
+/* Version 3.14.0 and later */
+#define sqlite3_trace_v2               sqlite3_api->trace_v2
+#define sqlite3_expanded_sql           sqlite3_api->expanded_sql
+/* Version 3.18.0 and later */
+#define sqlite3_set_last_insert_rowid  sqlite3_api->set_last_insert_rowid
+/* Version 3.20.0 and later */
+#define sqlite3_prepare_v3             sqlite3_api->prepare_v3
+#define sqlite3_prepare16_v3           sqlite3_api->prepare16_v3
+#define sqlite3_bind_pointer           sqlite3_api->bind_pointer
+#define sqlite3_result_pointer         sqlite3_api->result_pointer
+#define sqlite3_value_pointer          sqlite3_api->value_pointer
+/* Version 3.22.0 and later */
+#define sqlite3_vtab_nochange          sqlite3_api->vtab_nochange
+#define sqlite3_value_nochange         sqlite3_api->value_nochange
+#define sqlite3_vtab_collation         sqlite3_api->vtab_collation
+/* Version 3.24.0 and later */
+#define sqlite3_keyword_count          sqlite3_api->keyword_count
+#define sqlite3_keyword_name           sqlite3_api->keyword_name
+#define sqlite3_keyword_check          sqlite3_api->keyword_check
+#define sqlite3_str_new                sqlite3_api->str_new
+#define sqlite3_str_finish             sqlite3_api->str_finish
+#define sqlite3_str_appendf            sqlite3_api->str_appendf
+#define sqlite3_str_vappendf           sqlite3_api->str_vappendf
+#define sqlite3_str_append             sqlite3_api->str_append
+#define sqlite3_str_appendall          sqlite3_api->str_appendall
+#define sqlite3_str_appendchar         sqlite3_api->str_appendchar
+#define sqlite3_str_reset              sqlite3_api->str_reset
+#define sqlite3_str_errcode            sqlite3_api->str_errcode
+#define sqlite3_str_length             sqlite3_api->str_length
+#define sqlite3_str_value              sqlite3_api->str_value
+/* Version 3.25.0 and later */
+#define sqlite3_create_window_function sqlite3_api->create_window_function
+/* Version 3.26.0 and later */
+#define sqlite3_normalized_sql         sqlite3_api->normalized_sql
+/* Version 3.28.0 and later */
+#define sqlite3_stmt_isexplain         sqlite3_api->stmt_isexplain
+#define sqlite3_value_frombind         sqlite3_api->value_frombind
+/* Version 3.30.0 and later */
+#define sqlite3_drop_modules           sqlite3_api->drop_modules
+/* Version 3.31.0 and later */
+#define sqlite3_hard_heap_limit64      sqlite3_api->hard_heap_limit64
+#define sqlite3_uri_key                sqlite3_api->uri_key
+#define sqlite3_filename_database      sqlite3_api->filename_database
+#define sqlite3_filename_journal       sqlite3_api->filename_journal
+#define sqlite3_filename_wal           sqlite3_api->filename_wal
+/* Version 3.32.0 and later */
+#define sqlite3_create_filename        sqlite3_api->create_filename
+#define sqlite3_free_filename          sqlite3_api->free_filename
+#define sqlite3_database_file_object   sqlite3_api->database_file_object
+/* Version 3.34.0 and later */
+#define sqlite3_txn_state              sqlite3_api->txn_state
+/* Version 3.36.1 and later */
+#define sqlite3_changes64              sqlite3_api->changes64
+#define sqlite3_total_changes64        sqlite3_api->total_changes64
+/* Version 3.37.0 and later */
+#define sqlite3_autovacuum_pages       sqlite3_api->autovacuum_pages
+/* Version 3.38.0 and later */
+#define sqlite3_error_offset           sqlite3_api->error_offset
+#define sqlite3_vtab_rhs_value         sqlite3_api->vtab_rhs_value
+#define sqlite3_vtab_distinct          sqlite3_api->vtab_distinct
+#define sqlite3_vtab_in                sqlite3_api->vtab_in
+#define sqlite3_vtab_in_first          sqlite3_api->vtab_in_first
+#define sqlite3_vtab_in_next           sqlite3_api->vtab_in_next
+/* Version 3.39.0 and later */
+#ifndef SQLITE_OMIT_DESERIALIZE
+#define sqlite3_deserialize            sqlite3_api->deserialize
+#define sqlite3_serialize              sqlite3_api->serialize
+#endif
+#define sqlite3_db_name                sqlite3_api->db_name
+/* Version 3.40.0 and later */
+#define sqlite3_value_encoding         sqlite3_api->value_encoding
+/* Version 3.41.0 and later */
+#define sqlite3_is_interrupted         sqlite3_api->is_interrupted
+/* Version 3.43.0 and later */
+#define sqlite3_stmt_explain           sqlite3_api->stmt_explain
+/* Version 3.44.0 and later */
+#define sqlite3_get_clientdata         sqlite3_api->get_clientdata
+#define sqlite3_set_clientdata         sqlite3_api->set_clientdata
+#endif /* !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION) */
+
+#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  /* This case when the file really is being compiled as a loadable
+  ** extension */
+# define SQLITE_EXTENSION_INIT1     const sqlite3_api_routines *sqlite3_api=0;
+# define SQLITE_EXTENSION_INIT2(v)  sqlite3_api=v;
+# define SQLITE_EXTENSION_INIT3     \
+    extern const sqlite3_api_routines *sqlite3_api;
+#else
+  /* This case when the file is being statically linked into the
+  ** application */
+# define SQLITE_EXTENSION_INIT1     /*no-op*/
+# define SQLITE_EXTENSION_INIT2(v)  (void)v; /* unused parameter */
+# define SQLITE_EXTENSION_INIT3     /*no-op*/
+#endif
+
+#endif /* SQLITE3EXT_H */
+
+/************** End of sqlite3ext.h ******************************************/
+/************** Continuing where we left off in loadext.c ********************/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Some API routines are omitted when various features are
+** excluded from a build of SQLite.  Substitute a NULL pointer
+** for any missing APIs.
+*/
+#ifndef SQLITE_ENABLE_COLUMN_METADATA
+# define sqlite3_column_database_name   0
+# define sqlite3_column_database_name16 0
+# define sqlite3_column_table_name      0
+# define sqlite3_column_table_name16    0
+# define sqlite3_column_origin_name     0
+# define sqlite3_column_origin_name16   0
+#endif
+
+#ifdef SQLITE_OMIT_AUTHORIZATION
+# define sqlite3_set_authorizer         0
+#endif
+
+#ifdef SQLITE_OMIT_UTF16
+# define sqlite3_bind_text16            0
+# define sqlite3_collation_needed16     0
+# define sqlite3_column_decltype16      0
+# define sqlite3_column_name16          0
+# define sqlite3_column_text16          0
+# define sqlite3_complete16             0
+# define sqlite3_create_collation16     0
+# define sqlite3_create_function16      0
+# define sqlite3_errmsg16               0
+# define sqlite3_open16                 0
+# define sqlite3_prepare16              0
+# define sqlite3_prepare16_v2           0
+# define sqlite3_prepare16_v3           0
+# define sqlite3_result_error16         0
+# define sqlite3_result_text16          0
+# define sqlite3_result_text16be        0
+# define sqlite3_result_text16le        0
+# define sqlite3_value_text16           0
+# define sqlite3_value_text16be         0
+# define sqlite3_value_text16le         0
+# define sqlite3_column_database_name16 0
+# define sqlite3_column_table_name16    0
+# define sqlite3_column_origin_name16   0
+#endif
+
+#ifdef SQLITE_OMIT_COMPLETE
+# define sqlite3_complete 0
+# define sqlite3_complete16 0
+#endif
+
+#ifdef SQLITE_OMIT_DECLTYPE
+# define sqlite3_column_decltype16      0
+# define sqlite3_column_decltype        0
+#endif
+
+#ifdef SQLITE_OMIT_PROGRESS_CALLBACK
+# define sqlite3_progress_handler 0
+#endif
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+# define sqlite3_create_module 0
+# define sqlite3_create_module_v2 0
+# define sqlite3_declare_vtab 0
+# define sqlite3_vtab_config 0
+# define sqlite3_vtab_on_conflict 0
+# define sqlite3_vtab_collation 0
+#endif
+
+#ifdef SQLITE_OMIT_SHARED_CACHE
+# define sqlite3_enable_shared_cache 0
+#endif
+
+#if defined(SQLITE_OMIT_TRACE) || defined(SQLITE_OMIT_DEPRECATED)
+# define sqlite3_profile       0
+# define sqlite3_trace         0
+#endif
+
+#ifdef SQLITE_OMIT_GET_TABLE
+# define sqlite3_free_table    0
+# define sqlite3_get_table     0
+#endif
+
+#ifdef SQLITE_OMIT_INCRBLOB
+#define sqlite3_bind_zeroblob  0
+#define sqlite3_blob_bytes     0
+#define sqlite3_blob_close     0
+#define sqlite3_blob_open      0
+#define sqlite3_blob_read      0
+#define sqlite3_blob_write     0
+#define sqlite3_blob_reopen    0
+#endif
+
+#if defined(SQLITE_OMIT_TRACE)
+# define sqlite3_trace_v2      0
+#endif
+
+/*
+** The following structure contains pointers to all SQLite API routines.
+** A pointer to this structure is passed into extensions when they are
+** loaded so that the extension can make calls back into the SQLite
+** library.
+**
+** When adding new APIs, add them to the bottom of this structure
+** in order to preserve backwards compatibility.
+**
+** Extensions that use newer APIs should first call the
+** sqlite3_libversion_number() to make sure that the API they
+** intend to use is supported by the library.  Extensions should
+** also check to make sure that the pointer to the function is
+** not NULL before calling it.
+*/
+static const sqlite3_api_routines sqlite3Apis = {
+  sqlite3_aggregate_context,
+#ifndef SQLITE_OMIT_DEPRECATED
+  sqlite3_aggregate_count,
+#else
+  0,
+#endif
+  sqlite3_bind_blob,
+  sqlite3_bind_double,
+  sqlite3_bind_int,
+  sqlite3_bind_int64,
+  sqlite3_bind_null,
+  sqlite3_bind_parameter_count,
+  sqlite3_bind_parameter_index,
+  sqlite3_bind_parameter_name,
+  sqlite3_bind_text,
+  sqlite3_bind_text16,
+  sqlite3_bind_value,
+  sqlite3_busy_handler,
+  sqlite3_busy_timeout,
+  sqlite3_changes,
+  sqlite3_close,
+  sqlite3_collation_needed,
+  sqlite3_collation_needed16,
+  sqlite3_column_blob,
+  sqlite3_column_bytes,
+  sqlite3_column_bytes16,
+  sqlite3_column_count,
+  sqlite3_column_database_name,
+  sqlite3_column_database_name16,
+  sqlite3_column_decltype,
+  sqlite3_column_decltype16,
+  sqlite3_column_double,
+  sqlite3_column_int,
+  sqlite3_column_int64,
+  sqlite3_column_name,
+  sqlite3_column_name16,
+  sqlite3_column_origin_name,
+  sqlite3_column_origin_name16,
+  sqlite3_column_table_name,
+  sqlite3_column_table_name16,
+  sqlite3_column_text,
+  sqlite3_column_text16,
+  sqlite3_column_type,
+  sqlite3_column_value,
+  sqlite3_commit_hook,
+  sqlite3_complete,
+  sqlite3_complete16,
+  sqlite3_create_collation,
+  sqlite3_create_collation16,
+  sqlite3_create_function,
+  sqlite3_create_function16,
+  sqlite3_create_module,
+  sqlite3_data_count,
+  sqlite3_db_handle,
+  sqlite3_declare_vtab,
+  sqlite3_enable_shared_cache,
+  sqlite3_errcode,
+  sqlite3_errmsg,
+  sqlite3_errmsg16,
+  sqlite3_exec,
+#ifndef SQLITE_OMIT_DEPRECATED
+  sqlite3_expired,
+#else
+  0,
+#endif
+  sqlite3_finalize,
+  sqlite3_free,
+  sqlite3_free_table,
+  sqlite3_get_autocommit,
+  sqlite3_get_auxdata,
+  sqlite3_get_table,
+  0,     /* Was sqlite3_global_recover(), but that function is deprecated */
+  sqlite3_interrupt,
+  sqlite3_last_insert_rowid,
+  sqlite3_libversion,
+  sqlite3_libversion_number,
+  sqlite3_malloc,
+  sqlite3_mprintf,
+  sqlite3_open,
+  sqlite3_open16,
+  sqlite3_prepare,
+  sqlite3_prepare16,
+  sqlite3_profile,
+  sqlite3_progress_handler,
+  sqlite3_realloc,
+  sqlite3_reset,
+  sqlite3_result_blob,
+  sqlite3_result_double,
+  sqlite3_result_error,
+  sqlite3_result_error16,
+  sqlite3_result_int,
+  sqlite3_result_int64,
+  sqlite3_result_null,
+  sqlite3_result_text,
+  sqlite3_result_text16,
+  sqlite3_result_text16be,
+  sqlite3_result_text16le,
+  sqlite3_result_value,
+  sqlite3_rollback_hook,
+  sqlite3_set_authorizer,
+  sqlite3_set_auxdata,
+  sqlite3_snprintf,
+  sqlite3_step,
+  sqlite3_table_column_metadata,
+#ifndef SQLITE_OMIT_DEPRECATED
+  sqlite3_thread_cleanup,
+#else
+  0,
+#endif
+  sqlite3_total_changes,
+  sqlite3_trace,
+#ifndef SQLITE_OMIT_DEPRECATED
+  sqlite3_transfer_bindings,
+#else
+  0,
+#endif
+  sqlite3_update_hook,
+  sqlite3_user_data,
+  sqlite3_value_blob,
+  sqlite3_value_bytes,
+  sqlite3_value_bytes16,
+  sqlite3_value_double,
+  sqlite3_value_int,
+  sqlite3_value_int64,
+  sqlite3_value_numeric_type,
+  sqlite3_value_text,
+  sqlite3_value_text16,
+  sqlite3_value_text16be,
+  sqlite3_value_text16le,
+  sqlite3_value_type,
+  sqlite3_vmprintf,
+  /*
+  ** The original API set ends here.  All extensions can call any
+  ** of the APIs above provided that the pointer is not NULL.  But
+  ** before calling APIs that follow, extension should check the
+  ** sqlite3_libversion_number() to make sure they are dealing with
+  ** a library that is new enough to support that API.
+  *************************************************************************
+  */
+  sqlite3_overload_function,
+
+  /*
+  ** Added after 3.3.13
+  */
+  sqlite3_prepare_v2,
+  sqlite3_prepare16_v2,
+  sqlite3_clear_bindings,
+
+  /*
+  ** Added for 3.4.1
+  */
+  sqlite3_create_module_v2,
+
+  /*
+  ** Added for 3.5.0
+  */
+  sqlite3_bind_zeroblob,
+  sqlite3_blob_bytes,
+  sqlite3_blob_close,
+  sqlite3_blob_open,
+  sqlite3_blob_read,
+  sqlite3_blob_write,
+  sqlite3_create_collation_v2,
+  sqlite3_file_control,
+  sqlite3_memory_highwater,
+  sqlite3_memory_used,
+#ifdef SQLITE_MUTEX_OMIT
+  0,
+  0,
+  0,
+  0,
+  0,
+#else
+  sqlite3_mutex_alloc,
+  sqlite3_mutex_enter,
+  sqlite3_mutex_free,
+  sqlite3_mutex_leave,
+  sqlite3_mutex_try,
+#endif
+  sqlite3_open_v2,
+  sqlite3_release_memory,
+  sqlite3_result_error_nomem,
+  sqlite3_result_error_toobig,
+  sqlite3_sleep,
+  sqlite3_soft_heap_limit,
+  sqlite3_vfs_find,
+  sqlite3_vfs_register,
+  sqlite3_vfs_unregister,
+
+  /*
+  ** Added for 3.5.8
+  */
+  sqlite3_threadsafe,
+  sqlite3_result_zeroblob,
+  sqlite3_result_error_code,
+  sqlite3_test_control,
+  sqlite3_randomness,
+  sqlite3_context_db_handle,
+
+  /*
+  ** Added for 3.6.0
+  */
+  sqlite3_extended_result_codes,
+  sqlite3_limit,
+  sqlite3_next_stmt,
+  sqlite3_sql,
+  sqlite3_status,
+
+  /*
+  ** Added for 3.7.4
+  */
+  sqlite3_backup_finish,
+  sqlite3_backup_init,
+  sqlite3_backup_pagecount,
+  sqlite3_backup_remaining,
+  sqlite3_backup_step,
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+  sqlite3_compileoption_get,
+  sqlite3_compileoption_used,
+#else
+  0,
+  0,
+#endif
+  sqlite3_create_function_v2,
+  sqlite3_db_config,
+  sqlite3_db_mutex,
+  sqlite3_db_status,
+  sqlite3_extended_errcode,
+  sqlite3_log,
+  sqlite3_soft_heap_limit64,
+  sqlite3_sourceid,
+  sqlite3_stmt_status,
+  sqlite3_strnicmp,
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+  sqlite3_unlock_notify,
+#else
+  0,
+#endif
+#ifndef SQLITE_OMIT_WAL
+  sqlite3_wal_autocheckpoint,
+  sqlite3_wal_checkpoint,
+  sqlite3_wal_hook,
+#else
+  0,
+  0,
+  0,
+#endif
+  sqlite3_blob_reopen,
+  sqlite3_vtab_config,
+  sqlite3_vtab_on_conflict,
+  sqlite3_close_v2,
+  sqlite3_db_filename,
+  sqlite3_db_readonly,
+  sqlite3_db_release_memory,
+  sqlite3_errstr,
+  sqlite3_stmt_busy,
+  sqlite3_stmt_readonly,
+  sqlite3_stricmp,
+  sqlite3_uri_boolean,
+  sqlite3_uri_int64,
+  sqlite3_uri_parameter,
+  sqlite3_vsnprintf,
+  sqlite3_wal_checkpoint_v2,
+  /* Version 3.8.7 and later */
+  sqlite3_auto_extension,
+  sqlite3_bind_blob64,
+  sqlite3_bind_text64,
+  sqlite3_cancel_auto_extension,
+  sqlite3_load_extension,
+  sqlite3_malloc64,
+  sqlite3_msize,
+  sqlite3_realloc64,
+  sqlite3_reset_auto_extension,
+  sqlite3_result_blob64,
+  sqlite3_result_text64,
+  sqlite3_strglob,
+  /* Version 3.8.11 and later */
+  (sqlite3_value*(*)(const sqlite3_value*))sqlite3_value_dup,
+  sqlite3_value_free,
+  sqlite3_result_zeroblob64,
+  sqlite3_bind_zeroblob64,
+  /* Version 3.9.0 and later */
+  sqlite3_value_subtype,
+  sqlite3_result_subtype,
+  /* Version 3.10.0 and later */
+  sqlite3_status64,
+  sqlite3_strlike,
+  sqlite3_db_cacheflush,
+  /* Version 3.12.0 and later */
+  sqlite3_system_errno,
+  /* Version 3.14.0 and later */
+  sqlite3_trace_v2,
+  sqlite3_expanded_sql,
+  /* Version 3.18.0 and later */
+  sqlite3_set_last_insert_rowid,
+  /* Version 3.20.0 and later */
+  sqlite3_prepare_v3,
+  sqlite3_prepare16_v3,
+  sqlite3_bind_pointer,
+  sqlite3_result_pointer,
+  sqlite3_value_pointer,
+  /* Version 3.22.0 and later */
+  sqlite3_vtab_nochange,
+  sqlite3_value_nochange,
+  sqlite3_vtab_collation,
+  /* Version 3.24.0 and later */
+  sqlite3_keyword_count,
+  sqlite3_keyword_name,
+  sqlite3_keyword_check,
+  sqlite3_str_new,
+  sqlite3_str_finish,
+  sqlite3_str_appendf,
+  sqlite3_str_vappendf,
+  sqlite3_str_append,
+  sqlite3_str_appendall,
+  sqlite3_str_appendchar,
+  sqlite3_str_reset,
+  sqlite3_str_errcode,
+  sqlite3_str_length,
+  sqlite3_str_value,
+  /* Version 3.25.0 and later */
+  sqlite3_create_window_function,
+  /* Version 3.26.0 and later */
+#ifdef SQLITE_ENABLE_NORMALIZE
+  sqlite3_normalized_sql,
+#else
+  0,
+#endif
+  /* Version 3.28.0 and later */
+  sqlite3_stmt_isexplain,
+  sqlite3_value_frombind,
+  /* Version 3.30.0 and later */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3_drop_modules,
+#else
+  0,
+#endif
+  /* Version 3.31.0 and later */
+  sqlite3_hard_heap_limit64,
+  sqlite3_uri_key,
+  sqlite3_filename_database,
+  sqlite3_filename_journal,
+  sqlite3_filename_wal,
+  /* Version 3.32.0 and later */
+  sqlite3_create_filename,
+  sqlite3_free_filename,
+  sqlite3_database_file_object,
+  /* Version 3.34.0 and later */
+  sqlite3_txn_state,
+  /* Version 3.36.1 and later */
+  sqlite3_changes64,
+  sqlite3_total_changes64,
+  /* Version 3.37.0 and later */
+  sqlite3_autovacuum_pages,
+  /* Version 3.38.0 and later */
+  sqlite3_error_offset,
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3_vtab_rhs_value,
+  sqlite3_vtab_distinct,
+  sqlite3_vtab_in,
+  sqlite3_vtab_in_first,
+  sqlite3_vtab_in_next,
+#else
+  0,
+  0,
+  0,
+  0,
+  0,
+#endif
+  /* Version 3.39.0 and later */
+#ifndef SQLITE_OMIT_DESERIALIZE
+  sqlite3_deserialize,
+  sqlite3_serialize,
+#else
+  0,
+  0,
+#endif
+  sqlite3_db_name,
+  /* Version 3.40.0 and later */
+  sqlite3_value_encoding,
+  /* Version 3.41.0 and later */
+  sqlite3_is_interrupted,
+  /* Version 3.43.0 and later */
+  sqlite3_stmt_explain,
+  /* Version 3.44.0 and later */
+  sqlite3_get_clientdata,
+  sqlite3_set_clientdata
+};
+
+/* True if x is the directory separator character
+*/
+#if SQLITE_OS_WIN
+# define DirSep(X)  ((X)=='/'||(X)=='\\')
+#else
+# define DirSep(X)  ((X)=='/')
+#endif
+
+/*
+** Attempt to load an SQLite extension library contained in the file
+** zFile.  The entry point is zProc.  zProc may be 0 in which case a
+** default entry point name (sqlite3_extension_init) is used.  Use
+** of the default name is recommended.
+**
+** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
+**
+** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
+** error message text.  The calling function should free this memory
+** by calling sqlite3DbFree(db, ).
+*/
+static int sqlite3LoadExtension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+){
+  sqlite3_vfs *pVfs = db->pVfs;
+  void *handle;
+  sqlite3_loadext_entry xInit;
+  char *zErrmsg = 0;
+  const char *zEntry;
+  char *zAltEntry = 0;
+  void **aHandle;
+  u64 nMsg = strlen(zFile);
+  int ii;
+  int rc;
+
+  /* Shared library endings to try if zFile cannot be loaded as written */
+  static const char *azEndings[] = {
+#if SQLITE_OS_WIN
+     "dll"
+#elif defined(__APPLE__)
+     "dylib"
+#else
+     "so"
+#endif
+  };
+
+
+  if( pzErrMsg ) *pzErrMsg = 0;
+
+  /* Ticket #1863.  To avoid a creating security problems for older
+  ** applications that relink against newer versions of SQLite, the
+  ** ability to run load_extension is turned off by default.  One
+  ** must call either sqlite3_enable_load_extension(db) or
+  ** sqlite3_db_config(db, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, 0)
+  ** to turn on extension loading.
+  */
+  if( (db->flags & SQLITE_LoadExtension)==0 ){
+    if( pzErrMsg ){
+      *pzErrMsg = sqlite3_mprintf("not authorized");
+    }
+    return SQLITE_ERROR;
+  }
+
+  zEntry = zProc ? zProc : "sqlite3_extension_init";
+
+  /* tag-20210611-1.  Some dlopen() implementations will segfault if given
+  ** an oversize filename.  Most filesystems have a pathname limit of 4K,
+  ** so limit the extension filename length to about twice that.
+  ** https://sqlite.org/forum/forumpost/08a0d6d9bf
+  **
+  ** Later (2023-03-25): Save an extra 6 bytes for the filename suffix.
+  ** See https://sqlite.org/forum/forumpost/24083b579d.
+  */
+  if( nMsg>SQLITE_MAX_PATHLEN ) goto extension_not_found;
+
+  /* Do not allow sqlite3_load_extension() to link to a copy of the
+  ** running application, by passing in an empty filename. */
+  if( nMsg==0 ) goto extension_not_found;
+
+  handle = sqlite3OsDlOpen(pVfs, zFile);
+#if SQLITE_OS_UNIX || SQLITE_OS_WIN
+  for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
+    char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
+    if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
+    if( nMsg+strlen(azEndings[ii])+1<=SQLITE_MAX_PATHLEN ){
+      handle = sqlite3OsDlOpen(pVfs, zAltFile);
+    }
+    sqlite3_free(zAltFile);
+  }
+#endif
+  if( handle==0 ) goto extension_not_found;
+  xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
+
+  /* If no entry point was specified and the default legacy
+  ** entry point name "sqlite3_extension_init" was not found, then
+  ** construct an entry point name "sqlite3_X_init" where the X is
+  ** replaced by the lowercase value of every ASCII alphabetic
+  ** character in the filename after the last "/" upto the first ".",
+  ** and eliding the first three characters if they are "lib".
+  ** Examples:
+  **
+  **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
+  **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
+  */
+  if( xInit==0 && zProc==0 ){
+    int iFile, iEntry, c;
+    int ncFile = sqlite3Strlen30(zFile);
+    zAltEntry = sqlite3_malloc64(ncFile+30);
+    if( zAltEntry==0 ){
+      sqlite3OsDlClose(pVfs, handle);
+      return SQLITE_NOMEM_BKPT;
+    }
+    memcpy(zAltEntry, "sqlite3_", 8);
+    for(iFile=ncFile-1; iFile>=0 && !DirSep(zFile[iFile]); iFile--){}
+    iFile++;
+    if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
+    for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
+      if( sqlite3Isalpha(c) ){
+        zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
+      }
+    }
+    memcpy(zAltEntry+iEntry, "_init", 6);
+    zEntry = zAltEntry;
+    xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
+  }
+  if( xInit==0 ){
+    if( pzErrMsg ){
+      nMsg += strlen(zEntry) + 300;
+      *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
+      if( zErrmsg ){
+        assert( nMsg<0x7fffffff );  /* zErrmsg would be NULL if not so */
+        sqlite3_snprintf((int)nMsg, zErrmsg,
+            "no entry point [%s] in shared library [%s]", zEntry, zFile);
+        sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
+      }
+    }
+    sqlite3OsDlClose(pVfs, handle);
+    sqlite3_free(zAltEntry);
+    return SQLITE_ERROR;
+  }
+  sqlite3_free(zAltEntry);
+  rc = xInit(db, &zErrmsg, &sqlite3Apis);
+  if( rc ){
+    if( rc==SQLITE_OK_LOAD_PERMANENTLY ) return SQLITE_OK;
+    if( pzErrMsg ){
+      *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
+    }
+    sqlite3_free(zErrmsg);
+    sqlite3OsDlClose(pVfs, handle);
+    return SQLITE_ERROR;
+  }
+
+  /* Append the new shared library handle to the db->aExtension array. */
+  aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
+  if( aHandle==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  if( db->nExtension>0 ){
+    memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
+  }
+  sqlite3DbFree(db, db->aExtension);
+  db->aExtension = aHandle;
+
+  db->aExtension[db->nExtension++] = handle;
+  return SQLITE_OK;
+
+extension_not_found:
+  if( pzErrMsg ){
+    nMsg += 300;
+    *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
+    if( zErrmsg ){
+      assert( nMsg<0x7fffffff );  /* zErrmsg would be NULL if not so */
+      sqlite3_snprintf((int)nMsg, zErrmsg,
+          "unable to open shared library [%.*s]", SQLITE_MAX_PATHLEN, zFile);
+      sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
+    }
+  }
+  return SQLITE_ERROR;
+}
+SQLITE_API int sqlite3_load_extension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+){
+  int rc;
+  sqlite3_mutex_enter(db->mutex);
+  rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Call this routine when the database connection is closing in order
+** to clean up loaded extensions
+*/
+SQLITE_PRIVATE void sqlite3CloseExtensions(sqlite3 *db){
+  int i;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nExtension; i++){
+    sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
+  }
+  sqlite3DbFree(db, db->aExtension);
+}
+
+/*
+** Enable or disable extension loading.  Extension loading is disabled by
+** default so as not to open security holes in older applications.
+*/
+SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( onoff ){
+    db->flags |= SQLITE_LoadExtension|SQLITE_LoadExtFunc;
+  }else{
+    db->flags &= ~(u64)(SQLITE_LoadExtension|SQLITE_LoadExtFunc);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#endif /* !defined(SQLITE_OMIT_LOAD_EXTENSION) */
+
+/*
+** The following object holds the list of automatically loaded
+** extensions.
+**
+** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MAIN
+** mutex must be held while accessing this list.
+*/
+typedef struct sqlite3AutoExtList sqlite3AutoExtList;
+static SQLITE_WSD struct sqlite3AutoExtList {
+  u32 nExt;              /* Number of entries in aExt[] */
+  void (**aExt)(void);   /* Pointers to the extension init functions */
+} sqlite3Autoext = { 0, 0 };
+
+/* The "wsdAutoext" macro will resolve to the autoextension
+** state vector.  If writable static data is unsupported on the target,
+** we have to locate the state vector at run-time.  In the more common
+** case where writable static data is supported, wsdStat can refer directly
+** to the "sqlite3Autoext" state vector declared above.
+*/
+#ifdef SQLITE_OMIT_WSD
+# define wsdAutoextInit \
+  sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
+# define wsdAutoext x[0]
+#else
+# define wsdAutoextInit
+# define wsdAutoext sqlite3Autoext
+#endif
+
+
+/*
+** Register a statically linked extension that is automatically
+** loaded by every new database connection.
+*/
+SQLITE_API int sqlite3_auto_extension(
+  void (*xInit)(void)
+){
+  int rc = SQLITE_OK;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( xInit==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ){
+    return rc;
+  }else
+#endif
+  {
+    u32 i;
+#if SQLITE_THREADSAFE
+    sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+    wsdAutoextInit;
+    sqlite3_mutex_enter(mutex);
+    for(i=0; i<wsdAutoext.nExt; i++){
+      if( wsdAutoext.aExt[i]==xInit ) break;
+    }
+    if( i==wsdAutoext.nExt ){
+      u64 nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
+      void (**aNew)(void);
+      aNew = sqlite3_realloc64(wsdAutoext.aExt, nByte);
+      if( aNew==0 ){
+        rc = SQLITE_NOMEM_BKPT;
+      }else{
+        wsdAutoext.aExt = aNew;
+        wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
+        wsdAutoext.nExt++;
+      }
+    }
+    sqlite3_mutex_leave(mutex);
+    assert( (rc&0xff)==rc );
+    return rc;
+  }
+}
+
+/*
+** Cancel a prior call to sqlite3_auto_extension.  Remove xInit from the
+** set of routines that is invoked for each new database connection, if it
+** is currently on the list.  If xInit is not on the list, then this
+** routine is a no-op.
+**
+** Return 1 if xInit was found on the list and removed.  Return 0 if xInit
+** was not on the list.
+*/
+SQLITE_API int sqlite3_cancel_auto_extension(
+  void (*xInit)(void)
+){
+#if SQLITE_THREADSAFE
+  sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+  int i;
+  int n = 0;
+  wsdAutoextInit;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( xInit==0 ) return 0;
+#endif
+  sqlite3_mutex_enter(mutex);
+  for(i=(int)wsdAutoext.nExt-1; i>=0; i--){
+    if( wsdAutoext.aExt[i]==xInit ){
+      wsdAutoext.nExt--;
+      wsdAutoext.aExt[i] = wsdAutoext.aExt[wsdAutoext.nExt];
+      n++;
+      break;
+    }
+  }
+  sqlite3_mutex_leave(mutex);
+  return n;
+}
+
+/*
+** Reset the automatic extension loading mechanism.
+*/
+SQLITE_API void sqlite3_reset_auto_extension(void){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize()==SQLITE_OK )
+#endif
+  {
+#if SQLITE_THREADSAFE
+    sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+    wsdAutoextInit;
+    sqlite3_mutex_enter(mutex);
+    sqlite3_free(wsdAutoext.aExt);
+    wsdAutoext.aExt = 0;
+    wsdAutoext.nExt = 0;
+    sqlite3_mutex_leave(mutex);
+  }
+}
+
+/*
+** Load all automatic extensions.
+**
+** If anything goes wrong, set an error in the database connection.
+*/
+SQLITE_PRIVATE void sqlite3AutoLoadExtensions(sqlite3 *db){
+  u32 i;
+  int go = 1;
+  int rc;
+  sqlite3_loadext_entry xInit;
+
+  wsdAutoextInit;
+  if( wsdAutoext.nExt==0 ){
+    /* Common case: early out without every having to acquire a mutex */
+    return;
+  }
+  for(i=0; go; i++){
+    char *zErrmsg;
+#if SQLITE_THREADSAFE
+    sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+#ifdef SQLITE_OMIT_LOAD_EXTENSION
+    const sqlite3_api_routines *pThunk = 0;
+#else
+    const sqlite3_api_routines *pThunk = &sqlite3Apis;
+#endif
+    sqlite3_mutex_enter(mutex);
+    if( i>=wsdAutoext.nExt ){
+      xInit = 0;
+      go = 0;
+    }else{
+      xInit = (sqlite3_loadext_entry)wsdAutoext.aExt[i];
+    }
+    sqlite3_mutex_leave(mutex);
+    zErrmsg = 0;
+    if( xInit && (rc = xInit(db, &zErrmsg, pThunk))!=0 ){
+      sqlite3ErrorWithMsg(db, rc,
+            "automatic extension loading failed: %s", zErrmsg);
+      go = 0;
+    }
+    sqlite3_free(zErrmsg);
+  }
+}
+
+/************** End of loadext.c *********************************************/
+/************** Begin file pragma.c ******************************************/
+/*
+** 2003 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the PRAGMA command.
+*/
+/* #include "sqliteInt.h" */
+
+#if !defined(SQLITE_ENABLE_LOCKING_STYLE)
+#  if defined(__APPLE__)
+#    define SQLITE_ENABLE_LOCKING_STYLE 1
+#  else
+#    define SQLITE_ENABLE_LOCKING_STYLE 0
+#  endif
+#endif
+
+/***************************************************************************
+** The "pragma.h" include file is an automatically generated file that
+** that includes the PragType_XXXX macro definitions and the aPragmaName[]
+** object.  This ensures that the aPragmaName[] table is arranged in
+** lexicographical order to facility a binary search of the pragma name.
+** Do not edit pragma.h directly.  Edit and rerun the script in at
+** ../tool/mkpragmatab.tcl. */
+/************** Include pragma.h in the middle of pragma.c *******************/
+/************** Begin file pragma.h ******************************************/
+/* DO NOT EDIT!
+** This file is automatically generated by the script at
+** ../tool/mkpragmatab.tcl.  To update the set of pragmas, edit
+** that script and rerun it.
+*/
+
+/* The various pragma types */
+#define PragTyp_ACTIVATE_EXTENSIONS            0
+#define PragTyp_ANALYSIS_LIMIT                 1
+#define PragTyp_HEADER_VALUE                   2
+#define PragTyp_AUTO_VACUUM                    3
+#define PragTyp_FLAG                           4
+#define PragTyp_BUSY_TIMEOUT                   5
+#define PragTyp_CACHE_SIZE                     6
+#define PragTyp_CACHE_SPILL                    7
+#define PragTyp_CASE_SENSITIVE_LIKE            8
+#define PragTyp_COLLATION_LIST                 9
+#define PragTyp_COMPILE_OPTIONS               10
+#define PragTyp_DATA_STORE_DIRECTORY          11
+#define PragTyp_DATABASE_LIST                 12
+#define PragTyp_DEFAULT_CACHE_SIZE            13
+#define PragTyp_ENCODING                      14
+#define PragTyp_FOREIGN_KEY_CHECK             15
+#define PragTyp_FOREIGN_KEY_LIST              16
+#define PragTyp_FUNCTION_LIST                 17
+#define PragTyp_HARD_HEAP_LIMIT               18
+#define PragTyp_INCREMENTAL_VACUUM            19
+#define PragTyp_INDEX_INFO                    20
+#define PragTyp_INDEX_LIST                    21
+#define PragTyp_INTEGRITY_CHECK               22
+#define PragTyp_JOURNAL_MODE                  23
+#define PragTyp_JOURNAL_SIZE_LIMIT            24
+#define PragTyp_LOCK_PROXY_FILE               25
+#define PragTyp_LOCKING_MODE                  26
+#define PragTyp_PAGE_COUNT                    27
+#define PragTyp_MMAP_SIZE                     28
+#define PragTyp_MODULE_LIST                   29
+#define PragTyp_OPTIMIZE                      30
+#define PragTyp_PAGE_SIZE                     31
+#define PragTyp_PRAGMA_LIST                   32
+#define PragTyp_SECURE_DELETE                 33
+#define PragTyp_SHRINK_MEMORY                 34
+#define PragTyp_SOFT_HEAP_LIMIT               35
+#define PragTyp_SYNCHRONOUS                   36
+#define PragTyp_TABLE_INFO                    37
+#define PragTyp_TABLE_LIST                    38
+#define PragTyp_TEMP_STORE                    39
+#define PragTyp_TEMP_STORE_DIRECTORY          40
+#define PragTyp_THREADS                       41
+#define PragTyp_WAL_AUTOCHECKPOINT            42
+#define PragTyp_WAL_CHECKPOINT                43
+#define PragTyp_LOCK_STATUS                   44
+#define PragTyp_STATS                         45
+
+/* Property flags associated with various pragma. */
+#define PragFlg_NeedSchema 0x01 /* Force schema load before running */
+#define PragFlg_NoColumns  0x02 /* OP_ResultRow called with zero columns */
+#define PragFlg_NoColumns1 0x04 /* zero columns if RHS argument is present */
+#define PragFlg_ReadOnly   0x08 /* Read-only HEADER_VALUE */
+#define PragFlg_Result0    0x10 /* Acts as query when no argument */
+#define PragFlg_Result1    0x20 /* Acts as query when has one argument */
+#define PragFlg_SchemaOpt  0x40 /* Schema restricts name search if present */
+#define PragFlg_SchemaReq  0x80 /* Schema required - "main" is default */
+
+/* Names of columns for pragmas that return multi-column result
+** or that return single-column results where the name of the
+** result column is different from the name of the pragma
+*/
+static const char *const pragCName[] = {
+  /*   0 */ "id",          /* Used by: foreign_key_list */
+  /*   1 */ "seq",
+  /*   2 */ "table",
+  /*   3 */ "from",
+  /*   4 */ "to",
+  /*   5 */ "on_update",
+  /*   6 */ "on_delete",
+  /*   7 */ "match",
+  /*   8 */ "cid",         /* Used by: table_xinfo */
+  /*   9 */ "name",
+  /*  10 */ "type",
+  /*  11 */ "notnull",
+  /*  12 */ "dflt_value",
+  /*  13 */ "pk",
+  /*  14 */ "hidden",
+                           /* table_info reuses 8 */
+  /*  15 */ "name",        /* Used by: function_list */
+  /*  16 */ "builtin",
+  /*  17 */ "type",
+  /*  18 */ "enc",
+  /*  19 */ "narg",
+  /*  20 */ "flags",
+  /*  21 */ "schema",      /* Used by: table_list */
+  /*  22 */ "name",
+  /*  23 */ "type",
+  /*  24 */ "ncol",
+  /*  25 */ "wr",
+  /*  26 */ "strict",
+  /*  27 */ "seqno",       /* Used by: index_xinfo */
+  /*  28 */ "cid",
+  /*  29 */ "name",
+  /*  30 */ "desc",
+  /*  31 */ "coll",
+  /*  32 */ "key",
+  /*  33 */ "seq",         /* Used by: index_list */
+  /*  34 */ "name",
+  /*  35 */ "unique",
+  /*  36 */ "origin",
+  /*  37 */ "partial",
+  /*  38 */ "tbl",         /* Used by: stats */
+  /*  39 */ "idx",
+  /*  40 */ "wdth",
+  /*  41 */ "hght",
+  /*  42 */ "flgs",
+  /*  43 */ "table",       /* Used by: foreign_key_check */
+  /*  44 */ "rowid",
+  /*  45 */ "parent",
+  /*  46 */ "fkid",
+  /*  47 */ "busy",        /* Used by: wal_checkpoint */
+  /*  48 */ "log",
+  /*  49 */ "checkpointed",
+  /*  50 */ "seq",         /* Used by: database_list */
+  /*  51 */ "name",
+  /*  52 */ "file",
+                           /* index_info reuses 27 */
+  /*  53 */ "database",    /* Used by: lock_status */
+  /*  54 */ "status",
+                           /* collation_list reuses 33 */
+  /*  55 */ "cache_size",  /* Used by: default_cache_size */
+                           /* module_list pragma_list reuses 9 */
+  /*  56 */ "timeout",     /* Used by: busy_timeout */
+};
+
+/* Definitions of all built-in pragmas */
+typedef struct PragmaName {
+  const char *const zName; /* Name of pragma */
+  u8 ePragTyp;             /* PragTyp_XXX value */
+  u8 mPragFlg;             /* Zero or more PragFlg_XXX values */
+  u8 iPragCName;           /* Start of column names in pragCName[] */
+  u8 nPragCName;           /* Num of col names. 0 means use pragma name */
+  u64 iArg;                /* Extra argument */
+} PragmaName;
+static const PragmaName aPragmaName[] = {
+#if defined(SQLITE_ENABLE_CEROD)
+ {/* zName:     */ "activate_extensions",
+  /* ePragTyp:  */ PragTyp_ACTIVATE_EXTENSIONS,
+  /* ePragFlg:  */ 0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+ {/* zName:     */ "analysis_limit",
+  /* ePragTyp:  */ PragTyp_ANALYSIS_LIMIT,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "application_id",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_NoColumns1|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_APPLICATION_ID },
+#endif
+#if !defined(SQLITE_OMIT_AUTOVACUUM)
+ {/* zName:     */ "auto_vacuum",
+  /* ePragTyp:  */ PragTyp_AUTO_VACUUM,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if !defined(SQLITE_OMIT_AUTOMATIC_INDEX)
+ {/* zName:     */ "automatic_index",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_AutoIndex },
+#endif
+#endif
+ {/* zName:     */ "busy_timeout",
+  /* ePragTyp:  */ PragTyp_BUSY_TIMEOUT,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 56, 1,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "cache_size",
+  /* ePragTyp:  */ PragTyp_CACHE_SIZE,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "cache_spill",
+  /* ePragTyp:  */ PragTyp_CACHE_SPILL,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_CASE_SENSITIVE_LIKE_PRAGMA)
+ {/* zName:     */ "case_sensitive_like",
+  /* ePragTyp:  */ PragTyp_CASE_SENSITIVE_LIKE,
+  /* ePragFlg:  */ PragFlg_NoColumns,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+ {/* zName:     */ "cell_size_check",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_CellSizeCk },
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "checkpoint_fullfsync",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_CkptFullFSync },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+ {/* zName:     */ "collation_list",
+  /* ePragTyp:  */ PragTyp_COLLATION_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 33, 2,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_COMPILEOPTION_DIAGS)
+ {/* zName:     */ "compile_options",
+  /* ePragTyp:  */ PragTyp_COMPILE_OPTIONS,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "count_changes",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_CountRows },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && SQLITE_OS_WIN
+ {/* zName:     */ "data_store_directory",
+  /* ePragTyp:  */ PragTyp_DATA_STORE_DIRECTORY,
+  /* ePragFlg:  */ PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "data_version",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_ReadOnly|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_DATA_VERSION },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+ {/* zName:     */ "database_list",
+  /* ePragTyp:  */ PragTyp_DATABASE_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 50, 3,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)
+ {/* zName:     */ "default_cache_size",
+  /* ePragTyp:  */ PragTyp_DEFAULT_CACHE_SIZE,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 55, 1,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+ {/* zName:     */ "defer_foreign_keys",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_DeferFKs },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "empty_result_callbacks",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_NullCallback },
+#endif
+#if !defined(SQLITE_OMIT_UTF16)
+ {/* zName:     */ "encoding",
+  /* ePragTyp:  */ PragTyp_ENCODING,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+ {/* zName:     */ "foreign_key_check",
+  /* ePragTyp:  */ PragTyp_FOREIGN_KEY_CHECK,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 43, 4,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FOREIGN_KEY)
+ {/* zName:     */ "foreign_key_list",
+  /* ePragTyp:  */ PragTyp_FOREIGN_KEY_LIST,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 0, 8,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+ {/* zName:     */ "foreign_keys",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ForeignKeys },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "freelist_count",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_ReadOnly|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_FREE_PAGE_COUNT },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "full_column_names",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_FullColNames },
+ {/* zName:     */ "fullfsync",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_FullFSync },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+#if !defined(SQLITE_OMIT_INTROSPECTION_PRAGMAS)
+ {/* zName:     */ "function_list",
+  /* ePragTyp:  */ PragTyp_FUNCTION_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 15, 6,
+  /* iArg:      */ 0 },
+#endif
+#endif
+ {/* zName:     */ "hard_heap_limit",
+  /* ePragTyp:  */ PragTyp_HARD_HEAP_LIMIT,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if !defined(SQLITE_OMIT_CHECK)
+ {/* zName:     */ "ignore_check_constraints",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_IgnoreChecks },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_AUTOVACUUM)
+ {/* zName:     */ "incremental_vacuum",
+  /* ePragTyp:  */ PragTyp_INCREMENTAL_VACUUM,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_NoColumns,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+ {/* zName:     */ "index_info",
+  /* ePragTyp:  */ PragTyp_INDEX_INFO,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 27, 3,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "index_list",
+  /* ePragTyp:  */ PragTyp_INDEX_LIST,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 33, 5,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "index_xinfo",
+  /* ePragTyp:  */ PragTyp_INDEX_INFO,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 27, 6,
+  /* iArg:      */ 1 },
+#endif
+#if !defined(SQLITE_OMIT_INTEGRITY_CHECK)
+ {/* zName:     */ "integrity_check",
+  /* ePragTyp:  */ PragTyp_INTEGRITY_CHECK,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "journal_mode",
+  /* ePragTyp:  */ PragTyp_JOURNAL_MODE,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "journal_size_limit",
+  /* ePragTyp:  */ PragTyp_JOURNAL_SIZE_LIMIT,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "legacy_alter_table",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_LegacyAlter },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && SQLITE_ENABLE_LOCKING_STYLE
+ {/* zName:     */ "lock_proxy_file",
+  /* ePragTyp:  */ PragTyp_LOCK_PROXY_FILE,
+  /* ePragFlg:  */ PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+ {/* zName:     */ "lock_status",
+  /* ePragTyp:  */ PragTyp_LOCK_STATUS,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 53, 2,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "locking_mode",
+  /* ePragTyp:  */ PragTyp_LOCKING_MODE,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "max_page_count",
+  /* ePragTyp:  */ PragTyp_PAGE_COUNT,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "mmap_size",
+  /* ePragTyp:  */ PragTyp_MMAP_SIZE,
+  /* ePragFlg:  */ 0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+#if !defined(SQLITE_OMIT_VIRTUALTABLE)
+#if !defined(SQLITE_OMIT_INTROSPECTION_PRAGMAS)
+ {/* zName:     */ "module_list",
+  /* ePragTyp:  */ PragTyp_MODULE_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 9, 1,
+  /* iArg:      */ 0 },
+#endif
+#endif
+#endif
+ {/* zName:     */ "optimize",
+  /* ePragTyp:  */ PragTyp_OPTIMIZE,
+  /* ePragFlg:  */ PragFlg_Result1|PragFlg_NeedSchema,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "page_count",
+  /* ePragTyp:  */ PragTyp_PAGE_COUNT,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "page_size",
+  /* ePragTyp:  */ PragTyp_PAGE_SIZE,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if defined(SQLITE_DEBUG)
+ {/* zName:     */ "parser_trace",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ParserTrace },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_INTROSPECTION_PRAGMAS)
+ {/* zName:     */ "pragma_list",
+  /* ePragTyp:  */ PragTyp_PRAGMA_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 9, 1,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "query_only",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_QueryOnly },
+#endif
+#if !defined(SQLITE_OMIT_INTEGRITY_CHECK)
+ {/* zName:     */ "quick_check",
+  /* ePragTyp:  */ PragTyp_INTEGRITY_CHECK,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "read_uncommitted",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ReadUncommit },
+ {/* zName:     */ "recursive_triggers",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_RecTriggers },
+ {/* zName:     */ "reverse_unordered_selects",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ReverseOrder },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "schema_version",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_NoColumns1|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_SCHEMA_VERSION },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "secure_delete",
+  /* ePragTyp:  */ PragTyp_SECURE_DELETE,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "short_column_names",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ShortColNames },
+#endif
+ {/* zName:     */ "shrink_memory",
+  /* ePragTyp:  */ PragTyp_SHRINK_MEMORY,
+  /* ePragFlg:  */ PragFlg_NoColumns,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "soft_heap_limit",
+  /* ePragTyp:  */ PragTyp_SOFT_HEAP_LIMIT,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if defined(SQLITE_DEBUG)
+ {/* zName:     */ "sql_trace",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_SqlTrace },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS) && defined(SQLITE_DEBUG)
+ {/* zName:     */ "stats",
+  /* ePragTyp:  */ PragTyp_STATS,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 38, 5,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "synchronous",
+  /* ePragTyp:  */ PragTyp_SYNCHRONOUS,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+ {/* zName:     */ "table_info",
+  /* ePragTyp:  */ PragTyp_TABLE_INFO,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 8, 6,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "table_list",
+  /* ePragTyp:  */ PragTyp_TABLE_LIST,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1,
+  /* ColNames:  */ 21, 6,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "table_xinfo",
+  /* ePragTyp:  */ PragTyp_TABLE_INFO,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 8, 7,
+  /* iArg:      */ 1 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "temp_store",
+  /* ePragTyp:  */ PragTyp_TEMP_STORE,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "temp_store_directory",
+  /* ePragTyp:  */ PragTyp_TEMP_STORE_DIRECTORY,
+  /* ePragFlg:  */ PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+ {/* zName:     */ "threads",
+  /* ePragTyp:  */ PragTyp_THREADS,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "trusted_schema",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_TrustedSchema },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "user_version",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_NoColumns1|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_USER_VERSION },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if defined(SQLITE_DEBUG)
+ {/* zName:     */ "vdbe_addoptrace",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_VdbeAddopTrace },
+ {/* zName:     */ "vdbe_debug",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_SqlTrace|SQLITE_VdbeListing|SQLITE_VdbeTrace },
+ {/* zName:     */ "vdbe_eqp",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_VdbeEQP },
+ {/* zName:     */ "vdbe_listing",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_VdbeListing },
+ {/* zName:     */ "vdbe_trace",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_VdbeTrace },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_WAL)
+ {/* zName:     */ "wal_autocheckpoint",
+  /* ePragTyp:  */ PragTyp_WAL_AUTOCHECKPOINT,
+  /* ePragFlg:  */ 0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "wal_checkpoint",
+  /* ePragTyp:  */ PragTyp_WAL_CHECKPOINT,
+  /* ePragFlg:  */ PragFlg_NeedSchema,
+  /* ColNames:  */ 47, 3,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "writable_schema",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_WriteSchema|SQLITE_NoSchemaError },
+#endif
+};
+/* Number of pragmas: 68 on by default, 78 total. */
+
+/************** End of pragma.h **********************************************/
+/************** Continuing where we left off in pragma.c *********************/
+
+/*
+** When the 0x10 bit of PRAGMA optimize is set, any ANALYZE commands
+** will be run with an analysis_limit set to the lessor of the value of
+** the following macro or to the actual analysis_limit if it is non-zero,
+** in order to prevent PRAGMA optimize from running for too long.
+**
+** The value of 2000 is chosen emperically so that the worst-case run-time
+** for PRAGMA optimize does not exceed 100 milliseconds against a variety
+** of test databases on a RaspberryPI-4 compiled using -Os and without
+** -DSQLITE_DEBUG.  Of course, your mileage may vary.  For the purpose of
+** this paragraph, "worst-case" means that ANALYZE ends up being
+** run on every table in the database.  The worst case typically only
+** happens if PRAGMA optimize is run on a database file for which ANALYZE
+** has not been previously run and the 0x10000 flag is included so that
+** all tables are analyzed.  The usual case for PRAGMA optimize is that
+** no ANALYZE commands will be run at all, or if any ANALYZE happens it
+** will be against a single table, so that expected timing for PRAGMA
+** optimize on a PI-4 is more like 1 millisecond or less with the 0x10000
+** flag or less than 100 microseconds without the 0x10000 flag.
+**
+** An analysis limit of 2000 is almost always sufficient for the query
+** planner to fully characterize an index.  The additional accuracy from
+** a larger analysis is not usually helpful.
+*/
+#ifndef SQLITE_DEFAULT_OPTIMIZE_LIMIT
+# define SQLITE_DEFAULT_OPTIMIZE_LIMIT 2000
+#endif
+
+/*
+** Interpret the given string as a safety level.  Return 0 for OFF,
+** 1 for ON or NORMAL, 2 for FULL, and 3 for EXTRA.  Return 1 for an empty or
+** unrecognized string argument.  The FULL and EXTRA option is disallowed
+** if the omitFull parameter it 1.
+**
+** Note that the values returned are one less that the values that
+** should be passed into sqlite3BtreeSetSafetyLevel().  The is done
+** to support legacy SQL code.  The safety level used to be boolean
+** and older scripts may have used numbers 0 for OFF and 1 for ON.
+*/
+static u8 getSafetyLevel(const char *z, int omitFull, u8 dflt){
+                             /* 123456789 123456789 123 */
+  static const char zText[] = "onoffalseyestruextrafull";
+  static const u8 iOffset[] = {0, 1, 2,  4,    9,  12,  15,   20};
+  static const u8 iLength[] = {2, 2, 3,  5,    3,   4,   5,    4};
+  static const u8 iValue[] =  {1, 0, 0,  0,    1,   1,   3,    2};
+                            /* on no off false yes true extra full */
+  int i, n;
+  if( sqlite3Isdigit(*z) ){
+    return (u8)sqlite3Atoi(z);
+  }
+  n = sqlite3Strlen30(z);
+  for(i=0; i<ArraySize(iLength); i++){
+    if( iLength[i]==n && sqlite3StrNICmp(&zText[iOffset[i]],z,n)==0
+     && (!omitFull || iValue[i]<=1)
+    ){
+      return iValue[i];
+    }
+  }
+  return dflt;
+}
+
+/*
+** Interpret the given string as a boolean value.
+*/
+SQLITE_PRIVATE u8 sqlite3GetBoolean(const char *z, u8 dflt){
+  return getSafetyLevel(z,1,dflt)!=0;
+}
+
+/* The sqlite3GetBoolean() function is used by other modules but the
+** remainder of this file is specific to PRAGMA processing.  So omit
+** the rest of the file if PRAGMAs are omitted from the build.
+*/
+#if !defined(SQLITE_OMIT_PRAGMA)
+
+/*
+** Interpret the given string as a locking mode value.
+*/
+static int getLockingMode(const char *z){
+  if( z ){
+    if( 0==sqlite3StrICmp(z, "exclusive") ) return PAGER_LOCKINGMODE_EXCLUSIVE;
+    if( 0==sqlite3StrICmp(z, "normal") ) return PAGER_LOCKINGMODE_NORMAL;
+  }
+  return PAGER_LOCKINGMODE_QUERY;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Interpret the given string as an auto-vacuum mode value.
+**
+** The following strings, "none", "full" and "incremental" are
+** acceptable, as are their numeric equivalents: 0, 1 and 2 respectively.
+*/
+static int getAutoVacuum(const char *z){
+  int i;
+  if( 0==sqlite3StrICmp(z, "none") ) return BTREE_AUTOVACUUM_NONE;
+  if( 0==sqlite3StrICmp(z, "full") ) return BTREE_AUTOVACUUM_FULL;
+  if( 0==sqlite3StrICmp(z, "incremental") ) return BTREE_AUTOVACUUM_INCR;
+  i = sqlite3Atoi(z);
+  return (u8)((i>=0&&i<=2)?i:0);
+}
+#endif /* ifndef SQLITE_OMIT_AUTOVACUUM */
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+/*
+** Interpret the given string as a temp db location. Return 1 for file
+** backed temporary databases, 2 for the Red-Black tree in memory database
+** and 0 to use the compile-time default.
+*/
+static int getTempStore(const char *z){
+  if( z[0]>='0' && z[0]<='2' ){
+    return z[0] - '0';
+  }else if( sqlite3StrICmp(z, "file")==0 ){
+    return 1;
+  }else if( sqlite3StrICmp(z, "memory")==0 ){
+    return 2;
+  }else{
+    return 0;
+  }
+}
+#endif /* SQLITE_PAGER_PRAGMAS */
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+/*
+** Invalidate temp storage, either when the temp storage is changed
+** from default, or when 'file' and the temp_store_directory has changed
+*/
+static int invalidateTempStorage(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  if( db->aDb[1].pBt!=0 ){
+    if( !db->autoCommit
+     || sqlite3BtreeTxnState(db->aDb[1].pBt)!=SQLITE_TXN_NONE
+    ){
+      sqlite3ErrorMsg(pParse, "temporary storage cannot be changed "
+        "from within a transaction");
+      return SQLITE_ERROR;
+    }
+    sqlite3BtreeClose(db->aDb[1].pBt);
+    db->aDb[1].pBt = 0;
+    sqlite3ResetAllSchemasOfConnection(db);
+  }
+  return SQLITE_OK;
+}
+#endif /* SQLITE_PAGER_PRAGMAS */
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+/*
+** If the TEMP database is open, close it and mark the database schema
+** as needing reloading.  This must be done when using the SQLITE_TEMP_STORE
+** or DEFAULT_TEMP_STORE pragmas.
+*/
+static int changeTempStorage(Parse *pParse, const char *zStorageType){
+  int ts = getTempStore(zStorageType);
+  sqlite3 *db = pParse->db;
+  if( db->temp_store==ts ) return SQLITE_OK;
+  if( invalidateTempStorage( pParse ) != SQLITE_OK ){
+    return SQLITE_ERROR;
+  }
+  db->temp_store = (u8)ts;
+  return SQLITE_OK;
+}
+#endif /* SQLITE_PAGER_PRAGMAS */
+
+/*
+** Set result column names for a pragma.
+*/
+static void setPragmaResultColumnNames(
+  Vdbe *v,                     /* The query under construction */
+  const PragmaName *pPragma    /* The pragma */
+){
+  u8 n = pPragma->nPragCName;
+  sqlite3VdbeSetNumCols(v, n==0 ? 1 : n);
+  if( n==0 ){
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, pPragma->zName, SQLITE_STATIC);
+  }else{
+    int i, j;
+    for(i=0, j=pPragma->iPragCName; i<n; i++, j++){
+      sqlite3VdbeSetColName(v, i, COLNAME_NAME, pragCName[j], SQLITE_STATIC);
+    }
+  }
+}
+
+/*
+** Generate code to return a single integer value.
+*/
+static void returnSingleInt(Vdbe *v, i64 value){
+  sqlite3VdbeAddOp4Dup8(v, OP_Int64, 0, 1, 0, (const u8*)&value, P4_INT64);
+  sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+}
+
+/*
+** Generate code to return a single text value.
+*/
+static void returnSingleText(
+  Vdbe *v,                /* Prepared statement under construction */
+  const char *zValue      /* Value to be returned */
+){
+  if( zValue ){
+    sqlite3VdbeLoadString(v, 1, (const char*)zValue);
+    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+  }
+}
+
+
+/*
+** Set the safety_level and pager flags for pager iDb.  Or if iDb<0
+** set these values for all pagers.
+*/
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+static void setAllPagerFlags(sqlite3 *db){
+  if( db->autoCommit ){
+    Db *pDb = db->aDb;
+    int n = db->nDb;
+    assert( SQLITE_FullFSync==PAGER_FULLFSYNC );
+    assert( SQLITE_CkptFullFSync==PAGER_CKPT_FULLFSYNC );
+    assert( SQLITE_CacheSpill==PAGER_CACHESPILL );
+    assert( (PAGER_FULLFSYNC | PAGER_CKPT_FULLFSYNC | PAGER_CACHESPILL)
+             ==  PAGER_FLAGS_MASK );
+    assert( (pDb->safety_level & PAGER_SYNCHRONOUS_MASK)==pDb->safety_level );
+    while( (n--) > 0 ){
+      if( pDb->pBt ){
+        sqlite3BtreeSetPagerFlags(pDb->pBt,
+                 pDb->safety_level | (db->flags & PAGER_FLAGS_MASK) );
+      }
+      pDb++;
+    }
+  }
+}
+#else
+# define setAllPagerFlags(X)  /* no-op */
+#endif
+
+
+/*
+** Return a human-readable name for a constraint resolution action.
+*/
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+static const char *actionName(u8 action){
+  const char *zName;
+  switch( action ){
+    case OE_SetNull:  zName = "SET NULL";        break;
+    case OE_SetDflt:  zName = "SET DEFAULT";     break;
+    case OE_Cascade:  zName = "CASCADE";         break;
+    case OE_Restrict: zName = "RESTRICT";        break;
+    default:          zName = "NO ACTION";
+                      assert( action==OE_None ); break;
+  }
+  return zName;
+}
+#endif
+
+
+/*
+** Parameter eMode must be one of the PAGER_JOURNALMODE_XXX constants
+** defined in pager.h. This function returns the associated lowercase
+** journal-mode name.
+*/
+SQLITE_PRIVATE const char *sqlite3JournalModename(int eMode){
+  static char * const azModeName[] = {
+    "delete", "persist", "off", "truncate", "memory"
+#ifndef SQLITE_OMIT_WAL
+     , "wal"
+#endif
+  };
+  assert( PAGER_JOURNALMODE_DELETE==0 );
+  assert( PAGER_JOURNALMODE_PERSIST==1 );
+  assert( PAGER_JOURNALMODE_OFF==2 );
+  assert( PAGER_JOURNALMODE_TRUNCATE==3 );
+  assert( PAGER_JOURNALMODE_MEMORY==4 );
+  assert( PAGER_JOURNALMODE_WAL==5 );
+  assert( eMode>=0 && eMode<=ArraySize(azModeName) );
+
+  if( eMode==ArraySize(azModeName) ) return 0;
+  return azModeName[eMode];
+}
+
+/*
+** Locate a pragma in the aPragmaName[] array.
+*/
+static const PragmaName *pragmaLocate(const char *zName){
+  int upr, lwr, mid = 0, rc;
+  lwr = 0;
+  upr = ArraySize(aPragmaName)-1;
+  while( lwr<=upr ){
+    mid = (lwr+upr)/2;
+    rc = sqlite3_stricmp(zName, aPragmaName[mid].zName);
+    if( rc==0 ) break;
+    if( rc<0 ){
+      upr = mid - 1;
+    }else{
+      lwr = mid + 1;
+    }
+  }
+  return lwr>upr ? 0 : &aPragmaName[mid];
+}
+
+/*
+** Create zero or more entries in the output for the SQL functions
+** defined by FuncDef p.
+*/
+static void pragmaFunclistLine(
+  Vdbe *v,               /* The prepared statement being created */
+  FuncDef *p,            /* A particular function definition */
+  int isBuiltin,         /* True if this is a built-in function */
+  int showInternFuncs    /* True if showing internal functions */
+){
+  u32 mask =
+      SQLITE_DETERMINISTIC |
+      SQLITE_DIRECTONLY |
+      SQLITE_SUBTYPE |
+      SQLITE_INNOCUOUS |
+      SQLITE_FUNC_INTERNAL
+  ;
+  if( showInternFuncs ) mask = 0xffffffff;
+  for(; p; p=p->pNext){
+    const char *zType;
+    static const char *azEnc[] = { 0, "utf8", "utf16le", "utf16be" };
+
+    assert( SQLITE_FUNC_ENCMASK==0x3 );
+    assert( strcmp(azEnc[SQLITE_UTF8],"utf8")==0 );
+    assert( strcmp(azEnc[SQLITE_UTF16LE],"utf16le")==0 );
+    assert( strcmp(azEnc[SQLITE_UTF16BE],"utf16be")==0 );
+
+    if( p->xSFunc==0 ) continue;
+    if( (p->funcFlags & SQLITE_FUNC_INTERNAL)!=0
+     && showInternFuncs==0
+    ){
+      continue;
+    }
+    if( p->xValue!=0 ){
+      zType = "w";
+    }else if( p->xFinalize!=0 ){
+      zType = "a";
+    }else{
+      zType = "s";
+    }
+    sqlite3VdbeMultiLoad(v, 1, "sissii",
+       p->zName, isBuiltin,
+       zType, azEnc[p->funcFlags&SQLITE_FUNC_ENCMASK],
+       p->nArg,
+       (p->funcFlags & mask) ^ SQLITE_INNOCUOUS
+    );
+  }
+}
+
+
+/*
+** Helper subroutine for PRAGMA integrity_check:
+**
+** Generate code to output a single-column result row with a value of the
+** string held in register 3.  Decrement the result count in register 1
+** and halt if the maximum number of result rows have been issued.
+*/
+static int integrityCheckResultRow(Vdbe *v){
+  int addr;
+  sqlite3VdbeAddOp2(v, OP_ResultRow, 3, 1);
+  addr = sqlite3VdbeAddOp3(v, OP_IfPos, 1, sqlite3VdbeCurrentAddr(v)+2, 1);
+  VdbeCoverage(v);
+  sqlite3VdbeAddOp0(v, OP_Halt);
+  return addr;
+}
+
+/*
+** Process a pragma statement.
+**
+** Pragmas are of this form:
+**
+**      PRAGMA [schema.]id [= value]
+**
+** The identifier might also be a string.  The value is a string, and
+** identifier, or a number.  If minusFlag is true, then the value is
+** a number that was preceded by a minus sign.
+**
+** If the left side is "database.id" then pId1 is the database name
+** and pId2 is the id.  If the left side is just "id" then pId1 is the
+** id and pId2 is any empty string.
+*/
+SQLITE_PRIVATE void sqlite3Pragma(
+  Parse *pParse,
+  Token *pId1,        /* First part of [schema.]id field */
+  Token *pId2,        /* Second part of [schema.]id field, or NULL */
+  Token *pValue,      /* Token for <value>, or NULL */
+  int minusFlag       /* True if a '-' sign preceded <value> */
+){
+  char *zLeft = 0;       /* Nul-terminated UTF-8 string <id> */
+  char *zRight = 0;      /* Nul-terminated UTF-8 string <value>, or NULL */
+  const char *zDb = 0;   /* The database name */
+  Token *pId;            /* Pointer to <id> token */
+  char *aFcntl[4];       /* Argument to SQLITE_FCNTL_PRAGMA */
+  int iDb;               /* Database index for <database> */
+  int rc;                      /* return value form SQLITE_FCNTL_PRAGMA */
+  sqlite3 *db = pParse->db;    /* The database connection */
+  Db *pDb;                     /* The specific database being pragmaed */
+  Vdbe *v = sqlite3GetVdbe(pParse);  /* Prepared statement */
+  const PragmaName *pPragma;   /* The pragma */
+
+  if( v==0 ) return;
+  sqlite3VdbeRunOnlyOnce(v);
+  pParse->nMem = 2;
+
+  /* Interpret the [schema.] part of the pragma statement. iDb is the
+  ** index of the database this pragma is being applied to in db.aDb[]. */
+  iDb = sqlite3TwoPartName(pParse, pId1, pId2, &pId);
+  if( iDb<0 ) return;
+  pDb = &db->aDb[iDb];
+
+  /* If the temp database has been explicitly named as part of the
+  ** pragma, make sure it is open.
+  */
+  if( iDb==1 && sqlite3OpenTempDatabase(pParse) ){
+    return;
+  }
+
+  zLeft = sqlite3NameFromToken(db, pId);
+  if( !zLeft ) return;
+  if( minusFlag ){
+    zRight = sqlite3MPrintf(db, "-%T", pValue);
+  }else{
+    zRight = sqlite3NameFromToken(db, pValue);
+  }
+
+  assert( pId2 );
+  zDb = pId2->n>0 ? pDb->zDbSName : 0;
+  if( sqlite3AuthCheck(pParse, SQLITE_PRAGMA, zLeft, zRight, zDb) ){
+    goto pragma_out;
+  }
+
+  /* Send an SQLITE_FCNTL_PRAGMA file-control to the underlying VFS
+  ** connection.  If it returns SQLITE_OK, then assume that the VFS
+  ** handled the pragma and generate a no-op prepared statement.
+  **
+  ** IMPLEMENTATION-OF: R-12238-55120 Whenever a PRAGMA statement is parsed,
+  ** an SQLITE_FCNTL_PRAGMA file control is sent to the open sqlite3_file
+  ** object corresponding to the database file to which the pragma
+  ** statement refers.
+  **
+  ** IMPLEMENTATION-OF: R-29875-31678 The argument to the SQLITE_FCNTL_PRAGMA
+  ** file control is an array of pointers to strings (char**) in which the
+  ** second element of the array is the name of the pragma and the third
+  ** element is the argument to the pragma or NULL if the pragma has no
+  ** argument.
+  */
+  aFcntl[0] = 0;
+  aFcntl[1] = zLeft;
+  aFcntl[2] = zRight;
+  aFcntl[3] = 0;
+  db->busyHandler.nBusy = 0;
+  rc = sqlite3_file_control(db, zDb, SQLITE_FCNTL_PRAGMA, (void*)aFcntl);
+  if( rc==SQLITE_OK ){
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, aFcntl[0], SQLITE_TRANSIENT);
+    returnSingleText(v, aFcntl[0]);
+    sqlite3_free(aFcntl[0]);
+    goto pragma_out;
+  }
+  if( rc!=SQLITE_NOTFOUND ){
+    if( aFcntl[0] ){
+      sqlite3ErrorMsg(pParse, "%s", aFcntl[0]);
+      sqlite3_free(aFcntl[0]);
+    }
+    pParse->nErr++;
+    pParse->rc = rc;
+    goto pragma_out;
+  }
+
+  /* Locate the pragma in the lookup table */
+  pPragma = pragmaLocate(zLeft);
+  if( pPragma==0 ){
+    /* IMP: R-43042-22504 No error messages are generated if an
+    ** unknown pragma is issued. */
+    goto pragma_out;
+  }
+
+  /* Make sure the database schema is loaded if the pragma requires that */
+  if( (pPragma->mPragFlg & PragFlg_NeedSchema)!=0 ){
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+  }
+
+  /* Register the result column names for pragmas that return results */
+  if( (pPragma->mPragFlg & PragFlg_NoColumns)==0
+   && ((pPragma->mPragFlg & PragFlg_NoColumns1)==0 || zRight==0)
+  ){
+    setPragmaResultColumnNames(v, pPragma);
+  }
+
+  /* Jump to the appropriate pragma handler */
+  switch( pPragma->ePragTyp ){
+
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)
+  /*
+  **  PRAGMA [schema.]default_cache_size
+  **  PRAGMA [schema.]default_cache_size=N
+  **
+  ** The first form reports the current persistent setting for the
+  ** page cache size.  The value returned is the maximum number of
+  ** pages in the page cache.  The second form sets both the current
+  ** page cache size value and the persistent page cache size value
+  ** stored in the database file.
+  **
+  ** Older versions of SQLite would set the default cache size to a
+  ** negative number to indicate synchronous=OFF.  These days, synchronous
+  ** is always on by default regardless of the sign of the default cache
+  ** size.  But continue to take the absolute value of the default cache
+  ** size of historical compatibility.
+  */
+  case PragTyp_DEFAULT_CACHE_SIZE: {
+    static const int iLn = VDBE_OFFSET_LINENO(2);
+    static const VdbeOpList getCacheSize[] = {
+      { OP_Transaction, 0, 0,        0},                         /* 0 */
+      { OP_ReadCookie,  0, 1,        BTREE_DEFAULT_CACHE_SIZE},  /* 1 */
+      { OP_IfPos,       1, 8,        0},
+      { OP_Integer,     0, 2,        0},
+      { OP_Subtract,    1, 2,        1},
+      { OP_IfPos,       1, 8,        0},
+      { OP_Integer,     0, 1,        0},                         /* 6 */
+      { OP_Noop,        0, 0,        0},
+      { OP_ResultRow,   1, 1,        0},
+    };
+    VdbeOp *aOp;
+    sqlite3VdbeUsesBtree(v, iDb);
+    if( !zRight ){
+      pParse->nMem += 2;
+      sqlite3VdbeVerifyNoMallocRequired(v, ArraySize(getCacheSize));
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(getCacheSize), getCacheSize, iLn);
+      if( ONLY_IF_REALLOC_STRESS(aOp==0) ) break;
+      aOp[0].p1 = iDb;
+      aOp[1].p1 = iDb;
+      aOp[6].p1 = SQLITE_DEFAULT_CACHE_SIZE;
+    }else{
+      int size = sqlite3AbsInt32(sqlite3Atoi(zRight));
+      sqlite3BeginWriteOperation(pParse, 0, iDb);
+      sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_DEFAULT_CACHE_SIZE, size);
+      assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+      pDb->pSchema->cache_size = size;
+      sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
+    }
+    break;
+  }
+#endif /* !SQLITE_OMIT_PAGER_PRAGMAS && !SQLITE_OMIT_DEPRECATED */
+
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+  /*
+  **  PRAGMA [schema.]page_size
+  **  PRAGMA [schema.]page_size=N
+  **
+  ** The first form reports the current setting for the
+  ** database page size in bytes.  The second form sets the
+  ** database page size value.  The value can only be set if
+  ** the database has not yet been created.
+  */
+  case PragTyp_PAGE_SIZE: {
+    Btree *pBt = pDb->pBt;
+    assert( pBt!=0 );
+    if( !zRight ){
+      int size = ALWAYS(pBt) ? sqlite3BtreeGetPageSize(pBt) : 0;
+      returnSingleInt(v, size);
+    }else{
+      /* Malloc may fail when setting the page-size, as there is an internal
+      ** buffer that the pager module resizes using sqlite3_realloc().
+      */
+      db->nextPagesize = sqlite3Atoi(zRight);
+      if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize,0,0) ){
+        sqlite3OomFault(db);
+      }
+    }
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]secure_delete
+  **  PRAGMA [schema.]secure_delete=ON/OFF/FAST
+  **
+  ** The first form reports the current setting for the
+  ** secure_delete flag.  The second form changes the secure_delete
+  ** flag setting and reports the new value.
+  */
+  case PragTyp_SECURE_DELETE: {
+    Btree *pBt = pDb->pBt;
+    int b = -1;
+    assert( pBt!=0 );
+    if( zRight ){
+      if( sqlite3_stricmp(zRight, "fast")==0 ){
+        b = 2;
+      }else{
+        b = sqlite3GetBoolean(zRight, 0);
+      }
+    }
+    if( pId2->n==0 && b>=0 ){
+      int ii;
+      for(ii=0; ii<db->nDb; ii++){
+        sqlite3BtreeSecureDelete(db->aDb[ii].pBt, b);
+      }
+    }
+    b = sqlite3BtreeSecureDelete(pBt, b);
+    returnSingleInt(v, b);
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]max_page_count
+  **  PRAGMA [schema.]max_page_count=N
+  **
+  ** The first form reports the current setting for the
+  ** maximum number of pages in the database file.  The
+  ** second form attempts to change this setting.  Both
+  ** forms return the current setting.
+  **
+  ** The absolute value of N is used.  This is undocumented and might
+  ** change.  The only purpose is to provide an easy way to test
+  ** the sqlite3AbsInt32() function.
+  **
+  **  PRAGMA [schema.]page_count
+  **
+  ** Return the number of pages in the specified database.
+  */
+  case PragTyp_PAGE_COUNT: {
+    int iReg;
+    i64 x = 0;
+    sqlite3CodeVerifySchema(pParse, iDb);
+    iReg = ++pParse->nMem;
+    if( sqlite3Tolower(zLeft[0])=='p' ){
+      sqlite3VdbeAddOp2(v, OP_Pagecount, iDb, iReg);
+    }else{
+      if( zRight && sqlite3DecOrHexToI64(zRight,&x)==0 ){
+        if( x<0 ) x = 0;
+        else if( x>0xfffffffe ) x = 0xfffffffe;
+      }else{
+        x = 0;
+      }
+      sqlite3VdbeAddOp3(v, OP_MaxPgcnt, iDb, iReg, (int)x);
+    }
+    sqlite3VdbeAddOp2(v, OP_ResultRow, iReg, 1);
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]locking_mode
+  **  PRAGMA [schema.]locking_mode = (normal|exclusive)
+  */
+  case PragTyp_LOCKING_MODE: {
+    const char *zRet = "normal";
+    int eMode = getLockingMode(zRight);
+
+    if( pId2->n==0 && eMode==PAGER_LOCKINGMODE_QUERY ){
+      /* Simple "PRAGMA locking_mode;" statement. This is a query for
+      ** the current default locking mode (which may be different to
+      ** the locking-mode of the main database).
+      */
+      eMode = db->dfltLockMode;
+    }else{
+      Pager *pPager;
+      if( pId2->n==0 ){
+        /* This indicates that no database name was specified as part
+        ** of the PRAGMA command. In this case the locking-mode must be
+        ** set on all attached databases, as well as the main db file.
+        **
+        ** Also, the sqlite3.dfltLockMode variable is set so that
+        ** any subsequently attached databases also use the specified
+        ** locking mode.
+        */
+        int ii;
+        assert(pDb==&db->aDb[0]);
+        for(ii=2; ii<db->nDb; ii++){
+          pPager = sqlite3BtreePager(db->aDb[ii].pBt);
+          sqlite3PagerLockingMode(pPager, eMode);
+        }
+        db->dfltLockMode = (u8)eMode;
+      }
+      pPager = sqlite3BtreePager(pDb->pBt);
+      eMode = sqlite3PagerLockingMode(pPager, eMode);
+    }
+
+    assert( eMode==PAGER_LOCKINGMODE_NORMAL
+            || eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
+    if( eMode==PAGER_LOCKINGMODE_EXCLUSIVE ){
+      zRet = "exclusive";
+    }
+    returnSingleText(v, zRet);
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]journal_mode
+  **  PRAGMA [schema.]journal_mode =
+  **                      (delete|persist|off|truncate|memory|wal|off)
+  */
+  case PragTyp_JOURNAL_MODE: {
+    int eMode;        /* One of the PAGER_JOURNALMODE_XXX symbols */
+    int ii;           /* Loop counter */
+
+    if( zRight==0 ){
+      /* If there is no "=MODE" part of the pragma, do a query for the
+      ** current mode */
+      eMode = PAGER_JOURNALMODE_QUERY;
+    }else{
+      const char *zMode;
+      int n = sqlite3Strlen30(zRight);
+      for(eMode=0; (zMode = sqlite3JournalModename(eMode))!=0; eMode++){
+        if( sqlite3StrNICmp(zRight, zMode, n)==0 ) break;
+      }
+      if( !zMode ){
+        /* If the "=MODE" part does not match any known journal mode,
+        ** then do a query */
+        eMode = PAGER_JOURNALMODE_QUERY;
+      }
+      if( eMode==PAGER_JOURNALMODE_OFF && (db->flags & SQLITE_Defensive)!=0 ){
+        /* Do not allow journal-mode "OFF" in defensive since the database
+        ** can become corrupted using ordinary SQL when the journal is off */
+        eMode = PAGER_JOURNALMODE_QUERY;
+      }
+    }
+    if( eMode==PAGER_JOURNALMODE_QUERY && pId2->n==0 ){
+      /* Convert "PRAGMA journal_mode" into "PRAGMA main.journal_mode" */
+      iDb = 0;
+      pId2->n = 1;
+    }
+    for(ii=db->nDb-1; ii>=0; ii--){
+      if( db->aDb[ii].pBt && (ii==iDb || pId2->n==0) ){
+        sqlite3VdbeUsesBtree(v, ii);
+        sqlite3VdbeAddOp3(v, OP_JournalMode, ii, 1, eMode);
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]journal_size_limit
+  **  PRAGMA [schema.]journal_size_limit=N
+  **
+  ** Get or set the size limit on rollback journal files.
+  */
+  case PragTyp_JOURNAL_SIZE_LIMIT: {
+    Pager *pPager = sqlite3BtreePager(pDb->pBt);
+    i64 iLimit = -2;
+    if( zRight ){
+      sqlite3DecOrHexToI64(zRight, &iLimit);
+      if( iLimit<-1 ) iLimit = -1;
+    }
+    iLimit = sqlite3PagerJournalSizeLimit(pPager, iLimit);
+    returnSingleInt(v, iLimit);
+    break;
+  }
+
+#endif /* SQLITE_OMIT_PAGER_PRAGMAS */
+
+  /*
+  **  PRAGMA [schema.]auto_vacuum
+  **  PRAGMA [schema.]auto_vacuum=N
+  **
+  ** Get or set the value of the database 'auto-vacuum' parameter.
+  ** The value is one of:  0 NONE 1 FULL 2 INCREMENTAL
+  */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  case PragTyp_AUTO_VACUUM: {
+    Btree *pBt = pDb->pBt;
+    assert( pBt!=0 );
+    if( !zRight ){
+      returnSingleInt(v, sqlite3BtreeGetAutoVacuum(pBt));
+    }else{
+      int eAuto = getAutoVacuum(zRight);
+      assert( eAuto>=0 && eAuto<=2 );
+      db->nextAutovac = (u8)eAuto;
+      /* Call SetAutoVacuum() to set initialize the internal auto and
+      ** incr-vacuum flags. This is required in case this connection
+      ** creates the database file. It is important that it is created
+      ** as an auto-vacuum capable db.
+      */
+      rc = sqlite3BtreeSetAutoVacuum(pBt, eAuto);
+      if( rc==SQLITE_OK && (eAuto==1 || eAuto==2) ){
+        /* When setting the auto_vacuum mode to either "full" or
+        ** "incremental", write the value of meta[6] in the database
+        ** file. Before writing to meta[6], check that meta[3] indicates
+        ** that this really is an auto-vacuum capable database.
+        */
+        static const int iLn = VDBE_OFFSET_LINENO(2);
+        static const VdbeOpList setMeta6[] = {
+          { OP_Transaction,    0,         1,                 0},    /* 0 */
+          { OP_ReadCookie,     0,         1,         BTREE_LARGEST_ROOT_PAGE},
+          { OP_If,             1,         0,                 0},    /* 2 */
+          { OP_Halt,           SQLITE_OK, OE_Abort,          0},    /* 3 */
+          { OP_SetCookie,      0,         BTREE_INCR_VACUUM, 0},    /* 4 */
+        };
+        VdbeOp *aOp;
+        int iAddr = sqlite3VdbeCurrentAddr(v);
+        sqlite3VdbeVerifyNoMallocRequired(v, ArraySize(setMeta6));
+        aOp = sqlite3VdbeAddOpList(v, ArraySize(setMeta6), setMeta6, iLn);
+        if( ONLY_IF_REALLOC_STRESS(aOp==0) ) break;
+        aOp[0].p1 = iDb;
+        aOp[1].p1 = iDb;
+        aOp[2].p2 = iAddr+4;
+        aOp[4].p1 = iDb;
+        aOp[4].p3 = eAuto - 1;
+        sqlite3VdbeUsesBtree(v, iDb);
+      }
+    }
+    break;
+  }
+#endif
+
+  /*
+  **  PRAGMA [schema.]incremental_vacuum(N)
+  **
+  ** Do N steps of incremental vacuuming on a database.
+  */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  case PragTyp_INCREMENTAL_VACUUM: {
+    int iLimit = 0, addr;
+    if( zRight==0 || !sqlite3GetInt32(zRight, &iLimit) || iLimit<=0 ){
+      iLimit = 0x7fffffff;
+    }
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    sqlite3VdbeAddOp2(v, OP_Integer, iLimit, 1);
+    addr = sqlite3VdbeAddOp1(v, OP_IncrVacuum, iDb); VdbeCoverage(v);
+    sqlite3VdbeAddOp1(v, OP_ResultRow, 1);
+    sqlite3VdbeAddOp2(v, OP_AddImm, 1, -1);
+    sqlite3VdbeAddOp2(v, OP_IfPos, 1, addr); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr);
+    break;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+  /*
+  **  PRAGMA [schema.]cache_size
+  **  PRAGMA [schema.]cache_size=N
+  **
+  ** The first form reports the current local setting for the
+  ** page cache size. The second form sets the local
+  ** page cache size value.  If N is positive then that is the
+  ** number of pages in the cache.  If N is negative, then the
+  ** number of pages is adjusted so that the cache uses -N kibibytes
+  ** of memory.
+  */
+  case PragTyp_CACHE_SIZE: {
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( !zRight ){
+      returnSingleInt(v, pDb->pSchema->cache_size);
+    }else{
+      int size = sqlite3Atoi(zRight);
+      pDb->pSchema->cache_size = size;
+      sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
+    }
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]cache_spill
+  **  PRAGMA cache_spill=BOOLEAN
+  **  PRAGMA [schema.]cache_spill=N
+  **
+  ** The first form reports the current local setting for the
+  ** page cache spill size. The second form turns cache spill on
+  ** or off.  When turning cache spill on, the size is set to the
+  ** current cache_size.  The third form sets a spill size that
+  ** may be different form the cache size.
+  ** If N is positive then that is the
+  ** number of pages in the cache.  If N is negative, then the
+  ** number of pages is adjusted so that the cache uses -N kibibytes
+  ** of memory.
+  **
+  ** If the number of cache_spill pages is less then the number of
+  ** cache_size pages, no spilling occurs until the page count exceeds
+  ** the number of cache_size pages.
+  **
+  ** The cache_spill=BOOLEAN setting applies to all attached schemas,
+  ** not just the schema specified.
+  */
+  case PragTyp_CACHE_SPILL: {
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( !zRight ){
+      returnSingleInt(v,
+         (db->flags & SQLITE_CacheSpill)==0 ? 0 :
+            sqlite3BtreeSetSpillSize(pDb->pBt,0));
+    }else{
+      int size = 1;
+      if( sqlite3GetInt32(zRight, &size) ){
+        sqlite3BtreeSetSpillSize(pDb->pBt, size);
+      }
+      if( sqlite3GetBoolean(zRight, size!=0) ){
+        db->flags |= SQLITE_CacheSpill;
+      }else{
+        db->flags &= ~(u64)SQLITE_CacheSpill;
+      }
+      setAllPagerFlags(db);
+    }
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]mmap_size(N)
+  **
+  ** Used to set mapping size limit. The mapping size limit is
+  ** used to limit the aggregate size of all memory mapped regions of the
+  ** database file. If this parameter is set to zero, then memory mapping
+  ** is not used at all.  If N is negative, then the default memory map
+  ** limit determined by sqlite3_config(SQLITE_CONFIG_MMAP_SIZE) is set.
+  ** The parameter N is measured in bytes.
+  **
+  ** This value is advisory.  The underlying VFS is free to memory map
+  ** as little or as much as it wants.  Except, if N is set to 0 then the
+  ** upper layers will never invoke the xFetch interfaces to the VFS.
+  */
+  case PragTyp_MMAP_SIZE: {
+    sqlite3_int64 sz;
+#if SQLITE_MAX_MMAP_SIZE>0
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( zRight ){
+      int ii;
+      sqlite3DecOrHexToI64(zRight, &sz);
+      if( sz<0 ) sz = sqlite3GlobalConfig.szMmap;
+      if( pId2->n==0 ) db->szMmap = sz;
+      for(ii=db->nDb-1; ii>=0; ii--){
+        if( db->aDb[ii].pBt && (ii==iDb || pId2->n==0) ){
+          sqlite3BtreeSetMmapLimit(db->aDb[ii].pBt, sz);
+        }
+      }
+    }
+    sz = -1;
+    rc = sqlite3_file_control(db, zDb, SQLITE_FCNTL_MMAP_SIZE, &sz);
+#else
+    sz = 0;
+    rc = SQLITE_OK;
+#endif
+    if( rc==SQLITE_OK ){
+      returnSingleInt(v, sz);
+    }else if( rc!=SQLITE_NOTFOUND ){
+      pParse->nErr++;
+      pParse->rc = rc;
+    }
+    break;
+  }
+
+  /*
+  **   PRAGMA temp_store
+  **   PRAGMA temp_store = "default"|"memory"|"file"
+  **
+  ** Return or set the local value of the temp_store flag.  Changing
+  ** the local value does not make changes to the disk file and the default
+  ** value will be restored the next time the database is opened.
+  **
+  ** Note that it is possible for the library compile-time options to
+  ** override this setting
+  */
+  case PragTyp_TEMP_STORE: {
+    if( !zRight ){
+      returnSingleInt(v, db->temp_store);
+    }else{
+      changeTempStorage(pParse, zRight);
+    }
+    break;
+  }
+
+  /*
+  **   PRAGMA temp_store_directory
+  **   PRAGMA temp_store_directory = ""|"directory_name"
+  **
+  ** Return or set the local value of the temp_store_directory flag.  Changing
+  ** the value sets a specific directory to be used for temporary files.
+  ** Setting to a null string reverts to the default temporary directory search.
+  ** If temporary directory is changed, then invalidateTempStorage.
+  **
+  */
+  case PragTyp_TEMP_STORE_DIRECTORY: {
+    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+    if( !zRight ){
+      returnSingleText(v, sqlite3_temp_directory);
+    }else{
+#ifndef SQLITE_OMIT_WSD
+      if( zRight[0] ){
+        int res;
+        rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
+        if( rc!=SQLITE_OK || res==0 ){
+          sqlite3ErrorMsg(pParse, "not a writable directory");
+          sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+          goto pragma_out;
+        }
+      }
+      if( SQLITE_TEMP_STORE==0
+       || (SQLITE_TEMP_STORE==1 && db->temp_store<=1)
+       || (SQLITE_TEMP_STORE==2 && db->temp_store==1)
+      ){
+        invalidateTempStorage(pParse);
+      }
+      sqlite3_free(sqlite3_temp_directory);
+      if( zRight[0] ){
+        sqlite3_temp_directory = sqlite3_mprintf("%s", zRight);
+      }else{
+        sqlite3_temp_directory = 0;
+      }
+#endif /* SQLITE_OMIT_WSD */
+    }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+    break;
+  }
+
+#if SQLITE_OS_WIN
+  /*
+  **   PRAGMA data_store_directory
+  **   PRAGMA data_store_directory = ""|"directory_name"
+  **
+  ** Return or set the local value of the data_store_directory flag.  Changing
+  ** the value sets a specific directory to be used for database files that
+  ** were specified with a relative pathname.  Setting to a null string reverts
+  ** to the default database directory, which for database files specified with
+  ** a relative path will probably be based on the current directory for the
+  ** process.  Database file specified with an absolute path are not impacted
+  ** by this setting, regardless of its value.
+  **
+  */
+  case PragTyp_DATA_STORE_DIRECTORY: {
+    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+    if( !zRight ){
+      returnSingleText(v, sqlite3_data_directory);
+    }else{
+#ifndef SQLITE_OMIT_WSD
+      if( zRight[0] ){
+        int res;
+        rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
+        if( rc!=SQLITE_OK || res==0 ){
+          sqlite3ErrorMsg(pParse, "not a writable directory");
+          sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+          goto pragma_out;
+        }
+      }
+      sqlite3_free(sqlite3_data_directory);
+      if( zRight[0] ){
+        sqlite3_data_directory = sqlite3_mprintf("%s", zRight);
+      }else{
+        sqlite3_data_directory = 0;
+      }
+#endif /* SQLITE_OMIT_WSD */
+    }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+    break;
+  }
+#endif
+
+#if SQLITE_ENABLE_LOCKING_STYLE
+  /*
+  **   PRAGMA [schema.]lock_proxy_file
+  **   PRAGMA [schema.]lock_proxy_file = ":auto:"|"lock_file_path"
+  **
+  ** Return or set the value of the lock_proxy_file flag.  Changing
+  ** the value sets a specific file to be used for database access locks.
+  **
+  */
+  case PragTyp_LOCK_PROXY_FILE: {
+    if( !zRight ){
+      Pager *pPager = sqlite3BtreePager(pDb->pBt);
+      char *proxy_file_path = NULL;
+      sqlite3_file *pFile = sqlite3PagerFile(pPager);
+      sqlite3OsFileControlHint(pFile, SQLITE_GET_LOCKPROXYFILE,
+                           &proxy_file_path);
+      returnSingleText(v, proxy_file_path);
+    }else{
+      Pager *pPager = sqlite3BtreePager(pDb->pBt);
+      sqlite3_file *pFile = sqlite3PagerFile(pPager);
+      int res;
+      if( zRight[0] ){
+        res=sqlite3OsFileControl(pFile, SQLITE_SET_LOCKPROXYFILE,
+                                     zRight);
+      } else {
+        res=sqlite3OsFileControl(pFile, SQLITE_SET_LOCKPROXYFILE,
+                                     NULL);
+      }
+      if( res!=SQLITE_OK ){
+        sqlite3ErrorMsg(pParse, "failed to set lock proxy file");
+        goto pragma_out;
+      }
+    }
+    break;
+  }
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+  /*
+  **   PRAGMA [schema.]synchronous
+  **   PRAGMA [schema.]synchronous=OFF|ON|NORMAL|FULL|EXTRA
+  **
+  ** Return or set the local value of the synchronous flag.  Changing
+  ** the local value does not make changes to the disk file and the
+  ** default value will be restored the next time the database is
+  ** opened.
+  */
+  case PragTyp_SYNCHRONOUS: {
+    if( !zRight ){
+      returnSingleInt(v, pDb->safety_level-1);
+    }else{
+      if( !db->autoCommit ){
+        sqlite3ErrorMsg(pParse,
+            "Safety level may not be changed inside a transaction");
+      }else if( iDb!=1 ){
+        int iLevel = (getSafetyLevel(zRight,0,1)+1) & PAGER_SYNCHRONOUS_MASK;
+        if( iLevel==0 ) iLevel = 1;
+        pDb->safety_level = iLevel;
+        pDb->bSyncSet = 1;
+        setAllPagerFlags(db);
+      }
+    }
+    break;
+  }
+#endif /* SQLITE_OMIT_PAGER_PRAGMAS */
+
+#ifndef SQLITE_OMIT_FLAG_PRAGMAS
+  case PragTyp_FLAG: {
+    if( zRight==0 ){
+      setPragmaResultColumnNames(v, pPragma);
+      returnSingleInt(v, (db->flags & pPragma->iArg)!=0 );
+    }else{
+      u64 mask = pPragma->iArg;    /* Mask of bits to set or clear. */
+      if( db->autoCommit==0 ){
+        /* Foreign key support may not be enabled or disabled while not
+        ** in auto-commit mode.  */
+        mask &= ~(SQLITE_ForeignKeys);
+      }
+
+      if( sqlite3GetBoolean(zRight, 0) ){
+        if( (mask & SQLITE_WriteSchema)==0
+         || (db->flags & SQLITE_Defensive)==0
+        ){
+          db->flags |= mask;
+        }
+      }else{
+        db->flags &= ~mask;
+        if( mask==SQLITE_DeferFKs ) db->nDeferredImmCons = 0;
+        if( (mask & SQLITE_WriteSchema)!=0
+         && sqlite3_stricmp(zRight, "reset")==0
+        ){
+          /* IMP: R-60817-01178 If the argument is "RESET" then schema
+          ** writing is disabled (as with "PRAGMA writable_schema=OFF") and,
+          ** in addition, the schema is reloaded. */
+          sqlite3ResetAllSchemasOfConnection(db);
+        }
+      }
+
+      /* Many of the flag-pragmas modify the code generated by the SQL
+      ** compiler (eg. count_changes). So add an opcode to expire all
+      ** compiled SQL statements after modifying a pragma value.
+      */
+      sqlite3VdbeAddOp0(v, OP_Expire);
+      setAllPagerFlags(db);
+    }
+    break;
+  }
+#endif /* SQLITE_OMIT_FLAG_PRAGMAS */
+
+#ifndef SQLITE_OMIT_SCHEMA_PRAGMAS
+  /*
+  **   PRAGMA table_info(<table>)
+  **
+  ** Return a single row for each column of the named table. The columns of
+  ** the returned data set are:
+  **
+  ** cid:        Column id (numbered from left to right, starting at 0)
+  ** name:       Column name
+  ** type:       Column declaration type.
+  ** notnull:    True if 'NOT NULL' is part of column declaration
+  ** dflt_value: The default value for the column, if any.
+  ** pk:         Non-zero for PK fields.
+  */
+  case PragTyp_TABLE_INFO: if( zRight ){
+    Table *pTab;
+    sqlite3CodeVerifyNamedSchema(pParse, zDb);
+    pTab = sqlite3LocateTable(pParse, LOCATE_NOERR, zRight, zDb);
+    if( pTab ){
+      int i, k;
+      int nHidden = 0;
+      Column *pCol;
+      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+      pParse->nMem = 7;
+      sqlite3ViewGetColumnNames(pParse, pTab);
+      for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
+        int isHidden = 0;
+        const Expr *pColExpr;
+        if( pCol->colFlags & COLFLAG_NOINSERT ){
+          if( pPragma->iArg==0 ){
+            nHidden++;
+            continue;
+          }
+          if( pCol->colFlags & COLFLAG_VIRTUAL ){
+            isHidden = 2;  /* GENERATED ALWAYS AS ... VIRTUAL */
+          }else if( pCol->colFlags & COLFLAG_STORED ){
+            isHidden = 3;  /* GENERATED ALWAYS AS ... STORED */
+          }else{ assert( pCol->colFlags & COLFLAG_HIDDEN );
+            isHidden = 1;  /* HIDDEN */
+          }
+        }
+        if( (pCol->colFlags & COLFLAG_PRIMKEY)==0 ){
+          k = 0;
+        }else if( pPk==0 ){
+          k = 1;
+        }else{
+          for(k=1; k<=pTab->nCol && pPk->aiColumn[k-1]!=i; k++){}
+        }
+        pColExpr = sqlite3ColumnExpr(pTab,pCol);
+        assert( pColExpr==0 || pColExpr->op==TK_SPAN || isHidden>=2 );
+        assert( pColExpr==0 || !ExprHasProperty(pColExpr, EP_IntValue)
+                  || isHidden>=2 );
+        sqlite3VdbeMultiLoad(v, 1, pPragma->iArg ? "issisii" : "issisi",
+               i-nHidden,
+               pCol->zCnName,
+               sqlite3ColumnType(pCol,""),
+               pCol->notNull ? 1 : 0,
+               (isHidden>=2 || pColExpr==0) ? 0 : pColExpr->u.zToken,
+               k,
+               isHidden);
+      }
+    }
+  }
+  break;
+
+  /*
+  **   PRAGMA table_list
+  **
+  ** Return a single row for each table, virtual table, or view in the
+  ** entire schema.
+  **
+  ** schema:     Name of attached database hold this table
+  ** name:       Name of the table itself
+  ** type:       "table", "view", "virtual", "shadow"
+  ** ncol:       Number of columns
+  ** wr:         True for a WITHOUT ROWID table
+  ** strict:     True for a STRICT table
+  */
+  case PragTyp_TABLE_LIST: {
+    int ii;
+    pParse->nMem = 6;
+    sqlite3CodeVerifyNamedSchema(pParse, zDb);
+    for(ii=0; ii<db->nDb; ii++){
+      HashElem *k;
+      Hash *pHash;
+      int initNCol;
+      if( zDb && sqlite3_stricmp(zDb, db->aDb[ii].zDbSName)!=0 ) continue;
+
+      /* Ensure that the Table.nCol field is initialized for all views
+      ** and virtual tables.  Each time we initialize a Table.nCol value
+      ** for a table, that can potentially disrupt the hash table, so restart
+      ** the initialization scan.
+      */
+      pHash = &db->aDb[ii].pSchema->tblHash;
+      initNCol = sqliteHashCount(pHash);
+      while( initNCol-- ){
+        for(k=sqliteHashFirst(pHash); 1; k=sqliteHashNext(k) ){
+          Table *pTab;
+          if( k==0 ){ initNCol = 0; break; }
+          pTab = sqliteHashData(k);
+          if( pTab->nCol==0 ){
+            char *zSql = sqlite3MPrintf(db, "SELECT*FROM\"%w\"", pTab->zName);
+            if( zSql ){
+              sqlite3_stmt *pDummy = 0;
+              (void)sqlite3_prepare_v3(db, zSql, -1, SQLITE_PREPARE_DONT_LOG,
+                                       &pDummy, 0);
+              (void)sqlite3_finalize(pDummy);
+              sqlite3DbFree(db, zSql);
+            }
+            if( db->mallocFailed ){
+              sqlite3ErrorMsg(db->pParse, "out of memory");
+              db->pParse->rc = SQLITE_NOMEM_BKPT;
+            }
+            pHash = &db->aDb[ii].pSchema->tblHash;
+            break;
+          }
+        }
+      }
+
+      for(k=sqliteHashFirst(pHash); k; k=sqliteHashNext(k) ){
+        Table *pTab = sqliteHashData(k);
+        const char *zType;
+        if( zRight && sqlite3_stricmp(zRight, pTab->zName)!=0 ) continue;
+        if( IsView(pTab) ){
+          zType = "view";
+        }else if( IsVirtual(pTab) ){
+          zType = "virtual";
+        }else if( pTab->tabFlags & TF_Shadow ){
+          zType = "shadow";
+        }else{
+          zType = "table";
+        }
+        sqlite3VdbeMultiLoad(v, 1, "sssiii",
+           db->aDb[ii].zDbSName,
+           sqlite3PreferredTableName(pTab->zName),
+           zType,
+           pTab->nCol,
+           (pTab->tabFlags & TF_WithoutRowid)!=0,
+           (pTab->tabFlags & TF_Strict)!=0
+        );
+      }
+    }
+  }
+  break;
+
+#ifdef SQLITE_DEBUG
+  case PragTyp_STATS: {
+    Index *pIdx;
+    HashElem *i;
+    pParse->nMem = 5;
+    sqlite3CodeVerifySchema(pParse, iDb);
+    for(i=sqliteHashFirst(&pDb->pSchema->tblHash); i; i=sqliteHashNext(i)){
+      Table *pTab = sqliteHashData(i);
+      sqlite3VdbeMultiLoad(v, 1, "ssiii",
+           sqlite3PreferredTableName(pTab->zName),
+           0,
+           pTab->szTabRow,
+           pTab->nRowLogEst,
+           pTab->tabFlags);
+      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+        sqlite3VdbeMultiLoad(v, 2, "siiiX",
+           pIdx->zName,
+           pIdx->szIdxRow,
+           pIdx->aiRowLogEst[0],
+           pIdx->hasStat1);
+        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 5);
+      }
+    }
+  }
+  break;
+#endif
+
+  case PragTyp_INDEX_INFO: if( zRight ){
+    Index *pIdx;
+    Table *pTab;
+    pIdx = sqlite3FindIndex(db, zRight, zDb);
+    if( pIdx==0 ){
+      /* If there is no index named zRight, check to see if there is a
+      ** WITHOUT ROWID table named zRight, and if there is, show the
+      ** structure of the PRIMARY KEY index for that table. */
+      pTab = sqlite3LocateTable(pParse, LOCATE_NOERR, zRight, zDb);
+      if( pTab && !HasRowid(pTab) ){
+        pIdx = sqlite3PrimaryKeyIndex(pTab);
+      }
+    }
+    if( pIdx ){
+      int iIdxDb = sqlite3SchemaToIndex(db, pIdx->pSchema);
+      int i;
+      int mx;
+      if( pPragma->iArg ){
+        /* PRAGMA index_xinfo (newer version with more rows and columns) */
+        mx = pIdx->nColumn;
+        pParse->nMem = 6;
+      }else{
+        /* PRAGMA index_info (legacy version) */
+        mx = pIdx->nKeyCol;
+        pParse->nMem = 3;
+      }
+      pTab = pIdx->pTable;
+      sqlite3CodeVerifySchema(pParse, iIdxDb);
+      assert( pParse->nMem<=pPragma->nPragCName );
+      for(i=0; i<mx; i++){
+        i16 cnum = pIdx->aiColumn[i];
+        sqlite3VdbeMultiLoad(v, 1, "iisX", i, cnum,
+                             cnum<0 ? 0 : pTab->aCol[cnum].zCnName);
+        if( pPragma->iArg ){
+          sqlite3VdbeMultiLoad(v, 4, "isiX",
+            pIdx->aSortOrder[i],
+            pIdx->azColl[i],
+            i<pIdx->nKeyCol);
+        }
+        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, pParse->nMem);
+      }
+    }
+  }
+  break;
+
+  case PragTyp_INDEX_LIST: if( zRight ){
+    Index *pIdx;
+    Table *pTab;
+    int i;
+    pTab = sqlite3FindTable(db, zRight, zDb);
+    if( pTab ){
+      int iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      pParse->nMem = 5;
+      sqlite3CodeVerifySchema(pParse, iTabDb);
+      for(pIdx=pTab->pIndex, i=0; pIdx; pIdx=pIdx->pNext, i++){
+        const char *azOrigin[] = { "c", "u", "pk" };
+        sqlite3VdbeMultiLoad(v, 1, "isisi",
+           i,
+           pIdx->zName,
+           IsUniqueIndex(pIdx),
+           azOrigin[pIdx->idxType],
+           pIdx->pPartIdxWhere!=0);
+      }
+    }
+  }
+  break;
+
+  case PragTyp_DATABASE_LIST: {
+    int i;
+    pParse->nMem = 3;
+    for(i=0; i<db->nDb; i++){
+      if( db->aDb[i].pBt==0 ) continue;
+      assert( db->aDb[i].zDbSName!=0 );
+      sqlite3VdbeMultiLoad(v, 1, "iss",
+         i,
+         db->aDb[i].zDbSName,
+         sqlite3BtreeGetFilename(db->aDb[i].pBt));
+    }
+  }
+  break;
+
+  case PragTyp_COLLATION_LIST: {
+    int i = 0;
+    HashElem *p;
+    pParse->nMem = 2;
+    for(p=sqliteHashFirst(&db->aCollSeq); p; p=sqliteHashNext(p)){
+      CollSeq *pColl = (CollSeq *)sqliteHashData(p);
+      sqlite3VdbeMultiLoad(v, 1, "is", i++, pColl->zName);
+    }
+  }
+  break;
+
+#ifndef SQLITE_OMIT_INTROSPECTION_PRAGMAS
+  case PragTyp_FUNCTION_LIST: {
+    int i;
+    HashElem *j;
+    FuncDef *p;
+    int showInternFunc = (db->mDbFlags & DBFLAG_InternalFunc)!=0;
+    pParse->nMem = 6;
+    for(i=0; i<SQLITE_FUNC_HASH_SZ; i++){
+      for(p=sqlite3BuiltinFunctions.a[i]; p; p=p->u.pHash ){
+        assert( p->funcFlags & SQLITE_FUNC_BUILTIN );
+        pragmaFunclistLine(v, p, 1, showInternFunc);
+      }
+    }
+    for(j=sqliteHashFirst(&db->aFunc); j; j=sqliteHashNext(j)){
+      p = (FuncDef*)sqliteHashData(j);
+      assert( (p->funcFlags & SQLITE_FUNC_BUILTIN)==0 );
+      pragmaFunclistLine(v, p, 0, showInternFunc);
+    }
+  }
+  break;
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  case PragTyp_MODULE_LIST: {
+    HashElem *j;
+    pParse->nMem = 1;
+    for(j=sqliteHashFirst(&db->aModule); j; j=sqliteHashNext(j)){
+      Module *pMod = (Module*)sqliteHashData(j);
+      sqlite3VdbeMultiLoad(v, 1, "s", pMod->zName);
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+  case PragTyp_PRAGMA_LIST: {
+    int i;
+    for(i=0; i<ArraySize(aPragmaName); i++){
+      sqlite3VdbeMultiLoad(v, 1, "s", aPragmaName[i].zName);
+    }
+  }
+  break;
+#endif /* SQLITE_INTROSPECTION_PRAGMAS */
+
+#endif /* SQLITE_OMIT_SCHEMA_PRAGMAS */
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  case PragTyp_FOREIGN_KEY_LIST: if( zRight ){
+    FKey *pFK;
+    Table *pTab;
+    pTab = sqlite3FindTable(db, zRight, zDb);
+    if( pTab && IsOrdinaryTable(pTab) ){
+      pFK = pTab->u.tab.pFKey;
+      if( pFK ){
+        int iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+        int i = 0;
+        pParse->nMem = 8;
+        sqlite3CodeVerifySchema(pParse, iTabDb);
+        while(pFK){
+          int j;
+          for(j=0; j<pFK->nCol; j++){
+            sqlite3VdbeMultiLoad(v, 1, "iissssss",
+                   i,
+                   j,
+                   pFK->zTo,
+                   pTab->aCol[pFK->aCol[j].iFrom].zCnName,
+                   pFK->aCol[j].zCol,
+                   actionName(pFK->aAction[1]),  /* ON UPDATE */
+                   actionName(pFK->aAction[0]),  /* ON DELETE */
+                   "NONE");
+          }
+          ++i;
+          pFK = pFK->pNextFrom;
+        }
+      }
+    }
+  }
+  break;
+#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+#ifndef SQLITE_OMIT_TRIGGER
+  case PragTyp_FOREIGN_KEY_CHECK: {
+    FKey *pFK;             /* A foreign key constraint */
+    Table *pTab;           /* Child table contain "REFERENCES" keyword */
+    Table *pParent;        /* Parent table that child points to */
+    Index *pIdx;           /* Index in the parent table */
+    int i;                 /* Loop counter:  Foreign key number for pTab */
+    int j;                 /* Loop counter:  Field of the foreign key */
+    HashElem *k;           /* Loop counter:  Next table in schema */
+    int x;                 /* result variable */
+    int regResult;         /* 3 registers to hold a result row */
+    int regRow;            /* Registers to hold a row from pTab */
+    int addrTop;           /* Top of a loop checking foreign keys */
+    int addrOk;            /* Jump here if the key is OK */
+    int *aiCols;           /* child to parent column mapping */
+
+    regResult = pParse->nMem+1;
+    pParse->nMem += 4;
+    regRow = ++pParse->nMem;
+    k = sqliteHashFirst(&db->aDb[iDb].pSchema->tblHash);
+    while( k ){
+      if( zRight ){
+        pTab = sqlite3LocateTable(pParse, 0, zRight, zDb);
+        k = 0;
+      }else{
+        pTab = (Table*)sqliteHashData(k);
+        k = sqliteHashNext(k);
+      }
+      if( pTab==0 || !IsOrdinaryTable(pTab) || pTab->u.tab.pFKey==0 ) continue;
+      iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      zDb = db->aDb[iDb].zDbSName;
+      sqlite3CodeVerifySchema(pParse, iDb);
+      sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+      sqlite3TouchRegister(pParse, pTab->nCol+regRow);
+      sqlite3OpenTable(pParse, 0, iDb, pTab, OP_OpenRead);
+      sqlite3VdbeLoadString(v, regResult, pTab->zName);
+      assert( IsOrdinaryTable(pTab) );
+      for(i=1, pFK=pTab->u.tab.pFKey; pFK; i++, pFK=pFK->pNextFrom){
+        pParent = sqlite3FindTable(db, pFK->zTo, zDb);
+        if( pParent==0 ) continue;
+        pIdx = 0;
+        sqlite3TableLock(pParse, iDb, pParent->tnum, 0, pParent->zName);
+        x = sqlite3FkLocateIndex(pParse, pParent, pFK, &pIdx, 0);
+        if( x==0 ){
+          if( pIdx==0 ){
+            sqlite3OpenTable(pParse, i, iDb, pParent, OP_OpenRead);
+          }else{
+            sqlite3VdbeAddOp3(v, OP_OpenRead, i, pIdx->tnum, iDb);
+            sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+          }
+        }else{
+          k = 0;
+          break;
+        }
+      }
+      assert( pParse->nErr>0 || pFK==0 );
+      if( pFK ) break;
+      if( pParse->nTab<i ) pParse->nTab = i;
+      addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, 0); VdbeCoverage(v);
+      assert( IsOrdinaryTable(pTab) );
+      for(i=1, pFK=pTab->u.tab.pFKey; pFK; i++, pFK=pFK->pNextFrom){
+        pParent = sqlite3FindTable(db, pFK->zTo, zDb);
+        pIdx = 0;
+        aiCols = 0;
+        if( pParent ){
+          x = sqlite3FkLocateIndex(pParse, pParent, pFK, &pIdx, &aiCols);
+          assert( x==0 || db->mallocFailed );
+        }
+        addrOk = sqlite3VdbeMakeLabel(pParse);
+
+        /* Generate code to read the child key values into registers
+        ** regRow..regRow+n. If any of the child key values are NULL, this
+        ** row cannot cause an FK violation. Jump directly to addrOk in
+        ** this case. */
+        sqlite3TouchRegister(pParse, regRow + pFK->nCol);
+        for(j=0; j<pFK->nCol; j++){
+          int iCol = aiCols ? aiCols[j] : pFK->aCol[j].iFrom;
+          sqlite3ExprCodeGetColumnOfTable(v, pTab, 0, iCol, regRow+j);
+          sqlite3VdbeAddOp2(v, OP_IsNull, regRow+j, addrOk); VdbeCoverage(v);
+        }
+
+        /* Generate code to query the parent index for a matching parent
+        ** key. If a match is found, jump to addrOk. */
+        if( pIdx ){
+          sqlite3VdbeAddOp4(v, OP_Affinity, regRow, pFK->nCol, 0,
+              sqlite3IndexAffinityStr(db,pIdx), pFK->nCol);
+          sqlite3VdbeAddOp4Int(v, OP_Found, i, addrOk, regRow, pFK->nCol);
+          VdbeCoverage(v);
+        }else if( pParent ){
+          int jmp = sqlite3VdbeCurrentAddr(v)+2;
+          sqlite3VdbeAddOp3(v, OP_SeekRowid, i, jmp, regRow); VdbeCoverage(v);
+          sqlite3VdbeGoto(v, addrOk);
+          assert( pFK->nCol==1 || db->mallocFailed );
+        }
+
+        /* Generate code to report an FK violation to the caller. */
+        if( HasRowid(pTab) ){
+          sqlite3VdbeAddOp2(v, OP_Rowid, 0, regResult+1);
+        }else{
+          sqlite3VdbeAddOp2(v, OP_Null, 0, regResult+1);
+        }
+        sqlite3VdbeMultiLoad(v, regResult+2, "siX", pFK->zTo, i-1);
+        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, 4);
+        sqlite3VdbeResolveLabel(v, addrOk);
+        sqlite3DbFree(db, aiCols);
+      }
+      sqlite3VdbeAddOp2(v, OP_Next, 0, addrTop+1); VdbeCoverage(v);
+      sqlite3VdbeJumpHere(v, addrTop);
+    }
+  }
+  break;
+#endif /* !defined(SQLITE_OMIT_TRIGGER) */
+#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */
+
+#ifndef SQLITE_OMIT_CASE_SENSITIVE_LIKE_PRAGMA
+  /* Reinstall the LIKE and GLOB functions.  The variant of LIKE
+  ** used will be case sensitive or not depending on the RHS.
+  */
+  case PragTyp_CASE_SENSITIVE_LIKE: {
+    if( zRight ){
+      sqlite3RegisterLikeFunctions(db, sqlite3GetBoolean(zRight, 0));
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_CASE_SENSITIVE_LIKE_PRAGMA */
+
+#ifndef SQLITE_INTEGRITY_CHECK_ERROR_MAX
+# define SQLITE_INTEGRITY_CHECK_ERROR_MAX 100
+#endif
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+  /*    PRAGMA integrity_check
+  **    PRAGMA integrity_check(N)
+  **    PRAGMA quick_check
+  **    PRAGMA quick_check(N)
+  **
+  ** Verify the integrity of the database.
+  **
+  ** The "quick_check" is reduced version of
+  ** integrity_check designed to detect most database corruption
+  ** without the overhead of cross-checking indexes.  Quick_check
+  ** is linear time whereas integrity_check is O(NlogN).
+  **
+  ** The maximum number of errors is 100 by default.  A different default
+  ** can be specified using a numeric parameter N.
+  **
+  ** Or, the parameter N can be the name of a table.  In that case, only
+  ** the one table named is verified.  The freelist is only verified if
+  ** the named table is "sqlite_schema" (or one of its aliases).
+  **
+  ** All schemas are checked by default.  To check just a single
+  ** schema, use the form:
+  **
+  **      PRAGMA schema.integrity_check;
+  */
+  case PragTyp_INTEGRITY_CHECK: {
+    int i, j, addr, mxErr;
+    Table *pObjTab = 0;     /* Check only this one table, if not NULL */
+
+    int isQuick = (sqlite3Tolower(zLeft[0])=='q');
+
+    /* If the PRAGMA command was of the form "PRAGMA <db>.integrity_check",
+    ** then iDb is set to the index of the database identified by <db>.
+    ** In this case, the integrity of database iDb only is verified by
+    ** the VDBE created below.
+    **
+    ** Otherwise, if the command was simply "PRAGMA integrity_check" (or
+    ** "PRAGMA quick_check"), then iDb is set to 0. In this case, set iDb
+    ** to -1 here, to indicate that the VDBE should verify the integrity
+    ** of all attached databases.  */
+    assert( iDb>=0 );
+    assert( iDb==0 || pId2->z );
+    if( pId2->z==0 ) iDb = -1;
+
+    /* Initialize the VDBE program */
+    pParse->nMem = 6;
+
+    /* Set the maximum error count */
+    mxErr = SQLITE_INTEGRITY_CHECK_ERROR_MAX;
+    if( zRight ){
+      if( sqlite3GetInt32(pValue->z, &mxErr) ){
+        if( mxErr<=0 ){
+          mxErr = SQLITE_INTEGRITY_CHECK_ERROR_MAX;
+        }
+      }else{
+        pObjTab = sqlite3LocateTable(pParse, 0, zRight,
+                      iDb>=0 ? db->aDb[iDb].zDbSName : 0);
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_Integer, mxErr-1, 1); /* reg[1] holds errors left */
+
+    /* Do an integrity check on each database file */
+    for(i=0; i<db->nDb; i++){
+      HashElem *x;     /* For looping over tables in the schema */
+      Hash *pTbls;     /* Set of all tables in the schema */
+      int *aRoot;      /* Array of root page numbers of all btrees */
+      int cnt = 0;     /* Number of entries in aRoot[] */
+
+      if( OMIT_TEMPDB && i==1 ) continue;
+      if( iDb>=0 && i!=iDb ) continue;
+
+      sqlite3CodeVerifySchema(pParse, i);
+      pParse->okConstFactor = 0;  /* tag-20230327-1 */
+
+      /* Do an integrity check of the B-Tree
+      **
+      ** Begin by finding the root pages numbers
+      ** for all tables and indices in the database.
+      */
+      assert( sqlite3SchemaMutexHeld(db, i, 0) );
+      pTbls = &db->aDb[i].pSchema->tblHash;
+      for(cnt=0, x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);  /* Current table */
+        Index *pIdx;                      /* An index on pTab */
+        int nIdx;                         /* Number of indexes on pTab */
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( HasRowid(pTab) ) cnt++;
+        for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){ cnt++; }
+      }
+      if( cnt==0 ) continue;
+      if( pObjTab ) cnt++;
+      aRoot = sqlite3DbMallocRawNN(db, sizeof(int)*(cnt+1));
+      if( aRoot==0 ) break;
+      cnt = 0;
+      if( pObjTab ) aRoot[++cnt] = 0;
+      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);
+        Index *pIdx;
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( HasRowid(pTab) ) aRoot[++cnt] = pTab->tnum;
+        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+          aRoot[++cnt] = pIdx->tnum;
+        }
+      }
+      aRoot[0] = cnt;
+
+      /* Make sure sufficient number of registers have been allocated */
+      sqlite3TouchRegister(pParse, 8+cnt);
+      sqlite3VdbeAddOp3(v, OP_Null, 0, 8, 8+cnt);
+      sqlite3ClearTempRegCache(pParse);
+
+      /* Do the b-tree integrity checks */
+      sqlite3VdbeAddOp4(v, OP_IntegrityCk, 1, cnt, 8, (char*)aRoot,P4_INTARRAY);
+      sqlite3VdbeChangeP5(v, (u16)i);
+      addr = sqlite3VdbeAddOp1(v, OP_IsNull, 2); VdbeCoverage(v);
+      sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
+         sqlite3MPrintf(db, "*** in database %s ***\n", db->aDb[i].zDbSName),
+         P4_DYNAMIC);
+      sqlite3VdbeAddOp3(v, OP_Concat, 2, 3, 3);
+      integrityCheckResultRow(v);
+      sqlite3VdbeJumpHere(v, addr);
+
+      /* Check that the indexes all have the right number of rows */
+      cnt = pObjTab ? 1 : 0;
+      sqlite3VdbeLoadString(v, 2, "wrong # of entries in index ");
+      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        int iTab = 0;
+        Table *pTab = sqliteHashData(x);
+        Index *pIdx;
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( HasRowid(pTab) ){
+          iTab = cnt++;
+        }else{
+          iTab = cnt;
+          for(pIdx=pTab->pIndex; ALWAYS(pIdx); pIdx=pIdx->pNext){
+            if( IsPrimaryKeyIndex(pIdx) ) break;
+            iTab++;
+          }
+        }
+        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+          if( pIdx->pPartIdxWhere==0 ){
+            addr = sqlite3VdbeAddOp3(v, OP_Eq, 8+cnt, 0, 8+iTab);
+            VdbeCoverageNeverNull(v);
+            sqlite3VdbeLoadString(v, 4, pIdx->zName);
+            sqlite3VdbeAddOp3(v, OP_Concat, 4, 2, 3);
+            integrityCheckResultRow(v);
+            sqlite3VdbeJumpHere(v, addr);
+          }
+          cnt++;
+        }
+      }
+
+      /* Make sure all the indices are constructed correctly.
+      */
+      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);
+        Index *pIdx, *pPk;
+        Index *pPrior = 0;      /* Previous index */
+        int loopTop;
+        int iDataCur, iIdxCur;
+        int r1 = -1;
+        int bStrict;            /* True for a STRICT table */
+        int r2;                 /* Previous key for WITHOUT ROWID tables */
+        int mxCol;              /* Maximum non-virtual column number */
+
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( !IsOrdinaryTable(pTab) ) continue;
+        if( isQuick || HasRowid(pTab) ){
+          pPk = 0;
+          r2 = 0;
+        }else{
+          pPk = sqlite3PrimaryKeyIndex(pTab);
+          r2 = sqlite3GetTempRange(pParse, pPk->nKeyCol);
+          sqlite3VdbeAddOp3(v, OP_Null, 1, r2, r2+pPk->nKeyCol-1);
+        }
+        sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenRead, 0,
+                                   1, 0, &iDataCur, &iIdxCur);
+        /* reg[7] counts the number of entries in the table.
+        ** reg[8+i] counts the number of entries in the i-th index
+        */
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, 7);
+        for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
+          sqlite3VdbeAddOp2(v, OP_Integer, 0, 8+j); /* index entries counter */
+        }
+        assert( pParse->nMem>=8+j );
+        assert( sqlite3NoTempsInRange(pParse,1,7+j) );
+        sqlite3VdbeAddOp2(v, OP_Rewind, iDataCur, 0); VdbeCoverage(v);
+        loopTop = sqlite3VdbeAddOp2(v, OP_AddImm, 7, 1);
+
+        /* Fetch the right-most column from the table.  This will cause
+        ** the entire record header to be parsed and sanity checked.  It
+        ** will also prepopulate the cursor column cache that is used
+        ** by the OP_IsType code, so it is a required step.
+        */
+        assert( !IsVirtual(pTab) );
+        if( HasRowid(pTab) ){
+          mxCol = -1;
+          for(j=0; j<pTab->nCol; j++){
+            if( (pTab->aCol[j].colFlags & COLFLAG_VIRTUAL)==0 ) mxCol++;
+          }
+          if( mxCol==pTab->iPKey ) mxCol--;
+        }else{
+          /* COLFLAG_VIRTUAL columns are not included in the WITHOUT ROWID
+          ** PK index column-count, so there is no need to account for them
+          ** in this case. */
+          mxCol = sqlite3PrimaryKeyIndex(pTab)->nColumn-1;
+        }
+        if( mxCol>=0 ){
+          sqlite3VdbeAddOp3(v, OP_Column, iDataCur, mxCol, 3);
+          sqlite3VdbeTypeofColumn(v, 3);
+        }
+
+        if( !isQuick ){
+          if( pPk ){
+            /* Verify WITHOUT ROWID keys are in ascending order */
+            int a1;
+            char *zErr;
+            a1 = sqlite3VdbeAddOp4Int(v, OP_IdxGT, iDataCur, 0,r2,pPk->nKeyCol);
+            VdbeCoverage(v);
+            sqlite3VdbeAddOp1(v, OP_IsNull, r2); VdbeCoverage(v);
+            zErr = sqlite3MPrintf(db,
+                   "row not in PRIMARY KEY order for %s",
+                    pTab->zName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+            integrityCheckResultRow(v);
+            sqlite3VdbeJumpHere(v, a1);
+            sqlite3VdbeJumpHere(v, a1+1);
+            for(j=0; j<pPk->nKeyCol; j++){
+              sqlite3ExprCodeLoadIndexColumn(pParse, pPk, iDataCur, j, r2+j);
+            }
+          }
+        }
+        /* Verify datatypes for all columns:
+        **
+        **   (1) NOT NULL columns may not contain a NULL
+        **   (2) Datatype must be exact for non-ANY columns in STRICT tables
+        **   (3) Datatype for TEXT columns in non-STRICT tables must be
+        **       NULL, TEXT, or BLOB.
+        **   (4) Datatype for numeric columns in non-STRICT tables must not
+        **       be a TEXT value that can be losslessly converted to numeric.
+        */
+        bStrict = (pTab->tabFlags & TF_Strict)!=0;
+        for(j=0; j<pTab->nCol; j++){
+          char *zErr;
+          Column *pCol = pTab->aCol + j;  /* The column to be checked */
+          int labelError;               /* Jump here to report an error */
+          int labelOk;                  /* Jump here if all looks ok */
+          int p1, p3, p4;               /* Operands to the OP_IsType opcode */
+          int doTypeCheck;              /* Check datatypes (besides NOT NULL) */
+
+          if( j==pTab->iPKey ) continue;
+          if( bStrict ){
+            doTypeCheck = pCol->eCType>COLTYPE_ANY;
+          }else{
+            doTypeCheck = pCol->affinity>SQLITE_AFF_BLOB;
+          }
+          if( pCol->notNull==0 && !doTypeCheck ) continue;
+
+          /* Compute the operands that will be needed for OP_IsType */
+          p4 = SQLITE_NULL;
+          if( pCol->colFlags & COLFLAG_VIRTUAL ){
+            sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, j, 3);
+            p1 = -1;
+            p3 = 3;
+          }else{
+            if( pCol->iDflt ){
+              sqlite3_value *pDfltValue = 0;
+              sqlite3ValueFromExpr(db, sqlite3ColumnExpr(pTab,pCol), ENC(db),
+                                   pCol->affinity, &pDfltValue);
+              if( pDfltValue ){
+                p4 = sqlite3_value_type(pDfltValue);
+                sqlite3ValueFree(pDfltValue);
+              }
+            }
+            p1 = iDataCur;
+            if( !HasRowid(pTab) ){
+              testcase( j!=sqlite3TableColumnToStorage(pTab, j) );
+              p3 = sqlite3TableColumnToIndex(sqlite3PrimaryKeyIndex(pTab), j);
+            }else{
+              p3 = sqlite3TableColumnToStorage(pTab,j);
+              testcase( p3!=j);
+            }
+          }
+
+          labelError = sqlite3VdbeMakeLabel(pParse);
+          labelOk = sqlite3VdbeMakeLabel(pParse);
+          if( pCol->notNull ){
+            /* (1) NOT NULL columns may not contain a NULL */
+            int jmp3;
+            int jmp2 = sqlite3VdbeAddOp4Int(v, OP_IsType, p1, labelOk, p3, p4);
+            VdbeCoverage(v);
+            if( p1<0 ){
+              sqlite3VdbeChangeP5(v, 0x0f); /* INT, REAL, TEXT, or BLOB */
+              jmp3 = jmp2;
+            }else{
+              sqlite3VdbeChangeP5(v, 0x0d); /* INT, TEXT, or BLOB */
+              /* OP_IsType does not detect NaN values in the database file
+              ** which should be treated as a NULL.  So if the header type
+              ** is REAL, we have to load the actual data using OP_Column
+              ** to reliably determine if the value is a NULL. */
+              sqlite3VdbeAddOp3(v, OP_Column, p1, p3, 3);
+              sqlite3ColumnDefault(v, pTab, j, 3);
+              jmp3 = sqlite3VdbeAddOp2(v, OP_NotNull, 3, labelOk);
+              VdbeCoverage(v);
+            }
+            zErr = sqlite3MPrintf(db, "NULL value in %s.%s", pTab->zName,
+                                pCol->zCnName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+            if( doTypeCheck ){
+              sqlite3VdbeGoto(v, labelError);
+              sqlite3VdbeJumpHere(v, jmp2);
+              sqlite3VdbeJumpHere(v, jmp3);
+            }else{
+              /* VDBE byte code will fall thru */
+            }
+          }
+          if( bStrict && doTypeCheck ){
+            /* (2) Datatype must be exact for non-ANY columns in STRICT tables*/
+            static unsigned char aStdTypeMask[] = {
+               0x1f,    /* ANY */
+               0x18,    /* BLOB */
+               0x11,    /* INT */
+               0x11,    /* INTEGER */
+               0x13,    /* REAL */
+               0x14     /* TEXT */
+            };
+            sqlite3VdbeAddOp4Int(v, OP_IsType, p1, labelOk, p3, p4);
+            assert( pCol->eCType>=1 && pCol->eCType<=sizeof(aStdTypeMask) );
+            sqlite3VdbeChangeP5(v, aStdTypeMask[pCol->eCType-1]);
+            VdbeCoverage(v);
+            zErr = sqlite3MPrintf(db, "non-%s value in %s.%s",
+                                  sqlite3StdType[pCol->eCType-1],
+                                  pTab->zName, pTab->aCol[j].zCnName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+          }else if( !bStrict && pCol->affinity==SQLITE_AFF_TEXT ){
+            /* (3) Datatype for TEXT columns in non-STRICT tables must be
+            **     NULL, TEXT, or BLOB. */
+            sqlite3VdbeAddOp4Int(v, OP_IsType, p1, labelOk, p3, p4);
+            sqlite3VdbeChangeP5(v, 0x1c); /* NULL, TEXT, or BLOB */
+            VdbeCoverage(v);
+            zErr = sqlite3MPrintf(db, "NUMERIC value in %s.%s",
+                                  pTab->zName, pTab->aCol[j].zCnName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+          }else if( !bStrict && pCol->affinity>=SQLITE_AFF_NUMERIC ){
+            /* (4) Datatype for numeric columns in non-STRICT tables must not
+            **     be a TEXT value that can be converted to numeric. */
+            sqlite3VdbeAddOp4Int(v, OP_IsType, p1, labelOk, p3, p4);
+            sqlite3VdbeChangeP5(v, 0x1b); /* NULL, INT, FLOAT, or BLOB */
+            VdbeCoverage(v);
+            if( p1>=0 ){
+              sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, j, 3);
+            }
+            sqlite3VdbeAddOp4(v, OP_Affinity, 3, 1, 0, "C", P4_STATIC);
+            sqlite3VdbeAddOp4Int(v, OP_IsType, -1, labelOk, 3, p4);
+            sqlite3VdbeChangeP5(v, 0x1c); /* NULL, TEXT, or BLOB */
+            VdbeCoverage(v);
+            zErr = sqlite3MPrintf(db, "TEXT value in %s.%s",
+                                  pTab->zName, pTab->aCol[j].zCnName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+          }
+          sqlite3VdbeResolveLabel(v, labelError);
+          integrityCheckResultRow(v);
+          sqlite3VdbeResolveLabel(v, labelOk);
+        }
+        /* Verify CHECK constraints */
+        if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
+          ExprList *pCheck = sqlite3ExprListDup(db, pTab->pCheck, 0);
+          if( db->mallocFailed==0 ){
+            int addrCkFault = sqlite3VdbeMakeLabel(pParse);
+            int addrCkOk = sqlite3VdbeMakeLabel(pParse);
+            char *zErr;
+            int k;
+            pParse->iSelfTab = iDataCur + 1;
+            for(k=pCheck->nExpr-1; k>0; k--){
+              sqlite3ExprIfFalse(pParse, pCheck->a[k].pExpr, addrCkFault, 0);
+            }
+            sqlite3ExprIfTrue(pParse, pCheck->a[0].pExpr, addrCkOk,
+                SQLITE_JUMPIFNULL);
+            sqlite3VdbeResolveLabel(v, addrCkFault);
+            pParse->iSelfTab = 0;
+            zErr = sqlite3MPrintf(db, "CHECK constraint failed in %s",
+                pTab->zName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+            integrityCheckResultRow(v);
+            sqlite3VdbeResolveLabel(v, addrCkOk);
+          }
+          sqlite3ExprListDelete(db, pCheck);
+        }
+        if( !isQuick ){ /* Omit the remaining tests for quick_check */
+          /* Validate index entries for the current row */
+          for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
+            int jmp2, jmp3, jmp4, jmp5, label6;
+            int kk;
+            int ckUniq = sqlite3VdbeMakeLabel(pParse);
+            if( pPk==pIdx ) continue;
+            r1 = sqlite3GenerateIndexKey(pParse, pIdx, iDataCur, 0, 0, &jmp3,
+                                         pPrior, r1);
+            pPrior = pIdx;
+            sqlite3VdbeAddOp2(v, OP_AddImm, 8+j, 1);/* increment entry count */
+            /* Verify that an index entry exists for the current table row */
+            jmp2 = sqlite3VdbeAddOp4Int(v, OP_Found, iIdxCur+j, ckUniq, r1,
+                                        pIdx->nColumn); VdbeCoverage(v);
+            sqlite3VdbeLoadString(v, 3, "row ");
+            sqlite3VdbeAddOp3(v, OP_Concat, 7, 3, 3);
+            sqlite3VdbeLoadString(v, 4, " missing from index ");
+            sqlite3VdbeAddOp3(v, OP_Concat, 4, 3, 3);
+            jmp5 = sqlite3VdbeLoadString(v, 4, pIdx->zName);
+            sqlite3VdbeAddOp3(v, OP_Concat, 4, 3, 3);
+            jmp4 = integrityCheckResultRow(v);
+            sqlite3VdbeJumpHere(v, jmp2);
+
+            /* The OP_IdxRowid opcode is an optimized version of OP_Column
+            ** that extracts the rowid off the end of the index record.
+            ** But it only works correctly if index record does not have
+            ** any extra bytes at the end.  Verify that this is the case. */
+            if( HasRowid(pTab) ){
+              int jmp7;
+              sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur+j, 3);
+              jmp7 = sqlite3VdbeAddOp3(v, OP_Eq, 3, 0, r1+pIdx->nColumn-1);
+              VdbeCoverageNeverNull(v);
+              sqlite3VdbeLoadString(v, 3,
+                 "rowid not at end-of-record for row ");
+              sqlite3VdbeAddOp3(v, OP_Concat, 7, 3, 3);
+              sqlite3VdbeLoadString(v, 4, " of index ");
+              sqlite3VdbeGoto(v, jmp5-1);
+              sqlite3VdbeJumpHere(v, jmp7);
+            }
+
+            /* Any indexed columns with non-BINARY collations must still hold
+            ** the exact same text value as the table. */
+            label6 = 0;
+            for(kk=0; kk<pIdx->nKeyCol; kk++){
+              if( pIdx->azColl[kk]==sqlite3StrBINARY ) continue;
+              if( label6==0 ) label6 = sqlite3VdbeMakeLabel(pParse);
+              sqlite3VdbeAddOp3(v, OP_Column, iIdxCur+j, kk, 3);
+              sqlite3VdbeAddOp3(v, OP_Ne, 3, label6, r1+kk); VdbeCoverage(v);
+            }
+            if( label6 ){
+              int jmp6 = sqlite3VdbeAddOp0(v, OP_Goto);
+              sqlite3VdbeResolveLabel(v, label6);
+              sqlite3VdbeLoadString(v, 3, "row ");
+              sqlite3VdbeAddOp3(v, OP_Concat, 7, 3, 3);
+              sqlite3VdbeLoadString(v, 4, " values differ from index ");
+              sqlite3VdbeGoto(v, jmp5-1);
+              sqlite3VdbeJumpHere(v, jmp6);
+            }
+
+            /* For UNIQUE indexes, verify that only one entry exists with the
+            ** current key.  The entry is unique if (1) any column is NULL
+            ** or (2) the next entry has a different key */
+            if( IsUniqueIndex(pIdx) ){
+              int uniqOk = sqlite3VdbeMakeLabel(pParse);
+              int jmp6;
+              for(kk=0; kk<pIdx->nKeyCol; kk++){
+                int iCol = pIdx->aiColumn[kk];
+                assert( iCol!=XN_ROWID && iCol<pTab->nCol );
+                if( iCol>=0 && pTab->aCol[iCol].notNull ) continue;
+                sqlite3VdbeAddOp2(v, OP_IsNull, r1+kk, uniqOk);
+                VdbeCoverage(v);
+              }
+              jmp6 = sqlite3VdbeAddOp1(v, OP_Next, iIdxCur+j); VdbeCoverage(v);
+              sqlite3VdbeGoto(v, uniqOk);
+              sqlite3VdbeJumpHere(v, jmp6);
+              sqlite3VdbeAddOp4Int(v, OP_IdxGT, iIdxCur+j, uniqOk, r1,
+                                   pIdx->nKeyCol); VdbeCoverage(v);
+              sqlite3VdbeLoadString(v, 3, "non-unique entry in index ");
+              sqlite3VdbeGoto(v, jmp5);
+              sqlite3VdbeResolveLabel(v, uniqOk);
+            }
+            sqlite3VdbeJumpHere(v, jmp4);
+            sqlite3ResolvePartIdxLabel(pParse, jmp3);
+          }
+        }
+        sqlite3VdbeAddOp2(v, OP_Next, iDataCur, loopTop); VdbeCoverage(v);
+        sqlite3VdbeJumpHere(v, loopTop-1);
+        if( pPk ){
+          assert( !isQuick );
+          sqlite3ReleaseTempRange(pParse, r2, pPk->nKeyCol);
+        }
+      }
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      /* Second pass to invoke the xIntegrity method on all virtual
+      ** tables.
+      */
+      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);
+        sqlite3_vtab *pVTab;
+        int a1;
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( IsOrdinaryTable(pTab) ) continue;
+        if( !IsVirtual(pTab) ) continue;
+        if( pTab->nCol<=0 ){
+          const char *zMod = pTab->u.vtab.azArg[0];
+          if( sqlite3HashFind(&db->aModule, zMod)==0 ) continue;
+        }
+        sqlite3ViewGetColumnNames(pParse, pTab);
+        if( pTab->u.vtab.p==0 ) continue;
+        pVTab = pTab->u.vtab.p->pVtab;
+        if( NEVER(pVTab==0) ) continue;
+        if( NEVER(pVTab->pModule==0) ) continue;
+        if( pVTab->pModule->iVersion<4 ) continue;
+        if( pVTab->pModule->xIntegrity==0 ) continue;
+        sqlite3VdbeAddOp3(v, OP_VCheck, i, 3, isQuick);
+        pTab->nTabRef++;
+        sqlite3VdbeAppendP4(v, pTab, P4_TABLEREF);
+        a1 = sqlite3VdbeAddOp1(v, OP_IsNull, 3); VdbeCoverage(v);
+        integrityCheckResultRow(v);
+        sqlite3VdbeJumpHere(v, a1);
+        continue;
+      }
+#endif
+    }
+    {
+      static const int iLn = VDBE_OFFSET_LINENO(2);
+      static const VdbeOpList endCode[] = {
+        { OP_AddImm,      1, 0,        0},    /* 0 */
+        { OP_IfNotZero,   1, 4,        0},    /* 1 */
+        { OP_String8,     0, 3,        0},    /* 2 */
+        { OP_ResultRow,   3, 1,        0},    /* 3 */
+        { OP_Halt,        0, 0,        0},    /* 4 */
+        { OP_String8,     0, 3,        0},    /* 5 */
+        { OP_Goto,        0, 3,        0},    /* 6 */
+      };
+      VdbeOp *aOp;
+
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(endCode), endCode, iLn);
+      if( aOp ){
+        aOp[0].p2 = 1-mxErr;
+        aOp[2].p4type = P4_STATIC;
+        aOp[2].p4.z = "ok";
+        aOp[5].p4type = P4_STATIC;
+        aOp[5].p4.z = (char*)sqlite3ErrStr(SQLITE_CORRUPT);
+      }
+      sqlite3VdbeChangeP3(v, 0, sqlite3VdbeCurrentAddr(v)-2);
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_UTF16
+  /*
+  **   PRAGMA encoding
+  **   PRAGMA encoding = "utf-8"|"utf-16"|"utf-16le"|"utf-16be"
+  **
+  ** In its first form, this pragma returns the encoding of the main
+  ** database. If the database is not initialized, it is initialized now.
+  **
+  ** The second form of this pragma is a no-op if the main database file
+  ** has not already been initialized. In this case it sets the default
+  ** encoding that will be used for the main database file if a new file
+  ** is created. If an existing main database file is opened, then the
+  ** default text encoding for the existing database is used.
+  **
+  ** In all cases new databases created using the ATTACH command are
+  ** created to use the same default text encoding as the main database. If
+  ** the main database has not been initialized and/or created when ATTACH
+  ** is executed, this is done before the ATTACH operation.
+  **
+  ** In the second form this pragma sets the text encoding to be used in
+  ** new database files created using this database handle. It is only
+  ** useful if invoked immediately after the main database i
+  */
+  case PragTyp_ENCODING: {
+    static const struct EncName {
+      char *zName;
+      u8 enc;
+    } encnames[] = {
+      { "UTF8",     SQLITE_UTF8        },
+      { "UTF-8",    SQLITE_UTF8        },  /* Must be element [1] */
+      { "UTF-16le", SQLITE_UTF16LE     },  /* Must be element [2] */
+      { "UTF-16be", SQLITE_UTF16BE     },  /* Must be element [3] */
+      { "UTF16le",  SQLITE_UTF16LE     },
+      { "UTF16be",  SQLITE_UTF16BE     },
+      { "UTF-16",   0                  }, /* SQLITE_UTF16NATIVE */
+      { "UTF16",    0                  }, /* SQLITE_UTF16NATIVE */
+      { 0, 0 }
+    };
+    const struct EncName *pEnc;
+    if( !zRight ){    /* "PRAGMA encoding" */
+      if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+      assert( encnames[SQLITE_UTF8].enc==SQLITE_UTF8 );
+      assert( encnames[SQLITE_UTF16LE].enc==SQLITE_UTF16LE );
+      assert( encnames[SQLITE_UTF16BE].enc==SQLITE_UTF16BE );
+      returnSingleText(v, encnames[ENC(pParse->db)].zName);
+    }else{                        /* "PRAGMA encoding = XXX" */
+      /* Only change the value of sqlite.enc if the database handle is not
+      ** initialized. If the main database exists, the new sqlite.enc value
+      ** will be overwritten when the schema is next loaded. If it does not
+      ** already exists, it will be created to use the new encoding value.
+      */
+      if( (db->mDbFlags & DBFLAG_EncodingFixed)==0 ){
+        for(pEnc=&encnames[0]; pEnc->zName; pEnc++){
+          if( 0==sqlite3StrICmp(zRight, pEnc->zName) ){
+            u8 enc = pEnc->enc ? pEnc->enc : SQLITE_UTF16NATIVE;
+            SCHEMA_ENC(db) = enc;
+            sqlite3SetTextEncoding(db, enc);
+            break;
+          }
+        }
+        if( !pEnc->zName ){
+          sqlite3ErrorMsg(pParse, "unsupported encoding: %s", zRight);
+        }
+      }
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_UTF16 */
+
+#ifndef SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS
+  /*
+  **   PRAGMA [schema.]schema_version
+  **   PRAGMA [schema.]schema_version = <integer>
+  **
+  **   PRAGMA [schema.]user_version
+  **   PRAGMA [schema.]user_version = <integer>
+  **
+  **   PRAGMA [schema.]freelist_count
+  **
+  **   PRAGMA [schema.]data_version
+  **
+  **   PRAGMA [schema.]application_id
+  **   PRAGMA [schema.]application_id = <integer>
+  **
+  ** The pragma's schema_version and user_version are used to set or get
+  ** the value of the schema-version and user-version, respectively. Both
+  ** the schema-version and the user-version are 32-bit signed integers
+  ** stored in the database header.
+  **
+  ** The schema-cookie is usually only manipulated internally by SQLite. It
+  ** is incremented by SQLite whenever the database schema is modified (by
+  ** creating or dropping a table or index). The schema version is used by
+  ** SQLite each time a query is executed to ensure that the internal cache
+  ** of the schema used when compiling the SQL query matches the schema of
+  ** the database against which the compiled query is actually executed.
+  ** Subverting this mechanism by using "PRAGMA schema_version" to modify
+  ** the schema-version is potentially dangerous and may lead to program
+  ** crashes or database corruption. Use with caution!
+  **
+  ** The user-version is not used internally by SQLite. It may be used by
+  ** applications for any purpose.
+  */
+  case PragTyp_HEADER_VALUE: {
+    int iCookie = pPragma->iArg;  /* Which cookie to read or write */
+    sqlite3VdbeUsesBtree(v, iDb);
+    if( zRight && (pPragma->mPragFlg & PragFlg_ReadOnly)==0 ){
+      /* Write the specified cookie value */
+      static const VdbeOpList setCookie[] = {
+        { OP_Transaction,    0,  1,  0},    /* 0 */
+        { OP_SetCookie,      0,  0,  0},    /* 1 */
+      };
+      VdbeOp *aOp;
+      sqlite3VdbeVerifyNoMallocRequired(v, ArraySize(setCookie));
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(setCookie), setCookie, 0);
+      if( ONLY_IF_REALLOC_STRESS(aOp==0) ) break;
+      aOp[0].p1 = iDb;
+      aOp[1].p1 = iDb;
+      aOp[1].p2 = iCookie;
+      aOp[1].p3 = sqlite3Atoi(zRight);
+      aOp[1].p5 = 1;
+      if( iCookie==BTREE_SCHEMA_VERSION && (db->flags & SQLITE_Defensive)!=0 ){
+        /* Do not allow the use of PRAGMA schema_version=VALUE in defensive
+        ** mode.  Change the OP_SetCookie opcode into a no-op.  */
+        aOp[1].opcode = OP_Noop;
+      }
+    }else{
+      /* Read the specified cookie value */
+      static const VdbeOpList readCookie[] = {
+        { OP_Transaction,     0,  0,  0},    /* 0 */
+        { OP_ReadCookie,      0,  1,  0},    /* 1 */
+        { OP_ResultRow,       1,  1,  0}
+      };
+      VdbeOp *aOp;
+      sqlite3VdbeVerifyNoMallocRequired(v, ArraySize(readCookie));
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(readCookie),readCookie,0);
+      if( ONLY_IF_REALLOC_STRESS(aOp==0) ) break;
+      aOp[0].p1 = iDb;
+      aOp[1].p1 = iDb;
+      aOp[1].p3 = iCookie;
+      sqlite3VdbeReusable(v);
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS */
+
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+  /*
+  **   PRAGMA compile_options
+  **
+  ** Return the names of all compile-time options used in this build,
+  ** one option per row.
+  */
+  case PragTyp_COMPILE_OPTIONS: {
+    int i = 0;
+    const char *zOpt;
+    pParse->nMem = 1;
+    while( (zOpt = sqlite3_compileoption_get(i++))!=0 ){
+      sqlite3VdbeLoadString(v, 1, zOpt);
+      sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+    }
+    sqlite3VdbeReusable(v);
+  }
+  break;
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+#ifndef SQLITE_OMIT_WAL
+  /*
+  **   PRAGMA [schema.]wal_checkpoint = passive|full|restart|truncate
+  **
+  ** Checkpoint the database.
+  */
+  case PragTyp_WAL_CHECKPOINT: {
+    int iBt = (pId2->z?iDb:SQLITE_MAX_DB);
+    int eMode = SQLITE_CHECKPOINT_PASSIVE;
+    if( zRight ){
+      if( sqlite3StrICmp(zRight, "full")==0 ){
+        eMode = SQLITE_CHECKPOINT_FULL;
+      }else if( sqlite3StrICmp(zRight, "restart")==0 ){
+        eMode = SQLITE_CHECKPOINT_RESTART;
+      }else if( sqlite3StrICmp(zRight, "truncate")==0 ){
+        eMode = SQLITE_CHECKPOINT_TRUNCATE;
+      }
+    }
+    pParse->nMem = 3;
+    sqlite3VdbeAddOp3(v, OP_Checkpoint, iBt, eMode, 1);
+    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 3);
+  }
+  break;
+
+  /*
+  **   PRAGMA wal_autocheckpoint
+  **   PRAGMA wal_autocheckpoint = N
+  **
+  ** Configure a database connection to automatically checkpoint a database
+  ** after accumulating N frames in the log. Or query for the current value
+  ** of N.
+  */
+  case PragTyp_WAL_AUTOCHECKPOINT: {
+    if( zRight ){
+      sqlite3_wal_autocheckpoint(db, sqlite3Atoi(zRight));
+    }
+    returnSingleInt(v,
+       db->xWalCallback==sqlite3WalDefaultHook ?
+           SQLITE_PTR_TO_INT(db->pWalArg) : 0);
+  }
+  break;
+#endif
+
+  /*
+  **  PRAGMA shrink_memory
+  **
+  ** IMPLEMENTATION-OF: R-23445-46109 This pragma causes the database
+  ** connection on which it is invoked to free up as much memory as it
+  ** can, by calling sqlite3_db_release_memory().
+  */
+  case PragTyp_SHRINK_MEMORY: {
+    sqlite3_db_release_memory(db);
+    break;
+  }
+
+  /*
+  **  PRAGMA optimize
+  **  PRAGMA optimize(MASK)
+  **  PRAGMA schema.optimize
+  **  PRAGMA schema.optimize(MASK)
+  **
+  ** Attempt to optimize the database.  All schemas are optimized in the first
+  ** two forms, and only the specified schema is optimized in the latter two.
+  **
+  ** The details of optimizations performed by this pragma are expected
+  ** to change and improve over time.  Applications should anticipate that
+  ** this pragma will perform new optimizations in future releases.
+  **
+  ** The optional argument is a bitmask of optimizations to perform:
+  **
+  **    0x00001    Debugging mode.  Do not actually perform any optimizations
+  **               but instead return one line of text for each optimization
+  **               that would have been done.  Off by default.
+  **
+  **    0x00002    Run ANALYZE on tables that might benefit.  On by default.
+  **               See below for additional information.
+  **
+  **    0x00010    Run all ANALYZE operations using an analysis_limit that
+  **               is the lessor of the current analysis_limit and the
+  **               SQLITE_DEFAULT_OPTIMIZE_LIMIT compile-time option.
+  **               The default value of SQLITE_DEFAULT_OPTIMIZE_LIMIT is
+  **               currently (2024-02-19) set to 2000, which is such that
+  **               the worst case run-time for PRAGMA optimize on a 100MB
+  **               database will usually be less than 100 milliseconds on
+  **               a RaspberryPI-4 class machine.  On by default.
+  **
+  **    0x10000    Look at tables to see if they need to be reanalyzed
+  **               due to growth or shrinkage even if they have not been
+  **               queried during the current connection.  Off by default.
+  **
+  ** The default MASK is and always shall be 0x0fffe.  In the current
+  ** implementation, the default mask only covers the 0x00002 optimization,
+  ** though additional optimizations that are covered by 0x0fffe might be
+  ** added in the future.  Optimizations that are off by default and must
+  ** be explicitly requested have masks of 0x10000 or greater.
+  **
+  ** DETERMINATION OF WHEN TO RUN ANALYZE
+  **
+  ** In the current implementation, a table is analyzed if only if all of
+  ** the following are true:
+  **
+  ** (1) MASK bit 0x00002 is set.
+  **
+  ** (2) The table is an ordinary table, not a virtual table or view.
+  **
+  ** (3) The table name does not begin with "sqlite_".
+  **
+  ** (4) One or more of the following is true:
+  **      (4a) The 0x10000 MASK bit is set.
+  **      (4b) One or more indexes on the table lacks an entry
+  **           in the sqlite_stat1 table.
+  **      (4c) The query planner used sqlite_stat1-style statistics for one
+  **           or more indexes of the table at some point during the lifetime
+  **           of the current connection.
+  **
+  ** (5) One or more of the following is true:
+  **      (5a) One or more indexes on the table lacks an entry
+  **           in the sqlite_stat1 table.  (Same as 4a)
+  **      (5b) The number of rows in the table has increased or decreased by
+  **           10-fold.  In other words, the current size of the table is
+  **           10 times larger than the size in sqlite_stat1 or else the
+  **           current size is less than 1/10th the size in sqlite_stat1.
+  **
+  ** The rules for when tables are analyzed are likely to change in
+  ** future releases.  Future versions of SQLite might accept a string
+  ** literal argument to this pragma that contains a mnemonic description
+  ** of the options rather than a bitmap.
+  */
+  case PragTyp_OPTIMIZE: {
+    int iDbLast;           /* Loop termination point for the schema loop */
+    int iTabCur;           /* Cursor for a table whose size needs checking */
+    HashElem *k;           /* Loop over tables of a schema */
+    Schema *pSchema;       /* The current schema */
+    Table *pTab;           /* A table in the schema */
+    Index *pIdx;           /* An index of the table */
+    LogEst szThreshold;    /* Size threshold above which reanalysis needed */
+    char *zSubSql;         /* SQL statement for the OP_SqlExec opcode */
+    u32 opMask;            /* Mask of operations to perform */
+    int nLimit;            /* Analysis limit to use */
+    int nCheck = 0;        /* Number of tables to be optimized */
+    int nBtree = 0;        /* Number of btrees to scan */
+    int nIndex;            /* Number of indexes on the current table */
+
+    if( zRight ){
+      opMask = (u32)sqlite3Atoi(zRight);
+      if( (opMask & 0x02)==0 ) break;
+    }else{
+      opMask = 0xfffe;
+    }
+    if( (opMask & 0x10)==0 ){
+      nLimit = 0;
+    }else if( db->nAnalysisLimit>0
+           && db->nAnalysisLimit<SQLITE_DEFAULT_OPTIMIZE_LIMIT ){
+      nLimit = 0;
+    }else{
+      nLimit = SQLITE_DEFAULT_OPTIMIZE_LIMIT;
+    }
+    iTabCur = pParse->nTab++;
+    for(iDbLast = zDb?iDb:db->nDb-1; iDb<=iDbLast; iDb++){
+      if( iDb==1 ) continue;
+      sqlite3CodeVerifySchema(pParse, iDb);
+      pSchema = db->aDb[iDb].pSchema;
+      for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
+        pTab = (Table*)sqliteHashData(k);
+
+        /* This only works for ordinary tables */
+        if( !IsOrdinaryTable(pTab) ) continue;
+
+        /* Do not scan system tables */
+        if( 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7) ) continue;
+
+        /* Find the size of the table as last recorded in sqlite_stat1.
+        ** If any index is unanalyzed, then the threshold is -1 to
+        ** indicate a new, unanalyzed index
+        */
+        szThreshold = pTab->nRowLogEst;
+        nIndex = 0;
+        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+          nIndex++;
+          if( !pIdx->hasStat1 ){
+            szThreshold = -1; /* Always analyze if any index lacks statistics */
+          }
+        }
+
+        /* If table pTab has not been used in a way that would benefit from
+        ** having analysis statistics during the current session, then skip it,
+        ** unless the 0x10000 MASK bit is set. */
+        if( (pTab->tabFlags & TF_MaybeReanalyze)!=0 ){
+          /* Check for size change if stat1 has been used for a query */
+        }else if( opMask & 0x10000 ){
+          /* Check for size change if 0x10000 is set */
+        }else if( pTab->pIndex!=0 && szThreshold<0 ){
+          /* Do analysis if unanalyzed indexes exists */
+        }else{
+          /* Otherwise, we can skip this table */
+          continue;
+        }
+
+        nCheck++;
+        if( nCheck==2 ){
+          /* If ANALYZE might be invoked two or more times, hold a write
+          ** transaction for efficiency */
+          sqlite3BeginWriteOperation(pParse, 0, iDb);
+        }
+        nBtree += nIndex+1;
+
+        /* Reanalyze if the table is 10 times larger or smaller than
+        ** the last analysis.  Unconditional reanalysis if there are
+        ** unanalyzed indexes. */
+        sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead);
+        if( szThreshold>=0 ){
+          const LogEst iRange = 33;   /* 10x size change */
+          sqlite3VdbeAddOp4Int(v, OP_IfSizeBetween, iTabCur,
+                         sqlite3VdbeCurrentAddr(v)+2+(opMask&1),
+                         szThreshold>=iRange ? szThreshold-iRange : -1,
+                         szThreshold+iRange);
+          VdbeCoverage(v);
+        }else{
+          sqlite3VdbeAddOp2(v, OP_Rewind, iTabCur,
+                         sqlite3VdbeCurrentAddr(v)+2+(opMask&1));
+          VdbeCoverage(v);
+        }
+        zSubSql = sqlite3MPrintf(db, "ANALYZE \"%w\".\"%w\"",
+                                 db->aDb[iDb].zDbSName, pTab->zName);
+        if( opMask & 0x01 ){
+          int r1 = sqlite3GetTempReg(pParse);
+          sqlite3VdbeAddOp4(v, OP_String8, 0, r1, 0, zSubSql, P4_DYNAMIC);
+          sqlite3VdbeAddOp2(v, OP_ResultRow, r1, 1);
+        }else{
+          sqlite3VdbeAddOp4(v, OP_SqlExec, nLimit ? 0x02 : 00, nLimit, 0,
+                            zSubSql, P4_DYNAMIC);
+        }
+      }
+    }
+    sqlite3VdbeAddOp0(v, OP_Expire);
+
+    /* In a schema with a large number of tables and indexes, scale back
+    ** the analysis_limit to avoid excess run-time in the worst case.
+    */
+    if( !db->mallocFailed && nLimit>0 && nBtree>100 ){
+      int iAddr, iEnd;
+      VdbeOp *aOp;
+      nLimit = 100*nLimit/nBtree;
+      if( nLimit<100 ) nLimit = 100;
+      aOp = sqlite3VdbeGetOp(v, 0);
+      iEnd = sqlite3VdbeCurrentAddr(v);
+      for(iAddr=0; iAddr<iEnd; iAddr++){
+        if( aOp[iAddr].opcode==OP_SqlExec ) aOp[iAddr].p2 = nLimit;
+      }
+    }
+    break;
+  }
+
+  /*
+  **   PRAGMA busy_timeout
+  **   PRAGMA busy_timeout = N
+  **
+  ** Call sqlite3_busy_timeout(db, N).  Return the current timeout value
+  ** if one is set.  If no busy handler or a different busy handler is set
+  ** then 0 is returned.  Setting the busy_timeout to 0 or negative
+  ** disables the timeout.
+  */
+  /*case PragTyp_BUSY_TIMEOUT*/ default: {
+    assert( pPragma->ePragTyp==PragTyp_BUSY_TIMEOUT );
+    if( zRight ){
+      sqlite3_busy_timeout(db, sqlite3Atoi(zRight));
+    }
+    returnSingleInt(v, db->busyTimeout);
+    break;
+  }
+
+  /*
+  **   PRAGMA soft_heap_limit
+  **   PRAGMA soft_heap_limit = N
+  **
+  ** IMPLEMENTATION-OF: R-26343-45930 This pragma invokes the
+  ** sqlite3_soft_heap_limit64() interface with the argument N, if N is
+  ** specified and is a non-negative integer.
+  ** IMPLEMENTATION-OF: R-64451-07163 The soft_heap_limit pragma always
+  ** returns the same integer that would be returned by the
+  ** sqlite3_soft_heap_limit64(-1) C-language function.
+  */
+  case PragTyp_SOFT_HEAP_LIMIT: {
+    sqlite3_int64 N;
+    if( zRight && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK ){
+      sqlite3_soft_heap_limit64(N);
+    }
+    returnSingleInt(v, sqlite3_soft_heap_limit64(-1));
+    break;
+  }
+
+  /*
+  **   PRAGMA hard_heap_limit
+  **   PRAGMA hard_heap_limit = N
+  **
+  ** Invoke sqlite3_hard_heap_limit64() to query or set the hard heap
+  ** limit.  The hard heap limit can be activated or lowered by this
+  ** pragma, but not raised or deactivated.  Only the
+  ** sqlite3_hard_heap_limit64() C-language API can raise or deactivate
+  ** the hard heap limit.  This allows an application to set a heap limit
+  ** constraint that cannot be relaxed by an untrusted SQL script.
+  */
+  case PragTyp_HARD_HEAP_LIMIT: {
+    sqlite3_int64 N;
+    if( zRight && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK ){
+      sqlite3_int64 iPrior = sqlite3_hard_heap_limit64(-1);
+      if( N>0 && (iPrior==0 || iPrior>N) ) sqlite3_hard_heap_limit64(N);
+    }
+    returnSingleInt(v, sqlite3_hard_heap_limit64(-1));
+    break;
+  }
+
+  /*
+  **   PRAGMA threads
+  **   PRAGMA threads = N
+  **
+  ** Configure the maximum number of worker threads.  Return the new
+  ** maximum, which might be less than requested.
+  */
+  case PragTyp_THREADS: {
+    sqlite3_int64 N;
+    if( zRight
+     && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK
+     && N>=0
+    ){
+      sqlite3_limit(db, SQLITE_LIMIT_WORKER_THREADS, (int)(N&0x7fffffff));
+    }
+    returnSingleInt(v, sqlite3_limit(db, SQLITE_LIMIT_WORKER_THREADS, -1));
+    break;
+  }
+
+  /*
+  **   PRAGMA analysis_limit
+  **   PRAGMA analysis_limit = N
+  **
+  ** Configure the maximum number of rows that ANALYZE will examine
+  ** in each index that it looks at.  Return the new limit.
+  */
+  case PragTyp_ANALYSIS_LIMIT: {
+    sqlite3_int64 N;
+    if( zRight
+     && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK /* IMP: R-40975-20399 */
+     && N>=0
+    ){
+      db->nAnalysisLimit = (int)(N&0x7fffffff);
+    }
+    returnSingleInt(v, db->nAnalysisLimit); /* IMP: R-57594-65522 */
+    break;
+  }
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /*
+  ** Report the current state of file logs for all databases
+  */
+  case PragTyp_LOCK_STATUS: {
+    static const char *const azLockName[] = {
+      "unlocked", "shared", "reserved", "pending", "exclusive"
+    };
+    int i;
+    pParse->nMem = 2;
+    for(i=0; i<db->nDb; i++){
+      Btree *pBt;
+      const char *zState = "unknown";
+      int j;
+      if( db->aDb[i].zDbSName==0 ) continue;
+      pBt = db->aDb[i].pBt;
+      if( pBt==0 || sqlite3BtreePager(pBt)==0 ){
+        zState = "closed";
+      }else if( sqlite3_file_control(db, i ? db->aDb[i].zDbSName : 0,
+                                     SQLITE_FCNTL_LOCKSTATE, &j)==SQLITE_OK ){
+         zState = azLockName[j];
+      }
+      sqlite3VdbeMultiLoad(v, 1, "ss", db->aDb[i].zDbSName, zState);
+    }
+    break;
+  }
+#endif
+
+#if defined(SQLITE_ENABLE_CEROD)
+  case PragTyp_ACTIVATE_EXTENSIONS: if( zRight ){
+    if( sqlite3StrNICmp(zRight, "cerod-", 6)==0 ){
+      sqlite3_activate_cerod(&zRight[6]);
+    }
+  }
+  break;
+#endif
+
+  } /* End of the PRAGMA switch */
+
+  /* The following block is a no-op unless SQLITE_DEBUG is defined. Its only
+  ** purpose is to execute assert() statements to verify that if the
+  ** PragFlg_NoColumns1 flag is set and the caller specified an argument
+  ** to the PRAGMA, the implementation has not added any OP_ResultRow
+  ** instructions to the VM.  */
+  if( (pPragma->mPragFlg & PragFlg_NoColumns1) && zRight ){
+    sqlite3VdbeVerifyNoResultRow(v);
+  }
+
+pragma_out:
+  sqlite3DbFree(db, zLeft);
+  sqlite3DbFree(db, zRight);
+}
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*****************************************************************************
+** Implementation of an eponymous virtual table that runs a pragma.
+**
+*/
+typedef struct PragmaVtab PragmaVtab;
+typedef struct PragmaVtabCursor PragmaVtabCursor;
+struct PragmaVtab {
+  sqlite3_vtab base;        /* Base class.  Must be first */
+  sqlite3 *db;              /* The database connection to which it belongs */
+  const PragmaName *pName;  /* Name of the pragma */
+  u8 nHidden;               /* Number of hidden columns */
+  u8 iHidden;               /* Index of the first hidden column */
+};
+struct PragmaVtabCursor {
+  sqlite3_vtab_cursor base; /* Base class.  Must be first */
+  sqlite3_stmt *pPragma;    /* The pragma statement to run */
+  sqlite_int64 iRowid;      /* Current rowid */
+  char *azArg[2];           /* Value of the argument and schema */
+};
+
+/*
+** Pragma virtual table module xConnect method.
+*/
+static int pragmaVtabConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  const PragmaName *pPragma = (const PragmaName*)pAux;
+  PragmaVtab *pTab = 0;
+  int rc;
+  int i, j;
+  char cSep = '(';
+  StrAccum acc;
+  char zBuf[200];
+
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+  sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+  sqlite3_str_appendall(&acc, "CREATE TABLE x");
+  for(i=0, j=pPragma->iPragCName; i<pPragma->nPragCName; i++, j++){
+    sqlite3_str_appendf(&acc, "%c\"%s\"", cSep, pragCName[j]);
+    cSep = ',';
+  }
+  if( i==0 ){
+    sqlite3_str_appendf(&acc, "(\"%s\"", pPragma->zName);
+    i++;
+  }
+  j = 0;
+  if( pPragma->mPragFlg & PragFlg_Result1 ){
+    sqlite3_str_appendall(&acc, ",arg HIDDEN");
+    j++;
+  }
+  if( pPragma->mPragFlg & (PragFlg_SchemaOpt|PragFlg_SchemaReq) ){
+    sqlite3_str_appendall(&acc, ",schema HIDDEN");
+    j++;
+  }
+  sqlite3_str_append(&acc, ")", 1);
+  sqlite3StrAccumFinish(&acc);
+  assert( strlen(zBuf) < sizeof(zBuf)-1 );
+  rc = sqlite3_declare_vtab(db, zBuf);
+  if( rc==SQLITE_OK ){
+    pTab = (PragmaVtab*)sqlite3_malloc(sizeof(PragmaVtab));
+    if( pTab==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pTab, 0, sizeof(PragmaVtab));
+      pTab->pName = pPragma;
+      pTab->db = db;
+      pTab->iHidden = i;
+      pTab->nHidden = j;
+    }
+  }else{
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+  }
+
+  *ppVtab = (sqlite3_vtab*)pTab;
+  return rc;
+}
+
+/*
+** Pragma virtual table module xDisconnect method.
+*/
+static int pragmaVtabDisconnect(sqlite3_vtab *pVtab){
+  PragmaVtab *pTab = (PragmaVtab*)pVtab;
+  sqlite3_free(pTab);
+  return SQLITE_OK;
+}
+
+/* Figure out the best index to use to search a pragma virtual table.
+**
+** There are not really any index choices.  But we want to encourage the
+** query planner to give == constraints on as many hidden parameters as
+** possible, and especially on the first hidden parameter.  So return a
+** high cost if hidden parameters are unconstrained.
+*/
+static int pragmaVtabBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  PragmaVtab *pTab = (PragmaVtab*)tab;
+  const struct sqlite3_index_constraint *pConstraint;
+  int i, j;
+  int seen[2];
+
+  pIdxInfo->estimatedCost = (double)1;
+  if( pTab->nHidden==0 ){ return SQLITE_OK; }
+  pConstraint = pIdxInfo->aConstraint;
+  seen[0] = 0;
+  seen[1] = 0;
+  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
+    if( pConstraint->iColumn < pTab->iHidden ) continue;
+    if( pConstraint->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
+    if( pConstraint->usable==0 ) return SQLITE_CONSTRAINT;
+    j = pConstraint->iColumn - pTab->iHidden;
+    assert( j < 2 );
+    seen[j] = i+1;
+  }
+  if( seen[0]==0 ){
+    pIdxInfo->estimatedCost = (double)2147483647;
+    pIdxInfo->estimatedRows = 2147483647;
+    return SQLITE_OK;
+  }
+  j = seen[0]-1;
+  pIdxInfo->aConstraintUsage[j].argvIndex = 1;
+  pIdxInfo->aConstraintUsage[j].omit = 1;
+  pIdxInfo->estimatedCost = (double)20;
+  pIdxInfo->estimatedRows = 20;
+  if( seen[1] ){
+    j = seen[1]-1;
+    pIdxInfo->aConstraintUsage[j].argvIndex = 2;
+    pIdxInfo->aConstraintUsage[j].omit = 1;
+  }
+  return SQLITE_OK;
+}
+
+/* Create a new cursor for the pragma virtual table */
+static int pragmaVtabOpen(sqlite3_vtab *pVtab, sqlite3_vtab_cursor **ppCursor){
+  PragmaVtabCursor *pCsr;
+  pCsr = (PragmaVtabCursor*)sqlite3_malloc(sizeof(*pCsr));
+  if( pCsr==0 ) return SQLITE_NOMEM;
+  memset(pCsr, 0, sizeof(PragmaVtabCursor));
+  pCsr->base.pVtab = pVtab;
+  *ppCursor = &pCsr->base;
+  return SQLITE_OK;
+}
+
+/* Clear all content from pragma virtual table cursor. */
+static void pragmaVtabCursorClear(PragmaVtabCursor *pCsr){
+  int i;
+  sqlite3_finalize(pCsr->pPragma);
+  pCsr->pPragma = 0;
+  pCsr->iRowid = 0;
+  for(i=0; i<ArraySize(pCsr->azArg); i++){
+    sqlite3_free(pCsr->azArg[i]);
+    pCsr->azArg[i] = 0;
+  }
+}
+
+/* Close a pragma virtual table cursor */
+static int pragmaVtabClose(sqlite3_vtab_cursor *cur){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)cur;
+  pragmaVtabCursorClear(pCsr);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/* Advance the pragma virtual table cursor to the next row */
+static int pragmaVtabNext(sqlite3_vtab_cursor *pVtabCursor){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  int rc = SQLITE_OK;
+
+  /* Increment the xRowid value */
+  pCsr->iRowid++;
+  assert( pCsr->pPragma );
+  if( SQLITE_ROW!=sqlite3_step(pCsr->pPragma) ){
+    rc = sqlite3_finalize(pCsr->pPragma);
+    pCsr->pPragma = 0;
+    pragmaVtabCursorClear(pCsr);
+  }
+  return rc;
+}
+
+/*
+** Pragma virtual table module xFilter method.
+*/
+static int pragmaVtabFilter(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  PragmaVtab *pTab = (PragmaVtab*)(pVtabCursor->pVtab);
+  int rc;
+  int i, j;
+  StrAccum acc;
+  char *zSql;
+
+  UNUSED_PARAMETER(idxNum);
+  UNUSED_PARAMETER(idxStr);
+  pragmaVtabCursorClear(pCsr);
+  j = (pTab->pName->mPragFlg & PragFlg_Result1)!=0 ? 0 : 1;
+  for(i=0; i<argc; i++, j++){
+    const char *zText = (const char*)sqlite3_value_text(argv[i]);
+    assert( j<ArraySize(pCsr->azArg) );
+    assert( pCsr->azArg[j]==0 );
+    if( zText ){
+      pCsr->azArg[j] = sqlite3_mprintf("%s", zText);
+      if( pCsr->azArg[j]==0 ){
+        return SQLITE_NOMEM;
+      }
+    }
+  }
+  sqlite3StrAccumInit(&acc, 0, 0, 0, pTab->db->aLimit[SQLITE_LIMIT_SQL_LENGTH]);
+  sqlite3_str_appendall(&acc, "PRAGMA ");
+  if( pCsr->azArg[1] ){
+    sqlite3_str_appendf(&acc, "%Q.", pCsr->azArg[1]);
+  }
+  sqlite3_str_appendall(&acc, pTab->pName->zName);
+  if( pCsr->azArg[0] ){
+    sqlite3_str_appendf(&acc, "=%Q", pCsr->azArg[0]);
+  }
+  zSql = sqlite3StrAccumFinish(&acc);
+  if( zSql==0 ) return SQLITE_NOMEM;
+  rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pPragma, 0);
+  sqlite3_free(zSql);
+  if( rc!=SQLITE_OK ){
+    pTab->base.zErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pTab->db));
+    return rc;
+  }
+  return pragmaVtabNext(pVtabCursor);
+}
+
+/*
+** Pragma virtual table module xEof method.
+*/
+static int pragmaVtabEof(sqlite3_vtab_cursor *pVtabCursor){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  return (pCsr->pPragma==0);
+}
+
+/* The xColumn method simply returns the corresponding column from
+** the PRAGMA.
+*/
+static int pragmaVtabColumn(
+  sqlite3_vtab_cursor *pVtabCursor,
+  sqlite3_context *ctx,
+  int i
+){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  PragmaVtab *pTab = (PragmaVtab*)(pVtabCursor->pVtab);
+  if( i<pTab->iHidden ){
+    sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pPragma, i));
+  }else{
+    sqlite3_result_text(ctx, pCsr->azArg[i-pTab->iHidden],-1,SQLITE_TRANSIENT);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Pragma virtual table module xRowid method.
+*/
+static int pragmaVtabRowid(sqlite3_vtab_cursor *pVtabCursor, sqlite_int64 *p){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  *p = pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/* The pragma virtual table object */
+static const sqlite3_module pragmaVtabModule = {
+  0,                           /* iVersion */
+  0,                           /* xCreate - create a table */
+  pragmaVtabConnect,           /* xConnect - connect to an existing table */
+  pragmaVtabBestIndex,         /* xBestIndex - Determine search strategy */
+  pragmaVtabDisconnect,        /* xDisconnect - Disconnect from a table */
+  0,                           /* xDestroy - Drop a table */
+  pragmaVtabOpen,              /* xOpen - open a cursor */
+  pragmaVtabClose,             /* xClose - close a cursor */
+  pragmaVtabFilter,            /* xFilter - configure scan constraints */
+  pragmaVtabNext,              /* xNext - advance a cursor */
+  pragmaVtabEof,               /* xEof */
+  pragmaVtabColumn,            /* xColumn - read data */
+  pragmaVtabRowid,             /* xRowid - read data */
+  0,                           /* xUpdate - write data */
+  0,                           /* xBegin - begin transaction */
+  0,                           /* xSync - sync transaction */
+  0,                           /* xCommit - commit transaction */
+  0,                           /* xRollback - rollback transaction */
+  0,                           /* xFindFunction - function overloading */
+  0,                           /* xRename - rename the table */
+  0,                           /* xSavepoint */
+  0,                           /* xRelease */
+  0,                           /* xRollbackTo */
+  0,                           /* xShadowName */
+  0                            /* xIntegrity */
+};
+
+/*
+** Check to see if zTabName is really the name of a pragma.  If it is,
+** then register an eponymous virtual table for that pragma and return
+** a pointer to the Module object for the new virtual table.
+*/
+SQLITE_PRIVATE Module *sqlite3PragmaVtabRegister(sqlite3 *db, const char *zName){
+  const PragmaName *pName;
+  assert( sqlite3_strnicmp(zName, "pragma_", 7)==0 );
+  pName = pragmaLocate(zName+7);
+  if( pName==0 ) return 0;
+  if( (pName->mPragFlg & (PragFlg_Result0|PragFlg_Result1))==0 ) return 0;
+  assert( sqlite3HashFind(&db->aModule, zName)==0 );
+  return sqlite3VtabCreateModule(db, zName, &pragmaVtabModule, (void*)pName, 0);
+}
+
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#endif /* SQLITE_OMIT_PRAGMA */
+
+/************** End of pragma.c **********************************************/
+/************** Begin file prepare.c *****************************************/
+/*
+** 2005 May 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the implementation of the sqlite3_prepare()
+** interface, and routines that contribute to loading the database schema
+** from disk.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** Fill the InitData structure with an error message that indicates
+** that the database is corrupt.
+*/
+static void corruptSchema(
+  InitData *pData,     /* Initialization context */
+  char **azObj,        /* Type and name of object being parsed */
+  const char *zExtra   /* Error information */
+){
+  sqlite3 *db = pData->db;
+  if( db->mallocFailed ){
+    pData->rc = SQLITE_NOMEM_BKPT;
+  }else if( pData->pzErrMsg[0]!=0 ){
+    /* A error message has already been generated.  Do not overwrite it */
+  }else if( pData->mInitFlags & (INITFLAG_AlterMask) ){
+    static const char *azAlterType[] = {
+       "rename",
+       "drop column",
+       "add column"
+    };
+    *pData->pzErrMsg = sqlite3MPrintf(db,
+        "error in %s %s after %s: %s", azObj[0], azObj[1],
+        azAlterType[(pData->mInitFlags&INITFLAG_AlterMask)-1],
+        zExtra
+    );
+    pData->rc = SQLITE_ERROR;
+  }else if( db->flags & SQLITE_WriteSchema ){
+    pData->rc = SQLITE_CORRUPT_BKPT;
+  }else{
+    char *z;
+    const char *zObj = azObj[1] ? azObj[1] : "?";
+    z = sqlite3MPrintf(db, "malformed database schema (%s)", zObj);
+    if( zExtra && zExtra[0] ) z = sqlite3MPrintf(db, "%z - %s", z, zExtra);
+    *pData->pzErrMsg = z;
+    pData->rc = SQLITE_CORRUPT_BKPT;
+  }
+}
+
+/*
+** Check to see if any sibling index (another index on the same table)
+** of pIndex has the same root page number, and if it does, return true.
+** This would indicate a corrupt schema.
+*/
+SQLITE_PRIVATE int sqlite3IndexHasDuplicateRootPage(Index *pIndex){
+  Index *p;
+  for(p=pIndex->pTable->pIndex; p; p=p->pNext){
+    if( p->tnum==pIndex->tnum && p!=pIndex ) return 1;
+  }
+  return 0;
+}
+
+/* forward declaration */
+static int sqlite3Prepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  u32 prepFlags,            /* Zero or more SQLITE_PREPARE_* flags */
+  Vdbe *pReprepare,         /* VM being reprepared */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+);
+
+
+/*
+** This is the callback routine for the code that initializes the
+** database.  See sqlite3Init() below for additional information.
+** This routine is also called from the OP_ParseSchema opcode of the VDBE.
+**
+** Each callback contains the following information:
+**
+**     argv[0] = type of object: "table", "index", "trigger", or "view".
+**     argv[1] = name of thing being created
+**     argv[2] = associated table if an index or trigger
+**     argv[3] = root page number for table or index. 0 for trigger or view.
+**     argv[4] = SQL text for the CREATE statement.
+**
+*/
+SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char **NotUsed){
+  InitData *pData = (InitData*)pInit;
+  sqlite3 *db = pData->db;
+  int iDb = pData->iDb;
+
+  assert( argc==5 );
+  UNUSED_PARAMETER2(NotUsed, argc);
+  assert( sqlite3_mutex_held(db->mutex) );
+  db->mDbFlags |= DBFLAG_EncodingFixed;
+  if( argv==0 ) return 0;   /* Might happen if EMPTY_RESULT_CALLBACKS are on */
+  pData->nInitRow++;
+  if( db->mallocFailed ){
+    corruptSchema(pData, argv, 0);
+    return 1;
+  }
+
+  assert( iDb>=0 && iDb<db->nDb );
+  if( argv[3]==0 ){
+    corruptSchema(pData, argv, 0);
+  }else if( argv[4]
+         && 'c'==sqlite3UpperToLower[(unsigned char)argv[4][0]]
+         && 'r'==sqlite3UpperToLower[(unsigned char)argv[4][1]] ){
+    /* Call the parser to process a CREATE TABLE, INDEX or VIEW.
+    ** But because db->init.busy is set to 1, no VDBE code is generated
+    ** or executed.  All the parser does is build the internal data
+    ** structures that describe the table, index, or view.
+    **
+    ** No other valid SQL statement, other than the variable CREATE statements,
+    ** can begin with the letters "C" and "R".  Thus, it is not possible run
+    ** any other kind of statement while parsing the schema, even a corrupt
+    ** schema.
+    */
+    int rc;
+    u8 saved_iDb = db->init.iDb;
+    sqlite3_stmt *pStmt;
+    TESTONLY(int rcp);            /* Return code from sqlite3_prepare() */
+
+    assert( db->init.busy );
+    db->init.iDb = iDb;
+    if( sqlite3GetUInt32(argv[3], &db->init.newTnum)==0
+     || (db->init.newTnum>pData->mxPage && pData->mxPage>0)
+    ){
+      if( sqlite3Config.bExtraSchemaChecks ){
+        corruptSchema(pData, argv, "invalid rootpage");
+      }
+    }
+    db->init.orphanTrigger = 0;
+    db->init.azInit = (const char**)argv;
+    pStmt = 0;
+    TESTONLY(rcp = ) sqlite3Prepare(db, argv[4], -1, 0, 0, &pStmt, 0);
+    rc = db->errCode;
+    assert( (rc&0xFF)==(rcp&0xFF) );
+    db->init.iDb = saved_iDb;
+    /* assert( saved_iDb==0 || (db->mDbFlags & DBFLAG_Vacuum)!=0 ); */
+    if( SQLITE_OK!=rc ){
+      if( db->init.orphanTrigger ){
+        assert( iDb==1 );
+      }else{
+        if( rc > pData->rc ) pData->rc = rc;
+        if( rc==SQLITE_NOMEM ){
+          sqlite3OomFault(db);
+        }else if( rc!=SQLITE_INTERRUPT && (rc&0xFF)!=SQLITE_LOCKED ){
+          corruptSchema(pData, argv, sqlite3_errmsg(db));
+        }
+      }
+    }
+    db->init.azInit = sqlite3StdType; /* Any array of string ptrs will do */
+    sqlite3_finalize(pStmt);
+  }else if( argv[1]==0 || (argv[4]!=0 && argv[4][0]!=0) ){
+    corruptSchema(pData, argv, 0);
+  }else{
+    /* If the SQL column is blank it means this is an index that
+    ** was created to be the PRIMARY KEY or to fulfill a UNIQUE
+    ** constraint for a CREATE TABLE.  The index should have already
+    ** been created when we processed the CREATE TABLE.  All we have
+    ** to do here is record the root page number for that index.
+    */
+    Index *pIndex;
+    pIndex = sqlite3FindIndex(db, argv[1], db->aDb[iDb].zDbSName);
+    if( pIndex==0 ){
+      corruptSchema(pData, argv, "orphan index");
+    }else
+    if( sqlite3GetUInt32(argv[3],&pIndex->tnum)==0
+     || pIndex->tnum<2
+     || pIndex->tnum>pData->mxPage
+     || sqlite3IndexHasDuplicateRootPage(pIndex)
+    ){
+      if( sqlite3Config.bExtraSchemaChecks ){
+        corruptSchema(pData, argv, "invalid rootpage");
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Attempt to read the database schema and initialize internal
+** data structures for a single database file.  The index of the
+** database file is given by iDb.  iDb==0 is used for the main
+** database.  iDb==1 should never be used.  iDb>=2 is used for
+** auxiliary databases.  Return one of the SQLITE_ error codes to
+** indicate success or failure.
+*/
+SQLITE_PRIVATE int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){
+  int rc;
+  int i;
+#ifndef SQLITE_OMIT_DEPRECATED
+  int size;
+#endif
+  Db *pDb;
+  char const *azArg[6];
+  int meta[5];
+  InitData initData;
+  const char *zSchemaTabName;
+  int openedTransaction = 0;
+  int mask = ((db->mDbFlags & DBFLAG_EncodingFixed) | ~DBFLAG_EncodingFixed);
+
+  assert( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0 );
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( db->aDb[iDb].pSchema );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
+
+  db->init.busy = 1;
+
+  /* Construct the in-memory representation schema tables (sqlite_schema or
+  ** sqlite_temp_schema) by invoking the parser directly.  The appropriate
+  ** table name will be inserted automatically by the parser so we can just
+  ** use the abbreviation "x" here.  The parser will also automatically tag
+  ** the schema table as read-only. */
+  azArg[0] = "table";
+  azArg[1] = zSchemaTabName = SCHEMA_TABLE(iDb);
+  azArg[2] = azArg[1];
+  azArg[3] = "1";
+  azArg[4] = "CREATE TABLE x(type text,name text,tbl_name text,"
+                            "rootpage int,sql text)";
+  azArg[5] = 0;
+  initData.db = db;
+  initData.iDb = iDb;
+  initData.rc = SQLITE_OK;
+  initData.pzErrMsg = pzErrMsg;
+  initData.mInitFlags = mFlags;
+  initData.nInitRow = 0;
+  initData.mxPage = 0;
+  sqlite3InitCallback(&initData, 5, (char **)azArg, 0);
+  db->mDbFlags &= mask;
+  if( initData.rc ){
+    rc = initData.rc;
+    goto error_out;
+  }
+
+  /* Create a cursor to hold the database open
+  */
+  pDb = &db->aDb[iDb];
+  if( pDb->pBt==0 ){
+    assert( iDb==1 );
+    DbSetProperty(db, 1, DB_SchemaLoaded);
+    rc = SQLITE_OK;
+    goto error_out;
+  }
+
+  /* If there is not already a read-only (or read-write) transaction opened
+  ** on the b-tree database, open one now. If a transaction is opened, it
+  ** will be closed before this function returns.  */
+  sqlite3BtreeEnter(pDb->pBt);
+  if( sqlite3BtreeTxnState(pDb->pBt)==SQLITE_TXN_NONE ){
+    rc = sqlite3BtreeBeginTrans(pDb->pBt, 0, 0);
+    if( rc!=SQLITE_OK ){
+      sqlite3SetString(pzErrMsg, db, sqlite3ErrStr(rc));
+      goto initone_error_out;
+    }
+    openedTransaction = 1;
+  }
+
+  /* Get the database meta information.
+  **
+  ** Meta values are as follows:
+  **    meta[0]   Schema cookie.  Changes with each schema change.
+  **    meta[1]   File format of schema layer.
+  **    meta[2]   Size of the page cache.
+  **    meta[3]   Largest rootpage (auto/incr_vacuum mode)
+  **    meta[4]   Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE
+  **    meta[5]   User version
+  **    meta[6]   Incremental vacuum mode
+  **    meta[7]   unused
+  **    meta[8]   unused
+  **    meta[9]   unused
+  **
+  ** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
+  ** the possible values of meta[4].
+  */
+  for(i=0; i<ArraySize(meta); i++){
+    sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
+  }
+  if( (db->flags & SQLITE_ResetDatabase)!=0 ){
+    memset(meta, 0, sizeof(meta));
+  }
+  pDb->pSchema->schema_cookie = meta[BTREE_SCHEMA_VERSION-1];
+
+  /* If opening a non-empty database, check the text encoding. For the
+  ** main database, set sqlite3.enc to the encoding of the main database.
+  ** For an attached db, it is an error if the encoding is not the same
+  ** as sqlite3.enc.
+  */
+  if( meta[BTREE_TEXT_ENCODING-1] ){  /* text encoding */
+    if( iDb==0 && (db->mDbFlags & DBFLAG_EncodingFixed)==0 ){
+      u8 encoding;
+#ifndef SQLITE_OMIT_UTF16
+      /* If opening the main database, set ENC(db). */
+      encoding = (u8)meta[BTREE_TEXT_ENCODING-1] & 3;
+      if( encoding==0 ) encoding = SQLITE_UTF8;
+#else
+      encoding = SQLITE_UTF8;
+#endif
+      sqlite3SetTextEncoding(db, encoding);
+    }else{
+      /* If opening an attached database, the encoding much match ENC(db) */
+      if( (meta[BTREE_TEXT_ENCODING-1] & 3)!=ENC(db) ){
+        sqlite3SetString(pzErrMsg, db, "attached databases must use the same"
+            " text encoding as main database");
+        rc = SQLITE_ERROR;
+        goto initone_error_out;
+      }
+    }
+  }
+  pDb->pSchema->enc = ENC(db);
+
+  if( pDb->pSchema->cache_size==0 ){
+#ifndef SQLITE_OMIT_DEPRECATED
+    size = sqlite3AbsInt32(meta[BTREE_DEFAULT_CACHE_SIZE-1]);
+    if( size==0 ){ size = SQLITE_DEFAULT_CACHE_SIZE; }
+    pDb->pSchema->cache_size = size;
+#else
+    pDb->pSchema->cache_size = SQLITE_DEFAULT_CACHE_SIZE;
+#endif
+    sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
+  }
+
+  /*
+  ** file_format==1    Version 3.0.0.
+  ** file_format==2    Version 3.1.3.  // ALTER TABLE ADD COLUMN
+  ** file_format==3    Version 3.1.4.  // ditto but with non-NULL defaults
+  ** file_format==4    Version 3.3.0.  // DESC indices.  Boolean constants
+  */
+  pDb->pSchema->file_format = (u8)meta[BTREE_FILE_FORMAT-1];
+  if( pDb->pSchema->file_format==0 ){
+    pDb->pSchema->file_format = 1;
+  }
+  if( pDb->pSchema->file_format>SQLITE_MAX_FILE_FORMAT ){
+    sqlite3SetString(pzErrMsg, db, "unsupported file format");
+    rc = SQLITE_ERROR;
+    goto initone_error_out;
+  }
+
+  /* Ticket #2804:  When we open a database in the newer file format,
+  ** clear the legacy_file_format pragma flag so that a VACUUM will
+  ** not downgrade the database and thus invalidate any descending
+  ** indices that the user might have created.
+  */
+  if( iDb==0 && meta[BTREE_FILE_FORMAT-1]>=4 ){
+    db->flags &= ~(u64)SQLITE_LegacyFileFmt;
+  }
+
+  /* Read the schema information out of the schema tables
+  */
+  assert( db->init.busy );
+  initData.mxPage = sqlite3BtreeLastPage(pDb->pBt);
+  {
+    char *zSql;
+    zSql = sqlite3MPrintf(db,
+        "SELECT*FROM\"%w\".%s ORDER BY rowid",
+        db->aDb[iDb].zDbSName, zSchemaTabName);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    {
+      sqlite3_xauth xAuth;
+      xAuth = db->xAuth;
+      db->xAuth = 0;
+#endif
+      rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+      db->xAuth = xAuth;
+    }
+#endif
+    if( rc==SQLITE_OK ) rc = initData.rc;
+    sqlite3DbFree(db, zSql);
+#ifndef SQLITE_OMIT_ANALYZE
+    if( rc==SQLITE_OK ){
+      sqlite3AnalysisLoad(db, iDb);
+    }
+#endif
+  }
+  assert( pDb == &(db->aDb[iDb]) );
+  if( db->mallocFailed ){
+    rc = SQLITE_NOMEM_BKPT;
+    sqlite3ResetAllSchemasOfConnection(db);
+    pDb = &db->aDb[iDb];
+  }else
+  if( rc==SQLITE_OK || ((db->flags&SQLITE_NoSchemaError) && rc!=SQLITE_NOMEM)){
+    /* Hack: If the SQLITE_NoSchemaError flag is set, then consider
+    ** the schema loaded, even if errors (other than OOM) occurred. In
+    ** this situation the current sqlite3_prepare() operation will fail,
+    ** but the following one will attempt to compile the supplied statement
+    ** against whatever subset of the schema was loaded before the error
+    ** occurred.
+    **
+    ** The primary purpose of this is to allow access to the sqlite_schema
+    ** table even when its contents have been corrupted.
+    */
+    DbSetProperty(db, iDb, DB_SchemaLoaded);
+    rc = SQLITE_OK;
+  }
+
+  /* Jump here for an error that occurs after successfully allocating
+  ** curMain and calling sqlite3BtreeEnter(). For an error that occurs
+  ** before that point, jump to error_out.
+  */
+initone_error_out:
+  if( openedTransaction ){
+    sqlite3BtreeCommit(pDb->pBt);
+  }
+  sqlite3BtreeLeave(pDb->pBt);
+
+error_out:
+  if( rc ){
+    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
+      sqlite3OomFault(db);
+    }
+    sqlite3ResetOneSchema(db, iDb);
+  }
+  db->init.busy = 0;
+  return rc;
+}
+
+/*
+** Initialize all database files - the main database file, the file
+** used to store temporary tables, and any additional database files
+** created using ATTACH statements.  Return a success code.  If an
+** error occurs, write an error message into *pzErrMsg.
+**
+** After a database is initialized, the DB_SchemaLoaded bit is set
+** bit is set in the flags field of the Db structure.
+*/
+SQLITE_PRIVATE int sqlite3Init(sqlite3 *db, char **pzErrMsg){
+  int i, rc;
+  int commit_internal = !(db->mDbFlags&DBFLAG_SchemaChange);
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( sqlite3BtreeHoldsMutex(db->aDb[0].pBt) );
+  assert( db->init.busy==0 );
+  ENC(db) = SCHEMA_ENC(db);
+  assert( db->nDb>0 );
+  /* Do the main schema first */
+  if( !DbHasProperty(db, 0, DB_SchemaLoaded) ){
+    rc = sqlite3InitOne(db, 0, pzErrMsg, 0);
+    if( rc ) return rc;
+  }
+  /* All other schemas after the main schema. The "temp" schema must be last */
+  for(i=db->nDb-1; i>0; i--){
+    assert( i==1 || sqlite3BtreeHoldsMutex(db->aDb[i].pBt) );
+    if( !DbHasProperty(db, i, DB_SchemaLoaded) ){
+      rc = sqlite3InitOne(db, i, pzErrMsg, 0);
+      if( rc ) return rc;
+    }
+  }
+  if( commit_internal ){
+    sqlite3CommitInternalChanges(db);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This routine is a no-op if the database schema is already initialized.
+** Otherwise, the schema is loaded. An error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3ReadSchema(Parse *pParse){
+  int rc = SQLITE_OK;
+  sqlite3 *db = pParse->db;
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( !db->init.busy ){
+    rc = sqlite3Init(db, &pParse->zErrMsg);
+    if( rc!=SQLITE_OK ){
+      pParse->rc = rc;
+      pParse->nErr++;
+    }else if( db->noSharedCache ){
+      db->mDbFlags |= DBFLAG_SchemaKnownOk;
+    }
+  }
+  return rc;
+}
+
+
+/*
+** Check schema cookies in all databases.  If any cookie is out
+** of date set pParse->rc to SQLITE_SCHEMA.  If all schema cookies
+** make no changes to pParse->rc.
+*/
+static void schemaIsValid(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  int iDb;
+  int rc;
+  int cookie;
+
+  assert( pParse->checkSchema );
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(iDb=0; iDb<db->nDb; iDb++){
+    int openedTransaction = 0;         /* True if a transaction is opened */
+    Btree *pBt = db->aDb[iDb].pBt;     /* Btree database to read cookie from */
+    if( pBt==0 ) continue;
+
+    /* If there is not already a read-only (or read-write) transaction opened
+    ** on the b-tree database, open one now. If a transaction is opened, it
+    ** will be closed immediately after reading the meta-value. */
+    if( sqlite3BtreeTxnState(pBt)==SQLITE_TXN_NONE ){
+      rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
+      if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
+        sqlite3OomFault(db);
+        pParse->rc = SQLITE_NOMEM;
+      }
+      if( rc!=SQLITE_OK ) return;
+      openedTransaction = 1;
+    }
+
+    /* Read the schema cookie from the database. If it does not match the
+    ** value stored as part of the in-memory schema representation,
+    ** set Parse.rc to SQLITE_SCHEMA. */
+    sqlite3BtreeGetMeta(pBt, BTREE_SCHEMA_VERSION, (u32 *)&cookie);
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( cookie!=db->aDb[iDb].pSchema->schema_cookie ){
+      if( DbHasProperty(db, iDb, DB_SchemaLoaded) ) pParse->rc = SQLITE_SCHEMA;
+      sqlite3ResetOneSchema(db, iDb);
+    }
+
+    /* Close the transaction, if one was opened. */
+    if( openedTransaction ){
+      sqlite3BtreeCommit(pBt);
+    }
+  }
+}
+
+/*
+** Convert a schema pointer into the iDb index that indicates
+** which database file in db->aDb[] the schema refers to.
+**
+** If the same database is attached more than once, the first
+** attached database is returned.
+*/
+SQLITE_PRIVATE int sqlite3SchemaToIndex(sqlite3 *db, Schema *pSchema){
+  int i = -32768;
+
+  /* If pSchema is NULL, then return -32768. This happens when code in
+  ** expr.c is trying to resolve a reference to a transient table (i.e. one
+  ** created by a sub-select). In this case the return value of this
+  ** function should never be used.
+  **
+  ** We return -32768 instead of the more usual -1 simply because using
+  ** -32768 as the incorrect index into db->aDb[] is much
+  ** more likely to cause a segfault than -1 (of course there are assert()
+  ** statements too, but it never hurts to play the odds) and
+  ** -32768 will still fit into a 16-bit signed integer.
+  */
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( pSchema ){
+    for(i=0; 1; i++){
+      assert( i<db->nDb );
+      if( db->aDb[i].pSchema==pSchema ){
+        break;
+      }
+    }
+    assert( i>=0 && i<db->nDb );
+  }
+  return i;
+}
+
+/*
+** Free all memory allocations in the pParse object
+*/
+SQLITE_PRIVATE void sqlite3ParseObjectReset(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  assert( db!=0 );
+  assert( db->pParse==pParse );
+  assert( pParse->nested==0 );
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  if( pParse->aTableLock ) sqlite3DbNNFreeNN(db, pParse->aTableLock);
+#endif
+  while( pParse->pCleanup ){
+    ParseCleanup *pCleanup = pParse->pCleanup;
+    pParse->pCleanup = pCleanup->pNext;
+    pCleanup->xCleanup(db, pCleanup->pPtr);
+    sqlite3DbNNFreeNN(db, pCleanup);
+  }
+  if( pParse->aLabel ) sqlite3DbNNFreeNN(db, pParse->aLabel);
+  if( pParse->pConstExpr ){
+    sqlite3ExprListDelete(db, pParse->pConstExpr);
+  }
+  assert( db->lookaside.bDisable >= pParse->disableLookaside );
+  db->lookaside.bDisable -= pParse->disableLookaside;
+  db->lookaside.sz = db->lookaside.bDisable ? 0 : db->lookaside.szTrue;
+  assert( pParse->db->pParse==pParse );
+  db->pParse = pParse->pOuterParse;
+}
+
+/*
+** Add a new cleanup operation to a Parser.  The cleanup should happen when
+** the parser object is destroyed.  But, beware: the cleanup might happen
+** immediately.
+**
+** Use this mechanism for uncommon cleanups.  There is a higher setup
+** cost for this mechanism (an extra malloc), so it should not be used
+** for common cleanups that happen on most calls.  But for less
+** common cleanups, we save a single NULL-pointer comparison in
+** sqlite3ParseObjectReset(), which reduces the total CPU cycle count.
+**
+** If a memory allocation error occurs, then the cleanup happens immediately.
+** When either SQLITE_DEBUG or SQLITE_COVERAGE_TEST are defined, the
+** pParse->earlyCleanup flag is set in that case.  Calling code show verify
+** that test cases exist for which this happens, to guard against possible
+** use-after-free errors following an OOM.  The preferred way to do this is
+** to immediately follow the call to this routine with:
+**
+**       testcase( pParse->earlyCleanup );
+**
+** This routine returns a copy of its pPtr input (the third parameter)
+** except if an early cleanup occurs, in which case it returns NULL.  So
+** another way to check for early cleanup is to check the return value.
+** Or, stop using the pPtr parameter with this call and use only its
+** return value thereafter.  Something like this:
+**
+**       pObj = sqlite3ParserAddCleanup(pParse, destructor, pObj);
+*/
+SQLITE_PRIVATE void *sqlite3ParserAddCleanup(
+  Parse *pParse,                      /* Destroy when this Parser finishes */
+  void (*xCleanup)(sqlite3*,void*),   /* The cleanup routine */
+  void *pPtr                          /* Pointer to object to be cleaned up */
+){
+  ParseCleanup *pCleanup;
+  if( sqlite3FaultSim(300) ){
+    pCleanup = 0;
+    sqlite3OomFault(pParse->db);
+  }else{
+    pCleanup = sqlite3DbMallocRaw(pParse->db, sizeof(*pCleanup));
+  }
+  if( pCleanup ){
+    pCleanup->pNext = pParse->pCleanup;
+    pParse->pCleanup = pCleanup;
+    pCleanup->pPtr = pPtr;
+    pCleanup->xCleanup = xCleanup;
+  }else{
+    xCleanup(pParse->db, pPtr);
+    pPtr = 0;
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+    pParse->earlyCleanup = 1;
+#endif
+  }
+  return pPtr;
+}
+
+/*
+** Turn bulk memory into a valid Parse object and link that Parse object
+** into database connection db.
+**
+** Call sqlite3ParseObjectReset() to undo this operation.
+**
+** Caution:  Do not confuse this routine with sqlite3ParseObjectInit() which
+** is generated by Lemon.
+*/
+SQLITE_PRIVATE void sqlite3ParseObjectInit(Parse *pParse, sqlite3 *db){
+  memset(PARSE_HDR(pParse), 0, PARSE_HDR_SZ);
+  memset(PARSE_TAIL(pParse), 0, PARSE_TAIL_SZ);
+  assert( db->pParse!=pParse );
+  pParse->pOuterParse = db->pParse;
+  db->pParse = pParse;
+  pParse->db = db;
+  if( db->mallocFailed ) sqlite3ErrorMsg(pParse, "out of memory");
+}
+
+/*
+** Maximum number of times that we will try again to prepare a statement
+** that returns SQLITE_ERROR_RETRY.
+*/
+#ifndef SQLITE_MAX_PREPARE_RETRY
+# define SQLITE_MAX_PREPARE_RETRY 25
+#endif
+
+/*
+** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
+*/
+static int sqlite3Prepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  u32 prepFlags,            /* Zero or more SQLITE_PREPARE_* flags */
+  Vdbe *pReprepare,         /* VM being reprepared */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc = SQLITE_OK;       /* Result code */
+  int i;                    /* Loop counter */
+  Parse sParse;             /* Parsing context */
+
+  /* sqlite3ParseObjectInit(&sParse, db); // inlined for performance */
+  memset(PARSE_HDR(&sParse), 0, PARSE_HDR_SZ);
+  memset(PARSE_TAIL(&sParse), 0, PARSE_TAIL_SZ);
+  sParse.pOuterParse = db->pParse;
+  db->pParse = &sParse;
+  sParse.db = db;
+  if( pReprepare ){
+    sParse.pReprepare = pReprepare;
+    sParse.explain = sqlite3_stmt_isexplain((sqlite3_stmt*)pReprepare);
+  }else{
+    assert( sParse.pReprepare==0 );
+  }
+  assert( ppStmt && *ppStmt==0 );
+  if( db->mallocFailed ){
+    sqlite3ErrorMsg(&sParse, "out of memory");
+    db->errCode = rc = SQLITE_NOMEM;
+    goto end_prepare;
+  }
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  /* For a long-term use prepared statement avoid the use of
+  ** lookaside memory.
+  */
+  if( prepFlags & SQLITE_PREPARE_PERSISTENT ){
+    sParse.disableLookaside++;
+    DisableLookaside;
+  }
+  sParse.prepFlags = prepFlags & 0xff;
+
+  /* Check to verify that it is possible to get a read lock on all
+  ** database schemas.  The inability to get a read lock indicates that
+  ** some other database connection is holding a write-lock, which in
+  ** turn means that the other connection has made uncommitted changes
+  ** to the schema.
+  **
+  ** Were we to proceed and prepare the statement against the uncommitted
+  ** schema changes and if those schema changes are subsequently rolled
+  ** back and different changes are made in their place, then when this
+  ** prepared statement goes to run the schema cookie would fail to detect
+  ** the schema change.  Disaster would follow.
+  **
+  ** This thread is currently holding mutexes on all Btrees (because
+  ** of the sqlite3BtreeEnterAll() in sqlite3LockAndPrepare()) so it
+  ** is not possible for another thread to start a new schema change
+  ** while this routine is running.  Hence, we do not need to hold
+  ** locks on the schema, we just need to make sure nobody else is
+  ** holding them.
+  **
+  ** Note that setting READ_UNCOMMITTED overrides most lock detection,
+  ** but it does *not* override schema lock detection, so this all still
+  ** works even if READ_UNCOMMITTED is set.
+  */
+  if( !db->noSharedCache ){
+    for(i=0; i<db->nDb; i++) {
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        assert( sqlite3BtreeHoldsMutex(pBt) );
+        rc = sqlite3BtreeSchemaLocked(pBt);
+        if( rc ){
+          const char *zDb = db->aDb[i].zDbSName;
+          sqlite3ErrorWithMsg(db, rc, "database schema is locked: %s", zDb);
+          testcase( db->flags & SQLITE_ReadUncommit );
+          goto end_prepare;
+        }
+      }
+    }
+  }
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( db->pDisconnect ) sqlite3VtabUnlockList(db);
+#endif
+
+  if( nBytes>=0 && (nBytes==0 || zSql[nBytes-1]!=0) ){
+    char *zSqlCopy;
+    int mxLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
+    testcase( nBytes==mxLen );
+    testcase( nBytes==mxLen+1 );
+    if( nBytes>mxLen ){
+      sqlite3ErrorWithMsg(db, SQLITE_TOOBIG, "statement too long");
+      rc = sqlite3ApiExit(db, SQLITE_TOOBIG);
+      goto end_prepare;
+    }
+    zSqlCopy = sqlite3DbStrNDup(db, zSql, nBytes);
+    if( zSqlCopy ){
+      sqlite3RunParser(&sParse, zSqlCopy);
+      sParse.zTail = &zSql[sParse.zTail-zSqlCopy];
+      sqlite3DbFree(db, zSqlCopy);
+    }else{
+      sParse.zTail = &zSql[nBytes];
+    }
+  }else{
+    sqlite3RunParser(&sParse, zSql);
+  }
+  assert( 0==sParse.nQueryLoop );
+
+  if( pzTail ){
+    *pzTail = sParse.zTail;
+  }
+
+  if( db->init.busy==0 ){
+    sqlite3VdbeSetSql(sParse.pVdbe, zSql, (int)(sParse.zTail-zSql), prepFlags);
+  }
+  if( db->mallocFailed ){
+    sParse.rc = SQLITE_NOMEM_BKPT;
+    sParse.checkSchema = 0;
+  }
+  if( sParse.rc!=SQLITE_OK && sParse.rc!=SQLITE_DONE ){
+    if( sParse.checkSchema && db->init.busy==0 ){
+      schemaIsValid(&sParse);
+    }
+    if( sParse.pVdbe ){
+      sqlite3VdbeFinalize(sParse.pVdbe);
+    }
+    assert( 0==(*ppStmt) );
+    rc = sParse.rc;
+    if( sParse.zErrMsg ){
+      sqlite3ErrorWithMsg(db, rc, "%s", sParse.zErrMsg);
+      sqlite3DbFree(db, sParse.zErrMsg);
+    }else{
+      sqlite3Error(db, rc);
+    }
+  }else{
+    assert( sParse.zErrMsg==0 );
+    *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
+    rc = SQLITE_OK;
+    sqlite3ErrorClear(db);
+  }
+
+
+  /* Delete any TriggerPrg structures allocated while parsing this statement. */
+  while( sParse.pTriggerPrg ){
+    TriggerPrg *pT = sParse.pTriggerPrg;
+    sParse.pTriggerPrg = pT->pNext;
+    sqlite3DbFree(db, pT);
+  }
+
+end_prepare:
+
+  sqlite3ParseObjectReset(&sParse);
+  return rc;
+}
+static int sqlite3LockAndPrepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  u32 prepFlags,            /* Zero or more SQLITE_PREPARE_* flags */
+  Vdbe *pOld,               /* VM being reprepared */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  int cnt = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppStmt==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *ppStmt = 0;
+  if( !sqlite3SafetyCheckOk(db)||zSql==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  do{
+    /* Make multiple attempts to compile the SQL, until it either succeeds
+    ** or encounters a permanent error.  A schema problem after one schema
+    ** reset is considered a permanent error. */
+    rc = sqlite3Prepare(db, zSql, nBytes, prepFlags, pOld, ppStmt, pzTail);
+    assert( rc==SQLITE_OK || *ppStmt==0 );
+    if( rc==SQLITE_OK || db->mallocFailed ) break;
+  }while( (rc==SQLITE_ERROR_RETRY && (cnt++)<SQLITE_MAX_PREPARE_RETRY)
+       || (rc==SQLITE_SCHEMA && (sqlite3ResetOneSchema(db,-1), cnt++)==0) );
+  sqlite3BtreeLeaveAll(db);
+  rc = sqlite3ApiExit(db, rc);
+  assert( (rc&db->errMask)==rc );
+  db->busyHandler.nBusy = 0;
+  sqlite3_mutex_leave(db->mutex);
+  assert( rc==SQLITE_OK || (*ppStmt)==0 );
+  return rc;
+}
+
+
+/*
+** Rerun the compilation of a statement after a schema change.
+**
+** If the statement is successfully recompiled, return SQLITE_OK. Otherwise,
+** if the statement cannot be recompiled because another connection has
+** locked the sqlite3_schema table, return SQLITE_LOCKED. If any other error
+** occurs, return SQLITE_SCHEMA.
+*/
+SQLITE_PRIVATE int sqlite3Reprepare(Vdbe *p){
+  int rc;
+  sqlite3_stmt *pNew;
+  const char *zSql;
+  sqlite3 *db;
+  u8 prepFlags;
+
+  assert( sqlite3_mutex_held(sqlite3VdbeDb(p)->mutex) );
+  zSql = sqlite3_sql((sqlite3_stmt *)p);
+  assert( zSql!=0 );  /* Reprepare only called for prepare_v2() statements */
+  db = sqlite3VdbeDb(p);
+  assert( sqlite3_mutex_held(db->mutex) );
+  prepFlags = sqlite3VdbePrepareFlags(p);
+  rc = sqlite3LockAndPrepare(db, zSql, -1, prepFlags, p, &pNew, 0);
+  if( rc ){
+    if( rc==SQLITE_NOMEM ){
+      sqlite3OomFault(db);
+    }
+    assert( pNew==0 );
+    return rc;
+  }else{
+    assert( pNew!=0 );
+  }
+  sqlite3VdbeSwap((Vdbe*)pNew, p);
+  sqlite3TransferBindings(pNew, (sqlite3_stmt*)p);
+  sqlite3VdbeResetStepResult((Vdbe*)pNew);
+  sqlite3VdbeFinalize((Vdbe*)pNew);
+  return SQLITE_OK;
+}
+
+
+/*
+** Two versions of the official API.  Legacy and new use.  In the legacy
+** version, the original SQL text is not saved in the prepared statement
+** and so if a schema change occurs, SQLITE_SCHEMA is returned by
+** sqlite3_step().  In the new version, the original SQL text is retained
+** and the statement is automatically recompiled if an schema change
+** occurs.
+*/
+SQLITE_API int sqlite3_prepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,0,0,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+SQLITE_API int sqlite3_prepare_v2(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  /* EVIDENCE-OF: R-37923-12173 The sqlite3_prepare_v2() interface works
+  ** exactly the same as sqlite3_prepare_v3() with a zero prepFlags
+  ** parameter.
+  **
+  ** Proof in that the 5th parameter to sqlite3LockAndPrepare is 0 */
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,SQLITE_PREPARE_SAVESQL,0,
+                             ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );
+  return rc;
+}
+SQLITE_API int sqlite3_prepare_v3(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  unsigned int prepFlags,   /* Zero or more SQLITE_PREPARE_* flags */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  /* EVIDENCE-OF: R-56861-42673 sqlite3_prepare_v3() differs from
+  ** sqlite3_prepare_v2() only in having the extra prepFlags parameter,
+  ** which is a bit array consisting of zero or more of the
+  ** SQLITE_PREPARE_* flags.
+  **
+  ** Proof by comparison to the implementation of sqlite3_prepare_v2()
+  ** directly above. */
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,
+                 SQLITE_PREPARE_SAVESQL|(prepFlags&SQLITE_PREPARE_MASK),
+                 0,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );
+  return rc;
+}
+
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Compile the UTF-16 encoded SQL statement zSql into a statement handle.
+*/
+static int sqlite3Prepare16(
+  sqlite3 *db,              /* Database handle. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  u32 prepFlags,            /* Zero or more SQLITE_PREPARE_* flags */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  /* This function currently works by first transforming the UTF-16
+  ** encoded string to UTF-8, then invoking sqlite3_prepare(). The
+  ** tricky bit is figuring out the pointer to return in *pzTail.
+  */
+  char *zSql8;
+  const char *zTail8 = 0;
+  int rc = SQLITE_OK;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppStmt==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *ppStmt = 0;
+  if( !sqlite3SafetyCheckOk(db)||zSql==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  /* Make sure nBytes is non-negative and correct.  It should be the
+  ** number of bytes until the end of the input buffer or until the first
+  ** U+0000 character.  If the input nBytes is odd, convert it into
+  ** an even number.  If the input nBytes is negative, then the input
+  ** must be terminated by at least one U+0000 character */
+  if( nBytes>=0 ){
+    int sz;
+    const char *z = (const char*)zSql;
+    for(sz=0; sz<nBytes && (z[sz]!=0 || z[sz+1]!=0); sz += 2){}
+    nBytes = sz;
+  }else{
+    int sz;
+    const char *z = (const char*)zSql;
+    for(sz=0; z[sz]!=0 || z[sz+1]!=0; sz += 2){}
+    nBytes = sz;
+  }
+
+  sqlite3_mutex_enter(db->mutex);
+  zSql8 = sqlite3Utf16to8(db, zSql, nBytes, SQLITE_UTF16NATIVE);
+  if( zSql8 ){
+    rc = sqlite3LockAndPrepare(db, zSql8, -1, prepFlags, 0, ppStmt, &zTail8);
+  }
+
+  if( zTail8 && pzTail ){
+    /* If sqlite3_prepare returns a tail pointer, we calculate the
+    ** equivalent pointer into the UTF-16 string by counting the unicode
+    ** characters between zSql8 and zTail8, and then returning a pointer
+    ** the same number of characters into the UTF-16 string.
+    */
+    int chars_parsed = sqlite3Utf8CharLen(zSql8, (int)(zTail8-zSql8));
+    *pzTail = (u8 *)zSql + sqlite3Utf16ByteLen(zSql, nBytes, chars_parsed);
+  }
+  sqlite3DbFree(db, zSql8);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Two versions of the official API.  Legacy and new use.  In the legacy
+** version, the original SQL text is not saved in the prepared statement
+** and so if a schema change occurs, SQLITE_SCHEMA is returned by
+** sqlite3_step().  In the new version, the original SQL text is retained
+** and the statement is automatically recompiled if an schema change
+** occurs.
+*/
+SQLITE_API int sqlite3_prepare16(
+  sqlite3 *db,              /* Database handle. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3Prepare16(db,zSql,nBytes,0,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+SQLITE_API int sqlite3_prepare16_v2(
+  sqlite3 *db,              /* Database handle. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3Prepare16(db,zSql,nBytes,SQLITE_PREPARE_SAVESQL,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+SQLITE_API int sqlite3_prepare16_v3(
+  sqlite3 *db,              /* Database handle. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  unsigned int prepFlags,   /* Zero or more SQLITE_PREPARE_* flags */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3Prepare16(db,zSql,nBytes,
+         SQLITE_PREPARE_SAVESQL|(prepFlags&SQLITE_PREPARE_MASK),
+         ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+
+#endif /* SQLITE_OMIT_UTF16 */
+
+/************** End of prepare.c *********************************************/
+/************** Begin file select.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle SELECT statements in SQLite.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** An instance of the following object is used to record information about
+** how to process the DISTINCT keyword, to simplify passing that information
+** into the selectInnerLoop() routine.
+*/
+typedef struct DistinctCtx DistinctCtx;
+struct DistinctCtx {
+  u8 isTnct;      /* 0: Not distinct. 1: DISTICT  2: DISTINCT and ORDER BY */
+  u8 eTnctType;   /* One of the WHERE_DISTINCT_* operators */
+  int tabTnct;    /* Ephemeral table used for DISTINCT processing */
+  int addrTnct;   /* Address of OP_OpenEphemeral opcode for tabTnct */
+};
+
+/*
+** An instance of the following object is used to record information about
+** the ORDER BY (or GROUP BY) clause of query is being coded.
+**
+** The aDefer[] array is used by the sorter-references optimization. For
+** example, assuming there is no index that can be used for the ORDER BY,
+** for the query:
+**
+**     SELECT a, bigblob FROM t1 ORDER BY a LIMIT 10;
+**
+** it may be more efficient to add just the "a" values to the sorter, and
+** retrieve the associated "bigblob" values directly from table t1 as the
+** 10 smallest "a" values are extracted from the sorter.
+**
+** When the sorter-reference optimization is used, there is one entry in the
+** aDefer[] array for each database table that may be read as values are
+** extracted from the sorter.
+*/
+typedef struct SortCtx SortCtx;
+struct SortCtx {
+  ExprList *pOrderBy;   /* The ORDER BY (or GROUP BY clause) */
+  int nOBSat;           /* Number of ORDER BY terms satisfied by indices */
+  int iECursor;         /* Cursor number for the sorter */
+  int regReturn;        /* Register holding block-output return address */
+  int labelBkOut;       /* Start label for the block-output subroutine */
+  int addrSortIndex;    /* Address of the OP_SorterOpen or OP_OpenEphemeral */
+  int labelDone;        /* Jump here when done, ex: LIMIT reached */
+  int labelOBLopt;      /* Jump here when sorter is full */
+  u8 sortFlags;         /* Zero or more SORTFLAG_* bits */
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  u8 nDefer;            /* Number of valid entries in aDefer[] */
+  struct DeferredCsr {
+    Table *pTab;        /* Table definition */
+    int iCsr;           /* Cursor number for table */
+    int nKey;           /* Number of PK columns for table pTab (>=1) */
+  } aDefer[4];
+#endif
+  struct RowLoadInfo *pDeferredRowLoad;  /* Deferred row loading info or NULL */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrPush;         /* First instruction to push data into sorter */
+  int addrPushEnd;      /* Last instruction that pushes data into sorter */
+#endif
+};
+#define SORTFLAG_UseSorter  0x01   /* Use SorterOpen instead of OpenEphemeral */
+
+/*
+** Delete all the content of a Select structure.  Deallocate the structure
+** itself depending on the value of bFree
+**
+** If bFree==1, call sqlite3DbFree() on the p object.
+** If bFree==0, Leave the first Select object unfreed
+*/
+static void clearSelect(sqlite3 *db, Select *p, int bFree){
+  assert( db!=0 );
+  while( p ){
+    Select *pPrior = p->pPrior;
+    sqlite3ExprListDelete(db, p->pEList);
+    sqlite3SrcListDelete(db, p->pSrc);
+    sqlite3ExprDelete(db, p->pWhere);
+    sqlite3ExprListDelete(db, p->pGroupBy);
+    sqlite3ExprDelete(db, p->pHaving);
+    sqlite3ExprListDelete(db, p->pOrderBy);
+    sqlite3ExprDelete(db, p->pLimit);
+    if( OK_IF_ALWAYS_TRUE(p->pWith) ) sqlite3WithDelete(db, p->pWith);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( OK_IF_ALWAYS_TRUE(p->pWinDefn) ){
+      sqlite3WindowListDelete(db, p->pWinDefn);
+    }
+    while( p->pWin ){
+      assert( p->pWin->ppThis==&p->pWin );
+      sqlite3WindowUnlinkFromSelect(p->pWin);
+    }
+#endif
+    if( bFree ) sqlite3DbNNFreeNN(db, p);
+    p = pPrior;
+    bFree = 1;
+  }
+}
+
+/*
+** Initialize a SelectDest structure.
+*/
+SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
+  pDest->eDest = (u8)eDest;
+  pDest->iSDParm = iParm;
+  pDest->iSDParm2 = 0;
+  pDest->zAffSdst = 0;
+  pDest->iSdst = 0;
+  pDest->nSdst = 0;
+}
+
+
+/*
+** Allocate a new Select structure and return a pointer to that
+** structure.
+*/
+SQLITE_PRIVATE Select *sqlite3SelectNew(
+  Parse *pParse,        /* Parsing context */
+  ExprList *pEList,     /* which columns to include in the result */
+  SrcList *pSrc,        /* the FROM clause -- which tables to scan */
+  Expr *pWhere,         /* the WHERE clause */
+  ExprList *pGroupBy,   /* the GROUP BY clause */
+  Expr *pHaving,        /* the HAVING clause */
+  ExprList *pOrderBy,   /* the ORDER BY clause */
+  u32 selFlags,         /* Flag parameters, such as SF_Distinct */
+  Expr *pLimit          /* LIMIT value.  NULL means not used */
+){
+  Select *pNew, *pAllocated;
+  Select standin;
+  pAllocated = pNew = sqlite3DbMallocRawNN(pParse->db, sizeof(*pNew) );
+  if( pNew==0 ){
+    assert( pParse->db->mallocFailed );
+    pNew = &standin;
+  }
+  if( pEList==0 ){
+    pEList = sqlite3ExprListAppend(pParse, 0,
+                                   sqlite3Expr(pParse->db,TK_ASTERISK,0));
+  }
+  pNew->pEList = pEList;
+  pNew->op = TK_SELECT;
+  pNew->selFlags = selFlags;
+  pNew->iLimit = 0;
+  pNew->iOffset = 0;
+  pNew->selId = ++pParse->nSelect;
+  pNew->addrOpenEphm[0] = -1;
+  pNew->addrOpenEphm[1] = -1;
+  pNew->nSelectRow = 0;
+  if( pSrc==0 ) pSrc = sqlite3DbMallocZero(pParse->db, sizeof(*pSrc));
+  pNew->pSrc = pSrc;
+  pNew->pWhere = pWhere;
+  pNew->pGroupBy = pGroupBy;
+  pNew->pHaving = pHaving;
+  pNew->pOrderBy = pOrderBy;
+  pNew->pPrior = 0;
+  pNew->pNext = 0;
+  pNew->pLimit = pLimit;
+  pNew->pWith = 0;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  pNew->pWin = 0;
+  pNew->pWinDefn = 0;
+#endif
+  if( pParse->db->mallocFailed ) {
+    clearSelect(pParse->db, pNew, pNew!=&standin);
+    pAllocated = 0;
+  }else{
+    assert( pNew->pSrc!=0 || pParse->nErr>0 );
+  }
+  return pAllocated;
+}
+
+
+/*
+** Delete the given Select structure and all of its substructures.
+*/
+SQLITE_PRIVATE void sqlite3SelectDelete(sqlite3 *db, Select *p){
+  if( OK_IF_ALWAYS_TRUE(p) ) clearSelect(db, p, 1);
+}
+SQLITE_PRIVATE void sqlite3SelectDeleteGeneric(sqlite3 *db, void *p){
+  if( ALWAYS(p) ) clearSelect(db, (Select*)p, 1);
+}
+
+/*
+** Return a pointer to the right-most SELECT statement in a compound.
+*/
+static Select *findRightmost(Select *p){
+  while( p->pNext ) p = p->pNext;
+  return p;
+}
+
+/*
+** Given 1 to 3 identifiers preceding the JOIN keyword, determine the
+** type of join.  Return an integer constant that expresses that type
+** in terms of the following bit values:
+**
+**     JT_INNER
+**     JT_CROSS
+**     JT_OUTER
+**     JT_NATURAL
+**     JT_LEFT
+**     JT_RIGHT
+**
+** A full outer join is the combination of JT_LEFT and JT_RIGHT.
+**
+** If an illegal or unsupported join type is seen, then still return
+** a join type, but put an error in the pParse structure.
+**
+** These are the valid join types:
+**
+**
+**      pA       pB       pC               Return Value
+**     -------  -----    -----             ------------
+**     CROSS      -        -                 JT_CROSS
+**     INNER      -        -                 JT_INNER
+**     LEFT       -        -                 JT_LEFT|JT_OUTER
+**     LEFT     OUTER      -                 JT_LEFT|JT_OUTER
+**     RIGHT      -        -                 JT_RIGHT|JT_OUTER
+**     RIGHT    OUTER      -                 JT_RIGHT|JT_OUTER
+**     FULL       -        -                 JT_LEFT|JT_RIGHT|JT_OUTER
+**     FULL     OUTER      -                 JT_LEFT|JT_RIGHT|JT_OUTER
+**     NATURAL  INNER      -                 JT_NATURAL|JT_INNER
+**     NATURAL  LEFT       -                 JT_NATURAL|JT_LEFT|JT_OUTER
+**     NATURAL  LEFT     OUTER               JT_NATURAL|JT_LEFT|JT_OUTER
+**     NATURAL  RIGHT      -                 JT_NATURAL|JT_RIGHT|JT_OUTER
+**     NATURAL  RIGHT    OUTER               JT_NATURAL|JT_RIGHT|JT_OUTER
+**     NATURAL  FULL       -                 JT_NATURAL|JT_LEFT|JT_RIGHT
+**     NATURAL  FULL     OUTER               JT_NATRUAL|JT_LEFT|JT_RIGHT
+**
+** To preserve historical compatibly, SQLite also accepts a variety
+** of other non-standard and in many cases nonsensical join types.
+** This routine makes as much sense at it can from the nonsense join
+** type and returns a result.  Examples of accepted nonsense join types
+** include but are not limited to:
+**
+**          INNER CROSS JOIN        ->   same as JOIN
+**          NATURAL CROSS JOIN      ->   same as NATURAL JOIN
+**          OUTER LEFT JOIN         ->   same as LEFT JOIN
+**          LEFT NATURAL JOIN       ->   same as NATURAL LEFT JOIN
+**          LEFT RIGHT JOIN         ->   same as FULL JOIN
+**          RIGHT OUTER FULL JOIN   ->   same as FULL JOIN
+**          CROSS CROSS CROSS JOIN  ->   same as JOIN
+**
+** The only restrictions on the join type name are:
+**
+**    *   "INNER" cannot appear together with "OUTER", "LEFT", "RIGHT",
+**        or "FULL".
+**
+**    *   "CROSS" cannot appear together with "OUTER", "LEFT", "RIGHT,
+**        or "FULL".
+**
+**    *   If "OUTER" is present then there must also be one of
+**        "LEFT", "RIGHT", or "FULL"
+*/
+SQLITE_PRIVATE int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
+  int jointype = 0;
+  Token *apAll[3];
+  Token *p;
+                             /*   0123456789 123456789 123456789 123 */
+  static const char zKeyText[] = "naturaleftouterightfullinnercross";
+  static const struct {
+    u8 i;        /* Beginning of keyword text in zKeyText[] */
+    u8 nChar;    /* Length of the keyword in characters */
+    u8 code;     /* Join type mask */
+  } aKeyword[] = {
+    /* (0) natural */ { 0,  7, JT_NATURAL                },
+    /* (1) left    */ { 6,  4, JT_LEFT|JT_OUTER          },
+    /* (2) outer   */ { 10, 5, JT_OUTER                  },
+    /* (3) right   */ { 14, 5, JT_RIGHT|JT_OUTER         },
+    /* (4) full    */ { 19, 4, JT_LEFT|JT_RIGHT|JT_OUTER },
+    /* (5) inner   */ { 23, 5, JT_INNER                  },
+    /* (6) cross   */ { 28, 5, JT_INNER|JT_CROSS         },
+  };
+  int i, j;
+  apAll[0] = pA;
+  apAll[1] = pB;
+  apAll[2] = pC;
+  for(i=0; i<3 && apAll[i]; i++){
+    p = apAll[i];
+    for(j=0; j<ArraySize(aKeyword); j++){
+      if( p->n==aKeyword[j].nChar
+          && sqlite3StrNICmp((char*)p->z, &zKeyText[aKeyword[j].i], p->n)==0 ){
+        jointype |= aKeyword[j].code;
+        break;
+      }
+    }
+    testcase( j==0 || j==1 || j==2 || j==3 || j==4 || j==5 || j==6 );
+    if( j>=ArraySize(aKeyword) ){
+      jointype |= JT_ERROR;
+      break;
+    }
+  }
+  if(
+     (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
+     (jointype & JT_ERROR)!=0 ||
+     (jointype & (JT_OUTER|JT_LEFT|JT_RIGHT))==JT_OUTER
+  ){
+    const char *zSp1 = " ";
+    const char *zSp2 = " ";
+    if( pB==0 ){ zSp1++; }
+    if( pC==0 ){ zSp2++; }
+    sqlite3ErrorMsg(pParse, "unknown join type: "
+       "%T%s%T%s%T", pA, zSp1, pB, zSp2, pC);
+    jointype = JT_INNER;
+  }
+  return jointype;
+}
+
+/*
+** Return the index of a column in a table.  Return -1 if the column
+** is not contained in the table.
+*/
+SQLITE_PRIVATE int sqlite3ColumnIndex(Table *pTab, const char *zCol){
+  int i;
+  u8 h = sqlite3StrIHash(zCol);
+  Column *pCol;
+  for(pCol=pTab->aCol, i=0; i<pTab->nCol; pCol++, i++){
+    if( pCol->hName==h && sqlite3StrICmp(pCol->zCnName, zCol)==0 ) return i;
+  }
+  return -1;
+}
+
+/*
+** Mark a subquery result column as having been used.
+*/
+SQLITE_PRIVATE void sqlite3SrcItemColumnUsed(SrcItem *pItem, int iCol){
+  assert( pItem!=0 );
+  assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem) );
+  if( pItem->fg.isNestedFrom ){
+    ExprList *pResults;
+    assert( pItem->fg.isSubquery );
+    assert( pItem->u4.pSubq!=0 );
+    assert( pItem->u4.pSubq->pSelect!=0 );
+    pResults = pItem->u4.pSubq->pSelect->pEList;
+    assert( pResults!=0 );
+    assert( iCol>=0 && iCol<pResults->nExpr );
+    pResults->a[iCol].fg.bUsed = 1;
+  }
+}
+
+/*
+** Search the tables iStart..iEnd (inclusive) in pSrc, looking for a
+** table that has a column named zCol.  The search is left-to-right.
+** The first match found is returned.
+**
+** When found, set *piTab and *piCol to the table index and column index
+** of the matching column and return TRUE.
+**
+** If not found, return FALSE.
+*/
+static int tableAndColumnIndex(
+  SrcList *pSrc,       /* Array of tables to search */
+  int iStart,          /* First member of pSrc->a[] to check */
+  int iEnd,            /* Last member of pSrc->a[] to check */
+  const char *zCol,    /* Name of the column we are looking for */
+  int *piTab,          /* Write index of pSrc->a[] here */
+  int *piCol,          /* Write index of pSrc->a[*piTab].pTab->aCol[] here */
+  int bIgnoreHidden    /* Ignore hidden columns */
+){
+  int i;               /* For looping over tables in pSrc */
+  int iCol;            /* Index of column matching zCol */
+
+  assert( iEnd<pSrc->nSrc );
+  assert( iStart>=0 );
+  assert( (piTab==0)==(piCol==0) );  /* Both or neither are NULL */
+
+  for(i=iStart; i<=iEnd; i++){
+    iCol = sqlite3ColumnIndex(pSrc->a[i].pSTab, zCol);
+    if( iCol>=0
+     && (bIgnoreHidden==0 || IsHiddenColumn(&pSrc->a[i].pSTab->aCol[iCol])==0)
+    ){
+      if( piTab ){
+        sqlite3SrcItemColumnUsed(&pSrc->a[i], iCol);
+        *piTab = i;
+        *piCol = iCol;
+      }
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Set the EP_OuterON property on all terms of the given expression.
+** And set the Expr.w.iJoin to iTable for every term in the
+** expression.
+**
+** The EP_OuterON property is used on terms of an expression to tell
+** the OUTER JOIN processing logic that this term is part of the
+** join restriction specified in the ON or USING clause and not a part
+** of the more general WHERE clause.  These terms are moved over to the
+** WHERE clause during join processing but we need to remember that they
+** originated in the ON or USING clause.
+**
+** The Expr.w.iJoin tells the WHERE clause processing that the
+** expression depends on table w.iJoin even if that table is not
+** explicitly mentioned in the expression.  That information is needed
+** for cases like this:
+**
+**    SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
+**
+** The where clause needs to defer the handling of the t1.x=5
+** term until after the t2 loop of the join.  In that way, a
+** NULL t2 row will be inserted whenever t1.x!=5.  If we do not
+** defer the handling of t1.x=5, it will be processed immediately
+** after the t1 loop and rows with t1.x!=5 will never appear in
+** the output, which is incorrect.
+*/
+SQLITE_PRIVATE void sqlite3SetJoinExpr(Expr *p, int iTable, u32 joinFlag){
+  assert( joinFlag==EP_OuterON || joinFlag==EP_InnerON );
+  while( p ){
+    ExprSetProperty(p, joinFlag);
+    assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
+    ExprSetVVAProperty(p, EP_NoReduce);
+    p->w.iJoin = iTable;
+    if( p->op==TK_FUNCTION ){
+      assert( ExprUseXList(p) );
+      if( p->x.pList ){
+        int i;
+        for(i=0; i<p->x.pList->nExpr; i++){
+          sqlite3SetJoinExpr(p->x.pList->a[i].pExpr, iTable, joinFlag);
+        }
+      }
+    }
+    sqlite3SetJoinExpr(p->pLeft, iTable, joinFlag);
+    p = p->pRight;
+  }
+}
+
+/* Undo the work of sqlite3SetJoinExpr().  This is used when a LEFT JOIN
+** is simplified into an ordinary JOIN, and when an ON expression is
+** "pushed down" into the WHERE clause of a subquery.
+**
+** Convert every term that is marked with EP_OuterON and w.iJoin==iTable into
+** an ordinary term that omits the EP_OuterON mark.  Or if iTable<0, then
+** just clear every EP_OuterON and EP_InnerON mark from the expression tree.
+**
+** If nullable is true, that means that Expr p might evaluate to NULL even
+** if it is a reference to a NOT NULL column.  This can happen, for example,
+** if the table that p references is on the left side of a RIGHT JOIN.
+** If nullable is true, then take care to not remove the EP_CanBeNull bit.
+** See forum thread https://sqlite.org/forum/forumpost/b40696f50145d21c
+*/
+static void unsetJoinExpr(Expr *p, int iTable, int nullable){
+  while( p ){
+    if( iTable<0 || (ExprHasProperty(p, EP_OuterON) && p->w.iJoin==iTable) ){
+      ExprClearProperty(p, EP_OuterON|EP_InnerON);
+      if( iTable>=0 ) ExprSetProperty(p, EP_InnerON);
+    }
+    if( p->op==TK_COLUMN && p->iTable==iTable && !nullable ){
+      ExprClearProperty(p, EP_CanBeNull);
+    }
+    if( p->op==TK_FUNCTION ){
+      assert( ExprUseXList(p) );
+      assert( p->pLeft==0 );
+      if( p->x.pList ){
+        int i;
+        for(i=0; i<p->x.pList->nExpr; i++){
+          unsetJoinExpr(p->x.pList->a[i].pExpr, iTable, nullable);
+        }
+      }
+    }
+    unsetJoinExpr(p->pLeft, iTable, nullable);
+    p = p->pRight;
+  }
+}
+
+/*
+** This routine processes the join information for a SELECT statement.
+**
+**   *  A NATURAL join is converted into a USING join.  After that, we
+**      do not need to be concerned with NATURAL joins and we only have
+**      think about USING joins.
+**
+**   *  ON and USING clauses result in extra terms being added to the
+**      WHERE clause to enforce the specified constraints.  The extra
+**      WHERE clause terms will be tagged with EP_OuterON or
+**      EP_InnerON so that we know that they originated in ON/USING.
+**
+** The terms of a FROM clause are contained in the Select.pSrc structure.
+** The left most table is the first entry in Select.pSrc.  The right-most
+** table is the last entry.  The join operator is held in the entry to
+** the right.  Thus entry 1 contains the join operator for the join between
+** entries 0 and 1.  Any ON or USING clauses associated with the join are
+** also attached to the right entry.
+**
+** This routine returns the number of errors encountered.
+*/
+static int sqlite3ProcessJoin(Parse *pParse, Select *p){
+  SrcList *pSrc;                  /* All tables in the FROM clause */
+  int i, j;                       /* Loop counters */
+  SrcItem *pLeft;                 /* Left table being joined */
+  SrcItem *pRight;                /* Right table being joined */
+
+  pSrc = p->pSrc;
+  pLeft = &pSrc->a[0];
+  pRight = &pLeft[1];
+  for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
+    Table *pRightTab = pRight->pSTab;
+    u32 joinType;
+
+    if( NEVER(pLeft->pSTab==0 || pRightTab==0) ) continue;
+    joinType = (pRight->fg.jointype & JT_OUTER)!=0 ? EP_OuterON : EP_InnerON;
+
+    /* If this is a NATURAL join, synthesize an appropriate USING clause
+    ** to specify which columns should be joined.
+    */
+    if( pRight->fg.jointype & JT_NATURAL ){
+      IdList *pUsing = 0;
+      if( pRight->fg.isUsing || pRight->u3.pOn ){
+        sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
+           "an ON or USING clause", 0);
+        return 1;
+      }
+      for(j=0; j<pRightTab->nCol; j++){
+        char *zName;   /* Name of column in the right table */
+
+        if( IsHiddenColumn(&pRightTab->aCol[j]) ) continue;
+        zName = pRightTab->aCol[j].zCnName;
+        if( tableAndColumnIndex(pSrc, 0, i, zName, 0, 0, 1) ){
+          pUsing = sqlite3IdListAppend(pParse, pUsing, 0);
+          if( pUsing ){
+            assert( pUsing->nId>0 );
+            assert( pUsing->a[pUsing->nId-1].zName==0 );
+            pUsing->a[pUsing->nId-1].zName = sqlite3DbStrDup(pParse->db, zName);
+          }
+        }
+      }
+      if( pUsing ){
+        pRight->fg.isUsing = 1;
+        pRight->fg.isSynthUsing = 1;
+        pRight->u3.pUsing = pUsing;
+      }
+      if( pParse->nErr ) return 1;
+    }
+
+    /* Create extra terms on the WHERE clause for each column named
+    ** in the USING clause.  Example: If the two tables to be joined are
+    ** A and B and the USING clause names X, Y, and Z, then add this
+    ** to the WHERE clause:    A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
+    ** Report an error if any column mentioned in the USING clause is
+    ** not contained in both tables to be joined.
+    */
+    if( pRight->fg.isUsing ){
+      IdList *pList = pRight->u3.pUsing;
+      sqlite3 *db = pParse->db;
+      assert( pList!=0 );
+      for(j=0; j<pList->nId; j++){
+        char *zName;     /* Name of the term in the USING clause */
+        int iLeft;       /* Table on the left with matching column name */
+        int iLeftCol;    /* Column number of matching column on the left */
+        int iRightCol;   /* Column number of matching column on the right */
+        Expr *pE1;       /* Reference to the column on the LEFT of the join */
+        Expr *pE2;       /* Reference to the column on the RIGHT of the join */
+        Expr *pEq;       /* Equality constraint.  pE1 == pE2 */
+
+        zName = pList->a[j].zName;
+        iRightCol = sqlite3ColumnIndex(pRightTab, zName);
+        if( iRightCol<0
+         || tableAndColumnIndex(pSrc, 0, i, zName, &iLeft, &iLeftCol,
+                                pRight->fg.isSynthUsing)==0
+        ){
+          sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
+            "not present in both tables", zName);
+          return 1;
+        }
+        pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol);
+        sqlite3SrcItemColumnUsed(&pSrc->a[iLeft], iLeftCol);
+        if( (pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
+          /* This branch runs if the query contains one or more RIGHT or FULL
+          ** JOINs.  If only a single table on the left side of this join
+          ** contains the zName column, then this branch is a no-op.
+          ** But if there are two or more tables on the left side
+          ** of the join, construct a coalesce() function that gathers all
+          ** such tables.  Raise an error if more than one of those references
+          ** to zName is not also within a prior USING clause.
+          **
+          ** We really ought to raise an error if there are two or more
+          ** non-USING references to zName on the left of an INNER or LEFT
+          ** JOIN.  But older versions of SQLite do not do that, so we avoid
+          ** adding a new error so as to not break legacy applications.
+          */
+          ExprList *pFuncArgs = 0;   /* Arguments to the coalesce() */
+          static const Token tkCoalesce = { "coalesce", 8 };
+          while( tableAndColumnIndex(pSrc, iLeft+1, i, zName, &iLeft, &iLeftCol,
+                                     pRight->fg.isSynthUsing)!=0 ){
+            if( pSrc->a[iLeft].fg.isUsing==0
+             || sqlite3IdListIndex(pSrc->a[iLeft].u3.pUsing, zName)<0
+            ){
+              sqlite3ErrorMsg(pParse, "ambiguous reference to %s in USING()",
+                              zName);
+              break;
+            }
+            pFuncArgs = sqlite3ExprListAppend(pParse, pFuncArgs, pE1);
+            pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol);
+            sqlite3SrcItemColumnUsed(&pSrc->a[iLeft], iLeftCol);
+          }
+          if( pFuncArgs ){
+            pFuncArgs = sqlite3ExprListAppend(pParse, pFuncArgs, pE1);
+            pE1 = sqlite3ExprFunction(pParse, pFuncArgs, &tkCoalesce, 0);
+          }
+        }
+        pE2 = sqlite3CreateColumnExpr(db, pSrc, i+1, iRightCol);
+        sqlite3SrcItemColumnUsed(pRight, iRightCol);
+        pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2);
+        assert( pE2!=0 || pEq==0 );
+        if( pEq ){
+          ExprSetProperty(pEq, joinType);
+          assert( !ExprHasProperty(pEq, EP_TokenOnly|EP_Reduced) );
+          ExprSetVVAProperty(pEq, EP_NoReduce);
+          pEq->w.iJoin = pE2->iTable;
+        }
+        p->pWhere = sqlite3ExprAnd(pParse, p->pWhere, pEq);
+      }
+    }
+
+    /* Add the ON clause to the end of the WHERE clause, connected by
+    ** an AND operator.
+    */
+    else if( pRight->u3.pOn ){
+      sqlite3SetJoinExpr(pRight->u3.pOn, pRight->iCursor, joinType);
+      p->pWhere = sqlite3ExprAnd(pParse, p->pWhere, pRight->u3.pOn);
+      pRight->u3.pOn = 0;
+      pRight->fg.isOn = 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** An instance of this object holds information (beyond pParse and pSelect)
+** needed to load the next result row that is to be added to the sorter.
+*/
+typedef struct RowLoadInfo RowLoadInfo;
+struct RowLoadInfo {
+  int regResult;               /* Store results in array of registers here */
+  u8 ecelFlags;                /* Flag argument to ExprCodeExprList() */
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  ExprList *pExtra;            /* Extra columns needed by sorter refs */
+  int regExtraResult;          /* Where to load the extra columns */
+#endif
+};
+
+/*
+** This routine does the work of loading query data into an array of
+** registers so that it can be added to the sorter.
+*/
+static void innerLoopLoadRow(
+  Parse *pParse,             /* Statement under construction */
+  Select *pSelect,           /* The query being coded */
+  RowLoadInfo *pInfo         /* Info needed to complete the row load */
+){
+  sqlite3ExprCodeExprList(pParse, pSelect->pEList, pInfo->regResult,
+                          0, pInfo->ecelFlags);
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  if( pInfo->pExtra ){
+    sqlite3ExprCodeExprList(pParse, pInfo->pExtra, pInfo->regExtraResult, 0, 0);
+    sqlite3ExprListDelete(pParse->db, pInfo->pExtra);
+  }
+#endif
+}
+
+/*
+** Code the OP_MakeRecord instruction that generates the entry to be
+** added into the sorter.
+**
+** Return the register in which the result is stored.
+*/
+static int makeSorterRecord(
+  Parse *pParse,
+  SortCtx *pSort,
+  Select *pSelect,
+  int regBase,
+  int nBase
+){
+  int nOBSat = pSort->nOBSat;
+  Vdbe *v = pParse->pVdbe;
+  int regOut = ++pParse->nMem;
+  if( pSort->pDeferredRowLoad ){
+    innerLoopLoadRow(pParse, pSelect, pSort->pDeferredRowLoad);
+  }
+  sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase+nOBSat, nBase-nOBSat, regOut);
+  return regOut;
+}
+
+/*
+** Generate code that will push the record in registers regData
+** through regData+nData-1 onto the sorter.
+*/
+static void pushOntoSorter(
+  Parse *pParse,         /* Parser context */
+  SortCtx *pSort,        /* Information about the ORDER BY clause */
+  Select *pSelect,       /* The whole SELECT statement */
+  int regData,           /* First register holding data to be sorted */
+  int regOrigData,       /* First register holding data before packing */
+  int nData,             /* Number of elements in the regData data array */
+  int nPrefixReg         /* No. of reg prior to regData available for use */
+){
+  Vdbe *v = pParse->pVdbe;                         /* Stmt under construction */
+  int bSeq = ((pSort->sortFlags & SORTFLAG_UseSorter)==0);
+  int nExpr = pSort->pOrderBy->nExpr;              /* No. of ORDER BY terms */
+  int nBase = nExpr + bSeq + nData;                /* Fields in sorter record */
+  int regBase;                                     /* Regs for sorter record */
+  int regRecord = 0;                               /* Assembled sorter record */
+  int nOBSat = pSort->nOBSat;                      /* ORDER BY terms to skip */
+  int op;                            /* Opcode to add sorter record to sorter */
+  int iLimit;                        /* LIMIT counter */
+  int iSkip = 0;                     /* End of the sorter insert loop */
+
+  assert( bSeq==0 || bSeq==1 );
+
+  /* Three cases:
+  **   (1) The data to be sorted has already been packed into a Record
+  **       by a prior OP_MakeRecord.  In this case nData==1 and regData
+  **       will be completely unrelated to regOrigData.
+  **   (2) All output columns are included in the sort record.  In that
+  **       case regData==regOrigData.
+  **   (3) Some output columns are omitted from the sort record due to
+  **       the SQLITE_ENABLE_SORTER_REFERENCES optimization, or due to the
+  **       SQLITE_ECEL_OMITREF optimization, or due to the
+  **       SortCtx.pDeferredRowLoad optimization.  In any of these cases
+  **       regOrigData is 0 to prevent this routine from trying to copy
+  **       values that might not yet exist.
+  */
+  assert( nData==1 || regData==regOrigData || regOrigData==0 );
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  pSort->addrPush = sqlite3VdbeCurrentAddr(v);
+#endif
+
+  if( nPrefixReg ){
+    assert( nPrefixReg==nExpr+bSeq );
+    regBase = regData - nPrefixReg;
+  }else{
+    regBase = pParse->nMem + 1;
+    pParse->nMem += nBase;
+  }
+  assert( pSelect->iOffset==0 || pSelect->iLimit!=0 );
+  iLimit = pSelect->iOffset ? pSelect->iOffset+1 : pSelect->iLimit;
+  pSort->labelDone = sqlite3VdbeMakeLabel(pParse);
+  sqlite3ExprCodeExprList(pParse, pSort->pOrderBy, regBase, regOrigData,
+                          SQLITE_ECEL_DUP | (regOrigData? SQLITE_ECEL_REF : 0));
+  if( bSeq ){
+    sqlite3VdbeAddOp2(v, OP_Sequence, pSort->iECursor, regBase+nExpr);
+  }
+  if( nPrefixReg==0 && nData>0 ){
+    sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+bSeq, nData);
+  }
+  if( nOBSat>0 ){
+    int regPrevKey;   /* The first nOBSat columns of the previous row */
+    int addrFirst;    /* Address of the OP_IfNot opcode */
+    int addrJmp;      /* Address of the OP_Jump opcode */
+    VdbeOp *pOp;      /* Opcode that opens the sorter */
+    int nKey;         /* Number of sorting key columns, including OP_Sequence */
+    KeyInfo *pKI;     /* Original KeyInfo on the sorter table */
+
+    regRecord = makeSorterRecord(pParse, pSort, pSelect, regBase, nBase);
+    regPrevKey = pParse->nMem+1;
+    pParse->nMem += pSort->nOBSat;
+    nKey = nExpr - pSort->nOBSat + bSeq;
+    if( bSeq ){
+      addrFirst = sqlite3VdbeAddOp1(v, OP_IfNot, regBase+nExpr);
+    }else{
+      addrFirst = sqlite3VdbeAddOp1(v, OP_SequenceTest, pSort->iECursor);
+    }
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp3(v, OP_Compare, regPrevKey, regBase, pSort->nOBSat);
+    pOp = sqlite3VdbeGetOp(v, pSort->addrSortIndex);
+    if( pParse->db->mallocFailed ) return;
+    pOp->p2 = nKey + nData;
+    pKI = pOp->p4.pKeyInfo;
+    memset(pKI->aSortFlags, 0, pKI->nKeyField); /* Makes OP_Jump testable */
+    sqlite3VdbeChangeP4(v, -1, (char*)pKI, P4_KEYINFO);
+    testcase( pKI->nAllField > pKI->nKeyField+2 );
+    pOp->p4.pKeyInfo = sqlite3KeyInfoFromExprList(pParse,pSort->pOrderBy,nOBSat,
+                                           pKI->nAllField-pKI->nKeyField-1);
+    pOp = 0; /* Ensure pOp not used after sqlite3VdbeAddOp3() */
+    addrJmp = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeAddOp3(v, OP_Jump, addrJmp+1, 0, addrJmp+1); VdbeCoverage(v);
+    pSort->labelBkOut = sqlite3VdbeMakeLabel(pParse);
+    pSort->regReturn = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Gosub, pSort->regReturn, pSort->labelBkOut);
+    sqlite3VdbeAddOp1(v, OP_ResetSorter, pSort->iECursor);
+    if( iLimit ){
+      sqlite3VdbeAddOp2(v, OP_IfNot, iLimit, pSort->labelDone);
+      VdbeCoverage(v);
+    }
+    sqlite3VdbeJumpHere(v, addrFirst);
+    sqlite3ExprCodeMove(pParse, regBase, regPrevKey, pSort->nOBSat);
+    sqlite3VdbeJumpHere(v, addrJmp);
+  }
+  if( iLimit ){
+    /* At this point the values for the new sorter entry are stored
+    ** in an array of registers. They need to be composed into a record
+    ** and inserted into the sorter if either (a) there are currently
+    ** less than LIMIT+OFFSET items or (b) the new record is smaller than
+    ** the largest record currently in the sorter. If (b) is true and there
+    ** are already LIMIT+OFFSET items in the sorter, delete the largest
+    ** entry before inserting the new one. This way there are never more
+    ** than LIMIT+OFFSET items in the sorter.
+    **
+    ** If the new record does not need to be inserted into the sorter,
+    ** jump to the next iteration of the loop. If the pSort->labelOBLopt
+    ** value is not zero, then it is a label of where to jump.  Otherwise,
+    ** just bypass the row insert logic.  See the header comment on the
+    ** sqlite3WhereOrderByLimitOptLabel() function for additional info.
+    */
+    int iCsr = pSort->iECursor;
+    sqlite3VdbeAddOp2(v, OP_IfNotZero, iLimit, sqlite3VdbeCurrentAddr(v)+4);
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp2(v, OP_Last, iCsr, 0);
+    iSkip = sqlite3VdbeAddOp4Int(v, OP_IdxLE,
+                                 iCsr, 0, regBase+nOBSat, nExpr-nOBSat);
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp1(v, OP_Delete, iCsr);
+  }
+  if( regRecord==0 ){
+    regRecord = makeSorterRecord(pParse, pSort, pSelect, regBase, nBase);
+  }
+  if( pSort->sortFlags & SORTFLAG_UseSorter ){
+    op = OP_SorterInsert;
+  }else{
+    op = OP_IdxInsert;
+  }
+  sqlite3VdbeAddOp4Int(v, op, pSort->iECursor, regRecord,
+                       regBase+nOBSat, nBase-nOBSat);
+  if( iSkip ){
+    sqlite3VdbeChangeP2(v, iSkip,
+         pSort->labelOBLopt ? pSort->labelOBLopt : sqlite3VdbeCurrentAddr(v));
+  }
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  pSort->addrPushEnd = sqlite3VdbeCurrentAddr(v)-1;
+#endif
+}
+
+/*
+** Add code to implement the OFFSET
+*/
+static void codeOffset(
+  Vdbe *v,          /* Generate code into this VM */
+  int iOffset,      /* Register holding the offset counter */
+  int iContinue     /* Jump here to skip the current record */
+){
+  if( iOffset>0 ){
+    sqlite3VdbeAddOp3(v, OP_IfPos, iOffset, iContinue, 1); VdbeCoverage(v);
+    VdbeComment((v, "OFFSET"));
+  }
+}
+
+/*
+** Add code that will check to make sure the array of registers starting at
+** iMem form a distinct entry. This is used by both "SELECT DISTINCT ..." and
+** distinct aggregates ("SELECT count(DISTINCT <expr>) ..."). Three strategies
+** are available. Which is used depends on the value of parameter eTnctType,
+** as follows:
+**
+**   WHERE_DISTINCT_UNORDERED/WHERE_DISTINCT_NOOP:
+**     Build an ephemeral table that contains all entries seen before and
+**     skip entries which have been seen before.
+**
+**     Parameter iTab is the cursor number of an ephemeral table that must
+**     be opened before the VM code generated by this routine is executed.
+**     The ephemeral cursor table is queried for a record identical to the
+**     record formed by the current array of registers. If one is found,
+**     jump to VM address addrRepeat. Otherwise, insert a new record into
+**     the ephemeral cursor and proceed.
+**
+**     The returned value in this case is a copy of parameter iTab.
+**
+**   WHERE_DISTINCT_ORDERED:
+**     In this case rows are being delivered sorted order. The ephemeral
+**     table is not required. Instead, the current set of values
+**     is compared against previous row. If they match, the new row
+**     is not distinct and control jumps to VM address addrRepeat. Otherwise,
+**     the VM program proceeds with processing the new row.
+**
+**     The returned value in this case is the register number of the first
+**     in an array of registers used to store the previous result row so that
+**     it can be compared to the next. The caller must ensure that this
+**     register is initialized to NULL.  (The fixDistinctOpenEph() routine
+**     will take care of this initialization.)
+**
+**   WHERE_DISTINCT_UNIQUE:
+**     In this case it has already been determined that the rows are distinct.
+**     No special action is required. The return value is zero.
+**
+** Parameter pEList is the list of expressions used to generated the
+** contents of each row. It is used by this routine to determine (a)
+** how many elements there are in the array of registers and (b) the
+** collation sequences that should be used for the comparisons if
+** eTnctType is WHERE_DISTINCT_ORDERED.
+*/
+static int codeDistinct(
+  Parse *pParse,     /* Parsing and code generating context */
+  int eTnctType,     /* WHERE_DISTINCT_* value */
+  int iTab,          /* A sorting index used to test for distinctness */
+  int addrRepeat,    /* Jump to here if not distinct */
+  ExprList *pEList,  /* Expression for each element */
+  int regElem        /* First element */
+){
+  int iRet = 0;
+  int nResultCol = pEList->nExpr;
+  Vdbe *v = pParse->pVdbe;
+
+  switch( eTnctType ){
+    case WHERE_DISTINCT_ORDERED: {
+      int i;
+      int iJump;              /* Jump destination */
+      int regPrev;            /* Previous row content */
+
+      /* Allocate space for the previous row */
+      iRet = regPrev = pParse->nMem+1;
+      pParse->nMem += nResultCol;
+
+      iJump = sqlite3VdbeCurrentAddr(v) + nResultCol;
+      for(i=0; i<nResultCol; i++){
+        CollSeq *pColl = sqlite3ExprCollSeq(pParse, pEList->a[i].pExpr);
+        if( i<nResultCol-1 ){
+          sqlite3VdbeAddOp3(v, OP_Ne, regElem+i, iJump, regPrev+i);
+          VdbeCoverage(v);
+        }else{
+          sqlite3VdbeAddOp3(v, OP_Eq, regElem+i, addrRepeat, regPrev+i);
+          VdbeCoverage(v);
+         }
+        sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
+        sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
+      }
+      assert( sqlite3VdbeCurrentAddr(v)==iJump || pParse->db->mallocFailed );
+      sqlite3VdbeAddOp3(v, OP_Copy, regElem, regPrev, nResultCol-1);
+      break;
+    }
+
+    case WHERE_DISTINCT_UNIQUE: {
+      /* nothing to do */
+      break;
+    }
+
+    default: {
+      int r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp4Int(v, OP_Found, iTab, addrRepeat, regElem, nResultCol);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regElem, nResultCol, r1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iTab, r1, regElem, nResultCol);
+      sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+      sqlite3ReleaseTempReg(pParse, r1);
+      iRet = iTab;
+      break;
+    }
+  }
+
+  return iRet;
+}
+
+/*
+** This routine runs after codeDistinct().  It makes necessary
+** adjustments to the OP_OpenEphemeral opcode that the codeDistinct()
+** routine made use of.  This processing must be done separately since
+** sometimes codeDistinct is called before the OP_OpenEphemeral is actually
+** laid down.
+**
+** WHERE_DISTINCT_NOOP:
+** WHERE_DISTINCT_UNORDERED:
+**
+**     No adjustments necessary.  This function is a no-op.
+**
+** WHERE_DISTINCT_UNIQUE:
+**
+**     The ephemeral table is not needed.  So change the
+**     OP_OpenEphemeral opcode into an OP_Noop.
+**
+** WHERE_DISTINCT_ORDERED:
+**
+**     The ephemeral table is not needed.  But we do need register
+**     iVal to be initialized to NULL.  So change the OP_OpenEphemeral
+**     into an OP_Null on the iVal register.
+*/
+static void fixDistinctOpenEph(
+  Parse *pParse,     /* Parsing and code generating context */
+  int eTnctType,     /* WHERE_DISTINCT_* value */
+  int iVal,          /* Value returned by codeDistinct() */
+  int iOpenEphAddr   /* Address of OP_OpenEphemeral instruction for iTab */
+){
+  if( pParse->nErr==0
+   && (eTnctType==WHERE_DISTINCT_UNIQUE || eTnctType==WHERE_DISTINCT_ORDERED)
+  ){
+    Vdbe *v = pParse->pVdbe;
+    sqlite3VdbeChangeToNoop(v, iOpenEphAddr);
+    if( sqlite3VdbeGetOp(v, iOpenEphAddr+1)->opcode==OP_Explain ){
+      sqlite3VdbeChangeToNoop(v, iOpenEphAddr+1);
+    }
+    if( eTnctType==WHERE_DISTINCT_ORDERED ){
+      /* Change the OP_OpenEphemeral to an OP_Null that sets the MEM_Cleared
+      ** bit on the first register of the previous value.  This will cause the
+      ** OP_Ne added in codeDistinct() to always fail on the first iteration of
+      ** the loop even if the first row is all NULLs.  */
+      VdbeOp *pOp = sqlite3VdbeGetOp(v, iOpenEphAddr);
+      pOp->opcode = OP_Null;
+      pOp->p1 = 1;
+      pOp->p2 = iVal;
+    }
+  }
+}
+
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+/*
+** This function is called as part of inner-loop generation for a SELECT
+** statement with an ORDER BY that is not optimized by an index. It
+** determines the expressions, if any, that the sorter-reference
+** optimization should be used for. The sorter-reference optimization
+** is used for SELECT queries like:
+**
+**   SELECT a, bigblob FROM t1 ORDER BY a LIMIT 10
+**
+** If the optimization is used for expression "bigblob", then instead of
+** storing values read from that column in the sorter records, the PK of
+** the row from table t1 is stored instead. Then, as records are extracted from
+** the sorter to return to the user, the required value of bigblob is
+** retrieved directly from table t1. If the values are very large, this
+** can be more efficient than storing them directly in the sorter records.
+**
+** The ExprList_item.fg.bSorterRef flag is set for each expression in pEList
+** for which the sorter-reference optimization should be enabled.
+** Additionally, the pSort->aDefer[] array is populated with entries
+** for all cursors required to evaluate all selected expressions. Finally.
+** output variable (*ppExtra) is set to an expression list containing
+** expressions for all extra PK values that should be stored in the
+** sorter records.
+*/
+static void selectExprDefer(
+  Parse *pParse,                  /* Leave any error here */
+  SortCtx *pSort,                 /* Sorter context */
+  ExprList *pEList,               /* Expressions destined for sorter */
+  ExprList **ppExtra              /* Expressions to append to sorter record */
+){
+  int i;
+  int nDefer = 0;
+  ExprList *pExtra = 0;
+  for(i=0; i<pEList->nExpr; i++){
+    struct ExprList_item *pItem = &pEList->a[i];
+    if( pItem->u.x.iOrderByCol==0 ){
+      Expr *pExpr = pItem->pExpr;
+      Table *pTab;
+      if( pExpr->op==TK_COLUMN
+       && pExpr->iColumn>=0
+       && ALWAYS( ExprUseYTab(pExpr) )
+       && (pTab = pExpr->y.pTab)!=0
+       && IsOrdinaryTable(pTab)
+       && (pTab->aCol[pExpr->iColumn].colFlags & COLFLAG_SORTERREF)!=0
+      ){
+        int j;
+        for(j=0; j<nDefer; j++){
+          if( pSort->aDefer[j].iCsr==pExpr->iTable ) break;
+        }
+        if( j==nDefer ){
+          if( nDefer==ArraySize(pSort->aDefer) ){
+            continue;
+          }else{
+            int nKey = 1;
+            int k;
+            Index *pPk = 0;
+            if( !HasRowid(pTab) ){
+              pPk = sqlite3PrimaryKeyIndex(pTab);
+              nKey = pPk->nKeyCol;
+            }
+            for(k=0; k<nKey; k++){
+              Expr *pNew = sqlite3PExpr(pParse, TK_COLUMN, 0, 0);
+              if( pNew ){
+                pNew->iTable = pExpr->iTable;
+                assert( ExprUseYTab(pNew) );
+                pNew->y.pTab = pExpr->y.pTab;
+                pNew->iColumn = pPk ? pPk->aiColumn[k] : -1;
+                pExtra = sqlite3ExprListAppend(pParse, pExtra, pNew);
+              }
+            }
+            pSort->aDefer[nDefer].pTab = pExpr->y.pTab;
+            pSort->aDefer[nDefer].iCsr = pExpr->iTable;
+            pSort->aDefer[nDefer].nKey = nKey;
+            nDefer++;
+          }
+        }
+        pItem->fg.bSorterRef = 1;
+      }
+    }
+  }
+  pSort->nDefer = (u8)nDefer;
+  *ppExtra = pExtra;
+}
+#endif
+
+/*
+** This routine generates the code for the inside of the inner loop
+** of a SELECT.
+**
+** If srcTab is negative, then the p->pEList expressions
+** are evaluated in order to get the data for this row.  If srcTab is
+** zero or more, then data is pulled from srcTab and p->pEList is used only
+** to get the number of columns and the collation sequence for each column.
+*/
+static void selectInnerLoop(
+  Parse *pParse,          /* The parser context */
+  Select *p,              /* The complete select statement being coded */
+  int srcTab,             /* Pull data from this table if non-negative */
+  SortCtx *pSort,         /* If not NULL, info on how to process ORDER BY */
+  DistinctCtx *pDistinct, /* If not NULL, info on how to process DISTINCT */
+  SelectDest *pDest,      /* How to dispose of the results */
+  int iContinue,          /* Jump here to continue with next row */
+  int iBreak              /* Jump here to break out of the inner loop */
+){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  int hasDistinct;            /* True if the DISTINCT keyword is present */
+  int eDest = pDest->eDest;   /* How to dispose of results */
+  int iParm = pDest->iSDParm; /* First argument to disposal method */
+  int nResultCol;             /* Number of result columns */
+  int nPrefixReg = 0;         /* Number of extra registers before regResult */
+  RowLoadInfo sRowLoadInfo;   /* Info for deferred row loading */
+
+  /* Usually, regResult is the first cell in an array of memory cells
+  ** containing the current result row. In this case regOrig is set to the
+  ** same value. However, if the results are being sent to the sorter, the
+  ** values for any expressions that are also part of the sort-key are omitted
+  ** from this array. In this case regOrig is set to zero.  */
+  int regResult;              /* Start of memory holding current results */
+  int regOrig;                /* Start of memory holding full result (or 0) */
+
+  assert( v );
+  assert( p->pEList!=0 );
+  hasDistinct = pDistinct ? pDistinct->eTnctType : WHERE_DISTINCT_NOOP;
+  if( pSort && pSort->pOrderBy==0 ) pSort = 0;
+  if( pSort==0 && !hasDistinct ){
+    assert( iContinue!=0 );
+    codeOffset(v, p->iOffset, iContinue);
+  }
+
+  /* Pull the requested columns.
+  */
+  nResultCol = p->pEList->nExpr;
+
+  if( pDest->iSdst==0 ){
+    if( pSort ){
+      nPrefixReg = pSort->pOrderBy->nExpr;
+      if( !(pSort->sortFlags & SORTFLAG_UseSorter) ) nPrefixReg++;
+      pParse->nMem += nPrefixReg;
+    }
+    pDest->iSdst = pParse->nMem+1;
+    pParse->nMem += nResultCol;
+  }else if( pDest->iSdst+nResultCol > pParse->nMem ){
+    /* This is an error condition that can result, for example, when a SELECT
+    ** on the right-hand side of an INSERT contains more result columns than
+    ** there are columns in the table on the left.  The error will be caught
+    ** and reported later.  But we need to make sure enough memory is allocated
+    ** to avoid other spurious errors in the meantime. */
+    pParse->nMem += nResultCol;
+  }
+  pDest->nSdst = nResultCol;
+  regOrig = regResult = pDest->iSdst;
+  if( srcTab>=0 ){
+    for(i=0; i<nResultCol; i++){
+      sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
+      VdbeComment((v, "%s", p->pEList->a[i].zEName));
+    }
+  }else if( eDest!=SRT_Exists ){
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    ExprList *pExtra = 0;
+#endif
+    /* If the destination is an EXISTS(...) expression, the actual
+    ** values returned by the SELECT are not required.
+    */
+    u8 ecelFlags;    /* "ecel" is an abbreviation of "ExprCodeExprList" */
+    ExprList *pEList;
+    if( eDest==SRT_Mem || eDest==SRT_Output || eDest==SRT_Coroutine ){
+      ecelFlags = SQLITE_ECEL_DUP;
+    }else{
+      ecelFlags = 0;
+    }
+    if( pSort && hasDistinct==0 && eDest!=SRT_EphemTab && eDest!=SRT_Table ){
+      /* For each expression in p->pEList that is a copy of an expression in
+      ** the ORDER BY clause (pSort->pOrderBy), set the associated
+      ** iOrderByCol value to one more than the index of the ORDER BY
+      ** expression within the sort-key that pushOntoSorter() will generate.
+      ** This allows the p->pEList field to be omitted from the sorted record,
+      ** saving space and CPU cycles.  */
+      ecelFlags |= (SQLITE_ECEL_OMITREF|SQLITE_ECEL_REF);
+
+      for(i=pSort->nOBSat; i<pSort->pOrderBy->nExpr; i++){
+        int j;
+        if( (j = pSort->pOrderBy->a[i].u.x.iOrderByCol)>0 ){
+          p->pEList->a[j-1].u.x.iOrderByCol = i+1-pSort->nOBSat;
+        }
+      }
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+      selectExprDefer(pParse, pSort, p->pEList, &pExtra);
+      if( pExtra && pParse->db->mallocFailed==0 ){
+        /* If there are any extra PK columns to add to the sorter records,
+        ** allocate extra memory cells and adjust the OpenEphemeral
+        ** instruction to account for the larger records. This is only
+        ** required if there are one or more WITHOUT ROWID tables with
+        ** composite primary keys in the SortCtx.aDefer[] array.  */
+        VdbeOp *pOp = sqlite3VdbeGetOp(v, pSort->addrSortIndex);
+        pOp->p2 += (pExtra->nExpr - pSort->nDefer);
+        pOp->p4.pKeyInfo->nAllField += (pExtra->nExpr - pSort->nDefer);
+        pParse->nMem += pExtra->nExpr;
+      }
+#endif
+
+      /* Adjust nResultCol to account for columns that are omitted
+      ** from the sorter by the optimizations in this branch */
+      pEList = p->pEList;
+      for(i=0; i<pEList->nExpr; i++){
+        if( pEList->a[i].u.x.iOrderByCol>0
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+         || pEList->a[i].fg.bSorterRef
+#endif
+        ){
+          nResultCol--;
+          regOrig = 0;
+        }
+      }
+
+      testcase( regOrig );
+      testcase( eDest==SRT_Set );
+      testcase( eDest==SRT_Mem );
+      testcase( eDest==SRT_Coroutine );
+      testcase( eDest==SRT_Output );
+      assert( eDest==SRT_Set || eDest==SRT_Mem
+           || eDest==SRT_Coroutine || eDest==SRT_Output
+           || eDest==SRT_Upfrom );
+    }
+    sRowLoadInfo.regResult = regResult;
+    sRowLoadInfo.ecelFlags = ecelFlags;
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    sRowLoadInfo.pExtra = pExtra;
+    sRowLoadInfo.regExtraResult = regResult + nResultCol;
+    if( pExtra ) nResultCol += pExtra->nExpr;
+#endif
+    if( p->iLimit
+     && (ecelFlags & SQLITE_ECEL_OMITREF)!=0
+     && nPrefixReg>0
+    ){
+      assert( pSort!=0 );
+      assert( hasDistinct==0 );
+      pSort->pDeferredRowLoad = &sRowLoadInfo;
+      regOrig = 0;
+    }else{
+      innerLoopLoadRow(pParse, p, &sRowLoadInfo);
+    }
+  }
+
+  /* If the DISTINCT keyword was present on the SELECT statement
+  ** and this row has been seen before, then do not make this row
+  ** part of the result.
+  */
+  if( hasDistinct ){
+    int eType = pDistinct->eTnctType;
+    int iTab = pDistinct->tabTnct;
+    assert( nResultCol==p->pEList->nExpr );
+    iTab = codeDistinct(pParse, eType, iTab, iContinue, p->pEList, regResult);
+    fixDistinctOpenEph(pParse, eType, iTab, pDistinct->addrTnct);
+    if( pSort==0 ){
+      codeOffset(v, p->iOffset, iContinue);
+    }
+  }
+
+  switch( eDest ){
+    /* In this mode, write each query result to the key of the temporary
+    ** table iParm.
+    */
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+    case SRT_Union: {
+      int r1;
+      r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, nResultCol);
+      sqlite3ReleaseTempReg(pParse, r1);
+      break;
+    }
+
+    /* Construct a record from the query result, but instead of
+    ** saving that record, use it as a key to delete elements from
+    ** the temporary table iParm.
+    */
+    case SRT_Except: {
+      sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nResultCol);
+      break;
+    }
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+    /* Store the result as data using a unique key.
+    */
+    case SRT_Fifo:
+    case SRT_DistFifo:
+    case SRT_Table:
+    case SRT_EphemTab: {
+      int r1 = sqlite3GetTempRange(pParse, nPrefixReg+1);
+      testcase( eDest==SRT_Table );
+      testcase( eDest==SRT_EphemTab );
+      testcase( eDest==SRT_Fifo );
+      testcase( eDest==SRT_DistFifo );
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1+nPrefixReg);
+#if !defined(SQLITE_ENABLE_NULL_TRIM) && defined(SQLITE_DEBUG)
+      /* A destination of SRT_Table and a non-zero iSDParm2 parameter means
+      ** that this is an "UPDATE ... FROM" on a virtual table or view. In this
+      ** case set the p5 parameter of the OP_MakeRecord to OPFLAG_NOCHNG_MAGIC.
+      ** This does not affect operation in any way - it just allows MakeRecord
+      ** to process OPFLAG_NOCHANGE values without an assert() failing. */
+      if( eDest==SRT_Table && pDest->iSDParm2 ){
+        sqlite3VdbeChangeP5(v, OPFLAG_NOCHNG_MAGIC);
+      }
+#endif
+#ifndef SQLITE_OMIT_CTE
+      if( eDest==SRT_DistFifo ){
+        /* If the destination is DistFifo, then cursor (iParm+1) is open
+        ** on an ephemeral index. If the current row is already present
+        ** in the index, do not write it to the output. If not, add the
+        ** current row to the index and proceed with writing it to the
+        ** output table as well.  */
+        int addr = sqlite3VdbeCurrentAddr(v) + 4;
+        sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, addr, r1, 0);
+        VdbeCoverage(v);
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm+1, r1,regResult,nResultCol);
+        assert( pSort==0 );
+      }
+#endif
+      if( pSort ){
+        assert( regResult==regOrig );
+        pushOntoSorter(pParse, pSort, p, r1+nPrefixReg, regOrig, 1, nPrefixReg);
+      }else{
+        int r2 = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
+        sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
+        sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+        sqlite3ReleaseTempReg(pParse, r2);
+      }
+      sqlite3ReleaseTempRange(pParse, r1, nPrefixReg+1);
+      break;
+    }
+
+    case SRT_Upfrom: {
+      if( pSort ){
+        pushOntoSorter(
+            pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg);
+      }else{
+        int i2 = pDest->iSDParm2;
+        int r1 = sqlite3GetTempReg(pParse);
+
+        /* If the UPDATE FROM join is an aggregate that matches no rows, it
+        ** might still be trying to return one row, because that is what
+        ** aggregates do.  Don't record that empty row in the output table. */
+        sqlite3VdbeAddOp2(v, OP_IsNull, regResult, iBreak); VdbeCoverage(v);
+
+        sqlite3VdbeAddOp3(v, OP_MakeRecord,
+                          regResult+(i2<0), nResultCol-(i2<0), r1);
+        if( i2<0 ){
+          sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, regResult);
+        }else{
+          sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, i2);
+        }
+      }
+      break;
+    }
+
+#ifndef SQLITE_OMIT_SUBQUERY
+    /* If we are creating a set for an "expr IN (SELECT ...)" construct,
+    ** then there should be a single item on the stack.  Write this
+    ** item into the set table with bogus data.
+    */
+    case SRT_Set: {
+      if( pSort ){
+        /* At first glance you would think we could optimize out the
+        ** ORDER BY in this case since the order of entries in the set
+        ** does not matter.  But there might be a LIMIT clause, in which
+        ** case the order does matter */
+        pushOntoSorter(
+            pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg);
+        pDest->iSDParm2 = 0; /* Signal that any Bloom filter is unpopulated */
+      }else{
+        int r1 = sqlite3GetTempReg(pParse);
+        assert( sqlite3Strlen30(pDest->zAffSdst)==nResultCol );
+        sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, nResultCol,
+            r1, pDest->zAffSdst, nResultCol);
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, nResultCol);
+        if( pDest->iSDParm2 ){
+          sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pDest->iSDParm2, 0,
+                               regResult, nResultCol);
+          ExplainQueryPlan((pParse, 0, "CREATE BLOOM FILTER"));
+        }
+        sqlite3ReleaseTempReg(pParse, r1);
+      }
+      break;
+    }
+
+
+    /* If any row exist in the result set, record that fact and abort.
+    */
+    case SRT_Exists: {
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
+      /* The LIMIT clause will terminate the loop for us */
+      break;
+    }
+
+    /* If this is a scalar select that is part of an expression, then
+    ** store the results in the appropriate memory cell or array of
+    ** memory cells and break out of the scan loop.
+    */
+    case SRT_Mem: {
+      if( pSort ){
+        assert( nResultCol<=pDest->nSdst );
+        pushOntoSorter(
+            pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg);
+      }else{
+        assert( nResultCol==pDest->nSdst );
+        assert( regResult==iParm );
+        /* The LIMIT clause will jump out of the loop for us */
+      }
+      break;
+    }
+#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
+
+    case SRT_Coroutine:       /* Send data to a co-routine */
+    case SRT_Output: {        /* Return the results */
+      testcase( eDest==SRT_Coroutine );
+      testcase( eDest==SRT_Output );
+      if( pSort ){
+        pushOntoSorter(pParse, pSort, p, regResult, regOrig, nResultCol,
+                       nPrefixReg);
+      }else if( eDest==SRT_Coroutine ){
+        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nResultCol);
+      }
+      break;
+    }
+
+#ifndef SQLITE_OMIT_CTE
+    /* Write the results into a priority queue that is order according to
+    ** pDest->pOrderBy (in pSO).  pDest->iSDParm (in iParm) is the cursor for an
+    ** index with pSO->nExpr+2 columns.  Build a key using pSO for the first
+    ** pSO->nExpr columns, then make sure all keys are unique by adding a
+    ** final OP_Sequence column.  The last column is the record as a blob.
+    */
+    case SRT_DistQueue:
+    case SRT_Queue: {
+      int nKey;
+      int r1, r2, r3;
+      int addrTest = 0;
+      ExprList *pSO;
+      pSO = pDest->pOrderBy;
+      assert( pSO );
+      nKey = pSO->nExpr;
+      r1 = sqlite3GetTempReg(pParse);
+      r2 = sqlite3GetTempRange(pParse, nKey+2);
+      r3 = r2+nKey+1;
+      if( eDest==SRT_DistQueue ){
+        /* If the destination is DistQueue, then cursor (iParm+1) is open
+        ** on a second ephemeral index that holds all values every previously
+        ** added to the queue. */
+        addrTest = sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, 0,
+                                        regResult, nResultCol);
+        VdbeCoverage(v);
+      }
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r3);
+      if( eDest==SRT_DistQueue ){
+        sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm+1, r3);
+        sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+      }
+      for(i=0; i<nKey; i++){
+        sqlite3VdbeAddOp2(v, OP_SCopy,
+                          regResult + pSO->a[i].u.x.iOrderByCol - 1,
+                          r2+i);
+      }
+      sqlite3VdbeAddOp2(v, OP_Sequence, iParm, r2+nKey);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, r2, nKey+2, r1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, r2, nKey+2);
+      if( addrTest ) sqlite3VdbeJumpHere(v, addrTest);
+      sqlite3ReleaseTempReg(pParse, r1);
+      sqlite3ReleaseTempRange(pParse, r2, nKey+2);
+      break;
+    }
+#endif /* SQLITE_OMIT_CTE */
+
+
+
+#if !defined(SQLITE_OMIT_TRIGGER)
+    /* Discard the results.  This is used for SELECT statements inside
+    ** the body of a TRIGGER.  The purpose of such selects is to call
+    ** user-defined functions that have side effects.  We do not care
+    ** about the actual results of the select.
+    */
+    default: {
+      assert( eDest==SRT_Discard );
+      break;
+    }
+#endif
+  }
+
+  /* Jump to the end of the loop if the LIMIT is reached.  Except, if
+  ** there is a sorter, in which case the sorter has already limited
+  ** the output for us.
+  */
+  if( pSort==0 && p->iLimit ){
+    sqlite3VdbeAddOp2(v, OP_DecrJumpZero, p->iLimit, iBreak); VdbeCoverage(v);
+  }
+}
+
+/*
+** Allocate a KeyInfo object sufficient for an index of N key columns and
+** X extra columns.
+*/
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoAlloc(sqlite3 *db, int N, int X){
+  int nExtra = (N+X)*(sizeof(CollSeq*)+1) - sizeof(CollSeq*);
+  KeyInfo *p = sqlite3DbMallocRawNN(db, sizeof(KeyInfo) + nExtra);
+  if( p ){
+    p->aSortFlags = (u8*)&p->aColl[N+X];
+    p->nKeyField = (u16)N;
+    p->nAllField = (u16)(N+X);
+    p->enc = ENC(db);
+    p->db = db;
+    p->nRef = 1;
+    memset(&p[1], 0, nExtra);
+  }else{
+    return (KeyInfo*)sqlite3OomFault(db);
+  }
+  return p;
+}
+
+/*
+** Deallocate a KeyInfo object
+*/
+SQLITE_PRIVATE void sqlite3KeyInfoUnref(KeyInfo *p){
+  if( p ){
+    assert( p->db!=0 );
+    assert( p->nRef>0 );
+    p->nRef--;
+    if( p->nRef==0 ) sqlite3DbNNFreeNN(p->db, p);
+  }
+}
+
+/*
+** Make a new pointer to a KeyInfo object
+*/
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoRef(KeyInfo *p){
+  if( p ){
+    assert( p->nRef>0 );
+    p->nRef++;
+  }
+  return p;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Return TRUE if a KeyInfo object can be change.  The KeyInfo object
+** can only be changed if this is just a single reference to the object.
+**
+** This routine is used only inside of assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3KeyInfoIsWriteable(KeyInfo *p){ return p->nRef==1; }
+#endif /* SQLITE_DEBUG */
+
+/*
+** Given an expression list, generate a KeyInfo structure that records
+** the collating sequence for each expression in that expression list.
+**
+** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
+** KeyInfo structure is appropriate for initializing a virtual index to
+** implement that clause.  If the ExprList is the result set of a SELECT
+** then the KeyInfo structure is appropriate for initializing a virtual
+** index to implement a DISTINCT test.
+**
+** Space to hold the KeyInfo structure is obtained from malloc.  The calling
+** function is responsible for seeing that this structure is eventually
+** freed.
+*/
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoFromExprList(
+  Parse *pParse,       /* Parsing context */
+  ExprList *pList,     /* Form the KeyInfo object from this ExprList */
+  int iStart,          /* Begin with this column of pList */
+  int nExtra           /* Add this many extra columns to the end */
+){
+  int nExpr;
+  KeyInfo *pInfo;
+  struct ExprList_item *pItem;
+  sqlite3 *db = pParse->db;
+  int i;
+
+  nExpr = pList->nExpr;
+  pInfo = sqlite3KeyInfoAlloc(db, nExpr-iStart, nExtra+1);
+  if( pInfo ){
+    assert( sqlite3KeyInfoIsWriteable(pInfo) );
+    for(i=iStart, pItem=pList->a+iStart; i<nExpr; i++, pItem++){
+      pInfo->aColl[i-iStart] = sqlite3ExprNNCollSeq(pParse, pItem->pExpr);
+      pInfo->aSortFlags[i-iStart] = pItem->fg.sortFlags;
+    }
+  }
+  return pInfo;
+}
+
+/*
+** Name of the connection operator, used for error messages.
+*/
+SQLITE_PRIVATE const char *sqlite3SelectOpName(int id){
+  char *z;
+  switch( id ){
+    case TK_ALL:       z = "UNION ALL";   break;
+    case TK_INTERSECT: z = "INTERSECT";   break;
+    case TK_EXCEPT:    z = "EXCEPT";      break;
+    default:           z = "UNION";       break;
+  }
+  return z;
+}
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
+** is a no-op. Otherwise, it adds a single row of output to the EQP result,
+** where the caption is of the form:
+**
+**   "USE TEMP B-TREE FOR xxx"
+**
+** where xxx is one of "DISTINCT", "ORDER BY" or "GROUP BY". Exactly which
+** is determined by the zUsage argument.
+*/
+static void explainTempTable(Parse *pParse, const char *zUsage){
+  ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s", zUsage));
+}
+
+/*
+** Assign expression b to lvalue a. A second, no-op, version of this macro
+** is provided when SQLITE_OMIT_EXPLAIN is defined. This allows the code
+** in sqlite3Select() to assign values to structure member variables that
+** only exist if SQLITE_OMIT_EXPLAIN is not defined without polluting the
+** code with #ifndef directives.
+*/
+# define explainSetInteger(a, b) a = b
+
+#else
+/* No-op versions of the explainXXX() functions and macros. */
+# define explainTempTable(y,z)
+# define explainSetInteger(y,z)
+#endif
+
+
+/*
+** If the inner loop was generated using a non-null pOrderBy argument,
+** then the results were placed in a sorter.  After the loop is terminated
+** we need to run the sorter and output the results.  The following
+** routine generates the code needed to do that.
+*/
+static void generateSortTail(
+  Parse *pParse,    /* Parsing context */
+  Select *p,        /* The SELECT statement */
+  SortCtx *pSort,   /* Information on the ORDER BY clause */
+  int nColumn,      /* Number of columns of data */
+  SelectDest *pDest /* Write the sorted results here */
+){
+  Vdbe *v = pParse->pVdbe;                     /* The prepared statement */
+  int addrBreak = pSort->labelDone;            /* Jump here to exit loop */
+  int addrContinue = sqlite3VdbeMakeLabel(pParse);/* Jump here for next cycle */
+  int addr;                       /* Top of output loop. Jump for Next. */
+  int addrOnce = 0;
+  int iTab;
+  ExprList *pOrderBy = pSort->pOrderBy;
+  int eDest = pDest->eDest;
+  int iParm = pDest->iSDParm;
+  int regRow;
+  int regRowid;
+  int iCol;
+  int nKey;                       /* Number of key columns in sorter record */
+  int iSortTab;                   /* Sorter cursor to read from */
+  int i;
+  int bSeq;                       /* True if sorter record includes seq. no. */
+  int nRefKey = 0;
+  struct ExprList_item *aOutEx = p->pEList->a;
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrExplain;                /* Address of OP_Explain instruction */
+#endif
+
+  nKey = pOrderBy->nExpr - pSort->nOBSat;
+  if( pSort->nOBSat==0 || nKey==1 ){
+    ExplainQueryPlan2(addrExplain, (pParse, 0,
+      "USE TEMP B-TREE FOR %sORDER BY", pSort->nOBSat?"LAST TERM OF ":""
+    ));
+  }else{
+    ExplainQueryPlan2(addrExplain, (pParse, 0,
+      "USE TEMP B-TREE FOR LAST %d TERMS OF ORDER BY", nKey
+    ));
+  }
+  sqlite3VdbeScanStatusRange(v, addrExplain,pSort->addrPush,pSort->addrPushEnd);
+  sqlite3VdbeScanStatusCounters(v, addrExplain, addrExplain, pSort->addrPush);
+
+
+  assert( addrBreak<0 );
+  if( pSort->labelBkOut ){
+    sqlite3VdbeAddOp2(v, OP_Gosub, pSort->regReturn, pSort->labelBkOut);
+    sqlite3VdbeGoto(v, addrBreak);
+    sqlite3VdbeResolveLabel(v, pSort->labelBkOut);
+  }
+
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  /* Open any cursors needed for sorter-reference expressions */
+  for(i=0; i<pSort->nDefer; i++){
+    Table *pTab = pSort->aDefer[i].pTab;
+    int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+    sqlite3OpenTable(pParse, pSort->aDefer[i].iCsr, iDb, pTab, OP_OpenRead);
+    nRefKey = MAX(nRefKey, pSort->aDefer[i].nKey);
+  }
+#endif
+
+  iTab = pSort->iECursor;
+  if( eDest==SRT_Output || eDest==SRT_Coroutine || eDest==SRT_Mem ){
+    if( eDest==SRT_Mem && p->iOffset ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, pDest->iSdst);
+    }
+    regRowid = 0;
+    regRow = pDest->iSdst;
+  }else{
+    regRowid = sqlite3GetTempReg(pParse);
+    if( eDest==SRT_EphemTab || eDest==SRT_Table ){
+      regRow = sqlite3GetTempReg(pParse);
+      nColumn = 0;
+    }else{
+      regRow = sqlite3GetTempRange(pParse, nColumn);
+    }
+  }
+  if( pSort->sortFlags & SORTFLAG_UseSorter ){
+    int regSortOut = ++pParse->nMem;
+    iSortTab = pParse->nTab++;
+    if( pSort->labelBkOut ){
+      addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+    }
+    sqlite3VdbeAddOp3(v, OP_OpenPseudo, iSortTab, regSortOut,
+        nKey+1+nColumn+nRefKey);
+    if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
+    addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak);
+    VdbeCoverage(v);
+    assert( p->iLimit==0 && p->iOffset==0 );
+    sqlite3VdbeAddOp3(v, OP_SorterData, iTab, regSortOut, iSortTab);
+    bSeq = 0;
+  }else{
+    addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak); VdbeCoverage(v);
+    codeOffset(v, p->iOffset, addrContinue);
+    iSortTab = iTab;
+    bSeq = 1;
+    if( p->iOffset>0 ){
+      sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
+    }
+  }
+  for(i=0, iCol=nKey+bSeq-1; i<nColumn; i++){
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( aOutEx[i].fg.bSorterRef ) continue;
+#endif
+    if( aOutEx[i].u.x.iOrderByCol==0 ) iCol++;
+  }
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  if( pSort->nDefer ){
+    int iKey = iCol+1;
+    int regKey = sqlite3GetTempRange(pParse, nRefKey);
+
+    for(i=0; i<pSort->nDefer; i++){
+      int iCsr = pSort->aDefer[i].iCsr;
+      Table *pTab = pSort->aDefer[i].pTab;
+      int nKey = pSort->aDefer[i].nKey;
+
+      sqlite3VdbeAddOp1(v, OP_NullRow, iCsr);
+      if( HasRowid(pTab) ){
+        sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iKey++, regKey);
+        sqlite3VdbeAddOp3(v, OP_SeekRowid, iCsr,
+            sqlite3VdbeCurrentAddr(v)+1, regKey);
+      }else{
+        int k;
+        int iJmp;
+        assert( sqlite3PrimaryKeyIndex(pTab)->nKeyCol==nKey );
+        for(k=0; k<nKey; k++){
+          sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iKey++, regKey+k);
+        }
+        iJmp = sqlite3VdbeCurrentAddr(v);
+        sqlite3VdbeAddOp4Int(v, OP_SeekGE, iCsr, iJmp+2, regKey, nKey);
+        sqlite3VdbeAddOp4Int(v, OP_IdxLE, iCsr, iJmp+3, regKey, nKey);
+        sqlite3VdbeAddOp1(v, OP_NullRow, iCsr);
+      }
+    }
+    sqlite3ReleaseTempRange(pParse, regKey, nRefKey);
+  }
+#endif
+  for(i=nColumn-1; i>=0; i--){
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( aOutEx[i].fg.bSorterRef ){
+      sqlite3ExprCode(pParse, aOutEx[i].pExpr, regRow+i);
+    }else
+#endif
+    {
+      int iRead;
+      if( aOutEx[i].u.x.iOrderByCol ){
+        iRead = aOutEx[i].u.x.iOrderByCol-1;
+      }else{
+        iRead = iCol--;
+      }
+      sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iRead, regRow+i);
+      VdbeComment((v, "%s", aOutEx[i].zEName));
+    }
+  }
+  sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1);
+  switch( eDest ){
+    case SRT_Table:
+    case SRT_EphemTab: {
+      sqlite3VdbeAddOp3(v, OP_Column, iSortTab, nKey+bSeq, regRow);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, iParm, regRow, regRowid);
+      sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case SRT_Set: {
+      assert( nColumn==sqlite3Strlen30(pDest->zAffSdst) );
+      sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, nColumn, regRowid,
+                        pDest->zAffSdst, nColumn);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, regRowid, regRow, nColumn);
+      break;
+    }
+    case SRT_Mem: {
+      /* The LIMIT clause will terminate the loop for us */
+      break;
+    }
+#endif
+    case SRT_Upfrom: {
+      int i2 = pDest->iSDParm2;
+      int r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord,regRow+(i2<0),nColumn-(i2<0),r1);
+      if( i2<0 ){
+        sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, regRow);
+      }else{
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regRow, i2);
+      }
+      break;
+    }
+    default: {
+      assert( eDest==SRT_Output || eDest==SRT_Coroutine );
+      testcase( eDest==SRT_Output );
+      testcase( eDest==SRT_Coroutine );
+      if( eDest==SRT_Output ){
+        sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iSdst, nColumn);
+      }else{
+        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
+      }
+      break;
+    }
+  }
+  if( regRowid ){
+    if( eDest==SRT_Set ){
+      sqlite3ReleaseTempRange(pParse, regRow, nColumn);
+    }else{
+      sqlite3ReleaseTempReg(pParse, regRow);
+    }
+    sqlite3ReleaseTempReg(pParse, regRowid);
+  }
+  /* The bottom of the loop
+  */
+  sqlite3VdbeResolveLabel(v, addrContinue);
+  if( pSort->sortFlags & SORTFLAG_UseSorter ){
+    sqlite3VdbeAddOp2(v, OP_SorterNext, iTab, addr); VdbeCoverage(v);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Next, iTab, addr); VdbeCoverage(v);
+  }
+  sqlite3VdbeScanStatusRange(v, addrExplain, sqlite3VdbeCurrentAddr(v)-1, -1);
+  if( pSort->regReturn ) sqlite3VdbeAddOp1(v, OP_Return, pSort->regReturn);
+  sqlite3VdbeResolveLabel(v, addrBreak);
+}
+
+/*
+** Return a pointer to a string containing the 'declaration type' of the
+** expression pExpr. The string may be treated as static by the caller.
+**
+** The declaration type is the exact datatype definition extracted from the
+** original CREATE TABLE statement if the expression is a column. The
+** declaration type for a ROWID field is INTEGER. Exactly when an expression
+** is considered a column can be complex in the presence of subqueries. The
+** result-set expression in all of the following SELECT statements is
+** considered a column by this function.
+**
+**   SELECT col FROM tbl;
+**   SELECT (SELECT col FROM tbl;
+**   SELECT (SELECT col FROM tbl);
+**   SELECT abc FROM (SELECT col AS abc FROM tbl);
+**
+** The declaration type for any expression other than a column is NULL.
+**
+** This routine has either 3 or 6 parameters depending on whether or not
+** the SQLITE_ENABLE_COLUMN_METADATA compile-time option is used.
+*/
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+# define columnType(A,B,C,D,E) columnTypeImpl(A,B,C,D,E)
+#else /* if !defined(SQLITE_ENABLE_COLUMN_METADATA) */
+# define columnType(A,B,C,D,E) columnTypeImpl(A,B)
+#endif
+static const char *columnTypeImpl(
+  NameContext *pNC,
+#ifndef SQLITE_ENABLE_COLUMN_METADATA
+  Expr *pExpr
+#else
+  Expr *pExpr,
+  const char **pzOrigDb,
+  const char **pzOrigTab,
+  const char **pzOrigCol
+#endif
+){
+  char const *zType = 0;
+  int j;
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+  char const *zOrigDb = 0;
+  char const *zOrigTab = 0;
+  char const *zOrigCol = 0;
+#endif
+
+  assert( pExpr!=0 );
+  assert( pNC->pSrcList!=0 );
+  switch( pExpr->op ){
+    case TK_COLUMN: {
+      /* The expression is a column. Locate the table the column is being
+      ** extracted from in NameContext.pSrcList. This table may be real
+      ** database table or a subquery.
+      */
+      Table *pTab = 0;            /* Table structure column is extracted from */
+      Select *pS = 0;             /* Select the column is extracted from */
+      int iCol = pExpr->iColumn;  /* Index of column in pTab */
+      while( pNC && !pTab ){
+        SrcList *pTabList = pNC->pSrcList;
+        for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
+        if( j<pTabList->nSrc ){
+          pTab = pTabList->a[j].pSTab;
+          if( pTabList->a[j].fg.isSubquery ){
+            pS = pTabList->a[j].u4.pSubq->pSelect;
+          }else{
+            pS = 0;
+          }
+        }else{
+          pNC = pNC->pNext;
+        }
+      }
+
+      if( pTab==0 ){
+        /* At one time, code such as "SELECT new.x" within a trigger would
+        ** cause this condition to run.  Since then, we have restructured how
+        ** trigger code is generated and so this condition is no longer
+        ** possible. However, it can still be true for statements like
+        ** the following:
+        **
+        **   CREATE TABLE t1(col INTEGER);
+        **   SELECT (SELECT t1.col) FROM FROM t1;
+        **
+        ** when columnType() is called on the expression "t1.col" in the
+        ** sub-select. In this case, set the column type to NULL, even
+        ** though it should really be "INTEGER".
+        **
+        ** This is not a problem, as the column type of "t1.col" is never
+        ** used. When columnType() is called on the expression
+        ** "(SELECT t1.col)", the correct type is returned (see the TK_SELECT
+        ** branch below.  */
+        break;
+      }
+
+      assert( pTab && ExprUseYTab(pExpr) && pExpr->y.pTab==pTab );
+      if( pS ){
+        /* The "table" is actually a sub-select or a view in the FROM clause
+        ** of the SELECT statement. Return the declaration type and origin
+        ** data for the result-set column of the sub-select.
+        */
+        if( iCol<pS->pEList->nExpr
+         && (!ViewCanHaveRowid || iCol>=0)
+        ){
+          /* If iCol is less than zero, then the expression requests the
+          ** rowid of the sub-select or view. This expression is legal (see
+          ** test case misc2.2.2) - it always evaluates to NULL.
+          */
+          NameContext sNC;
+          Expr *p = pS->pEList->a[iCol].pExpr;
+          sNC.pSrcList = pS->pSrc;
+          sNC.pNext = pNC;
+          sNC.pParse = pNC->pParse;
+          zType = columnType(&sNC, p,&zOrigDb,&zOrigTab,&zOrigCol);
+        }
+      }else{
+        /* A real table or a CTE table */
+        assert( !pS );
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+        if( iCol<0 ) iCol = pTab->iPKey;
+        assert( iCol==XN_ROWID || (iCol>=0 && iCol<pTab->nCol) );
+        if( iCol<0 ){
+          zType = "INTEGER";
+          zOrigCol = "rowid";
+        }else{
+          zOrigCol = pTab->aCol[iCol].zCnName;
+          zType = sqlite3ColumnType(&pTab->aCol[iCol],0);
+        }
+        zOrigTab = pTab->zName;
+        if( pNC->pParse && pTab->pSchema ){
+          int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
+          zOrigDb = pNC->pParse->db->aDb[iDb].zDbSName;
+        }
+#else
+        assert( iCol==XN_ROWID || (iCol>=0 && iCol<pTab->nCol) );
+        if( iCol<0 ){
+          zType = "INTEGER";
+        }else{
+          zType = sqlite3ColumnType(&pTab->aCol[iCol],0);
+        }
+#endif
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_SELECT: {
+      /* The expression is a sub-select. Return the declaration type and
+      ** origin info for the single column in the result set of the SELECT
+      ** statement.
+      */
+      NameContext sNC;
+      Select *pS;
+      Expr *p;
+      assert( ExprUseXSelect(pExpr) );
+      pS = pExpr->x.pSelect;
+      p = pS->pEList->a[0].pExpr;
+      sNC.pSrcList = pS->pSrc;
+      sNC.pNext = pNC;
+      sNC.pParse = pNC->pParse;
+      zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
+      break;
+    }
+#endif
+  }
+
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+  if( pzOrigDb ){
+    assert( pzOrigTab && pzOrigCol );
+    *pzOrigDb = zOrigDb;
+    *pzOrigTab = zOrigTab;
+    *pzOrigCol = zOrigCol;
+  }
+#endif
+  return zType;
+}
+
+/*
+** Generate code that will tell the VDBE the declaration types of columns
+** in the result set.
+*/
+static void generateColumnTypes(
+  Parse *pParse,      /* Parser context */
+  SrcList *pTabList,  /* List of tables */
+  ExprList *pEList    /* Expressions defining the result set */
+){
+#ifndef SQLITE_OMIT_DECLTYPE
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  NameContext sNC;
+  sNC.pSrcList = pTabList;
+  sNC.pParse = pParse;
+  sNC.pNext = 0;
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *p = pEList->a[i].pExpr;
+    const char *zType;
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+    const char *zOrigDb = 0;
+    const char *zOrigTab = 0;
+    const char *zOrigCol = 0;
+    zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
+
+    /* The vdbe must make its own copy of the column-type and other
+    ** column specific strings, in case the schema is reset before this
+    ** virtual machine is deleted.
+    */
+    sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, SQLITE_TRANSIENT);
+    sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, SQLITE_TRANSIENT);
+    sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, SQLITE_TRANSIENT);
+#else
+    zType = columnType(&sNC, p, 0, 0, 0);
+#endif
+    sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, SQLITE_TRANSIENT);
+  }
+#endif /* !defined(SQLITE_OMIT_DECLTYPE) */
+}
+
+
+/*
+** Compute the column names for a SELECT statement.
+**
+** The only guarantee that SQLite makes about column names is that if the
+** column has an AS clause assigning it a name, that will be the name used.
+** That is the only documented guarantee.  However, countless applications
+** developed over the years have made baseless assumptions about column names
+** and will break if those assumptions changes.  Hence, use extreme caution
+** when modifying this routine to avoid breaking legacy.
+**
+** See Also: sqlite3ColumnsFromExprList()
+**
+** The PRAGMA short_column_names and PRAGMA full_column_names settings are
+** deprecated.  The default setting is short=ON, full=OFF.  99.9% of all
+** applications should operate this way.  Nevertheless, we need to support the
+** other modes for legacy:
+**
+**    short=OFF, full=OFF:      Column name is the text of the expression has it
+**                              originally appears in the SELECT statement.  In
+**                              other words, the zSpan of the result expression.
+**
+**    short=ON, full=OFF:       (This is the default setting).  If the result
+**                              refers directly to a table column, then the
+**                              result column name is just the table column
+**                              name: COLUMN.  Otherwise use zSpan.
+**
+**    full=ON, short=ANY:       If the result refers directly to a table column,
+**                              then the result column name with the table name
+**                              prefix, ex: TABLE.COLUMN.  Otherwise use zSpan.
+*/
+SQLITE_PRIVATE void sqlite3GenerateColumnNames(
+  Parse *pParse,      /* Parser context */
+  Select *pSelect     /* Generate column names for this SELECT statement */
+){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  Table *pTab;
+  SrcList *pTabList;
+  ExprList *pEList;
+  sqlite3 *db = pParse->db;
+  int fullName;    /* TABLE.COLUMN if no AS clause and is a direct table ref */
+  int srcName;     /* COLUMN or TABLE.COLUMN if no AS clause and is direct */
+
+  if( pParse->colNamesSet ) return;
+  /* Column names are determined by the left-most term of a compound select */
+  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
+  TREETRACE(0x80,pParse,pSelect,("generating column names\n"));
+  pTabList = pSelect->pSrc;
+  pEList = pSelect->pEList;
+  assert( v!=0 );
+  assert( pTabList!=0 );
+  pParse->colNamesSet = 1;
+  fullName = (db->flags & SQLITE_FullColNames)!=0;
+  srcName = (db->flags & SQLITE_ShortColNames)!=0 || fullName;
+  sqlite3VdbeSetNumCols(v, pEList->nExpr);
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *p = pEList->a[i].pExpr;
+
+    assert( p!=0 );
+    assert( p->op!=TK_AGG_COLUMN );  /* Agg processing has not run yet */
+    assert( p->op!=TK_COLUMN
+        || (ExprUseYTab(p) && p->y.pTab!=0) ); /* Covering idx not yet coded */
+    if( pEList->a[i].zEName && pEList->a[i].fg.eEName==ENAME_NAME ){
+      /* An AS clause always takes first priority */
+      char *zName = pEList->a[i].zEName;
+      sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT);
+    }else if( srcName && p->op==TK_COLUMN ){
+      char *zCol;
+      int iCol = p->iColumn;
+      pTab = p->y.pTab;
+      assert( pTab!=0 );
+      if( iCol<0 ) iCol = pTab->iPKey;
+      assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
+      if( iCol<0 ){
+        zCol = "rowid";
+      }else{
+        zCol = pTab->aCol[iCol].zCnName;
+      }
+      if( fullName ){
+        char *zName = 0;
+        zName = sqlite3MPrintf(db, "%s.%s", pTab->zName, zCol);
+        sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_DYNAMIC);
+      }else{
+        sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, SQLITE_TRANSIENT);
+      }
+    }else{
+      const char *z = pEList->a[i].zEName;
+      z = z==0 ? sqlite3MPrintf(db, "column%d", i+1) : sqlite3DbStrDup(db, z);
+      sqlite3VdbeSetColName(v, i, COLNAME_NAME, z, SQLITE_DYNAMIC);
+    }
+  }
+  generateColumnTypes(pParse, pTabList, pEList);
+}
+
+/*
+** Given an expression list (which is really the list of expressions
+** that form the result set of a SELECT statement) compute appropriate
+** column names for a table that would hold the expression list.
+**
+** All column names will be unique.
+**
+** Only the column names are computed.  Column.zType, Column.zColl,
+** and other fields of Column are zeroed.
+**
+** Return SQLITE_OK on success.  If a memory allocation error occurs,
+** store NULL in *paCol and 0 in *pnCol and return SQLITE_NOMEM.
+**
+** The only guarantee that SQLite makes about column names is that if the
+** column has an AS clause assigning it a name, that will be the name used.
+** That is the only documented guarantee.  However, countless applications
+** developed over the years have made baseless assumptions about column names
+** and will break if those assumptions changes.  Hence, use extreme caution
+** when modifying this routine to avoid breaking legacy.
+**
+** See Also: sqlite3GenerateColumnNames()
+*/
+SQLITE_PRIVATE int sqlite3ColumnsFromExprList(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pEList,       /* Expr list from which to derive column names */
+  i16 *pnCol,             /* Write the number of columns here */
+  Column **paCol          /* Write the new column list here */
+){
+  sqlite3 *db = pParse->db;   /* Database connection */
+  int i, j;                   /* Loop counters */
+  u32 cnt;                    /* Index added to make the name unique */
+  Column *aCol, *pCol;        /* For looping over result columns */
+  int nCol;                   /* Number of columns in the result set */
+  char *zName;                /* Column name */
+  int nName;                  /* Size of name in zName[] */
+  Hash ht;                    /* Hash table of column names */
+  Table *pTab;
+
+  sqlite3HashInit(&ht);
+  if( pEList ){
+    nCol = pEList->nExpr;
+    aCol = sqlite3DbMallocZero(db, sizeof(aCol[0])*nCol);
+    testcase( aCol==0 );
+    if( NEVER(nCol>32767) ) nCol = 32767;
+  }else{
+    nCol = 0;
+    aCol = 0;
+  }
+  assert( nCol==(i16)nCol );
+  *pnCol = nCol;
+  *paCol = aCol;
+
+  for(i=0, pCol=aCol; i<nCol && !pParse->nErr; i++, pCol++){
+    struct ExprList_item *pX = &pEList->a[i];
+    struct ExprList_item *pCollide;
+    /* Get an appropriate name for the column
+    */
+    if( (zName = pX->zEName)!=0 && pX->fg.eEName==ENAME_NAME ){
+      /* If the column contains an "AS <name>" phrase, use <name> as the name */
+    }else{
+      Expr *pColExpr = sqlite3ExprSkipCollateAndLikely(pX->pExpr);
+      while( ALWAYS(pColExpr!=0) && pColExpr->op==TK_DOT ){
+        pColExpr = pColExpr->pRight;
+        assert( pColExpr!=0 );
+      }
+      if( pColExpr->op==TK_COLUMN
+       && ALWAYS( ExprUseYTab(pColExpr) )
+       && ALWAYS( pColExpr->y.pTab!=0 )
+      ){
+        /* For columns use the column name name */
+        int iCol = pColExpr->iColumn;
+        pTab = pColExpr->y.pTab;
+        if( iCol<0 ) iCol = pTab->iPKey;
+        zName = iCol>=0 ? pTab->aCol[iCol].zCnName : "rowid";
+      }else if( pColExpr->op==TK_ID ){
+        assert( !ExprHasProperty(pColExpr, EP_IntValue) );
+        zName = pColExpr->u.zToken;
+      }else{
+        /* Use the original text of the column expression as its name */
+        assert( zName==pX->zEName );  /* pointer comparison intended */
+      }
+    }
+    if( zName && !sqlite3IsTrueOrFalse(zName) ){
+      zName = sqlite3DbStrDup(db, zName);
+    }else{
+      zName = sqlite3MPrintf(db,"column%d",i+1);
+    }
+
+    /* Make sure the column name is unique.  If the name is not unique,
+    ** append an integer to the name so that it becomes unique.
+    */
+    cnt = 0;
+    while( zName && (pCollide = sqlite3HashFind(&ht, zName))!=0 ){
+      if( pCollide->fg.bUsingTerm ){
+        pCol->colFlags |= COLFLAG_NOEXPAND;
+      }
+      nName = sqlite3Strlen30(zName);
+      if( nName>0 ){
+        for(j=nName-1; j>0 && sqlite3Isdigit(zName[j]); j--){}
+        if( zName[j]==':' ) nName = j;
+      }
+      zName = sqlite3MPrintf(db, "%.*z:%u", nName, zName, ++cnt);
+      sqlite3ProgressCheck(pParse);
+      if( cnt>3 ){
+        sqlite3_randomness(sizeof(cnt), &cnt);
+      }
+    }
+    pCol->zCnName = zName;
+    pCol->hName = sqlite3StrIHash(zName);
+    if( pX->fg.bNoExpand ){
+      pCol->colFlags |= COLFLAG_NOEXPAND;
+    }
+    sqlite3ColumnPropertiesFromName(0, pCol);
+    if( zName && sqlite3HashInsert(&ht, zName, pX)==pX ){
+      sqlite3OomFault(db);
+    }
+  }
+  sqlite3HashClear(&ht);
+  if( pParse->nErr ){
+    for(j=0; j<i; j++){
+      sqlite3DbFree(db, aCol[j].zCnName);
+    }
+    sqlite3DbFree(db, aCol);
+    *paCol = 0;
+    *pnCol = 0;
+    return pParse->rc;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** pTab is a transient Table object that represents a subquery of some
+** kind (maybe a parenthesized subquery in the FROM clause of a larger
+** query, or a VIEW, or a CTE).  This routine computes type information
+** for that Table object based on the Select object that implements the
+** subquery.  For the purposes of this routine, "type information" means:
+**
+**    *   The datatype name, as it might appear in a CREATE TABLE statement
+**    *   Which collating sequence to use for the column
+**    *   The affinity of the column
+*/
+SQLITE_PRIVATE void sqlite3SubqueryColumnTypes(
+  Parse *pParse,      /* Parsing contexts */
+  Table *pTab,        /* Add column type information to this table */
+  Select *pSelect,    /* SELECT used to determine types and collations */
+  char aff            /* Default affinity. */
+){
+  sqlite3 *db = pParse->db;
+  Column *pCol;
+  CollSeq *pColl;
+  int i,j;
+  Expr *p;
+  struct ExprList_item *a;
+  NameContext sNC;
+
+  assert( pSelect!=0 );
+  assert( (pSelect->selFlags & SF_Resolved)!=0 );
+  assert( pTab->nCol==pSelect->pEList->nExpr || pParse->nErr>0 );
+  assert( aff==SQLITE_AFF_NONE || aff==SQLITE_AFF_BLOB );
+  if( db->mallocFailed || IN_RENAME_OBJECT ) return;
+  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
+  a = pSelect->pEList->a;
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pSrcList = pSelect->pSrc;
+  for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
+    const char *zType;
+    i64 n;
+    int m = 0;
+    Select *pS2 = pSelect;
+    pTab->tabFlags |= (pCol->colFlags & COLFLAG_NOINSERT);
+    p = a[i].pExpr;
+    /* pCol->szEst = ... // Column size est for SELECT tables never used */
+    pCol->affinity = sqlite3ExprAffinity(p);
+    while( pCol->affinity<=SQLITE_AFF_NONE && pS2->pNext!=0 ){
+      m |= sqlite3ExprDataType(pS2->pEList->a[i].pExpr);
+      pS2 = pS2->pNext;
+      pCol->affinity = sqlite3ExprAffinity(pS2->pEList->a[i].pExpr);
+    }
+    if( pCol->affinity<=SQLITE_AFF_NONE ){
+      pCol->affinity = aff;
+    }
+    if( pCol->affinity>=SQLITE_AFF_TEXT && (pS2->pNext || pS2!=pSelect) ){
+      for(pS2=pS2->pNext; pS2; pS2=pS2->pNext){
+        m |= sqlite3ExprDataType(pS2->pEList->a[i].pExpr);
+      }
+      if( pCol->affinity==SQLITE_AFF_TEXT && (m&0x01)!=0 ){
+        pCol->affinity = SQLITE_AFF_BLOB;
+      }else
+      if( pCol->affinity>=SQLITE_AFF_NUMERIC && (m&0x02)!=0 ){
+        pCol->affinity = SQLITE_AFF_BLOB;
+      }
+      if( pCol->affinity>=SQLITE_AFF_NUMERIC && p->op==TK_CAST ){
+        pCol->affinity = SQLITE_AFF_FLEXNUM;
+      }
+    }
+    zType = columnType(&sNC, p, 0, 0, 0);
+    if( zType==0 || pCol->affinity!=sqlite3AffinityType(zType, 0) ){
+      if( pCol->affinity==SQLITE_AFF_NUMERIC
+       || pCol->affinity==SQLITE_AFF_FLEXNUM
+      ){
+        zType = "NUM";
+      }else{
+        zType = 0;
+        for(j=1; j<SQLITE_N_STDTYPE; j++){
+          if( sqlite3StdTypeAffinity[j]==pCol->affinity ){
+            zType = sqlite3StdType[j];
+            break;
+          }
+        }
+      }
+    }
+    if( zType ){
+      const i64 k = sqlite3Strlen30(zType);
+      n = sqlite3Strlen30(pCol->zCnName);
+      pCol->zCnName = sqlite3DbReallocOrFree(db, pCol->zCnName, n+k+2);
+      pCol->colFlags &= ~(COLFLAG_HASTYPE|COLFLAG_HASCOLL);
+      if( pCol->zCnName ){
+        memcpy(&pCol->zCnName[n+1], zType, k+1);
+        pCol->colFlags |= COLFLAG_HASTYPE;
+      }
+    }
+    pColl = sqlite3ExprCollSeq(pParse, p);
+    if( pColl ){
+      assert( pTab->pIndex==0 );
+      sqlite3ColumnSetColl(db, pCol, pColl->zName);
+    }
+  }
+  pTab->szTabRow = 1; /* Any non-zero value works */
+}
+
+/*
+** Given a SELECT statement, generate a Table structure that describes
+** the result set of that SELECT.
+*/
+SQLITE_PRIVATE Table *sqlite3ResultSetOfSelect(Parse *pParse, Select *pSelect, char aff){
+  Table *pTab;
+  sqlite3 *db = pParse->db;
+  u64 savedFlags;
+
+  savedFlags = db->flags;
+  db->flags &= ~(u64)SQLITE_FullColNames;
+  db->flags |= SQLITE_ShortColNames;
+  sqlite3SelectPrep(pParse, pSelect, 0);
+  db->flags = savedFlags;
+  if( pParse->nErr ) return 0;
+  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
+  pTab = sqlite3DbMallocZero(db, sizeof(Table) );
+  if( pTab==0 ){
+    return 0;
+  }
+  pTab->nTabRef = 1;
+  pTab->zName = 0;
+  pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
+  sqlite3ColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
+  sqlite3SubqueryColumnTypes(pParse, pTab, pSelect, aff);
+  pTab->iPKey = -1;
+  if( db->mallocFailed ){
+    sqlite3DeleteTable(db, pTab);
+    return 0;
+  }
+  return pTab;
+}
+
+/*
+** Get a VDBE for the given parser context.  Create a new one if necessary.
+** If an error occurs, return NULL and leave a message in pParse.
+*/
+SQLITE_PRIVATE Vdbe *sqlite3GetVdbe(Parse *pParse){
+  if( pParse->pVdbe ){
+    return pParse->pVdbe;
+  }
+  if( pParse->pToplevel==0
+   && OptimizationEnabled(pParse->db,SQLITE_FactorOutConst)
+  ){
+    pParse->okConstFactor = 1;
+  }
+  return sqlite3VdbeCreate(pParse);
+}
+
+
+/*
+** Compute the iLimit and iOffset fields of the SELECT based on the
+** pLimit expressions.  pLimit->pLeft and pLimit->pRight hold the expressions
+** that appear in the original SQL statement after the LIMIT and OFFSET
+** keywords.  Or NULL if those keywords are omitted. iLimit and iOffset
+** are the integer memory register numbers for counters used to compute
+** the limit and offset.  If there is no limit and/or offset, then
+** iLimit and iOffset are negative.
+**
+** This routine changes the values of iLimit and iOffset only if
+** a limit or offset is defined by pLimit->pLeft and pLimit->pRight.  iLimit
+** and iOffset should have been preset to appropriate default values (zero)
+** prior to calling this routine.
+**
+** The iOffset register (if it exists) is initialized to the value
+** of the OFFSET.  The iLimit register is initialized to LIMIT.  Register
+** iOffset+1 is initialized to LIMIT+OFFSET.
+**
+** Only if pLimit->pLeft!=0 do the limit registers get
+** redefined.  The UNION ALL operator uses this property to force
+** the reuse of the same limit and offset registers across multiple
+** SELECT statements.
+*/
+static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
+  Vdbe *v = 0;
+  int iLimit = 0;
+  int iOffset;
+  int n;
+  Expr *pLimit = p->pLimit;
+
+  if( p->iLimit ) return;
+
+  /*
+  ** "LIMIT -1" always shows all rows.  There is some
+  ** controversy about what the correct behavior should be.
+  ** The current implementation interprets "LIMIT 0" to mean
+  ** no rows.
+  */
+  if( pLimit ){
+    assert( pLimit->op==TK_LIMIT );
+    assert( pLimit->pLeft!=0 );
+    p->iLimit = iLimit = ++pParse->nMem;
+    v = sqlite3GetVdbe(pParse);
+    assert( v!=0 );
+    if( sqlite3ExprIsInteger(pLimit->pLeft, &n, pParse) ){
+      sqlite3VdbeAddOp2(v, OP_Integer, n, iLimit);
+      VdbeComment((v, "LIMIT counter"));
+      if( n==0 ){
+        sqlite3VdbeGoto(v, iBreak);
+      }else if( n>=0 && p->nSelectRow>sqlite3LogEst((u64)n) ){
+        p->nSelectRow = sqlite3LogEst((u64)n);
+        p->selFlags |= SF_FixedLimit;
+      }
+    }else{
+      sqlite3ExprCode(pParse, pLimit->pLeft, iLimit);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit); VdbeCoverage(v);
+      VdbeComment((v, "LIMIT counter"));
+      sqlite3VdbeAddOp2(v, OP_IfNot, iLimit, iBreak); VdbeCoverage(v);
+    }
+    if( pLimit->pRight ){
+      p->iOffset = iOffset = ++pParse->nMem;
+      pParse->nMem++;   /* Allocate an extra register for limit+offset */
+      sqlite3ExprCode(pParse, pLimit->pRight, iOffset);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset); VdbeCoverage(v);
+      VdbeComment((v, "OFFSET counter"));
+      sqlite3VdbeAddOp3(v, OP_OffsetLimit, iLimit, iOffset+1, iOffset);
+      VdbeComment((v, "LIMIT+OFFSET"));
+    }
+  }
+}
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** Return the appropriate collating sequence for the iCol-th column of
+** the result set for the compound-select statement "p".  Return NULL if
+** the column has no default collating sequence.
+**
+** The collating sequence for the compound select is taken from the
+** left-most term of the select that has a collating sequence.
+*/
+static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
+  CollSeq *pRet;
+  if( p->pPrior ){
+    pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
+  }else{
+    pRet = 0;
+  }
+  assert( iCol>=0 );
+  /* iCol must be less than p->pEList->nExpr.  Otherwise an error would
+  ** have been thrown during name resolution and we would not have gotten
+  ** this far */
+  if( pRet==0 && ALWAYS(iCol<p->pEList->nExpr) ){
+    pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
+  }
+  return pRet;
+}
+
+/*
+** The select statement passed as the second parameter is a compound SELECT
+** with an ORDER BY clause. This function allocates and returns a KeyInfo
+** structure suitable for implementing the ORDER BY.
+**
+** Space to hold the KeyInfo structure is obtained from malloc. The calling
+** function is responsible for ensuring that this structure is eventually
+** freed.
+*/
+static KeyInfo *multiSelectOrderByKeyInfo(Parse *pParse, Select *p, int nExtra){
+  ExprList *pOrderBy = p->pOrderBy;
+  int nOrderBy = ALWAYS(pOrderBy!=0) ? pOrderBy->nExpr : 0;
+  sqlite3 *db = pParse->db;
+  KeyInfo *pRet = sqlite3KeyInfoAlloc(db, nOrderBy+nExtra, 1);
+  if( pRet ){
+    int i;
+    for(i=0; i<nOrderBy; i++){
+      struct ExprList_item *pItem = &pOrderBy->a[i];
+      Expr *pTerm = pItem->pExpr;
+      CollSeq *pColl;
+
+      if( pTerm->flags & EP_Collate ){
+        pColl = sqlite3ExprCollSeq(pParse, pTerm);
+      }else{
+        pColl = multiSelectCollSeq(pParse, p, pItem->u.x.iOrderByCol-1);
+        if( pColl==0 ) pColl = db->pDfltColl;
+        pOrderBy->a[i].pExpr =
+          sqlite3ExprAddCollateString(pParse, pTerm, pColl->zName);
+      }
+      assert( sqlite3KeyInfoIsWriteable(pRet) );
+      pRet->aColl[i] = pColl;
+      pRet->aSortFlags[i] = pOrderBy->a[i].fg.sortFlags;
+    }
+  }
+
+  return pRet;
+}
+
+#ifndef SQLITE_OMIT_CTE
+/*
+** This routine generates VDBE code to compute the content of a WITH RECURSIVE
+** query of the form:
+**
+**   <recursive-table> AS (<setup-query> UNION [ALL] <recursive-query>)
+**                         \___________/             \_______________/
+**                           p->pPrior                      p
+**
+**
+** There is exactly one reference to the recursive-table in the FROM clause
+** of recursive-query, marked with the SrcList->a[].fg.isRecursive flag.
+**
+** The setup-query runs once to generate an initial set of rows that go
+** into a Queue table.  Rows are extracted from the Queue table one by
+** one.  Each row extracted from Queue is output to pDest.  Then the single
+** extracted row (now in the iCurrent table) becomes the content of the
+** recursive-table for a recursive-query run.  The output of the recursive-query
+** is added back into the Queue table.  Then another row is extracted from Queue
+** and the iteration continues until the Queue table is empty.
+**
+** If the compound query operator is UNION then no duplicate rows are ever
+** inserted into the Queue table.  The iDistinct table keeps a copy of all rows
+** that have ever been inserted into Queue and causes duplicates to be
+** discarded.  If the operator is UNION ALL, then duplicates are allowed.
+**
+** If the query has an ORDER BY, then entries in the Queue table are kept in
+** ORDER BY order and the first entry is extracted for each cycle.  Without
+** an ORDER BY, the Queue table is just a FIFO.
+**
+** If a LIMIT clause is provided, then the iteration stops after LIMIT rows
+** have been output to pDest.  A LIMIT of zero means to output no rows and a
+** negative LIMIT means to output all rows.  If there is also an OFFSET clause
+** with a positive value, then the first OFFSET outputs are discarded rather
+** than being sent to pDest.  The LIMIT count does not begin until after OFFSET
+** rows have been skipped.
+*/
+static void generateWithRecursiveQuery(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The recursive SELECT to be coded */
+  SelectDest *pDest     /* What to do with query results */
+){
+  SrcList *pSrc = p->pSrc;      /* The FROM clause of the recursive query */
+  int nCol = p->pEList->nExpr;  /* Number of columns in the recursive table */
+  Vdbe *v = pParse->pVdbe;      /* The prepared statement under construction */
+  Select *pSetup;               /* The setup query */
+  Select *pFirstRec;            /* Left-most recursive term */
+  int addrTop;                  /* Top of the loop */
+  int addrCont, addrBreak;      /* CONTINUE and BREAK addresses */
+  int iCurrent = 0;             /* The Current table */
+  int regCurrent;               /* Register holding Current table */
+  int iQueue;                   /* The Queue table */
+  int iDistinct = 0;            /* To ensure unique results if UNION */
+  int eDest = SRT_Fifo;         /* How to write to Queue */
+  SelectDest destQueue;         /* SelectDest targeting the Queue table */
+  int i;                        /* Loop counter */
+  int rc;                       /* Result code */
+  ExprList *pOrderBy;           /* The ORDER BY clause */
+  Expr *pLimit;                 /* Saved LIMIT and OFFSET */
+  int regLimit, regOffset;      /* Registers used by LIMIT and OFFSET */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( p->pWin ){
+    sqlite3ErrorMsg(pParse, "cannot use window functions in recursive queries");
+    return;
+  }
+#endif
+
+  /* Obtain authorization to do a recursive query */
+  if( sqlite3AuthCheck(pParse, SQLITE_RECURSIVE, 0, 0, 0) ) return;
+
+  /* Process the LIMIT and OFFSET clauses, if they exist */
+  addrBreak = sqlite3VdbeMakeLabel(pParse);
+  p->nSelectRow = 320;  /* 4 billion rows */
+  computeLimitRegisters(pParse, p, addrBreak);
+  pLimit = p->pLimit;
+  regLimit = p->iLimit;
+  regOffset = p->iOffset;
+  p->pLimit = 0;
+  p->iLimit = p->iOffset = 0;
+  pOrderBy = p->pOrderBy;
+
+  /* Locate the cursor number of the Current table */
+  for(i=0; ALWAYS(i<pSrc->nSrc); i++){
+    if( pSrc->a[i].fg.isRecursive ){
+      iCurrent = pSrc->a[i].iCursor;
+      break;
+    }
+  }
+
+  /* Allocate cursors numbers for Queue and Distinct.  The cursor number for
+  ** the Distinct table must be exactly one greater than Queue in order
+  ** for the SRT_DistFifo and SRT_DistQueue destinations to work. */
+  iQueue = pParse->nTab++;
+  if( p->op==TK_UNION ){
+    eDest = pOrderBy ? SRT_DistQueue : SRT_DistFifo;
+    iDistinct = pParse->nTab++;
+  }else{
+    eDest = pOrderBy ? SRT_Queue : SRT_Fifo;
+  }
+  sqlite3SelectDestInit(&destQueue, eDest, iQueue);
+
+  /* Allocate cursors for Current, Queue, and Distinct. */
+  regCurrent = ++pParse->nMem;
+  sqlite3VdbeAddOp3(v, OP_OpenPseudo, iCurrent, regCurrent, nCol);
+  if( pOrderBy ){
+    KeyInfo *pKeyInfo = multiSelectOrderByKeyInfo(pParse, p, 1);
+    sqlite3VdbeAddOp4(v, OP_OpenEphemeral, iQueue, pOrderBy->nExpr+2, 0,
+                      (char*)pKeyInfo, P4_KEYINFO);
+    destQueue.pOrderBy = pOrderBy;
+  }else{
+    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iQueue, nCol);
+  }
+  VdbeComment((v, "Queue table"));
+  if( iDistinct ){
+    p->addrOpenEphm[0] = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iDistinct, 0);
+    p->selFlags |= SF_UsesEphemeral;
+  }
+
+  /* Detach the ORDER BY clause from the compound SELECT */
+  p->pOrderBy = 0;
+
+  /* Figure out how many elements of the compound SELECT are part of the
+  ** recursive query.  Make sure no recursive elements use aggregate
+  ** functions.  Mark the recursive elements as UNION ALL even if they
+  ** are really UNION because the distinctness will be enforced by the
+  ** iDistinct table.  pFirstRec is left pointing to the left-most
+  ** recursive term of the CTE.
+  */
+  for(pFirstRec=p; ALWAYS(pFirstRec!=0); pFirstRec=pFirstRec->pPrior){
+    if( pFirstRec->selFlags & SF_Aggregate ){
+      sqlite3ErrorMsg(pParse, "recursive aggregate queries not supported");
+      goto end_of_recursive_query;
+    }
+    pFirstRec->op = TK_ALL;
+    if( (pFirstRec->pPrior->selFlags & SF_Recursive)==0 ) break;
+  }
+
+  /* Store the results of the setup-query in Queue. */
+  pSetup = pFirstRec->pPrior;
+  pSetup->pNext = 0;
+  ExplainQueryPlan((pParse, 1, "SETUP"));
+  rc = sqlite3Select(pParse, pSetup, &destQueue);
+  pSetup->pNext = p;
+  if( rc ) goto end_of_recursive_query;
+
+  /* Find the next row in the Queue and output that row */
+  addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iQueue, addrBreak); VdbeCoverage(v);
+
+  /* Transfer the next row in Queue over to Current */
+  sqlite3VdbeAddOp1(v, OP_NullRow, iCurrent); /* To reset column cache */
+  if( pOrderBy ){
+    sqlite3VdbeAddOp3(v, OP_Column, iQueue, pOrderBy->nExpr+1, regCurrent);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_RowData, iQueue, regCurrent);
+  }
+  sqlite3VdbeAddOp1(v, OP_Delete, iQueue);
+
+  /* Output the single row in Current */
+  addrCont = sqlite3VdbeMakeLabel(pParse);
+  codeOffset(v, regOffset, addrCont);
+  selectInnerLoop(pParse, p, iCurrent,
+      0, 0, pDest, addrCont, addrBreak);
+  if( regLimit ){
+    sqlite3VdbeAddOp2(v, OP_DecrJumpZero, regLimit, addrBreak);
+    VdbeCoverage(v);
+  }
+  sqlite3VdbeResolveLabel(v, addrCont);
+
+  /* Execute the recursive SELECT taking the single row in Current as
+  ** the value for the recursive-table. Store the results in the Queue.
+  */
+  pFirstRec->pPrior = 0;
+  ExplainQueryPlan((pParse, 1, "RECURSIVE STEP"));
+  sqlite3Select(pParse, p, &destQueue);
+  assert( pFirstRec->pPrior==0 );
+  pFirstRec->pPrior = pSetup;
+
+  /* Keep running the loop until the Queue is empty */
+  sqlite3VdbeGoto(v, addrTop);
+  sqlite3VdbeResolveLabel(v, addrBreak);
+
+end_of_recursive_query:
+  sqlite3ExprListDelete(pParse->db, p->pOrderBy);
+  p->pOrderBy = pOrderBy;
+  p->pLimit = pLimit;
+  return;
+}
+#endif /* SQLITE_OMIT_CTE */
+
+/* Forward references */
+static int multiSelectOrderBy(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The right-most of SELECTs to be coded */
+  SelectDest *pDest     /* What to do with query results */
+);
+
+/*
+** Handle the special case of a compound-select that originates from a
+** VALUES clause.  By handling this as a special case, we avoid deep
+** recursion, and thus do not need to enforce the SQLITE_LIMIT_COMPOUND_SELECT
+** on a VALUES clause.
+**
+** Because the Select object originates from a VALUES clause:
+**   (1) There is no LIMIT or OFFSET or else there is a LIMIT of exactly 1
+**   (2) All terms are UNION ALL
+**   (3) There is no ORDER BY clause
+**
+** The "LIMIT of exactly 1" case of condition (1) comes about when a VALUES
+** clause occurs within scalar expression (ex: "SELECT (VALUES(1),(2),(3))").
+** The sqlite3CodeSubselect will have added the LIMIT 1 clause in tht case.
+** Since the limit is exactly 1, we only need to evaluate the left-most VALUES.
+*/
+static int multiSelectValues(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The right-most of SELECTs to be coded */
+  SelectDest *pDest     /* What to do with query results */
+){
+  int nRow = 1;
+  int rc = 0;
+  int bShowAll = p->pLimit==0;
+  assert( p->selFlags & SF_MultiValue );
+  do{
+    assert( p->selFlags & SF_Values );
+    assert( p->op==TK_ALL || (p->op==TK_SELECT && p->pPrior==0) );
+    assert( p->pNext==0 || p->pEList->nExpr==p->pNext->pEList->nExpr );
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( p->pWin ) return -1;
+#endif
+    if( p->pPrior==0 ) break;
+    assert( p->pPrior->pNext==p );
+    p = p->pPrior;
+    nRow += bShowAll;
+  }while(1);
+  ExplainQueryPlan((pParse, 0, "SCAN %d CONSTANT ROW%s", nRow,
+                    nRow==1 ? "" : "S"));
+  while( p ){
+    selectInnerLoop(pParse, p, -1, 0, 0, pDest, 1, 1);
+    if( !bShowAll ) break;
+    p->nSelectRow = nRow;
+    p = p->pNext;
+  }
+  return rc;
+}
+
+/*
+** Return true if the SELECT statement which is known to be the recursive
+** part of a recursive CTE still has its anchor terms attached.  If the
+** anchor terms have already been removed, then return false.
+*/
+static int hasAnchor(Select *p){
+  while( p && (p->selFlags & SF_Recursive)!=0 ){ p = p->pPrior; }
+  return p!=0;
+}
+
+/*
+** This routine is called to process a compound query form from
+** two or more separate queries using UNION, UNION ALL, EXCEPT, or
+** INTERSECT
+**
+** "p" points to the right-most of the two queries.  the query on the
+** left is p->pPrior.  The left query could also be a compound query
+** in which case this routine will be called recursively.
+**
+** The results of the total query are to be written into a destination
+** of type eDest with parameter iParm.
+**
+** Example 1:  Consider a three-way compound SQL statement.
+**
+**     SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
+**
+** This statement is parsed up as follows:
+**
+**     SELECT c FROM t3
+**      |
+**      `----->  SELECT b FROM t2
+**                |
+**                `------>  SELECT a FROM t1
+**
+** The arrows in the diagram above represent the Select.pPrior pointer.
+** So if this routine is called with p equal to the t3 query, then
+** pPrior will be the t2 query.  p->op will be TK_UNION in this case.
+**
+** Notice that because of the way SQLite parses compound SELECTs, the
+** individual selects always group from left to right.
+*/
+static int multiSelect(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The right-most of SELECTs to be coded */
+  SelectDest *pDest     /* What to do with query results */
+){
+  int rc = SQLITE_OK;   /* Success code from a subroutine */
+  Select *pPrior;       /* Another SELECT immediately to our left */
+  Vdbe *v;              /* Generate code to this VDBE */
+  SelectDest dest;      /* Alternative data destination */
+  Select *pDelete = 0;  /* Chain of simple selects to delete */
+  sqlite3 *db;          /* Database connection */
+
+  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
+  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
+  */
+  assert( p && p->pPrior );  /* Calling function guarantees this much */
+  assert( (p->selFlags & SF_Recursive)==0 || p->op==TK_ALL || p->op==TK_UNION );
+  assert( p->selFlags & SF_Compound );
+  db = pParse->db;
+  pPrior = p->pPrior;
+  dest = *pDest;
+  assert( pPrior->pOrderBy==0 );
+  assert( pPrior->pLimit==0 );
+
+  v = sqlite3GetVdbe(pParse);
+  assert( v!=0 );  /* The VDBE already created by calling function */
+
+  /* Create the destination temporary table if necessary
+  */
+  if( dest.eDest==SRT_EphemTab ){
+    assert( p->pEList );
+    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iSDParm, p->pEList->nExpr);
+    dest.eDest = SRT_Table;
+  }
+
+  /* Special handling for a compound-select that originates as a VALUES clause.
+  */
+  if( p->selFlags & SF_MultiValue ){
+    rc = multiSelectValues(pParse, p, &dest);
+    if( rc>=0 ) goto multi_select_end;
+    rc = SQLITE_OK;
+  }
+
+  /* Make sure all SELECTs in the statement have the same number of elements
+  ** in their result sets.
+  */
+  assert( p->pEList && pPrior->pEList );
+  assert( p->pEList->nExpr==pPrior->pEList->nExpr );
+
+#ifndef SQLITE_OMIT_CTE
+  if( (p->selFlags & SF_Recursive)!=0 && hasAnchor(p) ){
+    generateWithRecursiveQuery(pParse, p, &dest);
+  }else
+#endif
+
+  /* Compound SELECTs that have an ORDER BY clause are handled separately.
+  */
+  if( p->pOrderBy ){
+    return multiSelectOrderBy(pParse, p, pDest);
+  }else{
+
+#ifndef SQLITE_OMIT_EXPLAIN
+    if( pPrior->pPrior==0 ){
+      ExplainQueryPlan((pParse, 1, "COMPOUND QUERY"));
+      ExplainQueryPlan((pParse, 1, "LEFT-MOST SUBQUERY"));
+    }
+#endif
+
+    /* Generate code for the left and right SELECT statements.
+    */
+    switch( p->op ){
+      case TK_ALL: {
+        int addr = 0;
+        int nLimit = 0;  /* Initialize to suppress harmless compiler warning */
+        assert( !pPrior->pLimit );
+        pPrior->iLimit = p->iLimit;
+        pPrior->iOffset = p->iOffset;
+        pPrior->pLimit = p->pLimit;
+        TREETRACE(0x200, pParse, p, ("multiSelect UNION ALL left...\n"));
+        rc = sqlite3Select(pParse, pPrior, &dest);
+        pPrior->pLimit = 0;
+        if( rc ){
+          goto multi_select_end;
+        }
+        p->pPrior = 0;
+        p->iLimit = pPrior->iLimit;
+        p->iOffset = pPrior->iOffset;
+        if( p->iLimit ){
+          addr = sqlite3VdbeAddOp1(v, OP_IfNot, p->iLimit); VdbeCoverage(v);
+          VdbeComment((v, "Jump ahead if LIMIT reached"));
+          if( p->iOffset ){
+            sqlite3VdbeAddOp3(v, OP_OffsetLimit,
+                              p->iLimit, p->iOffset+1, p->iOffset);
+          }
+        }
+        ExplainQueryPlan((pParse, 1, "UNION ALL"));
+        TREETRACE(0x200, pParse, p, ("multiSelect UNION ALL right...\n"));
+        rc = sqlite3Select(pParse, p, &dest);
+        testcase( rc!=SQLITE_OK );
+        pDelete = p->pPrior;
+        p->pPrior = pPrior;
+        p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
+        if( p->pLimit
+         && sqlite3ExprIsInteger(p->pLimit->pLeft, &nLimit, pParse)
+         && nLimit>0 && p->nSelectRow > sqlite3LogEst((u64)nLimit)
+        ){
+          p->nSelectRow = sqlite3LogEst((u64)nLimit);
+        }
+        if( addr ){
+          sqlite3VdbeJumpHere(v, addr);
+        }
+        break;
+      }
+      case TK_EXCEPT:
+      case TK_UNION: {
+        int unionTab;    /* Cursor number of the temp table holding result */
+        u8 op = 0;       /* One of the SRT_ operations to apply to self */
+        int priorOp;     /* The SRT_ operation to apply to prior selects */
+        Expr *pLimit;    /* Saved values of p->nLimit  */
+        int addr;
+        SelectDest uniondest;
+
+        testcase( p->op==TK_EXCEPT );
+        testcase( p->op==TK_UNION );
+        priorOp = SRT_Union;
+        if( dest.eDest==priorOp ){
+          /* We can reuse a temporary table generated by a SELECT to our
+          ** right.
+          */
+          assert( p->pLimit==0 );      /* Not allowed on leftward elements */
+          unionTab = dest.iSDParm;
+        }else{
+          /* We will need to create our own temporary table to hold the
+          ** intermediate results.
+          */
+          unionTab = pParse->nTab++;
+          assert( p->pOrderBy==0 );
+          addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
+          assert( p->addrOpenEphm[0] == -1 );
+          p->addrOpenEphm[0] = addr;
+          findRightmost(p)->selFlags |= SF_UsesEphemeral;
+          assert( p->pEList );
+        }
+
+
+        /* Code the SELECT statements to our left
+        */
+        assert( !pPrior->pOrderBy );
+        sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
+        TREETRACE(0x200, pParse, p, ("multiSelect EXCEPT/UNION left...\n"));
+        rc = sqlite3Select(pParse, pPrior, &uniondest);
+        if( rc ){
+          goto multi_select_end;
+        }
+
+        /* Code the current SELECT statement
+        */
+        if( p->op==TK_EXCEPT ){
+          op = SRT_Except;
+        }else{
+          assert( p->op==TK_UNION );
+          op = SRT_Union;
+        }
+        p->pPrior = 0;
+        pLimit = p->pLimit;
+        p->pLimit = 0;
+        uniondest.eDest = op;
+        ExplainQueryPlan((pParse, 1, "%s USING TEMP B-TREE",
+                          sqlite3SelectOpName(p->op)));
+        TREETRACE(0x200, pParse, p, ("multiSelect EXCEPT/UNION right...\n"));
+        rc = sqlite3Select(pParse, p, &uniondest);
+        testcase( rc!=SQLITE_OK );
+        assert( p->pOrderBy==0 );
+        pDelete = p->pPrior;
+        p->pPrior = pPrior;
+        p->pOrderBy = 0;
+        if( p->op==TK_UNION ){
+          p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
+        }
+        sqlite3ExprDelete(db, p->pLimit);
+        p->pLimit = pLimit;
+        p->iLimit = 0;
+        p->iOffset = 0;
+
+        /* Convert the data in the temporary table into whatever form
+        ** it is that we currently need.
+        */
+        assert( unionTab==dest.iSDParm || dest.eDest!=priorOp );
+        assert( p->pEList || db->mallocFailed );
+        if( dest.eDest!=priorOp && db->mallocFailed==0 ){
+          int iCont, iBreak, iStart;
+          iBreak = sqlite3VdbeMakeLabel(pParse);
+          iCont = sqlite3VdbeMakeLabel(pParse);
+          computeLimitRegisters(pParse, p, iBreak);
+          sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak); VdbeCoverage(v);
+          iStart = sqlite3VdbeCurrentAddr(v);
+          selectInnerLoop(pParse, p, unionTab,
+                          0, 0, &dest, iCont, iBreak);
+          sqlite3VdbeResolveLabel(v, iCont);
+          sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart); VdbeCoverage(v);
+          sqlite3VdbeResolveLabel(v, iBreak);
+          sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0);
+        }
+        break;
+      }
+      default: assert( p->op==TK_INTERSECT ); {
+        int tab1, tab2;
+        int iCont, iBreak, iStart;
+        Expr *pLimit;
+        int addr;
+        SelectDest intersectdest;
+        int r1;
+
+        /* INTERSECT is different from the others since it requires
+        ** two temporary tables.  Hence it has its own case.  Begin
+        ** by allocating the tables we will need.
+        */
+        tab1 = pParse->nTab++;
+        tab2 = pParse->nTab++;
+        assert( p->pOrderBy==0 );
+
+        addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
+        assert( p->addrOpenEphm[0] == -1 );
+        p->addrOpenEphm[0] = addr;
+        findRightmost(p)->selFlags |= SF_UsesEphemeral;
+        assert( p->pEList );
+
+        /* Code the SELECTs to our left into temporary table "tab1".
+        */
+        sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
+        TREETRACE(0x400, pParse, p, ("multiSelect INTERSECT left...\n"));
+        rc = sqlite3Select(pParse, pPrior, &intersectdest);
+        if( rc ){
+          goto multi_select_end;
+        }
+
+        /* Code the current SELECT into temporary table "tab2"
+        */
+        addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0);
+        assert( p->addrOpenEphm[1] == -1 );
+        p->addrOpenEphm[1] = addr;
+        p->pPrior = 0;
+        pLimit = p->pLimit;
+        p->pLimit = 0;
+        intersectdest.iSDParm = tab2;
+        ExplainQueryPlan((pParse, 1, "%s USING TEMP B-TREE",
+                          sqlite3SelectOpName(p->op)));
+        TREETRACE(0x400, pParse, p, ("multiSelect INTERSECT right...\n"));
+        rc = sqlite3Select(pParse, p, &intersectdest);
+        testcase( rc!=SQLITE_OK );
+        pDelete = p->pPrior;
+        p->pPrior = pPrior;
+        if( p->nSelectRow>pPrior->nSelectRow ){
+          p->nSelectRow = pPrior->nSelectRow;
+        }
+        sqlite3ExprDelete(db, p->pLimit);
+        p->pLimit = pLimit;
+
+        /* Generate code to take the intersection of the two temporary
+        ** tables.
+        */
+        if( rc ) break;
+        assert( p->pEList );
+        iBreak = sqlite3VdbeMakeLabel(pParse);
+        iCont = sqlite3VdbeMakeLabel(pParse);
+        computeLimitRegisters(pParse, p, iBreak);
+        sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak); VdbeCoverage(v);
+        r1 = sqlite3GetTempReg(pParse);
+        iStart = sqlite3VdbeAddOp2(v, OP_RowData, tab1, r1);
+        sqlite3VdbeAddOp4Int(v, OP_NotFound, tab2, iCont, r1, 0);
+        VdbeCoverage(v);
+        sqlite3ReleaseTempReg(pParse, r1);
+        selectInnerLoop(pParse, p, tab1,
+                        0, 0, &dest, iCont, iBreak);
+        sqlite3VdbeResolveLabel(v, iCont);
+        sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart); VdbeCoverage(v);
+        sqlite3VdbeResolveLabel(v, iBreak);
+        sqlite3VdbeAddOp2(v, OP_Close, tab2, 0);
+        sqlite3VdbeAddOp2(v, OP_Close, tab1, 0);
+        break;
+      }
+    }
+
+  #ifndef SQLITE_OMIT_EXPLAIN
+    if( p->pNext==0 ){
+      ExplainQueryPlanPop(pParse);
+    }
+  #endif
+  }
+  if( pParse->nErr ) goto multi_select_end;
+
+  /* Compute collating sequences used by
+  ** temporary tables needed to implement the compound select.
+  ** Attach the KeyInfo structure to all temporary tables.
+  **
+  ** This section is run by the right-most SELECT statement only.
+  ** SELECT statements to the left always skip this part.  The right-most
+  ** SELECT might also skip this part if it has no ORDER BY clause and
+  ** no temp tables are required.
+  */
+  if( p->selFlags & SF_UsesEphemeral ){
+    int i;                        /* Loop counter */
+    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
+    Select *pLoop;                /* For looping through SELECT statements */
+    CollSeq **apColl;             /* For looping through pKeyInfo->aColl[] */
+    int nCol;                     /* Number of columns in result set */
+
+    assert( p->pNext==0 );
+    assert( p->pEList!=0 );
+    nCol = p->pEList->nExpr;
+    pKeyInfo = sqlite3KeyInfoAlloc(db, nCol, 1);
+    if( !pKeyInfo ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto multi_select_end;
+    }
+    for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
+      *apColl = multiSelectCollSeq(pParse, p, i);
+      if( 0==*apColl ){
+        *apColl = db->pDfltColl;
+      }
+    }
+
+    for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
+      for(i=0; i<2; i++){
+        int addr = pLoop->addrOpenEphm[i];
+        if( addr<0 ){
+          /* If [0] is unused then [1] is also unused.  So we can
+          ** always safely abort as soon as the first unused slot is found */
+          assert( pLoop->addrOpenEphm[1]<0 );
+          break;
+        }
+        sqlite3VdbeChangeP2(v, addr, nCol);
+        sqlite3VdbeChangeP4(v, addr, (char*)sqlite3KeyInfoRef(pKeyInfo),
+                            P4_KEYINFO);
+        pLoop->addrOpenEphm[i] = -1;
+      }
+    }
+    sqlite3KeyInfoUnref(pKeyInfo);
+  }
+
+multi_select_end:
+  pDest->iSdst = dest.iSdst;
+  pDest->nSdst = dest.nSdst;
+  pDest->iSDParm2 = dest.iSDParm2;
+  if( pDelete ){
+    sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pDelete);
+  }
+  return rc;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+/*
+** Error message for when two or more terms of a compound select have different
+** size result sets.
+*/
+SQLITE_PRIVATE void sqlite3SelectWrongNumTermsError(Parse *pParse, Select *p){
+  if( p->selFlags & SF_Values ){
+    sqlite3ErrorMsg(pParse, "all VALUES must have the same number of terms");
+  }else{
+    sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
+      " do not have the same number of result columns",
+      sqlite3SelectOpName(p->op));
+  }
+}
+
+/*
+** Code an output subroutine for a coroutine implementation of a
+** SELECT statement.
+**
+** The data to be output is contained in pIn->iSdst.  There are
+** pIn->nSdst columns to be output.  pDest is where the output should
+** be sent.
+**
+** regReturn is the number of the register holding the subroutine
+** return address.
+**
+** If regPrev>0 then it is the first register in a vector that
+** records the previous output.  mem[regPrev] is a flag that is false
+** if there has been no previous output.  If regPrev>0 then code is
+** generated to suppress duplicates.  pKeyInfo is used for comparing
+** keys.
+**
+** If the LIMIT found in p->iLimit is reached, jump immediately to
+** iBreak.
+*/
+static int generateOutputSubroutine(
+  Parse *pParse,          /* Parsing context */
+  Select *p,              /* The SELECT statement */
+  SelectDest *pIn,        /* Coroutine supplying data */
+  SelectDest *pDest,      /* Where to send the data */
+  int regReturn,          /* The return address register */
+  int regPrev,            /* Previous result register.  No uniqueness if 0 */
+  KeyInfo *pKeyInfo,      /* For comparing with previous entry */
+  int iBreak              /* Jump here if we hit the LIMIT */
+){
+  Vdbe *v = pParse->pVdbe;
+  int iContinue;
+  int addr;
+
+  addr = sqlite3VdbeCurrentAddr(v);
+  iContinue = sqlite3VdbeMakeLabel(pParse);
+
+  /* Suppress duplicates for UNION, EXCEPT, and INTERSECT
+  */
+  if( regPrev ){
+    int addr1, addr2;
+    addr1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev); VdbeCoverage(v);
+    addr2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iSdst, regPrev+1, pIn->nSdst,
+                              (char*)sqlite3KeyInfoRef(pKeyInfo), P4_KEYINFO);
+    sqlite3VdbeAddOp3(v, OP_Jump, addr2+2, iContinue, addr2+2); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr1);
+    sqlite3VdbeAddOp3(v, OP_Copy, pIn->iSdst, regPrev+1, pIn->nSdst-1);
+    sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
+  }
+  if( pParse->db->mallocFailed ) return 0;
+
+  /* Suppress the first OFFSET entries if there is an OFFSET clause
+  */
+  codeOffset(v, p->iOffset, iContinue);
+
+  assert( pDest->eDest!=SRT_Exists );
+  assert( pDest->eDest!=SRT_Table );
+  switch( pDest->eDest ){
+    /* Store the result as data using a unique key.
+    */
+    case SRT_EphemTab: {
+      int r1 = sqlite3GetTempReg(pParse);
+      int r2 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iSdst, pIn->nSdst, r1);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iSDParm, r2);
+      sqlite3VdbeAddOp3(v, OP_Insert, pDest->iSDParm, r1, r2);
+      sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+      sqlite3ReleaseTempReg(pParse, r2);
+      sqlite3ReleaseTempReg(pParse, r1);
+      break;
+    }
+
+#ifndef SQLITE_OMIT_SUBQUERY
+    /* If we are creating a set for an "expr IN (SELECT ...)".
+    */
+    case SRT_Set: {
+      int r1;
+      testcase( pIn->nSdst>1 );
+      r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iSdst, pIn->nSdst,
+          r1, pDest->zAffSdst, pIn->nSdst);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pDest->iSDParm, r1,
+                           pIn->iSdst, pIn->nSdst);
+      if( pDest->iSDParm2>0 ){
+        sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pDest->iSDParm2, 0,
+                             pIn->iSdst, pIn->nSdst);
+        ExplainQueryPlan((pParse, 0, "CREATE BLOOM FILTER"));
+      }
+      sqlite3ReleaseTempReg(pParse, r1);
+      break;
+    }
+
+    /* If this is a scalar select that is part of an expression, then
+    ** store the results in the appropriate memory cell and break out
+    ** of the scan loop.  Note that the select might return multiple columns
+    ** if it is the RHS of a row-value IN operator.
+    */
+    case SRT_Mem: {
+      testcase( pIn->nSdst>1 );
+      sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSDParm, pIn->nSdst);
+      /* The LIMIT clause will jump out of the loop for us */
+      break;
+    }
+#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
+
+    /* The results are stored in a sequence of registers
+    ** starting at pDest->iSdst.  Then the co-routine yields.
+    */
+    case SRT_Coroutine: {
+      if( pDest->iSdst==0 ){
+        pDest->iSdst = sqlite3GetTempRange(pParse, pIn->nSdst);
+        pDest->nSdst = pIn->nSdst;
+      }
+      sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSdst, pIn->nSdst);
+      sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
+      break;
+    }
+
+    /* If none of the above, then the result destination must be
+    ** SRT_Output.  This routine is never called with any other
+    ** destination other than the ones handled above or SRT_Output.
+    **
+    ** For SRT_Output, results are stored in a sequence of registers.
+    ** Then the OP_ResultRow opcode is used to cause sqlite3_step() to
+    ** return the next row of result.
+    */
+    default: {
+      assert( pDest->eDest==SRT_Output );
+      sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iSdst, pIn->nSdst);
+      break;
+    }
+  }
+
+  /* Jump to the end of the loop if the LIMIT is reached.
+  */
+  if( p->iLimit ){
+    sqlite3VdbeAddOp2(v, OP_DecrJumpZero, p->iLimit, iBreak); VdbeCoverage(v);
+  }
+
+  /* Generate the subroutine return
+  */
+  sqlite3VdbeResolveLabel(v, iContinue);
+  sqlite3VdbeAddOp1(v, OP_Return, regReturn);
+
+  return addr;
+}
+
+/*
+** Alternative compound select code generator for cases when there
+** is an ORDER BY clause.
+**
+** We assume a query of the following form:
+**
+**      <selectA>  <operator>  <selectB>  ORDER BY <orderbylist>
+**
+** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT.  The idea
+** is to code both <selectA> and <selectB> with the ORDER BY clause as
+** co-routines.  Then run the co-routines in parallel and merge the results
+** into the output.  In addition to the two coroutines (called selectA and
+** selectB) there are 7 subroutines:
+**
+**    outA:    Move the output of the selectA coroutine into the output
+**             of the compound query.
+**
+**    outB:    Move the output of the selectB coroutine into the output
+**             of the compound query.  (Only generated for UNION and
+**             UNION ALL.  EXCEPT and INSERTSECT never output a row that
+**             appears only in B.)
+**
+**    AltB:    Called when there is data from both coroutines and A<B.
+**
+**    AeqB:    Called when there is data from both coroutines and A==B.
+**
+**    AgtB:    Called when there is data from both coroutines and A>B.
+**
+**    EofA:    Called when data is exhausted from selectA.
+**
+**    EofB:    Called when data is exhausted from selectB.
+**
+** The implementation of the latter five subroutines depend on which
+** <operator> is used:
+**
+**
+**             UNION ALL         UNION            EXCEPT          INTERSECT
+**          -------------  -----------------  --------------  -----------------
+**   AltB:   outA, nextA      outA, nextA       outA, nextA         nextA
+**
+**   AeqB:   outA, nextA         nextA             nextA         outA, nextA
+**
+**   AgtB:   outB, nextB      outB, nextB          nextB            nextB
+**
+**   EofA:   outB, nextB      outB, nextB          halt             halt
+**
+**   EofB:   outA, nextA      outA, nextA       outA, nextA         halt
+**
+** In the AltB, AeqB, and AgtB subroutines, an EOF on A following nextA
+** causes an immediate jump to EofA and an EOF on B following nextB causes
+** an immediate jump to EofB.  Within EofA and EofB, and EOF on entry or
+** following nextX causes a jump to the end of the select processing.
+**
+** Duplicate removal in the UNION, EXCEPT, and INTERSECT cases is handled
+** within the output subroutine.  The regPrev register set holds the previously
+** output value.  A comparison is made against this value and the output
+** is skipped if the next results would be the same as the previous.
+**
+** The implementation plan is to implement the two coroutines and seven
+** subroutines first, then put the control logic at the bottom.  Like this:
+**
+**          goto Init
+**     coA: coroutine for left query (A)
+**     coB: coroutine for right query (B)
+**    outA: output one row of A
+**    outB: output one row of B (UNION and UNION ALL only)
+**    EofA: ...
+**    EofB: ...
+**    AltB: ...
+**    AeqB: ...
+**    AgtB: ...
+**    Init: initialize coroutine registers
+**          yield coA
+**          if eof(A) goto EofA
+**          yield coB
+**          if eof(B) goto EofB
+**    Cmpr: Compare A, B
+**          Jump AltB, AeqB, AgtB
+**     End: ...
+**
+** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not
+** actually called using Gosub and they do not Return.  EofA and EofB loop
+** until all data is exhausted then jump to the "end" label.  AltB, AeqB,
+** and AgtB jump to either L2 or to one of EofA or EofB.
+*/
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+static int multiSelectOrderBy(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The right-most of SELECTs to be coded */
+  SelectDest *pDest     /* What to do with query results */
+){
+  int i, j;             /* Loop counters */
+  Select *pPrior;       /* Another SELECT immediately to our left */
+  Select *pSplit;       /* Left-most SELECT in the right-hand group */
+  int nSelect;          /* Number of SELECT statements in the compound */
+  Vdbe *v;              /* Generate code to this VDBE */
+  SelectDest destA;     /* Destination for coroutine A */
+  SelectDest destB;     /* Destination for coroutine B */
+  int regAddrA;         /* Address register for select-A coroutine */
+  int regAddrB;         /* Address register for select-B coroutine */
+  int addrSelectA;      /* Address of the select-A coroutine */
+  int addrSelectB;      /* Address of the select-B coroutine */
+  int regOutA;          /* Address register for the output-A subroutine */
+  int regOutB;          /* Address register for the output-B subroutine */
+  int addrOutA;         /* Address of the output-A subroutine */
+  int addrOutB = 0;     /* Address of the output-B subroutine */
+  int addrEofA;         /* Address of the select-A-exhausted subroutine */
+  int addrEofA_noB;     /* Alternate addrEofA if B is uninitialized */
+  int addrEofB;         /* Address of the select-B-exhausted subroutine */
+  int addrAltB;         /* Address of the A<B subroutine */
+  int addrAeqB;         /* Address of the A==B subroutine */
+  int addrAgtB;         /* Address of the A>B subroutine */
+  int regLimitA;        /* Limit register for select-A */
+  int regLimitB;        /* Limit register for select-A */
+  int regPrev;          /* A range of registers to hold previous output */
+  int savedLimit;       /* Saved value of p->iLimit */
+  int savedOffset;      /* Saved value of p->iOffset */
+  int labelCmpr;        /* Label for the start of the merge algorithm */
+  int labelEnd;         /* Label for the end of the overall SELECT stmt */
+  int addr1;            /* Jump instructions that get retargeted */
+  int op;               /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
+  KeyInfo *pKeyDup = 0; /* Comparison information for duplicate removal */
+  KeyInfo *pKeyMerge;   /* Comparison information for merging rows */
+  sqlite3 *db;          /* Database connection */
+  ExprList *pOrderBy;   /* The ORDER BY clause */
+  int nOrderBy;         /* Number of terms in the ORDER BY clause */
+  u32 *aPermute;        /* Mapping from ORDER BY terms to result set columns */
+
+  assert( p->pOrderBy!=0 );
+  assert( pKeyDup==0 ); /* "Managed" code needs this.  Ticket #3382. */
+  db = pParse->db;
+  v = pParse->pVdbe;
+  assert( v!=0 );       /* Already thrown the error if VDBE alloc failed */
+  labelEnd = sqlite3VdbeMakeLabel(pParse);
+  labelCmpr = sqlite3VdbeMakeLabel(pParse);
+
+
+  /* Patch up the ORDER BY clause
+  */
+  op = p->op;
+  assert( p->pPrior->pOrderBy==0 );
+  pOrderBy = p->pOrderBy;
+  assert( pOrderBy );
+  nOrderBy = pOrderBy->nExpr;
+
+  /* For operators other than UNION ALL we have to make sure that
+  ** the ORDER BY clause covers every term of the result set.  Add
+  ** terms to the ORDER BY clause as necessary.
+  */
+  if( op!=TK_ALL ){
+    for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){
+      struct ExprList_item *pItem;
+      for(j=0, pItem=pOrderBy->a; j<nOrderBy; j++, pItem++){
+        assert( pItem!=0 );
+        assert( pItem->u.x.iOrderByCol>0 );
+        if( pItem->u.x.iOrderByCol==i ) break;
+      }
+      if( j==nOrderBy ){
+        Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
+        if( pNew==0 ) return SQLITE_NOMEM_BKPT;
+        pNew->flags |= EP_IntValue;
+        pNew->u.iValue = i;
+        p->pOrderBy = pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew);
+        if( pOrderBy ) pOrderBy->a[nOrderBy++].u.x.iOrderByCol = (u16)i;
+      }
+    }
+  }
+
+  /* Compute the comparison permutation and keyinfo that is used with
+  ** the permutation used to determine if the next
+  ** row of results comes from selectA or selectB.  Also add explicit
+  ** collations to the ORDER BY clause terms so that when the subqueries
+  ** to the right and the left are evaluated, they use the correct
+  ** collation.
+  */
+  aPermute = sqlite3DbMallocRawNN(db, sizeof(u32)*(nOrderBy + 1));
+  if( aPermute ){
+    struct ExprList_item *pItem;
+    aPermute[0] = nOrderBy;
+    for(i=1, pItem=pOrderBy->a; i<=nOrderBy; i++, pItem++){
+      assert( pItem!=0 );
+      assert( pItem->u.x.iOrderByCol>0 );
+      assert( pItem->u.x.iOrderByCol<=p->pEList->nExpr );
+      aPermute[i] = pItem->u.x.iOrderByCol - 1;
+    }
+    pKeyMerge = multiSelectOrderByKeyInfo(pParse, p, 1);
+  }else{
+    pKeyMerge = 0;
+  }
+
+  /* Allocate a range of temporary registers and the KeyInfo needed
+  ** for the logic that removes duplicate result rows when the
+  ** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL).
+  */
+  if( op==TK_ALL ){
+    regPrev = 0;
+  }else{
+    int nExpr = p->pEList->nExpr;
+    assert( nOrderBy>=nExpr || db->mallocFailed );
+    regPrev = pParse->nMem+1;
+    pParse->nMem += nExpr+1;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev);
+    pKeyDup = sqlite3KeyInfoAlloc(db, nExpr, 1);
+    if( pKeyDup ){
+      assert( sqlite3KeyInfoIsWriteable(pKeyDup) );
+      for(i=0; i<nExpr; i++){
+        pKeyDup->aColl[i] = multiSelectCollSeq(pParse, p, i);
+        pKeyDup->aSortFlags[i] = 0;
+      }
+    }
+  }
+
+  /* Separate the left and the right query from one another
+  */
+  nSelect = 1;
+  if( (op==TK_ALL || op==TK_UNION)
+   && OptimizationEnabled(db, SQLITE_BalancedMerge)
+  ){
+    for(pSplit=p; pSplit->pPrior!=0 && pSplit->op==op; pSplit=pSplit->pPrior){
+      nSelect++;
+      assert( pSplit->pPrior->pNext==pSplit );
+    }
+  }
+  if( nSelect<=3 ){
+    pSplit = p;
+  }else{
+    pSplit = p;
+    for(i=2; i<nSelect; i+=2){ pSplit = pSplit->pPrior; }
+  }
+  pPrior = pSplit->pPrior;
+  assert( pPrior!=0 );
+  pSplit->pPrior = 0;
+  pPrior->pNext = 0;
+  assert( p->pOrderBy == pOrderBy );
+  assert( pOrderBy!=0 || db->mallocFailed );
+  pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0);
+  sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
+  sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
+
+  /* Compute the limit registers */
+  computeLimitRegisters(pParse, p, labelEnd);
+  if( p->iLimit && op==TK_ALL ){
+    regLimitA = ++pParse->nMem;
+    regLimitB = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit,
+                                  regLimitA);
+    sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB);
+  }else{
+    regLimitA = regLimitB = 0;
+  }
+  sqlite3ExprDelete(db, p->pLimit);
+  p->pLimit = 0;
+
+  regAddrA = ++pParse->nMem;
+  regAddrB = ++pParse->nMem;
+  regOutA = ++pParse->nMem;
+  regOutB = ++pParse->nMem;
+  sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
+  sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);
+
+  ExplainQueryPlan((pParse, 1, "MERGE (%s)", sqlite3SelectOpName(p->op)));
+
+  /* Generate a coroutine to evaluate the SELECT statement to the
+  ** left of the compound operator - the "A" select.
+  */
+  addrSelectA = sqlite3VdbeCurrentAddr(v) + 1;
+  addr1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrA, 0, addrSelectA);
+  VdbeComment((v, "left SELECT"));
+  pPrior->iLimit = regLimitA;
+  ExplainQueryPlan((pParse, 1, "LEFT"));
+  sqlite3Select(pParse, pPrior, &destA);
+  sqlite3VdbeEndCoroutine(v, regAddrA);
+  sqlite3VdbeJumpHere(v, addr1);
+
+  /* Generate a coroutine to evaluate the SELECT statement on
+  ** the right - the "B" select
+  */
+  addrSelectB = sqlite3VdbeCurrentAddr(v) + 1;
+  addr1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrB, 0, addrSelectB);
+  VdbeComment((v, "right SELECT"));
+  savedLimit = p->iLimit;
+  savedOffset = p->iOffset;
+  p->iLimit = regLimitB;
+  p->iOffset = 0;
+  ExplainQueryPlan((pParse, 1, "RIGHT"));
+  sqlite3Select(pParse, p, &destB);
+  p->iLimit = savedLimit;
+  p->iOffset = savedOffset;
+  sqlite3VdbeEndCoroutine(v, regAddrB);
+
+  /* Generate a subroutine that outputs the current row of the A
+  ** select as the next output row of the compound select.
+  */
+  VdbeNoopComment((v, "Output routine for A"));
+  addrOutA = generateOutputSubroutine(pParse,
+                 p, &destA, pDest, regOutA,
+                 regPrev, pKeyDup, labelEnd);
+
+  /* Generate a subroutine that outputs the current row of the B
+  ** select as the next output row of the compound select.
+  */
+  if( op==TK_ALL || op==TK_UNION ){
+    VdbeNoopComment((v, "Output routine for B"));
+    addrOutB = generateOutputSubroutine(pParse,
+                 p, &destB, pDest, regOutB,
+                 regPrev, pKeyDup, labelEnd);
+  }
+  sqlite3KeyInfoUnref(pKeyDup);
+
+  /* Generate a subroutine to run when the results from select A
+  ** are exhausted and only data in select B remains.
+  */
+  if( op==TK_EXCEPT || op==TK_INTERSECT ){
+    addrEofA_noB = addrEofA = labelEnd;
+  }else{
+    VdbeNoopComment((v, "eof-A subroutine"));
+    addrEofA = sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
+    addrEofA_noB = sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, labelEnd);
+                                     VdbeCoverage(v);
+    sqlite3VdbeGoto(v, addrEofA);
+    p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
+  }
+
+  /* Generate a subroutine to run when the results from select B
+  ** are exhausted and only data in select A remains.
+  */
+  if( op==TK_INTERSECT ){
+    addrEofB = addrEofA;
+    if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
+  }else{
+    VdbeNoopComment((v, "eof-B subroutine"));
+    addrEofB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
+    sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, labelEnd); VdbeCoverage(v);
+    sqlite3VdbeGoto(v, addrEofB);
+  }
+
+  /* Generate code to handle the case of A<B
+  */
+  VdbeNoopComment((v, "A-lt-B subroutine"));
+  addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
+  sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA); VdbeCoverage(v);
+  sqlite3VdbeGoto(v, labelCmpr);
+
+  /* Generate code to handle the case of A==B
+  */
+  if( op==TK_ALL ){
+    addrAeqB = addrAltB;
+  }else if( op==TK_INTERSECT ){
+    addrAeqB = addrAltB;
+    addrAltB++;
+  }else{
+    VdbeNoopComment((v, "A-eq-B subroutine"));
+    addrAeqB =
+    sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA); VdbeCoverage(v);
+    sqlite3VdbeGoto(v, labelCmpr);
+  }
+
+  /* Generate code to handle the case of A>B
+  */
+  VdbeNoopComment((v, "A-gt-B subroutine"));
+  addrAgtB = sqlite3VdbeCurrentAddr(v);
+  if( op==TK_ALL || op==TK_UNION ){
+    sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
+  }
+  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB); VdbeCoverage(v);
+  sqlite3VdbeGoto(v, labelCmpr);
+
+  /* This code runs once to initialize everything.
+  */
+  sqlite3VdbeJumpHere(v, addr1);
+  sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA_noB); VdbeCoverage(v);
+  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB); VdbeCoverage(v);
+
+  /* Implement the main merge loop
+  */
+  sqlite3VdbeResolveLabel(v, labelCmpr);
+  sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
+  sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy,
+                         (char*)pKeyMerge, P4_KEYINFO);
+  sqlite3VdbeChangeP5(v, OPFLAG_PERMUTE);
+  sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB); VdbeCoverage(v);
+
+  /* Jump to the this point in order to terminate the query.
+  */
+  sqlite3VdbeResolveLabel(v, labelEnd);
+
+  /* Make arrangements to free the 2nd and subsequent arms of the compound
+  ** after the parse has finished */
+  if( pSplit->pPrior ){
+    sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pSplit->pPrior);
+  }
+  pSplit->pPrior = pPrior;
+  pPrior->pNext = pSplit;
+  sqlite3ExprListDelete(db, pPrior->pOrderBy);
+  pPrior->pOrderBy = 0;
+
+  /*** TBD:  Insert subroutine calls to close cursors on incomplete
+  **** subqueries ****/
+  ExplainQueryPlanPop(pParse);
+  return pParse->nErr!=0;
+}
+#endif
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+
+/* An instance of the SubstContext object describes an substitution edit
+** to be performed on a parse tree.
+**
+** All references to columns in table iTable are to be replaced by corresponding
+** expressions in pEList.
+**
+** ## About "isOuterJoin":
+**
+** The isOuterJoin column indicates that the replacement will occur into a
+** position in the parent that NULL-able due to an OUTER JOIN.  Either the
+** target slot in the parent is the right operand of a LEFT JOIN, or one of
+** the left operands of a RIGHT JOIN.  In either case, we need to potentially
+** bypass the substituted expression with OP_IfNullRow.
+**
+** Suppose the original expression is an integer constant. Even though the table
+** has the nullRow flag set, because the expression is an integer constant,
+** it will not be NULLed out.  So instead, we insert an OP_IfNullRow opcode
+** that checks to see if the nullRow flag is set on the table.  If the nullRow
+** flag is set, then the value in the register is set to NULL and the original
+** expression is bypassed.  If the nullRow flag is not set, then the original
+** expression runs to populate the register.
+**
+** Example where this is needed:
+**
+**      CREATE TABLE t1(a INTEGER PRIMARY KEY, b INT);
+**      CREATE TABLE t2(x INT UNIQUE);
+**
+**      SELECT a,b,m,x FROM t1 LEFT JOIN (SELECT 59 AS m,x FROM t2) ON b=x;
+**
+** When the subquery on the right side of the LEFT JOIN is flattened, we
+** have to add OP_IfNullRow in front of the OP_Integer that implements the
+** "m" value of the subquery so that a NULL will be loaded instead of 59
+** when processing a non-matched row of the left.
+*/
+typedef struct SubstContext {
+  Parse *pParse;            /* The parsing context */
+  int iTable;               /* Replace references to this table */
+  int iNewTable;            /* New table number */
+  int isOuterJoin;          /* Add TK_IF_NULL_ROW opcodes on each replacement */
+  ExprList *pEList;         /* Replacement expressions */
+  ExprList *pCList;         /* Collation sequences for replacement expr */
+} SubstContext;
+
+/* Forward Declarations */
+static void substExprList(SubstContext*, ExprList*);
+static void substSelect(SubstContext*, Select*, int);
+
+/*
+** Scan through the expression pExpr.  Replace every reference to
+** a column in table number iTable with a copy of the iColumn-th
+** entry in pEList.  (But leave references to the ROWID column
+** unchanged.)
+**
+** This routine is part of the flattening procedure.  A subquery
+** whose result set is defined by pEList appears as entry in the
+** FROM clause of a SELECT such that the VDBE cursor assigned to that
+** FORM clause entry is iTable.  This routine makes the necessary
+** changes to pExpr so that it refers directly to the source table
+** of the subquery rather the result set of the subquery.
+*/
+static Expr *substExpr(
+  SubstContext *pSubst,  /* Description of the substitution */
+  Expr *pExpr            /* Expr in which substitution occurs */
+){
+  if( pExpr==0 ) return 0;
+  if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON)
+   && pExpr->w.iJoin==pSubst->iTable
+  ){
+    testcase( ExprHasProperty(pExpr, EP_InnerON) );
+    pExpr->w.iJoin = pSubst->iNewTable;
+  }
+  if( pExpr->op==TK_COLUMN
+   && pExpr->iTable==pSubst->iTable
+   && !ExprHasProperty(pExpr, EP_FixedCol)
+  ){
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+    if( pExpr->iColumn<0 ){
+      pExpr->op = TK_NULL;
+    }else
+#endif
+    {
+      Expr *pNew;
+      int iColumn;
+      Expr *pCopy;
+      Expr ifNullRow;
+      iColumn = pExpr->iColumn;
+      assert( iColumn>=0 );
+      assert( pSubst->pEList!=0 && iColumn<pSubst->pEList->nExpr );
+      assert( pExpr->pRight==0 );
+      pCopy = pSubst->pEList->a[iColumn].pExpr;
+      if( sqlite3ExprIsVector(pCopy) ){
+        sqlite3VectorErrorMsg(pSubst->pParse, pCopy);
+      }else{
+        sqlite3 *db = pSubst->pParse->db;
+        if( pSubst->isOuterJoin
+         && (pCopy->op!=TK_COLUMN || pCopy->iTable!=pSubst->iNewTable)
+        ){
+          memset(&ifNullRow, 0, sizeof(ifNullRow));
+          ifNullRow.op = TK_IF_NULL_ROW;
+          ifNullRow.pLeft = pCopy;
+          ifNullRow.iTable = pSubst->iNewTable;
+          ifNullRow.iColumn = -99;
+          ifNullRow.flags = EP_IfNullRow;
+          pCopy = &ifNullRow;
+        }
+        testcase( ExprHasProperty(pCopy, EP_Subquery) );
+        pNew = sqlite3ExprDup(db, pCopy, 0);
+        if( db->mallocFailed ){
+          sqlite3ExprDelete(db, pNew);
+          return pExpr;
+        }
+        if( pSubst->isOuterJoin ){
+          ExprSetProperty(pNew, EP_CanBeNull);
+        }
+        if( pNew->op==TK_TRUEFALSE ){
+          pNew->u.iValue = sqlite3ExprTruthValue(pNew);
+          pNew->op = TK_INTEGER;
+          ExprSetProperty(pNew, EP_IntValue);
+        }
+
+        /* Ensure that the expression now has an implicit collation sequence,
+        ** just as it did when it was a column of a view or sub-query. */
+        {
+          CollSeq *pNat = sqlite3ExprCollSeq(pSubst->pParse, pNew);
+          CollSeq *pColl = sqlite3ExprCollSeq(pSubst->pParse,
+                pSubst->pCList->a[iColumn].pExpr
+          );
+          if( pNat!=pColl || (pNew->op!=TK_COLUMN && pNew->op!=TK_COLLATE) ){
+            pNew = sqlite3ExprAddCollateString(pSubst->pParse, pNew,
+                (pColl ? pColl->zName : "BINARY")
+            );
+          }
+        }
+        ExprClearProperty(pNew, EP_Collate);
+        if( ExprHasProperty(pExpr,EP_OuterON|EP_InnerON) ){
+          sqlite3SetJoinExpr(pNew, pExpr->w.iJoin,
+                             pExpr->flags & (EP_OuterON|EP_InnerON));
+        }
+        sqlite3ExprDelete(db, pExpr);
+        pExpr = pNew;
+      }
+    }
+  }else{
+    if( pExpr->op==TK_IF_NULL_ROW && pExpr->iTable==pSubst->iTable ){
+      pExpr->iTable = pSubst->iNewTable;
+    }
+    pExpr->pLeft = substExpr(pSubst, pExpr->pLeft);
+    pExpr->pRight = substExpr(pSubst, pExpr->pRight);
+    if( ExprUseXSelect(pExpr) ){
+      substSelect(pSubst, pExpr->x.pSelect, 1);
+    }else{
+      substExprList(pSubst, pExpr->x.pList);
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( ExprHasProperty(pExpr, EP_WinFunc) ){
+      Window *pWin = pExpr->y.pWin;
+      pWin->pFilter = substExpr(pSubst, pWin->pFilter);
+      substExprList(pSubst, pWin->pPartition);
+      substExprList(pSubst, pWin->pOrderBy);
+    }
+#endif
+  }
+  return pExpr;
+}
+static void substExprList(
+  SubstContext *pSubst, /* Description of the substitution */
+  ExprList *pList       /* List to scan and in which to make substitutes */
+){
+  int i;
+  if( pList==0 ) return;
+  for(i=0; i<pList->nExpr; i++){
+    pList->a[i].pExpr = substExpr(pSubst, pList->a[i].pExpr);
+  }
+}
+static void substSelect(
+  SubstContext *pSubst, /* Description of the substitution */
+  Select *p,            /* SELECT statement in which to make substitutions */
+  int doPrior           /* Do substitutes on p->pPrior too */
+){
+  SrcList *pSrc;
+  SrcItem *pItem;
+  int i;
+  if( !p ) return;
+  do{
+    substExprList(pSubst, p->pEList);
+    substExprList(pSubst, p->pGroupBy);
+    substExprList(pSubst, p->pOrderBy);
+    p->pHaving = substExpr(pSubst, p->pHaving);
+    p->pWhere = substExpr(pSubst, p->pWhere);
+    pSrc = p->pSrc;
+    assert( pSrc!=0 );
+    for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
+      if( pItem->fg.isSubquery ){
+        substSelect(pSubst, pItem->u4.pSubq->pSelect, 1);
+      }
+      if( pItem->fg.isTabFunc ){
+        substExprList(pSubst, pItem->u1.pFuncArg);
+      }
+    }
+  }while( doPrior && (p = p->pPrior)!=0 );
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/*
+** pSelect is a SELECT statement and pSrcItem is one item in the FROM
+** clause of that SELECT.
+**
+** This routine scans the entire SELECT statement and recomputes the
+** pSrcItem->colUsed mask.
+*/
+static int recomputeColumnsUsedExpr(Walker *pWalker, Expr *pExpr){
+  SrcItem *pItem;
+  if( pExpr->op!=TK_COLUMN ) return WRC_Continue;
+  pItem = pWalker->u.pSrcItem;
+  if( pItem->iCursor!=pExpr->iTable ) return WRC_Continue;
+  if( pExpr->iColumn<0 ) return WRC_Continue;
+  pItem->colUsed |= sqlite3ExprColUsed(pExpr);
+  return WRC_Continue;
+}
+static void recomputeColumnsUsed(
+  Select *pSelect,                 /* The complete SELECT statement */
+  SrcItem *pSrcItem                /* Which FROM clause item to recompute */
+){
+  Walker w;
+  if( NEVER(pSrcItem->pSTab==0) ) return;
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = recomputeColumnsUsedExpr;
+  w.xSelectCallback = sqlite3SelectWalkNoop;
+  w.u.pSrcItem = pSrcItem;
+  pSrcItem->colUsed = 0;
+  sqlite3WalkSelect(&w, pSelect);
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/*
+** Assign new cursor numbers to each of the items in pSrc. For each
+** new cursor number assigned, set an entry in the aCsrMap[] array
+** to map the old cursor number to the new:
+**
+**     aCsrMap[iOld+1] = iNew;
+**
+** The array is guaranteed by the caller to be large enough for all
+** existing cursor numbers in pSrc.  aCsrMap[0] is the array size.
+**
+** If pSrc contains any sub-selects, call this routine recursively
+** on the FROM clause of each such sub-select, with iExcept set to -1.
+*/
+static void srclistRenumberCursors(
+  Parse *pParse,                  /* Parse context */
+  int *aCsrMap,                   /* Array to store cursor mappings in */
+  SrcList *pSrc,                  /* FROM clause to renumber */
+  int iExcept                     /* FROM clause item to skip */
+){
+  int i;
+  SrcItem *pItem;
+  for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){
+    if( i!=iExcept ){
+      Select *p;
+      assert( pItem->iCursor < aCsrMap[0] );
+      if( !pItem->fg.isRecursive || aCsrMap[pItem->iCursor+1]==0 ){
+        aCsrMap[pItem->iCursor+1] = pParse->nTab++;
+      }
+      pItem->iCursor = aCsrMap[pItem->iCursor+1];
+      if( pItem->fg.isSubquery ){
+        for(p=pItem->u4.pSubq->pSelect; p; p=p->pPrior){
+          srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1);
+        }
+      }
+    }
+  }
+}
+
+/*
+** *piCursor is a cursor number.  Change it if it needs to be mapped.
+*/
+static void renumberCursorDoMapping(Walker *pWalker, int *piCursor){
+  int *aCsrMap = pWalker->u.aiCol;
+  int iCsr = *piCursor;
+  if( iCsr < aCsrMap[0] && aCsrMap[iCsr+1]>0 ){
+    *piCursor = aCsrMap[iCsr+1];
+  }
+}
+
+/*
+** Expression walker callback used by renumberCursors() to update
+** Expr objects to match newly assigned cursor numbers.
+*/
+static int renumberCursorsCb(Walker *pWalker, Expr *pExpr){
+  int op = pExpr->op;
+  if( op==TK_COLUMN || op==TK_IF_NULL_ROW ){
+    renumberCursorDoMapping(pWalker, &pExpr->iTable);
+  }
+  if( ExprHasProperty(pExpr, EP_OuterON) ){
+    renumberCursorDoMapping(pWalker, &pExpr->w.iJoin);
+  }
+  return WRC_Continue;
+}
+
+/*
+** Assign a new cursor number to each cursor in the FROM clause (Select.pSrc)
+** of the SELECT statement passed as the second argument, and to each
+** cursor in the FROM clause of any FROM clause sub-selects, recursively.
+** Except, do not assign a new cursor number to the iExcept'th element in
+** the FROM clause of (*p). Update all expressions and other references
+** to refer to the new cursor numbers.
+**
+** Argument aCsrMap is an array that may be used for temporary working
+** space. Two guarantees are made by the caller:
+**
+**   * the array is larger than the largest cursor number used within the
+**     select statement passed as an argument, and
+**
+**   * the array entries for all cursor numbers that do *not* appear in
+**     FROM clauses of the select statement as described above are
+**     initialized to zero.
+*/
+static void renumberCursors(
+  Parse *pParse,                  /* Parse context */
+  Select *p,                      /* Select to renumber cursors within */
+  int iExcept,                    /* FROM clause item to skip */
+  int *aCsrMap                    /* Working space */
+){
+  Walker w;
+  srclistRenumberCursors(pParse, aCsrMap, p->pSrc, iExcept);
+  memset(&w, 0, sizeof(w));
+  w.u.aiCol = aCsrMap;
+  w.xExprCallback = renumberCursorsCb;
+  w.xSelectCallback = sqlite3SelectWalkNoop;
+  sqlite3WalkSelect(&w, p);
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+/*
+** If pSel is not part of a compound SELECT, return a pointer to its
+** expression list. Otherwise, return a pointer to the expression list
+** of the leftmost SELECT in the compound.
+*/
+static ExprList *findLeftmostExprlist(Select *pSel){
+  while( pSel->pPrior ){
+    pSel = pSel->pPrior;
+  }
+  return pSel->pEList;
+}
+
+/*
+** Return true if any of the result-set columns in the compound query
+** have incompatible affinities on one or more arms of the compound.
+*/
+static int compoundHasDifferentAffinities(Select *p){
+  int ii;
+  ExprList *pList;
+  assert( p!=0 );
+  assert( p->pEList!=0 );
+  assert( p->pPrior!=0 );
+  pList = p->pEList;
+  for(ii=0; ii<pList->nExpr; ii++){
+    char aff;
+    Select *pSub1;
+    assert( pList->a[ii].pExpr!=0 );
+    aff = sqlite3ExprAffinity(pList->a[ii].pExpr);
+    for(pSub1=p->pPrior; pSub1; pSub1=pSub1->pPrior){
+      assert( pSub1->pEList!=0 );
+      assert( pSub1->pEList->nExpr>ii );
+      assert( pSub1->pEList->a[ii].pExpr!=0 );
+      if( sqlite3ExprAffinity(pSub1->pEList->a[ii].pExpr)!=aff ){
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/*
+** This routine attempts to flatten subqueries as a performance optimization.
+** This routine returns 1 if it makes changes and 0 if no flattening occurs.
+**
+** To understand the concept of flattening, consider the following
+** query:
+**
+**     SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
+**
+** The default way of implementing this query is to execute the
+** subquery first and store the results in a temporary table, then
+** run the outer query on that temporary table.  This requires two
+** passes over the data.  Furthermore, because the temporary table
+** has no indices, the WHERE clause on the outer query cannot be
+** optimized.
+**
+** This routine attempts to rewrite queries such as the above into
+** a single flat select, like this:
+**
+**     SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
+**
+** The code generated for this simplification gives the same result
+** but only has to scan the data once.  And because indices might
+** exist on the table t1, a complete scan of the data might be
+** avoided.
+**
+** Flattening is subject to the following constraints:
+**
+**  (**)  We no longer attempt to flatten aggregate subqueries. Was:
+**        The subquery and the outer query cannot both be aggregates.
+**
+**  (**)  We no longer attempt to flatten aggregate subqueries. Was:
+**        (2) If the subquery is an aggregate then
+**        (2a) the outer query must not be a join and
+**        (2b) the outer query must not use subqueries
+**             other than the one FROM-clause subquery that is a candidate
+**             for flattening.  (This is due to ticket [2f7170d73bf9abf80]
+**             from 2015-02-09.)
+**
+**   (3)  If the subquery is the right operand of a LEFT JOIN then
+**        (3a) the subquery may not be a join and
+**        (3b) the FROM clause of the subquery may not contain a virtual
+**             table and
+**        (**) Was: "The outer query may not have a GROUP BY." This case
+**             is now managed correctly
+**        (3d) the outer query may not be DISTINCT.
+**        See also (26) for restrictions on RIGHT JOIN.
+**
+**   (4)  The subquery can not be DISTINCT.
+**
+**  (**)  At one point restrictions (4) and (5) defined a subset of DISTINCT
+**        sub-queries that were excluded from this optimization. Restriction
+**        (4) has since been expanded to exclude all DISTINCT subqueries.
+**
+**  (**)  We no longer attempt to flatten aggregate subqueries.  Was:
+**        If the subquery is aggregate, the outer query may not be DISTINCT.
+**
+**   (7)  The subquery must have a FROM clause.  TODO:  For subqueries without
+**        A FROM clause, consider adding a FROM clause with the special
+**        table sqlite_once that consists of a single row containing a
+**        single NULL.
+**
+**   (8)  If the subquery uses LIMIT then the outer query may not be a join.
+**
+**   (9)  If the subquery uses LIMIT then the outer query may not be aggregate.
+**
+**  (**)  Restriction (10) was removed from the code on 2005-02-05 but we
+**        accidentally carried the comment forward until 2014-09-15.  Original
+**        constraint: "If the subquery is aggregate then the outer query
+**        may not use LIMIT."
+**
+**  (11)  The subquery and the outer query may not both have ORDER BY clauses.
+**
+**  (**)  Not implemented.  Subsumed into restriction (3).  Was previously
+**        a separate restriction deriving from ticket #350.
+**
+**  (13)  The subquery and outer query may not both use LIMIT.
+**
+**  (14)  The subquery may not use OFFSET.
+**
+**  (15)  If the outer query is part of a compound select, then the
+**        subquery may not use LIMIT.
+**        (See ticket #2339 and ticket [02a8e81d44]).
+**
+**  (16)  If the outer query is aggregate, then the subquery may not
+**        use ORDER BY.  (Ticket #2942)  This used to not matter
+**        until we introduced the group_concat() function.
+**
+**  (17)  If the subquery is a compound select, then
+**        (17a) all compound operators must be a UNION ALL, and
+**        (17b) no terms within the subquery compound may be aggregate
+**              or DISTINCT, and
+**        (17c) every term within the subquery compound must have a FROM clause
+**        (17d) the outer query may not be
+**              (17d1) aggregate, or
+**              (17d2) DISTINCT
+**        (17e) the subquery may not contain window functions, and
+**        (17f) the subquery must not be the RHS of a LEFT JOIN.
+**        (17g) either the subquery is the first element of the outer
+**              query or there are no RIGHT or FULL JOINs in any arm
+**              of the subquery.  (This is a duplicate of condition (27b).)
+**        (17h) The corresponding result set expressions in all arms of the
+**              compound must have the same affinity.
+**
+**        The parent and sub-query may contain WHERE clauses. Subject to
+**        rules (11), (13) and (14), they may also contain ORDER BY,
+**        LIMIT and OFFSET clauses.  The subquery cannot use any compound
+**        operator other than UNION ALL because all the other compound
+**        operators have an implied DISTINCT which is disallowed by
+**        restriction (4).
+**
+**        Also, each component of the sub-query must return the same number
+**        of result columns. This is actually a requirement for any compound
+**        SELECT statement, but all the code here does is make sure that no
+**        such (illegal) sub-query is flattened. The caller will detect the
+**        syntax error and return a detailed message.
+**
+**  (18)  If the sub-query is a compound select, then all terms of the
+**        ORDER BY clause of the parent must be copies of a term returned
+**        by the parent query.
+**
+**  (19)  If the subquery uses LIMIT then the outer query may not
+**        have a WHERE clause.
+**
+**  (20)  If the sub-query is a compound select, then it must not use
+**        an ORDER BY clause.  Ticket #3773.  We could relax this constraint
+**        somewhat by saying that the terms of the ORDER BY clause must
+**        appear as unmodified result columns in the outer query.  But we
+**        have other optimizations in mind to deal with that case.
+**
+**  (21)  If the subquery uses LIMIT then the outer query may not be
+**        DISTINCT.  (See ticket [752e1646fc]).
+**
+**  (22)  The subquery may not be a recursive CTE.
+**
+**  (23)  If the outer query is a recursive CTE, then the sub-query may not be
+**        a compound query.  This restriction is because transforming the
+**        parent to a compound query confuses the code that handles
+**        recursive queries in multiSelect().
+**
+**  (**)  We no longer attempt to flatten aggregate subqueries.  Was:
+**        The subquery may not be an aggregate that uses the built-in min() or
+**        or max() functions.  (Without this restriction, a query like:
+**        "SELECT x FROM (SELECT max(y), x FROM t1)" would not necessarily
+**        return the value X for which Y was maximal.)
+**
+**  (25)  If either the subquery or the parent query contains a window
+**        function in the select list or ORDER BY clause, flattening
+**        is not attempted.
+**
+**  (26)  The subquery may not be the right operand of a RIGHT JOIN.
+**        See also (3) for restrictions on LEFT JOIN.
+**
+**  (27)  The subquery may not contain a FULL or RIGHT JOIN unless it
+**        is the first element of the parent query.  Two subcases:
+**        (27a) the subquery is not a compound query.
+**        (27b) the subquery is a compound query and the RIGHT JOIN occurs
+**              in any arm of the compound query.  (See also (17g).)
+**
+**  (28)  The subquery is not a MATERIALIZED CTE.  (This is handled
+**        in the caller before ever reaching this routine.)
+**
+**
+** In this routine, the "p" parameter is a pointer to the outer query.
+** The subquery is p->pSrc->a[iFrom].  isAgg is true if the outer query
+** uses aggregates.
+**
+** If flattening is not attempted, this routine is a no-op and returns 0.
+** If flattening is attempted this routine returns 1.
+**
+** All of the expression analysis must occur on both the outer query and
+** the subquery before this routine runs.
+*/
+static int flattenSubquery(
+  Parse *pParse,       /* Parsing context */
+  Select *p,           /* The parent or outer SELECT statement */
+  int iFrom,           /* Index in p->pSrc->a[] of the inner subquery */
+  int isAgg            /* True if outer SELECT uses aggregate functions */
+){
+  const char *zSavedAuthContext = pParse->zAuthContext;
+  Select *pParent;    /* Current UNION ALL term of the other query */
+  Select *pSub;       /* The inner query or "subquery" */
+  Select *pSub1;      /* Pointer to the rightmost select in sub-query */
+  SrcList *pSrc;      /* The FROM clause of the outer query */
+  SrcList *pSubSrc;   /* The FROM clause of the subquery */
+  int iParent;        /* VDBE cursor number of the pSub result set temp table */
+  int iNewParent = -1;/* Replacement table for iParent */
+  int isOuterJoin = 0; /* True if pSub is the right side of a LEFT JOIN */
+  int i;              /* Loop counter */
+  Expr *pWhere;                    /* The WHERE clause */
+  SrcItem *pSubitem;               /* The subquery */
+  sqlite3 *db = pParse->db;
+  Walker w;                        /* Walker to persist agginfo data */
+  int *aCsrMap = 0;
+
+  /* Check to see if flattening is permitted.  Return 0 if not.
+  */
+  assert( p!=0 );
+  assert( p->pPrior==0 );
+  if( OptimizationDisabled(db, SQLITE_QueryFlattener) ) return 0;
+  pSrc = p->pSrc;
+  assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
+  pSubitem = &pSrc->a[iFrom];
+  iParent = pSubitem->iCursor;
+  assert( pSubitem->fg.isSubquery );
+  pSub = pSubitem->u4.pSubq->pSelect;
+  assert( pSub!=0 );
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( p->pWin || pSub->pWin ) return 0;                  /* Restriction (25) */
+#endif
+
+  pSubSrc = pSub->pSrc;
+  assert( pSubSrc );
+  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
+  ** not arbitrary expressions, we allowed some combining of LIMIT and OFFSET
+  ** because they could be computed at compile-time.  But when LIMIT and OFFSET
+  ** became arbitrary expressions, we were forced to add restrictions (13)
+  ** and (14). */
+  if( pSub->pLimit && p->pLimit ) return 0;              /* Restriction (13) */
+  if( pSub->pLimit && pSub->pLimit->pRight ) return 0;   /* Restriction (14) */
+  if( (p->selFlags & SF_Compound)!=0 && pSub->pLimit ){
+    return 0;                                            /* Restriction (15) */
+  }
+  if( pSubSrc->nSrc==0 ) return 0;                       /* Restriction (7)  */
+  if( pSub->selFlags & SF_Distinct ) return 0;           /* Restriction (4)  */
+  if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){
+     return 0;         /* Restrictions (8)(9) */
+  }
+  if( p->pOrderBy && pSub->pOrderBy ){
+     return 0;                                           /* Restriction (11) */
+  }
+  if( isAgg && pSub->pOrderBy ) return 0;                /* Restriction (16) */
+  if( pSub->pLimit && p->pWhere ) return 0;              /* Restriction (19) */
+  if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
+     return 0;         /* Restriction (21) */
+  }
+  if( pSub->selFlags & (SF_Recursive) ){
+    return 0; /* Restrictions (22) */
+  }
+
+  /*
+  ** If the subquery is the right operand of a LEFT JOIN, then the
+  ** subquery may not be a join itself (3a). Example of why this is not
+  ** allowed:
+  **
+  **         t1 LEFT OUTER JOIN (t2 JOIN t3)
+  **
+  ** If we flatten the above, we would get
+  **
+  **         (t1 LEFT OUTER JOIN t2) JOIN t3
+  **
+  ** which is not at all the same thing.
+  **
+  ** See also tickets #306, #350, and #3300.
+  */
+  if( (pSubitem->fg.jointype & (JT_OUTER|JT_LTORJ))!=0 ){
+    if( pSubSrc->nSrc>1                        /* (3a) */
+     || IsVirtual(pSubSrc->a[0].pSTab)         /* (3b) */
+     || (p->selFlags & SF_Distinct)!=0         /* (3d) */
+     || (pSubitem->fg.jointype & JT_RIGHT)!=0  /* (26) */
+    ){
+      return 0;
+    }
+    isOuterJoin = 1;
+  }
+
+  assert( pSubSrc->nSrc>0 );  /* True by restriction (7) */
+  if( iFrom>0 && (pSubSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
+    return 0;   /* Restriction (27a) */
+  }
+
+  /* Condition (28) is blocked by the caller */
+  assert( !pSubitem->fg.isCte || pSubitem->u2.pCteUse->eM10d!=M10d_Yes );
+
+  /* Restriction (17): If the sub-query is a compound SELECT, then it must
+  ** use only the UNION ALL operator. And none of the simple select queries
+  ** that make up the compound SELECT are allowed to be aggregate or distinct
+  ** queries.
+  */
+  if( pSub->pPrior ){
+    int ii;
+    if( pSub->pOrderBy ){
+      return 0;  /* Restriction (20) */
+    }
+    if( isAgg || (p->selFlags & SF_Distinct)!=0 || isOuterJoin>0 ){
+      return 0; /* (17d1), (17d2), or (17f) */
+    }
+    for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
+      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
+      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
+      assert( pSub->pSrc!=0 );
+      assert( (pSub->selFlags & SF_Recursive)==0 );
+      assert( pSub->pEList->nExpr==pSub1->pEList->nExpr );
+      if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0    /* (17b) */
+       || (pSub1->pPrior && pSub1->op!=TK_ALL)                 /* (17a) */
+       || pSub1->pSrc->nSrc<1                                  /* (17c) */
+#ifndef SQLITE_OMIT_WINDOWFUNC
+       || pSub1->pWin                                          /* (17e) */
+#endif
+      ){
+        return 0;
+      }
+      if( iFrom>0 && (pSub1->pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
+        /* Without this restriction, the JT_LTORJ flag would end up being
+        ** omitted on left-hand tables of the right join that is being
+        ** flattened. */
+        return 0;   /* Restrictions (17g), (27b) */
+      }
+      testcase( pSub1->pSrc->nSrc>1 );
+    }
+
+    /* Restriction (18). */
+    if( p->pOrderBy ){
+      for(ii=0; ii<p->pOrderBy->nExpr; ii++){
+        if( p->pOrderBy->a[ii].u.x.iOrderByCol==0 ) return 0;
+      }
+    }
+
+    /* Restriction (23) */
+    if( (p->selFlags & SF_Recursive) ) return 0;
+
+    /* Restriction (17h) */
+    if( compoundHasDifferentAffinities(pSub) ) return 0;
+
+    if( pSrc->nSrc>1 ){
+      if( pParse->nSelect>500 ) return 0;
+      if( OptimizationDisabled(db, SQLITE_FlttnUnionAll) ) return 0;
+      aCsrMap = sqlite3DbMallocZero(db, ((i64)pParse->nTab+1)*sizeof(int));
+      if( aCsrMap ) aCsrMap[0] = pParse->nTab;
+    }
+  }
+
+  /***** If we reach this point, flattening is permitted. *****/
+  TREETRACE(0x4,pParse,p,("flatten %u.%p from term %d\n",
+                   pSub->selId, pSub, iFrom));
+
+  /* Authorize the subquery */
+  pParse->zAuthContext = pSubitem->zName;
+  TESTONLY(i =) sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0);
+  testcase( i==SQLITE_DENY );
+  pParse->zAuthContext = zSavedAuthContext;
+
+  /* Delete the transient structures associated with the subquery */
+
+  if( ALWAYS(pSubitem->fg.isSubquery) ){
+    pSub1 = sqlite3SubqueryDetach(db, pSubitem);
+  }else{
+    pSub1 = 0;
+  }
+  assert( pSubitem->fg.isSubquery==0 );
+  assert( pSubitem->fg.fixedSchema==0 );
+  sqlite3DbFree(db, pSubitem->zName);
+  sqlite3DbFree(db, pSubitem->zAlias);
+  pSubitem->zName = 0;
+  pSubitem->zAlias = 0;
+  assert( pSubitem->fg.isUsing!=0 || pSubitem->u3.pOn==0 );
+
+  /* If the sub-query is a compound SELECT statement, then (by restrictions
+  ** 17 and 18 above) it must be a UNION ALL and the parent query must
+  ** be of the form:
+  **
+  **     SELECT <expr-list> FROM (<sub-query>) <where-clause>
+  **
+  ** followed by any ORDER BY, LIMIT and/or OFFSET clauses. This block
+  ** creates N-1 copies of the parent query without any ORDER BY, LIMIT or
+  ** OFFSET clauses and joins them to the left-hand-side of the original
+  ** using UNION ALL operators. In this case N is the number of simple
+  ** select statements in the compound sub-query.
+  **
+  ** Example:
+  **
+  **     SELECT a+1 FROM (
+  **        SELECT x FROM tab
+  **        UNION ALL
+  **        SELECT y FROM tab
+  **        UNION ALL
+  **        SELECT abs(z*2) FROM tab2
+  **     ) WHERE a!=5 ORDER BY 1
+  **
+  ** Transformed into:
+  **
+  **     SELECT x+1 FROM tab WHERE x+1!=5
+  **     UNION ALL
+  **     SELECT y+1 FROM tab WHERE y+1!=5
+  **     UNION ALL
+  **     SELECT abs(z*2)+1 FROM tab2 WHERE abs(z*2)+1!=5
+  **     ORDER BY 1
+  **
+  ** We call this the "compound-subquery flattening".
+  */
+  for(pSub=pSub->pPrior; pSub; pSub=pSub->pPrior){
+    Select *pNew;
+    ExprList *pOrderBy = p->pOrderBy;
+    Expr *pLimit = p->pLimit;
+    Select *pPrior = p->pPrior;
+    Table *pItemTab = pSubitem->pSTab;
+    pSubitem->pSTab = 0;
+    p->pOrderBy = 0;
+    p->pPrior = 0;
+    p->pLimit = 0;
+    pNew = sqlite3SelectDup(db, p, 0);
+    p->pLimit = pLimit;
+    p->pOrderBy = pOrderBy;
+    p->op = TK_ALL;
+    pSubitem->pSTab = pItemTab;
+    if( pNew==0 ){
+      p->pPrior = pPrior;
+    }else{
+      pNew->selId = ++pParse->nSelect;
+      if( aCsrMap && ALWAYS(db->mallocFailed==0) ){
+        renumberCursors(pParse, pNew, iFrom, aCsrMap);
+      }
+      pNew->pPrior = pPrior;
+      if( pPrior ) pPrior->pNext = pNew;
+      pNew->pNext = p;
+      p->pPrior = pNew;
+      TREETRACE(0x4,pParse,p,("compound-subquery flattener"
+                              " creates %u as peer\n",pNew->selId));
+    }
+    assert( pSubitem->fg.isSubquery==0 );
+  }
+  sqlite3DbFree(db, aCsrMap);
+  if( db->mallocFailed ){
+    assert( pSubitem->fg.fixedSchema==0 );
+    assert( pSubitem->fg.isSubquery==0 );
+    assert( pSubitem->u4.zDatabase==0 );
+    sqlite3SrcItemAttachSubquery(pParse, pSubitem, pSub1, 0);
+    return 1;
+  }
+
+  /* Defer deleting the Table object associated with the
+  ** subquery until code generation is
+  ** complete, since there may still exist Expr.pTab entries that
+  ** refer to the subquery even after flattening.  Ticket #3346.
+  **
+  ** pSubitem->pTab is always non-NULL by test restrictions and tests above.
+  */
+  if( ALWAYS(pSubitem->pSTab!=0) ){
+    Table *pTabToDel = pSubitem->pSTab;
+    if( pTabToDel->nTabRef==1 ){
+      Parse *pToplevel = sqlite3ParseToplevel(pParse);
+      sqlite3ParserAddCleanup(pToplevel, sqlite3DeleteTableGeneric, pTabToDel);
+      testcase( pToplevel->earlyCleanup );
+    }else{
+      pTabToDel->nTabRef--;
+    }
+    pSubitem->pSTab = 0;
+  }
+
+  /* The following loop runs once for each term in a compound-subquery
+  ** flattening (as described above).  If we are doing a different kind
+  ** of flattening - a flattening other than a compound-subquery flattening -
+  ** then this loop only runs once.
+  **
+  ** This loop moves all of the FROM elements of the subquery into the
+  ** the FROM clause of the outer query.  Before doing this, remember
+  ** the cursor number for the original outer query FROM element in
+  ** iParent.  The iParent cursor will never be used.  Subsequent code
+  ** will scan expressions looking for iParent references and replace
+  ** those references with expressions that resolve to the subquery FROM
+  ** elements we are now copying in.
+  */
+  pSub = pSub1;
+  for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){
+    int nSubSrc;
+    u8 jointype = 0;
+    u8 ltorj = pSrc->a[iFrom].fg.jointype & JT_LTORJ;
+    assert( pSub!=0 );
+    pSubSrc = pSub->pSrc;     /* FROM clause of subquery */
+    nSubSrc = pSubSrc->nSrc;  /* Number of terms in subquery FROM clause */
+    pSrc = pParent->pSrc;     /* FROM clause of the outer query */
+
+    if( pParent==p ){
+      jointype = pSubitem->fg.jointype;     /* First time through the loop */
+    }
+
+    /* The subquery uses a single slot of the FROM clause of the outer
+    ** query.  If the subquery has more than one element in its FROM clause,
+    ** then expand the outer query to make space for it to hold all elements
+    ** of the subquery.
+    **
+    ** Example:
+    **
+    **    SELECT * FROM tabA, (SELECT * FROM sub1, sub2), tabB;
+    **
+    ** The outer query has 3 slots in its FROM clause.  One slot of the
+    ** outer query (the middle slot) is used by the subquery.  The next
+    ** block of code will expand the outer query FROM clause to 4 slots.
+    ** The middle slot is expanded to two slots in order to make space
+    ** for the two elements in the FROM clause of the subquery.
+    */
+    if( nSubSrc>1 ){
+      pSrc = sqlite3SrcListEnlarge(pParse, pSrc, nSubSrc-1,iFrom+1);
+      if( pSrc==0 ) break;
+      pParent->pSrc = pSrc;
+    }
+
+    /* Transfer the FROM clause terms from the subquery into the
+    ** outer query.
+    */
+    iNewParent = pSubSrc->a[0].iCursor;
+    for(i=0; i<nSubSrc; i++){
+      SrcItem *pItem = &pSrc->a[i+iFrom];
+      assert( pItem->fg.isTabFunc==0 );
+      assert( pItem->fg.isSubquery
+           || pItem->fg.fixedSchema
+           || pItem->u4.zDatabase==0 );
+      if( pItem->fg.isUsing ) sqlite3IdListDelete(db, pItem->u3.pUsing);
+      *pItem = pSubSrc->a[i];
+      pItem->fg.jointype |= ltorj;
+      memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
+    }
+    pSrc->a[iFrom].fg.jointype &= JT_LTORJ;
+    pSrc->a[iFrom].fg.jointype |= jointype | ltorj;
+
+    /* Now begin substituting subquery result set expressions for
+    ** references to the iParent in the outer query.
+    **
+    ** Example:
+    **
+    **   SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
+    **   \                     \_____________ subquery __________/          /
+    **    \_____________________ outer query ______________________________/
+    **
+    ** We look at every expression in the outer query and every place we see
+    ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
+    */
+    if( pSub->pOrderBy && (pParent->selFlags & SF_NoopOrderBy)==0 ){
+      /* At this point, any non-zero iOrderByCol values indicate that the
+      ** ORDER BY column expression is identical to the iOrderByCol'th
+      ** expression returned by SELECT statement pSub. Since these values
+      ** do not necessarily correspond to columns in SELECT statement pParent,
+      ** zero them before transferring the ORDER BY clause.
+      **
+      ** Not doing this may cause an error if a subsequent call to this
+      ** function attempts to flatten a compound sub-query into pParent
+      ** (the only way this can happen is if the compound sub-query is
+      ** currently part of pSub->pSrc). See ticket [d11a6e908f].  */
+      ExprList *pOrderBy = pSub->pOrderBy;
+      for(i=0; i<pOrderBy->nExpr; i++){
+        pOrderBy->a[i].u.x.iOrderByCol = 0;
+      }
+      assert( pParent->pOrderBy==0 );
+      pParent->pOrderBy = pOrderBy;
+      pSub->pOrderBy = 0;
+    }
+    pWhere = pSub->pWhere;
+    pSub->pWhere = 0;
+    if( isOuterJoin>0 ){
+      assert( pSubSrc->nSrc==1 );
+      sqlite3SetJoinExpr(pWhere, iNewParent, EP_OuterON);
+    }
+    if( pWhere ){
+      if( pParent->pWhere ){
+        pParent->pWhere = sqlite3PExpr(pParse, TK_AND, pWhere, pParent->pWhere);
+      }else{
+        pParent->pWhere = pWhere;
+      }
+    }
+    if( db->mallocFailed==0 ){
+      SubstContext x;
+      x.pParse = pParse;
+      x.iTable = iParent;
+      x.iNewTable = iNewParent;
+      x.isOuterJoin = isOuterJoin;
+      x.pEList = pSub->pEList;
+      x.pCList = findLeftmostExprlist(pSub);
+      substSelect(&x, pParent, 0);
+    }
+
+    /* The flattened query is a compound if either the inner or the
+    ** outer query is a compound. */
+    pParent->selFlags |= pSub->selFlags & SF_Compound;
+    assert( (pSub->selFlags & SF_Distinct)==0 ); /* restriction (17b) */
+
+    /*
+    ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
+    **
+    ** One is tempted to try to add a and b to combine the limits.  But this
+    ** does not work if either limit is negative.
+    */
+    if( pSub->pLimit ){
+      pParent->pLimit = pSub->pLimit;
+      pSub->pLimit = 0;
+    }
+
+    /* Recompute the SrcItem.colUsed masks for the flattened
+    ** tables. */
+    for(i=0; i<nSubSrc; i++){
+      recomputeColumnsUsed(pParent, &pSrc->a[i+iFrom]);
+    }
+  }
+
+  /* Finally, delete what is left of the subquery and return success.
+  */
+  sqlite3AggInfoPersistWalkerInit(&w, pParse);
+  sqlite3WalkSelect(&w,pSub1);
+  sqlite3SelectDelete(db, pSub1);
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x4 ){
+    TREETRACE(0x4,pParse,p,("After flattening:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+
+  return 1;
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+/*
+** A structure to keep track of all of the column values that are fixed to
+** a known value due to WHERE clause constraints of the form COLUMN=VALUE.
+*/
+typedef struct WhereConst WhereConst;
+struct WhereConst {
+  Parse *pParse;   /* Parsing context */
+  u8 *pOomFault;   /* Pointer to pParse->db->mallocFailed */
+  int nConst;      /* Number for COLUMN=CONSTANT terms */
+  int nChng;       /* Number of times a constant is propagated */
+  int bHasAffBlob; /* At least one column in apExpr[] as affinity BLOB */
+  u32 mExcludeOn;  /* Which ON expressions to exclude from considertion.
+                   ** Either EP_OuterON or EP_InnerON|EP_OuterON */
+  Expr **apExpr;   /* [i*2] is COLUMN and [i*2+1] is VALUE */
+};
+
+/*
+** Add a new entry to the pConst object.  Except, do not add duplicate
+** pColumn entries.  Also, do not add if doing so would not be appropriate.
+**
+** The caller guarantees the pColumn is a column and pValue is a constant.
+** This routine has to do some additional checks before completing the
+** insert.
+*/
+static void constInsert(
+  WhereConst *pConst,  /* The WhereConst into which we are inserting */
+  Expr *pColumn,       /* The COLUMN part of the constraint */
+  Expr *pValue,        /* The VALUE part of the constraint */
+  Expr *pExpr          /* Overall expression: COLUMN=VALUE or VALUE=COLUMN */
+){
+  int i;
+  assert( pColumn->op==TK_COLUMN );
+  assert( sqlite3ExprIsConstant(pConst->pParse, pValue) );
+
+  if( ExprHasProperty(pColumn, EP_FixedCol) ) return;
+  if( sqlite3ExprAffinity(pValue)!=0 ) return;
+  if( !sqlite3IsBinary(sqlite3ExprCompareCollSeq(pConst->pParse,pExpr)) ){
+    return;
+  }
+
+  /* 2018-10-25 ticket [cf5ed20f]
+  ** Make sure the same pColumn is not inserted more than once */
+  for(i=0; i<pConst->nConst; i++){
+    const Expr *pE2 = pConst->apExpr[i*2];
+    assert( pE2->op==TK_COLUMN );
+    if( pE2->iTable==pColumn->iTable
+     && pE2->iColumn==pColumn->iColumn
+    ){
+      return;  /* Already present.  Return without doing anything. */
+    }
+  }
+  if( sqlite3ExprAffinity(pColumn)==SQLITE_AFF_BLOB ){
+    pConst->bHasAffBlob = 1;
+  }
+
+  pConst->nConst++;
+  pConst->apExpr = sqlite3DbReallocOrFree(pConst->pParse->db, pConst->apExpr,
+                         pConst->nConst*2*sizeof(Expr*));
+  if( pConst->apExpr==0 ){
+    pConst->nConst = 0;
+  }else{
+    pConst->apExpr[pConst->nConst*2-2] = pColumn;
+    pConst->apExpr[pConst->nConst*2-1] = pValue;
+  }
+}
+
+/*
+** Find all terms of COLUMN=VALUE or VALUE=COLUMN in pExpr where VALUE
+** is a constant expression and where the term must be true because it
+** is part of the AND-connected terms of the expression.  For each term
+** found, add it to the pConst structure.
+*/
+static void findConstInWhere(WhereConst *pConst, Expr *pExpr){
+  Expr *pRight, *pLeft;
+  if( NEVER(pExpr==0) ) return;
+  if( ExprHasProperty(pExpr, pConst->mExcludeOn) ){
+    testcase( ExprHasProperty(pExpr, EP_OuterON) );
+    testcase( ExprHasProperty(pExpr, EP_InnerON) );
+    return;
+  }
+  if( pExpr->op==TK_AND ){
+    findConstInWhere(pConst, pExpr->pRight);
+    findConstInWhere(pConst, pExpr->pLeft);
+    return;
+  }
+  if( pExpr->op!=TK_EQ ) return;
+  pRight = pExpr->pRight;
+  pLeft = pExpr->pLeft;
+  assert( pRight!=0 );
+  assert( pLeft!=0 );
+  if( pRight->op==TK_COLUMN && sqlite3ExprIsConstant(pConst->pParse, pLeft) ){
+    constInsert(pConst,pRight,pLeft,pExpr);
+  }
+  if( pLeft->op==TK_COLUMN && sqlite3ExprIsConstant(pConst->pParse, pRight) ){
+    constInsert(pConst,pLeft,pRight,pExpr);
+  }
+}
+
+/*
+** This is a helper function for Walker callback propagateConstantExprRewrite().
+**
+** Argument pExpr is a candidate expression to be replaced by a value. If
+** pExpr is equivalent to one of the columns named in pWalker->u.pConst,
+** then overwrite it with the corresponding value. Except, do not do so
+** if argument bIgnoreAffBlob is non-zero and the affinity of pExpr
+** is SQLITE_AFF_BLOB.
+*/
+static int propagateConstantExprRewriteOne(
+  WhereConst *pConst,
+  Expr *pExpr,
+  int bIgnoreAffBlob
+){
+  int i;
+  if( pConst->pOomFault[0] ) return WRC_Prune;
+  if( pExpr->op!=TK_COLUMN ) return WRC_Continue;
+  if( ExprHasProperty(pExpr, EP_FixedCol|pConst->mExcludeOn) ){
+    testcase( ExprHasProperty(pExpr, EP_FixedCol) );
+    testcase( ExprHasProperty(pExpr, EP_OuterON) );
+    testcase( ExprHasProperty(pExpr, EP_InnerON) );
+    return WRC_Continue;
+  }
+  for(i=0; i<pConst->nConst; i++){
+    Expr *pColumn = pConst->apExpr[i*2];
+    if( pColumn==pExpr ) continue;
+    if( pColumn->iTable!=pExpr->iTable ) continue;
+    if( pColumn->iColumn!=pExpr->iColumn ) continue;
+    if( bIgnoreAffBlob && sqlite3ExprAffinity(pColumn)==SQLITE_AFF_BLOB ){
+      break;
+    }
+    /* A match is found.  Add the EP_FixedCol property */
+    pConst->nChng++;
+    ExprClearProperty(pExpr, EP_Leaf);
+    ExprSetProperty(pExpr, EP_FixedCol);
+    assert( pExpr->pLeft==0 );
+    pExpr->pLeft = sqlite3ExprDup(pConst->pParse->db, pConst->apExpr[i*2+1], 0);
+    if( pConst->pParse->db->mallocFailed ) return WRC_Prune;
+    break;
+  }
+  return WRC_Prune;
+}
+
+/*
+** This is a Walker expression callback. pExpr is a node from the WHERE
+** clause of a SELECT statement. This function examines pExpr to see if
+** any substitutions based on the contents of pWalker->u.pConst should
+** be made to pExpr or its immediate children.
+**
+** A substitution is made if:
+**
+**   + pExpr is a column with an affinity other than BLOB that matches
+**     one of the columns in pWalker->u.pConst, or
+**
+**   + pExpr is a binary comparison operator (=, <=, >=, <, >) that
+**     uses an affinity other than TEXT and one of its immediate
+**     children is a column that matches one of the columns in
+**     pWalker->u.pConst.
+*/
+static int propagateConstantExprRewrite(Walker *pWalker, Expr *pExpr){
+  WhereConst *pConst = pWalker->u.pConst;
+  assert( TK_GT==TK_EQ+1 );
+  assert( TK_LE==TK_EQ+2 );
+  assert( TK_LT==TK_EQ+3 );
+  assert( TK_GE==TK_EQ+4 );
+  if( pConst->bHasAffBlob ){
+    if( (pExpr->op>=TK_EQ && pExpr->op<=TK_GE)
+     || pExpr->op==TK_IS
+    ){
+      propagateConstantExprRewriteOne(pConst, pExpr->pLeft, 0);
+      if( pConst->pOomFault[0] ) return WRC_Prune;
+      if( sqlite3ExprAffinity(pExpr->pLeft)!=SQLITE_AFF_TEXT ){
+        propagateConstantExprRewriteOne(pConst, pExpr->pRight, 0);
+      }
+    }
+  }
+  return propagateConstantExprRewriteOne(pConst, pExpr, pConst->bHasAffBlob);
+}
+
+/*
+** The WHERE-clause constant propagation optimization.
+**
+** If the WHERE clause contains terms of the form COLUMN=CONSTANT or
+** CONSTANT=COLUMN that are top-level AND-connected terms that are not
+** part of a ON clause from a LEFT JOIN, then throughout the query
+** replace all other occurrences of COLUMN with CONSTANT.
+**
+** For example, the query:
+**
+**      SELECT * FROM t1, t2, t3 WHERE t1.a=39 AND t2.b=t1.a AND t3.c=t2.b
+**
+** Is transformed into
+**
+**      SELECT * FROM t1, t2, t3 WHERE t1.a=39 AND t2.b=39 AND t3.c=39
+**
+** Return true if any transformations where made and false if not.
+**
+** Implementation note:  Constant propagation is tricky due to affinity
+** and collating sequence interactions.  Consider this example:
+**
+**    CREATE TABLE t1(a INT,b TEXT);
+**    INSERT INTO t1 VALUES(123,'0123');
+**    SELECT * FROM t1 WHERE a=123 AND b=a;
+**    SELECT * FROM t1 WHERE a=123 AND b=123;
+**
+** The two SELECT statements above should return different answers.  b=a
+** is always true because the comparison uses numeric affinity, but b=123
+** is false because it uses text affinity and '0123' is not the same as '123'.
+** To work around this, the expression tree is not actually changed from
+** "b=a" to "b=123" but rather the "a" in "b=a" is tagged with EP_FixedCol
+** and the "123" value is hung off of the pLeft pointer.  Code generator
+** routines know to generate the constant "123" instead of looking up the
+** column value.  Also, to avoid collation problems, this optimization is
+** only attempted if the "a=123" term uses the default BINARY collation.
+**
+** 2021-05-25 forum post 6a06202608: Another troublesome case is...
+**
+**    CREATE TABLE t1(x);
+**    INSERT INTO t1 VALUES(10.0);
+**    SELECT 1 FROM t1 WHERE x=10 AND x LIKE 10;
+**
+** The query should return no rows, because the t1.x value is '10.0' not '10'
+** and '10.0' is not LIKE '10'.  But if we are not careful, the first WHERE
+** term "x=10" will cause the second WHERE term to become "10 LIKE 10",
+** resulting in a false positive.  To avoid this, constant propagation for
+** columns with BLOB affinity is only allowed if the constant is used with
+** operators ==, <=, <, >=, >, or IS in a way that will cause the correct
+** type conversions to occur.  See logic associated with the bHasAffBlob flag
+** for details.
+*/
+static int propagateConstants(
+  Parse *pParse,   /* The parsing context */
+  Select *p        /* The query in which to propagate constants */
+){
+  WhereConst x;
+  Walker w;
+  int nChng = 0;
+  x.pParse = pParse;
+  x.pOomFault = &pParse->db->mallocFailed;
+  do{
+    x.nConst = 0;
+    x.nChng = 0;
+    x.apExpr = 0;
+    x.bHasAffBlob = 0;
+    if( ALWAYS(p->pSrc!=0)
+     && p->pSrc->nSrc>0
+     && (p->pSrc->a[0].fg.jointype & JT_LTORJ)!=0
+    ){
+      /* Do not propagate constants on any ON clause if there is a
+      ** RIGHT JOIN anywhere in the query */
+      x.mExcludeOn = EP_InnerON | EP_OuterON;
+    }else{
+      /* Do not propagate constants through the ON clause of a LEFT JOIN */
+      x.mExcludeOn = EP_OuterON;
+    }
+    findConstInWhere(&x, p->pWhere);
+    if( x.nConst ){
+      memset(&w, 0, sizeof(w));
+      w.pParse = pParse;
+      w.xExprCallback = propagateConstantExprRewrite;
+      w.xSelectCallback = sqlite3SelectWalkNoop;
+      w.xSelectCallback2 = 0;
+      w.walkerDepth = 0;
+      w.u.pConst = &x;
+      sqlite3WalkExpr(&w, p->pWhere);
+      sqlite3DbFree(x.pParse->db, x.apExpr);
+      nChng += x.nChng;
+    }
+  }while( x.nChng );
+  return nChng;
+}
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+# if !defined(SQLITE_OMIT_WINDOWFUNC)
+/*
+** This function is called to determine whether or not it is safe to
+** push WHERE clause expression pExpr down to FROM clause sub-query
+** pSubq, which contains at least one window function. Return 1
+** if it is safe and the expression should be pushed down, or 0
+** otherwise.
+**
+** It is only safe to push the expression down if it consists only
+** of constants and copies of expressions that appear in the PARTITION
+** BY clause of all window function used by the sub-query. It is safe
+** to filter out entire partitions, but not rows within partitions, as
+** this may change the results of the window functions.
+**
+** At the time this function is called it is guaranteed that
+**
+**   * the sub-query uses only one distinct window frame, and
+**   * that the window frame has a PARTITION BY clause.
+*/
+static int pushDownWindowCheck(Parse *pParse, Select *pSubq, Expr *pExpr){
+  assert( pSubq->pWin->pPartition );
+  assert( (pSubq->selFlags & SF_MultiPart)==0 );
+  assert( pSubq->pPrior==0 );
+  return sqlite3ExprIsConstantOrGroupBy(pParse, pExpr, pSubq->pWin->pPartition);
+}
+# endif /* SQLITE_OMIT_WINDOWFUNC */
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/*
+** Make copies of relevant WHERE clause terms of the outer query into
+** the WHERE clause of subquery.  Example:
+**
+**    SELECT * FROM (SELECT a AS x, c-d AS y FROM t1) WHERE x=5 AND y=10;
+**
+** Transformed into:
+**
+**    SELECT * FROM (SELECT a AS x, c-d AS y FROM t1 WHERE a=5 AND c-d=10)
+**     WHERE x=5 AND y=10;
+**
+** The hope is that the terms added to the inner query will make it more
+** efficient.
+**
+** NAME AMBIGUITY
+**
+** This optimization is called the "WHERE-clause push-down optimization"
+** or sometimes the "predicate push-down optimization".
+**
+** Do not confuse this optimization with another unrelated optimization
+** with a similar name:  The "MySQL push-down optimization" causes WHERE
+** clause terms that can be evaluated using only the index and without
+** reference to the table are run first, so that if they are false,
+** unnecessary table seeks are avoided.
+**
+** RULES
+**
+** Do not attempt this optimization if:
+**
+**   (1) (** This restriction was removed on 2017-09-29.  We used to
+**           disallow this optimization for aggregate subqueries, but now
+**           it is allowed by putting the extra terms on the HAVING clause.
+**           The added HAVING clause is pointless if the subquery lacks
+**           a GROUP BY clause.  But such a HAVING clause is also harmless
+**           so there does not appear to be any reason to add extra logic
+**           to suppress it. **)
+**
+**   (2) The inner query is the recursive part of a common table expression.
+**
+**   (3) The inner query has a LIMIT clause (since the changes to the WHERE
+**       clause would change the meaning of the LIMIT).
+**
+**   (4) The inner query is the right operand of a LEFT JOIN and the
+**       expression to be pushed down does not come from the ON clause
+**       on that LEFT JOIN.
+**
+**   (5) The WHERE clause expression originates in the ON or USING clause
+**       of a LEFT JOIN where iCursor is not the right-hand table of that
+**       left join.  An example:
+**
+**           SELECT *
+**           FROM (SELECT 1 AS a1 UNION ALL SELECT 2) AS aa
+**           JOIN (SELECT 1 AS b2 UNION ALL SELECT 2) AS bb ON (a1=b2)
+**           LEFT JOIN (SELECT 8 AS c3 UNION ALL SELECT 9) AS cc ON (b2=2);
+**
+**       The correct answer is three rows:  (1,1,NULL),(2,2,8),(2,2,9).
+**       But if the (b2=2) term were to be pushed down into the bb subquery,
+**       then the (1,1,NULL) row would be suppressed.
+**
+**   (6) Window functions make things tricky as changes to the WHERE clause
+**       of the inner query could change the window over which window
+**       functions are calculated. Therefore, do not attempt the optimization
+**       if:
+**
+**     (6a) The inner query uses multiple incompatible window partitions.
+**
+**     (6b) The inner query is a compound and uses window-functions.
+**
+**     (6c) The WHERE clause does not consist entirely of constants and
+**          copies of expressions found in the PARTITION BY clause of
+**          all window-functions used by the sub-query. It is safe to
+**          filter out entire partitions, as this does not change the
+**          window over which any window-function is calculated.
+**
+**   (7) The inner query is a Common Table Expression (CTE) that should
+**       be materialized.  (This restriction is implemented in the calling
+**       routine.)
+**
+**   (8) If the subquery is a compound that uses UNION, INTERSECT,
+**       or EXCEPT, then all of the result set columns for all arms of
+**       the compound must use the BINARY collating sequence.
+**
+**   (9) All three of the following are true:
+**
+**       (9a) The WHERE clause expression originates in the ON or USING clause
+**            of a join (either an INNER or an OUTER join), and
+**
+**       (9b) The subquery is to the right of the ON/USING clause
+**
+**       (9c) There is a RIGHT JOIN (or FULL JOIN) in between the ON/USING
+**            clause and the subquery.
+**
+**       Without this restriction, the WHERE-clause push-down optimization
+**       might move the ON/USING filter expression from the left side of a
+**       RIGHT JOIN over to the right side, which leads to incorrect answers.
+**       See also restriction (6) in sqlite3ExprIsSingleTableConstraint().
+**
+**  (10) The inner query is not the right-hand table of a RIGHT JOIN.
+**
+**  (11) The subquery is not a VALUES clause
+**
+**  (12) The WHERE clause is not "rowid ISNULL" or the equivalent.  This
+**       case only comes up if SQLite is compiled using
+**       SQLITE_ALLOW_ROWID_IN_VIEW.
+**
+** Return 0 if no changes are made and non-zero if one or more WHERE clause
+** terms are duplicated into the subquery.
+*/
+static int pushDownWhereTerms(
+  Parse *pParse,        /* Parse context (for malloc() and error reporting) */
+  Select *pSubq,        /* The subquery whose WHERE clause is to be augmented */
+  Expr *pWhere,         /* The WHERE clause of the outer query */
+  SrcList *pSrcList,    /* The complete from clause of the outer query */
+  int iSrc              /* Which FROM clause term to try to push into  */
+){
+  Expr *pNew;
+  SrcItem *pSrc;        /* The subquery FROM term into which WHERE is pushed */
+  int nChng = 0;
+  pSrc = &pSrcList->a[iSrc];
+  if( pWhere==0 ) return 0;
+  if( pSubq->selFlags & (SF_Recursive|SF_MultiPart) ){
+    return 0;           /* restrictions (2) and (11) */
+  }
+  if( pSrc->fg.jointype & (JT_LTORJ|JT_RIGHT) ){
+    return 0;           /* restrictions (10) */
+  }
+
+  if( pSubq->pPrior ){
+    Select *pSel;
+    int notUnionAll = 0;
+    for(pSel=pSubq; pSel; pSel=pSel->pPrior){
+      u8 op = pSel->op;
+      assert( op==TK_ALL || op==TK_SELECT
+           || op==TK_UNION || op==TK_INTERSECT || op==TK_EXCEPT );
+      if( op!=TK_ALL && op!=TK_SELECT ){
+        notUnionAll = 1;
+      }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( pSel->pWin ) return 0;    /* restriction (6b) */
+#endif
+    }
+    if( notUnionAll ){
+      /* If any of the compound arms are connected using UNION, INTERSECT,
+      ** or EXCEPT, then we must ensure that none of the columns use a
+      ** non-BINARY collating sequence. */
+      for(pSel=pSubq; pSel; pSel=pSel->pPrior){
+        int ii;
+        const ExprList *pList = pSel->pEList;
+        assert( pList!=0 );
+        for(ii=0; ii<pList->nExpr; ii++){
+          CollSeq *pColl = sqlite3ExprCollSeq(pParse, pList->a[ii].pExpr);
+          if( !sqlite3IsBinary(pColl) ){
+            return 0;  /* Restriction (8) */
+          }
+        }
+      }
+    }
+  }else{
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( pSubq->pWin && pSubq->pWin->pPartition==0 ) return 0;
+#endif
+  }
+
+#ifdef SQLITE_DEBUG
+  /* Only the first term of a compound can have a WITH clause.  But make
+  ** sure no other terms are marked SF_Recursive in case something changes
+  ** in the future.
+  */
+  {
+    Select *pX;
+    for(pX=pSubq; pX; pX=pX->pPrior){
+      assert( (pX->selFlags & (SF_Recursive))==0 );
+    }
+  }
+#endif
+
+  if( pSubq->pLimit!=0 ){
+    return 0; /* restriction (3) */
+  }
+  while( pWhere->op==TK_AND ){
+    nChng += pushDownWhereTerms(pParse, pSubq, pWhere->pRight, pSrcList, iSrc);
+    pWhere = pWhere->pLeft;
+  }
+
+#if 0 /* These checks now done by sqlite3ExprIsSingleTableConstraint() */
+  if( ExprHasProperty(pWhere, EP_OuterON|EP_InnerON) /* (9a) */
+   && (pSrcList->a[0].fg.jointype & JT_LTORJ)!=0     /* Fast pre-test of (9c) */
+  ){
+    int jj;
+    for(jj=0; jj<iSrc; jj++){
+      if( pWhere->w.iJoin==pSrcList->a[jj].iCursor ){
+        /* If we reach this point, both (9a) and (9b) are satisfied.
+        ** The following loop checks (9c):
+        */
+        for(jj++; jj<iSrc; jj++){
+          if( (pSrcList->a[jj].fg.jointype & JT_RIGHT)!=0 ){
+            return 0;  /* restriction (9) */
+          }
+        }
+      }
+    }
+  }
+  if( isLeftJoin
+   && (ExprHasProperty(pWhere,EP_OuterON)==0
+         || pWhere->w.iJoin!=iCursor)
+  ){
+    return 0; /* restriction (4) */
+  }
+  if( ExprHasProperty(pWhere,EP_OuterON)
+   && pWhere->w.iJoin!=iCursor
+  ){
+    return 0; /* restriction (5) */
+  }
+#endif
+
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  if( ViewCanHaveRowid && (pWhere->op==TK_ISNULL || pWhere->op==TK_NOTNULL) ){
+    Expr *pLeft = pWhere->pLeft;
+    if( ALWAYS(pLeft)
+     && pLeft->op==TK_COLUMN
+     && pLeft->iColumn < 0
+    ){
+      return 0;  /* Restriction (12) */
+    }
+  }
+#endif
+
+  if( sqlite3ExprIsSingleTableConstraint(pWhere, pSrcList, iSrc, 1) ){
+    nChng++;
+    pSubq->selFlags |= SF_PushDown;
+    while( pSubq ){
+      SubstContext x;
+      pNew = sqlite3ExprDup(pParse->db, pWhere, 0);
+      unsetJoinExpr(pNew, -1, 1);
+      x.pParse = pParse;
+      x.iTable = pSrc->iCursor;
+      x.iNewTable = pSrc->iCursor;
+      x.isOuterJoin = 0;
+      x.pEList = pSubq->pEList;
+      x.pCList = findLeftmostExprlist(pSubq);
+      pNew = substExpr(&x, pNew);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( pSubq->pWin && 0==pushDownWindowCheck(pParse, pSubq, pNew) ){
+        /* Restriction 6c has prevented push-down in this case */
+        sqlite3ExprDelete(pParse->db, pNew);
+        nChng--;
+        break;
+      }
+#endif
+      if( pSubq->selFlags & SF_Aggregate ){
+        pSubq->pHaving = sqlite3ExprAnd(pParse, pSubq->pHaving, pNew);
+      }else{
+        pSubq->pWhere = sqlite3ExprAnd(pParse, pSubq->pWhere, pNew);
+      }
+      pSubq = pSubq->pPrior;
+    }
+  }
+  return nChng;
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+/*
+** Check to see if a subquery contains result-set columns that are
+** never used.  If it does, change the value of those result-set columns
+** to NULL so that they do not cause unnecessary work to compute.
+**
+** Return the number of column that were changed to NULL.
+*/
+static int disableUnusedSubqueryResultColumns(SrcItem *pItem){
+  int nCol;
+  Select *pSub;      /* The subquery to be simplified */
+  Select *pX;        /* For looping over compound elements of pSub */
+  Table *pTab;       /* The table that describes the subquery */
+  int j;             /* Column number */
+  int nChng = 0;     /* Number of columns converted to NULL */
+  Bitmask colUsed;   /* Columns that may not be NULLed out */
+
+  assert( pItem!=0 );
+  if( pItem->fg.isCorrelated || pItem->fg.isCte ){
+    return 0;
+  }
+  assert( pItem->pSTab!=0 );
+  pTab = pItem->pSTab;
+  assert( pItem->fg.isSubquery );
+  pSub = pItem->u4.pSubq->pSelect;
+  assert( pSub->pEList->nExpr==pTab->nCol );
+  for(pX=pSub; pX; pX=pX->pPrior){
+    if( (pX->selFlags & (SF_Distinct|SF_Aggregate))!=0 ){
+      testcase( pX->selFlags & SF_Distinct );
+      testcase( pX->selFlags & SF_Aggregate );
+      return 0;
+    }
+    if( pX->pPrior && pX->op!=TK_ALL ){
+      /* This optimization does not work for compound subqueries that
+      ** use UNION, INTERSECT, or EXCEPT.  Only UNION ALL is allowed. */
+      return 0;
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( pX->pWin ){
+      /* This optimization does not work for subqueries that use window
+      ** functions. */
+      return 0;
+    }
+#endif
+  }
+  colUsed = pItem->colUsed;
+  if( pSub->pOrderBy ){
+    ExprList *pList = pSub->pOrderBy;
+    for(j=0; j<pList->nExpr; j++){
+      u16 iCol = pList->a[j].u.x.iOrderByCol;
+      if( iCol>0 ){
+        iCol--;
+        colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol);
+      }
+    }
+  }
+  nCol = pTab->nCol;
+  for(j=0; j<nCol; j++){
+    Bitmask m = j<BMS-1 ? MASKBIT(j) : TOPBIT;
+    if( (m & colUsed)!=0 ) continue;
+    for(pX=pSub; pX; pX=pX->pPrior) {
+      Expr *pY = pX->pEList->a[j].pExpr;
+      if( pY->op==TK_NULL ) continue;
+      pY->op = TK_NULL;
+      ExprClearProperty(pY, EP_Skip|EP_Unlikely);
+      pX->selFlags |= SF_PushDown;
+      nChng++;
+    }
+  }
+  return nChng;
+}
+
+
+/*
+** The pFunc is the only aggregate function in the query.  Check to see
+** if the query is a candidate for the min/max optimization.
+**
+** If the query is a candidate for the min/max optimization, then set
+** *ppMinMax to be an ORDER BY clause to be used for the optimization
+** and return either WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX depending on
+** whether pFunc is a min() or max() function.
+**
+** If the query is not a candidate for the min/max optimization, return
+** WHERE_ORDERBY_NORMAL (which must be zero).
+**
+** This routine must be called after aggregate functions have been
+** located but before their arguments have been subjected to aggregate
+** analysis.
+*/
+static u8 minMaxQuery(sqlite3 *db, Expr *pFunc, ExprList **ppMinMax){
+  int eRet = WHERE_ORDERBY_NORMAL;      /* Return value */
+  ExprList *pEList;                     /* Arguments to agg function */
+  const char *zFunc;                    /* Name of aggregate function pFunc */
+  ExprList *pOrderBy;
+  u8 sortFlags = 0;
+
+  assert( *ppMinMax==0 );
+  assert( pFunc->op==TK_AGG_FUNCTION );
+  assert( !IsWindowFunc(pFunc) );
+  assert( ExprUseXList(pFunc) );
+  pEList = pFunc->x.pList;
+  if( pEList==0
+   || pEList->nExpr!=1
+   || ExprHasProperty(pFunc, EP_WinFunc)
+   || OptimizationDisabled(db, SQLITE_MinMaxOpt)
+  ){
+    return eRet;
+  }
+  assert( !ExprHasProperty(pFunc, EP_IntValue) );
+  zFunc = pFunc->u.zToken;
+  if( sqlite3StrICmp(zFunc, "min")==0 ){
+    eRet = WHERE_ORDERBY_MIN;
+    if( sqlite3ExprCanBeNull(pEList->a[0].pExpr) ){
+      sortFlags = KEYINFO_ORDER_BIGNULL;
+    }
+  }else if( sqlite3StrICmp(zFunc, "max")==0 ){
+    eRet = WHERE_ORDERBY_MAX;
+    sortFlags = KEYINFO_ORDER_DESC;
+  }else{
+    return eRet;
+  }
+  *ppMinMax = pOrderBy = sqlite3ExprListDup(db, pEList, 0);
+  assert( pOrderBy!=0 || db->mallocFailed );
+  if( pOrderBy ) pOrderBy->a[0].fg.sortFlags = sortFlags;
+  return eRet;
+}
+
+/*
+** The select statement passed as the first argument is an aggregate query.
+** The second argument is the associated aggregate-info object. This
+** function tests if the SELECT is of the form:
+**
+**   SELECT count(*) FROM <tbl>
+**
+** where table is a database table, not a sub-select or view. If the query
+** does match this pattern, then a pointer to the Table object representing
+** <tbl> is returned. Otherwise, NULL is returned.
+**
+** This routine checks to see if it is safe to use the count optimization.
+** A correct answer is still obtained (though perhaps more slowly) if
+** this routine returns NULL when it could have returned a table pointer.
+** But returning the pointer when NULL should have been returned can
+** result in incorrect answers and/or crashes.  So, when in doubt, return NULL.
+*/
+static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
+  Table *pTab;
+  Expr *pExpr;
+
+  assert( !p->pGroupBy );
+
+  if( p->pWhere
+   || p->pEList->nExpr!=1
+   || p->pSrc->nSrc!=1
+   || p->pSrc->a[0].fg.isSubquery
+   || pAggInfo->nFunc!=1
+   || p->pHaving
+  ){
+    return 0;
+  }
+  pTab = p->pSrc->a[0].pSTab;
+  assert( pTab!=0 );
+  assert( !IsView(pTab) );
+  if( !IsOrdinaryTable(pTab) ) return 0;
+  pExpr = p->pEList->a[0].pExpr;
+  assert( pExpr!=0 );
+  if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
+  if( pExpr->pAggInfo!=pAggInfo ) return 0;
+  if( (pAggInfo->aFunc[0].pFunc->funcFlags&SQLITE_FUNC_COUNT)==0 ) return 0;
+  assert( pAggInfo->aFunc[0].pFExpr==pExpr );
+  testcase( ExprHasProperty(pExpr, EP_Distinct) );
+  testcase( ExprHasProperty(pExpr, EP_WinFunc) );
+  if( ExprHasProperty(pExpr, EP_Distinct|EP_WinFunc) ) return 0;
+
+  return pTab;
+}
+
+/*
+** If the source-list item passed as an argument was augmented with an
+** INDEXED BY clause, then try to locate the specified index. If there
+** was such a clause and the named index cannot be found, return
+** SQLITE_ERROR and leave an error in pParse. Otherwise, populate
+** pFrom->pIndex and return SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3IndexedByLookup(Parse *pParse, SrcItem *pFrom){
+  Table *pTab = pFrom->pSTab;
+  char *zIndexedBy = pFrom->u1.zIndexedBy;
+  Index *pIdx;
+  assert( pTab!=0 );
+  assert( pFrom->fg.isIndexedBy!=0 );
+
+  for(pIdx=pTab->pIndex;
+      pIdx && sqlite3StrICmp(pIdx->zName, zIndexedBy);
+      pIdx=pIdx->pNext
+  );
+  if( !pIdx ){
+    sqlite3ErrorMsg(pParse, "no such index: %s", zIndexedBy, 0);
+    pParse->checkSchema = 1;
+    return SQLITE_ERROR;
+  }
+  assert( pFrom->fg.isCte==0 );
+  pFrom->u2.pIBIndex = pIdx;
+  return SQLITE_OK;
+}
+
+/*
+** Detect compound SELECT statements that use an ORDER BY clause with
+** an alternative collating sequence.
+**
+**    SELECT ... FROM t1 EXCEPT SELECT ... FROM t2 ORDER BY .. COLLATE ...
+**
+** These are rewritten as a subquery:
+**
+**    SELECT * FROM (SELECT ... FROM t1 EXCEPT SELECT ... FROM t2)
+**     ORDER BY ... COLLATE ...
+**
+** This transformation is necessary because the multiSelectOrderBy() routine
+** above that generates the code for a compound SELECT with an ORDER BY clause
+** uses a merge algorithm that requires the same collating sequence on the
+** result columns as on the ORDER BY clause.  See ticket
+** http://www.sqlite.org/src/info/6709574d2a
+**
+** This transformation is only needed for EXCEPT, INTERSECT, and UNION.
+** The UNION ALL operator works fine with multiSelectOrderBy() even when
+** there are COLLATE terms in the ORDER BY.
+*/
+static int convertCompoundSelectToSubquery(Walker *pWalker, Select *p){
+  int i;
+  Select *pNew;
+  Select *pX;
+  sqlite3 *db;
+  struct ExprList_item *a;
+  SrcList *pNewSrc;
+  Parse *pParse;
+  Token dummy;
+
+  if( p->pPrior==0 ) return WRC_Continue;
+  if( p->pOrderBy==0 ) return WRC_Continue;
+  for(pX=p; pX && (pX->op==TK_ALL || pX->op==TK_SELECT); pX=pX->pPrior){}
+  if( pX==0 ) return WRC_Continue;
+  a = p->pOrderBy->a;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  /* If iOrderByCol is already non-zero, then it has already been matched
+  ** to a result column of the SELECT statement. This occurs when the
+  ** SELECT is rewritten for window-functions processing and then passed
+  ** to sqlite3SelectPrep() and similar a second time. The rewriting done
+  ** by this function is not required in this case. */
+  if( a[0].u.x.iOrderByCol ) return WRC_Continue;
+#endif
+  for(i=p->pOrderBy->nExpr-1; i>=0; i--){
+    if( a[i].pExpr->flags & EP_Collate ) break;
+  }
+  if( i<0 ) return WRC_Continue;
+
+  /* If we reach this point, that means the transformation is required. */
+
+  pParse = pWalker->pParse;
+  db = pParse->db;
+  pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
+  if( pNew==0 ) return WRC_Abort;
+  memset(&dummy, 0, sizeof(dummy));
+  pNewSrc = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&dummy,pNew,0);
+  assert( pNewSrc!=0 || pParse->nErr );
+  if( pParse->nErr ){
+    sqlite3SrcListDelete(db, pNewSrc);
+    return WRC_Abort;
+  }
+  *pNew = *p;
+  p->pSrc = pNewSrc;
+  p->pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ASTERISK, 0));
+  p->op = TK_SELECT;
+  p->pWhere = 0;
+  pNew->pGroupBy = 0;
+  pNew->pHaving = 0;
+  pNew->pOrderBy = 0;
+  p->pPrior = 0;
+  p->pNext = 0;
+  p->pWith = 0;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  p->pWinDefn = 0;
+#endif
+  p->selFlags &= ~SF_Compound;
+  assert( (p->selFlags & SF_Converted)==0 );
+  p->selFlags |= SF_Converted;
+  assert( pNew->pPrior!=0 );
+  pNew->pPrior->pNext = pNew;
+  pNew->pLimit = 0;
+  return WRC_Continue;
+}
+
+/*
+** Check to see if the FROM clause term pFrom has table-valued function
+** arguments.  If it does, leave an error message in pParse and return
+** non-zero, since pFrom is not allowed to be a table-valued function.
+*/
+static int cannotBeFunction(Parse *pParse, SrcItem *pFrom){
+  if( pFrom->fg.isTabFunc ){
+    sqlite3ErrorMsg(pParse, "'%s' is not a function", pFrom->zName);
+    return 1;
+  }
+  return 0;
+}
+
+#ifndef SQLITE_OMIT_CTE
+/*
+** Argument pWith (which may be NULL) points to a linked list of nested
+** WITH contexts, from inner to outermost. If the table identified by
+** FROM clause element pItem is really a common-table-expression (CTE)
+** then return a pointer to the CTE definition for that table. Otherwise
+** return NULL.
+**
+** If a non-NULL value is returned, set *ppContext to point to the With
+** object that the returned CTE belongs to.
+*/
+static struct Cte *searchWith(
+  With *pWith,                    /* Current innermost WITH clause */
+  SrcItem *pItem,                 /* FROM clause element to resolve */
+  With **ppContext                /* OUT: WITH clause return value belongs to */
+){
+  const char *zName = pItem->zName;
+  With *p;
+  assert( pItem->fg.fixedSchema || pItem->u4.zDatabase==0 );
+  assert( zName!=0 );
+  for(p=pWith; p; p=p->pOuter){
+    int i;
+    for(i=0; i<p->nCte; i++){
+      if( sqlite3StrICmp(zName, p->a[i].zName)==0 ){
+        *ppContext = p;
+        return &p->a[i];
+      }
+    }
+    if( p->bView ) break;
+  }
+  return 0;
+}
+
+/* The code generator maintains a stack of active WITH clauses
+** with the inner-most WITH clause being at the top of the stack.
+**
+** This routine pushes the WITH clause passed as the second argument
+** onto the top of the stack. If argument bFree is true, then this
+** WITH clause will never be popped from the stack but should instead
+** be freed along with the Parse object. In other cases, when
+** bFree==0, the With object will be freed along with the SELECT
+** statement with which it is associated.
+**
+** This routine returns a copy of pWith.  Or, if bFree is true and
+** the pWith object is destroyed immediately due to an OOM condition,
+** then this routine return NULL.
+**
+** If bFree is true, do not continue to use the pWith pointer after
+** calling this routine,  Instead, use only the return value.
+*/
+SQLITE_PRIVATE With *sqlite3WithPush(Parse *pParse, With *pWith, u8 bFree){
+  if( pWith ){
+    if( bFree ){
+      pWith = (With*)sqlite3ParserAddCleanup(pParse, sqlite3WithDeleteGeneric,
+                      pWith);
+      if( pWith==0 ) return 0;
+    }
+    if( pParse->nErr==0 ){
+      assert( pParse->pWith!=pWith );
+      pWith->pOuter = pParse->pWith;
+      pParse->pWith = pWith;
+    }
+  }
+  return pWith;
+}
+
+/*
+** This function checks if argument pFrom refers to a CTE declared by
+** a WITH clause on the stack currently maintained by the parser (on the
+** pParse->pWith linked list).  And if currently processing a CTE
+** CTE expression, through routine checks to see if the reference is
+** a recursive reference to the CTE.
+**
+** If pFrom matches a CTE according to either of these two above, pFrom->pTab
+** and other fields are populated accordingly.
+**
+** Return 0 if no match is found.
+** Return 1 if a match is found.
+** Return 2 if an error condition is detected.
+*/
+static int resolveFromTermToCte(
+  Parse *pParse,                  /* The parsing context */
+  Walker *pWalker,                /* Current tree walker */
+  SrcItem *pFrom                  /* The FROM clause term to check */
+){
+  Cte *pCte;               /* Matched CTE (or NULL if no match) */
+  With *pWith;             /* The matching WITH */
+
+  assert( pFrom->pSTab==0 );
+  if( pParse->pWith==0 ){
+    /* There are no WITH clauses in the stack.  No match is possible */
+    return 0;
+  }
+  if( pParse->nErr ){
+    /* Prior errors might have left pParse->pWith in a goofy state, so
+    ** go no further. */
+    return 0;
+  }
+  assert( pFrom->fg.hadSchema==0 || pFrom->fg.notCte!=0 );
+  if( pFrom->fg.fixedSchema==0 && pFrom->u4.zDatabase!=0 ){
+    /* The FROM term contains a schema qualifier (ex: main.t1) and so
+    ** it cannot possibly be a CTE reference. */
+    return 0;
+  }
+  if( pFrom->fg.notCte ){
+    /* The FROM term is specifically excluded from matching a CTE.
+    **   (1)  It is part of a trigger that used to have zDatabase but had
+    **        zDatabase removed by sqlite3FixTriggerStep().
+    **   (2)  This is the first term in the FROM clause of an UPDATE.
+    */
+    return 0;
+  }
+  pCte = searchWith(pParse->pWith, pFrom, &pWith);
+  if( pCte ){
+    sqlite3 *db = pParse->db;
+    Table *pTab;
+    ExprList *pEList;
+    Select *pSel;
+    Select *pLeft;                /* Left-most SELECT statement */
+    Select *pRecTerm;             /* Left-most recursive term */
+    int bMayRecursive;            /* True if compound joined by UNION [ALL] */
+    With *pSavedWith;             /* Initial value of pParse->pWith */
+    int iRecTab = -1;             /* Cursor for recursive table */
+    CteUse *pCteUse;
+
+    /* If pCte->zCteErr is non-NULL at this point, then this is an illegal
+    ** recursive reference to CTE pCte. Leave an error in pParse and return
+    ** early. If pCte->zCteErr is NULL, then this is not a recursive reference.
+    ** In this case, proceed.  */
+    if( pCte->zCteErr ){
+      sqlite3ErrorMsg(pParse, pCte->zCteErr, pCte->zName);
+      return 2;
+    }
+    if( cannotBeFunction(pParse, pFrom) ) return 2;
+
+    assert( pFrom->pSTab==0 );
+    pTab = sqlite3DbMallocZero(db, sizeof(Table));
+    if( pTab==0 ) return 2;
+    pCteUse = pCte->pUse;
+    if( pCteUse==0 ){
+      pCte->pUse = pCteUse = sqlite3DbMallocZero(db, sizeof(pCteUse[0]));
+      if( pCteUse==0
+       || sqlite3ParserAddCleanup(pParse,sqlite3DbFree,pCteUse)==0
+      ){
+        sqlite3DbFree(db, pTab);
+        return 2;
+      }
+      pCteUse->eM10d = pCte->eM10d;
+    }
+    pFrom->pSTab = pTab;
+    pTab->nTabRef = 1;
+    pTab->zName = sqlite3DbStrDup(db, pCte->zName);
+    pTab->iPKey = -1;
+    pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
+    pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid;
+    sqlite3SrcItemAttachSubquery(pParse, pFrom, pCte->pSelect, 1);
+    if( db->mallocFailed ) return 2;
+    assert( pFrom->fg.isSubquery && pFrom->u4.pSubq );
+    pSel = pFrom->u4.pSubq->pSelect;
+    assert( pSel!=0 );
+    pSel->selFlags |= SF_CopyCte;
+    if( pFrom->fg.isIndexedBy ){
+      sqlite3ErrorMsg(pParse, "no such index: \"%s\"", pFrom->u1.zIndexedBy);
+      return 2;
+    }
+    assert( !pFrom->fg.isIndexedBy );
+    pFrom->fg.isCte = 1;
+    pFrom->u2.pCteUse = pCteUse;
+    pCteUse->nUse++;
+
+    /* Check if this is a recursive CTE. */
+    pRecTerm = pSel;
+    bMayRecursive = ( pSel->op==TK_ALL || pSel->op==TK_UNION );
+    while( bMayRecursive && pRecTerm->op==pSel->op ){
+      int i;
+      SrcList *pSrc = pRecTerm->pSrc;
+      assert( pRecTerm->pPrior!=0 );
+      for(i=0; i<pSrc->nSrc; i++){
+        SrcItem *pItem = &pSrc->a[i];
+        if( pItem->zName!=0
+         && !pItem->fg.hadSchema
+         && ALWAYS( !pItem->fg.isSubquery )
+         && (pItem->fg.fixedSchema || pItem->u4.zDatabase==0)
+         && 0==sqlite3StrICmp(pItem->zName, pCte->zName)
+        ){
+          pItem->pSTab = pTab;
+          pTab->nTabRef++;
+          pItem->fg.isRecursive = 1;
+          if( pRecTerm->selFlags & SF_Recursive ){
+            sqlite3ErrorMsg(pParse,
+               "multiple references to recursive table: %s", pCte->zName
+            );
+            return 2;
+          }
+          pRecTerm->selFlags |= SF_Recursive;
+          if( iRecTab<0 ) iRecTab = pParse->nTab++;
+          pItem->iCursor = iRecTab;
+        }
+      }
+      if( (pRecTerm->selFlags & SF_Recursive)==0 ) break;
+      pRecTerm = pRecTerm->pPrior;
+    }
+
+    pCte->zCteErr = "circular reference: %s";
+    pSavedWith = pParse->pWith;
+    pParse->pWith = pWith;
+    if( pSel->selFlags & SF_Recursive ){
+      int rc;
+      assert( pRecTerm!=0 );
+      assert( (pRecTerm->selFlags & SF_Recursive)==0 );
+      assert( pRecTerm->pNext!=0 );
+      assert( (pRecTerm->pNext->selFlags & SF_Recursive)!=0 );
+      assert( pRecTerm->pWith==0 );
+      pRecTerm->pWith = pSel->pWith;
+      rc = sqlite3WalkSelect(pWalker, pRecTerm);
+      pRecTerm->pWith = 0;
+      if( rc ){
+        pParse->pWith = pSavedWith;
+        return 2;
+      }
+    }else{
+      if( sqlite3WalkSelect(pWalker, pSel) ){
+        pParse->pWith = pSavedWith;
+        return 2;
+      }
+    }
+    pParse->pWith = pWith;
+
+    for(pLeft=pSel; pLeft->pPrior; pLeft=pLeft->pPrior);
+    pEList = pLeft->pEList;
+    if( pCte->pCols ){
+      if( pEList && pEList->nExpr!=pCte->pCols->nExpr ){
+        sqlite3ErrorMsg(pParse, "table %s has %d values for %d columns",
+            pCte->zName, pEList->nExpr, pCte->pCols->nExpr
+        );
+        pParse->pWith = pSavedWith;
+        return 2;
+      }
+      pEList = pCte->pCols;
+    }
+
+    sqlite3ColumnsFromExprList(pParse, pEList, &pTab->nCol, &pTab->aCol);
+    if( bMayRecursive ){
+      if( pSel->selFlags & SF_Recursive ){
+        pCte->zCteErr = "multiple recursive references: %s";
+      }else{
+        pCte->zCteErr = "recursive reference in a subquery: %s";
+      }
+      sqlite3WalkSelect(pWalker, pSel);
+    }
+    pCte->zCteErr = 0;
+    pParse->pWith = pSavedWith;
+    return 1;  /* Success */
+  }
+  return 0;  /* No match */
+}
+#endif
+
+#ifndef SQLITE_OMIT_CTE
+/*
+** If the SELECT passed as the second argument has an associated WITH
+** clause, pop it from the stack stored as part of the Parse object.
+**
+** This function is used as the xSelectCallback2() callback by
+** sqlite3SelectExpand() when walking a SELECT tree to resolve table
+** names and other FROM clause elements.
+*/
+SQLITE_PRIVATE void sqlite3SelectPopWith(Walker *pWalker, Select *p){
+  Parse *pParse = pWalker->pParse;
+  if( OK_IF_ALWAYS_TRUE(pParse->pWith) && p->pPrior==0 ){
+    With *pWith = findRightmost(p)->pWith;
+    if( pWith!=0 ){
+      assert( pParse->pWith==pWith || pParse->nErr );
+      pParse->pWith = pWith->pOuter;
+    }
+  }
+}
+#endif
+
+/*
+** The SrcItem structure passed as the second argument represents a
+** sub-query in the FROM clause of a SELECT statement. This function
+** allocates and populates the SrcItem.pTab object. If successful,
+** SQLITE_OK is returned. Otherwise, if an OOM error is encountered,
+** SQLITE_NOMEM.
+*/
+SQLITE_PRIVATE int sqlite3ExpandSubquery(Parse *pParse, SrcItem *pFrom){
+  Select *pSel;
+  Table *pTab;
+
+  assert( pFrom->fg.isSubquery );
+  assert( pFrom->u4.pSubq!=0 );
+  pSel = pFrom->u4.pSubq->pSelect;
+  assert( pSel );
+  pFrom->pSTab = pTab = sqlite3DbMallocZero(pParse->db, sizeof(Table));
+  if( pTab==0 ) return SQLITE_NOMEM;
+  pTab->nTabRef = 1;
+  if( pFrom->zAlias ){
+    pTab->zName = sqlite3DbStrDup(pParse->db, pFrom->zAlias);
+  }else{
+    pTab->zName = sqlite3MPrintf(pParse->db, "%!S", pFrom);
+  }
+  while( pSel->pPrior ){ pSel = pSel->pPrior; }
+  sqlite3ColumnsFromExprList(pParse, pSel->pEList,&pTab->nCol,&pTab->aCol);
+  pTab->iPKey = -1;
+  pTab->eTabType = TABTYP_VIEW;
+  pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
+#ifndef SQLITE_ALLOW_ROWID_IN_VIEW
+  /* The usual case - do not allow ROWID on a subquery */
+  pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid;
+#else
+  /* Legacy compatibility mode */
+  pTab->tabFlags |= TF_Ephemeral | sqlite3Config.mNoVisibleRowid;
+#endif
+  return pParse->nErr ? SQLITE_ERROR : SQLITE_OK;
+}
+
+
+/*
+** Check the N SrcItem objects to the right of pBase.  (N might be zero!)
+** If any of those SrcItem objects have a USING clause containing zName
+** then return true.
+**
+** If N is zero, or none of the N SrcItem objects to the right of pBase
+** contains a USING clause, or if none of the USING clauses contain zName,
+** then return false.
+*/
+static int inAnyUsingClause(
+  const char *zName, /* Name we are looking for */
+  SrcItem *pBase,    /* The base SrcItem.  Looking at pBase[1] and following */
+  int N              /* How many SrcItems to check */
+){
+  while( N>0 ){
+    N--;
+    pBase++;
+    if( pBase->fg.isUsing==0 ) continue;
+    if( NEVER(pBase->u3.pUsing==0) ) continue;
+    if( sqlite3IdListIndex(pBase->u3.pUsing, zName)>=0 ) return 1;
+  }
+  return 0;
+}
+
+
+/*
+** This routine is a Walker callback for "expanding" a SELECT statement.
+** "Expanding" means to do the following:
+**
+**    (1)  Make sure VDBE cursor numbers have been assigned to every
+**         element of the FROM clause.
+**
+**    (2)  Fill in the pTabList->a[].pTab fields in the SrcList that
+**         defines FROM clause.  When views appear in the FROM clause,
+**         fill pTabList->a[].pSelect with a copy of the SELECT statement
+**         that implements the view.  A copy is made of the view's SELECT
+**         statement so that we can freely modify or delete that statement
+**         without worrying about messing up the persistent representation
+**         of the view.
+**
+**    (3)  Add terms to the WHERE clause to accommodate the NATURAL keyword
+**         on joins and the ON and USING clause of joins.
+**
+**    (4)  Scan the list of columns in the result set (pEList) looking
+**         for instances of the "*" operator or the TABLE.* operator.
+**         If found, expand each "*" to be every column in every table
+**         and TABLE.* to be every column in TABLE.
+**
+*/
+static int selectExpander(Walker *pWalker, Select *p){
+  Parse *pParse = pWalker->pParse;
+  int i, j, k, rc;
+  SrcList *pTabList;
+  ExprList *pEList;
+  SrcItem *pFrom;
+  sqlite3 *db = pParse->db;
+  Expr *pE, *pRight, *pExpr;
+  u16 selFlags = p->selFlags;
+  u32 elistFlags = 0;
+
+  p->selFlags |= SF_Expanded;
+  if( db->mallocFailed  ){
+    return WRC_Abort;
+  }
+  assert( p->pSrc!=0 );
+  if( (selFlags & SF_Expanded)!=0 ){
+    return WRC_Prune;
+  }
+  if( pWalker->eCode ){
+    /* Renumber selId because it has been copied from a view */
+    p->selId = ++pParse->nSelect;
+  }
+  pTabList = p->pSrc;
+  pEList = p->pEList;
+  if( pParse->pWith && (p->selFlags & SF_View) ){
+    if( p->pWith==0 ){
+      p->pWith = (With*)sqlite3DbMallocZero(db, sizeof(With));
+      if( p->pWith==0 ){
+        return WRC_Abort;
+      }
+    }
+    p->pWith->bView = 1;
+  }
+  sqlite3WithPush(pParse, p->pWith, 0);
+
+  /* Make sure cursor numbers have been assigned to all entries in
+  ** the FROM clause of the SELECT statement.
+  */
+  sqlite3SrcListAssignCursors(pParse, pTabList);
+
+  /* Look up every table named in the FROM clause of the select.  If
+  ** an entry of the FROM clause is a subquery instead of a table or view,
+  ** then create a transient table structure to describe the subquery.
+  */
+  for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+    Table *pTab;
+    assert( pFrom->fg.isRecursive==0 || pFrom->pSTab!=0 );
+    if( pFrom->pSTab ) continue;
+    assert( pFrom->fg.isRecursive==0 );
+    if( pFrom->zName==0 ){
+#ifndef SQLITE_OMIT_SUBQUERY
+      Select *pSel;
+      assert( pFrom->fg.isSubquery && pFrom->u4.pSubq!=0 );
+      pSel = pFrom->u4.pSubq->pSelect;
+      /* A sub-query in the FROM clause of a SELECT */
+      assert( pSel!=0 );
+      assert( pFrom->pSTab==0 );
+      if( sqlite3WalkSelect(pWalker, pSel) ) return WRC_Abort;
+      if( sqlite3ExpandSubquery(pParse, pFrom) ) return WRC_Abort;
+#endif
+#ifndef SQLITE_OMIT_CTE
+    }else if( (rc = resolveFromTermToCte(pParse, pWalker, pFrom))!=0 ){
+      if( rc>1 ) return WRC_Abort;
+      pTab = pFrom->pSTab;
+      assert( pTab!=0 );
+#endif
+    }else{
+      /* An ordinary table or view name in the FROM clause */
+      assert( pFrom->pSTab==0 );
+      pFrom->pSTab = pTab = sqlite3LocateTableItem(pParse, 0, pFrom);
+      if( pTab==0 ) return WRC_Abort;
+      if( pTab->nTabRef>=0xffff ){
+        sqlite3ErrorMsg(pParse, "too many references to \"%s\": max 65535",
+           pTab->zName);
+        pFrom->pSTab = 0;
+        return WRC_Abort;
+      }
+      pTab->nTabRef++;
+      if( !IsVirtual(pTab) && cannotBeFunction(pParse, pFrom) ){
+        return WRC_Abort;
+      }
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+      if( !IsOrdinaryTable(pTab) ){
+        i16 nCol;
+        u8 eCodeOrig = pWalker->eCode;
+        if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
+        assert( pFrom->fg.isSubquery==0 );
+        if( IsView(pTab) ){
+          if( (db->flags & SQLITE_EnableView)==0
+           && pTab->pSchema!=db->aDb[1].pSchema
+          ){
+            sqlite3ErrorMsg(pParse, "access to view \"%s\" prohibited",
+              pTab->zName);
+          }
+          sqlite3SrcItemAttachSubquery(pParse, pFrom, pTab->u.view.pSelect, 1);
+        }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+        else if( ALWAYS(IsVirtual(pTab))
+         && pFrom->fg.fromDDL
+         && ALWAYS(pTab->u.vtab.p!=0)
+         && pTab->u.vtab.p->eVtabRisk > ((db->flags & SQLITE_TrustedSchema)!=0)
+        ){
+          sqlite3ErrorMsg(pParse, "unsafe use of virtual table \"%s\"",
+                                  pTab->zName);
+        }
+        assert( SQLITE_VTABRISK_Normal==1 && SQLITE_VTABRISK_High==2 );
+#endif
+        nCol = pTab->nCol;
+        pTab->nCol = -1;
+        pWalker->eCode = 1;  /* Turn on Select.selId renumbering */
+        if( pFrom->fg.isSubquery ){
+          sqlite3WalkSelect(pWalker, pFrom->u4.pSubq->pSelect);
+        }
+        pWalker->eCode = eCodeOrig;
+        pTab->nCol = nCol;
+      }
+#endif
+    }
+
+    /* Locate the index named by the INDEXED BY clause, if any. */
+    if( pFrom->fg.isIndexedBy && sqlite3IndexedByLookup(pParse, pFrom) ){
+      return WRC_Abort;
+    }
+  }
+
+  /* Process NATURAL keywords, and ON and USING clauses of joins.
+  */
+  assert( db->mallocFailed==0 || pParse->nErr!=0 );
+  if( pParse->nErr || sqlite3ProcessJoin(pParse, p) ){
+    return WRC_Abort;
+  }
+
+  /* For every "*" that occurs in the column list, insert the names of
+  ** all columns in all tables.  And for every TABLE.* insert the names
+  ** of all columns in TABLE.  The parser inserted a special expression
+  ** with the TK_ASTERISK operator for each "*" that it found in the column
+  ** list.  The following code just has to locate the TK_ASTERISK
+  ** expressions and expand each one to the list of all columns in
+  ** all tables.
+  **
+  ** The first loop just checks to see if there are any "*" operators
+  ** that need expanding.
+  */
+  for(k=0; k<pEList->nExpr; k++){
+    pE = pEList->a[k].pExpr;
+    if( pE->op==TK_ASTERISK ) break;
+    assert( pE->op!=TK_DOT || pE->pRight!=0 );
+    assert( pE->op!=TK_DOT || (pE->pLeft!=0 && pE->pLeft->op==TK_ID) );
+    if( pE->op==TK_DOT && pE->pRight->op==TK_ASTERISK ) break;
+    elistFlags |= pE->flags;
+  }
+  if( k<pEList->nExpr ){
+    /*
+    ** If we get here it means the result set contains one or more "*"
+    ** operators that need to be expanded.  Loop through each expression
+    ** in the result set and expand them one by one.
+    */
+    struct ExprList_item *a = pEList->a;
+    ExprList *pNew = 0;
+    int flags = pParse->db->flags;
+    int longNames = (flags & SQLITE_FullColNames)!=0
+                      && (flags & SQLITE_ShortColNames)==0;
+
+    for(k=0; k<pEList->nExpr; k++){
+      pE = a[k].pExpr;
+      elistFlags |= pE->flags;
+      pRight = pE->pRight;
+      assert( pE->op!=TK_DOT || pRight!=0 );
+      if( pE->op!=TK_ASTERISK
+       && (pE->op!=TK_DOT || pRight->op!=TK_ASTERISK)
+      ){
+        /* This particular expression does not need to be expanded.
+        */
+        pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr);
+        if( pNew ){
+          pNew->a[pNew->nExpr-1].zEName = a[k].zEName;
+          pNew->a[pNew->nExpr-1].fg.eEName = a[k].fg.eEName;
+          a[k].zEName = 0;
+        }
+        a[k].pExpr = 0;
+      }else{
+        /* This expression is a "*" or a "TABLE.*" and needs to be
+        ** expanded. */
+        int tableSeen = 0;      /* Set to 1 when TABLE matches */
+        char *zTName = 0;       /* text of name of TABLE */
+        int iErrOfst;
+        if( pE->op==TK_DOT ){
+          assert( (selFlags & SF_NestedFrom)==0 );
+          assert( pE->pLeft!=0 );
+          assert( !ExprHasProperty(pE->pLeft, EP_IntValue) );
+          zTName = pE->pLeft->u.zToken;
+          assert( ExprUseWOfst(pE->pLeft) );
+          iErrOfst = pE->pRight->w.iOfst;
+        }else{
+          assert( ExprUseWOfst(pE) );
+          iErrOfst = pE->w.iOfst;
+        }
+        for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+          int nAdd;                    /* Number of cols including rowid */
+          Table *pTab = pFrom->pSTab;  /* Table for this data source */
+          ExprList *pNestedFrom;       /* Result-set of a nested FROM clause */
+          char *zTabName;              /* AS name for this data source */
+          const char *zSchemaName = 0; /* Schema name for this data source */
+          int iDb;                     /* Schema index for this data src */
+          IdList *pUsing;              /* USING clause for pFrom[1] */
+
+          if( (zTabName = pFrom->zAlias)==0 ){
+            zTabName = pTab->zName;
+          }
+          if( db->mallocFailed ) break;
+          assert( (int)pFrom->fg.isNestedFrom == IsNestedFrom(pFrom) );
+          if( pFrom->fg.isNestedFrom ){
+            assert( pFrom->fg.isSubquery && pFrom->u4.pSubq );
+            assert( pFrom->u4.pSubq->pSelect!=0 );
+            pNestedFrom = pFrom->u4.pSubq->pSelect->pEList;
+            assert( pNestedFrom!=0 );
+            assert( pNestedFrom->nExpr==pTab->nCol );
+            assert( VisibleRowid(pTab)==0 || ViewCanHaveRowid );
+          }else{
+            if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){
+              continue;
+            }
+            pNestedFrom = 0;
+            iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+            zSchemaName = iDb>=0 ? db->aDb[iDb].zDbSName : "*";
+          }
+          if( i+1<pTabList->nSrc
+           && pFrom[1].fg.isUsing
+           && (selFlags & SF_NestedFrom)!=0
+          ){
+            int ii;
+            pUsing = pFrom[1].u3.pUsing;
+            for(ii=0; ii<pUsing->nId; ii++){
+              const char *zUName = pUsing->a[ii].zName;
+              pRight = sqlite3Expr(db, TK_ID, zUName);
+              sqlite3ExprSetErrorOffset(pRight, iErrOfst);
+              pNew = sqlite3ExprListAppend(pParse, pNew, pRight);
+              if( pNew ){
+                struct ExprList_item *pX = &pNew->a[pNew->nExpr-1];
+                assert( pX->zEName==0 );
+                pX->zEName = sqlite3MPrintf(db,"..%s", zUName);
+                pX->fg.eEName = ENAME_TAB;
+                pX->fg.bUsingTerm = 1;
+              }
+            }
+          }else{
+            pUsing = 0;
+          }
+
+          nAdd = pTab->nCol;
+          if( VisibleRowid(pTab) && (selFlags & SF_NestedFrom)!=0 ) nAdd++;
+          for(j=0; j<nAdd; j++){
+            const char *zName;
+            struct ExprList_item *pX; /* Newly added ExprList term */
+
+            if( j==pTab->nCol ){
+              zName = sqlite3RowidAlias(pTab);
+              if( zName==0 ) continue;
+            }else{
+              zName = pTab->aCol[j].zCnName;
+
+              /* If pTab is actually an SF_NestedFrom sub-select, do not
+              ** expand any ENAME_ROWID columns.  */
+              if( pNestedFrom && pNestedFrom->a[j].fg.eEName==ENAME_ROWID ){
+                continue;
+              }
+
+              if( zTName
+               && pNestedFrom
+               && sqlite3MatchEName(&pNestedFrom->a[j], 0, zTName, 0, 0)==0
+              ){
+                continue;
+              }
+
+              /* If a column is marked as 'hidden', omit it from the expanded
+              ** result-set list unless the SELECT has the SF_IncludeHidden
+              ** bit set.
+              */
+              if( (p->selFlags & SF_IncludeHidden)==0
+                && IsHiddenColumn(&pTab->aCol[j])
+              ){
+                continue;
+              }
+              if( (pTab->aCol[j].colFlags & COLFLAG_NOEXPAND)!=0
+               && zTName==0
+               && (selFlags & (SF_NestedFrom))==0
+              ){
+                continue;
+              }
+            }
+            assert( zName );
+            tableSeen = 1;
+
+            if( i>0 && zTName==0 && (selFlags & SF_NestedFrom)==0 ){
+              if( pFrom->fg.isUsing
+               && sqlite3IdListIndex(pFrom->u3.pUsing, zName)>=0
+              ){
+                /* In a join with a USING clause, omit columns in the
+                ** using clause from the table on the right. */
+                continue;
+              }
+            }
+            pRight = sqlite3Expr(db, TK_ID, zName);
+            if( (pTabList->nSrc>1
+                 && (  (pFrom->fg.jointype & JT_LTORJ)==0
+                     || (selFlags & SF_NestedFrom)!=0
+                     || !inAnyUsingClause(zName,pFrom,pTabList->nSrc-i-1)
+                    )
+                )
+             || IN_RENAME_OBJECT
+            ){
+              Expr *pLeft;
+              pLeft = sqlite3Expr(db, TK_ID, zTabName);
+              pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight);
+              if( IN_RENAME_OBJECT && pE->pLeft ){
+                sqlite3RenameTokenRemap(pParse, pLeft, pE->pLeft);
+              }
+              if( zSchemaName ){
+                pLeft = sqlite3Expr(db, TK_ID, zSchemaName);
+                pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pExpr);
+              }
+            }else{
+              pExpr = pRight;
+            }
+            sqlite3ExprSetErrorOffset(pExpr, iErrOfst);
+            pNew = sqlite3ExprListAppend(pParse, pNew, pExpr);
+            if( pNew==0 ){
+              break;  /* OOM */
+            }
+            pX = &pNew->a[pNew->nExpr-1];
+            assert( pX->zEName==0 );
+            if( (selFlags & SF_NestedFrom)!=0 && !IN_RENAME_OBJECT ){
+              if( pNestedFrom && (!ViewCanHaveRowid || j<pNestedFrom->nExpr) ){
+                assert( j<pNestedFrom->nExpr );
+                pX->zEName = sqlite3DbStrDup(db, pNestedFrom->a[j].zEName);
+                testcase( pX->zEName==0 );
+              }else{
+                pX->zEName = sqlite3MPrintf(db, "%s.%s.%s",
+                                           zSchemaName, zTabName, zName);
+                testcase( pX->zEName==0 );
+              }
+              pX->fg.eEName = (j==pTab->nCol ? ENAME_ROWID : ENAME_TAB);
+              if( (pFrom->fg.isUsing
+                   && sqlite3IdListIndex(pFrom->u3.pUsing, zName)>=0)
+               || (pUsing && sqlite3IdListIndex(pUsing, zName)>=0)
+               || (j<pTab->nCol && (pTab->aCol[j].colFlags & COLFLAG_NOEXPAND))
+              ){
+                pX->fg.bNoExpand = 1;
+              }
+            }else if( longNames ){
+              pX->zEName = sqlite3MPrintf(db, "%s.%s", zTabName, zName);
+              pX->fg.eEName = ENAME_NAME;
+            }else{
+              pX->zEName = sqlite3DbStrDup(db, zName);
+              pX->fg.eEName = ENAME_NAME;
+            }
+          }
+        }
+        if( !tableSeen ){
+          if( zTName ){
+            sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
+          }else{
+            sqlite3ErrorMsg(pParse, "no tables specified");
+          }
+        }
+      }
+    }
+    sqlite3ExprListDelete(db, pEList);
+    p->pEList = pNew;
+  }
+  if( p->pEList ){
+    if( p->pEList->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+      sqlite3ErrorMsg(pParse, "too many columns in result set");
+      return WRC_Abort;
+    }
+    if( (elistFlags & (EP_HasFunc|EP_Subquery))!=0 ){
+      p->selFlags |= SF_ComplexResult;
+    }
+  }
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x8 ){
+    TREETRACE(0x8,pParse,p,("After result-set wildcard expansion:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+  return WRC_Continue;
+}
+
+#if SQLITE_DEBUG
+/*
+** Always assert.  This xSelectCallback2 implementation proves that the
+** xSelectCallback2 is never invoked.
+*/
+SQLITE_PRIVATE void sqlite3SelectWalkAssert2(Walker *NotUsed, Select *NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  assert( 0 );
+}
+#endif
+/*
+** This routine "expands" a SELECT statement and all of its subqueries.
+** For additional information on what it means to "expand" a SELECT
+** statement, see the comment on the selectExpand worker callback above.
+**
+** Expanding a SELECT statement is the first step in processing a
+** SELECT statement.  The SELECT statement must be expanded before
+** name resolution is performed.
+**
+** If anything goes wrong, an error message is written into pParse.
+** The calling function can detect the problem by looking at pParse->nErr
+** and/or pParse->db->mallocFailed.
+*/
+static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){
+  Walker w;
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.pParse = pParse;
+  if( OK_IF_ALWAYS_TRUE(pParse->hasCompound) ){
+    w.xSelectCallback = convertCompoundSelectToSubquery;
+    w.xSelectCallback2 = 0;
+    sqlite3WalkSelect(&w, pSelect);
+  }
+  w.xSelectCallback = selectExpander;
+  w.xSelectCallback2 = sqlite3SelectPopWith;
+  w.eCode = 0;
+  sqlite3WalkSelect(&w, pSelect);
+}
+
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** This is a Walker.xSelectCallback callback for the sqlite3SelectTypeInfo()
+** interface.
+**
+** For each FROM-clause subquery, add Column.zType, Column.zColl, and
+** Column.affinity information to the Table structure that represents
+** the result set of that subquery.
+**
+** The Table structure that represents the result set was constructed
+** by selectExpander() but the type and collation and affinity information
+** was omitted at that point because identifiers had not yet been resolved.
+** This routine is called after identifier resolution.
+*/
+static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
+  Parse *pParse;
+  int i;
+  SrcList *pTabList;
+  SrcItem *pFrom;
+
+  if( p->selFlags & SF_HasTypeInfo ) return;
+  p->selFlags |= SF_HasTypeInfo;
+  pParse = pWalker->pParse;
+  assert( (p->selFlags & SF_Resolved) );
+  pTabList = p->pSrc;
+  for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+    Table *pTab = pFrom->pSTab;
+    assert( pTab!=0 );
+    if( (pTab->tabFlags & TF_Ephemeral)!=0 && pFrom->fg.isSubquery ){
+      /* A sub-query in the FROM clause of a SELECT */
+      Select *pSel = pFrom->u4.pSubq->pSelect;
+      sqlite3SubqueryColumnTypes(pParse, pTab, pSel, SQLITE_AFF_NONE);
+    }
+  }
+}
+#endif
+
+
+/*
+** This routine adds datatype and collating sequence information to
+** the Table structures of all FROM-clause subqueries in a
+** SELECT statement.
+**
+** Use this routine after name resolution.
+*/
+static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){
+#ifndef SQLITE_OMIT_SUBQUERY
+  Walker w;
+  w.xSelectCallback = sqlite3SelectWalkNoop;
+  w.xSelectCallback2 = selectAddSubqueryTypeInfo;
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.pParse = pParse;
+  sqlite3WalkSelect(&w, pSelect);
+#endif
+}
+
+
+/*
+** This routine sets up a SELECT statement for processing.  The
+** following is accomplished:
+**
+**     *  VDBE Cursor numbers are assigned to all FROM-clause terms.
+**     *  Ephemeral Table objects are created for all FROM-clause subqueries.
+**     *  ON and USING clauses are shifted into WHERE statements
+**     *  Wildcards "*" and "TABLE.*" in result sets are expanded.
+**     *  Identifiers in expression are matched to tables.
+**
+** This routine acts recursively on all subqueries within the SELECT.
+*/
+SQLITE_PRIVATE void sqlite3SelectPrep(
+  Parse *pParse,         /* The parser context */
+  Select *p,             /* The SELECT statement being coded. */
+  NameContext *pOuterNC  /* Name context for container */
+){
+  assert( p!=0 || pParse->db->mallocFailed );
+  assert( pParse->db->pParse==pParse );
+  if( pParse->db->mallocFailed ) return;
+  if( p->selFlags & SF_HasTypeInfo ) return;
+  sqlite3SelectExpand(pParse, p);
+  if( pParse->nErr ) return;
+  sqlite3ResolveSelectNames(pParse, p, pOuterNC);
+  if( pParse->nErr ) return;
+  sqlite3SelectAddTypeInfo(pParse, p);
+}
+
+#if TREETRACE_ENABLED
+/*
+** Display all information about an AggInfo object
+*/
+static void printAggInfo(AggInfo *pAggInfo){
+  int ii;
+  sqlite3DebugPrintf("AggInfo %d/%p:\n",
+     pAggInfo->selId, pAggInfo);
+  for(ii=0; ii<pAggInfo->nColumn; ii++){
+    struct AggInfo_col *pCol = &pAggInfo->aCol[ii];
+    sqlite3DebugPrintf(
+       "agg-column[%d] pTab=%s iTable=%d iColumn=%d iMem=%d"
+       " iSorterColumn=%d %s\n",
+       ii, pCol->pTab ? pCol->pTab->zName : "NULL",
+       pCol->iTable, pCol->iColumn, pAggInfo->iFirstReg+ii,
+       pCol->iSorterColumn,
+       ii>=pAggInfo->nAccumulator ? "" : " Accumulator");
+    sqlite3TreeViewExpr(0, pAggInfo->aCol[ii].pCExpr, 0);
+  }
+  for(ii=0; ii<pAggInfo->nFunc; ii++){
+    sqlite3DebugPrintf("agg-func[%d]: iMem=%d\n",
+        ii, pAggInfo->iFirstReg+pAggInfo->nColumn+ii);
+    sqlite3TreeViewExpr(0, pAggInfo->aFunc[ii].pFExpr, 0);
+  }
+}
+#endif /* TREETRACE_ENABLED */
+
+/*
+** Analyze the arguments to aggregate functions.  Create new pAggInfo->aCol[]
+** entries for columns that are arguments to aggregate functions but which
+** are not otherwise used.
+**
+** The aCol[] entries in AggInfo prior to nAccumulator are columns that
+** are referenced outside of aggregate functions.  These might be columns
+** that are part of the GROUP by clause, for example.  Other database engines
+** would throw an error if there is a column reference that is not in the
+** GROUP BY clause and that is not part of an aggregate function argument.
+** But SQLite allows this.
+**
+** The aCol[] entries beginning with the aCol[nAccumulator] and following
+** are column references that are used exclusively as arguments to
+** aggregate functions.  This routine is responsible for computing
+** (or recomputing) those aCol[] entries.
+*/
+static void analyzeAggFuncArgs(
+  AggInfo *pAggInfo,
+  NameContext *pNC
+){
+  int i;
+  assert( pAggInfo!=0 );
+  assert( pAggInfo->iFirstReg==0 );
+  pNC->ncFlags |= NC_InAggFunc;
+  for(i=0; i<pAggInfo->nFunc; i++){
+    Expr *pExpr = pAggInfo->aFunc[i].pFExpr;
+    assert( pExpr->op==TK_FUNCTION || pExpr->op==TK_AGG_FUNCTION );
+    assert( ExprUseXList(pExpr) );
+    sqlite3ExprAnalyzeAggList(pNC, pExpr->x.pList);
+    if( pExpr->pLeft ){
+      assert( pExpr->pLeft->op==TK_ORDER );
+      assert( ExprUseXList(pExpr->pLeft) );
+      sqlite3ExprAnalyzeAggList(pNC, pExpr->pLeft->x.pList);
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    assert( !IsWindowFunc(pExpr) );
+    if( ExprHasProperty(pExpr, EP_WinFunc) ){
+      sqlite3ExprAnalyzeAggregates(pNC, pExpr->y.pWin->pFilter);
+    }
+#endif
+  }
+  pNC->ncFlags &= ~NC_InAggFunc;
+}
+
+/*
+** An index on expressions is being used in the inner loop of an
+** aggregate query with a GROUP BY clause.  This routine attempts
+** to adjust the AggInfo object to take advantage of index and to
+** perhaps use the index as a covering index.
+**
+*/
+static void optimizeAggregateUseOfIndexedExpr(
+  Parse *pParse,          /* Parsing context */
+  Select *pSelect,        /* The SELECT statement being processed */
+  AggInfo *pAggInfo,      /* The aggregate info */
+  NameContext *pNC        /* Name context used to resolve agg-func args */
+){
+  assert( pAggInfo->iFirstReg==0 );
+  assert( pSelect!=0 );
+  assert( pSelect->pGroupBy!=0 );
+  pAggInfo->nColumn = pAggInfo->nAccumulator;
+  if( ALWAYS(pAggInfo->nSortingColumn>0) ){
+    int mx = pSelect->pGroupBy->nExpr - 1;
+    int j, k;
+    for(j=0; j<pAggInfo->nColumn; j++){
+      k = pAggInfo->aCol[j].iSorterColumn;
+      if( k>mx ) mx = k;
+    }
+    pAggInfo->nSortingColumn = mx+1;
+  }
+  analyzeAggFuncArgs(pAggInfo, pNC);
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x20 ){
+    IndexedExpr *pIEpr;
+    TREETRACE(0x20, pParse, pSelect,
+        ("AggInfo (possibly) adjusted for Indexed Exprs\n"));
+    sqlite3TreeViewSelect(0, pSelect, 0);
+    for(pIEpr=pParse->pIdxEpr; pIEpr; pIEpr=pIEpr->pIENext){
+      printf("data-cursor=%d index={%d,%d}\n",
+          pIEpr->iDataCur, pIEpr->iIdxCur, pIEpr->iIdxCol);
+      sqlite3TreeViewExpr(0, pIEpr->pExpr, 0);
+    }
+    printAggInfo(pAggInfo);
+  }
+#else
+  UNUSED_PARAMETER(pSelect);
+  UNUSED_PARAMETER(pParse);
+#endif
+}
+
+/*
+** Walker callback for aggregateConvertIndexedExprRefToColumn().
+*/
+static int aggregateIdxEprRefToColCallback(Walker *pWalker, Expr *pExpr){
+  AggInfo *pAggInfo;
+  struct AggInfo_col *pCol;
+  UNUSED_PARAMETER(pWalker);
+  if( pExpr->pAggInfo==0 ) return WRC_Continue;
+  if( pExpr->op==TK_AGG_COLUMN ) return WRC_Continue;
+  if( pExpr->op==TK_AGG_FUNCTION ) return WRC_Continue;
+  if( pExpr->op==TK_IF_NULL_ROW ) return WRC_Continue;
+  pAggInfo = pExpr->pAggInfo;
+  if( NEVER(pExpr->iAgg>=pAggInfo->nColumn) ) return WRC_Continue;
+  assert( pExpr->iAgg>=0 );
+  pCol = &pAggInfo->aCol[pExpr->iAgg];
+  pExpr->op = TK_AGG_COLUMN;
+  pExpr->iTable = pCol->iTable;
+  pExpr->iColumn = pCol->iColumn;
+  ExprClearProperty(pExpr, EP_Skip|EP_Collate|EP_Unlikely);
+  return WRC_Prune;
+}
+
+/*
+** Convert every pAggInfo->aFunc[].pExpr such that any node within
+** those expressions that has pAppInfo set is changed into a TK_AGG_COLUMN
+** opcode.
+*/
+static void aggregateConvertIndexedExprRefToColumn(AggInfo *pAggInfo){
+  int i;
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = aggregateIdxEprRefToColCallback;
+  for(i=0; i<pAggInfo->nFunc; i++){
+    sqlite3WalkExpr(&w, pAggInfo->aFunc[i].pFExpr);
+  }
+}
+
+
+/*
+** Allocate a block of registers so that there is one register for each
+** pAggInfo->aCol[] and pAggInfo->aFunc[] entry in pAggInfo.  The first
+** register in this block is stored in pAggInfo->iFirstReg.
+**
+** This routine may only be called once for each AggInfo object.  Prior
+** to calling this routine:
+**
+**     *  The aCol[] and aFunc[] arrays may be modified
+**     *  The AggInfoColumnReg() and AggInfoFuncReg() macros may not be used
+**
+** After calling this routine:
+**
+**     *  The aCol[] and aFunc[] arrays are fixed
+**     *  The AggInfoColumnReg() and AggInfoFuncReg() macros may be used
+**
+*/
+static void assignAggregateRegisters(Parse *pParse, AggInfo *pAggInfo){
+  assert( pAggInfo!=0 );
+  assert( pAggInfo->iFirstReg==0 );
+  pAggInfo->iFirstReg = pParse->nMem + 1;
+  pParse->nMem += pAggInfo->nColumn + pAggInfo->nFunc;
+}
+
+/*
+** Reset the aggregate accumulator.
+**
+** The aggregate accumulator is a set of memory cells that hold
+** intermediate results while calculating an aggregate.  This
+** routine generates code that stores NULLs in all of those memory
+** cells.
+*/
+static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  struct AggInfo_func *pFunc;
+  int nReg = pAggInfo->nFunc + pAggInfo->nColumn;
+  assert( pAggInfo->iFirstReg>0 );
+  assert( pParse->db->pParse==pParse );
+  assert( pParse->db->mallocFailed==0 || pParse->nErr!=0 );
+  if( nReg==0 ) return;
+  if( pParse->nErr ) return;
+  sqlite3VdbeAddOp3(v, OP_Null, 0, pAggInfo->iFirstReg,
+                    pAggInfo->iFirstReg+nReg-1);
+  for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
+    if( pFunc->iDistinct>=0 ){
+      Expr *pE = pFunc->pFExpr;
+      assert( ExprUseXList(pE) );
+      if( pE->x.pList==0 || pE->x.pList->nExpr!=1 ){
+        sqlite3ErrorMsg(pParse, "DISTINCT aggregates must have exactly one "
+           "argument");
+        pFunc->iDistinct = -1;
+      }else{
+        KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pE->x.pList,0,0);
+        pFunc->iDistAddr = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+            pFunc->iDistinct, 0, 0, (char*)pKeyInfo, P4_KEYINFO);
+        ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s(DISTINCT)",
+                          pFunc->pFunc->zName));
+      }
+    }
+    if( pFunc->iOBTab>=0 ){
+      ExprList *pOBList;
+      KeyInfo *pKeyInfo;
+      int nExtra = 0;
+      assert( pFunc->pFExpr->pLeft!=0 );
+      assert( pFunc->pFExpr->pLeft->op==TK_ORDER );
+      assert( ExprUseXList(pFunc->pFExpr->pLeft) );
+      assert( pFunc->pFunc!=0 );
+      pOBList = pFunc->pFExpr->pLeft->x.pList;
+      if( !pFunc->bOBUnique ){
+        nExtra++;  /* One extra column for the OP_Sequence */
+      }
+      if( pFunc->bOBPayload ){
+        /* extra columns for the function arguments */
+        assert( ExprUseXList(pFunc->pFExpr) );
+        nExtra += pFunc->pFExpr->x.pList->nExpr;
+      }
+      if( pFunc->bUseSubtype ){
+        nExtra += pFunc->pFExpr->x.pList->nExpr;
+      }
+      pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pOBList, 0, nExtra);
+      if( !pFunc->bOBUnique && pParse->nErr==0 ){
+        pKeyInfo->nKeyField++;
+      }
+      sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+            pFunc->iOBTab, pOBList->nExpr+nExtra, 0,
+            (char*)pKeyInfo, P4_KEYINFO);
+      ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s(ORDER BY)",
+                          pFunc->pFunc->zName));
+    }
+  }
+}
+
+/*
+** Invoke the OP_AggFinalize opcode for every aggregate function
+** in the AggInfo structure.
+*/
+static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  struct AggInfo_func *pF;
+  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
+    ExprList *pList;
+    assert( ExprUseXList(pF->pFExpr) );
+    if( pParse->nErr ) return;
+    pList = pF->pFExpr->x.pList;
+    if( pF->iOBTab>=0 ){
+      /* For an ORDER BY aggregate, calls to OP_AggStep were deferred.  Inputs
+      ** were stored in emphermal table pF->iOBTab.  Here, we extract those
+      ** inputs (in ORDER BY order) and make all calls to OP_AggStep
+      ** before doing the OP_AggFinal call. */
+      int iTop;        /* Start of loop for extracting columns */
+      int nArg;        /* Number of columns to extract */
+      int nKey;        /* Key columns to be skipped */
+      int regAgg;      /* Extract into this array */
+      int j;           /* Loop counter */
+
+      assert( pF->pFunc!=0 );
+      nArg = pList->nExpr;
+      regAgg = sqlite3GetTempRange(pParse, nArg);
+
+      if( pF->bOBPayload==0 ){
+        nKey = 0;
+      }else{
+        assert( pF->pFExpr->pLeft!=0 );
+        assert( ExprUseXList(pF->pFExpr->pLeft) );
+        assert( pF->pFExpr->pLeft->x.pList!=0 );
+        nKey = pF->pFExpr->pLeft->x.pList->nExpr;
+        if( ALWAYS(!pF->bOBUnique) ) nKey++;
+      }
+      iTop = sqlite3VdbeAddOp1(v, OP_Rewind, pF->iOBTab); VdbeCoverage(v);
+      for(j=nArg-1; j>=0; j--){
+        sqlite3VdbeAddOp3(v, OP_Column, pF->iOBTab, nKey+j, regAgg+j);
+      }
+      if( pF->bUseSubtype ){
+        int regSubtype = sqlite3GetTempReg(pParse);
+        int iBaseCol = nKey + nArg + (pF->bOBPayload==0 && pF->bOBUnique==0);
+        for(j=nArg-1; j>=0; j--){
+          sqlite3VdbeAddOp3(v, OP_Column, pF->iOBTab, iBaseCol+j, regSubtype);
+          sqlite3VdbeAddOp2(v, OP_SetSubtype, regSubtype, regAgg+j);
+        }
+        sqlite3ReleaseTempReg(pParse, regSubtype);
+      }
+      sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, AggInfoFuncReg(pAggInfo,i));
+      sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
+      sqlite3VdbeChangeP5(v, (u16)nArg);
+      sqlite3VdbeAddOp2(v, OP_Next, pF->iOBTab, iTop+1); VdbeCoverage(v);
+      sqlite3VdbeJumpHere(v, iTop);
+      sqlite3ReleaseTempRange(pParse, regAgg, nArg);
+    }
+    sqlite3VdbeAddOp2(v, OP_AggFinal, AggInfoFuncReg(pAggInfo,i),
+                      pList ? pList->nExpr : 0);
+    sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
+  }
+}
+
+/*
+** Generate code that will update the accumulator memory cells for an
+** aggregate based on the current cursor position.
+**
+** If regAcc is non-zero and there are no min() or max() aggregates
+** in pAggInfo, then only populate the pAggInfo->nAccumulator accumulator
+** registers if register regAcc contains 0. The caller will take care
+** of setting and clearing regAcc.
+**
+** For an ORDER BY aggregate, the actual accumulator memory cell update
+** is deferred until after all input rows have been received, so that they
+** can be run in the requested order.  In that case, instead of invoking
+** OP_AggStep to update the accumulator, just add the arguments that would
+** have been passed into OP_AggStep into the sorting ephemeral table
+** (along with the appropriate sort key).
+*/
+static void updateAccumulator(
+  Parse *pParse,
+  int regAcc,
+  AggInfo *pAggInfo,
+  int eDistinctType
+){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  int regHit = 0;
+  int addrHitTest = 0;
+  struct AggInfo_func *pF;
+  struct AggInfo_col *pC;
+
+  assert( pAggInfo->iFirstReg>0 );
+  if( pParse->nErr ) return;
+  pAggInfo->directMode = 1;
+  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
+    int nArg;
+    int addrNext = 0;
+    int regAgg;
+    int regAggSz = 0;
+    int regDistinct = 0;
+    ExprList *pList;
+    assert( ExprUseXList(pF->pFExpr) );
+    assert( !IsWindowFunc(pF->pFExpr) );
+    assert( pF->pFunc!=0 );
+    pList = pF->pFExpr->x.pList;
+    if( ExprHasProperty(pF->pFExpr, EP_WinFunc) ){
+      Expr *pFilter = pF->pFExpr->y.pWin->pFilter;
+      if( pAggInfo->nAccumulator
+       && (pF->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL)
+       && regAcc
+      ){
+        /* If regAcc==0, there there exists some min() or max() function
+        ** without a FILTER clause that will ensure the magnet registers
+        ** are populated. */
+        if( regHit==0 ) regHit = ++pParse->nMem;
+        /* If this is the first row of the group (regAcc contains 0), clear the
+        ** "magnet" register regHit so that the accumulator registers
+        ** are populated if the FILTER clause jumps over the the
+        ** invocation of min() or max() altogether. Or, if this is not
+        ** the first row (regAcc contains 1), set the magnet register so that
+        ** the accumulators are not populated unless the min()/max() is invoked
+        ** and indicates that they should be.  */
+        sqlite3VdbeAddOp2(v, OP_Copy, regAcc, regHit);
+      }
+      addrNext = sqlite3VdbeMakeLabel(pParse);
+      sqlite3ExprIfFalse(pParse, pFilter, addrNext, SQLITE_JUMPIFNULL);
+    }
+    if( pF->iOBTab>=0 ){
+      /* Instead of invoking AggStep, we must push the arguments that would
+      ** have been passed to AggStep onto the sorting table. */
+      int jj;                /* Registered used so far in building the record */
+      ExprList *pOBList;     /* The ORDER BY clause */
+      assert( pList!=0 );
+      nArg = pList->nExpr;
+      assert( nArg>0 );
+      assert( pF->pFExpr->pLeft!=0 );
+      assert( pF->pFExpr->pLeft->op==TK_ORDER );
+      assert( ExprUseXList(pF->pFExpr->pLeft) );
+      pOBList = pF->pFExpr->pLeft->x.pList;
+      assert( pOBList!=0 );
+      assert( pOBList->nExpr>0 );
+      regAggSz = pOBList->nExpr;
+      if( !pF->bOBUnique ){
+        regAggSz++;   /* One register for OP_Sequence */
+      }
+      if( pF->bOBPayload ){
+        regAggSz += nArg;
+      }
+      if( pF->bUseSubtype ){
+        regAggSz += nArg;
+      }
+      regAggSz++;  /* One extra register to hold result of MakeRecord */
+      regAgg = sqlite3GetTempRange(pParse, regAggSz);
+      regDistinct = regAgg;
+      sqlite3ExprCodeExprList(pParse, pOBList, regAgg, 0, SQLITE_ECEL_DUP);
+      jj = pOBList->nExpr;
+      if( !pF->bOBUnique ){
+        sqlite3VdbeAddOp2(v, OP_Sequence, pF->iOBTab, regAgg+jj);
+        jj++;
+      }
+      if( pF->bOBPayload ){
+        regDistinct = regAgg+jj;
+        sqlite3ExprCodeExprList(pParse, pList, regDistinct, 0, SQLITE_ECEL_DUP);
+        jj += nArg;
+      }
+      if( pF->bUseSubtype ){
+        int kk;
+        int regBase = pF->bOBPayload ? regDistinct : regAgg;
+        for(kk=0; kk<nArg; kk++, jj++){
+          sqlite3VdbeAddOp2(v, OP_GetSubtype, regBase+kk, regAgg+jj);
+        }
+      }
+    }else if( pList ){
+      nArg = pList->nExpr;
+      regAgg = sqlite3GetTempRange(pParse, nArg);
+      regDistinct = regAgg;
+      sqlite3ExprCodeExprList(pParse, pList, regAgg, 0, SQLITE_ECEL_DUP);
+    }else{
+      nArg = 0;
+      regAgg = 0;
+    }
+    if( pF->iDistinct>=0 && pList ){
+      if( addrNext==0 ){
+        addrNext = sqlite3VdbeMakeLabel(pParse);
+      }
+      pF->iDistinct = codeDistinct(pParse, eDistinctType,
+          pF->iDistinct, addrNext, pList, regDistinct);
+    }
+    if( pF->iOBTab>=0 ){
+      /* Insert a new record into the ORDER BY table */
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regAgg, regAggSz-1,
+                        regAgg+regAggSz-1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pF->iOBTab, regAgg+regAggSz-1,
+                           regAgg, regAggSz-1);
+      sqlite3ReleaseTempRange(pParse, regAgg, regAggSz);
+    }else{
+      /* Invoke the AggStep function */
+      if( pF->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){
+        CollSeq *pColl = 0;
+        struct ExprList_item *pItem;
+        int j;
+        assert( pList!=0 );  /* pList!=0 if pF->pFunc has NEEDCOLL */
+        for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
+          pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
+        }
+        if( !pColl ){
+          pColl = pParse->db->pDfltColl;
+        }
+        if( regHit==0 && pAggInfo->nAccumulator ) regHit = ++pParse->nMem;
+        sqlite3VdbeAddOp4(v, OP_CollSeq, regHit, 0, 0,
+                         (char *)pColl, P4_COLLSEQ);
+      }
+      sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, AggInfoFuncReg(pAggInfo,i));
+      sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
+      sqlite3VdbeChangeP5(v, (u16)nArg);
+      sqlite3ReleaseTempRange(pParse, regAgg, nArg);
+    }
+    if( addrNext ){
+      sqlite3VdbeResolveLabel(v, addrNext);
+    }
+    if( pParse->nErr ) return;
+  }
+  if( regHit==0 && pAggInfo->nAccumulator ){
+    regHit = regAcc;
+  }
+  if( regHit ){
+    addrHitTest = sqlite3VdbeAddOp1(v, OP_If, regHit); VdbeCoverage(v);
+  }
+  for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
+    sqlite3ExprCode(pParse, pC->pCExpr, AggInfoColumnReg(pAggInfo,i));
+    if( pParse->nErr ) return;
+  }
+
+  pAggInfo->directMode = 0;
+  if( addrHitTest ){
+    sqlite3VdbeJumpHereOrPopInst(v, addrHitTest);
+  }
+}
+
+/*
+** Add a single OP_Explain instruction to the VDBE to explain a simple
+** count(*) query ("SELECT count(*) FROM pTab").
+*/
+#ifndef SQLITE_OMIT_EXPLAIN
+static void explainSimpleCount(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being queried */
+  Index *pIdx                     /* Index used to optimize scan, or NULL */
+){
+  if( pParse->explain==2 ){
+    int bCover = (pIdx!=0 && (HasRowid(pTab) || !IsPrimaryKeyIndex(pIdx)));
+    sqlite3VdbeExplain(pParse, 0, "SCAN %s%s%s",
+        pTab->zName,
+        bCover ? " USING COVERING INDEX " : "",
+        bCover ? pIdx->zName : ""
+    );
+  }
+}
+#else
+# define explainSimpleCount(a,b,c)
+#endif
+
+/*
+** sqlite3WalkExpr() callback used by havingToWhere().
+**
+** If the node passed to the callback is a TK_AND node, return
+** WRC_Continue to tell sqlite3WalkExpr() to iterate through child nodes.
+**
+** Otherwise, return WRC_Prune. In this case, also check if the
+** sub-expression matches the criteria for being moved to the WHERE
+** clause. If so, add it to the WHERE clause and replace the sub-expression
+** within the HAVING expression with a constant "1".
+*/
+static int havingToWhereExprCb(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op!=TK_AND ){
+    Select *pS = pWalker->u.pSelect;
+    /* This routine is called before the HAVING clause of the current
+    ** SELECT is analyzed for aggregates. So if pExpr->pAggInfo is set
+    ** here, it indicates that the expression is a correlated reference to a
+    ** column from an outer aggregate query, or an aggregate function that
+    ** belongs to an outer query. Do not move the expression to the WHERE
+    ** clause in this obscure case, as doing so may corrupt the outer Select
+    ** statements AggInfo structure.  */
+    if( sqlite3ExprIsConstantOrGroupBy(pWalker->pParse, pExpr, pS->pGroupBy)
+     && ExprAlwaysFalse(pExpr)==0
+     && pExpr->pAggInfo==0
+    ){
+      sqlite3 *db = pWalker->pParse->db;
+      Expr *pNew = sqlite3Expr(db, TK_INTEGER, "1");
+      if( pNew ){
+        Expr *pWhere = pS->pWhere;
+        SWAP(Expr, *pNew, *pExpr);
+        pNew = sqlite3ExprAnd(pWalker->pParse, pWhere, pNew);
+        pS->pWhere = pNew;
+        pWalker->eCode = 1;
+      }
+    }
+    return WRC_Prune;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Transfer eligible terms from the HAVING clause of a query, which is
+** processed after grouping, to the WHERE clause, which is processed before
+** grouping. For example, the query:
+**
+**   SELECT * FROM <tables> WHERE a=? GROUP BY b HAVING b=? AND c=?
+**
+** can be rewritten as:
+**
+**   SELECT * FROM <tables> WHERE a=? AND b=? GROUP BY b HAVING c=?
+**
+** A term of the HAVING expression is eligible for transfer if it consists
+** entirely of constants and expressions that are also GROUP BY terms that
+** use the "BINARY" collation sequence.
+*/
+static void havingToWhere(Parse *pParse, Select *p){
+  Walker sWalker;
+  memset(&sWalker, 0, sizeof(sWalker));
+  sWalker.pParse = pParse;
+  sWalker.xExprCallback = havingToWhereExprCb;
+  sWalker.u.pSelect = p;
+  sqlite3WalkExpr(&sWalker, p->pHaving);
+#if TREETRACE_ENABLED
+  if( sWalker.eCode && (sqlite3TreeTrace & 0x100)!=0 ){
+    TREETRACE(0x100,pParse,p,("Move HAVING terms into WHERE:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+}
+
+/*
+** Check to see if the pThis entry of pTabList is a self-join of another view.
+** Search FROM-clause entries in the range of iFirst..iEnd, including iFirst
+** but stopping before iEnd.
+**
+** If pThis is a self-join, then return the SrcItem for the first other
+** instance of that view found.  If pThis is not a self-join then return 0.
+*/
+static SrcItem *isSelfJoinView(
+  SrcList *pTabList,           /* Search for self-joins in this FROM clause */
+  SrcItem *pThis,              /* Search for prior reference to this subquery */
+  int iFirst, int iEnd        /* Range of FROM-clause entries to search. */
+){
+  SrcItem *pItem;
+  Select *pSel;
+  assert( pThis->fg.isSubquery );
+  pSel = pThis->u4.pSubq->pSelect;
+  assert( pSel!=0 );
+  if( pSel->selFlags & SF_PushDown ) return 0;
+  while( iFirst<iEnd ){
+    Select *pS1;
+    pItem = &pTabList->a[iFirst++];
+    if( !pItem->fg.isSubquery ) continue;
+    if( pItem->fg.viaCoroutine ) continue;
+    if( pItem->zName==0 ) continue;
+    assert( pItem->pSTab!=0 );
+    assert( pThis->pSTab!=0 );
+    if( pItem->pSTab->pSchema!=pThis->pSTab->pSchema ) continue;
+    if( sqlite3_stricmp(pItem->zName, pThis->zName)!=0 ) continue;
+    pS1 = pItem->u4.pSubq->pSelect;
+    if( pItem->pSTab->pSchema==0 && pSel->selId!=pS1->selId ){
+      /* The query flattener left two different CTE tables with identical
+      ** names in the same FROM clause. */
+      continue;
+    }
+    if( pS1->selFlags & SF_PushDown ){
+      /* The view was modified by some other optimization such as
+      ** pushDownWhereTerms() */
+      continue;
+    }
+    return pItem;
+  }
+  return 0;
+}
+
+/*
+** Deallocate a single AggInfo object
+*/
+static void agginfoFree(sqlite3 *db, void *pArg){
+  AggInfo *p = (AggInfo*)pArg;
+  sqlite3DbFree(db, p->aCol);
+  sqlite3DbFree(db, p->aFunc);
+  sqlite3DbFreeNN(db, p);
+}
+
+/*
+** Attempt to transform a query of the form
+**
+**    SELECT count(*) FROM (SELECT x FROM t1 UNION ALL SELECT y FROM t2)
+**
+** Into this:
+**
+**    SELECT (SELECT count(*) FROM t1)+(SELECT count(*) FROM t2)
+**
+** The transformation only works if all of the following are true:
+**
+**   *  The subquery is a UNION ALL of two or more terms
+**   *  The subquery does not have a LIMIT clause
+**   *  There is no WHERE or GROUP BY or HAVING clauses on the subqueries
+**   *  The outer query is a simple count(*) with no WHERE clause or other
+**      extraneous syntax.
+**   *  None of the subqueries are DISTINCT (forumpost/a860f5fb2e 2025-03-10)
+**
+** Return TRUE if the optimization is undertaken.
+*/
+static int countOfViewOptimization(Parse *pParse, Select *p){
+  Select *pSub, *pPrior;
+  Expr *pExpr;
+  Expr *pCount;
+  sqlite3 *db;
+  SrcItem *pFrom;
+  if( (p->selFlags & SF_Aggregate)==0 ) return 0;   /* This is an aggregate */
+  if( p->pEList->nExpr!=1 ) return 0;               /* Single result column */
+  if( p->pWhere ) return 0;
+  if( p->pHaving ) return 0;
+  if( p->pGroupBy ) return 0;
+  if( p->pOrderBy ) return 0;
+  pExpr = p->pEList->a[0].pExpr;
+  if( pExpr->op!=TK_AGG_FUNCTION ) return 0;        /* Result is an aggregate */
+  assert( ExprUseUToken(pExpr) );
+  if( sqlite3_stricmp(pExpr->u.zToken,"count") ) return 0;  /* Is count() */
+  assert( ExprUseXList(pExpr) );
+  if( pExpr->x.pList!=0 ) return 0;                 /* Must be count(*) */
+  if( p->pSrc->nSrc!=1 ) return 0;                  /* One table in FROM  */
+  if( ExprHasProperty(pExpr, EP_WinFunc) ) return 0;/* Not a window function */
+  pFrom = p->pSrc->a;
+  if( pFrom->fg.isSubquery==0 ) return 0;    /* FROM is a subquery */
+  pSub = pFrom->u4.pSubq->pSelect;
+  if( pSub->pPrior==0 ) return 0;                   /* Must be a compound */
+  if( pSub->selFlags & SF_CopyCte ) return 0;       /* Not a CTE */
+  do{
+    if( pSub->op!=TK_ALL && pSub->pPrior ) return 0;  /* Must be UNION ALL */
+    if( pSub->pWhere ) return 0;                      /* No WHERE clause */
+    if( pSub->pLimit ) return 0;                      /* No LIMIT clause */
+    if( pSub->selFlags & (SF_Aggregate|SF_Distinct) ){
+       testcase( pSub->selFlags & SF_Aggregate );
+       testcase( pSub->selFlags & SF_Distinct );
+       return 0;     /* Not an aggregate nor DISTINCT */
+    }
+    assert( pSub->pHaving==0 );  /* Due to the previous */
+    pSub = pSub->pPrior;                              /* Repeat over compound */
+  }while( pSub );
+
+  /* If we reach this point then it is OK to perform the transformation */
+
+  db = pParse->db;
+  pCount = pExpr;
+  pExpr = 0;
+  pSub = sqlite3SubqueryDetach(db, pFrom);
+  sqlite3SrcListDelete(db, p->pSrc);
+  p->pSrc = sqlite3DbMallocZero(pParse->db, sizeof(*p->pSrc));
+  while( pSub ){
+    Expr *pTerm;
+    pPrior = pSub->pPrior;
+    pSub->pPrior = 0;
+    pSub->pNext = 0;
+    pSub->selFlags |= SF_Aggregate;
+    pSub->selFlags &= ~SF_Compound;
+    pSub->nSelectRow = 0;
+    sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric, pSub->pEList);
+    pTerm = pPrior ? sqlite3ExprDup(db, pCount, 0) : pCount;
+    pSub->pEList = sqlite3ExprListAppend(pParse, 0, pTerm);
+    pTerm = sqlite3PExpr(pParse, TK_SELECT, 0, 0);
+    sqlite3PExprAddSelect(pParse, pTerm, pSub);
+    if( pExpr==0 ){
+      pExpr = pTerm;
+    }else{
+      pExpr = sqlite3PExpr(pParse, TK_PLUS, pTerm, pExpr);
+    }
+    pSub = pPrior;
+  }
+  p->pEList->a[0].pExpr = pExpr;
+  p->selFlags &= ~SF_Aggregate;
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x200 ){
+    TREETRACE(0x200,pParse,p,("After count-of-view optimization:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+  return 1;
+}
+
+/*
+** If any term of pSrc, or any SF_NestedFrom sub-query, is not the same
+** as pSrcItem but has the same alias as p0, then return true.
+** Otherwise return false.
+*/
+static int sameSrcAlias(SrcItem *p0, SrcList *pSrc){
+  int i;
+  for(i=0; i<pSrc->nSrc; i++){
+    SrcItem *p1 = &pSrc->a[i];
+    if( p1==p0 ) continue;
+    if( p0->pSTab==p1->pSTab && 0==sqlite3_stricmp(p0->zAlias, p1->zAlias) ){
+      return 1;
+    }
+    if( p1->fg.isSubquery
+     && (p1->u4.pSubq->pSelect->selFlags & SF_NestedFrom)!=0
+     && sameSrcAlias(p0, p1->u4.pSubq->pSelect->pSrc)
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Return TRUE (non-zero) if the i-th entry in the pTabList SrcList can
+** be implemented as a co-routine.  The i-th entry is guaranteed to be
+** a subquery.
+**
+** The subquery is implemented as a co-routine if all of the following are
+** true:
+**
+**    (1)  The subquery will likely be implemented in the outer loop of
+**         the query.  This will be the case if any one of the following
+**         conditions hold:
+**         (a)  The subquery is the only term in the FROM clause
+**         (b)  The subquery is the left-most term and a CROSS JOIN or similar
+**              requires it to be the outer loop
+**         (c)  All of the following are true:
+**                (i) The subquery is the left-most subquery in the FROM clause
+**               (ii) There is nothing that would prevent the subquery from
+**                    being used as the outer loop if the sqlite3WhereBegin()
+**                    routine nominates it to that position.
+**              (iii) The query is not a UPDATE ... FROM
+**    (2)  The subquery is not a CTE that should be materialized because
+**         (a) the AS MATERIALIZED keyword is used, or
+**         (b) the CTE is used multiple times and does not have the
+**             NOT MATERIALIZED keyword
+**    (3)  The subquery is not part of a left operand for a RIGHT JOIN
+**    (4)  The SQLITE_Coroutine optimization disable flag is not set
+**    (5)  The subquery is not self-joined
+*/
+static int fromClauseTermCanBeCoroutine(
+  Parse *pParse,          /* Parsing context */
+  SrcList *pTabList,      /* FROM clause */
+  int i,                  /* Which term of the FROM clause holds the subquery */
+  int selFlags            /* Flags on the SELECT statement */
+){
+  SrcItem *pItem = &pTabList->a[i];
+  if( pItem->fg.isCte ){
+    const CteUse *pCteUse = pItem->u2.pCteUse;
+    if( pCteUse->eM10d==M10d_Yes ) return 0;                          /* (2a) */
+    if( pCteUse->nUse>=2 && pCteUse->eM10d!=M10d_No ) return 0;       /* (2b) */
+  }
+  if( pTabList->a[0].fg.jointype & JT_LTORJ ) return 0;               /* (3)  */
+  if( OptimizationDisabled(pParse->db, SQLITE_Coroutines) ) return 0; /* (4)  */
+  if( isSelfJoinView(pTabList, pItem, i+1, pTabList->nSrc)!=0 ){
+    return 0;                                                          /* (5) */
+  }
+  if( i==0 ){
+    if( pTabList->nSrc==1 ) return 1;                             /* (1a) */
+    if( pTabList->a[1].fg.jointype & JT_CROSS ) return 1;         /* (1b) */
+    if( selFlags & SF_UpdateFrom )              return 0;         /* (1c-iii) */
+    return 1;
+  }
+  if( selFlags & SF_UpdateFrom ) return 0;                        /* (1c-iii) */
+  while( 1 /*exit-by-break*/ ){
+    if( pItem->fg.jointype & (JT_OUTER|JT_CROSS)  ) return 0;     /* (1c-ii) */
+    if( i==0 ) break;
+    i--;
+    pItem--;
+    if( pItem->fg.isSubquery ) return 0;                          /* (1c-i) */
+  }
+  return 1;
+}
+
+/*
+** Generate byte-code for the SELECT statement given in the p argument.
+**
+** The results are returned according to the SelectDest structure.
+** See comments in sqliteInt.h for further information.
+**
+** This routine returns the number of errors.  If any errors are
+** encountered, then an appropriate error message is left in
+** pParse->zErrMsg.
+**
+** This routine does NOT free the Select structure passed in.  The
+** calling function needs to do that.
+**
+** This is a long function.  The following is an outline of the processing
+** steps, with tags referencing various milestones:
+**
+**  *  Resolve names and similar preparation                tag-select-0100
+**  *  Scan of the FROM clause                              tag-select-0200
+**      +  OUTER JOIN strength reduction                      tag-select-0220
+**      +  Sub-query ORDER BY removal                         tag-select-0230
+**      +  Query flattening                                   tag-select-0240
+**  *  Separate subroutine for compound-SELECT              tag-select-0300
+**  *  WHERE-clause constant propagation                    tag-select-0330
+**  *  Count()-of-VIEW optimization                         tag-select-0350
+**  *  Scan of the FROM clause again                        tag-select-0400
+**      +  Authorize unreferenced tables                      tag-select-0410
+**      +  Predicate push-down optimization                   tag-select-0420
+**      +  Omit unused subquery columns optimization          tag-select-0440
+**      +  Generate code to implement subqueries              tag-select-0480
+**         -  Co-routines                                       tag-select-0482
+**         -  Reuse previously computed CTE                     tag-select-0484
+**         -  REuse previously computed VIEW                    tag-select-0486
+**         -  Materialize a VIEW or CTE                         tag-select-0488
+**  *  DISTINCT ORDER BY -> GROUP BY optimization           tag-select-0500
+**  *  Set up for ORDER BY                                  tag-select-0600
+**  *  Create output table                                  tag-select-0630
+**  *  Prepare registers for LIMIT                          tag-select-0650
+**  *  Setup for DISTINCT                                   tag-select-0680
+**  *  Generate code for non-aggregate and non-GROUP BY     tag-select-0700
+**  *  Generate code for aggregate and/or GROUP BY          tag-select-0800
+**      +  GROUP BY queries                                   tag-select-0810
+**      +  non-GROUP BY queries                               tag-select-0820
+**         -  Special case of count() w/o GROUP BY              tag-select-0821
+**         -  General case of non-GROUP BY aggregates           tag-select-0822
+**  *  Sort results, as needed                              tag-select-0900
+**  *  Internal self-checks                                 tag-select-1000
+*/
+SQLITE_PRIVATE int sqlite3Select(
+  Parse *pParse,         /* The parser context */
+  Select *p,             /* The SELECT statement being coded. */
+  SelectDest *pDest      /* What to do with the query results */
+){
+  int i, j;              /* Loop counters */
+  WhereInfo *pWInfo;     /* Return from sqlite3WhereBegin() */
+  Vdbe *v;               /* The virtual machine under construction */
+  int isAgg;             /* True for select lists like "count(*)" */
+  ExprList *pEList = 0;  /* List of columns to extract. */
+  SrcList *pTabList;     /* List of tables to select from */
+  Expr *pWhere;          /* The WHERE clause.  May be NULL */
+  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
+  Expr *pHaving;         /* The HAVING clause.  May be NULL */
+  AggInfo *pAggInfo = 0; /* Aggregate information */
+  int rc = 1;            /* Value to return from this function */
+  DistinctCtx sDistinct; /* Info on how to code the DISTINCT keyword */
+  SortCtx sSort;         /* Info on how to code the ORDER BY clause */
+  int iEnd;              /* Address of the end of the query */
+  sqlite3 *db;           /* The database connection */
+  ExprList *pMinMaxOrderBy = 0;  /* Added ORDER BY for min/max queries */
+  u8 minMaxFlag;                 /* Flag for min/max queries */
+
+  db = pParse->db;
+  assert( pParse==db->pParse );
+  v = sqlite3GetVdbe(pParse);
+  if( p==0 || pParse->nErr ){
+    return 1;
+  }
+  assert( db->mallocFailed==0 );
+  if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
+#if TREETRACE_ENABLED
+  TREETRACE(0x1,pParse,p, ("begin processing:\n", pParse->addrExplain));
+  if( sqlite3TreeTrace & 0x10000 ){
+    if( (sqlite3TreeTrace & 0x10001)==0x10000 ){
+      sqlite3TreeViewLine(0, "In sqlite3Select() at %s:%d",
+                           __FILE__, __LINE__);
+    }
+    sqlite3ShowSelect(p);
+  }
+#endif
+
+  /* tag-select-0100 */
+  assert( p->pOrderBy==0 || pDest->eDest!=SRT_DistFifo );
+  assert( p->pOrderBy==0 || pDest->eDest!=SRT_Fifo );
+  assert( p->pOrderBy==0 || pDest->eDest!=SRT_DistQueue );
+  assert( p->pOrderBy==0 || pDest->eDest!=SRT_Queue );
+  if( IgnorableDistinct(pDest) ){
+    assert(pDest->eDest==SRT_Exists     || pDest->eDest==SRT_Union ||
+           pDest->eDest==SRT_Except     || pDest->eDest==SRT_Discard ||
+           pDest->eDest==SRT_DistQueue  || pDest->eDest==SRT_DistFifo );
+    /* All of these destinations are also able to ignore the ORDER BY clause */
+    if( p->pOrderBy ){
+#if TREETRACE_ENABLED
+      TREETRACE(0x800,pParse,p, ("dropping superfluous ORDER BY:\n"));
+      if( sqlite3TreeTrace & 0x800 ){
+        sqlite3TreeViewExprList(0, p->pOrderBy, 0, "ORDERBY");
+      }
+#endif
+      sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric,
+                              p->pOrderBy);
+      testcase( pParse->earlyCleanup );
+      p->pOrderBy = 0;
+    }
+    p->selFlags &= ~SF_Distinct;
+    p->selFlags |= SF_NoopOrderBy;
+  }
+  sqlite3SelectPrep(pParse, p, 0);
+  if( pParse->nErr ){
+    goto select_end;
+  }
+  assert( db->mallocFailed==0 );
+  assert( p->pEList!=0 );
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x10 ){
+    TREETRACE(0x10,pParse,p, ("after name resolution:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+
+  /* If the SF_UFSrcCheck flag is set, then this function is being called
+  ** as part of populating the temp table for an UPDATE...FROM statement.
+  ** In this case, it is an error if the target object (pSrc->a[0]) name
+  ** or alias is duplicated within FROM clause (pSrc->a[1..n]).
+  **
+  ** Postgres disallows this case too. The reason is that some other
+  ** systems handle this case differently, and not all the same way,
+  ** which is just confusing. To avoid this, we follow PG's lead and
+  ** disallow it altogether.  */
+  if( p->selFlags & SF_UFSrcCheck ){
+    SrcItem *p0 = &p->pSrc->a[0];
+    if( sameSrcAlias(p0, p->pSrc) ){
+      sqlite3ErrorMsg(pParse,
+          "target object/alias may not appear in FROM clause: %s",
+          p0->zAlias ? p0->zAlias : p0->pSTab->zName
+      );
+      goto select_end;
+    }
+
+    /* Clear the SF_UFSrcCheck flag. The check has already been performed,
+    ** and leaving this flag set can cause errors if a compound sub-query
+    ** in p->pSrc is flattened into this query and this function called
+    ** again as part of compound SELECT processing.  */
+    p->selFlags &= ~SF_UFSrcCheck;
+  }
+
+  if( pDest->eDest==SRT_Output ){
+    sqlite3GenerateColumnNames(pParse, p);
+  }
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( sqlite3WindowRewrite(pParse, p) ){
+    assert( pParse->nErr );
+    goto select_end;
+  }
+#if TREETRACE_ENABLED
+  if( p->pWin && (sqlite3TreeTrace & 0x40)!=0 ){
+    TREETRACE(0x40,pParse,p, ("after window rewrite:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+  pTabList = p->pSrc;
+  isAgg = (p->selFlags & SF_Aggregate)!=0;
+  memset(&sSort, 0, sizeof(sSort));
+  sSort.pOrderBy = p->pOrderBy;
+
+  /* Try to do various optimizations (flattening subqueries, and strength
+  ** reduction of join operators) in the FROM clause up into the main query
+  ** tag-select-0200
+  */
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+  for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
+    SrcItem *pItem = &pTabList->a[i];
+    Select *pSub = pItem->fg.isSubquery ? pItem->u4.pSubq->pSelect : 0;
+    Table *pTab = pItem->pSTab;
+
+    /* The expander should have already created transient Table objects
+    ** even for FROM clause elements such as subqueries that do not correspond
+    ** to a real table */
+    assert( pTab!=0 );
+
+    /* Try to simplify joins:
+    **
+    **      LEFT JOIN  ->  JOIN
+    **     RIGHT JOIN  ->  JOIN
+    **      FULL JOIN  ->  RIGHT JOIN
+    **
+    ** If terms of the i-th table are used in the WHERE clause in such a
+    ** way that the i-th table cannot be the NULL row of a join, then
+    ** perform the appropriate simplification. This is called
+    ** "OUTER JOIN strength reduction" in the SQLite documentation.
+    ** tag-select-0220
+    */
+    if( (pItem->fg.jointype & (JT_LEFT|JT_LTORJ))!=0
+     && sqlite3ExprImpliesNonNullRow(p->pWhere, pItem->iCursor,
+                                     pItem->fg.jointype & JT_LTORJ)
+     && OptimizationEnabled(db, SQLITE_SimplifyJoin)
+    ){
+      if( pItem->fg.jointype & JT_LEFT ){
+        if( pItem->fg.jointype & JT_RIGHT ){
+          TREETRACE(0x1000,pParse,p,
+                    ("FULL-JOIN simplifies to RIGHT-JOIN on term %d\n",i));
+          pItem->fg.jointype &= ~JT_LEFT;
+        }else{
+          TREETRACE(0x1000,pParse,p,
+                    ("LEFT-JOIN simplifies to JOIN on term %d\n",i));
+          pItem->fg.jointype &= ~(JT_LEFT|JT_OUTER);
+          unsetJoinExpr(p->pWhere, pItem->iCursor, 0);
+        }
+      }
+      if( pItem->fg.jointype & JT_LTORJ ){
+        for(j=i+1; j<pTabList->nSrc; j++){
+          SrcItem *pI2 = &pTabList->a[j];
+          if( pI2->fg.jointype & JT_RIGHT ){
+            if( pI2->fg.jointype & JT_LEFT ){
+              TREETRACE(0x1000,pParse,p,
+                        ("FULL-JOIN simplifies to LEFT-JOIN on term %d\n",j));
+              pI2->fg.jointype &= ~JT_RIGHT;
+            }else{
+              TREETRACE(0x1000,pParse,p,
+                        ("RIGHT-JOIN simplifies to JOIN on term %d\n",j));
+              pI2->fg.jointype &= ~(JT_RIGHT|JT_OUTER);
+              unsetJoinExpr(p->pWhere, pI2->iCursor, 1);
+            }
+          }
+        }
+        for(j=pTabList->nSrc-1; j>=0; j--){
+          pTabList->a[j].fg.jointype &= ~JT_LTORJ;
+          if( pTabList->a[j].fg.jointype & JT_RIGHT ) break;
+        }
+      }
+    }
+
+    /* No further action if this term of the FROM clause is not a subquery */
+    if( pSub==0 ) continue;
+
+    /* Catch mismatch in the declared columns of a view and the number of
+    ** columns in the SELECT on the RHS */
+    if( pTab->nCol!=pSub->pEList->nExpr ){
+      sqlite3ErrorMsg(pParse, "expected %d columns for '%s' but got %d",
+                      pTab->nCol, pTab->zName, pSub->pEList->nExpr);
+      goto select_end;
+    }
+
+    /* Do not attempt the usual optimizations (flattening and ORDER BY
+    ** elimination) on a MATERIALIZED common table expression because
+    ** a MATERIALIZED common table expression is an optimization fence.
+    */
+    if( pItem->fg.isCte && pItem->u2.pCteUse->eM10d==M10d_Yes ){
+      continue;
+    }
+
+    /* Do not try to flatten an aggregate subquery.
+    **
+    ** Flattening an aggregate subquery is only possible if the outer query
+    ** is not a join.  But if the outer query is not a join, then the subquery
+    ** will be implemented as a co-routine and there is no advantage to
+    ** flattening in that case.
+    */
+    if( (pSub->selFlags & SF_Aggregate)!=0 ) continue;
+    assert( pSub->pGroupBy==0 );
+
+    /* tag-select-0230:
+    ** If a FROM-clause subquery has an ORDER BY clause that is not
+    ** really doing anything, then delete it now so that it does not
+    ** interfere with query flattening.  See the discussion at
+    ** https://sqlite.org/forum/forumpost/2d76f2bcf65d256a
+    **
+    ** Beware of these cases where the ORDER BY clause may not be safely
+    ** omitted:
+    **
+    **    (1)   There is also a LIMIT clause
+    **    (2)   The subquery was added to help with window-function
+    **          processing
+    **    (3)   The subquery is in the FROM clause of an UPDATE
+    **    (4)   The outer query uses an aggregate function other than
+    **          the built-in count(), min(), or max().
+    **    (5)   The ORDER BY isn't going to accomplish anything because
+    **          one of:
+    **            (a)  The outer query has a different ORDER BY clause
+    **            (b)  The subquery is part of a join
+    **          See forum post 062d576715d277c8
+    **    (6)   The subquery is not a recursive CTE.  ORDER BY has a different
+    **          meaning for recursive CTEs and this optimization does not
+    **          apply.
+    **
+    ** Also retain the ORDER BY if the OmitOrderBy optimization is disabled.
+    */
+    if( pSub->pOrderBy!=0
+     && (p->pOrderBy!=0 || pTabList->nSrc>1)      /* Condition (5) */
+     && pSub->pLimit==0                           /* Condition (1) */
+     && (pSub->selFlags & (SF_OrderByReqd|SF_Recursive))==0  /* (2) and (6) */
+     && (p->selFlags & SF_OrderByReqd)==0         /* Condition (3) and (4) */
+     && OptimizationEnabled(db, SQLITE_OmitOrderBy)
+    ){
+      TREETRACE(0x800,pParse,p,
+                ("omit superfluous ORDER BY on %r FROM-clause subquery\n",i+1));
+      sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric,
+                              pSub->pOrderBy);
+      pSub->pOrderBy = 0;
+    }
+
+    /* If the outer query contains a "complex" result set (that is,
+    ** if the result set of the outer query uses functions or subqueries)
+    ** and if the subquery contains an ORDER BY clause and if
+    ** it will be implemented as a co-routine, then do not flatten.  This
+    ** restriction allows SQL constructs like this:
+    **
+    **  SELECT expensive_function(x)
+    **    FROM (SELECT x FROM tab ORDER BY y LIMIT 10);
+    **
+    ** The expensive_function() is only computed on the 10 rows that
+    ** are output, rather than every row of the table.
+    **
+    ** The requirement that the outer query have a complex result set
+    ** means that flattening does occur on simpler SQL constraints without
+    ** the expensive_function() like:
+    **
+    **  SELECT x FROM (SELECT x FROM tab ORDER BY y LIMIT 10);
+    */
+    if( pSub->pOrderBy!=0
+     && i==0
+     && (p->selFlags & SF_ComplexResult)!=0
+     && (pTabList->nSrc==1
+         || (pTabList->a[1].fg.jointype&(JT_OUTER|JT_CROSS))!=0)
+    ){
+      continue;
+    }
+
+    /* tag-select-0240 */
+    if( flattenSubquery(pParse, p, i, isAgg) ){
+      if( pParse->nErr ) goto select_end;
+      /* This subquery can be absorbed into its parent. */
+      i = -1;
+    }
+    pTabList = p->pSrc;
+    if( db->mallocFailed ) goto select_end;
+    if( !IgnorableOrderby(pDest) ){
+      sSort.pOrderBy = p->pOrderBy;
+    }
+  }
+#endif
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+  /* Handle compound SELECT statements using the separate multiSelect()
+  ** procedure.  tag-select-0300
+  */
+  if( p->pPrior ){
+    rc = multiSelect(pParse, p, pDest);
+#if TREETRACE_ENABLED
+    TREETRACE(0x400,pParse,p,("end compound-select processing\n"));
+    if( (sqlite3TreeTrace & 0x400)!=0 && ExplainQueryPlanParent(pParse)==0 ){
+      sqlite3TreeViewSelect(0, p, 0);
+    }
+#endif
+    if( p->pNext==0 ) ExplainQueryPlanPop(pParse);
+    return rc;
+  }
+#endif
+
+  /* Do the WHERE-clause constant propagation optimization if this is
+  ** a join.  No need to spend time on this operation for non-join queries
+  ** as the equivalent optimization will be handled by query planner in
+  ** sqlite3WhereBegin().  tag-select-0330
+  */
+  if( p->pWhere!=0
+   && p->pWhere->op==TK_AND
+   && OptimizationEnabled(db, SQLITE_PropagateConst)
+   && propagateConstants(pParse, p)
+  ){
+#if TREETRACE_ENABLED
+    if( sqlite3TreeTrace & 0x2000 ){
+      TREETRACE(0x2000,pParse,p,("After constant propagation:\n"));
+      sqlite3TreeViewSelect(0, p, 0);
+    }
+#endif
+  }else{
+    TREETRACE(0x2000,pParse,p,("Constant propagation not helpful\n"));
+  }
+
+  /* tag-select-0350 */
+  if( OptimizationEnabled(db, SQLITE_QueryFlattener|SQLITE_CountOfView)
+   && countOfViewOptimization(pParse, p)
+  ){
+    if( db->mallocFailed ) goto select_end;
+    pTabList = p->pSrc;
+  }
+
+  /* Loop over all terms in the FROM clause and do two things for each term:
+  **
+  **   (1) Authorize unreferenced tables
+  **   (2) Generate code for all sub-queries
+  **
+  ** tag-select-0400
+  */
+  for(i=0; i<pTabList->nSrc; i++){
+    SrcItem *pItem = &pTabList->a[i];
+    SrcItem *pPrior;
+    SelectDest dest;
+    Subquery *pSubq;
+    Select *pSub;
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+    const char *zSavedAuthContext;
+#endif
+
+    /* Authorized unreferenced tables.  tag-select-0410
+    **
+    ** Issue SQLITE_READ authorizations with a fake column name for any
+    ** tables that are referenced but from which no values are extracted.
+    ** Examples of where these kinds of null SQLITE_READ authorizations
+    ** would occur:
+    **
+    **     SELECT count(*) FROM t1;   -- SQLITE_READ t1.""
+    **     SELECT t1.* FROM t1, t2;   -- SQLITE_READ t2.""
+    **
+    ** The fake column name is an empty string.  It is possible for a table to
+    ** have a column named by the empty string, in which case there is no way to
+    ** distinguish between an unreferenced table and an actual reference to the
+    ** "" column. The original design was for the fake column name to be a NULL,
+    ** which would be unambiguous.  But legacy authorization callbacks might
+    ** assume the column name is non-NULL and segfault.  The use of an empty
+    ** string for the fake column name seems safer.
+    */
+    if( pItem->colUsed==0 && pItem->zName!=0 ){
+      const char *zDb;
+      if( pItem->fg.fixedSchema ){
+        int iDb = sqlite3SchemaToIndex(pParse->db, pItem->u4.pSchema);
+        zDb = db->aDb[iDb].zDbSName;
+      }else if( pItem->fg.isSubquery ){
+        zDb = 0;
+      }else{
+        zDb = pItem->u4.zDatabase;
+      }
+      sqlite3AuthCheck(pParse, SQLITE_READ, pItem->zName, "", zDb);
+    }
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+    /* Generate code for all sub-queries in the FROM clause
+    */
+    if( pItem->fg.isSubquery==0 ) continue;
+    pSubq = pItem->u4.pSubq;
+    assert( pSubq!=0 );
+    pSub = pSubq->pSelect;
+
+    /* The code for a subquery should only be generated once. */
+    if( pSubq->addrFillSub!=0 ) continue;
+
+    /* Increment Parse.nHeight by the height of the largest expression
+    ** tree referred to by this, the parent select. The child select
+    ** may contain expression trees of at most
+    ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
+    ** more conservative than necessary, but much easier than enforcing
+    ** an exact limit.
+    */
+    pParse->nHeight += sqlite3SelectExprHeight(p);
+
+    /* Make copies of constant WHERE-clause terms in the outer query down
+    ** inside the subquery.  This can help the subquery to run more efficiently.
+    ** This is the "predicate push-down optimization".  tag-select-0420
+    */
+    if( OptimizationEnabled(db, SQLITE_PushDown)
+     && (pItem->fg.isCte==0
+         || (pItem->u2.pCteUse->eM10d!=M10d_Yes && pItem->u2.pCteUse->nUse<2))
+     && pushDownWhereTerms(pParse, pSub, p->pWhere, pTabList, i)
+    ){
+#if TREETRACE_ENABLED
+      if( sqlite3TreeTrace & 0x4000 ){
+        TREETRACE(0x4000,pParse,p,
+            ("After WHERE-clause push-down into subquery %d:\n", pSub->selId));
+        sqlite3TreeViewSelect(0, p, 0);
+      }
+#endif
+      assert( pSubq->pSelect && (pSub->selFlags & SF_PushDown)!=0 );
+    }else{
+      TREETRACE(0x4000,pParse,p,("WHERE-clause push-down not possible\n"));
+    }
+
+    /* Convert unused result columns of the subquery into simple NULL
+    ** expressions, to avoid unneeded searching and computation.
+    ** tag-select-0440
+    */
+    if( OptimizationEnabled(db, SQLITE_NullUnusedCols)
+     && disableUnusedSubqueryResultColumns(pItem)
+    ){
+#if TREETRACE_ENABLED
+      if( sqlite3TreeTrace & 0x4000 ){
+        TREETRACE(0x4000,pParse,p,
+            ("Change unused result columns to NULL for subquery %d:\n",
+             pSub->selId));
+        sqlite3TreeViewSelect(0, p, 0);
+      }
+#endif
+    }
+
+    zSavedAuthContext = pParse->zAuthContext;
+    pParse->zAuthContext = pItem->zName;
+
+    /* Generate byte-code to implement the subquery  tag-select-0480
+    */
+    if( fromClauseTermCanBeCoroutine(pParse, pTabList, i, p->selFlags) ){
+      /* Implement a co-routine that will return a single row of the result
+      ** set on each invocation.  tag-select-0482
+      */
+      int addrTop = sqlite3VdbeCurrentAddr(v)+1;
+
+      pSubq->regReturn = ++pParse->nMem;
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pSubq->regReturn, 0, addrTop);
+      VdbeComment((v, "%!S", pItem));
+      pSubq->addrFillSub = addrTop;
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, pSubq->regReturn);
+      ExplainQueryPlan((pParse, 1, "CO-ROUTINE %!S", pItem));
+      sqlite3Select(pParse, pSub, &dest);
+      pItem->pSTab->nRowLogEst = pSub->nSelectRow;
+      pItem->fg.viaCoroutine = 1;
+      pSubq->regResult = dest.iSdst;
+      sqlite3VdbeEndCoroutine(v, pSubq->regReturn);
+      VdbeComment((v, "end %!S", pItem));
+      sqlite3VdbeJumpHere(v, addrTop-1);
+      sqlite3ClearTempRegCache(pParse);
+    }else if( pItem->fg.isCte && pItem->u2.pCteUse->addrM9e>0 ){
+      /* This is a CTE for which materialization code has already been
+      ** generated.  Invoke the subroutine to compute the materialization,
+      ** then make the pItem->iCursor be a copy of the ephemeral table that
+      ** holds the result of the materialization. tag-select-0484 */
+      CteUse *pCteUse = pItem->u2.pCteUse;
+      sqlite3VdbeAddOp2(v, OP_Gosub, pCteUse->regRtn, pCteUse->addrM9e);
+      if( pItem->iCursor!=pCteUse->iCur ){
+        sqlite3VdbeAddOp2(v, OP_OpenDup, pItem->iCursor, pCteUse->iCur);
+        VdbeComment((v, "%!S", pItem));
+      }
+      pSub->nSelectRow = pCteUse->nRowEst;
+    }else if( (pPrior = isSelfJoinView(pTabList, pItem, 0, i))!=0 ){
+      /* This view has already been materialized by a prior entry in
+      ** this same FROM clause.  Reuse it.  tag-select-0486 */
+      Subquery *pPriorSubq;
+      assert( pPrior->fg.isSubquery );
+      pPriorSubq = pPrior->u4.pSubq;
+      assert( pPriorSubq!=0 );
+      if( pPriorSubq->addrFillSub ){
+        sqlite3VdbeAddOp2(v, OP_Gosub, pPriorSubq->regReturn,
+                                       pPriorSubq->addrFillSub);
+      }
+      sqlite3VdbeAddOp2(v, OP_OpenDup, pItem->iCursor, pPrior->iCursor);
+      pSub->nSelectRow = pPriorSubq->pSelect->nSelectRow;
+    }else{
+      /* Materialize the view.  If the view is not correlated, generate a
+      ** subroutine to do the materialization so that subsequent uses of
+      ** the same view can reuse the materialization.  tag-select-0488 */
+      int topAddr;
+      int onceAddr = 0;
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+      int addrExplain;
+#endif
+
+      pSubq->regReturn = ++pParse->nMem;
+      topAddr = sqlite3VdbeAddOp0(v, OP_Goto);
+      pSubq->addrFillSub = topAddr+1;
+      pItem->fg.isMaterialized = 1;
+      if( pItem->fg.isCorrelated==0 ){
+        /* If the subquery is not correlated and if we are not inside of
+        ** a trigger, then we only need to compute the value of the subquery
+        ** once. */
+        onceAddr = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+        VdbeComment((v, "materialize %!S", pItem));
+      }else{
+        VdbeNoopComment((v, "materialize %!S", pItem));
+      }
+      sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
+
+      ExplainQueryPlan2(addrExplain, (pParse, 1, "MATERIALIZE %!S", pItem));
+      sqlite3Select(pParse, pSub, &dest);
+      pItem->pSTab->nRowLogEst = pSub->nSelectRow;
+      if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
+      sqlite3VdbeAddOp2(v, OP_Return, pSubq->regReturn, topAddr+1);
+      VdbeComment((v, "end %!S", pItem));
+      sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1);
+      sqlite3VdbeJumpHere(v, topAddr);
+      sqlite3ClearTempRegCache(pParse);
+      if( pItem->fg.isCte && pItem->fg.isCorrelated==0 ){
+        CteUse *pCteUse = pItem->u2.pCteUse;
+        pCteUse->addrM9e = pSubq->addrFillSub;
+        pCteUse->regRtn = pSubq->regReturn;
+        pCteUse->iCur = pItem->iCursor;
+        pCteUse->nRowEst = pSub->nSelectRow;
+      }
+    }
+    if( db->mallocFailed ) goto select_end;
+    pParse->nHeight -= sqlite3SelectExprHeight(p);
+    pParse->zAuthContext = zSavedAuthContext;
+#endif
+  }
+
+  /* Various elements of the SELECT copied into local variables for
+  ** convenience */
+  pEList = p->pEList;
+  pWhere = p->pWhere;
+  pGroupBy = p->pGroupBy;
+  pHaving = p->pHaving;
+  sDistinct.isTnct = (p->selFlags & SF_Distinct)!=0;
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x8000 ){
+    TREETRACE(0x8000,pParse,p,("After all FROM-clause analysis:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+
+  /* tag-select-0500
+  **
+  ** If the query is DISTINCT with an ORDER BY but is not an aggregate, and
+  ** if the select-list is the same as the ORDER BY list, then this query
+  ** can be rewritten as a GROUP BY. In other words, this:
+  **
+  **     SELECT DISTINCT xyz FROM ... ORDER BY xyz
+  **
+  ** is transformed to:
+  **
+  **     SELECT xyz FROM ... GROUP BY xyz ORDER BY xyz
+  **
+  ** The second form is preferred as a single index (or temp-table) may be
+  ** used for both the ORDER BY and DISTINCT processing. As originally
+  ** written the query must use a temp-table for at least one of the ORDER
+  ** BY and DISTINCT, and an index or separate temp-table for the other.
+  */
+  if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct
+   && sqlite3ExprListCompare(sSort.pOrderBy, pEList, -1)==0
+   && OptimizationEnabled(db, SQLITE_GroupByOrder)
+#ifndef SQLITE_OMIT_WINDOWFUNC
+   && p->pWin==0
+#endif
+  ){
+    p->selFlags &= ~SF_Distinct;
+    pGroupBy = p->pGroupBy = sqlite3ExprListDup(db, pEList, 0);
+    if( pGroupBy ){
+      for(i=0; i<pGroupBy->nExpr; i++){
+        pGroupBy->a[i].u.x.iOrderByCol = i+1;
+      }
+    }
+    p->selFlags |= SF_Aggregate;
+    /* Notice that even thought SF_Distinct has been cleared from p->selFlags,
+    ** the sDistinct.isTnct is still set.  Hence, isTnct represents the
+    ** original setting of the SF_Distinct flag, not the current setting */
+    assert( sDistinct.isTnct );
+    sDistinct.isTnct = 2;
+
+#if TREETRACE_ENABLED
+    if( sqlite3TreeTrace & 0x20000 ){
+      TREETRACE(0x20000,pParse,p,("Transform DISTINCT into GROUP BY:\n"));
+      sqlite3TreeViewSelect(0, p, 0);
+    }
+#endif
+  }
+
+  /* If there is an ORDER BY clause, then create an ephemeral index to
+  ** do the sorting.  But this sorting ephemeral index might end up
+  ** being unused if the data can be extracted in pre-sorted order.
+  ** If that is the case, then the OP_OpenEphemeral instruction will be
+  ** changed to an OP_Noop once we figure out that the sorting index is
+  ** not needed.  The sSort.addrSortIndex variable is used to facilitate
+  ** that change.  tag-select-0600
+  */
+  if( sSort.pOrderBy ){
+    KeyInfo *pKeyInfo;
+    pKeyInfo = sqlite3KeyInfoFromExprList(
+        pParse, sSort.pOrderBy, 0, pEList->nExpr);
+    sSort.iECursor = pParse->nTab++;
+    sSort.addrSortIndex =
+      sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+          sSort.iECursor, sSort.pOrderBy->nExpr+1+pEList->nExpr, 0,
+          (char*)pKeyInfo, P4_KEYINFO
+      );
+  }else{
+    sSort.addrSortIndex = -1;
+  }
+
+  /* If the output is destined for a temporary table, open that table.
+  ** tag-select-0630
+  */
+  if( pDest->eDest==SRT_EphemTab ){
+    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iSDParm, pEList->nExpr);
+    if( p->selFlags & SF_NestedFrom ){
+      /* Delete or NULL-out result columns that will never be used */
+      int ii;
+      for(ii=pEList->nExpr-1; ii>0 && pEList->a[ii].fg.bUsed==0; ii--){
+        sqlite3ExprDelete(db, pEList->a[ii].pExpr);
+        sqlite3DbFree(db, pEList->a[ii].zEName);
+        pEList->nExpr--;
+      }
+      for(ii=0; ii<pEList->nExpr; ii++){
+        if( pEList->a[ii].fg.bUsed==0 ) pEList->a[ii].pExpr->op = TK_NULL;
+      }
+    }
+  }
+
+  /* Set the limiter.  tag-select-0650
+  */
+  iEnd = sqlite3VdbeMakeLabel(pParse);
+  if( (p->selFlags & SF_FixedLimit)==0 ){
+    p->nSelectRow = 320;  /* 4 billion rows */
+  }
+  if( p->pLimit ) computeLimitRegisters(pParse, p, iEnd);
+  if( p->iLimit==0 && sSort.addrSortIndex>=0 ){
+    sqlite3VdbeChangeOpcode(v, sSort.addrSortIndex, OP_SorterOpen);
+    sSort.sortFlags |= SORTFLAG_UseSorter;
+  }
+
+  /* Open an ephemeral index to use for the distinct set. tag-select-0680
+  */
+  if( p->selFlags & SF_Distinct ){
+    sDistinct.tabTnct = pParse->nTab++;
+    sDistinct.addrTnct = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+                       sDistinct.tabTnct, 0, 0,
+                       (char*)sqlite3KeyInfoFromExprList(pParse, p->pEList,0,0),
+                       P4_KEYINFO);
+    sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
+    sDistinct.eTnctType = WHERE_DISTINCT_UNORDERED;
+  }else{
+    sDistinct.eTnctType = WHERE_DISTINCT_NOOP;
+  }
+
+  if( !isAgg && pGroupBy==0 ){
+    /* No aggregate functions and no GROUP BY clause.  tag-select-0700 */
+    u16 wctrlFlags = (sDistinct.isTnct ? WHERE_WANT_DISTINCT : 0)
+                   | (p->selFlags & SF_FixedLimit);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    Window *pWin = p->pWin;      /* Main window object (or NULL) */
+    if( pWin ){
+      sqlite3WindowCodeInit(pParse, p);
+    }
+#endif
+    assert( WHERE_USE_LIMIT==SF_FixedLimit );
+
+
+    /* Begin the database scan. */
+    TREETRACE(0x2,pParse,p,("WhereBegin\n"));
+    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, sSort.pOrderBy,
+                               p->pEList, p, wctrlFlags, p->nSelectRow);
+    if( pWInfo==0 ) goto select_end;
+    if( sqlite3WhereOutputRowCount(pWInfo) < p->nSelectRow ){
+      p->nSelectRow = sqlite3WhereOutputRowCount(pWInfo);
+    }
+    if( sDistinct.isTnct && sqlite3WhereIsDistinct(pWInfo) ){
+      sDistinct.eTnctType = sqlite3WhereIsDistinct(pWInfo);
+    }
+    if( sSort.pOrderBy ){
+      sSort.nOBSat = sqlite3WhereIsOrdered(pWInfo);
+      sSort.labelOBLopt = sqlite3WhereOrderByLimitOptLabel(pWInfo);
+      if( sSort.nOBSat==sSort.pOrderBy->nExpr ){
+        sSort.pOrderBy = 0;
+      }
+    }
+    TREETRACE(0x2,pParse,p,("WhereBegin returns\n"));
+
+    /* If sorting index that was created by a prior OP_OpenEphemeral
+    ** instruction ended up not being needed, then change the OP_OpenEphemeral
+    ** into an OP_Noop.
+    */
+    if( sSort.addrSortIndex>=0 && sSort.pOrderBy==0 ){
+      sqlite3VdbeChangeToNoop(v, sSort.addrSortIndex);
+    }
+
+    assert( p->pEList==pEList );
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( pWin ){
+      int addrGosub = sqlite3VdbeMakeLabel(pParse);
+      int iCont = sqlite3VdbeMakeLabel(pParse);
+      int iBreak = sqlite3VdbeMakeLabel(pParse);
+      int regGosub = ++pParse->nMem;
+
+      sqlite3WindowCodeStep(pParse, p, pWInfo, regGosub, addrGosub);
+
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, iBreak);
+      sqlite3VdbeResolveLabel(v, addrGosub);
+      VdbeNoopComment((v, "inner-loop subroutine"));
+      sSort.labelOBLopt = 0;
+      selectInnerLoop(pParse, p, -1, &sSort, &sDistinct, pDest, iCont, iBreak);
+      sqlite3VdbeResolveLabel(v, iCont);
+      sqlite3VdbeAddOp1(v, OP_Return, regGosub);
+      VdbeComment((v, "end inner-loop subroutine"));
+      sqlite3VdbeResolveLabel(v, iBreak);
+    }else
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+    {
+      /* Use the standard inner loop. */
+      selectInnerLoop(pParse, p, -1, &sSort, &sDistinct, pDest,
+          sqlite3WhereContinueLabel(pWInfo),
+          sqlite3WhereBreakLabel(pWInfo));
+
+      /* End the database scan loop.
+      */
+      TREETRACE(0x2,pParse,p,("WhereEnd\n"));
+      sqlite3WhereEnd(pWInfo);
+    }
+  }else{
+    /* This case is for when there exist aggregate functions or a GROUP BY
+    ** clause or both.  tag-select-0800 */
+    NameContext sNC;    /* Name context for processing aggregate information */
+    int iAMem;          /* First Mem address for storing current GROUP BY */
+    int iBMem;          /* First Mem address for previous GROUP BY */
+    int iUseFlag;       /* Mem address holding flag indicating that at least
+                        ** one row of the input to the aggregator has been
+                        ** processed */
+    int iAbortFlag;     /* Mem address which causes query abort if positive */
+    int groupBySort;    /* Rows come from source in GROUP BY order */
+    int addrEnd;        /* End of processing for this SELECT */
+    int sortPTab = 0;   /* Pseudotable used to decode sorting results */
+    int sortOut = 0;    /* Output register from the sorter */
+    int orderByGrp = 0; /* True if the GROUP BY and ORDER BY are the same */
+
+    /* Remove any and all aliases between the result set and the
+    ** GROUP BY clause.
+    */
+    if( pGroupBy ){
+      int k;                        /* Loop counter */
+      struct ExprList_item *pItem;  /* For looping over expression in a list */
+
+      for(k=p->pEList->nExpr, pItem=p->pEList->a; k>0; k--, pItem++){
+        pItem->u.x.iAlias = 0;
+      }
+      for(k=pGroupBy->nExpr, pItem=pGroupBy->a; k>0; k--, pItem++){
+        pItem->u.x.iAlias = 0;
+      }
+      assert( 66==sqlite3LogEst(100) );
+      if( p->nSelectRow>66 ) p->nSelectRow = 66;
+
+      /* If there is both a GROUP BY and an ORDER BY clause and they are
+      ** identical, then it may be possible to disable the ORDER BY clause
+      ** on the grounds that the GROUP BY will cause elements to come out
+      ** in the correct order. It also may not - the GROUP BY might use a
+      ** database index that causes rows to be grouped together as required
+      ** but not actually sorted. Either way, record the fact that the
+      ** ORDER BY and GROUP BY clauses are the same by setting the orderByGrp
+      ** variable.  */
+      if( sSort.pOrderBy && pGroupBy->nExpr==sSort.pOrderBy->nExpr ){
+        int ii;
+        /* The GROUP BY processing doesn't care whether rows are delivered in
+        ** ASC or DESC order - only that each group is returned contiguously.
+        ** So set the ASC/DESC flags in the GROUP BY to match those in the
+        ** ORDER BY to maximize the chances of rows being delivered in an
+        ** order that makes the ORDER BY redundant.  */
+        for(ii=0; ii<pGroupBy->nExpr; ii++){
+          u8 sortFlags;
+          sortFlags = sSort.pOrderBy->a[ii].fg.sortFlags & KEYINFO_ORDER_DESC;
+          pGroupBy->a[ii].fg.sortFlags = sortFlags;
+        }
+        if( sqlite3ExprListCompare(pGroupBy, sSort.pOrderBy, -1)==0 ){
+          orderByGrp = 1;
+        }
+      }
+    }else{
+      assert( 0==sqlite3LogEst(1) );
+      p->nSelectRow = 0;
+    }
+
+    /* Create a label to jump to when we want to abort the query */
+    addrEnd = sqlite3VdbeMakeLabel(pParse);
+
+    /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
+    ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
+    ** SELECT statement.
+    */
+    pAggInfo = sqlite3DbMallocZero(db, sizeof(*pAggInfo) );
+    if( pAggInfo ){
+      sqlite3ParserAddCleanup(pParse, agginfoFree, pAggInfo);
+      testcase( pParse->earlyCleanup );
+    }
+    if( db->mallocFailed ){
+      goto select_end;
+    }
+    pAggInfo->selId = p->selId;
+#ifdef SQLITE_DEBUG
+    pAggInfo->pSelect = p;
+#endif
+    memset(&sNC, 0, sizeof(sNC));
+    sNC.pParse = pParse;
+    sNC.pSrcList = pTabList;
+    sNC.uNC.pAggInfo = pAggInfo;
+    VVA_ONLY( sNC.ncFlags = NC_UAggInfo; )
+    pAggInfo->nSortingColumn = pGroupBy ? pGroupBy->nExpr : 0;
+    pAggInfo->pGroupBy = pGroupBy;
+    sqlite3ExprAnalyzeAggList(&sNC, pEList);
+    sqlite3ExprAnalyzeAggList(&sNC, sSort.pOrderBy);
+    if( pHaving ){
+      if( pGroupBy ){
+        assert( pWhere==p->pWhere );
+        assert( pHaving==p->pHaving );
+        assert( pGroupBy==p->pGroupBy );
+        havingToWhere(pParse, p);
+        pWhere = p->pWhere;
+      }
+      sqlite3ExprAnalyzeAggregates(&sNC, pHaving);
+    }
+    pAggInfo->nAccumulator = pAggInfo->nColumn;
+    if( p->pGroupBy==0 && p->pHaving==0 && pAggInfo->nFunc==1 ){
+      minMaxFlag = minMaxQuery(db, pAggInfo->aFunc[0].pFExpr, &pMinMaxOrderBy);
+    }else{
+      minMaxFlag = WHERE_ORDERBY_NORMAL;
+    }
+    analyzeAggFuncArgs(pAggInfo, &sNC);
+    if( db->mallocFailed ) goto select_end;
+#if TREETRACE_ENABLED
+    if( sqlite3TreeTrace & 0x20 ){
+      TREETRACE(0x20,pParse,p,("After aggregate analysis %p:\n", pAggInfo));
+      sqlite3TreeViewSelect(0, p, 0);
+      if( minMaxFlag ){
+        sqlite3DebugPrintf("MIN/MAX Optimization (0x%02x) adds:\n", minMaxFlag);
+        sqlite3TreeViewExprList(0, pMinMaxOrderBy, 0, "ORDERBY");
+      }
+      printAggInfo(pAggInfo);
+    }
+#endif
+
+
+    /* Processing for aggregates with GROUP BY is very different and
+    ** much more complex than aggregates without a GROUP BY.  tag-select-0810
+    */
+    if( pGroupBy ){
+      KeyInfo *pKeyInfo;  /* Keying information for the group by clause */
+      int addr1;          /* A-vs-B comparison jump */
+      int addrOutputRow;  /* Start of subroutine that outputs a result row */
+      int regOutputRow;   /* Return address register for output subroutine */
+      int addrSetAbort;   /* Set the abort flag and return */
+      int addrTopOfLoop;  /* Top of the input loop */
+      int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
+      int addrReset;      /* Subroutine for resetting the accumulator */
+      int regReset;       /* Return address register for reset subroutine */
+      ExprList *pDistinct = 0;
+      u16 distFlag = 0;
+      int eDist = WHERE_DISTINCT_NOOP;
+
+      if( pAggInfo->nFunc==1
+       && pAggInfo->aFunc[0].iDistinct>=0
+       && ALWAYS(pAggInfo->aFunc[0].pFExpr!=0)
+       && ALWAYS(ExprUseXList(pAggInfo->aFunc[0].pFExpr))
+       && pAggInfo->aFunc[0].pFExpr->x.pList!=0
+      ){
+        Expr *pExpr = pAggInfo->aFunc[0].pFExpr->x.pList->a[0].pExpr;
+        pExpr = sqlite3ExprDup(db, pExpr, 0);
+        pDistinct = sqlite3ExprListDup(db, pGroupBy, 0);
+        pDistinct = sqlite3ExprListAppend(pParse, pDistinct, pExpr);
+        distFlag = pDistinct ? (WHERE_WANT_DISTINCT|WHERE_AGG_DISTINCT) : 0;
+      }
+
+      /* If there is a GROUP BY clause we might need a sorting index to
+      ** implement it.  Allocate that sorting index now.  If it turns out
+      ** that we do not need it after all, the OP_SorterOpen instruction
+      ** will be converted into a Noop.
+      */
+      pAggInfo->sortingIdx = pParse->nTab++;
+      pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pGroupBy,
+                                            0, pAggInfo->nColumn);
+      addrSortingIdx = sqlite3VdbeAddOp4(v, OP_SorterOpen,
+          pAggInfo->sortingIdx, pAggInfo->nSortingColumn,
+          0, (char*)pKeyInfo, P4_KEYINFO);
+
+      /* Initialize memory locations used by GROUP BY aggregate processing
+      */
+      iUseFlag = ++pParse->nMem;
+      iAbortFlag = ++pParse->nMem;
+      regOutputRow = ++pParse->nMem;
+      addrOutputRow = sqlite3VdbeMakeLabel(pParse);
+      regReset = ++pParse->nMem;
+      addrReset = sqlite3VdbeMakeLabel(pParse);
+      iAMem = pParse->nMem + 1;
+      pParse->nMem += pGroupBy->nExpr;
+      iBMem = pParse->nMem + 1;
+      pParse->nMem += pGroupBy->nExpr;
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, iAbortFlag);
+      VdbeComment((v, "clear abort flag"));
+      sqlite3VdbeAddOp3(v, OP_Null, 0, iAMem, iAMem+pGroupBy->nExpr-1);
+
+      /* Begin a loop that will extract all source rows in GROUP BY order.
+      ** This might involve two separate loops with an OP_Sort in between, or
+      ** it might be a single loop that uses an index to extract information
+      ** in the right order to begin with.
+      */
+      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
+      TREETRACE(0x2,pParse,p,("WhereBegin\n"));
+      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pGroupBy, pDistinct,
+          p, (sDistinct.isTnct==2 ? WHERE_DISTINCTBY : WHERE_GROUPBY)
+          |  (orderByGrp ? WHERE_SORTBYGROUP : 0) | distFlag, 0
+      );
+      if( pWInfo==0 ){
+        sqlite3ExprListDelete(db, pDistinct);
+        goto select_end;
+      }
+      if( pParse->pIdxEpr ){
+        optimizeAggregateUseOfIndexedExpr(pParse, p, pAggInfo, &sNC);
+      }
+      assignAggregateRegisters(pParse, pAggInfo);
+      eDist = sqlite3WhereIsDistinct(pWInfo);
+      TREETRACE(0x2,pParse,p,("WhereBegin returns\n"));
+      if( sqlite3WhereIsOrdered(pWInfo)==pGroupBy->nExpr ){
+        /* The optimizer is able to deliver rows in group by order so
+        ** we do not have to sort.  The OP_OpenEphemeral table will be
+        ** cancelled later because we still need to use the pKeyInfo
+        */
+        groupBySort = 0;
+      }else{
+        /* Rows are coming out in undetermined order.  We have to push
+        ** each row into a sorting index, terminate the first loop,
+        ** then loop over the sorting index in order to get the output
+        ** in sorted order
+        */
+        int regBase;
+        int regRecord;
+        int nCol;
+        int nGroupBy;
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+        int addrExp;              /* Address of OP_Explain instruction */
+#endif
+        ExplainQueryPlan2(addrExp, (pParse, 0, "USE TEMP B-TREE FOR %s",
+            (sDistinct.isTnct && (p->selFlags&SF_Distinct)==0) ?
+                    "DISTINCT" : "GROUP BY"
+        ));
+
+        groupBySort = 1;
+        nGroupBy = pGroupBy->nExpr;
+        nCol = nGroupBy;
+        j = nGroupBy;
+        for(i=0; i<pAggInfo->nColumn; i++){
+          if( pAggInfo->aCol[i].iSorterColumn>=j ){
+            nCol++;
+            j++;
+          }
+        }
+        regBase = sqlite3GetTempRange(pParse, nCol);
+        sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0, 0);
+        j = nGroupBy;
+        pAggInfo->directMode = 1;
+        for(i=0; i<pAggInfo->nColumn; i++){
+          struct AggInfo_col *pCol = &pAggInfo->aCol[i];
+          if( pCol->iSorterColumn>=j ){
+            sqlite3ExprCode(pParse, pCol->pCExpr, j + regBase);
+            j++;
+          }
+        }
+        pAggInfo->directMode = 0;
+        regRecord = sqlite3GetTempReg(pParse);
+        sqlite3VdbeScanStatusCounters(v, addrExp, 0, sqlite3VdbeCurrentAddr(v));
+        sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord);
+        sqlite3VdbeAddOp2(v, OP_SorterInsert, pAggInfo->sortingIdx, regRecord);
+        sqlite3VdbeScanStatusRange(v, addrExp, sqlite3VdbeCurrentAddr(v)-2, -1);
+        sqlite3ReleaseTempReg(pParse, regRecord);
+        sqlite3ReleaseTempRange(pParse, regBase, nCol);
+        TREETRACE(0x2,pParse,p,("WhereEnd\n"));
+        sqlite3WhereEnd(pWInfo);
+        pAggInfo->sortingIdxPTab = sortPTab = pParse->nTab++;
+        sortOut = sqlite3GetTempReg(pParse);
+        sqlite3VdbeScanStatusCounters(v, addrExp, sqlite3VdbeCurrentAddr(v), 0);
+        sqlite3VdbeAddOp3(v, OP_OpenPseudo, sortPTab, sortOut, nCol);
+        sqlite3VdbeAddOp2(v, OP_SorterSort, pAggInfo->sortingIdx, addrEnd);
+        VdbeComment((v, "GROUP BY sort")); VdbeCoverage(v);
+        pAggInfo->useSortingIdx = 1;
+        sqlite3VdbeScanStatusRange(v, addrExp, -1, sortPTab);
+        sqlite3VdbeScanStatusRange(v, addrExp, -1, pAggInfo->sortingIdx);
+      }
+
+      /* If there are entries in pAgggInfo->aFunc[] that contain subexpressions
+      ** that are indexed (and that were previously identified and tagged
+      ** in optimizeAggregateUseOfIndexedExpr()) then those subexpressions
+      ** must now be converted into a TK_AGG_COLUMN node so that the value
+      ** is correctly pulled from the index rather than being recomputed. */
+      if( pParse->pIdxEpr ){
+        aggregateConvertIndexedExprRefToColumn(pAggInfo);
+#if TREETRACE_ENABLED
+        if( sqlite3TreeTrace & 0x20 ){
+          TREETRACE(0x20, pParse, p,
+             ("AggInfo function expressions converted to reference index\n"));
+          sqlite3TreeViewSelect(0, p, 0);
+          printAggInfo(pAggInfo);
+        }
+#endif
+      }
+
+      /* If the index or temporary table used by the GROUP BY sort
+      ** will naturally deliver rows in the order required by the ORDER BY
+      ** clause, cancel the ephemeral table open coded earlier.
+      **
+      ** This is an optimization - the correct answer should result regardless.
+      ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER to
+      ** disable this optimization for testing purposes.  */
+      if( orderByGrp && OptimizationEnabled(db, SQLITE_GroupByOrder)
+       && (groupBySort || sqlite3WhereIsSorted(pWInfo))
+      ){
+        sSort.pOrderBy = 0;
+        sqlite3VdbeChangeToNoop(v, sSort.addrSortIndex);
+      }
+
+      /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
+      ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
+      ** Then compare the current GROUP BY terms against the GROUP BY terms
+      ** from the previous row currently stored in a0, a1, a2...
+      */
+      addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
+      if( groupBySort ){
+        sqlite3VdbeAddOp3(v, OP_SorterData, pAggInfo->sortingIdx,
+                          sortOut, sortPTab);
+      }
+      for(j=0; j<pGroupBy->nExpr; j++){
+        int iOrderByCol = pGroupBy->a[j].u.x.iOrderByCol;
+
+        if( groupBySort ){
+          sqlite3VdbeAddOp3(v, OP_Column, sortPTab, j, iBMem+j);
+        }else{
+          pAggInfo->directMode = 1;
+          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
+        }
+
+        if( iOrderByCol ){
+          Expr *pX = p->pEList->a[iOrderByCol-1].pExpr;
+          Expr *pBase = sqlite3ExprSkipCollateAndLikely(pX);
+          if( ALWAYS(pBase!=0)
+           && pBase->op!=TK_AGG_COLUMN
+           && pBase->op!=TK_REGISTER
+          ){
+            sqlite3ExprToRegister(pX, iAMem+j);
+          }
+        }
+      }
+      sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr,
+                          (char*)sqlite3KeyInfoRef(pKeyInfo), P4_KEYINFO);
+      addr1 = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp3(v, OP_Jump, addr1+1, 0, addr1+1); VdbeCoverage(v);
+
+      /* Generate code that runs whenever the GROUP BY changes.
+      ** Changes in the GROUP BY are detected by the previous code
+      ** block.  If there were no changes, this block is skipped.
+      **
+      ** This code copies current group by terms in b0,b1,b2,...
+      ** over to a0,a1,a2.  It then calls the output subroutine
+      ** and resets the aggregate accumulator registers in preparation
+      ** for the next GROUP BY batch.
+      */
+      sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
+      VdbeComment((v, "output one row"));
+      sqlite3ExprCodeMove(pParse, iBMem, iAMem, pGroupBy->nExpr);
+      sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd); VdbeCoverage(v);
+      VdbeComment((v, "check abort flag"));
+      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
+      VdbeComment((v, "reset accumulator"));
+
+      /* Update the aggregate accumulators based on the content of
+      ** the current row
+      */
+      sqlite3VdbeJumpHere(v, addr1);
+      updateAccumulator(pParse, iUseFlag, pAggInfo, eDist);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag);
+      VdbeComment((v, "indicate data in accumulator"));
+
+      /* End of the loop
+      */
+      if( groupBySort ){
+        sqlite3VdbeAddOp2(v, OP_SorterNext, pAggInfo->sortingIdx,addrTopOfLoop);
+        VdbeCoverage(v);
+      }else{
+        TREETRACE(0x2,pParse,p,("WhereEnd\n"));
+        sqlite3WhereEnd(pWInfo);
+        sqlite3VdbeChangeToNoop(v, addrSortingIdx);
+      }
+      sqlite3ExprListDelete(db, pDistinct);
+
+      /* Output the final row of result
+      */
+      sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
+      VdbeComment((v, "output final row"));
+
+      /* Jump over the subroutines
+      */
+      sqlite3VdbeGoto(v, addrEnd);
+
+      /* Generate a subroutine that outputs a single row of the result
+      ** set.  This subroutine first looks at the iUseFlag.  If iUseFlag
+      ** is less than or equal to zero, the subroutine is a no-op.  If
+      ** the processing calls for the query to abort, this subroutine
+      ** increments the iAbortFlag memory location before returning in
+      ** order to signal the caller to abort.
+      */
+      addrSetAbort = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iAbortFlag);
+      VdbeComment((v, "set abort flag"));
+      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
+      sqlite3VdbeResolveLabel(v, addrOutputRow);
+      addrOutputRow = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2);
+      VdbeCoverage(v);
+      VdbeComment((v, "Groupby result generator entry point"));
+      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
+      finalizeAggFunctions(pParse, pAggInfo);
+      sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
+      selectInnerLoop(pParse, p, -1, &sSort,
+                      &sDistinct, pDest,
+                      addrOutputRow+1, addrSetAbort);
+      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
+      VdbeComment((v, "end groupby result generator"));
+
+      /* Generate a subroutine that will reset the group-by accumulator
+      */
+      sqlite3VdbeResolveLabel(v, addrReset);
+      resetAccumulator(pParse, pAggInfo);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
+      VdbeComment((v, "indicate accumulator empty"));
+      sqlite3VdbeAddOp1(v, OP_Return, regReset);
+
+      if( distFlag!=0 && eDist!=WHERE_DISTINCT_NOOP ){
+        struct AggInfo_func *pF = &pAggInfo->aFunc[0];
+        fixDistinctOpenEph(pParse, eDist, pF->iDistinct, pF->iDistAddr);
+      }
+    } /* endif pGroupBy.  Begin aggregate queries without GROUP BY: */
+    else {
+      /* Aggregate functions without GROUP BY. tag-select-0820 */
+      Table *pTab;
+      if( (pTab = isSimpleCount(p, pAggInfo))!=0 ){
+        /* tag-select-0821
+        **
+        ** If isSimpleCount() returns a pointer to a Table structure, then
+        ** the SQL statement is of the form:
+        **
+        **   SELECT count(*) FROM <tbl>
+        **
+        ** where the Table structure returned represents table <tbl>.
+        **
+        ** This statement is so common that it is optimized specially. The
+        ** OP_Count instruction is executed either on the intkey table that
+        ** contains the data for table <tbl> or on one of its indexes. It
+        ** is better to execute the op on an index, as indexes are almost
+        ** always spread across less pages than their corresponding tables.
+        */
+        const int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+        const int iCsr = pParse->nTab++;     /* Cursor to scan b-tree */
+        Index *pIdx;                         /* Iterator variable */
+        KeyInfo *pKeyInfo = 0;               /* Keyinfo for scanned index */
+        Index *pBest = 0;                    /* Best index found so far */
+        Pgno iRoot = pTab->tnum;             /* Root page of scanned b-tree */
+
+        sqlite3CodeVerifySchema(pParse, iDb);
+        sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+
+        /* Search for the index that has the lowest scan cost.
+        **
+        ** (2011-04-15) Do not do a full scan of an unordered index.
+        **
+        ** (2013-10-03) Do not count the entries in a partial index.
+        **
+        ** In practice the KeyInfo structure will not be used. It is only
+        ** passed to keep OP_OpenRead happy.
+        */
+        if( !HasRowid(pTab) ) pBest = sqlite3PrimaryKeyIndex(pTab);
+        if( !p->pSrc->a[0].fg.notIndexed ){
+          for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+            if( pIdx->bUnordered==0
+             && pIdx->szIdxRow<pTab->szTabRow
+             && pIdx->pPartIdxWhere==0
+             && (!pBest || pIdx->szIdxRow<pBest->szIdxRow)
+            ){
+              pBest = pIdx;
+            }
+          }
+        }
+        if( pBest ){
+          iRoot = pBest->tnum;
+          pKeyInfo = sqlite3KeyInfoOfIndex(pParse, pBest);
+        }
+
+        /* Open a read-only cursor, execute the OP_Count, close the cursor. */
+        sqlite3VdbeAddOp4Int(v, OP_OpenRead, iCsr, (int)iRoot, iDb, 1);
+        if( pKeyInfo ){
+          sqlite3VdbeChangeP4(v, -1, (char *)pKeyInfo, P4_KEYINFO);
+        }
+        assignAggregateRegisters(pParse, pAggInfo);
+        sqlite3VdbeAddOp2(v, OP_Count, iCsr, AggInfoFuncReg(pAggInfo,0));
+        sqlite3VdbeAddOp1(v, OP_Close, iCsr);
+        explainSimpleCount(pParse, pTab, pBest);
+      }else{
+        /* The general case of an aggregate query without GROUP BY
+        ** tag-select-0822 */
+        int regAcc = 0;           /* "populate accumulators" flag */
+        ExprList *pDistinct = 0;
+        u16 distFlag = 0;
+        int eDist;
+
+        /* If there are accumulator registers but no min() or max() functions
+        ** without FILTER clauses, allocate register regAcc. Register regAcc
+        ** will contain 0 the first time the inner loop runs, and 1 thereafter.
+        ** The code generated by updateAccumulator() uses this to ensure
+        ** that the accumulator registers are (a) updated only once if
+        ** there are no min() or max functions or (b) always updated for the
+        ** first row visited by the aggregate, so that they are updated at
+        ** least once even if the FILTER clause means the min() or max()
+        ** function visits zero rows.  */
+        if( pAggInfo->nAccumulator ){
+          for(i=0; i<pAggInfo->nFunc; i++){
+            if( ExprHasProperty(pAggInfo->aFunc[i].pFExpr, EP_WinFunc) ){
+              continue;
+            }
+            if( pAggInfo->aFunc[i].pFunc->funcFlags&SQLITE_FUNC_NEEDCOLL ){
+              break;
+            }
+          }
+          if( i==pAggInfo->nFunc ){
+            regAcc = ++pParse->nMem;
+            sqlite3VdbeAddOp2(v, OP_Integer, 0, regAcc);
+          }
+        }else if( pAggInfo->nFunc==1 && pAggInfo->aFunc[0].iDistinct>=0 ){
+          assert( ExprUseXList(pAggInfo->aFunc[0].pFExpr) );
+          pDistinct = pAggInfo->aFunc[0].pFExpr->x.pList;
+          distFlag = pDistinct ? (WHERE_WANT_DISTINCT|WHERE_AGG_DISTINCT) : 0;
+        }
+        assignAggregateRegisters(pParse, pAggInfo);
+
+        /* This case runs if the aggregate has no GROUP BY clause.  The
+        ** processing is much simpler since there is only a single row
+        ** of output.
+        */
+        assert( p->pGroupBy==0 );
+        resetAccumulator(pParse, pAggInfo);
+
+        /* If this query is a candidate for the min/max optimization, then
+        ** minMaxFlag will have been previously set to either
+        ** WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX and pMinMaxOrderBy will
+        ** be an appropriate ORDER BY expression for the optimization.
+        */
+        assert( minMaxFlag==WHERE_ORDERBY_NORMAL || pMinMaxOrderBy!=0 );
+        assert( pMinMaxOrderBy==0 || pMinMaxOrderBy->nExpr==1 );
+
+        TREETRACE(0x2,pParse,p,("WhereBegin\n"));
+        pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pMinMaxOrderBy,
+                                   pDistinct, p, minMaxFlag|distFlag, 0);
+        if( pWInfo==0 ){
+          goto select_end;
+        }
+        TREETRACE(0x2,pParse,p,("WhereBegin returns\n"));
+        eDist = sqlite3WhereIsDistinct(pWInfo);
+        updateAccumulator(pParse, regAcc, pAggInfo, eDist);
+        if( eDist!=WHERE_DISTINCT_NOOP ){
+          struct AggInfo_func *pF = pAggInfo->aFunc;
+          if( pF ){
+            fixDistinctOpenEph(pParse, eDist, pF->iDistinct, pF->iDistAddr);
+          }
+        }
+
+        if( regAcc ) sqlite3VdbeAddOp2(v, OP_Integer, 1, regAcc);
+        if( minMaxFlag ){
+          sqlite3WhereMinMaxOptEarlyOut(v, pWInfo);
+        }
+        TREETRACE(0x2,pParse,p,("WhereEnd\n"));
+        sqlite3WhereEnd(pWInfo);
+        finalizeAggFunctions(pParse, pAggInfo);
+      }
+
+      sSort.pOrderBy = 0;
+      sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
+      selectInnerLoop(pParse, p, -1, 0, 0,
+                      pDest, addrEnd, addrEnd);
+    }
+    sqlite3VdbeResolveLabel(v, addrEnd);
+
+  } /* endif aggregate query */
+
+  if( sDistinct.eTnctType==WHERE_DISTINCT_UNORDERED ){
+    explainTempTable(pParse, "DISTINCT");
+  }
+
+  /* If there is an ORDER BY clause, then we need to sort the results
+  ** and send them to the callback one by one.  tag-select-0900
+  */
+  if( sSort.pOrderBy ){
+    assert( p->pEList==pEList );
+    generateSortTail(pParse, p, &sSort, pEList->nExpr, pDest);
+  }
+
+  /* Jump here to skip this query
+  */
+  sqlite3VdbeResolveLabel(v, iEnd);
+
+  /* The SELECT has been coded. If there is an error in the Parse structure,
+  ** set the return code to 1. Otherwise 0. */
+  rc = (pParse->nErr>0);
+
+  /* Control jumps to here if an error is encountered above, or upon
+  ** successful coding of the SELECT.
+  */
+select_end:
+  assert( db->mallocFailed==0 || db->mallocFailed==1 );
+  assert( db->mallocFailed==0 || pParse->nErr!=0 );
+  sqlite3ExprListDelete(db, pMinMaxOrderBy);
+#ifdef SQLITE_DEBUG
+  /* Internal self-checks.  tag-select-1000 */
+  if( pAggInfo && !db->mallocFailed ){
+#if TREETRACE_ENABLED
+    if( sqlite3TreeTrace & 0x20 ){
+      TREETRACE(0x20,pParse,p,("Finished with AggInfo\n"));
+      printAggInfo(pAggInfo);
+    }
+#endif
+    for(i=0; i<pAggInfo->nColumn; i++){
+      Expr *pExpr = pAggInfo->aCol[i].pCExpr;
+      if( pExpr==0 ) continue;
+      assert( pExpr->pAggInfo==pAggInfo );
+      assert( pExpr->iAgg==i );
+    }
+    for(i=0; i<pAggInfo->nFunc; i++){
+      Expr *pExpr = pAggInfo->aFunc[i].pFExpr;
+      assert( pExpr!=0 );
+      assert( pExpr->pAggInfo==pAggInfo );
+      assert( pExpr->iAgg==i );
+    }
+  }
+#endif
+
+#if TREETRACE_ENABLED
+  TREETRACE(0x1,pParse,p,("end processing\n"));
+  if( (sqlite3TreeTrace & 0x40000)!=0 && ExplainQueryPlanParent(pParse)==0 ){
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+  ExplainQueryPlanPop(pParse);
+  return rc;
+}
+
+/************** End of select.c **********************************************/
+/************** Begin file table.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the sqlite3_get_table() and sqlite3_free_table()
+** interface routines.  These are just wrappers around the main
+** interface routine of sqlite3_exec().
+**
+** These routines are in a separate files so that they will not be linked
+** if they are not used.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_GET_TABLE
+
+/*
+** This structure is used to pass data from sqlite3_get_table() through
+** to the callback function is uses to build the result.
+*/
+typedef struct TabResult {
+  char **azResult;   /* Accumulated output */
+  char *zErrMsg;     /* Error message text, if an error occurs */
+  u32 nAlloc;        /* Slots allocated for azResult[] */
+  u32 nRow;          /* Number of rows in the result */
+  u32 nColumn;       /* Number of columns in the result */
+  u32 nData;         /* Slots used in azResult[].  (nRow+1)*nColumn */
+  int rc;            /* Return code from sqlite3_exec() */
+} TabResult;
+
+/*
+** This routine is called once for each row in the result table.  Its job
+** is to fill in the TabResult structure appropriately, allocating new
+** memory as necessary.
+*/
+static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){
+  TabResult *p = (TabResult*)pArg;  /* Result accumulator */
+  int need;                         /* Slots needed in p->azResult[] */
+  int i;                            /* Loop counter */
+  char *z;                          /* A single column of result */
+
+  /* Make sure there is enough space in p->azResult to hold everything
+  ** we need to remember from this invocation of the callback.
+  */
+  if( p->nRow==0 && argv!=0 ){
+    need = nCol*2;
+  }else{
+    need = nCol;
+  }
+  if( p->nData + need > p->nAlloc ){
+    char **azNew;
+    p->nAlloc = p->nAlloc*2 + need;
+    azNew = sqlite3Realloc( p->azResult, sizeof(char*)*p->nAlloc );
+    if( azNew==0 ) goto malloc_failed;
+    p->azResult = azNew;
+  }
+
+  /* If this is the first row, then generate an extra row containing
+  ** the names of all columns.
+  */
+  if( p->nRow==0 ){
+    p->nColumn = nCol;
+    for(i=0; i<nCol; i++){
+      z = sqlite3_mprintf("%s", colv[i]);
+      if( z==0 ) goto malloc_failed;
+      p->azResult[p->nData++] = z;
+    }
+  }else if( (int)p->nColumn!=nCol ){
+    sqlite3_free(p->zErrMsg);
+    p->zErrMsg = sqlite3_mprintf(
+       "sqlite3_get_table() called with two or more incompatible queries"
+    );
+    p->rc = SQLITE_ERROR;
+    return 1;
+  }
+
+  /* Copy over the row data
+  */
+  if( argv!=0 ){
+    for(i=0; i<nCol; i++){
+      if( argv[i]==0 ){
+        z = 0;
+      }else{
+        int n = sqlite3Strlen30(argv[i])+1;
+        z = sqlite3_malloc64( n );
+        if( z==0 ) goto malloc_failed;
+        memcpy(z, argv[i], n);
+      }
+      p->azResult[p->nData++] = z;
+    }
+    p->nRow++;
+  }
+  return 0;
+
+malloc_failed:
+  p->rc = SQLITE_NOMEM_BKPT;
+  return 1;
+}
+
+/*
+** Query the database.  But instead of invoking a callback for each row,
+** malloc() for space to hold the result and return the entire results
+** at the conclusion of the call.
+**
+** The result that is written to ***pazResult is held in memory obtained
+** from malloc().  But the caller cannot free this memory directly.
+** Instead, the entire table should be passed to sqlite3_free_table() when
+** the calling procedure is finished using it.
+*/
+SQLITE_API int sqlite3_get_table(
+  sqlite3 *db,                /* The database on which the SQL executes */
+  const char *zSql,           /* The SQL to be executed */
+  char ***pazResult,          /* Write the result table here */
+  int *pnRow,                 /* Write the number of rows in the result here */
+  int *pnColumn,              /* Write the number of columns of result here */
+  char **pzErrMsg             /* Write error messages here */
+){
+  int rc;
+  TabResult res;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || pazResult==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *pazResult = 0;
+  if( pnColumn ) *pnColumn = 0;
+  if( pnRow ) *pnRow = 0;
+  if( pzErrMsg ) *pzErrMsg = 0;
+  res.zErrMsg = 0;
+  res.nRow = 0;
+  res.nColumn = 0;
+  res.nData = 1;
+  res.nAlloc = 20;
+  res.rc = SQLITE_OK;
+  res.azResult = sqlite3_malloc64(sizeof(char*)*res.nAlloc );
+  if( res.azResult==0 ){
+     db->errCode = SQLITE_NOMEM;
+     return SQLITE_NOMEM_BKPT;
+  }
+  res.azResult[0] = 0;
+  rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg);
+  assert( sizeof(res.azResult[0])>= sizeof(res.nData) );
+  res.azResult[0] = SQLITE_INT_TO_PTR(res.nData);
+  if( (rc&0xff)==SQLITE_ABORT ){
+    sqlite3_free_table(&res.azResult[1]);
+    if( res.zErrMsg ){
+      if( pzErrMsg ){
+        sqlite3_free(*pzErrMsg);
+        *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg);
+      }
+      sqlite3_free(res.zErrMsg);
+    }
+    db->errCode = res.rc;  /* Assume 32-bit assignment is atomic */
+    return res.rc;
+  }
+  sqlite3_free(res.zErrMsg);
+  if( rc!=SQLITE_OK ){
+    sqlite3_free_table(&res.azResult[1]);
+    return rc;
+  }
+  if( res.nAlloc>res.nData ){
+    char **azNew;
+    azNew = sqlite3Realloc( res.azResult, sizeof(char*)*res.nData );
+    if( azNew==0 ){
+      sqlite3_free_table(&res.azResult[1]);
+      db->errCode = SQLITE_NOMEM;
+      return SQLITE_NOMEM_BKPT;
+    }
+    res.azResult = azNew;
+  }
+  *pazResult = &res.azResult[1];
+  if( pnColumn ) *pnColumn = res.nColumn;
+  if( pnRow ) *pnRow = res.nRow;
+  return rc;
+}
+
+/*
+** This routine frees the space the sqlite3_get_table() malloced.
+*/
+SQLITE_API void sqlite3_free_table(
+  char **azResult            /* Result returned from sqlite3_get_table() */
+){
+  if( azResult ){
+    int i, n;
+    azResult--;
+    assert( azResult!=0 );
+    n = SQLITE_PTR_TO_INT(azResult[0]);
+    for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); }
+    sqlite3_free(azResult);
+  }
+}
+
+#endif /* SQLITE_OMIT_GET_TABLE */
+
+/************** End of table.c ***********************************************/
+/************** Begin file trigger.c *****************************************/
+/*
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the implementation for TRIGGERs
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_TRIGGER
+/*
+** Delete a linked list of TriggerStep structures.
+*/
+SQLITE_PRIVATE void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerStep){
+  while( pTriggerStep ){
+    TriggerStep * pTmp = pTriggerStep;
+    pTriggerStep = pTriggerStep->pNext;
+
+    sqlite3ExprDelete(db, pTmp->pWhere);
+    sqlite3ExprListDelete(db, pTmp->pExprList);
+    sqlite3SelectDelete(db, pTmp->pSelect);
+    sqlite3IdListDelete(db, pTmp->pIdList);
+    sqlite3UpsertDelete(db, pTmp->pUpsert);
+    sqlite3SrcListDelete(db, pTmp->pFrom);
+    sqlite3DbFree(db, pTmp->zSpan);
+
+    sqlite3DbFree(db, pTmp);
+  }
+}
+
+/*
+** Given table pTab, return a list of all the triggers attached to
+** the table. The list is connected by Trigger.pNext pointers.
+**
+** All of the triggers on pTab that are in the same database as pTab
+** are already attached to pTab->pTrigger.  But there might be additional
+** triggers on pTab in the TEMP schema.  This routine prepends all
+** TEMP triggers on pTab to the beginning of the pTab->pTrigger list
+** and returns the combined list.
+**
+** To state it another way:  This routine returns a list of all triggers
+** that fire off of pTab.  The list will include any TEMP triggers on
+** pTab as well as the triggers lised in pTab->pTrigger.
+*/
+SQLITE_PRIVATE Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){
+  Schema *pTmpSchema;       /* Schema of the pTab table */
+  Trigger *pList;           /* List of triggers to return */
+  HashElem *p;              /* Loop variable for TEMP triggers */
+
+  assert( pParse->disableTriggers==0 );
+  pTmpSchema = pParse->db->aDb[1].pSchema;
+  p = sqliteHashFirst(&pTmpSchema->trigHash);
+  pList = pTab->pTrigger;
+  while( p ){
+    Trigger *pTrig = (Trigger *)sqliteHashData(p);
+    if( pTrig->pTabSchema==pTab->pSchema
+     && pTrig->table
+     && 0==sqlite3StrICmp(pTrig->table, pTab->zName)
+     && (pTrig->pTabSchema!=pTmpSchema || pTrig->bReturning)
+    ){
+      pTrig->pNext = pList;
+      pList = pTrig;
+    }else if( pTrig->op==TK_RETURNING ){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      assert( pParse->db->pVtabCtx==0 );
+#endif
+      assert( pParse->bReturning );
+      assert( &(pParse->u1.pReturning->retTrig) == pTrig );
+      pTrig->table = pTab->zName;
+      pTrig->pTabSchema = pTab->pSchema;
+      pTrig->pNext = pList;
+      pList = pTrig;
+    }
+    p = sqliteHashNext(p);
+  }
+#if 0
+  if( pList ){
+    Trigger *pX;
+    printf("Triggers for %s:", pTab->zName);
+    for(pX=pList; pX; pX=pX->pNext){
+      printf(" %s", pX->zName);
+    }
+    printf("\n");
+    fflush(stdout);
+  }
+#endif
+  return pList;
+}
+
+/*
+** This is called by the parser when it sees a CREATE TRIGGER statement
+** up to the point of the BEGIN before the trigger actions.  A Trigger
+** structure is generated based on the information available and stored
+** in pParse->pNewTrigger.  After the trigger actions have been parsed, the
+** sqlite3FinishTrigger() function is called to complete the trigger
+** construction process.
+*/
+SQLITE_PRIVATE void sqlite3BeginTrigger(
+  Parse *pParse,      /* The parse context of the CREATE TRIGGER statement */
+  Token *pName1,      /* The name of the trigger */
+  Token *pName2,      /* The name of the trigger */
+  int tr_tm,          /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
+  int op,             /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
+  IdList *pColumns,   /* column list if this is an UPDATE OF trigger */
+  SrcList *pTableName,/* The name of the table/view the trigger applies to */
+  Expr *pWhen,        /* WHEN clause */
+  int isTemp,         /* True if the TEMPORARY keyword is present */
+  int noErr           /* Suppress errors if the trigger already exists */
+){
+  Trigger *pTrigger = 0;  /* The new trigger */
+  Table *pTab;            /* Table that the trigger fires off of */
+  char *zName = 0;        /* Name of the trigger */
+  sqlite3 *db = pParse->db;  /* The database connection */
+  int iDb;                /* The database to store the trigger in */
+  Token *pName;           /* The unqualified db name */
+  DbFixer sFix;           /* State vector for the DB fixer */
+
+  assert( pName1!=0 );   /* pName1->z might be NULL, but not pName1 itself */
+  assert( pName2!=0 );
+  assert( op==TK_INSERT || op==TK_UPDATE || op==TK_DELETE );
+  assert( op>0 && op<0xff );
+  if( isTemp ){
+    /* If TEMP was specified, then the trigger name may not be qualified. */
+    if( pName2->n>0 ){
+      sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
+      goto trigger_cleanup;
+    }
+    iDb = 1;
+    pName = pName1;
+  }else{
+    /* Figure out the db that the trigger will be created in */
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+    if( iDb<0 ){
+      goto trigger_cleanup;
+    }
+  }
+  if( !pTableName || db->mallocFailed ){
+    goto trigger_cleanup;
+  }
+
+  /* A long-standing parser bug is that this syntax was allowed:
+  **
+  **    CREATE TRIGGER attached.demo AFTER INSERT ON attached.tab ....
+  **                                                 ^^^^^^^^
+  **
+  ** To maintain backwards compatibility, ignore the database
+  ** name on pTableName if we are reparsing out of the schema table
+  */
+  if( db->init.busy && iDb!=1 ){
+    assert( pTableName->a[0].fg.fixedSchema==0 );
+    assert( pTableName->a[0].fg.isSubquery==0 );
+    sqlite3DbFree(db, pTableName->a[0].u4.zDatabase);
+    pTableName->a[0].u4.zDatabase = 0;
+  }
+
+  /* If the trigger name was unqualified, and the table is a temp table,
+  ** then set iDb to 1 to create the trigger in the temporary database.
+  ** If sqlite3SrcListLookup() returns 0, indicating the table does not
+  ** exist, the error is caught by the block below.
+  */
+  pTab = sqlite3SrcListLookup(pParse, pTableName);
+  if( db->init.busy==0 && pName2->n==0 && pTab
+        && pTab->pSchema==db->aDb[1].pSchema ){
+    iDb = 1;
+  }
+
+  /* Ensure the table name matches database name and that the table exists */
+  if( db->mallocFailed ) goto trigger_cleanup;
+  assert( pTableName->nSrc==1 );
+  sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName);
+  if( sqlite3FixSrcList(&sFix, pTableName) ){
+    goto trigger_cleanup;
+  }
+  pTab = sqlite3SrcListLookup(pParse, pTableName);
+  if( !pTab ){
+    /* The table does not exist. */
+    goto trigger_orphan_error;
+  }
+  if( IsVirtual(pTab) ){
+    sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables");
+    goto trigger_orphan_error;
+  }
+  if( (pTab->tabFlags & TF_Shadow)!=0 && sqlite3ReadOnlyShadowTables(db) ){
+    sqlite3ErrorMsg(pParse, "cannot create triggers on shadow tables");
+    goto trigger_orphan_error;
+  }
+
+  /* Check that the trigger name is not reserved and that no trigger of the
+  ** specified name exists */
+  zName = sqlite3NameFromToken(db, pName);
+  if( zName==0 ){
+    assert( db->mallocFailed );
+    goto trigger_cleanup;
+  }
+  if( sqlite3CheckObjectName(pParse, zName, "trigger", pTab->zName) ){
+    goto trigger_cleanup;
+  }
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  if( !IN_RENAME_OBJECT ){
+    if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash),zName) ){
+      if( !noErr ){
+        sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
+      }else{
+        assert( !db->init.busy );
+        sqlite3CodeVerifySchema(pParse, iDb);
+        VVA_ONLY( pParse->ifNotExists = 1; )
+      }
+      goto trigger_cleanup;
+    }
+  }
+
+  /* Do not create a trigger on a system table */
+  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
+    sqlite3ErrorMsg(pParse, "cannot create trigger on system table");
+    goto trigger_cleanup;
+  }
+
+  /* INSTEAD of triggers are only for views and views only support INSTEAD
+  ** of triggers.
+  */
+  if( IsView(pTab) && tr_tm!=TK_INSTEAD ){
+    sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S",
+        (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName->a);
+    goto trigger_orphan_error;
+  }
+  if( !IsView(pTab) && tr_tm==TK_INSTEAD ){
+    sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
+        " trigger on table: %S", pTableName->a);
+    goto trigger_orphan_error;
+  }
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( !IN_RENAME_OBJECT ){
+    int iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    int code = SQLITE_CREATE_TRIGGER;
+    const char *zDb = db->aDb[iTabDb].zDbSName;
+    const char *zDbTrig = isTemp ? db->aDb[1].zDbSName : zDb;
+    if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
+    if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
+      goto trigger_cleanup;
+    }
+    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){
+      goto trigger_cleanup;
+    }
+  }
+#endif
+
+  /* INSTEAD OF triggers can only appear on views and BEFORE triggers
+  ** cannot appear on views.  So we might as well translate every
+  ** INSTEAD OF trigger into a BEFORE trigger.  It simplifies code
+  ** elsewhere.
+  */
+  if (tr_tm == TK_INSTEAD){
+    tr_tm = TK_BEFORE;
+  }
+
+  /* Build the Trigger object */
+  pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger));
+  if( pTrigger==0 ) goto trigger_cleanup;
+  pTrigger->zName = zName;
+  zName = 0;
+  pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
+  pTrigger->pSchema = db->aDb[iDb].pSchema;
+  pTrigger->pTabSchema = pTab->pSchema;
+  pTrigger->op = (u8)op;
+  pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameTokenRemap(pParse, pTrigger->table, pTableName->a[0].zName);
+    pTrigger->pWhen = pWhen;
+    pWhen = 0;
+  }else{
+    pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
+  }
+  pTrigger->pColumns = pColumns;
+  pColumns = 0;
+  assert( pParse->pNewTrigger==0 );
+  pParse->pNewTrigger = pTrigger;
+
+trigger_cleanup:
+  sqlite3DbFree(db, zName);
+  sqlite3SrcListDelete(db, pTableName);
+  sqlite3IdListDelete(db, pColumns);
+  sqlite3ExprDelete(db, pWhen);
+  if( !pParse->pNewTrigger ){
+    sqlite3DeleteTrigger(db, pTrigger);
+  }else{
+    assert( pParse->pNewTrigger==pTrigger );
+  }
+  return;
+
+trigger_orphan_error:
+  if( db->init.iDb==1 ){
+    /* Ticket #3810.
+    ** Normally, whenever a table is dropped, all associated triggers are
+    ** dropped too.  But if a TEMP trigger is created on a non-TEMP table
+    ** and the table is dropped by a different database connection, the
+    ** trigger is not visible to the database connection that does the
+    ** drop so the trigger cannot be dropped.  This results in an
+    ** "orphaned trigger" - a trigger whose associated table is missing.
+    **
+    ** 2020-11-05 see also https://sqlite.org/forum/forumpost/157dc791df
+    */
+    db->init.orphanTrigger = 1;
+  }
+  goto trigger_cleanup;
+}
+
+/*
+** This routine is called after all of the trigger actions have been parsed
+** in order to complete the process of building the trigger.
+*/
+SQLITE_PRIVATE void sqlite3FinishTrigger(
+  Parse *pParse,          /* Parser context */
+  TriggerStep *pStepList, /* The triggered program */
+  Token *pAll             /* Token that describes the complete CREATE TRIGGER */
+){
+  Trigger *pTrig = pParse->pNewTrigger;   /* Trigger being finished */
+  char *zName;                            /* Name of trigger */
+  sqlite3 *db = pParse->db;               /* The database */
+  DbFixer sFix;                           /* Fixer object */
+  int iDb;                                /* Database containing the trigger */
+  Token nameToken;                        /* Trigger name for error reporting */
+
+  pParse->pNewTrigger = 0;
+  if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup;
+  zName = pTrig->zName;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
+  pTrig->step_list = pStepList;
+  while( pStepList ){
+    pStepList->pTrig = pTrig;
+    pStepList = pStepList->pNext;
+  }
+  sqlite3TokenInit(&nameToken, pTrig->zName);
+  sqlite3FixInit(&sFix, pParse, iDb, "trigger", &nameToken);
+  if( sqlite3FixTriggerStep(&sFix, pTrig->step_list)
+   || sqlite3FixExpr(&sFix, pTrig->pWhen)
+  ){
+    goto triggerfinish_cleanup;
+  }
+
+#ifndef SQLITE_OMIT_ALTERTABLE
+  if( IN_RENAME_OBJECT ){
+    assert( !db->init.busy );
+    pParse->pNewTrigger = pTrig;
+    pTrig = 0;
+  }else
+#endif
+
+  /* if we are not initializing,
+  ** build the sqlite_schema entry
+  */
+  if( !db->init.busy ){
+    Vdbe *v;
+    char *z;
+
+    /* If this is a new CREATE TABLE statement, and if shadow tables
+    ** are read-only, and the trigger makes a change to a shadow table,
+    ** then raise an error - do not allow the trigger to be created. */
+    if( sqlite3ReadOnlyShadowTables(db) ){
+      TriggerStep *pStep;
+      for(pStep=pTrig->step_list; pStep; pStep=pStep->pNext){
+        if( pStep->zTarget!=0
+         && sqlite3ShadowTableName(db, pStep->zTarget)
+        ){
+          sqlite3ErrorMsg(pParse,
+            "trigger \"%s\" may not write to shadow table \"%s\"",
+            pTrig->zName, pStep->zTarget);
+          goto triggerfinish_cleanup;
+        }
+      }
+    }
+
+    /* Make an entry in the sqlite_schema table */
+    v = sqlite3GetVdbe(pParse);
+    if( v==0 ) goto triggerfinish_cleanup;
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n);
+    testcase( z==0 );
+    sqlite3NestedParse(pParse,
+       "INSERT INTO %Q." LEGACY_SCHEMA_TABLE
+       " VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')",
+       db->aDb[iDb].zDbSName, zName,
+       pTrig->table, z);
+    sqlite3DbFree(db, z);
+    sqlite3ChangeCookie(pParse, iDb);
+    sqlite3VdbeAddParseSchemaOp(v, iDb,
+        sqlite3MPrintf(db, "type='trigger' AND name='%q'", zName), 0);
+  }
+
+  if( db->init.busy ){
+    Trigger *pLink = pTrig;
+    Hash *pHash = &db->aDb[iDb].pSchema->trigHash;
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    assert( pLink!=0 );
+    pTrig = sqlite3HashInsert(pHash, zName, pTrig);
+    if( pTrig ){
+      sqlite3OomFault(db);
+    }else if( pLink->pSchema==pLink->pTabSchema ){
+      Table *pTab;
+      pTab = sqlite3HashFind(&pLink->pTabSchema->tblHash, pLink->table);
+      assert( pTab!=0 );
+      pLink->pNext = pTab->pTrigger;
+      pTab->pTrigger = pLink;
+    }
+  }
+
+triggerfinish_cleanup:
+  sqlite3DeleteTrigger(db, pTrig);
+  assert( IN_RENAME_OBJECT || !pParse->pNewTrigger );
+  sqlite3DeleteTriggerStep(db, pStepList);
+}
+
+/*
+** Duplicate a range of text from an SQL statement, then convert all
+** whitespace characters into ordinary space characters.
+*/
+static char *triggerSpanDup(sqlite3 *db, const char *zStart, const char *zEnd){
+  char *z = sqlite3DbSpanDup(db, zStart, zEnd);
+  int i;
+  if( z ) for(i=0; z[i]; i++) if( sqlite3Isspace(z[i]) ) z[i] = ' ';
+  return z;
+}
+
+/*
+** Turn a SELECT statement (that the pSelect parameter points to) into
+** a trigger step.  Return a pointer to a TriggerStep structure.
+**
+** The parser calls this routine when it finds a SELECT statement in
+** body of a TRIGGER.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerSelectStep(
+  sqlite3 *db,                /* Database connection */
+  Select *pSelect,            /* The SELECT statement */
+  const char *zStart,         /* Start of SQL text */
+  const char *zEnd            /* End of SQL text */
+){
+  TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
+  if( pTriggerStep==0 ) {
+    sqlite3SelectDelete(db, pSelect);
+    return 0;
+  }
+  pTriggerStep->op = TK_SELECT;
+  pTriggerStep->pSelect = pSelect;
+  pTriggerStep->orconf = OE_Default;
+  pTriggerStep->zSpan = triggerSpanDup(db, zStart, zEnd);
+  return pTriggerStep;
+}
+
+/*
+** Allocate space to hold a new trigger step.  The allocated space
+** holds both the TriggerStep object and the TriggerStep.target.z string.
+**
+** If an OOM error occurs, NULL is returned and db->mallocFailed is set.
+*/
+static TriggerStep *triggerStepAllocate(
+  Parse *pParse,              /* Parser context */
+  u8 op,                      /* Trigger opcode */
+  Token *pName,               /* The target name */
+  const char *zStart,         /* Start of SQL text */
+  const char *zEnd            /* End of SQL text */
+){
+  sqlite3 *db = pParse->db;
+  TriggerStep *pTriggerStep;
+
+  if( pParse->nErr ) return 0;
+  pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep) + pName->n + 1);
+  if( pTriggerStep ){
+    char *z = (char*)&pTriggerStep[1];
+    memcpy(z, pName->z, pName->n);
+    sqlite3Dequote(z);
+    pTriggerStep->zTarget = z;
+    pTriggerStep->op = op;
+    pTriggerStep->zSpan = triggerSpanDup(db, zStart, zEnd);
+    if( IN_RENAME_OBJECT ){
+      sqlite3RenameTokenMap(pParse, pTriggerStep->zTarget, pName);
+    }
+  }
+  return pTriggerStep;
+}
+
+/*
+** Build a trigger step out of an INSERT statement.  Return a pointer
+** to the new trigger step.
+**
+** The parser calls this routine when it sees an INSERT inside the
+** body of a trigger.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerInsertStep(
+  Parse *pParse,      /* Parser */
+  Token *pTableName,  /* Name of the table into which we insert */
+  IdList *pColumn,    /* List of columns in pTableName to insert into */
+  Select *pSelect,    /* A SELECT statement that supplies values */
+  u8 orconf,          /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
+  Upsert *pUpsert,    /* ON CONFLICT clauses for upsert */
+  const char *zStart, /* Start of SQL text */
+  const char *zEnd    /* End of SQL text */
+){
+  sqlite3 *db = pParse->db;
+  TriggerStep *pTriggerStep;
+
+  assert(pSelect != 0 || db->mallocFailed);
+
+  pTriggerStep = triggerStepAllocate(pParse, TK_INSERT, pTableName,zStart,zEnd);
+  if( pTriggerStep ){
+    if( IN_RENAME_OBJECT ){
+      pTriggerStep->pSelect = pSelect;
+      pSelect = 0;
+    }else{
+      pTriggerStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
+    }
+    pTriggerStep->pIdList = pColumn;
+    pTriggerStep->pUpsert = pUpsert;
+    pTriggerStep->orconf = orconf;
+    if( pUpsert ){
+      sqlite3HasExplicitNulls(pParse, pUpsert->pUpsertTarget);
+    }
+  }else{
+    testcase( pColumn );
+    sqlite3IdListDelete(db, pColumn);
+    testcase( pUpsert );
+    sqlite3UpsertDelete(db, pUpsert);
+  }
+  sqlite3SelectDelete(db, pSelect);
+
+  return pTriggerStep;
+}
+
+/*
+** Construct a trigger step that implements an UPDATE statement and return
+** a pointer to that trigger step.  The parser calls this routine when it
+** sees an UPDATE statement inside the body of a CREATE TRIGGER.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerUpdateStep(
+  Parse *pParse,          /* Parser */
+  Token *pTableName,   /* Name of the table to be updated */
+  SrcList *pFrom,      /* FROM clause for an UPDATE-FROM, or NULL */
+  ExprList *pEList,    /* The SET clause: list of column and new values */
+  Expr *pWhere,        /* The WHERE clause */
+  u8 orconf,           /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
+  const char *zStart,  /* Start of SQL text */
+  const char *zEnd     /* End of SQL text */
+){
+  sqlite3 *db = pParse->db;
+  TriggerStep *pTriggerStep;
+
+  pTriggerStep = triggerStepAllocate(pParse, TK_UPDATE, pTableName,zStart,zEnd);
+  if( pTriggerStep ){
+    if( IN_RENAME_OBJECT ){
+      pTriggerStep->pExprList = pEList;
+      pTriggerStep->pWhere = pWhere;
+      pTriggerStep->pFrom = pFrom;
+      pEList = 0;
+      pWhere = 0;
+      pFrom = 0;
+    }else{
+      pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE);
+      pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
+      pTriggerStep->pFrom = sqlite3SrcListDup(db, pFrom, EXPRDUP_REDUCE);
+    }
+    pTriggerStep->orconf = orconf;
+  }
+  sqlite3ExprListDelete(db, pEList);
+  sqlite3ExprDelete(db, pWhere);
+  sqlite3SrcListDelete(db, pFrom);
+  return pTriggerStep;
+}
+
+/*
+** Construct a trigger step that implements a DELETE statement and return
+** a pointer to that trigger step.  The parser calls this routine when it
+** sees a DELETE statement inside the body of a CREATE TRIGGER.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerDeleteStep(
+  Parse *pParse,          /* Parser */
+  Token *pTableName,      /* The table from which rows are deleted */
+  Expr *pWhere,           /* The WHERE clause */
+  const char *zStart,     /* Start of SQL text */
+  const char *zEnd        /* End of SQL text */
+){
+  sqlite3 *db = pParse->db;
+  TriggerStep *pTriggerStep;
+
+  pTriggerStep = triggerStepAllocate(pParse, TK_DELETE, pTableName,zStart,zEnd);
+  if( pTriggerStep ){
+    if( IN_RENAME_OBJECT ){
+      pTriggerStep->pWhere = pWhere;
+      pWhere = 0;
+    }else{
+      pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
+    }
+    pTriggerStep->orconf = OE_Default;
+  }
+  sqlite3ExprDelete(db, pWhere);
+  return pTriggerStep;
+}
+
+/*
+** Recursively delete a Trigger structure
+*/
+SQLITE_PRIVATE void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){
+  if( pTrigger==0 || pTrigger->bReturning ) return;
+  sqlite3DeleteTriggerStep(db, pTrigger->step_list);
+  sqlite3DbFree(db, pTrigger->zName);
+  sqlite3DbFree(db, pTrigger->table);
+  sqlite3ExprDelete(db, pTrigger->pWhen);
+  sqlite3IdListDelete(db, pTrigger->pColumns);
+  sqlite3DbFree(db, pTrigger);
+}
+
+/*
+** This function is called to drop a trigger from the database schema.
+**
+** This may be called directly from the parser and therefore identifies
+** the trigger by name.  The sqlite3DropTriggerPtr() routine does the
+** same job as this routine except it takes a pointer to the trigger
+** instead of the trigger name.
+**/
+SQLITE_PRIVATE void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
+  Trigger *pTrigger = 0;
+  int i;
+  const char *zDb;
+  const char *zName;
+  sqlite3 *db = pParse->db;
+
+  if( db->mallocFailed ) goto drop_trigger_cleanup;
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    goto drop_trigger_cleanup;
+  }
+
+  assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 && pName->a[0].fg.isSubquery==0 );
+  zDb = pName->a[0].u4.zDatabase;
+  zName = pName->a[0].zName;
+  assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );
+  for(i=OMIT_TEMPDB; i<db->nDb; i++){
+    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
+    if( zDb && sqlite3DbIsNamed(db, j, zDb)==0 ) continue;
+    assert( sqlite3SchemaMutexHeld(db, j, 0) );
+    pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName);
+    if( pTrigger ) break;
+  }
+  if( !pTrigger ){
+    if( !noErr ){
+      sqlite3ErrorMsg(pParse, "no such trigger: %S", pName->a);
+    }else{
+      sqlite3CodeVerifyNamedSchema(pParse, zDb);
+    }
+    pParse->checkSchema = 1;
+    goto drop_trigger_cleanup;
+  }
+  sqlite3DropTriggerPtr(pParse, pTrigger);
+
+drop_trigger_cleanup:
+  sqlite3SrcListDelete(db, pName);
+}
+
+/*
+** Return a pointer to the Table structure for the table that a trigger
+** is set on.
+*/
+static Table *tableOfTrigger(Trigger *pTrigger){
+  return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table);
+}
+
+
+/*
+** Drop a trigger given a pointer to that trigger.
+*/
+SQLITE_PRIVATE void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
+  Table   *pTable;
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+  pTable = tableOfTrigger(pTrigger);
+  assert( (pTable && pTable->pSchema==pTrigger->pSchema) || iDb==1 );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( pTable ){
+    int code = SQLITE_DROP_TRIGGER;
+    const char *zDb = db->aDb[iDb].zDbSName;
+    const char *zTab = SCHEMA_TABLE(iDb);
+    if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
+    if( sqlite3AuthCheck(pParse, code, pTrigger->zName, pTable->zName, zDb) ||
+      sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
+      return;
+    }
+  }
+#endif
+
+  /* Generate code to destroy the database record of the trigger.
+  */
+  if( (v = sqlite3GetVdbe(pParse))!=0 ){
+    sqlite3NestedParse(pParse,
+       "DELETE FROM %Q." LEGACY_SCHEMA_TABLE " WHERE name=%Q AND type='trigger'",
+       db->aDb[iDb].zDbSName, pTrigger->zName
+    );
+    sqlite3ChangeCookie(pParse, iDb);
+    sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0);
+  }
+}
+
+/*
+** Remove a trigger from the hash tables of the sqlite* pointer.
+*/
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
+  Trigger *pTrigger;
+  Hash *pHash;
+
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  pHash = &(db->aDb[iDb].pSchema->trigHash);
+  pTrigger = sqlite3HashInsert(pHash, zName, 0);
+  if( ALWAYS(pTrigger) ){
+    if( pTrigger->pSchema==pTrigger->pTabSchema ){
+      Table *pTab = tableOfTrigger(pTrigger);
+      if( pTab ){
+        Trigger **pp;
+        for(pp=&pTab->pTrigger; *pp; pp=&((*pp)->pNext)){
+          if( *pp==pTrigger ){
+            *pp = (*pp)->pNext;
+            break;
+          }
+        }
+      }
+    }
+    sqlite3DeleteTrigger(db, pTrigger);
+    db->mDbFlags |= DBFLAG_SchemaChange;
+  }
+}
+
+/*
+** pEList is the SET clause of an UPDATE statement.  Each entry
+** in pEList is of the format <id>=<expr>.  If any of the entries
+** in pEList have an <id> which matches an identifier in pIdList,
+** then return TRUE.  If pIdList==NULL, then it is considered a
+** wildcard that matches anything.  Likewise if pEList==NULL then
+** it matches anything so always return true.  Return false only
+** if there is no match.
+*/
+static int checkColumnOverlap(IdList *pIdList, ExprList *pEList){
+  int e;
+  if( pIdList==0 || NEVER(pEList==0) ) return 1;
+  for(e=0; e<pEList->nExpr; e++){
+    if( sqlite3IdListIndex(pIdList, pEList->a[e].zEName)>=0 ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Return true if any TEMP triggers exist
+*/
+static int tempTriggersExist(sqlite3 *db){
+  if( NEVER(db->aDb[1].pSchema==0) ) return 0;
+  if( sqliteHashFirst(&db->aDb[1].pSchema->trigHash)==0 ) return 0;
+  return 1;
+}
+
+/*
+** Return a list of all triggers on table pTab if there exists at least
+** one trigger that must be fired when an operation of type 'op' is
+** performed on the table, and, if that operation is an UPDATE, if at
+** least one of the columns in pChanges is being modified.
+*/
+static SQLITE_NOINLINE Trigger *triggersReallyExist(
+  Parse *pParse,          /* Parse context */
+  Table *pTab,            /* The table the contains the triggers */
+  int op,                 /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
+  ExprList *pChanges,     /* Columns that change in an UPDATE statement */
+  int *pMask              /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
+){
+  int mask = 0;
+  Trigger *pList = 0;
+  Trigger *p;
+
+  pList = sqlite3TriggerList(pParse, pTab);
+  assert( pList==0 || IsVirtual(pTab)==0
+           || (pList->bReturning && pList->pNext==0) );
+  if( pList!=0 ){
+    p = pList;
+    if( (pParse->db->flags & SQLITE_EnableTrigger)==0
+     && pTab->pTrigger!=0
+    ){
+      /* The SQLITE_DBCONFIG_ENABLE_TRIGGER setting is off.  That means that
+      ** only TEMP triggers are allowed.  Truncate the pList so that it
+      ** includes only TEMP triggers */
+      if( pList==pTab->pTrigger ){
+        pList = 0;
+        goto exit_triggers_exist;
+      }
+      while( ALWAYS(p->pNext) && p->pNext!=pTab->pTrigger ) p = p->pNext;
+      p->pNext = 0;
+      p = pList;
+    }
+    do{
+      if( p->op==op && checkColumnOverlap(p->pColumns, pChanges) ){
+        mask |= p->tr_tm;
+      }else if( p->op==TK_RETURNING ){
+        /* The first time a RETURNING trigger is seen, the "op" value tells
+        ** us what time of trigger it should be. */
+        assert( sqlite3IsToplevel(pParse) );
+        p->op = op;
+        if( IsVirtual(pTab) ){
+          if( op!=TK_INSERT ){
+            sqlite3ErrorMsg(pParse,
+              "%s RETURNING is not available on virtual tables",
+              op==TK_DELETE ? "DELETE" : "UPDATE");
+          }
+          p->tr_tm = TRIGGER_BEFORE;
+        }else{
+          p->tr_tm = TRIGGER_AFTER;
+        }
+        mask |= p->tr_tm;
+      }else if( p->bReturning && p->op==TK_INSERT && op==TK_UPDATE
+                && sqlite3IsToplevel(pParse) ){
+        /* Also fire a RETURNING trigger for an UPSERT */
+        mask |= p->tr_tm;
+      }
+      p = p->pNext;
+    }while( p );
+  }
+exit_triggers_exist:
+  if( pMask ){
+    *pMask = mask;
+  }
+  return (mask ? pList : 0);
+}
+SQLITE_PRIVATE Trigger *sqlite3TriggersExist(
+  Parse *pParse,          /* Parse context */
+  Table *pTab,            /* The table the contains the triggers */
+  int op,                 /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
+  ExprList *pChanges,     /* Columns that change in an UPDATE statement */
+  int *pMask              /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
+){
+  assert( pTab!=0 );
+  if( (pTab->pTrigger==0 && !tempTriggersExist(pParse->db))
+   || pParse->disableTriggers
+  ){
+    if( pMask ) *pMask = 0;
+    return 0;
+  }
+  return triggersReallyExist(pParse,pTab,op,pChanges,pMask);
+}
+
+/*
+** Convert the pStep->zTarget string into a SrcList and return a pointer
+** to that SrcList.
+**
+** This routine adds a specific database name, if needed, to the target when
+** forming the SrcList.  This prevents a trigger in one database from
+** referring to a target in another database.  An exception is when the
+** trigger is in TEMP in which case it can refer to any other database it
+** wants.
+*/
+SQLITE_PRIVATE SrcList *sqlite3TriggerStepSrc(
+  Parse *pParse,       /* The parsing context */
+  TriggerStep *pStep   /* The trigger containing the target token */
+){
+  sqlite3 *db = pParse->db;
+  SrcList *pSrc;                  /* SrcList to be returned */
+  char *zName = sqlite3DbStrDup(db, pStep->zTarget);
+  pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
+  assert( pSrc==0 || pSrc->nSrc==1 );
+  assert( zName || pSrc==0 );
+  if( pSrc ){
+    Schema *pSchema = pStep->pTrig->pSchema;
+    pSrc->a[0].zName = zName;
+    if( pSchema!=db->aDb[1].pSchema ){
+      assert( pSrc->a[0].fg.fixedSchema || pSrc->a[0].u4.zDatabase==0 );
+      pSrc->a[0].u4.pSchema = pSchema;
+      pSrc->a[0].fg.fixedSchema = 1;
+    }
+    if( pStep->pFrom ){
+      SrcList *pDup = sqlite3SrcListDup(db, pStep->pFrom, 0);
+      if( pDup && pDup->nSrc>1 && !IN_RENAME_OBJECT ){
+        Select *pSubquery;
+        Token as;
+        pSubquery = sqlite3SelectNew(pParse,0,pDup,0,0,0,0,SF_NestedFrom,0);
+        as.n = 0;
+        as.z = 0;
+        pDup = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&as,pSubquery,0);
+      }
+      pSrc = sqlite3SrcListAppendList(pParse, pSrc, pDup);
+    }
+  }else{
+    sqlite3DbFree(db, zName);
+  }
+  return pSrc;
+}
+
+/*
+** Return true if the pExpr term from the RETURNING clause argument
+** list is of the form "*".  Raise an error if the terms if of the
+** form "table.*".
+*/
+static int isAsteriskTerm(
+  Parse *pParse,      /* Parsing context */
+  Expr *pTerm         /* A term in the RETURNING clause */
+){
+  assert( pTerm!=0 );
+  if( pTerm->op==TK_ASTERISK ) return 1;
+  if( pTerm->op!=TK_DOT ) return 0;
+  assert( pTerm->pRight!=0 );
+  assert( pTerm->pLeft!=0 );
+  if( pTerm->pRight->op!=TK_ASTERISK ) return 0;
+  sqlite3ErrorMsg(pParse, "RETURNING may not use \"TABLE.*\" wildcards");
+  return 1;
+}
+
+/* The input list pList is the list of result set terms from a RETURNING
+** clause.  The table that we are returning from is pTab.
+**
+** This routine makes a copy of the pList, and at the same time expands
+** any "*" wildcards to be the complete set of columns from pTab.
+*/
+static ExprList *sqlite3ExpandReturning(
+  Parse *pParse,        /* Parsing context */
+  ExprList *pList,      /* The arguments to RETURNING */
+  Table *pTab           /* The table being updated */
+){
+  ExprList *pNew = 0;
+  sqlite3 *db = pParse->db;
+  int i;
+
+  for(i=0; i<pList->nExpr; i++){
+    Expr *pOldExpr = pList->a[i].pExpr;
+    if( NEVER(pOldExpr==0) ) continue;
+    if( isAsteriskTerm(pParse, pOldExpr) ){
+      int jj;
+      for(jj=0; jj<pTab->nCol; jj++){
+        Expr *pNewExpr;
+        if( IsHiddenColumn(pTab->aCol+jj) ) continue;
+        pNewExpr = sqlite3Expr(db, TK_ID, pTab->aCol[jj].zCnName);
+        pNew = sqlite3ExprListAppend(pParse, pNew, pNewExpr);
+        if( !db->mallocFailed ){
+          struct ExprList_item *pItem = &pNew->a[pNew->nExpr-1];
+          pItem->zEName = sqlite3DbStrDup(db, pTab->aCol[jj].zCnName);
+          pItem->fg.eEName = ENAME_NAME;
+        }
+      }
+    }else{
+      Expr *pNewExpr = sqlite3ExprDup(db, pOldExpr, 0);
+      pNew = sqlite3ExprListAppend(pParse, pNew, pNewExpr);
+      if( !db->mallocFailed && ALWAYS(pList->a[i].zEName!=0) ){
+        struct ExprList_item *pItem = &pNew->a[pNew->nExpr-1];
+        pItem->zEName = sqlite3DbStrDup(db, pList->a[i].zEName);
+        pItem->fg.eEName = pList->a[i].fg.eEName;
+      }
+    }
+  }
+  return pNew;
+}
+
+/* If the Expr node is a subquery or an EXISTS operator or an IN operator that
+** uses a subquery, and if the subquery is SF_Correlated, then mark the
+** expression as EP_VarSelect.
+*/
+static int sqlite3ReturningSubqueryVarSelect(Walker *NotUsed, Expr *pExpr){
+  UNUSED_PARAMETER(NotUsed);
+  if( ExprUseXSelect(pExpr)
+   && (pExpr->x.pSelect->selFlags & SF_Correlated)!=0
+  ){
+    testcase( ExprHasProperty(pExpr, EP_VarSelect) );
+    ExprSetProperty(pExpr, EP_VarSelect);
+  }
+  return WRC_Continue;
+}
+
+
+/*
+** If the SELECT references the table pWalker->u.pTab, then do two things:
+**
+**    (1) Mark the SELECT as as SF_Correlated.
+**    (2) Set pWalker->eCode to non-zero so that the caller will know
+**        that (1) has happened.
+*/
+static int sqlite3ReturningSubqueryCorrelated(Walker *pWalker, Select *pSelect){
+  int i;
+  SrcList *pSrc;
+  assert( pSelect!=0 );
+  pSrc = pSelect->pSrc;
+  assert( pSrc!=0 );
+  for(i=0; i<pSrc->nSrc; i++){
+    if( pSrc->a[i].pSTab==pWalker->u.pTab ){
+      testcase( pSelect->selFlags & SF_Correlated );
+      pSelect->selFlags |= SF_Correlated;
+      pWalker->eCode = 1;
+      break;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Scan the expression list that is the argument to RETURNING looking
+** for subqueries that depend on the table which is being modified in the
+** statement that is hosting the RETURNING clause (pTab).  Mark all such
+** subqueries as SF_Correlated.  If the subqueries are part of an
+** expression, mark the expression as EP_VarSelect.
+**
+** https://sqlite.org/forum/forumpost/2c83569ce8945d39
+*/
+static void sqlite3ProcessReturningSubqueries(
+  ExprList *pEList,
+  Table *pTab
+){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.xSelectCallback = sqlite3ReturningSubqueryCorrelated;
+  w.u.pTab = pTab;
+  sqlite3WalkExprList(&w, pEList);
+  if( w.eCode ){
+    w.xExprCallback = sqlite3ReturningSubqueryVarSelect;
+    w.xSelectCallback = sqlite3SelectWalkNoop;
+    sqlite3WalkExprList(&w, pEList);
+  }
+}
+
+/*
+** Generate code for the RETURNING trigger.  Unlike other triggers
+** that invoke a subprogram in the bytecode, the code for RETURNING
+** is generated in-line.
+*/
+static void codeReturningTrigger(
+  Parse *pParse,       /* Parse context */
+  Trigger *pTrigger,   /* The trigger step that defines the RETURNING */
+  Table *pTab,         /* The table to code triggers from */
+  int regIn            /* The first in an array of registers */
+){
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
+  ExprList *pNew;
+  Returning *pReturning;
+  Select sSelect;
+  SrcList sFrom;
+
+  assert( v!=0 );
+  if( !pParse->bReturning ){
+    /* This RETURNING trigger must be for a different statement as
+    ** this statement lacks a RETURNING clause. */
+    return;
+  }
+  assert( db->pParse==pParse );
+  pReturning = pParse->u1.pReturning;
+  if( pTrigger != &(pReturning->retTrig) ){
+    /* This RETURNING trigger is for a different statement */
+    return;
+  }
+  memset(&sSelect, 0, sizeof(sSelect));
+  memset(&sFrom, 0, sizeof(sFrom));
+  sSelect.pEList = sqlite3ExprListDup(db, pReturning->pReturnEL, 0);
+  sSelect.pSrc = &sFrom;
+  sFrom.nSrc = 1;
+  sFrom.a[0].pSTab = pTab;
+  sFrom.a[0].zName = pTab->zName; /* tag-20240424-1 */
+  sFrom.a[0].iCursor = -1;
+  sqlite3SelectPrep(pParse, &sSelect, 0);
+  if( pParse->nErr==0 ){
+    assert( db->mallocFailed==0 );
+    sqlite3GenerateColumnNames(pParse, &sSelect);
+  }
+  sqlite3ExprListDelete(db, sSelect.pEList);
+  pNew = sqlite3ExpandReturning(pParse, pReturning->pReturnEL, pTab);
+  if( pParse->nErr==0 ){
+    NameContext sNC;
+    memset(&sNC, 0, sizeof(sNC));
+    if( pReturning->nRetCol==0 ){
+      pReturning->nRetCol = pNew->nExpr;
+      pReturning->iRetCur = pParse->nTab++;
+    }
+    sNC.pParse = pParse;
+    sNC.uNC.iBaseReg = regIn;
+    sNC.ncFlags = NC_UBaseReg;
+    pParse->eTriggerOp = pTrigger->op;
+    pParse->pTriggerTab = pTab;
+    if( sqlite3ResolveExprListNames(&sNC, pNew)==SQLITE_OK
+     && ALWAYS(!db->mallocFailed)
+    ){
+      int i;
+      int nCol = pNew->nExpr;
+      int reg = pParse->nMem+1;
+      sqlite3ProcessReturningSubqueries(pNew, pTab);
+      pParse->nMem += nCol+2;
+      pReturning->iRetReg = reg;
+      for(i=0; i<nCol; i++){
+        Expr *pCol = pNew->a[i].pExpr;
+        assert( pCol!=0 ); /* Due to !db->mallocFailed ~9 lines above */
+        sqlite3ExprCodeFactorable(pParse, pCol, reg+i);
+        if( sqlite3ExprAffinity(pCol)==SQLITE_AFF_REAL ){
+          sqlite3VdbeAddOp1(v, OP_RealAffinity, reg+i);
+        }
+      }
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, reg, i, reg+i);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, pReturning->iRetCur, reg+i+1);
+      sqlite3VdbeAddOp3(v, OP_Insert, pReturning->iRetCur, reg+i, reg+i+1);
+    }
+  }
+  sqlite3ExprListDelete(db, pNew);
+  pParse->eTriggerOp = 0;
+  pParse->pTriggerTab = 0;
+}
+
+
+
+/*
+** Generate VDBE code for the statements inside the body of a single
+** trigger.
+*/
+static int codeTriggerProgram(
+  Parse *pParse,            /* The parser context */
+  TriggerStep *pStepList,   /* List of statements inside the trigger body */
+  int orconf                /* Conflict algorithm. (OE_Abort, etc) */
+){
+  TriggerStep *pStep;
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
+
+  assert( pParse->pTriggerTab && pParse->pToplevel );
+  assert( pStepList );
+  assert( v!=0 );
+  for(pStep=pStepList; pStep; pStep=pStep->pNext){
+    /* Figure out the ON CONFLICT policy that will be used for this step
+    ** of the trigger program. If the statement that caused this trigger
+    ** to fire had an explicit ON CONFLICT, then use it. Otherwise, use
+    ** the ON CONFLICT policy that was specified as part of the trigger
+    ** step statement. Example:
+    **
+    **   CREATE TRIGGER AFTER INSERT ON t1 BEGIN;
+    **     INSERT OR REPLACE INTO t2 VALUES(new.a, new.b);
+    **   END;
+    **
+    **   INSERT INTO t1 ... ;            -- insert into t2 uses REPLACE policy
+    **   INSERT OR IGNORE INTO t1 ... ;  -- insert into t2 uses IGNORE policy
+    */
+    pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf;
+    assert( pParse->okConstFactor==0 );
+
+#ifndef SQLITE_OMIT_TRACE
+    if( pStep->zSpan ){
+      sqlite3VdbeAddOp4(v, OP_Trace, 0x7fffffff, 1, 0,
+                        sqlite3MPrintf(db, "-- %s", pStep->zSpan),
+                        P4_DYNAMIC);
+    }
+#endif
+
+    switch( pStep->op ){
+      case TK_UPDATE: {
+        sqlite3Update(pParse,
+          sqlite3TriggerStepSrc(pParse, pStep),
+          sqlite3ExprListDup(db, pStep->pExprList, 0),
+          sqlite3ExprDup(db, pStep->pWhere, 0),
+          pParse->eOrconf, 0, 0, 0
+        );
+        sqlite3VdbeAddOp0(v, OP_ResetCount);
+        break;
+      }
+      case TK_INSERT: {
+        sqlite3Insert(pParse,
+          sqlite3TriggerStepSrc(pParse, pStep),
+          sqlite3SelectDup(db, pStep->pSelect, 0),
+          sqlite3IdListDup(db, pStep->pIdList),
+          pParse->eOrconf,
+          sqlite3UpsertDup(db, pStep->pUpsert)
+        );
+        sqlite3VdbeAddOp0(v, OP_ResetCount);
+        break;
+      }
+      case TK_DELETE: {
+        sqlite3DeleteFrom(pParse,
+          sqlite3TriggerStepSrc(pParse, pStep),
+          sqlite3ExprDup(db, pStep->pWhere, 0), 0, 0
+        );
+        sqlite3VdbeAddOp0(v, OP_ResetCount);
+        break;
+      }
+      default: assert( pStep->op==TK_SELECT ); {
+        SelectDest sDest;
+        Select *pSelect = sqlite3SelectDup(db, pStep->pSelect, 0);
+        sqlite3SelectDestInit(&sDest, SRT_Discard, 0);
+        sqlite3Select(pParse, pSelect, &sDest);
+        sqlite3SelectDelete(db, pSelect);
+        break;
+      }
+    }
+  }
+
+  return 0;
+}
+
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+/*
+** This function is used to add VdbeComment() annotations to a VDBE
+** program. It is not used in production code, only for debugging.
+*/
+static const char *onErrorText(int onError){
+  switch( onError ){
+    case OE_Abort:    return "abort";
+    case OE_Rollback: return "rollback";
+    case OE_Fail:     return "fail";
+    case OE_Replace:  return "replace";
+    case OE_Ignore:   return "ignore";
+    case OE_Default:  return "default";
+  }
+  return "n/a";
+}
+#endif
+
+/*
+** Parse context structure pFrom has just been used to create a sub-vdbe
+** (trigger program). If an error has occurred, transfer error information
+** from pFrom to pTo.
+*/
+static void transferParseError(Parse *pTo, Parse *pFrom){
+  assert( pFrom->zErrMsg==0 || pFrom->nErr );
+  assert( pTo->zErrMsg==0 || pTo->nErr );
+  if( pTo->nErr==0 ){
+    pTo->zErrMsg = pFrom->zErrMsg;
+    pTo->nErr = pFrom->nErr;
+    pTo->rc = pFrom->rc;
+  }else{
+    sqlite3DbFree(pFrom->db, pFrom->zErrMsg);
+  }
+}
+
+/*
+** Create and populate a new TriggerPrg object with a sub-program
+** implementing trigger pTrigger with ON CONFLICT policy orconf.
+*/
+static TriggerPrg *codeRowTrigger(
+  Parse *pParse,       /* Current parse context */
+  Trigger *pTrigger,   /* Trigger to code */
+  Table *pTab,         /* The table pTrigger is attached to */
+  int orconf           /* ON CONFLICT policy to code trigger program with */
+){
+  Parse *pTop = sqlite3ParseToplevel(pParse);
+  sqlite3 *db = pParse->db;   /* Database handle */
+  TriggerPrg *pPrg;           /* Value to return */
+  Expr *pWhen = 0;            /* Duplicate of trigger WHEN expression */
+  Vdbe *v;                    /* Temporary VM */
+  NameContext sNC;            /* Name context for sub-vdbe */
+  SubProgram *pProgram = 0;   /* Sub-vdbe for trigger program */
+  int iEndTrigger = 0;        /* Label to jump to if WHEN is false */
+  Parse sSubParse;            /* Parse context for sub-vdbe */
+
+  assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
+  assert( pTop->pVdbe );
+
+  /* Allocate the TriggerPrg and SubProgram objects. To ensure that they
+  ** are freed if an error occurs, link them into the Parse.pTriggerPrg
+  ** list of the top-level Parse object sooner rather than later.  */
+  pPrg = sqlite3DbMallocZero(db, sizeof(TriggerPrg));
+  if( !pPrg ) return 0;
+  pPrg->pNext = pTop->pTriggerPrg;
+  pTop->pTriggerPrg = pPrg;
+  pPrg->pProgram = pProgram = sqlite3DbMallocZero(db, sizeof(SubProgram));
+  if( !pProgram ) return 0;
+  sqlite3VdbeLinkSubProgram(pTop->pVdbe, pProgram);
+  pPrg->pTrigger = pTrigger;
+  pPrg->orconf = orconf;
+  pPrg->aColmask[0] = 0xffffffff;
+  pPrg->aColmask[1] = 0xffffffff;
+
+  /* Allocate and populate a new Parse context to use for coding the
+  ** trigger sub-program.  */
+  sqlite3ParseObjectInit(&sSubParse, db);
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = &sSubParse;
+  sSubParse.pTriggerTab = pTab;
+  sSubParse.pToplevel = pTop;
+  sSubParse.zAuthContext = pTrigger->zName;
+  sSubParse.eTriggerOp = pTrigger->op;
+  sSubParse.nQueryLoop = pParse->nQueryLoop;
+  sSubParse.prepFlags = pParse->prepFlags;
+
+  v = sqlite3GetVdbe(&sSubParse);
+  if( v ){
+    VdbeComment((v, "Start: %s.%s (%s %s%s%s ON %s)",
+      pTrigger->zName, onErrorText(orconf),
+      (pTrigger->tr_tm==TRIGGER_BEFORE ? "BEFORE" : "AFTER"),
+        (pTrigger->op==TK_UPDATE ? "UPDATE" : ""),
+        (pTrigger->op==TK_INSERT ? "INSERT" : ""),
+        (pTrigger->op==TK_DELETE ? "DELETE" : ""),
+      pTab->zName
+    ));
+#ifndef SQLITE_OMIT_TRACE
+    if( pTrigger->zName ){
+      sqlite3VdbeChangeP4(v, -1,
+        sqlite3MPrintf(db, "-- TRIGGER %s", pTrigger->zName), P4_DYNAMIC
+      );
+    }
+#endif
+
+    /* If one was specified, code the WHEN clause. If it evaluates to false
+    ** (or NULL) the sub-vdbe is immediately halted by jumping to the
+    ** OP_Halt inserted at the end of the program.  */
+    if( pTrigger->pWhen ){
+      pWhen = sqlite3ExprDup(db, pTrigger->pWhen, 0);
+      if( db->mallocFailed==0
+       && SQLITE_OK==sqlite3ResolveExprNames(&sNC, pWhen)
+      ){
+        iEndTrigger = sqlite3VdbeMakeLabel(&sSubParse);
+        sqlite3ExprIfFalse(&sSubParse, pWhen, iEndTrigger, SQLITE_JUMPIFNULL);
+      }
+      sqlite3ExprDelete(db, pWhen);
+    }
+
+    /* Code the trigger program into the sub-vdbe. */
+    codeTriggerProgram(&sSubParse, pTrigger->step_list, orconf);
+
+    /* Insert an OP_Halt at the end of the sub-program. */
+    if( iEndTrigger ){
+      sqlite3VdbeResolveLabel(v, iEndTrigger);
+    }
+    sqlite3VdbeAddOp0(v, OP_Halt);
+    VdbeComment((v, "End: %s.%s", pTrigger->zName, onErrorText(orconf)));
+    transferParseError(pParse, &sSubParse);
+
+    if( pParse->nErr==0 ){
+      assert( db->mallocFailed==0 );
+      pProgram->aOp = sqlite3VdbeTakeOpArray(v, &pProgram->nOp, &pTop->nMaxArg);
+    }
+    pProgram->nMem = sSubParse.nMem;
+    pProgram->nCsr = sSubParse.nTab;
+    pProgram->token = (void *)pTrigger;
+    pPrg->aColmask[0] = sSubParse.oldmask;
+    pPrg->aColmask[1] = sSubParse.newmask;
+    sqlite3VdbeDelete(v);
+  }else{
+    transferParseError(pParse, &sSubParse);
+  }
+
+  assert( !sSubParse.pTriggerPrg && !sSubParse.nMaxArg );
+  sqlite3ParseObjectReset(&sSubParse);
+  return pPrg;
+}
+
+/*
+** Return a pointer to a TriggerPrg object containing the sub-program for
+** trigger pTrigger with default ON CONFLICT algorithm orconf. If no such
+** TriggerPrg object exists, a new object is allocated and populated before
+** being returned.
+*/
+static TriggerPrg *getRowTrigger(
+  Parse *pParse,       /* Current parse context */
+  Trigger *pTrigger,   /* Trigger to code */
+  Table *pTab,         /* The table trigger pTrigger is attached to */
+  int orconf           /* ON CONFLICT algorithm. */
+){
+  Parse *pRoot = sqlite3ParseToplevel(pParse);
+  TriggerPrg *pPrg;
+
+  assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
+
+  /* It may be that this trigger has already been coded (or is in the
+  ** process of being coded). If this is the case, then an entry with
+  ** a matching TriggerPrg.pTrigger field will be present somewhere
+  ** in the Parse.pTriggerPrg list. Search for such an entry.  */
+  for(pPrg=pRoot->pTriggerPrg;
+      pPrg && (pPrg->pTrigger!=pTrigger || pPrg->orconf!=orconf);
+      pPrg=pPrg->pNext
+  );
+
+  /* If an existing TriggerPrg could not be located, create a new one. */
+  if( !pPrg ){
+    pPrg = codeRowTrigger(pParse, pTrigger, pTab, orconf);
+    pParse->db->errByteOffset = -1;
+  }
+
+  return pPrg;
+}
+
+/*
+** Generate code for the trigger program associated with trigger p on
+** table pTab. The reg, orconf and ignoreJump parameters passed to this
+** function are the same as those described in the header function for
+** sqlite3CodeRowTrigger()
+*/
+SQLITE_PRIVATE void sqlite3CodeRowTriggerDirect(
+  Parse *pParse,       /* Parse context */
+  Trigger *p,          /* Trigger to code */
+  Table *pTab,         /* The table to code triggers from */
+  int reg,             /* Reg array containing OLD.* and NEW.* values */
+  int orconf,          /* ON CONFLICT policy */
+  int ignoreJump       /* Instruction to jump to for RAISE(IGNORE) */
+){
+  Vdbe *v = sqlite3GetVdbe(pParse); /* Main VM */
+  TriggerPrg *pPrg;
+  pPrg = getRowTrigger(pParse, p, pTab, orconf);
+  assert( pPrg || pParse->nErr );
+
+  /* Code the OP_Program opcode in the parent VDBE. P4 of the OP_Program
+  ** is a pointer to the sub-vdbe containing the trigger program.  */
+  if( pPrg ){
+    int bRecursive = (p->zName && 0==(pParse->db->flags&SQLITE_RecTriggers));
+
+    sqlite3VdbeAddOp4(v, OP_Program, reg, ignoreJump, ++pParse->nMem,
+                      (const char *)pPrg->pProgram, P4_SUBPROGRAM);
+    VdbeComment(
+        (v, "Call: %s.%s", (p->zName?p->zName:"fkey"), onErrorText(orconf)));
+
+    /* Set the P5 operand of the OP_Program instruction to non-zero if
+    ** recursive invocation of this trigger program is disallowed. Recursive
+    ** invocation is disallowed if (a) the sub-program is really a trigger,
+    ** not a foreign key action, and (b) the flag to enable recursive triggers
+    ** is clear.  */
+    sqlite3VdbeChangeP5(v, (u16)bRecursive);
+  }
+}
+
+/*
+** This is called to code the required FOR EACH ROW triggers for an operation
+** on table pTab. The operation to code triggers for (INSERT, UPDATE or DELETE)
+** is given by the op parameter. The tr_tm parameter determines whether the
+** BEFORE or AFTER triggers are coded. If the operation is an UPDATE, then
+** parameter pChanges is passed the list of columns being modified.
+**
+** If there are no triggers that fire at the specified time for the specified
+** operation on pTab, this function is a no-op.
+**
+** The reg argument is the address of the first in an array of registers
+** that contain the values substituted for the new.* and old.* references
+** in the trigger program. If N is the number of columns in table pTab
+** (a copy of pTab->nCol), then registers are populated as follows:
+**
+**   Register       Contains
+**   ------------------------------------------------------
+**   reg+0          OLD.rowid
+**   reg+1          OLD.* value of left-most column of pTab
+**   ...            ...
+**   reg+N          OLD.* value of right-most column of pTab
+**   reg+N+1        NEW.rowid
+**   reg+N+2        NEW.* value of left-most column of pTab
+**   ...            ...
+**   reg+N+N+1      NEW.* value of right-most column of pTab
+**
+** For ON DELETE triggers, the registers containing the NEW.* values will
+** never be accessed by the trigger program, so they are not allocated or
+** populated by the caller (there is no data to populate them with anyway).
+** Similarly, for ON INSERT triggers the values stored in the OLD.* registers
+** are never accessed, and so are not allocated by the caller. So, for an
+** ON INSERT trigger, the value passed to this function as parameter reg
+** is not a readable register, although registers (reg+N) through
+** (reg+N+N+1) are.
+**
+** Parameter orconf is the default conflict resolution algorithm for the
+** trigger program to use (REPLACE, IGNORE etc.). Parameter ignoreJump
+** is the instruction that control should jump to if a trigger program
+** raises an IGNORE exception.
+*/
+SQLITE_PRIVATE void sqlite3CodeRowTrigger(
+  Parse *pParse,       /* Parse context */
+  Trigger *pTrigger,   /* List of triggers on table pTab */
+  int op,              /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
+  ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
+  int tr_tm,           /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
+  Table *pTab,         /* The table to code triggers from */
+  int reg,             /* The first in an array of registers (see above) */
+  int orconf,          /* ON CONFLICT policy */
+  int ignoreJump       /* Instruction to jump to for RAISE(IGNORE) */
+){
+  Trigger *p;          /* Used to iterate through pTrigger list */
+
+  assert( op==TK_UPDATE || op==TK_INSERT || op==TK_DELETE );
+  assert( tr_tm==TRIGGER_BEFORE || tr_tm==TRIGGER_AFTER );
+  assert( (op==TK_UPDATE)==(pChanges!=0) );
+
+  for(p=pTrigger; p; p=p->pNext){
+
+    /* Sanity checking:  The schema for the trigger and for the table are
+    ** always defined.  The trigger must be in the same schema as the table
+    ** or else it must be a TEMP trigger. */
+    assert( p->pSchema!=0 );
+    assert( p->pTabSchema!=0 );
+    assert( p->pSchema==p->pTabSchema
+         || p->pSchema==pParse->db->aDb[1].pSchema );
+
+    /* Determine whether we should code this trigger.  One of two choices:
+    **   1. The trigger is an exact match to the current DML statement
+    **   2. This is a RETURNING trigger for INSERT but we are currently
+    **      doing the UPDATE part of an UPSERT.
+    */
+    if( (p->op==op || (p->bReturning && p->op==TK_INSERT && op==TK_UPDATE))
+     && p->tr_tm==tr_tm
+     && checkColumnOverlap(p->pColumns, pChanges)
+    ){
+      if( !p->bReturning ){
+        sqlite3CodeRowTriggerDirect(pParse, p, pTab, reg, orconf, ignoreJump);
+      }else if( sqlite3IsToplevel(pParse) ){
+        codeReturningTrigger(pParse, p, pTab, reg);
+      }
+    }
+  }
+}
+
+/*
+** Triggers may access values stored in the old.* or new.* pseudo-table.
+** This function returns a 32-bit bitmask indicating which columns of the
+** old.* or new.* tables actually are used by triggers. This information
+** may be used by the caller, for example, to avoid having to load the entire
+** old.* record into memory when executing an UPDATE or DELETE command.
+**
+** Bit 0 of the returned mask is set if the left-most column of the
+** table may be accessed using an [old|new].<col> reference. Bit 1 is set if
+** the second leftmost column value is required, and so on. If there
+** are more than 32 columns in the table, and at least one of the columns
+** with an index greater than 32 may be accessed, 0xffffffff is returned.
+**
+** It is not possible to determine if the old.rowid or new.rowid column is
+** accessed by triggers. The caller must always assume that it is.
+**
+** Parameter isNew must be either 1 or 0. If it is 0, then the mask returned
+** applies to the old.* table. If 1, the new.* table.
+**
+** Parameter tr_tm must be a mask with one or both of the TRIGGER_BEFORE
+** and TRIGGER_AFTER bits set. Values accessed by BEFORE triggers are only
+** included in the returned mask if the TRIGGER_BEFORE bit is set in the
+** tr_tm parameter. Similarly, values accessed by AFTER triggers are only
+** included in the returned mask if the TRIGGER_AFTER bit is set in tr_tm.
+*/
+SQLITE_PRIVATE u32 sqlite3TriggerColmask(
+  Parse *pParse,       /* Parse context */
+  Trigger *pTrigger,   /* List of triggers on table pTab */
+  ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
+  int isNew,           /* 1 for new.* ref mask, 0 for old.* ref mask */
+  int tr_tm,           /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
+  Table *pTab,         /* The table to code triggers from */
+  int orconf           /* Default ON CONFLICT policy for trigger steps */
+){
+  const int op = pChanges ? TK_UPDATE : TK_DELETE;
+  u32 mask = 0;
+  Trigger *p;
+
+  assert( isNew==1 || isNew==0 );
+  if( IsView(pTab) ){
+    return 0xffffffff;
+  }
+  for(p=pTrigger; p; p=p->pNext){
+    if( p->op==op
+     && (tr_tm&p->tr_tm)
+     && checkColumnOverlap(p->pColumns,pChanges)
+    ){
+      if( p->bReturning ){
+        mask = 0xffffffff;
+      }else{
+        TriggerPrg *pPrg;
+        pPrg = getRowTrigger(pParse, p, pTab, orconf);
+        if( pPrg ){
+          mask |= pPrg->aColmask[isNew];
+        }
+      }
+    }
+  }
+
+  return mask;
+}
+
+#endif /* !defined(SQLITE_OMIT_TRIGGER) */
+
+/************** End of trigger.c *********************************************/
+/************** Begin file update.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle UPDATE statements.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Forward declaration */
+static void updateVirtualTable(
+  Parse *pParse,       /* The parsing context */
+  SrcList *pSrc,       /* The virtual table to be modified */
+  Table *pTab,         /* The virtual table */
+  ExprList *pChanges,  /* The columns to change in the UPDATE statement */
+  Expr *pRowidExpr,    /* Expression used to recompute the rowid */
+  int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
+  Expr *pWhere,        /* WHERE clause of the UPDATE statement */
+  int onError          /* ON CONFLICT strategy */
+);
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** The most recently coded instruction was an OP_Column to retrieve the
+** i-th column of table pTab. This routine sets the P4 parameter of the
+** OP_Column to the default value, if any.
+**
+** The default value of a column is specified by a DEFAULT clause in the
+** column definition. This was either supplied by the user when the table
+** was created, or added later to the table definition by an ALTER TABLE
+** command. If the latter, then the row-records in the table btree on disk
+** may not contain a value for the column and the default value, taken
+** from the P4 parameter of the OP_Column instruction, is returned instead.
+** If the former, then all row-records are guaranteed to include a value
+** for the column and the P4 value is not required.
+**
+** Column definitions created by an ALTER TABLE command may only have
+** literal default values specified: a number, null or a string. (If a more
+** complicated default expression value was provided, it is evaluated
+** when the ALTER TABLE is executed and one of the literal values written
+** into the sqlite_schema table.)
+**
+** Therefore, the P4 parameter is only required if the default value for
+** the column is a literal number, string or null. The sqlite3ValueFromExpr()
+** function is capable of transforming these types of expressions into
+** sqlite3_value objects.
+**
+** If column as REAL affinity and the table is an ordinary b-tree table
+** (not a virtual table) then the value might have been stored as an
+** integer.  In that case, add an OP_RealAffinity opcode to make sure
+** it has been converted into REAL.
+*/
+SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i, int iReg){
+  Column *pCol;
+  assert( pTab!=0 );
+  assert( pTab->nCol>i );
+  pCol = &pTab->aCol[i];
+  if( pCol->iDflt ){
+    sqlite3_value *pValue = 0;
+    u8 enc = ENC(sqlite3VdbeDb(v));
+    assert( !IsView(pTab) );
+    VdbeComment((v, "%s.%s", pTab->zName, pCol->zCnName));
+    assert( i<pTab->nCol );
+    sqlite3ValueFromExpr(sqlite3VdbeDb(v),
+                         sqlite3ColumnExpr(pTab,pCol), enc,
+                         pCol->affinity, &pValue);
+    if( pValue ){
+      sqlite3VdbeAppendP4(v, pValue, P4_MEM);
+    }
+  }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  if( pCol->affinity==SQLITE_AFF_REAL && !IsVirtual(pTab) ){
+    sqlite3VdbeAddOp1(v, OP_RealAffinity, iReg);
+  }
+#endif
+}
+
+/*
+** Check to see if column iCol of index pIdx references any of the
+** columns defined by aXRef and chngRowid.  Return true if it does
+** and false if not.  This is an optimization.  False-positives are a
+** performance degradation, but false-negatives can result in a corrupt
+** index and incorrect answers.
+**
+** aXRef[j] will be non-negative if column j of the original table is
+** being updated.  chngRowid will be true if the rowid of the table is
+** being updated.
+*/
+static int indexColumnIsBeingUpdated(
+  Index *pIdx,      /* The index to check */
+  int iCol,         /* Which column of the index to check */
+  int *aXRef,       /* aXRef[j]>=0 if column j is being updated */
+  int chngRowid     /* true if the rowid is being updated */
+){
+  i16 iIdxCol = pIdx->aiColumn[iCol];
+  assert( iIdxCol!=XN_ROWID ); /* Cannot index rowid */
+  if( iIdxCol>=0 ){
+    return aXRef[iIdxCol]>=0;
+  }
+  assert( iIdxCol==XN_EXPR );
+  assert( pIdx->aColExpr!=0 );
+  assert( pIdx->aColExpr->a[iCol].pExpr!=0 );
+  return sqlite3ExprReferencesUpdatedColumn(pIdx->aColExpr->a[iCol].pExpr,
+                                            aXRef,chngRowid);
+}
+
+/*
+** Check to see if index pIdx is a partial index whose conditional
+** expression might change values due to an UPDATE.  Return true if
+** the index is subject to change and false if the index is guaranteed
+** to be unchanged.  This is an optimization.  False-positives are a
+** performance degradation, but false-negatives can result in a corrupt
+** index and incorrect answers.
+**
+** aXRef[j] will be non-negative if column j of the original table is
+** being updated.  chngRowid will be true if the rowid of the table is
+** being updated.
+*/
+static int indexWhereClauseMightChange(
+  Index *pIdx,      /* The index to check */
+  int *aXRef,       /* aXRef[j]>=0 if column j is being updated */
+  int chngRowid     /* true if the rowid is being updated */
+){
+  if( pIdx->pPartIdxWhere==0 ) return 0;
+  return sqlite3ExprReferencesUpdatedColumn(pIdx->pPartIdxWhere,
+                                            aXRef, chngRowid);
+}
+
+/*
+** Allocate and return a pointer to an expression of type TK_ROW with
+** Expr.iColumn set to value (iCol+1). The resolver will modify the
+** expression to be a TK_COLUMN reading column iCol of the first
+** table in the source-list (pSrc->a[0]).
+*/
+static Expr *exprRowColumn(Parse *pParse, int iCol){
+  Expr *pRet = sqlite3PExpr(pParse, TK_ROW, 0, 0);
+  if( pRet ) pRet->iColumn = iCol+1;
+  return pRet;
+}
+
+/*
+** Assuming both the pLimit and pOrderBy parameters are NULL, this function
+** generates VM code to run the query:
+**
+**   SELECT <other-columns>, pChanges FROM pTabList WHERE pWhere
+**
+** and write the results to the ephemeral table already opened as cursor
+** iEph. None of pChanges, pTabList or pWhere are modified or consumed by
+** this function, they must be deleted by the caller.
+**
+** Or, if pLimit and pOrderBy are not NULL, and pTab is not a view:
+**
+**   SELECT <other-columns>, pChanges FROM pTabList
+**   WHERE pWhere
+**   GROUP BY <other-columns>
+**   ORDER BY pOrderBy LIMIT pLimit
+**
+** If pTab is a view, the GROUP BY clause is omitted.
+**
+** Exactly how results are written to table iEph, and exactly what
+** the <other-columns> in the query above are is determined by the type
+** of table pTabList->a[0].pTab.
+**
+** If the table is a WITHOUT ROWID table, then argument pPk must be its
+** PRIMARY KEY. In this case <other-columns> are the primary key columns
+** of the table, in order. The results of the query are written to ephemeral
+** table iEph as index keys, using OP_IdxInsert.
+**
+** If the table is actually a view, then <other-columns> are all columns of
+** the view. The results are written to the ephemeral table iEph as records
+** with automatically assigned integer keys.
+**
+** If the table is a virtual or ordinary intkey table, then <other-columns>
+** is its rowid. For a virtual table, the results are written to iEph as
+** records with automatically assigned integer keys For intkey tables, the
+** rowid value in <other-columns> is used as the integer key, and the
+** remaining fields make up the table record.
+*/
+static void updateFromSelect(
+  Parse *pParse,                  /* Parse context */
+  int iEph,                       /* Cursor for open eph. table */
+  Index *pPk,                     /* PK if table 0 is WITHOUT ROWID */
+  ExprList *pChanges,             /* List of expressions to return */
+  SrcList *pTabList,              /* List of tables to select from */
+  Expr *pWhere,                   /* WHERE clause for query */
+  ExprList *pOrderBy,             /* ORDER BY clause */
+  Expr *pLimit                    /* LIMIT clause */
+){
+  int i;
+  SelectDest dest;
+  Select *pSelect = 0;
+  ExprList *pList = 0;
+  ExprList *pGrp = 0;
+  Expr *pLimit2 = 0;
+  ExprList *pOrderBy2 = 0;
+  sqlite3 *db = pParse->db;
+  Table *pTab = pTabList->a[0].pSTab;
+  SrcList *pSrc;
+  Expr *pWhere2;
+  int eDest;
+
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( pOrderBy && pLimit==0 ) {
+    sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on UPDATE");
+    return;
+  }
+  pOrderBy2 = sqlite3ExprListDup(db, pOrderBy, 0);
+  pLimit2 = sqlite3ExprDup(db, pLimit, 0);
+#else
+  UNUSED_PARAMETER(pOrderBy);
+  UNUSED_PARAMETER(pLimit);
+#endif
+
+  pSrc = sqlite3SrcListDup(db, pTabList, 0);
+  pWhere2 = sqlite3ExprDup(db, pWhere, 0);
+
+  assert( pTabList->nSrc>1 );
+  if( pSrc ){
+    assert( pSrc->a[0].fg.notCte );
+    pSrc->a[0].iCursor = -1;
+    pSrc->a[0].pSTab->nTabRef--;
+    pSrc->a[0].pSTab = 0;
+  }
+  if( pPk ){
+    for(i=0; i<pPk->nKeyCol; i++){
+      Expr *pNew = exprRowColumn(pParse, pPk->aiColumn[i]);
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+      if( pLimit ){
+        pGrp = sqlite3ExprListAppend(pParse, pGrp, sqlite3ExprDup(db, pNew, 0));
+      }
+#endif
+      pList = sqlite3ExprListAppend(pParse, pList, pNew);
+    }
+    eDest = IsVirtual(pTab) ? SRT_Table : SRT_Upfrom;
+  }else if( IsView(pTab) ){
+    for(i=0; i<pTab->nCol; i++){
+      pList = sqlite3ExprListAppend(pParse, pList, exprRowColumn(pParse, i));
+    }
+    eDest = SRT_Table;
+  }else{
+    eDest = IsVirtual(pTab) ? SRT_Table : SRT_Upfrom;
+    pList = sqlite3ExprListAppend(pParse, 0, sqlite3PExpr(pParse,TK_ROW,0,0));
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+    if( pLimit ){
+      pGrp = sqlite3ExprListAppend(pParse, 0, sqlite3PExpr(pParse,TK_ROW,0,0));
+    }
+#endif
+  }
+  assert( pChanges!=0 || pParse->db->mallocFailed );
+  if( pChanges ){
+    for(i=0; i<pChanges->nExpr; i++){
+      pList = sqlite3ExprListAppend(pParse, pList,
+          sqlite3ExprDup(db, pChanges->a[i].pExpr, 0)
+      );
+    }
+  }
+  pSelect = sqlite3SelectNew(pParse, pList,
+      pSrc, pWhere2, pGrp, 0, pOrderBy2,
+      SF_UFSrcCheck|SF_IncludeHidden|SF_UpdateFrom, pLimit2
+  );
+  if( pSelect ) pSelect->selFlags |= SF_OrderByReqd;
+  sqlite3SelectDestInit(&dest, eDest, iEph);
+  dest.iSDParm2 = (pPk ? pPk->nKeyCol : -1);
+  sqlite3Select(pParse, pSelect, &dest);
+  sqlite3SelectDelete(db, pSelect);
+}
+
+/*
+** Process an UPDATE statement.
+**
+**   UPDATE OR IGNORE tbl SET a=b, c=d FROM tbl2... WHERE e<5 AND f NOT NULL;
+**          \_______/ \_/     \______/      \_____/       \________________/
+**           onError   |      pChanges         |                pWhere
+**                     \_______________________/
+**                               pTabList
+*/
+SQLITE_PRIVATE void sqlite3Update(
+  Parse *pParse,         /* The parser context */
+  SrcList *pTabList,     /* The table in which we should change things */
+  ExprList *pChanges,    /* Things to be changed */
+  Expr *pWhere,          /* The WHERE clause.  May be null */
+  int onError,           /* How to handle constraint errors */
+  ExprList *pOrderBy,    /* ORDER BY clause. May be null */
+  Expr *pLimit,          /* LIMIT clause. May be null */
+  Upsert *pUpsert        /* ON CONFLICT clause, or null */
+){
+  int i, j, k;           /* Loop counters */
+  Table *pTab;           /* The table to be updated */
+  int addrTop = 0;       /* VDBE instruction address of the start of the loop */
+  WhereInfo *pWInfo = 0; /* Information about the WHERE clause */
+  Vdbe *v;               /* The virtual database engine */
+  Index *pIdx;           /* For looping over indices */
+  Index *pPk;            /* The PRIMARY KEY index for WITHOUT ROWID tables */
+  int nIdx;              /* Number of indices that need updating */
+  int nAllIdx;           /* Total number of indexes */
+  int iBaseCur;          /* Base cursor number */
+  int iDataCur;          /* Cursor for the canonical data btree */
+  int iIdxCur;           /* Cursor for the first index */
+  sqlite3 *db;           /* The database structure */
+  int *aRegIdx = 0;      /* Registers for to each index and the main table */
+  int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
+                         ** an expression for the i-th column of the table.
+                         ** aXRef[i]==-1 if the i-th column is not changed. */
+  u8 *aToOpen;           /* 1 for tables and indices to be opened */
+  u8 chngPk;             /* PRIMARY KEY changed in a WITHOUT ROWID table */
+  u8 chngRowid;          /* Rowid changed in a normal table */
+  u8 chngKey;            /* Either chngPk or chngRowid */
+  Expr *pRowidExpr = 0;  /* Expression defining the new record number */
+  int iRowidExpr = -1;   /* Index of "rowid=" (or IPK) assignment in pChanges */
+  AuthContext sContext;  /* The authorization context */
+  NameContext sNC;       /* The name-context to resolve expressions in */
+  int iDb;               /* Database containing the table being updated */
+  int eOnePass;          /* ONEPASS_XXX value from where.c */
+  int hasFK;             /* True if foreign key processing is required */
+  int labelBreak;        /* Jump here to break out of UPDATE loop */
+  int labelContinue;     /* Jump here to continue next step of UPDATE loop */
+  int flags;             /* Flags for sqlite3WhereBegin() */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;            /* True when updating a view (INSTEAD OF trigger) */
+  Trigger *pTrigger;     /* List of triggers on pTab, if required */
+  int tmask;             /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
+#endif
+  int newmask;           /* Mask of NEW.* columns accessed by BEFORE triggers */
+  int iEph = 0;          /* Ephemeral table holding all primary key values */
+  int nKey = 0;          /* Number of elements in regKey for WITHOUT ROWID */
+  int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */
+  int addrOpen = 0;      /* Address of OP_OpenEphemeral */
+  int iPk = 0;           /* First of nPk cells holding PRIMARY KEY value */
+  i16 nPk = 0;           /* Number of components of the PRIMARY KEY */
+  int bReplace = 0;      /* True if REPLACE conflict resolution might happen */
+  int bFinishSeek = 1;   /* The OP_FinishSeek opcode is needed */
+  int nChangeFrom = 0;   /* If there is a FROM, pChanges->nExpr, else 0 */
+
+  /* Register Allocations */
+  int regRowCount = 0;   /* A count of rows changed */
+  int regOldRowid = 0;   /* The old rowid */
+  int regNewRowid = 0;   /* The new rowid */
+  int regNew = 0;        /* Content of the NEW.* table in triggers */
+  int regOld = 0;        /* Content of OLD.* table in triggers */
+  int regRowSet = 0;     /* Rowset of rows to be updated */
+  int regKey = 0;        /* composite PRIMARY KEY value */
+
+  memset(&sContext, 0, sizeof(sContext));
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nErr ){
+    goto update_cleanup;
+  }
+  assert( db->mallocFailed==0 );
+
+  /* Locate the table which we want to update.
+  */
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 ) goto update_cleanup;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+
+  /* Figure out if we have any triggers and if the table being
+  ** updated is a view.
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges, &tmask);
+  isView = IsView(pTab);
+  assert( pTrigger || tmask==0 );
+#else
+# define pTrigger 0
+# define isView 0
+# define tmask 0
+#endif
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x10000 ){
+    sqlite3TreeViewLine(0, "In sqlite3Update() at %s:%d", __FILE__, __LINE__);
+    sqlite3TreeViewUpdate(pParse->pWith, pTabList, pChanges, pWhere,
+                          onError, pOrderBy, pLimit, pUpsert, pTrigger);
+  }
+#endif
+
+  /* If there was a FROM clause, set nChangeFrom to the number of expressions
+  ** in the change-list. Otherwise, set it to 0. There cannot be a FROM
+  ** clause if this function is being called to generate code for part of
+  ** an UPSERT statement.  */
+  nChangeFrom = (pTabList->nSrc>1) ? pChanges->nExpr : 0;
+  assert( nChangeFrom==0 || pUpsert==0 );
+
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( !isView && nChangeFrom==0 ){
+    pWhere = sqlite3LimitWhere(
+        pParse, pTabList, pWhere, pOrderBy, pLimit, "UPDATE"
+    );
+    pOrderBy = 0;
+    pLimit = 0;
+  }
+#endif
+
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto update_cleanup;
+  }
+  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
+    goto update_cleanup;
+  }
+
+  /* Allocate a cursors for the main database table and for all indices.
+  ** The index cursors might not be used, but if they are used they
+  ** need to occur right after the database cursor.  So go ahead and
+  ** allocate enough space, just in case.
+  */
+  iBaseCur = iDataCur = pParse->nTab++;
+  iIdxCur = iDataCur+1;
+  pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
+  testcase( pPk!=0 && pPk!=pTab->pIndex );
+  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
+    if( pPk==pIdx ){
+      iDataCur = pParse->nTab;
+    }
+    pParse->nTab++;
+  }
+  if( pUpsert ){
+    /* On an UPSERT, reuse the same cursors already opened by INSERT */
+    iDataCur = pUpsert->iDataCur;
+    iIdxCur = pUpsert->iIdxCur;
+    pParse->nTab = iBaseCur;
+  }
+  pTabList->a[0].iCursor = iDataCur;
+
+  /* Allocate space for aXRef[], aRegIdx[], and aToOpen[].
+  ** Initialize aXRef[] and aToOpen[] to their default values.
+  */
+  aXRef = sqlite3DbMallocRawNN(db, sizeof(int) * (pTab->nCol+nIdx+1) + nIdx+2 );
+  if( aXRef==0 ) goto update_cleanup;
+  aRegIdx = aXRef+pTab->nCol;
+  aToOpen = (u8*)(aRegIdx+nIdx+1);
+  memset(aToOpen, 1, nIdx+1);
+  aToOpen[nIdx+1] = 0;
+  for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
+
+  /* Initialize the name-context */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  sNC.pSrcList = pTabList;
+  sNC.uNC.pUpsert = pUpsert;
+  sNC.ncFlags = NC_UUpsert;
+
+  /* Begin generating code. */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) goto update_cleanup;
+
+  /* Resolve the column names in all the expressions of the
+  ** of the UPDATE statement.  Also find the column index
+  ** for each column to be updated in the pChanges array.  For each
+  ** column to be updated, make sure we have authorization to change
+  ** that column.
+  */
+  chngRowid = chngPk = 0;
+  for(i=0; i<pChanges->nExpr; i++){
+    u8 hCol = sqlite3StrIHash(pChanges->a[i].zEName);
+    /* If this is an UPDATE with a FROM clause, do not resolve expressions
+    ** here. The call to sqlite3Select() below will do that. */
+    if( nChangeFrom==0 && sqlite3ResolveExprNames(&sNC, pChanges->a[i].pExpr) ){
+      goto update_cleanup;
+    }
+    for(j=0; j<pTab->nCol; j++){
+      if( pTab->aCol[j].hName==hCol
+       && sqlite3StrICmp(pTab->aCol[j].zCnName, pChanges->a[i].zEName)==0
+      ){
+        if( j==pTab->iPKey ){
+          chngRowid = 1;
+          pRowidExpr = pChanges->a[i].pExpr;
+          iRowidExpr = i;
+        }else if( pPk && (pTab->aCol[j].colFlags & COLFLAG_PRIMKEY)!=0 ){
+          chngPk = 1;
+        }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+        else if( pTab->aCol[j].colFlags & COLFLAG_GENERATED ){
+          testcase( pTab->aCol[j].colFlags & COLFLAG_VIRTUAL );
+          testcase( pTab->aCol[j].colFlags & COLFLAG_STORED );
+          sqlite3ErrorMsg(pParse,
+             "cannot UPDATE generated column \"%s\"",
+             pTab->aCol[j].zCnName);
+          goto update_cleanup;
+        }
+#endif
+        aXRef[j] = i;
+        break;
+      }
+    }
+    if( j>=pTab->nCol ){
+      if( pPk==0 && sqlite3IsRowid(pChanges->a[i].zEName) ){
+        j = -1;
+        chngRowid = 1;
+        pRowidExpr = pChanges->a[i].pExpr;
+        iRowidExpr = i;
+      }else{
+        sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zEName);
+        pParse->checkSchema = 1;
+        goto update_cleanup;
+      }
+    }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    {
+      int rc;
+      rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
+                            j<0 ? "ROWID" : pTab->aCol[j].zCnName,
+                            db->aDb[iDb].zDbSName);
+      if( rc==SQLITE_DENY ){
+        goto update_cleanup;
+      }else if( rc==SQLITE_IGNORE ){
+        aXRef[j] = -1;
+      }
+    }
+#endif
+  }
+  assert( (chngRowid & chngPk)==0 );
+  assert( chngRowid==0 || chngRowid==1 );
+  assert( chngPk==0 || chngPk==1 );
+  chngKey = chngRowid + chngPk;
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  /* Mark generated columns as changing if their generator expressions
+  ** reference any changing column.  The actual aXRef[] value for
+  ** generated expressions is not used, other than to check to see that it
+  ** is non-negative, so the value of aXRef[] for generated columns can be
+  ** set to any non-negative number.  We use 99999 so that the value is
+  ** obvious when looking at aXRef[] in a symbolic debugger.
+  */
+  if( pTab->tabFlags & TF_HasGenerated ){
+    int bProgress;
+    testcase( pTab->tabFlags & TF_HasVirtual );
+    testcase( pTab->tabFlags & TF_HasStored );
+    do{
+      bProgress = 0;
+      for(i=0; i<pTab->nCol; i++){
+        if( aXRef[i]>=0 ) continue;
+        if( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)==0 ) continue;
+        if( sqlite3ExprReferencesUpdatedColumn(
+                sqlite3ColumnExpr(pTab, &pTab->aCol[i]),
+                 aXRef, chngRowid)
+        ){
+          aXRef[i] = 99999;
+          bProgress = 1;
+        }
+      }
+    }while( bProgress );
+  }
+#endif
+
+  /* The SET expressions are not actually used inside the WHERE loop.
+  ** So reset the colUsed mask. Unless this is a virtual table. In that
+  ** case, set all bits of the colUsed mask (to ensure that the virtual
+  ** table implementation makes all columns available).
+  */
+  pTabList->a[0].colUsed = IsVirtual(pTab) ? ALLBITS : 0;
+
+  hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngKey);
+
+  /* There is one entry in the aRegIdx[] array for each index on the table
+  ** being updated.  Fill in aRegIdx[] with a register number that will hold
+  ** the key for accessing each index.
+  */
+  if( onError==OE_Replace ) bReplace = 1;
+  for(nAllIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nAllIdx++){
+    int reg;
+    if( chngKey || hasFK>1 || pIdx==pPk
+     || indexWhereClauseMightChange(pIdx,aXRef,chngRowid)
+    ){
+      reg = ++pParse->nMem;
+      pParse->nMem += pIdx->nColumn;
+    }else{
+      reg = 0;
+      for(i=0; i<pIdx->nKeyCol; i++){
+        if( indexColumnIsBeingUpdated(pIdx, i, aXRef, chngRowid) ){
+          reg = ++pParse->nMem;
+          pParse->nMem += pIdx->nColumn;
+          if( onError==OE_Default && pIdx->onError==OE_Replace ){
+            bReplace = 1;
+          }
+          break;
+        }
+      }
+    }
+    if( reg==0 ) aToOpen[nAllIdx+1] = 0;
+    aRegIdx[nAllIdx] = reg;
+  }
+  aRegIdx[nAllIdx] = ++pParse->nMem;  /* Register storing the table record */
+  if( bReplace ){
+    /* If REPLACE conflict resolution might be invoked, open cursors on all
+    ** indexes in case they are needed to delete records.  */
+    memset(aToOpen, 1, nIdx+1);
+  }
+
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, pTrigger || hasFK, iDb);
+
+  /* Allocate required registers. */
+  if( !IsVirtual(pTab) ){
+    /* For now, regRowSet and aRegIdx[nAllIdx] share the same register.
+    ** If regRowSet turns out to be needed, then aRegIdx[nAllIdx] will be
+    ** reallocated.  aRegIdx[nAllIdx] is the register in which the main
+    ** table record is written.  regRowSet holds the RowSet for the
+    ** two-pass update algorithm. */
+    assert( aRegIdx[nAllIdx]==pParse->nMem );
+    regRowSet = aRegIdx[nAllIdx];
+    regOldRowid = regNewRowid = ++pParse->nMem;
+    if( chngPk || pTrigger || hasFK ){
+      regOld = pParse->nMem + 1;
+      pParse->nMem += pTab->nCol;
+    }
+    if( chngKey || pTrigger || hasFK ){
+      regNewRowid = ++pParse->nMem;
+    }
+    regNew = pParse->nMem + 1;
+    pParse->nMem += pTab->nCol;
+  }
+
+  /* Start the view context. */
+  if( isView ){
+    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
+  }
+
+  /* If we are trying to update a view, realize that view into
+  ** an ephemeral table.
+  */
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+  if( nChangeFrom==0 && isView ){
+    sqlite3MaterializeView(pParse, pTab,
+        pWhere, pOrderBy, pLimit, iDataCur
+    );
+    pOrderBy = 0;
+    pLimit = 0;
+  }
+#endif
+
+  /* Resolve the column names in all the expressions in the
+  ** WHERE clause.
+  */
+  if( nChangeFrom==0 && sqlite3ResolveExprNames(&sNC, pWhere) ){
+    goto update_cleanup;
+  }
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  /* Virtual tables must be handled separately */
+  if( IsVirtual(pTab) ){
+    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
+                       pWhere, onError);
+    goto update_cleanup;
+  }
+#endif
+
+  /* Jump to labelBreak to abandon further processing of this UPDATE */
+  labelContinue = labelBreak = sqlite3VdbeMakeLabel(pParse);
+
+  /* Not an UPSERT.  Normal processing.  Begin by
+  ** initialize the count of updated rows */
+  if( (db->flags&SQLITE_CountRows)!=0
+   && !pParse->pTriggerTab
+   && !pParse->nested
+   && !pParse->bReturning
+   && pUpsert==0
+  ){
+    regRowCount = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
+  }
+
+  if( nChangeFrom==0 && HasRowid(pTab) ){
+    sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
+    iEph = pParse->nTab++;
+    addrOpen = sqlite3VdbeAddOp3(v, OP_OpenEphemeral, iEph, 0, regRowSet);
+  }else{
+    assert( pPk!=0 || HasRowid(pTab) );
+    nPk = pPk ? pPk->nKeyCol : 0;
+    iPk = pParse->nMem+1;
+    pParse->nMem += nPk;
+    pParse->nMem += nChangeFrom;
+    regKey = ++pParse->nMem;
+    if( pUpsert==0 ){
+      int nEphCol = nPk + nChangeFrom + (isView ? pTab->nCol : 0);
+      iEph = pParse->nTab++;
+      if( pPk ) sqlite3VdbeAddOp3(v, OP_Null, 0, iPk, iPk+nPk-1);
+      addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nEphCol);
+      if( pPk ){
+        KeyInfo *pKeyInfo = sqlite3KeyInfoOfIndex(pParse, pPk);
+        if( pKeyInfo ){
+          pKeyInfo->nAllField = nEphCol;
+          sqlite3VdbeAppendP4(v, pKeyInfo, P4_KEYINFO);
+        }
+      }
+      if( nChangeFrom ){
+        updateFromSelect(
+            pParse, iEph, pPk, pChanges, pTabList, pWhere, pOrderBy, pLimit
+        );
+#ifndef SQLITE_OMIT_SUBQUERY
+        if( isView ) iDataCur = iEph;
+#endif
+      }
+    }
+  }
+
+  if( nChangeFrom ){
+    sqlite3MultiWrite(pParse);
+    eOnePass = ONEPASS_OFF;
+    nKey = nPk;
+    regKey = iPk;
+  }else{
+    if( pUpsert ){
+      /* If this is an UPSERT, then all cursors have already been opened by
+      ** the outer INSERT and the data cursor should be pointing at the row
+      ** that is to be updated.  So bypass the code that searches for the
+      ** row(s) to be updated.
+      */
+      pWInfo = 0;
+      eOnePass = ONEPASS_SINGLE;
+      sqlite3ExprIfFalse(pParse, pWhere, labelBreak, SQLITE_JUMPIFNULL);
+      bFinishSeek = 0;
+    }else{
+      /* Begin the database scan.
+      **
+      ** Do not consider a single-pass strategy for a multi-row update if
+      ** there is anything that might disrupt the cursor being used to do
+      ** the UPDATE:
+      **   (1) This is a nested UPDATE
+      **   (2) There are triggers
+      **   (3) There are FOREIGN KEY constraints
+      **   (4) There are REPLACE conflict handlers
+      **   (5) There are subqueries in the WHERE clause
+      */
+      flags = WHERE_ONEPASS_DESIRED;
+      if( !pParse->nested
+       && !pTrigger
+       && !hasFK
+       && !chngKey
+       && !bReplace
+       && (pWhere==0 || !ExprHasProperty(pWhere, EP_Subquery))
+      ){
+        flags |= WHERE_ONEPASS_MULTIROW;
+      }
+      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere,0,0,0,flags,iIdxCur);
+      if( pWInfo==0 ) goto update_cleanup;
+
+      /* A one-pass strategy that might update more than one row may not
+      ** be used if any column of the index used for the scan is being
+      ** updated. Otherwise, if there is an index on "b", statements like
+      ** the following could create an infinite loop:
+      **
+      **   UPDATE t1 SET b=b+1 WHERE b>?
+      **
+      ** Fall back to ONEPASS_OFF if where.c has selected a ONEPASS_MULTI
+      ** strategy that uses an index for which one or more columns are being
+      ** updated.  */
+      eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
+      bFinishSeek = sqlite3WhereUsesDeferredSeek(pWInfo);
+      if( eOnePass!=ONEPASS_SINGLE ){
+        sqlite3MultiWrite(pParse);
+        if( eOnePass==ONEPASS_MULTI ){
+          int iCur = aiCurOnePass[1];
+          if( iCur>=0 && iCur!=iDataCur && aToOpen[iCur-iBaseCur] ){
+            eOnePass = ONEPASS_OFF;
+          }
+          assert( iCur!=iDataCur || !HasRowid(pTab) );
+        }
+      }
+    }
+
+    if( HasRowid(pTab) ){
+      /* Read the rowid of the current row of the WHERE scan. In ONEPASS_OFF
+      ** mode, write the rowid into the FIFO. In either of the one-pass modes,
+      ** leave it in register regOldRowid.  */
+      sqlite3VdbeAddOp2(v, OP_Rowid, iDataCur, regOldRowid);
+      if( eOnePass==ONEPASS_OFF ){
+        aRegIdx[nAllIdx] = ++pParse->nMem;
+        sqlite3VdbeAddOp3(v, OP_Insert, iEph, regRowSet, regOldRowid);
+      }else{
+        if( ALWAYS(addrOpen) ) sqlite3VdbeChangeToNoop(v, addrOpen);
+      }
+    }else{
+      /* Read the PK of the current row into an array of registers. In
+      ** ONEPASS_OFF mode, serialize the array into a record and store it in
+      ** the ephemeral table. Or, in ONEPASS_SINGLE or MULTI mode, change
+      ** the OP_OpenEphemeral instruction to a Noop (the ephemeral table
+      ** is not required) and leave the PK fields in the array of registers.  */
+      for(i=0; i<nPk; i++){
+        assert( pPk->aiColumn[i]>=0 );
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur,
+                                        pPk->aiColumn[i], iPk+i);
+      }
+      if( eOnePass ){
+        if( addrOpen ) sqlite3VdbeChangeToNoop(v, addrOpen);
+        nKey = nPk;
+        regKey = iPk;
+      }else{
+        sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, regKey,
+                          sqlite3IndexAffinityStr(db, pPk), nPk);
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEph, regKey, iPk, nPk);
+      }
+    }
+  }
+
+  if( pUpsert==0 ){
+    if( nChangeFrom==0 && eOnePass!=ONEPASS_MULTI ){
+      sqlite3WhereEnd(pWInfo);
+    }
+
+    if( !isView ){
+      int addrOnce = 0;
+      int iNotUsed1 = 0;
+      int iNotUsed2 = 0;
+
+      /* Open every index that needs updating. */
+      if( eOnePass!=ONEPASS_OFF ){
+        if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iBaseCur] = 0;
+        if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iBaseCur] = 0;
+      }
+
+      if( eOnePass==ONEPASS_MULTI && (nIdx-(aiCurOnePass[1]>=0))>0 ){
+        addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+      }
+      sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, iBaseCur,
+                                 aToOpen, &iNotUsed1, &iNotUsed2);
+      if( addrOnce ){
+        sqlite3VdbeJumpHereOrPopInst(v, addrOnce);
+      }
+    }
+
+    /* Top of the update loop */
+    if( eOnePass!=ONEPASS_OFF ){
+      if( aiCurOnePass[0]!=iDataCur
+       && aiCurOnePass[1]!=iDataCur
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+       && !isView
+#endif
+      ){
+        assert( pPk );
+        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey,nKey);
+        VdbeCoverage(v);
+      }
+      if( eOnePass!=ONEPASS_SINGLE ){
+        labelContinue = sqlite3VdbeMakeLabel(pParse);
+      }
+      sqlite3VdbeAddOp2(v, OP_IsNull, pPk ? regKey : regOldRowid, labelBreak);
+      VdbeCoverageIf(v, pPk==0);
+      VdbeCoverageIf(v, pPk!=0);
+    }else if( pPk || nChangeFrom ){
+      labelContinue = sqlite3VdbeMakeLabel(pParse);
+      sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak); VdbeCoverage(v);
+      addrTop = sqlite3VdbeCurrentAddr(v);
+      if( nChangeFrom ){
+        if( !isView ){
+          if( pPk ){
+            for(i=0; i<nPk; i++){
+              sqlite3VdbeAddOp3(v, OP_Column, iEph, i, iPk+i);
+            }
+            sqlite3VdbeAddOp4Int(
+                v, OP_NotFound, iDataCur, labelContinue, iPk, nPk
+            ); VdbeCoverage(v);
+          }else{
+            sqlite3VdbeAddOp2(v, OP_Rowid, iEph, regOldRowid);
+            sqlite3VdbeAddOp3(
+                v, OP_NotExists, iDataCur, labelContinue, regOldRowid
+            ); VdbeCoverage(v);
+          }
+        }
+      }else{
+        sqlite3VdbeAddOp2(v, OP_RowData, iEph, regKey);
+        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelContinue, regKey,0);
+        VdbeCoverage(v);
+      }
+    }else{
+      sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak); VdbeCoverage(v);
+      labelContinue = sqlite3VdbeMakeLabel(pParse);
+      addrTop = sqlite3VdbeAddOp2(v, OP_Rowid, iEph, regOldRowid);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue, regOldRowid);
+      VdbeCoverage(v);
+    }
+  }
+
+  /* If the rowid value will change, set register regNewRowid to
+  ** contain the new value. If the rowid is not being modified,
+  ** then regNewRowid is the same register as regOldRowid, which is
+  ** already populated.  */
+  assert( chngKey || pTrigger || hasFK || regOldRowid==regNewRowid );
+  if( chngRowid ){
+    assert( iRowidExpr>=0 );
+    if( nChangeFrom==0 ){
+      sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_Column, iEph, iRowidExpr, regNewRowid);
+    }
+    sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid); VdbeCoverage(v);
+  }
+
+  /* Compute the old pre-UPDATE content of the row being changed, if that
+  ** information is needed */
+  if( chngPk || hasFK || pTrigger ){
+    u32 oldmask = (hasFK ? sqlite3FkOldmask(pParse, pTab) : 0);
+    oldmask |= sqlite3TriggerColmask(pParse,
+        pTrigger, pChanges, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onError
+    );
+    for(i=0; i<pTab->nCol; i++){
+      u32 colFlags = pTab->aCol[i].colFlags;
+      k = sqlite3TableColumnToStorage(pTab, i) + regOld;
+      if( oldmask==0xffffffff
+       || (i<32 && (oldmask & MASKBIT32(i))!=0)
+       || (colFlags & COLFLAG_PRIMKEY)!=0
+      ){
+        testcase(  oldmask!=0xffffffff && i==31 );
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, k);
+      }
+    }
+    if( chngRowid==0 && pPk==0 ){
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+      if( isView ) sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
+#endif
+      sqlite3VdbeAddOp2(v, OP_Copy, regOldRowid, regNewRowid);
+    }
+  }
+
+  /* Populate the array of registers beginning at regNew with the new
+  ** row data. This array is used to check constants, create the new
+  ** table and index records, and as the values for any new.* references
+  ** made by triggers.
+  **
+  ** If there are one or more BEFORE triggers, then do not populate the
+  ** registers associated with columns that are (a) not modified by
+  ** this UPDATE statement and (b) not accessed by new.* references. The
+  ** values for registers not modified by the UPDATE must be reloaded from
+  ** the database after the BEFORE triggers are fired anyway (as the trigger
+  ** may have modified them). So not loading those that are not going to
+  ** be used eliminates some redundant opcodes.
+  */
+  newmask = sqlite3TriggerColmask(
+      pParse, pTrigger, pChanges, 1, TRIGGER_BEFORE, pTab, onError
+  );
+  for(i=0, k=regNew; i<pTab->nCol; i++, k++){
+    if( i==pTab->iPKey ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, k);
+    }else if( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)!=0 ){
+      if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ) k--;
+    }else{
+      j = aXRef[i];
+      if( j>=0 ){
+        if( nChangeFrom ){
+          int nOff = (isView ? pTab->nCol : nPk);
+          assert( eOnePass==ONEPASS_OFF );
+          sqlite3VdbeAddOp3(v, OP_Column, iEph, nOff+j, k);
+        }else{
+          sqlite3ExprCode(pParse, pChanges->a[j].pExpr, k);
+        }
+      }else if( 0==(tmask&TRIGGER_BEFORE) || i>31 || (newmask & MASKBIT32(i)) ){
+        /* This branch loads the value of a column that will not be changed
+        ** into a register. This is done if there are no BEFORE triggers, or
+        ** if there are one or more BEFORE triggers that use this value via
+        ** a new.* reference in a trigger program.
+        */
+        testcase( i==31 );
+        testcase( i==32 );
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
+        bFinishSeek = 0;
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, k);
+      }
+    }
+  }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  if( pTab->tabFlags & TF_HasGenerated ){
+    testcase( pTab->tabFlags & TF_HasVirtual );
+    testcase( pTab->tabFlags & TF_HasStored );
+    sqlite3ComputeGeneratedColumns(pParse, regNew, pTab);
+  }
+#endif
+
+  /* Fire any BEFORE UPDATE triggers. This happens before constraints are
+  ** verified. One could argue that this is wrong.
+  */
+  if( tmask&TRIGGER_BEFORE ){
+    sqlite3TableAffinity(v, pTab, regNew);
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
+        TRIGGER_BEFORE, pTab, regOldRowid, onError, labelContinue);
+
+    if( !isView ){
+      /* The row-trigger may have deleted the row being updated. In this
+      ** case, jump to the next row. No updates or AFTER triggers are
+      ** required. This behavior - what happens when the row being updated
+      ** is deleted or renamed by a BEFORE trigger - is left undefined in the
+      ** documentation.
+      */
+      if( pPk ){
+        sqlite3VdbeAddOp4Int(v, OP_NotFound,iDataCur,labelContinue,regKey,nKey);
+        VdbeCoverage(v);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue,regOldRowid);
+        VdbeCoverage(v);
+      }
+
+      /* After-BEFORE-trigger-reload-loop:
+      ** If it did not delete it, the BEFORE trigger may still have modified
+      ** some of the columns of the row being updated. Load the values for
+      ** all columns not modified by the update statement into their registers
+      ** in case this has happened. Only unmodified columns are reloaded.
+      ** The values computed for modified columns use the values before the
+      ** BEFORE trigger runs.  See test case trigger1-18.0 (added 2018-04-26)
+      ** for an example.
+      */
+      for(i=0, k=regNew; i<pTab->nCol; i++, k++){
+        if( pTab->aCol[i].colFlags & COLFLAG_GENERATED ){
+          if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ) k--;
+        }else if( aXRef[i]<0 && i!=pTab->iPKey ){
+          sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
+        }
+      }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+      if( pTab->tabFlags & TF_HasGenerated ){
+        testcase( pTab->tabFlags & TF_HasVirtual );
+        testcase( pTab->tabFlags & TF_HasStored );
+        sqlite3ComputeGeneratedColumns(pParse, regNew, pTab);
+      }
+#endif
+    }
+  }
+
+  if( !isView ){
+    /* Do constraint checks. */
+    assert( regOldRowid>0 );
+    sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
+        regNewRowid, regOldRowid, chngKey, onError, labelContinue, &bReplace,
+        aXRef, 0);
+
+    /* If REPLACE conflict handling may have been used, or if the PK of the
+    ** row is changing, then the GenerateConstraintChecks() above may have
+    ** moved cursor iDataCur. Reseek it. */
+    if( bReplace || chngKey ){
+      if( pPk ){
+        sqlite3VdbeAddOp4Int(v, OP_NotFound,iDataCur,labelContinue,regKey,nKey);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue,regOldRowid);
+      }
+      VdbeCoverage(v);
+    }
+
+    /* Do FK constraint checks. */
+    if( hasFK ){
+      sqlite3FkCheck(pParse, pTab, regOldRowid, 0, aXRef, chngKey);
+    }
+
+    /* Delete the index entries associated with the current record.  */
+    sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur, aRegIdx, -1);
+
+    /* We must run the OP_FinishSeek opcode to resolve a prior
+    ** OP_DeferredSeek if there is any possibility that there have been
+    ** no OP_Column opcodes since the OP_DeferredSeek was issued.  But
+    ** we want to avoid the OP_FinishSeek if possible, as running it
+    ** costs CPU cycles. */
+    if( bFinishSeek ){
+      sqlite3VdbeAddOp1(v, OP_FinishSeek, iDataCur);
+    }
+
+    /* If changing the rowid value, or if there are foreign key constraints
+    ** to process, delete the old record. Otherwise, add a noop OP_Delete
+    ** to invoke the pre-update hook.
+    **
+    ** That (regNew==regnewRowid+1) is true is also important for the
+    ** pre-update hook. If the caller invokes preupdate_new(), the returned
+    ** value is copied from memory cell (regNewRowid+1+iCol), where iCol
+    ** is the column index supplied by the user.
+    */
+    assert( regNew==regNewRowid+1 );
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    sqlite3VdbeAddOp3(v, OP_Delete, iDataCur,
+        OPFLAG_ISUPDATE | ((hasFK>1 || chngKey) ? 0 : OPFLAG_ISNOOP),
+        regNewRowid
+    );
+    if( eOnePass==ONEPASS_MULTI ){
+      assert( hasFK==0 && chngKey==0 );
+      sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION);
+    }
+    if( !pParse->nested ){
+      sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+    }
+#else
+    if( hasFK>1 || chngKey ){
+      sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, 0);
+    }
+#endif
+
+    if( hasFK ){
+      sqlite3FkCheck(pParse, pTab, 0, regNewRowid, aXRef, chngKey);
+    }
+
+    /* Insert the new index entries and the new record. */
+    sqlite3CompleteInsertion(
+        pParse, pTab, iDataCur, iIdxCur, regNewRowid, aRegIdx,
+        OPFLAG_ISUPDATE | (eOnePass==ONEPASS_MULTI ? OPFLAG_SAVEPOSITION : 0),
+        0, 0
+    );
+
+    /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
+    ** handle rows (possibly in other tables) that refer via a foreign key
+    ** to the row just updated. */
+    if( hasFK ){
+      sqlite3FkActions(pParse, pTab, pChanges, regOldRowid, aXRef, chngKey);
+    }
+  }
+
+  /* Increment the row counter
+  */
+  if( regRowCount ){
+    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
+  }
+
+  if( pTrigger ){
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
+        TRIGGER_AFTER, pTab, regOldRowid, onError, labelContinue);
+  }
+
+  /* Repeat the above with the next record to be updated, until
+  ** all record selected by the WHERE clause have been updated.
+  */
+  if( eOnePass==ONEPASS_SINGLE ){
+    /* Nothing to do at end-of-loop for a single-pass */
+  }else if( eOnePass==ONEPASS_MULTI ){
+    sqlite3VdbeResolveLabel(v, labelContinue);
+    sqlite3WhereEnd(pWInfo);
+  }else{
+    sqlite3VdbeResolveLabel(v, labelContinue);
+    sqlite3VdbeAddOp2(v, OP_Next, iEph, addrTop); VdbeCoverage(v);
+  }
+  sqlite3VdbeResolveLabel(v, labelBreak);
+
+  /* Update the sqlite_sequence table by storing the content of the
+  ** maximum rowid counter values recorded while inserting into
+  ** autoincrement tables.
+  */
+  if( pParse->nested==0 && pParse->pTriggerTab==0 && pUpsert==0 ){
+    sqlite3AutoincrementEnd(pParse);
+  }
+
+  /*
+  ** Return the number of rows that were changed, if we are tracking
+  ** that information.
+  */
+  if( regRowCount ){
+    sqlite3CodeChangeCount(v, regRowCount, "rows updated");
+  }
+
+update_cleanup:
+  sqlite3AuthContextPop(&sContext);
+  sqlite3DbFree(db, aXRef); /* Also frees aRegIdx[] and aToOpen[] */
+  sqlite3SrcListDelete(db, pTabList);
+  sqlite3ExprListDelete(db, pChanges);
+  sqlite3ExprDelete(db, pWhere);
+#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT)
+  sqlite3ExprListDelete(db, pOrderBy);
+  sqlite3ExprDelete(db, pLimit);
+#endif
+  return;
+}
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** they may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Generate code for an UPDATE of a virtual table.
+**
+** There are two possible strategies - the default and the special
+** "onepass" strategy. Onepass is only used if the virtual table
+** implementation indicates that pWhere may match at most one row.
+**
+** The default strategy is to create an ephemeral table that contains
+** for each row to be changed:
+**
+**   (A)  The original rowid of that row.
+**   (B)  The revised rowid for the row.
+**   (C)  The content of every column in the row.
+**
+** Then loop through the contents of this ephemeral table executing a
+** VUpdate for each row. When finished, drop the ephemeral table.
+**
+** The "onepass" strategy does not use an ephemeral table. Instead, it
+** stores the same values (A, B and C above) in a register array and
+** makes a single invocation of VUpdate.
+*/
+static void updateVirtualTable(
+  Parse *pParse,       /* The parsing context */
+  SrcList *pSrc,       /* The virtual table to be modified */
+  Table *pTab,         /* The virtual table */
+  ExprList *pChanges,  /* The columns to change in the UPDATE statement */
+  Expr *pRowid,        /* Expression used to recompute the rowid */
+  int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
+  Expr *pWhere,        /* WHERE clause of the UPDATE statement */
+  int onError          /* ON CONFLICT strategy */
+){
+  Vdbe *v = pParse->pVdbe;  /* Virtual machine under construction */
+  int ephemTab;             /* Table holding the result of the SELECT */
+  int i;                    /* Loop counter */
+  sqlite3 *db = pParse->db; /* Database connection */
+  const char *pVTab = (const char*)sqlite3GetVTable(db, pTab);
+  WhereInfo *pWInfo = 0;
+  int nArg = 2 + pTab->nCol;      /* Number of arguments to VUpdate */
+  int regArg;                     /* First register in VUpdate arg array */
+  int regRec;                     /* Register in which to assemble record */
+  int regRowid;                   /* Register for ephemeral table rowid */
+  int iCsr = pSrc->a[0].iCursor;  /* Cursor used for virtual table scan */
+  int aDummy[2];                  /* Unused arg for sqlite3WhereOkOnePass() */
+  int eOnePass;                   /* True to use onepass strategy */
+  int addr;                       /* Address of OP_OpenEphemeral */
+
+  /* Allocate nArg registers in which to gather the arguments for VUpdate. Then
+  ** create and open the ephemeral table in which the records created from
+  ** these arguments will be temporarily stored. */
+  assert( v );
+  ephemTab = pParse->nTab++;
+  addr= sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, nArg);
+  regArg = pParse->nMem + 1;
+  pParse->nMem += nArg;
+  if( pSrc->nSrc>1 ){
+    Index *pPk = 0;
+    Expr *pRow;
+    ExprList *pList;
+    if( HasRowid(pTab) ){
+      if( pRowid ){
+        pRow = sqlite3ExprDup(db, pRowid, 0);
+      }else{
+        pRow = sqlite3PExpr(pParse, TK_ROW, 0, 0);
+      }
+    }else{
+      i16 iPk;      /* PRIMARY KEY column */
+      pPk = sqlite3PrimaryKeyIndex(pTab);
+      assert( pPk!=0 );
+      assert( pPk->nKeyCol==1 );
+      iPk = pPk->aiColumn[0];
+      if( aXRef[iPk]>=0 ){
+        pRow = sqlite3ExprDup(db, pChanges->a[aXRef[iPk]].pExpr, 0);
+      }else{
+        pRow = exprRowColumn(pParse, iPk);
+      }
+    }
+    pList = sqlite3ExprListAppend(pParse, 0, pRow);
+
+    for(i=0; i<pTab->nCol; i++){
+      if( aXRef[i]>=0 ){
+        pList = sqlite3ExprListAppend(pParse, pList,
+          sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr, 0)
+        );
+      }else{
+        Expr *pRowExpr = exprRowColumn(pParse, i);
+        if( pRowExpr ) pRowExpr->op2 = OPFLAG_NOCHNG;
+        pList = sqlite3ExprListAppend(pParse, pList, pRowExpr);
+      }
+    }
+
+    updateFromSelect(pParse, ephemTab, pPk, pList, pSrc, pWhere, 0, 0);
+    sqlite3ExprListDelete(db, pList);
+    eOnePass = ONEPASS_OFF;
+  }else{
+    regRec = ++pParse->nMem;
+    regRowid = ++pParse->nMem;
+
+    /* Start scanning the virtual table */
+    pWInfo = sqlite3WhereBegin(
+        pParse, pSrc, pWhere, 0, 0, 0, WHERE_ONEPASS_DESIRED, 0
+    );
+    if( pWInfo==0 ) return;
+
+    /* Populate the argument registers. */
+    for(i=0; i<pTab->nCol; i++){
+      assert( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)==0 );
+      if( aXRef[i]>=0 ){
+        sqlite3ExprCode(pParse, pChanges->a[aXRef[i]].pExpr, regArg+2+i);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_VColumn, iCsr, i, regArg+2+i);
+        sqlite3VdbeChangeP5(v, OPFLAG_NOCHNG);/* For sqlite3_vtab_nochange() */
+      }
+    }
+    if( HasRowid(pTab) ){
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg);
+      if( pRowid ){
+        sqlite3ExprCode(pParse, pRowid, regArg+1);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg+1);
+      }
+    }else{
+      Index *pPk;   /* PRIMARY KEY index */
+      i16 iPk;      /* PRIMARY KEY column */
+      pPk = sqlite3PrimaryKeyIndex(pTab);
+      assert( pPk!=0 );
+      assert( pPk->nKeyCol==1 );
+      iPk = pPk->aiColumn[0];
+      sqlite3VdbeAddOp3(v, OP_VColumn, iCsr, iPk, regArg);
+      sqlite3VdbeAddOp2(v, OP_SCopy, regArg+2+iPk, regArg+1);
+    }
+
+    eOnePass = sqlite3WhereOkOnePass(pWInfo, aDummy);
+
+    /* There is no ONEPASS_MULTI on virtual tables */
+    assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE );
+
+    if( eOnePass ){
+      /* If using the onepass strategy, no-op out the OP_OpenEphemeral coded
+      ** above. */
+      sqlite3VdbeChangeToNoop(v, addr);
+      sqlite3VdbeAddOp1(v, OP_Close, iCsr);
+    }else{
+      /* Create a record from the argument register contents and insert it into
+      ** the ephemeral table. */
+      sqlite3MultiWrite(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regArg, nArg, regRec);
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_ENABLE_NULL_TRIM)
+      /* Signal an assert() within OP_MakeRecord that it is allowed to
+      ** accept no-change records with serial_type 10 */
+      sqlite3VdbeChangeP5(v, OPFLAG_NOCHNG_MAGIC);
+#endif
+      sqlite3VdbeAddOp2(v, OP_NewRowid, ephemTab, regRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, ephemTab, regRec, regRowid);
+    }
+  }
+
+
+  if( eOnePass==ONEPASS_OFF ){
+    /* End the virtual table scan */
+    if( pSrc->nSrc==1 ){
+      sqlite3WhereEnd(pWInfo);
+    }
+
+    /* Begin scanning through the ephemeral table. */
+    addr = sqlite3VdbeAddOp1(v, OP_Rewind, ephemTab); VdbeCoverage(v);
+
+    /* Extract arguments from the current row of the ephemeral table and
+    ** invoke the VUpdate method.  */
+    for(i=0; i<nArg; i++){
+      sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i, regArg+i);
+    }
+  }
+  sqlite3VtabMakeWritable(pParse, pTab);
+  sqlite3VdbeAddOp4(v, OP_VUpdate, 0, nArg, regArg, pVTab, P4_VTAB);
+  sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
+  sqlite3MayAbort(pParse);
+
+  /* End of the ephemeral table scan. Or, if using the onepass strategy,
+  ** jump to here if the scan visited zero rows. */
+  if( eOnePass==ONEPASS_OFF ){
+    sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr);
+    sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
+  }else{
+    sqlite3WhereEnd(pWInfo);
+  }
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/************** End of update.c **********************************************/
+/************** Begin file upsert.c ******************************************/
+/*
+** 2018-04-12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code to implement various aspects of UPSERT
+** processing and handling of the Upsert object.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_UPSERT
+/*
+** Free a list of Upsert objects
+*/
+static void SQLITE_NOINLINE upsertDelete(sqlite3 *db, Upsert *p){
+  do{
+    Upsert *pNext = p->pNextUpsert;
+    sqlite3ExprListDelete(db, p->pUpsertTarget);
+    sqlite3ExprDelete(db, p->pUpsertTargetWhere);
+    sqlite3ExprListDelete(db, p->pUpsertSet);
+    sqlite3ExprDelete(db, p->pUpsertWhere);
+    sqlite3DbFree(db, p->pToFree);
+    sqlite3DbFree(db, p);
+    p = pNext;
+  }while( p );
+}
+SQLITE_PRIVATE void sqlite3UpsertDelete(sqlite3 *db, Upsert *p){
+  if( p ) upsertDelete(db, p);
+}
+
+
+/*
+** Duplicate an Upsert object.
+*/
+SQLITE_PRIVATE Upsert *sqlite3UpsertDup(sqlite3 *db, Upsert *p){
+  if( p==0 ) return 0;
+  return sqlite3UpsertNew(db,
+           sqlite3ExprListDup(db, p->pUpsertTarget, 0),
+           sqlite3ExprDup(db, p->pUpsertTargetWhere, 0),
+           sqlite3ExprListDup(db, p->pUpsertSet, 0),
+           sqlite3ExprDup(db, p->pUpsertWhere, 0),
+           sqlite3UpsertDup(db, p->pNextUpsert)
+         );
+}
+
+/*
+** Create a new Upsert object.
+*/
+SQLITE_PRIVATE Upsert *sqlite3UpsertNew(
+  sqlite3 *db,           /* Determines which memory allocator to use */
+  ExprList *pTarget,     /* Target argument to ON CONFLICT, or NULL */
+  Expr *pTargetWhere,    /* Optional WHERE clause on the target */
+  ExprList *pSet,        /* UPDATE columns, or NULL for a DO NOTHING */
+  Expr *pWhere,          /* WHERE clause for the ON CONFLICT UPDATE */
+  Upsert *pNext          /* Next ON CONFLICT clause in the list */
+){
+  Upsert *pNew;
+  pNew = sqlite3DbMallocZero(db, sizeof(Upsert));
+  if( pNew==0 ){
+    sqlite3ExprListDelete(db, pTarget);
+    sqlite3ExprDelete(db, pTargetWhere);
+    sqlite3ExprListDelete(db, pSet);
+    sqlite3ExprDelete(db, pWhere);
+    sqlite3UpsertDelete(db, pNext);
+    return 0;
+  }else{
+    pNew->pUpsertTarget = pTarget;
+    pNew->pUpsertTargetWhere = pTargetWhere;
+    pNew->pUpsertSet = pSet;
+    pNew->pUpsertWhere = pWhere;
+    pNew->isDoUpdate = pSet!=0;
+    pNew->pNextUpsert = pNext;
+  }
+  return pNew;
+}
+
+/*
+** Analyze the ON CONFLICT clause described by pUpsert.  Resolve all
+** symbols in the conflict-target.
+**
+** Return SQLITE_OK if everything works, or an error code is something
+** is wrong.
+*/
+SQLITE_PRIVATE int sqlite3UpsertAnalyzeTarget(
+  Parse *pParse,     /* The parsing context */
+  SrcList *pTabList, /* Table into which we are inserting */
+  Upsert *pUpsert,   /* The ON CONFLICT clauses */
+  Upsert *pAll       /* Complete list of all ON CONFLICT clauses */
+){
+  Table *pTab;            /* That table into which we are inserting */
+  int rc;                 /* Result code */
+  int iCursor;            /* Cursor used by pTab */
+  Index *pIdx;            /* One of the indexes of pTab */
+  ExprList *pTarget;      /* The conflict-target clause */
+  Expr *pTerm;            /* One term of the conflict-target clause */
+  NameContext sNC;        /* Context for resolving symbolic names */
+  Expr sCol[2];           /* Index column converted into an Expr */
+  int nClause = 0;        /* Counter of ON CONFLICT clauses */
+
+  assert( pTabList->nSrc==1 );
+  assert( pTabList->a[0].pSTab!=0 );
+  assert( pUpsert!=0 );
+  assert( pUpsert->pUpsertTarget!=0 );
+
+  /* Resolve all symbolic names in the conflict-target clause, which
+  ** includes both the list of columns and the optional partial-index
+  ** WHERE clause.
+  */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  sNC.pSrcList = pTabList;
+  for(; pUpsert && pUpsert->pUpsertTarget;
+        pUpsert=pUpsert->pNextUpsert, nClause++){
+    rc = sqlite3ResolveExprListNames(&sNC, pUpsert->pUpsertTarget);
+    if( rc ) return rc;
+    rc = sqlite3ResolveExprNames(&sNC, pUpsert->pUpsertTargetWhere);
+    if( rc ) return rc;
+
+    /* Check to see if the conflict target matches the rowid. */
+    pTab = pTabList->a[0].pSTab;
+    pTarget = pUpsert->pUpsertTarget;
+    iCursor = pTabList->a[0].iCursor;
+    if( HasRowid(pTab)
+     && pTarget->nExpr==1
+     && (pTerm = pTarget->a[0].pExpr)->op==TK_COLUMN
+     && pTerm->iColumn==XN_ROWID
+    ){
+      /* The conflict-target is the rowid of the primary table */
+      assert( pUpsert->pUpsertIdx==0 );
+      continue;
+    }
+
+    /* Initialize sCol[0..1] to be an expression parse tree for a
+    ** single column of an index.  The sCol[0] node will be the TK_COLLATE
+    ** operator and sCol[1] will be the TK_COLUMN operator.  Code below
+    ** will populate the specific collation and column number values
+    ** prior to comparing against the conflict-target expression.
+    */
+    memset(sCol, 0, sizeof(sCol));
+    sCol[0].op = TK_COLLATE;
+    sCol[0].pLeft = &sCol[1];
+    sCol[1].op = TK_COLUMN;
+    sCol[1].iTable = pTabList->a[0].iCursor;
+
+    /* Check for matches against other indexes */
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      int ii, jj, nn;
+      if( !IsUniqueIndex(pIdx) ) continue;
+      if( pTarget->nExpr!=pIdx->nKeyCol ) continue;
+      if( pIdx->pPartIdxWhere ){
+        if( pUpsert->pUpsertTargetWhere==0 ) continue;
+        if( sqlite3ExprCompare(pParse, pUpsert->pUpsertTargetWhere,
+                               pIdx->pPartIdxWhere, iCursor)!=0 ){
+          continue;
+        }
+      }
+      nn = pIdx->nKeyCol;
+      for(ii=0; ii<nn; ii++){
+        Expr *pExpr;
+        sCol[0].u.zToken = (char*)pIdx->azColl[ii];
+        if( pIdx->aiColumn[ii]==XN_EXPR ){
+          assert( pIdx->aColExpr!=0 );
+          assert( pIdx->aColExpr->nExpr>ii );
+          assert( pIdx->bHasExpr );
+          pExpr = pIdx->aColExpr->a[ii].pExpr;
+          if( pExpr->op!=TK_COLLATE ){
+            sCol[0].pLeft = pExpr;
+            pExpr = &sCol[0];
+          }
+        }else{
+          sCol[0].pLeft = &sCol[1];
+          sCol[1].iColumn = pIdx->aiColumn[ii];
+          pExpr = &sCol[0];
+        }
+        for(jj=0; jj<nn; jj++){
+          if( sqlite3ExprCompare(0,pTarget->a[jj].pExpr,pExpr,iCursor)<2 ){
+            break;  /* Column ii of the index matches column jj of target */
+          }
+        }
+        if( jj>=nn ){
+          /* The target contains no match for column jj of the index */
+          break;
+        }
+      }
+      if( ii<nn ){
+        /* Column ii of the index did not match any term of the conflict target.
+        ** Continue the search with the next index. */
+        continue;
+      }
+      pUpsert->pUpsertIdx = pIdx;
+      if( sqlite3UpsertOfIndex(pAll,pIdx)!=pUpsert ){
+        /* Really this should be an error.  The isDup ON CONFLICT clause will
+        ** never fire.  But this problem was not discovered until three years
+        ** after multi-CONFLICT upsert was added, and so we silently ignore
+        ** the problem to prevent breaking applications that might actually
+        ** have redundant ON CONFLICT clauses. */
+        pUpsert->isDup = 1;
+      }
+      break;
+    }
+    if( pUpsert->pUpsertIdx==0 ){
+      char zWhich[16];
+      if( nClause==0 && pUpsert->pNextUpsert==0 ){
+        zWhich[0] = 0;
+      }else{
+        sqlite3_snprintf(sizeof(zWhich),zWhich,"%r ", nClause+1);
+      }
+      sqlite3ErrorMsg(pParse, "%sON CONFLICT clause does not match any "
+                              "PRIMARY KEY or UNIQUE constraint", zWhich);
+      return SQLITE_ERROR;
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return true if pUpsert is the last ON CONFLICT clause with a
+** conflict target, or if pUpsert is followed by another ON CONFLICT
+** clause that targets the INTEGER PRIMARY KEY.
+*/
+SQLITE_PRIVATE int sqlite3UpsertNextIsIPK(Upsert *pUpsert){
+  Upsert *pNext;
+  if( NEVER(pUpsert==0) ) return 0;
+  pNext = pUpsert->pNextUpsert;
+  while( 1 /*exit-by-return*/ ){
+    if( pNext==0 ) return 1;
+    if( pNext->pUpsertTarget==0 ) return 1;
+    if( pNext->pUpsertIdx==0 ) return 1;
+    if( !pNext->isDup ) return 0;
+    pNext = pNext->pNextUpsert;
+  }
+  return 0;
+}
+
+/*
+** Given the list of ON CONFLICT clauses described by pUpsert, and
+** a particular index pIdx, return a pointer to the particular ON CONFLICT
+** clause that applies to the index.  Or, if the index is not subject to
+** any ON CONFLICT clause, return NULL.
+*/
+SQLITE_PRIVATE Upsert *sqlite3UpsertOfIndex(Upsert *pUpsert, Index *pIdx){
+  while(
+      pUpsert
+   && pUpsert->pUpsertTarget!=0
+   && pUpsert->pUpsertIdx!=pIdx
+  ){
+     pUpsert = pUpsert->pNextUpsert;
+  }
+  return pUpsert;
+}
+
+/*
+** Generate bytecode that does an UPDATE as part of an upsert.
+**
+** If pIdx is NULL, then the UNIQUE constraint that failed was the IPK.
+** In this case parameter iCur is a cursor open on the table b-tree that
+** currently points to the conflicting table row. Otherwise, if pIdx
+** is not NULL, then pIdx is the constraint that failed and iCur is a
+** cursor points to the conflicting row.
+*/
+SQLITE_PRIVATE void sqlite3UpsertDoUpdate(
+  Parse *pParse,        /* The parsing and code-generating context */
+  Upsert *pUpsert,      /* The ON CONFLICT clause for the upsert */
+  Table *pTab,          /* The table being updated */
+  Index *pIdx,          /* The UNIQUE constraint that failed */
+  int iCur              /* Cursor for pIdx (or pTab if pIdx==NULL) */
+){
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
+  SrcList *pSrc;            /* FROM clause for the UPDATE */
+  int iDataCur;
+  int i;
+  Upsert *pTop = pUpsert;
+
+  assert( v!=0 );
+  assert( pUpsert!=0 );
+  iDataCur = pUpsert->iDataCur;
+  pUpsert = sqlite3UpsertOfIndex(pTop, pIdx);
+  VdbeNoopComment((v, "Begin DO UPDATE of UPSERT"));
+  if( pIdx && iCur!=iDataCur ){
+    if( HasRowid(pTab) ){
+      int regRowid = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp2(v, OP_IdxRowid, iCur, regRowid);
+      sqlite3VdbeAddOp3(v, OP_SeekRowid, iDataCur, 0, regRowid);
+      VdbeCoverage(v);
+      sqlite3ReleaseTempReg(pParse, regRowid);
+    }else{
+      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+      int nPk = pPk->nKeyCol;
+      int iPk = pParse->nMem+1;
+      pParse->nMem += nPk;
+      for(i=0; i<nPk; i++){
+        int k;
+        assert( pPk->aiColumn[i]>=0 );
+        k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[i]);
+        sqlite3VdbeAddOp3(v, OP_Column, iCur, k, iPk+i);
+        VdbeComment((v, "%s.%s", pIdx->zName,
+                    pTab->aCol[pPk->aiColumn[i]].zCnName));
+      }
+      sqlite3VdbeVerifyAbortable(v, OE_Abort);
+      i = sqlite3VdbeAddOp4Int(v, OP_Found, iDataCur, 0, iPk, nPk);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CORRUPT, OE_Abort, 0,
+            "corrupt database", P4_STATIC);
+      sqlite3MayAbort(pParse);
+      sqlite3VdbeJumpHere(v, i);
+    }
+  }
+  /* pUpsert does not own pTop->pUpsertSrc - the outer INSERT statement does.
+  ** So we have to make a copy before passing it down into sqlite3Update() */
+  pSrc = sqlite3SrcListDup(db, pTop->pUpsertSrc, 0);
+  /* excluded.* columns of type REAL need to be converted to a hard real */
+  for(i=0; i<pTab->nCol; i++){
+    if( pTab->aCol[i].affinity==SQLITE_AFF_REAL ){
+      sqlite3VdbeAddOp1(v, OP_RealAffinity, pTop->regData+i);
+    }
+  }
+  sqlite3Update(pParse, pSrc, sqlite3ExprListDup(db,pUpsert->pUpsertSet,0),
+      sqlite3ExprDup(db,pUpsert->pUpsertWhere,0), OE_Abort, 0, 0, pUpsert);
+  VdbeNoopComment((v, "End DO UPDATE of UPSERT"));
+}
+
+#endif /* SQLITE_OMIT_UPSERT */
+
+/************** End of upsert.c **********************************************/
+/************** Begin file vacuum.c ******************************************/
+/*
+** 2003 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the VACUUM command.
+**
+** Most of the code in this file may be omitted by defining the
+** SQLITE_OMIT_VACUUM macro.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
+
+/*
+** Execute zSql on database db.
+**
+** If zSql returns rows, then each row will have exactly one
+** column.  (This will only happen if zSql begins with "SELECT".)
+** Take each row of result and call execSql() again recursively.
+**
+** The execSqlF() routine does the same thing, except it accepts
+** a format string as its third argument
+*/
+static int execSql(sqlite3 *db, char **pzErrMsg, const char *zSql){
+  sqlite3_stmt *pStmt;
+  int rc;
+
+  /* printf("SQL: [%s]\n", zSql); fflush(stdout); */
+  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  while( SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
+    const char *zSubSql = (const char*)sqlite3_column_text(pStmt,0);
+    assert( sqlite3_strnicmp(zSql,"SELECT",6)==0 );
+    /* The secondary SQL must be one of CREATE TABLE, CREATE INDEX,
+    ** or INSERT.  Historically there have been attacks that first
+    ** corrupt the sqlite_schema.sql field with other kinds of statements
+    ** then run VACUUM to get those statements to execute at inappropriate
+    ** times. */
+    if( zSubSql
+     && (strncmp(zSubSql,"CRE",3)==0 || strncmp(zSubSql,"INS",3)==0)
+    ){
+      rc = execSql(db, pzErrMsg, zSubSql);
+      if( rc!=SQLITE_OK ) break;
+    }
+  }
+  assert( rc!=SQLITE_ROW );
+  if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  if( rc ){
+    sqlite3SetString(pzErrMsg, db, sqlite3_errmsg(db));
+  }
+  (void)sqlite3_finalize(pStmt);
+  return rc;
+}
+static int execSqlF(sqlite3 *db, char **pzErrMsg, const char *zSql, ...){
+  char *z;
+  va_list ap;
+  int rc;
+  va_start(ap, zSql);
+  z = sqlite3VMPrintf(db, zSql, ap);
+  va_end(ap);
+  if( z==0 ) return SQLITE_NOMEM;
+  rc = execSql(db, pzErrMsg, z);
+  sqlite3DbFree(db, z);
+  return rc;
+}
+
+/*
+** The VACUUM command is used to clean up the database,
+** collapse free space, etc.  It is modelled after the VACUUM command
+** in PostgreSQL.  The VACUUM command works as follows:
+**
+**   (1)  Create a new transient database file
+**   (2)  Copy all content from the database being vacuumed into
+**        the new transient database file
+**   (3)  Copy content from the transient database back into the
+**        original database.
+**
+** The transient database requires temporary disk space approximately
+** equal to the size of the original database.  The copy operation of
+** step (3) requires additional temporary disk space approximately equal
+** to the size of the original database for the rollback journal.
+** Hence, temporary disk space that is approximately 2x the size of the
+** original database is required.  Every page of the database is written
+** approximately 3 times:  Once for step (2) and twice for step (3).
+** Two writes per page are required in step (3) because the original
+** database content must be written into the rollback journal prior to
+** overwriting the database with the vacuumed content.
+**
+** Only 1x temporary space and only 1x writes would be required if
+** the copy of step (3) were replaced by deleting the original database
+** and renaming the transient database as the original.  But that will
+** not work if other processes are attached to the original database.
+** And a power loss in between deleting the original and renaming the
+** transient would cause the database file to appear to be deleted
+** following reboot.
+*/
+SQLITE_PRIVATE void sqlite3Vacuum(Parse *pParse, Token *pNm, Expr *pInto){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int iDb = 0;
+  if( v==0 ) goto build_vacuum_end;
+  if( pParse->nErr ) goto build_vacuum_end;
+  if( pNm ){
+#ifndef SQLITE_BUG_COMPATIBLE_20160819
+    /* Default behavior:  Report an error if the argument to VACUUM is
+    ** not recognized */
+    iDb = sqlite3TwoPartName(pParse, pNm, pNm, &pNm);
+    if( iDb<0 ) goto build_vacuum_end;
+#else
+    /* When SQLITE_BUG_COMPATIBLE_20160819 is defined, unrecognized arguments
+    ** to VACUUM are silently ignored.  This is a back-out of a bug fix that
+    ** occurred on 2016-08-19 (https://www.sqlite.org/src/info/083f9e6270).
+    ** The buggy behavior is required for binary compatibility with some
+    ** legacy applications. */
+    iDb = sqlite3FindDb(pParse->db, pNm);
+    if( iDb<0 ) iDb = 0;
+#endif
+  }
+  if( iDb!=1 ){
+    int iIntoReg = 0;
+    if( pInto && sqlite3ResolveSelfReference(pParse,0,0,pInto,0)==0 ){
+      iIntoReg = ++pParse->nMem;
+      sqlite3ExprCode(pParse, pInto, iIntoReg);
+    }
+    sqlite3VdbeAddOp2(v, OP_Vacuum, iDb, iIntoReg);
+    sqlite3VdbeUsesBtree(v, iDb);
+  }
+build_vacuum_end:
+  sqlite3ExprDelete(pParse->db, pInto);
+  return;
+}
+
+/*
+** This routine implements the OP_Vacuum opcode of the VDBE.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3RunVacuum(
+  char **pzErrMsg,        /* Write error message here */
+  sqlite3 *db,            /* Database connection */
+  int iDb,                /* Which attached DB to vacuum */
+  sqlite3_value *pOut     /* Write results here, if not NULL. VACUUM INTO */
+){
+  int rc = SQLITE_OK;     /* Return code from service routines */
+  Btree *pMain;           /* The database being vacuumed */
+  Btree *pTemp;           /* The temporary database we vacuum into */
+  u32 saved_mDbFlags;     /* Saved value of db->mDbFlags */
+  u64 saved_flags;        /* Saved value of db->flags */
+  i64 saved_nChange;      /* Saved value of db->nChange */
+  i64 saved_nTotalChange; /* Saved value of db->nTotalChange */
+  u32 saved_openFlags;    /* Saved value of db->openFlags */
+  u8 saved_mTrace;        /* Saved trace settings */
+  Db *pDb = 0;            /* Database to detach at end of vacuum */
+  int isMemDb;            /* True if vacuuming a :memory: database */
+  int nRes;               /* Bytes of reserved space at the end of each page */
+  int nDb;                /* Number of attached databases */
+  const char *zDbMain;    /* Schema name of database to vacuum */
+  const char *zOut;       /* Name of output file */
+  u32 pgflags = PAGER_SYNCHRONOUS_OFF; /* sync flags for output db */
+  u64 iRandom;            /* Random value used for zDbVacuum[] */
+  char zDbVacuum[42];     /* Name of the ATTACH-ed database used for vacuum */
+
+
+  if( !db->autoCommit ){
+    sqlite3SetString(pzErrMsg, db, "cannot VACUUM from within a transaction");
+    return SQLITE_ERROR; /* IMP: R-12218-18073 */
+  }
+  if( db->nVdbeActive>1 ){
+    sqlite3SetString(pzErrMsg, db,"cannot VACUUM - SQL statements in progress");
+    return SQLITE_ERROR; /* IMP: R-15610-35227 */
+  }
+  saved_openFlags = db->openFlags;
+  if( pOut ){
+    if( sqlite3_value_type(pOut)!=SQLITE_TEXT ){
+      sqlite3SetString(pzErrMsg, db, "non-text filename");
+      return SQLITE_ERROR;
+    }
+    zOut = (const char*)sqlite3_value_text(pOut);
+    db->openFlags &= ~SQLITE_OPEN_READONLY;
+    db->openFlags |= SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE;
+  }else{
+    zOut = "";
+  }
+
+  /* Save the current value of the database flags so that it can be
+  ** restored before returning. Then set the writable-schema flag, and
+  ** disable CHECK and foreign key constraints.  */
+  saved_flags = db->flags;
+  saved_mDbFlags = db->mDbFlags;
+  saved_nChange = db->nChange;
+  saved_nTotalChange = db->nTotalChange;
+  saved_mTrace = db->mTrace;
+  db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks;
+  db->mDbFlags |= DBFLAG_PreferBuiltin | DBFLAG_Vacuum;
+  db->flags &= ~(u64)(SQLITE_ForeignKeys | SQLITE_ReverseOrder
+                   | SQLITE_Defensive | SQLITE_CountRows);
+  db->mTrace = 0;
+
+  zDbMain = db->aDb[iDb].zDbSName;
+  pMain = db->aDb[iDb].pBt;
+  isMemDb = sqlite3PagerIsMemdb(sqlite3BtreePager(pMain));
+
+  /* Attach the temporary database as 'vacuum_XXXXXX'. The synchronous pragma
+  ** can be set to 'off' for this file, as it is not recovered if a crash
+  ** occurs anyway. The integrity of the database is maintained by a
+  ** (possibly synchronous) transaction opened on the main database before
+  ** sqlite3BtreeCopyFile() is called.
+  **
+  ** An optimization would be to use a non-journaled pager.
+  ** (Later:) I tried setting "PRAGMA vacuum_XXXXXX.journal_mode=OFF" but
+  ** that actually made the VACUUM run slower.  Very little journalling
+  ** actually occurs when doing a vacuum since the vacuum_db is initially
+  ** empty.  Only the journal header is written.  Apparently it takes more
+  ** time to parse and run the PRAGMA to turn journalling off than it does
+  ** to write the journal header file.
+  */
+  sqlite3_randomness(sizeof(iRandom),&iRandom);
+  sqlite3_snprintf(sizeof(zDbVacuum), zDbVacuum, "vacuum_%016llx", iRandom);
+  nDb = db->nDb;
+  rc = execSqlF(db, pzErrMsg, "ATTACH %Q AS %s", zOut, zDbVacuum);
+  db->openFlags = saved_openFlags;
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  assert( (db->nDb-1)==nDb );
+  pDb = &db->aDb[nDb];
+  assert( strcmp(pDb->zDbSName,zDbVacuum)==0 );
+  pTemp = pDb->pBt;
+  if( pOut ){
+    sqlite3_file *id = sqlite3PagerFile(sqlite3BtreePager(pTemp));
+    i64 sz = 0;
+    if( id->pMethods!=0 && (sqlite3OsFileSize(id, &sz)!=SQLITE_OK || sz>0) ){
+      rc = SQLITE_ERROR;
+      sqlite3SetString(pzErrMsg, db, "output file already exists");
+      goto end_of_vacuum;
+    }
+    db->mDbFlags |= DBFLAG_VacuumInto;
+
+    /* For a VACUUM INTO, the pager-flags are set to the same values as
+    ** they are for the database being vacuumed, except that PAGER_CACHESPILL
+    ** is always set. */
+    pgflags = db->aDb[iDb].safety_level | (db->flags & PAGER_FLAGS_MASK);
+  }
+  nRes = sqlite3BtreeGetRequestedReserve(pMain);
+
+  sqlite3BtreeSetCacheSize(pTemp, db->aDb[iDb].pSchema->cache_size);
+  sqlite3BtreeSetSpillSize(pTemp, sqlite3BtreeSetSpillSize(pMain,0));
+  sqlite3BtreeSetPagerFlags(pTemp, pgflags|PAGER_CACHESPILL);
+
+  /* Begin a transaction and take an exclusive lock on the main database
+  ** file. This is done before the sqlite3BtreeGetPageSize(pMain) call below,
+  ** to ensure that we do not try to change the page-size on a WAL database.
+  */
+  rc = execSql(db, pzErrMsg, "BEGIN");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = sqlite3BtreeBeginTrans(pMain, pOut==0 ? 2 : 0, 0);
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Do not attempt to change the page size for a WAL database */
+  if( sqlite3PagerGetJournalMode(sqlite3BtreePager(pMain))
+                                               ==PAGER_JOURNALMODE_WAL
+   && pOut==0
+  ){
+    db->nextPagesize = 0;
+  }
+
+  if( sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes, 0)
+   || (!isMemDb && sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes, 0))
+   || NEVER(db->mallocFailed)
+  ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto end_of_vacuum;
+  }
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac>=0 ? db->nextAutovac :
+                                           sqlite3BtreeGetAutoVacuum(pMain));
+#endif
+
+  /* Query the schema of the main database. Create a mirror schema
+  ** in the temporary database.
+  */
+  db->init.iDb = nDb; /* force new CREATE statements into vacuum_db */
+  rc = execSqlF(db, pzErrMsg,
+      "SELECT sql FROM \"%w\".sqlite_schema"
+      " WHERE type='table'AND name<>'sqlite_sequence'"
+      " AND coalesce(rootpage,1)>0",
+      zDbMain
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = execSqlF(db, pzErrMsg,
+      "SELECT sql FROM \"%w\".sqlite_schema"
+      " WHERE type='index'",
+      zDbMain
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  db->init.iDb = 0;
+
+  /* Loop through the tables in the main database. For each, do
+  ** an "INSERT INTO vacuum_db.xxx SELECT * FROM main.xxx;" to copy
+  ** the contents to the temporary database.
+  */
+  rc = execSqlF(db, pzErrMsg,
+      "SELECT'INSERT INTO %s.'||quote(name)"
+      "||' SELECT*FROM\"%w\".'||quote(name)"
+      "FROM %s.sqlite_schema "
+      "WHERE type='table'AND coalesce(rootpage,1)>0",
+      zDbVacuum, zDbMain, zDbVacuum
+  );
+  assert( (db->mDbFlags & DBFLAG_Vacuum)!=0 );
+  db->mDbFlags &= ~DBFLAG_Vacuum;
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Copy the triggers, views, and virtual tables from the main database
+  ** over to the temporary database.  None of these objects has any
+  ** associated storage, so all we have to do is copy their entries
+  ** from the schema table.
+  */
+  rc = execSqlF(db, pzErrMsg,
+      "INSERT INTO %s.sqlite_schema"
+      " SELECT*FROM \"%w\".sqlite_schema"
+      " WHERE type IN('view','trigger')"
+      " OR(type='table'AND rootpage=0)",
+      zDbVacuum, zDbMain
+  );
+  if( rc ) goto end_of_vacuum;
+
+  /* At this point, there is a write transaction open on both the
+  ** vacuum database and the main database. Assuming no error occurs,
+  ** both transactions are closed by this block - the main database
+  ** transaction by sqlite3BtreeCopyFile() and the other by an explicit
+  ** call to sqlite3BtreeCommit().
+  */
+  {
+    u32 meta;
+    int i;
+
+    /* This array determines which meta meta values are preserved in the
+    ** vacuum.  Even entries are the meta value number and odd entries
+    ** are an increment to apply to the meta value after the vacuum.
+    ** The increment is used to increase the schema cookie so that other
+    ** connections to the same database will know to reread the schema.
+    */
+    static const unsigned char aCopy[] = {
+       BTREE_SCHEMA_VERSION,     1,  /* Add one to the old schema cookie */
+       BTREE_DEFAULT_CACHE_SIZE, 0,  /* Preserve the default page cache size */
+       BTREE_TEXT_ENCODING,      0,  /* Preserve the text encoding */
+       BTREE_USER_VERSION,       0,  /* Preserve the user version */
+       BTREE_APPLICATION_ID,     0,  /* Preserve the application id */
+    };
+
+    assert( SQLITE_TXN_WRITE==sqlite3BtreeTxnState(pTemp) );
+    assert( pOut!=0 || SQLITE_TXN_WRITE==sqlite3BtreeTxnState(pMain) );
+
+    /* Copy Btree meta values */
+    for(i=0; i<ArraySize(aCopy); i+=2){
+      /* GetMeta() and UpdateMeta() cannot fail in this context because
+      ** we already have page 1 loaded into cache and marked dirty. */
+      sqlite3BtreeGetMeta(pMain, aCopy[i], &meta);
+      rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta+aCopy[i+1]);
+      if( NEVER(rc!=SQLITE_OK) ) goto end_of_vacuum;
+    }
+
+    if( pOut==0 ){
+      rc = sqlite3BtreeCopyFile(pMain, pTemp);
+    }
+    if( rc!=SQLITE_OK ) goto end_of_vacuum;
+    rc = sqlite3BtreeCommit(pTemp);
+    if( rc!=SQLITE_OK ) goto end_of_vacuum;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pOut==0 ){
+      sqlite3BtreeSetAutoVacuum(pMain, sqlite3BtreeGetAutoVacuum(pTemp));
+    }
+#endif
+  }
+
+  assert( rc==SQLITE_OK );
+  if( pOut==0 ){
+    nRes = sqlite3BtreeGetRequestedReserve(pTemp);
+    rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes,1);
+  }
+
+end_of_vacuum:
+  /* Restore the original value of db->flags */
+  db->init.iDb = 0;
+  db->mDbFlags = saved_mDbFlags;
+  db->flags = saved_flags;
+  db->nChange = saved_nChange;
+  db->nTotalChange = saved_nTotalChange;
+  db->mTrace = saved_mTrace;
+  sqlite3BtreeSetPageSize(pMain, -1, 0, 1);
+
+  /* Currently there is an SQL level transaction open on the vacuum
+  ** database. No locks are held on any other files (since the main file
+  ** was committed at the btree level). So it safe to end the transaction
+  ** by manually setting the autoCommit flag to true and detaching the
+  ** vacuum database. The vacuum_db journal file is deleted when the pager
+  ** is closed by the DETACH.
+  */
+  db->autoCommit = 1;
+
+  if( pDb ){
+    sqlite3BtreeClose(pDb->pBt);
+    pDb->pBt = 0;
+    pDb->pSchema = 0;
+  }
+
+  /* This both clears the schemas and reduces the size of the db->aDb[]
+  ** array. */
+  sqlite3ResetAllSchemasOfConnection(db);
+
+  return rc;
+}
+
+#endif  /* SQLITE_OMIT_VACUUM && SQLITE_OMIT_ATTACH */
+
+/************** End of vacuum.c **********************************************/
+/************** Begin file vtab.c ********************************************/
+/*
+** 2006 June 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to help implement virtual tables.
+*/
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* #include "sqliteInt.h" */
+
+/*
+** Before a virtual table xCreate() or xConnect() method is invoked, the
+** sqlite3.pVtabCtx member variable is set to point to an instance of
+** this struct allocated on the stack. It is used by the implementation of
+** the sqlite3_declare_vtab() and sqlite3_vtab_config() APIs, both of which
+** are invoked only from within xCreate and xConnect methods.
+*/
+struct VtabCtx {
+  VTable *pVTable;    /* The virtual table being constructed */
+  Table *pTab;        /* The Table object to which the virtual table belongs */
+  VtabCtx *pPrior;    /* Parent context (if any) */
+  int bDeclared;      /* True after sqlite3_declare_vtab() is called */
+};
+
+/*
+** Construct and install a Module object for a virtual table.  When this
+** routine is called, it is guaranteed that all appropriate locks are held
+** and the module is not already part of the connection.
+**
+** If there already exists a module with zName, replace it with the new one.
+** If pModule==0, then delete the module zName if it exists.
+*/
+SQLITE_PRIVATE Module *sqlite3VtabCreateModule(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux,                     /* Context pointer for xCreate/xConnect */
+  void (*xDestroy)(void *)        /* Module destructor function */
+){
+  Module *pMod;
+  Module *pDel;
+  char *zCopy;
+  if( pModule==0 ){
+    zCopy = (char*)zName;
+    pMod = 0;
+  }else{
+    int nName = sqlite3Strlen30(zName);
+    pMod = (Module *)sqlite3Malloc(sizeof(Module) + nName + 1);
+    if( pMod==0 ){
+      sqlite3OomFault(db);
+      return 0;
+    }
+    zCopy = (char *)(&pMod[1]);
+    memcpy(zCopy, zName, nName+1);
+    pMod->zName = zCopy;
+    pMod->pModule = pModule;
+    pMod->pAux = pAux;
+    pMod->xDestroy = xDestroy;
+    pMod->pEpoTab = 0;
+    pMod->nRefModule = 1;
+  }
+  pDel = (Module *)sqlite3HashInsert(&db->aModule,zCopy,(void*)pMod);
+  if( pDel ){
+    if( pDel==pMod ){
+      sqlite3OomFault(db);
+      sqlite3DbFree(db, pDel);
+      pMod = 0;
+    }else{
+      sqlite3VtabEponymousTableClear(db, pDel);
+      sqlite3VtabModuleUnref(db, pDel);
+    }
+  }
+  return pMod;
+}
+
+/*
+** The actual function that does the work of creating a new module.
+** This function implements the sqlite3_create_module() and
+** sqlite3_create_module_v2() interfaces.
+*/
+static int createModule(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux,                     /* Context pointer for xCreate/xConnect */
+  void (*xDestroy)(void *)        /* Module destructor function */
+){
+  int rc = SQLITE_OK;
+
+  sqlite3_mutex_enter(db->mutex);
+  (void)sqlite3VtabCreateModule(db, zName, pModule, pAux, xDestroy);
+  rc = sqlite3ApiExit(db, rc);
+  if( rc!=SQLITE_OK && xDestroy ) xDestroy(pAux);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+
+/*
+** External API function used to create a new virtual-table module.
+*/
+SQLITE_API int sqlite3_create_module(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux                      /* Context pointer for xCreate/xConnect */
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  return createModule(db, zName, pModule, pAux, 0);
+}
+
+/*
+** External API function used to create a new virtual-table module.
+*/
+SQLITE_API int sqlite3_create_module_v2(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux,                     /* Context pointer for xCreate/xConnect */
+  void (*xDestroy)(void *)        /* Module destructor function */
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  return createModule(db, zName, pModule, pAux, xDestroy);
+}
+
+/*
+** External API to drop all virtual-table modules, except those named
+** on the azNames list.
+*/
+SQLITE_API int sqlite3_drop_modules(sqlite3 *db, const char** azNames){
+  HashElem *pThis, *pNext;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  for(pThis=sqliteHashFirst(&db->aModule); pThis; pThis=pNext){
+    Module *pMod = (Module*)sqliteHashData(pThis);
+    pNext = sqliteHashNext(pThis);
+    if( azNames ){
+      int ii;
+      for(ii=0; azNames[ii]!=0 && strcmp(azNames[ii],pMod->zName)!=0; ii++){}
+      if( azNames[ii]!=0 ) continue;
+    }
+    createModule(db, pMod->zName, 0, 0, 0);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Decrement the reference count on a Module object.  Destroy the
+** module when the reference count reaches zero.
+*/
+SQLITE_PRIVATE void sqlite3VtabModuleUnref(sqlite3 *db, Module *pMod){
+  assert( pMod->nRefModule>0 );
+  pMod->nRefModule--;
+  if( pMod->nRefModule==0 ){
+    if( pMod->xDestroy ){
+      pMod->xDestroy(pMod->pAux);
+    }
+    assert( pMod->pEpoTab==0 );
+    sqlite3DbFree(db, pMod);
+  }
+}
+
+/*
+** Lock the virtual table so that it cannot be disconnected.
+** Locks nest.  Every lock should have a corresponding unlock.
+** If an unlock is omitted, resources leaks will occur.
+**
+** If a disconnect is attempted while a virtual table is locked,
+** the disconnect is deferred until all locks have been removed.
+*/
+SQLITE_PRIVATE void sqlite3VtabLock(VTable *pVTab){
+  pVTab->nRef++;
+}
+
+
+/*
+** pTab is a pointer to a Table structure representing a virtual-table.
+** Return a pointer to the VTable object used by connection db to access
+** this virtual-table, if one has been created, or NULL otherwise.
+*/
+SQLITE_PRIVATE VTable *sqlite3GetVTable(sqlite3 *db, Table *pTab){
+  VTable *pVtab;
+  assert( IsVirtual(pTab) );
+  for(pVtab=pTab->u.vtab.p; pVtab && pVtab->db!=db; pVtab=pVtab->pNext);
+  return pVtab;
+}
+
+/*
+** Decrement the ref-count on a virtual table object. When the ref-count
+** reaches zero, call the xDisconnect() method to delete the object.
+*/
+SQLITE_PRIVATE void sqlite3VtabUnlock(VTable *pVTab){
+  sqlite3 *db = pVTab->db;
+
+  assert( db );
+  assert( pVTab->nRef>0 );
+  assert( db->eOpenState==SQLITE_STATE_OPEN
+       || db->eOpenState==SQLITE_STATE_ZOMBIE );
+
+  pVTab->nRef--;
+  if( pVTab->nRef==0 ){
+    sqlite3_vtab *p = pVTab->pVtab;
+    if( p ){
+      p->pModule->xDisconnect(p);
+    }
+    sqlite3VtabModuleUnref(pVTab->db, pVTab->pMod);
+    sqlite3DbFree(db, pVTab);
+  }
+}
+
+/*
+** Table p is a virtual table. This function moves all elements in the
+** p->u.vtab.p list to the sqlite3.pDisconnect lists of their associated
+** database connections to be disconnected at the next opportunity.
+** Except, if argument db is not NULL, then the entry associated with
+** connection db is left in the p->u.vtab.p list.
+*/
+static VTable *vtabDisconnectAll(sqlite3 *db, Table *p){
+  VTable *pRet = 0;
+  VTable *pVTable;
+
+  assert( IsVirtual(p) );
+  pVTable = p->u.vtab.p;
+  p->u.vtab.p = 0;
+
+  /* Assert that the mutex (if any) associated with the BtShared database
+  ** that contains table p is held by the caller. See header comments
+  ** above function sqlite3VtabUnlockList() for an explanation of why
+  ** this makes it safe to access the sqlite3.pDisconnect list of any
+  ** database connection that may have an entry in the p->u.vtab.p list.
+  */
+  assert( db==0 || sqlite3SchemaMutexHeld(db, 0, p->pSchema) );
+
+  while( pVTable ){
+    sqlite3 *db2 = pVTable->db;
+    VTable *pNext = pVTable->pNext;
+    assert( db2 );
+    if( db2==db ){
+      pRet = pVTable;
+      p->u.vtab.p = pRet;
+      pRet->pNext = 0;
+    }else{
+      pVTable->pNext = db2->pDisconnect;
+      db2->pDisconnect = pVTable;
+    }
+    pVTable = pNext;
+  }
+
+  assert( !db || pRet );
+  return pRet;
+}
+
+/*
+** Table *p is a virtual table. This function removes the VTable object
+** for table *p associated with database connection db from the linked
+** list in p->pVTab. It also decrements the VTable ref count. This is
+** used when closing database connection db to free all of its VTable
+** objects without disturbing the rest of the Schema object (which may
+** be being used by other shared-cache connections).
+*/
+SQLITE_PRIVATE void sqlite3VtabDisconnect(sqlite3 *db, Table *p){
+  VTable **ppVTab;
+
+  assert( IsVirtual(p) );
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  for(ppVTab=&p->u.vtab.p; *ppVTab; ppVTab=&(*ppVTab)->pNext){
+    if( (*ppVTab)->db==db  ){
+      VTable *pVTab = *ppVTab;
+      *ppVTab = pVTab->pNext;
+      sqlite3VtabUnlock(pVTab);
+      break;
+    }
+  }
+}
+
+
+/*
+** Disconnect all the virtual table objects in the sqlite3.pDisconnect list.
+**
+** This function may only be called when the mutexes associated with all
+** shared b-tree databases opened using connection db are held by the
+** caller. This is done to protect the sqlite3.pDisconnect list. The
+** sqlite3.pDisconnect list is accessed only as follows:
+**
+**   1) By this function. In this case, all BtShared mutexes and the mutex
+**      associated with the database handle itself must be held.
+**
+**   2) By function vtabDisconnectAll(), when it adds a VTable entry to
+**      the sqlite3.pDisconnect list. In this case either the BtShared mutex
+**      associated with the database the virtual table is stored in is held
+**      or, if the virtual table is stored in a non-sharable database, then
+**      the database handle mutex is held.
+**
+** As a result, a sqlite3.pDisconnect cannot be accessed simultaneously
+** by multiple threads. It is thread-safe.
+*/
+SQLITE_PRIVATE void sqlite3VtabUnlockList(sqlite3 *db){
+  VTable *p = db->pDisconnect;
+
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  if( p ){
+    db->pDisconnect = 0;
+    do {
+      VTable *pNext = p->pNext;
+      sqlite3VtabUnlock(p);
+      p = pNext;
+    }while( p );
+  }
+}
+
+/*
+** Clear any and all virtual-table information from the Table record.
+** This routine is called, for example, just before deleting the Table
+** record.
+**
+** Since it is a virtual-table, the Table structure contains a pointer
+** to the head of a linked list of VTable structures. Each VTable
+** structure is associated with a single sqlite3* user of the schema.
+** The reference count of the VTable structure associated with database
+** connection db is decremented immediately (which may lead to the
+** structure being xDisconnected and free). Any other VTable structures
+** in the list are moved to the sqlite3.pDisconnect list of the associated
+** database connection.
+*/
+SQLITE_PRIVATE void sqlite3VtabClear(sqlite3 *db, Table *p){
+  assert( IsVirtual(p) );
+  assert( db!=0 );
+  if( db->pnBytesFreed==0 ) vtabDisconnectAll(0, p);
+  if( p->u.vtab.azArg ){
+    int i;
+    for(i=0; i<p->u.vtab.nArg; i++){
+      if( i!=1 ) sqlite3DbFree(db, p->u.vtab.azArg[i]);
+    }
+    sqlite3DbFree(db, p->u.vtab.azArg);
+  }
+}
+
+/*
+** Add a new module argument to pTable->u.vtab.azArg[].
+** The string is not copied - the pointer is stored.  The
+** string will be freed automatically when the table is
+** deleted.
+*/
+static void addModuleArgument(Parse *pParse, Table *pTable, char *zArg){
+  sqlite3_int64 nBytes;
+  char **azModuleArg;
+  sqlite3 *db = pParse->db;
+
+  assert( IsVirtual(pTable) );
+  nBytes = sizeof(char *)*(2+pTable->u.vtab.nArg);
+  if( pTable->u.vtab.nArg+3>=db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many columns on %s", pTable->zName);
+  }
+  azModuleArg = sqlite3DbRealloc(db, pTable->u.vtab.azArg, nBytes);
+  if( azModuleArg==0 ){
+    sqlite3DbFree(db, zArg);
+  }else{
+    int i = pTable->u.vtab.nArg++;
+    azModuleArg[i] = zArg;
+    azModuleArg[i+1] = 0;
+    pTable->u.vtab.azArg = azModuleArg;
+  }
+}
+
+/*
+** The parser calls this routine when it first sees a CREATE VIRTUAL TABLE
+** statement.  The module name has been parsed, but the optional list
+** of parameters that follow the module name are still pending.
+*/
+SQLITE_PRIVATE void sqlite3VtabBeginParse(
+  Parse *pParse,        /* Parsing context */
+  Token *pName1,        /* Name of new table, or database name */
+  Token *pName2,        /* Name of new table or NULL */
+  Token *pModuleName,   /* Name of the module for the virtual table */
+  int ifNotExists       /* No error if the table already exists */
+){
+  Table *pTable;        /* The new virtual table */
+  sqlite3 *db;          /* Database connection */
+
+  sqlite3StartTable(pParse, pName1, pName2, 0, 0, 1, ifNotExists);
+  pTable = pParse->pNewTable;
+  if( pTable==0 ) return;
+  assert( 0==pTable->pIndex );
+  pTable->eTabType = TABTYP_VTAB;
+
+  db = pParse->db;
+
+  assert( pTable->u.vtab.nArg==0 );
+  addModuleArgument(pParse, pTable, sqlite3NameFromToken(db, pModuleName));
+  addModuleArgument(pParse, pTable, 0);
+  addModuleArgument(pParse, pTable, sqlite3DbStrDup(db, pTable->zName));
+  assert( (pParse->sNameToken.z==pName2->z && pName2->z!=0)
+       || (pParse->sNameToken.z==pName1->z && pName2->z==0)
+  );
+  pParse->sNameToken.n = (int)(
+      &pModuleName->z[pModuleName->n] - pParse->sNameToken.z
+  );
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Creating a virtual table invokes the authorization callback twice.
+  ** The first invocation, to obtain permission to INSERT a row into the
+  ** sqlite_schema table, has already been made by sqlite3StartTable().
+  ** The second call, to obtain permission to create the table, is made now.
+  */
+  if( pTable->u.vtab.azArg ){
+    int iDb = sqlite3SchemaToIndex(db, pTable->pSchema);
+    assert( iDb>=0 ); /* The database the table is being created in */
+    sqlite3AuthCheck(pParse, SQLITE_CREATE_VTABLE, pTable->zName,
+            pTable->u.vtab.azArg[0], pParse->db->aDb[iDb].zDbSName);
+  }
+#endif
+}
+
+/*
+** This routine takes the module argument that has been accumulating
+** in pParse->zArg[] and appends it to the list of arguments on the
+** virtual table currently under construction in pParse->pTable.
+*/
+static void addArgumentToVtab(Parse *pParse){
+  if( pParse->sArg.z && pParse->pNewTable ){
+    const char *z = (const char*)pParse->sArg.z;
+    int n = pParse->sArg.n;
+    sqlite3 *db = pParse->db;
+    addModuleArgument(pParse, pParse->pNewTable, sqlite3DbStrNDup(db, z, n));
+  }
+}
+
+/*
+** The parser calls this routine after the CREATE VIRTUAL TABLE statement
+** has been completely parsed.
+*/
+SQLITE_PRIVATE void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){
+  Table *pTab = pParse->pNewTable;  /* The table being constructed */
+  sqlite3 *db = pParse->db;         /* The database connection */
+
+  if( pTab==0 ) return;
+  assert( IsVirtual(pTab) );
+  addArgumentToVtab(pParse);
+  pParse->sArg.z = 0;
+  if( pTab->u.vtab.nArg<1 ) return;
+
+  /* If the CREATE VIRTUAL TABLE statement is being entered for the
+  ** first time (in other words if the virtual table is actually being
+  ** created now instead of just being read out of sqlite_schema) then
+  ** do additional initialization work and store the statement text
+  ** in the sqlite_schema table.
+  */
+  if( !db->init.busy ){
+    char *zStmt;
+    char *zWhere;
+    int iDb;
+    int iReg;
+    Vdbe *v;
+
+    sqlite3MayAbort(pParse);
+
+    /* Compute the complete text of the CREATE VIRTUAL TABLE statement */
+    if( pEnd ){
+      pParse->sNameToken.n = (int)(pEnd->z - pParse->sNameToken.z) + pEnd->n;
+    }
+    zStmt = sqlite3MPrintf(db, "CREATE VIRTUAL TABLE %T", &pParse->sNameToken);
+
+    /* A slot for the record has already been allocated in the
+    ** schema table.  We just need to update that slot with all
+    ** the information we've collected.
+    **
+    ** The VM register number pParse->regRowid holds the rowid of an
+    ** entry in the sqlite_schema table that was created for this vtab
+    ** by sqlite3StartTable().
+    */
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    sqlite3NestedParse(pParse,
+      "UPDATE %Q." LEGACY_SCHEMA_TABLE " "
+         "SET type='table', name=%Q, tbl_name=%Q, rootpage=0, sql=%Q "
+       "WHERE rowid=#%d",
+      db->aDb[iDb].zDbSName,
+      pTab->zName,
+      pTab->zName,
+      zStmt,
+      pParse->regRowid
+    );
+    v = sqlite3GetVdbe(pParse);
+    sqlite3ChangeCookie(pParse, iDb);
+
+    sqlite3VdbeAddOp0(v, OP_Expire);
+    zWhere = sqlite3MPrintf(db, "name=%Q AND sql=%Q", pTab->zName, zStmt);
+    sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere, 0);
+    sqlite3DbFree(db, zStmt);
+
+    iReg = ++pParse->nMem;
+    sqlite3VdbeLoadString(v, iReg, pTab->zName);
+    sqlite3VdbeAddOp2(v, OP_VCreate, iDb, iReg);
+  }else{
+    /* If we are rereading the sqlite_schema table create the in-memory
+    ** record of the table. */
+    Table *pOld;
+    Schema *pSchema = pTab->pSchema;
+    const char *zName = pTab->zName;
+    assert( zName!=0 );
+    sqlite3MarkAllShadowTablesOf(db, pTab);
+    pOld = sqlite3HashInsert(&pSchema->tblHash, zName, pTab);
+    if( pOld ){
+      sqlite3OomFault(db);
+      assert( pTab==pOld );  /* Malloc must have failed inside HashInsert() */
+      return;
+    }
+    pParse->pNewTable = 0;
+  }
+}
+
+/*
+** The parser calls this routine when it sees the first token
+** of an argument to the module name in a CREATE VIRTUAL TABLE statement.
+*/
+SQLITE_PRIVATE void sqlite3VtabArgInit(Parse *pParse){
+  addArgumentToVtab(pParse);
+  pParse->sArg.z = 0;
+  pParse->sArg.n = 0;
+}
+
+/*
+** The parser calls this routine for each token after the first token
+** in an argument to the module name in a CREATE VIRTUAL TABLE statement.
+*/
+SQLITE_PRIVATE void sqlite3VtabArgExtend(Parse *pParse, Token *p){
+  Token *pArg = &pParse->sArg;
+  if( pArg->z==0 ){
+    pArg->z = p->z;
+    pArg->n = p->n;
+  }else{
+    assert(pArg->z <= p->z);
+    pArg->n = (int)(&p->z[p->n] - pArg->z);
+  }
+}
+
+/*
+** Invoke a virtual table constructor (either xCreate or xConnect). The
+** pointer to the function to invoke is passed as the fourth parameter
+** to this procedure.
+*/
+static int vtabCallConstructor(
+  sqlite3 *db,
+  Table *pTab,
+  Module *pMod,
+  int (*xConstruct)(sqlite3*,void*,int,const char*const*,sqlite3_vtab**,char**),
+  char **pzErr
+){
+  VtabCtx sCtx;
+  VTable *pVTable;
+  int rc;
+  const char *const*azArg;
+  int nArg = pTab->u.vtab.nArg;
+  char *zErr = 0;
+  char *zModuleName;
+  int iDb;
+  VtabCtx *pCtx;
+
+  assert( IsVirtual(pTab) );
+  azArg = (const char *const*)pTab->u.vtab.azArg;
+
+  /* Check that the virtual-table is not already being initialized */
+  for(pCtx=db->pVtabCtx; pCtx; pCtx=pCtx->pPrior){
+    if( pCtx->pTab==pTab ){
+      *pzErr = sqlite3MPrintf(db,
+          "vtable constructor called recursively: %s", pTab->zName
+      );
+      return SQLITE_LOCKED;
+    }
+  }
+
+  zModuleName = sqlite3DbStrDup(db, pTab->zName);
+  if( !zModuleName ){
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  pVTable = sqlite3MallocZero(sizeof(VTable));
+  if( !pVTable ){
+    sqlite3OomFault(db);
+    sqlite3DbFree(db, zModuleName);
+    return SQLITE_NOMEM_BKPT;
+  }
+  pVTable->db = db;
+  pVTable->pMod = pMod;
+  pVTable->eVtabRisk = SQLITE_VTABRISK_Normal;
+
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  pTab->u.vtab.azArg[1] = db->aDb[iDb].zDbSName;
+
+  /* Invoke the virtual table constructor */
+  assert( &db->pVtabCtx );
+  assert( xConstruct );
+  sCtx.pTab = pTab;
+  sCtx.pVTable = pVTable;
+  sCtx.pPrior = db->pVtabCtx;
+  sCtx.bDeclared = 0;
+  db->pVtabCtx = &sCtx;
+  pTab->nTabRef++;
+  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVTable->pVtab, &zErr);
+  assert( pTab!=0 );
+  assert( pTab->nTabRef>1 || rc!=SQLITE_OK );
+  sqlite3DeleteTable(db, pTab);
+  db->pVtabCtx = sCtx.pPrior;
+  if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
+  assert( sCtx.pTab==pTab );
+
+  if( SQLITE_OK!=rc ){
+    if( zErr==0 ){
+      *pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName);
+    }else {
+      *pzErr = sqlite3MPrintf(db, "%s", zErr);
+      sqlite3_free(zErr);
+    }
+    sqlite3DbFree(db, pVTable);
+  }else if( ALWAYS(pVTable->pVtab) ){
+    /* Justification of ALWAYS():  A correct vtab constructor must allocate
+    ** the sqlite3_vtab object if successful.  */
+    memset(pVTable->pVtab, 0, sizeof(pVTable->pVtab[0]));
+    pVTable->pVtab->pModule = pMod->pModule;
+    pMod->nRefModule++;
+    pVTable->nRef = 1;
+    if( sCtx.bDeclared==0 ){
+      const char *zFormat = "vtable constructor did not declare schema: %s";
+      *pzErr = sqlite3MPrintf(db, zFormat, zModuleName);
+      sqlite3VtabUnlock(pVTable);
+      rc = SQLITE_ERROR;
+    }else{
+      int iCol;
+      u16 oooHidden = 0;
+      /* If everything went according to plan, link the new VTable structure
+      ** into the linked list headed by pTab->u.vtab.p. Then loop through the
+      ** columns of the table to see if any of them contain the token "hidden".
+      ** If so, set the Column COLFLAG_HIDDEN flag and remove the token from
+      ** the type string.  */
+      pVTable->pNext = pTab->u.vtab.p;
+      pTab->u.vtab.p = pVTable;
+
+      for(iCol=0; iCol<pTab->nCol; iCol++){
+        char *zType = sqlite3ColumnType(&pTab->aCol[iCol], "");
+        int nType;
+        int i = 0;
+        nType = sqlite3Strlen30(zType);
+        for(i=0; i<nType; i++){
+          if( 0==sqlite3StrNICmp("hidden", &zType[i], 6)
+           && (i==0 || zType[i-1]==' ')
+           && (zType[i+6]=='\0' || zType[i+6]==' ')
+          ){
+            break;
+          }
+        }
+        if( i<nType ){
+          int j;
+          int nDel = 6 + (zType[i+6] ? 1 : 0);
+          for(j=i; (j+nDel)<=nType; j++){
+            zType[j] = zType[j+nDel];
+          }
+          if( zType[i]=='\0' && i>0 ){
+            assert(zType[i-1]==' ');
+            zType[i-1] = '\0';
+          }
+          pTab->aCol[iCol].colFlags |= COLFLAG_HIDDEN;
+          pTab->tabFlags |= TF_HasHidden;
+          oooHidden = TF_OOOHidden;
+        }else{
+          pTab->tabFlags |= oooHidden;
+        }
+      }
+    }
+  }
+
+  sqlite3DbFree(db, zModuleName);
+  return rc;
+}
+
+/*
+** This function is invoked by the parser to call the xConnect() method
+** of the virtual table pTab. If an error occurs, an error code is returned
+** and an error left in pParse.
+**
+** This call is a no-op if table pTab is not a virtual table.
+*/
+SQLITE_PRIVATE int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
+  sqlite3 *db = pParse->db;
+  const char *zMod;
+  Module *pMod;
+  int rc;
+
+  assert( pTab );
+  assert( IsVirtual(pTab) );
+  if( sqlite3GetVTable(db, pTab) ){
+    return SQLITE_OK;
+  }
+
+  /* Locate the required virtual table module */
+  zMod = pTab->u.vtab.azArg[0];
+  pMod = (Module*)sqlite3HashFind(&db->aModule, zMod);
+
+  if( !pMod ){
+    const char *zModule = pTab->u.vtab.azArg[0];
+    sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
+    rc = SQLITE_ERROR;
+  }else{
+    char *zErr = 0;
+    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xConnect, &zErr);
+    if( rc!=SQLITE_OK ){
+      sqlite3ErrorMsg(pParse, "%s", zErr);
+      pParse->rc = rc;
+    }
+    sqlite3DbFree(db, zErr);
+  }
+
+  return rc;
+}
+/*
+** Grow the db->aVTrans[] array so that there is room for at least one
+** more v-table. Return SQLITE_NOMEM if a malloc fails, or SQLITE_OK otherwise.
+*/
+static int growVTrans(sqlite3 *db){
+  const int ARRAY_INCR = 5;
+
+  /* Grow the sqlite3.aVTrans array if required */
+  if( (db->nVTrans%ARRAY_INCR)==0 ){
+    VTable **aVTrans;
+    sqlite3_int64 nBytes = sizeof(sqlite3_vtab*)*
+                                 ((sqlite3_int64)db->nVTrans + ARRAY_INCR);
+    aVTrans = sqlite3DbRealloc(db, (void *)db->aVTrans, nBytes);
+    if( !aVTrans ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    memset(&aVTrans[db->nVTrans], 0, sizeof(sqlite3_vtab *)*ARRAY_INCR);
+    db->aVTrans = aVTrans;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Add the virtual table pVTab to the array sqlite3.aVTrans[]. Space should
+** have already been reserved using growVTrans().
+*/
+static void addToVTrans(sqlite3 *db, VTable *pVTab){
+  /* Add pVtab to the end of sqlite3.aVTrans */
+  db->aVTrans[db->nVTrans++] = pVTab;
+  sqlite3VtabLock(pVTab);
+}
+
+/*
+** This function is invoked by the vdbe to call the xCreate method
+** of the virtual table named zTab in database iDb.
+**
+** If an error occurs, *pzErr is set to point to an English language
+** description of the error and an SQLITE_XXX error code is returned.
+** In this case the caller must call sqlite3DbFree(db, ) on *pzErr.
+*/
+SQLITE_PRIVATE int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab, char **pzErr){
+  int rc = SQLITE_OK;
+  Table *pTab;
+  Module *pMod;
+  const char *zMod;
+
+  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zDbSName);
+  assert( pTab && IsVirtual(pTab) && !pTab->u.vtab.p );
+
+  /* Locate the required virtual table module */
+  zMod = pTab->u.vtab.azArg[0];
+  pMod = (Module*)sqlite3HashFind(&db->aModule, zMod);
+
+  /* If the module has been registered and includes a Create method,
+  ** invoke it now. If the module has not been registered, return an
+  ** error. Otherwise, do nothing.
+  */
+  if( pMod==0 || pMod->pModule->xCreate==0 || pMod->pModule->xDestroy==0 ){
+    *pzErr = sqlite3MPrintf(db, "no such module: %s", zMod);
+    rc = SQLITE_ERROR;
+  }else{
+    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
+  }
+
+  /* Justification of ALWAYS():  The xConstructor method is required to
+  ** create a valid sqlite3_vtab if it returns SQLITE_OK. */
+  if( rc==SQLITE_OK && ALWAYS(sqlite3GetVTable(db, pTab)) ){
+    rc = growVTrans(db);
+    if( rc==SQLITE_OK ){
+      addToVTrans(db, sqlite3GetVTable(db, pTab));
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is used to set the schema of a virtual table.  It is only
+** valid to call this function from within the xCreate() or xConnect() of a
+** virtual table module.
+*/
+SQLITE_API int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){
+  VtabCtx *pCtx;
+  int rc = SQLITE_OK;
+  Table *pTab;
+  Parse sParse;
+  int initBusy;
+  int i;
+  const unsigned char *z;
+  static const u8 aKeyword[] = { TK_CREATE, TK_TABLE, 0 };
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zCreateTable==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+
+  /* Verify that the first two keywords in the CREATE TABLE statement
+  ** really are "CREATE" and "TABLE".  If this is not the case, then
+  ** sqlite3_declare_vtab() is being misused.
+  */
+  z = (const unsigned char*)zCreateTable;
+  for(i=0; aKeyword[i]; i++){
+    int tokenType = 0;
+    do{
+      z += sqlite3GetToken(z, &tokenType);
+    }while( tokenType==TK_SPACE || tokenType==TK_COMMENT );
+    if( tokenType!=aKeyword[i] ){
+      sqlite3ErrorWithMsg(db, SQLITE_ERROR, "syntax error");
+      return SQLITE_ERROR;
+    }
+  }
+
+  sqlite3_mutex_enter(db->mutex);
+  pCtx = db->pVtabCtx;
+  if( !pCtx || pCtx->bDeclared ){
+    sqlite3Error(db, SQLITE_MISUSE_BKPT);
+    sqlite3_mutex_leave(db->mutex);
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  pTab = pCtx->pTab;
+  assert( IsVirtual(pTab) );
+
+  sqlite3ParseObjectInit(&sParse, db);
+  sParse.eParseMode = PARSE_MODE_DECLARE_VTAB;
+  sParse.disableTriggers = 1;
+  /* We should never be able to reach this point while loading the
+  ** schema.  Nevertheless, defend against that (turn off db->init.busy)
+  ** in case a bug arises. */
+  assert( db->init.busy==0 );
+  initBusy = db->init.busy;
+  db->init.busy = 0;
+  sParse.nQueryLoop = 1;
+  if( SQLITE_OK==sqlite3RunParser(&sParse, zCreateTable) ){
+    assert( sParse.pNewTable!=0 );
+    assert( !db->mallocFailed );
+    assert( IsOrdinaryTable(sParse.pNewTable) );
+    assert( sParse.zErrMsg==0 );
+    if( !pTab->aCol ){
+      Table *pNew = sParse.pNewTable;
+      Index *pIdx;
+      pTab->aCol = pNew->aCol;
+      assert( IsOrdinaryTable(pNew) );
+      sqlite3ExprListDelete(db, pNew->u.tab.pDfltList);
+      pTab->nNVCol = pTab->nCol = pNew->nCol;
+      pTab->tabFlags |= pNew->tabFlags & (TF_WithoutRowid|TF_NoVisibleRowid);
+      pNew->nCol = 0;
+      pNew->aCol = 0;
+      assert( pTab->pIndex==0 );
+      assert( HasRowid(pNew) || sqlite3PrimaryKeyIndex(pNew)!=0 );
+      if( !HasRowid(pNew)
+       && pCtx->pVTable->pMod->pModule->xUpdate!=0
+       && sqlite3PrimaryKeyIndex(pNew)->nKeyCol!=1
+      ){
+        /* WITHOUT ROWID virtual tables must either be read-only (xUpdate==0)
+        ** or else must have a single-column PRIMARY KEY */
+        rc = SQLITE_ERROR;
+      }
+      pIdx = pNew->pIndex;
+      if( pIdx ){
+        assert( pIdx->pNext==0 );
+        pTab->pIndex = pIdx;
+        pNew->pIndex = 0;
+        pIdx->pTable = pTab;
+      }
+    }
+    pCtx->bDeclared = 1;
+  }else{
+    sqlite3ErrorWithMsg(db, SQLITE_ERROR,
+          (sParse.zErrMsg ? "%s" : 0), sParse.zErrMsg);
+    sqlite3DbFree(db, sParse.zErrMsg);
+    rc = SQLITE_ERROR;
+  }
+  sParse.eParseMode = PARSE_MODE_NORMAL;
+
+  if( sParse.pVdbe ){
+    sqlite3VdbeFinalize(sParse.pVdbe);
+  }
+  sqlite3DeleteTable(db, sParse.pNewTable);
+  sqlite3ParseObjectReset(&sParse);
+  db->init.busy = initBusy;
+
+  assert( (rc&0xff)==rc );
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** This function is invoked by the vdbe to call the xDestroy method
+** of the virtual table named zTab in database iDb. This occurs
+** when a DROP TABLE is mentioned.
+**
+** This call is a no-op if zTab is not a virtual table.
+*/
+SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab){
+  int rc = SQLITE_OK;
+  Table *pTab;
+
+  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zDbSName);
+  if( ALWAYS(pTab!=0)
+   && ALWAYS(IsVirtual(pTab))
+   && ALWAYS(pTab->u.vtab.p!=0)
+  ){
+    VTable *p;
+    int (*xDestroy)(sqlite3_vtab *);
+    for(p=pTab->u.vtab.p; p; p=p->pNext){
+      assert( p->pVtab );
+      if( p->pVtab->nRef>0 ){
+        return SQLITE_LOCKED;
+      }
+    }
+    p = vtabDisconnectAll(db, pTab);
+    xDestroy = p->pMod->pModule->xDestroy;
+    if( xDestroy==0 ) xDestroy = p->pMod->pModule->xDisconnect;
+    assert( xDestroy!=0 );
+    pTab->nTabRef++;
+    rc = xDestroy(p->pVtab);
+    /* Remove the sqlite3_vtab* from the aVTrans[] array, if applicable */
+    if( rc==SQLITE_OK ){
+      assert( pTab->u.vtab.p==p && p->pNext==0 );
+      p->pVtab = 0;
+      pTab->u.vtab.p = 0;
+      sqlite3VtabUnlock(p);
+    }
+    sqlite3DeleteTable(db, pTab);
+  }
+
+  return rc;
+}
+
+/*
+** This function invokes either the xRollback or xCommit method
+** of each of the virtual tables in the sqlite3.aVTrans array. The method
+** called is identified by the second argument, "offset", which is
+** the offset of the method to call in the sqlite3_module structure.
+**
+** The array is cleared after invoking the callbacks.
+*/
+static void callFinaliser(sqlite3 *db, int offset){
+  int i;
+  if( db->aVTrans ){
+    VTable **aVTrans = db->aVTrans;
+    db->aVTrans = 0;
+    for(i=0; i<db->nVTrans; i++){
+      VTable *pVTab = aVTrans[i];
+      sqlite3_vtab *p = pVTab->pVtab;
+      if( p ){
+        int (*x)(sqlite3_vtab *);
+        x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset);
+        if( x ) x(p);
+      }
+      pVTab->iSavepoint = 0;
+      sqlite3VtabUnlock(pVTab);
+    }
+    sqlite3DbFree(db, aVTrans);
+    db->nVTrans = 0;
+  }
+}
+
+/*
+** Invoke the xSync method of all virtual tables in the sqlite3.aVTrans
+** array. Return the error code for the first error that occurs, or
+** SQLITE_OK if all xSync operations are successful.
+**
+** If an error message is available, leave it in p->zErrMsg.
+*/
+SQLITE_PRIVATE int sqlite3VtabSync(sqlite3 *db, Vdbe *p){
+  int i;
+  int rc = SQLITE_OK;
+  VTable **aVTrans = db->aVTrans;
+
+  db->aVTrans = 0;
+  for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){
+    int (*x)(sqlite3_vtab *);
+    sqlite3_vtab *pVtab = aVTrans[i]->pVtab;
+    if( pVtab && (x = pVtab->pModule->xSync)!=0 ){
+      rc = x(pVtab);
+      sqlite3VtabImportErrmsg(p, pVtab);
+    }
+  }
+  db->aVTrans = aVTrans;
+  return rc;
+}
+
+/*
+** Invoke the xRollback method of all virtual tables in the
+** sqlite3.aVTrans array. Then clear the array itself.
+*/
+SQLITE_PRIVATE int sqlite3VtabRollback(sqlite3 *db){
+  callFinaliser(db, offsetof(sqlite3_module,xRollback));
+  return SQLITE_OK;
+}
+
+/*
+** Invoke the xCommit method of all virtual tables in the
+** sqlite3.aVTrans array. Then clear the array itself.
+*/
+SQLITE_PRIVATE int sqlite3VtabCommit(sqlite3 *db){
+  callFinaliser(db, offsetof(sqlite3_module,xCommit));
+  return SQLITE_OK;
+}
+
+/*
+** If the virtual table pVtab supports the transaction interface
+** (xBegin/xRollback/xCommit and optionally xSync) and a transaction is
+** not currently open, invoke the xBegin method now.
+**
+** If the xBegin call is successful, place the sqlite3_vtab pointer
+** in the sqlite3.aVTrans array.
+*/
+SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *db, VTable *pVTab){
+  int rc = SQLITE_OK;
+  const sqlite3_module *pModule;
+
+  /* Special case: If db->aVTrans is NULL and db->nVTrans is greater
+  ** than zero, then this function is being called from within a
+  ** virtual module xSync() callback. It is illegal to write to
+  ** virtual module tables in this case, so return SQLITE_LOCKED.
+  */
+  if( sqlite3VtabInSync(db) ){
+    return SQLITE_LOCKED;
+  }
+  if( !pVTab ){
+    return SQLITE_OK;
+  }
+  pModule = pVTab->pVtab->pModule;
+
+  if( pModule->xBegin ){
+    int i;
+
+    /* If pVtab is already in the aVTrans array, return early */
+    for(i=0; i<db->nVTrans; i++){
+      if( db->aVTrans[i]==pVTab ){
+        return SQLITE_OK;
+      }
+    }
+
+    /* Invoke the xBegin method. If successful, add the vtab to the
+    ** sqlite3.aVTrans[] array. */
+    rc = growVTrans(db);
+    if( rc==SQLITE_OK ){
+      rc = pModule->xBegin(pVTab->pVtab);
+      if( rc==SQLITE_OK ){
+        int iSvpt = db->nStatement + db->nSavepoint;
+        addToVTrans(db, pVTab);
+        if( iSvpt && pModule->xSavepoint ){
+          pVTab->iSavepoint = iSvpt;
+          rc = pModule->xSavepoint(pVTab->pVtab, iSvpt-1);
+        }
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Invoke either the xSavepoint, xRollbackTo or xRelease method of all
+** virtual tables that currently have an open transaction. Pass iSavepoint
+** as the second argument to the virtual table method invoked.
+**
+** If op is SAVEPOINT_BEGIN, the xSavepoint method is invoked. If it is
+** SAVEPOINT_ROLLBACK, the xRollbackTo method. Otherwise, if op is
+** SAVEPOINT_RELEASE, then the xRelease method of each virtual table with
+** an open transaction is invoked.
+**
+** If any virtual table method returns an error code other than SQLITE_OK,
+** processing is abandoned and the error returned to the caller of this
+** function immediately. If all calls to virtual table methods are successful,
+** SQLITE_OK is returned.
+*/
+SQLITE_PRIVATE int sqlite3VtabSavepoint(sqlite3 *db, int op, int iSavepoint){
+  int rc = SQLITE_OK;
+
+  assert( op==SAVEPOINT_RELEASE||op==SAVEPOINT_ROLLBACK||op==SAVEPOINT_BEGIN );
+  assert( iSavepoint>=-1 );
+  if( db->aVTrans ){
+    int i;
+    for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){
+      VTable *pVTab = db->aVTrans[i];
+      const sqlite3_module *pMod = pVTab->pMod->pModule;
+      if( pVTab->pVtab && pMod->iVersion>=2 ){
+        int (*xMethod)(sqlite3_vtab *, int);
+        sqlite3VtabLock(pVTab);
+        switch( op ){
+          case SAVEPOINT_BEGIN:
+            xMethod = pMod->xSavepoint;
+            pVTab->iSavepoint = iSavepoint+1;
+            break;
+          case SAVEPOINT_ROLLBACK:
+            xMethod = pMod->xRollbackTo;
+            break;
+          default:
+            xMethod = pMod->xRelease;
+            break;
+        }
+        if( xMethod && pVTab->iSavepoint>iSavepoint ){
+          u64 savedFlags = (db->flags & SQLITE_Defensive);
+          db->flags &= ~(u64)SQLITE_Defensive;
+          rc = xMethod(pVTab->pVtab, iSavepoint);
+          db->flags |= savedFlags;
+        }
+        sqlite3VtabUnlock(pVTab);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** The first parameter (pDef) is a function implementation.  The
+** second parameter (pExpr) is the first argument to this function.
+** If pExpr is a column in a virtual table, then let the virtual
+** table implementation have an opportunity to overload the function.
+**
+** This routine is used to allow virtual table implementations to
+** overload MATCH, LIKE, GLOB, and REGEXP operators.
+**
+** Return either the pDef argument (indicating no change) or a
+** new FuncDef structure that is marked as ephemeral using the
+** SQLITE_FUNC_EPHEM flag.
+*/
+SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(
+  sqlite3 *db,    /* Database connection for reporting malloc problems */
+  FuncDef *pDef,  /* Function to possibly overload */
+  int nArg,       /* Number of arguments to the function */
+  Expr *pExpr     /* First argument to the function */
+){
+  Table *pTab;
+  sqlite3_vtab *pVtab;
+  sqlite3_module *pMod;
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value**) = 0;
+  void *pArg = 0;
+  FuncDef *pNew;
+  int rc = 0;
+
+  /* Check to see the left operand is a column in a virtual table */
+  if( NEVER(pExpr==0) ) return pDef;
+  if( pExpr->op!=TK_COLUMN ) return pDef;
+  assert( ExprUseYTab(pExpr) );
+  pTab = pExpr->y.pTab;
+  if( NEVER(pTab==0) ) return pDef;
+  if( !IsVirtual(pTab) ) return pDef;
+  pVtab = sqlite3GetVTable(db, pTab)->pVtab;
+  assert( pVtab!=0 );
+  assert( pVtab->pModule!=0 );
+  pMod = (sqlite3_module *)pVtab->pModule;
+  if( pMod->xFindFunction==0 ) return pDef;
+
+  /* Call the xFindFunction method on the virtual table implementation
+  ** to see if the implementation wants to overload this function.
+  **
+  ** Though undocumented, we have historically always invoked xFindFunction
+  ** with an all lower-case function name.  Continue in this tradition to
+  ** avoid any chance of an incompatibility.
+  */
+#ifdef SQLITE_DEBUG
+  {
+    int i;
+    for(i=0; pDef->zName[i]; i++){
+      unsigned char x = (unsigned char)pDef->zName[i];
+      assert( x==sqlite3UpperToLower[x] );
+    }
+  }
+#endif
+  rc = pMod->xFindFunction(pVtab, nArg, pDef->zName, &xSFunc, &pArg);
+  if( rc==0 ){
+    return pDef;
+  }
+
+  /* Create a new ephemeral function definition for the overloaded
+  ** function */
+  pNew = sqlite3DbMallocZero(db, sizeof(*pNew)
+                             + sqlite3Strlen30(pDef->zName) + 1);
+  if( pNew==0 ){
+    return pDef;
+  }
+  *pNew = *pDef;
+  pNew->zName = (const char*)&pNew[1];
+  memcpy((char*)&pNew[1], pDef->zName, sqlite3Strlen30(pDef->zName)+1);
+  pNew->xSFunc = xSFunc;
+  pNew->pUserData = pArg;
+  pNew->funcFlags |= SQLITE_FUNC_EPHEM;
+  return pNew;
+}
+
+/*
+** Make sure virtual table pTab is contained in the pParse->apVirtualLock[]
+** array so that an OP_VBegin will get generated for it.  Add pTab to the
+** array if it is missing.  If pTab is already in the array, this routine
+** is a no-op.
+*/
+SQLITE_PRIVATE void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  int i, n;
+  Table **apVtabLock;
+
+  assert( IsVirtual(pTab) );
+  for(i=0; i<pToplevel->nVtabLock; i++){
+    if( pTab==pToplevel->apVtabLock[i] ) return;
+  }
+  n = (pToplevel->nVtabLock+1)*sizeof(pToplevel->apVtabLock[0]);
+  apVtabLock = sqlite3Realloc(pToplevel->apVtabLock, n);
+  if( apVtabLock ){
+    pToplevel->apVtabLock = apVtabLock;
+    pToplevel->apVtabLock[pToplevel->nVtabLock++] = pTab;
+  }else{
+    sqlite3OomFault(pToplevel->db);
+  }
+}
+
+/*
+** Check to see if virtual table module pMod can be have an eponymous
+** virtual table instance.  If it can, create one if one does not already
+** exist. Return non-zero if either the eponymous virtual table instance
+** exists when this routine returns or if an attempt to create it failed
+** and an error message was left in pParse.
+**
+** An eponymous virtual table instance is one that is named after its
+** module, and more importantly, does not require a CREATE VIRTUAL TABLE
+** statement in order to come into existence.  Eponymous virtual table
+** instances always exist.  They cannot be DROP-ed.
+**
+** Any virtual table module for which xConnect and xCreate are the same
+** method can have an eponymous virtual table instance.
+*/
+SQLITE_PRIVATE int sqlite3VtabEponymousTableInit(Parse *pParse, Module *pMod){
+  const sqlite3_module *pModule = pMod->pModule;
+  Table *pTab;
+  char *zErr = 0;
+  int rc;
+  sqlite3 *db = pParse->db;
+  if( pMod->pEpoTab ) return 1;
+  if( pModule->xCreate!=0 && pModule->xCreate!=pModule->xConnect ) return 0;
+  pTab = sqlite3DbMallocZero(db, sizeof(Table));
+  if( pTab==0 ) return 0;
+  pTab->zName = sqlite3DbStrDup(db, pMod->zName);
+  if( pTab->zName==0 ){
+    sqlite3DbFree(db, pTab);
+    return 0;
+  }
+  pMod->pEpoTab = pTab;
+  pTab->nTabRef = 1;
+  pTab->eTabType = TABTYP_VTAB;
+  pTab->pSchema = db->aDb[0].pSchema;
+  assert( pTab->u.vtab.nArg==0 );
+  pTab->iPKey = -1;
+  pTab->tabFlags |= TF_Eponymous;
+  addModuleArgument(pParse, pTab, sqlite3DbStrDup(db, pTab->zName));
+  addModuleArgument(pParse, pTab, 0);
+  addModuleArgument(pParse, pTab, sqlite3DbStrDup(db, pTab->zName));
+  rc = vtabCallConstructor(db, pTab, pMod, pModule->xConnect, &zErr);
+  if( rc ){
+    sqlite3ErrorMsg(pParse, "%s", zErr);
+    sqlite3DbFree(db, zErr);
+    sqlite3VtabEponymousTableClear(db, pMod);
+  }
+  return 1;
+}
+
+/*
+** Erase the eponymous virtual table instance associated with
+** virtual table module pMod, if it exists.
+*/
+SQLITE_PRIVATE void sqlite3VtabEponymousTableClear(sqlite3 *db, Module *pMod){
+  Table *pTab = pMod->pEpoTab;
+  if( pTab!=0 ){
+    /* Mark the table as Ephemeral prior to deleting it, so that the
+    ** sqlite3DeleteTable() routine will know that it is not stored in
+    ** the schema. */
+    pTab->tabFlags |= TF_Ephemeral;
+    sqlite3DeleteTable(db, pTab);
+    pMod->pEpoTab = 0;
+  }
+}
+
+/*
+** Return the ON CONFLICT resolution mode in effect for the virtual
+** table update operation currently in progress.
+**
+** The results of this routine are undefined unless it is called from
+** within an xUpdate method.
+*/
+SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *db){
+  static const unsigned char aMap[] = {
+    SQLITE_ROLLBACK, SQLITE_ABORT, SQLITE_FAIL, SQLITE_IGNORE, SQLITE_REPLACE
+  };
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  assert( OE_Rollback==1 && OE_Abort==2 && OE_Fail==3 );
+  assert( OE_Ignore==4 && OE_Replace==5 );
+  assert( db->vtabOnConflict>=1 && db->vtabOnConflict<=5 );
+  return (int)aMap[db->vtabOnConflict-1];
+}
+
+/*
+** Call from within the xCreate() or xConnect() methods to provide
+** the SQLite core with additional information about the behavior
+** of the virtual table being implemented.
+*/
+SQLITE_API int sqlite3_vtab_config(sqlite3 *db, int op, ...){
+  va_list ap;
+  int rc = SQLITE_OK;
+  VtabCtx *p;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  p = db->pVtabCtx;
+  if( !p ){
+    rc = SQLITE_MISUSE_BKPT;
+  }else{
+    assert( p->pTab==0 || IsVirtual(p->pTab) );
+    va_start(ap, op);
+    switch( op ){
+      case SQLITE_VTAB_CONSTRAINT_SUPPORT: {
+        p->pVTable->bConstraint = (u8)va_arg(ap, int);
+        break;
+      }
+      case SQLITE_VTAB_INNOCUOUS: {
+        p->pVTable->eVtabRisk = SQLITE_VTABRISK_Low;
+        break;
+      }
+      case SQLITE_VTAB_DIRECTONLY: {
+        p->pVTable->eVtabRisk = SQLITE_VTABRISK_High;
+        break;
+      }
+      case SQLITE_VTAB_USES_ALL_SCHEMAS: {
+        p->pVTable->bAllSchemas = 1;
+        break;
+      }
+      default: {
+        rc = SQLITE_MISUSE_BKPT;
+        break;
+      }
+    }
+    va_end(ap);
+  }
+
+  if( rc!=SQLITE_OK ) sqlite3Error(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/************** End of vtab.c ************************************************/
+/************** Begin file wherecode.c ***************************************/
+/*
+** 2015-06-06
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This module contains C code that generates VDBE code used to process
+** the WHERE clause of SQL statements.
+**
+** This file was split off from where.c on 2015-06-06 in order to reduce the
+** size of where.c and make it easier to edit.  This file contains the routines
+** that actually generate the bulk of the WHERE loop code.  The original where.c
+** file retains the code that does query planning and analysis.
+*/
+/* #include "sqliteInt.h" */
+/************** Include whereInt.h in the middle of wherecode.c **************/
+/************** Begin file whereInt.h ****************************************/
+/*
+** 2013-11-12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains structure and macro definitions for the query
+** planner logic in "where.c".  These definitions are broken out into
+** a separate source file for easier editing.
+*/
+#ifndef SQLITE_WHEREINT_H
+#define SQLITE_WHEREINT_H
+
+
+/* Forward references
+*/
+typedef struct WhereClause WhereClause;
+typedef struct WhereMaskSet WhereMaskSet;
+typedef struct WhereOrInfo WhereOrInfo;
+typedef struct WhereAndInfo WhereAndInfo;
+typedef struct WhereLevel WhereLevel;
+typedef struct WhereLoop WhereLoop;
+typedef struct WherePath WherePath;
+typedef struct WhereTerm WhereTerm;
+typedef struct WhereLoopBuilder WhereLoopBuilder;
+typedef struct WhereScan WhereScan;
+typedef struct WhereOrCost WhereOrCost;
+typedef struct WhereOrSet WhereOrSet;
+typedef struct WhereMemBlock WhereMemBlock;
+typedef struct WhereRightJoin WhereRightJoin;
+
+/*
+** This object is a header on a block of allocated memory that will be
+** automatically freed when its WInfo object is destructed.
+*/
+struct WhereMemBlock {
+  WhereMemBlock *pNext;      /* Next block in the chain */
+  u64 sz;                    /* Bytes of space */
+};
+
+/*
+** Extra information attached to a WhereLevel that is a RIGHT JOIN.
+*/
+struct WhereRightJoin {
+  int iMatch;          /* Cursor used to determine prior matched rows */
+  int regBloom;        /* Bloom filter for iRJMatch */
+  int regReturn;       /* Return register for the interior subroutine */
+  int addrSubrtn;      /* Starting address for the interior subroutine */
+  int endSubrtn;       /* The last opcode in the interior subroutine */
+};
+
+/*
+** This object contains information needed to implement a single nested
+** loop in WHERE clause.
+**
+** Contrast this object with WhereLoop.  This object describes the
+** implementation of the loop.  WhereLoop describes the algorithm.
+** This object contains a pointer to the WhereLoop algorithm as one of
+** its elements.
+**
+** The WhereInfo object contains a single instance of this object for
+** each term in the FROM clause (which is to say, for each of the
+** nested loops as implemented).  The order of WhereLevel objects determines
+** the loop nested order, with WhereInfo.a[0] being the outer loop and
+** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop.
+*/
+struct WhereLevel {
+  int iLeftJoin;        /* Memory cell used to implement LEFT OUTER JOIN */
+  int iTabCur;          /* The VDBE cursor used to access the table */
+  int iIdxCur;          /* The VDBE cursor used to access pIdx */
+  int addrBrk;          /* Jump here to break out of the loop */
+  int addrNxt;          /* Jump here to start the next IN combination */
+  int addrSkip;         /* Jump here for next iteration of skip-scan */
+  int addrCont;         /* Jump here to continue with the next loop cycle */
+  int addrFirst;        /* First instruction of interior of the loop */
+  int addrBody;         /* Beginning of the body of this loop */
+  int regBignull;       /* big-null flag reg. True if a NULL-scan is needed */
+  int addrBignull;      /* Jump here for next part of big-null scan */
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+  u32 iLikeRepCntr;     /* LIKE range processing counter register (times 2) */
+  int addrLikeRep;      /* LIKE range processing address */
+#endif
+  int regFilter;        /* Bloom filter */
+  WhereRightJoin *pRJ;  /* Extra information for RIGHT JOIN */
+  u8 iFrom;             /* Which entry in the FROM clause */
+  u8 op, p3, p5;        /* Opcode, P3 & P5 of the opcode that ends the loop */
+  int p1, p2;           /* Operands of the opcode used to end the loop */
+  union {               /* Information that depends on pWLoop->wsFlags */
+    struct {
+      int nIn;              /* Number of entries in aInLoop[] */
+      struct InLoop {
+        int iCur;              /* The VDBE cursor used by this IN operator */
+        int addrInTop;         /* Top of the IN loop */
+        int iBase;             /* Base register of multi-key index record */
+        int nPrefix;           /* Number of prior entries in the key */
+        u8 eEndLoopOp;         /* IN Loop terminator. OP_Next or OP_Prev */
+      } *aInLoop;           /* Information about each nested IN operator */
+    } in;                 /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */
+    Index *pCoveringIdx;  /* Possible covering index for WHERE_MULTI_OR */
+  } u;
+  struct WhereLoop *pWLoop;  /* The selected WhereLoop object */
+  Bitmask notReady;          /* FROM entries not usable at this level */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrVisit;        /* Address at which row is visited */
+#endif
+};
+
+/*
+** Each instance of this object represents an algorithm for evaluating one
+** term of a join.  Every term of the FROM clause will have at least
+** one corresponding WhereLoop object (unless INDEXED BY constraints
+** prevent a query solution - which is an error) and many terms of the
+** FROM clause will have multiple WhereLoop objects, each describing a
+** potential way of implementing that FROM-clause term, together with
+** dependencies and cost estimates for using the chosen algorithm.
+**
+** Query planning consists of building up a collection of these WhereLoop
+** objects, then computing a particular sequence of WhereLoop objects, with
+** one WhereLoop object per FROM clause term, that satisfy all dependencies
+** and that minimize the overall cost.
+*/
+struct WhereLoop {
+  Bitmask prereq;       /* Bitmask of other loops that must run first */
+  Bitmask maskSelf;     /* Bitmask identifying table iTab */
+#ifdef SQLITE_DEBUG
+  char cId;             /* Symbolic ID of this loop for debugging use */
+#endif
+  u8 iTab;              /* Position in FROM clause of table for this loop */
+  u8 iSortIdx;          /* Sorting index number.  0==None */
+  LogEst rSetup;        /* One-time setup cost (ex: create transient index) */
+  LogEst rRun;          /* Cost of running each loop */
+  LogEst nOut;          /* Estimated number of output rows */
+  union {
+    struct {               /* Information for internal btree tables */
+      u16 nEq;               /* Number of equality constraints */
+      u16 nBtm;              /* Size of BTM vector */
+      u16 nTop;              /* Size of TOP vector */
+      u16 nDistinctCol;      /* Index columns used to sort for DISTINCT */
+      Index *pIndex;         /* Index used, or NULL */
+      ExprList *pOrderBy;    /* ORDER BY clause if this is really a subquery */
+    } btree;
+    struct {               /* Information for virtual tables */
+      int idxNum;            /* Index number */
+      u32 needFree : 1;      /* True if sqlite3_free(idxStr) is needed */
+      u32 bOmitOffset : 1;   /* True to let virtual table handle offset */
+      u32 bIdxNumHex : 1;    /* Show idxNum as hex in EXPLAIN QUERY PLAN */
+      i8 isOrdered;          /* True if satisfies ORDER BY */
+      u16 omitMask;          /* Terms that may be omitted */
+      char *idxStr;          /* Index identifier string */
+      u32 mHandleIn;         /* Terms to handle as IN(...) instead of == */
+    } vtab;
+  } u;
+  u32 wsFlags;          /* WHERE_* flags describing the plan */
+  u16 nLTerm;           /* Number of entries in aLTerm[] */
+  u16 nSkip;            /* Number of NULL aLTerm[] entries */
+  /**** whereLoopXfer() copies fields above ***********************/
+# define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot)
+  u16 nLSlot;           /* Number of slots allocated for aLTerm[] */
+#ifdef WHERETRACE_ENABLED
+  LogEst rStarDelta;    /* Cost delta due to star-schema heuristic.  Not
+                        ** initialized unless pWInfo->bStarUsed */
+#endif
+  WhereTerm **aLTerm;   /* WhereTerms used */
+  WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */
+  WhereTerm *aLTermSpace[3];  /* Initial aLTerm[] space */
+};
+
+/* This object holds the prerequisites and the cost of running a
+** subquery on one operand of an OR operator in the WHERE clause.
+** See WhereOrSet for additional information
+*/
+struct WhereOrCost {
+  Bitmask prereq;     /* Prerequisites */
+  LogEst rRun;        /* Cost of running this subquery */
+  LogEst nOut;        /* Number of outputs for this subquery */
+};
+
+/* The WhereOrSet object holds a set of possible WhereOrCosts that
+** correspond to the subquery(s) of OR-clause processing.  Only the
+** best N_OR_COST elements are retained.
+*/
+#define N_OR_COST 3
+struct WhereOrSet {
+  u16 n;                      /* Number of valid a[] entries */
+  WhereOrCost a[N_OR_COST];   /* Set of best costs */
+};
+
+/*
+** Each instance of this object holds a sequence of WhereLoop objects
+** that implement some or all of a query plan.
+**
+** Think of each WhereLoop object as a node in a graph with arcs
+** showing dependencies and costs for travelling between nodes.  (That is
+** not a completely accurate description because WhereLoop costs are a
+** vector, not a scalar, and because dependencies are many-to-one, not
+** one-to-one as are graph nodes.  But it is a useful visualization aid.)
+** Then a WherePath object is a path through the graph that visits some
+** or all of the WhereLoop objects once.
+**
+** The "solver" works by creating the N best WherePath objects of length
+** 1.  Then using those as a basis to compute the N best WherePath objects
+** of length 2.  And so forth until the length of WherePaths equals the
+** number of nodes in the FROM clause.  The best (lowest cost) WherePath
+** at the end is the chosen query plan.
+*/
+struct WherePath {
+  Bitmask maskLoop;     /* Bitmask of all WhereLoop objects in this path */
+  Bitmask revLoop;      /* aLoop[]s that should be reversed for ORDER BY */
+  LogEst nRow;          /* Estimated number of rows generated by this path */
+  LogEst rCost;         /* Total cost of this path */
+  LogEst rUnsort;       /* Total cost of this path ignoring sorting costs */
+  i8 isOrdered;         /* No. of ORDER BY terms satisfied. -1 for unknown */
+  WhereLoop **aLoop;    /* Array of WhereLoop objects implementing this path */
+};
+
+/*
+** The query generator uses an array of instances of this structure to
+** help it analyze the subexpressions of the WHERE clause.  Each WHERE
+** clause subexpression is separated from the others by AND operators,
+** usually, or sometimes subexpressions separated by OR.
+**
+** All WhereTerms are collected into a single WhereClause structure.
+** The following identity holds:
+**
+**        WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm
+**
+** When a term is of the form:
+**
+**              X <op> <expr>
+**
+** where X is a column name and <op> is one of certain operators,
+** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the
+** cursor number and column number for X.  WhereTerm.eOperator records
+** the <op> using a bitmask encoding defined by WO_xxx below.  The
+** use of a bitmask encoding for the operator allows us to search
+** quickly for terms that match any of several different operators.
+**
+** A WhereTerm might also be two or more subterms connected by OR:
+**
+**         (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR ....
+**
+** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR
+** and the WhereTerm.u.pOrInfo field points to auxiliary information that
+** is collected about the OR clause.
+**
+** If a term in the WHERE clause does not match either of the two previous
+** categories, then eOperator==0.  The WhereTerm.pExpr field is still set
+** to the original subexpression content and wtFlags is set up appropriately
+** but no other fields in the WhereTerm object are meaningful.
+**
+** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers,
+** but they do so indirectly.  A single WhereMaskSet structure translates
+** cursor number into bits and the translated bit is stored in the prereq
+** fields.  The translation is used in order to maximize the number of
+** bits that will fit in a Bitmask.  The VDBE cursor numbers might be
+** spread out over the non-negative integers.  For example, the cursor
+** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45.  The WhereMaskSet
+** translates these sparse cursor numbers into consecutive integers
+** beginning with 0 in order to make the best possible use of the available
+** bits in the Bitmask.  So, in the example above, the cursor numbers
+** would be mapped into integers 0 through 7.
+**
+** The number of terms in a join is limited by the number of bits
+** in prereqRight and prereqAll.  The default is 64 bits, hence SQLite
+** is only able to process joins with 64 or fewer tables.
+*/
+struct WhereTerm {
+  Expr *pExpr;            /* Pointer to the subexpression that is this term */
+  WhereClause *pWC;       /* The clause this term is part of */
+  LogEst truthProb;       /* Probability of truth for this expression */
+  u16 wtFlags;            /* TERM_xxx bit flags.  See below */
+  u16 eOperator;          /* A WO_xx value describing <op> */
+  u8 nChild;              /* Number of children that must disable us */
+  u8 eMatchOp;            /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */
+  int iParent;            /* Disable pWC->a[iParent] when this term disabled */
+  int leftCursor;         /* Cursor number of X in "X <op> <expr>" */
+  union {
+    struct {
+      int leftColumn;         /* Column number of X in "X <op> <expr>" */
+      int iField;             /* Field in (?,?,?) IN (SELECT...) vector */
+    } x;                    /* Opcode other than OP_OR or OP_AND */
+    WhereOrInfo *pOrInfo;   /* Extra information if (eOperator & WO_OR)!=0 */
+    WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */
+  } u;
+  Bitmask prereqRight;    /* Bitmask of tables used by pExpr->pRight */
+  Bitmask prereqAll;      /* Bitmask of tables referenced by pExpr */
+};
+
+/*
+** Allowed values of WhereTerm.wtFlags
+*/
+#define TERM_DYNAMIC    0x0001 /* Need to call sqlite3ExprDelete(db, pExpr) */
+#define TERM_VIRTUAL    0x0002 /* Added by the optimizer.  Do not code */
+#define TERM_CODED      0x0004 /* This term is already coded */
+#define TERM_COPIED     0x0008 /* Has a child */
+#define TERM_ORINFO     0x0010 /* Need to free the WhereTerm.u.pOrInfo object */
+#define TERM_ANDINFO    0x0020 /* Need to free the WhereTerm.u.pAndInfo obj */
+#define TERM_OK         0x0040 /* Used during OR-clause processing */
+#define TERM_VNULL      0x0080 /* Manufactured x>NULL or x<=NULL term */
+#define TERM_LIKEOPT    0x0100 /* Virtual terms from the LIKE optimization */
+#define TERM_LIKECOND   0x0200 /* Conditionally this LIKE operator term */
+#define TERM_LIKE       0x0400 /* The original LIKE operator */
+#define TERM_IS         0x0800 /* Term.pExpr is an IS operator */
+#define TERM_VARSELECT  0x1000 /* Term.pExpr contains a correlated sub-query */
+#define TERM_HEURTRUTH  0x2000 /* Heuristic truthProb used */
+#ifdef SQLITE_ENABLE_STAT4
+#  define TERM_HIGHTRUTH  0x4000 /* Term excludes few rows */
+#else
+#  define TERM_HIGHTRUTH  0      /* Only used with STAT4 */
+#endif
+#define TERM_SLICE      0x8000 /* One slice of a row-value/vector comparison */
+
+/*
+** An instance of the WhereScan object is used as an iterator for locating
+** terms in the WHERE clause that are useful to the query planner.
+*/
+struct WhereScan {
+  WhereClause *pOrigWC;      /* Original, innermost WhereClause */
+  WhereClause *pWC;          /* WhereClause currently being scanned */
+  const char *zCollName;     /* Required collating sequence, if not NULL */
+  Expr *pIdxExpr;            /* Search for this index expression */
+  int k;                     /* Resume scanning at this->pWC->a[this->k] */
+  u32 opMask;                /* Acceptable operators */
+  char idxaff;               /* Must match this affinity, if zCollName!=NULL */
+  unsigned char iEquiv;      /* Current slot in aiCur[] and aiColumn[] */
+  unsigned char nEquiv;      /* Number of entries in aiCur[] and aiColumn[] */
+  int aiCur[11];             /* Cursors in the equivalence class */
+  i16 aiColumn[11];          /* Corresponding column number in the eq-class */
+};
+
+/*
+** An instance of the following structure holds all information about a
+** WHERE clause.  Mostly this is a container for one or more WhereTerms.
+**
+** Explanation of pOuter:  For a WHERE clause of the form
+**
+**           a AND ((b AND c) OR (d AND e)) AND f
+**
+** There are separate WhereClause objects for the whole clause and for
+** the subclauses "(b AND c)" and "(d AND e)".  The pOuter field of the
+** subclauses points to the WhereClause object for the whole clause.
+*/
+struct WhereClause {
+  WhereInfo *pWInfo;       /* WHERE clause processing context */
+  WhereClause *pOuter;     /* Outer conjunction */
+  u8 op;                   /* Split operator.  TK_AND or TK_OR */
+  u8 hasOr;                /* True if any a[].eOperator is WO_OR */
+  int nTerm;               /* Number of terms */
+  int nSlot;               /* Number of entries in a[] */
+  int nBase;               /* Number of terms through the last non-Virtual */
+  WhereTerm *a;            /* Each a[] describes a term of the WHERE clause */
+#if defined(SQLITE_SMALL_STACK)
+  WhereTerm aStatic[1];    /* Initial static space for a[] */
+#else
+  WhereTerm aStatic[8];    /* Initial static space for a[] */
+#endif
+};
+
+/*
+** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to
+** a dynamically allocated instance of the following structure.
+*/
+struct WhereOrInfo {
+  WhereClause wc;          /* Decomposition into subterms */
+  Bitmask indexable;       /* Bitmask of all indexable tables in the clause */
+};
+
+/*
+** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to
+** a dynamically allocated instance of the following structure.
+*/
+struct WhereAndInfo {
+  WhereClause wc;          /* The subexpression broken out */
+};
+
+/*
+** An instance of the following structure keeps track of a mapping
+** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
+**
+** The VDBE cursor numbers are small integers contained in
+** SrcItem.iCursor and Expr.iTable fields.  For any given WHERE
+** clause, the cursor numbers might not begin with 0 and they might
+** contain gaps in the numbering sequence.  But we want to make maximum
+** use of the bits in our bitmasks.  This structure provides a mapping
+** from the sparse cursor numbers into consecutive integers beginning
+** with 0.
+**
+** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask
+** corresponds VDBE cursor number B.  The A-th bit of a bitmask is 1<<A.
+**
+** For example, if the WHERE clause expression used these VDBE
+** cursors:  4, 5, 8, 29, 57, 73.  Then the  WhereMaskSet structure
+** would map those cursor numbers into bits 0 through 5.
+**
+** Note that the mapping is not necessarily ordered.  In the example
+** above, the mapping might go like this:  4->3, 5->1, 8->2, 29->0,
+** 57->5, 73->4.  Or one of 719 other combinations might be used. It
+** does not really matter.  What is important is that sparse cursor
+** numbers all get mapped into bit numbers that begin with 0 and contain
+** no gaps.
+*/
+struct WhereMaskSet {
+  int bVarSelect;               /* Used by sqlite3WhereExprUsage() */
+  int n;                        /* Number of assigned cursor values */
+  int ix[BMS];                  /* Cursor assigned to each bit */
+};
+
+/*
+** This object is a convenience wrapper holding all information needed
+** to construct WhereLoop objects for a particular query.
+*/
+struct WhereLoopBuilder {
+  WhereInfo *pWInfo;        /* Information about this WHERE */
+  WhereClause *pWC;         /* WHERE clause terms */
+  WhereLoop *pNew;          /* Template WhereLoop */
+  WhereOrSet *pOrSet;       /* Record best loops here, if not NULL */
+#ifdef SQLITE_ENABLE_STAT4
+  UnpackedRecord *pRec;     /* Probe for stat4 (if required) */
+  int nRecValid;            /* Number of valid fields currently in pRec */
+#endif
+  unsigned char bldFlags1;  /* First set of SQLITE_BLDF_* flags */
+  unsigned char bldFlags2;  /* Second set of SQLITE_BLDF_* flags */
+  unsigned int iPlanLimit;  /* Search limiter */
+};
+
+/* Allowed values for WhereLoopBuider.bldFlags */
+#define SQLITE_BLDF1_INDEXED  0x0001   /* An index is used */
+#define SQLITE_BLDF1_UNIQUE   0x0002   /* All keys of a UNIQUE index used */
+
+#define SQLITE_BLDF2_2NDPASS  0x0004   /* Second builder pass needed */
+
+/* The WhereLoopBuilder.iPlanLimit is used to limit the number of
+** index+constraint combinations the query planner will consider for a
+** particular query.  If this parameter is unlimited, then certain
+** pathological queries can spend excess time in the sqlite3WhereBegin()
+** routine.  The limit is high enough that is should not impact real-world
+** queries.
+**
+** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit.  The limit is
+** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM
+** clause is processed, so that every table in a join is guaranteed to be
+** able to propose a some index+constraint combinations even if the initial
+** baseline limit was exhausted by prior tables of the join.
+*/
+#ifndef SQLITE_QUERY_PLANNER_LIMIT
+# define SQLITE_QUERY_PLANNER_LIMIT 20000
+#endif
+#ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR
+# define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000
+#endif
+
+/*
+** The WHERE clause processing routine has two halves.  The
+** first part does the start of the WHERE loop and the second
+** half does the tail of the WHERE loop.  An instance of
+** this structure is returned by the first half and passed
+** into the second half to give some continuity.
+**
+** An instance of this object holds the complete state of the query
+** planner.
+*/
+struct WhereInfo {
+  Parse *pParse;            /* Parsing and code generating context */
+  SrcList *pTabList;        /* List of tables in the join */
+  ExprList *pOrderBy;       /* The ORDER BY clause or NULL */
+  ExprList *pResultSet;     /* Result set of the query */
+#if WHERETRACE_ENABLED
+  Expr *pWhere;             /* The complete WHERE clause */
+#endif
+  Select *pSelect;          /* The entire SELECT statement containing WHERE */
+  int aiCurOnePass[2];      /* OP_OpenWrite cursors for the ONEPASS opt */
+  int iContinue;            /* Jump here to continue with next record */
+  int iBreak;               /* Jump here to break out of the loop */
+  int savedNQueryLoop;      /* pParse->nQueryLoop outside the WHERE loop */
+  u16 wctrlFlags;           /* Flags originally passed to sqlite3WhereBegin() */
+  LogEst iLimit;            /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */
+  u8 nLevel;                /* Number of nested loop */
+  i8 nOBSat;                /* Number of ORDER BY terms satisfied by indices */
+  u8 eOnePass;              /* ONEPASS_OFF, or _SINGLE, or _MULTI */
+  u8 eDistinct;             /* One of the WHERE_DISTINCT_* values */
+  unsigned bDeferredSeek :1;   /* Uses OP_DeferredSeek */
+  unsigned untestedTerms :1;   /* Not all WHERE terms resolved by outer loop */
+  unsigned bOrderedInnerLoop:1;/* True if only the inner-most loop is ordered */
+  unsigned sorted        :1;   /* True if really sorted (not just grouped) */
+  unsigned bStarDone     :1;   /* True if check for star-query is complete */
+  unsigned bStarUsed     :1;   /* True if star-query heuristic is used */
+  LogEst nRowOut;           /* Estimated number of output rows */
+#ifdef WHERETRACE_ENABLED
+  LogEst rTotalCost;        /* Total cost of the solution */
+#endif
+  int iTop;                 /* The very beginning of the WHERE loop */
+  int iEndWhere;            /* End of the WHERE clause itself */
+  WhereLoop *pLoops;        /* List of all WhereLoop objects */
+  WhereMemBlock *pMemToFree;/* Memory to free when this object destroyed */
+  Bitmask revMask;          /* Mask of ORDER BY terms that need reversing */
+  WhereClause sWC;          /* Decomposition of the WHERE clause */
+  WhereMaskSet sMaskSet;    /* Map cursor numbers to bitmasks */
+  WhereLevel a[1];          /* Information about each nest loop in WHERE */
+};
+
+/*
+** Private interfaces - callable only by other where.c routines.
+**
+** where.c:
+*/
+SQLITE_PRIVATE Bitmask sqlite3WhereGetMask(WhereMaskSet*,int);
+#ifdef WHERETRACE_ENABLED
+SQLITE_PRIVATE void sqlite3WhereClausePrint(WhereClause *pWC);
+SQLITE_PRIVATE void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm);
+SQLITE_PRIVATE void sqlite3WhereLoopPrint(const WhereLoop *p, const WhereClause *pWC);
+#endif
+SQLITE_PRIVATE WhereTerm *sqlite3WhereFindTerm(
+  WhereClause *pWC,     /* The WHERE clause to be searched */
+  int iCur,             /* Cursor number of LHS */
+  int iColumn,          /* Column number of LHS */
+  Bitmask notReady,     /* RHS must not overlap with this mask */
+  u32 op,               /* Mask of WO_xx values describing operator */
+  Index *pIdx           /* Must be compatible with this index, if not NULL */
+);
+SQLITE_PRIVATE void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte);
+SQLITE_PRIVATE void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte);
+
+/* wherecode.c: */
+#ifndef SQLITE_OMIT_EXPLAIN
+SQLITE_PRIVATE int sqlite3WhereExplainOneScan(
+  Parse *pParse,                  /* Parse context */
+  SrcList *pTabList,              /* Table list this loop refers to */
+  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
+  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
+);
+SQLITE_PRIVATE int sqlite3WhereExplainBloomFilter(
+  const Parse *pParse,            /* Parse context */
+  const WhereInfo *pWInfo,        /* WHERE clause */
+  const WhereLevel *pLevel        /* Bloom filter on this level */
+);
+SQLITE_PRIVATE void sqlite3WhereAddExplainText(
+  Parse *pParse,                  /* Parse context */
+  int addr,
+  SrcList *pTabList,              /* Table list this loop refers to */
+  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
+  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
+);
+#else
+# define sqlite3WhereExplainOneScan(u,v,w,x) 0
+# define sqlite3WhereExplainBloomFilter(u,v,w) 0
+# define  sqlite3WhereAddExplainText(u,v,w,x,y)
+#endif /* SQLITE_OMIT_EXPLAIN */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+SQLITE_PRIVATE void sqlite3WhereAddScanStatus(
+  Vdbe *v,                        /* Vdbe to add scanstatus entry to */
+  SrcList *pSrclist,              /* FROM clause pLvl reads data from */
+  WhereLevel *pLvl,               /* Level to add scanstatus() entry for */
+  int addrExplain                 /* Address of OP_Explain (or 0) */
+);
+#else
+# define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d)
+#endif
+SQLITE_PRIVATE Bitmask sqlite3WhereCodeOneLoopStart(
+  Parse *pParse,       /* Parsing context */
+  Vdbe *v,             /* Prepared statement under construction */
+  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
+  int iLevel,          /* Which level of pWInfo->a[] should be coded */
+  WhereLevel *pLevel,  /* The current level pointer */
+  Bitmask notReady     /* Which tables are currently available */
+);
+SQLITE_PRIVATE SQLITE_NOINLINE void sqlite3WhereRightJoinLoop(
+  WhereInfo *pWInfo,
+  int iLevel,
+  WhereLevel *pLevel
+);
+
+/* whereexpr.c: */
+SQLITE_PRIVATE void sqlite3WhereClauseInit(WhereClause*,WhereInfo*);
+SQLITE_PRIVATE void sqlite3WhereClauseClear(WhereClause*);
+SQLITE_PRIVATE void sqlite3WhereSplit(WhereClause*,Expr*,u8);
+SQLITE_PRIVATE void sqlite3WhereAddLimit(WhereClause*, Select*);
+SQLITE_PRIVATE Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*);
+SQLITE_PRIVATE Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*);
+SQLITE_PRIVATE Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*);
+SQLITE_PRIVATE void sqlite3WhereExprAnalyze(SrcList*, WhereClause*);
+SQLITE_PRIVATE void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*);
+
+
+
+
+
+/*
+** Bitmasks for the operators on WhereTerm objects.  These are all
+** operators that are of interest to the query planner.  An
+** OR-ed combination of these values can be used when searching for
+** particular WhereTerms within a WhereClause.
+**
+** Value constraints:
+**     WO_EQ    == SQLITE_INDEX_CONSTRAINT_EQ
+**     WO_LT    == SQLITE_INDEX_CONSTRAINT_LT
+**     WO_LE    == SQLITE_INDEX_CONSTRAINT_LE
+**     WO_GT    == SQLITE_INDEX_CONSTRAINT_GT
+**     WO_GE    == SQLITE_INDEX_CONSTRAINT_GE
+*/
+#define WO_IN     0x0001
+#define WO_EQ     0x0002
+#define WO_LT     (WO_EQ<<(TK_LT-TK_EQ))
+#define WO_LE     (WO_EQ<<(TK_LE-TK_EQ))
+#define WO_GT     (WO_EQ<<(TK_GT-TK_EQ))
+#define WO_GE     (WO_EQ<<(TK_GE-TK_EQ))
+#define WO_AUX    0x0040       /* Op useful to virtual tables only */
+#define WO_IS     0x0080
+#define WO_ISNULL 0x0100
+#define WO_OR     0x0200       /* Two or more OR-connected terms */
+#define WO_AND    0x0400       /* Two or more AND-connected terms */
+#define WO_EQUIV  0x0800       /* Of the form A==B, both columns */
+#define WO_NOOP   0x1000       /* This term does not restrict search space */
+#define WO_ROWVAL 0x2000       /* A row-value term */
+
+#define WO_ALL    0x3fff       /* Mask of all possible WO_* values */
+#define WO_SINGLE 0x01ff       /* Mask of all non-compound WO_* values */
+
+/*
+** These are definitions of bits in the WhereLoop.wsFlags field.
+** The particular combination of bits in each WhereLoop help to
+** determine the algorithm that WhereLoop represents.
+*/
+#define WHERE_COLUMN_EQ    0x00000001  /* x=EXPR */
+#define WHERE_COLUMN_RANGE 0x00000002  /* x<EXPR and/or x>EXPR */
+#define WHERE_COLUMN_IN    0x00000004  /* x IN (...) */
+#define WHERE_COLUMN_NULL  0x00000008  /* x IS NULL */
+#define WHERE_CONSTRAINT   0x0000000f  /* Any of the WHERE_COLUMN_xxx values */
+#define WHERE_TOP_LIMIT    0x00000010  /* x<EXPR or x<=EXPR constraint */
+#define WHERE_BTM_LIMIT    0x00000020  /* x>EXPR or x>=EXPR constraint */
+#define WHERE_BOTH_LIMIT   0x00000030  /* Both x>EXPR and x<EXPR */
+#define WHERE_IDX_ONLY     0x00000040  /* Use index only - omit table */
+#define WHERE_IPK          0x00000100  /* x is the INTEGER PRIMARY KEY */
+#define WHERE_INDEXED      0x00000200  /* WhereLoop.u.btree.pIndex is valid */
+#define WHERE_VIRTUALTABLE 0x00000400  /* WhereLoop.u.vtab is valid */
+#define WHERE_IN_ABLE      0x00000800  /* Able to support an IN operator */
+#define WHERE_ONEROW       0x00001000  /* Selects no more than one row */
+#define WHERE_MULTI_OR     0x00002000  /* OR using multiple indices */
+#define WHERE_AUTO_INDEX   0x00004000  /* Uses an ephemeral index */
+#define WHERE_SKIPSCAN     0x00008000  /* Uses the skip-scan algorithm */
+#define WHERE_UNQ_WANTED   0x00010000  /* WHERE_ONEROW would have been helpful*/
+#define WHERE_PARTIALIDX   0x00020000  /* The automatic index is partial */
+#define WHERE_IN_EARLYOUT  0x00040000  /* Perhaps quit IN loops early */
+#define WHERE_BIGNULL_SORT 0x00080000  /* Column nEq of index is BIGNULL */
+#define WHERE_IN_SEEKSCAN  0x00100000  /* Seek-scan optimization for IN */
+#define WHERE_TRANSCONS    0x00200000  /* Uses a transitive constraint */
+#define WHERE_BLOOMFILTER  0x00400000  /* Consider using a Bloom-filter */
+#define WHERE_SELFCULL     0x00800000  /* nOut reduced by extra WHERE terms */
+#define WHERE_OMIT_OFFSET  0x01000000  /* Set offset counter to zero */
+#define WHERE_COROUTINE    0x02000000  /* Implemented by co-routine.
+                                       ** NB: False-negatives are possible */
+#define WHERE_EXPRIDX      0x04000000  /* Uses an index-on-expressions */
+
+#endif /* !defined(SQLITE_WHEREINT_H) */
+
+/************** End of whereInt.h ********************************************/
+/************** Continuing where we left off in wherecode.c ******************/
+
+#ifndef SQLITE_OMIT_EXPLAIN
+
+/*
+** Return the name of the i-th column of the pIdx index.
+*/
+static const char *explainIndexColumnName(Index *pIdx, int i){
+  i = pIdx->aiColumn[i];
+  if( i==XN_EXPR ) return "<expr>";
+  if( i==XN_ROWID ) return "rowid";
+  return pIdx->pTable->aCol[i].zCnName;
+}
+
+/*
+** This routine is a helper for explainIndexRange() below
+**
+** pStr holds the text of an expression that we are building up one term
+** at a time.  This routine adds a new term to the end of the expression.
+** Terms are separated by AND so add the "AND" text for second and subsequent
+** terms only.
+*/
+static void explainAppendTerm(
+  StrAccum *pStr,             /* The text expression being built */
+  Index *pIdx,                /* Index to read column names from */
+  int nTerm,                  /* Number of terms */
+  int iTerm,                  /* Zero-based index of first term. */
+  int bAnd,                   /* Non-zero to append " AND " */
+  const char *zOp             /* Name of the operator */
+){
+  int i;
+
+  assert( nTerm>=1 );
+  if( bAnd ) sqlite3_str_append(pStr, " AND ", 5);
+
+  if( nTerm>1 ) sqlite3_str_append(pStr, "(", 1);
+  for(i=0; i<nTerm; i++){
+    if( i ) sqlite3_str_append(pStr, ",", 1);
+    sqlite3_str_appendall(pStr, explainIndexColumnName(pIdx, iTerm+i));
+  }
+  if( nTerm>1 ) sqlite3_str_append(pStr, ")", 1);
+
+  sqlite3_str_append(pStr, zOp, 1);
+
+  if( nTerm>1 ) sqlite3_str_append(pStr, "(", 1);
+  for(i=0; i<nTerm; i++){
+    if( i ) sqlite3_str_append(pStr, ",", 1);
+    sqlite3_str_append(pStr, "?", 1);
+  }
+  if( nTerm>1 ) sqlite3_str_append(pStr, ")", 1);
+}
+
+/*
+** Argument pLevel describes a strategy for scanning table pTab. This
+** function appends text to pStr that describes the subset of table
+** rows scanned by the strategy in the form of an SQL expression.
+**
+** For example, if the query:
+**
+**   SELECT * FROM t1 WHERE a=1 AND b>2;
+**
+** is run and there is an index on (a, b), then this function returns a
+** string similar to:
+**
+**   "a=? AND b>?"
+*/
+static void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop){
+  Index *pIndex = pLoop->u.btree.pIndex;
+  u16 nEq = pLoop->u.btree.nEq;
+  u16 nSkip = pLoop->nSkip;
+  int i, j;
+
+  if( nEq==0 && (pLoop->wsFlags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ) return;
+  sqlite3_str_append(pStr, " (", 2);
+  for(i=0; i<nEq; i++){
+    const char *z = explainIndexColumnName(pIndex, i);
+    if( i ) sqlite3_str_append(pStr, " AND ", 5);
+    sqlite3_str_appendf(pStr, i>=nSkip ? "%s=?" : "ANY(%s)", z);
+  }
+
+  j = i;
+  if( pLoop->wsFlags&WHERE_BTM_LIMIT ){
+    explainAppendTerm(pStr, pIndex, pLoop->u.btree.nBtm, j, i, ">");
+    i = 1;
+  }
+  if( pLoop->wsFlags&WHERE_TOP_LIMIT ){
+    explainAppendTerm(pStr, pIndex, pLoop->u.btree.nTop, j, i, "<");
+  }
+  sqlite3_str_append(pStr, ")", 1);
+}
+
+/*
+** This function sets the P4 value of an existing OP_Explain opcode to
+** text describing the loop in pLevel. If the OP_Explain opcode already has
+** a P4 value, it is freed before it is overwritten.
+*/
+SQLITE_PRIVATE void sqlite3WhereAddExplainText(
+  Parse *pParse,                  /* Parse context */
+  int addr,                       /* Address of OP_Explain opcode */
+  SrcList *pTabList,              /* Table list this loop refers to */
+  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
+  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
+){
+#if !defined(SQLITE_DEBUG)
+  if( sqlite3ParseToplevel(pParse)->explain==2 || IS_STMT_SCANSTATUS(pParse->db) )
+#endif
+  {
+    VdbeOp *pOp = sqlite3VdbeGetOp(pParse->pVdbe, addr);
+
+    SrcItem *pItem = &pTabList->a[pLevel->iFrom];
+    sqlite3 *db = pParse->db;     /* Database handle */
+    int isSearch;                 /* True for a SEARCH. False for SCAN. */
+    WhereLoop *pLoop;             /* The controlling WhereLoop object */
+    u32 flags;                    /* Flags that describe this loop */
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_EXPLAIN)
+    char *zMsg;                   /* Text to add to EQP output */
+#endif
+    StrAccum str;                 /* EQP output string */
+    char zBuf[100];               /* Initial space for EQP output string */
+
+    if( db->mallocFailed ) return;
+
+    pLoop = pLevel->pWLoop;
+    flags = pLoop->wsFlags;
+
+    isSearch = (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0
+            || ((flags&WHERE_VIRTUALTABLE)==0 && (pLoop->u.btree.nEq>0))
+            || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX));
+
+    sqlite3StrAccumInit(&str, db, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH);
+    str.printfFlags = SQLITE_PRINTF_INTERNAL;
+    sqlite3_str_appendf(&str, "%s %S", isSearch ? "SEARCH" : "SCAN", pItem);
+    if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0 ){
+      const char *zFmt = 0;
+      Index *pIdx;
+
+      assert( pLoop->u.btree.pIndex!=0 );
+      pIdx = pLoop->u.btree.pIndex;
+      assert( !(flags&WHERE_AUTO_INDEX) || (flags&WHERE_IDX_ONLY) );
+      if( !HasRowid(pItem->pSTab) && IsPrimaryKeyIndex(pIdx) ){
+        if( isSearch ){
+          zFmt = "PRIMARY KEY";
+        }
+      }else if( flags & WHERE_PARTIALIDX ){
+        zFmt = "AUTOMATIC PARTIAL COVERING INDEX";
+      }else if( flags & WHERE_AUTO_INDEX ){
+        zFmt = "AUTOMATIC COVERING INDEX";
+      }else if( flags & (WHERE_IDX_ONLY|WHERE_EXPRIDX) ){
+        zFmt = "COVERING INDEX %s";
+      }else{
+        zFmt = "INDEX %s";
+      }
+      if( zFmt ){
+        sqlite3_str_append(&str, " USING ", 7);
+        sqlite3_str_appendf(&str, zFmt, pIdx->zName);
+        explainIndexRange(&str, pLoop);
+      }
+    }else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){
+      char cRangeOp;
+#if 0  /* Better output, but breaks many tests */
+      const Table *pTab = pItem->pTab;
+      const char *zRowid = pTab->iPKey>=0 ? pTab->aCol[pTab->iPKey].zCnName:
+                              "rowid";
+#else
+      const char *zRowid = "rowid";
+#endif
+      sqlite3_str_appendf(&str, " USING INTEGER PRIMARY KEY (%s", zRowid);
+      if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){
+        cRangeOp = '=';
+      }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){
+        sqlite3_str_appendf(&str, ">? AND %s", zRowid);
+        cRangeOp = '<';
+      }else if( flags&WHERE_BTM_LIMIT ){
+        cRangeOp = '>';
+      }else{
+        assert( flags&WHERE_TOP_LIMIT);
+        cRangeOp = '<';
+      }
+      sqlite3_str_appendf(&str, "%c?)", cRangeOp);
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    else if( (flags & WHERE_VIRTUALTABLE)!=0 ){
+      sqlite3_str_appendall(&str, " VIRTUAL TABLE INDEX ");
+      sqlite3_str_appendf(&str,
+                  pLoop->u.vtab.bIdxNumHex ? "0x%x:%s" : "%d:%s",
+                  pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr);
+    }
+#endif
+    if( pItem->fg.jointype & JT_LEFT ){
+      sqlite3_str_appendf(&str, " LEFT-JOIN");
+    }
+#ifdef SQLITE_EXPLAIN_ESTIMATED_ROWS
+    if( pLoop->nOut>=10 ){
+      sqlite3_str_appendf(&str, " (~%llu rows)",
+             sqlite3LogEstToInt(pLoop->nOut));
+    }else{
+      sqlite3_str_append(&str, " (~1 row)", 9);
+    }
+#endif
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_EXPLAIN)
+    zMsg = sqlite3StrAccumFinish(&str);
+    sqlite3ExplainBreakpoint("",zMsg);
+#endif
+
+    assert( pOp->opcode==OP_Explain );
+    assert( pOp->p4type==P4_DYNAMIC || pOp->p4.z==0 );
+    sqlite3DbFree(db, pOp->p4.z);
+    pOp->p4type = P4_DYNAMIC;
+    pOp->p4.z = sqlite3StrAccumFinish(&str);
+  }
+}
+
+
+/*
+** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN
+** command, or if stmt_scanstatus_v2() stats are enabled, or if SQLITE_DEBUG
+** was defined at compile-time. If it is not a no-op, a single OP_Explain
+** opcode is added to the output to describe the table scan strategy in pLevel.
+**
+** If an OP_Explain opcode is added to the VM, its address is returned.
+** Otherwise, if no OP_Explain is coded, zero is returned.
+*/
+SQLITE_PRIVATE int sqlite3WhereExplainOneScan(
+  Parse *pParse,                  /* Parse context */
+  SrcList *pTabList,              /* Table list this loop refers to */
+  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
+  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
+){
+  int ret = 0;
+#if !defined(SQLITE_DEBUG)
+  if( sqlite3ParseToplevel(pParse)->explain==2 || IS_STMT_SCANSTATUS(pParse->db) )
+#endif
+  {
+    if( (pLevel->pWLoop->wsFlags & WHERE_MULTI_OR)==0
+     && (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
+    ){
+      Vdbe *v = pParse->pVdbe;
+      int addr = sqlite3VdbeCurrentAddr(v);
+      ret = sqlite3VdbeAddOp3(
+          v, OP_Explain, addr, pParse->addrExplain, pLevel->pWLoop->rRun
+      );
+      sqlite3WhereAddExplainText(pParse, addr, pTabList, pLevel, wctrlFlags);
+    }
+  }
+  return ret;
+}
+
+/*
+** Add a single OP_Explain opcode that describes a Bloom filter.
+**
+** Or if not processing EXPLAIN QUERY PLAN and not in a SQLITE_DEBUG and/or
+** SQLITE_ENABLE_STMT_SCANSTATUS build, then OP_Explain opcodes are not
+** required and this routine is a no-op.
+**
+** If an OP_Explain opcode is added to the VM, its address is returned.
+** Otherwise, if no OP_Explain is coded, zero is returned.
+*/
+SQLITE_PRIVATE int sqlite3WhereExplainBloomFilter(
+  const Parse *pParse,               /* Parse context */
+  const WhereInfo *pWInfo,           /* WHERE clause */
+  const WhereLevel *pLevel           /* Bloom filter on this level */
+){
+  int ret = 0;
+  SrcItem *pItem = &pWInfo->pTabList->a[pLevel->iFrom];
+  Vdbe *v = pParse->pVdbe;      /* VM being constructed */
+  sqlite3 *db = pParse->db;     /* Database handle */
+  char *zMsg;                   /* Text to add to EQP output */
+  int i;                        /* Loop counter */
+  WhereLoop *pLoop;             /* The where loop */
+  StrAccum str;                 /* EQP output string */
+  char zBuf[100];               /* Initial space for EQP output string */
+
+  sqlite3StrAccumInit(&str, db, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH);
+  str.printfFlags = SQLITE_PRINTF_INTERNAL;
+  sqlite3_str_appendf(&str, "BLOOM FILTER ON %S (", pItem);
+  pLoop = pLevel->pWLoop;
+  if( pLoop->wsFlags & WHERE_IPK ){
+    const Table *pTab = pItem->pSTab;
+    if( pTab->iPKey>=0 ){
+      sqlite3_str_appendf(&str, "%s=?", pTab->aCol[pTab->iPKey].zCnName);
+    }else{
+      sqlite3_str_appendf(&str, "rowid=?");
+    }
+  }else{
+    for(i=pLoop->nSkip; i<pLoop->u.btree.nEq; i++){
+      const char *z = explainIndexColumnName(pLoop->u.btree.pIndex, i);
+      if( i>pLoop->nSkip ) sqlite3_str_append(&str, " AND ", 5);
+      sqlite3_str_appendf(&str, "%s=?", z);
+    }
+  }
+  sqlite3_str_append(&str, ")", 1);
+  zMsg = sqlite3StrAccumFinish(&str);
+  ret = sqlite3VdbeAddOp4(v, OP_Explain, sqlite3VdbeCurrentAddr(v),
+                          pParse->addrExplain, 0, zMsg,P4_DYNAMIC);
+
+  sqlite3VdbeScanStatus(v, sqlite3VdbeCurrentAddr(v)-1, 0, 0, 0, 0);
+  return ret;
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+/*
+** Configure the VM passed as the first argument with an
+** sqlite3_stmt_scanstatus() entry corresponding to the scan used to
+** implement level pLvl. Argument pSrclist is a pointer to the FROM
+** clause that the scan reads data from.
+**
+** If argument addrExplain is not 0, it must be the address of an
+** OP_Explain instruction that describes the same loop.
+*/
+SQLITE_PRIVATE void sqlite3WhereAddScanStatus(
+  Vdbe *v,                        /* Vdbe to add scanstatus entry to */
+  SrcList *pSrclist,              /* FROM clause pLvl reads data from */
+  WhereLevel *pLvl,               /* Level to add scanstatus() entry for */
+  int addrExplain                 /* Address of OP_Explain (or 0) */
+){
+  if( IS_STMT_SCANSTATUS( sqlite3VdbeDb(v) ) ){
+    const char *zObj = 0;
+    WhereLoop *pLoop = pLvl->pWLoop;
+    int wsFlags = pLoop->wsFlags;
+    int viaCoroutine = 0;
+
+    if( (wsFlags & WHERE_VIRTUALTABLE)==0  &&  pLoop->u.btree.pIndex!=0 ){
+      zObj = pLoop->u.btree.pIndex->zName;
+    }else{
+      zObj = pSrclist->a[pLvl->iFrom].zName;
+      viaCoroutine = pSrclist->a[pLvl->iFrom].fg.viaCoroutine;
+    }
+    sqlite3VdbeScanStatus(
+        v, addrExplain, pLvl->addrBody, pLvl->addrVisit, pLoop->nOut, zObj
+    );
+
+    if( viaCoroutine==0 ){
+      if( (wsFlags & (WHERE_MULTI_OR|WHERE_AUTO_INDEX))==0 ){
+        sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iTabCur);
+      }
+      if( wsFlags & WHERE_INDEXED ){
+        sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iIdxCur);
+      }
+    }else{
+      int addr;
+      VdbeOp *pOp;
+      assert( pSrclist->a[pLvl->iFrom].fg.isSubquery );
+      addr = pSrclist->a[pLvl->iFrom].u4.pSubq->addrFillSub;
+      pOp = sqlite3VdbeGetOp(v, addr-1);
+      assert( sqlite3VdbeDb(v)->mallocFailed || pOp->opcode==OP_InitCoroutine );
+      assert( sqlite3VdbeDb(v)->mallocFailed || pOp->p2>addr );
+      sqlite3VdbeScanStatusRange(v, addrExplain, addr, pOp->p2-1);
+    }
+  }
+}
+#endif
+
+
+/*
+** Disable a term in the WHERE clause.  Except, do not disable the term
+** if it controls a LEFT OUTER JOIN and it did not originate in the ON
+** or USING clause of that join.
+**
+** Consider the term t2.z='ok' in the following queries:
+**
+**   (1)  SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x WHERE t2.z='ok'
+**   (2)  SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x AND t2.z='ok'
+**   (3)  SELECT * FROM t1, t2 WHERE t1.a=t2.x AND t2.z='ok'
+**
+** The t2.z='ok' is disabled in the in (2) because it originates
+** in the ON clause.  The term is disabled in (3) because it is not part
+** of a LEFT OUTER JOIN.  In (1), the term is not disabled.
+**
+** Disabling a term causes that term to not be tested in the inner loop
+** of the join.  Disabling is an optimization.  When terms are satisfied
+** by indices, we disable them to prevent redundant tests in the inner
+** loop.  We would get the correct results if nothing were ever disabled,
+** but joins might run a little slower.  The trick is to disable as much
+** as we can without disabling too much.  If we disabled in (1), we'd get
+** the wrong answer.  See ticket #813.
+**
+** If all the children of a term are disabled, then that term is also
+** automatically disabled.  In this way, terms get disabled if derived
+** virtual terms are tested first.  For example:
+**
+**      x GLOB 'abc*' AND x>='abc' AND x<'acd'
+**      \___________/     \______/     \_____/
+**         parent          child1       child2
+**
+** Only the parent term was in the original WHERE clause.  The child1
+** and child2 terms were added by the LIKE optimization.  If both of
+** the virtual child terms are valid, then testing of the parent can be
+** skipped.
+**
+** Usually the parent term is marked as TERM_CODED.  But if the parent
+** term was originally TERM_LIKE, then the parent gets TERM_LIKECOND instead.
+** The TERM_LIKECOND marking indicates that the term should be coded inside
+** a conditional such that is only evaluated on the second pass of a
+** LIKE-optimization loop, when scanning BLOBs instead of strings.
+*/
+static void disableTerm(WhereLevel *pLevel, WhereTerm *pTerm){
+  int nLoop = 0;
+  assert( pTerm!=0 );
+  while( (pTerm->wtFlags & TERM_CODED)==0
+      && (pLevel->iLeftJoin==0 || ExprHasProperty(pTerm->pExpr, EP_OuterON))
+      && (pLevel->notReady & pTerm->prereqAll)==0
+  ){
+    if( nLoop && (pTerm->wtFlags & TERM_LIKE)!=0 ){
+      pTerm->wtFlags |= TERM_LIKECOND;
+    }else{
+      pTerm->wtFlags |= TERM_CODED;
+    }
+#ifdef WHERETRACE_ENABLED
+    if( (sqlite3WhereTrace & 0x4001)==0x4001 ){
+      sqlite3DebugPrintf("DISABLE-");
+      sqlite3WhereTermPrint(pTerm, (int)(pTerm - (pTerm->pWC->a)));
+    }
+#endif
+    if( pTerm->iParent<0 ) break;
+    pTerm = &pTerm->pWC->a[pTerm->iParent];
+    assert( pTerm!=0 );
+    pTerm->nChild--;
+    if( pTerm->nChild!=0 ) break;
+    nLoop++;
+  }
+}
+
+/*
+** Code an OP_Affinity opcode to apply the column affinity string zAff
+** to the n registers starting at base.
+**
+** As an optimization, SQLITE_AFF_BLOB and SQLITE_AFF_NONE entries (which
+** are no-ops) at the beginning and end of zAff are ignored.  If all entries
+** in zAff are SQLITE_AFF_BLOB or SQLITE_AFF_NONE, then no code gets generated.
+**
+** This routine makes its own copy of zAff so that the caller is free
+** to modify zAff after this routine returns.
+*/
+static void codeApplyAffinity(Parse *pParse, int base, int n, char *zAff){
+  Vdbe *v = pParse->pVdbe;
+  if( zAff==0 ){
+    assert( pParse->db->mallocFailed );
+    return;
+  }
+  assert( v!=0 );
+
+  /* Adjust base and n to skip over SQLITE_AFF_BLOB and SQLITE_AFF_NONE
+  ** entries at the beginning and end of the affinity string.
+  */
+  assert( SQLITE_AFF_NONE<SQLITE_AFF_BLOB );
+  while( n>0 && zAff[0]<=SQLITE_AFF_BLOB ){
+    n--;
+    base++;
+    zAff++;
+  }
+  while( n>1 && zAff[n-1]<=SQLITE_AFF_BLOB ){
+    n--;
+  }
+
+  /* Code the OP_Affinity opcode if there is anything left to do. */
+  if( n>0 ){
+    sqlite3VdbeAddOp4(v, OP_Affinity, base, n, 0, zAff, n);
+  }
+}
+
+/*
+** Expression pRight, which is the RHS of a comparison operation, is
+** either a vector of n elements or, if n==1, a scalar expression.
+** Before the comparison operation, affinity zAff is to be applied
+** to the pRight values. This function modifies characters within the
+** affinity string to SQLITE_AFF_BLOB if either:
+**
+**   * the comparison will be performed with no affinity, or
+**   * the affinity change in zAff is guaranteed not to change the value.
+*/
+static void updateRangeAffinityStr(
+  Expr *pRight,                   /* RHS of comparison */
+  int n,                          /* Number of vector elements in comparison */
+  char *zAff                      /* Affinity string to modify */
+){
+  int i;
+  for(i=0; i<n; i++){
+    Expr *p = sqlite3VectorFieldSubexpr(pRight, i);
+    if( sqlite3CompareAffinity(p, zAff[i])==SQLITE_AFF_BLOB
+     || sqlite3ExprNeedsNoAffinityChange(p, zAff[i])
+    ){
+      zAff[i] = SQLITE_AFF_BLOB;
+    }
+  }
+}
+
+/*
+** The pOrderBy->a[].u.x.iOrderByCol values might be incorrect because
+** columns might have been rearranged in the result set.  This routine
+** fixes them up.
+**
+** pEList is the new result set.  The pEList->a[].u.x.iOrderByCol values
+** contain the *old* locations of each expression.  This is a temporary
+** use of u.x.iOrderByCol, not its intended use.  The caller must reset
+** u.x.iOrderByCol back to zero for all entries in pEList before the
+** caller returns.
+**
+** This routine changes pOrderBy->a[].u.x.iOrderByCol values from
+** pEList->a[N].u.x.iOrderByCol into N+1.  (The "+1" is because of the 1-based
+** indexing used by iOrderByCol.)  Or if no match, iOrderByCol is set to zero.
+*/
+static void adjustOrderByCol(ExprList *pOrderBy, ExprList *pEList){
+  int i, j;
+  if( pOrderBy==0 ) return;
+  for(i=0; i<pOrderBy->nExpr; i++){
+    int t = pOrderBy->a[i].u.x.iOrderByCol;
+    if( t==0 ) continue;
+    for(j=0; j<pEList->nExpr; j++){
+      if( pEList->a[j].u.x.iOrderByCol==t ){
+        pOrderBy->a[i].u.x.iOrderByCol = j+1;
+        break;
+      }
+    }
+    if( j>=pEList->nExpr ){
+      pOrderBy->a[i].u.x.iOrderByCol = 0;
+    }
+  }
+}
+
+
+/*
+** pX is an expression of the form:  (vector) IN (SELECT ...)
+** In other words, it is a vector IN operator with a SELECT clause on the
+** LHS.  But not all terms in the vector are indexable and the terms might
+** not be in the correct order for indexing.
+**
+** This routine makes a copy of the input pX expression and then adjusts
+** the vector on the LHS with corresponding changes to the SELECT so that
+** the vector contains only index terms and those terms are in the correct
+** order.  The modified IN expression is returned.  The caller is responsible
+** for deleting the returned expression.
+**
+** Example:
+**
+**    CREATE TABLE t1(a,b,c,d,e,f);
+**    CREATE INDEX t1x1 ON t1(e,c);
+**    SELECT * FROM t1 WHERE (a,b,c,d,e) IN (SELECT v,w,x,y,z FROM t2)
+**                           \_______________________________________/
+**                                     The pX expression
+**
+** Since only columns e and c can be used with the index, in that order,
+** the modified IN expression that is returned will be:
+**
+**        (e,c) IN (SELECT z,x FROM t2)
+**
+** The reduced pX is different from the original (obviously) and thus is
+** only used for indexing, to improve performance.  The original unaltered
+** IN expression must also be run on each output row for correctness.
+*/
+static Expr *removeUnindexableInClauseTerms(
+  Parse *pParse,        /* The parsing context */
+  int iEq,              /* Look at loop terms starting here */
+  WhereLoop *pLoop,     /* The current loop */
+  Expr *pX              /* The IN expression to be reduced */
+){
+  sqlite3 *db = pParse->db;
+  Select *pSelect;            /* Pointer to the SELECT on the RHS */
+  Expr *pNew;
+  pNew = sqlite3ExprDup(db, pX, 0);
+  if( db->mallocFailed==0 ){
+    for(pSelect=pNew->x.pSelect; pSelect; pSelect=pSelect->pPrior){
+      ExprList *pOrigRhs;         /* Original unmodified RHS */
+      ExprList *pOrigLhs = 0;     /* Original unmodified LHS */
+      ExprList *pRhs = 0;         /* New RHS after modifications */
+      ExprList *pLhs = 0;         /* New LHS after mods */
+      int i;                      /* Loop counter */
+
+      assert( ExprUseXSelect(pNew) );
+      pOrigRhs = pSelect->pEList;
+      assert( pNew->pLeft!=0 );
+      assert( ExprUseXList(pNew->pLeft) );
+      if( pSelect==pNew->x.pSelect ){
+        pOrigLhs = pNew->pLeft->x.pList;
+      }
+      for(i=iEq; i<pLoop->nLTerm; i++){
+        if( pLoop->aLTerm[i]->pExpr==pX ){
+          int iField;
+          assert( (pLoop->aLTerm[i]->eOperator & (WO_OR|WO_AND))==0 );
+          iField = pLoop->aLTerm[i]->u.x.iField - 1;
+          if( pOrigRhs->a[iField].pExpr==0 ) continue; /* Duplicate PK column */
+          pRhs = sqlite3ExprListAppend(pParse, pRhs, pOrigRhs->a[iField].pExpr);
+          pOrigRhs->a[iField].pExpr = 0;
+          if( pRhs ) pRhs->a[pRhs->nExpr-1].u.x.iOrderByCol = iField+1;
+          if( pOrigLhs ){
+            assert( pOrigLhs->a[iField].pExpr!=0 );
+            pLhs = sqlite3ExprListAppend(pParse,pLhs,pOrigLhs->a[iField].pExpr);
+            pOrigLhs->a[iField].pExpr = 0;
+          }
+        }
+      }
+      sqlite3ExprListDelete(db, pOrigRhs);
+      if( pOrigLhs ){
+        sqlite3ExprListDelete(db, pOrigLhs);
+        pNew->pLeft->x.pList = pLhs;
+      }
+      pSelect->pEList = pRhs;
+      pSelect->selId = ++pParse->nSelect; /* Req'd for SubrtnSig validity */
+      if( pLhs && pLhs->nExpr==1 ){
+        /* Take care here not to generate a TK_VECTOR containing only a
+        ** single value. Since the parser never creates such a vector, some
+        ** of the subroutines do not handle this case.  */
+        Expr *p = pLhs->a[0].pExpr;
+        pLhs->a[0].pExpr = 0;
+        sqlite3ExprDelete(db, pNew->pLeft);
+        pNew->pLeft = p;
+      }
+
+      /* If either the ORDER BY clause or the GROUP BY clause contains
+      ** references to result-set columns, those references might now be
+      ** obsolete.  So fix them up.
+      */
+      assert( pRhs!=0 || db->mallocFailed );
+      if( pRhs ){
+        adjustOrderByCol(pSelect->pOrderBy, pRhs);
+        adjustOrderByCol(pSelect->pGroupBy, pRhs);
+        for(i=0; i<pRhs->nExpr; i++) pRhs->a[i].u.x.iOrderByCol = 0;
+      }
+
+#if 0
+      printf("For indexing, change the IN expr:\n");
+      sqlite3TreeViewExpr(0, pX, 0);
+      printf("Into:\n");
+      sqlite3TreeViewExpr(0, pNew, 0);
+#endif
+    }
+  }
+  return pNew;
+}
+
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code for a single X IN (....) term of the WHERE clause.
+**
+** This is a special-case of codeEqualityTerm() that works for IN operators
+** only.  It is broken out into a subroutine because this case is
+** uncommon and by splitting it off into a subroutine, the common case
+** runs faster.
+**
+** The current value for the constraint is left in  register iTarget.
+** This routine sets up a loop that will iterate over all values of X.
+*/
+static SQLITE_NOINLINE void codeINTerm(
+  Parse *pParse,      /* The parsing context */
+  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
+  WhereLevel *pLevel, /* The level of the FROM clause we are working on */
+  int iEq,            /* Index of the equality term within this level */
+  int bRev,           /* True for reverse-order IN operations */
+  int iTarget         /* Attempt to leave results in this register */
+){
+  Expr *pX = pTerm->pExpr;
+  int eType = IN_INDEX_NOOP;
+  int iTab;
+  struct InLoop *pIn;
+  WhereLoop *pLoop = pLevel->pWLoop;
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  int nEq = 0;
+  int *aiMap = 0;
+
+  if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0
+    && pLoop->u.btree.pIndex!=0
+    && pLoop->u.btree.pIndex->aSortOrder[iEq]
+  ){
+    testcase( iEq==0 );
+    testcase( bRev );
+    bRev = !bRev;
+  }
+  assert( pX->op==TK_IN );
+
+  for(i=0; i<iEq; i++){
+    if( pLoop->aLTerm[i] && pLoop->aLTerm[i]->pExpr==pX ){
+      disableTerm(pLevel, pTerm);
+      return;
+    }
+  }
+  for(i=iEq;i<pLoop->nLTerm; i++){
+    assert( pLoop->aLTerm[i]!=0 );
+    if( pLoop->aLTerm[i]->pExpr==pX ) nEq++;
+  }
+
+  iTab = 0;
+  if( !ExprUseXSelect(pX) || pX->x.pSelect->pEList->nExpr==1 ){
+    eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, 0, &iTab);
+  }else{
+    Expr *pExpr = pTerm->pExpr;
+    if( pExpr->iTable==0 || !ExprHasProperty(pExpr, EP_Subrtn) ){
+      sqlite3 *db = pParse->db;
+      pX = removeUnindexableInClauseTerms(pParse, iEq, pLoop, pX);
+      if( !db->mallocFailed ){
+        aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*nEq);
+        eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap,&iTab);
+        pExpr->iTable = iTab;
+      }
+      sqlite3ExprDelete(db, pX);
+    }else{
+      int n = sqlite3ExprVectorSize(pX->pLeft);
+      aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*MAX(nEq,n));
+      eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap, &iTab);
+    }
+    pX = pExpr;
+  }
+
+  if( eType==IN_INDEX_INDEX_DESC ){
+    testcase( bRev );
+    bRev = !bRev;
+  }
+  sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iTab, 0);
+  VdbeCoverageIf(v, bRev);
+  VdbeCoverageIf(v, !bRev);
+
+  assert( (pLoop->wsFlags & WHERE_MULTI_OR)==0 );
+  pLoop->wsFlags |= WHERE_IN_ABLE;
+  if( pLevel->u.in.nIn==0 ){
+    pLevel->addrNxt = sqlite3VdbeMakeLabel(pParse);
+  }
+  if( iEq>0 && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0 ){
+    pLoop->wsFlags |= WHERE_IN_EARLYOUT;
+  }
+
+  i = pLevel->u.in.nIn;
+  pLevel->u.in.nIn += nEq;
+  pLevel->u.in.aInLoop =
+     sqlite3WhereRealloc(pTerm->pWC->pWInfo,
+                         pLevel->u.in.aInLoop,
+                         sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn);
+  pIn = pLevel->u.in.aInLoop;
+  if( pIn ){
+    int iMap = 0;               /* Index in aiMap[] */
+    pIn += i;
+    for(i=iEq;i<pLoop->nLTerm; i++){
+      if( pLoop->aLTerm[i]->pExpr==pX ){
+        int iOut = iTarget + i - iEq;
+        if( eType==IN_INDEX_ROWID ){
+          pIn->addrInTop = sqlite3VdbeAddOp2(v, OP_Rowid, iTab, iOut);
+        }else{
+          int iCol = aiMap ? aiMap[iMap++] : 0;
+          pIn->addrInTop = sqlite3VdbeAddOp3(v,OP_Column,iTab, iCol, iOut);
+        }
+        sqlite3VdbeAddOp1(v, OP_IsNull, iOut); VdbeCoverage(v);
+        if( i==iEq ){
+          pIn->iCur = iTab;
+          pIn->eEndLoopOp = bRev ? OP_Prev : OP_Next;
+          if( iEq>0 ){
+            pIn->iBase = iTarget - i;
+            pIn->nPrefix = i;
+          }else{
+            pIn->nPrefix = 0;
+          }
+        }else{
+          pIn->eEndLoopOp = OP_Noop;
+        }
+        pIn++;
+      }
+    }
+    testcase( iEq>0
+              && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0
+              && (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 );
+    if( iEq>0
+     && (pLoop->wsFlags & (WHERE_IN_SEEKSCAN|WHERE_VIRTUALTABLE))==0
+    ){
+      sqlite3VdbeAddOp3(v, OP_SeekHit, pLevel->iIdxCur, 0, iEq);
+    }
+  }else{
+    pLevel->u.in.nIn = 0;
+  }
+  sqlite3DbFree(pParse->db, aiMap);
+}
+#endif
+
+
+/*
+** Generate code for a single equality term of the WHERE clause.  An equality
+** term can be either X=expr or X IN (...).   pTerm is the term to be
+** coded.
+**
+** The current value for the constraint is left in a register, the index
+** of which is returned.  An attempt is made store the result in iTarget but
+** this is only guaranteed for TK_ISNULL and TK_IN constraints.  If the
+** constraint is a TK_EQ or TK_IS, then the current value might be left in
+** some other register and it is the caller's responsibility to compensate.
+**
+** For a constraint of the form X=expr, the expression is evaluated in
+** straight-line code.  For constraints of the form X IN (...)
+** this routine sets up a loop that will iterate over all values of X.
+*/
+static int codeEqualityTerm(
+  Parse *pParse,      /* The parsing context */
+  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
+  WhereLevel *pLevel, /* The level of the FROM clause we are working on */
+  int iEq,            /* Index of the equality term within this level */
+  int bRev,           /* True for reverse-order IN operations */
+  int iTarget         /* Attempt to leave results in this register */
+){
+  Expr *pX = pTerm->pExpr;
+  int iReg;                  /* Register holding results */
+
+  assert( pLevel->pWLoop->aLTerm[iEq]==pTerm );
+  assert( iTarget>0 );
+  if( pX->op==TK_EQ || pX->op==TK_IS ){
+    iReg = sqlite3ExprCodeTarget(pParse, pX->pRight, iTarget);
+  }else if( pX->op==TK_ISNULL ){
+    iReg = iTarget;
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_Null, 0, iReg);
+#ifndef SQLITE_OMIT_SUBQUERY
+  }else{
+    assert( pX->op==TK_IN );
+    iReg = iTarget;
+    codeINTerm(pParse, pTerm, pLevel, iEq, bRev, iTarget);
+#endif
+  }
+
+  /* As an optimization, try to disable the WHERE clause term that is
+  ** driving the index as it will always be true.  The correct answer is
+  ** obtained regardless, but we might get the answer with fewer CPU cycles
+  ** by omitting the term.
+  **
+  ** But do not disable the term unless we are certain that the term is
+  ** not a transitive constraint.  For an example of where that does not
+  ** work, see https://sqlite.org/forum/forumpost/eb8613976a (2021-05-04)
+  */
+  if( (pLevel->pWLoop->wsFlags & WHERE_TRANSCONS)==0
+   || (pTerm->eOperator & WO_EQUIV)==0
+  ){
+    disableTerm(pLevel, pTerm);
+  }
+
+  return iReg;
+}
+
+/*
+** Generate code that will evaluate all == and IN constraints for an
+** index scan.
+**
+** For example, consider table t1(a,b,c,d,e,f) with index i1(a,b,c).
+** Suppose the WHERE clause is this:  a==5 AND b IN (1,2,3) AND c>5 AND c<10
+** The index has as many as three equality constraints, but in this
+** example, the third "c" value is an inequality.  So only two
+** constraints are coded.  This routine will generate code to evaluate
+** a==5 and b IN (1,2,3).  The current values for a and b will be stored
+** in consecutive registers and the index of the first register is returned.
+**
+** In the example above nEq==2.  But this subroutine works for any value
+** of nEq including 0.  If nEq==0, this routine is nearly a no-op.
+** The only thing it does is allocate the pLevel->iMem memory cell and
+** compute the affinity string.
+**
+** The nExtraReg parameter is 0 or 1.  It is 0 if all WHERE clause constraints
+** are == or IN and are covered by the nEq.  nExtraReg is 1 if there is
+** an inequality constraint (such as the "c>=5 AND c<10" in the example) that
+** occurs after the nEq quality constraints.
+**
+** This routine allocates a range of nEq+nExtraReg memory cells and returns
+** the index of the first memory cell in that range. The code that
+** calls this routine will use that memory range to store keys for
+** start and termination conditions of the loop.
+** key value of the loop.  If one or more IN operators appear, then
+** this routine allocates an additional nEq memory cells for internal
+** use.
+**
+** Before returning, *pzAff is set to point to a buffer containing a
+** copy of the column affinity string of the index allocated using
+** sqlite3DbMalloc(). Except, entries in the copy of the string associated
+** with equality constraints that use BLOB or NONE affinity are set to
+** SQLITE_AFF_BLOB. This is to deal with SQL such as the following:
+**
+**   CREATE TABLE t1(a TEXT PRIMARY KEY, b);
+**   SELECT ... FROM t1 AS t2, t1 WHERE t1.a = t2.b;
+**
+** In the example above, the index on t1(a) has TEXT affinity. But since
+** the right hand side of the equality constraint (t2.b) has BLOB/NONE affinity,
+** no conversion should be attempted before using a t2.b value as part of
+** a key to search the index. Hence the first byte in the returned affinity
+** string in this example would be set to SQLITE_AFF_BLOB.
+*/
+static int codeAllEqualityTerms(
+  Parse *pParse,        /* Parsing context */
+  WhereLevel *pLevel,   /* Which nested loop of the FROM we are coding */
+  int bRev,             /* Reverse the order of IN operators */
+  int nExtraReg,        /* Number of extra registers to allocate */
+  char **pzAff          /* OUT: Set to point to affinity string */
+){
+  u16 nEq;                      /* The number of == or IN constraints to code */
+  u16 nSkip;                    /* Number of left-most columns to skip */
+  Vdbe *v = pParse->pVdbe;      /* The vm under construction */
+  Index *pIdx;                  /* The index being used for this loop */
+  WhereTerm *pTerm;             /* A single constraint term */
+  WhereLoop *pLoop;             /* The WhereLoop object */
+  int j;                        /* Loop counter */
+  int regBase;                  /* Base register */
+  int nReg;                     /* Number of registers to allocate */
+  char *zAff;                   /* Affinity string to return */
+
+  /* This module is only called on query plans that use an index. */
+  pLoop = pLevel->pWLoop;
+  assert( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 );
+  nEq = pLoop->u.btree.nEq;
+  nSkip = pLoop->nSkip;
+  pIdx = pLoop->u.btree.pIndex;
+  assert( pIdx!=0 );
+
+  /* Figure out how many memory cells we will need then allocate them.
+  */
+  regBase = pParse->nMem + 1;
+  nReg = nEq + nExtraReg;
+  pParse->nMem += nReg;
+
+  zAff = sqlite3DbStrDup(pParse->db,sqlite3IndexAffinityStr(pParse->db,pIdx));
+  assert( zAff!=0 || pParse->db->mallocFailed );
+
+  if( nSkip ){
+    int iIdxCur = pLevel->iIdxCur;
+    sqlite3VdbeAddOp3(v, OP_Null, 0, regBase, regBase+nSkip-1);
+    sqlite3VdbeAddOp1(v, (bRev?OP_Last:OP_Rewind), iIdxCur);
+    VdbeCoverageIf(v, bRev==0);
+    VdbeCoverageIf(v, bRev!=0);
+    VdbeComment((v, "begin skip-scan on %s", pIdx->zName));
+    j = sqlite3VdbeAddOp0(v, OP_Goto);
+    assert( pLevel->addrSkip==0 );
+    pLevel->addrSkip = sqlite3VdbeAddOp4Int(v, (bRev?OP_SeekLT:OP_SeekGT),
+                            iIdxCur, 0, regBase, nSkip);
+    VdbeCoverageIf(v, bRev==0);
+    VdbeCoverageIf(v, bRev!=0);
+    sqlite3VdbeJumpHere(v, j);
+    for(j=0; j<nSkip; j++){
+      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, j, regBase+j);
+      testcase( pIdx->aiColumn[j]==XN_EXPR );
+      VdbeComment((v, "%s", explainIndexColumnName(pIdx, j)));
+    }
+  }
+
+  /* Evaluate the equality constraints
+  */
+  assert( zAff==0 || (int)strlen(zAff)>=nEq );
+  for(j=nSkip; j<nEq; j++){
+    int r1;
+    pTerm = pLoop->aLTerm[j];
+    assert( pTerm!=0 );
+    /* The following testcase is true for indices with redundant columns.
+    ** Ex: CREATE INDEX i1 ON t1(a,b,a); SELECT * FROM t1 WHERE a=0 AND b=0; */
+    testcase( (pTerm->wtFlags & TERM_CODED)!=0 );
+    testcase( pTerm->wtFlags & TERM_VIRTUAL );
+    r1 = codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, regBase+j);
+    if( r1!=regBase+j ){
+      if( nReg==1 ){
+        sqlite3ReleaseTempReg(pParse, regBase);
+        regBase = r1;
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Copy, r1, regBase+j);
+      }
+    }
+    if( pTerm->eOperator & WO_IN ){
+      if( pTerm->pExpr->flags & EP_xIsSelect ){
+        /* No affinity ever needs to be (or should be) applied to a value
+        ** from the RHS of an "? IN (SELECT ...)" expression. The
+        ** sqlite3FindInIndex() routine has already ensured that the
+        ** affinity of the comparison has been applied to the value.  */
+        if( zAff ) zAff[j] = SQLITE_AFF_BLOB;
+      }
+    }else if( (pTerm->eOperator & WO_ISNULL)==0 ){
+      Expr *pRight = pTerm->pExpr->pRight;
+      if( (pTerm->wtFlags & TERM_IS)==0 && sqlite3ExprCanBeNull(pRight) ){
+        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+j, pLevel->addrBrk);
+        VdbeCoverage(v);
+      }
+      if( pParse->nErr==0 ){
+        assert( pParse->db->mallocFailed==0 );
+        if( sqlite3CompareAffinity(pRight, zAff[j])==SQLITE_AFF_BLOB ){
+          zAff[j] = SQLITE_AFF_BLOB;
+        }
+        if( sqlite3ExprNeedsNoAffinityChange(pRight, zAff[j]) ){
+          zAff[j] = SQLITE_AFF_BLOB;
+        }
+      }
+    }
+  }
+  *pzAff = zAff;
+  return regBase;
+}
+
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+/*
+** If the most recently coded instruction is a constant range constraint
+** (a string literal) that originated from the LIKE optimization, then
+** set P3 and P5 on the OP_String opcode so that the string will be cast
+** to a BLOB at appropriate times.
+**
+** The LIKE optimization trys to evaluate "x LIKE 'abc%'" as a range
+** expression: "x>='ABC' AND x<'abd'".  But this requires that the range
+** scan loop run twice, once for strings and a second time for BLOBs.
+** The OP_String opcodes on the second pass convert the upper and lower
+** bound string constants to blobs.  This routine makes the necessary changes
+** to the OP_String opcodes for that to happen.
+**
+** Except, of course, if SQLITE_LIKE_DOESNT_MATCH_BLOBS is defined, then
+** only the one pass through the string space is required, so this routine
+** becomes a no-op.
+*/
+static void whereLikeOptimizationStringFixup(
+  Vdbe *v,                /* prepared statement under construction */
+  WhereLevel *pLevel,     /* The loop that contains the LIKE operator */
+  WhereTerm *pTerm        /* The upper or lower bound just coded */
+){
+  if( pTerm->wtFlags & TERM_LIKEOPT ){
+    VdbeOp *pOp;
+    assert( pLevel->iLikeRepCntr>0 );
+    pOp = sqlite3VdbeGetLastOp(v);
+    assert( pOp!=0 );
+    assert( pOp->opcode==OP_String8
+            || pTerm->pWC->pWInfo->pParse->db->mallocFailed );
+    pOp->p3 = (int)(pLevel->iLikeRepCntr>>1);  /* Register holding counter */
+    pOp->p5 = (u8)(pLevel->iLikeRepCntr&1);    /* ASC or DESC */
+  }
+}
+#else
+# define whereLikeOptimizationStringFixup(A,B,C)
+#endif
+
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/*
+** Information is passed from codeCursorHint() down to individual nodes of
+** the expression tree (by sqlite3WalkExpr()) using an instance of this
+** structure.
+*/
+struct CCurHint {
+  int iTabCur;    /* Cursor for the main table */
+  int iIdxCur;    /* Cursor for the index, if pIdx!=0.  Unused otherwise */
+  Index *pIdx;    /* The index used to access the table */
+};
+
+/*
+** This function is called for every node of an expression that is a candidate
+** for a cursor hint on an index cursor.  For TK_COLUMN nodes that reference
+** the table CCurHint.iTabCur, verify that the same column can be
+** accessed through the index.  If it cannot, then set pWalker->eCode to 1.
+*/
+static int codeCursorHintCheckExpr(Walker *pWalker, Expr *pExpr){
+  struct CCurHint *pHint = pWalker->u.pCCurHint;
+  assert( pHint->pIdx!=0 );
+  if( pExpr->op==TK_COLUMN
+   && pExpr->iTable==pHint->iTabCur
+   && sqlite3TableColumnToIndex(pHint->pIdx, pExpr->iColumn)<0
+  ){
+    pWalker->eCode = 1;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Test whether or not expression pExpr, which was part of a WHERE clause,
+** should be included in the cursor-hint for a table that is on the rhs
+** of a LEFT JOIN. Set Walker.eCode to non-zero before returning if the
+** expression is not suitable.
+**
+** An expression is unsuitable if it might evaluate to non NULL even if
+** a TK_COLUMN node that does affect the value of the expression is set
+** to NULL. For example:
+**
+**   col IS NULL
+**   col IS NOT NULL
+**   coalesce(col, 1)
+**   CASE WHEN col THEN 0 ELSE 1 END
+*/
+static int codeCursorHintIsOrFunction(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_IS
+   || pExpr->op==TK_ISNULL || pExpr->op==TK_ISNOT
+   || pExpr->op==TK_NOTNULL || pExpr->op==TK_CASE
+  ){
+    pWalker->eCode = 1;
+  }else if( pExpr->op==TK_FUNCTION ){
+    int d1;
+    char d2[4];
+    if( 0==sqlite3IsLikeFunction(pWalker->pParse->db, pExpr, &d1, d2) ){
+      pWalker->eCode = 1;
+    }
+  }
+
+  return WRC_Continue;
+}
+
+
+/*
+** This function is called on every node of an expression tree used as an
+** argument to the OP_CursorHint instruction. If the node is a TK_COLUMN
+** that accesses any table other than the one identified by
+** CCurHint.iTabCur, then do the following:
+**
+**   1) allocate a register and code an OP_Column instruction to read
+**      the specified column into the new register, and
+**
+**   2) transform the expression node to a TK_REGISTER node that reads
+**      from the newly populated register.
+**
+** Also, if the node is a TK_COLUMN that does access the table identified
+** by pCCurHint.iTabCur, and an index is being used (which we will
+** know because CCurHint.pIdx!=0) then transform the TK_COLUMN into
+** an access of the index rather than the original table.
+*/
+static int codeCursorHintFixExpr(Walker *pWalker, Expr *pExpr){
+  int rc = WRC_Continue;
+  int reg;
+  struct CCurHint *pHint = pWalker->u.pCCurHint;
+  if( pExpr->op==TK_COLUMN ){
+    if( pExpr->iTable!=pHint->iTabCur ){
+      reg = ++pWalker->pParse->nMem;   /* Register for column value */
+      reg = sqlite3ExprCodeTarget(pWalker->pParse, pExpr, reg);
+      pExpr->op = TK_REGISTER;
+      pExpr->iTable = reg;
+    }else if( pHint->pIdx!=0 ){
+      pExpr->iTable = pHint->iIdxCur;
+      pExpr->iColumn = sqlite3TableColumnToIndex(pHint->pIdx, pExpr->iColumn);
+      assert( pExpr->iColumn>=0 );
+    }
+  }else if( pExpr->pAggInfo ){
+    rc = WRC_Prune;
+    reg = ++pWalker->pParse->nMem;   /* Register for column value */
+    reg = sqlite3ExprCodeTarget(pWalker->pParse, pExpr, reg);
+    pExpr->op = TK_REGISTER;
+    pExpr->iTable = reg;
+  }else if( pExpr->op==TK_TRUEFALSE ){
+    /* Do not walk disabled expressions.  tag-20230504-1 */
+    return WRC_Prune;
+  }
+  return rc;
+}
+
+/*
+** Insert an OP_CursorHint instruction if it is appropriate to do so.
+*/
+static void codeCursorHint(
+  SrcItem *pTabItem,  /* FROM clause item */
+  WhereInfo *pWInfo,    /* The where clause */
+  WhereLevel *pLevel,   /* Which loop to provide hints for */
+  WhereTerm *pEndRange  /* Hint this end-of-scan boundary term if not NULL */
+){
+  Parse *pParse = pWInfo->pParse;
+  sqlite3 *db = pParse->db;
+  Vdbe *v = pParse->pVdbe;
+  Expr *pExpr = 0;
+  WhereLoop *pLoop = pLevel->pWLoop;
+  int iCur;
+  WhereClause *pWC;
+  WhereTerm *pTerm;
+  int i, j;
+  struct CCurHint sHint;
+  Walker sWalker;
+
+  if( OptimizationDisabled(db, SQLITE_CursorHints) ) return;
+  iCur = pLevel->iTabCur;
+  assert( iCur==pWInfo->pTabList->a[pLevel->iFrom].iCursor );
+  sHint.iTabCur = iCur;
+  sHint.iIdxCur = pLevel->iIdxCur;
+  sHint.pIdx = pLoop->u.btree.pIndex;
+  memset(&sWalker, 0, sizeof(sWalker));
+  sWalker.pParse = pParse;
+  sWalker.u.pCCurHint = &sHint;
+  pWC = &pWInfo->sWC;
+  for(i=0; i<pWC->nBase; i++){
+    pTerm = &pWC->a[i];
+    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+    if( pTerm->prereqAll & pLevel->notReady ) continue;
+
+    /* Any terms specified as part of the ON(...) clause for any LEFT
+    ** JOIN for which the current table is not the rhs are omitted
+    ** from the cursor-hint.
+    **
+    ** If this table is the rhs of a LEFT JOIN, "IS" or "IS NULL" terms
+    ** that were specified as part of the WHERE clause must be excluded.
+    ** This is to address the following:
+    **
+    **   SELECT ... t1 LEFT JOIN t2 ON (t1.a=t2.b) WHERE t2.c IS NULL;
+    **
+    ** Say there is a single row in t2 that matches (t1.a=t2.b), but its
+    ** t2.c values is not NULL. If the (t2.c IS NULL) constraint is
+    ** pushed down to the cursor, this row is filtered out, causing
+    ** SQLite to synthesize a row of NULL values. Which does match the
+    ** WHERE clause, and so the query returns a row. Which is incorrect.
+    **
+    ** For the same reason, WHERE terms such as:
+    **
+    **   WHERE 1 = (t2.c IS NULL)
+    **
+    ** are also excluded. See codeCursorHintIsOrFunction() for details.
+    */
+    if( pTabItem->fg.jointype & JT_LEFT ){
+      Expr *pExpr = pTerm->pExpr;
+      if( !ExprHasProperty(pExpr, EP_OuterON)
+       || pExpr->w.iJoin!=pTabItem->iCursor
+      ){
+        sWalker.eCode = 0;
+        sWalker.xExprCallback = codeCursorHintIsOrFunction;
+        sqlite3WalkExpr(&sWalker, pTerm->pExpr);
+        if( sWalker.eCode ) continue;
+      }
+    }else{
+      if( ExprHasProperty(pTerm->pExpr, EP_OuterON) ) continue;
+    }
+
+    /* All terms in pWLoop->aLTerm[] except pEndRange are used to initialize
+    ** the cursor.  These terms are not needed as hints for a pure range
+    ** scan (that has no == terms) so omit them. */
+    if( pLoop->u.btree.nEq==0 && pTerm!=pEndRange ){
+      for(j=0; j<pLoop->nLTerm && pLoop->aLTerm[j]!=pTerm; j++){}
+      if( j<pLoop->nLTerm ) continue;
+    }
+
+    /* No subqueries or non-deterministic functions allowed */
+    if( sqlite3ExprContainsSubquery(pTerm->pExpr) ) continue;
+
+    /* For an index scan, make sure referenced columns are actually in
+    ** the index. */
+    if( sHint.pIdx!=0 ){
+      sWalker.eCode = 0;
+      sWalker.xExprCallback = codeCursorHintCheckExpr;
+      sqlite3WalkExpr(&sWalker, pTerm->pExpr);
+      if( sWalker.eCode ) continue;
+    }
+
+    /* If we survive all prior tests, that means this term is worth hinting */
+    pExpr = sqlite3ExprAnd(pParse, pExpr, sqlite3ExprDup(db, pTerm->pExpr, 0));
+  }
+  if( pExpr!=0 ){
+    sWalker.xExprCallback = codeCursorHintFixExpr;
+    if( pParse->nErr==0 ) sqlite3WalkExpr(&sWalker, pExpr);
+    sqlite3VdbeAddOp4(v, OP_CursorHint,
+                      (sHint.pIdx ? sHint.iIdxCur : sHint.iTabCur), 0, 0,
+                      (const char*)pExpr, P4_EXPR);
+  }
+}
+#else
+# define codeCursorHint(A,B,C,D)  /* No-op */
+#endif /* SQLITE_ENABLE_CURSOR_HINTS */
+
+/*
+** Cursor iCur is open on an intkey b-tree (a table). Register iRowid contains
+** a rowid value just read from cursor iIdxCur, open on index pIdx. This
+** function generates code to do a deferred seek of cursor iCur to the
+** rowid stored in register iRowid.
+**
+** Normally, this is just:
+**
+**   OP_DeferredSeek $iCur $iRowid
+**
+** Which causes a seek on $iCur to the row with rowid $iRowid.
+**
+** However, if the scan currently being coded is a branch of an OR-loop and
+** the statement currently being coded is a SELECT, then additional information
+** is added that might allow OP_Column to omit the seek and instead do its
+** lookup on the index, thus avoiding an expensive seek operation.  To
+** enable this optimization, the P3 of OP_DeferredSeek is set to iIdxCur
+** and P4 is set to an array of integers containing one entry for each column
+** in the table.  For each table column, if the column is the i'th
+** column of the index, then the corresponding array entry is set to (i+1).
+** If the column does not appear in the index at all, the array entry is set
+** to 0.  The OP_Column opcode can check this array to see if the column it
+** wants is in the index and if it is, it will substitute the index cursor
+** and column number and continue with those new values, rather than seeking
+** the table cursor.
+*/
+static void codeDeferredSeek(
+  WhereInfo *pWInfo,              /* Where clause context */
+  Index *pIdx,                    /* Index scan is using */
+  int iCur,                       /* Cursor for IPK b-tree */
+  int iIdxCur                     /* Index cursor */
+){
+  Parse *pParse = pWInfo->pParse; /* Parse context */
+  Vdbe *v = pParse->pVdbe;        /* Vdbe to generate code within */
+
+  assert( iIdxCur>0 );
+  assert( pIdx->aiColumn[pIdx->nColumn-1]==-1 );
+
+  pWInfo->bDeferredSeek = 1;
+  sqlite3VdbeAddOp3(v, OP_DeferredSeek, iIdxCur, 0, iCur);
+  if( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))
+   && DbMaskAllZero(sqlite3ParseToplevel(pParse)->writeMask)
+  ){
+    int i;
+    Table *pTab = pIdx->pTable;
+    u32 *ai = (u32*)sqlite3DbMallocZero(pParse->db, sizeof(u32)*(pTab->nCol+1));
+    if( ai ){
+      ai[0] = pTab->nCol;
+      for(i=0; i<pIdx->nColumn-1; i++){
+        int x1, x2;
+        assert( pIdx->aiColumn[i]<pTab->nCol );
+        x1 = pIdx->aiColumn[i];
+        x2 = sqlite3TableColumnToStorage(pTab, x1);
+        testcase( x1!=x2 );
+        if( x1>=0 ) ai[x2+1] = i+1;
+      }
+      sqlite3VdbeChangeP4(v, -1, (char*)ai, P4_INTARRAY);
+    }
+  }
+}
+
+/*
+** If the expression passed as the second argument is a vector, generate
+** code to write the first nReg elements of the vector into an array
+** of registers starting with iReg.
+**
+** If the expression is not a vector, then nReg must be passed 1. In
+** this case, generate code to evaluate the expression and leave the
+** result in register iReg.
+*/
+static void codeExprOrVector(Parse *pParse, Expr *p, int iReg, int nReg){
+  assert( nReg>0 );
+  if( p && sqlite3ExprIsVector(p) ){
+#ifndef SQLITE_OMIT_SUBQUERY
+    if( ExprUseXSelect(p) ){
+      Vdbe *v = pParse->pVdbe;
+      int iSelect;
+      assert( p->op==TK_SELECT );
+      iSelect = sqlite3CodeSubselect(pParse, p);
+      sqlite3VdbeAddOp3(v, OP_Copy, iSelect, iReg, nReg-1);
+    }else
+#endif
+    {
+      int i;
+      const ExprList *pList;
+      assert( ExprUseXList(p) );
+      pList = p->x.pList;
+      assert( nReg<=pList->nExpr );
+      for(i=0; i<nReg; i++){
+        sqlite3ExprCode(pParse, pList->a[i].pExpr, iReg+i);
+      }
+    }
+  }else{
+    assert( nReg==1 || pParse->nErr );
+    sqlite3ExprCode(pParse, p, iReg);
+  }
+}
+
+/*
+** The pTruth expression is always true because it is the WHERE clause
+** a partial index that is driving a query loop.  Look through all of the
+** WHERE clause terms on the query, and if any of those terms must be
+** true because pTruth is true, then mark those WHERE clause terms as
+** coded.
+*/
+static void whereApplyPartialIndexConstraints(
+  Expr *pTruth,
+  int iTabCur,
+  WhereClause *pWC
+){
+  int i;
+  WhereTerm *pTerm;
+  while( pTruth->op==TK_AND ){
+    whereApplyPartialIndexConstraints(pTruth->pLeft, iTabCur, pWC);
+    pTruth = pTruth->pRight;
+  }
+  for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+    Expr *pExpr;
+    if( pTerm->wtFlags & TERM_CODED ) continue;
+    pExpr = pTerm->pExpr;
+    if( sqlite3ExprCompare(0, pExpr, pTruth, iTabCur)==0 ){
+      pTerm->wtFlags |= TERM_CODED;
+    }
+  }
+}
+
+/*
+** This routine is called right after An OP_Filter has been generated and
+** before the corresponding index search has been performed.  This routine
+** checks to see if there are additional Bloom filters in inner loops that
+** can be checked prior to doing the index lookup.  If there are available
+** inner-loop Bloom filters, then evaluate those filters now, before the
+** index lookup.  The idea is that a Bloom filter check is way faster than
+** an index lookup, and the Bloom filter might return false, meaning that
+** the index lookup can be skipped.
+**
+** We know that an inner loop uses a Bloom filter because it has the
+** WhereLevel.regFilter set.  If an inner-loop Bloom filter is checked,
+** then clear the WhereLevel.regFilter value to prevent the Bloom filter
+** from being checked a second time when the inner loop is evaluated.
+*/
+static SQLITE_NOINLINE void filterPullDown(
+  Parse *pParse,       /* Parsing context */
+  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
+  int iLevel,          /* Which level of pWInfo->a[] should be coded */
+  int addrNxt,         /* Jump here to bypass inner loops */
+  Bitmask notReady     /* Loops that are not ready */
+){
+  while( ++iLevel < pWInfo->nLevel ){
+    WhereLevel *pLevel = &pWInfo->a[iLevel];
+    WhereLoop *pLoop = pLevel->pWLoop;
+    if( pLevel->regFilter==0 ) continue;
+    if( pLevel->pWLoop->nSkip ) continue;
+    /*         ,--- Because sqlite3ConstructBloomFilter() has will not have set
+    **  vvvvv--'    pLevel->regFilter if this were true. */
+    if( NEVER(pLoop->prereq & notReady) ) continue;
+    assert( pLevel->addrBrk==0 );
+    pLevel->addrBrk = addrNxt;
+    if( pLoop->wsFlags & WHERE_IPK ){
+      WhereTerm *pTerm = pLoop->aLTerm[0];
+      int regRowid;
+      assert( pTerm!=0 );
+      assert( pTerm->pExpr!=0 );
+      testcase( pTerm->wtFlags & TERM_VIRTUAL );
+      regRowid = sqlite3GetTempReg(pParse);
+      regRowid = codeEqualityTerm(pParse, pTerm, pLevel, 0, 0, regRowid);
+      sqlite3VdbeAddOp2(pParse->pVdbe, OP_MustBeInt, regRowid, addrNxt);
+      VdbeCoverage(pParse->pVdbe);
+      sqlite3VdbeAddOp4Int(pParse->pVdbe, OP_Filter, pLevel->regFilter,
+                           addrNxt, regRowid, 1);
+      VdbeCoverage(pParse->pVdbe);
+    }else{
+      u16 nEq = pLoop->u.btree.nEq;
+      int r1;
+      char *zStartAff;
+
+      assert( pLoop->wsFlags & WHERE_INDEXED );
+      assert( (pLoop->wsFlags & WHERE_COLUMN_IN)==0 );
+      r1 = codeAllEqualityTerms(pParse,pLevel,0,0,&zStartAff);
+      codeApplyAffinity(pParse, r1, nEq, zStartAff);
+      sqlite3DbFree(pParse->db, zStartAff);
+      sqlite3VdbeAddOp4Int(pParse->pVdbe, OP_Filter, pLevel->regFilter,
+                           addrNxt, r1, nEq);
+      VdbeCoverage(pParse->pVdbe);
+    }
+    pLevel->regFilter = 0;
+    pLevel->addrBrk = 0;
+  }
+}
+
+/*
+** Loop pLoop is a WHERE_INDEXED level that uses at least one IN(...)
+** operator. Return true if level pLoop is guaranteed to visit only one
+** row for each key generated for the index.
+*/
+static int whereLoopIsOneRow(WhereLoop *pLoop){
+  if( pLoop->u.btree.pIndex->onError
+   && pLoop->nSkip==0
+   && pLoop->u.btree.nEq==pLoop->u.btree.pIndex->nKeyCol
+  ){
+    int ii;
+    for(ii=0; ii<pLoop->u.btree.nEq; ii++){
+      if( pLoop->aLTerm[ii]->eOperator & (WO_IS|WO_ISNULL) ){
+        return 0;
+      }
+    }
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Generate code for the start of the iLevel-th loop in the WHERE clause
+** implementation described by pWInfo.
+*/
+SQLITE_PRIVATE Bitmask sqlite3WhereCodeOneLoopStart(
+  Parse *pParse,       /* Parsing context */
+  Vdbe *v,             /* Prepared statement under construction */
+  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
+  int iLevel,          /* Which level of pWInfo->a[] should be coded */
+  WhereLevel *pLevel,  /* The current level pointer */
+  Bitmask notReady     /* Which tables are currently available */
+){
+  int j, k;            /* Loop counters */
+  int iCur;            /* The VDBE cursor for the table */
+  int addrNxt;         /* Where to jump to continue with the next IN case */
+  int bRev;            /* True if we need to scan in reverse order */
+  WhereLoop *pLoop;    /* The WhereLoop object being coded */
+  WhereClause *pWC;    /* Decomposition of the entire WHERE clause */
+  WhereTerm *pTerm;               /* A WHERE clause term */
+  sqlite3 *db;                    /* Database connection */
+  SrcItem *pTabItem;              /* FROM clause term being coded */
+  int addrBrk;                    /* Jump here to break out of the loop */
+  int addrHalt;                   /* addrBrk for the outermost loop */
+  int addrCont;                   /* Jump here to continue with next cycle */
+  int iRowidReg = 0;        /* Rowid is stored in this register, if not zero */
+  int iReleaseReg = 0;      /* Temp register to free before returning */
+  Index *pIdx = 0;          /* Index used by loop (if any) */
+  int iLoop;                /* Iteration of constraint generator loop */
+
+  pWC = &pWInfo->sWC;
+  db = pParse->db;
+  pLoop = pLevel->pWLoop;
+  pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
+  iCur = pTabItem->iCursor;
+  pLevel->notReady = notReady & ~sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur);
+  bRev = (pWInfo->revMask>>iLevel)&1;
+  VdbeModuleComment((v, "Begin WHERE-loop%d: %s",
+                     iLevel, pTabItem->pSTab->zName));
+#if WHERETRACE_ENABLED /* 0x4001 */
+  if( sqlite3WhereTrace & 0x1 ){
+    sqlite3DebugPrintf("Coding level %d of %d:  notReady=%llx  iFrom=%d\n",
+       iLevel, pWInfo->nLevel, (u64)notReady, pLevel->iFrom);
+    if( sqlite3WhereTrace & 0x1000 ){
+      sqlite3WhereLoopPrint(pLoop, pWC);
+    }
+  }
+  if( (sqlite3WhereTrace & 0x4001)==0x4001 ){
+    if( iLevel==0 ){
+      sqlite3DebugPrintf("WHERE clause being coded:\n");
+      sqlite3TreeViewExpr(0, pWInfo->pWhere, 0);
+    }
+    sqlite3DebugPrintf("All WHERE-clause terms before coding:\n");
+    sqlite3WhereClausePrint(pWC);
+  }
+#endif
+
+  /* Create labels for the "break" and "continue" instructions
+  ** for the current loop.  Jump to addrBrk to break out of a loop.
+  ** Jump to cont to go immediately to the next iteration of the
+  ** loop.
+  **
+  ** When there is an IN operator, we also have a "addrNxt" label that
+  ** means to continue with the next IN value combination.  When
+  ** there are no IN operators in the constraints, the "addrNxt" label
+  ** is the same as "addrBrk".
+  */
+  addrBrk = pLevel->addrBrk = pLevel->addrNxt = sqlite3VdbeMakeLabel(pParse);
+  addrCont = pLevel->addrCont = sqlite3VdbeMakeLabel(pParse);
+
+  /* If this is the right table of a LEFT OUTER JOIN, allocate and
+  ** initialize a memory cell that records if this table matches any
+  ** row of the left table of the join.
+  */
+  assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))
+       || pLevel->iFrom>0 || (pTabItem[0].fg.jointype & JT_LEFT)==0
+  );
+  if( pLevel->iFrom>0 && (pTabItem[0].fg.jointype & JT_LEFT)!=0 ){
+    pLevel->iLeftJoin = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
+    VdbeComment((v, "init LEFT JOIN match flag"));
+  }
+
+  /* Compute a safe address to jump to if we discover that the table for
+  ** this loop is empty and can never contribute content. */
+  for(j=iLevel; j>0; j--){
+    if( pWInfo->a[j].iLeftJoin ) break;
+    if( pWInfo->a[j].pRJ ) break;
+  }
+  addrHalt = pWInfo->a[j].addrBrk;
+
+  /* Special case of a FROM clause subquery implemented as a co-routine */
+  if( pTabItem->fg.viaCoroutine ){
+    int regYield;
+    Subquery *pSubq;
+    assert( pTabItem->fg.isSubquery && pTabItem->u4.pSubq!=0 );
+    pSubq = pTabItem->u4.pSubq;
+    regYield = pSubq->regReturn;
+    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pSubq->addrFillSub);
+    pLevel->p2 =  sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk);
+    VdbeCoverage(v);
+    VdbeComment((v, "next row of %s", pTabItem->pSTab->zName));
+    pLevel->op = OP_Goto;
+  }else
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if(  (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
+    /* Case 1:  The table is a virtual-table.  Use the VFilter and VNext
+    **          to access the data.
+    */
+    int iReg;   /* P3 Value for OP_VFilter */
+    int addrNotFound;
+    int nConstraint = pLoop->nLTerm;
+
+    iReg = sqlite3GetTempRange(pParse, nConstraint+2);
+    addrNotFound = pLevel->addrBrk;
+    for(j=0; j<nConstraint; j++){
+      int iTarget = iReg+j+2;
+      pTerm = pLoop->aLTerm[j];
+      if( NEVER(pTerm==0) ) continue;
+      if( pTerm->eOperator & WO_IN ){
+        if( SMASKBIT32(j) & pLoop->u.vtab.mHandleIn ){
+          int iTab = pParse->nTab++;
+          int iCache = ++pParse->nMem;
+          sqlite3CodeRhsOfIN(pParse, pTerm->pExpr, iTab);
+          sqlite3VdbeAddOp3(v, OP_VInitIn, iTab, iTarget, iCache);
+        }else{
+          codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, iTarget);
+          addrNotFound = pLevel->addrNxt;
+        }
+      }else{
+        Expr *pRight = pTerm->pExpr->pRight;
+        codeExprOrVector(pParse, pRight, iTarget, 1);
+        if( pTerm->eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET
+         && pLoop->u.vtab.bOmitOffset
+        ){
+          assert( pTerm->eOperator==WO_AUX );
+          assert( pWInfo->pSelect!=0 );
+          assert( pWInfo->pSelect->iOffset>0 );
+          sqlite3VdbeAddOp2(v, OP_Integer, 0, pWInfo->pSelect->iOffset);
+          VdbeComment((v,"Zero OFFSET counter"));
+        }
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_Integer, pLoop->u.vtab.idxNum, iReg);
+    sqlite3VdbeAddOp2(v, OP_Integer, nConstraint, iReg+1);
+    sqlite3VdbeAddOp4(v, OP_VFilter, iCur, addrNotFound, iReg,
+                      pLoop->u.vtab.idxStr,
+                      pLoop->u.vtab.needFree ? P4_DYNAMIC : P4_STATIC);
+    VdbeCoverage(v);
+    pLoop->u.vtab.needFree = 0;
+    /* An OOM inside of AddOp4(OP_VFilter) instruction above might have freed
+    ** the u.vtab.idxStr.  NULL it out to prevent a use-after-free */
+    if( db->mallocFailed ) pLoop->u.vtab.idxStr = 0;
+    pLevel->p1 = iCur;
+    pLevel->op = pWInfo->eOnePass ? OP_Noop : OP_VNext;
+    pLevel->p2 = sqlite3VdbeCurrentAddr(v);
+    assert( (pLoop->wsFlags & WHERE_MULTI_OR)==0 );
+
+    for(j=0; j<nConstraint; j++){
+      pTerm = pLoop->aLTerm[j];
+      if( j<16 && (pLoop->u.vtab.omitMask>>j)&1 ){
+        disableTerm(pLevel, pTerm);
+        continue;
+      }
+      if( (pTerm->eOperator & WO_IN)!=0
+       && (SMASKBIT32(j) & pLoop->u.vtab.mHandleIn)==0
+       && !db->mallocFailed
+      ){
+        Expr *pCompare;  /* The comparison operator */
+        Expr *pRight;    /* RHS of the comparison */
+        VdbeOp *pOp;     /* Opcode to access the value of the IN constraint */
+        int iIn;         /* IN loop corresponding to the j-th constraint */
+
+        /* Reload the constraint value into reg[iReg+j+2].  The same value
+        ** was loaded into the same register prior to the OP_VFilter, but
+        ** the xFilter implementation might have changed the datatype or
+        ** encoding of the value in the register, so it *must* be reloaded.
+        */
+        for(iIn=0; ALWAYS(iIn<pLevel->u.in.nIn); iIn++){
+          pOp = sqlite3VdbeGetOp(v, pLevel->u.in.aInLoop[iIn].addrInTop);
+          if( (pOp->opcode==OP_Column && pOp->p3==iReg+j+2)
+           || (pOp->opcode==OP_Rowid && pOp->p2==iReg+j+2)
+          ){
+            testcase( pOp->opcode==OP_Rowid );
+            sqlite3VdbeAddOp3(v, pOp->opcode, pOp->p1, pOp->p2, pOp->p3);
+            break;
+          }
+        }
+
+        /* Generate code that will continue to the next row if
+        ** the IN constraint is not satisfied
+        */
+        pCompare = sqlite3PExpr(pParse, TK_EQ, 0, 0);
+        if( !db->mallocFailed ){
+          int iFld = pTerm->u.x.iField;
+          Expr *pLeft = pTerm->pExpr->pLeft;
+          assert( pLeft!=0 );
+          if( iFld>0 ){
+            assert( pLeft->op==TK_VECTOR );
+            assert( ExprUseXList(pLeft) );
+            assert( iFld<=pLeft->x.pList->nExpr );
+            pCompare->pLeft = pLeft->x.pList->a[iFld-1].pExpr;
+          }else{
+            pCompare->pLeft = pLeft;
+          }
+          pCompare->pRight = pRight = sqlite3Expr(db, TK_REGISTER, 0);
+          if( pRight ){
+            pRight->iTable = iReg+j+2;
+            sqlite3ExprIfFalse(
+                pParse, pCompare, pLevel->addrCont, SQLITE_JUMPIFNULL
+            );
+          }
+          pCompare->pLeft = 0;
+        }
+        sqlite3ExprDelete(db, pCompare);
+      }
+    }
+
+    /* These registers need to be preserved in case there is an IN operator
+    ** loop.  So we could deallocate the registers here (and potentially
+    ** reuse them later) if (pLoop->wsFlags & WHERE_IN_ABLE)==0.  But it seems
+    ** simpler and safer to simply not reuse the registers.
+    **
+    **    sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2);
+    */
+  }else
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+  if( (pLoop->wsFlags & WHERE_IPK)!=0
+   && (pLoop->wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_EQ))!=0
+  ){
+    /* Case 2:  We can directly reference a single row using an
+    **          equality comparison against the ROWID field.  Or
+    **          we reference multiple rows using a "rowid IN (...)"
+    **          construct.
+    */
+    assert( pLoop->u.btree.nEq==1 );
+    pTerm = pLoop->aLTerm[0];
+    assert( pTerm!=0 );
+    assert( pTerm->pExpr!=0 );
+    testcase( pTerm->wtFlags & TERM_VIRTUAL );
+    iReleaseReg = ++pParse->nMem;
+    iRowidReg = codeEqualityTerm(pParse, pTerm, pLevel, 0, bRev, iReleaseReg);
+    if( iRowidReg!=iReleaseReg ) sqlite3ReleaseTempReg(pParse, iReleaseReg);
+    addrNxt = pLevel->addrNxt;
+    if( pLevel->regFilter ){
+      sqlite3VdbeAddOp2(v, OP_MustBeInt, iRowidReg, addrNxt);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp4Int(v, OP_Filter, pLevel->regFilter, addrNxt,
+                           iRowidReg, 1);
+      VdbeCoverage(v);
+      filterPullDown(pParse, pWInfo, iLevel, addrNxt, notReady);
+    }
+    sqlite3VdbeAddOp3(v, OP_SeekRowid, iCur, addrNxt, iRowidReg);
+    VdbeCoverage(v);
+    pLevel->op = OP_Noop;
+  }else if( (pLoop->wsFlags & WHERE_IPK)!=0
+         && (pLoop->wsFlags & WHERE_COLUMN_RANGE)!=0
+  ){
+    /* Case 3:  We have an inequality comparison against the ROWID field.
+    */
+    int testOp = OP_Noop;
+    int start;
+    int memEndValue = 0;
+    WhereTerm *pStart, *pEnd;
+
+    j = 0;
+    pStart = pEnd = 0;
+    if( pLoop->wsFlags & WHERE_BTM_LIMIT ) pStart = pLoop->aLTerm[j++];
+    if( pLoop->wsFlags & WHERE_TOP_LIMIT ) pEnd = pLoop->aLTerm[j++];
+    assert( pStart!=0 || pEnd!=0 );
+    if( bRev ){
+      pTerm = pStart;
+      pStart = pEnd;
+      pEnd = pTerm;
+    }
+    codeCursorHint(pTabItem, pWInfo, pLevel, pEnd);
+    if( pStart ){
+      Expr *pX;             /* The expression that defines the start bound */
+      int r1, rTemp;        /* Registers for holding the start boundary */
+      int op;               /* Cursor seek operation */
+
+      /* The following constant maps TK_xx codes into corresponding
+      ** seek opcodes.  It depends on a particular ordering of TK_xx
+      */
+      const u8 aMoveOp[] = {
+           /* TK_GT */  OP_SeekGT,
+           /* TK_LE */  OP_SeekLE,
+           /* TK_LT */  OP_SeekLT,
+           /* TK_GE */  OP_SeekGE
+      };
+      assert( TK_LE==TK_GT+1 );      /* Make sure the ordering.. */
+      assert( TK_LT==TK_GT+2 );      /*  ... of the TK_xx values... */
+      assert( TK_GE==TK_GT+3 );      /*  ... is correct. */
+
+      assert( (pStart->wtFlags & TERM_VNULL)==0 );
+      testcase( pStart->wtFlags & TERM_VIRTUAL );
+      pX = pStart->pExpr;
+      assert( pX!=0 );
+      testcase( pStart->leftCursor!=iCur ); /* transitive constraints */
+      if( sqlite3ExprIsVector(pX->pRight) ){
+        r1 = rTemp = sqlite3GetTempReg(pParse);
+        codeExprOrVector(pParse, pX->pRight, r1, 1);
+        testcase( pX->op==TK_GT );
+        testcase( pX->op==TK_GE );
+        testcase( pX->op==TK_LT );
+        testcase( pX->op==TK_LE );
+        op = aMoveOp[((pX->op - TK_GT - 1) & 0x3) | 0x1];
+        assert( pX->op!=TK_GT || op==OP_SeekGE );
+        assert( pX->op!=TK_GE || op==OP_SeekGE );
+        assert( pX->op!=TK_LT || op==OP_SeekLE );
+        assert( pX->op!=TK_LE || op==OP_SeekLE );
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pX->pRight, &rTemp);
+        disableTerm(pLevel, pStart);
+        op = aMoveOp[(pX->op - TK_GT)];
+      }
+      sqlite3VdbeAddOp3(v, op, iCur, addrBrk, r1);
+      VdbeComment((v, "pk"));
+      VdbeCoverageIf(v, pX->op==TK_GT);
+      VdbeCoverageIf(v, pX->op==TK_LE);
+      VdbeCoverageIf(v, pX->op==TK_LT);
+      VdbeCoverageIf(v, pX->op==TK_GE);
+      sqlite3ReleaseTempReg(pParse, rTemp);
+    }else{
+      sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, addrHalt);
+      VdbeCoverageIf(v, bRev==0);
+      VdbeCoverageIf(v, bRev!=0);
+    }
+    if( pEnd ){
+      Expr *pX;
+      pX = pEnd->pExpr;
+      assert( pX!=0 );
+      assert( (pEnd->wtFlags & TERM_VNULL)==0 );
+      testcase( pEnd->leftCursor!=iCur ); /* Transitive constraints */
+      testcase( pEnd->wtFlags & TERM_VIRTUAL );
+      memEndValue = ++pParse->nMem;
+      codeExprOrVector(pParse, pX->pRight, memEndValue, 1);
+      if( 0==sqlite3ExprIsVector(pX->pRight)
+       && (pX->op==TK_LT || pX->op==TK_GT)
+      ){
+        testOp = bRev ? OP_Le : OP_Ge;
+      }else{
+        testOp = bRev ? OP_Lt : OP_Gt;
+      }
+      if( 0==sqlite3ExprIsVector(pX->pRight) ){
+        disableTerm(pLevel, pEnd);
+      }
+    }
+    start = sqlite3VdbeCurrentAddr(v);
+    pLevel->op = bRev ? OP_Prev : OP_Next;
+    pLevel->p1 = iCur;
+    pLevel->p2 = start;
+    assert( pLevel->p5==0 );
+    if( testOp!=OP_Noop ){
+      iRowidReg = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg);
+      sqlite3VdbeAddOp3(v, testOp, memEndValue, addrBrk, iRowidReg);
+      VdbeCoverageIf(v, testOp==OP_Le);
+      VdbeCoverageIf(v, testOp==OP_Lt);
+      VdbeCoverageIf(v, testOp==OP_Ge);
+      VdbeCoverageIf(v, testOp==OP_Gt);
+      sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC | SQLITE_JUMPIFNULL);
+    }
+  }else if( pLoop->wsFlags & WHERE_INDEXED ){
+    /* Case 4: A scan using an index.
+    **
+    **         The WHERE clause may contain zero or more equality
+    **         terms ("==" or "IN" operators) that refer to the N
+    **         left-most columns of the index. It may also contain
+    **         inequality constraints (>, <, >= or <=) on the indexed
+    **         column that immediately follows the N equalities. Only
+    **         the right-most column can be an inequality - the rest must
+    **         use the "==" and "IN" operators. For example, if the
+    **         index is on (x,y,z), then the following clauses are all
+    **         optimized:
+    **
+    **            x=5
+    **            x=5 AND y=10
+    **            x=5 AND y<10
+    **            x=5 AND y>5 AND y<10
+    **            x=5 AND y=5 AND z<=10
+    **
+    **         The z<10 term of the following cannot be used, only
+    **         the x=5 term:
+    **
+    **            x=5 AND z<10
+    **
+    **         N may be zero if there are inequality constraints.
+    **         If there are no inequality constraints, then N is at
+    **         least one.
+    **
+    **         This case is also used when there are no WHERE clause
+    **         constraints but an index is selected anyway, in order
+    **         to force the output order to conform to an ORDER BY.
+    */
+    static const u8 aStartOp[] = {
+      0,
+      0,
+      OP_Rewind,           /* 2: (!start_constraints && startEq &&  !bRev) */
+      OP_Last,             /* 3: (!start_constraints && startEq &&   bRev) */
+      OP_SeekGT,           /* 4: (start_constraints  && !startEq && !bRev) */
+      OP_SeekLT,           /* 5: (start_constraints  && !startEq &&  bRev) */
+      OP_SeekGE,           /* 6: (start_constraints  &&  startEq && !bRev) */
+      OP_SeekLE            /* 7: (start_constraints  &&  startEq &&  bRev) */
+    };
+    static const u8 aEndOp[] = {
+      OP_IdxGE,            /* 0: (end_constraints && !bRev && !endEq) */
+      OP_IdxGT,            /* 1: (end_constraints && !bRev &&  endEq) */
+      OP_IdxLE,            /* 2: (end_constraints &&  bRev && !endEq) */
+      OP_IdxLT,            /* 3: (end_constraints &&  bRev &&  endEq) */
+    };
+    u16 nEq = pLoop->u.btree.nEq;     /* Number of == or IN terms */
+    u16 nBtm = pLoop->u.btree.nBtm;   /* Length of BTM vector */
+    u16 nTop = pLoop->u.btree.nTop;   /* Length of TOP vector */
+    int regBase;                 /* Base register holding constraint values */
+    WhereTerm *pRangeStart = 0;  /* Inequality constraint at range start */
+    WhereTerm *pRangeEnd = 0;    /* Inequality constraint at range end */
+    int startEq;                 /* True if range start uses ==, >= or <= */
+    int endEq;                   /* True if range end uses ==, >= or <= */
+    int start_constraints;       /* Start of range is constrained */
+    int nConstraint;             /* Number of constraint terms */
+    int iIdxCur;                 /* The VDBE cursor for the index */
+    int nExtraReg = 0;           /* Number of extra registers needed */
+    int op;                      /* Instruction opcode */
+    char *zStartAff;             /* Affinity for start of range constraint */
+    char *zEndAff = 0;           /* Affinity for end of range constraint */
+    u8 bSeekPastNull = 0;        /* True to seek past initial nulls */
+    u8 bStopAtNull = 0;          /* Add condition to terminate at NULLs */
+    int omitTable;               /* True if we use the index only */
+    int regBignull = 0;          /* big-null flag register */
+    int addrSeekScan = 0;        /* Opcode of the OP_SeekScan, if any */
+
+    pIdx = pLoop->u.btree.pIndex;
+    iIdxCur = pLevel->iIdxCur;
+    assert( nEq>=pLoop->nSkip );
+
+    /* Find any inequality constraint terms for the start and end
+    ** of the range.
+    */
+    j = nEq;
+    if( pLoop->wsFlags & WHERE_BTM_LIMIT ){
+      pRangeStart = pLoop->aLTerm[j++];
+      nExtraReg = MAX(nExtraReg, pLoop->u.btree.nBtm);
+      /* Like optimization range constraints always occur in pairs */
+      assert( (pRangeStart->wtFlags & TERM_LIKEOPT)==0 ||
+              (pLoop->wsFlags & WHERE_TOP_LIMIT)!=0 );
+    }
+    if( pLoop->wsFlags & WHERE_TOP_LIMIT ){
+      pRangeEnd = pLoop->aLTerm[j++];
+      nExtraReg = MAX(nExtraReg, pLoop->u.btree.nTop);
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+      if( (pRangeEnd->wtFlags & TERM_LIKEOPT)!=0 ){
+        assert( pRangeStart!=0 );                     /* LIKE opt constraints */
+        assert( pRangeStart->wtFlags & TERM_LIKEOPT );   /* occur in pairs */
+        pLevel->iLikeRepCntr = (u32)++pParse->nMem;
+        sqlite3VdbeAddOp2(v, OP_Integer, 1, (int)pLevel->iLikeRepCntr);
+        VdbeComment((v, "LIKE loop counter"));
+        pLevel->addrLikeRep = sqlite3VdbeCurrentAddr(v);
+        /* iLikeRepCntr actually stores 2x the counter register number.  The
+        ** bottom bit indicates whether the search order is ASC or DESC. */
+        testcase( bRev );
+        testcase( pIdx->aSortOrder[nEq]==SQLITE_SO_DESC );
+        assert( (bRev & ~1)==0 );
+        pLevel->iLikeRepCntr <<=1;
+        pLevel->iLikeRepCntr |= bRev ^ (pIdx->aSortOrder[nEq]==SQLITE_SO_DESC);
+      }
+#endif
+      if( pRangeStart==0 ){
+        j = pIdx->aiColumn[nEq];
+        if( (j>=0 && pIdx->pTable->aCol[j].notNull==0) || j==XN_EXPR ){
+          bSeekPastNull = 1;
+        }
+      }
+    }
+    assert( pRangeEnd==0 || (pRangeEnd->wtFlags & TERM_VNULL)==0 );
+
+    /* If the WHERE_BIGNULL_SORT flag is set, then index column nEq uses
+    ** a non-default "big-null" sort (either ASC NULLS LAST or DESC NULLS
+    ** FIRST). In both cases separate ordered scans are made of those
+    ** index entries for which the column is null and for those for which
+    ** it is not. For an ASC sort, the non-NULL entries are scanned first.
+    ** For DESC, NULL entries are scanned first.
+    */
+    if( (pLoop->wsFlags & (WHERE_TOP_LIMIT|WHERE_BTM_LIMIT))==0
+     && (pLoop->wsFlags & WHERE_BIGNULL_SORT)!=0
+    ){
+      assert( bSeekPastNull==0 && nExtraReg==0 && nBtm==0 && nTop==0 );
+      assert( pRangeEnd==0 && pRangeStart==0 );
+      testcase( pLoop->nSkip>0 );
+      nExtraReg = 1;
+      bSeekPastNull = 1;
+      pLevel->regBignull = regBignull = ++pParse->nMem;
+      if( pLevel->iLeftJoin ){
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, regBignull);
+      }
+      pLevel->addrBignull = sqlite3VdbeMakeLabel(pParse);
+    }
+
+    /* If we are doing a reverse order scan on an ascending index, or
+    ** a forward order scan on a descending index, interchange the
+    ** start and end terms (pRangeStart and pRangeEnd).
+    */
+    if( (nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC)) ){
+      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
+      SWAP(u8, bSeekPastNull, bStopAtNull);
+      SWAP(u8, nBtm, nTop);
+    }
+
+    if( iLevel>0 && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)!=0 ){
+      /* In case OP_SeekScan is used, ensure that the index cursor does not
+      ** point to a valid row for the first iteration of this loop. */
+      sqlite3VdbeAddOp1(v, OP_NullRow, iIdxCur);
+    }
+
+    /* Generate code to evaluate all constraint terms using == or IN
+    ** and store the values of those terms in an array of registers
+    ** starting at regBase.
+    */
+    codeCursorHint(pTabItem, pWInfo, pLevel, pRangeEnd);
+    regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);
+    assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq );
+    if( zStartAff && nTop ){
+      zEndAff = sqlite3DbStrDup(db, &zStartAff[nEq]);
+    }
+    addrNxt = (regBignull ? pLevel->addrBignull : pLevel->addrNxt);
+
+    testcase( pRangeStart && (pRangeStart->eOperator & WO_LE)!=0 );
+    testcase( pRangeStart && (pRangeStart->eOperator & WO_GE)!=0 );
+    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_LE)!=0 );
+    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_GE)!=0 );
+    startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
+    endEq =   !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
+    start_constraints = pRangeStart || nEq>0;
+
+    /* Seek the index cursor to the start of the range. */
+    nConstraint = nEq;
+    if( pRangeStart ){
+      Expr *pRight = pRangeStart->pExpr->pRight;
+      codeExprOrVector(pParse, pRight, regBase+nEq, nBtm);
+      whereLikeOptimizationStringFixup(v, pLevel, pRangeStart);
+      if( (pRangeStart->wtFlags & TERM_VNULL)==0
+       && sqlite3ExprCanBeNull(pRight)
+      ){
+        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
+        VdbeCoverage(v);
+      }
+      if( zStartAff ){
+        updateRangeAffinityStr(pRight, nBtm, &zStartAff[nEq]);
+      }
+      nConstraint += nBtm;
+      testcase( pRangeStart->wtFlags & TERM_VIRTUAL );
+      if( sqlite3ExprIsVector(pRight)==0 ){
+        disableTerm(pLevel, pRangeStart);
+      }else{
+        startEq = 1;
+      }
+      bSeekPastNull = 0;
+    }else if( bSeekPastNull ){
+      startEq = 0;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
+      start_constraints = 1;
+      nConstraint++;
+    }else if( regBignull ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
+      start_constraints = 1;
+      nConstraint++;
+    }
+    codeApplyAffinity(pParse, regBase, nConstraint - bSeekPastNull, zStartAff);
+    if( pLoop->nSkip>0 && nConstraint==pLoop->nSkip ){
+      /* The skip-scan logic inside the call to codeAllEqualityConstraints()
+      ** above has already left the cursor sitting on the correct row,
+      ** so no further seeking is needed */
+    }else{
+      if( regBignull ){
+        sqlite3VdbeAddOp2(v, OP_Integer, 1, regBignull);
+        VdbeComment((v, "NULL-scan pass ctr"));
+      }
+      if( pLevel->regFilter ){
+        sqlite3VdbeAddOp4Int(v, OP_Filter, pLevel->regFilter, addrNxt,
+                             regBase, nEq);
+        VdbeCoverage(v);
+        filterPullDown(pParse, pWInfo, iLevel, addrNxt, notReady);
+      }
+
+      op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
+      assert( op!=0 );
+      if( (pLoop->wsFlags & WHERE_IN_SEEKSCAN)!=0 && op==OP_SeekGE ){
+        assert( regBignull==0 );
+        /* TUNING:  The OP_SeekScan opcode seeks to reduce the number
+        ** of expensive seek operations by replacing a single seek with
+        ** 1 or more step operations.  The question is, how many steps
+        ** should we try before giving up and going with a seek.  The cost
+        ** of a seek is proportional to the logarithm of the of the number
+        ** of entries in the tree, so basing the number of steps to try
+        ** on the estimated number of rows in the btree seems like a good
+        ** guess. */
+        addrSeekScan = sqlite3VdbeAddOp1(v, OP_SeekScan,
+                                         (pIdx->aiRowLogEst[0]+9)/10);
+        if( pRangeStart || pRangeEnd ){
+          sqlite3VdbeChangeP5(v, 1);
+          sqlite3VdbeChangeP2(v, addrSeekScan, sqlite3VdbeCurrentAddr(v)+1);
+          addrSeekScan = 0;
+        }
+        VdbeCoverage(v);
+      }
+      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
+      VdbeCoverage(v);
+      VdbeCoverageIf(v, op==OP_Rewind);  testcase( op==OP_Rewind );
+      VdbeCoverageIf(v, op==OP_Last);    testcase( op==OP_Last );
+      VdbeCoverageIf(v, op==OP_SeekGT);  testcase( op==OP_SeekGT );
+      VdbeCoverageIf(v, op==OP_SeekGE);  testcase( op==OP_SeekGE );
+      VdbeCoverageIf(v, op==OP_SeekLE);  testcase( op==OP_SeekLE );
+      VdbeCoverageIf(v, op==OP_SeekLT);  testcase( op==OP_SeekLT );
+
+      assert( bSeekPastNull==0 || bStopAtNull==0 );
+      if( regBignull ){
+        assert( bSeekPastNull==1 || bStopAtNull==1 );
+        assert( bSeekPastNull==!bStopAtNull );
+        assert( bStopAtNull==startEq );
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+2);
+        op = aStartOp[(nConstraint>1)*4 + 2 + bRev];
+        sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase,
+                             nConstraint-startEq);
+        VdbeCoverage(v);
+        VdbeCoverageIf(v, op==OP_Rewind);  testcase( op==OP_Rewind );
+        VdbeCoverageIf(v, op==OP_Last);    testcase( op==OP_Last );
+        VdbeCoverageIf(v, op==OP_SeekGE);  testcase( op==OP_SeekGE );
+        VdbeCoverageIf(v, op==OP_SeekLE);  testcase( op==OP_SeekLE );
+        assert( op==OP_Rewind || op==OP_Last || op==OP_SeekGE || op==OP_SeekLE);
+      }
+    }
+
+    /* Load the value for the inequality constraint at the end of the
+    ** range (if any).
+    */
+    nConstraint = nEq;
+    assert( pLevel->p2==0 );
+    if( pRangeEnd ){
+      Expr *pRight = pRangeEnd->pExpr->pRight;
+      assert( addrSeekScan==0 );
+      codeExprOrVector(pParse, pRight, regBase+nEq, nTop);
+      whereLikeOptimizationStringFixup(v, pLevel, pRangeEnd);
+      if( (pRangeEnd->wtFlags & TERM_VNULL)==0
+       && sqlite3ExprCanBeNull(pRight)
+      ){
+        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
+        VdbeCoverage(v);
+      }
+      if( zEndAff ){
+        updateRangeAffinityStr(pRight, nTop, zEndAff);
+        codeApplyAffinity(pParse, regBase+nEq, nTop, zEndAff);
+      }else{
+        assert( pParse->db->mallocFailed );
+      }
+      nConstraint += nTop;
+      testcase( pRangeEnd->wtFlags & TERM_VIRTUAL );
+
+      if( sqlite3ExprIsVector(pRight)==0 ){
+        disableTerm(pLevel, pRangeEnd);
+      }else{
+        endEq = 1;
+      }
+    }else if( bStopAtNull ){
+      if( regBignull==0 ){
+        sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
+        endEq = 0;
+      }
+      nConstraint++;
+    }
+    if( zStartAff ) sqlite3DbNNFreeNN(db, zStartAff);
+    if( zEndAff ) sqlite3DbNNFreeNN(db, zEndAff);
+
+    /* Top of the loop body */
+    pLevel->p2 = sqlite3VdbeCurrentAddr(v);
+
+    /* Check if the index cursor is past the end of the range. */
+    if( nConstraint ){
+      if( regBignull ){
+        /* Except, skip the end-of-range check while doing the NULL-scan */
+        sqlite3VdbeAddOp2(v, OP_IfNot, regBignull, sqlite3VdbeCurrentAddr(v)+3);
+        VdbeComment((v, "If NULL-scan 2nd pass"));
+        VdbeCoverage(v);
+      }
+      op = aEndOp[bRev*2 + endEq];
+      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
+      testcase( op==OP_IdxGT );  VdbeCoverageIf(v, op==OP_IdxGT );
+      testcase( op==OP_IdxGE );  VdbeCoverageIf(v, op==OP_IdxGE );
+      testcase( op==OP_IdxLT );  VdbeCoverageIf(v, op==OP_IdxLT );
+      testcase( op==OP_IdxLE );  VdbeCoverageIf(v, op==OP_IdxLE );
+      if( addrSeekScan ) sqlite3VdbeJumpHere(v, addrSeekScan);
+    }
+    if( regBignull ){
+      /* During a NULL-scan, check to see if we have reached the end of
+      ** the NULLs */
+      assert( bSeekPastNull==!bStopAtNull );
+      assert( bSeekPastNull+bStopAtNull==1 );
+      assert( nConstraint+bSeekPastNull>0 );
+      sqlite3VdbeAddOp2(v, OP_If, regBignull, sqlite3VdbeCurrentAddr(v)+2);
+      VdbeComment((v, "If NULL-scan 1st pass"));
+      VdbeCoverage(v);
+      op = aEndOp[bRev*2 + bSeekPastNull];
+      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase,
+                           nConstraint+bSeekPastNull);
+      testcase( op==OP_IdxGT );  VdbeCoverageIf(v, op==OP_IdxGT );
+      testcase( op==OP_IdxGE );  VdbeCoverageIf(v, op==OP_IdxGE );
+      testcase( op==OP_IdxLT );  VdbeCoverageIf(v, op==OP_IdxLT );
+      testcase( op==OP_IdxLE );  VdbeCoverageIf(v, op==OP_IdxLE );
+    }
+
+    if( (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0 ){
+      sqlite3VdbeAddOp3(v, OP_SeekHit, iIdxCur, nEq, nEq);
+    }
+
+    /* Seek the table cursor, if required */
+    omitTable = (pLoop->wsFlags & WHERE_IDX_ONLY)!=0
+           && (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0;
+    if( omitTable ){
+      /* pIdx is a covering index.  No need to access the main table. */
+    }else if( HasRowid(pIdx->pTable) ){
+      codeDeferredSeek(pWInfo, pIdx, iCur, iIdxCur);
+    }else if( iCur!=iIdxCur ){
+      Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable);
+      iRowidReg = sqlite3GetTempRange(pParse, pPk->nKeyCol);
+      for(j=0; j<pPk->nKeyCol; j++){
+        k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[j]);
+        sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, iRowidReg+j);
+      }
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, iCur, addrCont,
+                           iRowidReg, pPk->nKeyCol); VdbeCoverage(v);
+    }
+
+    if( pLevel->iLeftJoin==0 ){
+      /* If a partial index is driving the loop, try to eliminate WHERE clause
+      ** terms from the query that must be true due to the WHERE clause of
+      ** the partial index.
+      **
+      ** 2019-11-02 ticket 623eff57e76d45f6: This optimization does not work
+      ** for a LEFT JOIN.
+      */
+      if( pIdx->pPartIdxWhere ){
+        whereApplyPartialIndexConstraints(pIdx->pPartIdxWhere, iCur, pWC);
+      }
+    }else{
+      testcase( pIdx->pPartIdxWhere );
+      /* The following assert() is not a requirement, merely an observation:
+      ** The OR-optimization doesn't work for the right hand table of
+      ** a LEFT JOIN: */
+      assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0 );
+    }
+
+    /* Record the instruction used to terminate the loop. */
+    if( (pLoop->wsFlags & WHERE_ONEROW)
+     || (pLevel->u.in.nIn && regBignull==0 && whereLoopIsOneRow(pLoop))
+    ){
+      pLevel->op = OP_Noop;
+    }else if( bRev ){
+      pLevel->op = OP_Prev;
+    }else{
+      pLevel->op = OP_Next;
+    }
+    pLevel->p1 = iIdxCur;
+    pLevel->p3 = (pLoop->wsFlags&WHERE_UNQ_WANTED)!=0 ? 1:0;
+    if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){
+      pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
+    }else{
+      assert( pLevel->p5==0 );
+    }
+    if( omitTable ) pIdx = 0;
+  }else
+
+#ifndef SQLITE_OMIT_OR_OPTIMIZATION
+  if( pLoop->wsFlags & WHERE_MULTI_OR ){
+    /* Case 5:  Two or more separately indexed terms connected by OR
+    **
+    ** Example:
+    **
+    **   CREATE TABLE t1(a,b,c,d);
+    **   CREATE INDEX i1 ON t1(a);
+    **   CREATE INDEX i2 ON t1(b);
+    **   CREATE INDEX i3 ON t1(c);
+    **
+    **   SELECT * FROM t1 WHERE a=5 OR b=7 OR (c=11 AND d=13)
+    **
+    ** In the example, there are three indexed terms connected by OR.
+    ** The top of the loop looks like this:
+    **
+    **          Null       1                # Zero the rowset in reg 1
+    **
+    ** Then, for each indexed term, the following. The arguments to
+    ** RowSetTest are such that the rowid of the current row is inserted
+    ** into the RowSet. If it is already present, control skips the
+    ** Gosub opcode and jumps straight to the code generated by WhereEnd().
+    **
+    **        sqlite3WhereBegin(<term>)
+    **          RowSetTest                  # Insert rowid into rowset
+    **          Gosub      2 A
+    **        sqlite3WhereEnd()
+    **
+    ** Following the above, code to terminate the loop. Label A, the target
+    ** of the Gosub above, jumps to the instruction right after the Goto.
+    **
+    **          Null       1                # Zero the rowset in reg 1
+    **          Goto       B                # The loop is finished.
+    **
+    **       A: <loop body>                 # Return data, whatever.
+    **
+    **          Return     2                # Jump back to the Gosub
+    **
+    **       B: <after the loop>
+    **
+    ** Added 2014-05-26: If the table is a WITHOUT ROWID table, then
+    ** use an ephemeral index instead of a RowSet to record the primary
+    ** keys of the rows we have already seen.
+    **
+    */
+    WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
+    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */
+    Index *pCov = 0;             /* Potential covering index (or NULL) */
+    int iCovCur = pParse->nTab++;  /* Cursor used for index scans (if any) */
+
+    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
+    int regRowset = 0;                        /* Register for RowSet object */
+    int regRowid = 0;                         /* Register holding rowid */
+    int iLoopBody = sqlite3VdbeMakeLabel(pParse);/* Start of loop body */
+    int iRetInit;                             /* Address of regReturn init */
+    int untestedTerms = 0;             /* Some terms not completely tested */
+    int ii;                            /* Loop counter */
+    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
+    Table *pTab = pTabItem->pSTab;
+
+    pTerm = pLoop->aLTerm[0];
+    assert( pTerm!=0 );
+    assert( pTerm->eOperator & WO_OR );
+    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
+    pOrWc = &pTerm->u.pOrInfo->wc;
+    pLevel->op = OP_Return;
+    pLevel->p1 = regReturn;
+
+    /* Set up a new SrcList in pOrTab containing the table being scanned
+    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
+    ** This becomes the SrcList in the recursive call to sqlite3WhereBegin().
+    */
+    if( pWInfo->nLevel>1 ){
+      int nNotReady;                 /* The number of notReady tables */
+      SrcItem *origSrc;              /* Original list of tables */
+      nNotReady = pWInfo->nLevel - iLevel - 1;
+      pOrTab = sqlite3DbMallocRawNN(db,
+                            sizeof(*pOrTab)+ nNotReady*sizeof(pOrTab->a[0]));
+      if( pOrTab==0 ) return notReady;
+      pOrTab->nAlloc = (u8)(nNotReady + 1);
+      pOrTab->nSrc = pOrTab->nAlloc;
+      memcpy(pOrTab->a, pTabItem, sizeof(*pTabItem));
+      origSrc = pWInfo->pTabList->a;
+      for(k=1; k<=nNotReady; k++){
+        memcpy(&pOrTab->a[k], &origSrc[pLevel[k].iFrom], sizeof(pOrTab->a[k]));
+      }
+    }else{
+      pOrTab = pWInfo->pTabList;
+    }
+
+    /* Initialize the rowset register to contain NULL. An SQL NULL is
+    ** equivalent to an empty rowset.  Or, create an ephemeral index
+    ** capable of holding primary keys in the case of a WITHOUT ROWID.
+    **
+    ** Also initialize regReturn to contain the address of the instruction
+    ** immediately following the OP_Return at the bottom of the loop. This
+    ** is required in a few obscure LEFT JOIN cases where control jumps
+    ** over the top of the loop into the body of it. In this case the
+    ** correct response for the end-of-loop code (the OP_Return) is to
+    ** fall through to the next instruction, just as an OP_Next does if
+    ** called on an uninitialized cursor.
+    */
+    if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
+      if( HasRowid(pTab) ){
+        regRowset = ++pParse->nMem;
+        sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset);
+      }else{
+        Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+        regRowset = pParse->nTab++;
+        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, regRowset, pPk->nKeyCol);
+        sqlite3VdbeSetP4KeyInfo(pParse, pPk);
+      }
+      regRowid = ++pParse->nMem;
+    }
+    iRetInit = sqlite3VdbeAddOp2(v, OP_Integer, 0, regReturn);
+
+    /* If the original WHERE clause is z of the form:  (x1 OR x2 OR ...) AND y
+    ** Then for every term xN, evaluate as the subexpression: xN AND y
+    ** That way, terms in y that are factored into the disjunction will
+    ** be picked up by the recursive calls to sqlite3WhereBegin() below.
+    **
+    ** Actually, each subexpression is converted to "xN AND w" where w is
+    ** the "interesting" terms of z - terms that did not originate in the
+    ** ON or USING clause of a LEFT JOIN, and terms that are usable as
+    ** indices.
+    **
+    ** This optimization also only applies if the (x1 OR x2 OR ...) term
+    ** is not contained in the ON clause of a LEFT JOIN.
+    ** See ticket http://www.sqlite.org/src/info/f2369304e4
+    **
+    ** 2022-02-04:  Do not push down slices of a row-value comparison.
+    ** In other words, "w" or "y" may not be a slice of a vector.  Otherwise,
+    ** the initialization of the right-hand operand of the vector comparison
+    ** might not occur, or might occur only in an OR branch that is not
+    ** taken.  dbsqlfuzz 80a9fade844b4fb43564efc972bcb2c68270f5d1.
+    **
+    ** 2022-03-03:  Do not push down expressions that involve subqueries.
+    ** The subquery might get coded as a subroutine.  Any table-references
+    ** in the subquery might be resolved to index-references for the index on
+    ** the OR branch in which the subroutine is coded.  But if the subroutine
+    ** is invoked from a different OR branch that uses a different index, such
+    ** index-references will not work.  tag-20220303a
+    ** https://sqlite.org/forum/forumpost/36937b197273d403
+    */
+    if( pWC->nTerm>1 ){
+      int iTerm;
+      for(iTerm=0; iTerm<pWC->nTerm; iTerm++){
+        Expr *pExpr = pWC->a[iTerm].pExpr;
+        if( &pWC->a[iTerm] == pTerm ) continue;
+        testcase( pWC->a[iTerm].wtFlags & TERM_VIRTUAL );
+        testcase( pWC->a[iTerm].wtFlags & TERM_CODED );
+        testcase( pWC->a[iTerm].wtFlags & TERM_SLICE );
+        if( (pWC->a[iTerm].wtFlags & (TERM_VIRTUAL|TERM_CODED|TERM_SLICE))!=0 ){
+          continue;
+        }
+        if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue;
+        if( ExprHasProperty(pExpr, EP_Subquery) ) continue;  /* tag-20220303a */
+        pExpr = sqlite3ExprDup(db, pExpr, 0);
+        pAndExpr = sqlite3ExprAnd(pParse, pAndExpr, pExpr);
+      }
+      if( pAndExpr ){
+        /* The extra 0x10000 bit on the opcode is masked off and does not
+        ** become part of the new Expr.op.  However, it does make the
+        ** op==TK_AND comparison inside of sqlite3PExpr() false, and this
+        ** prevents sqlite3PExpr() from applying the AND short-circuit
+        ** optimization, which we do not want here. */
+        pAndExpr = sqlite3PExpr(pParse, TK_AND|0x10000, 0, pAndExpr);
+      }
+    }
+
+    /* Run a separate WHERE clause for each term of the OR clause.  After
+    ** eliminating duplicates from other WHERE clauses, the action for each
+    ** sub-WHERE clause is to to invoke the main loop body as a subroutine.
+    */
+    ExplainQueryPlan((pParse, 1, "MULTI-INDEX OR"));
+    for(ii=0; ii<pOrWc->nTerm; ii++){
+      WhereTerm *pOrTerm = &pOrWc->a[ii];
+      if( pOrTerm->leftCursor==iCur || (pOrTerm->eOperator & WO_AND)!=0 ){
+        WhereInfo *pSubWInfo;           /* Info for single OR-term scan */
+        Expr *pOrExpr = pOrTerm->pExpr; /* Current OR clause term */
+        Expr *pDelete;                  /* Local copy of OR clause term */
+        int jmp1 = 0;                   /* Address of jump operation */
+        testcase( (pTabItem[0].fg.jointype & JT_LEFT)!=0
+               && !ExprHasProperty(pOrExpr, EP_OuterON)
+        ); /* See TH3 vtab25.400 and ticket 614b25314c766238 */
+        pDelete = pOrExpr = sqlite3ExprDup(db, pOrExpr, 0);
+        if( db->mallocFailed ){
+          sqlite3ExprDelete(db, pDelete);
+          continue;
+        }
+        if( pAndExpr ){
+          pAndExpr->pLeft = pOrExpr;
+          pOrExpr = pAndExpr;
+        }
+        /* Loop through table entries that match term pOrTerm. */
+        ExplainQueryPlan((pParse, 1, "INDEX %d", ii+1));
+        WHERETRACE(0xffffffff, ("Subplan for OR-clause:\n"));
+        pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0, 0,
+                                      WHERE_OR_SUBCLAUSE, iCovCur);
+        assert( pSubWInfo || pParse->nErr );
+        if( pSubWInfo ){
+          WhereLoop *pSubLoop;
+          int addrExplain = sqlite3WhereExplainOneScan(
+              pParse, pOrTab, &pSubWInfo->a[0], 0
+          );
+          sqlite3WhereAddScanStatus(v, pOrTab, &pSubWInfo->a[0], addrExplain);
+
+          /* This is the sub-WHERE clause body.  First skip over
+          ** duplicate rows from prior sub-WHERE clauses, and record the
+          ** rowid (or PRIMARY KEY) for the current row so that the same
+          ** row will be skipped in subsequent sub-WHERE clauses.
+          */
+          if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
+            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
+            if( HasRowid(pTab) ){
+              sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, regRowid);
+              jmp1 = sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, 0,
+                                          regRowid, iSet);
+              VdbeCoverage(v);
+            }else{
+              Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+              int nPk = pPk->nKeyCol;
+              int iPk;
+              int r;
+
+              /* Read the PK into an array of temp registers. */
+              r = sqlite3GetTempRange(pParse, nPk);
+              for(iPk=0; iPk<nPk; iPk++){
+                int iCol = pPk->aiColumn[iPk];
+                sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+iPk);
+              }
+
+              /* Check if the temp table already contains this key. If so,
+              ** the row has already been included in the result set and
+              ** can be ignored (by jumping past the Gosub below). Otherwise,
+              ** insert the key into the temp table and proceed with processing
+              ** the row.
+              **
+              ** Use some of the same optimizations as OP_RowSetTest: If iSet
+              ** is zero, assume that the key cannot already be present in
+              ** the temp table. And if iSet is -1, assume that there is no
+              ** need to insert the key into the temp table, as it will never
+              ** be tested for.  */
+              if( iSet ){
+                jmp1 = sqlite3VdbeAddOp4Int(v, OP_Found, regRowset, 0, r, nPk);
+                VdbeCoverage(v);
+              }
+              if( iSet>=0 ){
+                sqlite3VdbeAddOp3(v, OP_MakeRecord, r, nPk, regRowid);
+                sqlite3VdbeAddOp4Int(v, OP_IdxInsert, regRowset, regRowid,
+                                     r, nPk);
+                if( iSet ) sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+              }
+
+              /* Release the array of temp registers */
+              sqlite3ReleaseTempRange(pParse, r, nPk);
+            }
+          }
+
+          /* Invoke the main loop body as a subroutine */
+          sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);
+
+          /* Jump here (skipping the main loop body subroutine) if the
+          ** current sub-WHERE row is a duplicate from prior sub-WHEREs. */
+          if( jmp1 ) sqlite3VdbeJumpHere(v, jmp1);
+
+          /* The pSubWInfo->untestedTerms flag means that this OR term
+          ** contained one or more AND term from a notReady table.  The
+          ** terms from the notReady table could not be tested and will
+          ** need to be tested later.
+          */
+          if( pSubWInfo->untestedTerms ) untestedTerms = 1;
+
+          /* If all of the OR-connected terms are optimized using the same
+          ** index, and the index is opened using the same cursor number
+          ** by each call to sqlite3WhereBegin() made by this loop, it may
+          ** be possible to use that index as a covering index.
+          **
+          ** If the call to sqlite3WhereBegin() above resulted in a scan that
+          ** uses an index, and this is either the first OR-connected term
+          ** processed or the index is the same as that used by all previous
+          ** terms, set pCov to the candidate covering index. Otherwise, set
+          ** pCov to NULL to indicate that no candidate covering index will
+          ** be available.
+          */
+          pSubLoop = pSubWInfo->a[0].pWLoop;
+          assert( (pSubLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
+          if( (pSubLoop->wsFlags & WHERE_INDEXED)!=0
+           && (ii==0 || pSubLoop->u.btree.pIndex==pCov)
+           && (HasRowid(pTab) || !IsPrimaryKeyIndex(pSubLoop->u.btree.pIndex))
+          ){
+            assert( pSubWInfo->a[0].iIdxCur==iCovCur );
+            pCov = pSubLoop->u.btree.pIndex;
+          }else{
+            pCov = 0;
+          }
+          if( sqlite3WhereUsesDeferredSeek(pSubWInfo) ){
+            pWInfo->bDeferredSeek = 1;
+          }
+
+          /* Finish the loop through table entries that match term pOrTerm. */
+          sqlite3WhereEnd(pSubWInfo);
+          ExplainQueryPlanPop(pParse);
+        }
+        sqlite3ExprDelete(db, pDelete);
+      }
+    }
+    ExplainQueryPlanPop(pParse);
+    assert( pLevel->pWLoop==pLoop );
+    assert( (pLoop->wsFlags & WHERE_MULTI_OR)!=0 );
+    assert( (pLoop->wsFlags & WHERE_IN_ABLE)==0 );
+    pLevel->u.pCoveringIdx = pCov;
+    if( pCov ) pLevel->iIdxCur = iCovCur;
+    if( pAndExpr ){
+      pAndExpr->pLeft = 0;
+      sqlite3ExprDelete(db, pAndExpr);
+    }
+    sqlite3VdbeChangeP1(v, iRetInit, sqlite3VdbeCurrentAddr(v));
+    sqlite3VdbeGoto(v, pLevel->addrBrk);
+    sqlite3VdbeResolveLabel(v, iLoopBody);
+
+    /* Set the P2 operand of the OP_Return opcode that will end the current
+    ** loop to point to this spot, which is the top of the next containing
+    ** loop.  The byte-code formatter will use that P2 value as a hint to
+    ** indent everything in between the this point and the final OP_Return.
+    ** See tag-20220407a in vdbe.c and shell.c */
+    assert( pLevel->op==OP_Return );
+    pLevel->p2 = sqlite3VdbeCurrentAddr(v);
+
+    if( pWInfo->nLevel>1 ){ sqlite3DbFreeNN(db, pOrTab); }
+    if( !untestedTerms ) disableTerm(pLevel, pTerm);
+  }else
+#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
+
+  {
+    /* Case 6:  There is no usable index.  We must do a complete
+    **          scan of the entire table.
+    */
+    static const u8 aStep[] = { OP_Next, OP_Prev };
+    static const u8 aStart[] = { OP_Rewind, OP_Last };
+    assert( bRev==0 || bRev==1 );
+    if( pTabItem->fg.isRecursive ){
+      /* Tables marked isRecursive have only a single row that is stored in
+      ** a pseudo-cursor.  No need to Rewind or Next such cursors. */
+      pLevel->op = OP_Noop;
+    }else{
+      codeCursorHint(pTabItem, pWInfo, pLevel, 0);
+      pLevel->op = aStep[bRev];
+      pLevel->p1 = iCur;
+      pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrHalt);
+      VdbeCoverageIf(v, bRev==0);
+      VdbeCoverageIf(v, bRev!=0);
+      pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
+    }
+  }
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  pLevel->addrVisit = sqlite3VdbeCurrentAddr(v);
+#endif
+
+  /* Insert code to test every subexpression that can be completely
+  ** computed using the current set of tables.
+  **
+  ** This loop may run between one and three times, depending on the
+  ** constraints to be generated. The value of stack variable iLoop
+  ** determines the constraints coded by each iteration, as follows:
+  **
+  ** iLoop==1: Code only expressions that are entirely covered by pIdx.
+  ** iLoop==2: Code remaining expressions that do not contain correlated
+  **           sub-queries.
+  ** iLoop==3: Code all remaining expressions.
+  **
+  ** An effort is made to skip unnecessary iterations of the loop.
+  **
+  ** This optimization of causing simple query restrictions to occur before
+  ** more complex one is call the "push-down" optimization in MySQL.  Here
+  ** in SQLite, the name is "MySQL push-down", since there is also another
+  ** totally unrelated optimization called "WHERE-clause push-down".
+  ** Sometimes the qualifier is omitted, resulting in an ambiguity, so beware.
+  */
+  iLoop = (pIdx ? 1 : 2);
+  do{
+    int iNext = 0;                /* Next value for iLoop */
+    for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
+      Expr *pE;
+      int skipLikeAddr = 0;
+      testcase( pTerm->wtFlags & TERM_VIRTUAL );
+      testcase( pTerm->wtFlags & TERM_CODED );
+      if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+      if( (pTerm->prereqAll & pLevel->notReady)!=0 ){
+        testcase( pWInfo->untestedTerms==0
+            && (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)!=0 );
+        pWInfo->untestedTerms = 1;
+        continue;
+      }
+      pE = pTerm->pExpr;
+      assert( pE!=0 );
+      if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT) ){
+        if( !ExprHasProperty(pE,EP_OuterON|EP_InnerON) ){
+          /* Defer processing WHERE clause constraints until after outer
+          ** join processing.  tag-20220513a */
+          continue;
+        }else if( (pTabItem->fg.jointype & JT_LEFT)==JT_LEFT
+               && !ExprHasProperty(pE,EP_OuterON) ){
+          continue;
+        }else{
+          Bitmask m = sqlite3WhereGetMask(&pWInfo->sMaskSet, pE->w.iJoin);
+          if( m & pLevel->notReady ){
+            /* An ON clause that is not ripe */
+            continue;
+          }
+        }
+      }
+      if( iLoop==1 && !sqlite3ExprCoveredByIndex(pE, pLevel->iTabCur, pIdx) ){
+        iNext = 2;
+        continue;
+      }
+      if( iLoop<3 && (pTerm->wtFlags & TERM_VARSELECT) ){
+        if( iNext==0 ) iNext = 3;
+        continue;
+      }
+
+      if( (pTerm->wtFlags & TERM_LIKECOND)!=0 ){
+        /* If the TERM_LIKECOND flag is set, that means that the range search
+        ** is sufficient to guarantee that the LIKE operator is true, so we
+        ** can skip the call to the like(A,B) function.  But this only works
+        ** for strings.  So do not skip the call to the function on the pass
+        ** that compares BLOBs. */
+#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+        continue;
+#else
+        u32 x = pLevel->iLikeRepCntr;
+        if( x>0 ){
+          skipLikeAddr = sqlite3VdbeAddOp1(v, (x&1)?OP_IfNot:OP_If,(int)(x>>1));
+          VdbeCoverageIf(v, (x&1)==1);
+          VdbeCoverageIf(v, (x&1)==0);
+        }
+#endif
+      }
+#ifdef WHERETRACE_ENABLED /* 0xffffffff */
+      if( sqlite3WhereTrace ){
+        VdbeNoopComment((v, "WhereTerm[%d] (%p) priority=%d",
+                         pWC->nTerm-j, pTerm, iLoop));
+      }
+      if( sqlite3WhereTrace & 0x4000 ){
+        sqlite3DebugPrintf("Coding auxiliary constraint:\n");
+        sqlite3WhereTermPrint(pTerm, pWC->nTerm-j);
+      }
+#endif
+      sqlite3ExprIfFalse(pParse, pE, addrCont, SQLITE_JUMPIFNULL);
+      if( skipLikeAddr ) sqlite3VdbeJumpHere(v, skipLikeAddr);
+      pTerm->wtFlags |= TERM_CODED;
+    }
+    iLoop = iNext;
+  }while( iLoop>0 );
+
+  /* Insert code to test for implied constraints based on transitivity
+  ** of the "==" operator.
+  **
+  ** Example: If the WHERE clause contains "t1.a=t2.b" and "t2.b=123"
+  ** and we are coding the t1 loop and the t2 loop has not yet coded,
+  ** then we cannot use the "t1.a=t2.b" constraint, but we can code
+  ** the implied "t1.a=123" constraint.
+  */
+  for(pTerm=pWC->a, j=pWC->nBase; j>0; j--, pTerm++){
+    Expr *pE, sEAlt;
+    WhereTerm *pAlt;
+    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+    if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) continue;
+    if( (pTerm->eOperator & WO_EQUIV)==0 ) continue;
+    if( pTerm->leftCursor!=iCur ) continue;
+    if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT) ) continue;
+    pE = pTerm->pExpr;
+#ifdef WHERETRACE_ENABLED /* 0x4001 */
+    if( (sqlite3WhereTrace & 0x4001)==0x4001 ){
+      sqlite3DebugPrintf("Coding transitive constraint:\n");
+      sqlite3WhereTermPrint(pTerm, pWC->nTerm-j);
+    }
+#endif
+    assert( !ExprHasProperty(pE, EP_OuterON) );
+    assert( (pTerm->prereqRight & pLevel->notReady)!=0 );
+    assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+    pAlt = sqlite3WhereFindTerm(pWC, iCur, pTerm->u.x.leftColumn, notReady,
+                    WO_EQ|WO_IN|WO_IS, 0);
+    if( pAlt==0 ) continue;
+    if( pAlt->wtFlags & (TERM_CODED) ) continue;
+    if( (pAlt->eOperator & WO_IN)
+     && ExprUseXSelect(pAlt->pExpr)
+     && (pAlt->pExpr->x.pSelect->pEList->nExpr>1)
+    ){
+      continue;
+    }
+    testcase( pAlt->eOperator & WO_EQ );
+    testcase( pAlt->eOperator & WO_IS );
+    testcase( pAlt->eOperator & WO_IN );
+    VdbeModuleComment((v, "begin transitive constraint"));
+    sEAlt = *pAlt->pExpr;
+    sEAlt.pLeft = pE->pLeft;
+    sqlite3ExprIfFalse(pParse, &sEAlt, addrCont, SQLITE_JUMPIFNULL);
+    pAlt->wtFlags |= TERM_CODED;
+  }
+
+  /* For a RIGHT OUTER JOIN, record the fact that the current row has
+  ** been matched at least once.
+  */
+  if( pLevel->pRJ ){
+    Table *pTab;
+    int nPk;
+    int r;
+    int jmp1 = 0;
+    WhereRightJoin *pRJ = pLevel->pRJ;
+
+    /* pTab is the right-hand table of the RIGHT JOIN.  Generate code that
+    ** will record that the current row of that table has been matched at
+    ** least once.  This is accomplished by storing the PK for the row in
+    ** both the iMatch index and the regBloom Bloom filter.
+    */
+    pTab = pWInfo->pTabList->a[pLevel->iFrom].pSTab;
+    if( HasRowid(pTab) ){
+      r = sqlite3GetTempRange(pParse, 2);
+      sqlite3ExprCodeGetColumnOfTable(v, pTab, pLevel->iTabCur, -1, r+1);
+      nPk = 1;
+    }else{
+      int iPk;
+      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+      nPk = pPk->nKeyCol;
+      r = sqlite3GetTempRange(pParse, nPk+1);
+      for(iPk=0; iPk<nPk; iPk++){
+        int iCol = pPk->aiColumn[iPk];
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+1+iPk);
+      }
+    }
+    jmp1 = sqlite3VdbeAddOp4Int(v, OP_Found, pRJ->iMatch, 0, r+1, nPk);
+    VdbeCoverage(v);
+    VdbeComment((v, "match against %s", pTab->zName));
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, r+1, nPk, r);
+    sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pRJ->iMatch, r, r+1, nPk);
+    sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pRJ->regBloom, 0, r+1, nPk);
+    sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+    sqlite3VdbeJumpHere(v, jmp1);
+    sqlite3ReleaseTempRange(pParse, r, nPk+1);
+  }
+
+  /* For a LEFT OUTER JOIN, generate code that will record the fact that
+  ** at least one row of the right table has matched the left table.
+  */
+  if( pLevel->iLeftJoin ){
+    pLevel->addrFirst = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
+    VdbeComment((v, "record LEFT JOIN hit"));
+    if( pLevel->pRJ==0 ){
+      goto code_outer_join_constraints; /* WHERE clause constraints */
+    }
+  }
+
+  if( pLevel->pRJ ){
+    /* Create a subroutine used to process all interior loops and code
+    ** of the RIGHT JOIN.  During normal operation, the subroutine will
+    ** be in-line with the rest of the code.  But at the end, a separate
+    ** loop will run that invokes this subroutine for unmatched rows
+    ** of pTab, with all tables to left begin set to NULL.
+    */
+    WhereRightJoin *pRJ = pLevel->pRJ;
+    sqlite3VdbeAddOp2(v, OP_BeginSubrtn, 0, pRJ->regReturn);
+    pRJ->addrSubrtn = sqlite3VdbeCurrentAddr(v);
+    assert( pParse->withinRJSubrtn < 255 );
+    pParse->withinRJSubrtn++;
+
+    /* WHERE clause constraints must be deferred until after outer join
+    ** row elimination has completed, since WHERE clause constraints apply
+    ** to the results of the OUTER JOIN.  The following loop generates the
+    ** appropriate WHERE clause constraint checks.  tag-20220513a.
+    */
+  code_outer_join_constraints:
+    for(pTerm=pWC->a, j=0; j<pWC->nBase; j++, pTerm++){
+      testcase( pTerm->wtFlags & TERM_VIRTUAL );
+      testcase( pTerm->wtFlags & TERM_CODED );
+      if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+      if( (pTerm->prereqAll & pLevel->notReady)!=0 ){
+        assert( pWInfo->untestedTerms );
+        continue;
+      }
+      if( pTabItem->fg.jointype & JT_LTORJ ) continue;
+      assert( pTerm->pExpr );
+      sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
+      pTerm->wtFlags |= TERM_CODED;
+    }
+  }
+
+#if WHERETRACE_ENABLED /* 0x4001 */
+  if( sqlite3WhereTrace & 0x4000 ){
+    sqlite3DebugPrintf("All WHERE-clause terms after coding level %d:\n",
+                       iLevel);
+    sqlite3WhereClausePrint(pWC);
+  }
+  if( sqlite3WhereTrace & 0x1 ){
+    sqlite3DebugPrintf("End Coding level %d:  notReady=%llx\n",
+       iLevel, (u64)pLevel->notReady);
+  }
+#endif
+  return pLevel->notReady;
+}
+
+/*
+** Generate the code for the loop that finds all non-matched terms
+** for a RIGHT JOIN.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE void sqlite3WhereRightJoinLoop(
+  WhereInfo *pWInfo,
+  int iLevel,
+  WhereLevel *pLevel
+){
+  Parse *pParse = pWInfo->pParse;
+  Vdbe *v = pParse->pVdbe;
+  WhereRightJoin *pRJ = pLevel->pRJ;
+  Expr *pSubWhere = 0;
+  WhereClause *pWC = &pWInfo->sWC;
+  WhereInfo *pSubWInfo;
+  WhereLoop *pLoop = pLevel->pWLoop;
+  SrcItem *pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
+  SrcList sFrom;
+  Bitmask mAll = 0;
+  int k;
+
+  ExplainQueryPlan((pParse, 1, "RIGHT-JOIN %s", pTabItem->pSTab->zName));
+  sqlite3VdbeNoJumpsOutsideSubrtn(v, pRJ->addrSubrtn, pRJ->endSubrtn,
+                                  pRJ->regReturn);
+  for(k=0; k<iLevel; k++){
+    int iIdxCur;
+    SrcItem *pRight;
+    assert( pWInfo->a[k].pWLoop->iTab == pWInfo->a[k].iFrom );
+    pRight = &pWInfo->pTabList->a[pWInfo->a[k].iFrom];
+    mAll |= pWInfo->a[k].pWLoop->maskSelf;
+    if( pRight->fg.viaCoroutine ){
+      Subquery *pSubq;
+      assert( pRight->fg.isSubquery && pRight->u4.pSubq!=0 );
+      pSubq = pRight->u4.pSubq;
+      assert( pSubq->pSelect!=0 && pSubq->pSelect->pEList!=0 );
+      sqlite3VdbeAddOp3(
+          v, OP_Null, 0, pSubq->regResult,
+          pSubq->regResult + pSubq->pSelect->pEList->nExpr-1
+      );
+    }
+    sqlite3VdbeAddOp1(v, OP_NullRow, pWInfo->a[k].iTabCur);
+    iIdxCur = pWInfo->a[k].iIdxCur;
+    if( iIdxCur ){
+      sqlite3VdbeAddOp1(v, OP_NullRow, iIdxCur);
+    }
+  }
+  if( (pTabItem->fg.jointype & JT_LTORJ)==0 ){
+    mAll |= pLoop->maskSelf;
+    for(k=0; k<pWC->nTerm; k++){
+      WhereTerm *pTerm = &pWC->a[k];
+      if( (pTerm->wtFlags & (TERM_VIRTUAL|TERM_SLICE))!=0
+       && pTerm->eOperator!=WO_ROWVAL
+      ){
+        break;
+      }
+      if( pTerm->prereqAll & ~mAll ) continue;
+      if( ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON) ) continue;
+      pSubWhere = sqlite3ExprAnd(pParse, pSubWhere,
+                                 sqlite3ExprDup(pParse->db, pTerm->pExpr, 0));
+    }
+  }
+  sFrom.nSrc = 1;
+  sFrom.nAlloc = 1;
+  memcpy(&sFrom.a[0], pTabItem, sizeof(SrcItem));
+  sFrom.a[0].fg.jointype = 0;
+  assert( pParse->withinRJSubrtn < 100 );
+  pParse->withinRJSubrtn++;
+  pSubWInfo = sqlite3WhereBegin(pParse, &sFrom, pSubWhere, 0, 0, 0,
+                                WHERE_RIGHT_JOIN, 0);
+  if( pSubWInfo ){
+    int iCur = pLevel->iTabCur;
+    int r = ++pParse->nMem;
+    int nPk;
+    int jmp;
+    int addrCont = sqlite3WhereContinueLabel(pSubWInfo);
+    Table *pTab = pTabItem->pSTab;
+    if( HasRowid(pTab) ){
+      sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, r);
+      nPk = 1;
+    }else{
+      int iPk;
+      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+      nPk = pPk->nKeyCol;
+      pParse->nMem += nPk - 1;
+      for(iPk=0; iPk<nPk; iPk++){
+        int iCol = pPk->aiColumn[iPk];
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+iPk);
+      }
+    }
+    jmp = sqlite3VdbeAddOp4Int(v, OP_Filter, pRJ->regBloom, 0, r, nPk);
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp4Int(v, OP_Found, pRJ->iMatch, addrCont, r, nPk);
+    VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, jmp);
+    sqlite3VdbeAddOp2(v, OP_Gosub, pRJ->regReturn, pRJ->addrSubrtn);
+    sqlite3WhereEnd(pSubWInfo);
+  }
+  sqlite3ExprDelete(pParse->db, pSubWhere);
+  ExplainQueryPlanPop(pParse);
+  assert( pParse->withinRJSubrtn>0 );
+  pParse->withinRJSubrtn--;
+}
+
+/************** End of wherecode.c *******************************************/
+/************** Begin file whereexpr.c ***************************************/
+/*
+** 2015-06-08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This module contains C code that generates VDBE code used to process
+** the WHERE clause of SQL statements.
+**
+** This file was originally part of where.c but was split out to improve
+** readability and editability.  This file contains utility routines for
+** analyzing Expr objects in the WHERE clause.
+*/
+/* #include "sqliteInt.h" */
+/* #include "whereInt.h" */
+
+/* Forward declarations */
+static void exprAnalyze(SrcList*, WhereClause*, int);
+
+/*
+** Deallocate all memory associated with a WhereOrInfo object.
+*/
+static void whereOrInfoDelete(sqlite3 *db, WhereOrInfo *p){
+  sqlite3WhereClauseClear(&p->wc);
+  sqlite3DbFree(db, p);
+}
+
+/*
+** Deallocate all memory associated with a WhereAndInfo object.
+*/
+static void whereAndInfoDelete(sqlite3 *db, WhereAndInfo *p){
+  sqlite3WhereClauseClear(&p->wc);
+  sqlite3DbFree(db, p);
+}
+
+/*
+** Add a single new WhereTerm entry to the WhereClause object pWC.
+** The new WhereTerm object is constructed from Expr p and with wtFlags.
+** The index in pWC->a[] of the new WhereTerm is returned on success.
+** 0 is returned if the new WhereTerm could not be added due to a memory
+** allocation error.  The memory allocation failure will be recorded in
+** the db->mallocFailed flag so that higher-level functions can detect it.
+**
+** This routine will increase the size of the pWC->a[] array as necessary.
+**
+** If the wtFlags argument includes TERM_DYNAMIC, then responsibility
+** for freeing the expression p is assumed by the WhereClause object pWC.
+** This is true even if this routine fails to allocate a new WhereTerm.
+**
+** WARNING:  This routine might reallocate the space used to store
+** WhereTerms.  All pointers to WhereTerms should be invalidated after
+** calling this routine.  Such pointers may be reinitialized by referencing
+** the pWC->a[] array.
+*/
+static int whereClauseInsert(WhereClause *pWC, Expr *p, u16 wtFlags){
+  WhereTerm *pTerm;
+  int idx;
+  testcase( wtFlags & TERM_VIRTUAL );
+  if( pWC->nTerm>=pWC->nSlot ){
+    WhereTerm *pOld = pWC->a;
+    sqlite3 *db = pWC->pWInfo->pParse->db;
+    pWC->a = sqlite3WhereMalloc(pWC->pWInfo, sizeof(pWC->a[0])*pWC->nSlot*2 );
+    if( pWC->a==0 ){
+      if( wtFlags & TERM_DYNAMIC ){
+        sqlite3ExprDelete(db, p);
+      }
+      pWC->a = pOld;
+      return 0;
+    }
+    memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
+    pWC->nSlot = pWC->nSlot*2;
+  }
+  pTerm = &pWC->a[idx = pWC->nTerm++];
+  if( (wtFlags & TERM_VIRTUAL)==0 ) pWC->nBase = pWC->nTerm;
+  if( p && ExprHasProperty(p, EP_Unlikely) ){
+    pTerm->truthProb = sqlite3LogEst(p->iTable) - 270;
+  }else{
+    pTerm->truthProb = 1;
+  }
+  pTerm->pExpr = sqlite3ExprSkipCollateAndLikely(p);
+  pTerm->wtFlags = wtFlags;
+  pTerm->pWC = pWC;
+  pTerm->iParent = -1;
+  memset(&pTerm->eOperator, 0,
+         sizeof(WhereTerm) - offsetof(WhereTerm,eOperator));
+  return idx;
+}
+
+/*
+** Return TRUE if the given operator is one of the operators that is
+** allowed for an indexable WHERE clause term.  The allowed operators are
+** "=", "<", ">", "<=", ">=", "IN", "IS", and "IS NULL"
+*/
+static int allowedOp(int op){
+  assert( TK_GT>TK_EQ && TK_GT<TK_GE );
+  assert( TK_LT>TK_EQ && TK_LT<TK_GE );
+  assert( TK_LE>TK_EQ && TK_LE<TK_GE );
+  assert( TK_GE==TK_EQ+4 );
+  assert( TK_IN<TK_EQ );
+  assert( TK_IS<TK_EQ );
+  assert( TK_ISNULL<TK_EQ );
+  if( op>TK_GE ) return 0;
+  if( op>=TK_EQ ) return 1;
+  return op==TK_IN || op==TK_ISNULL || op==TK_IS;
+}
+
+/*
+** Commute a comparison operator.  Expressions of the form "X op Y"
+** are converted into "Y op X".
+*/
+static u16 exprCommute(Parse *pParse, Expr *pExpr){
+  if( pExpr->pLeft->op==TK_VECTOR
+   || pExpr->pRight->op==TK_VECTOR
+   || sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft, pExpr->pRight) !=
+      sqlite3BinaryCompareCollSeq(pParse, pExpr->pRight, pExpr->pLeft)
+  ){
+    pExpr->flags ^= EP_Commuted;
+  }
+  SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
+  if( pExpr->op>=TK_GT ){
+    assert( TK_LT==TK_GT+2 );
+    assert( TK_GE==TK_LE+2 );
+    assert( TK_GT>TK_EQ );
+    assert( TK_GT<TK_LE );
+    assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
+    pExpr->op = ((pExpr->op-TK_GT)^2)+TK_GT;
+  }
+  return 0;
+}
+
+/*
+** Translate from TK_xx operator to WO_xx bitmask.
+*/
+static u16 operatorMask(int op){
+  u16 c;
+  assert( allowedOp(op) );
+  if( op>=TK_EQ ){
+    assert( (WO_EQ<<(op-TK_EQ)) < 0x7fff );
+    c = (u16)(WO_EQ<<(op-TK_EQ));
+  }else if( op==TK_IN ){
+    c = WO_IN;
+  }else if( op==TK_ISNULL ){
+    c = WO_ISNULL;
+  }else{
+    assert( op==TK_IS );
+    c = WO_IS;
+  }
+  assert( op!=TK_ISNULL || c==WO_ISNULL );
+  assert( op!=TK_IN || c==WO_IN );
+  assert( op!=TK_EQ || c==WO_EQ );
+  assert( op!=TK_LT || c==WO_LT );
+  assert( op!=TK_LE || c==WO_LE );
+  assert( op!=TK_GT || c==WO_GT );
+  assert( op!=TK_GE || c==WO_GE );
+  assert( op!=TK_IS || c==WO_IS );
+  return c;
+}
+
+
+#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
+/*
+** Check to see if the given expression is a LIKE or GLOB operator that
+** can be optimized using inequality constraints.  Return TRUE if it is
+** so and false if not.
+**
+** In order for the operator to be optimizible, the RHS must be a string
+** literal that does not begin with a wildcard.  The LHS must be a column
+** that may only be NULL, a string, or a BLOB, never a number. (This means
+** that virtual tables cannot participate in the LIKE optimization.)  The
+** collating sequence for the column on the LHS must be appropriate for
+** the operator.
+*/
+static int isLikeOrGlob(
+  Parse *pParse,    /* Parsing and code generating context */
+  Expr *pExpr,      /* Test this expression */
+  Expr **ppPrefix,  /* Pointer to TK_STRING expression with pattern prefix */
+  int *pisComplete, /* True if the only wildcard is % in the last character */
+  int *pnoCase      /* True if uppercase is equivalent to lowercase */
+){
+  const u8 *z = 0;           /* String on RHS of LIKE operator */
+  Expr *pRight, *pLeft;      /* Right and left size of LIKE operator */
+  ExprList *pList;           /* List of operands to the LIKE operator */
+  u8 c;                      /* One character in z[] */
+  int cnt;                   /* Number of non-wildcard prefix characters */
+  u8 wc[4];                  /* Wildcard characters */
+  sqlite3 *db = pParse->db;  /* Database connection */
+  sqlite3_value *pVal = 0;
+  int op;                    /* Opcode of pRight */
+  int rc;                    /* Result code to return */
+
+  if( !sqlite3IsLikeFunction(db, pExpr, pnoCase, (char*)wc) ){
+    return 0;
+  }
+#ifdef SQLITE_EBCDIC
+  if( *pnoCase ) return 0;
+#endif
+  assert( ExprUseXList(pExpr) );
+  pList = pExpr->x.pList;
+  pLeft = pList->a[1].pExpr;
+
+  pRight = sqlite3ExprSkipCollate(pList->a[0].pExpr);
+  op = pRight->op;
+  if( op==TK_VARIABLE && (db->flags & SQLITE_EnableQPSG)==0 ){
+    Vdbe *pReprepare = pParse->pReprepare;
+    int iCol = pRight->iColumn;
+    pVal = sqlite3VdbeGetBoundValue(pReprepare, iCol, SQLITE_AFF_BLOB);
+    if( pVal && sqlite3_value_type(pVal)==SQLITE_TEXT ){
+      z = sqlite3_value_text(pVal);
+    }
+    sqlite3VdbeSetVarmask(pParse->pVdbe, iCol);
+    assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER );
+  }else if( op==TK_STRING ){
+    assert( !ExprHasProperty(pRight, EP_IntValue) );
+     z = (u8*)pRight->u.zToken;
+  }
+  if( z ){
+    /* Count the number of prefix bytes prior to the first wildcard,
+    ** U+fffd character, or malformed utf-8. If the underlying database
+    ** has a UTF16LE encoding, then only consider ASCII characters.  Note that
+    ** the encoding of z[] is UTF8 - we are dealing with only UTF8 here in this
+    ** code, but the database engine itself might be processing content using a
+    ** different encoding. */
+    cnt = 0;
+    while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){
+      cnt++;
+      if( c==wc[3] && z[cnt]>0 && z[cnt]<0x80 ){
+        cnt++;
+      }else if( c>=0x80 ){
+        const u8 *z2 = z+cnt-1;
+        if( c==0xff || sqlite3Utf8Read(&z2)==0xfffd  /* bad utf-8 */
+         || ENC(db)==SQLITE_UTF16LE
+        ){
+          cnt--;
+          break;
+        }else{
+          cnt = (int)(z2-z);
+        }
+      }
+    }
+
+    /* The optimization is possible only if (1) the pattern does not begin
+    ** with a wildcard and if (2) the non-wildcard prefix does not end with
+    ** an (illegal 0xff) character, or (3) the pattern does not consist of
+    ** a single escape character. The second condition is necessary so
+    ** that we can increment the prefix key to find an upper bound for the
+    ** range search. The third is because the caller assumes that the pattern
+    ** consists of at least one character after all escapes have been
+    ** removed.  */
+    if( (cnt>1 || (cnt>0 && z[0]!=wc[3])) && ALWAYS(255!=(u8)z[cnt-1]) ){
+      Expr *pPrefix;
+
+      /* A "complete" match if the pattern ends with "*" or "%" */
+      *pisComplete = c==wc[0] && z[cnt+1]==0 && ENC(db)!=SQLITE_UTF16LE;
+
+      /* Get the pattern prefix.  Remove all escapes from the prefix. */
+      pPrefix = sqlite3Expr(db, TK_STRING, (char*)z);
+      if( pPrefix ){
+        int iFrom, iTo;
+        char *zNew;
+        assert( !ExprHasProperty(pPrefix, EP_IntValue) );
+        zNew = pPrefix->u.zToken;
+        zNew[cnt] = 0;
+        for(iFrom=iTo=0; iFrom<cnt; iFrom++){
+          if( zNew[iFrom]==wc[3] ) iFrom++;
+          zNew[iTo++] = zNew[iFrom];
+        }
+        zNew[iTo] = 0;
+        assert( iTo>0 );
+
+        /* If the LHS is not an ordinary column with TEXT affinity, then the
+        ** pattern prefix boundaries (both the start and end boundaries) must
+        ** not look like a number.  Otherwise the pattern might be treated as
+        ** a number, which will invalidate the LIKE optimization.
+        **
+        ** Getting this right has been a persistent source of bugs in the
+        ** LIKE optimization.  See, for example:
+        **    2018-09-10 https://sqlite.org/src/info/c94369cae9b561b1
+        **    2019-05-02 https://sqlite.org/src/info/b043a54c3de54b28
+        **    2019-06-10 https://sqlite.org/src/info/fd76310a5e843e07
+        **    2019-06-14 https://sqlite.org/src/info/ce8717f0885af975
+        **    2019-09-03 https://sqlite.org/src/info/0f0428096f17252a
+        */
+        if( pLeft->op!=TK_COLUMN
+         || sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT
+         || (ALWAYS( ExprUseYTab(pLeft) )
+             && ALWAYS(pLeft->y.pTab)
+             && IsVirtual(pLeft->y.pTab))  /* Might be numeric */
+        ){
+          int isNum;
+          double rDummy;
+          isNum = sqlite3AtoF(zNew, &rDummy, iTo, SQLITE_UTF8);
+          if( isNum<=0 ){
+            if( iTo==1 && zNew[0]=='-' ){
+              isNum = +1;
+            }else{
+              zNew[iTo-1]++;
+              isNum = sqlite3AtoF(zNew, &rDummy, iTo, SQLITE_UTF8);
+              zNew[iTo-1]--;
+            }
+          }
+          if( isNum>0 ){
+            sqlite3ExprDelete(db, pPrefix);
+            sqlite3ValueFree(pVal);
+            return 0;
+          }
+        }
+      }
+      *ppPrefix = pPrefix;
+
+      /* If the RHS pattern is a bound parameter, make arrangements to
+      ** reprepare the statement when that parameter is rebound */
+      if( op==TK_VARIABLE ){
+        Vdbe *v = pParse->pVdbe;
+        sqlite3VdbeSetVarmask(v, pRight->iColumn);
+        assert( !ExprHasProperty(pRight, EP_IntValue) );
+        if( *pisComplete && pRight->u.zToken[1] ){
+          /* If the rhs of the LIKE expression is a variable, and the current
+          ** value of the variable means there is no need to invoke the LIKE
+          ** function, then no OP_Variable will be added to the program.
+          ** This causes problems for the sqlite3_bind_parameter_name()
+          ** API. To work around them, add a dummy OP_Variable here.
+          */
+          int r1 = sqlite3GetTempReg(pParse);
+          sqlite3ExprCodeTarget(pParse, pRight, r1);
+          sqlite3VdbeChangeP3(v, sqlite3VdbeCurrentAddr(v)-1, 0);
+          sqlite3ReleaseTempReg(pParse, r1);
+        }
+      }
+    }else{
+      z = 0;
+    }
+  }
+
+  rc = (z!=0);
+  sqlite3ValueFree(pVal);
+  return rc;
+}
+#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Check to see if the pExpr expression is a form that needs to be passed
+** to the xBestIndex method of virtual tables.  Forms of interest include:
+**
+**          Expression                   Virtual Table Operator
+**          -----------------------      ---------------------------------
+**      1.  column MATCH expr            SQLITE_INDEX_CONSTRAINT_MATCH
+**      2.  column GLOB expr             SQLITE_INDEX_CONSTRAINT_GLOB
+**      3.  column LIKE expr             SQLITE_INDEX_CONSTRAINT_LIKE
+**      4.  column REGEXP expr           SQLITE_INDEX_CONSTRAINT_REGEXP
+**      5.  column != expr               SQLITE_INDEX_CONSTRAINT_NE
+**      6.  expr != column               SQLITE_INDEX_CONSTRAINT_NE
+**      7.  column IS NOT expr           SQLITE_INDEX_CONSTRAINT_ISNOT
+**      8.  expr IS NOT column           SQLITE_INDEX_CONSTRAINT_ISNOT
+**      9.  column IS NOT NULL           SQLITE_INDEX_CONSTRAINT_ISNOTNULL
+**
+** In every case, "column" must be a column of a virtual table.  If there
+** is a match, set *ppLeft to the "column" expression, set *ppRight to the
+** "expr" expression (even though in forms (6) and (8) the column is on the
+** right and the expression is on the left).  Also set *peOp2 to the
+** appropriate virtual table operator.  The return value is 1 or 2 if there
+** is a match.  The usual return is 1, but if the RHS is also a column
+** of virtual table in forms (5) or (7) then return 2.
+**
+** If the expression matches none of the patterns above, return 0.
+*/
+static int isAuxiliaryVtabOperator(
+  sqlite3 *db,                    /* Parsing context */
+  Expr *pExpr,                    /* Test this expression */
+  unsigned char *peOp2,           /* OUT: 0 for MATCH, or else an op2 value */
+  Expr **ppLeft,                  /* Column expression to left of MATCH/op2 */
+  Expr **ppRight                  /* Expression to left of MATCH/op2 */
+){
+  if( pExpr->op==TK_FUNCTION ){
+    static const struct Op2 {
+      const char *zOp;
+      unsigned char eOp2;
+    } aOp[] = {
+      { "match",  SQLITE_INDEX_CONSTRAINT_MATCH },
+      { "glob",   SQLITE_INDEX_CONSTRAINT_GLOB },
+      { "like",   SQLITE_INDEX_CONSTRAINT_LIKE },
+      { "regexp", SQLITE_INDEX_CONSTRAINT_REGEXP }
+    };
+    ExprList *pList;
+    Expr *pCol;                     /* Column reference */
+    int i;
+
+    assert( ExprUseXList(pExpr) );
+    pList = pExpr->x.pList;
+    if( pList==0 || pList->nExpr!=2 ){
+      return 0;
+    }
+
+    /* Built-in operators MATCH, GLOB, LIKE, and REGEXP attach to a
+    ** virtual table on their second argument, which is the same as
+    ** the left-hand side operand in their in-fix form.
+    **
+    **       vtab_column MATCH expression
+    **       MATCH(expression,vtab_column)
+    */
+    pCol = pList->a[1].pExpr;
+    assert( pCol->op!=TK_COLUMN || (ExprUseYTab(pCol) && pCol->y.pTab!=0) );
+    if( ExprIsVtab(pCol) ){
+      for(i=0; i<ArraySize(aOp); i++){
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        if( sqlite3StrICmp(pExpr->u.zToken, aOp[i].zOp)==0 ){
+          *peOp2 = aOp[i].eOp2;
+          *ppRight = pList->a[0].pExpr;
+          *ppLeft = pCol;
+          return 1;
+        }
+      }
+    }
+
+    /* We can also match against the first column of overloaded
+    ** functions where xFindFunction returns a value of at least
+    ** SQLITE_INDEX_CONSTRAINT_FUNCTION.
+    **
+    **      OVERLOADED(vtab_column,expression)
+    **
+    ** Historically, xFindFunction expected to see lower-case function
+    ** names.  But for this use case, xFindFunction is expected to deal
+    ** with function names in an arbitrary case.
+    */
+    pCol = pList->a[0].pExpr;
+    assert( pCol->op!=TK_COLUMN || ExprUseYTab(pCol) );
+    assert( pCol->op!=TK_COLUMN || (ExprUseYTab(pCol) && pCol->y.pTab!=0) );
+    if( ExprIsVtab(pCol) ){
+      sqlite3_vtab *pVtab;
+      sqlite3_module *pMod;
+      void (*xNotUsed)(sqlite3_context*,int,sqlite3_value**);
+      void *pNotUsed;
+      pVtab = sqlite3GetVTable(db, pCol->y.pTab)->pVtab;
+      assert( pVtab!=0 );
+      assert( pVtab->pModule!=0 );
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      pMod = (sqlite3_module *)pVtab->pModule;
+      if( pMod->xFindFunction!=0 ){
+        i = pMod->xFindFunction(pVtab,2, pExpr->u.zToken, &xNotUsed, &pNotUsed);
+        if( i>=SQLITE_INDEX_CONSTRAINT_FUNCTION ){
+          *peOp2 = i;
+          *ppRight = pList->a[1].pExpr;
+          *ppLeft = pCol;
+          return 1;
+        }
+      }
+    }
+  }else if( pExpr->op>=TK_EQ ){
+    /* Comparison operators are a common case.  Save a few comparisons for
+    ** that common case by terminating early. */
+    assert( TK_NE < TK_EQ );
+    assert( TK_ISNOT < TK_EQ );
+    assert( TK_NOTNULL < TK_EQ );
+    return 0;
+  }else if( pExpr->op==TK_NE || pExpr->op==TK_ISNOT || pExpr->op==TK_NOTNULL ){
+    int res = 0;
+    Expr *pLeft = pExpr->pLeft;
+    Expr *pRight = pExpr->pRight;
+    assert( pLeft->op!=TK_COLUMN || (ExprUseYTab(pLeft) && pLeft->y.pTab!=0) );
+    if( ExprIsVtab(pLeft) ){
+      res++;
+    }
+    assert( pRight==0 || pRight->op!=TK_COLUMN
+            || (ExprUseYTab(pRight) && pRight->y.pTab!=0) );
+    if( pRight && ExprIsVtab(pRight) ){
+      res++;
+      SWAP(Expr*, pLeft, pRight);
+    }
+    *ppLeft = pLeft;
+    *ppRight = pRight;
+    if( pExpr->op==TK_NE ) *peOp2 = SQLITE_INDEX_CONSTRAINT_NE;
+    if( pExpr->op==TK_ISNOT ) *peOp2 = SQLITE_INDEX_CONSTRAINT_ISNOT;
+    if( pExpr->op==TK_NOTNULL ) *peOp2 = SQLITE_INDEX_CONSTRAINT_ISNOTNULL;
+    return res;
+  }
+  return 0;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** If the pBase expression originated in the ON or USING clause of
+** a join, then transfer the appropriate markings over to derived.
+*/
+static void transferJoinMarkings(Expr *pDerived, Expr *pBase){
+  if( pDerived && ExprHasProperty(pBase, EP_OuterON|EP_InnerON) ){
+    pDerived->flags |= pBase->flags & (EP_OuterON|EP_InnerON);
+    pDerived->w.iJoin = pBase->w.iJoin;
+  }
+}
+
+/*
+** Mark term iChild as being a child of term iParent
+*/
+static void markTermAsChild(WhereClause *pWC, int iChild, int iParent){
+  pWC->a[iChild].iParent = iParent;
+  pWC->a[iChild].truthProb = pWC->a[iParent].truthProb;
+  pWC->a[iParent].nChild++;
+}
+
+/*
+** Return the N-th AND-connected subterm of pTerm.  Or if pTerm is not
+** a conjunction, then return just pTerm when N==0.  If N is exceeds
+** the number of available subterms, return NULL.
+*/
+static WhereTerm *whereNthSubterm(WhereTerm *pTerm, int N){
+  if( pTerm->eOperator!=WO_AND ){
+    return N==0 ? pTerm : 0;
+  }
+  if( N<pTerm->u.pAndInfo->wc.nTerm ){
+    return &pTerm->u.pAndInfo->wc.a[N];
+  }
+  return 0;
+}
+
+/*
+** Subterms pOne and pTwo are contained within WHERE clause pWC.  The
+** two subterms are in disjunction - they are OR-ed together.
+**
+** If these two terms are both of the form:  "A op B" with the same
+** A and B values but different operators and if the operators are
+** compatible (if one is = and the other is <, for example) then
+** add a new virtual AND term to pWC that is the combination of the
+** two.
+**
+** Some examples:
+**
+**    x<y OR x=y    -->     x<=y
+**    x=y OR x=y    -->     x=y
+**    x<=y OR x<y   -->     x<=y
+**
+** The following is NOT generated:
+**
+**    x<y OR x>y    -->     x!=y
+*/
+static void whereCombineDisjuncts(
+  SrcList *pSrc,         /* the FROM clause */
+  WhereClause *pWC,      /* The complete WHERE clause */
+  WhereTerm *pOne,       /* First disjunct */
+  WhereTerm *pTwo        /* Second disjunct */
+){
+  u16 eOp = pOne->eOperator | pTwo->eOperator;
+  sqlite3 *db;           /* Database connection (for malloc) */
+  Expr *pNew;            /* New virtual expression */
+  int op;                /* Operator for the combined expression */
+  int idxNew;            /* Index in pWC of the next virtual term */
+
+  if( (pOne->wtFlags | pTwo->wtFlags) & TERM_VNULL ) return;
+  if( (pOne->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE))==0 ) return;
+  if( (pTwo->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE))==0 ) return;
+  if( (eOp & (WO_EQ|WO_LT|WO_LE))!=eOp
+   && (eOp & (WO_EQ|WO_GT|WO_GE))!=eOp ) return;
+  assert( pOne->pExpr->pLeft!=0 && pOne->pExpr->pRight!=0 );
+  assert( pTwo->pExpr->pLeft!=0 && pTwo->pExpr->pRight!=0 );
+  if( sqlite3ExprCompare(0,pOne->pExpr->pLeft, pTwo->pExpr->pLeft, -1) ) return;
+  if( sqlite3ExprCompare(0,pOne->pExpr->pRight, pTwo->pExpr->pRight,-1) )return;
+  /* If we reach this point, it means the two subterms can be combined */
+  if( (eOp & (eOp-1))!=0 ){
+    if( eOp & (WO_LT|WO_LE) ){
+      eOp = WO_LE;
+    }else{
+      assert( eOp & (WO_GT|WO_GE) );
+      eOp = WO_GE;
+    }
+  }
+  db = pWC->pWInfo->pParse->db;
+  pNew = sqlite3ExprDup(db, pOne->pExpr, 0);
+  if( pNew==0 ) return;
+  for(op=TK_EQ; eOp!=(WO_EQ<<(op-TK_EQ)); op++){ assert( op<TK_GE ); }
+  pNew->op = op;
+  idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
+  exprAnalyze(pSrc, pWC, idxNew);
+}
+
+#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
+/*
+** Analyze a term that consists of two or more OR-connected
+** subterms.  So in:
+**
+**     ... WHERE  (a=5) AND (b=7 OR c=9 OR d=13) AND (d=13)
+**                          ^^^^^^^^^^^^^^^^^^^^
+**
+** This routine analyzes terms such as the middle term in the above example.
+** A WhereOrTerm object is computed and attached to the term under
+** analysis, regardless of the outcome of the analysis.  Hence:
+**
+**     WhereTerm.wtFlags   |=  TERM_ORINFO
+**     WhereTerm.u.pOrInfo  =  a dynamically allocated WhereOrTerm object
+**
+** The term being analyzed must have two or more of OR-connected subterms.
+** A single subterm might be a set of AND-connected sub-subterms.
+** Examples of terms under analysis:
+**
+**     (A)     t1.x=t2.y OR t1.x=t2.z OR t1.y=15 OR t1.z=t3.a+5
+**     (B)     x=expr1 OR expr2=x OR x=expr3
+**     (C)     t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
+**     (D)     x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
+**     (E)     (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
+**     (F)     x>A OR (x=A AND y>=B)
+**
+** CASE 1:
+**
+** If all subterms are of the form T.C=expr for some single column of C and
+** a single table T (as shown in example B above) then create a new virtual
+** term that is an equivalent IN expression.  In other words, if the term
+** being analyzed is:
+**
+**      x = expr1  OR  expr2 = x  OR  x = expr3
+**
+** then create a new virtual term like this:
+**
+**      x IN (expr1,expr2,expr3)
+**
+** CASE 2:
+**
+** If there are exactly two disjuncts and one side has x>A and the other side
+** has x=A (for the same x and A) then add a new virtual conjunct term to the
+** WHERE clause of the form "x>=A".  Example:
+**
+**      x>A OR (x=A AND y>B)    adds:    x>=A
+**
+** The added conjunct can sometimes be helpful in query planning.
+**
+** CASE 3:
+**
+** If all subterms are indexable by a single table T, then set
+**
+**     WhereTerm.eOperator              =  WO_OR
+**     WhereTerm.u.pOrInfo->indexable  |=  the cursor number for table T
+**
+** A subterm is "indexable" if it is of the form
+** "T.C <op> <expr>" where C is any column of table T and
+** <op> is one of "=", "<", "<=", ">", ">=", "IS NULL", or "IN".
+** A subterm is also indexable if it is an AND of two or more
+** subsubterms at least one of which is indexable.  Indexable AND
+** subterms have their eOperator set to WO_AND and they have
+** u.pAndInfo set to a dynamically allocated WhereAndTerm object.
+**
+** From another point of view, "indexable" means that the subterm could
+** potentially be used with an index if an appropriate index exists.
+** This analysis does not consider whether or not the index exists; that
+** is decided elsewhere.  This analysis only looks at whether subterms
+** appropriate for indexing exist.
+**
+** All examples A through E above satisfy case 3.  But if a term
+** also satisfies case 1 (such as B) we know that the optimizer will
+** always prefer case 1, so in that case we pretend that case 3 is not
+** satisfied.
+**
+** It might be the case that multiple tables are indexable.  For example,
+** (E) above is indexable on tables P, Q, and R.
+**
+** Terms that satisfy case 3 are candidates for lookup by using
+** separate indices to find rowids for each subterm and composing
+** the union of all rowids using a RowSet object.  This is similar
+** to "bitmap indices" in other database engines.
+**
+** OTHERWISE:
+**
+** If none of cases 1, 2, or 3 apply, then leave the eOperator set to
+** zero.  This term is not useful for search.
+*/
+static void exprAnalyzeOrTerm(
+  SrcList *pSrc,            /* the FROM clause */
+  WhereClause *pWC,         /* the complete WHERE clause */
+  int idxTerm               /* Index of the OR-term to be analyzed */
+){
+  WhereInfo *pWInfo = pWC->pWInfo;        /* WHERE clause processing context */
+  Parse *pParse = pWInfo->pParse;         /* Parser context */
+  sqlite3 *db = pParse->db;               /* Database connection */
+  WhereTerm *pTerm = &pWC->a[idxTerm];    /* The term to be analyzed */
+  Expr *pExpr = pTerm->pExpr;             /* The expression of the term */
+  int i;                                  /* Loop counters */
+  WhereClause *pOrWc;       /* Breakup of pTerm into subterms */
+  WhereTerm *pOrTerm;       /* A Sub-term within the pOrWc */
+  WhereOrInfo *pOrInfo;     /* Additional information associated with pTerm */
+  Bitmask chngToIN;         /* Tables that might satisfy case 1 */
+  Bitmask indexable;        /* Tables that are indexable, satisfying case 2 */
+
+  /*
+  ** Break the OR clause into its separate subterms.  The subterms are
+  ** stored in a WhereClause structure containing within the WhereOrInfo
+  ** object that is attached to the original OR clause term.
+  */
+  assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
+  assert( pExpr->op==TK_OR );
+  pTerm->u.pOrInfo = pOrInfo = sqlite3DbMallocZero(db, sizeof(*pOrInfo));
+  if( pOrInfo==0 ) return;
+  pTerm->wtFlags |= TERM_ORINFO;
+  pOrWc = &pOrInfo->wc;
+  memset(pOrWc->aStatic, 0, sizeof(pOrWc->aStatic));
+  sqlite3WhereClauseInit(pOrWc, pWInfo);
+  sqlite3WhereSplit(pOrWc, pExpr, TK_OR);
+  sqlite3WhereExprAnalyze(pSrc, pOrWc);
+  if( db->mallocFailed ) return;
+  assert( pOrWc->nTerm>=2 );
+
+  /*
+  ** Compute the set of tables that might satisfy cases 1 or 3.
+  */
+  indexable = ~(Bitmask)0;
+  chngToIN = ~(Bitmask)0;
+  for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
+    if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
+      WhereAndInfo *pAndInfo;
+      assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 );
+      chngToIN = 0;
+      pAndInfo = sqlite3DbMallocRawNN(db, sizeof(*pAndInfo));
+      if( pAndInfo ){
+        WhereClause *pAndWC;
+        WhereTerm *pAndTerm;
+        int j;
+        Bitmask b = 0;
+        pOrTerm->u.pAndInfo = pAndInfo;
+        pOrTerm->wtFlags |= TERM_ANDINFO;
+        pOrTerm->eOperator = WO_AND;
+        pOrTerm->leftCursor = -1;
+        pAndWC = &pAndInfo->wc;
+        memset(pAndWC->aStatic, 0, sizeof(pAndWC->aStatic));
+        sqlite3WhereClauseInit(pAndWC, pWC->pWInfo);
+        sqlite3WhereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
+        sqlite3WhereExprAnalyze(pSrc, pAndWC);
+        pAndWC->pOuter = pWC;
+        if( !db->mallocFailed ){
+          for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
+            assert( pAndTerm->pExpr );
+            if( allowedOp(pAndTerm->pExpr->op)
+             || pAndTerm->eOperator==WO_AUX
+            ){
+              b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pAndTerm->leftCursor);
+            }
+          }
+        }
+        indexable &= b;
+      }
+    }else if( pOrTerm->wtFlags & TERM_COPIED ){
+      /* Skip this term for now.  We revisit it when we process the
+      ** corresponding TERM_VIRTUAL term */
+    }else{
+      Bitmask b;
+      b = sqlite3WhereGetMask(&pWInfo->sMaskSet, pOrTerm->leftCursor);
+      if( pOrTerm->wtFlags & TERM_VIRTUAL ){
+        WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent];
+        b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pOther->leftCursor);
+      }
+      indexable &= b;
+      if( (pOrTerm->eOperator & WO_EQ)==0 ){
+        chngToIN = 0;
+      }else{
+        chngToIN &= b;
+      }
+    }
+  }
+
+  /*
+  ** Record the set of tables that satisfy case 3.  The set might be
+  ** empty.
+  */
+  pOrInfo->indexable = indexable;
+  pTerm->eOperator = WO_OR;
+  pTerm->leftCursor = -1;
+  if( indexable ){
+    pWC->hasOr = 1;
+  }
+
+  /* For a two-way OR, attempt to implementation case 2.
+  */
+  if( indexable && pOrWc->nTerm==2 ){
+    int iOne = 0;
+    WhereTerm *pOne;
+    while( (pOne = whereNthSubterm(&pOrWc->a[0],iOne++))!=0 ){
+      int iTwo = 0;
+      WhereTerm *pTwo;
+      while( (pTwo = whereNthSubterm(&pOrWc->a[1],iTwo++))!=0 ){
+        whereCombineDisjuncts(pSrc, pWC, pOne, pTwo);
+      }
+    }
+  }
+
+  /*
+  ** chngToIN holds a set of tables that *might* satisfy case 1.  But
+  ** we have to do some additional checking to see if case 1 really
+  ** is satisfied.
+  **
+  ** chngToIN will hold either 0, 1, or 2 bits.  The 0-bit case means
+  ** that there is no possibility of transforming the OR clause into an
+  ** IN operator because one or more terms in the OR clause contain
+  ** something other than == on a column in the single table.  The 1-bit
+  ** case means that every term of the OR clause is of the form
+  ** "table.column=expr" for some single table.  The one bit that is set
+  ** will correspond to the common table.  We still need to check to make
+  ** sure the same column is used on all terms.  The 2-bit case is when
+  ** the all terms are of the form "table1.column=table2.column".  It
+  ** might be possible to form an IN operator with either table1.column
+  ** or table2.column as the LHS if either is common to every term of
+  ** the OR clause.
+  **
+  ** Note that terms of the form "table.column1=table.column2" (the
+  ** same table on both sizes of the ==) cannot be optimized.
+  */
+  if( chngToIN ){
+    int okToChngToIN = 0;     /* True if the conversion to IN is valid */
+    int iColumn = -1;         /* Column index on lhs of IN operator */
+    int iCursor = -1;         /* Table cursor common to all terms */
+    int j = 0;                /* Loop counter */
+
+    /* Search for a table and column that appears on one side or the
+    ** other of the == operator in every subterm.  That table and column
+    ** will be recorded in iCursor and iColumn.  There might not be any
+    ** such table and column.  Set okToChngToIN if an appropriate table
+    ** and column is found but leave okToChngToIN false if not found.
+    */
+    for(j=0; j<2 && !okToChngToIN; j++){
+      Expr *pLeft = 0;
+      pOrTerm = pOrWc->a;
+      for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
+        assert( pOrTerm->eOperator & WO_EQ );
+        pOrTerm->wtFlags &= ~TERM_OK;
+        if( pOrTerm->leftCursor==iCursor ){
+          /* This is the 2-bit case and we are on the second iteration and
+          ** current term is from the first iteration.  So skip this term. */
+          assert( j==1 );
+          continue;
+        }
+        if( (chngToIN & sqlite3WhereGetMask(&pWInfo->sMaskSet,
+                                            pOrTerm->leftCursor))==0 ){
+          /* This term must be of the form t1.a==t2.b where t2 is in the
+          ** chngToIN set but t1 is not.  This term will be either preceded
+          ** or followed by an inverted copy (t2.b==t1.a).  Skip this term
+          ** and use its inversion. */
+          testcase( pOrTerm->wtFlags & TERM_COPIED );
+          testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
+          assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
+          continue;
+        }
+        assert( (pOrTerm->eOperator & (WO_OR|WO_AND))==0 );
+        iColumn = pOrTerm->u.x.leftColumn;
+        iCursor = pOrTerm->leftCursor;
+        pLeft = pOrTerm->pExpr->pLeft;
+        break;
+      }
+      if( i<0 ){
+        /* No candidate table+column was found.  This can only occur
+        ** on the second iteration */
+        assert( j==1 );
+        assert( IsPowerOfTwo(chngToIN) );
+        assert( chngToIN==sqlite3WhereGetMask(&pWInfo->sMaskSet, iCursor) );
+        break;
+      }
+      testcase( j==1 );
+
+      /* We have found a candidate table and column.  Check to see if that
+      ** table and column is common to every term in the OR clause */
+      okToChngToIN = 1;
+      for(; i>=0 && okToChngToIN; i--, pOrTerm++){
+        assert( pOrTerm->eOperator & WO_EQ );
+        assert( (pOrTerm->eOperator & (WO_OR|WO_AND))==0 );
+        if( pOrTerm->leftCursor!=iCursor ){
+          pOrTerm->wtFlags &= ~TERM_OK;
+        }else if( pOrTerm->u.x.leftColumn!=iColumn || (iColumn==XN_EXPR
+               && sqlite3ExprCompare(pParse, pOrTerm->pExpr->pLeft, pLeft, -1)
+        )){
+          okToChngToIN = 0;
+        }else{
+          int affLeft, affRight;
+          /* If the right-hand side is also a column, then the affinities
+          ** of both right and left sides must be such that no type
+          ** conversions are required on the right.  (Ticket #2249)
+          */
+          affRight = sqlite3ExprAffinity(pOrTerm->pExpr->pRight);
+          affLeft = sqlite3ExprAffinity(pOrTerm->pExpr->pLeft);
+          if( affRight!=0 && affRight!=affLeft ){
+            okToChngToIN = 0;
+          }else{
+            pOrTerm->wtFlags |= TERM_OK;
+          }
+        }
+      }
+    }
+
+    /* At this point, okToChngToIN is true if original pTerm satisfies
+    ** case 1.  In that case, construct a new virtual term that is
+    ** pTerm converted into an IN operator.
+    */
+    if( okToChngToIN ){
+      Expr *pDup;            /* A transient duplicate expression */
+      ExprList *pList = 0;   /* The RHS of the IN operator */
+      Expr *pLeft = 0;       /* The LHS of the IN operator */
+      Expr *pNew;            /* The complete IN operator */
+
+      for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){
+        if( (pOrTerm->wtFlags & TERM_OK)==0 ) continue;
+        assert( pOrTerm->eOperator & WO_EQ );
+        assert( (pOrTerm->eOperator & (WO_OR|WO_AND))==0 );
+        assert( pOrTerm->leftCursor==iCursor );
+        assert( pOrTerm->u.x.leftColumn==iColumn );
+        pDup = sqlite3ExprDup(db, pOrTerm->pExpr->pRight, 0);
+        pList = sqlite3ExprListAppend(pWInfo->pParse, pList, pDup);
+        pLeft = pOrTerm->pExpr->pLeft;
+      }
+      assert( pLeft!=0 );
+      pDup = sqlite3ExprDup(db, pLeft, 0);
+      pNew = sqlite3PExpr(pParse, TK_IN, pDup, 0);
+      if( pNew ){
+        int idxNew;
+        transferJoinMarkings(pNew, pExpr);
+        assert( ExprUseXList(pNew) );
+        pNew->x.pList = pList;
+        idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
+        testcase( idxNew==0 );
+        exprAnalyze(pSrc, pWC, idxNew);
+        /* pTerm = &pWC->a[idxTerm]; // would be needed if pTerm where reused */
+        markTermAsChild(pWC, idxNew, idxTerm);
+      }else{
+        sqlite3ExprListDelete(db, pList);
+      }
+    }
+  }
+}
+#endif /* !SQLITE_OMIT_OR_OPTIMIZATION && !SQLITE_OMIT_SUBQUERY */
+
+/*
+** We already know that pExpr is a binary operator where both operands are
+** column references.  This routine checks to see if pExpr is an equivalence
+** relation:
+**   1.  The SQLITE_Transitive optimization must be enabled
+**   2.  Must be either an == or an IS operator
+**   3.  Not originating in the ON clause of an OUTER JOIN
+**   4.  The affinities of A and B must be compatible
+**   5a. Both operands use the same collating sequence OR
+**   5b. The overall collating sequence is BINARY
+** If this routine returns TRUE, that means that the RHS can be substituted
+** for the LHS anyplace else in the WHERE clause where the LHS column occurs.
+** This is an optimization.  No harm comes from returning 0.  But if 1 is
+** returned when it should not be, then incorrect answers might result.
+*/
+static int termIsEquivalence(Parse *pParse, Expr *pExpr){
+  char aff1, aff2;
+  CollSeq *pColl;
+  if( !OptimizationEnabled(pParse->db, SQLITE_Transitive) ) return 0;
+  if( pExpr->op!=TK_EQ && pExpr->op!=TK_IS ) return 0;
+  if( ExprHasProperty(pExpr, EP_OuterON) ) return 0;
+  aff1 = sqlite3ExprAffinity(pExpr->pLeft);
+  aff2 = sqlite3ExprAffinity(pExpr->pRight);
+  if( aff1!=aff2
+   && (!sqlite3IsNumericAffinity(aff1) || !sqlite3IsNumericAffinity(aff2))
+  ){
+    return 0;
+  }
+  pColl = sqlite3ExprCompareCollSeq(pParse, pExpr);
+  if( sqlite3IsBinary(pColl) ) return 1;
+  return sqlite3ExprCollSeqMatch(pParse, pExpr->pLeft, pExpr->pRight);
+}
+
+/*
+** Recursively walk the expressions of a SELECT statement and generate
+** a bitmask indicating which tables are used in that expression
+** tree.
+*/
+static Bitmask exprSelectUsage(WhereMaskSet *pMaskSet, Select *pS){
+  Bitmask mask = 0;
+  while( pS ){
+    SrcList *pSrc = pS->pSrc;
+    mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pEList);
+    mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pGroupBy);
+    mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pOrderBy);
+    mask |= sqlite3WhereExprUsage(pMaskSet, pS->pWhere);
+    mask |= sqlite3WhereExprUsage(pMaskSet, pS->pHaving);
+    if( ALWAYS(pSrc!=0) ){
+      int i;
+      for(i=0; i<pSrc->nSrc; i++){
+        if( pSrc->a[i].fg.isSubquery ){
+          mask |= exprSelectUsage(pMaskSet, pSrc->a[i].u4.pSubq->pSelect);
+        }
+        if( pSrc->a[i].fg.isUsing==0 ){
+          mask |= sqlite3WhereExprUsage(pMaskSet, pSrc->a[i].u3.pOn);
+        }
+        if( pSrc->a[i].fg.isTabFunc ){
+          mask |= sqlite3WhereExprListUsage(pMaskSet, pSrc->a[i].u1.pFuncArg);
+        }
+      }
+    }
+    pS = pS->pPrior;
+  }
+  return mask;
+}
+
+/*
+** Expression pExpr is one operand of a comparison operator that might
+** be useful for indexing.  This routine checks to see if pExpr appears
+** in any index.  Return TRUE (1) if pExpr is an indexed term and return
+** FALSE (0) if not.  If TRUE is returned, also set aiCurCol[0] to the cursor
+** number of the table that is indexed and aiCurCol[1] to the column number
+** of the column that is indexed, or XN_EXPR (-2) if an expression is being
+** indexed.
+**
+** If pExpr is a TK_COLUMN column reference, then this routine always returns
+** true even if that particular column is not indexed, because the column
+** might be added to an automatic index later.
+*/
+static SQLITE_NOINLINE int exprMightBeIndexed2(
+  SrcList *pFrom,        /* The FROM clause */
+  int *aiCurCol,         /* Write the referenced table cursor and column here */
+  Expr *pExpr,           /* An operand of a comparison operator */
+  int j                  /* Start looking with the j-th pFrom entry */
+){
+  Index *pIdx;
+  int i;
+  int iCur;
+  do{
+    iCur = pFrom->a[j].iCursor;
+    for(pIdx=pFrom->a[j].pSTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      if( pIdx->aColExpr==0 ) continue;
+      for(i=0; i<pIdx->nKeyCol; i++){
+        if( pIdx->aiColumn[i]!=XN_EXPR ) continue;
+        assert( pIdx->bHasExpr );
+        if( sqlite3ExprCompareSkip(pExpr,pIdx->aColExpr->a[i].pExpr,iCur)==0
+         && !sqlite3ExprIsConstant(0,pIdx->aColExpr->a[i].pExpr)
+        ){
+          aiCurCol[0] = iCur;
+          aiCurCol[1] = XN_EXPR;
+          return 1;
+        }
+      }
+    }
+  }while( ++j < pFrom->nSrc );
+  return 0;
+}
+static int exprMightBeIndexed(
+  SrcList *pFrom,        /* The FROM clause */
+  int *aiCurCol,         /* Write the referenced table cursor & column here */
+  Expr *pExpr,           /* An operand of a comparison operator */
+  int op                 /* The specific comparison operator */
+){
+  int i;
+
+  /* If this expression is a vector to the left or right of a
+  ** inequality constraint (>, <, >= or <=), perform the processing
+  ** on the first element of the vector.  */
+  assert( TK_GT+1==TK_LE && TK_GT+2==TK_LT && TK_GT+3==TK_GE );
+  assert( TK_IS<TK_GE && TK_ISNULL<TK_GE && TK_IN<TK_GE );
+  assert( op<=TK_GE );
+  if( pExpr->op==TK_VECTOR && (op>=TK_GT && ALWAYS(op<=TK_GE)) ){
+    assert( ExprUseXList(pExpr) );
+    pExpr = pExpr->x.pList->a[0].pExpr;
+  }
+
+  if( pExpr->op==TK_COLUMN ){
+    aiCurCol[0] = pExpr->iTable;
+    aiCurCol[1] = pExpr->iColumn;
+    return 1;
+  }
+
+  for(i=0; i<pFrom->nSrc; i++){
+    Index *pIdx;
+    for(pIdx=pFrom->a[i].pSTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      if( pIdx->aColExpr ){
+        return exprMightBeIndexed2(pFrom,aiCurCol,pExpr,i);
+      }
+    }
+  }
+  return 0;
+}
+
+
+/*
+** The input to this routine is an WhereTerm structure with only the
+** "pExpr" field filled in.  The job of this routine is to analyze the
+** subexpression and populate all the other fields of the WhereTerm
+** structure.
+**
+** If the expression is of the form "<expr> <op> X" it gets commuted
+** to the standard form of "X <op> <expr>".
+**
+** If the expression is of the form "X <op> Y" where both X and Y are
+** columns, then the original expression is unchanged and a new virtual
+** term of the form "Y <op> X" is added to the WHERE clause and
+** analyzed separately.  The original term is marked with TERM_COPIED
+** and the new term is marked with TERM_DYNAMIC (because it's pExpr
+** needs to be freed with the WhereClause) and TERM_VIRTUAL (because it
+** is a commuted copy of a prior term.)  The original term has nChild=1
+** and the copy has idxParent set to the index of the original term.
+*/
+static void exprAnalyze(
+  SrcList *pSrc,            /* the FROM clause */
+  WhereClause *pWC,         /* the WHERE clause */
+  int idxTerm               /* Index of the term to be analyzed */
+){
+  WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */
+  WhereTerm *pTerm;                /* The term to be analyzed */
+  WhereMaskSet *pMaskSet;          /* Set of table index masks */
+  Expr *pExpr;                     /* The expression to be analyzed */
+  Bitmask prereqLeft;              /* Prerequisites of the pExpr->pLeft */
+  Bitmask prereqAll;               /* Prerequisites of pExpr */
+  Bitmask extraRight = 0;          /* Extra dependencies on LEFT JOIN */
+  Expr *pStr1 = 0;                 /* RHS of LIKE/GLOB operator */
+  int isComplete = 0;              /* RHS of LIKE/GLOB ends with wildcard */
+  int noCase = 0;                  /* uppercase equivalent to lowercase */
+  int op;                          /* Top-level operator.  pExpr->op */
+  Parse *pParse = pWInfo->pParse;  /* Parsing context */
+  sqlite3 *db = pParse->db;        /* Database connection */
+  unsigned char eOp2 = 0;          /* op2 value for LIKE/REGEXP/GLOB */
+  int nLeft;                       /* Number of elements on left side vector */
+
+  if( db->mallocFailed ){
+    return;
+  }
+  assert( pWC->nTerm > idxTerm );
+  pTerm = &pWC->a[idxTerm];
+  pMaskSet = &pWInfo->sMaskSet;
+  pExpr = pTerm->pExpr;
+  assert( pExpr!=0 ); /* Because malloc() has not failed */
+  assert( pExpr->op!=TK_AS && pExpr->op!=TK_COLLATE );
+  pMaskSet->bVarSelect = 0;
+  prereqLeft = sqlite3WhereExprUsage(pMaskSet, pExpr->pLeft);
+  op = pExpr->op;
+  if( op==TK_IN ){
+    assert( pExpr->pRight==0 );
+    if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
+    if( ExprUseXSelect(pExpr) ){
+      pTerm->prereqRight = exprSelectUsage(pMaskSet, pExpr->x.pSelect);
+    }else{
+      pTerm->prereqRight = sqlite3WhereExprListUsage(pMaskSet, pExpr->x.pList);
+    }
+    prereqAll = prereqLeft | pTerm->prereqRight;
+  }else{
+    pTerm->prereqRight = sqlite3WhereExprUsage(pMaskSet, pExpr->pRight);
+    if( pExpr->pLeft==0
+     || ExprHasProperty(pExpr, EP_xIsSelect|EP_IfNullRow)
+     || pExpr->x.pList!=0
+    ){
+      prereqAll = sqlite3WhereExprUsageNN(pMaskSet, pExpr);
+    }else{
+      prereqAll = prereqLeft | pTerm->prereqRight;
+    }
+  }
+  if( pMaskSet->bVarSelect ) pTerm->wtFlags |= TERM_VARSELECT;
+
+#ifdef SQLITE_DEBUG
+  if( prereqAll!=sqlite3WhereExprUsageNN(pMaskSet, pExpr) ){
+    printf("\n*** Incorrect prereqAll computed for:\n");
+    sqlite3TreeViewExpr(0,pExpr,0);
+    assert( 0 );
+  }
+#endif
+
+  if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON) ){
+    Bitmask x = sqlite3WhereGetMask(pMaskSet, pExpr->w.iJoin);
+    if( ExprHasProperty(pExpr, EP_OuterON) ){
+      prereqAll |= x;
+      extraRight = x-1;  /* ON clause terms may not be used with an index
+                         ** on left table of a LEFT JOIN.  Ticket #3015 */
+      if( (prereqAll>>1)>=x ){
+        sqlite3ErrorMsg(pParse, "ON clause references tables to its right");
+        return;
+      }
+    }else if( (prereqAll>>1)>=x ){
+      /* The ON clause of an INNER JOIN references a table to its right.
+      ** Most other SQL database engines raise an error.  But SQLite versions
+      ** 3.0 through 3.38 just put the ON clause constraint into the WHERE
+      ** clause and carried on.   Beginning with 3.39, raise an error only
+      ** if there is a RIGHT or FULL JOIN in the query.  This makes SQLite
+      ** more like other systems, and also preserves legacy. */
+      if( ALWAYS(pSrc->nSrc>0) && (pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
+        sqlite3ErrorMsg(pParse, "ON clause references tables to its right");
+        return;
+      }
+      ExprClearProperty(pExpr, EP_InnerON);
+    }
+  }
+  pTerm->prereqAll = prereqAll;
+  pTerm->leftCursor = -1;
+  pTerm->iParent = -1;
+  pTerm->eOperator = 0;
+  if( allowedOp(op) ){
+    int aiCurCol[2];
+    Expr *pLeft = sqlite3ExprSkipCollate(pExpr->pLeft);
+    Expr *pRight = sqlite3ExprSkipCollate(pExpr->pRight);
+    u16 opMask = (pTerm->prereqRight & prereqLeft)==0 ? WO_ALL : WO_EQUIV;
+
+    if( pTerm->u.x.iField>0 ){
+      assert( op==TK_IN );
+      assert( pLeft->op==TK_VECTOR );
+      assert( ExprUseXList(pLeft) );
+      pLeft = pLeft->x.pList->a[pTerm->u.x.iField-1].pExpr;
+    }
+
+    if( exprMightBeIndexed(pSrc, aiCurCol, pLeft, op) ){
+      pTerm->leftCursor = aiCurCol[0];
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      pTerm->u.x.leftColumn = aiCurCol[1];
+      pTerm->eOperator = operatorMask(op) & opMask;
+    }
+    if( op==TK_IS ) pTerm->wtFlags |= TERM_IS;
+    if( pRight
+     && exprMightBeIndexed(pSrc, aiCurCol, pRight, op)
+     && !ExprHasProperty(pRight, EP_FixedCol)
+    ){
+      WhereTerm *pNew;
+      Expr *pDup;
+      u16 eExtraOp = 0;        /* Extra bits for pNew->eOperator */
+      assert( pTerm->u.x.iField==0 );
+      if( pTerm->leftCursor>=0 ){
+        int idxNew;
+        pDup = sqlite3ExprDup(db, pExpr, 0);
+        if( db->mallocFailed ){
+          sqlite3ExprDelete(db, pDup);
+          return;
+        }
+        idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
+        if( idxNew==0 ) return;
+        pNew = &pWC->a[idxNew];
+        markTermAsChild(pWC, idxNew, idxTerm);
+        if( op==TK_IS ) pNew->wtFlags |= TERM_IS;
+        pTerm = &pWC->a[idxTerm];
+        pTerm->wtFlags |= TERM_COPIED;
+
+        if( termIsEquivalence(pParse, pDup) ){
+          pTerm->eOperator |= WO_EQUIV;
+          eExtraOp = WO_EQUIV;
+        }
+      }else{
+        pDup = pExpr;
+        pNew = pTerm;
+      }
+      pNew->wtFlags |= exprCommute(pParse, pDup);
+      pNew->leftCursor = aiCurCol[0];
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      pNew->u.x.leftColumn = aiCurCol[1];
+      testcase( (prereqLeft | extraRight) != prereqLeft );
+      pNew->prereqRight = prereqLeft | extraRight;
+      pNew->prereqAll = prereqAll;
+      pNew->eOperator = (operatorMask(pDup->op) + eExtraOp) & opMask;
+    }else
+    if( op==TK_ISNULL
+     && !ExprHasProperty(pExpr,EP_OuterON)
+     && 0==sqlite3ExprCanBeNull(pLeft)
+    ){
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      pExpr->op = TK_TRUEFALSE;  /* See tag-20230504-1 */
+      pExpr->u.zToken = "false";
+      ExprSetProperty(pExpr, EP_IsFalse);
+      pTerm->prereqAll = 0;
+      pTerm->eOperator = 0;
+    }
+  }
+
+#ifndef SQLITE_OMIT_BETWEEN_OPTIMIZATION
+  /* If a term is the BETWEEN operator, create two new virtual terms
+  ** that define the range that the BETWEEN implements.  For example:
+  **
+  **      a BETWEEN b AND c
+  **
+  ** is converted into:
+  **
+  **      (a BETWEEN b AND c) AND (a>=b) AND (a<=c)
+  **
+  ** The two new terms are added onto the end of the WhereClause object.
+  ** The new terms are "dynamic" and are children of the original BETWEEN
+  ** term.  That means that if the BETWEEN term is coded, the children are
+  ** skipped.  Or, if the children are satisfied by an index, the original
+  ** BETWEEN term is skipped.
+  */
+  else if( pExpr->op==TK_BETWEEN && pWC->op==TK_AND ){
+    ExprList *pList;
+    int i;
+    static const u8 ops[] = {TK_GE, TK_LE};
+    assert( ExprUseXList(pExpr) );
+    pList = pExpr->x.pList;
+    assert( pList!=0 );
+    assert( pList->nExpr==2 );
+    for(i=0; i<2; i++){
+      Expr *pNewExpr;
+      int idxNew;
+      pNewExpr = sqlite3PExpr(pParse, ops[i],
+                             sqlite3ExprDup(db, pExpr->pLeft, 0),
+                             sqlite3ExprDup(db, pList->a[i].pExpr, 0));
+      transferJoinMarkings(pNewExpr, pExpr);
+      idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
+      testcase( idxNew==0 );
+      exprAnalyze(pSrc, pWC, idxNew);
+      pTerm = &pWC->a[idxTerm];
+      markTermAsChild(pWC, idxNew, idxTerm);
+    }
+  }
+#endif /* SQLITE_OMIT_BETWEEN_OPTIMIZATION */
+
+#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
+  /* Analyze a term that is composed of two or more subterms connected by
+  ** an OR operator.
+  */
+  else if( pExpr->op==TK_OR ){
+    assert( pWC->op==TK_AND );
+    exprAnalyzeOrTerm(pSrc, pWC, idxTerm);
+    pTerm = &pWC->a[idxTerm];
+  }
+#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
+  /* The form "x IS NOT NULL" can sometimes be evaluated more efficiently
+  ** as "x>NULL" if x is not an INTEGER PRIMARY KEY.  So construct a
+  ** virtual term of that form.
+  **
+  ** The virtual term must be tagged with TERM_VNULL.
+  */
+  else if( pExpr->op==TK_NOTNULL ){
+    if( pExpr->pLeft->op==TK_COLUMN
+     && pExpr->pLeft->iColumn>=0
+     && !ExprHasProperty(pExpr, EP_OuterON)
+    ){
+      Expr *pNewExpr;
+      Expr *pLeft = pExpr->pLeft;
+      int idxNew;
+      WhereTerm *pNewTerm;
+
+      pNewExpr = sqlite3PExpr(pParse, TK_GT,
+                              sqlite3ExprDup(db, pLeft, 0),
+                              sqlite3ExprAlloc(db, TK_NULL, 0, 0));
+
+      idxNew = whereClauseInsert(pWC, pNewExpr,
+                                TERM_VIRTUAL|TERM_DYNAMIC|TERM_VNULL);
+      if( idxNew ){
+        pNewTerm = &pWC->a[idxNew];
+        pNewTerm->prereqRight = 0;
+        pNewTerm->leftCursor = pLeft->iTable;
+        pNewTerm->u.x.leftColumn = pLeft->iColumn;
+        pNewTerm->eOperator = WO_GT;
+        markTermAsChild(pWC, idxNew, idxTerm);
+        pTerm = &pWC->a[idxTerm];
+        pTerm->wtFlags |= TERM_COPIED;
+        pNewTerm->prereqAll = pTerm->prereqAll;
+      }
+    }
+  }
+
+
+#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
+  /* Add constraints to reduce the search space on a LIKE or GLOB
+  ** operator.
+  **
+  ** A like pattern of the form "x LIKE 'aBc%'" is changed into constraints
+  **
+  **          x>='ABC' AND x<'abd' AND x LIKE 'aBc%'
+  **
+  ** The last character of the prefix "abc" is incremented to form the
+  ** termination condition "abd".  If case is not significant (the default
+  ** for LIKE) then the lower-bound is made all uppercase and the upper-
+  ** bound is made all lowercase so that the bounds also work when comparing
+  ** BLOBs.
+  */
+  else if( pExpr->op==TK_FUNCTION
+   && pWC->op==TK_AND
+   && isLikeOrGlob(pParse, pExpr, &pStr1, &isComplete, &noCase)
+  ){
+    Expr *pLeft;       /* LHS of LIKE/GLOB operator */
+    Expr *pStr2;       /* Copy of pStr1 - RHS of LIKE/GLOB operator */
+    Expr *pNewExpr1;
+    Expr *pNewExpr2;
+    int idxNew1;
+    int idxNew2;
+    const char *zCollSeqName;     /* Name of collating sequence */
+    const u16 wtFlags = TERM_LIKEOPT | TERM_VIRTUAL | TERM_DYNAMIC;
+
+    assert( ExprUseXList(pExpr) );
+    pLeft = pExpr->x.pList->a[1].pExpr;
+    pStr2 = sqlite3ExprDup(db, pStr1, 0);
+    assert( pStr1==0 || !ExprHasProperty(pStr1, EP_IntValue) );
+    assert( pStr2==0 || !ExprHasProperty(pStr2, EP_IntValue) );
+
+
+    /* Convert the lower bound to upper-case and the upper bound to
+    ** lower-case (upper-case is less than lower-case in ASCII) so that
+    ** the range constraints also work for BLOBs
+    */
+    if( noCase && !pParse->db->mallocFailed ){
+      int i;
+      char c;
+      pTerm->wtFlags |= TERM_LIKE;
+      for(i=0; (c = pStr1->u.zToken[i])!=0; i++){
+        pStr1->u.zToken[i] = sqlite3Toupper(c);
+        pStr2->u.zToken[i] = sqlite3Tolower(c);
+      }
+    }
+
+    if( !db->mallocFailed ){
+      u8 *pC;       /* Last character before the first wildcard */
+      pC = (u8*)&pStr2->u.zToken[sqlite3Strlen30(pStr2->u.zToken)-1];
+      if( noCase ){
+        /* The point is to increment the last character before the first
+        ** wildcard.  But if we increment '@', that will push it into the
+        ** alphabetic range where case conversions will mess up the
+        ** inequality.  To avoid this, make sure to also run the full
+        ** LIKE on all candidate expressions by clearing the isComplete flag
+        */
+        if( *pC=='A'-1 ) isComplete = 0;
+        *pC = sqlite3UpperToLower[*pC];
+      }
+
+      /* Increment the value of the last utf8 character in the prefix. */
+      while( *pC==0xBF && pC>(u8*)pStr2->u.zToken ){
+        *pC = 0x80;
+        pC--;
+      }
+      assert( *pC!=0xFF );        /* isLikeOrGlob() guarantees this */
+      (*pC)++;
+    }
+    zCollSeqName = noCase ? "NOCASE" : sqlite3StrBINARY;
+    pNewExpr1 = sqlite3ExprDup(db, pLeft, 0);
+    pNewExpr1 = sqlite3PExpr(pParse, TK_GE,
+           sqlite3ExprAddCollateString(pParse,pNewExpr1,zCollSeqName),
+           pStr1);
+    transferJoinMarkings(pNewExpr1, pExpr);
+    idxNew1 = whereClauseInsert(pWC, pNewExpr1, wtFlags);
+    testcase( idxNew1==0 );
+    pNewExpr2 = sqlite3ExprDup(db, pLeft, 0);
+    pNewExpr2 = sqlite3PExpr(pParse, TK_LT,
+           sqlite3ExprAddCollateString(pParse,pNewExpr2,zCollSeqName),
+           pStr2);
+    transferJoinMarkings(pNewExpr2, pExpr);
+    idxNew2 = whereClauseInsert(pWC, pNewExpr2, wtFlags);
+    testcase( idxNew2==0 );
+    exprAnalyze(pSrc, pWC, idxNew1);
+    exprAnalyze(pSrc, pWC, idxNew2);
+    pTerm = &pWC->a[idxTerm];
+    if( isComplete ){
+      markTermAsChild(pWC, idxNew1, idxTerm);
+      markTermAsChild(pWC, idxNew2, idxTerm);
+    }
+  }
+#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
+
+  /* If there is a vector == or IS term - e.g. "(a, b) == (?, ?)" - create
+  ** new terms for each component comparison - "a = ?" and "b = ?".  The
+  ** new terms completely replace the original vector comparison, which is
+  ** no longer used.
+  **
+  ** This is only required if at least one side of the comparison operation
+  ** is not a sub-select.
+  **
+  ** tag-20220128a
+  */
+  if( (pExpr->op==TK_EQ || pExpr->op==TK_IS)
+   && (nLeft = sqlite3ExprVectorSize(pExpr->pLeft))>1
+   && sqlite3ExprVectorSize(pExpr->pRight)==nLeft
+   && ( (pExpr->pLeft->flags & EP_xIsSelect)==0
+     || (pExpr->pRight->flags & EP_xIsSelect)==0)
+   && pWC->op==TK_AND
+  ){
+    int i;
+    for(i=0; i<nLeft; i++){
+      int idxNew;
+      Expr *pNew;
+      Expr *pLeft = sqlite3ExprForVectorField(pParse, pExpr->pLeft, i, nLeft);
+      Expr *pRight = sqlite3ExprForVectorField(pParse, pExpr->pRight, i, nLeft);
+
+      pNew = sqlite3PExpr(pParse, pExpr->op, pLeft, pRight);
+      transferJoinMarkings(pNew, pExpr);
+      idxNew = whereClauseInsert(pWC, pNew, TERM_DYNAMIC|TERM_SLICE);
+      exprAnalyze(pSrc, pWC, idxNew);
+    }
+    pTerm = &pWC->a[idxTerm];
+    pTerm->wtFlags |= TERM_CODED|TERM_VIRTUAL;  /* Disable the original */
+    pTerm->eOperator = WO_ROWVAL;
+  }
+
+  /* If there is a vector IN term - e.g. "(a, b) IN (SELECT ...)" - create
+  ** a virtual term for each vector component. The expression object
+  ** used by each such virtual term is pExpr (the full vector IN(...)
+  ** expression). The WhereTerm.u.x.iField variable identifies the index within
+  ** the vector on the LHS that the virtual term represents.
+  **
+  ** This only works if the RHS is a simple SELECT (not a compound) that does
+  ** not use window functions.
+  */
+  else if( pExpr->op==TK_IN
+   && pTerm->u.x.iField==0
+   && pExpr->pLeft->op==TK_VECTOR
+   && ALWAYS( ExprUseXSelect(pExpr) )
+   && (pExpr->x.pSelect->pPrior==0 || (pExpr->x.pSelect->selFlags & SF_Values))
+#ifndef SQLITE_OMIT_WINDOWFUNC
+   && pExpr->x.pSelect->pWin==0
+#endif
+   && pWC->op==TK_AND
+  ){
+    int i;
+    for(i=0; i<sqlite3ExprVectorSize(pExpr->pLeft); i++){
+      int idxNew;
+      idxNew = whereClauseInsert(pWC, pExpr, TERM_VIRTUAL|TERM_SLICE);
+      pWC->a[idxNew].u.x.iField = i+1;
+      exprAnalyze(pSrc, pWC, idxNew);
+      markTermAsChild(pWC, idxNew, idxTerm);
+    }
+  }
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  /* Add a WO_AUX auxiliary term to the constraint set if the
+  ** current expression is of the form "column OP expr" where OP
+  ** is an operator that gets passed into virtual tables but which is
+  ** not normally optimized for ordinary tables.  In other words, OP
+  ** is one of MATCH, LIKE, GLOB, REGEXP, !=, IS, IS NOT, or NOT NULL.
+  ** This information is used by the xBestIndex methods of
+  ** virtual tables.  The native query optimizer does not attempt
+  ** to do anything with MATCH functions.
+  */
+  else if( pWC->op==TK_AND ){
+    Expr *pRight = 0, *pLeft = 0;
+    int res = isAuxiliaryVtabOperator(db, pExpr, &eOp2, &pLeft, &pRight);
+    while( res-- > 0 ){
+      int idxNew;
+      WhereTerm *pNewTerm;
+      Bitmask prereqColumn, prereqExpr;
+
+      prereqExpr = sqlite3WhereExprUsage(pMaskSet, pRight);
+      prereqColumn = sqlite3WhereExprUsage(pMaskSet, pLeft);
+      if( (prereqExpr & prereqColumn)==0 ){
+        Expr *pNewExpr;
+        pNewExpr = sqlite3PExpr(pParse, TK_MATCH,
+            0, sqlite3ExprDup(db, pRight, 0));
+        if( ExprHasProperty(pExpr, EP_OuterON) && pNewExpr ){
+          ExprSetProperty(pNewExpr, EP_OuterON);
+          pNewExpr->w.iJoin = pExpr->w.iJoin;
+        }
+        idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
+        testcase( idxNew==0 );
+        pNewTerm = &pWC->a[idxNew];
+        pNewTerm->prereqRight = prereqExpr;
+        pNewTerm->leftCursor = pLeft->iTable;
+        pNewTerm->u.x.leftColumn = pLeft->iColumn;
+        pNewTerm->eOperator = WO_AUX;
+        pNewTerm->eMatchOp = eOp2;
+        markTermAsChild(pWC, idxNew, idxTerm);
+        pTerm = &pWC->a[idxTerm];
+        pTerm->wtFlags |= TERM_COPIED;
+        pNewTerm->prereqAll = pTerm->prereqAll;
+      }
+      SWAP(Expr*, pLeft, pRight);
+    }
+  }
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+  /* Prevent ON clause terms of a LEFT JOIN from being used to drive
+  ** an index for tables to the left of the join.
+  */
+  testcase( pTerm!=&pWC->a[idxTerm] );
+  pTerm = &pWC->a[idxTerm];
+  pTerm->prereqRight |= extraRight;
+}
+
+/***************************************************************************
+** Routines with file scope above.  Interface to the rest of the where.c
+** subsystem follows.
+***************************************************************************/
+
+/*
+** This routine identifies subexpressions in the WHERE clause where
+** each subexpression is separated by the AND operator or some other
+** operator specified in the op parameter.  The WhereClause structure
+** is filled with pointers to subexpressions.  For example:
+**
+**    WHERE  a=='hello' AND coalesce(b,11)<10 AND (c+12!=d OR c==22)
+**           \________/     \_______________/     \________________/
+**            slot[0]            slot[1]               slot[2]
+**
+** The original WHERE clause in pExpr is unaltered.  All this routine
+** does is make slot[] entries point to substructure within pExpr.
+**
+** In the previous sentence and in the diagram, "slot[]" refers to
+** the WhereClause.a[] array.  The slot[] array grows as needed to contain
+** all terms of the WHERE clause.
+*/
+SQLITE_PRIVATE void sqlite3WhereSplit(WhereClause *pWC, Expr *pExpr, u8 op){
+  Expr *pE2 = sqlite3ExprSkipCollateAndLikely(pExpr);
+  pWC->op = op;
+  assert( pE2!=0 || pExpr==0 );
+  if( pE2==0 ) return;
+  if( pE2->op!=op ){
+    whereClauseInsert(pWC, pExpr, 0);
+  }else{
+    sqlite3WhereSplit(pWC, pE2->pLeft, op);
+    sqlite3WhereSplit(pWC, pE2->pRight, op);
+  }
+}
+
+/*
+** Add either a LIMIT (if eMatchOp==SQLITE_INDEX_CONSTRAINT_LIMIT) or
+** OFFSET (if eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET) term to the
+** where-clause passed as the first argument. The value for the term
+** is found in register iReg.
+**
+** In the common case where the value is a simple integer
+** (example: "LIMIT 5 OFFSET 10") then the expression codes as a
+** TK_INTEGER so that it will be available to sqlite3_vtab_rhs_value().
+** If not, then it codes as a TK_REGISTER expression.
+*/
+static void whereAddLimitExpr(
+  WhereClause *pWC,   /* Add the constraint to this WHERE clause */
+  int iReg,           /* Register that will hold value of the limit/offset */
+  Expr *pExpr,        /* Expression that defines the limit/offset */
+  int iCsr,           /* Cursor to which the constraint applies */
+  int eMatchOp        /* SQLITE_INDEX_CONSTRAINT_LIMIT or _OFFSET */
+){
+  Parse *pParse = pWC->pWInfo->pParse;
+  sqlite3 *db = pParse->db;
+  Expr *pNew;
+  int iVal = 0;
+
+  if( sqlite3ExprIsInteger(pExpr, &iVal, pParse) && iVal>=0 ){
+    Expr *pVal = sqlite3Expr(db, TK_INTEGER, 0);
+    if( pVal==0 ) return;
+    ExprSetProperty(pVal, EP_IntValue);
+    pVal->u.iValue = iVal;
+    pNew = sqlite3PExpr(pParse, TK_MATCH, 0, pVal);
+  }else{
+    Expr *pVal = sqlite3Expr(db, TK_REGISTER, 0);
+    if( pVal==0 ) return;
+    pVal->iTable = iReg;
+    pNew = sqlite3PExpr(pParse, TK_MATCH, 0, pVal);
+  }
+  if( pNew ){
+    WhereTerm *pTerm;
+    int idx;
+    idx = whereClauseInsert(pWC, pNew, TERM_DYNAMIC|TERM_VIRTUAL);
+    pTerm = &pWC->a[idx];
+    pTerm->leftCursor = iCsr;
+    pTerm->eOperator = WO_AUX;
+    pTerm->eMatchOp = eMatchOp;
+  }
+}
+
+/*
+** Possibly add terms corresponding to the LIMIT and OFFSET clauses of the
+** SELECT statement passed as the second argument. These terms are only
+** added if:
+**
+**   1. The SELECT statement has a LIMIT clause, and
+**   2. The SELECT statement is not an aggregate or DISTINCT query, and
+**   3. The SELECT statement has exactly one object in its from clause, and
+**      that object is a virtual table, and
+**   4. There are no terms in the WHERE clause that will not be passed
+**      to the virtual table xBestIndex method.
+**   5. The ORDER BY clause, if any, will be made available to the xBestIndex
+**      method.
+**
+** LIMIT and OFFSET terms are ignored by most of the planner code. They
+** exist only so that they may be passed to the xBestIndex method of the
+** single virtual table in the FROM clause of the SELECT.
+*/
+SQLITE_PRIVATE void SQLITE_NOINLINE sqlite3WhereAddLimit(WhereClause *pWC, Select *p){
+  assert( p!=0 && p->pLimit!=0 );                 /* 1 -- checked by caller */
+  if( p->pGroupBy==0
+   && (p->selFlags & (SF_Distinct|SF_Aggregate))==0             /* 2 */
+   && (p->pSrc->nSrc==1 && IsVirtual(p->pSrc->a[0].pSTab))      /* 3 */
+  ){
+    ExprList *pOrderBy = p->pOrderBy;
+    int iCsr = p->pSrc->a[0].iCursor;
+    int ii;
+
+    /* Check condition (4). Return early if it is not met. */
+    for(ii=0; ii<pWC->nTerm; ii++){
+      if( pWC->a[ii].wtFlags & TERM_CODED ){
+        /* This term is a vector operation that has been decomposed into
+        ** other, subsequent terms.  It can be ignored. See tag-20220128a */
+        assert( pWC->a[ii].wtFlags & TERM_VIRTUAL );
+        assert( pWC->a[ii].eOperator==WO_ROWVAL );
+        continue;
+      }
+      if( pWC->a[ii].nChild ){
+        /* If this term has child terms, then they are also part of the
+        ** pWC->a[] array. So this term can be ignored, as a LIMIT clause
+        ** will only be added if each of the child terms passes the
+        ** (leftCursor==iCsr) test below.  */
+        continue;
+      }
+      if( pWC->a[ii].leftCursor!=iCsr ) return;
+      if( pWC->a[ii].prereqRight!=0 ) return;
+    }
+
+    /* Check condition (5). Return early if it is not met. */
+    if( pOrderBy ){
+      for(ii=0; ii<pOrderBy->nExpr; ii++){
+        Expr *pExpr = pOrderBy->a[ii].pExpr;
+        if( pExpr->op!=TK_COLUMN ) return;
+        if( pExpr->iTable!=iCsr ) return;
+        if( pOrderBy->a[ii].fg.sortFlags & KEYINFO_ORDER_BIGNULL ) return;
+      }
+    }
+
+    /* All conditions are met. Add the terms to the where-clause object. */
+    assert( p->pLimit->op==TK_LIMIT );
+    if( p->iOffset!=0 && (p->selFlags & SF_Compound)==0 ){
+      whereAddLimitExpr(pWC, p->iOffset, p->pLimit->pRight,
+                        iCsr, SQLITE_INDEX_CONSTRAINT_OFFSET);
+    }
+    if( p->iOffset==0 || (p->selFlags & SF_Compound)==0 ){
+      whereAddLimitExpr(pWC, p->iLimit, p->pLimit->pLeft,
+                        iCsr, SQLITE_INDEX_CONSTRAINT_LIMIT);
+    }
+  }
+}
+
+/*
+** Initialize a preallocated WhereClause structure.
+*/
+SQLITE_PRIVATE void sqlite3WhereClauseInit(
+  WhereClause *pWC,        /* The WhereClause to be initialized */
+  WhereInfo *pWInfo        /* The WHERE processing context */
+){
+  pWC->pWInfo = pWInfo;
+  pWC->hasOr = 0;
+  pWC->pOuter = 0;
+  pWC->nTerm = 0;
+  pWC->nBase = 0;
+  pWC->nSlot = ArraySize(pWC->aStatic);
+  pWC->a = pWC->aStatic;
+}
+
+/*
+** Deallocate a WhereClause structure.  The WhereClause structure
+** itself is not freed.  This routine is the inverse of
+** sqlite3WhereClauseInit().
+*/
+SQLITE_PRIVATE void sqlite3WhereClauseClear(WhereClause *pWC){
+  sqlite3 *db = pWC->pWInfo->pParse->db;
+  assert( pWC->nTerm>=pWC->nBase );
+  if( pWC->nTerm>0 ){
+    WhereTerm *a = pWC->a;
+    WhereTerm *aLast = &pWC->a[pWC->nTerm-1];
+#ifdef SQLITE_DEBUG
+    int i;
+    /* Verify that every term past pWC->nBase is virtual */
+    for(i=pWC->nBase; i<pWC->nTerm; i++){
+      assert( (pWC->a[i].wtFlags & TERM_VIRTUAL)!=0 );
+    }
+#endif
+    while(1){
+      assert( a->eMatchOp==0 || a->eOperator==WO_AUX );
+      if( a->wtFlags & TERM_DYNAMIC ){
+        sqlite3ExprDelete(db, a->pExpr);
+      }
+      if( a->wtFlags & (TERM_ORINFO|TERM_ANDINFO) ){
+        if( a->wtFlags & TERM_ORINFO ){
+          assert( (a->wtFlags & TERM_ANDINFO)==0 );
+          whereOrInfoDelete(db, a->u.pOrInfo);
+        }else{
+          assert( (a->wtFlags & TERM_ANDINFO)!=0 );
+          whereAndInfoDelete(db, a->u.pAndInfo);
+        }
+      }
+      if( a==aLast ) break;
+      a++;
+    }
+  }
+}
+
+
+/*
+** These routines walk (recursively) an expression tree and generate
+** a bitmask indicating which tables are used in that expression
+** tree.
+**
+** sqlite3WhereExprUsage(MaskSet, Expr) ->
+**
+**       Return a Bitmask of all tables referenced by Expr.  Expr can be
+**       be NULL, in which case 0 is returned.
+**
+** sqlite3WhereExprUsageNN(MaskSet, Expr) ->
+**
+**       Same as sqlite3WhereExprUsage() except that Expr must not be
+**       NULL.  The "NN" suffix on the name stands for "Not Null".
+**
+** sqlite3WhereExprListUsage(MaskSet, ExprList) ->
+**
+**       Return a Bitmask of all tables referenced by every expression
+**       in the expression list ExprList.  ExprList can be NULL, in which
+**       case 0 is returned.
+**
+** sqlite3WhereExprUsageFull(MaskSet, ExprList) ->
+**
+**       Internal use only.  Called only by sqlite3WhereExprUsageNN() for
+**       complex expressions that require pushing register values onto
+**       the stack.  Many calls to sqlite3WhereExprUsageNN() do not need
+**       the more complex analysis done by this routine.  Hence, the
+**       computations done by this routine are broken out into a separate
+**       "no-inline" function to avoid the stack push overhead in the
+**       common case where it is not needed.
+*/
+static SQLITE_NOINLINE Bitmask sqlite3WhereExprUsageFull(
+  WhereMaskSet *pMaskSet,
+  Expr *p
+){
+  Bitmask mask;
+  mask = (p->op==TK_IF_NULL_ROW) ? sqlite3WhereGetMask(pMaskSet, p->iTable) : 0;
+  if( p->pLeft ) mask |= sqlite3WhereExprUsageNN(pMaskSet, p->pLeft);
+  if( p->pRight ){
+    mask |= sqlite3WhereExprUsageNN(pMaskSet, p->pRight);
+    assert( p->x.pList==0 );
+  }else if( ExprUseXSelect(p) ){
+    if( ExprHasProperty(p, EP_VarSelect) ) pMaskSet->bVarSelect = 1;
+    mask |= exprSelectUsage(pMaskSet, p->x.pSelect);
+  }else if( p->x.pList ){
+    mask |= sqlite3WhereExprListUsage(pMaskSet, p->x.pList);
+  }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( (p->op==TK_FUNCTION || p->op==TK_AGG_FUNCTION) && ExprUseYWin(p) ){
+    assert( p->y.pWin!=0 );
+    mask |= sqlite3WhereExprListUsage(pMaskSet, p->y.pWin->pPartition);
+    mask |= sqlite3WhereExprListUsage(pMaskSet, p->y.pWin->pOrderBy);
+    mask |= sqlite3WhereExprUsage(pMaskSet, p->y.pWin->pFilter);
+  }
+#endif
+  return mask;
+}
+SQLITE_PRIVATE Bitmask sqlite3WhereExprUsageNN(WhereMaskSet *pMaskSet, Expr *p){
+  if( p->op==TK_COLUMN && !ExprHasProperty(p, EP_FixedCol) ){
+    return sqlite3WhereGetMask(pMaskSet, p->iTable);
+  }else if( ExprHasProperty(p, EP_TokenOnly|EP_Leaf) ){
+    assert( p->op!=TK_IF_NULL_ROW );
+    return 0;
+  }
+  return sqlite3WhereExprUsageFull(pMaskSet, p);
+}
+SQLITE_PRIVATE Bitmask sqlite3WhereExprUsage(WhereMaskSet *pMaskSet, Expr *p){
+  return p ? sqlite3WhereExprUsageNN(pMaskSet,p) : 0;
+}
+SQLITE_PRIVATE Bitmask sqlite3WhereExprListUsage(WhereMaskSet *pMaskSet, ExprList *pList){
+  int i;
+  Bitmask mask = 0;
+  if( pList ){
+    for(i=0; i<pList->nExpr; i++){
+      mask |= sqlite3WhereExprUsage(pMaskSet, pList->a[i].pExpr);
+    }
+  }
+  return mask;
+}
+
+
+/*
+** Call exprAnalyze on all terms in a WHERE clause.
+**
+** Note that exprAnalyze() might add new virtual terms onto the
+** end of the WHERE clause.  We do not want to analyze these new
+** virtual terms, so start analyzing at the end and work forward
+** so that the added virtual terms are never processed.
+*/
+SQLITE_PRIVATE void sqlite3WhereExprAnalyze(
+  SrcList *pTabList,       /* the FROM clause */
+  WhereClause *pWC         /* the WHERE clause to be analyzed */
+){
+  int i;
+  for(i=pWC->nTerm-1; i>=0; i--){
+    exprAnalyze(pTabList, pWC, i);
+  }
+}
+
+/*
+** For table-valued-functions, transform the function arguments into
+** new WHERE clause terms.
+**
+** Each function argument translates into an equality constraint against
+** a HIDDEN column in the table.
+*/
+SQLITE_PRIVATE void sqlite3WhereTabFuncArgs(
+  Parse *pParse,                    /* Parsing context */
+  SrcItem *pItem,                   /* The FROM clause term to process */
+  WhereClause *pWC                  /* Xfer function arguments to here */
+){
+  Table *pTab;
+  int j, k;
+  ExprList *pArgs;
+  Expr *pColRef;
+  Expr *pTerm;
+  if( pItem->fg.isTabFunc==0 ) return;
+  pTab = pItem->pSTab;
+  assert( pTab!=0 );
+  pArgs = pItem->u1.pFuncArg;
+  if( pArgs==0 ) return;
+  for(j=k=0; j<pArgs->nExpr; j++){
+    Expr *pRhs;
+    u32 joinType;
+    while( k<pTab->nCol && (pTab->aCol[k].colFlags & COLFLAG_HIDDEN)==0 ){k++;}
+    if( k>=pTab->nCol ){
+      sqlite3ErrorMsg(pParse, "too many arguments on %s() - max %d",
+                      pTab->zName, j);
+      return;
+    }
+    pColRef = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0);
+    if( pColRef==0 ) return;
+    pColRef->iTable = pItem->iCursor;
+    pColRef->iColumn = k++;
+    assert( ExprUseYTab(pColRef) );
+    pColRef->y.pTab = pTab;
+    pItem->colUsed |= sqlite3ExprColUsed(pColRef);
+    pRhs = sqlite3PExpr(pParse, TK_UPLUS,
+        sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0), 0);
+    pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef, pRhs);
+    if( pItem->fg.jointype & (JT_LEFT|JT_RIGHT) ){
+      testcase( pItem->fg.jointype & JT_LEFT );  /* testtag-20230227a */
+      testcase( pItem->fg.jointype & JT_RIGHT ); /* testtag-20230227b */
+      joinType = EP_OuterON;
+    }else{
+      testcase( pItem->fg.jointype & JT_LTORJ ); /* testtag-20230227c */
+      joinType = EP_InnerON;
+    }
+    sqlite3SetJoinExpr(pTerm, pItem->iCursor, joinType);
+    whereClauseInsert(pWC, pTerm, TERM_DYNAMIC);
+  }
+}
+
+/************** End of whereexpr.c *******************************************/
+/************** Begin file where.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This module contains C code that generates VDBE code used to process
+** the WHERE clause of SQL statements.  This module is responsible for
+** generating the code that loops through a table looking for applicable
+** rows.  Indices are selected and used to speed the search when doing
+** so is applicable.  Because this module is responsible for selecting
+** indices, you might also think of this module as the "query optimizer".
+*/
+/* #include "sqliteInt.h" */
+/* #include "whereInt.h" */
+
+/*
+** Extra information appended to the end of sqlite3_index_info but not
+** visible to the xBestIndex function, at least not directly.  The
+** sqlite3_vtab_collation() interface knows how to reach it, however.
+**
+** This object is not an API and can be changed from one release to the
+** next.  As long as allocateIndexInfo() and sqlite3_vtab_collation()
+** agree on the structure, all will be well.
+*/
+typedef struct HiddenIndexInfo HiddenIndexInfo;
+struct HiddenIndexInfo {
+  WhereClause *pWC;        /* The Where clause being analyzed */
+  Parse *pParse;           /* The parsing context */
+  int eDistinct;           /* Value to return from sqlite3_vtab_distinct() */
+  u32 mIn;                 /* Mask of terms that are <col> IN (...) */
+  u32 mHandleIn;           /* Terms that vtab will handle as <col> IN (...) */
+  sqlite3_value *aRhs[1];  /* RHS values for constraints. MUST BE LAST
+                           ** because extra space is allocated to hold up
+                           ** to nTerm such values */
+};
+
+/* Forward declaration of methods */
+static int whereLoopResize(sqlite3*, WhereLoop*, int);
+
+/*
+** Return the estimated number of output rows from a WHERE clause
+*/
+SQLITE_PRIVATE LogEst sqlite3WhereOutputRowCount(WhereInfo *pWInfo){
+  return pWInfo->nRowOut;
+}
+
+/*
+** Return one of the WHERE_DISTINCT_xxxxx values to indicate how this
+** WHERE clause returns outputs for DISTINCT processing.
+*/
+SQLITE_PRIVATE int sqlite3WhereIsDistinct(WhereInfo *pWInfo){
+  return pWInfo->eDistinct;
+}
+
+/*
+** Return the number of ORDER BY terms that are satisfied by the
+** WHERE clause.  A return of 0 means that the output must be
+** completely sorted.  A return equal to the number of ORDER BY
+** terms means that no sorting is needed at all.  A return that
+** is positive but less than the number of ORDER BY terms means that
+** block sorting is required.
+*/
+SQLITE_PRIVATE int sqlite3WhereIsOrdered(WhereInfo *pWInfo){
+  return pWInfo->nOBSat<0 ? 0 : pWInfo->nOBSat;
+}
+
+/*
+** In the ORDER BY LIMIT optimization, if the inner-most loop is known
+** to emit rows in increasing order, and if the last row emitted by the
+** inner-most loop did not fit within the sorter, then we can skip all
+** subsequent rows for the current iteration of the inner loop (because they
+** will not fit in the sorter either) and continue with the second inner
+** loop - the loop immediately outside the inner-most.
+**
+** When a row does not fit in the sorter (because the sorter already
+** holds LIMIT+OFFSET rows that are smaller), then a jump is made to the
+** label returned by this function.
+**
+** If the ORDER BY LIMIT optimization applies, the jump destination should
+** be the continuation for the second-inner-most loop.  If the ORDER BY
+** LIMIT optimization does not apply, then the jump destination should
+** be the continuation for the inner-most loop.
+**
+** It is always safe for this routine to return the continuation of the
+** inner-most loop, in the sense that a correct answer will result.
+** Returning the continuation the second inner loop is an optimization
+** that might make the code run a little faster, but should not change
+** the final answer.
+*/
+SQLITE_PRIVATE int sqlite3WhereOrderByLimitOptLabel(WhereInfo *pWInfo){
+  WhereLevel *pInner;
+  if( !pWInfo->bOrderedInnerLoop ){
+    /* The ORDER BY LIMIT optimization does not apply.  Jump to the
+    ** continuation of the inner-most loop. */
+    return pWInfo->iContinue;
+  }
+  pInner = &pWInfo->a[pWInfo->nLevel-1];
+  assert( pInner->addrNxt!=0 );
+  return pInner->pRJ ? pWInfo->iContinue : pInner->addrNxt;
+}
+
+/*
+** While generating code for the min/max optimization, after handling
+** the aggregate-step call to min() or max(), check to see if any
+** additional looping is required.  If the output order is such that
+** we are certain that the correct answer has already been found, then
+** code an OP_Goto to by pass subsequent processing.
+**
+** Any extra OP_Goto that is coded here is an optimization.  The
+** correct answer should be obtained regardless.  This OP_Goto just
+** makes the answer appear faster.
+*/
+SQLITE_PRIVATE void sqlite3WhereMinMaxOptEarlyOut(Vdbe *v, WhereInfo *pWInfo){
+  WhereLevel *pInner;
+  int i;
+  if( !pWInfo->bOrderedInnerLoop ) return;
+  if( pWInfo->nOBSat==0 ) return;
+  for(i=pWInfo->nLevel-1; i>=0; i--){
+    pInner = &pWInfo->a[i];
+    if( (pInner->pWLoop->wsFlags & WHERE_COLUMN_IN)!=0 ){
+      sqlite3VdbeGoto(v, pInner->addrNxt);
+      return;
+    }
+  }
+  sqlite3VdbeGoto(v, pWInfo->iBreak);
+}
+
+/*
+** Return the VDBE address or label to jump to in order to continue
+** immediately with the next row of a WHERE clause.
+*/
+SQLITE_PRIVATE int sqlite3WhereContinueLabel(WhereInfo *pWInfo){
+  assert( pWInfo->iContinue!=0 );
+  return pWInfo->iContinue;
+}
+
+/*
+** Return the VDBE address or label to jump to in order to break
+** out of a WHERE loop.
+*/
+SQLITE_PRIVATE int sqlite3WhereBreakLabel(WhereInfo *pWInfo){
+  return pWInfo->iBreak;
+}
+
+/*
+** Return ONEPASS_OFF (0) if an UPDATE or DELETE statement is unable to
+** operate directly on the rowids returned by a WHERE clause.  Return
+** ONEPASS_SINGLE (1) if the statement can operation directly because only
+** a single row is to be changed.  Return ONEPASS_MULTI (2) if the one-pass
+** optimization can be used on multiple
+**
+** If the ONEPASS optimization is used (if this routine returns true)
+** then also write the indices of open cursors used by ONEPASS
+** into aiCur[0] and aiCur[1].  iaCur[0] gets the cursor of the data
+** table and iaCur[1] gets the cursor used by an auxiliary index.
+** Either value may be -1, indicating that cursor is not used.
+** Any cursors returned will have been opened for writing.
+**
+** aiCur[0] and aiCur[1] both get -1 if the where-clause logic is
+** unable to use the ONEPASS optimization.
+*/
+SQLITE_PRIVATE int sqlite3WhereOkOnePass(WhereInfo *pWInfo, int *aiCur){
+  memcpy(aiCur, pWInfo->aiCurOnePass, sizeof(int)*2);
+#ifdef WHERETRACE_ENABLED
+  if( sqlite3WhereTrace && pWInfo->eOnePass!=ONEPASS_OFF ){
+    sqlite3DebugPrintf("%s cursors: %d %d\n",
+         pWInfo->eOnePass==ONEPASS_SINGLE ? "ONEPASS_SINGLE" : "ONEPASS_MULTI",
+         aiCur[0], aiCur[1]);
+  }
+#endif
+  return pWInfo->eOnePass;
+}
+
+/*
+** Return TRUE if the WHERE loop uses the OP_DeferredSeek opcode to move
+** the data cursor to the row selected by the index cursor.
+*/
+SQLITE_PRIVATE int sqlite3WhereUsesDeferredSeek(WhereInfo *pWInfo){
+  return pWInfo->bDeferredSeek;
+}
+
+/*
+** Move the content of pSrc into pDest
+*/
+static void whereOrMove(WhereOrSet *pDest, WhereOrSet *pSrc){
+  pDest->n = pSrc->n;
+  memcpy(pDest->a, pSrc->a, pDest->n*sizeof(pDest->a[0]));
+}
+
+/*
+** Try to insert a new prerequisite/cost entry into the WhereOrSet pSet.
+**
+** The new entry might overwrite an existing entry, or it might be
+** appended, or it might be discarded.  Do whatever is the right thing
+** so that pSet keeps the N_OR_COST best entries seen so far.
+*/
+static int whereOrInsert(
+  WhereOrSet *pSet,      /* The WhereOrSet to be updated */
+  Bitmask prereq,        /* Prerequisites of the new entry */
+  LogEst rRun,           /* Run-cost of the new entry */
+  LogEst nOut            /* Number of outputs for the new entry */
+){
+  u16 i;
+  WhereOrCost *p;
+  for(i=pSet->n, p=pSet->a; i>0; i--, p++){
+    if( rRun<=p->rRun && (prereq & p->prereq)==prereq ){
+      goto whereOrInsert_done;
+    }
+    if( p->rRun<=rRun && (p->prereq & prereq)==p->prereq ){
+      return 0;
+    }
+  }
+  if( pSet->n<N_OR_COST ){
+    p = &pSet->a[pSet->n++];
+    p->nOut = nOut;
+  }else{
+    p = pSet->a;
+    for(i=1; i<pSet->n; i++){
+      if( p->rRun>pSet->a[i].rRun ) p = pSet->a + i;
+    }
+    if( p->rRun<=rRun ) return 0;
+  }
+whereOrInsert_done:
+  p->prereq = prereq;
+  p->rRun = rRun;
+  if( p->nOut>nOut ) p->nOut = nOut;
+  return 1;
+}
+
+/*
+** Return the bitmask for the given cursor number.  Return 0 if
+** iCursor is not in the set.
+*/
+SQLITE_PRIVATE Bitmask sqlite3WhereGetMask(WhereMaskSet *pMaskSet, int iCursor){
+  int i;
+  assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 );
+  assert( pMaskSet->n>0 || pMaskSet->ix[0]<0 );
+  assert( iCursor>=-1 );
+  if( pMaskSet->ix[0]==iCursor ){
+    return 1;
+  }
+  for(i=1; i<pMaskSet->n; i++){
+    if( pMaskSet->ix[i]==iCursor ){
+      return MASKBIT(i);
+    }
+  }
+  return 0;
+}
+
+/* Allocate memory that is automatically freed when pWInfo is freed.
+*/
+SQLITE_PRIVATE void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte){
+  WhereMemBlock *pBlock;
+  pBlock = sqlite3DbMallocRawNN(pWInfo->pParse->db, nByte+sizeof(*pBlock));
+  if( pBlock ){
+    pBlock->pNext = pWInfo->pMemToFree;
+    pBlock->sz = nByte;
+    pWInfo->pMemToFree = pBlock;
+    pBlock++;
+  }
+  return (void*)pBlock;
+}
+SQLITE_PRIVATE void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte){
+  void *pNew = sqlite3WhereMalloc(pWInfo, nByte);
+  if( pNew && pOld ){
+    WhereMemBlock *pOldBlk = (WhereMemBlock*)pOld;
+    pOldBlk--;
+    assert( pOldBlk->sz<nByte );
+    memcpy(pNew, pOld, pOldBlk->sz);
+  }
+  return pNew;
+}
+
+/*
+** Create a new mask for cursor iCursor.
+**
+** There is one cursor per table in the FROM clause.  The number of
+** tables in the FROM clause is limited by a test early in the
+** sqlite3WhereBegin() routine.  So we know that the pMaskSet->ix[]
+** array will never overflow.
+*/
+static void createMask(WhereMaskSet *pMaskSet, int iCursor){
+  assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
+  pMaskSet->ix[pMaskSet->n++] = iCursor;
+}
+
+/*
+** If the right-hand branch of the expression is a TK_COLUMN, then return
+** a pointer to the right-hand branch.  Otherwise, return NULL.
+*/
+static Expr *whereRightSubexprIsColumn(Expr *p){
+  p = sqlite3ExprSkipCollateAndLikely(p->pRight);
+  if( ALWAYS(p!=0) && p->op==TK_COLUMN && !ExprHasProperty(p, EP_FixedCol) ){
+    return p;
+  }
+  return 0;
+}
+
+/*
+** Term pTerm is guaranteed to be a WO_IN term. It may be a component term
+** of a vector IN expression of the form "(x, y, ...) IN (SELECT ...)".
+** This function checks to see if the term is compatible with an index
+** column with affinity idxaff (one of the SQLITE_AFF_XYZ values). If so,
+** it returns a pointer to the name of the collation sequence (e.g. "BINARY"
+** or "NOCASE") used by the comparison in pTerm. If it is not compatible
+** with affinity idxaff, NULL is returned.
+*/
+static SQLITE_NOINLINE const char *indexInAffinityOk(
+  Parse *pParse,
+  WhereTerm *pTerm,
+  u8 idxaff
+){
+  Expr *pX = pTerm->pExpr;
+  Expr inexpr;
+
+  assert( pTerm->eOperator & WO_IN );
+
+  if( sqlite3ExprIsVector(pX->pLeft) ){
+    int iField = pTerm->u.x.iField - 1;
+    inexpr.flags = 0;
+    inexpr.op = TK_EQ;
+    inexpr.pLeft = pX->pLeft->x.pList->a[iField].pExpr;
+    assert( ExprUseXSelect(pX) );
+    inexpr.pRight = pX->x.pSelect->pEList->a[iField].pExpr;
+    pX = &inexpr;
+  }
+
+  if( sqlite3IndexAffinityOk(pX, idxaff) ){
+    CollSeq *pRet = sqlite3ExprCompareCollSeq(pParse, pX);
+    return pRet ? pRet->zName : sqlite3StrBINARY;
+  }
+  return 0;
+}
+
+/*
+** Advance to the next WhereTerm that matches according to the criteria
+** established when the pScan object was initialized by whereScanInit().
+** Return NULL if there are no more matching WhereTerms.
+*/
+static WhereTerm *whereScanNext(WhereScan *pScan){
+  int iCur;            /* The cursor on the LHS of the term */
+  i16 iColumn;         /* The column on the LHS of the term.  -1 for IPK */
+  Expr *pX;            /* An expression being tested */
+  WhereClause *pWC;    /* Shorthand for pScan->pWC */
+  WhereTerm *pTerm;    /* The term being tested */
+  int k = pScan->k;    /* Where to start scanning */
+
+  assert( pScan->iEquiv<=pScan->nEquiv );
+  pWC = pScan->pWC;
+  while(1){
+    iColumn = pScan->aiColumn[pScan->iEquiv-1];
+    iCur = pScan->aiCur[pScan->iEquiv-1];
+    assert( pWC!=0 );
+    assert( iCur>=0 );
+    do{
+      for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
+        assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 || pTerm->leftCursor<0 );
+        if( pTerm->leftCursor==iCur
+         && pTerm->u.x.leftColumn==iColumn
+         && (iColumn!=XN_EXPR
+             || sqlite3ExprCompareSkip(pTerm->pExpr->pLeft,
+                                       pScan->pIdxExpr,iCur)==0)
+         && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_OuterON))
+        ){
+          if( (pTerm->eOperator & WO_EQUIV)!=0
+           && pScan->nEquiv<ArraySize(pScan->aiCur)
+           && (pX = whereRightSubexprIsColumn(pTerm->pExpr))!=0
+          ){
+            int j;
+            for(j=0; j<pScan->nEquiv; j++){
+              if( pScan->aiCur[j]==pX->iTable
+               && pScan->aiColumn[j]==pX->iColumn ){
+                  break;
+              }
+            }
+            if( j==pScan->nEquiv ){
+              pScan->aiCur[j] = pX->iTable;
+              pScan->aiColumn[j] = pX->iColumn;
+              pScan->nEquiv++;
+            }
+          }
+          if( (pTerm->eOperator & pScan->opMask)!=0 ){
+            /* Verify the affinity and collating sequence match */
+            if( pScan->zCollName && (pTerm->eOperator & WO_ISNULL)==0 ){
+              const char *zCollName;
+              Parse *pParse = pWC->pWInfo->pParse;
+              pX = pTerm->pExpr;
+
+              if( (pTerm->eOperator & WO_IN) ){
+                zCollName = indexInAffinityOk(pParse, pTerm, pScan->idxaff);
+                if( !zCollName ) continue;
+              }else{
+                CollSeq *pColl;
+                if( !sqlite3IndexAffinityOk(pX, pScan->idxaff) ){
+                  continue;
+                }
+                assert(pX->pLeft);
+                pColl = sqlite3ExprCompareCollSeq(pParse, pX);
+                zCollName = pColl ? pColl->zName : sqlite3StrBINARY;
+              }
+
+              if( sqlite3StrICmp(zCollName, pScan->zCollName) ){
+                continue;
+              }
+            }
+            if( (pTerm->eOperator & (WO_EQ|WO_IS))!=0
+             && (pX = pTerm->pExpr->pRight, ALWAYS(pX!=0))
+             && pX->op==TK_COLUMN
+             && pX->iTable==pScan->aiCur[0]
+             && pX->iColumn==pScan->aiColumn[0]
+            ){
+              testcase( pTerm->eOperator & WO_IS );
+              continue;
+            }
+            pScan->pWC = pWC;
+            pScan->k = k+1;
+#ifdef WHERETRACE_ENABLED
+            if( sqlite3WhereTrace & 0x20000 ){
+              int ii;
+              sqlite3DebugPrintf("SCAN-TERM %p: nEquiv=%d",
+                 pTerm, pScan->nEquiv);
+              for(ii=0; ii<pScan->nEquiv; ii++){
+                sqlite3DebugPrintf(" {%d:%d}",
+                   pScan->aiCur[ii], pScan->aiColumn[ii]);
+              }
+              sqlite3DebugPrintf("\n");
+            }
+#endif
+            return pTerm;
+          }
+        }
+      }
+      pWC = pWC->pOuter;
+      k = 0;
+    }while( pWC!=0 );
+    if( pScan->iEquiv>=pScan->nEquiv ) break;
+    pWC = pScan->pOrigWC;
+    k = 0;
+    pScan->iEquiv++;
+  }
+  return 0;
+}
+
+/*
+** This is whereScanInit() for the case of an index on an expression.
+** It is factored out into a separate tail-recursion subroutine so that
+** the normal whereScanInit() routine, which is a high-runner, does not
+** need to push registers onto the stack as part of its prologue.
+*/
+static SQLITE_NOINLINE WhereTerm *whereScanInitIndexExpr(WhereScan *pScan){
+  pScan->idxaff = sqlite3ExprAffinity(pScan->pIdxExpr);
+  return whereScanNext(pScan);
+}
+
+/*
+** Initialize a WHERE clause scanner object.  Return a pointer to the
+** first match.  Return NULL if there are no matches.
+**
+** The scanner will be searching the WHERE clause pWC.  It will look
+** for terms of the form "X <op> <expr>" where X is column iColumn of table
+** iCur.   Or if pIdx!=0 then X is column iColumn of index pIdx.  pIdx
+** must be one of the indexes of table iCur.
+**
+** The <op> must be one of the operators described by opMask.
+**
+** If the search is for X and the WHERE clause contains terms of the
+** form X=Y then this routine might also return terms of the form
+** "Y <op> <expr>".  The number of levels of transitivity is limited,
+** but is enough to handle most commonly occurring SQL statements.
+**
+** If X is not the INTEGER PRIMARY KEY then X must be compatible with
+** index pIdx.
+*/
+static WhereTerm *whereScanInit(
+  WhereScan *pScan,       /* The WhereScan object being initialized */
+  WhereClause *pWC,       /* The WHERE clause to be scanned */
+  int iCur,               /* Cursor to scan for */
+  int iColumn,            /* Column to scan for */
+  u32 opMask,             /* Operator(s) to scan for */
+  Index *pIdx             /* Must be compatible with this index */
+){
+  pScan->pOrigWC = pWC;
+  pScan->pWC = pWC;
+  pScan->pIdxExpr = 0;
+  pScan->idxaff = 0;
+  pScan->zCollName = 0;
+  pScan->opMask = opMask;
+  pScan->k = 0;
+  pScan->aiCur[0] = iCur;
+  pScan->nEquiv = 1;
+  pScan->iEquiv = 1;
+  if( pIdx ){
+    int j = iColumn;
+    iColumn = pIdx->aiColumn[j];
+    if( iColumn==pIdx->pTable->iPKey ){
+      iColumn = XN_ROWID;
+    }else if( iColumn>=0 ){
+      pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity;
+      pScan->zCollName = pIdx->azColl[j];
+    }else if( iColumn==XN_EXPR ){
+      pScan->pIdxExpr = pIdx->aColExpr->a[j].pExpr;
+      pScan->zCollName = pIdx->azColl[j];
+      pScan->aiColumn[0] = XN_EXPR;
+      return whereScanInitIndexExpr(pScan);
+    }
+  }else if( iColumn==XN_EXPR ){
+    return 0;
+  }
+  pScan->aiColumn[0] = iColumn;
+  return whereScanNext(pScan);
+}
+
+/*
+** Search for a term in the WHERE clause that is of the form "X <op> <expr>"
+** where X is a reference to the iColumn of table iCur or of index pIdx
+** if pIdx!=0 and <op> is one of the WO_xx operator codes specified by
+** the op parameter.  Return a pointer to the term.  Return 0 if not found.
+**
+** If pIdx!=0 then it must be one of the indexes of table iCur.
+** Search for terms matching the iColumn-th column of pIdx
+** rather than the iColumn-th column of table iCur.
+**
+** The term returned might by Y=<expr> if there is another constraint in
+** the WHERE clause that specifies that X=Y.  Any such constraints will be
+** identified by the WO_EQUIV bit in the pTerm->eOperator field.  The
+** aiCur[]/iaColumn[] arrays hold X and all its equivalents. There are 11
+** slots in aiCur[]/aiColumn[] so that means we can look for X plus up to 10
+** other equivalent values.  Hence a search for X will return <expr> if X=A1
+** and A1=A2 and A2=A3 and ... and A9=A10 and A10=<expr>.
+**
+** If there are multiple terms in the WHERE clause of the form "X <op> <expr>"
+** then try for the one with no dependencies on <expr> - in other words where
+** <expr> is a constant expression of some kind.  Only return entries of
+** the form "X <op> Y" where Y is a column in another table if no terms of
+** the form "X <op> <const-expr>" exist.   If no terms with a constant RHS
+** exist, try to return a term that does not use WO_EQUIV.
+*/
+SQLITE_PRIVATE WhereTerm *sqlite3WhereFindTerm(
+  WhereClause *pWC,     /* The WHERE clause to be searched */
+  int iCur,             /* Cursor number of LHS */
+  int iColumn,          /* Column number of LHS */
+  Bitmask notReady,     /* RHS must not overlap with this mask */
+  u32 op,               /* Mask of WO_xx values describing operator */
+  Index *pIdx           /* Must be compatible with this index, if not NULL */
+){
+  WhereTerm *pResult = 0;
+  WhereTerm *p;
+  WhereScan scan;
+
+  p = whereScanInit(&scan, pWC, iCur, iColumn, op, pIdx);
+  op &= WO_EQ|WO_IS;
+  while( p ){
+    if( (p->prereqRight & notReady)==0 ){
+      if( p->prereqRight==0 && (p->eOperator&op)!=0 ){
+        testcase( p->eOperator & WO_IS );
+        return p;
+      }
+      if( pResult==0 ) pResult = p;
+    }
+    p = whereScanNext(&scan);
+  }
+  return pResult;
+}
+
+/*
+** This function searches pList for an entry that matches the iCol-th column
+** of index pIdx.
+**
+** If such an expression is found, its index in pList->a[] is returned. If
+** no expression is found, -1 is returned.
+*/
+static int findIndexCol(
+  Parse *pParse,                  /* Parse context */
+  ExprList *pList,                /* Expression list to search */
+  int iBase,                      /* Cursor for table associated with pIdx */
+  Index *pIdx,                    /* Index to match column of */
+  int iCol                        /* Column of index to match */
+){
+  int i;
+  const char *zColl = pIdx->azColl[iCol];
+
+  for(i=0; i<pList->nExpr; i++){
+    Expr *p = sqlite3ExprSkipCollateAndLikely(pList->a[i].pExpr);
+    if( ALWAYS(p!=0)
+     && (p->op==TK_COLUMN || p->op==TK_AGG_COLUMN)
+     && p->iColumn==pIdx->aiColumn[iCol]
+     && p->iTable==iBase
+    ){
+      CollSeq *pColl = sqlite3ExprNNCollSeq(pParse, pList->a[i].pExpr);
+      if( 0==sqlite3StrICmp(pColl->zName, zColl) ){
+        return i;
+      }
+    }
+  }
+
+  return -1;
+}
+
+/*
+** Return TRUE if the iCol-th column of index pIdx is NOT NULL
+*/
+static int indexColumnNotNull(Index *pIdx, int iCol){
+  int j;
+  assert( pIdx!=0 );
+  assert( iCol>=0 && iCol<pIdx->nColumn );
+  j = pIdx->aiColumn[iCol];
+  if( j>=0 ){
+    return pIdx->pTable->aCol[j].notNull;
+  }else if( j==(-1) ){
+    return 1;
+  }else{
+    assert( j==(-2) );
+    return 0;  /* Assume an indexed expression can always yield a NULL */
+
+  }
+}
+
+/*
+** Return true if the DISTINCT expression-list passed as the third argument
+** is redundant.
+**
+** A DISTINCT list is redundant if any subset of the columns in the
+** DISTINCT list are collectively unique and individually non-null.
+*/
+static int isDistinctRedundant(
+  Parse *pParse,            /* Parsing context */
+  SrcList *pTabList,        /* The FROM clause */
+  WhereClause *pWC,         /* The WHERE clause */
+  ExprList *pDistinct       /* The result set that needs to be DISTINCT */
+){
+  Table *pTab;
+  Index *pIdx;
+  int i;
+  int iBase;
+
+  /* If there is more than one table or sub-select in the FROM clause of
+  ** this query, then it will not be possible to show that the DISTINCT
+  ** clause is redundant. */
+  if( pTabList->nSrc!=1 ) return 0;
+  iBase = pTabList->a[0].iCursor;
+  pTab = pTabList->a[0].pSTab;
+
+  /* If any of the expressions is an IPK column on table iBase, then return
+  ** true. Note: The (p->iTable==iBase) part of this test may be false if the
+  ** current SELECT is a correlated sub-query.
+  */
+  for(i=0; i<pDistinct->nExpr; i++){
+    Expr *p = sqlite3ExprSkipCollateAndLikely(pDistinct->a[i].pExpr);
+    if( NEVER(p==0) ) continue;
+    if( p->op!=TK_COLUMN && p->op!=TK_AGG_COLUMN ) continue;
+    if( p->iTable==iBase && p->iColumn<0 ) return 1;
+  }
+
+  /* Loop through all indices on the table, checking each to see if it makes
+  ** the DISTINCT qualifier redundant. It does so if:
+  **
+  **   1. The index is itself UNIQUE, and
+  **
+  **   2. All of the columns in the index are either part of the pDistinct
+  **      list, or else the WHERE clause contains a term of the form "col=X",
+  **      where X is a constant value. The collation sequences of the
+  **      comparison and select-list expressions must match those of the index.
+  **
+  **   3. All of those index columns for which the WHERE clause does not
+  **      contain a "col=X" term are subject to a NOT NULL constraint.
+  */
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    if( !IsUniqueIndex(pIdx) ) continue;
+    if( pIdx->pPartIdxWhere ) continue;
+    for(i=0; i<pIdx->nKeyCol; i++){
+      if( 0==sqlite3WhereFindTerm(pWC, iBase, i, ~(Bitmask)0, WO_EQ, pIdx) ){
+        if( findIndexCol(pParse, pDistinct, iBase, pIdx, i)<0 ) break;
+        if( indexColumnNotNull(pIdx, i)==0 ) break;
+      }
+    }
+    if( i==pIdx->nKeyCol ){
+      /* This index implies that the DISTINCT qualifier is redundant. */
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
+
+/*
+** Estimate the logarithm of the input value to base 2.
+*/
+static LogEst estLog(LogEst N){
+  return N<=10 ? 0 : sqlite3LogEst(N) - 33;
+}
+
+/*
+** Convert OP_Column opcodes to OP_Copy in previously generated code.
+**
+** This routine runs over generated VDBE code and translates OP_Column
+** opcodes into OP_Copy when the table is being accessed via co-routine
+** instead of via table lookup.
+**
+** If the iAutoidxCur is not zero, then any OP_Rowid instructions on
+** cursor iTabCur are transformed into OP_Sequence opcode for the
+** iAutoidxCur cursor, in order to generate unique rowids for the
+** automatic index being generated.
+*/
+static void translateColumnToCopy(
+  Parse *pParse,      /* Parsing context */
+  int iStart,         /* Translate from this opcode to the end */
+  int iTabCur,        /* OP_Column/OP_Rowid references to this table */
+  int iRegister,      /* The first column is in this register */
+  int iAutoidxCur     /* If non-zero, cursor of autoindex being generated */
+){
+  Vdbe *v = pParse->pVdbe;
+  VdbeOp *pOp = sqlite3VdbeGetOp(v, iStart);
+  int iEnd = sqlite3VdbeCurrentAddr(v);
+  if( pParse->db->mallocFailed ) return;
+#ifdef SQLITE_DEBUG
+  if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
+    printf("CHECKING for column-to-copy on cursor %d for %d..%d\n",
+            iTabCur, iStart, iEnd);
+  }
+#endif
+  for(; iStart<iEnd; iStart++, pOp++){
+    if( pOp->p1!=iTabCur ) continue;
+    if( pOp->opcode==OP_Column ){
+#ifdef SQLITE_DEBUG
+      if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
+        printf("TRANSLATE OP_Column to OP_Copy at %d\n", iStart);
+      }
+#endif
+      pOp->opcode = OP_Copy;
+      pOp->p1 = pOp->p2 + iRegister;
+      pOp->p2 = pOp->p3;
+      pOp->p3 = 0;
+      pOp->p5 = 2;  /* Cause the MEM_Subtype flag to be cleared */
+    }else if( pOp->opcode==OP_Rowid ){
+#ifdef SQLITE_DEBUG
+      if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
+        printf("TRANSLATE OP_Rowid to OP_Sequence at %d\n", iStart);
+      }
+#endif
+      pOp->opcode = OP_Sequence;
+      pOp->p1 = iAutoidxCur;
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+      if( iAutoidxCur==0 ){
+        pOp->opcode = OP_Null;
+        pOp->p3 = 0;
+      }
+#endif
+    }
+  }
+}
+
+/*
+** Two routines for printing the content of an sqlite3_index_info
+** structure.  Used for testing and debugging only.  If neither
+** SQLITE_TEST or SQLITE_DEBUG are defined, then these routines
+** are no-ops.
+*/
+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(WHERETRACE_ENABLED)
+static void whereTraceIndexInfoInputs(
+  sqlite3_index_info *p,   /* The IndexInfo object */
+  Table *pTab              /* The TABLE that is the virtual table */
+){
+  int i;
+  if( (sqlite3WhereTrace & 0x10)==0 ) return;
+  sqlite3DebugPrintf("sqlite3_index_info inputs for %s:\n", pTab->zName);
+  for(i=0; i<p->nConstraint; i++){
+    sqlite3DebugPrintf(
+       "  constraint[%d]: col=%d termid=%d op=%d usabled=%d collseq=%s\n",
+       i,
+       p->aConstraint[i].iColumn,
+       p->aConstraint[i].iTermOffset,
+       p->aConstraint[i].op,
+       p->aConstraint[i].usable,
+       sqlite3_vtab_collation(p,i));
+  }
+  for(i=0; i<p->nOrderBy; i++){
+    sqlite3DebugPrintf("  orderby[%d]: col=%d desc=%d\n",
+       i,
+       p->aOrderBy[i].iColumn,
+       p->aOrderBy[i].desc);
+  }
+}
+static void whereTraceIndexInfoOutputs(
+  sqlite3_index_info *p,   /* The IndexInfo object */
+  Table *pTab              /* The TABLE that is the virtual table */
+){
+  int i;
+  if( (sqlite3WhereTrace & 0x10)==0 ) return;
+  sqlite3DebugPrintf("sqlite3_index_info outputs for %s:\n", pTab->zName);
+  for(i=0; i<p->nConstraint; i++){
+    sqlite3DebugPrintf("  usage[%d]: argvIdx=%d omit=%d\n",
+       i,
+       p->aConstraintUsage[i].argvIndex,
+       p->aConstraintUsage[i].omit);
+  }
+  sqlite3DebugPrintf("  idxNum=%d\n", p->idxNum);
+  sqlite3DebugPrintf("  idxStr=%s\n", p->idxStr);
+  sqlite3DebugPrintf("  orderByConsumed=%d\n", p->orderByConsumed);
+  sqlite3DebugPrintf("  estimatedCost=%g\n", p->estimatedCost);
+  sqlite3DebugPrintf("  estimatedRows=%lld\n", p->estimatedRows);
+}
+#else
+#define whereTraceIndexInfoInputs(A,B)
+#define whereTraceIndexInfoOutputs(A,B)
+#endif
+
+/*
+** We know that pSrc is an operand of an outer join.  Return true if
+** pTerm is a constraint that is compatible with that join.
+**
+** pTerm must be EP_OuterON if pSrc is the right operand of an
+** outer join.  pTerm can be either EP_OuterON or EP_InnerON if pSrc
+** is the left operand of a RIGHT join.
+**
+** See https://sqlite.org/forum/forumpost/206d99a16dd9212f
+** for an example of a WHERE clause constraints that may not be used on
+** the right table of a RIGHT JOIN because the constraint implies a
+** not-NULL condition on the left table of the RIGHT JOIN.
+*/
+static int constraintCompatibleWithOuterJoin(
+  const WhereTerm *pTerm,       /* WHERE clause term to check */
+  const SrcItem *pSrc           /* Table we are trying to access */
+){
+  assert( (pSrc->fg.jointype&(JT_LEFT|JT_LTORJ|JT_RIGHT))!=0 ); /* By caller */
+  testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LEFT );
+  testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LTORJ );
+  testcase( ExprHasProperty(pTerm->pExpr, EP_OuterON) )
+  testcase( ExprHasProperty(pTerm->pExpr, EP_InnerON) );
+  if( !ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON)
+   || pTerm->pExpr->w.iJoin != pSrc->iCursor
+  ){
+    return 0;
+  }
+  if( (pSrc->fg.jointype & (JT_LEFT|JT_RIGHT))!=0
+   && NEVER(ExprHasProperty(pTerm->pExpr, EP_InnerON))
+  ){
+    return 0;
+  }
+  return 1;
+}
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+/*
+** Return true if column iCol of table pTab seem like it might be a
+** good column to use as part of a query-time index.
+**
+** Current algorithm (subject to improvement!):
+**
+**   1.   If iCol is already the left-most column of some other index,
+**        then return false.
+**
+**   2.   If iCol is part of an existing index that has an aiRowLogEst of
+**        more than 20, then return false.
+**
+**   3.   If no disqualifying conditions above are found, return true.
+**
+** 2025-01-03: I experimented with a new rule that returns false if the
+** the datatype of the column is "BOOLEAN". This did not improve
+** performance on any queries at hand, but it did burn CPU cycles, so the
+** idea was not committed.
+*/
+static SQLITE_NOINLINE int columnIsGoodIndexCandidate(
+  const Table *pTab,
+  int iCol
+){
+  const Index *pIdx;
+  for(pIdx = pTab->pIndex; pIdx!=0; pIdx=pIdx->pNext){
+    int j;
+    for(j=0; j<pIdx->nKeyCol; j++){
+       if( pIdx->aiColumn[j]==iCol ){
+         if( j==0 ) return 0;
+         if( pIdx->hasStat1 && pIdx->aiRowLogEst[j+1]>20 ) return 0;
+         break;
+       }
+    }
+  }
+  return 1;
+}
+#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
+
+
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+/*
+** Return TRUE if the WHERE clause term pTerm is of a form where it
+** could be used with an index to access pSrc, assuming an appropriate
+** index existed.
+*/
+static int termCanDriveIndex(
+  const WhereTerm *pTerm,        /* WHERE clause term to check */
+  const SrcItem *pSrc,           /* Table we are trying to access */
+  const Bitmask notReady         /* Tables in outer loops of the join */
+){
+  char aff;
+  int leftCol;
+
+  if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
+  if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) return 0;
+  assert( (pSrc->fg.jointype & JT_RIGHT)==0 );
+  if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
+   && !constraintCompatibleWithOuterJoin(pTerm,pSrc)
+  ){
+    return 0;  /* See https://sqlite.org/forum/forumpost/51e6959f61 */
+  }
+  if( (pTerm->prereqRight & notReady)!=0 ) return 0;
+  assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+  leftCol = pTerm->u.x.leftColumn;
+  if( leftCol<0 ) return 0;
+  aff = pSrc->pSTab->aCol[leftCol].affinity;
+  if( !sqlite3IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
+  testcase( pTerm->pExpr->op==TK_IS );
+  return columnIsGoodIndexCandidate(pSrc->pSTab, leftCol);
+}
+#endif
+
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+/*
+** Argument pIdx represents an automatic index that the current statement
+** will create and populate. Add an OP_Explain with text of the form:
+**
+**     CREATE AUTOMATIC INDEX ON <table>(<cols>) [WHERE <expr>]
+**
+** This is only required if sqlite3_stmt_scanstatus() is enabled, to
+** associate an SQLITE_SCANSTAT_NCYCLE and SQLITE_SCANSTAT_NLOOP
+** values with. In order to avoid breaking legacy code and test cases,
+** the OP_Explain is not added if this is an EXPLAIN QUERY PLAN command.
+*/
+static void explainAutomaticIndex(
+  Parse *pParse,
+  Index *pIdx,                    /* Automatic index to explain */
+  int bPartial,                   /* True if pIdx is a partial index */
+  int *pAddrExplain               /* OUT: Address of OP_Explain */
+){
+  if( IS_STMT_SCANSTATUS(pParse->db) && pParse->explain!=2 ){
+    Table *pTab = pIdx->pTable;
+    const char *zSep = "";
+    char *zText = 0;
+    int ii = 0;
+    sqlite3_str *pStr = sqlite3_str_new(pParse->db);
+    sqlite3_str_appendf(pStr,"CREATE AUTOMATIC INDEX ON %s(", pTab->zName);
+    assert( pIdx->nColumn>1 );
+    assert( pIdx->aiColumn[pIdx->nColumn-1]==XN_ROWID || !HasRowid(pTab) );
+    for(ii=0; ii<(pIdx->nColumn-1); ii++){
+      const char *zName = 0;
+      int iCol = pIdx->aiColumn[ii];
+
+      zName = pTab->aCol[iCol].zCnName;
+      sqlite3_str_appendf(pStr, "%s%s", zSep, zName);
+      zSep = ", ";
+    }
+    zText = sqlite3_str_finish(pStr);
+    if( zText==0 ){
+      sqlite3OomFault(pParse->db);
+    }else{
+      *pAddrExplain = sqlite3VdbeExplain(
+          pParse, 0, "%s)%s", zText, (bPartial ? " WHERE <expr>" : "")
+      );
+      sqlite3_free(zText);
+    }
+  }
+}
+#else
+# define explainAutomaticIndex(a,b,c,d)
+#endif
+
+/*
+** Generate code to construct the Index object for an automatic index
+** and to set up the WhereLevel object pLevel so that the code generator
+** makes use of the automatic index.
+*/
+static SQLITE_NOINLINE void constructAutomaticIndex(
+  Parse *pParse,              /* The parsing context */
+  WhereClause *pWC,           /* The WHERE clause */
+  const Bitmask notReady,     /* Mask of cursors that are not available */
+  WhereLevel *pLevel          /* Write new index here */
+){
+  int nKeyCol;                /* Number of columns in the constructed index */
+  WhereTerm *pTerm;           /* A single term of the WHERE clause */
+  WhereTerm *pWCEnd;          /* End of pWC->a[] */
+  Index *pIdx;                /* Object describing the transient index */
+  Vdbe *v;                    /* Prepared statement under construction */
+  int addrInit;               /* Address of the initialization bypass jump */
+  Table *pTable;              /* The table being indexed */
+  int addrTop;                /* Top of the index fill loop */
+  int regRecord;              /* Register holding an index record */
+  int n;                      /* Column counter */
+  int i;                      /* Loop counter */
+  int mxBitCol;               /* Maximum column in pSrc->colUsed */
+  CollSeq *pColl;             /* Collating sequence to on a column */
+  WhereLoop *pLoop;           /* The Loop object */
+  char *zNotUsed;             /* Extra space on the end of pIdx */
+  Bitmask idxCols;            /* Bitmap of columns used for indexing */
+  Bitmask extraCols;          /* Bitmap of additional columns */
+  u8 sentWarning = 0;         /* True if a warning has been issued */
+  u8 useBloomFilter = 0;      /* True to also add a Bloom filter */
+  Expr *pPartial = 0;         /* Partial Index Expression */
+  int iContinue = 0;          /* Jump here to skip excluded rows */
+  SrcList *pTabList;          /* The complete FROM clause */
+  SrcItem *pSrc;              /* The FROM clause term to get the next index */
+  int addrCounter = 0;        /* Address where integer counter is initialized */
+  int regBase;                /* Array of registers where record is assembled */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrExp = 0;            /* Address of OP_Explain */
+#endif
+
+  /* Generate code to skip over the creation and initialization of the
+  ** transient index on 2nd and subsequent iterations of the loop. */
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  addrInit = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+
+  /* Count the number of columns that will be added to the index
+  ** and used to match WHERE clause constraints */
+  nKeyCol = 0;
+  pTabList = pWC->pWInfo->pTabList;
+  pSrc = &pTabList->a[pLevel->iFrom];
+  pTable = pSrc->pSTab;
+  pWCEnd = &pWC->a[pWC->nTerm];
+  pLoop = pLevel->pWLoop;
+  idxCols = 0;
+  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
+    Expr *pExpr = pTerm->pExpr;
+    /* Make the automatic index a partial index if there are terms in the
+    ** WHERE clause (or the ON clause of a LEFT join) that constrain which
+    ** rows of the target table (pSrc) that can be used. */
+    if( (pTerm->wtFlags & TERM_VIRTUAL)==0
+     && sqlite3ExprIsSingleTableConstraint(pExpr, pTabList, pLevel->iFrom, 0)
+    ){
+      pPartial = sqlite3ExprAnd(pParse, pPartial,
+                                sqlite3ExprDup(pParse->db, pExpr, 0));
+    }
+    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
+      int iCol;
+      Bitmask cMask;
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      iCol = pTerm->u.x.leftColumn;
+      cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
+      testcase( iCol==BMS );
+      testcase( iCol==BMS-1 );
+      if( !sentWarning ){
+        sqlite3_log(SQLITE_WARNING_AUTOINDEX,
+            "automatic index on %s(%s)", pTable->zName,
+            pTable->aCol[iCol].zCnName);
+        sentWarning = 1;
+      }
+      if( (idxCols & cMask)==0 ){
+        if( whereLoopResize(pParse->db, pLoop, nKeyCol+1) ){
+          goto end_auto_index_create;
+        }
+        pLoop->aLTerm[nKeyCol++] = pTerm;
+        idxCols |= cMask;
+      }
+    }
+  }
+  assert( nKeyCol>0 || pParse->db->mallocFailed );
+  pLoop->u.btree.nEq = pLoop->nLTerm = nKeyCol;
+  pLoop->wsFlags = WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WHERE_INDEXED
+                     | WHERE_AUTO_INDEX;
+
+  /* Count the number of additional columns needed to create a
+  ** covering index.  A "covering index" is an index that contains all
+  ** columns that are needed by the query.  With a covering index, the
+  ** original table never needs to be accessed.  Automatic indices must
+  ** be a covering index because the index will not be updated if the
+  ** original table changes and the index and table cannot both be used
+  ** if they go out of sync.
+  */
+  if( IsView(pTable) ){
+    extraCols = ALLBITS & ~idxCols;
+  }else{
+    extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1));
+  }
+  if( !HasRowid(pTable) ){
+    /* For WITHOUT ROWID tables, ensure that all PRIMARY KEY columns are
+    ** either in the idxCols mask or in the extraCols mask */
+    for(i=0; i<pTable->nCol; i++){
+      if( (pTable->aCol[i].colFlags & COLFLAG_PRIMKEY)==0 ) continue;
+      if( i>=BMS-1 ){
+        extraCols |= MASKBIT(BMS-1);
+        break;
+      }
+      if( idxCols & MASKBIT(i) ) continue;
+      extraCols |= MASKBIT(i);
+    }
+  }
+  mxBitCol = MIN(BMS-1,pTable->nCol);
+  testcase( pTable->nCol==BMS-1 );
+  testcase( pTable->nCol==BMS-2 );
+  for(i=0; i<mxBitCol; i++){
+    if( extraCols & MASKBIT(i) ) nKeyCol++;
+  }
+  if( pSrc->colUsed & MASKBIT(BMS-1) ){
+    nKeyCol += pTable->nCol - BMS + 1;
+  }
+
+  /* Construct the Index object to describe this index */
+  pIdx = sqlite3AllocateIndexObject(pParse->db, nKeyCol+HasRowid(pTable),
+                                    0, &zNotUsed);
+  if( pIdx==0 ) goto end_auto_index_create;
+  pLoop->u.btree.pIndex = pIdx;
+  pIdx->zName = "auto-index";
+  pIdx->pTable = pTable;
+  n = 0;
+  idxCols = 0;
+  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
+    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
+      int iCol;
+      Bitmask cMask;
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      iCol = pTerm->u.x.leftColumn;
+      cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
+      testcase( iCol==BMS-1 );
+      testcase( iCol==BMS );
+      if( (idxCols & cMask)==0 ){
+        Expr *pX = pTerm->pExpr;
+        idxCols |= cMask;
+        pIdx->aiColumn[n] = pTerm->u.x.leftColumn;
+        pColl = sqlite3ExprCompareCollSeq(pParse, pX);
+        assert( pColl!=0 || pParse->nErr>0 ); /* TH3 collate01.800 */
+        pIdx->azColl[n] = pColl ? pColl->zName : sqlite3StrBINARY;
+        n++;
+        if( ALWAYS(pX->pLeft!=0)
+         && sqlite3ExprAffinity(pX->pLeft)!=SQLITE_AFF_TEXT
+        ){
+          /* TUNING: only use a Bloom filter on an automatic index
+          ** if one or more key columns has the ability to hold numeric
+          ** values, since strings all have the same hash in the Bloom
+          ** filter implementation and hence a Bloom filter on a text column
+          ** is not usually helpful. */
+          useBloomFilter = 1;
+        }
+      }
+    }
+  }
+  assert( (u32)n==pLoop->u.btree.nEq );
+
+  /* Add additional columns needed to make the automatic index into
+  ** a covering index */
+  for(i=0; i<mxBitCol; i++){
+    if( extraCols & MASKBIT(i) ){
+      pIdx->aiColumn[n] = i;
+      pIdx->azColl[n] = sqlite3StrBINARY;
+      n++;
+    }
+  }
+  if( pSrc->colUsed & MASKBIT(BMS-1) ){
+    for(i=BMS-1; i<pTable->nCol; i++){
+      pIdx->aiColumn[n] = i;
+      pIdx->azColl[n] = sqlite3StrBINARY;
+      n++;
+    }
+  }
+  assert( n==nKeyCol );
+  if( HasRowid(pTable) ){
+    pIdx->aiColumn[n] = XN_ROWID;
+    pIdx->azColl[n] = sqlite3StrBINARY;
+  }
+
+  /* Create the automatic index */
+  explainAutomaticIndex(pParse, pIdx, pPartial!=0, &addrExp);
+  assert( pLevel->iIdxCur>=0 );
+  pLevel->iIdxCur = pParse->nTab++;
+  sqlite3VdbeAddOp2(v, OP_OpenAutoindex, pLevel->iIdxCur, nKeyCol+1);
+  sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+  VdbeComment((v, "for %s", pTable->zName));
+  if( OptimizationEnabled(pParse->db, SQLITE_BloomFilter) && useBloomFilter ){
+    sqlite3WhereExplainBloomFilter(pParse, pWC->pWInfo, pLevel);
+    pLevel->regFilter = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Blob, 10000, pLevel->regFilter);
+  }
+
+  /* Fill the automatic index with content */
+  assert( pSrc == &pWC->pWInfo->pTabList->a[pLevel->iFrom] );
+  if( pSrc->fg.viaCoroutine ){
+    int regYield;
+    Subquery *pSubq;
+    assert( pSrc->fg.isSubquery );
+    pSubq = pSrc->u4.pSubq;
+    assert( pSubq!=0 );
+    regYield = pSubq->regReturn;
+    addrCounter = sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
+    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pSubq->addrFillSub);
+    addrTop =  sqlite3VdbeAddOp1(v, OP_Yield, regYield);
+    VdbeCoverage(v);
+    VdbeComment((v, "next row of %s", pSrc->pSTab->zName));
+  }else{
+    addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur); VdbeCoverage(v);
+  }
+  if( pPartial ){
+    iContinue = sqlite3VdbeMakeLabel(pParse);
+    sqlite3ExprIfFalse(pParse, pPartial, iContinue, SQLITE_JUMPIFNULL);
+    pLoop->wsFlags |= WHERE_PARTIALIDX;
+  }
+  regRecord = sqlite3GetTempReg(pParse);
+  regBase = sqlite3GenerateIndexKey(
+      pParse, pIdx, pLevel->iTabCur, regRecord, 0, 0, 0, 0
+  );
+  if( pLevel->regFilter ){
+    sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0,
+                         regBase, pLoop->u.btree.nEq);
+  }
+  sqlite3VdbeScanStatusCounters(v, addrExp, addrExp, sqlite3VdbeCurrentAddr(v));
+  sqlite3VdbeAddOp2(v, OP_IdxInsert, pLevel->iIdxCur, regRecord);
+  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+  if( pPartial ) sqlite3VdbeResolveLabel(v, iContinue);
+  if( pSrc->fg.viaCoroutine ){
+    assert( pSrc->fg.isSubquery && pSrc->u4.pSubq!=0 );
+    sqlite3VdbeChangeP2(v, addrCounter, regBase+n);
+    testcase( pParse->db->mallocFailed );
+    assert( pLevel->iIdxCur>0 );
+    translateColumnToCopy(pParse, addrTop, pLevel->iTabCur,
+                          pSrc->u4.pSubq->regResult, pLevel->iIdxCur);
+    sqlite3VdbeGoto(v, addrTop);
+    pSrc->fg.viaCoroutine = 0;
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1); VdbeCoverage(v);
+    sqlite3VdbeChangeP5(v, SQLITE_STMTSTATUS_AUTOINDEX);
+  }
+  sqlite3VdbeJumpHere(v, addrTop);
+  sqlite3ReleaseTempReg(pParse, regRecord);
+
+  /* Jump here when skipping the initialization */
+  sqlite3VdbeJumpHere(v, addrInit);
+  sqlite3VdbeScanStatusRange(v, addrExp, addrExp, -1);
+
+end_auto_index_create:
+  sqlite3ExprDelete(pParse->db, pPartial);
+}
+#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
+
+/*
+** Generate bytecode that will initialize a Bloom filter that is appropriate
+** for pLevel.
+**
+** If there are inner loops within pLevel that have the WHERE_BLOOMFILTER
+** flag set, initialize a Bloomfilter for them as well.  Except don't do
+** this recursive initialization if the SQLITE_BloomPulldown optimization has
+** been turned off.
+**
+** When the Bloom filter is initialized, the WHERE_BLOOMFILTER flag is cleared
+** from the loop, but the regFilter value is set to a register that implements
+** the Bloom filter.  When regFilter is positive, the
+** sqlite3WhereCodeOneLoopStart() will generate code to test the Bloom filter
+** and skip the subsequence B-Tree seek if the Bloom filter indicates that
+** no matching rows exist.
+**
+** This routine may only be called if it has previously been determined that
+** the loop would benefit from a Bloom filter, and the WHERE_BLOOMFILTER bit
+** is set.
+*/
+static SQLITE_NOINLINE void sqlite3ConstructBloomFilter(
+  WhereInfo *pWInfo,    /* The WHERE clause */
+  int iLevel,           /* Index in pWInfo->a[] that is pLevel */
+  WhereLevel *pLevel,   /* Make a Bloom filter for this FROM term */
+  Bitmask notReady      /* Loops that are not ready */
+){
+  int addrOnce;                        /* Address of opening OP_Once */
+  int addrTop;                         /* Address of OP_Rewind */
+  int addrCont;                        /* Jump here to skip a row */
+  const WhereTerm *pTerm;              /* For looping over WHERE clause terms */
+  const WhereTerm *pWCEnd;             /* Last WHERE clause term */
+  Parse *pParse = pWInfo->pParse;      /* Parsing context */
+  Vdbe *v = pParse->pVdbe;             /* VDBE under construction */
+  WhereLoop *pLoop = pLevel->pWLoop;   /* The loop being coded */
+  int iCur;                            /* Cursor for table getting the filter */
+  IndexedExpr *saved_pIdxEpr;          /* saved copy of Parse.pIdxEpr */
+  IndexedExpr *saved_pIdxPartExpr;     /* saved copy of Parse.pIdxPartExpr */
+
+  saved_pIdxEpr = pParse->pIdxEpr;
+  saved_pIdxPartExpr = pParse->pIdxPartExpr;
+  pParse->pIdxEpr = 0;
+  pParse->pIdxPartExpr = 0;
+
+  assert( pLoop!=0 );
+  assert( v!=0 );
+  assert( pLoop->wsFlags & WHERE_BLOOMFILTER );
+  assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 );
+
+  addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+  do{
+    const SrcList *pTabList;
+    const SrcItem *pItem;
+    const Table *pTab;
+    u64 sz;
+    int iSrc;
+    sqlite3WhereExplainBloomFilter(pParse, pWInfo, pLevel);
+    addrCont = sqlite3VdbeMakeLabel(pParse);
+    iCur = pLevel->iTabCur;
+    pLevel->regFilter = ++pParse->nMem;
+
+    /* The Bloom filter is a Blob held in a register.  Initialize it
+    ** to zero-filled blob of at least 80K bits, but maybe more if the
+    ** estimated size of the table is larger.  We could actually
+    ** measure the size of the table at run-time using OP_Count with
+    ** P3==1 and use that value to initialize the blob.  But that makes
+    ** testing complicated.  By basing the blob size on the value in the
+    ** sqlite_stat1 table, testing is much easier.
+    */
+    pTabList = pWInfo->pTabList;
+    iSrc = pLevel->iFrom;
+    pItem = &pTabList->a[iSrc];
+    assert( pItem!=0 );
+    pTab = pItem->pSTab;
+    assert( pTab!=0 );
+    sz = sqlite3LogEstToInt(pTab->nRowLogEst);
+    if( sz<10000 ){
+      sz = 10000;
+    }else if( sz>10000000 ){
+      sz = 10000000;
+    }
+    sqlite3VdbeAddOp2(v, OP_Blob, (int)sz, pLevel->regFilter);
+
+    addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
+    pWCEnd = &pWInfo->sWC.a[pWInfo->sWC.nTerm];
+    for(pTerm=pWInfo->sWC.a; pTerm<pWCEnd; pTerm++){
+      Expr *pExpr = pTerm->pExpr;
+      if( (pTerm->wtFlags & TERM_VIRTUAL)==0
+       && sqlite3ExprIsSingleTableConstraint(pExpr, pTabList, iSrc, 0)
+      ){
+        sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
+      }
+    }
+    if( pLoop->wsFlags & WHERE_IPK ){
+      int r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, r1);
+      sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, 1);
+      sqlite3ReleaseTempReg(pParse, r1);
+    }else{
+      Index *pIdx = pLoop->u.btree.pIndex;
+      int n = pLoop->u.btree.nEq;
+      int r1 = sqlite3GetTempRange(pParse, n);
+      int jj;
+      for(jj=0; jj<n; jj++){
+        assert( pIdx->pTable==pItem->pSTab );
+        sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iCur, jj, r1+jj);
+      }
+      sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, n);
+      sqlite3ReleaseTempRange(pParse, r1, n);
+    }
+    sqlite3VdbeResolveLabel(v, addrCont);
+    sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1);
+    VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addrTop);
+    pLoop->wsFlags &= ~WHERE_BLOOMFILTER;
+    if( OptimizationDisabled(pParse->db, SQLITE_BloomPulldown) ) break;
+    while( ++iLevel < pWInfo->nLevel ){
+      const SrcItem *pTabItem;
+      pLevel = &pWInfo->a[iLevel];
+      pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
+      if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ) ) continue;
+      pLoop = pLevel->pWLoop;
+      if( NEVER(pLoop==0) ) continue;
+      if( pLoop->prereq & notReady ) continue;
+      if( (pLoop->wsFlags & (WHERE_BLOOMFILTER|WHERE_COLUMN_IN))
+                 ==WHERE_BLOOMFILTER
+      ){
+        /* This is a candidate for bloom-filter pull-down (early evaluation).
+        ** The test that WHERE_COLUMN_IN is omitted is important, as we are
+        ** not able to do early evaluation of bloom filters that make use of
+        ** the IN operator */
+        break;
+      }
+    }
+  }while( iLevel < pWInfo->nLevel );
+  sqlite3VdbeJumpHere(v, addrOnce);
+  pParse->pIdxEpr = saved_pIdxEpr;
+  pParse->pIdxPartExpr = saved_pIdxPartExpr;
+}
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Return term iTerm of the WhereClause passed as the first argument. Terms
+** are numbered from 0 upwards, starting with the terms in pWC->a[], then
+** those in pWC->pOuter->a[] (if any), and so on.
+*/
+static WhereTerm *termFromWhereClause(WhereClause *pWC, int iTerm){
+  WhereClause *p;
+  for(p=pWC; p; p=p->pOuter){
+    if( iTerm<p->nTerm ) return &p->a[iTerm];
+    iTerm -= p->nTerm;
+  }
+  return 0;
+}
+
+/*
+** Allocate and populate an sqlite3_index_info structure. It is the
+** responsibility of the caller to eventually release the structure
+** by passing the pointer returned by this function to freeIndexInfo().
+*/
+static sqlite3_index_info *allocateIndexInfo(
+  WhereInfo *pWInfo,              /* The WHERE clause */
+  WhereClause *pWC,               /* The WHERE clause being analyzed */
+  Bitmask mUnusable,              /* Ignore terms with these prereqs */
+  SrcItem *pSrc,                  /* The FROM clause term that is the vtab */
+  u16 *pmNoOmit                   /* Mask of terms not to omit */
+){
+  int i, j;
+  int nTerm;
+  Parse *pParse = pWInfo->pParse;
+  struct sqlite3_index_constraint *pIdxCons;
+  struct sqlite3_index_orderby *pIdxOrderBy;
+  struct sqlite3_index_constraint_usage *pUsage;
+  struct HiddenIndexInfo *pHidden;
+  WhereTerm *pTerm;
+  int nOrderBy;
+  sqlite3_index_info *pIdxInfo;
+  u16 mNoOmit = 0;
+  const Table *pTab;
+  int eDistinct = 0;
+  ExprList *pOrderBy = pWInfo->pOrderBy;
+  WhereClause *p;
+
+  assert( pSrc!=0 );
+  pTab = pSrc->pSTab;
+  assert( pTab!=0 );
+  assert( IsVirtual(pTab) );
+
+  /* Find all WHERE clause constraints referring to this virtual table.
+  ** Mark each term with the TERM_OK flag.  Set nTerm to the number of
+  ** terms found.
+  */
+  for(p=pWC, nTerm=0; p; p=p->pOuter){
+    for(i=0, pTerm=p->a; i<p->nTerm; i++, pTerm++){
+      pTerm->wtFlags &= ~TERM_OK;
+      if( pTerm->leftCursor != pSrc->iCursor ) continue;
+      if( pTerm->prereqRight & mUnusable ) continue;
+      assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
+      testcase( pTerm->eOperator & WO_IN );
+      testcase( pTerm->eOperator & WO_ISNULL );
+      testcase( pTerm->eOperator & WO_IS );
+      testcase( pTerm->eOperator & WO_ALL );
+      if( (pTerm->eOperator & ~(WO_EQUIV))==0 ) continue;
+      if( pTerm->wtFlags & TERM_VNULL ) continue;
+
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      assert( pTerm->u.x.leftColumn>=XN_ROWID );
+      assert( pTerm->u.x.leftColumn<pTab->nCol );
+      if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
+          && !constraintCompatibleWithOuterJoin(pTerm,pSrc)
+        ){
+        continue;
+      }
+      nTerm++;
+      pTerm->wtFlags |= TERM_OK;
+    }
+  }
+
+  /* If the ORDER BY clause contains only columns in the current
+  ** virtual table then allocate space for the aOrderBy part of
+  ** the sqlite3_index_info structure.
+  */
+  nOrderBy = 0;
+  if( pOrderBy ){
+    int n = pOrderBy->nExpr;
+    for(i=0; i<n; i++){
+      Expr *pExpr = pOrderBy->a[i].pExpr;
+      Expr *pE2;
+
+      /* Skip over constant terms in the ORDER BY clause */
+      if( sqlite3ExprIsConstant(0, pExpr) ){
+        continue;
+      }
+
+      /* Virtual tables are unable to deal with NULLS FIRST */
+      if( pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_BIGNULL ) break;
+
+      /* First case - a direct column references without a COLLATE operator */
+      if( pExpr->op==TK_COLUMN && pExpr->iTable==pSrc->iCursor ){
+        assert( pExpr->iColumn>=XN_ROWID && pExpr->iColumn<pTab->nCol );
+        continue;
+      }
+
+      /* 2nd case - a column reference with a COLLATE operator.  Only match
+      ** of the COLLATE operator matches the collation of the column. */
+      if( pExpr->op==TK_COLLATE
+       && (pE2 = pExpr->pLeft)->op==TK_COLUMN
+       && pE2->iTable==pSrc->iCursor
+      ){
+        const char *zColl;  /* The collating sequence name */
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        assert( pExpr->u.zToken!=0 );
+        assert( pE2->iColumn>=XN_ROWID && pE2->iColumn<pTab->nCol );
+        pExpr->iColumn = pE2->iColumn;
+        if( pE2->iColumn<0 ) continue;  /* Collseq does not matter for rowid */
+        zColl = sqlite3ColumnColl(&pTab->aCol[pE2->iColumn]);
+        if( zColl==0 ) zColl = sqlite3StrBINARY;
+        if( sqlite3_stricmp(pExpr->u.zToken, zColl)==0 ) continue;
+      }
+
+      /* No matches cause a break out of the loop */
+      break;
+    }
+    if( i==n ){
+      nOrderBy = n;
+      if( (pWInfo->wctrlFlags & WHERE_DISTINCTBY) && !pSrc->fg.rowidUsed ){
+        eDistinct = 2 + ((pWInfo->wctrlFlags & WHERE_SORTBYGROUP)!=0);
+      }else if( pWInfo->wctrlFlags & WHERE_GROUPBY ){
+        eDistinct = 1;
+      }
+    }
+  }
+
+  /* Allocate the sqlite3_index_info structure
+  */
+  pIdxInfo = sqlite3DbMallocZero(pParse->db, sizeof(*pIdxInfo)
+                           + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
+                           + sizeof(*pIdxOrderBy)*nOrderBy + sizeof(*pHidden)
+                           + sizeof(sqlite3_value*)*nTerm );
+  if( pIdxInfo==0 ){
+    sqlite3ErrorMsg(pParse, "out of memory");
+    return 0;
+  }
+  pHidden = (struct HiddenIndexInfo*)&pIdxInfo[1];
+  pIdxCons = (struct sqlite3_index_constraint*)&pHidden->aRhs[nTerm];
+  pIdxOrderBy = (struct sqlite3_index_orderby*)&pIdxCons[nTerm];
+  pUsage = (struct sqlite3_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
+  pIdxInfo->aConstraint = pIdxCons;
+  pIdxInfo->aOrderBy = pIdxOrderBy;
+  pIdxInfo->aConstraintUsage = pUsage;
+  pIdxInfo->colUsed = (sqlite3_int64)pSrc->colUsed;
+  if( HasRowid(pTab)==0 ){
+    /* Ensure that all bits associated with PK columns are set. This is to
+    ** ensure they are available for cases like RIGHT joins or OR loops. */
+    Index *pPk = sqlite3PrimaryKeyIndex((Table*)pTab);
+    assert( pPk!=0 );
+    for(i=0; i<pPk->nKeyCol; i++){
+      int iCol = pPk->aiColumn[i];
+      assert( iCol>=0 );
+      if( iCol>=BMS-1 ) iCol = BMS-1;
+      pIdxInfo->colUsed |= MASKBIT(iCol);
+    }
+  }
+  pHidden->pWC = pWC;
+  pHidden->pParse = pParse;
+  pHidden->eDistinct = eDistinct;
+  pHidden->mIn = 0;
+  for(p=pWC, i=j=0; p; p=p->pOuter){
+    int nLast = i+p->nTerm;;
+    for(pTerm=p->a; i<nLast; i++, pTerm++){
+      u16 op;
+      if( (pTerm->wtFlags & TERM_OK)==0 ) continue;
+      pIdxCons[j].iColumn = pTerm->u.x.leftColumn;
+      pIdxCons[j].iTermOffset = i;
+      op = pTerm->eOperator & WO_ALL;
+      if( op==WO_IN ){
+        if( (pTerm->wtFlags & TERM_SLICE)==0 ){
+          pHidden->mIn |= SMASKBIT32(j);
+        }
+        op = WO_EQ;
+      }
+      if( op==WO_AUX ){
+        pIdxCons[j].op = pTerm->eMatchOp;
+      }else if( op & (WO_ISNULL|WO_IS) ){
+        if( op==WO_ISNULL ){
+          pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_ISNULL;
+        }else{
+          pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_IS;
+        }
+      }else{
+        pIdxCons[j].op = (u8)op;
+        /* The direct assignment in the previous line is possible only because
+        ** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical.  The
+        ** following asserts verify this fact. */
+        assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ );
+        assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT );
+        assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
+        assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
+        assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
+        assert( pTerm->eOperator&(WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_AUX) );
+
+        if( op & (WO_LT|WO_LE|WO_GT|WO_GE)
+            && sqlite3ExprIsVector(pTerm->pExpr->pRight)
+          ){
+          testcase( j!=i );
+          if( j<16 ) mNoOmit |= (1 << j);
+          if( op==WO_LT ) pIdxCons[j].op = WO_LE;
+          if( op==WO_GT ) pIdxCons[j].op = WO_GE;
+        }
+      }
+
+      j++;
+    }
+  }
+  assert( j==nTerm );
+  pIdxInfo->nConstraint = j;
+  for(i=j=0; i<nOrderBy; i++){
+    Expr *pExpr = pOrderBy->a[i].pExpr;
+    if( sqlite3ExprIsConstant(0, pExpr) ) continue;
+    assert( pExpr->op==TK_COLUMN
+         || (pExpr->op==TK_COLLATE && pExpr->pLeft->op==TK_COLUMN
+              && pExpr->iColumn==pExpr->pLeft->iColumn) );
+    pIdxOrderBy[j].iColumn = pExpr->iColumn;
+    pIdxOrderBy[j].desc = pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_DESC;
+    j++;
+  }
+  pIdxInfo->nOrderBy = j;
+
+  *pmNoOmit = mNoOmit;
+  return pIdxInfo;
+}
+
+/*
+** Free and zero the sqlite3_index_info.idxStr value if needed.
+*/
+static void freeIdxStr(sqlite3_index_info *pIdxInfo){
+  if( pIdxInfo->needToFreeIdxStr ){
+    sqlite3_free(pIdxInfo->idxStr);
+    pIdxInfo->idxStr = 0;
+    pIdxInfo->needToFreeIdxStr = 0;
+  }
+}
+
+/*
+** Free an sqlite3_index_info structure allocated by allocateIndexInfo()
+** and possibly modified by xBestIndex methods.
+*/
+static void freeIndexInfo(sqlite3 *db, sqlite3_index_info *pIdxInfo){
+  HiddenIndexInfo *pHidden;
+  int i;
+  assert( pIdxInfo!=0 );
+  pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  assert( pHidden->pParse!=0 );
+  assert( pHidden->pParse->db==db );
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    sqlite3ValueFree(pHidden->aRhs[i]); /* IMP: R-14553-25174 */
+    pHidden->aRhs[i] = 0;
+  }
+  freeIdxStr(pIdxInfo);
+  sqlite3DbFree(db, pIdxInfo);
+}
+
+/*
+** The table object reference passed as the second argument to this function
+** must represent a virtual table. This function invokes the xBestIndex()
+** method of the virtual table with the sqlite3_index_info object that
+** comes in as the 3rd argument to this function.
+**
+** If an error occurs, pParse is populated with an error message and an
+** appropriate error code is returned.  A return of SQLITE_CONSTRAINT from
+** xBestIndex is not considered an error.  SQLITE_CONSTRAINT indicates that
+** the current configuration of "unusable" flags in sqlite3_index_info can
+** not result in a valid plan.
+**
+** Whether or not an error is returned, it is the responsibility of the
+** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates
+** that this is required.
+*/
+static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){
+  int rc;
+  sqlite3_vtab *pVtab;
+
+  assert( IsVirtual(pTab) );
+  pVtab = sqlite3GetVTable(pParse->db, pTab)->pVtab;
+  whereTraceIndexInfoInputs(p, pTab);
+  pParse->db->nSchemaLock++;
+  rc = pVtab->pModule->xBestIndex(pVtab, p);
+  pParse->db->nSchemaLock--;
+  whereTraceIndexInfoOutputs(p, pTab);
+
+  if( rc!=SQLITE_OK && rc!=SQLITE_CONSTRAINT ){
+    if( rc==SQLITE_NOMEM ){
+      sqlite3OomFault(pParse->db);
+    }else if( !pVtab->zErrMsg ){
+      sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc));
+    }else{
+      sqlite3ErrorMsg(pParse, "%s", pVtab->zErrMsg);
+    }
+  }
+  if( pTab->u.vtab.p->bAllSchemas ){
+    sqlite3VtabUsesAllSchemas(pParse);
+  }
+  sqlite3_free(pVtab->zErrMsg);
+  pVtab->zErrMsg = 0;
+  return rc;
+}
+#endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) */
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Estimate the location of a particular key among all keys in an
+** index.  Store the results in aStat as follows:
+**
+**    aStat[0]      Est. number of rows less than pRec
+**    aStat[1]      Est. number of rows equal to pRec
+**
+** Return the index of the sample that is the smallest sample that
+** is greater than or equal to pRec. Note that this index is not an index
+** into the aSample[] array - it is an index into a virtual set of samples
+** based on the contents of aSample[] and the number of fields in record
+** pRec.
+*/
+static int whereKeyStats(
+  Parse *pParse,              /* Database connection */
+  Index *pIdx,                /* Index to consider domain of */
+  UnpackedRecord *pRec,       /* Vector of values to consider */
+  int roundUp,                /* Round up if true.  Round down if false */
+  tRowcnt *aStat              /* OUT: stats written here */
+){
+  IndexSample *aSample = pIdx->aSample;
+  int iCol;                   /* Index of required stats in anEq[] etc. */
+  int i;                      /* Index of first sample >= pRec */
+  int iSample;                /* Smallest sample larger than or equal to pRec */
+  int iMin = 0;               /* Smallest sample not yet tested */
+  int iTest;                  /* Next sample to test */
+  int res;                    /* Result of comparison operation */
+  int nField;                 /* Number of fields in pRec */
+  tRowcnt iLower = 0;         /* anLt[] + anEq[] of largest sample pRec is > */
+
+#ifndef SQLITE_DEBUG
+  UNUSED_PARAMETER( pParse );
+#endif
+  assert( pRec!=0 );
+  assert( pIdx->nSample>0 );
+  assert( pRec->nField>0 );
+
+
+  /* Do a binary search to find the first sample greater than or equal
+  ** to pRec. If pRec contains a single field, the set of samples to search
+  ** is simply the aSample[] array. If the samples in aSample[] contain more
+  ** than one fields, all fields following the first are ignored.
+  **
+  ** If pRec contains N fields, where N is more than one, then as well as the
+  ** samples in aSample[] (truncated to N fields), the search also has to
+  ** consider prefixes of those samples. For example, if the set of samples
+  ** in aSample is:
+  **
+  **     aSample[0] = (a, 5)
+  **     aSample[1] = (a, 10)
+  **     aSample[2] = (b, 5)
+  **     aSample[3] = (c, 100)
+  **     aSample[4] = (c, 105)
+  **
+  ** Then the search space should ideally be the samples above and the
+  ** unique prefixes [a], [b] and [c]. But since that is hard to organize,
+  ** the code actually searches this set:
+  **
+  **     0: (a)
+  **     1: (a, 5)
+  **     2: (a, 10)
+  **     3: (a, 10)
+  **     4: (b)
+  **     5: (b, 5)
+  **     6: (c)
+  **     7: (c, 100)
+  **     8: (c, 105)
+  **     9: (c, 105)
+  **
+  ** For each sample in the aSample[] array, N samples are present in the
+  ** effective sample array. In the above, samples 0 and 1 are based on
+  ** sample aSample[0]. Samples 2 and 3 on aSample[1] etc.
+  **
+  ** Often, sample i of each block of N effective samples has (i+1) fields.
+  ** Except, each sample may be extended to ensure that it is greater than or
+  ** equal to the previous sample in the array. For example, in the above,
+  ** sample 2 is the first sample of a block of N samples, so at first it
+  ** appears that it should be 1 field in size. However, that would make it
+  ** smaller than sample 1, so the binary search would not work. As a result,
+  ** it is extended to two fields. The duplicates that this creates do not
+  ** cause any problems.
+  */
+  if( !HasRowid(pIdx->pTable) && IsPrimaryKeyIndex(pIdx) ){
+    nField = pIdx->nKeyCol;
+  }else{
+    nField = pIdx->nColumn;
+  }
+  nField = MIN(pRec->nField, nField);
+  iCol = 0;
+  iSample = pIdx->nSample * nField;
+  do{
+    int iSamp;                    /* Index in aSample[] of test sample */
+    int n;                        /* Number of fields in test sample */
+
+    iTest = (iMin+iSample)/2;
+    iSamp = iTest / nField;
+    if( iSamp>0 ){
+      /* The proposed effective sample is a prefix of sample aSample[iSamp].
+      ** Specifically, the shortest prefix of at least (1 + iTest%nField)
+      ** fields that is greater than the previous effective sample.  */
+      for(n=(iTest % nField) + 1; n<nField; n++){
+        if( aSample[iSamp-1].anLt[n-1]!=aSample[iSamp].anLt[n-1] ) break;
+      }
+    }else{
+      n = iTest + 1;
+    }
+
+    pRec->nField = n;
+    res = sqlite3VdbeRecordCompare(aSample[iSamp].n, aSample[iSamp].p, pRec);
+    if( res<0 ){
+      iLower = aSample[iSamp].anLt[n-1] + aSample[iSamp].anEq[n-1];
+      iMin = iTest+1;
+    }else if( res==0 && n<nField ){
+      iLower = aSample[iSamp].anLt[n-1];
+      iMin = iTest+1;
+      res = -1;
+    }else{
+      iSample = iTest;
+      iCol = n-1;
+    }
+  }while( res && iMin<iSample );
+  i = iSample / nField;
+
+#ifdef SQLITE_DEBUG
+  /* The following assert statements check that the binary search code
+  ** above found the right answer. This block serves no purpose other
+  ** than to invoke the asserts.  */
+  if( pParse->db->mallocFailed==0 ){
+    if( res==0 ){
+      /* If (res==0) is true, then pRec must be equal to sample i. */
+      assert( i<pIdx->nSample );
+      assert( iCol==nField-1 );
+      pRec->nField = nField;
+      assert( 0==sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)
+           || pParse->db->mallocFailed
+      );
+    }else{
+      /* Unless i==pIdx->nSample, indicating that pRec is larger than
+      ** all samples in the aSample[] array, pRec must be smaller than the
+      ** (iCol+1) field prefix of sample i.  */
+      assert( i<=pIdx->nSample && i>=0 );
+      pRec->nField = iCol+1;
+      assert( i==pIdx->nSample
+           || sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)>0
+           || pParse->db->mallocFailed );
+
+      /* if i==0 and iCol==0, then record pRec is smaller than all samples
+      ** in the aSample[] array. Otherwise, if (iCol>0) then pRec must
+      ** be greater than or equal to the (iCol) field prefix of sample i.
+      ** If (i>0), then pRec must also be greater than sample (i-1).  */
+      if( iCol>0 ){
+        pRec->nField = iCol;
+        assert( sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)<=0
+             || pParse->db->mallocFailed || CORRUPT_DB );
+      }
+      if( i>0 ){
+        pRec->nField = nField;
+        assert( sqlite3VdbeRecordCompare(aSample[i-1].n, aSample[i-1].p, pRec)<0
+             || pParse->db->mallocFailed || CORRUPT_DB );
+      }
+    }
+  }
+#endif /* ifdef SQLITE_DEBUG */
+
+  if( res==0 ){
+    /* Record pRec is equal to sample i */
+    assert( iCol==nField-1 );
+    aStat[0] = aSample[i].anLt[iCol];
+    aStat[1] = aSample[i].anEq[iCol];
+  }else{
+    /* At this point, the (iCol+1) field prefix of aSample[i] is the first
+    ** sample that is greater than pRec. Or, if i==pIdx->nSample then pRec
+    ** is larger than all samples in the array. */
+    tRowcnt iUpper, iGap;
+    if( i>=pIdx->nSample ){
+      iUpper = pIdx->nRowEst0;
+    }else{
+      iUpper = aSample[i].anLt[iCol];
+    }
+
+    if( iLower>=iUpper ){
+      iGap = 0;
+    }else{
+      iGap = iUpper - iLower;
+    }
+    if( roundUp ){
+      iGap = (iGap*2)/3;
+    }else{
+      iGap = iGap/3;
+    }
+    aStat[0] = iLower + iGap;
+    aStat[1] = pIdx->aAvgEq[nField-1];
+  }
+
+  /* Restore the pRec->nField value before returning.  */
+  pRec->nField = nField;
+  return i;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+/*
+** If it is not NULL, pTerm is a term that provides an upper or lower
+** bound on a range scan. Without considering pTerm, it is estimated
+** that the scan will visit nNew rows. This function returns the number
+** estimated to be visited after taking pTerm into account.
+**
+** If the user explicitly specified a likelihood() value for this term,
+** then the return value is the likelihood multiplied by the number of
+** input rows. Otherwise, this function assumes that an "IS NOT NULL" term
+** has a likelihood of 0.50, and any other term a likelihood of 0.25.
+*/
+static LogEst whereRangeAdjust(WhereTerm *pTerm, LogEst nNew){
+  LogEst nRet = nNew;
+  if( pTerm ){
+    if( pTerm->truthProb<=0 ){
+      nRet += pTerm->truthProb;
+    }else if( (pTerm->wtFlags & TERM_VNULL)==0 ){
+      nRet -= 20;        assert( 20==sqlite3LogEst(4) );
+    }
+  }
+  return nRet;
+}
+
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Return the affinity for a single column of an index.
+*/
+SQLITE_PRIVATE char sqlite3IndexColumnAffinity(sqlite3 *db, Index *pIdx, int iCol){
+  assert( iCol>=0 && iCol<pIdx->nColumn );
+  if( !pIdx->zColAff ){
+    if( sqlite3IndexAffinityStr(db, pIdx)==0 ) return SQLITE_AFF_BLOB;
+  }
+  assert( pIdx->zColAff[iCol]!=0 );
+  return pIdx->zColAff[iCol];
+}
+#endif
+
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** This function is called to estimate the number of rows visited by a
+** range-scan on a skip-scan index. For example:
+**
+**   CREATE INDEX i1 ON t1(a, b, c);
+**   SELECT * FROM t1 WHERE a=? AND c BETWEEN ? AND ?;
+**
+** Value pLoop->nOut is currently set to the estimated number of rows
+** visited for scanning (a=? AND b=?). This function reduces that estimate
+** by some factor to account for the (c BETWEEN ? AND ?) expression based
+** on the stat4 data for the index. this scan will be performed multiple
+** times (once for each (a,b) combination that matches a=?) is dealt with
+** by the caller.
+**
+** It does this by scanning through all stat4 samples, comparing values
+** extracted from pLower and pUpper with the corresponding column in each
+** sample. If L and U are the number of samples found to be less than or
+** equal to the values extracted from pLower and pUpper respectively, and
+** N is the total number of samples, the pLoop->nOut value is adjusted
+** as follows:
+**
+**   nOut = nOut * ( min(U - L, 1) / N )
+**
+** If pLower is NULL, or a value cannot be extracted from the term, L is
+** set to zero. If pUpper is NULL, or a value cannot be extracted from it,
+** U is set to N.
+**
+** Normally, this function sets *pbDone to 1 before returning. However,
+** if no value can be extracted from either pLower or pUpper (and so the
+** estimate of the number of rows delivered remains unchanged), *pbDone
+** is left as is.
+**
+** If an error occurs, an SQLite error code is returned. Otherwise,
+** SQLITE_OK.
+*/
+static int whereRangeSkipScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  WhereTerm *pLower,   /* Lower bound on the range. ex: "x>123" Might be NULL */
+  WhereTerm *pUpper,   /* Upper bound on the range. ex: "x<455" Might be NULL */
+  WhereLoop *pLoop,    /* Update the .nOut value of this loop */
+  int *pbDone          /* Set to true if at least one expr. value extracted */
+){
+  Index *p = pLoop->u.btree.pIndex;
+  int nEq = pLoop->u.btree.nEq;
+  sqlite3 *db = pParse->db;
+  int nLower = -1;
+  int nUpper = p->nSample+1;
+  int rc = SQLITE_OK;
+  u8 aff = sqlite3IndexColumnAffinity(db, p, nEq);
+  CollSeq *pColl;
+
+  sqlite3_value *p1 = 0;          /* Value extracted from pLower */
+  sqlite3_value *p2 = 0;          /* Value extracted from pUpper */
+  sqlite3_value *pVal = 0;        /* Value extracted from record */
+
+  pColl = sqlite3LocateCollSeq(pParse, p->azColl[nEq]);
+  if( pLower ){
+    rc = sqlite3Stat4ValueFromExpr(pParse, pLower->pExpr->pRight, aff, &p1);
+    nLower = 0;
+  }
+  if( pUpper && rc==SQLITE_OK ){
+    rc = sqlite3Stat4ValueFromExpr(pParse, pUpper->pExpr->pRight, aff, &p2);
+    nUpper = p2 ? 0 : p->nSample;
+  }
+
+  if( p1 || p2 ){
+    int i;
+    int nDiff;
+    for(i=0; rc==SQLITE_OK && i<p->nSample; i++){
+      rc = sqlite3Stat4Column(db, p->aSample[i].p, p->aSample[i].n, nEq, &pVal);
+      if( rc==SQLITE_OK && p1 ){
+        int res = sqlite3MemCompare(p1, pVal, pColl);
+        if( res>=0 ) nLower++;
+      }
+      if( rc==SQLITE_OK && p2 ){
+        int res = sqlite3MemCompare(p2, pVal, pColl);
+        if( res>=0 ) nUpper++;
+      }
+    }
+    nDiff = (nUpper - nLower);
+    if( nDiff<=0 ) nDiff = 1;
+
+    /* If there is both an upper and lower bound specified, and the
+    ** comparisons indicate that they are close together, use the fallback
+    ** method (assume that the scan visits 1/64 of the rows) for estimating
+    ** the number of rows visited. Otherwise, estimate the number of rows
+    ** using the method described in the header comment for this function. */
+    if( nDiff!=1 || pUpper==0 || pLower==0 ){
+      int nAdjust = (sqlite3LogEst(p->nSample) - sqlite3LogEst(nDiff));
+      pLoop->nOut -= nAdjust;
+      *pbDone = 1;
+      WHERETRACE(0x20, ("range skip-scan regions: %u..%u  adjust=%d est=%d\n",
+                           nLower, nUpper, nAdjust*-1, pLoop->nOut));
+    }
+
+  }else{
+    assert( *pbDone==0 );
+  }
+
+  sqlite3ValueFree(p1);
+  sqlite3ValueFree(p2);
+  sqlite3ValueFree(pVal);
+
+  return rc;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+/*
+** This function is used to estimate the number of rows that will be visited
+** by scanning an index for a range of values. The range may have an upper
+** bound, a lower bound, or both. The WHERE clause terms that set the upper
+** and lower bounds are represented by pLower and pUpper respectively. For
+** example, assuming that index p is on t1(a):
+**
+**   ... FROM t1 WHERE a > ? AND a < ? ...
+**                    |_____|   |_____|
+**                       |         |
+**                     pLower    pUpper
+**
+** If either of the upper or lower bound is not present, then NULL is passed in
+** place of the corresponding WhereTerm.
+**
+** The value in (pBuilder->pNew->u.btree.nEq) is the number of the index
+** column subject to the range constraint. Or, equivalently, the number of
+** equality constraints optimized by the proposed index scan. For example,
+** assuming index p is on t1(a, b), and the SQL query is:
+**
+**   ... FROM t1 WHERE a = ? AND b > ? AND b < ? ...
+**
+** then nEq is set to 1 (as the range restricted column, b, is the second
+** left-most column of the index). Or, if the query is:
+**
+**   ... FROM t1 WHERE a > ? AND a < ? ...
+**
+** then nEq is set to 0.
+**
+** When this function is called, *pnOut is set to the sqlite3LogEst() of the
+** number of rows that the index scan is expected to visit without
+** considering the range constraints. If nEq is 0, then *pnOut is the number of
+** rows in the index. Assuming no error occurs, *pnOut is adjusted (reduced)
+** to account for the range constraints pLower and pUpper.
+**
+** In the absence of sqlite_stat4 ANALYZE data, or if such data cannot be
+** used, a single range inequality reduces the search space by a factor of 4.
+** and a pair of constraints (x>? AND x<?) reduces the expected number of
+** rows visited by a factor of 64.
+*/
+static int whereRangeScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  WhereLoopBuilder *pBuilder,
+  WhereTerm *pLower,   /* Lower bound on the range. ex: "x>123" Might be NULL */
+  WhereTerm *pUpper,   /* Upper bound on the range. ex: "x<455" Might be NULL */
+  WhereLoop *pLoop     /* Modify the .nOut and maybe .rRun fields */
+){
+  int rc = SQLITE_OK;
+  int nOut = pLoop->nOut;
+  LogEst nNew;
+
+#ifdef SQLITE_ENABLE_STAT4
+  Index *p = pLoop->u.btree.pIndex;
+  int nEq = pLoop->u.btree.nEq;
+
+  if( p->nSample>0 && ALWAYS(nEq<p->nSampleCol)
+   && OptimizationEnabled(pParse->db, SQLITE_Stat4)
+  ){
+    if( nEq==pBuilder->nRecValid ){
+      UnpackedRecord *pRec = pBuilder->pRec;
+      tRowcnt a[2];
+      int nBtm = pLoop->u.btree.nBtm;
+      int nTop = pLoop->u.btree.nTop;
+
+      /* Variable iLower will be set to the estimate of the number of rows in
+      ** the index that are less than the lower bound of the range query. The
+      ** lower bound being the concatenation of $P and $L, where $P is the
+      ** key-prefix formed by the nEq values matched against the nEq left-most
+      ** columns of the index, and $L is the value in pLower.
+      **
+      ** Or, if pLower is NULL or $L cannot be extracted from it (because it
+      ** is not a simple variable or literal value), the lower bound of the
+      ** range is $P. Due to a quirk in the way whereKeyStats() works, even
+      ** if $L is available, whereKeyStats() is called for both ($P) and
+      ** ($P:$L) and the larger of the two returned values is used.
+      **
+      ** Similarly, iUpper is to be set to the estimate of the number of rows
+      ** less than the upper bound of the range query. Where the upper bound
+      ** is either ($P) or ($P:$U). Again, even if $U is available, both values
+      ** of iUpper are requested of whereKeyStats() and the smaller used.
+      **
+      ** The number of rows between the two bounds is then just iUpper-iLower.
+      */
+      tRowcnt iLower;     /* Rows less than the lower bound */
+      tRowcnt iUpper;     /* Rows less than the upper bound */
+      int iLwrIdx = -2;   /* aSample[] for the lower bound */
+      int iUprIdx = -1;   /* aSample[] for the upper bound */
+
+      if( pRec ){
+        testcase( pRec->nField!=pBuilder->nRecValid );
+        pRec->nField = pBuilder->nRecValid;
+      }
+      /* Determine iLower and iUpper using ($P) only. */
+      if( nEq==0 ){
+        iLower = 0;
+        iUpper = p->nRowEst0;
+      }else{
+        /* Note: this call could be optimized away - since the same values must
+        ** have been requested when testing key $P in whereEqualScanEst().  */
+        whereKeyStats(pParse, p, pRec, 0, a);
+        iLower = a[0];
+        iUpper = a[0] + a[1];
+      }
+
+      assert( pLower==0 || (pLower->eOperator & (WO_GT|WO_GE))!=0 );
+      assert( pUpper==0 || (pUpper->eOperator & (WO_LT|WO_LE))!=0 );
+      assert( p->aSortOrder!=0 );
+      if( p->aSortOrder[nEq] ){
+        /* The roles of pLower and pUpper are swapped for a DESC index */
+        SWAP(WhereTerm*, pLower, pUpper);
+        SWAP(int, nBtm, nTop);
+      }
+
+      /* If possible, improve on the iLower estimate using ($P:$L). */
+      if( pLower ){
+        int n;                    /* Values extracted from pExpr */
+        Expr *pExpr = pLower->pExpr->pRight;
+        rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, nBtm, nEq, &n);
+        if( rc==SQLITE_OK && n ){
+          tRowcnt iNew;
+          u16 mask = WO_GT|WO_LE;
+          if( sqlite3ExprVectorSize(pExpr)>n ) mask = (WO_LE|WO_LT);
+          iLwrIdx = whereKeyStats(pParse, p, pRec, 0, a);
+          iNew = a[0] + ((pLower->eOperator & mask) ? a[1] : 0);
+          if( iNew>iLower ) iLower = iNew;
+          nOut--;
+          pLower = 0;
+        }
+      }
+
+      /* If possible, improve on the iUpper estimate using ($P:$U). */
+      if( pUpper ){
+        int n;                    /* Values extracted from pExpr */
+        Expr *pExpr = pUpper->pExpr->pRight;
+        rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, nTop, nEq, &n);
+        if( rc==SQLITE_OK && n ){
+          tRowcnt iNew;
+          u16 mask = WO_GT|WO_LE;
+          if( sqlite3ExprVectorSize(pExpr)>n ) mask = (WO_LE|WO_LT);
+          iUprIdx = whereKeyStats(pParse, p, pRec, 1, a);
+          iNew = a[0] + ((pUpper->eOperator & mask) ? a[1] : 0);
+          if( iNew<iUpper ) iUpper = iNew;
+          nOut--;
+          pUpper = 0;
+        }
+      }
+
+      pBuilder->pRec = pRec;
+      if( rc==SQLITE_OK ){
+        if( iUpper>iLower ){
+          nNew = sqlite3LogEst(iUpper - iLower);
+          /* TUNING:  If both iUpper and iLower are derived from the same
+          ** sample, then assume they are 4x more selective.  This brings
+          ** the estimated selectivity more in line with what it would be
+          ** if estimated without the use of STAT4 tables. */
+          if( iLwrIdx==iUprIdx ){ nNew -= 20; }
+          assert( 20==sqlite3LogEst(4) );
+        }else{
+          nNew = 10;        assert( 10==sqlite3LogEst(2) );
+        }
+        if( nNew<nOut ){
+          nOut = nNew;
+        }
+        WHERETRACE(0x20, ("STAT4 range scan: %u..%u  est=%d\n",
+                           (u32)iLower, (u32)iUpper, nOut));
+      }
+    }else{
+      int bDone = 0;
+      rc = whereRangeSkipScanEst(pParse, pLower, pUpper, pLoop, &bDone);
+      if( bDone ) return rc;
+    }
+  }
+#else
+  UNUSED_PARAMETER(pParse);
+  UNUSED_PARAMETER(pBuilder);
+  assert( pLower || pUpper );
+#endif
+  assert( pUpper==0 || (pUpper->wtFlags & TERM_VNULL)==0 || pParse->nErr>0 );
+  nNew = whereRangeAdjust(pLower, nOut);
+  nNew = whereRangeAdjust(pUpper, nNew);
+
+  /* TUNING: If there is both an upper and lower limit and neither limit
+  ** has an application-defined likelihood(), assume the range is
+  ** reduced by an additional 75%. This means that, by default, an open-ended
+  ** range query (e.g. col > ?) is assumed to match 1/4 of the rows in the
+  ** index. While a closed range (e.g. col BETWEEN ? AND ?) is estimated to
+  ** match 1/64 of the index. */
+  if( pLower && pLower->truthProb>0 && pUpper && pUpper->truthProb>0 ){
+    nNew -= 20;
+  }
+
+  nOut -= (pLower!=0) + (pUpper!=0);
+  if( nNew<10 ) nNew = 10;
+  if( nNew<nOut ) nOut = nNew;
+#if defined(WHERETRACE_ENABLED)
+  if( pLoop->nOut>nOut ){
+    WHERETRACE(0x20,("Range scan lowers nOut from %d to %d\n",
+                    pLoop->nOut, nOut));
+  }
+#endif
+  pLoop->nOut = (LogEst)nOut;
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Estimate the number of rows that will be returned based on
+** an equality constraint x=VALUE and where that VALUE occurs in
+** the histogram data.  This only works when x is the left-most
+** column of an index and sqlite_stat4 histogram data is available
+** for that index.  When pExpr==NULL that means the constraint is
+** "x IS NULL" instead of "x=VALUE".
+**
+** Write the estimated row count into *pnRow and return SQLITE_OK.
+** If unable to make an estimate, leave *pnRow unchanged and return
+** non-zero.
+**
+** This routine can fail if it is unable to load a collating sequence
+** required for string comparison, or if unable to allocate memory
+** for a UTF conversion required for comparison.  The error is stored
+** in the pParse structure.
+*/
+static int whereEqualScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  WhereLoopBuilder *pBuilder,
+  Expr *pExpr,         /* Expression for VALUE in the x=VALUE constraint */
+  tRowcnt *pnRow       /* Write the revised row estimate here */
+){
+  Index *p = pBuilder->pNew->u.btree.pIndex;
+  int nEq = pBuilder->pNew->u.btree.nEq;
+  UnpackedRecord *pRec = pBuilder->pRec;
+  int rc;                   /* Subfunction return code */
+  tRowcnt a[2];             /* Statistics */
+  int bOk;
+
+  assert( nEq>=1 );
+  assert( nEq<=p->nColumn );
+  assert( p->aSample!=0 );
+  assert( p->nSample>0 );
+  assert( pBuilder->nRecValid<nEq );
+
+  /* If values are not available for all fields of the index to the left
+  ** of this one, no estimate can be made. Return SQLITE_NOTFOUND. */
+  if( pBuilder->nRecValid<(nEq-1) ){
+    return SQLITE_NOTFOUND;
+  }
+
+  /* This is an optimization only. The call to sqlite3Stat4ProbeSetValue()
+  ** below would return the same value.  */
+  if( nEq>=p->nColumn ){
+    *pnRow = 1;
+    return SQLITE_OK;
+  }
+
+  rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, 1, nEq-1, &bOk);
+  pBuilder->pRec = pRec;
+  if( rc!=SQLITE_OK ) return rc;
+  if( bOk==0 ) return SQLITE_NOTFOUND;
+  pBuilder->nRecValid = nEq;
+
+  whereKeyStats(pParse, p, pRec, 0, a);
+  WHERETRACE(0x20,("equality scan regions %s(%d): %d\n",
+                   p->zName, nEq-1, (int)a[1]));
+  *pnRow = a[1];
+
+  return rc;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Estimate the number of rows that will be returned based on
+** an IN constraint where the right-hand side of the IN operator
+** is a list of values.  Example:
+**
+**        WHERE x IN (1,2,3,4)
+**
+** Write the estimated row count into *pnRow and return SQLITE_OK.
+** If unable to make an estimate, leave *pnRow unchanged and return
+** non-zero.
+**
+** This routine can fail if it is unable to load a collating sequence
+** required for string comparison, or if unable to allocate memory
+** for a UTF conversion required for comparison.  The error is stored
+** in the pParse structure.
+*/
+static int whereInScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  WhereLoopBuilder *pBuilder,
+  ExprList *pList,     /* The value list on the RHS of "x IN (v1,v2,v3,...)" */
+  tRowcnt *pnRow       /* Write the revised row estimate here */
+){
+  Index *p = pBuilder->pNew->u.btree.pIndex;
+  i64 nRow0 = sqlite3LogEstToInt(p->aiRowLogEst[0]);
+  int nRecValid = pBuilder->nRecValid;
+  int rc = SQLITE_OK;     /* Subfunction return code */
+  tRowcnt nEst;           /* Number of rows for a single term */
+  tRowcnt nRowEst = 0;    /* New estimate of the number of rows */
+  int i;                  /* Loop counter */
+
+  assert( p->aSample!=0 );
+  for(i=0; rc==SQLITE_OK && i<pList->nExpr; i++){
+    nEst = nRow0;
+    rc = whereEqualScanEst(pParse, pBuilder, pList->a[i].pExpr, &nEst);
+    nRowEst += nEst;
+    pBuilder->nRecValid = nRecValid;
+  }
+
+  if( rc==SQLITE_OK ){
+    if( nRowEst > (tRowcnt)nRow0 ) nRowEst = nRow0;
+    *pnRow = nRowEst;
+    WHERETRACE(0x20,("IN row estimate: est=%d\n", nRowEst));
+  }
+  assert( pBuilder->nRecValid==nRecValid );
+  return rc;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+
+#if defined(WHERETRACE_ENABLED) || defined(SQLITE_DEBUG)
+/*
+** Print the content of a WhereTerm object
+*/
+SQLITE_PRIVATE void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm){
+  if( pTerm==0 ){
+    sqlite3DebugPrintf("TERM-%-3d NULL\n", iTerm);
+  }else{
+    char zType[8];
+    char zLeft[50];
+    memcpy(zType, "....", 5);
+    if( pTerm->wtFlags & TERM_VIRTUAL ) zType[0] = 'V';
+    if( pTerm->eOperator & WO_EQUIV  ) zType[1] = 'E';
+    if( ExprHasProperty(pTerm->pExpr, EP_OuterON) ) zType[2] = 'L';
+    if( pTerm->wtFlags & TERM_CODED  ) zType[3] = 'C';
+    if( pTerm->eOperator & WO_SINGLE ){
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      sqlite3_snprintf(sizeof(zLeft),zLeft,"left={%d:%d}",
+                       pTerm->leftCursor, pTerm->u.x.leftColumn);
+    }else if( (pTerm->eOperator & WO_OR)!=0 && pTerm->u.pOrInfo!=0 ){
+      sqlite3_snprintf(sizeof(zLeft),zLeft,"indexable=0x%llx",
+                       pTerm->u.pOrInfo->indexable);
+    }else{
+      sqlite3_snprintf(sizeof(zLeft),zLeft,"left=%d", pTerm->leftCursor);
+    }
+    sqlite3DebugPrintf(
+       "TERM-%-3d %p %s %-12s op=%03x wtFlags=%04x",
+       iTerm, pTerm, zType, zLeft, pTerm->eOperator, pTerm->wtFlags);
+    /* The 0x10000 .wheretrace flag causes extra information to be
+    ** shown about each Term */
+    if( sqlite3WhereTrace & 0x10000 ){
+      sqlite3DebugPrintf(" prob=%-3d prereq=%llx,%llx",
+        pTerm->truthProb, (u64)pTerm->prereqAll, (u64)pTerm->prereqRight);
+    }
+    if( (pTerm->eOperator & (WO_OR|WO_AND))==0 && pTerm->u.x.iField ){
+      sqlite3DebugPrintf(" iField=%d", pTerm->u.x.iField);
+    }
+    if( pTerm->iParent>=0 ){
+      sqlite3DebugPrintf(" iParent=%d", pTerm->iParent);
+    }
+    sqlite3DebugPrintf("\n");
+    sqlite3TreeViewExpr(0, pTerm->pExpr, 0);
+  }
+}
+SQLITE_PRIVATE void sqlite3ShowWhereTerm(WhereTerm *pTerm){
+  sqlite3WhereTermPrint(pTerm, 0);
+}
+#endif
+
+#ifdef WHERETRACE_ENABLED
+/*
+** Show the complete content of a WhereClause
+*/
+SQLITE_PRIVATE void sqlite3WhereClausePrint(WhereClause *pWC){
+  int i;
+  for(i=0; i<pWC->nTerm; i++){
+    sqlite3WhereTermPrint(&pWC->a[i], i);
+  }
+}
+#endif
+
+#ifdef WHERETRACE_ENABLED
+/*
+** Print a WhereLoop object for debugging purposes
+**
+** Format example:
+**
+**     .--- Position in WHERE clause           rSetup, rRun, nOut ---.
+**     |                                                             |
+**     |  .--- selfMask                       nTerm ------.          |
+**     |  |                                               |          |
+**     |  |   .-- prereq    Idx          wsFlags----.     |          |
+**     |  |   |             Name                    |     |          |
+**     |  |   |           __|__        nEq ---.  ___|__   |        __|__
+**     | / \ / \         /     \              | /      \ / \      /     \
+**     1.002.001         t2.t2xy              2 f 010241 N 2 cost 0,56,31
+*/
+SQLITE_PRIVATE void sqlite3WhereLoopPrint(const WhereLoop *p, const WhereClause *pWC){
+  WhereInfo *pWInfo;
+  if( pWC ){
+    pWInfo = pWC->pWInfo;
+    int nb = 1+(pWInfo->pTabList->nSrc+3)/4;
+    SrcItem *pItem = pWInfo->pTabList->a + p->iTab;
+    Table *pTab = pItem->pSTab;
+    Bitmask mAll = (((Bitmask)1)<<(nb*4)) - 1;
+    sqlite3DebugPrintf("%c%2d.%0*llx.%0*llx", p->cId,
+                       p->iTab, nb, p->maskSelf, nb, p->prereq & mAll);
+    sqlite3DebugPrintf(" %12s",
+                       pItem->zAlias ? pItem->zAlias : pTab->zName);
+  }else{
+    pWInfo = 0;
+    sqlite3DebugPrintf("%c%2d.%03llx.%03llx %c%d",
+         p->cId, p->iTab, p->maskSelf, p->prereq & 0xfff, p->cId, p->iTab);
+  }
+  if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
+    const char *zName;
+    if( p->u.btree.pIndex && (zName = p->u.btree.pIndex->zName)!=0 ){
+      if( strncmp(zName, "sqlite_autoindex_", 17)==0 ){
+        int i = sqlite3Strlen30(zName) - 1;
+        while( zName[i]!='_' ) i--;
+        zName += i;
+      }
+      sqlite3DebugPrintf(".%-16s %2d", zName, p->u.btree.nEq);
+    }else{
+      sqlite3DebugPrintf("%20s","");
+    }
+  }else{
+    char *z;
+    if( p->u.vtab.idxStr ){
+      z = sqlite3_mprintf("(%d,\"%s\",%#x)",
+                p->u.vtab.idxNum, p->u.vtab.idxStr, p->u.vtab.omitMask);
+    }else{
+      z = sqlite3_mprintf("(%d,%x)", p->u.vtab.idxNum, p->u.vtab.omitMask);
+    }
+    sqlite3DebugPrintf(" %-19s", z);
+    sqlite3_free(z);
+  }
+  if( p->wsFlags & WHERE_SKIPSCAN ){
+    sqlite3DebugPrintf(" f %06x %d-%d", p->wsFlags, p->nLTerm,p->nSkip);
+  }else{
+    sqlite3DebugPrintf(" f %06x N %d", p->wsFlags, p->nLTerm);
+  }
+  if( pWInfo && pWInfo->bStarUsed && p->rStarDelta!=0 ){
+    sqlite3DebugPrintf(" cost %d,%d,%d delta=%d\n",
+                       p->rSetup, p->rRun, p->nOut, p->rStarDelta);
+  }else{
+    sqlite3DebugPrintf(" cost %d,%d,%d\n", p->rSetup, p->rRun, p->nOut);
+  }
+  if( p->nLTerm && (sqlite3WhereTrace & 0x4000)!=0 ){
+    int i;
+    for(i=0; i<p->nLTerm; i++){
+      sqlite3WhereTermPrint(p->aLTerm[i], i);
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3ShowWhereLoop(const WhereLoop *p){
+  if( p ) sqlite3WhereLoopPrint(p, 0);
+}
+SQLITE_PRIVATE void sqlite3ShowWhereLoopList(const WhereLoop *p){
+  while( p ){
+    sqlite3ShowWhereLoop(p);
+    p = p->pNextLoop;
+  }
+}
+#endif
+
+/*
+** Convert bulk memory into a valid WhereLoop that can be passed
+** to whereLoopClear harmlessly.
+*/
+static void whereLoopInit(WhereLoop *p){
+  p->aLTerm = p->aLTermSpace;
+  p->nLTerm = 0;
+  p->nLSlot = ArraySize(p->aLTermSpace);
+  p->wsFlags = 0;
+}
+
+/*
+** Clear the WhereLoop.u union.  Leave WhereLoop.pLTerm intact.
+*/
+static void whereLoopClearUnion(sqlite3 *db, WhereLoop *p){
+  if( p->wsFlags & (WHERE_VIRTUALTABLE|WHERE_AUTO_INDEX) ){
+    if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 && p->u.vtab.needFree ){
+      sqlite3_free(p->u.vtab.idxStr);
+      p->u.vtab.needFree = 0;
+      p->u.vtab.idxStr = 0;
+    }else if( (p->wsFlags & WHERE_AUTO_INDEX)!=0 && p->u.btree.pIndex!=0 ){
+      sqlite3DbFree(db, p->u.btree.pIndex->zColAff);
+      sqlite3DbFreeNN(db, p->u.btree.pIndex);
+      p->u.btree.pIndex = 0;
+    }
+  }
+}
+
+/*
+** Deallocate internal memory used by a WhereLoop object.  Leave the
+** object in an initialized state, as if it had been newly allocated.
+*/
+static void whereLoopClear(sqlite3 *db, WhereLoop *p){
+  if( p->aLTerm!=p->aLTermSpace ){
+    sqlite3DbFreeNN(db, p->aLTerm);
+    p->aLTerm = p->aLTermSpace;
+    p->nLSlot = ArraySize(p->aLTermSpace);
+  }
+  whereLoopClearUnion(db, p);
+  p->nLTerm = 0;
+  p->wsFlags = 0;
+}
+
+/*
+** Increase the memory allocation for pLoop->aLTerm[] to be at least n.
+*/
+static int whereLoopResize(sqlite3 *db, WhereLoop *p, int n){
+  WhereTerm **paNew;
+  if( p->nLSlot>=n ) return SQLITE_OK;
+  n = (n+7)&~7;
+  paNew = sqlite3DbMallocRawNN(db, sizeof(p->aLTerm[0])*n);
+  if( paNew==0 ) return SQLITE_NOMEM_BKPT;
+  memcpy(paNew, p->aLTerm, sizeof(p->aLTerm[0])*p->nLSlot);
+  if( p->aLTerm!=p->aLTermSpace ) sqlite3DbFreeNN(db, p->aLTerm);
+  p->aLTerm = paNew;
+  p->nLSlot = n;
+  return SQLITE_OK;
+}
+
+/*
+** Transfer content from the second pLoop into the first.
+*/
+static int whereLoopXfer(sqlite3 *db, WhereLoop *pTo, WhereLoop *pFrom){
+  whereLoopClearUnion(db, pTo);
+  if( pFrom->nLTerm > pTo->nLSlot
+   && whereLoopResize(db, pTo, pFrom->nLTerm)
+  ){
+    memset(pTo, 0, WHERE_LOOP_XFER_SZ);
+    return SQLITE_NOMEM_BKPT;
+  }
+  memcpy(pTo, pFrom, WHERE_LOOP_XFER_SZ);
+  memcpy(pTo->aLTerm, pFrom->aLTerm, pTo->nLTerm*sizeof(pTo->aLTerm[0]));
+  if( pFrom->wsFlags & WHERE_VIRTUALTABLE ){
+    pFrom->u.vtab.needFree = 0;
+  }else if( (pFrom->wsFlags & WHERE_AUTO_INDEX)!=0 ){
+    pFrom->u.btree.pIndex = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Delete a WhereLoop object
+*/
+static void whereLoopDelete(sqlite3 *db, WhereLoop *p){
+  assert( db!=0 );
+  whereLoopClear(db, p);
+  sqlite3DbNNFreeNN(db, p);
+}
+
+/*
+** Free a WhereInfo structure
+*/
+static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
+  assert( pWInfo!=0 );
+  assert( db!=0 );
+  sqlite3WhereClauseClear(&pWInfo->sWC);
+  while( pWInfo->pLoops ){
+    WhereLoop *p = pWInfo->pLoops;
+    pWInfo->pLoops = p->pNextLoop;
+    whereLoopDelete(db, p);
+  }
+  while( pWInfo->pMemToFree ){
+    WhereMemBlock *pNext = pWInfo->pMemToFree->pNext;
+    sqlite3DbNNFreeNN(db, pWInfo->pMemToFree);
+    pWInfo->pMemToFree = pNext;
+  }
+  sqlite3DbNNFreeNN(db, pWInfo);
+}
+
+/*
+** Return TRUE if X is a proper subset of Y but is of equal or less cost.
+** In other words, return true if all constraints of X are also part of Y
+** and Y has additional constraints that might speed the search that X lacks
+** but the cost of running X is not more than the cost of running Y.
+**
+** In other words, return true if the cost relationship between X and Y
+** is inverted and needs to be adjusted.
+**
+** Case 1:
+**
+**   (1a)  X and Y use the same index.
+**   (1b)  X has fewer == terms than Y
+**   (1c)  Neither X nor Y use skip-scan
+**   (1d)  X does not have a a greater cost than Y
+**
+** Case 2:
+**
+**   (2a)  X has the same or lower cost, or returns the same or fewer rows,
+**         than Y.
+**   (2b)  X uses fewer WHERE clause terms than Y
+**   (2c)  Every WHERE clause term used by X is also used by Y
+**   (2d)  X skips at least as many columns as Y
+**   (2e)  If X is a covering index, than Y is too
+*/
+static int whereLoopCheaperProperSubset(
+  const WhereLoop *pX,       /* First WhereLoop to compare */
+  const WhereLoop *pY        /* Compare against this WhereLoop */
+){
+  int i, j;
+  if( pX->rRun>pY->rRun && pX->nOut>pY->nOut ) return 0; /* (1d) and (2a) */
+  assert( (pX->wsFlags & WHERE_VIRTUALTABLE)==0 );
+  assert( (pY->wsFlags & WHERE_VIRTUALTABLE)==0 );
+  if( pX->u.btree.nEq < pY->u.btree.nEq                  /* (1b) */
+   && pX->u.btree.pIndex==pY->u.btree.pIndex             /* (1a) */
+   && pX->nSkip==0 && pY->nSkip==0                       /* (1c) */
+  ){
+    return 1;  /* Case 1 is true */
+  }
+  if( pX->nLTerm-pX->nSkip >= pY->nLTerm-pY->nSkip ){
+    return 0;                                            /* (2b) */
+  }
+  if( pY->nSkip > pX->nSkip ) return 0;                  /* (2d) */
+  for(i=pX->nLTerm-1; i>=0; i--){
+    if( pX->aLTerm[i]==0 ) continue;
+    for(j=pY->nLTerm-1; j>=0; j--){
+      if( pY->aLTerm[j]==pX->aLTerm[i] ) break;
+    }
+    if( j<0 ) return 0;                                  /* (2c) */
+  }
+  if( (pX->wsFlags&WHERE_IDX_ONLY)!=0
+   && (pY->wsFlags&WHERE_IDX_ONLY)==0 ){
+    return 0;                                            /* (2e) */
+  }
+  return 1;  /* Case 2 is true */
+}
+
+/*
+** Try to adjust the cost and number of output rows of WhereLoop pTemplate
+** upwards or downwards so that:
+**
+**   (1) pTemplate costs less than any other WhereLoops that are a proper
+**       subset of pTemplate
+**
+**   (2) pTemplate costs more than any other WhereLoops for which pTemplate
+**       is a proper subset.
+**
+** To say "WhereLoop X is a proper subset of Y" means that X uses fewer
+** WHERE clause terms than Y and that every WHERE clause term used by X is
+** also used by Y.
+*/
+static void whereLoopAdjustCost(const WhereLoop *p, WhereLoop *pTemplate){
+  if( (pTemplate->wsFlags & WHERE_INDEXED)==0 ) return;
+  for(; p; p=p->pNextLoop){
+    if( p->iTab!=pTemplate->iTab ) continue;
+    if( (p->wsFlags & WHERE_INDEXED)==0 ) continue;
+    if( whereLoopCheaperProperSubset(p, pTemplate) ){
+      /* Adjust pTemplate cost downward so that it is cheaper than its
+      ** subset p. */
+      WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n",
+                       pTemplate->rRun, pTemplate->nOut,
+                       MIN(p->rRun, pTemplate->rRun),
+                       MIN(p->nOut - 1, pTemplate->nOut)));
+      pTemplate->rRun = MIN(p->rRun, pTemplate->rRun);
+      pTemplate->nOut = MIN(p->nOut - 1, pTemplate->nOut);
+    }else if( whereLoopCheaperProperSubset(pTemplate, p) ){
+      /* Adjust pTemplate cost upward so that it is costlier than p since
+      ** pTemplate is a proper subset of p */
+      WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n",
+                       pTemplate->rRun, pTemplate->nOut,
+                       MAX(p->rRun, pTemplate->rRun),
+                       MAX(p->nOut + 1, pTemplate->nOut)));
+      pTemplate->rRun = MAX(p->rRun, pTemplate->rRun);
+      pTemplate->nOut = MAX(p->nOut + 1, pTemplate->nOut);
+    }
+  }
+}
+
+/*
+** Search the list of WhereLoops in *ppPrev looking for one that can be
+** replaced by pTemplate.
+**
+** Return NULL if pTemplate does not belong on the WhereLoop list.
+** In other words if pTemplate ought to be dropped from further consideration.
+**
+** If pX is a WhereLoop that pTemplate can replace, then return the
+** link that points to pX.
+**
+** If pTemplate cannot replace any existing element of the list but needs
+** to be added to the list as a new entry, then return a pointer to the
+** tail of the list.
+*/
+static WhereLoop **whereLoopFindLesser(
+  WhereLoop **ppPrev,
+  const WhereLoop *pTemplate
+){
+  WhereLoop *p;
+  for(p=(*ppPrev); p; ppPrev=&p->pNextLoop, p=*ppPrev){
+    if( p->iTab!=pTemplate->iTab || p->iSortIdx!=pTemplate->iSortIdx ){
+      /* If either the iTab or iSortIdx values for two WhereLoop are different
+      ** then those WhereLoops need to be considered separately.  Neither is
+      ** a candidate to replace the other. */
+      continue;
+    }
+    /* In the current implementation, the rSetup value is either zero
+    ** or the cost of building an automatic index (NlogN) and the NlogN
+    ** is the same for compatible WhereLoops. */
+    assert( p->rSetup==0 || pTemplate->rSetup==0
+                 || p->rSetup==pTemplate->rSetup );
+
+    /* whereLoopAddBtree() always generates and inserts the automatic index
+    ** case first.  Hence compatible candidate WhereLoops never have a larger
+    ** rSetup. Call this SETUP-INVARIANT */
+    assert( p->rSetup>=pTemplate->rSetup );
+
+    /* Any loop using an application-defined index (or PRIMARY KEY or
+    ** UNIQUE constraint) with one or more == constraints is better
+    ** than an automatic index. Unless it is a skip-scan. */
+    if( (p->wsFlags & WHERE_AUTO_INDEX)!=0
+     && (pTemplate->nSkip)==0
+     && (pTemplate->wsFlags & WHERE_INDEXED)!=0
+     && (pTemplate->wsFlags & WHERE_COLUMN_EQ)!=0
+     && (p->prereq & pTemplate->prereq)==pTemplate->prereq
+    ){
+      break;
+    }
+
+    /* If existing WhereLoop p is better than pTemplate, pTemplate can be
+    ** discarded.  WhereLoop p is better if:
+    **   (1)  p has no more dependencies than pTemplate, and
+    **   (2)  p has an equal or lower cost than pTemplate
+    */
+    if( (p->prereq & pTemplate->prereq)==p->prereq    /* (1)  */
+     && p->rSetup<=pTemplate->rSetup                  /* (2a) */
+     && p->rRun<=pTemplate->rRun                      /* (2b) */
+     && p->nOut<=pTemplate->nOut                      /* (2c) */
+    ){
+      return 0;  /* Discard pTemplate */
+    }
+
+    /* If pTemplate is always better than p, then cause p to be overwritten
+    ** with pTemplate.  pTemplate is better than p if:
+    **   (1)  pTemplate has no more dependencies than p, and
+    **   (2)  pTemplate has an equal or lower cost than p.
+    */
+    if( (p->prereq & pTemplate->prereq)==pTemplate->prereq   /* (1)  */
+     && p->rRun>=pTemplate->rRun                             /* (2a) */
+     && p->nOut>=pTemplate->nOut                             /* (2b) */
+    ){
+      assert( p->rSetup>=pTemplate->rSetup ); /* SETUP-INVARIANT above */
+      break;   /* Cause p to be overwritten by pTemplate */
+    }
+  }
+  return ppPrev;
+}
+
+/*
+** Insert or replace a WhereLoop entry using the template supplied.
+**
+** An existing WhereLoop entry might be overwritten if the new template
+** is better and has fewer dependencies.  Or the template will be ignored
+** and no insert will occur if an existing WhereLoop is faster and has
+** fewer dependencies than the template.  Otherwise a new WhereLoop is
+** added based on the template.
+**
+** If pBuilder->pOrSet is not NULL then we care about only the
+** prerequisites and rRun and nOut costs of the N best loops.  That
+** information is gathered in the pBuilder->pOrSet object.  This special
+** processing mode is used only for OR clause processing.
+**
+** When accumulating multiple loops (when pBuilder->pOrSet is NULL) we
+** still might overwrite similar loops with the new template if the
+** new template is better.  Loops may be overwritten if the following
+** conditions are met:
+**
+**    (1)  They have the same iTab.
+**    (2)  They have the same iSortIdx.
+**    (3)  The template has same or fewer dependencies than the current loop
+**    (4)  The template has the same or lower cost than the current loop
+*/
+static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
+  WhereLoop **ppPrev, *p;
+  WhereInfo *pWInfo = pBuilder->pWInfo;
+  sqlite3 *db = pWInfo->pParse->db;
+  int rc;
+
+  /* Stop the search once we hit the query planner search limit */
+  if( pBuilder->iPlanLimit==0 ){
+    WHERETRACE(0xffffffff,("=== query planner search limit reached ===\n"));
+    if( pBuilder->pOrSet ) pBuilder->pOrSet->n = 0;
+    return SQLITE_DONE;
+  }
+  pBuilder->iPlanLimit--;
+
+  whereLoopAdjustCost(pWInfo->pLoops, pTemplate);
+
+  /* If pBuilder->pOrSet is defined, then only keep track of the costs
+  ** and prereqs.
+  */
+  if( pBuilder->pOrSet!=0 ){
+    if( pTemplate->nLTerm ){
+#if WHERETRACE_ENABLED
+      u16 n = pBuilder->pOrSet->n;
+      int x =
+#endif
+      whereOrInsert(pBuilder->pOrSet, pTemplate->prereq, pTemplate->rRun,
+                                    pTemplate->nOut);
+#if WHERETRACE_ENABLED /* 0x8 */
+      if( sqlite3WhereTrace & 0x8 ){
+        sqlite3DebugPrintf(x?"   or-%d:  ":"   or-X:  ", n);
+        sqlite3WhereLoopPrint(pTemplate, pBuilder->pWC);
+      }
+#endif
+    }
+    return SQLITE_OK;
+  }
+
+  /* Look for an existing WhereLoop to replace with pTemplate
+  */
+  ppPrev = whereLoopFindLesser(&pWInfo->pLoops, pTemplate);
+
+  if( ppPrev==0 ){
+    /* There already exists a WhereLoop on the list that is better
+    ** than pTemplate, so just ignore pTemplate */
+#if WHERETRACE_ENABLED /* 0x8 */
+    if( sqlite3WhereTrace & 0x8 ){
+      sqlite3DebugPrintf("   skip: ");
+      sqlite3WhereLoopPrint(pTemplate, pBuilder->pWC);
+    }
+#endif
+    return SQLITE_OK;
+  }else{
+    p = *ppPrev;
+  }
+
+  /* If we reach this point it means that either p[] should be overwritten
+  ** with pTemplate[] if p[] exists, or if p==NULL then allocate a new
+  ** WhereLoop and insert it.
+  */
+#if WHERETRACE_ENABLED /* 0x8 */
+  if( sqlite3WhereTrace & 0x8 ){
+    if( p!=0 ){
+      sqlite3DebugPrintf("replace: ");
+      sqlite3WhereLoopPrint(p, pBuilder->pWC);
+      sqlite3DebugPrintf("   with: ");
+    }else{
+      sqlite3DebugPrintf("    add: ");
+    }
+    sqlite3WhereLoopPrint(pTemplate, pBuilder->pWC);
+  }
+#endif
+  if( p==0 ){
+    /* Allocate a new WhereLoop to add to the end of the list */
+    *ppPrev = p = sqlite3DbMallocRawNN(db, sizeof(WhereLoop));
+    if( p==0 ) return SQLITE_NOMEM_BKPT;
+    whereLoopInit(p);
+    p->pNextLoop = 0;
+  }else{
+    /* We will be overwriting WhereLoop p[].  But before we do, first
+    ** go through the rest of the list and delete any other entries besides
+    ** p[] that are also supplanted by pTemplate */
+    WhereLoop **ppTail = &p->pNextLoop;
+    WhereLoop *pToDel;
+    while( *ppTail ){
+      ppTail = whereLoopFindLesser(ppTail, pTemplate);
+      if( ppTail==0 ) break;
+      pToDel = *ppTail;
+      if( pToDel==0 ) break;
+      *ppTail = pToDel->pNextLoop;
+#if WHERETRACE_ENABLED /* 0x8 */
+      if( sqlite3WhereTrace & 0x8 ){
+        sqlite3DebugPrintf(" delete: ");
+        sqlite3WhereLoopPrint(pToDel, pBuilder->pWC);
+      }
+#endif
+      whereLoopDelete(db, pToDel);
+    }
+  }
+  rc = whereLoopXfer(db, p, pTemplate);
+  if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
+    Index *pIndex = p->u.btree.pIndex;
+    if( pIndex && pIndex->idxType==SQLITE_IDXTYPE_IPK ){
+      p->u.btree.pIndex = 0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Adjust the WhereLoop.nOut value downward to account for terms of the
+** WHERE clause that reference the loop but which are not used by an
+** index.
+*
+** For every WHERE clause term that is not used by the index
+** and which has a truth probability assigned by one of the likelihood(),
+** likely(), or unlikely() SQL functions, reduce the estimated number
+** of output rows by the probability specified.
+**
+** TUNING:  For every WHERE clause term that is not used by the index
+** and which does not have an assigned truth probability, heuristics
+** described below are used to try to estimate the truth probability.
+** TODO --> Perhaps this is something that could be improved by better
+** table statistics.
+**
+** Heuristic 1:  Estimate the truth probability as 93.75%.  The 93.75%
+** value corresponds to -1 in LogEst notation, so this means decrement
+** the WhereLoop.nOut field for every such WHERE clause term.
+**
+** Heuristic 2:  If there exists one or more WHERE clause terms of the
+** form "x==EXPR" and EXPR is not a constant 0 or 1, then make sure the
+** final output row estimate is no greater than 1/4 of the total number
+** of rows in the table.  In other words, assume that x==EXPR will filter
+** out at least 3 out of 4 rows.  If EXPR is -1 or 0 or 1, then maybe the
+** "x" column is boolean or else -1 or 0 or 1 is a common default value
+** on the "x" column and so in that case only cap the output row estimate
+** at 1/2 instead of 1/4.
+*/
+static void whereLoopOutputAdjust(
+  WhereClause *pWC,      /* The WHERE clause */
+  WhereLoop *pLoop,      /* The loop to adjust downward */
+  LogEst nRow            /* Number of rows in the entire table */
+){
+  WhereTerm *pTerm, *pX;
+  Bitmask notAllowed = ~(pLoop->prereq|pLoop->maskSelf);
+  int i, j;
+  LogEst iReduce = 0;    /* pLoop->nOut should not exceed nRow-iReduce */
+
+  assert( (pLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
+  for(i=pWC->nBase, pTerm=pWC->a; i>0; i--, pTerm++){
+    assert( pTerm!=0 );
+    if( (pTerm->prereqAll & notAllowed)!=0 ) continue;
+    if( (pTerm->prereqAll & pLoop->maskSelf)==0 ) continue;
+    if( (pTerm->wtFlags & TERM_VIRTUAL)!=0 ) continue;
+    for(j=pLoop->nLTerm-1; j>=0; j--){
+      pX = pLoop->aLTerm[j];
+      if( pX==0 ) continue;
+      if( pX==pTerm ) break;
+      if( pX->iParent>=0 && (&pWC->a[pX->iParent])==pTerm ) break;
+    }
+    if( j<0 ){
+      sqlite3ProgressCheck(pWC->pWInfo->pParse);
+      if( pLoop->maskSelf==pTerm->prereqAll ){
+        /* If there are extra terms in the WHERE clause not used by an index
+        ** that depend only on the table being scanned, and that will tend to
+        ** cause many rows to be omitted, then mark that table as
+        ** "self-culling".
+        **
+        ** 2022-03-24:  Self-culling only applies if either the extra terms
+        ** are straight comparison operators that are non-true with NULL
+        ** operand, or if the loop is not an OUTER JOIN.
+        */
+        if( (pTerm->eOperator & 0x3f)!=0
+         || (pWC->pWInfo->pTabList->a[pLoop->iTab].fg.jointype
+                  & (JT_LEFT|JT_LTORJ))==0
+        ){
+          pLoop->wsFlags |= WHERE_SELFCULL;
+        }
+      }
+      if( pTerm->truthProb<=0 ){
+        /* If a truth probability is specified using the likelihood() hints,
+        ** then use the probability provided by the application. */
+        pLoop->nOut += pTerm->truthProb;
+      }else{
+        /* In the absence of explicit truth probabilities, use heuristics to
+        ** guess a reasonable truth probability. */
+        pLoop->nOut--;
+        if( (pTerm->eOperator&(WO_EQ|WO_IS))!=0
+         && (pTerm->wtFlags & TERM_HIGHTRUTH)==0  /* tag-20200224-1 */
+        ){
+          Expr *pRight = pTerm->pExpr->pRight;
+          int k = 0;
+          testcase( pTerm->pExpr->op==TK_IS );
+          if( sqlite3ExprIsInteger(pRight, &k, 0) && k>=(-1) && k<=1 ){
+            k = 10;
+          }else{
+            k = 20;
+          }
+          if( iReduce<k ){
+            pTerm->wtFlags |= TERM_HEURTRUTH;
+            iReduce = k;
+          }
+        }
+      }
+    }
+  }
+  if( pLoop->nOut > nRow-iReduce ){
+    pLoop->nOut = nRow - iReduce;
+  }
+}
+
+/*
+** Term pTerm is a vector range comparison operation. The first comparison
+** in the vector can be optimized using column nEq of the index. This
+** function returns the total number of vector elements that can be used
+** as part of the range comparison.
+**
+** For example, if the query is:
+**
+**   WHERE a = ? AND (b, c, d) > (?, ?, ?)
+**
+** and the index:
+**
+**   CREATE INDEX ... ON (a, b, c, d, e)
+**
+** then this function would be invoked with nEq=1. The value returned in
+** this case is 3.
+*/
+static int whereRangeVectorLen(
+  Parse *pParse,       /* Parsing context */
+  int iCur,            /* Cursor open on pIdx */
+  Index *pIdx,         /* The index to be used for a inequality constraint */
+  int nEq,             /* Number of prior equality constraints on same index */
+  WhereTerm *pTerm     /* The vector inequality constraint */
+){
+  int nCmp = sqlite3ExprVectorSize(pTerm->pExpr->pLeft);
+  int i;
+
+  nCmp = MIN(nCmp, (pIdx->nColumn - nEq));
+  for(i=1; i<nCmp; i++){
+    /* Test if comparison i of pTerm is compatible with column (i+nEq)
+    ** of the index. If not, exit the loop.  */
+    char aff;                     /* Comparison affinity */
+    char idxaff = 0;              /* Indexed columns affinity */
+    CollSeq *pColl;               /* Comparison collation sequence */
+    Expr *pLhs, *pRhs;
+
+    assert( ExprUseXList(pTerm->pExpr->pLeft) );
+    pLhs = pTerm->pExpr->pLeft->x.pList->a[i].pExpr;
+    pRhs = pTerm->pExpr->pRight;
+    if( ExprUseXSelect(pRhs) ){
+      pRhs = pRhs->x.pSelect->pEList->a[i].pExpr;
+    }else{
+      pRhs = pRhs->x.pList->a[i].pExpr;
+    }
+
+    /* Check that the LHS of the comparison is a column reference to
+    ** the right column of the right source table. And that the sort
+    ** order of the index column is the same as the sort order of the
+    ** leftmost index column.  */
+    if( pLhs->op!=TK_COLUMN
+     || pLhs->iTable!=iCur
+     || pLhs->iColumn!=pIdx->aiColumn[i+nEq]
+     || pIdx->aSortOrder[i+nEq]!=pIdx->aSortOrder[nEq]
+    ){
+      break;
+    }
+
+    testcase( pLhs->iColumn==XN_ROWID );
+    aff = sqlite3CompareAffinity(pRhs, sqlite3ExprAffinity(pLhs));
+    idxaff = sqlite3TableColumnAffinity(pIdx->pTable, pLhs->iColumn);
+    if( aff!=idxaff ) break;
+
+    pColl = sqlite3BinaryCompareCollSeq(pParse, pLhs, pRhs);
+    if( pColl==0 ) break;
+    if( sqlite3StrICmp(pColl->zName, pIdx->azColl[i+nEq]) ) break;
+  }
+  return i;
+}
+
+/*
+** Adjust the cost C by the costMult factor T.  This only occurs if
+** compiled with -DSQLITE_ENABLE_COSTMULT
+*/
+#ifdef SQLITE_ENABLE_COSTMULT
+# define ApplyCostMultiplier(C,T)  C += T
+#else
+# define ApplyCostMultiplier(C,T)
+#endif
+
+/*
+** We have so far matched pBuilder->pNew->u.btree.nEq terms of the
+** index pIndex. Try to match one more.
+**
+** When this function is called, pBuilder->pNew->nOut contains the
+** number of rows expected to be visited by filtering using the nEq
+** terms only. If it is modified, this value is restored before this
+** function returns.
+**
+** If pProbe->idxType==SQLITE_IDXTYPE_IPK, that means pIndex is
+** a fake index used for the INTEGER PRIMARY KEY.
+*/
+static int whereLoopAddBtreeIndex(
+  WhereLoopBuilder *pBuilder,     /* The WhereLoop factory */
+  SrcItem *pSrc,                  /* FROM clause term being analyzed */
+  Index *pProbe,                  /* An index on pSrc */
+  LogEst nInMul                   /* log(Number of iterations due to IN) */
+){
+  WhereInfo *pWInfo = pBuilder->pWInfo;  /* WHERE analyze context */
+  Parse *pParse = pWInfo->pParse;        /* Parsing context */
+  sqlite3 *db = pParse->db;       /* Database connection malloc context */
+  WhereLoop *pNew;                /* Template WhereLoop under construction */
+  WhereTerm *pTerm;               /* A WhereTerm under consideration */
+  int opMask;                     /* Valid operators for constraints */
+  WhereScan scan;                 /* Iterator for WHERE terms */
+  Bitmask saved_prereq;           /* Original value of pNew->prereq */
+  u16 saved_nLTerm;               /* Original value of pNew->nLTerm */
+  u16 saved_nEq;                  /* Original value of pNew->u.btree.nEq */
+  u16 saved_nBtm;                 /* Original value of pNew->u.btree.nBtm */
+  u16 saved_nTop;                 /* Original value of pNew->u.btree.nTop */
+  u16 saved_nSkip;                /* Original value of pNew->nSkip */
+  u32 saved_wsFlags;              /* Original value of pNew->wsFlags */
+  LogEst saved_nOut;              /* Original value of pNew->nOut */
+  int rc = SQLITE_OK;             /* Return code */
+  LogEst rSize;                   /* Number of rows in the table */
+  LogEst rLogSize;                /* Logarithm of table size */
+  WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */
+
+  pNew = pBuilder->pNew;
+  assert( db->mallocFailed==0 || pParse->nErr>0 );
+  if( pParse->nErr ){
+    return pParse->rc;
+  }
+  WHERETRACE(0x800, ("BEGIN %s.addBtreeIdx(%s), nEq=%d, nSkip=%d, rRun=%d\n",
+                     pProbe->pTable->zName,pProbe->zName,
+                     pNew->u.btree.nEq, pNew->nSkip, pNew->rRun));
+
+  assert( (pNew->wsFlags & WHERE_VIRTUALTABLE)==0 );
+  assert( (pNew->wsFlags & WHERE_TOP_LIMIT)==0 );
+  if( pNew->wsFlags & WHERE_BTM_LIMIT ){
+    opMask = WO_LT|WO_LE;
+  }else{
+    assert( pNew->u.btree.nBtm==0 );
+    opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE|WO_ISNULL|WO_IS;
+  }
+  if( pProbe->bUnordered || pProbe->bLowQual ){
+    if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE);
+    if( pProbe->bLowQual && pSrc->fg.isIndexedBy==0 ){
+      opMask &= ~(WO_EQ|WO_IN|WO_IS);
+    }
+  }
+
+  assert( pNew->u.btree.nEq<pProbe->nColumn );
+  assert( pNew->u.btree.nEq<pProbe->nKeyCol
+       || pProbe->idxType!=SQLITE_IDXTYPE_PRIMARYKEY );
+
+  saved_nEq = pNew->u.btree.nEq;
+  saved_nBtm = pNew->u.btree.nBtm;
+  saved_nTop = pNew->u.btree.nTop;
+  saved_nSkip = pNew->nSkip;
+  saved_nLTerm = pNew->nLTerm;
+  saved_wsFlags = pNew->wsFlags;
+  saved_prereq = pNew->prereq;
+  saved_nOut = pNew->nOut;
+  pTerm = whereScanInit(&scan, pBuilder->pWC, pSrc->iCursor, saved_nEq,
+                        opMask, pProbe);
+  pNew->rSetup = 0;
+  rSize = pProbe->aiRowLogEst[0];
+  rLogSize = estLog(rSize);
+  for(; rc==SQLITE_OK && pTerm!=0; pTerm = whereScanNext(&scan)){
+    u16 eOp = pTerm->eOperator;   /* Shorthand for pTerm->eOperator */
+    LogEst rCostIdx;
+    LogEst nOutUnadjusted;        /* nOut before IN() and WHERE adjustments */
+    int nIn = 0;
+#ifdef SQLITE_ENABLE_STAT4
+    int nRecValid = pBuilder->nRecValid;
+#endif
+    if( (eOp==WO_ISNULL || (pTerm->wtFlags&TERM_VNULL)!=0)
+     && indexColumnNotNull(pProbe, saved_nEq)
+    ){
+      continue; /* ignore IS [NOT] NULL constraints on NOT NULL columns */
+    }
+    if( pTerm->prereqRight & pNew->maskSelf ) continue;
+
+    /* Do not allow the upper bound of a LIKE optimization range constraint
+    ** to mix with a lower range bound from some other source */
+    if( pTerm->wtFlags & TERM_LIKEOPT && pTerm->eOperator==WO_LT ) continue;
+
+    if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
+     && !constraintCompatibleWithOuterJoin(pTerm,pSrc)
+    ){
+      continue;
+    }
+    if( IsUniqueIndex(pProbe) && saved_nEq==pProbe->nKeyCol-1 ){
+      pBuilder->bldFlags1 |= SQLITE_BLDF1_UNIQUE;
+    }else{
+      pBuilder->bldFlags1 |= SQLITE_BLDF1_INDEXED;
+    }
+    pNew->wsFlags = saved_wsFlags;
+    pNew->u.btree.nEq = saved_nEq;
+    pNew->u.btree.nBtm = saved_nBtm;
+    pNew->u.btree.nTop = saved_nTop;
+    pNew->nLTerm = saved_nLTerm;
+    if( pNew->nLTerm>=pNew->nLSlot
+     && whereLoopResize(db, pNew, pNew->nLTerm+1)
+    ){
+       break; /* OOM while trying to enlarge the pNew->aLTerm array */
+    }
+    pNew->aLTerm[pNew->nLTerm++] = pTerm;
+    pNew->prereq = (saved_prereq | pTerm->prereqRight) & ~pNew->maskSelf;
+
+    assert( nInMul==0
+        || (pNew->wsFlags & WHERE_COLUMN_NULL)!=0
+        || (pNew->wsFlags & WHERE_COLUMN_IN)!=0
+        || (pNew->wsFlags & WHERE_SKIPSCAN)!=0
+    );
+
+    if( eOp & WO_IN ){
+      Expr *pExpr = pTerm->pExpr;
+      if( ExprUseXSelect(pExpr) ){
+        /* "x IN (SELECT ...)":  TUNING: the SELECT returns 25 rows */
+        int i;
+        nIn = 46;  assert( 46==sqlite3LogEst(25) );
+
+        /* The expression may actually be of the form (x, y) IN (SELECT...).
+        ** In this case there is a separate term for each of (x) and (y).
+        ** However, the nIn multiplier should only be applied once, not once
+        ** for each such term. The following loop checks that pTerm is the
+        ** first such term in use, and sets nIn back to 0 if it is not. */
+        for(i=0; i<pNew->nLTerm-1; i++){
+          if( pNew->aLTerm[i] && pNew->aLTerm[i]->pExpr==pExpr ) nIn = 0;
+        }
+      }else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
+        /* "x IN (value, value, ...)" */
+        nIn = sqlite3LogEst(pExpr->x.pList->nExpr);
+      }
+      if( pProbe->hasStat1 && rLogSize>=10 ){
+        LogEst M, logK, x;
+        /* Let:
+        **   N = the total number of rows in the table
+        **   K = the number of entries on the RHS of the IN operator
+        **   M = the number of rows in the table that match terms to the
+        **       to the left in the same index.  If the IN operator is on
+        **       the left-most index column, M==N.
+        **
+        ** Given the definitions above, it is better to omit the IN operator
+        ** from the index lookup and instead do a scan of the M elements,
+        ** testing each scanned row against the IN operator separately, if:
+        **
+        **        M*log(K) < K*log(N)
+        **
+        ** Our estimates for M, K, and N might be inaccurate, so we build in
+        ** a safety margin of 2 (LogEst: 10) that favors using the IN operator
+        ** with the index, as using an index has better worst-case behavior.
+        ** If we do not have real sqlite_stat1 data, always prefer to use
+        ** the index.  Do not bother with this optimization on very small
+        ** tables (less than 2 rows) as it is pointless in that case.
+        */
+        M = pProbe->aiRowLogEst[saved_nEq];
+        logK = estLog(nIn);
+        /* TUNING      v-----  10 to bias toward indexed IN */
+        x = M + logK + 10 - (nIn + rLogSize);
+        if( x>=0 ){
+          WHERETRACE(0x40,
+            ("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d) "
+             "prefers indexed lookup\n",
+             saved_nEq, M, logK, nIn, rLogSize, x));
+        }else if( nInMul<2 && OptimizationEnabled(db, SQLITE_SeekScan) ){
+          WHERETRACE(0x40,
+            ("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d"
+             " nInMul=%d) prefers skip-scan\n",
+             saved_nEq, M, logK, nIn, rLogSize, x, nInMul));
+          pNew->wsFlags |= WHERE_IN_SEEKSCAN;
+        }else{
+          WHERETRACE(0x40,
+            ("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d"
+             " nInMul=%d) prefers normal scan\n",
+             saved_nEq, M, logK, nIn, rLogSize, x, nInMul));
+          continue;
+        }
+      }
+      pNew->wsFlags |= WHERE_COLUMN_IN;
+    }else if( eOp & (WO_EQ|WO_IS) ){
+      int iCol = pProbe->aiColumn[saved_nEq];
+      pNew->wsFlags |= WHERE_COLUMN_EQ;
+      assert( saved_nEq==pNew->u.btree.nEq );
+      if( iCol==XN_ROWID
+       || (iCol>=0 && nInMul==0 && saved_nEq==pProbe->nKeyCol-1)
+      ){
+        if( iCol==XN_ROWID || pProbe->uniqNotNull
+         || (pProbe->nKeyCol==1 && pProbe->onError && (eOp & WO_EQ))
+        ){
+          pNew->wsFlags |= WHERE_ONEROW;
+        }else{
+          pNew->wsFlags |= WHERE_UNQ_WANTED;
+        }
+      }
+      if( scan.iEquiv>1 ) pNew->wsFlags |= WHERE_TRANSCONS;
+    }else if( eOp & WO_ISNULL ){
+      pNew->wsFlags |= WHERE_COLUMN_NULL;
+    }else{
+      int nVecLen = whereRangeVectorLen(
+          pParse, pSrc->iCursor, pProbe, saved_nEq, pTerm
+      );
+      if( eOp & (WO_GT|WO_GE) ){
+        testcase( eOp & WO_GT );
+        testcase( eOp & WO_GE );
+        pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_BTM_LIMIT;
+        pNew->u.btree.nBtm = nVecLen;
+        pBtm = pTerm;
+        pTop = 0;
+        if( pTerm->wtFlags & TERM_LIKEOPT ){
+          /* Range constraints that come from the LIKE optimization are
+          ** always used in pairs. */
+          pTop = &pTerm[1];
+          assert( (pTop-(pTerm->pWC->a))<pTerm->pWC->nTerm );
+          assert( pTop->wtFlags & TERM_LIKEOPT );
+          assert( pTop->eOperator==WO_LT );
+          if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */
+          pNew->aLTerm[pNew->nLTerm++] = pTop;
+          pNew->wsFlags |= WHERE_TOP_LIMIT;
+          pNew->u.btree.nTop = 1;
+        }
+      }else{
+        assert( eOp & (WO_LT|WO_LE) );
+        testcase( eOp & WO_LT );
+        testcase( eOp & WO_LE );
+        pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_TOP_LIMIT;
+        pNew->u.btree.nTop = nVecLen;
+        pTop = pTerm;
+        pBtm = (pNew->wsFlags & WHERE_BTM_LIMIT)!=0 ?
+                       pNew->aLTerm[pNew->nLTerm-2] : 0;
+      }
+    }
+
+    /* At this point pNew->nOut is set to the number of rows expected to
+    ** be visited by the index scan before considering term pTerm, or the
+    ** values of nIn and nInMul. In other words, assuming that all
+    ** "x IN(...)" terms are replaced with "x = ?". This block updates
+    ** the value of pNew->nOut to account for pTerm (but not nIn/nInMul).  */
+    assert( pNew->nOut==saved_nOut );
+    if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
+      /* Adjust nOut using stat4 data. Or, if there is no stat4
+      ** data, using some other estimate.  */
+      whereRangeScanEst(pParse, pBuilder, pBtm, pTop, pNew);
+    }else{
+      int nEq = ++pNew->u.btree.nEq;
+      assert( eOp & (WO_ISNULL|WO_EQ|WO_IN|WO_IS) );
+
+      assert( pNew->nOut==saved_nOut );
+      if( pTerm->truthProb<=0 && pProbe->aiColumn[saved_nEq]>=0 ){
+        assert( (eOp & WO_IN) || nIn==0 );
+        testcase( eOp & WO_IN );
+        pNew->nOut += pTerm->truthProb;
+        pNew->nOut -= nIn;
+      }else{
+#ifdef SQLITE_ENABLE_STAT4
+        tRowcnt nOut = 0;
+        if( nInMul==0
+         && pProbe->nSample
+         && ALWAYS(pNew->u.btree.nEq<=pProbe->nSampleCol)
+         && ((eOp & WO_IN)==0 || ExprUseXList(pTerm->pExpr))
+         && OptimizationEnabled(db, SQLITE_Stat4)
+        ){
+          Expr *pExpr = pTerm->pExpr;
+          if( (eOp & (WO_EQ|WO_ISNULL|WO_IS))!=0 ){
+            testcase( eOp & WO_EQ );
+            testcase( eOp & WO_IS );
+            testcase( eOp & WO_ISNULL );
+            rc = whereEqualScanEst(pParse, pBuilder, pExpr->pRight, &nOut);
+          }else{
+            rc = whereInScanEst(pParse, pBuilder, pExpr->x.pList, &nOut);
+          }
+          if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+          if( rc!=SQLITE_OK ) break;          /* Jump out of the pTerm loop */
+          if( nOut ){
+            pNew->nOut = sqlite3LogEst(nOut);
+            if( nEq==1
+             /* TUNING: Mark terms as "low selectivity" if they seem likely
+             ** to be true for half or more of the rows in the table.
+             ** See tag-202002240-1 */
+             && pNew->nOut+10 > pProbe->aiRowLogEst[0]
+            ){
+#if WHERETRACE_ENABLED /* 0x01 */
+              if( sqlite3WhereTrace & 0x20 ){
+                sqlite3DebugPrintf(
+                   "STAT4 determines term has low selectivity:\n");
+                sqlite3WhereTermPrint(pTerm, 999);
+              }
+#endif
+              pTerm->wtFlags |= TERM_HIGHTRUTH;
+              if( pTerm->wtFlags & TERM_HEURTRUTH ){
+                /* If the term has previously been used with an assumption of
+                ** higher selectivity, then set the flag to rerun the
+                ** loop computations. */
+                pBuilder->bldFlags2 |= SQLITE_BLDF2_2NDPASS;
+              }
+            }
+            if( pNew->nOut>saved_nOut ) pNew->nOut = saved_nOut;
+            pNew->nOut -= nIn;
+          }
+        }
+        if( nOut==0 )
+#endif
+        {
+          pNew->nOut += (pProbe->aiRowLogEst[nEq] - pProbe->aiRowLogEst[nEq-1]);
+          if( eOp & WO_ISNULL ){
+            /* TUNING: If there is no likelihood() value, assume that a
+            ** "col IS NULL" expression matches twice as many rows
+            ** as (col=?). */
+            pNew->nOut += 10;
+          }
+        }
+      }
+    }
+
+    /* Set rCostIdx to the estimated cost of visiting selected rows in the
+    ** index.  The estimate is the sum of two values:
+    **   1.  The cost of doing one search-by-key to find the first matching
+    **       entry
+    **   2.  Stepping forward in the index pNew->nOut times to find all
+    **       additional matching entries.
+    */
+    assert( pSrc->pSTab->szTabRow>0 );
+    if( pProbe->idxType==SQLITE_IDXTYPE_IPK ){
+      /* The pProbe->szIdxRow is low for an IPK table since the interior
+      ** pages are small.  Thus szIdxRow gives a good estimate of seek cost.
+      ** But the leaf pages are full-size, so pProbe->szIdxRow would badly
+      ** under-estimate the scanning cost. */
+      rCostIdx = pNew->nOut + 16;
+    }else{
+      rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pSTab->szTabRow;
+    }
+    rCostIdx = sqlite3LogEstAdd(rLogSize, rCostIdx);
+
+    /* Estimate the cost of running the loop.  If all data is coming
+    ** from the index, then this is just the cost of doing the index
+    ** lookup and scan.  But if some data is coming out of the main table,
+    ** we also have to add in the cost of doing pNew->nOut searches to
+    ** locate the row in the main table that corresponds to the index entry.
+    */
+    pNew->rRun = rCostIdx;
+    if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK|WHERE_EXPRIDX))==0 ){
+      pNew->rRun = sqlite3LogEstAdd(pNew->rRun, pNew->nOut + 16);
+    }
+    ApplyCostMultiplier(pNew->rRun, pProbe->pTable->costMult);
+
+    nOutUnadjusted = pNew->nOut;
+    pNew->rRun += nInMul + nIn;
+    pNew->nOut += nInMul + nIn;
+    whereLoopOutputAdjust(pBuilder->pWC, pNew, rSize);
+    rc = whereLoopInsert(pBuilder, pNew);
+
+    if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
+      pNew->nOut = saved_nOut;
+    }else{
+      pNew->nOut = nOutUnadjusted;
+    }
+
+    if( (pNew->wsFlags & WHERE_TOP_LIMIT)==0
+     && pNew->u.btree.nEq<pProbe->nColumn
+     && (pNew->u.btree.nEq<pProbe->nKeyCol ||
+          (pProbe->idxType!=SQLITE_IDXTYPE_PRIMARYKEY && !pProbe->bIdxRowid))
+    ){
+      if( pNew->u.btree.nEq>3 ){
+        sqlite3ProgressCheck(pParse);
+      }
+      whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nInMul+nIn);
+    }
+    pNew->nOut = saved_nOut;
+#ifdef SQLITE_ENABLE_STAT4
+    pBuilder->nRecValid = nRecValid;
+#endif
+  }
+  pNew->prereq = saved_prereq;
+  pNew->u.btree.nEq = saved_nEq;
+  pNew->u.btree.nBtm = saved_nBtm;
+  pNew->u.btree.nTop = saved_nTop;
+  pNew->nSkip = saved_nSkip;
+  pNew->wsFlags = saved_wsFlags;
+  pNew->nOut = saved_nOut;
+  pNew->nLTerm = saved_nLTerm;
+
+  /* Consider using a skip-scan if there are no WHERE clause constraints
+  ** available for the left-most terms of the index, and if the average
+  ** number of repeats in the left-most terms is at least 18.
+  **
+  ** The magic number 18 is selected on the basis that scanning 17 rows
+  ** is almost always quicker than an index seek (even though if the index
+  ** contains fewer than 2^17 rows we assume otherwise in other parts of
+  ** the code). And, even if it is not, it should not be too much slower.
+  ** On the other hand, the extra seeks could end up being significantly
+  ** more expensive.  */
+  assert( 42==sqlite3LogEst(18) );
+  if( saved_nEq==saved_nSkip
+   && saved_nEq+1<pProbe->nKeyCol
+   && saved_nEq==pNew->nLTerm
+   && pProbe->noSkipScan==0
+   && pProbe->hasStat1!=0
+   && OptimizationEnabled(db, SQLITE_SkipScan)
+   && pProbe->aiRowLogEst[saved_nEq+1]>=42  /* TUNING: Minimum for skip-scan */
+   && (rc = whereLoopResize(db, pNew, pNew->nLTerm+1))==SQLITE_OK
+  ){
+    LogEst nIter;
+    pNew->u.btree.nEq++;
+    pNew->nSkip++;
+    pNew->aLTerm[pNew->nLTerm++] = 0;
+    pNew->wsFlags |= WHERE_SKIPSCAN;
+    nIter = pProbe->aiRowLogEst[saved_nEq] - pProbe->aiRowLogEst[saved_nEq+1];
+    pNew->nOut -= nIter;
+    /* TUNING:  Because uncertainties in the estimates for skip-scan queries,
+    ** add a 1.375 fudge factor to make skip-scan slightly less likely. */
+    nIter += 5;
+    whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nIter + nInMul);
+    pNew->nOut = saved_nOut;
+    pNew->u.btree.nEq = saved_nEq;
+    pNew->nSkip = saved_nSkip;
+    pNew->wsFlags = saved_wsFlags;
+  }
+
+  WHERETRACE(0x800, ("END %s.addBtreeIdx(%s), nEq=%d, rc=%d\n",
+                      pProbe->pTable->zName, pProbe->zName, saved_nEq, rc));
+  return rc;
+}
+
+/*
+** Return True if it is possible that pIndex might be useful in
+** implementing the ORDER BY clause in pBuilder.
+**
+** Return False if pBuilder does not contain an ORDER BY clause or
+** if there is no way for pIndex to be useful in implementing that
+** ORDER BY clause.
+*/
+static int indexMightHelpWithOrderBy(
+  WhereLoopBuilder *pBuilder,
+  Index *pIndex,
+  int iCursor
+){
+  ExprList *pOB;
+  ExprList *aColExpr;
+  int ii, jj;
+
+  if( pIndex->bUnordered ) return 0;
+  if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
+  for(ii=0; ii<pOB->nExpr; ii++){
+    Expr *pExpr = sqlite3ExprSkipCollateAndLikely(pOB->a[ii].pExpr);
+    if( NEVER(pExpr==0) ) continue;
+    if( (pExpr->op==TK_COLUMN || pExpr->op==TK_AGG_COLUMN)
+     && pExpr->iTable==iCursor
+    ){
+      if( pExpr->iColumn<0 ) return 1;
+      for(jj=0; jj<pIndex->nKeyCol; jj++){
+        if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
+      }
+    }else if( (aColExpr = pIndex->aColExpr)!=0 ){
+      for(jj=0; jj<pIndex->nKeyCol; jj++){
+        if( pIndex->aiColumn[jj]!=XN_EXPR ) continue;
+        if( sqlite3ExprCompareSkip(pExpr,aColExpr->a[jj].pExpr,iCursor)==0 ){
+          return 1;
+        }
+      }
+    }
+  }
+  return 0;
+}
+
+/* Check to see if a partial index with pPartIndexWhere can be used
+** in the current query.  Return true if it can be and false if not.
+*/
+static int whereUsablePartialIndex(
+  int iTab,             /* The table for which we want an index */
+  u8 jointype,          /* The JT_* flags on the join */
+  WhereClause *pWC,     /* The WHERE clause of the query */
+  Expr *pWhere          /* The WHERE clause from the partial index */
+){
+  int i;
+  WhereTerm *pTerm;
+  Parse *pParse;
+
+  if( jointype & JT_LTORJ ) return 0;
+  pParse = pWC->pWInfo->pParse;
+  while( pWhere->op==TK_AND ){
+    if( !whereUsablePartialIndex(iTab,jointype,pWC,pWhere->pLeft) ) return 0;
+    pWhere = pWhere->pRight;
+  }
+  for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+    Expr *pExpr;
+    pExpr = pTerm->pExpr;
+    if( (!ExprHasProperty(pExpr, EP_OuterON) || pExpr->w.iJoin==iTab)
+     && ((jointype & JT_OUTER)==0 || ExprHasProperty(pExpr, EP_OuterON))
+     && sqlite3ExprImpliesExpr(pParse, pExpr, pWhere, iTab)
+     && (pTerm->wtFlags & TERM_VNULL)==0
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** pIdx is an index containing expressions.  Check it see if any of the
+** expressions in the index match the pExpr expression.
+*/
+static int exprIsCoveredByIndex(
+  const Expr *pExpr,
+  const Index *pIdx,
+  int iTabCur
+){
+  int i;
+  for(i=0; i<pIdx->nColumn; i++){
+    if( pIdx->aiColumn[i]==XN_EXPR
+     && sqlite3ExprCompare(0, pExpr, pIdx->aColExpr->a[i].pExpr, iTabCur)==0
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Structure passed to the whereIsCoveringIndex Walker callback.
+*/
+typedef struct CoveringIndexCheck CoveringIndexCheck;
+struct CoveringIndexCheck {
+  Index *pIdx;       /* The index */
+  int iTabCur;       /* Cursor number for the corresponding table */
+  u8 bExpr;          /* Uses an indexed expression */
+  u8 bUnidx;         /* Uses an unindexed column not within an indexed expr */
+};
+
+/*
+** Information passed in is pWalk->u.pCovIdxCk.  Call it pCk.
+**
+** If the Expr node references the table with cursor pCk->iTabCur, then
+** make sure that column is covered by the index pCk->pIdx.  We know that
+** all columns less than 63 (really BMS-1) are covered, so we don't need
+** to check them.  But we do need to check any column at 63 or greater.
+**
+** If the index does not cover the column, then set pWalk->eCode to
+** non-zero and return WRC_Abort to stop the search.
+**
+** If this node does not disprove that the index can be a covering index,
+** then just return WRC_Continue, to continue the search.
+**
+** If pCk->pIdx contains indexed expressions and one of those expressions
+** matches pExpr, then prune the search.
+*/
+static int whereIsCoveringIndexWalkCallback(Walker *pWalk, Expr *pExpr){
+  int i;                    /* Loop counter */
+  const Index *pIdx;        /* The index of interest */
+  const i16 *aiColumn;      /* Columns contained in the index */
+  u16 nColumn;              /* Number of columns in the index */
+  CoveringIndexCheck *pCk;  /* Info about this search */
+
+  pCk = pWalk->u.pCovIdxCk;
+  pIdx = pCk->pIdx;
+  if( (pExpr->op==TK_COLUMN || pExpr->op==TK_AGG_COLUMN) ){
+    /* if( pExpr->iColumn<(BMS-1) && pIdx->bHasExpr==0 ) return WRC_Continue;*/
+    if( pExpr->iTable!=pCk->iTabCur ) return WRC_Continue;
+    pIdx = pWalk->u.pCovIdxCk->pIdx;
+    aiColumn = pIdx->aiColumn;
+    nColumn = pIdx->nColumn;
+    for(i=0; i<nColumn; i++){
+      if( aiColumn[i]==pExpr->iColumn ) return WRC_Continue;
+    }
+    pCk->bUnidx = 1;
+    return WRC_Abort;
+  }else if( pIdx->bHasExpr
+         && exprIsCoveredByIndex(pExpr, pIdx, pWalk->u.pCovIdxCk->iTabCur) ){
+    pCk->bExpr = 1;
+    return WRC_Prune;
+  }
+  return WRC_Continue;
+}
+
+
+/*
+** pIdx is an index that covers all of the low-number columns used by
+** pWInfo->pSelect (columns from 0 through 62) or an index that has
+** expressions terms.  Hence, we cannot determine whether or not it is
+** a covering index by using the colUsed bitmasks.  We have to do a search
+** to see if the index is covering.  This routine does that search.
+**
+** The return value is one of these:
+**
+**      0                The index is definitely not a covering index
+**
+**      WHERE_IDX_ONLY   The index is definitely a covering index
+**
+**      WHERE_EXPRIDX    The index is likely a covering index, but it is
+**                       difficult to determine precisely because of the
+**                       expressions that are indexed.  Score it as a
+**                       covering index, but still keep the main table open
+**                       just in case we need it.
+**
+** This routine is an optimization.  It is always safe to return zero.
+** But returning one of the other two values when zero should have been
+** returned can lead to incorrect bytecode and assertion faults.
+*/
+static SQLITE_NOINLINE u32 whereIsCoveringIndex(
+  WhereInfo *pWInfo,     /* The WHERE clause context */
+  Index *pIdx,           /* Index that is being tested */
+  int iTabCur            /* Cursor for the table being indexed */
+){
+  int i, rc;
+  struct CoveringIndexCheck ck;
+  Walker w;
+  if( pWInfo->pSelect==0 ){
+    /* We don't have access to the full query, so we cannot check to see
+    ** if pIdx is covering.  Assume it is not. */
+    return 0;
+  }
+  if( pIdx->bHasExpr==0 ){
+    for(i=0; i<pIdx->nColumn; i++){
+      if( pIdx->aiColumn[i]>=BMS-1 ) break;
+    }
+    if( i>=pIdx->nColumn ){
+      /* pIdx does not index any columns greater than 62, but we know from
+      ** colMask that columns greater than 62 are used, so this is not a
+      ** covering index */
+      return 0;
+    }
+  }
+  ck.pIdx = pIdx;
+  ck.iTabCur = iTabCur;
+  ck.bExpr = 0;
+  ck.bUnidx = 0;
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = whereIsCoveringIndexWalkCallback;
+  w.xSelectCallback = sqlite3SelectWalkNoop;
+  w.u.pCovIdxCk = &ck;
+  sqlite3WalkSelect(&w, pWInfo->pSelect);
+  if( ck.bUnidx ){
+    rc = 0;
+  }else if( ck.bExpr ){
+    rc = WHERE_EXPRIDX;
+  }else{
+    rc = WHERE_IDX_ONLY;
+  }
+  return rc;
+}
+
+/*
+** This is an sqlite3ParserAddCleanup() callback that is invoked to
+** free the Parse->pIdxEpr list when the Parse object is destroyed.
+*/
+static void whereIndexedExprCleanup(sqlite3 *db, void *pObject){
+  IndexedExpr **pp = (IndexedExpr**)pObject;
+  while( *pp!=0 ){
+    IndexedExpr *p = *pp;
+    *pp = p->pIENext;
+    sqlite3ExprDelete(db, p->pExpr);
+    sqlite3DbFreeNN(db, p);
+  }
+}
+
+/*
+** This function is called for a partial index - one with a WHERE clause - in
+** two scenarios. In both cases, it determines whether or not the WHERE
+** clause on the index implies that a column of the table may be safely
+** replaced by a constant expression. For example, in the following
+** SELECT:
+**
+**   CREATE INDEX i1 ON t1(b, c) WHERE a=<expr>;
+**   SELECT a, b, c FROM t1 WHERE a=<expr> AND b=?;
+**
+** The "a" in the select-list may be replaced by <expr>, iff:
+**
+**    (a) <expr> is a constant expression, and
+**    (b) The (a=<expr>) comparison uses the BINARY collation sequence, and
+**    (c) Column "a" has an affinity other than NONE or BLOB.
+**
+** If argument pItem is NULL, then pMask must not be NULL. In this case this
+** function is being called as part of determining whether or not pIdx
+** is a covering index. This function clears any bits in (*pMask)
+** corresponding to columns that may be replaced by constants as described
+** above.
+**
+** Otherwise, if pItem is not NULL, then this function is being called
+** as part of coding a loop that uses index pIdx. In this case, add entries
+** to the Parse.pIdxPartExpr list for each column that can be replaced
+** by a constant.
+*/
+static void wherePartIdxExpr(
+  Parse *pParse,                  /* Parse context */
+  Index *pIdx,                    /* Partial index being processed */
+  Expr *pPart,                    /* WHERE clause being processed */
+  Bitmask *pMask,                 /* Mask to clear bits in */
+  int iIdxCur,                    /* Cursor number for index */
+  SrcItem *pItem                  /* The FROM clause entry for the table */
+){
+  assert( pItem==0 || (pItem->fg.jointype & JT_RIGHT)==0 );
+  assert( (pItem==0 || pMask==0) && (pMask!=0 || pItem!=0) );
+
+  if( pPart->op==TK_AND ){
+    wherePartIdxExpr(pParse, pIdx, pPart->pRight, pMask, iIdxCur, pItem);
+    pPart = pPart->pLeft;
+  }
+
+  if( (pPart->op==TK_EQ || pPart->op==TK_IS) ){
+    Expr *pLeft = pPart->pLeft;
+    Expr *pRight = pPart->pRight;
+    u8 aff;
+
+    if( pLeft->op!=TK_COLUMN ) return;
+    if( !sqlite3ExprIsConstant(0, pRight) ) return;
+    if( !sqlite3IsBinary(sqlite3ExprCompareCollSeq(pParse, pPart)) ) return;
+    if( pLeft->iColumn<0 ) return;
+    aff = pIdx->pTable->aCol[pLeft->iColumn].affinity;
+    if( aff>=SQLITE_AFF_TEXT ){
+      if( pItem ){
+        sqlite3 *db = pParse->db;
+        IndexedExpr *p = (IndexedExpr*)sqlite3DbMallocRaw(db, sizeof(*p));
+        if( p ){
+          int bNullRow = (pItem->fg.jointype&(JT_LEFT|JT_LTORJ))!=0;
+          p->pExpr = sqlite3ExprDup(db, pRight, 0);
+          p->iDataCur = pItem->iCursor;
+          p->iIdxCur = iIdxCur;
+          p->iIdxCol = pLeft->iColumn;
+          p->bMaybeNullRow = bNullRow;
+          p->pIENext = pParse->pIdxPartExpr;
+          p->aff = aff;
+          pParse->pIdxPartExpr = p;
+          if( p->pIENext==0 ){
+            void *pArg = (void*)&pParse->pIdxPartExpr;
+            sqlite3ParserAddCleanup(pParse, whereIndexedExprCleanup, pArg);
+          }
+        }
+      }else if( pLeft->iColumn<(BMS-1) ){
+        *pMask &= ~((Bitmask)1 << pLeft->iColumn);
+      }
+    }
+  }
+}
+
+
+/*
+** Add all WhereLoop objects for a single table of the join where the table
+** is identified by pBuilder->pNew->iTab.  That table is guaranteed to be
+** a b-tree table, not a virtual table.
+**
+** The costs (WhereLoop.rRun) of the b-tree loops added by this function
+** are calculated as follows:
+**
+** For a full scan, assuming the table (or index) contains nRow rows:
+**
+**     cost = nRow * 3.0                    // full-table scan
+**     cost = nRow * K                      // scan of covering index
+**     cost = nRow * (K+3.0)                // scan of non-covering index
+**
+** where K is a value between 1.1 and 3.0 set based on the relative
+** estimated average size of the index and table records.
+**
+** For an index scan, where nVisit is the number of index rows visited
+** by the scan, and nSeek is the number of seek operations required on
+** the index b-tree:
+**
+**     cost = nSeek * (log(nRow) + K * nVisit)          // covering index
+**     cost = nSeek * (log(nRow) + (K+3.0) * nVisit)    // non-covering index
+**
+** Normally, nSeek is 1. nSeek values greater than 1 come about if the
+** WHERE clause includes "x IN (....)" terms used in place of "x=?". Or when
+** implicit "x IN (SELECT x FROM tbl)" terms are added for skip-scans.
+**
+** The estimated values (nRow, nVisit, nSeek) often contain a large amount
+** of uncertainty.  For this reason, scoring is designed to pick plans that
+** "do the least harm" if the estimates are inaccurate.  For example, a
+** log(nRow) factor is omitted from a non-covering index scan in order to
+** bias the scoring in favor of using an index, since the worst-case
+** performance of using an index is far better than the worst-case performance
+** of a full table scan.
+*/
+static int whereLoopAddBtree(
+  WhereLoopBuilder *pBuilder, /* WHERE clause information */
+  Bitmask mPrereq             /* Extra prerequisites for using this table */
+){
+  WhereInfo *pWInfo;          /* WHERE analysis context */
+  Index *pProbe;              /* An index we are evaluating */
+  Index sPk;                  /* A fake index object for the primary key */
+  LogEst aiRowEstPk[2];       /* The aiRowLogEst[] value for the sPk index */
+  i16 aiColumnPk = -1;        /* The aColumn[] value for the sPk index */
+  SrcList *pTabList;          /* The FROM clause */
+  SrcItem *pSrc;              /* The FROM clause btree term to add */
+  WhereLoop *pNew;            /* Template WhereLoop object */
+  int rc = SQLITE_OK;         /* Return code */
+  int iSortIdx = 1;           /* Index number */
+  int b;                      /* A boolean value */
+  LogEst rSize;               /* number of rows in the table */
+  WhereClause *pWC;           /* The parsed WHERE clause */
+  Table *pTab;                /* Table being queried */
+
+  pNew = pBuilder->pNew;
+  pWInfo = pBuilder->pWInfo;
+  pTabList = pWInfo->pTabList;
+  pSrc = pTabList->a + pNew->iTab;
+  pTab = pSrc->pSTab;
+  pWC = pBuilder->pWC;
+  assert( !IsVirtual(pSrc->pSTab) );
+
+  if( pSrc->fg.isIndexedBy ){
+    assert( pSrc->fg.isCte==0 );
+    /* An INDEXED BY clause specifies a particular index to use */
+    pProbe = pSrc->u2.pIBIndex;
+  }else if( !HasRowid(pTab) ){
+    pProbe = pTab->pIndex;
+  }else{
+    /* There is no INDEXED BY clause.  Create a fake Index object in local
+    ** variable sPk to represent the rowid primary key index.  Make this
+    ** fake index the first in a chain of Index objects with all of the real
+    ** indices to follow */
+    Index *pFirst;                  /* First of real indices on the table */
+    memset(&sPk, 0, sizeof(Index));
+    sPk.nKeyCol = 1;
+    sPk.nColumn = 1;
+    sPk.aiColumn = &aiColumnPk;
+    sPk.aiRowLogEst = aiRowEstPk;
+    sPk.onError = OE_Replace;
+    sPk.pTable = pTab;
+    sPk.szIdxRow = 3;  /* TUNING: Interior rows of IPK table are very small */
+    sPk.idxType = SQLITE_IDXTYPE_IPK;
+    aiRowEstPk[0] = pTab->nRowLogEst;
+    aiRowEstPk[1] = 0;
+    pFirst = pSrc->pSTab->pIndex;
+    if( pSrc->fg.notIndexed==0 ){
+      /* The real indices of the table are only considered if the
+      ** NOT INDEXED qualifier is omitted from the FROM clause */
+      sPk.pNext = pFirst;
+    }
+    pProbe = &sPk;
+  }
+  rSize = pTab->nRowLogEst;
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+  /* Automatic indexes */
+  if( !pBuilder->pOrSet      /* Not part of an OR optimization */
+   && (pWInfo->wctrlFlags & (WHERE_RIGHT_JOIN|WHERE_OR_SUBCLAUSE))==0
+   && (pWInfo->pParse->db->flags & SQLITE_AutoIndex)!=0
+   && !pSrc->fg.isIndexedBy  /* Has no INDEXED BY clause */
+   && !pSrc->fg.notIndexed   /* Has no NOT INDEXED clause */
+   && !pSrc->fg.isCorrelated /* Not a correlated subquery */
+   && !pSrc->fg.isRecursive  /* Not a recursive common table expression. */
+   && (pSrc->fg.jointype & JT_RIGHT)==0 /* Not the right tab of a RIGHT JOIN */
+  ){
+    /* Generate auto-index WhereLoops */
+    LogEst rLogSize;         /* Logarithm of the number of rows in the table */
+    WhereTerm *pTerm;
+    WhereTerm *pWCEnd = pWC->a + pWC->nTerm;
+    rLogSize = estLog(rSize);
+    for(pTerm=pWC->a; rc==SQLITE_OK && pTerm<pWCEnd; pTerm++){
+      if( pTerm->prereqRight & pNew->maskSelf ) continue;
+      if( termCanDriveIndex(pTerm, pSrc, 0) ){
+        pNew->u.btree.nEq = 1;
+        pNew->nSkip = 0;
+        pNew->u.btree.pIndex = 0;
+        pNew->nLTerm = 1;
+        pNew->aLTerm[0] = pTerm;
+        /* TUNING: One-time cost for computing the automatic index is
+        ** estimated to be X*N*log2(N) where N is the number of rows in
+        ** the table being indexed and where X is 7 (LogEst=28) for normal
+        ** tables or 0.5 (LogEst=-10) for views and subqueries.  The value
+        ** of X is smaller for views and subqueries so that the query planner
+        ** will be more aggressive about generating automatic indexes for
+        ** those objects, since there is no opportunity to add schema
+        ** indexes on subqueries and views. */
+        pNew->rSetup = rLogSize + rSize;
+        if( !IsView(pTab) && (pTab->tabFlags & TF_Ephemeral)==0 ){
+          pNew->rSetup += 28;
+        }else{
+          pNew->rSetup -= 25;  /* Greatly reduced setup cost for auto indexes
+                               ** on ephemeral materializations of views */
+        }
+        ApplyCostMultiplier(pNew->rSetup, pTab->costMult);
+        if( pNew->rSetup<0 ) pNew->rSetup = 0;
+        /* TUNING: Each index lookup yields 20 rows in the table.  This
+        ** is more than the usual guess of 10 rows, since we have no way
+        ** of knowing how selective the index will ultimately be.  It would
+        ** not be unreasonable to make this value much larger. */
+        pNew->nOut = 43;  assert( 43==sqlite3LogEst(20) );
+        pNew->rRun = sqlite3LogEstAdd(rLogSize,pNew->nOut);
+        pNew->wsFlags = WHERE_AUTO_INDEX;
+        pNew->prereq = mPrereq | pTerm->prereqRight;
+        rc = whereLoopInsert(pBuilder, pNew);
+      }
+    }
+  }
+#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
+
+  /* Loop over all indices. If there was an INDEXED BY clause, then only
+  ** consider index pProbe.  */
+  for(; rc==SQLITE_OK && pProbe;
+      pProbe=(pSrc->fg.isIndexedBy ? 0 : pProbe->pNext), iSortIdx++
+  ){
+    if( pProbe->pPartIdxWhere!=0
+     && !whereUsablePartialIndex(pSrc->iCursor, pSrc->fg.jointype, pWC,
+                                 pProbe->pPartIdxWhere)
+    ){
+      testcase( pNew->iTab!=pSrc->iCursor );  /* See ticket [98d973b8f5] */
+      continue;  /* Partial index inappropriate for this query */
+    }
+    if( pProbe->bNoQuery ) continue;
+    rSize = pProbe->aiRowLogEst[0];
+    pNew->u.btree.nEq = 0;
+    pNew->u.btree.nBtm = 0;
+    pNew->u.btree.nTop = 0;
+    pNew->nSkip = 0;
+    pNew->nLTerm = 0;
+    pNew->iSortIdx = 0;
+    pNew->rSetup = 0;
+    pNew->prereq = mPrereq;
+    pNew->nOut = rSize;
+    pNew->u.btree.pIndex = pProbe;
+    pNew->u.btree.pOrderBy = 0;
+    b = indexMightHelpWithOrderBy(pBuilder, pProbe, pSrc->iCursor);
+
+    /* The ONEPASS_DESIRED flags never occurs together with ORDER BY */
+    assert( (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || b==0 );
+    if( pProbe->idxType==SQLITE_IDXTYPE_IPK ){
+      /* Integer primary key index */
+      pNew->wsFlags = WHERE_IPK;
+
+      /* Full table scan */
+      pNew->iSortIdx = b ? iSortIdx : 0;
+      /* TUNING: Cost of full table scan is 3.0*N.  The 3.0 factor is an
+      ** extra cost designed to discourage the use of full table scans,
+      ** since index lookups have better worst-case performance if our
+      ** stat guesses are wrong.  Reduce the 3.0 penalty slightly
+      ** (to 2.75) if we have valid STAT4 information for the table.
+      ** At 2.75, a full table scan is preferred over using an index on
+      ** a column with just two distinct values where each value has about
+      ** an equal number of appearances.  Without STAT4 data, we still want
+      ** to use an index in that case, since the constraint might be for
+      ** the scarcer of the two values, and in that case an index lookup is
+      ** better.
+      */
+#ifdef SQLITE_ENABLE_STAT4
+      pNew->rRun = rSize + 16 - 2*((pTab->tabFlags & TF_HasStat4)!=0);
+#else
+      pNew->rRun = rSize + 16;
+#endif
+      ApplyCostMultiplier(pNew->rRun, pTab->costMult);
+      whereLoopOutputAdjust(pWC, pNew, rSize);
+      if( pSrc->fg.isSubquery ){
+        if( pSrc->fg.viaCoroutine ) pNew->wsFlags |= WHERE_COROUTINE;
+        pNew->u.btree.pOrderBy = pSrc->u4.pSubq->pSelect->pOrderBy;
+      }
+      rc = whereLoopInsert(pBuilder, pNew);
+      pNew->nOut = rSize;
+      if( rc ) break;
+    }else{
+      Bitmask m;
+      if( pProbe->isCovering ){
+        m = 0;
+        pNew->wsFlags = WHERE_IDX_ONLY | WHERE_INDEXED;
+      }else{
+        m = pSrc->colUsed & pProbe->colNotIdxed;
+        if( pProbe->pPartIdxWhere ){
+          wherePartIdxExpr(
+              pWInfo->pParse, pProbe, pProbe->pPartIdxWhere, &m, 0, 0
+          );
+        }
+        pNew->wsFlags = WHERE_INDEXED;
+        if( m==TOPBIT || (pProbe->bHasExpr && !pProbe->bHasVCol && m!=0) ){
+          u32 isCov = whereIsCoveringIndex(pWInfo, pProbe, pSrc->iCursor);
+          if( isCov==0 ){
+            WHERETRACE(0x200,
+               ("-> %s is not a covering index"
+                " according to whereIsCoveringIndex()\n", pProbe->zName));
+            assert( m!=0 );
+          }else{
+            m = 0;
+            pNew->wsFlags |= isCov;
+            if( isCov & WHERE_IDX_ONLY ){
+              WHERETRACE(0x200,
+                 ("-> %s is a covering expression index"
+                  " according to whereIsCoveringIndex()\n", pProbe->zName));
+            }else{
+              assert( isCov==WHERE_EXPRIDX );
+              WHERETRACE(0x200,
+                 ("-> %s might be a covering expression index"
+                  " according to whereIsCoveringIndex()\n", pProbe->zName));
+            }
+          }
+        }else if( m==0
+           && (HasRowid(pTab) || pWInfo->pSelect!=0 || sqlite3FaultSim(700))
+        ){
+          WHERETRACE(0x200,
+             ("-> %s a covering index according to bitmasks\n",
+             pProbe->zName, m==0 ? "is" : "is not"));
+          pNew->wsFlags = WHERE_IDX_ONLY | WHERE_INDEXED;
+        }
+      }
+
+      /* Full scan via index */
+      if( b
+       || !HasRowid(pTab)
+       || pProbe->pPartIdxWhere!=0
+       || pSrc->fg.isIndexedBy
+       || ( m==0
+         && pProbe->bUnordered==0
+         && (pProbe->szIdxRow<pTab->szTabRow)
+         && (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0
+         && sqlite3GlobalConfig.bUseCis
+         && OptimizationEnabled(pWInfo->pParse->db, SQLITE_CoverIdxScan)
+          )
+      ){
+        pNew->iSortIdx = b ? iSortIdx : 0;
+
+        /* The cost of visiting the index rows is N*K, where K is
+        ** between 1.1 and 3.0, depending on the relative sizes of the
+        ** index and table rows. */
+        pNew->rRun = rSize + 1 + (15*pProbe->szIdxRow)/pTab->szTabRow;
+        if( m!=0 ){
+          /* If this is a non-covering index scan, add in the cost of
+          ** doing table lookups.  The cost will be 3x the number of
+          ** lookups.  Take into account WHERE clause terms that can be
+          ** satisfied using just the index, and that do not require a
+          ** table lookup. */
+          LogEst nLookup = rSize + 16;  /* Base cost:  N*3 */
+          int ii;
+          int iCur = pSrc->iCursor;
+          WhereClause *pWC2 = &pWInfo->sWC;
+          for(ii=0; ii<pWC2->nTerm; ii++){
+            WhereTerm *pTerm = &pWC2->a[ii];
+            if( !sqlite3ExprCoveredByIndex(pTerm->pExpr, iCur, pProbe) ){
+              break;
+            }
+            /* pTerm can be evaluated using just the index.  So reduce
+            ** the expected number of table lookups accordingly */
+            if( pTerm->truthProb<=0 ){
+              nLookup += pTerm->truthProb;
+            }else{
+              nLookup--;
+              if( pTerm->eOperator & (WO_EQ|WO_IS) ) nLookup -= 19;
+            }
+          }
+
+          pNew->rRun = sqlite3LogEstAdd(pNew->rRun, nLookup);
+        }
+        ApplyCostMultiplier(pNew->rRun, pTab->costMult);
+        whereLoopOutputAdjust(pWC, pNew, rSize);
+        if( (pSrc->fg.jointype & JT_RIGHT)!=0 && pProbe->aColExpr ){
+          /* Do not do an SCAN of a index-on-expression in a RIGHT JOIN
+          ** because the cursor used to access the index might not be
+          ** positioned to the correct row during the right-join no-match
+          ** loop. */
+        }else{
+          rc = whereLoopInsert(pBuilder, pNew);
+        }
+        pNew->nOut = rSize;
+        if( rc ) break;
+      }
+    }
+
+    pBuilder->bldFlags1 = 0;
+    rc = whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, 0);
+    if( pBuilder->bldFlags1==SQLITE_BLDF1_INDEXED ){
+      /* If a non-unique index is used, or if a prefix of the key for
+      ** unique index is used (making the index functionally non-unique)
+      ** then the sqlite_stat1 data becomes important for scoring the
+      ** plan */
+      pTab->tabFlags |= TF_MaybeReanalyze;
+    }
+#ifdef SQLITE_ENABLE_STAT4
+    sqlite3Stat4ProbeFree(pBuilder->pRec);
+    pBuilder->nRecValid = 0;
+    pBuilder->pRec = 0;
+#endif
+  }
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+
+/*
+** Return true if pTerm is a virtual table LIMIT or OFFSET term.
+*/
+static int isLimitTerm(WhereTerm *pTerm){
+  assert( pTerm->eOperator==WO_AUX || pTerm->eMatchOp==0 );
+  return pTerm->eMatchOp>=SQLITE_INDEX_CONSTRAINT_LIMIT
+      && pTerm->eMatchOp<=SQLITE_INDEX_CONSTRAINT_OFFSET;
+}
+
+/*
+** Return true if the first nCons constraints in the pUsage array are
+** marked as in-use (have argvIndex>0). False otherwise.
+*/
+static int allConstraintsUsed(
+  struct sqlite3_index_constraint_usage *aUsage,
+  int nCons
+){
+  int ii;
+  for(ii=0; ii<nCons; ii++){
+    if( aUsage[ii].argvIndex<=0 ) return 0;
+  }
+  return 1;
+}
+
+/*
+** Argument pIdxInfo is already populated with all constraints that may
+** be used by the virtual table identified by pBuilder->pNew->iTab. This
+** function marks a subset of those constraints usable, invokes the
+** xBestIndex method and adds the returned plan to pBuilder.
+**
+** A constraint is marked usable if:
+**
+**   * Argument mUsable indicates that its prerequisites are available, and
+**
+**   * It is not one of the operators specified in the mExclude mask passed
+**     as the fourth argument (which in practice is either WO_IN or 0).
+**
+** Argument mPrereq is a mask of tables that must be scanned before the
+** virtual table in question. These are added to the plans prerequisites
+** before it is added to pBuilder.
+**
+** Output parameter *pbIn is set to true if the plan added to pBuilder
+** uses one or more WO_IN terms, or false otherwise.
+*/
+static int whereLoopAddVirtualOne(
+  WhereLoopBuilder *pBuilder,
+  Bitmask mPrereq,                /* Mask of tables that must be used. */
+  Bitmask mUsable,                /* Mask of usable tables */
+  u16 mExclude,                   /* Exclude terms using these operators */
+  sqlite3_index_info *pIdxInfo,   /* Populated object for xBestIndex */
+  u16 mNoOmit,                    /* Do not omit these constraints */
+  int *pbIn,                      /* OUT: True if plan uses an IN(...) op */
+  int *pbRetryLimit               /* OUT: Retry without LIMIT/OFFSET */
+){
+  WhereClause *pWC = pBuilder->pWC;
+  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  struct sqlite3_index_constraint *pIdxCons;
+  struct sqlite3_index_constraint_usage *pUsage = pIdxInfo->aConstraintUsage;
+  int i;
+  int mxTerm;
+  int rc = SQLITE_OK;
+  WhereLoop *pNew = pBuilder->pNew;
+  Parse *pParse = pBuilder->pWInfo->pParse;
+  SrcItem *pSrc = &pBuilder->pWInfo->pTabList->a[pNew->iTab];
+  int nConstraint = pIdxInfo->nConstraint;
+
+  assert( (mUsable & mPrereq)==mPrereq );
+  *pbIn = 0;
+  pNew->prereq = mPrereq;
+
+  /* Set the usable flag on the subset of constraints identified by
+  ** arguments mUsable and mExclude. */
+  pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
+  for(i=0; i<nConstraint; i++, pIdxCons++){
+    WhereTerm *pTerm = termFromWhereClause(pWC, pIdxCons->iTermOffset);
+    pIdxCons->usable = 0;
+    if( (pTerm->prereqRight & mUsable)==pTerm->prereqRight
+     && (pTerm->eOperator & mExclude)==0
+     && (pbRetryLimit || !isLimitTerm(pTerm))
+    ){
+      pIdxCons->usable = 1;
+    }
+  }
+
+  /* Initialize the output fields of the sqlite3_index_info structure */
+  memset(pUsage, 0, sizeof(pUsage[0])*nConstraint);
+  assert( pIdxInfo->needToFreeIdxStr==0 );
+  pIdxInfo->idxStr = 0;
+  pIdxInfo->idxNum = 0;
+  pIdxInfo->orderByConsumed = 0;
+  pIdxInfo->estimatedCost = SQLITE_BIG_DBL / (double)2;
+  pIdxInfo->estimatedRows = 25;
+  pIdxInfo->idxFlags = 0;
+  pHidden->mHandleIn = 0;
+
+  /* Invoke the virtual table xBestIndex() method */
+  rc = vtabBestIndex(pParse, pSrc->pSTab, pIdxInfo);
+  if( rc ){
+    if( rc==SQLITE_CONSTRAINT ){
+      /* If the xBestIndex method returns SQLITE_CONSTRAINT, that means
+      ** that the particular combination of parameters provided is unusable.
+      ** Make no entries in the loop table.
+      */
+      WHERETRACE(0xffffffff, ("  ^^^^--- non-viable plan rejected!\n"));
+      freeIdxStr(pIdxInfo);
+      return SQLITE_OK;
+    }
+    return rc;
+  }
+
+  mxTerm = -1;
+  assert( pNew->nLSlot>=nConstraint );
+  memset(pNew->aLTerm, 0, sizeof(pNew->aLTerm[0])*nConstraint );
+  memset(&pNew->u.vtab, 0, sizeof(pNew->u.vtab));
+  pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
+  for(i=0; i<nConstraint; i++, pIdxCons++){
+    int iTerm;
+    if( (iTerm = pUsage[i].argvIndex - 1)>=0 ){
+      WhereTerm *pTerm;
+      int j = pIdxCons->iTermOffset;
+      if( iTerm>=nConstraint
+       || j<0
+       || (pTerm = termFromWhereClause(pWC, j))==0
+       || pNew->aLTerm[iTerm]!=0
+       || pIdxCons->usable==0
+      ){
+        sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pSTab->zName);
+        freeIdxStr(pIdxInfo);
+        return SQLITE_ERROR;
+      }
+      testcase( iTerm==nConstraint-1 );
+      testcase( j==0 );
+      testcase( j==pWC->nTerm-1 );
+      pNew->prereq |= pTerm->prereqRight;
+      assert( iTerm<pNew->nLSlot );
+      pNew->aLTerm[iTerm] = pTerm;
+      if( iTerm>mxTerm ) mxTerm = iTerm;
+      testcase( iTerm==15 );
+      testcase( iTerm==16 );
+      if( pUsage[i].omit ){
+        if( i<16 && ((1<<i)&mNoOmit)==0 ){
+          testcase( i!=iTerm );
+          pNew->u.vtab.omitMask |= 1<<iTerm;
+        }else{
+          testcase( i!=iTerm );
+        }
+        if( pTerm->eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET ){
+          pNew->u.vtab.bOmitOffset = 1;
+        }
+      }
+      if( SMASKBIT32(i) & pHidden->mHandleIn ){
+        pNew->u.vtab.mHandleIn |= MASKBIT32(iTerm);
+      }else if( (pTerm->eOperator & WO_IN)!=0 ){
+        /* A virtual table that is constrained by an IN clause may not
+        ** consume the ORDER BY clause because (1) the order of IN terms
+        ** is not necessarily related to the order of output terms and
+        ** (2) Multiple outputs from a single IN value will not merge
+        ** together.  */
+        pIdxInfo->orderByConsumed = 0;
+        pIdxInfo->idxFlags &= ~SQLITE_INDEX_SCAN_UNIQUE;
+        *pbIn = 1; assert( (mExclude & WO_IN)==0 );
+      }
+
+      /* Unless pbRetryLimit is non-NULL, there should be no LIMIT/OFFSET
+      ** terms. And if there are any, they should follow all other terms. */
+      assert( pbRetryLimit || !isLimitTerm(pTerm) );
+      assert( !isLimitTerm(pTerm) || i>=nConstraint-2 );
+      assert( !isLimitTerm(pTerm) || i==nConstraint-1 || isLimitTerm(pTerm+1) );
+
+      if( isLimitTerm(pTerm) && (*pbIn || !allConstraintsUsed(pUsage, i)) ){
+        /* If there is an IN(...) term handled as an == (separate call to
+        ** xFilter for each value on the RHS of the IN) and a LIMIT or
+        ** OFFSET term handled as well, the plan is unusable. Similarly,
+        ** if there is a LIMIT/OFFSET and there are other unused terms,
+        ** the plan cannot be used. In these cases set variable *pbRetryLimit
+        ** to true to tell the caller to retry with LIMIT and OFFSET
+        ** disabled. */
+        freeIdxStr(pIdxInfo);
+        *pbRetryLimit = 1;
+        return SQLITE_OK;
+      }
+    }
+  }
+
+  pNew->nLTerm = mxTerm+1;
+  for(i=0; i<=mxTerm; i++){
+    if( pNew->aLTerm[i]==0 ){
+      /* The non-zero argvIdx values must be contiguous.  Raise an
+      ** error if they are not */
+      sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pSTab->zName);
+      freeIdxStr(pIdxInfo);
+      return SQLITE_ERROR;
+    }
+  }
+  assert( pNew->nLTerm<=pNew->nLSlot );
+  pNew->u.vtab.idxNum = pIdxInfo->idxNum;
+  pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
+  pIdxInfo->needToFreeIdxStr = 0;
+  pNew->u.vtab.idxStr = pIdxInfo->idxStr;
+  pNew->u.vtab.isOrdered = (i8)(pIdxInfo->orderByConsumed ?
+      pIdxInfo->nOrderBy : 0);
+  pNew->u.vtab.bIdxNumHex = (pIdxInfo->idxFlags&SQLITE_INDEX_SCAN_HEX)!=0;
+  pNew->rSetup = 0;
+  pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost);
+  pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows);
+
+  /* Set the WHERE_ONEROW flag if the xBestIndex() method indicated
+  ** that the scan will visit at most one row. Clear it otherwise. */
+  if( pIdxInfo->idxFlags & SQLITE_INDEX_SCAN_UNIQUE ){
+    pNew->wsFlags |= WHERE_ONEROW;
+  }else{
+    pNew->wsFlags &= ~WHERE_ONEROW;
+  }
+  rc = whereLoopInsert(pBuilder, pNew);
+  if( pNew->u.vtab.needFree ){
+    sqlite3_free(pNew->u.vtab.idxStr);
+    pNew->u.vtab.needFree = 0;
+  }
+  WHERETRACE(0xffffffff, ("  bIn=%d prereqIn=%04llx prereqOut=%04llx\n",
+                      *pbIn, (sqlite3_uint64)mPrereq,
+                      (sqlite3_uint64)(pNew->prereq & ~mPrereq)));
+
+  return rc;
+}
+
+/*
+** Return the collating sequence for a constraint passed into xBestIndex.
+**
+** pIdxInfo must be an sqlite3_index_info structure passed into xBestIndex.
+** This routine depends on there being a HiddenIndexInfo structure immediately
+** following the sqlite3_index_info structure.
+**
+** Return a pointer to the collation name:
+**
+**    1. If there is an explicit COLLATE operator on the constraint, return it.
+**
+**    2. Else, if the column has an alternative collation, return that.
+**
+**    3. Otherwise, return "BINARY".
+*/
+SQLITE_API const char *sqlite3_vtab_collation(sqlite3_index_info *pIdxInfo, int iCons){
+  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  const char *zRet = 0;
+  if( iCons>=0 && iCons<pIdxInfo->nConstraint ){
+    CollSeq *pC = 0;
+    int iTerm = pIdxInfo->aConstraint[iCons].iTermOffset;
+    Expr *pX = termFromWhereClause(pHidden->pWC, iTerm)->pExpr;
+    if( pX->pLeft ){
+      pC = sqlite3ExprCompareCollSeq(pHidden->pParse, pX);
+    }
+    zRet = (pC ? pC->zName : sqlite3StrBINARY);
+  }
+  return zRet;
+}
+
+/*
+** Return true if constraint iCons is really an IN(...) constraint, or
+** false otherwise. If iCons is an IN(...) constraint, set (if bHandle!=0)
+** or clear (if bHandle==0) the flag to handle it using an iterator.
+*/
+SQLITE_API int sqlite3_vtab_in(sqlite3_index_info *pIdxInfo, int iCons, int bHandle){
+  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  u32 m = SMASKBIT32(iCons);
+  if( m & pHidden->mIn ){
+    if( bHandle==0 ){
+      pHidden->mHandleIn &= ~m;
+    }else if( bHandle>0 ){
+      pHidden->mHandleIn |= m;
+    }
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** This interface is callable from within the xBestIndex callback only.
+**
+** If possible, set (*ppVal) to point to an object containing the value
+** on the right-hand-side of constraint iCons.
+*/
+SQLITE_API int sqlite3_vtab_rhs_value(
+  sqlite3_index_info *pIdxInfo,   /* Copy of first argument to xBestIndex */
+  int iCons,                      /* Constraint for which RHS is wanted */
+  sqlite3_value **ppVal           /* Write value extracted here */
+){
+  HiddenIndexInfo *pH = (HiddenIndexInfo*)&pIdxInfo[1];
+  sqlite3_value *pVal = 0;
+  int rc = SQLITE_OK;
+  if( iCons<0 || iCons>=pIdxInfo->nConstraint ){
+    rc = SQLITE_MISUSE_BKPT; /* EV: R-30545-25046 */
+  }else{
+    if( pH->aRhs[iCons]==0 ){
+      WhereTerm *pTerm = termFromWhereClause(
+          pH->pWC, pIdxInfo->aConstraint[iCons].iTermOffset
+      );
+      rc = sqlite3ValueFromExpr(
+          pH->pParse->db, pTerm->pExpr->pRight, ENC(pH->pParse->db),
+          SQLITE_AFF_BLOB, &pH->aRhs[iCons]
+      );
+      testcase( rc!=SQLITE_OK );
+    }
+    pVal = pH->aRhs[iCons];
+  }
+  *ppVal = pVal;
+
+  if( rc==SQLITE_OK && pVal==0 ){  /* IMP: R-19933-32160 */
+    rc = SQLITE_NOTFOUND;          /* IMP: R-36424-56542 */
+  }
+
+  return rc;
+}
+
+/*
+** Return true if ORDER BY clause may be handled as DISTINCT.
+*/
+SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info *pIdxInfo){
+  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  assert( pHidden->eDistinct>=0 && pHidden->eDistinct<=3 );
+  return pHidden->eDistinct;
+}
+
+/*
+** Cause the prepared statement that is associated with a call to
+** xBestIndex to potentially use all schemas.  If the statement being
+** prepared is read-only, then just start read transactions on all
+** schemas.  But if this is a write operation, start writes on all
+** schemas.
+**
+** This is used by the (built-in) sqlite_dbpage virtual table.
+*/
+SQLITE_PRIVATE void sqlite3VtabUsesAllSchemas(Parse *pParse){
+  int nDb = pParse->db->nDb;
+  int i;
+  for(i=0; i<nDb; i++){
+    sqlite3CodeVerifySchema(pParse, i);
+  }
+  if( DbMaskNonZero(pParse->writeMask) ){
+    for(i=0; i<nDb; i++){
+      sqlite3BeginWriteOperation(pParse, 0, i);
+    }
+  }
+}
+
+/*
+** Add all WhereLoop objects for a table of the join identified by
+** pBuilder->pNew->iTab.  That table is guaranteed to be a virtual table.
+**
+** If there are no LEFT or CROSS JOIN joins in the query, both mPrereq and
+** mUnusable are set to 0. Otherwise, mPrereq is a mask of all FROM clause
+** entries that occur before the virtual table in the FROM clause and are
+** separated from it by at least one LEFT or CROSS JOIN. Similarly, the
+** mUnusable mask contains all FROM clause entries that occur after the
+** virtual table and are separated from it by at least one LEFT or
+** CROSS JOIN.
+**
+** For example, if the query were:
+**
+**   ... FROM t1, t2 LEFT JOIN t3, t4, vt CROSS JOIN t5, t6;
+**
+** then mPrereq corresponds to (t1, t2) and mUnusable to (t5, t6).
+**
+** All the tables in mPrereq must be scanned before the current virtual
+** table. So any terms for which all prerequisites are satisfied by
+** mPrereq may be specified as "usable" in all calls to xBestIndex.
+** Conversely, all tables in mUnusable must be scanned after the current
+** virtual table, so any terms for which the prerequisites overlap with
+** mUnusable should always be configured as "not-usable" for xBestIndex.
+*/
+static int whereLoopAddVirtual(
+  WhereLoopBuilder *pBuilder,  /* WHERE clause information */
+  Bitmask mPrereq,             /* Tables that must be scanned before this one */
+  Bitmask mUnusable            /* Tables that must be scanned after this one */
+){
+  int rc = SQLITE_OK;          /* Return code */
+  WhereInfo *pWInfo;           /* WHERE analysis context */
+  Parse *pParse;               /* The parsing context */
+  WhereClause *pWC;            /* The WHERE clause */
+  SrcItem *pSrc;               /* The FROM clause term to search */
+  sqlite3_index_info *p;       /* Object to pass to xBestIndex() */
+  int nConstraint;             /* Number of constraints in p */
+  int bIn;                     /* True if plan uses IN(...) operator */
+  WhereLoop *pNew;
+  Bitmask mBest;               /* Tables used by best possible plan */
+  u16 mNoOmit;
+  int bRetry = 0;              /* True to retry with LIMIT/OFFSET disabled */
+
+  assert( (mPrereq & mUnusable)==0 );
+  pWInfo = pBuilder->pWInfo;
+  pParse = pWInfo->pParse;
+  pWC = pBuilder->pWC;
+  pNew = pBuilder->pNew;
+  pSrc = &pWInfo->pTabList->a[pNew->iTab];
+  assert( IsVirtual(pSrc->pSTab) );
+  p = allocateIndexInfo(pWInfo, pWC, mUnusable, pSrc, &mNoOmit);
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  pNew->rSetup = 0;
+  pNew->wsFlags = WHERE_VIRTUALTABLE;
+  pNew->nLTerm = 0;
+  pNew->u.vtab.needFree = 0;
+  nConstraint = p->nConstraint;
+  if( whereLoopResize(pParse->db, pNew, nConstraint) ){
+    freeIndexInfo(pParse->db, p);
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  /* First call xBestIndex() with all constraints usable. */
+  WHERETRACE(0x800, ("BEGIN %s.addVirtual()\n", pSrc->pSTab->zName));
+  WHERETRACE(0x800, ("  VirtualOne: all usable\n"));
+  rc = whereLoopAddVirtualOne(
+      pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn, &bRetry
+  );
+  if( bRetry ){
+    assert( rc==SQLITE_OK );
+    rc = whereLoopAddVirtualOne(
+        pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn, 0
+    );
+  }
+
+  /* If the call to xBestIndex() with all terms enabled produced a plan
+  ** that does not require any source tables (IOW: a plan with mBest==0)
+  ** and does not use an IN(...) operator, then there is no point in making
+  ** any further calls to xBestIndex() since they will all return the same
+  ** result (if the xBestIndex() implementation is sane). */
+  if( rc==SQLITE_OK && ((mBest = (pNew->prereq & ~mPrereq))!=0 || bIn) ){
+    int seenZero = 0;             /* True if a plan with no prereqs seen */
+    int seenZeroNoIN = 0;         /* Plan with no prereqs and no IN(...) seen */
+    Bitmask mPrev = 0;
+    Bitmask mBestNoIn = 0;
+
+    /* If the plan produced by the earlier call uses an IN(...) term, call
+    ** xBestIndex again, this time with IN(...) terms disabled. */
+    if( bIn ){
+      WHERETRACE(0x800, ("  VirtualOne: all usable w/o IN\n"));
+      rc = whereLoopAddVirtualOne(
+          pBuilder, mPrereq, ALLBITS, WO_IN, p, mNoOmit, &bIn, 0);
+      assert( bIn==0 );
+      mBestNoIn = pNew->prereq & ~mPrereq;
+      if( mBestNoIn==0 ){
+        seenZero = 1;
+        seenZeroNoIN = 1;
+      }
+    }
+
+    /* Call xBestIndex once for each distinct value of (prereqRight & ~mPrereq)
+    ** in the set of terms that apply to the current virtual table.  */
+    while( rc==SQLITE_OK ){
+      int i;
+      Bitmask mNext = ALLBITS;
+      assert( mNext>0 );
+      for(i=0; i<nConstraint; i++){
+        int iTerm = p->aConstraint[i].iTermOffset;
+        Bitmask mThis = termFromWhereClause(pWC, iTerm)->prereqRight & ~mPrereq;
+        if( mThis>mPrev && mThis<mNext ) mNext = mThis;
+      }
+      mPrev = mNext;
+      if( mNext==ALLBITS ) break;
+      if( mNext==mBest || mNext==mBestNoIn ) continue;
+      WHERETRACE(0x800, ("  VirtualOne: mPrev=%04llx mNext=%04llx\n",
+                       (sqlite3_uint64)mPrev, (sqlite3_uint64)mNext));
+      rc = whereLoopAddVirtualOne(
+          pBuilder, mPrereq, mNext|mPrereq, 0, p, mNoOmit, &bIn, 0);
+      if( pNew->prereq==mPrereq ){
+        seenZero = 1;
+        if( bIn==0 ) seenZeroNoIN = 1;
+      }
+    }
+
+    /* If the calls to xBestIndex() in the above loop did not find a plan
+    ** that requires no source tables at all (i.e. one guaranteed to be
+    ** usable), make a call here with all source tables disabled */
+    if( rc==SQLITE_OK && seenZero==0 ){
+      WHERETRACE(0x800, ("  VirtualOne: all disabled\n"));
+      rc = whereLoopAddVirtualOne(
+          pBuilder, mPrereq, mPrereq, 0, p, mNoOmit, &bIn, 0);
+      if( bIn==0 ) seenZeroNoIN = 1;
+    }
+
+    /* If the calls to xBestIndex() have so far failed to find a plan
+    ** that requires no source tables at all and does not use an IN(...)
+    ** operator, make a final call to obtain one here.  */
+    if( rc==SQLITE_OK && seenZeroNoIN==0 ){
+      WHERETRACE(0x800, ("  VirtualOne: all disabled and w/o IN\n"));
+      rc = whereLoopAddVirtualOne(
+          pBuilder, mPrereq, mPrereq, WO_IN, p, mNoOmit, &bIn, 0);
+    }
+  }
+
+  freeIndexInfo(pParse->db, p);
+  WHERETRACE(0x800, ("END %s.addVirtual(), rc=%d\n", pSrc->pSTab->zName, rc));
+  return rc;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** Add WhereLoop entries to handle OR terms.  This works for either
+** btrees or virtual tables.
+*/
+static int whereLoopAddOr(
+  WhereLoopBuilder *pBuilder,
+  Bitmask mPrereq,
+  Bitmask mUnusable
+){
+  WhereInfo *pWInfo = pBuilder->pWInfo;
+  WhereClause *pWC;
+  WhereLoop *pNew;
+  WhereTerm *pTerm, *pWCEnd;
+  int rc = SQLITE_OK;
+  int iCur;
+  WhereClause tempWC;
+  WhereLoopBuilder sSubBuild;
+  WhereOrSet sSum, sCur;
+  SrcItem *pItem;
+
+  pWC = pBuilder->pWC;
+  pWCEnd = pWC->a + pWC->nTerm;
+  pNew = pBuilder->pNew;
+  memset(&sSum, 0, sizeof(sSum));
+  pItem = pWInfo->pTabList->a + pNew->iTab;
+  iCur = pItem->iCursor;
+
+  /* The multi-index OR optimization does not work for RIGHT and FULL JOIN */
+  if( pItem->fg.jointype & JT_RIGHT ) return SQLITE_OK;
+
+  for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE_OK; pTerm++){
+    if( (pTerm->eOperator & WO_OR)!=0
+     && (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0
+    ){
+      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
+      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
+      WhereTerm *pOrTerm;
+      int once = 1;
+      int i, j;
+
+      sSubBuild = *pBuilder;
+      sSubBuild.pOrSet = &sCur;
+
+      WHERETRACE(0x400, ("Begin processing OR-clause %p\n", pTerm));
+      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
+        if( (pOrTerm->eOperator & WO_AND)!=0 ){
+          sSubBuild.pWC = &pOrTerm->u.pAndInfo->wc;
+        }else if( pOrTerm->leftCursor==iCur ){
+          tempWC.pWInfo = pWC->pWInfo;
+          tempWC.pOuter = pWC;
+          tempWC.op = TK_AND;
+          tempWC.nTerm = 1;
+          tempWC.nBase = 1;
+          tempWC.a = pOrTerm;
+          sSubBuild.pWC = &tempWC;
+        }else{
+          continue;
+        }
+        sCur.n = 0;
+#ifdef WHERETRACE_ENABLED
+        WHERETRACE(0x400, ("OR-term %d of %p has %d subterms:\n",
+                   (int)(pOrTerm-pOrWC->a), pTerm, sSubBuild.pWC->nTerm));
+        if( sqlite3WhereTrace & 0x20000 ){
+          sqlite3WhereClausePrint(sSubBuild.pWC);
+        }
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+        if( IsVirtual(pItem->pSTab) ){
+          rc = whereLoopAddVirtual(&sSubBuild, mPrereq, mUnusable);
+        }else
+#endif
+        {
+          rc = whereLoopAddBtree(&sSubBuild, mPrereq);
+        }
+        if( rc==SQLITE_OK ){
+          rc = whereLoopAddOr(&sSubBuild, mPrereq, mUnusable);
+        }
+        testcase( rc==SQLITE_NOMEM && sCur.n>0 );
+        testcase( rc==SQLITE_DONE );
+        if( sCur.n==0 ){
+          sSum.n = 0;
+          break;
+        }else if( once ){
+          whereOrMove(&sSum, &sCur);
+          once = 0;
+        }else{
+          WhereOrSet sPrev;
+          whereOrMove(&sPrev, &sSum);
+          sSum.n = 0;
+          for(i=0; i<sPrev.n; i++){
+            for(j=0; j<sCur.n; j++){
+              whereOrInsert(&sSum, sPrev.a[i].prereq | sCur.a[j].prereq,
+                            sqlite3LogEstAdd(sPrev.a[i].rRun, sCur.a[j].rRun),
+                            sqlite3LogEstAdd(sPrev.a[i].nOut, sCur.a[j].nOut));
+            }
+          }
+        }
+      }
+      pNew->nLTerm = 1;
+      pNew->aLTerm[0] = pTerm;
+      pNew->wsFlags = WHERE_MULTI_OR;
+      pNew->rSetup = 0;
+      pNew->iSortIdx = 0;
+      memset(&pNew->u, 0, sizeof(pNew->u));
+      for(i=0; rc==SQLITE_OK && i<sSum.n; i++){
+        /* TUNING: Currently sSum.a[i].rRun is set to the sum of the costs
+        ** of all sub-scans required by the OR-scan. However, due to rounding
+        ** errors, it may be that the cost of the OR-scan is equal to its
+        ** most expensive sub-scan. Add the smallest possible penalty
+        ** (equivalent to multiplying the cost by 1.07) to ensure that
+        ** this does not happen. Otherwise, for WHERE clauses such as the
+        ** following where there is an index on "y":
+        **
+        **     WHERE likelihood(x=?, 0.99) OR y=?
+        **
+        ** the planner may elect to "OR" together a full-table scan and an
+        ** index lookup. And other similarly odd results.  */
+        pNew->rRun = sSum.a[i].rRun + 1;
+        pNew->nOut = sSum.a[i].nOut;
+        pNew->prereq = sSum.a[i].prereq;
+        rc = whereLoopInsert(pBuilder, pNew);
+      }
+      WHERETRACE(0x400, ("End processing OR-clause %p\n", pTerm));
+    }
+  }
+  return rc;
+}
+
+/*
+** Add all WhereLoop objects for all tables
+*/
+static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
+  WhereInfo *pWInfo = pBuilder->pWInfo;
+  Bitmask mPrereq = 0;
+  Bitmask mPrior = 0;
+  int iTab;
+  SrcList *pTabList = pWInfo->pTabList;
+  SrcItem *pItem;
+  SrcItem *pEnd = &pTabList->a[pWInfo->nLevel];
+  sqlite3 *db = pWInfo->pParse->db;
+  int rc = SQLITE_OK;
+  int bFirstPastRJ = 0;
+  int hasRightJoin = 0;
+  WhereLoop *pNew;
+
+
+  /* Loop over the tables in the join, from left to right */
+  pNew = pBuilder->pNew;
+
+  /* Verify that pNew has already been initialized */
+  assert( pNew->nLTerm==0 );
+  assert( pNew->wsFlags==0 );
+  assert( pNew->nLSlot>=ArraySize(pNew->aLTermSpace) );
+  assert( pNew->aLTerm!=0 );
+
+  pBuilder->iPlanLimit = SQLITE_QUERY_PLANNER_LIMIT;
+  for(iTab=0, pItem=pTabList->a; pItem<pEnd; iTab++, pItem++){
+    Bitmask mUnusable = 0;
+    pNew->iTab = iTab;
+    pBuilder->iPlanLimit += SQLITE_QUERY_PLANNER_LIMIT_INCR;
+    pNew->maskSelf = sqlite3WhereGetMask(&pWInfo->sMaskSet, pItem->iCursor);
+    if( bFirstPastRJ
+     || (pItem->fg.jointype & (JT_OUTER|JT_CROSS|JT_LTORJ))!=0
+    ){
+      /* Add prerequisites to prevent reordering of FROM clause terms
+      ** across CROSS joins and outer joins.  The bFirstPastRJ boolean
+      ** prevents the right operand of a RIGHT JOIN from being swapped with
+      ** other elements even further to the right.
+      **
+      ** The JT_LTORJ case and the hasRightJoin flag work together to
+      ** prevent FROM-clause terms from moving from the right side of
+      ** a LEFT JOIN over to the left side of that join if the LEFT JOIN
+      ** is itself on the left side of a RIGHT JOIN.
+      */
+      if( pItem->fg.jointype & JT_LTORJ ) hasRightJoin = 1;
+      mPrereq |= mPrior;
+      bFirstPastRJ = (pItem->fg.jointype & JT_RIGHT)!=0;
+    }else if( !hasRightJoin ){
+      mPrereq = 0;
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( IsVirtual(pItem->pSTab) ){
+      SrcItem *p;
+      for(p=&pItem[1]; p<pEnd; p++){
+        if( mUnusable || (p->fg.jointype & (JT_OUTER|JT_CROSS)) ){
+          mUnusable |= sqlite3WhereGetMask(&pWInfo->sMaskSet, p->iCursor);
+        }
+      }
+      rc = whereLoopAddVirtual(pBuilder, mPrereq, mUnusable);
+    }else
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+    {
+      rc = whereLoopAddBtree(pBuilder, mPrereq);
+    }
+    if( rc==SQLITE_OK && pBuilder->pWC->hasOr ){
+      rc = whereLoopAddOr(pBuilder, mPrereq, mUnusable);
+    }
+    mPrior |= pNew->maskSelf;
+    if( rc || db->mallocFailed ){
+      if( rc==SQLITE_DONE ){
+        /* We hit the query planner search limit set by iPlanLimit */
+        sqlite3_log(SQLITE_WARNING, "abbreviated query algorithm search");
+        rc = SQLITE_OK;
+      }else{
+        break;
+      }
+    }
+  }
+
+  whereLoopClear(db, pNew);
+  return rc;
+}
+
+/* Implementation of the order-by-subquery optimization:
+**
+** WhereLoop pLoop, which the iLoop-th term of the nested loop, is really
+** a subquery or CTE that has an ORDER BY clause.  See if any of the terms
+** in the subquery ORDER BY clause will satisfy pOrderBy from the outer
+** query.  Mark off all satisfied terms (by setting bits in *pOBSat) and
+** return TRUE if they do.  If not, return false.
+**
+** Example:
+**
+**    CREATE TABLE t1(a,b,c, PRIMARY KEY(a,b));
+**    CREATE TABLE t2(x,y);
+**    WITH t3(p,q) AS MATERIALIZED (SELECT x+y, x-y FROM t2 ORDER BY x+y)
+**       SELECT * FROM t3 JOIN t1 ON a=q ORDER BY p, b;
+**
+** The CTE named "t3" comes out in the natural order of "p", so the first
+** first them of "ORDER BY p,b" is satisfied by a sequential scan of "t3"
+** and sorting only needs to occur on the second term "b".
+**
+** Limitations:
+**
+** (1)  The optimization is not applied if the outer ORDER BY contains
+**      a COLLATE clause.  The optimization might be applied if the
+**      outer ORDER BY uses NULLS FIRST, NULLS LAST, ASC, and/or DESC as
+**      long as the subquery ORDER BY does the same.  But if the
+**      outer ORDER BY uses COLLATE, even a redundant COLLATE, the
+**      optimization is bypassed.
+**
+** (2)  The subquery ORDER BY terms must exactly match subquery result
+**      columns, including any COLLATE annotations.  This routine relies
+**      on iOrderByCol to do matching between order by terms and result
+**      columns, and iOrderByCol will not be set if the result column
+**      and ORDER BY collations differ.
+**
+** (3)  The subquery and outer ORDER BY can be in opposite directions as
+**      long as  the subquery is materialized.  If the subquery is
+**      implemented as a co-routine, the sort orders must be in the same
+**      direction because there is no way to run a co-routine backwards.
+*/
+static SQLITE_NOINLINE int wherePathMatchSubqueryOB(
+  WhereInfo *pWInfo,      /* The WHERE clause */
+  WhereLoop *pLoop,       /* The nested loop term that is a subquery */
+  int iLoop,              /* Which level of the nested loop.  0==outermost */
+  int iCur,               /* Cursor used by the this loop */
+  ExprList *pOrderBy,     /* The ORDER BY clause on the whole query */
+  Bitmask *pRevMask,      /* When loops need to go in reverse order */
+  Bitmask *pOBSat         /* Which terms of pOrderBy are satisfied so far */
+){
+  int iOB;                /* Index into pOrderBy->a[] */
+  int jSub;               /* Index into pSubOB->a[] */
+  u8 rev = 0;             /* True if iOB and jSub sort in opposite directions */
+  u8 revIdx = 0;          /* Sort direction for jSub */
+  Expr *pOBExpr;          /* Current term of outer ORDER BY */
+  ExprList *pSubOB;       /* Complete ORDER BY on the subquery */
+
+  pSubOB = pLoop->u.btree.pOrderBy;
+  assert( pSubOB!=0 );
+  for(iOB=0; (MASKBIT(iOB) & *pOBSat)!=0; iOB++){}
+  for(jSub=0; jSub<pSubOB->nExpr && iOB<pOrderBy->nExpr; jSub++, iOB++){
+    if( pSubOB->a[jSub].u.x.iOrderByCol==0 ) break;
+    pOBExpr = pOrderBy->a[iOB].pExpr;
+    if( pOBExpr->op!=TK_COLUMN && pOBExpr->op!=TK_AGG_COLUMN ) break;
+    if( pOBExpr->iTable!=iCur ) break;
+    if( pOBExpr->iColumn!=pSubOB->a[jSub].u.x.iOrderByCol-1 ) break;
+    if( (pWInfo->wctrlFlags & WHERE_GROUPBY)==0 ){
+      u8 sfOB = pOrderBy->a[iOB].fg.sortFlags;   /* sortFlags for iOB */
+      u8 sfSub = pSubOB->a[jSub].fg.sortFlags;   /* sortFlags for jSub */
+      if( (sfSub & KEYINFO_ORDER_BIGNULL) != (sfOB & KEYINFO_ORDER_BIGNULL) ){
+        break;
+      }
+      revIdx = sfSub & KEYINFO_ORDER_DESC;
+      if( jSub>0 ){
+        if( (rev^revIdx)!=(sfOB & KEYINFO_ORDER_DESC) ){
+          break;
+        }
+      }else{
+        rev = revIdx ^ (sfOB & KEYINFO_ORDER_DESC);
+        if( rev ){
+          if( (pLoop->wsFlags & WHERE_COROUTINE)!=0 ){
+            /* Cannot run a co-routine in reverse order */
+            break;
+          }
+          *pRevMask |= MASKBIT(iLoop);
+        }
+      }
+    }
+    *pOBSat |= MASKBIT(iOB);
+  }
+  return jSub>0;
+}
+
+/*
+** Examine a WherePath (with the addition of the extra WhereLoop of the 6th
+** parameters) to see if it outputs rows in the requested ORDER BY
+** (or GROUP BY) without requiring a separate sort operation.  Return N:
+**
+**   N>0:   N terms of the ORDER BY clause are satisfied
+**   N==0:  No terms of the ORDER BY clause are satisfied
+**   N<0:   Unknown yet how many terms of ORDER BY might be satisfied.
+**
+** Note that processing for WHERE_GROUPBY and WHERE_DISTINCTBY is not as
+** strict.  With GROUP BY and DISTINCT the only requirement is that
+** equivalent rows appear immediately adjacent to one another.  GROUP BY
+** and DISTINCT do not require rows to appear in any particular order as long
+** as equivalent rows are grouped together.  Thus for GROUP BY and DISTINCT
+** the pOrderBy terms can be matched in any order.  With ORDER BY, the
+** pOrderBy terms must be matched in strict left-to-right order.
+*/
+static i8 wherePathSatisfiesOrderBy(
+  WhereInfo *pWInfo,    /* The WHERE clause */
+  ExprList *pOrderBy,   /* ORDER BY or GROUP BY or DISTINCT clause to check */
+  WherePath *pPath,     /* The WherePath to check */
+  u16 wctrlFlags,       /* WHERE_GROUPBY or _DISTINCTBY or _ORDERBY_LIMIT */
+  u16 nLoop,            /* Number of entries in pPath->aLoop[] */
+  WhereLoop *pLast,     /* Add this WhereLoop to the end of pPath->aLoop[] */
+  Bitmask *pRevMask     /* OUT: Mask of WhereLoops to run in reverse order */
+){
+  u8 revSet;            /* True if rev is known */
+  u8 rev;               /* Composite sort order */
+  u8 revIdx;            /* Index sort order */
+  u8 isOrderDistinct;   /* All prior WhereLoops are order-distinct */
+  u8 distinctColumns;   /* True if the loop has UNIQUE NOT NULL columns */
+  u8 isMatch;           /* iColumn matches a term of the ORDER BY clause */
+  u16 eqOpMask;         /* Allowed equality operators */
+  u16 nKeyCol;          /* Number of key columns in pIndex */
+  u16 nColumn;          /* Total number of ordered columns in the index */
+  u16 nOrderBy;         /* Number terms in the ORDER BY clause */
+  int iLoop;            /* Index of WhereLoop in pPath being processed */
+  int i, j;             /* Loop counters */
+  int iCur;             /* Cursor number for current WhereLoop */
+  int iColumn;          /* A column number within table iCur */
+  WhereLoop *pLoop = 0; /* Current WhereLoop being processed. */
+  WhereTerm *pTerm;     /* A single term of the WHERE clause */
+  Expr *pOBExpr;        /* An expression from the ORDER BY clause */
+  CollSeq *pColl;       /* COLLATE function from an ORDER BY clause term */
+  Index *pIndex;        /* The index associated with pLoop */
+  sqlite3 *db = pWInfo->pParse->db;  /* Database connection */
+  Bitmask obSat = 0;    /* Mask of ORDER BY terms satisfied so far */
+  Bitmask obDone;       /* Mask of all ORDER BY terms */
+  Bitmask orderDistinctMask;  /* Mask of all well-ordered loops */
+  Bitmask ready;              /* Mask of inner loops */
+
+  /*
+  ** We say the WhereLoop is "one-row" if it generates no more than one
+  ** row of output.  A WhereLoop is one-row if all of the following are true:
+  **  (a) All index columns match with WHERE_COLUMN_EQ.
+  **  (b) The index is unique
+  ** Any WhereLoop with an WHERE_COLUMN_EQ constraint on the rowid is one-row.
+  ** Every one-row WhereLoop will have the WHERE_ONEROW bit set in wsFlags.
+  **
+  ** We say the WhereLoop is "order-distinct" if the set of columns from
+  ** that WhereLoop that are in the ORDER BY clause are different for every
+  ** row of the WhereLoop.  Every one-row WhereLoop is automatically
+  ** order-distinct.   A WhereLoop that has no columns in the ORDER BY clause
+  ** is not order-distinct. To be order-distinct is not quite the same as being
+  ** UNIQUE since a UNIQUE column or index can have multiple rows that
+  ** are NULL and NULL values are equivalent for the purpose of order-distinct.
+  ** To be order-distinct, the columns must be UNIQUE and NOT NULL.
+  **
+  ** The rowid for a table is always UNIQUE and NOT NULL so whenever the
+  ** rowid appears in the ORDER BY clause, the corresponding WhereLoop is
+  ** automatically order-distinct.
+  */
+
+  assert( pOrderBy!=0 );
+  if( nLoop && OptimizationDisabled(db, SQLITE_OrderByIdxJoin) ) return 0;
+
+  nOrderBy = pOrderBy->nExpr;
+  testcase( nOrderBy==BMS-1 );
+  if( nOrderBy>BMS-1 ) return 0;  /* Cannot optimize overly large ORDER BYs */
+  isOrderDistinct = 1;
+  obDone = MASKBIT(nOrderBy)-1;
+  orderDistinctMask = 0;
+  ready = 0;
+  eqOpMask = WO_EQ | WO_IS | WO_ISNULL;
+  if( wctrlFlags & (WHERE_ORDERBY_LIMIT|WHERE_ORDERBY_MAX|WHERE_ORDERBY_MIN) ){
+    eqOpMask |= WO_IN;
+  }
+  for(iLoop=0; isOrderDistinct && obSat<obDone && iLoop<=nLoop; iLoop++){
+    if( iLoop>0 ) ready |= pLoop->maskSelf;
+    if( iLoop<nLoop ){
+      pLoop = pPath->aLoop[iLoop];
+      if( wctrlFlags & WHERE_ORDERBY_LIMIT ) continue;
+    }else{
+      pLoop = pLast;
+    }
+    if( pLoop->wsFlags & WHERE_VIRTUALTABLE ){
+      if( pLoop->u.vtab.isOrdered
+       && ((wctrlFlags&(WHERE_DISTINCTBY|WHERE_SORTBYGROUP))!=WHERE_DISTINCTBY)
+      ){
+        obSat = obDone;
+      }
+      break;
+    }else if( wctrlFlags & WHERE_DISTINCTBY ){
+      pLoop->u.btree.nDistinctCol = 0;
+    }
+    iCur = pWInfo->pTabList->a[pLoop->iTab].iCursor;
+
+    /* Mark off any ORDER BY term X that is a column in the table of
+    ** the current loop for which there is term in the WHERE
+    ** clause of the form X IS NULL or X=? that reference only outer
+    ** loops.
+    */
+    for(i=0; i<nOrderBy; i++){
+      if( MASKBIT(i) & obSat ) continue;
+      pOBExpr = sqlite3ExprSkipCollateAndLikely(pOrderBy->a[i].pExpr);
+      if( NEVER(pOBExpr==0) ) continue;
+      if( pOBExpr->op!=TK_COLUMN && pOBExpr->op!=TK_AGG_COLUMN ) continue;
+      if( pOBExpr->iTable!=iCur ) continue;
+      pTerm = sqlite3WhereFindTerm(&pWInfo->sWC, iCur, pOBExpr->iColumn,
+                       ~ready, eqOpMask, 0);
+      if( pTerm==0 ) continue;
+      if( pTerm->eOperator==WO_IN ){
+        /* IN terms are only valid for sorting in the ORDER BY LIMIT
+        ** optimization, and then only if they are actually used
+        ** by the query plan */
+        assert( wctrlFlags &
+               (WHERE_ORDERBY_LIMIT|WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX) );
+        for(j=0; j<pLoop->nLTerm && pTerm!=pLoop->aLTerm[j]; j++){}
+        if( j>=pLoop->nLTerm ) continue;
+      }
+      if( (pTerm->eOperator&(WO_EQ|WO_IS))!=0 && pOBExpr->iColumn>=0 ){
+        Parse *pParse = pWInfo->pParse;
+        CollSeq *pColl1 = sqlite3ExprNNCollSeq(pParse, pOrderBy->a[i].pExpr);
+        CollSeq *pColl2 = sqlite3ExprCompareCollSeq(pParse, pTerm->pExpr);
+        assert( pColl1 );
+        if( pColl2==0 || sqlite3StrICmp(pColl1->zName, pColl2->zName) ){
+          continue;
+        }
+        testcase( pTerm->pExpr->op==TK_IS );
+      }
+      obSat |= MASKBIT(i);
+    }
+
+    if( (pLoop->wsFlags & WHERE_ONEROW)==0 ){
+      if( pLoop->wsFlags & WHERE_IPK ){
+        if( pLoop->u.btree.pOrderBy
+         && OptimizationEnabled(db, SQLITE_OrderBySubq)
+         &&  wherePathMatchSubqueryOB(pWInfo,pLoop,iLoop,iCur,
+                                     pOrderBy,pRevMask, &obSat)
+        ){
+          nColumn = 0;
+          isOrderDistinct = 0;
+        }else{
+          nColumn = 1;
+        }
+        pIndex = 0;
+        nKeyCol = 0;
+      }else if( (pIndex = pLoop->u.btree.pIndex)==0 || pIndex->bUnordered ){
+        return 0;
+      }else{
+        nKeyCol = pIndex->nKeyCol;
+        nColumn = pIndex->nColumn;
+        assert( nColumn==nKeyCol+1 || !HasRowid(pIndex->pTable) );
+        assert( pIndex->aiColumn[nColumn-1]==XN_ROWID
+                          || !HasRowid(pIndex->pTable));
+        /* All relevant terms of the index must also be non-NULL in order
+        ** for isOrderDistinct to be true.  So the isOrderDistinct value
+        ** computed here might be a false positive.  Corrections will be
+        ** made at tag-20210426-1 below */
+        isOrderDistinct = IsUniqueIndex(pIndex)
+                          && (pLoop->wsFlags & WHERE_SKIPSCAN)==0;
+      }
+
+      /* Loop through all columns of the index and deal with the ones
+      ** that are not constrained by == or IN.
+      */
+      rev = revSet = 0;
+      distinctColumns = 0;
+      for(j=0; j<nColumn; j++){
+        u8 bOnce = 1; /* True to run the ORDER BY search loop */
+
+        assert( j>=pLoop->u.btree.nEq
+            || (pLoop->aLTerm[j]==0)==(j<pLoop->nSkip)
+        );
+        if( j<pLoop->u.btree.nEq && j>=pLoop->nSkip ){
+          u16 eOp = pLoop->aLTerm[j]->eOperator;
+
+          /* Skip over == and IS and ISNULL terms.  (Also skip IN terms when
+          ** doing WHERE_ORDERBY_LIMIT processing).  Except, IS and ISNULL
+          ** terms imply that the index is not UNIQUE NOT NULL in which case
+          ** the loop need to be marked as not order-distinct because it can
+          ** have repeated NULL rows.
+          **
+          ** If the current term is a column of an ((?,?) IN (SELECT...))
+          ** expression for which the SELECT returns more than one column,
+          ** check that it is the only column used by this loop. Otherwise,
+          ** if it is one of two or more, none of the columns can be
+          ** considered to match an ORDER BY term.
+          */
+          if( (eOp & eqOpMask)!=0 ){
+            if( eOp & (WO_ISNULL|WO_IS) ){
+              testcase( eOp & WO_ISNULL );
+              testcase( eOp & WO_IS );
+              testcase( isOrderDistinct );
+              isOrderDistinct = 0;
+            }
+            continue;
+          }else if( ALWAYS(eOp & WO_IN) ){
+            /* ALWAYS() justification: eOp is an equality operator due to the
+            ** j<pLoop->u.btree.nEq constraint above.  Any equality other
+            ** than WO_IN is captured by the previous "if".  So this one
+            ** always has to be WO_IN. */
+            Expr *pX = pLoop->aLTerm[j]->pExpr;
+            for(i=j+1; i<pLoop->u.btree.nEq; i++){
+              if( pLoop->aLTerm[i]->pExpr==pX ){
+                assert( (pLoop->aLTerm[i]->eOperator & WO_IN) );
+                bOnce = 0;
+                break;
+              }
+            }
+          }
+        }
+
+        /* Get the column number in the table (iColumn) and sort order
+        ** (revIdx) for the j-th column of the index.
+        */
+        if( pIndex ){
+          iColumn = pIndex->aiColumn[j];
+          revIdx = pIndex->aSortOrder[j] & KEYINFO_ORDER_DESC;
+          if( iColumn==pIndex->pTable->iPKey ) iColumn = XN_ROWID;
+        }else{
+          iColumn = XN_ROWID;
+          revIdx = 0;
+        }
+
+        /* An unconstrained column that might be NULL means that this
+        ** WhereLoop is not well-ordered.  tag-20210426-1
+        */
+        if( isOrderDistinct ){
+          if( iColumn>=0
+           && j>=pLoop->u.btree.nEq
+           && pIndex->pTable->aCol[iColumn].notNull==0
+          ){
+            isOrderDistinct = 0;
+          }
+          if( iColumn==XN_EXPR ){
+            isOrderDistinct = 0;
+          }
+        }
+
+        /* Find the ORDER BY term that corresponds to the j-th column
+        ** of the index and mark that ORDER BY term having been satisfied.
+        */
+        isMatch = 0;
+        for(i=0; bOnce && i<nOrderBy; i++){
+          if( MASKBIT(i) & obSat ) continue;
+          pOBExpr = sqlite3ExprSkipCollateAndLikely(pOrderBy->a[i].pExpr);
+          testcase( wctrlFlags & WHERE_GROUPBY );
+          testcase( wctrlFlags & WHERE_DISTINCTBY );
+          if( NEVER(pOBExpr==0) ) continue;
+          if( (wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY))==0 ) bOnce = 0;
+          if( iColumn>=XN_ROWID ){
+            if( pOBExpr->op!=TK_COLUMN && pOBExpr->op!=TK_AGG_COLUMN ) continue;
+            if( pOBExpr->iTable!=iCur ) continue;
+            if( pOBExpr->iColumn!=iColumn ) continue;
+          }else{
+            Expr *pIxExpr = pIndex->aColExpr->a[j].pExpr;
+            if( sqlite3ExprCompareSkip(pOBExpr, pIxExpr, iCur) ){
+              continue;
+            }
+          }
+          if( iColumn!=XN_ROWID ){
+            pColl = sqlite3ExprNNCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
+            if( sqlite3StrICmp(pColl->zName, pIndex->azColl[j])!=0 ) continue;
+          }
+          if( wctrlFlags & WHERE_DISTINCTBY ){
+            pLoop->u.btree.nDistinctCol = j+1;
+          }
+          isMatch = 1;
+          break;
+        }
+        if( isMatch && (wctrlFlags & WHERE_GROUPBY)==0 ){
+          /* Make sure the sort order is compatible in an ORDER BY clause.
+          ** Sort order is irrelevant for a GROUP BY clause. */
+          if( revSet ){
+            if( (rev ^ revIdx)
+                           != (pOrderBy->a[i].fg.sortFlags&KEYINFO_ORDER_DESC)
+            ){
+              isMatch = 0;
+            }
+          }else{
+            rev = revIdx ^ (pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_DESC);
+            if( rev ) *pRevMask |= MASKBIT(iLoop);
+            revSet = 1;
+          }
+        }
+        if( isMatch && (pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_BIGNULL) ){
+          if( j==pLoop->u.btree.nEq ){
+            pLoop->wsFlags |= WHERE_BIGNULL_SORT;
+          }else{
+            isMatch = 0;
+          }
+        }
+        if( isMatch ){
+          if( iColumn==XN_ROWID ){
+            testcase( distinctColumns==0 );
+            distinctColumns = 1;
+          }
+          obSat |= MASKBIT(i);
+        }else{
+          /* No match found */
+          if( j==0 || j<nKeyCol ){
+            testcase( isOrderDistinct!=0 );
+            isOrderDistinct = 0;
+          }
+          break;
+        }
+      } /* end Loop over all index columns */
+      if( distinctColumns ){
+        testcase( isOrderDistinct==0 );
+        isOrderDistinct = 1;
+      }
+    } /* end-if not one-row */
+
+    /* Mark off any other ORDER BY terms that reference pLoop */
+    if( isOrderDistinct ){
+      orderDistinctMask |= pLoop->maskSelf;
+      for(i=0; i<nOrderBy; i++){
+        Expr *p;
+        Bitmask mTerm;
+        if( MASKBIT(i) & obSat ) continue;
+        p = pOrderBy->a[i].pExpr;
+        mTerm = sqlite3WhereExprUsage(&pWInfo->sMaskSet,p);
+        if( mTerm==0 && !sqlite3ExprIsConstant(0,p) ) continue;
+        if( (mTerm&~orderDistinctMask)==0 ){
+          obSat |= MASKBIT(i);
+        }
+      }
+    }
+  } /* End the loop over all WhereLoops from outer-most down to inner-most */
+  if( obSat==obDone ) return (i8)nOrderBy;
+  if( !isOrderDistinct ){
+    for(i=nOrderBy-1; i>0; i--){
+      Bitmask m = ALWAYS(i<BMS) ? MASKBIT(i) - 1 : 0;
+      if( (obSat&m)==m ) return i;
+    }
+    return 0;
+  }
+  return -1;
+}
+
+
+/*
+** If the WHERE_GROUPBY flag is set in the mask passed to sqlite3WhereBegin(),
+** the planner assumes that the specified pOrderBy list is actually a GROUP
+** BY clause - and so any order that groups rows as required satisfies the
+** request.
+**
+** Normally, in this case it is not possible for the caller to determine
+** whether or not the rows are really being delivered in sorted order, or
+** just in some other order that provides the required grouping. However,
+** if the WHERE_SORTBYGROUP flag is also passed to sqlite3WhereBegin(), then
+** this function may be called on the returned WhereInfo object. It returns
+** true if the rows really will be sorted in the specified order, or false
+** otherwise.
+**
+** For example, assuming:
+**
+**   CREATE INDEX i1 ON t1(x, Y);
+**
+** then
+**
+**   SELECT * FROM t1 GROUP BY x,y ORDER BY x,y;   -- IsSorted()==1
+**   SELECT * FROM t1 GROUP BY y,x ORDER BY y,x;   -- IsSorted()==0
+*/
+SQLITE_PRIVATE int sqlite3WhereIsSorted(WhereInfo *pWInfo){
+  assert( pWInfo->wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY) );
+  assert( pWInfo->wctrlFlags & WHERE_SORTBYGROUP );
+  return pWInfo->sorted;
+}
+
+#ifdef WHERETRACE_ENABLED
+/* For debugging use only: */
+static const char *wherePathName(WherePath *pPath, int nLoop, WhereLoop *pLast){
+  static char zName[65];
+  int i;
+  for(i=0; i<nLoop; i++){ zName[i] = pPath->aLoop[i]->cId; }
+  if( pLast ) zName[i++] = pLast->cId;
+  zName[i] = 0;
+  return zName;
+}
+#endif
+
+/*
+** Return the cost of sorting nRow rows, assuming that the keys have
+** nOrderby columns and that the first nSorted columns are already in
+** order.
+*/
+static LogEst whereSortingCost(
+  WhereInfo *pWInfo, /* Query planning context */
+  LogEst nRow,       /* Estimated number of rows to sort */
+  int nOrderBy,      /* Number of ORDER BY clause terms */
+  int nSorted        /* Number of initial ORDER BY terms naturally in order */
+){
+  /* Estimated cost of a full external sort, where N is
+  ** the number of rows to sort is:
+  **
+  **   cost = (K * N * log(N)).
+  **
+  ** Or, if the order-by clause has X terms but only the last Y
+  ** terms are out of order, then block-sorting will reduce the
+  ** sorting cost to:
+  **
+  **   cost = (K * N * log(N)) * (Y/X)
+  **
+  ** The constant K is at least 2.0 but will be larger if there are a
+  ** large number of columns to be sorted, as the sorting time is
+  ** proportional to the amount of content to be sorted.  The algorithm
+  ** does not currently distinguish between fat columns (BLOBs and TEXTs)
+  ** and skinny columns (INTs).  It just uses the number of columns as
+  ** an approximation for the row width.
+  **
+  ** And extra factor of 2.0 or 3.0 is added to the sorting cost if the sort
+  ** is built using OP_IdxInsert and OP_Sort rather than with OP_SorterInsert.
+  */
+  LogEst rSortCost, nCol;
+  assert( pWInfo->pSelect!=0 );
+  assert( pWInfo->pSelect->pEList!=0 );
+  /* TUNING: sorting cost proportional to the number of output columns: */
+  nCol = sqlite3LogEst((pWInfo->pSelect->pEList->nExpr+59)/30);
+  rSortCost = nRow + nCol;
+  if( nSorted>0 ){
+    /* Scale the result by (Y/X) */
+    rSortCost += sqlite3LogEst((nOrderBy-nSorted)*100/nOrderBy) - 66;
+  }
+
+  /* Multiple by log(M) where M is the number of output rows.
+  ** Use the LIMIT for M if it is smaller.  Or if this sort is for
+  ** a DISTINCT operator, M will be the number of distinct output
+  ** rows, so fudge it downwards a bit.
+  */
+  if( (pWInfo->wctrlFlags & WHERE_USE_LIMIT)!=0 ){
+    rSortCost += 10;       /* TUNING: Extra 2.0x if using LIMIT */
+    if( nSorted!=0 ){
+      rSortCost += 6;      /* TUNING: Extra 1.5x if also using partial sort */
+    }
+    if( pWInfo->iLimit<nRow ){
+      nRow = pWInfo->iLimit;
+    }
+  }else if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT) ){
+    /* TUNING: In the sort for a DISTINCT operator, assume that the DISTINCT
+    ** reduces the number of output rows by a factor of 2 */
+    if( nRow>10 ){ nRow -= 10;  assert( 10==sqlite3LogEst(2) ); }
+  }
+  rSortCost += estLog(nRow);
+  return rSortCost;
+}
+
+/*
+** Compute the maximum number of paths in the solver algorithm, for
+** queries that have three or more terms in the FROM clause.  Queries with
+** two or fewer FROM clause terms are handled by the caller.
+**
+** Query planning is NP-hard.  We must limit the number of paths at
+** each step of the solver search algorithm to avoid exponential behavior.
+**
+** The value returned is a tuning parameter.  Currently the value is:
+**
+**     18    for star queries
+**     12    otherwise
+**
+** For the purposes of this heuristic, a star-query is defined as a query
+** with a large central table that is joined using an INNER JOIN,
+** not CROSS or OUTER JOINs, against four or more smaller tables.
+** The central table is called the "fact" table.  The smaller tables
+** that get joined are "dimension tables".  Also, any table that is
+** self-joined cannot be a dimension table; we assume that dimension
+** tables may only be joined against fact tables.
+**
+** SIDE EFFECT:  (and really the whole point of this subroutine)
+**
+** If pWInfo describes a star-query, then the cost for SCANs of dimension
+** WhereLoops is increased to be slightly larger than the cost of a SCAN
+** in the fact table.  Only SCAN costs are increased.  SEARCH costs are
+** unchanged. This heuristic helps keep fact tables in outer loops. Without
+** this heuristic, paths with fact tables in outer loops tend to get pruned
+** by the mxChoice limit on the number of paths, resulting in poor query
+** plans.  See the starschema1.test test module for examples of queries
+** that need this heuristic to find good query plans.
+**
+** This heuristic can be completely disabled, so that no query is
+** considered a star-query, using SQLITE_TESTCTRL_OPTIMIZATION to
+** disable the SQLITE_StarQuery optimization.  In the CLI, the command
+** to do that is:  ".testctrl opt -starquery".
+**
+** HISTORICAL NOTES:
+**
+** This optimization was first added on 2024-05-09 by check-in 38db9b5c83d.
+** The original optimization reduced the cost and output size estimate for
+** fact tables to help them move to outer loops.  But months later (as people
+** started upgrading) performance regression reports started caming in,
+** including:
+**
+**    forum post b18ef983e68d06d1 (2024-12-21)
+**    forum post 0025389d0860af82 (2025-01-14)
+**    forum post d87570a145599033 (2025-01-17)
+**
+** To address these, the criteria for a star-query was tightened to exclude
+** cases where the fact and dimensions are separated by an outer join, and
+** the affect of star-schema detection was changed to increase the rRun cost
+** on just full table scans of dimension tables, rather than reducing costs
+** in the all access methods of the fact table.
+*/
+static int computeMxChoice(WhereInfo *pWInfo){
+  int nLoop = pWInfo->nLevel;    /* Number of terms in the join */
+  WhereLoop *pWLoop;             /* For looping over WhereLoops */
+
+#ifdef SQLITE_DEBUG
+  /* The star-query detection code below makes use of the following
+  ** properties of the WhereLoop list, so verify them before
+  ** continuing:
+  **    (1)  .maskSelf is the bitmask corresponding to .iTab
+  **    (2)  The WhereLoop list is in ascending .iTab order
+  */
+  for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
+    assert( pWLoop->maskSelf==MASKBIT(pWLoop->iTab) );
+    assert( pWLoop->pNextLoop==0 || pWLoop->iTab<=pWLoop->pNextLoop->iTab );
+  }
+#endif /* SQLITE_DEBUG */
+
+  if( nLoop>=5
+   && !pWInfo->bStarDone
+   && OptimizationEnabled(pWInfo->pParse->db, SQLITE_StarQuery)
+  ){
+    SrcItem *aFromTabs;    /* All terms of the FROM clause */
+    int iFromIdx;          /* Term of FROM clause is the candidate fact-table */
+    Bitmask m;             /* Bitmask for candidate fact-table */
+    Bitmask mSelfJoin = 0; /* Tables that cannot be dimension tables */
+    WhereLoop *pStart;     /* Where to start searching for dimension-tables */
+
+    pWInfo->bStarDone = 1; /* Only do this computation once */
+
+    /* Look for fact tables with four or more dimensions where the
+    ** dimension tables are not separately from the fact tables by an outer
+    ** or cross join.  Adjust cost weights if found.
+    */
+    assert( !pWInfo->bStarUsed );
+    aFromTabs = pWInfo->pTabList->a;
+    pStart = pWInfo->pLoops;
+    for(iFromIdx=0, m=1; iFromIdx<nLoop; iFromIdx++, m<<=1){
+      int nDep = 0;             /* Number of dimension tables */
+      LogEst mxRun;             /* Maximum SCAN cost of a fact table */
+      Bitmask mSeen = 0;        /* Mask of dimension tables */
+      SrcItem *pFactTab;        /* The candidate fact table */
+
+      pFactTab = aFromTabs + iFromIdx;
+      if( (pFactTab->fg.jointype & (JT_OUTER|JT_CROSS))!=0 ){
+        /* If the candidate fact-table is the right table of an outer join
+        ** restrict the search for dimension-tables to be tables to the right
+        ** of the fact-table. */
+        if( iFromIdx+4 > nLoop ) break;  /* Impossible to reach nDep>=4 */
+        while( pStart && pStart->iTab<=iFromIdx ){
+          pStart = pStart->pNextLoop;
+        }
+      }
+      for(pWLoop=pStart; pWLoop; pWLoop=pWLoop->pNextLoop){
+        if( (aFromTabs[pWLoop->iTab].fg.jointype & (JT_OUTER|JT_CROSS))!=0 ){
+          /* Fact-tables and dimension-tables cannot be separated by an
+          ** outer join (at least for the definition of fact- and dimension-
+          ** used by this heuristic). */
+          break;
+        }
+        if( (pWLoop->prereq & m)!=0        /* pWInfo depends on iFromIdx */
+         && (pWLoop->maskSelf & mSeen)==0  /* pWInfo not already a dependency */
+         && (pWLoop->maskSelf & mSelfJoin)==0 /* Not a self-join */
+        ){
+          if( aFromTabs[pWLoop->iTab].pSTab==pFactTab->pSTab ){
+            mSelfJoin |= m;
+          }else{
+            nDep++;
+            mSeen |= pWLoop->maskSelf;
+          }
+        }
+      }
+      if( nDep<=3 ) continue;
+
+      /* If we reach this point, it means that pFactTab is a fact table
+      ** with four or more dimensions connected by inner joins.  Proceed
+      ** to make cost adjustments. */
+
+#ifdef WHERETRACE_ENABLED
+      /* Make sure rStarDelta values are initialized */
+      if( !pWInfo->bStarUsed ){
+        for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
+          pWLoop->rStarDelta = 0;
+        }
+      }
+#endif
+      pWInfo->bStarUsed = 1;
+
+      /* Compute the maximum cost of any WhereLoop for the
+      ** fact table plus one epsilon */
+      mxRun = LOGEST_MIN;
+      for(pWLoop=pStart; pWLoop; pWLoop=pWLoop->pNextLoop){
+        if( pWLoop->iTab<iFromIdx ) continue;
+        if( pWLoop->iTab>iFromIdx ) break;
+        if( pWLoop->rRun>mxRun ) mxRun = pWLoop->rRun;
+      }
+      if( ALWAYS(mxRun<LOGEST_MAX) ) mxRun++;
+
+      /* Increase the cost of table scans for dimension tables to be
+      ** slightly more than the maximum cost of the fact table */
+      for(pWLoop=pStart; pWLoop; pWLoop=pWLoop->pNextLoop){
+        if( (pWLoop->maskSelf & mSeen)==0 ) continue;
+        if( pWLoop->nLTerm ) continue;
+        if( pWLoop->rRun<mxRun ){
+#ifdef WHERETRACE_ENABLED /* 0x80000 */
+          if( sqlite3WhereTrace & 0x80000 ){
+            SrcItem *pDim = aFromTabs + pWLoop->iTab;
+            sqlite3DebugPrintf(
+              "Increase SCAN cost of dimension %s(%d) of fact %s(%d) to %d\n",
+              pDim->zAlias ? pDim->zAlias: pDim->pSTab->zName, pWLoop->iTab,
+              pFactTab->zAlias ? pFactTab->zAlias : pFactTab->pSTab->zName,
+              iFromIdx, mxRun
+            );
+          }
+          pWLoop->rStarDelta = mxRun - pWLoop->rRun;
+#endif /* WHERETRACE_ENABLED */
+          pWLoop->rRun = mxRun;
+        }
+      }
+    }
+#ifdef WHERETRACE_ENABLED /* 0x80000 */
+    if( (sqlite3WhereTrace & 0x80000)!=0 && pWInfo->bStarUsed ){
+      sqlite3DebugPrintf("WhereLoops changed by star-query heuristic:\n");
+      for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
+        if( pWLoop->rStarDelta ){
+          sqlite3WhereLoopPrint(pWLoop, &pWInfo->sWC);
+        }
+      }
+    }
+#endif
+  }
+  return pWInfo->bStarUsed ? 18 : 12;
+}
+
+/*
+** Two WhereLoop objects, pCandidate and pBaseline, are known to have the
+** same cost.  Look deep into each to see if pCandidate is even slightly
+** better than pBaseline.  Return false if it is, if pCandidate is is preferred.
+** Return true if pBaseline is preferred or if we cannot tell the difference.
+**
+**    Result       Meaning
+**    --------     ----------------------------------------------------------
+**    true         We cannot tell the difference in pCandidate and pBaseline
+**    false        pCandidate seems like a better choice than pBaseline
+*/
+static SQLITE_NOINLINE int whereLoopIsNoBetter(
+  const WhereLoop *pCandidate,
+  const WhereLoop *pBaseline
+){
+  if( (pCandidate->wsFlags & WHERE_INDEXED)==0 ) return 1;
+  if( (pBaseline->wsFlags & WHERE_INDEXED)==0 ) return 1;
+  if( pCandidate->u.btree.pIndex->szIdxRow <
+        pBaseline->u.btree.pIndex->szIdxRow ) return 0;
+  return 1;
+}
+
+/*
+** Given the list of WhereLoop objects at pWInfo->pLoops, this routine
+** attempts to find the lowest cost path that visits each WhereLoop
+** once.  This path is then loaded into the pWInfo->a[].pWLoop fields.
+**
+** Assume that the total number of output rows that will need to be sorted
+** will be nRowEst (in the 10*log2 representation).  Or, ignore sorting
+** costs if nRowEst==0.
+**
+** Return SQLITE_OK on success or SQLITE_NOMEM of a memory allocation
+** error occurs.
+*/
+static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
+  int mxChoice;             /* Maximum number of simultaneous paths tracked */
+  int nLoop;                /* Number of terms in the join */
+  Parse *pParse;            /* Parsing context */
+  int iLoop;                /* Loop counter over the terms of the join */
+  int ii, jj;               /* Loop counters */
+  int mxI = 0;              /* Index of next entry to replace */
+  int nOrderBy;             /* Number of ORDER BY clause terms */
+  LogEst mxCost = 0;        /* Maximum cost of a set of paths */
+  LogEst mxUnsort = 0;      /* Maximum unsorted cost of a set of path */
+  int nTo, nFrom;           /* Number of valid entries in aTo[] and aFrom[] */
+  WherePath *aFrom;         /* All nFrom paths at the previous level */
+  WherePath *aTo;           /* The nTo best paths at the current level */
+  WherePath *pFrom;         /* An element of aFrom[] that we are working on */
+  WherePath *pTo;           /* An element of aTo[] that we are working on */
+  WhereLoop *pWLoop;        /* One of the WhereLoop objects */
+  WhereLoop **pX;           /* Used to divy up the pSpace memory */
+  LogEst *aSortCost = 0;    /* Sorting and partial sorting costs */
+  char *pSpace;             /* Temporary memory used by this routine */
+  int nSpace;               /* Bytes of space allocated at pSpace */
+
+  pParse = pWInfo->pParse;
+  nLoop = pWInfo->nLevel;
+  WHERETRACE(0x002, ("---- begin solver.  (nRowEst=%d, nQueryLoop=%d)\n",
+                     nRowEst, pParse->nQueryLoop));
+  /* TUNING: mxChoice is the maximum number of possible paths to preserve
+  ** at each step.  Based on the number of loops in the FROM clause:
+  **
+  **     nLoop      mxChoice
+  **     -----      --------
+  **       1            1            // the most common case
+  **       2            5
+  **       3+        12 or 18        // see computeMxChoice()
+  */
+  if( nLoop<=1 ){
+    mxChoice = 1;
+  }else if( nLoop==2 ){
+    mxChoice = 5;
+  }else if( pParse->nErr ){
+    mxChoice = 1;
+  }else{
+    mxChoice = computeMxChoice(pWInfo);
+  }
+  assert( nLoop<=pWInfo->pTabList->nSrc );
+
+  /* If nRowEst is zero and there is an ORDER BY clause, ignore it. In this
+  ** case the purpose of this call is to estimate the number of rows returned
+  ** by the overall query. Once this estimate has been obtained, the caller
+  ** will invoke this function a second time, passing the estimate as the
+  ** nRowEst parameter.  */
+  if( pWInfo->pOrderBy==0 || nRowEst==0 ){
+    nOrderBy = 0;
+  }else{
+    nOrderBy = pWInfo->pOrderBy->nExpr;
+  }
+
+  /* Allocate and initialize space for aTo, aFrom and aSortCost[] */
+  nSpace = (sizeof(WherePath)+sizeof(WhereLoop*)*nLoop)*mxChoice*2;
+  nSpace += sizeof(LogEst) * nOrderBy;
+  pSpace = sqlite3StackAllocRawNN(pParse->db, nSpace);
+  if( pSpace==0 ) return SQLITE_NOMEM_BKPT;
+  aTo = (WherePath*)pSpace;
+  aFrom = aTo+mxChoice;
+  memset(aFrom, 0, sizeof(aFrom[0]));
+  pX = (WhereLoop**)(aFrom+mxChoice);
+  for(ii=mxChoice*2, pFrom=aTo; ii>0; ii--, pFrom++, pX += nLoop){
+    pFrom->aLoop = pX;
+  }
+  if( nOrderBy ){
+    /* If there is an ORDER BY clause and it is not being ignored, set up
+    ** space for the aSortCost[] array. Each element of the aSortCost array
+    ** is either zero - meaning it has not yet been initialized - or the
+    ** cost of sorting nRowEst rows of data where the first X terms of
+    ** the ORDER BY clause are already in order, where X is the array
+    ** index.  */
+    aSortCost = (LogEst*)pX;
+    memset(aSortCost, 0, sizeof(LogEst) * nOrderBy);
+  }
+  assert( aSortCost==0 || &pSpace[nSpace]==(char*)&aSortCost[nOrderBy] );
+  assert( aSortCost!=0 || &pSpace[nSpace]==(char*)pX );
+
+  /* Seed the search with a single WherePath containing zero WhereLoops.
+  **
+  ** TUNING: Do not let the number of iterations go above 28.  If the cost
+  ** of computing an automatic index is not paid back within the first 28
+  ** rows, then do not use the automatic index. */
+  aFrom[0].nRow = MIN(pParse->nQueryLoop, 48);  assert( 48==sqlite3LogEst(28) );
+  nFrom = 1;
+  assert( aFrom[0].isOrdered==0 );
+  if( nOrderBy ){
+    /* If nLoop is zero, then there are no FROM terms in the query. Since
+    ** in this case the query may return a maximum of one row, the results
+    ** are already in the requested order. Set isOrdered to nOrderBy to
+    ** indicate this. Or, if nLoop is greater than zero, set isOrdered to
+    ** -1, indicating that the result set may or may not be ordered,
+    ** depending on the loops added to the current plan.  */
+    aFrom[0].isOrdered = nLoop>0 ? -1 : nOrderBy;
+  }
+
+  /* Compute successively longer WherePaths using the previous generation
+  ** of WherePaths as the basis for the next.  Keep track of the mxChoice
+  ** best paths at each generation */
+  for(iLoop=0; iLoop<nLoop; iLoop++){
+    nTo = 0;
+    for(ii=0, pFrom=aFrom; ii<nFrom; ii++, pFrom++){
+      for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
+        LogEst nOut;                      /* Rows visited by (pFrom+pWLoop) */
+        LogEst rCost;                     /* Cost of path (pFrom+pWLoop) */
+        LogEst rUnsort;                   /* Unsorted cost of (pFrom+pWLoop) */
+        i8 isOrdered;                     /* isOrdered for (pFrom+pWLoop) */
+        Bitmask maskNew;                  /* Mask of src visited by (..) */
+        Bitmask revMask;                  /* Mask of rev-order loops for (..) */
+
+        if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
+        if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
+        if( (pWLoop->wsFlags & WHERE_AUTO_INDEX)!=0 && pFrom->nRow<3 ){
+          /* Do not use an automatic index if the this loop is expected
+          ** to run less than 1.25 times.  It is tempting to also exclude
+          ** automatic index usage on an outer loop, but sometimes an automatic
+          ** index is useful in the outer loop of a correlated subquery. */
+          assert( 10==sqlite3LogEst(2) );
+          continue;
+        }
+
+        /* At this point, pWLoop is a candidate to be the next loop.
+        ** Compute its cost */
+        rUnsort = pWLoop->rRun + pFrom->nRow;
+        if( pWLoop->rSetup ){
+          rUnsort = sqlite3LogEstAdd(pWLoop->rSetup, rUnsort);
+        }
+        rUnsort = sqlite3LogEstAdd(rUnsort, pFrom->rUnsort);
+        nOut = pFrom->nRow + pWLoop->nOut;
+        maskNew = pFrom->maskLoop | pWLoop->maskSelf;
+        isOrdered = pFrom->isOrdered;
+        if( isOrdered<0 ){
+          revMask = 0;
+          isOrdered = wherePathSatisfiesOrderBy(pWInfo,
+                       pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags,
+                       iLoop, pWLoop, &revMask);
+        }else{
+          revMask = pFrom->revLoop;
+        }
+        if( isOrdered>=0 && isOrdered<nOrderBy ){
+          if( aSortCost[isOrdered]==0 ){
+            aSortCost[isOrdered] = whereSortingCost(
+                pWInfo, nRowEst, nOrderBy, isOrdered
+            );
+          }
+          /* TUNING:  Add a small extra penalty (3) to sorting as an
+          ** extra encouragement to the query planner to select a plan
+          ** where the rows emerge in the correct order without any sorting
+          ** required. */
+          rCost = sqlite3LogEstAdd(rUnsort, aSortCost[isOrdered]) + 3;
+
+          WHERETRACE(0x002,
+              ("---- sort cost=%-3d (%d/%d) increases cost %3d to %-3d\n",
+               aSortCost[isOrdered], (nOrderBy-isOrdered), nOrderBy,
+               rUnsort, rCost));
+        }else{
+          rCost = rUnsort;
+          rUnsort -= 2;  /* TUNING:  Slight bias in favor of no-sort plans */
+        }
+
+        /* Check to see if pWLoop should be added to the set of
+        ** mxChoice best-so-far paths.
+        **
+        ** First look for an existing path among best-so-far paths
+        ** that covers the same set of loops and has the same isOrdered
+        ** setting as the current path candidate.
+        **
+        ** The term "((pTo->isOrdered^isOrdered)&0x80)==0" is equivalent
+        ** to (pTo->isOrdered==(-1))==(isOrdered==(-1))" for the range
+        ** of legal values for isOrdered, -1..64.
+        */
+        testcase( nTo==0 );
+        for(jj=0, pTo=aTo; jj<nTo; jj++, pTo++){
+          if( pTo->maskLoop==maskNew
+           && ((pTo->isOrdered^isOrdered)&0x80)==0
+          ){
+            testcase( jj==nTo-1 );
+            break;
+          }
+        }
+        if( jj>=nTo ){
+          /* None of the existing best-so-far paths match the candidate. */
+          if( nTo>=mxChoice
+           && (rCost>mxCost || (rCost==mxCost && rUnsort>=mxUnsort))
+          ){
+            /* The current candidate is no better than any of the mxChoice
+            ** paths currently in the best-so-far buffer.  So discard
+            ** this candidate as not viable. */
+#ifdef WHERETRACE_ENABLED /* 0x4 */
+            if( sqlite3WhereTrace&0x4 ){
+              sqlite3DebugPrintf("Skip   %s cost=%-3d,%3d,%3d order=%c\n",
+                  wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsort,
+                  isOrdered>=0 ? isOrdered+'0' : '?');
+            }
+#endif
+            continue;
+          }
+          /* If we reach this points it means that the new candidate path
+          ** needs to be added to the set of best-so-far paths. */
+          if( nTo<mxChoice ){
+            /* Increase the size of the aTo set by one */
+            jj = nTo++;
+          }else{
+            /* New path replaces the prior worst to keep count below mxChoice */
+            jj = mxI;
+          }
+          pTo = &aTo[jj];
+#ifdef WHERETRACE_ENABLED /* 0x4 */
+          if( sqlite3WhereTrace&0x4 ){
+            sqlite3DebugPrintf("New    %s cost=%-3d,%3d,%3d order=%c\n",
+                wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsort,
+                isOrdered>=0 ? isOrdered+'0' : '?');
+          }
+#endif
+        }else{
+          /* Control reaches here if best-so-far path pTo=aTo[jj] covers the
+          ** same set of loops and has the same isOrdered setting as the
+          ** candidate path.  Check to see if the candidate should replace
+          ** pTo or if the candidate should be skipped.
+          **
+          ** The conditional is an expanded vector comparison equivalent to:
+          **   (pTo->rCost,pTo->nRow,pTo->rUnsort) <= (rCost,nOut,rUnsort)
+          */
+          if( (pTo->rCost<rCost)
+           || (pTo->rCost==rCost && pTo->nRow<nOut)
+           || (pTo->rCost==rCost && pTo->nRow==nOut && pTo->rUnsort<rUnsort)
+           || (pTo->rCost==rCost && pTo->nRow==nOut && pTo->rUnsort==rUnsort
+                  && whereLoopIsNoBetter(pWLoop, pTo->aLoop[iLoop]) )
+          ){
+#ifdef WHERETRACE_ENABLED /* 0x4 */
+            if( sqlite3WhereTrace&0x4 ){
+              sqlite3DebugPrintf(
+                  "Skip   %s cost=%-3d,%3d,%3d order=%c",
+                  wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsort,
+                  isOrdered>=0 ? isOrdered+'0' : '?');
+              sqlite3DebugPrintf("   vs %s cost=%-3d,%3d,%3d order=%c\n",
+                  wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
+                  pTo->rUnsort, pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
+            }
+#endif
+            /* Discard the candidate path from further consideration */
+            testcase( pTo->rCost==rCost );
+            continue;
+          }
+          testcase( pTo->rCost==rCost+1 );
+          /* Control reaches here if the candidate path is better than the
+          ** pTo path.  Replace pTo with the candidate. */
+#ifdef WHERETRACE_ENABLED /* 0x4 */
+          if( sqlite3WhereTrace&0x4 ){
+            sqlite3DebugPrintf(
+                "Update %s cost=%-3d,%3d,%3d order=%c",
+                wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsort,
+                isOrdered>=0 ? isOrdered+'0' : '?');
+            sqlite3DebugPrintf("  was %s cost=%-3d,%3d,%3d order=%c\n",
+                wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
+                pTo->rUnsort, pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
+          }
+#endif
+        }
+        /* pWLoop is a winner.  Add it to the set of best so far */
+        pTo->maskLoop = pFrom->maskLoop | pWLoop->maskSelf;
+        pTo->revLoop = revMask;
+        pTo->nRow = nOut;
+        pTo->rCost = rCost;
+        pTo->rUnsort = rUnsort;
+        pTo->isOrdered = isOrdered;
+        memcpy(pTo->aLoop, pFrom->aLoop, sizeof(WhereLoop*)*iLoop);
+        pTo->aLoop[iLoop] = pWLoop;
+        if( nTo>=mxChoice ){
+          mxI = 0;
+          mxCost = aTo[0].rCost;
+          mxUnsort = aTo[0].nRow;
+          for(jj=1, pTo=&aTo[1]; jj<mxChoice; jj++, pTo++){
+            if( pTo->rCost>mxCost
+             || (pTo->rCost==mxCost && pTo->rUnsort>mxUnsort)
+            ){
+              mxCost = pTo->rCost;
+              mxUnsort = pTo->rUnsort;
+              mxI = jj;
+            }
+          }
+        }
+      }
+    }
+
+#ifdef WHERETRACE_ENABLED  /* >=2 */
+    if( sqlite3WhereTrace & 0x02 ){
+      LogEst rMin, rFloor = 0;
+      int nDone = 0;
+      int nProgress;
+      sqlite3DebugPrintf("---- after round %d ----\n", iLoop);
+      do{
+        nProgress = 0;
+        rMin = 0x7fff;
+        for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
+          if( pTo->rCost>rFloor && pTo->rCost<rMin ) rMin = pTo->rCost;
+        }
+        for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
+          if( pTo->rCost==rMin ){
+            sqlite3DebugPrintf(" %s cost=%-3d nrow=%-3d order=%c",
+               wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
+               pTo->isOrdered>=0 ? (pTo->isOrdered+'0') : '?');
+            if( pTo->isOrdered>0 ){
+              sqlite3DebugPrintf(" rev=0x%llx\n", pTo->revLoop);
+            }else{
+              sqlite3DebugPrintf("\n");
+            }
+            nDone++;
+            nProgress++;
+          }
+        }
+        rFloor = rMin;
+      }while( nDone<nTo && nProgress>0 );
+    }
+#endif
+
+    /* Swap the roles of aFrom and aTo for the next generation */
+    pFrom = aTo;
+    aTo = aFrom;
+    aFrom = pFrom;
+    nFrom = nTo;
+  }
+
+  if( nFrom==0 ){
+    sqlite3ErrorMsg(pParse, "no query solution");
+    sqlite3StackFreeNN(pParse->db, pSpace);
+    return SQLITE_ERROR;
+  }
+
+  /* Find the lowest cost path.  pFrom will be left pointing to that path */
+  pFrom = aFrom;
+  for(ii=1; ii<nFrom; ii++){
+    if( pFrom->rCost>aFrom[ii].rCost ) pFrom = &aFrom[ii];
+  }
+  assert( pWInfo->nLevel==nLoop );
+  /* Load the lowest cost path into pWInfo */
+  for(iLoop=0; iLoop<nLoop; iLoop++){
+    WhereLevel *pLevel = pWInfo->a + iLoop;
+    pLevel->pWLoop = pWLoop = pFrom->aLoop[iLoop];
+    pLevel->iFrom = pWLoop->iTab;
+    pLevel->iTabCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor;
+  }
+  if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0
+   && (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0
+   && pWInfo->eDistinct==WHERE_DISTINCT_NOOP
+   && nRowEst
+  ){
+    Bitmask notUsed;
+    int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pResultSet, pFrom,
+                 WHERE_DISTINCTBY, nLoop-1, pFrom->aLoop[nLoop-1], ¬Used);
+    if( rc==pWInfo->pResultSet->nExpr ){
+      pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
+    }
+  }
+  pWInfo->bOrderedInnerLoop = 0;
+  if( pWInfo->pOrderBy ){
+    pWInfo->nOBSat = pFrom->isOrdered;
+    if( pWInfo->wctrlFlags & WHERE_DISTINCTBY ){
+      if( pFrom->isOrdered==pWInfo->pOrderBy->nExpr ){
+        pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
+      }
+      /* vvv--- See check-in [12ad822d9b827777] on 2023-03-16 ---vvv */
+      assert( pWInfo->pSelect->pOrderBy==0
+           || pWInfo->nOBSat <= pWInfo->pSelect->pOrderBy->nExpr );
+    }else{
+      pWInfo->revMask = pFrom->revLoop;
+      if( pWInfo->nOBSat<=0 ){
+        pWInfo->nOBSat = 0;
+        if( nLoop>0 ){
+          u32 wsFlags = pFrom->aLoop[nLoop-1]->wsFlags;
+          if( (wsFlags & WHERE_ONEROW)==0
+           && (wsFlags&(WHERE_IPK|WHERE_COLUMN_IN))!=(WHERE_IPK|WHERE_COLUMN_IN)
+          ){
+            Bitmask m = 0;
+            int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, pFrom,
+                      WHERE_ORDERBY_LIMIT, nLoop-1, pFrom->aLoop[nLoop-1], &m);
+            testcase( wsFlags & WHERE_IPK );
+            testcase( wsFlags & WHERE_COLUMN_IN );
+            if( rc==pWInfo->pOrderBy->nExpr ){
+              pWInfo->bOrderedInnerLoop = 1;
+              pWInfo->revMask = m;
+            }
+          }
+        }
+      }else if( nLoop
+            && pWInfo->nOBSat==1
+            && (pWInfo->wctrlFlags & (WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX))!=0
+            ){
+        pWInfo->bOrderedInnerLoop = 1;
+      }
+    }
+    if( (pWInfo->wctrlFlags & WHERE_SORTBYGROUP)
+        && pWInfo->nOBSat==pWInfo->pOrderBy->nExpr && nLoop>0
+    ){
+      Bitmask revMask = 0;
+      int nOrder = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy,
+          pFrom, 0, nLoop-1, pFrom->aLoop[nLoop-1], &revMask
+      );
+      assert( pWInfo->sorted==0 );
+      if( nOrder==pWInfo->pOrderBy->nExpr ){
+        pWInfo->sorted = 1;
+        pWInfo->revMask = revMask;
+      }
+    }
+  }
+
+  pWInfo->nRowOut = pFrom->nRow;
+#ifdef WHERETRACE_ENABLED
+  pWInfo->rTotalCost = pFrom->rCost;
+#endif
+
+  /* Free temporary memory and return success */
+  sqlite3StackFreeNN(pParse->db, pSpace);
+  return SQLITE_OK;
+}
+
+/*
+** This routine implements a heuristic designed to improve query planning.
+** This routine is called in between the first and second call to
+** wherePathSolver().  Hence the name "Interstage" "Heuristic".
+**
+** The first call to wherePathSolver() (hereafter just "solver()") computes
+** the best path without regard to the order of the outputs.  The second call
+** to the solver() builds upon the first call to try to find an alternative
+** path that satisfies the ORDER BY clause.
+**
+** This routine looks at the results of the first solver() run, and for
+** every FROM clause term in the resulting query plan that uses an equality
+** constraint against an index, disable other WhereLoops for that same
+** FROM clause term that would try to do a full-table scan.  This prevents
+** an index search from being converted into a full-table scan in order to
+** satisfy an ORDER BY clause, since even though we might get slightly better
+** performance using the full-scan without sorting if the output size
+** estimates are very precise, we might also get severe performance
+** degradation using the full-scan if the output size estimate is too large.
+** It is better to err on the side of caution.
+**
+** Except, if the first solver() call generated a full-table scan in an outer
+** loop then stop this analysis at the first full-scan, since the second
+** solver() run might try to swap that full-scan for another in order to
+** get the output into the correct order.  In other words, we allow a
+** rewrite like this:
+**
+**     First Solver()                      Second Solver()
+**       |-- SCAN t1                         |-- SCAN t2
+**       |-- SEARCH t2                       `-- SEARCH t1
+**       `-- SORT USING B-TREE
+**
+** The purpose of this routine is to disallow rewrites such as:
+**
+**     First Solver()                      Second Solver()
+**       |-- SEARCH t1                       |-- SCAN t2     <--- bad!
+**       |-- SEARCH t2                       `-- SEARCH t1
+**       `-- SORT USING B-TREE
+**
+** See test cases in test/whereN.test for the real-world query that
+** originally provoked this heuristic.
+*/
+static SQLITE_NOINLINE void whereInterstageHeuristic(WhereInfo *pWInfo){
+  int i;
+#ifdef WHERETRACE_ENABLED
+  int once = 0;
+#endif
+  for(i=0; i<pWInfo->nLevel; i++){
+    WhereLoop *p = pWInfo->a[i].pWLoop;
+    if( p==0 ) break;
+    if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 ) continue;
+    if( (p->wsFlags & (WHERE_COLUMN_EQ|WHERE_COLUMN_NULL|WHERE_COLUMN_IN))!=0 ){
+      u8 iTab = p->iTab;
+      WhereLoop *pLoop;
+      for(pLoop=pWInfo->pLoops; pLoop; pLoop=pLoop->pNextLoop){
+        if( pLoop->iTab!=iTab ) continue;
+        if( (pLoop->wsFlags & (WHERE_CONSTRAINT|WHERE_AUTO_INDEX))!=0 ){
+          /* Auto-index and index-constrained loops allowed to remain */
+          continue;
+        }
+#ifdef WHERETRACE_ENABLED
+        if( sqlite3WhereTrace & 0x80 ){
+          if( once==0 ){
+            sqlite3DebugPrintf("Loops disabled by interstage heuristic:\n");
+            once = 1;
+          }
+          sqlite3WhereLoopPrint(pLoop, &pWInfo->sWC);
+        }
+#endif /* WHERETRACE_ENABLED */
+        pLoop->prereq = ALLBITS;  /* Prevent 2nd solver() from using this one */
+      }
+    }else{
+      break;
+    }
+  }
+}
+
+/*
+** Most queries use only a single table (they are not joins) and have
+** simple == constraints against indexed fields.  This routine attempts
+** to plan those simple cases using much less ceremony than the
+** general-purpose query planner, and thereby yield faster sqlite3_prepare()
+** times for the common case.
+**
+** Return non-zero on success, if this query can be handled by this
+** no-frills query planner.  Return zero if this query needs the
+** general-purpose query planner.
+*/
+static int whereShortCut(WhereLoopBuilder *pBuilder){
+  WhereInfo *pWInfo;
+  SrcItem *pItem;
+  WhereClause *pWC;
+  WhereTerm *pTerm;
+  WhereLoop *pLoop;
+  int iCur;
+  int j;
+  Table *pTab;
+  Index *pIdx;
+  WhereScan scan;
+
+  pWInfo = pBuilder->pWInfo;
+  if( pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE ) return 0;
+  assert( pWInfo->pTabList->nSrc>=1 );
+  pItem = pWInfo->pTabList->a;
+  pTab = pItem->pSTab;
+  if( IsVirtual(pTab) ) return 0;
+  if( pItem->fg.isIndexedBy || pItem->fg.notIndexed ){
+    testcase( pItem->fg.isIndexedBy );
+    testcase( pItem->fg.notIndexed );
+    return 0;
+  }
+  iCur = pItem->iCursor;
+  pWC = &pWInfo->sWC;
+  pLoop = pBuilder->pNew;
+  pLoop->wsFlags = 0;
+  pLoop->nSkip = 0;
+  pTerm = whereScanInit(&scan, pWC, iCur, -1, WO_EQ|WO_IS, 0);
+  while( pTerm && pTerm->prereqRight ) pTerm = whereScanNext(&scan);
+  if( pTerm ){
+    testcase( pTerm->eOperator & WO_IS );
+    pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW;
+    pLoop->aLTerm[0] = pTerm;
+    pLoop->nLTerm = 1;
+    pLoop->u.btree.nEq = 1;
+    /* TUNING: Cost of a rowid lookup is 10 */
+    pLoop->rRun = 33;  /* 33==sqlite3LogEst(10) */
+  }else{
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      int opMask;
+      assert( pLoop->aLTermSpace==pLoop->aLTerm );
+      if( !IsUniqueIndex(pIdx)
+       || pIdx->pPartIdxWhere!=0
+       || pIdx->nKeyCol>ArraySize(pLoop->aLTermSpace)
+      ) continue;
+      opMask = pIdx->uniqNotNull ? (WO_EQ|WO_IS) : WO_EQ;
+      for(j=0; j<pIdx->nKeyCol; j++){
+        pTerm = whereScanInit(&scan, pWC, iCur, j, opMask, pIdx);
+        while( pTerm && pTerm->prereqRight ) pTerm = whereScanNext(&scan);
+        if( pTerm==0 ) break;
+        testcase( pTerm->eOperator & WO_IS );
+        pLoop->aLTerm[j] = pTerm;
+      }
+      if( j!=pIdx->nKeyCol ) continue;
+      pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_ONEROW|WHERE_INDEXED;
+      if( pIdx->isCovering || (pItem->colUsed & pIdx->colNotIdxed)==0 ){
+        pLoop->wsFlags |= WHERE_IDX_ONLY;
+      }
+      pLoop->nLTerm = j;
+      pLoop->u.btree.nEq = j;
+      pLoop->u.btree.pIndex = pIdx;
+      /* TUNING: Cost of a unique index lookup is 15 */
+      pLoop->rRun = 39;  /* 39==sqlite3LogEst(15) */
+      break;
+    }
+  }
+  if( pLoop->wsFlags ){
+    pLoop->nOut = (LogEst)1;
+    pWInfo->a[0].pWLoop = pLoop;
+    assert( pWInfo->sMaskSet.n==1 && iCur==pWInfo->sMaskSet.ix[0] );
+    pLoop->maskSelf = 1; /* sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur); */
+    pWInfo->a[0].iTabCur = iCur;
+    pWInfo->nRowOut = 1;
+    if( pWInfo->pOrderBy ) pWInfo->nOBSat =  pWInfo->pOrderBy->nExpr;
+    if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
+      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+    }
+    if( scan.iEquiv>1 ) pLoop->wsFlags |= WHERE_TRANSCONS;
+#ifdef SQLITE_DEBUG
+    pLoop->cId = '0';
+#endif
+#ifdef WHERETRACE_ENABLED
+    if( sqlite3WhereTrace & 0x02 ){
+      sqlite3DebugPrintf("whereShortCut() used to compute solution\n");
+    }
+#endif
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Helper function for exprIsDeterministic().
+*/
+static int exprNodeIsDeterministic(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_FUNCTION && ExprHasProperty(pExpr, EP_ConstFunc)==0 ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Return true if the expression contains no non-deterministic SQL
+** functions. Do not consider non-deterministic SQL functions that are
+** part of sub-select statements.
+*/
+static int exprIsDeterministic(Expr *p){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.eCode = 1;
+  w.xExprCallback = exprNodeIsDeterministic;
+  w.xSelectCallback = sqlite3SelectWalkFail;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+
+#ifdef WHERETRACE_ENABLED
+/*
+** Display all WhereLoops in pWInfo
+*/
+static void showAllWhereLoops(WhereInfo *pWInfo, WhereClause *pWC){
+  if( sqlite3WhereTrace ){    /* Display all of the WhereLoop objects */
+    WhereLoop *p;
+    int i;
+    static const char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz"
+                                           "ABCDEFGHIJKLMNOPQRSTUVWYXZ";
+    for(p=pWInfo->pLoops, i=0; p; p=p->pNextLoop, i++){
+      p->cId = zLabel[i%(sizeof(zLabel)-1)];
+      sqlite3WhereLoopPrint(p, pWC);
+    }
+  }
+}
+# define WHERETRACE_ALL_LOOPS(W,C) showAllWhereLoops(W,C)
+#else
+# define WHERETRACE_ALL_LOOPS(W,C)
+#endif
+
+/* Attempt to omit tables from a join that do not affect the result.
+** For a table to not affect the result, the following must be true:
+**
+**   1) The query must not be an aggregate.
+**   2) The table must be the RHS of a LEFT JOIN.
+**   3) Either the query must be DISTINCT, or else the ON or USING clause
+**      must contain a constraint that limits the scan of the table to
+**      at most a single row.
+**   4) The table must not be referenced by any part of the query apart
+**      from its own USING or ON clause.
+**   5) The table must not have an inner-join ON or USING clause if there is
+**      a RIGHT JOIN anywhere in the query.  Otherwise the ON/USING clause
+**      might move from the right side to the left side of the RIGHT JOIN.
+**      Note: Due to (2), this condition can only arise if the table is
+**      the right-most table of a subquery that was flattened into the
+**      main query and that subquery was the right-hand operand of an
+**      inner join that held an ON or USING clause.
+**   6) The ORDER BY clause has 63 or fewer terms
+**   7) The omit-noop-join optimization is enabled.
+**
+** Items (1), (6), and (7) are checked by the caller.
+**
+** For example, given:
+**
+**     CREATE TABLE t1(ipk INTEGER PRIMARY KEY, v1);
+**     CREATE TABLE t2(ipk INTEGER PRIMARY KEY, v2);
+**     CREATE TABLE t3(ipk INTEGER PRIMARY KEY, v3);
+**
+** then table t2 can be omitted from the following:
+**
+**     SELECT v1, v3 FROM t1
+**       LEFT JOIN t2 ON (t1.ipk=t2.ipk)
+**       LEFT JOIN t3 ON (t1.ipk=t3.ipk)
+**
+** or from:
+**
+**     SELECT DISTINCT v1, v3 FROM t1
+**       LEFT JOIN t2
+**       LEFT JOIN t3 ON (t1.ipk=t3.ipk)
+*/
+static SQLITE_NOINLINE Bitmask whereOmitNoopJoin(
+  WhereInfo *pWInfo,
+  Bitmask notReady
+){
+  int i;
+  Bitmask tabUsed;
+  int hasRightJoin;
+
+  /* Preconditions checked by the caller */
+  assert( pWInfo->nLevel>=2 );
+  assert( OptimizationEnabled(pWInfo->pParse->db, SQLITE_OmitNoopJoin) );
+
+  /* These two preconditions checked by the caller combine to guarantee
+  ** condition (1) of the header comment */
+  assert( pWInfo->pResultSet!=0 );
+  assert( 0==(pWInfo->wctrlFlags & WHERE_AGG_DISTINCT) );
+
+  tabUsed = sqlite3WhereExprListUsage(&pWInfo->sMaskSet, pWInfo->pResultSet);
+  if( pWInfo->pOrderBy ){
+    tabUsed |= sqlite3WhereExprListUsage(&pWInfo->sMaskSet, pWInfo->pOrderBy);
+  }
+  hasRightJoin = (pWInfo->pTabList->a[0].fg.jointype & JT_LTORJ)!=0;
+  for(i=pWInfo->nLevel-1; i>=1; i--){
+    WhereTerm *pTerm, *pEnd;
+    SrcItem *pItem;
+    WhereLoop *pLoop;
+    Bitmask m1;
+    pLoop = pWInfo->a[i].pWLoop;
+    pItem = &pWInfo->pTabList->a[pLoop->iTab];
+    if( (pItem->fg.jointype & (JT_LEFT|JT_RIGHT))!=JT_LEFT ) continue;
+    if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)==0
+     && (pLoop->wsFlags & WHERE_ONEROW)==0
+    ){
+      continue;
+    }
+    if( (tabUsed & pLoop->maskSelf)!=0 ) continue;
+    pEnd = pWInfo->sWC.a + pWInfo->sWC.nTerm;
+    for(pTerm=pWInfo->sWC.a; pTerm<pEnd; pTerm++){
+      if( (pTerm->prereqAll & pLoop->maskSelf)!=0 ){
+        if( !ExprHasProperty(pTerm->pExpr, EP_OuterON)
+         || pTerm->pExpr->w.iJoin!=pItem->iCursor
+        ){
+          break;
+        }
+      }
+      if( hasRightJoin
+       && ExprHasProperty(pTerm->pExpr, EP_InnerON)
+       && NEVER(pTerm->pExpr->w.iJoin==pItem->iCursor)
+      ){
+        break;  /* restriction (5) */
+      }
+    }
+    if( pTerm<pEnd ) continue;
+    WHERETRACE(0xffffffff,("-> omit unused FROM-clause term %c\n",pLoop->cId));
+    m1 = MASKBIT(i)-1;
+    testcase( ((pWInfo->revMask>>1) & ~m1)!=0 );
+    pWInfo->revMask = (m1 & pWInfo->revMask) | ((pWInfo->revMask>>1) & ~m1);
+    notReady &= ~pLoop->maskSelf;
+    for(pTerm=pWInfo->sWC.a; pTerm<pEnd; pTerm++){
+      if( (pTerm->prereqAll & pLoop->maskSelf)!=0 ){
+        pTerm->wtFlags |= TERM_CODED;
+      }
+    }
+    if( i!=pWInfo->nLevel-1 ){
+      int nByte = (pWInfo->nLevel-1-i) * sizeof(WhereLevel);
+      memmove(&pWInfo->a[i], &pWInfo->a[i+1], nByte);
+    }
+    pWInfo->nLevel--;
+    assert( pWInfo->nLevel>0 );
+  }
+  return notReady;
+}
+
+/*
+** Check to see if there are any SEARCH loops that might benefit from
+** using a Bloom filter.  Consider a Bloom filter if:
+**
+**   (1)  The SEARCH happens more than N times where N is the number
+**        of rows in the table that is being considered for the Bloom
+**        filter.
+**   (2)  Some searches are expected to find zero rows.  (This is determined
+**        by the WHERE_SELFCULL flag on the term.)
+**   (3)  Bloom-filter processing is not disabled.  (Checked by the
+**        caller.)
+**   (4)  The size of the table being searched is known by ANALYZE.
+**
+** This block of code merely checks to see if a Bloom filter would be
+** appropriate, and if so sets the WHERE_BLOOMFILTER flag on the
+** WhereLoop.  The implementation of the Bloom filter comes further
+** down where the code for each WhereLoop is generated.
+*/
+static SQLITE_NOINLINE void whereCheckIfBloomFilterIsUseful(
+  const WhereInfo *pWInfo
+){
+  int i;
+  LogEst nSearch = 0;
+
+  assert( pWInfo->nLevel>=2 );
+  assert( OptimizationEnabled(pWInfo->pParse->db, SQLITE_BloomFilter) );
+  for(i=0; i<pWInfo->nLevel; i++){
+    WhereLoop *pLoop = pWInfo->a[i].pWLoop;
+    const unsigned int reqFlags = (WHERE_SELFCULL|WHERE_COLUMN_EQ);
+    SrcItem *pItem = &pWInfo->pTabList->a[pLoop->iTab];
+    Table *pTab = pItem->pSTab;
+    if( (pTab->tabFlags & TF_HasStat1)==0 ) break;
+    pTab->tabFlags |= TF_MaybeReanalyze;
+    if( i>=1
+     && (pLoop->wsFlags & reqFlags)==reqFlags
+     /* vvvvvv--- Always the case if WHERE_COLUMN_EQ is defined */
+     && ALWAYS((pLoop->wsFlags & (WHERE_IPK|WHERE_INDEXED))!=0)
+    ){
+      if( nSearch > pTab->nRowLogEst ){
+        testcase( pItem->fg.jointype & JT_LEFT );
+        pLoop->wsFlags |= WHERE_BLOOMFILTER;
+        pLoop->wsFlags &= ~WHERE_IDX_ONLY;
+        WHERETRACE(0xffffffff, (
+           "-> use Bloom-filter on loop %c because there are ~%.1e "
+           "lookups into %s which has only ~%.1e rows\n",
+           pLoop->cId, (double)sqlite3LogEstToInt(nSearch), pTab->zName,
+           (double)sqlite3LogEstToInt(pTab->nRowLogEst)));
+      }
+    }
+    nSearch += pLoop->nOut;
+  }
+}
+
+/*
+** The index pIdx is used by a query and contains one or more expressions.
+** In other words pIdx is an index on an expression.  iIdxCur is the cursor
+** number for the index and iDataCur is the cursor number for the corresponding
+** table.
+**
+** This routine adds IndexedExpr entries to the Parse->pIdxEpr field for
+** each of the expressions in the index so that the expression code generator
+** will know to replace occurrences of the indexed expression with
+** references to the corresponding column of the index.
+*/
+static SQLITE_NOINLINE void whereAddIndexedExpr(
+  Parse *pParse,     /* Add IndexedExpr entries to pParse->pIdxEpr */
+  Index *pIdx,       /* The index-on-expression that contains the expressions */
+  int iIdxCur,       /* Cursor number for pIdx */
+  SrcItem *pTabItem  /* The FROM clause entry for the table */
+){
+  int i;
+  IndexedExpr *p;
+  Table *pTab;
+  assert( pIdx->bHasExpr );
+  pTab = pIdx->pTable;
+  for(i=0; i<pIdx->nColumn; i++){
+    Expr *pExpr;
+    int j = pIdx->aiColumn[i];
+    if( j==XN_EXPR ){
+      pExpr = pIdx->aColExpr->a[i].pExpr;
+    }else if( j>=0 && (pTab->aCol[j].colFlags & COLFLAG_VIRTUAL)!=0 ){
+      pExpr = sqlite3ColumnExpr(pTab, &pTab->aCol[j]);
+    }else{
+      continue;
+    }
+    if( sqlite3ExprIsConstant(0,pExpr) ) continue;
+    p = sqlite3DbMallocRaw(pParse->db,  sizeof(IndexedExpr));
+    if( p==0 ) break;
+    p->pIENext = pParse->pIdxEpr;
+#ifdef WHERETRACE_ENABLED
+    if( sqlite3WhereTrace & 0x200 ){
+      sqlite3DebugPrintf("New pParse->pIdxEpr term {%d,%d}\n", iIdxCur, i);
+      if( sqlite3WhereTrace & 0x5000 ) sqlite3ShowExpr(pExpr);
+    }
+#endif
+    p->pExpr = sqlite3ExprDup(pParse->db, pExpr, 0);
+    p->iDataCur = pTabItem->iCursor;
+    p->iIdxCur = iIdxCur;
+    p->iIdxCol = i;
+    p->bMaybeNullRow = (pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0;
+    if( sqlite3IndexAffinityStr(pParse->db, pIdx) ){
+      p->aff = pIdx->zColAff[i];
+    }
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+    p->zIdxName = pIdx->zName;
+#endif
+    pParse->pIdxEpr = p;
+    if( p->pIENext==0 ){
+      void *pArg = (void*)&pParse->pIdxEpr;
+      sqlite3ParserAddCleanup(pParse, whereIndexedExprCleanup, pArg);
+    }
+  }
+}
+
+/*
+** Set the reverse-scan order mask to one for all tables in the query
+** with the exception of MATERIALIZED common table expressions that have
+** their own internal ORDER BY clauses.
+**
+** This implements the PRAGMA reverse_unordered_selects=ON setting.
+** (Also SQLITE_DBCONFIG_REVERSE_SCANORDER).
+*/
+static SQLITE_NOINLINE void whereReverseScanOrder(WhereInfo *pWInfo){
+  int ii;
+  for(ii=0; ii<pWInfo->pTabList->nSrc; ii++){
+    SrcItem *pItem = &pWInfo->pTabList->a[ii];
+    if( !pItem->fg.isCte
+     || pItem->u2.pCteUse->eM10d!=M10d_Yes
+     || NEVER(pItem->fg.isSubquery==0)
+     || pItem->u4.pSubq->pSelect->pOrderBy==0
+    ){
+      pWInfo->revMask |= MASKBIT(ii);
+    }
+  }
+}
+
+/*
+** Generate the beginning of the loop used for WHERE clause processing.
+** The return value is a pointer to an opaque structure that contains
+** information needed to terminate the loop.  Later, the calling routine
+** should invoke sqlite3WhereEnd() with the return value of this function
+** in order to complete the WHERE clause processing.
+**
+** If an error occurs, this routine returns NULL.
+**
+** The basic idea is to do a nested loop, one loop for each table in
+** the FROM clause of a select.  (INSERT and UPDATE statements are the
+** same as a SELECT with only a single table in the FROM clause.)  For
+** example, if the SQL is this:
+**
+**       SELECT * FROM t1, t2, t3 WHERE ...;
+**
+** Then the code generated is conceptually like the following:
+**
+**      foreach row1 in t1 do       \    Code generated
+**        foreach row2 in t2 do      |-- by sqlite3WhereBegin()
+**          foreach row3 in t3 do   /
+**            ...
+**          end                     \    Code generated
+**        end                        |-- by sqlite3WhereEnd()
+**      end                         /
+**
+** Note that the loops might not be nested in the order in which they
+** appear in the FROM clause if a different order is better able to make
+** use of indices.  Note also that when the IN operator appears in
+** the WHERE clause, it might result in additional nested loops for
+** scanning through all values on the right-hand side of the IN.
+**
+** There are Btree cursors associated with each table.  t1 uses cursor
+** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
+** And so forth.  This routine generates code to open those VDBE cursors
+** and sqlite3WhereEnd() generates the code to close them.
+**
+** The code that sqlite3WhereBegin() generates leaves the cursors named
+** in pTabList pointing at their appropriate entries.  The [...] code
+** can use OP_Column and OP_Rowid opcodes on these cursors to extract
+** data from the various tables of the loop.
+**
+** If the WHERE clause is empty, the foreach loops must each scan their
+** entire tables.  Thus a three-way join is an O(N^3) operation.  But if
+** the tables have indices and there are terms in the WHERE clause that
+** refer to those indices, a complete table scan can be avoided and the
+** code will run much faster.  Most of the work of this routine is checking
+** to see if there are indices that can be used to speed up the loop.
+**
+** Terms of the WHERE clause are also used to limit which rows actually
+** make it to the "..." in the middle of the loop.  After each "foreach",
+** terms of the WHERE clause that use only terms in that loop and outer
+** loops are evaluated and if false a jump is made around all subsequent
+** inner loops (or around the "..." if the test occurs within the inner-
+** most loop)
+**
+** OUTER JOINS
+**
+** An outer join of tables t1 and t2 is conceptually coded as follows:
+**
+**    foreach row1 in t1 do
+**      flag = 0
+**      foreach row2 in t2 do
+**        start:
+**          ...
+**          flag = 1
+**      end
+**      if flag==0 then
+**        move the row2 cursor to a null row
+**        goto start
+**      fi
+**    end
+**
+** ORDER BY CLAUSE PROCESSING
+**
+** pOrderBy is a pointer to the ORDER BY clause (or the GROUP BY clause
+** if the WHERE_GROUPBY flag is set in wctrlFlags) of a SELECT statement
+** if there is one.  If there is no ORDER BY clause or if this routine
+** is called from an UPDATE or DELETE statement, then pOrderBy is NULL.
+**
+** The iIdxCur parameter is the cursor number of an index.  If
+** WHERE_OR_SUBCLAUSE is set, iIdxCur is the cursor number of an index
+** to use for OR clause processing.  The WHERE clause should use this
+** specific cursor.  If WHERE_ONEPASS_DESIRED is set, then iIdxCur is
+** the first cursor in an array of cursors for all indices.  iIdxCur should
+** be used to compute the appropriate cursor depending on which index is
+** used.
+*/
+SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
+  Parse *pParse,          /* The parser context */
+  SrcList *pTabList,      /* FROM clause: A list of all tables to be scanned */
+  Expr *pWhere,           /* The WHERE clause */
+  ExprList *pOrderBy,     /* An ORDER BY (or GROUP BY) clause, or NULL */
+  ExprList *pResultSet,   /* Query result set.  Req'd for DISTINCT */
+  Select *pSelect,        /* The entire SELECT statement */
+  u16 wctrlFlags,         /* The WHERE_* flags defined in sqliteInt.h */
+  int iAuxArg             /* If WHERE_OR_SUBCLAUSE is set, index cursor number
+                          ** If WHERE_USE_LIMIT, then the limit amount */
+){
+  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
+  int nTabList;              /* Number of elements in pTabList */
+  WhereInfo *pWInfo;         /* Will become the return value of this function */
+  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
+  Bitmask notReady;          /* Cursors that are not yet positioned */
+  WhereLoopBuilder sWLB;     /* The WhereLoop builder */
+  WhereMaskSet *pMaskSet;    /* The expression mask set */
+  WhereLevel *pLevel;        /* A single level in pWInfo->a[] */
+  WhereLoop *pLoop;          /* Pointer to a single WhereLoop object */
+  int ii;                    /* Loop counter */
+  sqlite3 *db;               /* Database connection */
+  int rc;                    /* Return code */
+  u8 bFordelete = 0;         /* OPFLAG_FORDELETE or zero, as appropriate */
+
+  assert( (wctrlFlags & WHERE_ONEPASS_MULTIROW)==0 || (
+        (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0
+     && (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
+  ));
+
+  /* Only one of WHERE_OR_SUBCLAUSE or WHERE_USE_LIMIT */
+  assert( (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
+            || (wctrlFlags & WHERE_USE_LIMIT)==0 );
+
+  /* Variable initialization */
+  db = pParse->db;
+  memset(&sWLB, 0, sizeof(sWLB));
+
+  /* An ORDER/GROUP BY clause of more than 63 terms cannot be optimized */
+  testcase( pOrderBy && pOrderBy->nExpr==BMS-1 );
+  if( pOrderBy && pOrderBy->nExpr>=BMS ){
+    pOrderBy = 0;
+    wctrlFlags &= ~WHERE_WANT_DISTINCT;
+    wctrlFlags |= WHERE_KEEP_ALL_JOINS; /* Disable omit-noop-join opt */
+  }
+
+  /* The number of tables in the FROM clause is limited by the number of
+  ** bits in a Bitmask
+  */
+  testcase( pTabList->nSrc==BMS );
+  if( pTabList->nSrc>BMS ){
+    sqlite3ErrorMsg(pParse, "at most %d tables in a join", BMS);
+    return 0;
+  }
+
+  /* This function normally generates a nested loop for all tables in
+  ** pTabList.  But if the WHERE_OR_SUBCLAUSE flag is set, then we should
+  ** only generate code for the first table in pTabList and assume that
+  ** any cursors associated with subsequent tables are uninitialized.
+  */
+  nTabList = (wctrlFlags & WHERE_OR_SUBCLAUSE) ? 1 : pTabList->nSrc;
+
+  /* Allocate and initialize the WhereInfo structure that will become the
+  ** return value. A single allocation is used to store the WhereInfo
+  ** struct, the contents of WhereInfo.a[], the WhereClause structure
+  ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
+  ** field (type Bitmask) it must be aligned on an 8-byte boundary on
+  ** some architectures. Hence the ROUND8() below.
+  */
+  nByteWInfo = ROUND8P(sizeof(WhereInfo));
+  if( nTabList>1 ){
+    nByteWInfo = ROUND8P(nByteWInfo + (nTabList-1)*sizeof(WhereLevel));
+  }
+  pWInfo = sqlite3DbMallocRawNN(db, nByteWInfo + sizeof(WhereLoop));
+  if( db->mallocFailed ){
+    sqlite3DbFree(db, pWInfo);
+    pWInfo = 0;
+    goto whereBeginError;
+  }
+  pWInfo->pParse = pParse;
+  pWInfo->pTabList = pTabList;
+  pWInfo->pOrderBy = pOrderBy;
+#if WHERETRACE_ENABLED
+  pWInfo->pWhere = pWhere;
+#endif
+  pWInfo->pResultSet = pResultSet;
+  pWInfo->aiCurOnePass[0] = pWInfo->aiCurOnePass[1] = -1;
+  pWInfo->nLevel = nTabList;
+  pWInfo->iBreak = pWInfo->iContinue = sqlite3VdbeMakeLabel(pParse);
+  pWInfo->wctrlFlags = wctrlFlags;
+  pWInfo->iLimit = iAuxArg;
+  pWInfo->savedNQueryLoop = pParse->nQueryLoop;
+  pWInfo->pSelect = pSelect;
+  memset(&pWInfo->nOBSat, 0,
+         offsetof(WhereInfo,sWC) - offsetof(WhereInfo,nOBSat));
+  memset(&pWInfo->a[0], 0, sizeof(WhereLoop)+nTabList*sizeof(WhereLevel));
+  assert( pWInfo->eOnePass==ONEPASS_OFF );  /* ONEPASS defaults to OFF */
+  pMaskSet = &pWInfo->sMaskSet;
+  pMaskSet->n = 0;
+  pMaskSet->ix[0] = -99; /* Initialize ix[0] to a value that can never be
+                         ** a valid cursor number, to avoid an initial
+                         ** test for pMaskSet->n==0 in sqlite3WhereGetMask() */
+  sWLB.pWInfo = pWInfo;
+  sWLB.pWC = &pWInfo->sWC;
+  sWLB.pNew = (WhereLoop*)(((char*)pWInfo)+nByteWInfo);
+  assert( EIGHT_BYTE_ALIGNMENT(sWLB.pNew) );
+  whereLoopInit(sWLB.pNew);
+#ifdef SQLITE_DEBUG
+  sWLB.pNew->cId = '*';
+#endif
+
+  /* Split the WHERE clause into separate subexpressions where each
+  ** subexpression is separated by an AND operator.
+  */
+  sqlite3WhereClauseInit(&pWInfo->sWC, pWInfo);
+  sqlite3WhereSplit(&pWInfo->sWC, pWhere, TK_AND);
+
+  /* Special case: No FROM clause
+  */
+  if( nTabList==0 ){
+    if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr;
+    if( (wctrlFlags & WHERE_WANT_DISTINCT)!=0
+     && OptimizationEnabled(db, SQLITE_DistinctOpt)
+    ){
+      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+    }
+    if( ALWAYS(pWInfo->pSelect)
+     && (pWInfo->pSelect->selFlags & SF_MultiValue)==0
+    ){
+      ExplainQueryPlan((pParse, 0, "SCAN CONSTANT ROW"));
+    }
+  }else{
+    /* Assign a bit from the bitmask to every term in the FROM clause.
+    **
+    ** The N-th term of the FROM clause is assigned a bitmask of 1<<N.
+    **
+    ** The rule of the previous sentence ensures that if X is the bitmask for
+    ** a table T, then X-1 is the bitmask for all other tables to the left of T.
+    ** Knowing the bitmask for all tables to the left of a left join is
+    ** important.  Ticket #3015.
+    **
+    ** Note that bitmasks are created for all pTabList->nSrc tables in
+    ** pTabList, not just the first nTabList tables.  nTabList is normally
+    ** equal to pTabList->nSrc but might be shortened to 1 if the
+    ** WHERE_OR_SUBCLAUSE flag is set.
+    */
+    ii = 0;
+    do{
+      createMask(pMaskSet, pTabList->a[ii].iCursor);
+      sqlite3WhereTabFuncArgs(pParse, &pTabList->a[ii], &pWInfo->sWC);
+    }while( (++ii)<pTabList->nSrc );
+  #ifdef SQLITE_DEBUG
+    {
+      Bitmask mx = 0;
+      for(ii=0; ii<pTabList->nSrc; ii++){
+        Bitmask m = sqlite3WhereGetMask(pMaskSet, pTabList->a[ii].iCursor);
+        assert( m>=mx );
+        mx = m;
+      }
+    }
+  #endif
+  }
+
+  /* Analyze all of the subexpressions. */
+  sqlite3WhereExprAnalyze(pTabList, &pWInfo->sWC);
+  if( pSelect && pSelect->pLimit ){
+    sqlite3WhereAddLimit(&pWInfo->sWC, pSelect);
+  }
+  if( pParse->nErr ) goto whereBeginError;
+
+  /* The False-WHERE-Term-Bypass optimization:
+  **
+  ** If there are WHERE terms that are false, then no rows will be output,
+  ** so skip over all of the code generated here.
+  **
+  ** Conditions:
+  **
+  **   (1)  The WHERE term must not refer to any tables in the join.
+  **   (2)  The term must not come from an ON clause on the
+  **        right-hand side of a LEFT or FULL JOIN.
+  **   (3)  The term must not come from an ON clause, or there must be
+  **        no RIGHT or FULL OUTER joins in pTabList.
+  **   (4)  If the expression contains non-deterministic functions
+  **        that are not within a sub-select. This is not required
+  **        for correctness but rather to preserves SQLite's legacy
+  **        behaviour in the following two cases:
+  **
+  **          WHERE random()>0;           -- eval random() once per row
+  **          WHERE (SELECT random())>0;  -- eval random() just once overall
+  **
+  ** Note that the Where term need not be a constant in order for this
+  ** optimization to apply, though it does need to be constant relative to
+  ** the current subquery (condition 1).  The term might include variables
+  ** from outer queries so that the value of the term changes from one
+  ** invocation of the current subquery to the next.
+  */
+  for(ii=0; ii<sWLB.pWC->nBase; ii++){
+    WhereTerm *pT = &sWLB.pWC->a[ii];  /* A term of the WHERE clause */
+    Expr *pX;                          /* The expression of pT */
+    if( pT->wtFlags & TERM_VIRTUAL ) continue;
+    pX = pT->pExpr;
+    assert( pX!=0 );
+    assert( pT->prereqAll!=0 || !ExprHasProperty(pX, EP_OuterON) );
+    if( pT->prereqAll==0                           /* Conditions (1) and (2) */
+     && (nTabList==0 || exprIsDeterministic(pX))   /* Condition (4) */
+     && !(ExprHasProperty(pX, EP_InnerON)          /* Condition (3) */
+          && (pTabList->a[0].fg.jointype & JT_LTORJ)!=0 )
+    ){
+      sqlite3ExprIfFalse(pParse, pX, pWInfo->iBreak, SQLITE_JUMPIFNULL);
+      pT->wtFlags |= TERM_CODED;
+    }
+  }
+
+  if( wctrlFlags & WHERE_WANT_DISTINCT ){
+    if( OptimizationDisabled(db, SQLITE_DistinctOpt) ){
+      /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via
+      ** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */
+      wctrlFlags &= ~WHERE_WANT_DISTINCT;
+      pWInfo->wctrlFlags &= ~WHERE_WANT_DISTINCT;
+    }else if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
+      /* The DISTINCT marking is pointless.  Ignore it. */
+      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+    }else if( pOrderBy==0 ){
+      /* Try to ORDER BY the result set to make distinct processing easier */
+      pWInfo->wctrlFlags |= WHERE_DISTINCTBY;
+      pWInfo->pOrderBy = pResultSet;
+    }
+  }
+
+  /* Construct the WhereLoop objects */
+#if defined(WHERETRACE_ENABLED)
+  if( sqlite3WhereTrace & 0xffffffff ){
+    sqlite3DebugPrintf("*** Optimizer Start *** (wctrlFlags: 0x%x",wctrlFlags);
+    if( wctrlFlags & WHERE_USE_LIMIT ){
+      sqlite3DebugPrintf(", limit: %d", iAuxArg);
+    }
+    sqlite3DebugPrintf(")\n");
+    if( sqlite3WhereTrace & 0x8000 ){
+      Select sSelect;
+      memset(&sSelect, 0, sizeof(sSelect));
+      sSelect.selFlags = SF_WhereBegin;
+      sSelect.pSrc = pTabList;
+      sSelect.pWhere = pWhere;
+      sSelect.pOrderBy = pOrderBy;
+      sSelect.pEList = pResultSet;
+      sqlite3TreeViewSelect(0, &sSelect, 0);
+    }
+    if( sqlite3WhereTrace & 0x4000 ){ /* Display all WHERE clause terms */
+      sqlite3DebugPrintf("---- WHERE clause at start of analysis:\n");
+      sqlite3WhereClausePrint(sWLB.pWC);
+    }
+  }
+#endif
+
+  if( nTabList!=1 || whereShortCut(&sWLB)==0 ){
+    rc = whereLoopAddAll(&sWLB);
+    if( rc ) goto whereBeginError;
+
+#ifdef SQLITE_ENABLE_STAT4
+    /* If one or more WhereTerm.truthProb values were used in estimating
+    ** loop parameters, but then those truthProb values were subsequently
+    ** changed based on STAT4 information while computing subsequent loops,
+    ** then we need to rerun the whole loop building process so that all
+    ** loops will be built using the revised truthProb values. */
+    if( sWLB.bldFlags2 & SQLITE_BLDF2_2NDPASS ){
+      WHERETRACE_ALL_LOOPS(pWInfo, sWLB.pWC);
+      WHERETRACE(0xffffffff,
+           ("**** Redo all loop computations due to"
+            " TERM_HIGHTRUTH changes ****\n"));
+      while( pWInfo->pLoops ){
+        WhereLoop *p = pWInfo->pLoops;
+        pWInfo->pLoops = p->pNextLoop;
+        whereLoopDelete(db, p);
+      }
+      rc = whereLoopAddAll(&sWLB);
+      if( rc ) goto whereBeginError;
+    }
+#endif
+    WHERETRACE_ALL_LOOPS(pWInfo, sWLB.pWC);
+
+    wherePathSolver(pWInfo, 0);
+    if( db->mallocFailed ) goto whereBeginError;
+    if( pWInfo->pOrderBy ){
+       whereInterstageHeuristic(pWInfo);
+       wherePathSolver(pWInfo, pWInfo->nRowOut<0 ? 1 : pWInfo->nRowOut+1);
+       if( db->mallocFailed ) goto whereBeginError;
+    }
+
+    /* TUNING:  Assume that a DISTINCT clause on a subquery reduces
+    ** the output size by a factor of 8 (LogEst -30).
+    */
+    if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0 ){
+      WHERETRACE(0x0080,("nRowOut reduced from %d to %d due to DISTINCT\n",
+                         pWInfo->nRowOut, pWInfo->nRowOut-30));
+      pWInfo->nRowOut -= 30;
+    }
+
+  }
+  assert( pWInfo->pTabList!=0 );
+  if( pWInfo->pOrderBy==0 && (db->flags & SQLITE_ReverseOrder)!=0 ){
+    whereReverseScanOrder(pWInfo);
+  }
+  if( pParse->nErr ){
+    goto whereBeginError;
+  }
+  assert( db->mallocFailed==0 );
+#ifdef WHERETRACE_ENABLED
+  if( sqlite3WhereTrace ){
+    sqlite3DebugPrintf("---- Solution cost=%d, nRow=%d",
+                       pWInfo->rTotalCost, pWInfo->nRowOut);
+    if( pWInfo->nOBSat>0 ){
+      sqlite3DebugPrintf(" ORDERBY=%d,0x%llx", pWInfo->nOBSat, pWInfo->revMask);
+    }
+    switch( pWInfo->eDistinct ){
+      case WHERE_DISTINCT_UNIQUE: {
+        sqlite3DebugPrintf("  DISTINCT=unique");
+        break;
+      }
+      case WHERE_DISTINCT_ORDERED: {
+        sqlite3DebugPrintf("  DISTINCT=ordered");
+        break;
+      }
+      case WHERE_DISTINCT_UNORDERED: {
+        sqlite3DebugPrintf("  DISTINCT=unordered");
+        break;
+      }
+    }
+    sqlite3DebugPrintf("\n");
+    for(ii=0; ii<pWInfo->nLevel; ii++){
+      sqlite3WhereLoopPrint(pWInfo->a[ii].pWLoop, sWLB.pWC);
+    }
+  }
+#endif
+
+  /* Attempt to omit tables from a join that do not affect the result.
+  ** See the comment on whereOmitNoopJoin() for further information.
+  **
+  ** This query optimization is factored out into a separate "no-inline"
+  ** procedure to keep the sqlite3WhereBegin() procedure from becoming
+  ** too large.  If sqlite3WhereBegin() becomes too large, that prevents
+  ** some C-compiler optimizers from in-lining the
+  ** sqlite3WhereCodeOneLoopStart() procedure, and it is important to
+  ** in-line sqlite3WhereCodeOneLoopStart() for performance reasons.
+  */
+  notReady = ~(Bitmask)0;
+  if( pWInfo->nLevel>=2       /* Must be a join, or this opt8n is pointless */
+   && pResultSet!=0           /* Condition (1) */
+   && 0==(wctrlFlags & (WHERE_AGG_DISTINCT|WHERE_KEEP_ALL_JOINS)) /* (1),(6) */
+   && OptimizationEnabled(db, SQLITE_OmitNoopJoin)                /* (7) */
+  ){
+    notReady = whereOmitNoopJoin(pWInfo, notReady);
+    nTabList = pWInfo->nLevel;
+    assert( nTabList>0 );
+  }
+
+  /* Check to see if there are any SEARCH loops that might benefit from
+  ** using a Bloom filter.
+  */
+  if( pWInfo->nLevel>=2
+   && OptimizationEnabled(db, SQLITE_BloomFilter)
+  ){
+    whereCheckIfBloomFilterIsUseful(pWInfo);
+  }
+
+#if defined(WHERETRACE_ENABLED)
+  if( sqlite3WhereTrace & 0x4000 ){ /* Display all terms of the WHERE clause */
+    sqlite3DebugPrintf("---- WHERE clause at end of analysis:\n");
+    sqlite3WhereClausePrint(sWLB.pWC);
+  }
+  WHERETRACE(0xffffffff,("*** Optimizer Finished ***\n"));
+#endif
+  pWInfo->pParse->nQueryLoop += pWInfo->nRowOut;
+
+  /* If the caller is an UPDATE or DELETE statement that is requesting
+  ** to use a one-pass algorithm, determine if this is appropriate.
+  **
+  ** A one-pass approach can be used if the caller has requested one
+  ** and either (a) the scan visits at most one row or (b) each
+  ** of the following are true:
+  **
+  **   * the caller has indicated that a one-pass approach can be used
+  **     with multiple rows (by setting WHERE_ONEPASS_MULTIROW), and
+  **   * the table is not a virtual table, and
+  **   * either the scan does not use the OR optimization or the caller
+  **     is a DELETE operation (WHERE_DUPLICATES_OK is only specified
+  **     for DELETE).
+  **
+  ** The last qualification is because an UPDATE statement uses
+  ** WhereInfo.aiCurOnePass[1] to determine whether or not it really can
+  ** use a one-pass approach, and this is not set accurately for scans
+  ** that use the OR optimization.
+  */
+  assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
+  if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 ){
+    int wsFlags = pWInfo->a[0].pWLoop->wsFlags;
+    int bOnerow = (wsFlags & WHERE_ONEROW)!=0;
+    assert( !(wsFlags&WHERE_VIRTUALTABLE) || IsVirtual(pTabList->a[0].pSTab) );
+    if( bOnerow || (
+        0!=(wctrlFlags & WHERE_ONEPASS_MULTIROW)
+     && !IsVirtual(pTabList->a[0].pSTab)
+     && (0==(wsFlags & WHERE_MULTI_OR) || (wctrlFlags & WHERE_DUPLICATES_OK))
+     && OptimizationEnabled(db, SQLITE_OnePass)
+    )){
+      pWInfo->eOnePass = bOnerow ? ONEPASS_SINGLE : ONEPASS_MULTI;
+      if( HasRowid(pTabList->a[0].pSTab) && (wsFlags & WHERE_IDX_ONLY) ){
+        if( wctrlFlags & WHERE_ONEPASS_MULTIROW ){
+          bFordelete = OPFLAG_FORDELETE;
+        }
+        pWInfo->a[0].pWLoop->wsFlags = (wsFlags & ~WHERE_IDX_ONLY);
+      }
+    }
+  }
+
+  /* Open all tables in the pTabList and any indices selected for
+  ** searching those tables.
+  */
+  for(ii=0, pLevel=pWInfo->a; ii<nTabList; ii++, pLevel++){
+    Table *pTab;     /* Table to open */
+    int iDb;         /* Index of database containing table/index */
+    SrcItem *pTabItem;
+
+    pTabItem = &pTabList->a[pLevel->iFrom];
+    pTab = pTabItem->pSTab;
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    pLoop = pLevel->pWLoop;
+    if( (pTab->tabFlags & TF_Ephemeral)!=0 || IsView(pTab) ){
+      /* Do nothing */
+    }else
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
+      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
+      int iCur = pTabItem->iCursor;
+      sqlite3VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB);
+    }else if( IsVirtual(pTab) ){
+      /* noop */
+    }else
+#endif
+    if( ((pLoop->wsFlags & WHERE_IDX_ONLY)==0
+         && (wctrlFlags & WHERE_OR_SUBCLAUSE)==0)
+     || (pTabItem->fg.jointype & (JT_LTORJ|JT_RIGHT))!=0
+    ){
+      int op = OP_OpenRead;
+      if( pWInfo->eOnePass!=ONEPASS_OFF ){
+        op = OP_OpenWrite;
+        pWInfo->aiCurOnePass[0] = pTabItem->iCursor;
+      };
+      sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op);
+      assert( pTabItem->iCursor==pLevel->iTabCur );
+      testcase( pWInfo->eOnePass==ONEPASS_OFF && pTab->nCol==BMS-1 );
+      testcase( pWInfo->eOnePass==ONEPASS_OFF && pTab->nCol==BMS );
+      if( pWInfo->eOnePass==ONEPASS_OFF
+       && pTab->nCol<BMS
+       && (pTab->tabFlags & (TF_HasGenerated|TF_WithoutRowid))==0
+       && (pLoop->wsFlags & (WHERE_AUTO_INDEX|WHERE_BLOOMFILTER))==0
+      ){
+        /* If we know that only a prefix of the record will be used,
+        ** it is advantageous to reduce the "column count" field in
+        ** the P4 operand of the OP_OpenRead/Write opcode. */
+        Bitmask b = pTabItem->colUsed;
+        int n = 0;
+        for(; b; b=b>>1, n++){}
+        sqlite3VdbeChangeP4(v, -1, SQLITE_INT_TO_PTR(n), P4_INT32);
+        assert( n<=pTab->nCol );
+      }
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+      if( pLoop->u.btree.pIndex!=0 && (pTab->tabFlags & TF_WithoutRowid)==0 ){
+        sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ|bFordelete);
+      }else
+#endif
+      {
+        sqlite3VdbeChangeP5(v, bFordelete);
+      }
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+      sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, pTabItem->iCursor, 0, 0,
+                            (const u8*)&pTabItem->colUsed, P4_INT64);
+#endif
+    }else{
+      sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+    }
+    if( pLoop->wsFlags & WHERE_INDEXED ){
+      Index *pIx = pLoop->u.btree.pIndex;
+      int iIndexCur;
+      int op = OP_OpenRead;
+      /* iAuxArg is always set to a positive value if ONEPASS is possible */
+      assert( iAuxArg!=0 || (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 );
+      if( !HasRowid(pTab) && IsPrimaryKeyIndex(pIx)
+       && (wctrlFlags & WHERE_OR_SUBCLAUSE)!=0
+      ){
+        /* This is one term of an OR-optimization using the PRIMARY KEY of a
+        ** WITHOUT ROWID table.  No need for a separate index */
+        iIndexCur = pLevel->iTabCur;
+        op = 0;
+      }else if( pWInfo->eOnePass!=ONEPASS_OFF ){
+        Index *pJ = pTabItem->pSTab->pIndex;
+        iIndexCur = iAuxArg;
+        assert( wctrlFlags & WHERE_ONEPASS_DESIRED );
+        while( ALWAYS(pJ) && pJ!=pIx ){
+          iIndexCur++;
+          pJ = pJ->pNext;
+        }
+        op = OP_OpenWrite;
+        pWInfo->aiCurOnePass[1] = iIndexCur;
+      }else if( iAuxArg && (wctrlFlags & WHERE_OR_SUBCLAUSE)!=0 ){
+        iIndexCur = iAuxArg;
+        op = OP_ReopenIdx;
+      }else{
+        iIndexCur = pParse->nTab++;
+        if( pIx->bHasExpr && OptimizationEnabled(db, SQLITE_IndexedExpr) ){
+          whereAddIndexedExpr(pParse, pIx, iIndexCur, pTabItem);
+        }
+        if( pIx->pPartIdxWhere && (pTabItem->fg.jointype & JT_RIGHT)==0 ){
+          wherePartIdxExpr(
+              pParse, pIx, pIx->pPartIdxWhere, 0, iIndexCur, pTabItem
+          );
+        }
+      }
+      pLevel->iIdxCur = iIndexCur;
+      assert( pIx!=0 );
+      assert( pIx->pSchema==pTab->pSchema );
+      assert( iIndexCur>=0 );
+      if( op ){
+        sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb);
+        sqlite3VdbeSetP4KeyInfo(pParse, pIx);
+        if( (pLoop->wsFlags & WHERE_CONSTRAINT)!=0
+         && (pLoop->wsFlags & (WHERE_COLUMN_RANGE|WHERE_SKIPSCAN))==0
+         && (pLoop->wsFlags & WHERE_BIGNULL_SORT)==0
+         && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0
+         && (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0
+         && pWInfo->eDistinct!=WHERE_DISTINCT_ORDERED
+        ){
+          sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ);
+        }
+        VdbeComment((v, "%s", pIx->zName));
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+        {
+          u64 colUsed = 0;
+          int ii, jj;
+          for(ii=0; ii<pIx->nColumn; ii++){
+            jj = pIx->aiColumn[ii];
+            if( jj<0 ) continue;
+            if( jj>63 ) jj = 63;
+            if( (pTabItem->colUsed & MASKBIT(jj))==0 ) continue;
+            colUsed |= ((u64)1)<<(ii<63 ? ii : 63);
+          }
+          sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, iIndexCur, 0, 0,
+                                (u8*)&colUsed, P4_INT64);
+        }
+#endif /* SQLITE_ENABLE_COLUMN_USED_MASK */
+      }
+    }
+    if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);
+    if( (pTabItem->fg.jointype & JT_RIGHT)!=0
+     && (pLevel->pRJ = sqlite3WhereMalloc(pWInfo, sizeof(WhereRightJoin)))!=0
+    ){
+      WhereRightJoin *pRJ = pLevel->pRJ;
+      pRJ->iMatch = pParse->nTab++;
+      pRJ->regBloom = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Blob, 65536, pRJ->regBloom);
+      pRJ->regReturn = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, pRJ->regReturn);
+      assert( pTab==pTabItem->pSTab );
+      if( HasRowid(pTab) ){
+        KeyInfo *pInfo;
+        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRJ->iMatch, 1);
+        pInfo = sqlite3KeyInfoAlloc(pParse->db, 1, 0);
+        if( pInfo ){
+          pInfo->aColl[0] = 0;
+          pInfo->aSortFlags[0] = 0;
+          sqlite3VdbeAppendP4(v, pInfo, P4_KEYINFO);
+        }
+      }else{
+        Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRJ->iMatch, pPk->nKeyCol);
+        sqlite3VdbeSetP4KeyInfo(pParse, pPk);
+      }
+      pLoop->wsFlags &= ~WHERE_IDX_ONLY;
+      /* The nature of RIGHT JOIN processing is such that it messes up
+      ** the output order.  So omit any ORDER BY/GROUP BY elimination
+      ** optimizations.  We need to do an actual sort for RIGHT JOIN. */
+      pWInfo->nOBSat = 0;
+      pWInfo->eDistinct = WHERE_DISTINCT_UNORDERED;
+    }
+  }
+  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
+  if( db->mallocFailed ) goto whereBeginError;
+
+  /* Generate the code to do the search.  Each iteration of the for
+  ** loop below generates code for a single nested loop of the VM
+  ** program.
+  */
+  for(ii=0; ii<nTabList; ii++){
+    int addrExplain;
+    int wsFlags;
+    SrcItem *pSrc;
+    if( pParse->nErr ) goto whereBeginError;
+    pLevel = &pWInfo->a[ii];
+    wsFlags = pLevel->pWLoop->wsFlags;
+    pSrc = &pTabList->a[pLevel->iFrom];
+    if( pSrc->fg.isMaterialized ){
+      Subquery *pSubq;
+      int iOnce = 0;
+      assert( pSrc->fg.isSubquery );
+      pSubq = pSrc->u4.pSubq;
+      if( pSrc->fg.isCorrelated==0 ){
+        iOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+      }else{
+        iOnce = 0;
+      }
+      sqlite3VdbeAddOp2(v, OP_Gosub, pSubq->regReturn, pSubq->addrFillSub);
+      VdbeComment((v, "materialize %!S", pSrc));
+      if( iOnce )  sqlite3VdbeJumpHere(v, iOnce);
+    }
+    assert( pTabList == pWInfo->pTabList );
+    if( (wsFlags & (WHERE_AUTO_INDEX|WHERE_BLOOMFILTER))!=0 ){
+      if( (wsFlags & WHERE_AUTO_INDEX)!=0 ){
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+        constructAutomaticIndex(pParse, &pWInfo->sWC, notReady, pLevel);
+#endif
+      }else{
+        sqlite3ConstructBloomFilter(pWInfo, ii, pLevel, notReady);
+      }
+      if( db->mallocFailed ) goto whereBeginError;
+    }
+    addrExplain = sqlite3WhereExplainOneScan(
+        pParse, pTabList, pLevel, wctrlFlags
+    );
+    pLevel->addrBody = sqlite3VdbeCurrentAddr(v);
+    notReady = sqlite3WhereCodeOneLoopStart(pParse,v,pWInfo,ii,pLevel,notReady);
+    pWInfo->iContinue = pLevel->addrCont;
+    if( (wsFlags&WHERE_MULTI_OR)==0 && (wctrlFlags&WHERE_OR_SUBCLAUSE)==0 ){
+      sqlite3WhereAddScanStatus(v, pTabList, pLevel, addrExplain);
+    }
+  }
+
+  /* Done. */
+  VdbeModuleComment((v, "Begin WHERE-core"));
+  pWInfo->iEndWhere = sqlite3VdbeCurrentAddr(v);
+  return pWInfo;
+
+  /* Jump here if malloc fails */
+whereBeginError:
+  if( pWInfo ){
+    pParse->nQueryLoop = pWInfo->savedNQueryLoop;
+    whereInfoFree(db, pWInfo);
+  }
+#ifdef WHERETRACE_ENABLED
+  /* Prevent harmless compiler warnings about debugging routines
+  ** being declared but never used */
+  sqlite3ShowWhereLoopList(0);
+#endif /* WHERETRACE_ENABLED */
+  return 0;
+}
+
+/*
+** Part of sqlite3WhereEnd() will rewrite opcodes to reference the
+** index rather than the main table.  In SQLITE_DEBUG mode, we want
+** to trace those changes if PRAGMA vdbe_addoptrace=on.  This routine
+** does that.
+*/
+#ifndef SQLITE_DEBUG
+# define OpcodeRewriteTrace(D,K,P) /* no-op */
+#else
+# define OpcodeRewriteTrace(D,K,P) sqlite3WhereOpcodeRewriteTrace(D,K,P)
+  static void sqlite3WhereOpcodeRewriteTrace(
+    sqlite3 *db,
+    int pc,
+    VdbeOp *pOp
+  ){
+    if( (db->flags & SQLITE_VdbeAddopTrace)==0 ) return;
+    sqlite3VdbePrintOp(0, pc, pOp);
+    sqlite3ShowWhereTerm(0); /* So compiler won't complain about unused func */
+  }
+#endif
+
+/*
+** Generate the end of the WHERE loop.  See comments on
+** sqlite3WhereBegin() for additional information.
+*/
+SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
+  Parse *pParse = pWInfo->pParse;
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  WhereLevel *pLevel;
+  WhereLoop *pLoop;
+  SrcList *pTabList = pWInfo->pTabList;
+  sqlite3 *db = pParse->db;
+  int iEnd = sqlite3VdbeCurrentAddr(v);
+  int nRJ = 0;
+
+  /* Generate loop termination code.
+  */
+  VdbeModuleComment((v, "End WHERE-core"));
+  for(i=pWInfo->nLevel-1; i>=0; i--){
+    int addr;
+    pLevel = &pWInfo->a[i];
+    if( pLevel->pRJ ){
+      /* Terminate the subroutine that forms the interior of the loop of
+      ** the RIGHT JOIN table */
+      WhereRightJoin *pRJ = pLevel->pRJ;
+      sqlite3VdbeResolveLabel(v, pLevel->addrCont);
+      pLevel->addrCont = 0;
+      pRJ->endSubrtn = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp3(v, OP_Return, pRJ->regReturn, pRJ->addrSubrtn, 1);
+      VdbeCoverage(v);
+      nRJ++;
+    }
+    pLoop = pLevel->pWLoop;
+    if( pLevel->op!=OP_Noop ){
+#ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT
+      int addrSeek = 0;
+      Index *pIdx;
+      int n;
+      if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED
+       && i==pWInfo->nLevel-1  /* Ticket [ef9318757b152e3] 2017-10-21 */
+       && (pLoop->wsFlags & WHERE_INDEXED)!=0
+       && (pIdx = pLoop->u.btree.pIndex)->hasStat1
+       && (n = pLoop->u.btree.nDistinctCol)>0
+       && pIdx->aiRowLogEst[n]>=36
+      ){
+        int r1 = pParse->nMem+1;
+        int j, op;
+        for(j=0; j<n; j++){
+          sqlite3VdbeAddOp3(v, OP_Column, pLevel->iIdxCur, j, r1+j);
+        }
+        pParse->nMem += n+1;
+        op = pLevel->op==OP_Prev ? OP_SeekLT : OP_SeekGT;
+        addrSeek = sqlite3VdbeAddOp4Int(v, op, pLevel->iIdxCur, 0, r1, n);
+        VdbeCoverageIf(v, op==OP_SeekLT);
+        VdbeCoverageIf(v, op==OP_SeekGT);
+        sqlite3VdbeAddOp2(v, OP_Goto, 1, pLevel->p2);
+      }
+#endif /* SQLITE_DISABLE_SKIPAHEAD_DISTINCT */
+      /* The common case: Advance to the next row */
+      if( pLevel->addrCont ) sqlite3VdbeResolveLabel(v, pLevel->addrCont);
+      sqlite3VdbeAddOp3(v, pLevel->op, pLevel->p1, pLevel->p2, pLevel->p3);
+      sqlite3VdbeChangeP5(v, pLevel->p5);
+      VdbeCoverage(v);
+      VdbeCoverageIf(v, pLevel->op==OP_Next);
+      VdbeCoverageIf(v, pLevel->op==OP_Prev);
+      VdbeCoverageIf(v, pLevel->op==OP_VNext);
+      if( pLevel->regBignull ){
+        sqlite3VdbeResolveLabel(v, pLevel->addrBignull);
+        sqlite3VdbeAddOp2(v, OP_DecrJumpZero, pLevel->regBignull, pLevel->p2-1);
+        VdbeCoverage(v);
+      }
+#ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT
+      if( addrSeek ) sqlite3VdbeJumpHere(v, addrSeek);
+#endif
+    }else if( pLevel->addrCont ){
+      sqlite3VdbeResolveLabel(v, pLevel->addrCont);
+    }
+    if( (pLoop->wsFlags & WHERE_IN_ABLE)!=0 && pLevel->u.in.nIn>0 ){
+      struct InLoop *pIn;
+      int j;
+      sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
+      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
+        assert( sqlite3VdbeGetOp(v, pIn->addrInTop+1)->opcode==OP_IsNull
+                 || pParse->db->mallocFailed );
+        sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
+        if( pIn->eEndLoopOp!=OP_Noop ){
+          if( pIn->nPrefix ){
+            int bEarlyOut =
+                (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0
+                 && (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0;
+            if( pLevel->iLeftJoin ){
+              /* For LEFT JOIN queries, cursor pIn->iCur may not have been
+              ** opened yet. This occurs for WHERE clauses such as
+              ** "a = ? AND b IN (...)", where the index is on (a, b). If
+              ** the RHS of the (a=?) is NULL, then the "b IN (...)" may
+              ** never have been coded, but the body of the loop run to
+              ** return the null-row. So, if the cursor is not open yet,
+              ** jump over the OP_Next or OP_Prev instruction about to
+              ** be coded.  */
+              sqlite3VdbeAddOp2(v, OP_IfNotOpen, pIn->iCur,
+                  sqlite3VdbeCurrentAddr(v) + 2 + bEarlyOut);
+              VdbeCoverage(v);
+            }
+            if( bEarlyOut ){
+              sqlite3VdbeAddOp4Int(v, OP_IfNoHope, pLevel->iIdxCur,
+                  sqlite3VdbeCurrentAddr(v)+2,
+                  pIn->iBase, pIn->nPrefix);
+              VdbeCoverage(v);
+              /* Retarget the OP_IsNull against the left operand of IN so
+              ** it jumps past the OP_IfNoHope.  This is because the
+              ** OP_IsNull also bypasses the OP_Affinity opcode that is
+              ** required by OP_IfNoHope. */
+              sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
+            }
+          }
+          sqlite3VdbeAddOp2(v, pIn->eEndLoopOp, pIn->iCur, pIn->addrInTop);
+          VdbeCoverage(v);
+          VdbeCoverageIf(v, pIn->eEndLoopOp==OP_Prev);
+          VdbeCoverageIf(v, pIn->eEndLoopOp==OP_Next);
+        }
+        sqlite3VdbeJumpHere(v, pIn->addrInTop-1);
+      }
+    }
+    sqlite3VdbeResolveLabel(v, pLevel->addrBrk);
+    if( pLevel->pRJ ){
+      sqlite3VdbeAddOp3(v, OP_Return, pLevel->pRJ->regReturn, 0, 1);
+      VdbeCoverage(v);
+    }
+    if( pLevel->addrSkip ){
+      sqlite3VdbeGoto(v, pLevel->addrSkip);
+      VdbeComment((v, "next skip-scan on %s", pLoop->u.btree.pIndex->zName));
+      sqlite3VdbeJumpHere(v, pLevel->addrSkip);
+      sqlite3VdbeJumpHere(v, pLevel->addrSkip-2);
+    }
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+    if( pLevel->addrLikeRep ){
+      sqlite3VdbeAddOp2(v, OP_DecrJumpZero, (int)(pLevel->iLikeRepCntr>>1),
+                        pLevel->addrLikeRep);
+      VdbeCoverage(v);
+    }
+#endif
+    if( pLevel->iLeftJoin ){
+      int ws = pLoop->wsFlags;
+      addr = sqlite3VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin); VdbeCoverage(v);
+      assert( (ws & WHERE_IDX_ONLY)==0 || (ws & WHERE_INDEXED)!=0 );
+      if( (ws & WHERE_IDX_ONLY)==0 ){
+        SrcItem *pSrc = &pTabList->a[pLevel->iFrom];
+        assert( pLevel->iTabCur==pSrc->iCursor );
+        if( pSrc->fg.viaCoroutine ){
+          int m, n;
+          assert( pSrc->fg.isSubquery );
+          n = pSrc->u4.pSubq->regResult;
+          assert( pSrc->pSTab!=0 );
+          m = pSrc->pSTab->nCol;
+          sqlite3VdbeAddOp3(v, OP_Null, 0, n, n+m-1);
+        }
+        sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iTabCur);
+      }
+      if( (ws & WHERE_INDEXED)
+       || ((ws & WHERE_MULTI_OR) && pLevel->u.pCoveringIdx)
+      ){
+        if( ws & WHERE_MULTI_OR ){
+          Index *pIx = pLevel->u.pCoveringIdx;
+          int iDb = sqlite3SchemaToIndex(db, pIx->pSchema);
+          sqlite3VdbeAddOp3(v, OP_ReopenIdx, pLevel->iIdxCur, pIx->tnum, iDb);
+          sqlite3VdbeSetP4KeyInfo(pParse, pIx);
+        }
+        sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
+      }
+      if( pLevel->op==OP_Return ){
+        sqlite3VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
+      }else{
+        sqlite3VdbeGoto(v, pLevel->addrFirst);
+      }
+      sqlite3VdbeJumpHere(v, addr);
+    }
+    VdbeModuleComment((v, "End WHERE-loop%d: %s", i,
+                     pWInfo->pTabList->a[pLevel->iFrom].pSTab->zName));
+  }
+
+  assert( pWInfo->nLevel<=pTabList->nSrc );
+  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
+    int k, last;
+    VdbeOp *pOp, *pLastOp;
+    Index *pIdx = 0;
+    SrcItem *pTabItem = &pTabList->a[pLevel->iFrom];
+    Table *pTab = pTabItem->pSTab;
+    assert( pTab!=0 );
+    pLoop = pLevel->pWLoop;
+
+    /* Do RIGHT JOIN processing.  Generate code that will output the
+    ** unmatched rows of the right operand of the RIGHT JOIN with
+    ** all of the columns of the left operand set to NULL.
+    */
+    if( pLevel->pRJ ){
+      sqlite3WhereRightJoinLoop(pWInfo, i, pLevel);
+      continue;
+    }
+
+    /* For a co-routine, change all OP_Column references to the table of
+    ** the co-routine into OP_Copy of result contained in a register.
+    ** OP_Rowid becomes OP_Null.
+    */
+    if( pTabItem->fg.viaCoroutine ){
+      testcase( pParse->db->mallocFailed );
+      assert( pTabItem->fg.isSubquery );
+      assert( pTabItem->u4.pSubq->regResult>=0 );
+      translateColumnToCopy(pParse, pLevel->addrBody, pLevel->iTabCur,
+                            pTabItem->u4.pSubq->regResult, 0);
+      continue;
+    }
+
+    /* If this scan uses an index, make VDBE code substitutions to read data
+    ** from the index instead of from the table where possible.  In some cases
+    ** this optimization prevents the table from ever being read, which can
+    ** yield a significant performance boost.
+    **
+    ** Calls to the code generator in between sqlite3WhereBegin and
+    ** sqlite3WhereEnd will have created code that references the table
+    ** directly.  This loop scans all that code looking for opcodes
+    ** that reference the table and converts them into opcodes that
+    ** reference the index.
+    */
+    if( pLoop->wsFlags & (WHERE_INDEXED|WHERE_IDX_ONLY) ){
+      pIdx = pLoop->u.btree.pIndex;
+    }else if( pLoop->wsFlags & WHERE_MULTI_OR ){
+      pIdx = pLevel->u.pCoveringIdx;
+    }
+    if( pIdx
+     && !db->mallocFailed
+    ){
+      if( pWInfo->eOnePass==ONEPASS_OFF || !HasRowid(pIdx->pTable) ){
+        last = iEnd;
+      }else{
+        last = pWInfo->iEndWhere;
+      }
+      if( pIdx->bHasExpr ){
+        IndexedExpr *p = pParse->pIdxEpr;
+        while( p ){
+          if( p->iIdxCur==pLevel->iIdxCur ){
+#ifdef WHERETRACE_ENABLED
+            if( sqlite3WhereTrace & 0x200 ){
+              sqlite3DebugPrintf("Disable pParse->pIdxEpr term {%d,%d}\n",
+                                  p->iIdxCur, p->iIdxCol);
+              if( sqlite3WhereTrace & 0x5000 ) sqlite3ShowExpr(p->pExpr);
+            }
+#endif
+            p->iDataCur = -1;
+            p->iIdxCur = -1;
+          }
+          p = p->pIENext;
+        }
+      }
+      k = pLevel->addrBody + 1;
+#ifdef SQLITE_DEBUG
+      if( db->flags & SQLITE_VdbeAddopTrace ){
+        printf("TRANSLATE cursor %d->%d in opcode range %d..%d\n",
+                pLevel->iTabCur, pLevel->iIdxCur, k, last-1);
+      }
+      /* Proof that the "+1" on the k value above is safe */
+      pOp = sqlite3VdbeGetOp(v, k - 1);
+      assert( pOp->opcode!=OP_Column || pOp->p1!=pLevel->iTabCur );
+      assert( pOp->opcode!=OP_Rowid  || pOp->p1!=pLevel->iTabCur );
+      assert( pOp->opcode!=OP_IfNullRow || pOp->p1!=pLevel->iTabCur );
+#endif
+      pOp = sqlite3VdbeGetOp(v, k);
+      pLastOp = pOp + (last - k);
+      assert( pOp<=pLastOp );
+      do{
+        if( pOp->p1!=pLevel->iTabCur ){
+          /* no-op */
+        }else if( pOp->opcode==OP_Column
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+         || pOp->opcode==OP_Offset
+#endif
+        ){
+          int x = pOp->p2;
+          assert( pIdx->pTable==pTab );
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+          if( pOp->opcode==OP_Offset ){
+            /* Do not need to translate the column number */
+          }else
+#endif
+          if( !HasRowid(pTab) ){
+            Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+            x = pPk->aiColumn[x];
+            assert( x>=0 );
+          }else{
+            testcase( x!=sqlite3StorageColumnToTable(pTab,x) );
+            x = sqlite3StorageColumnToTable(pTab,x);
+          }
+          x = sqlite3TableColumnToIndex(pIdx, x);
+          if( x>=0 ){
+            pOp->p2 = x;
+            pOp->p1 = pLevel->iIdxCur;
+            OpcodeRewriteTrace(db, k, pOp);
+          }else if( pLoop->wsFlags & (WHERE_IDX_ONLY|WHERE_EXPRIDX) ){
+            if( pLoop->wsFlags & WHERE_IDX_ONLY ){
+              /* An error. pLoop is supposed to be a covering index loop,
+              ** and yet the VM code refers to a column of the table that
+              ** is not part of the index.  */
+              sqlite3ErrorMsg(pParse, "internal query planner error");
+              pParse->rc = SQLITE_INTERNAL;
+            }else{
+              /* The WHERE_EXPRIDX flag is set by the planner when it is likely
+              ** that pLoop is a covering index loop, but it is not possible
+              ** to be 100% sure. In this case, any OP_Explain opcode
+              ** corresponding to this loop describes the index as a "COVERING
+              ** INDEX". But, pOp proves that pLoop is not actually a covering
+              ** index loop. So clear the WHERE_EXPRIDX flag and rewrite the
+              ** text that accompanies the OP_Explain opcode, if any.  */
+              pLoop->wsFlags &= ~WHERE_EXPRIDX;
+              sqlite3WhereAddExplainText(pParse,
+                  pLevel->addrBody-1,
+                  pTabList,
+                  pLevel,
+                  pWInfo->wctrlFlags
+              );
+            }
+          }
+        }else if( pOp->opcode==OP_Rowid ){
+          pOp->p1 = pLevel->iIdxCur;
+          pOp->opcode = OP_IdxRowid;
+          OpcodeRewriteTrace(db, k, pOp);
+        }else if( pOp->opcode==OP_IfNullRow ){
+          pOp->p1 = pLevel->iIdxCur;
+          OpcodeRewriteTrace(db, k, pOp);
+        }
+#ifdef SQLITE_DEBUG
+        k++;
+#endif
+      }while( (++pOp)<pLastOp );
+#ifdef SQLITE_DEBUG
+      if( db->flags & SQLITE_VdbeAddopTrace ) printf("TRANSLATE complete\n");
+#endif
+    }
+  }
+
+  /* The "break" point is here, just past the end of the outer loop.
+  ** Set it.
+  */
+  sqlite3VdbeResolveLabel(v, pWInfo->iBreak);
+
+  /* Final cleanup
+  */
+  pParse->nQueryLoop = pWInfo->savedNQueryLoop;
+  whereInfoFree(db, pWInfo);
+  pParse->withinRJSubrtn -= nRJ;
+  return;
+}
+
+/************** End of where.c ***********************************************/
+/************** Begin file window.c ******************************************/
+/*
+** 2018 May 08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+
+/*
+** SELECT REWRITING
+**
+**   Any SELECT statement that contains one or more window functions in
+**   either the select list or ORDER BY clause (the only two places window
+**   functions may be used) is transformed by function sqlite3WindowRewrite()
+**   in order to support window function processing. For example, with the
+**   schema:
+**
+**     CREATE TABLE t1(a, b, c, d, e, f, g);
+**
+**   the statement:
+**
+**     SELECT a+1, max(b) OVER (PARTITION BY c ORDER BY d) FROM t1 ORDER BY e;
+**
+**   is transformed to:
+**
+**     SELECT a+1, max(b) OVER (PARTITION BY c ORDER BY d) FROM (
+**         SELECT a, e, c, d, b FROM t1 ORDER BY c, d
+**     ) ORDER BY e;
+**
+**   The flattening optimization is disabled when processing this transformed
+**   SELECT statement. This allows the implementation of the window function
+**   (in this case max()) to process rows sorted in order of (c, d), which
+**   makes things easier for obvious reasons. More generally:
+**
+**     * FROM, WHERE, GROUP BY and HAVING clauses are all moved to
+**       the sub-query.
+**
+**     * ORDER BY, LIMIT and OFFSET remain part of the parent query.
+**
+**     * Terminals from each of the expression trees that make up the
+**       select-list and ORDER BY expressions in the parent query are
+**       selected by the sub-query. For the purposes of the transformation,
+**       terminals are column references and aggregate functions.
+**
+**   If there is more than one window function in the SELECT that uses
+**   the same window declaration (the OVER bit), then a single scan may
+**   be used to process more than one window function. For example:
+**
+**     SELECT max(b) OVER (PARTITION BY c ORDER BY d),
+**            min(e) OVER (PARTITION BY c ORDER BY d)
+**     FROM t1;
+**
+**   is transformed in the same way as the example above. However:
+**
+**     SELECT max(b) OVER (PARTITION BY c ORDER BY d),
+**            min(e) OVER (PARTITION BY a ORDER BY b)
+**     FROM t1;
+**
+**   Must be transformed to:
+**
+**     SELECT max(b) OVER (PARTITION BY c ORDER BY d) FROM (
+**         SELECT e, min(e) OVER (PARTITION BY a ORDER BY b), c, d, b FROM
+**           SELECT a, e, c, d, b FROM t1 ORDER BY a, b
+**         ) ORDER BY c, d
+**     ) ORDER BY e;
+**
+**   so that both min() and max() may process rows in the order defined by
+**   their respective window declarations.
+**
+** INTERFACE WITH SELECT.C
+**
+**   When processing the rewritten SELECT statement, code in select.c calls
+**   sqlite3WhereBegin() to begin iterating through the results of the
+**   sub-query, which is always implemented as a co-routine. It then calls
+**   sqlite3WindowCodeStep() to process rows and finish the scan by calling
+**   sqlite3WhereEnd().
+**
+**   sqlite3WindowCodeStep() generates VM code so that, for each row returned
+**   by the sub-query a sub-routine (OP_Gosub) coded by select.c is invoked.
+**   When the sub-routine is invoked:
+**
+**     * The results of all window-functions for the row are stored
+**       in the associated Window.regResult registers.
+**
+**     * The required terminal values are stored in the current row of
+**       temp table Window.iEphCsr.
+**
+**   In some cases, depending on the window frame and the specific window
+**   functions invoked, sqlite3WindowCodeStep() caches each entire partition
+**   in a temp table before returning any rows. In other cases it does not.
+**   This detail is encapsulated within this file, the code generated by
+**   select.c is the same in either case.
+**
+** BUILT-IN WINDOW FUNCTIONS
+**
+**   This implementation features the following built-in window functions:
+**
+**     row_number()
+**     rank()
+**     dense_rank()
+**     percent_rank()
+**     cume_dist()
+**     ntile(N)
+**     lead(expr [, offset [, default]])
+**     lag(expr [, offset [, default]])
+**     first_value(expr)
+**     last_value(expr)
+**     nth_value(expr, N)
+**
+**   These are the same built-in window functions supported by Postgres.
+**   Although the behaviour of aggregate window functions (functions that
+**   can be used as either aggregates or window functions) allows them to
+**   be implemented using an API, built-in window functions are much more
+**   esoteric. Additionally, some window functions (e.g. nth_value())
+**   may only be implemented by caching the entire partition in memory.
+**   As such, some built-in window functions use the same API as aggregate
+**   window functions and some are implemented directly using VDBE
+**   instructions. Additionally, for those functions that use the API, the
+**   window frame is sometimes modified before the SELECT statement is
+**   rewritten. For example, regardless of the specified window frame, the
+**   row_number() function always uses:
+**
+**     ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+**
+**   See sqlite3WindowUpdate() for details.
+**
+**   As well as some of the built-in window functions, aggregate window
+**   functions min() and max() are implemented using VDBE instructions if
+**   the start of the window frame is declared as anything other than
+**   UNBOUNDED PRECEDING.
+*/
+
+/*
+** Implementation of built-in window function row_number(). Assumes that the
+** window frame has been coerced to:
+**
+**   ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+*/
+static void row_numberStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  i64 *p = (i64*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ) (*p)++;
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+}
+static void row_numberValueFunc(sqlite3_context *pCtx){
+  i64 *p = (i64*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  sqlite3_result_int64(pCtx, (p ? *p : 0));
+}
+
+/*
+** Context object type used by rank(), dense_rank(), percent_rank() and
+** cume_dist().
+*/
+struct CallCount {
+  i64 nValue;
+  i64 nStep;
+  i64 nTotal;
+};
+
+/*
+** Implementation of built-in window function dense_rank(). Assumes that
+** the window frame has been set to:
+**
+**   RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+*/
+static void dense_rankStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ) p->nStep = 1;
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+}
+static void dense_rankValueFunc(sqlite3_context *pCtx){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    if( p->nStep ){
+      p->nValue++;
+      p->nStep = 0;
+    }
+    sqlite3_result_int64(pCtx, p->nValue);
+  }
+}
+
+/*
+** Implementation of built-in window function nth_value(). This
+** implementation is used in "slow mode" only - when the EXCLUDE clause
+** is not set to the default value "NO OTHERS".
+*/
+struct NthValueCtx {
+  i64 nStep;
+  sqlite3_value *pValue;
+};
+static void nth_valueStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct NthValueCtx *p;
+  p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    i64 iVal;
+    switch( sqlite3_value_numeric_type(apArg[1]) ){
+      case SQLITE_INTEGER:
+        iVal = sqlite3_value_int64(apArg[1]);
+        break;
+      case SQLITE_FLOAT: {
+        double fVal = sqlite3_value_double(apArg[1]);
+        if( ((i64)fVal)!=fVal ) goto error_out;
+        iVal = (i64)fVal;
+        break;
+      }
+      default:
+        goto error_out;
+    }
+    if( iVal<=0 ) goto error_out;
+
+    p->nStep++;
+    if( iVal==p->nStep ){
+      p->pValue = sqlite3_value_dup(apArg[0]);
+      if( !p->pValue ){
+        sqlite3_result_error_nomem(pCtx);
+      }
+    }
+  }
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+  return;
+
+ error_out:
+  sqlite3_result_error(
+      pCtx, "second argument to nth_value must be a positive integer", -1
+  );
+}
+static void nth_valueFinalizeFunc(sqlite3_context *pCtx){
+  struct NthValueCtx *p;
+  p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, 0);
+  if( p && p->pValue ){
+    sqlite3_result_value(pCtx, p->pValue);
+    sqlite3_value_free(p->pValue);
+    p->pValue = 0;
+  }
+}
+#define nth_valueInvFunc noopStepFunc
+#define nth_valueValueFunc noopValueFunc
+
+static void first_valueStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct NthValueCtx *p;
+  p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p && p->pValue==0 ){
+    p->pValue = sqlite3_value_dup(apArg[0]);
+    if( !p->pValue ){
+      sqlite3_result_error_nomem(pCtx);
+    }
+  }
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+}
+static void first_valueFinalizeFunc(sqlite3_context *pCtx){
+  struct NthValueCtx *p;
+  p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p && p->pValue ){
+    sqlite3_result_value(pCtx, p->pValue);
+    sqlite3_value_free(p->pValue);
+    p->pValue = 0;
+  }
+}
+#define first_valueInvFunc noopStepFunc
+#define first_valueValueFunc noopValueFunc
+
+/*
+** Implementation of built-in window function rank(). Assumes that
+** the window frame has been set to:
+**
+**   RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+*/
+static void rankStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    p->nStep++;
+    if( p->nValue==0 ){
+      p->nValue = p->nStep;
+    }
+  }
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+}
+static void rankValueFunc(sqlite3_context *pCtx){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    sqlite3_result_int64(pCtx, p->nValue);
+    p->nValue = 0;
+  }
+}
+
+/*
+** Implementation of built-in window function percent_rank(). Assumes that
+** the window frame has been set to:
+**
+**   GROUPS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+*/
+static void percent_rankStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  UNUSED_PARAMETER(nArg); assert( nArg==0 );
+  UNUSED_PARAMETER(apArg);
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    p->nTotal++;
+  }
+}
+static void percent_rankInvFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  UNUSED_PARAMETER(nArg); assert( nArg==0 );
+  UNUSED_PARAMETER(apArg);
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  p->nStep++;
+}
+static void percent_rankValueFunc(sqlite3_context *pCtx){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    p->nValue = p->nStep;
+    if( p->nTotal>1 ){
+      double r = (double)p->nValue / (double)(p->nTotal-1);
+      sqlite3_result_double(pCtx, r);
+    }else{
+      sqlite3_result_double(pCtx, 0.0);
+    }
+  }
+}
+#define percent_rankFinalizeFunc percent_rankValueFunc
+
+/*
+** Implementation of built-in window function cume_dist(). Assumes that
+** the window frame has been set to:
+**
+**   GROUPS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING
+*/
+static void cume_distStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  UNUSED_PARAMETER(nArg); assert( nArg==0 );
+  UNUSED_PARAMETER(apArg);
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    p->nTotal++;
+  }
+}
+static void cume_distInvFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  UNUSED_PARAMETER(nArg); assert( nArg==0 );
+  UNUSED_PARAMETER(apArg);
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  p->nStep++;
+}
+static void cume_distValueFunc(sqlite3_context *pCtx){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, 0);
+  if( p ){
+    double r = (double)(p->nStep) / (double)(p->nTotal);
+    sqlite3_result_double(pCtx, r);
+  }
+}
+#define cume_distFinalizeFunc cume_distValueFunc
+
+/*
+** Context object for ntile() window function.
+*/
+struct NtileCtx {
+  i64 nTotal;                     /* Total rows in partition */
+  i64 nParam;                     /* Parameter passed to ntile(N) */
+  i64 iRow;                       /* Current row */
+};
+
+/*
+** Implementation of ntile(). This assumes that the window frame has
+** been coerced to:
+**
+**   ROWS CURRENT ROW AND UNBOUNDED FOLLOWING
+*/
+static void ntileStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct NtileCtx *p;
+  assert( nArg==1 ); UNUSED_PARAMETER(nArg);
+  p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    if( p->nTotal==0 ){
+      p->nParam = sqlite3_value_int64(apArg[0]);
+      if( p->nParam<=0 ){
+        sqlite3_result_error(
+            pCtx, "argument of ntile must be a positive integer", -1
+        );
+      }
+    }
+    p->nTotal++;
+  }
+}
+static void ntileInvFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct NtileCtx *p;
+  assert( nArg==1 ); UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+  p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  p->iRow++;
+}
+static void ntileValueFunc(sqlite3_context *pCtx){
+  struct NtileCtx *p;
+  p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p && p->nParam>0 ){
+    int nSize = (p->nTotal / p->nParam);
+    if( nSize==0 ){
+      sqlite3_result_int64(pCtx, p->iRow+1);
+    }else{
+      i64 nLarge = p->nTotal - p->nParam*nSize;
+      i64 iSmall = nLarge*(nSize+1);
+      i64 iRow = p->iRow;
+
+      assert( (nLarge*(nSize+1) + (p->nParam-nLarge)*nSize)==p->nTotal );
+
+      if( iRow<iSmall ){
+        sqlite3_result_int64(pCtx, 1 + iRow/(nSize+1));
+      }else{
+        sqlite3_result_int64(pCtx, 1 + nLarge + (iRow-iSmall)/nSize);
+      }
+    }
+  }
+}
+#define ntileFinalizeFunc ntileValueFunc
+
+/*
+** Context object for last_value() window function.
+*/
+struct LastValueCtx {
+  sqlite3_value *pVal;
+  int nVal;
+};
+
+/*
+** Implementation of last_value().
+*/
+static void last_valueStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct LastValueCtx *p;
+  UNUSED_PARAMETER(nArg);
+  p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    sqlite3_value_free(p->pVal);
+    p->pVal = sqlite3_value_dup(apArg[0]);
+    if( p->pVal==0 ){
+      sqlite3_result_error_nomem(pCtx);
+    }else{
+      p->nVal++;
+    }
+  }
+}
+static void last_valueInvFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct LastValueCtx *p;
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+  p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( ALWAYS(p) ){
+    p->nVal--;
+    if( p->nVal==0 ){
+      sqlite3_value_free(p->pVal);
+      p->pVal = 0;
+    }
+  }
+}
+static void last_valueValueFunc(sqlite3_context *pCtx){
+  struct LastValueCtx *p;
+  p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, 0);
+  if( p && p->pVal ){
+    sqlite3_result_value(pCtx, p->pVal);
+  }
+}
+static void last_valueFinalizeFunc(sqlite3_context *pCtx){
+  struct LastValueCtx *p;
+  p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p && p->pVal ){
+    sqlite3_result_value(pCtx, p->pVal);
+    sqlite3_value_free(p->pVal);
+    p->pVal = 0;
+  }
+}
+
+/*
+** Static names for the built-in window function names.  These static
+** names are used, rather than string literals, so that FuncDef objects
+** can be associated with a particular window function by direct
+** comparison of the zName pointer.  Example:
+**
+**       if( pFuncDef->zName==row_valueName ){ ... }
+*/
+static const char row_numberName[] =   "row_number";
+static const char dense_rankName[] =   "dense_rank";
+static const char rankName[] =         "rank";
+static const char percent_rankName[] = "percent_rank";
+static const char cume_distName[] =    "cume_dist";
+static const char ntileName[] =        "ntile";
+static const char last_valueName[] =   "last_value";
+static const char nth_valueName[] =    "nth_value";
+static const char first_valueName[] =  "first_value";
+static const char leadName[] =         "lead";
+static const char lagName[] =          "lag";
+
+/*
+** No-op implementations of xStep() and xFinalize().  Used as place-holders
+** for built-in window functions that never call those interfaces.
+**
+** The noopValueFunc() is called but is expected to do nothing.  The
+** noopStepFunc() is never called, and so it is marked with NO_TEST to
+** let the test coverage routine know not to expect this function to be
+** invoked.
+*/
+static void noopStepFunc(    /*NO_TEST*/
+  sqlite3_context *p,        /*NO_TEST*/
+  int n,                     /*NO_TEST*/
+  sqlite3_value **a          /*NO_TEST*/
+){                           /*NO_TEST*/
+  UNUSED_PARAMETER(p);       /*NO_TEST*/
+  UNUSED_PARAMETER(n);       /*NO_TEST*/
+  UNUSED_PARAMETER(a);       /*NO_TEST*/
+  assert(0);                 /*NO_TEST*/
+}                            /*NO_TEST*/
+static void noopValueFunc(sqlite3_context *p){ UNUSED_PARAMETER(p); /*no-op*/ }
+
+/* Window functions that use all window interfaces: xStep, xFinal,
+** xValue, and xInverse */
+#define WINDOWFUNCALL(name,nArg,extra) {                                   \
+  nArg, (SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_FUNC_WINDOW|extra), 0, 0,  \
+  name ## StepFunc, name ## FinalizeFunc, name ## ValueFunc,               \
+  name ## InvFunc, name ## Name, {0}                                       \
+}
+
+/* Window functions that are implemented using bytecode and thus have
+** no-op routines for their methods */
+#define WINDOWFUNCNOOP(name,nArg,extra) {                                  \
+  nArg, (SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_FUNC_WINDOW|extra), 0, 0,  \
+  noopStepFunc, noopValueFunc, noopValueFunc,                              \
+  noopStepFunc, name ## Name, {0}                                          \
+}
+
+/* Window functions that use all window interfaces: xStep, the
+** same routine for xFinalize and xValue and which never call
+** xInverse. */
+#define WINDOWFUNCX(name,nArg,extra) {                                     \
+  nArg, (SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_FUNC_WINDOW|extra), 0, 0,  \
+  name ## StepFunc, name ## ValueFunc, name ## ValueFunc,                  \
+  noopStepFunc, name ## Name, {0}                                          \
+}
+
+
+/*
+** Register those built-in window functions that are not also aggregates.
+*/
+SQLITE_PRIVATE void sqlite3WindowFunctions(void){
+  static FuncDef aWindowFuncs[] = {
+    WINDOWFUNCX(row_number, 0, 0),
+    WINDOWFUNCX(dense_rank, 0, 0),
+    WINDOWFUNCX(rank, 0, 0),
+    WINDOWFUNCALL(percent_rank, 0, 0),
+    WINDOWFUNCALL(cume_dist, 0, 0),
+    WINDOWFUNCALL(ntile, 1, 0),
+    WINDOWFUNCALL(last_value, 1, 0),
+    WINDOWFUNCALL(nth_value, 2, 0),
+    WINDOWFUNCALL(first_value, 1, 0),
+    WINDOWFUNCNOOP(lead, 1, 0),
+    WINDOWFUNCNOOP(lead, 2, 0),
+    WINDOWFUNCNOOP(lead, 3, 0),
+    WINDOWFUNCNOOP(lag, 1, 0),
+    WINDOWFUNCNOOP(lag, 2, 0),
+    WINDOWFUNCNOOP(lag, 3, 0),
+  };
+  sqlite3InsertBuiltinFuncs(aWindowFuncs, ArraySize(aWindowFuncs));
+}
+
+static Window *windowFind(Parse *pParse, Window *pList, const char *zName){
+  Window *p;
+  for(p=pList; p; p=p->pNextWin){
+    if( sqlite3StrICmp(p->zName, zName)==0 ) break;
+  }
+  if( p==0 ){
+    sqlite3ErrorMsg(pParse, "no such window: %s", zName);
+  }
+  return p;
+}
+
+/*
+** This function is called immediately after resolving the function name
+** for a window function within a SELECT statement. Argument pList is a
+** linked list of WINDOW definitions for the current SELECT statement.
+** Argument pFunc is the function definition just resolved and pWin
+** is the Window object representing the associated OVER clause. This
+** function updates the contents of pWin as follows:
+**
+**   * If the OVER clause referred to a named window (as in "max(x) OVER win"),
+**     search list pList for a matching WINDOW definition, and update pWin
+**     accordingly. If no such WINDOW clause can be found, leave an error
+**     in pParse.
+**
+**   * If the function is a built-in window function that requires the
+**     window to be coerced (see "BUILT-IN WINDOW FUNCTIONS" at the top
+**     of this file), pWin is updated here.
+*/
+SQLITE_PRIVATE void sqlite3WindowUpdate(
+  Parse *pParse,
+  Window *pList,                  /* List of named windows for this SELECT */
+  Window *pWin,                   /* Window frame to update */
+  FuncDef *pFunc                  /* Window function definition */
+){
+  if( pWin->zName && pWin->eFrmType==0 ){
+    Window *p = windowFind(pParse, pList, pWin->zName);
+    if( p==0 ) return;
+    pWin->pPartition = sqlite3ExprListDup(pParse->db, p->pPartition, 0);
+    pWin->pOrderBy = sqlite3ExprListDup(pParse->db, p->pOrderBy, 0);
+    pWin->pStart = sqlite3ExprDup(pParse->db, p->pStart, 0);
+    pWin->pEnd = sqlite3ExprDup(pParse->db, p->pEnd, 0);
+    pWin->eStart = p->eStart;
+    pWin->eEnd = p->eEnd;
+    pWin->eFrmType = p->eFrmType;
+    pWin->eExclude = p->eExclude;
+  }else{
+    sqlite3WindowChain(pParse, pWin, pList);
+  }
+  if( (pWin->eFrmType==TK_RANGE)
+   && (pWin->pStart || pWin->pEnd)
+   && (pWin->pOrderBy==0 || pWin->pOrderBy->nExpr!=1)
+  ){
+    sqlite3ErrorMsg(pParse,
+      "RANGE with offset PRECEDING/FOLLOWING requires one ORDER BY expression"
+    );
+  }else
+  if( pFunc->funcFlags & SQLITE_FUNC_WINDOW ){
+    sqlite3 *db = pParse->db;
+    if( pWin->pFilter ){
+      sqlite3ErrorMsg(pParse,
+          "FILTER clause may only be used with aggregate window functions"
+      );
+    }else{
+      struct WindowUpdate {
+        const char *zFunc;
+        int eFrmType;
+        int eStart;
+        int eEnd;
+      } aUp[] = {
+        { row_numberName,   TK_ROWS,   TK_UNBOUNDED, TK_CURRENT },
+        { dense_rankName,   TK_RANGE,  TK_UNBOUNDED, TK_CURRENT },
+        { rankName,         TK_RANGE,  TK_UNBOUNDED, TK_CURRENT },
+        { percent_rankName, TK_GROUPS, TK_CURRENT,   TK_UNBOUNDED },
+        { cume_distName,    TK_GROUPS, TK_FOLLOWING, TK_UNBOUNDED },
+        { ntileName,        TK_ROWS,   TK_CURRENT,   TK_UNBOUNDED },
+        { leadName,         TK_ROWS,   TK_UNBOUNDED, TK_UNBOUNDED },
+        { lagName,          TK_ROWS,   TK_UNBOUNDED, TK_CURRENT },
+      };
+      int i;
+      for(i=0; i<ArraySize(aUp); i++){
+        if( pFunc->zName==aUp[i].zFunc ){
+          sqlite3ExprDelete(db, pWin->pStart);
+          sqlite3ExprDelete(db, pWin->pEnd);
+          pWin->pEnd = pWin->pStart = 0;
+          pWin->eFrmType = aUp[i].eFrmType;
+          pWin->eStart = aUp[i].eStart;
+          pWin->eEnd = aUp[i].eEnd;
+          pWin->eExclude = 0;
+          if( pWin->eStart==TK_FOLLOWING ){
+            pWin->pStart = sqlite3Expr(db, TK_INTEGER, "1");
+          }
+          break;
+        }
+      }
+    }
+  }
+  pWin->pWFunc = pFunc;
+}
+
+/*
+** Context object passed through sqlite3WalkExprList() to
+** selectWindowRewriteExprCb() by selectWindowRewriteEList().
+*/
+typedef struct WindowRewrite WindowRewrite;
+struct WindowRewrite {
+  Window *pWin;
+  SrcList *pSrc;
+  ExprList *pSub;
+  Table *pTab;
+  Select *pSubSelect;             /* Current sub-select, if any */
+};
+
+/*
+** Callback function used by selectWindowRewriteEList(). If necessary,
+** this function appends to the output expression-list and updates
+** expression (*ppExpr) in place.
+*/
+static int selectWindowRewriteExprCb(Walker *pWalker, Expr *pExpr){
+  struct WindowRewrite *p = pWalker->u.pRewrite;
+  Parse *pParse = pWalker->pParse;
+  assert( p!=0 );
+  assert( p->pWin!=0 );
+
+  /* If this function is being called from within a scalar sub-select
+  ** that used by the SELECT statement being processed, only process
+  ** TK_COLUMN expressions that refer to it (the outer SELECT). Do
+  ** not process aggregates or window functions at all, as they belong
+  ** to the scalar sub-select.  */
+  if( p->pSubSelect ){
+    if( pExpr->op!=TK_COLUMN ){
+      return WRC_Continue;
+    }else{
+      int nSrc = p->pSrc->nSrc;
+      int i;
+      for(i=0; i<nSrc; i++){
+        if( pExpr->iTable==p->pSrc->a[i].iCursor ) break;
+      }
+      if( i==nSrc ) return WRC_Continue;
+    }
+  }
+
+  switch( pExpr->op ){
+
+    case TK_FUNCTION:
+      if( !ExprHasProperty(pExpr, EP_WinFunc) ){
+        break;
+      }else{
+        Window *pWin;
+        for(pWin=p->pWin; pWin; pWin=pWin->pNextWin){
+          if( pExpr->y.pWin==pWin ){
+            assert( pWin->pOwner==pExpr );
+            return WRC_Prune;
+          }
+        }
+      }
+      /* no break */ deliberate_fall_through
+
+    case TK_IF_NULL_ROW:
+    case TK_AGG_FUNCTION:
+    case TK_COLUMN: {
+      int iCol = -1;
+      if( pParse->db->mallocFailed ) return WRC_Abort;
+      if( p->pSub ){
+        int i;
+        for(i=0; i<p->pSub->nExpr; i++){
+          if( 0==sqlite3ExprCompare(0, p->pSub->a[i].pExpr, pExpr, -1) ){
+            iCol = i;
+            break;
+          }
+        }
+      }
+      if( iCol<0 ){
+        Expr *pDup = sqlite3ExprDup(pParse->db, pExpr, 0);
+        if( pDup && pDup->op==TK_AGG_FUNCTION ) pDup->op = TK_FUNCTION;
+        p->pSub = sqlite3ExprListAppend(pParse, p->pSub, pDup);
+      }
+      if( p->pSub ){
+        int f = pExpr->flags & EP_Collate;
+        assert( ExprHasProperty(pExpr, EP_Static)==0 );
+        ExprSetProperty(pExpr, EP_Static);
+        sqlite3ExprDelete(pParse->db, pExpr);
+        ExprClearProperty(pExpr, EP_Static);
+        memset(pExpr, 0, sizeof(Expr));
+
+        pExpr->op = TK_COLUMN;
+        pExpr->iColumn = (iCol<0 ? p->pSub->nExpr-1: iCol);
+        pExpr->iTable = p->pWin->iEphCsr;
+        pExpr->y.pTab = p->pTab;
+        pExpr->flags = f;
+      }
+      if( pParse->db->mallocFailed ) return WRC_Abort;
+      break;
+    }
+
+    default: /* no-op */
+      break;
+  }
+
+  return WRC_Continue;
+}
+static int selectWindowRewriteSelectCb(Walker *pWalker, Select *pSelect){
+  struct WindowRewrite *p = pWalker->u.pRewrite;
+  Select *pSave = p->pSubSelect;
+  if( pSave==pSelect ){
+    return WRC_Continue;
+  }else{
+    p->pSubSelect = pSelect;
+    sqlite3WalkSelect(pWalker, pSelect);
+    p->pSubSelect = pSave;
+  }
+  return WRC_Prune;
+}
+
+
+/*
+** Iterate through each expression in expression-list pEList. For each:
+**
+**   * TK_COLUMN,
+**   * aggregate function, or
+**   * window function with a Window object that is not a member of the
+**     Window list passed as the second argument (pWin).
+**
+** Append the node to output expression-list (*ppSub). And replace it
+** with a TK_COLUMN that reads the (N-1)th element of table
+** pWin->iEphCsr, where N is the number of elements in (*ppSub) after
+** appending the new one.
+*/
+static void selectWindowRewriteEList(
+  Parse *pParse,
+  Window *pWin,
+  SrcList *pSrc,
+  ExprList *pEList,               /* Rewrite expressions in this list */
+  Table *pTab,
+  ExprList **ppSub                /* IN/OUT: Sub-select expression-list */
+){
+  Walker sWalker;
+  WindowRewrite sRewrite;
+
+  assert( pWin!=0 );
+  memset(&sWalker, 0, sizeof(Walker));
+  memset(&sRewrite, 0, sizeof(WindowRewrite));
+
+  sRewrite.pSub = *ppSub;
+  sRewrite.pWin = pWin;
+  sRewrite.pSrc = pSrc;
+  sRewrite.pTab = pTab;
+
+  sWalker.pParse = pParse;
+  sWalker.xExprCallback = selectWindowRewriteExprCb;
+  sWalker.xSelectCallback = selectWindowRewriteSelectCb;
+  sWalker.u.pRewrite = &sRewrite;
+
+  (void)sqlite3WalkExprList(&sWalker, pEList);
+
+  *ppSub = sRewrite.pSub;
+}
+
+/*
+** Append a copy of each expression in expression-list pAppend to
+** expression list pList. Return a pointer to the result list.
+*/
+static ExprList *exprListAppendList(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to append. Might be NULL */
+  ExprList *pAppend,      /* List of values to append. Might be NULL */
+  int bIntToNull
+){
+  if( pAppend ){
+    int i;
+    int nInit = pList ? pList->nExpr : 0;
+    for(i=0; i<pAppend->nExpr; i++){
+      sqlite3 *db = pParse->db;
+      Expr *pDup = sqlite3ExprDup(db, pAppend->a[i].pExpr, 0);
+      if( db->mallocFailed ){
+        sqlite3ExprDelete(db, pDup);
+        break;
+      }
+      if( bIntToNull ){
+        int iDummy;
+        Expr *pSub;
+        pSub = sqlite3ExprSkipCollateAndLikely(pDup);
+        if( sqlite3ExprIsInteger(pSub, &iDummy, 0) ){
+          pSub->op = TK_NULL;
+          pSub->flags &= ~(EP_IntValue|EP_IsTrue|EP_IsFalse);
+          pSub->u.zToken = 0;
+        }
+      }
+      pList = sqlite3ExprListAppend(pParse, pList, pDup);
+      if( pList ) pList->a[nInit+i].fg.sortFlags = pAppend->a[i].fg.sortFlags;
+    }
+  }
+  return pList;
+}
+
+/*
+** When rewriting a query, if the new subquery in the FROM clause
+** contains TK_AGG_FUNCTION nodes that refer to an outer query,
+** then we have to increase the Expr->op2 values of those nodes
+** due to the extra subquery layer that was added.
+**
+** See also the incrAggDepth() routine in resolve.c
+*/
+static int sqlite3WindowExtraAggFuncDepth(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_AGG_FUNCTION
+   && pExpr->op2>=pWalker->walkerDepth
+  ){
+    pExpr->op2++;
+  }
+  return WRC_Continue;
+}
+
+static int disallowAggregatesInOrderByCb(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_AGG_FUNCTION && pExpr->pAggInfo==0 ){
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+     sqlite3ErrorMsg(pWalker->pParse,
+         "misuse of aggregate: %s()", pExpr->u.zToken);
+  }
+  return WRC_Continue;
+}
+
+/*
+** If the SELECT statement passed as the second argument does not invoke
+** any SQL window functions, this function is a no-op. Otherwise, it
+** rewrites the SELECT statement so that window function xStep functions
+** are invoked in the correct order as described under "SELECT REWRITING"
+** at the top of this file.
+*/
+SQLITE_PRIVATE int sqlite3WindowRewrite(Parse *pParse, Select *p){
+  int rc = SQLITE_OK;
+  if( p->pWin
+   && p->pPrior==0
+   && ALWAYS((p->selFlags & SF_WinRewrite)==0)
+   && ALWAYS(!IN_RENAME_OBJECT)
+  ){
+    Vdbe *v = sqlite3GetVdbe(pParse);
+    sqlite3 *db = pParse->db;
+    Select *pSub = 0;             /* The subquery */
+    SrcList *pSrc = p->pSrc;
+    Expr *pWhere = p->pWhere;
+    ExprList *pGroupBy = p->pGroupBy;
+    Expr *pHaving = p->pHaving;
+    ExprList *pSort = 0;
+
+    ExprList *pSublist = 0;       /* Expression list for sub-query */
+    Window *pMWin = p->pWin;      /* Main window object */
+    Window *pWin;                 /* Window object iterator */
+    Table *pTab;
+    Walker w;
+
+    u32 selFlags = p->selFlags;
+
+    pTab = sqlite3DbMallocZero(db, sizeof(Table));
+    if( pTab==0 ){
+      return sqlite3ErrorToParser(db, SQLITE_NOMEM);
+    }
+    sqlite3AggInfoPersistWalkerInit(&w, pParse);
+    sqlite3WalkSelect(&w, p);
+    if( (p->selFlags & SF_Aggregate)==0 ){
+      w.xExprCallback = disallowAggregatesInOrderByCb;
+      w.xSelectCallback = 0;
+      sqlite3WalkExprList(&w, p->pOrderBy);
+    }
+
+    p->pSrc = 0;
+    p->pWhere = 0;
+    p->pGroupBy = 0;
+    p->pHaving = 0;
+    p->selFlags &= ~SF_Aggregate;
+    p->selFlags |= SF_WinRewrite;
+
+    /* Create the ORDER BY clause for the sub-select. This is the concatenation
+    ** of the window PARTITION and ORDER BY clauses. Then, if this makes it
+    ** redundant, remove the ORDER BY from the parent SELECT.  */
+    pSort = exprListAppendList(pParse, 0, pMWin->pPartition, 1);
+    pSort = exprListAppendList(pParse, pSort, pMWin->pOrderBy, 1);
+    if( pSort && p->pOrderBy && p->pOrderBy->nExpr<=pSort->nExpr ){
+      int nSave = pSort->nExpr;
+      pSort->nExpr = p->pOrderBy->nExpr;
+      if( sqlite3ExprListCompare(pSort, p->pOrderBy, -1)==0 ){
+        sqlite3ExprListDelete(db, p->pOrderBy);
+        p->pOrderBy = 0;
+      }
+      pSort->nExpr = nSave;
+    }
+
+    /* Assign a cursor number for the ephemeral table used to buffer rows.
+    ** The OpenEphemeral instruction is coded later, after it is known how
+    ** many columns the table will have.  */
+    pMWin->iEphCsr = pParse->nTab++;
+    pParse->nTab += 3;
+
+    selectWindowRewriteEList(pParse, pMWin, pSrc, p->pEList, pTab, &pSublist);
+    selectWindowRewriteEList(pParse, pMWin, pSrc, p->pOrderBy, pTab, &pSublist);
+    pMWin->nBufferCol = (pSublist ? pSublist->nExpr : 0);
+
+    /* Append the PARTITION BY and ORDER BY expressions to the to the
+    ** sub-select expression list. They are required to figure out where
+    ** boundaries for partitions and sets of peer rows lie.  */
+    pSublist = exprListAppendList(pParse, pSublist, pMWin->pPartition, 0);
+    pSublist = exprListAppendList(pParse, pSublist, pMWin->pOrderBy, 0);
+
+    /* Append the arguments passed to each window function to the
+    ** sub-select expression list. Also allocate two registers for each
+    ** window function - one for the accumulator, another for interim
+    ** results.  */
+    for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+      ExprList *pArgs;
+      assert( ExprUseXList(pWin->pOwner) );
+      assert( pWin->pWFunc!=0 );
+      pArgs = pWin->pOwner->x.pList;
+      if( pWin->pWFunc->funcFlags & SQLITE_SUBTYPE ){
+        selectWindowRewriteEList(pParse, pMWin, pSrc, pArgs, pTab, &pSublist);
+        pWin->iArgCol = (pSublist ? pSublist->nExpr : 0);
+        pWin->bExprArgs = 1;
+      }else{
+        pWin->iArgCol = (pSublist ? pSublist->nExpr : 0);
+        pSublist = exprListAppendList(pParse, pSublist, pArgs, 0);
+      }
+      if( pWin->pFilter ){
+        Expr *pFilter = sqlite3ExprDup(db, pWin->pFilter, 0);
+        pSublist = sqlite3ExprListAppend(pParse, pSublist, pFilter);
+      }
+      pWin->regAccum = ++pParse->nMem;
+      pWin->regResult = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
+    }
+
+    /* If there is no ORDER BY or PARTITION BY clause, and the window
+    ** function accepts zero arguments, and there are no other columns
+    ** selected (e.g. "SELECT row_number() OVER () FROM t1"), it is possible
+    ** that pSublist is still NULL here. Add a constant expression here to
+    ** keep everything legal in this case.
+    */
+    if( pSublist==0 ){
+      pSublist = sqlite3ExprListAppend(pParse, 0,
+        sqlite3Expr(db, TK_INTEGER, "0")
+      );
+    }
+
+    pSub = sqlite3SelectNew(
+        pParse, pSublist, pSrc, pWhere, pGroupBy, pHaving, pSort, 0, 0
+    );
+    TREETRACE(0x40,pParse,pSub,
+       ("New window-function subquery in FROM clause of (%u/%p)\n",
+       p->selId, p));
+    p->pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
+    assert( pSub!=0 || p->pSrc==0 ); /* Due to db->mallocFailed test inside
+                                     ** of sqlite3DbMallocRawNN() called from
+                                     ** sqlite3SrcListAppend() */
+    if( p->pSrc==0 ){
+      sqlite3SelectDelete(db, pSub);
+    }else if( sqlite3SrcItemAttachSubquery(pParse, &p->pSrc->a[0], pSub, 0) ){
+      Table *pTab2;
+      p->pSrc->a[0].fg.isCorrelated = 1;
+      sqlite3SrcListAssignCursors(pParse, p->pSrc);
+      pSub->selFlags |= SF_Expanded|SF_OrderByReqd;
+      pTab2 = sqlite3ResultSetOfSelect(pParse, pSub, SQLITE_AFF_NONE);
+      pSub->selFlags |= (selFlags & SF_Aggregate);
+      if( pTab2==0 ){
+        /* Might actually be some other kind of error, but in that case
+        ** pParse->nErr will be set, so if SQLITE_NOMEM is set, we will get
+        ** the correct error message regardless. */
+        rc = SQLITE_NOMEM;
+      }else{
+        memcpy(pTab, pTab2, sizeof(Table));
+        pTab->tabFlags |= TF_Ephemeral;
+        p->pSrc->a[0].pSTab = pTab;
+        pTab = pTab2;
+        memset(&w, 0, sizeof(w));
+        w.xExprCallback = sqlite3WindowExtraAggFuncDepth;
+        w.xSelectCallback = sqlite3WalkerDepthIncrease;
+        w.xSelectCallback2 = sqlite3WalkerDepthDecrease;
+        sqlite3WalkSelect(&w, pSub);
+      }
+    }
+    if( db->mallocFailed ) rc = SQLITE_NOMEM;
+
+    /* Defer deleting the temporary table pTab because if an error occurred,
+    ** there could still be references to that table embedded in the
+    ** result-set or ORDER BY clause of the SELECT statement p.  */
+    sqlite3ParserAddCleanup(pParse, sqlite3DbFree, pTab);
+  }
+
+  assert( rc==SQLITE_OK || pParse->nErr!=0 );
+  return rc;
+}
+
+/*
+** Unlink the Window object from the Select to which it is attached,
+** if it is attached.
+*/
+SQLITE_PRIVATE void sqlite3WindowUnlinkFromSelect(Window *p){
+  if( p->ppThis ){
+    *p->ppThis = p->pNextWin;
+    if( p->pNextWin ) p->pNextWin->ppThis = p->ppThis;
+    p->ppThis = 0;
+  }
+}
+
+/*
+** Free the Window object passed as the second argument.
+*/
+SQLITE_PRIVATE void sqlite3WindowDelete(sqlite3 *db, Window *p){
+  if( p ){
+    sqlite3WindowUnlinkFromSelect(p);
+    sqlite3ExprDelete(db, p->pFilter);
+    sqlite3ExprListDelete(db, p->pPartition);
+    sqlite3ExprListDelete(db, p->pOrderBy);
+    sqlite3ExprDelete(db, p->pEnd);
+    sqlite3ExprDelete(db, p->pStart);
+    sqlite3DbFree(db, p->zName);
+    sqlite3DbFree(db, p->zBase);
+    sqlite3DbFree(db, p);
+  }
+}
+
+/*
+** Free the linked list of Window objects starting at the second argument.
+*/
+SQLITE_PRIVATE void sqlite3WindowListDelete(sqlite3 *db, Window *p){
+  while( p ){
+    Window *pNext = p->pNextWin;
+    sqlite3WindowDelete(db, p);
+    p = pNext;
+  }
+}
+
+/*
+** The argument expression is an PRECEDING or FOLLOWING offset.  The
+** value should be a non-negative integer.  If the value is not a
+** constant, change it to NULL.  The fact that it is then a non-negative
+** integer will be caught later.  But it is important not to leave
+** variable values in the expression tree.
+*/
+static Expr *sqlite3WindowOffsetExpr(Parse *pParse, Expr *pExpr){
+  if( 0==sqlite3ExprIsConstant(0,pExpr) ){
+    if( IN_RENAME_OBJECT ) sqlite3RenameExprUnmap(pParse, pExpr);
+    sqlite3ExprDelete(pParse->db, pExpr);
+    pExpr = sqlite3ExprAlloc(pParse->db, TK_NULL, 0, 0);
+  }
+  return pExpr;
+}
+
+/*
+** Allocate and return a new Window object describing a Window Definition.
+*/
+SQLITE_PRIVATE Window *sqlite3WindowAlloc(
+  Parse *pParse,    /* Parsing context */
+  int eType,        /* Frame type. TK_RANGE, TK_ROWS, TK_GROUPS, or 0 */
+  int eStart,       /* Start type: CURRENT, PRECEDING, FOLLOWING, UNBOUNDED */
+  Expr *pStart,     /* Start window size if TK_PRECEDING or FOLLOWING */
+  int eEnd,         /* End type: CURRENT, FOLLOWING, TK_UNBOUNDED, PRECEDING */
+  Expr *pEnd,       /* End window size if TK_FOLLOWING or PRECEDING */
+  u8 eExclude       /* EXCLUDE clause */
+){
+  Window *pWin = 0;
+  int bImplicitFrame = 0;
+
+  /* Parser assures the following: */
+  assert( eType==0 || eType==TK_RANGE || eType==TK_ROWS || eType==TK_GROUPS );
+  assert( eStart==TK_CURRENT || eStart==TK_PRECEDING
+           || eStart==TK_UNBOUNDED || eStart==TK_FOLLOWING );
+  assert( eEnd==TK_CURRENT || eEnd==TK_FOLLOWING
+           || eEnd==TK_UNBOUNDED || eEnd==TK_PRECEDING );
+  assert( (eStart==TK_PRECEDING || eStart==TK_FOLLOWING)==(pStart!=0) );
+  assert( (eEnd==TK_FOLLOWING || eEnd==TK_PRECEDING)==(pEnd!=0) );
+
+  if( eType==0 ){
+    bImplicitFrame = 1;
+    eType = TK_RANGE;
+  }
+
+  /* Additionally, the
+  ** starting boundary type may not occur earlier in the following list than
+  ** the ending boundary type:
+  **
+  **   UNBOUNDED PRECEDING
+  **   <expr> PRECEDING
+  **   CURRENT ROW
+  **   <expr> FOLLOWING
+  **   UNBOUNDED FOLLOWING
+  **
+  ** The parser ensures that "UNBOUNDED PRECEDING" cannot be used as an ending
+  ** boundary, and than "UNBOUNDED FOLLOWING" cannot be used as a starting
+  ** frame boundary.
+  */
+  if( (eStart==TK_CURRENT && eEnd==TK_PRECEDING)
+   || (eStart==TK_FOLLOWING && (eEnd==TK_PRECEDING || eEnd==TK_CURRENT))
+  ){
+    sqlite3ErrorMsg(pParse, "unsupported frame specification");
+    goto windowAllocErr;
+  }
+
+  pWin = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
+  if( pWin==0 ) goto windowAllocErr;
+  pWin->eFrmType = eType;
+  pWin->eStart = eStart;
+  pWin->eEnd = eEnd;
+  if( eExclude==0 && OptimizationDisabled(pParse->db, SQLITE_WindowFunc) ){
+    eExclude = TK_NO;
+  }
+  pWin->eExclude = eExclude;
+  pWin->bImplicitFrame = bImplicitFrame;
+  pWin->pEnd = sqlite3WindowOffsetExpr(pParse, pEnd);
+  pWin->pStart = sqlite3WindowOffsetExpr(pParse, pStart);
+  return pWin;
+
+windowAllocErr:
+  sqlite3ExprDelete(pParse->db, pEnd);
+  sqlite3ExprDelete(pParse->db, pStart);
+  return 0;
+}
+
+/*
+** Attach PARTITION and ORDER BY clauses pPartition and pOrderBy to window
+** pWin. Also, if parameter pBase is not NULL, set pWin->zBase to the
+** equivalent nul-terminated string.
+*/
+SQLITE_PRIVATE Window *sqlite3WindowAssemble(
+  Parse *pParse,
+  Window *pWin,
+  ExprList *pPartition,
+  ExprList *pOrderBy,
+  Token *pBase
+){
+  if( pWin ){
+    pWin->pPartition = pPartition;
+    pWin->pOrderBy = pOrderBy;
+    if( pBase ){
+      pWin->zBase = sqlite3DbStrNDup(pParse->db, pBase->z, pBase->n);
+    }
+  }else{
+    sqlite3ExprListDelete(pParse->db, pPartition);
+    sqlite3ExprListDelete(pParse->db, pOrderBy);
+  }
+  return pWin;
+}
+
+/*
+** Window *pWin has just been created from a WINDOW clause. Token pBase
+** is the base window. Earlier windows from the same WINDOW clause are
+** stored in the linked list starting at pWin->pNextWin. This function
+** either updates *pWin according to the base specification, or else
+** leaves an error in pParse.
+*/
+SQLITE_PRIVATE void sqlite3WindowChain(Parse *pParse, Window *pWin, Window *pList){
+  if( pWin->zBase ){
+    sqlite3 *db = pParse->db;
+    Window *pExist = windowFind(pParse, pList, pWin->zBase);
+    if( pExist ){
+      const char *zErr = 0;
+      /* Check for errors */
+      if( pWin->pPartition ){
+        zErr = "PARTITION clause";
+      }else if( pExist->pOrderBy && pWin->pOrderBy ){
+        zErr = "ORDER BY clause";
+      }else if( pExist->bImplicitFrame==0 ){
+        zErr = "frame specification";
+      }
+      if( zErr ){
+        sqlite3ErrorMsg(pParse,
+            "cannot override %s of window: %s", zErr, pWin->zBase
+        );
+      }else{
+        pWin->pPartition = sqlite3ExprListDup(db, pExist->pPartition, 0);
+        if( pExist->pOrderBy ){
+          assert( pWin->pOrderBy==0 );
+          pWin->pOrderBy = sqlite3ExprListDup(db, pExist->pOrderBy, 0);
+        }
+        sqlite3DbFree(db, pWin->zBase);
+        pWin->zBase = 0;
+      }
+    }
+  }
+}
+
+/*
+** Attach window object pWin to expression p.
+*/
+SQLITE_PRIVATE void sqlite3WindowAttach(Parse *pParse, Expr *p, Window *pWin){
+  if( p ){
+    assert( p->op==TK_FUNCTION );
+    assert( pWin );
+    assert( ExprIsFullSize(p) );
+    p->y.pWin = pWin;
+    ExprSetProperty(p, EP_WinFunc|EP_FullSize);
+    pWin->pOwner = p;
+    if( (p->flags & EP_Distinct) && pWin->eFrmType!=TK_FILTER ){
+      sqlite3ErrorMsg(pParse,
+          "DISTINCT is not supported for window functions"
+      );
+    }
+  }else{
+    sqlite3WindowDelete(pParse->db, pWin);
+  }
+}
+
+/*
+** Possibly link window pWin into the list at pSel->pWin (window functions
+** to be processed as part of SELECT statement pSel). The window is linked
+** in if either (a) there are no other windows already linked to this
+** SELECT, or (b) the windows already linked use a compatible window frame.
+*/
+SQLITE_PRIVATE void sqlite3WindowLink(Select *pSel, Window *pWin){
+  if( pSel ){
+    if( 0==pSel->pWin || 0==sqlite3WindowCompare(0, pSel->pWin, pWin, 0) ){
+      pWin->pNextWin = pSel->pWin;
+      if( pSel->pWin ){
+        pSel->pWin->ppThis = &pWin->pNextWin;
+      }
+      pSel->pWin = pWin;
+      pWin->ppThis = &pSel->pWin;
+    }else{
+      if( sqlite3ExprListCompare(pWin->pPartition, pSel->pWin->pPartition,-1) ){
+        pSel->selFlags |= SF_MultiPart;
+      }
+    }
+  }
+}
+
+/*
+** Return 0 if the two window objects are identical, 1 if they are
+** different, or 2 if it cannot be determined if the objects are identical
+** or not. Identical window objects can be processed in a single scan.
+*/
+SQLITE_PRIVATE int sqlite3WindowCompare(
+  const Parse *pParse,
+  const Window *p1,
+  const Window *p2,
+  int bFilter
+){
+  int res;
+  if( NEVER(p1==0) || NEVER(p2==0) ) return 1;
+  if( p1->eFrmType!=p2->eFrmType ) return 1;
+  if( p1->eStart!=p2->eStart ) return 1;
+  if( p1->eEnd!=p2->eEnd ) return 1;
+  if( p1->eExclude!=p2->eExclude ) return 1;
+  if( sqlite3ExprCompare(pParse, p1->pStart, p2->pStart, -1) ) return 1;
+  if( sqlite3ExprCompare(pParse, p1->pEnd, p2->pEnd, -1) ) return 1;
+  if( (res = sqlite3ExprListCompare(p1->pPartition, p2->pPartition, -1)) ){
+    return res;
+  }
+  if( (res = sqlite3ExprListCompare(p1->pOrderBy, p2->pOrderBy, -1)) ){
+    return res;
+  }
+  if( bFilter ){
+    if( (res = sqlite3ExprCompare(pParse, p1->pFilter, p2->pFilter, -1)) ){
+      return res;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** This is called by code in select.c before it calls sqlite3WhereBegin()
+** to begin iterating through the sub-query results. It is used to allocate
+** and initialize registers and cursors used by sqlite3WindowCodeStep().
+*/
+SQLITE_PRIVATE void sqlite3WindowCodeInit(Parse *pParse, Select *pSelect){
+  Window *pWin;
+  int nEphExpr;
+  Window *pMWin;
+  Vdbe *v;
+
+  assert( pSelect->pSrc->a[0].fg.isSubquery );
+  nEphExpr = pSelect->pSrc->a[0].u4.pSubq->pSelect->pEList->nExpr;
+  pMWin = pSelect->pWin;
+  v = sqlite3GetVdbe(pParse);
+
+  sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pMWin->iEphCsr, nEphExpr);
+  sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+1, pMWin->iEphCsr);
+  sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+2, pMWin->iEphCsr);
+  sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+3, pMWin->iEphCsr);
+
+  /* Allocate registers to use for PARTITION BY values, if any. Initialize
+  ** said registers to NULL.  */
+  if( pMWin->pPartition ){
+    int nExpr = pMWin->pPartition->nExpr;
+    pMWin->regPart = pParse->nMem+1;
+    pParse->nMem += nExpr;
+    sqlite3VdbeAddOp3(v, OP_Null, 0, pMWin->regPart, pMWin->regPart+nExpr-1);
+  }
+
+  pMWin->regOne = ++pParse->nMem;
+  sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regOne);
+
+  if( pMWin->eExclude ){
+    pMWin->regStartRowid = ++pParse->nMem;
+    pMWin->regEndRowid = ++pParse->nMem;
+    pMWin->csrApp = pParse->nTab++;
+    sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regStartRowid);
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, pMWin->regEndRowid);
+    sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->csrApp, pMWin->iEphCsr);
+    return;
+  }
+
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    FuncDef *p = pWin->pWFunc;
+    if( (p->funcFlags & SQLITE_FUNC_MINMAX) && pWin->eStart!=TK_UNBOUNDED ){
+      /* The inline versions of min() and max() require a single ephemeral
+      ** table and 3 registers. The registers are used as follows:
+      **
+      **   regApp+0: slot to copy min()/max() argument to for MakeRecord
+      **   regApp+1: integer value used to ensure keys are unique
+      **   regApp+2: output of MakeRecord
+      */
+      ExprList *pList;
+      KeyInfo *pKeyInfo;
+      assert( ExprUseXList(pWin->pOwner) );
+      pList = pWin->pOwner->x.pList;
+      pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pList, 0, 0);
+      pWin->csrApp = pParse->nTab++;
+      pWin->regApp = pParse->nMem+1;
+      pParse->nMem += 3;
+      if( pKeyInfo && pWin->pWFunc->zName[1]=='i' ){
+        assert( pKeyInfo->aSortFlags[0]==0 );
+        pKeyInfo->aSortFlags[0] = KEYINFO_ORDER_DESC;
+      }
+      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pWin->csrApp, 2);
+      sqlite3VdbeAppendP4(v, pKeyInfo, P4_KEYINFO);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1);
+    }
+    else if( p->zName==nth_valueName || p->zName==first_valueName ){
+      /* Allocate two registers at pWin->regApp. These will be used to
+      ** store the start and end index of the current frame.  */
+      pWin->regApp = pParse->nMem+1;
+      pWin->csrApp = pParse->nTab++;
+      pParse->nMem += 2;
+      sqlite3VdbeAddOp2(v, OP_OpenDup, pWin->csrApp, pMWin->iEphCsr);
+    }
+    else if( p->zName==leadName || p->zName==lagName ){
+      pWin->csrApp = pParse->nTab++;
+      sqlite3VdbeAddOp2(v, OP_OpenDup, pWin->csrApp, pMWin->iEphCsr);
+    }
+  }
+}
+
+#define WINDOW_STARTING_INT  0
+#define WINDOW_ENDING_INT    1
+#define WINDOW_NTH_VALUE_INT 2
+#define WINDOW_STARTING_NUM  3
+#define WINDOW_ENDING_NUM    4
+
+/*
+** A "PRECEDING <expr>" (eCond==0) or "FOLLOWING <expr>" (eCond==1) or the
+** value of the second argument to nth_value() (eCond==2) has just been
+** evaluated and the result left in register reg. This function generates VM
+** code to check that the value is a non-negative integer and throws an
+** exception if it is not.
+*/
+static void windowCheckValue(Parse *pParse, int reg, int eCond){
+  static const char *azErr[] = {
+    "frame starting offset must be a non-negative integer",
+    "frame ending offset must be a non-negative integer",
+    "second argument to nth_value must be a positive integer",
+    "frame starting offset must be a non-negative number",
+    "frame ending offset must be a non-negative number",
+  };
+  static int aOp[] = { OP_Ge, OP_Ge, OP_Gt, OP_Ge, OP_Ge };
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int regZero = sqlite3GetTempReg(pParse);
+  assert( eCond>=0 && eCond<ArraySize(azErr) );
+  sqlite3VdbeAddOp2(v, OP_Integer, 0, regZero);
+  if( eCond>=WINDOW_STARTING_NUM ){
+    int regString = sqlite3GetTempReg(pParse);
+    sqlite3VdbeAddOp4(v, OP_String8, 0, regString, 0, "", P4_STATIC);
+    sqlite3VdbeAddOp3(v, OP_Ge, regString, sqlite3VdbeCurrentAddr(v)+2, reg);
+    sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC|SQLITE_JUMPIFNULL);
+    VdbeCoverage(v);
+    assert( eCond==3 || eCond==4 );
+    VdbeCoverageIf(v, eCond==3);
+    VdbeCoverageIf(v, eCond==4);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_MustBeInt, reg, sqlite3VdbeCurrentAddr(v)+2);
+    VdbeCoverage(v);
+    assert( eCond==0 || eCond==1 || eCond==2 );
+    VdbeCoverageIf(v, eCond==0);
+    VdbeCoverageIf(v, eCond==1);
+    VdbeCoverageIf(v, eCond==2);
+  }
+  sqlite3VdbeAddOp3(v, aOp[eCond], regZero, sqlite3VdbeCurrentAddr(v)+2, reg);
+  sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC);
+  VdbeCoverageNeverNullIf(v, eCond==0); /* NULL case captured by */
+  VdbeCoverageNeverNullIf(v, eCond==1); /*   the OP_MustBeInt */
+  VdbeCoverageNeverNullIf(v, eCond==2);
+  VdbeCoverageNeverNullIf(v, eCond==3); /* NULL case caught by */
+  VdbeCoverageNeverNullIf(v, eCond==4); /*   the OP_Ge */
+  sqlite3MayAbort(pParse);
+  sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_ERROR, OE_Abort);
+  sqlite3VdbeAppendP4(v, (void*)azErr[eCond], P4_STATIC);
+  sqlite3ReleaseTempReg(pParse, regZero);
+}
+
+/*
+** Return the number of arguments passed to the window-function associated
+** with the object passed as the only argument to this function.
+*/
+static int windowArgCount(Window *pWin){
+  const ExprList *pList;
+  assert( ExprUseXList(pWin->pOwner) );
+  pList = pWin->pOwner->x.pList;
+  return (pList ? pList->nExpr : 0);
+}
+
+typedef struct WindowCodeArg WindowCodeArg;
+typedef struct WindowCsrAndReg WindowCsrAndReg;
+
+/*
+** See comments above struct WindowCodeArg.
+*/
+struct WindowCsrAndReg {
+  int csr;                        /* Cursor number */
+  int reg;                        /* First in array of peer values */
+};
+
+/*
+** A single instance of this structure is allocated on the stack by
+** sqlite3WindowCodeStep() and a pointer to it passed to the various helper
+** routines. This is to reduce the number of arguments required by each
+** helper function.
+**
+** regArg:
+**   Each window function requires an accumulator register (just as an
+**   ordinary aggregate function does). This variable is set to the first
+**   in an array of accumulator registers - one for each window function
+**   in the WindowCodeArg.pMWin list.
+**
+** eDelete:
+**   The window functions implementation sometimes caches the input rows
+**   that it processes in a temporary table. If it is not zero, this
+**   variable indicates when rows may be removed from the temp table (in
+**   order to reduce memory requirements - it would always be safe just
+**   to leave them there). Possible values for eDelete are:
+**
+**      WINDOW_RETURN_ROW:
+**        An input row can be discarded after it is returned to the caller.
+**
+**      WINDOW_AGGINVERSE:
+**        An input row can be discarded after the window functions xInverse()
+**        callbacks have been invoked in it.
+**
+**      WINDOW_AGGSTEP:
+**        An input row can be discarded after the window functions xStep()
+**        callbacks have been invoked in it.
+**
+** start,current,end
+**   Consider a window-frame similar to the following:
+**
+**     (ORDER BY a, b GROUPS BETWEEN 2 PRECEDING AND 2 FOLLOWING)
+**
+**   The windows functions implementation caches the input rows in a temp
+**   table, sorted by "a, b" (it actually populates the cache lazily, and
+**   aggressively removes rows once they are no longer required, but that's
+**   a mere detail). It keeps three cursors open on the temp table. One
+**   (current) that points to the next row to return to the query engine
+**   once its window function values have been calculated. Another (end)
+**   points to the next row to call the xStep() method of each window function
+**   on (so that it is 2 groups ahead of current). And a third (start) that
+**   points to the next row to call the xInverse() method of each window
+**   function on.
+**
+**   Each cursor (start, current and end) consists of a VDBE cursor
+**   (WindowCsrAndReg.csr) and an array of registers (starting at
+**   WindowCodeArg.reg) that always contains a copy of the peer values
+**   read from the corresponding cursor.
+**
+**   Depending on the window-frame in question, all three cursors may not
+**   be required. In this case both WindowCodeArg.csr and reg are set to
+**   0.
+*/
+struct WindowCodeArg {
+  Parse *pParse;             /* Parse context */
+  Window *pMWin;             /* First in list of functions being processed */
+  Vdbe *pVdbe;               /* VDBE object */
+  int addrGosub;             /* OP_Gosub to this address to return one row */
+  int regGosub;              /* Register used with OP_Gosub(addrGosub) */
+  int regArg;                /* First in array of accumulator registers */
+  int eDelete;               /* See above */
+  int regRowid;
+
+  WindowCsrAndReg start;
+  WindowCsrAndReg current;
+  WindowCsrAndReg end;
+};
+
+/*
+** Generate VM code to read the window frames peer values from cursor csr into
+** an array of registers starting at reg.
+*/
+static void windowReadPeerValues(
+  WindowCodeArg *p,
+  int csr,
+  int reg
+){
+  Window *pMWin = p->pMWin;
+  ExprList *pOrderBy = pMWin->pOrderBy;
+  if( pOrderBy ){
+    Vdbe *v = sqlite3GetVdbe(p->pParse);
+    ExprList *pPart = pMWin->pPartition;
+    int iColOff = pMWin->nBufferCol + (pPart ? pPart->nExpr : 0);
+    int i;
+    for(i=0; i<pOrderBy->nExpr; i++){
+      sqlite3VdbeAddOp3(v, OP_Column, csr, iColOff+i, reg+i);
+    }
+  }
+}
+
+/*
+** Generate VM code to invoke either xStep() (if bInverse is 0) or
+** xInverse (if bInverse is non-zero) for each window function in the
+** linked list starting at pMWin. Or, for built-in window functions
+** that do not use the standard function API, generate the required
+** inline VM code.
+**
+** If argument csr is greater than or equal to 0, then argument reg is
+** the first register in an array of registers guaranteed to be large
+** enough to hold the array of arguments for each function. In this case
+** the arguments are extracted from the current row of csr into the
+** array of registers before invoking OP_AggStep or OP_AggInverse
+**
+** Or, if csr is less than zero, then the array of registers at reg is
+** already populated with all columns from the current row of the sub-query.
+**
+** If argument regPartSize is non-zero, then it is a register containing the
+** number of rows in the current partition.
+*/
+static void windowAggStep(
+  WindowCodeArg *p,
+  Window *pMWin,                  /* Linked list of window functions */
+  int csr,                        /* Read arguments from this cursor */
+  int bInverse,                   /* True to invoke xInverse instead of xStep */
+  int reg                         /* Array of registers */
+){
+  Parse *pParse = p->pParse;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  Window *pWin;
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    FuncDef *pFunc = pWin->pWFunc;
+    int regArg;
+    int nArg = pWin->bExprArgs ? 0 : windowArgCount(pWin);
+    int i;
+    int addrIf = 0;
+
+    assert( bInverse==0 || pWin->eStart!=TK_UNBOUNDED );
+
+    /* All OVER clauses in the same window function aggregate step must
+    ** be the same. */
+    assert( pWin==pMWin || sqlite3WindowCompare(pParse,pWin,pMWin,0)!=1 );
+
+    for(i=0; i<nArg; i++){
+      if( i!=1 || pFunc->zName!=nth_valueName ){
+        sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+i, reg+i);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_Column, pMWin->iEphCsr, pWin->iArgCol+i, reg+i);
+      }
+    }
+    regArg = reg;
+
+    if( pWin->pFilter ){
+      int regTmp;
+      assert( ExprUseXList(pWin->pOwner) );
+      assert( pWin->bExprArgs || !nArg ||nArg==pWin->pOwner->x.pList->nExpr );
+      assert( pWin->bExprArgs || nArg  ||pWin->pOwner->x.pList==0 );
+      regTmp = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+nArg,regTmp);
+      addrIf = sqlite3VdbeAddOp3(v, OP_IfNot, regTmp, 0, 1);
+      VdbeCoverage(v);
+      sqlite3ReleaseTempReg(pParse, regTmp);
+    }
+
+    if( pMWin->regStartRowid==0
+     && (pFunc->funcFlags & SQLITE_FUNC_MINMAX)
+     && (pWin->eStart!=TK_UNBOUNDED)
+    ){
+      int addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, regArg);
+      VdbeCoverage(v);
+      if( bInverse==0 ){
+        sqlite3VdbeAddOp2(v, OP_AddImm, pWin->regApp+1, 1);
+        sqlite3VdbeAddOp2(v, OP_SCopy, regArg, pWin->regApp);
+        sqlite3VdbeAddOp3(v, OP_MakeRecord, pWin->regApp, 2, pWin->regApp+2);
+        sqlite3VdbeAddOp2(v, OP_IdxInsert, pWin->csrApp, pWin->regApp+2);
+      }else{
+        sqlite3VdbeAddOp4Int(v, OP_SeekGE, pWin->csrApp, 0, regArg, 1);
+        VdbeCoverageNeverTaken(v);
+        sqlite3VdbeAddOp1(v, OP_Delete, pWin->csrApp);
+        sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
+      }
+      sqlite3VdbeJumpHere(v, addrIsNull);
+    }else if( pWin->regApp ){
+      assert( pWin->pFilter==0 );
+      assert( pFunc->zName==nth_valueName
+           || pFunc->zName==first_valueName
+      );
+      assert( bInverse==0 || bInverse==1 );
+      sqlite3VdbeAddOp2(v, OP_AddImm, pWin->regApp+1-bInverse, 1);
+    }else if( pFunc->xSFunc!=noopStepFunc ){
+      if( pWin->bExprArgs ){
+        int iOp = sqlite3VdbeCurrentAddr(v);
+        int iEnd;
+
+        assert( ExprUseXList(pWin->pOwner) );
+        nArg = pWin->pOwner->x.pList->nExpr;
+        regArg = sqlite3GetTempRange(pParse, nArg);
+        sqlite3ExprCodeExprList(pParse, pWin->pOwner->x.pList, regArg, 0, 0);
+
+        for(iEnd=sqlite3VdbeCurrentAddr(v); iOp<iEnd; iOp++){
+          VdbeOp *pOp = sqlite3VdbeGetOp(v, iOp);
+          if( pOp->opcode==OP_Column && pOp->p1==pMWin->iEphCsr ){
+            pOp->p1 = csr;
+          }
+        }
+      }
+      if( pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){
+        CollSeq *pColl;
+        assert( nArg>0 );
+        assert( ExprUseXList(pWin->pOwner) );
+        pColl = sqlite3ExprNNCollSeq(pParse, pWin->pOwner->x.pList->a[0].pExpr);
+        sqlite3VdbeAddOp4(v, OP_CollSeq, 0,0,0, (const char*)pColl, P4_COLLSEQ);
+      }
+      sqlite3VdbeAddOp3(v, bInverse? OP_AggInverse : OP_AggStep,
+                        bInverse, regArg, pWin->regAccum);
+      sqlite3VdbeAppendP4(v, pFunc, P4_FUNCDEF);
+      sqlite3VdbeChangeP5(v, (u16)nArg);
+      if( pWin->bExprArgs ){
+        sqlite3ReleaseTempRange(pParse, regArg, nArg);
+      }
+    }
+
+    if( addrIf ) sqlite3VdbeJumpHere(v, addrIf);
+  }
+}
+
+/*
+** Values that may be passed as the second argument to windowCodeOp().
+*/
+#define WINDOW_RETURN_ROW 1
+#define WINDOW_AGGINVERSE 2
+#define WINDOW_AGGSTEP    3
+
+/*
+** Generate VM code to invoke either xValue() (bFin==0) or xFinalize()
+** (bFin==1) for each window function in the linked list starting at
+** pMWin. Or, for built-in window-functions that do not use the standard
+** API, generate the equivalent VM code.
+*/
+static void windowAggFinal(WindowCodeArg *p, int bFin){
+  Parse *pParse = p->pParse;
+  Window *pMWin = p->pMWin;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  Window *pWin;
+
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    if( pMWin->regStartRowid==0
+     && (pWin->pWFunc->funcFlags & SQLITE_FUNC_MINMAX)
+     && (pWin->eStart!=TK_UNBOUNDED)
+    ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult);
+      sqlite3VdbeAddOp1(v, OP_Last, pWin->csrApp);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_Column, pWin->csrApp, 0, pWin->regResult);
+      sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
+    }else if( pWin->regApp ){
+      assert( pMWin->regStartRowid==0 );
+    }else{
+      int nArg = windowArgCount(pWin);
+      if( bFin ){
+        sqlite3VdbeAddOp2(v, OP_AggFinal, pWin->regAccum, nArg);
+        sqlite3VdbeAppendP4(v, pWin->pWFunc, P4_FUNCDEF);
+        sqlite3VdbeAddOp2(v, OP_Copy, pWin->regAccum, pWin->regResult);
+        sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_AggValue,pWin->regAccum,nArg,pWin->regResult);
+        sqlite3VdbeAppendP4(v, pWin->pWFunc, P4_FUNCDEF);
+      }
+    }
+  }
+}
+
+/*
+** Generate code to calculate the current values of all window functions in the
+** p->pMWin list by doing a full scan of the current window frame. Store the
+** results in the Window.regResult registers, ready to return the upper
+** layer.
+*/
+static void windowFullScan(WindowCodeArg *p){
+  Window *pWin;
+  Parse *pParse = p->pParse;
+  Window *pMWin = p->pMWin;
+  Vdbe *v = p->pVdbe;
+
+  int regCRowid = 0;              /* Current rowid value */
+  int regCPeer = 0;               /* Current peer values */
+  int regRowid = 0;               /* AggStep rowid value */
+  int regPeer = 0;                /* AggStep peer values */
+
+  int nPeer;
+  int lblNext;
+  int lblBrk;
+  int addrNext;
+  int csr;
+
+  VdbeModuleComment((v, "windowFullScan begin"));
+
+  assert( pMWin!=0 );
+  csr = pMWin->csrApp;
+  nPeer = (pMWin->pOrderBy ? pMWin->pOrderBy->nExpr : 0);
+
+  lblNext = sqlite3VdbeMakeLabel(pParse);
+  lblBrk = sqlite3VdbeMakeLabel(pParse);
+
+  regCRowid = sqlite3GetTempReg(pParse);
+  regRowid = sqlite3GetTempReg(pParse);
+  if( nPeer ){
+    regCPeer = sqlite3GetTempRange(pParse, nPeer);
+    regPeer = sqlite3GetTempRange(pParse, nPeer);
+  }
+
+  sqlite3VdbeAddOp2(v, OP_Rowid, pMWin->iEphCsr, regCRowid);
+  windowReadPeerValues(p, pMWin->iEphCsr, regCPeer);
+
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
+  }
+
+  sqlite3VdbeAddOp3(v, OP_SeekGE, csr, lblBrk, pMWin->regStartRowid);
+  VdbeCoverage(v);
+  addrNext = sqlite3VdbeCurrentAddr(v);
+  sqlite3VdbeAddOp2(v, OP_Rowid, csr, regRowid);
+  sqlite3VdbeAddOp3(v, OP_Gt, pMWin->regEndRowid, lblBrk, regRowid);
+  VdbeCoverageNeverNull(v);
+
+  if( pMWin->eExclude==TK_CURRENT ){
+    sqlite3VdbeAddOp3(v, OP_Eq, regCRowid, lblNext, regRowid);
+    VdbeCoverageNeverNull(v);
+  }else if( pMWin->eExclude!=TK_NO ){
+    int addr;
+    int addrEq = 0;
+    KeyInfo *pKeyInfo = 0;
+
+    if( pMWin->pOrderBy ){
+      pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pMWin->pOrderBy, 0, 0);
+    }
+    if( pMWin->eExclude==TK_TIES ){
+      addrEq = sqlite3VdbeAddOp3(v, OP_Eq, regCRowid, 0, regRowid);
+      VdbeCoverageNeverNull(v);
+    }
+    if( pKeyInfo ){
+      windowReadPeerValues(p, csr, regPeer);
+      sqlite3VdbeAddOp3(v, OP_Compare, regPeer, regCPeer, nPeer);
+      sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
+      addr = sqlite3VdbeCurrentAddr(v)+1;
+      sqlite3VdbeAddOp3(v, OP_Jump, addr, lblNext, addr);
+      VdbeCoverageEqNe(v);
+    }else{
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, lblNext);
+    }
+    if( addrEq ) sqlite3VdbeJumpHere(v, addrEq);
+  }
+
+  windowAggStep(p, pMWin, csr, 0, p->regArg);
+
+  sqlite3VdbeResolveLabel(v, lblNext);
+  sqlite3VdbeAddOp2(v, OP_Next, csr, addrNext);
+  VdbeCoverage(v);
+  sqlite3VdbeJumpHere(v, addrNext-1);
+  sqlite3VdbeJumpHere(v, addrNext+1);
+  sqlite3ReleaseTempReg(pParse, regRowid);
+  sqlite3ReleaseTempReg(pParse, regCRowid);
+  if( nPeer ){
+    sqlite3ReleaseTempRange(pParse, regPeer, nPeer);
+    sqlite3ReleaseTempRange(pParse, regCPeer, nPeer);
+  }
+
+  windowAggFinal(p, 1);
+  VdbeModuleComment((v, "windowFullScan end"));
+}
+
+/*
+** Invoke the sub-routine at regGosub (generated by code in select.c) to
+** return the current row of Window.iEphCsr. If all window functions are
+** aggregate window functions that use the standard API, a single
+** OP_Gosub instruction is all that this routine generates. Extra VM code
+** for per-row processing is only generated for the following built-in window
+** functions:
+**
+**   nth_value()
+**   first_value()
+**   lag()
+**   lead()
+*/
+static void windowReturnOneRow(WindowCodeArg *p){
+  Window *pMWin = p->pMWin;
+  Vdbe *v = p->pVdbe;
+
+  if( pMWin->regStartRowid ){
+    windowFullScan(p);
+  }else{
+    Parse *pParse = p->pParse;
+    Window *pWin;
+
+    for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+      FuncDef *pFunc = pWin->pWFunc;
+      assert( ExprUseXList(pWin->pOwner) );
+      if( pFunc->zName==nth_valueName
+       || pFunc->zName==first_valueName
+      ){
+        int csr = pWin->csrApp;
+        int lbl = sqlite3VdbeMakeLabel(pParse);
+        int tmpReg = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult);
+
+        if( pFunc->zName==nth_valueName ){
+          sqlite3VdbeAddOp3(v, OP_Column,pMWin->iEphCsr,pWin->iArgCol+1,tmpReg);
+          windowCheckValue(pParse, tmpReg, 2);
+        }else{
+          sqlite3VdbeAddOp2(v, OP_Integer, 1, tmpReg);
+        }
+        sqlite3VdbeAddOp3(v, OP_Add, tmpReg, pWin->regApp, tmpReg);
+        sqlite3VdbeAddOp3(v, OP_Gt, pWin->regApp+1, lbl, tmpReg);
+        VdbeCoverageNeverNull(v);
+        sqlite3VdbeAddOp3(v, OP_SeekRowid, csr, 0, tmpReg);
+        VdbeCoverageNeverTaken(v);
+        sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol, pWin->regResult);
+        sqlite3VdbeResolveLabel(v, lbl);
+        sqlite3ReleaseTempReg(pParse, tmpReg);
+      }
+      else if( pFunc->zName==leadName || pFunc->zName==lagName ){
+        int nArg = pWin->pOwner->x.pList->nExpr;
+        int csr = pWin->csrApp;
+        int lbl = sqlite3VdbeMakeLabel(pParse);
+        int tmpReg = sqlite3GetTempReg(pParse);
+        int iEph = pMWin->iEphCsr;
+
+        if( nArg<3 ){
+          sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult);
+        }else{
+          sqlite3VdbeAddOp3(v, OP_Column, iEph,pWin->iArgCol+2,pWin->regResult);
+        }
+        sqlite3VdbeAddOp2(v, OP_Rowid, iEph, tmpReg);
+        if( nArg<2 ){
+          int val = (pFunc->zName==leadName ? 1 : -1);
+          sqlite3VdbeAddOp2(v, OP_AddImm, tmpReg, val);
+        }else{
+          int op = (pFunc->zName==leadName ? OP_Add : OP_Subtract);
+          int tmpReg2 = sqlite3GetTempReg(pParse);
+          sqlite3VdbeAddOp3(v, OP_Column, iEph, pWin->iArgCol+1, tmpReg2);
+          sqlite3VdbeAddOp3(v, op, tmpReg2, tmpReg, tmpReg);
+          sqlite3ReleaseTempReg(pParse, tmpReg2);
+        }
+
+        sqlite3VdbeAddOp3(v, OP_SeekRowid, csr, lbl, tmpReg);
+        VdbeCoverage(v);
+        sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol, pWin->regResult);
+        sqlite3VdbeResolveLabel(v, lbl);
+        sqlite3ReleaseTempReg(pParse, tmpReg);
+      }
+    }
+  }
+  sqlite3VdbeAddOp2(v, OP_Gosub, p->regGosub, p->addrGosub);
+}
+
+/*
+** Generate code to set the accumulator register for each window function
+** in the linked list passed as the second argument to NULL. And perform
+** any equivalent initialization required by any built-in window functions
+** in the list.
+*/
+static int windowInitAccum(Parse *pParse, Window *pMWin){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int regArg;
+  int nArg = 0;
+  Window *pWin;
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    FuncDef *pFunc = pWin->pWFunc;
+    assert( pWin->regAccum );
+    sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
+    nArg = MAX(nArg, windowArgCount(pWin));
+    if( pMWin->regStartRowid==0 ){
+      if( pFunc->zName==nth_valueName || pFunc->zName==first_valueName ){
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp);
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1);
+      }
+
+      if( (pFunc->funcFlags & SQLITE_FUNC_MINMAX) && pWin->csrApp ){
+        assert( pWin->eStart!=TK_UNBOUNDED );
+        sqlite3VdbeAddOp1(v, OP_ResetSorter, pWin->csrApp);
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1);
+      }
+    }
+  }
+  regArg = pParse->nMem+1;
+  pParse->nMem += nArg;
+  return regArg;
+}
+
+/*
+** Return true if the current frame should be cached in the ephemeral table,
+** even if there are no xInverse() calls required.
+*/
+static int windowCacheFrame(Window *pMWin){
+  Window *pWin;
+  if( pMWin->regStartRowid ) return 1;
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    FuncDef *pFunc = pWin->pWFunc;
+    if( (pFunc->zName==nth_valueName)
+     || (pFunc->zName==first_valueName)
+     || (pFunc->zName==leadName)
+     || (pFunc->zName==lagName)
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** regOld and regNew are each the first register in an array of size
+** pOrderBy->nExpr. This function generates code to compare the two
+** arrays of registers using the collation sequences and other comparison
+** parameters specified by pOrderBy.
+**
+** If the two arrays are not equal, the contents of regNew is copied to
+** regOld and control falls through. Otherwise, if the contents of the arrays
+** are equal, an OP_Goto is executed. The address of the OP_Goto is returned.
+*/
+static void windowIfNewPeer(
+  Parse *pParse,
+  ExprList *pOrderBy,
+  int regNew,                     /* First in array of new values */
+  int regOld,                     /* First in array of old values */
+  int addr                        /* Jump here */
+){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( pOrderBy ){
+    int nVal = pOrderBy->nExpr;
+    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pOrderBy, 0, 0);
+    sqlite3VdbeAddOp3(v, OP_Compare, regOld, regNew, nVal);
+    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
+    sqlite3VdbeAddOp3(v, OP_Jump,
+      sqlite3VdbeCurrentAddr(v)+1, addr, sqlite3VdbeCurrentAddr(v)+1
+    );
+    VdbeCoverageEqNe(v);
+    sqlite3VdbeAddOp3(v, OP_Copy, regNew, regOld, nVal-1);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
+  }
+}
+
+/*
+** This function is called as part of generating VM programs for RANGE
+** offset PRECEDING/FOLLOWING frame boundaries. Assuming "ASC" order for
+** the ORDER BY term in the window, and that argument op is OP_Ge, it generates
+** code equivalent to:
+**
+**   if( csr1.peerVal + regVal >= csr2.peerVal ) goto lbl;
+**
+** The value of parameter op may also be OP_Gt or OP_Le. In these cases the
+** operator in the above pseudo-code is replaced with ">" or "<=", respectively.
+**
+** If the sort-order for the ORDER BY term in the window is DESC, then the
+** comparison is reversed. Instead of adding regVal to csr1.peerVal, it is
+** subtracted. And the comparison operator is inverted to - ">=" becomes "<=",
+** ">" becomes "<", and so on. So, with DESC sort order, if the argument op
+** is OP_Ge, the generated code is equivalent to:
+**
+**   if( csr1.peerVal - regVal <= csr2.peerVal ) goto lbl;
+**
+** A special type of arithmetic is used such that if csr1.peerVal is not
+** a numeric type (real or integer), then the result of the addition
+** or subtraction is a a copy of csr1.peerVal.
+*/
+static void windowCodeRangeTest(
+  WindowCodeArg *p,
+  int op,                         /* OP_Ge, OP_Gt, or OP_Le */
+  int csr1,                       /* Cursor number for cursor 1 */
+  int regVal,                     /* Register containing non-negative number */
+  int csr2,                       /* Cursor number for cursor 2 */
+  int lbl                         /* Jump destination if condition is true */
+){
+  Parse *pParse = p->pParse;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  ExprList *pOrderBy = p->pMWin->pOrderBy;  /* ORDER BY clause for window */
+  int reg1 = sqlite3GetTempReg(pParse);     /* Reg. for csr1.peerVal+regVal */
+  int reg2 = sqlite3GetTempReg(pParse);     /* Reg. for csr2.peerVal */
+  int regString = ++pParse->nMem;           /* Reg. for constant value '' */
+  int arith = OP_Add;                       /* OP_Add or OP_Subtract */
+  int addrGe;                               /* Jump destination */
+  int addrDone = sqlite3VdbeMakeLabel(pParse);   /* Address past OP_Ge */
+  CollSeq *pColl;
+
+  /* Read the peer-value from each cursor into a register */
+  windowReadPeerValues(p, csr1, reg1);
+  windowReadPeerValues(p, csr2, reg2);
+
+  assert( op==OP_Ge || op==OP_Gt || op==OP_Le );
+  assert( pOrderBy && pOrderBy->nExpr==1 );
+  if( pOrderBy->a[0].fg.sortFlags & KEYINFO_ORDER_DESC ){
+    switch( op ){
+      case OP_Ge: op = OP_Le; break;
+      case OP_Gt: op = OP_Lt; break;
+      default: assert( op==OP_Le ); op = OP_Ge; break;
+    }
+    arith = OP_Subtract;
+  }
+
+  VdbeModuleComment((v, "CodeRangeTest: if( R%d %s R%d %s R%d ) goto lbl",
+      reg1, (arith==OP_Add ? "+" : "-"), regVal,
+      ((op==OP_Ge) ? ">=" : (op==OP_Le) ? "<=" : (op==OP_Gt) ? ">" : "<"), reg2
+  ));
+
+  /* If the BIGNULL flag is set for the ORDER BY, then it is required to
+  ** consider NULL values to be larger than all other values, instead of
+  ** the usual smaller. The VDBE opcodes OP_Ge and so on do not handle this
+  ** (and adding that capability causes a performance regression), so
+  ** instead if the BIGNULL flag is set then cases where either reg1 or
+  ** reg2 are NULL are handled separately in the following block. The code
+  ** generated is equivalent to:
+  **
+  **   if( reg1 IS NULL ){
+  **     if( op==OP_Ge ) goto lbl;
+  **     if( op==OP_Gt && reg2 IS NOT NULL ) goto lbl;
+  **     if( op==OP_Le && reg2 IS NULL ) goto lbl;
+  **   }else if( reg2 IS NULL ){
+  **     if( op==OP_Le ) goto lbl;
+  **   }
+  **
+  ** Additionally, if either reg1 or reg2 are NULL but the jump to lbl is
+  ** not taken, control jumps over the comparison operator coded below this
+  ** block.  */
+  if( pOrderBy->a[0].fg.sortFlags & KEYINFO_ORDER_BIGNULL ){
+    /* This block runs if reg1 contains a NULL. */
+    int addr = sqlite3VdbeAddOp1(v, OP_NotNull, reg1); VdbeCoverage(v);
+    switch( op ){
+      case OP_Ge:
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, lbl);
+        break;
+      case OP_Gt:
+        sqlite3VdbeAddOp2(v, OP_NotNull, reg2, lbl);
+        VdbeCoverage(v);
+        break;
+      case OP_Le:
+        sqlite3VdbeAddOp2(v, OP_IsNull, reg2, lbl);
+        VdbeCoverage(v);
+        break;
+      default: assert( op==OP_Lt ); /* no-op */ break;
+    }
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrDone);
+
+    /* This block runs if reg1 is not NULL, but reg2 is. */
+    sqlite3VdbeJumpHere(v, addr);
+    sqlite3VdbeAddOp2(v, OP_IsNull, reg2,
+                      (op==OP_Gt || op==OP_Ge) ? addrDone : lbl);
+    VdbeCoverage(v);
+  }
+
+  /* Register reg1 currently contains csr1.peerVal (the peer-value from csr1).
+  ** This block adds (or subtracts for DESC) the numeric value in regVal
+  ** from it. Or, if reg1 is not numeric (it is a NULL, a text value or a blob),
+  ** then leave reg1 as it is. In pseudo-code, this is implemented as:
+  **
+  **   if( reg1>='' ) goto addrGe;
+  **   reg1 = reg1 +/- regVal
+  **   addrGe:
+  **
+  ** Since all strings and blobs are greater-than-or-equal-to an empty string,
+  ** the add/subtract is skipped for these, as required. If reg1 is a NULL,
+  ** then the arithmetic is performed, but since adding or subtracting from
+  ** NULL is always NULL anyway, this case is handled as required too.  */
+  sqlite3VdbeAddOp4(v, OP_String8, 0, regString, 0, "", P4_STATIC);
+  addrGe = sqlite3VdbeAddOp3(v, OP_Ge, regString, 0, reg1);
+  VdbeCoverage(v);
+  if( (op==OP_Ge && arith==OP_Add) || (op==OP_Le && arith==OP_Subtract) ){
+    sqlite3VdbeAddOp3(v, op, reg2, lbl, reg1); VdbeCoverage(v);
+  }
+  sqlite3VdbeAddOp3(v, arith, regVal, reg1, reg1);
+  sqlite3VdbeJumpHere(v, addrGe);
+
+  /* Compare registers reg2 and reg1, taking the jump if required. Note that
+  ** control skips over this test if the BIGNULL flag is set and either
+  ** reg1 or reg2 contain a NULL value.  */
+  sqlite3VdbeAddOp3(v, op, reg2, lbl, reg1); VdbeCoverage(v);
+  pColl = sqlite3ExprNNCollSeq(pParse, pOrderBy->a[0].pExpr);
+  sqlite3VdbeAppendP4(v, (void*)pColl, P4_COLLSEQ);
+  sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
+  sqlite3VdbeResolveLabel(v, addrDone);
+
+  assert( op==OP_Ge || op==OP_Gt || op==OP_Lt || op==OP_Le );
+  testcase(op==OP_Ge); VdbeCoverageIf(v, op==OP_Ge);
+  testcase(op==OP_Lt); VdbeCoverageIf(v, op==OP_Lt);
+  testcase(op==OP_Le); VdbeCoverageIf(v, op==OP_Le);
+  testcase(op==OP_Gt); VdbeCoverageIf(v, op==OP_Gt);
+  sqlite3ReleaseTempReg(pParse, reg1);
+  sqlite3ReleaseTempReg(pParse, reg2);
+
+  VdbeModuleComment((v, "CodeRangeTest: end"));
+}
+
+/*
+** Helper function for sqlite3WindowCodeStep(). Each call to this function
+** generates VM code for a single RETURN_ROW, AGGSTEP or AGGINVERSE
+** operation. Refer to the header comment for sqlite3WindowCodeStep() for
+** details.
+*/
+static int windowCodeOp(
+ WindowCodeArg *p,                /* Context object */
+ int op,                          /* WINDOW_RETURN_ROW, AGGSTEP or AGGINVERSE */
+ int regCountdown,                /* Register for OP_IfPos countdown */
+ int jumpOnEof                    /* Jump here if stepped cursor reaches EOF */
+){
+  int csr, reg;
+  Parse *pParse = p->pParse;
+  Window *pMWin = p->pMWin;
+  int ret = 0;
+  Vdbe *v = p->pVdbe;
+  int addrContinue = 0;
+  int bPeer = (pMWin->eFrmType!=TK_ROWS);
+
+  int lblDone = sqlite3VdbeMakeLabel(pParse);
+  int addrNextRange = 0;
+
+  /* Special case - WINDOW_AGGINVERSE is always a no-op if the frame
+  ** starts with UNBOUNDED PRECEDING. */
+  if( op==WINDOW_AGGINVERSE && pMWin->eStart==TK_UNBOUNDED ){
+    assert( regCountdown==0 && jumpOnEof==0 );
+    return 0;
+  }
+
+  if( regCountdown>0 ){
+    if( pMWin->eFrmType==TK_RANGE ){
+      addrNextRange = sqlite3VdbeCurrentAddr(v);
+      assert( op==WINDOW_AGGINVERSE || op==WINDOW_AGGSTEP );
+      if( op==WINDOW_AGGINVERSE ){
+        if( pMWin->eStart==TK_FOLLOWING ){
+          windowCodeRangeTest(
+              p, OP_Le, p->current.csr, regCountdown, p->start.csr, lblDone
+          );
+        }else{
+          windowCodeRangeTest(
+              p, OP_Ge, p->start.csr, regCountdown, p->current.csr, lblDone
+          );
+        }
+      }else{
+        windowCodeRangeTest(
+            p, OP_Gt, p->end.csr, regCountdown, p->current.csr, lblDone
+        );
+      }
+    }else{
+      sqlite3VdbeAddOp3(v, OP_IfPos, regCountdown, lblDone, 1);
+      VdbeCoverage(v);
+    }
+  }
+
+  if( op==WINDOW_RETURN_ROW && pMWin->regStartRowid==0 ){
+    windowAggFinal(p, 0);
+  }
+  addrContinue = sqlite3VdbeCurrentAddr(v);
+
+  /* If this is a (RANGE BETWEEN a FOLLOWING AND b FOLLOWING) or
+  ** (RANGE BETWEEN b PRECEDING AND a PRECEDING) frame, ensure the
+  ** start cursor does not advance past the end cursor within the
+  ** temporary table. It otherwise might, if (a>b). Also ensure that,
+  ** if the input cursor is still finding new rows, that the end
+  ** cursor does not go past it to EOF. */
+  if( pMWin->eStart==pMWin->eEnd && regCountdown
+   && pMWin->eFrmType==TK_RANGE
+  ){
+    int regRowid1 = sqlite3GetTempReg(pParse);
+    int regRowid2 = sqlite3GetTempReg(pParse);
+    if( op==WINDOW_AGGINVERSE ){
+      sqlite3VdbeAddOp2(v, OP_Rowid, p->start.csr, regRowid1);
+      sqlite3VdbeAddOp2(v, OP_Rowid, p->end.csr, regRowid2);
+      sqlite3VdbeAddOp3(v, OP_Ge, regRowid2, lblDone, regRowid1);
+      VdbeCoverage(v);
+    }else if( p->regRowid ){
+      sqlite3VdbeAddOp2(v, OP_Rowid, p->end.csr, regRowid1);
+      sqlite3VdbeAddOp3(v, OP_Ge, p->regRowid, lblDone, regRowid1);
+      VdbeCoverageNeverNull(v);
+    }
+    sqlite3ReleaseTempReg(pParse, regRowid1);
+    sqlite3ReleaseTempReg(pParse, regRowid2);
+    assert( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_FOLLOWING );
+  }
+
+  switch( op ){
+    case WINDOW_RETURN_ROW:
+      csr = p->current.csr;
+      reg = p->current.reg;
+      windowReturnOneRow(p);
+      break;
+
+    case WINDOW_AGGINVERSE:
+      csr = p->start.csr;
+      reg = p->start.reg;
+      if( pMWin->regStartRowid ){
+        assert( pMWin->regEndRowid );
+        sqlite3VdbeAddOp2(v, OP_AddImm, pMWin->regStartRowid, 1);
+      }else{
+        windowAggStep(p, pMWin, csr, 1, p->regArg);
+      }
+      break;
+
+    default:
+      assert( op==WINDOW_AGGSTEP );
+      csr = p->end.csr;
+      reg = p->end.reg;
+      if( pMWin->regStartRowid ){
+        assert( pMWin->regEndRowid );
+        sqlite3VdbeAddOp2(v, OP_AddImm, pMWin->regEndRowid, 1);
+      }else{
+        windowAggStep(p, pMWin, csr, 0, p->regArg);
+      }
+      break;
+  }
+
+  if( op==p->eDelete ){
+    sqlite3VdbeAddOp1(v, OP_Delete, csr);
+    sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION);
+  }
+
+  if( jumpOnEof ){
+    sqlite3VdbeAddOp2(v, OP_Next, csr, sqlite3VdbeCurrentAddr(v)+2);
+    VdbeCoverage(v);
+    ret = sqlite3VdbeAddOp0(v, OP_Goto);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Next, csr, sqlite3VdbeCurrentAddr(v)+1+bPeer);
+    VdbeCoverage(v);
+    if( bPeer ){
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, lblDone);
+    }
+  }
+
+  if( bPeer ){
+    int nReg = (pMWin->pOrderBy ? pMWin->pOrderBy->nExpr : 0);
+    int regTmp = (nReg ? sqlite3GetTempRange(pParse, nReg) : 0);
+    windowReadPeerValues(p, csr, regTmp);
+    windowIfNewPeer(pParse, pMWin->pOrderBy, regTmp, reg, addrContinue);
+    sqlite3ReleaseTempRange(pParse, regTmp, nReg);
+  }
+
+  if( addrNextRange ){
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrNextRange);
+  }
+  sqlite3VdbeResolveLabel(v, lblDone);
+  return ret;
+}
+
+
+/*
+** Allocate and return a duplicate of the Window object indicated by the
+** third argument. Set the Window.pOwner field of the new object to
+** pOwner.
+*/
+SQLITE_PRIVATE Window *sqlite3WindowDup(sqlite3 *db, Expr *pOwner, Window *p){
+  Window *pNew = 0;
+  if( ALWAYS(p) ){
+    pNew = sqlite3DbMallocZero(db, sizeof(Window));
+    if( pNew ){
+      pNew->zName = sqlite3DbStrDup(db, p->zName);
+      pNew->zBase = sqlite3DbStrDup(db, p->zBase);
+      pNew->pFilter = sqlite3ExprDup(db, p->pFilter, 0);
+      pNew->pWFunc = p->pWFunc;
+      pNew->pPartition = sqlite3ExprListDup(db, p->pPartition, 0);
+      pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy, 0);
+      pNew->eFrmType = p->eFrmType;
+      pNew->eEnd = p->eEnd;
+      pNew->eStart = p->eStart;
+      pNew->eExclude = p->eExclude;
+      pNew->regResult = p->regResult;
+      pNew->regAccum = p->regAccum;
+      pNew->iArgCol = p->iArgCol;
+      pNew->iEphCsr = p->iEphCsr;
+      pNew->bExprArgs = p->bExprArgs;
+      pNew->pStart = sqlite3ExprDup(db, p->pStart, 0);
+      pNew->pEnd = sqlite3ExprDup(db, p->pEnd, 0);
+      pNew->pOwner = pOwner;
+      pNew->bImplicitFrame = p->bImplicitFrame;
+    }
+  }
+  return pNew;
+}
+
+/*
+** Return a copy of the linked list of Window objects passed as the
+** second argument.
+*/
+SQLITE_PRIVATE Window *sqlite3WindowListDup(sqlite3 *db, Window *p){
+  Window *pWin;
+  Window *pRet = 0;
+  Window **pp = &pRet;
+
+  for(pWin=p; pWin; pWin=pWin->pNextWin){
+    *pp = sqlite3WindowDup(db, 0, pWin);
+    if( *pp==0 ) break;
+    pp = &((*pp)->pNextWin);
+  }
+
+  return pRet;
+}
+
+/*
+** Return true if it can be determined at compile time that expression
+** pExpr evaluates to a value that, when cast to an integer, is greater
+** than zero. False otherwise.
+**
+** If an OOM error occurs, this function sets the Parse.db.mallocFailed
+** flag and returns zero.
+*/
+static int windowExprGtZero(Parse *pParse, Expr *pExpr){
+  int ret = 0;
+  sqlite3 *db = pParse->db;
+  sqlite3_value *pVal = 0;
+  sqlite3ValueFromExpr(db, pExpr, db->enc, SQLITE_AFF_NUMERIC, &pVal);
+  if( pVal && sqlite3_value_int(pVal)>0 ){
+    ret = 1;
+  }
+  sqlite3ValueFree(pVal);
+  return ret;
+}
+
+/*
+** sqlite3WhereBegin() has already been called for the SELECT statement
+** passed as the second argument when this function is invoked. It generates
+** code to populate the Window.regResult register for each window function
+** and invoke the sub-routine at instruction addrGosub once for each row.
+** sqlite3WhereEnd() is always called before returning.
+**
+** This function handles several different types of window frames, which
+** require slightly different processing. The following pseudo code is
+** used to implement window frames of the form:
+**
+**   ROWS BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING
+**
+** Other window frame types use variants of the following:
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**
+**       if( first row of partition ){
+**         // Rewind three cursors, all open on the eph table.
+**         Rewind(csrEnd);
+**         Rewind(csrStart);
+**         Rewind(csrCurrent);
+**
+**         regEnd = <expr2>          // FOLLOWING expression
+**         regStart = <expr1>        // PRECEDING expression
+**       }else{
+**         // First time this branch is taken, the eph table contains two
+**         // rows. The first row in the partition, which all three cursors
+**         // currently point to, and the following row.
+**         AGGSTEP
+**         if( (regEnd--)<=0 ){
+**           RETURN_ROW
+**           if( (regStart--)<=0 ){
+**             AGGINVERSE
+**           }
+**         }
+**       }
+**     }
+**     flush:
+**       AGGSTEP
+**       while( 1 ){
+**         RETURN ROW
+**         if( csrCurrent is EOF ) break;
+**         if( (regStart--)<=0 ){
+**           AggInverse(csrStart)
+**           Next(csrStart)
+**         }
+**       }
+**
+** The pseudo-code above uses the following shorthand:
+**
+**   AGGSTEP:    invoke the aggregate xStep() function for each window function
+**               with arguments read from the current row of cursor csrEnd, then
+**               step cursor csrEnd forward one row (i.e. sqlite3BtreeNext()).
+**
+**   RETURN_ROW: return a row to the caller based on the contents of the
+**               current row of csrCurrent and the current state of all
+**               aggregates. Then step cursor csrCurrent forward one row.
+**
+**   AGGINVERSE: invoke the aggregate xInverse() function for each window
+**               functions with arguments read from the current row of cursor
+**               csrStart. Then step csrStart forward one row.
+**
+** There are two other ROWS window frames that are handled significantly
+** differently from the above - "BETWEEN <expr> PRECEDING AND <expr> PRECEDING"
+** and "BETWEEN <expr> FOLLOWING AND <expr> FOLLOWING". These are special
+** cases because they change the order in which the three cursors (csrStart,
+** csrCurrent and csrEnd) iterate through the ephemeral table. Cases that
+** use UNBOUNDED or CURRENT ROW are much simpler variations on one of these
+** three.
+**
+**   ROWS BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**       if( first row of partition ){
+**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**         regEnd = <expr2>
+**         regStart = <expr1>
+**       }else{
+**         if( (regEnd--)<=0 ){
+**           AGGSTEP
+**         }
+**         RETURN_ROW
+**         if( (regStart--)<=0 ){
+**           AGGINVERSE
+**         }
+**       }
+**     }
+**     flush:
+**       if( (regEnd--)<=0 ){
+**         AGGSTEP
+**       }
+**       RETURN_ROW
+**
+**
+**   ROWS BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**     if( new partition ){
+**       Gosub flush
+**     }
+**     Insert new row into eph table.
+**     if( first row of partition ){
+**       Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**       regEnd = <expr2>
+**       regStart = regEnd - <expr1>
+**     }else{
+**       AGGSTEP
+**       if( (regEnd--)<=0 ){
+**         RETURN_ROW
+**       }
+**       if( (regStart--)<=0 ){
+**         AGGINVERSE
+**       }
+**     }
+**   }
+**   flush:
+**     AGGSTEP
+**     while( 1 ){
+**       if( (regEnd--)<=0 ){
+**         RETURN_ROW
+**         if( eof ) break;
+**       }
+**       if( (regStart--)<=0 ){
+**         AGGINVERSE
+**         if( eof ) break
+**       }
+**     }
+**     while( !eof csrCurrent ){
+**       RETURN_ROW
+**     }
+**
+** For the most part, the patterns above are adapted to support UNBOUNDED by
+** assuming that it is equivalent to "infinity PRECEDING/FOLLOWING" and
+** CURRENT ROW by assuming that it is equivalent to "0 PRECEDING/FOLLOWING".
+** This is optimized of course - branches that will never be taken and
+** conditions that are always true are omitted from the VM code. The only
+** exceptional case is:
+**
+**   ROWS BETWEEN <expr1> FOLLOWING AND UNBOUNDED FOLLOWING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**     if( new partition ){
+**       Gosub flush
+**     }
+**     Insert new row into eph table.
+**     if( first row of partition ){
+**       Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**       regStart = <expr1>
+**     }else{
+**       AGGSTEP
+**     }
+**   }
+**   flush:
+**     AGGSTEP
+**     while( 1 ){
+**       if( (regStart--)<=0 ){
+**         AGGINVERSE
+**         if( eof ) break
+**       }
+**       RETURN_ROW
+**     }
+**     while( !eof csrCurrent ){
+**       RETURN_ROW
+**     }
+**
+** Also requiring special handling are the cases:
+**
+**   ROWS BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING
+**   ROWS BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING
+**
+** when (expr1 < expr2). This is detected at runtime, not by this function.
+** To handle this case, the pseudo-code programs depicted above are modified
+** slightly to be:
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**     if( new partition ){
+**       Gosub flush
+**     }
+**     Insert new row into eph table.
+**     if( first row of partition ){
+**       Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**       regEnd = <expr2>
+**       regStart = <expr1>
+**       if( regEnd < regStart ){
+**         RETURN_ROW
+**         delete eph table contents
+**         continue
+**       }
+**     ...
+**
+** The new "continue" statement in the above jumps to the next iteration
+** of the outer loop - the one started by sqlite3WhereBegin().
+**
+** The various GROUPS cases are implemented using the same patterns as
+** ROWS. The VM code is modified slightly so that:
+**
+**   1. The else branch in the main loop is only taken if the row just
+**      added to the ephemeral table is the start of a new group. In
+**      other words, it becomes:
+**
+**         ... loop started by sqlite3WhereBegin() ...
+**         if( new partition ){
+**           Gosub flush
+**         }
+**         Insert new row into eph table.
+**         if( first row of partition ){
+**           Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**           regEnd = <expr2>
+**           regStart = <expr1>
+**         }else if( new group ){
+**           ...
+**         }
+**       }
+**
+**   2. Instead of processing a single row, each RETURN_ROW, AGGSTEP or
+**      AGGINVERSE step processes the current row of the relevant cursor and
+**      all subsequent rows belonging to the same group.
+**
+** RANGE window frames are a little different again. As for GROUPS, the
+** main loop runs once per group only. And RETURN_ROW, AGGSTEP and AGGINVERSE
+** deal in groups instead of rows. As for ROWS and GROUPS, there are three
+** basic cases:
+**
+**   RANGE BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**       if( first row of partition ){
+**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**         regEnd = <expr2>
+**         regStart = <expr1>
+**       }else{
+**         AGGSTEP
+**         while( (csrCurrent.key + regEnd) < csrEnd.key ){
+**           RETURN_ROW
+**           while( csrStart.key + regStart) < csrCurrent.key ){
+**             AGGINVERSE
+**           }
+**         }
+**       }
+**     }
+**     flush:
+**       AGGSTEP
+**       while( 1 ){
+**         RETURN ROW
+**         if( csrCurrent is EOF ) break;
+**           while( csrStart.key + regStart) < csrCurrent.key ){
+**             AGGINVERSE
+**           }
+**         }
+**       }
+**
+** In the above notation, "csr.key" means the current value of the ORDER BY
+** expression (there is only ever 1 for a RANGE that uses an <expr> FOLLOWING
+** or <expr PRECEDING) read from cursor csr.
+**
+**   RANGE BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**       if( first row of partition ){
+**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**         regEnd = <expr2>
+**         regStart = <expr1>
+**       }else{
+**         while( (csrEnd.key + regEnd) <= csrCurrent.key ){
+**           AGGSTEP
+**         }
+**         while( (csrStart.key + regStart) < csrCurrent.key ){
+**           AGGINVERSE
+**         }
+**         RETURN_ROW
+**       }
+**     }
+**     flush:
+**       while( (csrEnd.key + regEnd) <= csrCurrent.key ){
+**         AGGSTEP
+**       }
+**       while( (csrStart.key + regStart) < csrCurrent.key ){
+**         AGGINVERSE
+**       }
+**       RETURN_ROW
+**
+**   RANGE BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**       if( first row of partition ){
+**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**         regEnd = <expr2>
+**         regStart = <expr1>
+**       }else{
+**         AGGSTEP
+**         while( (csrCurrent.key + regEnd) < csrEnd.key ){
+**           while( (csrCurrent.key + regStart) > csrStart.key ){
+**             AGGINVERSE
+**           }
+**           RETURN_ROW
+**         }
+**       }
+**     }
+**     flush:
+**       AGGSTEP
+**       while( 1 ){
+**         while( (csrCurrent.key + regStart) > csrStart.key ){
+**           AGGINVERSE
+**           if( eof ) break "while( 1 )" loop.
+**         }
+**         RETURN_ROW
+**       }
+**       while( !eof csrCurrent ){
+**         RETURN_ROW
+**       }
+**
+** The text above leaves out many details. Refer to the code and comments
+** below for a more complete picture.
+*/
+SQLITE_PRIVATE void sqlite3WindowCodeStep(
+  Parse *pParse,                  /* Parse context */
+  Select *p,                      /* Rewritten SELECT statement */
+  WhereInfo *pWInfo,              /* Context returned by sqlite3WhereBegin() */
+  int regGosub,                   /* Register for OP_Gosub */
+  int addrGosub                   /* OP_Gosub here to return each row */
+){
+  Window *pMWin = p->pWin;
+  ExprList *pOrderBy = pMWin->pOrderBy;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int csrWrite;                   /* Cursor used to write to eph. table */
+  int csrInput = p->pSrc->a[0].iCursor;     /* Cursor of sub-select */
+  int nInput = p->pSrc->a[0].pSTab->nCol;   /* Number of cols returned by sub */
+  int iInput;                               /* To iterate through sub cols */
+  int addrNe;                     /* Address of OP_Ne */
+  int addrGosubFlush = 0;         /* Address of OP_Gosub to flush: */
+  int addrInteger = 0;            /* Address of OP_Integer */
+  int addrEmpty;                  /* Address of OP_Rewind in flush: */
+  int regNew;                     /* Array of registers holding new input row */
+  int regRecord;                  /* regNew array in record form */
+  int regNewPeer = 0;             /* Peer values for new row (part of regNew) */
+  int regPeer = 0;                /* Peer values for current row */
+  int regFlushPart = 0;           /* Register for "Gosub flush_partition" */
+  WindowCodeArg s;                /* Context object for sub-routines */
+  int lblWhereEnd;                /* Label just before sqlite3WhereEnd() code */
+  int regStart = 0;               /* Value of <expr> PRECEDING */
+  int regEnd = 0;                 /* Value of <expr> FOLLOWING */
+
+  assert( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_CURRENT
+       || pMWin->eStart==TK_FOLLOWING || pMWin->eStart==TK_UNBOUNDED
+  );
+  assert( pMWin->eEnd==TK_FOLLOWING || pMWin->eEnd==TK_CURRENT
+       || pMWin->eEnd==TK_UNBOUNDED || pMWin->eEnd==TK_PRECEDING
+  );
+  assert( pMWin->eExclude==0 || pMWin->eExclude==TK_CURRENT
+       || pMWin->eExclude==TK_GROUP || pMWin->eExclude==TK_TIES
+       || pMWin->eExclude==TK_NO
+  );
+
+  lblWhereEnd = sqlite3VdbeMakeLabel(pParse);
+
+  /* Fill in the context object */
+  memset(&s, 0, sizeof(WindowCodeArg));
+  s.pParse = pParse;
+  s.pMWin = pMWin;
+  s.pVdbe = v;
+  s.regGosub = regGosub;
+  s.addrGosub = addrGosub;
+  s.current.csr = pMWin->iEphCsr;
+  csrWrite = s.current.csr+1;
+  s.start.csr = s.current.csr+2;
+  s.end.csr = s.current.csr+3;
+
+  /* Figure out when rows may be deleted from the ephemeral table. There
+  ** are four options - they may never be deleted (eDelete==0), they may
+  ** be deleted as soon as they are no longer part of the window frame
+  ** (eDelete==WINDOW_AGGINVERSE), they may be deleted as after the row
+  ** has been returned to the caller (WINDOW_RETURN_ROW), or they may
+  ** be deleted after they enter the frame (WINDOW_AGGSTEP). */
+  switch( pMWin->eStart ){
+    case TK_FOLLOWING:
+      if( pMWin->eFrmType!=TK_RANGE
+       && windowExprGtZero(pParse, pMWin->pStart)
+      ){
+        s.eDelete = WINDOW_RETURN_ROW;
+      }
+      break;
+    case TK_UNBOUNDED:
+      if( windowCacheFrame(pMWin)==0 ){
+        if( pMWin->eEnd==TK_PRECEDING ){
+          if( pMWin->eFrmType!=TK_RANGE
+           && windowExprGtZero(pParse, pMWin->pEnd)
+          ){
+            s.eDelete = WINDOW_AGGSTEP;
+          }
+        }else{
+          s.eDelete = WINDOW_RETURN_ROW;
+        }
+      }
+      break;
+    default:
+      s.eDelete = WINDOW_AGGINVERSE;
+      break;
+  }
+
+  /* Allocate registers for the array of values from the sub-query, the
+  ** same values in record form, and the rowid used to insert said record
+  ** into the ephemeral table.  */
+  regNew = pParse->nMem+1;
+  pParse->nMem += nInput;
+  regRecord = ++pParse->nMem;
+  s.regRowid = ++pParse->nMem;
+
+  /* If the window frame contains an "<expr> PRECEDING" or "<expr> FOLLOWING"
+  ** clause, allocate registers to store the results of evaluating each
+  ** <expr>.  */
+  if( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_FOLLOWING ){
+    regStart = ++pParse->nMem;
+  }
+  if( pMWin->eEnd==TK_PRECEDING || pMWin->eEnd==TK_FOLLOWING ){
+    regEnd = ++pParse->nMem;
+  }
+
+  /* If this is not a "ROWS BETWEEN ..." frame, then allocate arrays of
+  ** registers to store copies of the ORDER BY expressions (peer values)
+  ** for the main loop, and for each cursor (start, current and end). */
+  if( pMWin->eFrmType!=TK_ROWS ){
+    int nPeer = (pOrderBy ? pOrderBy->nExpr : 0);
+    regNewPeer = regNew + pMWin->nBufferCol;
+    if( pMWin->pPartition ) regNewPeer += pMWin->pPartition->nExpr;
+    regPeer = pParse->nMem+1;       pParse->nMem += nPeer;
+    s.start.reg = pParse->nMem+1;   pParse->nMem += nPeer;
+    s.current.reg = pParse->nMem+1; pParse->nMem += nPeer;
+    s.end.reg = pParse->nMem+1;     pParse->nMem += nPeer;
+  }
+
+  /* Load the column values for the row returned by the sub-select
+  ** into an array of registers starting at regNew. Assemble them into
+  ** a record in register regRecord. */
+  for(iInput=0; iInput<nInput; iInput++){
+    sqlite3VdbeAddOp3(v, OP_Column, csrInput, iInput, regNew+iInput);
+  }
+  sqlite3VdbeAddOp3(v, OP_MakeRecord, regNew, nInput, regRecord);
+
+  /* An input row has just been read into an array of registers starting
+  ** at regNew. If the window has a PARTITION clause, this block generates
+  ** VM code to check if the input row is the start of a new partition.
+  ** If so, it does an OP_Gosub to an address to be filled in later. The
+  ** address of the OP_Gosub is stored in local variable addrGosubFlush. */
+  if( pMWin->pPartition ){
+    int addr;
+    ExprList *pPart = pMWin->pPartition;
+    int nPart = pPart->nExpr;
+    int regNewPart = regNew + pMWin->nBufferCol;
+    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);
+
+    regFlushPart = ++pParse->nMem;
+    addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart, nPart);
+    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
+    sqlite3VdbeAddOp3(v, OP_Jump, addr+2, addr+4, addr+2);
+    VdbeCoverageEqNe(v);
+    addrGosubFlush = sqlite3VdbeAddOp1(v, OP_Gosub, regFlushPart);
+    VdbeComment((v, "call flush_partition"));
+    sqlite3VdbeAddOp3(v, OP_Copy, regNewPart, pMWin->regPart, nPart-1);
+  }
+
+  /* Insert the new row into the ephemeral table */
+  sqlite3VdbeAddOp2(v, OP_NewRowid, csrWrite, s.regRowid);
+  sqlite3VdbeAddOp3(v, OP_Insert, csrWrite, regRecord, s.regRowid);
+  addrNe = sqlite3VdbeAddOp3(v, OP_Ne, pMWin->regOne, 0, s.regRowid);
+  VdbeCoverageNeverNull(v);
+
+  /* This block is run for the first row of each partition */
+  s.regArg = windowInitAccum(pParse, pMWin);
+
+  if( regStart ){
+    sqlite3ExprCode(pParse, pMWin->pStart, regStart);
+    windowCheckValue(pParse, regStart, 0 + (pMWin->eFrmType==TK_RANGE?3:0));
+  }
+  if( regEnd ){
+    sqlite3ExprCode(pParse, pMWin->pEnd, regEnd);
+    windowCheckValue(pParse, regEnd, 1 + (pMWin->eFrmType==TK_RANGE?3:0));
+  }
+
+  if( pMWin->eFrmType!=TK_RANGE && pMWin->eStart==pMWin->eEnd && regStart ){
+    int op = ((pMWin->eStart==TK_FOLLOWING) ? OP_Ge : OP_Le);
+    int addrGe = sqlite3VdbeAddOp3(v, op, regStart, 0, regEnd);
+    VdbeCoverageNeverNullIf(v, op==OP_Ge); /* NeverNull because bound <expr> */
+    VdbeCoverageNeverNullIf(v, op==OP_Le); /*   values previously checked */
+    windowAggFinal(&s, 0);
+    sqlite3VdbeAddOp1(v, OP_Rewind, s.current.csr);
+    windowReturnOneRow(&s);
+    sqlite3VdbeAddOp1(v, OP_ResetSorter, s.current.csr);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, lblWhereEnd);
+    sqlite3VdbeJumpHere(v, addrGe);
+  }
+  if( pMWin->eStart==TK_FOLLOWING && pMWin->eFrmType!=TK_RANGE && regEnd ){
+    assert( pMWin->eEnd==TK_FOLLOWING );
+    sqlite3VdbeAddOp3(v, OP_Subtract, regStart, regEnd, regStart);
+  }
+
+  if( pMWin->eStart!=TK_UNBOUNDED ){
+    sqlite3VdbeAddOp1(v, OP_Rewind, s.start.csr);
+  }
+  sqlite3VdbeAddOp1(v, OP_Rewind, s.current.csr);
+  sqlite3VdbeAddOp1(v, OP_Rewind, s.end.csr);
+  if( regPeer && pOrderBy ){
+    sqlite3VdbeAddOp3(v, OP_Copy, regNewPeer, regPeer, pOrderBy->nExpr-1);
+    sqlite3VdbeAddOp3(v, OP_Copy, regPeer, s.start.reg, pOrderBy->nExpr-1);
+    sqlite3VdbeAddOp3(v, OP_Copy, regPeer, s.current.reg, pOrderBy->nExpr-1);
+    sqlite3VdbeAddOp3(v, OP_Copy, regPeer, s.end.reg, pOrderBy->nExpr-1);
+  }
+
+  sqlite3VdbeAddOp2(v, OP_Goto, 0, lblWhereEnd);
+
+  sqlite3VdbeJumpHere(v, addrNe);
+
+  /* Beginning of the block executed for the second and subsequent rows. */
+  if( regPeer ){
+    windowIfNewPeer(pParse, pOrderBy, regNewPeer, regPeer, lblWhereEnd);
+  }
+  if( pMWin->eStart==TK_FOLLOWING ){
+    windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0);
+    if( pMWin->eEnd!=TK_UNBOUNDED ){
+      if( pMWin->eFrmType==TK_RANGE ){
+        int lbl = sqlite3VdbeMakeLabel(pParse);
+        int addrNext = sqlite3VdbeCurrentAddr(v);
+        windowCodeRangeTest(&s, OP_Ge, s.current.csr, regEnd, s.end.csr, lbl);
+        windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+        windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, addrNext);
+        sqlite3VdbeResolveLabel(v, lbl);
+      }else{
+        windowCodeOp(&s, WINDOW_RETURN_ROW, regEnd, 0);
+        windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+      }
+    }
+  }else
+  if( pMWin->eEnd==TK_PRECEDING ){
+    int bRPS = (pMWin->eStart==TK_PRECEDING && pMWin->eFrmType==TK_RANGE);
+    windowCodeOp(&s, WINDOW_AGGSTEP, regEnd, 0);
+    if( bRPS ) windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+    windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+    if( !bRPS ) windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+  }else{
+    int addr = 0;
+    windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0);
+    if( pMWin->eEnd!=TK_UNBOUNDED ){
+      if( pMWin->eFrmType==TK_RANGE ){
+        int lbl = 0;
+        addr = sqlite3VdbeCurrentAddr(v);
+        if( regEnd ){
+          lbl = sqlite3VdbeMakeLabel(pParse);
+          windowCodeRangeTest(&s, OP_Ge, s.current.csr, regEnd, s.end.csr, lbl);
+        }
+        windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+        windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+        if( regEnd ){
+          sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
+          sqlite3VdbeResolveLabel(v, lbl);
+        }
+      }else{
+        if( regEnd ){
+          addr = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0, 1);
+          VdbeCoverage(v);
+        }
+        windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+        windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+        if( regEnd ) sqlite3VdbeJumpHere(v, addr);
+      }
+    }
+  }
+
+  /* End of the main input loop */
+  sqlite3VdbeResolveLabel(v, lblWhereEnd);
+  sqlite3WhereEnd(pWInfo);
+
+  /* Fall through */
+  if( pMWin->pPartition ){
+    addrInteger = sqlite3VdbeAddOp2(v, OP_Integer, 0, regFlushPart);
+    sqlite3VdbeJumpHere(v, addrGosubFlush);
+  }
+
+  s.regRowid = 0;
+  addrEmpty = sqlite3VdbeAddOp1(v, OP_Rewind, csrWrite);
+  VdbeCoverage(v);
+  if( pMWin->eEnd==TK_PRECEDING ){
+    int bRPS = (pMWin->eStart==TK_PRECEDING && pMWin->eFrmType==TK_RANGE);
+    windowCodeOp(&s, WINDOW_AGGSTEP, regEnd, 0);
+    if( bRPS ) windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+    windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+  }else if( pMWin->eStart==TK_FOLLOWING ){
+    int addrStart;
+    int addrBreak1;
+    int addrBreak2;
+    int addrBreak3;
+    windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0);
+    if( pMWin->eFrmType==TK_RANGE ){
+      addrStart = sqlite3VdbeCurrentAddr(v);
+      addrBreak2 = windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 1);
+      addrBreak1 = windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 1);
+    }else
+    if( pMWin->eEnd==TK_UNBOUNDED ){
+      addrStart = sqlite3VdbeCurrentAddr(v);
+      addrBreak1 = windowCodeOp(&s, WINDOW_RETURN_ROW, regStart, 1);
+      addrBreak2 = windowCodeOp(&s, WINDOW_AGGINVERSE, 0, 1);
+    }else{
+      assert( pMWin->eEnd==TK_FOLLOWING );
+      addrStart = sqlite3VdbeCurrentAddr(v);
+      addrBreak1 = windowCodeOp(&s, WINDOW_RETURN_ROW, regEnd, 1);
+      addrBreak2 = windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 1);
+    }
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart);
+    sqlite3VdbeJumpHere(v, addrBreak2);
+    addrStart = sqlite3VdbeCurrentAddr(v);
+    addrBreak3 = windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 1);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart);
+    sqlite3VdbeJumpHere(v, addrBreak1);
+    sqlite3VdbeJumpHere(v, addrBreak3);
+  }else{
+    int addrBreak;
+    int addrStart;
+    windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0);
+    addrStart = sqlite3VdbeCurrentAddr(v);
+    addrBreak = windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 1);
+    windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart);
+    sqlite3VdbeJumpHere(v, addrBreak);
+  }
+  sqlite3VdbeJumpHere(v, addrEmpty);
+
+  sqlite3VdbeAddOp1(v, OP_ResetSorter, s.current.csr);
+  if( pMWin->pPartition ){
+    if( pMWin->regStartRowid ){
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regStartRowid);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, pMWin->regEndRowid);
+    }
+    sqlite3VdbeChangeP1(v, addrInteger, sqlite3VdbeCurrentAddr(v));
+    sqlite3VdbeAddOp1(v, OP_Return, regFlushPart);
+  }
+}
+
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/************** End of window.c **********************************************/
+/************** Begin file parse.c *******************************************/
+/* This file is automatically generated by Lemon from input grammar
+** source file "parse.y" with these options:
+**
+**   -DSQLITE_ENABLE_UPDATE_DELETE_LIMIT
+*/
+/*
+** 2001-09-15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains SQLite's SQL parser.
+**
+** The canonical source code to this file ("parse.y") is a Lemon grammar
+** file that specifies the input grammar and actions to take while parsing.
+** That input file is processed by Lemon to generate a C-language
+** implementation of a parser for the given grammar.  You might be reading
+** this comment as part of the translated C-code.  Edits should be made
+** to the original parse.y sources.
+*/
+
+/* #include "sqliteInt.h" */
+
+/*
+** Disable all error recovery processing in the parser push-down
+** automaton.
+*/
+#define YYNOERRORRECOVERY 1
+
+/*
+** Make yytestcase() the same as testcase()
+*/
+#define yytestcase(X) testcase(X)
+
+/*
+** Indicate that sqlite3ParserFree() will never be called with a null
+** pointer.
+*/
+#define YYPARSEFREENEVERNULL 1
+
+/*
+** In the amalgamation, the parse.c file generated by lemon and the
+** tokenize.c file are concatenated.  In that case, sqlite3RunParser()
+** has access to the the size of the yyParser object and so the parser
+** engine can be allocated from stack.  In that case, only the
+** sqlite3ParserInit() and sqlite3ParserFinalize() routines are invoked
+** and the sqlite3ParserAlloc() and sqlite3ParserFree() routines can be
+** omitted.
+*/
+#ifdef SQLITE_AMALGAMATION
+# define sqlite3Parser_ENGINEALWAYSONSTACK 1
+#endif
+
+/*
+** Alternative datatype for the argument to the malloc() routine passed
+** into sqlite3ParserAlloc().  The default is size_t.
+*/
+#define YYMALLOCARGTYPE  u64
+
+/*
+** An instance of the following structure describes the event of a
+** TRIGGER.  "a" is the event type, one of TK_UPDATE, TK_INSERT,
+** TK_DELETE, or TK_INSTEAD.  If the event is of the form
+**
+**      UPDATE ON (a,b,c)
+**
+** Then the "b" IdList records the list "a,b,c".
+*/
+struct TrigEvent { int a; IdList * b; };
+
+struct FrameBound     { int eType; Expr *pExpr; };
+
+/*
+** Generate a syntax error
+*/
+static void parserSyntaxError(Parse *pParse, Token *p){
+  sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", p);
+}
+
+/*
+** Disable lookaside memory allocation for objects that might be
+** shared across database connections.
+*/
+static void disableLookaside(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  pParse->disableLookaside++;
+  DisableLookaside;
+}
+
+#if !defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) \
+ && defined(SQLITE_UDL_CAPABLE_PARSER)
+/*
+** Issue an error message if an ORDER BY or LIMIT clause occurs on an
+** UPDATE or DELETE statement.
+*/
+static void updateDeleteLimitError(
+  Parse *pParse,
+  ExprList *pOrderBy,
+  Expr *pLimit
+){
+  if( pOrderBy ){
+    sqlite3ErrorMsg(pParse, "syntax error near \"ORDER BY\"");
+  }else{
+    sqlite3ErrorMsg(pParse, "syntax error near \"LIMIT\"");
+  }
+  sqlite3ExprListDelete(pParse->db, pOrderBy);
+  sqlite3ExprDelete(pParse->db, pLimit);
+}
+#endif /* SQLITE_ENABLE_UPDATE_DELETE_LIMIT */
+
+
+  /*
+  ** For a compound SELECT statement, make sure p->pPrior->pNext==p for
+  ** all elements in the list.  And make sure list length does not exceed
+  ** SQLITE_LIMIT_COMPOUND_SELECT.
+  */
+  static void parserDoubleLinkSelect(Parse *pParse, Select *p){
+    assert( p!=0 );
+    if( p->pPrior ){
+      Select *pNext = 0, *pLoop = p;
+      int mxSelect, cnt = 1;
+      while(1){
+        pLoop->pNext = pNext;
+        pLoop->selFlags |= SF_Compound;
+        pNext = pLoop;
+        pLoop = pLoop->pPrior;
+        if( pLoop==0 ) break;
+        cnt++;
+        if( pLoop->pOrderBy || pLoop->pLimit ){
+          sqlite3ErrorMsg(pParse,"%s clause should come after %s not before",
+             pLoop->pOrderBy!=0 ? "ORDER BY" : "LIMIT",
+             sqlite3SelectOpName(pNext->op));
+          break;
+        }
+      }
+      if( (p->selFlags & (SF_MultiValue|SF_Values))==0
+       && (mxSelect = pParse->db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT])>0
+       && cnt>mxSelect
+      ){
+        sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
+      }
+    }
+  }
+
+  /* Attach a With object describing the WITH clause to a Select
+  ** object describing the query for which the WITH clause is a prefix.
+  */
+  static Select *attachWithToSelect(Parse *pParse, Select *pSelect, With *pWith){
+    if( pSelect ){
+      pSelect->pWith = pWith;
+      parserDoubleLinkSelect(pParse, pSelect);
+    }else{
+      sqlite3WithDelete(pParse->db, pWith);
+    }
+    return pSelect;
+  }
+
+  /* Memory allocator for parser stack resizing.  This is a thin wrapper around
+  ** sqlite3_realloc() that includes a call to sqlite3FaultSim() to facilitate
+  ** testing.
+  */
+  static void *parserStackRealloc(void *pOld, sqlite3_uint64 newSize){
+    return sqlite3FaultSim(700) ? 0 : sqlite3_realloc(pOld, newSize);
+  }
+
+
+  /* Construct a new Expr object from a single token */
+  static Expr *tokenExpr(Parse *pParse, int op, Token t){
+    Expr *p = sqlite3DbMallocRawNN(pParse->db, sizeof(Expr)+t.n+1);
+    if( p ){
+      /* memset(p, 0, sizeof(Expr)); */
+      p->op = (u8)op;
+      p->affExpr = 0;
+      p->flags = EP_Leaf;
+      ExprClearVVAProperties(p);
+      /* p->iAgg = -1; // Not required */
+      p->pLeft = p->pRight = 0;
+      p->pAggInfo = 0;
+      memset(&p->x, 0, sizeof(p->x));
+      memset(&p->y, 0, sizeof(p->y));
+      p->op2 = 0;
+      p->iTable = 0;
+      p->iColumn = 0;
+      p->u.zToken = (char*)&p[1];
+      memcpy(p->u.zToken, t.z, t.n);
+      p->u.zToken[t.n] = 0;
+      p->w.iOfst = (int)(t.z - pParse->zTail);
+      if( sqlite3Isquote(p->u.zToken[0]) ){
+        sqlite3DequoteExpr(p);
+      }
+#if SQLITE_MAX_EXPR_DEPTH>0
+      p->nHeight = 1;
+#endif
+      if( IN_RENAME_OBJECT ){
+        return (Expr*)sqlite3RenameTokenMap(pParse, (void*)p, &t);
+      }
+    }
+    return p;
+  }
+
+
+  /* A routine to convert a binary TK_IS or TK_ISNOT expression into a
+  ** unary TK_ISNULL or TK_NOTNULL expression. */
+  static void binaryToUnaryIfNull(Parse *pParse, Expr *pY, Expr *pA, int op){
+    sqlite3 *db = pParse->db;
+    if( pA && pY && pY->op==TK_NULL && !IN_RENAME_OBJECT ){
+      pA->op = (u8)op;
+      sqlite3ExprDelete(db, pA->pRight);
+      pA->pRight = 0;
+    }
+  }
+
+  /* Add a single new term to an ExprList that is used to store a
+  ** list of identifiers.  Report an error if the ID list contains
+  ** a COLLATE clause or an ASC or DESC keyword, except ignore the
+  ** error while parsing a legacy schema.
+  */
+  static ExprList *parserAddExprIdListTerm(
+    Parse *pParse,
+    ExprList *pPrior,
+    Token *pIdToken,
+    int hasCollate,
+    int sortOrder
+  ){
+    ExprList *p = sqlite3ExprListAppend(pParse, pPrior, 0);
+    if( (hasCollate || sortOrder!=SQLITE_SO_UNDEFINED)
+        && pParse->db->init.busy==0
+    ){
+      sqlite3ErrorMsg(pParse, "syntax error after column name \"%.*s\"",
+                         pIdToken->n, pIdToken->z);
+    }
+    sqlite3ExprListSetName(pParse, p, pIdToken, 1);
+    return p;
+  }
+
+#if TK_SPAN>255
+# error too many tokens in the grammar
+#endif
+/**************** End of %include directives **********************************/
+/* These constants specify the various numeric values for terminal symbols.
+***************** Begin token definitions *************************************/
+#ifndef TK_SEMI
+#define TK_SEMI                            1
+#define TK_EXPLAIN                         2
+#define TK_QUERY                           3
+#define TK_PLAN                            4
+#define TK_BEGIN                           5
+#define TK_TRANSACTION                     6
+#define TK_DEFERRED                        7
+#define TK_IMMEDIATE                       8
+#define TK_EXCLUSIVE                       9
+#define TK_COMMIT                         10
+#define TK_END                            11
+#define TK_ROLLBACK                       12
+#define TK_SAVEPOINT                      13
+#define TK_RELEASE                        14
+#define TK_TO                             15
+#define TK_TABLE                          16
+#define TK_CREATE                         17
+#define TK_IF                             18
+#define TK_NOT                            19
+#define TK_EXISTS                         20
+#define TK_TEMP                           21
+#define TK_LP                             22
+#define TK_RP                             23
+#define TK_AS                             24
+#define TK_COMMA                          25
+#define TK_WITHOUT                        26
+#define TK_ABORT                          27
+#define TK_ACTION                         28
+#define TK_AFTER                          29
+#define TK_ANALYZE                        30
+#define TK_ASC                            31
+#define TK_ATTACH                         32
+#define TK_BEFORE                         33
+#define TK_BY                             34
+#define TK_CASCADE                        35
+#define TK_CAST                           36
+#define TK_CONFLICT                       37
+#define TK_DATABASE                       38
+#define TK_DESC                           39
+#define TK_DETACH                         40
+#define TK_EACH                           41
+#define TK_FAIL                           42
+#define TK_OR                             43
+#define TK_AND                            44
+#define TK_IS                             45
+#define TK_ISNOT                          46
+#define TK_MATCH                          47
+#define TK_LIKE_KW                        48
+#define TK_BETWEEN                        49
+#define TK_IN                             50
+#define TK_ISNULL                         51
+#define TK_NOTNULL                        52
+#define TK_NE                             53
+#define TK_EQ                             54
+#define TK_GT                             55
+#define TK_LE                             56
+#define TK_LT                             57
+#define TK_GE                             58
+#define TK_ESCAPE                         59
+#define TK_ID                             60
+#define TK_COLUMNKW                       61
+#define TK_DO                             62
+#define TK_FOR                            63
+#define TK_IGNORE                         64
+#define TK_INITIALLY                      65
+#define TK_INSTEAD                        66
+#define TK_NO                             67
+#define TK_KEY                            68
+#define TK_OF                             69
+#define TK_OFFSET                         70
+#define TK_PRAGMA                         71
+#define TK_RAISE                          72
+#define TK_RECURSIVE                      73
+#define TK_REPLACE                        74
+#define TK_RESTRICT                       75
+#define TK_ROW                            76
+#define TK_ROWS                           77
+#define TK_TRIGGER                        78
+#define TK_VACUUM                         79
+#define TK_VIEW                           80
+#define TK_VIRTUAL                        81
+#define TK_WITH                           82
+#define TK_NULLS                          83
+#define TK_FIRST                          84
+#define TK_LAST                           85
+#define TK_CURRENT                        86
+#define TK_FOLLOWING                      87
+#define TK_PARTITION                      88
+#define TK_PRECEDING                      89
+#define TK_RANGE                          90
+#define TK_UNBOUNDED                      91
+#define TK_EXCLUDE                        92
+#define TK_GROUPS                         93
+#define TK_OTHERS                         94
+#define TK_TIES                           95
+#define TK_GENERATED                      96
+#define TK_ALWAYS                         97
+#define TK_MATERIALIZED                   98
+#define TK_REINDEX                        99
+#define TK_RENAME                         100
+#define TK_CTIME_KW                       101
+#define TK_ANY                            102
+#define TK_BITAND                         103
+#define TK_BITOR                          104
+#define TK_LSHIFT                         105
+#define TK_RSHIFT                         106
+#define TK_PLUS                           107
+#define TK_MINUS                          108
+#define TK_STAR                           109
+#define TK_SLASH                          110
+#define TK_REM                            111
+#define TK_CONCAT                         112
+#define TK_PTR                            113
+#define TK_COLLATE                        114
+#define TK_BITNOT                         115
+#define TK_ON                             116
+#define TK_INDEXED                        117
+#define TK_STRING                         118
+#define TK_JOIN_KW                        119
+#define TK_CONSTRAINT                     120
+#define TK_DEFAULT                        121
+#define TK_NULL                           122
+#define TK_PRIMARY                        123
+#define TK_UNIQUE                         124
+#define TK_CHECK                          125
+#define TK_REFERENCES                     126
+#define TK_AUTOINCR                       127
+#define TK_INSERT                         128
+#define TK_DELETE                         129
+#define TK_UPDATE                         130
+#define TK_SET                            131
+#define TK_DEFERRABLE                     132
+#define TK_FOREIGN                        133
+#define TK_DROP                           134
+#define TK_UNION                          135
+#define TK_ALL                            136
+#define TK_EXCEPT                         137
+#define TK_INTERSECT                      138
+#define TK_SELECT                         139
+#define TK_VALUES                         140
+#define TK_DISTINCT                       141
+#define TK_DOT                            142
+#define TK_FROM                           143
+#define TK_JOIN                           144
+#define TK_USING                          145
+#define TK_ORDER                          146
+#define TK_GROUP                          147
+#define TK_HAVING                         148
+#define TK_LIMIT                          149
+#define TK_WHERE                          150
+#define TK_RETURNING                      151
+#define TK_INTO                           152
+#define TK_NOTHING                        153
+#define TK_FLOAT                          154
+#define TK_BLOB                           155
+#define TK_INTEGER                        156
+#define TK_VARIABLE                       157
+#define TK_CASE                           158
+#define TK_WHEN                           159
+#define TK_THEN                           160
+#define TK_ELSE                           161
+#define TK_INDEX                          162
+#define TK_ALTER                          163
+#define TK_ADD                            164
+#define TK_WINDOW                         165
+#define TK_OVER                           166
+#define TK_FILTER                         167
+#define TK_COLUMN                         168
+#define TK_AGG_FUNCTION                   169
+#define TK_AGG_COLUMN                     170
+#define TK_TRUEFALSE                      171
+#define TK_FUNCTION                       172
+#define TK_UPLUS                          173
+#define TK_UMINUS                         174
+#define TK_TRUTH                          175
+#define TK_REGISTER                       176
+#define TK_VECTOR                         177
+#define TK_SELECT_COLUMN                  178
+#define TK_IF_NULL_ROW                    179
+#define TK_ASTERISK                       180
+#define TK_SPAN                           181
+#define TK_ERROR                          182
+#define TK_QNUMBER                        183
+#define TK_SPACE                          184
+#define TK_COMMENT                        185
+#define TK_ILLEGAL                        186
+#endif
+/**************** End token definitions ***************************************/
+
+/* The next sections is a series of control #defines.
+** various aspects of the generated parser.
+**    YYCODETYPE         is the data type used to store the integer codes
+**                       that represent terminal and non-terminal symbols.
+**                       "unsigned char" is used if there are fewer than
+**                       256 symbols.  Larger types otherwise.
+**    YYNOCODE           is a number of type YYCODETYPE that is not used for
+**                       any terminal or nonterminal symbol.
+**    YYFALLBACK         If defined, this indicates that one or more tokens
+**                       (also known as: "terminal symbols") have fall-back
+**                       values which should be used if the original symbol
+**                       would not parse.  This permits keywords to sometimes
+**                       be used as identifiers, for example.
+**    YYACTIONTYPE       is the data type used for "action codes" - numbers
+**                       that indicate what to do in response to the next
+**                       token.
+**    sqlite3ParserTOKENTYPE     is the data type used for minor type for terminal
+**                       symbols.  Background: A "minor type" is a semantic
+**                       value associated with a terminal or non-terminal
+**                       symbols.  For example, for an "ID" terminal symbol,
+**                       the minor type might be the name of the identifier.
+**                       Each non-terminal can have a different minor type.
+**                       Terminal symbols all have the same minor type, though.
+**                       This macros defines the minor type for terminal
+**                       symbols.
+**    YYMINORTYPE        is the data type used for all minor types.
+**                       This is typically a union of many types, one of
+**                       which is sqlite3ParserTOKENTYPE.  The entry in the union
+**                       for terminal symbols is called "yy0".
+**    YYSTACKDEPTH       is the maximum depth of the parser's stack.  If
+**                       zero the stack is dynamically sized using realloc()
+**    sqlite3ParserARG_SDECL     A static variable declaration for the %extra_argument
+**    sqlite3ParserARG_PDECL     A parameter declaration for the %extra_argument
+**    sqlite3ParserARG_PARAM     Code to pass %extra_argument as a subroutine parameter
+**    sqlite3ParserARG_STORE     Code to store %extra_argument into yypParser
+**    sqlite3ParserARG_FETCH     Code to extract %extra_argument from yypParser
+**    sqlite3ParserCTX_*         As sqlite3ParserARG_ except for %extra_context
+**    YYREALLOC          Name of the realloc() function to use
+**    YYFREE             Name of the free() function to use
+**    YYDYNSTACK         True if stack space should be extended on heap
+**    YYERRORSYMBOL      is the code number of the error symbol.  If not
+**                       defined, then do no error processing.
+**    YYNSTATE           the combined number of states.
+**    YYNRULE            the number of rules in the grammar
+**    YYNTOKEN           Number of terminal symbols
+**    YY_MAX_SHIFT       Maximum value for shift actions
+**    YY_MIN_SHIFTREDUCE Minimum value for shift-reduce actions
+**    YY_MAX_SHIFTREDUCE Maximum value for shift-reduce actions
+**    YY_ERROR_ACTION    The yy_action[] code for syntax error
+**    YY_ACCEPT_ACTION   The yy_action[] code for accept
+**    YY_NO_ACTION       The yy_action[] code for no-op
+**    YY_MIN_REDUCE      Minimum value for reduce actions
+**    YY_MAX_REDUCE      Maximum value for reduce actions
+**    YY_MIN_DSTRCTR     Minimum symbol value that has a destructor
+**    YY_MAX_DSTRCTR     Maximum symbol value that has a destructor
+*/
+#ifndef INTERFACE
+# define INTERFACE 1
+#endif
+/************* Begin control #defines *****************************************/
+#define YYCODETYPE unsigned short int
+#define YYNOCODE 323
+#define YYACTIONTYPE unsigned short int
+#define YYWILDCARD 102
+#define sqlite3ParserTOKENTYPE Token
+typedef union {
+  int yyinit;
+  sqlite3ParserTOKENTYPE yy0;
+  u32 yy9;
+  struct TrigEvent yy28;
+  With* yy125;
+  IdList* yy204;
+  struct FrameBound yy205;
+  TriggerStep* yy319;
+  const char* yy342;
+  Cte* yy361;
+  ExprList* yy402;
+  Upsert* yy403;
+  OnOrUsing yy421;
+  u8 yy444;
+  struct {int value; int mask;} yy481;
+  Window* yy483;
+  int yy502;
+  SrcList* yy563;
+  Expr* yy590;
+  Select* yy637;
+} YYMINORTYPE;
+#ifndef YYSTACKDEPTH
+#define YYSTACKDEPTH 100
+#endif
+#define sqlite3ParserARG_SDECL
+#define sqlite3ParserARG_PDECL
+#define sqlite3ParserARG_PARAM
+#define sqlite3ParserARG_FETCH
+#define sqlite3ParserARG_STORE
+#define YYREALLOC parserStackRealloc
+#define YYFREE sqlite3_free
+#define YYDYNSTACK 1
+#define sqlite3ParserCTX_SDECL Parse *pParse;
+#define sqlite3ParserCTX_PDECL ,Parse *pParse
+#define sqlite3ParserCTX_PARAM ,pParse
+#define sqlite3ParserCTX_FETCH Parse *pParse=yypParser->pParse;
+#define sqlite3ParserCTX_STORE yypParser->pParse=pParse;
+#define YYFALLBACK 1
+#define YYNSTATE             587
+#define YYNRULE              409
+#define YYNRULE_WITH_ACTION  344
+#define YYNTOKEN             187
+#define YY_MAX_SHIFT         586
+#define YY_MIN_SHIFTREDUCE   849
+#define YY_MAX_SHIFTREDUCE   1257
+#define YY_ERROR_ACTION      1258
+#define YY_ACCEPT_ACTION     1259
+#define YY_NO_ACTION         1260
+#define YY_MIN_REDUCE        1261
+#define YY_MAX_REDUCE        1669
+#define YY_MIN_DSTRCTR       206
+#define YY_MAX_DSTRCTR       320
+/************* End control #defines *******************************************/
+#define YY_NLOOKAHEAD ((int)(sizeof(yy_lookahead)/sizeof(yy_lookahead[0])))
+
+/* Define the yytestcase() macro to be a no-op if is not already defined
+** otherwise.
+**
+** Applications can choose to define yytestcase() in the %include section
+** to a macro that can assist in verifying code coverage.  For production
+** code the yytestcase() macro should be turned off.  But it is useful
+** for testing.
+*/
+#ifndef yytestcase
+# define yytestcase(X)
+#endif
+
+/* Macro to determine if stack space has the ability to grow using
+** heap memory.
+*/
+#if YYSTACKDEPTH<=0 || YYDYNSTACK
+# define YYGROWABLESTACK 1
+#else
+# define YYGROWABLESTACK 0
+#endif
+
+/* Guarantee a minimum number of initial stack slots.
+*/
+#if YYSTACKDEPTH<=0
+# undef YYSTACKDEPTH
+# define YYSTACKDEPTH 2  /* Need a minimum stack size */
+#endif
+
+
+/* Next are the tables used to determine what action to take based on the
+** current state and lookahead token.  These tables are used to implement
+** functions that take a state number and lookahead value and return an
+** action integer.
+**
+** Suppose the action integer is N.  Then the action is determined as
+** follows
+**
+**   0 <= N <= YY_MAX_SHIFT             Shift N.  That is, push the lookahead
+**                                      token onto the stack and goto state N.
+**
+**   N between YY_MIN_SHIFTREDUCE       Shift to an arbitrary state then
+**     and YY_MAX_SHIFTREDUCE           reduce by rule N-YY_MIN_SHIFTREDUCE.
+**
+**   N == YY_ERROR_ACTION               A syntax error has occurred.
+**
+**   N == YY_ACCEPT_ACTION              The parser accepts its input.
+**
+**   N == YY_NO_ACTION                  No such action.  Denotes unused
+**                                      slots in the yy_action[] table.
+**
+**   N between YY_MIN_REDUCE            Reduce by rule N-YY_MIN_REDUCE
+**     and YY_MAX_REDUCE
+**
+** The action table is constructed as a single large table named yy_action[].
+** Given state S and lookahead X, the action is computed as either:
+**
+**    (A)   N = yy_action[ yy_shift_ofst[S] + X ]
+**    (B)   N = yy_default[S]
+**
+** The (A) formula is preferred.  The B formula is used instead if
+** yy_lookahead[yy_shift_ofst[S]+X] is not equal to X.
+**
+** The formulas above are for computing the action when the lookahead is
+** a terminal symbol.  If the lookahead is a non-terminal (as occurs after
+** a reduce action) then the yy_reduce_ofst[] array is used in place of
+** the yy_shift_ofst[] array.
+**
+** The following are the tables generated in this section:
+**
+**  yy_action[]        A single table containing all actions.
+**  yy_lookahead[]     A table containing the lookahead for each entry in
+**                     yy_action.  Used to detect hash collisions.
+**  yy_shift_ofst[]    For each state, the offset into yy_action for
+**                     shifting terminals.
+**  yy_reduce_ofst[]   For each state, the offset into yy_action for
+**                     shifting non-terminals after a reduce.
+**  yy_default[]       Default action for each state.
+**
+*********** Begin parsing tables **********************************************/
+#define YY_ACTTAB_COUNT (2207)
+static const YYACTIONTYPE yy_action[] = {
+ /*     0 */   130,  127,  234,  282,  282, 1332,  580, 1311,  464,  289,
+ /*    10 */   289,  580, 1626,  385,  580, 1332,  577,  580,  566,  417,
+ /*    20 */  1304, 1546,  577,  485,  566,  528,  464,  463,  562,   82,
+ /*    30 */    82,  987,  294,  379,   51,   51,  502,   61,   61,  988,
+ /*    40 */    82,   82, 1581,  137,  138,   91,    7, 1232, 1232, 1067,
+ /*    50 */  1070, 1057, 1057,  135,  135,  136,  136,  136,  136,  417,
+ /*    60 */   288,  288,  182,  288,  288,  485,  540,  288,  288,  130,
+ /*    70 */   127,  234,  436,  577,  529,  566,  577,  561,  566, 1294,
+ /*    80 */   577,  425,  566,  137,  138,   91,  563, 1232, 1232, 1067,
+ /*    90 */  1070, 1057, 1057,  135,  135,  136,  136,  136,  136,  296,
+ /*   100 */   464,  402, 1253,  134,  134,  134,  134,  133,  133,  132,
+ /*   110 */   132,  132,  131,  128,  455,  455, 1054, 1054, 1068, 1071,
+ /*   120 */  1259,    1,    1,  586,    2, 1263,  585, 1178, 1263, 1178,
+ /*   130 */   321,  417,  155,  321, 1588,  155,  383,  112,  485, 1345,
+ /*   140 */   460,  299, 1345,  134,  134,  134,  134,  133,  133,  132,
+ /*   150 */   132,  132,  131,  128,  455,  137,  138,   91,  502, 1232,
+ /*   160 */  1232, 1067, 1070, 1057, 1057,  135,  135,  136,  136,  136,
+ /*   170 */   136, 1208,  866, 1285,  288,  288,  283,  288,  288,  527,
+ /*   180 */   527, 1254,  139,  582,    7,  582, 1349,  577, 1173,  566,
+ /*   190 */   577, 1058,  566,  136,  136,  136,  136,  129,  577,  551,
+ /*   200 */   566, 1173,  245, 1545, 1173,  245,  133,  133,  132,  132,
+ /*   210 */   132,  131,  128,  455,  302,  134,  134,  134,  134,  133,
+ /*   220 */   133,  132,  132,  132,  131,  128,  455, 1579, 1208, 1209,
+ /*   230 */  1208,    7,  474,  554,  459,  417,  554,  459,  130,  127,
+ /*   240 */   234,  134,  134,  134,  134,  133,  133,  132,  132,  132,
+ /*   250 */   131,  128,  455,  136,  136,  136,  136,  542,  487,  137,
+ /*   260 */   138,   91, 1023, 1232, 1232, 1067, 1070, 1057, 1057,  135,
+ /*   270 */   135,  136,  136,  136,  136, 1089,  580, 1208,  132,  132,
+ /*   280 */   132,  131,  128,  455,   93,  214,  134,  134,  134,  134,
+ /*   290 */   133,  133,  132,  132,  132,  131,  128,  455,  405,   19,
+ /*   300 */    19,  134,  134,  134,  134,  133,  133,  132,  132,  132,
+ /*   310 */   131,  128,  455, 1502,  430,  267,  348,  471,  334,  134,
+ /*   320 */   134,  134,  134,  133,  133,  132,  132,  132,  131,  128,
+ /*   330 */   455, 1285,  580,    6, 1208, 1209, 1208,  257,  580,  417,
+ /*   340 */   515,  512,  511, 1283,   94, 1023,  468, 1208,  555,  555,
+ /*   350 */   510, 1228, 1575,   44,   38,   51,   51,  415,  580,  417,
+ /*   360 */    45,   51,   51,  137,  138,   91,  534, 1232, 1232, 1067,
+ /*   370 */  1070, 1057, 1057,  135,  135,  136,  136,  136,  136,  402,
+ /*   380 */  1152,   82,   82,  137,  138,   91,   39, 1232, 1232, 1067,
+ /*   390 */  1070, 1057, 1057,  135,  135,  136,  136,  136,  136,  348,
+ /*   400 */    44,  288,  288,  379, 1208, 1209, 1208,  209, 1208, 1228,
+ /*   410 */   320,  571,  475,  580,  577,  580,  566,  580,  316,  264,
+ /*   420 */   231,   46,  160,  134,  134,  134,  134,  133,  133,  132,
+ /*   430 */   132,  132,  131,  128,  455,  303,   82,   82,   82,   82,
+ /*   440 */    82,   82,  446,  134,  134,  134,  134,  133,  133,  132,
+ /*   450 */   132,  132,  131,  128,  455, 1586,  548,  320,  571, 1254,
+ /*   460 */   878, 1586,  384,  386,  417, 1208, 1209, 1208,  364,  182,
+ /*   470 */   288,  288, 1580,  561, 1343,  561,    7,  561, 1281,  476,
+ /*   480 */   350,  530,  535,  577,  560,  566,  443, 1515,  137,  138,
+ /*   490 */    91,  219, 1232, 1232, 1067, 1070, 1057, 1057,  135,  135,
+ /*   500 */   136,  136,  136,  136,  469, 1515, 1517,  536,  417,  288,
+ /*   510 */   288,  427,  516,  288,  288,  415,  288,  288,  878,  130,
+ /*   520 */   127,  234,  577, 1111,  566, 1208,  577, 1111,  566,  577,
+ /*   530 */   564,  566,  137,  138,   91, 1297, 1232, 1232, 1067, 1070,
+ /*   540 */  1057, 1057,  135,  135,  136,  136,  136,  136,  134,  134,
+ /*   550 */   134,  134,  133,  133,  132,  132,  132,  131,  128,  455,
+ /*   560 */   497,  507, 1296, 1208,  257,  288,  288,  515,  512,  511,
+ /*   570 */  1208, 1632, 1173,  123,  572,  275,    4,  510,  577, 1515,
+ /*   580 */   566,  331, 1208, 1209, 1208, 1173,  552,  552, 1173,  261,
+ /*   590 */   575,    7,  134,  134,  134,  134,  133,  133,  132,  132,
+ /*   600 */   132,  131,  128,  455,  108,  537,  130,  127,  234, 1208,
+ /*   610 */   452,  451,  417, 1455,  456,  987,  890,   96, 1602, 1237,
+ /*   620 */  1208, 1209, 1208,  988, 1239, 1454,  569, 1208, 1209, 1208,
+ /*   630 */   229,  526, 1238,  538, 1337, 1337,  137,  138,   91, 1453,
+ /*   640 */  1232, 1232, 1067, 1070, 1057, 1057,  135,  135,  136,  136,
+ /*   650 */   136,  136,  377, 1599,  975, 1044,  417, 1240,  422, 1240,
+ /*   660 */   883,  121,  121,  952,  377, 1599, 1208, 1209, 1208,  122,
+ /*   670 */  1208,  456,  581,  456,  367,  421, 1032,  886,  377, 1599,
+ /*   680 */   137,  138,   91,  466, 1232, 1232, 1067, 1070, 1057, 1057,
+ /*   690 */   135,  135,  136,  136,  136,  136,  134,  134,  134,  134,
+ /*   700 */   133,  133,  132,  132,  132,  131,  128,  455, 1032, 1032,
+ /*   710 */  1034, 1035,   35,  574,  574,  574,  197,  427, 1044,  198,
+ /*   720 */  1208,  123,  572, 1208,    4,  320,  571, 1208, 1209, 1208,
+ /*   730 */    40,  392,  580,  388,  886, 1033,  427, 1192,  575, 1032,
+ /*   740 */   134,  134,  134,  134,  133,  133,  132,  132,  132,  131,
+ /*   750 */   128,  455,  533, 1572, 1208,   19,   19, 1208,  579,  496,
+ /*   760 */   417,  157,  456,  493, 1191, 1335, 1335,    5, 1208,  953,
+ /*   770 */   435, 1032, 1032, 1034,  569,   22,   22, 1208, 1209, 1208,
+ /*   780 */  1208, 1209, 1208,  481,  137,  138,   91,  212, 1232, 1232,
+ /*   790 */  1067, 1070, 1057, 1057,  135,  135,  136,  136,  136,  136,
+ /*   800 */  1192,   48,  111, 1044,  417, 1208,  213,  974, 1045,  121,
+ /*   810 */   121, 1208, 1209, 1208, 1208, 1209, 1208,  122,  221,  456,
+ /*   820 */   581,  456,   44,  491, 1032, 1208, 1209, 1208,  137,  138,
+ /*   830 */    91,  382, 1232, 1232, 1067, 1070, 1057, 1057,  135,  135,
+ /*   840 */   136,  136,  136,  136,  134,  134,  134,  134,  133,  133,
+ /*   850 */   132,  132,  132,  131,  128,  455, 1032, 1032, 1034, 1035,
+ /*   860 */    35,  465, 1208, 1209, 1208, 1573, 1044,  381,  214, 1153,
+ /*   870 */  1661,  539, 1661,  441,  906,  320,  571, 1572,  368,  320,
+ /*   880 */   571,  416,  329, 1033,  523, 1192,    3, 1032,  134,  134,
+ /*   890 */   134,  134,  133,  133,  132,  132,  132,  131,  128,  455,
+ /*   900 */  1663,  403, 1173,  307,  897,  307,  519,  580,  417,  214,
+ /*   910 */   502,  948, 1028,  544,  907, 1173,  947,  396, 1173, 1032,
+ /*   920 */  1032, 1034,  410,  298, 1208,   50, 1153, 1662,  417, 1662,
+ /*   930 */   145,  145,  137,  138,   91,  293, 1232, 1232, 1067, 1070,
+ /*   940 */  1057, 1057,  135,  135,  136,  136,  136,  136, 1192, 1151,
+ /*   950 */   518, 1572,  137,  138,   91, 1509, 1232, 1232, 1067, 1070,
+ /*   960 */  1057, 1057,  135,  135,  136,  136,  136,  136,  438,  323,
+ /*   970 */   439,  543,  111, 1510,  274,  291,  376,  521,  371,  520,
+ /*   980 */   262, 1208, 1209, 1208, 1578,  485,  367,  580,    7, 1573,
+ /*   990 */  1572,  381,  134,  134,  134,  134,  133,  133,  132,  132,
+ /*  1000 */   132,  131,  128,  455, 1572,  580, 1151,  580,  232,  580,
+ /*  1010 */    19,   19,  134,  134,  134,  134,  133,  133,  132,  132,
+ /*  1020 */   132,  131,  128,  455, 1173,  437,  580, 1211,   19,   19,
+ /*  1030 */    19,   19,   19,   19, 1631,  580,  915, 1173,   47,  120,
+ /*  1040 */  1173,  117,  417,  306,  502,  442, 1129,  206,  340,   19,
+ /*  1050 */    19, 1439,   49,  453,  453,  453, 1372,  315,   81,   81,
+ /*  1060 */   580,  304,  417, 1574,  207,  381,  137,  138,   91,  115,
+ /*  1070 */  1232, 1232, 1067, 1070, 1057, 1057,  135,  135,  136,  136,
+ /*  1080 */   136,  136,  580,   82,   82, 1211,  137,  138,   91, 1344,
+ /*  1090 */  1232, 1232, 1067, 1070, 1057, 1057,  135,  135,  136,  136,
+ /*  1100 */   136,  136, 1573,  390,  381,   82,   82,  467, 1130, 1556,
+ /*  1110 */   337,  467,  339,  131,  128,  455, 1573,  161,  381,   16,
+ /*  1120 */   317,  391,  432, 1131,  452,  451,  134,  134,  134,  134,
+ /*  1130 */   133,  133,  132,  132,  132,  131,  128,  455, 1132,  580,
+ /*  1140 */  1109,   10,  449,  267,  580, 1558,  134,  134,  134,  134,
+ /*  1150 */   133,  133,  132,  132,  132,  131,  128,  455,  536,  580,
+ /*  1160 */   926,  580,   19,   19,  580, 1577,  580,  147,  147,    7,
+ /*  1170 */   927, 1240,  502, 1240,  580,  491,  417,  556,  285, 1228,
+ /*  1180 */   973,  215,   82,   82,   66,   66, 1439,   67,   67,   21,
+ /*  1190 */    21, 1114, 1114,  499,  338,  297,  417,   53,   53,  297,
+ /*  1200 */   137,  138,   91,  119, 1232, 1232, 1067, 1070, 1057, 1057,
+ /*  1210 */   135,  135,  136,  136,  136,  136,  417, 1340, 1315,  450,
+ /*  1220 */   137,  138,   91,  227, 1232, 1232, 1067, 1070, 1057, 1057,
+ /*  1230 */   135,  135,  136,  136,  136,  136,  578, 1228,  940,  940,
+ /*  1240 */   137,  126,   91,  141, 1232, 1232, 1067, 1070, 1057, 1057,
+ /*  1250 */   135,  135,  136,  136,  136,  136,  537,  433,  476,  350,
+ /*  1260 */   134,  134,  134,  134,  133,  133,  132,  132,  132,  131,
+ /*  1270 */   128,  455,  580,  461,  233,  347, 1439,  407,  502, 1554,
+ /*  1280 */   134,  134,  134,  134,  133,  133,  132,  132,  132,  131,
+ /*  1290 */   128,  455,  580,  324,  580,   82,   82,  491,  580,  973,
+ /*  1300 */   134,  134,  134,  134,  133,  133,  132,  132,  132,  131,
+ /*  1310 */   128,  455,  288,  288,  550,   68,   68,   54,   54,  557,
+ /*  1320 */   417,   69,   69,  355,    6,  577,  948,  566,  414,  413,
+ /*  1330 */  1439,  947,  454,  549,  260,  259,  258,  580,  158,  580,
+ /*  1340 */   417,  222, 1184,  483,  973,  138,   91,  434, 1232, 1232,
+ /*  1350 */  1067, 1070, 1057, 1057,  135,  135,  136,  136,  136,  136,
+ /*  1360 */    70,   70,   71,   71,  580, 1130,   91,  580, 1232, 1232,
+ /*  1370 */  1067, 1070, 1057, 1057,  135,  135,  136,  136,  136,  136,
+ /*  1380 */  1131,  166,  854,  855,  856, 1286,  423,   72,   72,  108,
+ /*  1390 */    73,   73, 1314,  362, 1184, 1132,  580,  305,  580,  123,
+ /*  1400 */   572,  498,    4,  492,  134,  134,  134,  134,  133,  133,
+ /*  1410 */   132,  132,  132,  131,  128,  455,  575,  568,  538,   55,
+ /*  1420 */    55,   56,   56,  580,  134,  134,  134,  134,  133,  133,
+ /*  1430 */   132,  132,  132,  131,  128,  455,  580, 1108,  233, 1108,
+ /*  1440 */   456, 1606,  586,    2, 1263,  580,   57,   57,  580,  321,
+ /*  1450 */   580,  155,  569, 1439,  489,  357,  580,  360, 1345,   59,
+ /*  1460 */    59,  580,   44,  973,  573,  423,  580,  238,   60,   60,
+ /*  1470 */   261,   74,   74,   75,   75,  287,  231,  580, 1370,   76,
+ /*  1480 */    76, 1044,  424,  184,   20,   20,  580,  121,  121,   77,
+ /*  1490 */    77,   97,  218,  288,  288,  122,  125,  456,  581,  456,
+ /*  1500 */   143,  143, 1032,  580,  524,  580,  577,  580,  566,  144,
+ /*  1510 */   144,  478,  227, 1248,  482,  123,  572,  580,    4,  320,
+ /*  1520 */   571,  245,  415,  580,  447,  415,   78,   78,   62,   62,
+ /*  1530 */    79,   79,  575,  319, 1032, 1032, 1034, 1035,   35,  422,
+ /*  1540 */    63,   63,  580,  290,  415,    9,   80,   80, 1148,  580,
+ /*  1550 */   404,  580,  490,  459,  580, 1227,  456,  580,  325,  346,
+ /*  1560 */   580,  111,  580, 1192,  242,   64,   64,  477,  569,  580,
+ /*  1570 */    23,  580,  170,  170,  171,  171,  580,   87,   87,  328,
+ /*  1580 */    65,   65,  546,   83,   83,  146,  146,  545,  123,  572,
+ /*  1590 */   345,    4,   84,   84,  168,  168,  580, 1044,  580,  148,
+ /*  1600 */   148,  580, 1384,  121,  121,  575, 1025,  580,  266,  580,
+ /*  1610 */   428,  122,  580,  456,  581,  456,  580,  557, 1032,  142,
+ /*  1620 */   142,  169,  169,  580,  162,  162,  532,  893,  375,  456,
+ /*  1630 */   152,  152,  151,  151, 1383,  149,  149,  109,  374,  150,
+ /*  1640 */   150,  569,  580,  484,  580,  266,   86,   86,  580, 1096,
+ /*  1650 */  1032, 1032, 1034, 1035,   35,  546,  486,  580,  266,  470,
+ /*  1660 */   547,  123,  572, 1620,    4,   88,   88,   85,   85,  479,
+ /*  1670 */  1044,   52,   52,  222,  905,  904,  121,  121,  575, 1192,
+ /*  1680 */    58,   58,  244, 1036,  122,  893,  456,  581,  456,  912,
+ /*  1690 */   913, 1032,  300,  351,  508,  111,  263,  365,  165,  111,
+ /*  1700 */   111, 1092,  456,  263,  978, 1157,  266, 1096,  990,  991,
+ /*  1710 */   946,  943,  125,  125,  569, 1107,  876, 1107,  159,  945,
+ /*  1720 */  1313,  125, 1561, 1032, 1032, 1034, 1035,   35,  546,  341,
+ /*  1730 */  1534,  205, 1533,  545,  503, 1593,  494,  352, 1380,  356,
+ /*  1740 */   359, 1036,  361, 1044,  363, 1328, 1312,  370,  567,  121,
+ /*  1750 */   121,  380, 1192, 1393, 1438, 1366,  280,  122, 1378,  456,
+ /*  1760 */   581,  456,  167, 1443, 1032, 1293, 1284, 1272, 1271, 1273,
+ /*  1770 */  1613, 1363,  312,  313,  314,  401,   12,  237,  224, 1425,
+ /*  1780 */   295,  333,  336, 1430,  343,  488,  344,  513, 1375, 1616,
+ /*  1790 */  1376, 1429, 1248,  408,  301,  228, 1032, 1032, 1034, 1035,
+ /*  1800 */    35, 1605, 1196,  458,  349, 1311,  292,  373, 1506, 1505,
+ /*  1810 */   270,  400,  400,  399,  277,  397, 1374, 1373,  863, 1553,
+ /*  1820 */   186,  123,  572,  235,    4, 1192,  395,  210,  211,  223,
+ /*  1830 */  1551,  239, 1245,  327,  426,   96,  220,  195,  575,  140,
+ /*  1840 */   557,  326,  180,  472, 1420,  332,  188, 1413,  335,  570,
+ /*  1850 */   190,  191,  192,  193,  473,  506,  247,  109, 1434,  495,
+ /*  1860 */   251,  199,  456,  406,  480, 1426,   13,  409,  102,   14,
+ /*  1870 */   501, 1511,  241, 1432,  569, 1431,  203,   92,   95, 1500,
+ /*  1880 */   175,  281,  358,   43,  504,  253,  411,  254,  522, 1331,
+ /*  1890 */   104, 1274, 1522,  354,  440, 1322,  255, 1330, 1630, 1629,
+ /*  1900 */   240,  897,  229, 1044,  444, 1321,  445,  448,  269,  121,
+ /*  1910 */   121, 1329,  531,  268,  310,  412, 1398,  122, 1301,  456,
+ /*  1920 */   581,  456, 1300,  372, 1032, 1299, 1628,  378,  311,   90,
+ /*  1930 */   572,   11,    4, 1397, 1598,  418, 1487,  389,  116,  110,
+ /*  1940 */   320,  571, 1584,  559,  318,  541,  575, 1583,   42, 1354,
+ /*  1950 */   387,  583,  216, 1353, 1202,  276, 1032, 1032, 1034, 1035,
+ /*  1960 */    35,  393,  394,  278,  462,  279,  419,  584, 1538, 1269,
+ /*  1970 */   456, 1264,  172,  420,  173, 1539, 1537, 1536,  156,  308,
+ /*  1980 */   225,   89,  569,  850,  226, 1192,  457,  174,  217,  236,
+ /*  1990 */   322,  154, 1106, 1104,  187,  330,  176, 1227,  929,  189,
+ /*  2000 */   243,  342,  246, 1120,  194,  177,  178,  429,  431,   98,
+ /*  2010 */   196, 1044,   99,  185,  100,  101,  179,  121,  121, 1123,
+ /*  2020 */   248,  249, 1119,  163,  250,  122,   24,  456,  581,  456,
+ /*  2030 */  1196,  458, 1032,  353,  292,  266, 1112,  200, 1242,  400,
+ /*  2040 */   400,  399,  277,  397,  500,  252,  863,  201,  292,   15,
+ /*  2050 */   865,  558,  505,  400,  400,  399,  277,  397,  374,  239,
+ /*  2060 */   863,  327,  256,  202, 1032, 1032, 1034, 1035,   35,  326,
+ /*  2070 */   103,   25,   26,  239,  509,  327,  366,  514,  369,  895,
+ /*  2080 */   908,  517,  105,  326,  309,  164,  525,  106,  181,   27,
+ /*  2090 */  1189, 1073,   17, 1192,  107, 1159, 1158,  284,  230,  286,
+ /*  2100 */   241,  204,  125, 1175,  982,  265, 1182,  976,  175,   28,
+ /*  2110 */  1179,   43,   29, 1177,  241,   30,   31,    8, 1183,   32,
+ /*  2120 */  1164,   41,  175,  208,  553,   43,  111,   33,  240, 1087,
+ /*  2130 */  1074,  113,  114, 1072, 1076,   34, 1077,  565, 1128,  118,
+ /*  2140 */   271,   36,  240,   18,  939, 1037,  877,  272,  124,   37,
+ /*  2150 */   398, 1198, 1197,  576,  183,  273,  153, 1621, 1260, 1260,
+ /*  2160 */  1260, 1260, 1260,  418, 1260, 1260, 1260, 1260,  320,  571,
+ /*  2170 */  1260, 1260, 1260, 1260, 1260, 1260, 1260,  418, 1260, 1260,
+ /*  2180 */  1260, 1260,  320,  571, 1260, 1260, 1260, 1260, 1260, 1260,
+ /*  2190 */  1260, 1260,  462, 1260, 1260, 1260, 1260, 1260, 1260, 1260,
+ /*  2200 */  1260, 1260, 1260, 1260, 1260, 1260,  462,
+};
+static const YYCODETYPE yy_lookahead[] = {
+ /*     0 */   277,  278,  279,  241,  242,  225,  195,  227,  195,  241,
+ /*    10 */   242,  195,  217,  221,  195,  235,  254,  195,  256,   19,
+ /*    20 */   225,  298,  254,  195,  256,  206,  213,  214,  206,  218,
+ /*    30 */   219,   31,  206,  195,  218,  219,  195,  218,  219,   39,
+ /*    40 */   218,  219,  313,   43,   44,   45,  317,   47,   48,   49,
+ /*    50 */    50,   51,   52,   53,   54,   55,   56,   57,   58,   19,
+ /*    60 */   241,  242,  195,  241,  242,  195,  255,  241,  242,  277,
+ /*    70 */   278,  279,  234,  254,  255,  256,  254,  255,  256,  218,
+ /*    80 */   254,  240,  256,   43,   44,   45,  264,   47,   48,   49,
+ /*    90 */    50,   51,   52,   53,   54,   55,   56,   57,   58,  271,
+ /*   100 */   287,   22,   23,  103,  104,  105,  106,  107,  108,  109,
+ /*   110 */   110,  111,  112,  113,  114,  114,   47,   48,   49,   50,
+ /*   120 */   187,  188,  189,  190,  191,  192,  190,   87,  192,   89,
+ /*   130 */   197,   19,  199,  197,  318,  199,  320,   25,  195,  206,
+ /*   140 */   299,  271,  206,  103,  104,  105,  106,  107,  108,  109,
+ /*   150 */   110,  111,  112,  113,  114,   43,   44,   45,  195,   47,
+ /*   160 */    48,   49,   50,   51,   52,   53,   54,   55,   56,   57,
+ /*   170 */    58,   60,   21,  195,  241,  242,  215,  241,  242,  312,
+ /*   180 */   313,  102,   70,  205,  317,  207,  242,  254,   77,  256,
+ /*   190 */   254,  122,  256,   55,   56,   57,   58,   59,  254,   88,
+ /*   200 */   256,   90,  269,  240,   93,  269,  107,  108,  109,  110,
+ /*   210 */   111,  112,  113,  114,  271,  103,  104,  105,  106,  107,
+ /*   220 */   108,  109,  110,  111,  112,  113,  114,  313,  117,  118,
+ /*   230 */   119,  317,   81,  195,  301,   19,  195,  301,  277,  278,
+ /*   240 */   279,  103,  104,  105,  106,  107,  108,  109,  110,  111,
+ /*   250 */   112,  113,  114,   55,   56,   57,   58,  146,  195,   43,
+ /*   260 */    44,   45,   74,   47,   48,   49,   50,   51,   52,   53,
+ /*   270 */    54,   55,   56,   57,   58,  124,  195,   60,  109,  110,
+ /*   280 */   111,  112,  113,  114,   68,  195,  103,  104,  105,  106,
+ /*   290 */   107,  108,  109,  110,  111,  112,  113,  114,  208,  218,
+ /*   300 */   219,  103,  104,  105,  106,  107,  108,  109,  110,  111,
+ /*   310 */   112,  113,  114,  162,  233,   24,  128,  129,  130,  103,
+ /*   320 */   104,  105,  106,  107,  108,  109,  110,  111,  112,  113,
+ /*   330 */   114,  195,  195,  215,  117,  118,  119,  120,  195,   19,
+ /*   340 */   123,  124,  125,  207,   24,   74,  246,   60,  310,  311,
+ /*   350 */   133,   60,  311,   82,   22,  218,  219,  257,  195,   19,
+ /*   360 */    73,  218,  219,   43,   44,   45,  206,   47,   48,   49,
+ /*   370 */    50,   51,   52,   53,   54,   55,   56,   57,   58,   22,
+ /*   380 */    23,  218,  219,   43,   44,   45,   54,   47,   48,   49,
+ /*   390 */    50,   51,   52,   53,   54,   55,   56,   57,   58,  128,
+ /*   400 */    82,  241,  242,  195,  117,  118,  119,  289,   60,  118,
+ /*   410 */   139,  140,  294,  195,  254,  195,  256,  195,  255,  259,
+ /*   420 */   260,   73,   22,  103,  104,  105,  106,  107,  108,  109,
+ /*   430 */   110,  111,  112,  113,  114,  206,  218,  219,  218,  219,
+ /*   440 */   218,  219,  234,  103,  104,  105,  106,  107,  108,  109,
+ /*   450 */   110,  111,  112,  113,  114,  318,  319,  139,  140,  102,
+ /*   460 */    60,  318,  319,  221,   19,  117,  118,  119,   23,  195,
+ /*   470 */   241,  242,  313,  255,  206,  255,  317,  255,  206,  129,
+ /*   480 */   130,  206,  264,  254,  264,  256,  264,  195,   43,   44,
+ /*   490 */    45,  151,   47,   48,   49,   50,   51,   52,   53,   54,
+ /*   500 */    55,   56,   57,   58,  246,  213,  214,   19,   19,  241,
+ /*   510 */   242,  195,   23,  241,  242,  257,  241,  242,  118,  277,
+ /*   520 */   278,  279,  254,   29,  256,   60,  254,   33,  256,  254,
+ /*   530 */   206,  256,   43,   44,   45,  218,   47,   48,   49,   50,
+ /*   540 */    51,   52,   53,   54,   55,   56,   57,   58,  103,  104,
+ /*   550 */   105,  106,  107,  108,  109,  110,  111,  112,  113,  114,
+ /*   560 */    66,   19,  218,   60,  120,  241,  242,  123,  124,  125,
+ /*   570 */    60,  232,   77,   19,   20,   26,   22,  133,  254,  287,
+ /*   580 */   256,  265,  117,  118,  119,   90,  312,  313,   93,   47,
+ /*   590 */    36,  317,  103,  104,  105,  106,  107,  108,  109,  110,
+ /*   600 */   111,  112,  113,  114,  116,  117,  277,  278,  279,   60,
+ /*   610 */   107,  108,   19,  276,   60,   31,   23,  152,  195,  116,
+ /*   620 */   117,  118,  119,   39,  121,  276,   72,  117,  118,  119,
+ /*   630 */   166,  167,  129,  145,  237,  238,   43,   44,   45,  276,
+ /*   640 */    47,   48,   49,   50,   51,   52,   53,   54,   55,   56,
+ /*   650 */    57,   58,  315,  316,  144,  101,   19,  154,  116,  156,
+ /*   660 */    23,  107,  108,  109,  315,  316,  117,  118,  119,  115,
+ /*   670 */    60,  117,  118,  119,  132,  200,  122,   60,  315,  316,
+ /*   680 */    43,   44,   45,  272,   47,   48,   49,   50,   51,   52,
+ /*   690 */    53,   54,   55,   56,   57,   58,  103,  104,  105,  106,
+ /*   700 */   107,  108,  109,  110,  111,  112,  113,  114,  154,  155,
+ /*   710 */   156,  157,  158,  212,  213,  214,   22,  195,  101,   22,
+ /*   720 */    60,   19,   20,   60,   22,  139,  140,  117,  118,  119,
+ /*   730 */    22,  251,  195,  253,  117,  118,  195,  183,   36,  122,
+ /*   740 */   103,  104,  105,  106,  107,  108,  109,  110,  111,  112,
+ /*   750 */   113,  114,  195,  195,   60,  218,  219,   60,  195,  284,
+ /*   760 */    19,   25,   60,  288,   23,  237,  238,   22,   60,  109,
+ /*   770 */   233,  154,  155,  156,   72,  218,  219,  117,  118,  119,
+ /*   780 */   117,  118,  119,  116,   43,   44,   45,  265,   47,   48,
+ /*   790 */    49,   50,   51,   52,   53,   54,   55,   56,   57,   58,
+ /*   800 */   183,  243,   25,  101,   19,   60,  265,  144,   23,  107,
+ /*   810 */   108,  117,  118,  119,  117,  118,  119,  115,  151,  117,
+ /*   820 */   118,  119,   82,  195,  122,  117,  118,  119,   43,   44,
+ /*   830 */    45,  195,   47,   48,   49,   50,   51,   52,   53,   54,
+ /*   840 */    55,   56,   57,   58,  103,  104,  105,  106,  107,  108,
+ /*   850 */   109,  110,  111,  112,  113,  114,  154,  155,  156,  157,
+ /*   860 */   158,  121,  117,  118,  119,  307,  101,  309,  195,   22,
+ /*   870 */    23,  195,   25,   19,   35,  139,  140,  195,   24,  139,
+ /*   880 */   140,  208,  195,  118,  109,  183,   22,  122,  103,  104,
+ /*   890 */   105,  106,  107,  108,  109,  110,  111,  112,  113,  114,
+ /*   900 */   304,  305,   77,  230,  127,  232,   67,  195,   19,  195,
+ /*   910 */   195,  136,   23,   88,   75,   90,  141,  203,   93,  154,
+ /*   920 */   155,  156,  208,  295,   60,  243,   22,   23,   19,   25,
+ /*   930 */   218,  219,   43,   44,   45,  100,   47,   48,   49,   50,
+ /*   940 */    51,   52,   53,   54,   55,   56,   57,   58,  183,  102,
+ /*   950 */    96,  195,   43,   44,   45,  240,   47,   48,   49,   50,
+ /*   960 */    51,   52,   53,   54,   55,   56,   57,   58,  114,  134,
+ /*   970 */   131,  146,   25,  286,  120,  121,  122,  123,  124,  125,
+ /*   980 */   126,  117,  118,  119,  313,  195,  132,  195,  317,  307,
+ /*   990 */   195,  309,  103,  104,  105,  106,  107,  108,  109,  110,
+ /*  1000 */   111,  112,  113,  114,  195,  195,  102,  195,  195,  195,
+ /*  1010 */   218,  219,  103,  104,  105,  106,  107,  108,  109,  110,
+ /*  1020 */   111,  112,  113,  114,   77,  233,  195,   60,  218,  219,
+ /*  1030 */   218,  219,  218,  219,   23,  195,   25,   90,  243,  159,
+ /*  1040 */    93,  161,   19,  233,  195,  233,   23,  233,   16,  218,
+ /*  1050 */   219,  195,  243,  212,  213,  214,  262,  263,  218,  219,
+ /*  1060 */   195,  271,   19,  307,  233,  309,   43,   44,   45,  160,
+ /*  1070 */    47,   48,   49,   50,   51,   52,   53,   54,   55,   56,
+ /*  1080 */    57,   58,  195,  218,  219,  118,   43,   44,   45,  240,
+ /*  1090 */    47,   48,   49,   50,   51,   52,   53,   54,   55,   56,
+ /*  1100 */    57,   58,  307,  195,  309,  218,  219,  263,   12,  195,
+ /*  1110 */    78,  267,   80,  112,  113,  114,  307,   22,  309,   24,
+ /*  1120 */   255,  281,  266,   27,  107,  108,  103,  104,  105,  106,
+ /*  1130 */   107,  108,  109,  110,  111,  112,  113,  114,   42,  195,
+ /*  1140 */    11,   22,  255,   24,  195,  195,  103,  104,  105,  106,
+ /*  1150 */   107,  108,  109,  110,  111,  112,  113,  114,   19,  195,
+ /*  1160 */    64,  195,  218,  219,  195,  313,  195,  218,  219,  317,
+ /*  1170 */    74,  154,  195,  156,  195,  195,   19,  233,   23,   60,
+ /*  1180 */    25,   24,  218,  219,  218,  219,  195,  218,  219,  218,
+ /*  1190 */   219,  128,  129,  130,  162,  263,   19,  218,  219,  267,
+ /*  1200 */    43,   44,   45,  160,   47,   48,   49,   50,   51,   52,
+ /*  1210 */    53,   54,   55,   56,   57,   58,   19,  240,  228,  255,
+ /*  1220 */    43,   44,   45,   25,   47,   48,   49,   50,   51,   52,
+ /*  1230 */    53,   54,   55,   56,   57,   58,  135,  118,  137,  138,
+ /*  1240 */    43,   44,   45,   22,   47,   48,   49,   50,   51,   52,
+ /*  1250 */    53,   54,   55,   56,   57,   58,  117,  266,  129,  130,
+ /*  1260 */   103,  104,  105,  106,  107,  108,  109,  110,  111,  112,
+ /*  1270 */   113,  114,  195,  195,  119,  295,  195,  206,  195,  195,
+ /*  1280 */   103,  104,  105,  106,  107,  108,  109,  110,  111,  112,
+ /*  1290 */   113,  114,  195,  195,  195,  218,  219,  195,  195,  144,
+ /*  1300 */   103,  104,  105,  106,  107,  108,  109,  110,  111,  112,
+ /*  1310 */   113,  114,  241,  242,   67,  218,  219,  218,  219,  146,
+ /*  1320 */    19,  218,  219,  240,  215,  254,  136,  256,  107,  108,
+ /*  1330 */   195,  141,  255,   86,  128,  129,  130,  195,  165,  195,
+ /*  1340 */    19,  143,   95,  272,   25,   44,   45,  266,   47,   48,
+ /*  1350 */    49,   50,   51,   52,   53,   54,   55,   56,   57,   58,
+ /*  1360 */   218,  219,  218,  219,  195,   12,   45,  195,   47,   48,
+ /*  1370 */    49,   50,   51,   52,   53,   54,   55,   56,   57,   58,
+ /*  1380 */    27,   23,    7,    8,    9,  210,  211,  218,  219,  116,
+ /*  1390 */   218,  219,  228,   16,  147,   42,  195,  295,  195,   19,
+ /*  1400 */    20,  266,   22,  294,  103,  104,  105,  106,  107,  108,
+ /*  1410 */   109,  110,  111,  112,  113,  114,   36,   64,  145,  218,
+ /*  1420 */   219,  218,  219,  195,  103,  104,  105,  106,  107,  108,
+ /*  1430 */   109,  110,  111,  112,  113,  114,  195,  154,  119,  156,
+ /*  1440 */    60,  189,  190,  191,  192,  195,  218,  219,  195,  197,
+ /*  1450 */   195,  199,   72,  195,   19,   78,  195,   80,  206,  218,
+ /*  1460 */   219,  195,   82,  144,  210,  211,  195,   15,  218,  219,
+ /*  1470 */    47,  218,  219,  218,  219,  259,  260,  195,  261,  218,
+ /*  1480 */   219,  101,  302,  303,  218,  219,  195,  107,  108,  218,
+ /*  1490 */   219,  150,  151,  241,  242,  115,   25,  117,  118,  119,
+ /*  1500 */   218,  219,  122,  195,  146,  195,  254,  195,  256,  218,
+ /*  1510 */   219,  246,   25,   61,  246,   19,   20,  195,   22,  139,
+ /*  1520 */   140,  269,  257,  195,  266,  257,  218,  219,  218,  219,
+ /*  1530 */   218,  219,   36,  246,  154,  155,  156,  157,  158,  116,
+ /*  1540 */   218,  219,  195,   22,  257,   49,  218,  219,   23,  195,
+ /*  1550 */    25,  195,  117,  301,  195,   25,   60,  195,  195,   23,
+ /*  1560 */   195,   25,  195,  183,   24,  218,  219,  130,   72,  195,
+ /*  1570 */    22,  195,  218,  219,  218,  219,  195,  218,  219,  195,
+ /*  1580 */   218,  219,   86,  218,  219,  218,  219,   91,   19,   20,
+ /*  1590 */   153,   22,  218,  219,  218,  219,  195,  101,  195,  218,
+ /*  1600 */   219,  195,  195,  107,  108,   36,   23,  195,   25,  195,
+ /*  1610 */    62,  115,  195,  117,  118,  119,  195,  146,  122,  218,
+ /*  1620 */   219,  218,  219,  195,  218,  219,   19,   60,  122,   60,
+ /*  1630 */   218,  219,  218,  219,  195,  218,  219,  150,  132,  218,
+ /*  1640 */   219,   72,  195,   23,  195,   25,  218,  219,  195,   60,
+ /*  1650 */   154,  155,  156,  157,  158,   86,   23,  195,   25,  195,
+ /*  1660 */    91,   19,   20,  142,   22,  218,  219,  218,  219,  130,
+ /*  1670 */   101,  218,  219,  143,  121,  122,  107,  108,   36,  183,
+ /*  1680 */   218,  219,  142,   60,  115,  118,  117,  118,  119,    7,
+ /*  1690 */     8,  122,  153,   23,   23,   25,   25,   23,   23,   25,
+ /*  1700 */    25,   23,   60,   25,   23,   98,   25,  118,   84,   85,
+ /*  1710 */    23,   23,   25,   25,   72,  154,   23,  156,   25,   23,
+ /*  1720 */   228,   25,  195,  154,  155,  156,  157,  158,   86,  195,
+ /*  1730 */   195,  258,  195,   91,  291,  322,  195,  195,  195,  195,
+ /*  1740 */   195,  118,  195,  101,  195,  195,  195,  195,  238,  107,
+ /*  1750 */   108,  195,  183,  195,  195,  195,  290,  115,  195,  117,
+ /*  1760 */   118,  119,  244,  195,  122,  195,  195,  195,  195,  195,
+ /*  1770 */   195,  258,  258,  258,  258,  193,  245,  300,  216,  274,
+ /*  1780 */   247,  270,  270,  274,  296,  296,  248,  222,  262,  198,
+ /*  1790 */   262,  274,   61,  274,  248,  231,  154,  155,  156,  157,
+ /*  1800 */   158,    0,    1,    2,  247,  227,    5,  221,  221,  221,
+ /*  1810 */   142,   10,   11,   12,   13,   14,  262,  262,   17,  202,
+ /*  1820 */   300,   19,   20,  300,   22,  183,  247,  251,  251,  245,
+ /*  1830 */   202,   30,   38,   32,  202,  152,  151,   22,   36,  149,
+ /*  1840 */   146,   40,   43,   18,  252,  251,  236,  252,  251,  283,
+ /*  1850 */   239,  239,  239,  239,  202,   18,  201,  150,  236,  202,
+ /*  1860 */   201,  236,   60,  248,  248,  275,  273,  248,  159,  273,
+ /*  1870 */    63,  286,   71,  275,   72,  275,   22,  297,  297,  248,
+ /*  1880 */    79,  202,  202,   82,  223,  201,  223,  201,  116,  220,
+ /*  1890 */    22,  202,  293,  292,   65,  229,  201,  220,  226,  226,
+ /*  1900 */    99,  127,  166,  101,   24,  229,  114,   83,   92,  107,
+ /*  1910 */   108,  220,  308,  202,  285,  223,  268,  115,  220,  117,
+ /*  1920 */   118,  119,  222,  220,  122,  220,  220,  223,  285,   19,
+ /*  1930 */    20,   22,   22,  268,  316,  134,  280,  202,  159,  148,
+ /*  1940 */   139,  140,  321,  141,  282,  147,   36,  321,   25,  252,
+ /*  1950 */   251,  204,  250,  252,   13,  196,  154,  155,  156,  157,
+ /*  1960 */   158,  249,  248,  196,  163,    6,  306,  194,  215,  194,
+ /*  1970 */    60,  194,  209,  306,  209,  215,  215,  215,  224,  224,
+ /*  1980 */   216,  215,   72,    4,  216,  183,    3,  209,   22,   15,
+ /*  1990 */   164,   16,   23,   23,  152,  140,  131,   25,   20,  143,
+ /*  2000 */    24,   16,  145,    1,  143,  131,  131,   62,   37,   54,
+ /*  2010 */   152,  101,   54,  303,   54,   54,  131,  107,  108,  117,
+ /*  2020 */    34,  142,    1,    5,  116,  115,   22,  117,  118,  119,
+ /*  2030 */     1,    2,  122,  162,    5,   25,   69,   69,   76,   10,
+ /*  2040 */    11,   12,   13,   14,   41,  142,   17,  116,    5,   24,
+ /*  2050 */    20,  141,   19,   10,   11,   12,   13,   14,  132,   30,
+ /*  2060 */    17,   32,  126,   22,  154,  155,  156,  157,  158,   40,
+ /*  2070 */    22,   22,   22,   30,   68,   32,   23,   68,   24,   60,
+ /*  2080 */    28,   97,   22,   40,   68,   23,   22,  150,   37,   34,
+ /*  2090 */    23,   23,   22,  183,   25,   23,   98,   23,  142,   23,
+ /*  2100 */    71,   22,   25,   89,  117,   34,   94,  144,   79,   34,
+ /*  2110 */    76,   82,   34,   87,   71,   34,   34,   44,   76,   34,
+ /*  2120 */    23,   22,   79,   25,   24,   82,   25,   34,   99,   23,
+ /*  2130 */    23,  143,  143,   23,   23,   22,   11,   25,   23,   25,
+ /*  2140 */    22,   22,   99,   22,  136,   23,   23,  142,   22,   22,
+ /*  2150 */    15,    1,    1,   25,   25,  142,   23,  142,  323,  323,
+ /*  2160 */   323,  323,  323,  134,  323,  323,  323,  323,  139,  140,
+ /*  2170 */   323,  323,  323,  323,  323,  323,  323,  134,  323,  323,
+ /*  2180 */   323,  323,  139,  140,  323,  323,  323,  323,  323,  323,
+ /*  2190 */   323,  323,  163,  323,  323,  323,  323,  323,  323,  323,
+ /*  2200 */   323,  323,  323,  323,  323,  323,  163,  323,  323,  323,
+ /*  2210 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2220 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2230 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2240 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2250 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2260 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2270 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2280 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2290 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2300 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2310 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2320 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2330 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2340 */   323,  323,  323,  323,  323,  187,  187,  187,  187,  187,
+ /*  2350 */   187,  187,  187,  187,  187,  187,  187,  187,  187,  187,
+ /*  2360 */   187,  187,  187,  187,  187,  187,  187,  187,  187,  187,
+ /*  2370 */   187,  187,  187,  187,  187,  187,  187,  187,  187,  187,
+ /*  2380 */   187,  187,  187,  187,  187,  187,  187,  187,  187,  187,
+ /*  2390 */   187,  187,  187,  187,
+};
+#define YY_SHIFT_COUNT    (586)
+#define YY_SHIFT_MIN      (0)
+#define YY_SHIFT_MAX      (2151)
+static const unsigned short int yy_shift_ofst[] = {
+ /*     0 */  2029, 1801, 2043, 1380, 1380,  318,  271, 1496, 1569, 1642,
+ /*    10 */   702,  702,  702,  740,  318,  318,  318,  318,  318,    0,
+ /*    20 */     0,  216, 1177,  702,  702,  702,  702,  702,  702,  702,
+ /*    30 */   702,  702,  702,  702,  702,  702,  702,  702,  503,  503,
+ /*    40 */   111,  111,  217,  287,  348,  610,  610,  736,  736,  736,
+ /*    50 */   736,   40,  112,  320,  340,  445,  489,  593,  637,  741,
+ /*    60 */   785,  889,  909, 1023, 1043, 1157, 1177, 1177, 1177, 1177,
+ /*    70 */  1177, 1177, 1177, 1177, 1177, 1177, 1177, 1177, 1177, 1177,
+ /*    80 */  1177, 1177, 1177, 1177, 1197, 1177, 1301, 1321, 1321,  554,
+ /*    90 */  1802, 1910,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   100 */   702,  702,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   110 */   702,  702,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   120 */   702,  702,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   130 */   702,  702,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   140 */   702,  702,  138,  198,  198,  198,  198,  198,  198,  198,
+ /*   150 */   183,   99,  169,  549,  610,  151,  542,  610,  610, 1017,
+ /*   160 */  1017,  610, 1001,  350,  464,  464,  464,  586,    1,    1,
+ /*   170 */  2207, 2207,  854,  854,  854,  465,  694,  694,  694,  694,
+ /*   180 */  1096, 1096,  825,  549,  847,  904,  610,  610,  610,  610,
+ /*   190 */   610,  610,  610,  610,  610,  610,  610,  610,  610,  610,
+ /*   200 */   610,  610,  610,  610,  610,  488,  947,  947,  610, 1129,
+ /*   210 */   495,  495, 1139, 1139,  967,  967, 1173, 2207, 2207, 2207,
+ /*   220 */  2207, 2207, 2207, 2207,  617,  765,  765,  697,  444,  708,
+ /*   230 */   660,  745,  510,  663,  864,  610,  610,  610,  610,  610,
+ /*   240 */   610,  610,  610,  610,  610,  188,  610,  610,  610,  610,
+ /*   250 */   610,  610,  610,  610,  610,  610,  610,  610,  839,  839,
+ /*   260 */   839,  610,  610,  610, 1155,  610,  610,  610, 1119, 1247,
+ /*   270 */   610, 1353,  610,  610,  610,  610,  610,  610,  610,  610,
+ /*   280 */  1063,  494, 1101,  291,  291,  291,  291, 1319, 1101, 1101,
+ /*   290 */   775, 1221, 1375, 1452,  667, 1341, 1198, 1341, 1435, 1487,
+ /*   300 */   667,  667, 1487,  667, 1198, 1435,  777, 1011, 1423,  584,
+ /*   310 */   584,  584, 1273, 1273, 1273, 1273, 1471, 1471,  880, 1530,
+ /*   320 */  1190, 1095, 1731, 1731, 1668, 1668, 1794, 1794, 1668, 1683,
+ /*   330 */  1685, 1815, 1690, 1694, 1799, 1690, 1694, 1825, 1825, 1825,
+ /*   340 */  1825, 1668, 1837, 1707, 1685, 1685, 1707, 1815, 1799, 1707,
+ /*   350 */  1799, 1707, 1668, 1837, 1709, 1807, 1668, 1837, 1854, 1668,
+ /*   360 */  1837, 1668, 1837, 1854, 1772, 1772, 1772, 1829, 1868, 1868,
+ /*   370 */  1854, 1772, 1774, 1772, 1829, 1772, 1772, 1736, 1880, 1792,
+ /*   380 */  1792, 1854, 1668, 1816, 1816, 1824, 1824, 1690, 1694, 1909,
+ /*   390 */  1668, 1779, 1690, 1791, 1798, 1707, 1923, 1941, 1941, 1959,
+ /*   400 */  1959, 1959, 2207, 2207, 2207, 2207, 2207, 2207, 2207, 2207,
+ /*   410 */  2207, 2207, 2207, 2207, 2207, 2207, 2207,   69, 1032,   79,
+ /*   420 */   357, 1377, 1206,  400, 1525,  835,  332, 1540, 1437, 1539,
+ /*   430 */  1536, 1548, 1583, 1620, 1633, 1670, 1671, 1674, 1567, 1553,
+ /*   440 */  1682, 1506, 1675, 1358, 1607, 1589, 1678, 1681, 1624, 1687,
+ /*   450 */  1688, 1283, 1561, 1693, 1696, 1623, 1521, 1979, 1983, 1966,
+ /*   460 */  1826, 1974, 1975, 1969, 1970, 1855, 1842, 1865, 1972, 1972,
+ /*   470 */  1976, 1856, 1978, 1857, 1985, 2002, 1861, 1874, 1972, 1875,
+ /*   480 */  1945, 1971, 1972, 1858, 1955, 1958, 1960, 1961, 1885, 1902,
+ /*   490 */  1986, 1879, 2021, 2018, 2004, 1908, 1871, 1967, 2010, 1968,
+ /*   500 */  1962, 2003, 1903, 1931, 2025, 2030, 2033, 1926, 1936, 2041,
+ /*   510 */  2006, 2048, 2049, 2053, 2050, 2009, 2019, 2054, 1984, 2052,
+ /*   520 */  2060, 2016, 2051, 2062, 2055, 1937, 2064, 2067, 2068, 2069,
+ /*   530 */  2072, 2070, 1998, 1956, 2074, 2076, 1987, 2071, 2079, 1963,
+ /*   540 */  2077, 2075, 2078, 2081, 2082, 2014, 2034, 2026, 2073, 2042,
+ /*   550 */  2012, 2085, 2097, 2099, 2100, 2098, 2101, 2093, 1988, 1989,
+ /*   560 */  2106, 2077, 2107, 2110, 2111, 2113, 2112, 2114, 2115, 2118,
+ /*   570 */  2125, 2119, 2121, 2122, 2123, 2126, 2127, 2128, 2008, 2005,
+ /*   580 */  2013, 2015, 2129, 2133, 2135, 2150, 2151,
+};
+#define YY_REDUCE_COUNT (416)
+#define YY_REDUCE_MIN   (-277)
+#define YY_REDUCE_MAX   (1778)
+static const short yy_reduce_ofst[] = {
+ /*     0 */   -67, 1252,  -64, -178, -181,  160, 1071,  143, -184,  137,
+ /*    10 */   218,  220,  222, -174,  229,  268,  272,  275,  324, -208,
+ /*    20 */   242, -277,  -39,   81,  537,  792,  810,  812, -189,  814,
+ /*    30 */   831,  163,  865,  944,  887,  840,  964, 1077, -187,  292,
+ /*    40 */  -133,  274,  673,  558,  682,  795,  809, -238, -232, -238,
+ /*    50 */  -232,  329,  329,  329,  329,  329,  329,  329,  329,  329,
+ /*    60 */   329,  329,  329,  329,  329,  329,  329,  329,  329,  329,
+ /*    70 */   329,  329,  329,  329,  329,  329,  329,  329,  329,  329,
+ /*    80 */   329,  329,  329,  329,  329,  329,  329,  329,  329,  557,
+ /*    90 */   712,  949,  966,  969,  971,  979, 1097, 1099, 1103, 1142,
+ /*   100 */  1144, 1169, 1172, 1201, 1203, 1228, 1241, 1250, 1253, 1255,
+ /*   110 */  1261, 1266, 1271, 1282, 1291, 1308, 1310, 1312, 1322, 1328,
+ /*   120 */  1347, 1354, 1356, 1359, 1362, 1365, 1367, 1374, 1376, 1381,
+ /*   130 */  1401, 1403, 1406, 1412, 1414, 1417, 1421, 1428, 1447, 1449,
+ /*   140 */  1453, 1462,  329,  329,  329,  329,  329,  329,  329,  329,
+ /*   150 */   329,  329,  329,  -22, -159,  475, -220,  756,   38,  501,
+ /*   160 */   841,  714,  329,  118,  337,  349,  363,  -56,  329,  329,
+ /*   170 */   329,  329, -205, -205, -205,  687, -172, -130,  -57,  790,
+ /*   180 */   397,  528, -271,  136,  596,  596,   90,  316,  522,  541,
+ /*   190 */   -37,  715,  849,  977,  628,  856,  980,  991, 1081, 1102,
+ /*   200 */  1135, 1083, -162,  208, 1258,  794,  -86,  159,   41, 1109,
+ /*   210 */   671,  852,  844,  932, 1175, 1254,  480, 1180,  100,  258,
+ /*   220 */  1265, 1268, 1216, 1287, -139,  317,  344,   63,  339,  423,
+ /*   230 */   563,  636,  676,  813,  908,  914,  950, 1078, 1084, 1098,
+ /*   240 */  1363, 1384, 1407, 1439, 1464,  411, 1527, 1534, 1535, 1537,
+ /*   250 */  1541, 1542, 1543, 1544, 1545, 1547, 1549, 1550,  990, 1164,
+ /*   260 */  1492, 1551, 1552, 1556, 1217, 1558, 1559, 1560, 1473, 1413,
+ /*   270 */  1563, 1510, 1568,  563, 1570, 1571, 1572, 1573, 1574, 1575,
+ /*   280 */  1443, 1466, 1518, 1513, 1514, 1515, 1516, 1217, 1518, 1518,
+ /*   290 */  1531, 1562, 1582, 1477, 1505, 1511, 1533, 1512, 1488, 1538,
+ /*   300 */  1509, 1517, 1546, 1519, 1557, 1489, 1565, 1564, 1578, 1586,
+ /*   310 */  1587, 1588, 1526, 1528, 1554, 1555, 1576, 1577, 1566, 1579,
+ /*   320 */  1584, 1591, 1520, 1523, 1617, 1628, 1580, 1581, 1632, 1585,
+ /*   330 */  1590, 1593, 1592, 1594, 1610, 1595, 1597, 1611, 1612, 1613,
+ /*   340 */  1614, 1652, 1655, 1615, 1598, 1600, 1616, 1596, 1622, 1619,
+ /*   350 */  1625, 1631, 1657, 1659, 1599, 1601, 1679, 1684, 1661, 1680,
+ /*   360 */  1686, 1689, 1695, 1663, 1669, 1677, 1691, 1666, 1672, 1673,
+ /*   370 */  1692, 1698, 1700, 1703, 1676, 1705, 1706, 1618, 1604, 1629,
+ /*   380 */  1643, 1704, 1711, 1621, 1626, 1648, 1665, 1697, 1699, 1656,
+ /*   390 */  1735, 1662, 1701, 1702, 1712, 1714, 1747, 1759, 1767, 1773,
+ /*   400 */  1775, 1777, 1660, 1667, 1710, 1763, 1753, 1760, 1761, 1762,
+ /*   410 */  1765, 1754, 1755, 1764, 1768, 1766, 1778,
+};
+static const YYACTIONTYPE yy_default[] = {
+ /*     0 */  1667, 1667, 1667, 1495, 1258, 1371, 1258, 1258, 1258, 1258,
+ /*    10 */  1495, 1495, 1495, 1258, 1258, 1258, 1258, 1258, 1258, 1401,
+ /*    20 */  1401, 1548, 1291, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*    30 */  1258, 1258, 1258, 1258, 1258, 1494, 1258, 1258, 1258, 1258,
+ /*    40 */  1582, 1582, 1258, 1258, 1258, 1258, 1258, 1567, 1566, 1258,
+ /*    50 */  1258, 1258, 1410, 1258, 1417, 1258, 1258, 1258, 1258, 1258,
+ /*    60 */  1496, 1497, 1258, 1258, 1258, 1258, 1547, 1549, 1512, 1424,
+ /*    70 */  1423, 1422, 1421, 1530, 1389, 1415, 1408, 1412, 1491, 1492,
+ /*    80 */  1490, 1645, 1497, 1496, 1258, 1411, 1459, 1475, 1458, 1258,
+ /*    90 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   100 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   110 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   120 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   130 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   140 */  1258, 1258, 1467, 1474, 1473, 1472, 1481, 1471, 1468, 1461,
+ /*   150 */  1460, 1462, 1463, 1282, 1258, 1279, 1333, 1258, 1258, 1258,
+ /*   160 */  1258, 1258, 1464, 1291, 1452, 1451, 1450, 1258, 1478, 1465,
+ /*   170 */  1477, 1476, 1555, 1619, 1618, 1513, 1258, 1258, 1258, 1258,
+ /*   180 */  1258, 1258, 1582, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   190 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   200 */  1258, 1258, 1258, 1258, 1258, 1391, 1582, 1582, 1258, 1291,
+ /*   210 */  1582, 1582, 1392, 1392, 1287, 1287, 1395, 1562, 1362, 1362,
+ /*   220 */  1362, 1362, 1371, 1362, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   230 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1552,
+ /*   240 */  1550, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   250 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   260 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1367, 1258,
+ /*   270 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1612,
+ /*   280 */  1258, 1525, 1347, 1367, 1367, 1367, 1367, 1369, 1348, 1346,
+ /*   290 */  1361, 1292, 1265, 1659, 1427, 1416, 1368, 1416, 1656, 1414,
+ /*   300 */  1427, 1427, 1414, 1427, 1368, 1656, 1308, 1634, 1303, 1401,
+ /*   310 */  1401, 1401, 1391, 1391, 1391, 1391, 1395, 1395, 1493, 1368,
+ /*   320 */  1361, 1258, 1659, 1659, 1377, 1377, 1658, 1658, 1377, 1513,
+ /*   330 */  1642, 1436, 1409, 1395, 1336, 1409, 1395, 1342, 1342, 1342,
+ /*   340 */  1342, 1377, 1276, 1414, 1642, 1642, 1414, 1436, 1336, 1414,
+ /*   350 */  1336, 1414, 1377, 1276, 1529, 1653, 1377, 1276, 1503, 1377,
+ /*   360 */  1276, 1377, 1276, 1503, 1334, 1334, 1334, 1323, 1258, 1258,
+ /*   370 */  1503, 1334, 1308, 1334, 1323, 1334, 1334, 1600, 1258, 1507,
+ /*   380 */  1507, 1503, 1377, 1592, 1592, 1404, 1404, 1409, 1395, 1498,
+ /*   390 */  1377, 1258, 1409, 1407, 1405, 1414, 1326, 1615, 1615, 1611,
+ /*   400 */  1611, 1611, 1664, 1664, 1562, 1627, 1291, 1291, 1291, 1291,
+ /*   410 */  1627, 1310, 1310, 1292, 1292, 1291, 1627, 1258, 1258, 1258,
+ /*   420 */  1258, 1258, 1258, 1622, 1258, 1557, 1514, 1381, 1258, 1258,
+ /*   430 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   440 */  1258, 1258, 1258, 1258, 1568, 1258, 1258, 1258, 1258, 1258,
+ /*   450 */  1258, 1258, 1258, 1258, 1258, 1258, 1441, 1258, 1261, 1559,
+ /*   460 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1418, 1419,
+ /*   470 */  1382, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1433, 1258,
+ /*   480 */  1258, 1258, 1428, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   490 */  1258, 1655, 1258, 1258, 1258, 1258, 1258, 1258, 1528, 1527,
+ /*   500 */  1258, 1258, 1379, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   510 */  1258, 1258, 1258, 1258, 1258, 1258, 1306, 1258, 1258, 1258,
+ /*   520 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   530 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   540 */  1406, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   550 */  1258, 1258, 1258, 1258, 1258, 1597, 1396, 1258, 1258, 1258,
+ /*   560 */  1258, 1646, 1258, 1258, 1258, 1258, 1356, 1258, 1258, 1258,
+ /*   570 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1638, 1350, 1442,
+ /*   580 */  1258, 1445, 1280, 1258, 1270, 1258, 1258,
+};
+/********** End of lemon-generated parsing tables *****************************/
+
+/* The next table maps tokens (terminal symbols) into fallback tokens.
+** If a construct like the following:
+**
+**      %fallback ID X Y Z.
+**
+** appears in the grammar, then ID becomes a fallback token for X, Y,
+** and Z.  Whenever one of the tokens X, Y, or Z is input to the parser
+** but it does not parse, the type of the token is changed to ID and
+** the parse is retried before an error is thrown.
+**
+** This feature can be used, for example, to cause some keywords in a language
+** to revert to identifiers if they keyword does not apply in the context where
+** it appears.
+*/
+#ifdef YYFALLBACK
+static const YYCODETYPE yyFallback[] = {
+    0,  /*          $ => nothing */
+    0,  /*       SEMI => nothing */
+   60,  /*    EXPLAIN => ID */
+   60,  /*      QUERY => ID */
+   60,  /*       PLAN => ID */
+   60,  /*      BEGIN => ID */
+    0,  /* TRANSACTION => nothing */
+   60,  /*   DEFERRED => ID */
+   60,  /*  IMMEDIATE => ID */
+   60,  /*  EXCLUSIVE => ID */
+    0,  /*     COMMIT => nothing */
+   60,  /*        END => ID */
+   60,  /*   ROLLBACK => ID */
+   60,  /*  SAVEPOINT => ID */
+   60,  /*    RELEASE => ID */
+    0,  /*         TO => nothing */
+    0,  /*      TABLE => nothing */
+    0,  /*     CREATE => nothing */
+   60,  /*         IF => ID */
+    0,  /*        NOT => nothing */
+    0,  /*     EXISTS => nothing */
+   60,  /*       TEMP => ID */
+    0,  /*         LP => nothing */
+    0,  /*         RP => nothing */
+    0,  /*         AS => nothing */
+    0,  /*      COMMA => nothing */
+   60,  /*    WITHOUT => ID */
+   60,  /*      ABORT => ID */
+   60,  /*     ACTION => ID */
+   60,  /*      AFTER => ID */
+   60,  /*    ANALYZE => ID */
+   60,  /*        ASC => ID */
+   60,  /*     ATTACH => ID */
+   60,  /*     BEFORE => ID */
+   60,  /*         BY => ID */
+   60,  /*    CASCADE => ID */
+   60,  /*       CAST => ID */
+   60,  /*   CONFLICT => ID */
+   60,  /*   DATABASE => ID */
+   60,  /*       DESC => ID */
+   60,  /*     DETACH => ID */
+   60,  /*       EACH => ID */
+   60,  /*       FAIL => ID */
+    0,  /*         OR => nothing */
+    0,  /*        AND => nothing */
+    0,  /*         IS => nothing */
+    0,  /*      ISNOT => nothing */
+   60,  /*      MATCH => ID */
+   60,  /*    LIKE_KW => ID */
+    0,  /*    BETWEEN => nothing */
+    0,  /*         IN => nothing */
+    0,  /*     ISNULL => nothing */
+    0,  /*    NOTNULL => nothing */
+    0,  /*         NE => nothing */
+    0,  /*         EQ => nothing */
+    0,  /*         GT => nothing */
+    0,  /*         LE => nothing */
+    0,  /*         LT => nothing */
+    0,  /*         GE => nothing */
+    0,  /*     ESCAPE => nothing */
+    0,  /*         ID => nothing */
+   60,  /*   COLUMNKW => ID */
+   60,  /*         DO => ID */
+   60,  /*        FOR => ID */
+   60,  /*     IGNORE => ID */
+   60,  /*  INITIALLY => ID */
+   60,  /*    INSTEAD => ID */
+   60,  /*         NO => ID */
+   60,  /*        KEY => ID */
+   60,  /*         OF => ID */
+   60,  /*     OFFSET => ID */
+   60,  /*     PRAGMA => ID */
+   60,  /*      RAISE => ID */
+   60,  /*  RECURSIVE => ID */
+   60,  /*    REPLACE => ID */
+   60,  /*   RESTRICT => ID */
+   60,  /*        ROW => ID */
+   60,  /*       ROWS => ID */
+   60,  /*    TRIGGER => ID */
+   60,  /*     VACUUM => ID */
+   60,  /*       VIEW => ID */
+   60,  /*    VIRTUAL => ID */
+   60,  /*       WITH => ID */
+   60,  /*      NULLS => ID */
+   60,  /*      FIRST => ID */
+   60,  /*       LAST => ID */
+   60,  /*    CURRENT => ID */
+   60,  /*  FOLLOWING => ID */
+   60,  /*  PARTITION => ID */
+   60,  /*  PRECEDING => ID */
+   60,  /*      RANGE => ID */
+   60,  /*  UNBOUNDED => ID */
+   60,  /*    EXCLUDE => ID */
+   60,  /*     GROUPS => ID */
+   60,  /*     OTHERS => ID */
+   60,  /*       TIES => ID */
+   60,  /*  GENERATED => ID */
+   60,  /*     ALWAYS => ID */
+   60,  /* MATERIALIZED => ID */
+   60,  /*    REINDEX => ID */
+   60,  /*     RENAME => ID */
+   60,  /*   CTIME_KW => ID */
+    0,  /*        ANY => nothing */
+    0,  /*     BITAND => nothing */
+    0,  /*      BITOR => nothing */
+    0,  /*     LSHIFT => nothing */
+    0,  /*     RSHIFT => nothing */
+    0,  /*       PLUS => nothing */
+    0,  /*      MINUS => nothing */
+    0,  /*       STAR => nothing */
+    0,  /*      SLASH => nothing */
+    0,  /*        REM => nothing */
+    0,  /*     CONCAT => nothing */
+    0,  /*        PTR => nothing */
+    0,  /*    COLLATE => nothing */
+    0,  /*     BITNOT => nothing */
+    0,  /*         ON => nothing */
+    0,  /*    INDEXED => nothing */
+    0,  /*     STRING => nothing */
+    0,  /*    JOIN_KW => nothing */
+    0,  /* CONSTRAINT => nothing */
+    0,  /*    DEFAULT => nothing */
+    0,  /*       NULL => nothing */
+    0,  /*    PRIMARY => nothing */
+    0,  /*     UNIQUE => nothing */
+    0,  /*      CHECK => nothing */
+    0,  /* REFERENCES => nothing */
+    0,  /*   AUTOINCR => nothing */
+    0,  /*     INSERT => nothing */
+    0,  /*     DELETE => nothing */
+    0,  /*     UPDATE => nothing */
+    0,  /*        SET => nothing */
+    0,  /* DEFERRABLE => nothing */
+    0,  /*    FOREIGN => nothing */
+    0,  /*       DROP => nothing */
+    0,  /*      UNION => nothing */
+    0,  /*        ALL => nothing */
+    0,  /*     EXCEPT => nothing */
+    0,  /*  INTERSECT => nothing */
+    0,  /*     SELECT => nothing */
+    0,  /*     VALUES => nothing */
+    0,  /*   DISTINCT => nothing */
+    0,  /*        DOT => nothing */
+    0,  /*       FROM => nothing */
+    0,  /*       JOIN => nothing */
+    0,  /*      USING => nothing */
+    0,  /*      ORDER => nothing */
+    0,  /*      GROUP => nothing */
+    0,  /*     HAVING => nothing */
+    0,  /*      LIMIT => nothing */
+    0,  /*      WHERE => nothing */
+    0,  /*  RETURNING => nothing */
+    0,  /*       INTO => nothing */
+    0,  /*    NOTHING => nothing */
+    0,  /*      FLOAT => nothing */
+    0,  /*       BLOB => nothing */
+    0,  /*    INTEGER => nothing */
+    0,  /*   VARIABLE => nothing */
+    0,  /*       CASE => nothing */
+    0,  /*       WHEN => nothing */
+    0,  /*       THEN => nothing */
+    0,  /*       ELSE => nothing */
+    0,  /*      INDEX => nothing */
+    0,  /*      ALTER => nothing */
+    0,  /*        ADD => nothing */
+    0,  /*     WINDOW => nothing */
+    0,  /*       OVER => nothing */
+    0,  /*     FILTER => nothing */
+    0,  /*     COLUMN => nothing */
+    0,  /* AGG_FUNCTION => nothing */
+    0,  /* AGG_COLUMN => nothing */
+    0,  /*  TRUEFALSE => nothing */
+    0,  /*   FUNCTION => nothing */
+    0,  /*      UPLUS => nothing */
+    0,  /*     UMINUS => nothing */
+    0,  /*      TRUTH => nothing */
+    0,  /*   REGISTER => nothing */
+    0,  /*     VECTOR => nothing */
+    0,  /* SELECT_COLUMN => nothing */
+    0,  /* IF_NULL_ROW => nothing */
+    0,  /*   ASTERISK => nothing */
+    0,  /*       SPAN => nothing */
+    0,  /*      ERROR => nothing */
+    0,  /*    QNUMBER => nothing */
+    0,  /*      SPACE => nothing */
+    0,  /*    COMMENT => nothing */
+    0,  /*    ILLEGAL => nothing */
+};
+#endif /* YYFALLBACK */
+
+/* The following structure represents a single element of the
+** parser's stack.  Information stored includes:
+**
+**   +  The state number for the parser at this level of the stack.
+**
+**   +  The value of the token stored at this level of the stack.
+**      (In other words, the "major" token.)
+**
+**   +  The semantic value stored at this level of the stack.  This is
+**      the information used by the action routines in the grammar.
+**      It is sometimes called the "minor" token.
+**
+** After the "shift" half of a SHIFTREDUCE action, the stateno field
+** actually contains the reduce action for the second half of the
+** SHIFTREDUCE.
+*/
+struct yyStackEntry {
+  YYACTIONTYPE stateno;  /* The state-number, or reduce action in SHIFTREDUCE */
+  YYCODETYPE major;      /* The major token value.  This is the code
+                         ** number for the token at this stack level */
+  YYMINORTYPE minor;     /* The user-supplied minor token value.  This
+                         ** is the value of the token  */
+};
+typedef struct yyStackEntry yyStackEntry;
+
+/* The state of the parser is completely contained in an instance of
+** the following structure */
+struct yyParser {
+  yyStackEntry *yytos;          /* Pointer to top element of the stack */
+#ifdef YYTRACKMAXSTACKDEPTH
+  int yyhwm;                    /* High-water mark of the stack */
+#endif
+#ifndef YYNOERRORRECOVERY
+  int yyerrcnt;                 /* Shifts left before out of the error */
+#endif
+  sqlite3ParserARG_SDECL                /* A place to hold %extra_argument */
+  sqlite3ParserCTX_SDECL                /* A place to hold %extra_context */
+  yyStackEntry *yystackEnd;           /* Last entry in the stack */
+  yyStackEntry *yystack;              /* The parser stack */
+  yyStackEntry yystk0[YYSTACKDEPTH];  /* Initial stack space */
+};
+typedef struct yyParser yyParser;
+
+/* #include <assert.h> */
+#ifndef NDEBUG
+/* #include <stdio.h> */
+static FILE *yyTraceFILE = 0;
+static char *yyTracePrompt = 0;
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/*
+** Turn parser tracing on by giving a stream to which to write the trace
+** and a prompt to preface each trace message.  Tracing is turned off
+** by making either argument NULL
+**
+** Inputs:
+** <ul>
+** <li> A FILE* to which trace output should be written.
+**      If NULL, then tracing is turned off.
+** <li> A prefix string written at the beginning of every
+**      line of trace output.  If NULL, then tracing is
+**      turned off.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+SQLITE_PRIVATE void sqlite3ParserTrace(FILE *TraceFILE, char *zTracePrompt){
+  yyTraceFILE = TraceFILE;
+  yyTracePrompt = zTracePrompt;
+  if( yyTraceFILE==0 ) yyTracePrompt = 0;
+  else if( yyTracePrompt==0 ) yyTraceFILE = 0;
+}
+#endif /* NDEBUG */
+
+#if defined(YYCOVERAGE) || !defined(NDEBUG)
+/* For tracing shifts, the names of all terminals and nonterminals
+** are required.  The following table supplies these names */
+static const char *const yyTokenName[] = {
+  /*    0 */ "$",
+  /*    1 */ "SEMI",
+  /*    2 */ "EXPLAIN",
+  /*    3 */ "QUERY",
+  /*    4 */ "PLAN",
+  /*    5 */ "BEGIN",
+  /*    6 */ "TRANSACTION",
+  /*    7 */ "DEFERRED",
+  /*    8 */ "IMMEDIATE",
+  /*    9 */ "EXCLUSIVE",
+  /*   10 */ "COMMIT",
+  /*   11 */ "END",
+  /*   12 */ "ROLLBACK",
+  /*   13 */ "SAVEPOINT",
+  /*   14 */ "RELEASE",
+  /*   15 */ "TO",
+  /*   16 */ "TABLE",
+  /*   17 */ "CREATE",
+  /*   18 */ "IF",
+  /*   19 */ "NOT",
+  /*   20 */ "EXISTS",
+  /*   21 */ "TEMP",
+  /*   22 */ "LP",
+  /*   23 */ "RP",
+  /*   24 */ "AS",
+  /*   25 */ "COMMA",
+  /*   26 */ "WITHOUT",
+  /*   27 */ "ABORT",
+  /*   28 */ "ACTION",
+  /*   29 */ "AFTER",
+  /*   30 */ "ANALYZE",
+  /*   31 */ "ASC",
+  /*   32 */ "ATTACH",
+  /*   33 */ "BEFORE",
+  /*   34 */ "BY",
+  /*   35 */ "CASCADE",
+  /*   36 */ "CAST",
+  /*   37 */ "CONFLICT",
+  /*   38 */ "DATABASE",
+  /*   39 */ "DESC",
+  /*   40 */ "DETACH",
+  /*   41 */ "EACH",
+  /*   42 */ "FAIL",
+  /*   43 */ "OR",
+  /*   44 */ "AND",
+  /*   45 */ "IS",
+  /*   46 */ "ISNOT",
+  /*   47 */ "MATCH",
+  /*   48 */ "LIKE_KW",
+  /*   49 */ "BETWEEN",
+  /*   50 */ "IN",
+  /*   51 */ "ISNULL",
+  /*   52 */ "NOTNULL",
+  /*   53 */ "NE",
+  /*   54 */ "EQ",
+  /*   55 */ "GT",
+  /*   56 */ "LE",
+  /*   57 */ "LT",
+  /*   58 */ "GE",
+  /*   59 */ "ESCAPE",
+  /*   60 */ "ID",
+  /*   61 */ "COLUMNKW",
+  /*   62 */ "DO",
+  /*   63 */ "FOR",
+  /*   64 */ "IGNORE",
+  /*   65 */ "INITIALLY",
+  /*   66 */ "INSTEAD",
+  /*   67 */ "NO",
+  /*   68 */ "KEY",
+  /*   69 */ "OF",
+  /*   70 */ "OFFSET",
+  /*   71 */ "PRAGMA",
+  /*   72 */ "RAISE",
+  /*   73 */ "RECURSIVE",
+  /*   74 */ "REPLACE",
+  /*   75 */ "RESTRICT",
+  /*   76 */ "ROW",
+  /*   77 */ "ROWS",
+  /*   78 */ "TRIGGER",
+  /*   79 */ "VACUUM",
+  /*   80 */ "VIEW",
+  /*   81 */ "VIRTUAL",
+  /*   82 */ "WITH",
+  /*   83 */ "NULLS",
+  /*   84 */ "FIRST",
+  /*   85 */ "LAST",
+  /*   86 */ "CURRENT",
+  /*   87 */ "FOLLOWING",
+  /*   88 */ "PARTITION",
+  /*   89 */ "PRECEDING",
+  /*   90 */ "RANGE",
+  /*   91 */ "UNBOUNDED",
+  /*   92 */ "EXCLUDE",
+  /*   93 */ "GROUPS",
+  /*   94 */ "OTHERS",
+  /*   95 */ "TIES",
+  /*   96 */ "GENERATED",
+  /*   97 */ "ALWAYS",
+  /*   98 */ "MATERIALIZED",
+  /*   99 */ "REINDEX",
+  /*  100 */ "RENAME",
+  /*  101 */ "CTIME_KW",
+  /*  102 */ "ANY",
+  /*  103 */ "BITAND",
+  /*  104 */ "BITOR",
+  /*  105 */ "LSHIFT",
+  /*  106 */ "RSHIFT",
+  /*  107 */ "PLUS",
+  /*  108 */ "MINUS",
+  /*  109 */ "STAR",
+  /*  110 */ "SLASH",
+  /*  111 */ "REM",
+  /*  112 */ "CONCAT",
+  /*  113 */ "PTR",
+  /*  114 */ "COLLATE",
+  /*  115 */ "BITNOT",
+  /*  116 */ "ON",
+  /*  117 */ "INDEXED",
+  /*  118 */ "STRING",
+  /*  119 */ "JOIN_KW",
+  /*  120 */ "CONSTRAINT",
+  /*  121 */ "DEFAULT",
+  /*  122 */ "NULL",
+  /*  123 */ "PRIMARY",
+  /*  124 */ "UNIQUE",
+  /*  125 */ "CHECK",
+  /*  126 */ "REFERENCES",
+  /*  127 */ "AUTOINCR",
+  /*  128 */ "INSERT",
+  /*  129 */ "DELETE",
+  /*  130 */ "UPDATE",
+  /*  131 */ "SET",
+  /*  132 */ "DEFERRABLE",
+  /*  133 */ "FOREIGN",
+  /*  134 */ "DROP",
+  /*  135 */ "UNION",
+  /*  136 */ "ALL",
+  /*  137 */ "EXCEPT",
+  /*  138 */ "INTERSECT",
+  /*  139 */ "SELECT",
+  /*  140 */ "VALUES",
+  /*  141 */ "DISTINCT",
+  /*  142 */ "DOT",
+  /*  143 */ "FROM",
+  /*  144 */ "JOIN",
+  /*  145 */ "USING",
+  /*  146 */ "ORDER",
+  /*  147 */ "GROUP",
+  /*  148 */ "HAVING",
+  /*  149 */ "LIMIT",
+  /*  150 */ "WHERE",
+  /*  151 */ "RETURNING",
+  /*  152 */ "INTO",
+  /*  153 */ "NOTHING",
+  /*  154 */ "FLOAT",
+  /*  155 */ "BLOB",
+  /*  156 */ "INTEGER",
+  /*  157 */ "VARIABLE",
+  /*  158 */ "CASE",
+  /*  159 */ "WHEN",
+  /*  160 */ "THEN",
+  /*  161 */ "ELSE",
+  /*  162 */ "INDEX",
+  /*  163 */ "ALTER",
+  /*  164 */ "ADD",
+  /*  165 */ "WINDOW",
+  /*  166 */ "OVER",
+  /*  167 */ "FILTER",
+  /*  168 */ "COLUMN",
+  /*  169 */ "AGG_FUNCTION",
+  /*  170 */ "AGG_COLUMN",
+  /*  171 */ "TRUEFALSE",
+  /*  172 */ "FUNCTION",
+  /*  173 */ "UPLUS",
+  /*  174 */ "UMINUS",
+  /*  175 */ "TRUTH",
+  /*  176 */ "REGISTER",
+  /*  177 */ "VECTOR",
+  /*  178 */ "SELECT_COLUMN",
+  /*  179 */ "IF_NULL_ROW",
+  /*  180 */ "ASTERISK",
+  /*  181 */ "SPAN",
+  /*  182 */ "ERROR",
+  /*  183 */ "QNUMBER",
+  /*  184 */ "SPACE",
+  /*  185 */ "COMMENT",
+  /*  186 */ "ILLEGAL",
+  /*  187 */ "input",
+  /*  188 */ "cmdlist",
+  /*  189 */ "ecmd",
+  /*  190 */ "cmdx",
+  /*  191 */ "explain",
+  /*  192 */ "cmd",
+  /*  193 */ "transtype",
+  /*  194 */ "trans_opt",
+  /*  195 */ "nm",
+  /*  196 */ "savepoint_opt",
+  /*  197 */ "create_table",
+  /*  198 */ "create_table_args",
+  /*  199 */ "createkw",
+  /*  200 */ "temp",
+  /*  201 */ "ifnotexists",
+  /*  202 */ "dbnm",
+  /*  203 */ "columnlist",
+  /*  204 */ "conslist_opt",
+  /*  205 */ "table_option_set",
+  /*  206 */ "select",
+  /*  207 */ "table_option",
+  /*  208 */ "columnname",
+  /*  209 */ "carglist",
+  /*  210 */ "typetoken",
+  /*  211 */ "typename",
+  /*  212 */ "signed",
+  /*  213 */ "plus_num",
+  /*  214 */ "minus_num",
+  /*  215 */ "scanpt",
+  /*  216 */ "scantok",
+  /*  217 */ "ccons",
+  /*  218 */ "term",
+  /*  219 */ "expr",
+  /*  220 */ "onconf",
+  /*  221 */ "sortorder",
+  /*  222 */ "autoinc",
+  /*  223 */ "eidlist_opt",
+  /*  224 */ "refargs",
+  /*  225 */ "defer_subclause",
+  /*  226 */ "generated",
+  /*  227 */ "refarg",
+  /*  228 */ "refact",
+  /*  229 */ "init_deferred_pred_opt",
+  /*  230 */ "conslist",
+  /*  231 */ "tconscomma",
+  /*  232 */ "tcons",
+  /*  233 */ "sortlist",
+  /*  234 */ "eidlist",
+  /*  235 */ "defer_subclause_opt",
+  /*  236 */ "orconf",
+  /*  237 */ "resolvetype",
+  /*  238 */ "raisetype",
+  /*  239 */ "ifexists",
+  /*  240 */ "fullname",
+  /*  241 */ "selectnowith",
+  /*  242 */ "oneselect",
+  /*  243 */ "wqlist",
+  /*  244 */ "multiselect_op",
+  /*  245 */ "distinct",
+  /*  246 */ "selcollist",
+  /*  247 */ "from",
+  /*  248 */ "where_opt",
+  /*  249 */ "groupby_opt",
+  /*  250 */ "having_opt",
+  /*  251 */ "orderby_opt",
+  /*  252 */ "limit_opt",
+  /*  253 */ "window_clause",
+  /*  254 */ "values",
+  /*  255 */ "nexprlist",
+  /*  256 */ "mvalues",
+  /*  257 */ "sclp",
+  /*  258 */ "as",
+  /*  259 */ "seltablist",
+  /*  260 */ "stl_prefix",
+  /*  261 */ "joinop",
+  /*  262 */ "on_using",
+  /*  263 */ "indexed_by",
+  /*  264 */ "exprlist",
+  /*  265 */ "xfullname",
+  /*  266 */ "idlist",
+  /*  267 */ "indexed_opt",
+  /*  268 */ "nulls",
+  /*  269 */ "with",
+  /*  270 */ "where_opt_ret",
+  /*  271 */ "setlist",
+  /*  272 */ "insert_cmd",
+  /*  273 */ "idlist_opt",
+  /*  274 */ "upsert",
+  /*  275 */ "returning",
+  /*  276 */ "filter_over",
+  /*  277 */ "likeop",
+  /*  278 */ "between_op",
+  /*  279 */ "in_op",
+  /*  280 */ "paren_exprlist",
+  /*  281 */ "case_operand",
+  /*  282 */ "case_exprlist",
+  /*  283 */ "case_else",
+  /*  284 */ "uniqueflag",
+  /*  285 */ "collate",
+  /*  286 */ "vinto",
+  /*  287 */ "nmnum",
+  /*  288 */ "trigger_decl",
+  /*  289 */ "trigger_cmd_list",
+  /*  290 */ "trigger_time",
+  /*  291 */ "trigger_event",
+  /*  292 */ "foreach_clause",
+  /*  293 */ "when_clause",
+  /*  294 */ "trigger_cmd",
+  /*  295 */ "trnm",
+  /*  296 */ "tridxby",
+  /*  297 */ "database_kw_opt",
+  /*  298 */ "key_opt",
+  /*  299 */ "add_column_fullname",
+  /*  300 */ "kwcolumn_opt",
+  /*  301 */ "create_vtab",
+  /*  302 */ "vtabarglist",
+  /*  303 */ "vtabarg",
+  /*  304 */ "vtabargtoken",
+  /*  305 */ "lp",
+  /*  306 */ "anylist",
+  /*  307 */ "wqitem",
+  /*  308 */ "wqas",
+  /*  309 */ "withnm",
+  /*  310 */ "windowdefn_list",
+  /*  311 */ "windowdefn",
+  /*  312 */ "window",
+  /*  313 */ "frame_opt",
+  /*  314 */ "part_opt",
+  /*  315 */ "filter_clause",
+  /*  316 */ "over_clause",
+  /*  317 */ "range_or_rows",
+  /*  318 */ "frame_bound",
+  /*  319 */ "frame_bound_s",
+  /*  320 */ "frame_bound_e",
+  /*  321 */ "frame_exclude_opt",
+  /*  322 */ "frame_exclude",
+};
+#endif /* defined(YYCOVERAGE) || !defined(NDEBUG) */
+
+#ifndef NDEBUG
+/* For tracing reduce actions, the names of all rules are required.
+*/
+static const char *const yyRuleName[] = {
+ /*   0 */ "explain ::= EXPLAIN",
+ /*   1 */ "explain ::= EXPLAIN QUERY PLAN",
+ /*   2 */ "cmdx ::= cmd",
+ /*   3 */ "cmd ::= BEGIN transtype trans_opt",
+ /*   4 */ "transtype ::=",
+ /*   5 */ "transtype ::= DEFERRED",
+ /*   6 */ "transtype ::= IMMEDIATE",
+ /*   7 */ "transtype ::= EXCLUSIVE",
+ /*   8 */ "cmd ::= COMMIT|END trans_opt",
+ /*   9 */ "cmd ::= ROLLBACK trans_opt",
+ /*  10 */ "cmd ::= SAVEPOINT nm",
+ /*  11 */ "cmd ::= RELEASE savepoint_opt nm",
+ /*  12 */ "cmd ::= ROLLBACK trans_opt TO savepoint_opt nm",
+ /*  13 */ "create_table ::= createkw temp TABLE ifnotexists nm dbnm",
+ /*  14 */ "createkw ::= CREATE",
+ /*  15 */ "ifnotexists ::=",
+ /*  16 */ "ifnotexists ::= IF NOT EXISTS",
+ /*  17 */ "temp ::= TEMP",
+ /*  18 */ "temp ::=",
+ /*  19 */ "create_table_args ::= LP columnlist conslist_opt RP table_option_set",
+ /*  20 */ "create_table_args ::= AS select",
+ /*  21 */ "table_option_set ::=",
+ /*  22 */ "table_option_set ::= table_option_set COMMA table_option",
+ /*  23 */ "table_option ::= WITHOUT nm",
+ /*  24 */ "table_option ::= nm",
+ /*  25 */ "columnname ::= nm typetoken",
+ /*  26 */ "typetoken ::=",
+ /*  27 */ "typetoken ::= typename LP signed RP",
+ /*  28 */ "typetoken ::= typename LP signed COMMA signed RP",
+ /*  29 */ "typename ::= typename ID|STRING",
+ /*  30 */ "scanpt ::=",
+ /*  31 */ "scantok ::=",
+ /*  32 */ "ccons ::= CONSTRAINT nm",
+ /*  33 */ "ccons ::= DEFAULT scantok term",
+ /*  34 */ "ccons ::= DEFAULT LP expr RP",
+ /*  35 */ "ccons ::= DEFAULT PLUS scantok term",
+ /*  36 */ "ccons ::= DEFAULT MINUS scantok term",
+ /*  37 */ "ccons ::= DEFAULT scantok ID|INDEXED",
+ /*  38 */ "ccons ::= NOT NULL onconf",
+ /*  39 */ "ccons ::= PRIMARY KEY sortorder onconf autoinc",
+ /*  40 */ "ccons ::= UNIQUE onconf",
+ /*  41 */ "ccons ::= CHECK LP expr RP",
+ /*  42 */ "ccons ::= REFERENCES nm eidlist_opt refargs",
+ /*  43 */ "ccons ::= defer_subclause",
+ /*  44 */ "ccons ::= COLLATE ID|STRING",
+ /*  45 */ "generated ::= LP expr RP",
+ /*  46 */ "generated ::= LP expr RP ID",
+ /*  47 */ "autoinc ::=",
+ /*  48 */ "autoinc ::= AUTOINCR",
+ /*  49 */ "refargs ::=",
+ /*  50 */ "refargs ::= refargs refarg",
+ /*  51 */ "refarg ::= MATCH nm",
+ /*  52 */ "refarg ::= ON INSERT refact",
+ /*  53 */ "refarg ::= ON DELETE refact",
+ /*  54 */ "refarg ::= ON UPDATE refact",
+ /*  55 */ "refact ::= SET NULL",
+ /*  56 */ "refact ::= SET DEFAULT",
+ /*  57 */ "refact ::= CASCADE",
+ /*  58 */ "refact ::= RESTRICT",
+ /*  59 */ "refact ::= NO ACTION",
+ /*  60 */ "defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt",
+ /*  61 */ "defer_subclause ::= DEFERRABLE init_deferred_pred_opt",
+ /*  62 */ "init_deferred_pred_opt ::=",
+ /*  63 */ "init_deferred_pred_opt ::= INITIALLY DEFERRED",
+ /*  64 */ "init_deferred_pred_opt ::= INITIALLY IMMEDIATE",
+ /*  65 */ "conslist_opt ::=",
+ /*  66 */ "tconscomma ::= COMMA",
+ /*  67 */ "tcons ::= CONSTRAINT nm",
+ /*  68 */ "tcons ::= PRIMARY KEY LP sortlist autoinc RP onconf",
+ /*  69 */ "tcons ::= UNIQUE LP sortlist RP onconf",
+ /*  70 */ "tcons ::= CHECK LP expr RP onconf",
+ /*  71 */ "tcons ::= FOREIGN KEY LP eidlist RP REFERENCES nm eidlist_opt refargs defer_subclause_opt",
+ /*  72 */ "defer_subclause_opt ::=",
+ /*  73 */ "onconf ::=",
+ /*  74 */ "onconf ::= ON CONFLICT resolvetype",
+ /*  75 */ "orconf ::=",
+ /*  76 */ "orconf ::= OR resolvetype",
+ /*  77 */ "resolvetype ::= IGNORE",
+ /*  78 */ "resolvetype ::= REPLACE",
+ /*  79 */ "cmd ::= DROP TABLE ifexists fullname",
+ /*  80 */ "ifexists ::= IF EXISTS",
+ /*  81 */ "ifexists ::=",
+ /*  82 */ "cmd ::= createkw temp VIEW ifnotexists nm dbnm eidlist_opt AS select",
+ /*  83 */ "cmd ::= DROP VIEW ifexists fullname",
+ /*  84 */ "cmd ::= select",
+ /*  85 */ "select ::= WITH wqlist selectnowith",
+ /*  86 */ "select ::= WITH RECURSIVE wqlist selectnowith",
+ /*  87 */ "select ::= selectnowith",
+ /*  88 */ "selectnowith ::= selectnowith multiselect_op oneselect",
+ /*  89 */ "multiselect_op ::= UNION",
+ /*  90 */ "multiselect_op ::= UNION ALL",
+ /*  91 */ "multiselect_op ::= EXCEPT|INTERSECT",
+ /*  92 */ "oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt",
+ /*  93 */ "oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt window_clause orderby_opt limit_opt",
+ /*  94 */ "values ::= VALUES LP nexprlist RP",
+ /*  95 */ "oneselect ::= mvalues",
+ /*  96 */ "mvalues ::= values COMMA LP nexprlist RP",
+ /*  97 */ "mvalues ::= mvalues COMMA LP nexprlist RP",
+ /*  98 */ "distinct ::= DISTINCT",
+ /*  99 */ "distinct ::= ALL",
+ /* 100 */ "distinct ::=",
+ /* 101 */ "sclp ::=",
+ /* 102 */ "selcollist ::= sclp scanpt expr scanpt as",
+ /* 103 */ "selcollist ::= sclp scanpt STAR",
+ /* 104 */ "selcollist ::= sclp scanpt nm DOT STAR",
+ /* 105 */ "as ::= AS nm",
+ /* 106 */ "as ::=",
+ /* 107 */ "from ::=",
+ /* 108 */ "from ::= FROM seltablist",
+ /* 109 */ "stl_prefix ::= seltablist joinop",
+ /* 110 */ "stl_prefix ::=",
+ /* 111 */ "seltablist ::= stl_prefix nm dbnm as on_using",
+ /* 112 */ "seltablist ::= stl_prefix nm dbnm as indexed_by on_using",
+ /* 113 */ "seltablist ::= stl_prefix nm dbnm LP exprlist RP as on_using",
+ /* 114 */ "seltablist ::= stl_prefix LP select RP as on_using",
+ /* 115 */ "seltablist ::= stl_prefix LP seltablist RP as on_using",
+ /* 116 */ "dbnm ::=",
+ /* 117 */ "dbnm ::= DOT nm",
+ /* 118 */ "fullname ::= nm",
+ /* 119 */ "fullname ::= nm DOT nm",
+ /* 120 */ "xfullname ::= nm",
+ /* 121 */ "xfullname ::= nm DOT nm",
+ /* 122 */ "xfullname ::= nm DOT nm AS nm",
+ /* 123 */ "xfullname ::= nm AS nm",
+ /* 124 */ "joinop ::= COMMA|JOIN",
+ /* 125 */ "joinop ::= JOIN_KW JOIN",
+ /* 126 */ "joinop ::= JOIN_KW nm JOIN",
+ /* 127 */ "joinop ::= JOIN_KW nm nm JOIN",
+ /* 128 */ "on_using ::= ON expr",
+ /* 129 */ "on_using ::= USING LP idlist RP",
+ /* 130 */ "on_using ::=",
+ /* 131 */ "indexed_opt ::=",
+ /* 132 */ "indexed_by ::= INDEXED BY nm",
+ /* 133 */ "indexed_by ::= NOT INDEXED",
+ /* 134 */ "orderby_opt ::=",
+ /* 135 */ "orderby_opt ::= ORDER BY sortlist",
+ /* 136 */ "sortlist ::= sortlist COMMA expr sortorder nulls",
+ /* 137 */ "sortlist ::= expr sortorder nulls",
+ /* 138 */ "sortorder ::= ASC",
+ /* 139 */ "sortorder ::= DESC",
+ /* 140 */ "sortorder ::=",
+ /* 141 */ "nulls ::= NULLS FIRST",
+ /* 142 */ "nulls ::= NULLS LAST",
+ /* 143 */ "nulls ::=",
+ /* 144 */ "groupby_opt ::=",
+ /* 145 */ "groupby_opt ::= GROUP BY nexprlist",
+ /* 146 */ "having_opt ::=",
+ /* 147 */ "having_opt ::= HAVING expr",
+ /* 148 */ "limit_opt ::=",
+ /* 149 */ "limit_opt ::= LIMIT expr",
+ /* 150 */ "limit_opt ::= LIMIT expr OFFSET expr",
+ /* 151 */ "limit_opt ::= LIMIT expr COMMA expr",
+ /* 152 */ "cmd ::= with DELETE FROM xfullname indexed_opt where_opt_ret orderby_opt limit_opt",
+ /* 153 */ "where_opt ::=",
+ /* 154 */ "where_opt ::= WHERE expr",
+ /* 155 */ "where_opt_ret ::=",
+ /* 156 */ "where_opt_ret ::= WHERE expr",
+ /* 157 */ "where_opt_ret ::= RETURNING selcollist",
+ /* 158 */ "where_opt_ret ::= WHERE expr RETURNING selcollist",
+ /* 159 */ "cmd ::= with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret orderby_opt limit_opt",
+ /* 160 */ "setlist ::= setlist COMMA nm EQ expr",
+ /* 161 */ "setlist ::= setlist COMMA LP idlist RP EQ expr",
+ /* 162 */ "setlist ::= nm EQ expr",
+ /* 163 */ "setlist ::= LP idlist RP EQ expr",
+ /* 164 */ "cmd ::= with insert_cmd INTO xfullname idlist_opt select upsert",
+ /* 165 */ "cmd ::= with insert_cmd INTO xfullname idlist_opt DEFAULT VALUES returning",
+ /* 166 */ "upsert ::=",
+ /* 167 */ "upsert ::= RETURNING selcollist",
+ /* 168 */ "upsert ::= ON CONFLICT LP sortlist RP where_opt DO UPDATE SET setlist where_opt upsert",
+ /* 169 */ "upsert ::= ON CONFLICT LP sortlist RP where_opt DO NOTHING upsert",
+ /* 170 */ "upsert ::= ON CONFLICT DO NOTHING returning",
+ /* 171 */ "upsert ::= ON CONFLICT DO UPDATE SET setlist where_opt returning",
+ /* 172 */ "returning ::= RETURNING selcollist",
+ /* 173 */ "insert_cmd ::= INSERT orconf",
+ /* 174 */ "insert_cmd ::= REPLACE",
+ /* 175 */ "idlist_opt ::=",
+ /* 176 */ "idlist_opt ::= LP idlist RP",
+ /* 177 */ "idlist ::= idlist COMMA nm",
+ /* 178 */ "idlist ::= nm",
+ /* 179 */ "expr ::= LP expr RP",
+ /* 180 */ "expr ::= ID|INDEXED|JOIN_KW",
+ /* 181 */ "expr ::= nm DOT nm",
+ /* 182 */ "expr ::= nm DOT nm DOT nm",
+ /* 183 */ "term ::= NULL|FLOAT|BLOB",
+ /* 184 */ "term ::= STRING",
+ /* 185 */ "term ::= INTEGER",
+ /* 186 */ "expr ::= VARIABLE",
+ /* 187 */ "expr ::= expr COLLATE ID|STRING",
+ /* 188 */ "expr ::= CAST LP expr AS typetoken RP",
+ /* 189 */ "expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP",
+ /* 190 */ "expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP",
+ /* 191 */ "expr ::= ID|INDEXED|JOIN_KW LP STAR RP",
+ /* 192 */ "expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP filter_over",
+ /* 193 */ "expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP filter_over",
+ /* 194 */ "expr ::= ID|INDEXED|JOIN_KW LP STAR RP filter_over",
+ /* 195 */ "term ::= CTIME_KW",
+ /* 196 */ "expr ::= LP nexprlist COMMA expr RP",
+ /* 197 */ "expr ::= expr AND expr",
+ /* 198 */ "expr ::= expr OR expr",
+ /* 199 */ "expr ::= expr LT|GT|GE|LE expr",
+ /* 200 */ "expr ::= expr EQ|NE expr",
+ /* 201 */ "expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr",
+ /* 202 */ "expr ::= expr PLUS|MINUS expr",
+ /* 203 */ "expr ::= expr STAR|SLASH|REM expr",
+ /* 204 */ "expr ::= expr CONCAT expr",
+ /* 205 */ "likeop ::= NOT LIKE_KW|MATCH",
+ /* 206 */ "expr ::= expr likeop expr",
+ /* 207 */ "expr ::= expr likeop expr ESCAPE expr",
+ /* 208 */ "expr ::= expr ISNULL|NOTNULL",
+ /* 209 */ "expr ::= expr NOT NULL",
+ /* 210 */ "expr ::= expr IS expr",
+ /* 211 */ "expr ::= expr IS NOT expr",
+ /* 212 */ "expr ::= expr IS NOT DISTINCT FROM expr",
+ /* 213 */ "expr ::= expr IS DISTINCT FROM expr",
+ /* 214 */ "expr ::= NOT expr",
+ /* 215 */ "expr ::= BITNOT expr",
+ /* 216 */ "expr ::= PLUS|MINUS expr",
+ /* 217 */ "expr ::= expr PTR expr",
+ /* 218 */ "between_op ::= BETWEEN",
+ /* 219 */ "between_op ::= NOT BETWEEN",
+ /* 220 */ "expr ::= expr between_op expr AND expr",
+ /* 221 */ "in_op ::= IN",
+ /* 222 */ "in_op ::= NOT IN",
+ /* 223 */ "expr ::= expr in_op LP exprlist RP",
+ /* 224 */ "expr ::= LP select RP",
+ /* 225 */ "expr ::= expr in_op LP select RP",
+ /* 226 */ "expr ::= expr in_op nm dbnm paren_exprlist",
+ /* 227 */ "expr ::= EXISTS LP select RP",
+ /* 228 */ "expr ::= CASE case_operand case_exprlist case_else END",
+ /* 229 */ "case_exprlist ::= case_exprlist WHEN expr THEN expr",
+ /* 230 */ "case_exprlist ::= WHEN expr THEN expr",
+ /* 231 */ "case_else ::= ELSE expr",
+ /* 232 */ "case_else ::=",
+ /* 233 */ "case_operand ::=",
+ /* 234 */ "exprlist ::=",
+ /* 235 */ "nexprlist ::= nexprlist COMMA expr",
+ /* 236 */ "nexprlist ::= expr",
+ /* 237 */ "paren_exprlist ::=",
+ /* 238 */ "paren_exprlist ::= LP exprlist RP",
+ /* 239 */ "cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP sortlist RP where_opt",
+ /* 240 */ "uniqueflag ::= UNIQUE",
+ /* 241 */ "uniqueflag ::=",
+ /* 242 */ "eidlist_opt ::=",
+ /* 243 */ "eidlist_opt ::= LP eidlist RP",
+ /* 244 */ "eidlist ::= eidlist COMMA nm collate sortorder",
+ /* 245 */ "eidlist ::= nm collate sortorder",
+ /* 246 */ "collate ::=",
+ /* 247 */ "collate ::= COLLATE ID|STRING",
+ /* 248 */ "cmd ::= DROP INDEX ifexists fullname",
+ /* 249 */ "cmd ::= VACUUM vinto",
+ /* 250 */ "cmd ::= VACUUM nm vinto",
+ /* 251 */ "vinto ::= INTO expr",
+ /* 252 */ "vinto ::=",
+ /* 253 */ "cmd ::= PRAGMA nm dbnm",
+ /* 254 */ "cmd ::= PRAGMA nm dbnm EQ nmnum",
+ /* 255 */ "cmd ::= PRAGMA nm dbnm LP nmnum RP",
+ /* 256 */ "cmd ::= PRAGMA nm dbnm EQ minus_num",
+ /* 257 */ "cmd ::= PRAGMA nm dbnm LP minus_num RP",
+ /* 258 */ "plus_num ::= PLUS INTEGER|FLOAT",
+ /* 259 */ "minus_num ::= MINUS INTEGER|FLOAT",
+ /* 260 */ "cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END",
+ /* 261 */ "trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause",
+ /* 262 */ "trigger_time ::= BEFORE|AFTER",
+ /* 263 */ "trigger_time ::= INSTEAD OF",
+ /* 264 */ "trigger_time ::=",
+ /* 265 */ "trigger_event ::= DELETE|INSERT",
+ /* 266 */ "trigger_event ::= UPDATE",
+ /* 267 */ "trigger_event ::= UPDATE OF idlist",
+ /* 268 */ "when_clause ::=",
+ /* 269 */ "when_clause ::= WHEN expr",
+ /* 270 */ "trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI",
+ /* 271 */ "trigger_cmd_list ::= trigger_cmd SEMI",
+ /* 272 */ "trnm ::= nm DOT nm",
+ /* 273 */ "tridxby ::= INDEXED BY nm",
+ /* 274 */ "tridxby ::= NOT INDEXED",
+ /* 275 */ "trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist from where_opt scanpt",
+ /* 276 */ "trigger_cmd ::= scanpt insert_cmd INTO trnm idlist_opt select upsert scanpt",
+ /* 277 */ "trigger_cmd ::= DELETE FROM trnm tridxby where_opt scanpt",
+ /* 278 */ "trigger_cmd ::= scanpt select scanpt",
+ /* 279 */ "expr ::= RAISE LP IGNORE RP",
+ /* 280 */ "expr ::= RAISE LP raisetype COMMA expr RP",
+ /* 281 */ "raisetype ::= ROLLBACK",
+ /* 282 */ "raisetype ::= ABORT",
+ /* 283 */ "raisetype ::= FAIL",
+ /* 284 */ "cmd ::= DROP TRIGGER ifexists fullname",
+ /* 285 */ "cmd ::= ATTACH database_kw_opt expr AS expr key_opt",
+ /* 286 */ "cmd ::= DETACH database_kw_opt expr",
+ /* 287 */ "key_opt ::=",
+ /* 288 */ "key_opt ::= KEY expr",
+ /* 289 */ "cmd ::= REINDEX",
+ /* 290 */ "cmd ::= REINDEX nm dbnm",
+ /* 291 */ "cmd ::= ANALYZE",
+ /* 292 */ "cmd ::= ANALYZE nm dbnm",
+ /* 293 */ "cmd ::= ALTER TABLE fullname RENAME TO nm",
+ /* 294 */ "cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt columnname carglist",
+ /* 295 */ "cmd ::= ALTER TABLE fullname DROP kwcolumn_opt nm",
+ /* 296 */ "add_column_fullname ::= fullname",
+ /* 297 */ "cmd ::= ALTER TABLE fullname RENAME kwcolumn_opt nm TO nm",
+ /* 298 */ "cmd ::= create_vtab",
+ /* 299 */ "cmd ::= create_vtab LP vtabarglist RP",
+ /* 300 */ "create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm",
+ /* 301 */ "vtabarg ::=",
+ /* 302 */ "vtabargtoken ::= ANY",
+ /* 303 */ "vtabargtoken ::= lp anylist RP",
+ /* 304 */ "lp ::= LP",
+ /* 305 */ "with ::= WITH wqlist",
+ /* 306 */ "with ::= WITH RECURSIVE wqlist",
+ /* 307 */ "wqas ::= AS",
+ /* 308 */ "wqas ::= AS MATERIALIZED",
+ /* 309 */ "wqas ::= AS NOT MATERIALIZED",
+ /* 310 */ "wqitem ::= withnm eidlist_opt wqas LP select RP",
+ /* 311 */ "withnm ::= nm",
+ /* 312 */ "wqlist ::= wqitem",
+ /* 313 */ "wqlist ::= wqlist COMMA wqitem",
+ /* 314 */ "windowdefn_list ::= windowdefn_list COMMA windowdefn",
+ /* 315 */ "windowdefn ::= nm AS LP window RP",
+ /* 316 */ "window ::= PARTITION BY nexprlist orderby_opt frame_opt",
+ /* 317 */ "window ::= nm PARTITION BY nexprlist orderby_opt frame_opt",
+ /* 318 */ "window ::= ORDER BY sortlist frame_opt",
+ /* 319 */ "window ::= nm ORDER BY sortlist frame_opt",
+ /* 320 */ "window ::= nm frame_opt",
+ /* 321 */ "frame_opt ::=",
+ /* 322 */ "frame_opt ::= range_or_rows frame_bound_s frame_exclude_opt",
+ /* 323 */ "frame_opt ::= range_or_rows BETWEEN frame_bound_s AND frame_bound_e frame_exclude_opt",
+ /* 324 */ "range_or_rows ::= RANGE|ROWS|GROUPS",
+ /* 325 */ "frame_bound_s ::= frame_bound",
+ /* 326 */ "frame_bound_s ::= UNBOUNDED PRECEDING",
+ /* 327 */ "frame_bound_e ::= frame_bound",
+ /* 328 */ "frame_bound_e ::= UNBOUNDED FOLLOWING",
+ /* 329 */ "frame_bound ::= expr PRECEDING|FOLLOWING",
+ /* 330 */ "frame_bound ::= CURRENT ROW",
+ /* 331 */ "frame_exclude_opt ::=",
+ /* 332 */ "frame_exclude_opt ::= EXCLUDE frame_exclude",
+ /* 333 */ "frame_exclude ::= NO OTHERS",
+ /* 334 */ "frame_exclude ::= CURRENT ROW",
+ /* 335 */ "frame_exclude ::= GROUP|TIES",
+ /* 336 */ "window_clause ::= WINDOW windowdefn_list",
+ /* 337 */ "filter_over ::= filter_clause over_clause",
+ /* 338 */ "filter_over ::= over_clause",
+ /* 339 */ "filter_over ::= filter_clause",
+ /* 340 */ "over_clause ::= OVER LP window RP",
+ /* 341 */ "over_clause ::= OVER nm",
+ /* 342 */ "filter_clause ::= FILTER LP WHERE expr RP",
+ /* 343 */ "term ::= QNUMBER",
+ /* 344 */ "input ::= cmdlist",
+ /* 345 */ "cmdlist ::= cmdlist ecmd",
+ /* 346 */ "cmdlist ::= ecmd",
+ /* 347 */ "ecmd ::= SEMI",
+ /* 348 */ "ecmd ::= cmdx SEMI",
+ /* 349 */ "ecmd ::= explain cmdx SEMI",
+ /* 350 */ "trans_opt ::=",
+ /* 351 */ "trans_opt ::= TRANSACTION",
+ /* 352 */ "trans_opt ::= TRANSACTION nm",
+ /* 353 */ "savepoint_opt ::= SAVEPOINT",
+ /* 354 */ "savepoint_opt ::=",
+ /* 355 */ "cmd ::= create_table create_table_args",
+ /* 356 */ "table_option_set ::= table_option",
+ /* 357 */ "columnlist ::= columnlist COMMA columnname carglist",
+ /* 358 */ "columnlist ::= columnname carglist",
+ /* 359 */ "nm ::= ID|INDEXED|JOIN_KW",
+ /* 360 */ "nm ::= STRING",
+ /* 361 */ "typetoken ::= typename",
+ /* 362 */ "typename ::= ID|STRING",
+ /* 363 */ "signed ::= plus_num",
+ /* 364 */ "signed ::= minus_num",
+ /* 365 */ "carglist ::= carglist ccons",
+ /* 366 */ "carglist ::=",
+ /* 367 */ "ccons ::= NULL onconf",
+ /* 368 */ "ccons ::= GENERATED ALWAYS AS generated",
+ /* 369 */ "ccons ::= AS generated",
+ /* 370 */ "conslist_opt ::= COMMA conslist",
+ /* 371 */ "conslist ::= conslist tconscomma tcons",
+ /* 372 */ "conslist ::= tcons",
+ /* 373 */ "tconscomma ::=",
+ /* 374 */ "defer_subclause_opt ::= defer_subclause",
+ /* 375 */ "resolvetype ::= raisetype",
+ /* 376 */ "selectnowith ::= oneselect",
+ /* 377 */ "oneselect ::= values",
+ /* 378 */ "sclp ::= selcollist COMMA",
+ /* 379 */ "as ::= ID|STRING",
+ /* 380 */ "indexed_opt ::= indexed_by",
+ /* 381 */ "returning ::=",
+ /* 382 */ "expr ::= term",
+ /* 383 */ "likeop ::= LIKE_KW|MATCH",
+ /* 384 */ "case_operand ::= expr",
+ /* 385 */ "exprlist ::= nexprlist",
+ /* 386 */ "nmnum ::= plus_num",
+ /* 387 */ "nmnum ::= nm",
+ /* 388 */ "nmnum ::= ON",
+ /* 389 */ "nmnum ::= DELETE",
+ /* 390 */ "nmnum ::= DEFAULT",
+ /* 391 */ "plus_num ::= INTEGER|FLOAT",
+ /* 392 */ "foreach_clause ::=",
+ /* 393 */ "foreach_clause ::= FOR EACH ROW",
+ /* 394 */ "trnm ::= nm",
+ /* 395 */ "tridxby ::=",
+ /* 396 */ "database_kw_opt ::= DATABASE",
+ /* 397 */ "database_kw_opt ::=",
+ /* 398 */ "kwcolumn_opt ::=",
+ /* 399 */ "kwcolumn_opt ::= COLUMNKW",
+ /* 400 */ "vtabarglist ::= vtabarg",
+ /* 401 */ "vtabarglist ::= vtabarglist COMMA vtabarg",
+ /* 402 */ "vtabarg ::= vtabarg vtabargtoken",
+ /* 403 */ "anylist ::=",
+ /* 404 */ "anylist ::= anylist LP anylist RP",
+ /* 405 */ "anylist ::= anylist ANY",
+ /* 406 */ "with ::=",
+ /* 407 */ "windowdefn_list ::= windowdefn",
+ /* 408 */ "window ::= frame_opt",
+};
+#endif /* NDEBUG */
+
+
+#if YYGROWABLESTACK
+/*
+** Try to increase the size of the parser stack.  Return the number
+** of errors.  Return 0 on success.
+*/
+static int yyGrowStack(yyParser *p){
+  int oldSize = 1 + (int)(p->yystackEnd - p->yystack);
+  int newSize;
+  int idx;
+  yyStackEntry *pNew;
+
+  newSize = oldSize*2 + 100;
+  idx = (int)(p->yytos - p->yystack);
+  if( p->yystack==p->yystk0 ){
+    pNew = YYREALLOC(0, newSize*sizeof(pNew[0]));
+    if( pNew==0 ) return 1;
+    memcpy(pNew, p->yystack, oldSize*sizeof(pNew[0]));
+  }else{
+    pNew = YYREALLOC(p->yystack, newSize*sizeof(pNew[0]));
+    if( pNew==0 ) return 1;
+  }
+  p->yystack = pNew;
+  p->yytos = &p->yystack[idx];
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sStack grows from %d to %d entries.\n",
+            yyTracePrompt, oldSize, newSize);
+  }
+#endif
+  p->yystackEnd = &p->yystack[newSize-1];
+  return 0;
+}
+#endif /* YYGROWABLESTACK */
+
+#if !YYGROWABLESTACK
+/* For builds that do no have a growable stack, yyGrowStack always
+** returns an error.
+*/
+# define yyGrowStack(X) 1
+#endif
+
+/* Datatype of the argument to the memory allocated passed as the
+** second argument to sqlite3ParserAlloc() below.  This can be changed by
+** putting an appropriate #define in the %include section of the input
+** grammar.
+*/
+#ifndef YYMALLOCARGTYPE
+# define YYMALLOCARGTYPE size_t
+#endif
+
+/* Initialize a new parser that has already been allocated.
+*/
+SQLITE_PRIVATE void sqlite3ParserInit(void *yypRawParser sqlite3ParserCTX_PDECL){
+  yyParser *yypParser = (yyParser*)yypRawParser;
+  sqlite3ParserCTX_STORE
+#ifdef YYTRACKMAXSTACKDEPTH
+  yypParser->yyhwm = 0;
+#endif
+  yypParser->yystack = yypParser->yystk0;
+  yypParser->yystackEnd = &yypParser->yystack[YYSTACKDEPTH-1];
+#ifndef YYNOERRORRECOVERY
+  yypParser->yyerrcnt = -1;
+#endif
+  yypParser->yytos = yypParser->yystack;
+  yypParser->yystack[0].stateno = 0;
+  yypParser->yystack[0].major = 0;
+}
+
+#ifndef sqlite3Parser_ENGINEALWAYSONSTACK
+/*
+** This function allocates a new parser.
+** The only argument is a pointer to a function which works like
+** malloc.
+**
+** Inputs:
+** A pointer to the function used to allocate memory.
+**
+** Outputs:
+** A pointer to a parser.  This pointer is used in subsequent calls
+** to sqlite3Parser and sqlite3ParserFree.
+*/
+SQLITE_PRIVATE void *sqlite3ParserAlloc(void *(*mallocProc)(YYMALLOCARGTYPE) sqlite3ParserCTX_PDECL){
+  yyParser *yypParser;
+  yypParser = (yyParser*)(*mallocProc)( (YYMALLOCARGTYPE)sizeof(yyParser) );
+  if( yypParser ){
+    sqlite3ParserCTX_STORE
+    sqlite3ParserInit(yypParser sqlite3ParserCTX_PARAM);
+  }
+  return (void*)yypParser;
+}
+#endif /* sqlite3Parser_ENGINEALWAYSONSTACK */
+
+
+/* The following function deletes the "minor type" or semantic value
+** associated with a symbol.  The symbol can be either a terminal
+** or nonterminal. "yymajor" is the symbol code, and "yypminor" is
+** a pointer to the value to be deleted.  The code used to do the
+** deletions is derived from the %destructor and/or %token_destructor
+** directives of the input grammar.
+*/
+static void yy_destructor(
+  yyParser *yypParser,    /* The parser */
+  YYCODETYPE yymajor,     /* Type code for object to destroy */
+  YYMINORTYPE *yypminor   /* The object to be destroyed */
+){
+  sqlite3ParserARG_FETCH
+  sqlite3ParserCTX_FETCH
+  switch( yymajor ){
+    /* Here is inserted the actions which take place when a
+    ** terminal or non-terminal is destroyed.  This can happen
+    ** when the symbol is popped from the stack during a
+    ** reduce or during error processing or when a parser is
+    ** being destroyed before it is finished parsing.
+    **
+    ** Note: during a reduce, the only symbols destroyed are those
+    ** which appear on the RHS of the rule, but which are *not* used
+    ** inside the C code.
+    */
+/********* Begin destructor definitions ***************************************/
+    case 206: /* select */
+    case 241: /* selectnowith */
+    case 242: /* oneselect */
+    case 254: /* values */
+    case 256: /* mvalues */
+{
+sqlite3SelectDelete(pParse->db, (yypminor->yy637));
+}
+      break;
+    case 218: /* term */
+    case 219: /* expr */
+    case 248: /* where_opt */
+    case 250: /* having_opt */
+    case 270: /* where_opt_ret */
+    case 281: /* case_operand */
+    case 283: /* case_else */
+    case 286: /* vinto */
+    case 293: /* when_clause */
+    case 298: /* key_opt */
+    case 315: /* filter_clause */
+{
+sqlite3ExprDelete(pParse->db, (yypminor->yy590));
+}
+      break;
+    case 223: /* eidlist_opt */
+    case 233: /* sortlist */
+    case 234: /* eidlist */
+    case 246: /* selcollist */
+    case 249: /* groupby_opt */
+    case 251: /* orderby_opt */
+    case 255: /* nexprlist */
+    case 257: /* sclp */
+    case 264: /* exprlist */
+    case 271: /* setlist */
+    case 280: /* paren_exprlist */
+    case 282: /* case_exprlist */
+    case 314: /* part_opt */
+{
+sqlite3ExprListDelete(pParse->db, (yypminor->yy402));
+}
+      break;
+    case 240: /* fullname */
+    case 247: /* from */
+    case 259: /* seltablist */
+    case 260: /* stl_prefix */
+    case 265: /* xfullname */
+{
+sqlite3SrcListDelete(pParse->db, (yypminor->yy563));
+}
+      break;
+    case 243: /* wqlist */
+{
+sqlite3WithDelete(pParse->db, (yypminor->yy125));
+}
+      break;
+    case 253: /* window_clause */
+    case 310: /* windowdefn_list */
+{
+sqlite3WindowListDelete(pParse->db, (yypminor->yy483));
+}
+      break;
+    case 266: /* idlist */
+    case 273: /* idlist_opt */
+{
+sqlite3IdListDelete(pParse->db, (yypminor->yy204));
+}
+      break;
+    case 276: /* filter_over */
+    case 311: /* windowdefn */
+    case 312: /* window */
+    case 313: /* frame_opt */
+    case 316: /* over_clause */
+{
+sqlite3WindowDelete(pParse->db, (yypminor->yy483));
+}
+      break;
+    case 289: /* trigger_cmd_list */
+    case 294: /* trigger_cmd */
+{
+sqlite3DeleteTriggerStep(pParse->db, (yypminor->yy319));
+}
+      break;
+    case 291: /* trigger_event */
+{
+sqlite3IdListDelete(pParse->db, (yypminor->yy28).b);
+}
+      break;
+    case 318: /* frame_bound */
+    case 319: /* frame_bound_s */
+    case 320: /* frame_bound_e */
+{
+sqlite3ExprDelete(pParse->db, (yypminor->yy205).pExpr);
+}
+      break;
+/********* End destructor definitions *****************************************/
+    default:  break;   /* If no destructor action specified: do nothing */
+  }
+}
+
+/*
+** Pop the parser's stack once.
+**
+** If there is a destructor routine associated with the token which
+** is popped from the stack, then call it.
+*/
+static void yy_pop_parser_stack(yyParser *pParser){
+  yyStackEntry *yytos;
+  assert( pParser->yytos!=0 );
+  assert( pParser->yytos > pParser->yystack );
+  yytos = pParser->yytos--;
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sPopping %s\n",
+      yyTracePrompt,
+      yyTokenName[yytos->major]);
+  }
+#endif
+  yy_destructor(pParser, yytos->major, &yytos->minor);
+}
+
+/*
+** Clear all secondary memory allocations from the parser
+*/
+SQLITE_PRIVATE void sqlite3ParserFinalize(void *p){
+  yyParser *pParser = (yyParser*)p;
+
+  /* In-lined version of calling yy_pop_parser_stack() for each
+  ** element left in the stack */
+  yyStackEntry *yytos = pParser->yytos;
+  while( yytos>pParser->yystack ){
+#ifndef NDEBUG
+    if( yyTraceFILE ){
+      fprintf(yyTraceFILE,"%sPopping %s\n",
+        yyTracePrompt,
+        yyTokenName[yytos->major]);
+    }
+#endif
+    if( yytos->major>=YY_MIN_DSTRCTR ){
+      yy_destructor(pParser, yytos->major, &yytos->minor);
+    }
+    yytos--;
+  }
+
+#if YYGROWABLESTACK
+  if( pParser->yystack!=pParser->yystk0 ) YYFREE(pParser->yystack);
+#endif
+}
+
+#ifndef sqlite3Parser_ENGINEALWAYSONSTACK
+/*
+** Deallocate and destroy a parser.  Destructors are called for
+** all stack elements before shutting the parser down.
+**
+** If the YYPARSEFREENEVERNULL macro exists (for example because it
+** is defined in a %include section of the input grammar) then it is
+** assumed that the input pointer is never NULL.
+*/
+SQLITE_PRIVATE void sqlite3ParserFree(
+  void *p,                    /* The parser to be deleted */
+  void (*freeProc)(void*)     /* Function used to reclaim memory */
+){
+#ifndef YYPARSEFREENEVERNULL
+  if( p==0 ) return;
+#endif
+  sqlite3ParserFinalize(p);
+  (*freeProc)(p);
+}
+#endif /* sqlite3Parser_ENGINEALWAYSONSTACK */
+
+/*
+** Return the peak depth of the stack for a parser.
+*/
+#ifdef YYTRACKMAXSTACKDEPTH
+SQLITE_PRIVATE int sqlite3ParserStackPeak(void *p){
+  yyParser *pParser = (yyParser*)p;
+  return pParser->yyhwm;
+}
+#endif
+
+/* This array of booleans keeps track of the parser statement
+** coverage.  The element yycoverage[X][Y] is set when the parser
+** is in state X and has a lookahead token Y.  In a well-tested
+** systems, every element of this matrix should end up being set.
+*/
+#if defined(YYCOVERAGE)
+static unsigned char yycoverage[YYNSTATE][YYNTOKEN];
+#endif
+
+/*
+** Write into out a description of every state/lookahead combination that
+**
+**   (1)  has not been used by the parser, and
+**   (2)  is not a syntax error.
+**
+** Return the number of missed state/lookahead combinations.
+*/
+#if defined(YYCOVERAGE)
+SQLITE_PRIVATE int sqlite3ParserCoverage(FILE *out){
+  int stateno, iLookAhead, i;
+  int nMissed = 0;
+  for(stateno=0; stateno<YYNSTATE; stateno++){
+    i = yy_shift_ofst[stateno];
+    for(iLookAhead=0; iLookAhead<YYNTOKEN; iLookAhead++){
+      if( yy_lookahead[i+iLookAhead]!=iLookAhead ) continue;
+      if( yycoverage[stateno][iLookAhead]==0 ) nMissed++;
+      if( out ){
+        fprintf(out,"State %d lookahead %s %s\n", stateno,
+                yyTokenName[iLookAhead],
+                yycoverage[stateno][iLookAhead] ? "ok" : "missed");
+      }
+    }
+  }
+  return nMissed;
+}
+#endif
+
+/*
+** Find the appropriate action for a parser given the terminal
+** look-ahead token iLookAhead.
+*/
+static YYACTIONTYPE yy_find_shift_action(
+  YYCODETYPE iLookAhead,    /* The look-ahead token */
+  YYACTIONTYPE stateno      /* Current state number */
+){
+  int i;
+
+  if( stateno>YY_MAX_SHIFT ) return stateno;
+  assert( stateno <= YY_SHIFT_COUNT );
+#if defined(YYCOVERAGE)
+  yycoverage[stateno][iLookAhead] = 1;
+#endif
+  do{
+    i = yy_shift_ofst[stateno];
+    assert( i>=0 );
+    assert( i<=YY_ACTTAB_COUNT );
+    assert( i+YYNTOKEN<=(int)YY_NLOOKAHEAD );
+    assert( iLookAhead!=YYNOCODE );
+    assert( iLookAhead < YYNTOKEN );
+    i += iLookAhead;
+    assert( i<(int)YY_NLOOKAHEAD );
+    if( yy_lookahead[i]!=iLookAhead ){
+#ifdef YYFALLBACK
+      YYCODETYPE iFallback;            /* Fallback token */
+      assert( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0]) );
+      iFallback = yyFallback[iLookAhead];
+      if( iFallback!=0 ){
+#ifndef NDEBUG
+        if( yyTraceFILE ){
+          fprintf(yyTraceFILE, "%sFALLBACK %s => %s\n",
+             yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[iFallback]);
+        }
+#endif
+        assert( yyFallback[iFallback]==0 ); /* Fallback loop must terminate */
+        iLookAhead = iFallback;
+        continue;
+      }
+#endif
+#ifdef YYWILDCARD
+      {
+        int j = i - iLookAhead + YYWILDCARD;
+        assert( j<(int)(sizeof(yy_lookahead)/sizeof(yy_lookahead[0])) );
+        if( yy_lookahead[j]==YYWILDCARD && iLookAhead>0 ){
+#ifndef NDEBUG
+          if( yyTraceFILE ){
+            fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
+               yyTracePrompt, yyTokenName[iLookAhead],
+               yyTokenName[YYWILDCARD]);
+          }
+#endif /* NDEBUG */
+          return yy_action[j];
+        }
+      }
+#endif /* YYWILDCARD */
+      return yy_default[stateno];
+    }else{
+      assert( i>=0 && i<(int)(sizeof(yy_action)/sizeof(yy_action[0])) );
+      return yy_action[i];
+    }
+  }while(1);
+}
+
+/*
+** Find the appropriate action for a parser given the non-terminal
+** look-ahead token iLookAhead.
+*/
+static YYACTIONTYPE yy_find_reduce_action(
+  YYACTIONTYPE stateno,     /* Current state number */
+  YYCODETYPE iLookAhead     /* The look-ahead token */
+){
+  int i;
+#ifdef YYERRORSYMBOL
+  if( stateno>YY_REDUCE_COUNT ){
+    return yy_default[stateno];
+  }
+#else
+  assert( stateno<=YY_REDUCE_COUNT );
+#endif
+  i = yy_reduce_ofst[stateno];
+  assert( iLookAhead!=YYNOCODE );
+  i += iLookAhead;
+#ifdef YYERRORSYMBOL
+  if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
+    return yy_default[stateno];
+  }
+#else
+  assert( i>=0 && i<YY_ACTTAB_COUNT );
+  assert( yy_lookahead[i]==iLookAhead );
+#endif
+  return yy_action[i];
+}
+
+/*
+** The following routine is called if the stack overflows.
+*/
+static void yyStackOverflow(yyParser *yypParser){
+   sqlite3ParserARG_FETCH
+   sqlite3ParserCTX_FETCH
+#ifndef NDEBUG
+   if( yyTraceFILE ){
+     fprintf(yyTraceFILE,"%sStack Overflow!\n",yyTracePrompt);
+   }
+#endif
+   while( yypParser->yytos>yypParser->yystack ) yy_pop_parser_stack(yypParser);
+   /* Here code is inserted which will execute if the parser
+   ** stack every overflows */
+/******** Begin %stack_overflow code ******************************************/
+
+  sqlite3OomFault(pParse->db);
+/******** End %stack_overflow code ********************************************/
+   sqlite3ParserARG_STORE /* Suppress warning about unused %extra_argument var */
+   sqlite3ParserCTX_STORE
+}
+
+/*
+** Print tracing information for a SHIFT action
+*/
+#ifndef NDEBUG
+static void yyTraceShift(yyParser *yypParser, int yyNewState, const char *zTag){
+  if( yyTraceFILE ){
+    if( yyNewState<YYNSTATE ){
+      fprintf(yyTraceFILE,"%s%s '%s', go to state %d\n",
+         yyTracePrompt, zTag, yyTokenName[yypParser->yytos->major],
+         yyNewState);
+    }else{
+      fprintf(yyTraceFILE,"%s%s '%s', pending reduce %d\n",
+         yyTracePrompt, zTag, yyTokenName[yypParser->yytos->major],
+         yyNewState - YY_MIN_REDUCE);
+    }
+  }
+}
+#else
+# define yyTraceShift(X,Y,Z)
+#endif
+
+/*
+** Perform a shift action.
+*/
+static void yy_shift(
+  yyParser *yypParser,          /* The parser to be shifted */
+  YYACTIONTYPE yyNewState,      /* The new state to shift in */
+  YYCODETYPE yyMajor,           /* The major token to shift in */
+  sqlite3ParserTOKENTYPE yyMinor        /* The minor token to shift in */
+){
+  yyStackEntry *yytos;
+  yypParser->yytos++;
+#ifdef YYTRACKMAXSTACKDEPTH
+  if( (int)(yypParser->yytos - yypParser->yystack)>yypParser->yyhwm ){
+    yypParser->yyhwm++;
+    assert( yypParser->yyhwm == (int)(yypParser->yytos - yypParser->yystack) );
+  }
+#endif
+  yytos = yypParser->yytos;
+  if( yytos>yypParser->yystackEnd ){
+    if( yyGrowStack(yypParser) ){
+      yypParser->yytos--;
+      yyStackOverflow(yypParser);
+      return;
+    }
+    yytos = yypParser->yytos;
+    assert( yytos <= yypParser->yystackEnd );
+  }
+  if( yyNewState > YY_MAX_SHIFT ){
+    yyNewState += YY_MIN_REDUCE - YY_MIN_SHIFTREDUCE;
+  }
+  yytos->stateno = yyNewState;
+  yytos->major = yyMajor;
+  yytos->minor.yy0 = yyMinor;
+  yyTraceShift(yypParser, yyNewState, "Shift");
+}
+
+/* For rule J, yyRuleInfoLhs[J] contains the symbol on the left-hand side
+** of that rule */
+static const YYCODETYPE yyRuleInfoLhs[] = {
+   191,  /* (0) explain ::= EXPLAIN */
+   191,  /* (1) explain ::= EXPLAIN QUERY PLAN */
+   190,  /* (2) cmdx ::= cmd */
+   192,  /* (3) cmd ::= BEGIN transtype trans_opt */
+   193,  /* (4) transtype ::= */
+   193,  /* (5) transtype ::= DEFERRED */
+   193,  /* (6) transtype ::= IMMEDIATE */
+   193,  /* (7) transtype ::= EXCLUSIVE */
+   192,  /* (8) cmd ::= COMMIT|END trans_opt */
+   192,  /* (9) cmd ::= ROLLBACK trans_opt */
+   192,  /* (10) cmd ::= SAVEPOINT nm */
+   192,  /* (11) cmd ::= RELEASE savepoint_opt nm */
+   192,  /* (12) cmd ::= ROLLBACK trans_opt TO savepoint_opt nm */
+   197,  /* (13) create_table ::= createkw temp TABLE ifnotexists nm dbnm */
+   199,  /* (14) createkw ::= CREATE */
+   201,  /* (15) ifnotexists ::= */
+   201,  /* (16) ifnotexists ::= IF NOT EXISTS */
+   200,  /* (17) temp ::= TEMP */
+   200,  /* (18) temp ::= */
+   198,  /* (19) create_table_args ::= LP columnlist conslist_opt RP table_option_set */
+   198,  /* (20) create_table_args ::= AS select */
+   205,  /* (21) table_option_set ::= */
+   205,  /* (22) table_option_set ::= table_option_set COMMA table_option */
+   207,  /* (23) table_option ::= WITHOUT nm */
+   207,  /* (24) table_option ::= nm */
+   208,  /* (25) columnname ::= nm typetoken */
+   210,  /* (26) typetoken ::= */
+   210,  /* (27) typetoken ::= typename LP signed RP */
+   210,  /* (28) typetoken ::= typename LP signed COMMA signed RP */
+   211,  /* (29) typename ::= typename ID|STRING */
+   215,  /* (30) scanpt ::= */
+   216,  /* (31) scantok ::= */
+   217,  /* (32) ccons ::= CONSTRAINT nm */
+   217,  /* (33) ccons ::= DEFAULT scantok term */
+   217,  /* (34) ccons ::= DEFAULT LP expr RP */
+   217,  /* (35) ccons ::= DEFAULT PLUS scantok term */
+   217,  /* (36) ccons ::= DEFAULT MINUS scantok term */
+   217,  /* (37) ccons ::= DEFAULT scantok ID|INDEXED */
+   217,  /* (38) ccons ::= NOT NULL onconf */
+   217,  /* (39) ccons ::= PRIMARY KEY sortorder onconf autoinc */
+   217,  /* (40) ccons ::= UNIQUE onconf */
+   217,  /* (41) ccons ::= CHECK LP expr RP */
+   217,  /* (42) ccons ::= REFERENCES nm eidlist_opt refargs */
+   217,  /* (43) ccons ::= defer_subclause */
+   217,  /* (44) ccons ::= COLLATE ID|STRING */
+   226,  /* (45) generated ::= LP expr RP */
+   226,  /* (46) generated ::= LP expr RP ID */
+   222,  /* (47) autoinc ::= */
+   222,  /* (48) autoinc ::= AUTOINCR */
+   224,  /* (49) refargs ::= */
+   224,  /* (50) refargs ::= refargs refarg */
+   227,  /* (51) refarg ::= MATCH nm */
+   227,  /* (52) refarg ::= ON INSERT refact */
+   227,  /* (53) refarg ::= ON DELETE refact */
+   227,  /* (54) refarg ::= ON UPDATE refact */
+   228,  /* (55) refact ::= SET NULL */
+   228,  /* (56) refact ::= SET DEFAULT */
+   228,  /* (57) refact ::= CASCADE */
+   228,  /* (58) refact ::= RESTRICT */
+   228,  /* (59) refact ::= NO ACTION */
+   225,  /* (60) defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt */
+   225,  /* (61) defer_subclause ::= DEFERRABLE init_deferred_pred_opt */
+   229,  /* (62) init_deferred_pred_opt ::= */
+   229,  /* (63) init_deferred_pred_opt ::= INITIALLY DEFERRED */
+   229,  /* (64) init_deferred_pred_opt ::= INITIALLY IMMEDIATE */
+   204,  /* (65) conslist_opt ::= */
+   231,  /* (66) tconscomma ::= COMMA */
+   232,  /* (67) tcons ::= CONSTRAINT nm */
+   232,  /* (68) tcons ::= PRIMARY KEY LP sortlist autoinc RP onconf */
+   232,  /* (69) tcons ::= UNIQUE LP sortlist RP onconf */
+   232,  /* (70) tcons ::= CHECK LP expr RP onconf */
+   232,  /* (71) tcons ::= FOREIGN KEY LP eidlist RP REFERENCES nm eidlist_opt refargs defer_subclause_opt */
+   235,  /* (72) defer_subclause_opt ::= */
+   220,  /* (73) onconf ::= */
+   220,  /* (74) onconf ::= ON CONFLICT resolvetype */
+   236,  /* (75) orconf ::= */
+   236,  /* (76) orconf ::= OR resolvetype */
+   237,  /* (77) resolvetype ::= IGNORE */
+   237,  /* (78) resolvetype ::= REPLACE */
+   192,  /* (79) cmd ::= DROP TABLE ifexists fullname */
+   239,  /* (80) ifexists ::= IF EXISTS */
+   239,  /* (81) ifexists ::= */
+   192,  /* (82) cmd ::= createkw temp VIEW ifnotexists nm dbnm eidlist_opt AS select */
+   192,  /* (83) cmd ::= DROP VIEW ifexists fullname */
+   192,  /* (84) cmd ::= select */
+   206,  /* (85) select ::= WITH wqlist selectnowith */
+   206,  /* (86) select ::= WITH RECURSIVE wqlist selectnowith */
+   206,  /* (87) select ::= selectnowith */
+   241,  /* (88) selectnowith ::= selectnowith multiselect_op oneselect */
+   244,  /* (89) multiselect_op ::= UNION */
+   244,  /* (90) multiselect_op ::= UNION ALL */
+   244,  /* (91) multiselect_op ::= EXCEPT|INTERSECT */
+   242,  /* (92) oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt */
+   242,  /* (93) oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt window_clause orderby_opt limit_opt */
+   254,  /* (94) values ::= VALUES LP nexprlist RP */
+   242,  /* (95) oneselect ::= mvalues */
+   256,  /* (96) mvalues ::= values COMMA LP nexprlist RP */
+   256,  /* (97) mvalues ::= mvalues COMMA LP nexprlist RP */
+   245,  /* (98) distinct ::= DISTINCT */
+   245,  /* (99) distinct ::= ALL */
+   245,  /* (100) distinct ::= */
+   257,  /* (101) sclp ::= */
+   246,  /* (102) selcollist ::= sclp scanpt expr scanpt as */
+   246,  /* (103) selcollist ::= sclp scanpt STAR */
+   246,  /* (104) selcollist ::= sclp scanpt nm DOT STAR */
+   258,  /* (105) as ::= AS nm */
+   258,  /* (106) as ::= */
+   247,  /* (107) from ::= */
+   247,  /* (108) from ::= FROM seltablist */
+   260,  /* (109) stl_prefix ::= seltablist joinop */
+   260,  /* (110) stl_prefix ::= */
+   259,  /* (111) seltablist ::= stl_prefix nm dbnm as on_using */
+   259,  /* (112) seltablist ::= stl_prefix nm dbnm as indexed_by on_using */
+   259,  /* (113) seltablist ::= stl_prefix nm dbnm LP exprlist RP as on_using */
+   259,  /* (114) seltablist ::= stl_prefix LP select RP as on_using */
+   259,  /* (115) seltablist ::= stl_prefix LP seltablist RP as on_using */
+   202,  /* (116) dbnm ::= */
+   202,  /* (117) dbnm ::= DOT nm */
+   240,  /* (118) fullname ::= nm */
+   240,  /* (119) fullname ::= nm DOT nm */
+   265,  /* (120) xfullname ::= nm */
+   265,  /* (121) xfullname ::= nm DOT nm */
+   265,  /* (122) xfullname ::= nm DOT nm AS nm */
+   265,  /* (123) xfullname ::= nm AS nm */
+   261,  /* (124) joinop ::= COMMA|JOIN */
+   261,  /* (125) joinop ::= JOIN_KW JOIN */
+   261,  /* (126) joinop ::= JOIN_KW nm JOIN */
+   261,  /* (127) joinop ::= JOIN_KW nm nm JOIN */
+   262,  /* (128) on_using ::= ON expr */
+   262,  /* (129) on_using ::= USING LP idlist RP */
+   262,  /* (130) on_using ::= */
+   267,  /* (131) indexed_opt ::= */
+   263,  /* (132) indexed_by ::= INDEXED BY nm */
+   263,  /* (133) indexed_by ::= NOT INDEXED */
+   251,  /* (134) orderby_opt ::= */
+   251,  /* (135) orderby_opt ::= ORDER BY sortlist */
+   233,  /* (136) sortlist ::= sortlist COMMA expr sortorder nulls */
+   233,  /* (137) sortlist ::= expr sortorder nulls */
+   221,  /* (138) sortorder ::= ASC */
+   221,  /* (139) sortorder ::= DESC */
+   221,  /* (140) sortorder ::= */
+   268,  /* (141) nulls ::= NULLS FIRST */
+   268,  /* (142) nulls ::= NULLS LAST */
+   268,  /* (143) nulls ::= */
+   249,  /* (144) groupby_opt ::= */
+   249,  /* (145) groupby_opt ::= GROUP BY nexprlist */
+   250,  /* (146) having_opt ::= */
+   250,  /* (147) having_opt ::= HAVING expr */
+   252,  /* (148) limit_opt ::= */
+   252,  /* (149) limit_opt ::= LIMIT expr */
+   252,  /* (150) limit_opt ::= LIMIT expr OFFSET expr */
+   252,  /* (151) limit_opt ::= LIMIT expr COMMA expr */
+   192,  /* (152) cmd ::= with DELETE FROM xfullname indexed_opt where_opt_ret orderby_opt limit_opt */
+   248,  /* (153) where_opt ::= */
+   248,  /* (154) where_opt ::= WHERE expr */
+   270,  /* (155) where_opt_ret ::= */
+   270,  /* (156) where_opt_ret ::= WHERE expr */
+   270,  /* (157) where_opt_ret ::= RETURNING selcollist */
+   270,  /* (158) where_opt_ret ::= WHERE expr RETURNING selcollist */
+   192,  /* (159) cmd ::= with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret orderby_opt limit_opt */
+   271,  /* (160) setlist ::= setlist COMMA nm EQ expr */
+   271,  /* (161) setlist ::= setlist COMMA LP idlist RP EQ expr */
+   271,  /* (162) setlist ::= nm EQ expr */
+   271,  /* (163) setlist ::= LP idlist RP EQ expr */
+   192,  /* (164) cmd ::= with insert_cmd INTO xfullname idlist_opt select upsert */
+   192,  /* (165) cmd ::= with insert_cmd INTO xfullname idlist_opt DEFAULT VALUES returning */
+   274,  /* (166) upsert ::= */
+   274,  /* (167) upsert ::= RETURNING selcollist */
+   274,  /* (168) upsert ::= ON CONFLICT LP sortlist RP where_opt DO UPDATE SET setlist where_opt upsert */
+   274,  /* (169) upsert ::= ON CONFLICT LP sortlist RP where_opt DO NOTHING upsert */
+   274,  /* (170) upsert ::= ON CONFLICT DO NOTHING returning */
+   274,  /* (171) upsert ::= ON CONFLICT DO UPDATE SET setlist where_opt returning */
+   275,  /* (172) returning ::= RETURNING selcollist */
+   272,  /* (173) insert_cmd ::= INSERT orconf */
+   272,  /* (174) insert_cmd ::= REPLACE */
+   273,  /* (175) idlist_opt ::= */
+   273,  /* (176) idlist_opt ::= LP idlist RP */
+   266,  /* (177) idlist ::= idlist COMMA nm */
+   266,  /* (178) idlist ::= nm */
+   219,  /* (179) expr ::= LP expr RP */
+   219,  /* (180) expr ::= ID|INDEXED|JOIN_KW */
+   219,  /* (181) expr ::= nm DOT nm */
+   219,  /* (182) expr ::= nm DOT nm DOT nm */
+   218,  /* (183) term ::= NULL|FLOAT|BLOB */
+   218,  /* (184) term ::= STRING */
+   218,  /* (185) term ::= INTEGER */
+   219,  /* (186) expr ::= VARIABLE */
+   219,  /* (187) expr ::= expr COLLATE ID|STRING */
+   219,  /* (188) expr ::= CAST LP expr AS typetoken RP */
+   219,  /* (189) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP */
+   219,  /* (190) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP */
+   219,  /* (191) expr ::= ID|INDEXED|JOIN_KW LP STAR RP */
+   219,  /* (192) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP filter_over */
+   219,  /* (193) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP filter_over */
+   219,  /* (194) expr ::= ID|INDEXED|JOIN_KW LP STAR RP filter_over */
+   218,  /* (195) term ::= CTIME_KW */
+   219,  /* (196) expr ::= LP nexprlist COMMA expr RP */
+   219,  /* (197) expr ::= expr AND expr */
+   219,  /* (198) expr ::= expr OR expr */
+   219,  /* (199) expr ::= expr LT|GT|GE|LE expr */
+   219,  /* (200) expr ::= expr EQ|NE expr */
+   219,  /* (201) expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr */
+   219,  /* (202) expr ::= expr PLUS|MINUS expr */
+   219,  /* (203) expr ::= expr STAR|SLASH|REM expr */
+   219,  /* (204) expr ::= expr CONCAT expr */
+   277,  /* (205) likeop ::= NOT LIKE_KW|MATCH */
+   219,  /* (206) expr ::= expr likeop expr */
+   219,  /* (207) expr ::= expr likeop expr ESCAPE expr */
+   219,  /* (208) expr ::= expr ISNULL|NOTNULL */
+   219,  /* (209) expr ::= expr NOT NULL */
+   219,  /* (210) expr ::= expr IS expr */
+   219,  /* (211) expr ::= expr IS NOT expr */
+   219,  /* (212) expr ::= expr IS NOT DISTINCT FROM expr */
+   219,  /* (213) expr ::= expr IS DISTINCT FROM expr */
+   219,  /* (214) expr ::= NOT expr */
+   219,  /* (215) expr ::= BITNOT expr */
+   219,  /* (216) expr ::= PLUS|MINUS expr */
+   219,  /* (217) expr ::= expr PTR expr */
+   278,  /* (218) between_op ::= BETWEEN */
+   278,  /* (219) between_op ::= NOT BETWEEN */
+   219,  /* (220) expr ::= expr between_op expr AND expr */
+   279,  /* (221) in_op ::= IN */
+   279,  /* (222) in_op ::= NOT IN */
+   219,  /* (223) expr ::= expr in_op LP exprlist RP */
+   219,  /* (224) expr ::= LP select RP */
+   219,  /* (225) expr ::= expr in_op LP select RP */
+   219,  /* (226) expr ::= expr in_op nm dbnm paren_exprlist */
+   219,  /* (227) expr ::= EXISTS LP select RP */
+   219,  /* (228) expr ::= CASE case_operand case_exprlist case_else END */
+   282,  /* (229) case_exprlist ::= case_exprlist WHEN expr THEN expr */
+   282,  /* (230) case_exprlist ::= WHEN expr THEN expr */
+   283,  /* (231) case_else ::= ELSE expr */
+   283,  /* (232) case_else ::= */
+   281,  /* (233) case_operand ::= */
+   264,  /* (234) exprlist ::= */
+   255,  /* (235) nexprlist ::= nexprlist COMMA expr */
+   255,  /* (236) nexprlist ::= expr */
+   280,  /* (237) paren_exprlist ::= */
+   280,  /* (238) paren_exprlist ::= LP exprlist RP */
+   192,  /* (239) cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP sortlist RP where_opt */
+   284,  /* (240) uniqueflag ::= UNIQUE */
+   284,  /* (241) uniqueflag ::= */
+   223,  /* (242) eidlist_opt ::= */
+   223,  /* (243) eidlist_opt ::= LP eidlist RP */
+   234,  /* (244) eidlist ::= eidlist COMMA nm collate sortorder */
+   234,  /* (245) eidlist ::= nm collate sortorder */
+   285,  /* (246) collate ::= */
+   285,  /* (247) collate ::= COLLATE ID|STRING */
+   192,  /* (248) cmd ::= DROP INDEX ifexists fullname */
+   192,  /* (249) cmd ::= VACUUM vinto */
+   192,  /* (250) cmd ::= VACUUM nm vinto */
+   286,  /* (251) vinto ::= INTO expr */
+   286,  /* (252) vinto ::= */
+   192,  /* (253) cmd ::= PRAGMA nm dbnm */
+   192,  /* (254) cmd ::= PRAGMA nm dbnm EQ nmnum */
+   192,  /* (255) cmd ::= PRAGMA nm dbnm LP nmnum RP */
+   192,  /* (256) cmd ::= PRAGMA nm dbnm EQ minus_num */
+   192,  /* (257) cmd ::= PRAGMA nm dbnm LP minus_num RP */
+   213,  /* (258) plus_num ::= PLUS INTEGER|FLOAT */
+   214,  /* (259) minus_num ::= MINUS INTEGER|FLOAT */
+   192,  /* (260) cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END */
+   288,  /* (261) trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause */
+   290,  /* (262) trigger_time ::= BEFORE|AFTER */
+   290,  /* (263) trigger_time ::= INSTEAD OF */
+   290,  /* (264) trigger_time ::= */
+   291,  /* (265) trigger_event ::= DELETE|INSERT */
+   291,  /* (266) trigger_event ::= UPDATE */
+   291,  /* (267) trigger_event ::= UPDATE OF idlist */
+   293,  /* (268) when_clause ::= */
+   293,  /* (269) when_clause ::= WHEN expr */
+   289,  /* (270) trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI */
+   289,  /* (271) trigger_cmd_list ::= trigger_cmd SEMI */
+   295,  /* (272) trnm ::= nm DOT nm */
+   296,  /* (273) tridxby ::= INDEXED BY nm */
+   296,  /* (274) tridxby ::= NOT INDEXED */
+   294,  /* (275) trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist from where_opt scanpt */
+   294,  /* (276) trigger_cmd ::= scanpt insert_cmd INTO trnm idlist_opt select upsert scanpt */
+   294,  /* (277) trigger_cmd ::= DELETE FROM trnm tridxby where_opt scanpt */
+   294,  /* (278) trigger_cmd ::= scanpt select scanpt */
+   219,  /* (279) expr ::= RAISE LP IGNORE RP */
+   219,  /* (280) expr ::= RAISE LP raisetype COMMA expr RP */
+   238,  /* (281) raisetype ::= ROLLBACK */
+   238,  /* (282) raisetype ::= ABORT */
+   238,  /* (283) raisetype ::= FAIL */
+   192,  /* (284) cmd ::= DROP TRIGGER ifexists fullname */
+   192,  /* (285) cmd ::= ATTACH database_kw_opt expr AS expr key_opt */
+   192,  /* (286) cmd ::= DETACH database_kw_opt expr */
+   298,  /* (287) key_opt ::= */
+   298,  /* (288) key_opt ::= KEY expr */
+   192,  /* (289) cmd ::= REINDEX */
+   192,  /* (290) cmd ::= REINDEX nm dbnm */
+   192,  /* (291) cmd ::= ANALYZE */
+   192,  /* (292) cmd ::= ANALYZE nm dbnm */
+   192,  /* (293) cmd ::= ALTER TABLE fullname RENAME TO nm */
+   192,  /* (294) cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt columnname carglist */
+   192,  /* (295) cmd ::= ALTER TABLE fullname DROP kwcolumn_opt nm */
+   299,  /* (296) add_column_fullname ::= fullname */
+   192,  /* (297) cmd ::= ALTER TABLE fullname RENAME kwcolumn_opt nm TO nm */
+   192,  /* (298) cmd ::= create_vtab */
+   192,  /* (299) cmd ::= create_vtab LP vtabarglist RP */
+   301,  /* (300) create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm */
+   303,  /* (301) vtabarg ::= */
+   304,  /* (302) vtabargtoken ::= ANY */
+   304,  /* (303) vtabargtoken ::= lp anylist RP */
+   305,  /* (304) lp ::= LP */
+   269,  /* (305) with ::= WITH wqlist */
+   269,  /* (306) with ::= WITH RECURSIVE wqlist */
+   308,  /* (307) wqas ::= AS */
+   308,  /* (308) wqas ::= AS MATERIALIZED */
+   308,  /* (309) wqas ::= AS NOT MATERIALIZED */
+   307,  /* (310) wqitem ::= withnm eidlist_opt wqas LP select RP */
+   309,  /* (311) withnm ::= nm */
+   243,  /* (312) wqlist ::= wqitem */
+   243,  /* (313) wqlist ::= wqlist COMMA wqitem */
+   310,  /* (314) windowdefn_list ::= windowdefn_list COMMA windowdefn */
+   311,  /* (315) windowdefn ::= nm AS LP window RP */
+   312,  /* (316) window ::= PARTITION BY nexprlist orderby_opt frame_opt */
+   312,  /* (317) window ::= nm PARTITION BY nexprlist orderby_opt frame_opt */
+   312,  /* (318) window ::= ORDER BY sortlist frame_opt */
+   312,  /* (319) window ::= nm ORDER BY sortlist frame_opt */
+   312,  /* (320) window ::= nm frame_opt */
+   313,  /* (321) frame_opt ::= */
+   313,  /* (322) frame_opt ::= range_or_rows frame_bound_s frame_exclude_opt */
+   313,  /* (323) frame_opt ::= range_or_rows BETWEEN frame_bound_s AND frame_bound_e frame_exclude_opt */
+   317,  /* (324) range_or_rows ::= RANGE|ROWS|GROUPS */
+   319,  /* (325) frame_bound_s ::= frame_bound */
+   319,  /* (326) frame_bound_s ::= UNBOUNDED PRECEDING */
+   320,  /* (327) frame_bound_e ::= frame_bound */
+   320,  /* (328) frame_bound_e ::= UNBOUNDED FOLLOWING */
+   318,  /* (329) frame_bound ::= expr PRECEDING|FOLLOWING */
+   318,  /* (330) frame_bound ::= CURRENT ROW */
+   321,  /* (331) frame_exclude_opt ::= */
+   321,  /* (332) frame_exclude_opt ::= EXCLUDE frame_exclude */
+   322,  /* (333) frame_exclude ::= NO OTHERS */
+   322,  /* (334) frame_exclude ::= CURRENT ROW */
+   322,  /* (335) frame_exclude ::= GROUP|TIES */
+   253,  /* (336) window_clause ::= WINDOW windowdefn_list */
+   276,  /* (337) filter_over ::= filter_clause over_clause */
+   276,  /* (338) filter_over ::= over_clause */
+   276,  /* (339) filter_over ::= filter_clause */
+   316,  /* (340) over_clause ::= OVER LP window RP */
+   316,  /* (341) over_clause ::= OVER nm */
+   315,  /* (342) filter_clause ::= FILTER LP WHERE expr RP */
+   218,  /* (343) term ::= QNUMBER */
+   187,  /* (344) input ::= cmdlist */
+   188,  /* (345) cmdlist ::= cmdlist ecmd */
+   188,  /* (346) cmdlist ::= ecmd */
+   189,  /* (347) ecmd ::= SEMI */
+   189,  /* (348) ecmd ::= cmdx SEMI */
+   189,  /* (349) ecmd ::= explain cmdx SEMI */
+   194,  /* (350) trans_opt ::= */
+   194,  /* (351) trans_opt ::= TRANSACTION */
+   194,  /* (352) trans_opt ::= TRANSACTION nm */
+   196,  /* (353) savepoint_opt ::= SAVEPOINT */
+   196,  /* (354) savepoint_opt ::= */
+   192,  /* (355) cmd ::= create_table create_table_args */
+   205,  /* (356) table_option_set ::= table_option */
+   203,  /* (357) columnlist ::= columnlist COMMA columnname carglist */
+   203,  /* (358) columnlist ::= columnname carglist */
+   195,  /* (359) nm ::= ID|INDEXED|JOIN_KW */
+   195,  /* (360) nm ::= STRING */
+   210,  /* (361) typetoken ::= typename */
+   211,  /* (362) typename ::= ID|STRING */
+   212,  /* (363) signed ::= plus_num */
+   212,  /* (364) signed ::= minus_num */
+   209,  /* (365) carglist ::= carglist ccons */
+   209,  /* (366) carglist ::= */
+   217,  /* (367) ccons ::= NULL onconf */
+   217,  /* (368) ccons ::= GENERATED ALWAYS AS generated */
+   217,  /* (369) ccons ::= AS generated */
+   204,  /* (370) conslist_opt ::= COMMA conslist */
+   230,  /* (371) conslist ::= conslist tconscomma tcons */
+   230,  /* (372) conslist ::= tcons */
+   231,  /* (373) tconscomma ::= */
+   235,  /* (374) defer_subclause_opt ::= defer_subclause */
+   237,  /* (375) resolvetype ::= raisetype */
+   241,  /* (376) selectnowith ::= oneselect */
+   242,  /* (377) oneselect ::= values */
+   257,  /* (378) sclp ::= selcollist COMMA */
+   258,  /* (379) as ::= ID|STRING */
+   267,  /* (380) indexed_opt ::= indexed_by */
+   275,  /* (381) returning ::= */
+   219,  /* (382) expr ::= term */
+   277,  /* (383) likeop ::= LIKE_KW|MATCH */
+   281,  /* (384) case_operand ::= expr */
+   264,  /* (385) exprlist ::= nexprlist */
+   287,  /* (386) nmnum ::= plus_num */
+   287,  /* (387) nmnum ::= nm */
+   287,  /* (388) nmnum ::= ON */
+   287,  /* (389) nmnum ::= DELETE */
+   287,  /* (390) nmnum ::= DEFAULT */
+   213,  /* (391) plus_num ::= INTEGER|FLOAT */
+   292,  /* (392) foreach_clause ::= */
+   292,  /* (393) foreach_clause ::= FOR EACH ROW */
+   295,  /* (394) trnm ::= nm */
+   296,  /* (395) tridxby ::= */
+   297,  /* (396) database_kw_opt ::= DATABASE */
+   297,  /* (397) database_kw_opt ::= */
+   300,  /* (398) kwcolumn_opt ::= */
+   300,  /* (399) kwcolumn_opt ::= COLUMNKW */
+   302,  /* (400) vtabarglist ::= vtabarg */
+   302,  /* (401) vtabarglist ::= vtabarglist COMMA vtabarg */
+   303,  /* (402) vtabarg ::= vtabarg vtabargtoken */
+   306,  /* (403) anylist ::= */
+   306,  /* (404) anylist ::= anylist LP anylist RP */
+   306,  /* (405) anylist ::= anylist ANY */
+   269,  /* (406) with ::= */
+   310,  /* (407) windowdefn_list ::= windowdefn */
+   312,  /* (408) window ::= frame_opt */
+};
+
+/* For rule J, yyRuleInfoNRhs[J] contains the negative of the number
+** of symbols on the right-hand side of that rule. */
+static const signed char yyRuleInfoNRhs[] = {
+   -1,  /* (0) explain ::= EXPLAIN */
+   -3,  /* (1) explain ::= EXPLAIN QUERY PLAN */
+   -1,  /* (2) cmdx ::= cmd */
+   -3,  /* (3) cmd ::= BEGIN transtype trans_opt */
+    0,  /* (4) transtype ::= */
+   -1,  /* (5) transtype ::= DEFERRED */
+   -1,  /* (6) transtype ::= IMMEDIATE */
+   -1,  /* (7) transtype ::= EXCLUSIVE */
+   -2,  /* (8) cmd ::= COMMIT|END trans_opt */
+   -2,  /* (9) cmd ::= ROLLBACK trans_opt */
+   -2,  /* (10) cmd ::= SAVEPOINT nm */
+   -3,  /* (11) cmd ::= RELEASE savepoint_opt nm */
+   -5,  /* (12) cmd ::= ROLLBACK trans_opt TO savepoint_opt nm */
+   -6,  /* (13) create_table ::= createkw temp TABLE ifnotexists nm dbnm */
+   -1,  /* (14) createkw ::= CREATE */
+    0,  /* (15) ifnotexists ::= */
+   -3,  /* (16) ifnotexists ::= IF NOT EXISTS */
+   -1,  /* (17) temp ::= TEMP */
+    0,  /* (18) temp ::= */
+   -5,  /* (19) create_table_args ::= LP columnlist conslist_opt RP table_option_set */
+   -2,  /* (20) create_table_args ::= AS select */
+    0,  /* (21) table_option_set ::= */
+   -3,  /* (22) table_option_set ::= table_option_set COMMA table_option */
+   -2,  /* (23) table_option ::= WITHOUT nm */
+   -1,  /* (24) table_option ::= nm */
+   -2,  /* (25) columnname ::= nm typetoken */
+    0,  /* (26) typetoken ::= */
+   -4,  /* (27) typetoken ::= typename LP signed RP */
+   -6,  /* (28) typetoken ::= typename LP signed COMMA signed RP */
+   -2,  /* (29) typename ::= typename ID|STRING */
+    0,  /* (30) scanpt ::= */
+    0,  /* (31) scantok ::= */
+   -2,  /* (32) ccons ::= CONSTRAINT nm */
+   -3,  /* (33) ccons ::= DEFAULT scantok term */
+   -4,  /* (34) ccons ::= DEFAULT LP expr RP */
+   -4,  /* (35) ccons ::= DEFAULT PLUS scantok term */
+   -4,  /* (36) ccons ::= DEFAULT MINUS scantok term */
+   -3,  /* (37) ccons ::= DEFAULT scantok ID|INDEXED */
+   -3,  /* (38) ccons ::= NOT NULL onconf */
+   -5,  /* (39) ccons ::= PRIMARY KEY sortorder onconf autoinc */
+   -2,  /* (40) ccons ::= UNIQUE onconf */
+   -4,  /* (41) ccons ::= CHECK LP expr RP */
+   -4,  /* (42) ccons ::= REFERENCES nm eidlist_opt refargs */
+   -1,  /* (43) ccons ::= defer_subclause */
+   -2,  /* (44) ccons ::= COLLATE ID|STRING */
+   -3,  /* (45) generated ::= LP expr RP */
+   -4,  /* (46) generated ::= LP expr RP ID */
+    0,  /* (47) autoinc ::= */
+   -1,  /* (48) autoinc ::= AUTOINCR */
+    0,  /* (49) refargs ::= */
+   -2,  /* (50) refargs ::= refargs refarg */
+   -2,  /* (51) refarg ::= MATCH nm */
+   -3,  /* (52) refarg ::= ON INSERT refact */
+   -3,  /* (53) refarg ::= ON DELETE refact */
+   -3,  /* (54) refarg ::= ON UPDATE refact */
+   -2,  /* (55) refact ::= SET NULL */
+   -2,  /* (56) refact ::= SET DEFAULT */
+   -1,  /* (57) refact ::= CASCADE */
+   -1,  /* (58) refact ::= RESTRICT */
+   -2,  /* (59) refact ::= NO ACTION */
+   -3,  /* (60) defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt */
+   -2,  /* (61) defer_subclause ::= DEFERRABLE init_deferred_pred_opt */
+    0,  /* (62) init_deferred_pred_opt ::= */
+   -2,  /* (63) init_deferred_pred_opt ::= INITIALLY DEFERRED */
+   -2,  /* (64) init_deferred_pred_opt ::= INITIALLY IMMEDIATE */
+    0,  /* (65) conslist_opt ::= */
+   -1,  /* (66) tconscomma ::= COMMA */
+   -2,  /* (67) tcons ::= CONSTRAINT nm */
+   -7,  /* (68) tcons ::= PRIMARY KEY LP sortlist autoinc RP onconf */
+   -5,  /* (69) tcons ::= UNIQUE LP sortlist RP onconf */
+   -5,  /* (70) tcons ::= CHECK LP expr RP onconf */
+  -10,  /* (71) tcons ::= FOREIGN KEY LP eidlist RP REFERENCES nm eidlist_opt refargs defer_subclause_opt */
+    0,  /* (72) defer_subclause_opt ::= */
+    0,  /* (73) onconf ::= */
+   -3,  /* (74) onconf ::= ON CONFLICT resolvetype */
+    0,  /* (75) orconf ::= */
+   -2,  /* (76) orconf ::= OR resolvetype */
+   -1,  /* (77) resolvetype ::= IGNORE */
+   -1,  /* (78) resolvetype ::= REPLACE */
+   -4,  /* (79) cmd ::= DROP TABLE ifexists fullname */
+   -2,  /* (80) ifexists ::= IF EXISTS */
+    0,  /* (81) ifexists ::= */
+   -9,  /* (82) cmd ::= createkw temp VIEW ifnotexists nm dbnm eidlist_opt AS select */
+   -4,  /* (83) cmd ::= DROP VIEW ifexists fullname */
+   -1,  /* (84) cmd ::= select */
+   -3,  /* (85) select ::= WITH wqlist selectnowith */
+   -4,  /* (86) select ::= WITH RECURSIVE wqlist selectnowith */
+   -1,  /* (87) select ::= selectnowith */
+   -3,  /* (88) selectnowith ::= selectnowith multiselect_op oneselect */
+   -1,  /* (89) multiselect_op ::= UNION */
+   -2,  /* (90) multiselect_op ::= UNION ALL */
+   -1,  /* (91) multiselect_op ::= EXCEPT|INTERSECT */
+   -9,  /* (92) oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt */
+  -10,  /* (93) oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt window_clause orderby_opt limit_opt */
+   -4,  /* (94) values ::= VALUES LP nexprlist RP */
+   -1,  /* (95) oneselect ::= mvalues */
+   -5,  /* (96) mvalues ::= values COMMA LP nexprlist RP */
+   -5,  /* (97) mvalues ::= mvalues COMMA LP nexprlist RP */
+   -1,  /* (98) distinct ::= DISTINCT */
+   -1,  /* (99) distinct ::= ALL */
+    0,  /* (100) distinct ::= */
+    0,  /* (101) sclp ::= */
+   -5,  /* (102) selcollist ::= sclp scanpt expr scanpt as */
+   -3,  /* (103) selcollist ::= sclp scanpt STAR */
+   -5,  /* (104) selcollist ::= sclp scanpt nm DOT STAR */
+   -2,  /* (105) as ::= AS nm */
+    0,  /* (106) as ::= */
+    0,  /* (107) from ::= */
+   -2,  /* (108) from ::= FROM seltablist */
+   -2,  /* (109) stl_prefix ::= seltablist joinop */
+    0,  /* (110) stl_prefix ::= */
+   -5,  /* (111) seltablist ::= stl_prefix nm dbnm as on_using */
+   -6,  /* (112) seltablist ::= stl_prefix nm dbnm as indexed_by on_using */
+   -8,  /* (113) seltablist ::= stl_prefix nm dbnm LP exprlist RP as on_using */
+   -6,  /* (114) seltablist ::= stl_prefix LP select RP as on_using */
+   -6,  /* (115) seltablist ::= stl_prefix LP seltablist RP as on_using */
+    0,  /* (116) dbnm ::= */
+   -2,  /* (117) dbnm ::= DOT nm */
+   -1,  /* (118) fullname ::= nm */
+   -3,  /* (119) fullname ::= nm DOT nm */
+   -1,  /* (120) xfullname ::= nm */
+   -3,  /* (121) xfullname ::= nm DOT nm */
+   -5,  /* (122) xfullname ::= nm DOT nm AS nm */
+   -3,  /* (123) xfullname ::= nm AS nm */
+   -1,  /* (124) joinop ::= COMMA|JOIN */
+   -2,  /* (125) joinop ::= JOIN_KW JOIN */
+   -3,  /* (126) joinop ::= JOIN_KW nm JOIN */
+   -4,  /* (127) joinop ::= JOIN_KW nm nm JOIN */
+   -2,  /* (128) on_using ::= ON expr */
+   -4,  /* (129) on_using ::= USING LP idlist RP */
+    0,  /* (130) on_using ::= */
+    0,  /* (131) indexed_opt ::= */
+   -3,  /* (132) indexed_by ::= INDEXED BY nm */
+   -2,  /* (133) indexed_by ::= NOT INDEXED */
+    0,  /* (134) orderby_opt ::= */
+   -3,  /* (135) orderby_opt ::= ORDER BY sortlist */
+   -5,  /* (136) sortlist ::= sortlist COMMA expr sortorder nulls */
+   -3,  /* (137) sortlist ::= expr sortorder nulls */
+   -1,  /* (138) sortorder ::= ASC */
+   -1,  /* (139) sortorder ::= DESC */
+    0,  /* (140) sortorder ::= */
+   -2,  /* (141) nulls ::= NULLS FIRST */
+   -2,  /* (142) nulls ::= NULLS LAST */
+    0,  /* (143) nulls ::= */
+    0,  /* (144) groupby_opt ::= */
+   -3,  /* (145) groupby_opt ::= GROUP BY nexprlist */
+    0,  /* (146) having_opt ::= */
+   -2,  /* (147) having_opt ::= HAVING expr */
+    0,  /* (148) limit_opt ::= */
+   -2,  /* (149) limit_opt ::= LIMIT expr */
+   -4,  /* (150) limit_opt ::= LIMIT expr OFFSET expr */
+   -4,  /* (151) limit_opt ::= LIMIT expr COMMA expr */
+   -8,  /* (152) cmd ::= with DELETE FROM xfullname indexed_opt where_opt_ret orderby_opt limit_opt */
+    0,  /* (153) where_opt ::= */
+   -2,  /* (154) where_opt ::= WHERE expr */
+    0,  /* (155) where_opt_ret ::= */
+   -2,  /* (156) where_opt_ret ::= WHERE expr */
+   -2,  /* (157) where_opt_ret ::= RETURNING selcollist */
+   -4,  /* (158) where_opt_ret ::= WHERE expr RETURNING selcollist */
+  -11,  /* (159) cmd ::= with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret orderby_opt limit_opt */
+   -5,  /* (160) setlist ::= setlist COMMA nm EQ expr */
+   -7,  /* (161) setlist ::= setlist COMMA LP idlist RP EQ expr */
+   -3,  /* (162) setlist ::= nm EQ expr */
+   -5,  /* (163) setlist ::= LP idlist RP EQ expr */
+   -7,  /* (164) cmd ::= with insert_cmd INTO xfullname idlist_opt select upsert */
+   -8,  /* (165) cmd ::= with insert_cmd INTO xfullname idlist_opt DEFAULT VALUES returning */
+    0,  /* (166) upsert ::= */
+   -2,  /* (167) upsert ::= RETURNING selcollist */
+  -12,  /* (168) upsert ::= ON CONFLICT LP sortlist RP where_opt DO UPDATE SET setlist where_opt upsert */
+   -9,  /* (169) upsert ::= ON CONFLICT LP sortlist RP where_opt DO NOTHING upsert */
+   -5,  /* (170) upsert ::= ON CONFLICT DO NOTHING returning */
+   -8,  /* (171) upsert ::= ON CONFLICT DO UPDATE SET setlist where_opt returning */
+   -2,  /* (172) returning ::= RETURNING selcollist */
+   -2,  /* (173) insert_cmd ::= INSERT orconf */
+   -1,  /* (174) insert_cmd ::= REPLACE */
+    0,  /* (175) idlist_opt ::= */
+   -3,  /* (176) idlist_opt ::= LP idlist RP */
+   -3,  /* (177) idlist ::= idlist COMMA nm */
+   -1,  /* (178) idlist ::= nm */
+   -3,  /* (179) expr ::= LP expr RP */
+   -1,  /* (180) expr ::= ID|INDEXED|JOIN_KW */
+   -3,  /* (181) expr ::= nm DOT nm */
+   -5,  /* (182) expr ::= nm DOT nm DOT nm */
+   -1,  /* (183) term ::= NULL|FLOAT|BLOB */
+   -1,  /* (184) term ::= STRING */
+   -1,  /* (185) term ::= INTEGER */
+   -1,  /* (186) expr ::= VARIABLE */
+   -3,  /* (187) expr ::= expr COLLATE ID|STRING */
+   -6,  /* (188) expr ::= CAST LP expr AS typetoken RP */
+   -5,  /* (189) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP */
+   -8,  /* (190) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP */
+   -4,  /* (191) expr ::= ID|INDEXED|JOIN_KW LP STAR RP */
+   -6,  /* (192) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP filter_over */
+   -9,  /* (193) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP filter_over */
+   -5,  /* (194) expr ::= ID|INDEXED|JOIN_KW LP STAR RP filter_over */
+   -1,  /* (195) term ::= CTIME_KW */
+   -5,  /* (196) expr ::= LP nexprlist COMMA expr RP */
+   -3,  /* (197) expr ::= expr AND expr */
+   -3,  /* (198) expr ::= expr OR expr */
+   -3,  /* (199) expr ::= expr LT|GT|GE|LE expr */
+   -3,  /* (200) expr ::= expr EQ|NE expr */
+   -3,  /* (201) expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr */
+   -3,  /* (202) expr ::= expr PLUS|MINUS expr */
+   -3,  /* (203) expr ::= expr STAR|SLASH|REM expr */
+   -3,  /* (204) expr ::= expr CONCAT expr */
+   -2,  /* (205) likeop ::= NOT LIKE_KW|MATCH */
+   -3,  /* (206) expr ::= expr likeop expr */
+   -5,  /* (207) expr ::= expr likeop expr ESCAPE expr */
+   -2,  /* (208) expr ::= expr ISNULL|NOTNULL */
+   -3,  /* (209) expr ::= expr NOT NULL */
+   -3,  /* (210) expr ::= expr IS expr */
+   -4,  /* (211) expr ::= expr IS NOT expr */
+   -6,  /* (212) expr ::= expr IS NOT DISTINCT FROM expr */
+   -5,  /* (213) expr ::= expr IS DISTINCT FROM expr */
+   -2,  /* (214) expr ::= NOT expr */
+   -2,  /* (215) expr ::= BITNOT expr */
+   -2,  /* (216) expr ::= PLUS|MINUS expr */
+   -3,  /* (217) expr ::= expr PTR expr */
+   -1,  /* (218) between_op ::= BETWEEN */
+   -2,  /* (219) between_op ::= NOT BETWEEN */
+   -5,  /* (220) expr ::= expr between_op expr AND expr */
+   -1,  /* (221) in_op ::= IN */
+   -2,  /* (222) in_op ::= NOT IN */
+   -5,  /* (223) expr ::= expr in_op LP exprlist RP */
+   -3,  /* (224) expr ::= LP select RP */
+   -5,  /* (225) expr ::= expr in_op LP select RP */
+   -5,  /* (226) expr ::= expr in_op nm dbnm paren_exprlist */
+   -4,  /* (227) expr ::= EXISTS LP select RP */
+   -5,  /* (228) expr ::= CASE case_operand case_exprlist case_else END */
+   -5,  /* (229) case_exprlist ::= case_exprlist WHEN expr THEN expr */
+   -4,  /* (230) case_exprlist ::= WHEN expr THEN expr */
+   -2,  /* (231) case_else ::= ELSE expr */
+    0,  /* (232) case_else ::= */
+    0,  /* (233) case_operand ::= */
+    0,  /* (234) exprlist ::= */
+   -3,  /* (235) nexprlist ::= nexprlist COMMA expr */
+   -1,  /* (236) nexprlist ::= expr */
+    0,  /* (237) paren_exprlist ::= */
+   -3,  /* (238) paren_exprlist ::= LP exprlist RP */
+  -12,  /* (239) cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP sortlist RP where_opt */
+   -1,  /* (240) uniqueflag ::= UNIQUE */
+    0,  /* (241) uniqueflag ::= */
+    0,  /* (242) eidlist_opt ::= */
+   -3,  /* (243) eidlist_opt ::= LP eidlist RP */
+   -5,  /* (244) eidlist ::= eidlist COMMA nm collate sortorder */
+   -3,  /* (245) eidlist ::= nm collate sortorder */
+    0,  /* (246) collate ::= */
+   -2,  /* (247) collate ::= COLLATE ID|STRING */
+   -4,  /* (248) cmd ::= DROP INDEX ifexists fullname */
+   -2,  /* (249) cmd ::= VACUUM vinto */
+   -3,  /* (250) cmd ::= VACUUM nm vinto */
+   -2,  /* (251) vinto ::= INTO expr */
+    0,  /* (252) vinto ::= */
+   -3,  /* (253) cmd ::= PRAGMA nm dbnm */
+   -5,  /* (254) cmd ::= PRAGMA nm dbnm EQ nmnum */
+   -6,  /* (255) cmd ::= PRAGMA nm dbnm LP nmnum RP */
+   -5,  /* (256) cmd ::= PRAGMA nm dbnm EQ minus_num */
+   -6,  /* (257) cmd ::= PRAGMA nm dbnm LP minus_num RP */
+   -2,  /* (258) plus_num ::= PLUS INTEGER|FLOAT */
+   -2,  /* (259) minus_num ::= MINUS INTEGER|FLOAT */
+   -5,  /* (260) cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END */
+  -11,  /* (261) trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause */
+   -1,  /* (262) trigger_time ::= BEFORE|AFTER */
+   -2,  /* (263) trigger_time ::= INSTEAD OF */
+    0,  /* (264) trigger_time ::= */
+   -1,  /* (265) trigger_event ::= DELETE|INSERT */
+   -1,  /* (266) trigger_event ::= UPDATE */
+   -3,  /* (267) trigger_event ::= UPDATE OF idlist */
+    0,  /* (268) when_clause ::= */
+   -2,  /* (269) when_clause ::= WHEN expr */
+   -3,  /* (270) trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI */
+   -2,  /* (271) trigger_cmd_list ::= trigger_cmd SEMI */
+   -3,  /* (272) trnm ::= nm DOT nm */
+   -3,  /* (273) tridxby ::= INDEXED BY nm */
+   -2,  /* (274) tridxby ::= NOT INDEXED */
+   -9,  /* (275) trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist from where_opt scanpt */
+   -8,  /* (276) trigger_cmd ::= scanpt insert_cmd INTO trnm idlist_opt select upsert scanpt */
+   -6,  /* (277) trigger_cmd ::= DELETE FROM trnm tridxby where_opt scanpt */
+   -3,  /* (278) trigger_cmd ::= scanpt select scanpt */
+   -4,  /* (279) expr ::= RAISE LP IGNORE RP */
+   -6,  /* (280) expr ::= RAISE LP raisetype COMMA expr RP */
+   -1,  /* (281) raisetype ::= ROLLBACK */
+   -1,  /* (282) raisetype ::= ABORT */
+   -1,  /* (283) raisetype ::= FAIL */
+   -4,  /* (284) cmd ::= DROP TRIGGER ifexists fullname */
+   -6,  /* (285) cmd ::= ATTACH database_kw_opt expr AS expr key_opt */
+   -3,  /* (286) cmd ::= DETACH database_kw_opt expr */
+    0,  /* (287) key_opt ::= */
+   -2,  /* (288) key_opt ::= KEY expr */
+   -1,  /* (289) cmd ::= REINDEX */
+   -3,  /* (290) cmd ::= REINDEX nm dbnm */
+   -1,  /* (291) cmd ::= ANALYZE */
+   -3,  /* (292) cmd ::= ANALYZE nm dbnm */
+   -6,  /* (293) cmd ::= ALTER TABLE fullname RENAME TO nm */
+   -7,  /* (294) cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt columnname carglist */
+   -6,  /* (295) cmd ::= ALTER TABLE fullname DROP kwcolumn_opt nm */
+   -1,  /* (296) add_column_fullname ::= fullname */
+   -8,  /* (297) cmd ::= ALTER TABLE fullname RENAME kwcolumn_opt nm TO nm */
+   -1,  /* (298) cmd ::= create_vtab */
+   -4,  /* (299) cmd ::= create_vtab LP vtabarglist RP */
+   -8,  /* (300) create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm */
+    0,  /* (301) vtabarg ::= */
+   -1,  /* (302) vtabargtoken ::= ANY */
+   -3,  /* (303) vtabargtoken ::= lp anylist RP */
+   -1,  /* (304) lp ::= LP */
+   -2,  /* (305) with ::= WITH wqlist */
+   -3,  /* (306) with ::= WITH RECURSIVE wqlist */
+   -1,  /* (307) wqas ::= AS */
+   -2,  /* (308) wqas ::= AS MATERIALIZED */
+   -3,  /* (309) wqas ::= AS NOT MATERIALIZED */
+   -6,  /* (310) wqitem ::= withnm eidlist_opt wqas LP select RP */
+   -1,  /* (311) withnm ::= nm */
+   -1,  /* (312) wqlist ::= wqitem */
+   -3,  /* (313) wqlist ::= wqlist COMMA wqitem */
+   -3,  /* (314) windowdefn_list ::= windowdefn_list COMMA windowdefn */
+   -5,  /* (315) windowdefn ::= nm AS LP window RP */
+   -5,  /* (316) window ::= PARTITION BY nexprlist orderby_opt frame_opt */
+   -6,  /* (317) window ::= nm PARTITION BY nexprlist orderby_opt frame_opt */
+   -4,  /* (318) window ::= ORDER BY sortlist frame_opt */
+   -5,  /* (319) window ::= nm ORDER BY sortlist frame_opt */
+   -2,  /* (320) window ::= nm frame_opt */
+    0,  /* (321) frame_opt ::= */
+   -3,  /* (322) frame_opt ::= range_or_rows frame_bound_s frame_exclude_opt */
+   -6,  /* (323) frame_opt ::= range_or_rows BETWEEN frame_bound_s AND frame_bound_e frame_exclude_opt */
+   -1,  /* (324) range_or_rows ::= RANGE|ROWS|GROUPS */
+   -1,  /* (325) frame_bound_s ::= frame_bound */
+   -2,  /* (326) frame_bound_s ::= UNBOUNDED PRECEDING */
+   -1,  /* (327) frame_bound_e ::= frame_bound */
+   -2,  /* (328) frame_bound_e ::= UNBOUNDED FOLLOWING */
+   -2,  /* (329) frame_bound ::= expr PRECEDING|FOLLOWING */
+   -2,  /* (330) frame_bound ::= CURRENT ROW */
+    0,  /* (331) frame_exclude_opt ::= */
+   -2,  /* (332) frame_exclude_opt ::= EXCLUDE frame_exclude */
+   -2,  /* (333) frame_exclude ::= NO OTHERS */
+   -2,  /* (334) frame_exclude ::= CURRENT ROW */
+   -1,  /* (335) frame_exclude ::= GROUP|TIES */
+   -2,  /* (336) window_clause ::= WINDOW windowdefn_list */
+   -2,  /* (337) filter_over ::= filter_clause over_clause */
+   -1,  /* (338) filter_over ::= over_clause */
+   -1,  /* (339) filter_over ::= filter_clause */
+   -4,  /* (340) over_clause ::= OVER LP window RP */
+   -2,  /* (341) over_clause ::= OVER nm */
+   -5,  /* (342) filter_clause ::= FILTER LP WHERE expr RP */
+   -1,  /* (343) term ::= QNUMBER */
+   -1,  /* (344) input ::= cmdlist */
+   -2,  /* (345) cmdlist ::= cmdlist ecmd */
+   -1,  /* (346) cmdlist ::= ecmd */
+   -1,  /* (347) ecmd ::= SEMI */
+   -2,  /* (348) ecmd ::= cmdx SEMI */
+   -3,  /* (349) ecmd ::= explain cmdx SEMI */
+    0,  /* (350) trans_opt ::= */
+   -1,  /* (351) trans_opt ::= TRANSACTION */
+   -2,  /* (352) trans_opt ::= TRANSACTION nm */
+   -1,  /* (353) savepoint_opt ::= SAVEPOINT */
+    0,  /* (354) savepoint_opt ::= */
+   -2,  /* (355) cmd ::= create_table create_table_args */
+   -1,  /* (356) table_option_set ::= table_option */
+   -4,  /* (357) columnlist ::= columnlist COMMA columnname carglist */
+   -2,  /* (358) columnlist ::= columnname carglist */
+   -1,  /* (359) nm ::= ID|INDEXED|JOIN_KW */
+   -1,  /* (360) nm ::= STRING */
+   -1,  /* (361) typetoken ::= typename */
+   -1,  /* (362) typename ::= ID|STRING */
+   -1,  /* (363) signed ::= plus_num */
+   -1,  /* (364) signed ::= minus_num */
+   -2,  /* (365) carglist ::= carglist ccons */
+    0,  /* (366) carglist ::= */
+   -2,  /* (367) ccons ::= NULL onconf */
+   -4,  /* (368) ccons ::= GENERATED ALWAYS AS generated */
+   -2,  /* (369) ccons ::= AS generated */
+   -2,  /* (370) conslist_opt ::= COMMA conslist */
+   -3,  /* (371) conslist ::= conslist tconscomma tcons */
+   -1,  /* (372) conslist ::= tcons */
+    0,  /* (373) tconscomma ::= */
+   -1,  /* (374) defer_subclause_opt ::= defer_subclause */
+   -1,  /* (375) resolvetype ::= raisetype */
+   -1,  /* (376) selectnowith ::= oneselect */
+   -1,  /* (377) oneselect ::= values */
+   -2,  /* (378) sclp ::= selcollist COMMA */
+   -1,  /* (379) as ::= ID|STRING */
+   -1,  /* (380) indexed_opt ::= indexed_by */
+    0,  /* (381) returning ::= */
+   -1,  /* (382) expr ::= term */
+   -1,  /* (383) likeop ::= LIKE_KW|MATCH */
+   -1,  /* (384) case_operand ::= expr */
+   -1,  /* (385) exprlist ::= nexprlist */
+   -1,  /* (386) nmnum ::= plus_num */
+   -1,  /* (387) nmnum ::= nm */
+   -1,  /* (388) nmnum ::= ON */
+   -1,  /* (389) nmnum ::= DELETE */
+   -1,  /* (390) nmnum ::= DEFAULT */
+   -1,  /* (391) plus_num ::= INTEGER|FLOAT */
+    0,  /* (392) foreach_clause ::= */
+   -3,  /* (393) foreach_clause ::= FOR EACH ROW */
+   -1,  /* (394) trnm ::= nm */
+    0,  /* (395) tridxby ::= */
+   -1,  /* (396) database_kw_opt ::= DATABASE */
+    0,  /* (397) database_kw_opt ::= */
+    0,  /* (398) kwcolumn_opt ::= */
+   -1,  /* (399) kwcolumn_opt ::= COLUMNKW */
+   -1,  /* (400) vtabarglist ::= vtabarg */
+   -3,  /* (401) vtabarglist ::= vtabarglist COMMA vtabarg */
+   -2,  /* (402) vtabarg ::= vtabarg vtabargtoken */
+    0,  /* (403) anylist ::= */
+   -4,  /* (404) anylist ::= anylist LP anylist RP */
+   -2,  /* (405) anylist ::= anylist ANY */
+    0,  /* (406) with ::= */
+   -1,  /* (407) windowdefn_list ::= windowdefn */
+   -1,  /* (408) window ::= frame_opt */
+};
+
+static void yy_accept(yyParser*);  /* Forward Declaration */
+
+/*
+** Perform a reduce action and the shift that must immediately
+** follow the reduce.
+**
+** The yyLookahead and yyLookaheadToken parameters provide reduce actions
+** access to the lookahead token (if any).  The yyLookahead will be YYNOCODE
+** if the lookahead token has already been consumed.  As this procedure is
+** only called from one place, optimizing compilers will in-line it, which
+** means that the extra parameters have no performance impact.
+*/
+static YYACTIONTYPE yy_reduce(
+  yyParser *yypParser,         /* The parser */
+  unsigned int yyruleno,       /* Number of the rule by which to reduce */
+  int yyLookahead,             /* Lookahead token, or YYNOCODE if none */
+  sqlite3ParserTOKENTYPE yyLookaheadToken  /* Value of the lookahead token */
+  sqlite3ParserCTX_PDECL                   /* %extra_context */
+){
+  int yygoto;                     /* The next state */
+  YYACTIONTYPE yyact;             /* The next action */
+  yyStackEntry *yymsp;            /* The top of the parser's stack */
+  int yysize;                     /* Amount to pop the stack */
+  sqlite3ParserARG_FETCH
+  (void)yyLookahead;
+  (void)yyLookaheadToken;
+  yymsp = yypParser->yytos;
+
+  switch( yyruleno ){
+  /* Beginning here are the reduction cases.  A typical example
+  ** follows:
+  **   case 0:
+  **  #line <lineno> <grammarfile>
+  **     { ... }           // User supplied code
+  **  #line <lineno> <thisfile>
+  **     break;
+  */
+/********** Begin reduce actions **********************************************/
+        YYMINORTYPE yylhsminor;
+      case 0: /* explain ::= EXPLAIN */
+{ if( pParse->pReprepare==0 ) pParse->explain = 1; }
+        break;
+      case 1: /* explain ::= EXPLAIN QUERY PLAN */
+{ if( pParse->pReprepare==0 ) pParse->explain = 2; }
+        break;
+      case 2: /* cmdx ::= cmd */
+{ sqlite3FinishCoding(pParse); }
+        break;
+      case 3: /* cmd ::= BEGIN transtype trans_opt */
+{sqlite3BeginTransaction(pParse, yymsp[-1].minor.yy502);}
+        break;
+      case 4: /* transtype ::= */
+{yymsp[1].minor.yy502 = TK_DEFERRED;}
+        break;
+      case 5: /* transtype ::= DEFERRED */
+      case 6: /* transtype ::= IMMEDIATE */ yytestcase(yyruleno==6);
+      case 7: /* transtype ::= EXCLUSIVE */ yytestcase(yyruleno==7);
+      case 324: /* range_or_rows ::= RANGE|ROWS|GROUPS */ yytestcase(yyruleno==324);
+{yymsp[0].minor.yy502 = yymsp[0].major; /*A-overwrites-X*/}
+        break;
+      case 8: /* cmd ::= COMMIT|END trans_opt */
+      case 9: /* cmd ::= ROLLBACK trans_opt */ yytestcase(yyruleno==9);
+{sqlite3EndTransaction(pParse,yymsp[-1].major);}
+        break;
+      case 10: /* cmd ::= SAVEPOINT nm */
+{
+  sqlite3Savepoint(pParse, SAVEPOINT_BEGIN, &yymsp[0].minor.yy0);
+}
+        break;
+      case 11: /* cmd ::= RELEASE savepoint_opt nm */
+{
+  sqlite3Savepoint(pParse, SAVEPOINT_RELEASE, &yymsp[0].minor.yy0);
+}
+        break;
+      case 12: /* cmd ::= ROLLBACK trans_opt TO savepoint_opt nm */
+{
+  sqlite3Savepoint(pParse, SAVEPOINT_ROLLBACK, &yymsp[0].minor.yy0);
+}
+        break;
+      case 13: /* create_table ::= createkw temp TABLE ifnotexists nm dbnm */
+{
+   sqlite3StartTable(pParse,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy0,yymsp[-4].minor.yy502,0,0,yymsp[-2].minor.yy502);
+}
+        break;
+      case 14: /* createkw ::= CREATE */
+{disableLookaside(pParse);}
+        break;
+      case 15: /* ifnotexists ::= */
+      case 18: /* temp ::= */ yytestcase(yyruleno==18);
+      case 47: /* autoinc ::= */ yytestcase(yyruleno==47);
+      case 62: /* init_deferred_pred_opt ::= */ yytestcase(yyruleno==62);
+      case 72: /* defer_subclause_opt ::= */ yytestcase(yyruleno==72);
+      case 81: /* ifexists ::= */ yytestcase(yyruleno==81);
+      case 100: /* distinct ::= */ yytestcase(yyruleno==100);
+      case 246: /* collate ::= */ yytestcase(yyruleno==246);
+{yymsp[1].minor.yy502 = 0;}
+        break;
+      case 16: /* ifnotexists ::= IF NOT EXISTS */
+{yymsp[-2].minor.yy502 = 1;}
+        break;
+      case 17: /* temp ::= TEMP */
+{yymsp[0].minor.yy502 = pParse->db->init.busy==0;}
+        break;
+      case 19: /* create_table_args ::= LP columnlist conslist_opt RP table_option_set */
+{
+  sqlite3EndTable(pParse,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0,yymsp[0].minor.yy9,0);
+}
+        break;
+      case 20: /* create_table_args ::= AS select */
+{
+  sqlite3EndTable(pParse,0,0,0,yymsp[0].minor.yy637);
+  sqlite3SelectDelete(pParse->db, yymsp[0].minor.yy637);
+}
+        break;
+      case 21: /* table_option_set ::= */
+{yymsp[1].minor.yy9 = 0;}
+        break;
+      case 22: /* table_option_set ::= table_option_set COMMA table_option */
+{yylhsminor.yy9 = yymsp[-2].minor.yy9|yymsp[0].minor.yy9;}
+  yymsp[-2].minor.yy9 = yylhsminor.yy9;
+        break;
+      case 23: /* table_option ::= WITHOUT nm */
+{
+  if( yymsp[0].minor.yy0.n==5 && sqlite3_strnicmp(yymsp[0].minor.yy0.z,"rowid",5)==0 ){
+    yymsp[-1].minor.yy9 = TF_WithoutRowid | TF_NoVisibleRowid;
+  }else{
+    yymsp[-1].minor.yy9 = 0;
+    sqlite3ErrorMsg(pParse, "unknown table option: %.*s", yymsp[0].minor.yy0.n, yymsp[0].minor.yy0.z);
+  }
+}
+        break;
+      case 24: /* table_option ::= nm */
+{
+  if( yymsp[0].minor.yy0.n==6 && sqlite3_strnicmp(yymsp[0].minor.yy0.z,"strict",6)==0 ){
+    yylhsminor.yy9 = TF_Strict;
+  }else{
+    yylhsminor.yy9 = 0;
+    sqlite3ErrorMsg(pParse, "unknown table option: %.*s", yymsp[0].minor.yy0.n, yymsp[0].minor.yy0.z);
+  }
+}
+  yymsp[0].minor.yy9 = yylhsminor.yy9;
+        break;
+      case 25: /* columnname ::= nm typetoken */
+{sqlite3AddColumn(pParse,yymsp[-1].minor.yy0,yymsp[0].minor.yy0);}
+        break;
+      case 26: /* typetoken ::= */
+      case 65: /* conslist_opt ::= */ yytestcase(yyruleno==65);
+      case 106: /* as ::= */ yytestcase(yyruleno==106);
+{yymsp[1].minor.yy0.n = 0; yymsp[1].minor.yy0.z = 0;}
+        break;
+      case 27: /* typetoken ::= typename LP signed RP */
+{
+  yymsp[-3].minor.yy0.n = (int)(&yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n] - yymsp[-3].minor.yy0.z);
+}
+        break;
+      case 28: /* typetoken ::= typename LP signed COMMA signed RP */
+{
+  yymsp[-5].minor.yy0.n = (int)(&yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n] - yymsp[-5].minor.yy0.z);
+}
+        break;
+      case 29: /* typename ::= typename ID|STRING */
+{yymsp[-1].minor.yy0.n=yymsp[0].minor.yy0.n+(int)(yymsp[0].minor.yy0.z-yymsp[-1].minor.yy0.z);}
+        break;
+      case 30: /* scanpt ::= */
+{
+  assert( yyLookahead!=YYNOCODE );
+  yymsp[1].minor.yy342 = yyLookaheadToken.z;
+}
+        break;
+      case 31: /* scantok ::= */
+{
+  assert( yyLookahead!=YYNOCODE );
+  yymsp[1].minor.yy0 = yyLookaheadToken;
+}
+        break;
+      case 32: /* ccons ::= CONSTRAINT nm */
+      case 67: /* tcons ::= CONSTRAINT nm */ yytestcase(yyruleno==67);
+{pParse->constraintName = yymsp[0].minor.yy0;}
+        break;
+      case 33: /* ccons ::= DEFAULT scantok term */
+{sqlite3AddDefaultValue(pParse,yymsp[0].minor.yy590,yymsp[-1].minor.yy0.z,&yymsp[-1].minor.yy0.z[yymsp[-1].minor.yy0.n]);}
+        break;
+      case 34: /* ccons ::= DEFAULT LP expr RP */
+{sqlite3AddDefaultValue(pParse,yymsp[-1].minor.yy590,yymsp[-2].minor.yy0.z+1,yymsp[0].minor.yy0.z);}
+        break;
+      case 35: /* ccons ::= DEFAULT PLUS scantok term */
+{sqlite3AddDefaultValue(pParse,yymsp[0].minor.yy590,yymsp[-2].minor.yy0.z,&yymsp[-1].minor.yy0.z[yymsp[-1].minor.yy0.n]);}
+        break;
+      case 36: /* ccons ::= DEFAULT MINUS scantok term */
+{
+  Expr *p = sqlite3PExpr(pParse, TK_UMINUS, yymsp[0].minor.yy590, 0);
+  sqlite3AddDefaultValue(pParse,p,yymsp[-2].minor.yy0.z,&yymsp[-1].minor.yy0.z[yymsp[-1].minor.yy0.n]);
+}
+        break;
+      case 37: /* ccons ::= DEFAULT scantok ID|INDEXED */
+{
+  Expr *p = tokenExpr(pParse, TK_STRING, yymsp[0].minor.yy0);
+  if( p ){
+    sqlite3ExprIdToTrueFalse(p);
+    testcase( p->op==TK_TRUEFALSE && sqlite3ExprTruthValue(p) );
+  }
+    sqlite3AddDefaultValue(pParse,p,yymsp[0].minor.yy0.z,yymsp[0].minor.yy0.z+yymsp[0].minor.yy0.n);
+}
+        break;
+      case 38: /* ccons ::= NOT NULL onconf */
+{sqlite3AddNotNull(pParse, yymsp[0].minor.yy502);}
+        break;
+      case 39: /* ccons ::= PRIMARY KEY sortorder onconf autoinc */
+{sqlite3AddPrimaryKey(pParse,0,yymsp[-1].minor.yy502,yymsp[0].minor.yy502,yymsp[-2].minor.yy502);}
+        break;
+      case 40: /* ccons ::= UNIQUE onconf */
+{sqlite3CreateIndex(pParse,0,0,0,0,yymsp[0].minor.yy502,0,0,0,0,
+                                   SQLITE_IDXTYPE_UNIQUE);}
+        break;
+      case 41: /* ccons ::= CHECK LP expr RP */
+{sqlite3AddCheckConstraint(pParse,yymsp[-1].minor.yy590,yymsp[-2].minor.yy0.z,yymsp[0].minor.yy0.z);}
+        break;
+      case 42: /* ccons ::= REFERENCES nm eidlist_opt refargs */
+{sqlite3CreateForeignKey(pParse,0,&yymsp[-2].minor.yy0,yymsp[-1].minor.yy402,yymsp[0].minor.yy502);}
+        break;
+      case 43: /* ccons ::= defer_subclause */
+{sqlite3DeferForeignKey(pParse,yymsp[0].minor.yy502);}
+        break;
+      case 44: /* ccons ::= COLLATE ID|STRING */
+{sqlite3AddCollateType(pParse, &yymsp[0].minor.yy0);}
+        break;
+      case 45: /* generated ::= LP expr RP */
+{sqlite3AddGenerated(pParse,yymsp[-1].minor.yy590,0);}
+        break;
+      case 46: /* generated ::= LP expr RP ID */
+{sqlite3AddGenerated(pParse,yymsp[-2].minor.yy590,&yymsp[0].minor.yy0);}
+        break;
+      case 48: /* autoinc ::= AUTOINCR */
+{yymsp[0].minor.yy502 = 1;}
+        break;
+      case 49: /* refargs ::= */
+{ yymsp[1].minor.yy502 = OE_None*0x0101; /* EV: R-19803-45884 */}
+        break;
+      case 50: /* refargs ::= refargs refarg */
+{ yymsp[-1].minor.yy502 = (yymsp[-1].minor.yy502 & ~yymsp[0].minor.yy481.mask) | yymsp[0].minor.yy481.value; }
+        break;
+      case 51: /* refarg ::= MATCH nm */
+{ yymsp[-1].minor.yy481.value = 0;     yymsp[-1].minor.yy481.mask = 0x000000; }
+        break;
+      case 52: /* refarg ::= ON INSERT refact */
+{ yymsp[-2].minor.yy481.value = 0;     yymsp[-2].minor.yy481.mask = 0x000000; }
+        break;
+      case 53: /* refarg ::= ON DELETE refact */
+{ yymsp[-2].minor.yy481.value = yymsp[0].minor.yy502;     yymsp[-2].minor.yy481.mask = 0x0000ff; }
+        break;
+      case 54: /* refarg ::= ON UPDATE refact */
+{ yymsp[-2].minor.yy481.value = yymsp[0].minor.yy502<<8;  yymsp[-2].minor.yy481.mask = 0x00ff00; }
+        break;
+      case 55: /* refact ::= SET NULL */
+{ yymsp[-1].minor.yy502 = OE_SetNull;  /* EV: R-33326-45252 */}
+        break;
+      case 56: /* refact ::= SET DEFAULT */
+{ yymsp[-1].minor.yy502 = OE_SetDflt;  /* EV: R-33326-45252 */}
+        break;
+      case 57: /* refact ::= CASCADE */
+{ yymsp[0].minor.yy502 = OE_Cascade;  /* EV: R-33326-45252 */}
+        break;
+      case 58: /* refact ::= RESTRICT */
+{ yymsp[0].minor.yy502 = OE_Restrict; /* EV: R-33326-45252 */}
+        break;
+      case 59: /* refact ::= NO ACTION */
+{ yymsp[-1].minor.yy502 = OE_None;     /* EV: R-33326-45252 */}
+        break;
+      case 60: /* defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt */
+{yymsp[-2].minor.yy502 = 0;}
+        break;
+      case 61: /* defer_subclause ::= DEFERRABLE init_deferred_pred_opt */
+      case 76: /* orconf ::= OR resolvetype */ yytestcase(yyruleno==76);
+      case 173: /* insert_cmd ::= INSERT orconf */ yytestcase(yyruleno==173);
+{yymsp[-1].minor.yy502 = yymsp[0].minor.yy502;}
+        break;
+      case 63: /* init_deferred_pred_opt ::= INITIALLY DEFERRED */
+      case 80: /* ifexists ::= IF EXISTS */ yytestcase(yyruleno==80);
+      case 219: /* between_op ::= NOT BETWEEN */ yytestcase(yyruleno==219);
+      case 222: /* in_op ::= NOT IN */ yytestcase(yyruleno==222);
+      case 247: /* collate ::= COLLATE ID|STRING */ yytestcase(yyruleno==247);
+{yymsp[-1].minor.yy502 = 1;}
+        break;
+      case 64: /* init_deferred_pred_opt ::= INITIALLY IMMEDIATE */
+{yymsp[-1].minor.yy502 = 0;}
+        break;
+      case 66: /* tconscomma ::= COMMA */
+{pParse->constraintName.n = 0;}
+        break;
+      case 68: /* tcons ::= PRIMARY KEY LP sortlist autoinc RP onconf */
+{sqlite3AddPrimaryKey(pParse,yymsp[-3].minor.yy402,yymsp[0].minor.yy502,yymsp[-2].minor.yy502,0);}
+        break;
+      case 69: /* tcons ::= UNIQUE LP sortlist RP onconf */
+{sqlite3CreateIndex(pParse,0,0,0,yymsp[-2].minor.yy402,yymsp[0].minor.yy502,0,0,0,0,
+                                       SQLITE_IDXTYPE_UNIQUE);}
+        break;
+      case 70: /* tcons ::= CHECK LP expr RP onconf */
+{sqlite3AddCheckConstraint(pParse,yymsp[-2].minor.yy590,yymsp[-3].minor.yy0.z,yymsp[-1].minor.yy0.z);}
+        break;
+      case 71: /* tcons ::= FOREIGN KEY LP eidlist RP REFERENCES nm eidlist_opt refargs defer_subclause_opt */
+{
+    sqlite3CreateForeignKey(pParse, yymsp[-6].minor.yy402, &yymsp[-3].minor.yy0, yymsp[-2].minor.yy402, yymsp[-1].minor.yy502);
+    sqlite3DeferForeignKey(pParse, yymsp[0].minor.yy502);
+}
+        break;
+      case 73: /* onconf ::= */
+      case 75: /* orconf ::= */ yytestcase(yyruleno==75);
+{yymsp[1].minor.yy502 = OE_Default;}
+        break;
+      case 74: /* onconf ::= ON CONFLICT resolvetype */
+{yymsp[-2].minor.yy502 = yymsp[0].minor.yy502;}
+        break;
+      case 77: /* resolvetype ::= IGNORE */
+{yymsp[0].minor.yy502 = OE_Ignore;}
+        break;
+      case 78: /* resolvetype ::= REPLACE */
+      case 174: /* insert_cmd ::= REPLACE */ yytestcase(yyruleno==174);
+{yymsp[0].minor.yy502 = OE_Replace;}
+        break;
+      case 79: /* cmd ::= DROP TABLE ifexists fullname */
+{
+  sqlite3DropTable(pParse, yymsp[0].minor.yy563, 0, yymsp[-1].minor.yy502);
+}
+        break;
+      case 82: /* cmd ::= createkw temp VIEW ifnotexists nm dbnm eidlist_opt AS select */
+{
+  sqlite3CreateView(pParse, &yymsp[-8].minor.yy0, &yymsp[-4].minor.yy0, &yymsp[-3].minor.yy0, yymsp[-2].minor.yy402, yymsp[0].minor.yy637, yymsp[-7].minor.yy502, yymsp[-5].minor.yy502);
+}
+        break;
+      case 83: /* cmd ::= DROP VIEW ifexists fullname */
+{
+  sqlite3DropTable(pParse, yymsp[0].minor.yy563, 1, yymsp[-1].minor.yy502);
+}
+        break;
+      case 84: /* cmd ::= select */
+{
+  SelectDest dest = {SRT_Output, 0, 0, 0, 0, 0, 0};
+  if( (pParse->db->mDbFlags & DBFLAG_EncodingFixed)!=0
+   || sqlite3ReadSchema(pParse)==SQLITE_OK
+  ){
+    sqlite3Select(pParse, yymsp[0].minor.yy637, &dest);
+  }
+  sqlite3SelectDelete(pParse->db, yymsp[0].minor.yy637);
+}
+        break;
+      case 85: /* select ::= WITH wqlist selectnowith */
+{yymsp[-2].minor.yy637 = attachWithToSelect(pParse,yymsp[0].minor.yy637,yymsp[-1].minor.yy125);}
+        break;
+      case 86: /* select ::= WITH RECURSIVE wqlist selectnowith */
+{yymsp[-3].minor.yy637 = attachWithToSelect(pParse,yymsp[0].minor.yy637,yymsp[-1].minor.yy125);}
+        break;
+      case 87: /* select ::= selectnowith */
+{
+  Select *p = yymsp[0].minor.yy637;
+  if( p ){
+    parserDoubleLinkSelect(pParse, p);
+  }
+}
+        break;
+      case 88: /* selectnowith ::= selectnowith multiselect_op oneselect */
+{
+  Select *pRhs = yymsp[0].minor.yy637;
+  Select *pLhs = yymsp[-2].minor.yy637;
+  if( pRhs && pRhs->pPrior ){
+    SrcList *pFrom;
+    Token x;
+    x.n = 0;
+    parserDoubleLinkSelect(pParse, pRhs);
+    pFrom = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&x,pRhs,0);
+    pRhs = sqlite3SelectNew(pParse,0,pFrom,0,0,0,0,0,0);
+  }
+  if( pRhs ){
+    pRhs->op = (u8)yymsp[-1].minor.yy502;
+    pRhs->pPrior = pLhs;
+    if( ALWAYS(pLhs) ) pLhs->selFlags &= ~SF_MultiValue;
+    pRhs->selFlags &= ~SF_MultiValue;
+    if( yymsp[-1].minor.yy502!=TK_ALL ) pParse->hasCompound = 1;
+  }else{
+    sqlite3SelectDelete(pParse->db, pLhs);
+  }
+  yymsp[-2].minor.yy637 = pRhs;
+}
+        break;
+      case 89: /* multiselect_op ::= UNION */
+      case 91: /* multiselect_op ::= EXCEPT|INTERSECT */ yytestcase(yyruleno==91);
+{yymsp[0].minor.yy502 = yymsp[0].major; /*A-overwrites-OP*/}
+        break;
+      case 90: /* multiselect_op ::= UNION ALL */
+{yymsp[-1].minor.yy502 = TK_ALL;}
+        break;
+      case 92: /* oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt */
+{
+  yymsp[-8].minor.yy637 = sqlite3SelectNew(pParse,yymsp[-6].minor.yy402,yymsp[-5].minor.yy563,yymsp[-4].minor.yy590,yymsp[-3].minor.yy402,yymsp[-2].minor.yy590,yymsp[-1].minor.yy402,yymsp[-7].minor.yy502,yymsp[0].minor.yy590);
+}
+        break;
+      case 93: /* oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt window_clause orderby_opt limit_opt */
+{
+  yymsp[-9].minor.yy637 = sqlite3SelectNew(pParse,yymsp[-7].minor.yy402,yymsp[-6].minor.yy563,yymsp[-5].minor.yy590,yymsp[-4].minor.yy402,yymsp[-3].minor.yy590,yymsp[-1].minor.yy402,yymsp[-8].minor.yy502,yymsp[0].minor.yy590);
+  if( yymsp[-9].minor.yy637 ){
+    yymsp[-9].minor.yy637->pWinDefn = yymsp[-2].minor.yy483;
+  }else{
+    sqlite3WindowListDelete(pParse->db, yymsp[-2].minor.yy483);
+  }
+}
+        break;
+      case 94: /* values ::= VALUES LP nexprlist RP */
+{
+  yymsp[-3].minor.yy637 = sqlite3SelectNew(pParse,yymsp[-1].minor.yy402,0,0,0,0,0,SF_Values,0);
+}
+        break;
+      case 95: /* oneselect ::= mvalues */
+{
+  sqlite3MultiValuesEnd(pParse, yymsp[0].minor.yy637);
+}
+        break;
+      case 96: /* mvalues ::= values COMMA LP nexprlist RP */
+      case 97: /* mvalues ::= mvalues COMMA LP nexprlist RP */ yytestcase(yyruleno==97);
+{
+  yymsp[-4].minor.yy637 = sqlite3MultiValues(pParse, yymsp[-4].minor.yy637, yymsp[-1].minor.yy402);
+}
+        break;
+      case 98: /* distinct ::= DISTINCT */
+{yymsp[0].minor.yy502 = SF_Distinct;}
+        break;
+      case 99: /* distinct ::= ALL */
+{yymsp[0].minor.yy502 = SF_All;}
+        break;
+      case 101: /* sclp ::= */
+      case 134: /* orderby_opt ::= */ yytestcase(yyruleno==134);
+      case 144: /* groupby_opt ::= */ yytestcase(yyruleno==144);
+      case 234: /* exprlist ::= */ yytestcase(yyruleno==234);
+      case 237: /* paren_exprlist ::= */ yytestcase(yyruleno==237);
+      case 242: /* eidlist_opt ::= */ yytestcase(yyruleno==242);
+{yymsp[1].minor.yy402 = 0;}
+        break;
+      case 102: /* selcollist ::= sclp scanpt expr scanpt as */
+{
+   yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse, yymsp[-4].minor.yy402, yymsp[-2].minor.yy590);
+   if( yymsp[0].minor.yy0.n>0 ) sqlite3ExprListSetName(pParse, yymsp[-4].minor.yy402, &yymsp[0].minor.yy0, 1);
+   sqlite3ExprListSetSpan(pParse,yymsp[-4].minor.yy402,yymsp[-3].minor.yy342,yymsp[-1].minor.yy342);
+}
+        break;
+      case 103: /* selcollist ::= sclp scanpt STAR */
+{
+  Expr *p = sqlite3Expr(pParse->db, TK_ASTERISK, 0);
+  sqlite3ExprSetErrorOffset(p, (int)(yymsp[0].minor.yy0.z - pParse->zTail));
+  yymsp[-2].minor.yy402 = sqlite3ExprListAppend(pParse, yymsp[-2].minor.yy402, p);
+}
+        break;
+      case 104: /* selcollist ::= sclp scanpt nm DOT STAR */
+{
+  Expr *pRight, *pLeft, *pDot;
+  pRight = sqlite3PExpr(pParse, TK_ASTERISK, 0, 0);
+  sqlite3ExprSetErrorOffset(pRight, (int)(yymsp[0].minor.yy0.z - pParse->zTail));
+  pLeft = tokenExpr(pParse, TK_ID, yymsp[-2].minor.yy0);
+  pDot = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight);
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy402, pDot);
+}
+        break;
+      case 105: /* as ::= AS nm */
+      case 117: /* dbnm ::= DOT nm */ yytestcase(yyruleno==117);
+      case 258: /* plus_num ::= PLUS INTEGER|FLOAT */ yytestcase(yyruleno==258);
+      case 259: /* minus_num ::= MINUS INTEGER|FLOAT */ yytestcase(yyruleno==259);
+{yymsp[-1].minor.yy0 = yymsp[0].minor.yy0;}
+        break;
+      case 107: /* from ::= */
+      case 110: /* stl_prefix ::= */ yytestcase(yyruleno==110);
+{yymsp[1].minor.yy563 = 0;}
+        break;
+      case 108: /* from ::= FROM seltablist */
+{
+  yymsp[-1].minor.yy563 = yymsp[0].minor.yy563;
+  sqlite3SrcListShiftJoinType(pParse,yymsp[-1].minor.yy563);
+}
+        break;
+      case 109: /* stl_prefix ::= seltablist joinop */
+{
+   if( ALWAYS(yymsp[-1].minor.yy563 && yymsp[-1].minor.yy563->nSrc>0) ) yymsp[-1].minor.yy563->a[yymsp[-1].minor.yy563->nSrc-1].fg.jointype = (u8)yymsp[0].minor.yy502;
+}
+        break;
+      case 111: /* seltablist ::= stl_prefix nm dbnm as on_using */
+{
+  yymsp[-4].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-4].minor.yy563,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0,0,&yymsp[0].minor.yy421);
+}
+        break;
+      case 112: /* seltablist ::= stl_prefix nm dbnm as indexed_by on_using */
+{
+  yymsp[-5].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-5].minor.yy563,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,0,&yymsp[0].minor.yy421);
+  sqlite3SrcListIndexedBy(pParse, yymsp[-5].minor.yy563, &yymsp[-1].minor.yy0);
+}
+        break;
+      case 113: /* seltablist ::= stl_prefix nm dbnm LP exprlist RP as on_using */
+{
+  yymsp[-7].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-7].minor.yy563,&yymsp[-6].minor.yy0,&yymsp[-5].minor.yy0,&yymsp[-1].minor.yy0,0,&yymsp[0].minor.yy421);
+  sqlite3SrcListFuncArgs(pParse, yymsp[-7].minor.yy563, yymsp[-3].minor.yy402);
+}
+        break;
+      case 114: /* seltablist ::= stl_prefix LP select RP as on_using */
+{
+    yymsp[-5].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-5].minor.yy563,0,0,&yymsp[-1].minor.yy0,yymsp[-3].minor.yy637,&yymsp[0].minor.yy421);
+  }
+        break;
+      case 115: /* seltablist ::= stl_prefix LP seltablist RP as on_using */
+{
+    if( yymsp[-5].minor.yy563==0 && yymsp[-1].minor.yy0.n==0 && yymsp[0].minor.yy421.pOn==0 && yymsp[0].minor.yy421.pUsing==0 ){
+      yymsp[-5].minor.yy563 = yymsp[-3].minor.yy563;
+    }else if( ALWAYS(yymsp[-3].minor.yy563!=0) && yymsp[-3].minor.yy563->nSrc==1 ){
+      yymsp[-5].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-5].minor.yy563,0,0,&yymsp[-1].minor.yy0,0,&yymsp[0].minor.yy421);
+      if( yymsp[-5].minor.yy563 ){
+        SrcItem *pNew = &yymsp[-5].minor.yy563->a[yymsp[-5].minor.yy563->nSrc-1];
+        SrcItem *pOld = yymsp[-3].minor.yy563->a;
+        assert( pOld->fg.fixedSchema==0 );
+        pNew->zName = pOld->zName;
+        assert( pOld->fg.fixedSchema==0 );
+        if( pOld->fg.isSubquery ){
+          pNew->fg.isSubquery = 1;
+          pNew->u4.pSubq = pOld->u4.pSubq;
+          pOld->u4.pSubq = 0;
+          pOld->fg.isSubquery = 0;
+          assert( pNew->u4.pSubq!=0 && pNew->u4.pSubq->pSelect!=0 );
+          if( (pNew->u4.pSubq->pSelect->selFlags & SF_NestedFrom)!=0 ){
+            pNew->fg.isNestedFrom = 1;
+          }
+        }else{
+          pNew->u4.zDatabase = pOld->u4.zDatabase;
+          pOld->u4.zDatabase = 0;
+        }
+        if( pOld->fg.isTabFunc ){
+          pNew->u1.pFuncArg = pOld->u1.pFuncArg;
+          pOld->u1.pFuncArg = 0;
+          pOld->fg.isTabFunc = 0;
+          pNew->fg.isTabFunc = 1;
+        }
+        pOld->zName = 0;
+      }
+      sqlite3SrcListDelete(pParse->db, yymsp[-3].minor.yy563);
+    }else{
+      Select *pSubquery;
+      sqlite3SrcListShiftJoinType(pParse,yymsp[-3].minor.yy563);
+      pSubquery = sqlite3SelectNew(pParse,0,yymsp[-3].minor.yy563,0,0,0,0,SF_NestedFrom,0);
+      yymsp[-5].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-5].minor.yy563,0,0,&yymsp[-1].minor.yy0,pSubquery,&yymsp[0].minor.yy421);
+    }
+  }
+        break;
+      case 116: /* dbnm ::= */
+      case 131: /* indexed_opt ::= */ yytestcase(yyruleno==131);
+{yymsp[1].minor.yy0.z=0; yymsp[1].minor.yy0.n=0;}
+        break;
+      case 118: /* fullname ::= nm */
+{
+  yylhsminor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[0].minor.yy0,0);
+  if( IN_RENAME_OBJECT && yylhsminor.yy563 ) sqlite3RenameTokenMap(pParse, yylhsminor.yy563->a[0].zName, &yymsp[0].minor.yy0);
+}
+  yymsp[0].minor.yy563 = yylhsminor.yy563;
+        break;
+      case 119: /* fullname ::= nm DOT nm */
+{
+  yylhsminor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0);
+  if( IN_RENAME_OBJECT && yylhsminor.yy563 ) sqlite3RenameTokenMap(pParse, yylhsminor.yy563->a[0].zName, &yymsp[0].minor.yy0);
+}
+  yymsp[-2].minor.yy563 = yylhsminor.yy563;
+        break;
+      case 120: /* xfullname ::= nm */
+{yymsp[0].minor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[0].minor.yy0,0); /*A-overwrites-X*/}
+        break;
+      case 121: /* xfullname ::= nm DOT nm */
+{yymsp[-2].minor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0); /*A-overwrites-X*/}
+        break;
+      case 122: /* xfullname ::= nm DOT nm AS nm */
+{
+   yymsp[-4].minor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[-4].minor.yy0,&yymsp[-2].minor.yy0); /*A-overwrites-X*/
+   if( yymsp[-4].minor.yy563 ) yymsp[-4].minor.yy563->a[0].zAlias = sqlite3NameFromToken(pParse->db, &yymsp[0].minor.yy0);
+}
+        break;
+      case 123: /* xfullname ::= nm AS nm */
+{
+   yymsp[-2].minor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[-2].minor.yy0,0); /*A-overwrites-X*/
+   if( yymsp[-2].minor.yy563 ) yymsp[-2].minor.yy563->a[0].zAlias = sqlite3NameFromToken(pParse->db, &yymsp[0].minor.yy0);
+}
+        break;
+      case 124: /* joinop ::= COMMA|JOIN */
+{ yymsp[0].minor.yy502 = JT_INNER; }
+        break;
+      case 125: /* joinop ::= JOIN_KW JOIN */
+{yymsp[-1].minor.yy502 = sqlite3JoinType(pParse,&yymsp[-1].minor.yy0,0,0);  /*X-overwrites-A*/}
+        break;
+      case 126: /* joinop ::= JOIN_KW nm JOIN */
+{yymsp[-2].minor.yy502 = sqlite3JoinType(pParse,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0,0); /*X-overwrites-A*/}
+        break;
+      case 127: /* joinop ::= JOIN_KW nm nm JOIN */
+{yymsp[-3].minor.yy502 = sqlite3JoinType(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0);/*X-overwrites-A*/}
+        break;
+      case 128: /* on_using ::= ON expr */
+{yymsp[-1].minor.yy421.pOn = yymsp[0].minor.yy590; yymsp[-1].minor.yy421.pUsing = 0;}
+        break;
+      case 129: /* on_using ::= USING LP idlist RP */
+{yymsp[-3].minor.yy421.pOn = 0; yymsp[-3].minor.yy421.pUsing = yymsp[-1].minor.yy204;}
+        break;
+      case 130: /* on_using ::= */
+{yymsp[1].minor.yy421.pOn = 0; yymsp[1].minor.yy421.pUsing = 0;}
+        break;
+      case 132: /* indexed_by ::= INDEXED BY nm */
+{yymsp[-2].minor.yy0 = yymsp[0].minor.yy0;}
+        break;
+      case 133: /* indexed_by ::= NOT INDEXED */
+{yymsp[-1].minor.yy0.z=0; yymsp[-1].minor.yy0.n=1;}
+        break;
+      case 135: /* orderby_opt ::= ORDER BY sortlist */
+      case 145: /* groupby_opt ::= GROUP BY nexprlist */ yytestcase(yyruleno==145);
+{yymsp[-2].minor.yy402 = yymsp[0].minor.yy402;}
+        break;
+      case 136: /* sortlist ::= sortlist COMMA expr sortorder nulls */
+{
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy402,yymsp[-2].minor.yy590);
+  sqlite3ExprListSetSortOrder(yymsp[-4].minor.yy402,yymsp[-1].minor.yy502,yymsp[0].minor.yy502);
+}
+        break;
+      case 137: /* sortlist ::= expr sortorder nulls */
+{
+  yymsp[-2].minor.yy402 = sqlite3ExprListAppend(pParse,0,yymsp[-2].minor.yy590); /*A-overwrites-Y*/
+  sqlite3ExprListSetSortOrder(yymsp[-2].minor.yy402,yymsp[-1].minor.yy502,yymsp[0].minor.yy502);
+}
+        break;
+      case 138: /* sortorder ::= ASC */
+{yymsp[0].minor.yy502 = SQLITE_SO_ASC;}
+        break;
+      case 139: /* sortorder ::= DESC */
+{yymsp[0].minor.yy502 = SQLITE_SO_DESC;}
+        break;
+      case 140: /* sortorder ::= */
+      case 143: /* nulls ::= */ yytestcase(yyruleno==143);
+{yymsp[1].minor.yy502 = SQLITE_SO_UNDEFINED;}
+        break;
+      case 141: /* nulls ::= NULLS FIRST */
+{yymsp[-1].minor.yy502 = SQLITE_SO_ASC;}
+        break;
+      case 142: /* nulls ::= NULLS LAST */
+{yymsp[-1].minor.yy502 = SQLITE_SO_DESC;}
+        break;
+      case 146: /* having_opt ::= */
+      case 148: /* limit_opt ::= */ yytestcase(yyruleno==148);
+      case 153: /* where_opt ::= */ yytestcase(yyruleno==153);
+      case 155: /* where_opt_ret ::= */ yytestcase(yyruleno==155);
+      case 232: /* case_else ::= */ yytestcase(yyruleno==232);
+      case 233: /* case_operand ::= */ yytestcase(yyruleno==233);
+      case 252: /* vinto ::= */ yytestcase(yyruleno==252);
+{yymsp[1].minor.yy590 = 0;}
+        break;
+      case 147: /* having_opt ::= HAVING expr */
+      case 154: /* where_opt ::= WHERE expr */ yytestcase(yyruleno==154);
+      case 156: /* where_opt_ret ::= WHERE expr */ yytestcase(yyruleno==156);
+      case 231: /* case_else ::= ELSE expr */ yytestcase(yyruleno==231);
+      case 251: /* vinto ::= INTO expr */ yytestcase(yyruleno==251);
+{yymsp[-1].minor.yy590 = yymsp[0].minor.yy590;}
+        break;
+      case 149: /* limit_opt ::= LIMIT expr */
+{yymsp[-1].minor.yy590 = sqlite3PExpr(pParse,TK_LIMIT,yymsp[0].minor.yy590,0);}
+        break;
+      case 150: /* limit_opt ::= LIMIT expr OFFSET expr */
+{yymsp[-3].minor.yy590 = sqlite3PExpr(pParse,TK_LIMIT,yymsp[-2].minor.yy590,yymsp[0].minor.yy590);}
+        break;
+      case 151: /* limit_opt ::= LIMIT expr COMMA expr */
+{yymsp[-3].minor.yy590 = sqlite3PExpr(pParse,TK_LIMIT,yymsp[0].minor.yy590,yymsp[-2].minor.yy590);}
+        break;
+      case 152: /* cmd ::= with DELETE FROM xfullname indexed_opt where_opt_ret orderby_opt limit_opt */
+{
+  sqlite3SrcListIndexedBy(pParse, yymsp[-4].minor.yy563, &yymsp[-3].minor.yy0);
+#ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( yymsp[-1].minor.yy402 || yymsp[0].minor.yy590 ){
+    updateDeleteLimitError(pParse,yymsp[-1].minor.yy402,yymsp[0].minor.yy590);
+    yymsp[-1].minor.yy402 = 0;
+    yymsp[0].minor.yy590 = 0;
+  }
+#endif
+  sqlite3DeleteFrom(pParse,yymsp[-4].minor.yy563,yymsp[-2].minor.yy590,yymsp[-1].minor.yy402,yymsp[0].minor.yy590);
+}
+        break;
+      case 157: /* where_opt_ret ::= RETURNING selcollist */
+{sqlite3AddReturning(pParse,yymsp[0].minor.yy402); yymsp[-1].minor.yy590 = 0;}
+        break;
+      case 158: /* where_opt_ret ::= WHERE expr RETURNING selcollist */
+{sqlite3AddReturning(pParse,yymsp[0].minor.yy402); yymsp[-3].minor.yy590 = yymsp[-2].minor.yy590;}
+        break;
+      case 159: /* cmd ::= with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret orderby_opt limit_opt */
+{
+  sqlite3SrcListIndexedBy(pParse, yymsp[-7].minor.yy563, &yymsp[-6].minor.yy0);
+  if( yymsp[-3].minor.yy563 ){
+    SrcList *pFromClause = yymsp[-3].minor.yy563;
+    if( pFromClause->nSrc>1 ){
+      Select *pSubquery;
+      Token as;
+      pSubquery = sqlite3SelectNew(pParse,0,pFromClause,0,0,0,0,SF_NestedFrom,0);
+      as.n = 0;
+      as.z = 0;
+      pFromClause = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&as,pSubquery,0);
+    }
+    yymsp[-7].minor.yy563 = sqlite3SrcListAppendList(pParse, yymsp[-7].minor.yy563, pFromClause);
+  }
+  sqlite3ExprListCheckLength(pParse,yymsp[-4].minor.yy402,"set list");
+#ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( yymsp[-1].minor.yy402 || yymsp[0].minor.yy590 ){
+    updateDeleteLimitError(pParse,yymsp[-1].minor.yy402,yymsp[0].minor.yy590);
+    yymsp[-1].minor.yy402 = 0;
+    yymsp[0].minor.yy590 = 0;
+  }
+#endif
+  sqlite3Update(pParse,yymsp[-7].minor.yy563,yymsp[-4].minor.yy402,yymsp[-2].minor.yy590,yymsp[-8].minor.yy502,yymsp[-1].minor.yy402,yymsp[0].minor.yy590,0);
+}
+        break;
+      case 160: /* setlist ::= setlist COMMA nm EQ expr */
+{
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse, yymsp[-4].minor.yy402, yymsp[0].minor.yy590);
+  sqlite3ExprListSetName(pParse, yymsp[-4].minor.yy402, &yymsp[-2].minor.yy0, 1);
+}
+        break;
+      case 161: /* setlist ::= setlist COMMA LP idlist RP EQ expr */
+{
+  yymsp[-6].minor.yy402 = sqlite3ExprListAppendVector(pParse, yymsp[-6].minor.yy402, yymsp[-3].minor.yy204, yymsp[0].minor.yy590);
+}
+        break;
+      case 162: /* setlist ::= nm EQ expr */
+{
+  yylhsminor.yy402 = sqlite3ExprListAppend(pParse, 0, yymsp[0].minor.yy590);
+  sqlite3ExprListSetName(pParse, yylhsminor.yy402, &yymsp[-2].minor.yy0, 1);
+}
+  yymsp[-2].minor.yy402 = yylhsminor.yy402;
+        break;
+      case 163: /* setlist ::= LP idlist RP EQ expr */
+{
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppendVector(pParse, 0, yymsp[-3].minor.yy204, yymsp[0].minor.yy590);
+}
+        break;
+      case 164: /* cmd ::= with insert_cmd INTO xfullname idlist_opt select upsert */
+{
+  sqlite3Insert(pParse, yymsp[-3].minor.yy563, yymsp[-1].minor.yy637, yymsp[-2].minor.yy204, yymsp[-5].minor.yy502, yymsp[0].minor.yy403);
+}
+        break;
+      case 165: /* cmd ::= with insert_cmd INTO xfullname idlist_opt DEFAULT VALUES returning */
+{
+  sqlite3Insert(pParse, yymsp[-4].minor.yy563, 0, yymsp[-3].minor.yy204, yymsp[-6].minor.yy502, 0);
+}
+        break;
+      case 166: /* upsert ::= */
+{ yymsp[1].minor.yy403 = 0; }
+        break;
+      case 167: /* upsert ::= RETURNING selcollist */
+{ yymsp[-1].minor.yy403 = 0; sqlite3AddReturning(pParse,yymsp[0].minor.yy402); }
+        break;
+      case 168: /* upsert ::= ON CONFLICT LP sortlist RP where_opt DO UPDATE SET setlist where_opt upsert */
+{ yymsp[-11].minor.yy403 = sqlite3UpsertNew(pParse->db,yymsp[-8].minor.yy402,yymsp[-6].minor.yy590,yymsp[-2].minor.yy402,yymsp[-1].minor.yy590,yymsp[0].minor.yy403);}
+        break;
+      case 169: /* upsert ::= ON CONFLICT LP sortlist RP where_opt DO NOTHING upsert */
+{ yymsp[-8].minor.yy403 = sqlite3UpsertNew(pParse->db,yymsp[-5].minor.yy402,yymsp[-3].minor.yy590,0,0,yymsp[0].minor.yy403); }
+        break;
+      case 170: /* upsert ::= ON CONFLICT DO NOTHING returning */
+{ yymsp[-4].minor.yy403 = sqlite3UpsertNew(pParse->db,0,0,0,0,0); }
+        break;
+      case 171: /* upsert ::= ON CONFLICT DO UPDATE SET setlist where_opt returning */
+{ yymsp[-7].minor.yy403 = sqlite3UpsertNew(pParse->db,0,0,yymsp[-2].minor.yy402,yymsp[-1].minor.yy590,0);}
+        break;
+      case 172: /* returning ::= RETURNING selcollist */
+{sqlite3AddReturning(pParse,yymsp[0].minor.yy402);}
+        break;
+      case 175: /* idlist_opt ::= */
+{yymsp[1].minor.yy204 = 0;}
+        break;
+      case 176: /* idlist_opt ::= LP idlist RP */
+{yymsp[-2].minor.yy204 = yymsp[-1].minor.yy204;}
+        break;
+      case 177: /* idlist ::= idlist COMMA nm */
+{yymsp[-2].minor.yy204 = sqlite3IdListAppend(pParse,yymsp[-2].minor.yy204,&yymsp[0].minor.yy0);}
+        break;
+      case 178: /* idlist ::= nm */
+{yymsp[0].minor.yy204 = sqlite3IdListAppend(pParse,0,&yymsp[0].minor.yy0); /*A-overwrites-Y*/}
+        break;
+      case 179: /* expr ::= LP expr RP */
+{yymsp[-2].minor.yy590 = yymsp[-1].minor.yy590;}
+        break;
+      case 180: /* expr ::= ID|INDEXED|JOIN_KW */
+{yymsp[0].minor.yy590=tokenExpr(pParse,TK_ID,yymsp[0].minor.yy0); /*A-overwrites-X*/}
+        break;
+      case 181: /* expr ::= nm DOT nm */
+{
+  Expr *temp1 = tokenExpr(pParse,TK_ID,yymsp[-2].minor.yy0);
+  Expr *temp2 = tokenExpr(pParse,TK_ID,yymsp[0].minor.yy0);
+  yylhsminor.yy590 = sqlite3PExpr(pParse, TK_DOT, temp1, temp2);
+}
+  yymsp[-2].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 182: /* expr ::= nm DOT nm DOT nm */
+{
+  Expr *temp1 = tokenExpr(pParse,TK_ID,yymsp[-4].minor.yy0);
+  Expr *temp2 = tokenExpr(pParse,TK_ID,yymsp[-2].minor.yy0);
+  Expr *temp3 = tokenExpr(pParse,TK_ID,yymsp[0].minor.yy0);
+  Expr *temp4 = sqlite3PExpr(pParse, TK_DOT, temp2, temp3);
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameTokenRemap(pParse, 0, temp1);
+  }
+  yylhsminor.yy590 = sqlite3PExpr(pParse, TK_DOT, temp1, temp4);
+}
+  yymsp[-4].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 183: /* term ::= NULL|FLOAT|BLOB */
+      case 184: /* term ::= STRING */ yytestcase(yyruleno==184);
+{yymsp[0].minor.yy590=tokenExpr(pParse,yymsp[0].major,yymsp[0].minor.yy0); /*A-overwrites-X*/}
+        break;
+      case 185: /* term ::= INTEGER */
+{
+  yylhsminor.yy590 = sqlite3ExprAlloc(pParse->db, TK_INTEGER, &yymsp[0].minor.yy0, 1);
+  if( yylhsminor.yy590 ) yylhsminor.yy590->w.iOfst = (int)(yymsp[0].minor.yy0.z - pParse->zTail);
+}
+  yymsp[0].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 186: /* expr ::= VARIABLE */
+{
+  if( !(yymsp[0].minor.yy0.z[0]=='#' && sqlite3Isdigit(yymsp[0].minor.yy0.z[1])) ){
+    u32 n = yymsp[0].minor.yy0.n;
+    yymsp[0].minor.yy590 = tokenExpr(pParse, TK_VARIABLE, yymsp[0].minor.yy0);
+    sqlite3ExprAssignVarNumber(pParse, yymsp[0].minor.yy590, n);
+  }else{
+    /* When doing a nested parse, one can include terms in an expression
+    ** that look like this:   #1 #2 ...  These terms refer to registers
+    ** in the virtual machine.  #N is the N-th register. */
+    Token t = yymsp[0].minor.yy0; /*A-overwrites-X*/
+    assert( t.n>=2 );
+    if( pParse->nested==0 ){
+      parserSyntaxError(pParse, &t);
+      yymsp[0].minor.yy590 = 0;
+    }else{
+      yymsp[0].minor.yy590 = sqlite3PExpr(pParse, TK_REGISTER, 0, 0);
+      if( yymsp[0].minor.yy590 ) sqlite3GetInt32(&t.z[1], &yymsp[0].minor.yy590->iTable);
+    }
+  }
+}
+        break;
+      case 187: /* expr ::= expr COLLATE ID|STRING */
+{
+  yymsp[-2].minor.yy590 = sqlite3ExprAddCollateToken(pParse, yymsp[-2].minor.yy590, &yymsp[0].minor.yy0, 1);
+}
+        break;
+      case 188: /* expr ::= CAST LP expr AS typetoken RP */
+{
+  yymsp[-5].minor.yy590 = sqlite3ExprAlloc(pParse->db, TK_CAST, &yymsp[-1].minor.yy0, 1);
+  sqlite3ExprAttachSubtrees(pParse->db, yymsp[-5].minor.yy590, yymsp[-3].minor.yy590, 0);
+}
+        break;
+      case 189: /* expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, yymsp[-1].minor.yy402, &yymsp[-4].minor.yy0, yymsp[-2].minor.yy502);
+}
+  yymsp[-4].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 190: /* expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, yymsp[-4].minor.yy402, &yymsp[-7].minor.yy0, yymsp[-5].minor.yy502);
+  sqlite3ExprAddFunctionOrderBy(pParse, yylhsminor.yy590, yymsp[-1].minor.yy402);
+}
+  yymsp[-7].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 191: /* expr ::= ID|INDEXED|JOIN_KW LP STAR RP */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, 0, &yymsp[-3].minor.yy0, 0);
+}
+  yymsp[-3].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 192: /* expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP filter_over */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, yymsp[-2].minor.yy402, &yymsp[-5].minor.yy0, yymsp[-3].minor.yy502);
+  sqlite3WindowAttach(pParse, yylhsminor.yy590, yymsp[0].minor.yy483);
+}
+  yymsp[-5].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 193: /* expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP filter_over */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, yymsp[-5].minor.yy402, &yymsp[-8].minor.yy0, yymsp[-6].minor.yy502);
+  sqlite3WindowAttach(pParse, yylhsminor.yy590, yymsp[0].minor.yy483);
+  sqlite3ExprAddFunctionOrderBy(pParse, yylhsminor.yy590, yymsp[-2].minor.yy402);
+}
+  yymsp[-8].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 194: /* expr ::= ID|INDEXED|JOIN_KW LP STAR RP filter_over */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, 0, &yymsp[-4].minor.yy0, 0);
+  sqlite3WindowAttach(pParse, yylhsminor.yy590, yymsp[0].minor.yy483);
+}
+  yymsp[-4].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 195: /* term ::= CTIME_KW */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, 0, &yymsp[0].minor.yy0, 0);
+}
+  yymsp[0].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 196: /* expr ::= LP nexprlist COMMA expr RP */
+{
+  ExprList *pList = sqlite3ExprListAppend(pParse, yymsp[-3].minor.yy402, yymsp[-1].minor.yy590);
+  yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_VECTOR, 0, 0);
+  if( yymsp[-4].minor.yy590 ){
+    yymsp[-4].minor.yy590->x.pList = pList;
+    if( ALWAYS(pList->nExpr) ){
+      yymsp[-4].minor.yy590->flags |= pList->a[0].pExpr->flags & EP_Propagate;
+    }
+  }else{
+    sqlite3ExprListDelete(pParse->db, pList);
+  }
+}
+        break;
+      case 197: /* expr ::= expr AND expr */
+{yymsp[-2].minor.yy590=sqlite3ExprAnd(pParse,yymsp[-2].minor.yy590,yymsp[0].minor.yy590);}
+        break;
+      case 198: /* expr ::= expr OR expr */
+      case 199: /* expr ::= expr LT|GT|GE|LE expr */ yytestcase(yyruleno==199);
+      case 200: /* expr ::= expr EQ|NE expr */ yytestcase(yyruleno==200);
+      case 201: /* expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr */ yytestcase(yyruleno==201);
+      case 202: /* expr ::= expr PLUS|MINUS expr */ yytestcase(yyruleno==202);
+      case 203: /* expr ::= expr STAR|SLASH|REM expr */ yytestcase(yyruleno==203);
+      case 204: /* expr ::= expr CONCAT expr */ yytestcase(yyruleno==204);
+{yymsp[-2].minor.yy590=sqlite3PExpr(pParse,yymsp[-1].major,yymsp[-2].minor.yy590,yymsp[0].minor.yy590);}
+        break;
+      case 205: /* likeop ::= NOT LIKE_KW|MATCH */
+{yymsp[-1].minor.yy0=yymsp[0].minor.yy0; yymsp[-1].minor.yy0.n|=0x80000000; /*yymsp[-1].minor.yy0-overwrite-yymsp[0].minor.yy0*/}
+        break;
+      case 206: /* expr ::= expr likeop expr */
+{
+  ExprList *pList;
+  int bNot = yymsp[-1].minor.yy0.n & 0x80000000;
+  yymsp[-1].minor.yy0.n &= 0x7fffffff;
+  pList = sqlite3ExprListAppend(pParse,0, yymsp[0].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[-2].minor.yy590);
+  yymsp[-2].minor.yy590 = sqlite3ExprFunction(pParse, pList, &yymsp[-1].minor.yy0, 0);
+  if( bNot ) yymsp[-2].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-2].minor.yy590, 0);
+  if( yymsp[-2].minor.yy590 ) yymsp[-2].minor.yy590->flags |= EP_InfixFunc;
+}
+        break;
+      case 207: /* expr ::= expr likeop expr ESCAPE expr */
+{
+  ExprList *pList;
+  int bNot = yymsp[-3].minor.yy0.n & 0x80000000;
+  yymsp[-3].minor.yy0.n &= 0x7fffffff;
+  pList = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[-4].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy590);
+  yymsp[-4].minor.yy590 = sqlite3ExprFunction(pParse, pList, &yymsp[-3].minor.yy0, 0);
+  if( bNot ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+  if( yymsp[-4].minor.yy590 ) yymsp[-4].minor.yy590->flags |= EP_InfixFunc;
+}
+        break;
+      case 208: /* expr ::= expr ISNULL|NOTNULL */
+{yymsp[-1].minor.yy590 = sqlite3PExpr(pParse,yymsp[0].major,yymsp[-1].minor.yy590,0);}
+        break;
+      case 209: /* expr ::= expr NOT NULL */
+{yymsp[-2].minor.yy590 = sqlite3PExpr(pParse,TK_NOTNULL,yymsp[-2].minor.yy590,0);}
+        break;
+      case 210: /* expr ::= expr IS expr */
+{
+  yymsp[-2].minor.yy590 = sqlite3PExpr(pParse,TK_IS,yymsp[-2].minor.yy590,yymsp[0].minor.yy590);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy590, yymsp[-2].minor.yy590, TK_ISNULL);
+}
+        break;
+      case 211: /* expr ::= expr IS NOT expr */
+{
+  yymsp[-3].minor.yy590 = sqlite3PExpr(pParse,TK_ISNOT,yymsp[-3].minor.yy590,yymsp[0].minor.yy590);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy590, yymsp[-3].minor.yy590, TK_NOTNULL);
+}
+        break;
+      case 212: /* expr ::= expr IS NOT DISTINCT FROM expr */
+{
+  yymsp[-5].minor.yy590 = sqlite3PExpr(pParse,TK_IS,yymsp[-5].minor.yy590,yymsp[0].minor.yy590);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy590, yymsp[-5].minor.yy590, TK_ISNULL);
+}
+        break;
+      case 213: /* expr ::= expr IS DISTINCT FROM expr */
+{
+  yymsp[-4].minor.yy590 = sqlite3PExpr(pParse,TK_ISNOT,yymsp[-4].minor.yy590,yymsp[0].minor.yy590);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy590, yymsp[-4].minor.yy590, TK_NOTNULL);
+}
+        break;
+      case 214: /* expr ::= NOT expr */
+      case 215: /* expr ::= BITNOT expr */ yytestcase(yyruleno==215);
+{yymsp[-1].minor.yy590 = sqlite3PExpr(pParse, yymsp[-1].major, yymsp[0].minor.yy590, 0);/*A-overwrites-B*/}
+        break;
+      case 216: /* expr ::= PLUS|MINUS expr */
+{
+  Expr *p = yymsp[0].minor.yy590;
+  u8 op = yymsp[-1].major + (TK_UPLUS-TK_PLUS);
+  assert( TK_UPLUS>TK_PLUS );
+  assert( TK_UMINUS == TK_MINUS + (TK_UPLUS - TK_PLUS) );
+  if( p && p->op==TK_UPLUS ){
+    p->op = op;
+    yymsp[-1].minor.yy590 = p;
+  }else{
+    yymsp[-1].minor.yy590 = sqlite3PExpr(pParse, op, p, 0);
+    /*A-overwrites-B*/
+  }
+}
+        break;
+      case 217: /* expr ::= expr PTR expr */
+{
+  ExprList *pList = sqlite3ExprListAppend(pParse, 0, yymsp[-2].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse, pList, yymsp[0].minor.yy590);
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, pList, &yymsp[-1].minor.yy0, 0);
+}
+  yymsp[-2].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 218: /* between_op ::= BETWEEN */
+      case 221: /* in_op ::= IN */ yytestcase(yyruleno==221);
+{yymsp[0].minor.yy502 = 0;}
+        break;
+      case 220: /* expr ::= expr between_op expr AND expr */
+{
+  ExprList *pList = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy590);
+  yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_BETWEEN, yymsp[-4].minor.yy590, 0);
+  if( yymsp[-4].minor.yy590 ){
+    yymsp[-4].minor.yy590->x.pList = pList;
+  }else{
+    sqlite3ExprListDelete(pParse->db, pList);
+  }
+  if( yymsp[-3].minor.yy502 ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+}
+        break;
+      case 223: /* expr ::= expr in_op LP exprlist RP */
+{
+    if( yymsp[-1].minor.yy402==0 ){
+      /* Expressions of the form
+      **
+      **      expr1 IN ()
+      **      expr1 NOT IN ()
+      **
+      ** simplify to constants 0 (false) and 1 (true), respectively,
+      ** regardless of the value of expr1.
+      */
+      sqlite3ExprUnmapAndDelete(pParse, yymsp[-4].minor.yy590);
+      yymsp[-4].minor.yy590 = sqlite3Expr(pParse->db, TK_STRING, yymsp[-3].minor.yy502 ? "true" : "false");
+      if( yymsp[-4].minor.yy590 ) sqlite3ExprIdToTrueFalse(yymsp[-4].minor.yy590);
+    }else{
+      Expr *pRHS = yymsp[-1].minor.yy402->a[0].pExpr;
+      if( yymsp[-1].minor.yy402->nExpr==1 && sqlite3ExprIsConstant(pParse,pRHS) && yymsp[-4].minor.yy590->op!=TK_VECTOR ){
+        yymsp[-1].minor.yy402->a[0].pExpr = 0;
+        sqlite3ExprListDelete(pParse->db, yymsp[-1].minor.yy402);
+        pRHS = sqlite3PExpr(pParse, TK_UPLUS, pRHS, 0);
+        yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_EQ, yymsp[-4].minor.yy590, pRHS);
+      }else if( yymsp[-1].minor.yy402->nExpr==1 && pRHS->op==TK_SELECT ){
+        yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy590, 0);
+        sqlite3PExprAddSelect(pParse, yymsp[-4].minor.yy590, pRHS->x.pSelect);
+        pRHS->x.pSelect = 0;
+        sqlite3ExprListDelete(pParse->db, yymsp[-1].minor.yy402);
+      }else{
+        yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy590, 0);
+        if( yymsp[-4].minor.yy590==0 ){
+          sqlite3ExprListDelete(pParse->db, yymsp[-1].minor.yy402);
+        }else if( yymsp[-4].minor.yy590->pLeft->op==TK_VECTOR ){
+          int nExpr = yymsp[-4].minor.yy590->pLeft->x.pList->nExpr;
+          Select *pSelectRHS = sqlite3ExprListToValues(pParse, nExpr, yymsp[-1].minor.yy402);
+          if( pSelectRHS ){
+            parserDoubleLinkSelect(pParse, pSelectRHS);
+            sqlite3PExprAddSelect(pParse, yymsp[-4].minor.yy590, pSelectRHS);
+          }
+        }else{
+          yymsp[-4].minor.yy590->x.pList = yymsp[-1].minor.yy402;
+          sqlite3ExprSetHeightAndFlags(pParse, yymsp[-4].minor.yy590);
+        }
+      }
+      if( yymsp[-3].minor.yy502 ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+    }
+  }
+        break;
+      case 224: /* expr ::= LP select RP */
+{
+    yymsp[-2].minor.yy590 = sqlite3PExpr(pParse, TK_SELECT, 0, 0);
+    sqlite3PExprAddSelect(pParse, yymsp[-2].minor.yy590, yymsp[-1].minor.yy637);
+  }
+        break;
+      case 225: /* expr ::= expr in_op LP select RP */
+{
+    yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy590, 0);
+    sqlite3PExprAddSelect(pParse, yymsp[-4].minor.yy590, yymsp[-1].minor.yy637);
+    if( yymsp[-3].minor.yy502 ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+  }
+        break;
+      case 226: /* expr ::= expr in_op nm dbnm paren_exprlist */
+{
+    SrcList *pSrc = sqlite3SrcListAppend(pParse, 0,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0);
+    Select *pSelect = sqlite3SelectNew(pParse, 0,pSrc,0,0,0,0,0,0);
+    if( yymsp[0].minor.yy402 )  sqlite3SrcListFuncArgs(pParse, pSelect ? pSrc : 0, yymsp[0].minor.yy402);
+    yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy590, 0);
+    sqlite3PExprAddSelect(pParse, yymsp[-4].minor.yy590, pSelect);
+    if( yymsp[-3].minor.yy502 ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+  }
+        break;
+      case 227: /* expr ::= EXISTS LP select RP */
+{
+    Expr *p;
+    p = yymsp[-3].minor.yy590 = sqlite3PExpr(pParse, TK_EXISTS, 0, 0);
+    sqlite3PExprAddSelect(pParse, p, yymsp[-1].minor.yy637);
+  }
+        break;
+      case 228: /* expr ::= CASE case_operand case_exprlist case_else END */
+{
+  yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_CASE, yymsp[-3].minor.yy590, 0);
+  if( yymsp[-4].minor.yy590 ){
+    yymsp[-4].minor.yy590->x.pList = yymsp[-1].minor.yy590 ? sqlite3ExprListAppend(pParse,yymsp[-2].minor.yy402,yymsp[-1].minor.yy590) : yymsp[-2].minor.yy402;
+    sqlite3ExprSetHeightAndFlags(pParse, yymsp[-4].minor.yy590);
+  }else{
+    sqlite3ExprListDelete(pParse->db, yymsp[-2].minor.yy402);
+    sqlite3ExprDelete(pParse->db, yymsp[-1].minor.yy590);
+  }
+}
+        break;
+      case 229: /* case_exprlist ::= case_exprlist WHEN expr THEN expr */
+{
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy402, yymsp[-2].minor.yy590);
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy402, yymsp[0].minor.yy590);
+}
+        break;
+      case 230: /* case_exprlist ::= WHEN expr THEN expr */
+{
+  yymsp[-3].minor.yy402 = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy590);
+  yymsp[-3].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-3].minor.yy402, yymsp[0].minor.yy590);
+}
+        break;
+      case 235: /* nexprlist ::= nexprlist COMMA expr */
+{yymsp[-2].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-2].minor.yy402,yymsp[0].minor.yy590);}
+        break;
+      case 236: /* nexprlist ::= expr */
+{yymsp[0].minor.yy402 = sqlite3ExprListAppend(pParse,0,yymsp[0].minor.yy590); /*A-overwrites-Y*/}
+        break;
+      case 238: /* paren_exprlist ::= LP exprlist RP */
+      case 243: /* eidlist_opt ::= LP eidlist RP */ yytestcase(yyruleno==243);
+{yymsp[-2].minor.yy402 = yymsp[-1].minor.yy402;}
+        break;
+      case 239: /* cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP sortlist RP where_opt */
+{
+  sqlite3CreateIndex(pParse, &yymsp[-7].minor.yy0, &yymsp[-6].minor.yy0,
+                     sqlite3SrcListAppend(pParse,0,&yymsp[-4].minor.yy0,0), yymsp[-2].minor.yy402, yymsp[-10].minor.yy502,
+                      &yymsp[-11].minor.yy0, yymsp[0].minor.yy590, SQLITE_SO_ASC, yymsp[-8].minor.yy502, SQLITE_IDXTYPE_APPDEF);
+  if( IN_RENAME_OBJECT && pParse->pNewIndex ){
+    sqlite3RenameTokenMap(pParse, pParse->pNewIndex->zName, &yymsp[-4].minor.yy0);
+  }
+}
+        break;
+      case 240: /* uniqueflag ::= UNIQUE */
+      case 282: /* raisetype ::= ABORT */ yytestcase(yyruleno==282);
+{yymsp[0].minor.yy502 = OE_Abort;}
+        break;
+      case 241: /* uniqueflag ::= */
+{yymsp[1].minor.yy502 = OE_None;}
+        break;
+      case 244: /* eidlist ::= eidlist COMMA nm collate sortorder */
+{
+  yymsp[-4].minor.yy402 = parserAddExprIdListTerm(pParse, yymsp[-4].minor.yy402, &yymsp[-2].minor.yy0, yymsp[-1].minor.yy502, yymsp[0].minor.yy502);
+}
+        break;
+      case 245: /* eidlist ::= nm collate sortorder */
+{
+  yymsp[-2].minor.yy402 = parserAddExprIdListTerm(pParse, 0, &yymsp[-2].minor.yy0, yymsp[-1].minor.yy502, yymsp[0].minor.yy502); /*A-overwrites-Y*/
+}
+        break;
+      case 248: /* cmd ::= DROP INDEX ifexists fullname */
+{sqlite3DropIndex(pParse, yymsp[0].minor.yy563, yymsp[-1].minor.yy502);}
+        break;
+      case 249: /* cmd ::= VACUUM vinto */
+{sqlite3Vacuum(pParse,0,yymsp[0].minor.yy590);}
+        break;
+      case 250: /* cmd ::= VACUUM nm vinto */
+{sqlite3Vacuum(pParse,&yymsp[-1].minor.yy0,yymsp[0].minor.yy590);}
+        break;
+      case 253: /* cmd ::= PRAGMA nm dbnm */
+{sqlite3Pragma(pParse,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy0,0,0);}
+        break;
+      case 254: /* cmd ::= PRAGMA nm dbnm EQ nmnum */
+{sqlite3Pragma(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0,0);}
+        break;
+      case 255: /* cmd ::= PRAGMA nm dbnm LP nmnum RP */
+{sqlite3Pragma(pParse,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,&yymsp[-1].minor.yy0,0);}
+        break;
+      case 256: /* cmd ::= PRAGMA nm dbnm EQ minus_num */
+{sqlite3Pragma(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0,1);}
+        break;
+      case 257: /* cmd ::= PRAGMA nm dbnm LP minus_num RP */
+{sqlite3Pragma(pParse,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,&yymsp[-1].minor.yy0,1);}
+        break;
+      case 260: /* cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END */
+{
+  Token all;
+  all.z = yymsp[-3].minor.yy0.z;
+  all.n = (int)(yymsp[0].minor.yy0.z - yymsp[-3].minor.yy0.z) + yymsp[0].minor.yy0.n;
+  sqlite3FinishTrigger(pParse, yymsp[-1].minor.yy319, &all);
+}
+        break;
+      case 261: /* trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause */
+{
+  sqlite3BeginTrigger(pParse, &yymsp[-7].minor.yy0, &yymsp[-6].minor.yy0, yymsp[-5].minor.yy502, yymsp[-4].minor.yy28.a, yymsp[-4].minor.yy28.b, yymsp[-2].minor.yy563, yymsp[0].minor.yy590, yymsp[-10].minor.yy502, yymsp[-8].minor.yy502);
+  yymsp[-10].minor.yy0 = (yymsp[-6].minor.yy0.n==0?yymsp[-7].minor.yy0:yymsp[-6].minor.yy0); /*A-overwrites-T*/
+}
+        break;
+      case 262: /* trigger_time ::= BEFORE|AFTER */
+{ yymsp[0].minor.yy502 = yymsp[0].major; /*A-overwrites-X*/ }
+        break;
+      case 263: /* trigger_time ::= INSTEAD OF */
+{ yymsp[-1].minor.yy502 = TK_INSTEAD;}
+        break;
+      case 264: /* trigger_time ::= */
+{ yymsp[1].minor.yy502 = TK_BEFORE; }
+        break;
+      case 265: /* trigger_event ::= DELETE|INSERT */
+      case 266: /* trigger_event ::= UPDATE */ yytestcase(yyruleno==266);
+{yymsp[0].minor.yy28.a = yymsp[0].major; /*A-overwrites-X*/ yymsp[0].minor.yy28.b = 0;}
+        break;
+      case 267: /* trigger_event ::= UPDATE OF idlist */
+{yymsp[-2].minor.yy28.a = TK_UPDATE; yymsp[-2].minor.yy28.b = yymsp[0].minor.yy204;}
+        break;
+      case 268: /* when_clause ::= */
+      case 287: /* key_opt ::= */ yytestcase(yyruleno==287);
+{ yymsp[1].minor.yy590 = 0; }
+        break;
+      case 269: /* when_clause ::= WHEN expr */
+      case 288: /* key_opt ::= KEY expr */ yytestcase(yyruleno==288);
+{ yymsp[-1].minor.yy590 = yymsp[0].minor.yy590; }
+        break;
+      case 270: /* trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI */
+{
+  assert( yymsp[-2].minor.yy319!=0 );
+  yymsp[-2].minor.yy319->pLast->pNext = yymsp[-1].minor.yy319;
+  yymsp[-2].minor.yy319->pLast = yymsp[-1].minor.yy319;
+}
+        break;
+      case 271: /* trigger_cmd_list ::= trigger_cmd SEMI */
+{
+  assert( yymsp[-1].minor.yy319!=0 );
+  yymsp[-1].minor.yy319->pLast = yymsp[-1].minor.yy319;
+}
+        break;
+      case 272: /* trnm ::= nm DOT nm */
+{
+  yymsp[-2].minor.yy0 = yymsp[0].minor.yy0;
+  sqlite3ErrorMsg(pParse,
+        "qualified table names are not allowed on INSERT, UPDATE, and DELETE "
+        "statements within triggers");
+}
+        break;
+      case 273: /* tridxby ::= INDEXED BY nm */
+{
+  sqlite3ErrorMsg(pParse,
+        "the INDEXED BY clause is not allowed on UPDATE or DELETE statements "
+        "within triggers");
+}
+        break;
+      case 274: /* tridxby ::= NOT INDEXED */
+{
+  sqlite3ErrorMsg(pParse,
+        "the NOT INDEXED clause is not allowed on UPDATE or DELETE statements "
+        "within triggers");
+}
+        break;
+      case 275: /* trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist from where_opt scanpt */
+{yylhsminor.yy319 = sqlite3TriggerUpdateStep(pParse, &yymsp[-6].minor.yy0, yymsp[-2].minor.yy563, yymsp[-3].minor.yy402, yymsp[-1].minor.yy590, yymsp[-7].minor.yy502, yymsp[-8].minor.yy0.z, yymsp[0].minor.yy342);}
+  yymsp[-8].minor.yy319 = yylhsminor.yy319;
+        break;
+      case 276: /* trigger_cmd ::= scanpt insert_cmd INTO trnm idlist_opt select upsert scanpt */
+{
+   yylhsminor.yy319 = sqlite3TriggerInsertStep(pParse,&yymsp[-4].minor.yy0,yymsp[-3].minor.yy204,yymsp[-2].minor.yy637,yymsp[-6].minor.yy502,yymsp[-1].minor.yy403,yymsp[-7].minor.yy342,yymsp[0].minor.yy342);/*yylhsminor.yy319-overwrites-yymsp[-6].minor.yy502*/
+}
+  yymsp[-7].minor.yy319 = yylhsminor.yy319;
+        break;
+      case 277: /* trigger_cmd ::= DELETE FROM trnm tridxby where_opt scanpt */
+{yylhsminor.yy319 = sqlite3TriggerDeleteStep(pParse, &yymsp[-3].minor.yy0, yymsp[-1].minor.yy590, yymsp[-5].minor.yy0.z, yymsp[0].minor.yy342);}
+  yymsp[-5].minor.yy319 = yylhsminor.yy319;
+        break;
+      case 278: /* trigger_cmd ::= scanpt select scanpt */
+{yylhsminor.yy319 = sqlite3TriggerSelectStep(pParse->db, yymsp[-1].minor.yy637, yymsp[-2].minor.yy342, yymsp[0].minor.yy342); /*yylhsminor.yy319-overwrites-yymsp[-1].minor.yy637*/}
+  yymsp[-2].minor.yy319 = yylhsminor.yy319;
+        break;
+      case 279: /* expr ::= RAISE LP IGNORE RP */
+{
+  yymsp[-3].minor.yy590 = sqlite3PExpr(pParse, TK_RAISE, 0, 0);
+  if( yymsp[-3].minor.yy590 ){
+    yymsp[-3].minor.yy590->affExpr = OE_Ignore;
+  }
+}
+        break;
+      case 280: /* expr ::= RAISE LP raisetype COMMA expr RP */
+{
+  yymsp[-5].minor.yy590 = sqlite3PExpr(pParse, TK_RAISE, yymsp[-1].minor.yy590, 0);
+  if( yymsp[-5].minor.yy590 ) {
+    yymsp[-5].minor.yy590->affExpr = (char)yymsp[-3].minor.yy502;
+  }
+}
+        break;
+      case 281: /* raisetype ::= ROLLBACK */
+{yymsp[0].minor.yy502 = OE_Rollback;}
+        break;
+      case 283: /* raisetype ::= FAIL */
+{yymsp[0].minor.yy502 = OE_Fail;}
+        break;
+      case 284: /* cmd ::= DROP TRIGGER ifexists fullname */
+{
+  sqlite3DropTrigger(pParse,yymsp[0].minor.yy563,yymsp[-1].minor.yy502);
+}
+        break;
+      case 285: /* cmd ::= ATTACH database_kw_opt expr AS expr key_opt */
+{
+  sqlite3Attach(pParse, yymsp[-3].minor.yy590, yymsp[-1].minor.yy590, yymsp[0].minor.yy590);
+}
+        break;
+      case 286: /* cmd ::= DETACH database_kw_opt expr */
+{
+  sqlite3Detach(pParse, yymsp[0].minor.yy590);
+}
+        break;
+      case 289: /* cmd ::= REINDEX */
+{sqlite3Reindex(pParse, 0, 0);}
+        break;
+      case 290: /* cmd ::= REINDEX nm dbnm */
+{sqlite3Reindex(pParse, &yymsp[-1].minor.yy0, &yymsp[0].minor.yy0);}
+        break;
+      case 291: /* cmd ::= ANALYZE */
+{sqlite3Analyze(pParse, 0, 0);}
+        break;
+      case 292: /* cmd ::= ANALYZE nm dbnm */
+{sqlite3Analyze(pParse, &yymsp[-1].minor.yy0, &yymsp[0].minor.yy0);}
+        break;
+      case 293: /* cmd ::= ALTER TABLE fullname RENAME TO nm */
+{
+  sqlite3AlterRenameTable(pParse,yymsp[-3].minor.yy563,&yymsp[0].minor.yy0);
+}
+        break;
+      case 294: /* cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt columnname carglist */
+{
+  yymsp[-1].minor.yy0.n = (int)(pParse->sLastToken.z-yymsp[-1].minor.yy0.z) + pParse->sLastToken.n;
+  sqlite3AlterFinishAddColumn(pParse, &yymsp[-1].minor.yy0);
+}
+        break;
+      case 295: /* cmd ::= ALTER TABLE fullname DROP kwcolumn_opt nm */
+{
+  sqlite3AlterDropColumn(pParse, yymsp[-3].minor.yy563, &yymsp[0].minor.yy0);
+}
+        break;
+      case 296: /* add_column_fullname ::= fullname */
+{
+  disableLookaside(pParse);
+  sqlite3AlterBeginAddColumn(pParse, yymsp[0].minor.yy563);
+}
+        break;
+      case 297: /* cmd ::= ALTER TABLE fullname RENAME kwcolumn_opt nm TO nm */
+{
+  sqlite3AlterRenameColumn(pParse, yymsp[-5].minor.yy563, &yymsp[-2].minor.yy0, &yymsp[0].minor.yy0);
+}
+        break;
+      case 298: /* cmd ::= create_vtab */
+{sqlite3VtabFinishParse(pParse,0);}
+        break;
+      case 299: /* cmd ::= create_vtab LP vtabarglist RP */
+{sqlite3VtabFinishParse(pParse,&yymsp[0].minor.yy0);}
+        break;
+      case 300: /* create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm */
+{
+    sqlite3VtabBeginParse(pParse, &yymsp[-3].minor.yy0, &yymsp[-2].minor.yy0, &yymsp[0].minor.yy0, yymsp[-4].minor.yy502);
+}
+        break;
+      case 301: /* vtabarg ::= */
+{sqlite3VtabArgInit(pParse);}
+        break;
+      case 302: /* vtabargtoken ::= ANY */
+      case 303: /* vtabargtoken ::= lp anylist RP */ yytestcase(yyruleno==303);
+      case 304: /* lp ::= LP */ yytestcase(yyruleno==304);
+{sqlite3VtabArgExtend(pParse,&yymsp[0].minor.yy0);}
+        break;
+      case 305: /* with ::= WITH wqlist */
+      case 306: /* with ::= WITH RECURSIVE wqlist */ yytestcase(yyruleno==306);
+{ sqlite3WithPush(pParse, yymsp[0].minor.yy125, 1); }
+        break;
+      case 307: /* wqas ::= AS */
+{yymsp[0].minor.yy444 = M10d_Any;}
+        break;
+      case 308: /* wqas ::= AS MATERIALIZED */
+{yymsp[-1].minor.yy444 = M10d_Yes;}
+        break;
+      case 309: /* wqas ::= AS NOT MATERIALIZED */
+{yymsp[-2].minor.yy444 = M10d_No;}
+        break;
+      case 310: /* wqitem ::= withnm eidlist_opt wqas LP select RP */
+{
+  yymsp[-5].minor.yy361 = sqlite3CteNew(pParse, &yymsp[-5].minor.yy0, yymsp[-4].minor.yy402, yymsp[-1].minor.yy637, yymsp[-3].minor.yy444); /*A-overwrites-X*/
+}
+        break;
+      case 311: /* withnm ::= nm */
+{pParse->bHasWith = 1;}
+        break;
+      case 312: /* wqlist ::= wqitem */
+{
+  yymsp[0].minor.yy125 = sqlite3WithAdd(pParse, 0, yymsp[0].minor.yy361); /*A-overwrites-X*/
+}
+        break;
+      case 313: /* wqlist ::= wqlist COMMA wqitem */
+{
+  yymsp[-2].minor.yy125 = sqlite3WithAdd(pParse, yymsp[-2].minor.yy125, yymsp[0].minor.yy361);
+}
+        break;
+      case 314: /* windowdefn_list ::= windowdefn_list COMMA windowdefn */
+{
+  assert( yymsp[0].minor.yy483!=0 );
+  sqlite3WindowChain(pParse, yymsp[0].minor.yy483, yymsp[-2].minor.yy483);
+  yymsp[0].minor.yy483->pNextWin = yymsp[-2].minor.yy483;
+  yylhsminor.yy483 = yymsp[0].minor.yy483;
+}
+  yymsp[-2].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 315: /* windowdefn ::= nm AS LP window RP */
+{
+  if( ALWAYS(yymsp[-1].minor.yy483) ){
+    yymsp[-1].minor.yy483->zName = sqlite3DbStrNDup(pParse->db, yymsp[-4].minor.yy0.z, yymsp[-4].minor.yy0.n);
+  }
+  yylhsminor.yy483 = yymsp[-1].minor.yy483;
+}
+  yymsp[-4].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 316: /* window ::= PARTITION BY nexprlist orderby_opt frame_opt */
+{
+  yymsp[-4].minor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, yymsp[-2].minor.yy402, yymsp[-1].minor.yy402, 0);
+}
+        break;
+      case 317: /* window ::= nm PARTITION BY nexprlist orderby_opt frame_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, yymsp[-2].minor.yy402, yymsp[-1].minor.yy402, &yymsp[-5].minor.yy0);
+}
+  yymsp[-5].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 318: /* window ::= ORDER BY sortlist frame_opt */
+{
+  yymsp[-3].minor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, 0, yymsp[-1].minor.yy402, 0);
+}
+        break;
+      case 319: /* window ::= nm ORDER BY sortlist frame_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, 0, yymsp[-1].minor.yy402, &yymsp[-4].minor.yy0);
+}
+  yymsp[-4].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 320: /* window ::= nm frame_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, 0, 0, &yymsp[-1].minor.yy0);
+}
+  yymsp[-1].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 321: /* frame_opt ::= */
+{
+  yymsp[1].minor.yy483 = sqlite3WindowAlloc(pParse, 0, TK_UNBOUNDED, 0, TK_CURRENT, 0, 0);
+}
+        break;
+      case 322: /* frame_opt ::= range_or_rows frame_bound_s frame_exclude_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAlloc(pParse, yymsp[-2].minor.yy502, yymsp[-1].minor.yy205.eType, yymsp[-1].minor.yy205.pExpr, TK_CURRENT, 0, yymsp[0].minor.yy444);
+}
+  yymsp[-2].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 323: /* frame_opt ::= range_or_rows BETWEEN frame_bound_s AND frame_bound_e frame_exclude_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAlloc(pParse, yymsp[-5].minor.yy502, yymsp[-3].minor.yy205.eType, yymsp[-3].minor.yy205.pExpr, yymsp[-1].minor.yy205.eType, yymsp[-1].minor.yy205.pExpr, yymsp[0].minor.yy444);
+}
+  yymsp[-5].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 325: /* frame_bound_s ::= frame_bound */
+      case 327: /* frame_bound_e ::= frame_bound */ yytestcase(yyruleno==327);
+{yylhsminor.yy205 = yymsp[0].minor.yy205;}
+  yymsp[0].minor.yy205 = yylhsminor.yy205;
+        break;
+      case 326: /* frame_bound_s ::= UNBOUNDED PRECEDING */
+      case 328: /* frame_bound_e ::= UNBOUNDED FOLLOWING */ yytestcase(yyruleno==328);
+      case 330: /* frame_bound ::= CURRENT ROW */ yytestcase(yyruleno==330);
+{yylhsminor.yy205.eType = yymsp[-1].major; yylhsminor.yy205.pExpr = 0;}
+  yymsp[-1].minor.yy205 = yylhsminor.yy205;
+        break;
+      case 329: /* frame_bound ::= expr PRECEDING|FOLLOWING */
+{yylhsminor.yy205.eType = yymsp[0].major; yylhsminor.yy205.pExpr = yymsp[-1].minor.yy590;}
+  yymsp[-1].minor.yy205 = yylhsminor.yy205;
+        break;
+      case 331: /* frame_exclude_opt ::= */
+{yymsp[1].minor.yy444 = 0;}
+        break;
+      case 332: /* frame_exclude_opt ::= EXCLUDE frame_exclude */
+{yymsp[-1].minor.yy444 = yymsp[0].minor.yy444;}
+        break;
+      case 333: /* frame_exclude ::= NO OTHERS */
+      case 334: /* frame_exclude ::= CURRENT ROW */ yytestcase(yyruleno==334);
+{yymsp[-1].minor.yy444 = yymsp[-1].major; /*A-overwrites-X*/}
+        break;
+      case 335: /* frame_exclude ::= GROUP|TIES */
+{yymsp[0].minor.yy444 = yymsp[0].major; /*A-overwrites-X*/}
+        break;
+      case 336: /* window_clause ::= WINDOW windowdefn_list */
+{ yymsp[-1].minor.yy483 = yymsp[0].minor.yy483; }
+        break;
+      case 337: /* filter_over ::= filter_clause over_clause */
+{
+  if( yymsp[0].minor.yy483 ){
+    yymsp[0].minor.yy483->pFilter = yymsp[-1].minor.yy590;
+  }else{
+    sqlite3ExprDelete(pParse->db, yymsp[-1].minor.yy590);
+  }
+  yylhsminor.yy483 = yymsp[0].minor.yy483;
+}
+  yymsp[-1].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 338: /* filter_over ::= over_clause */
+{
+  yylhsminor.yy483 = yymsp[0].minor.yy483;
+}
+  yymsp[0].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 339: /* filter_over ::= filter_clause */
+{
+  yylhsminor.yy483 = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
+  if( yylhsminor.yy483 ){
+    yylhsminor.yy483->eFrmType = TK_FILTER;
+    yylhsminor.yy483->pFilter = yymsp[0].minor.yy590;
+  }else{
+    sqlite3ExprDelete(pParse->db, yymsp[0].minor.yy590);
+  }
+}
+  yymsp[0].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 340: /* over_clause ::= OVER LP window RP */
+{
+  yymsp[-3].minor.yy483 = yymsp[-1].minor.yy483;
+  assert( yymsp[-3].minor.yy483!=0 );
+}
+        break;
+      case 341: /* over_clause ::= OVER nm */
+{
+  yymsp[-1].minor.yy483 = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
+  if( yymsp[-1].minor.yy483 ){
+    yymsp[-1].minor.yy483->zName = sqlite3DbStrNDup(pParse->db, yymsp[0].minor.yy0.z, yymsp[0].minor.yy0.n);
+  }
+}
+        break;
+      case 342: /* filter_clause ::= FILTER LP WHERE expr RP */
+{ yymsp[-4].minor.yy590 = yymsp[-1].minor.yy590; }
+        break;
+      case 343: /* term ::= QNUMBER */
+{
+  yylhsminor.yy590=tokenExpr(pParse,yymsp[0].major,yymsp[0].minor.yy0);
+  sqlite3DequoteNumber(pParse, yylhsminor.yy590);
+}
+  yymsp[0].minor.yy590 = yylhsminor.yy590;
+        break;
+      default:
+      /* (344) input ::= cmdlist */ yytestcase(yyruleno==344);
+      /* (345) cmdlist ::= cmdlist ecmd */ yytestcase(yyruleno==345);
+      /* (346) cmdlist ::= ecmd (OPTIMIZED OUT) */ assert(yyruleno!=346);
+      /* (347) ecmd ::= SEMI */ yytestcase(yyruleno==347);
+      /* (348) ecmd ::= cmdx SEMI */ yytestcase(yyruleno==348);
+      /* (349) ecmd ::= explain cmdx SEMI (NEVER REDUCES) */ assert(yyruleno!=349);
+      /* (350) trans_opt ::= */ yytestcase(yyruleno==350);
+      /* (351) trans_opt ::= TRANSACTION */ yytestcase(yyruleno==351);
+      /* (352) trans_opt ::= TRANSACTION nm */ yytestcase(yyruleno==352);
+      /* (353) savepoint_opt ::= SAVEPOINT */ yytestcase(yyruleno==353);
+      /* (354) savepoint_opt ::= */ yytestcase(yyruleno==354);
+      /* (355) cmd ::= create_table create_table_args */ yytestcase(yyruleno==355);
+      /* (356) table_option_set ::= table_option (OPTIMIZED OUT) */ assert(yyruleno!=356);
+      /* (357) columnlist ::= columnlist COMMA columnname carglist */ yytestcase(yyruleno==357);
+      /* (358) columnlist ::= columnname carglist */ yytestcase(yyruleno==358);
+      /* (359) nm ::= ID|INDEXED|JOIN_KW */ yytestcase(yyruleno==359);
+      /* (360) nm ::= STRING */ yytestcase(yyruleno==360);
+      /* (361) typetoken ::= typename */ yytestcase(yyruleno==361);
+      /* (362) typename ::= ID|STRING */ yytestcase(yyruleno==362);
+      /* (363) signed ::= plus_num (OPTIMIZED OUT) */ assert(yyruleno!=363);
+      /* (364) signed ::= minus_num (OPTIMIZED OUT) */ assert(yyruleno!=364);
+      /* (365) carglist ::= carglist ccons */ yytestcase(yyruleno==365);
+      /* (366) carglist ::= */ yytestcase(yyruleno==366);
+      /* (367) ccons ::= NULL onconf */ yytestcase(yyruleno==367);
+      /* (368) ccons ::= GENERATED ALWAYS AS generated */ yytestcase(yyruleno==368);
+      /* (369) ccons ::= AS generated */ yytestcase(yyruleno==369);
+      /* (370) conslist_opt ::= COMMA conslist */ yytestcase(yyruleno==370);
+      /* (371) conslist ::= conslist tconscomma tcons */ yytestcase(yyruleno==371);
+      /* (372) conslist ::= tcons (OPTIMIZED OUT) */ assert(yyruleno!=372);
+      /* (373) tconscomma ::= */ yytestcase(yyruleno==373);
+      /* (374) defer_subclause_opt ::= defer_subclause (OPTIMIZED OUT) */ assert(yyruleno!=374);
+      /* (375) resolvetype ::= raisetype (OPTIMIZED OUT) */ assert(yyruleno!=375);
+      /* (376) selectnowith ::= oneselect (OPTIMIZED OUT) */ assert(yyruleno!=376);
+      /* (377) oneselect ::= values */ yytestcase(yyruleno==377);
+      /* (378) sclp ::= selcollist COMMA */ yytestcase(yyruleno==378);
+      /* (379) as ::= ID|STRING */ yytestcase(yyruleno==379);
+      /* (380) indexed_opt ::= indexed_by (OPTIMIZED OUT) */ assert(yyruleno!=380);
+      /* (381) returning ::= */ yytestcase(yyruleno==381);
+      /* (382) expr ::= term (OPTIMIZED OUT) */ assert(yyruleno!=382);
+      /* (383) likeop ::= LIKE_KW|MATCH */ yytestcase(yyruleno==383);
+      /* (384) case_operand ::= expr */ yytestcase(yyruleno==384);
+      /* (385) exprlist ::= nexprlist */ yytestcase(yyruleno==385);
+      /* (386) nmnum ::= plus_num (OPTIMIZED OUT) */ assert(yyruleno!=386);
+      /* (387) nmnum ::= nm (OPTIMIZED OUT) */ assert(yyruleno!=387);
+      /* (388) nmnum ::= ON */ yytestcase(yyruleno==388);
+      /* (389) nmnum ::= DELETE */ yytestcase(yyruleno==389);
+      /* (390) nmnum ::= DEFAULT */ yytestcase(yyruleno==390);
+      /* (391) plus_num ::= INTEGER|FLOAT */ yytestcase(yyruleno==391);
+      /* (392) foreach_clause ::= */ yytestcase(yyruleno==392);
+      /* (393) foreach_clause ::= FOR EACH ROW */ yytestcase(yyruleno==393);
+      /* (394) trnm ::= nm */ yytestcase(yyruleno==394);
+      /* (395) tridxby ::= */ yytestcase(yyruleno==395);
+      /* (396) database_kw_opt ::= DATABASE */ yytestcase(yyruleno==396);
+      /* (397) database_kw_opt ::= */ yytestcase(yyruleno==397);
+      /* (398) kwcolumn_opt ::= */ yytestcase(yyruleno==398);
+      /* (399) kwcolumn_opt ::= COLUMNKW */ yytestcase(yyruleno==399);
+      /* (400) vtabarglist ::= vtabarg */ yytestcase(yyruleno==400);
+      /* (401) vtabarglist ::= vtabarglist COMMA vtabarg */ yytestcase(yyruleno==401);
+      /* (402) vtabarg ::= vtabarg vtabargtoken */ yytestcase(yyruleno==402);
+      /* (403) anylist ::= */ yytestcase(yyruleno==403);
+      /* (404) anylist ::= anylist LP anylist RP */ yytestcase(yyruleno==404);
+      /* (405) anylist ::= anylist ANY */ yytestcase(yyruleno==405);
+      /* (406) with ::= */ yytestcase(yyruleno==406);
+      /* (407) windowdefn_list ::= windowdefn (OPTIMIZED OUT) */ assert(yyruleno!=407);
+      /* (408) window ::= frame_opt (OPTIMIZED OUT) */ assert(yyruleno!=408);
+        break;
+/********** End reduce actions ************************************************/
+  };
+  assert( yyruleno<sizeof(yyRuleInfoLhs)/sizeof(yyRuleInfoLhs[0]) );
+  yygoto = yyRuleInfoLhs[yyruleno];
+  yysize = yyRuleInfoNRhs[yyruleno];
+  yyact = yy_find_reduce_action(yymsp[yysize].stateno,(YYCODETYPE)yygoto);
+
+  /* There are no SHIFTREDUCE actions on nonterminals because the table
+  ** generator has simplified them to pure REDUCE actions. */
+  assert( !(yyact>YY_MAX_SHIFT && yyact<=YY_MAX_SHIFTREDUCE) );
+
+  /* It is not possible for a REDUCE to be followed by an error */
+  assert( yyact!=YY_ERROR_ACTION );
+
+  yymsp += yysize+1;
+  yypParser->yytos = yymsp;
+  yymsp->stateno = (YYACTIONTYPE)yyact;
+  yymsp->major = (YYCODETYPE)yygoto;
+  yyTraceShift(yypParser, yyact, "... then shift");
+  return yyact;
+}
+
+/*
+** The following code executes when the parse fails
+*/
+#ifndef YYNOERRORRECOVERY
+static void yy_parse_failed(
+  yyParser *yypParser           /* The parser */
+){
+  sqlite3ParserARG_FETCH
+  sqlite3ParserCTX_FETCH
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sFail!\n",yyTracePrompt);
+  }
+#endif
+  while( yypParser->yytos>yypParser->yystack ) yy_pop_parser_stack(yypParser);
+  /* Here code is inserted which will be executed whenever the
+  ** parser fails */
+/************ Begin %parse_failure code ***************************************/
+/************ End %parse_failure code *****************************************/
+  sqlite3ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3ParserCTX_STORE
+}
+#endif /* YYNOERRORRECOVERY */
+
+/*
+** The following code executes when a syntax error first occurs.
+*/
+static void yy_syntax_error(
+  yyParser *yypParser,           /* The parser */
+  int yymajor,                   /* The major type of the error token */
+  sqlite3ParserTOKENTYPE yyminor         /* The minor type of the error token */
+){
+  sqlite3ParserARG_FETCH
+  sqlite3ParserCTX_FETCH
+#define TOKEN yyminor
+/************ Begin %syntax_error code ****************************************/
+
+  UNUSED_PARAMETER(yymajor);  /* Silence some compiler warnings */
+  if( TOKEN.z[0] ){
+    parserSyntaxError(pParse, &TOKEN);
+  }else{
+    sqlite3ErrorMsg(pParse, "incomplete input");
+  }
+/************ End %syntax_error code ******************************************/
+  sqlite3ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3ParserCTX_STORE
+}
+
+/*
+** The following is executed when the parser accepts
+*/
+static void yy_accept(
+  yyParser *yypParser           /* The parser */
+){
+  sqlite3ParserARG_FETCH
+  sqlite3ParserCTX_FETCH
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sAccept!\n",yyTracePrompt);
+  }
+#endif
+#ifndef YYNOERRORRECOVERY
+  yypParser->yyerrcnt = -1;
+#endif
+  assert( yypParser->yytos==yypParser->yystack );
+  /* Here code is inserted which will be executed whenever the
+  ** parser accepts */
+/*********** Begin %parse_accept code *****************************************/
+/*********** End %parse_accept code *******************************************/
+  sqlite3ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3ParserCTX_STORE
+}
+
+/* The main parser program.
+** The first argument is a pointer to a structure obtained from
+** "sqlite3ParserAlloc" which describes the current state of the parser.
+** The second argument is the major token number.  The third is
+** the minor token.  The fourth optional argument is whatever the
+** user wants (and specified in the grammar) and is available for
+** use by the action routines.
+**
+** Inputs:
+** <ul>
+** <li> A pointer to the parser (an opaque structure.)
+** <li> The major token number.
+** <li> The minor token number.
+** <li> An option argument of a grammar-specified type.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+SQLITE_PRIVATE void sqlite3Parser(
+  void *yyp,                   /* The parser */
+  int yymajor,                 /* The major token code number */
+  sqlite3ParserTOKENTYPE yyminor       /* The value for the token */
+  sqlite3ParserARG_PDECL               /* Optional %extra_argument parameter */
+){
+  YYMINORTYPE yyminorunion;
+  YYACTIONTYPE yyact;   /* The parser action. */
+#if !defined(YYERRORSYMBOL) && !defined(YYNOERRORRECOVERY)
+  int yyendofinput;     /* True if we are at the end of input */
+#endif
+#ifdef YYERRORSYMBOL
+  int yyerrorhit = 0;   /* True if yymajor has invoked an error */
+#endif
+  yyParser *yypParser = (yyParser*)yyp;  /* The parser */
+  sqlite3ParserCTX_FETCH
+  sqlite3ParserARG_STORE
+
+  assert( yypParser->yytos!=0 );
+#if !defined(YYERRORSYMBOL) && !defined(YYNOERRORRECOVERY)
+  yyendofinput = (yymajor==0);
+#endif
+
+  yyact = yypParser->yytos->stateno;
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    if( yyact < YY_MIN_REDUCE ){
+      fprintf(yyTraceFILE,"%sInput '%s' in state %d\n",
+              yyTracePrompt,yyTokenName[yymajor],yyact);
+    }else{
+      fprintf(yyTraceFILE,"%sInput '%s' with pending reduce %d\n",
+              yyTracePrompt,yyTokenName[yymajor],yyact-YY_MIN_REDUCE);
+    }
+  }
+#endif
+
+  while(1){ /* Exit by "break" */
+    assert( yypParser->yytos>=yypParser->yystack );
+    assert( yyact==yypParser->yytos->stateno );
+    yyact = yy_find_shift_action((YYCODETYPE)yymajor,yyact);
+    if( yyact >= YY_MIN_REDUCE ){
+      unsigned int yyruleno = yyact - YY_MIN_REDUCE; /* Reduce by this rule */
+#ifndef NDEBUG
+      assert( yyruleno<(int)(sizeof(yyRuleName)/sizeof(yyRuleName[0])) );
+      if( yyTraceFILE ){
+        int yysize = yyRuleInfoNRhs[yyruleno];
+        if( yysize ){
+          fprintf(yyTraceFILE, "%sReduce %d [%s]%s, pop back to state %d.\n",
+            yyTracePrompt,
+            yyruleno, yyRuleName[yyruleno],
+            yyruleno<YYNRULE_WITH_ACTION ? "" : " without external action",
+            yypParser->yytos[yysize].stateno);
+        }else{
+          fprintf(yyTraceFILE, "%sReduce %d [%s]%s.\n",
+            yyTracePrompt, yyruleno, yyRuleName[yyruleno],
+            yyruleno<YYNRULE_WITH_ACTION ? "" : " without external action");
+        }
+      }
+#endif /* NDEBUG */
+
+      /* Check that the stack is large enough to grow by a single entry
+      ** if the RHS of the rule is empty.  This ensures that there is room
+      ** enough on the stack to push the LHS value */
+      if( yyRuleInfoNRhs[yyruleno]==0 ){
+#ifdef YYTRACKMAXSTACKDEPTH
+        if( (int)(yypParser->yytos - yypParser->yystack)>yypParser->yyhwm ){
+          yypParser->yyhwm++;
+          assert( yypParser->yyhwm ==
+                  (int)(yypParser->yytos - yypParser->yystack));
+        }
+#endif
+        if( yypParser->yytos>=yypParser->yystackEnd ){
+          if( yyGrowStack(yypParser) ){
+            yyStackOverflow(yypParser);
+            break;
+          }
+        }
+      }
+      yyact = yy_reduce(yypParser,yyruleno,yymajor,yyminor sqlite3ParserCTX_PARAM);
+    }else if( yyact <= YY_MAX_SHIFTREDUCE ){
+      yy_shift(yypParser,yyact,(YYCODETYPE)yymajor,yyminor);
+#ifndef YYNOERRORRECOVERY
+      yypParser->yyerrcnt--;
+#endif
+      break;
+    }else if( yyact==YY_ACCEPT_ACTION ){
+      yypParser->yytos--;
+      yy_accept(yypParser);
+      return;
+    }else{
+      assert( yyact == YY_ERROR_ACTION );
+      yyminorunion.yy0 = yyminor;
+#ifdef YYERRORSYMBOL
+      int yymx;
+#endif
+#ifndef NDEBUG
+      if( yyTraceFILE ){
+        fprintf(yyTraceFILE,"%sSyntax Error!\n",yyTracePrompt);
+      }
+#endif
+#ifdef YYERRORSYMBOL
+      /* A syntax error has occurred.
+      ** The response to an error depends upon whether or not the
+      ** grammar defines an error token "ERROR".
+      **
+      ** This is what we do if the grammar does define ERROR:
+      **
+      **  * Call the %syntax_error function.
+      **
+      **  * Begin popping the stack until we enter a state where
+      **    it is legal to shift the error symbol, then shift
+      **    the error symbol.
+      **
+      **  * Set the error count to three.
+      **
+      **  * Begin accepting and shifting new tokens.  No new error
+      **    processing will occur until three tokens have been
+      **    shifted successfully.
+      **
+      */
+      if( yypParser->yyerrcnt<0 ){
+        yy_syntax_error(yypParser,yymajor,yyminor);
+      }
+      yymx = yypParser->yytos->major;
+      if( yymx==YYERRORSYMBOL || yyerrorhit ){
+#ifndef NDEBUG
+        if( yyTraceFILE ){
+          fprintf(yyTraceFILE,"%sDiscard input token %s\n",
+             yyTracePrompt,yyTokenName[yymajor]);
+        }
+#endif
+        yy_destructor(yypParser, (YYCODETYPE)yymajor, &yyminorunion);
+        yymajor = YYNOCODE;
+      }else{
+        while( yypParser->yytos > yypParser->yystack ){
+          yyact = yy_find_reduce_action(yypParser->yytos->stateno,
+                                        YYERRORSYMBOL);
+          if( yyact<=YY_MAX_SHIFTREDUCE ) break;
+          yy_pop_parser_stack(yypParser);
+        }
+        if( yypParser->yytos <= yypParser->yystack || yymajor==0 ){
+          yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+          yy_parse_failed(yypParser);
+#ifndef YYNOERRORRECOVERY
+          yypParser->yyerrcnt = -1;
+#endif
+          yymajor = YYNOCODE;
+        }else if( yymx!=YYERRORSYMBOL ){
+          yy_shift(yypParser,yyact,YYERRORSYMBOL,yyminor);
+        }
+      }
+      yypParser->yyerrcnt = 3;
+      yyerrorhit = 1;
+      if( yymajor==YYNOCODE ) break;
+      yyact = yypParser->yytos->stateno;
+#elif defined(YYNOERRORRECOVERY)
+      /* If the YYNOERRORRECOVERY macro is defined, then do not attempt to
+      ** do any kind of error recovery.  Instead, simply invoke the syntax
+      ** error routine and continue going as if nothing had happened.
+      **
+      ** Applications can set this macro (for example inside %include) if
+      ** they intend to abandon the parse upon the first syntax error seen.
+      */
+      yy_syntax_error(yypParser,yymajor, yyminor);
+      yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+      break;
+#else  /* YYERRORSYMBOL is not defined */
+      /* This is what we do if the grammar does not define ERROR:
+      **
+      **  * Report an error message, and throw away the input token.
+      **
+      **  * If the input token is $, then fail the parse.
+      **
+      ** As before, subsequent error messages are suppressed until
+      ** three input tokens have been successfully shifted.
+      */
+      if( yypParser->yyerrcnt<=0 ){
+        yy_syntax_error(yypParser,yymajor, yyminor);
+      }
+      yypParser->yyerrcnt = 3;
+      yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+      if( yyendofinput ){
+        yy_parse_failed(yypParser);
+#ifndef YYNOERRORRECOVERY
+        yypParser->yyerrcnt = -1;
+#endif
+      }
+      break;
+#endif
+    }
+  }
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    yyStackEntry *i;
+    char cDiv = '[';
+    fprintf(yyTraceFILE,"%sReturn. Stack=",yyTracePrompt);
+    for(i=&yypParser->yystack[1]; i<=yypParser->yytos; i++){
+      fprintf(yyTraceFILE,"%c%s", cDiv, yyTokenName[i->major]);
+      cDiv = ' ';
+    }
+    fprintf(yyTraceFILE,"]\n");
+  }
+#endif
+  return;
+}
+
+/*
+** Return the fallback token corresponding to canonical token iToken, or
+** 0 if iToken has no fallback.
+*/
+SQLITE_PRIVATE int sqlite3ParserFallback(int iToken){
+#ifdef YYFALLBACK
+  assert( iToken<(int)(sizeof(yyFallback)/sizeof(yyFallback[0])) );
+  return yyFallback[iToken];
+#else
+  (void)iToken;
+  return 0;
+#endif
+}
+
+/************** End of parse.c ***********************************************/
+/************** Begin file tokenize.c ****************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** An tokenizer for SQL
+**
+** This file contains C code that splits an SQL input string up into
+** individual tokens and sends those tokens one-by-one over to the
+** parser for analysis.
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdlib.h> */
+
+/* Character classes for tokenizing
+**
+** In the sqlite3GetToken() function, a switch() on aiClass[c] is implemented
+** using a lookup table, whereas a switch() directly on c uses a binary search.
+** The lookup table is much faster.  To maximize speed, and to ensure that
+** a lookup table is used, all of the classes need to be small integers and
+** all of them need to be used within the switch.
+*/
+#define CC_X          0    /* The letter 'x', or start of BLOB literal */
+#define CC_KYWD0      1    /* First letter of a keyword */
+#define CC_KYWD       2    /* Alphabetics or '_'.  Usable in a keyword */
+#define CC_DIGIT      3    /* Digits */
+#define CC_DOLLAR     4    /* '$' */
+#define CC_VARALPHA   5    /* '@', '#', ':'.  Alphabetic SQL variables */
+#define CC_VARNUM     6    /* '?'.  Numeric SQL variables */
+#define CC_SPACE      7    /* Space characters */
+#define CC_QUOTE      8    /* '"', '\'', or '`'.  String literals, quoted ids */
+#define CC_QUOTE2     9    /* '['.   [...] style quoted ids */
+#define CC_PIPE      10    /* '|'.   Bitwise OR or concatenate */
+#define CC_MINUS     11    /* '-'.  Minus or SQL-style comment */
+#define CC_LT        12    /* '<'.  Part of < or <= or <> */
+#define CC_GT        13    /* '>'.  Part of > or >= */
+#define CC_EQ        14    /* '='.  Part of = or == */
+#define CC_BANG      15    /* '!'.  Part of != */
+#define CC_SLASH     16    /* '/'.  / or c-style comment */
+#define CC_LP        17    /* '(' */
+#define CC_RP        18    /* ')' */
+#define CC_SEMI      19    /* ';' */
+#define CC_PLUS      20    /* '+' */
+#define CC_STAR      21    /* '*' */
+#define CC_PERCENT   22    /* '%' */
+#define CC_COMMA     23    /* ',' */
+#define CC_AND       24    /* '&' */
+#define CC_TILDA     25    /* '~' */
+#define CC_DOT       26    /* '.' */
+#define CC_ID        27    /* unicode characters usable in IDs */
+#define CC_ILLEGAL   28    /* Illegal character */
+#define CC_NUL       29    /* 0x00 */
+#define CC_BOM       30    /* First byte of UTF8 BOM:  0xEF 0xBB 0xBF */
+
+static const unsigned char aiClass[] = {
+#ifdef SQLITE_ASCII
+/*         x0  x1  x2  x3  x4  x5  x6  x7  x8  x9  xa  xb  xc  xd  xe  xf */
+/* 0x */   29, 28, 28, 28, 28, 28, 28, 28, 28,  7,  7, 28,  7,  7, 28, 28,
+/* 1x */   28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+/* 2x */    7, 15,  8,  5,  4, 22, 24,  8, 17, 18, 21, 20, 23, 11, 26, 16,
+/* 3x */    3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  5, 19, 12, 14, 13,  6,
+/* 4x */    5,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+/* 5x */    1,  1,  1,  1,  1,  1,  1,  1,  0,  2,  2,  9, 28, 28, 28,  2,
+/* 6x */    8,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+/* 7x */    1,  1,  1,  1,  1,  1,  1,  1,  0,  2,  2, 28, 10, 28, 25, 28,
+/* 8x */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* 9x */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Ax */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Bx */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Cx */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Dx */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Ex */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 30,
+/* Fx */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27
+#endif
+#ifdef SQLITE_EBCDIC
+/*         x0  x1  x2  x3  x4  x5  x6  x7  x8  x9  xa  xb  xc  xd  xe  xf */
+/* 0x */   29, 28, 28, 28, 28,  7, 28, 28, 28, 28, 28, 28,  7,  7, 28, 28,
+/* 1x */   28, 28, 28, 28, 28,  7, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+/* 2x */   28, 28, 28, 28, 28,  7, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+/* 3x */   28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+/* 4x */    7, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 26, 12, 17, 20, 10,
+/* 5x */   24, 28, 28, 28, 28, 28, 28, 28, 28, 28, 15,  4, 21, 18, 19, 28,
+/* 6x */   11, 16, 28, 28, 28, 28, 28, 28, 28, 28, 28, 23, 22,  2, 13,  6,
+/* 7x */   28, 28, 28, 28, 28, 28, 28, 28, 28,  8,  5,  5,  5,  8, 14,  8,
+/* 8x */   28,  1,  1,  1,  1,  1,  1,  1,  1,  1, 28, 28, 28, 28, 28, 28,
+/* 9x */   28,  1,  1,  1,  1,  1,  1,  1,  1,  1, 28, 28, 28, 28, 28, 28,
+/* Ax */   28, 25,  1,  1,  1,  1,  1,  0,  2,  2, 28, 28, 28, 28, 28, 28,
+/* Bx */   28, 28, 28, 28, 28, 28, 28, 28, 28, 28,  9, 28, 28, 28, 28, 28,
+/* Cx */   28,  1,  1,  1,  1,  1,  1,  1,  1,  1, 28, 28, 28, 28, 28, 28,
+/* Dx */   28,  1,  1,  1,  1,  1,  1,  1,  1,  1, 28, 28, 28, 28, 28, 28,
+/* Ex */   28, 28,  1,  1,  1,  1,  1,  0,  2,  2, 28, 28, 28, 28, 28, 28,
+/* Fx */    3,  3,  3,  3,  3,  3,  3,  3,  3,  3, 28, 28, 28, 28, 28, 28,
+#endif
+};
+
+/*
+** The charMap() macro maps alphabetic characters (only) into their
+** lower-case ASCII equivalent.  On ASCII machines, this is just
+** an upper-to-lower case map.  On EBCDIC machines we also need
+** to adjust the encoding.  The mapping is only valid for alphabetics
+** which are the only characters for which this feature is used.
+**
+** Used by keywordhash.h
+*/
+#ifdef SQLITE_ASCII
+# define charMap(X) sqlite3UpperToLower[(unsigned char)X]
+#endif
+#ifdef SQLITE_EBCDIC
+# define charMap(X) ebcdicToAscii[(unsigned char)X]
+const unsigned char ebcdicToAscii[] = {
+/* 0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 0x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 1x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 2x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 3x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 4x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 5x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 95,  0,  0,  /* 6x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 7x */
+   0, 97, 98, 99,100,101,102,103,104,105,  0,  0,  0,  0,  0,  0,  /* 8x */
+   0,106,107,108,109,110,111,112,113,114,  0,  0,  0,  0,  0,  0,  /* 9x */
+   0,  0,115,116,117,118,119,120,121,122,  0,  0,  0,  0,  0,  0,  /* Ax */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* Bx */
+   0, 97, 98, 99,100,101,102,103,104,105,  0,  0,  0,  0,  0,  0,  /* Cx */
+   0,106,107,108,109,110,111,112,113,114,  0,  0,  0,  0,  0,  0,  /* Dx */
+   0,  0,115,116,117,118,119,120,121,122,  0,  0,  0,  0,  0,  0,  /* Ex */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* Fx */
+};
+#endif
+
+/*
+** The sqlite3KeywordCode function looks up an identifier to determine if
+** it is a keyword.  If it is a keyword, the token code of that keyword is
+** returned.  If the input is not a keyword, TK_ID is returned.
+**
+** The implementation of this routine was generated by a program,
+** mkkeywordhash.c, located in the tool subdirectory of the distribution.
+** The output of the mkkeywordhash.c program is written into a file
+** named keywordhash.h and then included into this source file by
+** the #include below.
+*/
+/************** Include keywordhash.h in the middle of tokenize.c ************/
+/************** Begin file keywordhash.h *************************************/
+/***** This file contains automatically generated code ******
+**
+** The code in this file has been automatically generated by
+**
+**   sqlite/tool/mkkeywordhash.c
+**
+** The code in this file implements a function that determines whether
+** or not a given identifier is really an SQL keyword.  The same thing
+** might be implemented more directly using a hand-written hash table.
+** But by using this automatically generated code, the size of the code
+** is substantially reduced.  This is important for embedded applications
+** on platforms with limited memory.
+*/
+/* Hash score: 231 */
+/* zKWText[] encodes 1007 bytes of keyword text in 667 bytes */
+/*   REINDEXEDESCAPEACHECKEYBEFOREIGNOREGEXPLAINSTEADDATABASELECT       */
+/*   ABLEFTHENDEFERRABLELSEXCLUDELETEMPORARYISNULLSAVEPOINTERSECT       */
+/*   IESNOTNULLIKEXCEPTRANSACTIONATURALTERAISEXCLUSIVEXISTS             */
+/*   CONSTRAINTOFFSETRIGGERANGENERATEDETACHAVINGLOBEGINNEREFERENCES     */
+/*   UNIQUERYWITHOUTERELEASEATTACHBETWEENOTHINGROUPSCASCADEFAULT        */
+/*   CASECOLLATECREATECURRENT_DATEIMMEDIATEJOINSERTMATCHPLANALYZE       */
+/*   PRAGMATERIALIZEDEFERREDISTINCTUPDATEVALUESVIRTUALWAYSWHENWHERE     */
+/*   CURSIVEABORTAFTERENAMEANDROPARTITIONAUTOINCREMENTCASTCOLUMN        */
+/*   COMMITCONFLICTCROSSCURRENT_TIMESTAMPRECEDINGFAILASTFILTER          */
+/*   EPLACEFIRSTFOLLOWINGFROMFULLIMITIFORDERESTRICTOTHERSOVER           */
+/*   ETURNINGRIGHTROLLBACKROWSUNBOUNDEDUNIONUSINGVACUUMVIEWINDOWBY      */
+/*   INITIALLYPRIMARY                                                   */
+static const char zKWText[666] = {
+  'R','E','I','N','D','E','X','E','D','E','S','C','A','P','E','A','C','H',
+  'E','C','K','E','Y','B','E','F','O','R','E','I','G','N','O','R','E','G',
+  'E','X','P','L','A','I','N','S','T','E','A','D','D','A','T','A','B','A',
+  'S','E','L','E','C','T','A','B','L','E','F','T','H','E','N','D','E','F',
+  'E','R','R','A','B','L','E','L','S','E','X','C','L','U','D','E','L','E',
+  'T','E','M','P','O','R','A','R','Y','I','S','N','U','L','L','S','A','V',
+  'E','P','O','I','N','T','E','R','S','E','C','T','I','E','S','N','O','T',
+  'N','U','L','L','I','K','E','X','C','E','P','T','R','A','N','S','A','C',
+  'T','I','O','N','A','T','U','R','A','L','T','E','R','A','I','S','E','X',
+  'C','L','U','S','I','V','E','X','I','S','T','S','C','O','N','S','T','R',
+  'A','I','N','T','O','F','F','S','E','T','R','I','G','G','E','R','A','N',
+  'G','E','N','E','R','A','T','E','D','E','T','A','C','H','A','V','I','N',
+  'G','L','O','B','E','G','I','N','N','E','R','E','F','E','R','E','N','C',
+  'E','S','U','N','I','Q','U','E','R','Y','W','I','T','H','O','U','T','E',
+  'R','E','L','E','A','S','E','A','T','T','A','C','H','B','E','T','W','E',
+  'E','N','O','T','H','I','N','G','R','O','U','P','S','C','A','S','C','A',
+  'D','E','F','A','U','L','T','C','A','S','E','C','O','L','L','A','T','E',
+  'C','R','E','A','T','E','C','U','R','R','E','N','T','_','D','A','T','E',
+  'I','M','M','E','D','I','A','T','E','J','O','I','N','S','E','R','T','M',
+  'A','T','C','H','P','L','A','N','A','L','Y','Z','E','P','R','A','G','M',
+  'A','T','E','R','I','A','L','I','Z','E','D','E','F','E','R','R','E','D',
+  'I','S','T','I','N','C','T','U','P','D','A','T','E','V','A','L','U','E',
+  'S','V','I','R','T','U','A','L','W','A','Y','S','W','H','E','N','W','H',
+  'E','R','E','C','U','R','S','I','V','E','A','B','O','R','T','A','F','T',
+  'E','R','E','N','A','M','E','A','N','D','R','O','P','A','R','T','I','T',
+  'I','O','N','A','U','T','O','I','N','C','R','E','M','E','N','T','C','A',
+  'S','T','C','O','L','U','M','N','C','O','M','M','I','T','C','O','N','F',
+  'L','I','C','T','C','R','O','S','S','C','U','R','R','E','N','T','_','T',
+  'I','M','E','S','T','A','M','P','R','E','C','E','D','I','N','G','F','A',
+  'I','L','A','S','T','F','I','L','T','E','R','E','P','L','A','C','E','F',
+  'I','R','S','T','F','O','L','L','O','W','I','N','G','F','R','O','M','F',
+  'U','L','L','I','M','I','T','I','F','O','R','D','E','R','E','S','T','R',
+  'I','C','T','O','T','H','E','R','S','O','V','E','R','E','T','U','R','N',
+  'I','N','G','R','I','G','H','T','R','O','L','L','B','A','C','K','R','O',
+  'W','S','U','N','B','O','U','N','D','E','D','U','N','I','O','N','U','S',
+  'I','N','G','V','A','C','U','U','M','V','I','E','W','I','N','D','O','W',
+  'B','Y','I','N','I','T','I','A','L','L','Y','P','R','I','M','A','R','Y',
+};
+/* aKWHash[i] is the hash value for the i-th keyword */
+static const unsigned char aKWHash[127] = {
+    84,  92, 134,  82, 105,  29,   0,   0,  94,   0,  85,  72,   0,
+    53,  35,  86,  15,   0,  42,  97,  54,  89, 135,  19,   0,   0,
+   140,   0,  40, 129,   0,  22, 107,   0,   9,   0,   0, 123,  80,
+     0,  78,   6,   0,  65, 103, 147,   0, 136, 115,   0,   0,  48,
+     0,  90,  24,   0,  17,   0,  27,  70,  23,  26,   5,  60, 142,
+   110, 122,   0,  73,  91,  71, 145,  61, 120,  74,   0,  49,   0,
+    11,  41,   0, 113,   0,   0,   0, 109,  10, 111, 116, 125,  14,
+    50, 124,   0, 100,   0,  18, 121, 144,  56, 130, 139,  88,  83,
+    37,  30, 126,   0,   0, 108,  51, 131, 128,   0,  34,   0,   0,
+   132,   0,  98,  38,  39,   0,  20,  45, 117,  93,
+};
+/* aKWNext[] forms the hash collision chain.  If aKWHash[i]==0
+** then the i-th keyword has no more hash collisions.  Otherwise,
+** the next keyword with the same hash is aKWHash[i]-1. */
+static const unsigned char aKWNext[148] = {0,
+     0,   0,   0,   0,   4,   0,  43,   0,   0, 106, 114,   0,   0,
+     0,   2,   0,   0, 143,   0,   0,   0,  13,   0,   0,   0,   0,
+   141,   0,   0, 119,  52,   0,   0, 137,  12,   0,   0,  62,   0,
+   138,   0, 133,   0,   0,  36,   0,   0,  28,  77,   0,   0,   0,
+     0,  59,   0,  47,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+     0,  69,   0,   0,   0,   0,   0, 146,   3,   0,  58,   0,   1,
+    75,   0,   0,   0,  31,   0,   0,   0,   0,   0, 127,   0, 104,
+     0,  64,  66,  63,   0,   0,   0,   0,   0,  46,   0,  16,   8,
+     0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  81, 101,   0,
+   112,  21,   7,  67,   0,  79,  96, 118,   0,   0,  68,   0,   0,
+    99,  44,   0,  55,   0,  76,   0,  95,  32,  33,  57,  25,   0,
+   102,   0,   0,  87,
+};
+/* aKWLen[i] is the length (in bytes) of the i-th keyword */
+static const unsigned char aKWLen[148] = {0,
+     7,   7,   5,   4,   6,   4,   5,   3,   6,   7,   3,   6,   6,
+     7,   7,   3,   8,   2,   6,   5,   4,   4,   3,  10,   4,   7,
+     6,   9,   4,   2,   6,   5,   9,   9,   4,   7,   3,   2,   4,
+     4,   6,  11,   6,   2,   7,   5,   5,   9,   6,  10,   4,   6,
+     2,   3,   7,   5,   9,   6,   6,   4,   5,   5,  10,   6,   5,
+     7,   4,   5,   7,   6,   7,   7,   6,   5,   7,   3,   7,   4,
+     7,   6,  12,   9,   4,   6,   5,   4,   7,   6,  12,   8,   8,
+     2,   6,   6,   7,   6,   4,   5,   9,   5,   5,   6,   3,   4,
+     9,  13,   2,   2,   4,   6,   6,   8,   5,  17,  12,   7,   9,
+     4,   4,   6,   7,   5,   9,   4,   4,   5,   2,   5,   8,   6,
+     4,   9,   5,   8,   4,   3,   9,   5,   5,   6,   4,   6,   2,
+     2,   9,   3,   7,
+};
+/* aKWOffset[i] is the index into zKWText[] of the start of
+** the text for the i-th keyword. */
+static const unsigned short int aKWOffset[148] = {0,
+     0,   2,   2,   8,   9,  14,  16,  20,  23,  25,  25,  29,  33,
+    36,  41,  46,  48,  53,  54,  59,  62,  65,  67,  69,  78,  81,
+    86,  90,  90,  94,  99, 101, 105, 111, 119, 123, 123, 123, 126,
+   129, 132, 137, 142, 146, 147, 152, 156, 160, 168, 174, 181, 184,
+   184, 187, 189, 195, 198, 206, 211, 216, 219, 222, 226, 236, 239,
+   244, 244, 248, 252, 259, 265, 271, 277, 277, 283, 284, 288, 295,
+   299, 306, 312, 324, 333, 335, 341, 346, 348, 355, 359, 370, 377,
+   378, 385, 391, 397, 402, 408, 412, 415, 424, 429, 433, 439, 441,
+   444, 453, 455, 457, 466, 470, 476, 482, 490, 495, 495, 495, 511,
+   520, 523, 527, 532, 539, 544, 553, 557, 560, 565, 567, 571, 579,
+   585, 588, 597, 602, 610, 610, 614, 623, 628, 633, 639, 642, 645,
+   648, 650, 655, 659,
+};
+/* aKWCode[i] is the parser symbol code for the i-th keyword */
+static const unsigned char aKWCode[148] = {0,
+  TK_REINDEX,    TK_INDEXED,    TK_INDEX,      TK_DESC,       TK_ESCAPE,
+  TK_EACH,       TK_CHECK,      TK_KEY,        TK_BEFORE,     TK_FOREIGN,
+  TK_FOR,        TK_IGNORE,     TK_LIKE_KW,    TK_EXPLAIN,    TK_INSTEAD,
+  TK_ADD,        TK_DATABASE,   TK_AS,         TK_SELECT,     TK_TABLE,
+  TK_JOIN_KW,    TK_THEN,       TK_END,        TK_DEFERRABLE, TK_ELSE,
+  TK_EXCLUDE,    TK_DELETE,     TK_TEMP,       TK_TEMP,       TK_OR,
+  TK_ISNULL,     TK_NULLS,      TK_SAVEPOINT,  TK_INTERSECT,  TK_TIES,
+  TK_NOTNULL,    TK_NOT,        TK_NO,         TK_NULL,       TK_LIKE_KW,
+  TK_EXCEPT,     TK_TRANSACTION,TK_ACTION,     TK_ON,         TK_JOIN_KW,
+  TK_ALTER,      TK_RAISE,      TK_EXCLUSIVE,  TK_EXISTS,     TK_CONSTRAINT,
+  TK_INTO,       TK_OFFSET,     TK_OF,         TK_SET,        TK_TRIGGER,
+  TK_RANGE,      TK_GENERATED,  TK_DETACH,     TK_HAVING,     TK_LIKE_KW,
+  TK_BEGIN,      TK_JOIN_KW,    TK_REFERENCES, TK_UNIQUE,     TK_QUERY,
+  TK_WITHOUT,    TK_WITH,       TK_JOIN_KW,    TK_RELEASE,    TK_ATTACH,
+  TK_BETWEEN,    TK_NOTHING,    TK_GROUPS,     TK_GROUP,      TK_CASCADE,
+  TK_ASC,        TK_DEFAULT,    TK_CASE,       TK_COLLATE,    TK_CREATE,
+  TK_CTIME_KW,   TK_IMMEDIATE,  TK_JOIN,       TK_INSERT,     TK_MATCH,
+  TK_PLAN,       TK_ANALYZE,    TK_PRAGMA,     TK_MATERIALIZED, TK_DEFERRED,
+  TK_DISTINCT,   TK_IS,         TK_UPDATE,     TK_VALUES,     TK_VIRTUAL,
+  TK_ALWAYS,     TK_WHEN,       TK_WHERE,      TK_RECURSIVE,  TK_ABORT,
+  TK_AFTER,      TK_RENAME,     TK_AND,        TK_DROP,       TK_PARTITION,
+  TK_AUTOINCR,   TK_TO,         TK_IN,         TK_CAST,       TK_COLUMNKW,
+  TK_COMMIT,     TK_CONFLICT,   TK_JOIN_KW,    TK_CTIME_KW,   TK_CTIME_KW,
+  TK_CURRENT,    TK_PRECEDING,  TK_FAIL,       TK_LAST,       TK_FILTER,
+  TK_REPLACE,    TK_FIRST,      TK_FOLLOWING,  TK_FROM,       TK_JOIN_KW,
+  TK_LIMIT,      TK_IF,         TK_ORDER,      TK_RESTRICT,   TK_OTHERS,
+  TK_OVER,       TK_RETURNING,  TK_JOIN_KW,    TK_ROLLBACK,   TK_ROWS,
+  TK_ROW,        TK_UNBOUNDED,  TK_UNION,      TK_USING,      TK_VACUUM,
+  TK_VIEW,       TK_WINDOW,     TK_DO,         TK_BY,         TK_INITIALLY,
+  TK_ALL,        TK_PRIMARY,
+};
+/* Hash table decoded:
+**   0: INSERT
+**   1: IS
+**   2: ROLLBACK TRIGGER
+**   3: IMMEDIATE
+**   4: PARTITION
+**   5: TEMP
+**   6:
+**   7:
+**   8: VALUES WITHOUT
+**   9:
+**  10: MATCH
+**  11: NOTHING
+**  12:
+**  13: OF
+**  14: TIES IGNORE
+**  15: PLAN
+**  16: INSTEAD INDEXED
+**  17:
+**  18: TRANSACTION RIGHT
+**  19: WHEN
+**  20: SET HAVING
+**  21: MATERIALIZED IF
+**  22: ROWS
+**  23: SELECT
+**  24:
+**  25:
+**  26: VACUUM SAVEPOINT
+**  27:
+**  28: LIKE UNION VIRTUAL REFERENCES
+**  29: RESTRICT
+**  30:
+**  31: THEN REGEXP
+**  32: TO
+**  33:
+**  34: BEFORE
+**  35:
+**  36:
+**  37: FOLLOWING COLLATE CASCADE
+**  38: CREATE
+**  39:
+**  40: CASE REINDEX
+**  41: EACH
+**  42:
+**  43: QUERY
+**  44: AND ADD
+**  45: PRIMARY ANALYZE
+**  46:
+**  47: ROW ASC DETACH
+**  48: CURRENT_TIME CURRENT_DATE
+**  49:
+**  50:
+**  51: EXCLUSIVE TEMPORARY
+**  52:
+**  53: DEFERRED
+**  54: DEFERRABLE
+**  55:
+**  56: DATABASE
+**  57:
+**  58: DELETE VIEW GENERATED
+**  59: ATTACH
+**  60: END
+**  61: EXCLUDE
+**  62: ESCAPE DESC
+**  63: GLOB
+**  64: WINDOW ELSE
+**  65: COLUMN
+**  66: FIRST
+**  67:
+**  68: GROUPS ALL
+**  69: DISTINCT DROP KEY
+**  70: BETWEEN
+**  71: INITIALLY
+**  72: BEGIN
+**  73: FILTER CHECK ACTION
+**  74: GROUP INDEX
+**  75:
+**  76: EXISTS DEFAULT
+**  77:
+**  78: FOR CURRENT_TIMESTAMP
+**  79: EXCEPT
+**  80:
+**  81: CROSS
+**  82:
+**  83:
+**  84:
+**  85: CAST
+**  86: FOREIGN AUTOINCREMENT
+**  87: COMMIT
+**  88: CURRENT AFTER ALTER
+**  89: FULL FAIL CONFLICT
+**  90: EXPLAIN
+**  91: CONSTRAINT
+**  92: FROM ALWAYS
+**  93:
+**  94: ABORT
+**  95:
+**  96: AS DO
+**  97: REPLACE WITH RELEASE
+**  98: BY RENAME
+**  99: RANGE RAISE
+** 100: OTHERS
+** 101: USING NULLS
+** 102: PRAGMA
+** 103: JOIN ISNULL OFFSET
+** 104: NOT
+** 105: OR LAST LEFT
+** 106: LIMIT
+** 107:
+** 108:
+** 109: IN
+** 110: INTO
+** 111: OVER RECURSIVE
+** 112: ORDER OUTER
+** 113:
+** 114: INTERSECT UNBOUNDED
+** 115:
+** 116:
+** 117: RETURNING ON
+** 118:
+** 119: WHERE
+** 120: NO INNER
+** 121: NULL
+** 122:
+** 123: TABLE
+** 124: NATURAL NOTNULL
+** 125: PRECEDING
+** 126: UPDATE UNIQUE
+*/
+/* Check to see if z[0..n-1] is a keyword. If it is, write the
+** parser symbol code for that keyword into *pType.  Always
+** return the integer n (the length of the token). */
+static int keywordCode(const char *z, int n, int *pType){
+  int i, j;
+  const char *zKW;
+  assert( n>=2 );
+  i = ((charMap(z[0])*4) ^ (charMap(z[n-1])*3) ^ n*1) % 127;
+  for(i=(int)aKWHash[i]; i>0; i=aKWNext[i]){
+    if( aKWLen[i]!=n ) continue;
+    zKW = &zKWText[aKWOffset[i]];
+#ifdef SQLITE_ASCII
+    if( (z[0]&~0x20)!=zKW[0] ) continue;
+    if( (z[1]&~0x20)!=zKW[1] ) continue;
+    j = 2;
+    while( j<n && (z[j]&~0x20)==zKW[j] ){ j++; }
+#endif
+#ifdef SQLITE_EBCDIC
+    if( toupper(z[0])!=zKW[0] ) continue;
+    if( toupper(z[1])!=zKW[1] ) continue;
+    j = 2;
+    while( j<n && toupper(z[j])==zKW[j] ){ j++; }
+#endif
+    if( j<n ) continue;
+    testcase( i==1 ); /* REINDEX */
+    testcase( i==2 ); /* INDEXED */
+    testcase( i==3 ); /* INDEX */
+    testcase( i==4 ); /* DESC */
+    testcase( i==5 ); /* ESCAPE */
+    testcase( i==6 ); /* EACH */
+    testcase( i==7 ); /* CHECK */
+    testcase( i==8 ); /* KEY */
+    testcase( i==9 ); /* BEFORE */
+    testcase( i==10 ); /* FOREIGN */
+    testcase( i==11 ); /* FOR */
+    testcase( i==12 ); /* IGNORE */
+    testcase( i==13 ); /* REGEXP */
+    testcase( i==14 ); /* EXPLAIN */
+    testcase( i==15 ); /* INSTEAD */
+    testcase( i==16 ); /* ADD */
+    testcase( i==17 ); /* DATABASE */
+    testcase( i==18 ); /* AS */
+    testcase( i==19 ); /* SELECT */
+    testcase( i==20 ); /* TABLE */
+    testcase( i==21 ); /* LEFT */
+    testcase( i==22 ); /* THEN */
+    testcase( i==23 ); /* END */
+    testcase( i==24 ); /* DEFERRABLE */
+    testcase( i==25 ); /* ELSE */
+    testcase( i==26 ); /* EXCLUDE */
+    testcase( i==27 ); /* DELETE */
+    testcase( i==28 ); /* TEMPORARY */
+    testcase( i==29 ); /* TEMP */
+    testcase( i==30 ); /* OR */
+    testcase( i==31 ); /* ISNULL */
+    testcase( i==32 ); /* NULLS */
+    testcase( i==33 ); /* SAVEPOINT */
+    testcase( i==34 ); /* INTERSECT */
+    testcase( i==35 ); /* TIES */
+    testcase( i==36 ); /* NOTNULL */
+    testcase( i==37 ); /* NOT */
+    testcase( i==38 ); /* NO */
+    testcase( i==39 ); /* NULL */
+    testcase( i==40 ); /* LIKE */
+    testcase( i==41 ); /* EXCEPT */
+    testcase( i==42 ); /* TRANSACTION */
+    testcase( i==43 ); /* ACTION */
+    testcase( i==44 ); /* ON */
+    testcase( i==45 ); /* NATURAL */
+    testcase( i==46 ); /* ALTER */
+    testcase( i==47 ); /* RAISE */
+    testcase( i==48 ); /* EXCLUSIVE */
+    testcase( i==49 ); /* EXISTS */
+    testcase( i==50 ); /* CONSTRAINT */
+    testcase( i==51 ); /* INTO */
+    testcase( i==52 ); /* OFFSET */
+    testcase( i==53 ); /* OF */
+    testcase( i==54 ); /* SET */
+    testcase( i==55 ); /* TRIGGER */
+    testcase( i==56 ); /* RANGE */
+    testcase( i==57 ); /* GENERATED */
+    testcase( i==58 ); /* DETACH */
+    testcase( i==59 ); /* HAVING */
+    testcase( i==60 ); /* GLOB */
+    testcase( i==61 ); /* BEGIN */
+    testcase( i==62 ); /* INNER */
+    testcase( i==63 ); /* REFERENCES */
+    testcase( i==64 ); /* UNIQUE */
+    testcase( i==65 ); /* QUERY */
+    testcase( i==66 ); /* WITHOUT */
+    testcase( i==67 ); /* WITH */
+    testcase( i==68 ); /* OUTER */
+    testcase( i==69 ); /* RELEASE */
+    testcase( i==70 ); /* ATTACH */
+    testcase( i==71 ); /* BETWEEN */
+    testcase( i==72 ); /* NOTHING */
+    testcase( i==73 ); /* GROUPS */
+    testcase( i==74 ); /* GROUP */
+    testcase( i==75 ); /* CASCADE */
+    testcase( i==76 ); /* ASC */
+    testcase( i==77 ); /* DEFAULT */
+    testcase( i==78 ); /* CASE */
+    testcase( i==79 ); /* COLLATE */
+    testcase( i==80 ); /* CREATE */
+    testcase( i==81 ); /* CURRENT_DATE */
+    testcase( i==82 ); /* IMMEDIATE */
+    testcase( i==83 ); /* JOIN */
+    testcase( i==84 ); /* INSERT */
+    testcase( i==85 ); /* MATCH */
+    testcase( i==86 ); /* PLAN */
+    testcase( i==87 ); /* ANALYZE */
+    testcase( i==88 ); /* PRAGMA */
+    testcase( i==89 ); /* MATERIALIZED */
+    testcase( i==90 ); /* DEFERRED */
+    testcase( i==91 ); /* DISTINCT */
+    testcase( i==92 ); /* IS */
+    testcase( i==93 ); /* UPDATE */
+    testcase( i==94 ); /* VALUES */
+    testcase( i==95 ); /* VIRTUAL */
+    testcase( i==96 ); /* ALWAYS */
+    testcase( i==97 ); /* WHEN */
+    testcase( i==98 ); /* WHERE */
+    testcase( i==99 ); /* RECURSIVE */
+    testcase( i==100 ); /* ABORT */
+    testcase( i==101 ); /* AFTER */
+    testcase( i==102 ); /* RENAME */
+    testcase( i==103 ); /* AND */
+    testcase( i==104 ); /* DROP */
+    testcase( i==105 ); /* PARTITION */
+    testcase( i==106 ); /* AUTOINCREMENT */
+    testcase( i==107 ); /* TO */
+    testcase( i==108 ); /* IN */
+    testcase( i==109 ); /* CAST */
+    testcase( i==110 ); /* COLUMN */
+    testcase( i==111 ); /* COMMIT */
+    testcase( i==112 ); /* CONFLICT */
+    testcase( i==113 ); /* CROSS */
+    testcase( i==114 ); /* CURRENT_TIMESTAMP */
+    testcase( i==115 ); /* CURRENT_TIME */
+    testcase( i==116 ); /* CURRENT */
+    testcase( i==117 ); /* PRECEDING */
+    testcase( i==118 ); /* FAIL */
+    testcase( i==119 ); /* LAST */
+    testcase( i==120 ); /* FILTER */
+    testcase( i==121 ); /* REPLACE */
+    testcase( i==122 ); /* FIRST */
+    testcase( i==123 ); /* FOLLOWING */
+    testcase( i==124 ); /* FROM */
+    testcase( i==125 ); /* FULL */
+    testcase( i==126 ); /* LIMIT */
+    testcase( i==127 ); /* IF */
+    testcase( i==128 ); /* ORDER */
+    testcase( i==129 ); /* RESTRICT */
+    testcase( i==130 ); /* OTHERS */
+    testcase( i==131 ); /* OVER */
+    testcase( i==132 ); /* RETURNING */
+    testcase( i==133 ); /* RIGHT */
+    testcase( i==134 ); /* ROLLBACK */
+    testcase( i==135 ); /* ROWS */
+    testcase( i==136 ); /* ROW */
+    testcase( i==137 ); /* UNBOUNDED */
+    testcase( i==138 ); /* UNION */
+    testcase( i==139 ); /* USING */
+    testcase( i==140 ); /* VACUUM */
+    testcase( i==141 ); /* VIEW */
+    testcase( i==142 ); /* WINDOW */
+    testcase( i==143 ); /* DO */
+    testcase( i==144 ); /* BY */
+    testcase( i==145 ); /* INITIALLY */
+    testcase( i==146 ); /* ALL */
+    testcase( i==147 ); /* PRIMARY */
+    *pType = aKWCode[i];
+    break;
+  }
+  return n;
+}
+SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char *z, int n){
+  int id = TK_ID;
+  if( n>=2 ) keywordCode((char*)z, n, &id);
+  return id;
+}
+#define SQLITE_N_KEYWORD 147
+SQLITE_API int sqlite3_keyword_name(int i,const char **pzName,int *pnName){
+  if( i<0 || i>=SQLITE_N_KEYWORD ) return SQLITE_ERROR;
+  i++;
+  *pzName = zKWText + aKWOffset[i];
+  *pnName = aKWLen[i];
+  return SQLITE_OK;
+}
+SQLITE_API int sqlite3_keyword_count(void){ return SQLITE_N_KEYWORD; }
+SQLITE_API int sqlite3_keyword_check(const char *zName, int nName){
+  return TK_ID!=sqlite3KeywordCode((const u8*)zName, nName);
+}
+
+/************** End of keywordhash.h *****************************************/
+/************** Continuing where we left off in tokenize.c *******************/
+
+
+/*
+** If X is a character that can be used in an identifier then
+** IdChar(X) will be true.  Otherwise it is false.
+**
+** For ASCII, any character with the high-order bit set is
+** allowed in an identifier.  For 7-bit characters,
+** sqlite3IsIdChar[X] must be 1.
+**
+** For EBCDIC, the rules are more complex but have the same
+** end result.
+**
+** Ticket #1066.  the SQL standard does not allow '$' in the
+** middle of identifiers.  But many SQL implementations do.
+** SQLite will allow '$' in identifiers for compatibility.
+** But the feature is undocumented.
+*/
+#ifdef SQLITE_ASCII
+#define IdChar(C)  ((sqlite3CtypeMap[(unsigned char)C]&0x46)!=0)
+#endif
+#ifdef SQLITE_EBCDIC
+SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[] = {
+/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
+    0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 4x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0,  /* 5x */
+    0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0,  /* 6x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,  /* 7x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0,  /* 8x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0,  /* 9x */
+    1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0,  /* Ax */
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* Bx */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,  /* Cx */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,  /* Dx */
+    0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,  /* Ex */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0,  /* Fx */
+};
+#define IdChar(C)  (((c=C)>=0x42 && sqlite3IsEbcdicIdChar[c-0x40]))
+#endif
+
+/* Make the IdChar function accessible from ctime.c and alter.c */
+SQLITE_PRIVATE int sqlite3IsIdChar(u8 c){ return IdChar(c); }
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Return the id of the next token in string (*pz). Before returning, set
+** (*pz) to point to the byte following the parsed token.
+*/
+static int getToken(const unsigned char **pz){
+  const unsigned char *z = *pz;
+  int t;                          /* Token type to return */
+  do {
+    z += sqlite3GetToken(z, &t);
+  }while( t==TK_SPACE );
+  if( t==TK_ID
+   || t==TK_STRING
+   || t==TK_JOIN_KW
+   || t==TK_WINDOW
+   || t==TK_OVER
+   || sqlite3ParserFallback(t)==TK_ID
+  ){
+    t = TK_ID;
+  }
+  *pz = z;
+  return t;
+}
+
+/*
+** The following three functions are called immediately after the tokenizer
+** reads the keywords WINDOW, OVER and FILTER, respectively, to determine
+** whether the token should be treated as a keyword or an SQL identifier.
+** This cannot be handled by the usual lemon %fallback method, due to
+** the ambiguity in some constructions. e.g.
+**
+**   SELECT sum(x) OVER ...
+**
+** In the above, "OVER" might be a keyword, or it might be an alias for the
+** sum(x) expression. If a "%fallback ID OVER" directive were added to
+** grammar, then SQLite would always treat "OVER" as an alias, making it
+** impossible to call a window-function without a FILTER clause.
+**
+** WINDOW is treated as a keyword if:
+**
+**   * the following token is an identifier, or a keyword that can fallback
+**     to being an identifier, and
+**   * the token after than one is TK_AS.
+**
+** OVER is a keyword if:
+**
+**   * the previous token was TK_RP, and
+**   * the next token is either TK_LP or an identifier.
+**
+** FILTER is a keyword if:
+**
+**   * the previous token was TK_RP, and
+**   * the next token is TK_LP.
+*/
+static int analyzeWindowKeyword(const unsigned char *z){
+  int t;
+  t = getToken(&z);
+  if( t!=TK_ID ) return TK_ID;
+  t = getToken(&z);
+  if( t!=TK_AS ) return TK_ID;
+  return TK_WINDOW;
+}
+static int analyzeOverKeyword(const unsigned char *z, int lastToken){
+  if( lastToken==TK_RP ){
+    int t = getToken(&z);
+    if( t==TK_LP || t==TK_ID ) return TK_OVER;
+  }
+  return TK_ID;
+}
+static int analyzeFilterKeyword(const unsigned char *z, int lastToken){
+  if( lastToken==TK_RP && getToken(&z)==TK_LP ){
+    return TK_FILTER;
+  }
+  return TK_ID;
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** Return the length (in bytes) of the token that begins at z[0].
+** Store the token type in *tokenType before returning.
+*/
+SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
+  int i, c;
+  switch( aiClass[*z] ){  /* Switch on the character-class of the first byte
+                          ** of the token. See the comment on the CC_ defines
+                          ** above. */
+    case CC_SPACE: {
+      testcase( z[0]==' ' );
+      testcase( z[0]=='\t' );
+      testcase( z[0]=='\n' );
+      testcase( z[0]=='\f' );
+      testcase( z[0]=='\r' );
+      for(i=1; sqlite3Isspace(z[i]); i++){}
+      *tokenType = TK_SPACE;
+      return i;
+    }
+    case CC_MINUS: {
+      if( z[1]=='-' ){
+        for(i=2; (c=z[i])!=0 && c!='\n'; i++){}
+        *tokenType = TK_COMMENT;
+        return i;
+      }else if( z[1]=='>' ){
+        *tokenType = TK_PTR;
+        return 2 + (z[2]=='>');
+      }
+      *tokenType = TK_MINUS;
+      return 1;
+    }
+    case CC_LP: {
+      *tokenType = TK_LP;
+      return 1;
+    }
+    case CC_RP: {
+      *tokenType = TK_RP;
+      return 1;
+    }
+    case CC_SEMI: {
+      *tokenType = TK_SEMI;
+      return 1;
+    }
+    case CC_PLUS: {
+      *tokenType = TK_PLUS;
+      return 1;
+    }
+    case CC_STAR: {
+      *tokenType = TK_STAR;
+      return 1;
+    }
+    case CC_SLASH: {
+      if( z[1]!='*' || z[2]==0 ){
+        *tokenType = TK_SLASH;
+        return 1;
+      }
+      for(i=3, c=z[2]; (c!='*' || z[i]!='/') && (c=z[i])!=0; i++){}
+      if( c ) i++;
+      *tokenType = TK_COMMENT;
+      return i;
+    }
+    case CC_PERCENT: {
+      *tokenType = TK_REM;
+      return 1;
+    }
+    case CC_EQ: {
+      *tokenType = TK_EQ;
+      return 1 + (z[1]=='=');
+    }
+    case CC_LT: {
+      if( (c=z[1])=='=' ){
+        *tokenType = TK_LE;
+        return 2;
+      }else if( c=='>' ){
+        *tokenType = TK_NE;
+        return 2;
+      }else if( c=='<' ){
+        *tokenType = TK_LSHIFT;
+        return 2;
+      }else{
+        *tokenType = TK_LT;
+        return 1;
+      }
+    }
+    case CC_GT: {
+      if( (c=z[1])=='=' ){
+        *tokenType = TK_GE;
+        return 2;
+      }else if( c=='>' ){
+        *tokenType = TK_RSHIFT;
+        return 2;
+      }else{
+        *tokenType = TK_GT;
+        return 1;
+      }
+    }
+    case CC_BANG: {
+      if( z[1]!='=' ){
+        *tokenType = TK_ILLEGAL;
+        return 1;
+      }else{
+        *tokenType = TK_NE;
+        return 2;
+      }
+    }
+    case CC_PIPE: {
+      if( z[1]!='|' ){
+        *tokenType = TK_BITOR;
+        return 1;
+      }else{
+        *tokenType = TK_CONCAT;
+        return 2;
+      }
+    }
+    case CC_COMMA: {
+      *tokenType = TK_COMMA;
+      return 1;
+    }
+    case CC_AND: {
+      *tokenType = TK_BITAND;
+      return 1;
+    }
+    case CC_TILDA: {
+      *tokenType = TK_BITNOT;
+      return 1;
+    }
+    case CC_QUOTE: {
+      int delim = z[0];
+      testcase( delim=='`' );
+      testcase( delim=='\'' );
+      testcase( delim=='"' );
+      for(i=1; (c=z[i])!=0; i++){
+        if( c==delim ){
+          if( z[i+1]==delim ){
+            i++;
+          }else{
+            break;
+          }
+        }
+      }
+      if( c=='\'' ){
+        *tokenType = TK_STRING;
+        return i+1;
+      }else if( c!=0 ){
+        *tokenType = TK_ID;
+        return i+1;
+      }else{
+        *tokenType = TK_ILLEGAL;
+        return i;
+      }
+    }
+    case CC_DOT: {
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      if( !sqlite3Isdigit(z[1]) )
+#endif
+      {
+        *tokenType = TK_DOT;
+        return 1;
+      }
+      /* If the next character is a digit, this is a floating point
+      ** number that begins with ".".  Fall thru into the next case */
+      /* no break */ deliberate_fall_through
+    }
+    case CC_DIGIT: {
+      testcase( z[0]=='0' );  testcase( z[0]=='1' );  testcase( z[0]=='2' );
+      testcase( z[0]=='3' );  testcase( z[0]=='4' );  testcase( z[0]=='5' );
+      testcase( z[0]=='6' );  testcase( z[0]=='7' );  testcase( z[0]=='8' );
+      testcase( z[0]=='9' );  testcase( z[0]=='.' );
+      *tokenType = TK_INTEGER;
+#ifndef SQLITE_OMIT_HEX_INTEGER
+      if( z[0]=='0' && (z[1]=='x' || z[1]=='X') && sqlite3Isxdigit(z[2]) ){
+        for(i=3; 1; i++){
+          if( sqlite3Isxdigit(z[i])==0 ){
+            if( z[i]==SQLITE_DIGIT_SEPARATOR ){
+              *tokenType = TK_QNUMBER;
+            }else{
+              break;
+            }
+          }
+        }
+      }else
+#endif
+        {
+        for(i=0; 1; i++){
+          if( sqlite3Isdigit(z[i])==0 ){
+            if( z[i]==SQLITE_DIGIT_SEPARATOR ){
+              *tokenType = TK_QNUMBER;
+            }else{
+              break;
+            }
+          }
+        }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+        if( z[i]=='.' ){
+          if( *tokenType==TK_INTEGER ) *tokenType = TK_FLOAT;
+          for(i++; 1; i++){
+            if( sqlite3Isdigit(z[i])==0 ){
+              if( z[i]==SQLITE_DIGIT_SEPARATOR ){
+                *tokenType = TK_QNUMBER;
+              }else{
+                break;
+              }
+            }
+          }
+        }
+        if( (z[i]=='e' || z[i]=='E') &&
+             ( sqlite3Isdigit(z[i+1])
+              || ((z[i+1]=='+' || z[i+1]=='-') && sqlite3Isdigit(z[i+2]))
+             )
+        ){
+          if( *tokenType==TK_INTEGER ) *tokenType = TK_FLOAT;
+          for(i+=2; 1; i++){
+            if( sqlite3Isdigit(z[i])==0 ){
+              if( z[i]==SQLITE_DIGIT_SEPARATOR ){
+                *tokenType = TK_QNUMBER;
+              }else{
+                break;
+              }
+            }
+          }
+        }
+#endif
+      }
+      while( IdChar(z[i]) ){
+        *tokenType = TK_ILLEGAL;
+        i++;
+      }
+      return i;
+    }
+    case CC_QUOTE2: {
+      for(i=1, c=z[0]; c!=']' && (c=z[i])!=0; i++){}
+      *tokenType = c==']' ? TK_ID : TK_ILLEGAL;
+      return i;
+    }
+    case CC_VARNUM: {
+      *tokenType = TK_VARIABLE;
+      for(i=1; sqlite3Isdigit(z[i]); i++){}
+      return i;
+    }
+    case CC_DOLLAR:
+    case CC_VARALPHA: {
+      int n = 0;
+      testcase( z[0]=='$' );  testcase( z[0]=='@' );
+      testcase( z[0]==':' );  testcase( z[0]=='#' );
+      *tokenType = TK_VARIABLE;
+      for(i=1; (c=z[i])!=0; i++){
+        if( IdChar(c) ){
+          n++;
+#ifndef SQLITE_OMIT_TCL_VARIABLE
+        }else if( c=='(' && n>0 ){
+          do{
+            i++;
+          }while( (c=z[i])!=0 && !sqlite3Isspace(c) && c!=')' );
+          if( c==')' ){
+            i++;
+          }else{
+            *tokenType = TK_ILLEGAL;
+          }
+          break;
+        }else if( c==':' && z[i+1]==':' ){
+          i++;
+#endif
+        }else{
+          break;
+        }
+      }
+      if( n==0 ) *tokenType = TK_ILLEGAL;
+      return i;
+    }
+    case CC_KYWD0: {
+      if( aiClass[z[1]]>CC_KYWD ){ i = 1;  break; }
+      for(i=2; aiClass[z[i]]<=CC_KYWD; i++){}
+      if( IdChar(z[i]) ){
+        /* This token started out using characters that can appear in keywords,
+        ** but z[i] is a character not allowed within keywords, so this must
+        ** be an identifier instead */
+        i++;
+        break;
+      }
+      *tokenType = TK_ID;
+      return keywordCode((char*)z, i, tokenType);
+    }
+    case CC_X: {
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+      testcase( z[0]=='x' ); testcase( z[0]=='X' );
+      if( z[1]=='\'' ){
+        *tokenType = TK_BLOB;
+        for(i=2; sqlite3Isxdigit(z[i]); i++){}
+        if( z[i]!='\'' || i%2 ){
+          *tokenType = TK_ILLEGAL;
+          while( z[i] && z[i]!='\'' ){ i++; }
+        }
+        if( z[i] ) i++;
+        return i;
+      }
+#endif
+      /* If it is not a BLOB literal, then it must be an ID, since no
+      ** SQL keywords start with the letter 'x'.  Fall through */
+      /* no break */ deliberate_fall_through
+    }
+    case CC_KYWD:
+    case CC_ID: {
+      i = 1;
+      break;
+    }
+    case CC_BOM: {
+      if( z[1]==0xbb && z[2]==0xbf ){
+        *tokenType = TK_SPACE;
+        return 3;
+      }
+      i = 1;
+      break;
+    }
+    case CC_NUL: {
+      *tokenType = TK_ILLEGAL;
+      return 0;
+    }
+    default: {
+      *tokenType = TK_ILLEGAL;
+      return 1;
+    }
+  }
+  while( IdChar(z[i]) ){ i++; }
+  *tokenType = TK_ID;
+  return i;
+}
+
+/*
+** Run the parser on the given SQL string.
+*/
+SQLITE_PRIVATE int sqlite3RunParser(Parse *pParse, const char *zSql){
+  int nErr = 0;                   /* Number of errors encountered */
+  void *pEngine;                  /* The LEMON-generated LALR(1) parser */
+  int n = 0;                      /* Length of the next token token */
+  int tokenType;                  /* type of the next token */
+  int lastTokenParsed = -1;       /* type of the previous token */
+  sqlite3 *db = pParse->db;       /* The database connection */
+  int mxSqlLen;                   /* Max length of an SQL string */
+  Parse *pParentParse = 0;        /* Outer parse context, if any */
+#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
+  yyParser sEngine;    /* Space to hold the Lemon-generated Parser object */
+#endif
+  VVA_ONLY( u8 startedWithOom = db->mallocFailed );
+
+  assert( zSql!=0 );
+  mxSqlLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
+  if( db->nVdbeActive==0 ){
+    AtomicStore(&db->u1.isInterrupted, 0);
+  }
+  pParse->rc = SQLITE_OK;
+  pParse->zTail = zSql;
+#ifdef SQLITE_DEBUG
+  if( db->flags & SQLITE_ParserTrace ){
+    printf("parser: [[[%s]]]\n", zSql);
+    sqlite3ParserTrace(stdout, "parser: ");
+  }else{
+    sqlite3ParserTrace(0, 0);
+  }
+#endif
+#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
+  pEngine = &sEngine;
+  sqlite3ParserInit(pEngine, pParse);
+#else
+  pEngine = sqlite3ParserAlloc(sqlite3Malloc, pParse);
+  if( pEngine==0 ){
+    sqlite3OomFault(db);
+    return SQLITE_NOMEM_BKPT;
+  }
+#endif
+  assert( pParse->pNewTable==0 );
+  assert( pParse->pNewTrigger==0 );
+  assert( pParse->nVar==0 );
+  assert( pParse->pVList==0 );
+  pParentParse = db->pParse;
+  db->pParse = pParse;
+  while( 1 ){
+    n = sqlite3GetToken((u8*)zSql, &tokenType);
+    mxSqlLen -= n;
+    if( mxSqlLen<0 ){
+      pParse->rc = SQLITE_TOOBIG;
+      pParse->nErr++;
+      break;
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( tokenType>=TK_WINDOW ){
+      assert( tokenType==TK_SPACE || tokenType==TK_OVER || tokenType==TK_FILTER
+           || tokenType==TK_ILLEGAL || tokenType==TK_WINDOW
+           || tokenType==TK_QNUMBER || tokenType==TK_COMMENT
+      );
+#else
+    if( tokenType>=TK_SPACE ){
+      assert( tokenType==TK_SPACE || tokenType==TK_ILLEGAL
+           || tokenType==TK_QNUMBER || tokenType==TK_COMMENT
+      );
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+      if( AtomicLoad(&db->u1.isInterrupted) ){
+        pParse->rc = SQLITE_INTERRUPT;
+        pParse->nErr++;
+        break;
+      }
+      if( tokenType==TK_SPACE ){
+        zSql += n;
+        continue;
+      }
+      if( zSql[0]==0 ){
+        /* Upon reaching the end of input, call the parser two more times
+        ** with tokens TK_SEMI and 0, in that order. */
+        if( lastTokenParsed==TK_SEMI ){
+          tokenType = 0;
+        }else if( lastTokenParsed==0 ){
+          break;
+        }else{
+          tokenType = TK_SEMI;
+        }
+        n = 0;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      }else if( tokenType==TK_WINDOW ){
+        assert( n==6 );
+        tokenType = analyzeWindowKeyword((const u8*)&zSql[6]);
+      }else if( tokenType==TK_OVER ){
+        assert( n==4 );
+        tokenType = analyzeOverKeyword((const u8*)&zSql[4], lastTokenParsed);
+      }else if( tokenType==TK_FILTER ){
+        assert( n==6 );
+        tokenType = analyzeFilterKeyword((const u8*)&zSql[6], lastTokenParsed);
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+      }else if( tokenType==TK_COMMENT && (db->flags & SQLITE_Comments)!=0 ){
+        zSql += n;
+        continue;
+      }else if( tokenType!=TK_QNUMBER ){
+        Token x;
+        x.z = zSql;
+        x.n = n;
+        sqlite3ErrorMsg(pParse, "unrecognized token: \"%T\"", &x);
+        break;
+      }
+    }
+    pParse->sLastToken.z = zSql;
+    pParse->sLastToken.n = n;
+    sqlite3Parser(pEngine, tokenType, pParse->sLastToken);
+    lastTokenParsed = tokenType;
+    zSql += n;
+    assert( db->mallocFailed==0 || pParse->rc!=SQLITE_OK || startedWithOom );
+    if( pParse->rc!=SQLITE_OK ) break;
+  }
+  assert( nErr==0 );
+#ifdef YYTRACKMAXSTACKDEPTH
+  sqlite3_mutex_enter(sqlite3MallocMutex());
+  sqlite3StatusHighwater(SQLITE_STATUS_PARSER_STACK,
+      sqlite3ParserStackPeak(pEngine)
+  );
+  sqlite3_mutex_leave(sqlite3MallocMutex());
+#endif /* YYDEBUG */
+#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
+  sqlite3ParserFinalize(pEngine);
+#else
+  sqlite3ParserFree(pEngine, sqlite3_free);
+#endif
+  if( db->mallocFailed ){
+    pParse->rc = SQLITE_NOMEM_BKPT;
+  }
+  if( pParse->zErrMsg || (pParse->rc!=SQLITE_OK && pParse->rc!=SQLITE_DONE) ){
+    if( pParse->zErrMsg==0 ){
+      pParse->zErrMsg = sqlite3MPrintf(db, "%s", sqlite3ErrStr(pParse->rc));
+    }
+    if( (pParse->prepFlags & SQLITE_PREPARE_DONT_LOG)==0 ){
+      sqlite3_log(pParse->rc, "%s in \"%s\"", pParse->zErrMsg, pParse->zTail);
+    }
+    nErr++;
+  }
+  pParse->zTail = zSql;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3_free(pParse->apVtabLock);
+#endif
+
+  if( pParse->pNewTable && !IN_SPECIAL_PARSE ){
+    /* If the pParse->declareVtab flag is set, do not delete any table
+    ** structure built up in pParse->pNewTable. The calling code (see vtab.c)
+    ** will take responsibility for freeing the Table structure.
+    */
+    sqlite3DeleteTable(db, pParse->pNewTable);
+  }
+  if( pParse->pNewTrigger && !IN_RENAME_OBJECT ){
+    sqlite3DeleteTrigger(db, pParse->pNewTrigger);
+  }
+  if( pParse->pVList ) sqlite3DbNNFreeNN(db, pParse->pVList);
+  db->pParse = pParentParse;
+  assert( nErr==0 || pParse->rc!=SQLITE_OK );
+  return nErr;
+}
+
+
+#ifdef SQLITE_ENABLE_NORMALIZE
+/*
+** Insert a single space character into pStr if the current string
+** ends with an identifier
+*/
+static void addSpaceSeparator(sqlite3_str *pStr){
+  if( pStr->nChar && sqlite3IsIdChar(pStr->zText[pStr->nChar-1]) ){
+    sqlite3_str_append(pStr, " ", 1);
+  }
+}
+
+/*
+** Compute a normalization of the SQL given by zSql[0..nSql-1].  Return
+** the normalization in space obtained from sqlite3DbMalloc().  Or return
+** NULL if anything goes wrong or if zSql is NULL.
+*/
+SQLITE_PRIVATE char *sqlite3Normalize(
+  Vdbe *pVdbe,       /* VM being reprepared */
+  const char *zSql   /* The original SQL string */
+){
+  sqlite3 *db;       /* The database connection */
+  int i;             /* Next unread byte of zSql[] */
+  int n;             /* length of current token */
+  int tokenType;     /* type of current token */
+  int prevType = 0;  /* Previous non-whitespace token */
+  int nParen;        /* Number of nested levels of parentheses */
+  int iStartIN;      /* Start of RHS of IN operator in z[] */
+  int nParenAtIN;    /* Value of nParent at start of RHS of IN operator */
+  u32 j;             /* Bytes of normalized SQL generated so far */
+  sqlite3_str *pStr; /* The normalized SQL string under construction */
+
+  db = sqlite3VdbeDb(pVdbe);
+  tokenType = -1;
+  nParen = iStartIN = nParenAtIN = 0;
+  pStr = sqlite3_str_new(db);
+  assert( pStr!=0 );  /* sqlite3_str_new() never returns NULL */
+  for(i=0; zSql[i] && pStr->accError==0; i+=n){
+    if( tokenType!=TK_SPACE ){
+      prevType = tokenType;
+    }
+    n = sqlite3GetToken((unsigned char*)zSql+i, &tokenType);
+    if( NEVER(n<=0) ) break;
+    switch( tokenType ){
+      case TK_COMMENT:
+      case TK_SPACE: {
+        break;
+      }
+      case TK_NULL: {
+        if( prevType==TK_IS || prevType==TK_NOT ){
+          sqlite3_str_append(pStr, " NULL", 5);
+          break;
+        }
+        /* Fall through */
+      }
+      case TK_STRING:
+      case TK_INTEGER:
+      case TK_FLOAT:
+      case TK_VARIABLE:
+      case TK_BLOB: {
+        sqlite3_str_append(pStr, "?", 1);
+        break;
+      }
+      case TK_LP: {
+        nParen++;
+        if( prevType==TK_IN ){
+          iStartIN = pStr->nChar;
+          nParenAtIN = nParen;
+        }
+        sqlite3_str_append(pStr, "(", 1);
+        break;
+      }
+      case TK_RP: {
+        if( iStartIN>0 && nParen==nParenAtIN ){
+          assert( pStr->nChar>=(u32)iStartIN );
+          pStr->nChar = iStartIN+1;
+          sqlite3_str_append(pStr, "?,?,?", 5);
+          iStartIN = 0;
+        }
+        nParen--;
+        sqlite3_str_append(pStr, ")", 1);
+        break;
+      }
+      case TK_ID: {
+        iStartIN = 0;
+        j = pStr->nChar;
+        if( sqlite3Isquote(zSql[i]) ){
+          char *zId = sqlite3DbStrNDup(db, zSql+i, n);
+          int nId;
+          int eType = 0;
+          if( zId==0 ) break;
+          sqlite3Dequote(zId);
+          if( zSql[i]=='"' && sqlite3VdbeUsesDoubleQuotedString(pVdbe, zId) ){
+            sqlite3_str_append(pStr, "?", 1);
+            sqlite3DbFree(db, zId);
+            break;
+          }
+          nId = sqlite3Strlen30(zId);
+          if( sqlite3GetToken((u8*)zId, &eType)==nId && eType==TK_ID ){
+            addSpaceSeparator(pStr);
+            sqlite3_str_append(pStr, zId, nId);
+          }else{
+            sqlite3_str_appendf(pStr, "\"%w\"", zId);
+          }
+          sqlite3DbFree(db, zId);
+        }else{
+          addSpaceSeparator(pStr);
+          sqlite3_str_append(pStr, zSql+i, n);
+        }
+        while( j<pStr->nChar ){
+          pStr->zText[j] = sqlite3Tolower(pStr->zText[j]);
+          j++;
+        }
+        break;
+      }
+      case TK_SELECT: {
+        iStartIN = 0;
+        /* fall through */
+      }
+      default: {
+        if( sqlite3IsIdChar(zSql[i]) ) addSpaceSeparator(pStr);
+        j = pStr->nChar;
+        sqlite3_str_append(pStr, zSql+i, n);
+        while( j<pStr->nChar ){
+          pStr->zText[j] = sqlite3Toupper(pStr->zText[j]);
+          j++;
+        }
+        break;
+      }
+    }
+  }
+  if( tokenType!=TK_SEMI ) sqlite3_str_append(pStr, ";", 1);
+  return sqlite3_str_finish(pStr);
+}
+#endif /* SQLITE_ENABLE_NORMALIZE */
+
+/************** End of tokenize.c ********************************************/
+/************** Begin file complete.c ****************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** An tokenizer for SQL
+**
+** This file contains C code that implements the sqlite3_complete() API.
+** This code used to be part of the tokenizer.c source file.  But by
+** separating it out, the code will be automatically omitted from
+** static links that do not use it.
+*/
+/* #include "sqliteInt.h" */
+#ifndef SQLITE_OMIT_COMPLETE
+
+/*
+** This is defined in tokenize.c.  We just have to import the definition.
+*/
+#ifndef SQLITE_AMALGAMATION
+#ifdef SQLITE_ASCII
+#define IdChar(C)  ((sqlite3CtypeMap[(unsigned char)C]&0x46)!=0)
+#endif
+#ifdef SQLITE_EBCDIC
+SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[];
+#define IdChar(C)  (((c=C)>=0x42 && sqlite3IsEbcdicIdChar[c-0x40]))
+#endif
+#endif /* SQLITE_AMALGAMATION */
+
+
+/*
+** Token types used by the sqlite3_complete() routine.  See the header
+** comments on that procedure for additional information.
+*/
+#define tkSEMI    0
+#define tkWS      1
+#define tkOTHER   2
+#ifndef SQLITE_OMIT_TRIGGER
+#define tkEXPLAIN 3
+#define tkCREATE  4
+#define tkTEMP    5
+#define tkTRIGGER 6
+#define tkEND     7
+#endif
+
+/*
+** Return TRUE if the given SQL string ends in a semicolon.
+**
+** Special handling is require for CREATE TRIGGER statements.
+** Whenever the CREATE TRIGGER keywords are seen, the statement
+** must end with ";END;".
+**
+** This implementation uses a state machine with 8 states:
+**
+**   (0) INVALID   We have not yet seen a non-whitespace character.
+**
+**   (1) START     At the beginning or end of an SQL statement.  This routine
+**                 returns 1 if it ends in the START state and 0 if it ends
+**                 in any other state.
+**
+**   (2) NORMAL    We are in the middle of statement which ends with a single
+**                 semicolon.
+**
+**   (3) EXPLAIN   The keyword EXPLAIN has been seen at the beginning of
+**                 a statement.
+**
+**   (4) CREATE    The keyword CREATE has been seen at the beginning of a
+**                 statement, possibly preceded by EXPLAIN and/or followed by
+**                 TEMP or TEMPORARY
+**
+**   (5) TRIGGER   We are in the middle of a trigger definition that must be
+**                 ended by a semicolon, the keyword END, and another semicolon.
+**
+**   (6) SEMI      We've seen the first semicolon in the ";END;" that occurs at
+**                 the end of a trigger definition.
+**
+**   (7) END       We've seen the ";END" of the ";END;" that occurs at the end
+**                 of a trigger definition.
+**
+** Transitions between states above are determined by tokens extracted
+** from the input.  The following tokens are significant:
+**
+**   (0) tkSEMI      A semicolon.
+**   (1) tkWS        Whitespace.
+**   (2) tkOTHER     Any other SQL token.
+**   (3) tkEXPLAIN   The "explain" keyword.
+**   (4) tkCREATE    The "create" keyword.
+**   (5) tkTEMP      The "temp" or "temporary" keyword.
+**   (6) tkTRIGGER   The "trigger" keyword.
+**   (7) tkEND       The "end" keyword.
+**
+** Whitespace never causes a state transition and is always ignored.
+** This means that a SQL string of all whitespace is invalid.
+**
+** If we compile with SQLITE_OMIT_TRIGGER, all of the computation needed
+** to recognize the end of a trigger can be omitted.  All we have to do
+** is look for a semicolon that is not part of an string or comment.
+*/
+SQLITE_API int sqlite3_complete(const char *zSql){
+  u8 state = 0;   /* Current state, using numbers defined in header comment */
+  u8 token;       /* Value of the next token */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  /* A complex statement machine used to detect the end of a CREATE TRIGGER
+  ** statement.  This is the normal case.
+  */
+  static const u8 trans[8][8] = {
+                     /* Token:                                                */
+     /* State:       **  SEMI  WS  OTHER  EXPLAIN  CREATE  TEMP  TRIGGER  END */
+     /* 0 INVALID: */ {    1,  0,     2,       3,      4,    2,       2,   2, },
+     /* 1   START: */ {    1,  1,     2,       3,      4,    2,       2,   2, },
+     /* 2  NORMAL: */ {    1,  2,     2,       2,      2,    2,       2,   2, },
+     /* 3 EXPLAIN: */ {    1,  3,     3,       2,      4,    2,       2,   2, },
+     /* 4  CREATE: */ {    1,  4,     2,       2,      2,    4,       5,   2, },
+     /* 5 TRIGGER: */ {    6,  5,     5,       5,      5,    5,       5,   5, },
+     /* 6    SEMI: */ {    6,  6,     5,       5,      5,    5,       5,   7, },
+     /* 7     END: */ {    1,  7,     5,       5,      5,    5,       5,   5, },
+  };
+#else
+  /* If triggers are not supported by this compile then the statement machine
+  ** used to detect the end of a statement is much simpler
+  */
+  static const u8 trans[3][3] = {
+                     /* Token:           */
+     /* State:       **  SEMI  WS  OTHER */
+     /* 0 INVALID: */ {    1,  0,     2, },
+     /* 1   START: */ {    1,  1,     2, },
+     /* 2  NORMAL: */ {    1,  2,     2, },
+  };
+#endif /* SQLITE_OMIT_TRIGGER */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zSql==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+
+  while( *zSql ){
+    switch( *zSql ){
+      case ';': {  /* A semicolon */
+        token = tkSEMI;
+        break;
+      }
+      case ' ':
+      case '\r':
+      case '\t':
+      case '\n':
+      case '\f': {  /* White space is ignored */
+        token = tkWS;
+        break;
+      }
+      case '/': {   /* C-style comments */
+        if( zSql[1]!='*' ){
+          token = tkOTHER;
+          break;
+        }
+        zSql += 2;
+        while( zSql[0] && (zSql[0]!='*' || zSql[1]!='/') ){ zSql++; }
+        if( zSql[0]==0 ) return 0;
+        zSql++;
+        token = tkWS;
+        break;
+      }
+      case '-': {   /* SQL-style comments from "--" to end of line */
+        if( zSql[1]!='-' ){
+          token = tkOTHER;
+          break;
+        }
+        while( *zSql && *zSql!='\n' ){ zSql++; }
+        if( *zSql==0 ) return state==1;
+        token = tkWS;
+        break;
+      }
+      case '[': {   /* Microsoft-style identifiers in [...] */
+        zSql++;
+        while( *zSql && *zSql!=']' ){ zSql++; }
+        if( *zSql==0 ) return 0;
+        token = tkOTHER;
+        break;
+      }
+      case '`':     /* Grave-accent quoted symbols used by MySQL */
+      case '"':     /* single- and double-quoted strings */
+      case '\'': {
+        int c = *zSql;
+        zSql++;
+        while( *zSql && *zSql!=c ){ zSql++; }
+        if( *zSql==0 ) return 0;
+        token = tkOTHER;
+        break;
+      }
+      default: {
+#ifdef SQLITE_EBCDIC
+        unsigned char c;
+#endif
+        if( IdChar((u8)*zSql) ){
+          /* Keywords and unquoted identifiers */
+          int nId;
+          for(nId=1; IdChar(zSql[nId]); nId++){}
+#ifdef SQLITE_OMIT_TRIGGER
+          token = tkOTHER;
+#else
+          switch( *zSql ){
+            case 'c': case 'C': {
+              if( nId==6 && sqlite3StrNICmp(zSql, "create", 6)==0 ){
+                token = tkCREATE;
+              }else{
+                token = tkOTHER;
+              }
+              break;
+            }
+            case 't': case 'T': {
+              if( nId==7 && sqlite3StrNICmp(zSql, "trigger", 7)==0 ){
+                token = tkTRIGGER;
+              }else if( nId==4 && sqlite3StrNICmp(zSql, "temp", 4)==0 ){
+                token = tkTEMP;
+              }else if( nId==9 && sqlite3StrNICmp(zSql, "temporary", 9)==0 ){
+                token = tkTEMP;
+              }else{
+                token = tkOTHER;
+              }
+              break;
+            }
+            case 'e':  case 'E': {
+              if( nId==3 && sqlite3StrNICmp(zSql, "end", 3)==0 ){
+                token = tkEND;
+              }else
+#ifndef SQLITE_OMIT_EXPLAIN
+              if( nId==7 && sqlite3StrNICmp(zSql, "explain", 7)==0 ){
+                token = tkEXPLAIN;
+              }else
+#endif
+              {
+                token = tkOTHER;
+              }
+              break;
+            }
+            default: {
+              token = tkOTHER;
+              break;
+            }
+          }
+#endif /* SQLITE_OMIT_TRIGGER */
+          zSql += nId-1;
+        }else{
+          /* Operators and special symbols */
+          token = tkOTHER;
+        }
+        break;
+      }
+    }
+    state = trans[state][token];
+    zSql++;
+  }
+  return state==1;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** This routine is the same as the sqlite3_complete() routine described
+** above, except that the parameter is required to be UTF-16 encoded, not
+** UTF-8.
+*/
+SQLITE_API int sqlite3_complete16(const void *zSql){
+  sqlite3_value *pVal;
+  char const *zSql8;
+  int rc;
+
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+  pVal = sqlite3ValueNew(0);
+  sqlite3ValueSetStr(pVal, -1, zSql, SQLITE_UTF16NATIVE, SQLITE_STATIC);
+  zSql8 = sqlite3ValueText(pVal, SQLITE_UTF8);
+  if( zSql8 ){
+    rc = sqlite3_complete(zSql8);
+  }else{
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  sqlite3ValueFree(pVal);
+  return rc & 0xff;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+#endif /* SQLITE_OMIT_COMPLETE */
+
+/************** End of complete.c ********************************************/
+/************** Begin file main.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Main file for the SQLite library.  The routines in this file
+** implement the programmer interface to the library.  Routines in
+** other files are for internal use by SQLite and should not be
+** accessed by users of the library.
+*/
+/* #include "sqliteInt.h" */
+
+#ifdef SQLITE_ENABLE_FTS3
+/************** Include fts3.h in the middle of main.c ***********************/
+/************** Begin file fts3.h ********************************************/
+/*
+** 2006 Oct 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file is used by programs that want to link against the
+** FTS3 library.  All it does is declare the sqlite3Fts3Init() interface.
+*/
+/* #include "sqlite3.h" */
+
+#if 0
+extern "C" {
+#endif  /* __cplusplus */
+
+SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db);
+
+#if 0
+}  /* extern "C" */
+#endif  /* __cplusplus */
+
+/************** End of fts3.h ************************************************/
+/************** Continuing where we left off in main.c ***********************/
+#endif
+#ifdef SQLITE_ENABLE_RTREE
+/************** Include rtree.h in the middle of main.c **********************/
+/************** Begin file rtree.h *******************************************/
+/*
+** 2008 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file is used by programs that want to link against the
+** RTREE library.  All it does is declare the sqlite3RtreeInit() interface.
+*/
+/* #include "sqlite3.h" */
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+# undef SQLITE_ENABLE_RTREE
+#endif
+
+#if 0
+extern "C" {
+#endif  /* __cplusplus */
+
+SQLITE_PRIVATE int sqlite3RtreeInit(sqlite3 *db);
+
+#if 0
+}  /* extern "C" */
+#endif  /* __cplusplus */
+
+/************** End of rtree.h ***********************************************/
+/************** Continuing where we left off in main.c ***********************/
+#endif
+#if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
+/************** Include sqliteicu.h in the middle of main.c ******************/
+/************** Begin file sqliteicu.h ***************************************/
+/*
+** 2008 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file is used by programs that want to link against the
+** ICU extension.  All it does is declare the sqlite3IcuInit() interface.
+*/
+/* #include "sqlite3.h" */
+
+#if 0
+extern "C" {
+#endif  /* __cplusplus */
+
+SQLITE_PRIVATE int sqlite3IcuInit(sqlite3 *db);
+
+#if 0
+}  /* extern "C" */
+#endif  /* __cplusplus */
+
+/************** End of sqliteicu.h *******************************************/
+/************** Continuing where we left off in main.c ***********************/
+#endif
+
+/*
+** This is an extension initializer that is a no-op and always
+** succeeds, except that it fails if the fault-simulation is set
+** to 500.
+*/
+static int sqlite3TestExtInit(sqlite3 *db){
+  (void)db;
+  return sqlite3FaultSim(500);
+}
+
+
+/*
+** Forward declarations of external module initializer functions
+** for modules that need them.
+*/
+#ifdef SQLITE_ENABLE_FTS5
+SQLITE_PRIVATE int sqlite3Fts5Init(sqlite3*);
+#endif
+#ifdef SQLITE_ENABLE_STMTVTAB
+SQLITE_PRIVATE int sqlite3StmtVtabInit(sqlite3*);
+#endif
+#ifdef SQLITE_EXTRA_AUTOEXT
+int SQLITE_EXTRA_AUTOEXT(sqlite3*);
+#endif
+/*
+** An array of pointers to extension initializer functions for
+** built-in extensions.
+*/
+static int (*const sqlite3BuiltinExtensions[])(sqlite3*) = {
+#ifdef SQLITE_ENABLE_FTS3
+  sqlite3Fts3Init,
+#endif
+#ifdef SQLITE_ENABLE_FTS5
+  sqlite3Fts5Init,
+#endif
+#if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
+  sqlite3IcuInit,
+#endif
+#ifdef SQLITE_ENABLE_RTREE
+  sqlite3RtreeInit,
+#endif
+#ifdef SQLITE_ENABLE_DBPAGE_VTAB
+  sqlite3DbpageRegister,
+#endif
+#ifdef SQLITE_ENABLE_DBSTAT_VTAB
+  sqlite3DbstatRegister,
+#endif
+  sqlite3TestExtInit,
+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_JSON)
+  sqlite3JsonTableFunctions,
+#endif
+#ifdef SQLITE_ENABLE_STMTVTAB
+  sqlite3StmtVtabInit,
+#endif
+#ifdef SQLITE_ENABLE_BYTECODE_VTAB
+  sqlite3VdbeBytecodeVtabInit,
+#endif
+#ifdef SQLITE_EXTRA_AUTOEXT
+  SQLITE_EXTRA_AUTOEXT,
+#endif
+};
+
+#ifndef SQLITE_AMALGAMATION
+/* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
+** contains the text of SQLITE_VERSION macro.
+*/
+SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
+#endif
+
+/* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
+** a pointer to the to the sqlite3_version[] string constant.
+*/
+SQLITE_API const char *sqlite3_libversion(void){ return sqlite3_version; }
+
+/* IMPLEMENTATION-OF: R-25063-23286 The sqlite3_sourceid() function returns a
+** pointer to a string constant whose value is the same as the
+** SQLITE_SOURCE_ID C preprocessor macro. Except if SQLite is built using
+** an edited copy of the amalgamation, then the last four characters of
+** the hash might be different from SQLITE_SOURCE_ID.
+*/
+/* SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; } */
+
+/* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
+** returns an integer equal to SQLITE_VERSION_NUMBER.
+*/
+SQLITE_API int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
+
+/* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
+** zero if and only if SQLite was compiled with mutexing code omitted due to
+** the SQLITE_THREADSAFE compile-time option being set to 0.
+*/
+SQLITE_API int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
+
+/*
+** When compiling the test fixture or with debugging enabled (on Win32),
+** this variable being set to non-zero will cause OSTRACE macros to emit
+** extra diagnostic information.
+*/
+#ifdef SQLITE_HAVE_OS_TRACE
+# ifndef SQLITE_DEBUG_OS_TRACE
+#   define SQLITE_DEBUG_OS_TRACE 0
+# endif
+  int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
+#endif
+
+#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
+/*
+** If the following function pointer is not NULL and if
+** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
+** I/O active are written using this function.  These messages
+** are intended for debugging activity only.
+*/
+SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
+#endif
+
+/*
+** If the following global variable points to a string which is the
+** name of a directory, then that directory will be used to store
+** temporary files.
+**
+** See also the "PRAGMA temp_store_directory" SQL command.
+*/
+SQLITE_API char *sqlite3_temp_directory = 0;
+
+/*
+** If the following global variable points to a string which is the
+** name of a directory, then that directory will be used to store
+** all database files specified with a relative pathname.
+**
+** See also the "PRAGMA data_store_directory" SQL command.
+*/
+SQLITE_API char *sqlite3_data_directory = 0;
+
+/*
+** Initialize SQLite.
+**
+** This routine must be called to initialize the memory allocation,
+** VFS, and mutex subsystems prior to doing any serious work with
+** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
+** this routine will be called automatically by key routines such as
+** sqlite3_open().
+**
+** This routine is a no-op except on its very first call for the process,
+** or for the first call after a call to sqlite3_shutdown.
+**
+** The first thread to call this routine runs the initialization to
+** completion.  If subsequent threads call this routine before the first
+** thread has finished the initialization process, then the subsequent
+** threads must block until the first thread finishes with the initialization.
+**
+** The first thread might call this routine recursively.  Recursive
+** calls to this routine should not block, of course.  Otherwise the
+** initialization process would never complete.
+**
+** Let X be the first thread to enter this routine.  Let Y be some other
+** thread.  Then while the initial invocation of this routine by X is
+** incomplete, it is required that:
+**
+**    *  Calls to this routine from Y must block until the outer-most
+**       call by X completes.
+**
+**    *  Recursive calls to this routine from thread X return immediately
+**       without blocking.
+*/
+SQLITE_API int sqlite3_initialize(void){
+  MUTEX_LOGIC( sqlite3_mutex *pMainMtx; )      /* The main static mutex */
+  int rc;                                      /* Result code */
+#ifdef SQLITE_EXTRA_INIT
+  int bRunExtraInit = 0;                       /* Extra initialization needed */
+#endif
+
+#ifdef SQLITE_OMIT_WSD
+  rc = sqlite3_wsd_init(4096, 24);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+#endif
+
+  /* If the following assert() fails on some obscure processor/compiler
+  ** combination, the work-around is to set the correct pointer
+  ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
+  assert( SQLITE_PTRSIZE==sizeof(char*) );
+
+  /* If SQLite is already completely initialized, then this call
+  ** to sqlite3_initialize() should be a no-op.  But the initialization
+  ** must be complete.  So isInit must not be set until the very end
+  ** of this routine.
+  */
+  if( sqlite3GlobalConfig.isInit ){
+    sqlite3MemoryBarrier();
+    return SQLITE_OK;
+  }
+
+  /* Make sure the mutex subsystem is initialized.  If unable to
+  ** initialize the mutex subsystem, return early with the error.
+  ** If the system is so sick that we are unable to allocate a mutex,
+  ** there is not much SQLite is going to be able to do.
+  **
+  ** The mutex subsystem must take care of serializing its own
+  ** initialization.
+  */
+  rc = sqlite3MutexInit();
+  if( rc ) return rc;
+
+  /* Initialize the malloc() system and the recursive pInitMutex mutex.
+  ** This operation is protected by the STATIC_MAIN mutex.  Note that
+  ** MutexAlloc() is called for a static mutex prior to initializing the
+  ** malloc subsystem - this implies that the allocation of a static
+  ** mutex must not require support from the malloc subsystem.
+  */
+  MUTEX_LOGIC( pMainMtx = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  sqlite3_mutex_enter(pMainMtx);
+  sqlite3GlobalConfig.isMutexInit = 1;
+  if( !sqlite3GlobalConfig.isMallocInit ){
+    rc = sqlite3MallocInit();
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3GlobalConfig.isMallocInit = 1;
+    if( !sqlite3GlobalConfig.pInitMutex ){
+      sqlite3GlobalConfig.pInitMutex =
+           sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
+      if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
+        rc = SQLITE_NOMEM_BKPT;
+      }
+    }
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3GlobalConfig.nRefInitMutex++;
+  }
+  sqlite3_mutex_leave(pMainMtx);
+
+  /* If rc is not SQLITE_OK at this point, then either the malloc
+  ** subsystem could not be initialized or the system failed to allocate
+  ** the pInitMutex mutex. Return an error in either case.  */
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* Do the rest of the initialization under the recursive mutex so
+  ** that we will be able to handle recursive calls into
+  ** sqlite3_initialize().  The recursive calls normally come through
+  ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
+  ** recursive calls might also be possible.
+  **
+  ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
+  ** to the xInit method, so the xInit method need not be threadsafe.
+  **
+  ** The following mutex is what serializes access to the appdef pcache xInit
+  ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
+  ** call to sqlite3PcacheInitialize().
+  */
+  sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
+  if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
+    sqlite3GlobalConfig.inProgress = 1;
+#ifdef SQLITE_ENABLE_SQLLOG
+    {
+      extern void sqlite3_init_sqllog(void);
+      sqlite3_init_sqllog();
+    }
+#endif
+    memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
+    sqlite3RegisterBuiltinFunctions();
+    if( sqlite3GlobalConfig.isPCacheInit==0 ){
+      rc = sqlite3PcacheInitialize();
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3GlobalConfig.isPCacheInit = 1;
+      rc = sqlite3OsInit();
+    }
+#ifndef SQLITE_OMIT_DESERIALIZE
+    if( rc==SQLITE_OK ){
+      rc = sqlite3MemdbInit();
+    }
+#endif
+    if( rc==SQLITE_OK ){
+      sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
+          sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
+      sqlite3MemoryBarrier();
+      sqlite3GlobalConfig.isInit = 1;
+#ifdef SQLITE_EXTRA_INIT
+      bRunExtraInit = 1;
+#endif
+    }
+    sqlite3GlobalConfig.inProgress = 0;
+  }
+  sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
+
+  /* Go back under the static mutex and clean up the recursive
+  ** mutex to prevent a resource leak.
+  */
+  sqlite3_mutex_enter(pMainMtx);
+  sqlite3GlobalConfig.nRefInitMutex--;
+  if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
+    assert( sqlite3GlobalConfig.nRefInitMutex==0 );
+    sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
+    sqlite3GlobalConfig.pInitMutex = 0;
+  }
+  sqlite3_mutex_leave(pMainMtx);
+
+  /* The following is just a sanity check to make sure SQLite has
+  ** been compiled correctly.  It is important to run this code, but
+  ** we don't want to run it too often and soak up CPU cycles for no
+  ** reason.  So we run it once during initialization.
+  */
+#ifndef NDEBUG
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  /* This section of code's only "output" is via assert() statements. */
+  if( rc==SQLITE_OK ){
+    u64 x = (((u64)1)<<63)-1;
+    double y;
+    assert(sizeof(x)==8);
+    assert(sizeof(x)==sizeof(y));
+    memcpy(&y, &x, 8);
+    assert( sqlite3IsNaN(y) );
+  }
+#endif
+#endif
+
+  /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
+  ** compile-time option.
+  */
+#ifdef SQLITE_EXTRA_INIT
+  if( bRunExtraInit ){
+    int SQLITE_EXTRA_INIT(const char*);
+    rc = SQLITE_EXTRA_INIT(0);
+  }
+#endif
+  return rc;
+}
+
+/*
+** Undo the effects of sqlite3_initialize().  Must not be called while
+** there are outstanding database connections or memory allocations or
+** while any part of SQLite is otherwise in use in any thread.  This
+** routine is not threadsafe.  But it is safe to invoke this routine
+** on when SQLite is already shut down.  If SQLite is already shut down
+** when this routine is invoked, then this routine is a harmless no-op.
+*/
+SQLITE_API int sqlite3_shutdown(void){
+#ifdef SQLITE_OMIT_WSD
+  int rc = sqlite3_wsd_init(4096, 24);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+#endif
+
+  if( sqlite3GlobalConfig.isInit ){
+#ifdef SQLITE_EXTRA_SHUTDOWN
+    void SQLITE_EXTRA_SHUTDOWN(void);
+    SQLITE_EXTRA_SHUTDOWN();
+#endif
+    sqlite3_os_end();
+    sqlite3_reset_auto_extension();
+    sqlite3GlobalConfig.isInit = 0;
+  }
+  if( sqlite3GlobalConfig.isPCacheInit ){
+    sqlite3PcacheShutdown();
+    sqlite3GlobalConfig.isPCacheInit = 0;
+  }
+  if( sqlite3GlobalConfig.isMallocInit ){
+    sqlite3MallocEnd();
+    sqlite3GlobalConfig.isMallocInit = 0;
+
+#ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
+    /* The heap subsystem has now been shutdown and these values are supposed
+    ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
+    ** which would rely on that heap subsystem; therefore, make sure these
+    ** values cannot refer to heap memory that was just invalidated when the
+    ** heap subsystem was shutdown.  This is only done if the current call to
+    ** this function resulted in the heap subsystem actually being shutdown.
+    */
+    sqlite3_data_directory = 0;
+    sqlite3_temp_directory = 0;
+#endif
+  }
+  if( sqlite3GlobalConfig.isMutexInit ){
+    sqlite3MutexEnd();
+    sqlite3GlobalConfig.isMutexInit = 0;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** This API allows applications to modify the global configuration of
+** the SQLite library at run-time.
+**
+** This routine should only be called when there are no outstanding
+** database connections or memory allocations.  This routine is not
+** threadsafe.  Failure to heed these warnings can lead to unpredictable
+** behavior.
+*/
+SQLITE_API int sqlite3_config(int op, ...){
+  va_list ap;
+  int rc = SQLITE_OK;
+
+  /* sqlite3_config() normally returns SQLITE_MISUSE if it is invoked while
+  ** the SQLite library is in use.  Except, a few selected opcodes
+  ** are allowed.
+  */
+  if( sqlite3GlobalConfig.isInit ){
+    static const u64 mAnytimeConfigOption = 0
+       | MASKBIT64( SQLITE_CONFIG_LOG )
+       | MASKBIT64( SQLITE_CONFIG_PCACHE_HDRSZ )
+    ;
+    if( op<0 || op>63 || (MASKBIT64(op) & mAnytimeConfigOption)==0 ){
+      return SQLITE_MISUSE_BKPT;
+    }
+    testcase( op==SQLITE_CONFIG_LOG );
+    testcase( op==SQLITE_CONFIG_PCACHE_HDRSZ );
+  }
+
+  va_start(ap, op);
+  switch( op ){
+
+    /* Mutex configuration options are only available in a threadsafe
+    ** compile.
+    */
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
+    case SQLITE_CONFIG_SINGLETHREAD: {
+      /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
+      ** Single-thread. */
+      sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
+      sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
+      break;
+    }
+#endif
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
+    case SQLITE_CONFIG_MULTITHREAD: {
+      /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
+      ** Multi-thread. */
+      sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
+      sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
+      break;
+    }
+#endif
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
+    case SQLITE_CONFIG_SERIALIZED: {
+      /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
+      ** Serialized. */
+      sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
+      sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
+      break;
+    }
+#endif
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
+    case SQLITE_CONFIG_MUTEX: {
+      /* Specify an alternative mutex implementation */
+      sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
+      break;
+    }
+#endif
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
+    case SQLITE_CONFIG_GETMUTEX: {
+      /* Retrieve the current mutex implementation */
+      *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
+      break;
+    }
+#endif
+
+    case SQLITE_CONFIG_MALLOC: {
+      /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
+      ** single argument which is a pointer to an instance of the
+      ** sqlite3_mem_methods structure. The argument specifies alternative
+      ** low-level memory allocation routines to be used in place of the memory
+      ** allocation routines built into SQLite. */
+      sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
+      break;
+    }
+    case SQLITE_CONFIG_GETMALLOC: {
+      /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
+      ** single argument which is a pointer to an instance of the
+      ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
+      ** filled with the currently defined memory allocation routines. */
+      if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
+      *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
+      break;
+    }
+    case SQLITE_CONFIG_MEMSTATUS: {
+      assert( !sqlite3GlobalConfig.isInit );  /* Cannot change at runtime */
+      /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
+      ** single argument of type int, interpreted as a boolean, which enables
+      ** or disables the collection of memory allocation statistics. */
+      sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
+      break;
+    }
+    case SQLITE_CONFIG_SMALL_MALLOC: {
+      sqlite3GlobalConfig.bSmallMalloc = va_arg(ap, int);
+      break;
+    }
+    case SQLITE_CONFIG_PAGECACHE: {
+      /* EVIDENCE-OF: R-18761-36601 There are three arguments to
+      ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
+      ** the size of each page cache line (sz), and the number of cache lines
+      ** (N). */
+      sqlite3GlobalConfig.pPage = va_arg(ap, void*);
+      sqlite3GlobalConfig.szPage = va_arg(ap, int);
+      sqlite3GlobalConfig.nPage = va_arg(ap, int);
+      break;
+    }
+    case SQLITE_CONFIG_PCACHE_HDRSZ: {
+      /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
+      ** a single parameter which is a pointer to an integer and writes into
+      ** that integer the number of extra bytes per page required for each page
+      ** in SQLITE_CONFIG_PAGECACHE. */
+      *va_arg(ap, int*) =
+          sqlite3HeaderSizeBtree() +
+          sqlite3HeaderSizePcache() +
+          sqlite3HeaderSizePcache1();
+      break;
+    }
+
+    case SQLITE_CONFIG_PCACHE: {
+      /* no-op */
+      break;
+    }
+    case SQLITE_CONFIG_GETPCACHE: {
+      /* now an error */
+      rc = SQLITE_ERROR;
+      break;
+    }
+
+    case SQLITE_CONFIG_PCACHE2: {
+      /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
+      ** single argument which is a pointer to an sqlite3_pcache_methods2
+      ** object. This object specifies the interface to a custom page cache
+      ** implementation. */
+      sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
+      break;
+    }
+    case SQLITE_CONFIG_GETPCACHE2: {
+      /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
+      ** single argument which is a pointer to an sqlite3_pcache_methods2
+      ** object. SQLite copies of the current page cache implementation into
+      ** that object. */
+      if( sqlite3GlobalConfig.pcache2.xInit==0 ){
+        sqlite3PCacheSetDefault();
+      }
+      *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
+      break;
+    }
+
+/* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
+** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
+** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
+#if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
+    case SQLITE_CONFIG_HEAP: {
+      /* EVIDENCE-OF: R-19854-42126 There are three arguments to
+      ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
+      ** number of bytes in the memory buffer, and the minimum allocation size.
+      */
+      sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
+      sqlite3GlobalConfig.nHeap = va_arg(ap, int);
+      sqlite3GlobalConfig.mnReq = va_arg(ap, int);
+
+      if( sqlite3GlobalConfig.mnReq<1 ){
+        sqlite3GlobalConfig.mnReq = 1;
+      }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
+        /* cap min request size at 2^12 */
+        sqlite3GlobalConfig.mnReq = (1<<12);
+      }
+
+      if( sqlite3GlobalConfig.pHeap==0 ){
+        /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
+        ** is NULL, then SQLite reverts to using its default memory allocator
+        ** (the system malloc() implementation), undoing any prior invocation of
+        ** SQLITE_CONFIG_MALLOC.
+        **
+        ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
+        ** revert to its default implementation when sqlite3_initialize() is run
+        */
+        memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
+      }else{
+        /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
+        ** alternative memory allocator is engaged to handle all of SQLites
+        ** memory allocation needs. */
+#ifdef SQLITE_ENABLE_MEMSYS3
+        sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS5
+        sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
+#endif
+      }
+      break;
+    }
+#endif
+
+    case SQLITE_CONFIG_LOOKASIDE: {
+      sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
+      sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
+      break;
+    }
+
+    /* Record a pointer to the logger function and its first argument.
+    ** The default is NULL.  Logging is disabled if the function pointer is
+    ** NULL.
+    */
+    case SQLITE_CONFIG_LOG: {
+      /* MSVC is picky about pulling func ptrs from va lists.
+      ** http://support.microsoft.com/kb/47961
+      ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
+      */
+      typedef void(*LOGFUNC_t)(void*,int,const char*);
+      LOGFUNC_t xLog = va_arg(ap, LOGFUNC_t);
+      void *pLogArg = va_arg(ap, void*);
+      AtomicStore(&sqlite3GlobalConfig.xLog, xLog);
+      AtomicStore(&sqlite3GlobalConfig.pLogArg, pLogArg);
+      break;
+    }
+
+    /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
+    ** can be changed at start-time using the
+    ** sqlite3_config(SQLITE_CONFIG_URI,1) or
+    ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
+    */
+    case SQLITE_CONFIG_URI: {
+      /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
+      ** argument of type int. If non-zero, then URI handling is globally
+      ** enabled. If the parameter is zero, then URI handling is globally
+      ** disabled. */
+      int bOpenUri = va_arg(ap, int);
+      AtomicStore(&sqlite3GlobalConfig.bOpenUri, bOpenUri);
+      break;
+    }
+
+    case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
+      /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
+      ** option takes a single integer argument which is interpreted as a
+      ** boolean in order to enable or disable the use of covering indices for
+      ** full table scans in the query optimizer. */
+      sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
+      break;
+    }
+
+#ifdef SQLITE_ENABLE_SQLLOG
+    case SQLITE_CONFIG_SQLLOG: {
+      typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
+      sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
+      sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
+      break;
+    }
+#endif
+
+    case SQLITE_CONFIG_MMAP_SIZE: {
+      /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
+      ** integer (sqlite3_int64) values that are the default mmap size limit
+      ** (the default setting for PRAGMA mmap_size) and the maximum allowed
+      ** mmap size limit. */
+      sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
+      sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
+      /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
+      ** negative, then that argument is changed to its compile-time default.
+      **
+      ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
+      ** silently truncated if necessary so that it does not exceed the
+      ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
+      ** compile-time option.
+      */
+      if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
+        mxMmap = SQLITE_MAX_MMAP_SIZE;
+      }
+      if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
+      if( szMmap>mxMmap) szMmap = mxMmap;
+      sqlite3GlobalConfig.mxMmap = mxMmap;
+      sqlite3GlobalConfig.szMmap = szMmap;
+      break;
+    }
+
+#if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
+    case SQLITE_CONFIG_WIN32_HEAPSIZE: {
+      /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
+      ** unsigned integer value that specifies the maximum size of the created
+      ** heap. */
+      sqlite3GlobalConfig.nHeap = va_arg(ap, int);
+      break;
+    }
+#endif
+
+    case SQLITE_CONFIG_PMASZ: {
+      sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
+      break;
+    }
+
+    case SQLITE_CONFIG_STMTJRNL_SPILL: {
+      sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
+      break;
+    }
+
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    case SQLITE_CONFIG_SORTERREF_SIZE: {
+      int iVal = va_arg(ap, int);
+      if( iVal<0 ){
+        iVal = SQLITE_DEFAULT_SORTERREF_SIZE;
+      }
+      sqlite3GlobalConfig.szSorterRef = (u32)iVal;
+      break;
+    }
+#endif /* SQLITE_ENABLE_SORTER_REFERENCES */
+
+#ifndef SQLITE_OMIT_DESERIALIZE
+    case SQLITE_CONFIG_MEMDB_MAXSIZE: {
+      sqlite3GlobalConfig.mxMemdbSize = va_arg(ap, sqlite3_int64);
+      break;
+    }
+#endif /* SQLITE_OMIT_DESERIALIZE */
+
+    case SQLITE_CONFIG_ROWID_IN_VIEW: {
+      int *pVal = va_arg(ap,int*);
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+      if( 0==*pVal ) sqlite3GlobalConfig.mNoVisibleRowid = TF_NoVisibleRowid;
+      if( 1==*pVal ) sqlite3GlobalConfig.mNoVisibleRowid = 0;
+      *pVal = (sqlite3GlobalConfig.mNoVisibleRowid==0);
+#else
+      *pVal = 0;
+#endif
+      break;
+    }
+
+    default: {
+      rc = SQLITE_ERROR;
+      break;
+    }
+  }
+  va_end(ap);
+  return rc;
+}
+
+/*
+** Set up the lookaside buffers for a database connection.
+** Return SQLITE_OK on success.
+** If lookaside is already active, return SQLITE_BUSY.
+**
+** The sz parameter is the number of bytes in each lookaside slot.
+** The cnt parameter is the number of slots.  If pStart is NULL the
+** space for the lookaside memory is obtained from sqlite3_malloc().
+** If pStart is not NULL then it is sz*cnt bytes of memory to use for
+** the lookaside memory.
+*/
+static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
+#ifndef SQLITE_OMIT_LOOKASIDE
+  void *pStart;
+  sqlite3_int64 szAlloc;
+  int nBig;   /* Number of full-size slots */
+  int nSm;    /* Number smaller LOOKASIDE_SMALL-byte slots */
+
+  if( sqlite3LookasideUsed(db,0)>0 ){
+    return SQLITE_BUSY;
+  }
+  /* Free any existing lookaside buffer for this handle before
+  ** allocating a new one so we don't have to have space for
+  ** both at the same time.
+  */
+  if( db->lookaside.bMalloced ){
+    sqlite3_free(db->lookaside.pStart);
+  }
+  /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
+  ** than a pointer to be useful.
+  */
+  sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
+  if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
+  if( sz>65528 ) sz = 65528;
+  if( cnt<0 ) cnt = 0;
+  szAlloc = (i64)sz*(i64)cnt;
+  if( sz==0 || cnt==0 ){
+    sz = 0;
+    pStart = 0;
+  }else if( pBuf==0 ){
+    sqlite3BeginBenignMalloc();
+    pStart = sqlite3Malloc( szAlloc );  /* IMP: R-61949-35727 */
+    sqlite3EndBenignMalloc();
+    if( pStart ) szAlloc = sqlite3MallocSize(pStart);
+  }else{
+    pStart = pBuf;
+  }
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  if( sz>=LOOKASIDE_SMALL*3 ){
+    nBig = szAlloc/(3*LOOKASIDE_SMALL+sz);
+    nSm = (szAlloc - (i64)sz*(i64)nBig)/LOOKASIDE_SMALL;
+  }else if( sz>=LOOKASIDE_SMALL*2 ){
+    nBig = szAlloc/(LOOKASIDE_SMALL+sz);
+    nSm = (szAlloc - (i64)sz*(i64)nBig)/LOOKASIDE_SMALL;
+  }else
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+  if( sz>0 ){
+    nBig = szAlloc/sz;
+    nSm = 0;
+  }else{
+    nBig = nSm = 0;
+  }
+  db->lookaside.pStart = pStart;
+  db->lookaside.pInit = 0;
+  db->lookaside.pFree = 0;
+  db->lookaside.sz = (u16)sz;
+  db->lookaside.szTrue = (u16)sz;
+  if( pStart ){
+    int i;
+    LookasideSlot *p;
+    assert( sz > (int)sizeof(LookasideSlot*) );
+    p = (LookasideSlot*)pStart;
+    for(i=0; i<nBig; i++){
+      p->pNext = db->lookaside.pInit;
+      db->lookaside.pInit = p;
+      p = (LookasideSlot*)&((u8*)p)[sz];
+    }
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+    db->lookaside.pSmallInit = 0;
+    db->lookaside.pSmallFree = 0;
+    db->lookaside.pMiddle = p;
+    for(i=0; i<nSm; i++){
+      p->pNext = db->lookaside.pSmallInit;
+      db->lookaside.pSmallInit = p;
+      p = (LookasideSlot*)&((u8*)p)[LOOKASIDE_SMALL];
+    }
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+    assert( ((uptr)p)<=szAlloc + (uptr)pStart );
+    db->lookaside.pEnd = p;
+    db->lookaside.bDisable = 0;
+    db->lookaside.bMalloced = pBuf==0 ?1:0;
+    db->lookaside.nSlot = nBig+nSm;
+  }else{
+    db->lookaside.pStart = 0;
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+    db->lookaside.pSmallInit = 0;
+    db->lookaside.pSmallFree = 0;
+    db->lookaside.pMiddle = 0;
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+    db->lookaside.pEnd = 0;
+    db->lookaside.bDisable = 1;
+    db->lookaside.sz = 0;
+    db->lookaside.bMalloced = 0;
+    db->lookaside.nSlot = 0;
+  }
+  db->lookaside.pTrueEnd = db->lookaside.pEnd;
+  assert( sqlite3LookasideUsed(db,0)==0 );
+#endif /* SQLITE_OMIT_LOOKASIDE */
+  return SQLITE_OK;
+}
+
+/*
+** Return the mutex associated with a database connection.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->mutex;
+}
+
+/*
+** Free up as much memory as we can from the given database
+** connection.
+*/
+SQLITE_API int sqlite3_db_release_memory(sqlite3 *db){
+  int i;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  for(i=0; i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      Pager *pPager = sqlite3BtreePager(pBt);
+      sqlite3PagerShrink(pPager);
+    }
+  }
+  sqlite3BtreeLeaveAll(db);
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Flush any dirty pages in the pager-cache for any attached database
+** to disk.
+*/
+SQLITE_API int sqlite3_db_cacheflush(sqlite3 *db){
+  int i;
+  int rc = SQLITE_OK;
+  int bSeenBusy = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt && sqlite3BtreeTxnState(pBt)==SQLITE_TXN_WRITE ){
+      Pager *pPager = sqlite3BtreePager(pBt);
+      rc = sqlite3PagerFlush(pPager);
+      if( rc==SQLITE_BUSY ){
+        bSeenBusy = 1;
+        rc = SQLITE_OK;
+      }
+    }
+  }
+  sqlite3BtreeLeaveAll(db);
+  sqlite3_mutex_leave(db->mutex);
+  return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
+}
+
+/*
+** Configuration settings for an individual database connection
+*/
+SQLITE_API int sqlite3_db_config(sqlite3 *db, int op, ...){
+  va_list ap;
+  int rc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  va_start(ap, op);
+  switch( op ){
+    case SQLITE_DBCONFIG_MAINDBNAME: {
+      /* IMP: R-06824-28531 */
+      /* IMP: R-36257-52125 */
+      db->aDb[0].zDbSName = va_arg(ap,char*);
+      rc = SQLITE_OK;
+      break;
+    }
+    case SQLITE_DBCONFIG_LOOKASIDE: {
+      void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
+      int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
+      int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
+      rc = setupLookaside(db, pBuf, sz, cnt);
+      break;
+    }
+    default: {
+      static const struct {
+        int op;      /* The opcode */
+        u64 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
+      } aFlagOp[] = {
+        { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
+        { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
+        { SQLITE_DBCONFIG_ENABLE_VIEW,           SQLITE_EnableView     },
+        { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
+        { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
+        { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
+        { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
+        { SQLITE_DBCONFIG_TRIGGER_EQP,           SQLITE_TriggerEQP     },
+        { SQLITE_DBCONFIG_RESET_DATABASE,        SQLITE_ResetDatabase  },
+        { SQLITE_DBCONFIG_DEFENSIVE,             SQLITE_Defensive      },
+        { SQLITE_DBCONFIG_WRITABLE_SCHEMA,       SQLITE_WriteSchema|
+                                                 SQLITE_NoSchemaError  },
+        { SQLITE_DBCONFIG_LEGACY_ALTER_TABLE,    SQLITE_LegacyAlter    },
+        { SQLITE_DBCONFIG_DQS_DDL,               SQLITE_DqsDDL         },
+        { SQLITE_DBCONFIG_DQS_DML,               SQLITE_DqsDML         },
+        { SQLITE_DBCONFIG_LEGACY_FILE_FORMAT,    SQLITE_LegacyFileFmt  },
+        { SQLITE_DBCONFIG_TRUSTED_SCHEMA,        SQLITE_TrustedSchema  },
+        { SQLITE_DBCONFIG_STMT_SCANSTATUS,       SQLITE_StmtScanStatus },
+        { SQLITE_DBCONFIG_REVERSE_SCANORDER,     SQLITE_ReverseOrder   },
+        { SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE,  SQLITE_AttachCreate   },
+        { SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE,   SQLITE_AttachWrite    },
+        { SQLITE_DBCONFIG_ENABLE_COMMENTS,       SQLITE_Comments       },
+      };
+      unsigned int i;
+      rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
+      for(i=0; i<ArraySize(aFlagOp); i++){
+        if( aFlagOp[i].op==op ){
+          int onoff = va_arg(ap, int);
+          int *pRes = va_arg(ap, int*);
+          u64 oldFlags = db->flags;
+          if( onoff>0 ){
+            db->flags |= aFlagOp[i].mask;
+          }else if( onoff==0 ){
+            db->flags &= ~(u64)aFlagOp[i].mask;
+          }
+          if( oldFlags!=db->flags ){
+            sqlite3ExpirePreparedStatements(db, 0);
+          }
+          if( pRes ){
+            *pRes = (db->flags & aFlagOp[i].mask)!=0;
+          }
+          rc = SQLITE_OK;
+          break;
+        }
+      }
+      break;
+    }
+  }
+  va_end(ap);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** This is the default collating function named "BINARY" which is always
+** available.
+*/
+static int binCollFunc(
+  void *NotUsed,
+  int nKey1, const void *pKey1,
+  int nKey2, const void *pKey2
+){
+  int rc, n;
+  UNUSED_PARAMETER(NotUsed);
+  n = nKey1<nKey2 ? nKey1 : nKey2;
+  /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
+  ** strings byte by byte using the memcmp() function from the standard C
+  ** library. */
+  assert( pKey1 && pKey2 );
+  rc = memcmp(pKey1, pKey2, n);
+  if( rc==0 ){
+    rc = nKey1 - nKey2;
+  }
+  return rc;
+}
+
+/*
+** This is the collating function named "RTRIM" which is always
+** available.  Ignore trailing spaces.
+*/
+static int rtrimCollFunc(
+  void *pUser,
+  int nKey1, const void *pKey1,
+  int nKey2, const void *pKey2
+){
+  const u8 *pK1 = (const u8*)pKey1;
+  const u8 *pK2 = (const u8*)pKey2;
+  while( nKey1 && pK1[nKey1-1]==' ' ) nKey1--;
+  while( nKey2 && pK2[nKey2-1]==' ' ) nKey2--;
+  return binCollFunc(pUser, nKey1, pKey1, nKey2, pKey2);
+}
+
+/*
+** Return true if CollSeq is the default built-in BINARY.
+*/
+SQLITE_PRIVATE int sqlite3IsBinary(const CollSeq *p){
+  assert( p==0 || p->xCmp!=binCollFunc || strcmp(p->zName,"BINARY")==0 );
+  return p==0 || p->xCmp==binCollFunc;
+}
+
+/*
+** Another built-in collating sequence: NOCASE.
+**
+** This collating sequence is intended to be used for "case independent
+** comparison". SQLite's knowledge of upper and lower case equivalents
+** extends only to the 26 characters used in the English language.
+**
+** At the moment there is only a UTF-8 implementation.
+*/
+static int nocaseCollatingFunc(
+  void *NotUsed,
+  int nKey1, const void *pKey1,
+  int nKey2, const void *pKey2
+){
+  int r = sqlite3StrNICmp(
+      (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
+  UNUSED_PARAMETER(NotUsed);
+  if( 0==r ){
+    r = nKey1-nKey2;
+  }
+  return r;
+}
+
+/*
+** Return the ROWID of the most recent insert
+*/
+SQLITE_API sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->lastRowid;
+}
+
+/*
+** Set the value returned by the sqlite3_last_insert_rowid() API function.
+*/
+SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->lastRowid = iRowid;
+  sqlite3_mutex_leave(db->mutex);
+}
+
+/*
+** Return the number of changes in the most recent call to sqlite3_exec().
+*/
+SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->nChange;
+}
+SQLITE_API int sqlite3_changes(sqlite3 *db){
+  return (int)sqlite3_changes64(db);
+}
+
+/*
+** Return the number of changes since the database handle was opened.
+*/
+SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->nTotalChange;
+}
+SQLITE_API int sqlite3_total_changes(sqlite3 *db){
+  return (int)sqlite3_total_changes64(db);
+}
+
+/*
+** Close all open savepoints. This function only manipulates fields of the
+** database handle object, it does not close any savepoints that may be open
+** at the b-tree/pager level.
+*/
+SQLITE_PRIVATE void sqlite3CloseSavepoints(sqlite3 *db){
+  while( db->pSavepoint ){
+    Savepoint *pTmp = db->pSavepoint;
+    db->pSavepoint = pTmp->pNext;
+    sqlite3DbFree(db, pTmp);
+  }
+  db->nSavepoint = 0;
+  db->nStatement = 0;
+  db->isTransactionSavepoint = 0;
+}
+
+/*
+** Invoke the destructor function associated with FuncDef p, if any. Except,
+** if this is not the last copy of the function, do not invoke it. Multiple
+** copies of a single function are created when create_function() is called
+** with SQLITE_ANY as the encoding.
+*/
+static void functionDestroy(sqlite3 *db, FuncDef *p){
+  FuncDestructor *pDestructor;
+  assert( (p->funcFlags & SQLITE_FUNC_BUILTIN)==0 );
+  pDestructor = p->u.pDestructor;
+  if( pDestructor ){
+    pDestructor->nRef--;
+    if( pDestructor->nRef==0 ){
+      pDestructor->xDestroy(pDestructor->pUserData);
+      sqlite3DbFree(db, pDestructor);
+    }
+  }
+}
+
+/*
+** Disconnect all sqlite3_vtab objects that belong to database connection
+** db. This is called when db is being closed.
+*/
+static void disconnectAllVtab(sqlite3 *db){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  int i;
+  HashElem *p;
+  sqlite3BtreeEnterAll(db);
+  for(i=0; i<db->nDb; i++){
+    Schema *pSchema = db->aDb[i].pSchema;
+    if( pSchema ){
+      for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
+        Table *pTab = (Table *)sqliteHashData(p);
+        if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
+      }
+    }
+  }
+  for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
+    Module *pMod = (Module *)sqliteHashData(p);
+    if( pMod->pEpoTab ){
+      sqlite3VtabDisconnect(db, pMod->pEpoTab);
+    }
+  }
+  sqlite3VtabUnlockList(db);
+  sqlite3BtreeLeaveAll(db);
+#else
+  UNUSED_PARAMETER(db);
+#endif
+}
+
+/*
+** Return TRUE if database connection db has unfinalized prepared
+** statements or unfinished sqlite3_backup objects.
+*/
+static int connectionIsBusy(sqlite3 *db){
+  int j;
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( db->pVdbe ) return 1;
+  for(j=0; j<db->nDb; j++){
+    Btree *pBt = db->aDb[j].pBt;
+    if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Close an existing SQLite database
+*/
+static int sqlite3Close(sqlite3 *db, int forceZombie){
+  if( !db ){
+    /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
+    ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
+    return SQLITE_OK;
+  }
+  if( !sqlite3SafetyCheckSickOrOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  sqlite3_mutex_enter(db->mutex);
+  if( db->mTrace & SQLITE_TRACE_CLOSE ){
+    db->trace.xV2(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
+  }
+
+  /* Force xDisconnect calls on all virtual tables */
+  disconnectAllVtab(db);
+
+  /* If a transaction is open, the disconnectAllVtab() call above
+  ** will not have called the xDisconnect() method on any virtual
+  ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
+  ** call will do so. We need to do this before the check for active
+  ** SQL statements below, as the v-table implementation may be storing
+  ** some prepared statements internally.
+  */
+  sqlite3VtabRollback(db);
+
+  /* Legacy behavior (sqlite3_close() behavior) is to return
+  ** SQLITE_BUSY if the connection can not be closed immediately.
+  */
+  if( !forceZombie && connectionIsBusy(db) ){
+    sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
+       "statements or unfinished backups");
+    sqlite3_mutex_leave(db->mutex);
+    return SQLITE_BUSY;
+  }
+
+#ifdef SQLITE_ENABLE_SQLLOG
+  if( sqlite3GlobalConfig.xSqllog ){
+    /* Closing the handle. Fourth parameter is passed the value 2. */
+    sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
+  }
+#endif
+
+  while( db->pDbData ){
+    DbClientData *p = db->pDbData;
+    db->pDbData = p->pNext;
+    assert( p->pData!=0 );
+    if( p->xDestructor ) p->xDestructor(p->pData);
+    sqlite3_free(p);
+  }
+
+  /* Convert the connection into a zombie and then close it.
+  */
+  db->eOpenState = SQLITE_STATE_ZOMBIE;
+  sqlite3LeaveMutexAndCloseZombie(db);
+  return SQLITE_OK;
+}
+
+/*
+** Return the transaction state for a single databse, or the maximum
+** transaction state over all attached databases if zSchema is null.
+*/
+SQLITE_API int sqlite3_txn_state(sqlite3 *db, const char *zSchema){
+  int iDb, nDb;
+  int iTxn = -1;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return -1;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( zSchema ){
+    nDb = iDb = sqlite3FindDbName(db, zSchema);
+    if( iDb<0 ) nDb--;
+  }else{
+    iDb = 0;
+    nDb = db->nDb-1;
+  }
+  for(; iDb<=nDb; iDb++){
+    Btree *pBt = db->aDb[iDb].pBt;
+    int x = pBt!=0 ? sqlite3BtreeTxnState(pBt) : SQLITE_TXN_NONE;
+    if( x>iTxn ) iTxn = x;
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return iTxn;
+}
+
+/*
+** Two variations on the public interface for closing a database
+** connection. The sqlite3_close() version returns SQLITE_BUSY and
+** leaves the connection open if there are unfinalized prepared
+** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
+** version forces the connection to become a zombie if there are
+** unclosed resources, and arranges for deallocation when the last
+** prepare statement or sqlite3_backup closes.
+*/
+SQLITE_API int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
+SQLITE_API int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
+
+
+/*
+** Close the mutex on database connection db.
+**
+** Furthermore, if database connection db is a zombie (meaning that there
+** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
+** every sqlite3_stmt has now been finalized and every sqlite3_backup has
+** finished, then free all resources.
+*/
+SQLITE_PRIVATE void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
+  HashElem *i;                    /* Hash table iterator */
+  int j;
+
+  /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
+  ** or if the connection has not yet been closed by sqlite3_close_v2(),
+  ** then just leave the mutex and return.
+  */
+  if( db->eOpenState!=SQLITE_STATE_ZOMBIE || connectionIsBusy(db) ){
+    sqlite3_mutex_leave(db->mutex);
+    return;
+  }
+
+  /* If we reach this point, it means that the database connection has
+  ** closed all sqlite3_stmt and sqlite3_backup objects and has been
+  ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
+  ** go ahead and free all resources.
+  */
+
+  /* If a transaction is open, roll it back. This also ensures that if
+  ** any database schemas have been modified by an uncommitted transaction
+  ** they are reset. And that the required b-tree mutex is held to make
+  ** the pager rollback and schema reset an atomic operation. */
+  sqlite3RollbackAll(db, SQLITE_OK);
+
+  /* Free any outstanding Savepoint structures. */
+  sqlite3CloseSavepoints(db);
+
+  /* Close all database connections */
+  for(j=0; j<db->nDb; j++){
+    struct Db *pDb = &db->aDb[j];
+    if( pDb->pBt ){
+      sqlite3BtreeClose(pDb->pBt);
+      pDb->pBt = 0;
+      if( j!=1 ){
+        pDb->pSchema = 0;
+      }
+    }
+  }
+  /* Clear the TEMP schema separately and last */
+  if( db->aDb[1].pSchema ){
+    sqlite3SchemaClear(db->aDb[1].pSchema);
+  }
+  sqlite3VtabUnlockList(db);
+
+  /* Free up the array of auxiliary databases */
+  sqlite3CollapseDatabaseArray(db);
+  assert( db->nDb<=2 );
+  assert( db->aDb==db->aDbStatic );
+
+  /* Tell the code in notify.c that the connection no longer holds any
+  ** locks and does not require any further unlock-notify callbacks.
+  */
+  sqlite3ConnectionClosed(db);
+
+  for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
+    FuncDef *pNext, *p;
+    p = sqliteHashData(i);
+    do{
+      functionDestroy(db, p);
+      pNext = p->pNext;
+      sqlite3DbFree(db, p);
+      p = pNext;
+    }while( p );
+  }
+  sqlite3HashClear(&db->aFunc);
+  for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
+    CollSeq *pColl = (CollSeq *)sqliteHashData(i);
+    /* Invoke any destructors registered for collation sequence user data. */
+    for(j=0; j<3; j++){
+      if( pColl[j].xDel ){
+        pColl[j].xDel(pColl[j].pUser);
+      }
+    }
+    sqlite3DbFree(db, pColl);
+  }
+  sqlite3HashClear(&db->aCollSeq);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
+    Module *pMod = (Module *)sqliteHashData(i);
+    sqlite3VtabEponymousTableClear(db, pMod);
+    sqlite3VtabModuleUnref(db, pMod);
+  }
+  sqlite3HashClear(&db->aModule);
+#endif
+
+  sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
+  sqlite3ValueFree(db->pErr);
+  sqlite3CloseExtensions(db);
+
+  db->eOpenState = SQLITE_STATE_ERROR;
+
+  /* The temp-database schema is allocated differently from the other schema
+  ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
+  ** So it needs to be freed here. Todo: Why not roll the temp schema into
+  ** the same sqliteMalloc() as the one that allocates the database
+  ** structure?
+  */
+  sqlite3DbFree(db, db->aDb[1].pSchema);
+  if( db->xAutovacDestr ){
+    db->xAutovacDestr(db->pAutovacPagesArg);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  db->eOpenState = SQLITE_STATE_CLOSED;
+  sqlite3_mutex_free(db->mutex);
+  assert( sqlite3LookasideUsed(db,0)==0 );
+  if( db->lookaside.bMalloced ){
+    sqlite3_free(db->lookaside.pStart);
+  }
+  sqlite3_free(db);
+}
+
+/*
+** Rollback all database files.  If tripCode is not SQLITE_OK, then
+** any write cursors are invalidated ("tripped" - as in "tripping a circuit
+** breaker") and made to return tripCode if there are any further
+** attempts to use that cursor.  Read cursors remain open and valid
+** but are "saved" in case the table pages are moved around.
+*/
+SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3 *db, int tripCode){
+  int i;
+  int inTrans = 0;
+  int schemaChange;
+  assert( sqlite3_mutex_held(db->mutex) );
+  sqlite3BeginBenignMalloc();
+
+  /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
+  ** This is important in case the transaction being rolled back has
+  ** modified the database schema. If the b-tree mutexes are not taken
+  ** here, then another shared-cache connection might sneak in between
+  ** the database rollback and schema reset, which can cause false
+  ** corruption reports in some cases.  */
+  sqlite3BtreeEnterAll(db);
+  schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;
+
+  for(i=0; i<db->nDb; i++){
+    Btree *p = db->aDb[i].pBt;
+    if( p ){
+      if( sqlite3BtreeTxnState(p)==SQLITE_TXN_WRITE ){
+        inTrans = 1;
+      }
+      sqlite3BtreeRollback(p, tripCode, !schemaChange);
+    }
+  }
+  sqlite3VtabRollback(db);
+  sqlite3EndBenignMalloc();
+
+  if( schemaChange ){
+    sqlite3ExpirePreparedStatements(db, 0);
+    sqlite3ResetAllSchemasOfConnection(db);
+  }
+  sqlite3BtreeLeaveAll(db);
+
+  /* Any deferred constraint violations have now been resolved. */
+  db->nDeferredCons = 0;
+  db->nDeferredImmCons = 0;
+  db->flags &= ~(u64)(SQLITE_DeferFKs|SQLITE_CorruptRdOnly);
+
+  /* If one has been configured, invoke the rollback-hook callback */
+  if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
+    db->xRollbackCallback(db->pRollbackArg);
+  }
+}
+
+/*
+** Return a static string containing the name corresponding to the error code
+** specified in the argument.
+*/
+#if defined(SQLITE_NEED_ERR_NAME)
+SQLITE_PRIVATE const char *sqlite3ErrName(int rc){
+  const char *zName = 0;
+  int i, origRc = rc;
+  for(i=0; i<2 && zName==0; i++, rc &= 0xff){
+    switch( rc ){
+      case SQLITE_OK:                 zName = "SQLITE_OK";                break;
+      case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
+      case SQLITE_ERROR_SNAPSHOT:     zName = "SQLITE_ERROR_SNAPSHOT";    break;
+      case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
+      case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
+      case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
+      case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
+      case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
+      case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
+      case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
+      case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
+      case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
+      case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
+      case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
+      case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
+      case SQLITE_READONLY_CANTINIT:  zName = "SQLITE_READONLY_CANTINIT"; break;
+      case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
+      case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
+      case SQLITE_READONLY_DIRECTORY: zName = "SQLITE_READONLY_DIRECTORY";break;
+      case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
+      case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
+      case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
+      case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
+      case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
+      case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
+      case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
+      case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
+      case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
+      case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
+      case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
+      case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
+      case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
+      case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
+      case SQLITE_IOERR_CHECKRESERVEDLOCK:
+                                zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
+      case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
+      case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
+      case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
+      case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
+      case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
+      case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
+      case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
+      case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
+      case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
+      case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
+      case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
+      case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
+      case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
+      case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
+      case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
+      case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
+      case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
+      case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
+      case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
+      case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
+      case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
+      case SQLITE_CANTOPEN_SYMLINK:   zName = "SQLITE_CANTOPEN_SYMLINK";  break;
+      case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
+      case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
+      case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
+      case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
+      case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
+      case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
+      case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
+      case SQLITE_CONSTRAINT_FOREIGNKEY:
+                                zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
+      case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
+      case SQLITE_CONSTRAINT_PRIMARYKEY:
+                                zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
+      case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
+      case SQLITE_CONSTRAINT_COMMITHOOK:
+                                zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
+      case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
+      case SQLITE_CONSTRAINT_FUNCTION:
+                                zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
+      case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
+      case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
+      case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
+      case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
+      case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
+      case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
+      case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
+      case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
+      case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
+      case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
+      case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
+      case SQLITE_NOTICE_RECOVER_ROLLBACK:
+                                zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
+      case SQLITE_NOTICE_RBU:         zName = "SQLITE_NOTICE_RBU"; break;
+      case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
+      case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
+      case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
+    }
+  }
+  if( zName==0 ){
+    static char zBuf[50];
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
+    zName = zBuf;
+  }
+  return zName;
+}
+#endif
+
+/*
+** Return a static string that describes the kind of error specified in the
+** argument.
+*/
+SQLITE_PRIVATE const char *sqlite3ErrStr(int rc){
+  static const char* const aMsg[] = {
+    /* SQLITE_OK          */ "not an error",
+    /* SQLITE_ERROR       */ "SQL logic error",
+    /* SQLITE_INTERNAL    */ 0,
+    /* SQLITE_PERM        */ "access permission denied",
+    /* SQLITE_ABORT       */ "query aborted",
+    /* SQLITE_BUSY        */ "database is locked",
+    /* SQLITE_LOCKED      */ "database table is locked",
+    /* SQLITE_NOMEM       */ "out of memory",
+    /* SQLITE_READONLY    */ "attempt to write a readonly database",
+    /* SQLITE_INTERRUPT   */ "interrupted",
+    /* SQLITE_IOERR       */ "disk I/O error",
+    /* SQLITE_CORRUPT     */ "database disk image is malformed",
+    /* SQLITE_NOTFOUND    */ "unknown operation",
+    /* SQLITE_FULL        */ "database or disk is full",
+    /* SQLITE_CANTOPEN    */ "unable to open database file",
+    /* SQLITE_PROTOCOL    */ "locking protocol",
+    /* SQLITE_EMPTY       */ 0,
+    /* SQLITE_SCHEMA      */ "database schema has changed",
+    /* SQLITE_TOOBIG      */ "string or blob too big",
+    /* SQLITE_CONSTRAINT  */ "constraint failed",
+    /* SQLITE_MISMATCH    */ "datatype mismatch",
+    /* SQLITE_MISUSE      */ "bad parameter or other API misuse",
+#ifdef SQLITE_DISABLE_LFS
+    /* SQLITE_NOLFS       */ "large file support is disabled",
+#else
+    /* SQLITE_NOLFS       */ 0,
+#endif
+    /* SQLITE_AUTH        */ "authorization denied",
+    /* SQLITE_FORMAT      */ 0,
+    /* SQLITE_RANGE       */ "column index out of range",
+    /* SQLITE_NOTADB      */ "file is not a database",
+    /* SQLITE_NOTICE      */ "notification message",
+    /* SQLITE_WARNING     */ "warning message",
+  };
+  const char *zErr = "unknown error";
+  switch( rc ){
+    case SQLITE_ABORT_ROLLBACK: {
+      zErr = "abort due to ROLLBACK";
+      break;
+    }
+    case SQLITE_ROW: {
+      zErr = "another row available";
+      break;
+    }
+    case SQLITE_DONE: {
+      zErr = "no more rows available";
+      break;
+    }
+    default: {
+      rc &= 0xff;
+      if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
+        zErr = aMsg[rc];
+      }
+      break;
+    }
+  }
+  return zErr;
+}
+
+/*
+** This routine implements a busy callback that sleeps and tries
+** again until a timeout value is reached.  The timeout value is
+** an integer number of milliseconds passed in as the first
+** argument.
+**
+** Return non-zero to retry the lock.  Return zero to stop trying
+** and cause SQLite to return SQLITE_BUSY.
+*/
+static int sqliteDefaultBusyCallback(
+  void *ptr,               /* Database connection */
+  int count                /* Number of times table has been busy */
+){
+#if SQLITE_OS_WIN || !defined(HAVE_NANOSLEEP) || HAVE_NANOSLEEP
+  /* This case is for systems that have support for sleeping for fractions of
+  ** a second.  Examples:  All windows systems, unix systems with nanosleep() */
+  static const u8 delays[] =
+     { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
+  static const u8 totals[] =
+     { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
+# define NDELAY ArraySize(delays)
+  sqlite3 *db = (sqlite3 *)ptr;
+  int tmout = db->busyTimeout;
+  int delay, prior;
+
+  assert( count>=0 );
+  if( count < NDELAY ){
+    delay = delays[count];
+    prior = totals[count];
+  }else{
+    delay = delays[NDELAY-1];
+    prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
+  }
+  if( prior + delay > tmout ){
+    delay = tmout - prior;
+    if( delay<=0 ) return 0;
+  }
+  sqlite3OsSleep(db->pVfs, delay*1000);
+  return 1;
+#else
+  /* This case for unix systems that lack usleep() support.  Sleeping
+  ** must be done in increments of whole seconds */
+  sqlite3 *db = (sqlite3 *)ptr;
+  int tmout = ((sqlite3 *)ptr)->busyTimeout;
+  if( (count+1)*1000 > tmout ){
+    return 0;
+  }
+  sqlite3OsSleep(db->pVfs, 1000000);
+  return 1;
+#endif
+}
+
+/*
+** Invoke the given busy handler.
+**
+** This routine is called when an operation failed to acquire a
+** lock on VFS file pFile.
+**
+** If this routine returns non-zero, the lock is retried.  If it
+** returns 0, the operation aborts with an SQLITE_BUSY error.
+*/
+SQLITE_PRIVATE int sqlite3InvokeBusyHandler(BusyHandler *p){
+  int rc;
+  if( p->xBusyHandler==0 || p->nBusy<0 ) return 0;
+  rc = p->xBusyHandler(p->pBusyArg, p->nBusy);
+  if( rc==0 ){
+    p->nBusy = -1;
+  }else{
+    p->nBusy++;
+  }
+  return rc;
+}
+
+/*
+** This routine sets the busy callback for an Sqlite database to the
+** given callback function with the given argument.
+*/
+SQLITE_API int sqlite3_busy_handler(
+  sqlite3 *db,
+  int (*xBusy)(void*,int),
+  void *pArg
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->busyHandler.xBusyHandler = xBusy;
+  db->busyHandler.pBusyArg = pArg;
+  db->busyHandler.nBusy = 0;
+  db->busyTimeout = 0;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+/*
+** This routine sets the progress callback for an Sqlite database to the
+** given callback function with the given argument. The progress callback will
+** be invoked every nOps opcodes.
+*/
+SQLITE_API void sqlite3_progress_handler(
+  sqlite3 *db,
+  int nOps,
+  int (*xProgress)(void*),
+  void *pArg
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( nOps>0 ){
+    db->xProgress = xProgress;
+    db->nProgressOps = (unsigned)nOps;
+    db->pProgressArg = pArg;
+  }else{
+    db->xProgress = 0;
+    db->nProgressOps = 0;
+    db->pProgressArg = 0;
+  }
+  sqlite3_mutex_leave(db->mutex);
+}
+#endif
+
+
+/*
+** This routine installs a default busy handler that waits for the
+** specified number of milliseconds before returning 0.
+*/
+SQLITE_API int sqlite3_busy_timeout(sqlite3 *db, int ms){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  if( ms>0 ){
+    sqlite3_busy_handler(db, (int(*)(void*,int))sqliteDefaultBusyCallback,
+                             (void*)db);
+    db->busyTimeout = ms;
+  }else{
+    sqlite3_busy_handler(db, 0, 0);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Cause any pending operation to stop at its earliest opportunity.
+*/
+SQLITE_API void sqlite3_interrupt(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db)
+   && (db==0 || db->eOpenState!=SQLITE_STATE_ZOMBIE)
+  ){
+    (void)SQLITE_MISUSE_BKPT;
+    return;
+  }
+#endif
+  AtomicStore(&db->u1.isInterrupted, 1);
+}
+
+/*
+** Return true or false depending on whether or not an interrupt is
+** pending on connection db.
+*/
+SQLITE_API int sqlite3_is_interrupted(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db)
+   && (db==0 || db->eOpenState!=SQLITE_STATE_ZOMBIE)
+  ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return AtomicLoad(&db->u1.isInterrupted)!=0;
+}
+
+/*
+** This function is exactly the same as sqlite3_create_function(), except
+** that it is designed to be called by internal code. The difference is
+** that if a malloc() fails in sqlite3_create_function(), an error code
+** is returned and the mallocFailed flag cleared.
+*/
+SQLITE_PRIVATE int sqlite3CreateFunc(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int enc,
+  void *pUserData,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
+  FuncDestructor *pDestructor
+){
+  FuncDef *p;
+  int extraFlags;
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( xValue==0 || xSFunc==0 );
+  if( zFunctionName==0                /* Must have a valid name */
+   || (xSFunc!=0 && xFinal!=0)        /* Not both xSFunc and xFinal */
+   || ((xFinal==0)!=(xStep==0))       /* Both or neither of xFinal and xStep */
+   || ((xValue==0)!=(xInverse==0))    /* Both or neither of xValue, xInverse */
+   || (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG)
+   || (255<sqlite3Strlen30(zFunctionName))
+  ){
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
+  assert( SQLITE_FUNC_DIRECT==SQLITE_DIRECTONLY );
+  extraFlags = enc &  (SQLITE_DETERMINISTIC|SQLITE_DIRECTONLY|
+                       SQLITE_SUBTYPE|SQLITE_INNOCUOUS|
+                       SQLITE_RESULT_SUBTYPE|SQLITE_SELFORDER1);
+  enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
+
+  /* The SQLITE_INNOCUOUS flag is the same bit as SQLITE_FUNC_UNSAFE.  But
+  ** the meaning is inverted.  So flip the bit. */
+  assert( SQLITE_FUNC_UNSAFE==SQLITE_INNOCUOUS );
+  extraFlags ^= SQLITE_FUNC_UNSAFE;  /* tag-20230109-1 */
+
+
+#ifndef SQLITE_OMIT_UTF16
+  /* If SQLITE_UTF16 is specified as the encoding type, transform this
+  ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
+  ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
+  **
+  ** If SQLITE_ANY is specified, add three versions of the function
+  ** to the hash table.
+  */
+  switch( enc ){
+    case SQLITE_UTF16:
+      enc = SQLITE_UTF16NATIVE;
+      break;
+    case SQLITE_ANY: {
+      int rc;
+      rc = sqlite3CreateFunc(db, zFunctionName, nArg,
+           (SQLITE_UTF8|extraFlags)^SQLITE_FUNC_UNSAFE, /* tag-20230109-1 */
+           pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3CreateFunc(db, zFunctionName, nArg,
+             (SQLITE_UTF16LE|extraFlags)^SQLITE_FUNC_UNSAFE, /* tag-20230109-1*/
+             pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
+      }
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      enc = SQLITE_UTF16BE;
+      break;
+    }
+    case SQLITE_UTF8:
+    case SQLITE_UTF16LE:
+    case SQLITE_UTF16BE:
+      break;
+    default:
+      enc = SQLITE_UTF8;
+      break;
+  }
+#else
+  enc = SQLITE_UTF8;
+#endif
+
+  /* Check if an existing function is being overridden or deleted. If so,
+  ** and there are active VMs, then return SQLITE_BUSY. If a function
+  ** is being overridden/deleted but there are no active VMs, allow the
+  ** operation to continue but invalidate all precompiled statements.
+  */
+  p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
+  if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==(u32)enc && p->nArg==nArg ){
+    if( db->nVdbeActive ){
+      sqlite3ErrorWithMsg(db, SQLITE_BUSY,
+        "unable to delete/modify user-function due to active statements");
+      assert( !db->mallocFailed );
+      return SQLITE_BUSY;
+    }else{
+      sqlite3ExpirePreparedStatements(db, 0);
+    }
+  }else if( xSFunc==0 && xFinal==0 ){
+    /* Trying to delete a function that does not exist.  This is a no-op.
+    ** https://sqlite.org/forum/forumpost/726219164b */
+    return SQLITE_OK;
+  }
+
+  p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
+  assert(p || db->mallocFailed);
+  if( !p ){
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  /* If an older version of the function with a configured destructor is
+  ** being replaced invoke the destructor function here. */
+  functionDestroy(db, p);
+
+  if( pDestructor ){
+    pDestructor->nRef++;
+  }
+  p->u.pDestructor = pDestructor;
+  p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
+  testcase( p->funcFlags & SQLITE_DETERMINISTIC );
+  testcase( p->funcFlags & SQLITE_DIRECTONLY );
+  p->xSFunc = xSFunc ? xSFunc : xStep;
+  p->xFinalize = xFinal;
+  p->xValue = xValue;
+  p->xInverse = xInverse;
+  p->pUserData = pUserData;
+  p->nArg = (u16)nArg;
+  return SQLITE_OK;
+}
+
+/*
+** Worker function used by utf-8 APIs that create new functions:
+**
+**    sqlite3_create_function()
+**    sqlite3_create_function_v2()
+**    sqlite3_create_window_function()
+*/
+static int createFunctionApi(
+  sqlite3 *db,
+  const char *zFunc,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
+  void(*xDestroy)(void*)
+){
+  int rc = SQLITE_ERROR;
+  FuncDestructor *pArg = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( xDestroy ){
+    pArg = (FuncDestructor *)sqlite3Malloc(sizeof(FuncDestructor));
+    if( !pArg ){
+      sqlite3OomFault(db);
+      xDestroy(p);
+      goto out;
+    }
+    pArg->nRef = 0;
+    pArg->xDestroy = xDestroy;
+    pArg->pUserData = p;
+  }
+  rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p,
+      xSFunc, xStep, xFinal, xValue, xInverse, pArg
+  );
+  if( pArg && pArg->nRef==0 ){
+    assert( rc!=SQLITE_OK || (xStep==0 && xFinal==0) );
+    xDestroy(p);
+    sqlite3_free(pArg);
+  }
+
+ out:
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Create new user functions.
+*/
+SQLITE_API int sqlite3_create_function(
+  sqlite3 *db,
+  const char *zFunc,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*)
+){
+  return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
+                                    xFinal, 0, 0, 0);
+}
+SQLITE_API int sqlite3_create_function_v2(
+  sqlite3 *db,
+  const char *zFunc,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*),
+  void (*xDestroy)(void *)
+){
+  return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
+                                    xFinal, 0, 0, xDestroy);
+}
+SQLITE_API int sqlite3_create_window_function(
+  sqlite3 *db,
+  const char *zFunc,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
+  void (*xDestroy)(void *)
+){
+  return createFunctionApi(db, zFunc, nArg, enc, p, 0, xStep,
+                                    xFinal, xValue, xInverse, xDestroy);
+}
+
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API int sqlite3_create_function16(
+  sqlite3 *db,
+  const void *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *p,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+){
+  int rc;
+  char *zFunc8;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
+  rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0,0,0);
+  sqlite3DbFree(db, zFunc8);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+#endif
+
+
+/*
+** The following is the implementation of an SQL function that always
+** fails with an error message stating that the function is used in the
+** wrong context.  The sqlite3_overload_function() API might construct
+** SQL function that use this routine so that the functions will exist
+** for name resolution but are actually overloaded by the xFindFunction
+** method of virtual tables.
+*/
+static void sqlite3InvalidFunction(
+  sqlite3_context *context,  /* The function calling context */
+  int NotUsed,               /* Number of arguments to the function */
+  sqlite3_value **NotUsed2   /* Value of each argument */
+){
+  const char *zName = (const char*)sqlite3_user_data(context);
+  char *zErr;
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  zErr = sqlite3_mprintf(
+      "unable to use function %s in the requested context", zName);
+  sqlite3_result_error(context, zErr, -1);
+  sqlite3_free(zErr);
+}
+
+/*
+** Declare that a function has been overloaded by a virtual table.
+**
+** If the function already exists as a regular global function, then
+** this routine is a no-op.  If the function does not exist, then create
+** a new one that always throws a run-time error.
+**
+** When virtual tables intend to provide an overloaded function, they
+** should call this routine to make sure the global function exists.
+** A global function must exist in order for name resolution to work
+** properly.
+*/
+SQLITE_API int sqlite3_overload_function(
+  sqlite3 *db,
+  const char *zName,
+  int nArg
+){
+  int rc;
+  char *zCopy;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  rc = sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)!=0;
+  sqlite3_mutex_leave(db->mutex);
+  if( rc ) return SQLITE_OK;
+  zCopy = sqlite3_mprintf("%s", zName);
+  if( zCopy==0 ) return SQLITE_NOMEM;
+  return sqlite3_create_function_v2(db, zName, nArg, SQLITE_UTF8,
+                           zCopy, sqlite3InvalidFunction, 0, 0, sqlite3_free);
+}
+
+#ifndef SQLITE_OMIT_TRACE
+/*
+** Register a trace function.  The pArg from the previously registered trace
+** is returned.
+**
+** A NULL trace function means that no tracing is executes.  A non-NULL
+** trace is a pointer to a function that is invoked at the start of each
+** SQL statement.
+*/
+#ifndef SQLITE_OMIT_DEPRECATED
+SQLITE_API void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
+  void *pOld;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pOld = db->pTraceArg;
+  db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
+  db->trace.xLegacy = xTrace;
+  db->pTraceArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pOld;
+}
+#endif /* SQLITE_OMIT_DEPRECATED */
+
+/* Register a trace callback using the version-2 interface.
+*/
+SQLITE_API int sqlite3_trace_v2(
+  sqlite3 *db,                               /* Trace this connection */
+  unsigned mTrace,                           /* Mask of events to be traced */
+  int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
+  void *pArg                                 /* Context */
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( mTrace==0 ) xTrace = 0;
+  if( xTrace==0 ) mTrace = 0;
+  db->mTrace = mTrace;
+  db->trace.xV2 = xTrace;
+  db->pTraceArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Register a profile function.  The pArg from the previously registered
+** profile function is returned.
+**
+** A NULL profile function means that no profiling is executes.  A non-NULL
+** profile is a pointer to a function that is invoked at the conclusion of
+** each SQL statement that is run.
+*/
+SQLITE_API void *sqlite3_profile(
+  sqlite3 *db,
+  void (*xProfile)(void*,const char*,sqlite_uint64),
+  void *pArg
+){
+  void *pOld;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pOld = db->pProfileArg;
+  db->xProfile = xProfile;
+  db->pProfileArg = pArg;
+  db->mTrace &= SQLITE_TRACE_NONLEGACY_MASK;
+  if( db->xProfile ) db->mTrace |= SQLITE_TRACE_XPROFILE;
+  sqlite3_mutex_leave(db->mutex);
+  return pOld;
+}
+#endif /* SQLITE_OMIT_DEPRECATED */
+#endif /* SQLITE_OMIT_TRACE */
+
+/*
+** Register a function to be invoked when a transaction commits.
+** If the invoked function returns non-zero, then the commit becomes a
+** rollback.
+*/
+SQLITE_API void *sqlite3_commit_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  int (*xCallback)(void*),  /* Function to invoke on each commit */
+  void *pArg                /* Argument to the function */
+){
+  void *pOld;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pOld = db->pCommitArg;
+  db->xCommitCallback = xCallback;
+  db->pCommitArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pOld;
+}
+
+/*
+** Register a callback to be invoked each time a row is updated,
+** inserted or deleted using this database connection.
+*/
+SQLITE_API void *sqlite3_update_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
+  void *pArg                /* Argument to the function */
+){
+  void *pRet;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pUpdateArg;
+  db->xUpdateCallback = xCallback;
+  db->pUpdateArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+}
+
+/*
+** Register a callback to be invoked each time a transaction is rolled
+** back by this database connection.
+*/
+SQLITE_API void *sqlite3_rollback_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  void (*xCallback)(void*), /* Callback function */
+  void *pArg                /* Argument to the function */
+){
+  void *pRet;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pRollbackArg;
+  db->xRollbackCallback = xCallback;
+  db->pRollbackArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+}
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** Register a callback to be invoked each time a row is updated,
+** inserted or deleted using this database connection.
+*/
+SQLITE_API void *sqlite3_preupdate_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  void(*xCallback)(         /* Callback function */
+    void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
+  void *pArg                /* First callback argument */
+){
+  void *pRet;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( db==0 ){
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pPreUpdateArg;
+  db->xPreUpdateCallback = xCallback;
+  db->pPreUpdateArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+/*
+** Register a function to be invoked prior to each autovacuum that
+** determines the number of pages to vacuum.
+*/
+SQLITE_API int sqlite3_autovacuum_pages(
+  sqlite3 *db,                 /* Attach the hook to this database */
+  unsigned int (*xCallback)(void*,const char*,u32,u32,u32),
+  void *pArg,                  /* Argument to the function */
+  void (*xDestructor)(void*)   /* Destructor for pArg */
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    if( xDestructor ) xDestructor(pArg);
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( db->xAutovacDestr ){
+    db->xAutovacDestr(db->pAutovacPagesArg);
+  }
+  db->xAutovacPages = xCallback;
+  db->pAutovacPagesArg = pArg;
+  db->xAutovacDestr = xDestructor;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
+** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
+** is greater than sqlite3.pWalArg cast to an integer (the value configured by
+** wal_autocheckpoint()).
+*/
+SQLITE_PRIVATE int sqlite3WalDefaultHook(
+  void *pClientData,     /* Argument */
+  sqlite3 *db,           /* Connection */
+  const char *zDb,       /* Database */
+  int nFrame             /* Size of WAL */
+){
+  if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
+    sqlite3BeginBenignMalloc();
+    sqlite3_wal_checkpoint(db, zDb);
+    sqlite3EndBenignMalloc();
+  }
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_WAL */
+
+/*
+** Configure an sqlite3_wal_hook() callback to automatically checkpoint
+** a database after committing a transaction if there are nFrame or
+** more frames in the log file. Passing zero or a negative value as the
+** nFrame parameter disables automatic checkpoints entirely.
+**
+** The callback registered by this function replaces any existing callback
+** registered using sqlite3_wal_hook(). Likewise, registering a callback
+** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
+** configured by this function.
+*/
+SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
+#ifdef SQLITE_OMIT_WAL
+  UNUSED_PARAMETER(db);
+  UNUSED_PARAMETER(nFrame);
+#else
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  if( nFrame>0 ){
+    sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
+  }else{
+    sqlite3_wal_hook(db, 0, 0);
+  }
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Register a callback to be invoked each time a transaction is written
+** into the write-ahead-log by this database connection.
+*/
+SQLITE_API void *sqlite3_wal_hook(
+  sqlite3 *db,                    /* Attach the hook to this db handle */
+  int(*xCallback)(void *, sqlite3*, const char*, int),
+  void *pArg                      /* First argument passed to xCallback() */
+){
+#ifndef SQLITE_OMIT_WAL
+  void *pRet;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pWalArg;
+  db->xWalCallback = xCallback;
+  db->pWalArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+#else
+  return 0;
+#endif
+}
+
+/*
+** Checkpoint database zDb.
+*/
+SQLITE_API int sqlite3_wal_checkpoint_v2(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of attached database (or NULL) */
+  int eMode,                      /* SQLITE_CHECKPOINT_* value */
+  int *pnLog,                     /* OUT: Size of WAL log in frames */
+  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
+){
+#ifdef SQLITE_OMIT_WAL
+  return SQLITE_OK;
+#else
+  int rc;                         /* Return code */
+  int iDb;                        /* Schema to checkpoint */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+
+  /* Initialize the output variables to -1 in case an error occurs. */
+  if( pnLog ) *pnLog = -1;
+  if( pnCkpt ) *pnCkpt = -1;
+
+  assert( SQLITE_CHECKPOINT_PASSIVE==0 );
+  assert( SQLITE_CHECKPOINT_FULL==1 );
+  assert( SQLITE_CHECKPOINT_RESTART==2 );
+  assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
+  if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
+    /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
+    ** mode: */
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  sqlite3_mutex_enter(db->mutex);
+  if( zDb && zDb[0] ){
+    iDb = sqlite3FindDbName(db, zDb);
+  }else{
+    iDb = SQLITE_MAX_DB;   /* This means process all schemas */
+  }
+  if( iDb<0 ){
+    rc = SQLITE_ERROR;
+    sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
+  }else{
+    db->busyHandler.nBusy = 0;
+    rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
+    sqlite3Error(db, rc);
+  }
+  rc = sqlite3ApiExit(db, rc);
+
+  /* If there are no active statements, clear the interrupt flag at this
+  ** point.  */
+  if( db->nVdbeActive==0 ){
+    AtomicStore(&db->u1.isInterrupted, 0);
+  }
+
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+#endif
+}
+
+
+/*
+** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
+** to contains a zero-length string, all attached databases are
+** checkpointed.
+*/
+SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
+  /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
+  ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
+  return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** Run a checkpoint on database iDb. This is a no-op if database iDb is
+** not currently open in WAL mode.
+**
+** If a transaction is open on the database being checkpointed, this
+** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
+** an error occurs while running the checkpoint, an SQLite error code is
+** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
+**
+** The mutex on database handle db should be held by the caller. The mutex
+** associated with the specific b-tree being checkpointed is taken by
+** this function while the checkpoint is running.
+**
+** If iDb is passed SQLITE_MAX_DB then all attached databases are
+** checkpointed. If an error is encountered it is returned immediately -
+** no attempt is made to checkpoint any remaining databases.
+**
+** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL, RESTART
+** or TRUNCATE.
+*/
+SQLITE_PRIVATE int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Used to iterate through attached dbs */
+  int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( !pnLog || *pnLog==-1 );
+  assert( !pnCkpt || *pnCkpt==-1 );
+  testcase( iDb==SQLITE_MAX_ATTACHED ); /* See forum post a006d86f72 */
+  testcase( iDb==SQLITE_MAX_DB );
+
+  for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
+    if( i==iDb || iDb==SQLITE_MAX_DB ){
+      rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
+      pnLog = 0;
+      pnCkpt = 0;
+      if( rc==SQLITE_BUSY ){
+        bBusy = 1;
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+  return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
+}
+#endif /* SQLITE_OMIT_WAL */
+
+/*
+** This function returns true if main-memory should be used instead of
+** a temporary file for transient pager files and statement journals.
+** The value returned depends on the value of db->temp_store (runtime
+** parameter) and the compile time value of SQLITE_TEMP_STORE. The
+** following table describes the relationship between these two values
+** and this functions return value.
+**
+**   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
+**   -----------------     --------------     ------------------------------
+**   0                     any                file      (return 0)
+**   1                     1                  file      (return 0)
+**   1                     2                  memory    (return 1)
+**   1                     0                  file      (return 0)
+**   2                     1                  file      (return 0)
+**   2                     2                  memory    (return 1)
+**   2                     0                  memory    (return 1)
+**   3                     any                memory    (return 1)
+*/
+SQLITE_PRIVATE int sqlite3TempInMemory(const sqlite3 *db){
+#if SQLITE_TEMP_STORE==1
+  return ( db->temp_store==2 );
+#endif
+#if SQLITE_TEMP_STORE==2
+  return ( db->temp_store!=1 );
+#endif
+#if SQLITE_TEMP_STORE==3
+  UNUSED_PARAMETER(db);
+  return 1;
+#endif
+#if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
+  UNUSED_PARAMETER(db);
+  return 0;
+#endif
+}
+
+/*
+** Return UTF-8 encoded English language explanation of the most recent
+** error.
+*/
+SQLITE_API const char *sqlite3_errmsg(sqlite3 *db){
+  const char *z;
+  if( !db ){
+    return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
+  }
+  if( !sqlite3SafetyCheckSickOrOk(db) ){
+    return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
+  }
+  sqlite3_mutex_enter(db->mutex);
+  if( db->mallocFailed ){
+    z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
+  }else{
+    testcase( db->pErr==0 );
+    z = db->errCode ? (char*)sqlite3_value_text(db->pErr) : 0;
+    assert( !db->mallocFailed );
+    if( z==0 ){
+      z = sqlite3ErrStr(db->errCode);
+    }
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return z;
+}
+
+/*
+** Return the byte offset of the most recent error
+*/
+SQLITE_API int sqlite3_error_offset(sqlite3 *db){
+  int iOffset = -1;
+  if( db && sqlite3SafetyCheckSickOrOk(db) && db->errCode ){
+    sqlite3_mutex_enter(db->mutex);
+    iOffset = db->errByteOffset;
+    sqlite3_mutex_leave(db->mutex);
+  }
+  return iOffset;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Return UTF-16 encoded English language explanation of the most recent
+** error.
+*/
+SQLITE_API const void *sqlite3_errmsg16(sqlite3 *db){
+  static const u16 outOfMem[] = {
+    'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
+  };
+  static const u16 misuse[] = {
+    'b', 'a', 'd', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'e', 'r', ' ',
+    'o', 'r', ' ', 'o', 't', 'h', 'e', 'r', ' ', 'A', 'P', 'I', ' ',
+    'm', 'i', 's', 'u', 's', 'e', 0
+  };
+
+  const void *z;
+  if( !db ){
+    return (void *)outOfMem;
+  }
+  if( !sqlite3SafetyCheckSickOrOk(db) ){
+    return (void *)misuse;
+  }
+  sqlite3_mutex_enter(db->mutex);
+  if( db->mallocFailed ){
+    z = (void *)outOfMem;
+  }else{
+    z = sqlite3_value_text16(db->pErr);
+    if( z==0 ){
+      sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
+      z = sqlite3_value_text16(db->pErr);
+    }
+    /* A malloc() may have failed within the call to sqlite3_value_text16()
+    ** above. If this is the case, then the db->mallocFailed flag needs to
+    ** be cleared before returning. Do this directly, instead of via
+    ** sqlite3ApiExit(), to avoid setting the database handle error message.
+    */
+    sqlite3OomClear(db);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return z;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Return the most recent error code generated by an SQLite routine. If NULL is
+** passed to this function, we assume a malloc() failed during sqlite3_open().
+*/
+SQLITE_API int sqlite3_errcode(sqlite3 *db){
+  if( db && !sqlite3SafetyCheckSickOrOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  if( !db || db->mallocFailed ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  return db->errCode & db->errMask;
+}
+SQLITE_API int sqlite3_extended_errcode(sqlite3 *db){
+  if( db && !sqlite3SafetyCheckSickOrOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  if( !db || db->mallocFailed ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  return db->errCode;
+}
+SQLITE_API int sqlite3_system_errno(sqlite3 *db){
+  return db ? db->iSysErrno : 0;
+}
+
+/*
+** Return a string that describes the kind of error specified in the
+** argument.  For now, this simply calls the internal sqlite3ErrStr()
+** function.
+*/
+SQLITE_API const char *sqlite3_errstr(int rc){
+  return sqlite3ErrStr(rc);
+}
+
+/*
+** Create a new collating function for database "db".  The name is zName
+** and the encoding is enc.
+*/
+static int createCollation(
+  sqlite3* db,
+  const char *zName,
+  u8 enc,
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDel)(void*)
+){
+  CollSeq *pColl;
+  int enc2;
+
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  /* If SQLITE_UTF16 is specified as the encoding type, transform this
+  ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
+  ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
+  */
+  enc2 = enc;
+  testcase( enc2==SQLITE_UTF16 );
+  testcase( enc2==SQLITE_UTF16_ALIGNED );
+  if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
+    enc2 = SQLITE_UTF16NATIVE;
+  }
+  if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  /* Check if this call is removing or replacing an existing collation
+  ** sequence. If so, and there are active VMs, return busy. If there
+  ** are no active VMs, invalidate any pre-compiled statements.
+  */
+  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
+  if( pColl && pColl->xCmp ){
+    if( db->nVdbeActive ){
+      sqlite3ErrorWithMsg(db, SQLITE_BUSY,
+        "unable to delete/modify collation sequence due to active statements");
+      return SQLITE_BUSY;
+    }
+    sqlite3ExpirePreparedStatements(db, 0);
+
+    /* If collation sequence pColl was created directly by a call to
+    ** sqlite3_create_collation, and not generated by synthCollSeq(),
+    ** then any copies made by synthCollSeq() need to be invalidated.
+    ** Also, collation destructor - CollSeq.xDel() - function may need
+    ** to be called.
+    */
+    if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
+      CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
+      int j;
+      for(j=0; j<3; j++){
+        CollSeq *p = &aColl[j];
+        if( p->enc==pColl->enc ){
+          if( p->xDel ){
+            p->xDel(p->pUser);
+          }
+          p->xCmp = 0;
+        }
+      }
+    }
+  }
+
+  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
+  if( pColl==0 ) return SQLITE_NOMEM_BKPT;
+  pColl->xCmp = xCompare;
+  pColl->pUser = pCtx;
+  pColl->xDel = xDel;
+  pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
+  sqlite3Error(db, SQLITE_OK);
+  return SQLITE_OK;
+}
+
+
+/*
+** This array defines hard upper bounds on limit values.  The
+** initializer must be kept in sync with the SQLITE_LIMIT_*
+** #defines in sqlite3.h.
+*/
+static const int aHardLimit[] = {
+  SQLITE_MAX_LENGTH,
+  SQLITE_MAX_SQL_LENGTH,
+  SQLITE_MAX_COLUMN,
+  SQLITE_MAX_EXPR_DEPTH,
+  SQLITE_MAX_COMPOUND_SELECT,
+  SQLITE_MAX_VDBE_OP,
+  SQLITE_MAX_FUNCTION_ARG,
+  SQLITE_MAX_ATTACHED,
+  SQLITE_MAX_LIKE_PATTERN_LENGTH,
+  SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
+  SQLITE_MAX_TRIGGER_DEPTH,
+  SQLITE_MAX_WORKER_THREADS,
+};
+
+/*
+** Make sure the hard limits are set to reasonable values
+*/
+#if SQLITE_MAX_LENGTH<100
+# error SQLITE_MAX_LENGTH must be at least 100
+#endif
+#if SQLITE_MAX_SQL_LENGTH<100
+# error SQLITE_MAX_SQL_LENGTH must be at least 100
+#endif
+#if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
+# error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
+#endif
+#if SQLITE_MAX_COMPOUND_SELECT<2
+# error SQLITE_MAX_COMPOUND_SELECT must be at least 2
+#endif
+#if SQLITE_MAX_VDBE_OP<40
+# error SQLITE_MAX_VDBE_OP must be at least 40
+#endif
+#if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>32767
+# error SQLITE_MAX_FUNCTION_ARG must be between 0 and 32767
+#endif
+#if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
+# error SQLITE_MAX_ATTACHED must be between 0 and 125
+#endif
+#if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
+# error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
+#endif
+#if SQLITE_MAX_COLUMN>32767
+# error SQLITE_MAX_COLUMN must not exceed 32767
+#endif
+#if SQLITE_MAX_TRIGGER_DEPTH<1
+# error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
+#endif
+#if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
+# error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
+#endif
+
+
+/*
+** Change the value of a limit.  Report the old value.
+** If an invalid limit index is supplied, report -1.
+** Make no changes but still report the old value if the
+** new limit is negative.
+**
+** A new lower limit does not shrink existing constructs.
+** It merely prevents new constructs that exceed the limit
+** from forming.
+*/
+SQLITE_API int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
+  int oldLimit;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return -1;
+  }
+#endif
+
+  /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
+  ** there is a hard upper bound set at compile-time by a C preprocessor
+  ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
+  ** "_MAX_".)
+  */
+  assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
+  assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
+  assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
+  assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
+  assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
+  assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
+  assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
+  assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
+  assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
+                                               SQLITE_MAX_LIKE_PATTERN_LENGTH );
+  assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
+  assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
+  assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
+  assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
+
+
+  if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
+    return -1;
+  }
+  oldLimit = db->aLimit[limitId];
+  if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
+    if( newLimit>aHardLimit[limitId] ){
+      newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
+    }else if( newLimit<SQLITE_MIN_LENGTH && limitId==SQLITE_LIMIT_LENGTH ){
+      newLimit = SQLITE_MIN_LENGTH;
+    }
+    db->aLimit[limitId] = newLimit;
+  }
+  return oldLimit;                     /* IMP: R-53341-35419 */
+}
+
+/*
+** This function is used to parse both URIs and non-URI filenames passed by the
+** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
+** URIs specified as part of ATTACH statements.
+**
+** The first argument to this function is the name of the VFS to use (or
+** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
+** query parameter. The second argument contains the URI (or non-URI filename)
+** itself. When this function is called the *pFlags variable should contain
+** the default flags to open the database handle with. The value stored in
+** *pFlags may be updated before returning if the URI filename contains
+** "cache=xxx" or "mode=xxx" query parameters.
+**
+** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
+** the VFS that should be used to open the database file. *pzFile is set to
+** point to a buffer containing the name of the file to open.  The value
+** stored in *pzFile is a database name acceptable to sqlite3_uri_parameter()
+** and is in the same format as names created using sqlite3_create_filename().
+** The caller must invoke sqlite3_free_filename() (not sqlite3_free()!) on
+** the value returned in *pzFile to avoid a memory leak.
+**
+** If an error occurs, then an SQLite error code is returned and *pzErrMsg
+** may be set to point to a buffer containing an English language error
+** message. It is the responsibility of the caller to eventually release
+** this buffer by calling sqlite3_free().
+*/
+SQLITE_PRIVATE int sqlite3ParseUri(
+  const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
+  const char *zUri,               /* Nul-terminated URI to parse */
+  unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
+  sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
+  char **pzFile,                  /* OUT: Filename component of URI */
+  char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
+){
+  int rc = SQLITE_OK;
+  unsigned int flags = *pFlags;
+  const char *zVfs = zDefaultVfs;
+  char *zFile;
+  char c;
+  int nUri = sqlite3Strlen30(zUri);
+
+  assert( *pzErrMsg==0 );
+
+  if( ((flags & SQLITE_OPEN_URI)                     /* IMP: R-48725-32206 */
+       || AtomicLoad(&sqlite3GlobalConfig.bOpenUri)) /* IMP: R-51689-46548 */
+   && nUri>=5 && memcmp(zUri, "file:", 5)==0         /* IMP: R-57884-37496 */
+  ){
+    char *zOpt;
+    int eState;                   /* Parser state when parsing URI */
+    int iIn;                      /* Input character index */
+    int iOut = 0;                 /* Output character index */
+    u64 nByte = nUri+8;           /* Bytes of space to allocate */
+
+    /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
+    ** method that there may be extra parameters following the file-name.  */
+    flags |= SQLITE_OPEN_URI;
+
+    for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
+    zFile = sqlite3_malloc64(nByte);
+    if( !zFile ) return SQLITE_NOMEM_BKPT;
+
+    memset(zFile, 0, 4);  /* 4-byte of 0x00 is the start of DB name marker */
+    zFile += 4;
+
+    iIn = 5;
+#ifdef SQLITE_ALLOW_URI_AUTHORITY
+    if( strncmp(zUri+5, "///", 3)==0 ){
+      iIn = 7;
+      /* The following condition causes URIs with five leading / characters
+      ** like file://///host/path to be converted into UNCs like //host/path.
+      ** The correct URI for that UNC has only two or four leading / characters
+      ** file://host/path or file:////host/path.  But 5 leading slashes is a
+      ** common error, we are told, so we handle it as a special case. */
+      if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
+    }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
+      iIn = 16;
+    }
+#else
+    /* Discard the scheme and authority segments of the URI. */
+    if( zUri[5]=='/' && zUri[6]=='/' ){
+      iIn = 7;
+      while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
+      if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
+        *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
+            iIn-7, &zUri[7]);
+        rc = SQLITE_ERROR;
+        goto parse_uri_out;
+      }
+    }
+#endif
+
+    /* Copy the filename and any query parameters into the zFile buffer.
+    ** Decode %HH escape codes along the way.
+    **
+    ** Within this loop, variable eState may be set to 0, 1 or 2, depending
+    ** on the parsing context. As follows:
+    **
+    **   0: Parsing file-name.
+    **   1: Parsing name section of a name=value query parameter.
+    **   2: Parsing value section of a name=value query parameter.
+    */
+    eState = 0;
+    while( (c = zUri[iIn])!=0 && c!='#' ){
+      iIn++;
+      if( c=='%'
+       && sqlite3Isxdigit(zUri[iIn])
+       && sqlite3Isxdigit(zUri[iIn+1])
+      ){
+        int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
+        octet += sqlite3HexToInt(zUri[iIn++]);
+
+        assert( octet>=0 && octet<256 );
+        if( octet==0 ){
+#ifndef SQLITE_ENABLE_URI_00_ERROR
+          /* This branch is taken when "%00" appears within the URI. In this
+          ** case we ignore all text in the remainder of the path, name or
+          ** value currently being parsed. So ignore the current character
+          ** and skip to the next "?", "=" or "&", as appropriate. */
+          while( (c = zUri[iIn])!=0 && c!='#'
+              && (eState!=0 || c!='?')
+              && (eState!=1 || (c!='=' && c!='&'))
+              && (eState!=2 || c!='&')
+          ){
+            iIn++;
+          }
+          continue;
+#else
+          /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
+          *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
+          rc = SQLITE_ERROR;
+          goto parse_uri_out;
+#endif
+        }
+        c = octet;
+      }else if( eState==1 && (c=='&' || c=='=') ){
+        if( zFile[iOut-1]==0 ){
+          /* An empty option name. Ignore this option altogether. */
+          while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
+          continue;
+        }
+        if( c=='&' ){
+          zFile[iOut++] = '\0';
+        }else{
+          eState = 2;
+        }
+        c = 0;
+      }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
+        c = 0;
+        eState = 1;
+      }
+      zFile[iOut++] = c;
+    }
+    if( eState==1 ) zFile[iOut++] = '\0';
+    memset(zFile+iOut, 0, 4); /* end-of-options + empty journal filenames */
+
+    /* Check if there were any options specified that should be interpreted
+    ** here. Options that are interpreted here include "vfs" and those that
+    ** correspond to flags that may be passed to the sqlite3_open_v2()
+    ** method. */
+    zOpt = &zFile[sqlite3Strlen30(zFile)+1];
+    while( zOpt[0] ){
+      int nOpt = sqlite3Strlen30(zOpt);
+      char *zVal = &zOpt[nOpt+1];
+      int nVal = sqlite3Strlen30(zVal);
+
+      if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
+        zVfs = zVal;
+      }else{
+        struct OpenMode {
+          const char *z;
+          int mode;
+        } *aMode = 0;
+        char *zModeType = 0;
+        int mask = 0;
+        int limit = 0;
+
+        if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
+          static struct OpenMode aCacheMode[] = {
+            { "shared",  SQLITE_OPEN_SHAREDCACHE },
+            { "private", SQLITE_OPEN_PRIVATECACHE },
+            { 0, 0 }
+          };
+
+          mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
+          aMode = aCacheMode;
+          limit = mask;
+          zModeType = "cache";
+        }
+        if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
+          static struct OpenMode aOpenMode[] = {
+            { "ro",  SQLITE_OPEN_READONLY },
+            { "rw",  SQLITE_OPEN_READWRITE },
+            { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
+            { "memory", SQLITE_OPEN_MEMORY },
+            { 0, 0 }
+          };
+
+          mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
+                   | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
+          aMode = aOpenMode;
+          limit = mask & flags;
+          zModeType = "access";
+        }
+
+        if( aMode ){
+          int i;
+          int mode = 0;
+          for(i=0; aMode[i].z; i++){
+            const char *z = aMode[i].z;
+            if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
+              mode = aMode[i].mode;
+              break;
+            }
+          }
+          if( mode==0 ){
+            *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
+            rc = SQLITE_ERROR;
+            goto parse_uri_out;
+          }
+          if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
+            *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
+                                        zModeType, zVal);
+            rc = SQLITE_PERM;
+            goto parse_uri_out;
+          }
+          flags = (flags & ~mask) | mode;
+        }
+      }
+
+      zOpt = &zVal[nVal+1];
+    }
+
+  }else{
+    zFile = sqlite3_malloc64(nUri+8);
+    if( !zFile ) return SQLITE_NOMEM_BKPT;
+    memset(zFile, 0, 4);
+    zFile += 4;
+    if( nUri ){
+      memcpy(zFile, zUri, nUri);
+    }
+    memset(zFile+nUri, 0, 4);
+    flags &= ~SQLITE_OPEN_URI;
+  }
+
+  *ppVfs = sqlite3_vfs_find(zVfs);
+  if( *ppVfs==0 ){
+    *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
+    rc = SQLITE_ERROR;
+  }
+ parse_uri_out:
+  if( rc!=SQLITE_OK ){
+    sqlite3_free_filename(zFile);
+    zFile = 0;
+  }
+  *pFlags = flags;
+  *pzFile = zFile;
+  return rc;
+}
+
+/*
+** This routine does the core work of extracting URI parameters from a
+** database filename for the sqlite3_uri_parameter() interface.
+*/
+static const char *uriParameter(const char *zFilename, const char *zParam){
+  zFilename += sqlite3Strlen30(zFilename) + 1;
+  while( ALWAYS(zFilename!=0) && zFilename[0] ){
+    int x = strcmp(zFilename, zParam);
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+    if( x==0 ) return zFilename;
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+  }
+  return 0;
+}
+
+
+
+/*
+** This routine does the work of opening a database on behalf of
+** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
+** is UTF-8 encoded.
+*/
+static int openDatabase(
+  const char *zFilename, /* Database filename UTF-8 encoded */
+  sqlite3 **ppDb,        /* OUT: Returned database handle */
+  unsigned int flags,    /* Operational flags */
+  const char *zVfs       /* Name of the VFS to use */
+){
+  sqlite3 *db;                    /* Store allocated handle here */
+  int rc;                         /* Return code */
+  int isThreadsafe;               /* True for threadsafe connections */
+  char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
+  char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
+  int i;                          /* Loop counter */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *ppDb = 0;
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+
+  if( sqlite3GlobalConfig.bCoreMutex==0 ){
+    isThreadsafe = 0;
+  }else if( flags & SQLITE_OPEN_NOMUTEX ){
+    isThreadsafe = 0;
+  }else if( flags & SQLITE_OPEN_FULLMUTEX ){
+    isThreadsafe = 1;
+  }else{
+    isThreadsafe = sqlite3GlobalConfig.bFullMutex;
+  }
+
+  if( flags & SQLITE_OPEN_PRIVATECACHE ){
+    flags &= ~SQLITE_OPEN_SHAREDCACHE;
+  }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
+    flags |= SQLITE_OPEN_SHAREDCACHE;
+  }
+
+  /* Remove harmful bits from the flags parameter
+  **
+  ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
+  ** dealt with in the previous code block.  Besides these, the only
+  ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
+  ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
+  ** SQLITE_OPEN_PRIVATECACHE, SQLITE_OPEN_EXRESCODE, and some reserved
+  ** bits.  Silently mask off all other flags.
+  */
+  flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
+               SQLITE_OPEN_EXCLUSIVE |
+               SQLITE_OPEN_MAIN_DB |
+               SQLITE_OPEN_TEMP_DB |
+               SQLITE_OPEN_TRANSIENT_DB |
+               SQLITE_OPEN_MAIN_JOURNAL |
+               SQLITE_OPEN_TEMP_JOURNAL |
+               SQLITE_OPEN_SUBJOURNAL |
+               SQLITE_OPEN_SUPER_JOURNAL |
+               SQLITE_OPEN_NOMUTEX |
+               SQLITE_OPEN_FULLMUTEX |
+               SQLITE_OPEN_WAL
+             );
+
+  /* Allocate the sqlite data structure */
+  db = sqlite3MallocZero( sizeof(sqlite3) );
+  if( db==0 ) goto opendb_out;
+  if( isThreadsafe
+#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
+   || sqlite3GlobalConfig.bCoreMutex
+#endif
+  ){
+    db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
+    if( db->mutex==0 ){
+      sqlite3_free(db);
+      db = 0;
+      goto opendb_out;
+    }
+    if( isThreadsafe==0 ){
+      sqlite3MutexWarnOnContention(db->mutex);
+    }
+  }
+  sqlite3_mutex_enter(db->mutex);
+  db->errMask = (flags & SQLITE_OPEN_EXRESCODE)!=0 ? 0xffffffff : 0xff;
+  db->nDb = 2;
+  db->eOpenState = SQLITE_STATE_BUSY;
+  db->aDb = db->aDbStatic;
+  db->lookaside.bDisable = 1;
+  db->lookaside.sz = 0;
+
+  assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
+  memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
+  db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
+  db->autoCommit = 1;
+  db->nextAutovac = -1;
+  db->szMmap = sqlite3GlobalConfig.szMmap;
+  db->nextPagesize = 0;
+  db->init.azInit = sqlite3StdType; /* Any array of string ptrs will do */
+#ifdef SQLITE_ENABLE_SORTER_MMAP
+  /* Beginning with version 3.37.0, using the VFS xFetch() API to memory-map
+  ** the temporary files used to do external sorts (see code in vdbesort.c)
+  ** is disabled. It can still be used either by defining
+  ** SQLITE_ENABLE_SORTER_MMAP at compile time or by using the
+  ** SQLITE_TESTCTRL_SORTER_MMAP test-control at runtime. */
+  db->nMaxSorterMmap = 0x7FFFFFFF;
+#endif
+  db->flags |= SQLITE_ShortColNames
+                 | SQLITE_EnableTrigger
+                 | SQLITE_EnableView
+                 | SQLITE_CacheSpill
+                 | SQLITE_AttachCreate
+                 | SQLITE_AttachWrite
+                 | SQLITE_Comments
+#if !defined(SQLITE_TRUSTED_SCHEMA) || SQLITE_TRUSTED_SCHEMA+0!=0
+                 | SQLITE_TrustedSchema
+#endif
+/* The SQLITE_DQS compile-time option determines the default settings
+** for SQLITE_DBCONFIG_DQS_DDL and SQLITE_DBCONFIG_DQS_DML.
+**
+**    SQLITE_DQS     SQLITE_DBCONFIG_DQS_DDL    SQLITE_DBCONFIG_DQS_DML
+**    ----------     -----------------------    -----------------------
+**     undefined               on                          on
+**         3                   on                          on
+**         2                   on                         off
+**         1                  off                          on
+**         0                  off                         off
+**
+** Legacy behavior is 3 (double-quoted string literals are allowed anywhere)
+** and so that is the default.  But developers are encouraged to use
+** -DSQLITE_DQS=0 (best) or -DSQLITE_DQS=1 (second choice) if possible.
+*/
+#if !defined(SQLITE_DQS)
+# define SQLITE_DQS 3
+#endif
+#if (SQLITE_DQS&1)==1
+                 | SQLITE_DqsDML
+#endif
+#if (SQLITE_DQS&2)==2
+                 | SQLITE_DqsDDL
+#endif
+
+#if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
+                 | SQLITE_AutoIndex
+#endif
+#if SQLITE_DEFAULT_CKPTFULLFSYNC
+                 | SQLITE_CkptFullFSync
+#endif
+#if SQLITE_DEFAULT_FILE_FORMAT<4
+                 | SQLITE_LegacyFileFmt
+#endif
+#ifdef SQLITE_ENABLE_LOAD_EXTENSION
+                 | SQLITE_LoadExtension
+#endif
+#if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
+                 | SQLITE_RecTriggers
+#endif
+#if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
+                 | SQLITE_ForeignKeys
+#endif
+#if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
+                 | SQLITE_ReverseOrder
+#endif
+#if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
+                 | SQLITE_CellSizeCk
+#endif
+#if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
+                 | SQLITE_Fts3Tokenizer
+#endif
+#if defined(SQLITE_ENABLE_QPSG)
+                 | SQLITE_EnableQPSG
+#endif
+#if defined(SQLITE_DEFAULT_DEFENSIVE)
+                 | SQLITE_Defensive
+#endif
+#if defined(SQLITE_DEFAULT_LEGACY_ALTER_TABLE)
+                 | SQLITE_LegacyAlter
+#endif
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+                 | SQLITE_StmtScanStatus
+#endif
+      ;
+  sqlite3HashInit(&db->aCollSeq);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3HashInit(&db->aModule);
+#endif
+
+  /* Add the default collation sequence BINARY. BINARY works for both UTF-8
+  ** and UTF-16, so add a version for each to avoid any unnecessary
+  ** conversions. The only error that can occur here is a malloc() failure.
+  **
+  ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
+  ** functions:
+  */
+  createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
+  createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
+  createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
+  createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
+  createCollation(db, "RTRIM", SQLITE_UTF8, 0, rtrimCollFunc, 0);
+  if( db->mallocFailed ){
+    goto opendb_out;
+  }
+
+#if SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL)
+  /* Process magic filenames ":localStorage:" and ":sessionStorage:" */
+  if( zFilename && zFilename[0]==':' ){
+    if( strcmp(zFilename, ":localStorage:")==0 ){
+      zFilename = "file:local?vfs=kvvfs";
+      flags |= SQLITE_OPEN_URI;
+    }else if( strcmp(zFilename, ":sessionStorage:")==0 ){
+      zFilename = "file:session?vfs=kvvfs";
+      flags |= SQLITE_OPEN_URI;
+    }
+  }
+#endif /* SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL) */
+
+  /* Parse the filename/URI argument
+  **
+  ** Only allow sensible combinations of bits in the flags argument.
+  ** Throw an error if any non-sense combination is used.  If we
+  ** do not block illegal combinations here, it could trigger
+  ** assert() statements in deeper layers.  Sensible combinations
+  ** are:
+  **
+  **  1:  SQLITE_OPEN_READONLY
+  **  2:  SQLITE_OPEN_READWRITE
+  **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
+  */
+  db->openFlags = flags;
+  assert( SQLITE_OPEN_READONLY  == 0x01 );
+  assert( SQLITE_OPEN_READWRITE == 0x02 );
+  assert( SQLITE_OPEN_CREATE    == 0x04 );
+  testcase( (1<<(flags&7))==0x02 ); /* READONLY */
+  testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
+  testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
+  if( ((1<<(flags&7)) & 0x46)==0 ){
+    rc = SQLITE_MISUSE_BKPT;  /* IMP: R-18321-05872 */
+  }else{
+    if( zFilename==0 ) zFilename = ":memory:";
+    rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
+  }
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
+    sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
+    sqlite3_free(zErrMsg);
+    goto opendb_out;
+  }
+  assert( db->pVfs!=0 );
+#if SQLITE_OS_KV || defined(SQLITE_OS_KV_OPTIONAL)
+  if( sqlite3_stricmp(db->pVfs->zName, "kvvfs")==0 ){
+    db->temp_store = 2;
+  }
+#endif
+
+  /* Open the backend database driver */
+  rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
+                        flags | SQLITE_OPEN_MAIN_DB);
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_IOERR_NOMEM ){
+      rc = SQLITE_NOMEM_BKPT;
+    }
+    sqlite3Error(db, rc);
+    goto opendb_out;
+  }
+  sqlite3BtreeEnter(db->aDb[0].pBt);
+  db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
+  if( !db->mallocFailed ){
+    sqlite3SetTextEncoding(db, SCHEMA_ENC(db));
+  }
+  sqlite3BtreeLeave(db->aDb[0].pBt);
+  db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
+
+  /* The default safety_level for the main database is FULL; for the temp
+  ** database it is OFF. This matches the pager layer defaults.
+  */
+  db->aDb[0].zDbSName = "main";
+  db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
+  db->aDb[1].zDbSName = "temp";
+  db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
+
+  db->eOpenState = SQLITE_STATE_OPEN;
+  if( db->mallocFailed ){
+    goto opendb_out;
+  }
+
+  /* Register all built-in functions, but do not attempt to read the
+  ** database schema yet. This is delayed until the first time the database
+  ** is accessed.
+  */
+  sqlite3Error(db, SQLITE_OK);
+  sqlite3RegisterPerConnectionBuiltinFunctions(db);
+  rc = sqlite3_errcode(db);
+
+
+  /* Load compiled-in extensions */
+  for(i=0; rc==SQLITE_OK && i<ArraySize(sqlite3BuiltinExtensions); i++){
+    rc = sqlite3BuiltinExtensions[i](db);
+  }
+
+  /* Load automatic extensions - extensions that have been registered
+  ** using the sqlite3_automatic_extension() API.
+  */
+  if( rc==SQLITE_OK ){
+    sqlite3AutoLoadExtensions(db);
+    rc = sqlite3_errcode(db);
+    if( rc!=SQLITE_OK ){
+      goto opendb_out;
+    }
+  }
+
+#ifdef SQLITE_ENABLE_INTERNAL_FUNCTIONS
+  /* Testing use only!!! The -DSQLITE_ENABLE_INTERNAL_FUNCTIONS=1 compile-time
+  ** option gives access to internal functions by default.
+  ** Testing use only!!! */
+  db->mDbFlags |= DBFLAG_InternalFunc;
+#endif
+
+  /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
+  ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
+  ** mode.  Doing nothing at all also makes NORMAL the default.
+  */
+#ifdef SQLITE_DEFAULT_LOCKING_MODE
+  db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
+  sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
+                          SQLITE_DEFAULT_LOCKING_MODE);
+#endif
+
+  if( rc ) sqlite3Error(db, rc);
+
+  /* Enable the lookaside-malloc subsystem */
+  setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
+                        sqlite3GlobalConfig.nLookaside);
+
+  sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
+
+opendb_out:
+  if( db ){
+    assert( db->mutex!=0 || isThreadsafe==0
+           || sqlite3GlobalConfig.bFullMutex==0 );
+    sqlite3_mutex_leave(db->mutex);
+  }
+  rc = sqlite3_errcode(db);
+  assert( db!=0 || (rc&0xff)==SQLITE_NOMEM );
+  if( (rc&0xff)==SQLITE_NOMEM ){
+    sqlite3_close(db);
+    db = 0;
+  }else if( rc!=SQLITE_OK ){
+    db->eOpenState = SQLITE_STATE_SICK;
+  }
+  *ppDb = db;
+#ifdef SQLITE_ENABLE_SQLLOG
+  if( sqlite3GlobalConfig.xSqllog ){
+    /* Opening a db handle. Fourth parameter is passed 0. */
+    void *pArg = sqlite3GlobalConfig.pSqllogArg;
+    sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
+  }
+#endif
+  sqlite3_free_filename(zOpen);
+  return rc;
+}
+
+
+/*
+** Open a new database handle.
+*/
+SQLITE_API int sqlite3_open(
+  const char *zFilename,
+  sqlite3 **ppDb
+){
+  return openDatabase(zFilename, ppDb,
+                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
+}
+SQLITE_API int sqlite3_open_v2(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb,         /* OUT: SQLite db handle */
+  int flags,              /* Flags */
+  const char *zVfs        /* Name of VFS module to use */
+){
+  return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Open a new database handle.
+*/
+SQLITE_API int sqlite3_open16(
+  const void *zFilename,
+  sqlite3 **ppDb
+){
+  char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
+  sqlite3_value *pVal;
+  int rc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *ppDb = 0;
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+  if( zFilename==0 ) zFilename = "\000\000";
+  pVal = sqlite3ValueNew(0);
+  sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
+  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
+  if( zFilename8 ){
+    rc = openDatabase(zFilename8, ppDb,
+                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
+    assert( *ppDb || rc==SQLITE_NOMEM );
+    if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
+      SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
+    }
+  }else{
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  sqlite3ValueFree(pVal);
+
+  return rc & 0xff;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Register a new collation sequence with the database handle db.
+*/
+SQLITE_API int sqlite3_create_collation(
+  sqlite3* db,
+  const char *zName,
+  int enc,
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+){
+  return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
+}
+
+/*
+** Register a new collation sequence with the database handle db.
+*/
+SQLITE_API int sqlite3_create_collation_v2(
+  sqlite3* db,
+  const char *zName,
+  int enc,
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDel)(void*)
+){
+  int rc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Register a new collation sequence with the database handle db.
+*/
+SQLITE_API int sqlite3_create_collation16(
+  sqlite3* db,
+  const void *zName,
+  int enc,
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+){
+  int rc = SQLITE_OK;
+  char *zName8;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
+  if( zName8 ){
+    rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
+    sqlite3DbFree(db, zName8);
+  }
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Register a collation sequence factory callback with the database handle
+** db. Replace any previously installed collation sequence factory.
+*/
+SQLITE_API int sqlite3_collation_needed(
+  sqlite3 *db,
+  void *pCollNeededArg,
+  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->xCollNeeded = xCollNeeded;
+  db->xCollNeeded16 = 0;
+  db->pCollNeededArg = pCollNeededArg;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Register a collation sequence factory callback with the database handle
+** db. Replace any previously installed collation sequence factory.
+*/
+SQLITE_API int sqlite3_collation_needed16(
+  sqlite3 *db,
+  void *pCollNeededArg,
+  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->xCollNeeded = 0;
+  db->xCollNeeded16 = xCollNeeded16;
+  db->pCollNeededArg = pCollNeededArg;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Find existing client data.
+*/
+SQLITE_API void *sqlite3_get_clientdata(sqlite3 *db, const char *zName){
+  DbClientData *p;
+  sqlite3_mutex_enter(db->mutex);
+  for(p=db->pDbData; p; p=p->pNext){
+    if( strcmp(p->zName, zName)==0 ){
+      void *pResult = p->pData;
+      sqlite3_mutex_leave(db->mutex);
+      return pResult;
+    }
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return 0;
+}
+
+/*
+** Add new client data to a database connection.
+*/
+SQLITE_API int sqlite3_set_clientdata(
+  sqlite3 *db,                   /* Attach client data to this connection */
+  const char *zName,             /* Name of the client data */
+  void *pData,                   /* The client data itself */
+  void (*xDestructor)(void*)     /* Destructor */
+){
+  DbClientData *p, **pp;
+  sqlite3_mutex_enter(db->mutex);
+  pp = &db->pDbData;
+  for(p=db->pDbData; p && strcmp(p->zName,zName); p=p->pNext){
+    pp = &p->pNext;
+  }
+  if( p ){
+    assert( p->pData!=0 );
+    if( p->xDestructor ) p->xDestructor(p->pData);
+    if( pData==0 ){
+      *pp = p->pNext;
+      sqlite3_free(p);
+      sqlite3_mutex_leave(db->mutex);
+      return SQLITE_OK;
+    }
+  }else if( pData==0 ){
+    sqlite3_mutex_leave(db->mutex);
+    return SQLITE_OK;
+  }else{
+    size_t n = strlen(zName);
+    p = sqlite3_malloc64( sizeof(DbClientData)+n+1 );
+    if( p==0 ){
+      if( xDestructor ) xDestructor(pData);
+      sqlite3_mutex_leave(db->mutex);
+      return SQLITE_NOMEM;
+    }
+    memcpy(p->zName, zName, n+1);
+    p->pNext = db->pDbData;
+    db->pDbData = p;
+  }
+  p->pData = pData;
+  p->xDestructor = xDestructor;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** This function is now an anachronism. It used to be used to recover from a
+** malloc() failure, but SQLite now does this automatically.
+*/
+SQLITE_API int sqlite3_global_recover(void){
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Test to see whether or not the database connection is in autocommit
+** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
+** by default.  Autocommit is disabled by a BEGIN statement and reenabled
+** by the next COMMIT or ROLLBACK.
+*/
+SQLITE_API int sqlite3_get_autocommit(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->autoCommit;
+}
+
+/*
+** The following routines are substitutes for constants SQLITE_CORRUPT,
+** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
+** constants.  They serve two purposes:
+**
+**   1.  Serve as a convenient place to set a breakpoint in a debugger
+**       to detect when version error conditions occurs.
+**
+**   2.  Invoke sqlite3_log() to provide the source code location where
+**       a low-level error is first detected.
+*/
+SQLITE_PRIVATE int sqlite3ReportError(int iErr, int lineno, const char *zType){
+  sqlite3_log(iErr, "%s at line %d of [%.10s]",
+              zType, lineno, 20+sqlite3_sourceid());
+  return iErr;
+}
+SQLITE_PRIVATE int sqlite3CorruptError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_CORRUPT, lineno, "database corruption");
+}
+SQLITE_PRIVATE int sqlite3MisuseError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_MISUSE, lineno, "misuse");
+}
+SQLITE_PRIVATE int sqlite3CantopenError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_CANTOPEN, lineno, "cannot open file");
+}
+#if defined(SQLITE_DEBUG) || defined(SQLITE_ENABLE_CORRUPT_PGNO)
+SQLITE_PRIVATE int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
+  char zMsg[100];
+  sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_CORRUPT, lineno, zMsg);
+}
+#endif
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3NomemError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_NOMEM, lineno, "OOM");
+}
+SQLITE_PRIVATE int sqlite3IoerrnomemError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
+}
+#endif
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** This is a convenience routine that makes sure that all thread-specific
+** data for this thread has been deallocated.
+**
+** SQLite no longer uses thread-specific data so this routine is now a
+** no-op.  It is retained for historical compatibility.
+*/
+SQLITE_API void sqlite3_thread_cleanup(void){
+}
+#endif
+
+/*
+** Return meta information about a specific column of a database table.
+** See comment in sqlite3.h (sqlite.h.in) for details.
+*/
+SQLITE_API int sqlite3_table_column_metadata(
+  sqlite3 *db,                /* Connection handle */
+  const char *zDbName,        /* Database name or NULL */
+  const char *zTableName,     /* Table name */
+  const char *zColumnName,    /* Column name */
+  char const **pzDataType,    /* OUTPUT: Declared data type */
+  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
+  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
+  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
+  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
+){
+  int rc;
+  char *zErrMsg = 0;
+  Table *pTab = 0;
+  Column *pCol = 0;
+  int iCol = 0;
+  char const *zDataType = 0;
+  char const *zCollSeq = 0;
+  int notnull = 0;
+  int primarykey = 0;
+  int autoinc = 0;
+
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+
+  /* Ensure the database schema has been loaded */
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  rc = sqlite3Init(db, &zErrMsg);
+  if( SQLITE_OK!=rc ){
+    goto error_out;
+  }
+
+  /* Locate the table in question */
+  pTab = sqlite3FindTable(db, zTableName, zDbName);
+  if( !pTab || IsView(pTab) ){
+    pTab = 0;
+    goto error_out;
+  }
+
+  /* Find the column for which info is requested */
+  if( zColumnName==0 ){
+    /* Query for existence of table only */
+  }else{
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      pCol = &pTab->aCol[iCol];
+      if( 0==sqlite3StrICmp(pCol->zCnName, zColumnName) ){
+        break;
+      }
+    }
+    if( iCol==pTab->nCol ){
+      if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
+        iCol = pTab->iPKey;
+        pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
+      }else{
+        pTab = 0;
+        goto error_out;
+      }
+    }
+  }
+
+  /* The following block stores the meta information that will be returned
+  ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
+  ** and autoinc. At this point there are two possibilities:
+  **
+  **     1. The specified column name was rowid", "oid" or "_rowid_"
+  **        and there is no explicitly declared IPK column.
+  **
+  **     2. The table is not a view and the column name identified an
+  **        explicitly declared column. Copy meta information from *pCol.
+  */
+  if( pCol ){
+    zDataType = sqlite3ColumnType(pCol,0);
+    zCollSeq = sqlite3ColumnColl(pCol);
+    notnull = pCol->notNull!=0;
+    primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
+    autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
+  }else{
+    zDataType = "INTEGER";
+    primarykey = 1;
+  }
+  if( !zCollSeq ){
+    zCollSeq = sqlite3StrBINARY;
+  }
+
+error_out:
+  sqlite3BtreeLeaveAll(db);
+
+  /* Whether the function call succeeded or failed, set the output parameters
+  ** to whatever their local counterparts contain. If an error did occur,
+  ** this has the effect of zeroing all output parameters.
+  */
+  if( pzDataType ) *pzDataType = zDataType;
+  if( pzCollSeq ) *pzCollSeq = zCollSeq;
+  if( pNotNull ) *pNotNull = notnull;
+  if( pPrimaryKey ) *pPrimaryKey = primarykey;
+  if( pAutoinc ) *pAutoinc = autoinc;
+
+  if( SQLITE_OK==rc && !pTab ){
+    sqlite3DbFree(db, zErrMsg);
+    zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
+        zColumnName);
+    rc = SQLITE_ERROR;
+  }
+  sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
+  sqlite3DbFree(db, zErrMsg);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+*/
+SQLITE_API int sqlite3_sleep(int ms){
+  sqlite3_vfs *pVfs;
+  int rc;
+  pVfs = sqlite3_vfs_find(0);
+  if( pVfs==0 ) return 0;
+
+  /* This function works in milliseconds, but the underlying OsSleep()
+  ** API uses microseconds. Hence the 1000's.
+  */
+  rc = (sqlite3OsSleep(pVfs, ms<0 ? 0 : 1000*ms)/1000);
+  return rc;
+}
+
+/*
+** Enable or disable the extended result codes.
+*/
+SQLITE_API int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->errMask = onoff ? 0xffffffff : 0xff;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Invoke the xFileControl method on a particular database.
+*/
+SQLITE_API int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
+  int rc = SQLITE_ERROR;
+  Btree *pBtree;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pBtree = sqlite3DbNameToBtree(db, zDbName);
+  if( pBtree ){
+    Pager *pPager;
+    sqlite3_file *fd;
+    sqlite3BtreeEnter(pBtree);
+    pPager = sqlite3BtreePager(pBtree);
+    assert( pPager!=0 );
+    fd = sqlite3PagerFile(pPager);
+    assert( fd!=0 );
+    if( op==SQLITE_FCNTL_FILE_POINTER ){
+      *(sqlite3_file**)pArg = fd;
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_VFS_POINTER ){
+      *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
+      *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_DATA_VERSION ){
+      *(unsigned int*)pArg = sqlite3PagerDataVersion(pPager);
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_RESERVE_BYTES ){
+      int iNew = *(int*)pArg;
+      *(int*)pArg = sqlite3BtreeGetRequestedReserve(pBtree);
+      if( iNew>=0 && iNew<=255 ){
+        sqlite3BtreeSetPageSize(pBtree, 0, iNew, 0);
+      }
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_RESET_CACHE ){
+      sqlite3BtreeClearCache(pBtree);
+      rc = SQLITE_OK;
+    }else{
+      int nSave = db->busyHandler.nBusy;
+      rc = sqlite3OsFileControl(fd, op, pArg);
+      db->busyHandler.nBusy = nSave;
+    }
+    sqlite3BtreeLeave(pBtree);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Interface to the testing logic.
+*/
+SQLITE_API int sqlite3_test_control(int op, ...){
+  int rc = 0;
+#ifdef SQLITE_UNTESTABLE
+  UNUSED_PARAMETER(op);
+#else
+  va_list ap;
+  va_start(ap, op);
+  switch( op ){
+
+    /*
+    ** Save the current state of the PRNG.
+    */
+    case SQLITE_TESTCTRL_PRNG_SAVE: {
+      sqlite3PrngSaveState();
+      break;
+    }
+
+    /*
+    ** Restore the state of the PRNG to the last state saved using
+    ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
+    ** this verb acts like PRNG_RESET.
+    */
+    case SQLITE_TESTCTRL_PRNG_RESTORE: {
+      sqlite3PrngRestoreState();
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_PRNG_SEED, int x, sqlite3 *db);
+    **
+    ** Control the seed for the pseudo-random number generator (PRNG) that
+    ** is built into SQLite.  Cases:
+    **
+    **    x!=0 && db!=0       Seed the PRNG to the current value of the
+    **                        schema cookie in the main database for db, or
+    **                        x if the schema cookie is zero.  This case
+    **                        is convenient to use with database fuzzers
+    **                        as it allows the fuzzer some control over the
+    **                        the PRNG seed.
+    **
+    **    x!=0 && db==0       Seed the PRNG to the value of x.
+    **
+    **    x==0 && db==0       Revert to default behavior of using the
+    **                        xRandomness method on the primary VFS.
+    **
+    ** This test-control also resets the PRNG so that the new seed will
+    ** be used for the next call to sqlite3_randomness().
+    */
+#ifndef SQLITE_OMIT_WSD
+    case SQLITE_TESTCTRL_PRNG_SEED: {
+      int x = va_arg(ap, int);
+      int y;
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      assert( db==0 || db->aDb[0].pSchema!=0 );
+      if( db && (y = db->aDb[0].pSchema->schema_cookie)!=0 ){ x = y; }
+      sqlite3Config.iPrngSeed = x;
+      sqlite3_randomness(0,0);
+      break;
+    }
+#endif
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_FK_NO_ACTION, sqlite3 *db, int b);
+    **
+    ** If b is true, then activate the SQLITE_FkNoAction setting.  If b is
+    ** false then clearn that setting.  If the SQLITE_FkNoAction setting is
+    ** abled, all foreign key ON DELETE and ON UPDATE actions behave as if
+    ** they were NO ACTION, regardless of how they are defined.
+    **
+    ** NB:  One must usually run "PRAGMA writable_schema=RESET" after
+    ** using this test-control, before it will take full effect.  failing
+    ** to reset the schema can result in some unexpected behavior.
+    */
+    case SQLITE_TESTCTRL_FK_NO_ACTION: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      int b = va_arg(ap, int);
+      if( b ){
+        db->flags |= SQLITE_FkNoAction;
+      }else{
+        db->flags &= ~SQLITE_FkNoAction;
+      }
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(BITVEC_TEST, size, program)
+    **
+    ** Run a test against a Bitvec object of size.  The program argument
+    ** is an array of integers that defines the test.  Return -1 on a
+    ** memory allocation error, 0 on success, or non-zero for an error.
+    ** See the sqlite3BitvecBuiltinTest() for additional information.
+    */
+    case SQLITE_TESTCTRL_BITVEC_TEST: {
+      int sz = va_arg(ap, int);
+      int *aProg = va_arg(ap, int*);
+      rc = sqlite3BitvecBuiltinTest(sz, aProg);
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(FAULT_INSTALL, xCallback)
+    **
+    ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
+    ** if xCallback is not NULL.
+    **
+    ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
+    ** is called immediately after installing the new callback and the return
+    ** value from sqlite3FaultSim(0) becomes the return from
+    ** sqlite3_test_control().
+    */
+    case SQLITE_TESTCTRL_FAULT_INSTALL: {
+      /* A bug in MSVC prevents it from understanding pointers to functions
+      ** types in the second argument to va_arg().  Work around the problem
+      ** using a typedef.
+      ** http://support.microsoft.com/kb/47961  <-- dead hyperlink
+      ** Search at http://web.archive.org/ to find the 2015-03-16 archive
+      ** of the link above to see the original text.
+      ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
+      */
+      typedef int(*sqlite3FaultFuncType)(int);
+      sqlite3GlobalConfig.xTestCallback = va_arg(ap, sqlite3FaultFuncType);
+      rc = sqlite3FaultSim(0);
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
+    **
+    ** Register hooks to call to indicate which malloc() failures
+    ** are benign.
+    */
+    case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
+      typedef void (*void_function)(void);
+      void_function xBenignBegin;
+      void_function xBenignEnd;
+      xBenignBegin = va_arg(ap, void_function);
+      xBenignEnd = va_arg(ap, void_function);
+      sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
+    **
+    ** Set the PENDING byte to the value in the argument, if X>0.
+    ** Make no changes if X==0.  Return the value of the pending byte
+    ** as it existing before this routine was called.
+    **
+    ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
+    ** an incompatible database file format.  Changing the PENDING byte
+    ** while any database connection is open results in undefined and
+    ** deleterious behavior.
+    */
+    case SQLITE_TESTCTRL_PENDING_BYTE: {
+      rc = PENDING_BYTE;
+#ifndef SQLITE_OMIT_WSD
+      {
+        unsigned int newVal = va_arg(ap, unsigned int);
+        if( newVal ) sqlite3PendingByte = newVal;
+      }
+#endif
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
+    **
+    ** This action provides a run-time test to see whether or not
+    ** assert() was enabled at compile-time.  If X is true and assert()
+    ** is enabled, then the return value is true.  If X is true and
+    ** assert() is disabled, then the return value is zero.  If X is
+    ** false and assert() is enabled, then the assertion fires and the
+    ** process aborts.  If X is false and assert() is disabled, then the
+    ** return value is zero.
+    */
+    case SQLITE_TESTCTRL_ASSERT: {
+      volatile int x = 0;
+      assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
+      rc = x;
+#if defined(SQLITE_DEBUG)
+      /* Invoke these debugging routines so that the compiler does not
+      ** issue "defined but not used" warnings. */
+      if( x==9999 ){
+        sqlite3ShowExpr(0);
+        sqlite3ShowExprList(0);
+        sqlite3ShowIdList(0);
+        sqlite3ShowSrcList(0);
+        sqlite3ShowWith(0);
+        sqlite3ShowUpsert(0);
+#ifndef SQLITE_OMIT_TRIGGER
+        sqlite3ShowTriggerStep(0);
+        sqlite3ShowTriggerStepList(0);
+        sqlite3ShowTrigger(0);
+        sqlite3ShowTriggerList(0);
+#endif
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        sqlite3ShowWindow(0);
+        sqlite3ShowWinFunc(0);
+#endif
+        sqlite3ShowSelect(0);
+      }
+#endif
+      break;
+    }
+
+
+    /*
+    **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
+    **
+    ** This action provides a run-time test to see how the ALWAYS and
+    ** NEVER macros were defined at compile-time.
+    **
+    ** The return value is ALWAYS(X) if X is true, or 0 if X is false.
+    **
+    ** The recommended test is X==2.  If the return value is 2, that means
+    ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
+    ** default setting.  If the return value is 1, then ALWAYS() is either
+    ** hard-coded to true or else it asserts if its argument is false.
+    ** The first behavior (hard-coded to true) is the case if
+    ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
+    ** behavior (assert if the argument to ALWAYS() is false) is the case if
+    ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
+    **
+    ** The run-time test procedure might look something like this:
+    **
+    **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
+    **      // ALWAYS() and NEVER() are no-op pass-through macros
+    **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
+    **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
+    **    }else{
+    **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
+    **    }
+    */
+    case SQLITE_TESTCTRL_ALWAYS: {
+      int x = va_arg(ap,int);
+      rc = x ? ALWAYS(x) : 0;
+      break;
+    }
+
+    /*
+    **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
+    **
+    ** The integer returned reveals the byte-order of the computer on which
+    ** SQLite is running:
+    **
+    **       1     big-endian,    determined at run-time
+    **      10     little-endian, determined at run-time
+    **  432101     big-endian,    determined at compile-time
+    **  123410     little-endian, determined at compile-time
+    */
+    case SQLITE_TESTCTRL_BYTEORDER: {
+      rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
+    **
+    ** Enable or disable various optimizations for testing purposes.  The
+    ** argument N is a bitmask of optimizations to be disabled.  For normal
+    ** operation N should be 0.  The idea is that a test program (like the
+    ** SQL Logic Test or SLT test module) can run the same SQL multiple times
+    ** with various optimizations disabled to verify that the same answer
+    ** is obtained in every case.
+    */
+    case SQLITE_TESTCTRL_OPTIMIZATIONS: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      db->dbOptFlags = va_arg(ap, u32);
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_GETOPT, sqlite3 *db, int *N)
+    **
+    ** Write the current optimization settings into *N.  A zero bit means that
+    ** the optimization is on, and a 1 bit means that the optimization is off.
+    */
+    case SQLITE_TESTCTRL_GETOPT: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      int *pN = va_arg(ap, int*);
+      *pN = db->dbOptFlags;
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, onoff, xAlt);
+    **
+    ** If parameter onoff is 1, subsequent calls to localtime() fail.
+    ** If 2, then invoke xAlt() instead of localtime().  If 0, normal
+    ** processing.
+    **
+    ** xAlt arguments are void pointers, but they really want to be:
+    **
+    **    int xAlt(const time_t*, struct tm*);
+    **
+    ** xAlt should write results in to struct tm object of its 2nd argument
+    ** and return zero on success, or return non-zero on failure.
+    */
+    case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
+      sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
+      if( sqlite3GlobalConfig.bLocaltimeFault==2 ){
+        typedef int(*sqlite3LocaltimeType)(const void*,void*);
+        sqlite3GlobalConfig.xAltLocaltime = va_arg(ap, sqlite3LocaltimeType);
+      }else{
+        sqlite3GlobalConfig.xAltLocaltime = 0;
+      }
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_INTERNAL_FUNCTIONS, sqlite3*);
+    **
+    ** Toggle the ability to use internal functions on or off for
+    ** the database connection given in the argument.
+    */
+    case SQLITE_TESTCTRL_INTERNAL_FUNCTIONS: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      db->mDbFlags ^= DBFLAG_InternalFunc;
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
+    **
+    ** Set or clear a flag that indicates that the database file is always well-
+    ** formed and never corrupt.  This flag is clear by default, indicating that
+    ** database files might have arbitrary corruption.  Setting the flag during
+    ** testing causes certain assert() statements in the code to be activated
+    ** that demonstrate invariants on well-formed database files.
+    */
+    case SQLITE_TESTCTRL_NEVER_CORRUPT: {
+      sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS, int);
+    **
+    ** Set or clear a flag that causes SQLite to verify that type, name,
+    ** and tbl_name fields of the sqlite_schema table.  This is normally
+    ** on, but it is sometimes useful to turn it off for testing.
+    **
+    ** 2020-07-22:  Disabling EXTRA_SCHEMA_CHECKS also disables the
+    ** verification of rootpage numbers when parsing the schema.  This
+    ** is useful to make it easier to reach strange internal error states
+    ** during testing.  The EXTRA_SCHEMA_CHECKS setting is always enabled
+    ** in production.
+    */
+    case SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS: {
+      sqlite3GlobalConfig.bExtraSchemaChecks = va_arg(ap, int);
+      break;
+    }
+
+    /* Set the threshold at which OP_Once counters reset back to zero.
+    ** By default this is 0x7ffffffe (over 2 billion), but that value is
+    ** too big to test in a reasonable amount of time, so this control is
+    ** provided to set a small and easily reachable reset value.
+    */
+    case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
+      sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
+    **
+    ** Set the VDBE coverage callback function to xCallback with context
+    ** pointer ptr.
+    */
+    case SQLITE_TESTCTRL_VDBE_COVERAGE: {
+#ifdef SQLITE_VDBE_COVERAGE
+      typedef void (*branch_callback)(void*,unsigned int,
+                                      unsigned char,unsigned char);
+      sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
+      sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
+#endif
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
+    case SQLITE_TESTCTRL_SORTER_MMAP: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      db->nMaxSorterMmap = va_arg(ap, int);
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
+    **
+    ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
+    ** not.
+    */
+    case SQLITE_TESTCTRL_ISINIT: {
+      if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
+    **
+    ** This test control is used to create imposter tables.  "db" is a pointer
+    ** to the database connection.  dbName is the database name (ex: "main" or
+    ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
+    ** or off.  "tnum" is the root page of the b-tree to which the imposter
+    ** table should connect.
+    **
+    ** Enable imposter mode only when the schema has already been parsed.  Then
+    ** run a single CREATE TABLE statement to construct the imposter table in
+    ** the parsed schema.  Then turn imposter mode back off again.
+    **
+    ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
+    ** the schema to be reparsed the next time it is needed.  This has the
+    ** effect of erasing all imposter tables.
+    */
+    case SQLITE_TESTCTRL_IMPOSTER: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      int iDb;
+      sqlite3_mutex_enter(db->mutex);
+      iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
+      if( iDb>=0 ){
+        db->init.iDb = iDb;
+        db->init.busy = db->init.imposterTable = va_arg(ap,int);
+        db->init.newTnum = va_arg(ap,int);
+        if( db->init.busy==0 && db->init.newTnum>0 ){
+          sqlite3ResetAllSchemasOfConnection(db);
+        }
+      }
+      sqlite3_mutex_leave(db->mutex);
+      break;
+    }
+
+#if defined(YYCOVERAGE)
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_PARSER_COVERAGE, FILE *out)
+    **
+    ** This test control (only available when SQLite is compiled with
+    ** -DYYCOVERAGE) writes a report onto "out" that shows all
+    ** state/lookahead combinations in the parser state machine
+    ** which are never exercised.  If any state is missed, make the
+    ** return code SQLITE_ERROR.
+    */
+    case SQLITE_TESTCTRL_PARSER_COVERAGE: {
+      FILE *out = va_arg(ap, FILE*);
+      if( sqlite3ParserCoverage(out) ) rc = SQLITE_ERROR;
+      break;
+    }
+#endif /* defined(YYCOVERAGE) */
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_RESULT_INTREAL, sqlite3_context*);
+    **
+    ** This test-control causes the most recent sqlite3_result_int64() value
+    ** to be interpreted as a MEM_IntReal instead of as an MEM_Int.  Normally,
+    ** MEM_IntReal values only arise during an INSERT operation of integer
+    ** values into a REAL column, so they can be challenging to test.  This
+    ** test-control enables us to write an intreal() SQL function that can
+    ** inject an intreal() value at arbitrary places in an SQL statement,
+    ** for testing purposes.
+    */
+    case SQLITE_TESTCTRL_RESULT_INTREAL: {
+      sqlite3_context *pCtx = va_arg(ap, sqlite3_context*);
+      sqlite3ResultIntReal(pCtx);
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_SEEK_COUNT,
+    **    sqlite3 *db,    // Database connection
+    **    u64 *pnSeek     // Write seek count here
+    **  );
+    **
+    ** This test-control queries the seek-counter on the "main" database
+    ** file.  The seek-counter is written into *pnSeek and is then reset.
+    ** The seek-count is only available if compiled with SQLITE_DEBUG.
+    */
+    case SQLITE_TESTCTRL_SEEK_COUNT: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      u64 *pn = va_arg(ap, sqlite3_uint64*);
+      *pn = sqlite3BtreeSeekCount(db->aDb->pBt);
+      (void)db;  /* Silence harmless unused variable warning */
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_TRACEFLAGS, op, ptr)
+    **
+    **  "ptr" is a pointer to a u32.
+    **
+    **   op==0       Store the current sqlite3TreeTrace in *ptr
+    **   op==1       Set sqlite3TreeTrace to the value *ptr
+    **   op==2       Store the current sqlite3WhereTrace in *ptr
+    **   op==3       Set sqlite3WhereTrace to the value *ptr
+    */
+    case SQLITE_TESTCTRL_TRACEFLAGS: {
+       int opTrace = va_arg(ap, int);
+       u32 *ptr = va_arg(ap, u32*);
+       switch( opTrace ){
+         case 0:   *ptr = sqlite3TreeTrace;      break;
+         case 1:   sqlite3TreeTrace = *ptr;      break;
+         case 2:   *ptr = sqlite3WhereTrace;     break;
+         case 3:   sqlite3WhereTrace = *ptr;     break;
+       }
+       break;
+    }
+
+    /* sqlite3_test_control(SQLITE_TESTCTRL_LOGEST,
+    **      double fIn,     // Input value
+    **      int *pLogEst,   // sqlite3LogEstFromDouble(fIn)
+    **      u64 *pInt,      // sqlite3LogEstToInt(*pLogEst)
+    **      int *pLogEst2   // sqlite3LogEst(*pInt)
+    ** );
+    **
+    ** Test access for the LogEst conversion routines.
+    */
+    case SQLITE_TESTCTRL_LOGEST: {
+      double rIn = va_arg(ap, double);
+      LogEst rLogEst = sqlite3LogEstFromDouble(rIn);
+      int *pI1 = va_arg(ap,int*);
+      u64 *pU64 = va_arg(ap,u64*);
+      int *pI2 = va_arg(ap,int*);
+      *pI1 = rLogEst;
+      *pU64 = sqlite3LogEstToInt(rLogEst);
+      *pI2 = sqlite3LogEst(*pU64);
+      break;
+    }
+
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_WSD)
+    /* sqlite3_test_control(SQLITE_TESTCTRL_TUNE, id, *piValue)
+    **
+    ** If "id" is an integer between 1 and SQLITE_NTUNE then set the value
+    ** of the id-th tuning parameter to *piValue.  If "id" is between -1
+    ** and -SQLITE_NTUNE, then write the current value of the (-id)-th
+    ** tuning parameter into *piValue.
+    **
+    ** Tuning parameters are for use during transient development builds,
+    ** to help find the best values for constants in the query planner.
+    ** Access tuning parameters using the Tuning(ID) macro.  Set the
+    ** parameters in the CLI using ".testctrl tune ID VALUE".
+    **
+    ** Transient use only.  Tuning parameters should not be used in
+    ** checked-in code.
+    */
+    case SQLITE_TESTCTRL_TUNE: {
+      int id = va_arg(ap, int);
+      int *piValue = va_arg(ap, int*);
+      if( id>0 && id<=SQLITE_NTUNE ){
+        Tuning(id) = *piValue;
+      }else if( id<0 && id>=-SQLITE_NTUNE ){
+        *piValue = Tuning(-id);
+      }else{
+        rc = SQLITE_NOTFOUND;
+      }
+      break;
+    }
+#endif
+
+    /* sqlite3_test_control(SQLITE_TESTCTRL_JSON_SELFCHECK, &onOff);
+    **
+    ** Activate or deactivate validation of JSONB that is generated from
+    ** text.  Off by default, as the validation is slow.  Validation is
+    ** only available if compiled using SQLITE_DEBUG.
+    **
+    ** If onOff is initially 1, then turn it on.  If onOff is initially
+    ** off, turn it off.  If onOff is initially -1, then change onOff
+    ** to be the current setting.
+    */
+    case SQLITE_TESTCTRL_JSON_SELFCHECK: {
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_WSD)
+      int *pOnOff = va_arg(ap, int*);
+      if( *pOnOff<0 ){
+        *pOnOff = sqlite3Config.bJsonSelfcheck;
+      }else{
+        sqlite3Config.bJsonSelfcheck = (u8)((*pOnOff)&0xff);
+      }
+#endif
+      break;
+    }
+  }
+  va_end(ap);
+#endif /* SQLITE_UNTESTABLE */
+  return rc;
+}
+
+/*
+** The Pager stores the Database filename, Journal filename, and WAL filename
+** consecutively in memory, in that order.  The database filename is prefixed
+** by four zero bytes.  Locate the start of the database filename by searching
+** backwards for the first byte following four consecutive zero bytes.
+**
+** This only works if the filename passed in was obtained from the Pager.
+*/
+static const char *databaseName(const char *zName){
+  while( zName[-1]!=0 || zName[-2]!=0 || zName[-3]!=0 || zName[-4]!=0 ){
+    zName--;
+  }
+  return zName;
+}
+
+/*
+** Append text z[] to the end of p[].  Return a pointer to the first
+** character after then zero terminator on the new text in p[].
+*/
+static char *appendText(char *p, const char *z){
+  size_t n = strlen(z);
+  memcpy(p, z, n+1);
+  return p+n+1;
+}
+
+/*
+** Allocate memory to hold names for a database, journal file, WAL file,
+** and query parameters.  The pointer returned is valid for use by
+** sqlite3_filename_database() and sqlite3_uri_parameter() and related
+** functions.
+**
+** Memory layout must be compatible with that generated by the pager
+** and expected by sqlite3_uri_parameter() and databaseName().
+*/
+SQLITE_API const char *sqlite3_create_filename(
+  const char *zDatabase,
+  const char *zJournal,
+  const char *zWal,
+  int nParam,
+  const char **azParam
+){
+  sqlite3_int64 nByte;
+  int i;
+  char *pResult, *p;
+  nByte = strlen(zDatabase) + strlen(zJournal) + strlen(zWal) + 10;
+  for(i=0; i<nParam*2; i++){
+    nByte += strlen(azParam[i])+1;
+  }
+  pResult = p = sqlite3_malloc64( nByte );
+  if( p==0 ) return 0;
+  memset(p, 0, 4);
+  p += 4;
+  p = appendText(p, zDatabase);
+  for(i=0; i<nParam*2; i++){
+    p = appendText(p, azParam[i]);
+  }
+  *(p++) = 0;
+  p = appendText(p, zJournal);
+  p = appendText(p, zWal);
+  *(p++) = 0;
+  *(p++) = 0;
+  assert( (sqlite3_int64)(p - pResult)==nByte );
+  return pResult + 4;
+}
+
+/*
+** Free memory obtained from sqlite3_create_filename().  It is a severe
+** error to call this routine with any parameter other than a pointer
+** previously obtained from sqlite3_create_filename() or a NULL pointer.
+*/
+SQLITE_API void sqlite3_free_filename(const char *p){
+  if( p==0 ) return;
+  p = databaseName(p);
+  sqlite3_free((char*)p - 4);
+}
+
+
+/*
+** This is a utility routine, useful to VFS implementations, that checks
+** to see if a database file was a URI that contained a specific query
+** parameter, and if so obtains the value of the query parameter.
+**
+** The zFilename argument is the filename pointer passed into the xOpen()
+** method of a VFS implementation.  The zParam argument is the name of the
+** query parameter we seek.  This routine returns the value of the zParam
+** parameter if it exists.  If the parameter does not exist, this routine
+** returns a NULL pointer.
+*/
+SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
+  if( zFilename==0 || zParam==0 ) return 0;
+  zFilename = databaseName(zFilename);
+  return uriParameter(zFilename, zParam);
+}
+
+/*
+** Return a pointer to the name of Nth query parameter of the filename.
+*/
+SQLITE_API const char *sqlite3_uri_key(const char *zFilename, int N){
+  if( zFilename==0 || N<0 ) return 0;
+  zFilename = databaseName(zFilename);
+  zFilename += sqlite3Strlen30(zFilename) + 1;
+  while( ALWAYS(zFilename) && zFilename[0] && (N--)>0 ){
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+  }
+  return zFilename[0] ? zFilename : 0;
+}
+
+/*
+** Return a boolean value for a query parameter.
+*/
+SQLITE_API int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
+  const char *z = sqlite3_uri_parameter(zFilename, zParam);
+  bDflt = bDflt!=0;
+  return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
+}
+
+/*
+** Return a 64-bit integer value for a query parameter.
+*/
+SQLITE_API sqlite3_int64 sqlite3_uri_int64(
+  const char *zFilename,    /* Filename as passed to xOpen */
+  const char *zParam,       /* URI parameter sought */
+  sqlite3_int64 bDflt       /* return if parameter is missing */
+){
+  const char *z = sqlite3_uri_parameter(zFilename, zParam);
+  sqlite3_int64 v;
+  if( z && sqlite3DecOrHexToI64(z, &v)==0 ){
+    bDflt = v;
+  }
+  return bDflt;
+}
+
+/*
+** Translate a filename that was handed to a VFS routine into the corresponding
+** database, journal, or WAL file.
+**
+** It is an error to pass this routine a filename string that was not
+** passed into the VFS from the SQLite core.  Doing so is similar to
+** passing free() a pointer that was not obtained from malloc() - it is
+** an error that we cannot easily detect but that will likely cause memory
+** corruption.
+*/
+SQLITE_API const char *sqlite3_filename_database(const char *zFilename){
+  if( zFilename==0 ) return 0;
+  return databaseName(zFilename);
+}
+SQLITE_API const char *sqlite3_filename_journal(const char *zFilename){
+  if( zFilename==0 ) return 0;
+  zFilename = databaseName(zFilename);
+  zFilename += sqlite3Strlen30(zFilename) + 1;
+  while( ALWAYS(zFilename) && zFilename[0] ){
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+  }
+  return zFilename + 1;
+}
+SQLITE_API const char *sqlite3_filename_wal(const char *zFilename){
+#ifdef SQLITE_OMIT_WAL
+  return 0;
+#else
+  zFilename = sqlite3_filename_journal(zFilename);
+  if( zFilename ) zFilename += sqlite3Strlen30(zFilename) + 1;
+  return zFilename;
+#endif
+}
+
+/*
+** Return the Btree pointer identified by zDbName.  Return NULL if not found.
+*/
+SQLITE_PRIVATE Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
+  int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
+  return iDb<0 ? 0 : db->aDb[iDb].pBt;
+}
+
+/*
+** Return the name of the N-th database schema.  Return NULL if N is out
+** of range.
+*/
+SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  if( N<0 || N>=db->nDb ){
+    return 0;
+  }else{
+    return db->aDb[N].zDbSName;
+  }
+}
+
+/*
+** Return the filename of the database associated with a database
+** connection.
+*/
+SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
+  Btree *pBt;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  pBt = sqlite3DbNameToBtree(db, zDbName);
+  return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
+}
+
+/*
+** Return 1 if database is read-only or 0 if read/write.  Return -1 if
+** no such database exists.
+*/
+SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
+  Btree *pBt;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return -1;
+  }
+#endif
+  pBt = sqlite3DbNameToBtree(db, zDbName);
+  return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
+}
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+/*
+** Obtain a snapshot handle for the snapshot of database zDb currently
+** being read by handle db.
+*/
+SQLITE_API int sqlite3_snapshot_get(
+  sqlite3 *db,
+  const char *zDb,
+  sqlite3_snapshot **ppSnapshot
+){
+  int rc = SQLITE_ERROR;
+#ifndef SQLITE_OMIT_WAL
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+
+  if( db->autoCommit==0 ){
+    int iDb = sqlite3FindDbName(db, zDb);
+    if( iDb==0 || iDb>1 ){
+      Btree *pBt = db->aDb[iDb].pBt;
+      if( SQLITE_TXN_WRITE!=sqlite3BtreeTxnState(pBt) ){
+        Pager *pPager = sqlite3BtreePager(pBt);
+        i64 dummy = 0;
+        sqlite3PagerSnapshotOpen(pPager, (sqlite3_snapshot*)&dummy);
+        rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
+        sqlite3PagerSnapshotOpen(pPager, 0);
+        if( rc==SQLITE_OK ){
+          rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
+        }
+      }
+    }
+  }
+
+  sqlite3_mutex_leave(db->mutex);
+#endif   /* SQLITE_OMIT_WAL */
+  return rc;
+}
+
+/*
+** Open a read-transaction on the snapshot identified by pSnapshot.
+*/
+SQLITE_API int sqlite3_snapshot_open(
+  sqlite3 *db,
+  const char *zDb,
+  sqlite3_snapshot *pSnapshot
+){
+  int rc = SQLITE_ERROR;
+#ifndef SQLITE_OMIT_WAL
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( db->autoCommit==0 ){
+    int iDb;
+    iDb = sqlite3FindDbName(db, zDb);
+    if( iDb==0 || iDb>1 ){
+      Btree *pBt = db->aDb[iDb].pBt;
+      if( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_WRITE ){
+        Pager *pPager = sqlite3BtreePager(pBt);
+        int bUnlock = 0;
+        if( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_NONE ){
+          if( db->nVdbeActive==0 ){
+            rc = sqlite3PagerSnapshotCheck(pPager, pSnapshot);
+            if( rc==SQLITE_OK ){
+              bUnlock = 1;
+              rc = sqlite3BtreeCommit(pBt);
+            }
+          }
+        }else{
+          rc = SQLITE_OK;
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3PagerSnapshotOpen(pPager, pSnapshot);
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
+          sqlite3PagerSnapshotOpen(pPager, 0);
+        }
+        if( bUnlock ){
+          sqlite3PagerSnapshotUnlock(pPager);
+        }
+      }
+    }
+  }
+
+  sqlite3_mutex_leave(db->mutex);
+#endif   /* SQLITE_OMIT_WAL */
+  return rc;
+}
+
+/*
+** Recover as many snapshots as possible from the wal file associated with
+** schema zDb of database db.
+*/
+SQLITE_API int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
+  int rc = SQLITE_ERROR;
+#ifndef SQLITE_OMIT_WAL
+  int iDb;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+
+  sqlite3_mutex_enter(db->mutex);
+  iDb = sqlite3FindDbName(db, zDb);
+  if( iDb==0 || iDb>1 ){
+    Btree *pBt = db->aDb[iDb].pBt;
+    if( SQLITE_TXN_NONE==sqlite3BtreeTxnState(pBt) ){
+      rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
+        sqlite3BtreeCommit(pBt);
+      }
+    }
+  }
+  sqlite3_mutex_leave(db->mutex);
+#endif   /* SQLITE_OMIT_WAL */
+  return rc;
+}
+
+/*
+** Free a snapshot handle obtained from sqlite3_snapshot_get().
+*/
+SQLITE_API void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
+  sqlite3_free(pSnapshot);
+}
+#endif /* SQLITE_ENABLE_SNAPSHOT */
+
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+/*
+** Given the name of a compile-time option, return true if that option
+** was used and false if not.
+**
+** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
+** is not required for a match.
+*/
+SQLITE_API int sqlite3_compileoption_used(const char *zOptName){
+  int i, n;
+  int nOpt;
+  const char **azCompileOpt;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zOptName==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+
+  azCompileOpt = sqlite3CompileOptions(&nOpt);
+
+  if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
+  n = sqlite3Strlen30(zOptName);
+
+  /* Since nOpt is normally in single digits, a linear search is
+  ** adequate. No need for a binary search. */
+  for(i=0; i<nOpt; i++){
+    if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
+     && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Return the N-th compile-time option string.  If N is out of range,
+** return a NULL pointer.
+*/
+SQLITE_API const char *sqlite3_compileoption_get(int N){
+  int nOpt;
+  const char **azCompileOpt;
+  azCompileOpt = sqlite3CompileOptions(&nOpt);
+  if( N>=0 && N<nOpt ){
+    return azCompileOpt[N];
+  }
+  return 0;
+}
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/************** End of main.c ************************************************/
+/************** Begin file notify.c ******************************************/
+/*
+** 2009 March 3
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the implementation of the sqlite3_unlock_notify()
+** API method and its associated functionality.
+*/
+/* #include "sqliteInt.h" */
+/* #include "btreeInt.h" */
+
+/* Omit this entire file if SQLITE_ENABLE_UNLOCK_NOTIFY is not defined. */
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+
+/*
+** Public interfaces:
+**
+**   sqlite3ConnectionBlocked()
+**   sqlite3ConnectionUnlocked()
+**   sqlite3ConnectionClosed()
+**   sqlite3_unlock_notify()
+*/
+
+#define assertMutexHeld() \
+  assert( sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN)) )
+
+/*
+** Head of a linked list of all sqlite3 objects created by this process
+** for which either sqlite3.pBlockingConnection or sqlite3.pUnlockConnection
+** is not NULL. This variable may only accessed while the STATIC_MAIN
+** mutex is held.
+*/
+static sqlite3 *SQLITE_WSD sqlite3BlockedList = 0;
+
+#ifndef NDEBUG
+/*
+** This function is a complex assert() that verifies the following
+** properties of the blocked connections list:
+**
+**   1) Each entry in the list has a non-NULL value for either
+**      pUnlockConnection or pBlockingConnection, or both.
+**
+**   2) All entries in the list that share a common value for
+**      xUnlockNotify are grouped together.
+**
+**   3) If the argument db is not NULL, then none of the entries in the
+**      blocked connections list have pUnlockConnection or pBlockingConnection
+**      set to db. This is used when closing connection db.
+*/
+static void checkListProperties(sqlite3 *db){
+  sqlite3 *p;
+  for(p=sqlite3BlockedList; p; p=p->pNextBlocked){
+    int seen = 0;
+    sqlite3 *p2;
+
+    /* Verify property (1) */
+    assert( p->pUnlockConnection || p->pBlockingConnection );
+
+    /* Verify property (2) */
+    for(p2=sqlite3BlockedList; p2!=p; p2=p2->pNextBlocked){
+      if( p2->xUnlockNotify==p->xUnlockNotify ) seen = 1;
+      assert( p2->xUnlockNotify==p->xUnlockNotify || !seen );
+      assert( db==0 || p->pUnlockConnection!=db );
+      assert( db==0 || p->pBlockingConnection!=db );
+    }
+  }
+}
+#else
+# define checkListProperties(x)
+#endif
+
+/*
+** Remove connection db from the blocked connections list. If connection
+** db is not currently a part of the list, this function is a no-op.
+*/
+static void removeFromBlockedList(sqlite3 *db){
+  sqlite3 **pp;
+  assertMutexHeld();
+  for(pp=&sqlite3BlockedList; *pp; pp = &(*pp)->pNextBlocked){
+    if( *pp==db ){
+      *pp = (*pp)->pNextBlocked;
+      break;
+    }
+  }
+}
+
+/*
+** Add connection db to the blocked connections list. It is assumed
+** that it is not already a part of the list.
+*/
+static void addToBlockedList(sqlite3 *db){
+  sqlite3 **pp;
+  assertMutexHeld();
+  for(
+    pp=&sqlite3BlockedList;
+    *pp && (*pp)->xUnlockNotify!=db->xUnlockNotify;
+    pp=&(*pp)->pNextBlocked
+  );
+  db->pNextBlocked = *pp;
+  *pp = db;
+}
+
+/*
+** Obtain the STATIC_MAIN mutex.
+*/
+static void enterMutex(void){
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN));
+  checkListProperties(0);
+}
+
+/*
+** Release the STATIC_MAIN mutex.
+*/
+static void leaveMutex(void){
+  assertMutexHeld();
+  checkListProperties(0);
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN));
+}
+
+/*
+** Register an unlock-notify callback.
+**
+** This is called after connection "db" has attempted some operation
+** but has received an SQLITE_LOCKED error because another connection
+** (call it pOther) in the same process was busy using the same shared
+** cache.  pOther is found by looking at db->pBlockingConnection.
+**
+** If there is no blocking connection, the callback is invoked immediately,
+** before this routine returns.
+**
+** If pOther is already blocked on db, then report SQLITE_LOCKED, to indicate
+** a deadlock.
+**
+** Otherwise, make arrangements to invoke xNotify when pOther drops
+** its locks.
+**
+** Each call to this routine overrides any prior callbacks registered
+** on the same "db".  If xNotify==0 then any prior callbacks are immediately
+** cancelled.
+*/
+SQLITE_API int sqlite3_unlock_notify(
+  sqlite3 *db,
+  void (*xNotify)(void **, int),
+  void *pArg
+){
+  int rc = SQLITE_OK;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  enterMutex();
+
+  if( xNotify==0 ){
+    removeFromBlockedList(db);
+    db->pBlockingConnection = 0;
+    db->pUnlockConnection = 0;
+    db->xUnlockNotify = 0;
+    db->pUnlockArg = 0;
+  }else if( 0==db->pBlockingConnection ){
+    /* The blocking transaction has been concluded. Or there never was a
+    ** blocking transaction. In either case, invoke the notify callback
+    ** immediately.
+    */
+    xNotify(&pArg, 1);
+  }else{
+    sqlite3 *p;
+
+    for(p=db->pBlockingConnection; p && p!=db; p=p->pUnlockConnection){}
+    if( p ){
+      rc = SQLITE_LOCKED;              /* Deadlock detected. */
+    }else{
+      db->pUnlockConnection = db->pBlockingConnection;
+      db->xUnlockNotify = xNotify;
+      db->pUnlockArg = pArg;
+      removeFromBlockedList(db);
+      addToBlockedList(db);
+    }
+  }
+
+  leaveMutex();
+  assert( !db->mallocFailed );
+  sqlite3ErrorWithMsg(db, rc, (rc?"database is deadlocked":0));
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** This function is called while stepping or preparing a statement
+** associated with connection db. The operation will return SQLITE_LOCKED
+** to the user because it requires a lock that will not be available
+** until connection pBlocker concludes its current transaction.
+*/
+SQLITE_PRIVATE void sqlite3ConnectionBlocked(sqlite3 *db, sqlite3 *pBlocker){
+  enterMutex();
+  if( db->pBlockingConnection==0 && db->pUnlockConnection==0 ){
+    addToBlockedList(db);
+  }
+  db->pBlockingConnection = pBlocker;
+  leaveMutex();
+}
+
+/*
+** This function is called when
+** the transaction opened by database db has just finished. Locks held
+** by database connection db have been released.
+**
+** This function loops through each entry in the blocked connections
+** list and does the following:
+**
+**   1) If the sqlite3.pBlockingConnection member of a list entry is
+**      set to db, then set pBlockingConnection=0.
+**
+**   2) If the sqlite3.pUnlockConnection member of a list entry is
+**      set to db, then invoke the configured unlock-notify callback and
+**      set pUnlockConnection=0.
+**
+**   3) If the two steps above mean that pBlockingConnection==0 and
+**      pUnlockConnection==0, remove the entry from the blocked connections
+**      list.
+*/
+SQLITE_PRIVATE void sqlite3ConnectionUnlocked(sqlite3 *db){
+  void (*xUnlockNotify)(void **, int) = 0; /* Unlock-notify cb to invoke */
+  int nArg = 0;                            /* Number of entries in aArg[] */
+  sqlite3 **pp;                            /* Iterator variable */
+  void **aArg;               /* Arguments to the unlock callback */
+  void **aDyn = 0;           /* Dynamically allocated space for aArg[] */
+  void *aStatic[16];         /* Starter space for aArg[].  No malloc required */
+
+  aArg = aStatic;
+  enterMutex();         /* Enter STATIC_MAIN mutex */
+
+  /* This loop runs once for each entry in the blocked-connections list. */
+  for(pp=&sqlite3BlockedList; *pp; /* no-op */ ){
+    sqlite3 *p = *pp;
+
+    /* Step 1. */
+    if( p->pBlockingConnection==db ){
+      p->pBlockingConnection = 0;
+    }
+
+    /* Step 2. */
+    if( p->pUnlockConnection==db ){
+      assert( p->xUnlockNotify );
+      if( p->xUnlockNotify!=xUnlockNotify && nArg!=0 ){
+        xUnlockNotify(aArg, nArg);
+        nArg = 0;
+      }
+
+      sqlite3BeginBenignMalloc();
+      assert( aArg==aDyn || (aDyn==0 && aArg==aStatic) );
+      assert( nArg<=(int)ArraySize(aStatic) || aArg==aDyn );
+      if( (!aDyn && nArg==(int)ArraySize(aStatic))
+       || (aDyn && nArg==(int)(sqlite3MallocSize(aDyn)/sizeof(void*)))
+      ){
+        /* The aArg[] array needs to grow. */
+        void **pNew = (void **)sqlite3Malloc(nArg*sizeof(void *)*2);
+        if( pNew ){
+          memcpy(pNew, aArg, nArg*sizeof(void *));
+          sqlite3_free(aDyn);
+          aDyn = aArg = pNew;
+        }else{
+          /* This occurs when the array of context pointers that need to
+          ** be passed to the unlock-notify callback is larger than the
+          ** aStatic[] array allocated on the stack and the attempt to
+          ** allocate a larger array from the heap has failed.
+          **
+          ** This is a difficult situation to handle. Returning an error
+          ** code to the caller is insufficient, as even if an error code
+          ** is returned the transaction on connection db will still be
+          ** closed and the unlock-notify callbacks on blocked connections
+          ** will go unissued. This might cause the application to wait
+          ** indefinitely for an unlock-notify callback that will never
+          ** arrive.
+          **
+          ** Instead, invoke the unlock-notify callback with the context
+          ** array already accumulated. We can then clear the array and
+          ** begin accumulating any further context pointers without
+          ** requiring any dynamic allocation. This is sub-optimal because
+          ** it means that instead of one callback with a large array of
+          ** context pointers the application will receive two or more
+          ** callbacks with smaller arrays of context pointers, which will
+          ** reduce the applications ability to prioritize multiple
+          ** connections. But it is the best that can be done under the
+          ** circumstances.
+          */
+          xUnlockNotify(aArg, nArg);
+          nArg = 0;
+        }
+      }
+      sqlite3EndBenignMalloc();
+
+      aArg[nArg++] = p->pUnlockArg;
+      xUnlockNotify = p->xUnlockNotify;
+      p->pUnlockConnection = 0;
+      p->xUnlockNotify = 0;
+      p->pUnlockArg = 0;
+    }
+
+    /* Step 3. */
+    if( p->pBlockingConnection==0 && p->pUnlockConnection==0 ){
+      /* Remove connection p from the blocked connections list. */
+      *pp = p->pNextBlocked;
+      p->pNextBlocked = 0;
+    }else{
+      pp = &p->pNextBlocked;
+    }
+  }
+
+  if( nArg!=0 ){
+    xUnlockNotify(aArg, nArg);
+  }
+  sqlite3_free(aDyn);
+  leaveMutex();         /* Leave STATIC_MAIN mutex */
+}
+
+/*
+** This is called when the database connection passed as an argument is
+** being closed. The connection is removed from the blocked list.
+*/
+SQLITE_PRIVATE void sqlite3ConnectionClosed(sqlite3 *db){
+  sqlite3ConnectionUnlocked(db);
+  enterMutex();
+  removeFromBlockedList(db);
+  checkListProperties(db);
+  leaveMutex();
+}
+#endif
+
+/************** End of notify.c **********************************************/
+/************** Begin file fts3.c ********************************************/
+/*
+** 2006 Oct 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is an SQLite module implementing full-text search.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+
+/* The full-text index is stored in a series of b+tree (-like)
+** structures called segments which map terms to doclists.  The
+** structures are like b+trees in layout, but are constructed from the
+** bottom up in optimal fashion and are not updatable.  Since trees
+** are built from the bottom up, things will be described from the
+** bottom up.
+**
+**
+**** Varints ****
+** The basic unit of encoding is a variable-length integer called a
+** varint.  We encode variable-length integers in little-endian order
+** using seven bits * per byte as follows:
+**
+** KEY:
+**         A = 0xxxxxxx    7 bits of data and one flag bit
+**         B = 1xxxxxxx    7 bits of data and one flag bit
+**
+**  7 bits - A
+** 14 bits - BA
+** 21 bits - BBA
+** and so on.
+**
+** This is similar in concept to how sqlite encodes "varints" but
+** the encoding is not the same.  SQLite varints are big-endian
+** are are limited to 9 bytes in length whereas FTS3 varints are
+** little-endian and can be up to 10 bytes in length (in theory).
+**
+** Example encodings:
+**
+**     1:    0x01
+**   127:    0x7f
+**   128:    0x81 0x00
+**
+**
+**** Document lists ****
+** A doclist (document list) holds a docid-sorted list of hits for a
+** given term.  Doclists hold docids and associated token positions.
+** A docid is the unique integer identifier for a single document.
+** A position is the index of a word within the document.  The first
+** word of the document has a position of 0.
+**
+** FTS3 used to optionally store character offsets using a compile-time
+** option.  But that functionality is no longer supported.
+**
+** A doclist is stored like this:
+**
+** array {
+**   varint docid;          (delta from previous doclist)
+**   array {                (position list for column 0)
+**     varint position;     (2 more than the delta from previous position)
+**   }
+**   array {
+**     varint POS_COLUMN;   (marks start of position list for new column)
+**     varint column;       (index of new column)
+**     array {
+**       varint position;   (2 more than the delta from previous position)
+**     }
+**   }
+**   varint POS_END;        (marks end of positions for this document.
+** }
+**
+** Here, array { X } means zero or more occurrences of X, adjacent in
+** memory.  A "position" is an index of a token in the token stream
+** generated by the tokenizer. Note that POS_END and POS_COLUMN occur
+** in the same logical place as the position element, and act as sentinals
+** ending a position list array.  POS_END is 0.  POS_COLUMN is 1.
+** The positions numbers are not stored literally but rather as two more
+** than the difference from the prior position, or the just the position plus
+** 2 for the first position.  Example:
+**
+**   label:       A B C D E  F  G H   I  J K
+**   value:     123 5 9 1 1 14 35 0 234 72 0
+**
+** The 123 value is the first docid.  For column zero in this document
+** there are two matches at positions 3 and 10 (5-2 and 9-2+3).  The 1
+** at D signals the start of a new column; the 1 at E indicates that the
+** new column is column number 1.  There are two positions at 12 and 45
+** (14-2 and 35-2+12).  The 0 at H indicate the end-of-document.  The
+** 234 at I is the delta to next docid (357).  It has one position 70
+** (72-2) and then terminates with the 0 at K.
+**
+** A "position-list" is the list of positions for multiple columns for
+** a single docid.  A "column-list" is the set of positions for a single
+** column.  Hence, a position-list consists of one or more column-lists,
+** a document record consists of a docid followed by a position-list and
+** a doclist consists of one or more document records.
+**
+** A bare doclist omits the position information, becoming an
+** array of varint-encoded docids.
+**
+**** Segment leaf nodes ****
+** Segment leaf nodes store terms and doclists, ordered by term.  Leaf
+** nodes are written using LeafWriter, and read using LeafReader (to
+** iterate through a single leaf node's data) and LeavesReader (to
+** iterate through a segment's entire leaf layer).  Leaf nodes have
+** the format:
+**
+** varint iHeight;             (height from leaf level, always 0)
+** varint nTerm;               (length of first term)
+** char pTerm[nTerm];          (content of first term)
+** varint nDoclist;            (length of term's associated doclist)
+** char pDoclist[nDoclist];    (content of doclist)
+** array {
+**                             (further terms are delta-encoded)
+**   varint nPrefix;           (length of prefix shared with previous term)
+**   varint nSuffix;           (length of unshared suffix)
+**   char pTermSuffix[nSuffix];(unshared suffix of next term)
+**   varint nDoclist;          (length of term's associated doclist)
+**   char pDoclist[nDoclist];  (content of doclist)
+** }
+**
+** Here, array { X } means zero or more occurrences of X, adjacent in
+** memory.
+**
+** Leaf nodes are broken into blocks which are stored contiguously in
+** the %_segments table in sorted order.  This means that when the end
+** of a node is reached, the next term is in the node with the next
+** greater node id.
+**
+** New data is spilled to a new leaf node when the current node
+** exceeds LEAF_MAX bytes (default 2048).  New data which itself is
+** larger than STANDALONE_MIN (default 1024) is placed in a standalone
+** node (a leaf node with a single term and doclist).  The goal of
+** these settings is to pack together groups of small doclists while
+** making it efficient to directly access large doclists.  The
+** assumption is that large doclists represent terms which are more
+** likely to be query targets.
+**
+** TODO(shess) It may be useful for blocking decisions to be more
+** dynamic.  For instance, it may make more sense to have a 2.5k leaf
+** node rather than splitting into 2k and .5k nodes.  My intuition is
+** that this might extend through 2x or 4x the pagesize.
+**
+**
+**** Segment interior nodes ****
+** Segment interior nodes store blockids for subtree nodes and terms
+** to describe what data is stored by the each subtree.  Interior
+** nodes are written using InteriorWriter, and read using
+** InteriorReader.  InteriorWriters are created as needed when
+** SegmentWriter creates new leaf nodes, or when an interior node
+** itself grows too big and must be split.  The format of interior
+** nodes:
+**
+** varint iHeight;           (height from leaf level, always >0)
+** varint iBlockid;          (block id of node's leftmost subtree)
+** optional {
+**   varint nTerm;           (length of first term)
+**   char pTerm[nTerm];      (content of first term)
+**   array {
+**                                (further terms are delta-encoded)
+**     varint nPrefix;            (length of shared prefix with previous term)
+**     varint nSuffix;            (length of unshared suffix)
+**     char pTermSuffix[nSuffix]; (unshared suffix of next term)
+**   }
+** }
+**
+** Here, optional { X } means an optional element, while array { X }
+** means zero or more occurrences of X, adjacent in memory.
+**
+** An interior node encodes n terms separating n+1 subtrees.  The
+** subtree blocks are contiguous, so only the first subtree's blockid
+** is encoded.  The subtree at iBlockid will contain all terms less
+** than the first term encoded (or all terms if no term is encoded).
+** Otherwise, for terms greater than or equal to pTerm[i] but less
+** than pTerm[i+1], the subtree for that term will be rooted at
+** iBlockid+i.  Interior nodes only store enough term data to
+** distinguish adjacent children (if the rightmost term of the left
+** child is "something", and the leftmost term of the right child is
+** "wicked", only "w" is stored).
+**
+** New data is spilled to a new interior node at the same height when
+** the current node exceeds INTERIOR_MAX bytes (default 2048).
+** INTERIOR_MIN_TERMS (default 7) keeps large terms from monopolizing
+** interior nodes and making the tree too skinny.  The interior nodes
+** at a given height are naturally tracked by interior nodes at
+** height+1, and so on.
+**
+**
+**** Segment directory ****
+** The segment directory in table %_segdir stores meta-information for
+** merging and deleting segments, and also the root node of the
+** segment's tree.
+**
+** The root node is the top node of the segment's tree after encoding
+** the entire segment, restricted to ROOT_MAX bytes (default 1024).
+** This could be either a leaf node or an interior node.  If the top
+** node requires more than ROOT_MAX bytes, it is flushed to %_segments
+** and a new root interior node is generated (which should always fit
+** within ROOT_MAX because it only needs space for 2 varints, the
+** height and the blockid of the previous root).
+**
+** The meta-information in the segment directory is:
+**   level               - segment level (see below)
+**   idx                 - index within level
+**                       - (level,idx uniquely identify a segment)
+**   start_block         - first leaf node
+**   leaves_end_block    - last leaf node
+**   end_block           - last block (including interior nodes)
+**   root                - contents of root node
+**
+** If the root node is a leaf node, then start_block,
+** leaves_end_block, and end_block are all 0.
+**
+**
+**** Segment merging ****
+** To amortize update costs, segments are grouped into levels and
+** merged in batches.  Each increase in level represents exponentially
+** more documents.
+**
+** New documents (actually, document updates) are tokenized and
+** written individually (using LeafWriter) to a level 0 segment, with
+** incrementing idx.  When idx reaches MERGE_COUNT (default 16), all
+** level 0 segments are merged into a single level 1 segment.  Level 1
+** is populated like level 0, and eventually MERGE_COUNT level 1
+** segments are merged to a single level 2 segment (representing
+** MERGE_COUNT^2 updates), and so on.
+**
+** A segment merge traverses all segments at a given level in
+** parallel, performing a straightforward sorted merge.  Since segment
+** leaf nodes are written in to the %_segments table in order, this
+** merge traverses the underlying sqlite disk structures efficiently.
+** After the merge, all segment blocks from the merged level are
+** deleted.
+**
+** MERGE_COUNT controls how often we merge segments.  16 seems to be
+** somewhat of a sweet spot for insertion performance.  32 and 64 show
+** very similar performance numbers to 16 on insertion, though they're
+** a tiny bit slower (perhaps due to more overhead in merge-time
+** sorting).  8 is about 20% slower than 16, 4 about 50% slower than
+** 16, 2 about 66% slower than 16.
+**
+** At query time, high MERGE_COUNT increases the number of segments
+** which need to be scanned and merged.  For instance, with 100k docs
+** inserted:
+**
+**    MERGE_COUNT   segments
+**       16           25
+**        8           12
+**        4           10
+**        2            6
+**
+** This appears to have only a moderate impact on queries for very
+** frequent terms (which are somewhat dominated by segment merge
+** costs), and infrequent and non-existent terms still seem to be fast
+** even with many segments.
+**
+** TODO(shess) That said, it would be nice to have a better query-side
+** argument for MERGE_COUNT of 16.  Also, it is possible/likely that
+** optimizations to things like doclist merging will swing the sweet
+** spot around.
+**
+**
+**
+**** Handling of deletions and updates ****
+** Since we're using a segmented structure, with no docid-oriented
+** index into the term index, we clearly cannot simply update the term
+** index when a document is deleted or updated.  For deletions, we
+** write an empty doclist (varint(docid) varint(POS_END)), for updates
+** we simply write the new doclist.  Segment merges overwrite older
+** data for a particular docid with newer data, so deletes or updates
+** will eventually overtake the earlier data and knock it out.  The
+** query logic likewise merges doclists so that newer data knocks out
+** older data.
+*/
+
+/************** Include fts3Int.h in the middle of fts3.c ********************/
+/************** Begin file fts3Int.h *****************************************/
+/*
+** 2009 Nov 12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+#ifndef _FTSINT_H
+#define _FTSINT_H
+
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+
+/* FTS3/FTS4 require virtual tables */
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+# undef SQLITE_ENABLE_FTS3
+# undef SQLITE_ENABLE_FTS4
+#endif
+
+/*
+** FTS4 is really an extension for FTS3.  It is enabled using the
+** SQLITE_ENABLE_FTS3 macro.  But to avoid confusion we also all
+** the SQLITE_ENABLE_FTS4 macro to serve as an alisse for SQLITE_ENABLE_FTS3.
+*/
+#if defined(SQLITE_ENABLE_FTS4) && !defined(SQLITE_ENABLE_FTS3)
+# define SQLITE_ENABLE_FTS3
+#endif
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* If not building as part of the core, include sqlite3ext.h. */
+#ifndef SQLITE_CORE
+/* # include "sqlite3ext.h" */
+SQLITE_EXTENSION_INIT3
+#endif
+
+/* #include "sqlite3.h" */
+/************** Include fts3_tokenizer.h in the middle of fts3Int.h **********/
+/************** Begin file fts3_tokenizer.h **********************************/
+/*
+** 2006 July 10
+**
+** The author disclaims copyright to this source code.
+**
+*************************************************************************
+** Defines the interface to tokenizers used by fulltext-search.  There
+** are three basic components:
+**
+** sqlite3_tokenizer_module is a singleton defining the tokenizer
+** interface functions.  This is essentially the class structure for
+** tokenizers.
+**
+** sqlite3_tokenizer is used to define a particular tokenizer, perhaps
+** including customization information defined at creation time.
+**
+** sqlite3_tokenizer_cursor is generated by a tokenizer to generate
+** tokens from a particular input.
+*/
+#ifndef _FTS3_TOKENIZER_H_
+#define _FTS3_TOKENIZER_H_
+
+/* TODO(shess) Only used for SQLITE_OK and SQLITE_DONE at this time.
+** If tokenizers are to be allowed to call sqlite3_*() functions, then
+** we will need a way to register the API consistently.
+*/
+/* #include "sqlite3.h" */
+
+/*
+** Structures used by the tokenizer interface. When a new tokenizer
+** implementation is registered, the caller provides a pointer to
+** an sqlite3_tokenizer_module containing pointers to the callback
+** functions that make up an implementation.
+**
+** When an fts3 table is created, it passes any arguments passed to
+** the tokenizer clause of the CREATE VIRTUAL TABLE statement to the
+** sqlite3_tokenizer_module.xCreate() function of the requested tokenizer
+** implementation. The xCreate() function in turn returns an
+** sqlite3_tokenizer structure representing the specific tokenizer to
+** be used for the fts3 table (customized by the tokenizer clause arguments).
+**
+** To tokenize an input buffer, the sqlite3_tokenizer_module.xOpen()
+** method is called. It returns an sqlite3_tokenizer_cursor object
+** that may be used to tokenize a specific input buffer based on
+** the tokenization rules supplied by a specific sqlite3_tokenizer
+** object.
+*/
+typedef struct sqlite3_tokenizer_module sqlite3_tokenizer_module;
+typedef struct sqlite3_tokenizer sqlite3_tokenizer;
+typedef struct sqlite3_tokenizer_cursor sqlite3_tokenizer_cursor;
+
+struct sqlite3_tokenizer_module {
+
+  /*
+  ** Structure version. Should always be set to 0 or 1.
+  */
+  int iVersion;
+
+  /*
+  ** Create a new tokenizer. The values in the argv[] array are the
+  ** arguments passed to the "tokenizer" clause of the CREATE VIRTUAL
+  ** TABLE statement that created the fts3 table. For example, if
+  ** the following SQL is executed:
+  **
+  **   CREATE .. USING fts3( ... , tokenizer <tokenizer-name> arg1 arg2)
+  **
+  ** then argc is set to 2, and the argv[] array contains pointers
+  ** to the strings "arg1" and "arg2".
+  **
+  ** This method should return either SQLITE_OK (0), or an SQLite error
+  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
+  ** to point at the newly created tokenizer structure. The generic
+  ** sqlite3_tokenizer.pModule variable should not be initialized by
+  ** this callback. The caller will do so.
+  */
+  int (*xCreate)(
+    int argc,                           /* Size of argv array */
+    const char *const*argv,             /* Tokenizer argument strings */
+    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
+  );
+
+  /*
+  ** Destroy an existing tokenizer. The fts3 module calls this method
+  ** exactly once for each successful call to xCreate().
+  */
+  int (*xDestroy)(sqlite3_tokenizer *pTokenizer);
+
+  /*
+  ** Create a tokenizer cursor to tokenize an input buffer. The caller
+  ** is responsible for ensuring that the input buffer remains valid
+  ** until the cursor is closed (using the xClose() method).
+  */
+  int (*xOpen)(
+    sqlite3_tokenizer *pTokenizer,       /* Tokenizer object */
+    const char *pInput, int nBytes,      /* Input buffer */
+    sqlite3_tokenizer_cursor **ppCursor  /* OUT: Created tokenizer cursor */
+  );
+
+  /*
+  ** Destroy an existing tokenizer cursor. The fts3 module calls this
+  ** method exactly once for each successful call to xOpen().
+  */
+  int (*xClose)(sqlite3_tokenizer_cursor *pCursor);
+
+  /*
+  ** Retrieve the next token from the tokenizer cursor pCursor. This
+  ** method should either return SQLITE_OK and set the values of the
+  ** "OUT" variables identified below, or SQLITE_DONE to indicate that
+  ** the end of the buffer has been reached, or an SQLite error code.
+  **
+  ** *ppToken should be set to point at a buffer containing the
+  ** normalized version of the token (i.e. after any case-folding and/or
+  ** stemming has been performed). *pnBytes should be set to the length
+  ** of this buffer in bytes. The input text that generated the token is
+  ** identified by the byte offsets returned in *piStartOffset and
+  ** *piEndOffset. *piStartOffset should be set to the index of the first
+  ** byte of the token in the input buffer. *piEndOffset should be set
+  ** to the index of the first byte just past the end of the token in
+  ** the input buffer.
+  **
+  ** The buffer *ppToken is set to point at is managed by the tokenizer
+  ** implementation. It is only required to be valid until the next call
+  ** to xNext() or xClose().
+  */
+  /* TODO(shess) current implementation requires pInput to be
+  ** nul-terminated.  This should either be fixed, or pInput/nBytes
+  ** should be converted to zInput.
+  */
+  int (*xNext)(
+    sqlite3_tokenizer_cursor *pCursor,   /* Tokenizer cursor */
+    const char **ppToken, int *pnBytes,  /* OUT: Normalized text for token */
+    int *piStartOffset,  /* OUT: Byte offset of token in input buffer */
+    int *piEndOffset,    /* OUT: Byte offset of end of token in input buffer */
+    int *piPosition      /* OUT: Number of tokens returned before this one */
+  );
+
+  /***********************************************************************
+  ** Methods below this point are only available if iVersion>=1.
+  */
+
+  /*
+  ** Configure the language id of a tokenizer cursor.
+  */
+  int (*xLanguageid)(sqlite3_tokenizer_cursor *pCsr, int iLangid);
+};
+
+struct sqlite3_tokenizer {
+  const sqlite3_tokenizer_module *pModule;  /* The module for this tokenizer */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+struct sqlite3_tokenizer_cursor {
+  sqlite3_tokenizer *pTokenizer;       /* Tokenizer for this cursor. */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+int fts3_global_term_cnt(int iTerm, int iCol);
+int fts3_term_cnt(int iTerm, int iCol);
+
+
+#endif /* _FTS3_TOKENIZER_H_ */
+
+/************** End of fts3_tokenizer.h **************************************/
+/************** Continuing where we left off in fts3Int.h ********************/
+/************** Include fts3_hash.h in the middle of fts3Int.h ***************/
+/************** Begin file fts3_hash.h ***************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for the generic hash-table implementation
+** used in SQLite.  We've modified it slightly to serve as a standalone
+** hash table implementation for the full-text indexing module.
+**
+*/
+#ifndef _FTS3_HASH_H_
+#define _FTS3_HASH_H_
+
+/* Forward declarations of structures. */
+typedef struct Fts3Hash Fts3Hash;
+typedef struct Fts3HashElem Fts3HashElem;
+
+/* A complete hash table is an instance of the following structure.
+** The internals of this structure are intended to be opaque -- client
+** code should not attempt to access or modify the fields of this structure
+** directly.  Change this structure only by using the routines below.
+** However, many of the "procedures" and "functions" for modifying and
+** accessing this structure are really macros, so we can't really make
+** this structure opaque.
+*/
+struct Fts3Hash {
+  char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
+  char copyKey;           /* True if copy of key made on insert */
+  int count;              /* Number of entries in this table */
+  Fts3HashElem *first;    /* The first element of the array */
+  int htsize;             /* Number of buckets in the hash table */
+  struct _fts3ht {        /* the hash table */
+    int count;               /* Number of entries with this hash */
+    Fts3HashElem *chain;     /* Pointer to first entry with this hash */
+  } *ht;
+};
+
+/* Each element in the hash table is an instance of the following
+** structure.  All elements are stored on a single doubly-linked list.
+**
+** Again, this structure is intended to be opaque, but it can't really
+** be opaque because it is used by macros.
+*/
+struct Fts3HashElem {
+  Fts3HashElem *next, *prev; /* Next and previous elements in the table */
+  void *data;                /* Data associated with this element */
+  void *pKey; int nKey;      /* Key associated with this element */
+};
+
+/*
+** There are 2 different modes of operation for a hash table:
+**
+**   FTS3_HASH_STRING        pKey points to a string that is nKey bytes long
+**                           (including the null-terminator, if any).  Case
+**                           is respected in comparisons.
+**
+**   FTS3_HASH_BINARY        pKey points to binary data nKey bytes long.
+**                           memcmp() is used to compare keys.
+**
+** A copy of the key is made if the copyKey parameter to fts3HashInit is 1.
+*/
+#define FTS3_HASH_STRING    1
+#define FTS3_HASH_BINARY    2
+
+/*
+** Access routines.  To delete, insert a NULL pointer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashInit(Fts3Hash *pNew, char keyClass, char copyKey);
+SQLITE_PRIVATE void *sqlite3Fts3HashInsert(Fts3Hash*, const void *pKey, int nKey, void *pData);
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const Fts3Hash*, const void *pKey, int nKey);
+SQLITE_PRIVATE void sqlite3Fts3HashClear(Fts3Hash*);
+SQLITE_PRIVATE Fts3HashElem *sqlite3Fts3HashFindElem(const Fts3Hash *, const void *, int);
+
+/*
+** Shorthand for the functions above
+*/
+#define fts3HashInit     sqlite3Fts3HashInit
+#define fts3HashInsert   sqlite3Fts3HashInsert
+#define fts3HashFind     sqlite3Fts3HashFind
+#define fts3HashClear    sqlite3Fts3HashClear
+#define fts3HashFindElem sqlite3Fts3HashFindElem
+
+/*
+** Macros for looping over all elements of a hash table.  The idiom is
+** like this:
+**
+**   Fts3Hash h;
+**   Fts3HashElem *p;
+**   ...
+**   for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){
+**     SomeStructure *pData = fts3HashData(p);
+**     // do something with pData
+**   }
+*/
+#define fts3HashFirst(H)  ((H)->first)
+#define fts3HashNext(E)   ((E)->next)
+#define fts3HashData(E)   ((E)->data)
+#define fts3HashKey(E)    ((E)->pKey)
+#define fts3HashKeysize(E) ((E)->nKey)
+
+/*
+** Number of entries in a hash table
+*/
+#define fts3HashCount(H)  ((H)->count)
+
+#endif /* _FTS3_HASH_H_ */
+
+/************** End of fts3_hash.h *******************************************/
+/************** Continuing where we left off in fts3Int.h ********************/
+
+/*
+** This constant determines the maximum depth of an FTS expression tree
+** that the library will create and use. FTS uses recursion to perform
+** various operations on the query tree, so the disadvantage of a large
+** limit is that it may allow very large queries to use large amounts
+** of stack space (perhaps causing a stack overflow).
+*/
+#ifndef SQLITE_FTS3_MAX_EXPR_DEPTH
+# define SQLITE_FTS3_MAX_EXPR_DEPTH 12
+#endif
+
+
+/*
+** This constant controls how often segments are merged. Once there are
+** FTS3_MERGE_COUNT segments of level N, they are merged into a single
+** segment of level N+1.
+*/
+#define FTS3_MERGE_COUNT 16
+
+/*
+** This is the maximum amount of data (in bytes) to store in the
+** Fts3Table.pendingTerms hash table. Normally, the hash table is
+** populated as documents are inserted/updated/deleted in a transaction
+** and used to create a new segment when the transaction is committed.
+** However if this limit is reached midway through a transaction, a new
+** segment is created and the hash table cleared immediately.
+*/
+#define FTS3_MAX_PENDING_DATA (1*1024*1024)
+
+/*
+** Macro to return the number of elements in an array. SQLite has a
+** similar macro called ArraySize(). Use a different name to avoid
+** a collision when building an amalgamation with built-in FTS3.
+*/
+#define SizeofArray(X) ((int)(sizeof(X)/sizeof(X[0])))
+
+
+#ifndef MIN
+# define MIN(x,y) ((x)<(y)?(x):(y))
+#endif
+#ifndef MAX
+# define MAX(x,y) ((x)>(y)?(x):(y))
+#endif
+
+/*
+** Maximum length of a varint encoded integer. The varint format is different
+** from that used by SQLite, so the maximum length is 10, not 9.
+*/
+#define FTS3_VARINT_MAX 10
+
+#define FTS3_BUFFER_PADDING 8
+
+/*
+** FTS4 virtual tables may maintain multiple indexes - one index of all terms
+** in the document set and zero or more prefix indexes. All indexes are stored
+** as one or more b+-trees in the %_segments and %_segdir tables.
+**
+** It is possible to determine which index a b+-tree belongs to based on the
+** value stored in the "%_segdir.level" column. Given this value L, the index
+** that the b+-tree belongs to is (L<<10). In other words, all b+-trees with
+** level values between 0 and 1023 (inclusive) belong to index 0, all levels
+** between 1024 and 2047 to index 1, and so on.
+**
+** It is considered impossible for an index to use more than 1024 levels. In
+** theory though this may happen, but only after at least
+** (FTS3_MERGE_COUNT^1024) separate flushes of the pending-terms tables.
+*/
+#define FTS3_SEGDIR_MAXLEVEL      1024
+#define FTS3_SEGDIR_MAXLEVEL_STR "1024"
+
+/*
+** The testcase() macro is only used by the amalgamation.  If undefined,
+** make it a no-op.
+*/
+#ifndef testcase
+# define testcase(X)
+#endif
+
+/*
+** Terminator values for position-lists and column-lists.
+*/
+#define POS_COLUMN  (1)     /* Column-list terminator */
+#define POS_END     (0)     /* Position-list terminator */
+
+/*
+** The assert_fts3_nc() macro is similar to the assert() macro, except that it
+** is used for assert() conditions that are true only if it can be
+** guranteed that the database is not corrupt.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_API extern int sqlite3_fts3_may_be_corrupt;
+# define assert_fts3_nc(x) assert(sqlite3_fts3_may_be_corrupt || (x))
+#else
+# define assert_fts3_nc(x) assert(x)
+#endif
+
+/*
+** This section provides definitions to allow the
+** FTS3 extension to be compiled outside of the
+** amalgamation.
+*/
+#ifndef SQLITE_AMALGAMATION
+/*
+** Macros indicating that conditional expressions are always true or
+** false.
+*/
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
+# define SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS 1
+#endif
+#if defined(SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS)
+# define ALWAYS(X)      (1)
+# define NEVER(X)       (0)
+#elif !defined(NDEBUG)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
+#else
+# define ALWAYS(X)      (X)
+# define NEVER(X)       (X)
+#endif
+
+/*
+** Internal types used by SQLite.
+*/
+typedef unsigned char u8;         /* 1-byte (or larger) unsigned integer */
+typedef short int i16;            /* 2-byte (or larger) signed integer */
+typedef unsigned int u32;         /* 4-byte unsigned integer */
+typedef sqlite3_uint64 u64;       /* 8-byte unsigned integer */
+typedef sqlite3_int64 i64;        /* 8-byte signed integer */
+
+/*
+** Macro used to suppress compiler warnings for unused parameters.
+*/
+#define UNUSED_PARAMETER(x) (void)(x)
+
+/*
+** Activate assert() only if SQLITE_TEST is enabled.
+*/
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+
+/*
+** The TESTONLY macro is used to enclose variable declarations or
+** other bits of code that are needed to support the arguments
+** within testcase() and assert() macros.
+*/
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+# define TESTONLY(X)  X
+#else
+# define TESTONLY(X)
+#endif
+
+#define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
+#define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
+
+#define deliberate_fall_through
+
+#endif /* SQLITE_AMALGAMATION */
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3Fts3Corrupt(void);
+# define FTS_CORRUPT_VTAB sqlite3Fts3Corrupt()
+#else
+# define FTS_CORRUPT_VTAB SQLITE_CORRUPT_VTAB
+#endif
+
+typedef struct Fts3Table Fts3Table;
+typedef struct Fts3Cursor Fts3Cursor;
+typedef struct Fts3Expr Fts3Expr;
+typedef struct Fts3Phrase Fts3Phrase;
+typedef struct Fts3PhraseToken Fts3PhraseToken;
+
+typedef struct Fts3Doclist Fts3Doclist;
+typedef struct Fts3SegFilter Fts3SegFilter;
+typedef struct Fts3DeferredToken Fts3DeferredToken;
+typedef struct Fts3SegReader Fts3SegReader;
+typedef struct Fts3MultiSegReader Fts3MultiSegReader;
+
+typedef struct MatchinfoBuffer MatchinfoBuffer;
+
+/*
+** A connection to a fulltext index is an instance of the following
+** structure. The xCreate and xConnect methods create an instance
+** of this structure and xDestroy and xDisconnect free that instance.
+** All other methods receive a pointer to the structure as one of their
+** arguments.
+*/
+struct Fts3Table {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  sqlite3 *db;                    /* The database connection */
+  const char *zDb;                /* logical database name */
+  const char *zName;              /* virtual table name */
+  int nColumn;                    /* number of named columns in virtual table */
+  char **azColumn;                /* column names.  malloced */
+  u8 *abNotindexed;               /* True for 'notindexed' columns */
+  sqlite3_tokenizer *pTokenizer;  /* tokenizer for inserts and queries */
+  char *zContentTbl;              /* content=xxx option, or NULL */
+  char *zLanguageid;              /* languageid=xxx option, or NULL */
+  int nAutoincrmerge;             /* Value configured by 'automerge' */
+  u32 nLeafAdd;                   /* Number of leaf blocks added this trans */
+  int bLock;                      /* Used to prevent recursive content= tbls */
+
+  /* Precompiled statements used by the implementation. Each of these
+  ** statements is run and reset within a single virtual table API call.
+  */
+  sqlite3_stmt *aStmt[40];
+  sqlite3_stmt *pSeekStmt;        /* Cache for fts3CursorSeekStmt() */
+
+  char *zReadExprlist;
+  char *zWriteExprlist;
+
+  int nNodeSize;                  /* Soft limit for node size */
+  u8 bFts4;                       /* True for FTS4, false for FTS3 */
+  u8 bHasStat;                    /* True if %_stat table exists (2==unknown) */
+  u8 bHasDocsize;                 /* True if %_docsize table exists */
+  u8 bDescIdx;                    /* True if doclists are in reverse order */
+  u8 bIgnoreSavepoint;            /* True to ignore xSavepoint invocations */
+  int nPgsz;                      /* Page size for host database */
+  char *zSegmentsTbl;             /* Name of %_segments table */
+  sqlite3_blob *pSegments;        /* Blob handle open on %_segments table */
+  int iSavepoint;
+
+  /*
+  ** The following array of hash tables is used to buffer pending index
+  ** updates during transactions. All pending updates buffered at any one
+  ** time must share a common language-id (see the FTS4 langid= feature).
+  ** The current language id is stored in variable iPrevLangid.
+  **
+  ** A single FTS4 table may have multiple full-text indexes. For each index
+  ** there is an entry in the aIndex[] array. Index 0 is an index of all the
+  ** terms that appear in the document set. Each subsequent index in aIndex[]
+  ** is an index of prefixes of a specific length.
+  **
+  ** Variable nPendingData contains an estimate the memory consumed by the
+  ** pending data structures, including hash table overhead, but not including
+  ** malloc overhead.  When nPendingData exceeds nMaxPendingData, all hash
+  ** tables are flushed to disk. Variable iPrevDocid is the docid of the most
+  ** recently inserted record.
+  */
+  int nIndex;                     /* Size of aIndex[] */
+  struct Fts3Index {
+    int nPrefix;                  /* Prefix length (0 for main terms index) */
+    Fts3Hash hPending;            /* Pending terms table for this index */
+  } *aIndex;
+  int nMaxPendingData;            /* Max pending data before flush to disk */
+  int nPendingData;               /* Current bytes of pending data */
+  sqlite_int64 iPrevDocid;        /* Docid of most recently inserted document */
+  int iPrevLangid;                /* Langid of recently inserted document */
+  int bPrevDelete;                /* True if last operation was a delete */
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+  /* State variables used for validating that the transaction control
+  ** methods of the virtual table are called at appropriate times.  These
+  ** values do not contribute to FTS functionality; they are used for
+  ** verifying the operation of the SQLite core.
+  */
+  int inTransaction;     /* True after xBegin but before xCommit/xRollback */
+  int mxSavepoint;       /* Largest valid xSavepoint integer */
+#endif
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /* True to disable the incremental doclist optimization. This is controled
+  ** by special insert command 'test-no-incr-doclist'.  */
+  int bNoIncrDoclist;
+
+  /* Number of segments in a level */
+  int nMergeCount;
+#endif
+};
+
+/* Macro to find the number of segments to merge */
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+# define MergeCount(P) ((P)->nMergeCount)
+#else
+# define MergeCount(P) FTS3_MERGE_COUNT
+#endif
+
+/*
+** When the core wants to read from the virtual table, it creates a
+** virtual table cursor (an instance of the following structure) using
+** the xOpen method. Cursors are destroyed using the xClose method.
+*/
+struct Fts3Cursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  i16 eSearch;                    /* Search strategy (see below) */
+  u8 isEof;                       /* True if at End Of Results */
+  u8 isRequireSeek;               /* True if must seek pStmt to %_content row */
+  u8 bSeekStmt;                   /* True if pStmt is a seek */
+  sqlite3_stmt *pStmt;            /* Prepared statement in use by the cursor */
+  Fts3Expr *pExpr;                /* Parsed MATCH query string */
+  int iLangid;                    /* Language being queried for */
+  int nPhrase;                    /* Number of matchable phrases in query */
+  Fts3DeferredToken *pDeferred;   /* Deferred search tokens, if any */
+  sqlite3_int64 iPrevId;          /* Previous id read from aDoclist */
+  char *pNextId;                  /* Pointer into the body of aDoclist */
+  char *aDoclist;                 /* List of docids for full-text queries */
+  int nDoclist;                   /* Size of buffer at aDoclist */
+  u8 bDesc;                       /* True to sort in descending order */
+  int eEvalmode;                  /* An FTS3_EVAL_XX constant */
+  int nRowAvg;                    /* Average size of database rows, in pages */
+  sqlite3_int64 nDoc;             /* Documents in table */
+  i64 iMinDocid;                  /* Minimum docid to return */
+  i64 iMaxDocid;                  /* Maximum docid to return */
+  int isMatchinfoNeeded;          /* True when aMatchinfo[] needs filling in */
+  MatchinfoBuffer *pMIBuffer;     /* Buffer for matchinfo data */
+};
+
+#define FTS3_EVAL_FILTER    0
+#define FTS3_EVAL_NEXT      1
+#define FTS3_EVAL_MATCHINFO 2
+
+/*
+** The Fts3Cursor.eSearch member is always set to one of the following.
+** Actualy, Fts3Cursor.eSearch can be greater than or equal to
+** FTS3_FULLTEXT_SEARCH.  If so, then Fts3Cursor.eSearch - 2 is the index
+** of the column to be searched.  For example, in
+**
+**     CREATE VIRTUAL TABLE ex1 USING fts3(a,b,c,d);
+**     SELECT docid FROM ex1 WHERE b MATCH 'one two three';
+**
+** Because the LHS of the MATCH operator is 2nd column "b",
+** Fts3Cursor.eSearch will be set to FTS3_FULLTEXT_SEARCH+1.  (+0 for a,
+** +1 for b, +2 for c, +3 for d.)  If the LHS of MATCH were "ex1"
+** indicating that all columns should be searched,
+** then eSearch would be set to FTS3_FULLTEXT_SEARCH+4.
+*/
+#define FTS3_FULLSCAN_SEARCH 0    /* Linear scan of %_content table */
+#define FTS3_DOCID_SEARCH    1    /* Lookup by rowid on %_content table */
+#define FTS3_FULLTEXT_SEARCH 2    /* Full-text index search */
+
+/*
+** The lower 16-bits of the sqlite3_index_info.idxNum value set by
+** the xBestIndex() method contains the Fts3Cursor.eSearch value described
+** above. The upper 16-bits contain a combination of the following
+** bits, used to describe extra constraints on full-text searches.
+*/
+#define FTS3_HAVE_LANGID    0x00010000      /* languageid=? */
+#define FTS3_HAVE_DOCID_GE  0x00020000      /* docid>=? */
+#define FTS3_HAVE_DOCID_LE  0x00040000      /* docid<=? */
+
+struct Fts3Doclist {
+  char *aAll;                    /* Array containing doclist (or NULL) */
+  int nAll;                      /* Size of a[] in bytes */
+  char *pNextDocid;              /* Pointer to next docid */
+
+  sqlite3_int64 iDocid;          /* Current docid (if pList!=0) */
+  int bFreeList;                 /* True if pList should be sqlite3_free()d */
+  char *pList;                   /* Pointer to position list following iDocid */
+  int nList;                     /* Length of position list */
+};
+
+/*
+** A "phrase" is a sequence of one or more tokens that must match in
+** sequence.  A single token is the base case and the most common case.
+** For a sequence of tokens contained in double-quotes (i.e. "one two three")
+** nToken will be the number of tokens in the string.
+*/
+struct Fts3PhraseToken {
+  char *z;                        /* Text of the token */
+  int n;                          /* Number of bytes in buffer z */
+  int isPrefix;                   /* True if token ends with a "*" character */
+  int bFirst;                     /* True if token must appear at position 0 */
+
+  /* Variables above this point are populated when the expression is
+  ** parsed (by code in fts3_expr.c). Below this point the variables are
+  ** used when evaluating the expression. */
+  Fts3DeferredToken *pDeferred;   /* Deferred token object for this token */
+  Fts3MultiSegReader *pSegcsr;    /* Segment-reader for this token */
+};
+
+struct Fts3Phrase {
+  /* Cache of doclist for this phrase. */
+  Fts3Doclist doclist;
+  int bIncr;                 /* True if doclist is loaded incrementally */
+  int iDoclistToken;
+
+  /* Used by sqlite3Fts3EvalPhrasePoslist() if this is a descendent of an
+  ** OR condition.  */
+  char *pOrPoslist;
+  i64 iOrDocid;
+
+  /* Variables below this point are populated by fts3_expr.c when parsing
+  ** a MATCH expression. Everything above is part of the evaluation phase.
+  */
+  int nToken;                /* Number of tokens in the phrase */
+  int iColumn;               /* Index of column this phrase must match */
+  Fts3PhraseToken aToken[1]; /* One entry for each token in the phrase */
+};
+
+/*
+** A tree of these objects forms the RHS of a MATCH operator.
+**
+** If Fts3Expr.eType is FTSQUERY_PHRASE and isLoaded is true, then aDoclist
+** points to a malloced buffer, size nDoclist bytes, containing the results
+** of this phrase query in FTS3 doclist format. As usual, the initial
+** "Length" field found in doclists stored on disk is omitted from this
+** buffer.
+**
+** Variable aMI is used only for FTSQUERY_NEAR nodes to store the global
+** matchinfo data. If it is not NULL, it points to an array of size nCol*3,
+** where nCol is the number of columns in the queried FTS table. The array
+** is populated as follows:
+**
+**   aMI[iCol*3 + 0] = Undefined
+**   aMI[iCol*3 + 1] = Number of occurrences
+**   aMI[iCol*3 + 2] = Number of rows containing at least one instance
+**
+** The aMI array is allocated using sqlite3_malloc(). It should be freed
+** when the expression node is.
+*/
+struct Fts3Expr {
+  int eType;                 /* One of the FTSQUERY_XXX values defined below */
+  int nNear;                 /* Valid if eType==FTSQUERY_NEAR */
+  Fts3Expr *pParent;         /* pParent->pLeft==this or pParent->pRight==this */
+  Fts3Expr *pLeft;           /* Left operand */
+  Fts3Expr *pRight;          /* Right operand */
+  Fts3Phrase *pPhrase;       /* Valid if eType==FTSQUERY_PHRASE */
+
+  /* The following are used by the fts3_eval.c module. */
+  sqlite3_int64 iDocid;      /* Current docid */
+  u8 bEof;                   /* True this expression is at EOF already */
+  u8 bStart;                 /* True if iDocid is valid */
+  u8 bDeferred;              /* True if this expression is entirely deferred */
+
+  /* The following are used by the fts3_snippet.c module. */
+  int iPhrase;               /* Index of this phrase in matchinfo() results */
+  u32 *aMI;                  /* See above */
+};
+
+/*
+** Candidate values for Fts3Query.eType. Note that the order of the first
+** four values is in order of precedence when parsing expressions. For
+** example, the following:
+**
+**   "a OR b AND c NOT d NEAR e"
+**
+** is equivalent to:
+**
+**   "a OR (b AND (c NOT (d NEAR e)))"
+*/
+#define FTSQUERY_NEAR   1
+#define FTSQUERY_NOT    2
+#define FTSQUERY_AND    3
+#define FTSQUERY_OR     4
+#define FTSQUERY_PHRASE 5
+
+
+/* fts3_write.c */
+SQLITE_PRIVATE int sqlite3Fts3UpdateMethod(sqlite3_vtab*,int,sqlite3_value**,sqlite3_int64*);
+SQLITE_PRIVATE int sqlite3Fts3PendingTermsFlush(Fts3Table *);
+SQLITE_PRIVATE void sqlite3Fts3PendingTermsClear(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3Optimize(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3SegReaderNew(int, int, sqlite3_int64,
+  sqlite3_int64, sqlite3_int64, const char *, int, Fts3SegReader**);
+SQLITE_PRIVATE int sqlite3Fts3SegReaderPending(
+  Fts3Table*,int,const char*,int,int,Fts3SegReader**);
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFree(Fts3SegReader *);
+SQLITE_PRIVATE int sqlite3Fts3AllSegdirs(Fts3Table*, int, int, int, sqlite3_stmt **);
+SQLITE_PRIVATE int sqlite3Fts3ReadBlock(Fts3Table*, sqlite3_int64, char **, int*, int*);
+
+SQLITE_PRIVATE int sqlite3Fts3SelectDoctotal(Fts3Table *, sqlite3_stmt **);
+SQLITE_PRIVATE int sqlite3Fts3SelectDocsize(Fts3Table *, sqlite3_int64, sqlite3_stmt **);
+
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *);
+SQLITE_PRIVATE int sqlite3Fts3DeferToken(Fts3Cursor *, Fts3PhraseToken *, int);
+SQLITE_PRIVATE int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *);
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *);
+SQLITE_PRIVATE int sqlite3Fts3DeferredTokenList(Fts3DeferredToken *, char **, int *);
+#else
+# define sqlite3Fts3FreeDeferredTokens(x)
+# define sqlite3Fts3DeferToken(x,y,z) SQLITE_OK
+# define sqlite3Fts3CacheDeferredDoclists(x) SQLITE_OK
+# define sqlite3Fts3FreeDeferredDoclists(x)
+# define sqlite3Fts3DeferredTokenList(x,y,z) SQLITE_OK
+#endif
+
+SQLITE_PRIVATE void sqlite3Fts3SegmentsClose(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3MaxLevel(Fts3Table *, int *);
+
+/* Special values interpreted by sqlite3SegReaderCursor() */
+#define FTS3_SEGCURSOR_PENDING        -1
+#define FTS3_SEGCURSOR_ALL            -2
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStart(Fts3Table*, Fts3MultiSegReader*, Fts3SegFilter*);
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStep(Fts3Table *, Fts3MultiSegReader *);
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFinish(Fts3MultiSegReader *);
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderCursor(Fts3Table *,
+    int, int, int, const char *, int, int, int, Fts3MultiSegReader *);
+
+/* Flags allowed as part of the 4th argument to SegmentReaderIterate() */
+#define FTS3_SEGMENT_REQUIRE_POS   0x00000001
+#define FTS3_SEGMENT_IGNORE_EMPTY  0x00000002
+#define FTS3_SEGMENT_COLUMN_FILTER 0x00000004
+#define FTS3_SEGMENT_PREFIX        0x00000008
+#define FTS3_SEGMENT_SCAN          0x00000010
+#define FTS3_SEGMENT_FIRST         0x00000020
+
+/* Type passed as 4th argument to SegmentReaderIterate() */
+struct Fts3SegFilter {
+  const char *zTerm;
+  int nTerm;
+  int iCol;
+  int flags;
+};
+
+struct Fts3MultiSegReader {
+  /* Used internally by sqlite3Fts3SegReaderXXX() calls */
+  Fts3SegReader **apSegment;      /* Array of Fts3SegReader objects */
+  int nSegment;                   /* Size of apSegment array */
+  int nAdvance;                   /* How many seg-readers to advance */
+  Fts3SegFilter *pFilter;         /* Pointer to filter object */
+  char *aBuffer;                  /* Buffer to merge doclists in */
+  i64 nBuffer;                    /* Allocated size of aBuffer[] in bytes */
+
+  int iColFilter;                 /* If >=0, filter for this column */
+  int bRestart;
+
+  /* Used by fts3.c only. */
+  int nCost;                      /* Cost of running iterator */
+  int bLookup;                    /* True if a lookup of a single entry. */
+
+  /* Output values. Valid only after Fts3SegReaderStep() returns SQLITE_ROW. */
+  char *zTerm;                    /* Pointer to term buffer */
+  int nTerm;                      /* Size of zTerm in bytes */
+  char *aDoclist;                 /* Pointer to doclist buffer */
+  int nDoclist;                   /* Size of aDoclist[] in bytes */
+};
+
+SQLITE_PRIVATE int sqlite3Fts3Incrmerge(Fts3Table*,int,int);
+
+#define fts3GetVarint32(p, piVal) (                                           \
+  (*(u8*)(p)&0x80) ? sqlite3Fts3GetVarint32(p, piVal) : (*piVal=*(u8*)(p), 1) \
+)
+
+/* fts3.c */
+SQLITE_PRIVATE void sqlite3Fts3ErrMsg(char**,const char*,...);
+SQLITE_PRIVATE int sqlite3Fts3PutVarint(char *, sqlite3_int64);
+SQLITE_PRIVATE int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
+SQLITE_PRIVATE int sqlite3Fts3GetVarintU(const char *, sqlite_uint64 *);
+SQLITE_PRIVATE int sqlite3Fts3GetVarintBounded(const char*,const char*,sqlite3_int64*);
+SQLITE_PRIVATE int sqlite3Fts3GetVarint32(const char *, int *);
+SQLITE_PRIVATE int sqlite3Fts3VarintLen(sqlite3_uint64);
+SQLITE_PRIVATE void sqlite3Fts3Dequote(char *);
+SQLITE_PRIVATE void sqlite3Fts3DoclistPrev(int,char*,int,char**,sqlite3_int64*,int*,u8*);
+SQLITE_PRIVATE int sqlite3Fts3EvalPhraseStats(Fts3Cursor *, Fts3Expr *, u32 *);
+SQLITE_PRIVATE int sqlite3Fts3FirstFilter(sqlite3_int64, char *, int, char *);
+SQLITE_PRIVATE void sqlite3Fts3CreateStatTable(int*, Fts3Table*);
+SQLITE_PRIVATE int sqlite3Fts3EvalTestDeferred(Fts3Cursor *pCsr, int *pRc);
+SQLITE_PRIVATE int sqlite3Fts3ReadInt(const char *z, int *pnOut);
+
+/* fts3_tokenizer.c */
+SQLITE_PRIVATE const char *sqlite3Fts3NextToken(const char *, int *);
+SQLITE_PRIVATE int sqlite3Fts3InitHashTable(sqlite3 *, Fts3Hash *, const char *);
+SQLITE_PRIVATE int sqlite3Fts3InitTokenizer(Fts3Hash *pHash, const char *,
+    sqlite3_tokenizer **, char **
+);
+SQLITE_PRIVATE int sqlite3Fts3IsIdChar(char);
+
+/* fts3_snippet.c */
+SQLITE_PRIVATE void sqlite3Fts3Offsets(sqlite3_context*, Fts3Cursor*);
+SQLITE_PRIVATE void sqlite3Fts3Snippet(sqlite3_context *, Fts3Cursor *, const char *,
+  const char *, const char *, int, int
+);
+SQLITE_PRIVATE void sqlite3Fts3Matchinfo(sqlite3_context *, Fts3Cursor *, const char *);
+SQLITE_PRIVATE void sqlite3Fts3MIBufferFree(MatchinfoBuffer *p);
+
+/* fts3_expr.c */
+SQLITE_PRIVATE int sqlite3Fts3ExprParse(sqlite3_tokenizer *, int,
+  char **, int, int, int, const char *, int, Fts3Expr **, char **
+);
+SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *);
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE int sqlite3Fts3ExprInitTestInterface(sqlite3 *db, Fts3Hash*);
+SQLITE_PRIVATE int sqlite3Fts3InitTerm(sqlite3 *db);
+#endif
+SQLITE_PRIVATE void *sqlite3Fts3MallocZero(i64 nByte);
+
+SQLITE_PRIVATE int sqlite3Fts3OpenTokenizer(sqlite3_tokenizer *, int, const char *, int,
+  sqlite3_tokenizer_cursor **
+);
+
+/* fts3_aux.c */
+SQLITE_PRIVATE int sqlite3Fts3InitAux(sqlite3 *db);
+
+SQLITE_PRIVATE void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *);
+
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrStart(
+    Fts3Table*, Fts3MultiSegReader*, int, const char*, int);
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrNext(
+    Fts3Table *, Fts3MultiSegReader *, sqlite3_int64 *, char **, int *);
+SQLITE_PRIVATE int sqlite3Fts3EvalPhrasePoslist(Fts3Cursor *, Fts3Expr *, int iCol, char **);
+SQLITE_PRIVATE int sqlite3Fts3MsrOvfl(Fts3Cursor *, Fts3MultiSegReader *, int *);
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr);
+SQLITE_PRIVATE int sqlite3Fts3MsrCancel(Fts3Cursor*, Fts3Expr*);
+
+/* fts3_tokenize_vtab.c */
+SQLITE_PRIVATE int sqlite3Fts3InitTok(sqlite3*, Fts3Hash *, void(*xDestroy)(void*));
+
+/* fts3_unicode2.c (functions generated by parsing unicode text files) */
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+SQLITE_PRIVATE int sqlite3FtsUnicodeFold(int, int);
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsalnum(int);
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsdiacritic(int);
+#endif
+
+SQLITE_PRIVATE int sqlite3Fts3ExprIterate(Fts3Expr*, int (*x)(Fts3Expr*,int,void*), void*);
+
+SQLITE_PRIVATE int sqlite3Fts3IntegrityCheck(Fts3Table *p, int *pbOk);
+
+#endif /* !SQLITE_CORE || SQLITE_ENABLE_FTS3 */
+#endif /* _FTSINT_H */
+
+/************** End of fts3Int.h *********************************************/
+/************** Continuing where we left off in fts3.c ***********************/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+#if defined(SQLITE_ENABLE_FTS3) && !defined(SQLITE_CORE)
+# define SQLITE_CORE 1
+#endif
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stddef.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+/* #include <stdarg.h> */
+
+/* #include "fts3.h" */
+#ifndef SQLITE_CORE
+/* # include "sqlite3ext.h" */
+  SQLITE_EXTENSION_INIT1
+#endif
+
+typedef struct Fts3HashWrapper Fts3HashWrapper;
+struct Fts3HashWrapper {
+  Fts3Hash hash;                  /* Hash table */
+  int nRef;                       /* Number of pointers to this object */
+};
+
+static int fts3EvalNext(Fts3Cursor *pCsr);
+static int fts3EvalStart(Fts3Cursor *pCsr);
+static int fts3TermSegReaderCursor(
+    Fts3Cursor *, const char *, int, int, Fts3MultiSegReader **);
+
+/*
+** This variable is set to false when running tests for which the on disk
+** structures should not be corrupt. Otherwise, true. If it is false, extra
+** assert() conditions in the fts3 code are activated - conditions that are
+** only true if it is guaranteed that the fts3 database is not corrupt.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_API int sqlite3_fts3_may_be_corrupt = 1;
+#endif
+
+/*
+** Write a 64-bit variable-length integer to memory starting at p[0].
+** The length of data written will be between 1 and FTS3_VARINT_MAX bytes.
+** The number of bytes written is returned.
+*/
+SQLITE_PRIVATE int sqlite3Fts3PutVarint(char *p, sqlite_int64 v){
+  unsigned char *q = (unsigned char *) p;
+  sqlite_uint64 vu = v;
+  do{
+    *q++ = (unsigned char) ((vu & 0x7f) | 0x80);
+    vu >>= 7;
+  }while( vu!=0 );
+  q[-1] &= 0x7f;  /* turn off high bit in final byte */
+  assert( q - (unsigned char *)p <= FTS3_VARINT_MAX );
+  return (int) (q - (unsigned char *)p);
+}
+
+#define GETVARINT_STEP(v, ptr, shift, mask1, mask2, var, ret) \
+  v = (v & mask1) | ( (*(const unsigned char*)(ptr++)) << shift );  \
+  if( (v & mask2)==0 ){ var = v; return ret; }
+#define GETVARINT_INIT(v, ptr, shift, mask1, mask2, var, ret) \
+  v = (*ptr++);                                               \
+  if( (v & mask2)==0 ){ var = v; return ret; }
+
+SQLITE_PRIVATE int sqlite3Fts3GetVarintU(const char *pBuf, sqlite_uint64 *v){
+  const unsigned char *p = (const unsigned char*)pBuf;
+  const unsigned char *pStart = p;
+  u32 a;
+  u64 b;
+  int shift;
+
+  GETVARINT_INIT(a, p, 0,  0x00,     0x80, *v, 1);
+  GETVARINT_STEP(a, p, 7,  0x7F,     0x4000, *v, 2);
+  GETVARINT_STEP(a, p, 14, 0x3FFF,   0x200000, *v, 3);
+  GETVARINT_STEP(a, p, 21, 0x1FFFFF, 0x10000000, *v, 4);
+  b = (a & 0x0FFFFFFF );
+
+  for(shift=28; shift<=63; shift+=7){
+    u64 c = *p++;
+    b += (c&0x7F) << shift;
+    if( (c & 0x80)==0 ) break;
+  }
+  *v = b;
+  return (int)(p - pStart);
+}
+
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read, or 0 on error.
+** The value is stored in *v.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarint(const char *pBuf, sqlite_int64 *v){
+  return sqlite3Fts3GetVarintU(pBuf, (sqlite3_uint64*)v);
+}
+
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0] and
+** not extending past pEnd[-1].
+** Return the number of bytes read, or 0 on error.
+** The value is stored in *v.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarintBounded(
+  const char *pBuf,
+  const char *pEnd,
+  sqlite_int64 *v
+){
+  const unsigned char *p = (const unsigned char*)pBuf;
+  const unsigned char *pStart = p;
+  const unsigned char *pX = (const unsigned char*)pEnd;
+  u64 b = 0;
+  int shift;
+  for(shift=0; shift<=63; shift+=7){
+    u64 c = p<pX ? *p : 0;
+    p++;
+    b += (c&0x7F) << shift;
+    if( (c & 0x80)==0 ) break;
+  }
+  *v = b;
+  return (int)(p - pStart);
+}
+
+/*
+** Similar to sqlite3Fts3GetVarint(), except that the output is truncated to
+** a non-negative 32-bit integer before it is returned.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarint32(const char *p, int *pi){
+  const unsigned char *ptr = (const unsigned char*)p;
+  u32 a;
+
+#ifndef fts3GetVarint32
+  GETVARINT_INIT(a, ptr, 0,  0x00,     0x80, *pi, 1);
+#else
+  a = (*ptr++);
+  assert( a & 0x80 );
+#endif
+
+  GETVARINT_STEP(a, ptr, 7,  0x7F,     0x4000, *pi, 2);
+  GETVARINT_STEP(a, ptr, 14, 0x3FFF,   0x200000, *pi, 3);
+  GETVARINT_STEP(a, ptr, 21, 0x1FFFFF, 0x10000000, *pi, 4);
+  a = (a & 0x0FFFFFFF );
+  *pi = (int)(a | ((u32)(*ptr & 0x07) << 28));
+  assert( 0==(a & 0x80000000) );
+  assert( *pi>=0 );
+  return 5;
+}
+
+/*
+** Return the number of bytes required to encode v as a varint
+*/
+SQLITE_PRIVATE int sqlite3Fts3VarintLen(sqlite3_uint64 v){
+  int i = 0;
+  do{
+    i++;
+    v >>= 7;
+  }while( v!=0 );
+  return i;
+}
+
+/*
+** Convert an SQL-style quoted string into a normal string by removing
+** the quote characters.  The conversion is done in-place.  If the
+** input does not begin with a quote character, then this routine
+** is a no-op.
+**
+** Examples:
+**
+**     "abc"   becomes   abc
+**     'xyz'   becomes   xyz
+**     [pqr]   becomes   pqr
+**     `mno`   becomes   mno
+**
+*/
+SQLITE_PRIVATE void sqlite3Fts3Dequote(char *z){
+  char quote;                     /* Quote character (if any ) */
+
+  quote = z[0];
+  if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){
+    int iIn = 1;                  /* Index of next byte to read from input */
+    int iOut = 0;                 /* Index of next byte to write to output */
+
+    /* If the first byte was a '[', then the close-quote character is a ']' */
+    if( quote=='[' ) quote = ']';
+
+    while( z[iIn] ){
+      if( z[iIn]==quote ){
+        if( z[iIn+1]!=quote ) break;
+        z[iOut++] = quote;
+        iIn += 2;
+      }else{
+        z[iOut++] = z[iIn++];
+      }
+    }
+    z[iOut] = '\0';
+  }
+}
+
+/*
+** Read a single varint from the doclist at *pp and advance *pp to point
+** to the first byte past the end of the varint.  Add the value of the varint
+** to *pVal.
+*/
+static void fts3GetDeltaVarint(char **pp, sqlite3_int64 *pVal){
+  sqlite3_int64 iVal;
+  *pp += sqlite3Fts3GetVarint(*pp, &iVal);
+  *pVal += iVal;
+}
+
+/*
+** When this function is called, *pp points to the first byte following a
+** varint that is part of a doclist (or position-list, or any other list
+** of varints). This function moves *pp to point to the start of that varint,
+** and sets *pVal by the varint value.
+**
+** Argument pStart points to the first byte of the doclist that the
+** varint is part of.
+*/
+static void fts3GetReverseVarint(
+  char **pp,
+  char *pStart,
+  sqlite3_int64 *pVal
+){
+  sqlite3_int64 iVal;
+  char *p;
+
+  /* Pointer p now points at the first byte past the varint we are
+  ** interested in. So, unless the doclist is corrupt, the 0x80 bit is
+  ** clear on character p[-1]. */
+  for(p = (*pp)-2; p>=pStart && *p&0x80; p--);
+  p++;
+  *pp = p;
+
+  sqlite3Fts3GetVarint(p, &iVal);
+  *pVal = iVal;
+}
+
+/*
+** The xDisconnect() virtual table method.
+*/
+static int fts3DisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int i;
+
+  assert( p->nPendingData==0 );
+  assert( p->pSegments==0 );
+
+  /* Free any prepared statements held */
+  sqlite3_finalize(p->pSeekStmt);
+  for(i=0; i<SizeofArray(p->aStmt); i++){
+    sqlite3_finalize(p->aStmt[i]);
+  }
+  sqlite3_free(p->zSegmentsTbl);
+  sqlite3_free(p->zReadExprlist);
+  sqlite3_free(p->zWriteExprlist);
+  sqlite3_free(p->zContentTbl);
+  sqlite3_free(p->zLanguageid);
+
+  /* Invoke the tokenizer destructor to free the tokenizer. */
+  p->pTokenizer->pModule->xDestroy(p->pTokenizer);
+
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Write an error message into *pzErr
+*/
+SQLITE_PRIVATE void sqlite3Fts3ErrMsg(char **pzErr, const char *zFormat, ...){
+  va_list ap;
+  sqlite3_free(*pzErr);
+  va_start(ap, zFormat);
+  *pzErr = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+}
+
+/*
+** Construct one or more SQL statements from the format string given
+** and then evaluate those statements. The success code is written
+** into *pRc.
+**
+** If *pRc is initially non-zero then this routine is a no-op.
+*/
+static void fts3DbExec(
+  int *pRc,              /* Success code */
+  sqlite3 *db,           /* Database in which to run SQL */
+  const char *zFormat,   /* Format string for SQL */
+  ...                    /* Arguments to the format string */
+){
+  va_list ap;
+  char *zSql;
+  if( *pRc ) return;
+  va_start(ap, zFormat);
+  zSql = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+  if( zSql==0 ){
+    *pRc = SQLITE_NOMEM;
+  }else{
+    *pRc = sqlite3_exec(db, zSql, 0, 0, 0);
+    sqlite3_free(zSql);
+  }
+}
+
+/*
+** The xDestroy() virtual table method.
+*/
+static int fts3DestroyMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int rc = SQLITE_OK;              /* Return code */
+  const char *zDb = p->zDb;        /* Name of database (e.g. "main", "temp") */
+  sqlite3 *db = p->db;             /* Database handle */
+
+  /* Drop the shadow tables */
+  fts3DbExec(&rc, db,
+    "DROP TABLE IF EXISTS %Q.'%q_segments';"
+    "DROP TABLE IF EXISTS %Q.'%q_segdir';"
+    "DROP TABLE IF EXISTS %Q.'%q_docsize';"
+    "DROP TABLE IF EXISTS %Q.'%q_stat';"
+    "%s DROP TABLE IF EXISTS %Q.'%q_content';",
+    zDb, p->zName,
+    zDb, p->zName,
+    zDb, p->zName,
+    zDb, p->zName,
+    (p->zContentTbl ? "--" : ""), zDb,p->zName
+  );
+
+  /* If everything has worked, invoke fts3DisconnectMethod() to free the
+  ** memory associated with the Fts3Table structure and return SQLITE_OK.
+  ** Otherwise, return an SQLite error code.
+  */
+  return (rc==SQLITE_OK ? fts3DisconnectMethod(pVtab) : rc);
+}
+
+
+/*
+** Invoke sqlite3_declare_vtab() to declare the schema for the FTS3 table
+** passed as the first argument. This is done as part of the xConnect()
+** and xCreate() methods.
+**
+** If *pRc is non-zero when this function is called, it is a no-op.
+** Otherwise, if an error occurs, an SQLite error code is stored in *pRc
+** before returning.
+*/
+static void fts3DeclareVtab(int *pRc, Fts3Table *p){
+  if( *pRc==SQLITE_OK ){
+    int i;                        /* Iterator variable */
+    int rc;                       /* Return code */
+    char *zSql;                   /* SQL statement passed to declare_vtab() */
+    char *zCols;                  /* List of user defined columns */
+    const char *zLanguageid;
+
+    zLanguageid = (p->zLanguageid ? p->zLanguageid : "__langid");
+    sqlite3_vtab_config(p->db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1);
+    sqlite3_vtab_config(p->db, SQLITE_VTAB_INNOCUOUS);
+
+    /* Create a list of user columns for the virtual table */
+    zCols = sqlite3_mprintf("%Q, ", p->azColumn[0]);
+    for(i=1; zCols && i<p->nColumn; i++){
+      zCols = sqlite3_mprintf("%z%Q, ", zCols, p->azColumn[i]);
+    }
+
+    /* Create the whole "CREATE TABLE" statement to pass to SQLite */
+    zSql = sqlite3_mprintf(
+        "CREATE TABLE x(%s %Q HIDDEN, docid HIDDEN, %Q HIDDEN)",
+        zCols, p->zName, zLanguageid
+    );
+    if( !zCols || !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_declare_vtab(p->db, zSql);
+    }
+
+    sqlite3_free(zSql);
+    sqlite3_free(zCols);
+    *pRc = rc;
+  }
+}
+
+/*
+** Create the %_stat table if it does not already exist.
+*/
+SQLITE_PRIVATE void sqlite3Fts3CreateStatTable(int *pRc, Fts3Table *p){
+  fts3DbExec(pRc, p->db,
+      "CREATE TABLE IF NOT EXISTS %Q.'%q_stat'"
+          "(id INTEGER PRIMARY KEY, value BLOB);",
+      p->zDb, p->zName
+  );
+  if( (*pRc)==SQLITE_OK ) p->bHasStat = 1;
+}
+
+/*
+** Create the backing store tables (%_content, %_segments and %_segdir)
+** required by the FTS3 table passed as the only argument. This is done
+** as part of the vtab xCreate() method.
+**
+** If the p->bHasDocsize boolean is true (indicating that this is an
+** FTS4 table, not an FTS3 table) then also create the %_docsize and
+** %_stat tables required by FTS4.
+*/
+static int fts3CreateTables(Fts3Table *p){
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Iterator variable */
+  sqlite3 *db = p->db;            /* The database connection */
+
+  if( p->zContentTbl==0 ){
+    const char *zLanguageid = p->zLanguageid;
+    char *zContentCols;           /* Columns of %_content table */
+
+    /* Create a list of user columns for the content table */
+    zContentCols = sqlite3_mprintf("docid INTEGER PRIMARY KEY");
+    for(i=0; zContentCols && i<p->nColumn; i++){
+      char *z = p->azColumn[i];
+      zContentCols = sqlite3_mprintf("%z, 'c%d%q'", zContentCols, i, z);
+    }
+    if( zLanguageid && zContentCols ){
+      zContentCols = sqlite3_mprintf("%z, langid", zContentCols, zLanguageid);
+    }
+    if( zContentCols==0 ) rc = SQLITE_NOMEM;
+
+    /* Create the content table */
+    fts3DbExec(&rc, db,
+       "CREATE TABLE %Q.'%q_content'(%s)",
+       p->zDb, p->zName, zContentCols
+    );
+    sqlite3_free(zContentCols);
+  }
+
+  /* Create other tables */
+  fts3DbExec(&rc, db,
+      "CREATE TABLE %Q.'%q_segments'(blockid INTEGER PRIMARY KEY, block BLOB);",
+      p->zDb, p->zName
+  );
+  fts3DbExec(&rc, db,
+      "CREATE TABLE %Q.'%q_segdir'("
+        "level INTEGER,"
+        "idx INTEGER,"
+        "start_block INTEGER,"
+        "leaves_end_block INTEGER,"
+        "end_block INTEGER,"
+        "root BLOB,"
+        "PRIMARY KEY(level, idx)"
+      ");",
+      p->zDb, p->zName
+  );
+  if( p->bHasDocsize ){
+    fts3DbExec(&rc, db,
+        "CREATE TABLE %Q.'%q_docsize'(docid INTEGER PRIMARY KEY, size BLOB);",
+        p->zDb, p->zName
+    );
+  }
+  assert( p->bHasStat==p->bFts4 );
+  if( p->bHasStat ){
+    sqlite3Fts3CreateStatTable(&rc, p);
+  }
+  return rc;
+}
+
+/*
+** Store the current database page-size in bytes in p->nPgsz.
+**
+** If *pRc is non-zero when this function is called, it is a no-op.
+** Otherwise, if an error occurs, an SQLite error code is stored in *pRc
+** before returning.
+*/
+static void fts3DatabasePageSize(int *pRc, Fts3Table *p){
+  if( *pRc==SQLITE_OK ){
+    int rc;                       /* Return code */
+    char *zSql;                   /* SQL text "PRAGMA %Q.page_size" */
+    sqlite3_stmt *pStmt;          /* Compiled "PRAGMA %Q.page_size" statement */
+
+    zSql = sqlite3_mprintf("PRAGMA %Q.page_size", p->zDb);
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare(p->db, zSql, -1, &pStmt, 0);
+      if( rc==SQLITE_OK ){
+        sqlite3_step(pStmt);
+        p->nPgsz = sqlite3_column_int(pStmt, 0);
+        rc = sqlite3_finalize(pStmt);
+      }else if( rc==SQLITE_AUTH ){
+        p->nPgsz = 1024;
+        rc = SQLITE_OK;
+      }
+    }
+    assert( p->nPgsz>0 || rc!=SQLITE_OK );
+    sqlite3_free(zSql);
+    *pRc = rc;
+  }
+}
+
+/*
+** "Special" FTS4 arguments are column specifications of the following form:
+**
+**   <key> = <value>
+**
+** There may not be whitespace surrounding the "=" character. The <value>
+** term may be quoted, but the <key> may not.
+*/
+static int fts3IsSpecialColumn(
+  const char *z,
+  int *pnKey,
+  char **pzValue
+){
+  char *zValue;
+  const char *zCsr = z;
+
+  while( *zCsr!='=' ){
+    if( *zCsr=='\0' ) return 0;
+    zCsr++;
+  }
+
+  *pnKey = (int)(zCsr-z);
+  zValue = sqlite3_mprintf("%s", &zCsr[1]);
+  if( zValue ){
+    sqlite3Fts3Dequote(zValue);
+  }
+  *pzValue = zValue;
+  return 1;
+}
+
+/*
+** Append the output of a printf() style formatting to an existing string.
+*/
+static void fts3Appendf(
+  int *pRc,                       /* IN/OUT: Error code */
+  char **pz,                      /* IN/OUT: Pointer to string buffer */
+  const char *zFormat,            /* Printf format string to append */
+  ...                             /* Arguments for printf format string */
+){
+  if( *pRc==SQLITE_OK ){
+    va_list ap;
+    char *z;
+    va_start(ap, zFormat);
+    z = sqlite3_vmprintf(zFormat, ap);
+    va_end(ap);
+    if( z && *pz ){
+      char *z2 = sqlite3_mprintf("%s%s", *pz, z);
+      sqlite3_free(z);
+      z = z2;
+    }
+    if( z==0 ) *pRc = SQLITE_NOMEM;
+    sqlite3_free(*pz);
+    *pz = z;
+  }
+}
+
+/*
+** Return a copy of input string zInput enclosed in double-quotes (") and
+** with all double quote characters escaped. For example:
+**
+**     fts3QuoteId("un \"zip\"")   ->    "un \"\"zip\"\""
+**
+** The pointer returned points to memory obtained from sqlite3_malloc(). It
+** is the callers responsibility to call sqlite3_free() to release this
+** memory.
+*/
+static char *fts3QuoteId(char const *zInput){
+  sqlite3_int64 nRet;
+  char *zRet;
+  nRet = 2 + (int)strlen(zInput)*2 + 1;
+  zRet = sqlite3_malloc64(nRet);
+  if( zRet ){
+    int i;
+    char *z = zRet;
+    *(z++) = '"';
+    for(i=0; zInput[i]; i++){
+      if( zInput[i]=='"' ) *(z++) = '"';
+      *(z++) = zInput[i];
+    }
+    *(z++) = '"';
+    *(z++) = '\0';
+  }
+  return zRet;
+}
+
+/*
+** Return a list of comma separated SQL expressions and a FROM clause that
+** could be used in a SELECT statement such as the following:
+**
+**     SELECT <list of expressions> FROM %_content AS x ...
+**
+** to return the docid, followed by each column of text data in order
+** from left to write. If parameter zFunc is not NULL, then instead of
+** being returned directly each column of text data is passed to an SQL
+** function named zFunc first. For example, if zFunc is "unzip" and the
+** table has the three user-defined columns "a", "b", and "c", the following
+** string is returned:
+**
+**     "docid, unzip(x.'a'), unzip(x.'b'), unzip(x.'c') FROM %_content AS x"
+**
+** The pointer returned points to a buffer allocated by sqlite3_malloc(). It
+** is the responsibility of the caller to eventually free it.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
+** a NULL pointer is returned). Otherwise, if an OOM error is encountered
+** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
+** no error occurs, *pRc is left unmodified.
+*/
+static char *fts3ReadExprList(Fts3Table *p, const char *zFunc, int *pRc){
+  char *zRet = 0;
+  char *zFree = 0;
+  char *zFunction;
+  int i;
+
+  if( p->zContentTbl==0 ){
+    if( !zFunc ){
+      zFunction = "";
+    }else{
+      zFree = zFunction = fts3QuoteId(zFunc);
+    }
+    fts3Appendf(pRc, &zRet, "docid");
+    for(i=0; i<p->nColumn; i++){
+      fts3Appendf(pRc, &zRet, ",%s(x.'c%d%q')", zFunction, i, p->azColumn[i]);
+    }
+    if( p->zLanguageid ){
+      fts3Appendf(pRc, &zRet, ", x.%Q", "langid");
+    }
+    sqlite3_free(zFree);
+  }else{
+    fts3Appendf(pRc, &zRet, "rowid");
+    for(i=0; i<p->nColumn; i++){
+      fts3Appendf(pRc, &zRet, ", x.'%q'", p->azColumn[i]);
+    }
+    if( p->zLanguageid ){
+      fts3Appendf(pRc, &zRet, ", x.%Q", p->zLanguageid);
+    }
+  }
+  fts3Appendf(pRc, &zRet, " FROM '%q'.'%q%s' AS x",
+      p->zDb,
+      (p->zContentTbl ? p->zContentTbl : p->zName),
+      (p->zContentTbl ? "" : "_content")
+  );
+  return zRet;
+}
+
+/*
+** Return a list of N comma separated question marks, where N is the number
+** of columns in the %_content table (one for the docid plus one for each
+** user-defined text column).
+**
+** If argument zFunc is not NULL, then all but the first question mark
+** is preceded by zFunc and an open bracket, and followed by a closed
+** bracket. For example, if zFunc is "zip" and the FTS3 table has three
+** user-defined text columns, the following string is returned:
+**
+**     "?, zip(?), zip(?), zip(?)"
+**
+** The pointer returned points to a buffer allocated by sqlite3_malloc(). It
+** is the responsibility of the caller to eventually free it.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
+** a NULL pointer is returned). Otherwise, if an OOM error is encountered
+** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
+** no error occurs, *pRc is left unmodified.
+*/
+static char *fts3WriteExprList(Fts3Table *p, const char *zFunc, int *pRc){
+  char *zRet = 0;
+  char *zFree = 0;
+  char *zFunction;
+  int i;
+
+  if( !zFunc ){
+    zFunction = "";
+  }else{
+    zFree = zFunction = fts3QuoteId(zFunc);
+  }
+  fts3Appendf(pRc, &zRet, "?");
+  for(i=0; i<p->nColumn; i++){
+    fts3Appendf(pRc, &zRet, ",%s(?)", zFunction);
+  }
+  if( p->zLanguageid ){
+    fts3Appendf(pRc, &zRet, ", ?");
+  }
+  sqlite3_free(zFree);
+  return zRet;
+}
+
+/*
+** Buffer z contains a positive integer value encoded as utf-8 text.
+** Decode this value and store it in *pnOut, returning the number of bytes
+** consumed. If an overflow error occurs return a negative value.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ReadInt(const char *z, int *pnOut){
+  u64 iVal = 0;
+  int i;
+  for(i=0; z[i]>='0' && z[i]<='9'; i++){
+    iVal = iVal*10 + (z[i] - '0');
+    if( iVal>0x7FFFFFFF ) return -1;
+  }
+  *pnOut = (int)iVal;
+  return i;
+}
+
+/*
+** This function interprets the string at (*pp) as a non-negative integer
+** value. It reads the integer and sets *pnOut to the value read, then
+** sets *pp to point to the byte immediately following the last byte of
+** the integer value.
+**
+** Only decimal digits ('0'..'9') may be part of an integer value.
+**
+** If *pp does not being with a decimal digit SQLITE_ERROR is returned and
+** the output value undefined. Otherwise SQLITE_OK is returned.
+**
+** This function is used when parsing the "prefix=" FTS4 parameter.
+*/
+static int fts3GobbleInt(const char **pp, int *pnOut){
+  const int MAX_NPREFIX = 10000000;
+  int nInt = 0;                   /* Output value */
+  int nByte;
+  nByte = sqlite3Fts3ReadInt(*pp, &nInt);
+  if( nInt>MAX_NPREFIX ){
+    nInt = 0;
+  }
+  if( nByte==0 ){
+    return SQLITE_ERROR;
+  }
+  *pnOut = nInt;
+  *pp += nByte;
+  return SQLITE_OK;
+}
+
+/*
+** This function is called to allocate an array of Fts3Index structures
+** representing the indexes maintained by the current FTS table. FTS tables
+** always maintain the main "terms" index, but may also maintain one or
+** more "prefix" indexes, depending on the value of the "prefix=" parameter
+** (if any) specified as part of the CREATE VIRTUAL TABLE statement.
+**
+** Argument zParam is passed the value of the "prefix=" option if one was
+** specified, or NULL otherwise.
+**
+** If no error occurs, SQLITE_OK is returned and *apIndex set to point to
+** the allocated array. *pnIndex is set to the number of elements in the
+** array. If an error does occur, an SQLite error code is returned.
+**
+** Regardless of whether or not an error is returned, it is the responsibility
+** of the caller to call sqlite3_free() on the output array to free it.
+*/
+static int fts3PrefixParameter(
+  const char *zParam,             /* ABC in prefix=ABC parameter to parse */
+  int *pnIndex,                   /* OUT: size of *apIndex[] array */
+  struct Fts3Index **apIndex      /* OUT: Array of indexes for this table */
+){
+  struct Fts3Index *aIndex;       /* Allocated array */
+  int nIndex = 1;                 /* Number of entries in array */
+
+  if( zParam && zParam[0] ){
+    const char *p;
+    nIndex++;
+    for(p=zParam; *p; p++){
+      if( *p==',' ) nIndex++;
+    }
+  }
+
+  aIndex = sqlite3_malloc64(sizeof(struct Fts3Index) * nIndex);
+  *apIndex = aIndex;
+  if( !aIndex ){
+    return SQLITE_NOMEM;
+  }
+
+  memset(aIndex, 0, sizeof(struct Fts3Index) * nIndex);
+  if( zParam ){
+    const char *p = zParam;
+    int i;
+    for(i=1; i<nIndex; i++){
+      int nPrefix = 0;
+      if( fts3GobbleInt(&p, &nPrefix) ) return SQLITE_ERROR;
+      assert( nPrefix>=0 );
+      if( nPrefix==0 ){
+        nIndex--;
+        i--;
+      }else{
+        aIndex[i].nPrefix = nPrefix;
+      }
+      p++;
+    }
+  }
+
+  *pnIndex = nIndex;
+  return SQLITE_OK;
+}
+
+/*
+** This function is called when initializing an FTS4 table that uses the
+** content=xxx option. It determines the number of and names of the columns
+** of the new FTS4 table.
+**
+** The third argument passed to this function is the value passed to the
+** config=xxx option (i.e. "xxx"). This function queries the database for
+** a table of that name. If found, the output variables are populated
+** as follows:
+**
+**   *pnCol:   Set to the number of columns table xxx has,
+**
+**   *pnStr:   Set to the total amount of space required to store a copy
+**             of each columns name, including the nul-terminator.
+**
+**   *pazCol:  Set to point to an array of *pnCol strings. Each string is
+**             the name of the corresponding column in table xxx. The array
+**             and its contents are allocated using a single allocation. It
+**             is the responsibility of the caller to free this allocation
+**             by eventually passing the *pazCol value to sqlite3_free().
+**
+** If the table cannot be found, an error code is returned and the output
+** variables are undefined. Or, if an OOM is encountered, SQLITE_NOMEM is
+** returned (and the output variables are undefined).
+*/
+static int fts3ContentColumns(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of db (i.e. "main", "temp" etc.) */
+  const char *zTbl,               /* Name of content table */
+  const char ***pazCol,           /* OUT: Malloc'd array of column names */
+  int *pnCol,                     /* OUT: Size of array *pazCol */
+  int *pnStr,                     /* OUT: Bytes of string content */
+  char **pzErr                    /* OUT: error message */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  char *zSql;                     /* "SELECT *" statement on zTbl */
+  sqlite3_stmt *pStmt = 0;        /* Compiled version of zSql */
+
+  zSql = sqlite3_mprintf("SELECT * FROM %Q.%Q", zDb, zTbl);
+  if( !zSql ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+    if( rc!=SQLITE_OK ){
+      sqlite3Fts3ErrMsg(pzErr, "%s", sqlite3_errmsg(db));
+    }
+  }
+  sqlite3_free(zSql);
+
+  if( rc==SQLITE_OK ){
+    const char **azCol;           /* Output array */
+    sqlite3_int64 nStr = 0;       /* Size of all column names (incl. 0x00) */
+    int nCol;                     /* Number of table columns */
+    int i;                        /* Used to iterate through columns */
+
+    /* Loop through the returned columns. Set nStr to the number of bytes of
+    ** space required to store a copy of each column name, including the
+    ** nul-terminator byte.  */
+    nCol = sqlite3_column_count(pStmt);
+    for(i=0; i<nCol; i++){
+      const char *zCol = sqlite3_column_name(pStmt, i);
+      nStr += strlen(zCol) + 1;
+    }
+
+    /* Allocate and populate the array to return. */
+    azCol = (const char **)sqlite3_malloc64(sizeof(char *) * nCol + nStr);
+    if( azCol==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      char *p = (char *)&azCol[nCol];
+      for(i=0; i<nCol; i++){
+        const char *zCol = sqlite3_column_name(pStmt, i);
+        int n = (int)strlen(zCol)+1;
+        memcpy(p, zCol, n);
+        azCol[i] = p;
+        p += n;
+      }
+    }
+    sqlite3_finalize(pStmt);
+
+    /* Set the output variables. */
+    *pnCol = nCol;
+    *pnStr = nStr;
+    *pazCol = azCol;
+  }
+
+  return rc;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the FTS3 virtual table.
+**
+** The argv[] array contains the following:
+**
+**   argv[0]   -> module name  ("fts3" or "fts4")
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> "column name" and other module argument fields.
+*/
+static int fts3InitVtab(
+  int isCreate,                   /* True for xCreate, false for xConnect */
+  sqlite3 *db,                    /* The SQLite database connection */
+  void *pAux,                     /* Hash table containing tokenizers */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
+  char **pzErr                    /* Write any error message here */
+){
+  Fts3Hash *pHash = &((Fts3HashWrapper*)pAux)->hash;
+  Fts3Table *p = 0;               /* Pointer to allocated vtab */
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Iterator variable */
+  sqlite3_int64 nByte;            /* Size of allocation used for *p */
+  int iCol;                       /* Column index */
+  int nString = 0;                /* Bytes required to hold all column names */
+  int nCol = 0;                   /* Number of columns in the FTS table */
+  char *zCsr;                     /* Space for holding column names */
+  int nDb;                        /* Bytes required to hold database name */
+  int nName;                      /* Bytes required to hold table name */
+  int isFts4 = (argv[0][3]=='4'); /* True for FTS4, false for FTS3 */
+  const char **aCol;              /* Array of column names */
+  sqlite3_tokenizer *pTokenizer = 0;        /* Tokenizer for this table */
+
+  int nIndex = 0;                 /* Size of aIndex[] array */
+  struct Fts3Index *aIndex = 0;   /* Array of indexes for this table */
+
+  /* The results of parsing supported FTS4 key=value options: */
+  int bNoDocsize = 0;             /* True to omit %_docsize table */
+  int bDescIdx = 0;               /* True to store descending indexes */
+  char *zPrefix = 0;              /* Prefix parameter value (or NULL) */
+  char *zCompress = 0;            /* compress=? parameter (or NULL) */
+  char *zUncompress = 0;          /* uncompress=? parameter (or NULL) */
+  char *zContent = 0;             /* content=? parameter (or NULL) */
+  char *zLanguageid = 0;          /* languageid=? parameter (or NULL) */
+  char **azNotindexed = 0;        /* The set of notindexed= columns */
+  int nNotindexed = 0;            /* Size of azNotindexed[] array */
+
+  assert( strlen(argv[0])==4 );
+  assert( (sqlite3_strnicmp(argv[0], "fts4", 4)==0 && isFts4)
+       || (sqlite3_strnicmp(argv[0], "fts3", 4)==0 && !isFts4)
+  );
+
+  nDb = (int)strlen(argv[1]) + 1;
+  nName = (int)strlen(argv[2]) + 1;
+
+  nByte = sizeof(const char *) * (argc-2);
+  aCol = (const char **)sqlite3_malloc64(nByte);
+  if( aCol ){
+    memset((void*)aCol, 0, nByte);
+    azNotindexed = (char **)sqlite3_malloc64(nByte);
+  }
+  if( azNotindexed ){
+    memset(azNotindexed, 0, nByte);
+  }
+  if( !aCol || !azNotindexed ){
+    rc = SQLITE_NOMEM;
+    goto fts3_init_out;
+  }
+
+  /* Loop through all of the arguments passed by the user to the FTS3/4
+  ** module (i.e. all the column names and special arguments). This loop
+  ** does the following:
+  **
+  **   + Figures out the number of columns the FTSX table will have, and
+  **     the number of bytes of space that must be allocated to store copies
+  **     of the column names.
+  **
+  **   + If there is a tokenizer specification included in the arguments,
+  **     initializes the tokenizer pTokenizer.
+  */
+  for(i=3; rc==SQLITE_OK && i<argc; i++){
+    char const *z = argv[i];
+    int nKey;
+    char *zVal;
+
+    /* Check if this is a tokenizer specification */
+    if( !pTokenizer
+     && strlen(z)>8
+     && 0==sqlite3_strnicmp(z, "tokenize", 8)
+     && 0==sqlite3Fts3IsIdChar(z[8])
+    ){
+      rc = sqlite3Fts3InitTokenizer(pHash, &z[9], &pTokenizer, pzErr);
+    }
+
+    /* Check if it is an FTS4 special argument. */
+    else if( isFts4 && fts3IsSpecialColumn(z, &nKey, &zVal) ){
+      struct Fts4Option {
+        const char *zOpt;
+        int nOpt;
+      } aFts4Opt[] = {
+        { "matchinfo",   9 },     /* 0 -> MATCHINFO */
+        { "prefix",      6 },     /* 1 -> PREFIX */
+        { "compress",    8 },     /* 2 -> COMPRESS */
+        { "uncompress", 10 },     /* 3 -> UNCOMPRESS */
+        { "order",       5 },     /* 4 -> ORDER */
+        { "content",     7 },     /* 5 -> CONTENT */
+        { "languageid", 10 },     /* 6 -> LANGUAGEID */
+        { "notindexed", 10 }      /* 7 -> NOTINDEXED */
+      };
+
+      int iOpt;
+      if( !zVal ){
+        rc = SQLITE_NOMEM;
+      }else{
+        for(iOpt=0; iOpt<SizeofArray(aFts4Opt); iOpt++){
+          struct Fts4Option *pOp = &aFts4Opt[iOpt];
+          if( nKey==pOp->nOpt && !sqlite3_strnicmp(z, pOp->zOpt, pOp->nOpt) ){
+            break;
+          }
+        }
+        switch( iOpt ){
+          case 0:               /* MATCHINFO */
+            if( strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "fts3", 4) ){
+              sqlite3Fts3ErrMsg(pzErr, "unrecognized matchinfo: %s", zVal);
+              rc = SQLITE_ERROR;
+            }
+            bNoDocsize = 1;
+            break;
+
+          case 1:               /* PREFIX */
+            sqlite3_free(zPrefix);
+            zPrefix = zVal;
+            zVal = 0;
+            break;
+
+          case 2:               /* COMPRESS */
+            sqlite3_free(zCompress);
+            zCompress = zVal;
+            zVal = 0;
+            break;
+
+          case 3:               /* UNCOMPRESS */
+            sqlite3_free(zUncompress);
+            zUncompress = zVal;
+            zVal = 0;
+            break;
+
+          case 4:               /* ORDER */
+            if( (strlen(zVal)!=3 || sqlite3_strnicmp(zVal, "asc", 3))
+             && (strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "desc", 4))
+            ){
+              sqlite3Fts3ErrMsg(pzErr, "unrecognized order: %s", zVal);
+              rc = SQLITE_ERROR;
+            }
+            bDescIdx = (zVal[0]=='d' || zVal[0]=='D');
+            break;
+
+          case 5:              /* CONTENT */
+            sqlite3_free(zContent);
+            zContent = zVal;
+            zVal = 0;
+            break;
+
+          case 6:              /* LANGUAGEID */
+            assert( iOpt==6 );
+            sqlite3_free(zLanguageid);
+            zLanguageid = zVal;
+            zVal = 0;
+            break;
+
+          case 7:              /* NOTINDEXED */
+            azNotindexed[nNotindexed++] = zVal;
+            zVal = 0;
+            break;
+
+          default:
+            assert( iOpt==SizeofArray(aFts4Opt) );
+            sqlite3Fts3ErrMsg(pzErr, "unrecognized parameter: %s", z);
+            rc = SQLITE_ERROR;
+            break;
+        }
+        sqlite3_free(zVal);
+      }
+    }
+
+    /* Otherwise, the argument is a column name. */
+    else {
+      nString += (int)(strlen(z) + 1);
+      aCol[nCol++] = z;
+    }
+  }
+
+  /* If a content=xxx option was specified, the following:
+  **
+  **   1. Ignore any compress= and uncompress= options.
+  **
+  **   2. If no column names were specified as part of the CREATE VIRTUAL
+  **      TABLE statement, use all columns from the content table.
+  */
+  if( rc==SQLITE_OK && zContent ){
+    sqlite3_free(zCompress);
+    sqlite3_free(zUncompress);
+    zCompress = 0;
+    zUncompress = 0;
+    if( nCol==0 ){
+      sqlite3_free((void*)aCol);
+      aCol = 0;
+      rc = fts3ContentColumns(db, argv[1], zContent,&aCol,&nCol,&nString,pzErr);
+
+      /* If a languageid= option was specified, remove the language id
+      ** column from the aCol[] array. */
+      if( rc==SQLITE_OK && zLanguageid ){
+        int j;
+        for(j=0; j<nCol; j++){
+          if( sqlite3_stricmp(zLanguageid, aCol[j])==0 ){
+            int k;
+            for(k=j; k<nCol; k++) aCol[k] = aCol[k+1];
+            nCol--;
+            break;
+          }
+        }
+      }
+    }
+  }
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  if( nCol==0 ){
+    assert( nString==0 );
+    aCol[0] = "content";
+    nString = 8;
+    nCol = 1;
+  }
+
+  if( pTokenizer==0 ){
+    rc = sqlite3Fts3InitTokenizer(pHash, "simple", &pTokenizer, pzErr);
+    if( rc!=SQLITE_OK ) goto fts3_init_out;
+  }
+  assert( pTokenizer );
+
+  rc = fts3PrefixParameter(zPrefix, &nIndex, &aIndex);
+  if( rc==SQLITE_ERROR ){
+    assert( zPrefix );
+    sqlite3Fts3ErrMsg(pzErr, "error parsing prefix parameter: %s", zPrefix);
+  }
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  /* Allocate and populate the Fts3Table structure. */
+  nByte = sizeof(Fts3Table) +                  /* Fts3Table */
+          nCol * sizeof(char *) +              /* azColumn */
+          nIndex * sizeof(struct Fts3Index) +  /* aIndex */
+          nCol * sizeof(u8) +                  /* abNotindexed */
+          nName +                              /* zName */
+          nDb +                                /* zDb */
+          nString;                             /* Space for azColumn strings */
+  p = (Fts3Table*)sqlite3_malloc64(nByte);
+  if( p==0 ){
+    rc = SQLITE_NOMEM;
+    goto fts3_init_out;
+  }
+  memset(p, 0, nByte);
+  p->db = db;
+  p->nColumn = nCol;
+  p->nPendingData = 0;
+  p->azColumn = (char **)&p[1];
+  p->pTokenizer = pTokenizer;
+  p->nMaxPendingData = FTS3_MAX_PENDING_DATA;
+  p->bHasDocsize = (isFts4 && bNoDocsize==0);
+  p->bHasStat = (u8)isFts4;
+  p->bFts4 = (u8)isFts4;
+  p->bDescIdx = (u8)bDescIdx;
+  p->nAutoincrmerge = 0xff;   /* 0xff means setting unknown */
+  p->zContentTbl = zContent;
+  p->zLanguageid = zLanguageid;
+  zContent = 0;
+  zLanguageid = 0;
+  TESTONLY( p->inTransaction = -1 );
+  TESTONLY( p->mxSavepoint = -1 );
+
+  p->aIndex = (struct Fts3Index *)&p->azColumn[nCol];
+  memcpy(p->aIndex, aIndex, sizeof(struct Fts3Index) * nIndex);
+  p->nIndex = nIndex;
+  for(i=0; i<nIndex; i++){
+    fts3HashInit(&p->aIndex[i].hPending, FTS3_HASH_STRING, 1);
+  }
+  p->abNotindexed = (u8 *)&p->aIndex[nIndex];
+
+  /* Fill in the zName and zDb fields of the vtab structure. */
+  zCsr = (char *)&p->abNotindexed[nCol];
+  p->zName = zCsr;
+  memcpy(zCsr, argv[2], nName);
+  zCsr += nName;
+  p->zDb = zCsr;
+  memcpy(zCsr, argv[1], nDb);
+  zCsr += nDb;
+
+  /* Fill in the azColumn array */
+  for(iCol=0; iCol<nCol; iCol++){
+    char *z;
+    int n = 0;
+    z = (char *)sqlite3Fts3NextToken(aCol[iCol], &n);
+    if( n>0 ){
+      memcpy(zCsr, z, n);
+    }
+    zCsr[n] = '\0';
+    sqlite3Fts3Dequote(zCsr);
+    p->azColumn[iCol] = zCsr;
+    zCsr += n+1;
+    assert( zCsr <= &((char *)p)[nByte] );
+  }
+
+  /* Fill in the abNotindexed array */
+  for(iCol=0; iCol<nCol; iCol++){
+    int n = (int)strlen(p->azColumn[iCol]);
+    for(i=0; i<nNotindexed; i++){
+      char *zNot = azNotindexed[i];
+      if( zNot && n==(int)strlen(zNot)
+       && 0==sqlite3_strnicmp(p->azColumn[iCol], zNot, n)
+      ){
+        p->abNotindexed[iCol] = 1;
+        sqlite3_free(zNot);
+        azNotindexed[i] = 0;
+      }
+    }
+  }
+  for(i=0; i<nNotindexed; i++){
+    if( azNotindexed[i] ){
+      sqlite3Fts3ErrMsg(pzErr, "no such column: %s", azNotindexed[i]);
+      rc = SQLITE_ERROR;
+    }
+  }
+
+  if( rc==SQLITE_OK && (zCompress==0)!=(zUncompress==0) ){
+    char const *zMiss = (zCompress==0 ? "compress" : "uncompress");
+    rc = SQLITE_ERROR;
+    sqlite3Fts3ErrMsg(pzErr, "missing %s parameter in fts4 constructor", zMiss);
+  }
+  p->zReadExprlist = fts3ReadExprList(p, zUncompress, &rc);
+  p->zWriteExprlist = fts3WriteExprList(p, zCompress, &rc);
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  /* If this is an xCreate call, create the underlying tables in the
+  ** database. TODO: For xConnect(), it could verify that said tables exist.
+  */
+  if( isCreate ){
+    rc = fts3CreateTables(p);
+  }
+
+  /* Check to see if a legacy fts3 table has been "upgraded" by the
+  ** addition of a %_stat table so that it can use incremental merge.
+  */
+  if( !isFts4 && !isCreate ){
+    p->bHasStat = 2;
+  }
+
+  /* Figure out the page-size for the database. This is required in order to
+  ** estimate the cost of loading large doclists from the database.  */
+  fts3DatabasePageSize(&rc, p);
+  p->nNodeSize = p->nPgsz-35;
+
+#if defined(SQLITE_DEBUG)||defined(SQLITE_TEST)
+  p->nMergeCount = FTS3_MERGE_COUNT;
+#endif
+
+  /* Declare the table schema to SQLite. */
+  fts3DeclareVtab(&rc, p);
+
+fts3_init_out:
+  sqlite3_free(zPrefix);
+  sqlite3_free(aIndex);
+  sqlite3_free(zCompress);
+  sqlite3_free(zUncompress);
+  sqlite3_free(zContent);
+  sqlite3_free(zLanguageid);
+  for(i=0; i<nNotindexed; i++) sqlite3_free(azNotindexed[i]);
+  sqlite3_free((void *)aCol);
+  sqlite3_free((void *)azNotindexed);
+  if( rc!=SQLITE_OK ){
+    if( p ){
+      fts3DisconnectMethod((sqlite3_vtab *)p);
+    }else if( pTokenizer ){
+      pTokenizer->pModule->xDestroy(pTokenizer);
+    }
+  }else{
+    assert( p->pSegments==0 );
+    *ppVTab = &p->base;
+  }
+  return rc;
+}
+
+/*
+** The xConnect() and xCreate() methods for the virtual table. All the
+** work is done in function fts3InitVtab().
+*/
+static int fts3ConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts3InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr);
+}
+static int fts3CreateMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts3InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr);
+}
+
+/*
+** Set the pIdxInfo->estimatedRows variable to nRow. Unless this
+** extension is currently being used by a version of SQLite too old to
+** support estimatedRows. In that case this function is a no-op.
+*/
+static void fts3SetEstimatedRows(sqlite3_index_info *pIdxInfo, i64 nRow){
+#if SQLITE_VERSION_NUMBER>=3008002
+  if( sqlite3_libversion_number()>=3008002 ){
+    pIdxInfo->estimatedRows = nRow;
+  }
+#endif
+}
+
+/*
+** Set the SQLITE_INDEX_SCAN_UNIQUE flag in pIdxInfo->flags. Unless this
+** extension is currently being used by a version of SQLite too old to
+** support index-info flags. In that case this function is a no-op.
+*/
+static void fts3SetUniqueFlag(sqlite3_index_info *pIdxInfo){
+#if SQLITE_VERSION_NUMBER>=3008012
+  if( sqlite3_libversion_number()>=3008012 ){
+    pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_UNIQUE;
+  }
+#endif
+}
+
+/*
+** Implementation of the xBestIndex method for FTS3 tables. There
+** are three possible strategies, in order of preference:
+**
+**   1. Direct lookup by rowid or docid.
+**   2. Full-text search using a MATCH operator on a non-docid column.
+**   3. Linear scan of %_content table.
+*/
+static int fts3BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
+  Fts3Table *p = (Fts3Table *)pVTab;
+  int i;                          /* Iterator variable */
+  int iCons = -1;                 /* Index of constraint to use */
+
+  int iLangidCons = -1;           /* Index of langid=x constraint, if present */
+  int iDocidGe = -1;              /* Index of docid>=x constraint, if present */
+  int iDocidLe = -1;              /* Index of docid<=x constraint, if present */
+  int iIdx;
+
+  if( p->bLock ){
+    return SQLITE_ERROR;
+  }
+
+  /* By default use a full table scan. This is an expensive option,
+  ** so search through the constraints to see if a more efficient
+  ** strategy is possible.
+  */
+  pInfo->idxNum = FTS3_FULLSCAN_SEARCH;
+  pInfo->estimatedCost = 5000000;
+  for(i=0; i<pInfo->nConstraint; i++){
+    int bDocid;                 /* True if this constraint is on docid */
+    struct sqlite3_index_constraint *pCons = &pInfo->aConstraint[i];
+    if( pCons->usable==0 ){
+      if( pCons->op==SQLITE_INDEX_CONSTRAINT_MATCH ){
+        /* There exists an unusable MATCH constraint. This means that if
+        ** the planner does elect to use the results of this call as part
+        ** of the overall query plan the user will see an "unable to use
+        ** function MATCH in the requested context" error. To discourage
+        ** this, return a very high cost here.  */
+        pInfo->idxNum = FTS3_FULLSCAN_SEARCH;
+        pInfo->estimatedCost = 1e50;
+        fts3SetEstimatedRows(pInfo, ((sqlite3_int64)1) << 50);
+        return SQLITE_OK;
+      }
+      continue;
+    }
+
+    bDocid = (pCons->iColumn<0 || pCons->iColumn==p->nColumn+1);
+
+    /* A direct lookup on the rowid or docid column. Assign a cost of 1.0. */
+    if( iCons<0 && pCons->op==SQLITE_INDEX_CONSTRAINT_EQ && bDocid ){
+      pInfo->idxNum = FTS3_DOCID_SEARCH;
+      pInfo->estimatedCost = 1.0;
+      iCons = i;
+    }
+
+    /* A MATCH constraint. Use a full-text search.
+    **
+    ** If there is more than one MATCH constraint available, use the first
+    ** one encountered. If there is both a MATCH constraint and a direct
+    ** rowid/docid lookup, prefer the MATCH strategy. This is done even
+    ** though the rowid/docid lookup is faster than a MATCH query, selecting
+    ** it would lead to an "unable to use function MATCH in the requested
+    ** context" error.
+    */
+    if( pCons->op==SQLITE_INDEX_CONSTRAINT_MATCH
+     && pCons->iColumn>=0 && pCons->iColumn<=p->nColumn
+    ){
+      pInfo->idxNum = FTS3_FULLTEXT_SEARCH + pCons->iColumn;
+      pInfo->estimatedCost = 2.0;
+      iCons = i;
+    }
+
+    /* Equality constraint on the langid column */
+    if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ
+     && pCons->iColumn==p->nColumn + 2
+    ){
+      iLangidCons = i;
+    }
+
+    if( bDocid ){
+      switch( pCons->op ){
+        case SQLITE_INDEX_CONSTRAINT_GE:
+        case SQLITE_INDEX_CONSTRAINT_GT:
+          iDocidGe = i;
+          break;
+
+        case SQLITE_INDEX_CONSTRAINT_LE:
+        case SQLITE_INDEX_CONSTRAINT_LT:
+          iDocidLe = i;
+          break;
+      }
+    }
+  }
+
+  /* If using a docid=? or rowid=? strategy, set the UNIQUE flag. */
+  if( pInfo->idxNum==FTS3_DOCID_SEARCH ) fts3SetUniqueFlag(pInfo);
+
+  iIdx = 1;
+  if( iCons>=0 ){
+    pInfo->aConstraintUsage[iCons].argvIndex = iIdx++;
+    pInfo->aConstraintUsage[iCons].omit = 1;
+  }
+  if( iLangidCons>=0 ){
+    pInfo->idxNum |= FTS3_HAVE_LANGID;
+    pInfo->aConstraintUsage[iLangidCons].argvIndex = iIdx++;
+  }
+  if( iDocidGe>=0 ){
+    pInfo->idxNum |= FTS3_HAVE_DOCID_GE;
+    pInfo->aConstraintUsage[iDocidGe].argvIndex = iIdx++;
+  }
+  if( iDocidLe>=0 ){
+    pInfo->idxNum |= FTS3_HAVE_DOCID_LE;
+    pInfo->aConstraintUsage[iDocidLe].argvIndex = iIdx++;
+  }
+
+  /* Regardless of the strategy selected, FTS can deliver rows in rowid (or
+  ** docid) order. Both ascending and descending are possible.
+  */
+  if( pInfo->nOrderBy==1 ){
+    struct sqlite3_index_orderby *pOrder = &pInfo->aOrderBy[0];
+    if( pOrder->iColumn<0 || pOrder->iColumn==p->nColumn+1 ){
+      if( pOrder->desc ){
+        pInfo->idxStr = "DESC";
+      }else{
+        pInfo->idxStr = "ASC";
+      }
+      pInfo->orderByConsumed = 1;
+    }
+  }
+
+  assert( p->pSegments==0 );
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xOpen method.
+*/
+static int fts3OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  sqlite3_vtab_cursor *pCsr;               /* Allocated cursor */
+
+  UNUSED_PARAMETER(pVTab);
+
+  /* Allocate a buffer large enough for an Fts3Cursor structure. If the
+  ** allocation succeeds, zero it and return SQLITE_OK. Otherwise,
+  ** if the allocation fails, return SQLITE_NOMEM.
+  */
+  *ppCsr = pCsr = (sqlite3_vtab_cursor *)sqlite3_malloc(sizeof(Fts3Cursor));
+  if( !pCsr ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(Fts3Cursor));
+  return SQLITE_OK;
+}
+
+/*
+** Finalize the statement handle at pCsr->pStmt.
+**
+** Or, if that statement handle is one created by fts3CursorSeekStmt(),
+** and the Fts3Table.pSeekStmt slot is currently NULL, save the statement
+** pointer there instead of finalizing it.
+*/
+static void fts3CursorFinalizeStmt(Fts3Cursor *pCsr){
+  if( pCsr->bSeekStmt ){
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+    if( p->pSeekStmt==0 ){
+      p->pSeekStmt = pCsr->pStmt;
+      sqlite3_reset(pCsr->pStmt);
+      pCsr->pStmt = 0;
+    }
+    pCsr->bSeekStmt = 0;
+  }
+  sqlite3_finalize(pCsr->pStmt);
+}
+
+/*
+** Free all resources currently held by the cursor passed as the only
+** argument.
+*/
+static void fts3ClearCursor(Fts3Cursor *pCsr){
+  fts3CursorFinalizeStmt(pCsr);
+  sqlite3Fts3FreeDeferredTokens(pCsr);
+  sqlite3_free(pCsr->aDoclist);
+  sqlite3Fts3MIBufferFree(pCsr->pMIBuffer);
+  sqlite3Fts3ExprFree(pCsr->pExpr);
+  memset(&(&pCsr->base)[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor));
+}
+
+/*
+** Close the cursor.  For additional information see the documentation
+** on the xClose method of the virtual table interface.
+*/
+static int fts3CloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  fts3ClearCursor(pCsr);
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** If pCsr->pStmt has not been prepared (i.e. if pCsr->pStmt==0), then
+** compose and prepare an SQL statement of the form:
+**
+**    "SELECT <columns> FROM %_content WHERE rowid = ?"
+**
+** (or the equivalent for a content=xxx table) and set pCsr->pStmt to
+** it. If an error occurs, return an SQLite error code.
+*/
+static int fts3CursorSeekStmt(Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;
+  if( pCsr->pStmt==0 ){
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+    char *zSql;
+    if( p->pSeekStmt ){
+      pCsr->pStmt = p->pSeekStmt;
+      p->pSeekStmt = 0;
+    }else{
+      zSql = sqlite3_mprintf("SELECT %s WHERE rowid = ?", p->zReadExprlist);
+      if( !zSql ) return SQLITE_NOMEM;
+      p->bLock++;
+      rc = sqlite3_prepare_v3(
+          p->db, zSql,-1,SQLITE_PREPARE_PERSISTENT,&pCsr->pStmt,0
+      );
+      p->bLock--;
+      sqlite3_free(zSql);
+    }
+    if( rc==SQLITE_OK ) pCsr->bSeekStmt = 1;
+  }
+  return rc;
+}
+
+/*
+** Position the pCsr->pStmt statement so that it is on the row
+** of the %_content table that contains the last match.  Return
+** SQLITE_OK on success.
+*/
+static int fts3CursorSeek(sqlite3_context *pContext, Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;
+  if( pCsr->isRequireSeek ){
+    rc = fts3CursorSeekStmt(pCsr);
+    if( rc==SQLITE_OK ){
+      Fts3Table *pTab = (Fts3Table*)pCsr->base.pVtab;
+      pTab->bLock++;
+      sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);
+      pCsr->isRequireSeek = 0;
+      if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){
+        pTab->bLock--;
+        return SQLITE_OK;
+      }else{
+        pTab->bLock--;
+        rc = sqlite3_reset(pCsr->pStmt);
+        if( rc==SQLITE_OK && ((Fts3Table *)pCsr->base.pVtab)->zContentTbl==0 ){
+          /* If no row was found and no error has occurred, then the %_content
+          ** table is missing a row that is present in the full-text index.
+          ** The data structures are corrupt.  */
+          rc = FTS_CORRUPT_VTAB;
+          pCsr->isEof = 1;
+        }
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK && pContext ){
+    sqlite3_result_error_code(pContext, rc);
+  }
+  return rc;
+}
+
+/*
+** This function is used to process a single interior node when searching
+** a b-tree for a term or term prefix. The node data is passed to this
+** function via the zNode/nNode parameters. The term to search for is
+** passed in zTerm/nTerm.
+**
+** If piFirst is not NULL, then this function sets *piFirst to the blockid
+** of the child node that heads the sub-tree that may contain the term.
+**
+** If piLast is not NULL, then *piLast is set to the right-most child node
+** that heads a sub-tree that may contain a term for which zTerm/nTerm is
+** a prefix.
+**
+** If an OOM error occurs, SQLITE_NOMEM is returned. Otherwise, SQLITE_OK.
+*/
+static int fts3ScanInteriorNode(
+  const char *zTerm,              /* Term to select leaves for */
+  int nTerm,                      /* Size of term zTerm in bytes */
+  const char *zNode,              /* Buffer containing segment interior node */
+  int nNode,                      /* Size of buffer at zNode */
+  sqlite3_int64 *piFirst,         /* OUT: Selected child node */
+  sqlite3_int64 *piLast           /* OUT: Selected child node */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  const char *zCsr = zNode;       /* Cursor to iterate through node */
+  const char *zEnd = &zCsr[nNode];/* End of interior node buffer */
+  char *zBuffer = 0;              /* Buffer to load terms into */
+  i64 nAlloc = 0;                 /* Size of allocated buffer */
+  int isFirstTerm = 1;            /* True when processing first term on page */
+  u64 iChild;                     /* Block id of child node to descend to */
+  int nBuffer = 0;                /* Total term size */
+
+  /* Skip over the 'height' varint that occurs at the start of every
+  ** interior node. Then load the blockid of the left-child of the b-tree
+  ** node into variable iChild.
+  **
+  ** Even if the data structure on disk is corrupted, this (reading two
+  ** varints from the buffer) does not risk an overread. If zNode is a
+  ** root node, then the buffer comes from a SELECT statement. SQLite does
+  ** not make this guarantee explicitly, but in practice there are always
+  ** either more than 20 bytes of allocated space following the nNode bytes of
+  ** contents, or two zero bytes. Or, if the node is read from the %_segments
+  ** table, then there are always 20 bytes of zeroed padding following the
+  ** nNode bytes of content (see sqlite3Fts3ReadBlock() for details).
+  */
+  zCsr += sqlite3Fts3GetVarintU(zCsr, &iChild);
+  zCsr += sqlite3Fts3GetVarintU(zCsr, &iChild);
+  if( zCsr>zEnd ){
+    return FTS_CORRUPT_VTAB;
+  }
+
+  while( zCsr<zEnd && (piFirst || piLast) ){
+    int cmp;                      /* memcmp() result */
+    int nSuffix;                  /* Size of term suffix */
+    int nPrefix = 0;              /* Size of term prefix */
+
+    /* Load the next term on the node into zBuffer. Use realloc() to expand
+    ** the size of zBuffer if required.  */
+    if( !isFirstTerm ){
+      zCsr += fts3GetVarint32(zCsr, &nPrefix);
+      if( nPrefix>nBuffer ){
+        rc = FTS_CORRUPT_VTAB;
+        goto finish_scan;
+      }
+    }
+    isFirstTerm = 0;
+    zCsr += fts3GetVarint32(zCsr, &nSuffix);
+
+    assert( nPrefix>=0 && nSuffix>=0 );
+    if( nPrefix>zCsr-zNode || nSuffix>zEnd-zCsr || nSuffix==0 ){
+      rc = FTS_CORRUPT_VTAB;
+      goto finish_scan;
+    }
+    if( (i64)nPrefix+nSuffix>nAlloc ){
+      char *zNew;
+      nAlloc = ((i64)nPrefix+nSuffix) * 2;
+      zNew = (char *)sqlite3_realloc64(zBuffer, nAlloc);
+      if( !zNew ){
+        rc = SQLITE_NOMEM;
+        goto finish_scan;
+      }
+      zBuffer = zNew;
+    }
+    assert( zBuffer );
+    memcpy(&zBuffer[nPrefix], zCsr, nSuffix);
+    nBuffer = nPrefix + nSuffix;
+    zCsr += nSuffix;
+
+    /* Compare the term we are searching for with the term just loaded from
+    ** the interior node. If the specified term is greater than or equal
+    ** to the term from the interior node, then all terms on the sub-tree
+    ** headed by node iChild are smaller than zTerm. No need to search
+    ** iChild.
+    **
+    ** If the interior node term is larger than the specified term, then
+    ** the tree headed by iChild may contain the specified term.
+    */
+    cmp = memcmp(zTerm, zBuffer, (nBuffer>nTerm ? nTerm : nBuffer));
+    if( piFirst && (cmp<0 || (cmp==0 && nBuffer>nTerm)) ){
+      *piFirst = (i64)iChild;
+      piFirst = 0;
+    }
+
+    if( piLast && cmp<0 ){
+      *piLast = (i64)iChild;
+      piLast = 0;
+    }
+
+    iChild++;
+  };
+
+  if( piFirst ) *piFirst = (i64)iChild;
+  if( piLast ) *piLast = (i64)iChild;
+
+ finish_scan:
+  sqlite3_free(zBuffer);
+  return rc;
+}
+
+
+/*
+** The buffer pointed to by argument zNode (size nNode bytes) contains an
+** interior node of a b-tree segment. The zTerm buffer (size nTerm bytes)
+** contains a term. This function searches the sub-tree headed by the zNode
+** node for the range of leaf nodes that may contain the specified term
+** or terms for which the specified term is a prefix.
+**
+** If piLeaf is not NULL, then *piLeaf is set to the blockid of the
+** left-most leaf node in the tree that may contain the specified term.
+** If piLeaf2 is not NULL, then *piLeaf2 is set to the blockid of the
+** right-most leaf node that may contain a term for which the specified
+** term is a prefix.
+**
+** It is possible that the range of returned leaf nodes does not contain
+** the specified term or any terms for which it is a prefix. However, if the
+** segment does contain any such terms, they are stored within the identified
+** range. Because this function only inspects interior segment nodes (and
+** never loads leaf nodes into memory), it is not possible to be sure.
+**
+** If an error occurs, an error code other than SQLITE_OK is returned.
+*/
+static int fts3SelectLeaf(
+  Fts3Table *p,                   /* Virtual table handle */
+  const char *zTerm,              /* Term to select leaves for */
+  int nTerm,                      /* Size of term zTerm in bytes */
+  const char *zNode,              /* Buffer containing segment interior node */
+  int nNode,                      /* Size of buffer at zNode */
+  sqlite3_int64 *piLeaf,          /* Selected leaf node */
+  sqlite3_int64 *piLeaf2          /* Selected leaf node */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int iHeight;                    /* Height of this node in tree */
+
+  assert( piLeaf || piLeaf2 );
+
+  fts3GetVarint32(zNode, &iHeight);
+  rc = fts3ScanInteriorNode(zTerm, nTerm, zNode, nNode, piLeaf, piLeaf2);
+  assert_fts3_nc( !piLeaf2 || !piLeaf || rc!=SQLITE_OK || (*piLeaf<=*piLeaf2) );
+
+  if( rc==SQLITE_OK && iHeight>1 ){
+    char *zBlob = 0;              /* Blob read from %_segments table */
+    int nBlob = 0;                /* Size of zBlob in bytes */
+
+    if( piLeaf && piLeaf2 && (*piLeaf!=*piLeaf2) ){
+      rc = sqlite3Fts3ReadBlock(p, *piLeaf, &zBlob, &nBlob, 0);
+      if( rc==SQLITE_OK ){
+        rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, 0);
+      }
+      sqlite3_free(zBlob);
+      piLeaf = 0;
+      zBlob = 0;
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts3ReadBlock(p, piLeaf?*piLeaf:*piLeaf2, &zBlob, &nBlob, 0);
+    }
+    if( rc==SQLITE_OK ){
+      int iNewHeight = 0;
+      fts3GetVarint32(zBlob, &iNewHeight);
+      if( iNewHeight>=iHeight ){
+        rc = FTS_CORRUPT_VTAB;
+      }else{
+        rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, piLeaf2);
+      }
+    }
+    sqlite3_free(zBlob);
+  }
+
+  return rc;
+}
+
+/*
+** This function is used to create delta-encoded serialized lists of FTS3
+** varints. Each call to this function appends a single varint to a list.
+*/
+static void fts3PutDeltaVarint(
+  char **pp,                      /* IN/OUT: Output pointer */
+  sqlite3_int64 *piPrev,          /* IN/OUT: Previous value written to list */
+  sqlite3_int64 iVal              /* Write this value to the list */
+){
+  assert_fts3_nc( iVal-*piPrev > 0 || (*piPrev==0 && iVal==0) );
+  *pp += sqlite3Fts3PutVarint(*pp, iVal-*piPrev);
+  *piPrev = iVal;
+}
+
+/*
+** When this function is called, *ppPoslist is assumed to point to the
+** start of a position-list. After it returns, *ppPoslist points to the
+** first byte after the position-list.
+**
+** A position list is list of positions (delta encoded) and columns for
+** a single document record of a doclist.  So, in other words, this
+** routine advances *ppPoslist so that it points to the next docid in
+** the doclist, or to the first byte past the end of the doclist.
+**
+** If pp is not NULL, then the contents of the position list are copied
+** to *pp. *pp is set to point to the first byte past the last byte copied
+** before this function returns.
+*/
+static void fts3PoslistCopy(char **pp, char **ppPoslist){
+  char *pEnd = *ppPoslist;
+  char c = 0;
+
+  /* The end of a position list is marked by a zero encoded as an FTS3
+  ** varint. A single POS_END (0) byte. Except, if the 0 byte is preceded by
+  ** a byte with the 0x80 bit set, then it is not a varint 0, but the tail
+  ** of some other, multi-byte, value.
+  **
+  ** The following while-loop moves pEnd to point to the first byte that is not
+  ** immediately preceded by a byte with the 0x80 bit set. Then increments
+  ** pEnd once more so that it points to the byte immediately following the
+  ** last byte in the position-list.
+  */
+  while( *pEnd | c ){
+    c = *pEnd++ & 0x80;
+    testcase( c!=0 && (*pEnd)==0 );
+  }
+  pEnd++;  /* Advance past the POS_END terminator byte */
+
+  if( pp ){
+    int n = (int)(pEnd - *ppPoslist);
+    char *p = *pp;
+    memcpy(p, *ppPoslist, n);
+    p += n;
+    *pp = p;
+  }
+  *ppPoslist = pEnd;
+}
+
+/*
+** When this function is called, *ppPoslist is assumed to point to the
+** start of a column-list. After it returns, *ppPoslist points to the
+** to the terminator (POS_COLUMN or POS_END) byte of the column-list.
+**
+** A column-list is list of delta-encoded positions for a single column
+** within a single document within a doclist.
+**
+** The column-list is terminated either by a POS_COLUMN varint (1) or
+** a POS_END varint (0).  This routine leaves *ppPoslist pointing to
+** the POS_COLUMN or POS_END that terminates the column-list.
+**
+** If pp is not NULL, then the contents of the column-list are copied
+** to *pp. *pp is set to point to the first byte past the last byte copied
+** before this function returns.  The POS_COLUMN or POS_END terminator
+** is not copied into *pp.
+*/
+static void fts3ColumnlistCopy(char **pp, char **ppPoslist){
+  char *pEnd = *ppPoslist;
+  char c = 0;
+
+  /* A column-list is terminated by either a 0x01 or 0x00 byte that is
+  ** not part of a multi-byte varint.
+  */
+  while( 0xFE & (*pEnd | c) ){
+    c = *pEnd++ & 0x80;
+    testcase( c!=0 && ((*pEnd)&0xfe)==0 );
+  }
+  if( pp ){
+    int n = (int)(pEnd - *ppPoslist);
+    char *p = *pp;
+    memcpy(p, *ppPoslist, n);
+    p += n;
+    *pp = p;
+  }
+  *ppPoslist = pEnd;
+}
+
+/*
+** Value used to signify the end of an position-list. This must be
+** as large or larger than any value that might appear on the
+** position-list, even a position list that has been corrupted.
+*/
+#define POSITION_LIST_END LARGEST_INT64
+
+/*
+** This function is used to help parse position-lists. When this function is
+** called, *pp may point to the start of the next varint in the position-list
+** being parsed, or it may point to 1 byte past the end of the position-list
+** (in which case **pp will be a terminator bytes POS_END (0) or
+** (1)).
+**
+** If *pp points past the end of the current position-list, set *pi to
+** POSITION_LIST_END and return. Otherwise, read the next varint from *pp,
+** increment the current value of *pi by the value read, and set *pp to
+** point to the next value before returning.
+**
+** Before calling this routine *pi must be initialized to the value of
+** the previous position, or zero if we are reading the first position
+** in the position-list.  Because positions are delta-encoded, the value
+** of the previous position is needed in order to compute the value of
+** the next position.
+*/
+static void fts3ReadNextPos(
+  char **pp,                    /* IN/OUT: Pointer into position-list buffer */
+  sqlite3_int64 *pi             /* IN/OUT: Value read from position-list */
+){
+  if( (**pp)&0xFE ){
+    int iVal;
+    *pp += fts3GetVarint32((*pp), &iVal);
+    *pi += iVal;
+    *pi -= 2;
+  }else{
+    *pi = POSITION_LIST_END;
+  }
+}
+
+/*
+** If parameter iCol is not 0, write an POS_COLUMN (1) byte followed by
+** the value of iCol encoded as a varint to *pp.   This will start a new
+** column list.
+**
+** Set *pp to point to the byte just after the last byte written before
+** returning (do not modify it if iCol==0). Return the total number of bytes
+** written (0 if iCol==0).
+*/
+static int fts3PutColNumber(char **pp, int iCol){
+  int n = 0;                      /* Number of bytes written */
+  if( iCol ){
+    char *p = *pp;                /* Output pointer */
+    n = 1 + sqlite3Fts3PutVarint(&p[1], iCol);
+    *p = 0x01;
+    *pp = &p[n];
+  }
+  return n;
+}
+
+/*
+** Compute the union of two position lists.  The output written
+** into *pp contains all positions of both *pp1 and *pp2 in sorted
+** order and with any duplicates removed.  All pointers are
+** updated appropriately.   The caller is responsible for insuring
+** that there is enough space in *pp to hold the complete output.
+*/
+static int fts3PoslistMerge(
+  char **pp,                      /* Output buffer */
+  char **pp1,                     /* Left input list */
+  char **pp2                      /* Right input list */
+){
+  char *p = *pp;
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+
+  while( *p1 || *p2 ){
+    int iCol1;         /* The current column index in pp1 */
+    int iCol2;         /* The current column index in pp2 */
+
+    if( *p1==POS_COLUMN ){
+      fts3GetVarint32(&p1[1], &iCol1);
+      if( iCol1==0 ) return FTS_CORRUPT_VTAB;
+    }
+    else if( *p1==POS_END ) iCol1 = 0x7fffffff;
+    else iCol1 = 0;
+
+    if( *p2==POS_COLUMN ){
+      fts3GetVarint32(&p2[1], &iCol2);
+      if( iCol2==0 ) return FTS_CORRUPT_VTAB;
+    }
+    else if( *p2==POS_END ) iCol2 = 0x7fffffff;
+    else iCol2 = 0;
+
+    if( iCol1==iCol2 ){
+      sqlite3_int64 i1 = 0;       /* Last position from pp1 */
+      sqlite3_int64 i2 = 0;       /* Last position from pp2 */
+      sqlite3_int64 iPrev = 0;
+      int n = fts3PutColNumber(&p, iCol1);
+      p1 += n;
+      p2 += n;
+
+      /* At this point, both p1 and p2 point to the start of column-lists
+      ** for the same column (the column with index iCol1 and iCol2).
+      ** A column-list is a list of non-negative delta-encoded varints, each
+      ** incremented by 2 before being stored. Each list is terminated by a
+      ** POS_END (0) or POS_COLUMN (1). The following block merges the two lists
+      ** and writes the results to buffer p. p is left pointing to the byte
+      ** after the list written. No terminator (POS_END or POS_COLUMN) is
+      ** written to the output.
+      */
+      fts3GetDeltaVarint(&p1, &i1);
+      fts3GetDeltaVarint(&p2, &i2);
+      if( i1<2 || i2<2 ){
+        break;
+      }
+      do {
+        fts3PutDeltaVarint(&p, &iPrev, (i1<i2) ? i1 : i2);
+        iPrev -= 2;
+        if( i1==i2 ){
+          fts3ReadNextPos(&p1, &i1);
+          fts3ReadNextPos(&p2, &i2);
+        }else if( i1<i2 ){
+          fts3ReadNextPos(&p1, &i1);
+        }else{
+          fts3ReadNextPos(&p2, &i2);
+        }
+      }while( i1!=POSITION_LIST_END || i2!=POSITION_LIST_END );
+    }else if( iCol1<iCol2 ){
+      p1 += fts3PutColNumber(&p, iCol1);
+      fts3ColumnlistCopy(&p, &p1);
+    }else{
+      p2 += fts3PutColNumber(&p, iCol2);
+      fts3ColumnlistCopy(&p, &p2);
+    }
+  }
+
+  *p++ = POS_END;
+  *pp = p;
+  *pp1 = p1 + 1;
+  *pp2 = p2 + 1;
+  return SQLITE_OK;
+}
+
+/*
+** This function is used to merge two position lists into one. When it is
+** called, *pp1 and *pp2 must both point to position lists. A position-list is
+** the part of a doclist that follows each document id. For example, if a row
+** contains:
+**
+**     'a b c'|'x y z'|'a b b a'
+**
+** Then the position list for this row for token 'b' would consist of:
+**
+**     0x02 0x01 0x02 0x03 0x03 0x00
+**
+** When this function returns, both *pp1 and *pp2 are left pointing to the
+** byte following the 0x00 terminator of their respective position lists.
+**
+** If isSaveLeft is 0, an entry is added to the output position list for
+** each position in *pp2 for which there exists one or more positions in
+** *pp1 so that (pos(*pp2)>pos(*pp1) && pos(*pp2)-pos(*pp1)<=nToken). i.e.
+** when the *pp1 token appears before the *pp2 token, but not more than nToken
+** slots before it.
+**
+** e.g. nToken==1 searches for adjacent positions.
+*/
+static int fts3PoslistPhraseMerge(
+  char **pp,                      /* IN/OUT: Preallocated output buffer */
+  int nToken,                     /* Maximum difference in token positions */
+  int isSaveLeft,                 /* Save the left position */
+  int isExact,                    /* If *pp1 is exactly nTokens before *pp2 */
+  char **pp1,                     /* IN/OUT: Left input list */
+  char **pp2                      /* IN/OUT: Right input list */
+){
+  char *p = *pp;
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+  int iCol1 = 0;
+  int iCol2 = 0;
+
+  /* Never set both isSaveLeft and isExact for the same invocation. */
+  assert( isSaveLeft==0 || isExact==0 );
+
+  assert_fts3_nc( p!=0 && *p1!=0 && *p2!=0 );
+  if( *p1==POS_COLUMN ){
+    p1++;
+    p1 += fts3GetVarint32(p1, &iCol1);
+    /* iCol1==0 indicates corruption. Column 0 does not have a POS_COLUMN
+    ** entry, so this is actually end-of-doclist. */
+    if( iCol1==0 ) return 0;
+  }
+  if( *p2==POS_COLUMN ){
+    p2++;
+    p2 += fts3GetVarint32(p2, &iCol2);
+    /* As above, iCol2==0 indicates corruption. */
+    if( iCol2==0 ) return 0;
+  }
+
+  while( 1 ){
+    if( iCol1==iCol2 ){
+      char *pSave = p;
+      sqlite3_int64 iPrev = 0;
+      sqlite3_int64 iPos1 = 0;
+      sqlite3_int64 iPos2 = 0;
+
+      if( iCol1 ){
+        *p++ = POS_COLUMN;
+        p += sqlite3Fts3PutVarint(p, iCol1);
+      }
+
+      fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
+      fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
+      if( iPos1<0 || iPos2<0 ) break;
+
+      while( 1 ){
+        if( iPos2==iPos1+nToken
+         || (isExact==0 && iPos2>iPos1 && iPos2<=iPos1+nToken)
+        ){
+          sqlite3_int64 iSave;
+          iSave = isSaveLeft ? iPos1 : iPos2;
+          fts3PutDeltaVarint(&p, &iPrev, iSave+2); iPrev -= 2;
+          pSave = 0;
+          assert( p );
+        }
+        if( (!isSaveLeft && iPos2<=(iPos1+nToken)) || iPos2<=iPos1 ){
+          if( (*p2&0xFE)==0 ) break;
+          fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
+        }else{
+          if( (*p1&0xFE)==0 ) break;
+          fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
+        }
+      }
+
+      if( pSave ){
+        assert( pp && p );
+        p = pSave;
+      }
+
+      fts3ColumnlistCopy(0, &p1);
+      fts3ColumnlistCopy(0, &p2);
+      assert( (*p1&0xFE)==0 && (*p2&0xFE)==0 );
+      if( 0==*p1 || 0==*p2 ) break;
+
+      p1++;
+      p1 += fts3GetVarint32(p1, &iCol1);
+      p2++;
+      p2 += fts3GetVarint32(p2, &iCol2);
+    }
+
+    /* Advance pointer p1 or p2 (whichever corresponds to the smaller of
+    ** iCol1 and iCol2) so that it points to either the 0x00 that marks the
+    ** end of the position list, or the 0x01 that precedes the next
+    ** column-number in the position list.
+    */
+    else if( iCol1<iCol2 ){
+      fts3ColumnlistCopy(0, &p1);
+      if( 0==*p1 ) break;
+      p1++;
+      p1 += fts3GetVarint32(p1, &iCol1);
+    }else{
+      fts3ColumnlistCopy(0, &p2);
+      if( 0==*p2 ) break;
+      p2++;
+      p2 += fts3GetVarint32(p2, &iCol2);
+    }
+  }
+
+  fts3PoslistCopy(0, &p2);
+  fts3PoslistCopy(0, &p1);
+  *pp1 = p1;
+  *pp2 = p2;
+  if( *pp==p ){
+    return 0;
+  }
+  *p++ = 0x00;
+  *pp = p;
+  return 1;
+}
+
+/*
+** Merge two position-lists as required by the NEAR operator. The argument
+** position lists correspond to the left and right phrases of an expression
+** like:
+**
+**     "phrase 1" NEAR "phrase number 2"
+**
+** Position list *pp1 corresponds to the left-hand side of the NEAR
+** expression and *pp2 to the right. As usual, the indexes in the position
+** lists are the offsets of the last token in each phrase (tokens "1" and "2"
+** in the example above).
+**
+** The output position list - written to *pp - is a copy of *pp2 with those
+** entries that are not sufficiently NEAR entries in *pp1 removed.
+*/
+static int fts3PoslistNearMerge(
+  char **pp,                      /* Output buffer */
+  char *aTmp,                     /* Temporary buffer space */
+  int nRight,                     /* Maximum difference in token positions */
+  int nLeft,                      /* Maximum difference in token positions */
+  char **pp1,                     /* IN/OUT: Left input list */
+  char **pp2                      /* IN/OUT: Right input list */
+){
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+
+  char *pTmp1 = aTmp;
+  char *pTmp2;
+  char *aTmp2;
+  int res = 1;
+
+  fts3PoslistPhraseMerge(&pTmp1, nRight, 0, 0, pp1, pp2);
+  aTmp2 = pTmp2 = pTmp1;
+  *pp1 = p1;
+  *pp2 = p2;
+  fts3PoslistPhraseMerge(&pTmp2, nLeft, 1, 0, pp2, pp1);
+  if( pTmp1!=aTmp && pTmp2!=aTmp2 ){
+    fts3PoslistMerge(pp, &aTmp, &aTmp2);
+  }else if( pTmp1!=aTmp ){
+    fts3PoslistCopy(pp, &aTmp);
+  }else if( pTmp2!=aTmp2 ){
+    fts3PoslistCopy(pp, &aTmp2);
+  }else{
+    res = 0;
+  }
+
+  return res;
+}
+
+/*
+** An instance of this function is used to merge together the (potentially
+** large number of) doclists for each term that matches a prefix query.
+** See function fts3TermSelectMerge() for details.
+*/
+typedef struct TermSelect TermSelect;
+struct TermSelect {
+  char *aaOutput[16];             /* Malloc'd output buffers */
+  int anOutput[16];               /* Size each output buffer in bytes */
+};
+
+/*
+** This function is used to read a single varint from a buffer. Parameter
+** pEnd points 1 byte past the end of the buffer. When this function is
+** called, if *pp points to pEnd or greater, then the end of the buffer
+** has been reached. In this case *pp is set to 0 and the function returns.
+**
+** If *pp does not point to or past pEnd, then a single varint is read
+** from *pp. *pp is then set to point 1 byte past the end of the read varint.
+**
+** If bDescIdx is false, the value read is added to *pVal before returning.
+** If it is true, the value read is subtracted from *pVal before this
+** function returns.
+*/
+static void fts3GetDeltaVarint3(
+  char **pp,                      /* IN/OUT: Point to read varint from */
+  char *pEnd,                     /* End of buffer */
+  int bDescIdx,                   /* True if docids are descending */
+  sqlite3_int64 *pVal             /* IN/OUT: Integer value */
+){
+  if( *pp>=pEnd ){
+    *pp = 0;
+  }else{
+    u64 iVal;
+    *pp += sqlite3Fts3GetVarintU(*pp, &iVal);
+    if( bDescIdx ){
+      *pVal = (i64)((u64)*pVal - iVal);
+    }else{
+      *pVal = (i64)((u64)*pVal + iVal);
+    }
+  }
+}
+
+/*
+** This function is used to write a single varint to a buffer. The varint
+** is written to *pp. Before returning, *pp is set to point 1 byte past the
+** end of the value written.
+**
+** If *pbFirst is zero when this function is called, the value written to
+** the buffer is that of parameter iVal.
+**
+** If *pbFirst is non-zero when this function is called, then the value
+** written is either (iVal-*piPrev) (if bDescIdx is zero) or (*piPrev-iVal)
+** (if bDescIdx is non-zero).
+**
+** Before returning, this function always sets *pbFirst to 1 and *piPrev
+** to the value of parameter iVal.
+*/
+static void fts3PutDeltaVarint3(
+  char **pp,                      /* IN/OUT: Output pointer */
+  int bDescIdx,                   /* True for descending docids */
+  sqlite3_int64 *piPrev,          /* IN/OUT: Previous value written to list */
+  int *pbFirst,                   /* IN/OUT: True after first int written */
+  sqlite3_int64 iVal              /* Write this value to the list */
+){
+  sqlite3_uint64 iWrite;
+  if( bDescIdx==0 || *pbFirst==0 ){
+    assert_fts3_nc( *pbFirst==0 || iVal>=*piPrev );
+    iWrite = (u64)iVal - (u64)*piPrev;
+  }else{
+    assert_fts3_nc( *piPrev>=iVal );
+    iWrite = (u64)*piPrev - (u64)iVal;
+  }
+  assert( *pbFirst || *piPrev==0 );
+  assert_fts3_nc( *pbFirst==0 || iWrite>0 );
+  *pp += sqlite3Fts3PutVarint(*pp, iWrite);
+  *piPrev = iVal;
+  *pbFirst = 1;
+}
+
+
+/*
+** This macro is used by various functions that merge doclists. The two
+** arguments are 64-bit docid values. If the value of the stack variable
+** bDescDoclist is 0 when this macro is invoked, then it returns (i1-i2).
+** Otherwise, (i2-i1).
+**
+** Using this makes it easier to write code that can merge doclists that are
+** sorted in either ascending or descending order.
+*/
+/* #define DOCID_CMP(i1, i2) ((bDescDoclist?-1:1) * (i64)((u64)i1-i2)) */
+#define DOCID_CMP(i1, i2) ((bDescDoclist?-1:1) * (i1>i2?1:((i1==i2)?0:-1)))
+
+/*
+** This function does an "OR" merge of two doclists (output contains all
+** positions contained in either argument doclist). If the docids in the
+** input doclists are sorted in ascending order, parameter bDescDoclist
+** should be false. If they are sorted in ascending order, it should be
+** passed a non-zero value.
+**
+** If no error occurs, *paOut is set to point at an sqlite3_malloc'd buffer
+** containing the output doclist and SQLITE_OK is returned. In this case
+** *pnOut is set to the number of bytes in the output doclist.
+**
+** If an error occurs, an SQLite error code is returned. The output values
+** are undefined in this case.
+*/
+static int fts3DoclistOrMerge(
+  int bDescDoclist,               /* True if arguments are desc */
+  char *a1, int n1,               /* First doclist */
+  char *a2, int n2,               /* Second doclist */
+  char **paOut, int *pnOut        /* OUT: Malloc'd doclist */
+){
+  int rc = SQLITE_OK;
+  sqlite3_int64 i1 = 0;
+  sqlite3_int64 i2 = 0;
+  sqlite3_int64 iPrev = 0;
+  char *pEnd1 = &a1[n1];
+  char *pEnd2 = &a2[n2];
+  char *p1 = a1;
+  char *p2 = a2;
+  char *p;
+  char *aOut;
+  int bFirstOut = 0;
+
+  *paOut = 0;
+  *pnOut = 0;
+
+  /* Allocate space for the output. Both the input and output doclists
+  ** are delta encoded. If they are in ascending order (bDescDoclist==0),
+  ** then the first docid in each list is simply encoded as a varint. For
+  ** each subsequent docid, the varint stored is the difference between the
+  ** current and previous docid (a positive number - since the list is in
+  ** ascending order).
+  **
+  ** The first docid written to the output is therefore encoded using the
+  ** same number of bytes as it is in whichever of the input lists it is
+  ** read from. And each subsequent docid read from the same input list
+  ** consumes either the same or less bytes as it did in the input (since
+  ** the difference between it and the previous value in the output must
+  ** be a positive value less than or equal to the delta value read from
+  ** the input list). The same argument applies to all but the first docid
+  ** read from the 'other' list. And to the contents of all position lists
+  ** that will be copied and merged from the input to the output.
+  **
+  ** However, if the first docid copied to the output is a negative number,
+  ** then the encoding of the first docid from the 'other' input list may
+  ** be larger in the output than it was in the input (since the delta value
+  ** may be a larger positive integer than the actual docid).
+  **
+  ** The space required to store the output is therefore the sum of the
+  ** sizes of the two inputs, plus enough space for exactly one of the input
+  ** docids to grow.
+  **
+  ** A symetric argument may be made if the doclists are in descending
+  ** order.
+  */
+  aOut = sqlite3_malloc64((i64)n1+n2+FTS3_VARINT_MAX-1+FTS3_BUFFER_PADDING);
+  if( !aOut ) return SQLITE_NOMEM;
+
+  p = aOut;
+  fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1);
+  fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2);
+  while( p1 || p2 ){
+    sqlite3_int64 iDiff = DOCID_CMP(i1, i2);
+
+    if( p2 && p1 && iDiff==0 ){
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1);
+      rc = fts3PoslistMerge(&p, &p1, &p2);
+      if( rc ) break;
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }else if( !p2 || (p1 && iDiff<0) ){
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1);
+      fts3PoslistCopy(&p, &p1);
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+    }else{
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i2);
+      fts3PoslistCopy(&p, &p2);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }
+
+    assert( (p-aOut)<=((p1?(p1-a1):n1)+(p2?(p2-a2):n2)+FTS3_VARINT_MAX-1) );
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(aOut);
+    p = aOut = 0;
+  }else{
+    assert( (p-aOut)<=n1+n2+FTS3_VARINT_MAX-1 );
+    memset(&aOut[(p-aOut)], 0, FTS3_BUFFER_PADDING);
+  }
+  *paOut = aOut;
+  *pnOut = (int)(p-aOut);
+  return rc;
+}
+
+/*
+** This function does a "phrase" merge of two doclists. In a phrase merge,
+** the output contains a copy of each position from the right-hand input
+** doclist for which there is a position in the left-hand input doclist
+** exactly nDist tokens before it.
+**
+** If the docids in the input doclists are sorted in ascending order,
+** parameter bDescDoclist should be false. If they are sorted in ascending
+** order, it should be passed a non-zero value.
+**
+** The right-hand input doclist is overwritten by this function.
+*/
+static int fts3DoclistPhraseMerge(
+  int bDescDoclist,               /* True if arguments are desc */
+  int nDist,                      /* Distance from left to right (1=adjacent) */
+  char *aLeft, int nLeft,         /* Left doclist */
+  char **paRight, int *pnRight    /* IN/OUT: Right/output doclist */
+){
+  sqlite3_int64 i1 = 0;
+  sqlite3_int64 i2 = 0;
+  sqlite3_int64 iPrev = 0;
+  char *aRight = *paRight;
+  char *pEnd1 = &aLeft[nLeft];
+  char *pEnd2 = &aRight[*pnRight];
+  char *p1 = aLeft;
+  char *p2 = aRight;
+  char *p;
+  int bFirstOut = 0;
+  char *aOut;
+
+  assert( nDist>0 );
+  if( bDescDoclist ){
+    aOut = sqlite3_malloc64((sqlite3_int64)*pnRight + FTS3_VARINT_MAX);
+    if( aOut==0 ) return SQLITE_NOMEM;
+  }else{
+    aOut = aRight;
+  }
+  p = aOut;
+
+  fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1);
+  fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2);
+
+  while( p1 && p2 ){
+    sqlite3_int64 iDiff = DOCID_CMP(i1, i2);
+    if( iDiff==0 ){
+      char *pSave = p;
+      sqlite3_int64 iPrevSave = iPrev;
+      int bFirstOutSave = bFirstOut;
+
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1);
+      if( 0==fts3PoslistPhraseMerge(&p, nDist, 0, 1, &p1, &p2) ){
+        p = pSave;
+        iPrev = iPrevSave;
+        bFirstOut = bFirstOutSave;
+      }
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }else if( iDiff<0 ){
+      fts3PoslistCopy(0, &p1);
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+    }else{
+      fts3PoslistCopy(0, &p2);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }
+  }
+
+  *pnRight = (int)(p - aOut);
+  if( bDescDoclist ){
+    sqlite3_free(aRight);
+    *paRight = aOut;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Argument pList points to a position list nList bytes in size. This
+** function checks to see if the position list contains any entries for
+** a token in position 0 (of any column). If so, it writes argument iDelta
+** to the output buffer pOut, followed by a position list consisting only
+** of the entries from pList at position 0, and terminated by an 0x00 byte.
+** The value returned is the number of bytes written to pOut (if any).
+*/
+SQLITE_PRIVATE int sqlite3Fts3FirstFilter(
+  sqlite3_int64 iDelta,           /* Varint that may be written to pOut */
+  char *pList,                    /* Position list (no 0x00 term) */
+  int nList,                      /* Size of pList in bytes */
+  char *pOut                      /* Write output here */
+){
+  int nOut = 0;
+  int bWritten = 0;               /* True once iDelta has been written */
+  char *p = pList;
+  char *pEnd = &pList[nList];
+
+  if( *p!=0x01 ){
+    if( *p==0x02 ){
+      nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta);
+      pOut[nOut++] = 0x02;
+      bWritten = 1;
+    }
+    fts3ColumnlistCopy(0, &p);
+  }
+
+  while( p<pEnd ){
+    sqlite3_int64 iCol;
+    p++;
+    p += sqlite3Fts3GetVarint(p, &iCol);
+    if( *p==0x02 ){
+      if( bWritten==0 ){
+        nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta);
+        bWritten = 1;
+      }
+      pOut[nOut++] = 0x01;
+      nOut += sqlite3Fts3PutVarint(&pOut[nOut], iCol);
+      pOut[nOut++] = 0x02;
+    }
+    fts3ColumnlistCopy(0, &p);
+  }
+  if( bWritten ){
+    pOut[nOut++] = 0x00;
+  }
+
+  return nOut;
+}
+
+
+/*
+** Merge all doclists in the TermSelect.aaOutput[] array into a single
+** doclist stored in TermSelect.aaOutput[0]. If successful, delete all
+** other doclists (except the aaOutput[0] one) and return SQLITE_OK.
+**
+** If an OOM error occurs, return SQLITE_NOMEM. In this case it is
+** the responsibility of the caller to free any doclists left in the
+** TermSelect.aaOutput[] array.
+*/
+static int fts3TermSelectFinishMerge(Fts3Table *p, TermSelect *pTS){
+  char *aOut = 0;
+  int nOut = 0;
+  int i;
+
+  /* Loop through the doclists in the aaOutput[] array. Merge them all
+  ** into a single doclist.
+  */
+  for(i=0; i<SizeofArray(pTS->aaOutput); i++){
+    if( pTS->aaOutput[i] ){
+      if( !aOut ){
+        aOut = pTS->aaOutput[i];
+        nOut = pTS->anOutput[i];
+        pTS->aaOutput[i] = 0;
+      }else{
+        int nNew;
+        char *aNew;
+
+        int rc = fts3DoclistOrMerge(p->bDescIdx,
+            pTS->aaOutput[i], pTS->anOutput[i], aOut, nOut, &aNew, &nNew
+        );
+        if( rc!=SQLITE_OK ){
+          sqlite3_free(aOut);
+          return rc;
+        }
+
+        sqlite3_free(pTS->aaOutput[i]);
+        sqlite3_free(aOut);
+        pTS->aaOutput[i] = 0;
+        aOut = aNew;
+        nOut = nNew;
+      }
+    }
+  }
+
+  pTS->aaOutput[0] = aOut;
+  pTS->anOutput[0] = nOut;
+  return SQLITE_OK;
+}
+
+/*
+** Merge the doclist aDoclist/nDoclist into the TermSelect object passed
+** as the first argument. The merge is an "OR" merge (see function
+** fts3DoclistOrMerge() for details).
+**
+** This function is called with the doclist for each term that matches
+** a queried prefix. It merges all these doclists into one, the doclist
+** for the specified prefix. Since there can be a very large number of
+** doclists to merge, the merging is done pair-wise using the TermSelect
+** object.
+**
+** This function returns SQLITE_OK if the merge is successful, or an
+** SQLite error code (SQLITE_NOMEM) if an error occurs.
+*/
+static int fts3TermSelectMerge(
+  Fts3Table *p,                   /* FTS table handle */
+  TermSelect *pTS,                /* TermSelect object to merge into */
+  char *aDoclist,                 /* Pointer to doclist */
+  int nDoclist                    /* Size of aDoclist in bytes */
+){
+  if( pTS->aaOutput[0]==0 ){
+    /* If this is the first term selected, copy the doclist to the output
+    ** buffer using memcpy().
+    **
+    ** Add FTS3_VARINT_MAX bytes of unused space to the end of the
+    ** allocation. This is so as to ensure that the buffer is big enough
+    ** to hold the current doclist AND'd with any other doclist. If the
+    ** doclists are stored in order=ASC order, this padding would not be
+    ** required (since the size of [doclistA AND doclistB] is always less
+    ** than or equal to the size of [doclistA] in that case). But this is
+    ** not true for order=DESC. For example, a doclist containing (1, -1)
+    ** may be smaller than (-1), as in the first example the -1 may be stored
+    ** as a single-byte delta, whereas in the second it must be stored as a
+    ** FTS3_VARINT_MAX byte varint.
+    **
+    ** Similar padding is added in the fts3DoclistOrMerge() function.
+    */
+    pTS->aaOutput[0] = sqlite3_malloc64((i64)nDoclist + FTS3_VARINT_MAX + 1);
+    pTS->anOutput[0] = nDoclist;
+    if( pTS->aaOutput[0] ){
+      memcpy(pTS->aaOutput[0], aDoclist, nDoclist);
+      memset(&pTS->aaOutput[0][nDoclist], 0, FTS3_VARINT_MAX);
+    }else{
+      return SQLITE_NOMEM;
+    }
+  }else{
+    char *aMerge = aDoclist;
+    int nMerge = nDoclist;
+    int iOut;
+
+    for(iOut=0; iOut<SizeofArray(pTS->aaOutput); iOut++){
+      if( pTS->aaOutput[iOut]==0 ){
+        assert( iOut>0 );
+        pTS->aaOutput[iOut] = aMerge;
+        pTS->anOutput[iOut] = nMerge;
+        break;
+      }else{
+        char *aNew;
+        int nNew;
+
+        int rc = fts3DoclistOrMerge(p->bDescIdx, aMerge, nMerge,
+            pTS->aaOutput[iOut], pTS->anOutput[iOut], &aNew, &nNew
+        );
+        if( rc!=SQLITE_OK ){
+          if( aMerge!=aDoclist ) sqlite3_free(aMerge);
+          return rc;
+        }
+
+        if( aMerge!=aDoclist ) sqlite3_free(aMerge);
+        sqlite3_free(pTS->aaOutput[iOut]);
+        pTS->aaOutput[iOut] = 0;
+
+        aMerge = aNew;
+        nMerge = nNew;
+        if( (iOut+1)==SizeofArray(pTS->aaOutput) ){
+          pTS->aaOutput[iOut] = aMerge;
+          pTS->anOutput[iOut] = nMerge;
+        }
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Append SegReader object pNew to the end of the pCsr->apSegment[] array.
+*/
+static int fts3SegReaderCursorAppend(
+  Fts3MultiSegReader *pCsr,
+  Fts3SegReader *pNew
+){
+  if( (pCsr->nSegment%16)==0 ){
+    Fts3SegReader **apNew;
+    sqlite3_int64 nByte = (pCsr->nSegment + 16)*sizeof(Fts3SegReader*);
+    apNew = (Fts3SegReader **)sqlite3_realloc64(pCsr->apSegment, nByte);
+    if( !apNew ){
+      sqlite3Fts3SegReaderFree(pNew);
+      return SQLITE_NOMEM;
+    }
+    pCsr->apSegment = apNew;
+  }
+  pCsr->apSegment[pCsr->nSegment++] = pNew;
+  return SQLITE_OK;
+}
+
+/*
+** Add seg-reader objects to the Fts3MultiSegReader object passed as the
+** 8th argument.
+**
+** This function returns SQLITE_OK if successful, or an SQLite error code
+** otherwise.
+*/
+static int fts3SegReaderCursor(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index to search (from 0 to p->nIndex-1) */
+  int iLevel,                     /* Level of segments to scan */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  int isScan,                     /* True to scan from zTerm to EOF */
+  Fts3MultiSegReader *pCsr        /* Cursor object to populate */
+){
+  int rc = SQLITE_OK;             /* Error code */
+  sqlite3_stmt *pStmt = 0;        /* Statement to iterate through segments */
+  int rc2;                        /* Result of sqlite3_reset() */
+
+  /* If iLevel is less than 0 and this is not a scan, include a seg-reader
+  ** for the pending-terms. If this is a scan, then this call must be being
+  ** made by an fts4aux module, not an FTS table. In this case calling
+  ** Fts3SegReaderPending might segfault, as the data structures used by
+  ** fts4aux are not completely populated. So it's easiest to filter these
+  ** calls out here.  */
+  if( iLevel<0 && p->aIndex && p->iPrevLangid==iLangid ){
+    Fts3SegReader *pSeg = 0;
+    rc = sqlite3Fts3SegReaderPending(p, iIndex, zTerm, nTerm, isPrefix||isScan, &pSeg);
+    if( rc==SQLITE_OK && pSeg ){
+      rc = fts3SegReaderCursorAppend(pCsr, pSeg);
+    }
+  }
+
+  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts3AllSegdirs(p, iLangid, iIndex, iLevel, &pStmt);
+    }
+
+    while( rc==SQLITE_OK && SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
+      Fts3SegReader *pSeg = 0;
+
+      /* Read the values returned by the SELECT into local variables. */
+      sqlite3_int64 iStartBlock = sqlite3_column_int64(pStmt, 1);
+      sqlite3_int64 iLeavesEndBlock = sqlite3_column_int64(pStmt, 2);
+      sqlite3_int64 iEndBlock = sqlite3_column_int64(pStmt, 3);
+      int nRoot = sqlite3_column_bytes(pStmt, 4);
+      char const *zRoot = sqlite3_column_blob(pStmt, 4);
+
+      /* If zTerm is not NULL, and this segment is not stored entirely on its
+      ** root node, the range of leaves scanned can be reduced. Do this. */
+      if( iStartBlock && zTerm && zRoot ){
+        sqlite3_int64 *pi = (isPrefix ? &iLeavesEndBlock : 0);
+        rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &iStartBlock, pi);
+        if( rc!=SQLITE_OK ) goto finished;
+        if( isPrefix==0 && isScan==0 ) iLeavesEndBlock = iStartBlock;
+      }
+
+      rc = sqlite3Fts3SegReaderNew(pCsr->nSegment+1,
+          (isPrefix==0 && isScan==0),
+          iStartBlock, iLeavesEndBlock,
+          iEndBlock, zRoot, nRoot, &pSeg
+      );
+      if( rc!=SQLITE_OK ) goto finished;
+      rc = fts3SegReaderCursorAppend(pCsr, pSeg);
+    }
+  }
+
+ finished:
+  rc2 = sqlite3_reset(pStmt);
+  if( rc==SQLITE_DONE ) rc = rc2;
+
+  return rc;
+}
+
+/*
+** Set up a cursor object for iterating through a full-text index or a
+** single level therein.
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderCursor(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language-id to search */
+  int iIndex,                     /* Index to search (from 0 to p->nIndex-1) */
+  int iLevel,                     /* Level of segments to scan */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  int isScan,                     /* True to scan from zTerm to EOF */
+  Fts3MultiSegReader *pCsr       /* Cursor object to populate */
+){
+  assert( iIndex>=0 && iIndex<p->nIndex );
+  assert( iLevel==FTS3_SEGCURSOR_ALL
+      ||  iLevel==FTS3_SEGCURSOR_PENDING
+      ||  iLevel>=0
+  );
+  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
+  assert( FTS3_SEGCURSOR_ALL<0 && FTS3_SEGCURSOR_PENDING<0 );
+  assert( isPrefix==0 || isScan==0 );
+
+  memset(pCsr, 0, sizeof(Fts3MultiSegReader));
+  return fts3SegReaderCursor(
+      p, iLangid, iIndex, iLevel, zTerm, nTerm, isPrefix, isScan, pCsr
+  );
+}
+
+/*
+** In addition to its current configuration, have the Fts3MultiSegReader
+** passed as the 4th argument also scan the doclist for term zTerm/nTerm.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3SegReaderCursorAddZero(
+  Fts3Table *p,                   /* FTS virtual table handle */
+  int iLangid,
+  const char *zTerm,              /* Term to scan doclist of */
+  int nTerm,                      /* Number of bytes in zTerm */
+  Fts3MultiSegReader *pCsr        /* Fts3MultiSegReader to modify */
+){
+  return fts3SegReaderCursor(p,
+      iLangid, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0,pCsr
+  );
+}
+
+/*
+** Open an Fts3MultiSegReader to scan the doclist for term zTerm/nTerm. Or,
+** if isPrefix is true, to scan the doclist for all terms for which
+** zTerm/nTerm is a prefix. If successful, return SQLITE_OK and write
+** a pointer to the new Fts3MultiSegReader to *ppSegcsr. Otherwise, return
+** an SQLite error code.
+**
+** It is the responsibility of the caller to free this object by eventually
+** passing it to fts3SegReaderCursorFree()
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+** Output parameter *ppSegcsr is set to 0 if an error occurs.
+*/
+static int fts3TermSegReaderCursor(
+  Fts3Cursor *pCsr,               /* Virtual table cursor handle */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  Fts3MultiSegReader **ppSegcsr   /* OUT: Allocated seg-reader cursor */
+){
+  Fts3MultiSegReader *pSegcsr;    /* Object to allocate and return */
+  int rc = SQLITE_NOMEM;          /* Return code */
+
+  pSegcsr = sqlite3_malloc(sizeof(Fts3MultiSegReader));
+  if( pSegcsr ){
+    int i;
+    int bFound = 0;               /* True once an index has been found */
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+
+    if( isPrefix ){
+      for(i=1; bFound==0 && i<p->nIndex; i++){
+        if( p->aIndex[i].nPrefix==nTerm ){
+          bFound = 1;
+          rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid,
+              i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0, pSegcsr
+          );
+          pSegcsr->bLookup = 1;
+        }
+      }
+
+      for(i=1; bFound==0 && i<p->nIndex; i++){
+        if( p->aIndex[i].nPrefix==nTerm+1 ){
+          bFound = 1;
+          rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid,
+              i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 1, 0, pSegcsr
+          );
+          if( rc==SQLITE_OK ){
+            rc = fts3SegReaderCursorAddZero(
+                p, pCsr->iLangid, zTerm, nTerm, pSegcsr
+            );
+          }
+        }
+      }
+    }
+
+    if( bFound==0 ){
+      rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid,
+          0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, isPrefix, 0, pSegcsr
+      );
+      pSegcsr->bLookup = !isPrefix;
+    }
+  }
+
+  *ppSegcsr = pSegcsr;
+  return rc;
+}
+
+/*
+** Free an Fts3MultiSegReader allocated by fts3TermSegReaderCursor().
+*/
+static void fts3SegReaderCursorFree(Fts3MultiSegReader *pSegcsr){
+  sqlite3Fts3SegReaderFinish(pSegcsr);
+  sqlite3_free(pSegcsr);
+}
+
+/*
+** This function retrieves the doclist for the specified term (or term
+** prefix) from the database.
+*/
+static int fts3TermSelect(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3PhraseToken *pTok,          /* Token to query for */
+  int iColumn,                    /* Column to query (or -ve for all columns) */
+  int *pnOut,                     /* OUT: Size of buffer at *ppOut */
+  char **ppOut                    /* OUT: Malloced result buffer */
+){
+  int rc;                         /* Return code */
+  Fts3MultiSegReader *pSegcsr;    /* Seg-reader cursor for this term */
+  TermSelect tsc;                 /* Object for pair-wise doclist merging */
+  Fts3SegFilter filter;           /* Segment term filter configuration */
+
+  pSegcsr = pTok->pSegcsr;
+  memset(&tsc, 0, sizeof(TermSelect));
+
+  filter.flags = FTS3_SEGMENT_IGNORE_EMPTY | FTS3_SEGMENT_REQUIRE_POS
+        | (pTok->isPrefix ? FTS3_SEGMENT_PREFIX : 0)
+        | (pTok->bFirst ? FTS3_SEGMENT_FIRST : 0)
+        | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0);
+  filter.iCol = iColumn;
+  filter.zTerm = pTok->z;
+  filter.nTerm = pTok->n;
+
+  rc = sqlite3Fts3SegReaderStart(p, pSegcsr, &filter);
+  while( SQLITE_OK==rc
+      && SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, pSegcsr))
+  ){
+    rc = fts3TermSelectMerge(p, &tsc, pSegcsr->aDoclist, pSegcsr->nDoclist);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts3TermSelectFinishMerge(p, &tsc);
+  }
+  if( rc==SQLITE_OK ){
+    *ppOut = tsc.aaOutput[0];
+    *pnOut = tsc.anOutput[0];
+  }else{
+    int i;
+    for(i=0; i<SizeofArray(tsc.aaOutput); i++){
+      sqlite3_free(tsc.aaOutput[i]);
+    }
+  }
+
+  fts3SegReaderCursorFree(pSegcsr);
+  pTok->pSegcsr = 0;
+  return rc;
+}
+
+/*
+** This function counts the total number of docids in the doclist stored
+** in buffer aList[], size nList bytes.
+**
+** If the isPoslist argument is true, then it is assumed that the doclist
+** contains a position-list following each docid. Otherwise, it is assumed
+** that the doclist is simply a list of docids stored as delta encoded
+** varints.
+*/
+static int fts3DoclistCountDocids(char *aList, int nList){
+  int nDoc = 0;                   /* Return value */
+  if( aList ){
+    char *aEnd = &aList[nList];   /* Pointer to one byte after EOF */
+    char *p = aList;              /* Cursor */
+    while( p<aEnd ){
+      nDoc++;
+      while( (*p++)&0x80 );     /* Skip docid varint */
+      fts3PoslistCopy(0, &p);   /* Skip over position list */
+    }
+  }
+
+  return nDoc;
+}
+
+/*
+** Advance the cursor to the next row in the %_content table that
+** matches the search criteria.  For a MATCH search, this will be
+** the next row that matches. For a full-table scan, this will be
+** simply the next row in the %_content table.  For a docid lookup,
+** this routine simply sets the EOF flag.
+**
+** Return SQLITE_OK if nothing goes wrong.  SQLITE_OK is returned
+** even if we reach end-of-file.  The fts3EofMethod() will be called
+** subsequently to determine whether or not an EOF was hit.
+*/
+static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){
+  int rc;
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+  if( pCsr->eSearch==FTS3_DOCID_SEARCH || pCsr->eSearch==FTS3_FULLSCAN_SEARCH ){
+    Fts3Table *pTab = (Fts3Table*)pCursor->pVtab;
+    pTab->bLock++;
+    if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){
+      pCsr->isEof = 1;
+      rc = sqlite3_reset(pCsr->pStmt);
+    }else{
+      pCsr->iPrevId = sqlite3_column_int64(pCsr->pStmt, 0);
+      rc = SQLITE_OK;
+    }
+    pTab->bLock--;
+  }else{
+    rc = fts3EvalNext((Fts3Cursor *)pCursor);
+  }
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  return rc;
+}
+
+/*
+** If the numeric type of argument pVal is "integer", then return it
+** converted to a 64-bit signed integer. Otherwise, return a copy of
+** the second parameter, iDefault.
+*/
+static sqlite3_int64 fts3DocidRange(sqlite3_value *pVal, i64 iDefault){
+  if( pVal ){
+    int eType = sqlite3_value_numeric_type(pVal);
+    if( eType==SQLITE_INTEGER ){
+      return sqlite3_value_int64(pVal);
+    }
+  }
+  return iDefault;
+}
+
+/*
+** This is the xFilter interface for the virtual table.  See
+** the virtual table xFilter method documentation for additional
+** information.
+**
+** If idxNum==FTS3_FULLSCAN_SEARCH then do a full table scan against
+** the %_content table.
+**
+** If idxNum==FTS3_DOCID_SEARCH then do a docid lookup for a single entry
+** in the %_content table.
+**
+** If idxNum>=FTS3_FULLTEXT_SEARCH then use the full text index.  The
+** column on the left-hand side of the MATCH operator is column
+** number idxNum-FTS3_FULLTEXT_SEARCH, 0 indexed.  argv[0] is the right-hand
+** side of the MATCH operator.
+*/
+static int fts3FilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  int rc = SQLITE_OK;
+  char *zSql;                     /* SQL statement used to access %_content */
+  int eSearch;
+  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+
+  sqlite3_value *pCons = 0;       /* The MATCH or rowid constraint, if any */
+  sqlite3_value *pLangid = 0;     /* The "langid = ?" constraint, if any */
+  sqlite3_value *pDocidGe = 0;    /* The "docid >= ?" constraint, if any */
+  sqlite3_value *pDocidLe = 0;    /* The "docid <= ?" constraint, if any */
+  int iIdx;
+
+  UNUSED_PARAMETER(idxStr);
+  UNUSED_PARAMETER(nVal);
+
+  if( p->bLock ){
+    return SQLITE_ERROR;
+  }
+
+  eSearch = (idxNum & 0x0000FFFF);
+  assert( eSearch>=0 && eSearch<=(FTS3_FULLTEXT_SEARCH+p->nColumn) );
+  assert( p->pSegments==0 );
+
+  /* Collect arguments into local variables */
+  iIdx = 0;
+  if( eSearch!=FTS3_FULLSCAN_SEARCH ) pCons = apVal[iIdx++];
+  if( idxNum & FTS3_HAVE_LANGID ) pLangid = apVal[iIdx++];
+  if( idxNum & FTS3_HAVE_DOCID_GE ) pDocidGe = apVal[iIdx++];
+  if( idxNum & FTS3_HAVE_DOCID_LE ) pDocidLe = apVal[iIdx++];
+  assert( iIdx==nVal );
+
+  /* In case the cursor has been used before, clear it now. */
+  fts3ClearCursor(pCsr);
+
+  /* Set the lower and upper bounds on docids to return */
+  pCsr->iMinDocid = fts3DocidRange(pDocidGe, SMALLEST_INT64);
+  pCsr->iMaxDocid = fts3DocidRange(pDocidLe, LARGEST_INT64);
+
+  if( idxStr ){
+    pCsr->bDesc = (idxStr[0]=='D');
+  }else{
+    pCsr->bDesc = p->bDescIdx;
+  }
+  pCsr->eSearch = (i16)eSearch;
+
+  if( eSearch!=FTS3_DOCID_SEARCH && eSearch!=FTS3_FULLSCAN_SEARCH ){
+    int iCol = eSearch-FTS3_FULLTEXT_SEARCH;
+    const char *zQuery = (const char *)sqlite3_value_text(pCons);
+
+    if( zQuery==0 && sqlite3_value_type(pCons)!=SQLITE_NULL ){
+      return SQLITE_NOMEM;
+    }
+
+    pCsr->iLangid = 0;
+    if( pLangid ) pCsr->iLangid = sqlite3_value_int(pLangid);
+
+    assert( p->base.zErrMsg==0 );
+    rc = sqlite3Fts3ExprParse(p->pTokenizer, pCsr->iLangid,
+        p->azColumn, p->bFts4, p->nColumn, iCol, zQuery, -1, &pCsr->pExpr,
+        &p->base.zErrMsg
+    );
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    rc = fts3EvalStart(pCsr);
+    sqlite3Fts3SegmentsClose(p);
+    if( rc!=SQLITE_OK ) return rc;
+    pCsr->pNextId = pCsr->aDoclist;
+    pCsr->iPrevId = 0;
+  }
+
+  /* Compile a SELECT statement for this cursor. For a full-table-scan, the
+  ** statement loops through all rows of the %_content table. For a
+  ** full-text query or docid lookup, the statement retrieves a single
+  ** row by docid.
+  */
+  if( eSearch==FTS3_FULLSCAN_SEARCH ){
+    if( pDocidGe || pDocidLe ){
+      zSql = sqlite3_mprintf(
+          "SELECT %s WHERE rowid BETWEEN %lld AND %lld ORDER BY rowid %s",
+          p->zReadExprlist, pCsr->iMinDocid, pCsr->iMaxDocid,
+          (pCsr->bDesc ? "DESC" : "ASC")
+      );
+    }else{
+      zSql = sqlite3_mprintf("SELECT %s ORDER BY rowid %s",
+          p->zReadExprlist, (pCsr->bDesc ? "DESC" : "ASC")
+      );
+    }
+    if( zSql ){
+      p->bLock++;
+      rc = sqlite3_prepare_v3(
+          p->db,zSql,-1,SQLITE_PREPARE_PERSISTENT,&pCsr->pStmt,0
+      );
+      p->bLock--;
+      sqlite3_free(zSql);
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }else if( eSearch==FTS3_DOCID_SEARCH ){
+    rc = fts3CursorSeekStmt(pCsr);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_bind_value(pCsr->pStmt, 1, pCons);
+    }
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  return fts3NextMethod(pCursor);
+}
+
+/*
+** This is the xEof method of the virtual table. SQLite calls this
+** routine to find out if it has reached the end of a result set.
+*/
+static int fts3EofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3Cursor *pCsr = (Fts3Cursor*)pCursor;
+  if( pCsr->isEof ){
+    fts3ClearCursor(pCsr);
+    pCsr->isEof = 1;
+  }
+  return pCsr->isEof;
+}
+
+/*
+** This is the xRowid method. The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set. fts3
+** exposes %_content.docid as the rowid for the virtual table. The
+** rowid should be written to *pRowid.
+*/
+static int fts3RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
+  *pRowid = pCsr->iPrevId;
+  return SQLITE_OK;
+}
+
+/*
+** This is the xColumn method, called by SQLite to request a value from
+** the row that the supplied cursor currently points to.
+**
+** If:
+**
+**   (iCol <  p->nColumn)   -> The value of the iCol'th user column.
+**   (iCol == p->nColumn)   -> Magic column with the same name as the table.
+**   (iCol == p->nColumn+1) -> Docid column
+**   (iCol == p->nColumn+2) -> Langid column
+*/
+static int fts3ColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  int rc = SQLITE_OK;             /* Return Code */
+  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
+  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
+
+  /* The column value supplied by SQLite must be in range. */
+  assert( iCol>=0 && iCol<=p->nColumn+2 );
+
+  switch( iCol-p->nColumn ){
+    case 0:
+      /* The special 'table-name' column */
+      sqlite3_result_pointer(pCtx, pCsr, "fts3cursor", 0);
+      break;
+
+    case 1:
+      /* The docid column */
+      sqlite3_result_int64(pCtx, pCsr->iPrevId);
+      break;
+
+    case 2:
+      if( pCsr->pExpr ){
+        sqlite3_result_int64(pCtx, pCsr->iLangid);
+        break;
+      }else if( p->zLanguageid==0 ){
+        sqlite3_result_int(pCtx, 0);
+        break;
+      }else{
+        iCol = p->nColumn;
+        /* no break */ deliberate_fall_through
+      }
+
+    default:
+      /* A user column. Or, if this is a full-table scan, possibly the
+      ** language-id column. Seek the cursor. */
+      rc = fts3CursorSeek(0, pCsr);
+      if( rc==SQLITE_OK && sqlite3_data_count(pCsr->pStmt)-1>iCol ){
+        sqlite3_result_value(pCtx, sqlite3_column_value(pCsr->pStmt, iCol+1));
+      }
+      break;
+  }
+
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  return rc;
+}
+
+/*
+** This function is the implementation of the xUpdate callback used by
+** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
+** inserted, updated or deleted.
+*/
+static int fts3UpdateMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  return sqlite3Fts3UpdateMethod(pVtab, nArg, apVal, pRowid);
+}
+
+/*
+** Implementation of xSync() method. Flush the contents of the pending-terms
+** hash-table to the database.
+*/
+static int fts3SyncMethod(sqlite3_vtab *pVtab){
+
+  /* Following an incremental-merge operation, assuming that the input
+  ** segments are not completely consumed (the usual case), they are updated
+  ** in place to remove the entries that have already been merged. This
+  ** involves updating the leaf block that contains the smallest unmerged
+  ** entry and each block (if any) between the leaf and the root node. So
+  ** if the height of the input segment b-trees is N, and input segments
+  ** are merged eight at a time, updating the input segments at the end
+  ** of an incremental-merge requires writing (8*(1+N)) blocks. N is usually
+  ** small - often between 0 and 2. So the overhead of the incremental
+  ** merge is somewhere between 8 and 24 blocks. To avoid this overhead
+  ** dwarfing the actual productive work accomplished, the incremental merge
+  ** is only attempted if it will write at least 64 leaf blocks. Hence
+  ** nMinMerge.
+  **
+  ** Of course, updating the input segments also involves deleting a bunch
+  ** of blocks from the segments table. But this is not considered overhead
+  ** as it would also be required by a crisis-merge that used the same input
+  ** segments.
+  */
+  const u32 nMinMerge = 64;       /* Minimum amount of incr-merge work to do */
+
+  Fts3Table *p = (Fts3Table*)pVtab;
+  int rc;
+  i64 iLastRowid = sqlite3_last_insert_rowid(p->db);
+
+  rc = sqlite3Fts3PendingTermsFlush(p);
+  if( rc==SQLITE_OK
+   && p->nLeafAdd>(nMinMerge/16)
+   && p->nAutoincrmerge && p->nAutoincrmerge!=0xff
+  ){
+    int mxLevel = 0;              /* Maximum relative level value in db */
+    int A;                        /* Incr-merge parameter A */
+
+    rc = sqlite3Fts3MaxLevel(p, &mxLevel);
+    assert( rc==SQLITE_OK || mxLevel==0 );
+    A = p->nLeafAdd * mxLevel;
+    A += (A/2);
+    if( A>(int)nMinMerge ) rc = sqlite3Fts3Incrmerge(p, A, p->nAutoincrmerge);
+  }
+  sqlite3Fts3SegmentsClose(p);
+  sqlite3_set_last_insert_rowid(p->db, iLastRowid);
+  return rc;
+}
+
+/*
+** If it is currently unknown whether or not the FTS table has an %_stat
+** table (if p->bHasStat==2), attempt to determine this (set p->bHasStat
+** to 0 or 1). Return SQLITE_OK if successful, or an SQLite error code
+** if an error occurs.
+*/
+static int fts3SetHasStat(Fts3Table *p){
+  int rc = SQLITE_OK;
+  if( p->bHasStat==2 ){
+    char *zTbl = sqlite3_mprintf("%s_stat", p->zName);
+    if( zTbl ){
+      int res = sqlite3_table_column_metadata(p->db, p->zDb, zTbl, 0,0,0,0,0,0);
+      sqlite3_free(zTbl);
+      p->bHasStat = (res==SQLITE_OK);
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+  return rc;
+}
+
+/*
+** Implementation of xBegin() method.
+*/
+static int fts3BeginMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table*)pVtab;
+  int rc;
+  UNUSED_PARAMETER(pVtab);
+  assert( p->pSegments==0 );
+  assert( p->nPendingData==0 );
+  assert( p->inTransaction!=1 );
+  p->nLeafAdd = 0;
+  rc = fts3SetHasStat(p);
+#ifdef SQLITE_DEBUG
+  if( rc==SQLITE_OK ){
+    p->inTransaction = 1;
+    p->mxSavepoint = -1;
+  }
+#endif
+  return rc;
+}
+
+/*
+** Implementation of xCommit() method. This is a no-op. The contents of
+** the pending-terms hash-table have already been flushed into the database
+** by fts3SyncMethod().
+*/
+static int fts3CommitMethod(sqlite3_vtab *pVtab){
+  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
+  UNUSED_PARAMETER(pVtab);
+  assert( p->nPendingData==0 );
+  assert( p->inTransaction!=0 );
+  assert( p->pSegments==0 );
+  TESTONLY( p->inTransaction = 0 );
+  TESTONLY( p->mxSavepoint = -1; );
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xRollback(). Discard the contents of the pending-terms
+** hash-table. Any changes made to the database are reverted by SQLite.
+*/
+static int fts3RollbackMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table*)pVtab;
+  sqlite3Fts3PendingTermsClear(p);
+  assert( p->inTransaction!=0 );
+  TESTONLY( p->inTransaction = 0 );
+  TESTONLY( p->mxSavepoint = -1; );
+  return SQLITE_OK;
+}
+
+/*
+** When called, *ppPoslist must point to the byte immediately following the
+** end of a position-list. i.e. ( (*ppPoslist)[-1]==POS_END ). This function
+** moves *ppPoslist so that it instead points to the first byte of the
+** same position list.
+*/
+static void fts3ReversePoslist(char *pStart, char **ppPoslist){
+  char *p = &(*ppPoslist)[-2];
+  char c = 0;
+
+  /* Skip backwards passed any trailing 0x00 bytes added by NearTrim() */
+  while( p>pStart && (c=*p--)==0 );
+
+  /* Search backwards for a varint with value zero (the end of the previous
+  ** poslist). This is an 0x00 byte preceded by some byte that does not
+  ** have the 0x80 bit set.  */
+  while( p>pStart && (*p & 0x80) | c ){
+    c = *p--;
+  }
+  assert( p==pStart || c==0 );
+
+  /* At this point p points to that preceding byte without the 0x80 bit
+  ** set. So to find the start of the poslist, skip forward 2 bytes then
+  ** over a varint.
+  **
+  ** Normally. The other case is that p==pStart and the poslist to return
+  ** is the first in the doclist. In this case do not skip forward 2 bytes.
+  ** The second part of the if condition (c==0 && *ppPoslist>&p[2])
+  ** is required for cases where the first byte of a doclist and the
+  ** doclist is empty. For example, if the first docid is 10, a doclist
+  ** that begins with:
+  **
+  **   0x0A 0x00 <next docid delta varint>
+  */
+  if( p>pStart || (c==0 && *ppPoslist>&p[2]) ){ p = &p[2]; }
+  while( *p++&0x80 );
+  *ppPoslist = p;
+}
+
+/*
+** Helper function used by the implementation of the overloaded snippet(),
+** offsets() and optimize() SQL functions.
+**
+** If the value passed as the third argument is a blob of size
+** sizeof(Fts3Cursor*), then the blob contents are copied to the
+** output variable *ppCsr and SQLITE_OK is returned. Otherwise, an error
+** message is written to context pContext and SQLITE_ERROR returned. The
+** string passed via zFunc is used as part of the error message.
+*/
+static int fts3FunctionArg(
+  sqlite3_context *pContext,      /* SQL function call context */
+  const char *zFunc,              /* Function name */
+  sqlite3_value *pVal,            /* argv[0] passed to function */
+  Fts3Cursor **ppCsr              /* OUT: Store cursor handle here */
+){
+  int rc;
+  *ppCsr = (Fts3Cursor*)sqlite3_value_pointer(pVal, "fts3cursor");
+  if( (*ppCsr)!=0 ){
+    rc = SQLITE_OK;
+  }else{
+    char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
+    sqlite3_result_error(pContext, zErr, -1);
+    sqlite3_free(zErr);
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** Implementation of the snippet() function for FTS3
+*/
+static void fts3SnippetFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of apVal[] array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+  const char *zStart = "<b>";
+  const char *zEnd = "</b>";
+  const char *zEllipsis = "<b>...</b>";
+  int iCol = -1;
+  int nToken = 15;                /* Default number of tokens in snippet */
+
+  /* There must be at least one argument passed to this function (otherwise
+  ** the non-overloaded version would have been called instead of this one).
+  */
+  assert( nVal>=1 );
+
+  if( nVal>6 ){
+    sqlite3_result_error(pContext,
+        "wrong number of arguments to function snippet()", -1);
+    return;
+  }
+  if( fts3FunctionArg(pContext, "snippet", apVal[0], &pCsr) ) return;
+
+  switch( nVal ){
+    case 6: nToken = sqlite3_value_int(apVal[5]);
+            /* no break */ deliberate_fall_through
+    case 5: iCol = sqlite3_value_int(apVal[4]);
+            /* no break */ deliberate_fall_through
+    case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
+            /* no break */ deliberate_fall_through
+    case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
+            /* no break */ deliberate_fall_through
+    case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
+  }
+  if( !zEllipsis || !zEnd || !zStart ){
+    sqlite3_result_error_nomem(pContext);
+  }else if( nToken==0 ){
+    sqlite3_result_text(pContext, "", -1, SQLITE_STATIC);
+  }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
+    sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis, iCol, nToken);
+  }
+}
+
+/*
+** Implementation of the offsets() function for FTS3
+*/
+static void fts3OffsetsFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+
+  UNUSED_PARAMETER(nVal);
+
+  assert( nVal==1 );
+  if( fts3FunctionArg(pContext, "offsets", apVal[0], &pCsr) ) return;
+  assert( pCsr );
+  if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
+    sqlite3Fts3Offsets(pContext, pCsr);
+  }
+}
+
+/*
+** Implementation of the special optimize() function for FTS3. This
+** function merges all segments in the database to a single segment.
+** Example usage is:
+**
+**   SELECT optimize(t) FROM t LIMIT 1;
+**
+** where 't' is the name of an FTS3 table.
+*/
+static void fts3OptimizeFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  int rc;                         /* Return code */
+  Fts3Table *p;                   /* Virtual table handle */
+  Fts3Cursor *pCursor;            /* Cursor handle passed through apVal[0] */
+
+  UNUSED_PARAMETER(nVal);
+
+  assert( nVal==1 );
+  if( fts3FunctionArg(pContext, "optimize", apVal[0], &pCursor) ) return;
+  p = (Fts3Table *)pCursor->base.pVtab;
+  assert( p );
+
+  rc = sqlite3Fts3Optimize(p);
+
+  switch( rc ){
+    case SQLITE_OK:
+      sqlite3_result_text(pContext, "Index optimized", -1, SQLITE_STATIC);
+      break;
+    case SQLITE_DONE:
+      sqlite3_result_text(pContext, "Index already optimal", -1, SQLITE_STATIC);
+      break;
+    default:
+      sqlite3_result_error_code(pContext, rc);
+      break;
+  }
+}
+
+/*
+** Implementation of the matchinfo() function for FTS3
+*/
+static void fts3MatchinfoFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+  assert( nVal==1 || nVal==2 );
+  if( SQLITE_OK==fts3FunctionArg(pContext, "matchinfo", apVal[0], &pCsr) ){
+    const char *zArg = 0;
+    if( nVal>1 ){
+      zArg = (const char *)sqlite3_value_text(apVal[1]);
+    }
+    sqlite3Fts3Matchinfo(pContext, pCsr, zArg);
+  }
+}
+
+/*
+** This routine implements the xFindFunction method for the FTS3
+** virtual table.
+*/
+static int fts3FindFunctionMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Number of SQL function arguments */
+  const char *zName,              /* Name of SQL function */
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
+  void **ppArg                    /* Unused */
+){
+  struct Overloaded {
+    const char *zName;
+    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  } aOverload[] = {
+    { "snippet", fts3SnippetFunc },
+    { "offsets", fts3OffsetsFunc },
+    { "optimize", fts3OptimizeFunc },
+    { "matchinfo", fts3MatchinfoFunc },
+  };
+  int i;                          /* Iterator variable */
+
+  UNUSED_PARAMETER(pVtab);
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(ppArg);
+
+  for(i=0; i<SizeofArray(aOverload); i++){
+    if( strcmp(zName, aOverload[i].zName)==0 ){
+      *pxFunc = aOverload[i].xFunc;
+      return 1;
+    }
+  }
+
+  /* No function of the specified name was found. Return 0. */
+  return 0;
+}
+
+/*
+** Implementation of FTS3 xRename method. Rename an fts3 table.
+*/
+static int fts3RenameMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  const char *zName               /* New name of table */
+){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  sqlite3 *db = p->db;            /* Database connection */
+  int rc;                         /* Return Code */
+
+  /* At this point it must be known if the %_stat table exists or not.
+  ** So bHasStat may not be 2.  */
+  rc = fts3SetHasStat(p);
+
+  /* As it happens, the pending terms table is always empty here. This is
+  ** because an "ALTER TABLE RENAME TABLE" statement inside a transaction
+  ** always opens a savepoint transaction. And the xSavepoint() method
+  ** flushes the pending terms table. But leave the (no-op) call to
+  ** PendingTermsFlush() in in case that changes.
+  */
+  assert( p->nPendingData==0 );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3PendingTermsFlush(p);
+  }
+
+  p->bIgnoreSavepoint = 1;
+
+  if( p->zContentTbl==0 ){
+    fts3DbExec(&rc, db,
+      "ALTER TABLE %Q.'%q_content'  RENAME TO '%q_content';",
+      p->zDb, p->zName, zName
+    );
+  }
+
+  if( p->bHasDocsize ){
+    fts3DbExec(&rc, db,
+      "ALTER TABLE %Q.'%q_docsize'  RENAME TO '%q_docsize';",
+      p->zDb, p->zName, zName
+    );
+  }
+  if( p->bHasStat ){
+    fts3DbExec(&rc, db,
+      "ALTER TABLE %Q.'%q_stat'  RENAME TO '%q_stat';",
+      p->zDb, p->zName, zName
+    );
+  }
+  fts3DbExec(&rc, db,
+    "ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';",
+    p->zDb, p->zName, zName
+  );
+  fts3DbExec(&rc, db,
+    "ALTER TABLE %Q.'%q_segdir'   RENAME TO '%q_segdir';",
+    p->zDb, p->zName, zName
+  );
+
+  p->bIgnoreSavepoint = 0;
+  return rc;
+}
+
+/*
+** The xSavepoint() method.
+**
+** Flush the contents of the pending-terms table to disk.
+*/
+static int fts3SavepointMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  int rc = SQLITE_OK;
+  Fts3Table *pTab = (Fts3Table*)pVtab;
+  assert( pTab->inTransaction );
+  assert( pTab->mxSavepoint<=iSavepoint );
+  TESTONLY( pTab->mxSavepoint = iSavepoint );
+
+  if( pTab->bIgnoreSavepoint==0 ){
+    if( fts3HashCount(&pTab->aIndex[0].hPending)>0 ){
+      char *zSql = sqlite3_mprintf("INSERT INTO %Q.%Q(%Q) VALUES('flush')",
+          pTab->zDb, pTab->zName, pTab->zName
+          );
+      if( zSql ){
+        pTab->bIgnoreSavepoint = 1;
+        rc = sqlite3_exec(pTab->db, zSql, 0, 0, 0);
+        pTab->bIgnoreSavepoint = 0;
+        sqlite3_free(zSql);
+      }else{
+        rc = SQLITE_NOMEM;
+      }
+    }
+    if( rc==SQLITE_OK ){
+      pTab->iSavepoint = iSavepoint+1;
+    }
+  }
+  return rc;
+}
+
+/*
+** The xRelease() method.
+**
+** This is a no-op.
+*/
+static int fts3ReleaseMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts3Table *pTab = (Fts3Table*)pVtab;
+  assert( pTab->inTransaction );
+  assert( pTab->mxSavepoint >= iSavepoint );
+  TESTONLY( pTab->mxSavepoint = iSavepoint-1 );
+  pTab->iSavepoint = iSavepoint;
+  return SQLITE_OK;
+}
+
+/*
+** The xRollbackTo() method.
+**
+** Discard the contents of the pending terms table.
+*/
+static int fts3RollbackToMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts3Table *pTab = (Fts3Table*)pVtab;
+  UNUSED_PARAMETER(iSavepoint);
+  assert( pTab->inTransaction );
+  TESTONLY( pTab->mxSavepoint = iSavepoint );
+  if( (iSavepoint+1)<=pTab->iSavepoint ){
+    sqlite3Fts3PendingTermsClear(pTab);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return true if zName is the extension on one of the shadow tables used
+** by this module.
+*/
+static int fts3ShadowName(const char *zName){
+  static const char *azName[] = {
+    "content", "docsize", "segdir", "segments", "stat",
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
+    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Implementation of the xIntegrity() method on the FTS3/FTS4 virtual
+** table.
+*/
+static int fts3IntegrityMethod(
+  sqlite3_vtab *pVtab,      /* The virtual table to be checked */
+  const char *zSchema,      /* Name of schema in which pVtab lives */
+  const char *zTabname,     /* Name of the pVTab table */
+  int isQuick,              /* True if this is a quick_check */
+  char **pzErr              /* Write error message here */
+){
+  Fts3Table *p = (Fts3Table*)pVtab;
+  int rc = SQLITE_OK;
+  int bOk = 0;
+
+  UNUSED_PARAMETER(isQuick);
+  rc = sqlite3Fts3IntegrityCheck(p, &bOk);
+  assert( rc!=SQLITE_CORRUPT_VTAB );
+  if( rc==SQLITE_ERROR || (rc&0xFF)==SQLITE_CORRUPT ){
+    *pzErr = sqlite3_mprintf("unable to validate the inverted index for"
+                             " FTS%d table %s.%s: %s",
+                p->bFts4 ? 4 : 3, zSchema, zTabname, sqlite3_errstr(rc));
+    if( *pzErr ) rc = SQLITE_OK;
+  }else if( rc==SQLITE_OK && bOk==0 ){
+    *pzErr = sqlite3_mprintf("malformed inverted index for FTS%d table %s.%s",
+                p->bFts4 ? 4 : 3, zSchema, zTabname);
+    if( *pzErr==0 ) rc = SQLITE_NOMEM;
+  }
+  sqlite3Fts3SegmentsClose(p);
+  return rc;
+}
+
+
+
+static const sqlite3_module fts3Module = {
+  /* iVersion      */ 4,
+  /* xCreate       */ fts3CreateMethod,
+  /* xConnect      */ fts3ConnectMethod,
+  /* xBestIndex    */ fts3BestIndexMethod,
+  /* xDisconnect   */ fts3DisconnectMethod,
+  /* xDestroy      */ fts3DestroyMethod,
+  /* xOpen         */ fts3OpenMethod,
+  /* xClose        */ fts3CloseMethod,
+  /* xFilter       */ fts3FilterMethod,
+  /* xNext         */ fts3NextMethod,
+  /* xEof          */ fts3EofMethod,
+  /* xColumn       */ fts3ColumnMethod,
+  /* xRowid        */ fts3RowidMethod,
+  /* xUpdate       */ fts3UpdateMethod,
+  /* xBegin        */ fts3BeginMethod,
+  /* xSync         */ fts3SyncMethod,
+  /* xCommit       */ fts3CommitMethod,
+  /* xRollback     */ fts3RollbackMethod,
+  /* xFindFunction */ fts3FindFunctionMethod,
+  /* xRename */       fts3RenameMethod,
+  /* xSavepoint    */ fts3SavepointMethod,
+  /* xRelease      */ fts3ReleaseMethod,
+  /* xRollbackTo   */ fts3RollbackToMethod,
+  /* xShadowName   */ fts3ShadowName,
+  /* xIntegrity    */ fts3IntegrityMethod,
+};
+
+/*
+** This function is registered as the module destructor (called when an
+** FTS3 enabled database connection is closed). It frees the memory
+** allocated for the tokenizer hash table.
+*/
+static void hashDestroy(void *p){
+  Fts3HashWrapper *pHash = (Fts3HashWrapper *)p;
+  pHash->nRef--;
+  if( pHash->nRef<=0 ){
+    sqlite3Fts3HashClear(&pHash->hash);
+    sqlite3_free(pHash);
+  }
+}
+
+/*
+** The fts3 built-in tokenizers - "simple", "porter" and "icu"- are
+** implemented in files fts3_tokenizer1.c, fts3_porter.c and fts3_icu.c
+** respectively. The following three forward declarations are for functions
+** declared in these files used to retrieve the respective implementations.
+**
+** Calling sqlite3Fts3SimpleTokenizerModule() sets the value pointed
+** to by the argument to point to the "simple" tokenizer implementation.
+** And so on.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+SQLITE_PRIVATE void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const**ppModule);
+#endif
+#ifdef SQLITE_ENABLE_ICU
+SQLITE_PRIVATE void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+#endif
+
+/*
+** Initialize the fts3 extension. If this extension is built as part
+** of the sqlite library, then this function is called directly by
+** SQLite. If fts3 is built as a dynamically loadable extension, this
+** function is called by the sqlite3_extension_init() entry point.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db){
+  int rc = SQLITE_OK;
+  Fts3HashWrapper *pHash = 0;
+  const sqlite3_tokenizer_module *pSimple = 0;
+  const sqlite3_tokenizer_module *pPorter = 0;
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+  const sqlite3_tokenizer_module *pUnicode = 0;
+#endif
+
+#ifdef SQLITE_ENABLE_ICU
+  const sqlite3_tokenizer_module *pIcu = 0;
+  sqlite3Fts3IcuTokenizerModule(&pIcu);
+#endif
+
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+  sqlite3Fts3UnicodeTokenizer(&pUnicode);
+#endif
+
+#ifdef SQLITE_TEST
+  rc = sqlite3Fts3InitTerm(db);
+  if( rc!=SQLITE_OK ) return rc;
+#endif
+
+  rc = sqlite3Fts3InitAux(db);
+  if( rc!=SQLITE_OK ) return rc;
+
+  sqlite3Fts3SimpleTokenizerModule(&pSimple);
+  sqlite3Fts3PorterTokenizerModule(&pPorter);
+
+  /* Allocate and initialize the hash-table used to store tokenizers. */
+  pHash = sqlite3_malloc(sizeof(Fts3HashWrapper));
+  if( !pHash ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3Fts3HashInit(&pHash->hash, FTS3_HASH_STRING, 1);
+    pHash->nRef = 0;
+  }
+
+  /* Load the built-in tokenizers into the hash table */
+  if( rc==SQLITE_OK ){
+    if( sqlite3Fts3HashInsert(&pHash->hash, "simple", 7, (void *)pSimple)
+     || sqlite3Fts3HashInsert(&pHash->hash, "porter", 7, (void *)pPorter)
+
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+     || sqlite3Fts3HashInsert(&pHash->hash, "unicode61", 10, (void *)pUnicode)
+#endif
+#ifdef SQLITE_ENABLE_ICU
+     || (pIcu && sqlite3Fts3HashInsert(&pHash->hash, "icu", 4, (void *)pIcu))
+#endif
+    ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+#ifdef SQLITE_TEST
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3ExprInitTestInterface(db, &pHash->hash);
+  }
+#endif
+
+  /* Create the virtual table wrapper around the hash-table and overload
+  ** the four scalar functions. If this is successful, register the
+  ** module with sqlite.
+  */
+  if( SQLITE_OK==rc
+   && SQLITE_OK==(rc=sqlite3Fts3InitHashTable(db,&pHash->hash,"fts3_tokenizer"))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 2))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
+  ){
+    pHash->nRef++;
+    rc = sqlite3_create_module_v2(
+        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
+    );
+    if( rc==SQLITE_OK ){
+      pHash->nRef++;
+      rc = sqlite3_create_module_v2(
+          db, "fts4", &fts3Module, (void *)pHash, hashDestroy
+      );
+    }
+    if( rc==SQLITE_OK ){
+      pHash->nRef++;
+      rc = sqlite3Fts3InitTok(db, (void *)pHash, hashDestroy);
+    }
+    return rc;
+  }
+
+
+  /* An error has occurred. Delete the hash table and return the error code. */
+  assert( rc!=SQLITE_OK );
+  if( pHash ){
+    sqlite3Fts3HashClear(&pHash->hash);
+    sqlite3_free(pHash);
+  }
+  return rc;
+}
+
+/*
+** Allocate an Fts3MultiSegReader for each token in the expression headed
+** by pExpr.
+**
+** An Fts3SegReader object is a cursor that can seek or scan a range of
+** entries within a single segment b-tree. An Fts3MultiSegReader uses multiple
+** Fts3SegReader objects internally to provide an interface to seek or scan
+** within the union of all segments of a b-tree. Hence the name.
+**
+** If the allocated Fts3MultiSegReader just seeks to a single entry in a
+** segment b-tree (if the term is not a prefix or it is a prefix for which
+** there exists prefix b-tree of the right length) then it may be traversed
+** and merged incrementally. Otherwise, it has to be merged into an in-memory
+** doclist and then traversed.
+*/
+static void fts3EvalAllocateReaders(
+  Fts3Cursor *pCsr,               /* FTS cursor handle */
+  Fts3Expr *pExpr,                /* Allocate readers for this expression */
+  int *pnToken,                   /* OUT: Total number of tokens in phrase. */
+  int *pnOr,                      /* OUT: Total number of OR nodes in expr. */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( pExpr && SQLITE_OK==*pRc ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      int i;
+      int nToken = pExpr->pPhrase->nToken;
+      *pnToken += nToken;
+      for(i=0; i<nToken; i++){
+        Fts3PhraseToken *pToken = &pExpr->pPhrase->aToken[i];
+        int rc = fts3TermSegReaderCursor(pCsr,
+            pToken->z, pToken->n, pToken->isPrefix, &pToken->pSegcsr
+        );
+        if( rc!=SQLITE_OK ){
+          *pRc = rc;
+          return;
+        }
+      }
+      assert( pExpr->pPhrase->iDoclistToken==0 );
+      pExpr->pPhrase->iDoclistToken = -1;
+    }else{
+      *pnOr += (pExpr->eType==FTSQUERY_OR);
+      fts3EvalAllocateReaders(pCsr, pExpr->pLeft, pnToken, pnOr, pRc);
+      fts3EvalAllocateReaders(pCsr, pExpr->pRight, pnToken, pnOr, pRc);
+    }
+  }
+}
+
+/*
+** Arguments pList/nList contain the doclist for token iToken of phrase p.
+** It is merged into the main doclist stored in p->doclist.aAll/nAll.
+**
+** This function assumes that pList points to a buffer allocated using
+** sqlite3_malloc(). This function takes responsibility for eventually
+** freeing the buffer.
+**
+** SQLITE_OK is returned if successful, or SQLITE_NOMEM if an error occurs.
+*/
+static int fts3EvalPhraseMergeToken(
+  Fts3Table *pTab,                /* FTS Table pointer */
+  Fts3Phrase *p,                  /* Phrase to merge pList/nList into */
+  int iToken,                     /* Token pList/nList corresponds to */
+  char *pList,                    /* Pointer to doclist */
+  int nList                       /* Number of bytes in pList */
+){
+  int rc = SQLITE_OK;
+  assert( iToken!=p->iDoclistToken );
+
+  if( pList==0 ){
+    sqlite3_free(p->doclist.aAll);
+    p->doclist.aAll = 0;
+    p->doclist.nAll = 0;
+  }
+
+  else if( p->iDoclistToken<0 ){
+    p->doclist.aAll = pList;
+    p->doclist.nAll = nList;
+  }
+
+  else if( p->doclist.aAll==0 ){
+    sqlite3_free(pList);
+  }
+
+  else {
+    char *pLeft;
+    char *pRight;
+    int nLeft;
+    int nRight;
+    int nDiff;
+
+    if( p->iDoclistToken<iToken ){
+      pLeft = p->doclist.aAll;
+      nLeft = p->doclist.nAll;
+      pRight = pList;
+      nRight = nList;
+      nDiff = iToken - p->iDoclistToken;
+    }else{
+      pRight = p->doclist.aAll;
+      nRight = p->doclist.nAll;
+      pLeft = pList;
+      nLeft = nList;
+      nDiff = p->iDoclistToken - iToken;
+    }
+
+    rc = fts3DoclistPhraseMerge(
+        pTab->bDescIdx, nDiff, pLeft, nLeft, &pRight, &nRight
+    );
+    sqlite3_free(pLeft);
+    p->doclist.aAll = pRight;
+    p->doclist.nAll = nRight;
+  }
+
+  if( iToken>p->iDoclistToken ) p->iDoclistToken = iToken;
+  return rc;
+}
+
+/*
+** Load the doclist for phrase p into p->doclist.aAll/nAll. The loaded doclist
+** does not take deferred tokens into account.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3EvalPhraseLoad(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Phrase *p                   /* Phrase object */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int iToken;
+  int rc = SQLITE_OK;
+
+  for(iToken=0; rc==SQLITE_OK && iToken<p->nToken; iToken++){
+    Fts3PhraseToken *pToken = &p->aToken[iToken];
+    assert( pToken->pDeferred==0 || pToken->pSegcsr==0 );
+
+    if( pToken->pSegcsr ){
+      int nThis = 0;
+      char *pThis = 0;
+      rc = fts3TermSelect(pTab, pToken, p->iColumn, &nThis, &pThis);
+      if( rc==SQLITE_OK ){
+        rc = fts3EvalPhraseMergeToken(pTab, p, iToken, pThis, nThis);
+      }
+    }
+    assert( pToken->pSegcsr==0 );
+  }
+
+  return rc;
+}
+
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+/*
+** This function is called on each phrase after the position lists for
+** any deferred tokens have been loaded into memory. It updates the phrases
+** current position list to include only those positions that are really
+** instances of the phrase (after considering deferred tokens). If this
+** means that the phrase does not appear in the current row, doclist.pList
+** and doclist.nList are both zeroed.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
+  int iToken;                     /* Used to iterate through phrase tokens */
+  char *aPoslist = 0;             /* Position list for deferred tokens */
+  int nPoslist = 0;               /* Number of bytes in aPoslist */
+  int iPrev = -1;                 /* Token number of previous deferred token */
+  char *aFree = (pPhrase->doclist.bFreeList ? pPhrase->doclist.pList : 0);
+
+  for(iToken=0; iToken<pPhrase->nToken; iToken++){
+    Fts3PhraseToken *pToken = &pPhrase->aToken[iToken];
+    Fts3DeferredToken *pDeferred = pToken->pDeferred;
+
+    if( pDeferred ){
+      char *pList;
+      int nList;
+      int rc = sqlite3Fts3DeferredTokenList(pDeferred, &pList, &nList);
+      if( rc!=SQLITE_OK ) return rc;
+
+      if( pList==0 ){
+        sqlite3_free(aPoslist);
+        sqlite3_free(aFree);
+        pPhrase->doclist.pList = 0;
+        pPhrase->doclist.nList = 0;
+        return SQLITE_OK;
+
+      }else if( aPoslist==0 ){
+        aPoslist = pList;
+        nPoslist = nList;
+
+      }else{
+        char *aOut = pList;
+        char *p1 = aPoslist;
+        char *p2 = aOut;
+
+        assert( iPrev>=0 );
+        fts3PoslistPhraseMerge(&aOut, iToken-iPrev, 0, 1, &p1, &p2);
+        sqlite3_free(aPoslist);
+        aPoslist = pList;
+        nPoslist = (int)(aOut - aPoslist);
+        if( nPoslist==0 ){
+          sqlite3_free(aPoslist);
+          sqlite3_free(aFree);
+          pPhrase->doclist.pList = 0;
+          pPhrase->doclist.nList = 0;
+          return SQLITE_OK;
+        }
+      }
+      iPrev = iToken;
+    }
+  }
+
+  if( iPrev>=0 ){
+    int nMaxUndeferred = pPhrase->iDoclistToken;
+    if( nMaxUndeferred<0 ){
+      pPhrase->doclist.pList = aPoslist;
+      pPhrase->doclist.nList = nPoslist;
+      pPhrase->doclist.iDocid = pCsr->iPrevId;
+      pPhrase->doclist.bFreeList = 1;
+    }else{
+      int nDistance;
+      char *p1;
+      char *p2;
+      char *aOut;
+
+      if( nMaxUndeferred>iPrev ){
+        p1 = aPoslist;
+        p2 = pPhrase->doclist.pList;
+        nDistance = nMaxUndeferred - iPrev;
+      }else{
+        p1 = pPhrase->doclist.pList;
+        p2 = aPoslist;
+        nDistance = iPrev - nMaxUndeferred;
+      }
+
+      aOut = (char *)sqlite3Fts3MallocZero(nPoslist+FTS3_BUFFER_PADDING);
+      if( !aOut ){
+        sqlite3_free(aPoslist);
+        return SQLITE_NOMEM;
+      }
+
+      pPhrase->doclist.pList = aOut;
+      assert( p1 && p2 );
+      if( fts3PoslistPhraseMerge(&aOut, nDistance, 0, 1, &p1, &p2) ){
+        pPhrase->doclist.bFreeList = 1;
+        pPhrase->doclist.nList = (int)(aOut - pPhrase->doclist.pList);
+      }else{
+        sqlite3_free(aOut);
+        pPhrase->doclist.pList = 0;
+        pPhrase->doclist.nList = 0;
+      }
+      sqlite3_free(aPoslist);
+    }
+  }
+
+  if( pPhrase->doclist.pList!=aFree ) sqlite3_free(aFree);
+  return SQLITE_OK;
+}
+#endif /* SQLITE_DISABLE_FTS4_DEFERRED */
+
+/*
+** Maximum number of tokens a phrase may have to be considered for the
+** incremental doclists strategy.
+*/
+#define MAX_INCR_PHRASE_TOKENS 4
+
+/*
+** This function is called for each Fts3Phrase in a full-text query
+** expression to initialize the mechanism for returning rows. Once this
+** function has been called successfully on an Fts3Phrase, it may be
+** used with fts3EvalPhraseNext() to iterate through the matching docids.
+**
+** If parameter bOptOk is true, then the phrase may (or may not) use the
+** incremental loading strategy. Otherwise, the entire doclist is loaded into
+** memory within this call.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3EvalPhraseStart(Fts3Cursor *pCsr, int bOptOk, Fts3Phrase *p){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;             /* Error code */
+  int i;
+
+  /* Determine if doclists may be loaded from disk incrementally. This is
+  ** possible if the bOptOk argument is true, the FTS doclists will be
+  ** scanned in forward order, and the phrase consists of
+  ** MAX_INCR_PHRASE_TOKENS or fewer tokens, none of which are are "^first"
+  ** tokens or prefix tokens that cannot use a prefix-index.  */
+  int bHaveIncr = 0;
+  int bIncrOk = (bOptOk
+   && pCsr->bDesc==pTab->bDescIdx
+   && p->nToken<=MAX_INCR_PHRASE_TOKENS && p->nToken>0
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+   && pTab->bNoIncrDoclist==0
+#endif
+  );
+  for(i=0; bIncrOk==1 && i<p->nToken; i++){
+    Fts3PhraseToken *pToken = &p->aToken[i];
+    if( pToken->bFirst || (pToken->pSegcsr!=0 && !pToken->pSegcsr->bLookup) ){
+      bIncrOk = 0;
+    }
+    if( pToken->pSegcsr ) bHaveIncr = 1;
+  }
+
+  if( bIncrOk && bHaveIncr ){
+    /* Use the incremental approach. */
+    int iCol = (p->iColumn >= pTab->nColumn ? -1 : p->iColumn);
+    for(i=0; rc==SQLITE_OK && i<p->nToken; i++){
+      Fts3PhraseToken *pToken = &p->aToken[i];
+      Fts3MultiSegReader *pSegcsr = pToken->pSegcsr;
+      if( pSegcsr ){
+        rc = sqlite3Fts3MsrIncrStart(pTab, pSegcsr, iCol, pToken->z, pToken->n);
+      }
+    }
+    p->bIncr = 1;
+  }else{
+    /* Load the full doclist for the phrase into memory. */
+    rc = fts3EvalPhraseLoad(pCsr, p);
+    p->bIncr = 0;
+  }
+
+  assert( rc!=SQLITE_OK || p->nToken<1 || p->aToken[0].pSegcsr==0 || p->bIncr );
+  return rc;
+}
+
+/*
+** This function is used to iterate backwards (from the end to start)
+** through doclists. It is used by this module to iterate through phrase
+** doclists in reverse and by the fts3_write.c module to iterate through
+** pending-terms lists when writing to databases with "order=desc".
+**
+** The doclist may be sorted in ascending (parameter bDescIdx==0) or
+** descending (parameter bDescIdx==1) order of docid. Regardless, this
+** function iterates from the end of the doclist to the beginning.
+*/
+SQLITE_PRIVATE void sqlite3Fts3DoclistPrev(
+  int bDescIdx,                   /* True if the doclist is desc */
+  char *aDoclist,                 /* Pointer to entire doclist */
+  int nDoclist,                   /* Length of aDoclist in bytes */
+  char **ppIter,                  /* IN/OUT: Iterator pointer */
+  sqlite3_int64 *piDocid,         /* IN/OUT: Docid pointer */
+  int *pnList,                    /* OUT: List length pointer */
+  u8 *pbEof                       /* OUT: End-of-file flag */
+){
+  char *p = *ppIter;
+
+  assert( nDoclist>0 );
+  assert( *pbEof==0 );
+  assert_fts3_nc( p || *piDocid==0 );
+  assert( !p || (p>aDoclist && p<&aDoclist[nDoclist]) );
+
+  if( p==0 ){
+    sqlite3_int64 iDocid = 0;
+    char *pNext = 0;
+    char *pDocid = aDoclist;
+    char *pEnd = &aDoclist[nDoclist];
+    int iMul = 1;
+
+    while( pDocid<pEnd ){
+      sqlite3_int64 iDelta;
+      pDocid += sqlite3Fts3GetVarint(pDocid, &iDelta);
+      iDocid += (iMul * iDelta);
+      pNext = pDocid;
+      fts3PoslistCopy(0, &pDocid);
+      while( pDocid<pEnd && *pDocid==0 ) pDocid++;
+      iMul = (bDescIdx ? -1 : 1);
+    }
+
+    *pnList = (int)(pEnd - pNext);
+    *ppIter = pNext;
+    *piDocid = iDocid;
+  }else{
+    int iMul = (bDescIdx ? -1 : 1);
+    sqlite3_int64 iDelta;
+    fts3GetReverseVarint(&p, aDoclist, &iDelta);
+    *piDocid -= (iMul * iDelta);
+
+    if( p==aDoclist ){
+      *pbEof = 1;
+    }else{
+      char *pSave = p;
+      fts3ReversePoslist(aDoclist, &p);
+      *pnList = (int)(pSave - p);
+    }
+    *ppIter = p;
+  }
+}
+
+/*
+** Iterate forwards through a doclist.
+*/
+SQLITE_PRIVATE void sqlite3Fts3DoclistNext(
+  int bDescIdx,                   /* True if the doclist is desc */
+  char *aDoclist,                 /* Pointer to entire doclist */
+  int nDoclist,                   /* Length of aDoclist in bytes */
+  char **ppIter,                  /* IN/OUT: Iterator pointer */
+  sqlite3_int64 *piDocid,         /* IN/OUT: Docid pointer */
+  u8 *pbEof                       /* OUT: End-of-file flag */
+){
+  char *p = *ppIter;
+
+  assert( nDoclist>0 );
+  assert( *pbEof==0 );
+  assert_fts3_nc( p || *piDocid==0 );
+  assert( !p || (p>=aDoclist && p<=&aDoclist[nDoclist]) );
+
+  if( p==0 ){
+    p = aDoclist;
+    p += sqlite3Fts3GetVarint(p, piDocid);
+  }else{
+    fts3PoslistCopy(0, &p);
+    while( p<&aDoclist[nDoclist] && *p==0 ) p++;
+    if( p>=&aDoclist[nDoclist] ){
+      *pbEof = 1;
+    }else{
+      sqlite3_int64 iVar;
+      p += sqlite3Fts3GetVarint(p, &iVar);
+      *piDocid += ((bDescIdx ? -1 : 1) * iVar);
+    }
+  }
+
+  *ppIter = p;
+}
+
+/*
+** Advance the iterator pDL to the next entry in pDL->aAll/nAll. Set *pbEof
+** to true if EOF is reached.
+*/
+static void fts3EvalDlPhraseNext(
+  Fts3Table *pTab,
+  Fts3Doclist *pDL,
+  u8 *pbEof
+){
+  char *pIter;                            /* Used to iterate through aAll */
+  char *pEnd;                             /* 1 byte past end of aAll */
+
+  if( pDL->pNextDocid ){
+    pIter = pDL->pNextDocid;
+    assert( pDL->aAll!=0 || pIter==0 );
+  }else{
+    pIter = pDL->aAll;
+  }
+
+  if( pIter==0 || pIter>=(pEnd = pDL->aAll + pDL->nAll) ){
+    /* We have already reached the end of this doclist. EOF. */
+    *pbEof = 1;
+  }else{
+    sqlite3_int64 iDelta;
+    pIter += sqlite3Fts3GetVarint(pIter, &iDelta);
+    if( pTab->bDescIdx==0 || pDL->pNextDocid==0 ){
+      pDL->iDocid += iDelta;
+    }else{
+      pDL->iDocid -= iDelta;
+    }
+    pDL->pList = pIter;
+    fts3PoslistCopy(0, &pIter);
+    pDL->nList = (int)(pIter - pDL->pList);
+
+    /* pIter now points just past the 0x00 that terminates the position-
+    ** list for document pDL->iDocid. However, if this position-list was
+    ** edited in place by fts3EvalNearTrim(), then pIter may not actually
+    ** point to the start of the next docid value. The following line deals
+    ** with this case by advancing pIter past the zero-padding added by
+    ** fts3EvalNearTrim().  */
+    while( pIter<pEnd && *pIter==0 ) pIter++;
+
+    pDL->pNextDocid = pIter;
+    assert( pIter>=&pDL->aAll[pDL->nAll] || *pIter );
+    *pbEof = 0;
+  }
+}
+
+/*
+** Helper type used by fts3EvalIncrPhraseNext() and incrPhraseTokenNext().
+*/
+typedef struct TokenDoclist TokenDoclist;
+struct TokenDoclist {
+  int bIgnore;
+  sqlite3_int64 iDocid;
+  char *pList;
+  int nList;
+};
+
+/*
+** Token pToken is an incrementally loaded token that is part of a
+** multi-token phrase. Advance it to the next matching document in the
+** database and populate output variable *p with the details of the new
+** entry. Or, if the iterator has reached EOF, set *pbEof to true.
+**
+** If an error occurs, return an SQLite error code. Otherwise, return
+** SQLITE_OK.
+*/
+static int incrPhraseTokenNext(
+  Fts3Table *pTab,                /* Virtual table handle */
+  Fts3Phrase *pPhrase,            /* Phrase to advance token of */
+  int iToken,                     /* Specific token to advance */
+  TokenDoclist *p,                /* OUT: Docid and doclist for new entry */
+  u8 *pbEof                       /* OUT: True if iterator is at EOF */
+){
+  int rc = SQLITE_OK;
+
+  if( pPhrase->iDoclistToken==iToken ){
+    assert( p->bIgnore==0 );
+    assert( pPhrase->aToken[iToken].pSegcsr==0 );
+    fts3EvalDlPhraseNext(pTab, &pPhrase->doclist, pbEof);
+    p->pList = pPhrase->doclist.pList;
+    p->nList = pPhrase->doclist.nList;
+    p->iDocid = pPhrase->doclist.iDocid;
+  }else{
+    Fts3PhraseToken *pToken = &pPhrase->aToken[iToken];
+    assert( pToken->pDeferred==0 );
+    assert( pToken->pSegcsr || pPhrase->iDoclistToken>=0 );
+    if( pToken->pSegcsr ){
+      assert( p->bIgnore==0 );
+      rc = sqlite3Fts3MsrIncrNext(
+          pTab, pToken->pSegcsr, &p->iDocid, &p->pList, &p->nList
+      );
+      if( p->pList==0 ) *pbEof = 1;
+    }else{
+      p->bIgnore = 1;
+    }
+  }
+
+  return rc;
+}
+
+
+/*
+** The phrase iterator passed as the second argument:
+**
+**   * features at least one token that uses an incremental doclist, and
+**
+**   * does not contain any deferred tokens.
+**
+** Advance it to the next matching documnent in the database and populate
+** the Fts3Doclist.pList and nList fields.
+**
+** If there is no "next" entry and no error occurs, then *pbEof is set to
+** 1 before returning. Otherwise, if no error occurs and the iterator is
+** successfully advanced, *pbEof is set to 0.
+**
+** If an error occurs, return an SQLite error code. Otherwise, return
+** SQLITE_OK.
+*/
+static int fts3EvalIncrPhraseNext(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Phrase *p,                  /* Phrase object to advance to next docid */
+  u8 *pbEof                       /* OUT: Set to 1 if EOF */
+){
+  int rc = SQLITE_OK;
+  Fts3Doclist *pDL = &p->doclist;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  u8 bEof = 0;
+
+  /* This is only called if it is guaranteed that the phrase has at least
+  ** one incremental token. In which case the bIncr flag is set. */
+  assert( p->bIncr==1 );
+
+  if( p->nToken==1 ){
+    rc = sqlite3Fts3MsrIncrNext(pTab, p->aToken[0].pSegcsr,
+        &pDL->iDocid, &pDL->pList, &pDL->nList
+    );
+    if( pDL->pList==0 ) bEof = 1;
+  }else{
+    int bDescDoclist = pCsr->bDesc;
+    struct TokenDoclist a[MAX_INCR_PHRASE_TOKENS];
+
+    memset(a, 0, sizeof(a));
+    assert( p->nToken<=MAX_INCR_PHRASE_TOKENS );
+    assert( p->iDoclistToken<MAX_INCR_PHRASE_TOKENS );
+
+    while( bEof==0 ){
+      int bMaxSet = 0;
+      sqlite3_int64 iMax = 0;     /* Largest docid for all iterators */
+      int i;                      /* Used to iterate through tokens */
+
+      /* Advance the iterator for each token in the phrase once. */
+      for(i=0; rc==SQLITE_OK && i<p->nToken && bEof==0; i++){
+        rc = incrPhraseTokenNext(pTab, p, i, &a[i], &bEof);
+        if( a[i].bIgnore==0 && (bMaxSet==0 || DOCID_CMP(iMax, a[i].iDocid)<0) ){
+          iMax = a[i].iDocid;
+          bMaxSet = 1;
+        }
+      }
+      assert( rc!=SQLITE_OK || (p->nToken>=1 && a[p->nToken-1].bIgnore==0) );
+      assert( rc!=SQLITE_OK || bMaxSet );
+
+      /* Keep advancing iterators until they all point to the same document */
+      for(i=0; i<p->nToken; i++){
+        while( rc==SQLITE_OK && bEof==0
+            && a[i].bIgnore==0 && DOCID_CMP(a[i].iDocid, iMax)<0
+        ){
+          rc = incrPhraseTokenNext(pTab, p, i, &a[i], &bEof);
+          if( DOCID_CMP(a[i].iDocid, iMax)>0 ){
+            iMax = a[i].iDocid;
+            i = 0;
+          }
+        }
+      }
+
+      /* Check if the current entries really are a phrase match */
+      if( bEof==0 ){
+        int nList = 0;
+        int nByte = a[p->nToken-1].nList;
+        char *aDoclist = sqlite3_malloc64((i64)nByte+FTS3_BUFFER_PADDING);
+        if( !aDoclist ) return SQLITE_NOMEM;
+        memcpy(aDoclist, a[p->nToken-1].pList, nByte+1);
+        memset(&aDoclist[nByte], 0, FTS3_BUFFER_PADDING);
+
+        for(i=0; i<(p->nToken-1); i++){
+          if( a[i].bIgnore==0 ){
+            char *pL = a[i].pList;
+            char *pR = aDoclist;
+            char *pOut = aDoclist;
+            int nDist = p->nToken-1-i;
+            int res = fts3PoslistPhraseMerge(&pOut, nDist, 0, 1, &pL, &pR);
+            if( res==0 ) break;
+            nList = (int)(pOut - aDoclist);
+          }
+        }
+        if( i==(p->nToken-1) ){
+          pDL->iDocid = iMax;
+          pDL->pList = aDoclist;
+          pDL->nList = nList;
+          pDL->bFreeList = 1;
+          break;
+        }
+        sqlite3_free(aDoclist);
+      }
+    }
+  }
+
+  *pbEof = bEof;
+  return rc;
+}
+
+/*
+** Attempt to move the phrase iterator to point to the next matching docid.
+** If an error occurs, return an SQLite error code. Otherwise, return
+** SQLITE_OK.
+**
+** If there is no "next" entry and no error occurs, then *pbEof is set to
+** 1 before returning. Otherwise, if no error occurs and the iterator is
+** successfully advanced, *pbEof is set to 0.
+*/
+static int fts3EvalPhraseNext(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Phrase *p,                  /* Phrase object to advance to next docid */
+  u8 *pbEof                       /* OUT: Set to 1 if EOF */
+){
+  int rc = SQLITE_OK;
+  Fts3Doclist *pDL = &p->doclist;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+
+  if( p->bIncr ){
+    rc = fts3EvalIncrPhraseNext(pCsr, p, pbEof);
+  }else if( pCsr->bDesc!=pTab->bDescIdx && pDL->nAll ){
+    sqlite3Fts3DoclistPrev(pTab->bDescIdx, pDL->aAll, pDL->nAll,
+        &pDL->pNextDocid, &pDL->iDocid, &pDL->nList, pbEof
+    );
+    pDL->pList = pDL->pNextDocid;
+  }else{
+    fts3EvalDlPhraseNext(pTab, pDL, pbEof);
+  }
+
+  return rc;
+}
+
+/*
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, fts3EvalPhraseStart() is called on all phrases within the
+** expression. Also the Fts3Expr.bDeferred variable is set to true for any
+** expressions for which all descendent tokens are deferred.
+**
+** If parameter bOptOk is zero, then it is guaranteed that the
+** Fts3Phrase.doclist.aAll/nAll variables contain the entire doclist for
+** each phrase in the expression (subject to deferred token processing).
+** Or, if bOptOk is non-zero, then one or more tokens within the expression
+** may be loaded incrementally, meaning doclist.aAll/nAll is not available.
+**
+** If an error occurs within this function, *pRc is set to an SQLite error
+** code before returning.
+*/
+static void fts3EvalStartReaders(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pExpr,                /* Expression to initialize phrases in */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( pExpr && SQLITE_OK==*pRc ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      int nToken = pExpr->pPhrase->nToken;
+      if( nToken ){
+        int i;
+        for(i=0; i<nToken; i++){
+          if( pExpr->pPhrase->aToken[i].pDeferred==0 ) break;
+        }
+        pExpr->bDeferred = (i==nToken);
+      }
+      *pRc = fts3EvalPhraseStart(pCsr, 1, pExpr->pPhrase);
+    }else{
+      fts3EvalStartReaders(pCsr, pExpr->pLeft, pRc);
+      fts3EvalStartReaders(pCsr, pExpr->pRight, pRc);
+      pExpr->bDeferred = (pExpr->pLeft->bDeferred && pExpr->pRight->bDeferred);
+    }
+  }
+}
+
+/*
+** An array of the following structures is assembled as part of the process
+** of selecting tokens to defer before the query starts executing (as part
+** of the xFilter() method). There is one element in the array for each
+** token in the FTS expression.
+**
+** Tokens are divided into AND/NEAR clusters. All tokens in a cluster belong
+** to phrases that are connected only by AND and NEAR operators (not OR or
+** NOT). When determining tokens to defer, each AND/NEAR cluster is considered
+** separately. The root of a tokens AND/NEAR cluster is stored in
+** Fts3TokenAndCost.pRoot.
+*/
+typedef struct Fts3TokenAndCost Fts3TokenAndCost;
+struct Fts3TokenAndCost {
+  Fts3Phrase *pPhrase;            /* The phrase the token belongs to */
+  int iToken;                     /* Position of token in phrase */
+  Fts3PhraseToken *pToken;        /* The token itself */
+  Fts3Expr *pRoot;                /* Root of NEAR/AND cluster */
+  int nOvfl;                      /* Number of overflow pages to load doclist */
+  int iCol;                       /* The column the token must match */
+};
+
+/*
+** This function is used to populate an allocated Fts3TokenAndCost array.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, if an error occurs during execution, *pRc is set to an
+** SQLite error code.
+*/
+static void fts3EvalTokenCosts(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pRoot,                /* Root of current AND/NEAR cluster */
+  Fts3Expr *pExpr,                /* Expression to consider */
+  Fts3TokenAndCost **ppTC,        /* Write new entries to *(*ppTC)++ */
+  Fts3Expr ***ppOr,               /* Write new OR root to *(*ppOr)++ */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( *pRc==SQLITE_OK ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      Fts3Phrase *pPhrase = pExpr->pPhrase;
+      int i;
+      for(i=0; *pRc==SQLITE_OK && i<pPhrase->nToken; i++){
+        Fts3TokenAndCost *pTC = (*ppTC)++;
+        pTC->pPhrase = pPhrase;
+        pTC->iToken = i;
+        pTC->pRoot = pRoot;
+        pTC->pToken = &pPhrase->aToken[i];
+        pTC->iCol = pPhrase->iColumn;
+        *pRc = sqlite3Fts3MsrOvfl(pCsr, pTC->pToken->pSegcsr, &pTC->nOvfl);
+      }
+    }else if( pExpr->eType!=FTSQUERY_NOT ){
+      assert( pExpr->eType==FTSQUERY_OR
+           || pExpr->eType==FTSQUERY_AND
+           || pExpr->eType==FTSQUERY_NEAR
+      );
+      assert( pExpr->pLeft && pExpr->pRight );
+      if( pExpr->eType==FTSQUERY_OR ){
+        pRoot = pExpr->pLeft;
+        **ppOr = pRoot;
+        (*ppOr)++;
+      }
+      fts3EvalTokenCosts(pCsr, pRoot, pExpr->pLeft, ppTC, ppOr, pRc);
+      if( pExpr->eType==FTSQUERY_OR ){
+        pRoot = pExpr->pRight;
+        **ppOr = pRoot;
+        (*ppOr)++;
+      }
+      fts3EvalTokenCosts(pCsr, pRoot, pExpr->pRight, ppTC, ppOr, pRc);
+    }
+  }
+}
+
+/*
+** Determine the average document (row) size in pages. If successful,
+** write this value to *pnPage and return SQLITE_OK. Otherwise, return
+** an SQLite error code.
+**
+** The average document size in pages is calculated by first calculating
+** determining the average size in bytes, B. If B is less than the amount
+** of data that will fit on a single leaf page of an intkey table in
+** this database, then the average docsize is 1. Otherwise, it is 1 plus
+** the number of overflow pages consumed by a record B bytes in size.
+*/
+static int fts3EvalAverageDocsize(Fts3Cursor *pCsr, int *pnPage){
+  int rc = SQLITE_OK;
+  if( pCsr->nRowAvg==0 ){
+    /* The average document size, which is required to calculate the cost
+    ** of each doclist, has not yet been determined. Read the required
+    ** data from the %_stat table to calculate it.
+    **
+    ** Entry 0 of the %_stat table is a blob containing (nCol+1) FTS3
+    ** varints, where nCol is the number of columns in the FTS3 table.
+    ** The first varint is the number of documents currently stored in
+    ** the table. The following nCol varints contain the total amount of
+    ** data stored in all rows of each column of the table, from left
+    ** to right.
+    */
+    Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
+    sqlite3_stmt *pStmt;
+    sqlite3_int64 nDoc = 0;
+    sqlite3_int64 nByte = 0;
+    const char *pEnd;
+    const char *a;
+
+    rc = sqlite3Fts3SelectDoctotal(p, &pStmt);
+    if( rc!=SQLITE_OK ) return rc;
+    a = sqlite3_column_blob(pStmt, 0);
+    testcase( a==0 );  /* If %_stat.value set to X'' */
+    if( a ){
+      pEnd = &a[sqlite3_column_bytes(pStmt, 0)];
+      a += sqlite3Fts3GetVarintBounded(a, pEnd, &nDoc);
+      while( a<pEnd ){
+        a += sqlite3Fts3GetVarintBounded(a, pEnd, &nByte);
+      }
+    }
+    if( nDoc==0 || nByte==0 ){
+      sqlite3_reset(pStmt);
+      return FTS_CORRUPT_VTAB;
+    }
+
+    pCsr->nDoc = nDoc;
+    pCsr->nRowAvg = (int)(((nByte / nDoc) + p->nPgsz) / p->nPgsz);
+    assert( pCsr->nRowAvg>0 );
+    rc = sqlite3_reset(pStmt);
+  }
+
+  *pnPage = pCsr->nRowAvg;
+  return rc;
+}
+
+/*
+** This function is called to select the tokens (if any) that will be
+** deferred. The array aTC[] has already been populated when this is
+** called.
+**
+** This function is called once for each AND/NEAR cluster in the
+** expression. Each invocation determines which tokens to defer within
+** the cluster with root node pRoot. See comments above the definition
+** of struct Fts3TokenAndCost for more details.
+**
+** If no error occurs, SQLITE_OK is returned and sqlite3Fts3DeferToken()
+** called on each token to defer. Otherwise, an SQLite error code is
+** returned.
+*/
+static int fts3EvalSelectDeferred(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pRoot,                /* Consider tokens with this root node */
+  Fts3TokenAndCost *aTC,          /* Array of expression tokens and costs */
+  int nTC                         /* Number of entries in aTC[] */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int nDocSize = 0;               /* Number of pages per doc loaded */
+  int rc = SQLITE_OK;             /* Return code */
+  int ii;                         /* Iterator variable for various purposes */
+  int nOvfl = 0;                  /* Total overflow pages used by doclists */
+  int nToken = 0;                 /* Total number of tokens in cluster */
+
+  int nMinEst = 0;                /* The minimum count for any phrase so far. */
+  int nLoad4 = 1;                 /* (Phrases that will be loaded)^4. */
+
+  /* Tokens are never deferred for FTS tables created using the content=xxx
+  ** option. The reason being that it is not guaranteed that the content
+  ** table actually contains the same data as the index. To prevent this from
+  ** causing any problems, the deferred token optimization is completely
+  ** disabled for content=xxx tables. */
+  if( pTab->zContentTbl ){
+    return SQLITE_OK;
+  }
+
+  /* Count the tokens in this AND/NEAR cluster. If none of the doclists
+  ** associated with the tokens spill onto overflow pages, or if there is
+  ** only 1 token, exit early. No tokens to defer in this case. */
+  for(ii=0; ii<nTC; ii++){
+    if( aTC[ii].pRoot==pRoot ){
+      nOvfl += aTC[ii].nOvfl;
+      nToken++;
+    }
+  }
+  if( nOvfl==0 || nToken<2 ) return SQLITE_OK;
+
+  /* Obtain the average docsize (in pages). */
+  rc = fts3EvalAverageDocsize(pCsr, &nDocSize);
+  assert( rc!=SQLITE_OK || nDocSize>0 );
+
+
+  /* Iterate through all tokens in this AND/NEAR cluster, in ascending order
+  ** of the number of overflow pages that will be loaded by the pager layer
+  ** to retrieve the entire doclist for the token from the full-text index.
+  ** Load the doclists for tokens that are either:
+  **
+  **   a. The cheapest token in the entire query (i.e. the one visited by the
+  **      first iteration of this loop), or
+  **
+  **   b. Part of a multi-token phrase.
+  **
+  ** After each token doclist is loaded, merge it with the others from the
+  ** same phrase and count the number of documents that the merged doclist
+  ** contains. Set variable "nMinEst" to the smallest number of documents in
+  ** any phrase doclist for which 1 or more token doclists have been loaded.
+  ** Let nOther be the number of other phrases for which it is certain that
+  ** one or more tokens will not be deferred.
+  **
+  ** Then, for each token, defer it if loading the doclist would result in
+  ** loading N or more overflow pages into memory, where N is computed as:
+  **
+  **    (nMinEst + 4^nOther - 1) / (4^nOther)
+  */
+  for(ii=0; ii<nToken && rc==SQLITE_OK; ii++){
+    int iTC;                      /* Used to iterate through aTC[] array. */
+    Fts3TokenAndCost *pTC = 0;    /* Set to cheapest remaining token. */
+
+    /* Set pTC to point to the cheapest remaining token. */
+    for(iTC=0; iTC<nTC; iTC++){
+      if( aTC[iTC].pToken && aTC[iTC].pRoot==pRoot
+       && (!pTC || aTC[iTC].nOvfl<pTC->nOvfl)
+      ){
+        pTC = &aTC[iTC];
+      }
+    }
+    assert( pTC );
+
+    if( ii && pTC->nOvfl>=((nMinEst+(nLoad4/4)-1)/(nLoad4/4))*nDocSize ){
+      /* The number of overflow pages to load for this (and therefore all
+      ** subsequent) tokens is greater than the estimated number of pages
+      ** that will be loaded if all subsequent tokens are deferred.
+      */
+      Fts3PhraseToken *pToken = pTC->pToken;
+      rc = sqlite3Fts3DeferToken(pCsr, pToken, pTC->iCol);
+      fts3SegReaderCursorFree(pToken->pSegcsr);
+      pToken->pSegcsr = 0;
+    }else{
+      /* Set nLoad4 to the value of (4^nOther) for the next iteration of the
+      ** for-loop. Except, limit the value to 2^24 to prevent it from
+      ** overflowing the 32-bit integer it is stored in. */
+      if( ii<12 ) nLoad4 = nLoad4*4;
+
+      if( ii==0 || (pTC->pPhrase->nToken>1 && ii!=nToken-1) ){
+        /* Either this is the cheapest token in the entire query, or it is
+        ** part of a multi-token phrase. Either way, the entire doclist will
+        ** (eventually) be loaded into memory. It may as well be now. */
+        Fts3PhraseToken *pToken = pTC->pToken;
+        int nList = 0;
+        char *pList = 0;
+        rc = fts3TermSelect(pTab, pToken, pTC->iCol, &nList, &pList);
+        assert( rc==SQLITE_OK || pList==0 );
+        if( rc==SQLITE_OK ){
+          rc = fts3EvalPhraseMergeToken(
+              pTab, pTC->pPhrase, pTC->iToken,pList,nList
+          );
+        }
+        if( rc==SQLITE_OK ){
+          int nCount;
+          nCount = fts3DoclistCountDocids(
+              pTC->pPhrase->doclist.aAll, pTC->pPhrase->doclist.nAll
+          );
+          if( ii==0 || nCount<nMinEst ) nMinEst = nCount;
+        }
+      }
+    }
+    pTC->pToken = 0;
+  }
+
+  return rc;
+}
+
+/*
+** This function is called from within the xFilter method. It initializes
+** the full-text query currently stored in pCsr->pExpr. To iterate through
+** the results of a query, the caller does:
+**
+**    fts3EvalStart(pCsr);
+**    while( 1 ){
+**      fts3EvalNext(pCsr);
+**      if( pCsr->bEof ) break;
+**      ... return row pCsr->iPrevId to the caller ...
+**    }
+*/
+static int fts3EvalStart(Fts3Cursor *pCsr){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int nToken = 0;
+  int nOr = 0;
+
+  /* Allocate a MultiSegReader for each token in the expression. */
+  fts3EvalAllocateReaders(pCsr, pCsr->pExpr, &nToken, &nOr, &rc);
+
+  /* Determine which, if any, tokens in the expression should be deferred. */
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+  if( rc==SQLITE_OK && nToken>1 && pTab->bFts4 ){
+    Fts3TokenAndCost *aTC;
+    aTC = (Fts3TokenAndCost *)sqlite3_malloc64(
+        sizeof(Fts3TokenAndCost) * nToken
+      + sizeof(Fts3Expr *) * nOr * 2
+    );
+
+    if( !aTC ){
+      rc = SQLITE_NOMEM;
+    }else{
+      Fts3Expr **apOr = (Fts3Expr **)&aTC[nToken];
+      int ii;
+      Fts3TokenAndCost *pTC = aTC;
+      Fts3Expr **ppOr = apOr;
+
+      fts3EvalTokenCosts(pCsr, 0, pCsr->pExpr, &pTC, &ppOr, &rc);
+      nToken = (int)(pTC-aTC);
+      nOr = (int)(ppOr-apOr);
+
+      if( rc==SQLITE_OK ){
+        rc = fts3EvalSelectDeferred(pCsr, 0, aTC, nToken);
+        for(ii=0; rc==SQLITE_OK && ii<nOr; ii++){
+          rc = fts3EvalSelectDeferred(pCsr, apOr[ii], aTC, nToken);
+        }
+      }
+
+      sqlite3_free(aTC);
+    }
+  }
+#endif
+
+  fts3EvalStartReaders(pCsr, pCsr->pExpr, &rc);
+  return rc;
+}
+
+/*
+** Invalidate the current position list for phrase pPhrase.
+*/
+static void fts3EvalInvalidatePoslist(Fts3Phrase *pPhrase){
+  if( pPhrase->doclist.bFreeList ){
+    sqlite3_free(pPhrase->doclist.pList);
+  }
+  pPhrase->doclist.pList = 0;
+  pPhrase->doclist.nList = 0;
+  pPhrase->doclist.bFreeList = 0;
+}
+
+/*
+** This function is called to edit the position list associated with
+** the phrase object passed as the fifth argument according to a NEAR
+** condition. For example:
+**
+**     abc NEAR/5 "def ghi"
+**
+** Parameter nNear is passed the NEAR distance of the expression (5 in
+** the example above). When this function is called, *paPoslist points to
+** the position list, and *pnToken is the number of phrase tokens in the
+** phrase on the other side of the NEAR operator to pPhrase. For example,
+** if pPhrase refers to the "def ghi" phrase, then *paPoslist points to
+** the position list associated with phrase "abc".
+**
+** All positions in the pPhrase position list that are not sufficiently
+** close to a position in the *paPoslist position list are removed. If this
+** leaves 0 positions, zero is returned. Otherwise, non-zero.
+**
+** Before returning, *paPoslist is set to point to the position lsit
+** associated with pPhrase. And *pnToken is set to the number of tokens in
+** pPhrase.
+*/
+static int fts3EvalNearTrim(
+  int nNear,                      /* NEAR distance. As in "NEAR/nNear". */
+  char *aTmp,                     /* Temporary space to use */
+  char **paPoslist,               /* IN/OUT: Position list */
+  int *pnToken,                   /* IN/OUT: Tokens in phrase of *paPoslist */
+  Fts3Phrase *pPhrase             /* The phrase object to trim the doclist of */
+){
+  int nParam1 = nNear + pPhrase->nToken;
+  int nParam2 = nNear + *pnToken;
+  int nNew;
+  char *p2;
+  char *pOut;
+  int res;
+
+  assert( pPhrase->doclist.pList );
+
+  p2 = pOut = pPhrase->doclist.pList;
+  res = fts3PoslistNearMerge(
+    &pOut, aTmp, nParam1, nParam2, paPoslist, &p2
+  );
+  if( res ){
+    nNew = (int)(pOut - pPhrase->doclist.pList) - 1;
+    assert_fts3_nc( nNew<=pPhrase->doclist.nList && nNew>0 );
+    if( nNew>=0 && nNew<=pPhrase->doclist.nList ){
+      assert( pPhrase->doclist.pList[nNew]=='\0' );
+      memset(&pPhrase->doclist.pList[nNew], 0, pPhrase->doclist.nList - nNew);
+      pPhrase->doclist.nList = nNew;
+    }
+    *paPoslist = pPhrase->doclist.pList;
+    *pnToken = pPhrase->nToken;
+  }
+
+  return res;
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is called.
+** Otherwise, it advances the expression passed as the second argument to
+** point to the next matching row in the database. Expressions iterate through
+** matching rows in docid order. Ascending order if Fts3Cursor.bDesc is zero,
+** or descending if it is non-zero.
+**
+** If an error occurs, *pRc is set to an SQLite error code. Otherwise, if
+** successful, the following variables in pExpr are set:
+**
+**   Fts3Expr.bEof                (non-zero if EOF - there is no next row)
+**   Fts3Expr.iDocid              (valid if bEof==0. The docid of the next row)
+**
+** If the expression is of type FTSQUERY_PHRASE, and the expression is not
+** at EOF, then the following variables are populated with the position list
+** for the phrase for the visited row:
+**
+**   FTs3Expr.pPhrase->doclist.nList        (length of pList in bytes)
+**   FTs3Expr.pPhrase->doclist.pList        (pointer to position list)
+**
+** It says above that this function advances the expression to the next
+** matching row. This is usually true, but there are the following exceptions:
+**
+**   1. Deferred tokens are not taken into account. If a phrase consists
+**      entirely of deferred tokens, it is assumed to match every row in
+**      the db. In this case the position-list is not populated at all.
+**
+**      Or, if a phrase contains one or more deferred tokens and one or
+**      more non-deferred tokens, then the expression is advanced to the
+**      next possible match, considering only non-deferred tokens. In other
+**      words, if the phrase is "A B C", and "B" is deferred, the expression
+**      is advanced to the next row that contains an instance of "A * C",
+**      where "*" may match any single token. The position list in this case
+**      is populated as for "A * C" before returning.
+**
+**   2. NEAR is treated as AND. If the expression is "x NEAR y", it is
+**      advanced to point to the next row that matches "x AND y".
+**
+** See sqlite3Fts3EvalTestDeferred() for details on testing if a row is
+** really a match, taking into account deferred tokens and NEAR operators.
+*/
+static void fts3EvalNextRow(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pExpr,                /* Expr. to advance to next matching row */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( *pRc==SQLITE_OK && pExpr->bEof==0 ){
+    int bDescDoclist = pCsr->bDesc;         /* Used by DOCID_CMP() macro */
+    pExpr->bStart = 1;
+
+    switch( pExpr->eType ){
+      case FTSQUERY_NEAR:
+      case FTSQUERY_AND: {
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+        assert( !pLeft->bDeferred || !pRight->bDeferred );
+
+        if( pLeft->bDeferred ){
+          /* LHS is entirely deferred. So we assume it matches every row.
+          ** Advance the RHS iterator to find the next row visited. */
+          fts3EvalNextRow(pCsr, pRight, pRc);
+          pExpr->iDocid = pRight->iDocid;
+          pExpr->bEof = pRight->bEof;
+        }else if( pRight->bDeferred ){
+          /* RHS is entirely deferred. So we assume it matches every row.
+          ** Advance the LHS iterator to find the next row visited. */
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+          pExpr->iDocid = pLeft->iDocid;
+          pExpr->bEof = pLeft->bEof;
+        }else{
+          /* Neither the RHS or LHS are deferred. */
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+          fts3EvalNextRow(pCsr, pRight, pRc);
+          while( !pLeft->bEof && !pRight->bEof && *pRc==SQLITE_OK ){
+            sqlite3_int64 iDiff = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
+            if( iDiff==0 ) break;
+            if( iDiff<0 ){
+              fts3EvalNextRow(pCsr, pLeft, pRc);
+            }else{
+              fts3EvalNextRow(pCsr, pRight, pRc);
+            }
+          }
+          pExpr->iDocid = pLeft->iDocid;
+          pExpr->bEof = (pLeft->bEof || pRight->bEof);
+          if( pExpr->eType==FTSQUERY_NEAR && pExpr->bEof ){
+            assert( pRight->eType==FTSQUERY_PHRASE );
+            if( pRight->pPhrase->doclist.aAll ){
+              Fts3Doclist *pDl = &pRight->pPhrase->doclist;
+              while( *pRc==SQLITE_OK && pRight->bEof==0 ){
+                memset(pDl->pList, 0, pDl->nList);
+                fts3EvalNextRow(pCsr, pRight, pRc);
+              }
+            }
+            if( pLeft->pPhrase && pLeft->pPhrase->doclist.aAll ){
+              Fts3Doclist *pDl = &pLeft->pPhrase->doclist;
+              while( *pRc==SQLITE_OK && pLeft->bEof==0 ){
+                memset(pDl->pList, 0, pDl->nList);
+                fts3EvalNextRow(pCsr, pLeft, pRc);
+              }
+            }
+            pRight->bEof = pLeft->bEof = 1;
+          }
+        }
+        break;
+      }
+
+      case FTSQUERY_OR: {
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+        sqlite3_int64 iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
+
+        assert_fts3_nc( pLeft->bStart || pLeft->iDocid==pRight->iDocid );
+        assert_fts3_nc( pRight->bStart || pLeft->iDocid==pRight->iDocid );
+
+        if( pRight->bEof || (pLeft->bEof==0 && iCmp<0) ){
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+        }else if( pLeft->bEof || iCmp>0 ){
+          fts3EvalNextRow(pCsr, pRight, pRc);
+        }else{
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+          fts3EvalNextRow(pCsr, pRight, pRc);
+        }
+
+        pExpr->bEof = (pLeft->bEof && pRight->bEof);
+        iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
+        if( pRight->bEof || (pLeft->bEof==0 &&  iCmp<0) ){
+          pExpr->iDocid = pLeft->iDocid;
+        }else{
+          pExpr->iDocid = pRight->iDocid;
+        }
+
+        break;
+      }
+
+      case FTSQUERY_NOT: {
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+
+        if( pRight->bStart==0 ){
+          fts3EvalNextRow(pCsr, pRight, pRc);
+          assert( *pRc!=SQLITE_OK || pRight->bStart );
+        }
+
+        fts3EvalNextRow(pCsr, pLeft, pRc);
+        if( pLeft->bEof==0 ){
+          while( !*pRc
+              && !pRight->bEof
+              && DOCID_CMP(pLeft->iDocid, pRight->iDocid)>0
+          ){
+            fts3EvalNextRow(pCsr, pRight, pRc);
+          }
+        }
+        pExpr->iDocid = pLeft->iDocid;
+        pExpr->bEof = pLeft->bEof;
+        break;
+      }
+
+      default: {
+        Fts3Phrase *pPhrase = pExpr->pPhrase;
+        fts3EvalInvalidatePoslist(pPhrase);
+        *pRc = fts3EvalPhraseNext(pCsr, pPhrase, &pExpr->bEof);
+        pExpr->iDocid = pPhrase->doclist.iDocid;
+        break;
+      }
+    }
+  }
+}
+
+/*
+** If *pRc is not SQLITE_OK, or if pExpr is not the root node of a NEAR
+** cluster, then this function returns 1 immediately.
+**
+** Otherwise, it checks if the current row really does match the NEAR
+** expression, using the data currently stored in the position lists
+** (Fts3Expr->pPhrase.doclist.pList/nList) for each phrase in the expression.
+**
+** If the current row is a match, the position list associated with each
+** phrase in the NEAR expression is edited in place to contain only those
+** phrase instances sufficiently close to their peers to satisfy all NEAR
+** constraints. In this case it returns 1. If the NEAR expression does not
+** match the current row, 0 is returned. The position lists may or may not
+** be edited if 0 is returned.
+*/
+static int fts3EvalNearTest(Fts3Expr *pExpr, int *pRc){
+  int res = 1;
+
+  /* The following block runs if pExpr is the root of a NEAR query.
+  ** For example, the query:
+  **
+  **         "w" NEAR "x" NEAR "y" NEAR "z"
+  **
+  ** which is represented in tree form as:
+  **
+  **                               |
+  **                          +--NEAR--+      <-- root of NEAR query
+  **                          |        |
+  **                     +--NEAR--+   "z"
+  **                     |        |
+  **                +--NEAR--+   "y"
+  **                |        |
+  **               "w"      "x"
+  **
+  ** The right-hand child of a NEAR node is always a phrase. The
+  ** left-hand child may be either a phrase or a NEAR node. There are
+  ** no exceptions to this - it's the way the parser in fts3_expr.c works.
+  */
+  if( *pRc==SQLITE_OK
+   && pExpr->eType==FTSQUERY_NEAR
+   && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
+  ){
+    Fts3Expr *p;
+    sqlite3_int64 nTmp = 0;       /* Bytes of temp space */
+    char *aTmp;                   /* Temp space for PoslistNearMerge() */
+
+    /* Allocate temporary working space. */
+    for(p=pExpr; p->pLeft; p=p->pLeft){
+      assert( p->pRight->pPhrase->doclist.nList>0 );
+      nTmp += p->pRight->pPhrase->doclist.nList;
+    }
+    nTmp += p->pPhrase->doclist.nList;
+    aTmp = sqlite3_malloc64(nTmp*2 + FTS3_VARINT_MAX);
+    if( !aTmp ){
+      *pRc = SQLITE_NOMEM;
+      res = 0;
+    }else{
+      char *aPoslist = p->pPhrase->doclist.pList;
+      int nToken = p->pPhrase->nToken;
+
+      for(p=p->pParent;res && p && p->eType==FTSQUERY_NEAR; p=p->pParent){
+        Fts3Phrase *pPhrase = p->pRight->pPhrase;
+        int nNear = p->nNear;
+        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
+      }
+
+      aPoslist = pExpr->pRight->pPhrase->doclist.pList;
+      nToken = pExpr->pRight->pPhrase->nToken;
+      for(p=pExpr->pLeft; p && res; p=p->pLeft){
+        int nNear;
+        Fts3Phrase *pPhrase;
+        assert( p->pParent && p->pParent->pLeft==p );
+        nNear = p->pParent->nNear;
+        pPhrase = (
+            p->eType==FTSQUERY_NEAR ? p->pRight->pPhrase : p->pPhrase
+        );
+        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
+      }
+    }
+
+    sqlite3_free(aTmp);
+  }
+
+  return res;
+}
+
+/*
+** This function is a helper function for sqlite3Fts3EvalTestDeferred().
+** Assuming no error occurs or has occurred, It returns non-zero if the
+** expression passed as the second argument matches the row that pCsr
+** currently points to, or zero if it does not.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** If an error occurs during execution of this function, *pRc is set to
+** the appropriate SQLite error code. In this case the returned value is
+** undefined.
+*/
+static int fts3EvalTestExpr(
+  Fts3Cursor *pCsr,               /* FTS cursor handle */
+  Fts3Expr *pExpr,                /* Expr to test. May or may not be root. */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  int bHit = 1;                   /* Return value */
+  if( *pRc==SQLITE_OK ){
+    switch( pExpr->eType ){
+      case FTSQUERY_NEAR:
+      case FTSQUERY_AND:
+        bHit = (
+            fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc)
+         && fts3EvalTestExpr(pCsr, pExpr->pRight, pRc)
+         && fts3EvalNearTest(pExpr, pRc)
+        );
+
+        /* If the NEAR expression does not match any rows, zero the doclist for
+        ** all phrases involved in the NEAR. This is because the snippet(),
+        ** offsets() and matchinfo() functions are not supposed to recognize
+        ** any instances of phrases that are part of unmatched NEAR queries.
+        ** For example if this expression:
+        **
+        **    ... MATCH 'a OR (b NEAR c)'
+        **
+        ** is matched against a row containing:
+        **
+        **        'a b d e'
+        **
+        ** then any snippet() should ony highlight the "a" term, not the "b"
+        ** (as "b" is part of a non-matching NEAR clause).
+        */
+        if( bHit==0
+         && pExpr->eType==FTSQUERY_NEAR
+         && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
+        ){
+          Fts3Expr *p;
+          for(p=pExpr; p->pPhrase==0; p=p->pLeft){
+            if( p->pRight->iDocid==pCsr->iPrevId ){
+              fts3EvalInvalidatePoslist(p->pRight->pPhrase);
+            }
+          }
+          if( p->iDocid==pCsr->iPrevId ){
+            fts3EvalInvalidatePoslist(p->pPhrase);
+          }
+        }
+
+        break;
+
+      case FTSQUERY_OR: {
+        int bHit1 = fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc);
+        int bHit2 = fts3EvalTestExpr(pCsr, pExpr->pRight, pRc);
+        bHit = bHit1 || bHit2;
+        break;
+      }
+
+      case FTSQUERY_NOT:
+        bHit = (
+            fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc)
+         && !fts3EvalTestExpr(pCsr, pExpr->pRight, pRc)
+        );
+        break;
+
+      default: {
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+        if( pCsr->pDeferred && (pExpr->bDeferred || (
+            pExpr->iDocid==pCsr->iPrevId && pExpr->pPhrase->doclist.pList
+        ))){
+          Fts3Phrase *pPhrase = pExpr->pPhrase;
+          if( pExpr->bDeferred ){
+            fts3EvalInvalidatePoslist(pPhrase);
+          }
+          *pRc = fts3EvalDeferredPhrase(pCsr, pPhrase);
+          bHit = (pPhrase->doclist.pList!=0);
+          pExpr->iDocid = pCsr->iPrevId;
+        }else
+#endif
+        {
+          bHit = (
+              pExpr->bEof==0 && pExpr->iDocid==pCsr->iPrevId
+           && pExpr->pPhrase->doclist.nList>0
+          );
+        }
+        break;
+      }
+    }
+  }
+  return bHit;
+}
+
+/*
+** This function is called as the second part of each xNext operation when
+** iterating through the results of a full-text query. At this point the
+** cursor points to a row that matches the query expression, with the
+** following caveats:
+**
+**   * Up until this point, "NEAR" operators in the expression have been
+**     treated as "AND".
+**
+**   * Deferred tokens have not yet been considered.
+**
+** If *pRc is not SQLITE_OK when this function is called, it immediately
+** returns 0. Otherwise, it tests whether or not after considering NEAR
+** operators and deferred tokens the current row is still a match for the
+** expression. It returns 1 if both of the following are true:
+**
+**   1. *pRc is SQLITE_OK when this function returns, and
+**
+**   2. After scanning the current FTS table row for the deferred tokens,
+**      it is determined that the row does *not* match the query.
+**
+** Or, if no error occurs and it seems the current row does match the FTS
+** query, return 0.
+*/
+SQLITE_PRIVATE int sqlite3Fts3EvalTestDeferred(Fts3Cursor *pCsr, int *pRc){
+  int rc = *pRc;
+  int bMiss = 0;
+  if( rc==SQLITE_OK ){
+
+    /* If there are one or more deferred tokens, load the current row into
+    ** memory and scan it to determine the position list for each deferred
+    ** token. Then, see if this row is really a match, considering deferred
+    ** tokens and NEAR operators (neither of which were taken into account
+    ** earlier, by fts3EvalNextRow()).
+    */
+    if( pCsr->pDeferred ){
+      rc = fts3CursorSeek(0, pCsr);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3Fts3CacheDeferredDoclists(pCsr);
+      }
+    }
+    bMiss = (0==fts3EvalTestExpr(pCsr, pCsr->pExpr, &rc));
+
+    /* Free the position-lists accumulated for each deferred token above. */
+    sqlite3Fts3FreeDeferredDoclists(pCsr);
+    *pRc = rc;
+  }
+  return (rc==SQLITE_OK && bMiss);
+}
+
+/*
+** Advance to the next document that matches the FTS expression in
+** Fts3Cursor.pExpr.
+*/
+static int fts3EvalNext(Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;             /* Return Code */
+  Fts3Expr *pExpr = pCsr->pExpr;
+  assert( pCsr->isEof==0 );
+  if( pExpr==0 ){
+    pCsr->isEof = 1;
+  }else{
+    do {
+      if( pCsr->isRequireSeek==0 ){
+        sqlite3_reset(pCsr->pStmt);
+      }
+      assert( sqlite3_data_count(pCsr->pStmt)==0 );
+      fts3EvalNextRow(pCsr, pExpr, &rc);
+      pCsr->isEof = pExpr->bEof;
+      pCsr->isRequireSeek = 1;
+      pCsr->isMatchinfoNeeded = 1;
+      pCsr->iPrevId = pExpr->iDocid;
+    }while( pCsr->isEof==0 && sqlite3Fts3EvalTestDeferred(pCsr, &rc) );
+  }
+
+  /* Check if the cursor is past the end of the docid range specified
+  ** by Fts3Cursor.iMinDocid/iMaxDocid. If so, set the EOF flag.  */
+  if( rc==SQLITE_OK && (
+        (pCsr->bDesc==0 && pCsr->iPrevId>pCsr->iMaxDocid)
+     || (pCsr->bDesc!=0 && pCsr->iPrevId<pCsr->iMinDocid)
+  )){
+    pCsr->isEof = 1;
+  }
+
+  return rc;
+}
+
+/*
+** Restart interation for expression pExpr so that the next call to
+** fts3EvalNext() visits the first row. Do not allow incremental
+** loading or merging of phrase doclists for this iteration.
+**
+** If *pRc is other than SQLITE_OK when this function is called, it is
+** a no-op. If an error occurs within this function, *pRc is set to an
+** SQLite error code before returning.
+*/
+static void fts3EvalRestart(
+  Fts3Cursor *pCsr,
+  Fts3Expr *pExpr,
+  int *pRc
+){
+  if( pExpr && *pRc==SQLITE_OK ){
+    Fts3Phrase *pPhrase = pExpr->pPhrase;
+
+    if( pPhrase ){
+      fts3EvalInvalidatePoslist(pPhrase);
+      if( pPhrase->bIncr ){
+        int i;
+        for(i=0; i<pPhrase->nToken; i++){
+          Fts3PhraseToken *pToken = &pPhrase->aToken[i];
+          assert( pToken->pDeferred==0 );
+          if( pToken->pSegcsr ){
+            sqlite3Fts3MsrIncrRestart(pToken->pSegcsr);
+          }
+        }
+        *pRc = fts3EvalPhraseStart(pCsr, 0, pPhrase);
+      }
+      pPhrase->doclist.pNextDocid = 0;
+      pPhrase->doclist.iDocid = 0;
+      pPhrase->pOrPoslist = 0;
+    }
+
+    pExpr->iDocid = 0;
+    pExpr->bEof = 0;
+    pExpr->bStart = 0;
+
+    fts3EvalRestart(pCsr, pExpr->pLeft, pRc);
+    fts3EvalRestart(pCsr, pExpr->pRight, pRc);
+  }
+}
+
+/*
+** Expression node pExpr is an MSR phrase. This function restarts pExpr
+** so that it is a regular phrase query, not an MSR. SQLITE_OK is returned
+** if successful, or an SQLite error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3Fts3MsrCancel(Fts3Cursor *pCsr, Fts3Expr *pExpr){
+  int rc = SQLITE_OK;
+  if( pExpr->bEof==0 ){
+    i64 iDocid = pExpr->iDocid;
+    fts3EvalRestart(pCsr, pExpr, &rc);
+    while( rc==SQLITE_OK && pExpr->iDocid!=iDocid ){
+      fts3EvalNextRow(pCsr, pExpr, &rc);
+      if( pExpr->bEof ) rc = FTS_CORRUPT_VTAB;
+    }
+  }
+  return rc;
+}
+
+/*
+** After allocating the Fts3Expr.aMI[] array for each phrase in the
+** expression rooted at pExpr, the cursor iterates through all rows matched
+** by pExpr, calling this function for each row. This function increments
+** the values in Fts3Expr.aMI[] according to the position-list currently
+** found in Fts3Expr.pPhrase->doclist.pList for each of the phrase
+** expression nodes.
+*/
+static void fts3EvalUpdateCounts(Fts3Expr *pExpr, int nCol){
+  if( pExpr ){
+    Fts3Phrase *pPhrase = pExpr->pPhrase;
+    if( pPhrase && pPhrase->doclist.pList ){
+      int iCol = 0;
+      char *p = pPhrase->doclist.pList;
+
+      do{
+        u8 c = 0;
+        int iCnt = 0;
+        while( 0xFE & (*p | c) ){
+          if( (c&0x80)==0 ) iCnt++;
+          c = *p++ & 0x80;
+        }
+
+        /* aMI[iCol*3 + 1] = Number of occurrences
+        ** aMI[iCol*3 + 2] = Number of rows containing at least one instance
+        */
+        pExpr->aMI[iCol*3 + 1] += iCnt;
+        pExpr->aMI[iCol*3 + 2] += (iCnt>0);
+        if( *p==0x00 ) break;
+        p++;
+        p += fts3GetVarint32(p, &iCol);
+      }while( iCol<nCol );
+    }
+
+    fts3EvalUpdateCounts(pExpr->pLeft, nCol);
+    fts3EvalUpdateCounts(pExpr->pRight, nCol);
+  }
+}
+
+/*
+** This is an sqlite3Fts3ExprIterate() callback. If the Fts3Expr.aMI[] array
+** has not yet been allocated, allocate and zero it. Otherwise, just zero
+** it.
+*/
+static int fts3AllocateMSI(Fts3Expr *pExpr, int iPhrase, void *pCtx){
+  Fts3Table *pTab = (Fts3Table*)pCtx;
+  UNUSED_PARAMETER(iPhrase);
+  if( pExpr->aMI==0 ){
+    pExpr->aMI = (u32 *)sqlite3_malloc64(pTab->nColumn * 3 * sizeof(u32));
+    if( pExpr->aMI==0 ) return SQLITE_NOMEM;
+  }
+  memset(pExpr->aMI, 0, pTab->nColumn * 3 * sizeof(u32));
+  return SQLITE_OK;
+}
+
+/*
+** Expression pExpr must be of type FTSQUERY_PHRASE.
+**
+** If it is not already allocated and populated, this function allocates and
+** populates the Fts3Expr.aMI[] array for expression pExpr. If pExpr is part
+** of a NEAR expression, then it also allocates and populates the same array
+** for all other phrases that are part of the NEAR expression.
+**
+** SQLITE_OK is returned if the aMI[] array is successfully allocated and
+** populated. Otherwise, if an error occurs, an SQLite error code is returned.
+*/
+static int fts3EvalGatherStats(
+  Fts3Cursor *pCsr,               /* Cursor object */
+  Fts3Expr *pExpr                 /* FTSQUERY_PHRASE expression */
+){
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( pExpr->eType==FTSQUERY_PHRASE );
+  if( pExpr->aMI==0 ){
+    Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+    Fts3Expr *pRoot;                /* Root of NEAR expression */
+
+    sqlite3_int64 iPrevId = pCsr->iPrevId;
+    sqlite3_int64 iDocid;
+    u8 bEof;
+
+    /* Find the root of the NEAR expression */
+    pRoot = pExpr;
+    while( pRoot->pParent
+        && (pRoot->pParent->eType==FTSQUERY_NEAR || pRoot->bDeferred)
+    ){
+      pRoot = pRoot->pParent;
+    }
+    iDocid = pRoot->iDocid;
+    bEof = pRoot->bEof;
+    assert( pRoot->bStart );
+
+    /* Allocate space for the aMSI[] array of each FTSQUERY_PHRASE node */
+    rc = sqlite3Fts3ExprIterate(pRoot, fts3AllocateMSI, (void*)pTab);
+    if( rc!=SQLITE_OK ) return rc;
+    fts3EvalRestart(pCsr, pRoot, &rc);
+
+    while( pCsr->isEof==0 && rc==SQLITE_OK ){
+
+      do {
+        /* Ensure the %_content statement is reset. */
+        if( pCsr->isRequireSeek==0 ) sqlite3_reset(pCsr->pStmt);
+        assert( sqlite3_data_count(pCsr->pStmt)==0 );
+
+        /* Advance to the next document */
+        fts3EvalNextRow(pCsr, pRoot, &rc);
+        pCsr->isEof = pRoot->bEof;
+        pCsr->isRequireSeek = 1;
+        pCsr->isMatchinfoNeeded = 1;
+        pCsr->iPrevId = pRoot->iDocid;
+      }while( pCsr->isEof==0
+           && pRoot->eType==FTSQUERY_NEAR
+           && sqlite3Fts3EvalTestDeferred(pCsr, &rc)
+      );
+
+      if( rc==SQLITE_OK && pCsr->isEof==0 ){
+        fts3EvalUpdateCounts(pRoot, pTab->nColumn);
+      }
+    }
+
+    pCsr->isEof = 0;
+    pCsr->iPrevId = iPrevId;
+
+    if( bEof ){
+      pRoot->bEof = bEof;
+    }else{
+      /* Caution: pRoot may iterate through docids in ascending or descending
+      ** order. For this reason, even though it seems more defensive, the
+      ** do loop can not be written:
+      **
+      **   do {...} while( pRoot->iDocid<iDocid && rc==SQLITE_OK );
+      */
+      fts3EvalRestart(pCsr, pRoot, &rc);
+      do {
+        fts3EvalNextRow(pCsr, pRoot, &rc);
+        assert_fts3_nc( pRoot->bEof==0 );
+        if( pRoot->bEof ) rc = FTS_CORRUPT_VTAB;
+      }while( pRoot->iDocid!=iDocid && rc==SQLITE_OK );
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is used by the matchinfo() module to query a phrase
+** expression node for the following information:
+**
+**   1. The total number of occurrences of the phrase in each column of
+**      the FTS table (considering all rows), and
+**
+**   2. For each column, the number of rows in the table for which the
+**      column contains at least one instance of the phrase.
+**
+** If no error occurs, SQLITE_OK is returned and the values for each column
+** written into the array aiOut as follows:
+**
+**   aiOut[iCol*3 + 1] = Number of occurrences
+**   aiOut[iCol*3 + 2] = Number of rows containing at least one instance
+**
+** Caveats:
+**
+**   * If a phrase consists entirely of deferred tokens, then all output
+**     values are set to the number of documents in the table. In other
+**     words we assume that very common tokens occur exactly once in each
+**     column of each row of the table.
+**
+**   * If a phrase contains some deferred tokens (and some non-deferred
+**     tokens), count the potential occurrence identified by considering
+**     the non-deferred tokens instead of actual phrase occurrences.
+**
+**   * If the phrase is part of a NEAR expression, then only phrase instances
+**     that meet the NEAR constraint are included in the counts.
+*/
+SQLITE_PRIVATE int sqlite3Fts3EvalPhraseStats(
+  Fts3Cursor *pCsr,               /* FTS cursor handle */
+  Fts3Expr *pExpr,                /* Phrase expression */
+  u32 *aiOut                      /* Array to write results into (see above) */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int iCol;
+
+  if( pExpr->bDeferred && pExpr->pParent->eType!=FTSQUERY_NEAR ){
+    assert( pCsr->nDoc>0 );
+    for(iCol=0; iCol<pTab->nColumn; iCol++){
+      aiOut[iCol*3 + 1] = (u32)pCsr->nDoc;
+      aiOut[iCol*3 + 2] = (u32)pCsr->nDoc;
+    }
+  }else{
+    rc = fts3EvalGatherStats(pCsr, pExpr);
+    if( rc==SQLITE_OK ){
+      assert( pExpr->aMI );
+      for(iCol=0; iCol<pTab->nColumn; iCol++){
+        aiOut[iCol*3 + 1] = pExpr->aMI[iCol*3 + 1];
+        aiOut[iCol*3 + 2] = pExpr->aMI[iCol*3 + 2];
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The expression pExpr passed as the second argument to this function
+** must be of type FTSQUERY_PHRASE.
+**
+** The returned value is either NULL or a pointer to a buffer containing
+** a position-list indicating the occurrences of the phrase in column iCol
+** of the current row.
+**
+** More specifically, the returned buffer contains 1 varint for each
+** occurrence of the phrase in the column, stored using the normal (delta+2)
+** compression and is terminated by either an 0x01 or 0x00 byte. For example,
+** if the requested column contains "a b X c d X X" and the position-list
+** for 'X' is requested, the buffer returned may contain:
+**
+**     0x04 0x05 0x03 0x01   or   0x04 0x05 0x03 0x00
+**
+** This function works regardless of whether or not the phrase is deferred,
+** incremental, or neither.
+*/
+SQLITE_PRIVATE int sqlite3Fts3EvalPhrasePoslist(
+  Fts3Cursor *pCsr,               /* FTS3 cursor object */
+  Fts3Expr *pExpr,                /* Phrase to return doclist for */
+  int iCol,                       /* Column to return position list for */
+  char **ppOut                    /* OUT: Pointer to position list */
+){
+  Fts3Phrase *pPhrase = pExpr->pPhrase;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  char *pIter;
+  int iThis;
+  sqlite3_int64 iDocid;
+
+  /* If this phrase is applies specifically to some column other than
+  ** column iCol, return a NULL pointer.  */
+  *ppOut = 0;
+  assert( iCol>=0 && iCol<pTab->nColumn );
+  if( (pPhrase->iColumn<pTab->nColumn && pPhrase->iColumn!=iCol) ){
+    return SQLITE_OK;
+  }
+
+  iDocid = pExpr->iDocid;
+  pIter = pPhrase->doclist.pList;
+  if( iDocid!=pCsr->iPrevId || pExpr->bEof ){
+    int rc = SQLITE_OK;
+    int bDescDoclist = pTab->bDescIdx;      /* For DOCID_CMP macro */
+    int bOr = 0;
+    u8 bTreeEof = 0;
+    Fts3Expr *p;                  /* Used to iterate from pExpr to root */
+    Fts3Expr *pNear;              /* Most senior NEAR ancestor (or pExpr) */
+    Fts3Expr *pRun;               /* Closest non-deferred ancestor of pNear */
+    int bMatch;
+
+    /* Check if this phrase descends from an OR expression node. If not,
+    ** return NULL. Otherwise, the entry that corresponds to docid
+    ** pCsr->iPrevId may lie earlier in the doclist buffer. Or, if the
+    ** tree that the node is part of has been marked as EOF, but the node
+    ** itself is not EOF, then it may point to an earlier entry. */
+    pNear = pExpr;
+    for(p=pExpr->pParent; p; p=p->pParent){
+      if( p->eType==FTSQUERY_OR ) bOr = 1;
+      if( p->eType==FTSQUERY_NEAR ) pNear = p;
+      if( p->bEof ) bTreeEof = 1;
+    }
+    if( bOr==0 ) return SQLITE_OK;
+    pRun = pNear;
+    while( pRun->bDeferred ){
+      assert( pRun->pParent );
+      pRun = pRun->pParent;
+    }
+
+    /* This is the descendent of an OR node. In this case we cannot use
+    ** an incremental phrase. Load the entire doclist for the phrase
+    ** into memory in this case.  */
+    if( pPhrase->bIncr ){
+      int bEofSave = pRun->bEof;
+      fts3EvalRestart(pCsr, pRun, &rc);
+      while( rc==SQLITE_OK && !pRun->bEof ){
+        fts3EvalNextRow(pCsr, pRun, &rc);
+        if( bEofSave==0 && pRun->iDocid==iDocid ) break;
+      }
+      assert( rc!=SQLITE_OK || pPhrase->bIncr==0 );
+      if( rc==SQLITE_OK && pRun->bEof!=bEofSave ){
+        rc = FTS_CORRUPT_VTAB;
+      }
+    }
+    if( bTreeEof ){
+      while( rc==SQLITE_OK && !pRun->bEof ){
+        fts3EvalNextRow(pCsr, pRun, &rc);
+      }
+    }
+    if( rc!=SQLITE_OK ) return rc;
+
+    bMatch = 1;
+    for(p=pNear; p; p=p->pLeft){
+      u8 bEof = 0;
+      Fts3Expr *pTest = p;
+      Fts3Phrase *pPh;
+      assert( pTest->eType==FTSQUERY_NEAR || pTest->eType==FTSQUERY_PHRASE );
+      if( pTest->eType==FTSQUERY_NEAR ) pTest = pTest->pRight;
+      assert( pTest->eType==FTSQUERY_PHRASE );
+      pPh = pTest->pPhrase;
+
+      pIter = pPh->pOrPoslist;
+      iDocid = pPh->iOrDocid;
+      if( pCsr->bDesc==bDescDoclist ){
+        bEof = !pPh->doclist.nAll ||
+          (pIter >= (pPh->doclist.aAll + pPh->doclist.nAll));
+        while( (pIter==0 || DOCID_CMP(iDocid, pCsr->iPrevId)<0 ) && bEof==0 ){
+          sqlite3Fts3DoclistNext(
+              bDescDoclist, pPh->doclist.aAll, pPh->doclist.nAll,
+              &pIter, &iDocid, &bEof
+          );
+        }
+      }else{
+        bEof = !pPh->doclist.nAll || (pIter && pIter<=pPh->doclist.aAll);
+        while( (pIter==0 || DOCID_CMP(iDocid, pCsr->iPrevId)>0 ) && bEof==0 ){
+          int dummy;
+          sqlite3Fts3DoclistPrev(
+              bDescDoclist, pPh->doclist.aAll, pPh->doclist.nAll,
+              &pIter, &iDocid, &dummy, &bEof
+              );
+        }
+      }
+      pPh->pOrPoslist = pIter;
+      pPh->iOrDocid = iDocid;
+      if( bEof || iDocid!=pCsr->iPrevId ) bMatch = 0;
+    }
+
+    if( bMatch ){
+      pIter = pPhrase->pOrPoslist;
+    }else{
+      pIter = 0;
+    }
+  }
+  if( pIter==0 ) return SQLITE_OK;
+
+  if( *pIter==0x01 ){
+    pIter++;
+    pIter += fts3GetVarint32(pIter, &iThis);
+  }else{
+    iThis = 0;
+  }
+  while( iThis<iCol ){
+    fts3ColumnlistCopy(0, &pIter);
+    if( *pIter==0x00 ) return SQLITE_OK;
+    pIter++;
+    pIter += fts3GetVarint32(pIter, &iThis);
+  }
+  if( *pIter==0x00 ){
+    pIter = 0;
+  }
+
+  *ppOut = ((iCol==iThis)?pIter:0);
+  return SQLITE_OK;
+}
+
+/*
+** Free all components of the Fts3Phrase structure that were allocated by
+** the eval module. Specifically, this means to free:
+**
+**   * the contents of pPhrase->doclist, and
+**   * any Fts3MultiSegReader objects held by phrase tokens.
+*/
+SQLITE_PRIVATE void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *pPhrase){
+  if( pPhrase ){
+    int i;
+    sqlite3_free(pPhrase->doclist.aAll);
+    fts3EvalInvalidatePoslist(pPhrase);
+    memset(&pPhrase->doclist, 0, sizeof(Fts3Doclist));
+    for(i=0; i<pPhrase->nToken; i++){
+      fts3SegReaderCursorFree(pPhrase->aToken[i].pSegcsr);
+      pPhrase->aToken[i].pSegcsr = 0;
+    }
+  }
+}
+
+
+/*
+** Return SQLITE_CORRUPT_VTAB.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3Fts3Corrupt(){
+  return SQLITE_CORRUPT_VTAB;
+}
+#endif
+
+#if !defined(SQLITE_CORE)
+/*
+** Initialize API pointer table, if required.
+*/
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_fts3_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi)
+  return sqlite3Fts3Init(db);
+}
+#endif
+
+#endif
+
+/************** End of fts3.c ************************************************/
+/************** Begin file fts3_aux.c ****************************************/
+/*
+** 2011 Jan 27
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+typedef struct Fts3auxTable Fts3auxTable;
+typedef struct Fts3auxCursor Fts3auxCursor;
+
+struct Fts3auxTable {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  Fts3Table *pFts3Tab;
+};
+
+struct Fts3auxCursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  Fts3MultiSegReader csr;        /* Must be right after "base" */
+  Fts3SegFilter filter;
+  char *zStop;
+  int nStop;                      /* Byte-length of string zStop */
+  int iLangid;                    /* Language id to query */
+  int isEof;                      /* True if cursor is at EOF */
+  sqlite3_int64 iRowid;           /* Current rowid */
+
+  int iCol;                       /* Current value of 'col' column */
+  int nStat;                      /* Size of aStat[] array */
+  struct Fts3auxColstats {
+    sqlite3_int64 nDoc;           /* 'documents' values for current csr row */
+    sqlite3_int64 nOcc;           /* 'occurrences' values for current csr row */
+  } *aStat;
+};
+
+/*
+** Schema of the terms table.
+*/
+#define FTS3_AUX_SCHEMA \
+  "CREATE TABLE x(term, col, documents, occurrences, languageid HIDDEN)"
+
+/*
+** This function does all the work for both the xConnect and xCreate methods.
+** These tables have no persistent representation of their own, so xConnect
+** and xCreate are identical operations.
+*/
+static int fts3auxConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pUnused,                  /* Unused */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  char const *zDb;                /* Name of database (e.g. "main") */
+  char const *zFts3;              /* Name of fts3 table */
+  int nDb;                        /* Result of strlen(zDb) */
+  int nFts3;                      /* Result of strlen(zFts3) */
+  sqlite3_int64 nByte;            /* Bytes of space to allocate here */
+  int rc;                         /* value returned by declare_vtab() */
+  Fts3auxTable *p;                /* Virtual table object to return */
+
+  UNUSED_PARAMETER(pUnused);
+
+  /* The user should invoke this in one of two forms:
+  **
+  **     CREATE VIRTUAL TABLE xxx USING fts4aux(fts4-table);
+  **     CREATE VIRTUAL TABLE xxx USING fts4aux(fts4-table-db, fts4-table);
+  */
+  if( argc!=4 && argc!=5 ) goto bad_args;
+
+  zDb = argv[1];
+  nDb = (int)strlen(zDb);
+  if( argc==5 ){
+    if( nDb==4 && 0==sqlite3_strnicmp("temp", zDb, 4) ){
+      zDb = argv[3];
+      nDb = (int)strlen(zDb);
+      zFts3 = argv[4];
+    }else{
+      goto bad_args;
+    }
+  }else{
+    zFts3 = argv[3];
+  }
+  nFts3 = (int)strlen(zFts3);
+
+  rc = sqlite3_declare_vtab(db, FTS3_AUX_SCHEMA);
+  if( rc!=SQLITE_OK ) return rc;
+
+  nByte = sizeof(Fts3auxTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
+  p = (Fts3auxTable *)sqlite3_malloc64(nByte);
+  if( !p ) return SQLITE_NOMEM;
+  memset(p, 0, nByte);
+
+  p->pFts3Tab = (Fts3Table *)&p[1];
+  p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
+  p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
+  p->pFts3Tab->db = db;
+  p->pFts3Tab->nIndex = 1;
+
+  memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
+  memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
+  sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);
+
+  *ppVtab = (sqlite3_vtab *)p;
+  return SQLITE_OK;
+
+ bad_args:
+  sqlite3Fts3ErrMsg(pzErr, "invalid arguments to fts4aux constructor");
+  return SQLITE_ERROR;
+}
+
+/*
+** This function does the work for both the xDisconnect and xDestroy methods.
+** These tables have no persistent representation of their own, so xDisconnect
+** and xDestroy are identical operations.
+*/
+static int fts3auxDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3auxTable *p = (Fts3auxTable *)pVtab;
+  Fts3Table *pFts3 = p->pFts3Tab;
+  int i;
+
+  /* Free any prepared statements held */
+  for(i=0; i<SizeofArray(pFts3->aStmt); i++){
+    sqlite3_finalize(pFts3->aStmt[i]);
+  }
+  sqlite3_free(pFts3->zSegmentsTbl);
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+#define FTS4AUX_EQ_CONSTRAINT 1
+#define FTS4AUX_GE_CONSTRAINT 2
+#define FTS4AUX_LE_CONSTRAINT 4
+
+/*
+** xBestIndex - Analyze a WHERE and ORDER BY clause.
+*/
+static int fts3auxBestIndexMethod(
+  sqlite3_vtab *pVTab,
+  sqlite3_index_info *pInfo
+){
+  int i;
+  int iEq = -1;
+  int iGe = -1;
+  int iLe = -1;
+  int iLangid = -1;
+  int iNext = 1;                  /* Next free argvIndex value */
+
+  UNUSED_PARAMETER(pVTab);
+
+  /* This vtab delivers always results in "ORDER BY term ASC" order. */
+  if( pInfo->nOrderBy==1
+   && pInfo->aOrderBy[0].iColumn==0
+   && pInfo->aOrderBy[0].desc==0
+  ){
+    pInfo->orderByConsumed = 1;
+  }
+
+  /* Search for equality and range constraints on the "term" column.
+  ** And equality constraints on the hidden "languageid" column. */
+  for(i=0; i<pInfo->nConstraint; i++){
+    if( pInfo->aConstraint[i].usable ){
+      int op = pInfo->aConstraint[i].op;
+      int iCol = pInfo->aConstraint[i].iColumn;
+
+      if( iCol==0 ){
+        if( op==SQLITE_INDEX_CONSTRAINT_EQ ) iEq = i;
+        if( op==SQLITE_INDEX_CONSTRAINT_LT ) iLe = i;
+        if( op==SQLITE_INDEX_CONSTRAINT_LE ) iLe = i;
+        if( op==SQLITE_INDEX_CONSTRAINT_GT ) iGe = i;
+        if( op==SQLITE_INDEX_CONSTRAINT_GE ) iGe = i;
+      }
+      if( iCol==4 ){
+        if( op==SQLITE_INDEX_CONSTRAINT_EQ ) iLangid = i;
+      }
+    }
+  }
+
+  if( iEq>=0 ){
+    pInfo->idxNum = FTS4AUX_EQ_CONSTRAINT;
+    pInfo->aConstraintUsage[iEq].argvIndex = iNext++;
+    pInfo->estimatedCost = 5;
+  }else{
+    pInfo->idxNum = 0;
+    pInfo->estimatedCost = 20000;
+    if( iGe>=0 ){
+      pInfo->idxNum += FTS4AUX_GE_CONSTRAINT;
+      pInfo->aConstraintUsage[iGe].argvIndex = iNext++;
+      pInfo->estimatedCost /= 2;
+    }
+    if( iLe>=0 ){
+      pInfo->idxNum += FTS4AUX_LE_CONSTRAINT;
+      pInfo->aConstraintUsage[iLe].argvIndex = iNext++;
+      pInfo->estimatedCost /= 2;
+    }
+  }
+  if( iLangid>=0 ){
+    pInfo->aConstraintUsage[iLangid].argvIndex = iNext++;
+    pInfo->estimatedCost--;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** xOpen - Open a cursor.
+*/
+static int fts3auxOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  Fts3auxCursor *pCsr;            /* Pointer to cursor object to return */
+
+  UNUSED_PARAMETER(pVTab);
+
+  pCsr = (Fts3auxCursor *)sqlite3_malloc(sizeof(Fts3auxCursor));
+  if( !pCsr ) return SQLITE_NOMEM;
+  memset(pCsr, 0, sizeof(Fts3auxCursor));
+
+  *ppCsr = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** xClose - Close a cursor.
+*/
+static int fts3auxCloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+
+  sqlite3Fts3SegmentsClose(pFts3);
+  sqlite3Fts3SegReaderFinish(&pCsr->csr);
+  sqlite3_free((void *)pCsr->filter.zTerm);
+  sqlite3_free(pCsr->zStop);
+  sqlite3_free(pCsr->aStat);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+static int fts3auxGrowStatArray(Fts3auxCursor *pCsr, int nSize){
+  if( nSize>pCsr->nStat ){
+    struct Fts3auxColstats *aNew;
+    aNew = (struct Fts3auxColstats *)sqlite3_realloc64(pCsr->aStat,
+        sizeof(struct Fts3auxColstats) * nSize
+    );
+    if( aNew==0 ) return SQLITE_NOMEM;
+    memset(&aNew[pCsr->nStat], 0,
+        sizeof(struct Fts3auxColstats) * (nSize - pCsr->nStat)
+    );
+    pCsr->aStat = aNew;
+    pCsr->nStat = nSize;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** xNext - Advance the cursor to the next row, if any.
+*/
+static int fts3auxNextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+  int rc;
+
+  /* Increment our pretend rowid value. */
+  pCsr->iRowid++;
+
+  for(pCsr->iCol++; pCsr->iCol<pCsr->nStat; pCsr->iCol++){
+    if( pCsr->aStat[pCsr->iCol].nDoc>0 ) return SQLITE_OK;
+  }
+
+  rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
+  if( rc==SQLITE_ROW ){
+    int i = 0;
+    int nDoclist = pCsr->csr.nDoclist;
+    char *aDoclist = pCsr->csr.aDoclist;
+    int iCol;
+
+    int eState = 0;
+
+    if( pCsr->zStop ){
+      int n = (pCsr->nStop<pCsr->csr.nTerm) ? pCsr->nStop : pCsr->csr.nTerm;
+      int mc = memcmp(pCsr->zStop, pCsr->csr.zTerm, n);
+      if( mc<0 || (mc==0 && pCsr->csr.nTerm>pCsr->nStop) ){
+        pCsr->isEof = 1;
+        return SQLITE_OK;
+      }
+    }
+
+    if( fts3auxGrowStatArray(pCsr, 2) ) return SQLITE_NOMEM;
+    memset(pCsr->aStat, 0, sizeof(struct Fts3auxColstats) * pCsr->nStat);
+    iCol = 0;
+    rc = SQLITE_OK;
+
+    while( i<nDoclist ){
+      sqlite3_int64 v = 0;
+
+      i += sqlite3Fts3GetVarint(&aDoclist[i], &v);
+      switch( eState ){
+        /* State 0. In this state the integer just read was a docid. */
+        case 0:
+          pCsr->aStat[0].nDoc++;
+          eState = 1;
+          iCol = 0;
+          break;
+
+        /* State 1. In this state we are expecting either a 1, indicating
+        ** that the following integer will be a column number, or the
+        ** start of a position list for column 0.
+        **
+        ** The only difference between state 1 and state 2 is that if the
+        ** integer encountered in state 1 is not 0 or 1, then we need to
+        ** increment the column 0 "nDoc" count for this term.
+        */
+        case 1:
+          assert( iCol==0 );
+          if( v>1 ){
+            pCsr->aStat[1].nDoc++;
+          }
+          eState = 2;
+          /* fall through */
+
+        case 2:
+          if( v==0 ){       /* 0x00. Next integer will be a docid. */
+            eState = 0;
+          }else if( v==1 ){ /* 0x01. Next integer will be a column number. */
+            eState = 3;
+          }else{            /* 2 or greater. A position. */
+            pCsr->aStat[iCol+1].nOcc++;
+            pCsr->aStat[0].nOcc++;
+          }
+          break;
+
+        /* State 3. The integer just read is a column number. */
+        default: assert( eState==3 );
+          iCol = (int)v;
+          if( iCol<1 ){
+            rc = SQLITE_CORRUPT_VTAB;
+            break;
+          }
+          if( fts3auxGrowStatArray(pCsr, iCol+2) ) return SQLITE_NOMEM;
+          pCsr->aStat[iCol+1].nDoc++;
+          eState = 2;
+          break;
+      }
+    }
+
+    pCsr->iCol = 0;
+  }else{
+    pCsr->isEof = 1;
+  }
+  return rc;
+}
+
+/*
+** xFilter - Initialize a cursor to point at the start of its data.
+*/
+static int fts3auxFilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+  int rc;
+  int isScan = 0;
+  int iLangVal = 0;               /* Language id to query */
+
+  int iEq = -1;                   /* Index of term=? value in apVal */
+  int iGe = -1;                   /* Index of term>=? value in apVal */
+  int iLe = -1;                   /* Index of term<=? value in apVal */
+  int iLangid = -1;               /* Index of languageid=? value in apVal */
+  int iNext = 0;
+
+  UNUSED_PARAMETER(nVal);
+  UNUSED_PARAMETER(idxStr);
+
+  assert( idxStr==0 );
+  assert( idxNum==FTS4AUX_EQ_CONSTRAINT || idxNum==0
+       || idxNum==FTS4AUX_LE_CONSTRAINT || idxNum==FTS4AUX_GE_CONSTRAINT
+       || idxNum==(FTS4AUX_LE_CONSTRAINT|FTS4AUX_GE_CONSTRAINT)
+  );
+
+  if( idxNum==FTS4AUX_EQ_CONSTRAINT ){
+    iEq = iNext++;
+  }else{
+    isScan = 1;
+    if( idxNum & FTS4AUX_GE_CONSTRAINT ){
+      iGe = iNext++;
+    }
+    if( idxNum & FTS4AUX_LE_CONSTRAINT ){
+      iLe = iNext++;
+    }
+  }
+  if( iNext<nVal ){
+    iLangid = iNext++;
+  }
+
+  /* In case this cursor is being reused, close and zero it. */
+  testcase(pCsr->filter.zTerm);
+  sqlite3Fts3SegReaderFinish(&pCsr->csr);
+  sqlite3_free((void *)pCsr->filter.zTerm);
+  sqlite3_free(pCsr->aStat);
+  sqlite3_free(pCsr->zStop);
+  memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);
+
+  pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
+  if( isScan ) pCsr->filter.flags |= FTS3_SEGMENT_SCAN;
+
+  if( iEq>=0 || iGe>=0 ){
+    const unsigned char *zStr = sqlite3_value_text(apVal[0]);
+    assert( (iEq==0 && iGe==-1) || (iEq==-1 && iGe==0) );
+    if( zStr ){
+      pCsr->filter.zTerm = sqlite3_mprintf("%s", zStr);
+      if( pCsr->filter.zTerm==0 ) return SQLITE_NOMEM;
+      pCsr->filter.nTerm = (int)strlen(pCsr->filter.zTerm);
+    }
+  }
+
+  if( iLe>=0 ){
+    pCsr->zStop = sqlite3_mprintf("%s", sqlite3_value_text(apVal[iLe]));
+    if( pCsr->zStop==0 ) return SQLITE_NOMEM;
+    pCsr->nStop = (int)strlen(pCsr->zStop);
+  }
+
+  if( iLangid>=0 ){
+    iLangVal = sqlite3_value_int(apVal[iLangid]);
+
+    /* If the user specified a negative value for the languageid, use zero
+    ** instead. This works, as the "languageid=?" constraint will also
+    ** be tested by the VDBE layer. The test will always be false (since
+    ** this module will not return a row with a negative languageid), and
+    ** so the overall query will return zero rows.  */
+    if( iLangVal<0 ) iLangVal = 0;
+  }
+  pCsr->iLangid = iLangVal;
+
+  rc = sqlite3Fts3SegReaderCursor(pFts3, iLangVal, 0, FTS3_SEGCURSOR_ALL,
+      pCsr->filter.zTerm, pCsr->filter.nTerm, 0, isScan, &pCsr->csr
+  );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
+  }
+
+  if( rc==SQLITE_OK ) rc = fts3auxNextMethod(pCursor);
+  return rc;
+}
+
+/*
+** xEof - Return true if the cursor is at EOF, or false otherwise.
+*/
+static int fts3auxEofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  return pCsr->isEof;
+}
+
+/*
+** xColumn - Return a column value.
+*/
+static int fts3auxColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts3auxCursor *p = (Fts3auxCursor *)pCursor;
+
+  assert( p->isEof==0 );
+  switch( iCol ){
+    case 0: /* term */
+      sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
+      break;
+
+    case 1: /* col */
+      if( p->iCol ){
+        sqlite3_result_int(pCtx, p->iCol-1);
+      }else{
+        sqlite3_result_text(pCtx, "*", -1, SQLITE_STATIC);
+      }
+      break;
+
+    case 2: /* documents */
+      sqlite3_result_int64(pCtx, p->aStat[p->iCol].nDoc);
+      break;
+
+    case 3: /* occurrences */
+      sqlite3_result_int64(pCtx, p->aStat[p->iCol].nOcc);
+      break;
+
+    default: /* languageid */
+      assert( iCol==4 );
+      sqlite3_result_int(pCtx, p->iLangid);
+      break;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** xRowid - Return the current rowid for the cursor.
+*/
+static int fts3auxRowidMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite_int64 *pRowid            /* OUT: Rowid value */
+){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  *pRowid = pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Register the fts3aux module with database connection db. Return SQLITE_OK
+** if successful or an error code if sqlite3_create_module() fails.
+*/
+SQLITE_PRIVATE int sqlite3Fts3InitAux(sqlite3 *db){
+  static const sqlite3_module fts3aux_module = {
+     0,                           /* iVersion      */
+     fts3auxConnectMethod,        /* xCreate       */
+     fts3auxConnectMethod,        /* xConnect      */
+     fts3auxBestIndexMethod,      /* xBestIndex    */
+     fts3auxDisconnectMethod,     /* xDisconnect   */
+     fts3auxDisconnectMethod,     /* xDestroy      */
+     fts3auxOpenMethod,           /* xOpen         */
+     fts3auxCloseMethod,          /* xClose        */
+     fts3auxFilterMethod,         /* xFilter       */
+     fts3auxNextMethod,           /* xNext         */
+     fts3auxEofMethod,            /* xEof          */
+     fts3auxColumnMethod,         /* xColumn       */
+     fts3auxRowidMethod,          /* xRowid        */
+     0,                           /* xUpdate       */
+     0,                           /* xBegin        */
+     0,                           /* xSync         */
+     0,                           /* xCommit       */
+     0,                           /* xRollback     */
+     0,                           /* xFindFunction */
+     0,                           /* xRename       */
+     0,                           /* xSavepoint    */
+     0,                           /* xRelease      */
+     0,                           /* xRollbackTo   */
+     0,                           /* xShadowName   */
+     0                            /* xIntegrity    */
+  };
+  int rc;                         /* Return code */
+
+  rc = sqlite3_create_module(db, "fts4aux", &fts3aux_module, 0);
+  return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_aux.c ********************************************/
+/************** Begin file fts3_expr.c ***************************************/
+/*
+** 2008 Nov 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This module contains code that implements a parser for fts3 query strings
+** (the right-hand argument to the MATCH operator). Because the supported
+** syntax is relatively simple, the whole tokenizer/parser system is
+** hand-coded.
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/*
+** By default, this module parses the legacy syntax that has been
+** traditionally used by fts3. Or, if SQLITE_ENABLE_FTS3_PARENTHESIS
+** is defined, then it uses the new syntax. The differences between
+** the new and the old syntaxes are:
+**
+**  a) The new syntax supports parenthesis. The old does not.
+**
+**  b) The new syntax supports the AND and NOT operators. The old does not.
+**
+**  c) The old syntax supports the "-" token qualifier. This is not
+**     supported by the new syntax (it is replaced by the NOT operator).
+**
+**  d) When using the old syntax, the OR operator has a greater precedence
+**     than an implicit AND. When using the new, both implicity and explicit
+**     AND operators have a higher precedence than OR.
+**
+** If compiled with SQLITE_TEST defined, then this module exports the
+** symbol "int sqlite3_fts3_enable_parentheses". Setting this variable
+** to zero causes the module to use the old syntax. If it is set to
+** non-zero the new syntax is activated. This is so both syntaxes can
+** be tested using a single build of testfixture.
+**
+** The following describes the syntax supported by the fts3 MATCH
+** operator in a similar format to that used by the lemon parser
+** generator. This module does not use actually lemon, it uses a
+** custom parser.
+**
+**   query ::= andexpr (OR andexpr)*.
+**
+**   andexpr ::= notexpr (AND? notexpr)*.
+**
+**   notexpr ::= nearexpr (NOT nearexpr|-TOKEN)*.
+**   notexpr ::= LP query RP.
+**
+**   nearexpr ::= phrase (NEAR distance_opt nearexpr)*.
+**
+**   distance_opt ::= .
+**   distance_opt ::= / INTEGER.
+**
+**   phrase ::= TOKEN.
+**   phrase ::= COLUMN:TOKEN.
+**   phrase ::= "TOKEN TOKEN TOKEN...".
+*/
+
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_fts3_enable_parentheses = 0;
+#else
+# ifdef SQLITE_ENABLE_FTS3_PARENTHESIS
+#  define sqlite3_fts3_enable_parentheses 1
+# else
+#  define sqlite3_fts3_enable_parentheses 0
+# endif
+#endif
+
+/*
+** Default span for NEAR operators.
+*/
+#define SQLITE_FTS3_DEFAULT_NEAR_PARAM 10
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+/*
+** isNot:
+**   This variable is used by function getNextNode(). When getNextNode() is
+**   called, it sets ParseContext.isNot to true if the 'next node' is a
+**   FTSQUERY_PHRASE with a unary "-" attached to it. i.e. "mysql" in the
+**   FTS3 query "sqlite -mysql". Otherwise, ParseContext.isNot is set to
+**   zero.
+*/
+typedef struct ParseContext ParseContext;
+struct ParseContext {
+  sqlite3_tokenizer *pTokenizer;      /* Tokenizer module */
+  int iLangid;                        /* Language id used with tokenizer */
+  const char **azCol;                 /* Array of column names for fts3 table */
+  int bFts4;                          /* True to allow FTS4-only syntax */
+  int nCol;                           /* Number of entries in azCol[] */
+  int iDefaultCol;                    /* Default column to query */
+  int isNot;                          /* True if getNextNode() sees a unary - */
+  sqlite3_context *pCtx;              /* Write error message here */
+  int nNest;                          /* Number of nested brackets */
+};
+
+/*
+** This function is equivalent to the standard isspace() function.
+**
+** The standard isspace() can be awkward to use safely, because although it
+** is defined to accept an argument of type int, its behavior when passed
+** an integer that falls outside of the range of the unsigned char type
+** is undefined (and sometimes, "undefined" means segfault). This wrapper
+** is defined to accept an argument of type char, and always returns 0 for
+** any values that fall outside of the range of the unsigned char type (i.e.
+** negative values).
+*/
+static int fts3isspace(char c){
+  return c==' ' || c=='\t' || c=='\n' || c=='\r' || c=='\v' || c=='\f';
+}
+
+/*
+** Allocate nByte bytes of memory using sqlite3_malloc(). If successful,
+** zero the memory before returning a pointer to it. If unsuccessful,
+** return NULL.
+*/
+SQLITE_PRIVATE void *sqlite3Fts3MallocZero(sqlite3_int64 nByte){
+  void *pRet = sqlite3_malloc64(nByte);
+  if( pRet ) memset(pRet, 0, nByte);
+  return pRet;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3OpenTokenizer(
+  sqlite3_tokenizer *pTokenizer,
+  int iLangid,
+  const char *z,
+  int n,
+  sqlite3_tokenizer_cursor **ppCsr
+){
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  sqlite3_tokenizer_cursor *pCsr = 0;
+  int rc;
+
+  rc = pModule->xOpen(pTokenizer, z, n, &pCsr);
+  assert( rc==SQLITE_OK || pCsr==0 );
+  if( rc==SQLITE_OK ){
+    pCsr->pTokenizer = pTokenizer;
+    if( pModule->iVersion>=1 ){
+      rc = pModule->xLanguageid(pCsr, iLangid);
+      if( rc!=SQLITE_OK ){
+        pModule->xClose(pCsr);
+        pCsr = 0;
+      }
+    }
+  }
+  *ppCsr = pCsr;
+  return rc;
+}
+
+/*
+** Function getNextNode(), which is called by fts3ExprParse(), may itself
+** call fts3ExprParse(). So this forward declaration is required.
+*/
+static int fts3ExprParse(ParseContext *, const char *, int, Fts3Expr **, int *);
+
+/*
+** Extract the next token from buffer z (length n) using the tokenizer
+** and other information (column names etc.) in pParse. Create an Fts3Expr
+** structure of type FTSQUERY_PHRASE containing a phrase consisting of this
+** single token and set *ppExpr to point to it. If the end of the buffer is
+** reached before a token is found, set *ppExpr to zero. It is the
+** responsibility of the caller to eventually deallocate the allocated
+** Fts3Expr structure (if any) by passing it to sqlite3_free().
+**
+** Return SQLITE_OK if successful, or SQLITE_NOMEM if a memory allocation
+** fails.
+*/
+static int getNextToken(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  int iCol,                               /* Value for Fts3Phrase.iColumn */
+  const char *z, int n,                   /* Input string */
+  Fts3Expr **ppExpr,                      /* OUT: expression */
+  int *pnConsumed                         /* OUT: Number of bytes consumed */
+){
+  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  int rc;
+  sqlite3_tokenizer_cursor *pCursor;
+  Fts3Expr *pRet = 0;
+  int i = 0;
+
+  /* Set variable i to the maximum number of bytes of input to tokenize. */
+  for(i=0; i<n; i++){
+    if( sqlite3_fts3_enable_parentheses && (z[i]=='(' || z[i]==')') ) break;
+    if( z[i]=='"' ) break;
+  }
+
+  *pnConsumed = i;
+  rc = sqlite3Fts3OpenTokenizer(pTokenizer, pParse->iLangid, z, i, &pCursor);
+  if( rc==SQLITE_OK ){
+    const char *zToken;
+    int nToken = 0, iStart = 0, iEnd = 0, iPosition = 0;
+    sqlite3_int64 nByte;                    /* total space to allocate */
+
+    rc = pModule->xNext(pCursor, &zToken, &nToken, &iStart, &iEnd, &iPosition);
+    if( rc==SQLITE_OK ){
+      nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase) + nToken;
+      pRet = (Fts3Expr *)sqlite3Fts3MallocZero(nByte);
+      if( !pRet ){
+        rc = SQLITE_NOMEM;
+      }else{
+        pRet->eType = FTSQUERY_PHRASE;
+        pRet->pPhrase = (Fts3Phrase *)&pRet[1];
+        pRet->pPhrase->nToken = 1;
+        pRet->pPhrase->iColumn = iCol;
+        pRet->pPhrase->aToken[0].n = nToken;
+        pRet->pPhrase->aToken[0].z = (char *)&pRet->pPhrase[1];
+        memcpy(pRet->pPhrase->aToken[0].z, zToken, nToken);
+
+        if( iEnd<n && z[iEnd]=='*' ){
+          pRet->pPhrase->aToken[0].isPrefix = 1;
+          iEnd++;
+        }
+
+        while( 1 ){
+          if( !sqlite3_fts3_enable_parentheses
+           && iStart>0 && z[iStart-1]=='-'
+          ){
+            pParse->isNot = 1;
+            iStart--;
+          }else if( pParse->bFts4 && iStart>0 && z[iStart-1]=='^' ){
+            pRet->pPhrase->aToken[0].bFirst = 1;
+            iStart--;
+          }else{
+            break;
+          }
+        }
+
+      }
+      *pnConsumed = iEnd;
+    }else if( i && rc==SQLITE_DONE ){
+      rc = SQLITE_OK;
+    }
+
+    pModule->xClose(pCursor);
+  }
+
+  *ppExpr = pRet;
+  return rc;
+}
+
+
+/*
+** Enlarge a memory allocation.  If an out-of-memory allocation occurs,
+** then free the old allocation.
+*/
+static void *fts3ReallocOrFree(void *pOrig, sqlite3_int64 nNew){
+  void *pRet = sqlite3_realloc64(pOrig, nNew);
+  if( !pRet ){
+    sqlite3_free(pOrig);
+  }
+  return pRet;
+}
+
+/*
+** Buffer zInput, length nInput, contains the contents of a quoted string
+** that appeared as part of an fts3 query expression. Neither quote character
+** is included in the buffer. This function attempts to tokenize the entire
+** input buffer and create an Fts3Expr structure of type FTSQUERY_PHRASE
+** containing the results.
+**
+** If successful, SQLITE_OK is returned and *ppExpr set to point at the
+** allocated Fts3Expr structure. Otherwise, either SQLITE_NOMEM (out of memory
+** error) or SQLITE_ERROR (tokenization error) is returned and *ppExpr set
+** to 0.
+*/
+static int getNextString(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  const char *zInput, int nInput,         /* Input string */
+  Fts3Expr **ppExpr                       /* OUT: expression */
+){
+  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  int rc;
+  Fts3Expr *p = 0;
+  sqlite3_tokenizer_cursor *pCursor = 0;
+  char *zTemp = 0;
+  int nTemp = 0;
+
+  const int nSpace = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
+  int nToken = 0;
+
+  /* The final Fts3Expr data structure, including the Fts3Phrase,
+  ** Fts3PhraseToken structures token buffers are all stored as a single
+  ** allocation so that the expression can be freed with a single call to
+  ** sqlite3_free(). Setting this up requires a two pass approach.
+  **
+  ** The first pass, in the block below, uses a tokenizer cursor to iterate
+  ** through the tokens in the expression. This pass uses fts3ReallocOrFree()
+  ** to assemble data in two dynamic buffers:
+  **
+  **   Buffer p: Points to the Fts3Expr structure, followed by the Fts3Phrase
+  **             structure, followed by the array of Fts3PhraseToken
+  **             structures. This pass only populates the Fts3PhraseToken array.
+  **
+  **   Buffer zTemp: Contains copies of all tokens.
+  **
+  ** The second pass, in the block that begins "if( rc==SQLITE_DONE )" below,
+  ** appends buffer zTemp to buffer p, and fills in the Fts3Expr and Fts3Phrase
+  ** structures.
+  */
+  rc = sqlite3Fts3OpenTokenizer(
+      pTokenizer, pParse->iLangid, zInput, nInput, &pCursor);
+  if( rc==SQLITE_OK ){
+    int ii;
+    for(ii=0; rc==SQLITE_OK; ii++){
+      const char *zByte;
+      int nByte = 0, iBegin = 0, iEnd = 0, iPos = 0;
+      rc = pModule->xNext(pCursor, &zByte, &nByte, &iBegin, &iEnd, &iPos);
+      if( rc==SQLITE_OK ){
+        Fts3PhraseToken *pToken;
+
+        p = fts3ReallocOrFree(p, nSpace + ii*sizeof(Fts3PhraseToken));
+        zTemp = fts3ReallocOrFree(zTemp, nTemp + nByte);
+        if( !zTemp || !p ){
+          rc = SQLITE_NOMEM;
+          goto getnextstring_out;
+        }
+
+        assert( nToken==ii );
+        pToken = &((Fts3Phrase *)(&p[1]))->aToken[ii];
+        memset(pToken, 0, sizeof(Fts3PhraseToken));
+
+        memcpy(&zTemp[nTemp], zByte, nByte);
+        nTemp += nByte;
+
+        pToken->n = nByte;
+        pToken->isPrefix = (iEnd<nInput && zInput[iEnd]=='*');
+        pToken->bFirst = (iBegin>0 && zInput[iBegin-1]=='^');
+        nToken = ii+1;
+      }
+    }
+  }
+
+  if( rc==SQLITE_DONE ){
+    int jj;
+    char *zBuf = 0;
+
+    p = fts3ReallocOrFree(p, nSpace + nToken*sizeof(Fts3PhraseToken) + nTemp);
+    if( !p ){
+      rc = SQLITE_NOMEM;
+      goto getnextstring_out;
+    }
+    memset(p, 0, (char *)&(((Fts3Phrase *)&p[1])->aToken[0])-(char *)p);
+    p->eType = FTSQUERY_PHRASE;
+    p->pPhrase = (Fts3Phrase *)&p[1];
+    p->pPhrase->iColumn = pParse->iDefaultCol;
+    p->pPhrase->nToken = nToken;
+
+    zBuf = (char *)&p->pPhrase->aToken[nToken];
+    assert( nTemp==0 || zTemp );
+    if( zTemp ){
+      memcpy(zBuf, zTemp, nTemp);
+    }
+
+    for(jj=0; jj<p->pPhrase->nToken; jj++){
+      p->pPhrase->aToken[jj].z = zBuf;
+      zBuf += p->pPhrase->aToken[jj].n;
+    }
+    rc = SQLITE_OK;
+  }
+
+ getnextstring_out:
+  if( pCursor ){
+    pModule->xClose(pCursor);
+  }
+  sqlite3_free(zTemp);
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(p);
+    p = 0;
+  }
+  *ppExpr = p;
+  return rc;
+}
+
+/*
+** The output variable *ppExpr is populated with an allocated Fts3Expr
+** structure, or set to 0 if the end of the input buffer is reached.
+**
+** Returns an SQLite error code. SQLITE_OK if everything works, SQLITE_NOMEM
+** if a malloc failure occurs, or SQLITE_ERROR if a parse error is encountered.
+** If SQLITE_ERROR is returned, pContext is populated with an error message.
+*/
+static int getNextNode(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  const char *z, int n,                   /* Input string */
+  Fts3Expr **ppExpr,                      /* OUT: expression */
+  int *pnConsumed                         /* OUT: Number of bytes consumed */
+){
+  static const struct Fts3Keyword {
+    char *z;                              /* Keyword text */
+    unsigned char n;                      /* Length of the keyword */
+    unsigned char parenOnly;              /* Only valid in paren mode */
+    unsigned char eType;                  /* Keyword code */
+  } aKeyword[] = {
+    { "OR" ,  2, 0, FTSQUERY_OR   },
+    { "AND",  3, 1, FTSQUERY_AND  },
+    { "NOT",  3, 1, FTSQUERY_NOT  },
+    { "NEAR", 4, 0, FTSQUERY_NEAR }
+  };
+  int ii;
+  int iCol;
+  int iColLen;
+  int rc;
+  Fts3Expr *pRet = 0;
+
+  const char *zInput = z;
+  int nInput = n;
+
+  pParse->isNot = 0;
+
+  /* Skip over any whitespace before checking for a keyword, an open or
+  ** close bracket, or a quoted string.
+  */
+  while( nInput>0 && fts3isspace(*zInput) ){
+    nInput--;
+    zInput++;
+  }
+  if( nInput==0 ){
+    return SQLITE_DONE;
+  }
+
+  /* See if we are dealing with a keyword. */
+  for(ii=0; ii<(int)(sizeof(aKeyword)/sizeof(struct Fts3Keyword)); ii++){
+    const struct Fts3Keyword *pKey = &aKeyword[ii];
+
+    if( (pKey->parenOnly & ~sqlite3_fts3_enable_parentheses)!=0 ){
+      continue;
+    }
+
+    if( nInput>=pKey->n && 0==memcmp(zInput, pKey->z, pKey->n) ){
+      int nNear = SQLITE_FTS3_DEFAULT_NEAR_PARAM;
+      int nKey = pKey->n;
+      char cNext;
+
+      /* If this is a "NEAR" keyword, check for an explicit nearness. */
+      if( pKey->eType==FTSQUERY_NEAR ){
+        assert( nKey==4 );
+        if( zInput[4]=='/' && zInput[5]>='0' && zInput[5]<='9' ){
+          nKey += 1+sqlite3Fts3ReadInt(&zInput[nKey+1], &nNear);
+        }
+      }
+
+      /* At this point this is probably a keyword. But for that to be true,
+      ** the next byte must contain either whitespace, an open or close
+      ** parenthesis, a quote character, or EOF.
+      */
+      cNext = zInput[nKey];
+      if( fts3isspace(cNext)
+       || cNext=='"' || cNext=='(' || cNext==')' || cNext==0
+      ){
+        pRet = (Fts3Expr *)sqlite3Fts3MallocZero(sizeof(Fts3Expr));
+        if( !pRet ){
+          return SQLITE_NOMEM;
+        }
+        pRet->eType = pKey->eType;
+        pRet->nNear = nNear;
+        *ppExpr = pRet;
+        *pnConsumed = (int)((zInput - z) + nKey);
+        return SQLITE_OK;
+      }
+
+      /* Turns out that wasn't a keyword after all. This happens if the
+      ** user has supplied a token such as "ORacle". Continue.
+      */
+    }
+  }
+
+  /* See if we are dealing with a quoted phrase. If this is the case, then
+  ** search for the closing quote and pass the whole string to getNextString()
+  ** for processing. This is easy to do, as fts3 has no syntax for escaping
+  ** a quote character embedded in a string.
+  */
+  if( *zInput=='"' ){
+    for(ii=1; ii<nInput && zInput[ii]!='"'; ii++);
+    *pnConsumed = (int)((zInput - z) + ii + 1);
+    if( ii==nInput ){
+      return SQLITE_ERROR;
+    }
+    return getNextString(pParse, &zInput[1], ii-1, ppExpr);
+  }
+
+  if( sqlite3_fts3_enable_parentheses ){
+    if( *zInput=='(' ){
+      int nConsumed = 0;
+      pParse->nNest++;
+#if !defined(SQLITE_MAX_EXPR_DEPTH)
+      if( pParse->nNest>1000 ) return SQLITE_ERROR;
+#elif SQLITE_MAX_EXPR_DEPTH>0
+      if( pParse->nNest>SQLITE_MAX_EXPR_DEPTH ) return SQLITE_ERROR;
+#endif
+      rc = fts3ExprParse(pParse, zInput+1, nInput-1, ppExpr, &nConsumed);
+      *pnConsumed = (int)(zInput - z) + 1 + nConsumed;
+      return rc;
+    }else if( *zInput==')' ){
+      pParse->nNest--;
+      *pnConsumed = (int)((zInput - z) + 1);
+      *ppExpr = 0;
+      return SQLITE_DONE;
+    }
+  }
+
+  /* If control flows to this point, this must be a regular token, or
+  ** the end of the input. Read a regular token using the sqlite3_tokenizer
+  ** interface. Before doing so, figure out if there is an explicit
+  ** column specifier for the token.
+  **
+  ** TODO: Strangely, it is not possible to associate a column specifier
+  ** with a quoted phrase, only with a single token. Not sure if this was
+  ** an implementation artifact or an intentional decision when fts3 was
+  ** first implemented. Whichever it was, this module duplicates the
+  ** limitation.
+  */
+  iCol = pParse->iDefaultCol;
+  iColLen = 0;
+  for(ii=0; ii<pParse->nCol; ii++){
+    const char *zStr = pParse->azCol[ii];
+    int nStr = (int)strlen(zStr);
+    if( nInput>nStr && zInput[nStr]==':'
+     && sqlite3_strnicmp(zStr, zInput, nStr)==0
+    ){
+      iCol = ii;
+      iColLen = (int)((zInput - z) + nStr + 1);
+      break;
+    }
+  }
+  rc = getNextToken(pParse, iCol, &z[iColLen], n-iColLen, ppExpr, pnConsumed);
+  *pnConsumed += iColLen;
+  return rc;
+}
+
+/*
+** The argument is an Fts3Expr structure for a binary operator (any type
+** except an FTSQUERY_PHRASE). Return an integer value representing the
+** precedence of the operator. Lower values have a higher precedence (i.e.
+** group more tightly). For example, in the C language, the == operator
+** groups more tightly than ||, and would therefore have a higher precedence.
+**
+** When using the new fts3 query syntax (when SQLITE_ENABLE_FTS3_PARENTHESIS
+** is defined), the order of the operators in precedence from highest to
+** lowest is:
+**
+**   NEAR
+**   NOT
+**   AND (including implicit ANDs)
+**   OR
+**
+** Note that when using the old query syntax, the OR operator has a higher
+** precedence than the AND operator.
+*/
+static int opPrecedence(Fts3Expr *p){
+  assert( p->eType!=FTSQUERY_PHRASE );
+  if( sqlite3_fts3_enable_parentheses ){
+    return p->eType;
+  }else if( p->eType==FTSQUERY_NEAR ){
+    return 1;
+  }else if( p->eType==FTSQUERY_OR ){
+    return 2;
+  }
+  assert( p->eType==FTSQUERY_AND );
+  return 3;
+}
+
+/*
+** Argument ppHead contains a pointer to the current head of a query
+** expression tree being parsed. pPrev is the expression node most recently
+** inserted into the tree. This function adds pNew, which is always a binary
+** operator node, into the expression tree based on the relative precedence
+** of pNew and the existing nodes of the tree. This may result in the head
+** of the tree changing, in which case *ppHead is set to the new root node.
+*/
+static void insertBinaryOperator(
+  Fts3Expr **ppHead,       /* Pointer to the root node of a tree */
+  Fts3Expr *pPrev,         /* Node most recently inserted into the tree */
+  Fts3Expr *pNew           /* New binary node to insert into expression tree */
+){
+  Fts3Expr *pSplit = pPrev;
+  while( pSplit->pParent && opPrecedence(pSplit->pParent)<=opPrecedence(pNew) ){
+    pSplit = pSplit->pParent;
+  }
+
+  if( pSplit->pParent ){
+    assert( pSplit->pParent->pRight==pSplit );
+    pSplit->pParent->pRight = pNew;
+    pNew->pParent = pSplit->pParent;
+  }else{
+    *ppHead = pNew;
+  }
+  pNew->pLeft = pSplit;
+  pSplit->pParent = pNew;
+}
+
+/*
+** Parse the fts3 query expression found in buffer z, length n. This function
+** returns either when the end of the buffer is reached or an unmatched
+** closing bracket - ')' - is encountered.
+**
+** If successful, SQLITE_OK is returned, *ppExpr is set to point to the
+** parsed form of the expression and *pnConsumed is set to the number of
+** bytes read from buffer z. Otherwise, *ppExpr is set to 0 and SQLITE_NOMEM
+** (out of memory error) or SQLITE_ERROR (parse error) is returned.
+*/
+static int fts3ExprParse(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  const char *z, int n,                   /* Text of MATCH query */
+  Fts3Expr **ppExpr,                      /* OUT: Parsed query structure */
+  int *pnConsumed                         /* OUT: Number of bytes consumed */
+){
+  Fts3Expr *pRet = 0;
+  Fts3Expr *pPrev = 0;
+  Fts3Expr *pNotBranch = 0;               /* Only used in legacy parse mode */
+  int nIn = n;
+  const char *zIn = z;
+  int rc = SQLITE_OK;
+  int isRequirePhrase = 1;
+
+  while( rc==SQLITE_OK ){
+    Fts3Expr *p = 0;
+    int nByte = 0;
+
+    rc = getNextNode(pParse, zIn, nIn, &p, &nByte);
+    assert( nByte>0 || (rc!=SQLITE_OK && p==0) );
+    if( rc==SQLITE_OK ){
+      if( p ){
+        int isPhrase;
+
+        if( !sqlite3_fts3_enable_parentheses
+            && p->eType==FTSQUERY_PHRASE && pParse->isNot
+        ){
+          /* Create an implicit NOT operator. */
+          Fts3Expr *pNot = sqlite3Fts3MallocZero(sizeof(Fts3Expr));
+          if( !pNot ){
+            sqlite3Fts3ExprFree(p);
+            rc = SQLITE_NOMEM;
+            goto exprparse_out;
+          }
+          pNot->eType = FTSQUERY_NOT;
+          pNot->pRight = p;
+          p->pParent = pNot;
+          if( pNotBranch ){
+            pNot->pLeft = pNotBranch;
+            pNotBranch->pParent = pNot;
+          }
+          pNotBranch = pNot;
+          p = pPrev;
+        }else{
+          int eType = p->eType;
+          isPhrase = (eType==FTSQUERY_PHRASE || p->pLeft);
+
+          /* The isRequirePhrase variable is set to true if a phrase or
+          ** an expression contained in parenthesis is required. If a
+          ** binary operator (AND, OR, NOT or NEAR) is encounted when
+          ** isRequirePhrase is set, this is a syntax error.
+          */
+          if( !isPhrase && isRequirePhrase ){
+            sqlite3Fts3ExprFree(p);
+            rc = SQLITE_ERROR;
+            goto exprparse_out;
+          }
+
+          if( isPhrase && !isRequirePhrase ){
+            /* Insert an implicit AND operator. */
+            Fts3Expr *pAnd;
+            assert( pRet && pPrev );
+            pAnd = sqlite3Fts3MallocZero(sizeof(Fts3Expr));
+            if( !pAnd ){
+              sqlite3Fts3ExprFree(p);
+              rc = SQLITE_NOMEM;
+              goto exprparse_out;
+            }
+            pAnd->eType = FTSQUERY_AND;
+            insertBinaryOperator(&pRet, pPrev, pAnd);
+            pPrev = pAnd;
+          }
+
+          /* This test catches attempts to make either operand of a NEAR
+           ** operator something other than a phrase. For example, either of
+           ** the following:
+           **
+           **    (bracketed expression) NEAR phrase
+           **    phrase NEAR (bracketed expression)
+           **
+           ** Return an error in either case.
+           */
+          if( pPrev && (
+            (eType==FTSQUERY_NEAR && !isPhrase && pPrev->eType!=FTSQUERY_PHRASE)
+         || (eType!=FTSQUERY_PHRASE && isPhrase && pPrev->eType==FTSQUERY_NEAR)
+          )){
+            sqlite3Fts3ExprFree(p);
+            rc = SQLITE_ERROR;
+            goto exprparse_out;
+          }
+
+          if( isPhrase ){
+            if( pRet ){
+              assert( pPrev && pPrev->pLeft && pPrev->pRight==0 );
+              pPrev->pRight = p;
+              p->pParent = pPrev;
+            }else{
+              pRet = p;
+            }
+          }else{
+            insertBinaryOperator(&pRet, pPrev, p);
+          }
+          isRequirePhrase = !isPhrase;
+        }
+        pPrev = p;
+      }
+      assert( nByte>0 );
+    }
+    assert( rc!=SQLITE_OK || (nByte>0 && nByte<=nIn) );
+    nIn -= nByte;
+    zIn += nByte;
+  }
+
+  if( rc==SQLITE_DONE && pRet && isRequirePhrase ){
+    rc = SQLITE_ERROR;
+  }
+
+  if( rc==SQLITE_DONE ){
+    rc = SQLITE_OK;
+    if( !sqlite3_fts3_enable_parentheses && pNotBranch ){
+      if( !pRet ){
+        rc = SQLITE_ERROR;
+      }else{
+        Fts3Expr *pIter = pNotBranch;
+        while( pIter->pLeft ){
+          pIter = pIter->pLeft;
+        }
+        pIter->pLeft = pRet;
+        pRet->pParent = pIter;
+        pRet = pNotBranch;
+      }
+    }
+  }
+  *pnConsumed = n - nIn;
+
+exprparse_out:
+  if( rc!=SQLITE_OK ){
+    sqlite3Fts3ExprFree(pRet);
+    sqlite3Fts3ExprFree(pNotBranch);
+    pRet = 0;
+  }
+  *ppExpr = pRet;
+  return rc;
+}
+
+/*
+** Return SQLITE_ERROR if the maximum depth of the expression tree passed
+** as the only argument is more than nMaxDepth.
+*/
+static int fts3ExprCheckDepth(Fts3Expr *p, int nMaxDepth){
+  int rc = SQLITE_OK;
+  if( p ){
+    if( nMaxDepth<0 ){
+      rc = SQLITE_TOOBIG;
+    }else{
+      rc = fts3ExprCheckDepth(p->pLeft, nMaxDepth-1);
+      if( rc==SQLITE_OK ){
+        rc = fts3ExprCheckDepth(p->pRight, nMaxDepth-1);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** This function attempts to transform the expression tree at (*pp) to
+** an equivalent but more balanced form. The tree is modified in place.
+** If successful, SQLITE_OK is returned and (*pp) set to point to the
+** new root expression node.
+**
+** nMaxDepth is the maximum allowable depth of the balanced sub-tree.
+**
+** Otherwise, if an error occurs, an SQLite error code is returned and
+** expression (*pp) freed.
+*/
+static int fts3ExprBalance(Fts3Expr **pp, int nMaxDepth){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts3Expr *pRoot = *pp;          /* Initial root node */
+  Fts3Expr *pFree = 0;            /* List of free nodes. Linked by pParent. */
+  int eType = pRoot->eType;       /* Type of node in this tree */
+
+  if( nMaxDepth==0 ){
+    rc = SQLITE_ERROR;
+  }
+
+  if( rc==SQLITE_OK ){
+    if( (eType==FTSQUERY_AND || eType==FTSQUERY_OR) ){
+      Fts3Expr **apLeaf;
+      apLeaf = (Fts3Expr **)sqlite3_malloc64(sizeof(Fts3Expr *) * nMaxDepth);
+      if( 0==apLeaf ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(apLeaf, 0, sizeof(Fts3Expr *) * nMaxDepth);
+      }
+
+      if( rc==SQLITE_OK ){
+        int i;
+        Fts3Expr *p;
+
+        /* Set $p to point to the left-most leaf in the tree of eType nodes. */
+        for(p=pRoot; p->eType==eType; p=p->pLeft){
+          assert( p->pParent==0 || p->pParent->pLeft==p );
+          assert( p->pLeft && p->pRight );
+        }
+
+        /* This loop runs once for each leaf in the tree of eType nodes. */
+        while( 1 ){
+          int iLvl;
+          Fts3Expr *pParent = p->pParent;     /* Current parent of p */
+
+          assert( pParent==0 || pParent->pLeft==p );
+          p->pParent = 0;
+          if( pParent ){
+            pParent->pLeft = 0;
+          }else{
+            pRoot = 0;
+          }
+          rc = fts3ExprBalance(&p, nMaxDepth-1);
+          if( rc!=SQLITE_OK ) break;
+
+          for(iLvl=0; p && iLvl<nMaxDepth; iLvl++){
+            if( apLeaf[iLvl]==0 ){
+              apLeaf[iLvl] = p;
+              p = 0;
+            }else{
+              assert( pFree );
+              pFree->pLeft = apLeaf[iLvl];
+              pFree->pRight = p;
+              pFree->pLeft->pParent = pFree;
+              pFree->pRight->pParent = pFree;
+
+              p = pFree;
+              pFree = pFree->pParent;
+              p->pParent = 0;
+              apLeaf[iLvl] = 0;
+            }
+          }
+          if( p ){
+            sqlite3Fts3ExprFree(p);
+            rc = SQLITE_TOOBIG;
+            break;
+          }
+
+          /* If that was the last leaf node, break out of the loop */
+          if( pParent==0 ) break;
+
+          /* Set $p to point to the next leaf in the tree of eType nodes */
+          for(p=pParent->pRight; p->eType==eType; p=p->pLeft);
+
+          /* Remove pParent from the original tree. */
+          assert( pParent->pParent==0 || pParent->pParent->pLeft==pParent );
+          pParent->pRight->pParent = pParent->pParent;
+          if( pParent->pParent ){
+            pParent->pParent->pLeft = pParent->pRight;
+          }else{
+            assert( pParent==pRoot );
+            pRoot = pParent->pRight;
+          }
+
+          /* Link pParent into the free node list. It will be used as an
+          ** internal node of the new tree.  */
+          pParent->pParent = pFree;
+          pFree = pParent;
+        }
+
+        if( rc==SQLITE_OK ){
+          p = 0;
+          for(i=0; i<nMaxDepth; i++){
+            if( apLeaf[i] ){
+              if( p==0 ){
+                p = apLeaf[i];
+                p->pParent = 0;
+              }else{
+                assert( pFree!=0 );
+                pFree->pRight = p;
+                pFree->pLeft = apLeaf[i];
+                pFree->pLeft->pParent = pFree;
+                pFree->pRight->pParent = pFree;
+
+                p = pFree;
+                pFree = pFree->pParent;
+                p->pParent = 0;
+              }
+            }
+          }
+          pRoot = p;
+        }else{
+          /* An error occurred. Delete the contents of the apLeaf[] array
+          ** and pFree list. Everything else is cleaned up by the call to
+          ** sqlite3Fts3ExprFree(pRoot) below.  */
+          Fts3Expr *pDel;
+          for(i=0; i<nMaxDepth; i++){
+            sqlite3Fts3ExprFree(apLeaf[i]);
+          }
+          while( (pDel=pFree)!=0 ){
+            pFree = pDel->pParent;
+            sqlite3_free(pDel);
+          }
+        }
+
+        assert( pFree==0 );
+        sqlite3_free( apLeaf );
+      }
+    }else if( eType==FTSQUERY_NOT ){
+      Fts3Expr *pLeft = pRoot->pLeft;
+      Fts3Expr *pRight = pRoot->pRight;
+
+      pRoot->pLeft = 0;
+      pRoot->pRight = 0;
+      pLeft->pParent = 0;
+      pRight->pParent = 0;
+
+      rc = fts3ExprBalance(&pLeft, nMaxDepth-1);
+      if( rc==SQLITE_OK ){
+        rc = fts3ExprBalance(&pRight, nMaxDepth-1);
+      }
+
+      if( rc!=SQLITE_OK ){
+        sqlite3Fts3ExprFree(pRight);
+        sqlite3Fts3ExprFree(pLeft);
+      }else{
+        assert( pLeft && pRight );
+        pRoot->pLeft = pLeft;
+        pLeft->pParent = pRoot;
+        pRoot->pRight = pRight;
+        pRight->pParent = pRoot;
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3Fts3ExprFree(pRoot);
+    pRoot = 0;
+  }
+  *pp = pRoot;
+  return rc;
+}
+
+/*
+** This function is similar to sqlite3Fts3ExprParse(), with the following
+** differences:
+**
+**   1. It does not do expression rebalancing.
+**   2. It does not check that the expression does not exceed the
+**      maximum allowable depth.
+**   3. Even if it fails, *ppExpr may still be set to point to an
+**      expression tree. It should be deleted using sqlite3Fts3ExprFree()
+**      in this case.
+*/
+static int fts3ExprParseUnbalanced(
+  sqlite3_tokenizer *pTokenizer,      /* Tokenizer module */
+  int iLangid,                        /* Language id for tokenizer */
+  char **azCol,                       /* Array of column names for fts3 table */
+  int bFts4,                          /* True to allow FTS4-only syntax */
+  int nCol,                           /* Number of entries in azCol[] */
+  int iDefaultCol,                    /* Default column to query */
+  const char *z, int n,               /* Text of MATCH query */
+  Fts3Expr **ppExpr                   /* OUT: Parsed query structure */
+){
+  int nParsed;
+  int rc;
+  ParseContext sParse;
+
+  memset(&sParse, 0, sizeof(ParseContext));
+  sParse.pTokenizer = pTokenizer;
+  sParse.iLangid = iLangid;
+  sParse.azCol = (const char **)azCol;
+  sParse.nCol = nCol;
+  sParse.iDefaultCol = iDefaultCol;
+  sParse.bFts4 = bFts4;
+  if( z==0 ){
+    *ppExpr = 0;
+    return SQLITE_OK;
+  }
+  if( n<0 ){
+    n = (int)strlen(z);
+  }
+  rc = fts3ExprParse(&sParse, z, n, ppExpr, &nParsed);
+  assert( rc==SQLITE_OK || *ppExpr==0 );
+
+  /* Check for mismatched parenthesis */
+  if( rc==SQLITE_OK && sParse.nNest ){
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+/*
+** Parameters z and n contain a pointer to and length of a buffer containing
+** an fts3 query expression, respectively. This function attempts to parse the
+** query expression and create a tree of Fts3Expr structures representing the
+** parsed expression. If successful, *ppExpr is set to point to the head
+** of the parsed expression tree and SQLITE_OK is returned. If an error
+** occurs, either SQLITE_NOMEM (out-of-memory error) or SQLITE_ERROR (parse
+** error) is returned and *ppExpr is set to 0.
+**
+** If parameter n is a negative number, then z is assumed to point to a
+** nul-terminated string and the length is determined using strlen().
+**
+** The first parameter, pTokenizer, is passed the fts3 tokenizer module to
+** use to normalize query tokens while parsing the expression. The azCol[]
+** array, which is assumed to contain nCol entries, should contain the names
+** of each column in the target fts3 table, in order from left to right.
+** Column names must be nul-terminated strings.
+**
+** The iDefaultCol parameter should be passed the index of the table column
+** that appears on the left-hand-side of the MATCH operator (the default
+** column to match against for tokens for which a column name is not explicitly
+** specified as part of the query string), or -1 if tokens may by default
+** match any table column.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ExprParse(
+  sqlite3_tokenizer *pTokenizer,      /* Tokenizer module */
+  int iLangid,                        /* Language id for tokenizer */
+  char **azCol,                       /* Array of column names for fts3 table */
+  int bFts4,                          /* True to allow FTS4-only syntax */
+  int nCol,                           /* Number of entries in azCol[] */
+  int iDefaultCol,                    /* Default column to query */
+  const char *z, int n,               /* Text of MATCH query */
+  Fts3Expr **ppExpr,                  /* OUT: Parsed query structure */
+  char **pzErr                        /* OUT: Error message (sqlite3_malloc) */
+){
+  int rc = fts3ExprParseUnbalanced(
+      pTokenizer, iLangid, azCol, bFts4, nCol, iDefaultCol, z, n, ppExpr
+  );
+
+  /* Rebalance the expression. And check that its depth does not exceed
+  ** SQLITE_FTS3_MAX_EXPR_DEPTH.  */
+  if( rc==SQLITE_OK && *ppExpr ){
+    rc = fts3ExprBalance(ppExpr, SQLITE_FTS3_MAX_EXPR_DEPTH);
+    if( rc==SQLITE_OK ){
+      rc = fts3ExprCheckDepth(*ppExpr, SQLITE_FTS3_MAX_EXPR_DEPTH);
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3Fts3ExprFree(*ppExpr);
+    *ppExpr = 0;
+    if( rc==SQLITE_TOOBIG ){
+      sqlite3Fts3ErrMsg(pzErr,
+          "FTS expression tree is too large (maximum depth %d)",
+          SQLITE_FTS3_MAX_EXPR_DEPTH
+      );
+      rc = SQLITE_ERROR;
+    }else if( rc==SQLITE_ERROR ){
+      sqlite3Fts3ErrMsg(pzErr, "malformed MATCH expression: [%s]", z);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Free a single node of an expression tree.
+*/
+static void fts3FreeExprNode(Fts3Expr *p){
+  assert( p->eType==FTSQUERY_PHRASE || p->pPhrase==0 );
+  sqlite3Fts3EvalPhraseCleanup(p->pPhrase);
+  sqlite3_free(p->aMI);
+  sqlite3_free(p);
+}
+
+/*
+** Free a parsed fts3 query expression allocated by sqlite3Fts3ExprParse().
+**
+** This function would be simpler if it recursively called itself. But
+** that would mean passing a sufficiently large expression to ExprParse()
+** could cause a stack overflow.
+*/
+SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *pDel){
+  Fts3Expr *p;
+  assert( pDel==0 || pDel->pParent==0 );
+  for(p=pDel; p && (p->pLeft||p->pRight); p=(p->pLeft ? p->pLeft : p->pRight)){
+    assert( p->pParent==0 || p==p->pParent->pRight || p==p->pParent->pLeft );
+  }
+  while( p ){
+    Fts3Expr *pParent = p->pParent;
+    fts3FreeExprNode(p);
+    if( pParent && p==pParent->pLeft && pParent->pRight ){
+      p = pParent->pRight;
+      while( p && (p->pLeft || p->pRight) ){
+        assert( p==p->pParent->pRight || p==p->pParent->pLeft );
+        p = (p->pLeft ? p->pLeft : p->pRight);
+      }
+    }else{
+      p = pParent;
+    }
+  }
+}
+
+/****************************************************************************
+*****************************************************************************
+** Everything after this point is just test code.
+*/
+
+#ifdef SQLITE_TEST
+
+/* #include <stdio.h> */
+
+/*
+** Return a pointer to a buffer containing a text representation of the
+** expression passed as the first argument. The buffer is obtained from
+** sqlite3_malloc(). It is the responsibility of the caller to use
+** sqlite3_free() to release the memory. If an OOM condition is encountered,
+** NULL is returned.
+**
+** If the second argument is not NULL, then its contents are prepended to
+** the returned expression text and then freed using sqlite3_free().
+*/
+static char *exprToString(Fts3Expr *pExpr, char *zBuf){
+  if( pExpr==0 ){
+    return sqlite3_mprintf("");
+  }
+  switch( pExpr->eType ){
+    case FTSQUERY_PHRASE: {
+      Fts3Phrase *pPhrase = pExpr->pPhrase;
+      int i;
+      zBuf = sqlite3_mprintf(
+          "%zPHRASE %d 0", zBuf, pPhrase->iColumn);
+      for(i=0; zBuf && i<pPhrase->nToken; i++){
+        zBuf = sqlite3_mprintf("%z %.*s%s", zBuf,
+            pPhrase->aToken[i].n, pPhrase->aToken[i].z,
+            (pPhrase->aToken[i].isPrefix?"+":"")
+        );
+      }
+      return zBuf;
+    }
+
+    case FTSQUERY_NEAR:
+      zBuf = sqlite3_mprintf("%zNEAR/%d ", zBuf, pExpr->nNear);
+      break;
+    case FTSQUERY_NOT:
+      zBuf = sqlite3_mprintf("%zNOT ", zBuf);
+      break;
+    case FTSQUERY_AND:
+      zBuf = sqlite3_mprintf("%zAND ", zBuf);
+      break;
+    case FTSQUERY_OR:
+      zBuf = sqlite3_mprintf("%zOR ", zBuf);
+      break;
+  }
+
+  if( zBuf ) zBuf = sqlite3_mprintf("%z{", zBuf);
+  if( zBuf ) zBuf = exprToString(pExpr->pLeft, zBuf);
+  if( zBuf ) zBuf = sqlite3_mprintf("%z} {", zBuf);
+
+  if( zBuf ) zBuf = exprToString(pExpr->pRight, zBuf);
+  if( zBuf ) zBuf = sqlite3_mprintf("%z}", zBuf);
+
+  return zBuf;
+}
+
+/*
+** This is the implementation of a scalar SQL function used to test the
+** expression parser. It should be called as follows:
+**
+**   fts3_exprtest(<tokenizer>, <expr>, <column 1>, ...);
+**
+** The first argument, <tokenizer>, is the name of the fts3 tokenizer used
+** to parse the query expression (see README.tokenizers). The second argument
+** is the query expression to parse. Each subsequent argument is the name
+** of a column of the fts3 table that the query expression may refer to.
+** For example:
+**
+**   SELECT fts3_exprtest('simple', 'Bill col2:Bloggs', 'col1', 'col2');
+*/
+static void fts3ExprTestCommon(
+  int bRebalance,
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_tokenizer *pTokenizer = 0;
+  int rc;
+  char **azCol = 0;
+  const char *zExpr;
+  int nExpr;
+  int nCol;
+  int ii;
+  Fts3Expr *pExpr;
+  char *zBuf = 0;
+  Fts3Hash *pHash = (Fts3Hash*)sqlite3_user_data(context);
+  const char *zTokenizer = 0;
+  char *zErr = 0;
+
+  if( argc<3 ){
+    sqlite3_result_error(context,
+        "Usage: fts3_exprtest(tokenizer, expr, col1, ...", -1
+    );
+    return;
+  }
+
+  zTokenizer = (const char*)sqlite3_value_text(argv[0]);
+  rc = sqlite3Fts3InitTokenizer(pHash, zTokenizer, &pTokenizer, &zErr);
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM ){
+      sqlite3_result_error_nomem(context);
+    }else{
+      sqlite3_result_error(context, zErr, -1);
+    }
+    sqlite3_free(zErr);
+    return;
+  }
+
+  zExpr = (const char *)sqlite3_value_text(argv[1]);
+  nExpr = sqlite3_value_bytes(argv[1]);
+  nCol = argc-2;
+  azCol = (char **)sqlite3_malloc64(nCol*sizeof(char *));
+  if( !azCol ){
+    sqlite3_result_error_nomem(context);
+    goto exprtest_out;
+  }
+  for(ii=0; ii<nCol; ii++){
+    azCol[ii] = (char *)sqlite3_value_text(argv[ii+2]);
+  }
+
+  if( bRebalance ){
+    char *zDummy = 0;
+    rc = sqlite3Fts3ExprParse(
+        pTokenizer, 0, azCol, 0, nCol, nCol, zExpr, nExpr, &pExpr, &zDummy
+    );
+    assert( rc==SQLITE_OK || pExpr==0 );
+    sqlite3_free(zDummy);
+  }else{
+    rc = fts3ExprParseUnbalanced(
+        pTokenizer, 0, azCol, 0, nCol, nCol, zExpr, nExpr, &pExpr
+    );
+  }
+
+  if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM ){
+    sqlite3Fts3ExprFree(pExpr);
+    sqlite3_result_error(context, "Error parsing expression", -1);
+  }else if( rc==SQLITE_NOMEM || !(zBuf = exprToString(pExpr, 0)) ){
+    sqlite3_result_error_nomem(context);
+  }else{
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+    sqlite3_free(zBuf);
+  }
+
+  sqlite3Fts3ExprFree(pExpr);
+
+exprtest_out:
+  if( pTokenizer ){
+    rc = pTokenizer->pModule->xDestroy(pTokenizer);
+  }
+  sqlite3_free(azCol);
+}
+
+static void fts3ExprTest(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  fts3ExprTestCommon(0, context, argc, argv);
+}
+static void fts3ExprTestRebalance(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  fts3ExprTestCommon(1, context, argc, argv);
+}
+
+/*
+** Register the query expression parser test function fts3_exprtest()
+** with database connection db.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ExprInitTestInterface(sqlite3 *db, Fts3Hash *pHash){
+  int rc = sqlite3_create_function(
+      db, "fts3_exprtest", -1, SQLITE_UTF8, (void*)pHash, fts3ExprTest, 0, 0
+  );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(db, "fts3_exprtest_rebalance",
+        -1, SQLITE_UTF8, (void*)pHash, fts3ExprTestRebalance, 0, 0
+    );
+  }
+  return rc;
+}
+
+#endif
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_expr.c *******************************************/
+/************** Begin file fts3_hash.c ***************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the implementation of generic hash-tables used in SQLite.
+** We've modified it slightly to serve as a standalone hash table
+** implementation for the full-text indexing module.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <string.h> */
+
+/* #include "fts3_hash.h" */
+
+/*
+** Malloc and Free functions
+*/
+static void *fts3HashMalloc(sqlite3_int64 n){
+  void *p = sqlite3_malloc64(n);
+  if( p ){
+    memset(p, 0, n);
+  }
+  return p;
+}
+static void fts3HashFree(void *p){
+  sqlite3_free(p);
+}
+
+/* Turn bulk memory into a hash table object by initializing the
+** fields of the Hash structure.
+**
+** "pNew" is a pointer to the hash table that is to be initialized.
+** keyClass is one of the constants
+** FTS3_HASH_BINARY or FTS3_HASH_STRING.  The value of keyClass
+** determines what kind of key the hash table will use.  "copyKey" is
+** true if the hash table should make its own private copy of keys and
+** false if it should just use the supplied pointer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashInit(Fts3Hash *pNew, char keyClass, char copyKey){
+  assert( pNew!=0 );
+  assert( keyClass>=FTS3_HASH_STRING && keyClass<=FTS3_HASH_BINARY );
+  pNew->keyClass = keyClass;
+  pNew->copyKey = copyKey;
+  pNew->first = 0;
+  pNew->count = 0;
+  pNew->htsize = 0;
+  pNew->ht = 0;
+}
+
+/* Remove all entries from a hash table.  Reclaim all memory.
+** Call this routine to delete a hash table or to reset a hash table
+** to the empty state.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashClear(Fts3Hash *pH){
+  Fts3HashElem *elem;         /* For looping over all elements of the table */
+
+  assert( pH!=0 );
+  elem = pH->first;
+  pH->first = 0;
+  fts3HashFree(pH->ht);
+  pH->ht = 0;
+  pH->htsize = 0;
+  while( elem ){
+    Fts3HashElem *next_elem = elem->next;
+    if( pH->copyKey && elem->pKey ){
+      fts3HashFree(elem->pKey);
+    }
+    fts3HashFree(elem);
+    elem = next_elem;
+  }
+  pH->count = 0;
+}
+
+/*
+** Hash and comparison functions when the mode is FTS3_HASH_STRING
+*/
+static int fts3StrHash(const void *pKey, int nKey){
+  const char *z = (const char *)pKey;
+  unsigned h = 0;
+  if( nKey<=0 ) nKey = (int) strlen(z);
+  while( nKey > 0  ){
+    h = (h<<3) ^ h ^ *z++;
+    nKey--;
+  }
+  return (int)(h & 0x7fffffff);
+}
+static int fts3StrCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  if( n1!=n2 ) return 1;
+  return strncmp((const char*)pKey1,(const char*)pKey2,n1);
+}
+
+/*
+** Hash and comparison functions when the mode is FTS3_HASH_BINARY
+*/
+static int fts3BinHash(const void *pKey, int nKey){
+  int h = 0;
+  const char *z = (const char *)pKey;
+  while( nKey-- > 0 ){
+    h = (h<<3) ^ h ^ *(z++);
+  }
+  return h & 0x7fffffff;
+}
+static int fts3BinCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  if( n1!=n2 ) return 1;
+  return memcmp(pKey1,pKey2,n1);
+}
+
+/*
+** Return a pointer to the appropriate hash function given the key class.
+**
+** The C syntax in this function definition may be unfamilar to some
+** programmers, so we provide the following additional explanation:
+**
+** The name of the function is "ftsHashFunction".  The function takes a
+** single parameter "keyClass".  The return value of ftsHashFunction()
+** is a pointer to another function.  Specifically, the return value
+** of ftsHashFunction() is a pointer to a function that takes two parameters
+** with types "const void*" and "int" and returns an "int".
+*/
+static int (*ftsHashFunction(int keyClass))(const void*,int){
+  if( keyClass==FTS3_HASH_STRING ){
+    return &fts3StrHash;
+  }else{
+    assert( keyClass==FTS3_HASH_BINARY );
+    return &fts3BinHash;
+  }
+}
+
+/*
+** Return a pointer to the appropriate hash function given the key class.
+**
+** For help in interpreted the obscure C code in the function definition,
+** see the header comment on the previous function.
+*/
+static int (*ftsCompareFunction(int keyClass))(const void*,int,const void*,int){
+  if( keyClass==FTS3_HASH_STRING ){
+    return &fts3StrCompare;
+  }else{
+    assert( keyClass==FTS3_HASH_BINARY );
+    return &fts3BinCompare;
+  }
+}
+
+/* Link an element into the hash table
+*/
+static void fts3HashInsertElement(
+  Fts3Hash *pH,            /* The complete hash table */
+  struct _fts3ht *pEntry,  /* The entry into which pNew is inserted */
+  Fts3HashElem *pNew       /* The element to be inserted */
+){
+  Fts3HashElem *pHead;     /* First element already in pEntry */
+  pHead = pEntry->chain;
+  if( pHead ){
+    pNew->next = pHead;
+    pNew->prev = pHead->prev;
+    if( pHead->prev ){ pHead->prev->next = pNew; }
+    else             { pH->first = pNew; }
+    pHead->prev = pNew;
+  }else{
+    pNew->next = pH->first;
+    if( pH->first ){ pH->first->prev = pNew; }
+    pNew->prev = 0;
+    pH->first = pNew;
+  }
+  pEntry->count++;
+  pEntry->chain = pNew;
+}
+
+
+/* Resize the hash table so that it cantains "new_size" buckets.
+** "new_size" must be a power of 2.  The hash table might fail
+** to resize if sqliteMalloc() fails.
+**
+** Return non-zero if a memory allocation error occurs.
+*/
+static int fts3Rehash(Fts3Hash *pH, int new_size){
+  struct _fts3ht *new_ht;          /* The new hash table */
+  Fts3HashElem *elem, *next_elem;  /* For looping over existing elements */
+  int (*xHash)(const void*,int);   /* The hash function */
+
+  assert( (new_size & (new_size-1))==0 );
+  new_ht = (struct _fts3ht *)fts3HashMalloc( new_size*sizeof(struct _fts3ht) );
+  if( new_ht==0 ) return 1;
+  fts3HashFree(pH->ht);
+  pH->ht = new_ht;
+  pH->htsize = new_size;
+  xHash = ftsHashFunction(pH->keyClass);
+  for(elem=pH->first, pH->first=0; elem; elem = next_elem){
+    int h = (*xHash)(elem->pKey, elem->nKey) & (new_size-1);
+    next_elem = elem->next;
+    fts3HashInsertElement(pH, &new_ht[h], elem);
+  }
+  return 0;
+}
+
+/* This function (for internal use only) locates an element in an
+** hash table that matches the given key.  The hash for this key has
+** already been computed and is passed as the 4th parameter.
+*/
+static Fts3HashElem *fts3FindElementByHash(
+  const Fts3Hash *pH, /* The pH to be searched */
+  const void *pKey,   /* The key we are searching for */
+  int nKey,
+  int h               /* The hash for this key. */
+){
+  Fts3HashElem *elem;            /* Used to loop thru the element list */
+  int count;                     /* Number of elements left to test */
+  int (*xCompare)(const void*,int,const void*,int);  /* comparison function */
+
+  if( pH->ht ){
+    struct _fts3ht *pEntry = &pH->ht[h];
+    elem = pEntry->chain;
+    count = pEntry->count;
+    xCompare = ftsCompareFunction(pH->keyClass);
+    while( count-- && elem ){
+      if( (*xCompare)(elem->pKey,elem->nKey,pKey,nKey)==0 ){
+        return elem;
+      }
+      elem = elem->next;
+    }
+  }
+  return 0;
+}
+
+/* Remove a single entry from the hash table given a pointer to that
+** element and a hash on the element's key.
+*/
+static void fts3RemoveElementByHash(
+  Fts3Hash *pH,         /* The pH containing "elem" */
+  Fts3HashElem* elem,   /* The element to be removed from the pH */
+  int h                 /* Hash value for the element */
+){
+  struct _fts3ht *pEntry;
+  if( elem->prev ){
+    elem->prev->next = elem->next;
+  }else{
+    pH->first = elem->next;
+  }
+  if( elem->next ){
+    elem->next->prev = elem->prev;
+  }
+  pEntry = &pH->ht[h];
+  if( pEntry->chain==elem ){
+    pEntry->chain = elem->next;
+  }
+  pEntry->count--;
+  if( pEntry->count<=0 ){
+    pEntry->chain = 0;
+  }
+  if( pH->copyKey && elem->pKey ){
+    fts3HashFree(elem->pKey);
+  }
+  fts3HashFree( elem );
+  pH->count--;
+  if( pH->count<=0 ){
+    assert( pH->first==0 );
+    assert( pH->count==0 );
+    fts3HashClear(pH);
+  }
+}
+
+SQLITE_PRIVATE Fts3HashElem *sqlite3Fts3HashFindElem(
+  const Fts3Hash *pH,
+  const void *pKey,
+  int nKey
+){
+  int h;                          /* A hash on key */
+  int (*xHash)(const void*,int);  /* The hash function */
+
+  if( pH==0 || pH->ht==0 ) return 0;
+  xHash = ftsHashFunction(pH->keyClass);
+  assert( xHash!=0 );
+  h = (*xHash)(pKey,nKey);
+  assert( (pH->htsize & (pH->htsize-1))==0 );
+  return fts3FindElementByHash(pH,pKey,nKey, h & (pH->htsize-1));
+}
+
+/*
+** Attempt to locate an element of the hash table pH with a key
+** that matches pKey,nKey.  Return the data for this element if it is
+** found, or NULL if there is no match.
+*/
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const Fts3Hash *pH, const void *pKey, int nKey){
+  Fts3HashElem *pElem;            /* The element that matches key (if any) */
+
+  pElem = sqlite3Fts3HashFindElem(pH, pKey, nKey);
+  return pElem ? pElem->data : 0;
+}
+
+/* Insert an element into the hash table pH.  The key is pKey,nKey
+** and the data is "data".
+**
+** If no element exists with a matching key, then a new
+** element is created.  A copy of the key is made if the copyKey
+** flag is set.  NULL is returned.
+**
+** If another element already exists with the same key, then the
+** new data replaces the old data and the old data is returned.
+** The key is not copied in this instance.  If a malloc fails, then
+** the new data is returned and the hash table is unchanged.
+**
+** If the "data" parameter to this function is NULL, then the
+** element corresponding to "key" is removed from the hash table.
+*/
+SQLITE_PRIVATE void *sqlite3Fts3HashInsert(
+  Fts3Hash *pH,        /* The hash table to insert into */
+  const void *pKey,    /* The key */
+  int nKey,            /* Number of bytes in the key */
+  void *data           /* The data */
+){
+  int hraw;                 /* Raw hash value of the key */
+  int h;                    /* the hash of the key modulo hash table size */
+  Fts3HashElem *elem;       /* Used to loop thru the element list */
+  Fts3HashElem *new_elem;   /* New element added to the pH */
+  int (*xHash)(const void*,int);  /* The hash function */
+
+  assert( pH!=0 );
+  xHash = ftsHashFunction(pH->keyClass);
+  assert( xHash!=0 );
+  hraw = (*xHash)(pKey, nKey);
+  assert( (pH->htsize & (pH->htsize-1))==0 );
+  h = hraw & (pH->htsize-1);
+  elem = fts3FindElementByHash(pH,pKey,nKey,h);
+  if( elem ){
+    void *old_data = elem->data;
+    if( data==0 ){
+      fts3RemoveElementByHash(pH,elem,h);
+    }else{
+      elem->data = data;
+    }
+    return old_data;
+  }
+  if( data==0 ) return 0;
+  if( (pH->htsize==0 && fts3Rehash(pH,8))
+   || (pH->count>=pH->htsize && fts3Rehash(pH, pH->htsize*2))
+  ){
+    pH->count = 0;
+    return data;
+  }
+  assert( pH->htsize>0 );
+  new_elem = (Fts3HashElem*)fts3HashMalloc( sizeof(Fts3HashElem) );
+  if( new_elem==0 ) return data;
+  if( pH->copyKey && pKey!=0 ){
+    new_elem->pKey = fts3HashMalloc( nKey );
+    if( new_elem->pKey==0 ){
+      fts3HashFree(new_elem);
+      return data;
+    }
+    memcpy((void*)new_elem->pKey, pKey, nKey);
+  }else{
+    new_elem->pKey = (void*)pKey;
+  }
+  new_elem->nKey = nKey;
+  pH->count++;
+  assert( pH->htsize>0 );
+  assert( (pH->htsize & (pH->htsize-1))==0 );
+  h = hraw & (pH->htsize-1);
+  fts3HashInsertElement(pH, &pH->ht[h], new_elem);
+  new_elem->data = data;
+  return 0;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_hash.c *******************************************/
+/************** Begin file fts3_porter.c *************************************/
+/*
+** 2006 September 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Implementation of the full-text-search tokenizer that implements
+** a Porter stemmer.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+
+/* #include "fts3_tokenizer.h" */
+
+/*
+** Class derived from sqlite3_tokenizer
+*/
+typedef struct porter_tokenizer {
+  sqlite3_tokenizer base;      /* Base class */
+} porter_tokenizer;
+
+/*
+** Class derived from sqlite3_tokenizer_cursor
+*/
+typedef struct porter_tokenizer_cursor {
+  sqlite3_tokenizer_cursor base;
+  const char *zInput;          /* input we are tokenizing */
+  int nInput;                  /* size of the input */
+  int iOffset;                 /* current position in zInput */
+  int iToken;                  /* index of next token to be returned */
+  char *zToken;                /* storage for current token */
+  int nAllocated;              /* space allocated to zToken buffer */
+} porter_tokenizer_cursor;
+
+
+/*
+** Create a new tokenizer instance.
+*/
+static int porterCreate(
+  int argc, const char * const *argv,
+  sqlite3_tokenizer **ppTokenizer
+){
+  porter_tokenizer *t;
+
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+
+  t = (porter_tokenizer *) sqlite3_malloc(sizeof(*t));
+  if( t==NULL ) return SQLITE_NOMEM;
+  memset(t, 0, sizeof(*t));
+  *ppTokenizer = &t->base;
+  return SQLITE_OK;
+}
+
+/*
+** Destroy a tokenizer
+*/
+static int porterDestroy(sqlite3_tokenizer *pTokenizer){
+  sqlite3_free(pTokenizer);
+  return SQLITE_OK;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is zInput[0..nInput-1].  A cursor
+** used to incrementally tokenize this string is returned in
+** *ppCursor.
+*/
+static int porterOpen(
+  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
+  const char *zInput, int nInput,        /* String to be tokenized */
+  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
+){
+  porter_tokenizer_cursor *c;
+
+  UNUSED_PARAMETER(pTokenizer);
+
+  c = (porter_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
+  if( c==NULL ) return SQLITE_NOMEM;
+
+  c->zInput = zInput;
+  if( zInput==0 ){
+    c->nInput = 0;
+  }else if( nInput<0 ){
+    c->nInput = (int)strlen(zInput);
+  }else{
+    c->nInput = nInput;
+  }
+  c->iOffset = 0;                 /* start tokenizing at the beginning */
+  c->iToken = 0;
+  c->zToken = NULL;               /* no space allocated, yet. */
+  c->nAllocated = 0;
+
+  *ppCursor = &c->base;
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to
+** porterOpen() above.
+*/
+static int porterClose(sqlite3_tokenizer_cursor *pCursor){
+  porter_tokenizer_cursor *c = (porter_tokenizer_cursor *) pCursor;
+  sqlite3_free(c->zToken);
+  sqlite3_free(c);
+  return SQLITE_OK;
+}
+/*
+** Vowel or consonant
+*/
+static const char cType[] = {
+   0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0,
+   1, 1, 1, 2, 1
+};
+
+/*
+** isConsonant() and isVowel() determine if their first character in
+** the string they point to is a consonant or a vowel, according
+** to Porter ruls.
+**
+** A consonate is any letter other than 'a', 'e', 'i', 'o', or 'u'.
+** 'Y' is a consonant unless it follows another consonant,
+** in which case it is a vowel.
+**
+** In these routine, the letters are in reverse order.  So the 'y' rule
+** is that 'y' is a consonant unless it is followed by another
+** consonent.
+*/
+static int isVowel(const char*);
+static int isConsonant(const char *z){
+  int j;
+  char x = *z;
+  if( x==0 ) return 0;
+  assert( x>='a' && x<='z' );
+  j = cType[x-'a'];
+  if( j<2 ) return j;
+  return z[1]==0 || isVowel(z + 1);
+}
+static int isVowel(const char *z){
+  int j;
+  char x = *z;
+  if( x==0 ) return 0;
+  assert( x>='a' && x<='z' );
+  j = cType[x-'a'];
+  if( j<2 ) return 1-j;
+  return isConsonant(z + 1);
+}
+
+/*
+** Let any sequence of one or more vowels be represented by V and let
+** C be sequence of one or more consonants.  Then every word can be
+** represented as:
+**
+**           [C] (VC){m} [V]
+**
+** In prose:  A word is an optional consonant followed by zero or
+** vowel-consonant pairs followed by an optional vowel.  "m" is the
+** number of vowel consonant pairs.  This routine computes the value
+** of m for the first i bytes of a word.
+**
+** Return true if the m-value for z is 1 or more.  In other words,
+** return true if z contains at least one vowel that is followed
+** by a consonant.
+**
+** In this routine z[] is in reverse order.  So we are really looking
+** for an instance of a consonant followed by a vowel.
+*/
+static int m_gt_0(const char *z){
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  return *z!=0;
+}
+
+/* Like mgt0 above except we are looking for a value of m which is
+** exactly 1
+*/
+static int m_eq_1(const char *z){
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 1;
+  while( isConsonant(z) ){ z++; }
+  return *z==0;
+}
+
+/* Like mgt0 above except we are looking for a value of m>1 instead
+** or m>0
+*/
+static int m_gt_1(const char *z){
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  return *z!=0;
+}
+
+/*
+** Return TRUE if there is a vowel anywhere within z[0..n-1]
+*/
+static int hasVowel(const char *z){
+  while( isConsonant(z) ){ z++; }
+  return *z!=0;
+}
+
+/*
+** Return TRUE if the word ends in a double consonant.
+**
+** The text is reversed here. So we are really looking at
+** the first two characters of z[].
+*/
+static int doubleConsonant(const char *z){
+  return isConsonant(z) && z[0]==z[1];
+}
+
+/*
+** Return TRUE if the word ends with three letters which
+** are consonant-vowel-consonent and where the final consonant
+** is not 'w', 'x', or 'y'.
+**
+** The word is reversed here.  So we are really checking the
+** first three letters and the first one cannot be in [wxy].
+*/
+static int star_oh(const char *z){
+  return
+    isConsonant(z) &&
+    z[0]!='w' && z[0]!='x' && z[0]!='y' &&
+    isVowel(z+1) &&
+    isConsonant(z+2);
+}
+
+/*
+** If the word ends with zFrom and xCond() is true for the stem
+** of the word that preceeds the zFrom ending, then change the
+** ending to zTo.
+**
+** The input word *pz and zFrom are both in reverse order.  zTo
+** is in normal order.
+**
+** Return TRUE if zFrom matches.  Return FALSE if zFrom does not
+** match.  Not that TRUE is returned even if xCond() fails and
+** no substitution occurs.
+*/
+static int stem(
+  char **pz,             /* The word being stemmed (Reversed) */
+  const char *zFrom,     /* If the ending matches this... (Reversed) */
+  const char *zTo,       /* ... change the ending to this (not reversed) */
+  int (*xCond)(const char*)   /* Condition that must be true */
+){
+  char *z = *pz;
+  while( *zFrom && *zFrom==*z ){ z++; zFrom++; }
+  if( *zFrom!=0 ) return 0;
+  if( xCond && !xCond(z) ) return 1;
+  while( *zTo ){
+    *(--z) = *(zTo++);
+  }
+  *pz = z;
+  return 1;
+}
+
+/*
+** This is the fallback stemmer used when the porter stemmer is
+** inappropriate.  The input word is copied into the output with
+** US-ASCII case folding.  If the input word is too long (more
+** than 20 bytes if it contains no digits or more than 6 bytes if
+** it contains digits) then word is truncated to 20 or 6 bytes
+** by taking 10 or 3 bytes from the beginning and end.
+*/
+static void copy_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
+  int i, mx, j;
+  int hasDigit = 0;
+  for(i=0; i<nIn; i++){
+    char c = zIn[i];
+    if( c>='A' && c<='Z' ){
+      zOut[i] = c - 'A' + 'a';
+    }else{
+      if( c>='0' && c<='9' ) hasDigit = 1;
+      zOut[i] = c;
+    }
+  }
+  mx = hasDigit ? 3 : 10;
+  if( nIn>mx*2 ){
+    for(j=mx, i=nIn-mx; i<nIn; i++, j++){
+      zOut[j] = zOut[i];
+    }
+    i = j;
+  }
+  zOut[i] = 0;
+  *pnOut = i;
+}
+
+
+/*
+** Stem the input word zIn[0..nIn-1].  Store the output in zOut.
+** zOut is at least big enough to hold nIn bytes.  Write the actual
+** size of the output word (exclusive of the '\0' terminator) into *pnOut.
+**
+** Any upper-case characters in the US-ASCII character set ([A-Z])
+** are converted to lower case.  Upper-case UTF characters are
+** unchanged.
+**
+** Words that are longer than about 20 bytes are stemmed by retaining
+** a few bytes from the beginning and the end of the word.  If the
+** word contains digits, 3 bytes are taken from the beginning and
+** 3 bytes from the end.  For long words without digits, 10 bytes
+** are taken from each end.  US-ASCII case folding still applies.
+**
+** If the input word contains not digits but does characters not
+** in [a-zA-Z] then no stemming is attempted and this routine just
+** copies the input into the input into the output with US-ASCII
+** case folding.
+**
+** Stemming never increases the length of the word.  So there is
+** no chance of overflowing the zOut buffer.
+*/
+static void porter_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
+  int i, j;
+  char zReverse[28];
+  char *z, *z2;
+  if( nIn<3 || nIn>=(int)sizeof(zReverse)-7 ){
+    /* The word is too big or too small for the porter stemmer.
+    ** Fallback to the copy stemmer */
+    copy_stemmer(zIn, nIn, zOut, pnOut);
+    return;
+  }
+  for(i=0, j=sizeof(zReverse)-6; i<nIn; i++, j--){
+    char c = zIn[i];
+    if( c>='A' && c<='Z' ){
+      zReverse[j] = c + 'a' - 'A';
+    }else if( c>='a' && c<='z' ){
+      zReverse[j] = c;
+    }else{
+      /* The use of a character not in [a-zA-Z] means that we fallback
+      ** to the copy stemmer */
+      copy_stemmer(zIn, nIn, zOut, pnOut);
+      return;
+    }
+  }
+  memset(&zReverse[sizeof(zReverse)-5], 0, 5);
+  z = &zReverse[j+1];
+
+
+  /* Step 1a */
+  if( z[0]=='s' ){
+    if(
+     !stem(&z, "sess", "ss", 0) &&
+     !stem(&z, "sei", "i", 0)  &&
+     !stem(&z, "ss", "ss", 0)
+    ){
+      z++;
+    }
+  }
+
+  /* Step 1b */
+  z2 = z;
+  if( stem(&z, "dee", "ee", m_gt_0) ){
+    /* Do nothing.  The work was all in the test */
+  }else if(
+     (stem(&z, "gni", "", hasVowel) || stem(&z, "de", "", hasVowel))
+      && z!=z2
+  ){
+     if( stem(&z, "ta", "ate", 0) ||
+         stem(&z, "lb", "ble", 0) ||
+         stem(&z, "zi", "ize", 0) ){
+       /* Do nothing.  The work was all in the test */
+     }else if( doubleConsonant(z) && (*z!='l' && *z!='s' && *z!='z') ){
+       z++;
+     }else if( m_eq_1(z) && star_oh(z) ){
+       *(--z) = 'e';
+     }
+  }
+
+  /* Step 1c */
+  if( z[0]=='y' && hasVowel(z+1) ){
+    z[0] = 'i';
+  }
+
+  /* Step 2 */
+  switch( z[1] ){
+   case 'a':
+     if( !stem(&z, "lanoita", "ate", m_gt_0) ){
+       stem(&z, "lanoit", "tion", m_gt_0);
+     }
+     break;
+   case 'c':
+     if( !stem(&z, "icne", "ence", m_gt_0) ){
+       stem(&z, "icna", "ance", m_gt_0);
+     }
+     break;
+   case 'e':
+     stem(&z, "rezi", "ize", m_gt_0);
+     break;
+   case 'g':
+     stem(&z, "igol", "log", m_gt_0);
+     break;
+   case 'l':
+     if( !stem(&z, "ilb", "ble", m_gt_0)
+      && !stem(&z, "illa", "al", m_gt_0)
+      && !stem(&z, "iltne", "ent", m_gt_0)
+      && !stem(&z, "ile", "e", m_gt_0)
+     ){
+       stem(&z, "ilsuo", "ous", m_gt_0);
+     }
+     break;
+   case 'o':
+     if( !stem(&z, "noitazi", "ize", m_gt_0)
+      && !stem(&z, "noita", "ate", m_gt_0)
+     ){
+       stem(&z, "rota", "ate", m_gt_0);
+     }
+     break;
+   case 's':
+     if( !stem(&z, "msila", "al", m_gt_0)
+      && !stem(&z, "ssenevi", "ive", m_gt_0)
+      && !stem(&z, "ssenluf", "ful", m_gt_0)
+     ){
+       stem(&z, "ssensuo", "ous", m_gt_0);
+     }
+     break;
+   case 't':
+     if( !stem(&z, "itila", "al", m_gt_0)
+      && !stem(&z, "itivi", "ive", m_gt_0)
+     ){
+       stem(&z, "itilib", "ble", m_gt_0);
+     }
+     break;
+  }
+
+  /* Step 3 */
+  switch( z[0] ){
+   case 'e':
+     if( !stem(&z, "etaci", "ic", m_gt_0)
+      && !stem(&z, "evita", "", m_gt_0)
+     ){
+       stem(&z, "ezila", "al", m_gt_0);
+     }
+     break;
+   case 'i':
+     stem(&z, "itici", "ic", m_gt_0);
+     break;
+   case 'l':
+     if( !stem(&z, "laci", "ic", m_gt_0) ){
+       stem(&z, "luf", "", m_gt_0);
+     }
+     break;
+   case 's':
+     stem(&z, "ssen", "", m_gt_0);
+     break;
+  }
+
+  /* Step 4 */
+  switch( z[1] ){
+   case 'a':
+     if( z[0]=='l' && m_gt_1(z+2) ){
+       z += 2;
+     }
+     break;
+   case 'c':
+     if( z[0]=='e' && z[2]=='n' && (z[3]=='a' || z[3]=='e')  && m_gt_1(z+4)  ){
+       z += 4;
+     }
+     break;
+   case 'e':
+     if( z[0]=='r' && m_gt_1(z+2) ){
+       z += 2;
+     }
+     break;
+   case 'i':
+     if( z[0]=='c' && m_gt_1(z+2) ){
+       z += 2;
+     }
+     break;
+   case 'l':
+     if( z[0]=='e' && z[2]=='b' && (z[3]=='a' || z[3]=='i') && m_gt_1(z+4) ){
+       z += 4;
+     }
+     break;
+   case 'n':
+     if( z[0]=='t' ){
+       if( z[2]=='a' ){
+         if( m_gt_1(z+3) ){
+           z += 3;
+         }
+       }else if( z[2]=='e' ){
+         if( !stem(&z, "tneme", "", m_gt_1)
+          && !stem(&z, "tnem", "", m_gt_1)
+         ){
+           stem(&z, "tne", "", m_gt_1);
+         }
+       }
+     }
+     break;
+   case 'o':
+     if( z[0]=='u' ){
+       if( m_gt_1(z+2) ){
+         z += 2;
+       }
+     }else if( z[3]=='s' || z[3]=='t' ){
+       stem(&z, "noi", "", m_gt_1);
+     }
+     break;
+   case 's':
+     if( z[0]=='m' && z[2]=='i' && m_gt_1(z+3) ){
+       z += 3;
+     }
+     break;
+   case 't':
+     if( !stem(&z, "eta", "", m_gt_1) ){
+       stem(&z, "iti", "", m_gt_1);
+     }
+     break;
+   case 'u':
+     if( z[0]=='s' && z[2]=='o' && m_gt_1(z+3) ){
+       z += 3;
+     }
+     break;
+   case 'v':
+   case 'z':
+     if( z[0]=='e' && z[2]=='i' && m_gt_1(z+3) ){
+       z += 3;
+     }
+     break;
+  }
+
+  /* Step 5a */
+  if( z[0]=='e' ){
+    if( m_gt_1(z+1) ){
+      z++;
+    }else if( m_eq_1(z+1) && !star_oh(z+1) ){
+      z++;
+    }
+  }
+
+  /* Step 5b */
+  if( m_gt_1(z) && z[0]=='l' && z[1]=='l' ){
+    z++;
+  }
+
+  /* z[] is now the stemmed word in reverse order.  Flip it back
+  ** around into forward order and return.
+  */
+  *pnOut = i = (int)strlen(z);
+  zOut[i] = 0;
+  while( *z ){
+    zOut[--i] = *(z++);
+  }
+}
+
+/*
+** Characters that can be part of a token.  We assume any character
+** whose value is greater than 0x80 (any UTF character) can be
+** part of a token.  In other words, delimiters all must have
+** values of 0x7f or lower.
+*/
+static const char porterIdChar[] = {
+/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
+};
+#define isDelim(C) (((ch=C)&0x80)==0 && (ch<0x30 || !porterIdChar[ch-0x30]))
+
+/*
+** Extract the next token from a tokenization cursor.  The cursor must
+** have been opened by a prior call to porterOpen().
+*/
+static int porterNext(
+  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by porterOpen */
+  const char **pzToken,               /* OUT: *pzToken is the token text */
+  int *pnBytes,                       /* OUT: Number of bytes in token */
+  int *piStartOffset,                 /* OUT: Starting offset of token */
+  int *piEndOffset,                   /* OUT: Ending offset of token */
+  int *piPosition                     /* OUT: Position integer of token */
+){
+  porter_tokenizer_cursor *c = (porter_tokenizer_cursor *) pCursor;
+  const char *z = c->zInput;
+
+  while( c->iOffset<c->nInput ){
+    int iStartOffset, ch;
+
+    /* Scan past delimiter characters */
+    while( c->iOffset<c->nInput && isDelim(z[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    /* Count non-delimiter characters. */
+    iStartOffset = c->iOffset;
+    while( c->iOffset<c->nInput && !isDelim(z[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    if( c->iOffset>iStartOffset ){
+      int n = c->iOffset-iStartOffset;
+      if( n>c->nAllocated ){
+        char *pNew;
+        c->nAllocated = n+20;
+        pNew = sqlite3_realloc64(c->zToken, c->nAllocated);
+        if( !pNew ) return SQLITE_NOMEM;
+        c->zToken = pNew;
+      }
+      porter_stemmer(&z[iStartOffset], n, c->zToken, pnBytes);
+      *pzToken = c->zToken;
+      *piStartOffset = iStartOffset;
+      *piEndOffset = c->iOffset;
+      *piPosition = c->iToken++;
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_DONE;
+}
+
+/*
+** The set of routines that implement the porter-stemmer tokenizer
+*/
+static const sqlite3_tokenizer_module porterTokenizerModule = {
+  0,
+  porterCreate,
+  porterDestroy,
+  porterOpen,
+  porterClose,
+  porterNext,
+  0
+};
+
+/*
+** Allocate a new porter tokenizer.  Return a pointer to the new
+** tokenizer in *ppModule
+*/
+SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(
+  sqlite3_tokenizer_module const**ppModule
+){
+  *ppModule = &porterTokenizerModule;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_porter.c *****************************************/
+/************** Begin file fts3_tokenizer.c **********************************/
+/*
+** 2007 June 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is part of an SQLite module implementing full-text search.
+** This particular file implements the generic tokenizer interface.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <string.h> */
+
+/*
+** Return true if the two-argument version of fts3_tokenizer()
+** has been activated via a prior call to sqlite3_db_config(db,
+** SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, 1, 0);
+*/
+static int fts3TokenizerEnabled(sqlite3_context *context){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  int isEnabled = 0;
+  sqlite3_db_config(db,SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER,-1,&isEnabled);
+  return isEnabled;
+}
+
+/*
+** Implementation of the SQL scalar function for accessing the underlying
+** hash table. This function may be called as follows:
+**
+**   SELECT <function-name>(<key-name>);
+**   SELECT <function-name>(<key-name>, <pointer>);
+**
+** where <function-name> is the name passed as the second argument
+** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer').
+**
+** If the <pointer> argument is specified, it must be a blob value
+** containing a pointer to be stored as the hash data corresponding
+** to the string <key-name>. If <pointer> is not specified, then
+** the string <key-name> must already exist in the has table. Otherwise,
+** an error is returned.
+**
+** Whether or not the <pointer> argument is specified, the value returned
+** is a blob containing the pointer stored as the hash data corresponding
+** to string <key-name> (after the hash-table is updated, if applicable).
+*/
+static void fts3TokenizerFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  Fts3Hash *pHash;
+  void *pPtr = 0;
+  const unsigned char *zName;
+  int nName;
+
+  assert( argc==1 || argc==2 );
+
+  pHash = (Fts3Hash *)sqlite3_user_data(context);
+
+  zName = sqlite3_value_text(argv[0]);
+  nName = sqlite3_value_bytes(argv[0])+1;
+
+  if( argc==2 ){
+    if( fts3TokenizerEnabled(context) || sqlite3_value_frombind(argv[1]) ){
+      void *pOld;
+      int n = sqlite3_value_bytes(argv[1]);
+      if( zName==0 || n!=sizeof(pPtr) ){
+        sqlite3_result_error(context, "argument type mismatch", -1);
+        return;
+      }
+      pPtr = *(void **)sqlite3_value_blob(argv[1]);
+      pOld = sqlite3Fts3HashInsert(pHash, (void *)zName, nName, pPtr);
+      if( pOld==pPtr ){
+        sqlite3_result_error(context, "out of memory", -1);
+      }
+    }else{
+      sqlite3_result_error(context, "fts3tokenize disabled", -1);
+      return;
+    }
+  }else{
+    if( zName ){
+      pPtr = sqlite3Fts3HashFind(pHash, zName, nName);
+    }
+    if( !pPtr ){
+      char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
+      sqlite3_result_error(context, zErr, -1);
+      sqlite3_free(zErr);
+      return;
+    }
+  }
+  if( fts3TokenizerEnabled(context) || sqlite3_value_frombind(argv[0]) ){
+    sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT);
+  }
+}
+
+SQLITE_PRIVATE int sqlite3Fts3IsIdChar(char c){
+  static const char isFtsIdChar[] = {
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 0x */
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 1x */
+      0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
+      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
+      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
+  };
+  return (c&0x80 || isFtsIdChar[(int)(c)]);
+}
+
+SQLITE_PRIVATE const char *sqlite3Fts3NextToken(const char *zStr, int *pn){
+  const char *z1;
+  const char *z2 = 0;
+
+  /* Find the start of the next token. */
+  z1 = zStr;
+  while( z2==0 ){
+    char c = *z1;
+    switch( c ){
+      case '\0': return 0;        /* No more tokens here */
+      case '\'':
+      case '"':
+      case '`': {
+        z2 = z1;
+        while( *++z2 && (*z2!=c || *++z2==c) );
+        break;
+      }
+      case '[':
+        z2 = &z1[1];
+        while( *z2 && z2[0]!=']' ) z2++;
+        if( *z2 ) z2++;
+        break;
+
+      default:
+        if( sqlite3Fts3IsIdChar(*z1) ){
+          z2 = &z1[1];
+          while( sqlite3Fts3IsIdChar(*z2) ) z2++;
+        }else{
+          z1++;
+        }
+    }
+  }
+
+  *pn = (int)(z2-z1);
+  return z1;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3InitTokenizer(
+  Fts3Hash *pHash,                /* Tokenizer hash table */
+  const char *zArg,               /* Tokenizer name */
+  sqlite3_tokenizer **ppTok,      /* OUT: Tokenizer (if applicable) */
+  char **pzErr                    /* OUT: Set to malloced error message */
+){
+  int rc;
+  char *z = (char *)zArg;
+  int n = 0;
+  char *zCopy;
+  char *zEnd;                     /* Pointer to nul-term of zCopy */
+  sqlite3_tokenizer_module *m;
+
+  zCopy = sqlite3_mprintf("%s", zArg);
+  if( !zCopy ) return SQLITE_NOMEM;
+  zEnd = &zCopy[strlen(zCopy)];
+
+  z = (char *)sqlite3Fts3NextToken(zCopy, &n);
+  if( z==0 ){
+    assert( n==0 );
+    z = zCopy;
+  }
+  z[n] = '\0';
+  sqlite3Fts3Dequote(z);
+
+  m = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash,z,(int)strlen(z)+1);
+  if( !m ){
+    sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer: %s", z);
+    rc = SQLITE_ERROR;
+  }else{
+    char const **aArg = 0;
+    int iArg = 0;
+    z = &z[n+1];
+    while( z<zEnd && (NULL!=(z = (char *)sqlite3Fts3NextToken(z, &n))) ){
+      sqlite3_int64 nNew = sizeof(char *)*(iArg+1);
+      char const **aNew = (const char **)sqlite3_realloc64((void *)aArg, nNew);
+      if( !aNew ){
+        sqlite3_free(zCopy);
+        sqlite3_free((void *)aArg);
+        return SQLITE_NOMEM;
+      }
+      aArg = aNew;
+      aArg[iArg++] = z;
+      z[n] = '\0';
+      sqlite3Fts3Dequote(z);
+      z = &z[n+1];
+    }
+    rc = m->xCreate(iArg, aArg, ppTok);
+    assert( rc!=SQLITE_OK || *ppTok );
+    if( rc!=SQLITE_OK ){
+      sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer");
+    }else{
+      (*ppTok)->pModule = m;
+    }
+    sqlite3_free((void *)aArg);
+  }
+
+  sqlite3_free(zCopy);
+  return rc;
+}
+
+
+#ifdef SQLITE_TEST
+
+#include "tclsqlite.h"
+/* #include <string.h> */
+
+/*
+** Implementation of a special SQL scalar function for testing tokenizers
+** designed to be used in concert with the Tcl testing framework. This
+** function must be called with two or more arguments:
+**
+**   SELECT <function-name>(<key-name>, ..., <input-string>);
+**
+** where <function-name> is the name passed as the second argument
+** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer')
+** concatenated with the string '_test' (e.g. 'fts3_tokenizer_test').
+**
+** The return value is a string that may be interpreted as a Tcl
+** list. For each token in the <input-string>, three elements are
+** added to the returned list. The first is the token position, the
+** second is the token text (folded, stemmed, etc.) and the third is the
+** substring of <input-string> associated with the token. For example,
+** using the built-in "simple" tokenizer:
+**
+**   SELECT fts_tokenizer_test('simple', 'I don't see how');
+**
+** will return the string:
+**
+**   "{0 i I 1 dont don't 2 see see 3 how how}"
+**
+*/
+static void testFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  Fts3Hash *pHash;
+  sqlite3_tokenizer_module *p;
+  sqlite3_tokenizer *pTokenizer = 0;
+  sqlite3_tokenizer_cursor *pCsr = 0;
+
+  const char *zErr = 0;
+
+  const char *zName;
+  int nName;
+  const char *zInput;
+  int nInput;
+
+  const char *azArg[64];
+
+  const char *zToken;
+  int nToken = 0;
+  int iStart = 0;
+  int iEnd = 0;
+  int iPos = 0;
+  int i;
+
+  Tcl_Obj *pRet;
+
+  if( argc<2 ){
+    sqlite3_result_error(context, "insufficient arguments", -1);
+    return;
+  }
+
+  nName = sqlite3_value_bytes(argv[0]);
+  zName = (const char *)sqlite3_value_text(argv[0]);
+  nInput = sqlite3_value_bytes(argv[argc-1]);
+  zInput = (const char *)sqlite3_value_text(argv[argc-1]);
+
+  pHash = (Fts3Hash *)sqlite3_user_data(context);
+  p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
+
+  if( !p ){
+    char *zErr2 = sqlite3_mprintf("unknown tokenizer: %s", zName);
+    sqlite3_result_error(context, zErr2, -1);
+    sqlite3_free(zErr2);
+    return;
+  }
+
+  pRet = Tcl_NewObj();
+  Tcl_IncrRefCount(pRet);
+
+  for(i=1; i<argc-1; i++){
+    azArg[i-1] = (const char *)sqlite3_value_text(argv[i]);
+  }
+
+  if( SQLITE_OK!=p->xCreate(argc-2, azArg, &pTokenizer) ){
+    zErr = "error in xCreate()";
+    goto finish;
+  }
+  pTokenizer->pModule = p;
+  if( sqlite3Fts3OpenTokenizer(pTokenizer, 0, zInput, nInput, &pCsr) ){
+    zErr = "error in xOpen()";
+    goto finish;
+  }
+
+  while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){
+    Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos));
+    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
+    zToken = &zInput[iStart];
+    nToken = iEnd-iStart;
+    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
+  }
+
+  if( SQLITE_OK!=p->xClose(pCsr) ){
+    zErr = "error in xClose()";
+    goto finish;
+  }
+  if( SQLITE_OK!=p->xDestroy(pTokenizer) ){
+    zErr = "error in xDestroy()";
+    goto finish;
+  }
+
+finish:
+  if( zErr ){
+    sqlite3_result_error(context, zErr, -1);
+  }else{
+    sqlite3_result_text(context, Tcl_GetString(pRet), -1, SQLITE_TRANSIENT);
+  }
+  Tcl_DecrRefCount(pRet);
+}
+
+static
+int registerTokenizer(
+  sqlite3 *db,
+  char *zName,
+  const sqlite3_tokenizer_module *p
+){
+  int rc;
+  sqlite3_stmt *pStmt;
+  const char zSql[] = "SELECT fts3_tokenizer(?, ?)";
+
+  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
+  sqlite3_bind_blob(pStmt, 2, &p, sizeof(p), SQLITE_STATIC);
+  sqlite3_step(pStmt);
+
+  return sqlite3_finalize(pStmt);
+}
+
+
+static
+int queryTokenizer(
+  sqlite3 *db,
+  char *zName,
+  const sqlite3_tokenizer_module **pp
+){
+  int rc;
+  sqlite3_stmt *pStmt;
+  const char zSql[] = "SELECT fts3_tokenizer(?)";
+
+  *pp = 0;
+  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB
+     && sqlite3_column_bytes(pStmt, 0)==sizeof(*pp)
+    ){
+      memcpy((void *)pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
+    }
+  }
+
+  return sqlite3_finalize(pStmt);
+}
+
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+
+/*
+** Implementation of the scalar function fts3_tokenizer_internal_test().
+** This function is used for testing only, it is not included in the
+** build unless SQLITE_TEST is defined.
+**
+** The purpose of this is to test that the fts3_tokenizer() function
+** can be used as designed by the C-code in the queryTokenizer and
+** registerTokenizer() functions above. These two functions are repeated
+** in the README.tokenizer file as an example, so it is important to
+** test them.
+**
+** To run the tests, evaluate the fts3_tokenizer_internal_test() scalar
+** function with no arguments. An assert() will fail if a problem is
+** detected. i.e.:
+**
+**     SELECT fts3_tokenizer_internal_test();
+**
+*/
+static void intTestFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int rc;
+  const sqlite3_tokenizer_module *p1;
+  const sqlite3_tokenizer_module *p2;
+  sqlite3 *db = (sqlite3 *)sqlite3_user_data(context);
+
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+
+  /* Test the query function */
+  sqlite3Fts3SimpleTokenizerModule(&p1);
+  rc = queryTokenizer(db, "simple", &p2);
+  assert( rc==SQLITE_OK );
+  assert( p1==p2 );
+  rc = queryTokenizer(db, "nosuchtokenizer", &p2);
+  assert( rc==SQLITE_ERROR );
+  assert( p2==0 );
+  assert( 0==strcmp(sqlite3_errmsg(db), "unknown tokenizer: nosuchtokenizer") );
+
+  /* Test the storage function */
+  if( fts3TokenizerEnabled(context) ){
+    rc = registerTokenizer(db, "nosuchtokenizer", p1);
+    assert( rc==SQLITE_OK );
+    rc = queryTokenizer(db, "nosuchtokenizer", &p2);
+    assert( rc==SQLITE_OK );
+    assert( p2==p1 );
+  }
+
+  sqlite3_result_text(context, "ok", -1, SQLITE_STATIC);
+}
+
+#endif
+
+/*
+** Set up SQL objects in database db used to access the contents of
+** the hash table pointed to by argument pHash. The hash table must
+** been initialized to use string keys, and to take a private copy
+** of the key when a value is inserted. i.e. by a call similar to:
+**
+**    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
+**
+** This function adds a scalar function (see header comment above
+** fts3TokenizerFunc() in this file for details) and, if ENABLE_TABLE is
+** defined at compilation time, a temporary virtual table (see header
+** comment above struct HashTableVtab) to the database schema. Both
+** provide read/write access to the contents of *pHash.
+**
+** The third argument to this function, zName, is used as the name
+** of both the scalar and, if created, the virtual table.
+*/
+SQLITE_PRIVATE int sqlite3Fts3InitHashTable(
+  sqlite3 *db,
+  Fts3Hash *pHash,
+  const char *zName
+){
+  int rc = SQLITE_OK;
+  void *p = (void *)pHash;
+  const int any = SQLITE_UTF8|SQLITE_DIRECTONLY;
+
+#ifdef SQLITE_TEST
+  char *zTest = 0;
+  char *zTest2 = 0;
+  void *pdb = (void *)db;
+  zTest = sqlite3_mprintf("%s_test", zName);
+  zTest2 = sqlite3_mprintf("%s_internal_test", zName);
+  if( !zTest || !zTest2 ){
+    rc = SQLITE_NOMEM;
+  }
+#endif
+
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zName, 1, any, p, fts3TokenizerFunc, 0, 0);
+  }
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zName, 2, any, p, fts3TokenizerFunc, 0, 0);
+  }
+#ifdef SQLITE_TEST
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zTest, -1, any, p, testFunc, 0, 0);
+  }
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0);
+  }
+#endif
+
+#ifdef SQLITE_TEST
+  sqlite3_free(zTest);
+  sqlite3_free(zTest2);
+#endif
+
+  return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_tokenizer.c **************************************/
+/************** Begin file fts3_tokenizer1.c *********************************/
+/*
+** 2006 Oct 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Implementation of the "simple" full-text-search tokenizer.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+
+/* #include "fts3_tokenizer.h" */
+
+typedef struct simple_tokenizer {
+  sqlite3_tokenizer base;
+  char delim[128];             /* flag ASCII delimiters */
+} simple_tokenizer;
+
+typedef struct simple_tokenizer_cursor {
+  sqlite3_tokenizer_cursor base;
+  const char *pInput;          /* input we are tokenizing */
+  int nBytes;                  /* size of the input */
+  int iOffset;                 /* current position in pInput */
+  int iToken;                  /* index of next token to be returned */
+  char *pToken;                /* storage for current token */
+  int nTokenAllocated;         /* space allocated to zToken buffer */
+} simple_tokenizer_cursor;
+
+
+static int simpleDelim(simple_tokenizer *t, unsigned char c){
+  return c<0x80 && t->delim[c];
+}
+static int fts3_isalnum(int x){
+  return (x>='0' && x<='9') || (x>='A' && x<='Z') || (x>='a' && x<='z');
+}
+
+/*
+** Create a new tokenizer instance.
+*/
+static int simpleCreate(
+  int argc, const char * const *argv,
+  sqlite3_tokenizer **ppTokenizer
+){
+  simple_tokenizer *t;
+
+  t = (simple_tokenizer *) sqlite3_malloc(sizeof(*t));
+  if( t==NULL ) return SQLITE_NOMEM;
+  memset(t, 0, sizeof(*t));
+
+  /* TODO(shess) Delimiters need to remain the same from run to run,
+  ** else we need to reindex.  One solution would be a meta-table to
+  ** track such information in the database, then we'd only want this
+  ** information on the initial create.
+  */
+  if( argc>1 ){
+    int i, n = (int)strlen(argv[1]);
+    for(i=0; i<n; i++){
+      unsigned char ch = argv[1][i];
+      /* We explicitly don't support UTF-8 delimiters for now. */
+      if( ch>=0x80 ){
+        sqlite3_free(t);
+        return SQLITE_ERROR;
+      }
+      t->delim[ch] = 1;
+    }
+  } else {
+    /* Mark non-alphanumeric ASCII characters as delimiters */
+    int i;
+    for(i=1; i<0x80; i++){
+      t->delim[i] = !fts3_isalnum(i) ? -1 : 0;
+    }
+  }
+
+  *ppTokenizer = &t->base;
+  return SQLITE_OK;
+}
+
+/*
+** Destroy a tokenizer
+*/
+static int simpleDestroy(sqlite3_tokenizer *pTokenizer){
+  sqlite3_free(pTokenizer);
+  return SQLITE_OK;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is pInput[0..nBytes-1].  A cursor
+** used to incrementally tokenize this string is returned in
+** *ppCursor.
+*/
+static int simpleOpen(
+  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
+  const char *pInput, int nBytes,        /* String to be tokenized */
+  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
+){
+  simple_tokenizer_cursor *c;
+
+  UNUSED_PARAMETER(pTokenizer);
+
+  c = (simple_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
+  if( c==NULL ) return SQLITE_NOMEM;
+
+  c->pInput = pInput;
+  if( pInput==0 ){
+    c->nBytes = 0;
+  }else if( nBytes<0 ){
+    c->nBytes = (int)strlen(pInput);
+  }else{
+    c->nBytes = nBytes;
+  }
+  c->iOffset = 0;                 /* start tokenizing at the beginning */
+  c->iToken = 0;
+  c->pToken = NULL;               /* no space allocated, yet. */
+  c->nTokenAllocated = 0;
+
+  *ppCursor = &c->base;
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to
+** simpleOpen() above.
+*/
+static int simpleClose(sqlite3_tokenizer_cursor *pCursor){
+  simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
+  sqlite3_free(c->pToken);
+  sqlite3_free(c);
+  return SQLITE_OK;
+}
+
+/*
+** Extract the next token from a tokenization cursor.  The cursor must
+** have been opened by a prior call to simpleOpen().
+*/
+static int simpleNext(
+  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by simpleOpen */
+  const char **ppToken,               /* OUT: *ppToken is the token text */
+  int *pnBytes,                       /* OUT: Number of bytes in token */
+  int *piStartOffset,                 /* OUT: Starting offset of token */
+  int *piEndOffset,                   /* OUT: Ending offset of token */
+  int *piPosition                     /* OUT: Position integer of token */
+){
+  simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
+  simple_tokenizer *t = (simple_tokenizer *) pCursor->pTokenizer;
+  unsigned char *p = (unsigned char *)c->pInput;
+
+  while( c->iOffset<c->nBytes ){
+    int iStartOffset;
+
+    /* Scan past delimiter characters */
+    while( c->iOffset<c->nBytes && simpleDelim(t, p[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    /* Count non-delimiter characters. */
+    iStartOffset = c->iOffset;
+    while( c->iOffset<c->nBytes && !simpleDelim(t, p[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    if( c->iOffset>iStartOffset ){
+      int i, n = c->iOffset-iStartOffset;
+      if( n>c->nTokenAllocated ){
+        char *pNew;
+        c->nTokenAllocated = n+20;
+        pNew = sqlite3_realloc64(c->pToken, c->nTokenAllocated);
+        if( !pNew ) return SQLITE_NOMEM;
+        c->pToken = pNew;
+      }
+      for(i=0; i<n; i++){
+        /* TODO(shess) This needs expansion to handle UTF-8
+        ** case-insensitivity.
+        */
+        unsigned char ch = p[iStartOffset+i];
+        c->pToken[i] = (char)((ch>='A' && ch<='Z') ? ch-'A'+'a' : ch);
+      }
+      *ppToken = c->pToken;
+      *pnBytes = n;
+      *piStartOffset = iStartOffset;
+      *piEndOffset = c->iOffset;
+      *piPosition = c->iToken++;
+
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_DONE;
+}
+
+/*
+** The set of routines that implement the simple tokenizer
+*/
+static const sqlite3_tokenizer_module simpleTokenizerModule = {
+  0,
+  simpleCreate,
+  simpleDestroy,
+  simpleOpen,
+  simpleClose,
+  simpleNext,
+  0,
+};
+
+/*
+** Allocate a new simple tokenizer.  Return a pointer to the new
+** tokenizer in *ppModule
+*/
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(
+  sqlite3_tokenizer_module const**ppModule
+){
+  *ppModule = &simpleTokenizerModule;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_tokenizer1.c *************************************/
+/************** Begin file fts3_tokenize_vtab.c ******************************/
+/*
+** 2013 Apr 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code for the "fts3tokenize" virtual table module.
+** An fts3tokenize virtual table is created as follows:
+**
+**   CREATE VIRTUAL TABLE <tbl> USING fts3tokenize(
+**       <tokenizer-name>, <arg-1>, ...
+**   );
+**
+** The table created has the following schema:
+**
+**   CREATE TABLE <tbl>(input, token, start, end, position)
+**
+** When queried, the query must include a WHERE clause of type:
+**
+**   input = <string>
+**
+** The virtual table module tokenizes this <string>, using the FTS3
+** tokenizer specified by the arguments to the CREATE VIRTUAL TABLE
+** statement and returns one row for each token in the result. With
+** fields set as follows:
+**
+**   input:   Always set to a copy of <string>
+**   token:   A token from the input.
+**   start:   Byte offset of the token within the input <string>.
+**   end:     Byte offset of the byte immediately following the end of the
+**            token within the input string.
+**   pos:     Token offset of token within input.
+**
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+typedef struct Fts3tokTable Fts3tokTable;
+typedef struct Fts3tokCursor Fts3tokCursor;
+
+/*
+** Virtual table structure.
+*/
+struct Fts3tokTable {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  const sqlite3_tokenizer_module *pMod;
+  sqlite3_tokenizer *pTok;
+};
+
+/*
+** Virtual table cursor structure.
+*/
+struct Fts3tokCursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  char *zInput;                   /* Input string */
+  sqlite3_tokenizer_cursor *pCsr; /* Cursor to iterate through zInput */
+  int iRowid;                     /* Current 'rowid' value */
+  const char *zToken;             /* Current 'token' value */
+  int nToken;                     /* Size of zToken in bytes */
+  int iStart;                     /* Current 'start' value */
+  int iEnd;                       /* Current 'end' value */
+  int iPos;                       /* Current 'pos' value */
+};
+
+/*
+** Query FTS for the tokenizer implementation named zName.
+*/
+static int fts3tokQueryTokenizer(
+  Fts3Hash *pHash,
+  const char *zName,
+  const sqlite3_tokenizer_module **pp,
+  char **pzErr
+){
+  sqlite3_tokenizer_module *p;
+  int nName = (int)strlen(zName);
+
+  p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
+  if( !p ){
+    sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer: %s", zName);
+    return SQLITE_ERROR;
+  }
+
+  *pp = p;
+  return SQLITE_OK;
+}
+
+/*
+** The second argument, argv[], is an array of pointers to nul-terminated
+** strings. This function makes a copy of the array and strings into a
+** single block of memory. It then dequotes any of the strings that appear
+** to be quoted.
+**
+** If successful, output parameter *pazDequote is set to point at the
+** array of dequoted strings and SQLITE_OK is returned. The caller is
+** responsible for eventually calling sqlite3_free() to free the array
+** in this case. Or, if an error occurs, an SQLite error code is returned.
+** The final value of *pazDequote is undefined in this case.
+*/
+static int fts3tokDequoteArray(
+  int argc,                       /* Number of elements in argv[] */
+  const char * const *argv,       /* Input array */
+  char ***pazDequote              /* Output array */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  if( argc==0 ){
+    *pazDequote = 0;
+  }else{
+    int i;
+    int nByte = 0;
+    char **azDequote;
+
+    for(i=0; i<argc; i++){
+      nByte += (int)(strlen(argv[i]) + 1);
+    }
+
+    *pazDequote = azDequote = sqlite3_malloc64(sizeof(char *)*argc + nByte);
+    if( azDequote==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      char *pSpace = (char *)&azDequote[argc];
+      for(i=0; i<argc; i++){
+        int n = (int)strlen(argv[i]);
+        azDequote[i] = pSpace;
+        memcpy(pSpace, argv[i], n+1);
+        sqlite3Fts3Dequote(pSpace);
+        pSpace += (n+1);
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Schema of the tokenizer table.
+*/
+#define FTS3_TOK_SCHEMA "CREATE TABLE x(input, token, start, end, position)"
+
+/*
+** This function does all the work for both the xConnect and xCreate methods.
+** These tables have no persistent representation of their own, so xConnect
+** and xCreate are identical operations.
+**
+**   argv[0]: module name
+**   argv[1]: database name
+**   argv[2]: table name
+**   argv[3]: first argument (tokenizer name)
+*/
+static int fts3tokConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pHash,                    /* Hash table of tokenizers */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  Fts3tokTable *pTab = 0;
+  const sqlite3_tokenizer_module *pMod = 0;
+  sqlite3_tokenizer *pTok = 0;
+  int rc;
+  char **azDequote = 0;
+  int nDequote;
+
+  rc = sqlite3_declare_vtab(db, FTS3_TOK_SCHEMA);
+  if( rc!=SQLITE_OK ) return rc;
+
+  nDequote = argc-3;
+  rc = fts3tokDequoteArray(nDequote, &argv[3], &azDequote);
+
+  if( rc==SQLITE_OK ){
+    const char *zModule;
+    if( nDequote<1 ){
+      zModule = "simple";
+    }else{
+      zModule = azDequote[0];
+    }
+    rc = fts3tokQueryTokenizer((Fts3Hash*)pHash, zModule, &pMod, pzErr);
+  }
+
+  assert( (rc==SQLITE_OK)==(pMod!=0) );
+  if( rc==SQLITE_OK ){
+    const char * const *azArg = 0;
+    if( nDequote>1 ) azArg = (const char * const *)&azDequote[1];
+    rc = pMod->xCreate((nDequote>1 ? nDequote-1 : 0), azArg, &pTok);
+  }
+
+  if( rc==SQLITE_OK ){
+    pTab = (Fts3tokTable *)sqlite3_malloc(sizeof(Fts3tokTable));
+    if( pTab==0 ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    memset(pTab, 0, sizeof(Fts3tokTable));
+    pTab->pMod = pMod;
+    pTab->pTok = pTok;
+    *ppVtab = &pTab->base;
+  }else{
+    if( pTok ){
+      pMod->xDestroy(pTok);
+    }
+  }
+
+  sqlite3_free(azDequote);
+  return rc;
+}
+
+/*
+** This function does the work for both the xDisconnect and xDestroy methods.
+** These tables have no persistent representation of their own, so xDisconnect
+** and xDestroy are identical operations.
+*/
+static int fts3tokDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3tokTable *pTab = (Fts3tokTable *)pVtab;
+
+  pTab->pMod->xDestroy(pTab->pTok);
+  sqlite3_free(pTab);
+  return SQLITE_OK;
+}
+
+/*
+** xBestIndex - Analyze a WHERE and ORDER BY clause.
+*/
+static int fts3tokBestIndexMethod(
+  sqlite3_vtab *pVTab,
+  sqlite3_index_info *pInfo
+){
+  int i;
+  UNUSED_PARAMETER(pVTab);
+
+  for(i=0; i<pInfo->nConstraint; i++){
+    if( pInfo->aConstraint[i].usable
+     && pInfo->aConstraint[i].iColumn==0
+     && pInfo->aConstraint[i].op==SQLITE_INDEX_CONSTRAINT_EQ
+    ){
+      pInfo->idxNum = 1;
+      pInfo->aConstraintUsage[i].argvIndex = 1;
+      pInfo->aConstraintUsage[i].omit = 1;
+      pInfo->estimatedCost = 1;
+      return SQLITE_OK;
+    }
+  }
+
+  pInfo->idxNum = 0;
+  assert( pInfo->estimatedCost>1000000.0 );
+
+  return SQLITE_OK;
+}
+
+/*
+** xOpen - Open a cursor.
+*/
+static int fts3tokOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  Fts3tokCursor *pCsr;
+  UNUSED_PARAMETER(pVTab);
+
+  pCsr = (Fts3tokCursor *)sqlite3_malloc(sizeof(Fts3tokCursor));
+  if( pCsr==0 ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(Fts3tokCursor));
+
+  *ppCsr = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** Reset the tokenizer cursor passed as the only argument. As if it had
+** just been returned by fts3tokOpenMethod().
+*/
+static void fts3tokResetCursor(Fts3tokCursor *pCsr){
+  if( pCsr->pCsr ){
+    Fts3tokTable *pTab = (Fts3tokTable *)(pCsr->base.pVtab);
+    pTab->pMod->xClose(pCsr->pCsr);
+    pCsr->pCsr = 0;
+  }
+  sqlite3_free(pCsr->zInput);
+  pCsr->zInput = 0;
+  pCsr->zToken = 0;
+  pCsr->nToken = 0;
+  pCsr->iStart = 0;
+  pCsr->iEnd = 0;
+  pCsr->iPos = 0;
+  pCsr->iRowid = 0;
+}
+
+/*
+** xClose - Close a cursor.
+*/
+static int fts3tokCloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+
+  fts3tokResetCursor(pCsr);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** xNext - Advance the cursor to the next row, if any.
+*/
+static int fts3tokNextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+  Fts3tokTable *pTab = (Fts3tokTable *)(pCursor->pVtab);
+  int rc;                         /* Return code */
+
+  pCsr->iRowid++;
+  rc = pTab->pMod->xNext(pCsr->pCsr,
+      &pCsr->zToken, &pCsr->nToken,
+      &pCsr->iStart, &pCsr->iEnd, &pCsr->iPos
+  );
+
+  if( rc!=SQLITE_OK ){
+    fts3tokResetCursor(pCsr);
+    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  }
+
+  return rc;
+}
+
+/*
+** xFilter - Initialize a cursor to point at the start of its data.
+*/
+static int fts3tokFilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  int rc = SQLITE_ERROR;
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+  Fts3tokTable *pTab = (Fts3tokTable *)(pCursor->pVtab);
+  UNUSED_PARAMETER(idxStr);
+  UNUSED_PARAMETER(nVal);
+
+  fts3tokResetCursor(pCsr);
+  if( idxNum==1 ){
+    const char *zByte = (const char *)sqlite3_value_text(apVal[0]);
+    int nByte = sqlite3_value_bytes(apVal[0]);
+    pCsr->zInput = sqlite3_malloc64(nByte+1);
+    if( pCsr->zInput==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      if( nByte>0 ) memcpy(pCsr->zInput, zByte, nByte);
+      pCsr->zInput[nByte] = 0;
+      rc = pTab->pMod->xOpen(pTab->pTok, pCsr->zInput, nByte, &pCsr->pCsr);
+      if( rc==SQLITE_OK ){
+        pCsr->pCsr->pTokenizer = pTab->pTok;
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ) return rc;
+  return fts3tokNextMethod(pCursor);
+}
+
+/*
+** xEof - Return true if the cursor is at EOF, or false otherwise.
+*/
+static int fts3tokEofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+  return (pCsr->zToken==0);
+}
+
+/*
+** xColumn - Return a column value.
+*/
+static int fts3tokColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+
+  /* CREATE TABLE x(input, token, start, end, position) */
+  switch( iCol ){
+    case 0:
+      sqlite3_result_text(pCtx, pCsr->zInput, -1, SQLITE_TRANSIENT);
+      break;
+    case 1:
+      sqlite3_result_text(pCtx, pCsr->zToken, pCsr->nToken, SQLITE_TRANSIENT);
+      break;
+    case 2:
+      sqlite3_result_int(pCtx, pCsr->iStart);
+      break;
+    case 3:
+      sqlite3_result_int(pCtx, pCsr->iEnd);
+      break;
+    default:
+      assert( iCol==4 );
+      sqlite3_result_int(pCtx, pCsr->iPos);
+      break;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** xRowid - Return the current rowid for the cursor.
+*/
+static int fts3tokRowidMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite_int64 *pRowid            /* OUT: Rowid value */
+){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+  *pRowid = (sqlite3_int64)pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Register the fts3tok module with database connection db. Return SQLITE_OK
+** if successful or an error code if sqlite3_create_module() fails.
+*/
+SQLITE_PRIVATE int sqlite3Fts3InitTok(sqlite3 *db, Fts3Hash *pHash, void(*xDestroy)(void*)){
+  static const sqlite3_module fts3tok_module = {
+     0,                           /* iVersion      */
+     fts3tokConnectMethod,        /* xCreate       */
+     fts3tokConnectMethod,        /* xConnect      */
+     fts3tokBestIndexMethod,      /* xBestIndex    */
+     fts3tokDisconnectMethod,     /* xDisconnect   */
+     fts3tokDisconnectMethod,     /* xDestroy      */
+     fts3tokOpenMethod,           /* xOpen         */
+     fts3tokCloseMethod,          /* xClose        */
+     fts3tokFilterMethod,         /* xFilter       */
+     fts3tokNextMethod,           /* xNext         */
+     fts3tokEofMethod,            /* xEof          */
+     fts3tokColumnMethod,         /* xColumn       */
+     fts3tokRowidMethod,          /* xRowid        */
+     0,                           /* xUpdate       */
+     0,                           /* xBegin        */
+     0,                           /* xSync         */
+     0,                           /* xCommit       */
+     0,                           /* xRollback     */
+     0,                           /* xFindFunction */
+     0,                           /* xRename       */
+     0,                           /* xSavepoint    */
+     0,                           /* xRelease      */
+     0,                           /* xRollbackTo   */
+     0,                           /* xShadowName   */
+     0                            /* xIntegrity    */
+  };
+  int rc;                         /* Return code */
+
+  rc = sqlite3_create_module_v2(
+      db, "fts3tokenize", &fts3tok_module, (void*)pHash, xDestroy
+  );
+  return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_tokenize_vtab.c **********************************/
+/************** Begin file fts3_write.c **************************************/
+/*
+** 2009 Oct 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file is part of the SQLite FTS3 extension module. Specifically,
+** this file contains code to insert, update and delete rows from FTS3
+** tables. It also contains code to merge FTS3 b-tree segments. Some
+** of the sub-routines used to merge segments are also used by the query
+** code in fts3.c.
+*/
+
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+
+#define FTS_MAX_APPENDABLE_HEIGHT 16
+
+/*
+** When full-text index nodes are loaded from disk, the buffer that they
+** are loaded into has the following number of bytes of padding at the end
+** of it. i.e. if a full-text index node is 900 bytes in size, then a buffer
+** of 920 bytes is allocated for it.
+**
+** This means that if we have a pointer into a buffer containing node data,
+** it is always safe to read up to two varints from it without risking an
+** overread, even if the node data is corrupted.
+*/
+#define FTS3_NODE_PADDING (FTS3_VARINT_MAX*2)
+
+/*
+** Under certain circumstances, b-tree nodes (doclists) can be loaded into
+** memory incrementally instead of all at once. This can be a big performance
+** win (reduced IO and CPU) if SQLite stops calling the virtual table xNext()
+** method before retrieving all query results (as may happen, for example,
+** if a query has a LIMIT clause).
+**
+** Incremental loading is used for b-tree nodes FTS3_NODE_CHUNK_THRESHOLD
+** bytes and larger. Nodes are loaded in chunks of FTS3_NODE_CHUNKSIZE bytes.
+** The code is written so that the hard lower-limit for each of these values
+** is 1. Clearly such small values would be inefficient, but can be useful
+** for testing purposes.
+**
+** If this module is built with SQLITE_TEST defined, these constants may
+** be overridden at runtime for testing purposes. File fts3_test.c contains
+** a Tcl interface to read and write the values.
+*/
+#ifdef SQLITE_TEST
+int test_fts3_node_chunksize = (4*1024);
+int test_fts3_node_chunk_threshold = (4*1024)*4;
+# define FTS3_NODE_CHUNKSIZE       test_fts3_node_chunksize
+# define FTS3_NODE_CHUNK_THRESHOLD test_fts3_node_chunk_threshold
+#else
+# define FTS3_NODE_CHUNKSIZE (4*1024)
+# define FTS3_NODE_CHUNK_THRESHOLD (FTS3_NODE_CHUNKSIZE*4)
+#endif
+
+/*
+** The values that may be meaningfully bound to the :1 parameter in
+** statements SQL_REPLACE_STAT and SQL_SELECT_STAT.
+*/
+#define FTS_STAT_DOCTOTAL      0
+#define FTS_STAT_INCRMERGEHINT 1
+#define FTS_STAT_AUTOINCRMERGE 2
+
+/*
+** If FTS_LOG_MERGES is defined, call sqlite3_log() to report each automatic
+** and incremental merge operation that takes place. This is used for
+** debugging FTS only, it should not usually be turned on in production
+** systems.
+*/
+#ifdef FTS3_LOG_MERGES
+static void fts3LogMerge(int nMerge, sqlite3_int64 iAbsLevel){
+  sqlite3_log(SQLITE_OK, "%d-way merge from level %d", nMerge, (int)iAbsLevel);
+}
+#else
+#define fts3LogMerge(x, y)
+#endif
+
+
+typedef struct PendingList PendingList;
+typedef struct SegmentNode SegmentNode;
+typedef struct SegmentWriter SegmentWriter;
+
+/*
+** An instance of the following data structure is used to build doclists
+** incrementally. See function fts3PendingListAppend() for details.
+*/
+struct PendingList {
+  int nData;
+  char *aData;
+  int nSpace;
+  sqlite3_int64 iLastDocid;
+  sqlite3_int64 iLastCol;
+  sqlite3_int64 iLastPos;
+};
+
+
+/*
+** Each cursor has a (possibly empty) linked list of the following objects.
+*/
+struct Fts3DeferredToken {
+  Fts3PhraseToken *pToken;        /* Pointer to corresponding expr token */
+  int iCol;                       /* Column token must occur in */
+  Fts3DeferredToken *pNext;       /* Next in list of deferred tokens */
+  PendingList *pList;             /* Doclist is assembled here */
+};
+
+/*
+** An instance of this structure is used to iterate through the terms on
+** a contiguous set of segment b-tree leaf nodes. Although the details of
+** this structure are only manipulated by code in this file, opaque handles
+** of type Fts3SegReader* are also used by code in fts3.c to iterate through
+** terms when querying the full-text index. See functions:
+**
+**   sqlite3Fts3SegReaderNew()
+**   sqlite3Fts3SegReaderFree()
+**   sqlite3Fts3SegReaderIterate()
+**
+** Methods used to manipulate Fts3SegReader structures:
+**
+**   fts3SegReaderNext()
+**   fts3SegReaderFirstDocid()
+**   fts3SegReaderNextDocid()
+*/
+struct Fts3SegReader {
+  int iIdx;                       /* Index within level, or 0x7FFFFFFF for PT */
+  u8 bLookup;                     /* True for a lookup only */
+  u8 rootOnly;                    /* True for a root-only reader */
+
+  sqlite3_int64 iStartBlock;      /* Rowid of first leaf block to traverse */
+  sqlite3_int64 iLeafEndBlock;    /* Rowid of final leaf block to traverse */
+  sqlite3_int64 iEndBlock;        /* Rowid of final block in segment (or 0) */
+  sqlite3_int64 iCurrentBlock;    /* Current leaf block (or 0) */
+
+  char *aNode;                    /* Pointer to node data (or NULL) */
+  int nNode;                      /* Size of buffer at aNode (or 0) */
+  int nPopulate;                  /* If >0, bytes of buffer aNode[] loaded */
+  sqlite3_blob *pBlob;            /* If not NULL, blob handle to read node */
+
+  Fts3HashElem **ppNextElem;
+
+  /* Variables set by fts3SegReaderNext(). These may be read directly
+  ** by the caller. They are valid from the time SegmentReaderNew() returns
+  ** until SegmentReaderNext() returns something other than SQLITE_OK
+  ** (i.e. SQLITE_DONE).
+  */
+  int nTerm;                      /* Number of bytes in current term */
+  char *zTerm;                    /* Pointer to current term */
+  int nTermAlloc;                 /* Allocated size of zTerm buffer */
+  char *aDoclist;                 /* Pointer to doclist of current entry */
+  int nDoclist;                   /* Size of doclist in current entry */
+
+  /* The following variables are used by fts3SegReaderNextDocid() to iterate
+  ** through the current doclist (aDoclist/nDoclist).
+  */
+  char *pOffsetList;
+  int nOffsetList;                /* For descending pending seg-readers only */
+  sqlite3_int64 iDocid;
+};
+
+#define fts3SegReaderIsPending(p) ((p)->ppNextElem!=0)
+#define fts3SegReaderIsRootOnly(p) ((p)->rootOnly!=0)
+
+/*
+** An instance of this structure is used to create a segment b-tree in the
+** database. The internal details of this type are only accessed by the
+** following functions:
+**
+**   fts3SegWriterAdd()
+**   fts3SegWriterFlush()
+**   fts3SegWriterFree()
+*/
+struct SegmentWriter {
+  SegmentNode *pTree;             /* Pointer to interior tree structure */
+  sqlite3_int64 iFirst;           /* First slot in %_segments written */
+  sqlite3_int64 iFree;            /* Next free slot in %_segments */
+  char *zTerm;                    /* Pointer to previous term buffer */
+  int nTerm;                      /* Number of bytes in zTerm */
+  int nMalloc;                    /* Size of malloc'd buffer at zMalloc */
+  char *zMalloc;                  /* Malloc'd space (possibly) used for zTerm */
+  int nSize;                      /* Size of allocation at aData */
+  int nData;                      /* Bytes of data in aData */
+  char *aData;                    /* Pointer to block from malloc() */
+  i64 nLeafData;                  /* Number of bytes of leaf data written */
+};
+
+/*
+** Type SegmentNode is used by the following three functions to create
+** the interior part of the segment b+-tree structures (everything except
+** the leaf nodes). These functions and type are only ever used by code
+** within the fts3SegWriterXXX() family of functions described above.
+**
+**   fts3NodeAddTerm()
+**   fts3NodeWrite()
+**   fts3NodeFree()
+**
+** When a b+tree is written to the database (either as a result of a merge
+** or the pending-terms table being flushed), leaves are written into the
+** database file as soon as they are completely populated. The interior of
+** the tree is assembled in memory and written out only once all leaves have
+** been populated and stored. This is Ok, as the b+-tree fanout is usually
+** very large, meaning that the interior of the tree consumes relatively
+** little memory.
+*/
+struct SegmentNode {
+  SegmentNode *pParent;           /* Parent node (or NULL for root node) */
+  SegmentNode *pRight;            /* Pointer to right-sibling */
+  SegmentNode *pLeftmost;         /* Pointer to left-most node of this depth */
+  int nEntry;                     /* Number of terms written to node so far */
+  char *zTerm;                    /* Pointer to previous term buffer */
+  int nTerm;                      /* Number of bytes in zTerm */
+  int nMalloc;                    /* Size of malloc'd buffer at zMalloc */
+  char *zMalloc;                  /* Malloc'd space (possibly) used for zTerm */
+  int nData;                      /* Bytes of valid data so far */
+  char *aData;                    /* Node data */
+};
+
+/*
+** Valid values for the second argument to fts3SqlStmt().
+*/
+#define SQL_DELETE_CONTENT             0
+#define SQL_IS_EMPTY                   1
+#define SQL_DELETE_ALL_CONTENT         2
+#define SQL_DELETE_ALL_SEGMENTS        3
+#define SQL_DELETE_ALL_SEGDIR          4
+#define SQL_DELETE_ALL_DOCSIZE         5
+#define SQL_DELETE_ALL_STAT            6
+#define SQL_SELECT_CONTENT_BY_ROWID    7
+#define SQL_NEXT_SEGMENT_INDEX         8
+#define SQL_INSERT_SEGMENTS            9
+#define SQL_NEXT_SEGMENTS_ID          10
+#define SQL_INSERT_SEGDIR             11
+#define SQL_SELECT_LEVEL              12
+#define SQL_SELECT_LEVEL_RANGE        13
+#define SQL_SELECT_LEVEL_COUNT        14
+#define SQL_SELECT_SEGDIR_MAX_LEVEL   15
+#define SQL_DELETE_SEGDIR_LEVEL       16
+#define SQL_DELETE_SEGMENTS_RANGE     17
+#define SQL_CONTENT_INSERT            18
+#define SQL_DELETE_DOCSIZE            19
+#define SQL_REPLACE_DOCSIZE           20
+#define SQL_SELECT_DOCSIZE            21
+#define SQL_SELECT_STAT               22
+#define SQL_REPLACE_STAT              23
+
+#define SQL_SELECT_ALL_PREFIX_LEVEL   24
+#define SQL_DELETE_ALL_TERMS_SEGDIR   25
+#define SQL_DELETE_SEGDIR_RANGE       26
+#define SQL_SELECT_ALL_LANGID         27
+#define SQL_FIND_MERGE_LEVEL          28
+#define SQL_MAX_LEAF_NODE_ESTIMATE    29
+#define SQL_DELETE_SEGDIR_ENTRY       30
+#define SQL_SHIFT_SEGDIR_ENTRY        31
+#define SQL_SELECT_SEGDIR             32
+#define SQL_CHOMP_SEGDIR              33
+#define SQL_SEGMENT_IS_APPENDABLE     34
+#define SQL_SELECT_INDEXES            35
+#define SQL_SELECT_MXLEVEL            36
+
+#define SQL_SELECT_LEVEL_RANGE2       37
+#define SQL_UPDATE_LEVEL_IDX          38
+#define SQL_UPDATE_LEVEL              39
+
+/*
+** This function is used to obtain an SQLite prepared statement handle
+** for the statement identified by the second argument. If successful,
+** *pp is set to the requested statement handle and SQLITE_OK returned.
+** Otherwise, an SQLite error code is returned and *pp is set to 0.
+**
+** If argument apVal is not NULL, then it must point to an array with
+** at least as many entries as the requested statement has bound
+** parameters. The values are bound to the statements parameters before
+** returning.
+*/
+static int fts3SqlStmt(
+  Fts3Table *p,                   /* Virtual table handle */
+  int eStmt,                      /* One of the SQL_XXX constants above */
+  sqlite3_stmt **pp,              /* OUT: Statement handle */
+  sqlite3_value **apVal           /* Values to bind to statement */
+){
+  const char *azSql[] = {
+/* 0  */  "DELETE FROM %Q.'%q_content' WHERE rowid = ?",
+/* 1  */  "SELECT NOT EXISTS(SELECT docid FROM %Q.'%q_content' WHERE rowid!=?)",
+/* 2  */  "DELETE FROM %Q.'%q_content'",
+/* 3  */  "DELETE FROM %Q.'%q_segments'",
+/* 4  */  "DELETE FROM %Q.'%q_segdir'",
+/* 5  */  "DELETE FROM %Q.'%q_docsize'",
+/* 6  */  "DELETE FROM %Q.'%q_stat'",
+/* 7  */  "SELECT %s WHERE rowid=?",
+/* 8  */  "SELECT (SELECT max(idx) FROM %Q.'%q_segdir' WHERE level = ?) + 1",
+/* 9  */  "REPLACE INTO %Q.'%q_segments'(blockid, block) VALUES(?, ?)",
+/* 10 */  "SELECT coalesce((SELECT max(blockid) FROM %Q.'%q_segments') + 1, 1)",
+/* 11 */  "REPLACE INTO %Q.'%q_segdir' VALUES(?,?,?,?,?,?)",
+
+          /* Return segments in order from oldest to newest.*/
+/* 12 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level = ? ORDER BY idx ASC",
+/* 13 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?"
+            "ORDER BY level DESC, idx ASC",
+
+/* 14 */  "SELECT count(*) FROM %Q.'%q_segdir' WHERE level = ?",
+/* 15 */  "SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",
+
+/* 16 */  "DELETE FROM %Q.'%q_segdir' WHERE level = ?",
+/* 17 */  "DELETE FROM %Q.'%q_segments' WHERE blockid BETWEEN ? AND ?",
+/* 18 */  "INSERT INTO %Q.'%q_content' VALUES(%s)",
+/* 19 */  "DELETE FROM %Q.'%q_docsize' WHERE docid = ?",
+/* 20 */  "REPLACE INTO %Q.'%q_docsize' VALUES(?,?)",
+/* 21 */  "SELECT size FROM %Q.'%q_docsize' WHERE docid=?",
+/* 22 */  "SELECT value FROM %Q.'%q_stat' WHERE id=?",
+/* 23 */  "REPLACE INTO %Q.'%q_stat' VALUES(?,?)",
+/* 24 */  "",
+/* 25 */  "",
+
+/* 26 */ "DELETE FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",
+/* 27 */ "SELECT ? UNION SELECT level / (1024 * ?) FROM %Q.'%q_segdir'",
+
+/* This statement is used to determine which level to read the input from
+** when performing an incremental merge. It returns the absolute level number
+** of the oldest level in the db that contains at least ? segments. Or,
+** if no level in the FTS index contains more than ? segments, the statement
+** returns zero rows.  */
+/* 28 */ "SELECT level, count(*) AS cnt FROM %Q.'%q_segdir' "
+         "  GROUP BY level HAVING cnt>=?"
+         "  ORDER BY (level %% 1024) ASC, 2 DESC LIMIT 1",
+
+/* Estimate the upper limit on the number of leaf nodes in a new segment
+** created by merging the oldest :2 segments from absolute level :1. See
+** function sqlite3Fts3Incrmerge() for details.  */
+/* 29 */ "SELECT 2 * total(1 + leaves_end_block - start_block) "
+         "  FROM (SELECT * FROM %Q.'%q_segdir' "
+         "        WHERE level = ? ORDER BY idx ASC LIMIT ?"
+         "  )",
+
+/* SQL_DELETE_SEGDIR_ENTRY
+**   Delete the %_segdir entry on absolute level :1 with index :2.  */
+/* 30 */ "DELETE FROM %Q.'%q_segdir' WHERE level = ? AND idx = ?",
+
+/* SQL_SHIFT_SEGDIR_ENTRY
+**   Modify the idx value for the segment with idx=:3 on absolute level :2
+**   to :1.  */
+/* 31 */ "UPDATE %Q.'%q_segdir' SET idx = ? WHERE level=? AND idx=?",
+
+/* SQL_SELECT_SEGDIR
+**   Read a single entry from the %_segdir table. The entry from absolute
+**   level :1 with index value :2.  */
+/* 32 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level = ? AND idx = ?",
+
+/* SQL_CHOMP_SEGDIR
+**   Update the start_block (:1) and root (:2) fields of the %_segdir
+**   entry located on absolute level :3 with index :4.  */
+/* 33 */  "UPDATE %Q.'%q_segdir' SET start_block = ?, root = ?"
+            "WHERE level = ? AND idx = ?",
+
+/* SQL_SEGMENT_IS_APPENDABLE
+**   Return a single row if the segment with end_block=? is appendable. Or
+**   no rows otherwise.  */
+/* 34 */  "SELECT 1 FROM %Q.'%q_segments' WHERE blockid=? AND block IS NULL",
+
+/* SQL_SELECT_INDEXES
+**   Return the list of valid segment indexes for absolute level ?  */
+/* 35 */  "SELECT idx FROM %Q.'%q_segdir' WHERE level=? ORDER BY 1 ASC",
+
+/* SQL_SELECT_MXLEVEL
+**   Return the largest relative level in the FTS index or indexes.  */
+/* 36 */  "SELECT max( level %% 1024 ) FROM %Q.'%q_segdir'",
+
+          /* Return segments in order from oldest to newest.*/
+/* 37 */  "SELECT level, idx, end_block "
+            "FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ? "
+            "ORDER BY level DESC, idx ASC",
+
+          /* Update statements used while promoting segments */
+/* 38 */  "UPDATE OR FAIL %Q.'%q_segdir' SET level=-1,idx=? "
+            "WHERE level=? AND idx=?",
+/* 39 */  "UPDATE OR FAIL %Q.'%q_segdir' SET level=? WHERE level=-1"
+
+  };
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pStmt;
+
+  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
+  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
+
+  pStmt = p->aStmt[eStmt];
+  if( !pStmt ){
+    int f = SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB;
+    char *zSql;
+    if( eStmt==SQL_CONTENT_INSERT ){
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName, p->zWriteExprlist);
+    }else if( eStmt==SQL_SELECT_CONTENT_BY_ROWID ){
+      f &= ~SQLITE_PREPARE_NO_VTAB;
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zReadExprlist);
+    }else{
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName);
+    }
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v3(p->db, zSql, -1, f, &pStmt, NULL);
+      sqlite3_free(zSql);
+      assert( rc==SQLITE_OK || pStmt==0 );
+      p->aStmt[eStmt] = pStmt;
+    }
+  }
+  if( apVal ){
+    int i;
+    int nParam = sqlite3_bind_parameter_count(pStmt);
+    for(i=0; rc==SQLITE_OK && i<nParam; i++){
+      rc = sqlite3_bind_value(pStmt, i+1, apVal[i]);
+    }
+  }
+  *pp = pStmt;
+  return rc;
+}
+
+
+static int fts3SelectDocsize(
+  Fts3Table *pTab,                /* FTS3 table handle */
+  sqlite3_int64 iDocid,           /* Docid to bind for SQL_SELECT_DOCSIZE */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  sqlite3_stmt *pStmt = 0;        /* Statement requested from fts3SqlStmt() */
+  int rc;                         /* Return code */
+
+  rc = fts3SqlStmt(pTab, SQL_SELECT_DOCSIZE, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iDocid);
+    rc = sqlite3_step(pStmt);
+    if( rc!=SQLITE_ROW || sqlite3_column_type(pStmt, 0)!=SQLITE_BLOB ){
+      rc = sqlite3_reset(pStmt);
+      if( rc==SQLITE_OK ) rc = FTS_CORRUPT_VTAB;
+      pStmt = 0;
+    }else{
+      rc = SQLITE_OK;
+    }
+  }
+
+  *ppStmt = pStmt;
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3SelectDoctotal(
+  Fts3Table *pTab,                /* Fts3 table handle */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  sqlite3_stmt *pStmt = 0;
+  int rc;
+  rc = fts3SqlStmt(pTab, SQL_SELECT_STAT, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
+    if( sqlite3_step(pStmt)!=SQLITE_ROW
+     || sqlite3_column_type(pStmt, 0)!=SQLITE_BLOB
+    ){
+      rc = sqlite3_reset(pStmt);
+      if( rc==SQLITE_OK ) rc = FTS_CORRUPT_VTAB;
+      pStmt = 0;
+    }
+  }
+  *ppStmt = pStmt;
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3SelectDocsize(
+  Fts3Table *pTab,                /* Fts3 table handle */
+  sqlite3_int64 iDocid,           /* Docid to read size data for */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  return fts3SelectDocsize(pTab, iDocid, ppStmt);
+}
+
+/*
+** Similar to fts3SqlStmt(). Except, after binding the parameters in
+** array apVal[] to the SQL statement identified by eStmt, the statement
+** is executed.
+**
+** Returns SQLITE_OK if the statement is successfully executed, or an
+** SQLite error code otherwise.
+*/
+static void fts3SqlExec(
+  int *pRC,                /* Result code */
+  Fts3Table *p,            /* The FTS3 table */
+  int eStmt,               /* Index of statement to evaluate */
+  sqlite3_value **apVal    /* Parameters to bind */
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+  if( *pRC ) return;
+  rc = fts3SqlStmt(p, eStmt, &pStmt, apVal);
+  if( rc==SQLITE_OK ){
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+  }
+  *pRC = rc;
+}
+
+
+/*
+** This function ensures that the caller has obtained an exclusive
+** shared-cache table-lock on the %_segdir table. This is required before
+** writing data to the fts3 table. If this lock is not acquired first, then
+** the caller may end up attempting to take this lock as part of committing
+** a transaction, causing SQLite to return SQLITE_LOCKED or
+** LOCKED_SHAREDCACHEto a COMMIT command.
+**
+** It is best to avoid this because if FTS3 returns any error when
+** committing a transaction, the whole transaction will be rolled back.
+** And this is not what users expect when they get SQLITE_LOCKED_SHAREDCACHE.
+** It can still happen if the user locks the underlying tables directly
+** instead of accessing them via FTS.
+*/
+static int fts3Writelock(Fts3Table *p){
+  int rc = SQLITE_OK;
+
+  if( p->nPendingData==0 ){
+    sqlite3_stmt *pStmt;
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_LEVEL, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_null(pStmt, 1);
+      sqlite3_step(pStmt);
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** FTS maintains a separate indexes for each language-id (a 32-bit integer).
+** Within each language id, a separate index is maintained to store the
+** document terms, and each configured prefix size (configured the FTS
+** "prefix=" option). And each index consists of multiple levels ("relative
+** levels").
+**
+** All three of these values (the language id, the specific index and the
+** level within the index) are encoded in 64-bit integer values stored
+** in the %_segdir table on disk. This function is used to convert three
+** separate component values into the single 64-bit integer value that
+** can be used to query the %_segdir table.
+**
+** Specifically, each language-id/index combination is allocated 1024
+** 64-bit integer level values ("absolute levels"). The main terms index
+** for language-id 0 is allocate values 0-1023. The first prefix index
+** (if any) for language-id 0 is allocated values 1024-2047. And so on.
+** Language 1 indexes are allocated immediately following language 0.
+**
+** So, for a system with nPrefix prefix indexes configured, the block of
+** absolute levels that corresponds to language-id iLangid and index
+** iIndex starts at absolute level ((iLangid * (nPrefix+1) + iIndex) * 1024).
+*/
+static sqlite3_int64 getAbsoluteLevel(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index in p->aIndex[] */
+  int iLevel                      /* Level of segments */
+){
+  sqlite3_int64 iBase;            /* First absolute level for iLangid/iIndex */
+  assert_fts3_nc( iLangid>=0 );
+  assert( p->nIndex>0 );
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  iBase = ((sqlite3_int64)iLangid * p->nIndex + iIndex) * FTS3_SEGDIR_MAXLEVEL;
+  return iBase + iLevel;
+}
+
+/*
+** Set *ppStmt to a statement handle that may be used to iterate through
+** all rows in the %_segdir table, from oldest to newest. If successful,
+** return SQLITE_OK. If an error occurs while preparing the statement,
+** return an SQLite error code.
+**
+** There is only ever one instance of this SQL statement compiled for
+** each FTS3 table.
+**
+** The statement returns the following columns from the %_segdir table:
+**
+**   0: idx
+**   1: start_block
+**   2: leaves_end_block
+**   3: end_block
+**   4: root
+*/
+SQLITE_PRIVATE int sqlite3Fts3AllSegdirs(
+  Fts3Table *p,                   /* FTS3 table */
+  int iLangid,                    /* Language being queried */
+  int iIndex,                     /* Index for p->aIndex[] */
+  int iLevel,                     /* Level to select (relative level) */
+  sqlite3_stmt **ppStmt           /* OUT: Compiled statement */
+){
+  int rc;
+  sqlite3_stmt *pStmt = 0;
+
+  assert( iLevel==FTS3_SEGCURSOR_ALL || iLevel>=0 );
+  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  if( iLevel<0 ){
+    /* "SELECT * FROM %_segdir WHERE level BETWEEN ? AND ? ORDER BY ..." */
+    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_RANGE, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
+      sqlite3_bind_int64(pStmt, 2,
+          getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
+      );
+    }
+  }else{
+    /* "SELECT * FROM %_segdir WHERE level = ? ORDER BY ..." */
+    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex,iLevel));
+    }
+  }
+  *ppStmt = pStmt;
+  return rc;
+}
+
+
+/*
+** Append a single varint to a PendingList buffer. SQLITE_OK is returned
+** if successful, or an SQLite error code otherwise.
+**
+** This function also serves to allocate the PendingList structure itself.
+** For example, to create a new PendingList structure containing two
+** varints:
+**
+**   PendingList *p = 0;
+**   fts3PendingListAppendVarint(&p, 1);
+**   fts3PendingListAppendVarint(&p, 2);
+*/
+static int fts3PendingListAppendVarint(
+  PendingList **pp,               /* IN/OUT: Pointer to PendingList struct */
+  sqlite3_int64 i                 /* Value to append to data */
+){
+  PendingList *p = *pp;
+
+  /* Allocate or grow the PendingList as required. */
+  if( !p ){
+    p = sqlite3_malloc64(sizeof(*p) + 100);
+    if( !p ){
+      return SQLITE_NOMEM;
+    }
+    p->nSpace = 100;
+    p->aData = (char *)&p[1];
+    p->nData = 0;
+  }
+  else if( p->nData+FTS3_VARINT_MAX+1>p->nSpace ){
+    i64 nNew = p->nSpace * 2;
+    p = sqlite3_realloc64(p, sizeof(*p) + nNew);
+    if( !p ){
+      sqlite3_free(*pp);
+      *pp = 0;
+      return SQLITE_NOMEM;
+    }
+    p->nSpace = (int)nNew;
+    p->aData = (char *)&p[1];
+  }
+
+  /* Append the new serialized varint to the end of the list. */
+  p->nData += sqlite3Fts3PutVarint(&p->aData[p->nData], i);
+  p->aData[p->nData] = '\0';
+  *pp = p;
+  return SQLITE_OK;
+}
+
+/*
+** Add a docid/column/position entry to a PendingList structure. Non-zero
+** is returned if the structure is sqlite3_realloced as part of adding
+** the entry. Otherwise, zero.
+**
+** If an OOM error occurs, *pRc is set to SQLITE_NOMEM before returning.
+** Zero is always returned in this case. Otherwise, if no OOM error occurs,
+** it is set to SQLITE_OK.
+*/
+static int fts3PendingListAppend(
+  PendingList **pp,               /* IN/OUT: PendingList structure */
+  sqlite3_int64 iDocid,           /* Docid for entry to add */
+  sqlite3_int64 iCol,             /* Column for entry to add */
+  sqlite3_int64 iPos,             /* Position of term for entry to add */
+  int *pRc                        /* OUT: Return code */
+){
+  PendingList *p = *pp;
+  int rc = SQLITE_OK;
+
+  assert( !p || p->iLastDocid<=iDocid );
+
+  if( !p || p->iLastDocid!=iDocid ){
+    u64 iDelta = (u64)iDocid - (u64)(p ? p->iLastDocid : 0);
+    if( p ){
+      assert( p->nData<p->nSpace );
+      assert( p->aData[p->nData]==0 );
+      p->nData++;
+    }
+    if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iDelta)) ){
+      goto pendinglistappend_out;
+    }
+    p->iLastCol = -1;
+    p->iLastPos = 0;
+    p->iLastDocid = iDocid;
+  }
+  if( iCol>0 && p->iLastCol!=iCol ){
+    if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, 1))
+     || SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iCol))
+    ){
+      goto pendinglistappend_out;
+    }
+    p->iLastCol = iCol;
+    p->iLastPos = 0;
+  }
+  if( iCol>=0 ){
+    assert( iPos>p->iLastPos || (iPos==0 && p->iLastPos==0) );
+    rc = fts3PendingListAppendVarint(&p, 2+iPos-p->iLastPos);
+    if( rc==SQLITE_OK ){
+      p->iLastPos = iPos;
+    }
+  }
+
+ pendinglistappend_out:
+  *pRc = rc;
+  if( p!=*pp ){
+    *pp = p;
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Free a PendingList object allocated by fts3PendingListAppend().
+*/
+static void fts3PendingListDelete(PendingList *pList){
+  sqlite3_free(pList);
+}
+
+/*
+** Add an entry to one of the pending-terms hash tables.
+*/
+static int fts3PendingTermsAddOne(
+  Fts3Table *p,
+  int iCol,
+  int iPos,
+  Fts3Hash *pHash,                /* Pending terms hash table to add entry to */
+  const char *zToken,
+  int nToken
+){
+  PendingList *pList;
+  int rc = SQLITE_OK;
+
+  pList = (PendingList *)fts3HashFind(pHash, zToken, nToken);
+  if( pList ){
+    p->nPendingData -= (pList->nData + nToken + sizeof(Fts3HashElem));
+  }
+  if( fts3PendingListAppend(&pList, p->iPrevDocid, iCol, iPos, &rc) ){
+    if( pList==fts3HashInsert(pHash, zToken, nToken, pList) ){
+      /* Malloc failed while inserting the new entry. This can only
+      ** happen if there was no previous entry for this token.
+      */
+      assert( 0==fts3HashFind(pHash, zToken, nToken) );
+      sqlite3_free(pList);
+      rc = SQLITE_NOMEM;
+    }
+  }
+  if( rc==SQLITE_OK ){
+    p->nPendingData += (pList->nData + nToken + sizeof(Fts3HashElem));
+  }
+  return rc;
+}
+
+/*
+** Tokenize the nul-terminated string zText and add all tokens to the
+** pending-terms hash-table. The docid used is that currently stored in
+** p->iPrevDocid, and the column is specified by argument iCol.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+*/
+static int fts3PendingTermsAdd(
+  Fts3Table *p,                   /* Table into which text will be inserted */
+  int iLangid,                    /* Language id to use */
+  const char *zText,              /* Text of document to be inserted */
+  int iCol,                       /* Column into which text is being inserted */
+  u32 *pnWord                     /* IN/OUT: Incr. by number tokens inserted */
+){
+  int rc;
+  int iStart = 0;
+  int iEnd = 0;
+  int iPos = 0;
+  int nWord = 0;
+
+  char const *zToken;
+  int nToken = 0;
+
+  sqlite3_tokenizer *pTokenizer = p->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  sqlite3_tokenizer_cursor *pCsr;
+  int (*xNext)(sqlite3_tokenizer_cursor *pCursor,
+      const char**,int*,int*,int*,int*);
+
+  assert( pTokenizer && pModule );
+
+  /* If the user has inserted a NULL value, this function may be called with
+  ** zText==0. In this case, add zero token entries to the hash table and
+  ** return early. */
+  if( zText==0 ){
+    *pnWord = 0;
+    return SQLITE_OK;
+  }
+
+  rc = sqlite3Fts3OpenTokenizer(pTokenizer, iLangid, zText, -1, &pCsr);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  xNext = pModule->xNext;
+  while( SQLITE_OK==rc
+      && SQLITE_OK==(rc = xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos))
+  ){
+    int i;
+    if( iPos>=nWord ) nWord = iPos+1;
+
+    /* Positions cannot be negative; we use -1 as a terminator internally.
+    ** Tokens must have a non-zero length.
+    */
+    if( iPos<0 || !zToken || nToken<=0 ){
+      rc = SQLITE_ERROR;
+      break;
+    }
+
+    /* Add the term to the terms index */
+    rc = fts3PendingTermsAddOne(
+        p, iCol, iPos, &p->aIndex[0].hPending, zToken, nToken
+    );
+
+    /* Add the term to each of the prefix indexes that it is not too
+    ** short for. */
+    for(i=1; rc==SQLITE_OK && i<p->nIndex; i++){
+      struct Fts3Index *pIndex = &p->aIndex[i];
+      if( nToken<pIndex->nPrefix ) continue;
+      rc = fts3PendingTermsAddOne(
+          p, iCol, iPos, &pIndex->hPending, zToken, pIndex->nPrefix
+      );
+    }
+  }
+
+  pModule->xClose(pCsr);
+  *pnWord += nWord;
+  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
+}
+
+/*
+** Calling this function indicates that subsequent calls to
+** fts3PendingTermsAdd() are to add term/position-list pairs for the
+** contents of the document with docid iDocid.
+*/
+static int fts3PendingTermsDocid(
+  Fts3Table *p,                   /* Full-text table handle */
+  int bDelete,                    /* True if this op is a delete */
+  int iLangid,                    /* Language id of row being written */
+  sqlite_int64 iDocid             /* Docid of row being written */
+){
+  assert( iLangid>=0 );
+  assert( bDelete==1 || bDelete==0 );
+
+  /* TODO(shess) Explore whether partially flushing the buffer on
+  ** forced-flush would provide better performance.  I suspect that if
+  ** we ordered the doclists by size and flushed the largest until the
+  ** buffer was half empty, that would let the less frequent terms
+  ** generate longer doclists.
+  */
+  if( iDocid<p->iPrevDocid
+   || (iDocid==p->iPrevDocid && p->bPrevDelete==0)
+   || p->iPrevLangid!=iLangid
+   || p->nPendingData>p->nMaxPendingData
+  ){
+    int rc = sqlite3Fts3PendingTermsFlush(p);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  p->iPrevDocid = iDocid;
+  p->iPrevLangid = iLangid;
+  p->bPrevDelete = bDelete;
+  return SQLITE_OK;
+}
+
+/*
+** Discard the contents of the pending-terms hash tables.
+*/
+SQLITE_PRIVATE void sqlite3Fts3PendingTermsClear(Fts3Table *p){
+  int i;
+  for(i=0; i<p->nIndex; i++){
+    Fts3HashElem *pElem;
+    Fts3Hash *pHash = &p->aIndex[i].hPending;
+    for(pElem=fts3HashFirst(pHash); pElem; pElem=fts3HashNext(pElem)){
+      PendingList *pList = (PendingList *)fts3HashData(pElem);
+      fts3PendingListDelete(pList);
+    }
+    fts3HashClear(pHash);
+  }
+  p->nPendingData = 0;
+}
+
+/*
+** This function is called by the xUpdate() method as part of an INSERT
+** operation. It adds entries for each term in the new record to the
+** pendingTerms hash table.
+**
+** Argument apVal is the same as the similarly named argument passed to
+** fts3InsertData(). Parameter iDocid is the docid of the new row.
+*/
+static int fts3InsertTerms(
+  Fts3Table *p,
+  int iLangid,
+  sqlite3_value **apVal,
+  u32 *aSz
+){
+  int i;                          /* Iterator variable */
+  for(i=2; i<p->nColumn+2; i++){
+    int iCol = i-2;
+    if( p->abNotindexed[iCol]==0 ){
+      const char *zText = (const char *)sqlite3_value_text(apVal[i]);
+      int rc = fts3PendingTermsAdd(p, iLangid, zText, iCol, &aSz[iCol]);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      aSz[p->nColumn] += sqlite3_value_bytes(apVal[i]);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is called by the xUpdate() method for an INSERT operation.
+** The apVal parameter is passed a copy of the apVal argument passed by
+** SQLite to the xUpdate() method. i.e:
+**
+**   apVal[0]                Not used for INSERT.
+**   apVal[1]                rowid
+**   apVal[2]                Left-most user-defined column
+**   ...
+**   apVal[p->nColumn+1]     Right-most user-defined column
+**   apVal[p->nColumn+2]     Hidden column with same name as table
+**   apVal[p->nColumn+3]     Hidden "docid" column (alias for rowid)
+**   apVal[p->nColumn+4]     Hidden languageid column
+*/
+static int fts3InsertData(
+  Fts3Table *p,                   /* Full-text table */
+  sqlite3_value **apVal,          /* Array of values to insert */
+  sqlite3_int64 *piDocid          /* OUT: Docid for row just inserted */
+){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pContentInsert;   /* INSERT INTO %_content VALUES(...) */
+
+  if( p->zContentTbl ){
+    sqlite3_value *pRowid = apVal[p->nColumn+3];
+    if( sqlite3_value_type(pRowid)==SQLITE_NULL ){
+      pRowid = apVal[1];
+    }
+    if( sqlite3_value_type(pRowid)!=SQLITE_INTEGER ){
+      return SQLITE_CONSTRAINT;
+    }
+    *piDocid = sqlite3_value_int64(pRowid);
+    return SQLITE_OK;
+  }
+
+  /* Locate the statement handle used to insert data into the %_content
+  ** table. The SQL for this statement is:
+  **
+  **   INSERT INTO %_content VALUES(?, ?, ?, ...)
+  **
+  ** The statement features N '?' variables, where N is the number of user
+  ** defined columns in the FTS3 table, plus one for the docid field.
+  */
+  rc = fts3SqlStmt(p, SQL_CONTENT_INSERT, &pContentInsert, &apVal[1]);
+  if( rc==SQLITE_OK && p->zLanguageid ){
+    rc = sqlite3_bind_int(
+        pContentInsert, p->nColumn+2,
+        sqlite3_value_int(apVal[p->nColumn+4])
+    );
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* There is a quirk here. The users INSERT statement may have specified
+  ** a value for the "rowid" field, for the "docid" field, or for both.
+  ** Which is a problem, since "rowid" and "docid" are aliases for the
+  ** same value. For example:
+  **
+  **   INSERT INTO fts3tbl(rowid, docid) VALUES(1, 2);
+  **
+  ** In FTS3, this is an error. It is an error to specify non-NULL values
+  ** for both docid and some other rowid alias.
+  */
+  if( SQLITE_NULL!=sqlite3_value_type(apVal[3+p->nColumn]) ){
+    if( SQLITE_NULL==sqlite3_value_type(apVal[0])
+     && SQLITE_NULL!=sqlite3_value_type(apVal[1])
+    ){
+      /* A rowid/docid conflict. */
+      return SQLITE_ERROR;
+    }
+    rc = sqlite3_bind_value(pContentInsert, 1, apVal[3+p->nColumn]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  /* Execute the statement to insert the record. Set *piDocid to the
+  ** new docid value.
+  */
+  sqlite3_step(pContentInsert);
+  rc = sqlite3_reset(pContentInsert);
+
+  *piDocid = sqlite3_last_insert_rowid(p->db);
+  return rc;
+}
+
+
+
+/*
+** Remove all data from the FTS3 table. Clear the hash table containing
+** pending terms.
+*/
+static int fts3DeleteAll(Fts3Table *p, int bContent){
+  int rc = SQLITE_OK;             /* Return code */
+
+  /* Discard the contents of the pending-terms hash table. */
+  sqlite3Fts3PendingTermsClear(p);
+
+  /* Delete everything from the shadow tables. Except, leave %_content as
+  ** is if bContent is false.  */
+  assert( p->zContentTbl==0 || bContent==0 );
+  if( bContent ) fts3SqlExec(&rc, p, SQL_DELETE_ALL_CONTENT, 0);
+  fts3SqlExec(&rc, p, SQL_DELETE_ALL_SEGMENTS, 0);
+  fts3SqlExec(&rc, p, SQL_DELETE_ALL_SEGDIR, 0);
+  if( p->bHasDocsize ){
+    fts3SqlExec(&rc, p, SQL_DELETE_ALL_DOCSIZE, 0);
+  }
+  if( p->bHasStat ){
+    fts3SqlExec(&rc, p, SQL_DELETE_ALL_STAT, 0);
+  }
+  return rc;
+}
+
+/*
+**
+*/
+static int langidFromSelect(Fts3Table *p, sqlite3_stmt *pSelect){
+  int iLangid = 0;
+  if( p->zLanguageid ) iLangid = sqlite3_column_int(pSelect, p->nColumn+1);
+  return iLangid;
+}
+
+/*
+** The first element in the apVal[] array is assumed to contain the docid
+** (an integer) of a row about to be deleted. Remove all terms from the
+** full-text index.
+*/
+static void fts3DeleteTerms(
+  int *pRC,               /* Result code */
+  Fts3Table *p,           /* The FTS table to delete from */
+  sqlite3_value *pRowid,  /* The docid to be deleted */
+  u32 *aSz,               /* Sizes of deleted document written here */
+  int *pbFound            /* OUT: Set to true if row really does exist */
+){
+  int rc;
+  sqlite3_stmt *pSelect;
+
+  assert( *pbFound==0 );
+  if( *pRC ) return;
+  rc = fts3SqlStmt(p, SQL_SELECT_CONTENT_BY_ROWID, &pSelect, &pRowid);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pSelect) ){
+      int i;
+      int iLangid = langidFromSelect(p, pSelect);
+      i64 iDocid = sqlite3_column_int64(pSelect, 0);
+      rc = fts3PendingTermsDocid(p, 1, iLangid, iDocid);
+      for(i=1; rc==SQLITE_OK && i<=p->nColumn; i++){
+        int iCol = i-1;
+        if( p->abNotindexed[iCol]==0 ){
+          const char *zText = (const char *)sqlite3_column_text(pSelect, i);
+          rc = fts3PendingTermsAdd(p, iLangid, zText, -1, &aSz[iCol]);
+          aSz[p->nColumn] += sqlite3_column_bytes(pSelect, i);
+        }
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3_reset(pSelect);
+        *pRC = rc;
+        return;
+      }
+      *pbFound = 1;
+    }
+    rc = sqlite3_reset(pSelect);
+  }else{
+    sqlite3_reset(pSelect);
+  }
+  *pRC = rc;
+}
+
+/*
+** Forward declaration to account for the circular dependency between
+** functions fts3SegmentMerge() and fts3AllocateSegdirIdx().
+*/
+static int fts3SegmentMerge(Fts3Table *, int, int, int);
+
+/*
+** This function allocates a new level iLevel index in the segdir table.
+** Usually, indexes are allocated within a level sequentially starting
+** with 0, so the allocated index is one greater than the value returned
+** by:
+**
+**   SELECT max(idx) FROM %_segdir WHERE level = :iLevel
+**
+** However, if there are already FTS3_MERGE_COUNT indexes at the requested
+** level, they are merged into a single level (iLevel+1) segment and the
+** allocated index is 0.
+**
+** If successful, *piIdx is set to the allocated index slot and SQLITE_OK
+** returned. Otherwise, an SQLite error code is returned.
+*/
+static int fts3AllocateSegdirIdx(
+  Fts3Table *p,
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index for p->aIndex */
+  int iLevel,
+  int *piIdx
+){
+  int rc;                         /* Return Code */
+  sqlite3_stmt *pNextIdx;         /* Query for next idx at level iLevel */
+  int iNext = 0;                  /* Result of query pNextIdx */
+
+  assert( iLangid>=0 );
+  assert( p->nIndex>=1 );
+
+  /* Set variable iNext to the next available segdir index at level iLevel. */
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pNextIdx, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(
+        pNextIdx, 1, getAbsoluteLevel(p, iLangid, iIndex, iLevel)
+    );
+    if( SQLITE_ROW==sqlite3_step(pNextIdx) ){
+      iNext = sqlite3_column_int(pNextIdx, 0);
+    }
+    rc = sqlite3_reset(pNextIdx);
+  }
+
+  if( rc==SQLITE_OK ){
+    /* If iNext is FTS3_MERGE_COUNT, indicating that level iLevel is already
+    ** full, merge all segments in level iLevel into a single iLevel+1
+    ** segment and allocate (newly freed) index 0 at level iLevel. Otherwise,
+    ** if iNext is less than FTS3_MERGE_COUNT, allocate index iNext.
+    */
+    if( iNext>=MergeCount(p) ){
+      fts3LogMerge(16, getAbsoluteLevel(p, iLangid, iIndex, iLevel));
+      rc = fts3SegmentMerge(p, iLangid, iIndex, iLevel);
+      *piIdx = 0;
+    }else{
+      *piIdx = iNext;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The %_segments table is declared as follows:
+**
+**   CREATE TABLE %_segments(blockid INTEGER PRIMARY KEY, block BLOB)
+**
+** This function reads data from a single row of the %_segments table. The
+** specific row is identified by the iBlockid parameter. If paBlob is not
+** NULL, then a buffer is allocated using sqlite3_malloc() and populated
+** with the contents of the blob stored in the "block" column of the
+** identified table row is. Whether or not paBlob is NULL, *pnBlob is set
+** to the size of the blob in bytes before returning.
+**
+** If an error occurs, or the table does not contain the specified row,
+** an SQLite error code is returned. Otherwise, SQLITE_OK is returned. If
+** paBlob is non-NULL, then it is the responsibility of the caller to
+** eventually free the returned buffer.
+**
+** This function may leave an open sqlite3_blob* handle in the
+** Fts3Table.pSegments variable. This handle is reused by subsequent calls
+** to this function. The handle may be closed by calling the
+** sqlite3Fts3SegmentsClose() function. Reusing a blob handle is a handy
+** performance improvement, but the blob handle should always be closed
+** before control is returned to the user (to prevent a lock being held
+** on the database file for longer than necessary). Thus, any virtual table
+** method (xFilter etc.) that may directly or indirectly call this function
+** must call sqlite3Fts3SegmentsClose() before returning.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ReadBlock(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iBlockid,         /* Access the row with blockid=$iBlockid */
+  char **paBlob,                  /* OUT: Blob data in malloc'd buffer */
+  int *pnBlob,                    /* OUT: Size of blob data */
+  int *pnLoad                     /* OUT: Bytes actually loaded */
+){
+  int rc;                         /* Return code */
+
+  /* pnBlob must be non-NULL. paBlob may be NULL or non-NULL. */
+  assert( pnBlob );
+
+  if( p->pSegments ){
+    rc = sqlite3_blob_reopen(p->pSegments, iBlockid);
+  }else{
+    if( 0==p->zSegmentsTbl ){
+      p->zSegmentsTbl = sqlite3_mprintf("%s_segments", p->zName);
+      if( 0==p->zSegmentsTbl ) return SQLITE_NOMEM;
+    }
+    rc = sqlite3_blob_open(
+       p->db, p->zDb, p->zSegmentsTbl, "block", iBlockid, 0, &p->pSegments
+    );
+  }
+
+  if( rc==SQLITE_OK ){
+    int nByte = sqlite3_blob_bytes(p->pSegments);
+    *pnBlob = nByte;
+    if( paBlob ){
+      char *aByte = sqlite3_malloc64((i64)nByte + FTS3_NODE_PADDING);
+      if( !aByte ){
+        rc = SQLITE_NOMEM;
+      }else{
+        if( pnLoad && nByte>(FTS3_NODE_CHUNK_THRESHOLD) ){
+          nByte = FTS3_NODE_CHUNKSIZE;
+          *pnLoad = nByte;
+        }
+        rc = sqlite3_blob_read(p->pSegments, aByte, nByte, 0);
+        memset(&aByte[nByte], 0, FTS3_NODE_PADDING);
+        if( rc!=SQLITE_OK ){
+          sqlite3_free(aByte);
+          aByte = 0;
+        }
+      }
+      *paBlob = aByte;
+    }
+  }else if( rc==SQLITE_ERROR ){
+    rc = FTS_CORRUPT_VTAB;
+  }
+
+  return rc;
+}
+
+/*
+** Close the blob handle at p->pSegments, if it is open. See comments above
+** the sqlite3Fts3ReadBlock() function for details.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SegmentsClose(Fts3Table *p){
+  sqlite3_blob_close(p->pSegments);
+  p->pSegments = 0;
+}
+
+static int fts3SegReaderIncrRead(Fts3SegReader *pReader){
+  int nRead;                      /* Number of bytes to read */
+  int rc;                         /* Return code */
+
+  nRead = MIN(pReader->nNode - pReader->nPopulate, FTS3_NODE_CHUNKSIZE);
+  rc = sqlite3_blob_read(
+      pReader->pBlob,
+      &pReader->aNode[pReader->nPopulate],
+      nRead,
+      pReader->nPopulate
+  );
+
+  if( rc==SQLITE_OK ){
+    pReader->nPopulate += nRead;
+    memset(&pReader->aNode[pReader->nPopulate], 0, FTS3_NODE_PADDING);
+    if( pReader->nPopulate==pReader->nNode ){
+      sqlite3_blob_close(pReader->pBlob);
+      pReader->pBlob = 0;
+      pReader->nPopulate = 0;
+    }
+  }
+  return rc;
+}
+
+static int fts3SegReaderRequire(Fts3SegReader *pReader, char *pFrom, int nByte){
+  int rc = SQLITE_OK;
+  assert( !pReader->pBlob
+       || (pFrom>=pReader->aNode && pFrom<&pReader->aNode[pReader->nNode])
+  );
+  while( pReader->pBlob && rc==SQLITE_OK
+     &&  (pFrom - pReader->aNode + nByte)>pReader->nPopulate
+  ){
+    rc = fts3SegReaderIncrRead(pReader);
+  }
+  return rc;
+}
+
+/*
+** Set an Fts3SegReader cursor to point at EOF.
+*/
+static void fts3SegReaderSetEof(Fts3SegReader *pSeg){
+  if( !fts3SegReaderIsRootOnly(pSeg) ){
+    sqlite3_free(pSeg->aNode);
+    sqlite3_blob_close(pSeg->pBlob);
+    pSeg->pBlob = 0;
+  }
+  pSeg->aNode = 0;
+}
+
+/*
+** Move the iterator passed as the first argument to the next term in the
+** segment. If successful, SQLITE_OK is returned. If there is no next term,
+** SQLITE_DONE. Otherwise, an SQLite error code.
+*/
+static int fts3SegReaderNext(
+  Fts3Table *p,
+  Fts3SegReader *pReader,
+  int bIncr
+){
+  int rc;                         /* Return code of various sub-routines */
+  char *pNext;                    /* Cursor variable */
+  int nPrefix;                    /* Number of bytes in term prefix */
+  int nSuffix;                    /* Number of bytes in term suffix */
+
+  if( !pReader->aDoclist ){
+    pNext = pReader->aNode;
+  }else{
+    pNext = &pReader->aDoclist[pReader->nDoclist];
+  }
+
+  if( !pNext || pNext>=&pReader->aNode[pReader->nNode] ){
+
+    if( fts3SegReaderIsPending(pReader) ){
+      Fts3HashElem *pElem = *(pReader->ppNextElem);
+      sqlite3_free(pReader->aNode);
+      pReader->aNode = 0;
+      if( pElem ){
+        char *aCopy;
+        PendingList *pList = (PendingList *)fts3HashData(pElem);
+        int nCopy = pList->nData+1;
+
+        int nTerm = fts3HashKeysize(pElem);
+        if( (nTerm+1)>pReader->nTermAlloc ){
+          sqlite3_free(pReader->zTerm);
+          pReader->zTerm = (char*)sqlite3_malloc64(((i64)nTerm+1)*2);
+          if( !pReader->zTerm ) return SQLITE_NOMEM;
+          pReader->nTermAlloc = (nTerm+1)*2;
+        }
+        memcpy(pReader->zTerm, fts3HashKey(pElem), nTerm);
+        pReader->zTerm[nTerm] = '\0';
+        pReader->nTerm = nTerm;
+
+        aCopy = (char*)sqlite3_malloc64(nCopy);
+        if( !aCopy ) return SQLITE_NOMEM;
+        memcpy(aCopy, pList->aData, nCopy);
+        pReader->nNode = pReader->nDoclist = nCopy;
+        pReader->aNode = pReader->aDoclist = aCopy;
+        pReader->ppNextElem++;
+        assert( pReader->aNode );
+      }
+      return SQLITE_OK;
+    }
+
+    fts3SegReaderSetEof(pReader);
+
+    /* If iCurrentBlock>=iLeafEndBlock, this is an EOF condition. All leaf
+    ** blocks have already been traversed.  */
+#ifdef CORRUPT_DB
+    assert( pReader->iCurrentBlock<=pReader->iLeafEndBlock || CORRUPT_DB );
+#endif
+    if( pReader->iCurrentBlock>=pReader->iLeafEndBlock ){
+      return SQLITE_OK;
+    }
+
+    rc = sqlite3Fts3ReadBlock(
+        p, ++pReader->iCurrentBlock, &pReader->aNode, &pReader->nNode,
+        (bIncr ? &pReader->nPopulate : 0)
+    );
+    if( rc!=SQLITE_OK ) return rc;
+    assert( pReader->pBlob==0 );
+    if( bIncr && pReader->nPopulate<pReader->nNode ){
+      pReader->pBlob = p->pSegments;
+      p->pSegments = 0;
+    }
+    pNext = pReader->aNode;
+  }
+
+  assert( !fts3SegReaderIsPending(pReader) );
+
+  rc = fts3SegReaderRequire(pReader, pNext, FTS3_VARINT_MAX*2);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Because of the FTS3_NODE_PADDING bytes of padding, the following is
+  ** safe (no risk of overread) even if the node data is corrupted. */
+  pNext += fts3GetVarint32(pNext, &nPrefix);
+  pNext += fts3GetVarint32(pNext, &nSuffix);
+  if( nSuffix<=0
+   || (&pReader->aNode[pReader->nNode] - pNext)<nSuffix
+   || nPrefix>pReader->nTerm
+  ){
+    return FTS_CORRUPT_VTAB;
+  }
+
+  /* Both nPrefix and nSuffix were read by fts3GetVarint32() and so are
+  ** between 0 and 0x7FFFFFFF. But the sum of the two may cause integer
+  ** overflow - hence the (i64) casts.  */
+  if( (i64)nPrefix+nSuffix>(i64)pReader->nTermAlloc ){
+    i64 nNew = ((i64)nPrefix+nSuffix)*2;
+    char *zNew = sqlite3_realloc64(pReader->zTerm, nNew);
+    if( !zNew ){
+      return SQLITE_NOMEM;
+    }
+    pReader->zTerm = zNew;
+    pReader->nTermAlloc = nNew;
+  }
+
+  rc = fts3SegReaderRequire(pReader, pNext, nSuffix+FTS3_VARINT_MAX);
+  if( rc!=SQLITE_OK ) return rc;
+
+  memcpy(&pReader->zTerm[nPrefix], pNext, nSuffix);
+  pReader->nTerm = nPrefix+nSuffix;
+  pNext += nSuffix;
+  pNext += fts3GetVarint32(pNext, &pReader->nDoclist);
+  pReader->aDoclist = pNext;
+  pReader->pOffsetList = 0;
+
+  /* Check that the doclist does not appear to extend past the end of the
+  ** b-tree node. And that the final byte of the doclist is 0x00. If either
+  ** of these statements is untrue, then the data structure is corrupt.
+  */
+  if( pReader->nDoclist > pReader->nNode-(pReader->aDoclist-pReader->aNode)
+   || (pReader->nPopulate==0 && pReader->aDoclist[pReader->nDoclist-1])
+   || pReader->nDoclist==0
+  ){
+    return FTS_CORRUPT_VTAB;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Set the SegReader to point to the first docid in the doclist associated
+** with the current term.
+*/
+static int fts3SegReaderFirstDocid(Fts3Table *pTab, Fts3SegReader *pReader){
+  int rc = SQLITE_OK;
+  assert( pReader->aDoclist );
+  assert( !pReader->pOffsetList );
+  if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
+    u8 bEof = 0;
+    pReader->iDocid = 0;
+    pReader->nOffsetList = 0;
+    sqlite3Fts3DoclistPrev(0,
+        pReader->aDoclist, pReader->nDoclist, &pReader->pOffsetList,
+        &pReader->iDocid, &pReader->nOffsetList, &bEof
+    );
+  }else{
+    rc = fts3SegReaderRequire(pReader, pReader->aDoclist, FTS3_VARINT_MAX);
+    if( rc==SQLITE_OK ){
+      int n = sqlite3Fts3GetVarint(pReader->aDoclist, &pReader->iDocid);
+      pReader->pOffsetList = &pReader->aDoclist[n];
+    }
+  }
+  return rc;
+}
+
+/*
+** Advance the SegReader to point to the next docid in the doclist
+** associated with the current term.
+**
+** If arguments ppOffsetList and pnOffsetList are not NULL, then
+** *ppOffsetList is set to point to the first column-offset list
+** in the doclist entry (i.e. immediately past the docid varint).
+** *pnOffsetList is set to the length of the set of column-offset
+** lists, not including the nul-terminator byte. For example:
+*/
+static int fts3SegReaderNextDocid(
+  Fts3Table *pTab,
+  Fts3SegReader *pReader,         /* Reader to advance to next docid */
+  char **ppOffsetList,            /* OUT: Pointer to current position-list */
+  int *pnOffsetList               /* OUT: Length of *ppOffsetList in bytes */
+){
+  int rc = SQLITE_OK;
+  char *p = pReader->pOffsetList;
+  char c = 0;
+
+  assert( p );
+
+  if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
+    /* A pending-terms seg-reader for an FTS4 table that uses order=desc.
+    ** Pending-terms doclists are always built up in ascending order, so
+    ** we have to iterate through them backwards here. */
+    u8 bEof = 0;
+    if( ppOffsetList ){
+      *ppOffsetList = pReader->pOffsetList;
+      *pnOffsetList = pReader->nOffsetList - 1;
+    }
+    sqlite3Fts3DoclistPrev(0,
+        pReader->aDoclist, pReader->nDoclist, &p, &pReader->iDocid,
+        &pReader->nOffsetList, &bEof
+    );
+    if( bEof ){
+      pReader->pOffsetList = 0;
+    }else{
+      pReader->pOffsetList = p;
+    }
+  }else{
+    char *pEnd = &pReader->aDoclist[pReader->nDoclist];
+
+    /* Pointer p currently points at the first byte of an offset list. The
+    ** following block advances it to point one byte past the end of
+    ** the same offset list. */
+    while( 1 ){
+
+      /* The following line of code (and the "p++" below the while() loop) is
+      ** normally all that is required to move pointer p to the desired
+      ** position. The exception is if this node is being loaded from disk
+      ** incrementally and pointer "p" now points to the first byte past
+      ** the populated part of pReader->aNode[].
+      */
+      while( *p | c ) c = *p++ & 0x80;
+      assert( *p==0 );
+
+      if( pReader->pBlob==0 || p<&pReader->aNode[pReader->nPopulate] ) break;
+      rc = fts3SegReaderIncrRead(pReader);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    p++;
+
+    /* If required, populate the output variables with a pointer to and the
+    ** size of the previous offset-list.
+    */
+    if( ppOffsetList ){
+      *ppOffsetList = pReader->pOffsetList;
+      *pnOffsetList = (int)(p - pReader->pOffsetList - 1);
+    }
+
+    /* List may have been edited in place by fts3EvalNearTrim() */
+    while( p<pEnd && *p==0 ) p++;
+
+    /* If there are no more entries in the doclist, set pOffsetList to
+    ** NULL. Otherwise, set Fts3SegReader.iDocid to the next docid and
+    ** Fts3SegReader.pOffsetList to point to the next offset list before
+    ** returning.
+    */
+    if( p>=pEnd ){
+      pReader->pOffsetList = 0;
+    }else{
+      rc = fts3SegReaderRequire(pReader, p, FTS3_VARINT_MAX);
+      if( rc==SQLITE_OK ){
+        u64 iDelta;
+        pReader->pOffsetList = p + sqlite3Fts3GetVarintU(p, &iDelta);
+        if( pTab->bDescIdx ){
+          pReader->iDocid = (i64)((u64)pReader->iDocid - iDelta);
+        }else{
+          pReader->iDocid = (i64)((u64)pReader->iDocid + iDelta);
+        }
+      }
+    }
+  }
+
+  return rc;
+}
+
+
+SQLITE_PRIVATE int sqlite3Fts3MsrOvfl(
+  Fts3Cursor *pCsr,
+  Fts3MultiSegReader *pMsr,
+  int *pnOvfl
+){
+  Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
+  int nOvfl = 0;
+  int ii;
+  int rc = SQLITE_OK;
+  int pgsz = p->nPgsz;
+
+  assert( p->bFts4 );
+  assert( pgsz>0 );
+
+  for(ii=0; rc==SQLITE_OK && ii<pMsr->nSegment; ii++){
+    Fts3SegReader *pReader = pMsr->apSegment[ii];
+    if( !fts3SegReaderIsPending(pReader)
+     && !fts3SegReaderIsRootOnly(pReader)
+    ){
+      sqlite3_int64 jj;
+      for(jj=pReader->iStartBlock; jj<=pReader->iLeafEndBlock; jj++){
+        int nBlob;
+        rc = sqlite3Fts3ReadBlock(p, jj, 0, &nBlob, 0);
+        if( rc!=SQLITE_OK ) break;
+        if( (nBlob+35)>pgsz ){
+          nOvfl += (nBlob + 34)/pgsz;
+        }
+      }
+    }
+  }
+  *pnOvfl = nOvfl;
+  return rc;
+}
+
+/*
+** Free all allocations associated with the iterator passed as the
+** second argument.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFree(Fts3SegReader *pReader){
+  if( pReader ){
+    sqlite3_free(pReader->zTerm);
+    if( !fts3SegReaderIsRootOnly(pReader) ){
+      sqlite3_free(pReader->aNode);
+    }
+    sqlite3_blob_close(pReader->pBlob);
+  }
+  sqlite3_free(pReader);
+}
+
+/*
+** Allocate a new SegReader object.
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderNew(
+  int iAge,                       /* Segment "age". */
+  int bLookup,                    /* True for a lookup only */
+  sqlite3_int64 iStartLeaf,       /* First leaf to traverse */
+  sqlite3_int64 iEndLeaf,         /* Final leaf to traverse */
+  sqlite3_int64 iEndBlock,        /* Final block of segment */
+  const char *zRoot,              /* Buffer containing root node */
+  int nRoot,                      /* Size of buffer containing root node */
+  Fts3SegReader **ppReader        /* OUT: Allocated Fts3SegReader */
+){
+  Fts3SegReader *pReader;         /* Newly allocated SegReader object */
+  int nExtra = 0;                 /* Bytes to allocate segment root node */
+
+  assert( zRoot!=0 || nRoot==0 );
+#ifdef CORRUPT_DB
+  assert( zRoot!=0 || CORRUPT_DB );
+#endif
+
+  if( iStartLeaf==0 ){
+    if( iEndLeaf!=0 ) return FTS_CORRUPT_VTAB;
+    nExtra = nRoot + FTS3_NODE_PADDING;
+  }
+
+  pReader = (Fts3SegReader *)sqlite3_malloc64(sizeof(Fts3SegReader) + nExtra);
+  if( !pReader ){
+    return SQLITE_NOMEM;
+  }
+  memset(pReader, 0, sizeof(Fts3SegReader));
+  pReader->iIdx = iAge;
+  pReader->bLookup = bLookup!=0;
+  pReader->iStartBlock = iStartLeaf;
+  pReader->iLeafEndBlock = iEndLeaf;
+  pReader->iEndBlock = iEndBlock;
+
+  if( nExtra ){
+    /* The entire segment is stored in the root node. */
+    pReader->aNode = (char *)&pReader[1];
+    pReader->rootOnly = 1;
+    pReader->nNode = nRoot;
+    if( nRoot ) memcpy(pReader->aNode, zRoot, nRoot);
+    memset(&pReader->aNode[nRoot], 0, FTS3_NODE_PADDING);
+  }else{
+    pReader->iCurrentBlock = iStartLeaf-1;
+  }
+  *ppReader = pReader;
+  return SQLITE_OK;
+}
+
+/*
+** This is a comparison function used as a qsort() callback when sorting
+** an array of pending terms by term. This occurs as part of flushing
+** the contents of the pending-terms hash table to the database.
+*/
+static int SQLITE_CDECL fts3CompareElemByTerm(
+  const void *lhs,
+  const void *rhs
+){
+  char *z1 = fts3HashKey(*(Fts3HashElem **)lhs);
+  char *z2 = fts3HashKey(*(Fts3HashElem **)rhs);
+  int n1 = fts3HashKeysize(*(Fts3HashElem **)lhs);
+  int n2 = fts3HashKeysize(*(Fts3HashElem **)rhs);
+
+  int n = (n1<n2 ? n1 : n2);
+  int c = memcmp(z1, z2, n);
+  if( c==0 ){
+    c = n1 - n2;
+  }
+  return c;
+}
+
+/*
+** This function is used to allocate an Fts3SegReader that iterates through
+** a subset of the terms stored in the Fts3Table.pendingTerms array.
+**
+** If the isPrefixIter parameter is zero, then the returned SegReader iterates
+** through each term in the pending-terms table. Or, if isPrefixIter is
+** non-zero, it iterates through each term and its prefixes. For example, if
+** the pending terms hash table contains the terms "sqlite", "mysql" and
+** "firebird", then the iterator visits the following 'terms' (in the order
+** shown):
+**
+**   f fi fir fire fireb firebi firebir firebird
+**   m my mys mysq mysql
+**   s sq sql sqli sqlit sqlite
+**
+** Whereas if isPrefixIter is zero, the terms visited are:
+**
+**   firebird mysql sqlite
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderPending(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iIndex,                     /* Index for p->aIndex */
+  const char *zTerm,              /* Term to search for */
+  int nTerm,                      /* Size of buffer zTerm */
+  int bPrefix,                    /* True for a prefix iterator */
+  Fts3SegReader **ppReader        /* OUT: SegReader for pending-terms */
+){
+  Fts3SegReader *pReader = 0;     /* Fts3SegReader object to return */
+  Fts3HashElem *pE;               /* Iterator variable */
+  Fts3HashElem **aElem = 0;       /* Array of term hash entries to scan */
+  int nElem = 0;                  /* Size of array at aElem */
+  int rc = SQLITE_OK;             /* Return Code */
+  Fts3Hash *pHash;
+
+  pHash = &p->aIndex[iIndex].hPending;
+  if( bPrefix ){
+    int nAlloc = 0;               /* Size of allocated array at aElem */
+
+    for(pE=fts3HashFirst(pHash); pE; pE=fts3HashNext(pE)){
+      char *zKey = (char *)fts3HashKey(pE);
+      int nKey = fts3HashKeysize(pE);
+      if( nTerm==0 || (nKey>=nTerm && 0==memcmp(zKey, zTerm, nTerm)) ){
+        if( nElem==nAlloc ){
+          Fts3HashElem **aElem2;
+          nAlloc += 16;
+          aElem2 = (Fts3HashElem **)sqlite3_realloc64(
+              aElem, nAlloc*sizeof(Fts3HashElem *)
+          );
+          if( !aElem2 ){
+            rc = SQLITE_NOMEM;
+            nElem = 0;
+            break;
+          }
+          aElem = aElem2;
+        }
+
+        aElem[nElem++] = pE;
+      }
+    }
+
+    /* If more than one term matches the prefix, sort the Fts3HashElem
+    ** objects in term order using qsort(). This uses the same comparison
+    ** callback as is used when flushing terms to disk.
+    */
+    if( nElem>1 ){
+      qsort(aElem, nElem, sizeof(Fts3HashElem *), fts3CompareElemByTerm);
+    }
+
+  }else{
+    /* The query is a simple term lookup that matches at most one term in
+    ** the index. All that is required is a straight hash-lookup.
+    **
+    ** Because the stack address of pE may be accessed via the aElem pointer
+    ** below, the "Fts3HashElem *pE" must be declared so that it is valid
+    ** within this entire function, not just this "else{...}" block.
+    */
+    pE = fts3HashFindElem(pHash, zTerm, nTerm);
+    if( pE ){
+      aElem = &pE;
+      nElem = 1;
+    }
+  }
+
+  if( nElem>0 ){
+    sqlite3_int64 nByte;
+    nByte = sizeof(Fts3SegReader) + (nElem+1)*sizeof(Fts3HashElem *);
+    pReader = (Fts3SegReader *)sqlite3_malloc64(nByte);
+    if( !pReader ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pReader, 0, nByte);
+      pReader->iIdx = 0x7FFFFFFF;
+      pReader->ppNextElem = (Fts3HashElem **)&pReader[1];
+      memcpy(pReader->ppNextElem, aElem, nElem*sizeof(Fts3HashElem *));
+    }
+  }
+
+  if( bPrefix ){
+    sqlite3_free(aElem);
+  }
+  *ppReader = pReader;
+  return rc;
+}
+
+/*
+** Compare the entries pointed to by two Fts3SegReader structures.
+** Comparison is as follows:
+**
+**   1) EOF is greater than not EOF.
+**
+**   2) The current terms (if any) are compared using memcmp(). If one
+**      term is a prefix of another, the longer term is considered the
+**      larger.
+**
+**   3) By segment age. An older segment is considered larger.
+*/
+static int fts3SegReaderCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc;
+  if( pLhs->aNode && pRhs->aNode ){
+    int rc2 = pLhs->nTerm - pRhs->nTerm;
+    if( rc2<0 ){
+      rc = memcmp(pLhs->zTerm, pRhs->zTerm, pLhs->nTerm);
+    }else{
+      rc = memcmp(pLhs->zTerm, pRhs->zTerm, pRhs->nTerm);
+    }
+    if( rc==0 ){
+      rc = rc2;
+    }
+  }else{
+    rc = (pLhs->aNode==0) - (pRhs->aNode==0);
+  }
+  if( rc==0 ){
+    rc = pRhs->iIdx - pLhs->iIdx;
+  }
+  assert_fts3_nc( rc!=0 );
+  return rc;
+}
+
+/*
+** A different comparison function for SegReader structures. In this
+** version, it is assumed that each SegReader points to an entry in
+** a doclist for identical terms. Comparison is made as follows:
+**
+**   1) EOF (end of doclist in this case) is greater than not EOF.
+**
+**   2) By current docid.
+**
+**   3) By segment age. An older segment is considered larger.
+*/
+static int fts3SegReaderDoclistCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
+  if( rc==0 ){
+    if( pLhs->iDocid==pRhs->iDocid ){
+      rc = pRhs->iIdx - pLhs->iIdx;
+    }else{
+      rc = (pLhs->iDocid > pRhs->iDocid) ? 1 : -1;
+    }
+  }
+  assert( pLhs->aNode && pRhs->aNode );
+  return rc;
+}
+static int fts3SegReaderDoclistCmpRev(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
+  if( rc==0 ){
+    if( pLhs->iDocid==pRhs->iDocid ){
+      rc = pRhs->iIdx - pLhs->iIdx;
+    }else{
+      rc = (pLhs->iDocid < pRhs->iDocid) ? 1 : -1;
+    }
+  }
+  assert( pLhs->aNode && pRhs->aNode );
+  return rc;
+}
+
+/*
+** Compare the term that the Fts3SegReader object passed as the first argument
+** points to with the term specified by arguments zTerm and nTerm.
+**
+** If the pSeg iterator is already at EOF, return 0. Otherwise, return
+** -ve if the pSeg term is less than zTerm/nTerm, 0 if the two terms are
+** equal, or +ve if the pSeg term is greater than zTerm/nTerm.
+*/
+static int fts3SegReaderTermCmp(
+  Fts3SegReader *pSeg,            /* Segment reader object */
+  const char *zTerm,              /* Term to compare to */
+  int nTerm                       /* Size of term zTerm in bytes */
+){
+  int res = 0;
+  if( pSeg->aNode ){
+    if( pSeg->nTerm>nTerm ){
+      res = memcmp(pSeg->zTerm, zTerm, nTerm);
+    }else{
+      res = memcmp(pSeg->zTerm, zTerm, pSeg->nTerm);
+    }
+    if( res==0 ){
+      res = pSeg->nTerm-nTerm;
+    }
+  }
+  return res;
+}
+
+/*
+** Argument apSegment is an array of nSegment elements. It is known that
+** the final (nSegment-nSuspect) members are already in sorted order
+** (according to the comparison function provided). This function shuffles
+** the array around until all entries are in sorted order.
+*/
+static void fts3SegReaderSort(
+  Fts3SegReader **apSegment,                     /* Array to sort entries of */
+  int nSegment,                                  /* Size of apSegment array */
+  int nSuspect,                                  /* Unsorted entry count */
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *)  /* Comparison function */
+){
+  int i;                          /* Iterator variable */
+
+  assert( nSuspect<=nSegment );
+
+  if( nSuspect==nSegment ) nSuspect--;
+  for(i=nSuspect-1; i>=0; i--){
+    int j;
+    for(j=i; j<(nSegment-1); j++){
+      Fts3SegReader *pTmp;
+      if( xCmp(apSegment[j], apSegment[j+1])<0 ) break;
+      pTmp = apSegment[j+1];
+      apSegment[j+1] = apSegment[j];
+      apSegment[j] = pTmp;
+    }
+  }
+
+#ifndef NDEBUG
+  /* Check that the list really is sorted now. */
+  for(i=0; i<(nSuspect-1); i++){
+    assert( xCmp(apSegment[i], apSegment[i+1])<0 );
+  }
+#endif
+}
+
+/*
+** Insert a record into the %_segments table.
+*/
+static int fts3WriteSegment(
+  Fts3Table *p,                   /* Virtual table handle */
+  sqlite3_int64 iBlock,           /* Block id for new block */
+  char *z,                        /* Pointer to buffer containing block data */
+  int n                           /* Size of buffer z in bytes */
+){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_INSERT_SEGMENTS, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iBlock);
+    sqlite3_bind_blob(pStmt, 2, z, n, SQLITE_STATIC);
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+    sqlite3_bind_null(pStmt, 2);
+  }
+  return rc;
+}
+
+/*
+** Find the largest relative level number in the table. If successful, set
+** *pnMax to this value and return SQLITE_OK. Otherwise, if an error occurs,
+** set *pnMax to zero and return an SQLite error code.
+*/
+SQLITE_PRIVATE int sqlite3Fts3MaxLevel(Fts3Table *p, int *pnMax){
+  int rc;
+  int mxLevel = 0;
+  sqlite3_stmt *pStmt = 0;
+
+  rc = fts3SqlStmt(p, SQL_SELECT_MXLEVEL, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      mxLevel = sqlite3_column_int(pStmt, 0);
+    }
+    rc = sqlite3_reset(pStmt);
+  }
+  *pnMax = mxLevel;
+  return rc;
+}
+
+/*
+** Insert a record into the %_segdir table.
+*/
+static int fts3WriteSegdir(
+  Fts3Table *p,                   /* Virtual table handle */
+  sqlite3_int64 iLevel,           /* Value for "level" field (absolute level) */
+  int iIdx,                       /* Value for "idx" field */
+  sqlite3_int64 iStartBlock,      /* Value for "start_block" field */
+  sqlite3_int64 iLeafEndBlock,    /* Value for "leaves_end_block" field */
+  sqlite3_int64 iEndBlock,        /* Value for "end_block" field */
+  sqlite3_int64 nLeafData,        /* Bytes of leaf data in segment */
+  char *zRoot,                    /* Blob value for "root" field */
+  int nRoot                       /* Number of bytes in buffer zRoot */
+){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_INSERT_SEGDIR, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iLevel);
+    sqlite3_bind_int(pStmt, 2, iIdx);
+    sqlite3_bind_int64(pStmt, 3, iStartBlock);
+    sqlite3_bind_int64(pStmt, 4, iLeafEndBlock);
+    if( nLeafData==0 ){
+      sqlite3_bind_int64(pStmt, 5, iEndBlock);
+    }else{
+      char *zEnd = sqlite3_mprintf("%lld %lld", iEndBlock, nLeafData);
+      if( !zEnd ) return SQLITE_NOMEM;
+      sqlite3_bind_text(pStmt, 5, zEnd, -1, sqlite3_free);
+    }
+    sqlite3_bind_blob(pStmt, 6, zRoot, nRoot, SQLITE_STATIC);
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+    sqlite3_bind_null(pStmt, 6);
+  }
+  return rc;
+}
+
+/*
+** Return the size of the common prefix (if any) shared by zPrev and
+** zNext, in bytes. For example,
+**
+**   fts3PrefixCompress("abc", 3, "abcdef", 6)   // returns 3
+**   fts3PrefixCompress("abX", 3, "abcdef", 6)   // returns 2
+**   fts3PrefixCompress("abX", 3, "Xbcdef", 6)   // returns 0
+*/
+static int fts3PrefixCompress(
+  const char *zPrev,              /* Buffer containing previous term */
+  int nPrev,                      /* Size of buffer zPrev in bytes */
+  const char *zNext,              /* Buffer containing next term */
+  int nNext                       /* Size of buffer zNext in bytes */
+){
+  int n;
+  for(n=0; n<nPrev && n<nNext && zPrev[n]==zNext[n]; n++);
+  assert_fts3_nc( n<nNext );
+  return n;
+}
+
+/*
+** Add term zTerm to the SegmentNode. It is guaranteed that zTerm is larger
+** (according to memcmp) than the previous term.
+*/
+static int fts3NodeAddTerm(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentNode **ppTree,           /* IN/OUT: SegmentNode handle */
+  int isCopyTerm,                 /* True if zTerm/nTerm is transient */
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm                       /* Size of term in bytes */
+){
+  SegmentNode *pTree = *ppTree;
+  int rc;
+  SegmentNode *pNew;
+
+  /* First try to append the term to the current node. Return early if
+  ** this is possible.
+  */
+  if( pTree ){
+    int nData = pTree->nData;     /* Current size of node in bytes */
+    int nReq = nData;             /* Required space after adding zTerm */
+    int nPrefix;                  /* Number of bytes of prefix compression */
+    int nSuffix;                  /* Suffix length */
+
+    nPrefix = fts3PrefixCompress(pTree->zTerm, pTree->nTerm, zTerm, nTerm);
+    nSuffix = nTerm-nPrefix;
+
+    /* If nSuffix is zero or less, then zTerm/nTerm must be a prefix of
+    ** pWriter->zTerm/pWriter->nTerm. i.e. must be equal to or less than when
+    ** compared with BINARY collation. This indicates corruption.  */
+    if( nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+
+    nReq += sqlite3Fts3VarintLen(nPrefix)+sqlite3Fts3VarintLen(nSuffix)+nSuffix;
+    if( nReq<=p->nNodeSize || !pTree->zTerm ){
+
+      if( nReq>p->nNodeSize ){
+        /* An unusual case: this is the first term to be added to the node
+        ** and the static node buffer (p->nNodeSize bytes) is not large
+        ** enough. Use a separately malloced buffer instead This wastes
+        ** p->nNodeSize bytes, but since this scenario only comes about when
+        ** the database contain two terms that share a prefix of almost 2KB,
+        ** this is not expected to be a serious problem.
+        */
+        assert( pTree->aData==(char *)&pTree[1] );
+        pTree->aData = (char *)sqlite3_malloc64(nReq);
+        if( !pTree->aData ){
+          return SQLITE_NOMEM;
+        }
+      }
+
+      if( pTree->zTerm ){
+        /* There is no prefix-length field for first term in a node */
+        nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nPrefix);
+      }
+
+      nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nSuffix);
+      memcpy(&pTree->aData[nData], &zTerm[nPrefix], nSuffix);
+      pTree->nData = nData + nSuffix;
+      pTree->nEntry++;
+
+      if( isCopyTerm ){
+        if( pTree->nMalloc<nTerm ){
+          char *zNew = sqlite3_realloc64(pTree->zMalloc, (i64)nTerm*2);
+          if( !zNew ){
+            return SQLITE_NOMEM;
+          }
+          pTree->nMalloc = nTerm*2;
+          pTree->zMalloc = zNew;
+        }
+        pTree->zTerm = pTree->zMalloc;
+        memcpy(pTree->zTerm, zTerm, nTerm);
+        pTree->nTerm = nTerm;
+      }else{
+        pTree->zTerm = (char *)zTerm;
+        pTree->nTerm = nTerm;
+      }
+      return SQLITE_OK;
+    }
+  }
+
+  /* If control flows to here, it was not possible to append zTerm to the
+  ** current node. Create a new node (a right-sibling of the current node).
+  ** If this is the first node in the tree, the term is added to it.
+  **
+  ** Otherwise, the term is not added to the new node, it is left empty for
+  ** now. Instead, the term is inserted into the parent of pTree. If pTree
+  ** has no parent, one is created here.
+  */
+  pNew = (SegmentNode *)sqlite3_malloc64(sizeof(SegmentNode) + p->nNodeSize);
+  if( !pNew ){
+    return SQLITE_NOMEM;
+  }
+  memset(pNew, 0, sizeof(SegmentNode));
+  pNew->nData = 1 + FTS3_VARINT_MAX;
+  pNew->aData = (char *)&pNew[1];
+
+  if( pTree ){
+    SegmentNode *pParent = pTree->pParent;
+    rc = fts3NodeAddTerm(p, &pParent, isCopyTerm, zTerm, nTerm);
+    if( pTree->pParent==0 ){
+      pTree->pParent = pParent;
+    }
+    pTree->pRight = pNew;
+    pNew->pLeftmost = pTree->pLeftmost;
+    pNew->pParent = pParent;
+    pNew->zMalloc = pTree->zMalloc;
+    pNew->nMalloc = pTree->nMalloc;
+    pTree->zMalloc = 0;
+  }else{
+    pNew->pLeftmost = pNew;
+    rc = fts3NodeAddTerm(p, &pNew, isCopyTerm, zTerm, nTerm);
+  }
+
+  *ppTree = pNew;
+  return rc;
+}
+
+/*
+** Helper function for fts3NodeWrite().
+*/
+static int fts3TreeFinishNode(
+  SegmentNode *pTree,
+  int iHeight,
+  sqlite3_int64 iLeftChild
+){
+  int nStart;
+  assert( iHeight>=1 && iHeight<128 );
+  nStart = FTS3_VARINT_MAX - sqlite3Fts3VarintLen(iLeftChild);
+  pTree->aData[nStart] = (char)iHeight;
+  sqlite3Fts3PutVarint(&pTree->aData[nStart+1], iLeftChild);
+  return nStart;
+}
+
+/*
+** Write the buffer for the segment node pTree and all of its peers to the
+** database. Then call this function recursively to write the parent of
+** pTree and its peers to the database.
+**
+** Except, if pTree is a root node, do not write it to the database. Instead,
+** set output variables *paRoot and *pnRoot to contain the root node.
+**
+** If successful, SQLITE_OK is returned and output variable *piLast is
+** set to the largest blockid written to the database (or zero if no
+** blocks were written to the db). Otherwise, an SQLite error code is
+** returned.
+*/
+static int fts3NodeWrite(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentNode *pTree,             /* SegmentNode handle */
+  int iHeight,                    /* Height of this node in tree */
+  sqlite3_int64 iLeaf,            /* Block id of first leaf node */
+  sqlite3_int64 iFree,            /* Block id of next free slot in %_segments */
+  sqlite3_int64 *piLast,          /* OUT: Block id of last entry written */
+  char **paRoot,                  /* OUT: Data for root node */
+  int *pnRoot                     /* OUT: Size of root node in bytes */
+){
+  int rc = SQLITE_OK;
+
+  if( !pTree->pParent ){
+    /* Root node of the tree. */
+    int nStart = fts3TreeFinishNode(pTree, iHeight, iLeaf);
+    *piLast = iFree-1;
+    *pnRoot = pTree->nData - nStart;
+    *paRoot = &pTree->aData[nStart];
+  }else{
+    SegmentNode *pIter;
+    sqlite3_int64 iNextFree = iFree;
+    sqlite3_int64 iNextLeaf = iLeaf;
+    for(pIter=pTree->pLeftmost; pIter && rc==SQLITE_OK; pIter=pIter->pRight){
+      int nStart = fts3TreeFinishNode(pIter, iHeight, iNextLeaf);
+      int nWrite = pIter->nData - nStart;
+
+      rc = fts3WriteSegment(p, iNextFree, &pIter->aData[nStart], nWrite);
+      iNextFree++;
+      iNextLeaf += (pIter->nEntry+1);
+    }
+    if( rc==SQLITE_OK ){
+      assert( iNextLeaf==iFree );
+      rc = fts3NodeWrite(
+          p, pTree->pParent, iHeight+1, iFree, iNextFree, piLast, paRoot, pnRoot
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Free all memory allocations associated with the tree pTree.
+*/
+static void fts3NodeFree(SegmentNode *pTree){
+  if( pTree ){
+    SegmentNode *p = pTree->pLeftmost;
+    fts3NodeFree(p->pParent);
+    while( p ){
+      SegmentNode *pRight = p->pRight;
+      if( p->aData!=(char *)&p[1] ){
+        sqlite3_free(p->aData);
+      }
+      assert( pRight==0 || p->zMalloc==0 );
+      sqlite3_free(p->zMalloc);
+      sqlite3_free(p);
+      p = pRight;
+    }
+  }
+}
+
+/*
+** Add a term to the segment being constructed by the SegmentWriter object
+** *ppWriter. When adding the first term to a segment, *ppWriter should
+** be passed NULL. This function will allocate a new SegmentWriter object
+** and return it via the input/output variable *ppWriter in this case.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+*/
+static int fts3SegWriterAdd(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentWriter **ppWriter,       /* IN/OUT: SegmentWriter handle */
+  int isCopyTerm,                 /* True if buffer zTerm must be copied */
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm,                      /* Size of term in bytes */
+  const char *aDoclist,           /* Pointer to buffer containing doclist */
+  int nDoclist                    /* Size of doclist in bytes */
+){
+  int nPrefix;                    /* Size of term prefix in bytes */
+  int nSuffix;                    /* Size of term suffix in bytes */
+  i64 nReq;                       /* Number of bytes required on leaf page */
+  int nData;
+  SegmentWriter *pWriter = *ppWriter;
+
+  if( !pWriter ){
+    int rc;
+    sqlite3_stmt *pStmt;
+
+    /* Allocate the SegmentWriter structure */
+    pWriter = (SegmentWriter *)sqlite3_malloc64(sizeof(SegmentWriter));
+    if( !pWriter ) return SQLITE_NOMEM;
+    memset(pWriter, 0, sizeof(SegmentWriter));
+    *ppWriter = pWriter;
+
+    /* Allocate a buffer in which to accumulate data */
+    pWriter->aData = (char *)sqlite3_malloc64(p->nNodeSize);
+    if( !pWriter->aData ) return SQLITE_NOMEM;
+    pWriter->nSize = p->nNodeSize;
+
+    /* Find the next free blockid in the %_segments table */
+    rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pStmt, 0);
+    if( rc!=SQLITE_OK ) return rc;
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      pWriter->iFree = sqlite3_column_int64(pStmt, 0);
+      pWriter->iFirst = pWriter->iFree;
+    }
+    rc = sqlite3_reset(pStmt);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  nData = pWriter->nData;
+
+  nPrefix = fts3PrefixCompress(pWriter->zTerm, pWriter->nTerm, zTerm, nTerm);
+  nSuffix = nTerm-nPrefix;
+
+  /* If nSuffix is zero or less, then zTerm/nTerm must be a prefix of
+  ** pWriter->zTerm/pWriter->nTerm. i.e. must be equal to or less than when
+  ** compared with BINARY collation. This indicates corruption.  */
+  if( nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+
+  /* Figure out how many bytes are required by this new entry */
+  nReq = sqlite3Fts3VarintLen(nPrefix) +    /* varint containing prefix size */
+    sqlite3Fts3VarintLen(nSuffix) +         /* varint containing suffix size */
+    nSuffix +                               /* Term suffix */
+    sqlite3Fts3VarintLen(nDoclist) +        /* Size of doclist */
+    nDoclist;                               /* Doclist data */
+
+  if( nData>0 && nData+nReq>p->nNodeSize ){
+    int rc;
+
+    /* The current leaf node is full. Write it out to the database. */
+    if( pWriter->iFree==LARGEST_INT64 ) return FTS_CORRUPT_VTAB;
+    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, nData);
+    if( rc!=SQLITE_OK ) return rc;
+    p->nLeafAdd++;
+
+    /* Add the current term to the interior node tree. The term added to
+    ** the interior tree must:
+    **
+    **   a) be greater than the largest term on the leaf node just written
+    **      to the database (still available in pWriter->zTerm), and
+    **
+    **   b) be less than or equal to the term about to be added to the new
+    **      leaf node (zTerm/nTerm).
+    **
+    ** In other words, it must be the prefix of zTerm 1 byte longer than
+    ** the common prefix (if any) of zTerm and pWriter->zTerm.
+    */
+    assert( nPrefix<nTerm );
+    rc = fts3NodeAddTerm(p, &pWriter->pTree, isCopyTerm, zTerm, nPrefix+1);
+    if( rc!=SQLITE_OK ) return rc;
+
+    nData = 0;
+    pWriter->nTerm = 0;
+
+    nPrefix = 0;
+    nSuffix = nTerm;
+    nReq = 1 +                              /* varint containing prefix size */
+      sqlite3Fts3VarintLen(nTerm) +         /* varint containing suffix size */
+      nTerm +                               /* Term suffix */
+      sqlite3Fts3VarintLen(nDoclist) +      /* Size of doclist */
+      nDoclist;                             /* Doclist data */
+  }
+
+  /* Increase the total number of bytes written to account for the new entry. */
+  pWriter->nLeafData += nReq;
+
+  /* If the buffer currently allocated is too small for this entry, realloc
+  ** the buffer to make it large enough.
+  */
+  if( nReq>pWriter->nSize ){
+    char *aNew = sqlite3_realloc64(pWriter->aData, nReq);
+    if( !aNew ) return SQLITE_NOMEM;
+    pWriter->aData = aNew;
+    pWriter->nSize = nReq;
+  }
+  assert( nData+nReq<=pWriter->nSize );
+
+  /* Append the prefix-compressed term and doclist to the buffer. */
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nPrefix);
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nSuffix);
+  assert( nSuffix>0 );
+  memcpy(&pWriter->aData[nData], &zTerm[nPrefix], nSuffix);
+  nData += nSuffix;
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nDoclist);
+  assert( nDoclist>0 );
+  memcpy(&pWriter->aData[nData], aDoclist, nDoclist);
+  pWriter->nData = nData + nDoclist;
+
+  /* Save the current term so that it can be used to prefix-compress the next.
+  ** If the isCopyTerm parameter is true, then the buffer pointed to by
+  ** zTerm is transient, so take a copy of the term data. Otherwise, just
+  ** store a copy of the pointer.
+  */
+  if( isCopyTerm ){
+    if( nTerm>pWriter->nMalloc ){
+      char *zNew = sqlite3_realloc64(pWriter->zMalloc, (i64)nTerm*2);
+      if( !zNew ){
+        return SQLITE_NOMEM;
+      }
+      pWriter->nMalloc = nTerm*2;
+      pWriter->zMalloc = zNew;
+      pWriter->zTerm = zNew;
+    }
+    assert( pWriter->zTerm==pWriter->zMalloc );
+    assert( nTerm>0 );
+    memcpy(pWriter->zTerm, zTerm, nTerm);
+  }else{
+    pWriter->zTerm = (char *)zTerm;
+  }
+  pWriter->nTerm = nTerm;
+
+  return SQLITE_OK;
+}
+
+/*
+** Flush all data associated with the SegmentWriter object pWriter to the
+** database. This function must be called after all terms have been added
+** to the segment using fts3SegWriterAdd(). If successful, SQLITE_OK is
+** returned. Otherwise, an SQLite error code.
+*/
+static int fts3SegWriterFlush(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentWriter *pWriter,         /* SegmentWriter to flush to the db */
+  sqlite3_int64 iLevel,           /* Value for 'level' column of %_segdir */
+  int iIdx                        /* Value for 'idx' column of %_segdir */
+){
+  int rc;                         /* Return code */
+  if( pWriter->pTree ){
+    sqlite3_int64 iLast = 0;      /* Largest block id written to database */
+    sqlite3_int64 iLastLeaf;      /* Largest leaf block id written to db */
+    char *zRoot = NULL;           /* Pointer to buffer containing root node */
+    int nRoot = 0;                /* Size of buffer zRoot */
+
+    iLastLeaf = pWriter->iFree;
+    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, pWriter->nData);
+    if( rc==SQLITE_OK ){
+      rc = fts3NodeWrite(p, pWriter->pTree, 1,
+          pWriter->iFirst, pWriter->iFree, &iLast, &zRoot, &nRoot);
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3WriteSegdir(p, iLevel, iIdx,
+          pWriter->iFirst, iLastLeaf, iLast, pWriter->nLeafData, zRoot, nRoot);
+    }
+  }else{
+    /* The entire tree fits on the root node. Write it to the segdir table. */
+    rc = fts3WriteSegdir(p, iLevel, iIdx,
+        0, 0, 0, pWriter->nLeafData, pWriter->aData, pWriter->nData);
+  }
+  p->nLeafAdd++;
+  return rc;
+}
+
+/*
+** Release all memory held by the SegmentWriter object passed as the
+** first argument.
+*/
+static void fts3SegWriterFree(SegmentWriter *pWriter){
+  if( pWriter ){
+    sqlite3_free(pWriter->aData);
+    sqlite3_free(pWriter->zMalloc);
+    fts3NodeFree(pWriter->pTree);
+    sqlite3_free(pWriter);
+  }
+}
+
+/*
+** The first value in the apVal[] array is assumed to contain an integer.
+** This function tests if there exist any documents with docid values that
+** are different from that integer. i.e. if deleting the document with docid
+** pRowid would mean the FTS3 table were empty.
+**
+** If successful, *pisEmpty is set to true if the table is empty except for
+** document pRowid, or false otherwise, and SQLITE_OK is returned. If an
+** error occurs, an SQLite error code is returned.
+*/
+static int fts3IsEmpty(Fts3Table *p, sqlite3_value *pRowid, int *pisEmpty){
+  sqlite3_stmt *pStmt;
+  int rc;
+  if( p->zContentTbl ){
+    /* If using the content=xxx option, assume the table is never empty */
+    *pisEmpty = 0;
+    rc = SQLITE_OK;
+  }else{
+    rc = fts3SqlStmt(p, SQL_IS_EMPTY, &pStmt, &pRowid);
+    if( rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        *pisEmpty = sqlite3_column_int(pStmt, 0);
+      }
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+  return rc;
+}
+
+/*
+** Set *pnMax to the largest segment level in the database for the index
+** iIndex.
+**
+** Segment levels are stored in the 'level' column of the %_segdir table.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if not.
+*/
+static int fts3SegmentMaxLevel(
+  Fts3Table *p,
+  int iLangid,
+  int iIndex,
+  sqlite3_int64 *pnMax
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  /* Set pStmt to the compiled version of:
+  **
+  **   SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?
+  **
+  ** (1024 is actually the value of macro FTS3_SEGDIR_PREFIXLEVEL_STR).
+  */
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR_MAX_LEVEL, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
+  sqlite3_bind_int64(pStmt, 2,
+      getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
+  );
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    *pnMax = sqlite3_column_int64(pStmt, 0);
+  }
+  return sqlite3_reset(pStmt);
+}
+
+/*
+** iAbsLevel is an absolute level that may be assumed to exist within
+** the database. This function checks if it is the largest level number
+** within its index. Assuming no error occurs, *pbMax is set to 1 if
+** iAbsLevel is indeed the largest level, or 0 otherwise, and SQLITE_OK
+** is returned. If an error occurs, an error code is returned and the
+** final value of *pbMax is undefined.
+*/
+static int fts3SegmentIsMaxLevel(Fts3Table *p, i64 iAbsLevel, int *pbMax){
+
+  /* Set pStmt to the compiled version of:
+  **
+  **   SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?
+  **
+  ** (1024 is actually the value of macro FTS3_SEGDIR_PREFIXLEVEL_STR).
+  */
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR_MAX_LEVEL, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  sqlite3_bind_int64(pStmt, 1, iAbsLevel+1);
+  sqlite3_bind_int64(pStmt, 2,
+      (((u64)iAbsLevel/FTS3_SEGDIR_MAXLEVEL)+1) * FTS3_SEGDIR_MAXLEVEL
+  );
+
+  *pbMax = 0;
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    *pbMax = sqlite3_column_type(pStmt, 0)==SQLITE_NULL;
+  }
+  return sqlite3_reset(pStmt);
+}
+
+/*
+** Delete all entries in the %_segments table associated with the segment
+** opened with seg-reader pSeg. This function does not affect the contents
+** of the %_segdir table.
+*/
+static int fts3DeleteSegment(
+  Fts3Table *p,                   /* FTS table handle */
+  Fts3SegReader *pSeg             /* Segment to delete */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  if( pSeg->iStartBlock ){
+    sqlite3_stmt *pDelete;        /* SQL statement to delete rows */
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDelete, 1, pSeg->iStartBlock);
+      sqlite3_bind_int64(pDelete, 2, pSeg->iEndBlock);
+      sqlite3_step(pDelete);
+      rc = sqlite3_reset(pDelete);
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is used after merging multiple segments into a single large
+** segment to delete the old, now redundant, segment b-trees. Specifically,
+** it:
+**
+**   1) Deletes all %_segments entries for the segments associated with
+**      each of the SegReader objects in the array passed as the third
+**      argument, and
+**
+**   2) deletes all %_segdir entries with level iLevel, or all %_segdir
+**      entries regardless of level if (iLevel<0).
+**
+** SQLITE_OK is returned if successful, otherwise an SQLite error code.
+*/
+static int fts3DeleteSegdir(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index for p->aIndex */
+  int iLevel,                     /* Level of %_segdir entries to delete */
+  Fts3SegReader **apSegment,      /* Array of SegReader objects */
+  int nReader                     /* Size of array apSegment */
+){
+  int rc = SQLITE_OK;             /* Return Code */
+  int i;                          /* Iterator variable */
+  sqlite3_stmt *pDelete = 0;      /* SQL statement to delete rows */
+
+  for(i=0; rc==SQLITE_OK && i<nReader; i++){
+    rc = fts3DeleteSegment(p, apSegment[i]);
+  }
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  assert( iLevel>=0 || iLevel==FTS3_SEGCURSOR_ALL );
+  if( iLevel==FTS3_SEGCURSOR_ALL ){
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_RANGE, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDelete, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
+      sqlite3_bind_int64(pDelete, 2,
+          getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
+      );
+    }
+  }else{
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_LEVEL, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(
+          pDelete, 1, getAbsoluteLevel(p, iLangid, iIndex, iLevel)
+      );
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sqlite3_step(pDelete);
+    rc = sqlite3_reset(pDelete);
+  }
+
+  return rc;
+}
+
+/*
+** When this function is called, buffer *ppList (size *pnList bytes) contains
+** a position list that may (or may not) feature multiple columns. This
+** function adjusts the pointer *ppList and the length *pnList so that they
+** identify the subset of the position list that corresponds to column iCol.
+**
+** If there are no entries in the input position list for column iCol, then
+** *pnList is set to zero before returning.
+**
+** If parameter bZero is non-zero, then any part of the input list following
+** the end of the output list is zeroed before returning.
+*/
+static void fts3ColumnFilter(
+  int iCol,                       /* Column to filter on */
+  int bZero,                      /* Zero out anything following *ppList */
+  char **ppList,                  /* IN/OUT: Pointer to position list */
+  int *pnList                     /* IN/OUT: Size of buffer *ppList in bytes */
+){
+  char *pList = *ppList;
+  int nList = *pnList;
+  char *pEnd = &pList[nList];
+  int iCurrent = 0;
+  char *p = pList;
+
+  assert( iCol>=0 );
+  while( 1 ){
+    char c = 0;
+    while( p<pEnd && (c | *p)&0xFE ) c = *p++ & 0x80;
+
+    if( iCol==iCurrent ){
+      nList = (int)(p - pList);
+      break;
+    }
+
+    nList -= (int)(p - pList);
+    pList = p;
+    if( nList<=0 ){
+      break;
+    }
+    p = &pList[1];
+    p += fts3GetVarint32(p, &iCurrent);
+  }
+
+  if( bZero && (pEnd - &pList[nList])>0){
+    memset(&pList[nList], 0, pEnd - &pList[nList]);
+  }
+  *ppList = pList;
+  *pnList = nList;
+}
+
+/*
+** Cache data in the Fts3MultiSegReader.aBuffer[] buffer (overwriting any
+** existing data). Grow the buffer if required.
+**
+** If successful, return SQLITE_OK. Otherwise, if an OOM error is encountered
+** trying to resize the buffer, return SQLITE_NOMEM.
+*/
+static int fts3MsrBufferData(
+  Fts3MultiSegReader *pMsr,       /* Multi-segment-reader handle */
+  char *pList,
+  i64 nList
+){
+  if( (nList+FTS3_NODE_PADDING)>pMsr->nBuffer ){
+    char *pNew;
+    int nNew = nList*2 + FTS3_NODE_PADDING;
+    pNew = (char *)sqlite3_realloc64(pMsr->aBuffer, nNew);
+    if( !pNew ) return SQLITE_NOMEM;
+    pMsr->aBuffer = pNew;
+    pMsr->nBuffer = nNew;
+  }
+
+  assert( nList>0 );
+  memcpy(pMsr->aBuffer, pList, nList);
+  memset(&pMsr->aBuffer[nList], 0, FTS3_NODE_PADDING);
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrNext(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pMsr,       /* Multi-segment-reader handle */
+  sqlite3_int64 *piDocid,         /* OUT: Docid value */
+  char **paPoslist,               /* OUT: Pointer to position list */
+  int *pnPoslist                  /* OUT: Size of position list in bytes */
+){
+  int nMerge = pMsr->nAdvance;
+  Fts3SegReader **apSegment = pMsr->apSegment;
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
+    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
+  );
+
+  if( nMerge==0 ){
+    *paPoslist = 0;
+    return SQLITE_OK;
+  }
+
+  while( 1 ){
+    Fts3SegReader *pSeg;
+    pSeg = pMsr->apSegment[0];
+
+    if( pSeg->pOffsetList==0 ){
+      *paPoslist = 0;
+      break;
+    }else{
+      int rc;
+      char *pList;
+      int nList;
+      int j;
+      sqlite3_int64 iDocid = apSegment[0]->iDocid;
+
+      rc = fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
+      j = 1;
+      while( rc==SQLITE_OK
+        && j<nMerge
+        && apSegment[j]->pOffsetList
+        && apSegment[j]->iDocid==iDocid
+      ){
+        rc = fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
+        j++;
+      }
+      if( rc!=SQLITE_OK ) return rc;
+      fts3SegReaderSort(pMsr->apSegment, nMerge, j, xCmp);
+
+      if( nList>0 && fts3SegReaderIsPending(apSegment[0]) ){
+        rc = fts3MsrBufferData(pMsr, pList, (i64)nList+1);
+        if( rc!=SQLITE_OK ) return rc;
+        assert( (pMsr->aBuffer[nList] & 0xFE)==0x00 );
+        pList = pMsr->aBuffer;
+      }
+
+      if( pMsr->iColFilter>=0 ){
+        fts3ColumnFilter(pMsr->iColFilter, 1, &pList, &nList);
+      }
+
+      if( nList>0 ){
+        *paPoslist = pList;
+        *piDocid = iDocid;
+        *pnPoslist = nList;
+        break;
+      }
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+static int fts3SegReaderStart(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr,       /* Cursor object */
+  const char *zTerm,              /* Term searched for (or NULL) */
+  int nTerm                       /* Length of zTerm in bytes */
+){
+  int i;
+  int nSeg = pCsr->nSegment;
+
+  /* If the Fts3SegFilter defines a specific term (or term prefix) to search
+  ** for, then advance each segment iterator until it points to a term of
+  ** equal or greater value than the specified term. This prevents many
+  ** unnecessary merge/sort operations for the case where single segment
+  ** b-tree leaf nodes contain more than one term.
+  */
+  for(i=0; pCsr->bRestart==0 && i<pCsr->nSegment; i++){
+    int res = 0;
+    Fts3SegReader *pSeg = pCsr->apSegment[i];
+    do {
+      int rc = fts3SegReaderNext(p, pSeg, 0);
+      if( rc!=SQLITE_OK ) return rc;
+    }while( zTerm && (res = fts3SegReaderTermCmp(pSeg, zTerm, nTerm))<0 );
+
+    if( pSeg->bLookup && res!=0 ){
+      fts3SegReaderSetEof(pSeg);
+    }
+  }
+  fts3SegReaderSort(pCsr->apSegment, nSeg, nSeg, fts3SegReaderCmp);
+
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStart(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr,       /* Cursor object */
+  Fts3SegFilter *pFilter          /* Restrictions on range of iteration */
+){
+  pCsr->pFilter = pFilter;
+  return fts3SegReaderStart(p, pCsr, pFilter->zTerm, pFilter->nTerm);
+}
+
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrStart(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr,       /* Cursor object */
+  int iCol,                       /* Column to match on. */
+  const char *zTerm,              /* Term to iterate through a doclist for */
+  int nTerm                       /* Number of bytes in zTerm */
+){
+  int i;
+  int rc;
+  int nSegment = pCsr->nSegment;
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
+    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
+  );
+
+  assert( pCsr->pFilter==0 );
+  assert( zTerm && nTerm>0 );
+
+  /* Advance each segment iterator until it points to the term zTerm/nTerm. */
+  rc = fts3SegReaderStart(p, pCsr, zTerm, nTerm);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Determine how many of the segments actually point to zTerm/nTerm. */
+  for(i=0; i<nSegment; i++){
+    Fts3SegReader *pSeg = pCsr->apSegment[i];
+    if( !pSeg->aNode || fts3SegReaderTermCmp(pSeg, zTerm, nTerm) ){
+      break;
+    }
+  }
+  pCsr->nAdvance = i;
+
+  /* Advance each of the segments to point to the first docid. */
+  for(i=0; i<pCsr->nAdvance; i++){
+    rc = fts3SegReaderFirstDocid(p, pCsr->apSegment[i]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  fts3SegReaderSort(pCsr->apSegment, i, i, xCmp);
+
+  assert( iCol<0 || iCol<p->nColumn );
+  pCsr->iColFilter = iCol;
+
+  return SQLITE_OK;
+}
+
+/*
+** This function is called on a MultiSegReader that has been started using
+** sqlite3Fts3MsrIncrStart(). One or more calls to MsrIncrNext() may also
+** have been made. Calling this function puts the MultiSegReader in such
+** a state that if the next two calls are:
+**
+**   sqlite3Fts3SegReaderStart()
+**   sqlite3Fts3SegReaderStep()
+**
+** then the entire doclist for the term is available in
+** MultiSegReader.aDoclist/nDoclist.
+*/
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr){
+  int i;                          /* Used to iterate through segment-readers */
+
+  assert( pCsr->zTerm==0 );
+  assert( pCsr->nTerm==0 );
+  assert( pCsr->aDoclist==0 );
+  assert( pCsr->nDoclist==0 );
+
+  pCsr->nAdvance = 0;
+  pCsr->bRestart = 1;
+  for(i=0; i<pCsr->nSegment; i++){
+    pCsr->apSegment[i]->pOffsetList = 0;
+    pCsr->apSegment[i]->nOffsetList = 0;
+    pCsr->apSegment[i]->iDocid = 0;
+  }
+
+  return SQLITE_OK;
+}
+
+static int fts3GrowSegReaderBuffer(Fts3MultiSegReader *pCsr, i64 nReq){
+  if( nReq>pCsr->nBuffer ){
+    char *aNew;
+    pCsr->nBuffer = nReq*2;
+    aNew = sqlite3_realloc64(pCsr->aBuffer, pCsr->nBuffer);
+    if( !aNew ){
+      return SQLITE_NOMEM;
+    }
+    pCsr->aBuffer = aNew;
+  }
+  return SQLITE_OK;
+}
+
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStep(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr        /* Cursor object */
+){
+  int rc = SQLITE_OK;
+
+  int isIgnoreEmpty =  (pCsr->pFilter->flags & FTS3_SEGMENT_IGNORE_EMPTY);
+  int isRequirePos =   (pCsr->pFilter->flags & FTS3_SEGMENT_REQUIRE_POS);
+  int isColFilter =    (pCsr->pFilter->flags & FTS3_SEGMENT_COLUMN_FILTER);
+  int isPrefix =       (pCsr->pFilter->flags & FTS3_SEGMENT_PREFIX);
+  int isScan =         (pCsr->pFilter->flags & FTS3_SEGMENT_SCAN);
+  int isFirst =        (pCsr->pFilter->flags & FTS3_SEGMENT_FIRST);
+
+  Fts3SegReader **apSegment = pCsr->apSegment;
+  int nSegment = pCsr->nSegment;
+  Fts3SegFilter *pFilter = pCsr->pFilter;
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
+    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
+  );
+
+  if( pCsr->nSegment==0 ) return SQLITE_OK;
+
+  do {
+    int nMerge;
+    int i;
+
+    /* Advance the first pCsr->nAdvance entries in the apSegment[] array
+    ** forward. Then sort the list in order of current term again.
+    */
+    for(i=0; i<pCsr->nAdvance; i++){
+      Fts3SegReader *pSeg = apSegment[i];
+      if( pSeg->bLookup ){
+        fts3SegReaderSetEof(pSeg);
+      }else{
+        rc = fts3SegReaderNext(p, pSeg, 0);
+      }
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    fts3SegReaderSort(apSegment, nSegment, pCsr->nAdvance, fts3SegReaderCmp);
+    pCsr->nAdvance = 0;
+
+    /* If all the seg-readers are at EOF, we're finished. return SQLITE_OK. */
+    assert( rc==SQLITE_OK );
+    if( apSegment[0]->aNode==0 ) break;
+
+    pCsr->nTerm = apSegment[0]->nTerm;
+    pCsr->zTerm = apSegment[0]->zTerm;
+
+    /* If this is a prefix-search, and if the term that apSegment[0] points
+    ** to does not share a suffix with pFilter->zTerm/nTerm, then all
+    ** required callbacks have been made. In this case exit early.
+    **
+    ** Similarly, if this is a search for an exact match, and the first term
+    ** of segment apSegment[0] is not a match, exit early.
+    */
+    if( pFilter->zTerm && !isScan ){
+      if( pCsr->nTerm<pFilter->nTerm
+       || (!isPrefix && pCsr->nTerm>pFilter->nTerm)
+       || memcmp(pCsr->zTerm, pFilter->zTerm, pFilter->nTerm)
+      ){
+        break;
+      }
+    }
+
+    nMerge = 1;
+    while( nMerge<nSegment
+        && apSegment[nMerge]->aNode
+        && apSegment[nMerge]->nTerm==pCsr->nTerm
+        && 0==memcmp(pCsr->zTerm, apSegment[nMerge]->zTerm, pCsr->nTerm)
+    ){
+      nMerge++;
+    }
+
+    assert( isIgnoreEmpty || (isRequirePos && !isColFilter) );
+    if( nMerge==1
+     && !isIgnoreEmpty
+     && !isFirst
+     && (p->bDescIdx==0 || fts3SegReaderIsPending(apSegment[0])==0)
+    ){
+      pCsr->nDoclist = apSegment[0]->nDoclist;
+      if( fts3SegReaderIsPending(apSegment[0]) ){
+        rc = fts3MsrBufferData(pCsr, apSegment[0]->aDoclist,
+                               (i64)pCsr->nDoclist);
+        pCsr->aDoclist = pCsr->aBuffer;
+      }else{
+        pCsr->aDoclist = apSegment[0]->aDoclist;
+      }
+      if( rc==SQLITE_OK ) rc = SQLITE_ROW;
+    }else{
+      int nDoclist = 0;           /* Size of doclist */
+      sqlite3_int64 iPrev = 0;    /* Previous docid stored in doclist */
+
+      /* The current term of the first nMerge entries in the array
+      ** of Fts3SegReader objects is the same. The doclists must be merged
+      ** and a single term returned with the merged doclist.
+      */
+      for(i=0; i<nMerge; i++){
+        fts3SegReaderFirstDocid(p, apSegment[i]);
+      }
+      fts3SegReaderSort(apSegment, nMerge, nMerge, xCmp);
+      while( apSegment[0]->pOffsetList ){
+        int j;                    /* Number of segments that share a docid */
+        char *pList = 0;
+        int nList = 0;
+        int nByte;
+        sqlite3_int64 iDocid = apSegment[0]->iDocid;
+        fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
+        j = 1;
+        while( j<nMerge
+            && apSegment[j]->pOffsetList
+            && apSegment[j]->iDocid==iDocid
+        ){
+          fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
+          j++;
+        }
+
+        if( isColFilter ){
+          fts3ColumnFilter(pFilter->iCol, 0, &pList, &nList);
+        }
+
+        if( !isIgnoreEmpty || nList>0 ){
+
+          /* Calculate the 'docid' delta value to write into the merged
+          ** doclist. */
+          sqlite3_int64 iDelta;
+          if( p->bDescIdx && nDoclist>0 ){
+            if( iPrev<=iDocid ) return FTS_CORRUPT_VTAB;
+            iDelta = (i64)((u64)iPrev - (u64)iDocid);
+          }else{
+            if( nDoclist>0 && iPrev>=iDocid ) return FTS_CORRUPT_VTAB;
+            iDelta = (i64)((u64)iDocid - (u64)iPrev);
+          }
+
+          nByte = sqlite3Fts3VarintLen(iDelta) + (isRequirePos?nList+1:0);
+
+          rc = fts3GrowSegReaderBuffer(pCsr,
+                                   (i64)nByte+nDoclist+FTS3_NODE_PADDING);
+          if( rc ) return rc;
+
+          if( isFirst ){
+            char *a = &pCsr->aBuffer[nDoclist];
+            int nWrite;
+
+            nWrite = sqlite3Fts3FirstFilter(iDelta, pList, nList, a);
+            if( nWrite ){
+              iPrev = iDocid;
+              nDoclist += nWrite;
+            }
+          }else{
+            nDoclist += sqlite3Fts3PutVarint(&pCsr->aBuffer[nDoclist], iDelta);
+            iPrev = iDocid;
+            if( isRequirePos ){
+              memcpy(&pCsr->aBuffer[nDoclist], pList, nList);
+              nDoclist += nList;
+              pCsr->aBuffer[nDoclist++] = '\0';
+            }
+          }
+        }
+
+        fts3SegReaderSort(apSegment, nMerge, j, xCmp);
+      }
+      if( nDoclist>0 ){
+        rc = fts3GrowSegReaderBuffer(pCsr, (i64)nDoclist+FTS3_NODE_PADDING);
+        if( rc ) return rc;
+        memset(&pCsr->aBuffer[nDoclist], 0, FTS3_NODE_PADDING);
+        pCsr->aDoclist = pCsr->aBuffer;
+        pCsr->nDoclist = nDoclist;
+        rc = SQLITE_ROW;
+      }
+    }
+    pCsr->nAdvance = nMerge;
+  }while( rc==SQLITE_OK );
+
+  return rc;
+}
+
+
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFinish(
+  Fts3MultiSegReader *pCsr       /* Cursor object */
+){
+  if( pCsr ){
+    int i;
+    for(i=0; i<pCsr->nSegment; i++){
+      sqlite3Fts3SegReaderFree(pCsr->apSegment[i]);
+    }
+    sqlite3_free(pCsr->apSegment);
+    sqlite3_free(pCsr->aBuffer);
+
+    pCsr->nSegment = 0;
+    pCsr->apSegment = 0;
+    pCsr->aBuffer = 0;
+  }
+}
+
+/*
+** Decode the "end_block" field, selected by column iCol of the SELECT
+** statement passed as the first argument.
+**
+** The "end_block" field may contain either an integer, or a text field
+** containing the text representation of two non-negative integers separated
+** by one or more space (0x20) characters. In the first case, set *piEndBlock
+** to the integer value and *pnByte to zero before returning. In the second,
+** set *piEndBlock to the first value and *pnByte to the second.
+*/
+static void fts3ReadEndBlockField(
+  sqlite3_stmt *pStmt,
+  int iCol,
+  i64 *piEndBlock,
+  i64 *pnByte
+){
+  const unsigned char *zText = sqlite3_column_text(pStmt, iCol);
+  if( zText ){
+    int i;
+    int iMul = 1;
+    u64 iVal = 0;
+    for(i=0; zText[i]>='0' && zText[i]<='9'; i++){
+      iVal = iVal*10 + (zText[i] - '0');
+    }
+    *piEndBlock = (i64)iVal;
+    while( zText[i]==' ' ) i++;
+    iVal = 0;
+    if( zText[i]=='-' ){
+      i++;
+      iMul = -1;
+    }
+    for(/* no-op */; zText[i]>='0' && zText[i]<='9'; i++){
+      iVal = iVal*10 + (zText[i] - '0');
+    }
+    *pnByte = ((i64)iVal * (i64)iMul);
+  }
+}
+
+
+/*
+** A segment of size nByte bytes has just been written to absolute level
+** iAbsLevel. Promote any segments that should be promoted as a result.
+*/
+static int fts3PromoteSegments(
+  Fts3Table *p,                   /* FTS table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level just updated */
+  sqlite3_int64 nByte             /* Size of new segment at iAbsLevel */
+){
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pRange;
+
+  rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_RANGE2, &pRange, 0);
+
+  if( rc==SQLITE_OK ){
+    int bOk = 0;
+    i64 iLast = (iAbsLevel/FTS3_SEGDIR_MAXLEVEL + 1) * FTS3_SEGDIR_MAXLEVEL - 1;
+    i64 nLimit = (nByte*3)/2;
+
+    /* Loop through all entries in the %_segdir table corresponding to
+    ** segments in this index on levels greater than iAbsLevel. If there is
+    ** at least one such segment, and it is possible to determine that all
+    ** such segments are smaller than nLimit bytes in size, they will be
+    ** promoted to level iAbsLevel.  */
+    sqlite3_bind_int64(pRange, 1, iAbsLevel+1);
+    sqlite3_bind_int64(pRange, 2, iLast);
+    while( SQLITE_ROW==sqlite3_step(pRange) ){
+      i64 nSize = 0, dummy;
+      fts3ReadEndBlockField(pRange, 2, &dummy, &nSize);
+      if( nSize<=0 || nSize>nLimit ){
+        /* If nSize==0, then the %_segdir.end_block field does not not
+        ** contain a size value. This happens if it was written by an
+        ** old version of FTS. In this case it is not possible to determine
+        ** the size of the segment, and so segment promotion does not
+        ** take place.  */
+        bOk = 0;
+        break;
+      }
+      bOk = 1;
+    }
+    rc = sqlite3_reset(pRange);
+
+    if( bOk ){
+      int iIdx = 0;
+      sqlite3_stmt *pUpdate1 = 0;
+      sqlite3_stmt *pUpdate2 = 0;
+
+      if( rc==SQLITE_OK ){
+        rc = fts3SqlStmt(p, SQL_UPDATE_LEVEL_IDX, &pUpdate1, 0);
+      }
+      if( rc==SQLITE_OK ){
+        rc = fts3SqlStmt(p, SQL_UPDATE_LEVEL, &pUpdate2, 0);
+      }
+
+      if( rc==SQLITE_OK ){
+
+        /* Loop through all %_segdir entries for segments in this index with
+        ** levels equal to or greater than iAbsLevel. As each entry is visited,
+        ** updated it to set (level = -1) and (idx = N), where N is 0 for the
+        ** oldest segment in the range, 1 for the next oldest, and so on.
+        **
+        ** In other words, move all segments being promoted to level -1,
+        ** setting the "idx" fields as appropriate to keep them in the same
+        ** order. The contents of level -1 (which is never used, except
+        ** transiently here), will be moved back to level iAbsLevel below.  */
+        sqlite3_bind_int64(pRange, 1, iAbsLevel);
+        while( SQLITE_ROW==sqlite3_step(pRange) ){
+          sqlite3_bind_int(pUpdate1, 1, iIdx++);
+          sqlite3_bind_int(pUpdate1, 2, sqlite3_column_int(pRange, 0));
+          sqlite3_bind_int(pUpdate1, 3, sqlite3_column_int(pRange, 1));
+          sqlite3_step(pUpdate1);
+          rc = sqlite3_reset(pUpdate1);
+          if( rc!=SQLITE_OK ){
+            sqlite3_reset(pRange);
+            break;
+          }
+        }
+      }
+      if( rc==SQLITE_OK ){
+        rc = sqlite3_reset(pRange);
+      }
+
+      /* Move level -1 to level iAbsLevel */
+      if( rc==SQLITE_OK ){
+        sqlite3_bind_int64(pUpdate2, 1, iAbsLevel);
+        sqlite3_step(pUpdate2);
+        rc = sqlite3_reset(pUpdate2);
+      }
+    }
+  }
+
+
+  return rc;
+}
+
+/*
+** Merge all level iLevel segments in the database into a single
+** iLevel+1 segment. Or, if iLevel<0, merge all segments into a
+** single segment with a level equal to the numerically largest level
+** currently present in the database.
+**
+** If this function is called with iLevel<0, but there is only one
+** segment in the database, SQLITE_DONE is returned immediately.
+** Otherwise, if successful, SQLITE_OK is returned. If an error occurs,
+** an SQLite error code is returned.
+*/
+static int fts3SegmentMerge(
+  Fts3Table *p,
+  int iLangid,                    /* Language id to merge */
+  int iIndex,                     /* Index in p->aIndex[] to merge */
+  int iLevel                      /* Level to merge */
+){
+  int rc;                         /* Return code */
+  int iIdx = 0;                   /* Index of new segment */
+  sqlite3_int64 iNewLevel = 0;    /* Level/index to create new segment at */
+  SegmentWriter *pWriter = 0;     /* Used to write the new, merged, segment */
+  Fts3SegFilter filter;           /* Segment term filter condition */
+  Fts3MultiSegReader csr;         /* Cursor to iterate through level(s) */
+  int bIgnoreEmpty = 0;           /* True to ignore empty segments */
+  i64 iMaxLevel = 0;              /* Max level number for this index/langid */
+
+  assert( iLevel==FTS3_SEGCURSOR_ALL
+       || iLevel==FTS3_SEGCURSOR_PENDING
+       || iLevel>=0
+  );
+  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  rc = sqlite3Fts3SegReaderCursor(p, iLangid, iIndex, iLevel, 0, 0, 1, 0, &csr);
+  if( rc!=SQLITE_OK || csr.nSegment==0 ) goto finished;
+
+  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
+    rc = fts3SegmentMaxLevel(p, iLangid, iIndex, &iMaxLevel);
+    if( rc!=SQLITE_OK ) goto finished;
+  }
+
+  if( iLevel==FTS3_SEGCURSOR_ALL ){
+    /* This call is to merge all segments in the database to a single
+    ** segment. The level of the new segment is equal to the numerically
+    ** greatest segment level currently present in the database for this
+    ** index. The idx of the new segment is always 0.  */
+    if( csr.nSegment==1 && 0==fts3SegReaderIsPending(csr.apSegment[0]) ){
+      rc = SQLITE_DONE;
+      goto finished;
+    }
+    iNewLevel = iMaxLevel;
+    bIgnoreEmpty = 1;
+
+  }else{
+    /* This call is to merge all segments at level iLevel. find the next
+    ** available segment index at level iLevel+1. The call to
+    ** fts3AllocateSegdirIdx() will merge the segments at level iLevel+1 to
+    ** a single iLevel+2 segment if necessary.  */
+    assert( FTS3_SEGCURSOR_PENDING==-1 );
+    iNewLevel = getAbsoluteLevel(p, iLangid, iIndex, iLevel+1);
+    rc = fts3AllocateSegdirIdx(p, iLangid, iIndex, iLevel+1, &iIdx);
+    bIgnoreEmpty = (iLevel!=FTS3_SEGCURSOR_PENDING) && (iNewLevel>iMaxLevel);
+  }
+  if( rc!=SQLITE_OK ) goto finished;
+
+  assert( csr.nSegment>0 );
+  assert_fts3_nc( iNewLevel>=getAbsoluteLevel(p, iLangid, iIndex, 0) );
+  assert_fts3_nc(
+    iNewLevel<getAbsoluteLevel(p, iLangid, iIndex,FTS3_SEGDIR_MAXLEVEL)
+  );
+
+  memset(&filter, 0, sizeof(Fts3SegFilter));
+  filter.flags = FTS3_SEGMENT_REQUIRE_POS;
+  filter.flags |= (bIgnoreEmpty ? FTS3_SEGMENT_IGNORE_EMPTY : 0);
+
+  rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
+  while( SQLITE_OK==rc ){
+    rc = sqlite3Fts3SegReaderStep(p, &csr);
+    if( rc!=SQLITE_ROW ) break;
+    rc = fts3SegWriterAdd(p, &pWriter, 1,
+        csr.zTerm, csr.nTerm, csr.aDoclist, csr.nDoclist);
+  }
+  if( rc!=SQLITE_OK ) goto finished;
+  assert_fts3_nc( pWriter || bIgnoreEmpty );
+
+  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
+    rc = fts3DeleteSegdir(
+        p, iLangid, iIndex, iLevel, csr.apSegment, csr.nSegment
+    );
+    if( rc!=SQLITE_OK ) goto finished;
+  }
+  if( pWriter ){
+    rc = fts3SegWriterFlush(p, pWriter, iNewLevel, iIdx);
+    if( rc==SQLITE_OK ){
+      if( iLevel==FTS3_SEGCURSOR_PENDING || iNewLevel<iMaxLevel ){
+        rc = fts3PromoteSegments(p, iNewLevel, pWriter->nLeafData);
+      }
+    }
+  }
+
+ finished:
+  fts3SegWriterFree(pWriter);
+  sqlite3Fts3SegReaderFinish(&csr);
+  return rc;
+}
+
+
+/*
+** Flush the contents of pendingTerms to level 0 segments.
+*/
+SQLITE_PRIVATE int sqlite3Fts3PendingTermsFlush(Fts3Table *p){
+  int rc = SQLITE_OK;
+  int i;
+
+  for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
+    rc = fts3SegmentMerge(p, p->iPrevLangid, i, FTS3_SEGCURSOR_PENDING);
+    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  }
+
+  /* Determine the auto-incr-merge setting if unknown.  If enabled,
+  ** estimate the number of leaf blocks of content to be written
+  */
+  if( rc==SQLITE_OK && p->bHasStat
+   && p->nAutoincrmerge==0xff && p->nLeafAdd>0
+  ){
+    sqlite3_stmt *pStmt = 0;
+    rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int(pStmt, 1, FTS_STAT_AUTOINCRMERGE);
+      rc = sqlite3_step(pStmt);
+      if( rc==SQLITE_ROW ){
+        p->nAutoincrmerge = sqlite3_column_int(pStmt, 0);
+        if( p->nAutoincrmerge==1 ) p->nAutoincrmerge = 8;
+      }else if( rc==SQLITE_DONE ){
+        p->nAutoincrmerge = 0;
+      }
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sqlite3Fts3PendingTermsClear(p);
+  }
+  return rc;
+}
+
+/*
+** Encode N integers as varints into a blob.
+*/
+static void fts3EncodeIntArray(
+  int N,             /* The number of integers to encode */
+  u32 *a,            /* The integer values */
+  char *zBuf,        /* Write the BLOB here */
+  int *pNBuf         /* Write number of bytes if zBuf[] used here */
+){
+  int i, j;
+  for(i=j=0; i<N; i++){
+    j += sqlite3Fts3PutVarint(&zBuf[j], (sqlite3_int64)a[i]);
+  }
+  *pNBuf = j;
+}
+
+/*
+** Decode a blob of varints into N integers
+*/
+static void fts3DecodeIntArray(
+  int N,             /* The number of integers to decode */
+  u32 *a,            /* Write the integer values */
+  const char *zBuf,  /* The BLOB containing the varints */
+  int nBuf           /* size of the BLOB */
+){
+  int i = 0;
+  if( nBuf && (zBuf[nBuf-1]&0x80)==0 ){
+    int j;
+    for(i=j=0; i<N && j<nBuf; i++){
+      sqlite3_int64 x;
+      j += sqlite3Fts3GetVarint(&zBuf[j], &x);
+      a[i] = (u32)(x & 0xffffffff);
+    }
+  }
+  while( i<N ) a[i++] = 0;
+}
+
+/*
+** Insert the sizes (in tokens) for each column of the document
+** with docid equal to p->iPrevDocid.  The sizes are encoded as
+** a blob of varints.
+*/
+static void fts3InsertDocsize(
+  int *pRC,                       /* Result code */
+  Fts3Table *p,                   /* Table into which to insert */
+  u32 *aSz                        /* Sizes of each column, in tokens */
+){
+  char *pBlob;             /* The BLOB encoding of the document size */
+  int nBlob;               /* Number of bytes in the BLOB */
+  sqlite3_stmt *pStmt;     /* Statement used to insert the encoding */
+  int rc;                  /* Result code from subfunctions */
+
+  if( *pRC ) return;
+  pBlob = sqlite3_malloc64( 10*(sqlite3_int64)p->nColumn );
+  if( pBlob==0 ){
+    *pRC = SQLITE_NOMEM;
+    return;
+  }
+  fts3EncodeIntArray(p->nColumn, aSz, pBlob, &nBlob);
+  rc = fts3SqlStmt(p, SQL_REPLACE_DOCSIZE, &pStmt, 0);
+  if( rc ){
+    sqlite3_free(pBlob);
+    *pRC = rc;
+    return;
+  }
+  sqlite3_bind_int64(pStmt, 1, p->iPrevDocid);
+  sqlite3_bind_blob(pStmt, 2, pBlob, nBlob, sqlite3_free);
+  sqlite3_step(pStmt);
+  *pRC = sqlite3_reset(pStmt);
+}
+
+/*
+** Record 0 of the %_stat table contains a blob consisting of N varints,
+** where N is the number of user defined columns in the fts3 table plus
+** two. If nCol is the number of user defined columns, then values of the
+** varints are set as follows:
+**
+**   Varint 0:       Total number of rows in the table.
+**
+**   Varint 1..nCol: For each column, the total number of tokens stored in
+**                   the column for all rows of the table.
+**
+**   Varint 1+nCol:  The total size, in bytes, of all text values in all
+**                   columns of all rows of the table.
+**
+*/
+static void fts3UpdateDocTotals(
+  int *pRC,                       /* The result code */
+  Fts3Table *p,                   /* Table being updated */
+  u32 *aSzIns,                    /* Size increases */
+  u32 *aSzDel,                    /* Size decreases */
+  int nChng                       /* Change in the number of documents */
+){
+  char *pBlob;             /* Storage for BLOB written into %_stat */
+  int nBlob;               /* Size of BLOB written into %_stat */
+  u32 *a;                  /* Array of integers that becomes the BLOB */
+  sqlite3_stmt *pStmt;     /* Statement for reading and writing */
+  int i;                   /* Loop counter */
+  int rc;                  /* Result code from subfunctions */
+
+  const int nStat = p->nColumn+2;
+
+  if( *pRC ) return;
+  a = sqlite3_malloc64( (sizeof(u32)+10)*(sqlite3_int64)nStat );
+  if( a==0 ){
+    *pRC = SQLITE_NOMEM;
+    return;
+  }
+  pBlob = (char*)&a[nStat];
+  rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pStmt, 0);
+  if( rc ){
+    sqlite3_free(a);
+    *pRC = rc;
+    return;
+  }
+  sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
+  if( sqlite3_step(pStmt)==SQLITE_ROW ){
+    fts3DecodeIntArray(nStat, a,
+         sqlite3_column_blob(pStmt, 0),
+         sqlite3_column_bytes(pStmt, 0));
+  }else{
+    memset(a, 0, sizeof(u32)*(nStat) );
+  }
+  rc = sqlite3_reset(pStmt);
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(a);
+    *pRC = rc;
+    return;
+  }
+  if( nChng<0 && a[0]<(u32)(-nChng) ){
+    a[0] = 0;
+  }else{
+    a[0] += nChng;
+  }
+  for(i=0; i<p->nColumn+1; i++){
+    u32 x = a[i+1];
+    if( x+aSzIns[i] < aSzDel[i] ){
+      x = 0;
+    }else{
+      x = x + aSzIns[i] - aSzDel[i];
+    }
+    a[i+1] = x;
+  }
+  fts3EncodeIntArray(nStat, a, pBlob, &nBlob);
+  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pStmt, 0);
+  if( rc ){
+    sqlite3_free(a);
+    *pRC = rc;
+    return;
+  }
+  sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
+  sqlite3_bind_blob(pStmt, 2, pBlob, nBlob, SQLITE_STATIC);
+  sqlite3_step(pStmt);
+  *pRC = sqlite3_reset(pStmt);
+  sqlite3_bind_null(pStmt, 2);
+  sqlite3_free(a);
+}
+
+/*
+** Merge the entire database so that there is one segment for each
+** iIndex/iLangid combination.
+*/
+static int fts3DoOptimize(Fts3Table *p, int bReturnDone){
+  int bSeenDone = 0;
+  int rc;
+  sqlite3_stmt *pAllLangid = 0;
+
+  rc = sqlite3Fts3PendingTermsFlush(p);
+  if( rc==SQLITE_OK ){
+    rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
+  }
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int(pAllLangid, 1, p->iPrevLangid);
+    sqlite3_bind_int(pAllLangid, 2, p->nIndex);
+    while( sqlite3_step(pAllLangid)==SQLITE_ROW ){
+      int i;
+      int iLangid = sqlite3_column_int(pAllLangid, 0);
+      for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
+        rc = fts3SegmentMerge(p, iLangid, i, FTS3_SEGCURSOR_ALL);
+        if( rc==SQLITE_DONE ){
+          bSeenDone = 1;
+          rc = SQLITE_OK;
+        }
+      }
+    }
+    rc2 = sqlite3_reset(pAllLangid);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  sqlite3Fts3SegmentsClose(p);
+
+  return (rc==SQLITE_OK && bReturnDone && bSeenDone) ? SQLITE_DONE : rc;
+}
+
+/*
+** This function is called when the user executes the following statement:
+**
+**     INSERT INTO <tbl>(<tbl>) VALUES('rebuild');
+**
+** The entire FTS index is discarded and rebuilt. If the table is one
+** created using the content=xxx option, then the new index is based on
+** the current contents of the xxx table. Otherwise, it is rebuilt based
+** on the contents of the %_content table.
+*/
+static int fts3DoRebuild(Fts3Table *p){
+  int rc;                         /* Return Code */
+
+  rc = fts3DeleteAll(p, 0);
+  if( rc==SQLITE_OK ){
+    u32 *aSz = 0;
+    u32 *aSzIns = 0;
+    u32 *aSzDel = 0;
+    sqlite3_stmt *pStmt = 0;
+    int nEntry = 0;
+
+    /* Compose and prepare an SQL statement to loop through the content table */
+    char *zSql = sqlite3_mprintf("SELECT %s" , p->zReadExprlist);
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
+      sqlite3_free(zSql);
+    }
+
+    if( rc==SQLITE_OK ){
+      sqlite3_int64 nByte = sizeof(u32) * ((sqlite3_int64)p->nColumn+1)*3;
+      aSz = (u32 *)sqlite3_malloc64(nByte);
+      if( aSz==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(aSz, 0, nByte);
+        aSzIns = &aSz[p->nColumn+1];
+        aSzDel = &aSzIns[p->nColumn+1];
+      }
+    }
+
+    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      int iCol;
+      int iLangid = langidFromSelect(p, pStmt);
+      rc = fts3PendingTermsDocid(p, 0, iLangid, sqlite3_column_int64(pStmt, 0));
+      memset(aSz, 0, sizeof(aSz[0]) * (p->nColumn+1));
+      for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
+        if( p->abNotindexed[iCol]==0 ){
+          const char *z = (const char *) sqlite3_column_text(pStmt, iCol+1);
+          rc = fts3PendingTermsAdd(p, iLangid, z, iCol, &aSz[iCol]);
+          aSz[p->nColumn] += sqlite3_column_bytes(pStmt, iCol+1);
+        }
+      }
+      if( p->bHasDocsize ){
+        fts3InsertDocsize(&rc, p, aSz);
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3_finalize(pStmt);
+        pStmt = 0;
+      }else{
+        nEntry++;
+        for(iCol=0; iCol<=p->nColumn; iCol++){
+          aSzIns[iCol] += aSz[iCol];
+        }
+      }
+    }
+    if( p->bFts4 ){
+      fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nEntry);
+    }
+    sqlite3_free(aSz);
+
+    if( pStmt ){
+      int rc2 = sqlite3_finalize(pStmt);
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+  }
+
+  return rc;
+}
+
+
+/*
+** This function opens a cursor used to read the input data for an
+** incremental merge operation. Specifically, it opens a cursor to scan
+** the oldest nSeg segments (idx=0 through idx=(nSeg-1)) in absolute
+** level iAbsLevel.
+*/
+static int fts3IncrmergeCsr(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level to open */
+  int nSeg,                       /* Number of segments to merge */
+  Fts3MultiSegReader *pCsr        /* Cursor object to populate */
+){
+  int rc;                         /* Return Code */
+  sqlite3_stmt *pStmt = 0;        /* Statement used to read %_segdir entry */
+  sqlite3_int64 nByte;            /* Bytes allocated at pCsr->apSegment[] */
+
+  /* Allocate space for the Fts3MultiSegReader.aCsr[] array */
+  memset(pCsr, 0, sizeof(*pCsr));
+  nByte = sizeof(Fts3SegReader *) * nSeg;
+  pCsr->apSegment = (Fts3SegReader **)sqlite3_malloc64(nByte);
+
+  if( pCsr->apSegment==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    memset(pCsr->apSegment, 0, nByte);
+    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
+  }
+  if( rc==SQLITE_OK ){
+    int i;
+    int rc2;
+    sqlite3_bind_int64(pStmt, 1, iAbsLevel);
+    assert( pCsr->nSegment==0 );
+    for(i=0; rc==SQLITE_OK && sqlite3_step(pStmt)==SQLITE_ROW && i<nSeg; i++){
+      rc = sqlite3Fts3SegReaderNew(i, 0,
+          sqlite3_column_int64(pStmt, 1),        /* segdir.start_block */
+          sqlite3_column_int64(pStmt, 2),        /* segdir.leaves_end_block */
+          sqlite3_column_int64(pStmt, 3),        /* segdir.end_block */
+          sqlite3_column_blob(pStmt, 4),         /* segdir.root */
+          sqlite3_column_bytes(pStmt, 4),        /* segdir.root */
+          &pCsr->apSegment[i]
+      );
+      pCsr->nSegment++;
+    }
+    rc2 = sqlite3_reset(pStmt);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  return rc;
+}
+
+typedef struct IncrmergeWriter IncrmergeWriter;
+typedef struct NodeWriter NodeWriter;
+typedef struct Blob Blob;
+typedef struct NodeReader NodeReader;
+
+/*
+** An instance of the following structure is used as a dynamic buffer
+** to build up nodes or other blobs of data in.
+**
+** The function blobGrowBuffer() is used to extend the allocation.
+*/
+struct Blob {
+  char *a;                        /* Pointer to allocation */
+  int n;                          /* Number of valid bytes of data in a[] */
+  int nAlloc;                     /* Allocated size of a[] (nAlloc>=n) */
+};
+
+/*
+** This structure is used to build up buffers containing segment b-tree
+** nodes (blocks).
+*/
+struct NodeWriter {
+  sqlite3_int64 iBlock;           /* Current block id */
+  Blob key;                       /* Last key written to the current block */
+  Blob block;                     /* Current block image */
+};
+
+/*
+** An object of this type contains the state required to create or append
+** to an appendable b-tree segment.
+*/
+struct IncrmergeWriter {
+  int nLeafEst;                   /* Space allocated for leaf blocks */
+  int nWork;                      /* Number of leaf pages flushed */
+  sqlite3_int64 iAbsLevel;        /* Absolute level of input segments */
+  int iIdx;                       /* Index of *output* segment in iAbsLevel+1 */
+  sqlite3_int64 iStart;           /* Block number of first allocated block */
+  sqlite3_int64 iEnd;             /* Block number of last allocated block */
+  sqlite3_int64 nLeafData;        /* Bytes of leaf page data so far */
+  u8 bNoLeafData;                 /* If true, store 0 for segment size */
+  NodeWriter aNodeWriter[FTS_MAX_APPENDABLE_HEIGHT];
+};
+
+/*
+** An object of the following type is used to read data from a single
+** FTS segment node. See the following functions:
+**
+**     nodeReaderInit()
+**     nodeReaderNext()
+**     nodeReaderRelease()
+*/
+struct NodeReader {
+  const char *aNode;
+  int nNode;
+  int iOff;                       /* Current offset within aNode[] */
+
+  /* Output variables. Containing the current node entry. */
+  sqlite3_int64 iChild;           /* Pointer to child node */
+  Blob term;                      /* Current term */
+  const char *aDoclist;           /* Pointer to doclist */
+  int nDoclist;                   /* Size of doclist in bytes */
+};
+
+/*
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, if the allocation at pBlob->a is not already at least nMin
+** bytes in size, extend (realloc) it to be so.
+**
+** If an OOM error occurs, set *pRc to SQLITE_NOMEM and leave pBlob->a
+** unmodified. Otherwise, if the allocation succeeds, update pBlob->nAlloc
+** to reflect the new size of the pBlob->a[] buffer.
+*/
+static void blobGrowBuffer(Blob *pBlob, int nMin, int *pRc){
+  if( *pRc==SQLITE_OK && nMin>pBlob->nAlloc ){
+    int nAlloc = nMin;
+    char *a = (char *)sqlite3_realloc64(pBlob->a, nAlloc);
+    if( a ){
+      pBlob->nAlloc = nAlloc;
+      pBlob->a = a;
+    }else{
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+}
+
+/*
+** Attempt to advance the node-reader object passed as the first argument to
+** the next entry on the node.
+**
+** Return an error code if an error occurs (SQLITE_NOMEM is possible).
+** Otherwise return SQLITE_OK. If there is no next entry on the node
+** (e.g. because the current entry is the last) set NodeReader->aNode to
+** NULL to indicate EOF. Otherwise, populate the NodeReader structure output
+** variables for the new entry.
+*/
+static int nodeReaderNext(NodeReader *p){
+  int bFirst = (p->term.n==0);    /* True for first term on the node */
+  int nPrefix = 0;                /* Bytes to copy from previous term */
+  int nSuffix = 0;                /* Bytes to append to the prefix */
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( p->aNode );
+  if( p->iChild && bFirst==0 ) p->iChild++;
+  if( p->iOff>=p->nNode ){
+    /* EOF */
+    p->aNode = 0;
+  }else{
+    if( bFirst==0 ){
+      p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &nPrefix);
+    }
+    p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &nSuffix);
+
+    if( nPrefix>p->term.n || nSuffix>p->nNode-p->iOff || nSuffix==0 ){
+      return FTS_CORRUPT_VTAB;
+    }
+    blobGrowBuffer(&p->term, nPrefix+nSuffix, &rc);
+    if( rc==SQLITE_OK && ALWAYS(p->term.a!=0) ){
+      memcpy(&p->term.a[nPrefix], &p->aNode[p->iOff], nSuffix);
+      p->term.n = nPrefix+nSuffix;
+      p->iOff += nSuffix;
+      if( p->iChild==0 ){
+        p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &p->nDoclist);
+        if( (p->nNode-p->iOff)<p->nDoclist ){
+          return FTS_CORRUPT_VTAB;
+        }
+        p->aDoclist = &p->aNode[p->iOff];
+        p->iOff += p->nDoclist;
+      }
+    }
+  }
+
+  assert_fts3_nc( p->iOff<=p->nNode );
+  return rc;
+}
+
+/*
+** Release all dynamic resources held by node-reader object *p.
+*/
+static void nodeReaderRelease(NodeReader *p){
+  sqlite3_free(p->term.a);
+}
+
+/*
+** Initialize a node-reader object to read the node in buffer aNode/nNode.
+**
+** If successful, SQLITE_OK is returned and the NodeReader object set to
+** point to the first entry on the node (if any). Otherwise, an SQLite
+** error code is returned.
+*/
+static int nodeReaderInit(NodeReader *p, const char *aNode, int nNode){
+  memset(p, 0, sizeof(NodeReader));
+  p->aNode = aNode;
+  p->nNode = nNode;
+
+  /* Figure out if this is a leaf or an internal node. */
+  if( aNode && aNode[0] ){
+    /* An internal node. */
+    p->iOff = 1 + sqlite3Fts3GetVarint(&p->aNode[1], &p->iChild);
+  }else{
+    p->iOff = 1;
+  }
+
+  return aNode ? nodeReaderNext(p) : SQLITE_OK;
+}
+
+/*
+** This function is called while writing an FTS segment each time a leaf o
+** node is finished and written to disk. The key (zTerm/nTerm) is guaranteed
+** to be greater than the largest key on the node just written, but smaller
+** than or equal to the first key that will be written to the next leaf
+** node.
+**
+** The block id of the leaf node just written to disk may be found in
+** (pWriter->aNodeWriter[0].iBlock) when this function is called.
+*/
+static int fts3IncrmergePush(
+  Fts3Table *p,                   /* Fts3 table handle */
+  IncrmergeWriter *pWriter,       /* Writer object */
+  const char *zTerm,              /* Term to write to internal node */
+  int nTerm                       /* Bytes at zTerm */
+){
+  sqlite3_int64 iPtr = pWriter->aNodeWriter[0].iBlock;
+  int iLayer;
+
+  assert( nTerm>0 );
+  for(iLayer=1; ALWAYS(iLayer<FTS_MAX_APPENDABLE_HEIGHT); iLayer++){
+    sqlite3_int64 iNextPtr = 0;
+    NodeWriter *pNode = &pWriter->aNodeWriter[iLayer];
+    int rc = SQLITE_OK;
+    int nPrefix;
+    int nSuffix;
+    int nSpace;
+
+    /* Figure out how much space the key will consume if it is written to
+    ** the current node of layer iLayer. Due to the prefix compression,
+    ** the space required changes depending on which node the key is to
+    ** be added to.  */
+    nPrefix = fts3PrefixCompress(pNode->key.a, pNode->key.n, zTerm, nTerm);
+    nSuffix = nTerm - nPrefix;
+    if(nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+    nSpace  = sqlite3Fts3VarintLen(nPrefix);
+    nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
+
+    if( pNode->key.n==0 || (pNode->block.n + nSpace)<=p->nNodeSize ){
+      /* If the current node of layer iLayer contains zero keys, or if adding
+      ** the key to it will not cause it to grow to larger than nNodeSize
+      ** bytes in size, write the key here.  */
+
+      Blob *pBlk = &pNode->block;
+      if( pBlk->n==0 ){
+        blobGrowBuffer(pBlk, p->nNodeSize, &rc);
+        if( rc==SQLITE_OK ){
+          pBlk->a[0] = (char)iLayer;
+          pBlk->n = 1 + sqlite3Fts3PutVarint(&pBlk->a[1], iPtr);
+        }
+      }
+      blobGrowBuffer(pBlk, pBlk->n + nSpace, &rc);
+      blobGrowBuffer(&pNode->key, nTerm, &rc);
+
+      if( rc==SQLITE_OK ){
+        if( pNode->key.n ){
+          pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nPrefix);
+        }
+        pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nSuffix);
+        assert( nPrefix+nSuffix<=nTerm );
+        assert( nPrefix>=0 );
+        memcpy(&pBlk->a[pBlk->n], &zTerm[nPrefix], nSuffix);
+        pBlk->n += nSuffix;
+
+        memcpy(pNode->key.a, zTerm, nTerm);
+        pNode->key.n = nTerm;
+      }
+    }else{
+      /* Otherwise, flush the current node of layer iLayer to disk.
+      ** Then allocate a new, empty sibling node. The key will be written
+      ** into the parent of this node. */
+      rc = fts3WriteSegment(p, pNode->iBlock, pNode->block.a, pNode->block.n);
+
+      assert( pNode->block.nAlloc>=p->nNodeSize );
+      pNode->block.a[0] = (char)iLayer;
+      pNode->block.n = 1 + sqlite3Fts3PutVarint(&pNode->block.a[1], iPtr+1);
+
+      iNextPtr = pNode->iBlock;
+      pNode->iBlock++;
+      pNode->key.n = 0;
+    }
+
+    if( rc!=SQLITE_OK || iNextPtr==0 ) return rc;
+    iPtr = iNextPtr;
+  }
+
+  assert( 0 );
+  return 0;
+}
+
+/*
+** Append a term and (optionally) doclist to the FTS segment node currently
+** stored in blob *pNode. The node need not contain any terms, but the
+** header must be written before this function is called.
+**
+** A node header is a single 0x00 byte for a leaf node, or a height varint
+** followed by the left-hand-child varint for an internal node.
+**
+** The term to be appended is passed via arguments zTerm/nTerm. For a
+** leaf node, the doclist is passed as aDoclist/nDoclist. For an internal
+** node, both aDoclist and nDoclist must be passed 0.
+**
+** If the size of the value in blob pPrev is zero, then this is the first
+** term written to the node. Otherwise, pPrev contains a copy of the
+** previous term. Before this function returns, it is updated to contain a
+** copy of zTerm/nTerm.
+**
+** It is assumed that the buffer associated with pNode is already large
+** enough to accommodate the new entry. The buffer associated with pPrev
+** is extended by this function if requrired.
+**
+** If an error (i.e. OOM condition) occurs, an SQLite error code is
+** returned. Otherwise, SQLITE_OK.
+*/
+static int fts3AppendToNode(
+  Blob *pNode,                    /* Current node image to append to */
+  Blob *pPrev,                    /* Buffer containing previous term written */
+  const char *zTerm,              /* New term to write */
+  int nTerm,                      /* Size of zTerm in bytes */
+  const char *aDoclist,           /* Doclist (or NULL) to write */
+  int nDoclist                    /* Size of aDoclist in bytes */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int bFirst = (pPrev->n==0);     /* True if this is the first term written */
+  int nPrefix;                    /* Size of term prefix in bytes */
+  int nSuffix;                    /* Size of term suffix in bytes */
+
+  /* Node must have already been started. There must be a doclist for a
+  ** leaf node, and there must not be a doclist for an internal node.  */
+  assert( pNode->n>0 );
+  assert_fts3_nc( (pNode->a[0]=='\0')==(aDoclist!=0) );
+
+  blobGrowBuffer(pPrev, nTerm, &rc);
+  if( rc!=SQLITE_OK ) return rc;
+  assert( pPrev!=0 );
+  assert( pPrev->a!=0 );
+
+  nPrefix = fts3PrefixCompress(pPrev->a, pPrev->n, zTerm, nTerm);
+  nSuffix = nTerm - nPrefix;
+  if( nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+  memcpy(pPrev->a, zTerm, nTerm);
+  pPrev->n = nTerm;
+
+  if( bFirst==0 ){
+    pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nPrefix);
+  }
+  pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nSuffix);
+  memcpy(&pNode->a[pNode->n], &zTerm[nPrefix], nSuffix);
+  pNode->n += nSuffix;
+
+  if( aDoclist ){
+    pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nDoclist);
+    memcpy(&pNode->a[pNode->n], aDoclist, nDoclist);
+    pNode->n += nDoclist;
+  }
+
+  assert( pNode->n<=pNode->nAlloc );
+
+  return SQLITE_OK;
+}
+
+/*
+** Append the current term and doclist pointed to by cursor pCsr to the
+** appendable b-tree segment opened for writing by pWriter.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise.
+*/
+static int fts3IncrmergeAppend(
+  Fts3Table *p,                   /* Fts3 table handle */
+  IncrmergeWriter *pWriter,       /* Writer object */
+  Fts3MultiSegReader *pCsr        /* Cursor containing term and doclist */
+){
+  const char *zTerm = pCsr->zTerm;
+  int nTerm = pCsr->nTerm;
+  const char *aDoclist = pCsr->aDoclist;
+  int nDoclist = pCsr->nDoclist;
+  int rc = SQLITE_OK;           /* Return code */
+  int nSpace;                   /* Total space in bytes required on leaf */
+  int nPrefix;                  /* Size of prefix shared with previous term */
+  int nSuffix;                  /* Size of suffix (nTerm - nPrefix) */
+  NodeWriter *pLeaf;            /* Object used to write leaf nodes */
+
+  pLeaf = &pWriter->aNodeWriter[0];
+  nPrefix = fts3PrefixCompress(pLeaf->key.a, pLeaf->key.n, zTerm, nTerm);
+  nSuffix = nTerm - nPrefix;
+  if(nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+
+  nSpace  = sqlite3Fts3VarintLen(nPrefix);
+  nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
+  nSpace += sqlite3Fts3VarintLen(nDoclist) + nDoclist;
+
+  /* If the current block is not empty, and if adding this term/doclist
+  ** to the current block would make it larger than Fts3Table.nNodeSize bytes,
+  ** and if there is still room for another leaf page, write this block out to
+  ** the database. */
+  if( pLeaf->block.n>0
+   && (pLeaf->block.n + nSpace)>p->nNodeSize
+   && pLeaf->iBlock < (pWriter->iStart + pWriter->nLeafEst)
+  ){
+    rc = fts3WriteSegment(p, pLeaf->iBlock, pLeaf->block.a, pLeaf->block.n);
+    pWriter->nWork++;
+
+    /* Add the current term to the parent node. The term added to the
+    ** parent must:
+    **
+    **   a) be greater than the largest term on the leaf node just written
+    **      to the database (still available in pLeaf->key), and
+    **
+    **   b) be less than or equal to the term about to be added to the new
+    **      leaf node (zTerm/nTerm).
+    **
+    ** In other words, it must be the prefix of zTerm 1 byte longer than
+    ** the common prefix (if any) of zTerm and pWriter->zTerm.
+    */
+    if( rc==SQLITE_OK ){
+      rc = fts3IncrmergePush(p, pWriter, zTerm, nPrefix+1);
+    }
+
+    /* Advance to the next output block */
+    pLeaf->iBlock++;
+    pLeaf->key.n = 0;
+    pLeaf->block.n = 0;
+
+    nSuffix = nTerm;
+    nSpace  = 1;
+    nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
+    nSpace += sqlite3Fts3VarintLen(nDoclist) + nDoclist;
+  }
+
+  pWriter->nLeafData += nSpace;
+  blobGrowBuffer(&pLeaf->block, pLeaf->block.n + nSpace, &rc);
+  if( rc==SQLITE_OK ){
+    if( pLeaf->block.n==0 ){
+      pLeaf->block.n = 1;
+      pLeaf->block.a[0] = '\0';
+    }
+    rc = fts3AppendToNode(
+        &pLeaf->block, &pLeaf->key, zTerm, nTerm, aDoclist, nDoclist
+    );
+  }
+
+  return rc;
+}
+
+/*
+** This function is called to release all dynamic resources held by the
+** merge-writer object pWriter, and if no error has occurred, to flush
+** all outstanding node buffers held by pWriter to disk.
+**
+** If *pRc is not SQLITE_OK when this function is called, then no attempt
+** is made to write any data to disk. Instead, this function serves only
+** to release outstanding resources.
+**
+** Otherwise, if *pRc is initially SQLITE_OK and an error occurs while
+** flushing buffers to disk, *pRc is set to an SQLite error code before
+** returning.
+*/
+static void fts3IncrmergeRelease(
+  Fts3Table *p,                   /* FTS3 table handle */
+  IncrmergeWriter *pWriter,       /* Merge-writer object */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  int i;                          /* Used to iterate through non-root layers */
+  int iRoot;                      /* Index of root in pWriter->aNodeWriter */
+  NodeWriter *pRoot;              /* NodeWriter for root node */
+  int rc = *pRc;                  /* Error code */
+
+  /* Set iRoot to the index in pWriter->aNodeWriter[] of the output segment
+  ** root node. If the segment fits entirely on a single leaf node, iRoot
+  ** will be set to 0. If the root node is the parent of the leaves, iRoot
+  ** will be 1. And so on.  */
+  for(iRoot=FTS_MAX_APPENDABLE_HEIGHT-1; iRoot>=0; iRoot--){
+    NodeWriter *pNode = &pWriter->aNodeWriter[iRoot];
+    if( pNode->block.n>0 ) break;
+    assert( *pRc || pNode->block.nAlloc==0 );
+    assert( *pRc || pNode->key.nAlloc==0 );
+    sqlite3_free(pNode->block.a);
+    sqlite3_free(pNode->key.a);
+  }
+
+  /* Empty output segment. This is a no-op. */
+  if( iRoot<0 ) return;
+
+  /* The entire output segment fits on a single node. Normally, this means
+  ** the node would be stored as a blob in the "root" column of the %_segdir
+  ** table. However, this is not permitted in this case. The problem is that
+  ** space has already been reserved in the %_segments table, and so the
+  ** start_block and end_block fields of the %_segdir table must be populated.
+  ** And, by design or by accident, released versions of FTS cannot handle
+  ** segments that fit entirely on the root node with start_block!=0.
+  **
+  ** Instead, create a synthetic root node that contains nothing but a
+  ** pointer to the single content node. So that the segment consists of a
+  ** single leaf and a single interior (root) node.
+  **
+  ** Todo: Better might be to defer allocating space in the %_segments
+  ** table until we are sure it is needed.
+  */
+  if( iRoot==0 ){
+    Blob *pBlock = &pWriter->aNodeWriter[1].block;
+    blobGrowBuffer(pBlock, 1 + FTS3_VARINT_MAX, &rc);
+    if( rc==SQLITE_OK ){
+      pBlock->a[0] = 0x01;
+      pBlock->n = 1 + sqlite3Fts3PutVarint(
+          &pBlock->a[1], pWriter->aNodeWriter[0].iBlock
+      );
+    }
+    iRoot = 1;
+  }
+  pRoot = &pWriter->aNodeWriter[iRoot];
+
+  /* Flush all currently outstanding nodes to disk. */
+  for(i=0; i<iRoot; i++){
+    NodeWriter *pNode = &pWriter->aNodeWriter[i];
+    if( pNode->block.n>0 && rc==SQLITE_OK ){
+      rc = fts3WriteSegment(p, pNode->iBlock, pNode->block.a, pNode->block.n);
+    }
+    sqlite3_free(pNode->block.a);
+    sqlite3_free(pNode->key.a);
+  }
+
+  /* Write the %_segdir record. */
+  if( rc==SQLITE_OK ){
+    rc = fts3WriteSegdir(p,
+        pWriter->iAbsLevel+1,               /* level */
+        pWriter->iIdx,                      /* idx */
+        pWriter->iStart,                    /* start_block */
+        pWriter->aNodeWriter[0].iBlock,     /* leaves_end_block */
+        pWriter->iEnd,                      /* end_block */
+        (pWriter->bNoLeafData==0 ? pWriter->nLeafData : 0),   /* end_block */
+        pRoot->block.a, pRoot->block.n      /* root */
+    );
+  }
+  sqlite3_free(pRoot->block.a);
+  sqlite3_free(pRoot->key.a);
+
+  *pRc = rc;
+}
+
+/*
+** Compare the term in buffer zLhs (size in bytes nLhs) with that in
+** zRhs (size in bytes nRhs) using memcmp. If one term is a prefix of
+** the other, it is considered to be smaller than the other.
+**
+** Return -ve if zLhs is smaller than zRhs, 0 if it is equal, or +ve
+** if it is greater.
+*/
+static int fts3TermCmp(
+  const char *zLhs, int nLhs,     /* LHS of comparison */
+  const char *zRhs, int nRhs      /* RHS of comparison */
+){
+  int nCmp = MIN(nLhs, nRhs);
+  int res;
+
+  if( nCmp && ALWAYS(zLhs) && ALWAYS(zRhs) ){
+    res = memcmp(zLhs, zRhs, nCmp);
+  }else{
+    res = 0;
+  }
+  if( res==0 ) res = nLhs - nRhs;
+
+  return res;
+}
+
+
+/*
+** Query to see if the entry in the %_segments table with blockid iEnd is
+** NULL. If no error occurs and the entry is NULL, set *pbRes 1 before
+** returning. Otherwise, set *pbRes to 0.
+**
+** Or, if an error occurs while querying the database, return an SQLite
+** error code. The final value of *pbRes is undefined in this case.
+**
+** This is used to test if a segment is an "appendable" segment. If it
+** is, then a NULL entry has been inserted into the %_segments table
+** with blockid %_segdir.end_block.
+*/
+static int fts3IsAppendable(Fts3Table *p, sqlite3_int64 iEnd, int *pbRes){
+  int bRes = 0;                   /* Result to set *pbRes to */
+  sqlite3_stmt *pCheck = 0;       /* Statement to query database with */
+  int rc;                         /* Return code */
+
+  rc = fts3SqlStmt(p, SQL_SEGMENT_IS_APPENDABLE, &pCheck, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pCheck, 1, iEnd);
+    if( SQLITE_ROW==sqlite3_step(pCheck) ) bRes = 1;
+    rc = sqlite3_reset(pCheck);
+  }
+
+  *pbRes = bRes;
+  return rc;
+}
+
+/*
+** This function is called when initializing an incremental-merge operation.
+** It checks if the existing segment with index value iIdx at absolute level
+** (iAbsLevel+1) can be appended to by the incremental merge. If it can, the
+** merge-writer object *pWriter is initialized to write to it.
+**
+** An existing segment can be appended to by an incremental merge if:
+**
+**   * It was initially created as an appendable segment (with all required
+**     space pre-allocated), and
+**
+**   * The first key read from the input (arguments zKey and nKey) is
+**     greater than the largest key currently stored in the potential
+**     output segment.
+*/
+static int fts3IncrmergeLoad(
+  Fts3Table *p,                   /* Fts3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level of input segments */
+  int iIdx,                       /* Index of candidate output segment */
+  const char *zKey,               /* First key to write */
+  int nKey,                       /* Number of bytes in nKey */
+  IncrmergeWriter *pWriter        /* Populate this object */
+){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pSelect = 0;      /* SELECT to read %_segdir entry */
+
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR, &pSelect, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_int64 iStart = 0;     /* Value of %_segdir.start_block */
+    sqlite3_int64 iLeafEnd = 0;   /* Value of %_segdir.leaves_end_block */
+    sqlite3_int64 iEnd = 0;       /* Value of %_segdir.end_block */
+    const char *aRoot = 0;        /* Pointer to %_segdir.root buffer */
+    int nRoot = 0;                /* Size of aRoot[] in bytes */
+    int rc2;                      /* Return code from sqlite3_reset() */
+    int bAppendable = 0;          /* Set to true if segment is appendable */
+
+    /* Read the %_segdir entry for index iIdx absolute level (iAbsLevel+1) */
+    sqlite3_bind_int64(pSelect, 1, iAbsLevel+1);
+    sqlite3_bind_int(pSelect, 2, iIdx);
+    if( sqlite3_step(pSelect)==SQLITE_ROW ){
+      iStart = sqlite3_column_int64(pSelect, 1);
+      iLeafEnd = sqlite3_column_int64(pSelect, 2);
+      fts3ReadEndBlockField(pSelect, 3, &iEnd, &pWriter->nLeafData);
+      if( pWriter->nLeafData<0 ){
+        pWriter->nLeafData = pWriter->nLeafData * -1;
+      }
+      pWriter->bNoLeafData = (pWriter->nLeafData==0);
+      nRoot = sqlite3_column_bytes(pSelect, 4);
+      aRoot = sqlite3_column_blob(pSelect, 4);
+      if( aRoot==0 ){
+        sqlite3_reset(pSelect);
+        return nRoot ? SQLITE_NOMEM : FTS_CORRUPT_VTAB;
+      }
+    }else{
+      return sqlite3_reset(pSelect);
+    }
+
+    /* Check for the zero-length marker in the %_segments table */
+    rc = fts3IsAppendable(p, iEnd, &bAppendable);
+
+    /* Check that zKey/nKey is larger than the largest key the candidate */
+    if( rc==SQLITE_OK && bAppendable ){
+      char *aLeaf = 0;
+      int nLeaf = 0;
+
+      rc = sqlite3Fts3ReadBlock(p, iLeafEnd, &aLeaf, &nLeaf, 0);
+      if( rc==SQLITE_OK ){
+        NodeReader reader;
+        for(rc = nodeReaderInit(&reader, aLeaf, nLeaf);
+            rc==SQLITE_OK && reader.aNode;
+            rc = nodeReaderNext(&reader)
+        ){
+          assert( reader.aNode );
+        }
+        if( fts3TermCmp(zKey, nKey, reader.term.a, reader.term.n)<=0 ){
+          bAppendable = 0;
+        }
+        nodeReaderRelease(&reader);
+      }
+      sqlite3_free(aLeaf);
+    }
+
+    if( rc==SQLITE_OK && bAppendable ){
+      /* It is possible to append to this segment. Set up the IncrmergeWriter
+      ** object to do so.  */
+      int i;
+      int nHeight = (int)aRoot[0];
+      NodeWriter *pNode;
+      if( nHeight<1 || nHeight>=FTS_MAX_APPENDABLE_HEIGHT ){
+        sqlite3_reset(pSelect);
+        return FTS_CORRUPT_VTAB;
+      }
+
+      pWriter->nLeafEst = (int)((iEnd - iStart) + 1)/FTS_MAX_APPENDABLE_HEIGHT;
+      pWriter->iStart = iStart;
+      pWriter->iEnd = iEnd;
+      pWriter->iAbsLevel = iAbsLevel;
+      pWriter->iIdx = iIdx;
+
+      for(i=nHeight+1; i<FTS_MAX_APPENDABLE_HEIGHT; i++){
+        pWriter->aNodeWriter[i].iBlock = pWriter->iStart + i*pWriter->nLeafEst;
+      }
+
+      pNode = &pWriter->aNodeWriter[nHeight];
+      pNode->iBlock = pWriter->iStart + pWriter->nLeafEst*nHeight;
+      blobGrowBuffer(&pNode->block,
+          MAX(nRoot, p->nNodeSize)+FTS3_NODE_PADDING, &rc
+      );
+      if( rc==SQLITE_OK ){
+        memcpy(pNode->block.a, aRoot, nRoot);
+        pNode->block.n = nRoot;
+        memset(&pNode->block.a[nRoot], 0, FTS3_NODE_PADDING);
+      }
+
+      for(i=nHeight; i>=0 && rc==SQLITE_OK; i--){
+        NodeReader reader;
+        memset(&reader, 0, sizeof(reader));
+        pNode = &pWriter->aNodeWriter[i];
+
+        if( pNode->block.a){
+          rc = nodeReaderInit(&reader, pNode->block.a, pNode->block.n);
+          while( reader.aNode && rc==SQLITE_OK ) rc = nodeReaderNext(&reader);
+          blobGrowBuffer(&pNode->key, reader.term.n, &rc);
+          if( rc==SQLITE_OK ){
+            assert_fts3_nc( reader.term.n>0 || reader.aNode==0 );
+            if( reader.term.n>0 ){
+              memcpy(pNode->key.a, reader.term.a, reader.term.n);
+            }
+            pNode->key.n = reader.term.n;
+            if( i>0 ){
+              char *aBlock = 0;
+              int nBlock = 0;
+              pNode = &pWriter->aNodeWriter[i-1];
+              pNode->iBlock = reader.iChild;
+              rc = sqlite3Fts3ReadBlock(p, reader.iChild, &aBlock, &nBlock,0);
+              blobGrowBuffer(&pNode->block,
+                  MAX(nBlock, p->nNodeSize)+FTS3_NODE_PADDING, &rc
+              );
+              if( rc==SQLITE_OK ){
+                memcpy(pNode->block.a, aBlock, nBlock);
+                pNode->block.n = nBlock;
+                memset(&pNode->block.a[nBlock], 0, FTS3_NODE_PADDING);
+              }
+              sqlite3_free(aBlock);
+            }
+          }
+        }
+        nodeReaderRelease(&reader);
+      }
+    }
+
+    rc2 = sqlite3_reset(pSelect);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  return rc;
+}
+
+/*
+** Determine the largest segment index value that exists within absolute
+** level iAbsLevel+1. If no error occurs, set *piIdx to this value plus
+** one before returning SQLITE_OK. Or, if there are no segments at all
+** within level iAbsLevel, set *piIdx to zero.
+**
+** If an error occurs, return an SQLite error code. The final value of
+** *piIdx is undefined in this case.
+*/
+static int fts3IncrmergeOutputIdx(
+  Fts3Table *p,                   /* FTS Table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute index of input segments */
+  int *piIdx                      /* OUT: Next free index at iAbsLevel+1 */
+){
+  int rc;
+  sqlite3_stmt *pOutputIdx = 0;   /* SQL used to find output index */
+
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pOutputIdx, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pOutputIdx, 1, iAbsLevel+1);
+    sqlite3_step(pOutputIdx);
+    *piIdx = sqlite3_column_int(pOutputIdx, 0);
+    rc = sqlite3_reset(pOutputIdx);
+  }
+
+  return rc;
+}
+
+/*
+** Allocate an appendable output segment on absolute level iAbsLevel+1
+** with idx value iIdx.
+**
+** In the %_segdir table, a segment is defined by the values in three
+** columns:
+**
+**     start_block
+**     leaves_end_block
+**     end_block
+**
+** When an appendable segment is allocated, it is estimated that the
+** maximum number of leaf blocks that may be required is the sum of the
+** number of leaf blocks consumed by the input segments, plus the number
+** of input segments, multiplied by two. This value is stored in stack
+** variable nLeafEst.
+**
+** A total of 16*nLeafEst blocks are allocated when an appendable segment
+** is created ((1 + end_block - start_block)==16*nLeafEst). The contiguous
+** array of leaf nodes starts at the first block allocated. The array
+** of interior nodes that are parents of the leaf nodes start at block
+** (start_block + (1 + end_block - start_block) / 16). And so on.
+**
+** In the actual code below, the value "16" is replaced with the
+** pre-processor macro FTS_MAX_APPENDABLE_HEIGHT.
+*/
+static int fts3IncrmergeWriter(
+  Fts3Table *p,                   /* Fts3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level of input segments */
+  int iIdx,                       /* Index of new output segment */
+  Fts3MultiSegReader *pCsr,       /* Cursor that data will be read from */
+  IncrmergeWriter *pWriter        /* Populate this object */
+){
+  int rc;                         /* Return Code */
+  int i;                          /* Iterator variable */
+  int nLeafEst = 0;               /* Blocks allocated for leaf nodes */
+  sqlite3_stmt *pLeafEst = 0;     /* SQL used to determine nLeafEst */
+  sqlite3_stmt *pFirstBlock = 0;  /* SQL used to determine first block */
+
+  /* Calculate nLeafEst. */
+  rc = fts3SqlStmt(p, SQL_MAX_LEAF_NODE_ESTIMATE, &pLeafEst, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pLeafEst, 1, iAbsLevel);
+    sqlite3_bind_int64(pLeafEst, 2, pCsr->nSegment);
+    if( SQLITE_ROW==sqlite3_step(pLeafEst) ){
+      nLeafEst = sqlite3_column_int(pLeafEst, 0);
+    }
+    rc = sqlite3_reset(pLeafEst);
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Calculate the first block to use in the output segment */
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pFirstBlock, 0);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pFirstBlock) ){
+      pWriter->iStart = sqlite3_column_int64(pFirstBlock, 0);
+      pWriter->iEnd = pWriter->iStart - 1;
+      pWriter->iEnd += nLeafEst * FTS_MAX_APPENDABLE_HEIGHT;
+    }
+    rc = sqlite3_reset(pFirstBlock);
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Insert the marker in the %_segments table to make sure nobody tries
+  ** to steal the space just allocated. This is also used to identify
+  ** appendable segments.  */
+  rc = fts3WriteSegment(p, pWriter->iEnd, 0, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  pWriter->iAbsLevel = iAbsLevel;
+  pWriter->nLeafEst = nLeafEst;
+  pWriter->iIdx = iIdx;
+
+  /* Set up the array of NodeWriter objects */
+  for(i=0; i<FTS_MAX_APPENDABLE_HEIGHT; i++){
+    pWriter->aNodeWriter[i].iBlock = pWriter->iStart + i*pWriter->nLeafEst;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Remove an entry from the %_segdir table. This involves running the
+** following two statements:
+**
+**   DELETE FROM %_segdir WHERE level = :iAbsLevel AND idx = :iIdx
+**   UPDATE %_segdir SET idx = idx - 1 WHERE level = :iAbsLevel AND idx > :iIdx
+**
+** The DELETE statement removes the specific %_segdir level. The UPDATE
+** statement ensures that the remaining segments have contiguously allocated
+** idx values.
+*/
+static int fts3RemoveSegdirEntry(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level to delete from */
+  int iIdx                        /* Index of %_segdir entry to delete */
+){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pDelete = 0;      /* DELETE statement */
+
+  rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_ENTRY, &pDelete, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pDelete, 1, iAbsLevel);
+    sqlite3_bind_int(pDelete, 2, iIdx);
+    sqlite3_step(pDelete);
+    rc = sqlite3_reset(pDelete);
+  }
+
+  return rc;
+}
+
+/*
+** One or more segments have just been removed from absolute level iAbsLevel.
+** Update the 'idx' values of the remaining segments in the level so that
+** the idx values are a contiguous sequence starting from 0.
+*/
+static int fts3RepackSegdirLevel(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel         /* Absolute level to repack */
+){
+  int rc;                         /* Return code */
+  int *aIdx = 0;                  /* Array of remaining idx values */
+  int nIdx = 0;                   /* Valid entries in aIdx[] */
+  int nAlloc = 0;                 /* Allocated size of aIdx[] */
+  int i;                          /* Iterator variable */
+  sqlite3_stmt *pSelect = 0;      /* Select statement to read idx values */
+  sqlite3_stmt *pUpdate = 0;      /* Update statement to modify idx values */
+
+  rc = fts3SqlStmt(p, SQL_SELECT_INDEXES, &pSelect, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int64(pSelect, 1, iAbsLevel);
+    while( SQLITE_ROW==sqlite3_step(pSelect) ){
+      if( nIdx>=nAlloc ){
+        int *aNew;
+        nAlloc += 16;
+        aNew = sqlite3_realloc64(aIdx, nAlloc*sizeof(int));
+        if( !aNew ){
+          rc = SQLITE_NOMEM;
+          break;
+        }
+        aIdx = aNew;
+      }
+      aIdx[nIdx++] = sqlite3_column_int(pSelect, 0);
+    }
+    rc2 = sqlite3_reset(pSelect);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts3SqlStmt(p, SQL_SHIFT_SEGDIR_ENTRY, &pUpdate, 0);
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pUpdate, 2, iAbsLevel);
+  }
+
+  assert( p->bIgnoreSavepoint==0 );
+  p->bIgnoreSavepoint = 1;
+  for(i=0; rc==SQLITE_OK && i<nIdx; i++){
+    if( aIdx[i]!=i ){
+      sqlite3_bind_int(pUpdate, 3, aIdx[i]);
+      sqlite3_bind_int(pUpdate, 1, i);
+      sqlite3_step(pUpdate);
+      rc = sqlite3_reset(pUpdate);
+    }
+  }
+  p->bIgnoreSavepoint = 0;
+
+  sqlite3_free(aIdx);
+  return rc;
+}
+
+static void fts3StartNode(Blob *pNode, int iHeight, sqlite3_int64 iChild){
+  pNode->a[0] = (char)iHeight;
+  if( iChild ){
+    assert( pNode->nAlloc>=1+sqlite3Fts3VarintLen(iChild) );
+    pNode->n = 1 + sqlite3Fts3PutVarint(&pNode->a[1], iChild);
+  }else{
+    assert( pNode->nAlloc>=1 );
+    pNode->n = 1;
+  }
+}
+
+/*
+** The first two arguments are a pointer to and the size of a segment b-tree
+** node. The node may be a leaf or an internal node.
+**
+** This function creates a new node image in blob object *pNew by copying
+** all terms that are greater than or equal to zTerm/nTerm (for leaf nodes)
+** or greater than zTerm/nTerm (for internal nodes) from aNode/nNode.
+*/
+static int fts3TruncateNode(
+  const char *aNode,              /* Current node image */
+  int nNode,                      /* Size of aNode in bytes */
+  Blob *pNew,                     /* OUT: Write new node image here */
+  const char *zTerm,              /* Omit all terms smaller than this */
+  int nTerm,                      /* Size of zTerm in bytes */
+  sqlite3_int64 *piBlock          /* OUT: Block number in next layer down */
+){
+  NodeReader reader;              /* Reader object */
+  Blob prev = {0, 0, 0};          /* Previous term written to new node */
+  int rc = SQLITE_OK;             /* Return code */
+  int bLeaf;                       /* True for a leaf node */
+
+  if( nNode<1 ) return FTS_CORRUPT_VTAB;
+  bLeaf = aNode[0]=='\0';
+
+  /* Allocate required output space */
+  blobGrowBuffer(pNew, nNode, &rc);
+  if( rc!=SQLITE_OK ) return rc;
+  pNew->n = 0;
+
+  /* Populate new node buffer */
+  for(rc = nodeReaderInit(&reader, aNode, nNode);
+      rc==SQLITE_OK && reader.aNode;
+      rc = nodeReaderNext(&reader)
+  ){
+    if( pNew->n==0 ){
+      int res = fts3TermCmp(reader.term.a, reader.term.n, zTerm, nTerm);
+      if( res<0 || (bLeaf==0 && res==0) ) continue;
+      fts3StartNode(pNew, (int)aNode[0], reader.iChild);
+      *piBlock = reader.iChild;
+    }
+    rc = fts3AppendToNode(
+        pNew, &prev, reader.term.a, reader.term.n,
+        reader.aDoclist, reader.nDoclist
+    );
+    if( rc!=SQLITE_OK ) break;
+  }
+  if( pNew->n==0 ){
+    fts3StartNode(pNew, (int)aNode[0], reader.iChild);
+    *piBlock = reader.iChild;
+  }
+  assert( pNew->n<=pNew->nAlloc );
+
+  nodeReaderRelease(&reader);
+  sqlite3_free(prev.a);
+  return rc;
+}
+
+/*
+** Remove all terms smaller than zTerm/nTerm from segment iIdx in absolute
+** level iAbsLevel. This may involve deleting entries from the %_segments
+** table, and modifying existing entries in both the %_segments and %_segdir
+** tables.
+**
+** SQLITE_OK is returned if the segment is updated successfully. Or an
+** SQLite error code otherwise.
+*/
+static int fts3TruncateSegment(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level of segment to modify */
+  int iIdx,                       /* Index within level of segment to modify */
+  const char *zTerm,              /* Remove terms smaller than this */
+  int nTerm                      /* Number of bytes in buffer zTerm */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Blob root = {0,0,0};            /* New root page image */
+  Blob block = {0,0,0};           /* Buffer used for any other block */
+  sqlite3_int64 iBlock = 0;       /* Block id */
+  sqlite3_int64 iNewStart = 0;    /* New value for iStartBlock */
+  sqlite3_int64 iOldStart = 0;    /* Old value for iStartBlock */
+  sqlite3_stmt *pFetch = 0;       /* Statement used to fetch segdir */
+
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR, &pFetch, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;                      /* sqlite3_reset() return code */
+    sqlite3_bind_int64(pFetch, 1, iAbsLevel);
+    sqlite3_bind_int(pFetch, 2, iIdx);
+    if( SQLITE_ROW==sqlite3_step(pFetch) ){
+      const char *aRoot = sqlite3_column_blob(pFetch, 4);
+      int nRoot = sqlite3_column_bytes(pFetch, 4);
+      iOldStart = sqlite3_column_int64(pFetch, 1);
+      rc = fts3TruncateNode(aRoot, nRoot, &root, zTerm, nTerm, &iBlock);
+    }
+    rc2 = sqlite3_reset(pFetch);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  while( rc==SQLITE_OK && iBlock ){
+    char *aBlock = 0;
+    int nBlock = 0;
+    iNewStart = iBlock;
+
+    rc = sqlite3Fts3ReadBlock(p, iBlock, &aBlock, &nBlock, 0);
+    if( rc==SQLITE_OK ){
+      rc = fts3TruncateNode(aBlock, nBlock, &block, zTerm, nTerm, &iBlock);
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3WriteSegment(p, iNewStart, block.a, block.n);
+    }
+    sqlite3_free(aBlock);
+  }
+
+  /* Variable iNewStart now contains the first valid leaf node. */
+  if( rc==SQLITE_OK && iNewStart ){
+    sqlite3_stmt *pDel = 0;
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDel, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDel, 1, iOldStart);
+      sqlite3_bind_int64(pDel, 2, iNewStart-1);
+      sqlite3_step(pDel);
+      rc = sqlite3_reset(pDel);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sqlite3_stmt *pChomp = 0;
+    rc = fts3SqlStmt(p, SQL_CHOMP_SEGDIR, &pChomp, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pChomp, 1, iNewStart);
+      sqlite3_bind_blob(pChomp, 2, root.a, root.n, SQLITE_STATIC);
+      sqlite3_bind_int64(pChomp, 3, iAbsLevel);
+      sqlite3_bind_int(pChomp, 4, iIdx);
+      sqlite3_step(pChomp);
+      rc = sqlite3_reset(pChomp);
+      sqlite3_bind_null(pChomp, 2);
+    }
+  }
+
+  sqlite3_free(root.a);
+  sqlite3_free(block.a);
+  return rc;
+}
+
+/*
+** This function is called after an incrmental-merge operation has run to
+** merge (or partially merge) two or more segments from absolute level
+** iAbsLevel.
+**
+** Each input segment is either removed from the db completely (if all of
+** its data was copied to the output segment by the incrmerge operation)
+** or modified in place so that it no longer contains those entries that
+** have been duplicated in the output segment.
+*/
+static int fts3IncrmergeChomp(
+  Fts3Table *p,                   /* FTS table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level containing segments */
+  Fts3MultiSegReader *pCsr,       /* Chomp all segments opened by this cursor */
+  int *pnRem                      /* Number of segments not deleted */
+){
+  int i;
+  int nRem = 0;
+  int rc = SQLITE_OK;
+
+  for(i=pCsr->nSegment-1; i>=0 && rc==SQLITE_OK; i--){
+    Fts3SegReader *pSeg = 0;
+    int j;
+
+    /* Find the Fts3SegReader object with Fts3SegReader.iIdx==i. It is hiding
+    ** somewhere in the pCsr->apSegment[] array.  */
+    for(j=0; ALWAYS(j<pCsr->nSegment); j++){
+      pSeg = pCsr->apSegment[j];
+      if( pSeg->iIdx==i ) break;
+    }
+    assert( j<pCsr->nSegment && pSeg->iIdx==i );
+
+    if( pSeg->aNode==0 ){
+      /* Seg-reader is at EOF. Remove the entire input segment. */
+      rc = fts3DeleteSegment(p, pSeg);
+      if( rc==SQLITE_OK ){
+        rc = fts3RemoveSegdirEntry(p, iAbsLevel, pSeg->iIdx);
+      }
+      *pnRem = 0;
+    }else{
+      /* The incremental merge did not copy all the data from this
+      ** segment to the upper level. The segment is modified in place
+      ** so that it contains no keys smaller than zTerm/nTerm. */
+      const char *zTerm = pSeg->zTerm;
+      int nTerm = pSeg->nTerm;
+      rc = fts3TruncateSegment(p, iAbsLevel, pSeg->iIdx, zTerm, nTerm);
+      nRem++;
+    }
+  }
+
+  if( rc==SQLITE_OK && nRem!=pCsr->nSegment ){
+    rc = fts3RepackSegdirLevel(p, iAbsLevel);
+  }
+
+  *pnRem = nRem;
+  return rc;
+}
+
+/*
+** Store an incr-merge hint in the database.
+*/
+static int fts3IncrmergeHintStore(Fts3Table *p, Blob *pHint){
+  sqlite3_stmt *pReplace = 0;
+  int rc;                         /* Return code */
+
+  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pReplace, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int(pReplace, 1, FTS_STAT_INCRMERGEHINT);
+    sqlite3_bind_blob(pReplace, 2, pHint->a, pHint->n, SQLITE_STATIC);
+    sqlite3_step(pReplace);
+    rc = sqlite3_reset(pReplace);
+    sqlite3_bind_null(pReplace, 2);
+  }
+
+  return rc;
+}
+
+/*
+** Load an incr-merge hint from the database. The incr-merge hint, if one
+** exists, is stored in the rowid==1 row of the %_stat table.
+**
+** If successful, populate blob *pHint with the value read from the %_stat
+** table and return SQLITE_OK. Otherwise, if an error occurs, return an
+** SQLite error code.
+*/
+static int fts3IncrmergeHintLoad(Fts3Table *p, Blob *pHint){
+  sqlite3_stmt *pSelect = 0;
+  int rc;
+
+  pHint->n = 0;
+  rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pSelect, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int(pSelect, 1, FTS_STAT_INCRMERGEHINT);
+    if( SQLITE_ROW==sqlite3_step(pSelect) ){
+      const char *aHint = sqlite3_column_blob(pSelect, 0);
+      int nHint = sqlite3_column_bytes(pSelect, 0);
+      if( aHint ){
+        blobGrowBuffer(pHint, nHint, &rc);
+        if( rc==SQLITE_OK ){
+          if( ALWAYS(pHint->a!=0) ) memcpy(pHint->a, aHint, nHint);
+          pHint->n = nHint;
+        }
+      }
+    }
+    rc2 = sqlite3_reset(pSelect);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  return rc;
+}
+
+/*
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, append an entry to the hint stored in blob *pHint. Each entry
+** consists of two varints, the absolute level number of the input segments
+** and the number of input segments.
+**
+** If successful, leave *pRc set to SQLITE_OK and return. If an error occurs,
+** set *pRc to an SQLite error code before returning.
+*/
+static void fts3IncrmergeHintPush(
+  Blob *pHint,                    /* Hint blob to append to */
+  i64 iAbsLevel,                  /* First varint to store in hint */
+  int nInput,                     /* Second varint to store in hint */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  blobGrowBuffer(pHint, pHint->n + 2*FTS3_VARINT_MAX, pRc);
+  if( *pRc==SQLITE_OK ){
+    pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], iAbsLevel);
+    pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], (i64)nInput);
+  }
+}
+
+/*
+** Read the last entry (most recently pushed) from the hint blob *pHint
+** and then remove the entry. Write the two values read to *piAbsLevel and
+** *pnInput before returning.
+**
+** If no error occurs, return SQLITE_OK. If the hint blob in *pHint does
+** not contain at least two valid varints, return SQLITE_CORRUPT_VTAB.
+*/
+static int fts3IncrmergeHintPop(Blob *pHint, i64 *piAbsLevel, int *pnInput){
+  const int nHint = pHint->n;
+  int i;
+
+  i = pHint->n-1;
+  if( (pHint->a[i] & 0x80) ) return FTS_CORRUPT_VTAB;
+  while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
+  if( i==0 ) return FTS_CORRUPT_VTAB;
+  i--;
+  while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
+
+  pHint->n = i;
+  i += sqlite3Fts3GetVarint(&pHint->a[i], piAbsLevel);
+  i += fts3GetVarint32(&pHint->a[i], pnInput);
+  assert( i<=nHint );
+  if( i!=nHint ) return FTS_CORRUPT_VTAB;
+
+  return SQLITE_OK;
+}
+
+
+/*
+** Attempt an incremental merge that writes nMerge leaf blocks.
+**
+** Incremental merges happen nMin segments at a time. The segments
+** to be merged are the nMin oldest segments (the ones with the smallest
+** values for the _segdir.idx field) in the highest level that contains
+** at least nMin segments. Multiple merges might occur in an attempt to
+** write the quota of nMerge leaf blocks.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Incrmerge(Fts3Table *p, int nMerge, int nMin){
+  int rc;                         /* Return code */
+  int nRem = nMerge;              /* Number of leaf pages yet to  be written */
+  Fts3MultiSegReader *pCsr;       /* Cursor used to read input data */
+  Fts3SegFilter *pFilter;         /* Filter used with cursor pCsr */
+  IncrmergeWriter *pWriter;       /* Writer object */
+  int nSeg = 0;                   /* Number of input segments */
+  sqlite3_int64 iAbsLevel = 0;    /* Absolute level number to work on */
+  Blob hint = {0, 0, 0};          /* Hint read from %_stat table */
+  int bDirtyHint = 0;             /* True if blob 'hint' has been modified */
+
+  /* Allocate space for the cursor, filter and writer objects */
+  const int nAlloc = sizeof(*pCsr) + sizeof(*pFilter) + sizeof(*pWriter);
+  pWriter = (IncrmergeWriter *)sqlite3_malloc64(nAlloc);
+  if( !pWriter ) return SQLITE_NOMEM;
+  pFilter = (Fts3SegFilter *)&pWriter[1];
+  pCsr = (Fts3MultiSegReader *)&pFilter[1];
+
+  rc = fts3IncrmergeHintLoad(p, &hint);
+  while( rc==SQLITE_OK && nRem>0 ){
+    const i64 nMod = FTS3_SEGDIR_MAXLEVEL * p->nIndex;
+    sqlite3_stmt *pFindLevel = 0; /* SQL used to determine iAbsLevel */
+    int bUseHint = 0;             /* True if attempting to append */
+    int iIdx = 0;                 /* Largest idx in level (iAbsLevel+1) */
+
+    /* Search the %_segdir table for the absolute level with the smallest
+    ** relative level number that contains at least nMin segments, if any.
+    ** If one is found, set iAbsLevel to the absolute level number and
+    ** nSeg to nMin. If no level with at least nMin segments can be found,
+    ** set nSeg to -1.
+    */
+    rc = fts3SqlStmt(p, SQL_FIND_MERGE_LEVEL, &pFindLevel, 0);
+    sqlite3_bind_int(pFindLevel, 1, MAX(2, nMin));
+    if( sqlite3_step(pFindLevel)==SQLITE_ROW ){
+      iAbsLevel = sqlite3_column_int64(pFindLevel, 0);
+      nSeg = sqlite3_column_int(pFindLevel, 1);
+      assert( nSeg>=2 );
+    }else{
+      nSeg = -1;
+    }
+    rc = sqlite3_reset(pFindLevel);
+
+    /* If the hint read from the %_stat table is not empty, check if the
+    ** last entry in it specifies a relative level smaller than or equal
+    ** to the level identified by the block above (if any). If so, this
+    ** iteration of the loop will work on merging at the hinted level.
+    */
+    if( rc==SQLITE_OK && hint.n ){
+      int nHint = hint.n;
+      sqlite3_int64 iHintAbsLevel = 0;      /* Hint level */
+      int nHintSeg = 0;                     /* Hint number of segments */
+
+      rc = fts3IncrmergeHintPop(&hint, &iHintAbsLevel, &nHintSeg);
+      if( nSeg<0 || (iAbsLevel % nMod) >= (iHintAbsLevel % nMod) ){
+        /* Based on the scan in the block above, it is known that there
+        ** are no levels with a relative level smaller than that of
+        ** iAbsLevel with more than nSeg segments, or if nSeg is -1,
+        ** no levels with more than nMin segments. Use this to limit the
+        ** value of nHintSeg to avoid a large memory allocation in case the
+        ** merge-hint is corrupt*/
+        iAbsLevel = iHintAbsLevel;
+        nSeg = MIN(MAX(nMin,nSeg), nHintSeg);
+        bUseHint = 1;
+        bDirtyHint = 1;
+      }else{
+        /* This undoes the effect of the HintPop() above - so that no entry
+        ** is removed from the hint blob.  */
+        hint.n = nHint;
+      }
+    }
+
+    /* If nSeg is less that zero, then there is no level with at least
+    ** nMin segments and no hint in the %_stat table. No work to do.
+    ** Exit early in this case.  */
+    if( nSeg<=0 ) break;
+
+    assert( nMod<=0x7FFFFFFF );
+    if( iAbsLevel<0 || iAbsLevel>(nMod<<32) ){
+      rc = FTS_CORRUPT_VTAB;
+      break;
+    }
+
+    /* Open a cursor to iterate through the contents of the oldest nSeg
+    ** indexes of absolute level iAbsLevel. If this cursor is opened using
+    ** the 'hint' parameters, it is possible that there are less than nSeg
+    ** segments available in level iAbsLevel. In this case, no work is
+    ** done on iAbsLevel - fall through to the next iteration of the loop
+    ** to start work on some other level.  */
+    memset(pWriter, 0, nAlloc);
+    pFilter->flags = FTS3_SEGMENT_REQUIRE_POS;
+
+    if( rc==SQLITE_OK ){
+      rc = fts3IncrmergeOutputIdx(p, iAbsLevel, &iIdx);
+      assert( bUseHint==1 || bUseHint==0 );
+      if( iIdx==0 || (bUseHint && iIdx==1) ){
+        int bIgnore = 0;
+        rc = fts3SegmentIsMaxLevel(p, iAbsLevel+1, &bIgnore);
+        if( bIgnore ){
+          pFilter->flags |= FTS3_SEGMENT_IGNORE_EMPTY;
+        }
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = fts3IncrmergeCsr(p, iAbsLevel, nSeg, pCsr);
+    }
+    if( SQLITE_OK==rc && pCsr->nSegment==nSeg
+     && SQLITE_OK==(rc = sqlite3Fts3SegReaderStart(p, pCsr, pFilter))
+    ){
+      int bEmpty = 0;
+      rc = sqlite3Fts3SegReaderStep(p, pCsr);
+      if( rc==SQLITE_OK ){
+        bEmpty = 1;
+      }else if( rc!=SQLITE_ROW ){
+        sqlite3Fts3SegReaderFinish(pCsr);
+        break;
+      }
+      if( bUseHint && iIdx>0 ){
+        const char *zKey = pCsr->zTerm;
+        int nKey = pCsr->nTerm;
+        rc = fts3IncrmergeLoad(p, iAbsLevel, iIdx-1, zKey, nKey, pWriter);
+      }else{
+        rc = fts3IncrmergeWriter(p, iAbsLevel, iIdx, pCsr, pWriter);
+      }
+
+      if( rc==SQLITE_OK && pWriter->nLeafEst ){
+        fts3LogMerge(nSeg, iAbsLevel);
+        if( bEmpty==0 ){
+          do {
+            rc = fts3IncrmergeAppend(p, pWriter, pCsr);
+            if( rc==SQLITE_OK ) rc = sqlite3Fts3SegReaderStep(p, pCsr);
+            if( pWriter->nWork>=nRem && rc==SQLITE_ROW ) rc = SQLITE_OK;
+          }while( rc==SQLITE_ROW );
+        }
+
+        /* Update or delete the input segments */
+        if( rc==SQLITE_OK ){
+          nRem -= (1 + pWriter->nWork);
+          rc = fts3IncrmergeChomp(p, iAbsLevel, pCsr, &nSeg);
+          if( nSeg!=0 ){
+            bDirtyHint = 1;
+            fts3IncrmergeHintPush(&hint, iAbsLevel, nSeg, &rc);
+          }
+        }
+      }
+
+      if( nSeg!=0 ){
+        pWriter->nLeafData = pWriter->nLeafData * -1;
+      }
+      fts3IncrmergeRelease(p, pWriter, &rc);
+      if( nSeg==0 && pWriter->bNoLeafData==0 ){
+        fts3PromoteSegments(p, iAbsLevel+1, pWriter->nLeafData);
+      }
+    }
+
+    sqlite3Fts3SegReaderFinish(pCsr);
+  }
+
+  /* Write the hint values into the %_stat table for the next incr-merger */
+  if( bDirtyHint && rc==SQLITE_OK ){
+    rc = fts3IncrmergeHintStore(p, &hint);
+  }
+
+  sqlite3_free(pWriter);
+  sqlite3_free(hint.a);
+  return rc;
+}
+
+/*
+** Convert the text beginning at *pz into an integer and return
+** its value.  Advance *pz to point to the first character past
+** the integer.
+**
+** This function used for parameters to merge= and incrmerge=
+** commands.
+*/
+static int fts3Getint(const char **pz){
+  const char *z = *pz;
+  int i = 0;
+  while( (*z)>='0' && (*z)<='9' && i<214748363 ) i = 10*i + *(z++) - '0';
+  *pz = z;
+  return i;
+}
+
+/*
+** Process statements of the form:
+**
+**    INSERT INTO table(table) VALUES('merge=A,B');
+**
+** A and B are integers that decode to be the number of leaf pages
+** written for the merge, and the minimum number of segments on a level
+** before it will be selected for a merge, respectively.
+*/
+static int fts3DoIncrmerge(
+  Fts3Table *p,                   /* FTS3 table handle */
+  const char *zParam              /* Nul-terminated string containing "A,B" */
+){
+  int rc;
+  int nMin = (MergeCount(p) / 2);
+  int nMerge = 0;
+  const char *z = zParam;
+
+  /* Read the first integer value */
+  nMerge = fts3Getint(&z);
+
+  /* If the first integer value is followed by a ',',  read the second
+  ** integer value. */
+  if( z[0]==',' && z[1]!='\0' ){
+    z++;
+    nMin = fts3Getint(&z);
+  }
+
+  if( z[0]!='\0' || nMin<2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    rc = SQLITE_OK;
+    if( !p->bHasStat ){
+      assert( p->bFts4==0 );
+      sqlite3Fts3CreateStatTable(&rc, p);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts3Incrmerge(p, nMerge, nMin);
+    }
+    sqlite3Fts3SegmentsClose(p);
+  }
+  return rc;
+}
+
+/*
+** Process statements of the form:
+**
+**    INSERT INTO table(table) VALUES('automerge=X');
+**
+** where X is an integer.  X==0 means to turn automerge off.  X!=0 means
+** turn it on.  The setting is persistent.
+*/
+static int fts3DoAutoincrmerge(
+  Fts3Table *p,                   /* FTS3 table handle */
+  const char *zParam              /* Nul-terminated string containing boolean */
+){
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pStmt = 0;
+  p->nAutoincrmerge = fts3Getint(&zParam);
+  if( p->nAutoincrmerge==1 || p->nAutoincrmerge>MergeCount(p) ){
+    p->nAutoincrmerge = 8;
+  }
+  if( !p->bHasStat ){
+    assert( p->bFts4==0 );
+    sqlite3Fts3CreateStatTable(&rc, p);
+    if( rc ) return rc;
+  }
+  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pStmt, 0);
+  if( rc ) return rc;
+  sqlite3_bind_int(pStmt, 1, FTS_STAT_AUTOINCRMERGE);
+  sqlite3_bind_int(pStmt, 2, p->nAutoincrmerge);
+  sqlite3_step(pStmt);
+  rc = sqlite3_reset(pStmt);
+  return rc;
+}
+
+/*
+** Return a 64-bit checksum for the FTS index entry specified by the
+** arguments to this function.
+*/
+static u64 fts3ChecksumEntry(
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int iLangid,                    /* Language id for current row */
+  int iIndex,                     /* Index (0..Fts3Table.nIndex-1) */
+  i64 iDocid,                     /* Docid for current row. */
+  int iCol,                       /* Column number */
+  int iPos                        /* Position */
+){
+  int i;
+  u64 ret = (u64)iDocid;
+
+  ret += (ret<<3) + iLangid;
+  ret += (ret<<3) + iIndex;
+  ret += (ret<<3) + iCol;
+  ret += (ret<<3) + iPos;
+  for(i=0; i<nTerm; i++) ret += (ret<<3) + zTerm[i];
+
+  return ret;
+}
+
+/*
+** Return a checksum of all entries in the FTS index that correspond to
+** language id iLangid. The checksum is calculated by XORing the checksums
+** of each individual entry (see fts3ChecksumEntry()) together.
+**
+** If successful, the checksum value is returned and *pRc set to SQLITE_OK.
+** Otherwise, if an error occurs, *pRc is set to an SQLite error code. The
+** return value is undefined in this case.
+*/
+static u64 fts3ChecksumIndex(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language id to return cksum for */
+  int iIndex,                     /* Index to cksum (0..p->nIndex-1) */
+  int *pRc                        /* OUT: Return code */
+){
+  Fts3SegFilter filter;
+  Fts3MultiSegReader csr;
+  int rc;
+  u64 cksum = 0;
+
+  if( *pRc ) return 0;
+
+  memset(&filter, 0, sizeof(filter));
+  memset(&csr, 0, sizeof(csr));
+  filter.flags =  FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
+  filter.flags |= FTS3_SEGMENT_SCAN;
+
+  rc = sqlite3Fts3SegReaderCursor(
+      p, iLangid, iIndex, FTS3_SEGCURSOR_ALL, 0, 0, 0, 1,&csr
+  );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
+  }
+
+  if( rc==SQLITE_OK ){
+    while( SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, &csr)) ){
+      char *pCsr = csr.aDoclist;
+      char *pEnd = &pCsr[csr.nDoclist];
+
+      i64 iDocid = 0;
+      i64 iCol = 0;
+      u64 iPos = 0;
+
+      pCsr += sqlite3Fts3GetVarint(pCsr, &iDocid);
+      while( pCsr<pEnd ){
+        u64 iVal = 0;
+        pCsr += sqlite3Fts3GetVarintU(pCsr, &iVal);
+        if( pCsr<pEnd ){
+          if( iVal==0 || iVal==1 ){
+            iCol = 0;
+            iPos = 0;
+            if( iVal ){
+              pCsr += sqlite3Fts3GetVarint(pCsr, &iCol);
+            }else{
+              pCsr += sqlite3Fts3GetVarintU(pCsr, &iVal);
+              if( p->bDescIdx ){
+                iDocid = (i64)((u64)iDocid - iVal);
+              }else{
+                iDocid = (i64)((u64)iDocid + iVal);
+              }
+            }
+          }else{
+            iPos += (iVal - 2);
+            cksum = cksum ^ fts3ChecksumEntry(
+                csr.zTerm, csr.nTerm, iLangid, iIndex, iDocid,
+                (int)iCol, (int)iPos
+            );
+          }
+        }
+      }
+    }
+  }
+  sqlite3Fts3SegReaderFinish(&csr);
+
+  *pRc = rc;
+  return cksum;
+}
+
+/*
+** Check if the contents of the FTS index match the current contents of the
+** content table. If no error occurs and the contents do match, set *pbOk
+** to true and return SQLITE_OK. Or if the contents do not match, set *pbOk
+** to false before returning.
+**
+** If an error occurs (e.g. an OOM or IO error), return an SQLite error
+** code. The final value of *pbOk is undefined in this case.
+*/
+SQLITE_PRIVATE int sqlite3Fts3IntegrityCheck(Fts3Table *p, int *pbOk){
+  int rc = SQLITE_OK;             /* Return code */
+  u64 cksum1 = 0;                 /* Checksum based on FTS index contents */
+  u64 cksum2 = 0;                 /* Checksum based on %_content contents */
+  sqlite3_stmt *pAllLangid = 0;   /* Statement to return all language-ids */
+
+  /* This block calculates the checksum according to the FTS index. */
+  rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int(pAllLangid, 1, p->iPrevLangid);
+    sqlite3_bind_int(pAllLangid, 2, p->nIndex);
+    while( rc==SQLITE_OK && sqlite3_step(pAllLangid)==SQLITE_ROW ){
+      int iLangid = sqlite3_column_int(pAllLangid, 0);
+      int i;
+      for(i=0; i<p->nIndex; i++){
+        cksum1 = cksum1 ^ fts3ChecksumIndex(p, iLangid, i, &rc);
+      }
+    }
+    rc2 = sqlite3_reset(pAllLangid);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  /* This block calculates the checksum according to the %_content table */
+  if( rc==SQLITE_OK ){
+    sqlite3_tokenizer_module const *pModule = p->pTokenizer->pModule;
+    sqlite3_stmt *pStmt = 0;
+    char *zSql;
+
+    zSql = sqlite3_mprintf("SELECT %s" , p->zReadExprlist);
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
+      sqlite3_free(zSql);
+    }
+
+    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      i64 iDocid = sqlite3_column_int64(pStmt, 0);
+      int iLang = langidFromSelect(p, pStmt);
+      int iCol;
+
+      for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
+        if( p->abNotindexed[iCol]==0 ){
+          const char *zText = (const char *)sqlite3_column_text(pStmt, iCol+1);
+          sqlite3_tokenizer_cursor *pT = 0;
+
+          rc = sqlite3Fts3OpenTokenizer(p->pTokenizer, iLang, zText, -1, &pT);
+          while( rc==SQLITE_OK ){
+            char const *zToken;       /* Buffer containing token */
+            int nToken = 0;           /* Number of bytes in token */
+            int iDum1 = 0, iDum2 = 0; /* Dummy variables */
+            int iPos = 0;             /* Position of token in zText */
+
+            rc = pModule->xNext(pT, &zToken, &nToken, &iDum1, &iDum2, &iPos);
+            if( rc==SQLITE_OK ){
+              int i;
+              cksum2 = cksum2 ^ fts3ChecksumEntry(
+                  zToken, nToken, iLang, 0, iDocid, iCol, iPos
+              );
+              for(i=1; i<p->nIndex; i++){
+                if( p->aIndex[i].nPrefix<=nToken ){
+                  cksum2 = cksum2 ^ fts3ChecksumEntry(
+                      zToken, p->aIndex[i].nPrefix, iLang, i, iDocid, iCol, iPos
+                  );
+                }
+              }
+            }
+          }
+          if( pT ) pModule->xClose(pT);
+          if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+        }
+      }
+    }
+
+    sqlite3_finalize(pStmt);
+  }
+
+  if( rc==SQLITE_CORRUPT_VTAB ){
+    rc = SQLITE_OK;
+    *pbOk = 0;
+  }else{
+    *pbOk = (rc==SQLITE_OK && cksum1==cksum2);
+  }
+  return rc;
+}
+
+/*
+** Run the integrity-check. If no error occurs and the current contents of
+** the FTS index are correct, return SQLITE_OK. Or, if the contents of the
+** FTS index are incorrect, return SQLITE_CORRUPT_VTAB.
+**
+** Or, if an error (e.g. an OOM or IO error) occurs, return an SQLite
+** error code.
+**
+** The integrity-check works as follows. For each token and indexed token
+** prefix in the document set, a 64-bit checksum is calculated (by code
+** in fts3ChecksumEntry()) based on the following:
+**
+**     + The index number (0 for the main index, 1 for the first prefix
+**       index etc.),
+**     + The token (or token prefix) text itself,
+**     + The language-id of the row it appears in,
+**     + The docid of the row it appears in,
+**     + The column it appears in, and
+**     + The tokens position within that column.
+**
+** The checksums for all entries in the index are XORed together to create
+** a single checksum for the entire index.
+**
+** The integrity-check code calculates the same checksum in two ways:
+**
+**     1. By scanning the contents of the FTS index, and
+**     2. By scanning and tokenizing the content table.
+**
+** If the two checksums are identical, the integrity-check is deemed to have
+** passed.
+*/
+static int fts3DoIntegrityCheck(
+  Fts3Table *p                    /* FTS3 table handle */
+){
+  int rc;
+  int bOk = 0;
+  rc = sqlite3Fts3IntegrityCheck(p, &bOk);
+  if( rc==SQLITE_OK && bOk==0 ) rc = FTS_CORRUPT_VTAB;
+  return rc;
+}
+
+/*
+** Handle a 'special' INSERT of the form:
+**
+**   "INSERT INTO tbl(tbl) VALUES(<expr>)"
+**
+** Argument pVal contains the result of <expr>. Currently the only
+** meaningful value to insert is the text 'optimize'.
+*/
+static int fts3SpecialInsert(Fts3Table *p, sqlite3_value *pVal){
+  int rc = SQLITE_ERROR;           /* Return Code */
+  const char *zVal = (const char *)sqlite3_value_text(pVal);
+  int nVal = sqlite3_value_bytes(pVal);
+
+  if( !zVal ){
+    return SQLITE_NOMEM;
+  }else if( nVal==8 && 0==sqlite3_strnicmp(zVal, "optimize", 8) ){
+    rc = fts3DoOptimize(p, 0);
+  }else if( nVal==7 && 0==sqlite3_strnicmp(zVal, "rebuild", 7) ){
+    rc = fts3DoRebuild(p);
+  }else if( nVal==15 && 0==sqlite3_strnicmp(zVal, "integrity-check", 15) ){
+    rc = fts3DoIntegrityCheck(p);
+  }else if( nVal>6 && 0==sqlite3_strnicmp(zVal, "merge=", 6) ){
+    rc = fts3DoIncrmerge(p, &zVal[6]);
+  }else if( nVal>10 && 0==sqlite3_strnicmp(zVal, "automerge=", 10) ){
+    rc = fts3DoAutoincrmerge(p, &zVal[10]);
+  }else if( nVal==5 && 0==sqlite3_strnicmp(zVal, "flush", 5) ){
+    rc = sqlite3Fts3PendingTermsFlush(p);
+  }
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  else{
+    int v;
+    if( nVal>9 && 0==sqlite3_strnicmp(zVal, "nodesize=", 9) ){
+      v = atoi(&zVal[9]);
+      if( v>=24 && v<=p->nPgsz-35 ) p->nNodeSize = v;
+      rc = SQLITE_OK;
+    }else if( nVal>11 && 0==sqlite3_strnicmp(zVal, "maxpending=", 9) ){
+      v = atoi(&zVal[11]);
+      if( v>=64 && v<=FTS3_MAX_PENDING_DATA ) p->nMaxPendingData = v;
+      rc = SQLITE_OK;
+    }else if( nVal>21 && 0==sqlite3_strnicmp(zVal,"test-no-incr-doclist=",21) ){
+      p->bNoIncrDoclist = atoi(&zVal[21]);
+      rc = SQLITE_OK;
+    }else if( nVal>11 && 0==sqlite3_strnicmp(zVal,"mergecount=",11) ){
+      v = atoi(&zVal[11]);
+      if( v>=4 && v<=FTS3_MERGE_COUNT && (v&1)==0 ) p->nMergeCount = v;
+      rc = SQLITE_OK;
+    }
+  }
+#endif
+  return rc;
+}
+
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+/*
+** Delete all cached deferred doclists. Deferred doclists are cached
+** (allocated) by the sqlite3Fts3CacheDeferredDoclists() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *pCsr){
+  Fts3DeferredToken *pDef;
+  for(pDef=pCsr->pDeferred; pDef; pDef=pDef->pNext){
+    fts3PendingListDelete(pDef->pList);
+    pDef->pList = 0;
+  }
+}
+
+/*
+** Free all entries in the pCsr->pDeffered list. Entries are added to
+** this list using sqlite3Fts3DeferToken().
+*/
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *pCsr){
+  Fts3DeferredToken *pDef;
+  Fts3DeferredToken *pNext;
+  for(pDef=pCsr->pDeferred; pDef; pDef=pNext){
+    pNext = pDef->pNext;
+    fts3PendingListDelete(pDef->pList);
+    sqlite3_free(pDef);
+  }
+  pCsr->pDeferred = 0;
+}
+
+/*
+** Generate deferred-doclists for all tokens in the pCsr->pDeferred list
+** based on the row that pCsr currently points to.
+**
+** A deferred-doclist is like any other doclist with position information
+** included, except that it only contains entries for a single row of the
+** table, not for all rows.
+*/
+SQLITE_PRIVATE int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;             /* Return code */
+  if( pCsr->pDeferred ){
+    int i;                        /* Used to iterate through table columns */
+    sqlite3_int64 iDocid;         /* Docid of the row pCsr points to */
+    Fts3DeferredToken *pDef;      /* Used to iterate through deferred tokens */
+
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+    sqlite3_tokenizer *pT = p->pTokenizer;
+    sqlite3_tokenizer_module const *pModule = pT->pModule;
+
+    assert( pCsr->isRequireSeek==0 );
+    iDocid = sqlite3_column_int64(pCsr->pStmt, 0);
+
+    for(i=0; i<p->nColumn && rc==SQLITE_OK; i++){
+      if( p->abNotindexed[i]==0 ){
+        const char *zText = (const char *)sqlite3_column_text(pCsr->pStmt, i+1);
+        sqlite3_tokenizer_cursor *pTC = 0;
+
+        rc = sqlite3Fts3OpenTokenizer(pT, pCsr->iLangid, zText, -1, &pTC);
+        while( rc==SQLITE_OK ){
+          char const *zToken;       /* Buffer containing token */
+          int nToken = 0;           /* Number of bytes in token */
+          int iDum1 = 0, iDum2 = 0; /* Dummy variables */
+          int iPos = 0;             /* Position of token in zText */
+
+          rc = pModule->xNext(pTC, &zToken, &nToken, &iDum1, &iDum2, &iPos);
+          for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
+            Fts3PhraseToken *pPT = pDef->pToken;
+            if( (pDef->iCol>=p->nColumn || pDef->iCol==i)
+                && (pPT->bFirst==0 || iPos==0)
+                && (pPT->n==nToken || (pPT->isPrefix && pPT->n<nToken))
+                && (0==memcmp(zToken, pPT->z, pPT->n))
+              ){
+              fts3PendingListAppend(&pDef->pList, iDocid, i, iPos, &rc);
+            }
+          }
+        }
+        if( pTC ) pModule->xClose(pTC);
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+      }
+    }
+
+    for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
+      if( pDef->pList ){
+        rc = fts3PendingListAppendVarint(&pDef->pList, 0);
+      }
+    }
+  }
+
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3DeferredTokenList(
+  Fts3DeferredToken *p,
+  char **ppData,
+  int *pnData
+){
+  char *pRet;
+  int nSkip;
+  sqlite3_int64 dummy;
+
+  *ppData = 0;
+  *pnData = 0;
+
+  if( p->pList==0 ){
+    return SQLITE_OK;
+  }
+
+  pRet = (char *)sqlite3_malloc64(p->pList->nData);
+  if( !pRet ) return SQLITE_NOMEM;
+
+  nSkip = sqlite3Fts3GetVarint(p->pList->aData, &dummy);
+  *pnData = p->pList->nData - nSkip;
+  *ppData = pRet;
+
+  memcpy(pRet, &p->pList->aData[nSkip], *pnData);
+  return SQLITE_OK;
+}
+
+/*
+** Add an entry for token pToken to the pCsr->pDeferred list.
+*/
+SQLITE_PRIVATE int sqlite3Fts3DeferToken(
+  Fts3Cursor *pCsr,               /* Fts3 table cursor */
+  Fts3PhraseToken *pToken,        /* Token to defer */
+  int iCol                        /* Column that token must appear in (or -1) */
+){
+  Fts3DeferredToken *pDeferred;
+  pDeferred = sqlite3_malloc64(sizeof(*pDeferred));
+  if( !pDeferred ){
+    return SQLITE_NOMEM;
+  }
+  memset(pDeferred, 0, sizeof(*pDeferred));
+  pDeferred->pToken = pToken;
+  pDeferred->pNext = pCsr->pDeferred;
+  pDeferred->iCol = iCol;
+  pCsr->pDeferred = pDeferred;
+
+  assert( pToken->pDeferred==0 );
+  pToken->pDeferred = pDeferred;
+
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** SQLite value pRowid contains the rowid of a row that may or may not be
+** present in the FTS3 table. If it is, delete it and adjust the contents
+** of subsiduary data structures accordingly.
+*/
+static int fts3DeleteByRowid(
+  Fts3Table *p,
+  sqlite3_value *pRowid,
+  int *pnChng,                    /* IN/OUT: Decrement if row is deleted */
+  u32 *aSzDel
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int bFound = 0;                 /* True if *pRowid really is in the table */
+
+  fts3DeleteTerms(&rc, p, pRowid, aSzDel, &bFound);
+  if( bFound && rc==SQLITE_OK ){
+    int isEmpty = 0;              /* Deleting *pRowid leaves the table empty */
+    rc = fts3IsEmpty(p, pRowid, &isEmpty);
+    if( rc==SQLITE_OK ){
+      if( isEmpty ){
+        /* Deleting this row means the whole table is empty. In this case
+        ** delete the contents of all three tables and throw away any
+        ** data in the pendingTerms hash table.  */
+        rc = fts3DeleteAll(p, 1);
+        *pnChng = 0;
+        memset(aSzDel, 0, sizeof(u32) * (p->nColumn+1) * 2);
+      }else{
+        *pnChng = *pnChng - 1;
+        if( p->zContentTbl==0 ){
+          fts3SqlExec(&rc, p, SQL_DELETE_CONTENT, &pRowid);
+        }
+        if( p->bHasDocsize ){
+          fts3SqlExec(&rc, p, SQL_DELETE_DOCSIZE, &pRowid);
+        }
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function does the work for the xUpdate method of FTS3 virtual
+** tables. The schema of the virtual table being:
+**
+**     CREATE TABLE <table name>(
+**       <user columns>,
+**       <table name> HIDDEN,
+**       docid HIDDEN,
+**       <langid> HIDDEN
+**     );
+**
+**
+*/
+SQLITE_PRIVATE int sqlite3Fts3UpdateMethod(
+  sqlite3_vtab *pVtab,            /* FTS3 vtab object */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int rc = SQLITE_OK;             /* Return Code */
+  u32 *aSzIns = 0;                /* Sizes of inserted documents */
+  u32 *aSzDel = 0;                /* Sizes of deleted documents */
+  int nChng = 0;                  /* Net change in number of documents */
+  int bInsertDone = 0;
+
+  /* At this point it must be known if the %_stat table exists or not.
+  ** So bHasStat may not be 2.  */
+  assert( p->bHasStat==0 || p->bHasStat==1 );
+
+  assert( p->pSegments==0 );
+  assert(
+      nArg==1                     /* DELETE operations */
+   || nArg==(2 + p->nColumn + 3)  /* INSERT or UPDATE operations */
+  );
+
+  /* Check for a "special" INSERT operation. One of the form:
+  **
+  **   INSERT INTO xyz(xyz) VALUES('command');
+  */
+  if( nArg>1
+   && sqlite3_value_type(apVal[0])==SQLITE_NULL
+   && sqlite3_value_type(apVal[p->nColumn+2])!=SQLITE_NULL
+  ){
+    rc = fts3SpecialInsert(p, apVal[p->nColumn+2]);
+    goto update_out;
+  }
+
+  if( nArg>1 && sqlite3_value_int(apVal[2 + p->nColumn + 2])<0 ){
+    rc = SQLITE_CONSTRAINT;
+    goto update_out;
+  }
+
+  /* Allocate space to hold the change in document sizes */
+  aSzDel = sqlite3_malloc64(sizeof(aSzDel[0])*((sqlite3_int64)p->nColumn+1)*2);
+  if( aSzDel==0 ){
+    rc = SQLITE_NOMEM;
+    goto update_out;
+  }
+  aSzIns = &aSzDel[p->nColumn+1];
+  memset(aSzDel, 0, sizeof(aSzDel[0])*(p->nColumn+1)*2);
+
+  rc = fts3Writelock(p);
+  if( rc!=SQLITE_OK ) goto update_out;
+
+  /* If this is an INSERT operation, or an UPDATE that modifies the rowid
+  ** value, then this operation requires constraint handling.
+  **
+  ** If the on-conflict mode is REPLACE, this means that the existing row
+  ** should be deleted from the database before inserting the new row. Or,
+  ** if the on-conflict mode is other than REPLACE, then this method must
+  ** detect the conflict and return SQLITE_CONSTRAINT before beginning to
+  ** modify the database file.
+  */
+  if( nArg>1 && p->zContentTbl==0 ){
+    /* Find the value object that holds the new rowid value. */
+    sqlite3_value *pNewRowid = apVal[3+p->nColumn];
+    if( sqlite3_value_type(pNewRowid)==SQLITE_NULL ){
+      pNewRowid = apVal[1];
+    }
+
+    if( sqlite3_value_type(pNewRowid)!=SQLITE_NULL && (
+        sqlite3_value_type(apVal[0])==SQLITE_NULL
+     || sqlite3_value_int64(apVal[0])!=sqlite3_value_int64(pNewRowid)
+    )){
+      /* The new rowid is not NULL (in this case the rowid will be
+      ** automatically assigned and there is no chance of a conflict), and
+      ** the statement is either an INSERT or an UPDATE that modifies the
+      ** rowid column. So if the conflict mode is REPLACE, then delete any
+      ** existing row with rowid=pNewRowid.
+      **
+      ** Or, if the conflict mode is not REPLACE, insert the new record into
+      ** the %_content table. If we hit the duplicate rowid constraint (or any
+      ** other error) while doing so, return immediately.
+      **
+      ** This branch may also run if pNewRowid contains a value that cannot
+      ** be losslessly converted to an integer. In this case, the eventual
+      ** call to fts3InsertData() (either just below or further on in this
+      ** function) will return SQLITE_MISMATCH. If fts3DeleteByRowid is
+      ** invoked, it will delete zero rows (since no row will have
+      ** docid=$pNewRowid if $pNewRowid is not an integer value).
+      */
+      if( sqlite3_vtab_on_conflict(p->db)==SQLITE_REPLACE ){
+        rc = fts3DeleteByRowid(p, pNewRowid, &nChng, aSzDel);
+      }else{
+        rc = fts3InsertData(p, apVal, pRowid);
+        bInsertDone = 1;
+      }
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    goto update_out;
+  }
+
+  /* If this is a DELETE or UPDATE operation, remove the old record. */
+  if( sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
+    assert( sqlite3_value_type(apVal[0])==SQLITE_INTEGER );
+    rc = fts3DeleteByRowid(p, apVal[0], &nChng, aSzDel);
+  }
+
+  /* If this is an INSERT or UPDATE operation, insert the new record. */
+  if( nArg>1 && rc==SQLITE_OK ){
+    int iLangid = sqlite3_value_int(apVal[2 + p->nColumn + 2]);
+    if( bInsertDone==0 ){
+      rc = fts3InsertData(p, apVal, pRowid);
+      if( rc==SQLITE_CONSTRAINT && p->zContentTbl==0 ){
+        rc = FTS_CORRUPT_VTAB;
+      }
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3PendingTermsDocid(p, 0, iLangid, *pRowid);
+    }
+    if( rc==SQLITE_OK ){
+      assert( p->iPrevDocid==*pRowid );
+      rc = fts3InsertTerms(p, iLangid, apVal, aSzIns);
+    }
+    if( p->bHasDocsize ){
+      fts3InsertDocsize(&rc, p, aSzIns);
+    }
+    nChng++;
+  }
+
+  if( p->bFts4 ){
+    fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nChng);
+  }
+
+ update_out:
+  sqlite3_free(aSzDel);
+  sqlite3Fts3SegmentsClose(p);
+  return rc;
+}
+
+/*
+** Flush any data in the pending-terms hash table to disk. If successful,
+** merge all segments in the database (including the new segment, if
+** there was any data to flush) into a single segment.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Optimize(Fts3Table *p){
+  int rc;
+  rc = sqlite3_exec(p->db, "SAVEPOINT fts3", 0, 0, 0);
+  if( rc==SQLITE_OK ){
+    rc = fts3DoOptimize(p, 1);
+    if( rc==SQLITE_OK || rc==SQLITE_DONE ){
+      int rc2 = sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
+      if( rc2!=SQLITE_OK ) rc = rc2;
+    }else{
+      sqlite3_exec(p->db, "ROLLBACK TO fts3", 0, 0, 0);
+      sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
+    }
+  }
+  sqlite3Fts3SegmentsClose(p);
+  return rc;
+}
+
+#endif
+
+/************** End of fts3_write.c ******************************************/
+/************** Begin file fts3_snippet.c ************************************/
+/*
+** 2009 Oct 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+#ifndef SQLITE_AMALGAMATION
+typedef sqlite3_int64 i64;
+#endif
+
+/*
+** Characters that may appear in the second argument to matchinfo().
+*/
+#define FTS3_MATCHINFO_NPHRASE   'p'        /* 1 value */
+#define FTS3_MATCHINFO_NCOL      'c'        /* 1 value */
+#define FTS3_MATCHINFO_NDOC      'n'        /* 1 value */
+#define FTS3_MATCHINFO_AVGLENGTH 'a'        /* nCol values */
+#define FTS3_MATCHINFO_LENGTH    'l'        /* nCol values */
+#define FTS3_MATCHINFO_LCS       's'        /* nCol values */
+#define FTS3_MATCHINFO_HITS      'x'        /* 3*nCol*nPhrase values */
+#define FTS3_MATCHINFO_LHITS     'y'        /* nCol*nPhrase values */
+#define FTS3_MATCHINFO_LHITS_BM  'b'        /* nCol*nPhrase values */
+
+/*
+** The default value for the second argument to matchinfo().
+*/
+#define FTS3_MATCHINFO_DEFAULT   "pcx"
+
+
+/*
+** Used as an sqlite3Fts3ExprIterate() context when loading phrase doclists to
+** Fts3Expr.aDoclist[]/nDoclist.
+*/
+typedef struct LoadDoclistCtx LoadDoclistCtx;
+struct LoadDoclistCtx {
+  Fts3Cursor *pCsr;               /* FTS3 Cursor */
+  int nPhrase;                    /* Number of phrases seen so far */
+  int nToken;                     /* Number of tokens seen so far */
+};
+
+/*
+** The following types are used as part of the implementation of the
+** fts3BestSnippet() routine.
+*/
+typedef struct SnippetIter SnippetIter;
+typedef struct SnippetPhrase SnippetPhrase;
+typedef struct SnippetFragment SnippetFragment;
+
+struct SnippetIter {
+  Fts3Cursor *pCsr;               /* Cursor snippet is being generated from */
+  int iCol;                       /* Extract snippet from this column */
+  int nSnippet;                   /* Requested snippet length (in tokens) */
+  int nPhrase;                    /* Number of phrases in query */
+  SnippetPhrase *aPhrase;         /* Array of size nPhrase */
+  int iCurrent;                   /* First token of current snippet */
+};
+
+struct SnippetPhrase {
+  int nToken;                     /* Number of tokens in phrase */
+  char *pList;                    /* Pointer to start of phrase position list */
+  i64 iHead;                      /* Next value in position list */
+  char *pHead;                    /* Position list data following iHead */
+  i64 iTail;                      /* Next value in trailing position list */
+  char *pTail;                    /* Position list data following iTail */
+};
+
+struct SnippetFragment {
+  int iCol;                       /* Column snippet is extracted from */
+  int iPos;                       /* Index of first token in snippet */
+  u64 covered;                    /* Mask of query phrases covered */
+  u64 hlmask;                     /* Mask of snippet terms to highlight */
+};
+
+/*
+** This type is used as an sqlite3Fts3ExprIterate() context object while
+** accumulating the data returned by the matchinfo() function.
+*/
+typedef struct MatchInfo MatchInfo;
+struct MatchInfo {
+  Fts3Cursor *pCursor;            /* FTS3 Cursor */
+  int nCol;                       /* Number of columns in table */
+  int nPhrase;                    /* Number of matchable phrases in query */
+  sqlite3_int64 nDoc;             /* Number of docs in database */
+  char flag;
+  u32 *aMatchinfo;                /* Pre-allocated buffer */
+};
+
+/*
+** An instance of this structure is used to manage a pair of buffers, each
+** (nElem * sizeof(u32)) bytes in size. See the MatchinfoBuffer code below
+** for details.
+*/
+struct MatchinfoBuffer {
+  u8 aRef[3];
+  int nElem;
+  int bGlobal;                    /* Set if global data is loaded */
+  char *zMatchinfo;
+  u32 aMatchinfo[1];
+};
+
+
+/*
+** The snippet() and offsets() functions both return text values. An instance
+** of the following structure is used to accumulate those values while the
+** functions are running. See fts3StringAppend() for details.
+*/
+typedef struct StrBuffer StrBuffer;
+struct StrBuffer {
+  char *z;                        /* Pointer to buffer containing string */
+  int n;                          /* Length of z in bytes (excl. nul-term) */
+  int nAlloc;                     /* Allocated size of buffer z in bytes */
+};
+
+
+/*************************************************************************
+** Start of MatchinfoBuffer code.
+*/
+
+/*
+** Allocate a two-slot MatchinfoBuffer object.
+*/
+static MatchinfoBuffer *fts3MIBufferNew(size_t nElem, const char *zMatchinfo){
+  MatchinfoBuffer *pRet;
+  sqlite3_int64 nByte = sizeof(u32) * (2*(sqlite3_int64)nElem + 1)
+                           + sizeof(MatchinfoBuffer);
+  sqlite3_int64 nStr = strlen(zMatchinfo);
+
+  pRet = sqlite3Fts3MallocZero(nByte + nStr+1);
+  if( pRet ){
+    pRet->aMatchinfo[0] = (u8*)(&pRet->aMatchinfo[1]) - (u8*)pRet;
+    pRet->aMatchinfo[1+nElem] = pRet->aMatchinfo[0]
+                                      + sizeof(u32)*((int)nElem+1);
+    pRet->nElem = (int)nElem;
+    pRet->zMatchinfo = ((char*)pRet) + nByte;
+    memcpy(pRet->zMatchinfo, zMatchinfo, nStr+1);
+    pRet->aRef[0] = 1;
+  }
+
+  return pRet;
+}
+
+static void fts3MIBufferFree(void *p){
+  MatchinfoBuffer *pBuf = (MatchinfoBuffer*)((u8*)p - ((u32*)p)[-1]);
+
+  assert( (u32*)p==&pBuf->aMatchinfo[1]
+       || (u32*)p==&pBuf->aMatchinfo[pBuf->nElem+2]
+  );
+  if( (u32*)p==&pBuf->aMatchinfo[1] ){
+    pBuf->aRef[1] = 0;
+  }else{
+    pBuf->aRef[2] = 0;
+  }
+
+  if( pBuf->aRef[0]==0 && pBuf->aRef[1]==0 && pBuf->aRef[2]==0 ){
+    sqlite3_free(pBuf);
+  }
+}
+
+static void (*fts3MIBufferAlloc(MatchinfoBuffer *p, u32 **paOut))(void*){
+  void (*xRet)(void*) = 0;
+  u32 *aOut = 0;
+
+  if( p->aRef[1]==0 ){
+    p->aRef[1] = 1;
+    aOut = &p->aMatchinfo[1];
+    xRet = fts3MIBufferFree;
+  }
+  else if( p->aRef[2]==0 ){
+    p->aRef[2] = 1;
+    aOut = &p->aMatchinfo[p->nElem+2];
+    xRet = fts3MIBufferFree;
+  }else{
+    aOut = (u32*)sqlite3_malloc64(p->nElem * sizeof(u32));
+    if( aOut ){
+      xRet = sqlite3_free;
+      if( p->bGlobal ) memcpy(aOut, &p->aMatchinfo[1], p->nElem*sizeof(u32));
+    }
+  }
+
+  *paOut = aOut;
+  return xRet;
+}
+
+static void fts3MIBufferSetGlobal(MatchinfoBuffer *p){
+  p->bGlobal = 1;
+  memcpy(&p->aMatchinfo[2+p->nElem], &p->aMatchinfo[1], p->nElem*sizeof(u32));
+}
+
+/*
+** Free a MatchinfoBuffer object allocated using fts3MIBufferNew()
+*/
+SQLITE_PRIVATE void sqlite3Fts3MIBufferFree(MatchinfoBuffer *p){
+  if( p ){
+    assert( p->aRef[0]==1 );
+    p->aRef[0] = 0;
+    if( p->aRef[0]==0 && p->aRef[1]==0 && p->aRef[2]==0 ){
+      sqlite3_free(p);
+    }
+  }
+}
+
+/*
+** End of MatchinfoBuffer code.
+*************************************************************************/
+
+
+/*
+** This function is used to help iterate through a position-list. A position
+** list is a list of unique integers, sorted from smallest to largest. Each
+** element of the list is represented by an FTS3 varint that takes the value
+** of the difference between the current element and the previous one plus
+** two. For example, to store the position-list:
+**
+**     4 9 113
+**
+** the three varints:
+**
+**     6 7 106
+**
+** are encoded.
+**
+** When this function is called, *pp points to the start of an element of
+** the list. *piPos contains the value of the previous entry in the list.
+** After it returns, *piPos contains the value of the next element of the
+** list and *pp is advanced to the following varint.
+*/
+static void fts3GetDeltaPosition(char **pp, i64 *piPos){
+  int iVal;
+  *pp += fts3GetVarint32(*pp, &iVal);
+  *piPos += (iVal-2);
+}
+
+/*
+** Helper function for sqlite3Fts3ExprIterate() (see below).
+*/
+static int fts3ExprIterate2(
+  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
+  int *piPhrase,                  /* Pointer to phrase counter */
+  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
+  void *pCtx                      /* Second argument to pass to callback */
+){
+  int rc;                         /* Return code */
+  int eType = pExpr->eType;     /* Type of expression node pExpr */
+
+  if( eType!=FTSQUERY_PHRASE ){
+    assert( pExpr->pLeft && pExpr->pRight );
+    rc = fts3ExprIterate2(pExpr->pLeft, piPhrase, x, pCtx);
+    if( rc==SQLITE_OK && eType!=FTSQUERY_NOT ){
+      rc = fts3ExprIterate2(pExpr->pRight, piPhrase, x, pCtx);
+    }
+  }else{
+    rc = x(pExpr, *piPhrase, pCtx);
+    (*piPhrase)++;
+  }
+  return rc;
+}
+
+/*
+** Iterate through all phrase nodes in an FTS3 query, except those that
+** are part of a sub-tree that is the right-hand-side of a NOT operator.
+** For each phrase node found, the supplied callback function is invoked.
+**
+** If the callback function returns anything other than SQLITE_OK,
+** the iteration is abandoned and the error code returned immediately.
+** Otherwise, SQLITE_OK is returned after a callback has been made for
+** all eligible phrase nodes.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ExprIterate(
+  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
+  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
+  void *pCtx                      /* Second argument to pass to callback */
+){
+  int iPhrase = 0;                /* Variable used as the phrase counter */
+  return fts3ExprIterate2(pExpr, &iPhrase, x, pCtx);
+}
+
+/*
+** This is an sqlite3Fts3ExprIterate() callback used while loading the
+** doclists for each phrase into Fts3Expr.aDoclist[]/nDoclist. See also
+** fts3ExprLoadDoclists().
+*/
+static int fts3ExprLoadDoclistsCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  int rc = SQLITE_OK;
+  Fts3Phrase *pPhrase = pExpr->pPhrase;
+  LoadDoclistCtx *p = (LoadDoclistCtx *)ctx;
+
+  UNUSED_PARAMETER(iPhrase);
+
+  p->nPhrase++;
+  p->nToken += pPhrase->nToken;
+
+  return rc;
+}
+
+/*
+** Load the doclists for each phrase in the query associated with FTS3 cursor
+** pCsr.
+**
+** If pnPhrase is not NULL, then *pnPhrase is set to the number of matchable
+** phrases in the expression (all phrases except those directly or
+** indirectly descended from the right-hand-side of a NOT operator). If
+** pnToken is not NULL, then it is set to the number of tokens in all
+** matchable phrases of the expression.
+*/
+static int fts3ExprLoadDoclists(
+  Fts3Cursor *pCsr,               /* Fts3 cursor for current query */
+  int *pnPhrase,                  /* OUT: Number of phrases in query */
+  int *pnToken                    /* OUT: Number of tokens in query */
+){
+  int rc;                         /* Return Code */
+  LoadDoclistCtx sCtx = {0,0,0};  /* Context for sqlite3Fts3ExprIterate() */
+  sCtx.pCsr = pCsr;
+  rc = sqlite3Fts3ExprIterate(pCsr->pExpr,fts3ExprLoadDoclistsCb,(void*)&sCtx);
+  if( pnPhrase ) *pnPhrase = sCtx.nPhrase;
+  if( pnToken ) *pnToken = sCtx.nToken;
+  return rc;
+}
+
+static int fts3ExprPhraseCountCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  (*(int *)ctx)++;
+  pExpr->iPhrase = iPhrase;
+  return SQLITE_OK;
+}
+static int fts3ExprPhraseCount(Fts3Expr *pExpr){
+  int nPhrase = 0;
+  (void)sqlite3Fts3ExprIterate(pExpr, fts3ExprPhraseCountCb, (void *)&nPhrase);
+  return nPhrase;
+}
+
+/*
+** Advance the position list iterator specified by the first two
+** arguments so that it points to the first element with a value greater
+** than or equal to parameter iNext.
+*/
+static void fts3SnippetAdvance(char **ppIter, i64 *piIter, int iNext){
+  char *pIter = *ppIter;
+  if( pIter ){
+    i64 iIter = *piIter;
+
+    while( iIter<iNext ){
+      if( 0==(*pIter & 0xFE) ){
+        iIter = -1;
+        pIter = 0;
+        break;
+      }
+      fts3GetDeltaPosition(&pIter, &iIter);
+    }
+
+    *piIter = iIter;
+    *ppIter = pIter;
+  }
+}
+
+/*
+** Advance the snippet iterator to the next candidate snippet.
+*/
+static int fts3SnippetNextCandidate(SnippetIter *pIter){
+  int i;                          /* Loop counter */
+
+  if( pIter->iCurrent<0 ){
+    /* The SnippetIter object has just been initialized. The first snippet
+    ** candidate always starts at offset 0 (even if this candidate has a
+    ** score of 0.0).
+    */
+    pIter->iCurrent = 0;
+
+    /* Advance the 'head' iterator of each phrase to the first offset that
+    ** is greater than or equal to (iNext+nSnippet).
+    */
+    for(i=0; i<pIter->nPhrase; i++){
+      SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+      fts3SnippetAdvance(&pPhrase->pHead, &pPhrase->iHead, pIter->nSnippet);
+    }
+  }else{
+    int iStart;
+    int iEnd = 0x7FFFFFFF;
+
+    for(i=0; i<pIter->nPhrase; i++){
+      SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+      if( pPhrase->pHead && pPhrase->iHead<iEnd ){
+        iEnd = pPhrase->iHead;
+      }
+    }
+    if( iEnd==0x7FFFFFFF ){
+      return 1;
+    }
+
+    assert( pIter->nSnippet>=0 );
+    pIter->iCurrent = iStart = iEnd - pIter->nSnippet + 1;
+    for(i=0; i<pIter->nPhrase; i++){
+      SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+      fts3SnippetAdvance(&pPhrase->pHead, &pPhrase->iHead, iEnd+1);
+      fts3SnippetAdvance(&pPhrase->pTail, &pPhrase->iTail, iStart);
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Retrieve information about the current candidate snippet of snippet
+** iterator pIter.
+*/
+static void fts3SnippetDetails(
+  SnippetIter *pIter,             /* Snippet iterator */
+  u64 mCovered,                   /* Bitmask of phrases already covered */
+  int *piToken,                   /* OUT: First token of proposed snippet */
+  int *piScore,                   /* OUT: "Score" for this snippet */
+  u64 *pmCover,                   /* OUT: Bitmask of phrases covered */
+  u64 *pmHighlight                /* OUT: Bitmask of terms to highlight */
+){
+  int iStart = pIter->iCurrent;   /* First token of snippet */
+  int iScore = 0;                 /* Score of this snippet */
+  int i;                          /* Loop counter */
+  u64 mCover = 0;                 /* Mask of phrases covered by this snippet */
+  u64 mHighlight = 0;             /* Mask of tokens to highlight in snippet */
+
+  for(i=0; i<pIter->nPhrase; i++){
+    SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+    if( pPhrase->pTail ){
+      char *pCsr = pPhrase->pTail;
+      i64 iCsr = pPhrase->iTail;
+
+      while( iCsr<(iStart+pIter->nSnippet) && iCsr>=iStart ){
+        int j;
+        u64 mPhrase = (u64)1 << (i%64);
+        u64 mPos = (u64)1 << (iCsr - iStart);
+        assert( iCsr>=iStart && (iCsr - iStart)<=64 );
+        assert( i>=0 );
+        if( (mCover|mCovered)&mPhrase ){
+          iScore++;
+        }else{
+          iScore += 1000;
+        }
+        mCover |= mPhrase;
+
+        for(j=0; j<pPhrase->nToken && j<pIter->nSnippet; j++){
+          mHighlight |= (mPos>>j);
+        }
+
+        if( 0==(*pCsr & 0x0FE) ) break;
+        fts3GetDeltaPosition(&pCsr, &iCsr);
+      }
+    }
+  }
+
+  /* Set the output variables before returning. */
+  *piToken = iStart;
+  *piScore = iScore;
+  *pmCover = mCover;
+  *pmHighlight = mHighlight;
+}
+
+/*
+** This function is an sqlite3Fts3ExprIterate() callback used by
+** fts3BestSnippet().  Each invocation populates an element of the
+** SnippetIter.aPhrase[] array.
+*/
+static int fts3SnippetFindPositions(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  SnippetIter *p = (SnippetIter *)ctx;
+  SnippetPhrase *pPhrase = &p->aPhrase[iPhrase];
+  char *pCsr;
+  int rc;
+
+  pPhrase->nToken = pExpr->pPhrase->nToken;
+  rc = sqlite3Fts3EvalPhrasePoslist(p->pCsr, pExpr, p->iCol, &pCsr);
+  assert( rc==SQLITE_OK || pCsr==0 );
+  if( pCsr ){
+    i64 iFirst = 0;
+    pPhrase->pList = pCsr;
+    fts3GetDeltaPosition(&pCsr, &iFirst);
+    if( iFirst<0 ){
+      rc = FTS_CORRUPT_VTAB;
+    }else{
+      pPhrase->pHead = pCsr;
+      pPhrase->pTail = pCsr;
+      pPhrase->iHead = iFirst;
+      pPhrase->iTail = iFirst;
+    }
+  }else{
+    assert( rc!=SQLITE_OK || (
+       pPhrase->pList==0 && pPhrase->pHead==0 && pPhrase->pTail==0
+    ));
+  }
+
+  return rc;
+}
+
+/*
+** Select the fragment of text consisting of nFragment contiguous tokens
+** from column iCol that represent the "best" snippet. The best snippet
+** is the snippet with the highest score, where scores are calculated
+** by adding:
+**
+**   (a) +1 point for each occurrence of a matchable phrase in the snippet.
+**
+**   (b) +1000 points for the first occurrence of each matchable phrase in
+**       the snippet for which the corresponding mCovered bit is not set.
+**
+** The selected snippet parameters are stored in structure *pFragment before
+** returning. The score of the selected snippet is stored in *piScore
+** before returning.
+*/
+static int fts3BestSnippet(
+  int nSnippet,                   /* Desired snippet length */
+  Fts3Cursor *pCsr,               /* Cursor to create snippet for */
+  int iCol,                       /* Index of column to create snippet from */
+  u64 mCovered,                   /* Mask of phrases already covered */
+  u64 *pmSeen,                    /* IN/OUT: Mask of phrases seen */
+  SnippetFragment *pFragment,     /* OUT: Best snippet found */
+  int *piScore                    /* OUT: Score of snippet pFragment */
+){
+  int rc;                         /* Return Code */
+  int nList;                      /* Number of phrases in expression */
+  SnippetIter sIter;              /* Iterates through snippet candidates */
+  sqlite3_int64 nByte;            /* Number of bytes of space to allocate */
+  int iBestScore = -1;            /* Best snippet score found so far */
+  int i;                          /* Loop counter */
+
+  memset(&sIter, 0, sizeof(sIter));
+
+  /* Iterate through the phrases in the expression to count them. The same
+  ** callback makes sure the doclists are loaded for each phrase.
+  */
+  rc = fts3ExprLoadDoclists(pCsr, &nList, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* Now that it is known how many phrases there are, allocate and zero
+  ** the required space using malloc().
+  */
+  nByte = sizeof(SnippetPhrase) * nList;
+  sIter.aPhrase = (SnippetPhrase *)sqlite3Fts3MallocZero(nByte);
+  if( !sIter.aPhrase ){
+    return SQLITE_NOMEM;
+  }
+
+  /* Initialize the contents of the SnippetIter object. Then iterate through
+  ** the set of phrases in the expression to populate the aPhrase[] array.
+  */
+  sIter.pCsr = pCsr;
+  sIter.iCol = iCol;
+  sIter.nSnippet = nSnippet;
+  sIter.nPhrase = nList;
+  sIter.iCurrent = -1;
+  rc = sqlite3Fts3ExprIterate(
+      pCsr->pExpr, fts3SnippetFindPositions, (void*)&sIter
+  );
+  if( rc==SQLITE_OK ){
+
+    /* Set the *pmSeen output variable. */
+    for(i=0; i<nList; i++){
+      if( sIter.aPhrase[i].pHead ){
+        *pmSeen |= (u64)1 << (i%64);
+      }
+    }
+
+    /* Loop through all candidate snippets. Store the best snippet in
+     ** *pFragment. Store its associated 'score' in iBestScore.
+     */
+    pFragment->iCol = iCol;
+    while( !fts3SnippetNextCandidate(&sIter) ){
+      int iPos;
+      int iScore;
+      u64 mCover;
+      u64 mHighlite;
+      fts3SnippetDetails(&sIter, mCovered, &iPos, &iScore, &mCover,&mHighlite);
+      assert( iScore>=0 );
+      if( iScore>iBestScore ){
+        pFragment->iPos = iPos;
+        pFragment->hlmask = mHighlite;
+        pFragment->covered = mCover;
+        iBestScore = iScore;
+      }
+    }
+
+    *piScore = iBestScore;
+  }
+  sqlite3_free(sIter.aPhrase);
+  return rc;
+}
+
+
+/*
+** Append a string to the string-buffer passed as the first argument.
+**
+** If nAppend is negative, then the length of the string zAppend is
+** determined using strlen().
+*/
+static int fts3StringAppend(
+  StrBuffer *pStr,                /* Buffer to append to */
+  const char *zAppend,            /* Pointer to data to append to buffer */
+  int nAppend                     /* Size of zAppend in bytes (or -1) */
+){
+  if( nAppend<0 ){
+    nAppend = (int)strlen(zAppend);
+  }
+
+  /* If there is insufficient space allocated at StrBuffer.z, use realloc()
+  ** to grow the buffer until so that it is big enough to accomadate the
+  ** appended data.
+  */
+  if( pStr->n+nAppend+1>=pStr->nAlloc ){
+    sqlite3_int64 nAlloc = pStr->nAlloc+(sqlite3_int64)nAppend+100;
+    char *zNew = sqlite3_realloc64(pStr->z, nAlloc);
+    if( !zNew ){
+      return SQLITE_NOMEM;
+    }
+    pStr->z = zNew;
+    pStr->nAlloc = nAlloc;
+  }
+  assert( pStr->z!=0 && (pStr->nAlloc >= pStr->n+nAppend+1) );
+
+  /* Append the data to the string buffer. */
+  memcpy(&pStr->z[pStr->n], zAppend, nAppend);
+  pStr->n += nAppend;
+  pStr->z[pStr->n] = '\0';
+
+  return SQLITE_OK;
+}
+
+/*
+** The fts3BestSnippet() function often selects snippets that end with a
+** query term. That is, the final term of the snippet is always a term
+** that requires highlighting. For example, if 'X' is a highlighted term
+** and '.' is a non-highlighted term, BestSnippet() may select:
+**
+**     ........X.....X
+**
+** This function "shifts" the beginning of the snippet forward in the
+** document so that there are approximately the same number of
+** non-highlighted terms to the right of the final highlighted term as there
+** are to the left of the first highlighted term. For example, to this:
+**
+**     ....X.....X....
+**
+** This is done as part of extracting the snippet text, not when selecting
+** the snippet. Snippet selection is done based on doclists only, so there
+** is no way for fts3BestSnippet() to know whether or not the document
+** actually contains terms that follow the final highlighted term.
+*/
+static int fts3SnippetShift(
+  Fts3Table *pTab,                /* FTS3 table snippet comes from */
+  int iLangid,                    /* Language id to use in tokenizing */
+  int nSnippet,                   /* Number of tokens desired for snippet */
+  const char *zDoc,               /* Document text to extract snippet from */
+  int nDoc,                       /* Size of buffer zDoc in bytes */
+  int *piPos,                     /* IN/OUT: First token of snippet */
+  u64 *pHlmask                    /* IN/OUT: Mask of tokens to highlight */
+){
+  u64 hlmask = *pHlmask;          /* Local copy of initial highlight-mask */
+
+  if( hlmask ){
+    int nLeft;                    /* Tokens to the left of first highlight */
+    int nRight;                   /* Tokens to the right of last highlight */
+    int nDesired;                 /* Ideal number of tokens to shift forward */
+
+    for(nLeft=0; !(hlmask & ((u64)1 << nLeft)); nLeft++);
+    for(nRight=0; !(hlmask & ((u64)1 << (nSnippet-1-nRight))); nRight++);
+    assert( (nSnippet-1-nRight)<=63 && (nSnippet-1-nRight)>=0 );
+    nDesired = (nLeft-nRight)/2;
+
+    /* Ideally, the start of the snippet should be pushed forward in the
+    ** document nDesired tokens. This block checks if there are actually
+    ** nDesired tokens to the right of the snippet. If so, *piPos and
+    ** *pHlMask are updated to shift the snippet nDesired tokens to the
+    ** right. Otherwise, the snippet is shifted by the number of tokens
+    ** available.
+    */
+    if( nDesired>0 ){
+      int nShift;                 /* Number of tokens to shift snippet by */
+      int iCurrent = 0;           /* Token counter */
+      int rc;                     /* Return Code */
+      sqlite3_tokenizer_module *pMod;
+      sqlite3_tokenizer_cursor *pC;
+      pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
+
+      /* Open a cursor on zDoc/nDoc. Check if there are (nSnippet+nDesired)
+      ** or more tokens in zDoc/nDoc.
+      */
+      rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, iLangid, zDoc, nDoc, &pC);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      while( rc==SQLITE_OK && iCurrent<(nSnippet+nDesired) ){
+        const char *ZDUMMY; int DUMMY1 = 0, DUMMY2 = 0, DUMMY3 = 0;
+        rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &DUMMY2, &DUMMY3, &iCurrent);
+      }
+      pMod->xClose(pC);
+      if( rc!=SQLITE_OK && rc!=SQLITE_DONE ){ return rc; }
+
+      nShift = (rc==SQLITE_DONE)+iCurrent-nSnippet;
+      assert( nShift<=nDesired );
+      if( nShift>0 ){
+        *piPos += nShift;
+        *pHlmask = hlmask >> nShift;
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Extract the snippet text for fragment pFragment from cursor pCsr and
+** append it to string buffer pOut.
+*/
+static int fts3SnippetText(
+  Fts3Cursor *pCsr,               /* FTS3 Cursor */
+  SnippetFragment *pFragment,     /* Snippet to extract */
+  int iFragment,                  /* Fragment number */
+  int isLast,                     /* True for final fragment in snippet */
+  int nSnippet,                   /* Number of tokens in extracted snippet */
+  const char *zOpen,              /* String inserted before highlighted term */
+  const char *zClose,             /* String inserted after highlighted term */
+  const char *zEllipsis,          /* String inserted between snippets */
+  StrBuffer *pOut                 /* Write output here */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc;                         /* Return code */
+  const char *zDoc;               /* Document text to extract snippet from */
+  int nDoc;                       /* Size of zDoc in bytes */
+  int iCurrent = 0;               /* Current token number of document */
+  int iEnd = 0;                   /* Byte offset of end of current token */
+  int isShiftDone = 0;            /* True after snippet is shifted */
+  int iPos = pFragment->iPos;     /* First token of snippet */
+  u64 hlmask = pFragment->hlmask; /* Highlight-mask for snippet */
+  int iCol = pFragment->iCol+1;   /* Query column to extract text from */
+  sqlite3_tokenizer_module *pMod; /* Tokenizer module methods object */
+  sqlite3_tokenizer_cursor *pC;   /* Tokenizer cursor open on zDoc/nDoc */
+
+  zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol);
+  if( zDoc==0 ){
+    if( sqlite3_column_type(pCsr->pStmt, iCol)!=SQLITE_NULL ){
+      return SQLITE_NOMEM;
+    }
+    return SQLITE_OK;
+  }
+  nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol);
+
+  /* Open a token cursor on the document. */
+  pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
+  rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, pCsr->iLangid, zDoc,nDoc,&pC);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  while( rc==SQLITE_OK ){
+    const char *ZDUMMY;           /* Dummy argument used with tokenizer */
+    int DUMMY1 = -1;              /* Dummy argument used with tokenizer */
+    int iBegin = 0;               /* Offset in zDoc of start of token */
+    int iFin = 0;                 /* Offset in zDoc of end of token */
+    int isHighlight = 0;          /* True for highlighted terms */
+
+    /* Variable DUMMY1 is initialized to a negative value above. Elsewhere
+    ** in the FTS code the variable that the third argument to xNext points to
+    ** is initialized to zero before the first (*but not necessarily
+    ** subsequent*) call to xNext(). This is done for a particular application
+    ** that needs to know whether or not the tokenizer is being used for
+    ** snippet generation or for some other purpose.
+    **
+    ** Extreme care is required when writing code to depend on this
+    ** initialization. It is not a documented part of the tokenizer interface.
+    ** If a tokenizer is used directly by any code outside of FTS, this
+    ** convention might not be respected.  */
+    rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &iBegin, &iFin, &iCurrent);
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_DONE ){
+        /* Special case - the last token of the snippet is also the last token
+        ** of the column. Append any punctuation that occurred between the end
+        ** of the previous token and the end of the document to the output.
+        ** Then break out of the loop. */
+        rc = fts3StringAppend(pOut, &zDoc[iEnd], -1);
+      }
+      break;
+    }
+    if( iCurrent<iPos ){ continue; }
+
+    if( !isShiftDone ){
+      int n = nDoc - iBegin;
+      rc = fts3SnippetShift(
+          pTab, pCsr->iLangid, nSnippet, &zDoc[iBegin], n, &iPos, &hlmask
+      );
+      isShiftDone = 1;
+
+      /* Now that the shift has been done, check if the initial "..." are
+      ** required. They are required if (a) this is not the first fragment,
+      ** or (b) this fragment does not begin at position 0 of its column.
+      */
+      if( rc==SQLITE_OK ){
+        if( iPos>0 || iFragment>0 ){
+          rc = fts3StringAppend(pOut, zEllipsis, -1);
+        }else if( iBegin ){
+          rc = fts3StringAppend(pOut, zDoc, iBegin);
+        }
+      }
+      if( rc!=SQLITE_OK || iCurrent<iPos ) continue;
+    }
+
+    if( iCurrent>=(iPos+nSnippet) ){
+      if( isLast ){
+        rc = fts3StringAppend(pOut, zEllipsis, -1);
+      }
+      break;
+    }
+
+    /* Set isHighlight to true if this term should be highlighted. */
+    isHighlight = (hlmask & ((u64)1 << (iCurrent-iPos)))!=0;
+
+    if( iCurrent>iPos ) rc = fts3StringAppend(pOut, &zDoc[iEnd], iBegin-iEnd);
+    if( rc==SQLITE_OK && isHighlight ) rc = fts3StringAppend(pOut, zOpen, -1);
+    if( rc==SQLITE_OK ) rc = fts3StringAppend(pOut, &zDoc[iBegin], iFin-iBegin);
+    if( rc==SQLITE_OK && isHighlight ) rc = fts3StringAppend(pOut, zClose, -1);
+
+    iEnd = iFin;
+  }
+
+  pMod->xClose(pC);
+  return rc;
+}
+
+
+/*
+** This function is used to count the entries in a column-list (a
+** delta-encoded list of term offsets within a single column of a single
+** row). When this function is called, *ppCollist should point to the
+** beginning of the first varint in the column-list (the varint that
+** contains the position of the first matching term in the column data).
+** Before returning, *ppCollist is set to point to the first byte after
+** the last varint in the column-list (either the 0x00 signifying the end
+** of the position-list, or the 0x01 that precedes the column number of
+** the next column in the position-list).
+**
+** The number of elements in the column-list is returned.
+*/
+static int fts3ColumnlistCount(char **ppCollist){
+  char *pEnd = *ppCollist;
+  char c = 0;
+  int nEntry = 0;
+
+  /* A column-list is terminated by either a 0x01 or 0x00. */
+  while( 0xFE & (*pEnd | c) ){
+    c = *pEnd++ & 0x80;
+    if( !c ) nEntry++;
+  }
+
+  *ppCollist = pEnd;
+  return nEntry;
+}
+
+/*
+** This function gathers 'y' or 'b' data for a single phrase.
+*/
+static int fts3ExprLHits(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  MatchInfo *p                    /* Matchinfo context */
+){
+  Fts3Table *pTab = (Fts3Table *)p->pCursor->base.pVtab;
+  int iStart;
+  Fts3Phrase *pPhrase = pExpr->pPhrase;
+  char *pIter = pPhrase->doclist.pList;
+  int iCol = 0;
+
+  assert( p->flag==FTS3_MATCHINFO_LHITS_BM || p->flag==FTS3_MATCHINFO_LHITS );
+  if( p->flag==FTS3_MATCHINFO_LHITS ){
+    iStart = pExpr->iPhrase * p->nCol;
+  }else{
+    iStart = pExpr->iPhrase * ((p->nCol + 31) / 32);
+  }
+
+  if( pIter ) while( 1 ){
+    int nHit = fts3ColumnlistCount(&pIter);
+    if( (pPhrase->iColumn>=pTab->nColumn || pPhrase->iColumn==iCol) ){
+      if( p->flag==FTS3_MATCHINFO_LHITS ){
+        p->aMatchinfo[iStart + iCol] = (u32)nHit;
+      }else if( nHit ){
+        p->aMatchinfo[iStart + (iCol+1)/32] |= (1 << (iCol&0x1F));
+      }
+    }
+    assert( *pIter==0x00 || *pIter==0x01 );
+    if( *pIter!=0x01 ) break;
+    pIter++;
+    pIter += fts3GetVarint32(pIter, &iCol);
+    if( iCol>=p->nCol ) return FTS_CORRUPT_VTAB;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Gather the results for matchinfo directives 'y' and 'b'.
+*/
+static int fts3ExprLHitGather(
+  Fts3Expr *pExpr,
+  MatchInfo *p
+){
+  int rc = SQLITE_OK;
+  assert( (pExpr->pLeft==0)==(pExpr->pRight==0) );
+  if( pExpr->bEof==0 && pExpr->iDocid==p->pCursor->iPrevId ){
+    if( pExpr->pLeft ){
+      rc = fts3ExprLHitGather(pExpr->pLeft, p);
+      if( rc==SQLITE_OK ) rc = fts3ExprLHitGather(pExpr->pRight, p);
+    }else{
+      rc = fts3ExprLHits(pExpr, p);
+    }
+  }
+  return rc;
+}
+
+/*
+** sqlite3Fts3ExprIterate() callback used to collect the "global" matchinfo
+** stats for a single query.
+**
+** sqlite3Fts3ExprIterate() callback to load the 'global' elements of a
+** FTS3_MATCHINFO_HITS matchinfo array. The global stats are those elements
+** of the matchinfo array that are constant for all rows returned by the
+** current query.
+**
+** Argument pCtx is actually a pointer to a struct of type MatchInfo. This
+** function populates Matchinfo.aMatchinfo[] as follows:
+**
+**   for(iCol=0; iCol<nCol; iCol++){
+**     aMatchinfo[3*iPhrase*nCol + 3*iCol + 1] = X;
+**     aMatchinfo[3*iPhrase*nCol + 3*iCol + 2] = Y;
+**   }
+**
+** where X is the number of matches for phrase iPhrase is column iCol of all
+** rows of the table. Y is the number of rows for which column iCol contains
+** at least one instance of phrase iPhrase.
+**
+** If the phrase pExpr consists entirely of deferred tokens, then all X and
+** Y values are set to nDoc, where nDoc is the number of documents in the
+** file system. This is done because the full-text index doclist is required
+** to calculate these values properly, and the full-text index doclist is
+** not available for deferred tokens.
+*/
+static int fts3ExprGlobalHitsCb(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  int iPhrase,                    /* Phrase number (numbered from zero) */
+  void *pCtx                      /* Pointer to MatchInfo structure */
+){
+  MatchInfo *p = (MatchInfo *)pCtx;
+  return sqlite3Fts3EvalPhraseStats(
+      p->pCursor, pExpr, &p->aMatchinfo[3*iPhrase*p->nCol]
+  );
+}
+
+/*
+** sqlite3Fts3ExprIterate() callback used to collect the "local" part of the
+** FTS3_MATCHINFO_HITS array. The local stats are those elements of the
+** array that are different for each row returned by the query.
+*/
+static int fts3ExprLocalHitsCb(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  int iPhrase,                    /* Phrase number */
+  void *pCtx                      /* Pointer to MatchInfo structure */
+){
+  int rc = SQLITE_OK;
+  MatchInfo *p = (MatchInfo *)pCtx;
+  int iStart = iPhrase * p->nCol * 3;
+  int i;
+
+  for(i=0; i<p->nCol && rc==SQLITE_OK; i++){
+    char *pCsr;
+    rc = sqlite3Fts3EvalPhrasePoslist(p->pCursor, pExpr, i, &pCsr);
+    if( pCsr ){
+      p->aMatchinfo[iStart+i*3] = fts3ColumnlistCount(&pCsr);
+    }else{
+      p->aMatchinfo[iStart+i*3] = 0;
+    }
+  }
+
+  return rc;
+}
+
+static int fts3MatchinfoCheck(
+  Fts3Table *pTab,
+  char cArg,
+  char **pzErr
+){
+  if( (cArg==FTS3_MATCHINFO_NPHRASE)
+   || (cArg==FTS3_MATCHINFO_NCOL)
+   || (cArg==FTS3_MATCHINFO_NDOC && pTab->bFts4)
+   || (cArg==FTS3_MATCHINFO_AVGLENGTH && pTab->bFts4)
+   || (cArg==FTS3_MATCHINFO_LENGTH && pTab->bHasDocsize)
+   || (cArg==FTS3_MATCHINFO_LCS)
+   || (cArg==FTS3_MATCHINFO_HITS)
+   || (cArg==FTS3_MATCHINFO_LHITS)
+   || (cArg==FTS3_MATCHINFO_LHITS_BM)
+  ){
+    return SQLITE_OK;
+  }
+  sqlite3Fts3ErrMsg(pzErr, "unrecognized matchinfo request: %c", cArg);
+  return SQLITE_ERROR;
+}
+
+static size_t fts3MatchinfoSize(MatchInfo *pInfo, char cArg){
+  size_t nVal;                      /* Number of integers output by cArg */
+
+  switch( cArg ){
+    case FTS3_MATCHINFO_NDOC:
+    case FTS3_MATCHINFO_NPHRASE:
+    case FTS3_MATCHINFO_NCOL:
+      nVal = 1;
+      break;
+
+    case FTS3_MATCHINFO_AVGLENGTH:
+    case FTS3_MATCHINFO_LENGTH:
+    case FTS3_MATCHINFO_LCS:
+      nVal = pInfo->nCol;
+      break;
+
+    case FTS3_MATCHINFO_LHITS:
+      nVal = pInfo->nCol * pInfo->nPhrase;
+      break;
+
+    case FTS3_MATCHINFO_LHITS_BM:
+      nVal = pInfo->nPhrase * ((pInfo->nCol + 31) / 32);
+      break;
+
+    default:
+      assert( cArg==FTS3_MATCHINFO_HITS );
+      nVal = pInfo->nCol * pInfo->nPhrase * 3;
+      break;
+  }
+
+  return nVal;
+}
+
+static int fts3MatchinfoSelectDoctotal(
+  Fts3Table *pTab,
+  sqlite3_stmt **ppStmt,
+  sqlite3_int64 *pnDoc,
+  const char **paLen,
+  const char **ppEnd
+){
+  sqlite3_stmt *pStmt;
+  const char *a;
+  const char *pEnd;
+  sqlite3_int64 nDoc;
+  int n;
+
+
+  if( !*ppStmt ){
+    int rc = sqlite3Fts3SelectDoctotal(pTab, ppStmt);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  pStmt = *ppStmt;
+  assert( sqlite3_data_count(pStmt)==1 );
+
+  n = sqlite3_column_bytes(pStmt, 0);
+  a = sqlite3_column_blob(pStmt, 0);
+  if( a==0 ){
+    return FTS_CORRUPT_VTAB;
+  }
+  pEnd = a + n;
+  a += sqlite3Fts3GetVarintBounded(a, pEnd, &nDoc);
+  if( nDoc<=0 || a>pEnd ){
+    return FTS_CORRUPT_VTAB;
+  }
+  *pnDoc = nDoc;
+
+  if( paLen ) *paLen = a;
+  if( ppEnd ) *ppEnd = pEnd;
+  return SQLITE_OK;
+}
+
+/*
+** An instance of the following structure is used to store state while
+** iterating through a multi-column position-list corresponding to the
+** hits for a single phrase on a single row in order to calculate the
+** values for a matchinfo() FTS3_MATCHINFO_LCS request.
+*/
+typedef struct LcsIterator LcsIterator;
+struct LcsIterator {
+  Fts3Expr *pExpr;                /* Pointer to phrase expression */
+  int iPosOffset;                 /* Tokens count up to end of this phrase */
+  char *pRead;                    /* Cursor used to iterate through aDoclist */
+  int iPos;                       /* Current position */
+};
+
+/*
+** If LcsIterator.iCol is set to the following value, the iterator has
+** finished iterating through all offsets for all columns.
+*/
+#define LCS_ITERATOR_FINISHED 0x7FFFFFFF;
+
+static int fts3MatchinfoLcsCb(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  int iPhrase,                    /* Phrase number (numbered from zero) */
+  void *pCtx                      /* Pointer to MatchInfo structure */
+){
+  LcsIterator *aIter = (LcsIterator *)pCtx;
+  aIter[iPhrase].pExpr = pExpr;
+  return SQLITE_OK;
+}
+
+/*
+** Advance the iterator passed as an argument to the next position. Return
+** 1 if the iterator is at EOF or if it now points to the start of the
+** position list for the next column.
+*/
+static int fts3LcsIteratorAdvance(LcsIterator *pIter){
+  char *pRead;
+  sqlite3_int64 iRead;
+  int rc = 0;
+
+  if( NEVER(pIter==0) ) return 1;
+  pRead = pIter->pRead;
+  pRead += sqlite3Fts3GetVarint(pRead, &iRead);
+  if( iRead==0 || iRead==1 ){
+    pRead = 0;
+    rc = 1;
+  }else{
+    pIter->iPos += (int)(iRead-2);
+  }
+
+  pIter->pRead = pRead;
+  return rc;
+}
+
+/*
+** This function implements the FTS3_MATCHINFO_LCS matchinfo() flag.
+**
+** If the call is successful, the longest-common-substring lengths for each
+** column are written into the first nCol elements of the pInfo->aMatchinfo[]
+** array before returning. SQLITE_OK is returned in this case.
+**
+** Otherwise, if an error occurs, an SQLite error code is returned and the
+** data written to the first nCol elements of pInfo->aMatchinfo[] is
+** undefined.
+*/
+static int fts3MatchinfoLcs(Fts3Cursor *pCsr, MatchInfo *pInfo){
+  LcsIterator *aIter;
+  int i;
+  int iCol;
+  int nToken = 0;
+  int rc = SQLITE_OK;
+
+  /* Allocate and populate the array of LcsIterator objects. The array
+  ** contains one element for each matchable phrase in the query.
+  **/
+  aIter = sqlite3Fts3MallocZero(sizeof(LcsIterator) * pCsr->nPhrase);
+  if( !aIter ) return SQLITE_NOMEM;
+  (void)sqlite3Fts3ExprIterate(pCsr->pExpr, fts3MatchinfoLcsCb, (void*)aIter);
+
+  for(i=0; i<pInfo->nPhrase; i++){
+    LcsIterator *pIter = &aIter[i];
+    nToken -= pIter->pExpr->pPhrase->nToken;
+    pIter->iPosOffset = nToken;
+  }
+
+  for(iCol=0; iCol<pInfo->nCol; iCol++){
+    int nLcs = 0;                 /* LCS value for this column */
+    int nLive = 0;                /* Number of iterators in aIter not at EOF */
+
+    for(i=0; i<pInfo->nPhrase; i++){
+      LcsIterator *pIt = &aIter[i];
+      rc = sqlite3Fts3EvalPhrasePoslist(pCsr, pIt->pExpr, iCol, &pIt->pRead);
+      if( rc!=SQLITE_OK ) goto matchinfo_lcs_out;
+      if( pIt->pRead ){
+        pIt->iPos = pIt->iPosOffset;
+        fts3LcsIteratorAdvance(pIt);
+        if( pIt->pRead==0 ){
+          rc = FTS_CORRUPT_VTAB;
+          goto matchinfo_lcs_out;
+        }
+        nLive++;
+      }
+    }
+
+    while( nLive>0 ){
+      LcsIterator *pAdv = 0;      /* The iterator to advance by one position */
+      int nThisLcs = 0;           /* LCS for the current iterator positions */
+
+      for(i=0; i<pInfo->nPhrase; i++){
+        LcsIterator *pIter = &aIter[i];
+        if( pIter->pRead==0 ){
+          /* This iterator is already at EOF for this column. */
+          nThisLcs = 0;
+        }else{
+          if( pAdv==0 || pIter->iPos<pAdv->iPos ){
+            pAdv = pIter;
+          }
+          if( nThisLcs==0 || pIter->iPos==pIter[-1].iPos ){
+            nThisLcs++;
+          }else{
+            nThisLcs = 1;
+          }
+          if( nThisLcs>nLcs ) nLcs = nThisLcs;
+        }
+      }
+      if( fts3LcsIteratorAdvance(pAdv) ) nLive--;
+    }
+
+    pInfo->aMatchinfo[iCol] = nLcs;
+  }
+
+ matchinfo_lcs_out:
+  sqlite3_free(aIter);
+  return rc;
+}
+
+/*
+** Populate the buffer pInfo->aMatchinfo[] with an array of integers to
+** be returned by the matchinfo() function. Argument zArg contains the
+** format string passed as the second argument to matchinfo (or the
+** default value "pcx" if no second argument was specified). The format
+** string has already been validated and the pInfo->aMatchinfo[] array
+** is guaranteed to be large enough for the output.
+**
+** If bGlobal is true, then populate all fields of the matchinfo() output.
+** If it is false, then assume that those fields that do not change between
+** rows (i.e. FTS3_MATCHINFO_NPHRASE, NCOL, NDOC, AVGLENGTH and part of HITS)
+** have already been populated.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs. If a value other than SQLITE_OK is returned, the state the
+** pInfo->aMatchinfo[] buffer is left in is undefined.
+*/
+static int fts3MatchinfoValues(
+  Fts3Cursor *pCsr,               /* FTS3 cursor object */
+  int bGlobal,                    /* True to grab the global stats */
+  MatchInfo *pInfo,               /* Matchinfo context object */
+  const char *zArg                /* Matchinfo format string */
+){
+  int rc = SQLITE_OK;
+  int i;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  sqlite3_stmt *pSelect = 0;
+
+  for(i=0; rc==SQLITE_OK && zArg[i]; i++){
+    pInfo->flag = zArg[i];
+    switch( zArg[i] ){
+      case FTS3_MATCHINFO_NPHRASE:
+        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nPhrase;
+        break;
+
+      case FTS3_MATCHINFO_NCOL:
+        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nCol;
+        break;
+
+      case FTS3_MATCHINFO_NDOC:
+        if( bGlobal ){
+          sqlite3_int64 nDoc = 0;
+          rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &nDoc, 0, 0);
+          pInfo->aMatchinfo[0] = (u32)nDoc;
+        }
+        break;
+
+      case FTS3_MATCHINFO_AVGLENGTH:
+        if( bGlobal ){
+          sqlite3_int64 nDoc;     /* Number of rows in table */
+          const char *a;          /* Aggregate column length array */
+          const char *pEnd;       /* First byte past end of length array */
+
+          rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &nDoc, &a, &pEnd);
+          if( rc==SQLITE_OK ){
+            int iCol;
+            for(iCol=0; iCol<pInfo->nCol; iCol++){
+              u32 iVal;
+              sqlite3_int64 nToken;
+              a += sqlite3Fts3GetVarint(a, &nToken);
+              if( a>pEnd ){
+                rc = SQLITE_CORRUPT_VTAB;
+                break;
+              }
+              iVal = (u32)(((u32)(nToken&0xffffffff)+nDoc/2)/nDoc);
+              pInfo->aMatchinfo[iCol] = iVal;
+            }
+          }
+        }
+        break;
+
+      case FTS3_MATCHINFO_LENGTH: {
+        sqlite3_stmt *pSelectDocsize = 0;
+        rc = sqlite3Fts3SelectDocsize(pTab, pCsr->iPrevId, &pSelectDocsize);
+        if( rc==SQLITE_OK ){
+          int iCol;
+          const char *a = sqlite3_column_blob(pSelectDocsize, 0);
+          const char *pEnd = a + sqlite3_column_bytes(pSelectDocsize, 0);
+          for(iCol=0; iCol<pInfo->nCol; iCol++){
+            sqlite3_int64 nToken;
+            a += sqlite3Fts3GetVarintBounded(a, pEnd, &nToken);
+            if( a>pEnd ){
+              rc = SQLITE_CORRUPT_VTAB;
+              break;
+            }
+            pInfo->aMatchinfo[iCol] = (u32)nToken;
+          }
+        }
+        sqlite3_reset(pSelectDocsize);
+        break;
+      }
+
+      case FTS3_MATCHINFO_LCS:
+        rc = fts3ExprLoadDoclists(pCsr, 0, 0);
+        if( rc==SQLITE_OK ){
+          rc = fts3MatchinfoLcs(pCsr, pInfo);
+        }
+        break;
+
+      case FTS3_MATCHINFO_LHITS_BM:
+      case FTS3_MATCHINFO_LHITS: {
+        size_t nZero = fts3MatchinfoSize(pInfo, zArg[i]) * sizeof(u32);
+        memset(pInfo->aMatchinfo, 0, nZero);
+        rc = fts3ExprLHitGather(pCsr->pExpr, pInfo);
+        break;
+      }
+
+      default: {
+        Fts3Expr *pExpr;
+        assert( zArg[i]==FTS3_MATCHINFO_HITS );
+        pExpr = pCsr->pExpr;
+        rc = fts3ExprLoadDoclists(pCsr, 0, 0);
+        if( rc!=SQLITE_OK ) break;
+        if( bGlobal ){
+          if( pCsr->pDeferred ){
+            rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &pInfo->nDoc,0,0);
+            if( rc!=SQLITE_OK ) break;
+          }
+          rc = sqlite3Fts3ExprIterate(pExpr, fts3ExprGlobalHitsCb,(void*)pInfo);
+          sqlite3Fts3EvalTestDeferred(pCsr, &rc);
+          if( rc!=SQLITE_OK ) break;
+        }
+        (void)sqlite3Fts3ExprIterate(pExpr, fts3ExprLocalHitsCb,(void*)pInfo);
+        break;
+      }
+    }
+
+    pInfo->aMatchinfo += fts3MatchinfoSize(pInfo, zArg[i]);
+  }
+
+  sqlite3_reset(pSelect);
+  return rc;
+}
+
+
+/*
+** Populate pCsr->aMatchinfo[] with data for the current row. The
+** 'matchinfo' data is an array of 32-bit unsigned integers (C type u32).
+*/
+static void fts3GetMatchinfo(
+  sqlite3_context *pCtx,        /* Return results here */
+  Fts3Cursor *pCsr,               /* FTS3 Cursor object */
+  const char *zArg                /* Second argument to matchinfo() function */
+){
+  MatchInfo sInfo;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int bGlobal = 0;                /* Collect 'global' stats as well as local */
+
+  u32 *aOut = 0;
+  void (*xDestroyOut)(void*) = 0;
+
+  memset(&sInfo, 0, sizeof(MatchInfo));
+  sInfo.pCursor = pCsr;
+  sInfo.nCol = pTab->nColumn;
+
+  /* If there is cached matchinfo() data, but the format string for the
+  ** cache does not match the format string for this request, discard
+  ** the cached data. */
+  if( pCsr->pMIBuffer && strcmp(pCsr->pMIBuffer->zMatchinfo, zArg) ){
+    sqlite3Fts3MIBufferFree(pCsr->pMIBuffer);
+    pCsr->pMIBuffer = 0;
+  }
+
+  /* If Fts3Cursor.pMIBuffer is NULL, then this is the first time the
+  ** matchinfo function has been called for this query. In this case
+  ** allocate the array used to accumulate the matchinfo data and
+  ** initialize those elements that are constant for every row.
+  */
+  if( pCsr->pMIBuffer==0 ){
+    size_t nMatchinfo = 0;        /* Number of u32 elements in match-info */
+    int i;                        /* Used to iterate through zArg */
+
+    /* Determine the number of phrases in the query */
+    pCsr->nPhrase = fts3ExprPhraseCount(pCsr->pExpr);
+    sInfo.nPhrase = pCsr->nPhrase;
+
+    /* Determine the number of integers in the buffer returned by this call. */
+    for(i=0; zArg[i]; i++){
+      char *zErr = 0;
+      if( fts3MatchinfoCheck(pTab, zArg[i], &zErr) ){
+        sqlite3_result_error(pCtx, zErr, -1);
+        sqlite3_free(zErr);
+        return;
+      }
+      nMatchinfo += fts3MatchinfoSize(&sInfo, zArg[i]);
+    }
+
+    /* Allocate space for Fts3Cursor.aMatchinfo[] and Fts3Cursor.zMatchinfo. */
+    pCsr->pMIBuffer = fts3MIBufferNew(nMatchinfo, zArg);
+    if( !pCsr->pMIBuffer ) rc = SQLITE_NOMEM;
+
+    pCsr->isMatchinfoNeeded = 1;
+    bGlobal = 1;
+  }
+
+  if( rc==SQLITE_OK ){
+    xDestroyOut = fts3MIBufferAlloc(pCsr->pMIBuffer, &aOut);
+    if( xDestroyOut==0 ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sInfo.aMatchinfo = aOut;
+    sInfo.nPhrase = pCsr->nPhrase;
+    rc = fts3MatchinfoValues(pCsr, bGlobal, &sInfo, zArg);
+    if( bGlobal ){
+      fts3MIBufferSetGlobal(pCsr->pMIBuffer);
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+    if( xDestroyOut ) xDestroyOut(aOut);
+  }else{
+    int n = pCsr->pMIBuffer->nElem * sizeof(u32);
+    sqlite3_result_blob(pCtx, aOut, n, xDestroyOut);
+  }
+}
+
+/*
+** Implementation of snippet() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3Snippet(
+  sqlite3_context *pCtx,          /* SQLite function call context */
+  Fts3Cursor *pCsr,               /* Cursor object */
+  const char *zStart,             /* Snippet start text - "<b>" */
+  const char *zEnd,               /* Snippet end text - "</b>" */
+  const char *zEllipsis,          /* Snippet ellipsis text - "<b>...</b>" */
+  int iCol,                       /* Extract snippet from this column */
+  int nToken                      /* Approximate number of tokens in snippet */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int i;
+  StrBuffer res = {0, 0, 0};
+
+  /* The returned text includes up to four fragments of text extracted from
+  ** the data in the current row. The first iteration of the for(...) loop
+  ** below attempts to locate a single fragment of text nToken tokens in
+  ** size that contains at least one instance of all phrases in the query
+  ** expression that appear in the current row. If such a fragment of text
+  ** cannot be found, the second iteration of the loop attempts to locate
+  ** a pair of fragments, and so on.
+  */
+  int nSnippet = 0;               /* Number of fragments in this snippet */
+  SnippetFragment aSnippet[4];    /* Maximum of 4 fragments per snippet */
+  int nFToken = -1;               /* Number of tokens in each fragment */
+
+  if( !pCsr->pExpr ){
+    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
+    return;
+  }
+
+  /* Limit the snippet length to 64 tokens. */
+  if( nToken<-64 ) nToken = -64;
+  if( nToken>+64 ) nToken = +64;
+
+  for(nSnippet=1; 1; nSnippet++){
+
+    int iSnip;                    /* Loop counter 0..nSnippet-1 */
+    u64 mCovered = 0;             /* Bitmask of phrases covered by snippet */
+    u64 mSeen = 0;                /* Bitmask of phrases seen by BestSnippet() */
+
+    if( nToken>=0 ){
+      nFToken = (nToken+nSnippet-1) / nSnippet;
+    }else{
+      nFToken = -1 * nToken;
+    }
+
+    for(iSnip=0; iSnip<nSnippet; iSnip++){
+      int iBestScore = -1;        /* Best score of columns checked so far */
+      int iRead;                  /* Used to iterate through columns */
+      SnippetFragment *pFragment = &aSnippet[iSnip];
+
+      memset(pFragment, 0, sizeof(*pFragment));
+
+      /* Loop through all columns of the table being considered for snippets.
+      ** If the iCol argument to this function was negative, this means all
+      ** columns of the FTS3 table. Otherwise, only column iCol is considered.
+      */
+      for(iRead=0; iRead<pTab->nColumn; iRead++){
+        SnippetFragment sF = {0, 0, 0, 0};
+        int iS = 0;
+        if( iCol>=0 && iRead!=iCol ) continue;
+
+        /* Find the best snippet of nFToken tokens in column iRead. */
+        rc = fts3BestSnippet(nFToken, pCsr, iRead, mCovered, &mSeen, &sF, &iS);
+        if( rc!=SQLITE_OK ){
+          goto snippet_out;
+        }
+        if( iS>iBestScore ){
+          *pFragment = sF;
+          iBestScore = iS;
+        }
+      }
+
+      mCovered |= pFragment->covered;
+    }
+
+    /* If all query phrases seen by fts3BestSnippet() are present in at least
+    ** one of the nSnippet snippet fragments, break out of the loop.
+    */
+    assert( (mCovered&mSeen)==mCovered );
+    if( mSeen==mCovered || nSnippet==SizeofArray(aSnippet) ) break;
+  }
+
+  assert( nFToken>0 );
+
+  for(i=0; i<nSnippet && rc==SQLITE_OK; i++){
+    rc = fts3SnippetText(pCsr, &aSnippet[i],
+        i, (i==nSnippet-1), nFToken, zStart, zEnd, zEllipsis, &res
+    );
+  }
+
+ snippet_out:
+  sqlite3Fts3SegmentsClose(pTab);
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+    sqlite3_free(res.z);
+  }else{
+    sqlite3_result_text(pCtx, res.z, -1, sqlite3_free);
+  }
+}
+
+
+typedef struct TermOffset TermOffset;
+typedef struct TermOffsetCtx TermOffsetCtx;
+
+struct TermOffset {
+  char *pList;                    /* Position-list */
+  i64 iPos;                       /* Position just read from pList */
+  i64 iOff;                       /* Offset of this term from read positions */
+};
+
+struct TermOffsetCtx {
+  Fts3Cursor *pCsr;
+  int iCol;                       /* Column of table to populate aTerm for */
+  int iTerm;
+  sqlite3_int64 iDocid;
+  TermOffset *aTerm;
+};
+
+/*
+** This function is an sqlite3Fts3ExprIterate() callback used by sqlite3Fts3Offsets().
+*/
+static int fts3ExprTermOffsetInit(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  TermOffsetCtx *p = (TermOffsetCtx *)ctx;
+  int nTerm;                      /* Number of tokens in phrase */
+  int iTerm;                      /* For looping through nTerm phrase terms */
+  char *pList;                    /* Pointer to position list for phrase */
+  i64 iPos = 0;                   /* First position in position-list */
+  int rc;
+
+  UNUSED_PARAMETER(iPhrase);
+  rc = sqlite3Fts3EvalPhrasePoslist(p->pCsr, pExpr, p->iCol, &pList);
+  nTerm = pExpr->pPhrase->nToken;
+  if( pList ){
+    fts3GetDeltaPosition(&pList, &iPos);
+    assert_fts3_nc( iPos>=0 );
+  }
+
+  for(iTerm=0; iTerm<nTerm; iTerm++){
+    TermOffset *pT = &p->aTerm[p->iTerm++];
+    pT->iOff = nTerm-iTerm-1;
+    pT->pList = pList;
+    pT->iPos = iPos;
+  }
+
+  return rc;
+}
+
+/*
+** If expression pExpr is a phrase expression that uses an MSR query,
+** restart it as a regular, non-incremental query. Return SQLITE_OK
+** if successful, or an SQLite error code otherwise.
+*/
+static int fts3ExprRestartIfCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  TermOffsetCtx *p = (TermOffsetCtx*)ctx;
+  int rc = SQLITE_OK;
+  UNUSED_PARAMETER(iPhrase);
+  if( pExpr->pPhrase && pExpr->pPhrase->bIncr ){
+    rc = sqlite3Fts3MsrCancel(p->pCsr, pExpr);
+    pExpr->pPhrase->bIncr = 0;
+  }
+  return rc;
+}
+
+/*
+** Implementation of offsets() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3Offsets(
+  sqlite3_context *pCtx,          /* SQLite function call context */
+  Fts3Cursor *pCsr                /* Cursor object */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  sqlite3_tokenizer_module const *pMod = pTab->pTokenizer->pModule;
+  int rc;                         /* Return Code */
+  int nToken;                     /* Number of tokens in query */
+  int iCol;                       /* Column currently being processed */
+  StrBuffer res = {0, 0, 0};      /* Result string */
+  TermOffsetCtx sCtx;             /* Context for fts3ExprTermOffsetInit() */
+
+  if( !pCsr->pExpr ){
+    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
+    return;
+  }
+
+  memset(&sCtx, 0, sizeof(sCtx));
+  assert( pCsr->isRequireSeek==0 );
+
+  /* Count the number of terms in the query */
+  rc = fts3ExprLoadDoclists(pCsr, 0, &nToken);
+  if( rc!=SQLITE_OK ) goto offsets_out;
+
+  /* Allocate the array of TermOffset iterators. */
+  sCtx.aTerm = (TermOffset *)sqlite3Fts3MallocZero(sizeof(TermOffset)*nToken);
+  if( 0==sCtx.aTerm ){
+    rc = SQLITE_NOMEM;
+    goto offsets_out;
+  }
+  sCtx.iDocid = pCsr->iPrevId;
+  sCtx.pCsr = pCsr;
+
+  /* If a query restart will be required, do it here, rather than later of
+  ** after pointers to poslist buffers that may be invalidated by a restart
+  ** have been saved.  */
+  rc = sqlite3Fts3ExprIterate(pCsr->pExpr, fts3ExprRestartIfCb, (void*)&sCtx);
+  if( rc!=SQLITE_OK ) goto offsets_out;
+
+  /* Loop through the table columns, appending offset information to
+  ** string-buffer res for each column.
+  */
+  for(iCol=0; iCol<pTab->nColumn; iCol++){
+    sqlite3_tokenizer_cursor *pC; /* Tokenizer cursor */
+    const char *ZDUMMY;           /* Dummy argument used with xNext() */
+    int NDUMMY = 0;               /* Dummy argument used with xNext() */
+    int iStart = 0;
+    int iEnd = 0;
+    int iCurrent = 0;
+    const char *zDoc;
+    int nDoc;
+
+    /* Initialize the contents of sCtx.aTerm[] for column iCol. This
+    ** operation may fail if the database contains corrupt records.
+    */
+    sCtx.iCol = iCol;
+    sCtx.iTerm = 0;
+    rc = sqlite3Fts3ExprIterate(
+        pCsr->pExpr, fts3ExprTermOffsetInit, (void*)&sCtx
+    );
+    if( rc!=SQLITE_OK ) goto offsets_out;
+
+    /* Retreive the text stored in column iCol. If an SQL NULL is stored
+    ** in column iCol, jump immediately to the next iteration of the loop.
+    ** If an OOM occurs while retrieving the data (this can happen if SQLite
+    ** needs to transform the data from utf-16 to utf-8), return SQLITE_NOMEM
+    ** to the caller.
+    */
+    zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol+1);
+    nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol+1);
+    if( zDoc==0 ){
+      if( sqlite3_column_type(pCsr->pStmt, iCol+1)==SQLITE_NULL ){
+        continue;
+      }
+      rc = SQLITE_NOMEM;
+      goto offsets_out;
+    }
+
+    /* Initialize a tokenizer iterator to iterate through column iCol. */
+    rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, pCsr->iLangid,
+        zDoc, nDoc, &pC
+    );
+    if( rc!=SQLITE_OK ) goto offsets_out;
+
+    rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
+    while( rc==SQLITE_OK ){
+      int i;                      /* Used to loop through terms */
+      int iMinPos = 0x7FFFFFFF;   /* Position of next token */
+      TermOffset *pTerm = 0;      /* TermOffset associated with next token */
+
+      for(i=0; i<nToken; i++){
+        TermOffset *pT = &sCtx.aTerm[i];
+        if( pT->pList && (pT->iPos-pT->iOff)<iMinPos ){
+          iMinPos = pT->iPos-pT->iOff;
+          pTerm = pT;
+        }
+      }
+
+      if( !pTerm ){
+        /* All offsets for this column have been gathered. */
+        rc = SQLITE_DONE;
+      }else{
+        assert_fts3_nc( iCurrent<=iMinPos );
+        if( 0==(0xFE&*pTerm->pList) ){
+          pTerm->pList = 0;
+        }else{
+          fts3GetDeltaPosition(&pTerm->pList, &pTerm->iPos);
+        }
+        while( rc==SQLITE_OK && iCurrent<iMinPos ){
+          rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
+        }
+        if( rc==SQLITE_OK ){
+          char aBuffer[64];
+          sqlite3_snprintf(sizeof(aBuffer), aBuffer,
+              "%d %d %d %d ", iCol, pTerm-sCtx.aTerm, iStart, iEnd-iStart
+          );
+          rc = fts3StringAppend(&res, aBuffer, -1);
+        }else if( rc==SQLITE_DONE && pTab->zContentTbl==0 ){
+          rc = FTS_CORRUPT_VTAB;
+        }
+      }
+    }
+    if( rc==SQLITE_DONE ){
+      rc = SQLITE_OK;
+    }
+
+    pMod->xClose(pC);
+    if( rc!=SQLITE_OK ) goto offsets_out;
+  }
+
+ offsets_out:
+  sqlite3_free(sCtx.aTerm);
+  assert( rc!=SQLITE_DONE );
+  sqlite3Fts3SegmentsClose(pTab);
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx,  rc);
+    sqlite3_free(res.z);
+  }else{
+    sqlite3_result_text(pCtx, res.z, res.n-1, sqlite3_free);
+  }
+  return;
+}
+
+/*
+** Implementation of matchinfo() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3Matchinfo(
+  sqlite3_context *pContext,      /* Function call context */
+  Fts3Cursor *pCsr,               /* FTS3 table cursor */
+  const char *zArg                /* Second arg to matchinfo() function */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  const char *zFormat;
+
+  if( zArg ){
+    zFormat = zArg;
+  }else{
+    zFormat = FTS3_MATCHINFO_DEFAULT;
+  }
+
+  if( !pCsr->pExpr ){
+    sqlite3_result_blob(pContext, "", 0, SQLITE_STATIC);
+    return;
+  }else{
+    /* Retrieve matchinfo() data. */
+    fts3GetMatchinfo(pContext, pCsr, zFormat);
+    sqlite3Fts3SegmentsClose(pTab);
+  }
+}
+
+#endif
+
+/************** End of fts3_snippet.c ****************************************/
+/************** Begin file fts3_unicode.c ************************************/
+/*
+** 2012 May 24
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Implementation of the "unicode" full-text-search tokenizer.
+*/
+
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+
+/* #include "fts3_tokenizer.h" */
+
+/*
+** The following two macros - READ_UTF8 and WRITE_UTF8 - have been copied
+** from the sqlite3 source file utf.c. If this file is compiled as part
+** of the amalgamation, they are not required.
+*/
+#ifndef SQLITE_AMALGAMATION
+
+static const unsigned char sqlite3Utf8Trans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+#define READ_UTF8(zIn, zTerm, c)                           \
+  c = *(zIn++);                                            \
+  if( c>=0xc0 ){                                           \
+    c = sqlite3Utf8Trans1[c-0xc0];                         \
+    while( zIn!=zTerm && (*zIn & 0xc0)==0x80 ){            \
+      c = (c<<6) + (0x3f & *(zIn++));                      \
+    }                                                      \
+    if( c<0x80                                             \
+        || (c&0xFFFFF800)==0xD800                          \
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }        \
+  }
+
+#define WRITE_UTF8(zOut, c) {                          \
+  if( c<0x00080 ){                                     \
+    *zOut++ = (u8)(c&0xFF);                            \
+  }                                                    \
+  else if( c<0x00800 ){                                \
+    *zOut++ = 0xC0 + (u8)((c>>6)&0x1F);                \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+  else if( c<0x10000 ){                                \
+    *zOut++ = 0xE0 + (u8)((c>>12)&0x0F);               \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }else{                                               \
+    *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);             \
+    *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);             \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+}
+
+#endif /* ifndef SQLITE_AMALGAMATION */
+
+typedef struct unicode_tokenizer unicode_tokenizer;
+typedef struct unicode_cursor unicode_cursor;
+
+struct unicode_tokenizer {
+  sqlite3_tokenizer base;
+  int eRemoveDiacritic;
+  int nException;
+  int *aiException;
+};
+
+struct unicode_cursor {
+  sqlite3_tokenizer_cursor base;
+  const unsigned char *aInput;    /* Input text being tokenized */
+  int nInput;                     /* Size of aInput[] in bytes */
+  int iOff;                       /* Current offset within aInput[] */
+  int iToken;                     /* Index of next token to be returned */
+  char *zToken;                   /* storage for current token */
+  int nAlloc;                     /* space allocated at zToken */
+};
+
+
+/*
+** Destroy a tokenizer allocated by unicodeCreate().
+*/
+static int unicodeDestroy(sqlite3_tokenizer *pTokenizer){
+  if( pTokenizer ){
+    unicode_tokenizer *p = (unicode_tokenizer *)pTokenizer;
+    sqlite3_free(p->aiException);
+    sqlite3_free(p);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** As part of a tokenchars= or separators= option, the CREATE VIRTUAL TABLE
+** statement has specified that the tokenizer for this table shall consider
+** all characters in string zIn/nIn to be separators (if bAlnum==0) or
+** token characters (if bAlnum==1).
+**
+** For each codepoint in the zIn/nIn string, this function checks if the
+** sqlite3FtsUnicodeIsalnum() function already returns the desired result.
+** If so, no action is taken. Otherwise, the codepoint is added to the
+** unicode_tokenizer.aiException[] array. For the purposes of tokenization,
+** the return value of sqlite3FtsUnicodeIsalnum() is inverted for all
+** codepoints in the aiException[] array.
+**
+** If a standalone diacritic mark (one that sqlite3FtsUnicodeIsdiacritic()
+** identifies as a diacritic) occurs in the zIn/nIn string it is ignored.
+** It is not possible to change the behavior of the tokenizer with respect
+** to these codepoints.
+*/
+static int unicodeAddExceptions(
+  unicode_tokenizer *p,           /* Tokenizer to add exceptions to */
+  int bAlnum,                     /* Replace Isalnum() return value with this */
+  const char *zIn,                /* Array of characters to make exceptions */
+  int nIn                         /* Length of z in bytes */
+){
+  const unsigned char *z = (const unsigned char *)zIn;
+  const unsigned char *zTerm = &z[nIn];
+  unsigned int iCode;
+  int nEntry = 0;
+
+  assert( bAlnum==0 || bAlnum==1 );
+
+  while( z<zTerm ){
+    READ_UTF8(z, zTerm, iCode);
+    assert( (sqlite3FtsUnicodeIsalnum((int)iCode) & 0xFFFFFFFE)==0 );
+    if( sqlite3FtsUnicodeIsalnum((int)iCode)!=bAlnum
+     && sqlite3FtsUnicodeIsdiacritic((int)iCode)==0
+    ){
+      nEntry++;
+    }
+  }
+
+  if( nEntry ){
+    int *aNew;                    /* New aiException[] array */
+    int nNew;                     /* Number of valid entries in array aNew[] */
+
+    aNew = sqlite3_realloc64(p->aiException,(p->nException+nEntry)*sizeof(int));
+    if( aNew==0 ) return SQLITE_NOMEM;
+    nNew = p->nException;
+
+    z = (const unsigned char *)zIn;
+    while( z<zTerm ){
+      READ_UTF8(z, zTerm, iCode);
+      if( sqlite3FtsUnicodeIsalnum((int)iCode)!=bAlnum
+       && sqlite3FtsUnicodeIsdiacritic((int)iCode)==0
+      ){
+        int i, j;
+        for(i=0; i<nNew && aNew[i]<(int)iCode; i++);
+        for(j=nNew; j>i; j--) aNew[j] = aNew[j-1];
+        aNew[i] = (int)iCode;
+        nNew++;
+      }
+    }
+    p->aiException = aNew;
+    p->nException = nNew;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Return true if the p->aiException[] array contains the value iCode.
+*/
+static int unicodeIsException(unicode_tokenizer *p, int iCode){
+  if( p->nException>0 ){
+    int *a = p->aiException;
+    int iLo = 0;
+    int iHi = p->nException-1;
+
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      if( iCode==a[iTest] ){
+        return 1;
+      }else if( iCode>a[iTest] ){
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Return true if, for the purposes of tokenization, codepoint iCode is
+** considered a token character (not a separator).
+*/
+static int unicodeIsAlnum(unicode_tokenizer *p, int iCode){
+  assert( (sqlite3FtsUnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 );
+  return sqlite3FtsUnicodeIsalnum(iCode) ^ unicodeIsException(p, iCode);
+}
+
+/*
+** Create a new tokenizer instance.
+*/
+static int unicodeCreate(
+  int nArg,                       /* Size of array argv[] */
+  const char * const *azArg,      /* Tokenizer creation arguments */
+  sqlite3_tokenizer **pp          /* OUT: New tokenizer handle */
+){
+  unicode_tokenizer *pNew;        /* New tokenizer object */
+  int i;
+  int rc = SQLITE_OK;
+
+  pNew = (unicode_tokenizer *) sqlite3_malloc(sizeof(unicode_tokenizer));
+  if( pNew==NULL ) return SQLITE_NOMEM;
+  memset(pNew, 0, sizeof(unicode_tokenizer));
+  pNew->eRemoveDiacritic = 1;
+
+  for(i=0; rc==SQLITE_OK && i<nArg; i++){
+    const char *z = azArg[i];
+    int n = (int)strlen(z);
+
+    if( n==19 && memcmp("remove_diacritics=1", z, 19)==0 ){
+      pNew->eRemoveDiacritic = 1;
+    }
+    else if( n==19 && memcmp("remove_diacritics=0", z, 19)==0 ){
+      pNew->eRemoveDiacritic = 0;
+    }
+    else if( n==19 && memcmp("remove_diacritics=2", z, 19)==0 ){
+      pNew->eRemoveDiacritic = 2;
+    }
+    else if( n>=11 && memcmp("tokenchars=", z, 11)==0 ){
+      rc = unicodeAddExceptions(pNew, 1, &z[11], n-11);
+    }
+    else if( n>=11 && memcmp("separators=", z, 11)==0 ){
+      rc = unicodeAddExceptions(pNew, 0, &z[11], n-11);
+    }
+    else{
+      /* Unrecognized argument */
+      rc  = SQLITE_ERROR;
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    unicodeDestroy((sqlite3_tokenizer *)pNew);
+    pNew = 0;
+  }
+  *pp = (sqlite3_tokenizer *)pNew;
+  return rc;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is pInput[0..nBytes-1].  A cursor
+** used to incrementally tokenize this string is returned in
+** *ppCursor.
+*/
+static int unicodeOpen(
+  sqlite3_tokenizer *p,           /* The tokenizer */
+  const char *aInput,             /* Input string */
+  int nInput,                     /* Size of string aInput in bytes */
+  sqlite3_tokenizer_cursor **pp   /* OUT: New cursor object */
+){
+  unicode_cursor *pCsr;
+
+  pCsr = (unicode_cursor *)sqlite3_malloc(sizeof(unicode_cursor));
+  if( pCsr==0 ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(unicode_cursor));
+
+  pCsr->aInput = (const unsigned char *)aInput;
+  if( aInput==0 ){
+    pCsr->nInput = 0;
+    pCsr->aInput = (const unsigned char*)"";
+  }else if( nInput<0 ){
+    pCsr->nInput = (int)strlen(aInput);
+  }else{
+    pCsr->nInput = nInput;
+  }
+
+  *pp = &pCsr->base;
+  UNUSED_PARAMETER(p);
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to
+** simpleOpen() above.
+*/
+static int unicodeClose(sqlite3_tokenizer_cursor *pCursor){
+  unicode_cursor *pCsr = (unicode_cursor *) pCursor;
+  sqlite3_free(pCsr->zToken);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** Extract the next token from a tokenization cursor.  The cursor must
+** have been opened by a prior call to simpleOpen().
+*/
+static int unicodeNext(
+  sqlite3_tokenizer_cursor *pC,   /* Cursor returned by simpleOpen */
+  const char **paToken,           /* OUT: Token text */
+  int *pnToken,                   /* OUT: Number of bytes at *paToken */
+  int *piStart,                   /* OUT: Starting offset of token */
+  int *piEnd,                     /* OUT: Ending offset of token */
+  int *piPos                      /* OUT: Position integer of token */
+){
+  unicode_cursor *pCsr = (unicode_cursor *)pC;
+  unicode_tokenizer *p = ((unicode_tokenizer *)pCsr->base.pTokenizer);
+  unsigned int iCode = 0;
+  char *zOut;
+  const unsigned char *z = &pCsr->aInput[pCsr->iOff];
+  const unsigned char *zStart = z;
+  const unsigned char *zEnd;
+  const unsigned char *zTerm = &pCsr->aInput[pCsr->nInput];
+
+  /* Scan past any delimiter characters before the start of the next token.
+  ** Return SQLITE_DONE early if this takes us all the way to the end of
+  ** the input.  */
+  while( z<zTerm ){
+    READ_UTF8(z, zTerm, iCode);
+    if( unicodeIsAlnum(p, (int)iCode) ) break;
+    zStart = z;
+  }
+  if( zStart>=zTerm ) return SQLITE_DONE;
+
+  zOut = pCsr->zToken;
+  do {
+    int iOut;
+
+    /* Grow the output buffer if required. */
+    if( (zOut-pCsr->zToken)>=(pCsr->nAlloc-4) ){
+      char *zNew = sqlite3_realloc64(pCsr->zToken, pCsr->nAlloc+64);
+      if( !zNew ) return SQLITE_NOMEM;
+      zOut = &zNew[zOut - pCsr->zToken];
+      pCsr->zToken = zNew;
+      pCsr->nAlloc += 64;
+    }
+
+    /* Write the folded case of the last character read to the output */
+    zEnd = z;
+    iOut = sqlite3FtsUnicodeFold((int)iCode, p->eRemoveDiacritic);
+    if( iOut ){
+      WRITE_UTF8(zOut, iOut);
+    }
+
+    /* If the cursor is not at EOF, read the next character */
+    if( z>=zTerm ) break;
+    READ_UTF8(z, zTerm, iCode);
+  }while( unicodeIsAlnum(p, (int)iCode)
+       || sqlite3FtsUnicodeIsdiacritic((int)iCode)
+  );
+
+  /* Set the output variables and return. */
+  pCsr->iOff = (int)(z - pCsr->aInput);
+  *paToken = pCsr->zToken;
+  *pnToken = (int)(zOut - pCsr->zToken);
+  *piStart = (int)(zStart - pCsr->aInput);
+  *piEnd = (int)(zEnd - pCsr->aInput);
+  *piPos = pCsr->iToken++;
+  return SQLITE_OK;
+}
+
+/*
+** Set *ppModule to a pointer to the sqlite3_tokenizer_module
+** structure for the unicode tokenizer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const **ppModule){
+  static const sqlite3_tokenizer_module module = {
+    0,
+    unicodeCreate,
+    unicodeDestroy,
+    unicodeOpen,
+    unicodeClose,
+    unicodeNext,
+    0,
+  };
+  *ppModule = &module;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+#endif /* ifndef SQLITE_DISABLE_FTS3_UNICODE */
+
+/************** End of fts3_unicode.c ****************************************/
+/************** Begin file fts3_unicode2.c ***********************************/
+/*
+** 2012-05-25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+/*
+** DO NOT EDIT THIS MACHINE GENERATED FILE.
+*/
+
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
+
+/* #include <assert.h> */
+
+/*
+** Return true if the argument corresponds to a unicode codepoint
+** classified as either a letter or a number. Otherwise false.
+**
+** The results are undefined if the value passed to this function
+** is less than zero.
+*/
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsalnum(int c){
+  /* Each unsigned integer in the following array corresponds to a contiguous
+  ** range of unicode codepoints that are not either letters or numbers (i.e.
+  ** codepoints for which this function should return 0).
+  **
+  ** The most significant 22 bits in each 32-bit value contain the first
+  ** codepoint in the range. The least significant 10 bits are used to store
+  ** the size of the range (always at least 1). In other words, the value
+  ** ((C<<22) + N) represents a range of N codepoints starting with codepoint
+  ** C. It is not possible to represent a range larger than 1023 codepoints
+  ** using this format.
+  */
+  static const unsigned int aEntry[] = {
+    0x00000030, 0x0000E807, 0x00016C06, 0x0001EC2F, 0x0002AC07,
+    0x0002D001, 0x0002D803, 0x0002EC01, 0x0002FC01, 0x00035C01,
+    0x0003DC01, 0x000B0804, 0x000B480E, 0x000B9407, 0x000BB401,
+    0x000BBC81, 0x000DD401, 0x000DF801, 0x000E1002, 0x000E1C01,
+    0x000FD801, 0x00120808, 0x00156806, 0x00162402, 0x00163C01,
+    0x00164437, 0x0017CC02, 0x00180005, 0x00181816, 0x00187802,
+    0x00192C15, 0x0019A804, 0x0019C001, 0x001B5001, 0x001B580F,
+    0x001B9C07, 0x001BF402, 0x001C000E, 0x001C3C01, 0x001C4401,
+    0x001CC01B, 0x001E980B, 0x001FAC09, 0x001FD804, 0x00205804,
+    0x00206C09, 0x00209403, 0x0020A405, 0x0020C00F, 0x00216403,
+    0x00217801, 0x0023901B, 0x00240004, 0x0024E803, 0x0024F812,
+    0x00254407, 0x00258804, 0x0025C001, 0x00260403, 0x0026F001,
+    0x0026F807, 0x00271C02, 0x00272C03, 0x00275C01, 0x00278802,
+    0x0027C802, 0x0027E802, 0x00280403, 0x0028F001, 0x0028F805,
+    0x00291C02, 0x00292C03, 0x00294401, 0x0029C002, 0x0029D401,
+    0x002A0403, 0x002AF001, 0x002AF808, 0x002B1C03, 0x002B2C03,
+    0x002B8802, 0x002BC002, 0x002C0403, 0x002CF001, 0x002CF807,
+    0x002D1C02, 0x002D2C03, 0x002D5802, 0x002D8802, 0x002DC001,
+    0x002E0801, 0x002EF805, 0x002F1803, 0x002F2804, 0x002F5C01,
+    0x002FCC08, 0x00300403, 0x0030F807, 0x00311803, 0x00312804,
+    0x00315402, 0x00318802, 0x0031FC01, 0x00320802, 0x0032F001,
+    0x0032F807, 0x00331803, 0x00332804, 0x00335402, 0x00338802,
+    0x00340802, 0x0034F807, 0x00351803, 0x00352804, 0x00355C01,
+    0x00358802, 0x0035E401, 0x00360802, 0x00372801, 0x00373C06,
+    0x00375801, 0x00376008, 0x0037C803, 0x0038C401, 0x0038D007,
+    0x0038FC01, 0x00391C09, 0x00396802, 0x003AC401, 0x003AD006,
+    0x003AEC02, 0x003B2006, 0x003C041F, 0x003CD00C, 0x003DC417,
+    0x003E340B, 0x003E6424, 0x003EF80F, 0x003F380D, 0x0040AC14,
+    0x00412806, 0x00415804, 0x00417803, 0x00418803, 0x00419C07,
+    0x0041C404, 0x0042080C, 0x00423C01, 0x00426806, 0x0043EC01,
+    0x004D740C, 0x004E400A, 0x00500001, 0x0059B402, 0x005A0001,
+    0x005A6C02, 0x005BAC03, 0x005C4803, 0x005CC805, 0x005D4802,
+    0x005DC802, 0x005ED023, 0x005F6004, 0x005F7401, 0x0060000F,
+    0x0062A401, 0x0064800C, 0x0064C00C, 0x00650001, 0x00651002,
+    0x0066C011, 0x00672002, 0x00677822, 0x00685C05, 0x00687802,
+    0x0069540A, 0x0069801D, 0x0069FC01, 0x006A8007, 0x006AA006,
+    0x006C0005, 0x006CD011, 0x006D6823, 0x006E0003, 0x006E840D,
+    0x006F980E, 0x006FF004, 0x00709014, 0x0070EC05, 0x0071F802,
+    0x00730008, 0x00734019, 0x0073B401, 0x0073C803, 0x00770027,
+    0x0077F004, 0x007EF401, 0x007EFC03, 0x007F3403, 0x007F7403,
+    0x007FB403, 0x007FF402, 0x00800065, 0x0081A806, 0x0081E805,
+    0x00822805, 0x0082801A, 0x00834021, 0x00840002, 0x00840C04,
+    0x00842002, 0x00845001, 0x00845803, 0x00847806, 0x00849401,
+    0x00849C01, 0x0084A401, 0x0084B801, 0x0084E802, 0x00850005,
+    0x00852804, 0x00853C01, 0x00864264, 0x00900027, 0x0091000B,
+    0x0092704E, 0x00940200, 0x009C0475, 0x009E53B9, 0x00AD400A,
+    0x00B39406, 0x00B3BC03, 0x00B3E404, 0x00B3F802, 0x00B5C001,
+    0x00B5FC01, 0x00B7804F, 0x00B8C00C, 0x00BA001A, 0x00BA6C59,
+    0x00BC00D6, 0x00BFC00C, 0x00C00005, 0x00C02019, 0x00C0A807,
+    0x00C0D802, 0x00C0F403, 0x00C26404, 0x00C28001, 0x00C3EC01,
+    0x00C64002, 0x00C6580A, 0x00C70024, 0x00C8001F, 0x00C8A81E,
+    0x00C94001, 0x00C98020, 0x00CA2827, 0x00CB003F, 0x00CC0100,
+    0x01370040, 0x02924037, 0x0293F802, 0x02983403, 0x0299BC10,
+    0x029A7C01, 0x029BC008, 0x029C0017, 0x029C8002, 0x029E2402,
+    0x02A00801, 0x02A01801, 0x02A02C01, 0x02A08C09, 0x02A0D804,
+    0x02A1D004, 0x02A20002, 0x02A2D011, 0x02A33802, 0x02A38012,
+    0x02A3E003, 0x02A4980A, 0x02A51C0D, 0x02A57C01, 0x02A60004,
+    0x02A6CC1B, 0x02A77802, 0x02A8A40E, 0x02A90C01, 0x02A93002,
+    0x02A97004, 0x02A9DC03, 0x02A9EC01, 0x02AAC001, 0x02AAC803,
+    0x02AADC02, 0x02AAF802, 0x02AB0401, 0x02AB7802, 0x02ABAC07,
+    0x02ABD402, 0x02AF8C0B, 0x03600001, 0x036DFC02, 0x036FFC02,
+    0x037FFC01, 0x03EC7801, 0x03ECA401, 0x03EEC810, 0x03F4F802,
+    0x03F7F002, 0x03F8001A, 0x03F88007, 0x03F8C023, 0x03F95013,
+    0x03F9A004, 0x03FBFC01, 0x03FC040F, 0x03FC6807, 0x03FCEC06,
+    0x03FD6C0B, 0x03FF8007, 0x03FFA007, 0x03FFE405, 0x04040003,
+    0x0404DC09, 0x0405E411, 0x0406400C, 0x0407402E, 0x040E7C01,
+    0x040F4001, 0x04215C01, 0x04247C01, 0x0424FC01, 0x04280403,
+    0x04281402, 0x04283004, 0x0428E003, 0x0428FC01, 0x04294009,
+    0x0429FC01, 0x042CE407, 0x04400003, 0x0440E016, 0x04420003,
+    0x0442C012, 0x04440003, 0x04449C0E, 0x04450004, 0x04460003,
+    0x0446CC0E, 0x04471404, 0x045AAC0D, 0x0491C004, 0x05BD442E,
+    0x05BE3C04, 0x074000F6, 0x07440027, 0x0744A4B5, 0x07480046,
+    0x074C0057, 0x075B0401, 0x075B6C01, 0x075BEC01, 0x075C5401,
+    0x075CD401, 0x075D3C01, 0x075DBC01, 0x075E2401, 0x075EA401,
+    0x075F0C01, 0x07BBC002, 0x07C0002C, 0x07C0C064, 0x07C2800F,
+    0x07C2C40E, 0x07C3040F, 0x07C3440F, 0x07C4401F, 0x07C4C03C,
+    0x07C5C02B, 0x07C7981D, 0x07C8402B, 0x07C90009, 0x07C94002,
+    0x07CC0021, 0x07CCC006, 0x07CCDC46, 0x07CE0014, 0x07CE8025,
+    0x07CF1805, 0x07CF8011, 0x07D0003F, 0x07D10001, 0x07D108B6,
+    0x07D3E404, 0x07D4003E, 0x07D50004, 0x07D54018, 0x07D7EC46,
+    0x07D9140B, 0x07DA0046, 0x07DC0074, 0x38000401, 0x38008060,
+    0x380400F0,
+  };
+  static const unsigned int aAscii[4] = {
+    0xFFFFFFFF, 0xFC00FFFF, 0xF8000001, 0xF8000001,
+  };
+
+  if( (unsigned int)c<128 ){
+    return ( (aAscii[c >> 5] & ((unsigned int)1 << (c & 0x001F)))==0 );
+  }else if( (unsigned int)c<(1<<22) ){
+    unsigned int key = (((unsigned int)c)<<10) | 0x000003FF;
+    int iRes = 0;
+    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
+    int iLo = 0;
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      if( key >= aEntry[iTest] ){
+        iRes = iTest;
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+    assert( aEntry[0]<key );
+    assert( key>=aEntry[iRes] );
+    return (((unsigned int)c) >= ((aEntry[iRes]>>10) + (aEntry[iRes]&0x3FF)));
+  }
+  return 1;
+}
+
+
+/*
+** If the argument is a codepoint corresponding to a lowercase letter
+** in the ASCII range with a diacritic added, return the codepoint
+** of the ASCII letter only. For example, if passed 235 - "LATIN
+** SMALL LETTER E WITH DIAERESIS" - return 65 ("LATIN SMALL LETTER
+** E"). The resuls of passing a codepoint that corresponds to an
+** uppercase letter are undefined.
+*/
+static int remove_diacritic(int c, int bComplex){
+  unsigned short aDia[] = {
+        0,  1797,  1848,  1859,  1891,  1928,  1940,  1995,
+     2024,  2040,  2060,  2110,  2168,  2206,  2264,  2286,
+     2344,  2383,  2472,  2488,  2516,  2596,  2668,  2732,
+     2782,  2842,  2894,  2954,  2984,  3000,  3028,  3336,
+     3456,  3696,  3712,  3728,  3744,  3766,  3832,  3896,
+     3912,  3928,  3944,  3968,  4008,  4040,  4056,  4106,
+     4138,  4170,  4202,  4234,  4266,  4296,  4312,  4344,
+     4408,  4424,  4442,  4472,  4488,  4504,  6148,  6198,
+     6264,  6280,  6360,  6429,  6505,  6529, 61448, 61468,
+    61512, 61534, 61592, 61610, 61642, 61672, 61688, 61704,
+    61726, 61784, 61800, 61816, 61836, 61880, 61896, 61914,
+    61948, 61998, 62062, 62122, 62154, 62184, 62200, 62218,
+    62252, 62302, 62364, 62410, 62442, 62478, 62536, 62554,
+    62584, 62604, 62640, 62648, 62656, 62664, 62730, 62766,
+    62830, 62890, 62924, 62974, 63032, 63050, 63082, 63118,
+    63182, 63242, 63274, 63310, 63368, 63390,
+  };
+#define HIBIT ((unsigned char)0x80)
+  unsigned char aChar[] = {
+    '\0',      'a',       'c',       'e',       'i',       'n',
+    'o',       'u',       'y',       'y',       'a',       'c',
+    'd',       'e',       'e',       'g',       'h',       'i',
+    'j',       'k',       'l',       'n',       'o',       'r',
+    's',       't',       'u',       'u',       'w',       'y',
+    'z',       'o',       'u',       'a',       'i',       'o',
+    'u',       'u'|HIBIT, 'a'|HIBIT, 'g',       'k',       'o',
+    'o'|HIBIT, 'j',       'g',       'n',       'a'|HIBIT, 'a',
+    'e',       'i',       'o',       'r',       'u',       's',
+    't',       'h',       'a',       'e',       'o'|HIBIT, 'o',
+    'o'|HIBIT, 'y',       '\0',      '\0',      '\0',      '\0',
+    '\0',      '\0',      '\0',      '\0',      'a',       'b',
+    'c'|HIBIT, 'd',       'd',       'e'|HIBIT, 'e',       'e'|HIBIT,
+    'f',       'g',       'h',       'h',       'i',       'i'|HIBIT,
+    'k',       'l',       'l'|HIBIT, 'l',       'm',       'n',
+    'o'|HIBIT, 'p',       'r',       'r'|HIBIT, 'r',       's',
+    's'|HIBIT, 't',       'u',       'u'|HIBIT, 'v',       'w',
+    'w',       'x',       'y',       'z',       'h',       't',
+    'w',       'y',       'a',       'a'|HIBIT, 'a'|HIBIT, 'a'|HIBIT,
+    'e',       'e'|HIBIT, 'e'|HIBIT, 'i',       'o',       'o'|HIBIT,
+    'o'|HIBIT, 'o'|HIBIT, 'u',       'u'|HIBIT, 'u'|HIBIT, 'y',
+  };
+
+  unsigned int key = (((unsigned int)c)<<3) | 0x00000007;
+  int iRes = 0;
+  int iHi = sizeof(aDia)/sizeof(aDia[0]) - 1;
+  int iLo = 0;
+  while( iHi>=iLo ){
+    int iTest = (iHi + iLo) / 2;
+    if( key >= aDia[iTest] ){
+      iRes = iTest;
+      iLo = iTest+1;
+    }else{
+      iHi = iTest-1;
+    }
+  }
+  assert( key>=aDia[iRes] );
+  if( bComplex==0 && (aChar[iRes] & 0x80) ) return c;
+  return (c > (aDia[iRes]>>3) + (aDia[iRes]&0x07)) ? c : ((int)aChar[iRes] & 0x7F);
+}
+
+
+/*
+** Return true if the argument interpreted as a unicode codepoint
+** is a diacritical modifier character.
+*/
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsdiacritic(int c){
+  unsigned int mask0 = 0x08029FDF;
+  unsigned int mask1 = 0x000361F8;
+  if( c<768 || c>817 ) return 0;
+  return (c < 768+32) ?
+      (mask0 & ((unsigned int)1 << (c-768))) :
+      (mask1 & ((unsigned int)1 << (c-768-32)));
+}
+
+
+/*
+** Interpret the argument as a unicode codepoint. If the codepoint
+** is an upper case character that has a lower case equivalent,
+** return the codepoint corresponding to the lower case version.
+** Otherwise, return a copy of the argument.
+**
+** The results are undefined if the value passed to this function
+** is less than zero.
+*/
+SQLITE_PRIVATE int sqlite3FtsUnicodeFold(int c, int eRemoveDiacritic){
+  /* Each entry in the following array defines a rule for folding a range
+  ** of codepoints to lower case. The rule applies to a range of nRange
+  ** codepoints starting at codepoint iCode.
+  **
+  ** If the least significant bit in flags is clear, then the rule applies
+  ** to all nRange codepoints (i.e. all nRange codepoints are upper case and
+  ** need to be folded). Or, if it is set, then the rule only applies to
+  ** every second codepoint in the range, starting with codepoint C.
+  **
+  ** The 7 most significant bits in flags are an index into the aiOff[]
+  ** array. If a specific codepoint C does require folding, then its lower
+  ** case equivalent is ((C + aiOff[flags>>1]) & 0xFFFF).
+  **
+  ** The contents of this array are generated by parsing the CaseFolding.txt
+  ** file distributed as part of the "Unicode Character Database". See
+  ** http://www.unicode.org for details.
+  */
+  static const struct TableEntry {
+    unsigned short iCode;
+    unsigned char flags;
+    unsigned char nRange;
+  } aEntry[] = {
+    {65, 14, 26},          {181, 64, 1},          {192, 14, 23},
+    {216, 14, 7},          {256, 1, 48},          {306, 1, 6},
+    {313, 1, 16},          {330, 1, 46},          {376, 116, 1},
+    {377, 1, 6},           {383, 104, 1},         {385, 50, 1},
+    {386, 1, 4},           {390, 44, 1},          {391, 0, 1},
+    {393, 42, 2},          {395, 0, 1},           {398, 32, 1},
+    {399, 38, 1},          {400, 40, 1},          {401, 0, 1},
+    {403, 42, 1},          {404, 46, 1},          {406, 52, 1},
+    {407, 48, 1},          {408, 0, 1},           {412, 52, 1},
+    {413, 54, 1},          {415, 56, 1},          {416, 1, 6},
+    {422, 60, 1},          {423, 0, 1},           {425, 60, 1},
+    {428, 0, 1},           {430, 60, 1},          {431, 0, 1},
+    {433, 58, 2},          {435, 1, 4},           {439, 62, 1},
+    {440, 0, 1},           {444, 0, 1},           {452, 2, 1},
+    {453, 0, 1},           {455, 2, 1},           {456, 0, 1},
+    {458, 2, 1},           {459, 1, 18},          {478, 1, 18},
+    {497, 2, 1},           {498, 1, 4},           {502, 122, 1},
+    {503, 134, 1},         {504, 1, 40},          {544, 110, 1},
+    {546, 1, 18},          {570, 70, 1},          {571, 0, 1},
+    {573, 108, 1},         {574, 68, 1},          {577, 0, 1},
+    {579, 106, 1},         {580, 28, 1},          {581, 30, 1},
+    {582, 1, 10},          {837, 36, 1},          {880, 1, 4},
+    {886, 0, 1},           {902, 18, 1},          {904, 16, 3},
+    {908, 26, 1},          {910, 24, 2},          {913, 14, 17},
+    {931, 14, 9},          {962, 0, 1},           {975, 4, 1},
+    {976, 140, 1},         {977, 142, 1},         {981, 146, 1},
+    {982, 144, 1},         {984, 1, 24},          {1008, 136, 1},
+    {1009, 138, 1},        {1012, 130, 1},        {1013, 128, 1},
+    {1015, 0, 1},          {1017, 152, 1},        {1018, 0, 1},
+    {1021, 110, 3},        {1024, 34, 16},        {1040, 14, 32},
+    {1120, 1, 34},         {1162, 1, 54},         {1216, 6, 1},
+    {1217, 1, 14},         {1232, 1, 88},         {1329, 22, 38},
+    {4256, 66, 38},        {4295, 66, 1},         {4301, 66, 1},
+    {7680, 1, 150},        {7835, 132, 1},        {7838, 96, 1},
+    {7840, 1, 96},         {7944, 150, 8},        {7960, 150, 6},
+    {7976, 150, 8},        {7992, 150, 8},        {8008, 150, 6},
+    {8025, 151, 8},        {8040, 150, 8},        {8072, 150, 8},
+    {8088, 150, 8},        {8104, 150, 8},        {8120, 150, 2},
+    {8122, 126, 2},        {8124, 148, 1},        {8126, 100, 1},
+    {8136, 124, 4},        {8140, 148, 1},        {8152, 150, 2},
+    {8154, 120, 2},        {8168, 150, 2},        {8170, 118, 2},
+    {8172, 152, 1},        {8184, 112, 2},        {8186, 114, 2},
+    {8188, 148, 1},        {8486, 98, 1},         {8490, 92, 1},
+    {8491, 94, 1},         {8498, 12, 1},         {8544, 8, 16},
+    {8579, 0, 1},          {9398, 10, 26},        {11264, 22, 47},
+    {11360, 0, 1},         {11362, 88, 1},        {11363, 102, 1},
+    {11364, 90, 1},        {11367, 1, 6},         {11373, 84, 1},
+    {11374, 86, 1},        {11375, 80, 1},        {11376, 82, 1},
+    {11378, 0, 1},         {11381, 0, 1},         {11390, 78, 2},
+    {11392, 1, 100},       {11499, 1, 4},         {11506, 0, 1},
+    {42560, 1, 46},        {42624, 1, 24},        {42786, 1, 14},
+    {42802, 1, 62},        {42873, 1, 4},         {42877, 76, 1},
+    {42878, 1, 10},        {42891, 0, 1},         {42893, 74, 1},
+    {42896, 1, 4},         {42912, 1, 10},        {42922, 72, 1},
+    {65313, 14, 26},
+  };
+  static const unsigned short aiOff[] = {
+   1,     2,     8,     15,    16,    26,    28,    32,
+   37,    38,    40,    48,    63,    64,    69,    71,
+   79,    80,    116,   202,   203,   205,   206,   207,
+   209,   210,   211,   213,   214,   217,   218,   219,
+   775,   7264,  10792, 10795, 23228, 23256, 30204, 54721,
+   54753, 54754, 54756, 54787, 54793, 54809, 57153, 57274,
+   57921, 58019, 58363, 61722, 65268, 65341, 65373, 65406,
+   65408, 65410, 65415, 65424, 65436, 65439, 65450, 65462,
+   65472, 65476, 65478, 65480, 65482, 65488, 65506, 65511,
+   65514, 65521, 65527, 65528, 65529,
+  };
+
+  int ret = c;
+
+  assert( sizeof(unsigned short)==2 && sizeof(unsigned char)==1 );
+
+  if( c<128 ){
+    if( c>='A' && c<='Z' ) ret = c + ('a' - 'A');
+  }else if( c<65536 ){
+    const struct TableEntry *p;
+    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
+    int iLo = 0;
+    int iRes = -1;
+
+    assert( c>aEntry[0].iCode );
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      int cmp = (c - aEntry[iTest].iCode);
+      if( cmp>=0 ){
+        iRes = iTest;
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+
+    assert( iRes>=0 && c>=aEntry[iRes].iCode );
+    p = &aEntry[iRes];
+    if( c<(p->iCode + p->nRange) && 0==(0x01 & p->flags & (p->iCode ^ c)) ){
+      ret = (c + (aiOff[p->flags>>1])) & 0x0000FFFF;
+      assert( ret>0 );
+    }
+
+    if( eRemoveDiacritic ){
+      ret = remove_diacritic(ret, eRemoveDiacritic==2);
+    }
+  }
+
+  else if( c>=66560 && c<66600 ){
+    ret = c + 40;
+  }
+
+  return ret;
+}
+#endif /* defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4) */
+#endif /* !defined(SQLITE_DISABLE_FTS3_UNICODE) */
+
+/************** End of fts3_unicode2.c ***************************************/
+/************** Begin file json.c ********************************************/
+/*
+** 2015-08-12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** SQLite JSON functions.
+**
+** This file began as an extension in ext/misc/json1.c in 2015.  That
+** extension proved so useful that it has now been moved into the core.
+**
+** The original design stored all JSON as pure text, canonical RFC-8259.
+** Support for JSON-5 extensions was added with version 3.42.0 (2023-05-16).
+** All generated JSON text still conforms strictly to RFC-8259, but text
+** with JSON-5 extensions is accepted as input.
+**
+** Beginning with version 3.45.0 (circa 2024-01-01), these routines also
+** accept BLOB values that have JSON encoded using a binary representation
+** called "JSONB".  The name JSONB comes from PostgreSQL, however the on-disk
+** format SQLite JSONB is completely different and incompatible with
+** PostgreSQL JSONB.
+**
+** Decoding and interpreting JSONB is still O(N) where N is the size of
+** the input, the same as text JSON.  However, the constant of proportionality
+** for JSONB is much smaller due to faster parsing.  The size of each
+** element in JSONB is encoded in its header, so there is no need to search
+** for delimiters using persnickety syntax rules.  JSONB seems to be about
+** 3x faster than text JSON as a result.  JSONB is also tends to be slightly
+** smaller than text JSON, by 5% or 10%, but there are corner cases where
+** JSONB can be slightly larger.  So you are not far mistaken to say that
+** a JSONB blob is the same size as the equivalent RFC-8259 text.
+**
+**
+** THE JSONB ENCODING:
+**
+** Every JSON element is encoded in JSONB as a header and a payload.
+** The header is between 1 and 9 bytes in size.  The payload is zero
+** or more bytes.
+**
+** The lower 4 bits of the first byte of the header determines the
+** element type:
+**
+**    0:   NULL
+**    1:   TRUE
+**    2:   FALSE
+**    3:   INT        -- RFC-8259 integer literal
+**    4:   INT5       -- JSON5 integer literal
+**    5:   FLOAT      -- RFC-8259 floating point literal
+**    6:   FLOAT5     -- JSON5 floating point literal
+**    7:   TEXT       -- Text literal acceptable to both SQL and JSON
+**    8:   TEXTJ      -- Text containing RFC-8259 escapes
+**    9:   TEXT5      -- Text containing JSON5 and/or RFC-8259 escapes
+**   10:   TEXTRAW    -- Text containing unescaped syntax characters
+**   11:   ARRAY
+**   12:   OBJECT
+**
+** The other three possible values (13-15) are reserved for future
+** enhancements.
+**
+** The upper 4 bits of the first byte determine the size of the header
+** and sometimes also the size of the payload.  If X is the first byte
+** of the element and if X>>4 is between 0 and 11, then the payload
+** will be that many bytes in size and the header is exactly one byte
+** in size.  Other four values for X>>4 (12-15) indicate that the header
+** is more than one byte in size and that the payload size is determined
+** by the remainder of the header, interpreted as a unsigned big-endian
+** integer.
+**
+**   Value of X>>4         Size integer        Total header size
+**   -------------     --------------------    -----------------
+**        12           1 byte (0-255)                2
+**        13           2 byte (0-65535)              3
+**        14           4 byte (0-4294967295)         5
+**        15           8 byte (0-1.8e19)             9
+**
+** The payload size need not be expressed in its minimal form.  For example,
+** if the payload size is 10, the size can be expressed in any of 5 different
+** ways: (1) (X>>4)==10, (2) (X>>4)==12 following by on 0x0a byte,
+** (3) (X>>4)==13 followed by 0x00 and 0x0a, (4) (X>>4)==14 followed by
+** 0x00 0x00 0x00 0x0a, or (5) (X>>4)==15 followed by 7 bytes of 0x00 and
+** a single byte of 0x0a.  The shorter forms are preferred, of course, but
+** sometimes when generating JSONB, the payload size is not known in advance
+** and it is convenient to reserve sufficient header space to cover the
+** largest possible payload size and then come back later and patch up
+** the size when it becomes known, resulting in a non-minimal encoding.
+**
+** The value (X>>4)==15 is not actually used in the current implementation
+** (as SQLite is currently unable handle BLOBs larger than about 2GB)
+** but is included in the design to allow for future enhancements.
+**
+** The payload follows the header.  NULL, TRUE, and FALSE have no payload and
+** their payload size must always be zero.  The payload for INT, INT5,
+** FLOAT, FLOAT5, TEXT, TEXTJ, TEXT5, and TEXTROW is text.  Note that the
+** "..." or '...' delimiters are omitted from the various text encodings.
+** The payload for ARRAY and OBJECT is a list of additional elements that
+** are the content for the array or object.  The payload for an OBJECT
+** must be an even number of elements.  The first element of each pair is
+** the label and must be of type TEXT, TEXTJ, TEXT5, or TEXTRAW.
+**
+** A valid JSONB blob consists of a single element, as described above.
+** Usually this will be an ARRAY or OBJECT element which has many more
+** elements as its content.  But the overall blob is just a single element.
+**
+** Input validation for JSONB blobs simply checks that the element type
+** code is between 0 and 12 and that the total size of the element
+** (header plus payload) is the same as the size of the BLOB.  If those
+** checks are true, the BLOB is assumed to be JSONB and processing continues.
+** Errors are only raised if some other miscoding is discovered during
+** processing.
+**
+** Additional information can be found in the doc/jsonb.md file of the
+** canonical SQLite source tree.
+*/
+#ifndef SQLITE_OMIT_JSON
+/* #include "sqliteInt.h" */
+
+/* JSONB element types
+*/
+#define JSONB_NULL     0   /* "null" */
+#define JSONB_TRUE     1   /* "true" */
+#define JSONB_FALSE    2   /* "false" */
+#define JSONB_INT      3   /* integer acceptable to JSON and SQL */
+#define JSONB_INT5     4   /* integer in 0x000 notation */
+#define JSONB_FLOAT    5   /* float acceptable to JSON and SQL */
+#define JSONB_FLOAT5   6   /* float with JSON5 extensions */
+#define JSONB_TEXT     7   /* Text compatible with both JSON and SQL */
+#define JSONB_TEXTJ    8   /* Text with JSON escapes */
+#define JSONB_TEXT5    9   /* Text with JSON-5 escape */
+#define JSONB_TEXTRAW 10   /* SQL text that needs escaping for JSON */
+#define JSONB_ARRAY   11   /* An array */
+#define JSONB_OBJECT  12   /* An object */
+
+/* Human-readable names for the JSONB values.  The index for each
+** string must correspond to the JSONB_* integer above.
+*/
+static const char * const jsonbType[] = {
+  "null", "true", "false", "integer", "integer",
+  "real", "real", "text",  "text",    "text",
+  "text", "array", "object", "", "", "", ""
+};
+
+/*
+** Growing our own isspace() routine this way is twice as fast as
+** the library isspace() function, resulting in a 7% overall performance
+** increase for the text-JSON parser.  (Ubuntu14.10 gcc 4.8.4 x64 with -Os).
+*/
+static const char jsonIsSpace[] = {
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 1, 1, 0, 0, 1, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  1, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+};
+#define jsonIsspace(x) (jsonIsSpace[(unsigned char)x])
+
+/*
+** The set of all space characters recognized by jsonIsspace().
+** Useful as the second argument to strspn().
+*/
+static const char jsonSpaces[] = "\011\012\015\040";
+
+/*
+** Characters that are special to JSON.  Control characters,
+** '"' and '\\' and '\''.  Actually, '\'' is not special to
+** canonical JSON, but it is special in JSON-5, so we include
+** it in the set of special characters.
+*/
+static const char jsonIsOk[256] = {
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  1, 1, 0, 1, 1, 1, 1, 0,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 0, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1
+};
+
+/* Objects */
+typedef struct JsonCache JsonCache;
+typedef struct JsonString JsonString;
+typedef struct JsonParse JsonParse;
+
+/*
+** Magic number used for the JSON parse cache in sqlite3_get_auxdata()
+*/
+#define JSON_CACHE_ID    (-429938)  /* Cache entry */
+#define JSON_CACHE_SIZE  4          /* Max number of cache entries */
+
+/*
+** jsonUnescapeOneChar() returns this invalid code point if it encounters
+** a syntax error.
+*/
+#define JSON_INVALID_CHAR 0x99999
+
+/* A cache mapping JSON text into JSONB blobs.
+**
+** Each cache entry is a JsonParse object with the following restrictions:
+**
+**    *   The bReadOnly flag must be set
+**
+**    *   The aBlob[] array must be owned by the JsonParse object.  In other
+**        words, nBlobAlloc must be non-zero.
+**
+**    *   eEdit and delta must be zero.
+**
+**    *   zJson must be an RCStr.  In other words bJsonIsRCStr must be true.
+*/
+struct JsonCache {
+  sqlite3 *db;                    /* Database connection */
+  int nUsed;                      /* Number of active entries in the cache */
+  JsonParse *a[JSON_CACHE_SIZE];  /* One line for each cache entry */
+};
+
+/* An instance of this object represents a JSON string
+** under construction.  Really, this is a generic string accumulator
+** that can be and is used to create strings other than JSON.
+**
+** If the generated string is longer than will fit into the zSpace[] buffer,
+** then it will be an RCStr string.  This aids with caching of large
+** JSON strings.
+*/
+struct JsonString {
+  sqlite3_context *pCtx;   /* Function context - put error messages here */
+  char *zBuf;              /* Append JSON content here */
+  u64 nAlloc;              /* Bytes of storage available in zBuf[] */
+  u64 nUsed;               /* Bytes of zBuf[] currently used */
+  u8 bStatic;              /* True if zBuf is static space */
+  u8 eErr;                 /* True if an error has been encountered */
+  char zSpace[100];        /* Initial static space */
+};
+
+/* Allowed values for JsonString.eErr */
+#define JSTRING_OOM         0x01   /* Out of memory */
+#define JSTRING_MALFORMED   0x02   /* Malformed JSONB */
+#define JSTRING_ERR         0x04   /* Error already sent to sqlite3_result */
+
+/* The "subtype" set for text JSON values passed through using
+** sqlite3_result_subtype() and sqlite3_value_subtype().
+*/
+#define JSON_SUBTYPE  74    /* Ascii for "J" */
+
+/*
+** Bit values for the flags passed into various SQL function implementations
+** via the sqlite3_user_data() value.
+*/
+#define JSON_JSON      0x01        /* Result is always JSON */
+#define JSON_SQL       0x02        /* Result is always SQL */
+#define JSON_ABPATH    0x03        /* Allow abbreviated JSON path specs */
+#define JSON_ISSET     0x04        /* json_set(), not json_insert() */
+#define JSON_BLOB      0x08        /* Use the BLOB output format */
+
+
+/* A parsed JSON value.  Lifecycle:
+**
+**   1.  JSON comes in and is parsed into a JSONB value in aBlob.  The
+**       original text is stored in zJson.  This step is skipped if the
+**       input is JSONB instead of text JSON.
+**
+**   2.  The aBlob[] array is searched using the JSON path notation, if needed.
+**
+**   3.  Zero or more changes are made to aBlob[] (via json_remove() or
+**       json_replace() or json_patch() or similar).
+**
+**   4.  New JSON text is generated from the aBlob[] for output.  This step
+**       is skipped if the function is one of the jsonb_* functions that
+**       returns JSONB instead of text JSON.
+*/
+struct JsonParse {
+  u8 *aBlob;         /* JSONB representation of JSON value */
+  u32 nBlob;         /* Bytes of aBlob[] actually used */
+  u32 nBlobAlloc;    /* Bytes allocated to aBlob[].  0 if aBlob is external */
+  char *zJson;       /* Json text used for parsing */
+  sqlite3 *db;       /* The database connection to which this object belongs */
+  int nJson;         /* Length of the zJson string in bytes */
+  u32 nJPRef;        /* Number of references to this object */
+  u32 iErr;          /* Error location in zJson[] */
+  u16 iDepth;        /* Nesting depth */
+  u8 nErr;           /* Number of errors seen */
+  u8 oom;            /* Set to true if out of memory */
+  u8 bJsonIsRCStr;   /* True if zJson is an RCStr */
+  u8 hasNonstd;      /* True if input uses non-standard features like JSON5 */
+  u8 bReadOnly;      /* Do not modify. */
+  /* Search and edit information.  See jsonLookupStep() */
+  u8 eEdit;          /* Edit operation to apply */
+  int delta;         /* Size change due to the edit */
+  u32 nIns;          /* Number of bytes to insert */
+  u32 iLabel;        /* Location of label if search landed on an object value */
+  u8 *aIns;          /* Content to be inserted */
+};
+
+/* Allowed values for JsonParse.eEdit */
+#define JEDIT_DEL   1   /* Delete if exists */
+#define JEDIT_REPL  2   /* Overwrite if exists */
+#define JEDIT_INS   3   /* Insert if not exists */
+#define JEDIT_SET   4   /* Insert or overwrite */
+
+/*
+** Maximum nesting depth of JSON for this implementation.
+**
+** This limit is needed to avoid a stack overflow in the recursive
+** descent parser.  A depth of 1000 is far deeper than any sane JSON
+** should go.  Historical note: This limit was 2000 prior to version 3.42.0
+*/
+#ifndef SQLITE_JSON_MAX_DEPTH
+# define JSON_MAX_DEPTH  1000
+#else
+# define JSON_MAX_DEPTH SQLITE_JSON_MAX_DEPTH
+#endif
+
+/*
+** Allowed values for the flgs argument to jsonParseFuncArg();
+*/
+#define JSON_EDITABLE  0x01   /* Generate a writable JsonParse object */
+#define JSON_KEEPERROR 0x02   /* Return non-NULL even if there is an error */
+
+/**************************************************************************
+** Forward references
+**************************************************************************/
+static void jsonReturnStringAsBlob(JsonString*);
+static int jsonFuncArgMightBeBinary(sqlite3_value *pJson);
+static u32 jsonTranslateBlobToText(const JsonParse*,u32,JsonString*);
+static void jsonReturnParse(sqlite3_context*,JsonParse*);
+static JsonParse *jsonParseFuncArg(sqlite3_context*,sqlite3_value*,u32);
+static void jsonParseFree(JsonParse*);
+static u32 jsonbPayloadSize(const JsonParse*, u32, u32*);
+static u32 jsonUnescapeOneChar(const char*, u32, u32*);
+
+/**************************************************************************
+** Utility routines for dealing with JsonCache objects
+**************************************************************************/
+
+/*
+** Free a JsonCache object.
+*/
+static void jsonCacheDelete(JsonCache *p){
+  int i;
+  for(i=0; i<p->nUsed; i++){
+    jsonParseFree(p->a[i]);
+  }
+  sqlite3DbFree(p->db, p);
+}
+static void jsonCacheDeleteGeneric(void *p){
+  jsonCacheDelete((JsonCache*)p);
+}
+
+/*
+** Insert a new entry into the cache.  If the cache is full, expel
+** the least recently used entry.  Return SQLITE_OK on success or a
+** result code otherwise.
+**
+** Cache entries are stored in age order, oldest first.
+*/
+static int jsonCacheInsert(
+  sqlite3_context *ctx,   /* The SQL statement context holding the cache */
+  JsonParse *pParse       /* The parse object to be added to the cache */
+){
+  JsonCache *p;
+
+  assert( pParse->zJson!=0 );
+  assert( pParse->bJsonIsRCStr );
+  assert( pParse->delta==0 );
+  p = sqlite3_get_auxdata(ctx, JSON_CACHE_ID);
+  if( p==0 ){
+    sqlite3 *db = sqlite3_context_db_handle(ctx);
+    p = sqlite3DbMallocZero(db, sizeof(*p));
+    if( p==0 ) return SQLITE_NOMEM;
+    p->db = db;
+    sqlite3_set_auxdata(ctx, JSON_CACHE_ID, p, jsonCacheDeleteGeneric);
+    p = sqlite3_get_auxdata(ctx, JSON_CACHE_ID);
+    if( p==0 ) return SQLITE_NOMEM;
+  }
+  if( p->nUsed >= JSON_CACHE_SIZE ){
+    jsonParseFree(p->a[0]);
+    memmove(p->a, &p->a[1], (JSON_CACHE_SIZE-1)*sizeof(p->a[0]));
+    p->nUsed = JSON_CACHE_SIZE-1;
+  }
+  assert( pParse->nBlobAlloc>0 );
+  pParse->eEdit = 0;
+  pParse->nJPRef++;
+  pParse->bReadOnly = 1;
+  p->a[p->nUsed] = pParse;
+  p->nUsed++;
+  return SQLITE_OK;
+}
+
+/*
+** Search for a cached translation the json text supplied by pArg.  Return
+** the JsonParse object if found.  Return NULL if not found.
+**
+** When a match if found, the matching entry is moved to become the
+** most-recently used entry if it isn't so already.
+**
+** The JsonParse object returned still belongs to the Cache and might
+** be deleted at any moment.  If the caller whants the JsonParse to
+** linger, it needs to increment the nPJRef reference counter.
+*/
+static JsonParse *jsonCacheSearch(
+  sqlite3_context *ctx,    /* The SQL statement context holding the cache */
+  sqlite3_value *pArg      /* Function argument containing SQL text */
+){
+  JsonCache *p;
+  int i;
+  const char *zJson;
+  int nJson;
+
+  if( sqlite3_value_type(pArg)!=SQLITE_TEXT ){
+    return 0;
+  }
+  zJson = (const char*)sqlite3_value_text(pArg);
+  if( zJson==0 ) return 0;
+  nJson = sqlite3_value_bytes(pArg);
+
+  p = sqlite3_get_auxdata(ctx, JSON_CACHE_ID);
+  if( p==0 ){
+    return 0;
+  }
+  for(i=0; i<p->nUsed; i++){
+    if( p->a[i]->zJson==zJson ) break;
+  }
+  if( i>=p->nUsed ){
+    for(i=0; i<p->nUsed; i++){
+      if( p->a[i]->nJson!=nJson ) continue;
+      if( memcmp(p->a[i]->zJson, zJson, nJson)==0 ) break;
+    }
+  }
+  if( i<p->nUsed ){
+    if( i<p->nUsed-1 ){
+      /* Make the matching entry the most recently used entry */
+      JsonParse *tmp = p->a[i];
+      memmove(&p->a[i], &p->a[i+1], (p->nUsed-i-1)*sizeof(tmp));
+      p->a[p->nUsed-1] = tmp;
+      i = p->nUsed - 1;
+    }
+    assert( p->a[i]->delta==0 );
+    return p->a[i];
+  }else{
+    return 0;
+  }
+}
+
+/**************************************************************************
+** Utility routines for dealing with JsonString objects
+**************************************************************************/
+
+/* Turn uninitialized bulk memory into a valid JsonString object
+** holding a zero-length string.
+*/
+static void jsonStringZero(JsonString *p){
+  p->zBuf = p->zSpace;
+  p->nAlloc = sizeof(p->zSpace);
+  p->nUsed = 0;
+  p->bStatic = 1;
+}
+
+/* Initialize the JsonString object
+*/
+static void jsonStringInit(JsonString *p, sqlite3_context *pCtx){
+  p->pCtx = pCtx;
+  p->eErr = 0;
+  jsonStringZero(p);
+}
+
+/* Free all allocated memory and reset the JsonString object back to its
+** initial state.
+*/
+static void jsonStringReset(JsonString *p){
+  if( !p->bStatic ) sqlite3RCStrUnref(p->zBuf);
+  jsonStringZero(p);
+}
+
+/* Report an out-of-memory (OOM) condition
+*/
+static void jsonStringOom(JsonString *p){
+  p->eErr |= JSTRING_OOM;
+  if( p->pCtx ) sqlite3_result_error_nomem(p->pCtx);
+  jsonStringReset(p);
+}
+
+/* Enlarge pJson->zBuf so that it can hold at least N more bytes.
+** Return zero on success.  Return non-zero on an OOM error
+*/
+static int jsonStringGrow(JsonString *p, u32 N){
+  u64 nTotal = N<p->nAlloc ? p->nAlloc*2 : p->nAlloc+N+10;
+  char *zNew;
+  if( p->bStatic ){
+    if( p->eErr ) return 1;
+    zNew = sqlite3RCStrNew(nTotal);
+    if( zNew==0 ){
+      jsonStringOom(p);
+      return SQLITE_NOMEM;
+    }
+    memcpy(zNew, p->zBuf, (size_t)p->nUsed);
+    p->zBuf = zNew;
+    p->bStatic = 0;
+  }else{
+    p->zBuf = sqlite3RCStrResize(p->zBuf, nTotal);
+    if( p->zBuf==0 ){
+      p->eErr |= JSTRING_OOM;
+      jsonStringZero(p);
+      return SQLITE_NOMEM;
+    }
+  }
+  p->nAlloc = nTotal;
+  return SQLITE_OK;
+}
+
+/* Append N bytes from zIn onto the end of the JsonString string.
+*/
+static SQLITE_NOINLINE void jsonStringExpandAndAppend(
+  JsonString *p,
+  const char *zIn,
+  u32 N
+){
+  assert( N>0 );
+  if( jsonStringGrow(p,N) ) return;
+  memcpy(p->zBuf+p->nUsed, zIn, N);
+  p->nUsed += N;
+}
+static void jsonAppendRaw(JsonString *p, const char *zIn, u32 N){
+  if( N==0 ) return;
+  if( N+p->nUsed >= p->nAlloc ){
+    jsonStringExpandAndAppend(p,zIn,N);
+  }else{
+    memcpy(p->zBuf+p->nUsed, zIn, N);
+    p->nUsed += N;
+  }
+}
+static void jsonAppendRawNZ(JsonString *p, const char *zIn, u32 N){
+  assert( N>0 );
+  if( N+p->nUsed >= p->nAlloc ){
+    jsonStringExpandAndAppend(p,zIn,N);
+  }else{
+    memcpy(p->zBuf+p->nUsed, zIn, N);
+    p->nUsed += N;
+  }
+}
+
+/* Append formatted text (not to exceed N bytes) to the JsonString.
+*/
+static void jsonPrintf(int N, JsonString *p, const char *zFormat, ...){
+  va_list ap;
+  if( (p->nUsed + N >= p->nAlloc) && jsonStringGrow(p, N) ) return;
+  va_start(ap, zFormat);
+  sqlite3_vsnprintf(N, p->zBuf+p->nUsed, zFormat, ap);
+  va_end(ap);
+  p->nUsed += (int)strlen(p->zBuf+p->nUsed);
+}
+
+/* Append a single character
+*/
+static SQLITE_NOINLINE void jsonAppendCharExpand(JsonString *p, char c){
+  if( jsonStringGrow(p,1) ) return;
+  p->zBuf[p->nUsed++] = c;
+}
+static void jsonAppendChar(JsonString *p, char c){
+  if( p->nUsed>=p->nAlloc ){
+    jsonAppendCharExpand(p,c);
+  }else{
+    p->zBuf[p->nUsed++] = c;
+  }
+}
+
+/* Remove a single character from the end of the string
+*/
+static void jsonStringTrimOneChar(JsonString *p){
+  if( p->eErr==0 ){
+    assert( p->nUsed>0 );
+    p->nUsed--;
+  }
+}
+
+
+/* Make sure there is a zero terminator on p->zBuf[]
+**
+** Return true on success.  Return false if an OOM prevents this
+** from happening.
+*/
+static int jsonStringTerminate(JsonString *p){
+  jsonAppendChar(p, 0);
+  jsonStringTrimOneChar(p);
+  return p->eErr==0;
+}
+
+/* Append a comma separator to the output buffer, if the previous
+** character is not '[' or '{'.
+*/
+static void jsonAppendSeparator(JsonString *p){
+  char c;
+  if( p->nUsed==0 ) return;
+  c = p->zBuf[p->nUsed-1];
+  if( c=='[' || c=='{' ) return;
+  jsonAppendChar(p, ',');
+}
+
+/* c is a control character.  Append the canonical JSON representation
+** of that control character to p.
+**
+** This routine assumes that the output buffer has already been enlarged
+** sufficiently to hold the worst-case encoding plus a nul terminator.
+*/
+static void jsonAppendControlChar(JsonString *p, u8 c){
+  static const char aSpecial[] = {
+     0, 0, 0, 0, 0, 0, 0, 0, 'b', 't', 'n', 0, 'f', 'r', 0, 0,
+     0, 0, 0, 0, 0, 0, 0, 0,   0,   0,   0, 0,   0,   0, 0, 0
+  };
+  assert( sizeof(aSpecial)==32 );
+  assert( aSpecial['\b']=='b' );
+  assert( aSpecial['\f']=='f' );
+  assert( aSpecial['\n']=='n' );
+  assert( aSpecial['\r']=='r' );
+  assert( aSpecial['\t']=='t' );
+  assert( c>=0 && c<sizeof(aSpecial) );
+  assert( p->nUsed+7 <= p->nAlloc );
+  if( aSpecial[c] ){
+    p->zBuf[p->nUsed] = '\\';
+    p->zBuf[p->nUsed+1] = aSpecial[c];
+    p->nUsed += 2;
+  }else{
+    p->zBuf[p->nUsed] = '\\';
+    p->zBuf[p->nUsed+1] = 'u';
+    p->zBuf[p->nUsed+2] = '0';
+    p->zBuf[p->nUsed+3] = '0';
+    p->zBuf[p->nUsed+4] = "0123456789abcdef"[c>>4];
+    p->zBuf[p->nUsed+5] = "0123456789abcdef"[c&0xf];
+    p->nUsed += 6;
+  }
+}
+
+/* Append the N-byte string in zIn to the end of the JsonString string
+** under construction.  Enclose the string in double-quotes ("...") and
+** escape any double-quotes or backslash characters contained within the
+** string.
+**
+** This routine is a high-runner.  There is a measurable performance
+** increase associated with unwinding the jsonIsOk[] loop.
+*/
+static void jsonAppendString(JsonString *p, const char *zIn, u32 N){
+  u32 k;
+  u8 c;
+  const u8 *z = (const u8*)zIn;
+  if( z==0 ) return;
+  if( (N+p->nUsed+2 >= p->nAlloc) && jsonStringGrow(p,N+2)!=0 ) return;
+  p->zBuf[p->nUsed++] = '"';
+  while( 1 /*exit-by-break*/ ){
+    k = 0;
+    /* The following while() is the 4-way unwound equivalent of
+    **
+    **     while( k<N && jsonIsOk[z[k]] ){ k++; }
+    */
+    while( 1 /* Exit by break */ ){
+      if( k+3>=N ){
+        while( k<N && jsonIsOk[z[k]] ){ k++; }
+        break;
+      }
+      if( !jsonIsOk[z[k]] ){
+        break;
+      }
+      if( !jsonIsOk[z[k+1]] ){
+        k += 1;
+        break;
+      }
+      if( !jsonIsOk[z[k+2]] ){
+        k += 2;
+        break;
+      }
+      if( !jsonIsOk[z[k+3]] ){
+        k += 3;
+        break;
+      }else{
+        k += 4;
+      }
+    }
+    if( k>=N ){
+      if( k>0 ){
+        memcpy(&p->zBuf[p->nUsed], z, k);
+        p->nUsed += k;
+      }
+      break;
+    }
+    if( k>0 ){
+      memcpy(&p->zBuf[p->nUsed], z, k);
+      p->nUsed += k;
+      z += k;
+      N -= k;
+    }
+    c = z[0];
+    if( c=='"' || c=='\\' ){
+      if( (p->nUsed+N+3 > p->nAlloc) && jsonStringGrow(p,N+3)!=0 ) return;
+      p->zBuf[p->nUsed++] = '\\';
+      p->zBuf[p->nUsed++] = c;
+    }else if( c=='\'' ){
+      p->zBuf[p->nUsed++] = c;
+    }else{
+      if( (p->nUsed+N+7 > p->nAlloc) && jsonStringGrow(p,N+7)!=0 ) return;
+      jsonAppendControlChar(p, c);
+    }
+    z++;
+    N--;
+  }
+  p->zBuf[p->nUsed++] = '"';
+  assert( p->nUsed<p->nAlloc );
+}
+
+/*
+** Append an sqlite3_value (such as a function parameter) to the JSON
+** string under construction in p.
+*/
+static void jsonAppendSqlValue(
+  JsonString *p,                 /* Append to this JSON string */
+  sqlite3_value *pValue          /* Value to append */
+){
+  switch( sqlite3_value_type(pValue) ){
+    case SQLITE_NULL: {
+      jsonAppendRawNZ(p, "null", 4);
+      break;
+    }
+    case SQLITE_FLOAT: {
+      jsonPrintf(100, p, "%!0.15g", sqlite3_value_double(pValue));
+      break;
+    }
+    case SQLITE_INTEGER: {
+      const char *z = (const char*)sqlite3_value_text(pValue);
+      u32 n = (u32)sqlite3_value_bytes(pValue);
+      jsonAppendRaw(p, z, n);
+      break;
+    }
+    case SQLITE_TEXT: {
+      const char *z = (const char*)sqlite3_value_text(pValue);
+      u32 n = (u32)sqlite3_value_bytes(pValue);
+      if( sqlite3_value_subtype(pValue)==JSON_SUBTYPE ){
+        jsonAppendRaw(p, z, n);
+      }else{
+        jsonAppendString(p, z, n);
+      }
+      break;
+    }
+    default: {
+      if( jsonFuncArgMightBeBinary(pValue) ){
+        JsonParse px;
+        memset(&px, 0, sizeof(px));
+        px.aBlob = (u8*)sqlite3_value_blob(pValue);
+        px.nBlob = sqlite3_value_bytes(pValue);
+        jsonTranslateBlobToText(&px, 0, p);
+      }else if( p->eErr==0 ){
+        sqlite3_result_error(p->pCtx, "JSON cannot hold BLOB values", -1);
+        p->eErr = JSTRING_ERR;
+        jsonStringReset(p);
+      }
+      break;
+    }
+  }
+}
+
+/* Make the text in p (which is probably a generated JSON text string)
+** the result of the SQL function.
+**
+** The JsonString is reset.
+**
+** If pParse and ctx are both non-NULL, then the SQL string in p is
+** loaded into the zJson field of the pParse object as a RCStr and the
+** pParse is added to the cache.
+*/
+static void jsonReturnString(
+  JsonString *p,            /* String to return */
+  JsonParse *pParse,        /* JSONB source or NULL */
+  sqlite3_context *ctx      /* Where to cache */
+){
+  assert( (pParse!=0)==(ctx!=0) );
+  assert( ctx==0 || ctx==p->pCtx );
+  if( p->eErr==0 ){
+    int flags = SQLITE_PTR_TO_INT(sqlite3_user_data(p->pCtx));
+    if( flags & JSON_BLOB ){
+      jsonReturnStringAsBlob(p);
+    }else if( p->bStatic ){
+      sqlite3_result_text64(p->pCtx, p->zBuf, p->nUsed,
+                            SQLITE_TRANSIENT, SQLITE_UTF8);
+    }else if( jsonStringTerminate(p) ){
+      if( pParse && pParse->bJsonIsRCStr==0 && pParse->nBlobAlloc>0 ){
+        int rc;
+        pParse->zJson = sqlite3RCStrRef(p->zBuf);
+        pParse->nJson = p->nUsed;
+        pParse->bJsonIsRCStr = 1;
+        rc = jsonCacheInsert(ctx, pParse);
+        if( rc==SQLITE_NOMEM ){
+          sqlite3_result_error_nomem(ctx);
+          jsonStringReset(p);
+          return;
+        }
+      }
+      sqlite3_result_text64(p->pCtx, sqlite3RCStrRef(p->zBuf), p->nUsed,
+                            sqlite3RCStrUnref,
+                            SQLITE_UTF8);
+    }else{
+      sqlite3_result_error_nomem(p->pCtx);
+    }
+  }else if( p->eErr & JSTRING_OOM ){
+    sqlite3_result_error_nomem(p->pCtx);
+  }else if( p->eErr & JSTRING_MALFORMED ){
+    sqlite3_result_error(p->pCtx, "malformed JSON", -1);
+  }
+  jsonStringReset(p);
+}
+
+/**************************************************************************
+** Utility routines for dealing with JsonParse objects
+**************************************************************************/
+
+/*
+** Reclaim all memory allocated by a JsonParse object.  But do not
+** delete the JsonParse object itself.
+*/
+static void jsonParseReset(JsonParse *pParse){
+  assert( pParse->nJPRef<=1 );
+  if( pParse->bJsonIsRCStr ){
+    sqlite3RCStrUnref(pParse->zJson);
+    pParse->zJson = 0;
+    pParse->nJson = 0;
+    pParse->bJsonIsRCStr = 0;
+  }
+  if( pParse->nBlobAlloc ){
+    sqlite3DbFree(pParse->db, pParse->aBlob);
+    pParse->aBlob = 0;
+    pParse->nBlob = 0;
+    pParse->nBlobAlloc = 0;
+  }
+}
+
+/*
+** Decrement the reference count on the JsonParse object.  When the
+** count reaches zero, free the object.
+*/
+static void jsonParseFree(JsonParse *pParse){
+  if( pParse ){
+    if( pParse->nJPRef>1 ){
+      pParse->nJPRef--;
+    }else{
+      jsonParseReset(pParse);
+      sqlite3DbFree(pParse->db, pParse);
+    }
+  }
+}
+
+/**************************************************************************
+** Utility routines for the JSON text parser
+**************************************************************************/
+
+/*
+** Translate a single byte of Hex into an integer.
+** This routine only gives a correct answer if h really is a valid hexadecimal
+** character:  0..9a..fA..F.  But unlike sqlite3HexToInt(), it does not
+** assert() if the digit is not hex.
+*/
+static u8 jsonHexToInt(int h){
+#ifdef SQLITE_ASCII
+  h += 9*(1&(h>>6));
+#endif
+#ifdef SQLITE_EBCDIC
+  h += 9*(1&~(h>>4));
+#endif
+  return (u8)(h & 0xf);
+}
+
+/*
+** Convert a 4-byte hex string into an integer
+*/
+static u32 jsonHexToInt4(const char *z){
+  u32 v;
+  v = (jsonHexToInt(z[0])<<12)
+    + (jsonHexToInt(z[1])<<8)
+    + (jsonHexToInt(z[2])<<4)
+    + jsonHexToInt(z[3]);
+  return v;
+}
+
+/*
+** Return true if z[] begins with 2 (or more) hexadecimal digits
+*/
+static int jsonIs2Hex(const char *z){
+  return sqlite3Isxdigit(z[0]) && sqlite3Isxdigit(z[1]);
+}
+
+/*
+** Return true if z[] begins with 4 (or more) hexadecimal digits
+*/
+static int jsonIs4Hex(const char *z){
+  return jsonIs2Hex(z) && jsonIs2Hex(&z[2]);
+}
+
+/*
+** Return the number of bytes of JSON5 whitespace at the beginning of
+** the input string z[].
+**
+** JSON5 whitespace consists of any of the following characters:
+**
+**    Unicode  UTF-8         Name
+**    U+0009   09            horizontal tab
+**    U+000a   0a            line feed
+**    U+000b   0b            vertical tab
+**    U+000c   0c            form feed
+**    U+000d   0d            carriage return
+**    U+0020   20            space
+**    U+00a0   c2 a0         non-breaking space
+**    U+1680   e1 9a 80      ogham space mark
+**    U+2000   e2 80 80      en quad
+**    U+2001   e2 80 81      em quad
+**    U+2002   e2 80 82      en space
+**    U+2003   e2 80 83      em space
+**    U+2004   e2 80 84      three-per-em space
+**    U+2005   e2 80 85      four-per-em space
+**    U+2006   e2 80 86      six-per-em space
+**    U+2007   e2 80 87      figure space
+**    U+2008   e2 80 88      punctuation space
+**    U+2009   e2 80 89      thin space
+**    U+200a   e2 80 8a      hair space
+**    U+2028   e2 80 a8      line separator
+**    U+2029   e2 80 a9      paragraph separator
+**    U+202f   e2 80 af      narrow no-break space (NNBSP)
+**    U+205f   e2 81 9f      medium mathematical space (MMSP)
+**    U+3000   e3 80 80      ideographical space
+**    U+FEFF   ef bb bf      byte order mark
+**
+** In addition, comments between '/', '*' and '*', '/' and
+** from '/', '/' to end-of-line are also considered to be whitespace.
+*/
+static int json5Whitespace(const char *zIn){
+  int n = 0;
+  const u8 *z = (u8*)zIn;
+  while( 1 /*exit by "goto whitespace_done"*/ ){
+    switch( z[n] ){
+      case 0x09:
+      case 0x0a:
+      case 0x0b:
+      case 0x0c:
+      case 0x0d:
+      case 0x20: {
+        n++;
+        break;
+      }
+      case '/': {
+        if( z[n+1]=='*' && z[n+2]!=0 ){
+          int j;
+          for(j=n+3; z[j]!='/' || z[j-1]!='*'; j++){
+            if( z[j]==0 ) goto whitespace_done;
+          }
+          n = j+1;
+          break;
+        }else if( z[n+1]=='/' ){
+          int j;
+          char c;
+          for(j=n+2; (c = z[j])!=0; j++){
+            if( c=='\n' || c=='\r' ) break;
+            if( 0xe2==(u8)c && 0x80==(u8)z[j+1]
+             && (0xa8==(u8)z[j+2] || 0xa9==(u8)z[j+2])
+            ){
+              j += 2;
+              break;
+            }
+          }
+          n = j;
+          if( z[n] ) n++;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xc2: {
+        if( z[n+1]==0xa0 ){
+          n += 2;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xe1: {
+        if( z[n+1]==0x9a && z[n+2]==0x80 ){
+          n += 3;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xe2: {
+        if( z[n+1]==0x80 ){
+          u8 c = z[n+2];
+          if( c<0x80 ) goto whitespace_done;
+          if( c<=0x8a || c==0xa8 || c==0xa9 || c==0xaf ){
+            n += 3;
+            break;
+          }
+        }else if( z[n+1]==0x81 && z[n+2]==0x9f ){
+          n += 3;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xe3: {
+        if( z[n+1]==0x80 && z[n+2]==0x80 ){
+          n += 3;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xef: {
+        if( z[n+1]==0xbb && z[n+2]==0xbf ){
+          n += 3;
+          break;
+        }
+        goto whitespace_done;
+      }
+      default: {
+        goto whitespace_done;
+      }
+    }
+  }
+  whitespace_done:
+  return n;
+}
+
+/*
+** Extra floating-point literals to allow in JSON.
+*/
+static const struct NanInfName {
+  char c1;
+  char c2;
+  char n;
+  char eType;
+  char nRepl;
+  char *zMatch;
+  char *zRepl;
+} aNanInfName[] = {
+  { 'i', 'I', 3, JSONB_FLOAT, 7, "inf", "9.0e999" },
+  { 'i', 'I', 8, JSONB_FLOAT, 7, "infinity", "9.0e999" },
+  { 'n', 'N', 3, JSONB_NULL, 4, "NaN", "null" },
+  { 'q', 'Q', 4, JSONB_NULL, 4, "QNaN", "null" },
+  { 's', 'S', 4, JSONB_NULL, 4, "SNaN", "null" },
+};
+
+
+/*
+** Report the wrong number of arguments for json_insert(), json_replace()
+** or json_set().
+*/
+static void jsonWrongNumArgs(
+  sqlite3_context *pCtx,
+  const char *zFuncName
+){
+  char *zMsg = sqlite3_mprintf("json_%s() needs an odd number of arguments",
+                               zFuncName);
+  sqlite3_result_error(pCtx, zMsg, -1);
+  sqlite3_free(zMsg);
+}
+
+/****************************************************************************
+** Utility routines for dealing with the binary BLOB representation of JSON
+****************************************************************************/
+
+/*
+** Expand pParse->aBlob so that it holds at least N bytes.
+**
+** Return the number of errors.
+*/
+static int jsonBlobExpand(JsonParse *pParse, u32 N){
+  u8 *aNew;
+  u32 t;
+  assert( N>pParse->nBlobAlloc );
+  if( pParse->nBlobAlloc==0 ){
+    t = 100;
+  }else{
+    t = pParse->nBlobAlloc*2;
+  }
+  if( t<N ) t = N+100;
+  aNew = sqlite3DbRealloc(pParse->db, pParse->aBlob, t);
+  if( aNew==0 ){ pParse->oom = 1; return 1; }
+  pParse->aBlob = aNew;
+  pParse->nBlobAlloc = t;
+  return 0;
+}
+
+/*
+** If pParse->aBlob is not previously editable (because it is taken
+** from sqlite3_value_blob(), as indicated by the fact that
+** pParse->nBlobAlloc==0 and pParse->nBlob>0) then make it editable
+** by making a copy into space obtained from malloc.
+**
+** Return true on success.  Return false on OOM.
+*/
+static int jsonBlobMakeEditable(JsonParse *pParse, u32 nExtra){
+  u8 *aOld;
+  u32 nSize;
+  assert( !pParse->bReadOnly );
+  if( pParse->oom ) return 0;
+  if( pParse->nBlobAlloc>0 ) return 1;
+  aOld = pParse->aBlob;
+  nSize = pParse->nBlob + nExtra;
+  pParse->aBlob = 0;
+  if( jsonBlobExpand(pParse, nSize) ){
+    return 0;
+  }
+  assert( pParse->nBlobAlloc >= pParse->nBlob + nExtra );
+  memcpy(pParse->aBlob, aOld, pParse->nBlob);
+  return 1;
+}
+
+/* Expand pParse->aBlob and append one bytes.
+*/
+static SQLITE_NOINLINE void jsonBlobExpandAndAppendOneByte(
+  JsonParse *pParse,
+  u8 c
+){
+  jsonBlobExpand(pParse, pParse->nBlob+1);
+  if( pParse->oom==0 ){
+    assert( pParse->nBlob+1<=pParse->nBlobAlloc );
+    pParse->aBlob[pParse->nBlob++] = c;
+  }
+}
+
+/* Append a single character.
+*/
+static void jsonBlobAppendOneByte(JsonParse *pParse, u8 c){
+  if( pParse->nBlob >= pParse->nBlobAlloc ){
+    jsonBlobExpandAndAppendOneByte(pParse, c);
+  }else{
+    pParse->aBlob[pParse->nBlob++] = c;
+  }
+}
+
+/* Slow version of jsonBlobAppendNode() that first resizes the
+** pParse->aBlob structure.
+*/
+static void jsonBlobAppendNode(JsonParse*,u8,u32,const void*);
+static SQLITE_NOINLINE void jsonBlobExpandAndAppendNode(
+  JsonParse *pParse,
+  u8 eType,
+  u32 szPayload,
+  const void *aPayload
+){
+  if( jsonBlobExpand(pParse, pParse->nBlob+szPayload+9) ) return;
+  jsonBlobAppendNode(pParse, eType, szPayload, aPayload);
+}
+
+
+/* Append an node type byte together with the payload size and
+** possibly also the payload.
+**
+** If aPayload is not NULL, then it is a pointer to the payload which
+** is also appended.  If aPayload is NULL, the pParse->aBlob[] array
+** is resized (if necessary) so that it is big enough to hold the
+** payload, but the payload is not appended and pParse->nBlob is left
+** pointing to where the first byte of payload will eventually be.
+*/
+static void jsonBlobAppendNode(
+  JsonParse *pParse,          /* The JsonParse object under construction */
+  u8 eType,                   /* Node type.  One of JSONB_* */
+  u32 szPayload,              /* Number of bytes of payload */
+  const void *aPayload        /* The payload.  Might be NULL */
+){
+  u8 *a;
+  if( pParse->nBlob+szPayload+9 > pParse->nBlobAlloc ){
+    jsonBlobExpandAndAppendNode(pParse,eType,szPayload,aPayload);
+    return;
+  }
+  assert( pParse->aBlob!=0 );
+  a = &pParse->aBlob[pParse->nBlob];
+  if( szPayload<=11 ){
+    a[0] = eType | (szPayload<<4);
+    pParse->nBlob += 1;
+  }else if( szPayload<=0xff ){
+    a[0] = eType | 0xc0;
+    a[1] = szPayload & 0xff;
+    pParse->nBlob += 2;
+  }else if( szPayload<=0xffff ){
+    a[0] = eType | 0xd0;
+    a[1] = (szPayload >> 8) & 0xff;
+    a[2] = szPayload & 0xff;
+    pParse->nBlob += 3;
+  }else{
+    a[0] = eType | 0xe0;
+    a[1] = (szPayload >> 24) & 0xff;
+    a[2] = (szPayload >> 16) & 0xff;
+    a[3] = (szPayload >> 8) & 0xff;
+    a[4] = szPayload & 0xff;
+    pParse->nBlob += 5;
+  }
+  if( aPayload ){
+    pParse->nBlob += szPayload;
+    memcpy(&pParse->aBlob[pParse->nBlob-szPayload], aPayload, szPayload);
+  }
+}
+
+/* Change the payload size for the node at index i to be szPayload.
+*/
+static int jsonBlobChangePayloadSize(
+  JsonParse *pParse,
+  u32 i,
+  u32 szPayload
+){
+  u8 *a;
+  u8 szType;
+  u8 nExtra;
+  u8 nNeeded;
+  int delta;
+  if( pParse->oom ) return 0;
+  a = &pParse->aBlob[i];
+  szType = a[0]>>4;
+  if( szType<=11 ){
+    nExtra = 0;
+  }else if( szType==12 ){
+    nExtra = 1;
+  }else if( szType==13 ){
+    nExtra = 2;
+  }else{
+    nExtra = 4;
+  }
+  if( szPayload<=11 ){
+    nNeeded = 0;
+  }else if( szPayload<=0xff ){
+    nNeeded = 1;
+  }else if( szPayload<=0xffff ){
+    nNeeded = 2;
+  }else{
+    nNeeded = 4;
+  }
+  delta = nNeeded - nExtra;
+  if( delta ){
+    u32 newSize = pParse->nBlob + delta;
+    if( delta>0 ){
+      if( newSize>pParse->nBlobAlloc && jsonBlobExpand(pParse, newSize) ){
+        return 0;  /* OOM error.  Error state recorded in pParse->oom. */
+      }
+      a = &pParse->aBlob[i];
+      memmove(&a[1+delta], &a[1], pParse->nBlob - (i+1));
+    }else{
+      memmove(&a[1], &a[1-delta], pParse->nBlob - (i+1-delta));
+    }
+    pParse->nBlob = newSize;
+  }
+  if( nNeeded==0 ){
+    a[0] = (a[0] & 0x0f) | (szPayload<<4);
+  }else if( nNeeded==1 ){
+    a[0] = (a[0] & 0x0f) | 0xc0;
+    a[1] = szPayload & 0xff;
+  }else if( nNeeded==2 ){
+    a[0] = (a[0] & 0x0f) | 0xd0;
+    a[1] = (szPayload >> 8) & 0xff;
+    a[2] = szPayload & 0xff;
+  }else{
+    a[0] = (a[0] & 0x0f) | 0xe0;
+    a[1] = (szPayload >> 24) & 0xff;
+    a[2] = (szPayload >> 16) & 0xff;
+    a[3] = (szPayload >> 8) & 0xff;
+    a[4] = szPayload & 0xff;
+  }
+  return delta;
+}
+
+/*
+** If z[0] is 'u' and is followed by exactly 4 hexadecimal character,
+** then set *pOp to JSONB_TEXTJ and return true.  If not, do not make
+** any changes to *pOp and return false.
+*/
+static int jsonIs4HexB(const char *z, int *pOp){
+  if( z[0]!='u' ) return 0;
+  if( !jsonIs4Hex(&z[1]) ) return 0;
+  *pOp = JSONB_TEXTJ;
+  return 1;
+}
+
+/*
+** Check a single element of the JSONB in pParse for validity.
+**
+** The element to be checked starts at offset i and must end at on the
+** last byte before iEnd.
+**
+** Return 0 if everything is correct.  Return the 1-based byte offset of the
+** error if a problem is detected.  (In other words, if the error is at offset
+** 0, return 1).
+*/
+static u32 jsonbValidityCheck(
+  const JsonParse *pParse,    /* Input JSONB.  Only aBlob and nBlob are used */
+  u32 i,                      /* Start of element as pParse->aBlob[i] */
+  u32 iEnd,                   /* One more than the last byte of the element */
+  u32 iDepth                  /* Current nesting depth */
+){
+  u32 n, sz, j, k;
+  const u8 *z;
+  u8 x;
+  if( iDepth>JSON_MAX_DEPTH ) return i+1;
+  sz = 0;
+  n = jsonbPayloadSize(pParse, i, &sz);
+  if( NEVER(n==0) ) return i+1;          /* Checked by caller */
+  if( NEVER(i+n+sz!=iEnd) ) return i+1;  /* Checked by caller */
+  z = pParse->aBlob;
+  x = z[i] & 0x0f;
+  switch( x ){
+    case JSONB_NULL:
+    case JSONB_TRUE:
+    case JSONB_FALSE: {
+      return n+sz==1 ? 0 : i+1;
+    }
+    case JSONB_INT: {
+      if( sz<1 ) return i+1;
+      j = i+n;
+      if( z[j]=='-' ){
+        j++;
+        if( sz<2 ) return i+1;
+      }
+      k = i+n+sz;
+      while( j<k ){
+        if( sqlite3Isdigit(z[j]) ){
+          j++;
+        }else{
+          return j+1;
+        }
+      }
+      return 0;
+    }
+    case JSONB_INT5: {
+      if( sz<3 ) return i+1;
+      j = i+n;
+      if( z[j]=='-' ){
+        if( sz<4 ) return i+1;
+        j++;
+      }
+      if( z[j]!='0' ) return i+1;
+      if( z[j+1]!='x' && z[j+1]!='X' ) return j+2;
+      j += 2;
+      k = i+n+sz;
+      while( j<k ){
+        if( sqlite3Isxdigit(z[j]) ){
+          j++;
+        }else{
+          return j+1;
+        }
+      }
+      return 0;
+    }
+    case JSONB_FLOAT:
+    case JSONB_FLOAT5: {
+      u8 seen = 0;   /* 0: initial.  1: '.' seen  2: 'e' seen */
+      if( sz<2 ) return i+1;
+      j = i+n;
+      k = j+sz;
+      if( z[j]=='-' ){
+        j++;
+        if( sz<3 ) return i+1;
+      }
+      if( z[j]=='.' ){
+        if( x==JSONB_FLOAT ) return j+1;
+        if( !sqlite3Isdigit(z[j+1]) ) return j+1;
+        j += 2;
+        seen = 1;
+      }else if( z[j]=='0' && x==JSONB_FLOAT ){
+        if( j+3>k ) return j+1;
+        if( z[j+1]!='.' && z[j+1]!='e' && z[j+1]!='E' ) return j+1;
+        j++;
+      }
+      for(; j<k; j++){
+        if( sqlite3Isdigit(z[j]) ) continue;
+        if( z[j]=='.' ){
+          if( seen>0 ) return j+1;
+          if( x==JSONB_FLOAT && (j==k-1 || !sqlite3Isdigit(z[j+1])) ){
+            return j+1;
+          }
+          seen = 1;
+          continue;
+        }
+        if( z[j]=='e' || z[j]=='E' ){
+          if( seen==2 ) return j+1;
+          if( j==k-1 ) return j+1;
+          if( z[j+1]=='+' || z[j+1]=='-' ){
+            j++;
+            if( j==k-1 ) return j+1;
+          }
+          seen = 2;
+          continue;
+        }
+        return j+1;
+      }
+      if( seen==0 ) return i+1;
+      return 0;
+    }
+    case JSONB_TEXT: {
+      j = i+n;
+      k = j+sz;
+      while( j<k ){
+        if( !jsonIsOk[z[j]] && z[j]!='\'' ) return j+1;
+        j++;
+      }
+      return 0;
+    }
+    case JSONB_TEXTJ:
+    case JSONB_TEXT5: {
+      j = i+n;
+      k = j+sz;
+      while( j<k ){
+        if( !jsonIsOk[z[j]] && z[j]!='\'' ){
+          if( z[j]=='"' ){
+            if( x==JSONB_TEXTJ ) return j+1;
+          }else if( z[j]<=0x1f ){
+            /* Control characters in JSON5 string literals are ok */
+            if( x==JSONB_TEXTJ ) return j+1;
+          }else if( NEVER(z[j]!='\\') || j+1>=k ){
+            return j+1;
+          }else if( strchr("\"\\/bfnrt",z[j+1])!=0 ){
+            j++;
+          }else if( z[j+1]=='u' ){
+            if( j+5>=k ) return j+1;
+            if( !jsonIs4Hex((const char*)&z[j+2]) ) return j+1;
+            j++;
+          }else if( x!=JSONB_TEXT5 ){
+            return j+1;
+          }else{
+            u32 c = 0;
+            u32 szC = jsonUnescapeOneChar((const char*)&z[j], k-j, &c);
+            if( c==JSON_INVALID_CHAR ) return j+1;
+            j += szC - 1;
+          }
+        }
+        j++;
+      }
+      return 0;
+    }
+    case JSONB_TEXTRAW: {
+      return 0;
+    }
+    case JSONB_ARRAY: {
+      u32 sub;
+      j = i+n;
+      k = j+sz;
+      while( j<k ){
+        sz = 0;
+        n = jsonbPayloadSize(pParse, j, &sz);
+        if( n==0 ) return j+1;
+        if( j+n+sz>k ) return j+1;
+        sub = jsonbValidityCheck(pParse, j, j+n+sz, iDepth+1);
+        if( sub ) return sub;
+        j += n + sz;
+      }
+      assert( j==k );
+      return 0;
+    }
+    case JSONB_OBJECT: {
+      u32 cnt = 0;
+      u32 sub;
+      j = i+n;
+      k = j+sz;
+      while( j<k ){
+        sz = 0;
+        n = jsonbPayloadSize(pParse, j, &sz);
+        if( n==0 ) return j+1;
+        if( j+n+sz>k ) return j+1;
+        if( (cnt & 1)==0 ){
+          x = z[j] & 0x0f;
+          if( x<JSONB_TEXT || x>JSONB_TEXTRAW ) return j+1;
+        }
+        sub = jsonbValidityCheck(pParse, j, j+n+sz, iDepth+1);
+        if( sub ) return sub;
+        cnt++;
+        j += n + sz;
+      }
+      assert( j==k );
+      if( (cnt & 1)!=0 ) return j+1;
+      return 0;
+    }
+    default: {
+      return i+1;
+    }
+  }
+}
+
+/*
+** Translate a single element of JSON text at pParse->zJson[i] into
+** its equivalent binary JSONB representation.  Append the translation into
+** pParse->aBlob[] beginning at pParse->nBlob.  The size of
+** pParse->aBlob[] is increased as necessary.
+**
+** Return the index of the first character past the end of the element parsed,
+** or one of the following special result codes:
+**
+**      0    End of input
+**     -1    Syntax error or OOM
+**     -2    '}' seen   \
+**     -3    ']' seen    \___  For these returns, pParse->iErr is set to
+**     -4    ',' seen    /     the index in zJson[] of the seen character
+**     -5    ':' seen   /
+*/
+static int jsonTranslateTextToBlob(JsonParse *pParse, u32 i){
+  char c;
+  u32 j;
+  u32 iThis, iStart;
+  int x;
+  u8 t;
+  const char *z = pParse->zJson;
+json_parse_restart:
+  switch( (u8)z[i] ){
+  case '{': {
+    /* Parse object */
+    iThis = pParse->nBlob;
+    jsonBlobAppendNode(pParse, JSONB_OBJECT, pParse->nJson-i, 0);
+    if( ++pParse->iDepth > JSON_MAX_DEPTH ){
+      pParse->iErr = i;
+      return -1;
+    }
+    iStart = pParse->nBlob;
+    for(j=i+1;;j++){
+      u32 iBlob = pParse->nBlob;
+      x = jsonTranslateTextToBlob(pParse, j);
+      if( x<=0 ){
+        int op;
+        if( x==(-2) ){
+          j = pParse->iErr;
+          if( pParse->nBlob!=(u32)iStart ) pParse->hasNonstd = 1;
+          break;
+        }
+        j += json5Whitespace(&z[j]);
+        op = JSONB_TEXT;
+        if( sqlite3JsonId1(z[j])
+         || (z[j]=='\\' && jsonIs4HexB(&z[j+1], &op))
+        ){
+          int k = j+1;
+          while( (sqlite3JsonId2(z[k]) && json5Whitespace(&z[k])==0)
+            || (z[k]=='\\' && jsonIs4HexB(&z[k+1], &op))
+          ){
+            k++;
+          }
+          assert( iBlob==pParse->nBlob );
+          jsonBlobAppendNode(pParse, op, k-j, &z[j]);
+          pParse->hasNonstd = 1;
+          x = k;
+        }else{
+          if( x!=-1 ) pParse->iErr = j;
+          return -1;
+        }
+      }
+      if( pParse->oom ) return -1;
+      t = pParse->aBlob[iBlob] & 0x0f;
+      if( t<JSONB_TEXT || t>JSONB_TEXTRAW ){
+        pParse->iErr = j;
+        return -1;
+      }
+      j = x;
+      if( z[j]==':' ){
+        j++;
+      }else{
+        if( jsonIsspace(z[j]) ){
+          /* strspn() is not helpful here */
+          do{ j++; }while( jsonIsspace(z[j]) );
+          if( z[j]==':' ){
+            j++;
+            goto parse_object_value;
+          }
+        }
+        x = jsonTranslateTextToBlob(pParse, j);
+        if( x!=(-5) ){
+          if( x!=(-1) ) pParse->iErr = j;
+          return -1;
+        }
+        j = pParse->iErr+1;
+      }
+    parse_object_value:
+      x = jsonTranslateTextToBlob(pParse, j);
+      if( x<=0 ){
+        if( x!=(-1) ) pParse->iErr = j;
+        return -1;
+      }
+      j = x;
+      if( z[j]==',' ){
+        continue;
+      }else if( z[j]=='}' ){
+        break;
+      }else{
+        if( jsonIsspace(z[j]) ){
+          j += 1 + (u32)strspn(&z[j+1], jsonSpaces);
+          if( z[j]==',' ){
+            continue;
+          }else if( z[j]=='}' ){
+            break;
+          }
+        }
+        x = jsonTranslateTextToBlob(pParse, j);
+        if( x==(-4) ){
+          j = pParse->iErr;
+          continue;
+        }
+        if( x==(-2) ){
+          j = pParse->iErr;
+          break;
+        }
+      }
+      pParse->iErr = j;
+      return -1;
+    }
+    jsonBlobChangePayloadSize(pParse, iThis, pParse->nBlob - iStart);
+    pParse->iDepth--;
+    return j+1;
+  }
+  case '[': {
+    /* Parse array */
+    iThis = pParse->nBlob;
+    assert( i<=(u32)pParse->nJson );
+    jsonBlobAppendNode(pParse, JSONB_ARRAY, pParse->nJson - i, 0);
+    iStart = pParse->nBlob;
+    if( pParse->oom ) return -1;
+    if( ++pParse->iDepth > JSON_MAX_DEPTH ){
+      pParse->iErr = i;
+      return -1;
+    }
+    for(j=i+1;;j++){
+      x = jsonTranslateTextToBlob(pParse, j);
+      if( x<=0 ){
+        if( x==(-3) ){
+          j = pParse->iErr;
+          if( pParse->nBlob!=iStart ) pParse->hasNonstd = 1;
+          break;
+        }
+        if( x!=(-1) ) pParse->iErr = j;
+        return -1;
+      }
+      j = x;
+      if( z[j]==',' ){
+        continue;
+      }else if( z[j]==']' ){
+        break;
+      }else{
+        if( jsonIsspace(z[j]) ){
+          j += 1 + (u32)strspn(&z[j+1], jsonSpaces);
+          if( z[j]==',' ){
+            continue;
+          }else if( z[j]==']' ){
+            break;
+          }
+        }
+        x = jsonTranslateTextToBlob(pParse, j);
+        if( x==(-4) ){
+          j = pParse->iErr;
+          continue;
+        }
+        if( x==(-3) ){
+          j = pParse->iErr;
+          break;
+        }
+      }
+      pParse->iErr = j;
+      return -1;
+    }
+    jsonBlobChangePayloadSize(pParse, iThis, pParse->nBlob - iStart);
+    pParse->iDepth--;
+    return j+1;
+  }
+  case '\'': {
+    u8 opcode;
+    char cDelim;
+    pParse->hasNonstd = 1;
+    opcode = JSONB_TEXT;
+    goto parse_string;
+  case '"':
+    /* Parse string */
+    opcode = JSONB_TEXT;
+  parse_string:
+    cDelim = z[i];
+    j = i+1;
+    while( 1 /*exit-by-break*/ ){
+      if( jsonIsOk[(u8)z[j]] ){
+        if( !jsonIsOk[(u8)z[j+1]] ){
+          j += 1;
+        }else if( !jsonIsOk[(u8)z[j+2]] ){
+          j += 2;
+        }else{
+          j += 3;
+          continue;
+        }
+      }
+      c = z[j];
+      if( c==cDelim ){
+        break;
+      }else if( c=='\\' ){
+        c = z[++j];
+        if( c=='"' || c=='\\' || c=='/' || c=='b' || c=='f'
+           || c=='n' || c=='r' || c=='t'
+           || (c=='u' && jsonIs4Hex(&z[j+1])) ){
+          if( opcode==JSONB_TEXT ) opcode = JSONB_TEXTJ;
+        }else if( c=='\'' || c=='0' || c=='v' || c=='\n'
+           || (0xe2==(u8)c && 0x80==(u8)z[j+1]
+                && (0xa8==(u8)z[j+2] || 0xa9==(u8)z[j+2]))
+           || (c=='x' && jsonIs2Hex(&z[j+1])) ){
+          opcode = JSONB_TEXT5;
+          pParse->hasNonstd = 1;
+        }else if( c=='\r' ){
+          if( z[j+1]=='\n' ) j++;
+          opcode = JSONB_TEXT5;
+          pParse->hasNonstd = 1;
+        }else{
+          pParse->iErr = j;
+          return -1;
+        }
+      }else if( c<=0x1f ){
+        if( c==0 ){
+          pParse->iErr = j;
+          return -1;
+        }
+        /* Control characters are not allowed in canonical JSON string
+        ** literals, but are allowed in JSON5 string literals. */
+        opcode = JSONB_TEXT5;
+        pParse->hasNonstd = 1;
+      }else if( c=='"' ){
+        opcode = JSONB_TEXT5;
+      }
+      j++;
+    }
+    jsonBlobAppendNode(pParse, opcode, j-1-i, &z[i+1]);
+    return j+1;
+  }
+  case 't': {
+    if( strncmp(z+i,"true",4)==0 && !sqlite3Isalnum(z[i+4]) ){
+      jsonBlobAppendOneByte(pParse, JSONB_TRUE);
+      return i+4;
+    }
+    pParse->iErr = i;
+    return -1;
+  }
+  case 'f': {
+    if( strncmp(z+i,"false",5)==0 && !sqlite3Isalnum(z[i+5]) ){
+      jsonBlobAppendOneByte(pParse, JSONB_FALSE);
+      return i+5;
+    }
+    pParse->iErr = i;
+    return -1;
+  }
+  case '+': {
+    u8 seenE;
+    pParse->hasNonstd = 1;
+    t = 0x00;            /* Bit 0x01:  JSON5.   Bit 0x02:  FLOAT */
+    goto parse_number;
+  case '.':
+    if( sqlite3Isdigit(z[i+1]) ){
+      pParse->hasNonstd = 1;
+      t = 0x03;          /* Bit 0x01:  JSON5.   Bit 0x02:  FLOAT */
+      seenE = 0;
+      goto parse_number_2;
+    }
+    pParse->iErr = i;
+    return -1;
+  case '-':
+  case '0':
+  case '1':
+  case '2':
+  case '3':
+  case '4':
+  case '5':
+  case '6':
+  case '7':
+  case '8':
+  case '9':
+    /* Parse number */
+    t = 0x00;            /* Bit 0x01:  JSON5.   Bit 0x02:  FLOAT */
+  parse_number:
+    seenE = 0;
+    assert( '-' < '0' );
+    assert( '+' < '0' );
+    assert( '.' < '0' );
+    c = z[i];
+
+    if( c<='0' ){
+      if( c=='0' ){
+        if( (z[i+1]=='x' || z[i+1]=='X') && sqlite3Isxdigit(z[i+2]) ){
+          assert( t==0x00 );
+          pParse->hasNonstd = 1;
+          t = 0x01;
+          for(j=i+3; sqlite3Isxdigit(z[j]); j++){}
+          goto parse_number_finish;
+        }else if( sqlite3Isdigit(z[i+1]) ){
+          pParse->iErr = i+1;
+          return -1;
+        }
+      }else{
+        if( !sqlite3Isdigit(z[i+1]) ){
+          /* JSON5 allows for "+Infinity" and "-Infinity" using exactly
+          ** that case.  SQLite also allows these in any case and it allows
+          ** "+inf" and "-inf". */
+          if( (z[i+1]=='I' || z[i+1]=='i')
+           && sqlite3StrNICmp(&z[i+1], "inf",3)==0
+          ){
+            pParse->hasNonstd = 1;
+            if( z[i]=='-' ){
+              jsonBlobAppendNode(pParse, JSONB_FLOAT, 6, "-9e999");
+            }else{
+              jsonBlobAppendNode(pParse, JSONB_FLOAT, 5, "9e999");
+            }
+            return i + (sqlite3StrNICmp(&z[i+4],"inity",5)==0 ? 9 : 4);
+          }
+          if( z[i+1]=='.' ){
+            pParse->hasNonstd = 1;
+            t |= 0x01;
+            goto parse_number_2;
+          }
+          pParse->iErr = i;
+          return -1;
+        }
+        if( z[i+1]=='0' ){
+          if( sqlite3Isdigit(z[i+2]) ){
+            pParse->iErr = i+1;
+            return -1;
+          }else if( (z[i+2]=='x' || z[i+2]=='X') && sqlite3Isxdigit(z[i+3]) ){
+            pParse->hasNonstd = 1;
+            t |= 0x01;
+            for(j=i+4; sqlite3Isxdigit(z[j]); j++){}
+            goto parse_number_finish;
+          }
+        }
+      }
+    }
+
+  parse_number_2:
+    for(j=i+1;; j++){
+      c = z[j];
+      if( sqlite3Isdigit(c) ) continue;
+      if( c=='.' ){
+        if( (t & 0x02)!=0 ){
+          pParse->iErr = j;
+          return -1;
+        }
+        t |= 0x02;
+        continue;
+      }
+      if( c=='e' || c=='E' ){
+        if( z[j-1]<'0' ){
+          if( ALWAYS(z[j-1]=='.') && ALWAYS(j-2>=i) && sqlite3Isdigit(z[j-2]) ){
+            pParse->hasNonstd = 1;
+            t |= 0x01;
+          }else{
+            pParse->iErr = j;
+            return -1;
+          }
+        }
+        if( seenE ){
+          pParse->iErr = j;
+          return -1;
+        }
+        t |= 0x02;
+        seenE = 1;
+        c = z[j+1];
+        if( c=='+' || c=='-' ){
+          j++;
+          c = z[j+1];
+        }
+        if( c<'0' || c>'9' ){
+          pParse->iErr = j;
+          return -1;
+        }
+        continue;
+      }
+      break;
+    }
+    if( z[j-1]<'0' ){
+      if( ALWAYS(z[j-1]=='.') && ALWAYS(j-2>=i) && sqlite3Isdigit(z[j-2]) ){
+        pParse->hasNonstd = 1;
+        t |= 0x01;
+      }else{
+        pParse->iErr = j;
+        return -1;
+      }
+    }
+  parse_number_finish:
+    assert( JSONB_INT+0x01==JSONB_INT5 );
+    assert( JSONB_FLOAT+0x01==JSONB_FLOAT5 );
+    assert( JSONB_INT+0x02==JSONB_FLOAT );
+    if( z[i]=='+' ) i++;
+    jsonBlobAppendNode(pParse, JSONB_INT+t, j-i, &z[i]);
+    return j;
+  }
+  case '}': {
+    pParse->iErr = i;
+    return -2;  /* End of {...} */
+  }
+  case ']': {
+    pParse->iErr = i;
+    return -3;  /* End of [...] */
+  }
+  case ',': {
+    pParse->iErr = i;
+    return -4;  /* List separator */
+  }
+  case ':': {
+    pParse->iErr = i;
+    return -5;  /* Object label/value separator */
+  }
+  case 0: {
+    return 0;   /* End of file */
+  }
+  case 0x09:
+  case 0x0a:
+  case 0x0d:
+  case 0x20: {
+    i += 1 + (u32)strspn(&z[i+1], jsonSpaces);
+    goto json_parse_restart;
+  }
+  case 0x0b:
+  case 0x0c:
+  case '/':
+  case 0xc2:
+  case 0xe1:
+  case 0xe2:
+  case 0xe3:
+  case 0xef: {
+    j = json5Whitespace(&z[i]);
+    if( j>0 ){
+      i += j;
+      pParse->hasNonstd = 1;
+      goto json_parse_restart;
+    }
+    pParse->iErr = i;
+    return -1;
+  }
+  case 'n': {
+    if( strncmp(z+i,"null",4)==0 && !sqlite3Isalnum(z[i+4]) ){
+      jsonBlobAppendOneByte(pParse, JSONB_NULL);
+      return i+4;
+    }
+    /* fall-through into the default case that checks for NaN */
+    /* no break */ deliberate_fall_through
+  }
+  default: {
+    u32 k;
+    int nn;
+    c = z[i];
+    for(k=0; k<sizeof(aNanInfName)/sizeof(aNanInfName[0]); k++){
+      if( c!=aNanInfName[k].c1 && c!=aNanInfName[k].c2 ) continue;
+      nn = aNanInfName[k].n;
+      if( sqlite3StrNICmp(&z[i], aNanInfName[k].zMatch, nn)!=0 ){
+        continue;
+      }
+      if( sqlite3Isalnum(z[i+nn]) ) continue;
+      if( aNanInfName[k].eType==JSONB_FLOAT ){
+        jsonBlobAppendNode(pParse, JSONB_FLOAT, 5, "9e999");
+      }else{
+        jsonBlobAppendOneByte(pParse, JSONB_NULL);
+      }
+      pParse->hasNonstd = 1;
+      return i + nn;
+    }
+    pParse->iErr = i;
+    return -1;  /* Syntax error */
+  }
+  } /* End switch(z[i]) */
+}
+
+
+/*
+** Parse a complete JSON string.  Return 0 on success or non-zero if there
+** are any errors.  If an error occurs, free all memory held by pParse,
+** but not pParse itself.
+**
+** pParse must be initialized to an empty parse object prior to calling
+** this routine.
+*/
+static int jsonConvertTextToBlob(
+  JsonParse *pParse,           /* Initialize and fill this JsonParse object */
+  sqlite3_context *pCtx        /* Report errors here */
+){
+  int i;
+  const char *zJson = pParse->zJson;
+  i = jsonTranslateTextToBlob(pParse, 0);
+  if( pParse->oom ) i = -1;
+  if( i>0 ){
+#ifdef SQLITE_DEBUG
+    assert( pParse->iDepth==0 );
+    if( sqlite3Config.bJsonSelfcheck ){
+      assert( jsonbValidityCheck(pParse, 0, pParse->nBlob, 0)==0 );
+    }
+#endif
+    while( jsonIsspace(zJson[i]) ) i++;
+    if( zJson[i] ){
+      i += json5Whitespace(&zJson[i]);
+      if( zJson[i] ){
+        if( pCtx ) sqlite3_result_error(pCtx, "malformed JSON", -1);
+        jsonParseReset(pParse);
+        return 1;
+      }
+      pParse->hasNonstd = 1;
+    }
+  }
+  if( i<=0 ){
+    if( pCtx!=0 ){
+      if( pParse->oom ){
+        sqlite3_result_error_nomem(pCtx);
+      }else{
+        sqlite3_result_error(pCtx, "malformed JSON", -1);
+      }
+    }
+    jsonParseReset(pParse);
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** The input string pStr is a well-formed JSON text string.  Convert
+** this into the JSONB format and make it the return value of the
+** SQL function.
+*/
+static void jsonReturnStringAsBlob(JsonString *pStr){
+  JsonParse px;
+  memset(&px, 0, sizeof(px));
+  jsonStringTerminate(pStr);
+  if( pStr->eErr ){
+    sqlite3_result_error_nomem(pStr->pCtx);
+    return;
+  }
+  px.zJson = pStr->zBuf;
+  px.nJson = pStr->nUsed;
+  px.db = sqlite3_context_db_handle(pStr->pCtx);
+  (void)jsonTranslateTextToBlob(&px, 0);
+  if( px.oom ){
+    sqlite3DbFree(px.db, px.aBlob);
+    sqlite3_result_error_nomem(pStr->pCtx);
+  }else{
+    assert( px.nBlobAlloc>0 );
+    assert( !px.bReadOnly );
+    sqlite3_result_blob(pStr->pCtx, px.aBlob, px.nBlob, SQLITE_DYNAMIC);
+  }
+}
+
+/* The byte at index i is a node type-code.  This routine
+** determines the payload size for that node and writes that
+** payload size in to *pSz.  It returns the offset from i to the
+** beginning of the payload.  Return 0 on error.
+*/
+static u32 jsonbPayloadSize(const JsonParse *pParse, u32 i, u32 *pSz){
+  u8 x;
+  u32 sz;
+  u32 n;
+  if( NEVER(i>pParse->nBlob) ){
+    *pSz = 0;
+    return 0;
+  }
+  x = pParse->aBlob[i]>>4;
+  if( x<=11 ){
+    sz = x;
+    n = 1;
+  }else if( x==12 ){
+    if( i+1>=pParse->nBlob ){
+      *pSz = 0;
+      return 0;
+    }
+    sz = pParse->aBlob[i+1];
+    n = 2;
+  }else if( x==13 ){
+    if( i+2>=pParse->nBlob ){
+      *pSz = 0;
+      return 0;
+    }
+    sz = (pParse->aBlob[i+1]<<8) + pParse->aBlob[i+2];
+    n = 3;
+  }else if( x==14 ){
+    if( i+4>=pParse->nBlob ){
+      *pSz = 0;
+      return 0;
+    }
+    sz = ((u32)pParse->aBlob[i+1]<<24) + (pParse->aBlob[i+2]<<16) +
+         (pParse->aBlob[i+3]<<8) + pParse->aBlob[i+4];
+    n = 5;
+  }else{
+    if( i+8>=pParse->nBlob
+     || pParse->aBlob[i+1]!=0
+     || pParse->aBlob[i+2]!=0
+     || pParse->aBlob[i+3]!=0
+     || pParse->aBlob[i+4]!=0
+    ){
+      *pSz = 0;
+      return 0;
+    }
+    sz = (pParse->aBlob[i+5]<<24) + (pParse->aBlob[i+6]<<16) +
+         (pParse->aBlob[i+7]<<8) + pParse->aBlob[i+8];
+    n = 9;
+  }
+  if( (i64)i+sz+n > pParse->nBlob
+   && (i64)i+sz+n > pParse->nBlob-pParse->delta
+  ){
+    sz = 0;
+    n = 0;
+  }
+  *pSz = sz;
+  return n;
+}
+
+
+/*
+** Translate the binary JSONB representation of JSON beginning at
+** pParse->aBlob[i] into a JSON text string.  Append the JSON
+** text onto the end of pOut.  Return the index in pParse->aBlob[]
+** of the first byte past the end of the element that is translated.
+**
+** If an error is detected in the BLOB input, the pOut->eErr flag
+** might get set to JSTRING_MALFORMED.  But not all BLOB input errors
+** are detected.  So a malformed JSONB input might either result
+** in an error, or in incorrect JSON.
+**
+** The pOut->eErr JSTRING_OOM flag is set on a OOM.
+*/
+static u32 jsonTranslateBlobToText(
+  const JsonParse *pParse,       /* the complete parse of the JSON */
+  u32 i,                         /* Start rendering at this index */
+  JsonString *pOut               /* Write JSON here */
+){
+  u32 sz, n, j, iEnd;
+
+  n = jsonbPayloadSize(pParse, i, &sz);
+  if( n==0 ){
+    pOut->eErr |= JSTRING_MALFORMED;
+    return pParse->nBlob+1;
+  }
+  switch( pParse->aBlob[i] & 0x0f ){
+    case JSONB_NULL: {
+      jsonAppendRawNZ(pOut, "null", 4);
+      return i+1;
+    }
+    case JSONB_TRUE: {
+      jsonAppendRawNZ(pOut, "true", 4);
+      return i+1;
+    }
+    case JSONB_FALSE: {
+      jsonAppendRawNZ(pOut, "false", 5);
+      return i+1;
+    }
+    case JSONB_INT:
+    case JSONB_FLOAT: {
+      if( sz==0 ) goto malformed_jsonb;
+      jsonAppendRaw(pOut, (const char*)&pParse->aBlob[i+n], sz);
+      break;
+    }
+    case JSONB_INT5: {  /* Integer literal in hexadecimal notation */
+      u32 k = 2;
+      sqlite3_uint64 u = 0;
+      const char *zIn = (const char*)&pParse->aBlob[i+n];
+      int bOverflow = 0;
+      if( sz==0 ) goto malformed_jsonb;
+      if( zIn[0]=='-' ){
+        jsonAppendChar(pOut, '-');
+        k++;
+      }else if( zIn[0]=='+' ){
+        k++;
+      }
+      for(; k<sz; k++){
+        if( !sqlite3Isxdigit(zIn[k]) ){
+          pOut->eErr |= JSTRING_MALFORMED;
+          break;
+        }else if( (u>>60)!=0 ){
+          bOverflow = 1;
+        }else{
+          u = u*16 + sqlite3HexToInt(zIn[k]);
+        }
+      }
+      jsonPrintf(100,pOut,bOverflow?"9.0e999":"%llu", u);
+      break;
+    }
+    case JSONB_FLOAT5: { /* Float literal missing digits beside "." */
+      u32 k = 0;
+      const char *zIn = (const char*)&pParse->aBlob[i+n];
+      if( sz==0 ) goto malformed_jsonb;
+      if( zIn[0]=='-' ){
+        jsonAppendChar(pOut, '-');
+        k++;
+      }
+      if( zIn[k]=='.' ){
+        jsonAppendChar(pOut, '0');
+      }
+      for(; k<sz; k++){
+        jsonAppendChar(pOut, zIn[k]);
+        if( zIn[k]=='.' && (k+1==sz || !sqlite3Isdigit(zIn[k+1])) ){
+          jsonAppendChar(pOut, '0');
+        }
+      }
+      break;
+    }
+    case JSONB_TEXT:
+    case JSONB_TEXTJ: {
+      jsonAppendChar(pOut, '"');
+      jsonAppendRaw(pOut, (const char*)&pParse->aBlob[i+n], sz);
+      jsonAppendChar(pOut, '"');
+      break;
+    }
+    case JSONB_TEXT5: {
+      const char *zIn;
+      u32 k;
+      u32 sz2 = sz;
+      zIn = (const char*)&pParse->aBlob[i+n];
+      jsonAppendChar(pOut, '"');
+      while( sz2>0 ){
+        for(k=0; k<sz2 && (jsonIsOk[(u8)zIn[k]] || zIn[k]=='\''); k++){}
+        if( k>0 ){
+          jsonAppendRawNZ(pOut, zIn, k);
+          if( k>=sz2 ){
+            break;
+          }
+          zIn += k;
+          sz2 -= k;
+        }
+        if( zIn[0]=='"' ){
+          jsonAppendRawNZ(pOut, "\\\"", 2);
+          zIn++;
+          sz2--;
+          continue;
+        }
+        if( zIn[0]<=0x1f ){
+          if( pOut->nUsed+7>pOut->nAlloc && jsonStringGrow(pOut,7) ) break;
+          jsonAppendControlChar(pOut, zIn[0]);
+          zIn++;
+          sz2--;
+          continue;
+        }
+        assert( zIn[0]=='\\' );
+        assert( sz2>=1 );
+        if( sz2<2 ){
+          pOut->eErr |= JSTRING_MALFORMED;
+          break;
+        }
+        switch( (u8)zIn[1] ){
+          case '\'':
+            jsonAppendChar(pOut, '\'');
+            break;
+          case 'v':
+            jsonAppendRawNZ(pOut, "\\u0009", 6);
+            break;
+          case 'x':
+            if( sz2<4 ){
+              pOut->eErr |= JSTRING_MALFORMED;
+              sz2 = 2;
+              break;
+            }
+            jsonAppendRawNZ(pOut, "\\u00", 4);
+            jsonAppendRawNZ(pOut, &zIn[2], 2);
+            zIn += 2;
+            sz2 -= 2;
+            break;
+          case '0':
+            jsonAppendRawNZ(pOut, "\\u0000", 6);
+            break;
+          case '\r':
+            if( sz2>2 && zIn[2]=='\n' ){
+              zIn++;
+              sz2--;
+            }
+            break;
+          case '\n':
+            break;
+          case 0xe2:
+            /* '\' followed by either U+2028 or U+2029 is ignored as
+            ** whitespace.  Not that in UTF8, U+2028 is 0xe2 0x80 0x29.
+            ** U+2029 is the same except for the last byte */
+            if( sz2<4
+             || 0x80!=(u8)zIn[2]
+             || (0xa8!=(u8)zIn[3] && 0xa9!=(u8)zIn[3])
+            ){
+              pOut->eErr |= JSTRING_MALFORMED;
+              sz2 = 2;
+              break;
+            }
+            zIn += 2;
+            sz2 -= 2;
+            break;
+          default:
+            jsonAppendRawNZ(pOut, zIn, 2);
+            break;
+        }
+        assert( sz2>=2 );
+        zIn += 2;
+        sz2 -= 2;
+      }
+      jsonAppendChar(pOut, '"');
+      break;
+    }
+    case JSONB_TEXTRAW: {
+      jsonAppendString(pOut, (const char*)&pParse->aBlob[i+n], sz);
+      break;
+    }
+    case JSONB_ARRAY: {
+      jsonAppendChar(pOut, '[');
+      j = i+n;
+      iEnd = j+sz;
+      while( j<iEnd && pOut->eErr==0 ){
+        j = jsonTranslateBlobToText(pParse, j, pOut);
+        jsonAppendChar(pOut, ',');
+      }
+      if( j>iEnd ) pOut->eErr |= JSTRING_MALFORMED;
+      if( sz>0 ) jsonStringTrimOneChar(pOut);
+      jsonAppendChar(pOut, ']');
+      break;
+    }
+    case JSONB_OBJECT: {
+      int x = 0;
+      jsonAppendChar(pOut, '{');
+      j = i+n;
+      iEnd = j+sz;
+      while( j<iEnd && pOut->eErr==0 ){
+        j = jsonTranslateBlobToText(pParse, j, pOut);
+        jsonAppendChar(pOut, (x++ & 1) ? ',' : ':');
+      }
+      if( (x & 1)!=0 || j>iEnd ) pOut->eErr |= JSTRING_MALFORMED;
+      if( sz>0 ) jsonStringTrimOneChar(pOut);
+      jsonAppendChar(pOut, '}');
+      break;
+    }
+
+    default: {
+      malformed_jsonb:
+      pOut->eErr |= JSTRING_MALFORMED;
+      break;
+    }
+  }
+  return i+n+sz;
+}
+
+/* Context for recursion of json_pretty()
+*/
+typedef struct JsonPretty JsonPretty;
+struct JsonPretty {
+  JsonParse *pParse;        /* The BLOB being rendered */
+  JsonString *pOut;         /* Generate pretty output into this string */
+  const char *zIndent;      /* Use this text for indentation */
+  u32 szIndent;             /* Bytes in zIndent[] */
+  u32 nIndent;              /* Current level of indentation */
+};
+
+/* Append indentation to the pretty JSON under construction */
+static void jsonPrettyIndent(JsonPretty *pPretty){
+  u32 jj;
+  for(jj=0; jj<pPretty->nIndent; jj++){
+    jsonAppendRaw(pPretty->pOut, pPretty->zIndent, pPretty->szIndent);
+  }
+}
+
+/*
+** Translate the binary JSONB representation of JSON beginning at
+** pParse->aBlob[i] into a JSON text string.  Append the JSON
+** text onto the end of pOut.  Return the index in pParse->aBlob[]
+** of the first byte past the end of the element that is translated.
+**
+** This is a variant of jsonTranslateBlobToText() that "pretty-prints"
+** the output.  Extra whitespace is inserted to make the JSON easier
+** for humans to read.
+**
+** If an error is detected in the BLOB input, the pOut->eErr flag
+** might get set to JSTRING_MALFORMED.  But not all BLOB input errors
+** are detected.  So a malformed JSONB input might either result
+** in an error, or in incorrect JSON.
+**
+** The pOut->eErr JSTRING_OOM flag is set on a OOM.
+*/
+static u32 jsonTranslateBlobToPrettyText(
+  JsonPretty *pPretty,       /* Pretty-printing context */
+  u32 i                      /* Start rendering at this index */
+){
+  u32 sz, n, j, iEnd;
+  const JsonParse *pParse = pPretty->pParse;
+  JsonString *pOut = pPretty->pOut;
+  n = jsonbPayloadSize(pParse, i, &sz);
+  if( n==0 ){
+    pOut->eErr |= JSTRING_MALFORMED;
+    return pParse->nBlob+1;
+  }
+  switch( pParse->aBlob[i] & 0x0f ){
+    case JSONB_ARRAY: {
+      j = i+n;
+      iEnd = j+sz;
+      jsonAppendChar(pOut, '[');
+      if( j<iEnd ){
+        jsonAppendChar(pOut, '\n');
+        pPretty->nIndent++;
+        while( pOut->eErr==0 ){
+          jsonPrettyIndent(pPretty);
+          j = jsonTranslateBlobToPrettyText(pPretty, j);
+          if( j>=iEnd ) break;
+          jsonAppendRawNZ(pOut, ",\n", 2);
+        }
+        jsonAppendChar(pOut, '\n');
+        pPretty->nIndent--;
+        jsonPrettyIndent(pPretty);
+      }
+      jsonAppendChar(pOut, ']');
+      i = iEnd;
+      break;
+    }
+    case JSONB_OBJECT: {
+      j = i+n;
+      iEnd = j+sz;
+      jsonAppendChar(pOut, '{');
+      if( j<iEnd ){
+        jsonAppendChar(pOut, '\n');
+        pPretty->nIndent++;
+        while( pOut->eErr==0 ){
+          jsonPrettyIndent(pPretty);
+          j = jsonTranslateBlobToText(pParse, j, pOut);
+          if( j>iEnd ){
+            pOut->eErr |= JSTRING_MALFORMED;
+            break;
+          }
+          jsonAppendRawNZ(pOut, ": ", 2);
+          j = jsonTranslateBlobToPrettyText(pPretty, j);
+          if( j>=iEnd ) break;
+          jsonAppendRawNZ(pOut, ",\n", 2);
+        }
+        jsonAppendChar(pOut, '\n');
+        pPretty->nIndent--;
+        jsonPrettyIndent(pPretty);
+      }
+      jsonAppendChar(pOut, '}');
+      i = iEnd;
+      break;
+    }
+    default: {
+      i = jsonTranslateBlobToText(pParse, i, pOut);
+      break;
+    }
+  }
+  return i;
+}
+
+
+/* Return true if the input pJson
+**
+** For performance reasons, this routine does not do a detailed check of the
+** input BLOB to ensure that it is well-formed.  Hence, false positives are
+** possible.  False negatives should never occur, however.
+*/
+static int jsonFuncArgMightBeBinary(sqlite3_value *pJson){
+  u32 sz, n;
+  const u8 *aBlob;
+  int nBlob;
+  JsonParse s;
+  if( sqlite3_value_type(pJson)!=SQLITE_BLOB ) return 0;
+  aBlob = sqlite3_value_blob(pJson);
+  nBlob = sqlite3_value_bytes(pJson);
+  if( nBlob<1 ) return 0;
+  if( NEVER(aBlob==0) || (aBlob[0] & 0x0f)>JSONB_OBJECT ) return 0;
+  memset(&s, 0, sizeof(s));
+  s.aBlob = (u8*)aBlob;
+  s.nBlob = nBlob;
+  n = jsonbPayloadSize(&s, 0, &sz);
+  if( n==0 ) return 0;
+  if( sz+n!=(u32)nBlob ) return 0;
+  if( (aBlob[0] & 0x0f)<=JSONB_FALSE && sz>0 ) return 0;
+  return sz+n==(u32)nBlob;
+}
+
+/*
+** Given that a JSONB_ARRAY object starts at offset i, return
+** the number of entries in that array.
+*/
+static u32 jsonbArrayCount(JsonParse *pParse, u32 iRoot){
+  u32 n, sz, i, iEnd;
+  u32 k = 0;
+  n = jsonbPayloadSize(pParse, iRoot, &sz);
+  iEnd = iRoot+n+sz;
+  for(i=iRoot+n; n>0 && i<iEnd; i+=sz+n, k++){
+    n = jsonbPayloadSize(pParse, i, &sz);
+  }
+  return k;
+}
+
+/*
+** Edit the payload size of the element at iRoot by the amount in
+** pParse->delta.
+*/
+static void jsonAfterEditSizeAdjust(JsonParse *pParse, u32 iRoot){
+  u32 sz = 0;
+  u32 nBlob;
+  assert( pParse->delta!=0 );
+  assert( pParse->nBlobAlloc >= pParse->nBlob );
+  nBlob = pParse->nBlob;
+  pParse->nBlob = pParse->nBlobAlloc;
+  (void)jsonbPayloadSize(pParse, iRoot, &sz);
+  pParse->nBlob = nBlob;
+  sz += pParse->delta;
+  pParse->delta += jsonBlobChangePayloadSize(pParse, iRoot, sz);
+}
+
+/*
+** Modify the JSONB blob at pParse->aBlob by removing nDel bytes of
+** content beginning at iDel, and replacing them with nIns bytes of
+** content given by aIns.
+**
+** nDel may be zero, in which case no bytes are removed.  But iDel is
+** still important as new bytes will be insert beginning at iDel.
+**
+** aIns may be zero, in which case space is created to hold nIns bytes
+** beginning at iDel, but that space is uninitialized.
+**
+** Set pParse->oom if an OOM occurs.
+*/
+static void jsonBlobEdit(
+  JsonParse *pParse,     /* The JSONB to be modified is in pParse->aBlob */
+  u32 iDel,              /* First byte to be removed */
+  u32 nDel,              /* Number of bytes to remove */
+  const u8 *aIns,        /* Content to insert */
+  u32 nIns               /* Bytes of content to insert */
+){
+  i64 d = (i64)nIns - (i64)nDel;
+  if( d!=0 ){
+    if( pParse->nBlob + d > pParse->nBlobAlloc ){
+      jsonBlobExpand(pParse, pParse->nBlob+d);
+      if( pParse->oom ) return;
+    }
+    memmove(&pParse->aBlob[iDel+nIns],
+            &pParse->aBlob[iDel+nDel],
+            pParse->nBlob - (iDel+nDel));
+    pParse->nBlob += d;
+    pParse->delta += d;
+  }
+  if( nIns && aIns ) memcpy(&pParse->aBlob[iDel], aIns, nIns);
+}
+
+/*
+** Return the number of escaped newlines to be ignored.
+** An escaped newline is a one of the following byte sequences:
+**
+**    0x5c 0x0a
+**    0x5c 0x0d
+**    0x5c 0x0d 0x0a
+**    0x5c 0xe2 0x80 0xa8
+**    0x5c 0xe2 0x80 0xa9
+*/
+static u32 jsonBytesToBypass(const char *z, u32 n){
+  u32 i = 0;
+  while( i+1<n ){
+    if( z[i]!='\\' ) return i;
+    if( z[i+1]=='\n' ){
+      i += 2;
+      continue;
+    }
+    if( z[i+1]=='\r' ){
+      if( i+2<n && z[i+2]=='\n' ){
+        i += 3;
+      }else{
+        i += 2;
+      }
+      continue;
+    }
+    if( 0xe2==(u8)z[i+1]
+     && i+3<n
+     && 0x80==(u8)z[i+2]
+     && (0xa8==(u8)z[i+3] || 0xa9==(u8)z[i+3])
+    ){
+      i += 4;
+      continue;
+    }
+    break;
+  }
+  return i;
+}
+
+/*
+** Input z[0..n] defines JSON escape sequence including the leading '\\'.
+** Decode that escape sequence into a single character.  Write that
+** character into *piOut.  Return the number of bytes in the escape sequence.
+**
+** If there is a syntax error of some kind (for example too few characters
+** after the '\\' to complete the encoding) then *piOut is set to
+** JSON_INVALID_CHAR.
+*/
+static u32 jsonUnescapeOneChar(const char *z, u32 n, u32 *piOut){
+  assert( n>0 );
+  assert( z[0]=='\\' );
+  if( n<2 ){
+    *piOut = JSON_INVALID_CHAR;
+    return n;
+  }
+  switch( (u8)z[1] ){
+    case 'u': {
+      u32 v, vlo;
+      if( n<6 ){
+        *piOut = JSON_INVALID_CHAR;
+        return n;
+      }
+      v = jsonHexToInt4(&z[2]);
+      if( (v & 0xfc00)==0xd800
+       && n>=12
+       && z[6]=='\\'
+       && z[7]=='u'
+       && ((vlo = jsonHexToInt4(&z[8]))&0xfc00)==0xdc00
+      ){
+        *piOut = ((v&0x3ff)<<10) + (vlo&0x3ff) + 0x10000;
+        return 12;
+      }else{
+        *piOut = v;
+        return 6;
+      }
+    }
+    case 'b': {   *piOut = '\b';  return 2; }
+    case 'f': {   *piOut = '\f';  return 2; }
+    case 'n': {   *piOut = '\n';  return 2; }
+    case 'r': {   *piOut = '\r';  return 2; }
+    case 't': {   *piOut = '\t';  return 2; }
+    case 'v': {   *piOut = '\v';  return 2; }
+    case '0': {   *piOut = 0;     return 2; }
+    case '\'':
+    case '"':
+    case '/':
+    case '\\':{   *piOut = z[1];  return 2; }
+    case 'x': {
+      if( n<4 ){
+        *piOut = JSON_INVALID_CHAR;
+        return n;
+      }
+      *piOut = (jsonHexToInt(z[2])<<4) | jsonHexToInt(z[3]);
+      return 4;
+    }
+    case 0xe2:
+    case '\r':
+    case '\n': {
+      u32 nSkip = jsonBytesToBypass(z, n);
+      if( nSkip==0 ){
+        *piOut = JSON_INVALID_CHAR;
+        return n;
+      }else if( nSkip==n ){
+        *piOut = 0;
+        return n;
+      }else if( z[nSkip]=='\\' ){
+        return nSkip + jsonUnescapeOneChar(&z[nSkip], n-nSkip, piOut);
+      }else{
+        int sz = sqlite3Utf8ReadLimited((u8*)&z[nSkip], n-nSkip, piOut);
+        return nSkip + sz;
+      }
+    }
+    default: {
+      *piOut = JSON_INVALID_CHAR;
+      return 2;
+    }
+  }
+}
+
+
+/*
+** Compare two object labels.  Return 1 if they are equal and
+** 0 if they differ.
+**
+** In this version, we know that one or the other or both of the
+** two comparands contains an escape sequence.
+*/
+static SQLITE_NOINLINE int jsonLabelCompareEscaped(
+  const char *zLeft,          /* The left label */
+  u32 nLeft,                  /* Size of the left label in bytes */
+  int rawLeft,                /* True if zLeft contains no escapes */
+  const char *zRight,         /* The right label */
+  u32 nRight,                 /* Size of the right label in bytes */
+  int rawRight                /* True if zRight is escape-free */
+){
+  u32 cLeft, cRight;
+  assert( rawLeft==0 || rawRight==0 );
+  while( 1 /*exit-by-return*/ ){
+    if( nLeft==0 ){
+      cLeft = 0;
+    }else if( rawLeft || zLeft[0]!='\\' ){
+      cLeft = ((u8*)zLeft)[0];
+      if( cLeft>=0xc0 ){
+        int sz = sqlite3Utf8ReadLimited((u8*)zLeft, nLeft, &cLeft);
+        zLeft += sz;
+        nLeft -= sz;
+      }else{
+        zLeft++;
+        nLeft--;
+      }
+    }else{
+      u32 n = jsonUnescapeOneChar(zLeft, nLeft, &cLeft);
+      zLeft += n;
+      assert( n<=nLeft );
+      nLeft -= n;
+    }
+    if( nRight==0 ){
+      cRight = 0;
+    }else if( rawRight || zRight[0]!='\\' ){
+      cRight = ((u8*)zRight)[0];
+      if( cRight>=0xc0 ){
+        int sz = sqlite3Utf8ReadLimited((u8*)zRight, nRight, &cRight);
+        zRight += sz;
+        nRight -= sz;
+      }else{
+        zRight++;
+        nRight--;
+      }
+    }else{
+      u32 n = jsonUnescapeOneChar(zRight, nRight, &cRight);
+      zRight += n;
+      assert( n<=nRight );
+      nRight -= n;
+    }
+    if( cLeft!=cRight ) return 0;
+    if( cLeft==0 ) return 1;
+  }
+}
+
+/*
+** Compare two object labels.  Return 1 if they are equal and
+** 0 if they differ.  Return -1 if an OOM occurs.
+*/
+static int jsonLabelCompare(
+  const char *zLeft,          /* The left label */
+  u32 nLeft,                  /* Size of the left label in bytes */
+  int rawLeft,                /* True if zLeft contains no escapes */
+  const char *zRight,         /* The right label */
+  u32 nRight,                 /* Size of the right label in bytes */
+  int rawRight                /* True if zRight is escape-free */
+){
+  if( rawLeft && rawRight ){
+    /* Simpliest case:  Neither label contains escapes.  A simple
+    ** memcmp() is sufficient. */
+    if( nLeft!=nRight ) return 0;
+    return memcmp(zLeft, zRight, nLeft)==0;
+  }else{
+    return jsonLabelCompareEscaped(zLeft, nLeft, rawLeft,
+                                   zRight, nRight, rawRight);
+  }
+}
+
+/*
+** Error returns from jsonLookupStep()
+*/
+#define JSON_LOOKUP_ERROR      0xffffffff
+#define JSON_LOOKUP_NOTFOUND   0xfffffffe
+#define JSON_LOOKUP_PATHERROR  0xfffffffd
+#define JSON_LOOKUP_ISERROR(x) ((x)>=JSON_LOOKUP_PATHERROR)
+
+/* Forward declaration */
+static u32 jsonLookupStep(JsonParse*,u32,const char*,u32);
+
+
+/* This helper routine for jsonLookupStep() populates pIns with
+** binary data that is to be inserted into pParse.
+**
+** In the common case, pIns just points to pParse->aIns and pParse->nIns.
+** But if the zPath of the original edit operation includes path elements
+** that go deeper, additional substructure must be created.
+**
+** For example:
+**
+**     json_insert('{}', '$.a.b.c', 123);
+**
+** The search stops at '$.a'  But additional substructure must be
+** created for the ".b.c" part of the patch so that the final result
+** is:  {"a":{"b":{"c"::123}}}.  This routine populates pIns with
+** the binary equivalent of {"b":{"c":123}} so that it can be inserted.
+**
+** The caller is responsible for resetting pIns when it has finished
+** using the substructure.
+*/
+static u32 jsonCreateEditSubstructure(
+  JsonParse *pParse,  /* The original JSONB that is being edited */
+  JsonParse *pIns,    /* Populate this with the blob data to insert */
+  const char *zTail   /* Tail of the path that determins substructure */
+){
+  static const u8 emptyObject[] = { JSONB_ARRAY, JSONB_OBJECT };
+  int rc;
+  memset(pIns, 0, sizeof(*pIns));
+  pIns->db = pParse->db;
+  if( zTail[0]==0 ){
+    /* No substructure.  Just insert what is given in pParse. */
+    pIns->aBlob = pParse->aIns;
+    pIns->nBlob = pParse->nIns;
+    rc = 0;
+  }else{
+    /* Construct the binary substructure */
+    pIns->nBlob = 1;
+    pIns->aBlob = (u8*)&emptyObject[zTail[0]=='.'];
+    pIns->eEdit = pParse->eEdit;
+    pIns->nIns = pParse->nIns;
+    pIns->aIns = pParse->aIns;
+    rc = jsonLookupStep(pIns, 0, zTail, 0);
+    pParse->oom |= pIns->oom;
+  }
+  return rc;  /* Error code only */
+}
+
+/*
+** Search along zPath to find the Json element specified.  Return an
+** index into pParse->aBlob[] for the start of that element's value.
+**
+** If the value found by this routine is the value half of label/value pair
+** within an object, then set pPath->iLabel to the start of the corresponding
+** label, before returning.
+**
+** Return one of the JSON_LOOKUP error codes if problems are seen.
+**
+** This routine will also modify the blob.  If pParse->eEdit is one of
+** JEDIT_DEL, JEDIT_REPL, JEDIT_INS, or JEDIT_SET, then changes might be
+** made to the selected value.  If an edit is performed, then the return
+** value does not necessarily point to the select element.  If an edit
+** is performed, the return value is only useful for detecting error
+** conditions.
+*/
+static u32 jsonLookupStep(
+  JsonParse *pParse,      /* The JSON to search */
+  u32 iRoot,              /* Begin the search at this element of aBlob[] */
+  const char *zPath,      /* The path to search */
+  u32 iLabel              /* Label if iRoot is a value of in an object */
+){
+  u32 i, j, k, nKey, sz, n, iEnd, rc;
+  const char *zKey;
+  u8 x;
+
+  if( zPath[0]==0 ){
+    if( pParse->eEdit && jsonBlobMakeEditable(pParse, pParse->nIns) ){
+      n = jsonbPayloadSize(pParse, iRoot, &sz);
+      sz += n;
+      if( pParse->eEdit==JEDIT_DEL ){
+        if( iLabel>0 ){
+          sz += iRoot - iLabel;
+          iRoot = iLabel;
+        }
+        jsonBlobEdit(pParse, iRoot, sz, 0, 0);
+      }else if( pParse->eEdit==JEDIT_INS ){
+        /* Already exists, so json_insert() is a no-op */
+      }else{
+        /* json_set() or json_replace() */
+        jsonBlobEdit(pParse, iRoot, sz, pParse->aIns, pParse->nIns);
+      }
+    }
+    pParse->iLabel = iLabel;
+    return iRoot;
+  }
+  if( zPath[0]=='.' ){
+    int rawKey = 1;
+    x = pParse->aBlob[iRoot];
+    zPath++;
+    if( zPath[0]=='"' ){
+      zKey = zPath + 1;
+      for(i=1; zPath[i] && zPath[i]!='"'; i++){
+        if( zPath[i]=='\\' && zPath[i+1]!=0 ) i++;
+      }
+      nKey = i-1;
+      if( zPath[i] ){
+        i++;
+      }else{
+        return JSON_LOOKUP_PATHERROR;
+      }
+      testcase( nKey==0 );
+      rawKey = memchr(zKey, '\\', nKey)==0;
+    }else{
+      zKey = zPath;
+      for(i=0; zPath[i] && zPath[i]!='.' && zPath[i]!='['; i++){}
+      nKey = i;
+      if( nKey==0 ){
+        return JSON_LOOKUP_PATHERROR;
+      }
+    }
+    if( (x & 0x0f)!=JSONB_OBJECT ) return JSON_LOOKUP_NOTFOUND;
+    n = jsonbPayloadSize(pParse, iRoot, &sz);
+    j = iRoot + n;  /* j is the index of a label */
+    iEnd = j+sz;
+    while( j<iEnd ){
+      int rawLabel;
+      const char *zLabel;
+      x = pParse->aBlob[j] & 0x0f;
+      if( x<JSONB_TEXT || x>JSONB_TEXTRAW ) return JSON_LOOKUP_ERROR;
+      n = jsonbPayloadSize(pParse, j, &sz);
+      if( n==0 ) return JSON_LOOKUP_ERROR;
+      k = j+n;  /* k is the index of the label text */
+      if( k+sz>=iEnd ) return JSON_LOOKUP_ERROR;
+      zLabel = (const char*)&pParse->aBlob[k];
+      rawLabel = x==JSONB_TEXT || x==JSONB_TEXTRAW;
+      if( jsonLabelCompare(zKey, nKey, rawKey, zLabel, sz, rawLabel) ){
+        u32 v = k+sz;  /* v is the index of the value */
+        if( ((pParse->aBlob[v])&0x0f)>JSONB_OBJECT ) return JSON_LOOKUP_ERROR;
+        n = jsonbPayloadSize(pParse, v, &sz);
+        if( n==0 || v+n+sz>iEnd ) return JSON_LOOKUP_ERROR;
+        assert( j>0 );
+        rc = jsonLookupStep(pParse, v, &zPath[i], j);
+        if( pParse->delta ) jsonAfterEditSizeAdjust(pParse, iRoot);
+        return rc;
+      }
+      j = k+sz;
+      if( ((pParse->aBlob[j])&0x0f)>JSONB_OBJECT ) return JSON_LOOKUP_ERROR;
+      n = jsonbPayloadSize(pParse, j, &sz);
+      if( n==0 ) return JSON_LOOKUP_ERROR;
+      j += n+sz;
+    }
+    if( j>iEnd ) return JSON_LOOKUP_ERROR;
+    if( pParse->eEdit>=JEDIT_INS ){
+      u32 nIns;          /* Total bytes to insert (label+value) */
+      JsonParse v;       /* BLOB encoding of the value to be inserted */
+      JsonParse ix;      /* Header of the label to be inserted */
+      testcase( pParse->eEdit==JEDIT_INS );
+      testcase( pParse->eEdit==JEDIT_SET );
+      memset(&ix, 0, sizeof(ix));
+      ix.db = pParse->db;
+      jsonBlobAppendNode(&ix, rawKey?JSONB_TEXTRAW:JSONB_TEXT5, nKey, 0);
+      pParse->oom |= ix.oom;
+      rc = jsonCreateEditSubstructure(pParse, &v, &zPath[i]);
+      if( !JSON_LOOKUP_ISERROR(rc)
+       && jsonBlobMakeEditable(pParse, ix.nBlob+nKey+v.nBlob)
+      ){
+        assert( !pParse->oom );
+        nIns = ix.nBlob + nKey + v.nBlob;
+        jsonBlobEdit(pParse, j, 0, 0, nIns);
+        if( !pParse->oom ){
+          assert( pParse->aBlob!=0 ); /* Because pParse->oom!=0 */
+          assert( ix.aBlob!=0 );      /* Because pPasre->oom!=0 */
+          memcpy(&pParse->aBlob[j], ix.aBlob, ix.nBlob);
+          k = j + ix.nBlob;
+          memcpy(&pParse->aBlob[k], zKey, nKey);
+          k += nKey;
+          memcpy(&pParse->aBlob[k], v.aBlob, v.nBlob);
+          if( ALWAYS(pParse->delta) ) jsonAfterEditSizeAdjust(pParse, iRoot);
+        }
+      }
+      jsonParseReset(&v);
+      jsonParseReset(&ix);
+      return rc;
+    }
+  }else if( zPath[0]=='[' ){
+    x = pParse->aBlob[iRoot] & 0x0f;
+    if( x!=JSONB_ARRAY )  return JSON_LOOKUP_NOTFOUND;
+    n = jsonbPayloadSize(pParse, iRoot, &sz);
+    k = 0;
+    i = 1;
+    while( sqlite3Isdigit(zPath[i]) ){
+      k = k*10 + zPath[i] - '0';
+      i++;
+    }
+    if( i<2 || zPath[i]!=']' ){
+      if( zPath[1]=='#' ){
+        k = jsonbArrayCount(pParse, iRoot);
+        i = 2;
+        if( zPath[2]=='-' && sqlite3Isdigit(zPath[3]) ){
+          unsigned int nn = 0;
+          i = 3;
+          do{
+            nn = nn*10 + zPath[i] - '0';
+            i++;
+          }while( sqlite3Isdigit(zPath[i]) );
+          if( nn>k ) return JSON_LOOKUP_NOTFOUND;
+          k -= nn;
+        }
+        if( zPath[i]!=']' ){
+          return JSON_LOOKUP_PATHERROR;
+        }
+      }else{
+        return JSON_LOOKUP_PATHERROR;
+      }
+    }
+    j = iRoot+n;
+    iEnd = j+sz;
+    while( j<iEnd ){
+      if( k==0 ){
+        rc = jsonLookupStep(pParse, j, &zPath[i+1], 0);
+        if( pParse->delta ) jsonAfterEditSizeAdjust(pParse, iRoot);
+        return rc;
+      }
+      k--;
+      n = jsonbPayloadSize(pParse, j, &sz);
+      if( n==0 ) return JSON_LOOKUP_ERROR;
+      j += n+sz;
+    }
+    if( j>iEnd ) return JSON_LOOKUP_ERROR;
+    if( k>0 ) return JSON_LOOKUP_NOTFOUND;
+    if( pParse->eEdit>=JEDIT_INS ){
+      JsonParse v;
+      testcase( pParse->eEdit==JEDIT_INS );
+      testcase( pParse->eEdit==JEDIT_SET );
+      rc = jsonCreateEditSubstructure(pParse, &v, &zPath[i+1]);
+      if( !JSON_LOOKUP_ISERROR(rc)
+       && jsonBlobMakeEditable(pParse, v.nBlob)
+      ){
+        assert( !pParse->oom );
+        jsonBlobEdit(pParse, j, 0, v.aBlob, v.nBlob);
+      }
+      jsonParseReset(&v);
+      if( pParse->delta ) jsonAfterEditSizeAdjust(pParse, iRoot);
+      return rc;
+    }
+  }else{
+    return JSON_LOOKUP_PATHERROR;
+  }
+  return JSON_LOOKUP_NOTFOUND;
+}
+
+/*
+** Convert a JSON BLOB into text and make that text the return value
+** of an SQL function.
+*/
+static void jsonReturnTextJsonFromBlob(
+  sqlite3_context *ctx,
+  const u8 *aBlob,
+  u32 nBlob
+){
+  JsonParse x;
+  JsonString s;
+
+  if( NEVER(aBlob==0) ) return;
+  memset(&x, 0, sizeof(x));
+  x.aBlob = (u8*)aBlob;
+  x.nBlob = nBlob;
+  jsonStringInit(&s, ctx);
+  jsonTranslateBlobToText(&x, 0, &s);
+  jsonReturnString(&s, 0, 0);
+}
+
+
+/*
+** Return the value of the BLOB node at index i.
+**
+** If the value is a primitive, return it as an SQL value.
+** If the value is an array or object, return it as either
+** JSON text or the BLOB encoding, depending on the JSON_B flag
+** on the userdata.
+*/
+static void jsonReturnFromBlob(
+  JsonParse *pParse,          /* Complete JSON parse tree */
+  u32 i,                      /* Index of the node */
+  sqlite3_context *pCtx,      /* Return value for this function */
+  int textOnly                /* return text JSON.  Disregard user-data */
+){
+  u32 n, sz;
+  int rc;
+  sqlite3 *db = sqlite3_context_db_handle(pCtx);
+
+  n = jsonbPayloadSize(pParse, i, &sz);
+  if( n==0 ){
+    sqlite3_result_error(pCtx, "malformed JSON", -1);
+    return;
+  }
+  switch( pParse->aBlob[i] & 0x0f ){
+    case JSONB_NULL: {
+      if( sz ) goto returnfromblob_malformed;
+      sqlite3_result_null(pCtx);
+      break;
+    }
+    case JSONB_TRUE: {
+      if( sz ) goto returnfromblob_malformed;
+      sqlite3_result_int(pCtx, 1);
+      break;
+    }
+    case JSONB_FALSE: {
+      if( sz ) goto returnfromblob_malformed;
+      sqlite3_result_int(pCtx, 0);
+      break;
+    }
+    case JSONB_INT5:
+    case JSONB_INT: {
+      sqlite3_int64 iRes = 0;
+      char *z;
+      int bNeg = 0;
+      char x;
+      if( sz==0 ) goto returnfromblob_malformed;
+      x = (char)pParse->aBlob[i+n];
+      if( x=='-' ){
+        if( sz<2 ) goto returnfromblob_malformed;
+        n++;
+        sz--;
+        bNeg = 1;
+      }
+      z = sqlite3DbStrNDup(db, (const char*)&pParse->aBlob[i+n], (int)sz);
+      if( z==0 ) goto returnfromblob_oom;
+      rc = sqlite3DecOrHexToI64(z, &iRes);
+      sqlite3DbFree(db, z);
+      if( rc==0 ){
+        sqlite3_result_int64(pCtx, bNeg ? -iRes : iRes);
+      }else if( rc==3 && bNeg ){
+        sqlite3_result_int64(pCtx, SMALLEST_INT64);
+      }else if( rc==1 ){
+        goto returnfromblob_malformed;
+      }else{
+        if( bNeg ){ n--; sz++; }
+        goto to_double;
+      }
+      break;
+    }
+    case JSONB_FLOAT5:
+    case JSONB_FLOAT: {
+      double r;
+      char *z;
+      if( sz==0 ) goto returnfromblob_malformed;
+    to_double:
+      z = sqlite3DbStrNDup(db, (const char*)&pParse->aBlob[i+n], (int)sz);
+      if( z==0 ) goto returnfromblob_oom;
+      rc = sqlite3AtoF(z, &r, sqlite3Strlen30(z), SQLITE_UTF8);
+      sqlite3DbFree(db, z);
+      if( rc<=0 ) goto returnfromblob_malformed;
+      sqlite3_result_double(pCtx, r);
+      break;
+    }
+    case JSONB_TEXTRAW:
+    case JSONB_TEXT: {
+      sqlite3_result_text(pCtx, (char*)&pParse->aBlob[i+n], sz,
+                          SQLITE_TRANSIENT);
+      break;
+    }
+    case JSONB_TEXT5:
+    case JSONB_TEXTJ: {
+      /* Translate JSON formatted string into raw text */
+      u32 iIn, iOut;
+      const char *z;
+      char *zOut;
+      u32 nOut = sz;
+      z = (const char*)&pParse->aBlob[i+n];
+      zOut = sqlite3DbMallocRaw(db, nOut+1);
+      if( zOut==0 ) goto returnfromblob_oom;
+      for(iIn=iOut=0; iIn<sz; iIn++){
+        char c = z[iIn];
+        if( c=='\\' ){
+          u32 v;
+          u32 szEscape = jsonUnescapeOneChar(&z[iIn], sz-iIn, &v);
+          if( v<=0x7f ){
+            zOut[iOut++] = (char)v;
+          }else if( v<=0x7ff ){
+            assert( szEscape>=2 );
+            zOut[iOut++] = (char)(0xc0 | (v>>6));
+            zOut[iOut++] = 0x80 | (v&0x3f);
+          }else if( v<0x10000 ){
+            assert( szEscape>=3 );
+            zOut[iOut++] = 0xe0 | (v>>12);
+            zOut[iOut++] = 0x80 | ((v>>6)&0x3f);
+            zOut[iOut++] = 0x80 | (v&0x3f);
+          }else if( v==JSON_INVALID_CHAR ){
+            /* Silently ignore illegal unicode */
+          }else{
+            assert( szEscape>=4 );
+            zOut[iOut++] = 0xf0 | (v>>18);
+            zOut[iOut++] = 0x80 | ((v>>12)&0x3f);
+            zOut[iOut++] = 0x80 | ((v>>6)&0x3f);
+            zOut[iOut++] = 0x80 | (v&0x3f);
+          }
+          iIn += szEscape - 1;
+        }else{
+          zOut[iOut++] = c;
+        }
+      } /* end for() */
+      assert( iOut<=nOut );
+      zOut[iOut] = 0;
+      sqlite3_result_text(pCtx, zOut, iOut, SQLITE_DYNAMIC);
+      break;
+    }
+    case JSONB_ARRAY:
+    case JSONB_OBJECT: {
+      int flags = textOnly ? 0 : SQLITE_PTR_TO_INT(sqlite3_user_data(pCtx));
+      if( flags & JSON_BLOB ){
+        sqlite3_result_blob(pCtx, &pParse->aBlob[i], sz+n, SQLITE_TRANSIENT);
+      }else{
+        jsonReturnTextJsonFromBlob(pCtx, &pParse->aBlob[i], sz+n);
+      }
+      break;
+    }
+    default: {
+      goto returnfromblob_malformed;
+    }
+  }
+  return;
+
+returnfromblob_oom:
+  sqlite3_result_error_nomem(pCtx);
+  return;
+
+returnfromblob_malformed:
+  sqlite3_result_error(pCtx, "malformed JSON", -1);
+  return;
+}
+
+/*
+** pArg is a function argument that might be an SQL value or a JSON
+** value.  Figure out what it is and encode it as a JSONB blob.
+** Return the results in pParse.
+**
+** pParse is uninitialized upon entry.  This routine will handle the
+** initialization of pParse.  The result will be contained in
+** pParse->aBlob and pParse->nBlob.  pParse->aBlob might be dynamically
+** allocated (if pParse->nBlobAlloc is greater than zero) in which case
+** the caller is responsible for freeing the space allocated to pParse->aBlob
+** when it has finished with it.  Or pParse->aBlob might be a static string
+** or a value obtained from sqlite3_value_blob(pArg).
+**
+** If the argument is a BLOB that is clearly not a JSONB, then this
+** function might set an error message in ctx and return non-zero.
+** It might also set an error message and return non-zero on an OOM error.
+*/
+static int jsonFunctionArgToBlob(
+  sqlite3_context *ctx,
+  sqlite3_value *pArg,
+  JsonParse *pParse
+){
+  int eType = sqlite3_value_type(pArg);
+  static u8 aNull[] = { 0x00 };
+  memset(pParse, 0, sizeof(pParse[0]));
+  pParse->db = sqlite3_context_db_handle(ctx);
+  switch( eType ){
+    default: {
+      pParse->aBlob = aNull;
+      pParse->nBlob = 1;
+      return 0;
+    }
+    case SQLITE_BLOB: {
+      if( jsonFuncArgMightBeBinary(pArg) ){
+        pParse->aBlob = (u8*)sqlite3_value_blob(pArg);
+        pParse->nBlob = sqlite3_value_bytes(pArg);
+      }else{
+        sqlite3_result_error(ctx, "JSON cannot hold BLOB values", -1);
+        return 1;
+      }
+      break;
+    }
+    case SQLITE_TEXT: {
+      const char *zJson = (const char*)sqlite3_value_text(pArg);
+      int nJson = sqlite3_value_bytes(pArg);
+      if( zJson==0 ) return 1;
+      if( sqlite3_value_subtype(pArg)==JSON_SUBTYPE ){
+        pParse->zJson = (char*)zJson;
+        pParse->nJson = nJson;
+        if( jsonConvertTextToBlob(pParse, ctx) ){
+          sqlite3_result_error(ctx, "malformed JSON", -1);
+          sqlite3DbFree(pParse->db, pParse->aBlob);
+          memset(pParse, 0, sizeof(pParse[0]));
+          return 1;
+        }
+      }else{
+        jsonBlobAppendNode(pParse, JSONB_TEXTRAW, nJson, zJson);
+      }
+      break;
+    }
+    case SQLITE_FLOAT: {
+      double r = sqlite3_value_double(pArg);
+      if( NEVER(sqlite3IsNaN(r)) ){
+        jsonBlobAppendNode(pParse, JSONB_NULL, 0, 0);
+      }else{
+        int n = sqlite3_value_bytes(pArg);
+        const char *z = (const char*)sqlite3_value_text(pArg);
+        if( z==0 ) return 1;
+        if( z[0]=='I' ){
+          jsonBlobAppendNode(pParse, JSONB_FLOAT, 5, "9e999");
+        }else if( z[0]=='-' && z[1]=='I' ){
+          jsonBlobAppendNode(pParse, JSONB_FLOAT, 6, "-9e999");
+        }else{
+          jsonBlobAppendNode(pParse, JSONB_FLOAT, n, z);
+        }
+      }
+      break;
+    }
+    case SQLITE_INTEGER: {
+      int n = sqlite3_value_bytes(pArg);
+      const char *z = (const char*)sqlite3_value_text(pArg);
+      if( z==0 ) return 1;
+      jsonBlobAppendNode(pParse, JSONB_INT, n, z);
+      break;
+    }
+  }
+  if( pParse->oom ){
+    sqlite3_result_error_nomem(ctx);
+    return 1;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Generate a bad path error.
+**
+** If ctx is not NULL then push the error message into ctx and return NULL.
+** If ctx is NULL, then return the text of the error message.
+*/
+static char *jsonBadPathError(
+  sqlite3_context *ctx,     /* The function call containing the error */
+  const char *zPath         /* The path with the problem */
+){
+  char *zMsg = sqlite3_mprintf("bad JSON path: %Q", zPath);
+  if( ctx==0 ) return zMsg;
+  if( zMsg ){
+    sqlite3_result_error(ctx, zMsg, -1);
+    sqlite3_free(zMsg);
+  }else{
+    sqlite3_result_error_nomem(ctx);
+  }
+  return 0;
+}
+
+/* argv[0] is a BLOB that seems likely to be a JSONB.  Subsequent
+** arguments come in parse where each pair contains a JSON path and
+** content to insert or set at that patch.  Do the updates
+** and return the result.
+**
+** The specific operation is determined by eEdit, which can be one
+** of JEDIT_INS, JEDIT_REPL, or JEDIT_SET.
+*/
+static void jsonInsertIntoBlob(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv,
+  int eEdit                /* JEDIT_INS, JEDIT_REPL, or JEDIT_SET */
+){
+  int i;
+  u32 rc = 0;
+  const char *zPath = 0;
+  int flgs;
+  JsonParse *p;
+  JsonParse ax;
+
+  assert( (argc&1)==1 );
+  flgs = argc==1 ? 0 : JSON_EDITABLE;
+  p = jsonParseFuncArg(ctx, argv[0], flgs);
+  if( p==0 ) return;
+  for(i=1; i<argc-1; i+=2){
+    if( sqlite3_value_type(argv[i])==SQLITE_NULL ) continue;
+    zPath = (const char*)sqlite3_value_text(argv[i]);
+    if( zPath==0 ){
+      sqlite3_result_error_nomem(ctx);
+      jsonParseFree(p);
+      return;
+    }
+    if( zPath[0]!='$' ) goto jsonInsertIntoBlob_patherror;
+    if( jsonFunctionArgToBlob(ctx, argv[i+1], &ax) ){
+      jsonParseReset(&ax);
+      jsonParseFree(p);
+      return;
+    }
+    if( zPath[1]==0 ){
+      if( eEdit==JEDIT_REPL || eEdit==JEDIT_SET ){
+        jsonBlobEdit(p, 0, p->nBlob, ax.aBlob, ax.nBlob);
+      }
+      rc = 0;
+   }else{
+      p->eEdit = eEdit;
+      p->nIns = ax.nBlob;
+      p->aIns = ax.aBlob;
+      p->delta = 0;
+      rc = jsonLookupStep(p, 0, zPath+1, 0);
+    }
+    jsonParseReset(&ax);
+    if( rc==JSON_LOOKUP_NOTFOUND ) continue;
+    if( JSON_LOOKUP_ISERROR(rc) ) goto jsonInsertIntoBlob_patherror;
+  }
+  jsonReturnParse(ctx, p);
+  jsonParseFree(p);
+  return;
+
+jsonInsertIntoBlob_patherror:
+  jsonParseFree(p);
+  if( rc==JSON_LOOKUP_ERROR ){
+    sqlite3_result_error(ctx, "malformed JSON", -1);
+  }else{
+    jsonBadPathError(ctx, zPath);
+  }
+  return;
+}
+
+/*
+** If pArg is a blob that seems like a JSONB blob, then initialize
+** p to point to that JSONB and return TRUE.  If pArg does not seem like
+** a JSONB blob, then return FALSE;
+**
+** This routine is only called if it is already known that pArg is a
+** blob.  The only open question is whether or not the blob appears
+** to be a JSONB blob.
+*/
+static int jsonArgIsJsonb(sqlite3_value *pArg, JsonParse *p){
+  u32 n, sz = 0;
+  p->aBlob = (u8*)sqlite3_value_blob(pArg);
+  p->nBlob = (u32)sqlite3_value_bytes(pArg);
+  if( p->nBlob==0 ){
+    p->aBlob = 0;
+    return 0;
+  }
+  if( NEVER(p->aBlob==0) ){
+    return 0;
+  }
+  if( (p->aBlob[0] & 0x0f)<=JSONB_OBJECT
+   && (n = jsonbPayloadSize(p, 0, &sz))>0
+   && sz+n==p->nBlob
+   && ((p->aBlob[0] & 0x0f)>JSONB_FALSE || sz==0)
+  ){
+    return 1;
+  }
+  p->aBlob = 0;
+  p->nBlob = 0;
+  return 0;
+}
+
+/*
+** Generate a JsonParse object, containing valid JSONB in aBlob and nBlob,
+** from the SQL function argument pArg.  Return a pointer to the new
+** JsonParse object.
+**
+** Ownership of the new JsonParse object is passed to the caller.  The
+** caller should invoke jsonParseFree() on the return value when it
+** has finished using it.
+**
+** If any errors are detected, an appropriate error messages is set
+** using sqlite3_result_error() or the equivalent and this routine
+** returns NULL.  This routine also returns NULL if the pArg argument
+** is an SQL NULL value, but no error message is set in that case.  This
+** is so that SQL functions that are given NULL arguments will return
+** a NULL value.
+*/
+static JsonParse *jsonParseFuncArg(
+  sqlite3_context *ctx,
+  sqlite3_value *pArg,
+  u32 flgs
+){
+  int eType;                   /* Datatype of pArg */
+  JsonParse *p = 0;            /* Value to be returned */
+  JsonParse *pFromCache = 0;   /* Value taken from cache */
+  sqlite3 *db;                 /* The database connection */
+
+  assert( ctx!=0 );
+  eType = sqlite3_value_type(pArg);
+  if( eType==SQLITE_NULL ){
+    return 0;
+  }
+  pFromCache = jsonCacheSearch(ctx, pArg);
+  if( pFromCache ){
+    pFromCache->nJPRef++;
+    if( (flgs & JSON_EDITABLE)==0 ){
+      return pFromCache;
+    }
+  }
+  db = sqlite3_context_db_handle(ctx);
+rebuild_from_cache:
+  p = sqlite3DbMallocZero(db, sizeof(*p));
+  if( p==0 ) goto json_pfa_oom;
+  memset(p, 0, sizeof(*p));
+  p->db = db;
+  p->nJPRef = 1;
+  if( pFromCache!=0 ){
+    u32 nBlob = pFromCache->nBlob;
+    p->aBlob = sqlite3DbMallocRaw(db, nBlob);
+    if( p->aBlob==0 ) goto json_pfa_oom;
+    memcpy(p->aBlob, pFromCache->aBlob, nBlob);
+    p->nBlobAlloc = p->nBlob = nBlob;
+    p->hasNonstd = pFromCache->hasNonstd;
+    jsonParseFree(pFromCache);
+    return p;
+  }
+  if( eType==SQLITE_BLOB ){
+    if( jsonArgIsJsonb(pArg,p) ){
+      if( (flgs & JSON_EDITABLE)!=0 && jsonBlobMakeEditable(p, 0)==0 ){
+        goto json_pfa_oom;
+      }
+      return p;
+    }
+    /* If the blob is not valid JSONB, fall through into trying to cast
+    ** the blob into text which is then interpreted as JSON.  (tag-20240123-a)
+    **
+    ** This goes against all historical documentation about how the SQLite
+    ** JSON functions were suppose to work.  From the beginning, blob was
+    ** reserved for expansion and a blob value should have raised an error.
+    ** But it did not, due to a bug.  And many applications came to depend
+    ** upon this buggy behavior, espeically when using the CLI and reading
+    ** JSON text using readfile(), which returns a blob.  For this reason
+    ** we will continue to support the bug moving forward.
+    ** See for example https://sqlite.org/forum/forumpost/012136abd5292b8d
+    */
+  }
+  p->zJson = (char*)sqlite3_value_text(pArg);
+  p->nJson = sqlite3_value_bytes(pArg);
+  if( db->mallocFailed ) goto json_pfa_oom;
+  if( p->nJson==0 ) goto json_pfa_malformed;
+  assert( p->zJson!=0 );
+  if( jsonConvertTextToBlob(p, (flgs & JSON_KEEPERROR) ? 0 : ctx) ){
+    if( flgs & JSON_KEEPERROR ){
+      p->nErr = 1;
+      return p;
+    }else{
+      jsonParseFree(p);
+      return 0;
+    }
+  }else{
+    int isRCStr = sqlite3ValueIsOfClass(pArg, sqlite3RCStrUnref);
+    int rc;
+    if( !isRCStr ){
+      char *zNew = sqlite3RCStrNew( p->nJson );
+      if( zNew==0 ) goto json_pfa_oom;
+      memcpy(zNew, p->zJson, p->nJson);
+      p->zJson = zNew;
+      p->zJson[p->nJson] = 0;
+    }else{
+      sqlite3RCStrRef(p->zJson);
+    }
+    p->bJsonIsRCStr = 1;
+    rc = jsonCacheInsert(ctx, p);
+    if( rc==SQLITE_NOMEM ) goto json_pfa_oom;
+    if( flgs & JSON_EDITABLE ){
+      pFromCache = p;
+      p = 0;
+      goto rebuild_from_cache;
+    }
+  }
+  return p;
+
+json_pfa_malformed:
+  if( flgs & JSON_KEEPERROR ){
+    p->nErr = 1;
+    return p;
+  }else{
+    jsonParseFree(p);
+    sqlite3_result_error(ctx, "malformed JSON", -1);
+    return 0;
+  }
+
+json_pfa_oom:
+  jsonParseFree(pFromCache);
+  jsonParseFree(p);
+  sqlite3_result_error_nomem(ctx);
+  return 0;
+}
+
+/*
+** Make the return value of a JSON function either the raw JSONB blob
+** or make it JSON text, depending on whether the JSON_BLOB flag is
+** set on the function.
+*/
+static void jsonReturnParse(
+  sqlite3_context *ctx,
+  JsonParse *p
+){
+  int flgs;
+  if( p->oom ){
+    sqlite3_result_error_nomem(ctx);
+    return;
+  }
+  flgs = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+  if( flgs & JSON_BLOB ){
+    if( p->nBlobAlloc>0 && !p->bReadOnly ){
+      sqlite3_result_blob(ctx, p->aBlob, p->nBlob, SQLITE_DYNAMIC);
+      p->nBlobAlloc = 0;
+    }else{
+      sqlite3_result_blob(ctx, p->aBlob, p->nBlob, SQLITE_TRANSIENT);
+    }
+  }else{
+    JsonString s;
+    jsonStringInit(&s, ctx);
+    p->delta = 0;
+    jsonTranslateBlobToText(p, 0, &s);
+    jsonReturnString(&s, p, ctx);
+    sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+  }
+}
+
+/****************************************************************************
+** SQL functions used for testing and debugging
+****************************************************************************/
+
+#if SQLITE_DEBUG
+/*
+** Decode JSONB bytes in aBlob[] starting at iStart through but not
+** including iEnd.  Indent the
+** content by nIndent spaces.
+*/
+static void jsonDebugPrintBlob(
+  JsonParse *pParse, /* JSON content */
+  u32 iStart,        /* Start rendering here */
+  u32 iEnd,          /* Do not render this byte or any byte after this one */
+  int nIndent,       /* Indent by this many spaces */
+  sqlite3_str *pOut  /* Generate output into this sqlite3_str object */
+){
+  while( iStart<iEnd ){
+    u32 i, n, nn, sz = 0;
+    int showContent = 1;
+    u8 x = pParse->aBlob[iStart] & 0x0f;
+    u32 savedNBlob = pParse->nBlob;
+    sqlite3_str_appendf(pOut, "%5d:%*s", iStart, nIndent, "");
+    if( pParse->nBlobAlloc>pParse->nBlob ){
+      pParse->nBlob = pParse->nBlobAlloc;
+    }
+    nn = n = jsonbPayloadSize(pParse, iStart, &sz);
+    if( nn==0 ) nn = 1;
+    if( sz>0 && x<JSONB_ARRAY ){
+      nn += sz;
+    }
+    for(i=0; i<nn; i++){
+      sqlite3_str_appendf(pOut, " %02x", pParse->aBlob[iStart+i]);
+    }
+    if( n==0 ){
+      sqlite3_str_appendf(pOut, "   ERROR invalid node size\n");
+      iStart = n==0 ? iStart+1 : iEnd;
+      continue;
+    }
+    pParse->nBlob = savedNBlob;
+    if( iStart+n+sz>iEnd ){
+      iEnd = iStart+n+sz;
+      if( iEnd>pParse->nBlob ){
+        if( pParse->nBlobAlloc>0 && iEnd>pParse->nBlobAlloc ){
+          iEnd = pParse->nBlobAlloc;
+        }else{
+          iEnd = pParse->nBlob;
+        }
+      }
+    }
+    sqlite3_str_appendall(pOut,"  <-- ");
+    switch( x ){
+      case JSONB_NULL:     sqlite3_str_appendall(pOut,"null"); break;
+      case JSONB_TRUE:     sqlite3_str_appendall(pOut,"true"); break;
+      case JSONB_FALSE:    sqlite3_str_appendall(pOut,"false"); break;
+      case JSONB_INT:      sqlite3_str_appendall(pOut,"int"); break;
+      case JSONB_INT5:     sqlite3_str_appendall(pOut,"int5"); break;
+      case JSONB_FLOAT:    sqlite3_str_appendall(pOut,"float"); break;
+      case JSONB_FLOAT5:   sqlite3_str_appendall(pOut,"float5"); break;
+      case JSONB_TEXT:     sqlite3_str_appendall(pOut,"text"); break;
+      case JSONB_TEXTJ:    sqlite3_str_appendall(pOut,"textj"); break;
+      case JSONB_TEXT5:    sqlite3_str_appendall(pOut,"text5"); break;
+      case JSONB_TEXTRAW:  sqlite3_str_appendall(pOut,"textraw"); break;
+      case JSONB_ARRAY: {
+        sqlite3_str_appendf(pOut,"array, %u bytes\n", sz);
+        jsonDebugPrintBlob(pParse, iStart+n, iStart+n+sz, nIndent+2, pOut);
+        showContent = 0;
+        break;
+      }
+      case JSONB_OBJECT: {
+        sqlite3_str_appendf(pOut, "object, %u bytes\n", sz);
+        jsonDebugPrintBlob(pParse, iStart+n, iStart+n+sz, nIndent+2, pOut);
+        showContent = 0;
+        break;
+      }
+      default: {
+        sqlite3_str_appendall(pOut, "ERROR: unknown node type\n");
+        showContent = 0;
+        break;
+      }
+    }
+    if( showContent ){
+      if( sz==0 && x<=JSONB_FALSE ){
+        sqlite3_str_append(pOut, "\n", 1);
+      }else{
+        u32 j;
+        sqlite3_str_appendall(pOut, ": \"");
+        for(j=iStart+n; j<iStart+n+sz; j++){
+          u8 c = pParse->aBlob[j];
+          if( c<0x20 || c>=0x7f ) c = '.';
+          sqlite3_str_append(pOut, (char*)&c, 1);
+        }
+        sqlite3_str_append(pOut, "\"\n", 2);
+      }
+    }
+    iStart += n + sz;
+  }
+}
+static void jsonShowParse(JsonParse *pParse){
+  sqlite3_str out;
+  char zBuf[1000];
+  if( pParse==0 ){
+    printf("NULL pointer\n");
+    return;
+  }else{
+    printf("nBlobAlloc = %u\n", pParse->nBlobAlloc);
+    printf("nBlob = %u\n", pParse->nBlob);
+    printf("delta = %d\n", pParse->delta);
+    if( pParse->nBlob==0 ) return;
+    printf("content (bytes 0..%u):\n", pParse->nBlob-1);
+  }
+  sqlite3StrAccumInit(&out, 0, zBuf, sizeof(zBuf), 1000000);
+  jsonDebugPrintBlob(pParse, 0, pParse->nBlob, 0, &out);
+  printf("%s", sqlite3_str_value(&out));
+  sqlite3_str_reset(&out);
+}
+#endif /* SQLITE_DEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+** SQL function:   json_parse(JSON)
+**
+** Parse JSON using jsonParseFuncArg().  Return text that is a
+** human-readable dump of the binary JSONB for the input parameter.
+*/
+static void jsonParseFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;        /* The parse */
+  sqlite3_str out;
+
+  assert( argc>=1 );
+  sqlite3StrAccumInit(&out, 0, 0, 0, 1000000);
+  p = jsonParseFuncArg(ctx, argv[0], 0);
+  if( p==0 ) return;
+  if( argc==1 ){
+    jsonDebugPrintBlob(p, 0, p->nBlob, 0, &out);
+    sqlite3_result_text64(ctx,out.zText,out.nChar,SQLITE_TRANSIENT,SQLITE_UTF8);
+  }else{
+    jsonShowParse(p);
+  }
+  jsonParseFree(p);
+  sqlite3_str_reset(&out);
+}
+#endif /* SQLITE_DEBUG */
+
+/****************************************************************************
+** Scalar SQL function implementations
+****************************************************************************/
+
+/*
+** Implementation of the json_quote(VALUE) function.  Return a JSON value
+** corresponding to the SQL value input.  Mostly this means putting
+** double-quotes around strings and returning the unquoted string "null"
+** when given a NULL input.
+*/
+static void jsonQuoteFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonString jx;
+  UNUSED_PARAMETER(argc);
+
+  jsonStringInit(&jx, ctx);
+  jsonAppendSqlValue(&jx, argv[0]);
+  jsonReturnString(&jx, 0, 0);
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+
+/*
+** Implementation of the json_array(VALUE,...) function.  Return a JSON
+** array that contains all values given in arguments.  Or if any argument
+** is a BLOB, throw an error.
+*/
+static void jsonArrayFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+  JsonString jx;
+
+  jsonStringInit(&jx, ctx);
+  jsonAppendChar(&jx, '[');
+  for(i=0; i<argc; i++){
+    jsonAppendSeparator(&jx);
+    jsonAppendSqlValue(&jx, argv[i]);
+  }
+  jsonAppendChar(&jx, ']');
+  jsonReturnString(&jx, 0, 0);
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+
+/*
+** json_array_length(JSON)
+** json_array_length(JSON, PATH)
+**
+** Return the number of elements in the top-level JSON array.
+** Return 0 if the input is not a well-formed JSON array.
+*/
+static void jsonArrayLengthFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;          /* The parse */
+  sqlite3_int64 cnt = 0;
+  u32 i;
+  u8 eErr = 0;
+
+  p = jsonParseFuncArg(ctx, argv[0], 0);
+  if( p==0 ) return;
+  if( argc==2 ){
+    const char *zPath = (const char*)sqlite3_value_text(argv[1]);
+    if( zPath==0 ){
+      jsonParseFree(p);
+      return;
+    }
+    i = jsonLookupStep(p, 0, zPath[0]=='$' ? zPath+1 : "@", 0);
+    if( JSON_LOOKUP_ISERROR(i) ){
+      if( i==JSON_LOOKUP_NOTFOUND ){
+        /* no-op */
+      }else if( i==JSON_LOOKUP_PATHERROR ){
+        jsonBadPathError(ctx, zPath);
+      }else{
+        sqlite3_result_error(ctx, "malformed JSON", -1);
+      }
+      eErr = 1;
+      i = 0;
+    }
+  }else{
+    i = 0;
+  }
+  if( (p->aBlob[i] & 0x0f)==JSONB_ARRAY ){
+    cnt = jsonbArrayCount(p, i);
+  }
+  if( !eErr ) sqlite3_result_int64(ctx, cnt);
+  jsonParseFree(p);
+}
+
+/* True if the string is all alphanumerics and underscores */
+static int jsonAllAlphanum(const char *z, int n){
+  int i;
+  for(i=0; i<n && (sqlite3Isalnum(z[i]) || z[i]=='_'); i++){}
+  return i==n;
+}
+
+/*
+** json_extract(JSON, PATH, ...)
+** "->"(JSON,PATH)
+** "->>"(JSON,PATH)
+**
+** Return the element described by PATH.  Return NULL if that PATH element
+** is not found.
+**
+** If JSON_JSON is set or if more that one PATH argument is supplied then
+** always return a JSON representation of the result.  If JSON_SQL is set,
+** then always return an SQL representation of the result.  If neither flag
+** is present and argc==2, then return JSON for objects and arrays and SQL
+** for all other values.
+**
+** When multiple PATH arguments are supplied, the result is a JSON array
+** containing the result of each PATH.
+**
+** Abbreviated JSON path expressions are allows if JSON_ABPATH, for
+** compatibility with PG.
+*/
+static void jsonExtractFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p = 0;      /* The parse */
+  int flags;             /* Flags associated with the function */
+  int i;                 /* Loop counter */
+  JsonString jx;         /* String for array result */
+
+  if( argc<2 ) return;
+  p = jsonParseFuncArg(ctx, argv[0], 0);
+  if( p==0 ) return;
+  flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+  jsonStringInit(&jx, ctx);
+  if( argc>2 ){
+    jsonAppendChar(&jx, '[');
+  }
+  for(i=1; i<argc; i++){
+    /* With a single PATH argument */
+    const char *zPath = (const char*)sqlite3_value_text(argv[i]);
+    int nPath;
+    u32 j;
+    if( zPath==0 ) goto json_extract_error;
+    nPath = sqlite3Strlen30(zPath);
+    if( zPath[0]=='$' ){
+      j = jsonLookupStep(p, 0, zPath+1, 0);
+    }else if( (flags & JSON_ABPATH) ){
+      /* The -> and ->> operators accept abbreviated PATH arguments.  This
+      ** is mostly for compatibility with PostgreSQL, but also for
+      ** convenience.
+      **
+      **     NUMBER   ==>  $[NUMBER]     // PG compatible
+      **     LABEL    ==>  $.LABEL       // PG compatible
+      **     [NUMBER] ==>  $[NUMBER]     // Not PG.  Purely for convenience
+      **
+      ** Updated 2024-05-27:  If the NUMBER is negative, then PG counts from
+      ** the right of the array.  Hence for negative NUMBER:
+      **
+      **     NUMBER   ==>  $[#NUMBER]    // PG compatible
+      */
+      jsonStringInit(&jx, ctx);
+      if( sqlite3_value_type(argv[i])==SQLITE_INTEGER ){
+        jsonAppendRawNZ(&jx, "[", 1);
+        if( zPath[0]=='-' ) jsonAppendRawNZ(&jx,"#",1);
+        jsonAppendRaw(&jx, zPath, nPath);
+        jsonAppendRawNZ(&jx, "]", 2);
+      }else if( jsonAllAlphanum(zPath, nPath) ){
+        jsonAppendRawNZ(&jx, ".", 1);
+        jsonAppendRaw(&jx, zPath, nPath);
+      }else if( zPath[0]=='[' && nPath>=3 && zPath[nPath-1]==']' ){
+        jsonAppendRaw(&jx, zPath, nPath);
+      }else{
+        jsonAppendRawNZ(&jx, ".\"", 2);
+        jsonAppendRaw(&jx, zPath, nPath);
+        jsonAppendRawNZ(&jx, "\"", 1);
+      }
+      jsonStringTerminate(&jx);
+      j = jsonLookupStep(p, 0, jx.zBuf, 0);
+      jsonStringReset(&jx);
+    }else{
+      jsonBadPathError(ctx, zPath);
+      goto json_extract_error;
+    }
+    if( j<p->nBlob ){
+      if( argc==2 ){
+        if( flags & JSON_JSON ){
+          jsonStringInit(&jx, ctx);
+          jsonTranslateBlobToText(p, j, &jx);
+          jsonReturnString(&jx, 0, 0);
+          jsonStringReset(&jx);
+          assert( (flags & JSON_BLOB)==0 );
+          sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+        }else{
+          jsonReturnFromBlob(p, j, ctx, 0);
+          if( (flags & (JSON_SQL|JSON_BLOB))==0
+           && (p->aBlob[j]&0x0f)>=JSONB_ARRAY
+          ){
+            sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+          }
+        }
+      }else{
+        jsonAppendSeparator(&jx);
+        jsonTranslateBlobToText(p, j, &jx);
+      }
+    }else if( j==JSON_LOOKUP_NOTFOUND ){
+      if( argc==2 ){
+        goto json_extract_error;  /* Return NULL if not found */
+      }else{
+        jsonAppendSeparator(&jx);
+        jsonAppendRawNZ(&jx, "null", 4);
+      }
+    }else if( j==JSON_LOOKUP_ERROR ){
+      sqlite3_result_error(ctx, "malformed JSON", -1);
+      goto json_extract_error;
+    }else{
+      jsonBadPathError(ctx, zPath);
+      goto json_extract_error;
+    }
+  }
+  if( argc>2 ){
+    jsonAppendChar(&jx, ']');
+    jsonReturnString(&jx, 0, 0);
+    if( (flags & JSON_BLOB)==0 ){
+      sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+    }
+  }
+json_extract_error:
+  jsonStringReset(&jx);
+  jsonParseFree(p);
+  return;
+}
+
+/*
+** Return codes for jsonMergePatch()
+*/
+#define JSON_MERGE_OK          0     /* Success */
+#define JSON_MERGE_BADTARGET   1     /* Malformed TARGET blob */
+#define JSON_MERGE_BADPATCH    2     /* Malformed PATCH blob */
+#define JSON_MERGE_OOM         3     /* Out-of-memory condition */
+
+/*
+** RFC-7396 MergePatch for two JSONB blobs.
+**
+** pTarget is the target. pPatch is the patch.  The target is updated
+** in place.  The patch is read-only.
+**
+** The original RFC-7396 algorithm is this:
+**
+**   define MergePatch(Target, Patch):
+**     if Patch is an Object:
+**       if Target is not an Object:
+**         Target = {} # Ignore the contents and set it to an empty Object
+**     for each Name/Value pair in Patch:
+**         if Value is null:
+**           if Name exists in Target:
+**             remove the Name/Value pair from Target
+**         else:
+**           Target[Name] = MergePatch(Target[Name], Value)
+**       return Target
+**     else:
+**       return Patch
+**
+** Here is an equivalent algorithm restructured to show the actual
+** implementation:
+**
+** 01   define MergePatch(Target, Patch):
+** 02      if Patch is not an Object:
+** 03         return Patch
+** 04      else: // if Patch is an Object
+** 05         if Target is not an Object:
+** 06            Target = {}
+** 07      for each Name/Value pair in Patch:
+** 08         if Name exists in Target:
+** 09            if Value is null:
+** 10               remove the Name/Value pair from Target
+** 11            else
+** 12               Target[name] = MergePatch(Target[Name], Value)
+** 13         else if Value is not NULL:
+** 14            if Value is not an Object:
+** 15               Target[name] = Value
+** 16            else:
+** 17               Target[name] = MergePatch('{}',value)
+** 18      return Target
+**  |
+**  ^---- Line numbers referenced in comments in the implementation
+*/
+static int jsonMergePatch(
+  JsonParse *pTarget,      /* The JSON parser that contains the TARGET */
+  u32 iTarget,             /* Index of TARGET in pTarget->aBlob[] */
+  const JsonParse *pPatch, /* The PATCH */
+  u32 iPatch               /* Index of PATCH in pPatch->aBlob[] */
+){
+  u8 x;             /* Type of a single node */
+  u32 n, sz=0;      /* Return values from jsonbPayloadSize() */
+  u32 iTCursor;     /* Cursor position while scanning the target object */
+  u32 iTStart;      /* First label in the target object */
+  u32 iTEndBE;      /* Original first byte past end of target, before edit */
+  u32 iTEnd;        /* Current first byte past end of target */
+  u8 eTLabel;       /* Node type of the target label */
+  u32 iTLabel = 0;  /* Index of the label */
+  u32 nTLabel = 0;  /* Header size in bytes for the target label */
+  u32 szTLabel = 0; /* Size of the target label payload */
+  u32 iTValue = 0;  /* Index of the target value */
+  u32 nTValue = 0;  /* Header size of the target value */
+  u32 szTValue = 0; /* Payload size for the target value */
+
+  u32 iPCursor;     /* Cursor position while scanning the patch */
+  u32 iPEnd;        /* First byte past the end of the patch */
+  u8 ePLabel;       /* Node type of the patch label */
+  u32 iPLabel;      /* Start of patch label */
+  u32 nPLabel;      /* Size of header on the patch label */
+  u32 szPLabel;     /* Payload size of the patch label */
+  u32 iPValue;      /* Start of patch value */
+  u32 nPValue;      /* Header size for the patch value */
+  u32 szPValue;     /* Payload size of the patch value */
+
+  assert( iTarget>=0 && iTarget<pTarget->nBlob );
+  assert( iPatch>=0 && iPatch<pPatch->nBlob );
+  x = pPatch->aBlob[iPatch] & 0x0f;
+  if( x!=JSONB_OBJECT ){  /* Algorithm line 02 */
+    u32 szPatch;        /* Total size of the patch, header+payload */
+    u32 szTarget;       /* Total size of the target, header+payload */
+    n = jsonbPayloadSize(pPatch, iPatch, &sz);
+    szPatch = n+sz;
+    sz = 0;
+    n = jsonbPayloadSize(pTarget, iTarget, &sz);
+    szTarget = n+sz;
+    jsonBlobEdit(pTarget, iTarget, szTarget, pPatch->aBlob+iPatch, szPatch);
+    return pTarget->oom ? JSON_MERGE_OOM : JSON_MERGE_OK;  /* Line 03 */
+  }
+  x = pTarget->aBlob[iTarget] & 0x0f;
+  if( x!=JSONB_OBJECT ){  /* Algorithm line 05 */
+    n = jsonbPayloadSize(pTarget, iTarget, &sz);
+    jsonBlobEdit(pTarget, iTarget+n, sz, 0, 0);
+    x = pTarget->aBlob[iTarget];
+    pTarget->aBlob[iTarget] = (x & 0xf0) | JSONB_OBJECT;
+  }
+  n = jsonbPayloadSize(pPatch, iPatch, &sz);
+  if( NEVER(n==0) ) return JSON_MERGE_BADPATCH;
+  iPCursor = iPatch+n;
+  iPEnd = iPCursor+sz;
+  n = jsonbPayloadSize(pTarget, iTarget, &sz);
+  if( NEVER(n==0) ) return JSON_MERGE_BADTARGET;
+  iTStart = iTarget+n;
+  iTEndBE = iTStart+sz;
+
+  while( iPCursor<iPEnd ){  /* Algorithm line 07 */
+    iPLabel = iPCursor;
+    ePLabel = pPatch->aBlob[iPCursor] & 0x0f;
+    if( ePLabel<JSONB_TEXT || ePLabel>JSONB_TEXTRAW ){
+      return JSON_MERGE_BADPATCH;
+    }
+    nPLabel = jsonbPayloadSize(pPatch, iPCursor, &szPLabel);
+    if( nPLabel==0 ) return JSON_MERGE_BADPATCH;
+    iPValue = iPCursor + nPLabel + szPLabel;
+    if( iPValue>=iPEnd ) return JSON_MERGE_BADPATCH;
+    nPValue = jsonbPayloadSize(pPatch, iPValue, &szPValue);
+    if( nPValue==0 ) return JSON_MERGE_BADPATCH;
+    iPCursor = iPValue + nPValue + szPValue;
+    if( iPCursor>iPEnd ) return JSON_MERGE_BADPATCH;
+
+    iTCursor = iTStart;
+    iTEnd = iTEndBE + pTarget->delta;
+    while( iTCursor<iTEnd ){
+      int isEqual;   /* true if the patch and target labels match */
+      iTLabel = iTCursor;
+      eTLabel = pTarget->aBlob[iTCursor] & 0x0f;
+      if( eTLabel<JSONB_TEXT || eTLabel>JSONB_TEXTRAW ){
+        return JSON_MERGE_BADTARGET;
+      }
+      nTLabel = jsonbPayloadSize(pTarget, iTCursor, &szTLabel);
+      if( nTLabel==0 ) return JSON_MERGE_BADTARGET;
+      iTValue = iTLabel + nTLabel + szTLabel;
+      if( iTValue>=iTEnd ) return JSON_MERGE_BADTARGET;
+      nTValue = jsonbPayloadSize(pTarget, iTValue, &szTValue);
+      if( nTValue==0 ) return JSON_MERGE_BADTARGET;
+      if( iTValue + nTValue + szTValue > iTEnd ) return JSON_MERGE_BADTARGET;
+      isEqual = jsonLabelCompare(
+                   (const char*)&pPatch->aBlob[iPLabel+nPLabel],
+                   szPLabel,
+                   (ePLabel==JSONB_TEXT || ePLabel==JSONB_TEXTRAW),
+                   (const char*)&pTarget->aBlob[iTLabel+nTLabel],
+                   szTLabel,
+                   (eTLabel==JSONB_TEXT || eTLabel==JSONB_TEXTRAW));
+      if( isEqual ) break;
+      iTCursor = iTValue + nTValue + szTValue;
+    }
+    x = pPatch->aBlob[iPValue] & 0x0f;
+    if( iTCursor<iTEnd ){
+      /* A match was found.  Algorithm line 08 */
+      if( x==0 ){
+        /* Patch value is NULL.  Algorithm line 09 */
+        jsonBlobEdit(pTarget, iTLabel, nTLabel+szTLabel+nTValue+szTValue, 0,0);
+        /*  vvvvvv----- No OOM on a delete-only edit */
+        if( NEVER(pTarget->oom) ) return JSON_MERGE_OOM;
+      }else{
+        /* Algorithm line 12 */
+        int rc, savedDelta = pTarget->delta;
+        pTarget->delta = 0;
+        rc = jsonMergePatch(pTarget, iTValue, pPatch, iPValue);
+        if( rc ) return rc;
+        pTarget->delta += savedDelta;
+      }
+    }else if( x>0 ){  /* Algorithm line 13 */
+      /* No match and patch value is not NULL */
+      u32 szNew = szPLabel+nPLabel;
+      if( (pPatch->aBlob[iPValue] & 0x0f)!=JSONB_OBJECT ){  /* Line 14 */
+        jsonBlobEdit(pTarget, iTEnd, 0, 0, szPValue+nPValue+szNew);
+        if( pTarget->oom ) return JSON_MERGE_OOM;
+        memcpy(&pTarget->aBlob[iTEnd], &pPatch->aBlob[iPLabel], szNew);
+        memcpy(&pTarget->aBlob[iTEnd+szNew],
+               &pPatch->aBlob[iPValue], szPValue+nPValue);
+      }else{
+        int rc, savedDelta;
+        jsonBlobEdit(pTarget, iTEnd, 0, 0, szNew+1);
+        if( pTarget->oom ) return JSON_MERGE_OOM;
+        memcpy(&pTarget->aBlob[iTEnd], &pPatch->aBlob[iPLabel], szNew);
+        pTarget->aBlob[iTEnd+szNew] = 0x00;
+        savedDelta = pTarget->delta;
+        pTarget->delta = 0;
+        rc = jsonMergePatch(pTarget, iTEnd+szNew,pPatch,iPValue);
+        if( rc ) return rc;
+        pTarget->delta += savedDelta;
+      }
+    }
+  }
+  if( pTarget->delta ) jsonAfterEditSizeAdjust(pTarget, iTarget);
+  return pTarget->oom ? JSON_MERGE_OOM : JSON_MERGE_OK;
+}
+
+
+/*
+** Implementation of the json_mergepatch(JSON1,JSON2) function.  Return a JSON
+** object that is the result of running the RFC 7396 MergePatch() algorithm
+** on the two arguments.
+*/
+static void jsonPatchFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *pTarget;    /* The TARGET */
+  JsonParse *pPatch;     /* The PATCH */
+  int rc;                /* Result code */
+
+  UNUSED_PARAMETER(argc);
+  assert( argc==2 );
+  pTarget = jsonParseFuncArg(ctx, argv[0], JSON_EDITABLE);
+  if( pTarget==0 ) return;
+  pPatch = jsonParseFuncArg(ctx, argv[1], 0);
+  if( pPatch ){
+    rc = jsonMergePatch(pTarget, 0, pPatch, 0);
+    if( rc==JSON_MERGE_OK ){
+      jsonReturnParse(ctx, pTarget);
+    }else if( rc==JSON_MERGE_OOM ){
+      sqlite3_result_error_nomem(ctx);
+    }else{
+      sqlite3_result_error(ctx, "malformed JSON", -1);
+    }
+    jsonParseFree(pPatch);
+  }
+  jsonParseFree(pTarget);
+}
+
+
+/*
+** Implementation of the json_object(NAME,VALUE,...) function.  Return a JSON
+** object that contains all name/value given in arguments.  Or if any name
+** is not a string or if any value is a BLOB, throw an error.
+*/
+static void jsonObjectFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+  JsonString jx;
+  const char *z;
+  u32 n;
+
+  if( argc&1 ){
+    sqlite3_result_error(ctx, "json_object() requires an even number "
+                                  "of arguments", -1);
+    return;
+  }
+  jsonStringInit(&jx, ctx);
+  jsonAppendChar(&jx, '{');
+  for(i=0; i<argc; i+=2){
+    if( sqlite3_value_type(argv[i])!=SQLITE_TEXT ){
+      sqlite3_result_error(ctx, "json_object() labels must be TEXT", -1);
+      jsonStringReset(&jx);
+      return;
+    }
+    jsonAppendSeparator(&jx);
+    z = (const char*)sqlite3_value_text(argv[i]);
+    n = sqlite3_value_bytes(argv[i]);
+    jsonAppendString(&jx, z, n);
+    jsonAppendChar(&jx, ':');
+    jsonAppendSqlValue(&jx, argv[i+1]);
+  }
+  jsonAppendChar(&jx, '}');
+  jsonReturnString(&jx, 0, 0);
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+
+
+/*
+** json_remove(JSON, PATH, ...)
+**
+** Remove the named elements from JSON and return the result.  malformed
+** JSON or PATH arguments result in an error.
+*/
+static void jsonRemoveFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;          /* The parse */
+  const char *zPath = 0; /* Path of element to be removed */
+  int i;                 /* Loop counter */
+  u32 rc;                /* Subroutine return code */
+
+  if( argc<1 ) return;
+  p = jsonParseFuncArg(ctx, argv[0], argc>1 ? JSON_EDITABLE : 0);
+  if( p==0 ) return;
+  for(i=1; i<argc; i++){
+    zPath = (const char*)sqlite3_value_text(argv[i]);
+    if( zPath==0 ){
+      goto json_remove_done;
+    }
+    if( zPath[0]!='$' ){
+      goto json_remove_patherror;
+    }
+    if( zPath[1]==0 ){
+      /* json_remove(j,'$') returns NULL */
+      goto json_remove_done;
+    }
+    p->eEdit = JEDIT_DEL;
+    p->delta = 0;
+    rc = jsonLookupStep(p, 0, zPath+1, 0);
+    if( JSON_LOOKUP_ISERROR(rc) ){
+      if( rc==JSON_LOOKUP_NOTFOUND ){
+        continue;  /* No-op */
+      }else if( rc==JSON_LOOKUP_PATHERROR ){
+        jsonBadPathError(ctx, zPath);
+      }else{
+        sqlite3_result_error(ctx, "malformed JSON", -1);
+      }
+      goto json_remove_done;
+    }
+  }
+  jsonReturnParse(ctx, p);
+  jsonParseFree(p);
+  return;
+
+json_remove_patherror:
+  jsonBadPathError(ctx, zPath);
+
+json_remove_done:
+  jsonParseFree(p);
+  return;
+}
+
+/*
+** json_replace(JSON, PATH, VALUE, ...)
+**
+** Replace the value at PATH with VALUE.  If PATH does not already exist,
+** this routine is a no-op.  If JSON or PATH is malformed, throw an error.
+*/
+static void jsonReplaceFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  if( argc<1 ) return;
+  if( (argc&1)==0 ) {
+    jsonWrongNumArgs(ctx, "replace");
+    return;
+  }
+  jsonInsertIntoBlob(ctx, argc, argv, JEDIT_REPL);
+}
+
+
+/*
+** json_set(JSON, PATH, VALUE, ...)
+**
+** Set the value at PATH to VALUE.  Create the PATH if it does not already
+** exist.  Overwrite existing values that do exist.
+** If JSON or PATH is malformed, throw an error.
+**
+** json_insert(JSON, PATH, VALUE, ...)
+**
+** Create PATH and initialize it to VALUE.  If PATH already exists, this
+** routine is a no-op.  If JSON or PATH is malformed, throw an error.
+*/
+static void jsonSetFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+
+  int flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+  int bIsSet = (flags&JSON_ISSET)!=0;
+
+  if( argc<1 ) return;
+  if( (argc&1)==0 ) {
+    jsonWrongNumArgs(ctx, bIsSet ? "set" : "insert");
+    return;
+  }
+  jsonInsertIntoBlob(ctx, argc, argv, bIsSet ? JEDIT_SET : JEDIT_INS);
+}
+
+/*
+** json_type(JSON)
+** json_type(JSON, PATH)
+**
+** Return the top-level "type" of a JSON string.  json_type() raises an
+** error if either the JSON or PATH inputs are not well-formed.
+*/
+static void jsonTypeFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;          /* The parse */
+  const char *zPath = 0;
+  u32 i;
+
+  p = jsonParseFuncArg(ctx, argv[0], 0);
+  if( p==0 ) return;
+  if( argc==2 ){
+    zPath = (const char*)sqlite3_value_text(argv[1]);
+    if( zPath==0 ) goto json_type_done;
+    if( zPath[0]!='$' ){
+      jsonBadPathError(ctx, zPath);
+      goto json_type_done;
+    }
+    i = jsonLookupStep(p, 0, zPath+1, 0);
+    if( JSON_LOOKUP_ISERROR(i) ){
+      if( i==JSON_LOOKUP_NOTFOUND ){
+        /* no-op */
+      }else if( i==JSON_LOOKUP_PATHERROR ){
+        jsonBadPathError(ctx, zPath);
+      }else{
+        sqlite3_result_error(ctx, "malformed JSON", -1);
+      }
+      goto json_type_done;
+    }
+  }else{
+    i = 0;
+  }
+  sqlite3_result_text(ctx, jsonbType[p->aBlob[i]&0x0f], -1, SQLITE_STATIC);
+json_type_done:
+  jsonParseFree(p);
+}
+
+/*
+** json_pretty(JSON)
+** json_pretty(JSON, INDENT)
+**
+** Return text that is a pretty-printed rendering of the input JSON.
+** If the argument is not valid JSON, return NULL.
+**
+** The INDENT argument is text that is used for indentation.  If omitted,
+** it defaults to four spaces (the same as PostgreSQL).
+*/
+static void jsonPrettyFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonString s;          /* The output string */
+  JsonPretty x;          /* Pretty printing context */
+
+  memset(&x, 0, sizeof(x));
+  x.pParse = jsonParseFuncArg(ctx, argv[0], 0);
+  if( x.pParse==0 ) return;
+  x.pOut = &s;
+  jsonStringInit(&s, ctx);
+  if( argc==1 || (x.zIndent = (const char*)sqlite3_value_text(argv[1]))==0 ){
+    x.zIndent = "    ";
+    x.szIndent = 4;
+  }else{
+    x.szIndent = (u32)strlen(x.zIndent);
+  }
+  jsonTranslateBlobToPrettyText(&x, 0);
+  jsonReturnString(&s, 0, 0);
+  jsonParseFree(x.pParse);
+}
+
+/*
+** json_valid(JSON)
+** json_valid(JSON, FLAGS)
+**
+** Check the JSON argument to see if it is well-formed.  The FLAGS argument
+** encodes the various constraints on what is meant by "well-formed":
+**
+**     0x01      Canonical RFC-8259 JSON text
+**     0x02      JSON text with optional JSON-5 extensions
+**     0x04      Superficially appears to be JSONB
+**     0x08      Strictly well-formed JSONB
+**
+** If the FLAGS argument is omitted, it defaults to 1.  Useful values for
+** FLAGS include:
+**
+**    1          Strict canonical JSON text
+**    2          JSON text perhaps with JSON-5 extensions
+**    4          Superficially appears to be JSONB
+**    5          Canonical JSON text or superficial JSONB
+**    6          JSON-5 text or superficial JSONB
+**    8          Strict JSONB
+**    9          Canonical JSON text or strict JSONB
+**    10         JSON-5 text or strict JSONB
+**
+** Other flag combinations are redundant.  For example, every canonical
+** JSON text is also well-formed JSON-5 text, so FLAG values 2 and 3
+** are the same.  Similarly, any input that passes a strict JSONB validation
+** will also pass the superficial validation so 12 through 15 are the same
+** as 8 through 11 respectively.
+**
+** This routine runs in linear time to validate text and when doing strict
+** JSONB validation.  Superficial JSONB validation is constant time,
+** assuming the BLOB is already in memory.  The performance advantage
+** of superficial JSONB validation is why that option is provided.
+** Application developers can choose to do fast superficial validation or
+** slower strict validation, according to their specific needs.
+**
+** Only the lower four bits of the FLAGS argument are currently used.
+** Higher bits are reserved for future expansion.   To facilitate
+** compatibility, the current implementation raises an error if any bit
+** in FLAGS is set other than the lower four bits.
+**
+** The original circa 2015 implementation of the JSON routines in
+** SQLite only supported canonical RFC-8259 JSON text and the json_valid()
+** function only accepted one argument.  That is why the default value
+** for the FLAGS argument is 1, since FLAGS=1 causes this routine to only
+** recognize canonical RFC-8259 JSON text as valid.  The extra FLAGS
+** argument was added when the JSON routines were extended to support
+** JSON5-like extensions and binary JSONB stored in BLOBs.
+**
+** Return Values:
+**
+**   *   Raise an error if FLAGS is outside the range of 1 to 15.
+**   *   Return NULL if the input is NULL
+**   *   Return 1 if the input is well-formed.
+**   *   Return 0 if the input is not well-formed.
+*/
+static void jsonValidFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;          /* The parse */
+  u8 flags = 1;
+  u8 res = 0;
+  if( argc==2 ){
+    i64 f = sqlite3_value_int64(argv[1]);
+    if( f<1 || f>15 ){
+      sqlite3_result_error(ctx, "FLAGS parameter to json_valid() must be"
+                                " between 1 and 15", -1);
+      return;
+    }
+    flags = f & 0x0f;
+  }
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_NULL: {
+#ifdef SQLITE_LEGACY_JSON_VALID
+      /* Incorrect legacy behavior was to return FALSE for a NULL input */
+      sqlite3_result_int(ctx, 0);
+#endif
+      return;
+    }
+    case SQLITE_BLOB: {
+      if( jsonFuncArgMightBeBinary(argv[0]) ){
+        if( flags & 0x04 ){
+          /* Superficial checking only - accomplished by the
+          ** jsonFuncArgMightBeBinary() call above. */
+          res = 1;
+        }else if( flags & 0x08 ){
+          /* Strict checking.  Check by translating BLOB->TEXT->BLOB.  If
+          ** no errors occur, call that a "strict check". */
+          JsonParse px;
+          u32 iErr;
+          memset(&px, 0, sizeof(px));
+          px.aBlob = (u8*)sqlite3_value_blob(argv[0]);
+          px.nBlob = sqlite3_value_bytes(argv[0]);
+          iErr = jsonbValidityCheck(&px, 0, px.nBlob, 1);
+          res = iErr==0;
+        }
+        break;
+      }
+      /* Fall through into interpreting the input as text.  See note
+      ** above at tag-20240123-a. */
+      /* no break */ deliberate_fall_through
+    }
+    default: {
+      JsonParse px;
+      if( (flags & 0x3)==0 ) break;
+      memset(&px, 0, sizeof(px));
+
+      p = jsonParseFuncArg(ctx, argv[0], JSON_KEEPERROR);
+      if( p ){
+        if( p->oom ){
+          sqlite3_result_error_nomem(ctx);
+        }else if( p->nErr ){
+          /* no-op */
+        }else if( (flags & 0x02)!=0 || p->hasNonstd==0 ){
+          res = 1;
+        }
+        jsonParseFree(p);
+      }else{
+        sqlite3_result_error_nomem(ctx);
+      }
+      break;
+    }
+  }
+  sqlite3_result_int(ctx, res);
+}
+
+/*
+** json_error_position(JSON)
+**
+** If the argument is NULL, return NULL
+**
+** If the argument is BLOB, do a full validity check and return non-zero
+** if the check fails.  The return value is the approximate 1-based offset
+** to the byte of the element that contains the first error.
+**
+** Otherwise interpret the argument is TEXT (even if it is numeric) and
+** return the 1-based character position for where the parser first recognized
+** that the input was not valid JSON, or return 0 if the input text looks
+** ok.  JSON-5 extensions are accepted.
+*/
+static void jsonErrorFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  i64 iErrPos = 0;       /* Error position to be returned */
+  JsonParse s;
+
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  memset(&s, 0, sizeof(s));
+  s.db = sqlite3_context_db_handle(ctx);
+  if( jsonFuncArgMightBeBinary(argv[0]) ){
+    s.aBlob = (u8*)sqlite3_value_blob(argv[0]);
+    s.nBlob = sqlite3_value_bytes(argv[0]);
+    iErrPos = (i64)jsonbValidityCheck(&s, 0, s.nBlob, 1);
+  }else{
+    s.zJson = (char*)sqlite3_value_text(argv[0]);
+    if( s.zJson==0 ) return;  /* NULL input or OOM */
+    s.nJson = sqlite3_value_bytes(argv[0]);
+    if( jsonConvertTextToBlob(&s,0) ){
+      if( s.oom ){
+        iErrPos = -1;
+      }else{
+        /* Convert byte-offset s.iErr into a character offset */
+        u32 k;
+        assert( s.zJson!=0 );  /* Because s.oom is false */
+        for(k=0; k<s.iErr && ALWAYS(s.zJson[k]); k++){
+          if( (s.zJson[k] & 0xc0)!=0x80 ) iErrPos++;
+        }
+        iErrPos++;
+      }
+    }
+  }
+  jsonParseReset(&s);
+  if( iErrPos<0 ){
+    sqlite3_result_error_nomem(ctx);
+  }else{
+    sqlite3_result_int64(ctx, iErrPos);
+  }
+}
+
+/****************************************************************************
+** Aggregate SQL function implementations
+****************************************************************************/
+/*
+** json_group_array(VALUE)
+**
+** Return a JSON array composed of all values in the aggregate.
+*/
+static void jsonArrayStep(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonString *pStr;
+  UNUSED_PARAMETER(argc);
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, sizeof(*pStr));
+  if( pStr ){
+    if( pStr->zBuf==0 ){
+      jsonStringInit(pStr, ctx);
+      jsonAppendChar(pStr, '[');
+    }else if( pStr->nUsed>1 ){
+      jsonAppendChar(pStr, ',');
+    }
+    pStr->pCtx = ctx;
+    jsonAppendSqlValue(pStr, argv[0]);
+  }
+}
+static void jsonArrayCompute(sqlite3_context *ctx, int isFinal){
+  JsonString *pStr;
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, 0);
+  if( pStr ){
+    int flags;
+    pStr->pCtx = ctx;
+    jsonAppendChar(pStr, ']');
+    flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+    if( pStr->eErr ){
+      jsonReturnString(pStr, 0, 0);
+      return;
+    }else if( flags & JSON_BLOB ){
+      jsonReturnStringAsBlob(pStr);
+      if( isFinal ){
+        if( !pStr->bStatic ) sqlite3RCStrUnref(pStr->zBuf);
+      }else{
+        jsonStringTrimOneChar(pStr);
+      }
+      return;
+    }else if( isFinal ){
+      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed,
+                          pStr->bStatic ? SQLITE_TRANSIENT :
+                              sqlite3RCStrUnref);
+      pStr->bStatic = 1;
+    }else{
+      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed, SQLITE_TRANSIENT);
+      jsonStringTrimOneChar(pStr);
+    }
+  }else{
+    sqlite3_result_text(ctx, "[]", 2, SQLITE_STATIC);
+  }
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+static void jsonArrayValue(sqlite3_context *ctx){
+  jsonArrayCompute(ctx, 0);
+}
+static void jsonArrayFinal(sqlite3_context *ctx){
+  jsonArrayCompute(ctx, 1);
+}
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** This method works for both json_group_array() and json_group_object().
+** It works by removing the first element of the group by searching forward
+** to the first comma (",") that is not within a string and deleting all
+** text through that comma.
+*/
+static void jsonGroupInverse(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  unsigned int i;
+  int inStr = 0;
+  int nNest = 0;
+  char *z;
+  char c;
+  JsonString *pStr;
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, 0);
+#ifdef NEVER
+  /* pStr is always non-NULL since jsonArrayStep() or jsonObjectStep() will
+  ** always have been called to initialize it */
+  if( NEVER(!pStr) ) return;
+#endif
+  z = pStr->zBuf;
+  for(i=1; i<pStr->nUsed && ((c = z[i])!=',' || inStr || nNest); i++){
+    if( c=='"' ){
+      inStr = !inStr;
+    }else if( c=='\\' ){
+      i++;
+    }else if( !inStr ){
+      if( c=='{' || c=='[' ) nNest++;
+      if( c=='}' || c==']' ) nNest--;
+    }
+  }
+  if( i<pStr->nUsed ){
+    pStr->nUsed -= i;
+    memmove(&z[1], &z[i+1], (size_t)pStr->nUsed-1);
+    z[pStr->nUsed] = 0;
+  }else{
+    pStr->nUsed = 1;
+  }
+}
+#else
+# define jsonGroupInverse 0
+#endif
+
+
+/*
+** json_group_obj(NAME,VALUE)
+**
+** Return a JSON object composed of all names and values in the aggregate.
+*/
+static void jsonObjectStep(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonString *pStr;
+  const char *z;
+  u32 n;
+  UNUSED_PARAMETER(argc);
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, sizeof(*pStr));
+  if( pStr ){
+    if( pStr->zBuf==0 ){
+      jsonStringInit(pStr, ctx);
+      jsonAppendChar(pStr, '{');
+    }else if( pStr->nUsed>1 ){
+      jsonAppendChar(pStr, ',');
+    }
+    pStr->pCtx = ctx;
+    z = (const char*)sqlite3_value_text(argv[0]);
+    n = sqlite3Strlen30(z);
+    jsonAppendString(pStr, z, n);
+    jsonAppendChar(pStr, ':');
+    jsonAppendSqlValue(pStr, argv[1]);
+  }
+}
+static void jsonObjectCompute(sqlite3_context *ctx, int isFinal){
+  JsonString *pStr;
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, 0);
+  if( pStr ){
+    int flags;
+    jsonAppendChar(pStr, '}');
+    pStr->pCtx = ctx;
+    flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+    if( pStr->eErr ){
+      jsonReturnString(pStr, 0, 0);
+      return;
+    }else if( flags & JSON_BLOB ){
+      jsonReturnStringAsBlob(pStr);
+      if( isFinal ){
+        if( !pStr->bStatic ) sqlite3RCStrUnref(pStr->zBuf);
+      }else{
+        jsonStringTrimOneChar(pStr);
+      }
+      return;
+    }else if( isFinal ){
+      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed,
+                          pStr->bStatic ? SQLITE_TRANSIENT :
+                          sqlite3RCStrUnref);
+      pStr->bStatic = 1;
+    }else{
+      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed, SQLITE_TRANSIENT);
+      jsonStringTrimOneChar(pStr);
+    }
+  }else{
+    sqlite3_result_text(ctx, "{}", 2, SQLITE_STATIC);
+  }
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+static void jsonObjectValue(sqlite3_context *ctx){
+  jsonObjectCompute(ctx, 0);
+}
+static void jsonObjectFinal(sqlite3_context *ctx){
+  jsonObjectCompute(ctx, 1);
+}
+
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/****************************************************************************
+** The json_each virtual table
+****************************************************************************/
+typedef struct JsonParent JsonParent;
+struct JsonParent {
+  u32 iHead;                 /* Start of object or array */
+  u32 iValue;                /* Start of the value */
+  u32 iEnd;                  /* First byte past the end */
+  u32 nPath;                 /* Length of path */
+  i64 iKey;                  /* Key for JSONB_ARRAY */
+};
+
+typedef struct JsonEachCursor JsonEachCursor;
+struct JsonEachCursor {
+  sqlite3_vtab_cursor base;  /* Base class - must be first */
+  u32 iRowid;                /* The rowid */
+  u32 i;                     /* Index in sParse.aBlob[] of current row */
+  u32 iEnd;                  /* EOF when i equals or exceeds this value */
+  u32 nRoot;                 /* Size of the root path in bytes */
+  u8 eType;                  /* Type of the container for element i */
+  u8 bRecursive;             /* True for json_tree().  False for json_each() */
+  u32 nParent;               /* Current nesting depth */
+  u32 nParentAlloc;          /* Space allocated for aParent[] */
+  JsonParent *aParent;       /* Parent elements of i */
+  sqlite3 *db;               /* Database connection */
+  JsonString path;           /* Current path */
+  JsonParse sParse;          /* Parse of the input JSON */
+};
+typedef struct JsonEachConnection JsonEachConnection;
+struct JsonEachConnection {
+  sqlite3_vtab base;         /* Base class - must be first */
+  sqlite3 *db;               /* Database connection */
+};
+
+
+/* Constructor for the json_each virtual table */
+static int jsonEachConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  JsonEachConnection *pNew;
+  int rc;
+
+/* Column numbers */
+#define JEACH_KEY     0
+#define JEACH_VALUE   1
+#define JEACH_TYPE    2
+#define JEACH_ATOM    3
+#define JEACH_ID      4
+#define JEACH_PARENT  5
+#define JEACH_FULLKEY 6
+#define JEACH_PATH    7
+/* The xBestIndex method assumes that the JSON and ROOT columns are
+** the last two columns in the table.  Should this ever changes, be
+** sure to update the xBestIndex method. */
+#define JEACH_JSON    8
+#define JEACH_ROOT    9
+
+  UNUSED_PARAMETER(pzErr);
+  UNUSED_PARAMETER(argv);
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(pAux);
+  rc = sqlite3_declare_vtab(db,
+     "CREATE TABLE x(key,value,type,atom,id,parent,fullkey,path,"
+                    "json HIDDEN,root HIDDEN)");
+  if( rc==SQLITE_OK ){
+    pNew = (JsonEachConnection*)sqlite3DbMallocZero(db, sizeof(*pNew));
+    *ppVtab = (sqlite3_vtab*)pNew;
+    if( pNew==0 ) return SQLITE_NOMEM;
+    sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
+    pNew->db = db;
+  }
+  return rc;
+}
+
+/* destructor for json_each virtual table */
+static int jsonEachDisconnect(sqlite3_vtab *pVtab){
+  JsonEachConnection *p = (JsonEachConnection*)pVtab;
+  sqlite3DbFree(p->db, pVtab);
+  return SQLITE_OK;
+}
+
+/* constructor for a JsonEachCursor object for json_each(). */
+static int jsonEachOpenEach(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+  JsonEachConnection *pVtab = (JsonEachConnection*)p;
+  JsonEachCursor *pCur;
+
+  UNUSED_PARAMETER(p);
+  pCur = sqlite3DbMallocZero(pVtab->db, sizeof(*pCur));
+  if( pCur==0 ) return SQLITE_NOMEM;
+  pCur->db = pVtab->db;
+  jsonStringZero(&pCur->path);
+  *ppCursor = &pCur->base;
+  return SQLITE_OK;
+}
+
+/* constructor for a JsonEachCursor object for json_tree(). */
+static int jsonEachOpenTree(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+  int rc = jsonEachOpenEach(p, ppCursor);
+  if( rc==SQLITE_OK ){
+    JsonEachCursor *pCur = (JsonEachCursor*)*ppCursor;
+    pCur->bRecursive = 1;
+  }
+  return rc;
+}
+
+/* Reset a JsonEachCursor back to its original state.  Free any memory
+** held. */
+static void jsonEachCursorReset(JsonEachCursor *p){
+  jsonParseReset(&p->sParse);
+  jsonStringReset(&p->path);
+  sqlite3DbFree(p->db, p->aParent);
+  p->iRowid = 0;
+  p->i = 0;
+  p->aParent = 0;
+  p->nParent = 0;
+  p->nParentAlloc = 0;
+  p->iEnd = 0;
+  p->eType = 0;
+}
+
+/* Destructor for a jsonEachCursor object */
+static int jsonEachClose(sqlite3_vtab_cursor *cur){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  jsonEachCursorReset(p);
+
+  sqlite3DbFree(p->db, cur);
+  return SQLITE_OK;
+}
+
+/* Return TRUE if the jsonEachCursor object has been advanced off the end
+** of the JSON object */
+static int jsonEachEof(sqlite3_vtab_cursor *cur){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  return p->i >= p->iEnd;
+}
+
+/*
+** If the cursor is currently pointing at the label of a object entry,
+** then return the index of the value.  For all other cases, return the
+** current pointer position, which is the value.
+*/
+static int jsonSkipLabel(JsonEachCursor *p){
+  if( p->eType==JSONB_OBJECT ){
+    u32 sz = 0;
+    u32 n = jsonbPayloadSize(&p->sParse, p->i, &sz);
+    return p->i + n + sz;
+  }else{
+    return p->i;
+  }
+}
+
+/*
+** Append the path name for the current element.
+*/
+static void jsonAppendPathName(JsonEachCursor *p){
+  assert( p->nParent>0 );
+  assert( p->eType==JSONB_ARRAY || p->eType==JSONB_OBJECT );
+  if( p->eType==JSONB_ARRAY ){
+    jsonPrintf(30, &p->path, "[%lld]", p->aParent[p->nParent-1].iKey);
+  }else{
+    u32 n, sz = 0, k, i;
+    const char *z;
+    int needQuote = 0;
+    n = jsonbPayloadSize(&p->sParse, p->i, &sz);
+    k = p->i + n;
+    z = (const char*)&p->sParse.aBlob[k];
+    if( sz==0 || !sqlite3Isalpha(z[0]) ){
+      needQuote = 1;
+    }else{
+      for(i=0; i<sz; i++){
+        if( !sqlite3Isalnum(z[i]) ){
+          needQuote = 1;
+          break;
+        }
+      }
+    }
+    if( needQuote ){
+      jsonPrintf(sz+4,&p->path,".\"%.*s\"", sz, z);
+    }else{
+      jsonPrintf(sz+2,&p->path,".%.*s", sz, z);
+    }
+  }
+}
+
+/* Advance the cursor to the next element for json_tree() */
+static int jsonEachNext(sqlite3_vtab_cursor *cur){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  int rc = SQLITE_OK;
+  if( p->bRecursive ){
+    u8 x;
+    u8 levelChange = 0;
+    u32 n, sz = 0;
+    u32 i = jsonSkipLabel(p);
+    x = p->sParse.aBlob[i] & 0x0f;
+    n = jsonbPayloadSize(&p->sParse, i, &sz);
+    if( x==JSONB_OBJECT || x==JSONB_ARRAY ){
+      JsonParent *pParent;
+      if( p->nParent>=p->nParentAlloc ){
+        JsonParent *pNew;
+        u64 nNew;
+        nNew = p->nParentAlloc*2 + 3;
+        pNew = sqlite3DbRealloc(p->db, p->aParent, sizeof(JsonParent)*nNew);
+        if( pNew==0 ) return SQLITE_NOMEM;
+        p->nParentAlloc = (u32)nNew;
+        p->aParent = pNew;
+      }
+      levelChange = 1;
+      pParent = &p->aParent[p->nParent];
+      pParent->iHead = p->i;
+      pParent->iValue = i;
+      pParent->iEnd = i + n + sz;
+      pParent->iKey = -1;
+      pParent->nPath = (u32)p->path.nUsed;
+      if( p->eType && p->nParent ){
+        jsonAppendPathName(p);
+        if( p->path.eErr ) rc = SQLITE_NOMEM;
+      }
+      p->nParent++;
+      p->i = i + n;
+    }else{
+      p->i = i + n + sz;
+    }
+    while( p->nParent>0 && p->i >= p->aParent[p->nParent-1].iEnd ){
+      p->nParent--;
+      p->path.nUsed = p->aParent[p->nParent].nPath;
+      levelChange = 1;
+    }
+    if( levelChange ){
+      if( p->nParent>0 ){
+        JsonParent *pParent = &p->aParent[p->nParent-1];
+        u32 iVal = pParent->iValue;
+        p->eType = p->sParse.aBlob[iVal] & 0x0f;
+      }else{
+        p->eType = 0;
+      }
+    }
+  }else{
+    u32 n, sz = 0;
+    u32 i = jsonSkipLabel(p);
+    n = jsonbPayloadSize(&p->sParse, i, &sz);
+    p->i = i + n + sz;
+  }
+  if( p->eType==JSONB_ARRAY && p->nParent ){
+    p->aParent[p->nParent-1].iKey++;
+  }
+  p->iRowid++;
+  return rc;
+}
+
+/* Length of the path for rowid==0 in bRecursive mode.
+*/
+static int jsonEachPathLength(JsonEachCursor *p){
+  u32 n = p->path.nUsed;
+  char *z = p->path.zBuf;
+  if( p->iRowid==0 && p->bRecursive && n>=2 ){
+    while( n>1 ){
+      n--;
+      if( z[n]=='[' || z[n]=='.' ){
+        u32 x, sz = 0;
+        char cSaved = z[n];
+        z[n] = 0;
+        assert( p->sParse.eEdit==0 );
+        x = jsonLookupStep(&p->sParse, 0, z+1, 0);
+        z[n] = cSaved;
+        if( JSON_LOOKUP_ISERROR(x) ) continue;
+        if( x + jsonbPayloadSize(&p->sParse, x, &sz) == p->i ) break;
+      }
+    }
+  }
+  return n;
+}
+
+/* Return the value of a column */
+static int jsonEachColumn(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int iColumn                 /* Which column to return */
+){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  switch( iColumn ){
+    case JEACH_KEY: {
+      if( p->nParent==0 ){
+        u32 n, j;
+        if( p->nRoot==1 ) break;
+        j = jsonEachPathLength(p);
+        n = p->nRoot - j;
+        if( n==0 ){
+          break;
+        }else if( p->path.zBuf[j]=='[' ){
+          i64 x;
+          sqlite3Atoi64(&p->path.zBuf[j+1], &x, n-1, SQLITE_UTF8);
+          sqlite3_result_int64(ctx, x);
+        }else if( p->path.zBuf[j+1]=='"' ){
+          sqlite3_result_text(ctx, &p->path.zBuf[j+2], n-3, SQLITE_TRANSIENT);
+        }else{
+          sqlite3_result_text(ctx, &p->path.zBuf[j+1], n-1, SQLITE_TRANSIENT);
+        }
+        break;
+      }
+      if( p->eType==JSONB_OBJECT ){
+        jsonReturnFromBlob(&p->sParse, p->i, ctx, 1);
+      }else{
+        assert( p->eType==JSONB_ARRAY );
+        sqlite3_result_int64(ctx, p->aParent[p->nParent-1].iKey);
+      }
+      break;
+    }
+    case JEACH_VALUE: {
+      u32 i = jsonSkipLabel(p);
+      jsonReturnFromBlob(&p->sParse, i, ctx, 1);
+      if( (p->sParse.aBlob[i] & 0x0f)>=JSONB_ARRAY ){
+        sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+      }
+      break;
+    }
+    case JEACH_TYPE: {
+      u32 i = jsonSkipLabel(p);
+      u8 eType = p->sParse.aBlob[i] & 0x0f;
+      sqlite3_result_text(ctx, jsonbType[eType], -1, SQLITE_STATIC);
+      break;
+    }
+    case JEACH_ATOM: {
+      u32 i = jsonSkipLabel(p);
+      if( (p->sParse.aBlob[i] & 0x0f)<JSONB_ARRAY ){
+        jsonReturnFromBlob(&p->sParse, i, ctx, 1);
+      }
+      break;
+    }
+    case JEACH_ID: {
+      sqlite3_result_int64(ctx, (sqlite3_int64)p->i);
+      break;
+    }
+    case JEACH_PARENT: {
+      if( p->nParent>0 && p->bRecursive ){
+        sqlite3_result_int64(ctx, p->aParent[p->nParent-1].iHead);
+      }
+      break;
+    }
+    case JEACH_FULLKEY: {
+      u64 nBase = p->path.nUsed;
+      if( p->nParent ) jsonAppendPathName(p);
+      sqlite3_result_text64(ctx, p->path.zBuf, p->path.nUsed,
+                            SQLITE_TRANSIENT, SQLITE_UTF8);
+      p->path.nUsed = nBase;
+      break;
+    }
+    case JEACH_PATH: {
+      u32 n = jsonEachPathLength(p);
+      sqlite3_result_text64(ctx, p->path.zBuf, n,
+                            SQLITE_TRANSIENT, SQLITE_UTF8);
+      break;
+    }
+    default: {
+      sqlite3_result_text(ctx, p->path.zBuf, p->nRoot, SQLITE_STATIC);
+      break;
+    }
+    case JEACH_JSON: {
+      if( p->sParse.zJson==0 ){
+        sqlite3_result_blob(ctx, p->sParse.aBlob, p->sParse.nBlob,
+                            SQLITE_TRANSIENT);
+      }else{
+        sqlite3_result_text(ctx, p->sParse.zJson, -1, SQLITE_TRANSIENT);
+      }
+      break;
+    }
+  }
+  return SQLITE_OK;
+}
+
+/* Return the current rowid value */
+static int jsonEachRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  *pRowid = p->iRowid;
+  return SQLITE_OK;
+}
+
+/* The query strategy is to look for an equality constraint on the json
+** column.  Without such a constraint, the table cannot operate.  idxNum is
+** 1 if the constraint is found, 3 if the constraint and zRoot are found,
+** and 0 otherwise.
+*/
+static int jsonEachBestIndex(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  int i;                     /* Loop counter or computed array index */
+  int aIdx[2];               /* Index of constraints for JSON and ROOT */
+  int unusableMask = 0;      /* Mask of unusable JSON and ROOT constraints */
+  int idxMask = 0;           /* Mask of usable == constraints JSON and ROOT */
+  const struct sqlite3_index_constraint *pConstraint;
+
+  /* This implementation assumes that JSON and ROOT are the last two
+  ** columns in the table */
+  assert( JEACH_ROOT == JEACH_JSON+1 );
+  UNUSED_PARAMETER(tab);
+  aIdx[0] = aIdx[1] = -1;
+  pConstraint = pIdxInfo->aConstraint;
+  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
+    int iCol;
+    int iMask;
+    if( pConstraint->iColumn < JEACH_JSON ) continue;
+    iCol = pConstraint->iColumn - JEACH_JSON;
+    assert( iCol==0 || iCol==1 );
+    testcase( iCol==0 );
+    iMask = 1 << iCol;
+    if( pConstraint->usable==0 ){
+      unusableMask |= iMask;
+    }else if( pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ ){
+      aIdx[iCol] = i;
+      idxMask |= iMask;
+    }
+  }
+  if( pIdxInfo->nOrderBy>0
+   && pIdxInfo->aOrderBy[0].iColumn<0
+   && pIdxInfo->aOrderBy[0].desc==0
+  ){
+    pIdxInfo->orderByConsumed = 1;
+  }
+
+  if( (unusableMask & ~idxMask)!=0 ){
+    /* If there are any unusable constraints on JSON or ROOT, then reject
+    ** this entire plan */
+    return SQLITE_CONSTRAINT;
+  }
+  if( aIdx[0]<0 ){
+    /* No JSON input.  Leave estimatedCost at the huge value that it was
+    ** initialized to to discourage the query planner from selecting this
+    ** plan. */
+    pIdxInfo->idxNum = 0;
+  }else{
+    pIdxInfo->estimatedCost = 1.0;
+    i = aIdx[0];
+    pIdxInfo->aConstraintUsage[i].argvIndex = 1;
+    pIdxInfo->aConstraintUsage[i].omit = 1;
+    if( aIdx[1]<0 ){
+      pIdxInfo->idxNum = 1;  /* Only JSON supplied.  Plan 1 */
+    }else{
+      i = aIdx[1];
+      pIdxInfo->aConstraintUsage[i].argvIndex = 2;
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      pIdxInfo->idxNum = 3;  /* Both JSON and ROOT are supplied.  Plan 3 */
+    }
+  }
+  return SQLITE_OK;
+}
+
+/* Start a search on a new JSON string */
+static int jsonEachFilter(
+  sqlite3_vtab_cursor *cur,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  const char *zRoot = 0;
+  u32 i, n, sz;
+
+  UNUSED_PARAMETER(idxStr);
+  UNUSED_PARAMETER(argc);
+  jsonEachCursorReset(p);
+  if( idxNum==0 ) return SQLITE_OK;
+  memset(&p->sParse, 0, sizeof(p->sParse));
+  p->sParse.nJPRef = 1;
+  p->sParse.db = p->db;
+  if( jsonFuncArgMightBeBinary(argv[0]) ){
+    p->sParse.nBlob = sqlite3_value_bytes(argv[0]);
+    p->sParse.aBlob = (u8*)sqlite3_value_blob(argv[0]);
+  }else{
+    p->sParse.zJson = (char*)sqlite3_value_text(argv[0]);
+    p->sParse.nJson = sqlite3_value_bytes(argv[0]);
+    if( p->sParse.zJson==0 ){
+      p->i = p->iEnd = 0;
+      return SQLITE_OK;
+    }
+    if( jsonConvertTextToBlob(&p->sParse, 0) ){
+      if( p->sParse.oom ){
+        return SQLITE_NOMEM;
+      }
+      goto json_each_malformed_input;
+    }
+  }
+  if( idxNum==3 ){
+    zRoot = (const char*)sqlite3_value_text(argv[1]);
+    if( zRoot==0 ) return SQLITE_OK;
+    if( zRoot[0]!='$' ){
+      sqlite3_free(cur->pVtab->zErrMsg);
+      cur->pVtab->zErrMsg = jsonBadPathError(0, zRoot);
+      jsonEachCursorReset(p);
+      return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
+    }
+    p->nRoot = sqlite3Strlen30(zRoot);
+    if( zRoot[1]==0 ){
+      i = p->i = 0;
+      p->eType = 0;
+    }else{
+      i = jsonLookupStep(&p->sParse, 0, zRoot+1, 0);
+      if( JSON_LOOKUP_ISERROR(i) ){
+        if( i==JSON_LOOKUP_NOTFOUND ){
+          p->i = 0;
+          p->eType = 0;
+          p->iEnd = 0;
+          return SQLITE_OK;
+        }
+        sqlite3_free(cur->pVtab->zErrMsg);
+        cur->pVtab->zErrMsg = jsonBadPathError(0, zRoot);
+        jsonEachCursorReset(p);
+        return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
+      }
+      if( p->sParse.iLabel ){
+        p->i = p->sParse.iLabel;
+        p->eType = JSONB_OBJECT;
+      }else{
+        p->i = i;
+        p->eType = JSONB_ARRAY;
+      }
+    }
+    jsonAppendRaw(&p->path, zRoot, p->nRoot);
+  }else{
+    i = p->i = 0;
+    p->eType = 0;
+    p->nRoot = 1;
+    jsonAppendRaw(&p->path, "$", 1);
+  }
+  p->nParent = 0;
+  n = jsonbPayloadSize(&p->sParse, i, &sz);
+  p->iEnd = i+n+sz;
+  if( (p->sParse.aBlob[i] & 0x0f)>=JSONB_ARRAY && !p->bRecursive ){
+    p->i = i + n;
+    p->eType = p->sParse.aBlob[i] & 0x0f;
+    p->aParent = sqlite3DbMallocZero(p->db, sizeof(JsonParent));
+    if( p->aParent==0 ) return SQLITE_NOMEM;
+    p->nParent = 1;
+    p->nParentAlloc = 1;
+    p->aParent[0].iKey = 0;
+    p->aParent[0].iEnd = p->iEnd;
+    p->aParent[0].iHead = p->i;
+    p->aParent[0].iValue = i;
+  }
+  return SQLITE_OK;
+
+json_each_malformed_input:
+  sqlite3_free(cur->pVtab->zErrMsg);
+  cur->pVtab->zErrMsg = sqlite3_mprintf("malformed JSON");
+  jsonEachCursorReset(p);
+  return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
+}
+
+/* The methods of the json_each virtual table */
+static sqlite3_module jsonEachModule = {
+  0,                         /* iVersion */
+  0,                         /* xCreate */
+  jsonEachConnect,           /* xConnect */
+  jsonEachBestIndex,         /* xBestIndex */
+  jsonEachDisconnect,        /* xDisconnect */
+  0,                         /* xDestroy */
+  jsonEachOpenEach,          /* xOpen - open a cursor */
+  jsonEachClose,             /* xClose - close a cursor */
+  jsonEachFilter,            /* xFilter - configure scan constraints */
+  jsonEachNext,              /* xNext - advance a cursor */
+  jsonEachEof,               /* xEof - check for end of scan */
+  jsonEachColumn,            /* xColumn - read data */
+  jsonEachRowid,             /* xRowid - read data */
+  0,                         /* xUpdate */
+  0,                         /* xBegin */
+  0,                         /* xSync */
+  0,                         /* xCommit */
+  0,                         /* xRollback */
+  0,                         /* xFindMethod */
+  0,                         /* xRename */
+  0,                         /* xSavepoint */
+  0,                         /* xRelease */
+  0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
+  0                          /* xIntegrity */
+};
+
+/* The methods of the json_tree virtual table. */
+static sqlite3_module jsonTreeModule = {
+  0,                         /* iVersion */
+  0,                         /* xCreate */
+  jsonEachConnect,           /* xConnect */
+  jsonEachBestIndex,         /* xBestIndex */
+  jsonEachDisconnect,        /* xDisconnect */
+  0,                         /* xDestroy */
+  jsonEachOpenTree,          /* xOpen - open a cursor */
+  jsonEachClose,             /* xClose - close a cursor */
+  jsonEachFilter,            /* xFilter - configure scan constraints */
+  jsonEachNext,              /* xNext - advance a cursor */
+  jsonEachEof,               /* xEof - check for end of scan */
+  jsonEachColumn,            /* xColumn - read data */
+  jsonEachRowid,             /* xRowid - read data */
+  0,                         /* xUpdate */
+  0,                         /* xBegin */
+  0,                         /* xSync */
+  0,                         /* xCommit */
+  0,                         /* xRollback */
+  0,                         /* xFindMethod */
+  0,                         /* xRename */
+  0,                         /* xSavepoint */
+  0,                         /* xRelease */
+  0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
+  0                          /* xIntegrity */
+};
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#endif /* !defined(SQLITE_OMIT_JSON) */
+
+/*
+** Register JSON functions.
+*/
+SQLITE_PRIVATE void sqlite3RegisterJsonFunctions(void){
+#ifndef SQLITE_OMIT_JSON
+  static FuncDef aJsonFunc[] = {
+    /*   sqlite3_result_subtype() ----,  ,--- sqlite3_value_subtype()       */
+    /*                                |  |                                  */
+    /*             Uses cache ------, |  | ,---- Returns JSONB              */
+    /*                              | |  | |                                */
+    /*     Number of arguments ---, | |  | | ,--- Flags                     */
+    /*                            | | |  | | |                              */
+    JFUNCTION(json,               1,1,1, 0,0,0,          jsonRemoveFunc),
+    JFUNCTION(jsonb,              1,1,0, 0,1,0,          jsonRemoveFunc),
+    JFUNCTION(json_array,        -1,0,1, 1,0,0,          jsonArrayFunc),
+    JFUNCTION(jsonb_array,       -1,0,1, 1,1,0,          jsonArrayFunc),
+    JFUNCTION(json_array_length,  1,1,0, 0,0,0,          jsonArrayLengthFunc),
+    JFUNCTION(json_array_length,  2,1,0, 0,0,0,          jsonArrayLengthFunc),
+    JFUNCTION(json_error_position,1,1,0, 0,0,0,          jsonErrorFunc),
+    JFUNCTION(json_extract,      -1,1,1, 0,0,0,          jsonExtractFunc),
+    JFUNCTION(jsonb_extract,     -1,1,0, 0,1,0,          jsonExtractFunc),
+    JFUNCTION(->,                 2,1,1, 0,0,JSON_JSON,  jsonExtractFunc),
+    JFUNCTION(->>,                2,1,0, 0,0,JSON_SQL,   jsonExtractFunc),
+    JFUNCTION(json_insert,       -1,1,1, 1,0,0,          jsonSetFunc),
+    JFUNCTION(jsonb_insert,      -1,1,0, 1,1,0,          jsonSetFunc),
+    JFUNCTION(json_object,       -1,0,1, 1,0,0,          jsonObjectFunc),
+    JFUNCTION(jsonb_object,      -1,0,1, 1,1,0,          jsonObjectFunc),
+    JFUNCTION(json_patch,         2,1,1, 0,0,0,          jsonPatchFunc),
+    JFUNCTION(jsonb_patch,        2,1,0, 0,1,0,          jsonPatchFunc),
+    JFUNCTION(json_pretty,        1,1,0, 0,0,0,          jsonPrettyFunc),
+    JFUNCTION(json_pretty,        2,1,0, 0,0,0,          jsonPrettyFunc),
+    JFUNCTION(json_quote,         1,0,1, 1,0,0,          jsonQuoteFunc),
+    JFUNCTION(json_remove,       -1,1,1, 0,0,0,          jsonRemoveFunc),
+    JFUNCTION(jsonb_remove,      -1,1,0, 0,1,0,          jsonRemoveFunc),
+    JFUNCTION(json_replace,      -1,1,1, 1,0,0,          jsonReplaceFunc),
+    JFUNCTION(jsonb_replace,     -1,1,0, 1,1,0,          jsonReplaceFunc),
+    JFUNCTION(json_set,          -1,1,1, 1,0,JSON_ISSET, jsonSetFunc),
+    JFUNCTION(jsonb_set,         -1,1,0, 1,1,JSON_ISSET, jsonSetFunc),
+    JFUNCTION(json_type,          1,1,0, 0,0,0,          jsonTypeFunc),
+    JFUNCTION(json_type,          2,1,0, 0,0,0,          jsonTypeFunc),
+    JFUNCTION(json_valid,         1,1,0, 0,0,0,          jsonValidFunc),
+    JFUNCTION(json_valid,         2,1,0, 0,0,0,          jsonValidFunc),
+#if SQLITE_DEBUG
+    JFUNCTION(json_parse,         1,1,0, 0,0,0,          jsonParseFunc),
+#endif
+    WAGGREGATE(json_group_array,  1, 0, 0,
+       jsonArrayStep, jsonArrayFinal, jsonArrayValue, jsonGroupInverse,
+       SQLITE_SUBTYPE|SQLITE_RESULT_SUBTYPE|SQLITE_UTF8|
+       SQLITE_DETERMINISTIC),
+    WAGGREGATE(jsonb_group_array, 1, JSON_BLOB, 0,
+       jsonArrayStep, jsonArrayFinal, jsonArrayValue, jsonGroupInverse,
+       SQLITE_SUBTYPE|SQLITE_RESULT_SUBTYPE|SQLITE_UTF8|SQLITE_DETERMINISTIC),
+    WAGGREGATE(json_group_object, 2, 0, 0,
+       jsonObjectStep, jsonObjectFinal, jsonObjectValue, jsonGroupInverse,
+       SQLITE_SUBTYPE|SQLITE_RESULT_SUBTYPE|SQLITE_UTF8|SQLITE_DETERMINISTIC),
+    WAGGREGATE(jsonb_group_object,2, JSON_BLOB, 0,
+       jsonObjectStep, jsonObjectFinal, jsonObjectValue, jsonGroupInverse,
+       SQLITE_SUBTYPE|SQLITE_RESULT_SUBTYPE|SQLITE_UTF8|
+       SQLITE_DETERMINISTIC)
+  };
+  sqlite3InsertBuiltinFuncs(aJsonFunc, ArraySize(aJsonFunc));
+#endif
+}
+
+#if  !defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_JSON)
+/*
+** Register the JSON table-valued functions
+*/
+SQLITE_PRIVATE int sqlite3JsonTableFunctions(sqlite3 *db){
+  int rc = SQLITE_OK;
+  static const struct {
+    const char *zName;
+    sqlite3_module *pModule;
+  } aMod[] = {
+    { "json_each",            &jsonEachModule               },
+    { "json_tree",            &jsonTreeModule               },
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(aMod)/sizeof(aMod[0]) && rc==SQLITE_OK; i++){
+    rc = sqlite3_create_module(db, aMod[i].zName, aMod[i].pModule, 0);
+  }
+  return rc;
+}
+#endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_JSON) */
+
+/************** End of json.c ************************************************/
+/************** Begin file rtree.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code for implementations of the r-tree and r*-tree
+** algorithms packaged as an SQLite virtual table module.
+*/
+
+/*
+** Database Format of R-Tree Tables
+** --------------------------------
+**
+** The data structure for a single virtual r-tree table is stored in three
+** native SQLite tables declared as follows. In each case, the '%' character
+** in the table name is replaced with the user-supplied name of the r-tree
+** table.
+**
+**   CREATE TABLE %_node(nodeno INTEGER PRIMARY KEY, data BLOB)
+**   CREATE TABLE %_parent(nodeno INTEGER PRIMARY KEY, parentnode INTEGER)
+**   CREATE TABLE %_rowid(rowid INTEGER PRIMARY KEY, nodeno INTEGER, ...)
+**
+** The data for each node of the r-tree structure is stored in the %_node
+** table. For each node that is not the root node of the r-tree, there is
+** an entry in the %_parent table associating the node with its parent.
+** And for each row of data in the table, there is an entry in the %_rowid
+** table that maps from the entries rowid to the id of the node that it
+** is stored on.  If the r-tree contains auxiliary columns, those are stored
+** on the end of the %_rowid table.
+**
+** The root node of an r-tree always exists, even if the r-tree table is
+** empty. The nodeno of the root node is always 1. All other nodes in the
+** table must be the same size as the root node. The content of each node
+** is formatted as follows:
+**
+**   1. If the node is the root node (node 1), then the first 2 bytes
+**      of the node contain the tree depth as a big-endian integer.
+**      For non-root nodes, the first 2 bytes are left unused.
+**
+**   2. The next 2 bytes contain the number of entries currently
+**      stored in the node.
+**
+**   3. The remainder of the node contains the node entries. Each entry
+**      consists of a single 8-byte integer followed by an even number
+**      of 4-byte coordinates. For leaf nodes the integer is the rowid
+**      of a record. For internal nodes it is the node number of a
+**      child page.
+*/
+
+#if !defined(SQLITE_CORE) \
+  || (defined(SQLITE_ENABLE_RTREE) && !defined(SQLITE_OMIT_VIRTUALTABLE))
+
+#ifndef SQLITE_CORE
+/*   #include "sqlite3ext.h" */
+  SQLITE_EXTENSION_INIT1
+#else
+/*   #include "sqlite3.h" */
+#endif
+SQLITE_PRIVATE int sqlite3GetToken(const unsigned char*,int*); /* In the SQLite core */
+
+/*
+** If building separately, we will need some setup that is normally
+** found in sqliteInt.h
+*/
+#if !defined(SQLITE_AMALGAMATION)
+#include "sqlite3rtree.h"
+typedef sqlite3_int64 i64;
+typedef sqlite3_uint64 u64;
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+#if defined(NDEBUG) && defined(SQLITE_DEBUG)
+# undef NDEBUG
+#endif
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
+# define SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS 1
+#endif
+#if defined(SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS)
+# define ALWAYS(X)      (1)
+# define NEVER(X)       (0)
+#elif !defined(NDEBUG)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
+#else
+# define ALWAYS(X)      (X)
+# define NEVER(X)       (X)
+#endif
+#endif /* !defined(SQLITE_AMALGAMATION) */
+
+/* Macro to check for 4-byte alignment.  Only used inside of assert() */
+#ifdef SQLITE_DEBUG
+# define FOUR_BYTE_ALIGNED(X)  ((((char*)(X) - (char*)0) & 3)==0)
+#endif
+
+/* #include <string.h> */
+/* #include <stdio.h> */
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+
+/*  The following macro is used to suppress compiler warnings.
+*/
+#ifndef UNUSED_PARAMETER
+# define UNUSED_PARAMETER(x) (void)(x)
+#endif
+
+typedef struct Rtree Rtree;
+typedef struct RtreeCursor RtreeCursor;
+typedef struct RtreeNode RtreeNode;
+typedef struct RtreeCell RtreeCell;
+typedef struct RtreeConstraint RtreeConstraint;
+typedef struct RtreeMatchArg RtreeMatchArg;
+typedef struct RtreeGeomCallback RtreeGeomCallback;
+typedef union RtreeCoord RtreeCoord;
+typedef struct RtreeSearchPoint RtreeSearchPoint;
+
+/* The rtree may have between 1 and RTREE_MAX_DIMENSIONS dimensions. */
+#define RTREE_MAX_DIMENSIONS 5
+
+/* Maximum number of auxiliary columns */
+#define RTREE_MAX_AUX_COLUMN 100
+
+/* Size of hash table Rtree.aHash. This hash table is not expected to
+** ever contain very many entries, so a fixed number of buckets is
+** used.
+*/
+#define HASHSIZE 97
+
+/* The xBestIndex method of this virtual table requires an estimate of
+** the number of rows in the virtual table to calculate the costs of
+** various strategies. If possible, this estimate is loaded from the
+** sqlite_stat1 table (with RTREE_MIN_ROWEST as a hard-coded minimum).
+** Otherwise, if no sqlite_stat1 entry is available, use
+** RTREE_DEFAULT_ROWEST.
+*/
+#define RTREE_DEFAULT_ROWEST 1048576
+#define RTREE_MIN_ROWEST         100
+
+/*
+** An rtree virtual-table object.
+*/
+struct Rtree {
+  sqlite3_vtab base;          /* Base class.  Must be first */
+  sqlite3 *db;                /* Host database connection */
+  int iNodeSize;              /* Size in bytes of each node in the node table */
+  u8 nDim;                    /* Number of dimensions */
+  u8 nDim2;                   /* Twice the number of dimensions */
+  u8 eCoordType;              /* RTREE_COORD_REAL32 or RTREE_COORD_INT32 */
+  u8 nBytesPerCell;           /* Bytes consumed per cell */
+  u8 inWrTrans;               /* True if inside write transaction */
+  u8 nAux;                    /* # of auxiliary columns in %_rowid */
+#ifdef SQLITE_ENABLE_GEOPOLY
+  u8 nAuxNotNull;             /* Number of initial not-null aux columns */
+#endif
+#ifdef SQLITE_DEBUG
+  u8 bCorrupt;                /* Shadow table corruption detected */
+#endif
+  int iDepth;                 /* Current depth of the r-tree structure */
+  char *zDb;                  /* Name of database containing r-tree table */
+  char *zName;                /* Name of r-tree table */
+  char *zNodeName;            /* Name of the %_node table */
+  u32 nBusy;                  /* Current number of users of this structure */
+  i64 nRowEst;                /* Estimated number of rows in this table */
+  u32 nCursor;                /* Number of open cursors */
+  u32 nNodeRef;               /* Number RtreeNodes with positive nRef */
+  char *zReadAuxSql;          /* SQL for statement to read aux data */
+
+  /* List of nodes removed during a CondenseTree operation. List is
+  ** linked together via the pointer normally used for hash chains -
+  ** RtreeNode.pNext. RtreeNode.iNode stores the depth of the sub-tree
+  ** headed by the node (leaf nodes have RtreeNode.iNode==0).
+  */
+  RtreeNode *pDeleted;
+
+  /* Blob I/O on xxx_node */
+  sqlite3_blob *pNodeBlob;
+
+  /* Statements to read/write/delete a record from xxx_node */
+  sqlite3_stmt *pWriteNode;
+  sqlite3_stmt *pDeleteNode;
+
+  /* Statements to read/write/delete a record from xxx_rowid */
+  sqlite3_stmt *pReadRowid;
+  sqlite3_stmt *pWriteRowid;
+  sqlite3_stmt *pDeleteRowid;
+
+  /* Statements to read/write/delete a record from xxx_parent */
+  sqlite3_stmt *pReadParent;
+  sqlite3_stmt *pWriteParent;
+  sqlite3_stmt *pDeleteParent;
+
+  /* Statement for writing to the "aux:" fields, if there are any */
+  sqlite3_stmt *pWriteAux;
+
+  RtreeNode *aHash[HASHSIZE]; /* Hash table of in-memory nodes. */
+};
+
+/* Possible values for Rtree.eCoordType: */
+#define RTREE_COORD_REAL32 0
+#define RTREE_COORD_INT32  1
+
+/*
+** If SQLITE_RTREE_INT_ONLY is defined, then this virtual table will
+** only deal with integer coordinates.  No floating point operations
+** will be done.
+*/
+#ifdef SQLITE_RTREE_INT_ONLY
+  typedef sqlite3_int64 RtreeDValue;       /* High accuracy coordinate */
+  typedef int RtreeValue;                  /* Low accuracy coordinate */
+# define RTREE_ZERO 0
+#else
+  typedef double RtreeDValue;              /* High accuracy coordinate */
+  typedef float RtreeValue;                /* Low accuracy coordinate */
+# define RTREE_ZERO 0.0
+#endif
+
+/*
+** Set the Rtree.bCorrupt flag
+*/
+#ifdef SQLITE_DEBUG
+# define RTREE_IS_CORRUPT(X) ((X)->bCorrupt = 1)
+#else
+# define RTREE_IS_CORRUPT(X)
+#endif
+
+/*
+** When doing a search of an r-tree, instances of the following structure
+** record intermediate results from the tree walk.
+**
+** The id is always a node-id.  For iLevel>=1 the id is the node-id of
+** the node that the RtreeSearchPoint represents.  When iLevel==0, however,
+** the id is of the parent node and the cell that RtreeSearchPoint
+** represents is the iCell-th entry in the parent node.
+*/
+struct RtreeSearchPoint {
+  RtreeDValue rScore;    /* The score for this node.  Smallest goes first. */
+  sqlite3_int64 id;      /* Node ID */
+  u8 iLevel;             /* 0=entries.  1=leaf node.  2+ for higher */
+  u8 eWithin;            /* PARTLY_WITHIN or FULLY_WITHIN */
+  u8 iCell;              /* Cell index within the node */
+};
+
+/*
+** The minimum number of cells allowed for a node is a third of the
+** maximum. In Gutman's notation:
+**
+**     m = M/3
+**
+** If an R*-tree "Reinsert" operation is required, the same number of
+** cells are removed from the overfull node and reinserted into the tree.
+*/
+#define RTREE_MINCELLS(p) ((((p)->iNodeSize-4)/(p)->nBytesPerCell)/3)
+#define RTREE_REINSERT(p) RTREE_MINCELLS(p)
+#define RTREE_MAXCELLS 51
+
+/*
+** The smallest possible node-size is (512-64)==448 bytes. And the largest
+** supported cell size is 48 bytes (8 byte rowid + ten 4 byte coordinates).
+** Therefore all non-root nodes must contain at least 3 entries. Since
+** 3^40 is greater than 2^64, an r-tree structure always has a depth of
+** 40 or less.
+*/
+#define RTREE_MAX_DEPTH 40
+
+
+/*
+** Number of entries in the cursor RtreeNode cache.  The first entry is
+** used to cache the RtreeNode for RtreeCursor.sPoint.  The remaining
+** entries cache the RtreeNode for the first elements of the priority queue.
+*/
+#define RTREE_CACHE_SZ  5
+
+/*
+** An rtree cursor object.
+*/
+struct RtreeCursor {
+  sqlite3_vtab_cursor base;         /* Base class.  Must be first */
+  u8 atEOF;                         /* True if at end of search */
+  u8 bPoint;                        /* True if sPoint is valid */
+  u8 bAuxValid;                     /* True if pReadAux is valid */
+  int iStrategy;                    /* Copy of idxNum search parameter */
+  int nConstraint;                  /* Number of entries in aConstraint */
+  RtreeConstraint *aConstraint;     /* Search constraints. */
+  int nPointAlloc;                  /* Number of slots allocated for aPoint[] */
+  int nPoint;                       /* Number of slots used in aPoint[] */
+  int mxLevel;                      /* iLevel value for root of the tree */
+  RtreeSearchPoint *aPoint;         /* Priority queue for search points */
+  sqlite3_stmt *pReadAux;           /* Statement to read aux-data */
+  RtreeSearchPoint sPoint;          /* Cached next search point */
+  RtreeNode *aNode[RTREE_CACHE_SZ]; /* Rtree node cache */
+  u32 anQueue[RTREE_MAX_DEPTH+1];   /* Number of queued entries by iLevel */
+};
+
+/* Return the Rtree of a RtreeCursor */
+#define RTREE_OF_CURSOR(X)   ((Rtree*)((X)->base.pVtab))
+
+/*
+** A coordinate can be either a floating point number or a integer.  All
+** coordinates within a single R-Tree are always of the same time.
+*/
+union RtreeCoord {
+  RtreeValue f;      /* Floating point value */
+  int i;             /* Integer value */
+  u32 u;             /* Unsigned for byte-order conversions */
+};
+
+/*
+** The argument is an RtreeCoord. Return the value stored within the RtreeCoord
+** formatted as a RtreeDValue (double or int64). This macro assumes that local
+** variable pRtree points to the Rtree structure associated with the
+** RtreeCoord.
+*/
+#ifdef SQLITE_RTREE_INT_ONLY
+# define DCOORD(coord) ((RtreeDValue)coord.i)
+#else
+# define DCOORD(coord) (                           \
+    (pRtree->eCoordType==RTREE_COORD_REAL32) ?      \
+      ((double)coord.f) :                           \
+      ((double)coord.i)                             \
+  )
+#endif
+
+/*
+** A search constraint.
+*/
+struct RtreeConstraint {
+  int iCoord;                     /* Index of constrained coordinate */
+  int op;                         /* Constraining operation */
+  union {
+    RtreeDValue rValue;             /* Constraint value. */
+    int (*xGeom)(sqlite3_rtree_geometry*,int,RtreeDValue*,int*);
+    int (*xQueryFunc)(sqlite3_rtree_query_info*);
+  } u;
+  sqlite3_rtree_query_info *pInfo;  /* xGeom and xQueryFunc argument */
+};
+
+/* Possible values for RtreeConstraint.op */
+#define RTREE_EQ    0x41  /* A */
+#define RTREE_LE    0x42  /* B */
+#define RTREE_LT    0x43  /* C */
+#define RTREE_GE    0x44  /* D */
+#define RTREE_GT    0x45  /* E */
+#define RTREE_MATCH 0x46  /* F: Old-style sqlite3_rtree_geometry_callback() */
+#define RTREE_QUERY 0x47  /* G: New-style sqlite3_rtree_query_callback() */
+
+/* Special operators available only on cursors.  Needs to be consecutive
+** with the normal values above, but must be less than RTREE_MATCH.  These
+** are used in the cursor for contraints such as x=NULL (RTREE_FALSE) or
+** x<'xyz' (RTREE_TRUE) */
+#define RTREE_TRUE  0x3f  /* ? */
+#define RTREE_FALSE 0x40  /* @ */
+
+/*
+** An rtree structure node.
+*/
+struct RtreeNode {
+  RtreeNode *pParent;         /* Parent node */
+  i64 iNode;                  /* The node number */
+  int nRef;                   /* Number of references to this node */
+  int isDirty;                /* True if the node needs to be written to disk */
+  u8 *zData;                  /* Content of the node, as should be on disk */
+  RtreeNode *pNext;           /* Next node in this hash collision chain */
+};
+
+/* Return the number of cells in a node  */
+#define NCELL(pNode) readInt16(&(pNode)->zData[2])
+
+/*
+** A single cell from a node, deserialized
+*/
+struct RtreeCell {
+  i64 iRowid;                                 /* Node or entry ID */
+  RtreeCoord aCoord[RTREE_MAX_DIMENSIONS*2];  /* Bounding box coordinates */
+};
+
+
+/*
+** This object becomes the sqlite3_user_data() for the SQL functions
+** that are created by sqlite3_rtree_geometry_callback() and
+** sqlite3_rtree_query_callback() and which appear on the right of MATCH
+** operators in order to constrain a search.
+**
+** xGeom and xQueryFunc are the callback functions.  Exactly one of
+** xGeom and xQueryFunc fields is non-NULL, depending on whether the
+** SQL function was created using sqlite3_rtree_geometry_callback() or
+** sqlite3_rtree_query_callback().
+**
+** This object is deleted automatically by the destructor mechanism in
+** sqlite3_create_function_v2().
+*/
+struct RtreeGeomCallback {
+  int (*xGeom)(sqlite3_rtree_geometry*, int, RtreeDValue*, int*);
+  int (*xQueryFunc)(sqlite3_rtree_query_info*);
+  void (*xDestructor)(void*);
+  void *pContext;
+};
+
+/*
+** An instance of this structure (in the form of a BLOB) is returned by
+** the SQL functions that sqlite3_rtree_geometry_callback() and
+** sqlite3_rtree_query_callback() create, and is read as the right-hand
+** operand to the MATCH operator of an R-Tree.
+*/
+struct RtreeMatchArg {
+  u32 iSize;                  /* Size of this object */
+  RtreeGeomCallback cb;       /* Info about the callback functions */
+  int nParam;                 /* Number of parameters to the SQL function */
+  sqlite3_value **apSqlParam; /* Original SQL parameter values */
+  RtreeDValue aParam[1];      /* Values for parameters to the SQL function */
+};
+
+#ifndef MAX
+# define MAX(x,y) ((x) < (y) ? (y) : (x))
+#endif
+#ifndef MIN
+# define MIN(x,y) ((x) > (y) ? (y) : (x))
+#endif
+
+/* What version of GCC is being used.  0 means GCC is not being used .
+** Note that the GCC_VERSION macro will also be set correctly when using
+** clang, since clang works hard to be gcc compatible.  So the gcc
+** optimizations will also work when compiling with clang.
+*/
+#ifndef GCC_VERSION
+#if defined(__GNUC__) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define GCC_VERSION (__GNUC__*1000000+__GNUC_MINOR__*1000+__GNUC_PATCHLEVEL__)
+#else
+# define GCC_VERSION 0
+#endif
+#endif
+
+/* The testcase() macro should already be defined in the amalgamation.  If
+** it is not, make it a no-op.
+*/
+#ifndef SQLITE_AMALGAMATION
+# if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_DEBUG)
+    unsigned int sqlite3RtreeTestcase = 0;
+#   define testcase(X)  if( X ){ sqlite3RtreeTestcase += __LINE__; }
+# else
+#   define testcase(X)
+# endif
+#endif
+
+/*
+** Make sure that the compiler intrinsics we desire are enabled when
+** compiling with an appropriate version of MSVC unless prevented by
+** the SQLITE_DISABLE_INTRINSIC define.
+*/
+#if !defined(SQLITE_DISABLE_INTRINSIC)
+#  if defined(_MSC_VER) && _MSC_VER>=1400
+#    if !defined(_WIN32_WCE)
+/* #      include <intrin.h> */
+#      pragma intrinsic(_byteswap_ulong)
+#      pragma intrinsic(_byteswap_uint64)
+#    else
+/* #      include <cmnintrin.h> */
+#    endif
+#  endif
+#endif
+
+/*
+** Macros to determine whether the machine is big or little endian,
+** and whether or not that determination is run-time or compile-time.
+**
+** For best performance, an attempt is made to guess at the byte-order
+** using C-preprocessor macros.  If that is unsuccessful, or if
+** -DSQLITE_RUNTIME_BYTEORDER=1 is set, then byte-order is determined
+** at run-time.
+*/
+#ifndef SQLITE_BYTEORDER /* Replicate changes at tag-20230904a */
+# if defined(__BYTE_ORDER__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
+#   define SQLITE_BYTEORDER 4321
+# elif defined(__BYTE_ORDER__) && __BYTE_ORDER__==__ORDER_LITTLE_ENDIAN__
+#   define SQLITE_BYTEORDER 1234
+# elif defined(__BIG_ENDIAN__) && __BIG_ENDIAN__==1
+#   define SQLITE_BYTEORDER 4321
+# elif defined(i386)    || defined(__i386__)      || defined(_M_IX86) ||    \
+     defined(__x86_64)  || defined(__x86_64__)    || defined(_M_X64)  ||    \
+     defined(_M_AMD64)  || defined(_M_ARM)        || defined(__x86)   ||    \
+     defined(__ARMEL__) || defined(__AARCH64EL__) || defined(_M_ARM64)
+#   define SQLITE_BYTEORDER 1234
+# elif defined(sparc)   || defined(__ARMEB__)     || defined(__AARCH64EB__)
+#   define SQLITE_BYTEORDER 4321
+# else
+#   define SQLITE_BYTEORDER 0
+# endif
+#endif
+
+
+/* What version of MSVC is being used.  0 means MSVC is not being used */
+#ifndef MSVC_VERSION
+#if defined(_MSC_VER) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define MSVC_VERSION _MSC_VER
+#else
+# define MSVC_VERSION 0
+#endif
+#endif
+
+/*
+** Functions to deserialize a 16 bit integer, 32 bit real number and
+** 64 bit integer. The deserialized value is returned.
+*/
+static int readInt16(u8 *p){
+  return (p[0]<<8) + p[1];
+}
+static void readCoord(u8 *p, RtreeCoord *pCoord){
+  assert( FOUR_BYTE_ALIGNED(p) );
+#if SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  pCoord->u = _byteswap_ulong(*(u32*)p);
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  pCoord->u = __builtin_bswap32(*(u32*)p);
+#elif SQLITE_BYTEORDER==4321
+  pCoord->u = *(u32*)p;
+#else
+  pCoord->u = (
+    (((u32)p[0]) << 24) +
+    (((u32)p[1]) << 16) +
+    (((u32)p[2]) <<  8) +
+    (((u32)p[3]) <<  0)
+  );
+#endif
+}
+static i64 readInt64(u8 *p){
+#if SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  u64 x;
+  memcpy(&x, p, 8);
+  return (i64)_byteswap_uint64(x);
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  u64 x;
+  memcpy(&x, p, 8);
+  return (i64)__builtin_bswap64(x);
+#elif SQLITE_BYTEORDER==4321
+  i64 x;
+  memcpy(&x, p, 8);
+  return x;
+#else
+  return (i64)(
+    (((u64)p[0]) << 56) +
+    (((u64)p[1]) << 48) +
+    (((u64)p[2]) << 40) +
+    (((u64)p[3]) << 32) +
+    (((u64)p[4]) << 24) +
+    (((u64)p[5]) << 16) +
+    (((u64)p[6]) <<  8) +
+    (((u64)p[7]) <<  0)
+  );
+#endif
+}
+
+/*
+** Functions to serialize a 16 bit integer, 32 bit real number and
+** 64 bit integer. The value returned is the number of bytes written
+** to the argument buffer (always 2, 4 and 8 respectively).
+*/
+static void writeInt16(u8 *p, int i){
+  p[0] = (i>> 8)&0xFF;
+  p[1] = (i>> 0)&0xFF;
+}
+static int writeCoord(u8 *p, RtreeCoord *pCoord){
+  u32 i;
+  assert( FOUR_BYTE_ALIGNED(p) );
+  assert( sizeof(RtreeCoord)==4 );
+  assert( sizeof(u32)==4 );
+#if SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  i = __builtin_bswap32(pCoord->u);
+  memcpy(p, &i, 4);
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  i = _byteswap_ulong(pCoord->u);
+  memcpy(p, &i, 4);
+#elif SQLITE_BYTEORDER==4321
+  i = pCoord->u;
+  memcpy(p, &i, 4);
+#else
+  i = pCoord->u;
+  p[0] = (i>>24)&0xFF;
+  p[1] = (i>>16)&0xFF;
+  p[2] = (i>> 8)&0xFF;
+  p[3] = (i>> 0)&0xFF;
+#endif
+  return 4;
+}
+static int writeInt64(u8 *p, i64 i){
+#if SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  i = (i64)__builtin_bswap64((u64)i);
+  memcpy(p, &i, 8);
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  i = (i64)_byteswap_uint64((u64)i);
+  memcpy(p, &i, 8);
+#elif SQLITE_BYTEORDER==4321
+  memcpy(p, &i, 8);
+#else
+  p[0] = (i>>56)&0xFF;
+  p[1] = (i>>48)&0xFF;
+  p[2] = (i>>40)&0xFF;
+  p[3] = (i>>32)&0xFF;
+  p[4] = (i>>24)&0xFF;
+  p[5] = (i>>16)&0xFF;
+  p[6] = (i>> 8)&0xFF;
+  p[7] = (i>> 0)&0xFF;
+#endif
+  return 8;
+}
+
+/*
+** Increment the reference count of node p.
+*/
+static void nodeReference(RtreeNode *p){
+  if( p ){
+    assert( p->nRef>0 );
+    p->nRef++;
+  }
+}
+
+/*
+** Clear the content of node p (set all bytes to 0x00).
+*/
+static void nodeZero(Rtree *pRtree, RtreeNode *p){
+  memset(&p->zData[2], 0, pRtree->iNodeSize-2);
+  p->isDirty = 1;
+}
+
+/*
+** Given a node number iNode, return the corresponding key to use
+** in the Rtree.aHash table.
+*/
+static unsigned int nodeHash(i64 iNode){
+  return ((unsigned)iNode) % HASHSIZE;
+}
+
+/*
+** Search the node hash table for node iNode. If found, return a pointer
+** to it. Otherwise, return 0.
+*/
+static RtreeNode *nodeHashLookup(Rtree *pRtree, i64 iNode){
+  RtreeNode *p;
+  for(p=pRtree->aHash[nodeHash(iNode)]; p && p->iNode!=iNode; p=p->pNext);
+  return p;
+}
+
+/*
+** Add node pNode to the node hash table.
+*/
+static void nodeHashInsert(Rtree *pRtree, RtreeNode *pNode){
+  int iHash;
+  assert( pNode->pNext==0 );
+  iHash = nodeHash(pNode->iNode);
+  pNode->pNext = pRtree->aHash[iHash];
+  pRtree->aHash[iHash] = pNode;
+}
+
+/*
+** Remove node pNode from the node hash table.
+*/
+static void nodeHashDelete(Rtree *pRtree, RtreeNode *pNode){
+  RtreeNode **pp;
+  if( pNode->iNode!=0 ){
+    pp = &pRtree->aHash[nodeHash(pNode->iNode)];
+    for( ; (*pp)!=pNode; pp = &(*pp)->pNext){ assert(*pp); }
+    *pp = pNode->pNext;
+    pNode->pNext = 0;
+  }
+}
+
+/*
+** Allocate and return new r-tree node. Initially, (RtreeNode.iNode==0),
+** indicating that node has not yet been assigned a node number. It is
+** assigned a node number when nodeWrite() is called to write the
+** node contents out to the database.
+*/
+static RtreeNode *nodeNew(Rtree *pRtree, RtreeNode *pParent){
+  RtreeNode *pNode;
+  pNode = (RtreeNode *)sqlite3_malloc64(sizeof(RtreeNode) + pRtree->iNodeSize);
+  if( pNode ){
+    memset(pNode, 0, sizeof(RtreeNode) + pRtree->iNodeSize);
+    pNode->zData = (u8 *)&pNode[1];
+    pNode->nRef = 1;
+    pRtree->nNodeRef++;
+    pNode->pParent = pParent;
+    pNode->isDirty = 1;
+    nodeReference(pParent);
+  }
+  return pNode;
+}
+
+/*
+** Clear the Rtree.pNodeBlob object
+*/
+static void nodeBlobReset(Rtree *pRtree){
+  sqlite3_blob *pBlob = pRtree->pNodeBlob;
+  pRtree->pNodeBlob = 0;
+  sqlite3_blob_close(pBlob);
+}
+
+/*
+** Obtain a reference to an r-tree node.
+*/
+static int nodeAcquire(
+  Rtree *pRtree,             /* R-tree structure */
+  i64 iNode,                 /* Node number to load */
+  RtreeNode *pParent,        /* Either the parent node or NULL */
+  RtreeNode **ppNode         /* OUT: Acquired node */
+){
+  int rc = SQLITE_OK;
+  RtreeNode *pNode = 0;
+
+  /* Check if the requested node is already in the hash table. If so,
+  ** increase its reference count and return it.
+  */
+  if( (pNode = nodeHashLookup(pRtree, iNode))!=0 ){
+    if( pParent && ALWAYS(pParent!=pNode->pParent) ){
+      RTREE_IS_CORRUPT(pRtree);
+      return SQLITE_CORRUPT_VTAB;
+    }
+    pNode->nRef++;
+    *ppNode = pNode;
+    return SQLITE_OK;
+  }
+
+  if( pRtree->pNodeBlob ){
+    sqlite3_blob *pBlob = pRtree->pNodeBlob;
+    pRtree->pNodeBlob = 0;
+    rc = sqlite3_blob_reopen(pBlob, iNode);
+    pRtree->pNodeBlob = pBlob;
+    if( rc ){
+      nodeBlobReset(pRtree);
+      if( rc==SQLITE_NOMEM ) return SQLITE_NOMEM;
+    }
+  }
+  if( pRtree->pNodeBlob==0 ){
+    rc = sqlite3_blob_open(pRtree->db, pRtree->zDb, pRtree->zNodeName,
+                           "data", iNode, 0,
+                           &pRtree->pNodeBlob);
+  }
+  if( rc ){
+    *ppNode = 0;
+    /* If unable to open an sqlite3_blob on the desired row, that can only
+    ** be because the shadow tables hold erroneous data. */
+    if( rc==SQLITE_ERROR ){
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+    }
+  }else if( pRtree->iNodeSize==sqlite3_blob_bytes(pRtree->pNodeBlob) ){
+    pNode = (RtreeNode *)sqlite3_malloc64(sizeof(RtreeNode)+pRtree->iNodeSize);
+    if( !pNode ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pNode->pParent = pParent;
+      pNode->zData = (u8 *)&pNode[1];
+      pNode->nRef = 1;
+      pRtree->nNodeRef++;
+      pNode->iNode = iNode;
+      pNode->isDirty = 0;
+      pNode->pNext = 0;
+      rc = sqlite3_blob_read(pRtree->pNodeBlob, pNode->zData,
+                             pRtree->iNodeSize, 0);
+    }
+  }
+
+  /* If the root node was just loaded, set pRtree->iDepth to the height
+  ** of the r-tree structure. A height of zero means all data is stored on
+  ** the root node. A height of one means the children of the root node
+  ** are the leaves, and so on. If the depth as specified on the root node
+  ** is greater than RTREE_MAX_DEPTH, the r-tree structure must be corrupt.
+  */
+  if( rc==SQLITE_OK && pNode && iNode==1 ){
+    pRtree->iDepth = readInt16(pNode->zData);
+    if( pRtree->iDepth>RTREE_MAX_DEPTH ){
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+    }
+  }
+
+  /* If no error has occurred so far, check if the "number of entries"
+  ** field on the node is too large. If so, set the return code to
+  ** SQLITE_CORRUPT_VTAB.
+  */
+  if( pNode && rc==SQLITE_OK ){
+    if( NCELL(pNode)>((pRtree->iNodeSize-4)/pRtree->nBytesPerCell) ){
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( pNode!=0 ){
+      nodeReference(pParent);
+      nodeHashInsert(pRtree, pNode);
+    }else{
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+    }
+    *ppNode = pNode;
+  }else{
+    nodeBlobReset(pRtree);
+    if( pNode ){
+      pRtree->nNodeRef--;
+      sqlite3_free(pNode);
+    }
+    *ppNode = 0;
+  }
+
+  return rc;
+}
+
+/*
+** Overwrite cell iCell of node pNode with the contents of pCell.
+*/
+static void nodeOverwriteCell(
+  Rtree *pRtree,             /* The overall R-Tree */
+  RtreeNode *pNode,          /* The node into which the cell is to be written */
+  RtreeCell *pCell,          /* The cell to write */
+  int iCell                  /* Index into pNode into which pCell is written */
+){
+  int ii;
+  u8 *p = &pNode->zData[4 + pRtree->nBytesPerCell*iCell];
+  p += writeInt64(p, pCell->iRowid);
+  for(ii=0; ii<pRtree->nDim2; ii++){
+    p += writeCoord(p, &pCell->aCoord[ii]);
+  }
+  pNode->isDirty = 1;
+}
+
+/*
+** Remove the cell with index iCell from node pNode.
+*/
+static void nodeDeleteCell(Rtree *pRtree, RtreeNode *pNode, int iCell){
+  u8 *pDst = &pNode->zData[4 + pRtree->nBytesPerCell*iCell];
+  u8 *pSrc = &pDst[pRtree->nBytesPerCell];
+  int nByte = (NCELL(pNode) - iCell - 1) * pRtree->nBytesPerCell;
+  memmove(pDst, pSrc, nByte);
+  writeInt16(&pNode->zData[2], NCELL(pNode)-1);
+  pNode->isDirty = 1;
+}
+
+/*
+** Insert the contents of cell pCell into node pNode. If the insert
+** is successful, return SQLITE_OK.
+**
+** If there is not enough free space in pNode, return SQLITE_FULL.
+*/
+static int nodeInsertCell(
+  Rtree *pRtree,                /* The overall R-Tree */
+  RtreeNode *pNode,             /* Write new cell into this node */
+  RtreeCell *pCell              /* The cell to be inserted */
+){
+  int nCell;                    /* Current number of cells in pNode */
+  int nMaxCell;                 /* Maximum number of cells for pNode */
+
+  nMaxCell = (pRtree->iNodeSize-4)/pRtree->nBytesPerCell;
+  nCell = NCELL(pNode);
+
+  assert( nCell<=nMaxCell );
+  if( nCell<nMaxCell ){
+    nodeOverwriteCell(pRtree, pNode, pCell, nCell);
+    writeInt16(&pNode->zData[2], nCell+1);
+    pNode->isDirty = 1;
+  }
+
+  return (nCell==nMaxCell);
+}
+
+/*
+** If the node is dirty, write it out to the database.
+*/
+static int nodeWrite(Rtree *pRtree, RtreeNode *pNode){
+  int rc = SQLITE_OK;
+  if( pNode->isDirty ){
+    sqlite3_stmt *p = pRtree->pWriteNode;
+    if( pNode->iNode ){
+      sqlite3_bind_int64(p, 1, pNode->iNode);
+    }else{
+      sqlite3_bind_null(p, 1);
+    }
+    sqlite3_bind_blob(p, 2, pNode->zData, pRtree->iNodeSize, SQLITE_STATIC);
+    sqlite3_step(p);
+    pNode->isDirty = 0;
+    rc = sqlite3_reset(p);
+    sqlite3_bind_null(p, 2);
+    if( pNode->iNode==0 && rc==SQLITE_OK ){
+      pNode->iNode = sqlite3_last_insert_rowid(pRtree->db);
+      nodeHashInsert(pRtree, pNode);
+    }
+  }
+  return rc;
+}
+
+/*
+** Release a reference to a node. If the node is dirty and the reference
+** count drops to zero, the node data is written to the database.
+*/
+static int nodeRelease(Rtree *pRtree, RtreeNode *pNode){
+  int rc = SQLITE_OK;
+  if( pNode ){
+    assert( pNode->nRef>0 );
+    assert( pRtree->nNodeRef>0 );
+    pNode->nRef--;
+    if( pNode->nRef==0 ){
+      pRtree->nNodeRef--;
+      if( pNode->iNode==1 ){
+        pRtree->iDepth = -1;
+      }
+      if( pNode->pParent ){
+        rc = nodeRelease(pRtree, pNode->pParent);
+      }
+      if( rc==SQLITE_OK ){
+        rc = nodeWrite(pRtree, pNode);
+      }
+      nodeHashDelete(pRtree, pNode);
+      sqlite3_free(pNode);
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the 64-bit integer value associated with cell iCell of
+** node pNode. If pNode is a leaf node, this is a rowid. If it is
+** an internal node, then the 64-bit integer is a child page number.
+*/
+static i64 nodeGetRowid(
+  Rtree *pRtree,       /* The overall R-Tree */
+  RtreeNode *pNode,    /* The node from which to extract the ID */
+  int iCell            /* The cell index from which to extract the ID */
+){
+  assert( iCell<NCELL(pNode) );
+  return readInt64(&pNode->zData[4 + pRtree->nBytesPerCell*iCell]);
+}
+
+/*
+** Return coordinate iCoord from cell iCell in node pNode.
+*/
+static void nodeGetCoord(
+  Rtree *pRtree,               /* The overall R-Tree */
+  RtreeNode *pNode,            /* The node from which to extract a coordinate */
+  int iCell,                   /* The index of the cell within the node */
+  int iCoord,                  /* Which coordinate to extract */
+  RtreeCoord *pCoord           /* OUT: Space to write result to */
+){
+  assert( iCell<NCELL(pNode) );
+  readCoord(&pNode->zData[12 + pRtree->nBytesPerCell*iCell + 4*iCoord], pCoord);
+}
+
+/*
+** Deserialize cell iCell of node pNode. Populate the structure pointed
+** to by pCell with the results.
+*/
+static void nodeGetCell(
+  Rtree *pRtree,               /* The overall R-Tree */
+  RtreeNode *pNode,            /* The node containing the cell to be read */
+  int iCell,                   /* Index of the cell within the node */
+  RtreeCell *pCell             /* OUT: Write the cell contents here */
+){
+  u8 *pData;
+  RtreeCoord *pCoord;
+  int ii = 0;
+  pCell->iRowid = nodeGetRowid(pRtree, pNode, iCell);
+  pData = pNode->zData + (12 + pRtree->nBytesPerCell*iCell);
+  pCoord = pCell->aCoord;
+  do{
+    readCoord(pData, &pCoord[ii]);
+    readCoord(pData+4, &pCoord[ii+1]);
+    pData += 8;
+    ii += 2;
+  }while( ii<pRtree->nDim2 );
+}
+
+
+/* Forward declaration for the function that does the work of
+** the virtual table module xCreate() and xConnect() methods.
+*/
+static int rtreeInit(
+  sqlite3 *, void *, int, const char *const*, sqlite3_vtab **, char **, int
+);
+
+/*
+** Rtree virtual table module xCreate method.
+*/
+static int rtreeCreate(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  return rtreeInit(db, pAux, argc, argv, ppVtab, pzErr, 1);
+}
+
+/*
+** Rtree virtual table module xConnect method.
+*/
+static int rtreeConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  return rtreeInit(db, pAux, argc, argv, ppVtab, pzErr, 0);
+}
+
+/*
+** Increment the r-tree reference count.
+*/
+static void rtreeReference(Rtree *pRtree){
+  pRtree->nBusy++;
+}
+
+/*
+** Decrement the r-tree reference count. When the reference count reaches
+** zero the structure is deleted.
+*/
+static void rtreeRelease(Rtree *pRtree){
+  pRtree->nBusy--;
+  if( pRtree->nBusy==0 ){
+    pRtree->inWrTrans = 0;
+    assert( pRtree->nCursor==0 );
+    nodeBlobReset(pRtree);
+    assert( pRtree->nNodeRef==0 || pRtree->bCorrupt );
+    sqlite3_finalize(pRtree->pWriteNode);
+    sqlite3_finalize(pRtree->pDeleteNode);
+    sqlite3_finalize(pRtree->pReadRowid);
+    sqlite3_finalize(pRtree->pWriteRowid);
+    sqlite3_finalize(pRtree->pDeleteRowid);
+    sqlite3_finalize(pRtree->pReadParent);
+    sqlite3_finalize(pRtree->pWriteParent);
+    sqlite3_finalize(pRtree->pDeleteParent);
+    sqlite3_finalize(pRtree->pWriteAux);
+    sqlite3_free(pRtree->zReadAuxSql);
+    sqlite3_free(pRtree);
+  }
+}
+
+/*
+** Rtree virtual table module xDisconnect method.
+*/
+static int rtreeDisconnect(sqlite3_vtab *pVtab){
+  rtreeRelease((Rtree *)pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** Rtree virtual table module xDestroy method.
+*/
+static int rtreeDestroy(sqlite3_vtab *pVtab){
+  Rtree *pRtree = (Rtree *)pVtab;
+  int rc;
+  char *zCreate = sqlite3_mprintf(
+    "DROP TABLE '%q'.'%q_node';"
+    "DROP TABLE '%q'.'%q_rowid';"
+    "DROP TABLE '%q'.'%q_parent';",
+    pRtree->zDb, pRtree->zName,
+    pRtree->zDb, pRtree->zName,
+    pRtree->zDb, pRtree->zName
+  );
+  if( !zCreate ){
+    rc = SQLITE_NOMEM;
+  }else{
+    nodeBlobReset(pRtree);
+    rc = sqlite3_exec(pRtree->db, zCreate, 0, 0, 0);
+    sqlite3_free(zCreate);
+  }
+  if( rc==SQLITE_OK ){
+    rtreeRelease(pRtree);
+  }
+
+  return rc;
+}
+
+/*
+** Rtree virtual table module xOpen method.
+*/
+static int rtreeOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+  int rc = SQLITE_NOMEM;
+  Rtree *pRtree = (Rtree *)pVTab;
+  RtreeCursor *pCsr;
+
+  pCsr = (RtreeCursor *)sqlite3_malloc64(sizeof(RtreeCursor));
+  if( pCsr ){
+    memset(pCsr, 0, sizeof(RtreeCursor));
+    pCsr->base.pVtab = pVTab;
+    rc = SQLITE_OK;
+    pRtree->nCursor++;
+  }
+  *ppCursor = (sqlite3_vtab_cursor *)pCsr;
+
+  return rc;
+}
+
+
+/*
+** Reset a cursor back to its initial state.
+*/
+static void resetCursor(RtreeCursor *pCsr){
+  Rtree *pRtree = (Rtree *)(pCsr->base.pVtab);
+  int ii;
+  sqlite3_stmt *pStmt;
+  if( pCsr->aConstraint ){
+    int i;                        /* Used to iterate through constraint array */
+    for(i=0; i<pCsr->nConstraint; i++){
+      sqlite3_rtree_query_info *pInfo = pCsr->aConstraint[i].pInfo;
+      if( pInfo ){
+        if( pInfo->xDelUser ) pInfo->xDelUser(pInfo->pUser);
+        sqlite3_free(pInfo);
+      }
+    }
+    sqlite3_free(pCsr->aConstraint);
+    pCsr->aConstraint = 0;
+  }
+  for(ii=0; ii<RTREE_CACHE_SZ; ii++) nodeRelease(pRtree, pCsr->aNode[ii]);
+  sqlite3_free(pCsr->aPoint);
+  pStmt = pCsr->pReadAux;
+  memset(pCsr, 0, sizeof(RtreeCursor));
+  pCsr->base.pVtab = (sqlite3_vtab*)pRtree;
+  pCsr->pReadAux = pStmt;
+
+}
+
+/*
+** Rtree virtual table module xClose method.
+*/
+static int rtreeClose(sqlite3_vtab_cursor *cur){
+  Rtree *pRtree = (Rtree *)(cur->pVtab);
+  RtreeCursor *pCsr = (RtreeCursor *)cur;
+  assert( pRtree->nCursor>0 );
+  resetCursor(pCsr);
+  sqlite3_finalize(pCsr->pReadAux);
+  sqlite3_free(pCsr);
+  pRtree->nCursor--;
+  if( pRtree->nCursor==0 && pRtree->inWrTrans==0 ){
+    nodeBlobReset(pRtree);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Rtree virtual table module xEof method.
+**
+** Return non-zero if the cursor does not currently point to a valid
+** record (i.e if the scan has finished), or zero otherwise.
+*/
+static int rtreeEof(sqlite3_vtab_cursor *cur){
+  RtreeCursor *pCsr = (RtreeCursor *)cur;
+  return pCsr->atEOF;
+}
+
+/*
+** Convert raw bits from the on-disk RTree record into a coordinate value.
+** The on-disk format is big-endian and needs to be converted for little-
+** endian platforms.  The on-disk record stores integer coordinates if
+** eInt is true and it stores 32-bit floating point records if eInt is
+** false.  a[] is the four bytes of the on-disk record to be decoded.
+** Store the results in "r".
+**
+** There are five versions of this macro.  The last one is generic.  The
+** other four are various architectures-specific optimizations.
+*/
+#if SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    c.u = _byteswap_ulong(*(u32*)a);                            \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    c.u = __builtin_bswap32(*(u32*)a);                          \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#elif SQLITE_BYTEORDER==1234
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    memcpy(&c.u,a,4);                                           \
+    c.u = ((c.u>>24)&0xff)|((c.u>>8)&0xff00)|                   \
+          ((c.u&0xff)<<24)|((c.u&0xff00)<<8);                   \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#elif SQLITE_BYTEORDER==4321
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    memcpy(&c.u,a,4);                                           \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#else
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    c.u = ((u32)a[0]<<24) + ((u32)a[1]<<16)                     \
+           +((u32)a[2]<<8) + a[3];                              \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#endif
+
+/*
+** Check the RTree node or entry given by pCellData and p against the MATCH
+** constraint pConstraint.
+*/
+static int rtreeCallbackConstraint(
+  RtreeConstraint *pConstraint,  /* The constraint to test */
+  int eInt,                      /* True if RTree holding integer coordinates */
+  u8 *pCellData,                 /* Raw cell content */
+  RtreeSearchPoint *pSearch,     /* Container of this cell */
+  sqlite3_rtree_dbl *prScore,    /* OUT: score for the cell */
+  int *peWithin                  /* OUT: visibility of the cell */
+){
+  sqlite3_rtree_query_info *pInfo = pConstraint->pInfo; /* Callback info */
+  int nCoord = pInfo->nCoord;                           /* No. of coordinates */
+  int rc;                                             /* Callback return code */
+  RtreeCoord c;                                       /* Translator union */
+  sqlite3_rtree_dbl aCoord[RTREE_MAX_DIMENSIONS*2];   /* Decoded coordinates */
+
+  assert( pConstraint->op==RTREE_MATCH || pConstraint->op==RTREE_QUERY );
+  assert( nCoord==2 || nCoord==4 || nCoord==6 || nCoord==8 || nCoord==10 );
+
+  if( pConstraint->op==RTREE_QUERY && pSearch->iLevel==1 ){
+    pInfo->iRowid = readInt64(pCellData);
+  }
+  pCellData += 8;
+#ifndef SQLITE_RTREE_INT_ONLY
+  if( eInt==0 ){
+    switch( nCoord ){
+      case 10:  readCoord(pCellData+36, &c); aCoord[9] = c.f;
+                readCoord(pCellData+32, &c); aCoord[8] = c.f;
+      case 8:   readCoord(pCellData+28, &c); aCoord[7] = c.f;
+                readCoord(pCellData+24, &c); aCoord[6] = c.f;
+      case 6:   readCoord(pCellData+20, &c); aCoord[5] = c.f;
+                readCoord(pCellData+16, &c); aCoord[4] = c.f;
+      case 4:   readCoord(pCellData+12, &c); aCoord[3] = c.f;
+                readCoord(pCellData+8,  &c); aCoord[2] = c.f;
+      default:  readCoord(pCellData+4,  &c); aCoord[1] = c.f;
+                readCoord(pCellData,    &c); aCoord[0] = c.f;
+    }
+  }else
+#endif
+  {
+    switch( nCoord ){
+      case 10:  readCoord(pCellData+36, &c); aCoord[9] = c.i;
+                readCoord(pCellData+32, &c); aCoord[8] = c.i;
+      case 8:   readCoord(pCellData+28, &c); aCoord[7] = c.i;
+                readCoord(pCellData+24, &c); aCoord[6] = c.i;
+      case 6:   readCoord(pCellData+20, &c); aCoord[5] = c.i;
+                readCoord(pCellData+16, &c); aCoord[4] = c.i;
+      case 4:   readCoord(pCellData+12, &c); aCoord[3] = c.i;
+                readCoord(pCellData+8,  &c); aCoord[2] = c.i;
+      default:  readCoord(pCellData+4,  &c); aCoord[1] = c.i;
+                readCoord(pCellData,    &c); aCoord[0] = c.i;
+    }
+  }
+  if( pConstraint->op==RTREE_MATCH ){
+    int eWithin = 0;
+    rc = pConstraint->u.xGeom((sqlite3_rtree_geometry*)pInfo,
+                              nCoord, aCoord, &eWithin);
+    if( eWithin==0 ) *peWithin = NOT_WITHIN;
+    *prScore = RTREE_ZERO;
+  }else{
+    pInfo->aCoord = aCoord;
+    pInfo->iLevel = pSearch->iLevel - 1;
+    pInfo->rScore = pInfo->rParentScore = pSearch->rScore;
+    pInfo->eWithin = pInfo->eParentWithin = pSearch->eWithin;
+    rc = pConstraint->u.xQueryFunc(pInfo);
+    if( pInfo->eWithin<*peWithin ) *peWithin = pInfo->eWithin;
+    if( pInfo->rScore<*prScore || *prScore<RTREE_ZERO ){
+      *prScore = pInfo->rScore;
+    }
+  }
+  return rc;
+}
+
+/*
+** Check the internal RTree node given by pCellData against constraint p.
+** If this constraint cannot be satisfied by any child within the node,
+** set *peWithin to NOT_WITHIN.
+*/
+static void rtreeNonleafConstraint(
+  RtreeConstraint *p,        /* The constraint to test */
+  int eInt,                  /* True if RTree holds integer coordinates */
+  u8 *pCellData,             /* Raw cell content as appears on disk */
+  int *peWithin              /* Adjust downward, as appropriate */
+){
+  sqlite3_rtree_dbl val;     /* Coordinate value convert to a double */
+
+  /* p->iCoord might point to either a lower or upper bound coordinate
+  ** in a coordinate pair.  But make pCellData point to the lower bound.
+  */
+  pCellData += 8 + 4*(p->iCoord&0xfe);
+
+  assert(p->op==RTREE_LE || p->op==RTREE_LT || p->op==RTREE_GE
+      || p->op==RTREE_GT || p->op==RTREE_EQ || p->op==RTREE_TRUE
+      || p->op==RTREE_FALSE );
+  assert( FOUR_BYTE_ALIGNED(pCellData) );
+  switch( p->op ){
+    case RTREE_TRUE:  return;   /* Always satisfied */
+    case RTREE_FALSE: break;    /* Never satisfied */
+    case RTREE_EQ:
+      RTREE_DECODE_COORD(eInt, pCellData, val);
+      /* val now holds the lower bound of the coordinate pair */
+      if( p->u.rValue>=val ){
+        pCellData += 4;
+        RTREE_DECODE_COORD(eInt, pCellData, val);
+        /* val now holds the upper bound of the coordinate pair */
+        if( p->u.rValue<=val ) return;
+      }
+      break;
+    case RTREE_LE:
+    case RTREE_LT:
+      RTREE_DECODE_COORD(eInt, pCellData, val);
+      /* val now holds the lower bound of the coordinate pair */
+      if( p->u.rValue>=val ) return;
+      break;
+
+    default:
+      pCellData += 4;
+      RTREE_DECODE_COORD(eInt, pCellData, val);
+      /* val now holds the upper bound of the coordinate pair */
+      if( p->u.rValue<=val ) return;
+      break;
+  }
+  *peWithin = NOT_WITHIN;
+}
+
+/*
+** Check the leaf RTree cell given by pCellData against constraint p.
+** If this constraint is not satisfied, set *peWithin to NOT_WITHIN.
+** If the constraint is satisfied, leave *peWithin unchanged.
+**
+** The constraint is of the form:  xN op $val
+**
+** The op is given by p->op.  The xN is p->iCoord-th coordinate in
+** pCellData.  $val is given by p->u.rValue.
+*/
+static void rtreeLeafConstraint(
+  RtreeConstraint *p,        /* The constraint to test */
+  int eInt,                  /* True if RTree holds integer coordinates */
+  u8 *pCellData,             /* Raw cell content as appears on disk */
+  int *peWithin              /* Adjust downward, as appropriate */
+){
+  RtreeDValue xN;      /* Coordinate value converted to a double */
+
+  assert(p->op==RTREE_LE || p->op==RTREE_LT || p->op==RTREE_GE
+      || p->op==RTREE_GT || p->op==RTREE_EQ || p->op==RTREE_TRUE
+      || p->op==RTREE_FALSE );
+  pCellData += 8 + p->iCoord*4;
+  assert( FOUR_BYTE_ALIGNED(pCellData) );
+  RTREE_DECODE_COORD(eInt, pCellData, xN);
+  switch( p->op ){
+    case RTREE_TRUE:  return;   /* Always satisfied */
+    case RTREE_FALSE: break;    /* Never satisfied */
+    case RTREE_LE:    if( xN <= p->u.rValue ) return;  break;
+    case RTREE_LT:    if( xN <  p->u.rValue ) return;  break;
+    case RTREE_GE:    if( xN >= p->u.rValue ) return;  break;
+    case RTREE_GT:    if( xN >  p->u.rValue ) return;  break;
+    default:          if( xN == p->u.rValue ) return;  break;
+  }
+  *peWithin = NOT_WITHIN;
+}
+
+/*
+** One of the cells in node pNode is guaranteed to have a 64-bit
+** integer value equal to iRowid. Return the index of this cell.
+*/
+static int nodeRowidIndex(
+  Rtree *pRtree,
+  RtreeNode *pNode,
+  i64 iRowid,
+  int *piIndex
+){
+  int ii;
+  int nCell = NCELL(pNode);
+  assert( nCell<200 );
+  for(ii=0; ii<nCell; ii++){
+    if( nodeGetRowid(pRtree, pNode, ii)==iRowid ){
+      *piIndex = ii;
+      return SQLITE_OK;
+    }
+  }
+  RTREE_IS_CORRUPT(pRtree);
+  return SQLITE_CORRUPT_VTAB;
+}
+
+/*
+** Return the index of the cell containing a pointer to node pNode
+** in its parent. If pNode is the root node, return -1.
+*/
+static int nodeParentIndex(Rtree *pRtree, RtreeNode *pNode, int *piIndex){
+  RtreeNode *pParent = pNode->pParent;
+  if( ALWAYS(pParent) ){
+    return nodeRowidIndex(pRtree, pParent, pNode->iNode, piIndex);
+  }else{
+    *piIndex = -1;
+    return SQLITE_OK;
+  }
+}
+
+/*
+** Compare two search points.  Return negative, zero, or positive if the first
+** is less than, equal to, or greater than the second.
+**
+** The rScore is the primary key.  Smaller rScore values come first.
+** If the rScore is a tie, then use iLevel as the tie breaker with smaller
+** iLevel values coming first.  In this way, if rScore is the same for all
+** SearchPoints, then iLevel becomes the deciding factor and the result
+** is a depth-first search, which is the desired default behavior.
+*/
+static int rtreeSearchPointCompare(
+  const RtreeSearchPoint *pA,
+  const RtreeSearchPoint *pB
+){
+  if( pA->rScore<pB->rScore ) return -1;
+  if( pA->rScore>pB->rScore ) return +1;
+  if( pA->iLevel<pB->iLevel ) return -1;
+  if( pA->iLevel>pB->iLevel ) return +1;
+  return 0;
+}
+
+/*
+** Interchange two search points in a cursor.
+*/
+static void rtreeSearchPointSwap(RtreeCursor *p, int i, int j){
+  RtreeSearchPoint t = p->aPoint[i];
+  assert( i<j );
+  p->aPoint[i] = p->aPoint[j];
+  p->aPoint[j] = t;
+  i++; j++;
+  if( i<RTREE_CACHE_SZ ){
+    if( j>=RTREE_CACHE_SZ ){
+      nodeRelease(RTREE_OF_CURSOR(p), p->aNode[i]);
+      p->aNode[i] = 0;
+    }else{
+      RtreeNode *pTemp = p->aNode[i];
+      p->aNode[i] = p->aNode[j];
+      p->aNode[j] = pTemp;
+    }
+  }
+}
+
+/*
+** Return the search point with the lowest current score.
+*/
+static RtreeSearchPoint *rtreeSearchPointFirst(RtreeCursor *pCur){
+  return pCur->bPoint ? &pCur->sPoint : pCur->nPoint ? pCur->aPoint : 0;
+}
+
+/*
+** Get the RtreeNode for the search point with the lowest score.
+*/
+static RtreeNode *rtreeNodeOfFirstSearchPoint(RtreeCursor *pCur, int *pRC){
+  sqlite3_int64 id;
+  int ii = 1 - pCur->bPoint;
+  assert( ii==0 || ii==1 );
+  assert( pCur->bPoint || pCur->nPoint );
+  if( pCur->aNode[ii]==0 ){
+    assert( pRC!=0 );
+    id = ii ? pCur->aPoint[0].id : pCur->sPoint.id;
+    *pRC = nodeAcquire(RTREE_OF_CURSOR(pCur), id, 0, &pCur->aNode[ii]);
+  }
+  return pCur->aNode[ii];
+}
+
+/*
+** Push a new element onto the priority queue
+*/
+static RtreeSearchPoint *rtreeEnqueue(
+  RtreeCursor *pCur,    /* The cursor */
+  RtreeDValue rScore,   /* Score for the new search point */
+  u8 iLevel             /* Level for the new search point */
+){
+  int i, j;
+  RtreeSearchPoint *pNew;
+  if( pCur->nPoint>=pCur->nPointAlloc ){
+    int nNew = pCur->nPointAlloc*2 + 8;
+    pNew = sqlite3_realloc64(pCur->aPoint, nNew*sizeof(pCur->aPoint[0]));
+    if( pNew==0 ) return 0;
+    pCur->aPoint = pNew;
+    pCur->nPointAlloc = nNew;
+  }
+  i = pCur->nPoint++;
+  pNew = pCur->aPoint + i;
+  pNew->rScore = rScore;
+  pNew->iLevel = iLevel;
+  assert( iLevel<=RTREE_MAX_DEPTH );
+  while( i>0 ){
+    RtreeSearchPoint *pParent;
+    j = (i-1)/2;
+    pParent = pCur->aPoint + j;
+    if( rtreeSearchPointCompare(pNew, pParent)>=0 ) break;
+    rtreeSearchPointSwap(pCur, j, i);
+    i = j;
+    pNew = pParent;
+  }
+  return pNew;
+}
+
+/*
+** Allocate a new RtreeSearchPoint and return a pointer to it.  Return
+** NULL if malloc fails.
+*/
+static RtreeSearchPoint *rtreeSearchPointNew(
+  RtreeCursor *pCur,    /* The cursor */
+  RtreeDValue rScore,   /* Score for the new search point */
+  u8 iLevel             /* Level for the new search point */
+){
+  RtreeSearchPoint *pNew, *pFirst;
+  pFirst = rtreeSearchPointFirst(pCur);
+  pCur->anQueue[iLevel]++;
+  if( pFirst==0
+   || pFirst->rScore>rScore
+   || (pFirst->rScore==rScore && pFirst->iLevel>iLevel)
+  ){
+    if( pCur->bPoint ){
+      int ii;
+      pNew = rtreeEnqueue(pCur, rScore, iLevel);
+      if( pNew==0 ) return 0;
+      ii = (int)(pNew - pCur->aPoint) + 1;
+      assert( ii==1 );
+      if( ALWAYS(ii<RTREE_CACHE_SZ) ){
+        assert( pCur->aNode[ii]==0 );
+        pCur->aNode[ii] = pCur->aNode[0];
+      }else{
+        nodeRelease(RTREE_OF_CURSOR(pCur), pCur->aNode[0]);
+      }
+      pCur->aNode[0] = 0;
+      *pNew = pCur->sPoint;
+    }
+    pCur->sPoint.rScore = rScore;
+    pCur->sPoint.iLevel = iLevel;
+    pCur->bPoint = 1;
+    return &pCur->sPoint;
+  }else{
+    return rtreeEnqueue(pCur, rScore, iLevel);
+  }
+}
+
+#if 0
+/* Tracing routines for the RtreeSearchPoint queue */
+static void tracePoint(RtreeSearchPoint *p, int idx, RtreeCursor *pCur){
+  if( idx<0 ){ printf(" s"); }else{ printf("%2d", idx); }
+  printf(" %d.%05lld.%02d %g %d",
+    p->iLevel, p->id, p->iCell, p->rScore, p->eWithin
+  );
+  idx++;
+  if( idx<RTREE_CACHE_SZ ){
+    printf(" %p\n", pCur->aNode[idx]);
+  }else{
+    printf("\n");
+  }
+}
+static void traceQueue(RtreeCursor *pCur, const char *zPrefix){
+  int ii;
+  printf("=== %9s ", zPrefix);
+  if( pCur->bPoint ){
+    tracePoint(&pCur->sPoint, -1, pCur);
+  }
+  for(ii=0; ii<pCur->nPoint; ii++){
+    if( ii>0 || pCur->bPoint ) printf("              ");
+    tracePoint(&pCur->aPoint[ii], ii, pCur);
+  }
+}
+# define RTREE_QUEUE_TRACE(A,B) traceQueue(A,B)
+#else
+# define RTREE_QUEUE_TRACE(A,B)   /* no-op */
+#endif
+
+/* Remove the search point with the lowest current score.
+*/
+static void rtreeSearchPointPop(RtreeCursor *p){
+  int i, j, k, n;
+  i = 1 - p->bPoint;
+  assert( i==0 || i==1 );
+  if( p->aNode[i] ){
+    nodeRelease(RTREE_OF_CURSOR(p), p->aNode[i]);
+    p->aNode[i] = 0;
+  }
+  if( p->bPoint ){
+    p->anQueue[p->sPoint.iLevel]--;
+    p->bPoint = 0;
+  }else if( ALWAYS(p->nPoint) ){
+    p->anQueue[p->aPoint[0].iLevel]--;
+    n = --p->nPoint;
+    p->aPoint[0] = p->aPoint[n];
+    if( n<RTREE_CACHE_SZ-1 ){
+      p->aNode[1] = p->aNode[n+1];
+      p->aNode[n+1] = 0;
+    }
+    i = 0;
+    while( (j = i*2+1)<n ){
+      k = j+1;
+      if( k<n && rtreeSearchPointCompare(&p->aPoint[k], &p->aPoint[j])<0 ){
+        if( rtreeSearchPointCompare(&p->aPoint[k], &p->aPoint[i])<0 ){
+          rtreeSearchPointSwap(p, i, k);
+          i = k;
+        }else{
+          break;
+        }
+      }else{
+        if( rtreeSearchPointCompare(&p->aPoint[j], &p->aPoint[i])<0 ){
+          rtreeSearchPointSwap(p, i, j);
+          i = j;
+        }else{
+          break;
+        }
+      }
+    }
+  }
+}
+
+
+/*
+** Continue the search on cursor pCur until the front of the queue
+** contains an entry suitable for returning as a result-set row,
+** or until the RtreeSearchPoint queue is empty, indicating that the
+** query has completed.
+*/
+static int rtreeStepToLeaf(RtreeCursor *pCur){
+  RtreeSearchPoint *p;
+  Rtree *pRtree = RTREE_OF_CURSOR(pCur);
+  RtreeNode *pNode;
+  int eWithin;
+  int rc = SQLITE_OK;
+  int nCell;
+  int nConstraint = pCur->nConstraint;
+  int ii;
+  int eInt;
+  RtreeSearchPoint x;
+
+  eInt = pRtree->eCoordType==RTREE_COORD_INT32;
+  while( (p = rtreeSearchPointFirst(pCur))!=0 && p->iLevel>0 ){
+    u8 *pCellData;
+    pNode = rtreeNodeOfFirstSearchPoint(pCur, &rc);
+    if( rc ) return rc;
+    nCell = NCELL(pNode);
+    assert( nCell<200 );
+    pCellData = pNode->zData + (4+pRtree->nBytesPerCell*p->iCell);
+    while( p->iCell<nCell ){
+      sqlite3_rtree_dbl rScore = (sqlite3_rtree_dbl)-1;
+      eWithin = FULLY_WITHIN;
+      for(ii=0; ii<nConstraint; ii++){
+        RtreeConstraint *pConstraint = pCur->aConstraint + ii;
+        if( pConstraint->op>=RTREE_MATCH ){
+          rc = rtreeCallbackConstraint(pConstraint, eInt, pCellData, p,
+                                       &rScore, &eWithin);
+          if( rc ) return rc;
+        }else if( p->iLevel==1 ){
+          rtreeLeafConstraint(pConstraint, eInt, pCellData, &eWithin);
+        }else{
+          rtreeNonleafConstraint(pConstraint, eInt, pCellData, &eWithin);
+        }
+        if( eWithin==NOT_WITHIN ){
+          p->iCell++;
+          pCellData += pRtree->nBytesPerCell;
+          break;
+        }
+      }
+      if( eWithin==NOT_WITHIN ) continue;
+      p->iCell++;
+      x.iLevel = p->iLevel - 1;
+      if( x.iLevel ){
+        x.id = readInt64(pCellData);
+        for(ii=0; ii<pCur->nPoint; ii++){
+          if( pCur->aPoint[ii].id==x.id ){
+            RTREE_IS_CORRUPT(pRtree);
+            return SQLITE_CORRUPT_VTAB;
+          }
+        }
+        x.iCell = 0;
+      }else{
+        x.id = p->id;
+        x.iCell = p->iCell - 1;
+      }
+      if( p->iCell>=nCell ){
+        RTREE_QUEUE_TRACE(pCur, "POP-S:");
+        rtreeSearchPointPop(pCur);
+      }
+      if( rScore<RTREE_ZERO ) rScore = RTREE_ZERO;
+      p = rtreeSearchPointNew(pCur, rScore, x.iLevel);
+      if( p==0 ) return SQLITE_NOMEM;
+      p->eWithin = (u8)eWithin;
+      p->id = x.id;
+      p->iCell = x.iCell;
+      RTREE_QUEUE_TRACE(pCur, "PUSH-S:");
+      break;
+    }
+    if( p->iCell>=nCell ){
+      RTREE_QUEUE_TRACE(pCur, "POP-Se:");
+      rtreeSearchPointPop(pCur);
+    }
+  }
+  pCur->atEOF = p==0;
+  return SQLITE_OK;
+}
+
+/*
+** Rtree virtual table module xNext method.
+*/
+static int rtreeNext(sqlite3_vtab_cursor *pVtabCursor){
+  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+  int rc = SQLITE_OK;
+
+  /* Move to the next entry that matches the configured constraints. */
+  RTREE_QUEUE_TRACE(pCsr, "POP-Nx:");
+  if( pCsr->bAuxValid ){
+    pCsr->bAuxValid = 0;
+    sqlite3_reset(pCsr->pReadAux);
+  }
+  rtreeSearchPointPop(pCsr);
+  rc = rtreeStepToLeaf(pCsr);
+  return rc;
+}
+
+/*
+** Rtree virtual table module xRowid method.
+*/
+static int rtreeRowid(sqlite3_vtab_cursor *pVtabCursor, sqlite_int64 *pRowid){
+  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+  RtreeSearchPoint *p = rtreeSearchPointFirst(pCsr);
+  int rc = SQLITE_OK;
+  RtreeNode *pNode = rtreeNodeOfFirstSearchPoint(pCsr, &rc);
+  if( rc==SQLITE_OK && ALWAYS(p) ){
+    if( p->iCell>=NCELL(pNode) ){
+      rc = SQLITE_ABORT;
+    }else{
+      *pRowid = nodeGetRowid(RTREE_OF_CURSOR(pCsr), pNode, p->iCell);
+    }
+  }
+  return rc;
+}
+
+/*
+** Rtree virtual table module xColumn method.
+*/
+static int rtreeColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
+  Rtree *pRtree = (Rtree *)cur->pVtab;
+  RtreeCursor *pCsr = (RtreeCursor *)cur;
+  RtreeSearchPoint *p = rtreeSearchPointFirst(pCsr);
+  RtreeCoord c;
+  int rc = SQLITE_OK;
+  RtreeNode *pNode = rtreeNodeOfFirstSearchPoint(pCsr, &rc);
+
+  if( rc ) return rc;
+  if( NEVER(p==0) ) return SQLITE_OK;
+  if( p->iCell>=NCELL(pNode) ) return SQLITE_ABORT;
+  if( i==0 ){
+    sqlite3_result_int64(ctx, nodeGetRowid(pRtree, pNode, p->iCell));
+  }else if( i<=pRtree->nDim2 ){
+    nodeGetCoord(pRtree, pNode, p->iCell, i-1, &c);
+#ifndef SQLITE_RTREE_INT_ONLY
+    if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+      sqlite3_result_double(ctx, c.f);
+    }else
+#endif
+    {
+      assert( pRtree->eCoordType==RTREE_COORD_INT32 );
+      sqlite3_result_int(ctx, c.i);
+    }
+  }else{
+    if( !pCsr->bAuxValid ){
+      if( pCsr->pReadAux==0 ){
+        rc = sqlite3_prepare_v3(pRtree->db, pRtree->zReadAuxSql, -1, 0,
+                                &pCsr->pReadAux, 0);
+        if( rc ) return rc;
+      }
+      sqlite3_bind_int64(pCsr->pReadAux, 1,
+          nodeGetRowid(pRtree, pNode, p->iCell));
+      rc = sqlite3_step(pCsr->pReadAux);
+      if( rc==SQLITE_ROW ){
+        pCsr->bAuxValid = 1;
+      }else{
+        sqlite3_reset(pCsr->pReadAux);
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+        return rc;
+      }
+    }
+    sqlite3_result_value(ctx,
+         sqlite3_column_value(pCsr->pReadAux, i - pRtree->nDim2 + 1));
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Use nodeAcquire() to obtain the leaf node containing the record with
+** rowid iRowid. If successful, set *ppLeaf to point to the node and
+** return SQLITE_OK. If there is no such record in the table, set
+** *ppLeaf to 0 and return SQLITE_OK. If an error occurs, set *ppLeaf
+** to zero and return an SQLite error code.
+*/
+static int findLeafNode(
+  Rtree *pRtree,              /* RTree to search */
+  i64 iRowid,                 /* The rowid searching for */
+  RtreeNode **ppLeaf,         /* Write the node here */
+  sqlite3_int64 *piNode       /* Write the node-id here */
+){
+  int rc;
+  *ppLeaf = 0;
+  sqlite3_bind_int64(pRtree->pReadRowid, 1, iRowid);
+  if( sqlite3_step(pRtree->pReadRowid)==SQLITE_ROW ){
+    i64 iNode = sqlite3_column_int64(pRtree->pReadRowid, 0);
+    if( piNode ) *piNode = iNode;
+    rc = nodeAcquire(pRtree, iNode, 0, ppLeaf);
+    sqlite3_reset(pRtree->pReadRowid);
+  }else{
+    rc = sqlite3_reset(pRtree->pReadRowid);
+  }
+  return rc;
+}
+
+/*
+** This function is called to configure the RtreeConstraint object passed
+** as the second argument for a MATCH constraint. The value passed as the
+** first argument to this function is the right-hand operand to the MATCH
+** operator.
+*/
+static int deserializeGeometry(sqlite3_value *pValue, RtreeConstraint *pCons){
+  RtreeMatchArg *pBlob, *pSrc;       /* BLOB returned by geometry function */
+  sqlite3_rtree_query_info *pInfo;   /* Callback information */
+
+  pSrc = sqlite3_value_pointer(pValue, "RtreeMatchArg");
+  if( pSrc==0 ) return SQLITE_ERROR;
+  pInfo = (sqlite3_rtree_query_info*)
+                sqlite3_malloc64( sizeof(*pInfo)+pSrc->iSize );
+  if( !pInfo ) return SQLITE_NOMEM;
+  memset(pInfo, 0, sizeof(*pInfo));
+  pBlob = (RtreeMatchArg*)&pInfo[1];
+  memcpy(pBlob, pSrc, pSrc->iSize);
+  pInfo->pContext = pBlob->cb.pContext;
+  pInfo->nParam = pBlob->nParam;
+  pInfo->aParam = pBlob->aParam;
+  pInfo->apSqlParam = pBlob->apSqlParam;
+
+  if( pBlob->cb.xGeom ){
+    pCons->u.xGeom = pBlob->cb.xGeom;
+  }else{
+    pCons->op = RTREE_QUERY;
+    pCons->u.xQueryFunc = pBlob->cb.xQueryFunc;
+  }
+  pCons->pInfo = pInfo;
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE int sqlite3IntFloatCompare(i64,double);
+
+/*
+** Rtree virtual table module xFilter method.
+*/
+static int rtreeFilter(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  Rtree *pRtree = (Rtree *)pVtabCursor->pVtab;
+  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+  RtreeNode *pRoot = 0;
+  int ii;
+  int rc = SQLITE_OK;
+  int iCell = 0;
+
+  rtreeReference(pRtree);
+
+  /* Reset the cursor to the same state as rtreeOpen() leaves it in. */
+  resetCursor(pCsr);
+
+  pCsr->iStrategy = idxNum;
+  if( idxNum==1 ){
+    /* Special case - lookup by rowid. */
+    RtreeNode *pLeaf;        /* Leaf on which the required cell resides */
+    RtreeSearchPoint *p;     /* Search point for the leaf */
+    i64 iRowid = sqlite3_value_int64(argv[0]);
+    i64 iNode = 0;
+    int eType = sqlite3_value_numeric_type(argv[0]);
+    if( eType==SQLITE_INTEGER
+     || (eType==SQLITE_FLOAT
+         && 0==sqlite3IntFloatCompare(iRowid,sqlite3_value_double(argv[0])))
+    ){
+      rc = findLeafNode(pRtree, iRowid, &pLeaf, &iNode);
+    }else{
+      rc = SQLITE_OK;
+      pLeaf = 0;
+    }
+    if( rc==SQLITE_OK && pLeaf!=0 ){
+      p = rtreeSearchPointNew(pCsr, RTREE_ZERO, 0);
+      assert( p!=0 );  /* Always returns pCsr->sPoint */
+      pCsr->aNode[0] = pLeaf;
+      p->id = iNode;
+      p->eWithin = PARTLY_WITHIN;
+      rc = nodeRowidIndex(pRtree, pLeaf, iRowid, &iCell);
+      p->iCell = (u8)iCell;
+      RTREE_QUEUE_TRACE(pCsr, "PUSH-F1:");
+    }else{
+      pCsr->atEOF = 1;
+    }
+  }else{
+    /* Normal case - r-tree scan. Set up the RtreeCursor.aConstraint array
+    ** with the configured constraints.
+    */
+    rc = nodeAcquire(pRtree, 1, 0, &pRoot);
+    if( rc==SQLITE_OK && argc>0 ){
+      pCsr->aConstraint = sqlite3_malloc64(sizeof(RtreeConstraint)*argc);
+      pCsr->nConstraint = argc;
+      if( !pCsr->aConstraint ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(pCsr->aConstraint, 0, sizeof(RtreeConstraint)*argc);
+        memset(pCsr->anQueue, 0, sizeof(u32)*(pRtree->iDepth + 1));
+        assert( (idxStr==0 && argc==0)
+                || (idxStr && (int)strlen(idxStr)==argc*2) );
+        for(ii=0; ii<argc; ii++){
+          RtreeConstraint *p = &pCsr->aConstraint[ii];
+          int eType = sqlite3_value_numeric_type(argv[ii]);
+          p->op = idxStr[ii*2];
+          p->iCoord = idxStr[ii*2+1]-'0';
+          if( p->op>=RTREE_MATCH ){
+            /* A MATCH operator. The right-hand-side must be a blob that
+            ** can be cast into an RtreeMatchArg object. One created using
+            ** an sqlite3_rtree_geometry_callback() SQL user function.
+            */
+            rc = deserializeGeometry(argv[ii], p);
+            if( rc!=SQLITE_OK ){
+              break;
+            }
+            p->pInfo->nCoord = pRtree->nDim2;
+            p->pInfo->anQueue = pCsr->anQueue;
+            p->pInfo->mxLevel = pRtree->iDepth + 1;
+          }else if( eType==SQLITE_INTEGER ){
+            sqlite3_int64 iVal = sqlite3_value_int64(argv[ii]);
+#ifdef SQLITE_RTREE_INT_ONLY
+            p->u.rValue = iVal;
+#else
+            p->u.rValue = (double)iVal;
+            if( iVal>=((sqlite3_int64)1)<<48
+             || iVal<=-(((sqlite3_int64)1)<<48)
+            ){
+              if( p->op==RTREE_LT ) p->op = RTREE_LE;
+              if( p->op==RTREE_GT ) p->op = RTREE_GE;
+            }
+#endif
+          }else if( eType==SQLITE_FLOAT ){
+#ifdef SQLITE_RTREE_INT_ONLY
+            p->u.rValue = sqlite3_value_int64(argv[ii]);
+#else
+            p->u.rValue = sqlite3_value_double(argv[ii]);
+#endif
+          }else{
+            p->u.rValue = RTREE_ZERO;
+            if( eType==SQLITE_NULL ){
+              p->op = RTREE_FALSE;
+            }else if( p->op==RTREE_LT || p->op==RTREE_LE ){
+              p->op = RTREE_TRUE;
+            }else{
+              p->op = RTREE_FALSE;
+            }
+          }
+        }
+      }
+    }
+    if( rc==SQLITE_OK ){
+      RtreeSearchPoint *pNew;
+      assert( pCsr->bPoint==0 );  /* Due to the resetCursor() call above */
+      pNew = rtreeSearchPointNew(pCsr, RTREE_ZERO, (u8)(pRtree->iDepth+1));
+      if( NEVER(pNew==0) ){       /* Because pCsr->bPoint was FALSE */
+        return SQLITE_NOMEM;
+      }
+      pNew->id = 1;
+      pNew->iCell = 0;
+      pNew->eWithin = PARTLY_WITHIN;
+      assert( pCsr->bPoint==1 );
+      pCsr->aNode[0] = pRoot;
+      pRoot = 0;
+      RTREE_QUEUE_TRACE(pCsr, "PUSH-Fm:");
+      rc = rtreeStepToLeaf(pCsr);
+    }
+  }
+
+  nodeRelease(pRtree, pRoot);
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+/*
+** Rtree virtual table module xBestIndex method. There are three
+** table scan strategies to choose from (in order from most to
+** least desirable):
+**
+**   idxNum     idxStr        Strategy
+**   ------------------------------------------------
+**     1        Unused        Direct lookup by rowid.
+**     2        See below     R-tree query or full-table scan.
+**   ------------------------------------------------
+**
+** If strategy 1 is used, then idxStr is not meaningful. If strategy
+** 2 is used, idxStr is formatted to contain 2 bytes for each
+** constraint used. The first two bytes of idxStr correspond to
+** the constraint in sqlite3_index_info.aConstraintUsage[] with
+** (argvIndex==1) etc.
+**
+** The first of each pair of bytes in idxStr identifies the constraint
+** operator as follows:
+**
+**   Operator    Byte Value
+**   ----------------------
+**      =        0x41 ('A')
+**     <=        0x42 ('B')
+**      <        0x43 ('C')
+**     >=        0x44 ('D')
+**      >        0x45 ('E')
+**   MATCH       0x46 ('F')
+**   ----------------------
+**
+** The second of each pair of bytes identifies the coordinate column
+** to which the constraint applies. The leftmost coordinate column
+** is 'a', the second from the left 'b' etc.
+*/
+static int rtreeBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  Rtree *pRtree = (Rtree*)tab;
+  int rc = SQLITE_OK;
+  int ii;
+  int bMatch = 0;                 /* True if there exists a MATCH constraint */
+  i64 nRow;                       /* Estimated rows returned by this scan */
+
+  int iIdx = 0;
+  char zIdxStr[RTREE_MAX_DIMENSIONS*8+1];
+  memset(zIdxStr, 0, sizeof(zIdxStr));
+
+  /* Check if there exists a MATCH constraint - even an unusable one. If there
+  ** is, do not consider the lookup-by-rowid plan as using such a plan would
+  ** require the VDBE to evaluate the MATCH constraint, which is not currently
+  ** possible. */
+  for(ii=0; ii<pIdxInfo->nConstraint; ii++){
+    if( pIdxInfo->aConstraint[ii].op==SQLITE_INDEX_CONSTRAINT_MATCH ){
+      bMatch = 1;
+    }
+  }
+
+  assert( pIdxInfo->idxStr==0 );
+  for(ii=0; ii<pIdxInfo->nConstraint && iIdx<(int)(sizeof(zIdxStr)-1); ii++){
+    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[ii];
+
+    if( bMatch==0 && p->usable
+     && p->iColumn<=0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ
+    ){
+      /* We have an equality constraint on the rowid. Use strategy 1. */
+      int jj;
+      for(jj=0; jj<ii; jj++){
+        pIdxInfo->aConstraintUsage[jj].argvIndex = 0;
+        pIdxInfo->aConstraintUsage[jj].omit = 0;
+      }
+      pIdxInfo->idxNum = 1;
+      pIdxInfo->aConstraintUsage[ii].argvIndex = 1;
+      pIdxInfo->aConstraintUsage[jj].omit = 1;
+
+      /* This strategy involves a two rowid lookups on an B-Tree structures
+      ** and then a linear search of an R-Tree node. This should be
+      ** considered almost as quick as a direct rowid lookup (for which
+      ** sqlite uses an internal cost of 0.0). It is expected to return
+      ** a single row.
+      */
+      pIdxInfo->estimatedCost = 30.0;
+      pIdxInfo->estimatedRows = 1;
+      pIdxInfo->idxFlags = SQLITE_INDEX_SCAN_UNIQUE;
+      return SQLITE_OK;
+    }
+
+    if( p->usable
+    && ((p->iColumn>0 && p->iColumn<=pRtree->nDim2)
+        || p->op==SQLITE_INDEX_CONSTRAINT_MATCH)
+    ){
+      u8 op;
+      u8 doOmit = 1;
+      switch( p->op ){
+        case SQLITE_INDEX_CONSTRAINT_EQ:    op = RTREE_EQ;    doOmit = 0; break;
+        case SQLITE_INDEX_CONSTRAINT_GT:    op = RTREE_GT;    doOmit = 0; break;
+        case SQLITE_INDEX_CONSTRAINT_LE:    op = RTREE_LE;    break;
+        case SQLITE_INDEX_CONSTRAINT_LT:    op = RTREE_LT;    doOmit = 0; break;
+        case SQLITE_INDEX_CONSTRAINT_GE:    op = RTREE_GE;    break;
+        case SQLITE_INDEX_CONSTRAINT_MATCH: op = RTREE_MATCH; break;
+        default:                            op = 0;           break;
+      }
+      if( op ){
+        zIdxStr[iIdx++] = op;
+        zIdxStr[iIdx++] = (char)(p->iColumn - 1 + '0');
+        pIdxInfo->aConstraintUsage[ii].argvIndex = (iIdx/2);
+        pIdxInfo->aConstraintUsage[ii].omit = doOmit;
+      }
+    }
+  }
+
+  pIdxInfo->idxNum = 2;
+  pIdxInfo->needToFreeIdxStr = 1;
+  if( iIdx>0 ){
+    pIdxInfo->idxStr = sqlite3_malloc( iIdx+1 );
+    if( pIdxInfo->idxStr==0 ){
+      return SQLITE_NOMEM;
+    }
+    memcpy(pIdxInfo->idxStr, zIdxStr, iIdx+1);
+  }
+
+  nRow = pRtree->nRowEst >> (iIdx/2);
+  pIdxInfo->estimatedCost = (double)6.0 * (double)nRow;
+  pIdxInfo->estimatedRows = nRow;
+
+  return rc;
+}
+
+/*
+** Return the N-dimensional volumn of the cell stored in *p.
+*/
+static RtreeDValue cellArea(Rtree *pRtree, RtreeCell *p){
+  RtreeDValue area = (RtreeDValue)1;
+  assert( pRtree->nDim>=1 && pRtree->nDim<=5 );
+#ifndef SQLITE_RTREE_INT_ONLY
+  if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+    switch( pRtree->nDim ){
+      case 5:  area  = p->aCoord[9].f - p->aCoord[8].f;
+      case 4:  area *= p->aCoord[7].f - p->aCoord[6].f;
+      case 3:  area *= p->aCoord[5].f - p->aCoord[4].f;
+      case 2:  area *= p->aCoord[3].f - p->aCoord[2].f;
+      default: area *= p->aCoord[1].f - p->aCoord[0].f;
+    }
+  }else
+#endif
+  {
+    switch( pRtree->nDim ){
+      case 5:  area  = (i64)p->aCoord[9].i - (i64)p->aCoord[8].i;
+      case 4:  area *= (i64)p->aCoord[7].i - (i64)p->aCoord[6].i;
+      case 3:  area *= (i64)p->aCoord[5].i - (i64)p->aCoord[4].i;
+      case 2:  area *= (i64)p->aCoord[3].i - (i64)p->aCoord[2].i;
+      default: area *= (i64)p->aCoord[1].i - (i64)p->aCoord[0].i;
+    }
+  }
+  return area;
+}
+
+/*
+** Return the margin length of cell p. The margin length is the sum
+** of the objects size in each dimension.
+*/
+static RtreeDValue cellMargin(Rtree *pRtree, RtreeCell *p){
+  RtreeDValue margin = 0;
+  int ii = pRtree->nDim2 - 2;
+  do{
+    margin += (DCOORD(p->aCoord[ii+1]) - DCOORD(p->aCoord[ii]));
+    ii -= 2;
+  }while( ii>=0 );
+  return margin;
+}
+
+/*
+** Store the union of cells p1 and p2 in p1.
+*/
+static void cellUnion(Rtree *pRtree, RtreeCell *p1, RtreeCell *p2){
+  int ii = 0;
+  if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+    do{
+      p1->aCoord[ii].f = MIN(p1->aCoord[ii].f, p2->aCoord[ii].f);
+      p1->aCoord[ii+1].f = MAX(p1->aCoord[ii+1].f, p2->aCoord[ii+1].f);
+      ii += 2;
+    }while( ii<pRtree->nDim2 );
+  }else{
+    do{
+      p1->aCoord[ii].i = MIN(p1->aCoord[ii].i, p2->aCoord[ii].i);
+      p1->aCoord[ii+1].i = MAX(p1->aCoord[ii+1].i, p2->aCoord[ii+1].i);
+      ii += 2;
+    }while( ii<pRtree->nDim2 );
+  }
+}
+
+/*
+** Return true if the area covered by p2 is a subset of the area covered
+** by p1. False otherwise.
+*/
+static int cellContains(Rtree *pRtree, RtreeCell *p1, RtreeCell *p2){
+  int ii;
+  if( pRtree->eCoordType==RTREE_COORD_INT32 ){
+    for(ii=0; ii<pRtree->nDim2; ii+=2){
+      RtreeCoord *a1 = &p1->aCoord[ii];
+      RtreeCoord *a2 = &p2->aCoord[ii];
+      if( a2[0].i<a1[0].i || a2[1].i>a1[1].i ) return 0;
+    }
+  }else{
+    for(ii=0; ii<pRtree->nDim2; ii+=2){
+      RtreeCoord *a1 = &p1->aCoord[ii];
+      RtreeCoord *a2 = &p2->aCoord[ii];
+      if( a2[0].f<a1[0].f || a2[1].f>a1[1].f ) return 0;
+    }
+  }
+  return 1;
+}
+
+static RtreeDValue cellOverlap(
+  Rtree *pRtree,
+  RtreeCell *p,
+  RtreeCell *aCell,
+  int nCell
+){
+  int ii;
+  RtreeDValue overlap = RTREE_ZERO;
+  for(ii=0; ii<nCell; ii++){
+    int jj;
+    RtreeDValue o = (RtreeDValue)1;
+    for(jj=0; jj<pRtree->nDim2; jj+=2){
+      RtreeDValue x1, x2;
+      x1 = MAX(DCOORD(p->aCoord[jj]), DCOORD(aCell[ii].aCoord[jj]));
+      x2 = MIN(DCOORD(p->aCoord[jj+1]), DCOORD(aCell[ii].aCoord[jj+1]));
+      if( x2<x1 ){
+        o = (RtreeDValue)0;
+        break;
+      }else{
+        o = o * (x2-x1);
+      }
+    }
+    overlap += o;
+  }
+  return overlap;
+}
+
+
+/*
+** This function implements the ChooseLeaf algorithm from Gutman[84].
+** ChooseSubTree in r*tree terminology.
+*/
+static int ChooseLeaf(
+  Rtree *pRtree,               /* Rtree table */
+  RtreeCell *pCell,            /* Cell to insert into rtree */
+  int iHeight,                 /* Height of sub-tree rooted at pCell */
+  RtreeNode **ppLeaf           /* OUT: Selected leaf page */
+){
+  int rc;
+  int ii;
+  RtreeNode *pNode = 0;
+  rc = nodeAcquire(pRtree, 1, 0, &pNode);
+
+  for(ii=0; rc==SQLITE_OK && ii<(pRtree->iDepth-iHeight); ii++){
+    int iCell;
+    sqlite3_int64 iBest = 0;
+    int bFound = 0;
+    RtreeDValue fMinGrowth = RTREE_ZERO;
+    RtreeDValue fMinArea = RTREE_ZERO;
+    int nCell = NCELL(pNode);
+    RtreeNode *pChild = 0;
+
+    /* First check to see if there is are any cells in pNode that completely
+    ** contains pCell.  If two or more cells in pNode completely contain pCell
+    ** then pick the smallest.
+    */
+    for(iCell=0; iCell<nCell; iCell++){
+      RtreeCell cell;
+      nodeGetCell(pRtree, pNode, iCell, &cell);
+      if( cellContains(pRtree, &cell, pCell) ){
+        RtreeDValue area = cellArea(pRtree, &cell);
+        if( bFound==0 || area<fMinArea ){
+          iBest = cell.iRowid;
+          fMinArea = area;
+          bFound = 1;
+        }
+      }
+    }
+    if( !bFound ){
+      /* No cells of pNode will completely contain pCell.  So pick the
+      ** cell of pNode that grows by the least amount when pCell is added.
+      ** Break ties by selecting the smaller cell.
+      */
+      for(iCell=0; iCell<nCell; iCell++){
+        RtreeCell cell;
+        RtreeDValue growth;
+        RtreeDValue area;
+        nodeGetCell(pRtree, pNode, iCell, &cell);
+        area = cellArea(pRtree, &cell);
+        cellUnion(pRtree, &cell, pCell);
+        growth = cellArea(pRtree, &cell)-area;
+        if( iCell==0
+         || growth<fMinGrowth
+         || (growth==fMinGrowth && area<fMinArea)
+        ){
+          fMinGrowth = growth;
+          fMinArea = area;
+          iBest = cell.iRowid;
+        }
+      }
+    }
+
+    rc = nodeAcquire(pRtree, iBest, pNode, &pChild);
+    nodeRelease(pRtree, pNode);
+    pNode = pChild;
+  }
+
+  *ppLeaf = pNode;
+  return rc;
+}
+
+/*
+** A cell with the same content as pCell has just been inserted into
+** the node pNode. This function updates the bounding box cells in
+** all ancestor elements.
+*/
+static int AdjustTree(
+  Rtree *pRtree,                    /* Rtree table */
+  RtreeNode *pNode,                 /* Adjust ancestry of this node. */
+  RtreeCell *pCell                  /* This cell was just inserted */
+){
+  RtreeNode *p = pNode;
+  int cnt = 0;
+  int rc;
+  while( p->pParent ){
+    RtreeNode *pParent = p->pParent;
+    RtreeCell cell;
+    int iCell;
+
+    cnt++;
+    if( NEVER(cnt>100) ){
+      RTREE_IS_CORRUPT(pRtree);
+      return SQLITE_CORRUPT_VTAB;
+    }
+    rc = nodeParentIndex(pRtree, p, &iCell);
+    if( NEVER(rc!=SQLITE_OK) ){
+      RTREE_IS_CORRUPT(pRtree);
+      return SQLITE_CORRUPT_VTAB;
+    }
+
+    nodeGetCell(pRtree, pParent, iCell, &cell);
+    if( !cellContains(pRtree, &cell, pCell) ){
+      cellUnion(pRtree, &cell, pCell);
+      nodeOverwriteCell(pRtree, pParent, &cell, iCell);
+    }
+
+    p = pParent;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Write mapping (iRowid->iNode) to the <rtree>_rowid table.
+*/
+static int rowidWrite(Rtree *pRtree, sqlite3_int64 iRowid, sqlite3_int64 iNode){
+  sqlite3_bind_int64(pRtree->pWriteRowid, 1, iRowid);
+  sqlite3_bind_int64(pRtree->pWriteRowid, 2, iNode);
+  sqlite3_step(pRtree->pWriteRowid);
+  return sqlite3_reset(pRtree->pWriteRowid);
+}
+
+/*
+** Write mapping (iNode->iPar) to the <rtree>_parent table.
+*/
+static int parentWrite(Rtree *pRtree, sqlite3_int64 iNode, sqlite3_int64 iPar){
+  sqlite3_bind_int64(pRtree->pWriteParent, 1, iNode);
+  sqlite3_bind_int64(pRtree->pWriteParent, 2, iPar);
+  sqlite3_step(pRtree->pWriteParent);
+  return sqlite3_reset(pRtree->pWriteParent);
+}
+
+static int rtreeInsertCell(Rtree *, RtreeNode *, RtreeCell *, int);
+
+
+
+/*
+** Arguments aIdx, aCell and aSpare all point to arrays of size
+** nIdx. The aIdx array contains the set of integers from 0 to
+** (nIdx-1) in no particular order. This function sorts the values
+** in aIdx according to dimension iDim of the cells in aCell. The
+** minimum value of dimension iDim is considered first, the
+** maximum used to break ties.
+**
+** The aSpare array is used as temporary working space by the
+** sorting algorithm.
+*/
+static void SortByDimension(
+  Rtree *pRtree,
+  int *aIdx,
+  int nIdx,
+  int iDim,
+  RtreeCell *aCell,
+  int *aSpare
+){
+  if( nIdx>1 ){
+
+    int iLeft = 0;
+    int iRight = 0;
+
+    int nLeft = nIdx/2;
+    int nRight = nIdx-nLeft;
+    int *aLeft = aIdx;
+    int *aRight = &aIdx[nLeft];
+
+    SortByDimension(pRtree, aLeft, nLeft, iDim, aCell, aSpare);
+    SortByDimension(pRtree, aRight, nRight, iDim, aCell, aSpare);
+
+    memcpy(aSpare, aLeft, sizeof(int)*nLeft);
+    aLeft = aSpare;
+    while( iLeft<nLeft || iRight<nRight ){
+      RtreeDValue xleft1 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2]);
+      RtreeDValue xleft2 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2+1]);
+      RtreeDValue xright1 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2]);
+      RtreeDValue xright2 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2+1]);
+      if( (iLeft!=nLeft) && ((iRight==nRight)
+       || (xleft1<xright1)
+       || (xleft1==xright1 && xleft2<xright2)
+      )){
+        aIdx[iLeft+iRight] = aLeft[iLeft];
+        iLeft++;
+      }else{
+        aIdx[iLeft+iRight] = aRight[iRight];
+        iRight++;
+      }
+    }
+
+#if 0
+    /* Check that the sort worked */
+    {
+      int jj;
+      for(jj=1; jj<nIdx; jj++){
+        RtreeDValue xleft1 = aCell[aIdx[jj-1]].aCoord[iDim*2];
+        RtreeDValue xleft2 = aCell[aIdx[jj-1]].aCoord[iDim*2+1];
+        RtreeDValue xright1 = aCell[aIdx[jj]].aCoord[iDim*2];
+        RtreeDValue xright2 = aCell[aIdx[jj]].aCoord[iDim*2+1];
+        assert( xleft1<=xright1 && (xleft1<xright1 || xleft2<=xright2) );
+      }
+    }
+#endif
+  }
+}
+
+/*
+** Implementation of the R*-tree variant of SplitNode from Beckman[1990].
+*/
+static int splitNodeStartree(
+  Rtree *pRtree,
+  RtreeCell *aCell,
+  int nCell,
+  RtreeNode *pLeft,
+  RtreeNode *pRight,
+  RtreeCell *pBboxLeft,
+  RtreeCell *pBboxRight
+){
+  int **aaSorted;
+  int *aSpare;
+  int ii;
+
+  int iBestDim = 0;
+  int iBestSplit = 0;
+  RtreeDValue fBestMargin = RTREE_ZERO;
+
+  sqlite3_int64 nByte = (pRtree->nDim+1)*(sizeof(int*)+nCell*sizeof(int));
+
+  aaSorted = (int **)sqlite3_malloc64(nByte);
+  if( !aaSorted ){
+    return SQLITE_NOMEM;
+  }
+
+  aSpare = &((int *)&aaSorted[pRtree->nDim])[pRtree->nDim*nCell];
+  memset(aaSorted, 0, nByte);
+  for(ii=0; ii<pRtree->nDim; ii++){
+    int jj;
+    aaSorted[ii] = &((int *)&aaSorted[pRtree->nDim])[ii*nCell];
+    for(jj=0; jj<nCell; jj++){
+      aaSorted[ii][jj] = jj;
+    }
+    SortByDimension(pRtree, aaSorted[ii], nCell, ii, aCell, aSpare);
+  }
+
+  for(ii=0; ii<pRtree->nDim; ii++){
+    RtreeDValue margin = RTREE_ZERO;
+    RtreeDValue fBestOverlap = RTREE_ZERO;
+    RtreeDValue fBestArea = RTREE_ZERO;
+    int iBestLeft = 0;
+    int nLeft;
+
+    for(
+      nLeft=RTREE_MINCELLS(pRtree);
+      nLeft<=(nCell-RTREE_MINCELLS(pRtree));
+      nLeft++
+    ){
+      RtreeCell left;
+      RtreeCell right;
+      int kk;
+      RtreeDValue overlap;
+      RtreeDValue area;
+
+      memcpy(&left, &aCell[aaSorted[ii][0]], sizeof(RtreeCell));
+      memcpy(&right, &aCell[aaSorted[ii][nCell-1]], sizeof(RtreeCell));
+      for(kk=1; kk<(nCell-1); kk++){
+        if( kk<nLeft ){
+          cellUnion(pRtree, &left, &aCell[aaSorted[ii][kk]]);
+        }else{
+          cellUnion(pRtree, &right, &aCell[aaSorted[ii][kk]]);
+        }
+      }
+      margin += cellMargin(pRtree, &left);
+      margin += cellMargin(pRtree, &right);
+      overlap = cellOverlap(pRtree, &left, &right, 1);
+      area = cellArea(pRtree, &left) + cellArea(pRtree, &right);
+      if( (nLeft==RTREE_MINCELLS(pRtree))
+       || (overlap<fBestOverlap)
+       || (overlap==fBestOverlap && area<fBestArea)
+      ){
+        iBestLeft = nLeft;
+        fBestOverlap = overlap;
+        fBestArea = area;
+      }
+    }
+
+    if( ii==0 || margin<fBestMargin ){
+      iBestDim = ii;
+      fBestMargin = margin;
+      iBestSplit = iBestLeft;
+    }
+  }
+
+  memcpy(pBboxLeft, &aCell[aaSorted[iBestDim][0]], sizeof(RtreeCell));
+  memcpy(pBboxRight, &aCell[aaSorted[iBestDim][iBestSplit]], sizeof(RtreeCell));
+  for(ii=0; ii<nCell; ii++){
+    RtreeNode *pTarget = (ii<iBestSplit)?pLeft:pRight;
+    RtreeCell *pBbox = (ii<iBestSplit)?pBboxLeft:pBboxRight;
+    RtreeCell *pCell = &aCell[aaSorted[iBestDim][ii]];
+    nodeInsertCell(pRtree, pTarget, pCell);
+    cellUnion(pRtree, pBbox, pCell);
+  }
+
+  sqlite3_free(aaSorted);
+  return SQLITE_OK;
+}
+
+
+static int updateMapping(
+  Rtree *pRtree,
+  i64 iRowid,
+  RtreeNode *pNode,
+  int iHeight
+){
+  int (*xSetMapping)(Rtree *, sqlite3_int64, sqlite3_int64);
+  xSetMapping = ((iHeight==0)?rowidWrite:parentWrite);
+  if( iHeight>0 ){
+    RtreeNode *pChild = nodeHashLookup(pRtree, iRowid);
+    RtreeNode *p;
+    for(p=pNode; p; p=p->pParent){
+      if( p==pChild ) return SQLITE_CORRUPT_VTAB;
+    }
+    if( pChild ){
+      nodeRelease(pRtree, pChild->pParent);
+      nodeReference(pNode);
+      pChild->pParent = pNode;
+    }
+  }
+  if( NEVER(pNode==0) ) return SQLITE_ERROR;
+  return xSetMapping(pRtree, iRowid, pNode->iNode);
+}
+
+static int SplitNode(
+  Rtree *pRtree,
+  RtreeNode *pNode,
+  RtreeCell *pCell,
+  int iHeight
+){
+  int i;
+  int newCellIsRight = 0;
+
+  int rc = SQLITE_OK;
+  int nCell = NCELL(pNode);
+  RtreeCell *aCell;
+  int *aiUsed;
+
+  RtreeNode *pLeft = 0;
+  RtreeNode *pRight = 0;
+
+  RtreeCell leftbbox;
+  RtreeCell rightbbox;
+
+  /* Allocate an array and populate it with a copy of pCell and
+  ** all cells from node pLeft. Then zero the original node.
+  */
+  aCell = sqlite3_malloc64((sizeof(RtreeCell)+sizeof(int))*(nCell+1));
+  if( !aCell ){
+    rc = SQLITE_NOMEM;
+    goto splitnode_out;
+  }
+  aiUsed = (int *)&aCell[nCell+1];
+  memset(aiUsed, 0, sizeof(int)*(nCell+1));
+  for(i=0; i<nCell; i++){
+    nodeGetCell(pRtree, pNode, i, &aCell[i]);
+  }
+  nodeZero(pRtree, pNode);
+  memcpy(&aCell[nCell], pCell, sizeof(RtreeCell));
+  nCell++;
+
+  if( pNode->iNode==1 ){
+    pRight = nodeNew(pRtree, pNode);
+    pLeft = nodeNew(pRtree, pNode);
+    pRtree->iDepth++;
+    pNode->isDirty = 1;
+    writeInt16(pNode->zData, pRtree->iDepth);
+  }else{
+    pLeft = pNode;
+    pRight = nodeNew(pRtree, pLeft->pParent);
+    pLeft->nRef++;
+  }
+
+  if( !pLeft || !pRight ){
+    rc = SQLITE_NOMEM;
+    goto splitnode_out;
+  }
+
+  memset(pLeft->zData, 0, pRtree->iNodeSize);
+  memset(pRight->zData, 0, pRtree->iNodeSize);
+
+  rc = splitNodeStartree(pRtree, aCell, nCell, pLeft, pRight,
+                         &leftbbox, &rightbbox);
+  if( rc!=SQLITE_OK ){
+    goto splitnode_out;
+  }
+
+  /* Ensure both child nodes have node numbers assigned to them by calling
+  ** nodeWrite(). Node pRight always needs a node number, as it was created
+  ** by nodeNew() above. But node pLeft sometimes already has a node number.
+  ** In this case avoid the all to nodeWrite().
+  */
+  if( SQLITE_OK!=(rc = nodeWrite(pRtree, pRight))
+   || (0==pLeft->iNode && SQLITE_OK!=(rc = nodeWrite(pRtree, pLeft)))
+  ){
+    goto splitnode_out;
+  }
+
+  rightbbox.iRowid = pRight->iNode;
+  leftbbox.iRowid = pLeft->iNode;
+
+  if( pNode->iNode==1 ){
+    rc = rtreeInsertCell(pRtree, pLeft->pParent, &leftbbox, iHeight+1);
+    if( rc!=SQLITE_OK ){
+      goto splitnode_out;
+    }
+  }else{
+    RtreeNode *pParent = pLeft->pParent;
+    int iCell;
+    rc = nodeParentIndex(pRtree, pLeft, &iCell);
+    if( ALWAYS(rc==SQLITE_OK) ){
+      nodeOverwriteCell(pRtree, pParent, &leftbbox, iCell);
+      rc = AdjustTree(pRtree, pParent, &leftbbox);
+      assert( rc==SQLITE_OK );
+    }
+    if( NEVER(rc!=SQLITE_OK) ){
+      goto splitnode_out;
+    }
+  }
+  if( (rc = rtreeInsertCell(pRtree, pRight->pParent, &rightbbox, iHeight+1)) ){
+    goto splitnode_out;
+  }
+
+  for(i=0; i<NCELL(pRight); i++){
+    i64 iRowid = nodeGetRowid(pRtree, pRight, i);
+    rc = updateMapping(pRtree, iRowid, pRight, iHeight);
+    if( iRowid==pCell->iRowid ){
+      newCellIsRight = 1;
+    }
+    if( rc!=SQLITE_OK ){
+      goto splitnode_out;
+    }
+  }
+  if( pNode->iNode==1 ){
+    for(i=0; i<NCELL(pLeft); i++){
+      i64 iRowid = nodeGetRowid(pRtree, pLeft, i);
+      rc = updateMapping(pRtree, iRowid, pLeft, iHeight);
+      if( rc!=SQLITE_OK ){
+        goto splitnode_out;
+      }
+    }
+  }else if( newCellIsRight==0 ){
+    rc = updateMapping(pRtree, pCell->iRowid, pLeft, iHeight);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = nodeRelease(pRtree, pRight);
+    pRight = 0;
+  }
+  if( rc==SQLITE_OK ){
+    rc = nodeRelease(pRtree, pLeft);
+    pLeft = 0;
+  }
+
+splitnode_out:
+  nodeRelease(pRtree, pRight);
+  nodeRelease(pRtree, pLeft);
+  sqlite3_free(aCell);
+  return rc;
+}
+
+/*
+** If node pLeaf is not the root of the r-tree and its pParent pointer is
+** still NULL, load all ancestor nodes of pLeaf into memory and populate
+** the pLeaf->pParent chain all the way up to the root node.
+**
+** This operation is required when a row is deleted (or updated - an update
+** is implemented as a delete followed by an insert). SQLite provides the
+** rowid of the row to delete, which can be used to find the leaf on which
+** the entry resides (argument pLeaf). Once the leaf is located, this
+** function is called to determine its ancestry.
+*/
+static int fixLeafParent(Rtree *pRtree, RtreeNode *pLeaf){
+  int rc = SQLITE_OK;
+  RtreeNode *pChild = pLeaf;
+  while( rc==SQLITE_OK && pChild->iNode!=1 && pChild->pParent==0 ){
+    int rc2 = SQLITE_OK;          /* sqlite3_reset() return code */
+    sqlite3_bind_int64(pRtree->pReadParent, 1, pChild->iNode);
+    rc = sqlite3_step(pRtree->pReadParent);
+    if( rc==SQLITE_ROW ){
+      RtreeNode *pTest;           /* Used to test for reference loops */
+      i64 iNode;                  /* Node number of parent node */
+
+      /* Before setting pChild->pParent, test that we are not creating a
+      ** loop of references (as we would if, say, pChild==pParent). We don't
+      ** want to do this as it leads to a memory leak when trying to delete
+      ** the referenced counted node structures.
+      */
+      iNode = sqlite3_column_int64(pRtree->pReadParent, 0);
+      for(pTest=pLeaf; pTest && pTest->iNode!=iNode; pTest=pTest->pParent);
+      if( pTest==0 ){
+        rc2 = nodeAcquire(pRtree, iNode, 0, &pChild->pParent);
+      }
+    }
+    rc = sqlite3_reset(pRtree->pReadParent);
+    if( rc==SQLITE_OK ) rc = rc2;
+    if( rc==SQLITE_OK && !pChild->pParent ){
+      RTREE_IS_CORRUPT(pRtree);
+      rc = SQLITE_CORRUPT_VTAB;
+    }
+    pChild = pChild->pParent;
+  }
+  return rc;
+}
+
+static int deleteCell(Rtree *, RtreeNode *, int, int);
+
+static int removeNode(Rtree *pRtree, RtreeNode *pNode, int iHeight){
+  int rc;
+  int rc2;
+  RtreeNode *pParent = 0;
+  int iCell;
+
+  assert( pNode->nRef==1 );
+
+  /* Remove the entry in the parent cell. */
+  rc = nodeParentIndex(pRtree, pNode, &iCell);
+  if( rc==SQLITE_OK ){
+    pParent = pNode->pParent;
+    pNode->pParent = 0;
+    rc = deleteCell(pRtree, pParent, iCell, iHeight+1);
+    testcase( rc!=SQLITE_OK );
+  }
+  rc2 = nodeRelease(pRtree, pParent);
+  if( rc==SQLITE_OK ){
+    rc = rc2;
+  }
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* Remove the xxx_node entry. */
+  sqlite3_bind_int64(pRtree->pDeleteNode, 1, pNode->iNode);
+  sqlite3_step(pRtree->pDeleteNode);
+  if( SQLITE_OK!=(rc = sqlite3_reset(pRtree->pDeleteNode)) ){
+    return rc;
+  }
+
+  /* Remove the xxx_parent entry. */
+  sqlite3_bind_int64(pRtree->pDeleteParent, 1, pNode->iNode);
+  sqlite3_step(pRtree->pDeleteParent);
+  if( SQLITE_OK!=(rc = sqlite3_reset(pRtree->pDeleteParent)) ){
+    return rc;
+  }
+
+  /* Remove the node from the in-memory hash table and link it into
+  ** the Rtree.pDeleted list. Its contents will be re-inserted later on.
+  */
+  nodeHashDelete(pRtree, pNode);
+  pNode->iNode = iHeight;
+  pNode->pNext = pRtree->pDeleted;
+  pNode->nRef++;
+  pRtree->pDeleted = pNode;
+
+  return SQLITE_OK;
+}
+
+static int fixBoundingBox(Rtree *pRtree, RtreeNode *pNode){
+  RtreeNode *pParent = pNode->pParent;
+  int rc = SQLITE_OK;
+  if( pParent ){
+    int ii;
+    int nCell = NCELL(pNode);
+    RtreeCell box;                            /* Bounding box for pNode */
+    nodeGetCell(pRtree, pNode, 0, &box);
+    for(ii=1; ii<nCell; ii++){
+      RtreeCell cell;
+      nodeGetCell(pRtree, pNode, ii, &cell);
+      cellUnion(pRtree, &box, &cell);
+    }
+    box.iRowid = pNode->iNode;
+    rc = nodeParentIndex(pRtree, pNode, &ii);
+    if( rc==SQLITE_OK ){
+      nodeOverwriteCell(pRtree, pParent, &box, ii);
+      rc = fixBoundingBox(pRtree, pParent);
+    }
+  }
+  return rc;
+}
+
+/*
+** Delete the cell at index iCell of node pNode. After removing the
+** cell, adjust the r-tree data structure if required.
+*/
+static int deleteCell(Rtree *pRtree, RtreeNode *pNode, int iCell, int iHeight){
+  RtreeNode *pParent;
+  int rc;
+
+  if( SQLITE_OK!=(rc = fixLeafParent(pRtree, pNode)) ){
+    return rc;
+  }
+
+  /* Remove the cell from the node. This call just moves bytes around
+  ** the in-memory node image, so it cannot fail.
+  */
+  nodeDeleteCell(pRtree, pNode, iCell);
+
+  /* If the node is not the tree root and now has less than the minimum
+  ** number of cells, remove it from the tree. Otherwise, update the
+  ** cell in the parent node so that it tightly contains the updated
+  ** node.
+  */
+  pParent = pNode->pParent;
+  assert( pParent || pNode->iNode==1 );
+  if( pParent ){
+    if( NCELL(pNode)<RTREE_MINCELLS(pRtree) ){
+      rc = removeNode(pRtree, pNode, iHeight);
+    }else{
+      rc = fixBoundingBox(pRtree, pNode);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Insert cell pCell into node pNode. Node pNode is the head of a
+** subtree iHeight high (leaf nodes have iHeight==0).
+*/
+static int rtreeInsertCell(
+  Rtree *pRtree,
+  RtreeNode *pNode,
+  RtreeCell *pCell,
+  int iHeight
+){
+  int rc = SQLITE_OK;
+  if( iHeight>0 ){
+    RtreeNode *pChild = nodeHashLookup(pRtree, pCell->iRowid);
+    if( pChild ){
+      nodeRelease(pRtree, pChild->pParent);
+      nodeReference(pNode);
+      pChild->pParent = pNode;
+    }
+  }
+  if( nodeInsertCell(pRtree, pNode, pCell) ){
+    rc = SplitNode(pRtree, pNode, pCell, iHeight);
+  }else{
+    rc = AdjustTree(pRtree, pNode, pCell);
+    if( ALWAYS(rc==SQLITE_OK) ){
+      if( iHeight==0 ){
+        rc = rowidWrite(pRtree, pCell->iRowid, pNode->iNode);
+      }else{
+        rc = parentWrite(pRtree, pCell->iRowid, pNode->iNode);
+      }
+    }
+  }
+  return rc;
+}
+
+static int reinsertNodeContent(Rtree *pRtree, RtreeNode *pNode){
+  int ii;
+  int rc = SQLITE_OK;
+  int nCell = NCELL(pNode);
+
+  for(ii=0; rc==SQLITE_OK && ii<nCell; ii++){
+    RtreeNode *pInsert;
+    RtreeCell cell;
+    nodeGetCell(pRtree, pNode, ii, &cell);
+
+    /* Find a node to store this cell in. pNode->iNode currently contains
+    ** the height of the sub-tree headed by the cell.
+    */
+    rc = ChooseLeaf(pRtree, &cell, (int)pNode->iNode, &pInsert);
+    if( rc==SQLITE_OK ){
+      int rc2;
+      rc = rtreeInsertCell(pRtree, pInsert, &cell, (int)pNode->iNode);
+      rc2 = nodeRelease(pRtree, pInsert);
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Select a currently unused rowid for a new r-tree record.
+*/
+static int rtreeNewRowid(Rtree *pRtree, i64 *piRowid){
+  int rc;
+  sqlite3_bind_null(pRtree->pWriteRowid, 1);
+  sqlite3_bind_null(pRtree->pWriteRowid, 2);
+  sqlite3_step(pRtree->pWriteRowid);
+  rc = sqlite3_reset(pRtree->pWriteRowid);
+  *piRowid = sqlite3_last_insert_rowid(pRtree->db);
+  return rc;
+}
+
+/*
+** Remove the entry with rowid=iDelete from the r-tree structure.
+*/
+static int rtreeDeleteRowid(Rtree *pRtree, sqlite3_int64 iDelete){
+  int rc;                         /* Return code */
+  RtreeNode *pLeaf = 0;           /* Leaf node containing record iDelete */
+  int iCell;                      /* Index of iDelete cell in pLeaf */
+  RtreeNode *pRoot = 0;           /* Root node of rtree structure */
+
+
+  /* Obtain a reference to the root node to initialize Rtree.iDepth */
+  rc = nodeAcquire(pRtree, 1, 0, &pRoot);
+
+  /* Obtain a reference to the leaf node that contains the entry
+  ** about to be deleted.
+  */
+  if( rc==SQLITE_OK ){
+    rc = findLeafNode(pRtree, iDelete, &pLeaf, 0);
+  }
+
+#ifdef CORRUPT_DB
+  assert( pLeaf!=0 || rc!=SQLITE_OK || CORRUPT_DB );
+#endif
+
+  /* Delete the cell in question from the leaf node. */
+  if( rc==SQLITE_OK && pLeaf ){
+    int rc2;
+    rc = nodeRowidIndex(pRtree, pLeaf, iDelete, &iCell);
+    if( rc==SQLITE_OK ){
+      rc = deleteCell(pRtree, pLeaf, iCell, 0);
+    }
+    rc2 = nodeRelease(pRtree, pLeaf);
+    if( rc==SQLITE_OK ){
+      rc = rc2;
+    }
+  }
+
+  /* Delete the corresponding entry in the <rtree>_rowid table. */
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pRtree->pDeleteRowid, 1, iDelete);
+    sqlite3_step(pRtree->pDeleteRowid);
+    rc = sqlite3_reset(pRtree->pDeleteRowid);
+  }
+
+  /* Check if the root node now has exactly one child. If so, remove
+  ** it, schedule the contents of the child for reinsertion and
+  ** reduce the tree height by one.
+  **
+  ** This is equivalent to copying the contents of the child into
+  ** the root node (the operation that Gutman's paper says to perform
+  ** in this scenario).
+  */
+  if( rc==SQLITE_OK && pRtree->iDepth>0 && NCELL(pRoot)==1 ){
+    int rc2;
+    RtreeNode *pChild = 0;
+    i64 iChild = nodeGetRowid(pRtree, pRoot, 0);
+    rc = nodeAcquire(pRtree, iChild, pRoot, &pChild);  /* tag-20210916a */
+    if( rc==SQLITE_OK ){
+      rc = removeNode(pRtree, pChild, pRtree->iDepth-1);
+    }
+    rc2 = nodeRelease(pRtree, pChild);
+    if( rc==SQLITE_OK ) rc = rc2;
+    if( rc==SQLITE_OK ){
+      pRtree->iDepth--;
+      writeInt16(pRoot->zData, pRtree->iDepth);
+      pRoot->isDirty = 1;
+    }
+  }
+
+  /* Re-insert the contents of any underfull nodes removed from the tree. */
+  for(pLeaf=pRtree->pDeleted; pLeaf; pLeaf=pRtree->pDeleted){
+    if( rc==SQLITE_OK ){
+      rc = reinsertNodeContent(pRtree, pLeaf);
+    }
+    pRtree->pDeleted = pLeaf->pNext;
+    pRtree->nNodeRef--;
+    sqlite3_free(pLeaf);
+  }
+
+  /* Release the reference to the root node. */
+  if( rc==SQLITE_OK ){
+    rc = nodeRelease(pRtree, pRoot);
+  }else{
+    nodeRelease(pRtree, pRoot);
+  }
+
+  return rc;
+}
+
+/*
+** Rounding constants for float->double conversion.
+*/
+#define RNDTOWARDS  (1.0 - 1.0/8388608.0)  /* Round towards zero */
+#define RNDAWAY     (1.0 + 1.0/8388608.0)  /* Round away from zero */
+
+#if !defined(SQLITE_RTREE_INT_ONLY)
+/*
+** Convert an sqlite3_value into an RtreeValue (presumably a float)
+** while taking care to round toward negative or positive, respectively.
+*/
+static RtreeValue rtreeValueDown(sqlite3_value *v){
+  double d = sqlite3_value_double(v);
+  float f = (float)d;
+  if( f>d ){
+    f = (float)(d*(d<0 ? RNDAWAY : RNDTOWARDS));
+  }
+  return f;
+}
+static RtreeValue rtreeValueUp(sqlite3_value *v){
+  double d = sqlite3_value_double(v);
+  float f = (float)d;
+  if( f<d ){
+    f = (float)(d*(d<0 ? RNDTOWARDS : RNDAWAY));
+  }
+  return f;
+}
+#endif /* !defined(SQLITE_RTREE_INT_ONLY) */
+
+/*
+** A constraint has failed while inserting a row into an rtree table.
+** Assuming no OOM error occurs, this function sets the error message
+** (at pRtree->base.zErrMsg) to an appropriate value and returns
+** SQLITE_CONSTRAINT.
+**
+** Parameter iCol is the index of the leftmost column involved in the
+** constraint failure. If it is 0, then the constraint that failed is
+** the unique constraint on the id column. Otherwise, it is the rtree
+** (c1<=c2) constraint on columns iCol and iCol+1 that has failed.
+**
+** If an OOM occurs, SQLITE_NOMEM is returned instead of SQLITE_CONSTRAINT.
+*/
+static int rtreeConstraintError(Rtree *pRtree, int iCol){
+  sqlite3_stmt *pStmt = 0;
+  char *zSql;
+  int rc;
+
+  assert( iCol==0 || iCol%2 );
+  zSql = sqlite3_mprintf("SELECT * FROM %Q.%Q", pRtree->zDb, pRtree->zName);
+  if( zSql ){
+    rc = sqlite3_prepare_v2(pRtree->db, zSql, -1, &pStmt, 0);
+  }else{
+    rc = SQLITE_NOMEM;
+  }
+  sqlite3_free(zSql);
+
+  if( rc==SQLITE_OK ){
+    if( iCol==0 ){
+      const char *zCol = sqlite3_column_name(pStmt, 0);
+      pRtree->base.zErrMsg = sqlite3_mprintf(
+          "UNIQUE constraint failed: %s.%s", pRtree->zName, zCol
+      );
+    }else{
+      const char *zCol1 = sqlite3_column_name(pStmt, iCol);
+      const char *zCol2 = sqlite3_column_name(pStmt, iCol+1);
+      pRtree->base.zErrMsg = sqlite3_mprintf(
+          "rtree constraint failed: %s.(%s<=%s)", pRtree->zName, zCol1, zCol2
+      );
+    }
+  }
+
+  sqlite3_finalize(pStmt);
+  return (rc==SQLITE_OK ? SQLITE_CONSTRAINT : rc);
+}
+
+
+
+/*
+** The xUpdate method for rtree module virtual tables.
+*/
+static int rtreeUpdate(
+  sqlite3_vtab *pVtab,
+  int nData,
+  sqlite3_value **aData,
+  sqlite_int64 *pRowid
+){
+  Rtree *pRtree = (Rtree *)pVtab;
+  int rc = SQLITE_OK;
+  RtreeCell cell;                 /* New cell to insert if nData>1 */
+  int bHaveRowid = 0;             /* Set to 1 after new rowid is determined */
+
+  if( pRtree->nNodeRef ){
+    /* Unable to write to the btree while another cursor is reading from it,
+    ** since the write might do a rebalance which would disrupt the read
+    ** cursor. */
+    return SQLITE_LOCKED_VTAB;
+  }
+  rtreeReference(pRtree);
+  assert(nData>=1);
+
+  memset(&cell, 0, sizeof(cell));
+
+  /* Constraint handling. A write operation on an r-tree table may return
+  ** SQLITE_CONSTRAINT for two reasons:
+  **
+  **   1. A duplicate rowid value, or
+  **   2. The supplied data violates the "x2>=x1" constraint.
+  **
+  ** In the first case, if the conflict-handling mode is REPLACE, then
+  ** the conflicting row can be removed before proceeding. In the second
+  ** case, SQLITE_CONSTRAINT must be returned regardless of the
+  ** conflict-handling mode specified by the user.
+  */
+  if( nData>1 ){
+    int ii;
+    int nn = nData - 4;
+
+    if( nn > pRtree->nDim2 ) nn = pRtree->nDim2;
+    /* Populate the cell.aCoord[] array. The first coordinate is aData[3].
+    **
+    ** NB: nData can only be less than nDim*2+3 if the rtree is mis-declared
+    ** with "column" that are interpreted as table constraints.
+    ** Example:  CREATE VIRTUAL TABLE bad USING rtree(x,y,CHECK(y>5));
+    ** This problem was discovered after years of use, so we silently ignore
+    ** these kinds of misdeclared tables to avoid breaking any legacy.
+    */
+
+#ifndef SQLITE_RTREE_INT_ONLY
+    if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+      for(ii=0; ii<nn; ii+=2){
+        cell.aCoord[ii].f = rtreeValueDown(aData[ii+3]);
+        cell.aCoord[ii+1].f = rtreeValueUp(aData[ii+4]);
+        if( cell.aCoord[ii].f>cell.aCoord[ii+1].f ){
+          rc = rtreeConstraintError(pRtree, ii+1);
+          goto constraint;
+        }
+      }
+    }else
+#endif
+    {
+      for(ii=0; ii<nn; ii+=2){
+        cell.aCoord[ii].i = sqlite3_value_int(aData[ii+3]);
+        cell.aCoord[ii+1].i = sqlite3_value_int(aData[ii+4]);
+        if( cell.aCoord[ii].i>cell.aCoord[ii+1].i ){
+          rc = rtreeConstraintError(pRtree, ii+1);
+          goto constraint;
+        }
+      }
+    }
+
+    /* If a rowid value was supplied, check if it is already present in
+    ** the table. If so, the constraint has failed. */
+    if( sqlite3_value_type(aData[2])!=SQLITE_NULL ){
+      cell.iRowid = sqlite3_value_int64(aData[2]);
+      if( sqlite3_value_type(aData[0])==SQLITE_NULL
+       || sqlite3_value_int64(aData[0])!=cell.iRowid
+      ){
+        int steprc;
+        sqlite3_bind_int64(pRtree->pReadRowid, 1, cell.iRowid);
+        steprc = sqlite3_step(pRtree->pReadRowid);
+        rc = sqlite3_reset(pRtree->pReadRowid);
+        if( SQLITE_ROW==steprc ){
+          if( sqlite3_vtab_on_conflict(pRtree->db)==SQLITE_REPLACE ){
+            rc = rtreeDeleteRowid(pRtree, cell.iRowid);
+          }else{
+            rc = rtreeConstraintError(pRtree, 0);
+            goto constraint;
+          }
+        }
+      }
+      bHaveRowid = 1;
+    }
+  }
+
+  /* If aData[0] is not an SQL NULL value, it is the rowid of a
+  ** record to delete from the r-tree table. The following block does
+  ** just that.
+  */
+  if( sqlite3_value_type(aData[0])!=SQLITE_NULL ){
+    rc = rtreeDeleteRowid(pRtree, sqlite3_value_int64(aData[0]));
+  }
+
+  /* If the aData[] array contains more than one element, elements
+  ** (aData[2]..aData[argc-1]) contain a new record to insert into
+  ** the r-tree structure.
+  */
+  if( rc==SQLITE_OK && nData>1 ){
+    /* Insert the new record into the r-tree */
+    RtreeNode *pLeaf = 0;
+
+    /* Figure out the rowid of the new row. */
+    if( bHaveRowid==0 ){
+      rc = rtreeNewRowid(pRtree, &cell.iRowid);
+    }
+    *pRowid = cell.iRowid;
+
+    if( rc==SQLITE_OK ){
+      rc = ChooseLeaf(pRtree, &cell, 0, &pLeaf);
+    }
+    if( rc==SQLITE_OK ){
+      int rc2;
+      rc = rtreeInsertCell(pRtree, pLeaf, &cell, 0);
+      rc2 = nodeRelease(pRtree, pLeaf);
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+    if( rc==SQLITE_OK && pRtree->nAux ){
+      sqlite3_stmt *pUp = pRtree->pWriteAux;
+      int jj;
+      sqlite3_bind_int64(pUp, 1, *pRowid);
+      for(jj=0; jj<pRtree->nAux; jj++){
+        sqlite3_bind_value(pUp, jj+2, aData[pRtree->nDim2+3+jj]);
+      }
+      sqlite3_step(pUp);
+      rc = sqlite3_reset(pUp);
+    }
+  }
+
+constraint:
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+/*
+** Called when a transaction starts.
+*/
+static int rtreeBeginTransaction(sqlite3_vtab *pVtab){
+  Rtree *pRtree = (Rtree *)pVtab;
+  assert( pRtree->inWrTrans==0 );
+  pRtree->inWrTrans = 1;
+  return SQLITE_OK;
+}
+
+/*
+** Called when a transaction completes (either by COMMIT or ROLLBACK).
+** The sqlite3_blob object should be released at this point.
+*/
+static int rtreeEndTransaction(sqlite3_vtab *pVtab){
+  Rtree *pRtree = (Rtree *)pVtab;
+  pRtree->inWrTrans = 0;
+  nodeBlobReset(pRtree);
+  return SQLITE_OK;
+}
+static int rtreeRollback(sqlite3_vtab *pVtab){
+  return rtreeEndTransaction(pVtab);
+}
+
+/*
+** The xRename method for rtree module virtual tables.
+*/
+static int rtreeRename(sqlite3_vtab *pVtab, const char *zNewName){
+  Rtree *pRtree = (Rtree *)pVtab;
+  int rc = SQLITE_NOMEM;
+  char *zSql = sqlite3_mprintf(
+    "ALTER TABLE %Q.'%q_node'   RENAME TO \"%w_node\";"
+    "ALTER TABLE %Q.'%q_parent' RENAME TO \"%w_parent\";"
+    "ALTER TABLE %Q.'%q_rowid'  RENAME TO \"%w_rowid\";"
+    , pRtree->zDb, pRtree->zName, zNewName
+    , pRtree->zDb, pRtree->zName, zNewName
+    , pRtree->zDb, pRtree->zName, zNewName
+  );
+  if( zSql ){
+    nodeBlobReset(pRtree);
+    rc = sqlite3_exec(pRtree->db, zSql, 0, 0, 0);
+    sqlite3_free(zSql);
+  }
+  return rc;
+}
+
+/*
+** The xSavepoint method.
+**
+** This module does not need to do anything to support savepoints. However,
+** it uses this hook to close any open blob handle. This is done because a
+** DROP TABLE command - which fortunately always opens a savepoint - cannot
+** succeed if there are any open blob handles. i.e. if the blob handle were
+** not closed here, the following would fail:
+**
+**   BEGIN;
+**     INSERT INTO rtree...
+**     DROP TABLE <tablename>;    -- Would fail with SQLITE_LOCKED
+**   COMMIT;
+*/
+static int rtreeSavepoint(sqlite3_vtab *pVtab, int iSavepoint){
+  Rtree *pRtree = (Rtree *)pVtab;
+  u8 iwt = pRtree->inWrTrans;
+  UNUSED_PARAMETER(iSavepoint);
+  pRtree->inWrTrans = 0;
+  nodeBlobReset(pRtree);
+  pRtree->inWrTrans = iwt;
+  return SQLITE_OK;
+}
+
+/*
+** This function populates the pRtree->nRowEst variable with an estimate
+** of the number of rows in the virtual table. If possible, this is based
+** on sqlite_stat1 data. Otherwise, use RTREE_DEFAULT_ROWEST.
+*/
+static int rtreeQueryStat1(sqlite3 *db, Rtree *pRtree){
+  const char *zFmt = "SELECT stat FROM %Q.sqlite_stat1 WHERE tbl = '%q_rowid'";
+  char *zSql;
+  sqlite3_stmt *p;
+  int rc;
+  i64 nRow = RTREE_MIN_ROWEST;
+
+  rc = sqlite3_table_column_metadata(
+      db, pRtree->zDb, "sqlite_stat1",0,0,0,0,0,0
+  );
+  if( rc!=SQLITE_OK ){
+    pRtree->nRowEst = RTREE_DEFAULT_ROWEST;
+    return rc==SQLITE_ERROR ? SQLITE_OK : rc;
+  }
+  zSql = sqlite3_mprintf(zFmt, pRtree->zDb, pRtree->zName);
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare_v2(db, zSql, -1, &p, 0);
+    if( rc==SQLITE_OK ){
+      if( sqlite3_step(p)==SQLITE_ROW ) nRow = sqlite3_column_int64(p, 0);
+      rc = sqlite3_finalize(p);
+    }
+    sqlite3_free(zSql);
+  }
+  pRtree->nRowEst = MAX(nRow, RTREE_MIN_ROWEST);
+  return rc;
+}
+
+
+/*
+** Return true if zName is the extension on one of the shadow tables used
+** by this module.
+*/
+static int rtreeShadowName(const char *zName){
+  static const char *azName[] = {
+    "node", "parent", "rowid"
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
+    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
+  }
+  return 0;
+}
+
+/* Forward declaration */
+static int rtreeIntegrity(sqlite3_vtab*, const char*, const char*, int, char**);
+
+static sqlite3_module rtreeModule = {
+  4,                          /* iVersion */
+  rtreeCreate,                /* xCreate - create a table */
+  rtreeConnect,               /* xConnect - connect to an existing table */
+  rtreeBestIndex,             /* xBestIndex - Determine search strategy */
+  rtreeDisconnect,            /* xDisconnect - Disconnect from a table */
+  rtreeDestroy,               /* xDestroy - Drop a table */
+  rtreeOpen,                  /* xOpen - open a cursor */
+  rtreeClose,                 /* xClose - close a cursor */
+  rtreeFilter,                /* xFilter - configure scan constraints */
+  rtreeNext,                  /* xNext - advance a cursor */
+  rtreeEof,                   /* xEof */
+  rtreeColumn,                /* xColumn - read data */
+  rtreeRowid,                 /* xRowid - read data */
+  rtreeUpdate,                /* xUpdate - write data */
+  rtreeBeginTransaction,      /* xBegin - begin transaction */
+  rtreeEndTransaction,        /* xSync - sync transaction */
+  rtreeEndTransaction,        /* xCommit - commit transaction */
+  rtreeRollback,              /* xRollback - rollback transaction */
+  0,                          /* xFindFunction - function overloading */
+  rtreeRename,                /* xRename - rename the table */
+  rtreeSavepoint,             /* xSavepoint */
+  0,                          /* xRelease */
+  0,                          /* xRollbackTo */
+  rtreeShadowName,            /* xShadowName */
+  rtreeIntegrity              /* xIntegrity */
+};
+
+static int rtreeSqlInit(
+  Rtree *pRtree,
+  sqlite3 *db,
+  const char *zDb,
+  const char *zPrefix,
+  int isCreate
+){
+  int rc = SQLITE_OK;
+
+  #define N_STATEMENT 8
+  static const char *azSql[N_STATEMENT] = {
+    /* Write the xxx_node table */
+    "INSERT OR REPLACE INTO '%q'.'%q_node' VALUES(?1, ?2)",
+    "DELETE FROM '%q'.'%q_node' WHERE nodeno = ?1",
+
+    /* Read and write the xxx_rowid table */
+    "SELECT nodeno FROM '%q'.'%q_rowid' WHERE rowid = ?1",
+    "INSERT OR REPLACE INTO '%q'.'%q_rowid' VALUES(?1, ?2)",
+    "DELETE FROM '%q'.'%q_rowid' WHERE rowid = ?1",
+
+    /* Read and write the xxx_parent table */
+    "SELECT parentnode FROM '%q'.'%q_parent' WHERE nodeno = ?1",
+    "INSERT OR REPLACE INTO '%q'.'%q_parent' VALUES(?1, ?2)",
+    "DELETE FROM '%q'.'%q_parent' WHERE nodeno = ?1"
+  };
+  sqlite3_stmt **appStmt[N_STATEMENT];
+  int i;
+  const int f = SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB;
+
+  pRtree->db = db;
+
+  if( isCreate ){
+    char *zCreate;
+    sqlite3_str *p = sqlite3_str_new(db);
+    int ii;
+    sqlite3_str_appendf(p,
+       "CREATE TABLE \"%w\".\"%w_rowid\"(rowid INTEGER PRIMARY KEY,nodeno",
+       zDb, zPrefix);
+    for(ii=0; ii<pRtree->nAux; ii++){
+      sqlite3_str_appendf(p,",a%d",ii);
+    }
+    sqlite3_str_appendf(p,
+      ");CREATE TABLE \"%w\".\"%w_node\"(nodeno INTEGER PRIMARY KEY,data);",
+      zDb, zPrefix);
+    sqlite3_str_appendf(p,
+    "CREATE TABLE \"%w\".\"%w_parent\"(nodeno INTEGER PRIMARY KEY,parentnode);",
+      zDb, zPrefix);
+    sqlite3_str_appendf(p,
+       "INSERT INTO \"%w\".\"%w_node\"VALUES(1,zeroblob(%d))",
+       zDb, zPrefix, pRtree->iNodeSize);
+    zCreate = sqlite3_str_finish(p);
+    if( !zCreate ){
+      return SQLITE_NOMEM;
+    }
+    rc = sqlite3_exec(db, zCreate, 0, 0, 0);
+    sqlite3_free(zCreate);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+  }
+
+  appStmt[0] = &pRtree->pWriteNode;
+  appStmt[1] = &pRtree->pDeleteNode;
+  appStmt[2] = &pRtree->pReadRowid;
+  appStmt[3] = &pRtree->pWriteRowid;
+  appStmt[4] = &pRtree->pDeleteRowid;
+  appStmt[5] = &pRtree->pReadParent;
+  appStmt[6] = &pRtree->pWriteParent;
+  appStmt[7] = &pRtree->pDeleteParent;
+
+  rc = rtreeQueryStat1(db, pRtree);
+  for(i=0; i<N_STATEMENT && rc==SQLITE_OK; i++){
+    char *zSql;
+    const char *zFormat;
+    if( i!=3 || pRtree->nAux==0 ){
+       zFormat = azSql[i];
+    }else {
+       /* An UPSERT is very slightly slower than REPLACE, but it is needed
+       ** if there are auxiliary columns */
+       zFormat = "INSERT INTO\"%w\".\"%w_rowid\"(rowid,nodeno)VALUES(?1,?2)"
+                  "ON CONFLICT(rowid)DO UPDATE SET nodeno=excluded.nodeno";
+    }
+    zSql = sqlite3_mprintf(zFormat, zDb, zPrefix);
+    if( zSql ){
+      rc = sqlite3_prepare_v3(db, zSql, -1, f, appStmt[i], 0);
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+    sqlite3_free(zSql);
+  }
+  if( pRtree->nAux && rc!=SQLITE_NOMEM ){
+    pRtree->zReadAuxSql = sqlite3_mprintf(
+       "SELECT * FROM \"%w\".\"%w_rowid\" WHERE rowid=?1",
+       zDb, zPrefix);
+    if( pRtree->zReadAuxSql==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      sqlite3_str *p = sqlite3_str_new(db);
+      int ii;
+      char *zSql;
+      sqlite3_str_appendf(p, "UPDATE \"%w\".\"%w_rowid\"SET ", zDb, zPrefix);
+      for(ii=0; ii<pRtree->nAux; ii++){
+        if( ii ) sqlite3_str_append(p, ",", 1);
+#ifdef SQLITE_ENABLE_GEOPOLY
+        if( ii<pRtree->nAuxNotNull ){
+          sqlite3_str_appendf(p,"a%d=coalesce(?%d,a%d)",ii,ii+2,ii);
+        }else
+#endif
+        {
+          sqlite3_str_appendf(p,"a%d=?%d",ii,ii+2);
+        }
+      }
+      sqlite3_str_appendf(p, " WHERE rowid=?1");
+      zSql = sqlite3_str_finish(p);
+      if( zSql==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        rc = sqlite3_prepare_v3(db, zSql, -1, f, &pRtree->pWriteAux, 0);
+        sqlite3_free(zSql);
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The second argument to this function contains the text of an SQL statement
+** that returns a single integer value. The statement is compiled and executed
+** using database connection db. If successful, the integer value returned
+** is written to *piVal and SQLITE_OK returned. Otherwise, an SQLite error
+** code is returned and the value of *piVal after returning is not defined.
+*/
+static int getIntFromStmt(sqlite3 *db, const char *zSql, int *piVal){
+  int rc = SQLITE_NOMEM;
+  if( zSql ){
+    sqlite3_stmt *pStmt = 0;
+    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        *piVal = sqlite3_column_int(pStmt, 0);
+      }
+      rc = sqlite3_finalize(pStmt);
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is called from within the xConnect() or xCreate() method to
+** determine the node-size used by the rtree table being created or connected
+** to. If successful, pRtree->iNodeSize is populated and SQLITE_OK returned.
+** Otherwise, an SQLite error code is returned.
+**
+** If this function is being called as part of an xConnect(), then the rtree
+** table already exists. In this case the node-size is determined by inspecting
+** the root node of the tree.
+**
+** Otherwise, for an xCreate(), use 64 bytes less than the database page-size.
+** This ensures that each node is stored on a single database page. If the
+** database page-size is so large that more than RTREE_MAXCELLS entries
+** would fit in a single node, use a smaller node-size.
+*/
+static int getNodeSize(
+  sqlite3 *db,                    /* Database handle */
+  Rtree *pRtree,                  /* Rtree handle */
+  int isCreate,                   /* True for xCreate, false for xConnect */
+  char **pzErr                    /* OUT: Error message, if any */
+){
+  int rc;
+  char *zSql;
+  if( isCreate ){
+    int iPageSize = 0;
+    zSql = sqlite3_mprintf("PRAGMA %Q.page_size", pRtree->zDb);
+    rc = getIntFromStmt(db, zSql, &iPageSize);
+    if( rc==SQLITE_OK ){
+      pRtree->iNodeSize = iPageSize-64;
+      if( (4+pRtree->nBytesPerCell*RTREE_MAXCELLS)<pRtree->iNodeSize ){
+        pRtree->iNodeSize = 4+pRtree->nBytesPerCell*RTREE_MAXCELLS;
+      }
+    }else{
+      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    }
+  }else{
+    zSql = sqlite3_mprintf(
+        "SELECT length(data) FROM '%q'.'%q_node' WHERE nodeno = 1",
+        pRtree->zDb, pRtree->zName
+    );
+    rc = getIntFromStmt(db, zSql, &pRtree->iNodeSize);
+    if( rc!=SQLITE_OK ){
+      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    }else if( pRtree->iNodeSize<(512-64) ){
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+      *pzErr = sqlite3_mprintf("undersize RTree blobs in \"%q_node\"",
+                               pRtree->zName);
+    }
+  }
+
+  sqlite3_free(zSql);
+  return rc;
+}
+
+/*
+** Return the length of a token
+*/
+static int rtreeTokenLength(const char *z){
+  int dummy = 0;
+  return sqlite3GetToken((const unsigned char*)z,&dummy);
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the r-tree virtual table.
+**
+**   argv[0]   -> module name
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> column names...
+*/
+static int rtreeInit(
+  sqlite3 *db,                        /* Database connection */
+  void *pAux,                         /* One of the RTREE_COORD_* constants */
+  int argc, const char *const*argv,   /* Parameters to CREATE TABLE statement */
+  sqlite3_vtab **ppVtab,              /* OUT: New virtual table */
+  char **pzErr,                       /* OUT: Error message, if any */
+  int isCreate                        /* True for xCreate, false for xConnect */
+){
+  int rc = SQLITE_OK;
+  Rtree *pRtree;
+  int nDb;              /* Length of string argv[1] */
+  int nName;            /* Length of string argv[2] */
+  int eCoordType = (pAux ? RTREE_COORD_INT32 : RTREE_COORD_REAL32);
+  sqlite3_str *pSql;
+  char *zSql;
+  int ii = 4;
+  int iErr;
+
+  const char *aErrMsg[] = {
+    0,                                                    /* 0 */
+    "Wrong number of columns for an rtree table",         /* 1 */
+    "Too few columns for an rtree table",                 /* 2 */
+    "Too many columns for an rtree table",                /* 3 */
+    "Auxiliary rtree columns must be last"                /* 4 */
+  };
+
+  assert( RTREE_MAX_AUX_COLUMN<256 ); /* Aux columns counted by a u8 */
+  if( argc<6 || argc>RTREE_MAX_AUX_COLUMN+3 ){
+    *pzErr = sqlite3_mprintf("%s", aErrMsg[2 + (argc>=6)]);
+    return SQLITE_ERROR;
+  }
+
+  sqlite3_vtab_config(db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1);
+  sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
+
+
+  /* Allocate the sqlite3_vtab structure */
+  nDb = (int)strlen(argv[1]);
+  nName = (int)strlen(argv[2]);
+  pRtree = (Rtree *)sqlite3_malloc64(sizeof(Rtree)+nDb+nName*2+8);
+  if( !pRtree ){
+    return SQLITE_NOMEM;
+  }
+  memset(pRtree, 0, sizeof(Rtree)+nDb+nName*2+8);
+  pRtree->nBusy = 1;
+  pRtree->base.pModule = &rtreeModule;
+  pRtree->zDb = (char *)&pRtree[1];
+  pRtree->zName = &pRtree->zDb[nDb+1];
+  pRtree->zNodeName = &pRtree->zName[nName+1];
+  pRtree->eCoordType = (u8)eCoordType;
+  memcpy(pRtree->zDb, argv[1], nDb);
+  memcpy(pRtree->zName, argv[2], nName);
+  memcpy(pRtree->zNodeName, argv[2], nName);
+  memcpy(&pRtree->zNodeName[nName], "_node", 6);
+
+
+  /* Create/Connect to the underlying relational database schema. If
+  ** that is successful, call sqlite3_declare_vtab() to configure
+  ** the r-tree table schema.
+  */
+  pSql = sqlite3_str_new(db);
+  sqlite3_str_appendf(pSql, "CREATE TABLE x(%.*s INT",
+                      rtreeTokenLength(argv[3]), argv[3]);
+  for(ii=4; ii<argc; ii++){
+    const char *zArg = argv[ii];
+    if( zArg[0]=='+' ){
+      pRtree->nAux++;
+      sqlite3_str_appendf(pSql, ",%.*s", rtreeTokenLength(zArg+1), zArg+1);
+    }else if( pRtree->nAux>0 ){
+      break;
+    }else{
+      static const char *azFormat[] = {",%.*s REAL", ",%.*s INT"};
+      pRtree->nDim2++;
+      sqlite3_str_appendf(pSql, azFormat[eCoordType],
+                          rtreeTokenLength(zArg), zArg);
+    }
+  }
+  sqlite3_str_appendf(pSql, ");");
+  zSql = sqlite3_str_finish(pSql);
+  if( !zSql ){
+    rc = SQLITE_NOMEM;
+  }else if( ii<argc ){
+    *pzErr = sqlite3_mprintf("%s", aErrMsg[4]);
+    rc = SQLITE_ERROR;
+  }else if( SQLITE_OK!=(rc = sqlite3_declare_vtab(db, zSql)) ){
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+  }
+  sqlite3_free(zSql);
+  if( rc ) goto rtreeInit_fail;
+  pRtree->nDim = pRtree->nDim2/2;
+  if( pRtree->nDim<1 ){
+    iErr = 2;
+  }else if( pRtree->nDim2>RTREE_MAX_DIMENSIONS*2 ){
+    iErr = 3;
+  }else if( pRtree->nDim2 % 2 ){
+    iErr = 1;
+  }else{
+    iErr = 0;
+  }
+  if( iErr ){
+    *pzErr = sqlite3_mprintf("%s", aErrMsg[iErr]);
+    goto rtreeInit_fail;
+  }
+  pRtree->nBytesPerCell = 8 + pRtree->nDim2*4;
+
+  /* Figure out the node size to use. */
+  rc = getNodeSize(db, pRtree, isCreate, pzErr);
+  if( rc ) goto rtreeInit_fail;
+  rc = rtreeSqlInit(pRtree, db, argv[1], argv[2], isCreate);
+  if( rc ){
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    goto rtreeInit_fail;
+  }
+
+  *ppVtab = (sqlite3_vtab *)pRtree;
+  return SQLITE_OK;
+
+rtreeInit_fail:
+  if( rc==SQLITE_OK ) rc = SQLITE_ERROR;
+  assert( *ppVtab==0 );
+  assert( pRtree->nBusy==1 );
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+
+/*
+** Implementation of a scalar function that decodes r-tree nodes to
+** human readable strings. This can be used for debugging and analysis.
+**
+** The scalar function takes two arguments: (1) the number of dimensions
+** to the rtree (between 1 and 5, inclusive) and (2) a blob of data containing
+** an r-tree node.  For a two-dimensional r-tree structure called "rt", to
+** deserialize all nodes, a statement like:
+**
+**   SELECT rtreenode(2, data) FROM rt_node;
+**
+** The human readable string takes the form of a Tcl list with one
+** entry for each cell in the r-tree node. Each entry is itself a
+** list, containing the 8-byte rowid/pageno followed by the
+** <num-dimension>*2 coordinates.
+*/
+static void rtreenode(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
+  RtreeNode node;
+  Rtree tree;
+  int ii;
+  int nData;
+  int errCode;
+  sqlite3_str *pOut;
+
+  UNUSED_PARAMETER(nArg);
+  memset(&node, 0, sizeof(RtreeNode));
+  memset(&tree, 0, sizeof(Rtree));
+  tree.nDim = (u8)sqlite3_value_int(apArg[0]);
+  if( tree.nDim<1 || tree.nDim>5 ) return;
+  tree.nDim2 = tree.nDim*2;
+  tree.nBytesPerCell = 8 + 8 * tree.nDim;
+  node.zData = (u8 *)sqlite3_value_blob(apArg[1]);
+  if( node.zData==0 ) return;
+  nData = sqlite3_value_bytes(apArg[1]);
+  if( nData<4 ) return;
+  if( nData<NCELL(&node)*tree.nBytesPerCell ) return;
+
+  pOut = sqlite3_str_new(0);
+  for(ii=0; ii<NCELL(&node); ii++){
+    RtreeCell cell;
+    int jj;
+
+    nodeGetCell(&tree, &node, ii, &cell);
+    if( ii>0 ) sqlite3_str_append(pOut, " ", 1);
+    sqlite3_str_appendf(pOut, "{%lld", cell.iRowid);
+    for(jj=0; jj<tree.nDim2; jj++){
+#ifndef SQLITE_RTREE_INT_ONLY
+      sqlite3_str_appendf(pOut, " %g", (double)cell.aCoord[jj].f);
+#else
+      sqlite3_str_appendf(pOut, " %d", cell.aCoord[jj].i);
+#endif
+    }
+    sqlite3_str_append(pOut, "}", 1);
+  }
+  errCode = sqlite3_str_errcode(pOut);
+  sqlite3_result_error_code(ctx, errCode);
+  sqlite3_result_text(ctx, sqlite3_str_finish(pOut), -1, sqlite3_free);
+}
+
+/* This routine implements an SQL function that returns the "depth" parameter
+** from the front of a blob that is an r-tree node.  For example:
+**
+**     SELECT rtreedepth(data) FROM rt_node WHERE nodeno=1;
+**
+** The depth value is 0 for all nodes other than the root node, and the root
+** node always has nodeno=1, so the example above is the primary use for this
+** routine.  This routine is intended for testing and analysis only.
+*/
+static void rtreedepth(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
+  UNUSED_PARAMETER(nArg);
+  if( sqlite3_value_type(apArg[0])!=SQLITE_BLOB
+   || sqlite3_value_bytes(apArg[0])<2
+
+  ){
+    sqlite3_result_error(ctx, "Invalid argument to rtreedepth()", -1);
+  }else{
+    u8 *zBlob = (u8 *)sqlite3_value_blob(apArg[0]);
+    if( zBlob ){
+      sqlite3_result_int(ctx, readInt16(zBlob));
+    }else{
+      sqlite3_result_error_nomem(ctx);
+    }
+  }
+}
+
+/*
+** Context object passed between the various routines that make up the
+** implementation of integrity-check function rtreecheck().
+*/
+typedef struct RtreeCheck RtreeCheck;
+struct RtreeCheck {
+  sqlite3 *db;                    /* Database handle */
+  const char *zDb;                /* Database containing rtree table */
+  const char *zTab;               /* Name of rtree table */
+  int bInt;                       /* True for rtree_i32 table */
+  int nDim;                       /* Number of dimensions for this rtree tbl */
+  sqlite3_stmt *pGetNode;         /* Statement used to retrieve nodes */
+  sqlite3_stmt *aCheckMapping[2]; /* Statements to query %_parent/%_rowid */
+  int nLeaf;                      /* Number of leaf cells in table */
+  int nNonLeaf;                   /* Number of non-leaf cells in table */
+  int rc;                         /* Return code */
+  char *zReport;                  /* Message to report */
+  int nErr;                       /* Number of lines in zReport */
+};
+
+#define RTREE_CHECK_MAX_ERROR 100
+
+/*
+** Reset SQL statement pStmt. If the sqlite3_reset() call returns an error,
+** and RtreeCheck.rc==SQLITE_OK, set RtreeCheck.rc to the error code.
+*/
+static void rtreeCheckReset(RtreeCheck *pCheck, sqlite3_stmt *pStmt){
+  int rc = sqlite3_reset(pStmt);
+  if( pCheck->rc==SQLITE_OK ) pCheck->rc = rc;
+}
+
+/*
+** The second and subsequent arguments to this function are a format string
+** and printf style arguments. This function formats the string and attempts
+** to compile it as an SQL statement.
+**
+** If successful, a pointer to the new SQL statement is returned. Otherwise,
+** NULL is returned and an error code left in RtreeCheck.rc.
+*/
+static sqlite3_stmt *rtreeCheckPrepare(
+  RtreeCheck *pCheck,             /* RtreeCheck object */
+  const char *zFmt, ...           /* Format string and trailing args */
+){
+  va_list ap;
+  char *z;
+  sqlite3_stmt *pRet = 0;
+
+  va_start(ap, zFmt);
+  z = sqlite3_vmprintf(zFmt, ap);
+
+  if( pCheck->rc==SQLITE_OK ){
+    if( z==0 ){
+      pCheck->rc = SQLITE_NOMEM;
+    }else{
+      pCheck->rc = sqlite3_prepare_v2(pCheck->db, z, -1, &pRet, 0);
+    }
+  }
+
+  sqlite3_free(z);
+  va_end(ap);
+  return pRet;
+}
+
+/*
+** The second and subsequent arguments to this function are a printf()
+** style format string and arguments. This function formats the string and
+** appends it to the report being accumuated in pCheck.
+*/
+static void rtreeCheckAppendMsg(RtreeCheck *pCheck, const char *zFmt, ...){
+  va_list ap;
+  va_start(ap, zFmt);
+  if( pCheck->rc==SQLITE_OK && pCheck->nErr<RTREE_CHECK_MAX_ERROR ){
+    char *z = sqlite3_vmprintf(zFmt, ap);
+    if( z==0 ){
+      pCheck->rc = SQLITE_NOMEM;
+    }else{
+      pCheck->zReport = sqlite3_mprintf("%z%s%z",
+          pCheck->zReport, (pCheck->zReport ? "\n" : ""), z
+      );
+      if( pCheck->zReport==0 ){
+        pCheck->rc = SQLITE_NOMEM;
+      }
+    }
+    pCheck->nErr++;
+  }
+  va_end(ap);
+}
+
+/*
+** This function is a no-op if there is already an error code stored
+** in the RtreeCheck object indicated by the first argument. NULL is
+** returned in this case.
+**
+** Otherwise, the contents of rtree table node iNode are loaded from
+** the database and copied into a buffer obtained from sqlite3_malloc().
+** If no error occurs, a pointer to the buffer is returned and (*pnNode)
+** is set to the size of the buffer in bytes.
+**
+** Or, if an error does occur, NULL is returned and an error code left
+** in the RtreeCheck object. The final value of *pnNode is undefined in
+** this case.
+*/
+static u8 *rtreeCheckGetNode(RtreeCheck *pCheck, i64 iNode, int *pnNode){
+  u8 *pRet = 0;                   /* Return value */
+
+  if( pCheck->rc==SQLITE_OK && pCheck->pGetNode==0 ){
+    pCheck->pGetNode = rtreeCheckPrepare(pCheck,
+        "SELECT data FROM %Q.'%q_node' WHERE nodeno=?",
+        pCheck->zDb, pCheck->zTab
+    );
+  }
+
+  if( pCheck->rc==SQLITE_OK ){
+    sqlite3_bind_int64(pCheck->pGetNode, 1, iNode);
+    if( sqlite3_step(pCheck->pGetNode)==SQLITE_ROW ){
+      int nNode = sqlite3_column_bytes(pCheck->pGetNode, 0);
+      const u8 *pNode = (const u8*)sqlite3_column_blob(pCheck->pGetNode, 0);
+      pRet = sqlite3_malloc64(nNode);
+      if( pRet==0 ){
+        pCheck->rc = SQLITE_NOMEM;
+      }else{
+        memcpy(pRet, pNode, nNode);
+        *pnNode = nNode;
+      }
+    }
+    rtreeCheckReset(pCheck, pCheck->pGetNode);
+    if( pCheck->rc==SQLITE_OK && pRet==0 ){
+      rtreeCheckAppendMsg(pCheck, "Node %lld missing from database", iNode);
+    }
+  }
+
+  return pRet;
+}
+
+/*
+** This function is used to check that the %_parent (if bLeaf==0) or %_rowid
+** (if bLeaf==1) table contains a specified entry. The schemas of the
+** two tables are:
+**
+**   CREATE TABLE %_parent(nodeno INTEGER PRIMARY KEY, parentnode INTEGER)
+**   CREATE TABLE %_rowid(rowid INTEGER PRIMARY KEY, nodeno INTEGER, ...)
+**
+** In both cases, this function checks that there exists an entry with
+** IPK value iKey and the second column set to iVal.
+**
+*/
+static void rtreeCheckMapping(
+  RtreeCheck *pCheck,             /* RtreeCheck object */
+  int bLeaf,                      /* True for a leaf cell, false for interior */
+  i64 iKey,                       /* Key for mapping */
+  i64 iVal                        /* Expected value for mapping */
+){
+  int rc;
+  sqlite3_stmt *pStmt;
+  const char *azSql[2] = {
+    "SELECT parentnode FROM %Q.'%q_parent' WHERE nodeno=?1",
+    "SELECT nodeno FROM %Q.'%q_rowid' WHERE rowid=?1"
+  };
+
+  assert( bLeaf==0 || bLeaf==1 );
+  if( pCheck->aCheckMapping[bLeaf]==0 ){
+    pCheck->aCheckMapping[bLeaf] = rtreeCheckPrepare(pCheck,
+        azSql[bLeaf], pCheck->zDb, pCheck->zTab
+    );
+  }
+  if( pCheck->rc!=SQLITE_OK ) return;
+
+  pStmt = pCheck->aCheckMapping[bLeaf];
+  sqlite3_bind_int64(pStmt, 1, iKey);
+  rc = sqlite3_step(pStmt);
+  if( rc==SQLITE_DONE ){
+    rtreeCheckAppendMsg(pCheck, "Mapping (%lld -> %lld) missing from %s table",
+        iKey, iVal, (bLeaf ? "%_rowid" : "%_parent")
+    );
+  }else if( rc==SQLITE_ROW ){
+    i64 ii = sqlite3_column_int64(pStmt, 0);
+    if( ii!=iVal ){
+      rtreeCheckAppendMsg(pCheck,
+          "Found (%lld -> %lld) in %s table, expected (%lld -> %lld)",
+          iKey, ii, (bLeaf ? "%_rowid" : "%_parent"), iKey, iVal
+      );
+    }
+  }
+  rtreeCheckReset(pCheck, pStmt);
+}
+
+/*
+** Argument pCell points to an array of coordinates stored on an rtree page.
+** This function checks that the coordinates are internally consistent (no
+** x1>x2 conditions) and adds an error message to the RtreeCheck object
+** if they are not.
+**
+** Additionally, if pParent is not NULL, then it is assumed to point to
+** the array of coordinates on the parent page that bound the page
+** containing pCell. In this case it is also verified that the two
+** sets of coordinates are mutually consistent and an error message added
+** to the RtreeCheck object if they are not.
+*/
+static void rtreeCheckCellCoord(
+  RtreeCheck *pCheck,
+  i64 iNode,                      /* Node id to use in error messages */
+  int iCell,                      /* Cell number to use in error messages */
+  u8 *pCell,                      /* Pointer to cell coordinates */
+  u8 *pParent                     /* Pointer to parent coordinates */
+){
+  RtreeCoord c1, c2;
+  RtreeCoord p1, p2;
+  int i;
+
+  for(i=0; i<pCheck->nDim; i++){
+    readCoord(&pCell[4*2*i], &c1);
+    readCoord(&pCell[4*(2*i + 1)], &c2);
+
+    /* printf("%e, %e\n", c1.u.f, c2.u.f); */
+    if( pCheck->bInt ? c1.i>c2.i : c1.f>c2.f ){
+      rtreeCheckAppendMsg(pCheck,
+          "Dimension %d of cell %d on node %lld is corrupt", i, iCell, iNode
+      );
+    }
+
+    if( pParent ){
+      readCoord(&pParent[4*2*i], &p1);
+      readCoord(&pParent[4*(2*i + 1)], &p2);
+
+      if( (pCheck->bInt ? c1.i<p1.i : c1.f<p1.f)
+       || (pCheck->bInt ? c2.i>p2.i : c2.f>p2.f)
+      ){
+        rtreeCheckAppendMsg(pCheck,
+            "Dimension %d of cell %d on node %lld is corrupt relative to parent"
+            , i, iCell, iNode
+        );
+      }
+    }
+  }
+}
+
+/*
+** Run rtreecheck() checks on node iNode, which is at depth iDepth within
+** the r-tree structure. Argument aParent points to the array of coordinates
+** that bound node iNode on the parent node.
+**
+** If any problems are discovered, an error message is appended to the
+** report accumulated in the RtreeCheck object.
+*/
+static void rtreeCheckNode(
+  RtreeCheck *pCheck,
+  int iDepth,                     /* Depth of iNode (0==leaf) */
+  u8 *aParent,                    /* Buffer containing parent coords */
+  i64 iNode                       /* Node to check */
+){
+  u8 *aNode = 0;
+  int nNode = 0;
+
+  assert( iNode==1 || aParent!=0 );
+  assert( pCheck->nDim>0 );
+
+  aNode = rtreeCheckGetNode(pCheck, iNode, &nNode);
+  if( aNode ){
+    if( nNode<4 ){
+      rtreeCheckAppendMsg(pCheck,
+          "Node %lld is too small (%d bytes)", iNode, nNode
+      );
+    }else{
+      int nCell;                  /* Number of cells on page */
+      int i;                      /* Used to iterate through cells */
+      if( aParent==0 ){
+        iDepth = readInt16(aNode);
+        if( iDepth>RTREE_MAX_DEPTH ){
+          rtreeCheckAppendMsg(pCheck, "Rtree depth out of range (%d)", iDepth);
+          sqlite3_free(aNode);
+          return;
+        }
+      }
+      nCell = readInt16(&aNode[2]);
+      if( (4 + nCell*(8 + pCheck->nDim*2*4))>nNode ){
+        rtreeCheckAppendMsg(pCheck,
+            "Node %lld is too small for cell count of %d (%d bytes)",
+            iNode, nCell, nNode
+        );
+      }else{
+        for(i=0; i<nCell; i++){
+          u8 *pCell = &aNode[4 + i*(8 + pCheck->nDim*2*4)];
+          i64 iVal = readInt64(pCell);
+          rtreeCheckCellCoord(pCheck, iNode, i, &pCell[8], aParent);
+
+          if( iDepth>0 ){
+            rtreeCheckMapping(pCheck, 0, iVal, iNode);
+            rtreeCheckNode(pCheck, iDepth-1, &pCell[8], iVal);
+            pCheck->nNonLeaf++;
+          }else{
+            rtreeCheckMapping(pCheck, 1, iVal, iNode);
+            pCheck->nLeaf++;
+          }
+        }
+      }
+    }
+    sqlite3_free(aNode);
+  }
+}
+
+/*
+** The second argument to this function must be either "_rowid" or
+** "_parent". This function checks that the number of entries in the
+** %_rowid or %_parent table is exactly nExpect. If not, it adds
+** an error message to the report in the RtreeCheck object indicated
+** by the first argument.
+*/
+static void rtreeCheckCount(RtreeCheck *pCheck, const char *zTbl, i64 nExpect){
+  if( pCheck->rc==SQLITE_OK ){
+    sqlite3_stmt *pCount;
+    pCount = rtreeCheckPrepare(pCheck, "SELECT count(*) FROM %Q.'%q%s'",
+        pCheck->zDb, pCheck->zTab, zTbl
+    );
+    if( pCount ){
+      if( sqlite3_step(pCount)==SQLITE_ROW ){
+        i64 nActual = sqlite3_column_int64(pCount, 0);
+        if( nActual!=nExpect ){
+          rtreeCheckAppendMsg(pCheck, "Wrong number of entries in %%%s table"
+              " - expected %lld, actual %lld" , zTbl, nExpect, nActual
+          );
+        }
+      }
+      pCheck->rc = sqlite3_finalize(pCount);
+    }
+  }
+}
+
+/*
+** This function does the bulk of the work for the rtree integrity-check.
+** It is called by rtreecheck(), which is the SQL function implementation.
+*/
+static int rtreeCheckTable(
+  sqlite3 *db,                    /* Database handle to access db through */
+  const char *zDb,                /* Name of db ("main", "temp" etc.) */
+  const char *zTab,               /* Name of rtree table to check */
+  char **pzReport                 /* OUT: sqlite3_malloc'd report text */
+){
+  RtreeCheck check;               /* Common context for various routines */
+  sqlite3_stmt *pStmt = 0;        /* Used to find column count of rtree table */
+  int nAux = 0;                   /* Number of extra columns. */
+
+  /* Initialize the context object */
+  memset(&check, 0, sizeof(check));
+  check.db = db;
+  check.zDb = zDb;
+  check.zTab = zTab;
+
+  /* Find the number of auxiliary columns */
+  pStmt = rtreeCheckPrepare(&check, "SELECT * FROM %Q.'%q_rowid'", zDb, zTab);
+  if( pStmt ){
+    nAux = sqlite3_column_count(pStmt) - 2;
+    sqlite3_finalize(pStmt);
+  }else
+  if( check.rc!=SQLITE_NOMEM ){
+    check.rc = SQLITE_OK;
+  }
+
+  /* Find number of dimensions in the rtree table. */
+  pStmt = rtreeCheckPrepare(&check, "SELECT * FROM %Q.%Q", zDb, zTab);
+  if( pStmt ){
+    int rc;
+    check.nDim = (sqlite3_column_count(pStmt) - 1 - nAux) / 2;
+    if( check.nDim<1 ){
+      rtreeCheckAppendMsg(&check, "Schema corrupt or not an rtree");
+    }else if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      check.bInt = (sqlite3_column_type(pStmt, 1)==SQLITE_INTEGER);
+    }
+    rc = sqlite3_finalize(pStmt);
+    if( rc!=SQLITE_CORRUPT ) check.rc = rc;
+  }
+
+  /* Do the actual integrity-check */
+  if( check.nDim>=1 ){
+    if( check.rc==SQLITE_OK ){
+      rtreeCheckNode(&check, 0, 0, 1);
+    }
+    rtreeCheckCount(&check, "_rowid", check.nLeaf);
+    rtreeCheckCount(&check, "_parent", check.nNonLeaf);
+  }
+
+  /* Finalize SQL statements used by the integrity-check */
+  sqlite3_finalize(check.pGetNode);
+  sqlite3_finalize(check.aCheckMapping[0]);
+  sqlite3_finalize(check.aCheckMapping[1]);
+
+  *pzReport = check.zReport;
+  return check.rc;
+}
+
+/*
+** Implementation of the xIntegrity method for Rtree.
+*/
+static int rtreeIntegrity(
+  sqlite3_vtab *pVtab,   /* The virtual table to check */
+  const char *zSchema,   /* Schema in which the virtual table lives */
+  const char *zName,     /* Name of the virtual table */
+  int isQuick,           /* True for a quick_check */
+  char **pzErr           /* Write results here */
+){
+  Rtree *pRtree = (Rtree*)pVtab;
+  int rc;
+  assert( pzErr!=0 && *pzErr==0 );
+  UNUSED_PARAMETER(zSchema);
+  UNUSED_PARAMETER(zName);
+  UNUSED_PARAMETER(isQuick);
+  rc = rtreeCheckTable(pRtree->db, pRtree->zDb, pRtree->zName, pzErr);
+  if( rc==SQLITE_OK && *pzErr ){
+    *pzErr = sqlite3_mprintf("In RTree %s.%s:\n%z",
+                 pRtree->zDb, pRtree->zName, *pzErr);
+    if( (*pzErr)==0 ) rc = SQLITE_NOMEM;
+  }
+  return rc;
+}
+
+/*
+** Usage:
+**
+**   rtreecheck(<rtree-table>);
+**   rtreecheck(<database>, <rtree-table>);
+**
+** Invoking this SQL function runs an integrity-check on the named rtree
+** table. The integrity-check verifies the following:
+**
+**   1. For each cell in the r-tree structure (%_node table), that:
+**
+**       a) for each dimension, (coord1 <= coord2).
+**
+**       b) unless the cell is on the root node, that the cell is bounded
+**          by the parent cell on the parent node.
+**
+**       c) for leaf nodes, that there is an entry in the %_rowid
+**          table corresponding to the cell's rowid value that
+**          points to the correct node.
+**
+**       d) for cells on non-leaf nodes, that there is an entry in the
+**          %_parent table mapping from the cell's child node to the
+**          node that it resides on.
+**
+**   2. That there are the same number of entries in the %_rowid table
+**      as there are leaf cells in the r-tree structure, and that there
+**      is a leaf cell that corresponds to each entry in the %_rowid table.
+**
+**   3. That there are the same number of entries in the %_parent table
+**      as there are non-leaf cells in the r-tree structure, and that
+**      there is a non-leaf cell that corresponds to each entry in the
+**      %_parent table.
+*/
+static void rtreecheck(
+  sqlite3_context *ctx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  if( nArg!=1 && nArg!=2 ){
+    sqlite3_result_error(ctx,
+        "wrong number of arguments to function rtreecheck()", -1
+    );
+  }else{
+    int rc;
+    char *zReport = 0;
+    const char *zDb = (const char*)sqlite3_value_text(apArg[0]);
+    const char *zTab;
+    if( nArg==1 ){
+      zTab = zDb;
+      zDb = "main";
+    }else{
+      zTab = (const char*)sqlite3_value_text(apArg[1]);
+    }
+    rc = rtreeCheckTable(sqlite3_context_db_handle(ctx), zDb, zTab, &zReport);
+    if( rc==SQLITE_OK ){
+      sqlite3_result_text(ctx, zReport ? zReport : "ok", -1, SQLITE_TRANSIENT);
+    }else{
+      sqlite3_result_error_code(ctx, rc);
+    }
+    sqlite3_free(zReport);
+  }
+}
+
+/* Conditionally include the geopoly code */
+#ifdef SQLITE_ENABLE_GEOPOLY
+/************** Include geopoly.c in the middle of rtree.c *******************/
+/************** Begin file geopoly.c *****************************************/
+/*
+** 2018-05-25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file implements an alternative R-Tree virtual table that
+** uses polygons to express the boundaries of 2-dimensional objects.
+**
+** This file is #include-ed onto the end of "rtree.c" so that it has
+** access to all of the R-Tree internals.
+*/
+/* #include <stdlib.h> */
+
+/* Enable -DGEOPOLY_ENABLE_DEBUG for debugging facilities */
+#ifdef GEOPOLY_ENABLE_DEBUG
+  static int geo_debug = 0;
+# define GEODEBUG(X) if(geo_debug)printf X
+#else
+# define GEODEBUG(X)
+#endif
+
+/* Character class routines */
+#ifdef sqlite3Isdigit
+   /* Use the SQLite core versions if this routine is part of the
+   ** SQLite amalgamation */
+#  define safe_isdigit(x)  sqlite3Isdigit(x)
+#  define safe_isalnum(x)  sqlite3Isalnum(x)
+#  define safe_isxdigit(x) sqlite3Isxdigit(x)
+#else
+   /* Use the standard library for separate compilation */
+#include <ctype.h>  /* amalgamator: keep */
+#  define safe_isdigit(x)  isdigit((unsigned char)(x))
+#  define safe_isalnum(x)  isalnum((unsigned char)(x))
+#  define safe_isxdigit(x) isxdigit((unsigned char)(x))
+#endif
+
+#ifndef JSON_NULL   /* The following stuff repeats things found in json1 */
+/*
+** Growing our own isspace() routine this way is twice as fast as
+** the library isspace() function.
+*/
+static const char geopolyIsSpace[] = {
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 1, 1, 0, 0, 1, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  1, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+};
+#define fast_isspace(x) (geopolyIsSpace[(unsigned char)x])
+#endif /* JSON NULL - back to original code */
+
+/* Compiler and version */
+#ifndef GCC_VERSION
+#if defined(__GNUC__) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define GCC_VERSION (__GNUC__*1000000+__GNUC_MINOR__*1000+__GNUC_PATCHLEVEL__)
+#else
+# define GCC_VERSION 0
+#endif
+#endif
+#ifndef MSVC_VERSION
+#if defined(_MSC_VER) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define MSVC_VERSION _MSC_VER
+#else
+# define MSVC_VERSION 0
+#endif
+#endif
+
+/* Datatype for coordinates
+*/
+typedef float GeoCoord;
+
+/*
+** Internal representation of a polygon.
+**
+** The polygon consists of a sequence of vertexes.  There is a line
+** segment between each pair of vertexes, and one final segment from
+** the last vertex back to the first.  (This differs from the GeoJSON
+** standard in which the final vertex is a repeat of the first.)
+**
+** The polygon follows the right-hand rule.  The area to the right of
+** each segment is "outside" and the area to the left is "inside".
+**
+** The on-disk representation consists of a 4-byte header followed by
+** the values.  The 4-byte header is:
+**
+**      encoding    (1 byte)   0=big-endian, 1=little-endian
+**      nvertex     (3 bytes)  Number of vertexes as a big-endian integer
+**
+** Enough space is allocated for 4 coordinates, to work around over-zealous
+** warnings coming from some compiler (notably, clang). In reality, the size
+** of each GeoPoly memory allocate is adjusted as necessary so that the
+** GeoPoly.a[] array at the end is the appropriate size.
+*/
+typedef struct GeoPoly GeoPoly;
+struct GeoPoly {
+  int nVertex;          /* Number of vertexes */
+  unsigned char hdr[4]; /* Header for on-disk representation */
+  GeoCoord a[8];        /* 2*nVertex values. X (longitude) first, then Y */
+};
+
+/* The size of a memory allocation needed for a GeoPoly object sufficient
+** to hold N coordinate pairs.
+*/
+#define GEOPOLY_SZ(N)  (sizeof(GeoPoly) + sizeof(GeoCoord)*2*((N)-4))
+
+/* Macros to access coordinates of a GeoPoly.
+** We have to use these macros, rather than just say p->a[i] in order
+** to silence (incorrect) UBSAN warnings if the array index is too large.
+*/
+#define GeoX(P,I)  (((GeoCoord*)(P)->a)[(I)*2])
+#define GeoY(P,I)  (((GeoCoord*)(P)->a)[(I)*2+1])
+
+
+/*
+** State of a parse of a GeoJSON input.
+*/
+typedef struct GeoParse GeoParse;
+struct GeoParse {
+  const unsigned char *z;   /* Unparsed input */
+  int nVertex;              /* Number of vertexes in a[] */
+  int nAlloc;               /* Space allocated to a[] */
+  int nErr;                 /* Number of errors encountered */
+  GeoCoord *a;          /* Array of vertexes.  From sqlite3_malloc64() */
+};
+
+/* Do a 4-byte byte swap */
+static void geopolySwab32(unsigned char *a){
+  unsigned char t = a[0];
+  a[0] = a[3];
+  a[3] = t;
+  t = a[1];
+  a[1] = a[2];
+  a[2] = t;
+}
+
+/* Skip whitespace.  Return the next non-whitespace character. */
+static char geopolySkipSpace(GeoParse *p){
+  while( fast_isspace(p->z[0]) ) p->z++;
+  return p->z[0];
+}
+
+/* Parse out a number.  Write the value into *pVal if pVal!=0.
+** return non-zero on success and zero if the next token is not a number.
+*/
+static int geopolyParseNumber(GeoParse *p, GeoCoord *pVal){
+  char c = geopolySkipSpace(p);
+  const unsigned char *z = p->z;
+  int j = 0;
+  int seenDP = 0;
+  int seenE = 0;
+  if( c=='-' ){
+    j = 1;
+    c = z[j];
+  }
+  if( c=='0' && z[j+1]>='0' && z[j+1]<='9' ) return 0;
+  for(;; j++){
+    c = z[j];
+    if( safe_isdigit(c) ) continue;
+    if( c=='.' ){
+      if( z[j-1]=='-' ) return 0;
+      if( seenDP ) return 0;
+      seenDP = 1;
+      continue;
+    }
+    if( c=='e' || c=='E' ){
+      if( z[j-1]<'0' ) return 0;
+      if( seenE ) return -1;
+      seenDP = seenE = 1;
+      c = z[j+1];
+      if( c=='+' || c=='-' ){
+        j++;
+        c = z[j+1];
+      }
+      if( c<'0' || c>'9' ) return 0;
+      continue;
+    }
+    break;
+  }
+  if( z[j-1]<'0' ) return 0;
+  if( pVal ){
+#ifdef SQLITE_AMALGAMATION
+     /* The sqlite3AtoF() routine is much much faster than atof(), if it
+     ** is available */
+     double r;
+     (void)sqlite3AtoF((const char*)p->z, &r, j, SQLITE_UTF8);
+     *pVal = r;
+#else
+     *pVal = (GeoCoord)atof((const char*)p->z);
+#endif
+  }
+  p->z += j;
+  return 1;
+}
+
+/*
+** If the input is a well-formed JSON array of coordinates with at least
+** four coordinates and where each coordinate is itself a two-value array,
+** then convert the JSON into a GeoPoly object and return a pointer to
+** that object.
+**
+** If any error occurs, return NULL.
+*/
+static GeoPoly *geopolyParseJson(const unsigned char *z, int *pRc){
+  GeoParse s;
+  int rc = SQLITE_OK;
+  memset(&s, 0, sizeof(s));
+  s.z = z;
+  if( geopolySkipSpace(&s)=='[' ){
+    s.z++;
+    while( geopolySkipSpace(&s)=='[' ){
+      int ii = 0;
+      char c;
+      s.z++;
+      if( s.nVertex>=s.nAlloc ){
+        GeoCoord *aNew;
+        s.nAlloc = s.nAlloc*2 + 16;
+        aNew = sqlite3_realloc64(s.a, s.nAlloc*sizeof(GeoCoord)*2 );
+        if( aNew==0 ){
+          rc = SQLITE_NOMEM;
+          s.nErr++;
+          break;
+        }
+        s.a = aNew;
+      }
+      while( geopolyParseNumber(&s, ii<=1 ? &s.a[s.nVertex*2+ii] : 0) ){
+        ii++;
+        if( ii==2 ) s.nVertex++;
+        c = geopolySkipSpace(&s);
+        s.z++;
+        if( c==',' ) continue;
+        if( c==']' && ii>=2 ) break;
+        s.nErr++;
+        rc = SQLITE_ERROR;
+        goto parse_json_err;
+      }
+      if( geopolySkipSpace(&s)==',' ){
+        s.z++;
+        continue;
+      }
+      break;
+    }
+    if( geopolySkipSpace(&s)==']'
+     && s.nVertex>=4
+     && s.a[0]==s.a[s.nVertex*2-2]
+     && s.a[1]==s.a[s.nVertex*2-1]
+     && (s.z++, geopolySkipSpace(&s)==0)
+    ){
+      GeoPoly *pOut;
+      int x = 1;
+      s.nVertex--;  /* Remove the redundant vertex at the end */
+      pOut = sqlite3_malloc64( GEOPOLY_SZ((sqlite3_int64)s.nVertex) );
+      x = 1;
+      if( pOut==0 ) goto parse_json_err;
+      pOut->nVertex = s.nVertex;
+      memcpy(pOut->a, s.a, s.nVertex*2*sizeof(GeoCoord));
+      pOut->hdr[0] = *(unsigned char*)&x;
+      pOut->hdr[1] = (s.nVertex>>16)&0xff;
+      pOut->hdr[2] = (s.nVertex>>8)&0xff;
+      pOut->hdr[3] = s.nVertex&0xff;
+      sqlite3_free(s.a);
+      if( pRc ) *pRc = SQLITE_OK;
+      return pOut;
+    }else{
+      s.nErr++;
+      rc = SQLITE_ERROR;
+    }
+  }
+parse_json_err:
+  if( pRc ) *pRc = rc;
+  sqlite3_free(s.a);
+  return 0;
+}
+
+/*
+** Given a function parameter, try to interpret it as a polygon, either
+** in the binary format or JSON text.  Compute a GeoPoly object and
+** return a pointer to that object.  Or if the input is not a well-formed
+** polygon, put an error message in sqlite3_context and return NULL.
+*/
+static GeoPoly *geopolyFuncParam(
+  sqlite3_context *pCtx,      /* Context for error messages */
+  sqlite3_value *pVal,        /* The value to decode */
+  int *pRc                    /* Write error here */
+){
+  GeoPoly *p = 0;
+  int nByte;
+  testcase( pCtx==0 );
+  if( sqlite3_value_type(pVal)==SQLITE_BLOB
+   && (nByte = sqlite3_value_bytes(pVal))>=(int)(4+6*sizeof(GeoCoord))
+  ){
+    const unsigned char *a = sqlite3_value_blob(pVal);
+    int nVertex;
+    if( a==0 ){
+      if( pCtx ) sqlite3_result_error_nomem(pCtx);
+      return 0;
+    }
+    nVertex = (a[1]<<16) + (a[2]<<8) + a[3];
+    if( (a[0]==0 || a[0]==1)
+     && (nVertex*2*sizeof(GeoCoord) + 4)==(unsigned int)nByte
+    ){
+      p = sqlite3_malloc64( sizeof(*p) + (nVertex-1)*2*sizeof(GeoCoord) );
+      if( p==0 ){
+        if( pRc ) *pRc = SQLITE_NOMEM;
+        if( pCtx ) sqlite3_result_error_nomem(pCtx);
+      }else{
+        int x = 1;
+        p->nVertex = nVertex;
+        memcpy(p->hdr, a, nByte);
+        if( a[0] != *(unsigned char*)&x ){
+          int ii;
+          for(ii=0; ii<nVertex; ii++){
+            geopolySwab32((unsigned char*)&GeoX(p,ii));
+            geopolySwab32((unsigned char*)&GeoY(p,ii));
+          }
+          p->hdr[0] ^= 1;
+        }
+      }
+    }
+    if( pRc ) *pRc = SQLITE_OK;
+    return p;
+  }else if( sqlite3_value_type(pVal)==SQLITE_TEXT ){
+    const unsigned char *zJson = sqlite3_value_text(pVal);
+    if( zJson==0 ){
+      if( pRc ) *pRc = SQLITE_NOMEM;
+      return 0;
+    }
+    return geopolyParseJson(zJson, pRc);
+  }else{
+    if( pRc ) *pRc = SQLITE_ERROR;
+    return 0;
+  }
+}
+
+/*
+** Implementation of the geopoly_blob(X) function.
+**
+** If the input is a well-formed Geopoly BLOB or JSON string
+** then return the BLOB representation of the polygon.  Otherwise
+** return NULL.
+*/
+static void geopolyBlobFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  (void)argc;
+  if( p ){
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** SQL function:     geopoly_json(X)
+**
+** Interpret X as a polygon and render it as a JSON array
+** of coordinates.  Or, if X is not a valid polygon, return NULL.
+*/
+static void geopolyJsonFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  (void)argc;
+  if( p ){
+    sqlite3 *db = sqlite3_context_db_handle(context);
+    sqlite3_str *x = sqlite3_str_new(db);
+    int i;
+    sqlite3_str_append(x, "[", 1);
+    for(i=0; i<p->nVertex; i++){
+      sqlite3_str_appendf(x, "[%!g,%!g],", GeoX(p,i), GeoY(p,i));
+    }
+    sqlite3_str_appendf(x, "[%!g,%!g]]", GeoX(p,0), GeoY(p,0));
+    sqlite3_result_text(context, sqlite3_str_finish(x), -1, sqlite3_free);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** SQL function:     geopoly_svg(X, ....)
+**
+** Interpret X as a polygon and render it as a SVG <polyline>.
+** Additional arguments are added as attributes to the <polyline>.
+*/
+static void geopolySvgFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p;
+  if( argc<1 ) return;
+  p = geopolyFuncParam(context, argv[0], 0);
+  if( p ){
+    sqlite3 *db = sqlite3_context_db_handle(context);
+    sqlite3_str *x = sqlite3_str_new(db);
+    int i;
+    char cSep = '\'';
+    sqlite3_str_appendf(x, "<polyline points=");
+    for(i=0; i<p->nVertex; i++){
+      sqlite3_str_appendf(x, "%c%g,%g", cSep, GeoX(p,i), GeoY(p,i));
+      cSep = ' ';
+    }
+    sqlite3_str_appendf(x, " %g,%g'", GeoX(p,0), GeoY(p,0));
+    for(i=1; i<argc; i++){
+      const char *z = (const char*)sqlite3_value_text(argv[i]);
+      if( z && z[0] ){
+        sqlite3_str_appendf(x, " %s", z);
+      }
+    }
+    sqlite3_str_appendf(x, "></polyline>");
+    sqlite3_result_text(context, sqlite3_str_finish(x), -1, sqlite3_free);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** SQL Function:      geopoly_xform(poly, A, B, C, D, E, F)
+**
+** Transform and/or translate a polygon as follows:
+**
+**      x1 = A*x0 + B*y0 + E
+**      y1 = C*x0 + D*y0 + F
+**
+** For a translation:
+**
+**      geopoly_xform(poly, 1, 0, 0, 1, x-offset, y-offset)
+**
+** Rotate by R around the point (0,0):
+**
+**      geopoly_xform(poly, cos(R), sin(R), -sin(R), cos(R), 0, 0)
+*/
+static void geopolyXformFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  double A = sqlite3_value_double(argv[1]);
+  double B = sqlite3_value_double(argv[2]);
+  double C = sqlite3_value_double(argv[3]);
+  double D = sqlite3_value_double(argv[4]);
+  double E = sqlite3_value_double(argv[5]);
+  double F = sqlite3_value_double(argv[6]);
+  GeoCoord x1, y1, x0, y0;
+  int ii;
+  (void)argc;
+  if( p ){
+    for(ii=0; ii<p->nVertex; ii++){
+      x0 = GeoX(p,ii);
+      y0 = GeoY(p,ii);
+      x1 = (GeoCoord)(A*x0 + B*y0 + E);
+      y1 = (GeoCoord)(C*x0 + D*y0 + F);
+      GeoX(p,ii) = x1;
+      GeoY(p,ii) = y1;
+    }
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Compute the area enclosed by the polygon.
+**
+** This routine can also be used to detect polygons that rotate in
+** the wrong direction.  Polygons are suppose to be counter-clockwise (CCW).
+** This routine returns a negative value for clockwise (CW) polygons.
+*/
+static double geopolyArea(GeoPoly *p){
+  double rArea = 0.0;
+  int ii;
+  for(ii=0; ii<p->nVertex-1; ii++){
+    rArea += (GeoX(p,ii) - GeoX(p,ii+1))           /* (x0 - x1) */
+              * (GeoY(p,ii) + GeoY(p,ii+1))        /* (y0 + y1) */
+              * 0.5;
+  }
+  rArea += (GeoX(p,ii) - GeoX(p,0))                /* (xN - x0) */
+           * (GeoY(p,ii) + GeoY(p,0))              /* (yN + y0) */
+           * 0.5;
+  return rArea;
+}
+
+/*
+** Implementation of the geopoly_area(X) function.
+**
+** If the input is a well-formed Geopoly BLOB then return the area
+** enclosed by the polygon.  If the polygon circulates clockwise instead
+** of counterclockwise (as it should) then return the negative of the
+** enclosed area.  Otherwise return NULL.
+*/
+static void geopolyAreaFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  (void)argc;
+  if( p ){
+    sqlite3_result_double(context, geopolyArea(p));
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Implementation of the geopoly_ccw(X) function.
+**
+** If the rotation of polygon X is clockwise (incorrect) instead of
+** counter-clockwise (the correct winding order according to RFC7946)
+** then reverse the order of the vertexes in polygon X.
+**
+** In other words, this routine returns a CCW polygon regardless of the
+** winding order of its input.
+**
+** Use this routine to sanitize historical inputs that that sometimes
+** contain polygons that wind in the wrong direction.
+*/
+static void geopolyCcwFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  (void)argc;
+  if( p ){
+    if( geopolyArea(p)<0.0 ){
+      int ii, jj;
+      for(ii=1, jj=p->nVertex-1; ii<jj; ii++, jj--){
+        GeoCoord t = GeoX(p,ii);
+        GeoX(p,ii) = GeoX(p,jj);
+        GeoX(p,jj) = t;
+        t = GeoY(p,ii);
+        GeoY(p,ii) = GeoY(p,jj);
+        GeoY(p,jj) = t;
+      }
+    }
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+#define GEOPOLY_PI 3.1415926535897932385
+
+/* Fast approximation for sine(X) for X between -0.5*pi and 2*pi
+*/
+static double geopolySine(double r){
+  assert( r>=-0.5*GEOPOLY_PI && r<=2.0*GEOPOLY_PI );
+  if( r>=1.5*GEOPOLY_PI ){
+    r -= 2.0*GEOPOLY_PI;
+  }
+  if( r>=0.5*GEOPOLY_PI ){
+    return -geopolySine(r-GEOPOLY_PI);
+  }else{
+    double r2 = r*r;
+    double r3 = r2*r;
+    double r5 = r3*r2;
+    return 0.9996949*r - 0.1656700*r3 + 0.0075134*r5;
+  }
+}
+
+/*
+** Function:   geopoly_regular(X,Y,R,N)
+**
+** Construct a simple, convex, regular polygon centered at X, Y
+** with circumradius R and with N sides.
+*/
+static void geopolyRegularFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  double x = sqlite3_value_double(argv[0]);
+  double y = sqlite3_value_double(argv[1]);
+  double r = sqlite3_value_double(argv[2]);
+  int n = sqlite3_value_int(argv[3]);
+  int i;
+  GeoPoly *p;
+  (void)argc;
+
+  if( n<3 || r<=0.0 ) return;
+  if( n>1000 ) n = 1000;
+  p = sqlite3_malloc64( sizeof(*p) + (n-1)*2*sizeof(GeoCoord) );
+  if( p==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+  i = 1;
+  p->hdr[0] = *(unsigned char*)&i;
+  p->hdr[1] = 0;
+  p->hdr[2] = (n>>8)&0xff;
+  p->hdr[3] = n&0xff;
+  for(i=0; i<n; i++){
+    double rAngle = 2.0*GEOPOLY_PI*i/n;
+    GeoX(p,i) = x - r*geopolySine(rAngle-0.5*GEOPOLY_PI);
+    GeoY(p,i) = y + r*geopolySine(rAngle);
+  }
+  sqlite3_result_blob(context, p->hdr, 4+8*n, SQLITE_TRANSIENT);
+  sqlite3_free(p);
+}
+
+/*
+** If pPoly is a polygon, compute its bounding box. Then:
+**
+**    (1) if aCoord!=0 store the bounding box in aCoord, returning NULL
+**    (2) otherwise, compute a GeoPoly for the bounding box and return the
+**        new GeoPoly
+**
+** If pPoly is NULL but aCoord is not NULL, then compute a new GeoPoly from
+** the bounding box in aCoord and return a pointer to that GeoPoly.
+*/
+static GeoPoly *geopolyBBox(
+  sqlite3_context *context,   /* For recording the error */
+  sqlite3_value *pPoly,       /* The polygon */
+  RtreeCoord *aCoord,         /* Results here */
+  int *pRc                    /* Error code here */
+){
+  GeoPoly *pOut = 0;
+  GeoPoly *p;
+  float mnX, mxX, mnY, mxY;
+  if( pPoly==0 && aCoord!=0 ){
+    p = 0;
+    mnX = aCoord[0].f;
+    mxX = aCoord[1].f;
+    mnY = aCoord[2].f;
+    mxY = aCoord[3].f;
+    goto geopolyBboxFill;
+  }else{
+    p = geopolyFuncParam(context, pPoly, pRc);
+  }
+  if( p ){
+    int ii;
+    mnX = mxX = GeoX(p,0);
+    mnY = mxY = GeoY(p,0);
+    for(ii=1; ii<p->nVertex; ii++){
+      double r = GeoX(p,ii);
+      if( r<mnX ) mnX = (float)r;
+      else if( r>mxX ) mxX = (float)r;
+      r = GeoY(p,ii);
+      if( r<mnY ) mnY = (float)r;
+      else if( r>mxY ) mxY = (float)r;
+    }
+    if( pRc ) *pRc = SQLITE_OK;
+    if( aCoord==0 ){
+      geopolyBboxFill:
+      pOut = sqlite3_realloc64(p, GEOPOLY_SZ(4));
+      if( pOut==0 ){
+        sqlite3_free(p);
+        if( context ) sqlite3_result_error_nomem(context);
+        if( pRc ) *pRc = SQLITE_NOMEM;
+        return 0;
+      }
+      pOut->nVertex = 4;
+      ii = 1;
+      pOut->hdr[0] = *(unsigned char*)ⅈ
+      pOut->hdr[1] = 0;
+      pOut->hdr[2] = 0;
+      pOut->hdr[3] = 4;
+      GeoX(pOut,0) = mnX;
+      GeoY(pOut,0) = mnY;
+      GeoX(pOut,1) = mxX;
+      GeoY(pOut,1) = mnY;
+      GeoX(pOut,2) = mxX;
+      GeoY(pOut,2) = mxY;
+      GeoX(pOut,3) = mnX;
+      GeoY(pOut,3) = mxY;
+    }else{
+      sqlite3_free(p);
+      aCoord[0].f = mnX;
+      aCoord[1].f = mxX;
+      aCoord[2].f = mnY;
+      aCoord[3].f = mxY;
+    }
+  }else if( aCoord ){
+    memset(aCoord, 0, sizeof(RtreeCoord)*4);
+  }
+  return pOut;
+}
+
+/*
+** Implementation of the geopoly_bbox(X) SQL function.
+*/
+static void geopolyBBoxFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyBBox(context, argv[0], 0, 0);
+  (void)argc;
+  if( p ){
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** State vector for the geopoly_group_bbox() aggregate function.
+*/
+typedef struct GeoBBox GeoBBox;
+struct GeoBBox {
+  int isInit;
+  RtreeCoord a[4];
+};
+
+
+/*
+** Implementation of the geopoly_group_bbox(X) aggregate SQL function.
+*/
+static void geopolyBBoxStep(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  RtreeCoord a[4];
+  int rc = SQLITE_OK;
+  (void)argc;
+  (void)geopolyBBox(context, argv[0], a, &rc);
+  if( rc==SQLITE_OK ){
+    GeoBBox *pBBox;
+    pBBox = (GeoBBox*)sqlite3_aggregate_context(context, sizeof(*pBBox));
+    if( pBBox==0 ) return;
+    if( pBBox->isInit==0 ){
+      pBBox->isInit = 1;
+      memcpy(pBBox->a, a, sizeof(RtreeCoord)*4);
+    }else{
+      if( a[0].f < pBBox->a[0].f ) pBBox->a[0] = a[0];
+      if( a[1].f > pBBox->a[1].f ) pBBox->a[1] = a[1];
+      if( a[2].f < pBBox->a[2].f ) pBBox->a[2] = a[2];
+      if( a[3].f > pBBox->a[3].f ) pBBox->a[3] = a[3];
+    }
+  }
+}
+static void geopolyBBoxFinal(
+  sqlite3_context *context
+){
+  GeoPoly *p;
+  GeoBBox *pBBox;
+  pBBox = (GeoBBox*)sqlite3_aggregate_context(context, 0);
+  if( pBBox==0 ) return;
+  p = geopolyBBox(context, 0, pBBox->a, 0);
+  if( p ){
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+
+/*
+** Determine if point (x0,y0) is beneath line segment (x1,y1)->(x2,y2).
+** Returns:
+**
+**    +2  x0,y0 is on the line segement
+**
+**    +1  x0,y0 is beneath line segment
+**
+**    0   x0,y0 is not on or beneath the line segment or the line segment
+**        is vertical and x0,y0 is not on the line segment
+**
+** The left-most coordinate min(x1,x2) is not considered to be part of
+** the line segment for the purposes of this analysis.
+*/
+static int pointBeneathLine(
+  double x0, double y0,
+  double x1, double y1,
+  double x2, double y2
+){
+  double y;
+  if( x0==x1 && y0==y1 ) return 2;
+  if( x1<x2 ){
+    if( x0<=x1 || x0>x2 ) return 0;
+  }else if( x1>x2 ){
+    if( x0<=x2 || x0>x1 ) return 0;
+  }else{
+    /* Vertical line segment */
+    if( x0!=x1 ) return 0;
+    if( y0<y1 && y0<y2 ) return 0;
+    if( y0>y1 && y0>y2 ) return 0;
+    return 2;
+  }
+  y = y1 + (y2-y1)*(x0-x1)/(x2-x1);
+  if( y0==y ) return 2;
+  if( y0<y ) return 1;
+  return 0;
+}
+
+/*
+** SQL function:    geopoly_contains_point(P,X,Y)
+**
+** Return +2 if point X,Y is within polygon P.
+** Return +1 if point X,Y is on the polygon boundary.
+** Return 0 if point X,Y is outside the polygon
+*/
+static void geopolyContainsPointFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p1 = geopolyFuncParam(context, argv[0], 0);
+  double x0 = sqlite3_value_double(argv[1]);
+  double y0 = sqlite3_value_double(argv[2]);
+  int v = 0;
+  int cnt = 0;
+  int ii;
+  (void)argc;
+
+  if( p1==0 ) return;
+  for(ii=0; ii<p1->nVertex-1; ii++){
+    v = pointBeneathLine(x0,y0,GeoX(p1,ii), GeoY(p1,ii),
+                               GeoX(p1,ii+1),GeoY(p1,ii+1));
+    if( v==2 ) break;
+    cnt += v;
+  }
+  if( v!=2 ){
+    v = pointBeneathLine(x0,y0,GeoX(p1,ii), GeoY(p1,ii),
+                               GeoX(p1,0),  GeoY(p1,0));
+  }
+  if( v==2 ){
+    sqlite3_result_int(context, 1);
+  }else if( ((v+cnt)&1)==0 ){
+    sqlite3_result_int(context, 0);
+  }else{
+    sqlite3_result_int(context, 2);
+  }
+  sqlite3_free(p1);
+}
+
+/* Forward declaration */
+static int geopolyOverlap(GeoPoly *p1, GeoPoly *p2);
+
+/*
+** SQL function:    geopoly_within(P1,P2)
+**
+** Return +2 if P1 and P2 are the same polygon
+** Return +1 if P2 is contained within P1
+** Return 0 if any part of P2 is on the outside of P1
+**
+*/
+static void geopolyWithinFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p1 = geopolyFuncParam(context, argv[0], 0);
+  GeoPoly *p2 = geopolyFuncParam(context, argv[1], 0);
+  (void)argc;
+  if( p1 && p2 ){
+    int x = geopolyOverlap(p1, p2);
+    if( x<0 ){
+      sqlite3_result_error_nomem(context);
+    }else{
+      sqlite3_result_int(context, x==2 ? 1 : x==4 ? 2 : 0);
+    }
+  }
+  sqlite3_free(p1);
+  sqlite3_free(p2);
+}
+
+/* Objects used by the overlap algorihm. */
+typedef struct GeoEvent GeoEvent;
+typedef struct GeoSegment GeoSegment;
+typedef struct GeoOverlap GeoOverlap;
+struct GeoEvent {
+  double x;              /* X coordinate at which event occurs */
+  int eType;             /* 0 for ADD, 1 for REMOVE */
+  GeoSegment *pSeg;      /* The segment to be added or removed */
+  GeoEvent *pNext;       /* Next event in the sorted list */
+};
+struct GeoSegment {
+  double C, B;           /* y = C*x + B */
+  double y;              /* Current y value */
+  float y0;              /* Initial y value */
+  unsigned char side;    /* 1 for p1, 2 for p2 */
+  unsigned int idx;      /* Which segment within the side */
+  GeoSegment *pNext;     /* Next segment in a list sorted by y */
+};
+struct GeoOverlap {
+  GeoEvent *aEvent;          /* Array of all events */
+  GeoSegment *aSegment;      /* Array of all segments */
+  int nEvent;                /* Number of events */
+  int nSegment;              /* Number of segments */
+};
+
+/*
+** Add a single segment and its associated events.
+*/
+static void geopolyAddOneSegment(
+  GeoOverlap *p,
+  GeoCoord x0,
+  GeoCoord y0,
+  GeoCoord x1,
+  GeoCoord y1,
+  unsigned char side,
+  unsigned int idx
+){
+  GeoSegment *pSeg;
+  GeoEvent *pEvent;
+  if( x0==x1 ) return;  /* Ignore vertical segments */
+  if( x0>x1 ){
+    GeoCoord t = x0;
+    x0 = x1;
+    x1 = t;
+    t = y0;
+    y0 = y1;
+    y1 = t;
+  }
+  pSeg = p->aSegment + p->nSegment;
+  p->nSegment++;
+  pSeg->C = (y1-y0)/(x1-x0);
+  pSeg->B = y1 - x1*pSeg->C;
+  pSeg->y0 = y0;
+  pSeg->side = side;
+  pSeg->idx = idx;
+  pEvent = p->aEvent + p->nEvent;
+  p->nEvent++;
+  pEvent->x = x0;
+  pEvent->eType = 0;
+  pEvent->pSeg = pSeg;
+  pEvent = p->aEvent + p->nEvent;
+  p->nEvent++;
+  pEvent->x = x1;
+  pEvent->eType = 1;
+  pEvent->pSeg = pSeg;
+}
+
+
+
+/*
+** Insert all segments and events for polygon pPoly.
+*/
+static void geopolyAddSegments(
+  GeoOverlap *p,          /* Add segments to this Overlap object */
+  GeoPoly *pPoly,         /* Take all segments from this polygon */
+  unsigned char side      /* The side of pPoly */
+){
+  unsigned int i;
+  GeoCoord *x;
+  for(i=0; i<(unsigned)pPoly->nVertex-1; i++){
+    x = &GeoX(pPoly,i);
+    geopolyAddOneSegment(p, x[0], x[1], x[2], x[3], side, i);
+  }
+  x = &GeoX(pPoly,i);
+  geopolyAddOneSegment(p, x[0], x[1], pPoly->a[0], pPoly->a[1], side, i);
+}
+
+/*
+** Merge two lists of sorted events by X coordinate
+*/
+static GeoEvent *geopolyEventMerge(GeoEvent *pLeft, GeoEvent *pRight){
+  GeoEvent head, *pLast;
+  head.pNext = 0;
+  pLast = &head;
+  while( pRight && pLeft ){
+    if( pRight->x <= pLeft->x ){
+      pLast->pNext = pRight;
+      pLast = pRight;
+      pRight = pRight->pNext;
+    }else{
+      pLast->pNext = pLeft;
+      pLast = pLeft;
+      pLeft = pLeft->pNext;
+    }
+  }
+  pLast->pNext = pRight ? pRight : pLeft;
+  return head.pNext;
+}
+
+/*
+** Sort an array of nEvent event objects into a list.
+*/
+static GeoEvent *geopolySortEventsByX(GeoEvent *aEvent, int nEvent){
+  int mx = 0;
+  int i, j;
+  GeoEvent *p;
+  GeoEvent *a[50];
+  for(i=0; i<nEvent; i++){
+    p = &aEvent[i];
+    p->pNext = 0;
+    for(j=0; j<mx && a[j]; j++){
+      p = geopolyEventMerge(a[j], p);
+      a[j] = 0;
+    }
+    a[j] = p;
+    if( j>=mx ) mx = j+1;
+  }
+  p = 0;
+  for(i=0; i<mx; i++){
+    p = geopolyEventMerge(a[i], p);
+  }
+  return p;
+}
+
+/*
+** Merge two lists of sorted segments by Y, and then by C.
+*/
+static GeoSegment *geopolySegmentMerge(GeoSegment *pLeft, GeoSegment *pRight){
+  GeoSegment head, *pLast;
+  head.pNext = 0;
+  pLast = &head;
+  while( pRight && pLeft ){
+    double r = pRight->y - pLeft->y;
+    if( r==0.0 ) r = pRight->C - pLeft->C;
+    if( r<0.0 ){
+      pLast->pNext = pRight;
+      pLast = pRight;
+      pRight = pRight->pNext;
+    }else{
+      pLast->pNext = pLeft;
+      pLast = pLeft;
+      pLeft = pLeft->pNext;
+    }
+  }
+  pLast->pNext = pRight ? pRight : pLeft;
+  return head.pNext;
+}
+
+/*
+** Sort a list of GeoSegments in order of increasing Y and in the event of
+** a tie, increasing C (slope).
+*/
+static GeoSegment *geopolySortSegmentsByYAndC(GeoSegment *pList){
+  int mx = 0;
+  int i;
+  GeoSegment *p;
+  GeoSegment *a[50];
+  while( pList ){
+    p = pList;
+    pList = pList->pNext;
+    p->pNext = 0;
+    for(i=0; i<mx && a[i]; i++){
+      p = geopolySegmentMerge(a[i], p);
+      a[i] = 0;
+    }
+    a[i] = p;
+    if( i>=mx ) mx = i+1;
+  }
+  p = 0;
+  for(i=0; i<mx; i++){
+    p = geopolySegmentMerge(a[i], p);
+  }
+  return p;
+}
+
+/*
+** Determine the overlap between two polygons
+*/
+static int geopolyOverlap(GeoPoly *p1, GeoPoly *p2){
+  sqlite3_int64 nVertex = p1->nVertex + p2->nVertex + 2;
+  GeoOverlap *p;
+  sqlite3_int64 nByte;
+  GeoEvent *pThisEvent;
+  double rX;
+  int rc = 0;
+  int needSort = 0;
+  GeoSegment *pActive = 0;
+  GeoSegment *pSeg;
+  unsigned char aOverlap[4];
+
+  nByte = sizeof(GeoEvent)*nVertex*2
+           + sizeof(GeoSegment)*nVertex
+           + sizeof(GeoOverlap);
+  p = sqlite3_malloc64( nByte );
+  if( p==0 ) return -1;
+  p->aEvent = (GeoEvent*)&p[1];
+  p->aSegment = (GeoSegment*)&p->aEvent[nVertex*2];
+  p->nEvent = p->nSegment = 0;
+  geopolyAddSegments(p, p1, 1);
+  geopolyAddSegments(p, p2, 2);
+  pThisEvent = geopolySortEventsByX(p->aEvent, p->nEvent);
+  rX = pThisEvent && pThisEvent->x==0.0 ? -1.0 : 0.0;
+  memset(aOverlap, 0, sizeof(aOverlap));
+  while( pThisEvent ){
+    if( pThisEvent->x!=rX ){
+      GeoSegment *pPrev = 0;
+      int iMask = 0;
+      GEODEBUG(("Distinct X: %g\n", pThisEvent->x));
+      rX = pThisEvent->x;
+      if( needSort ){
+        GEODEBUG(("SORT\n"));
+        pActive = geopolySortSegmentsByYAndC(pActive);
+        needSort = 0;
+      }
+      for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
+        if( pPrev ){
+          if( pPrev->y!=pSeg->y ){
+            GEODEBUG(("MASK: %d\n", iMask));
+            aOverlap[iMask] = 1;
+          }
+        }
+        iMask ^= pSeg->side;
+        pPrev = pSeg;
+      }
+      pPrev = 0;
+      for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
+        double y = pSeg->C*rX + pSeg->B;
+        GEODEBUG(("Segment %d.%d %g->%g\n", pSeg->side, pSeg->idx, pSeg->y, y));
+        pSeg->y = y;
+        if( pPrev ){
+          if( pPrev->y>pSeg->y && pPrev->side!=pSeg->side ){
+            rc = 1;
+            GEODEBUG(("Crossing: %d.%d and %d.%d\n",
+                    pPrev->side, pPrev->idx,
+                    pSeg->side, pSeg->idx));
+            goto geopolyOverlapDone;
+          }else if( pPrev->y!=pSeg->y ){
+            GEODEBUG(("MASK: %d\n", iMask));
+            aOverlap[iMask] = 1;
+          }
+        }
+        iMask ^= pSeg->side;
+        pPrev = pSeg;
+      }
+    }
+    GEODEBUG(("%s %d.%d C=%g B=%g\n",
+      pThisEvent->eType ? "RM " : "ADD",
+      pThisEvent->pSeg->side, pThisEvent->pSeg->idx,
+      pThisEvent->pSeg->C,
+      pThisEvent->pSeg->B));
+    if( pThisEvent->eType==0 ){
+      /* Add a segment */
+      pSeg = pThisEvent->pSeg;
+      pSeg->y = pSeg->y0;
+      pSeg->pNext = pActive;
+      pActive = pSeg;
+      needSort = 1;
+    }else{
+      /* Remove a segment */
+      if( pActive==pThisEvent->pSeg ){
+        pActive = ALWAYS(pActive) ? pActive->pNext : 0;
+      }else{
+        for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
+          if( pSeg->pNext==pThisEvent->pSeg ){
+            pSeg->pNext = ALWAYS(pSeg->pNext) ? pSeg->pNext->pNext : 0;
+            break;
+          }
+        }
+      }
+    }
+    pThisEvent = pThisEvent->pNext;
+  }
+  if( aOverlap[3]==0 ){
+    rc = 0;
+  }else if( aOverlap[1]!=0 && aOverlap[2]==0 ){
+    rc = 3;
+  }else if( aOverlap[1]==0 && aOverlap[2]!=0 ){
+    rc = 2;
+  }else if( aOverlap[1]==0 && aOverlap[2]==0 ){
+    rc = 4;
+  }else{
+    rc = 1;
+  }
+
+geopolyOverlapDone:
+  sqlite3_free(p);
+  return rc;
+}
+
+/*
+** SQL function:    geopoly_overlap(P1,P2)
+**
+** Determine whether or not P1 and P2 overlap. Return value:
+**
+**   0     The two polygons are disjoint
+**   1     They overlap
+**   2     P1 is completely contained within P2
+**   3     P2 is completely contained within P1
+**   4     P1 and P2 are the same polygon
+**   NULL  Either P1 or P2 or both are not valid polygons
+*/
+static void geopolyOverlapFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p1 = geopolyFuncParam(context, argv[0], 0);
+  GeoPoly *p2 = geopolyFuncParam(context, argv[1], 0);
+  (void)argc;
+  if( p1 && p2 ){
+    int x = geopolyOverlap(p1, p2);
+    if( x<0 ){
+      sqlite3_result_error_nomem(context);
+    }else{
+      sqlite3_result_int(context, x);
+    }
+  }
+  sqlite3_free(p1);
+  sqlite3_free(p2);
+}
+
+/*
+** Enable or disable debugging output
+*/
+static void geopolyDebugFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  (void)context;
+  (void)argc;
+#ifdef GEOPOLY_ENABLE_DEBUG
+  geo_debug = sqlite3_value_int(argv[0]);
+#else
+  (void)argv;
+#endif
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the geopoly virtual table.
+**
+**   argv[0]   -> module name
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> column names...
+*/
+static int geopolyInit(
+  sqlite3 *db,                        /* Database connection */
+  void *pAux,                         /* One of the RTREE_COORD_* constants */
+  int argc, const char *const*argv,   /* Parameters to CREATE TABLE statement */
+  sqlite3_vtab **ppVtab,              /* OUT: New virtual table */
+  char **pzErr,                       /* OUT: Error message, if any */
+  int isCreate                        /* True for xCreate, false for xConnect */
+){
+  int rc = SQLITE_OK;
+  Rtree *pRtree;
+  sqlite3_int64 nDb;              /* Length of string argv[1] */
+  sqlite3_int64 nName;            /* Length of string argv[2] */
+  sqlite3_str *pSql;
+  char *zSql;
+  int ii;
+  (void)pAux;
+
+  sqlite3_vtab_config(db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1);
+  sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
+
+  /* Allocate the sqlite3_vtab structure */
+  nDb = strlen(argv[1]);
+  nName = strlen(argv[2]);
+  pRtree = (Rtree *)sqlite3_malloc64(sizeof(Rtree)+nDb+nName*2+8);
+  if( !pRtree ){
+    return SQLITE_NOMEM;
+  }
+  memset(pRtree, 0, sizeof(Rtree)+nDb+nName*2+8);
+  pRtree->nBusy = 1;
+  pRtree->base.pModule = &rtreeModule;
+  pRtree->zDb = (char *)&pRtree[1];
+  pRtree->zName = &pRtree->zDb[nDb+1];
+  pRtree->zNodeName = &pRtree->zName[nName+1];
+  pRtree->eCoordType = RTREE_COORD_REAL32;
+  pRtree->nDim = 2;
+  pRtree->nDim2 = 4;
+  memcpy(pRtree->zDb, argv[1], nDb);
+  memcpy(pRtree->zName, argv[2], nName);
+  memcpy(pRtree->zNodeName, argv[2], nName);
+  memcpy(&pRtree->zNodeName[nName], "_node", 6);
+
+
+  /* Create/Connect to the underlying relational database schema. If
+  ** that is successful, call sqlite3_declare_vtab() to configure
+  ** the r-tree table schema.
+  */
+  pSql = sqlite3_str_new(db);
+  sqlite3_str_appendf(pSql, "CREATE TABLE x(_shape");
+  pRtree->nAux = 1;         /* Add one for _shape */
+  pRtree->nAuxNotNull = 1;  /* The _shape column is always not-null */
+  for(ii=3; ii<argc; ii++){
+    pRtree->nAux++;
+    sqlite3_str_appendf(pSql, ",%s", argv[ii]);
+  }
+  sqlite3_str_appendf(pSql, ");");
+  zSql = sqlite3_str_finish(pSql);
+  if( !zSql ){
+    rc = SQLITE_NOMEM;
+  }else if( SQLITE_OK!=(rc = sqlite3_declare_vtab(db, zSql)) ){
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+  }
+  sqlite3_free(zSql);
+  if( rc ) goto geopolyInit_fail;
+  pRtree->nBytesPerCell = 8 + pRtree->nDim2*4;
+
+  /* Figure out the node size to use. */
+  rc = getNodeSize(db, pRtree, isCreate, pzErr);
+  if( rc ) goto geopolyInit_fail;
+  rc = rtreeSqlInit(pRtree, db, argv[1], argv[2], isCreate);
+  if( rc ){
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    goto geopolyInit_fail;
+  }
+
+  *ppVtab = (sqlite3_vtab *)pRtree;
+  return SQLITE_OK;
+
+geopolyInit_fail:
+  if( rc==SQLITE_OK ) rc = SQLITE_ERROR;
+  assert( *ppVtab==0 );
+  assert( pRtree->nBusy==1 );
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+
+/*
+** GEOPOLY virtual table module xCreate method.
+*/
+static int geopolyCreate(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  return geopolyInit(db, pAux, argc, argv, ppVtab, pzErr, 1);
+}
+
+/*
+** GEOPOLY virtual table module xConnect method.
+*/
+static int geopolyConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  return geopolyInit(db, pAux, argc, argv, ppVtab, pzErr, 0);
+}
+
+
+/*
+** GEOPOLY virtual table module xFilter method.
+**
+** Query plans:
+**
+**      1         rowid lookup
+**      2         search for objects overlapping the same bounding box
+**                that contains polygon argv[0]
+**      3         search for objects overlapping the same bounding box
+**                that contains polygon argv[0]
+**      4         full table scan
+*/
+static int geopolyFilter(
+  sqlite3_vtab_cursor *pVtabCursor,     /* The cursor to initialize */
+  int idxNum,                           /* Query plan */
+  const char *idxStr,                   /* Not Used */
+  int argc, sqlite3_value **argv        /* Parameters to the query plan */
+){
+  Rtree *pRtree = (Rtree *)pVtabCursor->pVtab;
+  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+  RtreeNode *pRoot = 0;
+  int rc = SQLITE_OK;
+  int iCell = 0;
+  (void)idxStr;
+
+  rtreeReference(pRtree);
+
+  /* Reset the cursor to the same state as rtreeOpen() leaves it in. */
+  resetCursor(pCsr);
+
+  pCsr->iStrategy = idxNum;
+  if( idxNum==1 ){
+    /* Special case - lookup by rowid. */
+    RtreeNode *pLeaf;        /* Leaf on which the required cell resides */
+    RtreeSearchPoint *p;     /* Search point for the leaf */
+    i64 iRowid = sqlite3_value_int64(argv[0]);
+    i64 iNode = 0;
+    rc = findLeafNode(pRtree, iRowid, &pLeaf, &iNode);
+    if( rc==SQLITE_OK && pLeaf!=0 ){
+      p = rtreeSearchPointNew(pCsr, RTREE_ZERO, 0);
+      assert( p!=0 );  /* Always returns pCsr->sPoint */
+      pCsr->aNode[0] = pLeaf;
+      p->id = iNode;
+      p->eWithin = PARTLY_WITHIN;
+      rc = nodeRowidIndex(pRtree, pLeaf, iRowid, &iCell);
+      p->iCell = (u8)iCell;
+      RTREE_QUEUE_TRACE(pCsr, "PUSH-F1:");
+    }else{
+      pCsr->atEOF = 1;
+    }
+  }else{
+    /* Normal case - r-tree scan. Set up the RtreeCursor.aConstraint array
+    ** with the configured constraints.
+    */
+    rc = nodeAcquire(pRtree, 1, 0, &pRoot);
+    if( rc==SQLITE_OK && idxNum<=3 ){
+      RtreeCoord bbox[4];
+      RtreeConstraint *p;
+      assert( argc==1 );
+      assert( argv[0]!=0 );
+      geopolyBBox(0, argv[0], bbox, &rc);
+      if( rc ){
+        goto geopoly_filter_end;
+      }
+      pCsr->aConstraint = p = sqlite3_malloc(sizeof(RtreeConstraint)*4);
+      pCsr->nConstraint = 4;
+      if( p==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(pCsr->aConstraint, 0, sizeof(RtreeConstraint)*4);
+        memset(pCsr->anQueue, 0, sizeof(u32)*(pRtree->iDepth + 1));
+        if( idxNum==2 ){
+          /* Overlap query */
+          p->op = 'B';
+          p->iCoord = 0;
+          p->u.rValue = bbox[1].f;
+          p++;
+          p->op = 'D';
+          p->iCoord = 1;
+          p->u.rValue = bbox[0].f;
+          p++;
+          p->op = 'B';
+          p->iCoord = 2;
+          p->u.rValue = bbox[3].f;
+          p++;
+          p->op = 'D';
+          p->iCoord = 3;
+          p->u.rValue = bbox[2].f;
+        }else{
+          /* Within query */
+          p->op = 'D';
+          p->iCoord = 0;
+          p->u.rValue = bbox[0].f;
+          p++;
+          p->op = 'B';
+          p->iCoord = 1;
+          p->u.rValue = bbox[1].f;
+          p++;
+          p->op = 'D';
+          p->iCoord = 2;
+          p->u.rValue = bbox[2].f;
+          p++;
+          p->op = 'B';
+          p->iCoord = 3;
+          p->u.rValue = bbox[3].f;
+        }
+      }
+    }
+    if( rc==SQLITE_OK ){
+      RtreeSearchPoint *pNew;
+      pNew = rtreeSearchPointNew(pCsr, RTREE_ZERO, (u8)(pRtree->iDepth+1));
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM;
+        goto geopoly_filter_end;
+      }
+      pNew->id = 1;
+      pNew->iCell = 0;
+      pNew->eWithin = PARTLY_WITHIN;
+      assert( pCsr->bPoint==1 );
+      pCsr->aNode[0] = pRoot;
+      pRoot = 0;
+      RTREE_QUEUE_TRACE(pCsr, "PUSH-Fm:");
+      rc = rtreeStepToLeaf(pCsr);
+    }
+  }
+
+geopoly_filter_end:
+  nodeRelease(pRtree, pRoot);
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+/*
+** Rtree virtual table module xBestIndex method. There are three
+** table scan strategies to choose from (in order from most to
+** least desirable):
+**
+**   idxNum     idxStr        Strategy
+**   ------------------------------------------------
+**     1        "rowid"       Direct lookup by rowid.
+**     2        "rtree"       R-tree overlap query using geopoly_overlap()
+**     3        "rtree"       R-tree within query using geopoly_within()
+**     4        "fullscan"    full-table scan.
+**   ------------------------------------------------
+*/
+static int geopolyBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  int ii;
+  int iRowidTerm = -1;
+  int iFuncTerm = -1;
+  int idxNum = 0;
+  (void)tab;
+
+  for(ii=0; ii<pIdxInfo->nConstraint; ii++){
+    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[ii];
+    if( !p->usable ) continue;
+    if( p->iColumn<0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ  ){
+      iRowidTerm = ii;
+      break;
+    }
+    if( p->iColumn==0 && p->op>=SQLITE_INDEX_CONSTRAINT_FUNCTION ){
+      /* p->op==SQLITE_INDEX_CONSTRAINT_FUNCTION for geopoly_overlap()
+      ** p->op==(SQLITE_INDEX_CONTRAINT_FUNCTION+1) for geopoly_within().
+      ** See geopolyFindFunction() */
+      iFuncTerm = ii;
+      idxNum = p->op - SQLITE_INDEX_CONSTRAINT_FUNCTION + 2;
+    }
+  }
+
+  if( iRowidTerm>=0 ){
+    pIdxInfo->idxNum = 1;
+    pIdxInfo->idxStr = "rowid";
+    pIdxInfo->aConstraintUsage[iRowidTerm].argvIndex = 1;
+    pIdxInfo->aConstraintUsage[iRowidTerm].omit = 1;
+    pIdxInfo->estimatedCost = 30.0;
+    pIdxInfo->estimatedRows = 1;
+    pIdxInfo->idxFlags = SQLITE_INDEX_SCAN_UNIQUE;
+    return SQLITE_OK;
+  }
+  if( iFuncTerm>=0 ){
+    pIdxInfo->idxNum = idxNum;
+    pIdxInfo->idxStr = "rtree";
+    pIdxInfo->aConstraintUsage[iFuncTerm].argvIndex = 1;
+    pIdxInfo->aConstraintUsage[iFuncTerm].omit = 0;
+    pIdxInfo->estimatedCost = 300.0;
+    pIdxInfo->estimatedRows = 10;
+    return SQLITE_OK;
+  }
+  pIdxInfo->idxNum = 4;
+  pIdxInfo->idxStr = "fullscan";
+  pIdxInfo->estimatedCost = 3000000.0;
+  pIdxInfo->estimatedRows = 100000;
+  return SQLITE_OK;
+}
+
+
+/*
+** GEOPOLY virtual table module xColumn method.
+*/
+static int geopolyColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
+  Rtree *pRtree = (Rtree *)cur->pVtab;
+  RtreeCursor *pCsr = (RtreeCursor *)cur;
+  RtreeSearchPoint *p = rtreeSearchPointFirst(pCsr);
+  int rc = SQLITE_OK;
+  RtreeNode *pNode = rtreeNodeOfFirstSearchPoint(pCsr, &rc);
+
+  if( rc ) return rc;
+  if( p==0 ) return SQLITE_OK;
+  if( i==0 && sqlite3_vtab_nochange(ctx) ) return SQLITE_OK;
+  if( i<=pRtree->nAux ){
+    if( !pCsr->bAuxValid ){
+      if( pCsr->pReadAux==0 ){
+        rc = sqlite3_prepare_v3(pRtree->db, pRtree->zReadAuxSql, -1, 0,
+                                &pCsr->pReadAux, 0);
+        if( rc ) return rc;
+      }
+      sqlite3_bind_int64(pCsr->pReadAux, 1,
+          nodeGetRowid(pRtree, pNode, p->iCell));
+      rc = sqlite3_step(pCsr->pReadAux);
+      if( rc==SQLITE_ROW ){
+        pCsr->bAuxValid = 1;
+      }else{
+        sqlite3_reset(pCsr->pReadAux);
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+        return rc;
+      }
+    }
+    sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pReadAux, i+2));
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** The xUpdate method for GEOPOLY module virtual tables.
+**
+** For DELETE:
+**
+**     argv[0] = the rowid to be deleted
+**
+** For INSERT:
+**
+**     argv[0] = SQL NULL
+**     argv[1] = rowid to insert, or an SQL NULL to select automatically
+**     argv[2] = _shape column
+**     argv[3] = first application-defined column....
+**
+** For UPDATE:
+**
+**     argv[0] = rowid to modify.  Never NULL
+**     argv[1] = rowid after the change.  Never NULL
+**     argv[2] = new value for _shape
+**     argv[3] = new value for first application-defined column....
+*/
+static int geopolyUpdate(
+  sqlite3_vtab *pVtab,
+  int nData,
+  sqlite3_value **aData,
+  sqlite_int64 *pRowid
+){
+  Rtree *pRtree = (Rtree *)pVtab;
+  int rc = SQLITE_OK;
+  RtreeCell cell;                 /* New cell to insert if nData>1 */
+  i64 oldRowid;                   /* The old rowid */
+  int oldRowidValid;              /* True if oldRowid is valid */
+  i64 newRowid;                   /* The new rowid */
+  int newRowidValid;              /* True if newRowid is valid */
+  int coordChange = 0;            /* Change in coordinates */
+
+  if( pRtree->nNodeRef ){
+    /* Unable to write to the btree while another cursor is reading from it,
+    ** since the write might do a rebalance which would disrupt the read
+    ** cursor. */
+    return SQLITE_LOCKED_VTAB;
+  }
+  rtreeReference(pRtree);
+  assert(nData>=1);
+
+  oldRowidValid = sqlite3_value_type(aData[0])!=SQLITE_NULL;;
+  oldRowid = oldRowidValid ? sqlite3_value_int64(aData[0]) : 0;
+  newRowidValid = nData>1 && sqlite3_value_type(aData[1])!=SQLITE_NULL;
+  newRowid = newRowidValid ? sqlite3_value_int64(aData[1]) : 0;
+  cell.iRowid = newRowid;
+
+  if( nData>1                                 /* not a DELETE */
+   && (!oldRowidValid                         /* INSERT */
+        || !sqlite3_value_nochange(aData[2])  /* UPDATE _shape */
+        || oldRowid!=newRowid)                /* Rowid change */
+  ){
+    assert( aData[2]!=0 );
+    geopolyBBox(0, aData[2], cell.aCoord, &rc);
+    if( rc ){
+      if( rc==SQLITE_ERROR ){
+        pVtab->zErrMsg =
+          sqlite3_mprintf("_shape does not contain a valid polygon");
+      }
+      goto geopoly_update_end;
+    }
+    coordChange = 1;
+
+    /* If a rowid value was supplied, check if it is already present in
+    ** the table. If so, the constraint has failed. */
+    if( newRowidValid && (!oldRowidValid || oldRowid!=newRowid) ){
+      int steprc;
+      sqlite3_bind_int64(pRtree->pReadRowid, 1, cell.iRowid);
+      steprc = sqlite3_step(pRtree->pReadRowid);
+      rc = sqlite3_reset(pRtree->pReadRowid);
+      if( SQLITE_ROW==steprc ){
+        if( sqlite3_vtab_on_conflict(pRtree->db)==SQLITE_REPLACE ){
+          rc = rtreeDeleteRowid(pRtree, cell.iRowid);
+        }else{
+          rc = rtreeConstraintError(pRtree, 0);
+        }
+      }
+    }
+  }
+
+  /* If aData[0] is not an SQL NULL value, it is the rowid of a
+  ** record to delete from the r-tree table. The following block does
+  ** just that.
+  */
+  if( rc==SQLITE_OK && (nData==1 || (coordChange && oldRowidValid)) ){
+    rc = rtreeDeleteRowid(pRtree, oldRowid);
+  }
+
+  /* If the aData[] array contains more than one element, elements
+  ** (aData[2]..aData[argc-1]) contain a new record to insert into
+  ** the r-tree structure.
+  */
+  if( rc==SQLITE_OK && nData>1 && coordChange ){
+    /* Insert the new record into the r-tree */
+    RtreeNode *pLeaf = 0;
+    if( !newRowidValid ){
+      rc = rtreeNewRowid(pRtree, &cell.iRowid);
+    }
+    *pRowid = cell.iRowid;
+    if( rc==SQLITE_OK ){
+      rc = ChooseLeaf(pRtree, &cell, 0, &pLeaf);
+    }
+    if( rc==SQLITE_OK ){
+      int rc2;
+      rc = rtreeInsertCell(pRtree, pLeaf, &cell, 0);
+      rc2 = nodeRelease(pRtree, pLeaf);
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+  }
+
+  /* Change the data */
+  if( rc==SQLITE_OK && nData>1 ){
+    sqlite3_stmt *pUp = pRtree->pWriteAux;
+    int jj;
+    int nChange = 0;
+    sqlite3_bind_int64(pUp, 1, cell.iRowid);
+    assert( pRtree->nAux>=1 );
+    if( sqlite3_value_nochange(aData[2]) ){
+      sqlite3_bind_null(pUp, 2);
+    }else{
+      GeoPoly *p = 0;
+      if( sqlite3_value_type(aData[2])==SQLITE_TEXT
+       && (p = geopolyFuncParam(0, aData[2], &rc))!=0
+       && rc==SQLITE_OK
+      ){
+        sqlite3_bind_blob(pUp, 2, p->hdr, 4+8*p->nVertex, SQLITE_TRANSIENT);
+      }else{
+        sqlite3_bind_value(pUp, 2, aData[2]);
+      }
+      sqlite3_free(p);
+      nChange = 1;
+    }
+    for(jj=1; jj<nData-2; jj++){
+      nChange++;
+      sqlite3_bind_value(pUp, jj+2, aData[jj+2]);
+    }
+    if( nChange ){
+      sqlite3_step(pUp);
+      rc = sqlite3_reset(pUp);
+    }
+  }
+
+geopoly_update_end:
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+/*
+** Report that geopoly_overlap() is an overloaded function suitable
+** for use in xBestIndex.
+*/
+static int geopolyFindFunction(
+  sqlite3_vtab *pVtab,
+  int nArg,
+  const char *zName,
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
+  void **ppArg
+){
+  (void)pVtab;
+  (void)nArg;
+  if( sqlite3_stricmp(zName, "geopoly_overlap")==0 ){
+    *pxFunc = geopolyOverlapFunc;
+    *ppArg = 0;
+    return SQLITE_INDEX_CONSTRAINT_FUNCTION;
+  }
+  if( sqlite3_stricmp(zName, "geopoly_within")==0 ){
+    *pxFunc = geopolyWithinFunc;
+    *ppArg = 0;
+    return SQLITE_INDEX_CONSTRAINT_FUNCTION+1;
+  }
+  return 0;
+}
+
+
+static sqlite3_module geopolyModule = {
+  3,                          /* iVersion */
+  geopolyCreate,              /* xCreate - create a table */
+  geopolyConnect,             /* xConnect - connect to an existing table */
+  geopolyBestIndex,           /* xBestIndex - Determine search strategy */
+  rtreeDisconnect,            /* xDisconnect - Disconnect from a table */
+  rtreeDestroy,               /* xDestroy - Drop a table */
+  rtreeOpen,                  /* xOpen - open a cursor */
+  rtreeClose,                 /* xClose - close a cursor */
+  geopolyFilter,              /* xFilter - configure scan constraints */
+  rtreeNext,                  /* xNext - advance a cursor */
+  rtreeEof,                   /* xEof */
+  geopolyColumn,              /* xColumn - read data */
+  rtreeRowid,                 /* xRowid - read data */
+  geopolyUpdate,              /* xUpdate - write data */
+  rtreeBeginTransaction,      /* xBegin - begin transaction */
+  rtreeEndTransaction,        /* xSync - sync transaction */
+  rtreeEndTransaction,        /* xCommit - commit transaction */
+  rtreeEndTransaction,        /* xRollback - rollback transaction */
+  geopolyFindFunction,        /* xFindFunction - function overloading */
+  rtreeRename,                /* xRename - rename the table */
+  rtreeSavepoint,             /* xSavepoint */
+  0,                          /* xRelease */
+  0,                          /* xRollbackTo */
+  rtreeShadowName,            /* xShadowName */
+  rtreeIntegrity              /* xIntegrity */
+};
+
+static int sqlite3_geopoly_init(sqlite3 *db){
+  int rc = SQLITE_OK;
+  static const struct {
+    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+    signed char nArg;
+    unsigned char bPure;
+    const char *zName;
+  } aFunc[] = {
+     { geopolyAreaFunc,          1, 1,    "geopoly_area"             },
+     { geopolyBlobFunc,          1, 1,    "geopoly_blob"             },
+     { geopolyJsonFunc,          1, 1,    "geopoly_json"             },
+     { geopolySvgFunc,          -1, 1,    "geopoly_svg"              },
+     { geopolyWithinFunc,        2, 1,    "geopoly_within"           },
+     { geopolyContainsPointFunc, 3, 1,    "geopoly_contains_point"   },
+     { geopolyOverlapFunc,       2, 1,    "geopoly_overlap"          },
+     { geopolyDebugFunc,         1, 0,    "geopoly_debug"            },
+     { geopolyBBoxFunc,          1, 1,    "geopoly_bbox"             },
+     { geopolyXformFunc,         7, 1,    "geopoly_xform"            },
+     { geopolyRegularFunc,       4, 1,    "geopoly_regular"          },
+     { geopolyCcwFunc,           1, 1,    "geopoly_ccw"              },
+  };
+  static const struct {
+    void (*xStep)(sqlite3_context*,int,sqlite3_value**);
+    void (*xFinal)(sqlite3_context*);
+    const char *zName;
+  } aAgg[] = {
+     { geopolyBBoxStep, geopolyBBoxFinal, "geopoly_group_bbox"    },
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(aFunc)/sizeof(aFunc[0]) && rc==SQLITE_OK; i++){
+    int enc;
+    if( aFunc[i].bPure ){
+      enc = SQLITE_UTF8|SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS;
+    }else{
+      enc = SQLITE_UTF8|SQLITE_DIRECTONLY;
+    }
+    rc = sqlite3_create_function(db, aFunc[i].zName, aFunc[i].nArg,
+                                 enc, 0,
+                                 aFunc[i].xFunc, 0, 0);
+  }
+  for(i=0; i<sizeof(aAgg)/sizeof(aAgg[0]) && rc==SQLITE_OK; i++){
+    rc = sqlite3_create_function(db, aAgg[i].zName, 1,
+              SQLITE_UTF8|SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS, 0,
+              0, aAgg[i].xStep, aAgg[i].xFinal);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_module_v2(db, "geopoly", &geopolyModule, 0, 0);
+  }
+  return rc;
+}
+
+/************** End of geopoly.c *********************************************/
+/************** Continuing where we left off in rtree.c **********************/
+#endif
+
+/*
+** Register the r-tree module with database handle db. This creates the
+** virtual table module "rtree" and the debugging/analysis scalar
+** function "rtreenode".
+*/
+SQLITE_PRIVATE int sqlite3RtreeInit(sqlite3 *db){
+  const int utf8 = SQLITE_UTF8;
+  int rc;
+
+  rc = sqlite3_create_function(db, "rtreenode", 2, utf8, 0, rtreenode, 0, 0);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(db, "rtreedepth", 1, utf8, 0,rtreedepth, 0, 0);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(db, "rtreecheck", -1, utf8, 0,rtreecheck, 0,0);
+  }
+  if( rc==SQLITE_OK ){
+#ifdef SQLITE_RTREE_INT_ONLY
+    void *c = (void *)RTREE_COORD_INT32;
+#else
+    void *c = (void *)RTREE_COORD_REAL32;
+#endif
+    rc = sqlite3_create_module_v2(db, "rtree", &rtreeModule, c, 0);
+  }
+  if( rc==SQLITE_OK ){
+    void *c = (void *)RTREE_COORD_INT32;
+    rc = sqlite3_create_module_v2(db, "rtree_i32", &rtreeModule, c, 0);
+  }
+#ifdef SQLITE_ENABLE_GEOPOLY
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_geopoly_init(db);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** This routine deletes the RtreeGeomCallback object that was attached
+** one of the SQL functions create by sqlite3_rtree_geometry_callback()
+** or sqlite3_rtree_query_callback().  In other words, this routine is the
+** destructor for an RtreeGeomCallback objecct.  This routine is called when
+** the corresponding SQL function is deleted.
+*/
+static void rtreeFreeCallback(void *p){
+  RtreeGeomCallback *pInfo = (RtreeGeomCallback*)p;
+  if( pInfo->xDestructor ) pInfo->xDestructor(pInfo->pContext);
+  sqlite3_free(p);
+}
+
+/*
+** This routine frees the BLOB that is returned by geomCallback().
+*/
+static void rtreeMatchArgFree(void *pArg){
+  int i;
+  RtreeMatchArg *p = (RtreeMatchArg*)pArg;
+  for(i=0; i<p->nParam; i++){
+    sqlite3_value_free(p->apSqlParam[i]);
+  }
+  sqlite3_free(p);
+}
+
+/*
+** Each call to sqlite3_rtree_geometry_callback() or
+** sqlite3_rtree_query_callback() creates an ordinary SQLite
+** scalar function that is implemented by this routine.
+**
+** All this function does is construct an RtreeMatchArg object that
+** contains the geometry-checking callback routines and a list of
+** parameters to this function, then return that RtreeMatchArg object
+** as a BLOB.
+**
+** The R-Tree MATCH operator will read the returned BLOB, deserialize
+** the RtreeMatchArg object, and use the RtreeMatchArg object to figure
+** out which elements of the R-Tree should be returned by the query.
+*/
+static void geomCallback(sqlite3_context *ctx, int nArg, sqlite3_value **aArg){
+  RtreeGeomCallback *pGeomCtx = (RtreeGeomCallback *)sqlite3_user_data(ctx);
+  RtreeMatchArg *pBlob;
+  sqlite3_int64 nBlob;
+  int memErr = 0;
+
+  nBlob = sizeof(RtreeMatchArg) + (nArg-1)*sizeof(RtreeDValue)
+           + nArg*sizeof(sqlite3_value*);
+  pBlob = (RtreeMatchArg *)sqlite3_malloc64(nBlob);
+  if( !pBlob ){
+    sqlite3_result_error_nomem(ctx);
+  }else{
+    int i;
+    pBlob->iSize = nBlob;
+    pBlob->cb = pGeomCtx[0];
+    pBlob->apSqlParam = (sqlite3_value**)&pBlob->aParam[nArg];
+    pBlob->nParam = nArg;
+    for(i=0; i<nArg; i++){
+      pBlob->apSqlParam[i] = sqlite3_value_dup(aArg[i]);
+      if( pBlob->apSqlParam[i]==0 ) memErr = 1;
+#ifdef SQLITE_RTREE_INT_ONLY
+      pBlob->aParam[i] = sqlite3_value_int64(aArg[i]);
+#else
+      pBlob->aParam[i] = sqlite3_value_double(aArg[i]);
+#endif
+    }
+    if( memErr ){
+      sqlite3_result_error_nomem(ctx);
+      rtreeMatchArgFree(pBlob);
+    }else{
+      sqlite3_result_pointer(ctx, pBlob, "RtreeMatchArg", rtreeMatchArgFree);
+    }
+  }
+}
+
+/*
+** Register a new geometry function for use with the r-tree MATCH operator.
+*/
+SQLITE_API int sqlite3_rtree_geometry_callback(
+  sqlite3 *db,                  /* Register SQL function on this connection */
+  const char *zGeom,            /* Name of the new SQL function */
+  int (*xGeom)(sqlite3_rtree_geometry*,int,RtreeDValue*,int*), /* Callback */
+  void *pContext                /* Extra data associated with the callback */
+){
+  RtreeGeomCallback *pGeomCtx;      /* Context object for new user-function */
+
+  /* Allocate and populate the context object. */
+  pGeomCtx = (RtreeGeomCallback *)sqlite3_malloc(sizeof(RtreeGeomCallback));
+  if( !pGeomCtx ) return SQLITE_NOMEM;
+  pGeomCtx->xGeom = xGeom;
+  pGeomCtx->xQueryFunc = 0;
+  pGeomCtx->xDestructor = 0;
+  pGeomCtx->pContext = pContext;
+  return sqlite3_create_function_v2(db, zGeom, -1, SQLITE_ANY,
+      (void *)pGeomCtx, geomCallback, 0, 0, rtreeFreeCallback
+  );
+}
+
+/*
+** Register a new 2nd-generation geometry function for use with the
+** r-tree MATCH operator.
+*/
+SQLITE_API int sqlite3_rtree_query_callback(
+  sqlite3 *db,                 /* Register SQL function on this connection */
+  const char *zQueryFunc,      /* Name of new SQL function */
+  int (*xQueryFunc)(sqlite3_rtree_query_info*), /* Callback */
+  void *pContext,              /* Extra data passed into the callback */
+  void (*xDestructor)(void*)   /* Destructor for the extra data */
+){
+  RtreeGeomCallback *pGeomCtx;      /* Context object for new user-function */
+
+  /* Allocate and populate the context object. */
+  pGeomCtx = (RtreeGeomCallback *)sqlite3_malloc(sizeof(RtreeGeomCallback));
+  if( !pGeomCtx ){
+    if( xDestructor ) xDestructor(pContext);
+    return SQLITE_NOMEM;
+  }
+  pGeomCtx->xGeom = 0;
+  pGeomCtx->xQueryFunc = xQueryFunc;
+  pGeomCtx->xDestructor = xDestructor;
+  pGeomCtx->pContext = pContext;
+  return sqlite3_create_function_v2(db, zQueryFunc, -1, SQLITE_ANY,
+      (void *)pGeomCtx, geomCallback, 0, 0, rtreeFreeCallback
+  );
+}
+
+#ifndef SQLITE_CORE
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_rtree_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi)
+  return sqlite3RtreeInit(db);
+}
+#endif
+
+#endif
+
+/************** End of rtree.c ***********************************************/
+/************** Begin file icu.c *********************************************/
+/*
+** 2007 May 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** $Id: icu.c,v 1.7 2007/12/13 21:54:11 drh Exp $
+**
+** This file implements an integration between the ICU library
+** ("International Components for Unicode", an open-source library
+** for handling unicode data) and SQLite. The integration uses
+** ICU to provide the following to SQLite:
+**
+**   * An implementation of the SQL regexp() function (and hence REGEXP
+**     operator) using the ICU uregex_XX() APIs.
+**
+**   * Implementations of the SQL scalar upper() and lower() functions
+**     for case mapping.
+**
+**   * Integration of ICU and SQLite collation sequences.
+**
+**   * An implementation of the LIKE operator that uses ICU to
+**     provide case-independent matching.
+*/
+
+#if !defined(SQLITE_CORE)                  \
+ || defined(SQLITE_ENABLE_ICU)             \
+ || defined(SQLITE_ENABLE_ICU_COLLATIONS)
+
+/* Include ICU headers */
+#include <unicode/utypes.h>
+#include <unicode/uregex.h>
+#include <unicode/ustring.h>
+#include <unicode/ucol.h>
+
+/* #include <assert.h> */
+
+#ifndef SQLITE_CORE
+/*   #include "sqlite3ext.h" */
+  SQLITE_EXTENSION_INIT1
+#else
+/*   #include "sqlite3.h" */
+#endif
+
+/*
+** This function is called when an ICU function called from within
+** the implementation of an SQL scalar function returns an error.
+**
+** The scalar function context passed as the first argument is
+** loaded with an error message based on the following two args.
+*/
+static void icuFunctionError(
+  sqlite3_context *pCtx,       /* SQLite scalar function context */
+  const char *zName,           /* Name of ICU function that failed */
+  UErrorCode e                 /* Error code returned by ICU function */
+){
+  char zBuf[128];
+  sqlite3_snprintf(128, zBuf, "ICU error: %s(): %s", zName, u_errorName(e));
+  zBuf[127] = '\0';
+  sqlite3_result_error(pCtx, zBuf, -1);
+}
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_ICU)
+
+/*
+** Maximum length (in bytes) of the pattern in a LIKE or GLOB
+** operator.
+*/
+#ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
+# define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
+#endif
+
+/*
+** Version of sqlite3_free() that is always a function, never a macro.
+*/
+static void xFree(void *p){
+  sqlite3_free(p);
+}
+
+/*
+** This lookup table is used to help decode the first byte of
+** a multi-byte UTF8 character. It is copied here from SQLite source
+** code file utf8.c.
+*/
+static const unsigned char icuUtf8Trans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+#define SQLITE_ICU_READ_UTF8(zIn, c)                       \
+  c = *(zIn++);                                            \
+  if( c>=0xc0 ){                                           \
+    c = icuUtf8Trans1[c-0xc0];                             \
+    while( (*zIn & 0xc0)==0x80 ){                          \
+      c = (c<<6) + (0x3f & *(zIn++));                      \
+    }                                                      \
+  }
+
+#define SQLITE_ICU_SKIP_UTF8(zIn)                          \
+  assert( *zIn );                                          \
+  if( *(zIn++)>=0xc0 ){                                    \
+    while( (*zIn & 0xc0)==0x80 ){zIn++;}                   \
+  }
+
+
+/*
+** Compare two UTF-8 strings for equality where the first string is
+** a "LIKE" expression. Return true (1) if they are the same and
+** false (0) if they are different.
+*/
+static int icuLikeCompare(
+  const uint8_t *zPattern,   /* LIKE pattern */
+  const uint8_t *zString,    /* The UTF-8 string to compare against */
+  const UChar32 uEsc         /* The escape character */
+){
+  static const uint32_t MATCH_ONE = (uint32_t)'_';
+  static const uint32_t MATCH_ALL = (uint32_t)'%';
+
+  int prevEscape = 0;     /* True if the previous character was uEsc */
+
+  while( 1 ){
+
+    /* Read (and consume) the next character from the input pattern. */
+    uint32_t uPattern;
+    SQLITE_ICU_READ_UTF8(zPattern, uPattern);
+    if( uPattern==0 ) break;
+
+    /* There are now 4 possibilities:
+    **
+    **     1. uPattern is an unescaped match-all character "%",
+    **     2. uPattern is an unescaped match-one character "_",
+    **     3. uPattern is an unescaped escape character, or
+    **     4. uPattern is to be handled as an ordinary character
+    */
+    if( uPattern==MATCH_ALL && !prevEscape && uPattern!=(uint32_t)uEsc ){
+      /* Case 1. */
+      uint8_t c;
+
+      /* Skip any MATCH_ALL or MATCH_ONE characters that follow a
+      ** MATCH_ALL. For each MATCH_ONE, skip one character in the
+      ** test string.
+      */
+      while( (c=*zPattern) == MATCH_ALL || c == MATCH_ONE ){
+        if( c==MATCH_ONE ){
+          if( *zString==0 ) return 0;
+          SQLITE_ICU_SKIP_UTF8(zString);
+        }
+        zPattern++;
+      }
+
+      if( *zPattern==0 ) return 1;
+
+      while( *zString ){
+        if( icuLikeCompare(zPattern, zString, uEsc) ){
+          return 1;
+        }
+        SQLITE_ICU_SKIP_UTF8(zString);
+      }
+      return 0;
+
+    }else if( uPattern==MATCH_ONE && !prevEscape && uPattern!=(uint32_t)uEsc ){
+      /* Case 2. */
+      if( *zString==0 ) return 0;
+      SQLITE_ICU_SKIP_UTF8(zString);
+
+    }else if( uPattern==(uint32_t)uEsc && !prevEscape ){
+      /* Case 3. */
+      prevEscape = 1;
+
+    }else{
+      /* Case 4. */
+      uint32_t uString;
+      SQLITE_ICU_READ_UTF8(zString, uString);
+      uString = (uint32_t)u_foldCase((UChar32)uString, U_FOLD_CASE_DEFAULT);
+      uPattern = (uint32_t)u_foldCase((UChar32)uPattern, U_FOLD_CASE_DEFAULT);
+      if( uString!=uPattern ){
+        return 0;
+      }
+      prevEscape = 0;
+    }
+  }
+
+  return *zString==0;
+}
+
+/*
+** Implementation of the like() SQL function.  This function implements
+** the build-in LIKE operator.  The first argument to the function is the
+** pattern and the second argument is the string.  So, the SQL statements:
+**
+**       A LIKE B
+**
+** is implemented as like(B, A). If there is an escape character E,
+**
+**       A LIKE B ESCAPE E
+**
+** is mapped to like(B, A, E).
+*/
+static void icuLikeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zA = sqlite3_value_text(argv[0]);
+  const unsigned char *zB = sqlite3_value_text(argv[1]);
+  UChar32 uEsc = 0;
+
+  /* Limit the length of the LIKE or GLOB pattern to avoid problems
+  ** of deep recursion and N*N behavior in patternCompare().
+  */
+  if( sqlite3_value_bytes(argv[0])>SQLITE_MAX_LIKE_PATTERN_LENGTH ){
+    sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
+    return;
+  }
+
+
+  if( argc==3 ){
+    /* The escape character string must consist of a single UTF-8 character.
+    ** Otherwise, return an error.
+    */
+    int nE= sqlite3_value_bytes(argv[2]);
+    const unsigned char *zE = sqlite3_value_text(argv[2]);
+    int i = 0;
+    if( zE==0 ) return;
+    U8_NEXT(zE, i, nE, uEsc);
+    if( i!=nE){
+      sqlite3_result_error(context,
+          "ESCAPE expression must be a single character", -1);
+      return;
+    }
+  }
+
+  if( zA && zB ){
+    sqlite3_result_int(context, icuLikeCompare(zA, zB, uEsc));
+  }
+}
+
+/*
+** Function to delete compiled regexp objects. Registered as
+** a destructor function with sqlite3_set_auxdata().
+*/
+static void icuRegexpDelete(void *p){
+  URegularExpression *pExpr = (URegularExpression *)p;
+  uregex_close(pExpr);
+}
+
+/*
+** Implementation of SQLite REGEXP operator. This scalar function takes
+** two arguments. The first is a regular expression pattern to compile
+** the second is a string to match against that pattern. If either
+** argument is an SQL NULL, then NULL Is returned. Otherwise, the result
+** is 1 if the string matches the pattern, or 0 otherwise.
+**
+** SQLite maps the regexp() function to the regexp() operator such
+** that the following two are equivalent:
+**
+**     zString REGEXP zPattern
+**     regexp(zPattern, zString)
+**
+** Uses the following ICU regexp APIs:
+**
+**     uregex_open()
+**     uregex_matches()
+**     uregex_close()
+*/
+static void icuRegexpFunc(sqlite3_context *p, int nArg, sqlite3_value **apArg){
+  UErrorCode status = U_ZERO_ERROR;
+  URegularExpression *pExpr;
+  UBool res;
+  const UChar *zString = sqlite3_value_text16(apArg[1]);
+
+  (void)nArg;  /* Unused parameter */
+
+  /* If the left hand side of the regexp operator is NULL,
+  ** then the result is also NULL.
+  */
+  if( !zString ){
+    return;
+  }
+
+  pExpr = sqlite3_get_auxdata(p, 0);
+  if( !pExpr ){
+    const UChar *zPattern = sqlite3_value_text16(apArg[0]);
+    if( !zPattern ){
+      return;
+    }
+    pExpr = uregex_open(zPattern, -1, 0, 0, &status);
+
+    if( U_SUCCESS(status) ){
+      sqlite3_set_auxdata(p, 0, pExpr, icuRegexpDelete);
+      pExpr = sqlite3_get_auxdata(p, 0);
+    }
+    if( !pExpr ){
+      icuFunctionError(p, "uregex_open", status);
+      return;
+    }
+  }
+
+  /* Configure the text that the regular expression operates on. */
+  uregex_setText(pExpr, zString, -1, &status);
+  if( !U_SUCCESS(status) ){
+    icuFunctionError(p, "uregex_setText", status);
+    return;
+  }
+
+  /* Attempt the match */
+  res = uregex_matches(pExpr, 0, &status);
+  if( !U_SUCCESS(status) ){
+    icuFunctionError(p, "uregex_matches", status);
+    return;
+  }
+
+  /* Set the text that the regular expression operates on to a NULL
+  ** pointer. This is not really necessary, but it is tidier than
+  ** leaving the regular expression object configured with an invalid
+  ** pointer after this function returns.
+  */
+  uregex_setText(pExpr, 0, 0, &status);
+
+  /* Return 1 or 0. */
+  sqlite3_result_int(p, res ? 1 : 0);
+}
+
+/*
+** Implementations of scalar functions for case mapping - upper() and
+** lower(). Function upper() converts its input to upper-case (ABC).
+** Function lower() converts to lower-case (abc).
+**
+** ICU provides two types of case mapping, "general" case mapping and
+** "language specific". Refer to ICU documentation for the differences
+** between the two.
+**
+** To utilise "general" case mapping, the upper() or lower() scalar
+** functions are invoked with one argument:
+**
+**     upper('ABC') -> 'abc'
+**     lower('abc') -> 'ABC'
+**
+** To access ICU "language specific" case mapping, upper() or lower()
+** should be invoked with two arguments. The second argument is the name
+** of the locale to use. Passing an empty string ("") or SQL NULL value
+** as the second argument is the same as invoking the 1 argument version
+** of upper() or lower().
+**
+**     lower('I', 'en_us') -> 'i'
+**     lower('I', 'tr_tr') -> '\u131' (small dotless i)
+**
+** http://www.icu-project.org/userguide/posix.html#case_mappings
+*/
+static void icuCaseFunc16(sqlite3_context *p, int nArg, sqlite3_value **apArg){
+  const UChar *zInput;            /* Pointer to input string */
+  UChar *zOutput = 0;             /* Pointer to output buffer */
+  int nInput;                     /* Size of utf-16 input string in bytes */
+  int nOut;                       /* Size of output buffer in bytes */
+  int cnt;
+  int bToUpper;                   /* True for toupper(), false for tolower() */
+  UErrorCode status;
+  const char *zLocale = 0;
+
+  assert(nArg==1 || nArg==2);
+  bToUpper = (sqlite3_user_data(p)!=0);
+  if( nArg==2 ){
+    zLocale = (const char *)sqlite3_value_text(apArg[1]);
+  }
+
+  zInput = sqlite3_value_text16(apArg[0]);
+  if( !zInput ){
+    return;
+  }
+  nOut = nInput = sqlite3_value_bytes16(apArg[0]);
+  if( nOut==0 ){
+    sqlite3_result_text16(p, "", 0, SQLITE_STATIC);
+    return;
+  }
+
+  for(cnt=0; cnt<2; cnt++){
+    UChar *zNew = sqlite3_realloc(zOutput, nOut);
+    if( zNew==0 ){
+      sqlite3_free(zOutput);
+      sqlite3_result_error_nomem(p);
+      return;
+    }
+    zOutput = zNew;
+    status = U_ZERO_ERROR;
+    if( bToUpper ){
+      nOut = 2*u_strToUpper(zOutput,nOut/2,zInput,nInput/2,zLocale,&status);
+    }else{
+      nOut = 2*u_strToLower(zOutput,nOut/2,zInput,nInput/2,zLocale,&status);
+    }
+
+    if( U_SUCCESS(status) ){
+      sqlite3_result_text16(p, zOutput, nOut, xFree);
+    }else if( status==U_BUFFER_OVERFLOW_ERROR ){
+      assert( cnt==0 );
+      continue;
+    }else{
+      icuFunctionError(p, bToUpper ? "u_strToUpper" : "u_strToLower", status);
+    }
+    return;
+  }
+  assert( 0 );     /* Unreachable */
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_ICU) */
+
+/*
+** Collation sequence destructor function. The pCtx argument points to
+** a UCollator structure previously allocated using ucol_open().
+*/
+static void icuCollationDel(void *pCtx){
+  UCollator *p = (UCollator *)pCtx;
+  ucol_close(p);
+}
+
+/*
+** Collation sequence comparison function. The pCtx argument points to
+** a UCollator structure previously allocated using ucol_open().
+*/
+static int icuCollationColl(
+  void *pCtx,
+  int nLeft,
+  const void *zLeft,
+  int nRight,
+  const void *zRight
+){
+  UCollationResult res;
+  UCollator *p = (UCollator *)pCtx;
+  res = ucol_strcoll(p, (UChar *)zLeft, nLeft/2, (UChar *)zRight, nRight/2);
+  switch( res ){
+    case UCOL_LESS:    return -1;
+    case UCOL_GREATER: return +1;
+    case UCOL_EQUAL:   return 0;
+  }
+  assert(!"Unexpected return value from ucol_strcoll()");
+  return 0;
+}
+
+/*
+** Implementation of the scalar function icu_load_collation().
+**
+** This scalar function is used to add ICU collation based collation
+** types to an SQLite database connection. It is intended to be called
+** as follows:
+**
+**     SELECT icu_load_collation(<locale>, <collation-name>);
+**
+** Where <locale> is a string containing an ICU locale identifier (i.e.
+** "en_AU", "tr_TR" etc.) and <collation-name> is the name of the
+** collation sequence to create.
+*/
+static void icuLoadCollation(
+  sqlite3_context *p,
+  int nArg,
+  sqlite3_value **apArg
+){
+  sqlite3 *db = (sqlite3 *)sqlite3_user_data(p);
+  UErrorCode status = U_ZERO_ERROR;
+  const char *zLocale;      /* Locale identifier - (eg. "jp_JP") */
+  const char *zName;        /* SQL Collation sequence name (eg. "japanese") */
+  UCollator *pUCollator;    /* ICU library collation object */
+  int rc;                   /* Return code from sqlite3_create_collation_x() */
+
+  assert(nArg==2 || nArg==3);
+  (void)nArg; /* Unused parameter */
+  zLocale = (const char *)sqlite3_value_text(apArg[0]);
+  zName = (const char *)sqlite3_value_text(apArg[1]);
+
+  if( !zLocale || !zName ){
+    return;
+  }
+
+  pUCollator = ucol_open(zLocale, &status);
+  if( !U_SUCCESS(status) ){
+    icuFunctionError(p, "ucol_open", status);
+    return;
+  }
+  assert(p);
+  if(nArg==3){
+    const char *zOption = (const char*)sqlite3_value_text(apArg[2]);
+    static const struct {
+       const char *zName;
+       UColAttributeValue val;
+    } aStrength[] = {
+      {  "PRIMARY",      UCOL_PRIMARY           },
+      {  "SECONDARY",    UCOL_SECONDARY         },
+      {  "TERTIARY",     UCOL_TERTIARY          },
+      {  "DEFAULT",      UCOL_DEFAULT_STRENGTH  },
+      {  "QUARTERNARY",  UCOL_QUATERNARY        },
+      {  "IDENTICAL",    UCOL_IDENTICAL         },
+    };
+    unsigned int i;
+    for(i=0; i<sizeof(aStrength)/sizeof(aStrength[0]); i++){
+      if( sqlite3_stricmp(zOption,aStrength[i].zName)==0 ){
+        ucol_setStrength(pUCollator, aStrength[i].val);
+        break;
+      }
+    }
+    if( i>=sizeof(aStrength)/sizeof(aStrength[0]) ){
+      sqlite3_str *pStr = sqlite3_str_new(sqlite3_context_db_handle(p));
+      sqlite3_str_appendf(pStr,
+         "unknown collation strength \"%s\" - should be one of:",
+         zOption);
+      for(i=0; i<sizeof(aStrength)/sizeof(aStrength[0]); i++){
+         sqlite3_str_appendf(pStr, " %s", aStrength[i].zName);
+      }
+      sqlite3_result_error(p, sqlite3_str_value(pStr), -1);
+      sqlite3_free(sqlite3_str_finish(pStr));
+      return;
+    }
+  }
+  rc = sqlite3_create_collation_v2(db, zName, SQLITE_UTF16, (void *)pUCollator,
+      icuCollationColl, icuCollationDel
+  );
+  if( rc!=SQLITE_OK ){
+    ucol_close(pUCollator);
+    sqlite3_result_error(p, "Error registering collation function", -1);
+  }
+}
+
+/*
+** Register the ICU extension functions with database db.
+*/
+SQLITE_PRIVATE int sqlite3IcuInit(sqlite3 *db){
+# define SQLITEICU_EXTRAFLAGS (SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS)
+  static const struct IcuScalar {
+    const char *zName;                        /* Function name */
+    unsigned char nArg;                       /* Number of arguments */
+    unsigned int enc;                         /* Optimal text encoding */
+    unsigned char iContext;                   /* sqlite3_user_data() context */
+    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  } scalars[] = {
+    {"icu_load_collation",2,SQLITE_UTF8|SQLITE_DIRECTONLY,1, icuLoadCollation},
+    {"icu_load_collation",3,SQLITE_UTF8|SQLITE_DIRECTONLY,1, icuLoadCollation},
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_ICU)
+    {"regexp", 2, SQLITE_ANY|SQLITEICU_EXTRAFLAGS,         0, icuRegexpFunc},
+    {"lower",  1, SQLITE_UTF16|SQLITEICU_EXTRAFLAGS,       0, icuCaseFunc16},
+    {"lower",  2, SQLITE_UTF16|SQLITEICU_EXTRAFLAGS,       0, icuCaseFunc16},
+    {"upper",  1, SQLITE_UTF16|SQLITEICU_EXTRAFLAGS,       1, icuCaseFunc16},
+    {"upper",  2, SQLITE_UTF16|SQLITEICU_EXTRAFLAGS,       1, icuCaseFunc16},
+    {"lower",  1, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        0, icuCaseFunc16},
+    {"lower",  2, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        0, icuCaseFunc16},
+    {"upper",  1, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        1, icuCaseFunc16},
+    {"upper",  2, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        1, icuCaseFunc16},
+    {"like",   2, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        0, icuLikeFunc},
+    {"like",   3, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        0, icuLikeFunc},
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_ICU) */
+  };
+  int rc = SQLITE_OK;
+  int i;
+
+  for(i=0; rc==SQLITE_OK && i<(int)(sizeof(scalars)/sizeof(scalars[0])); i++){
+    const struct IcuScalar *p = &scalars[i];
+    rc = sqlite3_create_function(
+        db, p->zName, p->nArg, p->enc,
+        p->iContext ? (void*)db : (void*)0,
+        p->xFunc, 0, 0
+    );
+  }
+
+  return rc;
+}
+
+#ifndef SQLITE_CORE
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_icu_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi)
+  return sqlite3IcuInit(db);
+}
+#endif
+
+#endif
+
+/************** End of icu.c *************************************************/
+/************** Begin file fts3_icu.c ****************************************/
+/*
+** 2007 June 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements a tokenizer for fts3 based on the ICU library.
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+#ifdef SQLITE_ENABLE_ICU
+
+/* #include <assert.h> */
+/* #include <string.h> */
+/* #include "fts3_tokenizer.h" */
+
+#include <unicode/ubrk.h>
+/* #include <unicode/ucol.h> */
+/* #include <unicode/ustring.h> */
+#include <unicode/utf16.h>
+
+typedef struct IcuTokenizer IcuTokenizer;
+typedef struct IcuCursor IcuCursor;
+
+struct IcuTokenizer {
+  sqlite3_tokenizer base;
+  char *zLocale;
+};
+
+struct IcuCursor {
+  sqlite3_tokenizer_cursor base;
+
+  UBreakIterator *pIter;      /* ICU break-iterator object */
+  int nChar;                  /* Number of UChar elements in pInput */
+  UChar *aChar;               /* Copy of input using utf-16 encoding */
+  int *aOffset;               /* Offsets of each character in utf-8 input */
+
+  int nBuffer;
+  char *zBuffer;
+
+  int iToken;
+};
+
+/*
+** Create a new tokenizer instance.
+*/
+static int icuCreate(
+  int argc,                            /* Number of entries in argv[] */
+  const char * const *argv,            /* Tokenizer creation arguments */
+  sqlite3_tokenizer **ppTokenizer      /* OUT: Created tokenizer */
+){
+  IcuTokenizer *p;
+  int n = 0;
+
+  if( argc>0 ){
+    n = strlen(argv[0])+1;
+  }
+  p = (IcuTokenizer *)sqlite3_malloc64(sizeof(IcuTokenizer)+n);
+  if( !p ){
+    return SQLITE_NOMEM;
+  }
+  memset(p, 0, sizeof(IcuTokenizer));
+
+  if( n ){
+    p->zLocale = (char *)&p[1];
+    memcpy(p->zLocale, argv[0], n);
+  }
+
+  *ppTokenizer = (sqlite3_tokenizer *)p;
+
+  return SQLITE_OK;
+}
+
+/*
+** Destroy a tokenizer
+*/
+static int icuDestroy(sqlite3_tokenizer *pTokenizer){
+  IcuTokenizer *p = (IcuTokenizer *)pTokenizer;
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is pInput[0..nBytes-1].  A cursor
+** used to incrementally tokenize this string is returned in
+** *ppCursor.
+*/
+static int icuOpen(
+  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
+  const char *zInput,                    /* Input string */
+  int nInput,                            /* Length of zInput in bytes */
+  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
+){
+  IcuTokenizer *p = (IcuTokenizer *)pTokenizer;
+  IcuCursor *pCsr;
+
+  const int32_t opt = U_FOLD_CASE_DEFAULT;
+  UErrorCode status = U_ZERO_ERROR;
+  int nChar;
+
+  UChar32 c;
+  int iInput = 0;
+  int iOut = 0;
+
+  *ppCursor = 0;
+
+  if( zInput==0 ){
+    nInput = 0;
+    zInput = "";
+  }else if( nInput<0 ){
+    nInput = strlen(zInput);
+  }
+  nChar = nInput+1;
+  pCsr = (IcuCursor *)sqlite3_malloc64(
+      sizeof(IcuCursor) +                /* IcuCursor */
+      ((nChar+3)&~3) * sizeof(UChar) +   /* IcuCursor.aChar[] */
+      (nChar+1) * sizeof(int)            /* IcuCursor.aOffset[] */
+  );
+  if( !pCsr ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(IcuCursor));
+  pCsr->aChar = (UChar *)&pCsr[1];
+  pCsr->aOffset = (int *)&pCsr->aChar[(nChar+3)&~3];
+
+  pCsr->aOffset[iOut] = iInput;
+  U8_NEXT(zInput, iInput, nInput, c);
+  while( c>0 ){
+    int isError = 0;
+    c = u_foldCase(c, opt);
+    U16_APPEND(pCsr->aChar, iOut, nChar, c, isError);
+    if( isError ){
+      sqlite3_free(pCsr);
+      return SQLITE_ERROR;
+    }
+    pCsr->aOffset[iOut] = iInput;
+
+    if( iInput<nInput ){
+      U8_NEXT(zInput, iInput, nInput, c);
+    }else{
+      c = 0;
+    }
+  }
+
+  pCsr->pIter = ubrk_open(UBRK_WORD, p->zLocale, pCsr->aChar, iOut, &status);
+  if( !U_SUCCESS(status) ){
+    sqlite3_free(pCsr);
+    return SQLITE_ERROR;
+  }
+  pCsr->nChar = iOut;
+
+  ubrk_first(pCsr->pIter);
+  *ppCursor = (sqlite3_tokenizer_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to icuOpen().
+*/
+static int icuClose(sqlite3_tokenizer_cursor *pCursor){
+  IcuCursor *pCsr = (IcuCursor *)pCursor;
+  ubrk_close(pCsr->pIter);
+  sqlite3_free(pCsr->zBuffer);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** Extract the next token from a tokenization cursor.
+*/
+static int icuNext(
+  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by simpleOpen */
+  const char **ppToken,               /* OUT: *ppToken is the token text */
+  int *pnBytes,                       /* OUT: Number of bytes in token */
+  int *piStartOffset,                 /* OUT: Starting offset of token */
+  int *piEndOffset,                   /* OUT: Ending offset of token */
+  int *piPosition                     /* OUT: Position integer of token */
+){
+  IcuCursor *pCsr = (IcuCursor *)pCursor;
+
+  int iStart = 0;
+  int iEnd = 0;
+  int nByte = 0;
+
+  while( iStart==iEnd ){
+    UChar32 c;
+
+    iStart = ubrk_current(pCsr->pIter);
+    iEnd = ubrk_next(pCsr->pIter);
+    if( iEnd==UBRK_DONE ){
+      return SQLITE_DONE;
+    }
+
+    while( iStart<iEnd ){
+      int iWhite = iStart;
+      U16_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c);
+      if( u_isspace(c) ){
+        iStart = iWhite;
+      }else{
+        break;
+      }
+    }
+    assert(iStart<=iEnd);
+  }
+
+  do {
+    UErrorCode status = U_ZERO_ERROR;
+    if( nByte ){
+      char *zNew = sqlite3_realloc(pCsr->zBuffer, nByte);
+      if( !zNew ){
+        return SQLITE_NOMEM;
+      }
+      pCsr->zBuffer = zNew;
+      pCsr->nBuffer = nByte;
+    }
+
+    u_strToUTF8(
+        pCsr->zBuffer, pCsr->nBuffer, &nByte,    /* Output vars */
+        &pCsr->aChar[iStart], iEnd-iStart,       /* Input vars */
+        &status                                  /* Output success/failure */
+    );
+  } while( nByte>pCsr->nBuffer );
+
+  *ppToken = pCsr->zBuffer;
+  *pnBytes = nByte;
+  *piStartOffset = pCsr->aOffset[iStart];
+  *piEndOffset = pCsr->aOffset[iEnd];
+  *piPosition = pCsr->iToken++;
+
+  return SQLITE_OK;
+}
+
+/*
+** The set of routines that implement the simple tokenizer
+*/
+static const sqlite3_tokenizer_module icuTokenizerModule = {
+  0,                           /* iVersion    */
+  icuCreate,                   /* xCreate     */
+  icuDestroy,                  /* xCreate     */
+  icuOpen,                     /* xOpen       */
+  icuClose,                    /* xClose      */
+  icuNext,                     /* xNext       */
+  0,                           /* xLanguageid */
+};
+
+/*
+** Set *ppModule to point at the implementation of the ICU tokenizer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3IcuTokenizerModule(
+  sqlite3_tokenizer_module const**ppModule
+){
+  *ppModule = &icuTokenizerModule;
+}
+
+#endif /* defined(SQLITE_ENABLE_ICU) */
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_icu.c ********************************************/
+/************** Begin file sqlite3rbu.c **************************************/
+/*
+** 2014 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+**
+** OVERVIEW
+**
+**  The RBU extension requires that the RBU update be packaged as an
+**  SQLite database. The tables it expects to find are described in
+**  sqlite3rbu.h.  Essentially, for each table xyz in the target database
+**  that the user wishes to write to, a corresponding data_xyz table is
+**  created in the RBU database and populated with one row for each row to
+**  update, insert or delete from the target table.
+**
+**  The update proceeds in three stages:
+**
+**  1) The database is updated. The modified database pages are written
+**     to a *-oal file. A *-oal file is just like a *-wal file, except
+**     that it is named "<database>-oal" instead of "<database>-wal".
+**     Because regular SQLite clients do not look for file named
+**     "<database>-oal", they go on using the original database in
+**     rollback mode while the *-oal file is being generated.
+**
+**     During this stage RBU does not update the database by writing
+**     directly to the target tables. Instead it creates "imposter"
+**     tables using the SQLITE_TESTCTRL_IMPOSTER interface that it uses
+**     to update each b-tree individually. All updates required by each
+**     b-tree are completed before moving on to the next, and all
+**     updates are done in sorted key order.
+**
+**  2) The "<database>-oal" file is moved to the equivalent "<database>-wal"
+**     location using a call to rename(2). Before doing this the RBU
+**     module takes an EXCLUSIVE lock on the database file, ensuring
+**     that there are no other active readers.
+**
+**     Once the EXCLUSIVE lock is released, any other database readers
+**     detect the new *-wal file and read the database in wal mode. At
+**     this point they see the new version of the database - including
+**     the updates made as part of the RBU update.
+**
+**  3) The new *-wal file is checkpointed. This proceeds in the same way
+**     as a regular database checkpoint, except that a single frame is
+**     checkpointed each time sqlite3rbu_step() is called. If the RBU
+**     handle is closed before the entire *-wal file is checkpointed,
+**     the checkpoint progress is saved in the RBU database and the
+**     checkpoint can be resumed by another RBU client at some point in
+**     the future.
+**
+** POTENTIAL PROBLEMS
+**
+**  The rename() call might not be portable. And RBU is not currently
+**  syncing the directory after renaming the file.
+**
+**  When state is saved, any commit to the *-oal file and the commit to
+**  the RBU update database are not atomic. So if the power fails at the
+**  wrong moment they might get out of sync. As the main database will be
+**  committed before the RBU update database this will likely either just
+**  pass unnoticed, or result in SQLITE_CONSTRAINT errors (due to UNIQUE
+**  constraint violations).
+**
+**  If some client does modify the target database mid RBU update, or some
+**  other error occurs, the RBU extension will keep throwing errors. It's
+**  not really clear how to get out of this state. The system could just
+**  by delete the RBU update database and *-oal file and have the device
+**  download the update again and start over.
+**
+**  At present, for an UPDATE, both the new.* and old.* records are
+**  collected in the rbu_xyz table. And for both UPDATEs and DELETEs all
+**  fields are collected.  This means we're probably writing a lot more
+**  data to disk when saving the state of an ongoing update to the RBU
+**  update database than is strictly necessary.
+**
+*/
+
+/* #include <assert.h> */
+/* #include <string.h> */
+/* #include <stdio.h> */
+
+/* #include "sqlite3.h" */
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_RBU)
+/************** Include sqlite3rbu.h in the middle of sqlite3rbu.c ***********/
+/************** Begin file sqlite3rbu.h **************************************/
+/*
+** 2014 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the public interface for the RBU extension.
+*/
+
+/*
+** SUMMARY
+**
+** Writing a transaction containing a large number of operations on
+** b-tree indexes that are collectively larger than the available cache
+** memory can be very inefficient.
+**
+** The problem is that in order to update a b-tree, the leaf page (at least)
+** containing the entry being inserted or deleted must be modified. If the
+** working set of leaves is larger than the available cache memory, then a
+** single leaf that is modified more than once as part of the transaction
+** may be loaded from or written to the persistent media multiple times.
+** Additionally, because the index updates are likely to be applied in
+** random order, access to pages within the database is also likely to be in
+** random order, which is itself quite inefficient.
+**
+** One way to improve the situation is to sort the operations on each index
+** by index key before applying them to the b-tree. This leads to an IO
+** pattern that resembles a single linear scan through the index b-tree,
+** and all but guarantees each modified leaf page is loaded and stored
+** exactly once. SQLite uses this trick to improve the performance of
+** CREATE INDEX commands. This extension allows it to be used to improve
+** the performance of large transactions on existing databases.
+**
+** Additionally, this extension allows the work involved in writing the
+** large transaction to be broken down into sub-transactions performed
+** sequentially by separate processes. This is useful if the system cannot
+** guarantee that a single update process will run for long enough to apply
+** the entire update, for example because the update is being applied on a
+** mobile device that is frequently rebooted. Even after the writer process
+** has committed one or more sub-transactions, other database clients continue
+** to read from the original database snapshot. In other words, partially
+** applied transactions are not visible to other clients.
+**
+** "RBU" stands for "Resumable Bulk Update". As in a large database update
+** transmitted via a wireless network to a mobile device. A transaction
+** applied using this extension is hence refered to as an "RBU update".
+**
+**
+** LIMITATIONS
+**
+** An "RBU update" transaction is subject to the following limitations:
+**
+**   * The transaction must consist of INSERT, UPDATE and DELETE operations
+**     only.
+**
+**   * INSERT statements may not use any default values.
+**
+**   * UPDATE and DELETE statements must identify their target rows by
+**     non-NULL PRIMARY KEY values. Rows with NULL values stored in PRIMARY
+**     KEY fields may not be updated or deleted. If the table being written
+**     has no PRIMARY KEY, affected rows must be identified by rowid.
+**
+**   * UPDATE statements may not modify PRIMARY KEY columns.
+**
+**   * No triggers will be fired.
+**
+**   * No foreign key violations are detected or reported.
+**
+**   * CHECK constraints are not enforced.
+**
+**   * No constraint handling mode except for "OR ROLLBACK" is supported.
+**
+**
+** PREPARATION
+**
+** An "RBU update" is stored as a separate SQLite database. A database
+** containing an RBU update is an "RBU database". For each table in the
+** target database to be updated, the RBU database should contain a table
+** named "data_<target name>" containing the same set of columns as the
+** target table, and one more - "rbu_control". The data_% table should
+** have no PRIMARY KEY or UNIQUE constraints, but each column should have
+** the same type as the corresponding column in the target database.
+** The "rbu_control" column should have no type at all. For example, if
+** the target database contains:
+**
+**   CREATE TABLE t1(a INTEGER PRIMARY KEY, b TEXT, c UNIQUE);
+**
+** Then the RBU database should contain:
+**
+**   CREATE TABLE data_t1(a INTEGER, b TEXT, c, rbu_control);
+**
+** The order of the columns in the data_% table does not matter.
+**
+** Instead of a regular table, the RBU database may also contain virtual
+** tables or views named using the data_<target> naming scheme.
+**
+** Instead of the plain data_<target> naming scheme, RBU database tables
+** may also be named data<integer>_<target>, where <integer> is any sequence
+** of zero or more numeric characters (0-9). This can be significant because
+** tables within the RBU database are always processed in order sorted by
+** name. By judicious selection of the <integer> portion of the names
+** of the RBU tables the user can therefore control the order in which they
+** are processed. This can be useful, for example, to ensure that "external
+** content" FTS4 tables are updated before their underlying content tables.
+**
+** If the target database table is a virtual table or a table that has no
+** PRIMARY KEY declaration, the data_% table must also contain a column
+** named "rbu_rowid". This column is mapped to the table's implicit primary
+** key column - "rowid". Virtual tables for which the "rowid" column does
+** not function like a primary key value cannot be updated using RBU. For
+** example, if the target db contains either of the following:
+**
+**   CREATE VIRTUAL TABLE x1 USING fts3(a, b);
+**   CREATE TABLE x1(a, b)
+**
+** then the RBU database should contain:
+**
+**   CREATE TABLE data_x1(a, b, rbu_rowid, rbu_control);
+**
+** All non-hidden columns (i.e. all columns matched by "SELECT *") of the
+** target table must be present in the input table. For virtual tables,
+** hidden columns are optional - they are updated by RBU if present in
+** the input table, or not otherwise. For example, to write to an fts4
+** table with a hidden languageid column such as:
+**
+**   CREATE VIRTUAL TABLE ft1 USING fts4(a, b, languageid='langid');
+**
+** Either of the following input table schemas may be used:
+**
+**   CREATE TABLE data_ft1(a, b, langid, rbu_rowid, rbu_control);
+**   CREATE TABLE data_ft1(a, b, rbu_rowid, rbu_control);
+**
+** For each row to INSERT into the target database as part of the RBU
+** update, the corresponding data_% table should contain a single record
+** with the "rbu_control" column set to contain integer value 0. The
+** other columns should be set to the values that make up the new record
+** to insert.
+**
+** If the target database table has an INTEGER PRIMARY KEY, it is not
+** possible to insert a NULL value into the IPK column. Attempting to
+** do so results in an SQLITE_MISMATCH error.
+**
+** For each row to DELETE from the target database as part of the RBU
+** update, the corresponding data_% table should contain a single record
+** with the "rbu_control" column set to contain integer value 1. The
+** real primary key values of the row to delete should be stored in the
+** corresponding columns of the data_% table. The values stored in the
+** other columns are not used.
+**
+** For each row to UPDATE from the target database as part of the RBU
+** update, the corresponding data_% table should contain a single record
+** with the "rbu_control" column set to contain a value of type text.
+** The real primary key values identifying the row to update should be
+** stored in the corresponding columns of the data_% table row, as should
+** the new values of all columns being update. The text value in the
+** "rbu_control" column must contain the same number of characters as
+** there are columns in the target database table, and must consist entirely
+** of 'x' and '.' characters (or in some special cases 'd' - see below). For
+** each column that is being updated, the corresponding character is set to
+** 'x'. For those that remain as they are, the corresponding character of the
+** rbu_control value should be set to '.'. For example, given the tables
+** above, the update statement:
+**
+**   UPDATE t1 SET c = 'usa' WHERE a = 4;
+**
+** is represented by the data_t1 row created by:
+**
+**   INSERT INTO data_t1(a, b, c, rbu_control) VALUES(4, NULL, 'usa', '..x');
+**
+** Instead of an 'x' character, characters of the rbu_control value specified
+** for UPDATEs may also be set to 'd'. In this case, instead of updating the
+** target table with the value stored in the corresponding data_% column, the
+** user-defined SQL function "rbu_delta()" is invoked and the result stored in
+** the target table column. rbu_delta() is invoked with two arguments - the
+** original value currently stored in the target table column and the
+** value specified in the data_xxx table.
+**
+** For example, this row:
+**
+**   INSERT INTO data_t1(a, b, c, rbu_control) VALUES(4, NULL, 'usa', '..d');
+**
+** is similar to an UPDATE statement such as:
+**
+**   UPDATE t1 SET c = rbu_delta(c, 'usa') WHERE a = 4;
+**
+** Finally, if an 'f' character appears in place of a 'd' or 's' in an
+** ota_control string, the contents of the data_xxx table column is assumed
+** to be a "fossil delta" - a patch to be applied to a blob value in the
+** format used by the fossil source-code management system. In this case
+** the existing value within the target database table must be of type BLOB.
+** It is replaced by the result of applying the specified fossil delta to
+** itself.
+**
+** If the target database table is a virtual table or a table with no PRIMARY
+** KEY, the rbu_control value should not include a character corresponding
+** to the rbu_rowid value. For example, this:
+**
+**   INSERT INTO data_ft1(a, b, rbu_rowid, rbu_control)
+**       VALUES(NULL, 'usa', 12, '.x');
+**
+** causes a result similar to:
+**
+**   UPDATE ft1 SET b = 'usa' WHERE rowid = 12;
+**
+** The data_xxx tables themselves should have no PRIMARY KEY declarations.
+** However, RBU is more efficient if reading the rows in from each data_xxx
+** table in "rowid" order is roughly the same as reading them sorted by
+** the PRIMARY KEY of the corresponding target database table. In other
+** words, rows should be sorted using the destination table PRIMARY KEY
+** fields before they are inserted into the data_xxx tables.
+**
+** USAGE
+**
+** The API declared below allows an application to apply an RBU update
+** stored on disk to an existing target database. Essentially, the
+** application:
+**
+**     1) Opens an RBU handle using the sqlite3rbu_open() function.
+**
+**     2) Registers any required virtual table modules with the database
+**        handle returned by sqlite3rbu_db(). Also, if required, register
+**        the rbu_delta() implementation.
+**
+**     3) Calls the sqlite3rbu_step() function one or more times on
+**        the new handle. Each call to sqlite3rbu_step() performs a single
+**        b-tree operation, so thousands of calls may be required to apply
+**        a complete update.
+**
+**     4) Calls sqlite3rbu_close() to close the RBU update handle. If
+**        sqlite3rbu_step() has been called enough times to completely
+**        apply the update to the target database, then the RBU database
+**        is marked as fully applied. Otherwise, the state of the RBU
+**        update application is saved in the RBU database for later
+**        resumption.
+**
+** See comments below for more detail on APIs.
+**
+** If an update is only partially applied to the target database by the
+** time sqlite3rbu_close() is called, various state information is saved
+** within the RBU database. This allows subsequent processes to automatically
+** resume the RBU update from where it left off.
+**
+** To remove all RBU extension state information, returning an RBU database
+** to its original contents, it is sufficient to drop all tables that begin
+** with the prefix "rbu_"
+**
+** DATABASE LOCKING
+**
+** An RBU update may not be applied to a database in WAL mode. Attempting
+** to do so is an error (SQLITE_ERROR).
+**
+** While an RBU handle is open, a SHARED lock may be held on the target
+** database file. This means it is possible for other clients to read the
+** database, but not to write it.
+**
+** If an RBU update is started and then suspended before it is completed,
+** then an external client writes to the database, then attempting to resume
+** the suspended RBU update is also an error (SQLITE_BUSY).
+*/
+
+#ifndef _SQLITE3RBU_H
+#define _SQLITE3RBU_H
+
+/* #include "sqlite3.h"              ** Required for error code definitions ** */
+
+#if 0
+extern "C" {
+#endif
+
+typedef struct sqlite3rbu sqlite3rbu;
+
+/*
+** Open an RBU handle.
+**
+** Argument zTarget is the path to the target database. Argument zRbu is
+** the path to the RBU database. Each call to this function must be matched
+** by a call to sqlite3rbu_close(). When opening the databases, RBU passes
+** the SQLITE_CONFIG_URI flag to sqlite3_open_v2(). So if either zTarget
+** or zRbu begin with "file:", it will be interpreted as an SQLite
+** database URI, not a regular file name.
+**
+** If the zState argument is passed a NULL value, the RBU extension stores
+** the current state of the update (how many rows have been updated, which
+** indexes are yet to be updated etc.) within the RBU database itself. This
+** can be convenient, as it means that the RBU application does not need to
+** organize removing a separate state file after the update is concluded.
+** Or, if zState is non-NULL, it must be a path to a database file in which
+** the RBU extension can store the state of the update.
+**
+** When resuming an RBU update, the zState argument must be passed the same
+** value as when the RBU update was started.
+**
+** Once the RBU update is finished, the RBU extension does not
+** automatically remove any zState database file, even if it created it.
+**
+** By default, RBU uses the default VFS to access the files on disk. To
+** use a VFS other than the default, an SQLite "file:" URI containing a
+** "vfs=..." option may be passed as the zTarget option.
+**
+** IMPORTANT NOTE FOR ZIPVFS USERS: The RBU extension works with all of
+** SQLite's built-in VFSs, including the multiplexor VFS. However it does
+** not work out of the box with zipvfs. Refer to the comment describing
+** the zipvfs_create_vfs() API below for details on using RBU with zipvfs.
+*/
+SQLITE_API sqlite3rbu *sqlite3rbu_open(
+  const char *zTarget,
+  const char *zRbu,
+  const char *zState
+);
+
+/*
+** Open an RBU handle to perform an RBU vacuum on database file zTarget.
+** An RBU vacuum is similar to SQLite's built-in VACUUM command, except
+** that it can be suspended and resumed like an RBU update.
+**
+** The second argument to this function identifies a database in which
+** to store the state of the RBU vacuum operation if it is suspended. The
+** first time sqlite3rbu_vacuum() is called, to start an RBU vacuum
+** operation, the state database should either not exist or be empty
+** (contain no tables). If an RBU vacuum is suspended by calling
+** sqlite3rbu_close() on the RBU handle before sqlite3rbu_step() has
+** returned SQLITE_DONE, the vacuum state is stored in the state database.
+** The vacuum can be resumed by calling this function to open a new RBU
+** handle specifying the same target and state databases.
+**
+** If the second argument passed to this function is NULL, then the
+** name of the state database is "<database>-vacuum", where <database>
+** is the name of the target database file. In this case, on UNIX, if the
+** state database is not already present in the file-system, it is created
+** with the same permissions as the target db is made.
+**
+** With an RBU vacuum, it is an SQLITE_MISUSE error if the name of the
+** state database ends with "-vactmp". This name is reserved for internal
+** use.
+**
+** This function does not delete the state database after an RBU vacuum
+** is completed, even if it created it. However, if the call to
+** sqlite3rbu_close() returns any value other than SQLITE_OK, the contents
+** of the state tables within the state database are zeroed. This way,
+** the next call to sqlite3rbu_vacuum() opens a handle that starts a
+** new RBU vacuum operation.
+**
+** As with sqlite3rbu_open(), Zipvfs users should rever to the comment
+** describing the sqlite3rbu_create_vfs() API function below for
+** a description of the complications associated with using RBU with
+** zipvfs databases.
+*/
+SQLITE_API sqlite3rbu *sqlite3rbu_vacuum(
+  const char *zTarget,
+  const char *zState
+);
+
+/*
+** Configure a limit for the amount of temp space that may be used by
+** the RBU handle passed as the first argument. The new limit is specified
+** in bytes by the second parameter. If it is positive, the limit is updated.
+** If the second parameter to this function is passed zero, then the limit
+** is removed entirely. If the second parameter is negative, the limit is
+** not modified (this is useful for querying the current limit).
+**
+** In all cases the returned value is the current limit in bytes (zero
+** indicates unlimited).
+**
+** If the temp space limit is exceeded during operation, an SQLITE_FULL
+** error is returned.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_temp_size_limit(sqlite3rbu*, sqlite3_int64);
+
+/*
+** Return the current amount of temp file space, in bytes, currently used by
+** the RBU handle passed as the only argument.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_temp_size(sqlite3rbu*);
+
+/*
+** Internally, each RBU connection uses a separate SQLite database
+** connection to access the target and rbu update databases. This
+** API allows the application direct access to these database handles.
+**
+** The first argument passed to this function must be a valid, open, RBU
+** handle. The second argument should be passed zero to access the target
+** database handle, or non-zero to access the rbu update database handle.
+** Accessing the underlying database handles may be useful in the
+** following scenarios:
+**
+**   * If any target tables are virtual tables, it may be necessary to
+**     call sqlite3_create_module() on the target database handle to
+**     register the required virtual table implementations.
+**
+**   * If the data_xxx tables in the RBU source database are virtual
+**     tables, the application may need to call sqlite3_create_module() on
+**     the rbu update db handle to any required virtual table
+**     implementations.
+**
+**   * If the application uses the "rbu_delta()" feature described above,
+**     it must use sqlite3_create_function() or similar to register the
+**     rbu_delta() implementation with the target database handle.
+**
+** If an error has occurred, either while opening or stepping the RBU object,
+** this function may return NULL. The error code and message may be collected
+** when sqlite3rbu_close() is called.
+**
+** Database handles returned by this function remain valid until the next
+** call to any sqlite3rbu_xxx() function other than sqlite3rbu_db().
+*/
+SQLITE_API sqlite3 *sqlite3rbu_db(sqlite3rbu*, int bRbu);
+
+/*
+** Do some work towards applying the RBU update to the target db.
+**
+** Return SQLITE_DONE if the update has been completely applied, or
+** SQLITE_OK if no error occurs but there remains work to do to apply
+** the RBU update. If an error does occur, some other error code is
+** returned.
+**
+** Once a call to sqlite3rbu_step() has returned a value other than
+** SQLITE_OK, all subsequent calls on the same RBU handle are no-ops
+** that immediately return the same value.
+*/
+SQLITE_API int sqlite3rbu_step(sqlite3rbu *pRbu);
+
+/*
+** Force RBU to save its state to disk.
+**
+** If a power failure or application crash occurs during an update, following
+** system recovery RBU may resume the update from the point at which the state
+** was last saved. In other words, from the most recent successful call to
+** sqlite3rbu_close() or this function.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+SQLITE_API int sqlite3rbu_savestate(sqlite3rbu *pRbu);
+
+/*
+** Close an RBU handle.
+**
+** If the RBU update has been completely applied, mark the RBU database
+** as fully applied. Otherwise, assuming no error has occurred, save the
+** current state of the RBU update appliation to the RBU database.
+**
+** If an error has already occurred as part of an sqlite3rbu_step()
+** or sqlite3rbu_open() call, or if one occurs within this function, an
+** SQLite error code is returned. Additionally, if pzErrmsg is not NULL,
+** *pzErrmsg may be set to point to a buffer containing a utf-8 formatted
+** English language error message. It is the responsibility of the caller to
+** eventually free any such buffer using sqlite3_free().
+**
+** Otherwise, if no error occurs, this function returns SQLITE_OK if the
+** update has been partially applied, or SQLITE_DONE if it has been
+** completely applied.
+*/
+SQLITE_API int sqlite3rbu_close(sqlite3rbu *pRbu, char **pzErrmsg);
+
+/*
+** Return the total number of key-value operations (inserts, deletes or
+** updates) that have been performed on the target database since the
+** current RBU update was started.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_progress(sqlite3rbu *pRbu);
+
+/*
+** Obtain permyriadage (permyriadage is to 10000 as percentage is to 100)
+** progress indications for the two stages of an RBU update. This API may
+** be useful for driving GUI progress indicators and similar.
+**
+** An RBU update is divided into two stages:
+**
+**   * Stage 1, in which changes are accumulated in an oal/wal file, and
+**   * Stage 2, in which the contents of the wal file are copied into the
+**     main database.
+**
+** The update is visible to non-RBU clients during stage 2. During stage 1
+** non-RBU reader clients may see the original database.
+**
+** If this API is called during stage 2 of the update, output variable
+** (*pnOne) is set to 10000 to indicate that stage 1 has finished and (*pnTwo)
+** to a value between 0 and 10000 to indicate the permyriadage progress of
+** stage 2. A value of 5000 indicates that stage 2 is half finished,
+** 9000 indicates that it is 90% finished, and so on.
+**
+** If this API is called during stage 1 of the update, output variable
+** (*pnTwo) is set to 0 to indicate that stage 2 has not yet started. The
+** value to which (*pnOne) is set depends on whether or not the RBU
+** database contains an "rbu_count" table. The rbu_count table, if it
+** exists, must contain the same columns as the following:
+**
+**   CREATE TABLE rbu_count(tbl TEXT PRIMARY KEY, cnt INTEGER) WITHOUT ROWID;
+**
+** There must be one row in the table for each source (data_xxx) table within
+** the RBU database. The 'tbl' column should contain the name of the source
+** table. The 'cnt' column should contain the number of rows within the
+** source table.
+**
+** If the rbu_count table is present and populated correctly and this
+** API is called during stage 1, the *pnOne output variable is set to the
+** permyriadage progress of the same stage. If the rbu_count table does
+** not exist, then (*pnOne) is set to -1 during stage 1. If the rbu_count
+** table exists but is not correctly populated, the value of the *pnOne
+** output variable during stage 1 is undefined.
+*/
+SQLITE_API void sqlite3rbu_bp_progress(sqlite3rbu *pRbu, int *pnOne, int*pnTwo);
+
+/*
+** Obtain an indication as to the current stage of an RBU update or vacuum.
+** This function always returns one of the SQLITE_RBU_STATE_XXX constants
+** defined in this file. Return values should be interpreted as follows:
+**
+** SQLITE_RBU_STATE_OAL:
+**   RBU is currently building a *-oal file. The next call to sqlite3rbu_step()
+**   may either add further data to the *-oal file, or compute data that will
+**   be added by a subsequent call.
+**
+** SQLITE_RBU_STATE_MOVE:
+**   RBU has finished building the *-oal file. The next call to sqlite3rbu_step()
+**   will move the *-oal file to the equivalent *-wal path. If the current
+**   operation is an RBU update, then the updated version of the database
+**   file will become visible to ordinary SQLite clients following the next
+**   call to sqlite3rbu_step().
+**
+** SQLITE_RBU_STATE_CHECKPOINT:
+**   RBU is currently performing an incremental checkpoint. The next call to
+**   sqlite3rbu_step() will copy a page of data from the *-wal file into
+**   the target database file.
+**
+** SQLITE_RBU_STATE_DONE:
+**   The RBU operation has finished. Any subsequent calls to sqlite3rbu_step()
+**   will immediately return SQLITE_DONE.
+**
+** SQLITE_RBU_STATE_ERROR:
+**   An error has occurred. Any subsequent calls to sqlite3rbu_step() will
+**   immediately return the SQLite error code associated with the error.
+*/
+#define SQLITE_RBU_STATE_OAL        1
+#define SQLITE_RBU_STATE_MOVE       2
+#define SQLITE_RBU_STATE_CHECKPOINT 3
+#define SQLITE_RBU_STATE_DONE       4
+#define SQLITE_RBU_STATE_ERROR      5
+
+SQLITE_API int sqlite3rbu_state(sqlite3rbu *pRbu);
+
+/*
+** As part of applying an RBU update or performing an RBU vacuum operation,
+** the system must at one point move the *-oal file to the equivalent *-wal
+** path. Normally, it does this by invoking POSIX function rename(2) directly.
+** Except on WINCE platforms, where it uses win32 API MoveFileW(). This
+** function may be used to register a callback that the RBU module will invoke
+** instead of one of these APIs.
+**
+** If a callback is registered with an RBU handle, it invokes it instead
+** of rename(2) when it needs to move a file within the file-system. The
+** first argument passed to the xRename() callback is a copy of the second
+** argument (pArg) passed to this function. The second is the full path
+** to the file to move and the third the full path to which it should be
+** moved. The callback function should return SQLITE_OK to indicate
+** success. If an error occurs, it should return an SQLite error code.
+** In this case the RBU operation will be abandoned and the error returned
+** to the RBU user.
+**
+** Passing a NULL pointer in place of the xRename argument to this function
+** restores the default behaviour.
+*/
+SQLITE_API void sqlite3rbu_rename_handler(
+  sqlite3rbu *pRbu,
+  void *pArg,
+  int (*xRename)(void *pArg, const char *zOld, const char *zNew)
+);
+
+
+/*
+** Create an RBU VFS named zName that accesses the underlying file-system
+** via existing VFS zParent. Or, if the zParent parameter is passed NULL,
+** then the new RBU VFS uses the default system VFS to access the file-system.
+** The new object is registered as a non-default VFS with SQLite before
+** returning.
+**
+** Part of the RBU implementation uses a custom VFS object. Usually, this
+** object is created and deleted automatically by RBU.
+**
+** The exception is for applications that also use zipvfs. In this case,
+** the custom VFS must be explicitly created by the user before the RBU
+** handle is opened. The RBU VFS should be installed so that the zipvfs
+** VFS uses the RBU VFS, which in turn uses any other VFS layers in use
+** (for example multiplexor) to access the file-system. For example,
+** to assemble an RBU enabled VFS stack that uses both zipvfs and
+** multiplexor (error checking omitted):
+**
+**     // Create a VFS named "multiplex" (not the default).
+**     sqlite3_multiplex_initialize(0, 0);
+**
+**     // Create an rbu VFS named "rbu" that uses multiplexor. If the
+**     // second argument were replaced with NULL, the "rbu" VFS would
+**     // access the file-system via the system default VFS, bypassing the
+**     // multiplexor.
+**     sqlite3rbu_create_vfs("rbu", "multiplex");
+**
+**     // Create a zipvfs VFS named "zipvfs" that uses rbu.
+**     zipvfs_create_vfs_v3("zipvfs", "rbu", 0, xCompressorAlgorithmDetector);
+**
+**     // Make zipvfs the default VFS.
+**     sqlite3_vfs_register(sqlite3_vfs_find("zipvfs"), 1);
+**
+** Because the default VFS created above includes a RBU functionality, it
+** may be used by RBU clients. Attempting to use RBU with a zipvfs VFS stack
+** that does not include the RBU layer results in an error.
+**
+** The overhead of adding the "rbu" VFS to the system is negligible for
+** non-RBU users. There is no harm in an application accessing the
+** file-system via "rbu" all the time, even if it only uses RBU functionality
+** occasionally.
+*/
+SQLITE_API int sqlite3rbu_create_vfs(const char *zName, const char *zParent);
+
+/*
+** Deregister and destroy an RBU vfs created by an earlier call to
+** sqlite3rbu_create_vfs().
+**
+** VFS objects are not reference counted. If a VFS object is destroyed
+** before all database handles that use it have been closed, the results
+** are undefined.
+*/
+SQLITE_API void sqlite3rbu_destroy_vfs(const char *zName);
+
+#if 0
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* _SQLITE3RBU_H */
+
+/************** End of sqlite3rbu.h ******************************************/
+/************** Continuing where we left off in sqlite3rbu.c *****************/
+
+#if defined(_WIN32_WCE)
+/* #include "windows.h" */
+#endif
+
+/* Maximum number of prepared UPDATE statements held by this module */
+#define SQLITE_RBU_UPDATE_CACHESIZE 16
+
+/* Delta checksums disabled by default.  Compile with -DRBU_ENABLE_DELTA_CKSUM
+** to enable checksum verification.
+*/
+#ifndef RBU_ENABLE_DELTA_CKSUM
+# define RBU_ENABLE_DELTA_CKSUM 0
+#endif
+
+/*
+** Swap two objects of type TYPE.
+*/
+#if !defined(SQLITE_AMALGAMATION)
+# define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
+#endif
+
+/*
+** Name of the URI option that causes RBU to take an exclusive lock as
+** part of the incremental checkpoint operation.
+*/
+#define RBU_EXCLUSIVE_CHECKPOINT "rbu_exclusive_checkpoint"
+
+
+/*
+** The rbu_state table is used to save the state of a partially applied
+** update so that it can be resumed later. The table consists of integer
+** keys mapped to values as follows:
+**
+** RBU_STATE_STAGE:
+**   May be set to integer values 1, 2, 4 or 5. As follows:
+**       1: the *-rbu file is currently under construction.
+**       2: the *-rbu file has been constructed, but not yet moved
+**          to the *-wal path.
+**       4: the checkpoint is underway.
+**       5: the rbu update has been checkpointed.
+**
+** RBU_STATE_TBL:
+**   Only valid if STAGE==1. The target database name of the table
+**   currently being written.
+**
+** RBU_STATE_IDX:
+**   Only valid if STAGE==1. The target database name of the index
+**   currently being written, or NULL if the main table is currently being
+**   updated.
+**
+** RBU_STATE_ROW:
+**   Only valid if STAGE==1. Number of rows already processed for the current
+**   table/index.
+**
+** RBU_STATE_PROGRESS:
+**   Trbul number of sqlite3rbu_step() calls made so far as part of this
+**   rbu update.
+**
+** RBU_STATE_CKPT:
+**   Valid if STAGE==4. The 64-bit checksum associated with the wal-index
+**   header created by recovering the *-wal file. This is used to detect
+**   cases when another client appends frames to the *-wal file in the
+**   middle of an incremental checkpoint (an incremental checkpoint cannot
+**   be continued if this happens).
+**
+** RBU_STATE_COOKIE:
+**   Valid if STAGE==1. The current change-counter cookie value in the
+**   target db file.
+**
+** RBU_STATE_OALSZ:
+**   Valid if STAGE==1. The size in bytes of the *-oal file.
+**
+** RBU_STATE_DATATBL:
+**   Only valid if STAGE==1. The RBU database name of the table
+**   currently being read.
+*/
+#define RBU_STATE_STAGE        1
+#define RBU_STATE_TBL          2
+#define RBU_STATE_IDX          3
+#define RBU_STATE_ROW          4
+#define RBU_STATE_PROGRESS     5
+#define RBU_STATE_CKPT         6
+#define RBU_STATE_COOKIE       7
+#define RBU_STATE_OALSZ        8
+#define RBU_STATE_PHASEONESTEP 9
+#define RBU_STATE_DATATBL     10
+
+#define RBU_STAGE_OAL         1
+#define RBU_STAGE_MOVE        2
+#define RBU_STAGE_CAPTURE     3
+#define RBU_STAGE_CKPT        4
+#define RBU_STAGE_DONE        5
+
+
+#define RBU_CREATE_STATE \
+  "CREATE TABLE IF NOT EXISTS %s.rbu_state(k INTEGER PRIMARY KEY, v)"
+
+typedef struct RbuFrame RbuFrame;
+typedef struct RbuObjIter RbuObjIter;
+typedef struct RbuState RbuState;
+typedef struct RbuSpan RbuSpan;
+typedef struct rbu_vfs rbu_vfs;
+typedef struct rbu_file rbu_file;
+typedef struct RbuUpdateStmt RbuUpdateStmt;
+
+#if !defined(SQLITE_AMALGAMATION)
+typedef unsigned int u32;
+typedef unsigned short u16;
+typedef unsigned char u8;
+typedef sqlite3_int64 i64;
+typedef sqlite3_uint64 u64;
+#endif
+
+/*
+** These values must match the values defined in wal.c for the equivalent
+** locks. These are not magic numbers as they are part of the SQLite file
+** format.
+*/
+#define WAL_LOCK_WRITE  0
+#define WAL_LOCK_CKPT   1
+#define WAL_LOCK_READ0  3
+
+#define SQLITE_FCNTL_RBUCNT    5149216
+
+/*
+** A structure to store values read from the rbu_state table in memory.
+*/
+struct RbuState {
+  int eStage;
+  char *zTbl;
+  char *zDataTbl;
+  char *zIdx;
+  i64 iWalCksum;
+  int nRow;
+  i64 nProgress;
+  u32 iCookie;
+  i64 iOalSz;
+  i64 nPhaseOneStep;
+};
+
+struct RbuUpdateStmt {
+  char *zMask;                    /* Copy of update mask used with pUpdate */
+  sqlite3_stmt *pUpdate;          /* Last update statement (or NULL) */
+  RbuUpdateStmt *pNext;
+};
+
+struct RbuSpan {
+  const char *zSpan;
+  int nSpan;
+};
+
+/*
+** An iterator of this type is used to iterate through all objects in
+** the target database that require updating. For each such table, the
+** iterator visits, in order:
+**
+**     * the table itself,
+**     * each index of the table (zero or more points to visit), and
+**     * a special "cleanup table" state.
+**
+** abIndexed:
+**   If the table has no indexes on it, abIndexed is set to NULL. Otherwise,
+**   it points to an array of flags nTblCol elements in size. The flag is
+**   set for each column that is either a part of the PK or a part of an
+**   index. Or clear otherwise.
+**
+**   If there are one or more partial indexes on the table, all fields of
+**   this array set set to 1. This is because in that case, the module has
+**   no way to tell which fields will be required to add and remove entries
+**   from the partial indexes.
+**
+*/
+struct RbuObjIter {
+  sqlite3_stmt *pTblIter;         /* Iterate through tables */
+  sqlite3_stmt *pIdxIter;         /* Index iterator */
+  int nTblCol;                    /* Size of azTblCol[] array */
+  char **azTblCol;                /* Array of unquoted target column names */
+  char **azTblType;               /* Array of target column types */
+  int *aiSrcOrder;                /* src table col -> target table col */
+  u8 *abTblPk;                    /* Array of flags, set on target PK columns */
+  u8 *abNotNull;                  /* Array of flags, set on NOT NULL columns */
+  u8 *abIndexed;                  /* Array of flags, set on indexed & PK cols */
+  int eType;                      /* Table type - an RBU_PK_XXX value */
+
+  /* Output variables. zTbl==0 implies EOF. */
+  int bCleanup;                   /* True in "cleanup" state */
+  const char *zTbl;               /* Name of target db table */
+  const char *zDataTbl;           /* Name of rbu db table (or null) */
+  const char *zIdx;               /* Name of target db index (or null) */
+  int iTnum;                      /* Root page of current object */
+  int iPkTnum;                    /* If eType==EXTERNAL, root of PK index */
+  int bUnique;                    /* Current index is unique */
+  int nIndex;                     /* Number of aux. indexes on table zTbl */
+
+  /* Statements created by rbuObjIterPrepareAll() */
+  int nCol;                       /* Number of columns in current object */
+  sqlite3_stmt *pSelect;          /* Source data */
+  sqlite3_stmt *pInsert;          /* Statement for INSERT operations */
+  sqlite3_stmt *pDelete;          /* Statement for DELETE ops */
+  sqlite3_stmt *pTmpInsert;       /* Insert into rbu_tmp_$zDataTbl */
+  int nIdxCol;
+  RbuSpan *aIdxCol;
+  char *zIdxSql;
+
+  /* Last UPDATE used (for PK b-tree updates only), or NULL. */
+  RbuUpdateStmt *pRbuUpdate;
+};
+
+/*
+** Values for RbuObjIter.eType
+**
+**     0: Table does not exist (error)
+**     1: Table has an implicit rowid.
+**     2: Table has an explicit IPK column.
+**     3: Table has an external PK index.
+**     4: Table is WITHOUT ROWID.
+**     5: Table is a virtual table.
+*/
+#define RBU_PK_NOTABLE        0
+#define RBU_PK_NONE           1
+#define RBU_PK_IPK            2
+#define RBU_PK_EXTERNAL       3
+#define RBU_PK_WITHOUT_ROWID  4
+#define RBU_PK_VTAB           5
+
+
+/*
+** Within the RBU_STAGE_OAL stage, each call to sqlite3rbu_step() performs
+** one of the following operations.
+*/
+#define RBU_INSERT     1          /* Insert on a main table b-tree */
+#define RBU_DELETE     2          /* Delete a row from a main table b-tree */
+#define RBU_REPLACE    3          /* Delete and then insert a row */
+#define RBU_IDX_DELETE 4          /* Delete a row from an aux. index b-tree */
+#define RBU_IDX_INSERT 5          /* Insert on an aux. index b-tree */
+
+#define RBU_UPDATE     6          /* Update a row in a main table b-tree */
+
+/*
+** A single step of an incremental checkpoint - frame iWalFrame of the wal
+** file should be copied to page iDbPage of the database file.
+*/
+struct RbuFrame {
+  u32 iDbPage;
+  u32 iWalFrame;
+};
+
+#ifndef UNUSED_PARAMETER
+/*
+** The following macros are used to suppress compiler warnings and to
+** make it clear to human readers when a function parameter is deliberately
+** left unused within the body of a function. This usually happens when
+** a function is called via a function pointer. For example the
+** implementation of an SQL aggregate step callback may not use the
+** parameter indicating the number of arguments passed to the aggregate,
+** if it knows that this is enforced elsewhere.
+**
+** When a function parameter is not used at all within the body of a function,
+** it is generally named "NotUsed" or "NotUsed2" to make things even clearer.
+** However, these macros may also be used to suppress warnings related to
+** parameters that may or may not be used depending on compilation options.
+** For example those parameters only used in assert() statements. In these
+** cases the parameters are named as per the usual conventions.
+*/
+#define UNUSED_PARAMETER(x) (void)(x)
+#define UNUSED_PARAMETER2(x,y) UNUSED_PARAMETER(x),UNUSED_PARAMETER(y)
+#endif
+
+/*
+** RBU handle.
+**
+** nPhaseOneStep:
+**   If the RBU database contains an rbu_count table, this value is set to
+**   a running estimate of the number of b-tree operations required to
+**   finish populating the *-oal file. This allows the sqlite3_bp_progress()
+**   API to calculate the permyriadage progress of populating the *-oal file
+**   using the formula:
+**
+**     permyriadage = (10000 * nProgress) / nPhaseOneStep
+**
+**   nPhaseOneStep is initialized to the sum of:
+**
+**     nRow * (nIndex + 1)
+**
+**   for all source tables in the RBU database, where nRow is the number
+**   of rows in the source table and nIndex the number of indexes on the
+**   corresponding target database table.
+**
+**   This estimate is accurate if the RBU update consists entirely of
+**   INSERT operations. However, it is inaccurate if:
+**
+**     * the RBU update contains any UPDATE operations. If the PK specified
+**       for an UPDATE operation does not exist in the target table, then
+**       no b-tree operations are required on index b-trees. Or if the
+**       specified PK does exist, then (nIndex*2) such operations are
+**       required (one delete and one insert on each index b-tree).
+**
+**     * the RBU update contains any DELETE operations for which the specified
+**       PK does not exist. In this case no operations are required on index
+**       b-trees.
+**
+**     * the RBU update contains REPLACE operations. These are similar to
+**       UPDATE operations.
+**
+**   nPhaseOneStep is updated to account for the conditions above during the
+**   first pass of each source table. The updated nPhaseOneStep value is
+**   stored in the rbu_state table if the RBU update is suspended.
+*/
+struct sqlite3rbu {
+  int eStage;                     /* Value of RBU_STATE_STAGE field */
+  sqlite3 *dbMain;                /* target database handle */
+  sqlite3 *dbRbu;                 /* rbu database handle */
+  char *zTarget;                  /* Path to target db */
+  char *zRbu;                     /* Path to rbu db */
+  char *zState;                   /* Path to state db (or NULL if zRbu) */
+  char zStateDb[5];               /* Db name for state ("stat" or "main") */
+  int rc;                         /* Value returned by last rbu_step() call */
+  char *zErrmsg;                  /* Error message if rc!=SQLITE_OK */
+  int nStep;                      /* Rows processed for current object */
+  sqlite3_int64 nProgress;        /* Rows processed for all objects */
+  RbuObjIter objiter;             /* Iterator for skipping through tbl/idx */
+  const char *zVfsName;           /* Name of automatically created rbu vfs */
+  rbu_file *pTargetFd;            /* File handle open on target db */
+  int nPagePerSector;             /* Pages per sector for pTargetFd */
+  i64 iOalSz;
+  i64 nPhaseOneStep;
+  void *pRenameArg;
+  int (*xRename)(void*, const char*, const char*);
+
+  /* The following state variables are used as part of the incremental
+  ** checkpoint stage (eStage==RBU_STAGE_CKPT). See comments surrounding
+  ** function rbuSetupCheckpoint() for details.  */
+  u32 iMaxFrame;                  /* Largest iWalFrame value in aFrame[] */
+  u32 mLock;
+  int nFrame;                     /* Entries in aFrame[] array */
+  int nFrameAlloc;                /* Allocated size of aFrame[] array */
+  RbuFrame *aFrame;
+  int pgsz;
+  u8 *aBuf;
+  i64 iWalCksum;
+  i64 szTemp;                     /* Current size of all temp files in use */
+  i64 szTempLimit;                /* Total size limit for temp files */
+
+  /* Used in RBU vacuum mode only */
+  int nRbu;                       /* Number of RBU VFS in the stack */
+  rbu_file *pRbuFd;               /* Fd for main db of dbRbu */
+};
+
+/*
+** An rbu VFS is implemented using an instance of this structure.
+**
+** Variable pRbu is only non-NULL for automatically created RBU VFS objects.
+** It is NULL for RBU VFS objects created explicitly using
+** sqlite3rbu_create_vfs(). It is used to track the total amount of temp
+** space used by the RBU handle.
+*/
+struct rbu_vfs {
+  sqlite3_vfs base;               /* rbu VFS shim methods */
+  sqlite3_vfs *pRealVfs;          /* Underlying VFS */
+  sqlite3_mutex *mutex;           /* Mutex to protect pMain */
+  sqlite3rbu *pRbu;               /* Owner RBU object */
+  rbu_file *pMain;                /* List of main db files */
+  rbu_file *pMainRbu;             /* List of main db files with pRbu!=0 */
+};
+
+/*
+** Each file opened by an rbu VFS is represented by an instance of
+** the following structure.
+**
+** If this is a temporary file (pRbu!=0 && flags&DELETE_ON_CLOSE), variable
+** "sz" is set to the current size of the database file.
+*/
+struct rbu_file {
+  sqlite3_file base;              /* sqlite3_file methods */
+  sqlite3_file *pReal;            /* Underlying file handle */
+  rbu_vfs *pRbuVfs;               /* Pointer to the rbu_vfs object */
+  sqlite3rbu *pRbu;               /* Pointer to rbu object (rbu target only) */
+  i64 sz;                         /* Size of file in bytes (temp only) */
+
+  int openFlags;                  /* Flags this file was opened with */
+  u32 iCookie;                    /* Cookie value for main db files */
+  u8 iWriteVer;                   /* "write-version" value for main db files */
+  u8 bNolock;                     /* True to fail EXCLUSIVE locks */
+
+  int nShm;                       /* Number of entries in apShm[] array */
+  char **apShm;                   /* Array of mmap'd *-shm regions */
+  char *zDel;                     /* Delete this when closing file */
+
+  const char *zWal;               /* Wal filename for this main db file */
+  rbu_file *pWalFd;               /* Wal file descriptor for this main db */
+  rbu_file *pMainNext;            /* Next MAIN_DB file */
+  rbu_file *pMainRbuNext;         /* Next MAIN_DB file with pRbu!=0 */
+};
+
+/*
+** True for an RBU vacuum handle, or false otherwise.
+*/
+#define rbuIsVacuum(p) ((p)->zTarget==0)
+
+
+/*************************************************************************
+** The following three functions, found below:
+**
+**   rbuDeltaGetInt()
+**   rbuDeltaChecksum()
+**   rbuDeltaApply()
+**
+** are lifted from the fossil source code (http://fossil-scm.org). They
+** are used to implement the scalar SQL function rbu_fossil_delta().
+*/
+
+/*
+** Read bytes from *pz and convert them into a positive integer.  When
+** finished, leave *pz pointing to the first character past the end of
+** the integer.  The *pLen parameter holds the length of the string
+** in *pz and is decremented once for each character in the integer.
+*/
+static unsigned int rbuDeltaGetInt(const char **pz, int *pLen){
+  static const signed char zValue[] = {
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+     0,  1,  2,  3,  4,  5,  6,  7,    8,  9, -1, -1, -1, -1, -1, -1,
+    -1, 10, 11, 12, 13, 14, 15, 16,   17, 18, 19, 20, 21, 22, 23, 24,
+    25, 26, 27, 28, 29, 30, 31, 32,   33, 34, 35, -1, -1, -1, -1, 36,
+    -1, 37, 38, 39, 40, 41, 42, 43,   44, 45, 46, 47, 48, 49, 50, 51,
+    52, 53, 54, 55, 56, 57, 58, 59,   60, 61, 62, -1, -1, -1, 63, -1,
+  };
+  unsigned int v = 0;
+  int c;
+  unsigned char *z = (unsigned char*)*pz;
+  unsigned char *zStart = z;
+  while( (c = zValue[0x7f&*(z++)])>=0 ){
+     v = (v<<6) + c;
+  }
+  z--;
+  *pLen -= (int)(z - zStart);
+  *pz = (char*)z;
+  return v;
+}
+
+#if RBU_ENABLE_DELTA_CKSUM
+/*
+** Compute a 32-bit checksum on the N-byte buffer.  Return the result.
+*/
+static unsigned int rbuDeltaChecksum(const char *zIn, size_t N){
+  const unsigned char *z = (const unsigned char *)zIn;
+  unsigned sum0 = 0;
+  unsigned sum1 = 0;
+  unsigned sum2 = 0;
+  unsigned sum3 = 0;
+  while(N >= 16){
+    sum0 += ((unsigned)z[0] + z[4] + z[8] + z[12]);
+    sum1 += ((unsigned)z[1] + z[5] + z[9] + z[13]);
+    sum2 += ((unsigned)z[2] + z[6] + z[10]+ z[14]);
+    sum3 += ((unsigned)z[3] + z[7] + z[11]+ z[15]);
+    z += 16;
+    N -= 16;
+  }
+  while(N >= 4){
+    sum0 += z[0];
+    sum1 += z[1];
+    sum2 += z[2];
+    sum3 += z[3];
+    z += 4;
+    N -= 4;
+  }
+  sum3 += (sum2 << 8) + (sum1 << 16) + (sum0 << 24);
+  switch(N){
+    case 3:   sum3 += (z[2] << 8);
+    case 2:   sum3 += (z[1] << 16);
+    case 1:   sum3 += (z[0] << 24);
+    default:  ;
+  }
+  return sum3;
+}
+#endif
+
+/*
+** Apply a delta.
+**
+** The output buffer should be big enough to hold the whole output
+** file and a NUL terminator at the end.  The delta_output_size()
+** routine will determine this size for you.
+**
+** The delta string should be null-terminated.  But the delta string
+** may contain embedded NUL characters (if the input and output are
+** binary files) so we also have to pass in the length of the delta in
+** the lenDelta parameter.
+**
+** This function returns the size of the output file in bytes (excluding
+** the final NUL terminator character).  Except, if the delta string is
+** malformed or intended for use with a source file other than zSrc,
+** then this routine returns -1.
+**
+** Refer to the delta_create() documentation above for a description
+** of the delta file format.
+*/
+static int rbuDeltaApply(
+  const char *zSrc,      /* The source or pattern file */
+  int lenSrc,            /* Length of the source file */
+  const char *zDelta,    /* Delta to apply to the pattern */
+  int lenDelta,          /* Length of the delta */
+  char *zOut             /* Write the output into this preallocated buffer */
+){
+  unsigned int limit;
+  unsigned int total = 0;
+#if RBU_ENABLE_DELTA_CKSUM
+  char *zOrigOut = zOut;
+#endif
+
+  limit = rbuDeltaGetInt(&zDelta, &lenDelta);
+  if( *zDelta!='\n' ){
+    /* ERROR: size integer not terminated by "\n" */
+    return -1;
+  }
+  zDelta++; lenDelta--;
+  while( *zDelta && lenDelta>0 ){
+    unsigned int cnt, ofst;
+    cnt = rbuDeltaGetInt(&zDelta, &lenDelta);
+    switch( zDelta[0] ){
+      case '@': {
+        zDelta++; lenDelta--;
+        ofst = rbuDeltaGetInt(&zDelta, &lenDelta);
+        if( lenDelta>0 && zDelta[0]!=',' ){
+          /* ERROR: copy command not terminated by ',' */
+          return -1;
+        }
+        zDelta++; lenDelta--;
+        total += cnt;
+        if( total>limit ){
+          /* ERROR: copy exceeds output file size */
+          return -1;
+        }
+        if( (int)(ofst+cnt) > lenSrc ){
+          /* ERROR: copy extends past end of input */
+          return -1;
+        }
+        memcpy(zOut, &zSrc[ofst], cnt);
+        zOut += cnt;
+        break;
+      }
+      case ':': {
+        zDelta++; lenDelta--;
+        total += cnt;
+        if( total>limit ){
+          /* ERROR:  insert command gives an output larger than predicted */
+          return -1;
+        }
+        if( (int)cnt>lenDelta ){
+          /* ERROR: insert count exceeds size of delta */
+          return -1;
+        }
+        memcpy(zOut, zDelta, cnt);
+        zOut += cnt;
+        zDelta += cnt;
+        lenDelta -= cnt;
+        break;
+      }
+      case ';': {
+        zDelta++; lenDelta--;
+        zOut[0] = 0;
+#if RBU_ENABLE_DELTA_CKSUM
+        if( cnt!=rbuDeltaChecksum(zOrigOut, total) ){
+          /* ERROR:  bad checksum */
+          return -1;
+        }
+#endif
+        if( total!=limit ){
+          /* ERROR: generated size does not match predicted size */
+          return -1;
+        }
+        return total;
+      }
+      default: {
+        /* ERROR: unknown delta operator */
+        return -1;
+      }
+    }
+  }
+  /* ERROR: unterminated delta */
+  return -1;
+}
+
+static int rbuDeltaOutputSize(const char *zDelta, int lenDelta){
+  int size;
+  size = rbuDeltaGetInt(&zDelta, &lenDelta);
+  if( *zDelta!='\n' ){
+    /* ERROR: size integer not terminated by "\n" */
+    return -1;
+  }
+  return size;
+}
+
+/*
+** End of code taken from fossil.
+*************************************************************************/
+
+/*
+** Implementation of SQL scalar function rbu_fossil_delta().
+**
+** This function applies a fossil delta patch to a blob. Exactly two
+** arguments must be passed to this function. The first is the blob to
+** patch and the second the patch to apply. If no error occurs, this
+** function returns the patched blob.
+*/
+static void rbuFossilDeltaFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *aDelta;
+  int nDelta;
+  const char *aOrig;
+  int nOrig;
+
+  int nOut;
+  int nOut2;
+  char *aOut;
+
+  assert( argc==2 );
+  UNUSED_PARAMETER(argc);
+
+  nOrig = sqlite3_value_bytes(argv[0]);
+  aOrig = (const char*)sqlite3_value_blob(argv[0]);
+  nDelta = sqlite3_value_bytes(argv[1]);
+  aDelta = (const char*)sqlite3_value_blob(argv[1]);
+
+  /* Figure out the size of the output */
+  nOut = rbuDeltaOutputSize(aDelta, nDelta);
+  if( nOut<0 ){
+    sqlite3_result_error(context, "corrupt fossil delta", -1);
+    return;
+  }
+
+  aOut = sqlite3_malloc(nOut+1);
+  if( aOut==0 ){
+    sqlite3_result_error_nomem(context);
+  }else{
+    nOut2 = rbuDeltaApply(aOrig, nOrig, aDelta, nDelta, aOut);
+    if( nOut2!=nOut ){
+      sqlite3_free(aOut);
+      sqlite3_result_error(context, "corrupt fossil delta", -1);
+    }else{
+      sqlite3_result_blob(context, aOut, nOut, sqlite3_free);
+    }
+  }
+}
+
+
+/*
+** Prepare the SQL statement in buffer zSql against database handle db.
+** If successful, set *ppStmt to point to the new statement and return
+** SQLITE_OK.
+**
+** Otherwise, if an error does occur, set *ppStmt to NULL and return
+** an SQLite error code. Additionally, set output variable *pzErrmsg to
+** point to a buffer containing an error message. It is the responsibility
+** of the caller to (eventually) free this buffer using sqlite3_free().
+*/
+static int prepareAndCollectError(
+  sqlite3 *db,
+  sqlite3_stmt **ppStmt,
+  char **pzErrmsg,
+  const char *zSql
+){
+  int rc = sqlite3_prepare_v2(db, zSql, -1, ppStmt, 0);
+  if( rc!=SQLITE_OK ){
+    *pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    *ppStmt = 0;
+  }
+  return rc;
+}
+
+/*
+** Reset the SQL statement passed as the first argument. Return a copy
+** of the value returned by sqlite3_reset().
+**
+** If an error has occurred, then set *pzErrmsg to point to a buffer
+** containing an error message. It is the responsibility of the caller
+** to eventually free this buffer using sqlite3_free().
+*/
+static int resetAndCollectError(sqlite3_stmt *pStmt, char **pzErrmsg){
+  int rc = sqlite3_reset(pStmt);
+  if( rc!=SQLITE_OK ){
+    *pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(sqlite3_db_handle(pStmt)));
+  }
+  return rc;
+}
+
+/*
+** Unless it is NULL, argument zSql points to a buffer allocated using
+** sqlite3_malloc containing an SQL statement. This function prepares the SQL
+** statement against database db and frees the buffer. If statement
+** compilation is successful, *ppStmt is set to point to the new statement
+** handle and SQLITE_OK is returned.
+**
+** Otherwise, if an error occurs, *ppStmt is set to NULL and an error code
+** returned. In this case, *pzErrmsg may also be set to point to an error
+** message. It is the responsibility of the caller to free this error message
+** buffer using sqlite3_free().
+**
+** If argument zSql is NULL, this function assumes that an OOM has occurred.
+** In this case SQLITE_NOMEM is returned and *ppStmt set to NULL.
+*/
+static int prepareFreeAndCollectError(
+  sqlite3 *db,
+  sqlite3_stmt **ppStmt,
+  char **pzErrmsg,
+  char *zSql
+){
+  int rc;
+  assert( *pzErrmsg==0 );
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+    *ppStmt = 0;
+  }else{
+    rc = prepareAndCollectError(db, ppStmt, pzErrmsg, zSql);
+    sqlite3_free(zSql);
+  }
+  return rc;
+}
+
+/*
+** Free the RbuObjIter.azTblCol[] and RbuObjIter.abTblPk[] arrays allocated
+** by an earlier call to rbuObjIterCacheTableInfo().
+*/
+static void rbuObjIterFreeCols(RbuObjIter *pIter){
+  int i;
+  for(i=0; i<pIter->nTblCol; i++){
+    sqlite3_free(pIter->azTblCol[i]);
+    sqlite3_free(pIter->azTblType[i]);
+  }
+  sqlite3_free(pIter->azTblCol);
+  pIter->azTblCol = 0;
+  pIter->azTblType = 0;
+  pIter->aiSrcOrder = 0;
+  pIter->abTblPk = 0;
+  pIter->abNotNull = 0;
+  pIter->nTblCol = 0;
+  pIter->eType = 0;               /* Invalid value */
+}
+
+/*
+** Finalize all statements and free all allocations that are specific to
+** the current object (table/index pair).
+*/
+static void rbuObjIterClearStatements(RbuObjIter *pIter){
+  RbuUpdateStmt *pUp;
+
+  sqlite3_finalize(pIter->pSelect);
+  sqlite3_finalize(pIter->pInsert);
+  sqlite3_finalize(pIter->pDelete);
+  sqlite3_finalize(pIter->pTmpInsert);
+  pUp = pIter->pRbuUpdate;
+  while( pUp ){
+    RbuUpdateStmt *pTmp = pUp->pNext;
+    sqlite3_finalize(pUp->pUpdate);
+    sqlite3_free(pUp);
+    pUp = pTmp;
+  }
+  sqlite3_free(pIter->aIdxCol);
+  sqlite3_free(pIter->zIdxSql);
+
+  pIter->pSelect = 0;
+  pIter->pInsert = 0;
+  pIter->pDelete = 0;
+  pIter->pRbuUpdate = 0;
+  pIter->pTmpInsert = 0;
+  pIter->nCol = 0;
+  pIter->nIdxCol = 0;
+  pIter->aIdxCol = 0;
+  pIter->zIdxSql = 0;
+}
+
+/*
+** Clean up any resources allocated as part of the iterator object passed
+** as the only argument.
+*/
+static void rbuObjIterFinalize(RbuObjIter *pIter){
+  rbuObjIterClearStatements(pIter);
+  sqlite3_finalize(pIter->pTblIter);
+  sqlite3_finalize(pIter->pIdxIter);
+  rbuObjIterFreeCols(pIter);
+  memset(pIter, 0, sizeof(RbuObjIter));
+}
+
+/*
+** Advance the iterator to the next position.
+**
+** If no error occurs, SQLITE_OK is returned and the iterator is left
+** pointing to the next entry. Otherwise, an error code and message is
+** left in the RBU handle passed as the first argument. A copy of the
+** error code is returned.
+*/
+static int rbuObjIterNext(sqlite3rbu *p, RbuObjIter *pIter){
+  int rc = p->rc;
+  if( rc==SQLITE_OK ){
+
+    /* Free any SQLite statements used while processing the previous object */
+    rbuObjIterClearStatements(pIter);
+    if( pIter->zIdx==0 ){
+      rc = sqlite3_exec(p->dbMain,
+          "DROP TRIGGER IF EXISTS temp.rbu_insert_tr;"
+          "DROP TRIGGER IF EXISTS temp.rbu_update1_tr;"
+          "DROP TRIGGER IF EXISTS temp.rbu_update2_tr;"
+          "DROP TRIGGER IF EXISTS temp.rbu_delete_tr;"
+          , 0, 0, &p->zErrmsg
+      );
+    }
+
+    if( rc==SQLITE_OK ){
+      if( pIter->bCleanup ){
+        rbuObjIterFreeCols(pIter);
+        pIter->bCleanup = 0;
+        rc = sqlite3_step(pIter->pTblIter);
+        if( rc!=SQLITE_ROW ){
+          rc = resetAndCollectError(pIter->pTblIter, &p->zErrmsg);
+          pIter->zTbl = 0;
+          pIter->zDataTbl = 0;
+        }else{
+          pIter->zTbl = (const char*)sqlite3_column_text(pIter->pTblIter, 0);
+          pIter->zDataTbl = (const char*)sqlite3_column_text(pIter->pTblIter,1);
+          rc = (pIter->zDataTbl && pIter->zTbl) ? SQLITE_OK : SQLITE_NOMEM;
+        }
+      }else{
+        if( pIter->zIdx==0 ){
+          sqlite3_stmt *pIdx = pIter->pIdxIter;
+          rc = sqlite3_bind_text(pIdx, 1, pIter->zTbl, -1, SQLITE_STATIC);
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3_step(pIter->pIdxIter);
+          if( rc!=SQLITE_ROW ){
+            rc = resetAndCollectError(pIter->pIdxIter, &p->zErrmsg);
+            pIter->bCleanup = 1;
+            pIter->zIdx = 0;
+          }else{
+            pIter->zIdx = (const char*)sqlite3_column_text(pIter->pIdxIter, 0);
+            pIter->iTnum = sqlite3_column_int(pIter->pIdxIter, 1);
+            pIter->bUnique = sqlite3_column_int(pIter->pIdxIter, 2);
+            rc = pIter->zIdx ? SQLITE_OK : SQLITE_NOMEM;
+          }
+        }
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    rbuObjIterFinalize(pIter);
+    p->rc = rc;
+  }
+  return rc;
+}
+
+
+/*
+** The implementation of the rbu_target_name() SQL function. This function
+** accepts one or two arguments. The first argument is the name of a table -
+** the name of a table in the RBU database.  The second, if it is present, is 1
+** for a view or 0 for a table.
+**
+** For a non-vacuum RBU handle, if the table name matches the pattern:
+**
+**     data[0-9]_<name>
+**
+** where <name> is any sequence of 1 or more characters, <name> is returned.
+** Otherwise, if the only argument does not match the above pattern, an SQL
+** NULL is returned.
+**
+**     "data_t1"     -> "t1"
+**     "data0123_t2" -> "t2"
+**     "dataAB_t3"   -> NULL
+**
+** For an rbu vacuum handle, a copy of the first argument is returned if
+** the second argument is either missing or 0 (not a view).
+*/
+static void rbuTargetNameFunc(
+  sqlite3_context *pCtx,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3rbu *p = sqlite3_user_data(pCtx);
+  const char *zIn;
+  assert( argc==1 || argc==2 );
+
+  zIn = (const char*)sqlite3_value_text(argv[0]);
+  if( zIn ){
+    if( rbuIsVacuum(p) ){
+      assert( argc==2 || argc==1 );
+      if( argc==1 || 0==sqlite3_value_int(argv[1]) ){
+        sqlite3_result_text(pCtx, zIn, -1, SQLITE_STATIC);
+      }
+    }else{
+      if( strlen(zIn)>4 && memcmp("data", zIn, 4)==0 ){
+        int i;
+        for(i=4; zIn[i]>='0' && zIn[i]<='9'; i++);
+        if( zIn[i]=='_' && zIn[i+1] ){
+          sqlite3_result_text(pCtx, &zIn[i+1], -1, SQLITE_STATIC);
+        }
+      }
+    }
+  }
+}
+
+/*
+** Initialize the iterator structure passed as the second argument.
+**
+** If no error occurs, SQLITE_OK is returned and the iterator is left
+** pointing to the first entry. Otherwise, an error code and message is
+** left in the RBU handle passed as the first argument. A copy of the
+** error code is returned.
+*/
+static int rbuObjIterFirst(sqlite3rbu *p, RbuObjIter *pIter){
+  int rc;
+  memset(pIter, 0, sizeof(RbuObjIter));
+
+  rc = prepareFreeAndCollectError(p->dbRbu, &pIter->pTblIter, &p->zErrmsg,
+    sqlite3_mprintf(
+      "SELECT rbu_target_name(name, type='view') AS target, name "
+      "FROM sqlite_schema "
+      "WHERE type IN ('table', 'view') AND target IS NOT NULL "
+      " %s "
+      "ORDER BY name"
+  , rbuIsVacuum(p) ? "AND rootpage!=0 AND rootpage IS NOT NULL" : ""));
+
+  if( rc==SQLITE_OK ){
+    rc = prepareAndCollectError(p->dbMain, &pIter->pIdxIter, &p->zErrmsg,
+        "SELECT name, rootpage, sql IS NULL OR substr(8, 6)=='UNIQUE' "
+        "  FROM main.sqlite_schema "
+        "  WHERE type='index' AND tbl_name = ?"
+    );
+  }
+
+  pIter->bCleanup = 1;
+  p->rc = rc;
+  return rbuObjIterNext(p, pIter);
+}
+
+/*
+** This is a wrapper around "sqlite3_mprintf(zFmt, ...)". If an OOM occurs,
+** an error code is stored in the RBU handle passed as the first argument.
+**
+** If an error has already occurred (p->rc is already set to something other
+** than SQLITE_OK), then this function returns NULL without modifying the
+** stored error code. In this case it still calls sqlite3_free() on any
+** printf() parameters associated with %z conversions.
+*/
+static char *rbuMPrintf(sqlite3rbu *p, const char *zFmt, ...){
+  char *zSql = 0;
+  va_list ap;
+  va_start(ap, zFmt);
+  zSql = sqlite3_vmprintf(zFmt, ap);
+  if( p->rc==SQLITE_OK ){
+    if( zSql==0 ) p->rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_free(zSql);
+    zSql = 0;
+  }
+  va_end(ap);
+  return zSql;
+}
+
+/*
+** Argument zFmt is a sqlite3_mprintf() style format string. The trailing
+** arguments are the usual subsitution values. This function performs
+** the printf() style substitutions and executes the result as an SQL
+** statement on the RBU handles database.
+**
+** If an error occurs, an error code and error message is stored in the
+** RBU handle. If an error has already occurred when this function is
+** called, it is a no-op.
+*/
+static int rbuMPrintfExec(sqlite3rbu *p, sqlite3 *db, const char *zFmt, ...){
+  va_list ap;
+  char *zSql;
+  va_start(ap, zFmt);
+  zSql = sqlite3_vmprintf(zFmt, ap);
+  if( p->rc==SQLITE_OK ){
+    if( zSql==0 ){
+      p->rc = SQLITE_NOMEM;
+    }else{
+      p->rc = sqlite3_exec(db, zSql, 0, 0, &p->zErrmsg);
+    }
+  }
+  sqlite3_free(zSql);
+  va_end(ap);
+  return p->rc;
+}
+
+/*
+** Attempt to allocate and return a pointer to a zeroed block of nByte
+** bytes.
+**
+** If an error (i.e. an OOM condition) occurs, return NULL and leave an
+** error code in the rbu handle passed as the first argument. Or, if an
+** error has already occurred when this function is called, return NULL
+** immediately without attempting the allocation or modifying the stored
+** error code.
+*/
+static void *rbuMalloc(sqlite3rbu *p, sqlite3_int64 nByte){
+  void *pRet = 0;
+  if( p->rc==SQLITE_OK ){
+    assert( nByte>0 );
+    pRet = sqlite3_malloc64(nByte);
+    if( pRet==0 ){
+      p->rc = SQLITE_NOMEM;
+    }else{
+      memset(pRet, 0, nByte);
+    }
+  }
+  return pRet;
+}
+
+
+/*
+** Allocate and zero the pIter->azTblCol[] and abTblPk[] arrays so that
+** there is room for at least nCol elements. If an OOM occurs, store an
+** error code in the RBU handle passed as the first argument.
+*/
+static void rbuAllocateIterArrays(sqlite3rbu *p, RbuObjIter *pIter, int nCol){
+  sqlite3_int64 nByte = (2*sizeof(char*) + sizeof(int) + 3*sizeof(u8)) * nCol;
+  char **azNew;
+
+  azNew = (char**)rbuMalloc(p, nByte);
+  if( azNew ){
+    pIter->azTblCol = azNew;
+    pIter->azTblType = &azNew[nCol];
+    pIter->aiSrcOrder = (int*)&pIter->azTblType[nCol];
+    pIter->abTblPk = (u8*)&pIter->aiSrcOrder[nCol];
+    pIter->abNotNull = (u8*)&pIter->abTblPk[nCol];
+    pIter->abIndexed = (u8*)&pIter->abNotNull[nCol];
+  }
+}
+
+/*
+** The first argument must be a nul-terminated string. This function
+** returns a copy of the string in memory obtained from sqlite3_malloc().
+** It is the responsibility of the caller to eventually free this memory
+** using sqlite3_free().
+**
+** If an OOM condition is encountered when attempting to allocate memory,
+** output variable (*pRc) is set to SQLITE_NOMEM before returning. Otherwise,
+** if the allocation succeeds, (*pRc) is left unchanged.
+*/
+static char *rbuStrndup(const char *zStr, int *pRc){
+  char *zRet = 0;
+
+  if( *pRc==SQLITE_OK ){
+    if( zStr ){
+      size_t nCopy = strlen(zStr) + 1;
+      zRet = (char*)sqlite3_malloc64(nCopy);
+      if( zRet ){
+        memcpy(zRet, zStr, nCopy);
+      }else{
+        *pRc = SQLITE_NOMEM;
+      }
+    }
+  }
+
+  return zRet;
+}
+
+/*
+** Finalize the statement passed as the second argument.
+**
+** If the sqlite3_finalize() call indicates that an error occurs, and the
+** rbu handle error code is not already set, set the error code and error
+** message accordingly.
+*/
+static void rbuFinalize(sqlite3rbu *p, sqlite3_stmt *pStmt){
+  sqlite3 *db = sqlite3_db_handle(pStmt);
+  int rc = sqlite3_finalize(pStmt);
+  if( p->rc==SQLITE_OK && rc!=SQLITE_OK ){
+    p->rc = rc;
+    p->zErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+  }
+}
+
+/* Determine the type of a table.
+**
+**   peType is of type (int*), a pointer to an output parameter of type
+**   (int). This call sets the output parameter as follows, depending
+**   on the type of the table specified by parameters dbName and zTbl.
+**
+**     RBU_PK_NOTABLE:       No such table.
+**     RBU_PK_NONE:          Table has an implicit rowid.
+**     RBU_PK_IPK:           Table has an explicit IPK column.
+**     RBU_PK_EXTERNAL:      Table has an external PK index.
+**     RBU_PK_WITHOUT_ROWID: Table is WITHOUT ROWID.
+**     RBU_PK_VTAB:          Table is a virtual table.
+**
+**   Argument *piPk is also of type (int*), and also points to an output
+**   parameter. Unless the table has an external primary key index
+**   (i.e. unless *peType is set to 3), then *piPk is set to zero. Or,
+**   if the table does have an external primary key index, then *piPk
+**   is set to the root page number of the primary key index before
+**   returning.
+**
+** ALGORITHM:
+**
+**   if( no entry exists in sqlite_schema ){
+**     return RBU_PK_NOTABLE
+**   }else if( sql for the entry starts with "CREATE VIRTUAL" ){
+**     return RBU_PK_VTAB
+**   }else if( "PRAGMA index_list()" for the table contains a "pk" index ){
+**     if( the index that is the pk exists in sqlite_schema ){
+**       *piPK = rootpage of that index.
+**       return RBU_PK_EXTERNAL
+**     }else{
+**       return RBU_PK_WITHOUT_ROWID
+**     }
+**   }else if( "PRAGMA table_info()" lists one or more "pk" columns ){
+**     return RBU_PK_IPK
+**   }else{
+**     return RBU_PK_NONE
+**   }
+*/
+static void rbuTableType(
+  sqlite3rbu *p,
+  const char *zTab,
+  int *peType,
+  int *piTnum,
+  int *piPk
+){
+  /*
+  ** 0) SELECT count(*) FROM sqlite_schema where name=%Q AND IsVirtual(%Q)
+  ** 1) PRAGMA index_list = ?
+  ** 2) SELECT count(*) FROM sqlite_schema where name=%Q
+  ** 3) PRAGMA table_info = ?
+  */
+  sqlite3_stmt *aStmt[4] = {0, 0, 0, 0};
+
+  *peType = RBU_PK_NOTABLE;
+  *piPk = 0;
+
+  assert( p->rc==SQLITE_OK );
+  p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[0], &p->zErrmsg,
+    sqlite3_mprintf(
+          "SELECT "
+          " (sql COLLATE nocase BETWEEN 'CREATE VIRTUAL' AND 'CREATE VIRTUAM'),"
+          " rootpage"
+          "  FROM sqlite_schema"
+          " WHERE name=%Q", zTab
+  ));
+  if( p->rc!=SQLITE_OK || sqlite3_step(aStmt[0])!=SQLITE_ROW ){
+    /* Either an error, or no such table. */
+    goto rbuTableType_end;
+  }
+  if( sqlite3_column_int(aStmt[0], 0) ){
+    *peType = RBU_PK_VTAB;                     /* virtual table */
+    goto rbuTableType_end;
+  }
+  *piTnum = sqlite3_column_int(aStmt[0], 1);
+
+  p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[1], &p->zErrmsg,
+    sqlite3_mprintf("PRAGMA index_list=%Q",zTab)
+  );
+  if( p->rc ) goto rbuTableType_end;
+  while( sqlite3_step(aStmt[1])==SQLITE_ROW ){
+    const u8 *zOrig = sqlite3_column_text(aStmt[1], 3);
+    const u8 *zIdx = sqlite3_column_text(aStmt[1], 1);
+    if( zOrig && zIdx && zOrig[0]=='p' ){
+      p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[2], &p->zErrmsg,
+          sqlite3_mprintf(
+            "SELECT rootpage FROM sqlite_schema WHERE name = %Q", zIdx
+      ));
+      if( p->rc==SQLITE_OK ){
+        if( sqlite3_step(aStmt[2])==SQLITE_ROW ){
+          *piPk = sqlite3_column_int(aStmt[2], 0);
+          *peType = RBU_PK_EXTERNAL;
+        }else{
+          *peType = RBU_PK_WITHOUT_ROWID;
+        }
+      }
+      goto rbuTableType_end;
+    }
+  }
+
+  p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[3], &p->zErrmsg,
+    sqlite3_mprintf("PRAGMA table_info=%Q",zTab)
+  );
+  if( p->rc==SQLITE_OK ){
+    while( sqlite3_step(aStmt[3])==SQLITE_ROW ){
+      if( sqlite3_column_int(aStmt[3],5)>0 ){
+        *peType = RBU_PK_IPK;                /* explicit IPK column */
+        goto rbuTableType_end;
+      }
+    }
+    *peType = RBU_PK_NONE;
+  }
+
+rbuTableType_end: {
+    unsigned int i;
+    for(i=0; i<sizeof(aStmt)/sizeof(aStmt[0]); i++){
+      rbuFinalize(p, aStmt[i]);
+    }
+  }
+}
+
+/*
+** This is a helper function for rbuObjIterCacheTableInfo(). It populates
+** the pIter->abIndexed[] array.
+*/
+static void rbuObjIterCacheIndexedCols(sqlite3rbu *p, RbuObjIter *pIter){
+  sqlite3_stmt *pList = 0;
+  int bIndex = 0;
+
+  if( p->rc==SQLITE_OK ){
+    memcpy(pIter->abIndexed, pIter->abTblPk, sizeof(u8)*pIter->nTblCol);
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pList, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.index_list = %Q", pIter->zTbl)
+    );
+  }
+
+  pIter->nIndex = 0;
+  while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pList) ){
+    const char *zIdx = (const char*)sqlite3_column_text(pList, 1);
+    int bPartial = sqlite3_column_int(pList, 4);
+    sqlite3_stmt *pXInfo = 0;
+    if( zIdx==0 ) break;
+    if( bPartial ){
+      memset(pIter->abIndexed, 0x01, sizeof(u8)*pIter->nTblCol);
+    }
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", zIdx)
+    );
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+      int iCid = sqlite3_column_int(pXInfo, 1);
+      if( iCid>=0 ) pIter->abIndexed[iCid] = 1;
+      if( iCid==-2 ){
+        memset(pIter->abIndexed, 0x01, sizeof(u8)*pIter->nTblCol);
+      }
+    }
+    rbuFinalize(p, pXInfo);
+    bIndex = 1;
+    pIter->nIndex++;
+  }
+
+  if( pIter->eType==RBU_PK_WITHOUT_ROWID ){
+    /* "PRAGMA index_list" includes the main PK b-tree */
+    pIter->nIndex--;
+  }
+
+  rbuFinalize(p, pList);
+  if( bIndex==0 ) pIter->abIndexed = 0;
+}
+
+
+/*
+** If they are not already populated, populate the pIter->azTblCol[],
+** pIter->abTblPk[], pIter->nTblCol and pIter->bRowid variables according to
+** the table (not index) that the iterator currently points to.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise. If
+** an error does occur, an error code and error message are also left in
+** the RBU handle.
+*/
+static int rbuObjIterCacheTableInfo(sqlite3rbu *p, RbuObjIter *pIter){
+  if( pIter->azTblCol==0 ){
+    sqlite3_stmt *pStmt = 0;
+    int nCol = 0;
+    int i;                        /* for() loop iterator variable */
+    int bRbuRowid = 0;            /* If input table has column "rbu_rowid" */
+    int iOrder = 0;
+    int iTnum = 0;
+
+    /* Figure out the type of table this step will deal with. */
+    assert( pIter->eType==0 );
+    rbuTableType(p, pIter->zTbl, &pIter->eType, &iTnum, &pIter->iPkTnum);
+    if( p->rc==SQLITE_OK && pIter->eType==RBU_PK_NOTABLE ){
+      p->rc = SQLITE_ERROR;
+      p->zErrmsg = sqlite3_mprintf("no such table: %s", pIter->zTbl);
+    }
+    if( p->rc ) return p->rc;
+    if( pIter->zIdx==0 ) pIter->iTnum = iTnum;
+
+    assert( pIter->eType==RBU_PK_NONE || pIter->eType==RBU_PK_IPK
+         || pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_WITHOUT_ROWID
+         || pIter->eType==RBU_PK_VTAB
+    );
+
+    /* Populate the azTblCol[] and nTblCol variables based on the columns
+    ** of the input table. Ignore any input table columns that begin with
+    ** "rbu_".  */
+    p->rc = prepareFreeAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
+        sqlite3_mprintf("SELECT * FROM '%q'", pIter->zDataTbl)
+    );
+    if( p->rc==SQLITE_OK ){
+      nCol = sqlite3_column_count(pStmt);
+      rbuAllocateIterArrays(p, pIter, nCol);
+    }
+    for(i=0; p->rc==SQLITE_OK && i<nCol; i++){
+      const char *zName = (const char*)sqlite3_column_name(pStmt, i);
+      if( sqlite3_strnicmp("rbu_", zName, 4) ){
+        char *zCopy = rbuStrndup(zName, &p->rc);
+        pIter->aiSrcOrder[pIter->nTblCol] = pIter->nTblCol;
+        pIter->azTblCol[pIter->nTblCol++] = zCopy;
+      }
+      else if( 0==sqlite3_stricmp("rbu_rowid", zName) ){
+        bRbuRowid = 1;
+      }
+    }
+    sqlite3_finalize(pStmt);
+    pStmt = 0;
+
+    if( p->rc==SQLITE_OK
+     && rbuIsVacuum(p)==0
+     && bRbuRowid!=(pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE)
+    ){
+      p->rc = SQLITE_ERROR;
+      p->zErrmsg = sqlite3_mprintf(
+          "table %q %s rbu_rowid column", pIter->zDataTbl,
+          (bRbuRowid ? "may not have" : "requires")
+      );
+    }
+
+    /* Check that all non-HIDDEN columns in the destination table are also
+    ** present in the input table. Populate the abTblPk[], azTblType[] and
+    ** aiTblOrder[] arrays at the same time.  */
+    if( p->rc==SQLITE_OK ){
+      p->rc = prepareFreeAndCollectError(p->dbMain, &pStmt, &p->zErrmsg,
+          sqlite3_mprintf("PRAGMA table_info(%Q)", pIter->zTbl)
+      );
+    }
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      const char *zName = (const char*)sqlite3_column_text(pStmt, 1);
+      if( zName==0 ) break;  /* An OOM - finalize() below returns S_NOMEM */
+      for(i=iOrder; i<pIter->nTblCol; i++){
+        if( 0==strcmp(zName, pIter->azTblCol[i]) ) break;
+      }
+      if( i==pIter->nTblCol ){
+        p->rc = SQLITE_ERROR;
+        p->zErrmsg = sqlite3_mprintf("column missing from %q: %s",
+            pIter->zDataTbl, zName
+        );
+      }else{
+        int iPk = sqlite3_column_int(pStmt, 5);
+        int bNotNull = sqlite3_column_int(pStmt, 3);
+        const char *zType = (const char*)sqlite3_column_text(pStmt, 2);
+
+        if( i!=iOrder ){
+          SWAP(int, pIter->aiSrcOrder[i], pIter->aiSrcOrder[iOrder]);
+          SWAP(char*, pIter->azTblCol[i], pIter->azTblCol[iOrder]);
+        }
+
+        pIter->azTblType[iOrder] = rbuStrndup(zType, &p->rc);
+        assert( iPk>=0 );
+        pIter->abTblPk[iOrder] = (u8)iPk;
+        pIter->abNotNull[iOrder] = (u8)bNotNull || (iPk!=0);
+        iOrder++;
+      }
+    }
+
+    rbuFinalize(p, pStmt);
+    rbuObjIterCacheIndexedCols(p, pIter);
+    assert( pIter->eType!=RBU_PK_VTAB || pIter->abIndexed==0 );
+    assert( pIter->eType!=RBU_PK_VTAB || pIter->nIndex==0 );
+  }
+
+  return p->rc;
+}
+
+/*
+** This function constructs and returns a pointer to a nul-terminated
+** string containing some SQL clause or list based on one or more of the
+** column names currently stored in the pIter->azTblCol[] array.
+*/
+static char *rbuObjIterGetCollist(
+  sqlite3rbu *p,                  /* RBU object */
+  RbuObjIter *pIter               /* Object iterator for column names */
+){
+  char *zList = 0;
+  const char *zSep = "";
+  int i;
+  for(i=0; i<pIter->nTblCol; i++){
+    const char *z = pIter->azTblCol[i];
+    zList = rbuMPrintf(p, "%z%s\"%w\"", zList, zSep, z);
+    zSep = ", ";
+  }
+  return zList;
+}
+
+/*
+** Return a comma separated list of the quoted PRIMARY KEY column names,
+** in order, for the current table. Before each column name, add the text
+** zPre. After each column name, add the zPost text. Use zSeparator as
+** the separator text (usually ", ").
+*/
+static char *rbuObjIterGetPkList(
+  sqlite3rbu *p,                  /* RBU object */
+  RbuObjIter *pIter,              /* Object iterator for column names */
+  const char *zPre,               /* Before each quoted column name */
+  const char *zSeparator,         /* Separator to use between columns */
+  const char *zPost               /* After each quoted column name */
+){
+  int iPk = 1;
+  char *zRet = 0;
+  const char *zSep = "";
+  while( 1 ){
+    int i;
+    for(i=0; i<pIter->nTblCol; i++){
+      if( (int)pIter->abTblPk[i]==iPk ){
+        const char *zCol = pIter->azTblCol[i];
+        zRet = rbuMPrintf(p, "%z%s%s\"%w\"%s", zRet, zSep, zPre, zCol, zPost);
+        zSep = zSeparator;
+        break;
+      }
+    }
+    if( i==pIter->nTblCol ) break;
+    iPk++;
+  }
+  return zRet;
+}
+
+/*
+** This function is called as part of restarting an RBU vacuum within
+** stage 1 of the process (while the *-oal file is being built) while
+** updating a table (not an index). The table may be a rowid table or
+** a WITHOUT ROWID table. It queries the target database to find the
+** largest key that has already been written to the target table and
+** constructs a WHERE clause that can be used to extract the remaining
+** rows from the source table. For a rowid table, the WHERE clause
+** is of the form:
+**
+**     "WHERE _rowid_ > ?"
+**
+** and for WITHOUT ROWID tables:
+**
+**     "WHERE (key1, key2) > (?, ?)"
+**
+** Instead of "?" placeholders, the actual WHERE clauses created by
+** this function contain literal SQL values.
+*/
+static char *rbuVacuumTableStart(
+  sqlite3rbu *p,                  /* RBU handle */
+  RbuObjIter *pIter,              /* RBU iterator object */
+  int bRowid,                     /* True for a rowid table */
+  const char *zWrite              /* Target table name prefix */
+){
+  sqlite3_stmt *pMax = 0;
+  char *zRet = 0;
+  if( bRowid ){
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pMax, &p->zErrmsg,
+        sqlite3_mprintf(
+          "SELECT max(_rowid_) FROM \"%s%w\"", zWrite, pIter->zTbl
+        )
+    );
+    if( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pMax) ){
+      sqlite3_int64 iMax = sqlite3_column_int64(pMax, 0);
+      zRet = rbuMPrintf(p, " WHERE _rowid_ > %lld ", iMax);
+    }
+    rbuFinalize(p, pMax);
+  }else{
+    char *zOrder = rbuObjIterGetPkList(p, pIter, "", ", ", " DESC");
+    char *zSelect = rbuObjIterGetPkList(p, pIter, "quote(", "||','||", ")");
+    char *zList = rbuObjIterGetPkList(p, pIter, "", ", ", "");
+
+    if( p->rc==SQLITE_OK ){
+      p->rc = prepareFreeAndCollectError(p->dbMain, &pMax, &p->zErrmsg,
+          sqlite3_mprintf(
+            "SELECT %s FROM \"%s%w\" ORDER BY %s LIMIT 1",
+                zSelect, zWrite, pIter->zTbl, zOrder
+          )
+      );
+      if( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pMax) ){
+        const char *zVal = (const char*)sqlite3_column_text(pMax, 0);
+        zRet = rbuMPrintf(p, " WHERE (%s) > (%s) ", zList, zVal);
+      }
+      rbuFinalize(p, pMax);
+    }
+
+    sqlite3_free(zOrder);
+    sqlite3_free(zSelect);
+    sqlite3_free(zList);
+  }
+  return zRet;
+}
+
+/*
+** This function is called as part of restating an RBU vacuum when the
+** current operation is writing content to an index. If possible, it
+** queries the target index b-tree for the largest key already written to
+** it, then composes and returns an expression that can be used in a WHERE
+** clause to select the remaining required rows from the source table.
+** It is only possible to return such an expression if:
+**
+**   * The index contains no DESC columns, and
+**   * The last key written to the index before the operation was
+**     suspended does not contain any NULL values.
+**
+** The expression is of the form:
+**
+**   (index-field1, index-field2, ...) > (?, ?, ...)
+**
+** except that the "?" placeholders are replaced with literal values.
+**
+** If the expression cannot be created, NULL is returned. In this case,
+** the caller has to use an OFFSET clause to extract only the required
+** rows from the sourct table, just as it does for an RBU update operation.
+*/
+static char *rbuVacuumIndexStart(
+  sqlite3rbu *p,                  /* RBU handle */
+  RbuObjIter *pIter               /* RBU iterator object */
+){
+  char *zOrder = 0;
+  char *zLhs = 0;
+  char *zSelect = 0;
+  char *zVector = 0;
+  char *zRet = 0;
+  int bFailed = 0;
+  const char *zSep = "";
+  int iCol = 0;
+  sqlite3_stmt *pXInfo = 0;
+
+  p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+      sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", pIter->zIdx)
+  );
+  while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+    int iCid = sqlite3_column_int(pXInfo, 1);
+    const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
+    const char *zCol;
+    if( sqlite3_column_int(pXInfo, 3) ){
+      bFailed = 1;
+      break;
+    }
+
+    if( iCid<0 ){
+      if( pIter->eType==RBU_PK_IPK ){
+        int i;
+        for(i=0; pIter->abTblPk[i]==0; i++);
+        assert( i<pIter->nTblCol );
+        zCol = pIter->azTblCol[i];
+      }else{
+        zCol = "_rowid_";
+      }
+    }else{
+      zCol = pIter->azTblCol[iCid];
+    }
+
+    zLhs = rbuMPrintf(p, "%z%s \"%w\" COLLATE %Q",
+        zLhs, zSep, zCol, zCollate
+        );
+    zOrder = rbuMPrintf(p, "%z%s \"rbu_imp_%d%w\" COLLATE %Q DESC",
+        zOrder, zSep, iCol, zCol, zCollate
+        );
+    zSelect = rbuMPrintf(p, "%z%s quote(\"rbu_imp_%d%w\")",
+        zSelect, zSep, iCol, zCol
+        );
+    zSep = ", ";
+    iCol++;
+  }
+  rbuFinalize(p, pXInfo);
+  if( bFailed ) goto index_start_out;
+
+  if( p->rc==SQLITE_OK ){
+    sqlite3_stmt *pSel = 0;
+
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pSel, &p->zErrmsg,
+        sqlite3_mprintf("SELECT %s FROM \"rbu_imp_%w\" ORDER BY %s LIMIT 1",
+          zSelect, pIter->zTbl, zOrder
+        )
+    );
+    if( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSel) ){
+      zSep = "";
+      for(iCol=0; iCol<pIter->nCol; iCol++){
+        const char *zQuoted = (const char*)sqlite3_column_text(pSel, iCol);
+        if( zQuoted==0 ){
+          p->rc = SQLITE_NOMEM;
+        }else if( zQuoted[0]=='N' ){
+          bFailed = 1;
+          break;
+        }
+        zVector = rbuMPrintf(p, "%z%s%s", zVector, zSep, zQuoted);
+        zSep = ", ";
+      }
+
+      if( !bFailed ){
+        zRet = rbuMPrintf(p, "(%s) > (%s)", zLhs, zVector);
+      }
+    }
+    rbuFinalize(p, pSel);
+  }
+
+ index_start_out:
+  sqlite3_free(zOrder);
+  sqlite3_free(zSelect);
+  sqlite3_free(zVector);
+  sqlite3_free(zLhs);
+  return zRet;
+}
+
+/*
+** This function is used to create a SELECT list (the list of SQL
+** expressions that follows a SELECT keyword) for a SELECT statement
+** used to read from an data_xxx or rbu_tmp_xxx table while updating the
+** index object currently indicated by the iterator object passed as the
+** second argument. A "PRAGMA index_xinfo = <idxname>" statement is used
+** to obtain the required information.
+**
+** If the index is of the following form:
+**
+**   CREATE INDEX i1 ON t1(c, b COLLATE nocase);
+**
+** and "t1" is a table with an explicit INTEGER PRIMARY KEY column
+** "ipk", the returned string is:
+**
+**   "`c` COLLATE 'BINARY', `b` COLLATE 'NOCASE', `ipk` COLLATE 'BINARY'"
+**
+** As well as the returned string, three other malloc'd strings are
+** returned via output parameters. As follows:
+**
+**   pzImposterCols: ...
+**   pzImposterPk: ...
+**   pzWhere: ...
+*/
+static char *rbuObjIterGetIndexCols(
+  sqlite3rbu *p,                  /* RBU object */
+  RbuObjIter *pIter,              /* Object iterator for column names */
+  char **pzImposterCols,          /* OUT: Columns for imposter table */
+  char **pzImposterPk,            /* OUT: Imposter PK clause */
+  char **pzWhere,                 /* OUT: WHERE clause */
+  int *pnBind                     /* OUT: Trbul number of columns */
+){
+  int rc = p->rc;                 /* Error code */
+  int rc2;                        /* sqlite3_finalize() return code */
+  char *zRet = 0;                 /* String to return */
+  char *zImpCols = 0;             /* String to return via *pzImposterCols */
+  char *zImpPK = 0;               /* String to return via *pzImposterPK */
+  char *zWhere = 0;               /* String to return via *pzWhere */
+  int nBind = 0;                  /* Value to return via *pnBind */
+  const char *zCom = "";          /* Set to ", " later on */
+  const char *zAnd = "";          /* Set to " AND " later on */
+  sqlite3_stmt *pXInfo = 0;       /* PRAGMA index_xinfo = ? */
+
+  if( rc==SQLITE_OK ){
+    assert( p->zErrmsg==0 );
+    rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", pIter->zIdx)
+    );
+  }
+
+  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+    int iCid = sqlite3_column_int(pXInfo, 1);
+    int bDesc = sqlite3_column_int(pXInfo, 3);
+    const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
+    const char *zCol = 0;
+    const char *zType;
+
+    if( iCid==-2 ){
+      int iSeq = sqlite3_column_int(pXInfo, 0);
+      zRet = sqlite3_mprintf("%z%s(%.*s) COLLATE %Q", zRet, zCom,
+          pIter->aIdxCol[iSeq].nSpan, pIter->aIdxCol[iSeq].zSpan, zCollate
+      );
+      zType = "";
+    }else {
+      if( iCid<0 ){
+        /* An integer primary key. If the table has an explicit IPK, use
+        ** its name. Otherwise, use "rbu_rowid".  */
+        if( pIter->eType==RBU_PK_IPK ){
+          int i;
+          for(i=0; pIter->abTblPk[i]==0; i++);
+          assert( i<pIter->nTblCol );
+          zCol = pIter->azTblCol[i];
+        }else if( rbuIsVacuum(p) ){
+          zCol = "_rowid_";
+        }else{
+          zCol = "rbu_rowid";
+        }
+        zType = "INTEGER";
+      }else{
+        zCol = pIter->azTblCol[iCid];
+        zType = pIter->azTblType[iCid];
+      }
+      zRet = sqlite3_mprintf("%z%s\"%w\" COLLATE %Q", zRet, zCom,zCol,zCollate);
+    }
+
+    if( pIter->bUnique==0 || sqlite3_column_int(pXInfo, 5) ){
+      const char *zOrder = (bDesc ? " DESC" : "");
+      zImpPK = sqlite3_mprintf("%z%s\"rbu_imp_%d%w\"%s",
+          zImpPK, zCom, nBind, zCol, zOrder
+      );
+    }
+    zImpCols = sqlite3_mprintf("%z%s\"rbu_imp_%d%w\" %s COLLATE %Q",
+        zImpCols, zCom, nBind, zCol, zType, zCollate
+    );
+    zWhere = sqlite3_mprintf(
+        "%z%s\"rbu_imp_%d%w\" IS ?", zWhere, zAnd, nBind, zCol
+    );
+    if( zRet==0 || zImpPK==0 || zImpCols==0 || zWhere==0 ) rc = SQLITE_NOMEM;
+    zCom = ", ";
+    zAnd = " AND ";
+    nBind++;
+  }
+
+  rc2 = sqlite3_finalize(pXInfo);
+  if( rc==SQLITE_OK ) rc = rc2;
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(zRet);
+    sqlite3_free(zImpCols);
+    sqlite3_free(zImpPK);
+    sqlite3_free(zWhere);
+    zRet = 0;
+    zImpCols = 0;
+    zImpPK = 0;
+    zWhere = 0;
+    p->rc = rc;
+  }
+
+  *pzImposterCols = zImpCols;
+  *pzImposterPk = zImpPK;
+  *pzWhere = zWhere;
+  *pnBind = nBind;
+  return zRet;
+}
+
+/*
+** Assuming the current table columns are "a", "b" and "c", and the zObj
+** paramter is passed "old", return a string of the form:
+**
+**     "old.a, old.b, old.b"
+**
+** With the column names escaped.
+**
+** For tables with implicit rowids - RBU_PK_EXTERNAL and RBU_PK_NONE, append
+** the text ", old._rowid_" to the returned value.
+*/
+static char *rbuObjIterGetOldlist(
+  sqlite3rbu *p,
+  RbuObjIter *pIter,
+  const char *zObj
+){
+  char *zList = 0;
+  if( p->rc==SQLITE_OK && pIter->abIndexed ){
+    const char *zS = "";
+    int i;
+    for(i=0; i<pIter->nTblCol; i++){
+      if( pIter->abIndexed[i] ){
+        const char *zCol = pIter->azTblCol[i];
+        zList = sqlite3_mprintf("%z%s%s.\"%w\"", zList, zS, zObj, zCol);
+      }else{
+        zList = sqlite3_mprintf("%z%sNULL", zList, zS);
+      }
+      zS = ", ";
+      if( zList==0 ){
+        p->rc = SQLITE_NOMEM;
+        break;
+      }
+    }
+
+    /* For a table with implicit rowids, append "old._rowid_" to the list. */
+    if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
+      zList = rbuMPrintf(p, "%z, %s._rowid_", zList, zObj);
+    }
+  }
+  return zList;
+}
+
+/*
+** Return an expression that can be used in a WHERE clause to match the
+** primary key of the current table. For example, if the table is:
+**
+**   CREATE TABLE t1(a, b, c, PRIMARY KEY(b, c));
+**
+** Return the string:
+**
+**   "b = ?1 AND c = ?2"
+*/
+static char *rbuObjIterGetWhere(
+  sqlite3rbu *p,
+  RbuObjIter *pIter
+){
+  char *zList = 0;
+  if( pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE ){
+    zList = rbuMPrintf(p, "_rowid_ = ?%d", pIter->nTblCol+1);
+  }else if( pIter->eType==RBU_PK_EXTERNAL ){
+    const char *zSep = "";
+    int i;
+    for(i=0; i<pIter->nTblCol; i++){
+      if( pIter->abTblPk[i] ){
+        zList = rbuMPrintf(p, "%z%sc%d=?%d", zList, zSep, i, i+1);
+        zSep = " AND ";
+      }
+    }
+    zList = rbuMPrintf(p,
+        "_rowid_ = (SELECT id FROM rbu_imposter2 WHERE %z)", zList
+    );
+
+  }else{
+    const char *zSep = "";
+    int i;
+    for(i=0; i<pIter->nTblCol; i++){
+      if( pIter->abTblPk[i] ){
+        const char *zCol = pIter->azTblCol[i];
+        zList = rbuMPrintf(p, "%z%s\"%w\"=?%d", zList, zSep, zCol, i+1);
+        zSep = " AND ";
+      }
+    }
+  }
+  return zList;
+}
+
+/*
+** The SELECT statement iterating through the keys for the current object
+** (p->objiter.pSelect) currently points to a valid row. However, there
+** is something wrong with the rbu_control value in the rbu_control value
+** stored in the (p->nCol+1)'th column. Set the error code and error message
+** of the RBU handle to something reflecting this.
+*/
+static void rbuBadControlError(sqlite3rbu *p){
+  p->rc = SQLITE_ERROR;
+  p->zErrmsg = sqlite3_mprintf("invalid rbu_control value");
+}
+
+
+/*
+** Return a nul-terminated string containing the comma separated list of
+** assignments that should be included following the "SET" keyword of
+** an UPDATE statement used to update the table object that the iterator
+** passed as the second argument currently points to if the rbu_control
+** column of the data_xxx table entry is set to zMask.
+**
+** The memory for the returned string is obtained from sqlite3_malloc().
+** It is the responsibility of the caller to eventually free it using
+** sqlite3_free().
+**
+** If an OOM error is encountered when allocating space for the new
+** string, an error code is left in the rbu handle passed as the first
+** argument and NULL is returned. Or, if an error has already occurred
+** when this function is called, NULL is returned immediately, without
+** attempting the allocation or modifying the stored error code.
+*/
+static char *rbuObjIterGetSetlist(
+  sqlite3rbu *p,
+  RbuObjIter *pIter,
+  const char *zMask
+){
+  char *zList = 0;
+  if( p->rc==SQLITE_OK ){
+    int i;
+
+    if( (int)strlen(zMask)!=pIter->nTblCol ){
+      rbuBadControlError(p);
+    }else{
+      const char *zSep = "";
+      for(i=0; i<pIter->nTblCol; i++){
+        char c = zMask[pIter->aiSrcOrder[i]];
+        if( c=='x' ){
+          zList = rbuMPrintf(p, "%z%s\"%w\"=?%d",
+              zList, zSep, pIter->azTblCol[i], i+1
+          );
+          zSep = ", ";
+        }
+        else if( c=='d' ){
+          zList = rbuMPrintf(p, "%z%s\"%w\"=rbu_delta(\"%w\", ?%d)",
+              zList, zSep, pIter->azTblCol[i], pIter->azTblCol[i], i+1
+          );
+          zSep = ", ";
+        }
+        else if( c=='f' ){
+          zList = rbuMPrintf(p, "%z%s\"%w\"=rbu_fossil_delta(\"%w\", ?%d)",
+              zList, zSep, pIter->azTblCol[i], pIter->azTblCol[i], i+1
+          );
+          zSep = ", ";
+        }
+      }
+    }
+  }
+  return zList;
+}
+
+/*
+** Return a nul-terminated string consisting of nByte comma separated
+** "?" expressions. For example, if nByte is 3, return a pointer to
+** a buffer containing the string "?,?,?".
+**
+** The memory for the returned string is obtained from sqlite3_malloc().
+** It is the responsibility of the caller to eventually free it using
+** sqlite3_free().
+**
+** If an OOM error is encountered when allocating space for the new
+** string, an error code is left in the rbu handle passed as the first
+** argument and NULL is returned. Or, if an error has already occurred
+** when this function is called, NULL is returned immediately, without
+** attempting the allocation or modifying the stored error code.
+*/
+static char *rbuObjIterGetBindlist(sqlite3rbu *p, int nBind){
+  char *zRet = 0;
+  sqlite3_int64 nByte = 2*(sqlite3_int64)nBind + 1;
+
+  zRet = (char*)rbuMalloc(p, nByte);
+  if( zRet ){
+    int i;
+    for(i=0; i<nBind; i++){
+      zRet[i*2] = '?';
+      zRet[i*2+1] = (i+1==nBind) ? '\0' : ',';
+    }
+  }
+  return zRet;
+}
+
+/*
+** The iterator currently points to a table (not index) of type
+** RBU_PK_WITHOUT_ROWID. This function creates the PRIMARY KEY
+** declaration for the corresponding imposter table. For example,
+** if the iterator points to a table created as:
+**
+**   CREATE TABLE t1(a, b, c, PRIMARY KEY(b, a DESC)) WITHOUT ROWID
+**
+** this function returns:
+**
+**   PRIMARY KEY("b", "a" DESC)
+*/
+static char *rbuWithoutRowidPK(sqlite3rbu *p, RbuObjIter *pIter){
+  char *z = 0;
+  assert( pIter->zIdx==0 );
+  if( p->rc==SQLITE_OK ){
+    const char *zSep = "PRIMARY KEY(";
+    sqlite3_stmt *pXList = 0;     /* PRAGMA index_list = (pIter->zTbl) */
+    sqlite3_stmt *pXInfo = 0;     /* PRAGMA index_xinfo = <pk-index> */
+
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pXList, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.index_list = %Q", pIter->zTbl)
+    );
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXList) ){
+      const char *zOrig = (const char*)sqlite3_column_text(pXList,3);
+      if( zOrig && strcmp(zOrig, "pk")==0 ){
+        const char *zIdx = (const char*)sqlite3_column_text(pXList,1);
+        if( zIdx ){
+          p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+              sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", zIdx)
+          );
+        }
+        break;
+      }
+    }
+    rbuFinalize(p, pXList);
+
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+      if( sqlite3_column_int(pXInfo, 5) ){
+        /* int iCid = sqlite3_column_int(pXInfo, 0); */
+        const char *zCol = (const char*)sqlite3_column_text(pXInfo, 2);
+        const char *zDesc = sqlite3_column_int(pXInfo, 3) ? " DESC" : "";
+        z = rbuMPrintf(p, "%z%s\"%w\"%s", z, zSep, zCol, zDesc);
+        zSep = ", ";
+      }
+    }
+    z = rbuMPrintf(p, "%z)", z);
+    rbuFinalize(p, pXInfo);
+  }
+  return z;
+}
+
+/*
+** This function creates the second imposter table used when writing to
+** a table b-tree where the table has an external primary key. If the
+** iterator passed as the second argument does not currently point to
+** a table (not index) with an external primary key, this function is a
+** no-op.
+**
+** Assuming the iterator does point to a table with an external PK, this
+** function creates a WITHOUT ROWID imposter table named "rbu_imposter2"
+** used to access that PK index. For example, if the target table is
+** declared as follows:
+**
+**   CREATE TABLE t1(a, b TEXT, c REAL, PRIMARY KEY(b, c));
+**
+** then the imposter table schema is:
+**
+**   CREATE TABLE rbu_imposter2(c1 TEXT, c2 REAL, id INTEGER) WITHOUT ROWID;
+**
+*/
+static void rbuCreateImposterTable2(sqlite3rbu *p, RbuObjIter *pIter){
+  if( p->rc==SQLITE_OK && pIter->eType==RBU_PK_EXTERNAL ){
+    int tnum = pIter->iPkTnum;    /* Root page of PK index */
+    sqlite3_stmt *pQuery = 0;     /* SELECT name ... WHERE rootpage = $tnum */
+    const char *zIdx = 0;         /* Name of PK index */
+    sqlite3_stmt *pXInfo = 0;     /* PRAGMA main.index_xinfo = $zIdx */
+    const char *zComma = "";
+    char *zCols = 0;              /* Used to build up list of table cols */
+    char *zPk = 0;                /* Used to build up table PK declaration */
+
+    /* Figure out the name of the primary key index for the current table.
+    ** This is needed for the argument to "PRAGMA index_xinfo". Set
+    ** zIdx to point to a nul-terminated string containing this name. */
+    p->rc = prepareAndCollectError(p->dbMain, &pQuery, &p->zErrmsg,
+        "SELECT name FROM sqlite_schema WHERE rootpage = ?"
+    );
+    if( p->rc==SQLITE_OK ){
+      sqlite3_bind_int(pQuery, 1, tnum);
+      if( SQLITE_ROW==sqlite3_step(pQuery) ){
+        zIdx = (const char*)sqlite3_column_text(pQuery, 0);
+      }
+    }
+    if( zIdx ){
+      p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+          sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", zIdx)
+      );
+    }
+    rbuFinalize(p, pQuery);
+
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+      int bKey = sqlite3_column_int(pXInfo, 5);
+      if( bKey ){
+        int iCid = sqlite3_column_int(pXInfo, 1);
+        int bDesc = sqlite3_column_int(pXInfo, 3);
+        const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
+        zCols = rbuMPrintf(p, "%z%sc%d %s COLLATE %Q", zCols, zComma,
+            iCid, pIter->azTblType[iCid], zCollate
+        );
+        zPk = rbuMPrintf(p, "%z%sc%d%s", zPk, zComma, iCid, bDesc?" DESC":"");
+        zComma = ", ";
+      }
+    }
+    zCols = rbuMPrintf(p, "%z, id INTEGER", zCols);
+    rbuFinalize(p, pXInfo);
+
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 1, tnum);
+    rbuMPrintfExec(p, p->dbMain,
+        "CREATE TABLE rbu_imposter2(%z, PRIMARY KEY(%z)) WITHOUT ROWID",
+        zCols, zPk
+    );
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 0);
+  }
+}
+
+/*
+** If an error has already occurred when this function is called, it
+** immediately returns zero (without doing any work). Or, if an error
+** occurs during the execution of this function, it sets the error code
+** in the sqlite3rbu object indicated by the first argument and returns
+** zero.
+**
+** The iterator passed as the second argument is guaranteed to point to
+** a table (not an index) when this function is called. This function
+** attempts to create any imposter table required to write to the main
+** table b-tree of the table before returning. Non-zero is returned if
+** an imposter table are created, or zero otherwise.
+**
+** An imposter table is required in all cases except RBU_PK_VTAB. Only
+** virtual tables are written to directly. The imposter table has the
+** same schema as the actual target table (less any UNIQUE constraints).
+** More precisely, the "same schema" means the same columns, types,
+** collation sequences. For tables that do not have an external PRIMARY
+** KEY, it also means the same PRIMARY KEY declaration.
+*/
+static void rbuCreateImposterTable(sqlite3rbu *p, RbuObjIter *pIter){
+  if( p->rc==SQLITE_OK && pIter->eType!=RBU_PK_VTAB ){
+    int tnum = pIter->iTnum;
+    const char *zComma = "";
+    char *zSql = 0;
+    int iCol;
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 1);
+
+    for(iCol=0; p->rc==SQLITE_OK && iCol<pIter->nTblCol; iCol++){
+      const char *zPk = "";
+      const char *zCol = pIter->azTblCol[iCol];
+      const char *zColl = 0;
+
+      p->rc = sqlite3_table_column_metadata(
+          p->dbMain, "main", pIter->zTbl, zCol, 0, &zColl, 0, 0, 0
+      );
+
+      if( pIter->eType==RBU_PK_IPK && pIter->abTblPk[iCol] ){
+        /* If the target table column is an "INTEGER PRIMARY KEY", add
+        ** "PRIMARY KEY" to the imposter table column declaration. */
+        zPk = "PRIMARY KEY ";
+      }
+      zSql = rbuMPrintf(p, "%z%s\"%w\" %s %sCOLLATE %Q%s",
+          zSql, zComma, zCol, pIter->azTblType[iCol], zPk, zColl,
+          (pIter->abNotNull[iCol] ? " NOT NULL" : "")
+      );
+      zComma = ", ";
+    }
+
+    if( pIter->eType==RBU_PK_WITHOUT_ROWID ){
+      char *zPk = rbuWithoutRowidPK(p, pIter);
+      if( zPk ){
+        zSql = rbuMPrintf(p, "%z, %z", zSql, zPk);
+      }
+    }
+
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 1, tnum);
+    rbuMPrintfExec(p, p->dbMain, "CREATE TABLE \"rbu_imp_%w\"(%z)%s",
+        pIter->zTbl, zSql,
+        (pIter->eType==RBU_PK_WITHOUT_ROWID ? " WITHOUT ROWID" : "")
+    );
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 0);
+  }
+}
+
+/*
+** Prepare a statement used to insert rows into the "rbu_tmp_xxx" table.
+** Specifically a statement of the form:
+**
+**     INSERT INTO rbu_tmp_xxx VALUES(?, ?, ? ...);
+**
+** The number of bound variables is equal to the number of columns in
+** the target table, plus one (for the rbu_control column), plus one more
+** (for the rbu_rowid column) if the target table is an implicit IPK or
+** virtual table.
+*/
+static void rbuObjIterPrepareTmpInsert(
+  sqlite3rbu *p,
+  RbuObjIter *pIter,
+  const char *zCollist,
+  const char *zRbuRowid
+){
+  int bRbuRowid = (pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE);
+  char *zBind = rbuObjIterGetBindlist(p, pIter->nTblCol + 1 + bRbuRowid);
+  if( zBind ){
+    assert( pIter->pTmpInsert==0 );
+    p->rc = prepareFreeAndCollectError(
+        p->dbRbu, &pIter->pTmpInsert, &p->zErrmsg, sqlite3_mprintf(
+          "INSERT INTO %s.'rbu_tmp_%q'(rbu_control,%s%s) VALUES(%z)",
+          p->zStateDb, pIter->zDataTbl, zCollist, zRbuRowid, zBind
+    ));
+  }
+}
+
+static void rbuTmpInsertFunc(
+  sqlite3_context *pCtx,
+  int nVal,
+  sqlite3_value **apVal
+){
+  sqlite3rbu *p = sqlite3_user_data(pCtx);
+  int rc = SQLITE_OK;
+  int i;
+
+  assert( sqlite3_value_int(apVal[0])!=0
+      || p->objiter.eType==RBU_PK_EXTERNAL
+      || p->objiter.eType==RBU_PK_NONE
+  );
+  if( sqlite3_value_int(apVal[0])!=0 ){
+    p->nPhaseOneStep += p->objiter.nIndex;
+  }
+
+  for(i=0; rc==SQLITE_OK && i<nVal; i++){
+    rc = sqlite3_bind_value(p->objiter.pTmpInsert, i+1, apVal[i]);
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3_step(p->objiter.pTmpInsert);
+    rc = sqlite3_reset(p->objiter.pTmpInsert);
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+  }
+}
+
+static char *rbuObjIterGetIndexWhere(sqlite3rbu *p, RbuObjIter *pIter){
+  sqlite3_stmt *pStmt = 0;
+  int rc = p->rc;
+  char *zRet = 0;
+
+  assert( pIter->zIdxSql==0 && pIter->nIdxCol==0 && pIter->aIdxCol==0 );
+
+  if( rc==SQLITE_OK ){
+    rc = prepareAndCollectError(p->dbMain, &pStmt, &p->zErrmsg,
+        "SELECT trim(sql) FROM sqlite_schema WHERE type='index' AND name=?"
+    );
+  }
+  if( rc==SQLITE_OK ){
+    int rc2;
+    rc = sqlite3_bind_text(pStmt, 1, pIter->zIdx, -1, SQLITE_STATIC);
+    if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      char *zSql = (char*)sqlite3_column_text(pStmt, 0);
+      if( zSql ){
+        pIter->zIdxSql = zSql = rbuStrndup(zSql, &rc);
+      }
+      if( zSql ){
+        int nParen = 0;           /* Number of open parenthesis */
+        int i;
+        int iIdxCol = 0;
+        int nIdxAlloc = 0;
+        for(i=0; zSql[i]; i++){
+          char c = zSql[i];
+
+          /* If necessary, grow the pIter->aIdxCol[] array */
+          if( iIdxCol==nIdxAlloc ){
+            RbuSpan *aIdxCol = (RbuSpan*)sqlite3_realloc(
+                pIter->aIdxCol, (nIdxAlloc+16)*sizeof(RbuSpan)
+            );
+            if( aIdxCol==0 ){
+              rc = SQLITE_NOMEM;
+              break;
+            }
+            pIter->aIdxCol = aIdxCol;
+            nIdxAlloc += 16;
+          }
+
+          if( c=='(' ){
+            if( nParen==0 ){
+              assert( iIdxCol==0 );
+              pIter->aIdxCol[0].zSpan = &zSql[i+1];
+            }
+            nParen++;
+          }
+          else if( c==')' ){
+            nParen--;
+            if( nParen==0 ){
+              int nSpan = (int)(&zSql[i] - pIter->aIdxCol[iIdxCol].zSpan);
+              pIter->aIdxCol[iIdxCol++].nSpan = nSpan;
+              i++;
+              break;
+            }
+          }else if( c==',' && nParen==1 ){
+            int nSpan = (int)(&zSql[i] - pIter->aIdxCol[iIdxCol].zSpan);
+            pIter->aIdxCol[iIdxCol++].nSpan = nSpan;
+            pIter->aIdxCol[iIdxCol].zSpan = &zSql[i+1];
+          }else if( c=='"' || c=='\'' || c=='`' ){
+            for(i++; 1; i++){
+              if( zSql[i]==c ){
+                if( zSql[i+1]!=c ) break;
+                i++;
+              }
+            }
+          }else if( c=='[' ){
+            for(i++; 1; i++){
+              if( zSql[i]==']' ) break;
+            }
+          }else if( c=='-' && zSql[i+1]=='-' ){
+            for(i=i+2; zSql[i] && zSql[i]!='\n'; i++);
+            if( zSql[i]=='\0' ) break;
+          }else if( c=='/' && zSql[i+1]=='*' ){
+            for(i=i+2; zSql[i] && (zSql[i]!='*' || zSql[i+1]!='/'); i++);
+            if( zSql[i]=='\0' ) break;
+            i++;
+          }
+        }
+        if( zSql[i] ){
+          zRet = rbuStrndup(&zSql[i], &rc);
+        }
+        pIter->nIdxCol = iIdxCol;
+      }
+    }
+
+    rc2 = sqlite3_finalize(pStmt);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  p->rc = rc;
+  return zRet;
+}
+
+/*
+** Ensure that the SQLite statement handles required to update the
+** target database object currently indicated by the iterator passed
+** as the second argument are available.
+*/
+static int rbuObjIterPrepareAll(
+  sqlite3rbu *p,
+  RbuObjIter *pIter,
+  int nOffset                     /* Add "LIMIT -1 OFFSET $nOffset" to SELECT */
+){
+  assert( pIter->bCleanup==0 );
+  if( pIter->pSelect==0 && rbuObjIterCacheTableInfo(p, pIter)==SQLITE_OK ){
+    const int tnum = pIter->iTnum;
+    char *zCollist = 0;           /* List of indexed columns */
+    char **pz = &p->zErrmsg;
+    const char *zIdx = pIter->zIdx;
+    char *zLimit = 0;
+
+    if( nOffset ){
+      zLimit = sqlite3_mprintf(" LIMIT -1 OFFSET %d", nOffset);
+      if( !zLimit ) p->rc = SQLITE_NOMEM;
+    }
+
+    if( zIdx ){
+      const char *zTbl = pIter->zTbl;
+      char *zImposterCols = 0;    /* Columns for imposter table */
+      char *zImposterPK = 0;      /* Primary key declaration for imposter */
+      char *zWhere = 0;           /* WHERE clause on PK columns */
+      char *zBind = 0;
+      char *zPart = 0;
+      int nBind = 0;
+
+      assert( pIter->eType!=RBU_PK_VTAB );
+      zPart = rbuObjIterGetIndexWhere(p, pIter);
+      zCollist = rbuObjIterGetIndexCols(
+          p, pIter, &zImposterCols, &zImposterPK, &zWhere, &nBind
+      );
+      zBind = rbuObjIterGetBindlist(p, nBind);
+
+      /* Create the imposter table used to write to this index. */
+      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 1);
+      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 1,tnum);
+      rbuMPrintfExec(p, p->dbMain,
+          "CREATE TABLE \"rbu_imp_%w\"( %s, PRIMARY KEY( %s ) ) WITHOUT ROWID",
+          zTbl, zImposterCols, zImposterPK
+      );
+      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 0);
+
+      /* Create the statement to insert index entries */
+      pIter->nCol = nBind;
+      if( p->rc==SQLITE_OK ){
+        p->rc = prepareFreeAndCollectError(
+            p->dbMain, &pIter->pInsert, &p->zErrmsg,
+          sqlite3_mprintf("INSERT INTO \"rbu_imp_%w\" VALUES(%s)", zTbl, zBind)
+        );
+      }
+
+      /* And to delete index entries */
+      if( rbuIsVacuum(p)==0 && p->rc==SQLITE_OK ){
+        p->rc = prepareFreeAndCollectError(
+            p->dbMain, &pIter->pDelete, &p->zErrmsg,
+          sqlite3_mprintf("DELETE FROM \"rbu_imp_%w\" WHERE %s", zTbl, zWhere)
+        );
+      }
+
+      /* Create the SELECT statement to read keys in sorted order */
+      if( p->rc==SQLITE_OK ){
+        char *zSql;
+        if( rbuIsVacuum(p) ){
+          char *zStart = 0;
+          if( nOffset ){
+            zStart = rbuVacuumIndexStart(p, pIter);
+            if( zStart ){
+              sqlite3_free(zLimit);
+              zLimit = 0;
+            }
+          }
+
+          zSql = sqlite3_mprintf(
+              "SELECT %s, 0 AS rbu_control FROM '%q' %s %s %s ORDER BY %s%s",
+              zCollist,
+              pIter->zDataTbl,
+              zPart,
+              (zStart ? (zPart ? "AND" : "WHERE") : ""), zStart,
+              zCollist, zLimit
+          );
+          sqlite3_free(zStart);
+        }else
+
+        if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
+          zSql = sqlite3_mprintf(
+              "SELECT %s, rbu_control FROM %s.'rbu_tmp_%q' %s ORDER BY %s%s",
+              zCollist, p->zStateDb, pIter->zDataTbl,
+              zPart, zCollist, zLimit
+          );
+        }else{
+          zSql = sqlite3_mprintf(
+              "SELECT %s, rbu_control FROM %s.'rbu_tmp_%q' %s "
+              "UNION ALL "
+              "SELECT %s, rbu_control FROM '%q' "
+              "%s %s typeof(rbu_control)='integer' AND rbu_control!=1 "
+              "ORDER BY %s%s",
+              zCollist, p->zStateDb, pIter->zDataTbl, zPart,
+              zCollist, pIter->zDataTbl,
+              zPart,
+              (zPart ? "AND" : "WHERE"),
+              zCollist, zLimit
+          );
+        }
+        if( p->rc==SQLITE_OK ){
+          p->rc = prepareFreeAndCollectError(p->dbRbu,&pIter->pSelect,pz,zSql);
+        }else{
+          sqlite3_free(zSql);
+        }
+      }
+
+      sqlite3_free(zImposterCols);
+      sqlite3_free(zImposterPK);
+      sqlite3_free(zWhere);
+      sqlite3_free(zBind);
+      sqlite3_free(zPart);
+    }else{
+      int bRbuRowid = (pIter->eType==RBU_PK_VTAB)
+                    ||(pIter->eType==RBU_PK_NONE)
+                    ||(pIter->eType==RBU_PK_EXTERNAL && rbuIsVacuum(p));
+      const char *zTbl = pIter->zTbl;       /* Table this step applies to */
+      const char *zWrite;                   /* Imposter table name */
+
+      char *zBindings = rbuObjIterGetBindlist(p, pIter->nTblCol + bRbuRowid);
+      char *zWhere = rbuObjIterGetWhere(p, pIter);
+      char *zOldlist = rbuObjIterGetOldlist(p, pIter, "old");
+      char *zNewlist = rbuObjIterGetOldlist(p, pIter, "new");
+
+      zCollist = rbuObjIterGetCollist(p, pIter);
+      pIter->nCol = pIter->nTblCol;
+
+      /* Create the imposter table or tables (if required). */
+      rbuCreateImposterTable(p, pIter);
+      rbuCreateImposterTable2(p, pIter);
+      zWrite = (pIter->eType==RBU_PK_VTAB ? "" : "rbu_imp_");
+
+      /* Create the INSERT statement to write to the target PK b-tree */
+      if( p->rc==SQLITE_OK ){
+        p->rc = prepareFreeAndCollectError(p->dbMain, &pIter->pInsert, pz,
+            sqlite3_mprintf(
+              "INSERT INTO \"%s%w\"(%s%s) VALUES(%s)",
+              zWrite, zTbl, zCollist, (bRbuRowid ? ", _rowid_" : ""), zBindings
+            )
+        );
+      }
+
+      /* Create the DELETE statement to write to the target PK b-tree.
+      ** Because it only performs INSERT operations, this is not required for
+      ** an rbu vacuum handle.  */
+      if( rbuIsVacuum(p)==0 && p->rc==SQLITE_OK ){
+        p->rc = prepareFreeAndCollectError(p->dbMain, &pIter->pDelete, pz,
+            sqlite3_mprintf(
+              "DELETE FROM \"%s%w\" WHERE %s", zWrite, zTbl, zWhere
+            )
+        );
+      }
+
+      if( rbuIsVacuum(p)==0 && pIter->abIndexed ){
+        const char *zRbuRowid = "";
+        if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
+          zRbuRowid = ", rbu_rowid";
+        }
+
+        /* Create the rbu_tmp_xxx table and the triggers to populate it. */
+        rbuMPrintfExec(p, p->dbRbu,
+            "CREATE TABLE IF NOT EXISTS %s.'rbu_tmp_%q' AS "
+            "SELECT *%s FROM '%q' WHERE 0;"
+            , p->zStateDb, pIter->zDataTbl
+            , (pIter->eType==RBU_PK_EXTERNAL ? ", 0 AS rbu_rowid" : "")
+            , pIter->zDataTbl
+        );
+
+        rbuMPrintfExec(p, p->dbMain,
+            "CREATE TEMP TRIGGER rbu_delete_tr BEFORE DELETE ON \"%s%w\" "
+            "BEGIN "
+            "  SELECT rbu_tmp_insert(3, %s);"
+            "END;"
+
+            "CREATE TEMP TRIGGER rbu_update1_tr BEFORE UPDATE ON \"%s%w\" "
+            "BEGIN "
+            "  SELECT rbu_tmp_insert(3, %s);"
+            "END;"
+
+            "CREATE TEMP TRIGGER rbu_update2_tr AFTER UPDATE ON \"%s%w\" "
+            "BEGIN "
+            "  SELECT rbu_tmp_insert(4, %s);"
+            "END;",
+            zWrite, zTbl, zOldlist,
+            zWrite, zTbl, zOldlist,
+            zWrite, zTbl, zNewlist
+        );
+
+        if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
+          rbuMPrintfExec(p, p->dbMain,
+              "CREATE TEMP TRIGGER rbu_insert_tr AFTER INSERT ON \"%s%w\" "
+              "BEGIN "
+              "  SELECT rbu_tmp_insert(0, %s);"
+              "END;",
+              zWrite, zTbl, zNewlist
+          );
+        }
+
+        rbuObjIterPrepareTmpInsert(p, pIter, zCollist, zRbuRowid);
+      }
+
+      /* Create the SELECT statement to read keys from data_xxx */
+      if( p->rc==SQLITE_OK ){
+        const char *zRbuRowid = "";
+        char *zStart = 0;
+        char *zOrder = 0;
+        if( bRbuRowid ){
+          zRbuRowid = rbuIsVacuum(p) ? ",_rowid_ " : ",rbu_rowid";
+        }
+
+        if( rbuIsVacuum(p) ){
+          if( nOffset ){
+            zStart = rbuVacuumTableStart(p, pIter, bRbuRowid, zWrite);
+            if( zStart ){
+              sqlite3_free(zLimit);
+              zLimit = 0;
+            }
+          }
+          if( bRbuRowid ){
+            zOrder = rbuMPrintf(p, "_rowid_");
+          }else{
+            zOrder = rbuObjIterGetPkList(p, pIter, "", ", ", "");
+          }
+        }
+
+        if( p->rc==SQLITE_OK ){
+          p->rc = prepareFreeAndCollectError(p->dbRbu, &pIter->pSelect, pz,
+              sqlite3_mprintf(
+                "SELECT %s,%s rbu_control%s FROM '%q'%s %s %s %s",
+                zCollist,
+                (rbuIsVacuum(p) ? "0 AS " : ""),
+                zRbuRowid,
+                pIter->zDataTbl, (zStart ? zStart : ""),
+                (zOrder ? "ORDER BY" : ""), zOrder,
+                zLimit
+              )
+          );
+        }
+        sqlite3_free(zStart);
+        sqlite3_free(zOrder);
+      }
+
+      sqlite3_free(zWhere);
+      sqlite3_free(zOldlist);
+      sqlite3_free(zNewlist);
+      sqlite3_free(zBindings);
+    }
+    sqlite3_free(zCollist);
+    sqlite3_free(zLimit);
+  }
+
+  return p->rc;
+}
+
+/*
+** Set output variable *ppStmt to point to an UPDATE statement that may
+** be used to update the imposter table for the main table b-tree of the
+** table object that pIter currently points to, assuming that the
+** rbu_control column of the data_xyz table contains zMask.
+**
+** If the zMask string does not specify any columns to update, then this
+** is not an error. Output variable *ppStmt is set to NULL in this case.
+*/
+static int rbuGetUpdateStmt(
+  sqlite3rbu *p,                  /* RBU handle */
+  RbuObjIter *pIter,              /* Object iterator */
+  const char *zMask,              /* rbu_control value ('x.x.') */
+  sqlite3_stmt **ppStmt           /* OUT: UPDATE statement handle */
+){
+  RbuUpdateStmt **pp;
+  RbuUpdateStmt *pUp = 0;
+  int nUp = 0;
+
+  /* In case an error occurs */
+  *ppStmt = 0;
+
+  /* Search for an existing statement. If one is found, shift it to the front
+  ** of the LRU queue and return immediately. Otherwise, leave nUp pointing
+  ** to the number of statements currently in the cache and pUp to the
+  ** last object in the list.  */
+  for(pp=&pIter->pRbuUpdate; *pp; pp=&((*pp)->pNext)){
+    pUp = *pp;
+    if( strcmp(pUp->zMask, zMask)==0 ){
+      *pp = pUp->pNext;
+      pUp->pNext = pIter->pRbuUpdate;
+      pIter->pRbuUpdate = pUp;
+      *ppStmt = pUp->pUpdate;
+      return SQLITE_OK;
+    }
+    nUp++;
+  }
+  assert( pUp==0 || pUp->pNext==0 );
+
+  if( nUp>=SQLITE_RBU_UPDATE_CACHESIZE ){
+    for(pp=&pIter->pRbuUpdate; *pp!=pUp; pp=&((*pp)->pNext));
+    *pp = 0;
+    sqlite3_finalize(pUp->pUpdate);
+    pUp->pUpdate = 0;
+  }else{
+    pUp = (RbuUpdateStmt*)rbuMalloc(p, sizeof(RbuUpdateStmt)+pIter->nTblCol+1);
+  }
+
+  if( pUp ){
+    char *zWhere = rbuObjIterGetWhere(p, pIter);
+    char *zSet = rbuObjIterGetSetlist(p, pIter, zMask);
+    char *zUpdate = 0;
+
+    pUp->zMask = (char*)&pUp[1];
+    memcpy(pUp->zMask, zMask, pIter->nTblCol);
+    pUp->pNext = pIter->pRbuUpdate;
+    pIter->pRbuUpdate = pUp;
+
+    if( zSet ){
+      const char *zPrefix = "";
+
+      if( pIter->eType!=RBU_PK_VTAB ) zPrefix = "rbu_imp_";
+      zUpdate = sqlite3_mprintf("UPDATE \"%s%w\" SET %s WHERE %s",
+          zPrefix, pIter->zTbl, zSet, zWhere
+      );
+      p->rc = prepareFreeAndCollectError(
+          p->dbMain, &pUp->pUpdate, &p->zErrmsg, zUpdate
+      );
+      *ppStmt = pUp->pUpdate;
+    }
+    sqlite3_free(zWhere);
+    sqlite3_free(zSet);
+  }
+
+  return p->rc;
+}
+
+static sqlite3 *rbuOpenDbhandle(
+  sqlite3rbu *p,
+  const char *zName,
+  int bUseVfs
+){
+  sqlite3 *db = 0;
+  if( p->rc==SQLITE_OK ){
+    const int flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_URI;
+    p->rc = sqlite3_open_v2(zName, &db, flags, bUseVfs ? p->zVfsName : 0);
+    if( p->rc ){
+      p->zErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+      sqlite3_close(db);
+      db = 0;
+    }
+  }
+  return db;
+}
+
+/*
+** Free an RbuState object allocated by rbuLoadState().
+*/
+static void rbuFreeState(RbuState *p){
+  if( p ){
+    sqlite3_free(p->zTbl);
+    sqlite3_free(p->zDataTbl);
+    sqlite3_free(p->zIdx);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Allocate an RbuState object and load the contents of the rbu_state
+** table into it. Return a pointer to the new object. It is the
+** responsibility of the caller to eventually free the object using
+** sqlite3_free().
+**
+** If an error occurs, leave an error code and message in the rbu handle
+** and return NULL.
+*/
+static RbuState *rbuLoadState(sqlite3rbu *p){
+  RbuState *pRet = 0;
+  sqlite3_stmt *pStmt = 0;
+  int rc;
+  int rc2;
+
+  pRet = (RbuState*)rbuMalloc(p, sizeof(RbuState));
+  if( pRet==0 ) return 0;
+
+  rc = prepareFreeAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
+      sqlite3_mprintf("SELECT k, v FROM %s.rbu_state", p->zStateDb)
+  );
+  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+    switch( sqlite3_column_int(pStmt, 0) ){
+      case RBU_STATE_STAGE:
+        pRet->eStage = sqlite3_column_int(pStmt, 1);
+        if( pRet->eStage!=RBU_STAGE_OAL
+         && pRet->eStage!=RBU_STAGE_MOVE
+         && pRet->eStage!=RBU_STAGE_CKPT
+        ){
+          p->rc = SQLITE_CORRUPT;
+        }
+        break;
+
+      case RBU_STATE_TBL:
+        pRet->zTbl = rbuStrndup((char*)sqlite3_column_text(pStmt, 1), &rc);
+        break;
+
+      case RBU_STATE_IDX:
+        pRet->zIdx = rbuStrndup((char*)sqlite3_column_text(pStmt, 1), &rc);
+        break;
+
+      case RBU_STATE_ROW:
+        pRet->nRow = sqlite3_column_int(pStmt, 1);
+        break;
+
+      case RBU_STATE_PROGRESS:
+        pRet->nProgress = sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_CKPT:
+        pRet->iWalCksum = sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_COOKIE:
+        pRet->iCookie = (u32)sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_OALSZ:
+        pRet->iOalSz = sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_PHASEONESTEP:
+        pRet->nPhaseOneStep = sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_DATATBL:
+        pRet->zDataTbl = rbuStrndup((char*)sqlite3_column_text(pStmt, 1), &rc);
+        break;
+
+      default:
+        rc = SQLITE_CORRUPT;
+        break;
+    }
+  }
+  rc2 = sqlite3_finalize(pStmt);
+  if( rc==SQLITE_OK ) rc = rc2;
+
+  p->rc = rc;
+  return pRet;
+}
+
+
+/*
+** Open the database handle and attach the RBU database as "rbu". If an
+** error occurs, leave an error code and message in the RBU handle.
+**
+** If argument dbMain is not NULL, then it is a database handle already
+** open on the target database. Use this handle instead of opening a new
+** one.
+*/
+static void rbuOpenDatabase(sqlite3rbu *p, sqlite3 *dbMain, int *pbRetry){
+  assert( p->rc || (p->dbMain==0 && p->dbRbu==0) );
+  assert( p->rc || rbuIsVacuum(p) || p->zTarget!=0 );
+  assert( dbMain==0 || rbuIsVacuum(p)==0 );
+
+  /* Open the RBU database */
+  p->dbRbu = rbuOpenDbhandle(p, p->zRbu, 1);
+  p->dbMain = dbMain;
+
+  if( p->rc==SQLITE_OK && rbuIsVacuum(p) ){
+    sqlite3_file_control(p->dbRbu, "main", SQLITE_FCNTL_RBUCNT, (void*)p);
+    if( p->zState==0 ){
+      const char *zFile = sqlite3_db_filename(p->dbRbu, "main");
+      p->zState = rbuMPrintf(p, "file:///%s-vacuum?modeof=%s", zFile, zFile);
+    }
+  }
+
+  /* If using separate RBU and state databases, attach the state database to
+  ** the RBU db handle now.  */
+  if( p->zState ){
+    rbuMPrintfExec(p, p->dbRbu, "ATTACH %Q AS stat", p->zState);
+    memcpy(p->zStateDb, "stat", 4);
+  }else{
+    memcpy(p->zStateDb, "main", 4);
+  }
+
+#if 0
+  if( p->rc==SQLITE_OK && rbuIsVacuum(p) ){
+    p->rc = sqlite3_exec(p->dbRbu, "BEGIN", 0, 0, 0);
+  }
+#endif
+
+  /* If it has not already been created, create the rbu_state table */
+  rbuMPrintfExec(p, p->dbRbu, RBU_CREATE_STATE, p->zStateDb);
+
+#if 0
+  if( rbuIsVacuum(p) ){
+    if( p->rc==SQLITE_OK ){
+      int rc2;
+      int bOk = 0;
+      sqlite3_stmt *pCnt = 0;
+      p->rc = prepareAndCollectError(p->dbRbu, &pCnt, &p->zErrmsg,
+          "SELECT count(*) FROM stat.sqlite_schema"
+      );
+      if( p->rc==SQLITE_OK
+       && sqlite3_step(pCnt)==SQLITE_ROW
+       && 1==sqlite3_column_int(pCnt, 0)
+      ){
+        bOk = 1;
+      }
+      rc2 = sqlite3_finalize(pCnt);
+      if( p->rc==SQLITE_OK ) p->rc = rc2;
+
+      if( p->rc==SQLITE_OK && bOk==0 ){
+        p->rc = SQLITE_ERROR;
+        p->zErrmsg = sqlite3_mprintf("invalid state database");
+      }
+
+      if( p->rc==SQLITE_OK ){
+        p->rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, 0);
+      }
+    }
+  }
+#endif
+
+  if( p->rc==SQLITE_OK && rbuIsVacuum(p) ){
+    int bOpen = 0;
+    int rc;
+    p->nRbu = 0;
+    p->pRbuFd = 0;
+    rc = sqlite3_file_control(p->dbRbu, "main", SQLITE_FCNTL_RBUCNT, (void*)p);
+    if( rc!=SQLITE_NOTFOUND ) p->rc = rc;
+    if( p->eStage>=RBU_STAGE_MOVE ){
+      bOpen = 1;
+    }else{
+      RbuState *pState = rbuLoadState(p);
+      if( pState ){
+        bOpen = (pState->eStage>=RBU_STAGE_MOVE);
+        rbuFreeState(pState);
+      }
+    }
+    if( bOpen ) p->dbMain = rbuOpenDbhandle(p, p->zRbu, p->nRbu<=1);
+  }
+
+  p->eStage = 0;
+  if( p->rc==SQLITE_OK && p->dbMain==0 ){
+    if( !rbuIsVacuum(p) ){
+      p->dbMain = rbuOpenDbhandle(p, p->zTarget, 1);
+    }else if( p->pRbuFd->pWalFd ){
+      if( pbRetry ){
+        p->pRbuFd->bNolock = 0;
+        sqlite3_close(p->dbRbu);
+        sqlite3_close(p->dbMain);
+        p->dbMain = 0;
+        p->dbRbu = 0;
+        *pbRetry = 1;
+        return;
+      }
+      p->rc = SQLITE_ERROR;
+      p->zErrmsg = sqlite3_mprintf("cannot vacuum wal mode database");
+    }else{
+      char *zTarget;
+      char *zExtra = 0;
+      if( strlen(p->zRbu)>=5 && 0==memcmp("file:", p->zRbu, 5) ){
+        zExtra = &p->zRbu[5];
+        while( *zExtra ){
+          if( *zExtra++=='?' ) break;
+        }
+        if( *zExtra=='\0' ) zExtra = 0;
+      }
+
+      zTarget = sqlite3_mprintf("file:%s-vactmp?rbu_memory=1%s%s",
+          sqlite3_db_filename(p->dbRbu, "main"),
+          (zExtra==0 ? "" : "&"), (zExtra==0 ? "" : zExtra)
+      );
+
+      if( zTarget==0 ){
+        p->rc = SQLITE_NOMEM;
+        return;
+      }
+      p->dbMain = rbuOpenDbhandle(p, zTarget, p->nRbu<=1);
+      sqlite3_free(zTarget);
+    }
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_create_function(p->dbMain,
+        "rbu_tmp_insert", -1, SQLITE_UTF8, (void*)p, rbuTmpInsertFunc, 0, 0
+    );
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_create_function(p->dbMain,
+        "rbu_fossil_delta", 2, SQLITE_UTF8, 0, rbuFossilDeltaFunc, 0, 0
+    );
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_create_function(p->dbRbu,
+        "rbu_target_name", -1, SQLITE_UTF8, (void*)p, rbuTargetNameFunc, 0, 0
+    );
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_file_control(p->dbMain, "main", SQLITE_FCNTL_RBU, (void*)p);
+  }
+  rbuMPrintfExec(p, p->dbMain, "SELECT * FROM sqlite_schema");
+
+  /* Mark the database file just opened as an RBU target database. If
+  ** this call returns SQLITE_NOTFOUND, then the RBU vfs is not in use.
+  ** This is an error.  */
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_file_control(p->dbMain, "main", SQLITE_FCNTL_RBU, (void*)p);
+  }
+
+  if( p->rc==SQLITE_NOTFOUND ){
+    p->rc = SQLITE_ERROR;
+    p->zErrmsg = sqlite3_mprintf("rbu vfs not found");
+  }
+}
+
+/*
+** This routine is a copy of the sqlite3FileSuffix3() routine from the core.
+** It is a no-op unless SQLITE_ENABLE_8_3_NAMES is defined.
+**
+** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
+** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
+** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
+** three characters, then shorten the suffix on z[] to be the last three
+** characters of the original suffix.
+**
+** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
+** do the suffix shortening regardless of URI parameter.
+**
+** Examples:
+**
+**     test.db-journal    =>   test.nal
+**     test.db-wal        =>   test.wal
+**     test.db-shm        =>   test.shm
+**     test.db-mj7f3319fa =>   test.9fa
+*/
+static void rbuFileSuffix3(const char *zBase, char *z){
+#ifdef SQLITE_ENABLE_8_3_NAMES
+#if SQLITE_ENABLE_8_3_NAMES<2
+  if( sqlite3_uri_boolean(zBase, "8_3_names", 0) )
+#endif
+  {
+    int i, sz;
+    sz = (int)strlen(z)&0xffffff;
+    for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
+    if( z[i]=='.' && sz>i+4 ) memmove(&z[i+1], &z[sz-3], 4);
+  }
+#else
+  UNUSED_PARAMETER2(zBase,z);
+#endif
+}
+
+/*
+** Return the current wal-index header checksum for the target database
+** as a 64-bit integer.
+**
+** The checksum is store in the first page of xShmMap memory as an 8-byte
+** blob starting at byte offset 40.
+*/
+static i64 rbuShmChecksum(sqlite3rbu *p){
+  i64 iRet = 0;
+  if( p->rc==SQLITE_OK ){
+    sqlite3_file *pDb = p->pTargetFd->pReal;
+    u32 volatile *ptr;
+    p->rc = pDb->pMethods->xShmMap(pDb, 0, 32*1024, 0, (void volatile**)&ptr);
+    if( p->rc==SQLITE_OK ){
+      iRet = (i64)(((u64)ptr[10] << 32) + ptr[11]);
+    }
+  }
+  return iRet;
+}
+
+/*
+** This function is called as part of initializing or reinitializing an
+** incremental checkpoint.
+**
+** It populates the sqlite3rbu.aFrame[] array with the set of
+** (wal frame -> db page) copy operations required to checkpoint the
+** current wal file, and obtains the set of shm locks required to safely
+** perform the copy operations directly on the file-system.
+**
+** If argument pState is not NULL, then the incremental checkpoint is
+** being resumed. In this case, if the checksum of the wal-index-header
+** following recovery is not the same as the checksum saved in the RbuState
+** object, then the rbu handle is set to DONE state. This occurs if some
+** other client appends a transaction to the wal file in the middle of
+** an incremental checkpoint.
+*/
+static void rbuSetupCheckpoint(sqlite3rbu *p, RbuState *pState){
+
+  /* If pState is NULL, then the wal file may not have been opened and
+  ** recovered. Running a read-statement here to ensure that doing so
+  ** does not interfere with the "capture" process below.  */
+  if( pState==0 ){
+    p->eStage = 0;
+    if( p->rc==SQLITE_OK ){
+      p->rc = sqlite3_exec(p->dbMain, "SELECT * FROM sqlite_schema", 0, 0, 0);
+    }
+  }
+
+  /* Assuming no error has occurred, run a "restart" checkpoint with the
+  ** sqlite3rbu.eStage variable set to CAPTURE. This turns on the following
+  ** special behaviour in the rbu VFS:
+  **
+  **   * If the exclusive shm WRITER or READ0 lock cannot be obtained,
+  **     the checkpoint fails with SQLITE_BUSY (normally SQLite would
+  **     proceed with running a passive checkpoint instead of failing).
+  **
+  **   * Attempts to read from the *-wal file or write to the database file
+  **     do not perform any IO. Instead, the frame/page combinations that
+  **     would be read/written are recorded in the sqlite3rbu.aFrame[]
+  **     array.
+  **
+  **   * Calls to xShmLock(UNLOCK) to release the exclusive shm WRITER,
+  **     READ0 and CHECKPOINT locks taken as part of the checkpoint are
+  **     no-ops. These locks will not be released until the connection
+  **     is closed.
+  **
+  **   * Attempting to xSync() the database file causes an SQLITE_NOTICE
+  **     error.
+  **
+  ** As a result, unless an error (i.e. OOM or SQLITE_BUSY) occurs, the
+  ** checkpoint below fails with SQLITE_NOTICE, and leaves the aFrame[]
+  ** array populated with a set of (frame -> page) mappings. Because the
+  ** WRITER, CHECKPOINT and READ0 locks are still held, it is safe to copy
+  ** data from the wal file into the database file according to the
+  ** contents of aFrame[].
+  */
+  if( p->rc==SQLITE_OK ){
+    int rc2;
+    p->eStage = RBU_STAGE_CAPTURE;
+    rc2 = sqlite3_exec(p->dbMain, "PRAGMA main.wal_checkpoint=restart", 0, 0,0);
+    if( rc2!=SQLITE_NOTICE ) p->rc = rc2;
+  }
+
+  if( p->rc==SQLITE_OK && p->nFrame>0 ){
+    p->eStage = RBU_STAGE_CKPT;
+    p->nStep = (pState ? pState->nRow : 0);
+    p->aBuf = rbuMalloc(p, p->pgsz);
+    p->iWalCksum = rbuShmChecksum(p);
+  }
+
+  if( p->rc==SQLITE_OK ){
+    if( p->nFrame==0 || (pState && pState->iWalCksum!=p->iWalCksum) ){
+      p->rc = SQLITE_DONE;
+      p->eStage = RBU_STAGE_DONE;
+    }else{
+      int nSectorSize;
+      sqlite3_file *pDb = p->pTargetFd->pReal;
+      sqlite3_file *pWal = p->pTargetFd->pWalFd->pReal;
+      assert( p->nPagePerSector==0 );
+      nSectorSize = pDb->pMethods->xSectorSize(pDb);
+      if( nSectorSize>p->pgsz ){
+        p->nPagePerSector = nSectorSize / p->pgsz;
+      }else{
+        p->nPagePerSector = 1;
+      }
+
+      /* Call xSync() on the wal file. This causes SQLite to sync the
+      ** directory in which the target database and the wal file reside, in
+      ** case it has not been synced since the rename() call in
+      ** rbuMoveOalFile(). */
+      p->rc = pWal->pMethods->xSync(pWal, SQLITE_SYNC_NORMAL);
+    }
+  }
+}
+
+/*
+** Called when iAmt bytes are read from offset iOff of the wal file while
+** the rbu object is in capture mode. Record the frame number of the frame
+** being read in the aFrame[] array.
+*/
+static int rbuCaptureWalRead(sqlite3rbu *pRbu, i64 iOff, int iAmt){
+  const u32 mReq = (1<<WAL_LOCK_WRITE)|(1<<WAL_LOCK_CKPT)|(1<<WAL_LOCK_READ0);
+  u32 iFrame;
+
+  if( pRbu->mLock!=mReq ){
+    pRbu->rc = SQLITE_BUSY;
+    return SQLITE_NOTICE_RBU;
+  }
+
+  pRbu->pgsz = iAmt;
+  if( pRbu->nFrame==pRbu->nFrameAlloc ){
+    int nNew = (pRbu->nFrameAlloc ? pRbu->nFrameAlloc : 64) * 2;
+    RbuFrame *aNew;
+    aNew = (RbuFrame*)sqlite3_realloc64(pRbu->aFrame, nNew * sizeof(RbuFrame));
+    if( aNew==0 ) return SQLITE_NOMEM;
+    pRbu->aFrame = aNew;
+    pRbu->nFrameAlloc = nNew;
+  }
+
+  iFrame = (u32)((iOff-32) / (i64)(iAmt+24)) + 1;
+  if( pRbu->iMaxFrame<iFrame ) pRbu->iMaxFrame = iFrame;
+  pRbu->aFrame[pRbu->nFrame].iWalFrame = iFrame;
+  pRbu->aFrame[pRbu->nFrame].iDbPage = 0;
+  pRbu->nFrame++;
+  return SQLITE_OK;
+}
+
+/*
+** Called when a page of data is written to offset iOff of the database
+** file while the rbu handle is in capture mode. Record the page number
+** of the page being written in the aFrame[] array.
+*/
+static int rbuCaptureDbWrite(sqlite3rbu *pRbu, i64 iOff){
+  pRbu->aFrame[pRbu->nFrame-1].iDbPage = (u32)(iOff / pRbu->pgsz) + 1;
+  return SQLITE_OK;
+}
+
+/*
+** This is called as part of an incremental checkpoint operation. Copy
+** a single frame of data from the wal file into the database file, as
+** indicated by the RbuFrame object.
+*/
+static void rbuCheckpointFrame(sqlite3rbu *p, RbuFrame *pFrame){
+  sqlite3_file *pWal = p->pTargetFd->pWalFd->pReal;
+  sqlite3_file *pDb = p->pTargetFd->pReal;
+  i64 iOff;
+
+  assert( p->rc==SQLITE_OK );
+  iOff = (i64)(pFrame->iWalFrame-1) * (p->pgsz + 24) + 32 + 24;
+  p->rc = pWal->pMethods->xRead(pWal, p->aBuf, p->pgsz, iOff);
+  if( p->rc ) return;
+
+  iOff = (i64)(pFrame->iDbPage-1) * p->pgsz;
+  p->rc = pDb->pMethods->xWrite(pDb, p->aBuf, p->pgsz, iOff);
+}
+
+/*
+** This value is copied from the definition of ZIPVFS_CTRL_FILE_POINTER
+** in zipvfs.h.
+*/
+#define RBU_ZIPVFS_CTRL_FILE_POINTER 230439
+
+/*
+** Take an EXCLUSIVE lock on the database file. Return SQLITE_OK if
+** successful, or an SQLite error code otherwise.
+*/
+static int rbuLockDatabase(sqlite3 *db){
+  int rc = SQLITE_OK;
+  sqlite3_file *fd = 0;
+
+  sqlite3_file_control(db, "main", RBU_ZIPVFS_CTRL_FILE_POINTER, &fd);
+  if( fd ){
+    sqlite3_file_control(db, "main", SQLITE_FCNTL_FILE_POINTER, &fd);
+    rc = fd->pMethods->xLock(fd, SQLITE_LOCK_SHARED);
+    if( rc==SQLITE_OK ){
+      rc = fd->pMethods->xUnlock(fd, SQLITE_LOCK_NONE);
+    }
+    sqlite3_file_control(db, "main", RBU_ZIPVFS_CTRL_FILE_POINTER, &fd);
+  }else{
+    sqlite3_file_control(db, "main", SQLITE_FCNTL_FILE_POINTER, &fd);
+  }
+
+  if( rc==SQLITE_OK && fd->pMethods ){
+    rc = fd->pMethods->xLock(fd, SQLITE_LOCK_SHARED);
+    if( rc==SQLITE_OK ){
+      rc = fd->pMethods->xLock(fd, SQLITE_LOCK_EXCLUSIVE);
+    }
+  }
+  return rc;
+}
+
+/*
+** Return true if the database handle passed as the only argument
+** was opened with the rbu_exclusive_checkpoint=1 URI parameter
+** specified. Or false otherwise.
+*/
+static int rbuExclusiveCheckpoint(sqlite3 *db){
+  const char *zUri = sqlite3_db_filename(db, 0);
+  return sqlite3_uri_boolean(zUri, RBU_EXCLUSIVE_CHECKPOINT, 0);
+}
+
+#if defined(_WIN32_WCE)
+static LPWSTR rbuWinUtf8ToUnicode(const char *zFilename){
+  int nChar;
+  LPWSTR zWideFilename;
+
+  nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0);
+  if( nChar==0 ){
+    return 0;
+  }
+  zWideFilename = sqlite3_malloc64( nChar*sizeof(zWideFilename[0]) );
+  if( zWideFilename==0 ){
+    return 0;
+  }
+  memset(zWideFilename, 0, nChar*sizeof(zWideFilename[0]));
+  nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, zWideFilename,
+                                nChar);
+  if( nChar==0 ){
+    sqlite3_free(zWideFilename);
+    zWideFilename = 0;
+  }
+  return zWideFilename;
+}
+#endif
+
+/*
+** The RBU handle is currently in RBU_STAGE_OAL state, with a SHARED lock
+** on the database file. This proc moves the *-oal file to the *-wal path,
+** then reopens the database file (this time in vanilla, non-oal, WAL mode).
+** If an error occurs, leave an error code and error message in the rbu
+** handle.
+*/
+static void rbuMoveOalFile(sqlite3rbu *p){
+  const char *zBase = sqlite3_db_filename(p->dbMain, "main");
+  const char *zMove = zBase;
+  char *zOal;
+  char *zWal;
+
+  if( rbuIsVacuum(p) ){
+    zMove = sqlite3_db_filename(p->dbRbu, "main");
+  }
+  zOal = sqlite3_mprintf("%s-oal", zMove);
+  zWal = sqlite3_mprintf("%s-wal", zMove);
+
+  assert( p->eStage==RBU_STAGE_MOVE );
+  assert( p->rc==SQLITE_OK && p->zErrmsg==0 );
+  if( zWal==0 || zOal==0 ){
+    p->rc = SQLITE_NOMEM;
+  }else{
+    /* Move the *-oal file to *-wal. At this point connection p->db is
+    ** holding a SHARED lock on the target database file (because it is
+    ** in WAL mode). So no other connection may be writing the db.
+    **
+    ** In order to ensure that there are no database readers, an EXCLUSIVE
+    ** lock is obtained here before the *-oal is moved to *-wal.
+    */
+    sqlite3 *dbMain = 0;
+    rbuFileSuffix3(zBase, zWal);
+    rbuFileSuffix3(zBase, zOal);
+
+    /* Re-open the databases. */
+    rbuObjIterFinalize(&p->objiter);
+    sqlite3_close(p->dbRbu);
+    sqlite3_close(p->dbMain);
+    p->dbMain = 0;
+    p->dbRbu = 0;
+
+    dbMain = rbuOpenDbhandle(p, p->zTarget, 1);
+    if( dbMain ){
+      assert( p->rc==SQLITE_OK );
+      p->rc = rbuLockDatabase(dbMain);
+    }
+
+    if( p->rc==SQLITE_OK ){
+      p->rc = p->xRename(p->pRenameArg, zOal, zWal);
+    }
+
+    if( p->rc!=SQLITE_OK
+     || rbuIsVacuum(p)
+     || rbuExclusiveCheckpoint(dbMain)==0
+    ){
+      sqlite3_close(dbMain);
+      dbMain = 0;
+    }
+
+    if( p->rc==SQLITE_OK ){
+      rbuOpenDatabase(p, dbMain, 0);
+      rbuSetupCheckpoint(p, 0);
+    }
+  }
+
+  sqlite3_free(zWal);
+  sqlite3_free(zOal);
+}
+
+/*
+** The SELECT statement iterating through the keys for the current object
+** (p->objiter.pSelect) currently points to a valid row. This function
+** determines the type of operation requested by this row and returns
+** one of the following values to indicate the result:
+**
+**     * RBU_INSERT
+**     * RBU_DELETE
+**     * RBU_IDX_DELETE
+**     * RBU_UPDATE
+**
+** If RBU_UPDATE is returned, then output variable *pzMask is set to
+** point to the text value indicating the columns to update.
+**
+** If the rbu_control field contains an invalid value, an error code and
+** message are left in the RBU handle and zero returned.
+*/
+static int rbuStepType(sqlite3rbu *p, const char **pzMask){
+  int iCol = p->objiter.nCol;     /* Index of rbu_control column */
+  int res = 0;                    /* Return value */
+
+  switch( sqlite3_column_type(p->objiter.pSelect, iCol) ){
+    case SQLITE_INTEGER: {
+      int iVal = sqlite3_column_int(p->objiter.pSelect, iCol);
+      switch( iVal ){
+        case 0: res = RBU_INSERT;     break;
+        case 1: res = RBU_DELETE;     break;
+        case 2: res = RBU_REPLACE;    break;
+        case 3: res = RBU_IDX_DELETE; break;
+        case 4: res = RBU_IDX_INSERT; break;
+      }
+      break;
+    }
+
+    case SQLITE_TEXT: {
+      const unsigned char *z = sqlite3_column_text(p->objiter.pSelect, iCol);
+      if( z==0 ){
+        p->rc = SQLITE_NOMEM;
+      }else{
+        *pzMask = (const char*)z;
+      }
+      res = RBU_UPDATE;
+
+      break;
+    }
+
+    default:
+      break;
+  }
+
+  if( res==0 ){
+    rbuBadControlError(p);
+  }
+  return res;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Assert that column iCol of statement pStmt is named zName.
+*/
+static void assertColumnName(sqlite3_stmt *pStmt, int iCol, const char *zName){
+  const char *zCol = sqlite3_column_name(pStmt, iCol);
+  assert( 0==sqlite3_stricmp(zName, zCol) );
+}
+#else
+# define assertColumnName(x,y,z)
+#endif
+
+/*
+** Argument eType must be one of RBU_INSERT, RBU_DELETE, RBU_IDX_INSERT or
+** RBU_IDX_DELETE. This function performs the work of a single
+** sqlite3rbu_step() call for the type of operation specified by eType.
+*/
+static void rbuStepOneOp(sqlite3rbu *p, int eType){
+  RbuObjIter *pIter = &p->objiter;
+  sqlite3_value *pVal;
+  sqlite3_stmt *pWriter;
+  int i;
+
+  assert( p->rc==SQLITE_OK );
+  assert( eType!=RBU_DELETE || pIter->zIdx==0 );
+  assert( eType==RBU_DELETE || eType==RBU_IDX_DELETE
+       || eType==RBU_INSERT || eType==RBU_IDX_INSERT
+  );
+
+  /* If this is a delete, decrement nPhaseOneStep by nIndex. If the DELETE
+  ** statement below does actually delete a row, nPhaseOneStep will be
+  ** incremented by the same amount when SQL function rbu_tmp_insert()
+  ** is invoked by the trigger.  */
+  if( eType==RBU_DELETE ){
+    p->nPhaseOneStep -= p->objiter.nIndex;
+  }
+
+  if( eType==RBU_IDX_DELETE || eType==RBU_DELETE ){
+    pWriter = pIter->pDelete;
+  }else{
+    pWriter = pIter->pInsert;
+  }
+
+  for(i=0; i<pIter->nCol; i++){
+    /* If this is an INSERT into a table b-tree and the table has an
+    ** explicit INTEGER PRIMARY KEY, check that this is not an attempt
+    ** to write a NULL into the IPK column. That is not permitted.  */
+    if( eType==RBU_INSERT
+     && pIter->zIdx==0 && pIter->eType==RBU_PK_IPK && pIter->abTblPk[i]
+     && sqlite3_column_type(pIter->pSelect, i)==SQLITE_NULL
+    ){
+      p->rc = SQLITE_MISMATCH;
+      p->zErrmsg = sqlite3_mprintf("datatype mismatch");
+      return;
+    }
+
+    if( eType==RBU_DELETE && pIter->abTblPk[i]==0 ){
+      continue;
+    }
+
+    pVal = sqlite3_column_value(pIter->pSelect, i);
+    p->rc = sqlite3_bind_value(pWriter, i+1, pVal);
+    if( p->rc ) return;
+  }
+  if( pIter->zIdx==0 ){
+    if( pIter->eType==RBU_PK_VTAB
+     || pIter->eType==RBU_PK_NONE
+     || (pIter->eType==RBU_PK_EXTERNAL && rbuIsVacuum(p))
+    ){
+      /* For a virtual table, or a table with no primary key, the
+      ** SELECT statement is:
+      **
+      **   SELECT <cols>, rbu_control, rbu_rowid FROM ....
+      **
+      ** Hence column_value(pIter->nCol+1).
+      */
+      assertColumnName(pIter->pSelect, pIter->nCol+1,
+          rbuIsVacuum(p) ? "rowid" : "rbu_rowid"
+      );
+      pVal = sqlite3_column_value(pIter->pSelect, pIter->nCol+1);
+      p->rc = sqlite3_bind_value(pWriter, pIter->nCol+1, pVal);
+    }
+  }
+  if( p->rc==SQLITE_OK ){
+    sqlite3_step(pWriter);
+    p->rc = resetAndCollectError(pWriter, &p->zErrmsg);
+  }
+}
+
+/*
+** This function does the work for an sqlite3rbu_step() call.
+**
+** The object-iterator (p->objiter) currently points to a valid object,
+** and the input cursor (p->objiter.pSelect) currently points to a valid
+** input row. Perform whatever processing is required and return.
+**
+** If no  error occurs, SQLITE_OK is returned. Otherwise, an error code
+** and message is left in the RBU handle and a copy of the error code
+** returned.
+*/
+static int rbuStep(sqlite3rbu *p){
+  RbuObjIter *pIter = &p->objiter;
+  const char *zMask = 0;
+  int eType = rbuStepType(p, &zMask);
+
+  if( eType ){
+    assert( eType==RBU_INSERT     || eType==RBU_DELETE
+         || eType==RBU_REPLACE    || eType==RBU_IDX_DELETE
+         || eType==RBU_IDX_INSERT || eType==RBU_UPDATE
+    );
+    assert( eType!=RBU_UPDATE || pIter->zIdx==0 );
+
+    if( pIter->zIdx==0 && (eType==RBU_IDX_DELETE || eType==RBU_IDX_INSERT) ){
+      rbuBadControlError(p);
+    }
+    else if( eType==RBU_REPLACE ){
+      if( pIter->zIdx==0 ){
+        p->nPhaseOneStep += p->objiter.nIndex;
+        rbuStepOneOp(p, RBU_DELETE);
+      }
+      if( p->rc==SQLITE_OK ) rbuStepOneOp(p, RBU_INSERT);
+    }
+    else if( eType!=RBU_UPDATE ){
+      rbuStepOneOp(p, eType);
+    }
+    else{
+      sqlite3_value *pVal;
+      sqlite3_stmt *pUpdate = 0;
+      assert( eType==RBU_UPDATE );
+      p->nPhaseOneStep -= p->objiter.nIndex;
+      rbuGetUpdateStmt(p, pIter, zMask, &pUpdate);
+      if( pUpdate ){
+        int i;
+        for(i=0; p->rc==SQLITE_OK && i<pIter->nCol; i++){
+          char c = zMask[pIter->aiSrcOrder[i]];
+          pVal = sqlite3_column_value(pIter->pSelect, i);
+          if( pIter->abTblPk[i] || c!='.' ){
+            p->rc = sqlite3_bind_value(pUpdate, i+1, pVal);
+          }
+        }
+        if( p->rc==SQLITE_OK
+         && (pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE)
+        ){
+          /* Bind the rbu_rowid value to column _rowid_ */
+          assertColumnName(pIter->pSelect, pIter->nCol+1, "rbu_rowid");
+          pVal = sqlite3_column_value(pIter->pSelect, pIter->nCol+1);
+          p->rc = sqlite3_bind_value(pUpdate, pIter->nCol+1, pVal);
+        }
+        if( p->rc==SQLITE_OK ){
+          sqlite3_step(pUpdate);
+          p->rc = resetAndCollectError(pUpdate, &p->zErrmsg);
+        }
+      }
+    }
+  }
+  return p->rc;
+}
+
+/*
+** Increment the schema cookie of the main database opened by p->dbMain.
+**
+** Or, if this is an RBU vacuum, set the schema cookie of the main db
+** opened by p->dbMain to one more than the schema cookie of the main
+** db opened by p->dbRbu.
+*/
+static void rbuIncrSchemaCookie(sqlite3rbu *p){
+  if( p->rc==SQLITE_OK ){
+    sqlite3 *dbread = (rbuIsVacuum(p) ? p->dbRbu : p->dbMain);
+    int iCookie = 1000000;
+    sqlite3_stmt *pStmt;
+
+    p->rc = prepareAndCollectError(dbread, &pStmt, &p->zErrmsg,
+        "PRAGMA schema_version"
+    );
+    if( p->rc==SQLITE_OK ){
+      /* Coverage: it may be that this sqlite3_step() cannot fail. There
+      ** is already a transaction open, so the prepared statement cannot
+      ** throw an SQLITE_SCHEMA exception. The only database page the
+      ** statement reads is page 1, which is guaranteed to be in the cache.
+      ** And no memory allocations are required.  */
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        iCookie = sqlite3_column_int(pStmt, 0);
+      }
+      rbuFinalize(p, pStmt);
+    }
+    if( p->rc==SQLITE_OK ){
+      rbuMPrintfExec(p, p->dbMain, "PRAGMA schema_version = %d", iCookie+1);
+    }
+  }
+}
+
+/*
+** Update the contents of the rbu_state table within the rbu database. The
+** value stored in the RBU_STATE_STAGE column is eStage. All other values
+** are determined by inspecting the rbu handle passed as the first argument.
+*/
+static void rbuSaveState(sqlite3rbu *p, int eStage){
+  if( p->rc==SQLITE_OK || p->rc==SQLITE_DONE ){
+    sqlite3_stmt *pInsert = 0;
+    rbu_file *pFd = (rbuIsVacuum(p) ? p->pRbuFd : p->pTargetFd);
+    int rc;
+
+    assert( p->zErrmsg==0 );
+    rc = prepareFreeAndCollectError(p->dbRbu, &pInsert, &p->zErrmsg,
+        sqlite3_mprintf(
+          "INSERT OR REPLACE INTO %s.rbu_state(k, v) VALUES "
+          "(%d, %d), "
+          "(%d, %Q), "
+          "(%d, %Q), "
+          "(%d, %d), "
+          "(%d, %lld), "
+          "(%d, %lld), "
+          "(%d, %lld), "
+          "(%d, %lld), "
+          "(%d, %lld), "
+          "(%d, %Q)  ",
+          p->zStateDb,
+          RBU_STATE_STAGE, eStage,
+          RBU_STATE_TBL, p->objiter.zTbl,
+          RBU_STATE_IDX, p->objiter.zIdx,
+          RBU_STATE_ROW, p->nStep,
+          RBU_STATE_PROGRESS, p->nProgress,
+          RBU_STATE_CKPT, p->iWalCksum,
+          RBU_STATE_COOKIE, (i64)pFd->iCookie,
+          RBU_STATE_OALSZ, p->iOalSz,
+          RBU_STATE_PHASEONESTEP, p->nPhaseOneStep,
+          RBU_STATE_DATATBL, p->objiter.zDataTbl
+      )
+    );
+    assert( pInsert==0 || rc==SQLITE_OK );
+
+    if( rc==SQLITE_OK ){
+      sqlite3_step(pInsert);
+      rc = sqlite3_finalize(pInsert);
+    }
+    if( rc!=SQLITE_OK ) p->rc = rc;
+  }
+}
+
+
+/*
+** The second argument passed to this function is the name of a PRAGMA
+** setting - "page_size", "auto_vacuum", "user_version" or "application_id".
+** This function executes the following on sqlite3rbu.dbRbu:
+**
+**   "PRAGMA main.$zPragma"
+**
+** where $zPragma is the string passed as the second argument, then
+** on sqlite3rbu.dbMain:
+**
+**   "PRAGMA main.$zPragma = $val"
+**
+** where $val is the value returned by the first PRAGMA invocation.
+**
+** In short, it copies the value  of the specified PRAGMA setting from
+** dbRbu to dbMain.
+*/
+static void rbuCopyPragma(sqlite3rbu *p, const char *zPragma){
+  if( p->rc==SQLITE_OK ){
+    sqlite3_stmt *pPragma = 0;
+    p->rc = prepareFreeAndCollectError(p->dbRbu, &pPragma, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.%s", zPragma)
+    );
+    if( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pPragma) ){
+      p->rc = rbuMPrintfExec(p, p->dbMain, "PRAGMA main.%s = %d",
+          zPragma, sqlite3_column_int(pPragma, 0)
+      );
+    }
+    rbuFinalize(p, pPragma);
+  }
+}
+
+/*
+** The RBU handle passed as the only argument has just been opened and
+** the state database is empty. If this RBU handle was opened for an
+** RBU vacuum operation, create the schema in the target db.
+*/
+static void rbuCreateTargetSchema(sqlite3rbu *p){
+  sqlite3_stmt *pSql = 0;
+  sqlite3_stmt *pInsert = 0;
+
+  assert( rbuIsVacuum(p) );
+  p->rc = sqlite3_exec(p->dbMain, "PRAGMA writable_schema=1", 0,0, &p->zErrmsg);
+  if( p->rc==SQLITE_OK ){
+    p->rc = prepareAndCollectError(p->dbRbu, &pSql, &p->zErrmsg,
+      "SELECT sql FROM sqlite_schema WHERE sql!='' AND rootpage!=0"
+      " AND name!='sqlite_sequence' "
+      " ORDER BY type DESC"
+    );
+  }
+
+  while( p->rc==SQLITE_OK && sqlite3_step(pSql)==SQLITE_ROW ){
+    const char *zSql = (const char*)sqlite3_column_text(pSql, 0);
+    p->rc = sqlite3_exec(p->dbMain, zSql, 0, 0, &p->zErrmsg);
+  }
+  rbuFinalize(p, pSql);
+  if( p->rc!=SQLITE_OK ) return;
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = prepareAndCollectError(p->dbRbu, &pSql, &p->zErrmsg,
+        "SELECT * FROM sqlite_schema WHERE rootpage=0 OR rootpage IS NULL"
+    );
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = prepareAndCollectError(p->dbMain, &pInsert, &p->zErrmsg,
+        "INSERT INTO sqlite_schema VALUES(?,?,?,?,?)"
+    );
+  }
+
+  while( p->rc==SQLITE_OK && sqlite3_step(pSql)==SQLITE_ROW ){
+    int i;
+    for(i=0; i<5; i++){
+      sqlite3_bind_value(pInsert, i+1, sqlite3_column_value(pSql, i));
+    }
+    sqlite3_step(pInsert);
+    p->rc = sqlite3_reset(pInsert);
+  }
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_exec(p->dbMain, "PRAGMA writable_schema=0",0,0,&p->zErrmsg);
+  }
+
+  rbuFinalize(p, pSql);
+  rbuFinalize(p, pInsert);
+}
+
+/*
+** Step the RBU object.
+*/
+SQLITE_API int sqlite3rbu_step(sqlite3rbu *p){
+  if( p ){
+    switch( p->eStage ){
+      case RBU_STAGE_OAL: {
+        RbuObjIter *pIter = &p->objiter;
+
+        /* If this is an RBU vacuum operation and the state table was empty
+        ** when this handle was opened, create the target database schema. */
+        if( rbuIsVacuum(p) && p->nProgress==0 && p->rc==SQLITE_OK ){
+          rbuCreateTargetSchema(p);
+          rbuCopyPragma(p, "user_version");
+          rbuCopyPragma(p, "application_id");
+        }
+
+        while( p->rc==SQLITE_OK && pIter->zTbl ){
+
+          if( pIter->bCleanup ){
+            /* Clean up the rbu_tmp_xxx table for the previous table. It
+            ** cannot be dropped as there are currently active SQL statements.
+            ** But the contents can be deleted.  */
+            if( rbuIsVacuum(p)==0 && pIter->abIndexed ){
+              rbuMPrintfExec(p, p->dbRbu,
+                  "DELETE FROM %s.'rbu_tmp_%q'", p->zStateDb, pIter->zDataTbl
+              );
+            }
+          }else{
+            rbuObjIterPrepareAll(p, pIter, 0);
+
+            /* Advance to the next row to process. */
+            if( p->rc==SQLITE_OK ){
+              int rc = sqlite3_step(pIter->pSelect);
+              if( rc==SQLITE_ROW ){
+                p->nProgress++;
+                p->nStep++;
+                return rbuStep(p);
+              }
+              p->rc = sqlite3_reset(pIter->pSelect);
+              p->nStep = 0;
+            }
+          }
+
+          rbuObjIterNext(p, pIter);
+        }
+
+        if( p->rc==SQLITE_OK ){
+          assert( pIter->zTbl==0 );
+          rbuSaveState(p, RBU_STAGE_MOVE);
+          rbuIncrSchemaCookie(p);
+          if( p->rc==SQLITE_OK ){
+            p->rc = sqlite3_exec(p->dbMain, "COMMIT", 0, 0, &p->zErrmsg);
+          }
+          if( p->rc==SQLITE_OK ){
+            p->rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, &p->zErrmsg);
+          }
+          p->eStage = RBU_STAGE_MOVE;
+        }
+        break;
+      }
+
+      case RBU_STAGE_MOVE: {
+        if( p->rc==SQLITE_OK ){
+          rbuMoveOalFile(p);
+          p->nProgress++;
+        }
+        break;
+      }
+
+      case RBU_STAGE_CKPT: {
+        if( p->rc==SQLITE_OK ){
+          if( p->nStep>=p->nFrame ){
+            sqlite3_file *pDb = p->pTargetFd->pReal;
+
+            /* Sync the db file */
+            p->rc = pDb->pMethods->xSync(pDb, SQLITE_SYNC_NORMAL);
+
+            /* Update nBackfill */
+            if( p->rc==SQLITE_OK ){
+              void volatile *ptr;
+              p->rc = pDb->pMethods->xShmMap(pDb, 0, 32*1024, 0, &ptr);
+              if( p->rc==SQLITE_OK ){
+                ((u32 volatile*)ptr)[24] = p->iMaxFrame;
+              }
+            }
+
+            if( p->rc==SQLITE_OK ){
+              p->eStage = RBU_STAGE_DONE;
+              p->rc = SQLITE_DONE;
+            }
+          }else{
+            /* At one point the following block copied a single frame from the
+            ** wal file to the database file. So that one call to sqlite3rbu_step()
+            ** checkpointed a single frame.
+            **
+            ** However, if the sector-size is larger than the page-size, and the
+            ** application calls sqlite3rbu_savestate() or close() immediately
+            ** after this step, then rbu_step() again, then a power failure occurs,
+            ** then the database page written here may be damaged. Work around
+            ** this by checkpointing frames until the next page in the aFrame[]
+            ** lies on a different disk sector to the current one. */
+            u32 iSector;
+            do{
+              RbuFrame *pFrame = &p->aFrame[p->nStep];
+              iSector = (pFrame->iDbPage-1) / p->nPagePerSector;
+              rbuCheckpointFrame(p, pFrame);
+              p->nStep++;
+            }while( p->nStep<p->nFrame
+                 && iSector==((p->aFrame[p->nStep].iDbPage-1) / p->nPagePerSector)
+                 && p->rc==SQLITE_OK
+            );
+          }
+          p->nProgress++;
+        }
+        break;
+      }
+
+      default:
+        break;
+    }
+    return p->rc;
+  }else{
+    return SQLITE_NOMEM;
+  }
+}
+
+/*
+** Compare strings z1 and z2, returning 0 if they are identical, or non-zero
+** otherwise. Either or both argument may be NULL. Two NULL values are
+** considered equal, and NULL is considered distinct from all other values.
+*/
+static int rbuStrCompare(const char *z1, const char *z2){
+  if( z1==0 && z2==0 ) return 0;
+  if( z1==0 || z2==0 ) return 1;
+  return (sqlite3_stricmp(z1, z2)!=0);
+}
+
+/*
+** This function is called as part of sqlite3rbu_open() when initializing
+** an rbu handle in OAL stage. If the rbu update has not started (i.e.
+** the rbu_state table was empty) it is a no-op. Otherwise, it arranges
+** things so that the next call to sqlite3rbu_step() continues on from
+** where the previous rbu handle left off.
+**
+** If an error occurs, an error code and error message are left in the
+** rbu handle passed as the first argument.
+*/
+static void rbuSetupOal(sqlite3rbu *p, RbuState *pState){
+  assert( p->rc==SQLITE_OK );
+  if( pState->zTbl ){
+    RbuObjIter *pIter = &p->objiter;
+    int rc = SQLITE_OK;
+
+    while( rc==SQLITE_OK && pIter->zTbl && (pIter->bCleanup
+       || rbuStrCompare(pIter->zIdx, pState->zIdx)
+       || (pState->zDataTbl==0 && rbuStrCompare(pIter->zTbl, pState->zTbl))
+       || (pState->zDataTbl && rbuStrCompare(pIter->zDataTbl, pState->zDataTbl))
+    )){
+      rc = rbuObjIterNext(p, pIter);
+    }
+
+    if( rc==SQLITE_OK && !pIter->zTbl ){
+      rc = SQLITE_ERROR;
+      p->zErrmsg = sqlite3_mprintf("rbu_state mismatch error");
+    }
+
+    if( rc==SQLITE_OK ){
+      p->nStep = pState->nRow;
+      rc = rbuObjIterPrepareAll(p, &p->objiter, p->nStep);
+    }
+
+    p->rc = rc;
+  }
+}
+
+/*
+** If there is a "*-oal" file in the file-system corresponding to the
+** target database in the file-system, delete it. If an error occurs,
+** leave an error code and error message in the rbu handle.
+*/
+static void rbuDeleteOalFile(sqlite3rbu *p){
+  char *zOal = rbuMPrintf(p, "%s-oal", p->zTarget);
+  if( zOal ){
+    sqlite3_vfs *pVfs = 0;
+    sqlite3_file_control(p->dbMain, "main", SQLITE_FCNTL_VFS_POINTER, &pVfs);
+    assert( pVfs && p->rc==SQLITE_OK && p->zErrmsg==0 );
+    pVfs->xDelete(pVfs, zOal, 0);
+    sqlite3_free(zOal);
+  }
+}
+
+/*
+** Allocate a private rbu VFS for the rbu handle passed as the only
+** argument. This VFS will be used unless the call to sqlite3rbu_open()
+** specified a URI with a vfs=? option in place of a target database
+** file name.
+*/
+static void rbuCreateVfs(sqlite3rbu *p){
+  int rnd;
+  char zRnd[64];
+
+  assert( p->rc==SQLITE_OK );
+  sqlite3_randomness(sizeof(int), (void*)&rnd);
+  sqlite3_snprintf(sizeof(zRnd), zRnd, "rbu_vfs_%d", rnd);
+  p->rc = sqlite3rbu_create_vfs(zRnd, 0);
+  if( p->rc==SQLITE_OK ){
+    sqlite3_vfs *pVfs = sqlite3_vfs_find(zRnd);
+    assert( pVfs );
+    p->zVfsName = pVfs->zName;
+    ((rbu_vfs*)pVfs)->pRbu = p;
+  }
+}
+
+/*
+** Destroy the private VFS created for the rbu handle passed as the only
+** argument by an earlier call to rbuCreateVfs().
+*/
+static void rbuDeleteVfs(sqlite3rbu *p){
+  if( p->zVfsName ){
+    sqlite3rbu_destroy_vfs(p->zVfsName);
+    p->zVfsName = 0;
+  }
+}
+
+/*
+** This user-defined SQL function is invoked with a single argument - the
+** name of a table expected to appear in the target database. It returns
+** the number of auxilliary indexes on the table.
+*/
+static void rbuIndexCntFunc(
+  sqlite3_context *pCtx,
+  int nVal,
+  sqlite3_value **apVal
+){
+  sqlite3rbu *p = (sqlite3rbu*)sqlite3_user_data(pCtx);
+  sqlite3_stmt *pStmt = 0;
+  char *zErrmsg = 0;
+  int rc;
+  sqlite3 *db = (rbuIsVacuum(p) ? p->dbRbu : p->dbMain);
+
+  assert( nVal==1 );
+  UNUSED_PARAMETER(nVal);
+
+  rc = prepareFreeAndCollectError(db, &pStmt, &zErrmsg,
+      sqlite3_mprintf("SELECT count(*) FROM sqlite_schema "
+        "WHERE type='index' AND tbl_name = %Q", sqlite3_value_text(apVal[0]))
+  );
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error(pCtx, zErrmsg, -1);
+  }else{
+    int nIndex = 0;
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      nIndex = sqlite3_column_int(pStmt, 0);
+    }
+    rc = sqlite3_finalize(pStmt);
+    if( rc==SQLITE_OK ){
+      sqlite3_result_int(pCtx, nIndex);
+    }else{
+      sqlite3_result_error(pCtx, sqlite3_errmsg(db), -1);
+    }
+  }
+
+  sqlite3_free(zErrmsg);
+}
+
+/*
+** If the RBU database contains the rbu_count table, use it to initialize
+** the sqlite3rbu.nPhaseOneStep variable. The schema of the rbu_count table
+** is assumed to contain the same columns as:
+**
+**   CREATE TABLE rbu_count(tbl TEXT PRIMARY KEY, cnt INTEGER) WITHOUT ROWID;
+**
+** There should be one row in the table for each data_xxx table in the
+** database. The 'tbl' column should contain the name of a data_xxx table,
+** and the cnt column the number of rows it contains.
+**
+** sqlite3rbu.nPhaseOneStep is initialized to the sum of (1 + nIndex) * cnt
+** for all rows in the rbu_count table, where nIndex is the number of
+** indexes on the corresponding target database table.
+*/
+static void rbuInitPhaseOneSteps(sqlite3rbu *p){
+  if( p->rc==SQLITE_OK ){
+    sqlite3_stmt *pStmt = 0;
+    int bExists = 0;                /* True if rbu_count exists */
+
+    p->nPhaseOneStep = -1;
+
+    p->rc = sqlite3_create_function(p->dbRbu,
+        "rbu_index_cnt", 1, SQLITE_UTF8, (void*)p, rbuIndexCntFunc, 0, 0
+    );
+
+    /* Check for the rbu_count table. If it does not exist, or if an error
+    ** occurs, nPhaseOneStep will be left set to -1. */
+    if( p->rc==SQLITE_OK ){
+      p->rc = prepareAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
+          "SELECT 1 FROM sqlite_schema WHERE tbl_name = 'rbu_count'"
+      );
+    }
+    if( p->rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        bExists = 1;
+      }
+      p->rc = sqlite3_finalize(pStmt);
+    }
+
+    if( p->rc==SQLITE_OK && bExists ){
+      p->rc = prepareAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
+          "SELECT sum(cnt * (1 + rbu_index_cnt(rbu_target_name(tbl))))"
+          "FROM rbu_count"
+      );
+      if( p->rc==SQLITE_OK ){
+        if( SQLITE_ROW==sqlite3_step(pStmt) ){
+          p->nPhaseOneStep = sqlite3_column_int64(pStmt, 0);
+        }
+        p->rc = sqlite3_finalize(pStmt);
+      }
+    }
+  }
+}
+
+
+static sqlite3rbu *openRbuHandle(
+  const char *zTarget,
+  const char *zRbu,
+  const char *zState
+){
+  sqlite3rbu *p;
+  size_t nTarget = zTarget ? strlen(zTarget) : 0;
+  size_t nRbu = strlen(zRbu);
+  size_t nByte = sizeof(sqlite3rbu) + nTarget+1 + nRbu+1;
+
+  p = (sqlite3rbu*)sqlite3_malloc64(nByte);
+  if( p ){
+    RbuState *pState = 0;
+
+    /* Create the custom VFS. */
+    memset(p, 0, sizeof(sqlite3rbu));
+    sqlite3rbu_rename_handler(p, 0, 0);
+    rbuCreateVfs(p);
+
+    /* Open the target, RBU and state databases */
+    if( p->rc==SQLITE_OK ){
+      char *pCsr = (char*)&p[1];
+      int bRetry = 0;
+      if( zTarget ){
+        p->zTarget = pCsr;
+        memcpy(p->zTarget, zTarget, nTarget+1);
+        pCsr += nTarget+1;
+      }
+      p->zRbu = pCsr;
+      memcpy(p->zRbu, zRbu, nRbu+1);
+      pCsr += nRbu+1;
+      if( zState ){
+        p->zState = rbuMPrintf(p, "%s", zState);
+      }
+
+      /* If the first attempt to open the database file fails and the bRetry
+      ** flag it set, this means that the db was not opened because it seemed
+      ** to be a wal-mode db. But, this may have happened due to an earlier
+      ** RBU vacuum operation leaving an old wal file in the directory.
+      ** If this is the case, it will have been checkpointed and deleted
+      ** when the handle was closed and a second attempt to open the
+      ** database may succeed.  */
+      rbuOpenDatabase(p, 0, &bRetry);
+      if( bRetry ){
+        rbuOpenDatabase(p, 0, 0);
+      }
+    }
+
+    if( p->rc==SQLITE_OK ){
+      pState = rbuLoadState(p);
+      assert( pState || p->rc!=SQLITE_OK );
+      if( p->rc==SQLITE_OK ){
+
+        if( pState->eStage==0 ){
+          rbuDeleteOalFile(p);
+          rbuInitPhaseOneSteps(p);
+          p->eStage = RBU_STAGE_OAL;
+        }else{
+          p->eStage = pState->eStage;
+          p->nPhaseOneStep = pState->nPhaseOneStep;
+        }
+        p->nProgress = pState->nProgress;
+        p->iOalSz = pState->iOalSz;
+      }
+    }
+    assert( p->rc!=SQLITE_OK || p->eStage!=0 );
+
+    if( p->rc==SQLITE_OK && p->pTargetFd->pWalFd ){
+      if( p->eStage==RBU_STAGE_OAL ){
+        p->rc = SQLITE_ERROR;
+        p->zErrmsg = sqlite3_mprintf("cannot update wal mode database");
+      }else if( p->eStage==RBU_STAGE_MOVE ){
+        p->eStage = RBU_STAGE_CKPT;
+        p->nStep = 0;
+      }
+    }
+
+    if( p->rc==SQLITE_OK
+     && (p->eStage==RBU_STAGE_OAL || p->eStage==RBU_STAGE_MOVE)
+     && pState->eStage!=0
+    ){
+      rbu_file *pFd = (rbuIsVacuum(p) ? p->pRbuFd : p->pTargetFd);
+      if( pFd->iCookie!=pState->iCookie ){
+        /* At this point (pTargetFd->iCookie) contains the value of the
+        ** change-counter cookie (the thing that gets incremented when a
+        ** transaction is committed in rollback mode) currently stored on
+        ** page 1 of the database file. */
+        p->rc = SQLITE_BUSY;
+        p->zErrmsg = sqlite3_mprintf("database modified during rbu %s",
+            (rbuIsVacuum(p) ? "vacuum" : "update")
+        );
+      }
+    }
+
+    if( p->rc==SQLITE_OK ){
+      if( p->eStage==RBU_STAGE_OAL ){
+        sqlite3 *db = p->dbMain;
+        p->rc = sqlite3_exec(p->dbRbu, "BEGIN", 0, 0, &p->zErrmsg);
+
+        /* Point the object iterator at the first object */
+        if( p->rc==SQLITE_OK ){
+          p->rc = rbuObjIterFirst(p, &p->objiter);
+        }
+
+        /* If the RBU database contains no data_xxx tables, declare the RBU
+        ** update finished.  */
+        if( p->rc==SQLITE_OK && p->objiter.zTbl==0 ){
+          p->rc = SQLITE_DONE;
+          p->eStage = RBU_STAGE_DONE;
+        }else{
+          if( p->rc==SQLITE_OK && pState->eStage==0 && rbuIsVacuum(p) ){
+            rbuCopyPragma(p, "page_size");
+            rbuCopyPragma(p, "auto_vacuum");
+          }
+
+          /* Open transactions both databases. The *-oal file is opened or
+          ** created at this point. */
+          if( p->rc==SQLITE_OK ){
+            p->rc = sqlite3_exec(db, "BEGIN IMMEDIATE", 0, 0, &p->zErrmsg);
+          }
+
+          /* Check if the main database is a zipvfs db. If it is, set the upper
+          ** level pager to use "journal_mode=off". This prevents it from
+          ** generating a large journal using a temp file.  */
+          if( p->rc==SQLITE_OK ){
+            int frc = sqlite3_file_control(db, "main", SQLITE_FCNTL_ZIPVFS, 0);
+            if( frc==SQLITE_OK ){
+              p->rc = sqlite3_exec(
+                db, "PRAGMA journal_mode=off",0,0,&p->zErrmsg);
+            }
+          }
+
+          if( p->rc==SQLITE_OK ){
+            rbuSetupOal(p, pState);
+          }
+        }
+      }else if( p->eStage==RBU_STAGE_MOVE ){
+        /* no-op */
+      }else if( p->eStage==RBU_STAGE_CKPT ){
+        if( !rbuIsVacuum(p) && rbuExclusiveCheckpoint(p->dbMain) ){
+          /* If the rbu_exclusive_checkpoint=1 URI parameter was specified
+          ** and an incremental checkpoint is being resumed, attempt an
+          ** exclusive lock on the db file. If this fails, so be it.  */
+          p->eStage = RBU_STAGE_DONE;
+          rbuLockDatabase(p->dbMain);
+          p->eStage = RBU_STAGE_CKPT;
+        }
+        rbuSetupCheckpoint(p, pState);
+      }else if( p->eStage==RBU_STAGE_DONE ){
+        p->rc = SQLITE_DONE;
+      }else{
+        p->rc = SQLITE_CORRUPT;
+      }
+    }
+
+    rbuFreeState(pState);
+  }
+
+  return p;
+}
+
+/*
+** Allocate and return an RBU handle with all fields zeroed except for the
+** error code, which is set to SQLITE_MISUSE.
+*/
+static sqlite3rbu *rbuMisuseError(void){
+  sqlite3rbu *pRet;
+  pRet = sqlite3_malloc64(sizeof(sqlite3rbu));
+  if( pRet ){
+    memset(pRet, 0, sizeof(sqlite3rbu));
+    pRet->rc = SQLITE_MISUSE;
+  }
+  return pRet;
+}
+
+/*
+** Open and return a new RBU handle.
+*/
+SQLITE_API sqlite3rbu *sqlite3rbu_open(
+  const char *zTarget,
+  const char *zRbu,
+  const char *zState
+){
+  if( zTarget==0 || zRbu==0 ){ return rbuMisuseError(); }
+  return openRbuHandle(zTarget, zRbu, zState);
+}
+
+/*
+** Open a handle to begin or resume an RBU VACUUM operation.
+*/
+SQLITE_API sqlite3rbu *sqlite3rbu_vacuum(
+  const char *zTarget,
+  const char *zState
+){
+  if( zTarget==0 ){ return rbuMisuseError(); }
+  if( zState ){
+    size_t n = strlen(zState);
+    if( n>=7 && 0==memcmp("-vactmp", &zState[n-7], 7) ){
+      return rbuMisuseError();
+    }
+  }
+  /* TODO: Check that both arguments are non-NULL */
+  return openRbuHandle(0, zTarget, zState);
+}
+
+/*
+** Return the database handle used by pRbu.
+*/
+SQLITE_API sqlite3 *sqlite3rbu_db(sqlite3rbu *pRbu, int bRbu){
+  sqlite3 *db = 0;
+  if( pRbu ){
+    db = (bRbu ? pRbu->dbRbu : pRbu->dbMain);
+  }
+  return db;
+}
+
+
+/*
+** If the error code currently stored in the RBU handle is SQLITE_CONSTRAINT,
+** then edit any error message string so as to remove all occurrences of
+** the pattern "rbu_imp_[0-9]*".
+*/
+static void rbuEditErrmsg(sqlite3rbu *p){
+  if( p->rc==SQLITE_CONSTRAINT && p->zErrmsg ){
+    unsigned int i;
+    size_t nErrmsg = strlen(p->zErrmsg);
+    for(i=0; i<(nErrmsg-8); i++){
+      if( memcmp(&p->zErrmsg[i], "rbu_imp_", 8)==0 ){
+        int nDel = 8;
+        while( p->zErrmsg[i+nDel]>='0' && p->zErrmsg[i+nDel]<='9' ) nDel++;
+        memmove(&p->zErrmsg[i], &p->zErrmsg[i+nDel], nErrmsg + 1 - i - nDel);
+        nErrmsg -= nDel;
+      }
+    }
+  }
+}
+
+/*
+** Close the RBU handle.
+*/
+SQLITE_API int sqlite3rbu_close(sqlite3rbu *p, char **pzErrmsg){
+  int rc;
+  if( p ){
+
+    /* Commit the transaction to the *-oal file. */
+    if( p->rc==SQLITE_OK && p->eStage==RBU_STAGE_OAL ){
+      p->rc = sqlite3_exec(p->dbMain, "COMMIT", 0, 0, &p->zErrmsg);
+    }
+
+    /* Sync the db file if currently doing an incremental checkpoint */
+    if( p->rc==SQLITE_OK && p->eStage==RBU_STAGE_CKPT ){
+      sqlite3_file *pDb = p->pTargetFd->pReal;
+      p->rc = pDb->pMethods->xSync(pDb, SQLITE_SYNC_NORMAL);
+    }
+
+    rbuSaveState(p, p->eStage);
+
+    if( p->rc==SQLITE_OK && p->eStage==RBU_STAGE_OAL ){
+      p->rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, &p->zErrmsg);
+    }
+
+    /* Close any open statement handles. */
+    rbuObjIterFinalize(&p->objiter);
+
+    /* If this is an RBU vacuum handle and the vacuum has either finished
+    ** successfully or encountered an error, delete the contents of the
+    ** state table. This causes the next call to sqlite3rbu_vacuum()
+    ** specifying the current target and state databases to start a new
+    ** vacuum from scratch.  */
+    if( rbuIsVacuum(p) && p->rc!=SQLITE_OK && p->dbRbu ){
+      int rc2 = sqlite3_exec(p->dbRbu, "DELETE FROM stat.rbu_state", 0, 0, 0);
+      if( p->rc==SQLITE_DONE && rc2!=SQLITE_OK ) p->rc = rc2;
+    }
+
+    /* Close the open database handle and VFS object. */
+    sqlite3_close(p->dbRbu);
+    sqlite3_close(p->dbMain);
+    assert( p->szTemp==0 );
+    rbuDeleteVfs(p);
+    sqlite3_free(p->aBuf);
+    sqlite3_free(p->aFrame);
+
+    rbuEditErrmsg(p);
+    rc = p->rc;
+    if( pzErrmsg ){
+      *pzErrmsg = p->zErrmsg;
+    }else{
+      sqlite3_free(p->zErrmsg);
+    }
+    sqlite3_free(p->zState);
+    sqlite3_free(p);
+  }else{
+    rc = SQLITE_NOMEM;
+    *pzErrmsg = 0;
+  }
+  return rc;
+}
+
+/*
+** Return the total number of key-value operations (inserts, deletes or
+** updates) that have been performed on the target database since the
+** current RBU update was started.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_progress(sqlite3rbu *pRbu){
+  return pRbu->nProgress;
+}
+
+/*
+** Return permyriadage progress indications for the two main stages of
+** an RBU update.
+*/
+SQLITE_API void sqlite3rbu_bp_progress(sqlite3rbu *p, int *pnOne, int *pnTwo){
+  const int MAX_PROGRESS = 10000;
+  switch( p->eStage ){
+    case RBU_STAGE_OAL:
+      if( p->nPhaseOneStep>0 ){
+        *pnOne = (int)(MAX_PROGRESS * (i64)p->nProgress/(i64)p->nPhaseOneStep);
+      }else{
+        *pnOne = -1;
+      }
+      *pnTwo = 0;
+      break;
+
+    case RBU_STAGE_MOVE:
+      *pnOne = MAX_PROGRESS;
+      *pnTwo = 0;
+      break;
+
+    case RBU_STAGE_CKPT:
+      *pnOne = MAX_PROGRESS;
+      *pnTwo = (int)(MAX_PROGRESS * (i64)p->nStep / (i64)p->nFrame);
+      break;
+
+    case RBU_STAGE_DONE:
+      *pnOne = MAX_PROGRESS;
+      *pnTwo = MAX_PROGRESS;
+      break;
+
+    default:
+      assert( 0 );
+  }
+}
+
+/*
+** Return the current state of the RBU vacuum or update operation.
+*/
+SQLITE_API int sqlite3rbu_state(sqlite3rbu *p){
+  int aRes[] = {
+    0, SQLITE_RBU_STATE_OAL, SQLITE_RBU_STATE_MOVE,
+    0, SQLITE_RBU_STATE_CHECKPOINT, SQLITE_RBU_STATE_DONE
+  };
+
+  assert( RBU_STAGE_OAL==1 );
+  assert( RBU_STAGE_MOVE==2 );
+  assert( RBU_STAGE_CKPT==4 );
+  assert( RBU_STAGE_DONE==5 );
+  assert( aRes[RBU_STAGE_OAL]==SQLITE_RBU_STATE_OAL );
+  assert( aRes[RBU_STAGE_MOVE]==SQLITE_RBU_STATE_MOVE );
+  assert( aRes[RBU_STAGE_CKPT]==SQLITE_RBU_STATE_CHECKPOINT );
+  assert( aRes[RBU_STAGE_DONE]==SQLITE_RBU_STATE_DONE );
+
+  if( p->rc!=SQLITE_OK && p->rc!=SQLITE_DONE ){
+    return SQLITE_RBU_STATE_ERROR;
+  }else{
+    assert( p->rc!=SQLITE_DONE || p->eStage==RBU_STAGE_DONE );
+    assert( p->eStage==RBU_STAGE_OAL
+         || p->eStage==RBU_STAGE_MOVE
+         || p->eStage==RBU_STAGE_CKPT
+         || p->eStage==RBU_STAGE_DONE
+    );
+    return aRes[p->eStage];
+  }
+}
+
+SQLITE_API int sqlite3rbu_savestate(sqlite3rbu *p){
+  int rc = p->rc;
+  if( rc==SQLITE_DONE ) return SQLITE_OK;
+
+  assert( p->eStage>=RBU_STAGE_OAL && p->eStage<=RBU_STAGE_DONE );
+  if( p->eStage==RBU_STAGE_OAL ){
+    assert( rc!=SQLITE_DONE );
+    if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbMain, "COMMIT", 0, 0, 0);
+  }
+
+  /* Sync the db file */
+  if( rc==SQLITE_OK && p->eStage==RBU_STAGE_CKPT ){
+    sqlite3_file *pDb = p->pTargetFd->pReal;
+    rc = pDb->pMethods->xSync(pDb, SQLITE_SYNC_NORMAL);
+  }
+
+  p->rc = rc;
+  rbuSaveState(p, p->eStage);
+  rc = p->rc;
+
+  if( p->eStage==RBU_STAGE_OAL ){
+    assert( rc!=SQLITE_DONE );
+    if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, 0);
+    if( rc==SQLITE_OK ){
+      const char *zBegin = rbuIsVacuum(p) ? "BEGIN" : "BEGIN IMMEDIATE";
+      rc = sqlite3_exec(p->dbRbu, zBegin, 0, 0, 0);
+    }
+    if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbMain, "BEGIN IMMEDIATE", 0, 0,0);
+  }
+
+  p->rc = rc;
+  return rc;
+}
+
+/*
+** Default xRename callback for RBU.
+*/
+static int xDefaultRename(void *pArg, const char *zOld, const char *zNew){
+  int rc = SQLITE_OK;
+  UNUSED_PARAMETER(pArg);
+#if defined(_WIN32_WCE)
+  {
+    LPWSTR zWideOld;
+    LPWSTR zWideNew;
+
+    zWideOld = rbuWinUtf8ToUnicode(zOld);
+    if( zWideOld ){
+      zWideNew = rbuWinUtf8ToUnicode(zNew);
+      if( zWideNew ){
+        if( MoveFileW(zWideOld, zWideNew) ){
+          rc = SQLITE_OK;
+        }else{
+          rc = SQLITE_IOERR;
+        }
+        sqlite3_free(zWideNew);
+      }else{
+        rc = SQLITE_IOERR_NOMEM;
+      }
+      sqlite3_free(zWideOld);
+    }else{
+      rc = SQLITE_IOERR_NOMEM;
+    }
+  }
+#else
+  rc = rename(zOld, zNew) ? SQLITE_IOERR : SQLITE_OK;
+#endif
+  return rc;
+}
+
+SQLITE_API void sqlite3rbu_rename_handler(
+  sqlite3rbu *pRbu,
+  void *pArg,
+  int (*xRename)(void *pArg, const char *zOld, const char *zNew)
+){
+  if( xRename ){
+    pRbu->xRename = xRename;
+    pRbu->pRenameArg = pArg;
+  }else{
+    pRbu->xRename = xDefaultRename;
+    pRbu->pRenameArg = 0;
+  }
+}
+
+/**************************************************************************
+** Beginning of RBU VFS shim methods. The VFS shim modifies the behaviour
+** of a standard VFS in the following ways:
+**
+** 1. Whenever the first page of a main database file is read or
+**    written, the value of the change-counter cookie is stored in
+**    rbu_file.iCookie. Similarly, the value of the "write-version"
+**    database header field is stored in rbu_file.iWriteVer. This ensures
+**    that the values are always trustworthy within an open transaction.
+**
+** 2. Whenever an SQLITE_OPEN_WAL file is opened, the (rbu_file.pWalFd)
+**    member variable of the associated database file descriptor is set
+**    to point to the new file. A mutex protected linked list of all main
+**    db fds opened using a particular RBU VFS is maintained at
+**    rbu_vfs.pMain to facilitate this.
+**
+** 3. Using a new file-control "SQLITE_FCNTL_RBU", a main db rbu_file
+**    object can be marked as the target database of an RBU update. This
+**    turns on the following extra special behaviour:
+**
+** 3a. If xAccess() is called to check if there exists a *-wal file
+**     associated with an RBU target database currently in RBU_STAGE_OAL
+**     stage (preparing the *-oal file), the following special handling
+**     applies:
+**
+**      * if the *-wal file does exist, return SQLITE_CANTOPEN. An RBU
+**        target database may not be in wal mode already.
+**
+**      * if the *-wal file does not exist, set the output parameter to
+**        non-zero (to tell SQLite that it does exist) anyway.
+**
+**     Then, when xOpen() is called to open the *-wal file associated with
+**     the RBU target in RBU_STAGE_OAL stage, instead of opening the *-wal
+**     file, the rbu vfs opens the corresponding *-oal file instead.
+**
+** 3b. The *-shm pages returned by xShmMap() for a target db file in
+**     RBU_STAGE_OAL mode are actually stored in heap memory. This is to
+**     avoid creating a *-shm file on disk. Additionally, xShmLock() calls
+**     are no-ops on target database files in RBU_STAGE_OAL mode. This is
+**     because assert() statements in some VFS implementations fail if
+**     xShmLock() is called before xShmMap().
+**
+** 3c. If an EXCLUSIVE lock is attempted on a target database file in any
+**     mode except RBU_STAGE_DONE (all work completed and checkpointed), it
+**     fails with an SQLITE_BUSY error. This is to stop RBU connections
+**     from automatically checkpointing a *-wal (or *-oal) file from within
+**     sqlite3_close().
+**
+** 3d. In RBU_STAGE_CAPTURE mode, all xRead() calls on the wal file, and
+**     all xWrite() calls on the target database file perform no IO.
+**     Instead the frame and page numbers that would be read and written
+**     are recorded. Additionally, successful attempts to obtain exclusive
+**     xShmLock() WRITER, CHECKPOINTER and READ0 locks on the target
+**     database file are recorded. xShmLock() calls to unlock the same
+**     locks are no-ops (so that once obtained, these locks are never
+**     relinquished). Finally, calls to xSync() on the target database
+**     file fail with SQLITE_NOTICE errors.
+*/
+
+static void rbuUnlockShm(rbu_file *p){
+  assert( p->openFlags & SQLITE_OPEN_MAIN_DB );
+  if( p->pRbu ){
+    int (*xShmLock)(sqlite3_file*,int,int,int) = p->pReal->pMethods->xShmLock;
+    int i;
+    for(i=0; i<SQLITE_SHM_NLOCK;i++){
+      if( (1<<i) & p->pRbu->mLock ){
+        xShmLock(p->pReal, i, 1, SQLITE_SHM_UNLOCK|SQLITE_SHM_EXCLUSIVE);
+      }
+    }
+    p->pRbu->mLock = 0;
+  }
+}
+
+/*
+*/
+static int rbuUpdateTempSize(rbu_file *pFd, sqlite3_int64 nNew){
+  sqlite3rbu *pRbu = pFd->pRbu;
+  i64 nDiff = nNew - pFd->sz;
+  pRbu->szTemp += nDiff;
+  pFd->sz = nNew;
+  assert( pRbu->szTemp>=0 );
+  if( pRbu->szTempLimit && pRbu->szTemp>pRbu->szTempLimit ) return SQLITE_FULL;
+  return SQLITE_OK;
+}
+
+/*
+** Add an item to the main-db lists, if it is not already present.
+**
+** There are two main-db lists. One for all file descriptors, and one
+** for all file descriptors with rbu_file.pDb!=0. If the argument has
+** rbu_file.pDb!=0, then it is assumed to already be present on the
+** main list and is only added to the pDb!=0 list.
+*/
+static void rbuMainlistAdd(rbu_file *p){
+  rbu_vfs *pRbuVfs = p->pRbuVfs;
+  rbu_file *pIter;
+  assert( (p->openFlags & SQLITE_OPEN_MAIN_DB) );
+  sqlite3_mutex_enter(pRbuVfs->mutex);
+  if( p->pRbu==0 ){
+    for(pIter=pRbuVfs->pMain; pIter; pIter=pIter->pMainNext);
+    p->pMainNext = pRbuVfs->pMain;
+    pRbuVfs->pMain = p;
+  }else{
+    for(pIter=pRbuVfs->pMainRbu; pIter && pIter!=p; pIter=pIter->pMainRbuNext){}
+    if( pIter==0 ){
+      p->pMainRbuNext = pRbuVfs->pMainRbu;
+      pRbuVfs->pMainRbu = p;
+    }
+  }
+  sqlite3_mutex_leave(pRbuVfs->mutex);
+}
+
+/*
+** Remove an item from the main-db lists.
+*/
+static void rbuMainlistRemove(rbu_file *p){
+  rbu_file **pp;
+  sqlite3_mutex_enter(p->pRbuVfs->mutex);
+  for(pp=&p->pRbuVfs->pMain; *pp && *pp!=p; pp=&((*pp)->pMainNext)){}
+  if( *pp ) *pp = p->pMainNext;
+  p->pMainNext = 0;
+  for(pp=&p->pRbuVfs->pMainRbu; *pp && *pp!=p; pp=&((*pp)->pMainRbuNext)){}
+  if( *pp ) *pp = p->pMainRbuNext;
+  p->pMainRbuNext = 0;
+  sqlite3_mutex_leave(p->pRbuVfs->mutex);
+}
+
+/*
+** Given that zWal points to a buffer containing a wal file name passed to
+** either the xOpen() or xAccess() VFS method, search the main-db list for
+** a file-handle opened by the same database connection on the corresponding
+** database file.
+**
+** If parameter bRbu is true, only search for file-descriptors with
+** rbu_file.pDb!=0.
+*/
+static rbu_file *rbuFindMaindb(rbu_vfs *pRbuVfs, const char *zWal, int bRbu){
+  rbu_file *pDb;
+  sqlite3_mutex_enter(pRbuVfs->mutex);
+  if( bRbu ){
+    for(pDb=pRbuVfs->pMainRbu; pDb && pDb->zWal!=zWal; pDb=pDb->pMainRbuNext){}
+  }else{
+    for(pDb=pRbuVfs->pMain; pDb && pDb->zWal!=zWal; pDb=pDb->pMainNext){}
+  }
+  sqlite3_mutex_leave(pRbuVfs->mutex);
+  return pDb;
+}
+
+/*
+** Close an rbu file.
+*/
+static int rbuVfsClose(sqlite3_file *pFile){
+  rbu_file *p = (rbu_file*)pFile;
+  int rc;
+  int i;
+
+  /* Free the contents of the apShm[] array. And the array itself. */
+  for(i=0; i<p->nShm; i++){
+    sqlite3_free(p->apShm[i]);
+  }
+  sqlite3_free(p->apShm);
+  p->apShm = 0;
+  sqlite3_free(p->zDel);
+
+  if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
+    const sqlite3_io_methods *pMeth = p->pReal->pMethods;
+    rbuMainlistRemove(p);
+    rbuUnlockShm(p);
+    if( pMeth->iVersion>1 && pMeth->xShmUnmap ){
+      pMeth->xShmUnmap(p->pReal, 0);
+    }
+  }
+  else if( (p->openFlags & SQLITE_OPEN_DELETEONCLOSE) && p->pRbu ){
+    rbuUpdateTempSize(p, 0);
+  }
+  assert( p->pMainNext==0 && p->pRbuVfs->pMain!=p );
+
+  /* Close the underlying file handle */
+  rc = p->pReal->pMethods->xClose(p->pReal);
+  return rc;
+}
+
+
+/*
+** Read and return an unsigned 32-bit big-endian integer from the buffer
+** passed as the only argument.
+*/
+static u32 rbuGetU32(u8 *aBuf){
+  return ((u32)aBuf[0] << 24)
+       + ((u32)aBuf[1] << 16)
+       + ((u32)aBuf[2] <<  8)
+       + ((u32)aBuf[3]);
+}
+
+/*
+** Write an unsigned 32-bit value in big-endian format to the supplied
+** buffer.
+*/
+static void rbuPutU32(u8 *aBuf, u32 iVal){
+  aBuf[0] = (iVal >> 24) & 0xFF;
+  aBuf[1] = (iVal >> 16) & 0xFF;
+  aBuf[2] = (iVal >>  8) & 0xFF;
+  aBuf[3] = (iVal >>  0) & 0xFF;
+}
+
+static void rbuPutU16(u8 *aBuf, u16 iVal){
+  aBuf[0] = (iVal >>  8) & 0xFF;
+  aBuf[1] = (iVal >>  0) & 0xFF;
+}
+
+/*
+** Read data from an rbuVfs-file.
+*/
+static int rbuVfsRead(
+  sqlite3_file *pFile,
+  void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  rbu_file *p = (rbu_file*)pFile;
+  sqlite3rbu *pRbu = p->pRbu;
+  int rc;
+
+  if( pRbu && pRbu->eStage==RBU_STAGE_CAPTURE ){
+    assert( p->openFlags & SQLITE_OPEN_WAL );
+    rc = rbuCaptureWalRead(p->pRbu, iOfst, iAmt);
+  }else{
+    if( pRbu && pRbu->eStage==RBU_STAGE_OAL
+     && (p->openFlags & SQLITE_OPEN_WAL)
+     && iOfst>=pRbu->iOalSz
+    ){
+      rc = SQLITE_OK;
+      memset(zBuf, 0, iAmt);
+    }else{
+      rc = p->pReal->pMethods->xRead(p->pReal, zBuf, iAmt, iOfst);
+#if 1
+      /* If this is being called to read the first page of the target
+      ** database as part of an rbu vacuum operation, synthesize the
+      ** contents of the first page if it does not yet exist. Otherwise,
+      ** SQLite will not check for a *-wal file.  */
+      if( pRbu && rbuIsVacuum(pRbu)
+          && rc==SQLITE_IOERR_SHORT_READ && iOfst==0
+          && (p->openFlags & SQLITE_OPEN_MAIN_DB)
+          && pRbu->rc==SQLITE_OK
+      ){
+        sqlite3_file *pFd = (sqlite3_file*)pRbu->pRbuFd;
+        rc = pFd->pMethods->xRead(pFd, zBuf, iAmt, iOfst);
+        if( rc==SQLITE_OK ){
+          u8 *aBuf = (u8*)zBuf;
+          u32 iRoot = rbuGetU32(&aBuf[52]) ? 1 : 0;
+          rbuPutU32(&aBuf[52], iRoot);      /* largest root page number */
+          rbuPutU32(&aBuf[36], 0);          /* number of free pages */
+          rbuPutU32(&aBuf[32], 0);          /* first page on free list trunk */
+          rbuPutU32(&aBuf[28], 1);          /* size of db file in pages */
+          rbuPutU32(&aBuf[24], pRbu->pRbuFd->iCookie+1);  /* Change counter */
+
+          if( iAmt>100 ){
+            memset(&aBuf[100], 0, iAmt-100);
+            rbuPutU16(&aBuf[105], iAmt & 0xFFFF);
+            aBuf[100] = 0x0D;
+          }
+        }
+      }
+#endif
+    }
+    if( rc==SQLITE_OK && iOfst==0 && (p->openFlags & SQLITE_OPEN_MAIN_DB) ){
+      /* These look like magic numbers. But they are stable, as they are part
+       ** of the definition of the SQLite file format, which may not change. */
+      u8 *pBuf = (u8*)zBuf;
+      p->iCookie = rbuGetU32(&pBuf[24]);
+      p->iWriteVer = pBuf[19];
+    }
+  }
+  return rc;
+}
+
+/*
+** Write data to an rbuVfs-file.
+*/
+static int rbuVfsWrite(
+  sqlite3_file *pFile,
+  const void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  rbu_file *p = (rbu_file*)pFile;
+  sqlite3rbu *pRbu = p->pRbu;
+  int rc;
+
+  if( pRbu && pRbu->eStage==RBU_STAGE_CAPTURE ){
+    assert( p->openFlags & SQLITE_OPEN_MAIN_DB );
+    rc = rbuCaptureDbWrite(p->pRbu, iOfst);
+  }else{
+    if( pRbu ){
+      if( pRbu->eStage==RBU_STAGE_OAL
+       && (p->openFlags & SQLITE_OPEN_WAL)
+       && iOfst>=pRbu->iOalSz
+      ){
+        pRbu->iOalSz = iAmt + iOfst;
+      }else if( p->openFlags & SQLITE_OPEN_DELETEONCLOSE ){
+        i64 szNew = iAmt+iOfst;
+        if( szNew>p->sz ){
+          rc = rbuUpdateTempSize(p, szNew);
+          if( rc!=SQLITE_OK ) return rc;
+        }
+      }
+    }
+    rc = p->pReal->pMethods->xWrite(p->pReal, zBuf, iAmt, iOfst);
+    if( rc==SQLITE_OK && iOfst==0 && (p->openFlags & SQLITE_OPEN_MAIN_DB) ){
+      /* These look like magic numbers. But they are stable, as they are part
+      ** of the definition of the SQLite file format, which may not change. */
+      u8 *pBuf = (u8*)zBuf;
+      p->iCookie = rbuGetU32(&pBuf[24]);
+      p->iWriteVer = pBuf[19];
+    }
+  }
+  return rc;
+}
+
+/*
+** Truncate an rbuVfs-file.
+*/
+static int rbuVfsTruncate(sqlite3_file *pFile, sqlite_int64 size){
+  rbu_file *p = (rbu_file*)pFile;
+  if( (p->openFlags & SQLITE_OPEN_DELETEONCLOSE) && p->pRbu ){
+    int rc = rbuUpdateTempSize(p, size);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  return p->pReal->pMethods->xTruncate(p->pReal, size);
+}
+
+/*
+** Sync an rbuVfs-file.
+*/
+static int rbuVfsSync(sqlite3_file *pFile, int flags){
+  rbu_file *p = (rbu_file *)pFile;
+  if( p->pRbu && p->pRbu->eStage==RBU_STAGE_CAPTURE ){
+    if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
+      return SQLITE_NOTICE_RBU;
+    }
+    return SQLITE_OK;
+  }
+  return p->pReal->pMethods->xSync(p->pReal, flags);
+}
+
+/*
+** Return the current file-size of an rbuVfs-file.
+*/
+static int rbuVfsFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
+  rbu_file *p = (rbu_file *)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xFileSize(p->pReal, pSize);
+
+  /* If this is an RBU vacuum operation and this is the target database,
+  ** pretend that it has at least one page. Otherwise, SQLite will not
+  ** check for the existance of a *-wal file. rbuVfsRead() contains
+  ** similar logic.  */
+  if( rc==SQLITE_OK && *pSize==0
+   && p->pRbu && rbuIsVacuum(p->pRbu)
+   && (p->openFlags & SQLITE_OPEN_MAIN_DB)
+  ){
+    *pSize = 1024;
+  }
+  return rc;
+}
+
+/*
+** Lock an rbuVfs-file.
+*/
+static int rbuVfsLock(sqlite3_file *pFile, int eLock){
+  rbu_file *p = (rbu_file*)pFile;
+  sqlite3rbu *pRbu = p->pRbu;
+  int rc = SQLITE_OK;
+
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
+  if( eLock==SQLITE_LOCK_EXCLUSIVE
+   && (p->bNolock || (pRbu && pRbu->eStage!=RBU_STAGE_DONE))
+  ){
+    /* Do not allow EXCLUSIVE locks. Preventing SQLite from taking this
+    ** prevents it from checkpointing the database from sqlite3_close(). */
+    rc = SQLITE_BUSY;
+  }else{
+    rc = p->pReal->pMethods->xLock(p->pReal, eLock);
+  }
+
+  return rc;
+}
+
+/*
+** Unlock an rbuVfs-file.
+*/
+static int rbuVfsUnlock(sqlite3_file *pFile, int eLock){
+  rbu_file *p = (rbu_file *)pFile;
+  return p->pReal->pMethods->xUnlock(p->pReal, eLock);
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on an rbuVfs-file.
+*/
+static int rbuVfsCheckReservedLock(sqlite3_file *pFile, int *pResOut){
+  rbu_file *p = (rbu_file *)pFile;
+  return p->pReal->pMethods->xCheckReservedLock(p->pReal, pResOut);
+}
+
+/*
+** File control method. For custom operations on an rbuVfs-file.
+*/
+static int rbuVfsFileControl(sqlite3_file *pFile, int op, void *pArg){
+  rbu_file *p = (rbu_file *)pFile;
+  int (*xControl)(sqlite3_file*,int,void*) = p->pReal->pMethods->xFileControl;
+  int rc;
+
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB)
+       || p->openFlags & (SQLITE_OPEN_TRANSIENT_DB|SQLITE_OPEN_TEMP_JOURNAL)
+  );
+  if( op==SQLITE_FCNTL_RBU ){
+    sqlite3rbu *pRbu = (sqlite3rbu*)pArg;
+
+    /* First try to find another RBU vfs lower down in the vfs stack. If
+    ** one is found, this vfs will operate in pass-through mode. The lower
+    ** level vfs will do the special RBU handling.  */
+    rc = xControl(p->pReal, op, pArg);
+
+    if( rc==SQLITE_NOTFOUND ){
+      /* Now search for a zipvfs instance lower down in the VFS stack. If
+      ** one is found, this is an error.  */
+      void *dummy = 0;
+      rc = xControl(p->pReal, SQLITE_FCNTL_ZIPVFS, &dummy);
+      if( rc==SQLITE_OK ){
+        rc = SQLITE_ERROR;
+        pRbu->zErrmsg = sqlite3_mprintf("rbu/zipvfs setup error");
+      }else if( rc==SQLITE_NOTFOUND ){
+        pRbu->pTargetFd = p;
+        p->pRbu = pRbu;
+        rbuMainlistAdd(p);
+        if( p->pWalFd ) p->pWalFd->pRbu = pRbu;
+        rc = SQLITE_OK;
+      }
+    }
+    return rc;
+  }
+  else if( op==SQLITE_FCNTL_RBUCNT ){
+    sqlite3rbu *pRbu = (sqlite3rbu*)pArg;
+    pRbu->nRbu++;
+    pRbu->pRbuFd = p;
+    p->bNolock = 1;
+  }
+
+  rc = xControl(p->pReal, op, pArg);
+  if( rc==SQLITE_OK && op==SQLITE_FCNTL_VFSNAME ){
+    rbu_vfs *pRbuVfs = p->pRbuVfs;
+    char *zIn = *(char**)pArg;
+    char *zOut = sqlite3_mprintf("rbu(%s)/%z", pRbuVfs->base.zName, zIn);
+    *(char**)pArg = zOut;
+    if( zOut==0 ) rc = SQLITE_NOMEM;
+  }
+
+  return rc;
+}
+
+/*
+** Return the sector-size in bytes for an rbuVfs-file.
+*/
+static int rbuVfsSectorSize(sqlite3_file *pFile){
+  rbu_file *p = (rbu_file *)pFile;
+  return p->pReal->pMethods->xSectorSize(p->pReal);
+}
+
+/*
+** Return the device characteristic flags supported by an rbuVfs-file.
+*/
+static int rbuVfsDeviceCharacteristics(sqlite3_file *pFile){
+  rbu_file *p = (rbu_file *)pFile;
+  return p->pReal->pMethods->xDeviceCharacteristics(p->pReal);
+}
+
+/*
+** Take or release a shared-memory lock.
+*/
+static int rbuVfsShmLock(sqlite3_file *pFile, int ofst, int n, int flags){
+  rbu_file *p = (rbu_file*)pFile;
+  sqlite3rbu *pRbu = p->pRbu;
+  int rc = SQLITE_OK;
+
+#ifdef SQLITE_AMALGAMATION
+    assert( WAL_CKPT_LOCK==1 );
+#endif
+
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
+  if( pRbu && (
+       pRbu->eStage==RBU_STAGE_OAL
+    || pRbu->eStage==RBU_STAGE_MOVE
+    || pRbu->eStage==RBU_STAGE_DONE
+  )){
+    /* Prevent SQLite from taking a shm-lock on the target file when it
+    ** is supplying heap memory to the upper layer in place of *-shm
+    ** segments. */
+    if( ofst==WAL_LOCK_CKPT && n==1 ) rc = SQLITE_BUSY;
+  }else{
+    int bCapture = 0;
+    if( pRbu && pRbu->eStage==RBU_STAGE_CAPTURE ){
+      bCapture = 1;
+    }
+    if( bCapture==0 || 0==(flags & SQLITE_SHM_UNLOCK) ){
+      rc = p->pReal->pMethods->xShmLock(p->pReal, ofst, n, flags);
+      if( bCapture && rc==SQLITE_OK ){
+        pRbu->mLock |= ((1<<n) - 1) << ofst;
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Obtain a pointer to a mapping of a single 32KiB page of the *-shm file.
+*/
+static int rbuVfsShmMap(
+  sqlite3_file *pFile,
+  int iRegion,
+  int szRegion,
+  int isWrite,
+  void volatile **pp
+){
+  rbu_file *p = (rbu_file*)pFile;
+  int rc = SQLITE_OK;
+  int eStage = (p->pRbu ? p->pRbu->eStage : 0);
+
+  /* If not in RBU_STAGE_OAL, allow this call to pass through. Or, if this
+  ** rbu is in the RBU_STAGE_OAL state, use heap memory for *-shm space
+  ** instead of a file on disk.  */
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
+  if( eStage==RBU_STAGE_OAL ){
+    sqlite3_int64 nByte = (iRegion+1) * sizeof(char*);
+    char **apNew = (char**)sqlite3_realloc64(p->apShm, nByte);
+
+    /* This is an RBU connection that uses its own heap memory for the
+    ** pages of the *-shm file. Since no other process can have run
+    ** recovery, the connection must request *-shm pages in order
+    ** from start to finish.  */
+    assert( iRegion==p->nShm );
+    if( apNew==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(&apNew[p->nShm], 0, sizeof(char*) * (1 + iRegion - p->nShm));
+      p->apShm = apNew;
+      p->nShm = iRegion+1;
+    }
+
+    if( rc==SQLITE_OK ){
+      char *pNew = (char*)sqlite3_malloc64(szRegion);
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(pNew, 0, szRegion);
+        p->apShm[iRegion] = pNew;
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      *pp = p->apShm[iRegion];
+    }else{
+      *pp = 0;
+    }
+  }else{
+    assert( p->apShm==0 );
+    rc = p->pReal->pMethods->xShmMap(p->pReal, iRegion, szRegion, isWrite, pp);
+  }
+
+  return rc;
+}
+
+/*
+** Memory barrier.
+*/
+static void rbuVfsShmBarrier(sqlite3_file *pFile){
+  rbu_file *p = (rbu_file *)pFile;
+  p->pReal->pMethods->xShmBarrier(p->pReal);
+}
+
+/*
+** The xShmUnmap method.
+*/
+static int rbuVfsShmUnmap(sqlite3_file *pFile, int delFlag){
+  rbu_file *p = (rbu_file*)pFile;
+  int rc = SQLITE_OK;
+  int eStage = (p->pRbu ? p->pRbu->eStage : 0);
+
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
+  if( eStage==RBU_STAGE_OAL || eStage==RBU_STAGE_MOVE ){
+    /* no-op */
+  }else{
+    /* Release the checkpointer and writer locks */
+    rbuUnlockShm(p);
+    rc = p->pReal->pMethods->xShmUnmap(p->pReal, delFlag);
+  }
+  return rc;
+}
+
+/*
+** Open an rbu file handle.
+*/
+static int rbuVfsOpen(
+  sqlite3_vfs *pVfs,
+  const char *zName,
+  sqlite3_file *pFile,
+  int flags,
+  int *pOutFlags
+){
+  static sqlite3_io_methods rbuvfs_io_methods = {
+    2,                            /* iVersion */
+    rbuVfsClose,                  /* xClose */
+    rbuVfsRead,                   /* xRead */
+    rbuVfsWrite,                  /* xWrite */
+    rbuVfsTruncate,               /* xTruncate */
+    rbuVfsSync,                   /* xSync */
+    rbuVfsFileSize,               /* xFileSize */
+    rbuVfsLock,                   /* xLock */
+    rbuVfsUnlock,                 /* xUnlock */
+    rbuVfsCheckReservedLock,      /* xCheckReservedLock */
+    rbuVfsFileControl,            /* xFileControl */
+    rbuVfsSectorSize,             /* xSectorSize */
+    rbuVfsDeviceCharacteristics,  /* xDeviceCharacteristics */
+    rbuVfsShmMap,                 /* xShmMap */
+    rbuVfsShmLock,                /* xShmLock */
+    rbuVfsShmBarrier,             /* xShmBarrier */
+    rbuVfsShmUnmap,               /* xShmUnmap */
+    0, 0                          /* xFetch, xUnfetch */
+  };
+  static sqlite3_io_methods rbuvfs_io_methods1 = {
+    1,                            /* iVersion */
+    rbuVfsClose,                  /* xClose */
+    rbuVfsRead,                   /* xRead */
+    rbuVfsWrite,                  /* xWrite */
+    rbuVfsTruncate,               /* xTruncate */
+    rbuVfsSync,                   /* xSync */
+    rbuVfsFileSize,               /* xFileSize */
+    rbuVfsLock,                   /* xLock */
+    rbuVfsUnlock,                 /* xUnlock */
+    rbuVfsCheckReservedLock,      /* xCheckReservedLock */
+    rbuVfsFileControl,            /* xFileControl */
+    rbuVfsSectorSize,             /* xSectorSize */
+    rbuVfsDeviceCharacteristics,  /* xDeviceCharacteristics */
+    0, 0, 0, 0, 0, 0
+  };
+
+
+
+  rbu_vfs *pRbuVfs = (rbu_vfs*)pVfs;
+  sqlite3_vfs *pRealVfs = pRbuVfs->pRealVfs;
+  rbu_file *pFd = (rbu_file *)pFile;
+  int rc = SQLITE_OK;
+  const char *zOpen = zName;
+  int oflags = flags;
+
+  memset(pFd, 0, sizeof(rbu_file));
+  pFd->pReal = (sqlite3_file*)&pFd[1];
+  pFd->pRbuVfs = pRbuVfs;
+  pFd->openFlags = flags;
+  if( zName ){
+    if( flags & SQLITE_OPEN_MAIN_DB ){
+      /* A main database has just been opened. The following block sets
+      ** (pFd->zWal) to point to a buffer owned by SQLite that contains
+      ** the name of the *-wal file this db connection will use. SQLite
+      ** happens to pass a pointer to this buffer when using xAccess()
+      ** or xOpen() to operate on the *-wal file.  */
+      pFd->zWal = sqlite3_filename_wal(zName);
+    }
+    else if( flags & SQLITE_OPEN_WAL ){
+      rbu_file *pDb = rbuFindMaindb(pRbuVfs, zName, 0);
+      if( pDb ){
+        if( pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
+          /* This call is to open a *-wal file. Intead, open the *-oal. */
+          size_t nOpen;
+          if( rbuIsVacuum(pDb->pRbu) ){
+            zOpen = sqlite3_db_filename(pDb->pRbu->dbRbu, "main");
+            zOpen = sqlite3_filename_wal(zOpen);
+          }
+          nOpen = strlen(zOpen);
+          ((char*)zOpen)[nOpen-3] = 'o';
+          pFd->pRbu = pDb->pRbu;
+        }
+        pDb->pWalFd = pFd;
+      }
+    }
+  }else{
+    pFd->pRbu = pRbuVfs->pRbu;
+  }
+
+  if( oflags & SQLITE_OPEN_MAIN_DB
+   && sqlite3_uri_boolean(zName, "rbu_memory", 0)
+  ){
+    assert( oflags & SQLITE_OPEN_MAIN_DB );
+    oflags =  SQLITE_OPEN_TEMP_DB | SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
+              SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE;
+    zOpen = 0;
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = pRealVfs->xOpen(pRealVfs, zOpen, pFd->pReal, oflags, pOutFlags);
+  }
+  if( pFd->pReal->pMethods ){
+    const sqlite3_io_methods *pMeth = pFd->pReal->pMethods;
+    /* The xOpen() operation has succeeded. Set the sqlite3_file.pMethods
+    ** pointer and, if the file is a main database file, link it into the
+    ** mutex protected linked list of all such files.  */
+    if( pMeth->iVersion<2 || pMeth->xShmLock==0 ){
+      pFile->pMethods = &rbuvfs_io_methods1;
+    }else{
+      pFile->pMethods = &rbuvfs_io_methods;
+    }
+    if( flags & SQLITE_OPEN_MAIN_DB ){
+      rbuMainlistAdd(pFd);
+    }
+  }else{
+    sqlite3_free(pFd->zDel);
+  }
+
+  return rc;
+}
+
+/*
+** Delete the file located at zPath.
+*/
+static int rbuVfsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xDelete(pRealVfs, zPath, dirSync);
+}
+
+/*
+** Test for access permissions. Return true if the requested permission
+** is available, or false otherwise.
+*/
+static int rbuVfsAccess(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int flags,
+  int *pResOut
+){
+  rbu_vfs *pRbuVfs = (rbu_vfs*)pVfs;
+  sqlite3_vfs *pRealVfs = pRbuVfs->pRealVfs;
+  int rc;
+
+  rc = pRealVfs->xAccess(pRealVfs, zPath, flags, pResOut);
+
+  /* If this call is to check if a *-wal file associated with an RBU target
+  ** database connection exists, and the RBU update is in RBU_STAGE_OAL,
+  ** the following special handling is activated:
+  **
+  **   a) if the *-wal file does exist, return SQLITE_CANTOPEN. This
+  **      ensures that the RBU extension never tries to update a database
+  **      in wal mode, even if the first page of the database file has
+  **      been damaged.
+  **
+  **   b) if the *-wal file does not exist, claim that it does anyway,
+  **      causing SQLite to call xOpen() to open it. This call will also
+  **      be intercepted (see the rbuVfsOpen() function) and the *-oal
+  **      file opened instead.
+  */
+  if( rc==SQLITE_OK && flags==SQLITE_ACCESS_EXISTS ){
+    rbu_file *pDb = rbuFindMaindb(pRbuVfs, zPath, 1);
+    if( pDb && pDb->pRbu->eStage==RBU_STAGE_OAL ){
+      assert( pDb->pRbu );
+      if( *pResOut ){
+        rc = SQLITE_CANTOPEN;
+      }else{
+        sqlite3_int64 sz = 0;
+        rc = rbuVfsFileSize(&pDb->base, &sz);
+        *pResOut = (sz>0);
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Populate buffer zOut with the full canonical pathname corresponding
+** to the pathname in zPath. zOut is guaranteed to point to a buffer
+** of at least (DEVSYM_MAX_PATHNAME+1) bytes.
+*/
+static int rbuVfsFullPathname(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int nOut,
+  char *zOut
+){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xFullPathname(pRealVfs, zPath, nOut, zOut);
+}
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Open the dynamic library located at zPath and return a handle.
+*/
+static void *rbuVfsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xDlOpen(pRealVfs, zPath);
+}
+
+/*
+** Populate the buffer zErrMsg (size nByte bytes) with a human readable
+** utf-8 string describing the most recent error encountered associated
+** with dynamic libraries.
+*/
+static void rbuVfsDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  pRealVfs->xDlError(pRealVfs, nByte, zErrMsg);
+}
+
+/*
+** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
+*/
+static void (*rbuVfsDlSym(
+  sqlite3_vfs *pVfs,
+  void *pArg,
+  const char *zSym
+))(void){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xDlSym(pRealVfs, pArg, zSym);
+}
+
+/*
+** Close the dynamic library handle pHandle.
+*/
+static void rbuVfsDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  pRealVfs->xDlClose(pRealVfs, pHandle);
+}
+#endif /* SQLITE_OMIT_LOAD_EXTENSION */
+
+/*
+** Populate the buffer pointed to by zBufOut with nByte bytes of
+** random data.
+*/
+static int rbuVfsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xRandomness(pRealVfs, nByte, zBufOut);
+}
+
+/*
+** Sleep for nMicro microseconds. Return the number of microseconds
+** actually slept.
+*/
+static int rbuVfsSleep(sqlite3_vfs *pVfs, int nMicro){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xSleep(pRealVfs, nMicro);
+}
+
+/*
+** Return the current time as a Julian Day number in *pTimeOut.
+*/
+static int rbuVfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xCurrentTime(pRealVfs, pTimeOut);
+}
+
+/*
+** No-op.
+*/
+static int rbuVfsGetLastError(sqlite3_vfs *pVfs, int a, char *b){
+  UNUSED_PARAMETER(pVfs);
+  UNUSED_PARAMETER(a);
+  UNUSED_PARAMETER(b);
+  return 0;
+}
+
+/*
+** Deregister and destroy an RBU vfs created by an earlier call to
+** sqlite3rbu_create_vfs().
+*/
+SQLITE_API void sqlite3rbu_destroy_vfs(const char *zName){
+  sqlite3_vfs *pVfs = sqlite3_vfs_find(zName);
+  if( pVfs && pVfs->xOpen==rbuVfsOpen ){
+    sqlite3_mutex_free(((rbu_vfs*)pVfs)->mutex);
+    sqlite3_vfs_unregister(pVfs);
+    sqlite3_free(pVfs);
+  }
+}
+
+/*
+** Create an RBU VFS named zName that accesses the underlying file-system
+** via existing VFS zParent. The new object is registered as a non-default
+** VFS with SQLite before returning.
+*/
+SQLITE_API int sqlite3rbu_create_vfs(const char *zName, const char *zParent){
+
+  /* Template for VFS */
+  static sqlite3_vfs vfs_template = {
+    1,                            /* iVersion */
+    0,                            /* szOsFile */
+    0,                            /* mxPathname */
+    0,                            /* pNext */
+    0,                            /* zName */
+    0,                            /* pAppData */
+    rbuVfsOpen,                   /* xOpen */
+    rbuVfsDelete,                 /* xDelete */
+    rbuVfsAccess,                 /* xAccess */
+    rbuVfsFullPathname,           /* xFullPathname */
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+    rbuVfsDlOpen,                 /* xDlOpen */
+    rbuVfsDlError,                /* xDlError */
+    rbuVfsDlSym,                  /* xDlSym */
+    rbuVfsDlClose,                /* xDlClose */
+#else
+    0, 0, 0, 0,
+#endif
+
+    rbuVfsRandomness,             /* xRandomness */
+    rbuVfsSleep,                  /* xSleep */
+    rbuVfsCurrentTime,            /* xCurrentTime */
+    rbuVfsGetLastError,           /* xGetLastError */
+    0,                            /* xCurrentTimeInt64 (version 2) */
+    0, 0, 0                       /* Unimplemented version 3 methods */
+  };
+
+  rbu_vfs *pNew = 0;              /* Newly allocated VFS */
+  int rc = SQLITE_OK;
+  size_t nName;
+  size_t nByte;
+
+  nName = strlen(zName);
+  nByte = sizeof(rbu_vfs) + nName + 1;
+  pNew = (rbu_vfs*)sqlite3_malloc64(nByte);
+  if( pNew==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_vfs *pParent;           /* Parent VFS */
+    memset(pNew, 0, nByte);
+    pParent = sqlite3_vfs_find(zParent);
+    if( pParent==0 ){
+      rc = SQLITE_NOTFOUND;
+    }else{
+      char *zSpace;
+      memcpy(&pNew->base, &vfs_template, sizeof(sqlite3_vfs));
+      pNew->base.mxPathname = pParent->mxPathname;
+      pNew->base.szOsFile = sizeof(rbu_file) + pParent->szOsFile;
+      pNew->pRealVfs = pParent;
+      pNew->base.zName = (const char*)(zSpace = (char*)&pNew[1]);
+      memcpy(zSpace, zName, nName);
+
+      /* Allocate the mutex and register the new VFS (not as the default) */
+      pNew->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_RECURSIVE);
+      if( pNew->mutex==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        rc = sqlite3_vfs_register(&pNew->base, 0);
+      }
+    }
+
+    if( rc!=SQLITE_OK ){
+      sqlite3_mutex_free(pNew->mutex);
+      sqlite3_free(pNew);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Configure the aggregate temp file size limit for this RBU handle.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_temp_size_limit(sqlite3rbu *pRbu, sqlite3_int64 n){
+  if( n>=0 ){
+    pRbu->szTempLimit = n;
+  }
+  return pRbu->szTempLimit;
+}
+
+SQLITE_API sqlite3_int64 sqlite3rbu_temp_size(sqlite3rbu *pRbu){
+  return pRbu->szTemp;
+}
+
+
+/**************************************************************************/
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_RBU) */
+
+/************** End of sqlite3rbu.c ******************************************/
+/************** Begin file dbstat.c ******************************************/
+/*
+** 2010 July 12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains an implementation of the "dbstat" virtual table.
+**
+** The dbstat virtual table is used to extract low-level storage
+** information from an SQLite database in order to implement the
+** "sqlite3_analyzer" utility.  See the ../tool/spaceanal.tcl script
+** for an example implementation.
+**
+** Additional information is available on the "dbstat.html" page of the
+** official SQLite documentation.
+*/
+
+/* #include "sqliteInt.h"   ** Requires access to internal data structures ** */
+#if (defined(SQLITE_ENABLE_DBSTAT_VTAB) || defined(SQLITE_TEST)) \
+    && !defined(SQLITE_OMIT_VIRTUALTABLE)
+
+/*
+** The pager and btree modules arrange objects in memory so that there are
+** always approximately 200 bytes of addressable memory following each page
+** buffer. This way small buffer overreads caused by corrupt database pages
+** do not cause undefined behaviour. This module pads each page buffer
+** by the following number of bytes for the same purpose.
+*/
+#define DBSTAT_PAGE_PADDING_BYTES 256
+
+/*
+** Page paths:
+**
+**   The value of the 'path' column describes the path taken from the
+**   root-node of the b-tree structure to each page. The value of the
+**   root-node path is '/'.
+**
+**   The value of the path for the left-most child page of the root of
+**   a b-tree is '/000/'. (Btrees store content ordered from left to right
+**   so the pages to the left have smaller keys than the pages to the right.)
+**   The next to left-most child of the root page is
+**   '/001', and so on, each sibling page identified by a 3-digit hex
+**   value. The children of the 451st left-most sibling have paths such
+**   as '/1c2/000/, '/1c2/001/' etc.
+**
+**   Overflow pages are specified by appending a '+' character and a
+**   six-digit hexadecimal value to the path to the cell they are linked
+**   from. For example, the three overflow pages in a chain linked from
+**   the left-most cell of the 450th child of the root page are identified
+**   by the paths:
+**
+**      '/1c2/000+000000'         // First page in overflow chain
+**      '/1c2/000+000001'         // Second page in overflow chain
+**      '/1c2/000+000002'         // Third page in overflow chain
+**
+**   If the paths are sorted using the BINARY collation sequence, then
+**   the overflow pages associated with a cell will appear earlier in the
+**   sort-order than its child page:
+**
+**      '/1c2/000/'               // Left-most child of 451st child of root
+*/
+static const char zDbstatSchema[] =
+  "CREATE TABLE x("
+  " name       TEXT,"          /*  0 Name of table or index */
+  " path       TEXT,"          /*  1 Path to page from root (NULL for agg) */
+  " pageno     INTEGER,"       /*  2 Page number (page count for aggregates) */
+  " pagetype   TEXT,"          /*  3 'internal', 'leaf', 'overflow', or NULL */
+  " ncell      INTEGER,"       /*  4 Cells on page (0 for overflow) */
+  " payload    INTEGER,"       /*  5 Bytes of payload on this page */
+  " unused     INTEGER,"       /*  6 Bytes of unused space on this page */
+  " mx_payload INTEGER,"       /*  7 Largest payload size of all cells */
+  " pgoffset   INTEGER,"       /*  8 Offset of page in file (NULL for agg) */
+  " pgsize     INTEGER,"       /*  9 Size of the page (sum for aggregate) */
+  " schema     TEXT HIDDEN,"   /* 10 Database schema being analyzed */
+  " aggregate  BOOLEAN HIDDEN" /* 11 aggregate info for each table */
+  ")"
+;
+
+/* Forward reference to data structured used in this module */
+typedef struct StatTable StatTable;
+typedef struct StatCursor StatCursor;
+typedef struct StatPage StatPage;
+typedef struct StatCell StatCell;
+
+/* Size information for a single cell within a btree page */
+struct StatCell {
+  int nLocal;                     /* Bytes of local payload */
+  u32 iChildPg;                   /* Child node (or 0 if this is a leaf) */
+  int nOvfl;                      /* Entries in aOvfl[] */
+  u32 *aOvfl;                     /* Array of overflow page numbers */
+  int nLastOvfl;                  /* Bytes of payload on final overflow page */
+  int iOvfl;                      /* Iterates through aOvfl[] */
+};
+
+/* Size information for a single btree page */
+struct StatPage {
+  u32 iPgno;                      /* Page number */
+  u8 *aPg;                        /* Page buffer from sqlite3_malloc() */
+  int iCell;                      /* Current cell */
+  char *zPath;                    /* Path to this page */
+
+  /* Variables populated by statDecodePage(): */
+  u8 flags;                       /* Copy of flags byte */
+  int nCell;                      /* Number of cells on page */
+  int nUnused;                    /* Number of unused bytes on page */
+  StatCell *aCell;                /* Array of parsed cells */
+  u32 iRightChildPg;              /* Right-child page number (or 0) */
+  int nMxPayload;                 /* Largest payload of any cell on the page */
+};
+
+/* The cursor for scanning the dbstat virtual table */
+struct StatCursor {
+  sqlite3_vtab_cursor base;       /* base class.  MUST BE FIRST! */
+  sqlite3_stmt *pStmt;            /* Iterates through set of root pages */
+  u8 isEof;                       /* After pStmt has returned SQLITE_DONE */
+  u8 isAgg;                       /* Aggregate results for each table */
+  int iDb;                        /* Schema used for this query */
+
+  StatPage aPage[32];             /* Pages in path to current page */
+  int iPage;                      /* Current entry in aPage[] */
+
+  /* Values to return. */
+  u32 iPageno;                    /* Value of 'pageno' column */
+  char *zName;                    /* Value of 'name' column */
+  char *zPath;                    /* Value of 'path' column */
+  char *zPagetype;                /* Value of 'pagetype' column */
+  int nPage;                      /* Number of pages in current btree */
+  int nCell;                      /* Value of 'ncell' column */
+  int nMxPayload;                 /* Value of 'mx_payload' column */
+  i64 nUnused;                    /* Value of 'unused' column */
+  i64 nPayload;                   /* Value of 'payload' column */
+  i64 iOffset;                    /* Value of 'pgOffset' column */
+  i64 szPage;                     /* Value of 'pgSize' column */
+};
+
+/* An instance of the DBSTAT virtual table */
+struct StatTable {
+  sqlite3_vtab base;              /* base class.  MUST BE FIRST! */
+  sqlite3 *db;                    /* Database connection that owns this vtab */
+  int iDb;                        /* Index of database to analyze */
+};
+
+#ifndef get2byte
+# define get2byte(x)   ((x)[0]<<8 | (x)[1])
+#endif
+
+/*
+** Connect to or create a new DBSTAT virtual table.
+*/
+static int statConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  StatTable *pTab = 0;
+  int rc = SQLITE_OK;
+  int iDb;
+  (void)pAux;
+
+  if( argc>=4 ){
+    Token nm;
+    sqlite3TokenInit(&nm, (char*)argv[3]);
+    iDb = sqlite3FindDb(db, &nm);
+    if( iDb<0 ){
+      *pzErr = sqlite3_mprintf("no such database: %s", argv[3]);
+      return SQLITE_ERROR;
+    }
+  }else{
+    iDb = 0;
+  }
+  sqlite3_vtab_config(db, SQLITE_VTAB_DIRECTONLY);
+  rc = sqlite3_declare_vtab(db, zDbstatSchema);
+  if( rc==SQLITE_OK ){
+    pTab = (StatTable *)sqlite3_malloc64(sizeof(StatTable));
+    if( pTab==0 ) rc = SQLITE_NOMEM_BKPT;
+  }
+
+  assert( rc==SQLITE_OK || pTab==0 );
+  if( rc==SQLITE_OK ){
+    memset(pTab, 0, sizeof(StatTable));
+    pTab->db = db;
+    pTab->iDb = iDb;
+  }
+
+  *ppVtab = (sqlite3_vtab*)pTab;
+  return rc;
+}
+
+/*
+** Disconnect from or destroy the DBSTAT virtual table.
+*/
+static int statDisconnect(sqlite3_vtab *pVtab){
+  sqlite3_free(pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** Compute the best query strategy and return the result in idxNum.
+**
+**   idxNum-Bit        Meaning
+**   ----------        ----------------------------------------------
+**      0x01           There is a schema=? term in the WHERE clause
+**      0x02           There is a name=? term in the WHERE clause
+**      0x04           There is an aggregate=? term in the WHERE clause
+**      0x08           Output should be ordered by name and path
+*/
+static int statBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  int i;
+  int iSchema = -1;
+  int iName = -1;
+  int iAgg = -1;
+  (void)tab;
+
+  /* Look for a valid schema=? constraint.  If found, change the idxNum to
+  ** 1 and request the value of that constraint be sent to xFilter.  And
+  ** lower the cost estimate to encourage the constrained version to be
+  ** used.
+  */
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    if( pIdxInfo->aConstraint[i].op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
+    if( pIdxInfo->aConstraint[i].usable==0 ){
+      /* Force DBSTAT table should always be the right-most table in a join */
+      return SQLITE_CONSTRAINT;
+    }
+    switch( pIdxInfo->aConstraint[i].iColumn ){
+      case 0: {    /* name */
+        iName = i;
+        break;
+      }
+      case 10: {   /* schema */
+        iSchema = i;
+        break;
+      }
+      case 11: {   /* aggregate */
+        iAgg = i;
+        break;
+      }
+    }
+  }
+  i = 0;
+  if( iSchema>=0 ){
+    pIdxInfo->aConstraintUsage[iSchema].argvIndex = ++i;
+    pIdxInfo->aConstraintUsage[iSchema].omit = 1;
+    pIdxInfo->idxNum |= 0x01;
+  }
+  if( iName>=0 ){
+    pIdxInfo->aConstraintUsage[iName].argvIndex = ++i;
+    pIdxInfo->idxNum |= 0x02;
+  }
+  if( iAgg>=0 ){
+    pIdxInfo->aConstraintUsage[iAgg].argvIndex = ++i;
+    pIdxInfo->idxNum |= 0x04;
+  }
+  pIdxInfo->estimatedCost = 1.0;
+
+  /* Records are always returned in ascending order of (name, path).
+  ** If this will satisfy the client, set the orderByConsumed flag so that
+  ** SQLite does not do an external sort.
+  */
+  if( ( pIdxInfo->nOrderBy==1
+     && pIdxInfo->aOrderBy[0].iColumn==0
+     && pIdxInfo->aOrderBy[0].desc==0
+     ) ||
+      ( pIdxInfo->nOrderBy==2
+     && pIdxInfo->aOrderBy[0].iColumn==0
+     && pIdxInfo->aOrderBy[0].desc==0
+     && pIdxInfo->aOrderBy[1].iColumn==1
+     && pIdxInfo->aOrderBy[1].desc==0
+     )
+  ){
+    pIdxInfo->orderByConsumed = 1;
+    pIdxInfo->idxNum |= 0x08;
+  }
+  pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_HEX;
+
+  return SQLITE_OK;
+}
+
+/*
+** Open a new DBSTAT cursor.
+*/
+static int statOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+  StatTable *pTab = (StatTable *)pVTab;
+  StatCursor *pCsr;
+
+  pCsr = (StatCursor *)sqlite3_malloc64(sizeof(StatCursor));
+  if( pCsr==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }else{
+    memset(pCsr, 0, sizeof(StatCursor));
+    pCsr->base.pVtab = pVTab;
+    pCsr->iDb = pTab->iDb;
+  }
+
+  *ppCursor = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+static void statClearCells(StatPage *p){
+  int i;
+  if( p->aCell ){
+    for(i=0; i<p->nCell; i++){
+      sqlite3_free(p->aCell[i].aOvfl);
+    }
+    sqlite3_free(p->aCell);
+  }
+  p->nCell = 0;
+  p->aCell = 0;
+}
+
+static void statClearPage(StatPage *p){
+  u8 *aPg = p->aPg;
+  statClearCells(p);
+  sqlite3_free(p->zPath);
+  memset(p, 0, sizeof(StatPage));
+  p->aPg = aPg;
+}
+
+static void statResetCsr(StatCursor *pCsr){
+  int i;
+  /* In some circumstances, specifically if an OOM has occurred, the call
+  ** to sqlite3_reset() may cause the pager to be reset (emptied). It is
+  ** important that statClearPage() is called to free any page refs before
+  ** this happens. dbsqlfuzz 9ed3e4e3816219d3509d711636c38542bf3f40b1. */
+  for(i=0; i<ArraySize(pCsr->aPage); i++){
+    statClearPage(&pCsr->aPage[i]);
+    sqlite3_free(pCsr->aPage[i].aPg);
+    pCsr->aPage[i].aPg = 0;
+  }
+  sqlite3_reset(pCsr->pStmt);
+  pCsr->iPage = 0;
+  sqlite3_free(pCsr->zPath);
+  pCsr->zPath = 0;
+  pCsr->isEof = 0;
+}
+
+/* Resize the space-used counters inside of the cursor */
+static void statResetCounts(StatCursor *pCsr){
+  pCsr->nCell = 0;
+  pCsr->nMxPayload = 0;
+  pCsr->nUnused = 0;
+  pCsr->nPayload = 0;
+  pCsr->szPage = 0;
+  pCsr->nPage = 0;
+}
+
+/*
+** Close a DBSTAT cursor.
+*/
+static int statClose(sqlite3_vtab_cursor *pCursor){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  statResetCsr(pCsr);
+  sqlite3_finalize(pCsr->pStmt);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** For a single cell on a btree page, compute the number of bytes of
+** content (payload) stored on that page.  That is to say, compute the
+** number of bytes of content not found on overflow pages.
+*/
+static int getLocalPayload(
+  int nUsable,                    /* Usable bytes per page */
+  u8 flags,                       /* Page flags */
+  int nTotal                      /* Total record (payload) size */
+){
+  int nLocal;
+  int nMinLocal;
+  int nMaxLocal;
+
+  if( flags==0x0D ){              /* Table leaf node */
+    nMinLocal = (nUsable - 12) * 32 / 255 - 23;
+    nMaxLocal = nUsable - 35;
+  }else{                          /* Index interior and leaf nodes */
+    nMinLocal = (nUsable - 12) * 32 / 255 - 23;
+    nMaxLocal = (nUsable - 12) * 64 / 255 - 23;
+  }
+
+  nLocal = nMinLocal + (nTotal - nMinLocal) % (nUsable - 4);
+  if( nLocal>nMaxLocal ) nLocal = nMinLocal;
+  return nLocal;
+}
+
+/* Populate the StatPage object with information about the all
+** cells found on the page currently under analysis.
+*/
+static int statDecodePage(Btree *pBt, StatPage *p){
+  int nUnused;
+  int iOff;
+  int nHdr;
+  int isLeaf;
+  int szPage;
+
+  u8 *aData = p->aPg;
+  u8 *aHdr = &aData[p->iPgno==1 ? 100 : 0];
+
+  p->flags = aHdr[0];
+  if( p->flags==0x0A || p->flags==0x0D ){
+    isLeaf = 1;
+    nHdr = 8;
+  }else if( p->flags==0x05 || p->flags==0x02 ){
+    isLeaf = 0;
+    nHdr = 12;
+  }else{
+    goto statPageIsCorrupt;
+  }
+  if( p->iPgno==1 ) nHdr += 100;
+  p->nCell = get2byte(&aHdr[3]);
+  p->nMxPayload = 0;
+  szPage = sqlite3BtreeGetPageSize(pBt);
+
+  nUnused = get2byte(&aHdr[5]) - nHdr - 2*p->nCell;
+  nUnused += (int)aHdr[7];
+  iOff = get2byte(&aHdr[1]);
+  while( iOff ){
+    int iNext;
+    if( iOff>=szPage ) goto statPageIsCorrupt;
+    nUnused += get2byte(&aData[iOff+2]);
+    iNext = get2byte(&aData[iOff]);
+    if( iNext<iOff+4 && iNext>0 ) goto statPageIsCorrupt;
+    iOff = iNext;
+  }
+  p->nUnused = nUnused;
+  p->iRightChildPg = isLeaf ? 0 : sqlite3Get4byte(&aHdr[8]);
+
+  if( p->nCell ){
+    int i;                        /* Used to iterate through cells */
+    int nUsable;                  /* Usable bytes per page */
+
+    sqlite3BtreeEnter(pBt);
+    nUsable = szPage - sqlite3BtreeGetReserveNoMutex(pBt);
+    sqlite3BtreeLeave(pBt);
+    p->aCell = sqlite3_malloc64((p->nCell+1) * sizeof(StatCell));
+    if( p->aCell==0 ) return SQLITE_NOMEM_BKPT;
+    memset(p->aCell, 0, (p->nCell+1) * sizeof(StatCell));
+
+    for(i=0; i<p->nCell; i++){
+      StatCell *pCell = &p->aCell[i];
+
+      iOff = get2byte(&aData[nHdr+i*2]);
+      if( iOff<nHdr || iOff>=szPage ) goto statPageIsCorrupt;
+      if( !isLeaf ){
+        pCell->iChildPg = sqlite3Get4byte(&aData[iOff]);
+        iOff += 4;
+      }
+      if( p->flags==0x05 ){
+        /* A table interior node. nPayload==0. */
+      }else{
+        u32 nPayload;             /* Bytes of payload total (local+overflow) */
+        int nLocal;               /* Bytes of payload stored locally */
+        iOff += getVarint32(&aData[iOff], nPayload);
+        if( p->flags==0x0D ){
+          u64 dummy;
+          iOff += sqlite3GetVarint(&aData[iOff], &dummy);
+        }
+        if( nPayload>(u32)p->nMxPayload ) p->nMxPayload = nPayload;
+        nLocal = getLocalPayload(nUsable, p->flags, nPayload);
+        if( nLocal<0 ) goto statPageIsCorrupt;
+        pCell->nLocal = nLocal;
+        assert( nPayload>=(u32)nLocal );
+        assert( nLocal<=(nUsable-35) );
+        if( nPayload>(u32)nLocal ){
+          int j;
+          int nOvfl = ((nPayload - nLocal) + nUsable-4 - 1) / (nUsable - 4);
+          if( iOff+nLocal+4>nUsable || nPayload>0x7fffffff ){
+            goto statPageIsCorrupt;
+          }
+          pCell->nLastOvfl = (nPayload-nLocal) - (nOvfl-1) * (nUsable-4);
+          pCell->nOvfl = nOvfl;
+          pCell->aOvfl = sqlite3_malloc64(sizeof(u32)*nOvfl);
+          if( pCell->aOvfl==0 ) return SQLITE_NOMEM_BKPT;
+          pCell->aOvfl[0] = sqlite3Get4byte(&aData[iOff+nLocal]);
+          for(j=1; j<nOvfl; j++){
+            int rc;
+            u32 iPrev = pCell->aOvfl[j-1];
+            DbPage *pPg = 0;
+            rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPrev, &pPg, 0);
+            if( rc!=SQLITE_OK ){
+              assert( pPg==0 );
+              return rc;
+            }
+            pCell->aOvfl[j] = sqlite3Get4byte(sqlite3PagerGetData(pPg));
+            sqlite3PagerUnref(pPg);
+          }
+        }
+      }
+    }
+  }
+
+  return SQLITE_OK;
+
+statPageIsCorrupt:
+  p->flags = 0;
+  statClearCells(p);
+  return SQLITE_OK;
+}
+
+/*
+** Populate the pCsr->iOffset and pCsr->szPage member variables. Based on
+** the current value of pCsr->iPageno.
+*/
+static void statSizeAndOffset(StatCursor *pCsr){
+  StatTable *pTab = (StatTable *)((sqlite3_vtab_cursor *)pCsr)->pVtab;
+  Btree *pBt = pTab->db->aDb[pTab->iDb].pBt;
+  Pager *pPager = sqlite3BtreePager(pBt);
+  sqlite3_file *fd;
+  sqlite3_int64 x[2];
+
+  /* If connected to a ZIPVFS backend, find the page size and
+  ** offset from ZIPVFS.
+  */
+  fd = sqlite3PagerFile(pPager);
+  x[0] = pCsr->iPageno;
+  if( sqlite3OsFileControl(fd, 230440, &x)==SQLITE_OK ){
+    pCsr->iOffset = x[0];
+    pCsr->szPage += x[1];
+  }else{
+    /* Not ZIPVFS: The default page size and offset */
+    pCsr->szPage += sqlite3BtreeGetPageSize(pBt);
+    pCsr->iOffset = (i64)pCsr->szPage * (pCsr->iPageno - 1);
+  }
+}
+
+/*
+** Load a copy of the page data for page iPg into the buffer belonging
+** to page object pPg. Allocate the buffer if necessary. Return SQLITE_OK
+** if successful, or an SQLite error code otherwise.
+*/
+static int statGetPage(
+  Btree *pBt,                     /* Load page from this b-tree */
+  u32 iPg,                        /* Page number to load */
+  StatPage *pPg                   /* Load page into this object */
+){
+  int pgsz = sqlite3BtreeGetPageSize(pBt);
+  DbPage *pDbPage = 0;
+  int rc;
+
+  if( pPg->aPg==0 ){
+    pPg->aPg = (u8*)sqlite3_malloc(pgsz + DBSTAT_PAGE_PADDING_BYTES);
+    if( pPg->aPg==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    memset(&pPg->aPg[pgsz], 0, DBSTAT_PAGE_PADDING_BYTES);
+  }
+
+  rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPg, &pDbPage, 0);
+  if( rc==SQLITE_OK ){
+    const u8 *a = sqlite3PagerGetData(pDbPage);
+    memcpy(pPg->aPg, a, pgsz);
+    sqlite3PagerUnref(pDbPage);
+  }
+
+  return rc;
+}
+
+/*
+** Move a DBSTAT cursor to the next entry.  Normally, the next
+** entry will be the next page, but in aggregated mode (pCsr->isAgg!=0),
+** the next entry is the next btree.
+*/
+static int statNext(sqlite3_vtab_cursor *pCursor){
+  int rc;
+  int nPayload;
+  char *z;
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  StatTable *pTab = (StatTable *)pCursor->pVtab;
+  Btree *pBt = pTab->db->aDb[pCsr->iDb].pBt;
+  Pager *pPager = sqlite3BtreePager(pBt);
+
+  sqlite3_free(pCsr->zPath);
+  pCsr->zPath = 0;
+
+statNextRestart:
+  if( pCsr->iPage<0 ){
+    /* Start measuring space on the next btree */
+    statResetCounts(pCsr);
+    rc = sqlite3_step(pCsr->pStmt);
+    if( rc==SQLITE_ROW ){
+      int nPage;
+      u32 iRoot = (u32)sqlite3_column_int64(pCsr->pStmt, 1);
+      sqlite3PagerPagecount(pPager, &nPage);
+      if( nPage==0 ){
+        pCsr->isEof = 1;
+        return sqlite3_reset(pCsr->pStmt);
+      }
+      rc = statGetPage(pBt, iRoot, &pCsr->aPage[0]);
+      pCsr->aPage[0].iPgno = iRoot;
+      pCsr->aPage[0].iCell = 0;
+      if( !pCsr->isAgg ){
+        pCsr->aPage[0].zPath = z = sqlite3_mprintf("/");
+        if( z==0 ) rc = SQLITE_NOMEM_BKPT;
+      }
+      pCsr->iPage = 0;
+      pCsr->nPage = 1;
+    }else{
+      pCsr->isEof = 1;
+      return sqlite3_reset(pCsr->pStmt);
+    }
+  }else{
+    /* Continue analyzing the btree previously started */
+    StatPage *p = &pCsr->aPage[pCsr->iPage];
+    if( !pCsr->isAgg ) statResetCounts(pCsr);
+    while( p->iCell<p->nCell ){
+      StatCell *pCell = &p->aCell[p->iCell];
+      while( pCell->iOvfl<pCell->nOvfl ){
+        int nUsable, iOvfl;
+        sqlite3BtreeEnter(pBt);
+        nUsable = sqlite3BtreeGetPageSize(pBt) -
+                        sqlite3BtreeGetReserveNoMutex(pBt);
+        sqlite3BtreeLeave(pBt);
+        pCsr->nPage++;
+        statSizeAndOffset(pCsr);
+        if( pCell->iOvfl<pCell->nOvfl-1 ){
+          pCsr->nPayload += nUsable - 4;
+        }else{
+          pCsr->nPayload += pCell->nLastOvfl;
+          pCsr->nUnused += nUsable - 4 - pCell->nLastOvfl;
+        }
+        iOvfl = pCell->iOvfl;
+        pCell->iOvfl++;
+        if( !pCsr->isAgg ){
+          pCsr->zName = (char *)sqlite3_column_text(pCsr->pStmt, 0);
+          pCsr->iPageno = pCell->aOvfl[iOvfl];
+          pCsr->zPagetype = "overflow";
+          pCsr->zPath = z = sqlite3_mprintf(
+              "%s%.3x+%.6x", p->zPath, p->iCell, iOvfl
+          );
+          return z==0 ? SQLITE_NOMEM_BKPT : SQLITE_OK;
+        }
+      }
+      if( p->iRightChildPg ) break;
+      p->iCell++;
+    }
+
+    if( !p->iRightChildPg || p->iCell>p->nCell ){
+      statClearPage(p);
+      pCsr->iPage--;
+      if( pCsr->isAgg && pCsr->iPage<0 ){
+        /* label-statNext-done:  When computing aggregate space usage over
+        ** an entire btree, this is the exit point from this function */
+        return SQLITE_OK;
+      }
+      goto statNextRestart; /* Tail recursion */
+    }
+    pCsr->iPage++;
+    if( pCsr->iPage>=ArraySize(pCsr->aPage) ){
+      statResetCsr(pCsr);
+      return SQLITE_CORRUPT_BKPT;
+    }
+    assert( p==&pCsr->aPage[pCsr->iPage-1] );
+
+    if( p->iCell==p->nCell ){
+      p[1].iPgno = p->iRightChildPg;
+    }else{
+      p[1].iPgno = p->aCell[p->iCell].iChildPg;
+    }
+    rc = statGetPage(pBt, p[1].iPgno, &p[1]);
+    pCsr->nPage++;
+    p[1].iCell = 0;
+    if( !pCsr->isAgg ){
+      p[1].zPath = z = sqlite3_mprintf("%s%.3x/", p->zPath, p->iCell);
+      if( z==0 ) rc = SQLITE_NOMEM_BKPT;
+    }
+    p->iCell++;
+  }
+
+
+  /* Populate the StatCursor fields with the values to be returned
+  ** by the xColumn() and xRowid() methods.
+  */
+  if( rc==SQLITE_OK ){
+    int i;
+    StatPage *p = &pCsr->aPage[pCsr->iPage];
+    pCsr->zName = (char *)sqlite3_column_text(pCsr->pStmt, 0);
+    pCsr->iPageno = p->iPgno;
+
+    rc = statDecodePage(pBt, p);
+    if( rc==SQLITE_OK ){
+      statSizeAndOffset(pCsr);
+
+      switch( p->flags ){
+        case 0x05:             /* table internal */
+        case 0x02:             /* index internal */
+          pCsr->zPagetype = "internal";
+          break;
+        case 0x0D:             /* table leaf */
+        case 0x0A:             /* index leaf */
+          pCsr->zPagetype = "leaf";
+          break;
+        default:
+          pCsr->zPagetype = "corrupted";
+          break;
+      }
+      pCsr->nCell += p->nCell;
+      pCsr->nUnused += p->nUnused;
+      if( p->nMxPayload>pCsr->nMxPayload ) pCsr->nMxPayload = p->nMxPayload;
+      if( !pCsr->isAgg ){
+        pCsr->zPath = z = sqlite3_mprintf("%s", p->zPath);
+        if( z==0 ) rc = SQLITE_NOMEM_BKPT;
+      }
+      nPayload = 0;
+      for(i=0; i<p->nCell; i++){
+        nPayload += p->aCell[i].nLocal;
+      }
+      pCsr->nPayload += nPayload;
+
+      /* If computing aggregate space usage by btree, continue with the
+      ** next page.  The loop will exit via the return at label-statNext-done
+      */
+      if( pCsr->isAgg ) goto statNextRestart;
+    }
+  }
+
+  return rc;
+}
+
+static int statEof(sqlite3_vtab_cursor *pCursor){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  return pCsr->isEof;
+}
+
+/* Initialize a cursor according to the query plan idxNum using the
+** arguments in argv[0].  See statBestIndex() for a description of the
+** meaning of the bits in idxNum.
+*/
+static int statFilter(
+  sqlite3_vtab_cursor *pCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  StatTable *pTab = (StatTable*)(pCursor->pVtab);
+  sqlite3_str *pSql;      /* Query of btrees to analyze */
+  char *zSql;             /* String value of pSql */
+  int iArg = 0;           /* Count of argv[] parameters used so far */
+  int rc = SQLITE_OK;     /* Result of this operation */
+  const char *zName = 0;  /* Only provide analysis of this table */
+  (void)argc;
+  (void)idxStr;
+
+  statResetCsr(pCsr);
+  sqlite3_finalize(pCsr->pStmt);
+  pCsr->pStmt = 0;
+  if( idxNum & 0x01 ){
+    /* schema=? constraint is present.  Get its value */
+    const char *zDbase = (const char*)sqlite3_value_text(argv[iArg++]);
+    pCsr->iDb = sqlite3FindDbName(pTab->db, zDbase);
+    if( pCsr->iDb<0 ){
+      pCsr->iDb = 0;
+      pCsr->isEof = 1;
+      return SQLITE_OK;
+    }
+  }else{
+    pCsr->iDb = pTab->iDb;
+  }
+  if( idxNum & 0x02 ){
+    /* name=? constraint is present */
+    zName = (const char*)sqlite3_value_text(argv[iArg++]);
+  }
+  if( idxNum & 0x04 ){
+    /* aggregate=? constraint is present */
+    pCsr->isAgg = sqlite3_value_double(argv[iArg++])!=0.0;
+  }else{
+    pCsr->isAgg = 0;
+  }
+  pSql = sqlite3_str_new(pTab->db);
+  sqlite3_str_appendf(pSql,
+      "SELECT * FROM ("
+        "SELECT 'sqlite_schema' AS name,1 AS rootpage,'table' AS type"
+        " UNION ALL "
+        "SELECT name,rootpage,type"
+        " FROM \"%w\".sqlite_schema WHERE rootpage!=0)",
+      pTab->db->aDb[pCsr->iDb].zDbSName);
+  if( zName ){
+    sqlite3_str_appendf(pSql, "WHERE name=%Q", zName);
+  }
+  if( idxNum & 0x08 ){
+    sqlite3_str_appendf(pSql, " ORDER BY name");
+  }
+  zSql = sqlite3_str_finish(pSql);
+  if( zSql==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }else{
+    rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pStmt, 0);
+    sqlite3_free(zSql);
+  }
+
+  if( rc==SQLITE_OK ){
+    pCsr->iPage = -1;
+    rc = statNext(pCursor);
+  }
+  return rc;
+}
+
+static int statColumn(
+  sqlite3_vtab_cursor *pCursor,
+  sqlite3_context *ctx,
+  int i
+){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  switch( i ){
+    case 0:            /* name */
+      sqlite3_result_text(ctx, pCsr->zName, -1, SQLITE_TRANSIENT);
+      break;
+    case 1:            /* path */
+      if( !pCsr->isAgg ){
+        sqlite3_result_text(ctx, pCsr->zPath, -1, SQLITE_TRANSIENT);
+      }
+      break;
+    case 2:            /* pageno */
+      if( pCsr->isAgg ){
+        sqlite3_result_int64(ctx, pCsr->nPage);
+      }else{
+        sqlite3_result_int64(ctx, pCsr->iPageno);
+      }
+      break;
+    case 3:            /* pagetype */
+      if( !pCsr->isAgg ){
+        sqlite3_result_text(ctx, pCsr->zPagetype, -1, SQLITE_STATIC);
+      }
+      break;
+    case 4:            /* ncell */
+      sqlite3_result_int64(ctx, pCsr->nCell);
+      break;
+    case 5:            /* payload */
+      sqlite3_result_int64(ctx, pCsr->nPayload);
+      break;
+    case 6:            /* unused */
+      sqlite3_result_int64(ctx, pCsr->nUnused);
+      break;
+    case 7:            /* mx_payload */
+      sqlite3_result_int64(ctx, pCsr->nMxPayload);
+      break;
+    case 8:            /* pgoffset */
+      if( !pCsr->isAgg ){
+        sqlite3_result_int64(ctx, pCsr->iOffset);
+      }
+      break;
+    case 9:            /* pgsize */
+      sqlite3_result_int64(ctx, pCsr->szPage);
+      break;
+    case 10: {         /* schema */
+      sqlite3 *db = sqlite3_context_db_handle(ctx);
+      int iDb = pCsr->iDb;
+      sqlite3_result_text(ctx, db->aDb[iDb].zDbSName, -1, SQLITE_STATIC);
+      break;
+    }
+    default: {         /* aggregate */
+      sqlite3_result_int(ctx, pCsr->isAgg);
+      break;
+    }
+  }
+  return SQLITE_OK;
+}
+
+static int statRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  *pRowid = pCsr->iPageno;
+  return SQLITE_OK;
+}
+
+/*
+** Invoke this routine to register the "dbstat" virtual table module
+*/
+SQLITE_PRIVATE int sqlite3DbstatRegister(sqlite3 *db){
+  static sqlite3_module dbstat_module = {
+    0,                            /* iVersion */
+    statConnect,                  /* xCreate */
+    statConnect,                  /* xConnect */
+    statBestIndex,                /* xBestIndex */
+    statDisconnect,               /* xDisconnect */
+    statDisconnect,               /* xDestroy */
+    statOpen,                     /* xOpen - open a cursor */
+    statClose,                    /* xClose - close a cursor */
+    statFilter,                   /* xFilter - configure scan constraints */
+    statNext,                     /* xNext - advance a cursor */
+    statEof,                      /* xEof - check for end of scan */
+    statColumn,                   /* xColumn - read data */
+    statRowid,                    /* xRowid - read data */
+    0,                            /* xUpdate */
+    0,                            /* xBegin */
+    0,                            /* xSync */
+    0,                            /* xCommit */
+    0,                            /* xRollback */
+    0,                            /* xFindMethod */
+    0,                            /* xRename */
+    0,                            /* xSavepoint */
+    0,                            /* xRelease */
+    0,                            /* xRollbackTo */
+    0,                            /* xShadowName */
+    0                             /* xIntegrity */
+  };
+  return sqlite3_create_module(db, "dbstat", &dbstat_module, 0);
+}
+#elif defined(SQLITE_ENABLE_DBSTAT_VTAB)
+SQLITE_PRIVATE int sqlite3DbstatRegister(sqlite3 *db){ return SQLITE_OK; }
+#endif /* SQLITE_ENABLE_DBSTAT_VTAB */
+
+/************** End of dbstat.c **********************************************/
+/************** Begin file dbpage.c ******************************************/
+/*
+** 2017-10-11
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains an implementation of the "sqlite_dbpage" virtual table.
+**
+** The sqlite_dbpage virtual table is used to read or write whole raw
+** pages of the database file.  The pager interface is used so that
+** uncommitted changes and changes recorded in the WAL file are correctly
+** retrieved.
+**
+** Usage example:
+**
+**    SELECT data FROM sqlite_dbpage('aux1') WHERE pgno=123;
+**
+** This is an eponymous virtual table so it does not need to be created before
+** use.  The optional argument to the sqlite_dbpage() table name is the
+** schema for the database file that is to be read.  The default schema is
+** "main".
+**
+** The data field of sqlite_dbpage table can be updated.  The new
+** value must be a BLOB which is the correct page size, otherwise the
+** update fails.  INSERT operations also work, and operate as if they
+** where REPLACE.  The size of the database can be extended by INSERT-ing
+** new pages on the end.
+**
+** Rows may not be deleted.  However, doing an INSERT to page number N
+** with NULL page data causes the N-th page and all subsequent pages to be
+** deleted and the database to be truncated.
+*/
+
+/* #include "sqliteInt.h"   ** Requires access to internal data structures ** */
+#if (defined(SQLITE_ENABLE_DBPAGE_VTAB) || defined(SQLITE_TEST)) \
+    && !defined(SQLITE_OMIT_VIRTUALTABLE)
+
+typedef struct DbpageTable DbpageTable;
+typedef struct DbpageCursor DbpageCursor;
+
+struct DbpageCursor {
+  sqlite3_vtab_cursor base;       /* Base class.  Must be first */
+  int pgno;                       /* Current page number */
+  int mxPgno;                     /* Last page to visit on this scan */
+  Pager *pPager;                  /* Pager being read/written */
+  DbPage *pPage1;                 /* Page 1 of the database */
+  int iDb;                        /* Index of database to analyze */
+  int szPage;                     /* Size of each page in bytes */
+};
+
+struct DbpageTable {
+  sqlite3_vtab base;              /* Base class.  Must be first */
+  sqlite3 *db;                    /* The database */
+  int iDbTrunc;                   /* Database to truncate */
+  Pgno pgnoTrunc;                 /* Size to truncate to */
+};
+
+/* Columns */
+#define DBPAGE_COLUMN_PGNO    0
+#define DBPAGE_COLUMN_DATA    1
+#define DBPAGE_COLUMN_SCHEMA  2
+
+
+/*
+** Connect to or create a dbpagevfs virtual table.
+*/
+static int dbpageConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  DbpageTable *pTab = 0;
+  int rc = SQLITE_OK;
+  (void)pAux;
+  (void)argc;
+  (void)argv;
+  (void)pzErr;
+
+  sqlite3_vtab_config(db, SQLITE_VTAB_DIRECTONLY);
+  sqlite3_vtab_config(db, SQLITE_VTAB_USES_ALL_SCHEMAS);
+  rc = sqlite3_declare_vtab(db,
+          "CREATE TABLE x(pgno INTEGER PRIMARY KEY, data BLOB, schema HIDDEN)");
+  if( rc==SQLITE_OK ){
+    pTab = (DbpageTable *)sqlite3_malloc64(sizeof(DbpageTable));
+    if( pTab==0 ) rc = SQLITE_NOMEM_BKPT;
+  }
+
+  assert( rc==SQLITE_OK || pTab==0 );
+  if( rc==SQLITE_OK ){
+    memset(pTab, 0, sizeof(DbpageTable));
+    pTab->db = db;
+  }
+
+  *ppVtab = (sqlite3_vtab*)pTab;
+  return rc;
+}
+
+/*
+** Disconnect from or destroy a dbpagevfs virtual table.
+*/
+static int dbpageDisconnect(sqlite3_vtab *pVtab){
+  sqlite3_free(pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** idxNum:
+**
+**     0     schema=main, full table scan
+**     1     schema=main, pgno=?1
+**     2     schema=?1, full table scan
+**     3     schema=?1, pgno=?2
+*/
+static int dbpageBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  int i;
+  int iPlan = 0;
+  (void)tab;
+
+  /* If there is a schema= constraint, it must be honored.  Report a
+  ** ridiculously large estimated cost if the schema= constraint is
+  ** unavailable
+  */
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[i];
+    if( p->iColumn!=DBPAGE_COLUMN_SCHEMA ) continue;
+    if( p->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
+    if( !p->usable ){
+      /* No solution. */
+      return SQLITE_CONSTRAINT;
+    }
+    iPlan = 2;
+    pIdxInfo->aConstraintUsage[i].argvIndex = 1;
+    pIdxInfo->aConstraintUsage[i].omit = 1;
+    break;
+  }
+
+  /* If we reach this point, it means that either there is no schema=
+  ** constraint (in which case we use the "main" schema) or else the
+  ** schema constraint was accepted.  Lower the estimated cost accordingly
+  */
+  pIdxInfo->estimatedCost = 1.0e6;
+
+  /* Check for constraints against pgno */
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[i];
+    if( p->usable && p->iColumn<=0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ ){
+      pIdxInfo->estimatedRows = 1;
+      pIdxInfo->idxFlags = SQLITE_INDEX_SCAN_UNIQUE;
+      pIdxInfo->estimatedCost = 1.0;
+      pIdxInfo->aConstraintUsage[i].argvIndex = iPlan ? 2 : 1;
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      iPlan |= 1;
+      break;
+    }
+  }
+  pIdxInfo->idxNum = iPlan;
+
+  if( pIdxInfo->nOrderBy>=1
+   && pIdxInfo->aOrderBy[0].iColumn<=0
+   && pIdxInfo->aOrderBy[0].desc==0
+  ){
+    pIdxInfo->orderByConsumed = 1;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Open a new dbpagevfs cursor.
+*/
+static int dbpageOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+  DbpageCursor *pCsr;
+
+  pCsr = (DbpageCursor *)sqlite3_malloc64(sizeof(DbpageCursor));
+  if( pCsr==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }else{
+    memset(pCsr, 0, sizeof(DbpageCursor));
+    pCsr->base.pVtab = pVTab;
+    pCsr->pgno = -1;
+  }
+
+  *ppCursor = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** Close a dbpagevfs cursor.
+*/
+static int dbpageClose(sqlite3_vtab_cursor *pCursor){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  if( pCsr->pPage1 ) sqlite3PagerUnrefPageOne(pCsr->pPage1);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** Move a dbpagevfs cursor to the next entry in the file.
+*/
+static int dbpageNext(sqlite3_vtab_cursor *pCursor){
+  int rc = SQLITE_OK;
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  pCsr->pgno++;
+  return rc;
+}
+
+static int dbpageEof(sqlite3_vtab_cursor *pCursor){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  return pCsr->pgno > pCsr->mxPgno;
+}
+
+/*
+** idxNum:
+**
+**     0     schema=main, full table scan
+**     1     schema=main, pgno=?1
+**     2     schema=?1, full table scan
+**     3     schema=?1, pgno=?2
+**
+** idxStr is not used
+*/
+static int dbpageFilter(
+  sqlite3_vtab_cursor *pCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  DbpageTable *pTab = (DbpageTable *)pCursor->pVtab;
+  int rc;
+  sqlite3 *db = pTab->db;
+  Btree *pBt;
+
+  (void)idxStr;
+
+  /* Default setting is no rows of result */
+  pCsr->pgno = 1;
+  pCsr->mxPgno = 0;
+
+  if( idxNum & 2 ){
+    const char *zSchema;
+    assert( argc>=1 );
+    zSchema = (const char*)sqlite3_value_text(argv[0]);
+    pCsr->iDb = sqlite3FindDbName(db, zSchema);
+    if( pCsr->iDb<0 ) return SQLITE_OK;
+  }else{
+    pCsr->iDb = 0;
+  }
+  pBt = db->aDb[pCsr->iDb].pBt;
+  if( NEVER(pBt==0) ) return SQLITE_OK;
+  pCsr->pPager = sqlite3BtreePager(pBt);
+  pCsr->szPage = sqlite3BtreeGetPageSize(pBt);
+  pCsr->mxPgno = sqlite3BtreeLastPage(pBt);
+  if( idxNum & 1 ){
+    assert( argc>(idxNum>>1) );
+    pCsr->pgno = sqlite3_value_int(argv[idxNum>>1]);
+    if( pCsr->pgno<1 || pCsr->pgno>pCsr->mxPgno ){
+      pCsr->pgno = 1;
+      pCsr->mxPgno = 0;
+    }else{
+      pCsr->mxPgno = pCsr->pgno;
+    }
+  }else{
+    assert( pCsr->pgno==1 );
+  }
+  if( pCsr->pPage1 ) sqlite3PagerUnrefPageOne(pCsr->pPage1);
+  rc = sqlite3PagerGet(pCsr->pPager, 1, &pCsr->pPage1, 0);
+  return rc;
+}
+
+static int dbpageColumn(
+  sqlite3_vtab_cursor *pCursor,
+  sqlite3_context *ctx,
+  int i
+){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  int rc = SQLITE_OK;
+  switch( i ){
+    case 0: {           /* pgno */
+      sqlite3_result_int(ctx, pCsr->pgno);
+      break;
+    }
+    case 1: {           /* data */
+      DbPage *pDbPage = 0;
+      if( pCsr->pgno==((PENDING_BYTE/pCsr->szPage)+1) ){
+        /* The pending byte page. Assume it is zeroed out. Attempting to
+        ** request this page from the page is an SQLITE_CORRUPT error. */
+        sqlite3_result_zeroblob(ctx, pCsr->szPage);
+      }else{
+        rc = sqlite3PagerGet(pCsr->pPager, pCsr->pgno, (DbPage**)&pDbPage, 0);
+        if( rc==SQLITE_OK ){
+          sqlite3_result_blob(ctx, sqlite3PagerGetData(pDbPage), pCsr->szPage,
+              SQLITE_TRANSIENT);
+        }
+        sqlite3PagerUnref(pDbPage);
+      }
+      break;
+    }
+    default: {          /* schema */
+      sqlite3 *db = sqlite3_context_db_handle(ctx);
+      sqlite3_result_text(ctx, db->aDb[pCsr->iDb].zDbSName, -1, SQLITE_STATIC);
+      break;
+    }
+  }
+  return rc;
+}
+
+static int dbpageRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  *pRowid = pCsr->pgno;
+  return SQLITE_OK;
+}
+
+/*
+** Open write transactions. Since we do not know in advance which database
+** files will be written by the sqlite_dbpage virtual table, start a write
+** transaction on them all.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise.
+*/
+static int dbpageBeginTrans(DbpageTable *pTab){
+  sqlite3 *db = pTab->db;
+  int rc = SQLITE_OK;
+  int i;
+  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ) rc = sqlite3BtreeBeginTrans(pBt, 1, 0);
+  }
+  return rc;
+}
+
+static int dbpageUpdate(
+  sqlite3_vtab *pVtab,
+  int argc,
+  sqlite3_value **argv,
+  sqlite_int64 *pRowid
+){
+  DbpageTable *pTab = (DbpageTable *)pVtab;
+  Pgno pgno;
+  DbPage *pDbPage = 0;
+  int rc = SQLITE_OK;
+  char *zErr = 0;
+  int iDb;
+  Btree *pBt;
+  Pager *pPager;
+  int szPage;
+  int isInsert;
+
+  (void)pRowid;
+  if( pTab->db->flags & SQLITE_Defensive ){
+    zErr = "read-only";
+    goto update_fail;
+  }
+  if( argc==1 ){
+    zErr = "cannot delete";
+    goto update_fail;
+  }
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
+    pgno = (Pgno)sqlite3_value_int(argv[2]);
+    isInsert = 1;
+  }else{
+    pgno = sqlite3_value_int(argv[0]);
+    if( (Pgno)sqlite3_value_int(argv[1])!=pgno ){
+      zErr = "cannot insert";
+      goto update_fail;
+    }
+    isInsert = 0;
+  }
+  if( sqlite3_value_type(argv[4])==SQLITE_NULL ){
+    iDb = 0;
+  }else{
+    const char *zSchema = (const char*)sqlite3_value_text(argv[4]);
+    iDb = sqlite3FindDbName(pTab->db, zSchema);
+    if( iDb<0 ){
+      zErr = "no such schema";
+      goto update_fail;
+    }
+  }
+  pBt = pTab->db->aDb[iDb].pBt;
+  if( pgno<1 || NEVER(pBt==0) ){
+    zErr = "bad page number";
+    goto update_fail;
+  }
+  szPage = sqlite3BtreeGetPageSize(pBt);
+  if( sqlite3_value_type(argv[3])!=SQLITE_BLOB
+   || sqlite3_value_bytes(argv[3])!=szPage
+  ){
+    if( sqlite3_value_type(argv[3])==SQLITE_NULL && isInsert && pgno>1 ){
+      /* "INSERT INTO dbpage($PGNO,NULL)" causes page number $PGNO and
+      ** all subsequent pages to be deleted. */
+      pTab->iDbTrunc = iDb;
+      pgno--;
+      pTab->pgnoTrunc = pgno;
+    }else{
+      zErr = "bad page value";
+      goto update_fail;
+    }
+  }
+
+  if( dbpageBeginTrans(pTab)!=SQLITE_OK ){
+    zErr = "failed to open transaction";
+    goto update_fail;
+  }
+
+  pPager = sqlite3BtreePager(pBt);
+  rc = sqlite3PagerGet(pPager, pgno, (DbPage**)&pDbPage, 0);
+  if( rc==SQLITE_OK ){
+    const void *pData = sqlite3_value_blob(argv[3]);
+    if( (rc = sqlite3PagerWrite(pDbPage))==SQLITE_OK && pData ){
+      unsigned char *aPage = sqlite3PagerGetData(pDbPage);
+      memcpy(aPage, pData, szPage);
+      pTab->pgnoTrunc = 0;
+    }
+  }else{
+    pTab->pgnoTrunc = 0;
+  }
+  sqlite3PagerUnref(pDbPage);
+  return rc;
+
+update_fail:
+  pTab->pgnoTrunc = 0;
+  sqlite3_free(pVtab->zErrMsg);
+  pVtab->zErrMsg = sqlite3_mprintf("%s", zErr);
+  return SQLITE_ERROR;
+}
+
+static int dbpageBegin(sqlite3_vtab *pVtab){
+  DbpageTable *pTab = (DbpageTable *)pVtab;
+  pTab->pgnoTrunc = 0;
+  return SQLITE_OK;
+}
+
+/* Invoke sqlite3PagerTruncate() as necessary, just prior to COMMIT
+*/
+static int dbpageSync(sqlite3_vtab *pVtab){
+  DbpageTable *pTab = (DbpageTable *)pVtab;
+  if( pTab->pgnoTrunc>0 ){
+    Btree *pBt = pTab->db->aDb[pTab->iDbTrunc].pBt;
+    Pager *pPager = sqlite3BtreePager(pBt);
+    sqlite3BtreeEnter(pBt);
+    if( pTab->pgnoTrunc<sqlite3BtreeLastPage(pBt) ){
+      sqlite3PagerTruncateImage(pPager, pTab->pgnoTrunc);
+    }
+    sqlite3BtreeLeave(pBt);
+  }
+  pTab->pgnoTrunc = 0;
+  return SQLITE_OK;
+}
+
+/* Cancel any pending truncate.
+*/
+static int dbpageRollbackTo(sqlite3_vtab *pVtab, int notUsed1){
+  DbpageTable *pTab = (DbpageTable *)pVtab;
+  pTab->pgnoTrunc = 0;
+  (void)notUsed1;
+  return SQLITE_OK;
+}
+
+/*
+** Invoke this routine to register the "dbpage" virtual table module
+*/
+SQLITE_PRIVATE int sqlite3DbpageRegister(sqlite3 *db){
+  static sqlite3_module dbpage_module = {
+    2,                            /* iVersion */
+    dbpageConnect,                /* xCreate */
+    dbpageConnect,                /* xConnect */
+    dbpageBestIndex,              /* xBestIndex */
+    dbpageDisconnect,             /* xDisconnect */
+    dbpageDisconnect,             /* xDestroy */
+    dbpageOpen,                   /* xOpen - open a cursor */
+    dbpageClose,                  /* xClose - close a cursor */
+    dbpageFilter,                 /* xFilter - configure scan constraints */
+    dbpageNext,                   /* xNext - advance a cursor */
+    dbpageEof,                    /* xEof - check for end of scan */
+    dbpageColumn,                 /* xColumn - read data */
+    dbpageRowid,                  /* xRowid - read data */
+    dbpageUpdate,                 /* xUpdate */
+    dbpageBegin,                  /* xBegin */
+    dbpageSync,                   /* xSync */
+    0,                            /* xCommit */
+    0,                            /* xRollback */
+    0,                            /* xFindMethod */
+    0,                            /* xRename */
+    0,                            /* xSavepoint */
+    0,                            /* xRelease */
+    dbpageRollbackTo,             /* xRollbackTo */
+    0,                            /* xShadowName */
+    0                             /* xIntegrity */
+  };
+  return sqlite3_create_module(db, "sqlite_dbpage", &dbpage_module, 0);
+}
+#elif defined(SQLITE_ENABLE_DBPAGE_VTAB)
+SQLITE_PRIVATE int sqlite3DbpageRegister(sqlite3 *db){ return SQLITE_OK; }
+#endif /* SQLITE_ENABLE_DBSTAT_VTAB */
+
+/************** End of dbpage.c **********************************************/
+/************** Begin file sqlite3session.c **********************************/
+
+#if defined(SQLITE_ENABLE_SESSION) && defined(SQLITE_ENABLE_PREUPDATE_HOOK)
+/* #include "sqlite3session.h" */
+/* #include <assert.h> */
+/* #include <string.h> */
+
+#ifndef SQLITE_AMALGAMATION
+/* # include "sqliteInt.h" */
+/* # include "vdbeInt.h" */
+#endif
+
+typedef struct SessionTable SessionTable;
+typedef struct SessionChange SessionChange;
+typedef struct SessionBuffer SessionBuffer;
+typedef struct SessionInput SessionInput;
+
+/*
+** Minimum chunk size used by streaming versions of functions.
+*/
+#ifndef SESSIONS_STRM_CHUNK_SIZE
+# ifdef SQLITE_TEST
+#   define SESSIONS_STRM_CHUNK_SIZE 64
+# else
+#   define SESSIONS_STRM_CHUNK_SIZE 1024
+# endif
+#endif
+
+#define SESSIONS_ROWID "_rowid_"
+
+static int sessions_strm_chunk_size = SESSIONS_STRM_CHUNK_SIZE;
+
+typedef struct SessionHook SessionHook;
+struct SessionHook {
+  void *pCtx;
+  int (*xOld)(void*,int,sqlite3_value**);
+  int (*xNew)(void*,int,sqlite3_value**);
+  int (*xCount)(void*);
+  int (*xDepth)(void*);
+};
+
+/*
+** Session handle structure.
+*/
+struct sqlite3_session {
+  sqlite3 *db;                    /* Database handle session is attached to */
+  char *zDb;                      /* Name of database session is attached to */
+  int bEnableSize;                /* True if changeset_size() enabled */
+  int bEnable;                    /* True if currently recording */
+  int bIndirect;                  /* True if all changes are indirect */
+  int bAutoAttach;                /* True to auto-attach tables */
+  int bImplicitPK;                /* True to handle tables with implicit PK */
+  int rc;                         /* Non-zero if an error has occurred */
+  void *pFilterCtx;               /* First argument to pass to xTableFilter */
+  int (*xTableFilter)(void *pCtx, const char *zTab);
+  i64 nMalloc;                    /* Number of bytes of data allocated */
+  i64 nMaxChangesetSize;
+  sqlite3_value *pZeroBlob;       /* Value containing X'' */
+  sqlite3_session *pNext;         /* Next session object on same db. */
+  SessionTable *pTable;           /* List of attached tables */
+  SessionHook hook;               /* APIs to grab new and old data with */
+};
+
+/*
+** Instances of this structure are used to build strings or binary records.
+*/
+struct SessionBuffer {
+  u8 *aBuf;                       /* Pointer to changeset buffer */
+  int nBuf;                       /* Size of buffer aBuf */
+  int nAlloc;                     /* Size of allocation containing aBuf */
+};
+
+/*
+** An object of this type is used internally as an abstraction for
+** input data. Input data may be supplied either as a single large buffer
+** (e.g. sqlite3changeset_start()) or using a stream function (e.g.
+**  sqlite3changeset_start_strm()).
+**
+** bNoDiscard:
+**   If true, then the only time data is discarded is as a result of explicit
+**   sessionDiscardData() calls. Not within every sessionInputBuffer() call.
+*/
+struct SessionInput {
+  int bNoDiscard;                 /* If true, do not discard in InputBuffer() */
+  int iCurrent;                   /* Offset in aData[] of current change */
+  int iNext;                      /* Offset in aData[] of next change */
+  u8 *aData;                      /* Pointer to buffer containing changeset */
+  int nData;                      /* Number of bytes in aData */
+
+  SessionBuffer buf;              /* Current read buffer */
+  int (*xInput)(void*, void*, int*);        /* Input stream call (or NULL) */
+  void *pIn;                                /* First argument to xInput */
+  int bEof;                       /* Set to true after xInput finished */
+};
+
+/*
+** Structure for changeset iterators.
+*/
+struct sqlite3_changeset_iter {
+  SessionInput in;                /* Input buffer or stream */
+  SessionBuffer tblhdr;           /* Buffer to hold apValue/zTab/abPK/ */
+  int bPatchset;                  /* True if this is a patchset */
+  int bInvert;                    /* True to invert changeset */
+  int bSkipEmpty;                 /* Skip noop UPDATE changes */
+  int rc;                         /* Iterator error code */
+  sqlite3_stmt *pConflict;        /* Points to conflicting row, if any */
+  char *zTab;                     /* Current table */
+  int nCol;                       /* Number of columns in zTab */
+  int op;                         /* Current operation */
+  int bIndirect;                  /* True if current change was indirect */
+  u8 *abPK;                       /* Primary key array */
+  sqlite3_value **apValue;        /* old.* and new.* values */
+};
+
+/*
+** Each session object maintains a set of the following structures, one
+** for each table the session object is monitoring. The structures are
+** stored in a linked list starting at sqlite3_session.pTable.
+**
+** The keys of the SessionTable.aChange[] hash table are all rows that have
+** been modified in any way since the session object was attached to the
+** table.
+**
+** The data associated with each hash-table entry is a structure containing
+** a subset of the initial values that the modified row contained at the
+** start of the session. Or no initial values if the row was inserted.
+**
+** pDfltStmt:
+**   This is only used by the sqlite3changegroup_xxx() APIs, not by
+**   regular sqlite3_session objects. It is a SELECT statement that
+**   selects the default value for each table column. For example,
+**   if the table is
+**
+**      CREATE TABLE xx(a DEFAULT 1, b, c DEFAULT 'abc')
+**
+**   then this variable is the compiled version of:
+**
+**      SELECT 1, NULL, 'abc'
+*/
+struct SessionTable {
+  SessionTable *pNext;
+  char *zName;                    /* Local name of table */
+  int nCol;                       /* Number of non-hidden columns */
+  int nTotalCol;                  /* Number of columns including hidden */
+  int bStat1;                     /* True if this is sqlite_stat1 */
+  int bRowid;                     /* True if this table uses rowid for PK */
+  const char **azCol;             /* Column names */
+  const char **azDflt;            /* Default value expressions */
+  int *aiIdx;                     /* Index to pass to xNew/xOld */
+  u8 *abPK;                       /* Array of primary key flags */
+  int nEntry;                     /* Total number of entries in hash table */
+  int nChange;                    /* Size of apChange[] array */
+  SessionChange **apChange;       /* Hash table buckets */
+  sqlite3_stmt *pDfltStmt;
+};
+
+/*
+** RECORD FORMAT:
+**
+** The following record format is similar to (but not compatible with) that
+** used in SQLite database files. This format is used as part of the
+** change-set binary format, and so must be architecture independent.
+**
+** Unlike the SQLite database record format, each field is self-contained -
+** there is no separation of header and data. Each field begins with a
+** single byte describing its type, as follows:
+**
+**       0x00: Undefined value.
+**       0x01: Integer value.
+**       0x02: Real value.
+**       0x03: Text value.
+**       0x04: Blob value.
+**       0x05: SQL NULL value.
+**
+** Note that the above match the definitions of SQLITE_INTEGER, SQLITE_TEXT
+** and so on in sqlite3.h. For undefined and NULL values, the field consists
+** only of the single type byte. For other types of values, the type byte
+** is followed by:
+**
+**   Text values:
+**     A varint containing the number of bytes in the value (encoded using
+**     UTF-8). Followed by a buffer containing the UTF-8 representation
+**     of the text value. There is no nul terminator.
+**
+**   Blob values:
+**     A varint containing the number of bytes in the value, followed by
+**     a buffer containing the value itself.
+**
+**   Integer values:
+**     An 8-byte big-endian integer value.
+**
+**   Real values:
+**     An 8-byte big-endian IEEE 754-2008 real value.
+**
+** Varint values are encoded in the same way as varints in the SQLite
+** record format.
+**
+** CHANGESET FORMAT:
+**
+** A changeset is a collection of DELETE, UPDATE and INSERT operations on
+** one or more tables. Operations on a single table are grouped together,
+** but may occur in any order (i.e. deletes, updates and inserts are all
+** mixed together).
+**
+** Each group of changes begins with a table header:
+**
+**   1 byte: Constant 0x54 (capital 'T')
+**   Varint: Number of columns in the table.
+**   nCol bytes: 0x01 for PK columns, 0x00 otherwise.
+**   N bytes: Unqualified table name (encoded using UTF-8). Nul-terminated.
+**
+** Followed by one or more changes to the table.
+**
+**   1 byte: Either SQLITE_INSERT (0x12), UPDATE (0x17) or DELETE (0x09).
+**   1 byte: The "indirect-change" flag.
+**   old.* record: (delete and update only)
+**   new.* record: (insert and update only)
+**
+** The "old.*" and "new.*" records, if present, are N field records in the
+** format described above under "RECORD FORMAT", where N is the number of
+** columns in the table. The i'th field of each record is associated with
+** the i'th column of the table, counting from left to right in the order
+** in which columns were declared in the CREATE TABLE statement.
+**
+** The new.* record that is part of each INSERT change contains the values
+** that make up the new row. Similarly, the old.* record that is part of each
+** DELETE change contains the values that made up the row that was deleted
+** from the database. In the changeset format, the records that are part
+** of INSERT or DELETE changes never contain any undefined (type byte 0x00)
+** fields.
+**
+** Within the old.* record associated with an UPDATE change, all fields
+** associated with table columns that are not PRIMARY KEY columns and are
+** not modified by the UPDATE change are set to "undefined". Other fields
+** are set to the values that made up the row before the UPDATE that the
+** change records took place. Within the new.* record, fields associated
+** with table columns modified by the UPDATE change contain the new
+** values. Fields associated with table columns that are not modified
+** are set to "undefined".
+**
+** PATCHSET FORMAT:
+**
+** A patchset is also a collection of changes. It is similar to a changeset,
+** but leaves undefined those fields that are not useful if no conflict
+** resolution is required when applying the changeset.
+**
+** Each group of changes begins with a table header:
+**
+**   1 byte: Constant 0x50 (capital 'P')
+**   Varint: Number of columns in the table.
+**   nCol bytes: 0x01 for PK columns, 0x00 otherwise.
+**   N bytes: Unqualified table name (encoded using UTF-8). Nul-terminated.
+**
+** Followed by one or more changes to the table.
+**
+**   1 byte: Either SQLITE_INSERT (0x12), UPDATE (0x17) or DELETE (0x09).
+**   1 byte: The "indirect-change" flag.
+**   single record: (PK fields for DELETE, PK and modified fields for UPDATE,
+**                   full record for INSERT).
+**
+** As in the changeset format, each field of the single record that is part
+** of a patchset change is associated with the correspondingly positioned
+** table column, counting from left to right within the CREATE TABLE
+** statement.
+**
+** For a DELETE change, all fields within the record except those associated
+** with PRIMARY KEY columns are omitted. The PRIMARY KEY fields contain the
+** values identifying the row to delete.
+**
+** For an UPDATE change, all fields except those associated with PRIMARY KEY
+** columns and columns that are modified by the UPDATE are set to "undefined".
+** PRIMARY KEY fields contain the values identifying the table row to update,
+** and fields associated with modified columns contain the new column values.
+**
+** The records associated with INSERT changes are in the same format as for
+** changesets. It is not possible for a record associated with an INSERT
+** change to contain a field set to "undefined".
+**
+** REBASE BLOB FORMAT:
+**
+** A rebase blob may be output by sqlite3changeset_apply_v2() and its
+** streaming equivalent for use with the sqlite3_rebaser APIs to rebase
+** existing changesets. A rebase blob contains one entry for each conflict
+** resolved using either the OMIT or REPLACE strategies within the apply_v2()
+** call.
+**
+** The format used for a rebase blob is very similar to that used for
+** changesets. All entries related to a single table are grouped together.
+**
+** Each group of entries begins with a table header in changeset format:
+**
+**   1 byte: Constant 0x54 (capital 'T')
+**   Varint: Number of columns in the table.
+**   nCol bytes: 0x01 for PK columns, 0x00 otherwise.
+**   N bytes: Unqualified table name (encoded using UTF-8). Nul-terminated.
+**
+** Followed by one or more entries associated with the table.
+**
+**   1 byte: Either SQLITE_INSERT (0x12), DELETE (0x09).
+**   1 byte: Flag. 0x01 for REPLACE, 0x00 for OMIT.
+**   record: (in the record format defined above).
+**
+** In a rebase blob, the first field is set to SQLITE_INSERT if the change
+** that caused the conflict was an INSERT or UPDATE, or to SQLITE_DELETE if
+** it was a DELETE. The second field is set to 0x01 if the conflict
+** resolution strategy was REPLACE, or 0x00 if it was OMIT.
+**
+** If the change that caused the conflict was a DELETE, then the single
+** record is a copy of the old.* record from the original changeset. If it
+** was an INSERT, then the single record is a copy of the new.* record. If
+** the conflicting change was an UPDATE, then the single record is a copy
+** of the new.* record with the PK fields filled in based on the original
+** old.* record.
+*/
+
+/*
+** For each row modified during a session, there exists a single instance of
+** this structure stored in a SessionTable.aChange[] hash table.
+*/
+struct SessionChange {
+  u8 op;                          /* One of UPDATE, DELETE, INSERT */
+  u8 bIndirect;                   /* True if this change is "indirect" */
+  u16 nRecordField;               /* Number of fields in aRecord[] */
+  int nMaxSize;                   /* Max size of eventual changeset record */
+  int nRecord;                    /* Number of bytes in buffer aRecord[] */
+  u8 *aRecord;                    /* Buffer containing old.* record */
+  SessionChange *pNext;           /* For hash-table collisions */
+};
+
+/*
+** Write a varint with value iVal into the buffer at aBuf. Return the
+** number of bytes written.
+*/
+static int sessionVarintPut(u8 *aBuf, int iVal){
+  return putVarint32(aBuf, iVal);
+}
+
+/*
+** Return the number of bytes required to store value iVal as a varint.
+*/
+static int sessionVarintLen(int iVal){
+  return sqlite3VarintLen(iVal);
+}
+
+/*
+** Read a varint value from aBuf[] into *piVal. Return the number of
+** bytes read.
+*/
+static int sessionVarintGet(const u8 *aBuf, int *piVal){
+  return getVarint32(aBuf, *piVal);
+}
+
+/* Load an unaligned and unsigned 32-bit integer */
+#define SESSION_UINT32(x) (((u32)(x)[0]<<24)|((x)[1]<<16)|((x)[2]<<8)|(x)[3])
+
+/*
+** Read a 64-bit big-endian integer value from buffer aRec[]. Return
+** the value read.
+*/
+static sqlite3_int64 sessionGetI64(u8 *aRec){
+  u64 x = SESSION_UINT32(aRec);
+  u32 y = SESSION_UINT32(aRec+4);
+  x = (x<<32) + y;
+  return (sqlite3_int64)x;
+}
+
+/*
+** Write a 64-bit big-endian integer value to the buffer aBuf[].
+*/
+static void sessionPutI64(u8 *aBuf, sqlite3_int64 i){
+  aBuf[0] = (i>>56) & 0xFF;
+  aBuf[1] = (i>>48) & 0xFF;
+  aBuf[2] = (i>>40) & 0xFF;
+  aBuf[3] = (i>>32) & 0xFF;
+  aBuf[4] = (i>>24) & 0xFF;
+  aBuf[5] = (i>>16) & 0xFF;
+  aBuf[6] = (i>> 8) & 0xFF;
+  aBuf[7] = (i>> 0) & 0xFF;
+}
+
+/*
+** This function is used to serialize the contents of value pValue (see
+** comment titled "RECORD FORMAT" above).
+**
+** If it is non-NULL, the serialized form of the value is written to
+** buffer aBuf. *pnWrite is set to the number of bytes written before
+** returning. Or, if aBuf is NULL, the only thing this function does is
+** set *pnWrite.
+**
+** If no error occurs, SQLITE_OK is returned. Or, if an OOM error occurs
+** within a call to sqlite3_value_text() (may fail if the db is utf-16))
+** SQLITE_NOMEM is returned.
+*/
+static int sessionSerializeValue(
+  u8 *aBuf,                       /* If non-NULL, write serialized value here */
+  sqlite3_value *pValue,          /* Value to serialize */
+  sqlite3_int64 *pnWrite          /* IN/OUT: Increment by bytes written */
+){
+  int nByte;                      /* Size of serialized value in bytes */
+
+  if( pValue ){
+    int eType;                    /* Value type (SQLITE_NULL, TEXT etc.) */
+
+    eType = sqlite3_value_type(pValue);
+    if( aBuf ) aBuf[0] = eType;
+
+    switch( eType ){
+      case SQLITE_NULL:
+        nByte = 1;
+        break;
+
+      case SQLITE_INTEGER:
+      case SQLITE_FLOAT:
+        if( aBuf ){
+          /* TODO: SQLite does something special to deal with mixed-endian
+          ** floating point values (e.g. ARM7). This code probably should
+          ** too.  */
+          u64 i;
+          if( eType==SQLITE_INTEGER ){
+            i = (u64)sqlite3_value_int64(pValue);
+          }else{
+            double r;
+            assert( sizeof(double)==8 && sizeof(u64)==8 );
+            r = sqlite3_value_double(pValue);
+            memcpy(&i, &r, 8);
+          }
+          sessionPutI64(&aBuf[1], i);
+        }
+        nByte = 9;
+        break;
+
+      default: {
+        u8 *z;
+        int n;
+        int nVarint;
+
+        assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
+        if( eType==SQLITE_TEXT ){
+          z = (u8 *)sqlite3_value_text(pValue);
+        }else{
+          z = (u8 *)sqlite3_value_blob(pValue);
+        }
+        n = sqlite3_value_bytes(pValue);
+        if( z==0 && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM;
+        nVarint = sessionVarintLen(n);
+
+        if( aBuf ){
+          sessionVarintPut(&aBuf[1], n);
+          if( n>0 ) memcpy(&aBuf[nVarint + 1], z, n);
+        }
+
+        nByte = 1 + nVarint + n;
+        break;
+      }
+    }
+  }else{
+    nByte = 1;
+    if( aBuf ) aBuf[0] = '\0';
+  }
+
+  if( pnWrite ) *pnWrite += nByte;
+  return SQLITE_OK;
+}
+
+/*
+** Allocate and return a pointer to a buffer nByte bytes in size. If
+** pSession is not NULL, increase the sqlite3_session.nMalloc variable
+** by the number of bytes allocated.
+*/
+static void *sessionMalloc64(sqlite3_session *pSession, i64 nByte){
+  void *pRet = sqlite3_malloc64(nByte);
+  if( pSession ) pSession->nMalloc += sqlite3_msize(pRet);
+  return pRet;
+}
+
+/*
+** Free buffer pFree, which must have been allocated by an earlier
+** call to sessionMalloc64(). If pSession is not NULL, decrease the
+** sqlite3_session.nMalloc counter by the number of bytes freed.
+*/
+static void sessionFree(sqlite3_session *pSession, void *pFree){
+  if( pSession ) pSession->nMalloc -= sqlite3_msize(pFree);
+  sqlite3_free(pFree);
+}
+
+/*
+** This macro is used to calculate hash key values for data structures. In
+** order to use this macro, the entire data structure must be represented
+** as a series of unsigned integers. In order to calculate a hash-key value
+** for a data structure represented as three such integers, the macro may
+** then be used as follows:
+**
+**    int hash_key_value;
+**    hash_key_value = HASH_APPEND(0, <value 1>);
+**    hash_key_value = HASH_APPEND(hash_key_value, <value 2>);
+**    hash_key_value = HASH_APPEND(hash_key_value, <value 3>);
+**
+** In practice, the data structures this macro is used for are the primary
+** key values of modified rows.
+*/
+#define HASH_APPEND(hash, add) ((hash) << 3) ^ (hash) ^ (unsigned int)(add)
+
+/*
+** Append the hash of the 64-bit integer passed as the second argument to the
+** hash-key value passed as the first. Return the new hash-key value.
+*/
+static unsigned int sessionHashAppendI64(unsigned int h, i64 i){
+  h = HASH_APPEND(h, i & 0xFFFFFFFF);
+  return HASH_APPEND(h, (i>>32)&0xFFFFFFFF);
+}
+
+/*
+** Append the hash of the blob passed via the second and third arguments to
+** the hash-key value passed as the first. Return the new hash-key value.
+*/
+static unsigned int sessionHashAppendBlob(unsigned int h, int n, const u8 *z){
+  int i;
+  for(i=0; i<n; i++) h = HASH_APPEND(h, z[i]);
+  return h;
+}
+
+/*
+** Append the hash of the data type passed as the second argument to the
+** hash-key value passed as the first. Return the new hash-key value.
+*/
+static unsigned int sessionHashAppendType(unsigned int h, int eType){
+  return HASH_APPEND(h, eType);
+}
+
+/*
+** This function may only be called from within a pre-update callback.
+** It calculates a hash based on the primary key values of the old.* or
+** new.* row currently available and, assuming no error occurs, writes it to
+** *piHash before returning. If the primary key contains one or more NULL
+** values, *pbNullPK is set to true before returning.
+**
+** If an error occurs, an SQLite error code is returned and the final values
+** of *piHash asn *pbNullPK are undefined. Otherwise, SQLITE_OK is returned
+** and the output variables are set as described above.
+*/
+static int sessionPreupdateHash(
+  sqlite3_session *pSession,      /* Session object that owns pTab */
+  i64 iRowid,
+  SessionTable *pTab,             /* Session table handle */
+  int bNew,                       /* True to hash the new.* PK */
+  int *piHash,                    /* OUT: Hash value */
+  int *pbNullPK                   /* OUT: True if there are NULL values in PK */
+){
+  unsigned int h = 0;             /* Hash value to return */
+  int i;                          /* Used to iterate through columns */
+
+  assert( pTab->nTotalCol==pSession->hook.xCount(pSession->hook.pCtx) );
+  if( pTab->bRowid ){
+    h = sessionHashAppendI64(h, iRowid);
+  }else{
+    assert( *pbNullPK==0 );
+    for(i=0; i<pTab->nCol; i++){
+      if( pTab->abPK[i] ){
+        int rc;
+        int eType;
+        sqlite3_value *pVal;
+        int iIdx = pTab->aiIdx[i];
+
+        if( bNew ){
+          rc = pSession->hook.xNew(pSession->hook.pCtx, iIdx, &pVal);
+        }else{
+          rc = pSession->hook.xOld(pSession->hook.pCtx, iIdx, &pVal);
+        }
+        if( rc!=SQLITE_OK ) return rc;
+
+        eType = sqlite3_value_type(pVal);
+        h = sessionHashAppendType(h, eType);
+        if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+          i64 iVal;
+          if( eType==SQLITE_INTEGER ){
+            iVal = sqlite3_value_int64(pVal);
+          }else{
+            double rVal = sqlite3_value_double(pVal);
+            assert( sizeof(iVal)==8 && sizeof(rVal)==8 );
+            memcpy(&iVal, &rVal, 8);
+          }
+          h = sessionHashAppendI64(h, iVal);
+        }else if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
+          const u8 *z;
+          int n;
+          if( eType==SQLITE_TEXT ){
+            z = (const u8 *)sqlite3_value_text(pVal);
+          }else{
+            z = (const u8 *)sqlite3_value_blob(pVal);
+          }
+          n = sqlite3_value_bytes(pVal);
+          if( !z && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM;
+          h = sessionHashAppendBlob(h, n, z);
+        }else{
+          assert( eType==SQLITE_NULL );
+          assert( pTab->bStat1==0 || i!=1 );
+          *pbNullPK = 1;
+        }
+      }
+    }
+  }
+
+  *piHash = (h % pTab->nChange);
+  return SQLITE_OK;
+}
+
+/*
+** The buffer that the argument points to contains a serialized SQL value.
+** Return the number of bytes of space occupied by the value (including
+** the type byte).
+*/
+static int sessionSerialLen(const u8 *a){
+  int e;
+  int n;
+  assert( a!=0 );
+  e = *a;
+  if( e==0 || e==0xFF ) return 1;
+  if( e==SQLITE_NULL ) return 1;
+  if( e==SQLITE_INTEGER || e==SQLITE_FLOAT ) return 9;
+  return sessionVarintGet(&a[1], &n) + 1 + n;
+}
+
+/*
+** Based on the primary key values stored in change aRecord, calculate a
+** hash key. Assume the has table has nBucket buckets. The hash keys
+** calculated by this function are compatible with those calculated by
+** sessionPreupdateHash().
+**
+** The bPkOnly argument is non-zero if the record at aRecord[] is from
+** a patchset DELETE. In this case the non-PK fields are omitted entirely.
+*/
+static unsigned int sessionChangeHash(
+  SessionTable *pTab,             /* Table handle */
+  int bPkOnly,                    /* Record consists of PK fields only */
+  u8 *aRecord,                    /* Change record */
+  int nBucket                     /* Assume this many buckets in hash table */
+){
+  unsigned int h = 0;             /* Value to return */
+  int i;                          /* Used to iterate through columns */
+  u8 *a = aRecord;                /* Used to iterate through change record */
+
+  for(i=0; i<pTab->nCol; i++){
+    int eType = *a;
+    int isPK = pTab->abPK[i];
+    if( bPkOnly && isPK==0 ) continue;
+
+    /* It is not possible for eType to be SQLITE_NULL here. The session
+    ** module does not record changes for rows with NULL values stored in
+    ** primary key columns. */
+    assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT
+         || eType==SQLITE_TEXT || eType==SQLITE_BLOB
+         || eType==SQLITE_NULL || eType==0
+    );
+    assert( !isPK || (eType!=0 && eType!=SQLITE_NULL) );
+
+    if( isPK ){
+      a++;
+      h = sessionHashAppendType(h, eType);
+      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+        h = sessionHashAppendI64(h, sessionGetI64(a));
+        a += 8;
+      }else{
+        int n;
+        a += sessionVarintGet(a, &n);
+        h = sessionHashAppendBlob(h, n, a);
+        a += n;
+      }
+    }else{
+      a += sessionSerialLen(a);
+    }
+  }
+  return (h % nBucket);
+}
+
+/*
+** Arguments aLeft and aRight are pointers to change records for table pTab.
+** This function returns true if the two records apply to the same row (i.e.
+** have the same values stored in the primary key columns), or false
+** otherwise.
+*/
+static int sessionChangeEqual(
+  SessionTable *pTab,             /* Table used for PK definition */
+  int bLeftPkOnly,                /* True if aLeft[] contains PK fields only */
+  u8 *aLeft,                      /* Change record */
+  int bRightPkOnly,               /* True if aRight[] contains PK fields only */
+  u8 *aRight                      /* Change record */
+){
+  u8 *a1 = aLeft;                 /* Cursor to iterate through aLeft */
+  u8 *a2 = aRight;                /* Cursor to iterate through aRight */
+  int iCol;                       /* Used to iterate through table columns */
+
+  for(iCol=0; iCol<pTab->nCol; iCol++){
+    if( pTab->abPK[iCol] ){
+      int n1 = sessionSerialLen(a1);
+      int n2 = sessionSerialLen(a2);
+
+      if( n1!=n2 || memcmp(a1, a2, n1) ){
+        return 0;
+      }
+      a1 += n1;
+      a2 += n2;
+    }else{
+      if( bLeftPkOnly==0 ) a1 += sessionSerialLen(a1);
+      if( bRightPkOnly==0 ) a2 += sessionSerialLen(a2);
+    }
+  }
+
+  return 1;
+}
+
+/*
+** Arguments aLeft and aRight both point to buffers containing change
+** records with nCol columns. This function "merges" the two records into
+** a single records which is written to the buffer at *paOut. *paOut is
+** then set to point to one byte after the last byte written before
+** returning.
+**
+** The merging of records is done as follows: For each column, if the
+** aRight record contains a value for the column, copy the value from
+** their. Otherwise, if aLeft contains a value, copy it. If neither
+** record contains a value for a given column, then neither does the
+** output record.
+*/
+static void sessionMergeRecord(
+  u8 **paOut,
+  int nCol,
+  u8 *aLeft,
+  u8 *aRight
+){
+  u8 *a1 = aLeft;                 /* Cursor used to iterate through aLeft */
+  u8 *a2 = aRight;                /* Cursor used to iterate through aRight */
+  u8 *aOut = *paOut;              /* Output cursor */
+  int iCol;                       /* Used to iterate from 0 to nCol */
+
+  for(iCol=0; iCol<nCol; iCol++){
+    int n1 = sessionSerialLen(a1);
+    int n2 = sessionSerialLen(a2);
+    if( *a2 ){
+      memcpy(aOut, a2, n2);
+      aOut += n2;
+    }else{
+      memcpy(aOut, a1, n1);
+      aOut += n1;
+    }
+    a1 += n1;
+    a2 += n2;
+  }
+
+  *paOut = aOut;
+}
+
+/*
+** This is a helper function used by sessionMergeUpdate().
+**
+** When this function is called, both *paOne and *paTwo point to a value
+** within a change record. Before it returns, both have been advanced so
+** as to point to the next value in the record.
+**
+** If, when this function is called, *paTwo points to a valid value (i.e.
+** *paTwo[0] is not 0x00 - the "no value" placeholder), a copy of the *paTwo
+** pointer is returned and *pnVal is set to the number of bytes in the
+** serialized value. Otherwise, a copy of *paOne is returned and *pnVal
+** set to the number of bytes in the value at *paOne. If *paOne points
+** to the "no value" placeholder, *pnVal is set to 1. In other words:
+**
+**   if( *paTwo is valid ) return *paTwo;
+**   return *paOne;
+**
+*/
+static u8 *sessionMergeValue(
+  u8 **paOne,                     /* IN/OUT: Left-hand buffer pointer */
+  u8 **paTwo,                     /* IN/OUT: Right-hand buffer pointer */
+  int *pnVal                      /* OUT: Bytes in returned value */
+){
+  u8 *a1 = *paOne;
+  u8 *a2 = *paTwo;
+  u8 *pRet = 0;
+  int n1;
+
+  assert( a1 );
+  if( a2 ){
+    int n2 = sessionSerialLen(a2);
+    if( *a2 ){
+      *pnVal = n2;
+      pRet = a2;
+    }
+    *paTwo = &a2[n2];
+  }
+
+  n1 = sessionSerialLen(a1);
+  if( pRet==0 ){
+    *pnVal = n1;
+    pRet = a1;
+  }
+  *paOne = &a1[n1];
+
+  return pRet;
+}
+
+/*
+** This function is used by changeset_concat() to merge two UPDATE changes
+** on the same row.
+*/
+static int sessionMergeUpdate(
+  u8 **paOut,                     /* IN/OUT: Pointer to output buffer */
+  SessionTable *pTab,             /* Table change pertains to */
+  int bPatchset,                  /* True if records are patchset records */
+  u8 *aOldRecord1,                /* old.* record for first change */
+  u8 *aOldRecord2,                /* old.* record for second change */
+  u8 *aNewRecord1,                /* new.* record for first change */
+  u8 *aNewRecord2                 /* new.* record for second change */
+){
+  u8 *aOld1 = aOldRecord1;
+  u8 *aOld2 = aOldRecord2;
+  u8 *aNew1 = aNewRecord1;
+  u8 *aNew2 = aNewRecord2;
+
+  u8 *aOut = *paOut;
+  int i;
+
+  if( bPatchset==0 ){
+    int bRequired = 0;
+
+    assert( aOldRecord1 && aNewRecord1 );
+
+    /* Write the old.* vector first. */
+    for(i=0; i<pTab->nCol; i++){
+      int nOld;
+      u8 *aOld;
+      int nNew;
+      u8 *aNew;
+
+      aOld = sessionMergeValue(&aOld1, &aOld2, &nOld);
+      aNew = sessionMergeValue(&aNew1, &aNew2, &nNew);
+      if( pTab->abPK[i] || nOld!=nNew || memcmp(aOld, aNew, nNew) ){
+        if( pTab->abPK[i]==0 ) bRequired = 1;
+        memcpy(aOut, aOld, nOld);
+        aOut += nOld;
+      }else{
+        *(aOut++) = '\0';
+      }
+    }
+
+    if( !bRequired ) return 0;
+  }
+
+  /* Write the new.* vector */
+  aOld1 = aOldRecord1;
+  aOld2 = aOldRecord2;
+  aNew1 = aNewRecord1;
+  aNew2 = aNewRecord2;
+  for(i=0; i<pTab->nCol; i++){
+    int nOld;
+    u8 *aOld;
+    int nNew;
+    u8 *aNew;
+
+    aOld = sessionMergeValue(&aOld1, &aOld2, &nOld);
+    aNew = sessionMergeValue(&aNew1, &aNew2, &nNew);
+    if( bPatchset==0
+     && (pTab->abPK[i] || (nOld==nNew && 0==memcmp(aOld, aNew, nNew)))
+    ){
+      *(aOut++) = '\0';
+    }else{
+      memcpy(aOut, aNew, nNew);
+      aOut += nNew;
+    }
+  }
+
+  *paOut = aOut;
+  return 1;
+}
+
+/*
+** This function is only called from within a pre-update-hook callback.
+** It determines if the current pre-update-hook change affects the same row
+** as the change stored in argument pChange. If so, it returns true. Otherwise
+** if the pre-update-hook does not affect the same row as pChange, it returns
+** false.
+*/
+static int sessionPreupdateEqual(
+  sqlite3_session *pSession,      /* Session object that owns SessionTable */
+  i64 iRowid,                     /* Rowid value if pTab->bRowid */
+  SessionTable *pTab,             /* Table associated with change */
+  SessionChange *pChange,         /* Change to compare to */
+  int op                          /* Current pre-update operation */
+){
+  int iCol;                       /* Used to iterate through columns */
+  u8 *a = pChange->aRecord;       /* Cursor used to scan change record */
+
+  if( pTab->bRowid ){
+    if( a[0]!=SQLITE_INTEGER ) return 0;
+    return sessionGetI64(&a[1])==iRowid;
+  }
+
+  assert( op==SQLITE_INSERT || op==SQLITE_UPDATE || op==SQLITE_DELETE );
+  for(iCol=0; iCol<pTab->nCol; iCol++){
+    if( !pTab->abPK[iCol] ){
+      a += sessionSerialLen(a);
+    }else{
+      sqlite3_value *pVal;        /* Value returned by preupdate_new/old */
+      int rc;                     /* Error code from preupdate_new/old */
+      int eType = *a++;           /* Type of value from change record */
+      int iIdx = pTab->aiIdx[iCol];
+
+      /* The following calls to preupdate_new() and preupdate_old() can not
+      ** fail. This is because they cache their return values, and by the
+      ** time control flows to here they have already been called once from
+      ** within sessionPreupdateHash(). The first two asserts below verify
+      ** this (that the method has already been called). */
+      if( op==SQLITE_INSERT ){
+        /* assert( db->pPreUpdate->pNewUnpacked || db->pPreUpdate->aNew ); */
+        rc = pSession->hook.xNew(pSession->hook.pCtx, iIdx, &pVal);
+      }else{
+        /* assert( db->pPreUpdate->pUnpacked ); */
+        rc = pSession->hook.xOld(pSession->hook.pCtx, iIdx, &pVal);
+      }
+      assert( rc==SQLITE_OK );
+      (void)rc;                   /* Suppress warning about unused variable */
+      if( sqlite3_value_type(pVal)!=eType ) return 0;
+
+      /* A SessionChange object never has a NULL value in a PK column */
+      assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT
+           || eType==SQLITE_BLOB    || eType==SQLITE_TEXT
+      );
+
+      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+        i64 iVal = sessionGetI64(a);
+        a += 8;
+        if( eType==SQLITE_INTEGER ){
+          if( sqlite3_value_int64(pVal)!=iVal ) return 0;
+        }else{
+          double rVal;
+          assert( sizeof(iVal)==8 && sizeof(rVal)==8 );
+          memcpy(&rVal, &iVal, 8);
+          if( sqlite3_value_double(pVal)!=rVal ) return 0;
+        }
+      }else{
+        int n;
+        const u8 *z;
+        a += sessionVarintGet(a, &n);
+        if( sqlite3_value_bytes(pVal)!=n ) return 0;
+        if( eType==SQLITE_TEXT ){
+          z = sqlite3_value_text(pVal);
+        }else{
+          z = sqlite3_value_blob(pVal);
+        }
+        if( n>0 && memcmp(a, z, n) ) return 0;
+        a += n;
+      }
+    }
+  }
+
+  return 1;
+}
+
+/*
+** If required, grow the hash table used to store changes on table pTab
+** (part of the session pSession). If a fatal OOM error occurs, set the
+** session object to failed and return SQLITE_ERROR. Otherwise, return
+** SQLITE_OK.
+**
+** It is possible that a non-fatal OOM error occurs in this function. In
+** that case the hash-table does not grow, but SQLITE_OK is returned anyway.
+** Growing the hash table in this case is a performance optimization only,
+** it is not required for correct operation.
+*/
+static int sessionGrowHash(
+  sqlite3_session *pSession,      /* For memory accounting. May be NULL */
+  int bPatchset,
+  SessionTable *pTab
+){
+  if( pTab->nChange==0 || pTab->nEntry>=(pTab->nChange/2) ){
+    int i;
+    SessionChange **apNew;
+    sqlite3_int64 nNew = 2*(sqlite3_int64)(pTab->nChange ? pTab->nChange : 128);
+
+    apNew = (SessionChange**)sessionMalloc64(
+        pSession, sizeof(SessionChange*) * nNew
+    );
+    if( apNew==0 ){
+      if( pTab->nChange==0 ){
+        return SQLITE_ERROR;
+      }
+      return SQLITE_OK;
+    }
+    memset(apNew, 0, sizeof(SessionChange *) * nNew);
+
+    for(i=0; i<pTab->nChange; i++){
+      SessionChange *p;
+      SessionChange *pNext;
+      for(p=pTab->apChange[i]; p; p=pNext){
+        int bPkOnly = (p->op==SQLITE_DELETE && bPatchset);
+        int iHash = sessionChangeHash(pTab, bPkOnly, p->aRecord, nNew);
+        pNext = p->pNext;
+        p->pNext = apNew[iHash];
+        apNew[iHash] = p;
+      }
+    }
+
+    sessionFree(pSession, pTab->apChange);
+    pTab->nChange = nNew;
+    pTab->apChange = apNew;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** This function queries the database for the names of the columns of table
+** zThis, in schema zDb.
+**
+** Otherwise, if they are not NULL, variable *pnCol is set to the number
+** of columns in the database table and variable *pzTab is set to point to a
+** nul-terminated copy of the table name. *pazCol (if not NULL) is set to
+** point to an array of pointers to column names. And *pabPK (again, if not
+** NULL) is set to point to an array of booleans - true if the corresponding
+** column is part of the primary key.
+**
+** For example, if the table is declared as:
+**
+**     CREATE TABLE tbl1(w, x DEFAULT 'abc', y, z, PRIMARY KEY(w, z));
+**
+** Then the five output variables are populated as follows:
+**
+**     *pnCol  = 4
+**     *pzTab  = "tbl1"
+**     *pazCol = {"w", "x", "y", "z"}
+**     *pazDflt = {NULL, 'abc', NULL, NULL}
+**     *pabPK  = {1, 0, 0, 1}
+**
+** All returned buffers are part of the same single allocation, which must
+** be freed using sqlite3_free() by the caller
+*/
+static int sessionTableInfo(
+  sqlite3_session *pSession,      /* For memory accounting. May be NULL */
+  sqlite3 *db,                    /* Database connection */
+  const char *zDb,                /* Name of attached database (e.g. "main") */
+  const char *zThis,              /* Table name */
+  int *pnCol,                     /* OUT: number of columns */
+  int *pnTotalCol,                /* OUT: number of hidden columns */
+  const char **pzTab,             /* OUT: Copy of zThis */
+  const char ***pazCol,           /* OUT: Array of column names for table */
+  const char ***pazDflt,          /* OUT: Array of default value expressions */
+  int **paiIdx,                   /* OUT: Array of xNew/xOld indexes */
+  u8 **pabPK,                     /* OUT: Array of booleans - true for PK col */
+  int *pbRowid                    /* OUT: True if only PK is a rowid */
+){
+  char *zPragma;
+  sqlite3_stmt *pStmt;
+  int rc;
+  sqlite3_int64 nByte;
+  int nDbCol = 0;
+  int nThis;
+  int i;
+  u8 *pAlloc = 0;
+  char **azCol = 0;
+  char **azDflt = 0;
+  u8 *abPK = 0;
+  int *aiIdx = 0;
+  int bRowid = 0;                 /* Set to true to use rowid as PK */
+
+  assert( pazCol && pabPK );
+
+  *pazCol = 0;
+  *pabPK = 0;
+  *pnCol = 0;
+  if( pnTotalCol ) *pnTotalCol = 0;
+  if( paiIdx ) *paiIdx = 0;
+  if( pzTab ) *pzTab = 0;
+  if( pazDflt ) *pazDflt = 0;
+
+  nThis = sqlite3Strlen30(zThis);
+  if( nThis==12 && 0==sqlite3_stricmp("sqlite_stat1", zThis) ){
+    rc = sqlite3_table_column_metadata(db, zDb, zThis, 0, 0, 0, 0, 0, 0);
+    if( rc==SQLITE_OK ){
+      /* For sqlite_stat1, pretend that (tbl,idx) is the PRIMARY KEY. */
+      zPragma = sqlite3_mprintf(
+          "SELECT 0, 'tbl',  '', 0, '', 1, 0     UNION ALL "
+          "SELECT 1, 'idx',  '', 0, '', 2, 0     UNION ALL "
+          "SELECT 2, 'stat', '', 0, '', 0, 0"
+      );
+    }else if( rc==SQLITE_ERROR ){
+      zPragma = sqlite3_mprintf("");
+    }else{
+      return rc;
+    }
+  }else{
+    zPragma = sqlite3_mprintf("PRAGMA '%q'.table_xinfo('%q')", zDb, zThis);
+  }
+  if( !zPragma ){
+    return SQLITE_NOMEM;
+  }
+
+  rc = sqlite3_prepare_v2(db, zPragma, -1, &pStmt, 0);
+  sqlite3_free(zPragma);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  nByte = nThis + 1;
+  bRowid = (pbRowid!=0);
+  while( SQLITE_ROW==sqlite3_step(pStmt) ){
+    nByte += sqlite3_column_bytes(pStmt, 1);          /* name */
+    nByte += sqlite3_column_bytes(pStmt, 4);          /* dflt_value */
+    if( sqlite3_column_int(pStmt, 6)==0 ){            /* !hidden */
+      nDbCol++;
+    }
+    if( sqlite3_column_int(pStmt, 5) ) bRowid = 0;    /* pk */
+  }
+  if( nDbCol==0 ) bRowid = 0;
+  nDbCol += bRowid;
+  nByte += strlen(SESSIONS_ROWID);
+  rc = sqlite3_reset(pStmt);
+
+  if( rc==SQLITE_OK ){
+    nByte += nDbCol * (sizeof(const char *)*2 +sizeof(int)+sizeof(u8) + 1 + 1);
+    pAlloc = sessionMalloc64(pSession, nByte);
+    if( pAlloc==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pAlloc, 0, nByte);
+    }
+  }
+  if( rc==SQLITE_OK ){
+    azCol = (char **)pAlloc;
+    azDflt = (char**)&azCol[nDbCol];
+    aiIdx = (int*)&azDflt[nDbCol];
+    abPK = (u8 *)&aiIdx[nDbCol];
+    pAlloc = &abPK[nDbCol];
+    if( pzTab ){
+      memcpy(pAlloc, zThis, nThis+1);
+      *pzTab = (char *)pAlloc;
+      pAlloc += nThis+1;
+    }
+
+    i = 0;
+    if( bRowid ){
+      size_t nName = strlen(SESSIONS_ROWID);
+      memcpy(pAlloc, SESSIONS_ROWID, nName+1);
+      azCol[i] = (char*)pAlloc;
+      pAlloc += nName+1;
+      abPK[i] = 1;
+      aiIdx[i] = -1;
+      i++;
+    }
+    while( SQLITE_ROW==sqlite3_step(pStmt) ){
+      if( sqlite3_column_int(pStmt, 6)==0 ){            /* !hidden */
+        int nName = sqlite3_column_bytes(pStmt, 1);
+        int nDflt = sqlite3_column_bytes(pStmt, 4);
+        const unsigned char *zName = sqlite3_column_text(pStmt, 1);
+        const unsigned char *zDflt = sqlite3_column_text(pStmt, 4);
+
+        if( zName==0 ) break;
+        memcpy(pAlloc, zName, nName+1);
+        azCol[i] = (char *)pAlloc;
+        pAlloc += nName+1;
+        if( zDflt ){
+          memcpy(pAlloc, zDflt, nDflt+1);
+          azDflt[i] = (char *)pAlloc;
+          pAlloc += nDflt+1;
+        }else{
+          azDflt[i] = 0;
+        }
+        abPK[i] = sqlite3_column_int(pStmt, 5);
+        aiIdx[i] = sqlite3_column_int(pStmt, 0);
+        i++;
+      }
+      if( pnTotalCol ) (*pnTotalCol)++;
+    }
+    rc = sqlite3_reset(pStmt);
+  }
+
+  /* If successful, populate the output variables. Otherwise, zero them and
+  ** free any allocation made. An error code will be returned in this case.
+  */
+  if( rc==SQLITE_OK ){
+    *pazCol = (const char**)azCol;
+    if( pazDflt ) *pazDflt = (const char**)azDflt;
+    *pabPK = abPK;
+    *pnCol = nDbCol;
+    if( paiIdx ) *paiIdx = aiIdx;
+  }else{
+    sessionFree(pSession, azCol);
+  }
+  if( pbRowid ) *pbRowid = bRowid;
+  sqlite3_finalize(pStmt);
+  return rc;
+}
+
+/*
+** This function is called to initialize the SessionTable.nCol, azCol[]
+** abPK[] and azDflt[] members of SessionTable object pTab. If these
+** fields are already initilialized, this function is a no-op.
+**
+** If an error occurs, an error code is stored in sqlite3_session.rc and
+** non-zero returned. Or, if no error occurs but the table has no primary
+** key, sqlite3_session.rc is left set to SQLITE_OK and non-zero returned to
+** indicate that updates on this table should be ignored. SessionTable.abPK
+** is set to NULL in this case.
+*/
+static int sessionInitTable(
+  sqlite3_session *pSession,      /* Optional session handle */
+  SessionTable *pTab,             /* Table object to initialize */
+  sqlite3 *db,                    /* Database handle to read schema from */
+  const char *zDb                 /* Name of db - "main", "temp" etc. */
+){
+  int rc = SQLITE_OK;
+
+  if( pTab->nCol==0 ){
+    u8 *abPK;
+    assert( pTab->azCol==0 || pTab->abPK==0 );
+    rc = sessionTableInfo(pSession, db, zDb,
+        pTab->zName, &pTab->nCol, &pTab->nTotalCol, 0, &pTab->azCol,
+        &pTab->azDflt, &pTab->aiIdx, &abPK,
+        ((pSession==0 || pSession->bImplicitPK) ? &pTab->bRowid : 0)
+    );
+    if( rc==SQLITE_OK ){
+      int i;
+      for(i=0; i<pTab->nCol; i++){
+        if( abPK[i] ){
+          pTab->abPK = abPK;
+          break;
+        }
+      }
+      if( 0==sqlite3_stricmp("sqlite_stat1", pTab->zName) ){
+        pTab->bStat1 = 1;
+      }
+
+      if( pSession && pSession->bEnableSize ){
+        pSession->nMaxChangesetSize += (
+          1 + sessionVarintLen(pTab->nCol) + pTab->nCol + strlen(pTab->zName)+1
+        );
+      }
+    }
+  }
+
+  if( pSession ){
+    pSession->rc = rc;
+    return (rc || pTab->abPK==0);
+  }
+  return rc;
+}
+
+/*
+** Re-initialize table object pTab.
+*/
+static int sessionReinitTable(sqlite3_session *pSession, SessionTable *pTab){
+  int nCol = 0;
+  int nTotalCol = 0;
+  const char **azCol = 0;
+  const char **azDflt = 0;
+  int *aiIdx = 0;
+  u8 *abPK = 0;
+  int bRowid = 0;
+
+  assert( pSession->rc==SQLITE_OK );
+
+  pSession->rc = sessionTableInfo(pSession, pSession->db, pSession->zDb,
+      pTab->zName, &nCol, &nTotalCol, 0, &azCol, &azDflt, &aiIdx, &abPK,
+      (pSession->bImplicitPK ? &bRowid : 0)
+  );
+  if( pSession->rc==SQLITE_OK ){
+    if( pTab->nCol>nCol || pTab->bRowid!=bRowid ){
+      pSession->rc = SQLITE_SCHEMA;
+    }else{
+      int ii;
+      int nOldCol = pTab->nCol;
+      for(ii=0; ii<nCol; ii++){
+        if( ii<pTab->nCol ){
+          if( pTab->abPK[ii]!=abPK[ii] ){
+            pSession->rc = SQLITE_SCHEMA;
+          }
+        }else if( abPK[ii] ){
+          pSession->rc = SQLITE_SCHEMA;
+        }
+      }
+
+      if( pSession->rc==SQLITE_OK ){
+        const char **a = pTab->azCol;
+        pTab->azCol = azCol;
+        pTab->nCol = nCol;
+        pTab->nTotalCol = nTotalCol;
+        pTab->azDflt = azDflt;
+        pTab->abPK = abPK;
+        pTab->aiIdx = aiIdx;
+        azCol = a;
+      }
+      if( pSession->bEnableSize ){
+        pSession->nMaxChangesetSize += (nCol - nOldCol);
+        pSession->nMaxChangesetSize += sessionVarintLen(nCol);
+        pSession->nMaxChangesetSize -= sessionVarintLen(nOldCol);
+      }
+    }
+  }
+
+  sqlite3_free((char*)azCol);
+  return pSession->rc;
+}
+
+/*
+** Session-change object (*pp) contains an old.* record with fewer than
+** nCol fields. This function updates it with the default values for
+** the missing fields.
+*/
+static void sessionUpdateOneChange(
+  sqlite3_session *pSession,      /* For memory accounting */
+  int *pRc,                       /* IN/OUT: Error code */
+  SessionChange **pp,             /* IN/OUT: Change object to update */
+  int nCol,                       /* Number of columns now in table */
+  sqlite3_stmt *pDflt             /* SELECT <default-values...> */
+){
+  SessionChange *pOld = *pp;
+
+  while( pOld->nRecordField<nCol ){
+    SessionChange *pNew = 0;
+    int nByte = 0;
+    int nIncr = 0;
+    int iField = pOld->nRecordField;
+    int eType = sqlite3_column_type(pDflt, iField);
+    switch( eType ){
+      case SQLITE_NULL:
+        nIncr = 1;
+        break;
+      case SQLITE_INTEGER:
+      case SQLITE_FLOAT:
+        nIncr = 9;
+        break;
+      default: {
+        int n = sqlite3_column_bytes(pDflt, iField);
+        nIncr = 1 + sessionVarintLen(n) + n;
+        assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
+        break;
+      }
+    }
+
+    nByte = nIncr + (sizeof(SessionChange) + pOld->nRecord);
+    pNew = sessionMalloc64(pSession, nByte);
+    if( pNew==0 ){
+      *pRc = SQLITE_NOMEM;
+      return;
+    }else{
+      memcpy(pNew, pOld, sizeof(SessionChange));
+      pNew->aRecord = (u8*)&pNew[1];
+      memcpy(pNew->aRecord, pOld->aRecord, pOld->nRecord);
+      pNew->aRecord[pNew->nRecord++] = (u8)eType;
+      switch( eType ){
+        case SQLITE_INTEGER: {
+          i64 iVal = sqlite3_column_int64(pDflt, iField);
+          sessionPutI64(&pNew->aRecord[pNew->nRecord], iVal);
+          pNew->nRecord += 8;
+          break;
+        }
+
+        case SQLITE_FLOAT: {
+          double rVal = sqlite3_column_double(pDflt, iField);
+          i64 iVal = 0;
+          memcpy(&iVal, &rVal, sizeof(rVal));
+          sessionPutI64(&pNew->aRecord[pNew->nRecord], iVal);
+          pNew->nRecord += 8;
+          break;
+        }
+
+        case SQLITE_TEXT: {
+          int n = sqlite3_column_bytes(pDflt, iField);
+          const char *z = (const char*)sqlite3_column_text(pDflt, iField);
+          pNew->nRecord += sessionVarintPut(&pNew->aRecord[pNew->nRecord], n);
+          memcpy(&pNew->aRecord[pNew->nRecord], z, n);
+          pNew->nRecord += n;
+          break;
+        }
+
+        case SQLITE_BLOB: {
+          int n = sqlite3_column_bytes(pDflt, iField);
+          const u8 *z = (const u8*)sqlite3_column_blob(pDflt, iField);
+          pNew->nRecord += sessionVarintPut(&pNew->aRecord[pNew->nRecord], n);
+          memcpy(&pNew->aRecord[pNew->nRecord], z, n);
+          pNew->nRecord += n;
+          break;
+        }
+
+        default:
+          assert( eType==SQLITE_NULL );
+          break;
+      }
+
+      sessionFree(pSession, pOld);
+      *pp = pOld = pNew;
+      pNew->nRecordField++;
+      pNew->nMaxSize += nIncr;
+      if( pSession ){
+        pSession->nMaxChangesetSize += nIncr;
+      }
+    }
+  }
+}
+
+/*
+** Ensure that there is room in the buffer to append nByte bytes of data.
+** If not, use sqlite3_realloc() to grow the buffer so that there is.
+**
+** If successful, return zero. Otherwise, if an OOM condition is encountered,
+** set *pRc to SQLITE_NOMEM and return non-zero.
+*/
+static int sessionBufferGrow(SessionBuffer *p, i64 nByte, int *pRc){
+#define SESSION_MAX_BUFFER_SZ (0x7FFFFF00 - 1)
+  i64 nReq = p->nBuf + nByte;
+  if( *pRc==SQLITE_OK && nReq>p->nAlloc ){
+    u8 *aNew;
+    i64 nNew = p->nAlloc ? p->nAlloc : 128;
+
+    do {
+      nNew = nNew*2;
+    }while( nNew<nReq );
+
+    /* The value of SESSION_MAX_BUFFER_SZ is copied from the implementation
+    ** of sqlite3_realloc64(). Allocations greater than this size in bytes
+    ** always fail. It is used here to ensure that this routine can always
+    ** allocate up to this limit - instead of up to the largest power of
+    ** two smaller than the limit.  */
+    if( nNew>SESSION_MAX_BUFFER_SZ ){
+      nNew = SESSION_MAX_BUFFER_SZ;
+      if( nNew<nReq ){
+        *pRc = SQLITE_NOMEM;
+        return 1;
+      }
+    }
+
+    aNew = (u8 *)sqlite3_realloc64(p->aBuf, nNew);
+    if( 0==aNew ){
+      *pRc = SQLITE_NOMEM;
+    }else{
+      p->aBuf = aNew;
+      p->nAlloc = nNew;
+    }
+  }
+  return (*pRc!=SQLITE_OK);
+}
+
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append a string to the buffer. All bytes in the string
+** up to (but not including) the nul-terminator are written to the buffer.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendStr(
+  SessionBuffer *p,
+  const char *zStr,
+  int *pRc
+){
+  int nStr = sqlite3Strlen30(zStr);
+  if( 0==sessionBufferGrow(p, nStr+1, pRc) ){
+    memcpy(&p->aBuf[p->nBuf], zStr, nStr);
+    p->nBuf += nStr;
+    p->aBuf[p->nBuf] = 0x00;
+  }
+}
+
+/*
+** Format a string using printf() style formatting and then append it to the
+** buffer using sessionAppendString().
+*/
+static void sessionAppendPrintf(
+  SessionBuffer *p,               /* Buffer to append to */
+  int *pRc,
+  const char *zFmt,
+  ...
+){
+  if( *pRc==SQLITE_OK ){
+    char *zApp = 0;
+    va_list ap;
+    va_start(ap, zFmt);
+    zApp = sqlite3_vmprintf(zFmt, ap);
+    if( zApp==0 ){
+      *pRc = SQLITE_NOMEM;
+    }else{
+      sessionAppendStr(p, zApp, pRc);
+    }
+    va_end(ap);
+    sqlite3_free(zApp);
+  }
+}
+
+/*
+** Prepare a statement against database handle db that SELECTs a single
+** row containing the default values for each column in table pTab. For
+** example, if pTab is declared as:
+**
+**   CREATE TABLE pTab(a PRIMARY KEY, b DEFAULT 123, c DEFAULT 'abcd');
+**
+** Then this function prepares and returns the SQL statement:
+**
+**   SELECT NULL, 123, 'abcd';
+*/
+static int sessionPrepareDfltStmt(
+  sqlite3 *db,                    /* Database handle */
+  SessionTable *pTab,             /* Table to prepare statement for */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  SessionBuffer sql = {0,0,0};
+  int rc = SQLITE_OK;
+  const char *zSep = " ";
+  int ii = 0;
+
+  *ppStmt = 0;
+  sessionAppendPrintf(&sql, &rc, "SELECT");
+  for(ii=0; ii<pTab->nCol; ii++){
+    const char *zDflt = pTab->azDflt[ii] ? pTab->azDflt[ii] : "NULL";
+    sessionAppendPrintf(&sql, &rc, "%s%s", zSep, zDflt);
+    zSep = ", ";
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_prepare_v2(db, (const char*)sql.aBuf, -1, ppStmt, 0);
+  }
+  sqlite3_free(sql.aBuf);
+
+  return rc;
+}
+
+/*
+** Table pTab has one or more existing change-records with old.* records
+** with fewer than pTab->nCol columns. This function updates all such
+** change-records with the default values for the missing columns.
+*/
+static int sessionUpdateChanges(sqlite3_session *pSession, SessionTable *pTab){
+  sqlite3_stmt *pStmt = 0;
+  int rc = pSession->rc;
+
+  rc = sessionPrepareDfltStmt(pSession->db, pTab, &pStmt);
+  if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+    int ii = 0;
+    SessionChange **pp = 0;
+    for(ii=0; ii<pTab->nChange; ii++){
+      for(pp=&pTab->apChange[ii]; *pp; pp=&((*pp)->pNext)){
+        if( (*pp)->nRecordField!=pTab->nCol ){
+          sessionUpdateOneChange(pSession, &rc, pp, pTab->nCol, pStmt);
+        }
+      }
+    }
+  }
+
+  pSession->rc = rc;
+  rc = sqlite3_finalize(pStmt);
+  if( pSession->rc==SQLITE_OK ) pSession->rc = rc;
+  return pSession->rc;
+}
+
+/*
+** Versions of the four methods in object SessionHook for use with the
+** sqlite_stat1 table. The purpose of this is to substitute a zero-length
+** blob each time a NULL value is read from the "idx" column of the
+** sqlite_stat1 table.
+*/
+typedef struct SessionStat1Ctx SessionStat1Ctx;
+struct SessionStat1Ctx {
+  SessionHook hook;
+  sqlite3_session *pSession;
+};
+static int sessionStat1Old(void *pCtx, int iCol, sqlite3_value **ppVal){
+  SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
+  sqlite3_value *pVal = 0;
+  int rc = p->hook.xOld(p->hook.pCtx, iCol, &pVal);
+  if( rc==SQLITE_OK && iCol==1 && sqlite3_value_type(pVal)==SQLITE_NULL ){
+    pVal = p->pSession->pZeroBlob;
+  }
+  *ppVal = pVal;
+  return rc;
+}
+static int sessionStat1New(void *pCtx, int iCol, sqlite3_value **ppVal){
+  SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
+  sqlite3_value *pVal = 0;
+  int rc = p->hook.xNew(p->hook.pCtx, iCol, &pVal);
+  if( rc==SQLITE_OK && iCol==1 && sqlite3_value_type(pVal)==SQLITE_NULL ){
+    pVal = p->pSession->pZeroBlob;
+  }
+  *ppVal = pVal;
+  return rc;
+}
+static int sessionStat1Count(void *pCtx){
+  SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
+  return p->hook.xCount(p->hook.pCtx);
+}
+static int sessionStat1Depth(void *pCtx){
+  SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
+  return p->hook.xDepth(p->hook.pCtx);
+}
+
+static int sessionUpdateMaxSize(
+  int op,
+  sqlite3_session *pSession,      /* Session object pTab is attached to */
+  SessionTable *pTab,             /* Table that change applies to */
+  SessionChange *pC               /* Update pC->nMaxSize */
+){
+  i64 nNew = 2;
+  if( pC->op==SQLITE_INSERT ){
+    if( pTab->bRowid ) nNew += 9;
+    if( op!=SQLITE_DELETE ){
+      int ii;
+      for(ii=0; ii<pTab->nCol; ii++){
+        sqlite3_value *p = 0;
+        pSession->hook.xNew(pSession->hook.pCtx, pTab->aiIdx[ii], &p);
+        sessionSerializeValue(0, p, &nNew);
+      }
+    }
+  }else if( op==SQLITE_DELETE ){
+    nNew += pC->nRecord;
+    if( sqlite3_preupdate_blobwrite(pSession->db)>=0 ){
+      nNew += pC->nRecord;
+    }
+  }else{
+    int ii;
+    u8 *pCsr = pC->aRecord;
+    if( pTab->bRowid ){
+      nNew += 9 + 1;
+      pCsr += 9;
+    }
+    for(ii=pTab->bRowid; ii<pTab->nCol; ii++){
+      int bChanged = 1;
+      int nOld = 0;
+      int eType;
+      int iIdx = pTab->aiIdx[ii];
+      sqlite3_value *p = 0;
+      pSession->hook.xNew(pSession->hook.pCtx, iIdx, &p);
+      if( p==0 ){
+        return SQLITE_NOMEM;
+      }
+
+      eType = *pCsr++;
+      switch( eType ){
+        case SQLITE_NULL:
+          bChanged = sqlite3_value_type(p)!=SQLITE_NULL;
+          break;
+
+        case SQLITE_FLOAT:
+        case SQLITE_INTEGER: {
+          if( eType==sqlite3_value_type(p) ){
+            sqlite3_int64 iVal = sessionGetI64(pCsr);
+            if( eType==SQLITE_INTEGER ){
+              bChanged = (iVal!=sqlite3_value_int64(p));
+            }else{
+              double dVal;
+              memcpy(&dVal, &iVal, 8);
+              bChanged = (dVal!=sqlite3_value_double(p));
+            }
+          }
+          nOld = 8;
+          pCsr += 8;
+          break;
+        }
+
+        default: {
+          int nByte;
+          nOld = sessionVarintGet(pCsr, &nByte);
+          pCsr += nOld;
+          nOld += nByte;
+          assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
+          if( eType==sqlite3_value_type(p)
+           && nByte==sqlite3_value_bytes(p)
+           && (nByte==0 || 0==memcmp(pCsr, sqlite3_value_blob(p), nByte))
+          ){
+            bChanged = 0;
+          }
+          pCsr += nByte;
+          break;
+        }
+      }
+
+      if( bChanged && pTab->abPK[ii] ){
+        nNew = pC->nRecord + 2;
+        break;
+      }
+
+      if( bChanged ){
+        nNew += 1 + nOld;
+        sessionSerializeValue(0, p, &nNew);
+      }else if( pTab->abPK[ii] ){
+        nNew += 2 + nOld;
+      }else{
+        nNew += 2;
+      }
+    }
+  }
+
+  if( nNew>pC->nMaxSize ){
+    int nIncr = nNew - pC->nMaxSize;
+    pC->nMaxSize = nNew;
+    pSession->nMaxChangesetSize += nIncr;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is only called from with a pre-update-hook reporting a
+** change on table pTab (attached to session pSession). The type of change
+** (UPDATE, INSERT, DELETE) is specified by the first argument.
+**
+** Unless one is already present or an error occurs, an entry is added
+** to the changed-rows hash table associated with table pTab.
+*/
+static void sessionPreupdateOneChange(
+  int op,                         /* One of SQLITE_UPDATE, INSERT, DELETE */
+  i64 iRowid,
+  sqlite3_session *pSession,      /* Session object pTab is attached to */
+  SessionTable *pTab              /* Table that change applies to */
+){
+  int iHash;
+  int bNull = 0;
+  int rc = SQLITE_OK;
+  int nExpect = 0;
+  SessionStat1Ctx stat1 = {{0,0,0,0,0},0};
+
+  if( pSession->rc ) return;
+
+  /* Load table details if required */
+  if( sessionInitTable(pSession, pTab, pSession->db, pSession->zDb) ) return;
+
+  /* Check the number of columns in this xPreUpdate call matches the
+  ** number of columns in the table.  */
+  nExpect = pSession->hook.xCount(pSession->hook.pCtx);
+  if( pTab->nTotalCol<nExpect ){
+    if( sessionReinitTable(pSession, pTab) ) return;
+    if( sessionUpdateChanges(pSession, pTab) ) return;
+  }
+  if( pTab->nTotalCol!=nExpect ){
+    pSession->rc = SQLITE_SCHEMA;
+    return;
+  }
+
+  /* Grow the hash table if required */
+  if( sessionGrowHash(pSession, 0, pTab) ){
+    pSession->rc = SQLITE_NOMEM;
+    return;
+  }
+
+  if( pTab->bStat1 ){
+    stat1.hook = pSession->hook;
+    stat1.pSession = pSession;
+    pSession->hook.pCtx = (void*)&stat1;
+    pSession->hook.xNew = sessionStat1New;
+    pSession->hook.xOld = sessionStat1Old;
+    pSession->hook.xCount = sessionStat1Count;
+    pSession->hook.xDepth = sessionStat1Depth;
+    if( pSession->pZeroBlob==0 ){
+      sqlite3_value *p = sqlite3ValueNew(0);
+      if( p==0 ){
+        rc = SQLITE_NOMEM;
+        goto error_out;
+      }
+      sqlite3ValueSetStr(p, 0, "", 0, SQLITE_STATIC);
+      pSession->pZeroBlob = p;
+    }
+  }
+
+  /* Calculate the hash-key for this change. If the primary key of the row
+  ** includes a NULL value, exit early. Such changes are ignored by the
+  ** session module. */
+  rc = sessionPreupdateHash(
+      pSession, iRowid, pTab, op==SQLITE_INSERT, &iHash, &bNull
+  );
+  if( rc!=SQLITE_OK ) goto error_out;
+
+  if( bNull==0 ){
+    /* Search the hash table for an existing record for this row. */
+    SessionChange *pC;
+    for(pC=pTab->apChange[iHash]; pC; pC=pC->pNext){
+      if( sessionPreupdateEqual(pSession, iRowid, pTab, pC, op) ) break;
+    }
+
+    if( pC==0 ){
+      /* Create a new change object containing all the old values (if
+      ** this is an SQLITE_UPDATE or SQLITE_DELETE), or just the PK
+      ** values (if this is an INSERT). */
+      sqlite3_int64 nByte;    /* Number of bytes to allocate */
+      int i;                  /* Used to iterate through columns */
+
+      assert( rc==SQLITE_OK );
+      pTab->nEntry++;
+
+      /* Figure out how large an allocation is required */
+      nByte = sizeof(SessionChange);
+      for(i=pTab->bRowid; i<pTab->nCol; i++){
+        int iIdx = pTab->aiIdx[i];
+        sqlite3_value *p = 0;
+        if( op!=SQLITE_INSERT ){
+          /* This may fail if the column has a non-NULL default and was added
+          ** using ALTER TABLE ADD COLUMN after this record was created. */
+          rc = pSession->hook.xOld(pSession->hook.pCtx, iIdx, &p);
+        }else if( pTab->abPK[i] ){
+          TESTONLY(int trc = ) pSession->hook.xNew(pSession->hook.pCtx,iIdx,&p);
+          assert( trc==SQLITE_OK );
+        }
+
+        if( rc==SQLITE_OK ){
+          /* This may fail if SQLite value p contains a utf-16 string that must
+          ** be converted to utf-8 and an OOM error occurs while doing so. */
+          rc = sessionSerializeValue(0, p, &nByte);
+        }
+        if( rc!=SQLITE_OK ) goto error_out;
+      }
+      if( pTab->bRowid ){
+        nByte += 9;               /* Size of rowid field - an integer */
+      }
+
+      /* Allocate the change object */
+      pC = (SessionChange*)sessionMalloc64(pSession, nByte);
+      if( !pC ){
+        rc = SQLITE_NOMEM;
+        goto error_out;
+      }else{
+        memset(pC, 0, sizeof(SessionChange));
+        pC->aRecord = (u8 *)&pC[1];
+      }
+
+      /* Populate the change object. None of the preupdate_old(),
+      ** preupdate_new() or SerializeValue() calls below may fail as all
+      ** required values and encodings have already been cached in memory.
+      ** It is not possible for an OOM to occur in this block. */
+      nByte = 0;
+      if( pTab->bRowid ){
+        pC->aRecord[0] = SQLITE_INTEGER;
+        sessionPutI64(&pC->aRecord[1], iRowid);
+        nByte = 9;
+      }
+      for(i=pTab->bRowid; i<pTab->nCol; i++){
+        sqlite3_value *p = 0;
+        int iIdx = pTab->aiIdx[i];
+        if( op!=SQLITE_INSERT ){
+          pSession->hook.xOld(pSession->hook.pCtx, iIdx, &p);
+        }else if( pTab->abPK[i] ){
+          pSession->hook.xNew(pSession->hook.pCtx, iIdx, &p);
+        }
+        sessionSerializeValue(&pC->aRecord[nByte], p, &nByte);
+      }
+
+      /* Add the change to the hash-table */
+      if( pSession->bIndirect || pSession->hook.xDepth(pSession->hook.pCtx) ){
+        pC->bIndirect = 1;
+      }
+      pC->nRecordField = pTab->nCol;
+      pC->nRecord = nByte;
+      pC->op = op;
+      pC->pNext = pTab->apChange[iHash];
+      pTab->apChange[iHash] = pC;
+
+    }else if( pC->bIndirect ){
+      /* If the existing change is considered "indirect", but this current
+      ** change is "direct", mark the change object as direct. */
+      if( pSession->hook.xDepth(pSession->hook.pCtx)==0
+       && pSession->bIndirect==0
+      ){
+        pC->bIndirect = 0;
+      }
+    }
+
+    assert( rc==SQLITE_OK );
+    if( pSession->bEnableSize ){
+      rc = sessionUpdateMaxSize(op, pSession, pTab, pC);
+    }
+  }
+
+
+  /* If an error has occurred, mark the session object as failed. */
+ error_out:
+  if( pTab->bStat1 ){
+    pSession->hook = stat1.hook;
+  }
+  if( rc!=SQLITE_OK ){
+    pSession->rc = rc;
+  }
+}
+
+static int sessionFindTable(
+  sqlite3_session *pSession,
+  const char *zName,
+  SessionTable **ppTab
+){
+  int rc = SQLITE_OK;
+  int nName = sqlite3Strlen30(zName);
+  SessionTable *pRet;
+
+  /* Search for an existing table */
+  for(pRet=pSession->pTable; pRet; pRet=pRet->pNext){
+    if( 0==sqlite3_strnicmp(pRet->zName, zName, nName+1) ) break;
+  }
+
+  if( pRet==0 && pSession->bAutoAttach ){
+    /* If there is a table-filter configured, invoke it. If it returns 0,
+    ** do not automatically add the new table. */
+    if( pSession->xTableFilter==0
+     || pSession->xTableFilter(pSession->pFilterCtx, zName)
+    ){
+      rc = sqlite3session_attach(pSession, zName);
+      if( rc==SQLITE_OK ){
+        pRet = pSession->pTable;
+        while( ALWAYS(pRet) && pRet->pNext ){
+          pRet = pRet->pNext;
+        }
+        assert( pRet!=0 );
+        assert( 0==sqlite3_strnicmp(pRet->zName, zName, nName+1) );
+      }
+    }
+  }
+
+  assert( rc==SQLITE_OK || pRet==0 );
+  *ppTab = pRet;
+  return rc;
+}
+
+/*
+** The 'pre-update' hook registered by this module with SQLite databases.
+*/
+static void xPreUpdate(
+  void *pCtx,                     /* Copy of third arg to preupdate_hook() */
+  sqlite3 *db,                    /* Database handle */
+  int op,                         /* SQLITE_UPDATE, DELETE or INSERT */
+  char const *zDb,                /* Database name */
+  char const *zName,              /* Table name */
+  sqlite3_int64 iKey1,            /* Rowid of row about to be deleted/updated */
+  sqlite3_int64 iKey2             /* New rowid value (for a rowid UPDATE) */
+){
+  sqlite3_session *pSession;
+  int nDb = sqlite3Strlen30(zDb);
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  (void)iKey1;
+  (void)iKey2;
+
+  for(pSession=(sqlite3_session *)pCtx; pSession; pSession=pSession->pNext){
+    SessionTable *pTab;
+
+    /* If this session is attached to a different database ("main", "temp"
+    ** etc.), or if it is not currently enabled, there is nothing to do. Skip
+    ** to the next session object attached to this database. */
+    if( pSession->bEnable==0 ) continue;
+    if( pSession->rc ) continue;
+    if( sqlite3_strnicmp(zDb, pSession->zDb, nDb+1) ) continue;
+
+    pSession->rc = sessionFindTable(pSession, zName, &pTab);
+    if( pTab ){
+      assert( pSession->rc==SQLITE_OK );
+      assert( op==SQLITE_UPDATE || iKey1==iKey2 );
+      sessionPreupdateOneChange(op, iKey1, pSession, pTab);
+      if( op==SQLITE_UPDATE ){
+        sessionPreupdateOneChange(SQLITE_INSERT, iKey2, pSession, pTab);
+      }
+    }
+  }
+}
+
+/*
+** The pre-update hook implementations.
+*/
+static int sessionPreupdateOld(void *pCtx, int iVal, sqlite3_value **ppVal){
+  return sqlite3_preupdate_old((sqlite3*)pCtx, iVal, ppVal);
+}
+static int sessionPreupdateNew(void *pCtx, int iVal, sqlite3_value **ppVal){
+  return sqlite3_preupdate_new((sqlite3*)pCtx, iVal, ppVal);
+}
+static int sessionPreupdateCount(void *pCtx){
+  return sqlite3_preupdate_count((sqlite3*)pCtx);
+}
+static int sessionPreupdateDepth(void *pCtx){
+  return sqlite3_preupdate_depth((sqlite3*)pCtx);
+}
+
+/*
+** Install the pre-update hooks on the session object passed as the only
+** argument.
+*/
+static void sessionPreupdateHooks(
+  sqlite3_session *pSession
+){
+  pSession->hook.pCtx = (void*)pSession->db;
+  pSession->hook.xOld = sessionPreupdateOld;
+  pSession->hook.xNew = sessionPreupdateNew;
+  pSession->hook.xCount = sessionPreupdateCount;
+  pSession->hook.xDepth = sessionPreupdateDepth;
+}
+
+typedef struct SessionDiffCtx SessionDiffCtx;
+struct SessionDiffCtx {
+  sqlite3_stmt *pStmt;
+  int bRowid;
+  int nOldOff;
+};
+
+/*
+** The diff hook implementations.
+*/
+static int sessionDiffOld(void *pCtx, int iVal, sqlite3_value **ppVal){
+  SessionDiffCtx *p = (SessionDiffCtx*)pCtx;
+  *ppVal = sqlite3_column_value(p->pStmt, iVal+p->nOldOff+p->bRowid);
+  return SQLITE_OK;
+}
+static int sessionDiffNew(void *pCtx, int iVal, sqlite3_value **ppVal){
+  SessionDiffCtx *p = (SessionDiffCtx*)pCtx;
+  *ppVal = sqlite3_column_value(p->pStmt, iVal+p->bRowid);
+   return SQLITE_OK;
+}
+static int sessionDiffCount(void *pCtx){
+  SessionDiffCtx *p = (SessionDiffCtx*)pCtx;
+  return (p->nOldOff ? p->nOldOff : sqlite3_column_count(p->pStmt)) - p->bRowid;
+}
+static int sessionDiffDepth(void *pCtx){
+  (void)pCtx;
+  return 0;
+}
+
+/*
+** Install the diff hooks on the session object passed as the only
+** argument.
+*/
+static void sessionDiffHooks(
+  sqlite3_session *pSession,
+  SessionDiffCtx *pDiffCtx
+){
+  pSession->hook.pCtx = (void*)pDiffCtx;
+  pSession->hook.xOld = sessionDiffOld;
+  pSession->hook.xNew = sessionDiffNew;
+  pSession->hook.xCount = sessionDiffCount;
+  pSession->hook.xDepth = sessionDiffDepth;
+}
+
+static char *sessionExprComparePK(
+  int nCol,
+  const char *zDb1, const char *zDb2,
+  const char *zTab,
+  const char **azCol, u8 *abPK
+){
+  int i;
+  const char *zSep = "";
+  char *zRet = 0;
+
+  for(i=0; i<nCol; i++){
+    if( abPK[i] ){
+      zRet = sqlite3_mprintf("%z%s\"%w\".\"%w\".\"%w\"=\"%w\".\"%w\".\"%w\"",
+          zRet, zSep, zDb1, zTab, azCol[i], zDb2, zTab, azCol[i]
+      );
+      zSep = " AND ";
+      if( zRet==0 ) break;
+    }
+  }
+
+  return zRet;
+}
+
+static char *sessionExprCompareOther(
+  int nCol,
+  const char *zDb1, const char *zDb2,
+  const char *zTab,
+  const char **azCol, u8 *abPK
+){
+  int i;
+  const char *zSep = "";
+  char *zRet = 0;
+  int bHave = 0;
+
+  for(i=0; i<nCol; i++){
+    if( abPK[i]==0 ){
+      bHave = 1;
+      zRet = sqlite3_mprintf(
+          "%z%s\"%w\".\"%w\".\"%w\" IS NOT \"%w\".\"%w\".\"%w\"",
+          zRet, zSep, zDb1, zTab, azCol[i], zDb2, zTab, azCol[i]
+      );
+      zSep = " OR ";
+      if( zRet==0 ) break;
+    }
+  }
+
+  if( bHave==0 ){
+    assert( zRet==0 );
+    zRet = sqlite3_mprintf("0");
+  }
+
+  return zRet;
+}
+
+static char *sessionSelectFindNew(
+  const char *zDb1,      /* Pick rows in this db only */
+  const char *zDb2,      /* But not in this one */
+  int bRowid,
+  const char *zTbl,      /* Table name */
+  const char *zExpr
+){
+  const char *zSel = (bRowid ? SESSIONS_ROWID ", *" : "*");
+  char *zRet = sqlite3_mprintf(
+      "SELECT %s FROM \"%w\".\"%w\" WHERE NOT EXISTS ("
+      "  SELECT 1 FROM \"%w\".\"%w\" WHERE %s"
+      ")",
+      zSel, zDb1, zTbl, zDb2, zTbl, zExpr
+  );
+  return zRet;
+}
+
+static int sessionDiffFindNew(
+  int op,
+  sqlite3_session *pSession,
+  SessionTable *pTab,
+  const char *zDb1,
+  const char *zDb2,
+  char *zExpr
+){
+  int rc = SQLITE_OK;
+  char *zStmt = sessionSelectFindNew(
+      zDb1, zDb2, pTab->bRowid, pTab->zName, zExpr
+  );
+
+  if( zStmt==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_stmt *pStmt;
+    rc = sqlite3_prepare(pSession->db, zStmt, -1, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      SessionDiffCtx *pDiffCtx = (SessionDiffCtx*)pSession->hook.pCtx;
+      pDiffCtx->pStmt = pStmt;
+      pDiffCtx->nOldOff = 0;
+      pDiffCtx->bRowid = pTab->bRowid;
+      while( SQLITE_ROW==sqlite3_step(pStmt) ){
+        i64 iRowid = (pTab->bRowid ? sqlite3_column_int64(pStmt, 0) : 0);
+        sessionPreupdateOneChange(op, iRowid, pSession, pTab);
+      }
+      rc = sqlite3_finalize(pStmt);
+    }
+    sqlite3_free(zStmt);
+  }
+
+  return rc;
+}
+
+/*
+** Return a comma-separated list of the fully-qualified (with both database
+** and table name) column names from table pTab. e.g.
+**
+**    "main"."t1"."a", "main"."t1"."b", "main"."t1"."c"
+*/
+static char *sessionAllCols(
+  const char *zDb,
+  SessionTable *pTab
+){
+  int ii;
+  char *zRet = 0;
+  for(ii=0; ii<pTab->nCol; ii++){
+    zRet = sqlite3_mprintf("%z%s\"%w\".\"%w\".\"%w\"",
+        zRet, (zRet ? ", " : ""), zDb, pTab->zName, pTab->azCol[ii]
+    );
+    if( !zRet ) break;
+  }
+  return zRet;
+}
+
+static int sessionDiffFindModified(
+  sqlite3_session *pSession,
+  SessionTable *pTab,
+  const char *zFrom,
+  const char *zExpr
+){
+  int rc = SQLITE_OK;
+
+  char *zExpr2 = sessionExprCompareOther(pTab->nCol,
+      pSession->zDb, zFrom, pTab->zName, pTab->azCol, pTab->abPK
+  );
+  if( zExpr2==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    char *z1 = sessionAllCols(pSession->zDb, pTab);
+    char *z2 = sessionAllCols(zFrom, pTab);
+    char *zStmt = sqlite3_mprintf(
+        "SELECT %s,%s FROM \"%w\".\"%w\", \"%w\".\"%w\" WHERE %s AND (%z)",
+        z1, z2, pSession->zDb, pTab->zName, zFrom, pTab->zName, zExpr, zExpr2
+    );
+    if( zStmt==0 || z1==0 || z2==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      sqlite3_stmt *pStmt;
+      rc = sqlite3_prepare(pSession->db, zStmt, -1, &pStmt, 0);
+
+      if( rc==SQLITE_OK ){
+        SessionDiffCtx *pDiffCtx = (SessionDiffCtx*)pSession->hook.pCtx;
+        pDiffCtx->pStmt = pStmt;
+        pDiffCtx->nOldOff = pTab->nCol;
+        while( SQLITE_ROW==sqlite3_step(pStmt) ){
+          i64 iRowid = (pTab->bRowid ? sqlite3_column_int64(pStmt, 0) : 0);
+          sessionPreupdateOneChange(SQLITE_UPDATE, iRowid, pSession, pTab);
+        }
+        rc = sqlite3_finalize(pStmt);
+      }
+    }
+    sqlite3_free(zStmt);
+    sqlite3_free(z1);
+    sqlite3_free(z2);
+  }
+
+  return rc;
+}
+
+SQLITE_API int sqlite3session_diff(
+  sqlite3_session *pSession,
+  const char *zFrom,
+  const char *zTbl,
+  char **pzErrMsg
+){
+  const char *zDb = pSession->zDb;
+  int rc = pSession->rc;
+  SessionDiffCtx d;
+
+  memset(&d, 0, sizeof(d));
+  sessionDiffHooks(pSession, &d);
+
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+  if( pzErrMsg ) *pzErrMsg = 0;
+  if( rc==SQLITE_OK ){
+    char *zExpr = 0;
+    sqlite3 *db = pSession->db;
+    SessionTable *pTo;            /* Table zTbl */
+
+    /* Locate and if necessary initialize the target table object */
+    rc = sessionFindTable(pSession, zTbl, &pTo);
+    if( pTo==0 ) goto diff_out;
+    if( sessionInitTable(pSession, pTo, pSession->db, pSession->zDb) ){
+      rc = pSession->rc;
+      goto diff_out;
+    }
+
+    /* Check the table schemas match */
+    if( rc==SQLITE_OK ){
+      int bHasPk = 0;
+      int bMismatch = 0;
+      int nCol;                   /* Columns in zFrom.zTbl */
+      int bRowid = 0;
+      u8 *abPK;
+      const char **azCol = 0;
+      rc = sessionTableInfo(0, db, zFrom, zTbl,
+          &nCol, 0, 0, &azCol, 0, 0, &abPK,
+          pSession->bImplicitPK ? &bRowid : 0
+      );
+      if( rc==SQLITE_OK ){
+        if( pTo->nCol!=nCol ){
+          bMismatch = 1;
+        }else{
+          int i;
+          for(i=0; i<nCol; i++){
+            if( pTo->abPK[i]!=abPK[i] ) bMismatch = 1;
+            if( sqlite3_stricmp(azCol[i], pTo->azCol[i]) ) bMismatch = 1;
+            if( abPK[i] ) bHasPk = 1;
+          }
+        }
+      }
+      sqlite3_free((char*)azCol);
+      if( bMismatch ){
+        if( pzErrMsg ){
+          *pzErrMsg = sqlite3_mprintf("table schemas do not match");
+        }
+        rc = SQLITE_SCHEMA;
+      }
+      if( bHasPk==0 ){
+        /* Ignore tables with no primary keys */
+        goto diff_out;
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      zExpr = sessionExprComparePK(pTo->nCol,
+          zDb, zFrom, pTo->zName, pTo->azCol, pTo->abPK
+      );
+    }
+
+    /* Find new rows */
+    if( rc==SQLITE_OK ){
+      rc = sessionDiffFindNew(SQLITE_INSERT, pSession, pTo, zDb, zFrom, zExpr);
+    }
+
+    /* Find old rows */
+    if( rc==SQLITE_OK ){
+      rc = sessionDiffFindNew(SQLITE_DELETE, pSession, pTo, zFrom, zDb, zExpr);
+    }
+
+    /* Find modified rows */
+    if( rc==SQLITE_OK ){
+      rc = sessionDiffFindModified(pSession, pTo, zFrom, zExpr);
+    }
+
+    sqlite3_free(zExpr);
+  }
+
+ diff_out:
+  sessionPreupdateHooks(pSession);
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+  return rc;
+}
+
+/*
+** Create a session object. This session object will record changes to
+** database zDb attached to connection db.
+*/
+SQLITE_API int sqlite3session_create(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of db (e.g. "main") */
+  sqlite3_session **ppSession     /* OUT: New session object */
+){
+  sqlite3_session *pNew;          /* Newly allocated session object */
+  sqlite3_session *pOld;          /* Session object already attached to db */
+  int nDb = sqlite3Strlen30(zDb); /* Length of zDb in bytes */
+
+  /* Zero the output value in case an error occurs. */
+  *ppSession = 0;
+
+  /* Allocate and populate the new session object. */
+  pNew = (sqlite3_session *)sqlite3_malloc64(sizeof(sqlite3_session) + nDb + 1);
+  if( !pNew ) return SQLITE_NOMEM;
+  memset(pNew, 0, sizeof(sqlite3_session));
+  pNew->db = db;
+  pNew->zDb = (char *)&pNew[1];
+  pNew->bEnable = 1;
+  memcpy(pNew->zDb, zDb, nDb+1);
+  sessionPreupdateHooks(pNew);
+
+  /* Add the new session object to the linked list of session objects
+  ** attached to database handle $db. Do this under the cover of the db
+  ** handle mutex.  */
+  sqlite3_mutex_enter(sqlite3_db_mutex(db));
+  pOld = (sqlite3_session*)sqlite3_preupdate_hook(db, xPreUpdate, (void*)pNew);
+  pNew->pNext = pOld;
+  sqlite3_mutex_leave(sqlite3_db_mutex(db));
+
+  *ppSession = pNew;
+  return SQLITE_OK;
+}
+
+/*
+** Free the list of table objects passed as the first argument. The contents
+** of the changed-rows hash tables are also deleted.
+*/
+static void sessionDeleteTable(sqlite3_session *pSession, SessionTable *pList){
+  SessionTable *pNext;
+  SessionTable *pTab;
+
+  for(pTab=pList; pTab; pTab=pNext){
+    int i;
+    pNext = pTab->pNext;
+    for(i=0; i<pTab->nChange; i++){
+      SessionChange *p;
+      SessionChange *pNextChange;
+      for(p=pTab->apChange[i]; p; p=pNextChange){
+        pNextChange = p->pNext;
+        sessionFree(pSession, p);
+      }
+    }
+    sqlite3_finalize(pTab->pDfltStmt);
+    sessionFree(pSession, (char*)pTab->azCol);  /* cast works around VC++ bug */
+    sessionFree(pSession, pTab->apChange);
+    sessionFree(pSession, pTab);
+  }
+}
+
+/*
+** Delete a session object previously allocated using sqlite3session_create().
+*/
+SQLITE_API void sqlite3session_delete(sqlite3_session *pSession){
+  sqlite3 *db = pSession->db;
+  sqlite3_session *pHead;
+  sqlite3_session **pp;
+
+  /* Unlink the session from the linked list of sessions attached to the
+  ** database handle. Hold the db mutex while doing so.  */
+  sqlite3_mutex_enter(sqlite3_db_mutex(db));
+  pHead = (sqlite3_session*)sqlite3_preupdate_hook(db, 0, 0);
+  for(pp=&pHead; ALWAYS((*pp)!=0); pp=&((*pp)->pNext)){
+    if( (*pp)==pSession ){
+      *pp = (*pp)->pNext;
+      if( pHead ) sqlite3_preupdate_hook(db, xPreUpdate, (void*)pHead);
+      break;
+    }
+  }
+  sqlite3_mutex_leave(sqlite3_db_mutex(db));
+  sqlite3ValueFree(pSession->pZeroBlob);
+
+  /* Delete all attached table objects. And the contents of their
+  ** associated hash-tables. */
+  sessionDeleteTable(pSession, pSession->pTable);
+
+  /* Free the session object. */
+  sqlite3_free(pSession);
+}
+
+/*
+** Set a table filter on a Session Object.
+*/
+SQLITE_API void sqlite3session_table_filter(
+  sqlite3_session *pSession,
+  int(*xFilter)(void*, const char*),
+  void *pCtx                      /* First argument passed to xFilter */
+){
+  pSession->bAutoAttach = 1;
+  pSession->pFilterCtx = pCtx;
+  pSession->xTableFilter = xFilter;
+}
+
+/*
+** Attach a table to a session. All subsequent changes made to the table
+** while the session object is enabled will be recorded.
+**
+** Only tables that have a PRIMARY KEY defined may be attached. It does
+** not matter if the PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias)
+** or not.
+*/
+SQLITE_API int sqlite3session_attach(
+  sqlite3_session *pSession,      /* Session object */
+  const char *zName               /* Table name */
+){
+  int rc = SQLITE_OK;
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+
+  if( !zName ){
+    pSession->bAutoAttach = 1;
+  }else{
+    SessionTable *pTab;           /* New table object (if required) */
+    int nName;                    /* Number of bytes in string zName */
+
+    /* First search for an existing entry. If one is found, this call is
+    ** a no-op. Return early. */
+    nName = sqlite3Strlen30(zName);
+    for(pTab=pSession->pTable; pTab; pTab=pTab->pNext){
+      if( 0==sqlite3_strnicmp(pTab->zName, zName, nName+1) ) break;
+    }
+
+    if( !pTab ){
+      /* Allocate new SessionTable object. */
+      int nByte = sizeof(SessionTable) + nName + 1;
+      pTab = (SessionTable*)sessionMalloc64(pSession, nByte);
+      if( !pTab ){
+        rc = SQLITE_NOMEM;
+      }else{
+        /* Populate the new SessionTable object and link it into the list.
+        ** The new object must be linked onto the end of the list, not
+        ** simply added to the start of it in order to ensure that tables
+        ** appear in the correct order when a changeset or patchset is
+        ** eventually generated. */
+        SessionTable **ppTab;
+        memset(pTab, 0, sizeof(SessionTable));
+        pTab->zName = (char *)&pTab[1];
+        memcpy(pTab->zName, zName, nName+1);
+        for(ppTab=&pSession->pTable; *ppTab; ppTab=&(*ppTab)->pNext);
+        *ppTab = pTab;
+      }
+    }
+  }
+
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+  return rc;
+}
+
+/*
+** Append the value passed as the second argument to the buffer passed
+** as the first.
+**
+** This function is a no-op if *pRc is non-zero when it is called.
+** Otherwise, if an error occurs, *pRc is set to an SQLite error code
+** before returning.
+*/
+static void sessionAppendValue(SessionBuffer *p, sqlite3_value *pVal, int *pRc){
+  int rc = *pRc;
+  if( rc==SQLITE_OK ){
+    sqlite3_int64 nByte = 0;
+    rc = sessionSerializeValue(0, pVal, &nByte);
+    sessionBufferGrow(p, nByte, &rc);
+    if( rc==SQLITE_OK ){
+      rc = sessionSerializeValue(&p->aBuf[p->nBuf], pVal, 0);
+      p->nBuf += nByte;
+    }else{
+      *pRc = rc;
+    }
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append a single byte to the buffer.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendByte(SessionBuffer *p, u8 v, int *pRc){
+  if( 0==sessionBufferGrow(p, 1, pRc) ){
+    p->aBuf[p->nBuf++] = v;
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append a single varint to the buffer.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendVarint(SessionBuffer *p, int v, int *pRc){
+  if( 0==sessionBufferGrow(p, 9, pRc) ){
+    p->nBuf += sessionVarintPut(&p->aBuf[p->nBuf], v);
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append a blob of data to the buffer.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendBlob(
+  SessionBuffer *p,
+  const u8 *aBlob,
+  int nBlob,
+  int *pRc
+){
+  if( nBlob>0 && 0==sessionBufferGrow(p, nBlob, pRc) ){
+    memcpy(&p->aBuf[p->nBuf], aBlob, nBlob);
+    p->nBuf += nBlob;
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append the string representation of integer iVal
+** to the buffer. No nul-terminator is written.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendInteger(
+  SessionBuffer *p,               /* Buffer to append to */
+  int iVal,                       /* Value to write the string rep. of */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  char aBuf[24];
+  sqlite3_snprintf(sizeof(aBuf)-1, aBuf, "%d", iVal);
+  sessionAppendStr(p, aBuf, pRc);
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append the string zStr enclosed in quotes (") and
+** with any embedded quote characters escaped to the buffer. No
+** nul-terminator byte is written.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendIdent(
+  SessionBuffer *p,               /* Buffer to a append to */
+  const char *zStr,               /* String to quote, escape and append */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  int nStr = sqlite3Strlen30(zStr)*2 + 2 + 2;
+  if( 0==sessionBufferGrow(p, nStr, pRc) ){
+    char *zOut = (char *)&p->aBuf[p->nBuf];
+    const char *zIn = zStr;
+    *zOut++ = '"';
+    if( zIn!=0 ){
+      while( *zIn ){
+        if( *zIn=='"' ) *zOut++ = '"';
+        *zOut++ = *(zIn++);
+      }
+    }
+    *zOut++ = '"';
+    p->nBuf = (int)((u8 *)zOut - p->aBuf);
+    p->aBuf[p->nBuf] = 0x00;
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwse, it appends the serialized version of the value stored
+** in column iCol of the row that SQL statement pStmt currently points
+** to to the buffer.
+*/
+static void sessionAppendCol(
+  SessionBuffer *p,               /* Buffer to append to */
+  sqlite3_stmt *pStmt,            /* Handle pointing to row containing value */
+  int iCol,                       /* Column to read value from */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( *pRc==SQLITE_OK ){
+    int eType = sqlite3_column_type(pStmt, iCol);
+    sessionAppendByte(p, (u8)eType, pRc);
+    if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+      sqlite3_int64 i;
+      u8 aBuf[8];
+      if( eType==SQLITE_INTEGER ){
+        i = sqlite3_column_int64(pStmt, iCol);
+      }else{
+        double r = sqlite3_column_double(pStmt, iCol);
+        memcpy(&i, &r, 8);
+      }
+      sessionPutI64(aBuf, i);
+      sessionAppendBlob(p, aBuf, 8, pRc);
+    }
+    if( eType==SQLITE_BLOB || eType==SQLITE_TEXT ){
+      u8 *z;
+      int nByte;
+      if( eType==SQLITE_BLOB ){
+        z = (u8 *)sqlite3_column_blob(pStmt, iCol);
+      }else{
+        z = (u8 *)sqlite3_column_text(pStmt, iCol);
+      }
+      nByte = sqlite3_column_bytes(pStmt, iCol);
+      if( z || (eType==SQLITE_BLOB && nByte==0) ){
+        sessionAppendVarint(p, nByte, pRc);
+        sessionAppendBlob(p, z, nByte, pRc);
+      }else{
+        *pRc = SQLITE_NOMEM;
+      }
+    }
+  }
+}
+
+/*
+**
+** This function appends an update change to the buffer (see the comments
+** under "CHANGESET FORMAT" at the top of the file). An update change
+** consists of:
+**
+**   1 byte:  SQLITE_UPDATE (0x17)
+**   n bytes: old.* record (see RECORD FORMAT)
+**   m bytes: new.* record (see RECORD FORMAT)
+**
+** The SessionChange object passed as the third argument contains the
+** values that were stored in the row when the session began (the old.*
+** values). The statement handle passed as the second argument points
+** at the current version of the row (the new.* values).
+**
+** If all of the old.* values are equal to their corresponding new.* value
+** (i.e. nothing has changed), then no data at all is appended to the buffer.
+**
+** Otherwise, the old.* record contains all primary key values and the
+** original values of any fields that have been modified. The new.* record
+** contains the new values of only those fields that have been modified.
+*/
+static int sessionAppendUpdate(
+  SessionBuffer *pBuf,            /* Buffer to append to */
+  int bPatchset,                  /* True for "patchset", 0 for "changeset" */
+  sqlite3_stmt *pStmt,            /* Statement handle pointing at new row */
+  SessionChange *p,               /* Object containing old values */
+  u8 *abPK                        /* Boolean array - true for PK columns */
+){
+  int rc = SQLITE_OK;
+  SessionBuffer buf2 = {0,0,0}; /* Buffer to accumulate new.* record in */
+  int bNoop = 1;                /* Set to zero if any values are modified */
+  int nRewind = pBuf->nBuf;     /* Set to zero if any values are modified */
+  int i;                        /* Used to iterate through columns */
+  u8 *pCsr = p->aRecord;        /* Used to iterate through old.* values */
+
+  assert( abPK!=0 );
+  sessionAppendByte(pBuf, SQLITE_UPDATE, &rc);
+  sessionAppendByte(pBuf, p->bIndirect, &rc);
+  for(i=0; i<sqlite3_column_count(pStmt); i++){
+    int bChanged = 0;
+    int nAdvance;
+    int eType = *pCsr;
+    switch( eType ){
+      case SQLITE_NULL:
+        nAdvance = 1;
+        if( sqlite3_column_type(pStmt, i)!=SQLITE_NULL ){
+          bChanged = 1;
+        }
+        break;
+
+      case SQLITE_FLOAT:
+      case SQLITE_INTEGER: {
+        nAdvance = 9;
+        if( eType==sqlite3_column_type(pStmt, i) ){
+          sqlite3_int64 iVal = sessionGetI64(&pCsr[1]);
+          if( eType==SQLITE_INTEGER ){
+            if( iVal==sqlite3_column_int64(pStmt, i) ) break;
+          }else{
+            double dVal;
+            memcpy(&dVal, &iVal, 8);
+            if( dVal==sqlite3_column_double(pStmt, i) ) break;
+          }
+        }
+        bChanged = 1;
+        break;
+      }
+
+      default: {
+        int n;
+        int nHdr = 1 + sessionVarintGet(&pCsr[1], &n);
+        assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
+        nAdvance = nHdr + n;
+        if( eType==sqlite3_column_type(pStmt, i)
+         && n==sqlite3_column_bytes(pStmt, i)
+         && (n==0 || 0==memcmp(&pCsr[nHdr], sqlite3_column_blob(pStmt, i), n))
+        ){
+          break;
+        }
+        bChanged = 1;
+      }
+    }
+
+    /* If at least one field has been modified, this is not a no-op. */
+    if( bChanged ) bNoop = 0;
+
+    /* Add a field to the old.* record. This is omitted if this module is
+    ** currently generating a patchset. */
+    if( bPatchset==0 ){
+      if( bChanged || abPK[i] ){
+        sessionAppendBlob(pBuf, pCsr, nAdvance, &rc);
+      }else{
+        sessionAppendByte(pBuf, 0, &rc);
+      }
+    }
+
+    /* Add a field to the new.* record. Or the only record if currently
+    ** generating a patchset.  */
+    if( bChanged || (bPatchset && abPK[i]) ){
+      sessionAppendCol(&buf2, pStmt, i, &rc);
+    }else{
+      sessionAppendByte(&buf2, 0, &rc);
+    }
+
+    pCsr += nAdvance;
+  }
+
+  if( bNoop ){
+    pBuf->nBuf = nRewind;
+  }else{
+    sessionAppendBlob(pBuf, buf2.aBuf, buf2.nBuf, &rc);
+  }
+  sqlite3_free(buf2.aBuf);
+
+  return rc;
+}
+
+/*
+** Append a DELETE change to the buffer passed as the first argument. Use
+** the changeset format if argument bPatchset is zero, or the patchset
+** format otherwise.
+*/
+static int sessionAppendDelete(
+  SessionBuffer *pBuf,            /* Buffer to append to */
+  int bPatchset,                  /* True for "patchset", 0 for "changeset" */
+  SessionChange *p,               /* Object containing old values */
+  int nCol,                       /* Number of columns in table */
+  u8 *abPK                        /* Boolean array - true for PK columns */
+){
+  int rc = SQLITE_OK;
+
+  sessionAppendByte(pBuf, SQLITE_DELETE, &rc);
+  sessionAppendByte(pBuf, p->bIndirect, &rc);
+
+  if( bPatchset==0 ){
+    sessionAppendBlob(pBuf, p->aRecord, p->nRecord, &rc);
+  }else{
+    int i;
+    u8 *a = p->aRecord;
+    for(i=0; i<nCol; i++){
+      u8 *pStart = a;
+      int eType = *a++;
+
+      switch( eType ){
+        case 0:
+        case SQLITE_NULL:
+          assert( abPK[i]==0 );
+          break;
+
+        case SQLITE_FLOAT:
+        case SQLITE_INTEGER:
+          a += 8;
+          break;
+
+        default: {
+          int n;
+          a += sessionVarintGet(a, &n);
+          a += n;
+          break;
+        }
+      }
+      if( abPK[i] ){
+        sessionAppendBlob(pBuf, pStart, (int)(a-pStart), &rc);
+      }
+    }
+    assert( (a - p->aRecord)==p->nRecord );
+  }
+
+  return rc;
+}
+
+/*
+** Formulate and prepare a SELECT statement to retrieve a row from table
+** zTab in database zDb based on its primary key. i.e.
+**
+**   SELECT *, <noop-test> FROM zDb.zTab WHERE (pk1, pk2,...) IS (?1, ?2,...)
+**
+** where <noop-test> is:
+**
+**   1 AND (?A OR ?1 IS <column>) AND ...
+**
+** for each non-pk <column>.
+*/
+static int sessionSelectStmt(
+  sqlite3 *db,                    /* Database handle */
+  int bIgnoreNoop,
+  const char *zDb,                /* Database name */
+  const char *zTab,               /* Table name */
+  int bRowid,
+  int nCol,                       /* Number of columns in table */
+  const char **azCol,             /* Names of table columns */
+  u8 *abPK,                       /* PRIMARY KEY  array */
+  sqlite3_stmt **ppStmt           /* OUT: Prepared SELECT statement */
+){
+  int rc = SQLITE_OK;
+  char *zSql = 0;
+  const char *zSep = "";
+  int nSql = -1;
+  int i;
+
+  SessionBuffer cols = {0, 0, 0};
+  SessionBuffer nooptest = {0, 0, 0};
+  SessionBuffer pkfield = {0, 0, 0};
+  SessionBuffer pkvar = {0, 0, 0};
+
+  sessionAppendStr(&nooptest, ", 1", &rc);
+
+  if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){
+    sessionAppendStr(&nooptest, " AND (?6 OR ?3 IS stat)", &rc);
+    sessionAppendStr(&pkfield, "tbl, idx", &rc);
+    sessionAppendStr(&pkvar,
+        "?1, (CASE WHEN ?2=X'' THEN NULL ELSE ?2 END)", &rc
+    );
+    sessionAppendStr(&cols, "tbl, ?2, stat", &rc);
+  }else{
+  #if 0
+    if( bRowid ){
+      sessionAppendStr(&cols, SESSIONS_ROWID, &rc);
+    }
+    #endif
+    for(i=0; i<nCol; i++){
+      if( cols.nBuf ) sessionAppendStr(&cols, ", ", &rc);
+      sessionAppendIdent(&cols, azCol[i], &rc);
+      if( abPK[i] ){
+        sessionAppendStr(&pkfield, zSep, &rc);
+        sessionAppendStr(&pkvar, zSep, &rc);
+        zSep = ", ";
+        sessionAppendIdent(&pkfield, azCol[i], &rc);
+        sessionAppendPrintf(&pkvar, &rc, "?%d", i+1);
+      }else{
+        sessionAppendPrintf(&nooptest, &rc,
+            " AND (?%d OR ?%d IS %w.%w)", i+1+nCol, i+1, zTab, azCol[i]
+        );
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    zSql = sqlite3_mprintf(
+        "SELECT %s%s FROM %Q.%Q WHERE (%s) IS (%s)",
+        (char*)cols.aBuf, (bIgnoreNoop ? (char*)nooptest.aBuf : ""),
+        zDb, zTab, (char*)pkfield.aBuf, (char*)pkvar.aBuf
+    );
+    if( zSql==0 ) rc = SQLITE_NOMEM;
+  }
+
+#if 0
+  if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){
+    zSql = sqlite3_mprintf(
+        "SELECT tbl, ?2, stat FROM %Q.sqlite_stat1 WHERE tbl IS ?1 AND "
+        "idx IS (CASE WHEN ?2=X'' THEN NULL ELSE ?2 END)", zDb
+    );
+    if( zSql==0 ) rc = SQLITE_NOMEM;
+  }else{
+    const char *zSep = "";
+    SessionBuffer buf = {0, 0, 0};
+
+    sessionAppendStr(&buf, "SELECT * FROM ", &rc);
+    sessionAppendIdent(&buf, zDb, &rc);
+    sessionAppendStr(&buf, ".", &rc);
+    sessionAppendIdent(&buf, zTab, &rc);
+    sessionAppendStr(&buf, " WHERE ", &rc);
+    for(i=0; i<nCol; i++){
+      if( abPK[i] ){
+        sessionAppendStr(&buf, zSep, &rc);
+        sessionAppendIdent(&buf, azCol[i], &rc);
+        sessionAppendStr(&buf, " IS ?", &rc);
+        sessionAppendInteger(&buf, i+1, &rc);
+        zSep = " AND ";
+      }
+    }
+    zSql = (char*)buf.aBuf;
+    nSql = buf.nBuf;
+  }
+#endif
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_prepare_v2(db, zSql, nSql, ppStmt, 0);
+  }
+  sqlite3_free(zSql);
+  sqlite3_free(nooptest.aBuf);
+  sqlite3_free(pkfield.aBuf);
+  sqlite3_free(pkvar.aBuf);
+  sqlite3_free(cols.aBuf);
+  return rc;
+}
+
+/*
+** Bind the PRIMARY KEY values from the change passed in argument pChange
+** to the SELECT statement passed as the first argument. The SELECT statement
+** is as prepared by function sessionSelectStmt().
+**
+** Return SQLITE_OK if all PK values are successfully bound, or an SQLite
+** error code (e.g. SQLITE_NOMEM) otherwise.
+*/
+static int sessionSelectBind(
+  sqlite3_stmt *pSelect,          /* SELECT from sessionSelectStmt() */
+  int nCol,                       /* Number of columns in table */
+  u8 *abPK,                       /* PRIMARY KEY array */
+  SessionChange *pChange          /* Change structure */
+){
+  int i;
+  int rc = SQLITE_OK;
+  u8 *a = pChange->aRecord;
+
+  for(i=0; i<nCol && rc==SQLITE_OK; i++){
+    int eType = *a++;
+
+    switch( eType ){
+      case 0:
+      case SQLITE_NULL:
+        assert( abPK[i]==0 );
+        break;
+
+      case SQLITE_INTEGER: {
+        if( abPK[i] ){
+          i64 iVal = sessionGetI64(a);
+          rc = sqlite3_bind_int64(pSelect, i+1, iVal);
+        }
+        a += 8;
+        break;
+      }
+
+      case SQLITE_FLOAT: {
+        if( abPK[i] ){
+          double rVal;
+          i64 iVal = sessionGetI64(a);
+          memcpy(&rVal, &iVal, 8);
+          rc = sqlite3_bind_double(pSelect, i+1, rVal);
+        }
+        a += 8;
+        break;
+      }
+
+      case SQLITE_TEXT: {
+        int n;
+        a += sessionVarintGet(a, &n);
+        if( abPK[i] ){
+          rc = sqlite3_bind_text(pSelect, i+1, (char *)a, n, SQLITE_TRANSIENT);
+        }
+        a += n;
+        break;
+      }
+
+      default: {
+        int n;
+        assert( eType==SQLITE_BLOB );
+        a += sessionVarintGet(a, &n);
+        if( abPK[i] ){
+          rc = sqlite3_bind_blob(pSelect, i+1, a, n, SQLITE_TRANSIENT);
+        }
+        a += n;
+        break;
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is a no-op if *pRc is set to other than SQLITE_OK when it
+** is called. Otherwise, append a serialized table header (part of the binary
+** changeset format) to buffer *pBuf. If an error occurs, set *pRc to an
+** SQLite error code before returning.
+*/
+static void sessionAppendTableHdr(
+  SessionBuffer *pBuf,            /* Append header to this buffer */
+  int bPatchset,                  /* Use the patchset format if true */
+  SessionTable *pTab,             /* Table object to append header for */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  /* Write a table header */
+  sessionAppendByte(pBuf, (bPatchset ? 'P' : 'T'), pRc);
+  sessionAppendVarint(pBuf, pTab->nCol, pRc);
+  sessionAppendBlob(pBuf, pTab->abPK, pTab->nCol, pRc);
+  sessionAppendBlob(pBuf, (u8 *)pTab->zName, (int)strlen(pTab->zName)+1, pRc);
+}
+
+/*
+** Generate either a changeset (if argument bPatchset is zero) or a patchset
+** (if it is non-zero) based on the current contents of the session object
+** passed as the first argument.
+**
+** If no error occurs, SQLITE_OK is returned and the new changeset/patchset
+** stored in output variables *pnChangeset and *ppChangeset. Or, if an error
+** occurs, an SQLite error code is returned and both output variables set
+** to 0.
+*/
+static int sessionGenerateChangeset(
+  sqlite3_session *pSession,      /* Session object */
+  int bPatchset,                  /* True for patchset, false for changeset */
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut,                     /* First argument for xOutput */
+  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
+  void **ppChangeset              /* OUT: Buffer containing changeset */
+){
+  sqlite3 *db = pSession->db;     /* Source database handle */
+  SessionTable *pTab;             /* Used to iterate through attached tables */
+  SessionBuffer buf = {0,0,0};    /* Buffer in which to accumlate changeset */
+  int rc;                         /* Return code */
+
+  assert( xOutput==0 || (pnChangeset==0 && ppChangeset==0) );
+  assert( xOutput!=0 || (pnChangeset!=0 && ppChangeset!=0) );
+
+  /* Zero the output variables in case an error occurs. If this session
+  ** object is already in the error state (sqlite3_session.rc != SQLITE_OK),
+  ** this call will be a no-op.  */
+  if( xOutput==0 ){
+    assert( pnChangeset!=0  && ppChangeset!=0 );
+    *pnChangeset = 0;
+    *ppChangeset = 0;
+  }
+
+  if( pSession->rc ) return pSession->rc;
+  rc = sqlite3_exec(pSession->db, "SAVEPOINT changeset", 0, 0, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  sqlite3_mutex_enter(sqlite3_db_mutex(db));
+
+  for(pTab=pSession->pTable; rc==SQLITE_OK && pTab; pTab=pTab->pNext){
+    if( pTab->nEntry ){
+      const char *zName = pTab->zName;
+      int i;                      /* Used to iterate through hash buckets */
+      sqlite3_stmt *pSel = 0;     /* SELECT statement to query table pTab */
+      int nRewind = buf.nBuf;     /* Initial size of write buffer */
+      int nNoop;                  /* Size of buffer after writing tbl header */
+      int nOldCol = pTab->nCol;
+
+      /* Check the table schema is still Ok. */
+      rc = sessionReinitTable(pSession, pTab);
+      if( rc==SQLITE_OK && pTab->nCol!=nOldCol ){
+        rc = sessionUpdateChanges(pSession, pTab);
+      }
+
+      /* Write a table header */
+      sessionAppendTableHdr(&buf, bPatchset, pTab, &rc);
+
+      /* Build and compile a statement to execute: */
+      if( rc==SQLITE_OK ){
+        rc = sessionSelectStmt(db, 0, pSession->zDb,
+            zName, pTab->bRowid, pTab->nCol, pTab->azCol, pTab->abPK, &pSel
+        );
+      }
+
+      nNoop = buf.nBuf;
+      for(i=0; i<pTab->nChange && rc==SQLITE_OK; i++){
+        SessionChange *p;         /* Used to iterate through changes */
+
+        for(p=pTab->apChange[i]; rc==SQLITE_OK && p; p=p->pNext){
+          rc = sessionSelectBind(pSel, pTab->nCol, pTab->abPK, p);
+          if( rc!=SQLITE_OK ) continue;
+          if( sqlite3_step(pSel)==SQLITE_ROW ){
+            if( p->op==SQLITE_INSERT ){
+              int iCol;
+              sessionAppendByte(&buf, SQLITE_INSERT, &rc);
+              sessionAppendByte(&buf, p->bIndirect, &rc);
+              for(iCol=0; iCol<pTab->nCol; iCol++){
+                sessionAppendCol(&buf, pSel, iCol, &rc);
+              }
+            }else{
+              assert( pTab->abPK!=0 );
+              rc = sessionAppendUpdate(&buf, bPatchset, pSel, p, pTab->abPK);
+            }
+          }else if( p->op!=SQLITE_INSERT ){
+            rc = sessionAppendDelete(&buf, bPatchset, p, pTab->nCol,pTab->abPK);
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3_reset(pSel);
+          }
+
+          /* If the buffer is now larger than sessions_strm_chunk_size, pass
+          ** its contents to the xOutput() callback. */
+          if( xOutput
+           && rc==SQLITE_OK
+           && buf.nBuf>nNoop
+           && buf.nBuf>sessions_strm_chunk_size
+          ){
+            rc = xOutput(pOut, (void*)buf.aBuf, buf.nBuf);
+            nNoop = -1;
+            buf.nBuf = 0;
+          }
+
+        }
+      }
+
+      sqlite3_finalize(pSel);
+      if( buf.nBuf==nNoop ){
+        buf.nBuf = nRewind;
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( xOutput==0 ){
+      *pnChangeset = buf.nBuf;
+      *ppChangeset = buf.aBuf;
+      buf.aBuf = 0;
+    }else if( buf.nBuf>0 ){
+      rc = xOutput(pOut, (void*)buf.aBuf, buf.nBuf);
+    }
+  }
+
+  sqlite3_free(buf.aBuf);
+  sqlite3_exec(db, "RELEASE changeset", 0, 0, 0);
+  sqlite3_mutex_leave(sqlite3_db_mutex(db));
+  return rc;
+}
+
+/*
+** Obtain a changeset object containing all changes recorded by the
+** session object passed as the first argument.
+**
+** It is the responsibility of the caller to eventually free the buffer
+** using sqlite3_free().
+*/
+SQLITE_API int sqlite3session_changeset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
+  void **ppChangeset              /* OUT: Buffer containing changeset */
+){
+  int rc;
+
+  if( pnChangeset==0 || ppChangeset==0 ) return SQLITE_MISUSE;
+  rc = sessionGenerateChangeset(pSession, 0, 0, 0, pnChangeset, ppChangeset);
+  assert( rc || pnChangeset==0
+       || pSession->bEnableSize==0 || *pnChangeset<=pSession->nMaxChangesetSize
+  );
+  return rc;
+}
+
+/*
+** Streaming version of sqlite3session_changeset().
+*/
+SQLITE_API int sqlite3session_changeset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  if( xOutput==0 ) return SQLITE_MISUSE;
+  return sessionGenerateChangeset(pSession, 0, xOutput, pOut, 0, 0);
+}
+
+/*
+** Streaming version of sqlite3session_patchset().
+*/
+SQLITE_API int sqlite3session_patchset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  if( xOutput==0 ) return SQLITE_MISUSE;
+  return sessionGenerateChangeset(pSession, 1, xOutput, pOut, 0, 0);
+}
+
+/*
+** Obtain a patchset object containing all changes recorded by the
+** session object passed as the first argument.
+**
+** It is the responsibility of the caller to eventually free the buffer
+** using sqlite3_free().
+*/
+SQLITE_API int sqlite3session_patchset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnPatchset,                /* OUT: Size of buffer at *ppChangeset */
+  void **ppPatchset               /* OUT: Buffer containing changeset */
+){
+  if( pnPatchset==0 || ppPatchset==0 ) return SQLITE_MISUSE;
+  return sessionGenerateChangeset(pSession, 1, 0, 0, pnPatchset, ppPatchset);
+}
+
+/*
+** Enable or disable the session object passed as the first argument.
+*/
+SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable){
+  int ret;
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+  if( bEnable>=0 ){
+    pSession->bEnable = bEnable;
+  }
+  ret = pSession->bEnable;
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+  return ret;
+}
+
+/*
+** Enable or disable the session object passed as the first argument.
+*/
+SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect){
+  int ret;
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+  if( bIndirect>=0 ){
+    pSession->bIndirect = bIndirect;
+  }
+  ret = pSession->bIndirect;
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+  return ret;
+}
+
+/*
+** Return true if there have been no changes to monitored tables recorded
+** by the session object passed as the only argument.
+*/
+SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession){
+  int ret = 0;
+  SessionTable *pTab;
+
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+  for(pTab=pSession->pTable; pTab && ret==0; pTab=pTab->pNext){
+    ret = (pTab->nEntry>0);
+  }
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+
+  return (ret==0);
+}
+
+/*
+** Return the amount of heap memory in use.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession){
+  return pSession->nMalloc;
+}
+
+/*
+** Configure the session object passed as the first argument.
+*/
+SQLITE_API int sqlite3session_object_config(sqlite3_session *pSession, int op, void *pArg){
+  int rc = SQLITE_OK;
+  switch( op ){
+    case SQLITE_SESSION_OBJCONFIG_SIZE: {
+      int iArg = *(int*)pArg;
+      if( iArg>=0 ){
+        if( pSession->pTable ){
+          rc = SQLITE_MISUSE;
+        }else{
+          pSession->bEnableSize = (iArg!=0);
+        }
+      }
+      *(int*)pArg = pSession->bEnableSize;
+      break;
+    }
+
+    case SQLITE_SESSION_OBJCONFIG_ROWID: {
+      int iArg = *(int*)pArg;
+      if( iArg>=0 ){
+        if( pSession->pTable ){
+          rc = SQLITE_MISUSE;
+        }else{
+          pSession->bImplicitPK = (iArg!=0);
+        }
+      }
+      *(int*)pArg = pSession->bImplicitPK;
+      break;
+    }
+
+    default:
+      rc = SQLITE_MISUSE;
+  }
+
+  return rc;
+}
+
+/*
+** Return the maximum size of sqlite3session_changeset() output.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession){
+  return pSession->nMaxChangesetSize;
+}
+
+/*
+** Do the work for either sqlite3changeset_start() or start_strm().
+*/
+static int sessionChangesetStart(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int nChangeset,                 /* Size of buffer pChangeset in bytes */
+  void *pChangeset,               /* Pointer to buffer containing changeset */
+  int bInvert,                    /* True to invert changeset */
+  int bSkipEmpty                  /* True to skip empty UPDATE changes */
+){
+  sqlite3_changeset_iter *pRet;   /* Iterator to return */
+  int nByte;                      /* Number of bytes to allocate for iterator */
+
+  assert( xInput==0 || (pChangeset==0 && nChangeset==0) );
+
+  /* Zero the output variable in case an error occurs. */
+  *pp = 0;
+
+  /* Allocate and initialize the iterator structure. */
+  nByte = sizeof(sqlite3_changeset_iter);
+  pRet = (sqlite3_changeset_iter *)sqlite3_malloc(nByte);
+  if( !pRet ) return SQLITE_NOMEM;
+  memset(pRet, 0, sizeof(sqlite3_changeset_iter));
+  pRet->in.aData = (u8 *)pChangeset;
+  pRet->in.nData = nChangeset;
+  pRet->in.xInput = xInput;
+  pRet->in.pIn = pIn;
+  pRet->in.bEof = (xInput ? 0 : 1);
+  pRet->bInvert = bInvert;
+  pRet->bSkipEmpty = bSkipEmpty;
+
+  /* Populate the output variable and return success. */
+  *pp = pRet;
+  return SQLITE_OK;
+}
+
+/*
+** Create an iterator used to iterate through the contents of a changeset.
+*/
+SQLITE_API int sqlite3changeset_start(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int nChangeset,                 /* Size of buffer pChangeset in bytes */
+  void *pChangeset                /* Pointer to buffer containing changeset */
+){
+  return sessionChangesetStart(pp, 0, 0, nChangeset, pChangeset, 0, 0);
+}
+SQLITE_API int sqlite3changeset_start_v2(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int nChangeset,                 /* Size of buffer pChangeset in bytes */
+  void *pChangeset,               /* Pointer to buffer containing changeset */
+  int flags
+){
+  int bInvert = !!(flags & SQLITE_CHANGESETSTART_INVERT);
+  return sessionChangesetStart(pp, 0, 0, nChangeset, pChangeset, bInvert, 0);
+}
+
+/*
+** Streaming version of sqlite3changeset_start().
+*/
+SQLITE_API int sqlite3changeset_start_strm(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn
+){
+  return sessionChangesetStart(pp, xInput, pIn, 0, 0, 0, 0);
+}
+SQLITE_API int sqlite3changeset_start_v2_strm(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int flags
+){
+  int bInvert = !!(flags & SQLITE_CHANGESETSTART_INVERT);
+  return sessionChangesetStart(pp, xInput, pIn, 0, 0, bInvert, 0);
+}
+
+/*
+** If the SessionInput object passed as the only argument is a streaming
+** object and the buffer is full, discard some data to free up space.
+*/
+static void sessionDiscardData(SessionInput *pIn){
+  if( pIn->xInput && pIn->iNext>=sessions_strm_chunk_size ){
+    int nMove = pIn->buf.nBuf - pIn->iNext;
+    assert( nMove>=0 );
+    if( nMove>0 ){
+      memmove(pIn->buf.aBuf, &pIn->buf.aBuf[pIn->iNext], nMove);
+    }
+    pIn->buf.nBuf -= pIn->iNext;
+    pIn->iNext = 0;
+    pIn->nData = pIn->buf.nBuf;
+  }
+}
+
+/*
+** Ensure that there are at least nByte bytes available in the buffer. Or,
+** if there are not nByte bytes remaining in the input, that all available
+** data is in the buffer.
+**
+** Return an SQLite error code if an error occurs, or SQLITE_OK otherwise.
+*/
+static int sessionInputBuffer(SessionInput *pIn, int nByte){
+  int rc = SQLITE_OK;
+  if( pIn->xInput ){
+    while( !pIn->bEof && (pIn->iNext+nByte)>=pIn->nData && rc==SQLITE_OK ){
+      int nNew = sessions_strm_chunk_size;
+
+      if( pIn->bNoDiscard==0 ) sessionDiscardData(pIn);
+      if( SQLITE_OK==sessionBufferGrow(&pIn->buf, nNew, &rc) ){
+        rc = pIn->xInput(pIn->pIn, &pIn->buf.aBuf[pIn->buf.nBuf], &nNew);
+        if( nNew==0 ){
+          pIn->bEof = 1;
+        }else{
+          pIn->buf.nBuf += nNew;
+        }
+      }
+
+      pIn->aData = pIn->buf.aBuf;
+      pIn->nData = pIn->buf.nBuf;
+    }
+  }
+  return rc;
+}
+
+/*
+** When this function is called, *ppRec points to the start of a record
+** that contains nCol values. This function advances the pointer *ppRec
+** until it points to the byte immediately following that record.
+*/
+static void sessionSkipRecord(
+  u8 **ppRec,                     /* IN/OUT: Record pointer */
+  int nCol                        /* Number of values in record */
+){
+  u8 *aRec = *ppRec;
+  int i;
+  for(i=0; i<nCol; i++){
+    int eType = *aRec++;
+    if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
+      int nByte;
+      aRec += sessionVarintGet((u8*)aRec, &nByte);
+      aRec += nByte;
+    }else if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+      aRec += 8;
+    }
+  }
+
+  *ppRec = aRec;
+}
+
+/*
+** This function sets the value of the sqlite3_value object passed as the
+** first argument to a copy of the string or blob held in the aData[]
+** buffer. SQLITE_OK is returned if successful, or SQLITE_NOMEM if an OOM
+** error occurs.
+*/
+static int sessionValueSetStr(
+  sqlite3_value *pVal,            /* Set the value of this object */
+  u8 *aData,                      /* Buffer containing string or blob data */
+  int nData,                      /* Size of buffer aData[] in bytes */
+  u8 enc                          /* String encoding (0 for blobs) */
+){
+  /* In theory this code could just pass SQLITE_TRANSIENT as the final
+  ** argument to sqlite3ValueSetStr() and have the copy created
+  ** automatically. But doing so makes it difficult to detect any OOM
+  ** error. Hence the code to create the copy externally. */
+  u8 *aCopy = sqlite3_malloc64((sqlite3_int64)nData+1);
+  if( aCopy==0 ) return SQLITE_NOMEM;
+  memcpy(aCopy, aData, nData);
+  sqlite3ValueSetStr(pVal, nData, (char*)aCopy, enc, sqlite3_free);
+  return SQLITE_OK;
+}
+
+/*
+** Deserialize a single record from a buffer in memory. See "RECORD FORMAT"
+** for details.
+**
+** When this function is called, *paChange points to the start of the record
+** to deserialize. Assuming no error occurs, *paChange is set to point to
+** one byte after the end of the same record before this function returns.
+** If the argument abPK is NULL, then the record contains nCol values. Or,
+** if abPK is other than NULL, then the record contains only the PK fields
+** (in other words, it is a patchset DELETE record).
+**
+** If successful, each element of the apOut[] array (allocated by the caller)
+** is set to point to an sqlite3_value object containing the value read
+** from the corresponding position in the record. If that value is not
+** included in the record (i.e. because the record is part of an UPDATE change
+** and the field was not modified), the corresponding element of apOut[] is
+** set to NULL.
+**
+** It is the responsibility of the caller to free all sqlite_value structures
+** using sqlite3_free().
+**
+** If an error occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
+** The apOut[] array may have been partially populated in this case.
+*/
+static int sessionReadRecord(
+  SessionInput *pIn,              /* Input data */
+  int nCol,                       /* Number of values in record */
+  u8 *abPK,                       /* Array of primary key flags, or NULL */
+  sqlite3_value **apOut,          /* Write values to this array */
+  int *pbEmpty
+){
+  int i;                          /* Used to iterate through columns */
+  int rc = SQLITE_OK;
+
+  assert( pbEmpty==0 || *pbEmpty==0 );
+  if( pbEmpty ) *pbEmpty = 1;
+  for(i=0; i<nCol && rc==SQLITE_OK; i++){
+    int eType = 0;                /* Type of value (SQLITE_NULL, TEXT etc.) */
+    if( abPK && abPK[i]==0 ) continue;
+    rc = sessionInputBuffer(pIn, 9);
+    if( rc==SQLITE_OK ){
+      if( pIn->iNext>=pIn->nData ){
+        rc = SQLITE_CORRUPT_BKPT;
+      }else{
+        eType = pIn->aData[pIn->iNext++];
+        assert( apOut[i]==0 );
+        if( eType ){
+          if( pbEmpty ) *pbEmpty = 0;
+          apOut[i] = sqlite3ValueNew(0);
+          if( !apOut[i] ) rc = SQLITE_NOMEM;
+        }
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      u8 *aVal = &pIn->aData[pIn->iNext];
+      if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
+        int nByte;
+        pIn->iNext += sessionVarintGet(aVal, &nByte);
+        rc = sessionInputBuffer(pIn, nByte);
+        if( rc==SQLITE_OK ){
+          if( nByte<0 || nByte>pIn->nData-pIn->iNext ){
+            rc = SQLITE_CORRUPT_BKPT;
+          }else{
+            u8 enc = (eType==SQLITE_TEXT ? SQLITE_UTF8 : 0);
+            rc = sessionValueSetStr(apOut[i],&pIn->aData[pIn->iNext],nByte,enc);
+            pIn->iNext += nByte;
+          }
+        }
+      }
+      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+        if( (pIn->nData-pIn->iNext)<8 ){
+          rc = SQLITE_CORRUPT_BKPT;
+        }else{
+          sqlite3_int64 v = sessionGetI64(aVal);
+          if( eType==SQLITE_INTEGER ){
+            sqlite3VdbeMemSetInt64(apOut[i], v);
+          }else{
+            double d;
+            memcpy(&d, &v, 8);
+            sqlite3VdbeMemSetDouble(apOut[i], d);
+          }
+          pIn->iNext += 8;
+        }
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The input pointer currently points to the second byte of a table-header.
+** Specifically, to the following:
+**
+**   + number of columns in table (varint)
+**   + array of PK flags (1 byte per column),
+**   + table name (nul terminated).
+**
+** This function ensures that all of the above is present in the input
+** buffer (i.e. that it can be accessed without any calls to xInput()).
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+** The input pointer is not moved.
+*/
+static int sessionChangesetBufferTblhdr(SessionInput *pIn, int *pnByte){
+  int rc = SQLITE_OK;
+  int nCol = 0;
+  int nRead = 0;
+
+  rc = sessionInputBuffer(pIn, 9);
+  if( rc==SQLITE_OK ){
+    nRead += sessionVarintGet(&pIn->aData[pIn->iNext + nRead], &nCol);
+    /* The hard upper limit for the number of columns in an SQLite
+    ** database table is, according to sqliteLimit.h, 32676. So
+    ** consider any table-header that purports to have more than 65536
+    ** columns to be corrupt. This is convenient because otherwise,
+    ** if the (nCol>65536) condition below were omitted, a sufficiently
+    ** large value for nCol may cause nRead to wrap around and become
+    ** negative. Leading to a crash. */
+    if( nCol<0 || nCol>65536 ){
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      rc = sessionInputBuffer(pIn, nRead+nCol+100);
+      nRead += nCol;
+    }
+  }
+
+  while( rc==SQLITE_OK ){
+    while( (pIn->iNext + nRead)<pIn->nData && pIn->aData[pIn->iNext + nRead] ){
+      nRead++;
+    }
+    if( (pIn->iNext + nRead)<pIn->nData ) break;
+    rc = sessionInputBuffer(pIn, nRead + 100);
+  }
+  *pnByte = nRead+1;
+  return rc;
+}
+
+/*
+** The input pointer currently points to the first byte of the first field
+** of a record consisting of nCol columns. This function ensures the entire
+** record is buffered. It does not move the input pointer.
+**
+** If successful, SQLITE_OK is returned and *pnByte is set to the size of
+** the record in bytes. Otherwise, an SQLite error code is returned. The
+** final value of *pnByte is undefined in this case.
+*/
+static int sessionChangesetBufferRecord(
+  SessionInput *pIn,              /* Input data */
+  int nCol,                       /* Number of columns in record */
+  int *pnByte                     /* OUT: Size of record in bytes */
+){
+  int rc = SQLITE_OK;
+  int nByte = 0;
+  int i;
+  for(i=0; rc==SQLITE_OK && i<nCol; i++){
+    int eType;
+    rc = sessionInputBuffer(pIn, nByte + 10);
+    if( rc==SQLITE_OK ){
+      eType = pIn->aData[pIn->iNext + nByte++];
+      if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
+        int n;
+        nByte += sessionVarintGet(&pIn->aData[pIn->iNext+nByte], &n);
+        nByte += n;
+        rc = sessionInputBuffer(pIn, nByte);
+      }else if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+        nByte += 8;
+      }
+    }
+  }
+  *pnByte = nByte;
+  return rc;
+}
+
+/*
+** The input pointer currently points to the second byte of a table-header.
+** Specifically, to the following:
+**
+**   + number of columns in table (varint)
+**   + array of PK flags (1 byte per column),
+**   + table name (nul terminated).
+**
+** This function decodes the table-header and populates the p->nCol,
+** p->zTab and p->abPK[] variables accordingly. The p->apValue[] array is
+** also allocated or resized according to the new value of p->nCol. The
+** input pointer is left pointing to the byte following the table header.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code
+** is returned and the final values of the various fields enumerated above
+** are undefined.
+*/
+static int sessionChangesetReadTblhdr(sqlite3_changeset_iter *p){
+  int rc;
+  int nCopy;
+  assert( p->rc==SQLITE_OK );
+
+  rc = sessionChangesetBufferTblhdr(&p->in, &nCopy);
+  if( rc==SQLITE_OK ){
+    int nByte;
+    int nVarint;
+    nVarint = sessionVarintGet(&p->in.aData[p->in.iNext], &p->nCol);
+    if( p->nCol>0 ){
+      nCopy -= nVarint;
+      p->in.iNext += nVarint;
+      nByte = p->nCol * sizeof(sqlite3_value*) * 2 + nCopy;
+      p->tblhdr.nBuf = 0;
+      sessionBufferGrow(&p->tblhdr, nByte, &rc);
+    }else{
+      rc = SQLITE_CORRUPT_BKPT;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    size_t iPK = sizeof(sqlite3_value*)*p->nCol*2;
+    memset(p->tblhdr.aBuf, 0, iPK);
+    memcpy(&p->tblhdr.aBuf[iPK], &p->in.aData[p->in.iNext], nCopy);
+    p->in.iNext += nCopy;
+  }
+
+  p->apValue = (sqlite3_value**)p->tblhdr.aBuf;
+  if( p->apValue==0 ){
+    p->abPK = 0;
+    p->zTab = 0;
+  }else{
+    p->abPK = (u8*)&p->apValue[p->nCol*2];
+    p->zTab = p->abPK ? (char*)&p->abPK[p->nCol] : 0;
+  }
+  return (p->rc = rc);
+}
+
+/*
+** Advance the changeset iterator to the next change. The differences between
+** this function and sessionChangesetNext() are that
+**
+**   * If pbEmpty is not NULL and the change is a no-op UPDATE (an UPDATE
+**     that modifies no columns), this function sets (*pbEmpty) to 1.
+**
+**   * If the iterator is configured to skip no-op UPDATEs,
+**     sessionChangesetNext() does that. This function does not.
+*/
+static int sessionChangesetNextOne(
+  sqlite3_changeset_iter *p,      /* Changeset iterator */
+  u8 **paRec,                     /* If non-NULL, store record pointer here */
+  int *pnRec,                     /* If non-NULL, store size of record here */
+  int *pbNew,                     /* If non-NULL, true if new table */
+  int *pbEmpty
+){
+  int i;
+  u8 op;
+
+  assert( (paRec==0 && pnRec==0) || (paRec && pnRec) );
+  assert( pbEmpty==0 || *pbEmpty==0 );
+
+  /* If the iterator is in the error-state, return immediately. */
+  if( p->rc!=SQLITE_OK ) return p->rc;
+
+  /* Free the current contents of p->apValue[], if any. */
+  if( p->apValue ){
+    for(i=0; i<p->nCol*2; i++){
+      sqlite3ValueFree(p->apValue[i]);
+    }
+    memset(p->apValue, 0, sizeof(sqlite3_value*)*p->nCol*2);
+  }
+
+  /* Make sure the buffer contains at least 10 bytes of input data, or all
+  ** remaining data if there are less than 10 bytes available. This is
+  ** sufficient either for the 'T' or 'P' byte and the varint that follows
+  ** it, or for the two single byte values otherwise. */
+  p->rc = sessionInputBuffer(&p->in, 2);
+  if( p->rc!=SQLITE_OK ) return p->rc;
+
+  sessionDiscardData(&p->in);
+  p->in.iCurrent = p->in.iNext;
+
+  /* If the iterator is already at the end of the changeset, return DONE. */
+  if( p->in.iNext>=p->in.nData ){
+    return SQLITE_DONE;
+  }
+
+  op = p->in.aData[p->in.iNext++];
+  while( op=='T' || op=='P' ){
+    if( pbNew ) *pbNew = 1;
+    p->bPatchset = (op=='P');
+    if( sessionChangesetReadTblhdr(p) ) return p->rc;
+    if( (p->rc = sessionInputBuffer(&p->in, 2)) ) return p->rc;
+    p->in.iCurrent = p->in.iNext;
+    if( p->in.iNext>=p->in.nData ) return SQLITE_DONE;
+    op = p->in.aData[p->in.iNext++];
+  }
+
+  if( p->zTab==0 || (p->bPatchset && p->bInvert) ){
+    /* The first record in the changeset is not a table header. Must be a
+    ** corrupt changeset. */
+    assert( p->in.iNext==1 || p->zTab );
+    return (p->rc = SQLITE_CORRUPT_BKPT);
+  }
+
+  p->op = op;
+  p->bIndirect = p->in.aData[p->in.iNext++];
+  if( p->op!=SQLITE_UPDATE && p->op!=SQLITE_DELETE && p->op!=SQLITE_INSERT ){
+    return (p->rc = SQLITE_CORRUPT_BKPT);
+  }
+
+  if( paRec ){
+    int nVal;                     /* Number of values to buffer */
+    if( p->bPatchset==0 && op==SQLITE_UPDATE ){
+      nVal = p->nCol * 2;
+    }else if( p->bPatchset && op==SQLITE_DELETE ){
+      nVal = 0;
+      for(i=0; i<p->nCol; i++) if( p->abPK[i] ) nVal++;
+    }else{
+      nVal = p->nCol;
+    }
+    p->rc = sessionChangesetBufferRecord(&p->in, nVal, pnRec);
+    if( p->rc!=SQLITE_OK ) return p->rc;
+    *paRec = &p->in.aData[p->in.iNext];
+    p->in.iNext += *pnRec;
+  }else{
+    sqlite3_value **apOld = (p->bInvert ? &p->apValue[p->nCol] : p->apValue);
+    sqlite3_value **apNew = (p->bInvert ? p->apValue : &p->apValue[p->nCol]);
+
+    /* If this is an UPDATE or DELETE, read the old.* record. */
+    if( p->op!=SQLITE_INSERT && (p->bPatchset==0 || p->op==SQLITE_DELETE) ){
+      u8 *abPK = p->bPatchset ? p->abPK : 0;
+      p->rc = sessionReadRecord(&p->in, p->nCol, abPK, apOld, 0);
+      if( p->rc!=SQLITE_OK ) return p->rc;
+    }
+
+    /* If this is an INSERT or UPDATE, read the new.* record. */
+    if( p->op!=SQLITE_DELETE ){
+      p->rc = sessionReadRecord(&p->in, p->nCol, 0, apNew, pbEmpty);
+      if( p->rc!=SQLITE_OK ) return p->rc;
+    }
+
+    if( (p->bPatchset || p->bInvert) && p->op==SQLITE_UPDATE ){
+      /* If this is an UPDATE that is part of a patchset, then all PK and
+      ** modified fields are present in the new.* record. The old.* record
+      ** is currently completely empty. This block shifts the PK fields from
+      ** new.* to old.*, to accommodate the code that reads these arrays.  */
+      for(i=0; i<p->nCol; i++){
+        assert( p->bPatchset==0 || p->apValue[i]==0 );
+        if( p->abPK[i] ){
+          assert( p->apValue[i]==0 );
+          p->apValue[i] = p->apValue[i+p->nCol];
+          if( p->apValue[i]==0 ) return (p->rc = SQLITE_CORRUPT_BKPT);
+          p->apValue[i+p->nCol] = 0;
+        }
+      }
+    }else if( p->bInvert ){
+      if( p->op==SQLITE_INSERT ) p->op = SQLITE_DELETE;
+      else if( p->op==SQLITE_DELETE ) p->op = SQLITE_INSERT;
+    }
+
+    /* If this is an UPDATE that is part of a changeset, then check that
+    ** there are no fields in the old.* record that are not (a) PK fields,
+    ** or (b) also present in the new.* record.
+    **
+    ** Such records are technically corrupt, but the rebaser was at one
+    ** point generating them. Under most circumstances this is benign, but
+    ** can cause spurious SQLITE_RANGE errors when applying the changeset. */
+    if( p->bPatchset==0 && p->op==SQLITE_UPDATE){
+      for(i=0; i<p->nCol; i++){
+        if( p->abPK[i]==0 && p->apValue[i+p->nCol]==0 ){
+          sqlite3ValueFree(p->apValue[i]);
+          p->apValue[i] = 0;
+        }
+      }
+    }
+  }
+
+  return SQLITE_ROW;
+}
+
+/*
+** Advance the changeset iterator to the next change.
+**
+** If both paRec and pnRec are NULL, then this function works like the public
+** API sqlite3changeset_next(). If SQLITE_ROW is returned, then the
+** sqlite3changeset_new() and old() APIs may be used to query for values.
+**
+** Otherwise, if paRec and pnRec are not NULL, then a pointer to the change
+** record is written to *paRec before returning and the number of bytes in
+** the record to *pnRec.
+**
+** Either way, this function returns SQLITE_ROW if the iterator is
+** successfully advanced to the next change in the changeset, an SQLite
+** error code if an error occurs, or SQLITE_DONE if there are no further
+** changes in the changeset.
+*/
+static int sessionChangesetNext(
+  sqlite3_changeset_iter *p,      /* Changeset iterator */
+  u8 **paRec,                     /* If non-NULL, store record pointer here */
+  int *pnRec,                     /* If non-NULL, store size of record here */
+  int *pbNew                      /* If non-NULL, true if new table */
+){
+  int bEmpty;
+  int rc;
+  do {
+    bEmpty = 0;
+    rc = sessionChangesetNextOne(p, paRec, pnRec, pbNew, &bEmpty);
+  }while( rc==SQLITE_ROW && p->bSkipEmpty && bEmpty);
+  return rc;
+}
+
+/*
+** Advance an iterator created by sqlite3changeset_start() to the next
+** change in the changeset. This function may return SQLITE_ROW, SQLITE_DONE
+** or SQLITE_CORRUPT.
+**
+** This function may not be called on iterators passed to a conflict handler
+** callback by changeset_apply().
+*/
+SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *p){
+  return sessionChangesetNext(p, 0, 0, 0);
+}
+
+/*
+** The following function extracts information on the current change
+** from a changeset iterator. It may only be called after changeset_next()
+** has returned SQLITE_ROW.
+*/
+SQLITE_API int sqlite3changeset_op(
+  sqlite3_changeset_iter *pIter,  /* Iterator handle */
+  const char **pzTab,             /* OUT: Pointer to table name */
+  int *pnCol,                     /* OUT: Number of columns in table */
+  int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
+  int *pbIndirect                 /* OUT: True if change is indirect */
+){
+  *pOp = pIter->op;
+  *pnCol = pIter->nCol;
+  *pzTab = pIter->zTab;
+  if( pbIndirect ) *pbIndirect = pIter->bIndirect;
+  return SQLITE_OK;
+}
+
+/*
+** Return information regarding the PRIMARY KEY and number of columns in
+** the database table affected by the change that pIter currently points
+** to. This function may only be called after changeset_next() returns
+** SQLITE_ROW.
+*/
+SQLITE_API int sqlite3changeset_pk(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
+  int *pnCol                      /* OUT: Number of entries in output array */
+){
+  *pabPK = pIter->abPK;
+  if( pnCol ) *pnCol = pIter->nCol;
+  return SQLITE_OK;
+}
+
+/*
+** This function may only be called while the iterator is pointing to an
+** SQLITE_UPDATE or SQLITE_DELETE change (see sqlite3changeset_op()).
+** Otherwise, SQLITE_MISUSE is returned.
+**
+** It sets *ppValue to point to an sqlite3_value structure containing the
+** iVal'th value in the old.* record. Or, if that particular value is not
+** included in the record (because the change is an UPDATE and the field
+** was not modified and is not a PK column), set *ppValue to NULL.
+**
+** If value iVal is out-of-range, SQLITE_RANGE is returned and *ppValue is
+** not modified. Otherwise, SQLITE_OK.
+*/
+SQLITE_API int sqlite3changeset_old(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Index of old.* value to retrieve */
+  sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
+){
+  if( pIter->op!=SQLITE_UPDATE && pIter->op!=SQLITE_DELETE ){
+    return SQLITE_MISUSE;
+  }
+  if( iVal<0 || iVal>=pIter->nCol ){
+    return SQLITE_RANGE;
+  }
+  *ppValue = pIter->apValue[iVal];
+  return SQLITE_OK;
+}
+
+/*
+** This function may only be called while the iterator is pointing to an
+** SQLITE_UPDATE or SQLITE_INSERT change (see sqlite3changeset_op()).
+** Otherwise, SQLITE_MISUSE is returned.
+**
+** It sets *ppValue to point to an sqlite3_value structure containing the
+** iVal'th value in the new.* record. Or, if that particular value is not
+** included in the record (because the change is an UPDATE and the field
+** was not modified), set *ppValue to NULL.
+**
+** If value iVal is out-of-range, SQLITE_RANGE is returned and *ppValue is
+** not modified. Otherwise, SQLITE_OK.
+*/
+SQLITE_API int sqlite3changeset_new(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Index of new.* value to retrieve */
+  sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
+){
+  if( pIter->op!=SQLITE_UPDATE && pIter->op!=SQLITE_INSERT ){
+    return SQLITE_MISUSE;
+  }
+  if( iVal<0 || iVal>=pIter->nCol ){
+    return SQLITE_RANGE;
+  }
+  *ppValue = pIter->apValue[pIter->nCol+iVal];
+  return SQLITE_OK;
+}
+
+/*
+** The following two macros are used internally. They are similar to the
+** sqlite3changeset_new() and sqlite3changeset_old() functions, except that
+** they omit all error checking and return a pointer to the requested value.
+*/
+#define sessionChangesetNew(pIter, iVal) (pIter)->apValue[(pIter)->nCol+(iVal)]
+#define sessionChangesetOld(pIter, iVal) (pIter)->apValue[(iVal)]
+
+/*
+** This function may only be called with a changeset iterator that has been
+** passed to an SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT
+** conflict-handler function. Otherwise, SQLITE_MISUSE is returned.
+**
+** If successful, *ppValue is set to point to an sqlite3_value structure
+** containing the iVal'th value of the conflicting record.
+**
+** If value iVal is out-of-range or some other error occurs, an SQLite error
+** code is returned. Otherwise, SQLITE_OK.
+*/
+SQLITE_API int sqlite3changeset_conflict(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Index of conflict record value to fetch */
+  sqlite3_value **ppValue         /* OUT: Value from conflicting row */
+){
+  if( !pIter->pConflict ){
+    return SQLITE_MISUSE;
+  }
+  if( iVal<0 || iVal>=pIter->nCol ){
+    return SQLITE_RANGE;
+  }
+  *ppValue = sqlite3_column_value(pIter->pConflict, iVal);
+  return SQLITE_OK;
+}
+
+/*
+** This function may only be called with an iterator passed to an
+** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
+** it sets the output variable to the total number of known foreign key
+** violations in the destination database and returns SQLITE_OK.
+**
+** In all other cases this function returns SQLITE_MISUSE.
+*/
+SQLITE_API int sqlite3changeset_fk_conflicts(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int *pnOut                      /* OUT: Number of FK violations */
+){
+  if( pIter->pConflict || pIter->apValue ){
+    return SQLITE_MISUSE;
+  }
+  *pnOut = pIter->nCol;
+  return SQLITE_OK;
+}
+
+
+/*
+** Finalize an iterator allocated with sqlite3changeset_start().
+**
+** This function may not be called on iterators passed to a conflict handler
+** callback by changeset_apply().
+*/
+SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *p){
+  int rc = SQLITE_OK;
+  if( p ){
+    int i;                        /* Used to iterate through p->apValue[] */
+    rc = p->rc;
+    if( p->apValue ){
+      for(i=0; i<p->nCol*2; i++) sqlite3ValueFree(p->apValue[i]);
+    }
+    sqlite3_free(p->tblhdr.aBuf);
+    sqlite3_free(p->in.buf.aBuf);
+    sqlite3_free(p);
+  }
+  return rc;
+}
+
+static int sessionChangesetInvert(
+  SessionInput *pInput,           /* Input changeset */
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut,
+  int *pnInverted,                /* OUT: Number of bytes in output changeset */
+  void **ppInverted               /* OUT: Inverse of pChangeset */
+){
+  int rc = SQLITE_OK;             /* Return value */
+  SessionBuffer sOut;             /* Output buffer */
+  int nCol = 0;                   /* Number of cols in current table */
+  u8 *abPK = 0;                   /* PK array for current table */
+  sqlite3_value **apVal = 0;      /* Space for values for UPDATE inversion */
+  SessionBuffer sPK = {0, 0, 0};  /* PK array for current table */
+
+  /* Initialize the output buffer */
+  memset(&sOut, 0, sizeof(SessionBuffer));
+
+  /* Zero the output variables in case an error occurs. */
+  if( ppInverted ){
+    *ppInverted = 0;
+    *pnInverted = 0;
+  }
+
+  while( 1 ){
+    u8 eType;
+
+    /* Test for EOF. */
+    if( (rc = sessionInputBuffer(pInput, 2)) ) goto finished_invert;
+    if( pInput->iNext>=pInput->nData ) break;
+    eType = pInput->aData[pInput->iNext];
+
+    switch( eType ){
+      case 'T': {
+        /* A 'table' record consists of:
+        **
+        **   * A constant 'T' character,
+        **   * Number of columns in said table (a varint),
+        **   * An array of nCol bytes (sPK),
+        **   * A nul-terminated table name.
+        */
+        int nByte;
+        int nVar;
+        pInput->iNext++;
+        if( (rc = sessionChangesetBufferTblhdr(pInput, &nByte)) ){
+          goto finished_invert;
+        }
+        nVar = sessionVarintGet(&pInput->aData[pInput->iNext], &nCol);
+        sPK.nBuf = 0;
+        sessionAppendBlob(&sPK, &pInput->aData[pInput->iNext+nVar], nCol, &rc);
+        sessionAppendByte(&sOut, eType, &rc);
+        sessionAppendBlob(&sOut, &pInput->aData[pInput->iNext], nByte, &rc);
+        if( rc ) goto finished_invert;
+
+        pInput->iNext += nByte;
+        sqlite3_free(apVal);
+        apVal = 0;
+        abPK = sPK.aBuf;
+        break;
+      }
+
+      case SQLITE_INSERT:
+      case SQLITE_DELETE: {
+        int nByte;
+        int bIndirect = pInput->aData[pInput->iNext+1];
+        int eType2 = (eType==SQLITE_DELETE ? SQLITE_INSERT : SQLITE_DELETE);
+        pInput->iNext += 2;
+        assert( rc==SQLITE_OK );
+        rc = sessionChangesetBufferRecord(pInput, nCol, &nByte);
+        sessionAppendByte(&sOut, eType2, &rc);
+        sessionAppendByte(&sOut, bIndirect, &rc);
+        sessionAppendBlob(&sOut, &pInput->aData[pInput->iNext], nByte, &rc);
+        pInput->iNext += nByte;
+        if( rc ) goto finished_invert;
+        break;
+      }
+
+      case SQLITE_UPDATE: {
+        int iCol;
+
+        if( 0==apVal ){
+          apVal = (sqlite3_value **)sqlite3_malloc64(sizeof(apVal[0])*nCol*2);
+          if( 0==apVal ){
+            rc = SQLITE_NOMEM;
+            goto finished_invert;
+          }
+          memset(apVal, 0, sizeof(apVal[0])*nCol*2);
+        }
+
+        /* Write the header for the new UPDATE change. Same as the original. */
+        sessionAppendByte(&sOut, eType, &rc);
+        sessionAppendByte(&sOut, pInput->aData[pInput->iNext+1], &rc);
+
+        /* Read the old.* and new.* records for the update change. */
+        pInput->iNext += 2;
+        rc = sessionReadRecord(pInput, nCol, 0, &apVal[0], 0);
+        if( rc==SQLITE_OK ){
+          rc = sessionReadRecord(pInput, nCol, 0, &apVal[nCol], 0);
+        }
+
+        /* Write the new old.* record. Consists of the PK columns from the
+        ** original old.* record, and the other values from the original
+        ** new.* record. */
+        for(iCol=0; iCol<nCol; iCol++){
+          sqlite3_value *pVal = apVal[iCol + (abPK[iCol] ? 0 : nCol)];
+          sessionAppendValue(&sOut, pVal, &rc);
+        }
+
+        /* Write the new new.* record. Consists of a copy of all values
+        ** from the original old.* record, except for the PK columns, which
+        ** are set to "undefined". */
+        for(iCol=0; iCol<nCol; iCol++){
+          sqlite3_value *pVal = (abPK[iCol] ? 0 : apVal[iCol]);
+          sessionAppendValue(&sOut, pVal, &rc);
+        }
+
+        for(iCol=0; iCol<nCol*2; iCol++){
+          sqlite3ValueFree(apVal[iCol]);
+        }
+        memset(apVal, 0, sizeof(apVal[0])*nCol*2);
+        if( rc!=SQLITE_OK ){
+          goto finished_invert;
+        }
+
+        break;
+      }
+
+      default:
+        rc = SQLITE_CORRUPT_BKPT;
+        goto finished_invert;
+    }
+
+    assert( rc==SQLITE_OK );
+    if( xOutput && sOut.nBuf>=sessions_strm_chunk_size ){
+      rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
+      sOut.nBuf = 0;
+      if( rc!=SQLITE_OK ) goto finished_invert;
+    }
+  }
+
+  assert( rc==SQLITE_OK );
+  if( pnInverted && ALWAYS(ppInverted) ){
+    *pnInverted = sOut.nBuf;
+    *ppInverted = sOut.aBuf;
+    sOut.aBuf = 0;
+  }else if( sOut.nBuf>0 && ALWAYS(xOutput!=0) ){
+    rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
+  }
+
+ finished_invert:
+  sqlite3_free(sOut.aBuf);
+  sqlite3_free(apVal);
+  sqlite3_free(sPK.aBuf);
+  return rc;
+}
+
+
+/*
+** Invert a changeset object.
+*/
+SQLITE_API int sqlite3changeset_invert(
+  int nChangeset,                 /* Number of bytes in input */
+  const void *pChangeset,         /* Input changeset */
+  int *pnInverted,                /* OUT: Number of bytes in output changeset */
+  void **ppInverted               /* OUT: Inverse of pChangeset */
+){
+  SessionInput sInput;
+
+  /* Set up the input stream */
+  memset(&sInput, 0, sizeof(SessionInput));
+  sInput.nData = nChangeset;
+  sInput.aData = (u8*)pChangeset;
+
+  return sessionChangesetInvert(&sInput, 0, 0, pnInverted, ppInverted);
+}
+
+/*
+** Streaming version of sqlite3changeset_invert().
+*/
+SQLITE_API int sqlite3changeset_invert_strm(
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  SessionInput sInput;
+  int rc;
+
+  /* Set up the input stream */
+  memset(&sInput, 0, sizeof(SessionInput));
+  sInput.xInput = xInput;
+  sInput.pIn = pIn;
+
+  rc = sessionChangesetInvert(&sInput, xOutput, pOut, 0, 0);
+  sqlite3_free(sInput.buf.aBuf);
+  return rc;
+}
+
+
+typedef struct SessionUpdate SessionUpdate;
+struct SessionUpdate {
+  sqlite3_stmt *pStmt;
+  u32 *aMask;
+  SessionUpdate *pNext;
+};
+
+typedef struct SessionApplyCtx SessionApplyCtx;
+struct SessionApplyCtx {
+  sqlite3 *db;
+  sqlite3_stmt *pDelete;          /* DELETE statement */
+  sqlite3_stmt *pInsert;          /* INSERT statement */
+  sqlite3_stmt *pSelect;          /* SELECT statement */
+  int nCol;                       /* Size of azCol[] and abPK[] arrays */
+  const char **azCol;             /* Array of column names */
+  u8 *abPK;                       /* Boolean array - true if column is in PK */
+  u32 *aUpdateMask;               /* Used by sessionUpdateFind */
+  SessionUpdate *pUp;
+  int bStat1;                     /* True if table is sqlite_stat1 */
+  int bDeferConstraints;          /* True to defer constraints */
+  int bInvertConstraints;         /* Invert when iterating constraints buffer */
+  SessionBuffer constraints;      /* Deferred constraints are stored here */
+  SessionBuffer rebase;           /* Rebase information (if any) here */
+  u8 bRebaseStarted;              /* If table header is already in rebase */
+  u8 bRebase;                     /* True to collect rebase information */
+  u8 bIgnoreNoop;                 /* True to ignore no-op conflicts */
+  int bRowid;
+};
+
+/* Number of prepared UPDATE statements to cache. */
+#define SESSION_UPDATE_CACHE_SZ 12
+
+/*
+** Find a prepared UPDATE statement suitable for the UPDATE step currently
+** being visited by the iterator. The UPDATE is of the form:
+**
+**   UPDATE tbl SET col = ?, col2 = ? WHERE pk1 IS ? AND pk2 IS ?
+*/
+static int sessionUpdateFind(
+  sqlite3_changeset_iter *pIter,
+  SessionApplyCtx *p,
+  int bPatchset,
+  sqlite3_stmt **ppStmt
+){
+  int rc = SQLITE_OK;
+  SessionUpdate *pUp = 0;
+  int nCol = pIter->nCol;
+  int nU32 = (pIter->nCol+33)/32;
+  int ii;
+
+  if( p->aUpdateMask==0 ){
+    p->aUpdateMask = sqlite3_malloc(nU32*sizeof(u32));
+    if( p->aUpdateMask==0 ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    memset(p->aUpdateMask, 0, nU32*sizeof(u32));
+    rc = SQLITE_CORRUPT;
+    for(ii=0; ii<pIter->nCol; ii++){
+      if( sessionChangesetNew(pIter, ii) ){
+        p->aUpdateMask[ii/32] |= (1<<(ii%32));
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( bPatchset ) p->aUpdateMask[nCol/32] |= (1<<(nCol%32));
+
+    if( p->pUp ){
+      int nUp = 0;
+      SessionUpdate **pp = &p->pUp;
+      while( 1 ){
+        nUp++;
+        if( 0==memcmp(p->aUpdateMask, (*pp)->aMask, nU32*sizeof(u32)) ){
+          pUp = *pp;
+          *pp = pUp->pNext;
+          pUp->pNext = p->pUp;
+          p->pUp = pUp;
+          break;
+        }
+
+        if( (*pp)->pNext ){
+          pp = &(*pp)->pNext;
+        }else{
+          if( nUp>=SESSION_UPDATE_CACHE_SZ ){
+            sqlite3_finalize((*pp)->pStmt);
+            sqlite3_free(*pp);
+            *pp = 0;
+          }
+          break;
+        }
+      }
+    }
+
+    if( pUp==0 ){
+      int nByte = sizeof(SessionUpdate) * nU32*sizeof(u32);
+      int bStat1 = (sqlite3_stricmp(pIter->zTab, "sqlite_stat1")==0);
+      pUp = (SessionUpdate*)sqlite3_malloc(nByte);
+      if( pUp==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        const char *zSep = "";
+        SessionBuffer buf;
+
+        memset(&buf, 0, sizeof(buf));
+        pUp->aMask = (u32*)&pUp[1];
+        memcpy(pUp->aMask, p->aUpdateMask, nU32*sizeof(u32));
+
+        sessionAppendStr(&buf, "UPDATE main.", &rc);
+        sessionAppendIdent(&buf, pIter->zTab, &rc);
+        sessionAppendStr(&buf, " SET ", &rc);
+
+        /* Create the assignments part of the UPDATE */
+        for(ii=0; ii<pIter->nCol; ii++){
+          if( p->abPK[ii]==0 && sessionChangesetNew(pIter, ii) ){
+            sessionAppendStr(&buf, zSep, &rc);
+            sessionAppendIdent(&buf, p->azCol[ii], &rc);
+            sessionAppendStr(&buf, " = ?", &rc);
+            sessionAppendInteger(&buf, ii*2+1, &rc);
+            zSep = ", ";
+          }
+        }
+
+        /* Create the WHERE clause part of the UPDATE */
+        zSep = "";
+        sessionAppendStr(&buf, " WHERE ", &rc);
+        for(ii=0; ii<pIter->nCol; ii++){
+          if( p->abPK[ii] || (bPatchset==0 && sessionChangesetOld(pIter, ii)) ){
+            sessionAppendStr(&buf, zSep, &rc);
+            if( bStat1 && ii==1 ){
+              assert( sqlite3_stricmp(p->azCol[ii], "idx")==0 );
+              sessionAppendStr(&buf,
+                  "idx IS CASE "
+                  "WHEN length(?4)=0 AND typeof(?4)='blob' THEN NULL "
+                  "ELSE ?4 END ", &rc
+              );
+            }else{
+              sessionAppendIdent(&buf, p->azCol[ii], &rc);
+              sessionAppendStr(&buf, " IS ?", &rc);
+              sessionAppendInteger(&buf, ii*2+2, &rc);
+            }
+            zSep = " AND ";
+          }
+        }
+
+        if( rc==SQLITE_OK ){
+          char *zSql = (char*)buf.aBuf;
+          rc = sqlite3_prepare_v2(p->db, zSql, buf.nBuf, &pUp->pStmt, 0);
+        }
+
+        if( rc!=SQLITE_OK ){
+          sqlite3_free(pUp);
+          pUp = 0;
+        }else{
+          pUp->pNext = p->pUp;
+          p->pUp = pUp;
+        }
+        sqlite3_free(buf.aBuf);
+      }
+    }
+  }
+
+  assert( (rc==SQLITE_OK)==(pUp!=0) );
+  if( pUp ){
+    *ppStmt = pUp->pStmt;
+  }else{
+    *ppStmt = 0;
+  }
+  return rc;
+}
+
+/*
+** Free all cached UPDATE statements.
+*/
+static void sessionUpdateFree(SessionApplyCtx *p){
+  SessionUpdate *pUp;
+  SessionUpdate *pNext;
+  for(pUp=p->pUp; pUp; pUp=pNext){
+    pNext = pUp->pNext;
+    sqlite3_finalize(pUp->pStmt);
+    sqlite3_free(pUp);
+  }
+  p->pUp = 0;
+  sqlite3_free(p->aUpdateMask);
+  p->aUpdateMask = 0;
+}
+
+/*
+** Formulate a statement to DELETE a row from database db. Assuming a table
+** structure like this:
+**
+**     CREATE TABLE x(a, b, c, d, PRIMARY KEY(a, c));
+**
+** The DELETE statement looks like this:
+**
+**     DELETE FROM x WHERE a = :1 AND c = :3 AND (:5 OR b IS :2 AND d IS :4)
+**
+** Variable :5 (nCol+1) is a boolean. It should be set to 0 if we require
+** matching b and d values, or 1 otherwise. The second case comes up if the
+** conflict handler is invoked with NOTFOUND and returns CHANGESET_REPLACE.
+**
+** If successful, SQLITE_OK is returned and SessionApplyCtx.pDelete is left
+** pointing to the prepared version of the SQL statement.
+*/
+static int sessionDeleteRow(
+  sqlite3 *db,                    /* Database handle */
+  const char *zTab,               /* Table name */
+  SessionApplyCtx *p              /* Session changeset-apply context */
+){
+  int i;
+  const char *zSep = "";
+  int rc = SQLITE_OK;
+  SessionBuffer buf = {0, 0, 0};
+  int nPk = 0;
+
+  sessionAppendStr(&buf, "DELETE FROM main.", &rc);
+  sessionAppendIdent(&buf, zTab, &rc);
+  sessionAppendStr(&buf, " WHERE ", &rc);
+
+  for(i=0; i<p->nCol; i++){
+    if( p->abPK[i] ){
+      nPk++;
+      sessionAppendStr(&buf, zSep, &rc);
+      sessionAppendIdent(&buf, p->azCol[i], &rc);
+      sessionAppendStr(&buf, " = ?", &rc);
+      sessionAppendInteger(&buf, i+1, &rc);
+      zSep = " AND ";
+    }
+  }
+
+  if( nPk<p->nCol ){
+    sessionAppendStr(&buf, " AND (?", &rc);
+    sessionAppendInteger(&buf, p->nCol+1, &rc);
+    sessionAppendStr(&buf, " OR ", &rc);
+
+    zSep = "";
+    for(i=0; i<p->nCol; i++){
+      if( !p->abPK[i] ){
+        sessionAppendStr(&buf, zSep, &rc);
+        sessionAppendIdent(&buf, p->azCol[i], &rc);
+        sessionAppendStr(&buf, " IS ?", &rc);
+        sessionAppendInteger(&buf, i+1, &rc);
+        zSep = "AND ";
+      }
+    }
+    sessionAppendStr(&buf, ")", &rc);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_prepare_v2(db, (char *)buf.aBuf, buf.nBuf, &p->pDelete, 0);
+  }
+  sqlite3_free(buf.aBuf);
+
+  return rc;
+}
+
+/*
+** Formulate and prepare an SQL statement to query table zTab by primary
+** key. Assuming the following table structure:
+**
+**     CREATE TABLE x(a, b, c, d, PRIMARY KEY(a, c));
+**
+** The SELECT statement looks like this:
+**
+**     SELECT * FROM x WHERE a = ?1 AND c = ?3
+**
+** If successful, SQLITE_OK is returned and SessionApplyCtx.pSelect is left
+** pointing to the prepared version of the SQL statement.
+*/
+static int sessionSelectRow(
+  sqlite3 *db,                    /* Database handle */
+  const char *zTab,               /* Table name */
+  SessionApplyCtx *p              /* Session changeset-apply context */
+){
+  /* TODO */
+  return sessionSelectStmt(db, p->bIgnoreNoop,
+      "main", zTab, p->bRowid, p->nCol, p->azCol, p->abPK, &p->pSelect
+  );
+}
+
+/*
+** Formulate and prepare an INSERT statement to add a record to table zTab.
+** For example:
+**
+**     INSERT INTO main."zTab" VALUES(?1, ?2, ?3 ...);
+**
+** If successful, SQLITE_OK is returned and SessionApplyCtx.pInsert is left
+** pointing to the prepared version of the SQL statement.
+*/
+static int sessionInsertRow(
+  sqlite3 *db,                    /* Database handle */
+  const char *zTab,               /* Table name */
+  SessionApplyCtx *p              /* Session changeset-apply context */
+){
+  int rc = SQLITE_OK;
+  int i;
+  SessionBuffer buf = {0, 0, 0};
+
+  sessionAppendStr(&buf, "INSERT INTO main.", &rc);
+  sessionAppendIdent(&buf, zTab, &rc);
+  sessionAppendStr(&buf, "(", &rc);
+  for(i=0; i<p->nCol; i++){
+    if( i!=0 ) sessionAppendStr(&buf, ", ", &rc);
+    sessionAppendIdent(&buf, p->azCol[i], &rc);
+  }
+
+  sessionAppendStr(&buf, ") VALUES(?", &rc);
+  for(i=1; i<p->nCol; i++){
+    sessionAppendStr(&buf, ", ?", &rc);
+  }
+  sessionAppendStr(&buf, ")", &rc);
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_prepare_v2(db, (char *)buf.aBuf, buf.nBuf, &p->pInsert, 0);
+  }
+  sqlite3_free(buf.aBuf);
+  return rc;
+}
+
+static int sessionPrepare(sqlite3 *db, sqlite3_stmt **pp, const char *zSql){
+  return sqlite3_prepare_v2(db, zSql, -1, pp, 0);
+}
+
+/*
+** Prepare statements for applying changes to the sqlite_stat1 table.
+** These are similar to those created by sessionSelectRow(),
+** sessionInsertRow(), sessionUpdateRow() and sessionDeleteRow() for
+** other tables.
+*/
+static int sessionStat1Sql(sqlite3 *db, SessionApplyCtx *p){
+  int rc = sessionSelectRow(db, "sqlite_stat1", p);
+  if( rc==SQLITE_OK ){
+    rc = sessionPrepare(db, &p->pInsert,
+        "INSERT INTO main.sqlite_stat1 VALUES(?1, "
+        "CASE WHEN length(?2)=0 AND typeof(?2)='blob' THEN NULL ELSE ?2 END, "
+        "?3)"
+    );
+  }
+  if( rc==SQLITE_OK ){
+    rc = sessionPrepare(db, &p->pDelete,
+        "DELETE FROM main.sqlite_stat1 WHERE tbl=?1 AND idx IS "
+        "CASE WHEN length(?2)=0 AND typeof(?2)='blob' THEN NULL ELSE ?2 END "
+        "AND (?4 OR stat IS ?3)"
+    );
+  }
+  return rc;
+}
+
+/*
+** A wrapper around sqlite3_bind_value() that detects an extra problem.
+** See comments in the body of this function for details.
+*/
+static int sessionBindValue(
+  sqlite3_stmt *pStmt,            /* Statement to bind value to */
+  int i,                          /* Parameter number to bind to */
+  sqlite3_value *pVal             /* Value to bind */
+){
+  int eType = sqlite3_value_type(pVal);
+  /* COVERAGE: The (pVal->z==0) branch is never true using current versions
+  ** of SQLite. If a malloc fails in an sqlite3_value_xxx() function, either
+  ** the (pVal->z) variable remains as it was or the type of the value is
+  ** set to SQLITE_NULL.  */
+  if( (eType==SQLITE_TEXT || eType==SQLITE_BLOB) && pVal->z==0 ){
+    /* This condition occurs when an earlier OOM in a call to
+    ** sqlite3_value_text() or sqlite3_value_blob() (perhaps from within
+    ** a conflict-handler) has zeroed the pVal->z pointer. Return NOMEM. */
+    return SQLITE_NOMEM;
+  }
+  return sqlite3_bind_value(pStmt, i, pVal);
+}
+
+/*
+** Iterator pIter must point to an SQLITE_INSERT entry. This function
+** transfers new.* values from the current iterator entry to statement
+** pStmt. The table being inserted into has nCol columns.
+**
+** New.* value $i from the iterator is bound to variable ($i+1) of
+** statement pStmt. If parameter abPK is NULL, all values from 0 to (nCol-1)
+** are transfered to the statement. Otherwise, if abPK is not NULL, it points
+** to an array nCol elements in size. In this case only those values for
+** which abPK[$i] is true are read from the iterator and bound to the
+** statement.
+**
+** An SQLite error code is returned if an error occurs. Otherwise, SQLITE_OK.
+*/
+static int sessionBindRow(
+  sqlite3_changeset_iter *pIter,  /* Iterator to read values from */
+  int(*xValue)(sqlite3_changeset_iter *, int, sqlite3_value **),
+  int nCol,                       /* Number of columns */
+  u8 *abPK,                       /* If not NULL, bind only if true */
+  sqlite3_stmt *pStmt             /* Bind values to this statement */
+){
+  int i;
+  int rc = SQLITE_OK;
+
+  /* Neither sqlite3changeset_old or sqlite3changeset_new can fail if the
+  ** argument iterator points to a suitable entry. Make sure that xValue
+  ** is one of these to guarantee that it is safe to ignore the return
+  ** in the code below. */
+  assert( xValue==sqlite3changeset_old || xValue==sqlite3changeset_new );
+
+  for(i=0; rc==SQLITE_OK && i<nCol; i++){
+    if( !abPK || abPK[i] ){
+      sqlite3_value *pVal = 0;
+      (void)xValue(pIter, i, &pVal);
+      if( pVal==0 ){
+        /* The value in the changeset was "undefined". This indicates a
+        ** corrupt changeset blob.  */
+        rc = SQLITE_CORRUPT_BKPT;
+      }else{
+        rc = sessionBindValue(pStmt, i+1, pVal);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** SQL statement pSelect is as generated by the sessionSelectRow() function.
+** This function binds the primary key values from the change that changeset
+** iterator pIter points to to the SELECT and attempts to seek to the table
+** entry. If a row is found, the SELECT statement left pointing at the row
+** and SQLITE_ROW is returned. Otherwise, if no row is found and no error
+** has occured, the statement is reset and SQLITE_OK is returned. If an
+** error occurs, the statement is reset and an SQLite error code is returned.
+**
+** If this function returns SQLITE_ROW, the caller must eventually reset()
+** statement pSelect. If any other value is returned, the statement does
+** not require a reset().
+**
+** If the iterator currently points to an INSERT record, bind values from the
+** new.* record to the SELECT statement. Or, if it points to a DELETE or
+** UPDATE, bind values from the old.* record.
+*/
+static int sessionSeekToRow(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  SessionApplyCtx *p
+){
+  sqlite3_stmt *pSelect = p->pSelect;
+  int rc;                         /* Return code */
+  int nCol;                       /* Number of columns in table */
+  int op;                         /* Changset operation (SQLITE_UPDATE etc.) */
+  const char *zDummy;             /* Unused */
+
+  sqlite3_clear_bindings(pSelect);
+  sqlite3changeset_op(pIter, &zDummy, &nCol, &op, 0);
+  rc = sessionBindRow(pIter,
+      op==SQLITE_INSERT ? sqlite3changeset_new : sqlite3changeset_old,
+      nCol, p->abPK, pSelect
+  );
+
+  if( op!=SQLITE_DELETE && p->bIgnoreNoop ){
+    int ii;
+    for(ii=0; rc==SQLITE_OK && ii<nCol; ii++){
+      if( p->abPK[ii]==0 ){
+        sqlite3_value *pVal = 0;
+        sqlite3changeset_new(pIter, ii, &pVal);
+        sqlite3_bind_int(pSelect, ii+1+nCol, (pVal==0));
+        if( pVal ) rc = sessionBindValue(pSelect, ii+1, pVal);
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_step(pSelect);
+    if( rc!=SQLITE_ROW ) rc = sqlite3_reset(pSelect);
+  }
+
+  return rc;
+}
+
+/*
+** This function is called from within sqlite3changeset_apply_v2() when
+** a conflict is encountered and resolved using conflict resolution
+** mode eType (either SQLITE_CHANGESET_OMIT or SQLITE_CHANGESET_REPLACE)..
+** It adds a conflict resolution record to the buffer in
+** SessionApplyCtx.rebase, which will eventually be returned to the caller
+** of apply_v2() as the "rebase" buffer.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise.
+*/
+static int sessionRebaseAdd(
+  SessionApplyCtx *p,             /* Apply context */
+  int eType,                      /* Conflict resolution (OMIT or REPLACE) */
+  sqlite3_changeset_iter *pIter   /* Iterator pointing at current change */
+){
+  int rc = SQLITE_OK;
+  if( p->bRebase ){
+    int i;
+    int eOp = pIter->op;
+    if( p->bRebaseStarted==0 ){
+      /* Append a table-header to the rebase buffer */
+      const char *zTab = pIter->zTab;
+      sessionAppendByte(&p->rebase, 'T', &rc);
+      sessionAppendVarint(&p->rebase, p->nCol, &rc);
+      sessionAppendBlob(&p->rebase, p->abPK, p->nCol, &rc);
+      sessionAppendBlob(&p->rebase, (u8*)zTab, (int)strlen(zTab)+1, &rc);
+      p->bRebaseStarted = 1;
+    }
+
+    assert( eType==SQLITE_CHANGESET_REPLACE||eType==SQLITE_CHANGESET_OMIT );
+    assert( eOp==SQLITE_DELETE || eOp==SQLITE_INSERT || eOp==SQLITE_UPDATE );
+
+    sessionAppendByte(&p->rebase,
+        (eOp==SQLITE_DELETE ? SQLITE_DELETE : SQLITE_INSERT), &rc
+        );
+    sessionAppendByte(&p->rebase, (eType==SQLITE_CHANGESET_REPLACE), &rc);
+    for(i=0; i<p->nCol; i++){
+      sqlite3_value *pVal = 0;
+      if( eOp==SQLITE_DELETE || (eOp==SQLITE_UPDATE && p->abPK[i]) ){
+        sqlite3changeset_old(pIter, i, &pVal);
+      }else{
+        sqlite3changeset_new(pIter, i, &pVal);
+      }
+      sessionAppendValue(&p->rebase, pVal, &rc);
+    }
+  }
+  return rc;
+}
+
+/*
+** Invoke the conflict handler for the change that the changeset iterator
+** currently points to.
+**
+** Argument eType must be either CHANGESET_DATA or CHANGESET_CONFLICT.
+** If argument pbReplace is NULL, then the type of conflict handler invoked
+** depends solely on eType, as follows:
+**
+**    eType value                 Value passed to xConflict
+**    -------------------------------------------------
+**    CHANGESET_DATA              CHANGESET_NOTFOUND
+**    CHANGESET_CONFLICT          CHANGESET_CONSTRAINT
+**
+** Or, if pbReplace is not NULL, then an attempt is made to find an existing
+** record with the same primary key as the record about to be deleted, updated
+** or inserted. If such a record can be found, it is available to the conflict
+** handler as the "conflicting" record. In this case the type of conflict
+** handler invoked is as follows:
+**
+**    eType value         PK Record found?   Value passed to xConflict
+**    ----------------------------------------------------------------
+**    CHANGESET_DATA      Yes                CHANGESET_DATA
+**    CHANGESET_DATA      No                 CHANGESET_NOTFOUND
+**    CHANGESET_CONFLICT  Yes                CHANGESET_CONFLICT
+**    CHANGESET_CONFLICT  No                 CHANGESET_CONSTRAINT
+**
+** If pbReplace is not NULL, and a record with a matching PK is found, and
+** the conflict handler function returns SQLITE_CHANGESET_REPLACE, *pbReplace
+** is set to non-zero before returning SQLITE_OK.
+**
+** If the conflict handler returns SQLITE_CHANGESET_ABORT, SQLITE_ABORT is
+** returned. Or, if the conflict handler returns an invalid value,
+** SQLITE_MISUSE. If the conflict handler returns SQLITE_CHANGESET_OMIT,
+** this function returns SQLITE_OK.
+*/
+static int sessionConflictHandler(
+  int eType,                      /* Either CHANGESET_DATA or CONFLICT */
+  SessionApplyCtx *p,             /* changeset_apply() context */
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int(*xConflict)(void *, int, sqlite3_changeset_iter*),
+  void *pCtx,                     /* First argument for conflict handler */
+  int *pbReplace                  /* OUT: Set to true if PK row is found */
+){
+  int res = 0;                    /* Value returned by conflict handler */
+  int rc;
+  int nCol;
+  int op;
+  const char *zDummy;
+
+  sqlite3changeset_op(pIter, &zDummy, &nCol, &op, 0);
+
+  assert( eType==SQLITE_CHANGESET_CONFLICT || eType==SQLITE_CHANGESET_DATA );
+  assert( SQLITE_CHANGESET_CONFLICT+1==SQLITE_CHANGESET_CONSTRAINT );
+  assert( SQLITE_CHANGESET_DATA+1==SQLITE_CHANGESET_NOTFOUND );
+
+  /* Bind the new.* PRIMARY KEY values to the SELECT statement. */
+  if( pbReplace ){
+    rc = sessionSeekToRow(pIter, p);
+  }else{
+    rc = SQLITE_OK;
+  }
+
+  if( rc==SQLITE_ROW ){
+    /* There exists another row with the new.* primary key. */
+    if( p->bIgnoreNoop
+     && sqlite3_column_int(p->pSelect, sqlite3_column_count(p->pSelect)-1)
+    ){
+      res = SQLITE_CHANGESET_OMIT;
+    }else{
+      pIter->pConflict = p->pSelect;
+      res = xConflict(pCtx, eType, pIter);
+      pIter->pConflict = 0;
+    }
+    rc = sqlite3_reset(p->pSelect);
+  }else if( rc==SQLITE_OK ){
+    if( p->bDeferConstraints && eType==SQLITE_CHANGESET_CONFLICT ){
+      /* Instead of invoking the conflict handler, append the change blob
+      ** to the SessionApplyCtx.constraints buffer. */
+      u8 *aBlob = &pIter->in.aData[pIter->in.iCurrent];
+      int nBlob = pIter->in.iNext - pIter->in.iCurrent;
+      sessionAppendBlob(&p->constraints, aBlob, nBlob, &rc);
+      return SQLITE_OK;
+    }else{
+      /* No other row with the new.* primary key. */
+      res = xConflict(pCtx, eType+1, pIter);
+      if( res==SQLITE_CHANGESET_REPLACE ) rc = SQLITE_MISUSE;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    switch( res ){
+      case SQLITE_CHANGESET_REPLACE:
+        assert( pbReplace );
+        *pbReplace = 1;
+        break;
+
+      case SQLITE_CHANGESET_OMIT:
+        break;
+
+      case SQLITE_CHANGESET_ABORT:
+        rc = SQLITE_ABORT;
+        break;
+
+      default:
+        rc = SQLITE_MISUSE;
+        break;
+    }
+    if( rc==SQLITE_OK ){
+      rc = sessionRebaseAdd(p, res, pIter);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Attempt to apply the change that the iterator passed as the first argument
+** currently points to to the database. If a conflict is encountered, invoke
+** the conflict handler callback.
+**
+** If argument pbRetry is NULL, then ignore any CHANGESET_DATA conflict. If
+** one is encountered, update or delete the row with the matching primary key
+** instead. Or, if pbRetry is not NULL and a CHANGESET_DATA conflict occurs,
+** invoke the conflict handler. If it returns CHANGESET_REPLACE, set *pbRetry
+** to true before returning. In this case the caller will invoke this function
+** again, this time with pbRetry set to NULL.
+**
+** If argument pbReplace is NULL and a CHANGESET_CONFLICT conflict is
+** encountered invoke the conflict handler with CHANGESET_CONSTRAINT instead.
+** Or, if pbReplace is not NULL, invoke it with CHANGESET_CONFLICT. If such
+** an invocation returns SQLITE_CHANGESET_REPLACE, set *pbReplace to true
+** before retrying. In this case the caller attempts to remove the conflicting
+** row before invoking this function again, this time with pbReplace set
+** to NULL.
+**
+** If any conflict handler returns SQLITE_CHANGESET_ABORT, this function
+** returns SQLITE_ABORT. Otherwise, if no error occurs, SQLITE_OK is
+** returned.
+*/
+static int sessionApplyOneOp(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  SessionApplyCtx *p,             /* changeset_apply() context */
+  int(*xConflict)(void *, int, sqlite3_changeset_iter *),
+  void *pCtx,                     /* First argument for the conflict handler */
+  int *pbReplace,                 /* OUT: True to remove PK row and retry */
+  int *pbRetry                    /* OUT: True to retry. */
+){
+  const char *zDummy;
+  int op;
+  int nCol;
+  int rc = SQLITE_OK;
+
+  assert( p->pDelete && p->pInsert && p->pSelect );
+  assert( p->azCol && p->abPK );
+  assert( !pbReplace || *pbReplace==0 );
+
+  sqlite3changeset_op(pIter, &zDummy, &nCol, &op, 0);
+
+  if( op==SQLITE_DELETE ){
+
+    /* Bind values to the DELETE statement. If conflict handling is required,
+    ** bind values for all columns and set bound variable (nCol+1) to true.
+    ** Or, if conflict handling is not required, bind just the PK column
+    ** values and, if it exists, set (nCol+1) to false. Conflict handling
+    ** is not required if:
+    **
+    **   * this is a patchset, or
+    **   * (pbRetry==0), or
+    **   * all columns of the table are PK columns (in this case there is
+    **     no (nCol+1) variable to bind to).
+    */
+    u8 *abPK = (pIter->bPatchset ? p->abPK : 0);
+    rc = sessionBindRow(pIter, sqlite3changeset_old, nCol, abPK, p->pDelete);
+    if( rc==SQLITE_OK && sqlite3_bind_parameter_count(p->pDelete)>nCol ){
+      rc = sqlite3_bind_int(p->pDelete, nCol+1, (pbRetry==0 || abPK));
+    }
+    if( rc!=SQLITE_OK ) return rc;
+
+    sqlite3_step(p->pDelete);
+    rc = sqlite3_reset(p->pDelete);
+    if( rc==SQLITE_OK && sqlite3_changes(p->db)==0 && p->bIgnoreNoop==0 ){
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_DATA, p, pIter, xConflict, pCtx, pbRetry
+      );
+    }else if( (rc&0xff)==SQLITE_CONSTRAINT ){
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_CONFLICT, p, pIter, xConflict, pCtx, 0
+      );
+    }
+
+  }else if( op==SQLITE_UPDATE ){
+    int i;
+    sqlite3_stmt *pUp = 0;
+    int bPatchset = (pbRetry==0 || pIter->bPatchset);
+
+    rc = sessionUpdateFind(pIter, p, bPatchset, &pUp);
+
+    /* Bind values to the UPDATE statement. */
+    for(i=0; rc==SQLITE_OK && i<nCol; i++){
+      sqlite3_value *pOld = sessionChangesetOld(pIter, i);
+      sqlite3_value *pNew = sessionChangesetNew(pIter, i);
+      if( p->abPK[i] || (bPatchset==0 && pOld) ){
+        rc = sessionBindValue(pUp, i*2+2, pOld);
+      }
+      if( rc==SQLITE_OK && pNew ){
+        rc = sessionBindValue(pUp, i*2+1, pNew);
+      }
+    }
+    if( rc!=SQLITE_OK ) return rc;
+
+    /* Attempt the UPDATE. In the case of a NOTFOUND or DATA conflict,
+    ** the result will be SQLITE_OK with 0 rows modified. */
+    sqlite3_step(pUp);
+    rc = sqlite3_reset(pUp);
+
+    if( rc==SQLITE_OK && sqlite3_changes(p->db)==0 ){
+      /* A NOTFOUND or DATA error. Search the table to see if it contains
+      ** a row with a matching primary key. If so, this is a DATA conflict.
+      ** Otherwise, if there is no primary key match, it is a NOTFOUND. */
+
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_DATA, p, pIter, xConflict, pCtx, pbRetry
+      );
+
+    }else if( (rc&0xff)==SQLITE_CONSTRAINT ){
+      /* This is always a CONSTRAINT conflict. */
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_CONFLICT, p, pIter, xConflict, pCtx, 0
+      );
+    }
+
+  }else{
+    assert( op==SQLITE_INSERT );
+    if( p->bStat1 ){
+      /* Check if there is a conflicting row. For sqlite_stat1, this needs
+      ** to be done using a SELECT, as there is no PRIMARY KEY in the
+      ** database schema to throw an exception if a duplicate is inserted.  */
+      rc = sessionSeekToRow(pIter, p);
+      if( rc==SQLITE_ROW ){
+        rc = SQLITE_CONSTRAINT;
+        sqlite3_reset(p->pSelect);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = sessionBindRow(pIter, sqlite3changeset_new, nCol, 0, p->pInsert);
+      if( rc!=SQLITE_OK ) return rc;
+
+      sqlite3_step(p->pInsert);
+      rc = sqlite3_reset(p->pInsert);
+    }
+
+    if( (rc&0xff)==SQLITE_CONSTRAINT ){
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_CONFLICT, p, pIter, xConflict, pCtx, pbReplace
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Attempt to apply the change that the iterator passed as the first argument
+** currently points to to the database. If a conflict is encountered, invoke
+** the conflict handler callback.
+**
+** The difference between this function and sessionApplyOne() is that this
+** function handles the case where the conflict-handler is invoked and
+** returns SQLITE_CHANGESET_REPLACE - indicating that the change should be
+** retried in some manner.
+*/
+static int sessionApplyOneWithRetry(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator to read change from */
+  SessionApplyCtx *pApply,        /* Apply context */
+  int(*xConflict)(void*, int, sqlite3_changeset_iter*),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  int bReplace = 0;
+  int bRetry = 0;
+  int rc;
+
+  rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, &bReplace, &bRetry);
+  if( rc==SQLITE_OK ){
+    /* If the bRetry flag is set, the change has not been applied due to an
+    ** SQLITE_CHANGESET_DATA problem (i.e. this is an UPDATE or DELETE and
+    ** a row with the correct PK is present in the db, but one or more other
+    ** fields do not contain the expected values) and the conflict handler
+    ** returned SQLITE_CHANGESET_REPLACE. In this case retry the operation,
+    ** but pass NULL as the final argument so that sessionApplyOneOp() ignores
+    ** the SQLITE_CHANGESET_DATA problem.  */
+    if( bRetry ){
+      assert( pIter->op==SQLITE_UPDATE || pIter->op==SQLITE_DELETE );
+      rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, 0, 0);
+    }
+
+    /* If the bReplace flag is set, the change is an INSERT that has not
+    ** been performed because the database already contains a row with the
+    ** specified primary key and the conflict handler returned
+    ** SQLITE_CHANGESET_REPLACE. In this case remove the conflicting row
+    ** before reattempting the INSERT.  */
+    else if( bReplace ){
+      assert( pIter->op==SQLITE_INSERT );
+      rc = sqlite3_exec(db, "SAVEPOINT replace_op", 0, 0, 0);
+      if( rc==SQLITE_OK ){
+        rc = sessionBindRow(pIter,
+            sqlite3changeset_new, pApply->nCol, pApply->abPK, pApply->pDelete);
+        sqlite3_bind_int(pApply->pDelete, pApply->nCol+1, 1);
+      }
+      if( rc==SQLITE_OK ){
+        sqlite3_step(pApply->pDelete);
+        rc = sqlite3_reset(pApply->pDelete);
+      }
+      if( rc==SQLITE_OK ){
+        rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, 0, 0);
+      }
+      if( rc==SQLITE_OK ){
+        rc = sqlite3_exec(db, "RELEASE replace_op", 0, 0, 0);
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Retry the changes accumulated in the pApply->constraints buffer.
+*/
+static int sessionRetryConstraints(
+  sqlite3 *db,
+  int bPatchset,
+  const char *zTab,
+  SessionApplyCtx *pApply,
+  int(*xConflict)(void*, int, sqlite3_changeset_iter*),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  int rc = SQLITE_OK;
+
+  while( pApply->constraints.nBuf ){
+    sqlite3_changeset_iter *pIter2 = 0;
+    SessionBuffer cons = pApply->constraints;
+    memset(&pApply->constraints, 0, sizeof(SessionBuffer));
+
+    rc = sessionChangesetStart(
+        &pIter2, 0, 0, cons.nBuf, cons.aBuf, pApply->bInvertConstraints, 1
+    );
+    if( rc==SQLITE_OK ){
+      size_t nByte = 2*pApply->nCol*sizeof(sqlite3_value*);
+      int rc2;
+      pIter2->bPatchset = bPatchset;
+      pIter2->zTab = (char*)zTab;
+      pIter2->nCol = pApply->nCol;
+      pIter2->abPK = pApply->abPK;
+      sessionBufferGrow(&pIter2->tblhdr, nByte, &rc);
+      pIter2->apValue = (sqlite3_value**)pIter2->tblhdr.aBuf;
+      if( rc==SQLITE_OK ) memset(pIter2->apValue, 0, nByte);
+
+      while( rc==SQLITE_OK && SQLITE_ROW==sqlite3changeset_next(pIter2) ){
+        rc = sessionApplyOneWithRetry(db, pIter2, pApply, xConflict, pCtx);
+      }
+
+      rc2 = sqlite3changeset_finalize(pIter2);
+      if( rc==SQLITE_OK ) rc = rc2;
+    }
+    assert( pApply->bDeferConstraints || pApply->constraints.nBuf==0 );
+
+    sqlite3_free(cons.aBuf);
+    if( rc!=SQLITE_OK ) break;
+    if( pApply->constraints.nBuf>=cons.nBuf ){
+      /* No progress was made on the last round. */
+      pApply->bDeferConstraints = 0;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Argument pIter is a changeset iterator that has been initialized, but
+** not yet passed to sqlite3changeset_next(). This function applies the
+** changeset to the main database attached to handle "db". The supplied
+** conflict handler callback is invoked to resolve any conflicts encountered
+** while applying the change.
+*/
+static int sessionChangesetApply(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  sqlite3_changeset_iter *pIter,  /* Changeset to apply */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of fifth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase, /* OUT: Rebase information */
+  int flags                       /* SESSION_APPLY_XXX flags */
+){
+  int schemaMismatch = 0;
+  int rc = SQLITE_OK;             /* Return code */
+  const char *zTab = 0;           /* Name of current table */
+  int nTab = 0;                   /* Result of sqlite3Strlen30(zTab) */
+  SessionApplyCtx sApply;         /* changeset_apply() context object */
+  int bPatchset;
+  u64 savedFlag = db->flags & SQLITE_FkNoAction;
+
+  assert( xConflict!=0 );
+
+  sqlite3_mutex_enter(sqlite3_db_mutex(db));
+  if( flags & SQLITE_CHANGESETAPPLY_FKNOACTION ){
+    db->flags |= ((u64)SQLITE_FkNoAction);
+    db->aDb[0].pSchema->schema_cookie -= 32;
+  }
+
+  pIter->in.bNoDiscard = 1;
+  memset(&sApply, 0, sizeof(sApply));
+  sApply.bRebase = (ppRebase && pnRebase);
+  sApply.bInvertConstraints = !!(flags & SQLITE_CHANGESETAPPLY_INVERT);
+  sApply.bIgnoreNoop = !!(flags & SQLITE_CHANGESETAPPLY_IGNORENOOP);
+  if( (flags & SQLITE_CHANGESETAPPLY_NOSAVEPOINT)==0 ){
+    rc = sqlite3_exec(db, "SAVEPOINT changeset_apply", 0, 0, 0);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_exec(db, "PRAGMA defer_foreign_keys = 1", 0, 0, 0);
+  }
+  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3changeset_next(pIter) ){
+    int nCol;
+    int op;
+    const char *zNew;
+
+    sqlite3changeset_op(pIter, &zNew, &nCol, &op, 0);
+
+    if( zTab==0 || sqlite3_strnicmp(zNew, zTab, nTab+1) ){
+      u8 *abPK;
+
+      rc = sessionRetryConstraints(
+          db, pIter->bPatchset, zTab, &sApply, xConflict, pCtx
+      );
+      if( rc!=SQLITE_OK ) break;
+
+      sessionUpdateFree(&sApply);
+      sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
+      sqlite3_finalize(sApply.pDelete);
+      sqlite3_finalize(sApply.pInsert);
+      sqlite3_finalize(sApply.pSelect);
+      sApply.db = db;
+      sApply.pDelete = 0;
+      sApply.pInsert = 0;
+      sApply.pSelect = 0;
+      sApply.nCol = 0;
+      sApply.azCol = 0;
+      sApply.abPK = 0;
+      sApply.bStat1 = 0;
+      sApply.bDeferConstraints = 1;
+      sApply.bRebaseStarted = 0;
+      sApply.bRowid = 0;
+      memset(&sApply.constraints, 0, sizeof(SessionBuffer));
+
+      /* If an xFilter() callback was specified, invoke it now. If the
+      ** xFilter callback returns zero, skip this table. If it returns
+      ** non-zero, proceed. */
+      schemaMismatch = (xFilter && (0==xFilter(pCtx, zNew)));
+      if( schemaMismatch ){
+        zTab = sqlite3_mprintf("%s", zNew);
+        if( zTab==0 ){
+          rc = SQLITE_NOMEM;
+          break;
+        }
+        nTab = (int)strlen(zTab);
+        sApply.azCol = (const char **)zTab;
+      }else{
+        int nMinCol = 0;
+        int i;
+
+        sqlite3changeset_pk(pIter, &abPK, 0);
+        rc = sessionTableInfo(0, db, "main", zNew,
+            &sApply.nCol, 0, &zTab, &sApply.azCol, 0, 0,
+            &sApply.abPK, &sApply.bRowid
+        );
+        if( rc!=SQLITE_OK ) break;
+        for(i=0; i<sApply.nCol; i++){
+          if( sApply.abPK[i] ) nMinCol = i+1;
+        }
+
+        if( sApply.nCol==0 ){
+          schemaMismatch = 1;
+          sqlite3_log(SQLITE_SCHEMA,
+              "sqlite3changeset_apply(): no such table: %s", zTab
+          );
+        }
+        else if( sApply.nCol<nCol ){
+          schemaMismatch = 1;
+          sqlite3_log(SQLITE_SCHEMA,
+              "sqlite3changeset_apply(): table %s has %d columns, "
+              "expected %d or more",
+              zTab, sApply.nCol, nCol
+          );
+        }
+        else if( nCol<nMinCol || memcmp(sApply.abPK, abPK, nCol)!=0 ){
+          schemaMismatch = 1;
+          sqlite3_log(SQLITE_SCHEMA, "sqlite3changeset_apply(): "
+              "primary key mismatch for table %s", zTab
+          );
+        }
+        else{
+          sApply.nCol = nCol;
+          if( 0==sqlite3_stricmp(zTab, "sqlite_stat1") ){
+            if( (rc = sessionStat1Sql(db, &sApply) ) ){
+              break;
+            }
+            sApply.bStat1 = 1;
+          }else{
+            if( (rc = sessionSelectRow(db, zTab, &sApply))
+             || (rc = sessionDeleteRow(db, zTab, &sApply))
+             || (rc = sessionInsertRow(db, zTab, &sApply))
+            ){
+              break;
+            }
+            sApply.bStat1 = 0;
+          }
+        }
+        nTab = sqlite3Strlen30(zTab);
+      }
+    }
+
+    /* If there is a schema mismatch on the current table, proceed to the
+    ** next change. A log message has already been issued. */
+    if( schemaMismatch ) continue;
+
+    rc = sessionApplyOneWithRetry(db, pIter, &sApply, xConflict, pCtx);
+  }
+
+  bPatchset = pIter->bPatchset;
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changeset_finalize(pIter);
+  }else{
+    sqlite3changeset_finalize(pIter);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sessionRetryConstraints(db, bPatchset, zTab, &sApply, xConflict, pCtx);
+  }
+
+  if( rc==SQLITE_OK ){
+    int nFk, notUsed;
+    sqlite3_db_status(db, SQLITE_DBSTATUS_DEFERRED_FKS, &nFk, ¬Used, 0);
+    if( nFk!=0 ){
+      int res = SQLITE_CHANGESET_ABORT;
+      sqlite3_changeset_iter sIter;
+      memset(&sIter, 0, sizeof(sIter));
+      sIter.nCol = nFk;
+      res = xConflict(pCtx, SQLITE_CHANGESET_FOREIGN_KEY, &sIter);
+      if( res!=SQLITE_CHANGESET_OMIT ){
+        rc = SQLITE_CONSTRAINT;
+      }
+    }
+  }
+
+  {
+    int rc2 = sqlite3_exec(db, "PRAGMA defer_foreign_keys = 0", 0, 0, 0);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  if( (flags & SQLITE_CHANGESETAPPLY_NOSAVEPOINT)==0 ){
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3_exec(db, "ROLLBACK TO changeset_apply", 0, 0, 0);
+      sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
+    }
+  }
+
+  assert( sApply.bRebase || sApply.rebase.nBuf==0 );
+  if( rc==SQLITE_OK && bPatchset==0 && sApply.bRebase ){
+    *ppRebase = (void*)sApply.rebase.aBuf;
+    *pnRebase = sApply.rebase.nBuf;
+    sApply.rebase.aBuf = 0;
+  }
+  sessionUpdateFree(&sApply);
+  sqlite3_finalize(sApply.pInsert);
+  sqlite3_finalize(sApply.pDelete);
+  sqlite3_finalize(sApply.pSelect);
+  sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
+  sqlite3_free((char*)sApply.constraints.aBuf);
+  sqlite3_free((char*)sApply.rebase.aBuf);
+
+  if( (flags & SQLITE_CHANGESETAPPLY_FKNOACTION) && savedFlag==0 ){
+    assert( db->flags & SQLITE_FkNoAction );
+    db->flags &= ~((u64)SQLITE_FkNoAction);
+    db->aDb[0].pSchema->schema_cookie -= 32;
+  }
+  sqlite3_mutex_leave(sqlite3_db_mutex(db));
+  return rc;
+}
+
+/*
+** Apply the changeset passed via pChangeset/nChangeset to the main
+** database attached to handle "db".
+*/
+SQLITE_API int sqlite3changeset_apply_v2(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase,
+  int flags
+){
+  sqlite3_changeset_iter *pIter;  /* Iterator to skip through changeset */
+  int bInv = !!(flags & SQLITE_CHANGESETAPPLY_INVERT);
+  int rc = sessionChangesetStart(&pIter, 0, 0, nChangeset, pChangeset, bInv, 1);
+
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetApply(
+        db, pIter, xFilter, xConflict, pCtx, ppRebase, pnRebase, flags
+    );
+  }
+
+  return rc;
+}
+
+/*
+** Apply the changeset passed via pChangeset/nChangeset to the main database
+** attached to handle "db". Invoke the supplied conflict handler callback
+** to resolve any conflicts encountered while applying the change.
+*/
+SQLITE_API int sqlite3changeset_apply(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of fifth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  return sqlite3changeset_apply_v2(
+      db, nChangeset, pChangeset, xFilter, xConflict, pCtx, 0, 0, 0
+  );
+}
+
+/*
+** Apply the changeset passed via xInput/pIn to the main database
+** attached to handle "db". Invoke the supplied conflict handler callback
+** to resolve any conflicts encountered while applying the change.
+*/
+SQLITE_API int sqlite3changeset_apply_v2_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase,
+  int flags
+){
+  sqlite3_changeset_iter *pIter;  /* Iterator to skip through changeset */
+  int bInverse = !!(flags & SQLITE_CHANGESETAPPLY_INVERT);
+  int rc = sessionChangesetStart(&pIter, xInput, pIn, 0, 0, bInverse, 1);
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetApply(
+        db, pIter, xFilter, xConflict, pCtx, ppRebase, pnRebase, flags
+    );
+  }
+  return rc;
+}
+SQLITE_API int sqlite3changeset_apply_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  return sqlite3changeset_apply_v2_strm(
+      db, xInput, pIn, xFilter, xConflict, pCtx, 0, 0, 0
+  );
+}
+
+/*
+** sqlite3_changegroup handle.
+*/
+struct sqlite3_changegroup {
+  int rc;                         /* Error code */
+  int bPatch;                     /* True to accumulate patchsets */
+  SessionTable *pList;            /* List of tables in current patch */
+  SessionBuffer rec;
+
+  sqlite3 *db;                    /* Configured by changegroup_schema() */
+  char *zDb;                      /* Configured by changegroup_schema() */
+};
+
+/*
+** This function is called to merge two changes to the same row together as
+** part of an sqlite3changeset_concat() operation. A new change object is
+** allocated and a pointer to it stored in *ppNew.
+*/
+static int sessionChangeMerge(
+  SessionTable *pTab,             /* Table structure */
+  int bRebase,                    /* True for a rebase hash-table */
+  int bPatchset,                  /* True for patchsets */
+  SessionChange *pExist,          /* Existing change */
+  int op2,                        /* Second change operation */
+  int bIndirect,                  /* True if second change is indirect */
+  u8 *aRec,                       /* Second change record */
+  int nRec,                       /* Number of bytes in aRec */
+  SessionChange **ppNew           /* OUT: Merged change */
+){
+  SessionChange *pNew = 0;
+  int rc = SQLITE_OK;
+  assert( aRec!=0 );
+
+  if( !pExist ){
+    pNew = (SessionChange *)sqlite3_malloc64(sizeof(SessionChange) + nRec);
+    if( !pNew ){
+      return SQLITE_NOMEM;
+    }
+    memset(pNew, 0, sizeof(SessionChange));
+    pNew->op = op2;
+    pNew->bIndirect = bIndirect;
+    pNew->aRecord = (u8*)&pNew[1];
+    if( bIndirect==0 || bRebase==0 ){
+      pNew->nRecord = nRec;
+      memcpy(pNew->aRecord, aRec, nRec);
+    }else{
+      int i;
+      u8 *pIn = aRec;
+      u8 *pOut = pNew->aRecord;
+      for(i=0; i<pTab->nCol; i++){
+        int nIn = sessionSerialLen(pIn);
+        if( *pIn==0 ){
+          *pOut++ = 0;
+        }else if( pTab->abPK[i]==0 ){
+          *pOut++ = 0xFF;
+        }else{
+          memcpy(pOut, pIn, nIn);
+          pOut += nIn;
+        }
+        pIn += nIn;
+      }
+      pNew->nRecord = pOut - pNew->aRecord;
+    }
+  }else if( bRebase ){
+    if( pExist->op==SQLITE_DELETE && pExist->bIndirect ){
+      *ppNew = pExist;
+    }else{
+      sqlite3_int64 nByte = nRec + pExist->nRecord + sizeof(SessionChange);
+      pNew = (SessionChange*)sqlite3_malloc64(nByte);
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        int i;
+        u8 *a1 = pExist->aRecord;
+        u8 *a2 = aRec;
+        u8 *pOut;
+
+        memset(pNew, 0, nByte);
+        pNew->bIndirect = bIndirect || pExist->bIndirect;
+        pNew->op = op2;
+        pOut = pNew->aRecord = (u8*)&pNew[1];
+
+        for(i=0; i<pTab->nCol; i++){
+          int n1 = sessionSerialLen(a1);
+          int n2 = sessionSerialLen(a2);
+          if( *a1==0xFF || (pTab->abPK[i]==0 && bIndirect) ){
+            *pOut++ = 0xFF;
+          }else if( *a2==0 ){
+            memcpy(pOut, a1, n1);
+            pOut += n1;
+          }else{
+            memcpy(pOut, a2, n2);
+            pOut += n2;
+          }
+          a1 += n1;
+          a2 += n2;
+        }
+        pNew->nRecord = pOut - pNew->aRecord;
+      }
+      sqlite3_free(pExist);
+    }
+  }else{
+    int op1 = pExist->op;
+
+    /*
+    **   op1=INSERT, op2=INSERT      ->      Unsupported. Discard op2.
+    **   op1=INSERT, op2=UPDATE      ->      INSERT.
+    **   op1=INSERT, op2=DELETE      ->      (none)
+    **
+    **   op1=UPDATE, op2=INSERT      ->      Unsupported. Discard op2.
+    **   op1=UPDATE, op2=UPDATE      ->      UPDATE.
+    **   op1=UPDATE, op2=DELETE      ->      DELETE.
+    **
+    **   op1=DELETE, op2=INSERT      ->      UPDATE.
+    **   op1=DELETE, op2=UPDATE      ->      Unsupported. Discard op2.
+    **   op1=DELETE, op2=DELETE      ->      Unsupported. Discard op2.
+    */
+    if( (op1==SQLITE_INSERT && op2==SQLITE_INSERT)
+     || (op1==SQLITE_UPDATE && op2==SQLITE_INSERT)
+     || (op1==SQLITE_DELETE && op2==SQLITE_UPDATE)
+     || (op1==SQLITE_DELETE && op2==SQLITE_DELETE)
+    ){
+      pNew = pExist;
+    }else if( op1==SQLITE_INSERT && op2==SQLITE_DELETE ){
+      sqlite3_free(pExist);
+      assert( pNew==0 );
+    }else{
+      u8 *aExist = pExist->aRecord;
+      sqlite3_int64 nByte;
+      u8 *aCsr;
+
+      /* Allocate a new SessionChange object. Ensure that the aRecord[]
+      ** buffer of the new object is large enough to hold any record that
+      ** may be generated by combining the input records.  */
+      nByte = sizeof(SessionChange) + pExist->nRecord + nRec;
+      pNew = (SessionChange *)sqlite3_malloc64(nByte);
+      if( !pNew ){
+        sqlite3_free(pExist);
+        return SQLITE_NOMEM;
+      }
+      memset(pNew, 0, sizeof(SessionChange));
+      pNew->bIndirect = (bIndirect && pExist->bIndirect);
+      aCsr = pNew->aRecord = (u8 *)&pNew[1];
+
+      if( op1==SQLITE_INSERT ){             /* INSERT + UPDATE */
+        u8 *a1 = aRec;
+        assert( op2==SQLITE_UPDATE );
+        pNew->op = SQLITE_INSERT;
+        if( bPatchset==0 ) sessionSkipRecord(&a1, pTab->nCol);
+        sessionMergeRecord(&aCsr, pTab->nCol, aExist, a1);
+      }else if( op1==SQLITE_DELETE ){       /* DELETE + INSERT */
+        assert( op2==SQLITE_INSERT );
+        pNew->op = SQLITE_UPDATE;
+        if( bPatchset ){
+          memcpy(aCsr, aRec, nRec);
+          aCsr += nRec;
+        }else{
+          if( 0==sessionMergeUpdate(&aCsr, pTab, bPatchset, aExist, 0,aRec,0) ){
+            sqlite3_free(pNew);
+            pNew = 0;
+          }
+        }
+      }else if( op2==SQLITE_UPDATE ){       /* UPDATE + UPDATE */
+        u8 *a1 = aExist;
+        u8 *a2 = aRec;
+        assert( op1==SQLITE_UPDATE );
+        if( bPatchset==0 ){
+          sessionSkipRecord(&a1, pTab->nCol);
+          sessionSkipRecord(&a2, pTab->nCol);
+        }
+        pNew->op = SQLITE_UPDATE;
+        if( 0==sessionMergeUpdate(&aCsr, pTab, bPatchset, aRec, aExist,a1,a2) ){
+          sqlite3_free(pNew);
+          pNew = 0;
+        }
+      }else{                                /* UPDATE + DELETE */
+        assert( op1==SQLITE_UPDATE && op2==SQLITE_DELETE );
+        pNew->op = SQLITE_DELETE;
+        if( bPatchset ){
+          memcpy(aCsr, aRec, nRec);
+          aCsr += nRec;
+        }else{
+          sessionMergeRecord(&aCsr, pTab->nCol, aRec, aExist);
+        }
+      }
+
+      if( pNew ){
+        pNew->nRecord = (int)(aCsr - pNew->aRecord);
+      }
+      sqlite3_free(pExist);
+    }
+  }
+
+  *ppNew = pNew;
+  return rc;
+}
+
+/*
+** Check if a changeset entry with nCol columns and the PK array passed
+** as the final argument to this function is compatible with SessionTable
+** pTab. If so, return 1. Otherwise, if they are incompatible in some way,
+** return 0.
+*/
+static int sessionChangesetCheckCompat(
+  SessionTable *pTab,
+  int nCol,
+  u8 *abPK
+){
+  if( pTab->azCol && nCol<pTab->nCol ){
+    int ii;
+    for(ii=0; ii<pTab->nCol; ii++){
+      u8 bPK = (ii < nCol) ? abPK[ii] : 0;
+      if( pTab->abPK[ii]!=bPK ) return 0;
+    }
+    return 1;
+  }
+  return (pTab->nCol==nCol && 0==memcmp(abPK, pTab->abPK, nCol));
+}
+
+static int sessionChangesetExtendRecord(
+  sqlite3_changegroup *pGrp,
+  SessionTable *pTab,
+  int nCol,
+  int op,
+  const u8 *aRec,
+  int nRec,
+  SessionBuffer *pOut
+){
+  int rc = SQLITE_OK;
+  int ii = 0;
+
+  assert( pTab->azCol );
+  assert( nCol<pTab->nCol );
+
+  pOut->nBuf = 0;
+  if( op==SQLITE_INSERT || (op==SQLITE_DELETE && pGrp->bPatch==0) ){
+    /* Append the missing default column values to the record. */
+    sessionAppendBlob(pOut, aRec, nRec, &rc);
+    if( rc==SQLITE_OK && pTab->pDfltStmt==0 ){
+      rc = sessionPrepareDfltStmt(pGrp->db, pTab, &pTab->pDfltStmt);
+      if( rc==SQLITE_OK && SQLITE_ROW!=sqlite3_step(pTab->pDfltStmt) ){
+        rc = sqlite3_errcode(pGrp->db);
+      }
+    }
+    for(ii=nCol; rc==SQLITE_OK && ii<pTab->nCol; ii++){
+      int eType = sqlite3_column_type(pTab->pDfltStmt, ii);
+      sessionAppendByte(pOut, eType, &rc);
+      switch( eType ){
+        case SQLITE_FLOAT:
+        case SQLITE_INTEGER: {
+          i64 iVal;
+          if( eType==SQLITE_INTEGER ){
+            iVal = sqlite3_column_int64(pTab->pDfltStmt, ii);
+          }else{
+            double rVal = sqlite3_column_int64(pTab->pDfltStmt, ii);
+            memcpy(&iVal, &rVal, sizeof(i64));
+          }
+          if( SQLITE_OK==sessionBufferGrow(pOut, 8, &rc) ){
+            sessionPutI64(&pOut->aBuf[pOut->nBuf], iVal);
+            pOut->nBuf += 8;
+          }
+          break;
+        }
+
+        case SQLITE_BLOB:
+        case SQLITE_TEXT: {
+          int n = sqlite3_column_bytes(pTab->pDfltStmt, ii);
+          sessionAppendVarint(pOut, n, &rc);
+          if( eType==SQLITE_TEXT ){
+            const u8 *z = (const u8*)sqlite3_column_text(pTab->pDfltStmt, ii);
+            sessionAppendBlob(pOut, z, n, &rc);
+          }else{
+            const u8 *z = (const u8*)sqlite3_column_blob(pTab->pDfltStmt, ii);
+            sessionAppendBlob(pOut, z, n, &rc);
+          }
+          break;
+        }
+
+        default:
+          assert( eType==SQLITE_NULL );
+          break;
+      }
+    }
+  }else if( op==SQLITE_UPDATE ){
+    /* Append missing "undefined" entries to the old.* record. And, if this
+    ** is an UPDATE, to the new.* record as well.  */
+    int iOff = 0;
+    if( pGrp->bPatch==0 ){
+      for(ii=0; ii<nCol; ii++){
+        iOff += sessionSerialLen(&aRec[iOff]);
+      }
+      sessionAppendBlob(pOut, aRec, iOff, &rc);
+      for(ii=0; ii<(pTab->nCol-nCol); ii++){
+        sessionAppendByte(pOut, 0x00, &rc);
+      }
+    }
+
+    sessionAppendBlob(pOut, &aRec[iOff], nRec-iOff, &rc);
+    for(ii=0; ii<(pTab->nCol-nCol); ii++){
+      sessionAppendByte(pOut, 0x00, &rc);
+    }
+  }else{
+    assert( op==SQLITE_DELETE && pGrp->bPatch );
+    sessionAppendBlob(pOut, aRec, nRec, &rc);
+  }
+
+  return rc;
+}
+
+/*
+** Locate or create a SessionTable object that may be used to add the
+** change currently pointed to by iterator pIter to changegroup pGrp.
+** If successful, set output variable (*ppTab) to point to the table
+** object and return SQLITE_OK. Otherwise, if some error occurs, return
+** an SQLite error code and leave (*ppTab) set to NULL.
+*/
+static int sessionChangesetFindTable(
+  sqlite3_changegroup *pGrp,
+  const char *zTab,
+  sqlite3_changeset_iter *pIter,
+  SessionTable **ppTab
+){
+  int rc = SQLITE_OK;
+  SessionTable *pTab = 0;
+  int nTab = (int)strlen(zTab);
+  u8 *abPK = 0;
+  int nCol = 0;
+
+  *ppTab = 0;
+  sqlite3changeset_pk(pIter, &abPK, &nCol);
+
+  /* Search the list for an existing table */
+  for(pTab = pGrp->pList; pTab; pTab=pTab->pNext){
+    if( 0==sqlite3_strnicmp(pTab->zName, zTab, nTab+1) ) break;
+  }
+
+  /* If one was not found above, create a new table now */
+  if( !pTab ){
+    SessionTable **ppNew;
+
+    pTab = sqlite3_malloc64(sizeof(SessionTable) + nCol + nTab+1);
+    if( !pTab ){
+      return SQLITE_NOMEM;
+    }
+    memset(pTab, 0, sizeof(SessionTable));
+    pTab->nCol = nCol;
+    pTab->abPK = (u8*)&pTab[1];
+    memcpy(pTab->abPK, abPK, nCol);
+    pTab->zName = (char*)&pTab->abPK[nCol];
+    memcpy(pTab->zName, zTab, nTab+1);
+
+    if( pGrp->db ){
+      pTab->nCol = 0;
+      rc = sessionInitTable(0, pTab, pGrp->db, pGrp->zDb);
+      if( rc ){
+        assert( pTab->azCol==0 );
+        sqlite3_free(pTab);
+        return rc;
+      }
+    }
+
+    /* The new object must be linked on to the end of the list, not
+    ** simply added to the start of it. This is to ensure that the
+    ** tables within the output of sqlite3changegroup_output() are in
+    ** the right order.  */
+    for(ppNew=&pGrp->pList; *ppNew; ppNew=&(*ppNew)->pNext);
+    *ppNew = pTab;
+  }
+
+  /* Check that the table is compatible. */
+  if( !sessionChangesetCheckCompat(pTab, nCol, abPK) ){
+    rc = SQLITE_SCHEMA;
+  }
+
+  *ppTab = pTab;
+  return rc;
+}
+
+/*
+** Add the change currently indicated by iterator pIter to the hash table
+** belonging to changegroup pGrp.
+*/
+static int sessionOneChangeToHash(
+  sqlite3_changegroup *pGrp,
+  sqlite3_changeset_iter *pIter,
+  int bRebase
+){
+  int rc = SQLITE_OK;
+  int nCol = 0;
+  int op = 0;
+  int iHash = 0;
+  int bIndirect = 0;
+  SessionChange *pChange = 0;
+  SessionChange *pExist = 0;
+  SessionChange **pp = 0;
+  SessionTable *pTab = 0;
+  u8 *aRec = &pIter->in.aData[pIter->in.iCurrent + 2];
+  int nRec = (pIter->in.iNext - pIter->in.iCurrent) - 2;
+
+  assert( nRec>0 );
+
+  /* Ensure that only changesets, or only patchsets, but not a mixture
+  ** of both, are being combined. It is an error to try to combine a
+  ** changeset and a patchset.  */
+  if( pGrp->pList==0 ){
+    pGrp->bPatch = pIter->bPatchset;
+  }else if( pIter->bPatchset!=pGrp->bPatch ){
+    rc = SQLITE_ERROR;
+  }
+
+  if( rc==SQLITE_OK ){
+    const char *zTab = 0;
+    sqlite3changeset_op(pIter, &zTab, &nCol, &op, &bIndirect);
+    rc = sessionChangesetFindTable(pGrp, zTab, pIter, &pTab);
+  }
+
+  if( rc==SQLITE_OK && nCol<pTab->nCol ){
+    SessionBuffer *pBuf = &pGrp->rec;
+    rc = sessionChangesetExtendRecord(pGrp, pTab, nCol, op, aRec, nRec, pBuf);
+    aRec = pBuf->aBuf;
+    nRec = pBuf->nBuf;
+    assert( pGrp->db );
+  }
+
+  if( rc==SQLITE_OK && sessionGrowHash(0, pIter->bPatchset, pTab) ){
+    rc = SQLITE_NOMEM;
+  }
+
+  if( rc==SQLITE_OK ){
+    /* Search for existing entry. If found, remove it from the hash table.
+    ** Code below may link it back in.  */
+    iHash = sessionChangeHash(
+        pTab, (pIter->bPatchset && op==SQLITE_DELETE), aRec, pTab->nChange
+    );
+    for(pp=&pTab->apChange[iHash]; *pp; pp=&(*pp)->pNext){
+      int bPkOnly1 = 0;
+      int bPkOnly2 = 0;
+      if( pIter->bPatchset ){
+        bPkOnly1 = (*pp)->op==SQLITE_DELETE;
+        bPkOnly2 = op==SQLITE_DELETE;
+      }
+      if( sessionChangeEqual(pTab, bPkOnly1, (*pp)->aRecord, bPkOnly2, aRec) ){
+        pExist = *pp;
+        *pp = (*pp)->pNext;
+        pTab->nEntry--;
+        break;
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sessionChangeMerge(pTab, bRebase,
+        pIter->bPatchset, pExist, op, bIndirect, aRec, nRec, &pChange
+    );
+  }
+  if( rc==SQLITE_OK && pChange ){
+    pChange->pNext = pTab->apChange[iHash];
+    pTab->apChange[iHash] = pChange;
+    pTab->nEntry++;
+  }
+
+  if( rc==SQLITE_OK ) rc = pIter->rc;
+  return rc;
+}
+
+/*
+** Add all changes in the changeset traversed by the iterator passed as
+** the first argument to the changegroup hash tables.
+*/
+static int sessionChangesetToHash(
+  sqlite3_changeset_iter *pIter,   /* Iterator to read from */
+  sqlite3_changegroup *pGrp,       /* Changegroup object to add changeset to */
+  int bRebase                      /* True if hash table is for rebasing */
+){
+  u8 *aRec;
+  int nRec;
+  int rc = SQLITE_OK;
+
+  pIter->in.bNoDiscard = 1;
+  while( SQLITE_ROW==(sessionChangesetNext(pIter, &aRec, &nRec, 0)) ){
+    rc = sessionOneChangeToHash(pGrp, pIter, bRebase);
+    if( rc!=SQLITE_OK ) break;
+  }
+
+  if( rc==SQLITE_OK ) rc = pIter->rc;
+  return rc;
+}
+
+/*
+** Serialize a changeset (or patchset) based on all changesets (or patchsets)
+** added to the changegroup object passed as the first argument.
+**
+** If xOutput is not NULL, then the changeset/patchset is returned to the
+** user via one or more calls to xOutput, as with the other streaming
+** interfaces.
+**
+** Or, if xOutput is NULL, then (*ppOut) is populated with a pointer to a
+** buffer containing the output changeset before this function returns. In
+** this case (*pnOut) is set to the size of the output buffer in bytes. It
+** is the responsibility of the caller to free the output buffer using
+** sqlite3_free() when it is no longer required.
+**
+** If successful, SQLITE_OK is returned. Or, if an error occurs, an SQLite
+** error code. If an error occurs and xOutput is NULL, (*ppOut) and (*pnOut)
+** are both set to 0 before returning.
+*/
+static int sessionChangegroupOutput(
+  sqlite3_changegroup *pGrp,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut,
+  int *pnOut,
+  void **ppOut
+){
+  int rc = SQLITE_OK;
+  SessionBuffer buf = {0, 0, 0};
+  SessionTable *pTab;
+  assert( xOutput==0 || (ppOut==0 && pnOut==0) );
+
+  /* Create the serialized output changeset based on the contents of the
+  ** hash tables attached to the SessionTable objects in list p->pList.
+  */
+  for(pTab=pGrp->pList; rc==SQLITE_OK && pTab; pTab=pTab->pNext){
+    int i;
+    if( pTab->nEntry==0 ) continue;
+
+    sessionAppendTableHdr(&buf, pGrp->bPatch, pTab, &rc);
+    for(i=0; i<pTab->nChange; i++){
+      SessionChange *p;
+      for(p=pTab->apChange[i]; p; p=p->pNext){
+        sessionAppendByte(&buf, p->op, &rc);
+        sessionAppendByte(&buf, p->bIndirect, &rc);
+        sessionAppendBlob(&buf, p->aRecord, p->nRecord, &rc);
+        if( rc==SQLITE_OK && xOutput && buf.nBuf>=sessions_strm_chunk_size ){
+          rc = xOutput(pOut, buf.aBuf, buf.nBuf);
+          buf.nBuf = 0;
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( xOutput ){
+      if( buf.nBuf>0 ) rc = xOutput(pOut, buf.aBuf, buf.nBuf);
+    }else if( ppOut ){
+      *ppOut = buf.aBuf;
+      if( pnOut ) *pnOut = buf.nBuf;
+      buf.aBuf = 0;
+    }
+  }
+  sqlite3_free(buf.aBuf);
+
+  return rc;
+}
+
+/*
+** Allocate a new, empty, sqlite3_changegroup.
+*/
+SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp){
+  int rc = SQLITE_OK;             /* Return code */
+  sqlite3_changegroup *p;         /* New object */
+  p = (sqlite3_changegroup*)sqlite3_malloc(sizeof(sqlite3_changegroup));
+  if( p==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    memset(p, 0, sizeof(sqlite3_changegroup));
+  }
+  *pp = p;
+  return rc;
+}
+
+/*
+** Provide a database schema to the changegroup object.
+*/
+SQLITE_API int sqlite3changegroup_schema(
+  sqlite3_changegroup *pGrp,
+  sqlite3 *db,
+  const char *zDb
+){
+  int rc = SQLITE_OK;
+
+  if( pGrp->pList || pGrp->db ){
+    /* Cannot add a schema after one or more calls to sqlite3changegroup_add(),
+    ** or after sqlite3changegroup_schema() has already been called. */
+    rc = SQLITE_MISUSE;
+  }else{
+    pGrp->zDb = sqlite3_mprintf("%s", zDb);
+    if( pGrp->zDb==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pGrp->db = db;
+    }
+  }
+  return rc;
+}
+
+/*
+** Add the changeset currently stored in buffer pData, size nData bytes,
+** to changeset-group p.
+*/
+SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup *pGrp, int nData, void *pData){
+  sqlite3_changeset_iter *pIter;  /* Iterator opened on pData/nData */
+  int rc;                         /* Return code */
+
+  rc = sqlite3changeset_start(&pIter, nData, pData);
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetToHash(pIter, pGrp, 0);
+  }
+  sqlite3changeset_finalize(pIter);
+  return rc;
+}
+
+/*
+** Add a single change to a changeset-group.
+*/
+SQLITE_API int sqlite3changegroup_add_change(
+  sqlite3_changegroup *pGrp,
+  sqlite3_changeset_iter *pIter
+){
+  if( pIter->in.iCurrent==pIter->in.iNext
+   || pIter->rc!=SQLITE_OK
+   || pIter->bInvert
+  ){
+    /* Iterator does not point to any valid entry or is an INVERT iterator. */
+    return SQLITE_ERROR;
+  }
+  return sessionOneChangeToHash(pGrp, pIter, 0);
+}
+
+/*
+** Obtain a buffer containing a changeset representing the concatenation
+** of all changesets added to the group so far.
+*/
+SQLITE_API int sqlite3changegroup_output(
+    sqlite3_changegroup *pGrp,
+    int *pnData,
+    void **ppData
+){
+  return sessionChangegroupOutput(pGrp, 0, 0, pnData, ppData);
+}
+
+/*
+** Streaming versions of changegroup_add().
+*/
+SQLITE_API int sqlite3changegroup_add_strm(
+  sqlite3_changegroup *pGrp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn
+){
+  sqlite3_changeset_iter *pIter;  /* Iterator opened on pData/nData */
+  int rc;                         /* Return code */
+
+  rc = sqlite3changeset_start_strm(&pIter, xInput, pIn);
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetToHash(pIter, pGrp, 0);
+  }
+  sqlite3changeset_finalize(pIter);
+  return rc;
+}
+
+/*
+** Streaming versions of changegroup_output().
+*/
+SQLITE_API int sqlite3changegroup_output_strm(
+  sqlite3_changegroup *pGrp,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  return sessionChangegroupOutput(pGrp, xOutput, pOut, 0, 0);
+}
+
+/*
+** Delete a changegroup object.
+*/
+SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup *pGrp){
+  if( pGrp ){
+    sqlite3_free(pGrp->zDb);
+    sessionDeleteTable(0, pGrp->pList);
+    sqlite3_free(pGrp->rec.aBuf);
+    sqlite3_free(pGrp);
+  }
+}
+
+/*
+** Combine two changesets together.
+*/
+SQLITE_API int sqlite3changeset_concat(
+  int nLeft,                      /* Number of bytes in lhs input */
+  void *pLeft,                    /* Lhs input changeset */
+  int nRight                      /* Number of bytes in rhs input */,
+  void *pRight,                   /* Rhs input changeset */
+  int *pnOut,                     /* OUT: Number of bytes in output changeset */
+  void **ppOut                    /* OUT: changeset (left <concat> right) */
+){
+  sqlite3_changegroup *pGrp;
+  int rc;
+
+  rc = sqlite3changegroup_new(&pGrp);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_add(pGrp, nLeft, pLeft);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_add(pGrp, nRight, pRight);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
+  }
+  sqlite3changegroup_delete(pGrp);
+
+  return rc;
+}
+
+/*
+** Streaming version of sqlite3changeset_concat().
+*/
+SQLITE_API int sqlite3changeset_concat_strm(
+  int (*xInputA)(void *pIn, void *pData, int *pnData),
+  void *pInA,
+  int (*xInputB)(void *pIn, void *pData, int *pnData),
+  void *pInB,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  sqlite3_changegroup *pGrp;
+  int rc;
+
+  rc = sqlite3changegroup_new(&pGrp);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_add_strm(pGrp, xInputA, pInA);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_add_strm(pGrp, xInputB, pInB);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_output_strm(pGrp, xOutput, pOut);
+  }
+  sqlite3changegroup_delete(pGrp);
+
+  return rc;
+}
+
+/*
+** Changeset rebaser handle.
+*/
+struct sqlite3_rebaser {
+  sqlite3_changegroup grp;        /* Hash table */
+};
+
+/*
+** Buffers a1 and a2 must both contain a sessions module record nCol
+** fields in size. This function appends an nCol sessions module
+** record to buffer pBuf that is a copy of a1, except that for
+** each field that is undefined in a1[], swap in the field from a2[].
+*/
+static void sessionAppendRecordMerge(
+  SessionBuffer *pBuf,            /* Buffer to append to */
+  int nCol,                       /* Number of columns in each record */
+  u8 *a1, int n1,                 /* Record 1 */
+  u8 *a2, int n2,                 /* Record 2 */
+  int *pRc                        /* IN/OUT: error code */
+){
+  sessionBufferGrow(pBuf, n1+n2, pRc);
+  if( *pRc==SQLITE_OK ){
+    int i;
+    u8 *pOut = &pBuf->aBuf[pBuf->nBuf];
+    for(i=0; i<nCol; i++){
+      int nn1 = sessionSerialLen(a1);
+      int nn2 = sessionSerialLen(a2);
+      if( *a1==0 || *a1==0xFF ){
+        memcpy(pOut, a2, nn2);
+        pOut += nn2;
+      }else{
+        memcpy(pOut, a1, nn1);
+        pOut += nn1;
+      }
+      a1 += nn1;
+      a2 += nn2;
+    }
+
+    pBuf->nBuf = pOut-pBuf->aBuf;
+    assert( pBuf->nBuf<=pBuf->nAlloc );
+  }
+}
+
+/*
+** This function is called when rebasing a local UPDATE change against one
+** or more remote UPDATE changes. The aRec/nRec buffer contains the current
+** old.* and new.* records for the change. The rebase buffer (a single
+** record) is in aChange/nChange. The rebased change is appended to buffer
+** pBuf.
+**
+** Rebasing the UPDATE involves:
+**
+**   * Removing any changes to fields for which the corresponding field
+**     in the rebase buffer is set to "replaced" (type 0xFF). If this
+**     means the UPDATE change updates no fields, nothing is appended
+**     to the output buffer.
+**
+**   * For each field modified by the local change for which the
+**     corresponding field in the rebase buffer is not "undefined" (0x00)
+**     or "replaced" (0xFF), the old.* value is replaced by the value
+**     in the rebase buffer.
+*/
+static void sessionAppendPartialUpdate(
+  SessionBuffer *pBuf,            /* Append record here */
+  sqlite3_changeset_iter *pIter,  /* Iterator pointed at local change */
+  u8 *aRec, int nRec,             /* Local change */
+  u8 *aChange, int nChange,       /* Record to rebase against */
+  int *pRc                        /* IN/OUT: Return Code */
+){
+  sessionBufferGrow(pBuf, 2+nRec+nChange, pRc);
+  if( *pRc==SQLITE_OK ){
+    int bData = 0;
+    u8 *pOut = &pBuf->aBuf[pBuf->nBuf];
+    int i;
+    u8 *a1 = aRec;
+    u8 *a2 = aChange;
+
+    *pOut++ = SQLITE_UPDATE;
+    *pOut++ = pIter->bIndirect;
+    for(i=0; i<pIter->nCol; i++){
+      int n1 = sessionSerialLen(a1);
+      int n2 = sessionSerialLen(a2);
+      if( pIter->abPK[i] || a2[0]==0 ){
+        if( !pIter->abPK[i] && a1[0] ) bData = 1;
+        memcpy(pOut, a1, n1);
+        pOut += n1;
+      }else if( a2[0]!=0xFF && a1[0] ){
+        bData = 1;
+        memcpy(pOut, a2, n2);
+        pOut += n2;
+      }else{
+        *pOut++ = '\0';
+      }
+      a1 += n1;
+      a2 += n2;
+    }
+    if( bData ){
+      a2 = aChange;
+      for(i=0; i<pIter->nCol; i++){
+        int n1 = sessionSerialLen(a1);
+        int n2 = sessionSerialLen(a2);
+        if( pIter->abPK[i] || a2[0]!=0xFF ){
+          memcpy(pOut, a1, n1);
+          pOut += n1;
+        }else{
+          *pOut++ = '\0';
+        }
+        a1 += n1;
+        a2 += n2;
+      }
+      pBuf->nBuf = (pOut - pBuf->aBuf);
+    }
+  }
+}
+
+/*
+** pIter is configured to iterate through a changeset. This function rebases
+** that changeset according to the current configuration of the rebaser
+** object passed as the first argument. If no error occurs and argument xOutput
+** is not NULL, then the changeset is returned to the caller by invoking
+** xOutput zero or more times and SQLITE_OK returned. Or, if xOutput is NULL,
+** then (*ppOut) is set to point to a buffer containing the rebased changeset
+** before this function returns. In this case (*pnOut) is set to the size of
+** the buffer in bytes.  It is the responsibility of the caller to eventually
+** free the (*ppOut) buffer using sqlite3_free().
+**
+** If an error occurs, an SQLite error code is returned. If ppOut and
+** pnOut are not NULL, then the two output parameters are set to 0 before
+** returning.
+*/
+static int sessionRebase(
+  sqlite3_rebaser *p,             /* Rebaser hash table */
+  sqlite3_changeset_iter *pIter,  /* Input data */
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut,                     /* Context for xOutput callback */
+  int *pnOut,                     /* OUT: Number of bytes in output changeset */
+  void **ppOut                    /* OUT: Inverse of pChangeset */
+){
+  int rc = SQLITE_OK;
+  u8 *aRec = 0;
+  int nRec = 0;
+  int bNew = 0;
+  SessionTable *pTab = 0;
+  SessionBuffer sOut = {0,0,0};
+
+  while( SQLITE_ROW==sessionChangesetNext(pIter, &aRec, &nRec, &bNew) ){
+    SessionChange *pChange = 0;
+    int bDone = 0;
+
+    if( bNew ){
+      const char *zTab = pIter->zTab;
+      for(pTab=p->grp.pList; pTab; pTab=pTab->pNext){
+        if( 0==sqlite3_stricmp(pTab->zName, zTab) ) break;
+      }
+      bNew = 0;
+
+      /* A patchset may not be rebased */
+      if( pIter->bPatchset ){
+        rc = SQLITE_ERROR;
+      }
+
+      /* Append a table header to the output for this new table */
+      sessionAppendByte(&sOut, pIter->bPatchset ? 'P' : 'T', &rc);
+      sessionAppendVarint(&sOut, pIter->nCol, &rc);
+      sessionAppendBlob(&sOut, pIter->abPK, pIter->nCol, &rc);
+      sessionAppendBlob(&sOut,(u8*)pIter->zTab,(int)strlen(pIter->zTab)+1,&rc);
+    }
+
+    if( pTab && rc==SQLITE_OK ){
+      int iHash = sessionChangeHash(pTab, 0, aRec, pTab->nChange);
+
+      for(pChange=pTab->apChange[iHash]; pChange; pChange=pChange->pNext){
+        if( sessionChangeEqual(pTab, 0, aRec, 0, pChange->aRecord) ){
+          break;
+        }
+      }
+    }
+
+    if( pChange ){
+      assert( pChange->op==SQLITE_DELETE || pChange->op==SQLITE_INSERT );
+      switch( pIter->op ){
+        case SQLITE_INSERT:
+          if( pChange->op==SQLITE_INSERT ){
+            bDone = 1;
+            if( pChange->bIndirect==0 ){
+              sessionAppendByte(&sOut, SQLITE_UPDATE, &rc);
+              sessionAppendByte(&sOut, pIter->bIndirect, &rc);
+              sessionAppendBlob(&sOut, pChange->aRecord, pChange->nRecord, &rc);
+              sessionAppendBlob(&sOut, aRec, nRec, &rc);
+            }
+          }
+          break;
+
+        case SQLITE_UPDATE:
+          bDone = 1;
+          if( pChange->op==SQLITE_DELETE ){
+            if( pChange->bIndirect==0 ){
+              u8 *pCsr = aRec;
+              sessionSkipRecord(&pCsr, pIter->nCol);
+              sessionAppendByte(&sOut, SQLITE_INSERT, &rc);
+              sessionAppendByte(&sOut, pIter->bIndirect, &rc);
+              sessionAppendRecordMerge(&sOut, pIter->nCol,
+                  pCsr, nRec-(pCsr-aRec),
+                  pChange->aRecord, pChange->nRecord, &rc
+              );
+            }
+          }else{
+            sessionAppendPartialUpdate(&sOut, pIter,
+                aRec, nRec, pChange->aRecord, pChange->nRecord, &rc
+            );
+          }
+          break;
+
+        default:
+          assert( pIter->op==SQLITE_DELETE );
+          bDone = 1;
+          if( pChange->op==SQLITE_INSERT ){
+            sessionAppendByte(&sOut, SQLITE_DELETE, &rc);
+            sessionAppendByte(&sOut, pIter->bIndirect, &rc);
+            sessionAppendRecordMerge(&sOut, pIter->nCol,
+                pChange->aRecord, pChange->nRecord, aRec, nRec, &rc
+            );
+          }
+          break;
+      }
+    }
+
+    if( bDone==0 ){
+      sessionAppendByte(&sOut, pIter->op, &rc);
+      sessionAppendByte(&sOut, pIter->bIndirect, &rc);
+      sessionAppendBlob(&sOut, aRec, nRec, &rc);
+    }
+    if( rc==SQLITE_OK && xOutput && sOut.nBuf>sessions_strm_chunk_size ){
+      rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
+      sOut.nBuf = 0;
+    }
+    if( rc ) break;
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(sOut.aBuf);
+    memset(&sOut, 0, sizeof(sOut));
+  }
+
+  if( rc==SQLITE_OK ){
+    if( xOutput ){
+      if( sOut.nBuf>0 ){
+        rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
+      }
+    }else if( ppOut ){
+      *ppOut = (void*)sOut.aBuf;
+      *pnOut = sOut.nBuf;
+      sOut.aBuf = 0;
+    }
+  }
+  sqlite3_free(sOut.aBuf);
+  return rc;
+}
+
+/*
+** Create a new rebaser object.
+*/
+SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew){
+  int rc = SQLITE_OK;
+  sqlite3_rebaser *pNew;
+
+  pNew = sqlite3_malloc(sizeof(sqlite3_rebaser));
+  if( pNew==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    memset(pNew, 0, sizeof(sqlite3_rebaser));
+  }
+  *ppNew = pNew;
+  return rc;
+}
+
+/*
+** Call this one or more times to configure a rebaser.
+*/
+SQLITE_API int sqlite3rebaser_configure(
+  sqlite3_rebaser *p,
+  int nRebase, const void *pRebase
+){
+  sqlite3_changeset_iter *pIter = 0;   /* Iterator opened on pData/nData */
+  int rc;                              /* Return code */
+  rc = sqlite3changeset_start(&pIter, nRebase, (void*)pRebase);
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetToHash(pIter, &p->grp, 1);
+  }
+  sqlite3changeset_finalize(pIter);
+  return rc;
+}
+
+/*
+** Rebase a changeset according to current rebaser configuration
+*/
+SQLITE_API int sqlite3rebaser_rebase(
+  sqlite3_rebaser *p,
+  int nIn, const void *pIn,
+  int *pnOut, void **ppOut
+){
+  sqlite3_changeset_iter *pIter = 0;   /* Iterator to skip through input */
+  int rc = sqlite3changeset_start(&pIter, nIn, (void*)pIn);
+
+  if( rc==SQLITE_OK ){
+    rc = sessionRebase(p, pIter, 0, 0, pnOut, ppOut);
+    sqlite3changeset_finalize(pIter);
+  }
+
+  return rc;
+}
+
+/*
+** Rebase a changeset according to current rebaser configuration
+*/
+SQLITE_API int sqlite3rebaser_rebase_strm(
+  sqlite3_rebaser *p,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  sqlite3_changeset_iter *pIter = 0;   /* Iterator to skip through input */
+  int rc = sqlite3changeset_start_strm(&pIter, xInput, pIn);
+
+  if( rc==SQLITE_OK ){
+    rc = sessionRebase(p, pIter, xOutput, pOut, 0, 0);
+    sqlite3changeset_finalize(pIter);
+  }
+
+  return rc;
+}
+
+/*
+** Destroy a rebaser object
+*/
+SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p){
+  if( p ){
+    sessionDeleteTable(0, p->grp.pList);
+    sqlite3_free(p->grp.rec.aBuf);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Global configuration
+*/
+SQLITE_API int sqlite3session_config(int op, void *pArg){
+  int rc = SQLITE_OK;
+  switch( op ){
+    case SQLITE_SESSION_CONFIG_STRMSIZE: {
+      int *pInt = (int*)pArg;
+      if( *pInt>0 ){
+        sessions_strm_chunk_size = *pInt;
+      }
+      *pInt = sessions_strm_chunk_size;
+      break;
+    }
+    default:
+      rc = SQLITE_MISUSE;
+      break;
+  }
+  return rc;
+}
+
+#endif /* SQLITE_ENABLE_SESSION && SQLITE_ENABLE_PREUPDATE_HOOK */
+
+/************** End of sqlite3session.c **************************************/
+/************** Begin file fts5.c ********************************************/
+
+/*
+** This, the "fts5.c" source file, is a composite file that is itself
+** assembled from the following files:
+**
+**    fts5.h
+**    fts5Int.h
+**    fts5parse.h          <--- Generated from fts5parse.y by Lemon
+**    fts5parse.c          <--- Generated from fts5parse.y by Lemon
+**    fts5_aux.c
+**    fts5_buffer.c
+**    fts5_config.c
+**    fts5_expr.c
+**    fts5_hash.c
+**    fts5_index.c
+**    fts5_main.c
+**    fts5_storage.c
+**    fts5_tokenize.c
+**    fts5_unicode2.c
+**    fts5_varint.c
+**    fts5_vocab.c
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS5)
+
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+#if defined(NDEBUG) && defined(SQLITE_DEBUG)
+# undef NDEBUG
+#endif
+
+#ifdef HAVE_STDINT_H
+/* #include <stdint.h> */
+#endif
+#ifdef HAVE_INTTYPES_H
+/* #include <inttypes.h> */
+#endif
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Interfaces to extend FTS5. Using the interfaces defined in this file,
+** FTS5 may be extended with:
+**
+**     * custom tokenizers, and
+**     * custom auxiliary functions.
+*/
+
+
+#ifndef _FTS5_H
+#define _FTS5_H
+
+/* #include "sqlite3.h" */
+
+#if 0
+extern "C" {
+#endif
+
+/*************************************************************************
+** CUSTOM AUXILIARY FUNCTIONS
+**
+** Virtual table implementations may overload SQL functions by implementing
+** the sqlite3_module.xFindFunction() method.
+*/
+
+typedef struct Fts5ExtensionApi Fts5ExtensionApi;
+typedef struct Fts5Context Fts5Context;
+typedef struct Fts5PhraseIter Fts5PhraseIter;
+
+typedef void (*fts5_extension_function)(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+);
+
+struct Fts5PhraseIter {
+  const unsigned char *a;
+  const unsigned char *b;
+};
+
+/*
+** EXTENSION API FUNCTIONS
+**
+** xUserData(pFts):
+**   Return a copy of the pUserData pointer passed to the xCreateFunction()
+**   API when the extension function was registered.
+**
+** xColumnTotalSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the FTS5 table. Or, if iCol is
+**   non-negative but less than the number of columns in the table, return
+**   the total number of tokens in column iCol, considering all rows in
+**   the FTS5 table.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+** xColumnCount(pFts):
+**   Return the number of columns in the table.
+**
+** xColumnSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the current row. Or, if iCol is
+**   non-negative but less than the number of columns in the table, set
+**   *pnToken to the number of tokens in column iCol of the current row.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+**   This function may be quite inefficient if used with an FTS5 table
+**   created with the "columnsize=0" option.
+**
+** xColumnText:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the text of column iCol of
+**   the current document. If successful, (*pz) is set to point to a buffer
+**   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
+**   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
+**   if an error occurs, an SQLite error code is returned and the final values
+**   of (*pz) and (*pn) are undefined.
+**
+** xPhraseCount:
+**   Returns the number of phrases in the current query expression.
+**
+** xPhraseSize:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of phrases in the current query, as returned by xPhraseCount,
+**   0 is returned. Otherwise, this function returns the number of tokens in
+**   phrase iPhrase of the query. Phrases are numbered starting from zero.
+**
+** xInstCount:
+**   Set *pnInst to the total number of occurrences of all phrases within
+**   the query within the current row. Return SQLITE_OK if successful, or
+**   an error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always returns 0.
+**
+** xInst:
+**   Query for the details of phrase match iIdx within the current row.
+**   Phrase matches are numbered starting from zero, so the iIdx argument
+**   should be greater than or equal to zero and smaller than the value
+**   output by xInstCount(). If iIdx is less than zero or greater than
+**   or equal to the value returned by xInstCount(), SQLITE_RANGE is returned.
+**
+**   Otherwise, output parameter *piPhrase is set to the phrase number, *piCol
+**   to the column in which it occurs and *piOff the token offset of the
+**   first token of the phrase. SQLITE_OK is returned if successful, or an
+**   error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xRowid:
+**   Returns the rowid of the current row.
+**
+** xTokenize:
+**   Tokenize text using the tokenizer belonging to the FTS5 table.
+**
+** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
+**   This API function is used to query the FTS table for phrase iPhrase
+**   of the current query. Specifically, a query equivalent to:
+**
+**       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
+**
+**   with $p set to a phrase equivalent to the phrase iPhrase of the
+**   current query is executed. Any column filter that applies to
+**   phrase iPhrase of the current query is included in $p. For each
+**   row visited, the callback function passed as the fourth argument
+**   is invoked. The context and API objects passed to the callback
+**   function may be used to access the properties of each matched row.
+**   Invoking Api.xUserData() returns a copy of the pointer passed as
+**   the third argument to pUserData.
+**
+**   If parameter iPhrase is less than zero, or greater than or equal to
+**   the number of phrases in the query, as returned by xPhraseCount(),
+**   this function returns SQLITE_RANGE.
+**
+**   If the callback function returns any value other than SQLITE_OK, the
+**   query is abandoned and the xQueryPhrase function returns immediately.
+**   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
+**   Otherwise, the error code is propagated upwards.
+**
+**   If the query runs to completion without incident, SQLITE_OK is returned.
+**   Or, if some error occurs before the query completes or is aborted by
+**   the callback, an SQLite error code is returned.
+**
+**
+** xSetAuxdata(pFts5, pAux, xDelete)
+**
+**   Save the pointer passed as the second argument as the extension function's
+**   "auxiliary data". The pointer may then be retrieved by the current or any
+**   future invocation of the same fts5 extension function made as part of
+**   the same MATCH query using the xGetAuxdata() API.
+**
+**   Each extension function is allocated a single auxiliary data slot for
+**   each FTS query (MATCH expression). If the extension function is invoked
+**   more than once for a single FTS query, then all invocations share a
+**   single auxiliary data context.
+**
+**   If there is already an auxiliary data pointer when this function is
+**   invoked, then it is replaced by the new pointer. If an xDelete callback
+**   was specified along with the original pointer, it is invoked at this
+**   point.
+**
+**   The xDelete callback, if one is specified, is also invoked on the
+**   auxiliary data pointer after the FTS5 query has finished.
+**
+**   If an error (e.g. an OOM condition) occurs within this function,
+**   the auxiliary data is set to NULL and an error code returned. If the
+**   xDelete parameter was not NULL, it is invoked on the auxiliary data
+**   pointer before returning.
+**
+**
+** xGetAuxdata(pFts5, bClear)
+**
+**   Returns the current auxiliary data pointer for the fts5 extension
+**   function. See the xSetAuxdata() method for details.
+**
+**   If the bClear argument is non-zero, then the auxiliary data is cleared
+**   (set to NULL) before this function returns. In this case the xDelete,
+**   if any, is not invoked.
+**
+**
+** xRowCount(pFts5, pnRow)
+**
+**   This function is used to retrieve the total number of rows in the table.
+**   In other words, the same value that would be returned by:
+**
+**        SELECT count(*) FROM ftstable;
+**
+** xPhraseFirst()
+**   This function is used, along with type Fts5PhraseIter and the xPhraseNext
+**   method, to iterate through all instances of a single query phrase within
+**   the current row. This is the same information as is accessible via the
+**   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
+**   to use, this API may be faster under some circumstances. To iterate
+**   through instances of phrase iPhrase, use the following code:
+**
+**       Fts5PhraseIter iter;
+**       int iCol, iOff;
+**       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
+**           iCol>=0;
+**           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
+**       ){
+**         // An instance of phrase iPhrase at offset iOff of column iCol
+**       }
+**
+**   The Fts5PhraseIter structure is defined above. Applications should not
+**   modify this structure directly - it should only be used as shown above
+**   with the xPhraseFirst() and xPhraseNext() API methods (and by
+**   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always iterates
+**   through an empty set (all calls to xPhraseFirst() set iCol to -1).
+**
+**   In all cases, matches are visited in (column ASC, offset ASC) order.
+**   i.e. all those in column 0, sorted by offset, followed by those in
+**   column 1, etc.
+**
+** xPhraseNext()
+**   See xPhraseFirst above.
+**
+** xPhraseFirstColumn()
+**   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
+**   and xPhraseNext() APIs described above. The difference is that instead
+**   of iterating through all instances of a phrase in the current row, these
+**   APIs are used to iterate through the set of columns in the current row
+**   that contain one or more instances of a specified phrase. For example:
+**
+**       Fts5PhraseIter iter;
+**       int iCol;
+**       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
+**           iCol>=0;
+**           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
+**       ){
+**         // Column iCol contains at least one instance of phrase iPhrase
+**       }
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" option. If the FTS5 table is created with either
+**   "detail=none" "content=" option (i.e. if it is a contentless table),
+**   then this API always iterates through an empty set (all calls to
+**   xPhraseFirstColumn() set iCol to -1).
+**
+**   The information accessed using this API and its companion
+**   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
+**   (or xInst/xInstCount). The chief advantage of this API is that it is
+**   significantly more efficient than those alternatives when used with
+**   "detail=column" tables.
+**
+** xPhraseNextColumn()
+**   See xPhraseFirstColumn above.
+**
+** xQueryToken(pFts5, iPhrase, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase iPhrase of the current
+**   query. Before returning, output parameter *ppToken is set to point
+**   to a buffer containing the requested token, and *pnToken to the
+**   size of this buffer in bytes.
+**
+**   If iPhrase or iToken are less than zero, or if iPhrase is greater than
+**   or equal to the number of phrases in the query as reported by
+**   xPhraseCount(), or if iToken is equal to or greater than the number of
+**   tokens in the phrase, SQLITE_RANGE is returned and *ppToken and *pnToken
+     are both zeroed.
+**
+**   The output text is not a copy of the query text that specified the
+**   token. It is the output of the tokenizer module. For tokendata=1
+**   tables, this includes any embedded 0x00 and trailing data.
+**
+** xInstToken(pFts5, iIdx, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase hit iIdx within the
+**   current row. If iIdx is less than zero or greater than or equal to the
+**   value returned by xInstCount(), SQLITE_RANGE is returned.  Otherwise,
+**   output variable (*ppToken) is set to point to a buffer containing the
+**   matching document token, and (*pnToken) to the size of that buffer in
+**   bytes.
+**
+**   The output text is not a copy of the document text that was tokenized.
+**   It is the output of the tokenizer module. For tokendata=1 tables, this
+**   includes any embedded 0x00 and trailing data.
+**
+**   This API may be slow in some cases if the token identified by parameters
+**   iIdx and iToken matched a prefix token in the query. In most cases, the
+**   first call to this API for each prefix token in the query is forced
+**   to scan the portion of the full-text index that matches the prefix
+**   token to collect the extra data required by this API. If the prefix
+**   token matches a large number of token instances in the document set,
+**   this may be a performance problem.
+**
+**   If the user knows in advance that a query may use this API for a
+**   prefix token, FTS5 may be configured to collect all required data as part
+**   of the initial querying of the full-text index, avoiding the second scan
+**   entirely. This also causes prefix queries that do not use this API to
+**   run more slowly and use more memory. FTS5 may be configured in this way
+**   either on a per-table basis using the [FTS5 insttoken | 'insttoken']
+**   option, or on a per-query basis using the
+**   [fts5_insttoken | fts5_insttoken()] user function.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xColumnLocale(pFts5, iIdx, pzLocale, pnLocale)
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the locale associated
+**   with column iCol of the current row. Usually, there is no associated
+**   locale, and output parameters (*pzLocale) and (*pnLocale) are set
+**   to NULL and 0, respectively. However, if the fts5_locale() function
+**   was used to associate a locale with the value when it was inserted
+**   into the fts5 table, then (*pzLocale) is set to point to a nul-terminated
+**   buffer containing the name of the locale in utf-8 encoding. (*pnLocale)
+**   is set to the size in bytes of the buffer, not including the
+**   nul-terminator.
+**
+**   If successful, SQLITE_OK is returned. Or, if an error occurs, an
+**   SQLite error code is returned. The final value of the output parameters
+**   is undefined in this case.
+**
+** xTokenize_v2:
+**   Tokenize text using the tokenizer belonging to the FTS5 table. This
+**   API is the same as the xTokenize() API, except that it allows a tokenizer
+**   locale to be specified.
+*/
+struct Fts5ExtensionApi {
+  int iVersion;                   /* Currently always set to 4 */
+
+  void *(*xUserData)(Fts5Context*);
+
+  int (*xColumnCount)(Fts5Context*);
+  int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
+  int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
+
+  int (*xTokenize)(Fts5Context*,
+    const char *pText, int nText, /* Text to tokenize */
+    void *pCtx,                   /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+
+  int (*xPhraseCount)(Fts5Context*);
+  int (*xPhraseSize)(Fts5Context*, int iPhrase);
+
+  int (*xInstCount)(Fts5Context*, int *pnInst);
+  int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
+
+  sqlite3_int64 (*xRowid)(Fts5Context*);
+  int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
+
+  int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
+    int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
+  );
+  int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
+  void *(*xGetAuxdata)(Fts5Context*, int bClear);
+
+  int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
+  void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
+
+  int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
+  void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
+
+  /* Below this point are iVersion>=3 only */
+  int (*xQueryToken)(Fts5Context*,
+      int iPhrase, int iToken,
+      const char **ppToken, int *pnToken
+  );
+  int (*xInstToken)(Fts5Context*, int iIdx, int iToken, const char**, int*);
+
+  /* Below this point are iVersion>=4 only */
+  int (*xColumnLocale)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xTokenize_v2)(Fts5Context*,
+    const char *pText, int nText,      /* Text to tokenize */
+    const char *pLocale, int nLocale,  /* Locale to pass to tokenizer */
+    void *pCtx,                        /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+};
+
+/*
+** CUSTOM AUXILIARY FUNCTIONS
+*************************************************************************/
+
+/*************************************************************************
+** CUSTOM TOKENIZERS
+**
+** Applications may also register custom tokenizer types. A tokenizer
+** is registered by providing fts5 with a populated instance of the
+** following structure. All structure methods must be defined, setting
+** any member of the fts5_tokenizer struct to NULL leads to undefined
+** behaviour. The structure methods are expected to function as follows:
+**
+** xCreate:
+**   This function is used to allocate and initialize a tokenizer instance.
+**   A tokenizer instance is required to actually tokenize text.
+**
+**   The first argument passed to this function is a copy of the (void*)
+**   pointer provided by the application when the fts5_tokenizer_v2 object
+**   was registered with FTS5 (the third argument to xCreateTokenizer()).
+**   The second and third arguments are an array of nul-terminated strings
+**   containing the tokenizer arguments, if any, specified following the
+**   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
+**   to create the FTS5 table.
+**
+**   The final argument is an output variable. If successful, (*ppOut)
+**   should be set to point to the new tokenizer handle and SQLITE_OK
+**   returned. If an error occurs, some value other than SQLITE_OK should
+**   be returned. In this case, fts5 assumes that the final value of *ppOut
+**   is undefined.
+**
+** xDelete:
+**   This function is invoked to delete a tokenizer handle previously
+**   allocated using xCreate(). Fts5 guarantees that this function will
+**   be invoked exactly once for each successful call to xCreate().
+**
+** xTokenize:
+**   This function is expected to tokenize the nText byte string indicated
+**   by argument pText. pText may or may not be nul-terminated. The first
+**   argument passed to this function is a pointer to an Fts5Tokenizer object
+**   returned by an earlier call to xCreate().
+**
+**   The third argument indicates the reason that FTS5 is requesting
+**   tokenization of the supplied text. This is always one of the following
+**   four values:
+**
+**   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
+**            or removed from the FTS table. The tokenizer is being invoked to
+**            determine the set of tokens to add to (or delete from) the
+**            FTS index.
+**
+**       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
+**            against the FTS index. The tokenizer is being called to tokenize
+**            a bareword or quoted string specified as part of the query.
+**
+**       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
+**            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
+**            followed by a "*" character, indicating that the last token
+**            returned by the tokenizer will be treated as a token prefix.
+**
+**       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
+**            satisfy an fts5_api.xTokenize() request made by an auxiliary
+**            function. Or an fts5_api.xColumnSize() request made by the same
+**            on a columnsize=0 database.
+**   </ul>
+**
+**   The sixth and seventh arguments passed to xTokenize() - pLocale and
+**   nLocale - are a pointer to a buffer containing the locale to use for
+**   tokenization (e.g. "en_US") and its size in bytes, respectively. The
+**   pLocale buffer is not nul-terminated. pLocale may be passed NULL (in
+**   which case nLocale is always 0) to indicate that the tokenizer should
+**   use its default locale.
+**
+**   For each token in the input string, the supplied callback xToken() must
+**   be invoked. The first argument to it should be a copy of the pointer
+**   passed as the second argument to xTokenize(). The third and fourth
+**   arguments are a pointer to a buffer containing the token text, and the
+**   size of the token in bytes. The 4th and 5th arguments are the byte offsets
+**   of the first byte of and first byte immediately following the text from
+**   which the token is derived within the input.
+**
+**   The second argument passed to the xToken() callback ("tflags") should
+**   normally be set to 0. The exception is if the tokenizer supports
+**   synonyms. In this case see the discussion below for details.
+**
+**   FTS5 assumes the xToken() callback is invoked for each token in the
+**   order that they occur within the input text.
+**
+**   If an xToken() callback returns any value other than SQLITE_OK, then
+**   the tokenization should be abandoned and the xTokenize() method should
+**   immediately return a copy of the xToken() return value. Or, if the
+**   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
+**   if an error occurs with the xTokenize() implementation itself, it
+**   may abandon the tokenization and return any error code other than
+**   SQLITE_OK or SQLITE_DONE.
+**
+**   If the tokenizer is registered using an fts5_tokenizer_v2 object,
+**   then the xTokenize() method has two additional arguments - pLocale
+**   and nLocale. These specify the locale that the tokenizer should use
+**   for the current request. If pLocale and nLocale are both 0, then the
+**   tokenizer should use its default locale. Otherwise, pLocale points to
+**   an nLocale byte buffer containing the name of the locale to use as utf-8
+**   text. pLocale is not nul-terminated.
+**
+** FTS5_TOKENIZER
+**
+** There is also an fts5_tokenizer object. This is an older, deprecated,
+** version of fts5_tokenizer_v2. It is similar except that:
+**
+**  <ul>
+**    <li> There is no "iVersion" field, and
+**    <li> The xTokenize() method does not take a locale argument.
+**  </ul>
+**
+** Legacy fts5_tokenizer tokenizers must be registered using the
+** legacy xCreateTokenizer() function, instead of xCreateTokenizer_v2().
+**
+** Tokenizer implementations registered using either API may be retrieved
+** using both xFindTokenizer() and xFindTokenizer_v2().
+**
+** SYNONYM SUPPORT
+**
+**   Custom tokenizers may also support synonyms. Consider a case in which a
+**   user wishes to query for a phrase such as "first place". Using the
+**   built-in tokenizers, the FTS5 query 'first + place' will match instances
+**   of "first place" within the document set, but not alternative forms
+**   such as "1st place". In some applications, it would be better to match
+**   all instances of "first place" or "1st place" regardless of which form
+**   the user specified in the MATCH query text.
+**
+**   There are several ways to approach this in FTS5:
+**
+**   <ol><li> By mapping all synonyms to a single token. In this case, using
+**            the above example, this means that the tokenizer returns the
+**            same token for inputs "first" and "1st". Say that token is in
+**            fact "first", so that when the user inserts the document "I won
+**            1st place" entries are added to the index for tokens "i", "won",
+**            "first" and "place". If the user then queries for '1st + place',
+**            the tokenizer substitutes "first" for "1st" and the query works
+**            as expected.
+**
+**       <li> By querying the index for all synonyms of each query term
+**            separately. In this case, when tokenizing query text, the
+**            tokenizer may provide multiple synonyms for a single term
+**            within the document. FTS5 then queries the index for each
+**            synonym individually. For example, faced with the query:
+**
+**   <codeblock>
+**     ... MATCH 'first place'</codeblock>
+**
+**            the tokenizer offers both "1st" and "first" as synonyms for the
+**            first token in the MATCH query and FTS5 effectively runs a query
+**            similar to:
+**
+**   <codeblock>
+**     ... MATCH '(first OR 1st) place'</codeblock>
+**
+**            except that, for the purposes of auxiliary functions, the query
+**            still appears to contain just two phrases - "(first OR 1st)"
+**            being treated as a single phrase.
+**
+**       <li> By adding multiple synonyms for a single term to the FTS index.
+**            Using this method, when tokenizing document text, the tokenizer
+**            provides multiple synonyms for each token. So that when a
+**            document such as "I won first place" is tokenized, entries are
+**            added to the FTS index for "i", "won", "first", "1st" and
+**            "place".
+**
+**            This way, even if the tokenizer does not provide synonyms
+**            when tokenizing query text (it should not - to do so would be
+**            inefficient), it doesn't matter if the user queries for
+**            'first + place' or '1st + place', as there are entries in the
+**            FTS index corresponding to both forms of the first token.
+**   </ol>
+**
+**   Whether it is parsing document or query text, any call to xToken that
+**   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
+**   is considered to supply a synonym for the previous token. For example,
+**   when parsing the document "I won first place", a tokenizer that supports
+**   synonyms would call xToken() 5 times, as follows:
+**
+**   <codeblock>
+**       xToken(pCtx, 0, "i",                      1,  0,  1);
+**       xToken(pCtx, 0, "won",                    3,  2,  5);
+**       xToken(pCtx, 0, "first",                  5,  6, 11);
+**       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
+**       xToken(pCtx, 0, "place",                  5, 12, 17);
+**</codeblock>
+**
+**   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
+**   xToken() is called. Multiple synonyms may be specified for a single token
+**   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
+**   There is no limit to the number of synonyms that may be provided for a
+**   single token.
+**
+**   In many cases, method (1) above is the best approach. It does not add
+**   extra data to the FTS index or require FTS5 to query for multiple terms,
+**   so it is efficient in terms of disk space and query speed. However, it
+**   does not support prefix queries very well. If, as suggested above, the
+**   token "first" is substituted for "1st" by the tokenizer, then the query:
+**
+**   <codeblock>
+**     ... MATCH '1s*'</codeblock>
+**
+**   will not match documents that contain the token "1st" (as the tokenizer
+**   will probably not map "1s" to any prefix of "first").
+**
+**   For full prefix support, method (3) may be preferred. In this case,
+**   because the index contains entries for both "first" and "1st", prefix
+**   queries such as 'fi*' or '1s*' will match correctly. However, because
+**   extra entries are added to the FTS index, this method uses more space
+**   within the database.
+**
+**   Method (2) offers a midpoint between (1) and (3). Using this method,
+**   a query such as '1s*' will match documents that contain the literal
+**   token "1st", but not "first" (assuming the tokenizer is not able to
+**   provide synonyms for prefixes). However, a non-prefix query like '1st'
+**   will match against "1st" and "first". This method does not require
+**   extra disk space, as no extra entries are added to the FTS index.
+**   On the other hand, it may require more CPU cycles to run MATCH queries,
+**   as separate queries of the FTS index are required for each synonym.
+**
+**   When using methods (2) or (3), it is important that the tokenizer only
+**   provide synonyms when tokenizing document text (method (3)) or query
+**   text (method (2)), not both. Doing so will not cause any errors, but is
+**   inefficient.
+*/
+typedef struct Fts5Tokenizer Fts5Tokenizer;
+typedef struct fts5_tokenizer_v2 fts5_tokenizer_v2;
+struct fts5_tokenizer_v2 {
+  int iVersion;             /* Currently always 2 */
+
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      const char *pLocale, int nLocale,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+/*
+** New code should use the fts5_tokenizer_v2 type to define tokenizer
+** implementations. The following type is included for legacy applications
+** that still use it.
+*/
+typedef struct fts5_tokenizer fts5_tokenizer;
+struct fts5_tokenizer {
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+
+/* Flags that may be passed as the third argument to xTokenize() */
+#define FTS5_TOKENIZE_QUERY     0x0001
+#define FTS5_TOKENIZE_PREFIX    0x0002
+#define FTS5_TOKENIZE_DOCUMENT  0x0004
+#define FTS5_TOKENIZE_AUX       0x0008
+
+/* Flags that may be passed by the tokenizer implementation back to FTS5
+** as the third argument to the supplied xToken callback. */
+#define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
+
+/*
+** END OF CUSTOM TOKENIZERS
+*************************************************************************/
+
+/*************************************************************************
+** FTS5 EXTENSION REGISTRATION API
+*/
+typedef struct fts5_api fts5_api;
+struct fts5_api {
+  int iVersion;                   /* Currently always set to 3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer *pTokenizer
+  );
+
+  /* Create a new auxiliary function */
+  int (*xCreateFunction)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_extension_function xFunction,
+    void (*xDestroy)(void*)
+  );
+
+  /* APIs below this point are only available if iVersion>=3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer_v2 *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer_v2 **ppTokenizer
+  );
+};
+
+/*
+** END OF REGISTRATION API
+*************************************************************************/
+
+#if 0
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* _FTS5_H */
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+#ifndef _FTS5INT_H
+#define _FTS5INT_H
+
+/* #include "fts5.h" */
+/* #include "sqlite3ext.h" */
+SQLITE_EXTENSION_INIT1
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+#ifndef SQLITE_AMALGAMATION
+
+typedef unsigned char  u8;
+typedef unsigned int   u32;
+typedef unsigned short u16;
+typedef short i16;
+typedef sqlite3_int64 i64;
+typedef sqlite3_uint64 u64;
+
+#ifndef ArraySize
+# define ArraySize(x) ((int)(sizeof(x) / sizeof(x[0])))
+#endif
+
+#define testcase(x)
+
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
+# define SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS 1
+#endif
+#if defined(SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS)
+# define ALWAYS(X)      (1)
+# define NEVER(X)       (0)
+#elif !defined(NDEBUG)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
+#else
+# define ALWAYS(X)      (X)
+# define NEVER(X)       (X)
+#endif
+
+#define MIN(x,y) (((x) < (y)) ? (x) : (y))
+#define MAX(x,y) (((x) > (y)) ? (x) : (y))
+
+/*
+** Constants for the largest and smallest possible 64-bit signed integers.
+*/
+# define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
+# define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
+
+/* The uptr type is an unsigned integer large enough to hold a pointer
+*/
+#if defined(HAVE_STDINT_H)
+  typedef uintptr_t uptr;
+#elif SQLITE_PTRSIZE==4
+  typedef u32 uptr;
+#else
+  typedef u64 uptr;
+#endif
+
+#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&3)==0)
+#else
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&7)==0)
+#endif
+
+#endif
+
+/* Truncate very long tokens to this many bytes. Hard limit is
+** (65536-1-1-4-9)==65521 bytes. The limiting factor is the 16-bit offset
+** field that occurs at the start of each leaf page (see fts5_index.c). */
+#define FTS5_MAX_TOKEN_SIZE 32768
+
+/*
+** Maximum number of prefix indexes on single FTS5 table. This must be
+** less than 32. If it is set to anything large than that, an #error
+** directive in fts5_index.c will cause the build to fail.
+*/
+#define FTS5_MAX_PREFIX_INDEXES 31
+
+/*
+** Maximum segments permitted in a single index
+*/
+#define FTS5_MAX_SEGMENT 2000
+
+#define FTS5_DEFAULT_NEARDIST 10
+#define FTS5_DEFAULT_RANK     "bm25"
+
+/* Name of rank and rowid columns */
+#define FTS5_RANK_NAME "rank"
+#define FTS5_ROWID_NAME "rowid"
+
+#ifdef SQLITE_DEBUG
+# define FTS5_CORRUPT sqlite3Fts5Corrupt()
+static int sqlite3Fts5Corrupt(void);
+#else
+# define FTS5_CORRUPT SQLITE_CORRUPT_VTAB
+#endif
+
+/*
+** The assert_nc() macro is similar to the assert() macro, except that it
+** is used for assert() conditions that are true only if it can be
+** guranteed that the database is not corrupt.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_API extern int sqlite3_fts5_may_be_corrupt;
+# define assert_nc(x) assert(sqlite3_fts5_may_be_corrupt || (x))
+#else
+# define assert_nc(x) assert(x)
+#endif
+
+/*
+** A version of memcmp() that does not cause asan errors if one of the pointer
+** parameters is NULL and the number of bytes to compare is zero.
+*/
+#define fts5Memcmp(s1, s2, n) ((n)<=0 ? 0 : memcmp((s1), (s2), (n)))
+
+/* Mark a function parameter as unused, to suppress nuisance compiler
+** warnings. */
+#ifndef UNUSED_PARAM
+# define UNUSED_PARAM(X)  (void)(X)
+#endif
+
+#ifndef UNUSED_PARAM2
+# define UNUSED_PARAM2(X, Y)  (void)(X), (void)(Y)
+#endif
+
+typedef struct Fts5Global Fts5Global;
+typedef struct Fts5Colset Fts5Colset;
+
+/* If a NEAR() clump or phrase may only match a specific set of columns,
+** then an object of the following type is used to record the set of columns.
+** Each entry in the aiCol[] array is a column that may be matched.
+**
+** This object is used by fts5_expr.c and fts5_index.c.
+*/
+struct Fts5Colset {
+  int nCol;
+  int aiCol[1];
+};
+
+
+
+/**************************************************************************
+** Interface to code in fts5_config.c. fts5_config.c contains contains code
+** to parse the arguments passed to the CREATE VIRTUAL TABLE statement.
+*/
+
+typedef struct Fts5Config Fts5Config;
+typedef struct Fts5TokenizerConfig Fts5TokenizerConfig;
+
+struct Fts5TokenizerConfig {
+  Fts5Tokenizer *pTok;
+  fts5_tokenizer_v2 *pApi2;
+  fts5_tokenizer *pApi1;
+  const char **azArg;
+  int nArg;
+  int ePattern;                   /* FTS_PATTERN_XXX constant */
+  const char *pLocale;            /* Current locale to use */
+  int nLocale;                    /* Size of pLocale in bytes */
+};
+
+/*
+** An instance of the following structure encodes all information that can
+** be gleaned from the CREATE VIRTUAL TABLE statement.
+**
+** And all information loaded from the %_config table.
+**
+** nAutomerge:
+**   The minimum number of segments that an auto-merge operation should
+**   attempt to merge together. A value of 1 sets the object to use the
+**   compile time default. Zero disables auto-merge altogether.
+**
+** bContentlessDelete:
+**   True if the contentless_delete option was present in the CREATE
+**   VIRTUAL TABLE statement.
+**
+** zContent:
+**
+** zContentRowid:
+**   The value of the content_rowid= option, if one was specified. Or
+**   the string "rowid" otherwise. This text is not quoted - if it is
+**   used as part of an SQL statement it needs to be quoted appropriately.
+**
+** zContentExprlist:
+**
+** pzErrmsg:
+**   This exists in order to allow the fts5_index.c module to return a
+**   decent error message if it encounters a file-format version it does
+**   not understand.
+**
+** bColumnsize:
+**   True if the %_docsize table is created.
+**
+** bPrefixIndex:
+**   This is only used for debugging. If set to false, any prefix indexes
+**   are ignored. This value is configured using:
+**
+**       INSERT INTO tbl(tbl, rank) VALUES('prefix-index', $bPrefixIndex);
+**
+** bLocale:
+**   Set to true if locale=1 was specified when the table was created.
+*/
+struct Fts5Config {
+  sqlite3 *db;                    /* Database handle */
+  Fts5Global *pGlobal;            /* Global fts5 object for handle db */
+  char *zDb;                      /* Database holding FTS index (e.g. "main") */
+  char *zName;                    /* Name of FTS index */
+  int nCol;                       /* Number of columns */
+  char **azCol;                   /* Column names */
+  u8 *abUnindexed;                /* True for unindexed columns */
+  int nPrefix;                    /* Number of prefix indexes */
+  int *aPrefix;                   /* Sizes in bytes of nPrefix prefix indexes */
+  int eContent;                   /* An FTS5_CONTENT value */
+  int bContentlessDelete;         /* "contentless_delete=" option (dflt==0) */
+  int bContentlessUnindexed;      /* "contentless_unindexed=" option (dflt=0) */
+  char *zContent;                 /* content table */
+  char *zContentRowid;            /* "content_rowid=" option value */
+  int bColumnsize;                /* "columnsize=" option value (dflt==1) */
+  int bTokendata;                 /* "tokendata=" option value (dflt==0) */
+  int bLocale;                    /* "locale=" option value (dflt==0) */
+  int eDetail;                    /* FTS5_DETAIL_XXX value */
+  char *zContentExprlist;
+  Fts5TokenizerConfig t;
+  int bLock;                      /* True when table is preparing statement */
+
+
+  /* Values loaded from the %_config table */
+  int iVersion;                   /* fts5 file format 'version' */
+  int iCookie;                    /* Incremented when %_config is modified */
+  int pgsz;                       /* Approximate page size used in %_data */
+  int nAutomerge;                 /* 'automerge' setting */
+  int nCrisisMerge;               /* Maximum allowed segments per level */
+  int nUsermerge;                 /* 'usermerge' setting */
+  int nHashSize;                  /* Bytes of memory for in-memory hash */
+  char *zRank;                    /* Name of rank function */
+  char *zRankArgs;                /* Arguments to rank function */
+  int bSecureDelete;              /* 'secure-delete' */
+  int nDeleteMerge;               /* 'deletemerge' */
+  int bPrefixInsttoken;           /* 'prefix-insttoken' */
+
+  /* If non-NULL, points to sqlite3_vtab.base.zErrmsg. Often NULL. */
+  char **pzErrmsg;
+
+#ifdef SQLITE_DEBUG
+  int bPrefixIndex;               /* True to use prefix-indexes */
+#endif
+};
+
+/* Current expected value of %_config table 'version' field. And
+** the expected version if the 'secure-delete' option has ever been
+** set on the table.  */
+#define FTS5_CURRENT_VERSION               4
+#define FTS5_CURRENT_VERSION_SECUREDELETE  5
+
+#define FTS5_CONTENT_NORMAL    0
+#define FTS5_CONTENT_NONE      1
+#define FTS5_CONTENT_EXTERNAL  2
+#define FTS5_CONTENT_UNINDEXED 3
+
+#define FTS5_DETAIL_FULL      0
+#define FTS5_DETAIL_NONE      1
+#define FTS5_DETAIL_COLUMNS   2
+
+#define FTS5_PATTERN_NONE     0
+#define FTS5_PATTERN_LIKE     65  /* matches SQLITE_INDEX_CONSTRAINT_LIKE */
+#define FTS5_PATTERN_GLOB     66  /* matches SQLITE_INDEX_CONSTRAINT_GLOB */
+
+static int sqlite3Fts5ConfigParse(
+    Fts5Global*, sqlite3*, int, const char **, Fts5Config**, char**
+);
+static void sqlite3Fts5ConfigFree(Fts5Config*);
+
+static int sqlite3Fts5ConfigDeclareVtab(Fts5Config *pConfig);
+
+static int sqlite3Fts5Tokenize(
+  Fts5Config *pConfig,            /* FTS5 Configuration object */
+  int flags,                      /* FTS5_TOKENIZE_* flags */
+  const char *pText, int nText,   /* Text to tokenize */
+  void *pCtx,                     /* Context passed to xToken() */
+  int (*xToken)(void*, int, const char*, int, int, int)    /* Callback */
+);
+
+static void sqlite3Fts5Dequote(char *z);
+
+/* Load the contents of the %_config table */
+static int sqlite3Fts5ConfigLoad(Fts5Config*, int);
+
+/* Set the value of a single config attribute */
+static int sqlite3Fts5ConfigSetValue(Fts5Config*, const char*, sqlite3_value*, int*);
+
+static int sqlite3Fts5ConfigParseRank(const char*, char**, char**);
+
+static void sqlite3Fts5ConfigErrmsg(Fts5Config *pConfig, const char *zFmt, ...);
+
+/*
+** End of interface to code in fts5_config.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_buffer.c.
+*/
+
+/*
+** Buffer object for the incremental building of string data.
+*/
+typedef struct Fts5Buffer Fts5Buffer;
+struct Fts5Buffer {
+  u8 *p;
+  int n;
+  int nSpace;
+};
+
+static int sqlite3Fts5BufferSize(int*, Fts5Buffer*, u32);
+static void sqlite3Fts5BufferAppendVarint(int*, Fts5Buffer*, i64);
+static void sqlite3Fts5BufferAppendBlob(int*, Fts5Buffer*, u32, const u8*);
+static void sqlite3Fts5BufferAppendString(int *, Fts5Buffer*, const char*);
+static void sqlite3Fts5BufferFree(Fts5Buffer*);
+static void sqlite3Fts5BufferZero(Fts5Buffer*);
+static void sqlite3Fts5BufferSet(int*, Fts5Buffer*, int, const u8*);
+static void sqlite3Fts5BufferAppendPrintf(int *, Fts5Buffer*, char *zFmt, ...);
+
+static char *sqlite3Fts5Mprintf(int *pRc, const char *zFmt, ...);
+
+#define fts5BufferZero(x)             sqlite3Fts5BufferZero(x)
+#define fts5BufferAppendVarint(a,b,c) sqlite3Fts5BufferAppendVarint(a,b,(i64)c)
+#define fts5BufferFree(a)             sqlite3Fts5BufferFree(a)
+#define fts5BufferAppendBlob(a,b,c,d) sqlite3Fts5BufferAppendBlob(a,b,c,d)
+#define fts5BufferSet(a,b,c,d)        sqlite3Fts5BufferSet(a,b,c,d)
+
+#define fts5BufferGrow(pRc,pBuf,nn) ( \
+  (u32)((pBuf)->n) + (u32)(nn) <= (u32)((pBuf)->nSpace) ? 0 : \
+    sqlite3Fts5BufferSize((pRc),(pBuf),(nn)+(pBuf)->n) \
+)
+
+/* Write and decode big-endian 32-bit integer values */
+static void sqlite3Fts5Put32(u8*, int);
+static int sqlite3Fts5Get32(const u8*);
+
+#define FTS5_POS2COLUMN(iPos) (int)((iPos >> 32) & 0x7FFFFFFF)
+#define FTS5_POS2OFFSET(iPos) (int)(iPos & 0x7FFFFFFF)
+
+typedef struct Fts5PoslistReader Fts5PoslistReader;
+struct Fts5PoslistReader {
+  /* Variables used only by sqlite3Fts5PoslistIterXXX() functions. */
+  const u8 *a;                    /* Position list to iterate through */
+  int n;                          /* Size of buffer at a[] in bytes */
+  int i;                          /* Current offset in a[] */
+
+  u8 bFlag;                       /* For client use (any custom purpose) */
+
+  /* Output variables */
+  u8 bEof;                        /* Set to true at EOF */
+  i64 iPos;                       /* (iCol<<32) + iPos */
+};
+static int sqlite3Fts5PoslistReaderInit(
+  const u8 *a, int n,             /* Poslist buffer to iterate through */
+  Fts5PoslistReader *pIter        /* Iterator object to initialize */
+);
+static int sqlite3Fts5PoslistReaderNext(Fts5PoslistReader*);
+
+typedef struct Fts5PoslistWriter Fts5PoslistWriter;
+struct Fts5PoslistWriter {
+  i64 iPrev;
+};
+static int sqlite3Fts5PoslistWriterAppend(Fts5Buffer*, Fts5PoslistWriter*, i64);
+static void sqlite3Fts5PoslistSafeAppend(Fts5Buffer*, i64*, i64);
+
+static int sqlite3Fts5PoslistNext64(
+  const u8 *a, int n,             /* Buffer containing poslist */
+  int *pi,                        /* IN/OUT: Offset within a[] */
+  i64 *piOff                      /* IN/OUT: Current offset */
+);
+
+/* Malloc utility */
+static void *sqlite3Fts5MallocZero(int *pRc, sqlite3_int64 nByte);
+static char *sqlite3Fts5Strndup(int *pRc, const char *pIn, int nIn);
+
+/* Character set tests (like isspace(), isalpha() etc.) */
+static int sqlite3Fts5IsBareword(char t);
+
+
+/* Bucket of terms object used by the integrity-check in offsets=0 mode. */
+typedef struct Fts5Termset Fts5Termset;
+static int sqlite3Fts5TermsetNew(Fts5Termset**);
+static int sqlite3Fts5TermsetAdd(Fts5Termset*, int, const char*, int, int *pbPresent);
+static void sqlite3Fts5TermsetFree(Fts5Termset*);
+
+/*
+** End of interface to code in fts5_buffer.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_index.c. fts5_index.c contains contains code
+** to access the data stored in the %_data table.
+*/
+
+typedef struct Fts5Index Fts5Index;
+typedef struct Fts5IndexIter Fts5IndexIter;
+
+struct Fts5IndexIter {
+  i64 iRowid;
+  const u8 *pData;
+  int nData;
+  u8 bEof;
+};
+
+#define sqlite3Fts5IterEof(x) ((x)->bEof)
+
+/*
+** Values used as part of the flags argument passed to IndexQuery().
+*/
+#define FTS5INDEX_QUERY_PREFIX      0x0001  /* Prefix query */
+#define FTS5INDEX_QUERY_DESC        0x0002  /* Docs in descending rowid order */
+#define FTS5INDEX_QUERY_TEST_NOIDX  0x0004  /* Do not use prefix index */
+#define FTS5INDEX_QUERY_SCAN        0x0008  /* Scan query (fts5vocab) */
+
+/* The following are used internally by the fts5_index.c module. They are
+** defined here only to make it easier to avoid clashes with the flags
+** above. */
+#define FTS5INDEX_QUERY_SKIPEMPTY   0x0010
+#define FTS5INDEX_QUERY_NOOUTPUT    0x0020
+#define FTS5INDEX_QUERY_SKIPHASH    0x0040
+#define FTS5INDEX_QUERY_NOTOKENDATA 0x0080
+#define FTS5INDEX_QUERY_SCANONETERM 0x0100
+
+/*
+** Create/destroy an Fts5Index object.
+*/
+static int sqlite3Fts5IndexOpen(Fts5Config *pConfig, int bCreate, Fts5Index**, char**);
+static int sqlite3Fts5IndexClose(Fts5Index *p);
+
+/*
+** Return a simple checksum value based on the arguments.
+*/
+static u64 sqlite3Fts5IndexEntryCksum(
+  i64 iRowid,
+  int iCol,
+  int iPos,
+  int iIdx,
+  const char *pTerm,
+  int nTerm
+);
+
+/*
+** Argument p points to a buffer containing utf-8 text that is n bytes in
+** size. Return the number of bytes in the nChar character prefix of the
+** buffer, or 0 if there are less than nChar characters in total.
+*/
+static int sqlite3Fts5IndexCharlenToBytelen(
+  const char *p,
+  int nByte,
+  int nChar
+);
+
+/*
+** Open a new iterator to iterate though all rowids that match the
+** specified token or token prefix.
+*/
+static int sqlite3Fts5IndexQuery(
+  Fts5Index *p,                   /* FTS index to query */
+  const char *pToken, int nToken, /* Token (or prefix) to query for */
+  int flags,                      /* Mask of FTS5INDEX_QUERY_X flags */
+  Fts5Colset *pColset,            /* Match these columns only */
+  Fts5IndexIter **ppIter          /* OUT: New iterator object */
+);
+
+/*
+** The various operations on open token or token prefix iterators opened
+** using sqlite3Fts5IndexQuery().
+*/
+static int sqlite3Fts5IterNext(Fts5IndexIter*);
+static int sqlite3Fts5IterNextFrom(Fts5IndexIter*, i64 iMatch);
+
+/*
+** Close an iterator opened by sqlite3Fts5IndexQuery().
+*/
+static void sqlite3Fts5IterClose(Fts5IndexIter*);
+
+/*
+** Close the reader blob handle, if it is open.
+*/
+static void sqlite3Fts5IndexCloseReader(Fts5Index*);
+
+/*
+** This interface is used by the fts5vocab module.
+*/
+static const char *sqlite3Fts5IterTerm(Fts5IndexIter*, int*);
+static int sqlite3Fts5IterNextScan(Fts5IndexIter*);
+static void *sqlite3Fts5StructureRef(Fts5Index*);
+static void sqlite3Fts5StructureRelease(void*);
+static int sqlite3Fts5StructureTest(Fts5Index*, void*);
+
+/*
+** Used by xInstToken():
+*/
+static int sqlite3Fts5IterToken(
+  Fts5IndexIter *pIndexIter,
+  const char *pToken, int nToken,
+  i64 iRowid,
+  int iCol,
+  int iOff,
+  const char **ppOut, int *pnOut
+);
+
+/*
+** Insert or remove data to or from the index. Each time a document is
+** added to or removed from the index, this function is called one or more
+** times.
+**
+** For an insert, it must be called once for each token in the new document.
+** If the operation is a delete, it must be called (at least) once for each
+** unique token in the document with an iCol value less than zero. The iPos
+** argument is ignored for a delete.
+*/
+static int sqlite3Fts5IndexWrite(
+  Fts5Index *p,                   /* Index to write to */
+  int iCol,                       /* Column token appears in (-ve -> delete) */
+  int iPos,                       /* Position of token within column */
+  const char *pToken, int nToken  /* Token to add or remove to or from index */
+);
+
+/*
+** Indicate that subsequent calls to sqlite3Fts5IndexWrite() pertain to
+** document iDocid.
+*/
+static int sqlite3Fts5IndexBeginWrite(
+  Fts5Index *p,                   /* Index to write to */
+  int bDelete,                    /* True if current operation is a delete */
+  i64 iDocid                      /* Docid to add or remove data from */
+);
+
+/*
+** Flush any data stored in the in-memory hash tables to the database.
+** Also close any open blob handles.
+*/
+static int sqlite3Fts5IndexSync(Fts5Index *p);
+
+/*
+** Discard any data stored in the in-memory hash tables. Do not write it
+** to the database. Additionally, assume that the contents of the %_data
+** table may have changed on disk. So any in-memory caches of %_data
+** records must be invalidated.
+*/
+static int sqlite3Fts5IndexRollback(Fts5Index *p);
+
+/*
+** Get or set the "averages" values.
+*/
+static int sqlite3Fts5IndexGetAverages(Fts5Index *p, i64 *pnRow, i64 *anSize);
+static int sqlite3Fts5IndexSetAverages(Fts5Index *p, const u8*, int);
+
+/*
+** Functions called by the storage module as part of integrity-check.
+*/
+static int sqlite3Fts5IndexIntegrityCheck(Fts5Index*, u64 cksum, int bUseCksum);
+
+/*
+** Called during virtual module initialization to register UDF
+** fts5_decode() with SQLite
+*/
+static int sqlite3Fts5IndexInit(sqlite3*);
+
+static int sqlite3Fts5IndexSetCookie(Fts5Index*, int);
+
+/*
+** Return the total number of entries read from the %_data table by
+** this connection since it was created.
+*/
+static int sqlite3Fts5IndexReads(Fts5Index *p);
+
+static int sqlite3Fts5IndexReinit(Fts5Index *p);
+static int sqlite3Fts5IndexOptimize(Fts5Index *p);
+static int sqlite3Fts5IndexMerge(Fts5Index *p, int nMerge);
+static int sqlite3Fts5IndexReset(Fts5Index *p);
+
+static int sqlite3Fts5IndexLoadConfig(Fts5Index *p);
+
+static int sqlite3Fts5IndexGetOrigin(Fts5Index *p, i64 *piOrigin);
+static int sqlite3Fts5IndexContentlessDelete(Fts5Index *p, i64 iOrigin, i64 iRowid);
+
+static void sqlite3Fts5IndexIterClearTokendata(Fts5IndexIter*);
+
+/* Used to populate hash tables for xInstToken in detail=none/column mode. */
+static int sqlite3Fts5IndexIterWriteTokendata(
+    Fts5IndexIter*, const char*, int, i64 iRowid, int iCol, int iOff
+);
+
+/*
+** End of interface to code in fts5_index.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_varint.c.
+*/
+static int sqlite3Fts5GetVarint32(const unsigned char *p, u32 *v);
+static int sqlite3Fts5GetVarintLen(u32 iVal);
+static u8 sqlite3Fts5GetVarint(const unsigned char*, u64*);
+static int sqlite3Fts5PutVarint(unsigned char *p, u64 v);
+
+#define fts5GetVarint32(a,b) sqlite3Fts5GetVarint32(a,(u32*)&(b))
+#define fts5GetVarint    sqlite3Fts5GetVarint
+
+#define fts5FastGetVarint32(a, iOff, nVal) {      \
+  nVal = (a)[iOff++];                             \
+  if( nVal & 0x80 ){                              \
+    iOff--;                                       \
+    iOff += fts5GetVarint32(&(a)[iOff], nVal);    \
+  }                                               \
+}
+
+
+/*
+** End of interface to code in fts5_varint.c.
+**************************************************************************/
+
+
+/**************************************************************************
+** Interface to code in fts5_main.c.
+*/
+
+/*
+** Virtual-table object.
+*/
+typedef struct Fts5Table Fts5Table;
+struct Fts5Table {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  Fts5Config *pConfig;            /* Virtual table configuration */
+  Fts5Index *pIndex;              /* Full-text index */
+};
+
+static int sqlite3Fts5LoadTokenizer(Fts5Config *pConfig);
+
+static Fts5Table *sqlite3Fts5TableFromCsrid(Fts5Global*, i64);
+
+static int sqlite3Fts5FlushToDisk(Fts5Table*);
+
+static void sqlite3Fts5ClearLocale(Fts5Config *pConfig);
+static void sqlite3Fts5SetLocale(Fts5Config *pConfig, const char *pLoc, int nLoc);
+
+static int sqlite3Fts5IsLocaleValue(Fts5Config *pConfig, sqlite3_value *pVal);
+static int sqlite3Fts5DecodeLocaleValue(sqlite3_value *pVal,
+    const char **ppText, int *pnText, const char **ppLoc, int *pnLoc
+);
+
+/*
+** End of interface to code in fts5.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_hash.c.
+*/
+typedef struct Fts5Hash Fts5Hash;
+
+/*
+** Create a hash table, free a hash table.
+*/
+static int sqlite3Fts5HashNew(Fts5Config*, Fts5Hash**, int *pnSize);
+static void sqlite3Fts5HashFree(Fts5Hash*);
+
+static int sqlite3Fts5HashWrite(
+  Fts5Hash*,
+  i64 iRowid,                     /* Rowid for this entry */
+  int iCol,                       /* Column token appears in (-ve -> delete) */
+  int iPos,                       /* Position of token within column */
+  char bByte,
+  const char *pToken, int nToken  /* Token to add or remove to or from index */
+);
+
+/*
+** Empty (but do not delete) a hash table.
+*/
+static void sqlite3Fts5HashClear(Fts5Hash*);
+
+/*
+** Return true if the hash is empty, false otherwise.
+*/
+static int sqlite3Fts5HashIsEmpty(Fts5Hash*);
+
+static int sqlite3Fts5HashQuery(
+  Fts5Hash*,                      /* Hash table to query */
+  int nPre,
+  const char *pTerm, int nTerm,   /* Query term */
+  void **ppObj,                   /* OUT: Pointer to doclist for pTerm */
+  int *pnDoclist                  /* OUT: Size of doclist in bytes */
+);
+
+static int sqlite3Fts5HashScanInit(
+  Fts5Hash*,                      /* Hash table to query */
+  const char *pTerm, int nTerm    /* Query prefix */
+);
+static void sqlite3Fts5HashScanNext(Fts5Hash*);
+static int sqlite3Fts5HashScanEof(Fts5Hash*);
+static void sqlite3Fts5HashScanEntry(Fts5Hash *,
+  const char **pzTerm,            /* OUT: term (nul-terminated) */
+  int *pnTerm,                    /* OUT: Size of term in bytes */
+  const u8 **ppDoclist,           /* OUT: pointer to doclist */
+  int *pnDoclist                  /* OUT: size of doclist in bytes */
+);
+
+
+
+/*
+** End of interface to code in fts5_hash.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_storage.c. fts5_storage.c contains contains
+** code to access the data stored in the %_content and %_docsize tables.
+*/
+
+#define FTS5_STMT_SCAN_ASC  0     /* SELECT rowid, * FROM ... ORDER BY 1 ASC */
+#define FTS5_STMT_SCAN_DESC 1     /* SELECT rowid, * FROM ... ORDER BY 1 DESC */
+#define FTS5_STMT_LOOKUP    2     /* SELECT rowid, * FROM ... WHERE rowid=? */
+
+typedef struct Fts5Storage Fts5Storage;
+
+static int sqlite3Fts5StorageOpen(Fts5Config*, Fts5Index*, int, Fts5Storage**, char**);
+static int sqlite3Fts5StorageClose(Fts5Storage *p);
+static int sqlite3Fts5StorageRename(Fts5Storage*, const char *zName);
+
+static int sqlite3Fts5DropAll(Fts5Config*);
+static int sqlite3Fts5CreateTable(Fts5Config*, const char*, const char*, int, char **);
+
+static int sqlite3Fts5StorageDelete(Fts5Storage *p, i64, sqlite3_value**, int);
+static int sqlite3Fts5StorageContentInsert(Fts5Storage *p, int, sqlite3_value**, i64*);
+static int sqlite3Fts5StorageIndexInsert(Fts5Storage *p, sqlite3_value**, i64);
+
+static int sqlite3Fts5StorageIntegrity(Fts5Storage *p, int iArg);
+
+static int sqlite3Fts5StorageStmt(Fts5Storage *p, int eStmt, sqlite3_stmt**, char**);
+static void sqlite3Fts5StorageStmtRelease(Fts5Storage *p, int eStmt, sqlite3_stmt*);
+
+static int sqlite3Fts5StorageDocsize(Fts5Storage *p, i64 iRowid, int *aCol);
+static int sqlite3Fts5StorageSize(Fts5Storage *p, int iCol, i64 *pnAvg);
+static int sqlite3Fts5StorageRowCount(Fts5Storage *p, i64 *pnRow);
+
+static int sqlite3Fts5StorageSync(Fts5Storage *p);
+static int sqlite3Fts5StorageRollback(Fts5Storage *p);
+
+static int sqlite3Fts5StorageConfigValue(
+    Fts5Storage *p, const char*, sqlite3_value*, int
+);
+
+static int sqlite3Fts5StorageDeleteAll(Fts5Storage *p);
+static int sqlite3Fts5StorageRebuild(Fts5Storage *p);
+static int sqlite3Fts5StorageOptimize(Fts5Storage *p);
+static int sqlite3Fts5StorageMerge(Fts5Storage *p, int nMerge);
+static int sqlite3Fts5StorageReset(Fts5Storage *p);
+
+static void sqlite3Fts5StorageReleaseDeleteRow(Fts5Storage*);
+static int sqlite3Fts5StorageFindDeleteRow(Fts5Storage *p, i64 iDel);
+
+/*
+** End of interface to code in fts5_storage.c.
+**************************************************************************/
+
+
+/**************************************************************************
+** Interface to code in fts5_expr.c.
+*/
+typedef struct Fts5Expr Fts5Expr;
+typedef struct Fts5ExprNode Fts5ExprNode;
+typedef struct Fts5Parse Fts5Parse;
+typedef struct Fts5Token Fts5Token;
+typedef struct Fts5ExprPhrase Fts5ExprPhrase;
+typedef struct Fts5ExprNearset Fts5ExprNearset;
+
+struct Fts5Token {
+  const char *p;                  /* Token text (not NULL terminated) */
+  int n;                          /* Size of buffer p in bytes */
+};
+
+/* Parse a MATCH expression. */
+static int sqlite3Fts5ExprNew(
+  Fts5Config *pConfig,
+  int bPhraseToAnd,
+  int iCol,                       /* Column on LHS of MATCH operator */
+  const char *zExpr,
+  Fts5Expr **ppNew,
+  char **pzErr
+);
+static int sqlite3Fts5ExprPattern(
+  Fts5Config *pConfig,
+  int bGlob,
+  int iCol,
+  const char *zText,
+  Fts5Expr **pp
+);
+
+/*
+** for(rc = sqlite3Fts5ExprFirst(pExpr, pIdx, bDesc);
+**     rc==SQLITE_OK && 0==sqlite3Fts5ExprEof(pExpr);
+**     rc = sqlite3Fts5ExprNext(pExpr)
+** ){
+**   // The document with rowid iRowid matches the expression!
+**   i64 iRowid = sqlite3Fts5ExprRowid(pExpr);
+** }
+*/
+static int sqlite3Fts5ExprFirst(Fts5Expr*, Fts5Index *pIdx, i64 iMin, int bDesc);
+static int sqlite3Fts5ExprNext(Fts5Expr*, i64 iMax);
+static int sqlite3Fts5ExprEof(Fts5Expr*);
+static i64 sqlite3Fts5ExprRowid(Fts5Expr*);
+
+static void sqlite3Fts5ExprFree(Fts5Expr*);
+static int sqlite3Fts5ExprAnd(Fts5Expr **pp1, Fts5Expr *p2);
+
+/* Called during startup to register a UDF with SQLite */
+static int sqlite3Fts5ExprInit(Fts5Global*, sqlite3*);
+
+static int sqlite3Fts5ExprPhraseCount(Fts5Expr*);
+static int sqlite3Fts5ExprPhraseSize(Fts5Expr*, int iPhrase);
+static int sqlite3Fts5ExprPoslist(Fts5Expr*, int, const u8 **);
+
+typedef struct Fts5PoslistPopulator Fts5PoslistPopulator;
+static Fts5PoslistPopulator *sqlite3Fts5ExprClearPoslists(Fts5Expr*, int);
+static int sqlite3Fts5ExprPopulatePoslists(
+    Fts5Config*, Fts5Expr*, Fts5PoslistPopulator*, int, const char*, int
+);
+static void sqlite3Fts5ExprCheckPoslists(Fts5Expr*, i64);
+
+static int sqlite3Fts5ExprClonePhrase(Fts5Expr*, int, Fts5Expr**);
+
+static int sqlite3Fts5ExprPhraseCollist(Fts5Expr *, int, const u8 **, int *);
+
+static int sqlite3Fts5ExprQueryToken(Fts5Expr*, int, int, const char**, int*);
+static int sqlite3Fts5ExprInstToken(Fts5Expr*, i64, int, int, int, int, const char**, int*);
+static void sqlite3Fts5ExprClearTokens(Fts5Expr*);
+
+/*******************************************
+** The fts5_expr.c API above this point is used by the other hand-written
+** C code in this module. The interfaces below this point are called by
+** the parser code in fts5parse.y.  */
+
+static void sqlite3Fts5ParseError(Fts5Parse *pParse, const char *zFmt, ...);
+
+static Fts5ExprNode *sqlite3Fts5ParseNode(
+  Fts5Parse *pParse,
+  int eType,
+  Fts5ExprNode *pLeft,
+  Fts5ExprNode *pRight,
+  Fts5ExprNearset *pNear
+);
+
+static Fts5ExprNode *sqlite3Fts5ParseImplicitAnd(
+  Fts5Parse *pParse,
+  Fts5ExprNode *pLeft,
+  Fts5ExprNode *pRight
+);
+
+static Fts5ExprPhrase *sqlite3Fts5ParseTerm(
+  Fts5Parse *pParse,
+  Fts5ExprPhrase *pPhrase,
+  Fts5Token *pToken,
+  int bPrefix
+);
+
+static void sqlite3Fts5ParseSetCaret(Fts5ExprPhrase*);
+
+static Fts5ExprNearset *sqlite3Fts5ParseNearset(
+  Fts5Parse*,
+  Fts5ExprNearset*,
+  Fts5ExprPhrase*
+);
+
+static Fts5Colset *sqlite3Fts5ParseColset(
+  Fts5Parse*,
+  Fts5Colset*,
+  Fts5Token *
+);
+
+static void sqlite3Fts5ParsePhraseFree(Fts5ExprPhrase*);
+static void sqlite3Fts5ParseNearsetFree(Fts5ExprNearset*);
+static void sqlite3Fts5ParseNodeFree(Fts5ExprNode*);
+
+static void sqlite3Fts5ParseSetDistance(Fts5Parse*, Fts5ExprNearset*, Fts5Token*);
+static void sqlite3Fts5ParseSetColset(Fts5Parse*, Fts5ExprNode*, Fts5Colset*);
+static Fts5Colset *sqlite3Fts5ParseColsetInvert(Fts5Parse*, Fts5Colset*);
+static void sqlite3Fts5ParseFinished(Fts5Parse *pParse, Fts5ExprNode *p);
+static void sqlite3Fts5ParseNear(Fts5Parse *pParse, Fts5Token*);
+
+/*
+** End of interface to code in fts5_expr.c.
+**************************************************************************/
+
+
+
+/**************************************************************************
+** Interface to code in fts5_aux.c.
+*/
+
+static int sqlite3Fts5AuxInit(fts5_api*);
+/*
+** End of interface to code in fts5_aux.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_tokenizer.c.
+*/
+
+static int sqlite3Fts5TokenizerInit(fts5_api*);
+static int sqlite3Fts5TokenizerPattern(
+    int (*xCreate)(void*, const char**, int, Fts5Tokenizer**),
+    Fts5Tokenizer *pTok
+);
+static int sqlite3Fts5TokenizerPreload(Fts5TokenizerConfig*);
+/*
+** End of interface to code in fts5_tokenizer.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_vocab.c.
+*/
+
+static int sqlite3Fts5VocabInit(Fts5Global*, sqlite3*);
+
+/*
+** End of interface to code in fts5_vocab.c.
+**************************************************************************/
+
+
+/**************************************************************************
+** Interface to automatically generated code in fts5_unicode2.c.
+*/
+static int sqlite3Fts5UnicodeIsdiacritic(int c);
+static int sqlite3Fts5UnicodeFold(int c, int bRemoveDiacritic);
+
+static int sqlite3Fts5UnicodeCatParse(const char*, u8*);
+static int sqlite3Fts5UnicodeCategory(u32 iCode);
+static void sqlite3Fts5UnicodeAscii(u8*, u8*);
+/*
+** End of interface to code in fts5_unicode2.c.
+**************************************************************************/
+
+#endif
+
+#define FTS5_OR                               1
+#define FTS5_AND                              2
+#define FTS5_NOT                              3
+#define FTS5_TERM                             4
+#define FTS5_COLON                            5
+#define FTS5_MINUS                            6
+#define FTS5_LCP                              7
+#define FTS5_RCP                              8
+#define FTS5_STRING                           9
+#define FTS5_LP                              10
+#define FTS5_RP                              11
+#define FTS5_CARET                           12
+#define FTS5_COMMA                           13
+#define FTS5_PLUS                            14
+#define FTS5_STAR                            15
+
+/* This file is automatically generated by Lemon from input grammar
+** source file "fts5parse.y".
+*/
+/*
+** 2000-05-29
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Driver template for the LEMON parser generator.
+**
+** The "lemon" program processes an LALR(1) input grammar file, then uses
+** this template to construct a parser.  The "lemon" program inserts text
+** at each "%%" line.  Also, any "P-a-r-s-e" identifer prefix (without the
+** interstitial "-" characters) contained in this template is changed into
+** the value of the %name directive from the grammar.  Otherwise, the content
+** of this template is copied straight through into the generate parser
+** source file.
+**
+** The following is the concatenation of all %include directives from the
+** input grammar file:
+*/
+/************ Begin %include sections from the grammar ************************/
+
+/* #include "fts5Int.h" */
+/* #include "fts5parse.h" */
+
+/*
+** Disable all error recovery processing in the parser push-down
+** automaton.
+*/
+#define fts5YYNOERRORRECOVERY 1
+
+/*
+** Make fts5yytestcase() the same as testcase()
+*/
+#define fts5yytestcase(X) testcase(X)
+
+/*
+** Indicate that sqlite3ParserFree() will never be called with a null
+** pointer.
+*/
+#define fts5YYPARSEFREENOTNULL 1
+
+/*
+** Alternative datatype for the argument to the malloc() routine passed
+** into sqlite3ParserAlloc().  The default is size_t.
+*/
+#define fts5YYMALLOCARGTYPE  u64
+
+/**************** End of %include directives **********************************/
+/* These constants specify the various numeric values for terminal symbols.
+***************** Begin token definitions *************************************/
+#ifndef FTS5_OR
+#define FTS5_OR                              1
+#define FTS5_AND                             2
+#define FTS5_NOT                             3
+#define FTS5_TERM                            4
+#define FTS5_COLON                           5
+#define FTS5_MINUS                           6
+#define FTS5_LCP                             7
+#define FTS5_RCP                             8
+#define FTS5_STRING                          9
+#define FTS5_LP                             10
+#define FTS5_RP                             11
+#define FTS5_CARET                          12
+#define FTS5_COMMA                          13
+#define FTS5_PLUS                           14
+#define FTS5_STAR                           15
+#endif
+/**************** End token definitions ***************************************/
+
+/* The next sections is a series of control #defines.
+** various aspects of the generated parser.
+**    fts5YYCODETYPE         is the data type used to store the integer codes
+**                       that represent terminal and non-terminal symbols.
+**                       "unsigned char" is used if there are fewer than
+**                       256 symbols.  Larger types otherwise.
+**    fts5YYNOCODE           is a number of type fts5YYCODETYPE that is not used for
+**                       any terminal or nonterminal symbol.
+**    fts5YYFALLBACK         If defined, this indicates that one or more tokens
+**                       (also known as: "terminal symbols") have fall-back
+**                       values which should be used if the original symbol
+**                       would not parse.  This permits keywords to sometimes
+**                       be used as identifiers, for example.
+**    fts5YYACTIONTYPE       is the data type used for "action codes" - numbers
+**                       that indicate what to do in response to the next
+**                       token.
+**    sqlite3Fts5ParserFTS5TOKENTYPE     is the data type used for minor type for terminal
+**                       symbols.  Background: A "minor type" is a semantic
+**                       value associated with a terminal or non-terminal
+**                       symbols.  For example, for an "ID" terminal symbol,
+**                       the minor type might be the name of the identifier.
+**                       Each non-terminal can have a different minor type.
+**                       Terminal symbols all have the same minor type, though.
+**                       This macros defines the minor type for terminal
+**                       symbols.
+**    fts5YYMINORTYPE        is the data type used for all minor types.
+**                       This is typically a union of many types, one of
+**                       which is sqlite3Fts5ParserFTS5TOKENTYPE.  The entry in the union
+**                       for terminal symbols is called "fts5yy0".
+**    fts5YYSTACKDEPTH       is the maximum depth of the parser's stack.  If
+**                       zero the stack is dynamically sized using realloc()
+**    sqlite3Fts5ParserARG_SDECL     A static variable declaration for the %extra_argument
+**    sqlite3Fts5ParserARG_PDECL     A parameter declaration for the %extra_argument
+**    sqlite3Fts5ParserARG_PARAM     Code to pass %extra_argument as a subroutine parameter
+**    sqlite3Fts5ParserARG_STORE     Code to store %extra_argument into fts5yypParser
+**    sqlite3Fts5ParserARG_FETCH     Code to extract %extra_argument from fts5yypParser
+**    sqlite3Fts5ParserCTX_*         As sqlite3Fts5ParserARG_ except for %extra_context
+**    fts5YYREALLOC          Name of the realloc() function to use
+**    fts5YYFREE             Name of the free() function to use
+**    fts5YYDYNSTACK         True if stack space should be extended on heap
+**    fts5YYERRORSYMBOL      is the code number of the error symbol.  If not
+**                       defined, then do no error processing.
+**    fts5YYNSTATE           the combined number of states.
+**    fts5YYNRULE            the number of rules in the grammar
+**    fts5YYNFTS5TOKEN           Number of terminal symbols
+**    fts5YY_MAX_SHIFT       Maximum value for shift actions
+**    fts5YY_MIN_SHIFTREDUCE Minimum value for shift-reduce actions
+**    fts5YY_MAX_SHIFTREDUCE Maximum value for shift-reduce actions
+**    fts5YY_ERROR_ACTION    The fts5yy_action[] code for syntax error
+**    fts5YY_ACCEPT_ACTION   The fts5yy_action[] code for accept
+**    fts5YY_NO_ACTION       The fts5yy_action[] code for no-op
+**    fts5YY_MIN_REDUCE      Minimum value for reduce actions
+**    fts5YY_MAX_REDUCE      Maximum value for reduce actions
+**    fts5YY_MIN_DSTRCTR     Minimum symbol value that has a destructor
+**    fts5YY_MAX_DSTRCTR     Maximum symbol value that has a destructor
+*/
+#ifndef INTERFACE
+# define INTERFACE 1
+#endif
+/************* Begin control #defines *****************************************/
+#define fts5YYCODETYPE unsigned char
+#define fts5YYNOCODE 27
+#define fts5YYACTIONTYPE unsigned char
+#define sqlite3Fts5ParserFTS5TOKENTYPE Fts5Token
+typedef union {
+  int fts5yyinit;
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yy0;
+  int fts5yy4;
+  Fts5Colset* fts5yy11;
+  Fts5ExprNode* fts5yy24;
+  Fts5ExprNearset* fts5yy46;
+  Fts5ExprPhrase* fts5yy53;
+} fts5YYMINORTYPE;
+#ifndef fts5YYSTACKDEPTH
+#define fts5YYSTACKDEPTH 100
+#endif
+#define sqlite3Fts5ParserARG_SDECL Fts5Parse *pParse;
+#define sqlite3Fts5ParserARG_PDECL ,Fts5Parse *pParse
+#define sqlite3Fts5ParserARG_PARAM ,pParse
+#define sqlite3Fts5ParserARG_FETCH Fts5Parse *pParse=fts5yypParser->pParse;
+#define sqlite3Fts5ParserARG_STORE fts5yypParser->pParse=pParse;
+#define fts5YYREALLOC realloc
+#define fts5YYFREE free
+#define fts5YYDYNSTACK 0
+#define sqlite3Fts5ParserCTX_SDECL
+#define sqlite3Fts5ParserCTX_PDECL
+#define sqlite3Fts5ParserCTX_PARAM
+#define sqlite3Fts5ParserCTX_FETCH
+#define sqlite3Fts5ParserCTX_STORE
+#define fts5YYNSTATE             35
+#define fts5YYNRULE              28
+#define fts5YYNRULE_WITH_ACTION  28
+#define fts5YYNFTS5TOKEN             16
+#define fts5YY_MAX_SHIFT         34
+#define fts5YY_MIN_SHIFTREDUCE   52
+#define fts5YY_MAX_SHIFTREDUCE   79
+#define fts5YY_ERROR_ACTION      80
+#define fts5YY_ACCEPT_ACTION     81
+#define fts5YY_NO_ACTION         82
+#define fts5YY_MIN_REDUCE        83
+#define fts5YY_MAX_REDUCE        110
+#define fts5YY_MIN_DSTRCTR       16
+#define fts5YY_MAX_DSTRCTR       24
+/************* End control #defines *******************************************/
+#define fts5YY_NLOOKAHEAD ((int)(sizeof(fts5yy_lookahead)/sizeof(fts5yy_lookahead[0])))
+
+/* Define the fts5yytestcase() macro to be a no-op if is not already defined
+** otherwise.
+**
+** Applications can choose to define fts5yytestcase() in the %include section
+** to a macro that can assist in verifying code coverage.  For production
+** code the fts5yytestcase() macro should be turned off.  But it is useful
+** for testing.
+*/
+#ifndef fts5yytestcase
+# define fts5yytestcase(X)
+#endif
+
+/* Macro to determine if stack space has the ability to grow using
+** heap memory.
+*/
+#if fts5YYSTACKDEPTH<=0 || fts5YYDYNSTACK
+# define fts5YYGROWABLESTACK 1
+#else
+# define fts5YYGROWABLESTACK 0
+#endif
+
+/* Guarantee a minimum number of initial stack slots.
+*/
+#if fts5YYSTACKDEPTH<=0
+# undef fts5YYSTACKDEPTH
+# define fts5YYSTACKDEPTH 2  /* Need a minimum stack size */
+#endif
+
+
+/* Next are the tables used to determine what action to take based on the
+** current state and lookahead token.  These tables are used to implement
+** functions that take a state number and lookahead value and return an
+** action integer.
+**
+** Suppose the action integer is N.  Then the action is determined as
+** follows
+**
+**   0 <= N <= fts5YY_MAX_SHIFT             Shift N.  That is, push the lookahead
+**                                      token onto the stack and goto state N.
+**
+**   N between fts5YY_MIN_SHIFTREDUCE       Shift to an arbitrary state then
+**     and fts5YY_MAX_SHIFTREDUCE           reduce by rule N-fts5YY_MIN_SHIFTREDUCE.
+**
+**   N == fts5YY_ERROR_ACTION               A syntax error has occurred.
+**
+**   N == fts5YY_ACCEPT_ACTION              The parser accepts its input.
+**
+**   N == fts5YY_NO_ACTION                  No such action.  Denotes unused
+**                                      slots in the fts5yy_action[] table.
+**
+**   N between fts5YY_MIN_REDUCE            Reduce by rule N-fts5YY_MIN_REDUCE
+**     and fts5YY_MAX_REDUCE
+**
+** The action table is constructed as a single large table named fts5yy_action[].
+** Given state S and lookahead X, the action is computed as either:
+**
+**    (A)   N = fts5yy_action[ fts5yy_shift_ofst[S] + X ]
+**    (B)   N = fts5yy_default[S]
+**
+** The (A) formula is preferred.  The B formula is used instead if
+** fts5yy_lookahead[fts5yy_shift_ofst[S]+X] is not equal to X.
+**
+** The formulas above are for computing the action when the lookahead is
+** a terminal symbol.  If the lookahead is a non-terminal (as occurs after
+** a reduce action) then the fts5yy_reduce_ofst[] array is used in place of
+** the fts5yy_shift_ofst[] array.
+**
+** The following are the tables generated in this section:
+**
+**  fts5yy_action[]        A single table containing all actions.
+**  fts5yy_lookahead[]     A table containing the lookahead for each entry in
+**                     fts5yy_action.  Used to detect hash collisions.
+**  fts5yy_shift_ofst[]    For each state, the offset into fts5yy_action for
+**                     shifting terminals.
+**  fts5yy_reduce_ofst[]   For each state, the offset into fts5yy_action for
+**                     shifting non-terminals after a reduce.
+**  fts5yy_default[]       Default action for each state.
+**
+*********** Begin parsing tables **********************************************/
+#define fts5YY_ACTTAB_COUNT (105)
+static const fts5YYACTIONTYPE fts5yy_action[] = {
+ /*     0 */    81,   20,   96,    6,   28,   99,   98,   26,   26,   18,
+ /*    10 */    96,    6,   28,   17,   98,   56,   26,   19,   96,    6,
+ /*    20 */    28,   14,   98,   14,   26,   31,   92,   96,    6,   28,
+ /*    30 */   108,   98,   25,   26,   21,   96,    6,   28,   78,   98,
+ /*    40 */    58,   26,   29,   96,    6,   28,  107,   98,   22,   26,
+ /*    50 */    24,   16,   12,   11,    1,   13,   13,   24,   16,   23,
+ /*    60 */    11,   33,   34,   13,   97,    8,   27,   32,   98,    7,
+ /*    70 */    26,    3,    4,    5,    3,    4,    5,    3,   83,    4,
+ /*    80 */     5,    3,   63,    5,    3,   62,   12,    2,   86,   13,
+ /*    90 */     9,   30,   10,   10,   54,   57,   75,   78,   78,   53,
+ /*   100 */    57,   15,   82,   82,   71,
+};
+static const fts5YYCODETYPE fts5yy_lookahead[] = {
+ /*     0 */    16,   17,   18,   19,   20,   22,   22,   24,   24,   17,
+ /*    10 */    18,   19,   20,    7,   22,    9,   24,   17,   18,   19,
+ /*    20 */    20,    9,   22,    9,   24,   13,   17,   18,   19,   20,
+ /*    30 */    26,   22,   24,   24,   17,   18,   19,   20,   15,   22,
+ /*    40 */     9,   24,   17,   18,   19,   20,   26,   22,   21,   24,
+ /*    50 */     6,    7,    9,    9,   10,   12,   12,    6,    7,   21,
+ /*    60 */     9,   24,   25,   12,   18,    5,   20,   14,   22,    5,
+ /*    70 */    24,    3,    1,    2,    3,    1,    2,    3,    0,    1,
+ /*    80 */     2,    3,   11,    2,    3,   11,    9,   10,    5,   12,
+ /*    90 */    23,   24,   10,   10,    8,    9,    9,   15,   15,    8,
+ /*   100 */     9,    9,   27,   27,   11,   27,   27,   27,   27,   27,
+ /*   110 */    27,   27,   27,   27,   27,   27,   27,   27,   27,   27,
+ /*   120 */    27,
+};
+#define fts5YY_SHIFT_COUNT    (34)
+#define fts5YY_SHIFT_MIN      (0)
+#define fts5YY_SHIFT_MAX      (93)
+static const unsigned char fts5yy_shift_ofst[] = {
+ /*     0 */    44,   44,   44,   44,   44,   44,   51,   77,   43,   12,
+ /*    10 */    14,   83,   82,   14,   23,   23,   31,   31,   71,   74,
+ /*    20 */    78,   81,   86,   91,    6,   53,   53,   60,   64,   68,
+ /*    30 */    53,   87,   92,   53,   93,
+};
+#define fts5YY_REDUCE_COUNT (17)
+#define fts5YY_REDUCE_MIN   (-17)
+#define fts5YY_REDUCE_MAX   (67)
+static const signed char fts5yy_reduce_ofst[] = {
+ /*     0 */   -16,   -8,    0,    9,   17,   25,   46,  -17,  -17,   37,
+ /*    10 */    67,    4,    4,    8,    4,   20,   27,   38,
+};
+static const fts5YYACTIONTYPE fts5yy_default[] = {
+ /*     0 */    80,   80,   80,   80,   80,   80,   95,   80,   80,  105,
+ /*    10 */    80,  110,  110,   80,  110,  110,   80,   80,   80,   80,
+ /*    20 */    80,   91,   80,   80,   80,  101,  100,   80,   80,   90,
+ /*    30 */   103,   80,   80,  104,   80,
+};
+/********** End of lemon-generated parsing tables *****************************/
+
+/* The next table maps tokens (terminal symbols) into fallback tokens.
+** If a construct like the following:
+**
+**      %fallback ID X Y Z.
+**
+** appears in the grammar, then ID becomes a fallback token for X, Y,
+** and Z.  Whenever one of the tokens X, Y, or Z is input to the parser
+** but it does not parse, the type of the token is changed to ID and
+** the parse is retried before an error is thrown.
+**
+** This feature can be used, for example, to cause some keywords in a language
+** to revert to identifiers if they keyword does not apply in the context where
+** it appears.
+*/
+#ifdef fts5YYFALLBACK
+static const fts5YYCODETYPE fts5yyFallback[] = {
+};
+#endif /* fts5YYFALLBACK */
+
+/* The following structure represents a single element of the
+** parser's stack.  Information stored includes:
+**
+**   +  The state number for the parser at this level of the stack.
+**
+**   +  The value of the token stored at this level of the stack.
+**      (In other words, the "major" token.)
+**
+**   +  The semantic value stored at this level of the stack.  This is
+**      the information used by the action routines in the grammar.
+**      It is sometimes called the "minor" token.
+**
+** After the "shift" half of a SHIFTREDUCE action, the stateno field
+** actually contains the reduce action for the second half of the
+** SHIFTREDUCE.
+*/
+struct fts5yyStackEntry {
+  fts5YYACTIONTYPE stateno;  /* The state-number, or reduce action in SHIFTREDUCE */
+  fts5YYCODETYPE major;      /* The major token value.  This is the code
+                         ** number for the token at this stack level */
+  fts5YYMINORTYPE minor;     /* The user-supplied minor token value.  This
+                         ** is the value of the token  */
+};
+typedef struct fts5yyStackEntry fts5yyStackEntry;
+
+/* The state of the parser is completely contained in an instance of
+** the following structure */
+struct fts5yyParser {
+  fts5yyStackEntry *fts5yytos;          /* Pointer to top element of the stack */
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+  int fts5yyhwm;                    /* High-water mark of the stack */
+#endif
+#ifndef fts5YYNOERRORRECOVERY
+  int fts5yyerrcnt;                 /* Shifts left before out of the error */
+#endif
+  sqlite3Fts5ParserARG_SDECL                /* A place to hold %extra_argument */
+  sqlite3Fts5ParserCTX_SDECL                /* A place to hold %extra_context */
+  fts5yyStackEntry *fts5yystackEnd;           /* Last entry in the stack */
+  fts5yyStackEntry *fts5yystack;              /* The parser stack */
+  fts5yyStackEntry fts5yystk0[fts5YYSTACKDEPTH];  /* Initial stack space */
+};
+typedef struct fts5yyParser fts5yyParser;
+
+/* #include <assert.h> */
+#ifndef NDEBUG
+/* #include <stdio.h> */
+static FILE *fts5yyTraceFILE = 0;
+static char *fts5yyTracePrompt = 0;
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/*
+** Turn parser tracing on by giving a stream to which to write the trace
+** and a prompt to preface each trace message.  Tracing is turned off
+** by making either argument NULL
+**
+** Inputs:
+** <ul>
+** <li> A FILE* to which trace output should be written.
+**      If NULL, then tracing is turned off.
+** <li> A prefix string written at the beginning of every
+**      line of trace output.  If NULL, then tracing is
+**      turned off.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+static void sqlite3Fts5ParserTrace(FILE *TraceFILE, char *zTracePrompt){
+  fts5yyTraceFILE = TraceFILE;
+  fts5yyTracePrompt = zTracePrompt;
+  if( fts5yyTraceFILE==0 ) fts5yyTracePrompt = 0;
+  else if( fts5yyTracePrompt==0 ) fts5yyTraceFILE = 0;
+}
+#endif /* NDEBUG */
+
+#if defined(fts5YYCOVERAGE) || !defined(NDEBUG)
+/* For tracing shifts, the names of all terminals and nonterminals
+** are required.  The following table supplies these names */
+static const char *const fts5yyTokenName[] = {
+  /*    0 */ "$",
+  /*    1 */ "OR",
+  /*    2 */ "AND",
+  /*    3 */ "NOT",
+  /*    4 */ "TERM",
+  /*    5 */ "COLON",
+  /*    6 */ "MINUS",
+  /*    7 */ "LCP",
+  /*    8 */ "RCP",
+  /*    9 */ "STRING",
+  /*   10 */ "LP",
+  /*   11 */ "RP",
+  /*   12 */ "CARET",
+  /*   13 */ "COMMA",
+  /*   14 */ "PLUS",
+  /*   15 */ "STAR",
+  /*   16 */ "input",
+  /*   17 */ "expr",
+  /*   18 */ "cnearset",
+  /*   19 */ "exprlist",
+  /*   20 */ "colset",
+  /*   21 */ "colsetlist",
+  /*   22 */ "nearset",
+  /*   23 */ "nearphrases",
+  /*   24 */ "phrase",
+  /*   25 */ "neardist_opt",
+  /*   26 */ "star_opt",
+};
+#endif /* defined(fts5YYCOVERAGE) || !defined(NDEBUG) */
+
+#ifndef NDEBUG
+/* For tracing reduce actions, the names of all rules are required.
+*/
+static const char *const fts5yyRuleName[] = {
+ /*   0 */ "input ::= expr",
+ /*   1 */ "colset ::= MINUS LCP colsetlist RCP",
+ /*   2 */ "colset ::= LCP colsetlist RCP",
+ /*   3 */ "colset ::= STRING",
+ /*   4 */ "colset ::= MINUS STRING",
+ /*   5 */ "colsetlist ::= colsetlist STRING",
+ /*   6 */ "colsetlist ::= STRING",
+ /*   7 */ "expr ::= expr AND expr",
+ /*   8 */ "expr ::= expr OR expr",
+ /*   9 */ "expr ::= expr NOT expr",
+ /*  10 */ "expr ::= colset COLON LP expr RP",
+ /*  11 */ "expr ::= LP expr RP",
+ /*  12 */ "expr ::= exprlist",
+ /*  13 */ "exprlist ::= cnearset",
+ /*  14 */ "exprlist ::= exprlist cnearset",
+ /*  15 */ "cnearset ::= nearset",
+ /*  16 */ "cnearset ::= colset COLON nearset",
+ /*  17 */ "nearset ::= phrase",
+ /*  18 */ "nearset ::= CARET phrase",
+ /*  19 */ "nearset ::= STRING LP nearphrases neardist_opt RP",
+ /*  20 */ "nearphrases ::= phrase",
+ /*  21 */ "nearphrases ::= nearphrases phrase",
+ /*  22 */ "neardist_opt ::=",
+ /*  23 */ "neardist_opt ::= COMMA STRING",
+ /*  24 */ "phrase ::= phrase PLUS STRING star_opt",
+ /*  25 */ "phrase ::= STRING star_opt",
+ /*  26 */ "star_opt ::= STAR",
+ /*  27 */ "star_opt ::=",
+};
+#endif /* NDEBUG */
+
+
+#if fts5YYGROWABLESTACK
+/*
+** Try to increase the size of the parser stack.  Return the number
+** of errors.  Return 0 on success.
+*/
+static int fts5yyGrowStack(fts5yyParser *p){
+  int oldSize = 1 + (int)(p->fts5yystackEnd - p->fts5yystack);
+  int newSize;
+  int idx;
+  fts5yyStackEntry *pNew;
+
+  newSize = oldSize*2 + 100;
+  idx = (int)(p->fts5yytos - p->fts5yystack);
+  if( p->fts5yystack==p->fts5yystk0 ){
+    pNew = fts5YYREALLOC(0, newSize*sizeof(pNew[0]));
+    if( pNew==0 ) return 1;
+    memcpy(pNew, p->fts5yystack, oldSize*sizeof(pNew[0]));
+  }else{
+    pNew = fts5YYREALLOC(p->fts5yystack, newSize*sizeof(pNew[0]));
+    if( pNew==0 ) return 1;
+  }
+  p->fts5yystack = pNew;
+  p->fts5yytos = &p->fts5yystack[idx];
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fprintf(fts5yyTraceFILE,"%sStack grows from %d to %d entries.\n",
+            fts5yyTracePrompt, oldSize, newSize);
+  }
+#endif
+  p->fts5yystackEnd = &p->fts5yystack[newSize-1];
+  return 0;
+}
+#endif /* fts5YYGROWABLESTACK */
+
+#if !fts5YYGROWABLESTACK
+/* For builds that do no have a growable stack, fts5yyGrowStack always
+** returns an error.
+*/
+# define fts5yyGrowStack(X) 1
+#endif
+
+/* Datatype of the argument to the memory allocated passed as the
+** second argument to sqlite3Fts5ParserAlloc() below.  This can be changed by
+** putting an appropriate #define in the %include section of the input
+** grammar.
+*/
+#ifndef fts5YYMALLOCARGTYPE
+# define fts5YYMALLOCARGTYPE size_t
+#endif
+
+/* Initialize a new parser that has already been allocated.
+*/
+static void sqlite3Fts5ParserInit(void *fts5yypRawParser sqlite3Fts5ParserCTX_PDECL){
+  fts5yyParser *fts5yypParser = (fts5yyParser*)fts5yypRawParser;
+  sqlite3Fts5ParserCTX_STORE
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+  fts5yypParser->fts5yyhwm = 0;
+#endif
+  fts5yypParser->fts5yystack = fts5yypParser->fts5yystk0;
+  fts5yypParser->fts5yystackEnd = &fts5yypParser->fts5yystack[fts5YYSTACKDEPTH-1];
+#ifndef fts5YYNOERRORRECOVERY
+  fts5yypParser->fts5yyerrcnt = -1;
+#endif
+  fts5yypParser->fts5yytos = fts5yypParser->fts5yystack;
+  fts5yypParser->fts5yystack[0].stateno = 0;
+  fts5yypParser->fts5yystack[0].major = 0;
+}
+
+#ifndef sqlite3Fts5Parser_ENGINEALWAYSONSTACK
+/*
+** This function allocates a new parser.
+** The only argument is a pointer to a function which works like
+** malloc.
+**
+** Inputs:
+** A pointer to the function used to allocate memory.
+**
+** Outputs:
+** A pointer to a parser.  This pointer is used in subsequent calls
+** to sqlite3Fts5Parser and sqlite3Fts5ParserFree.
+*/
+static void *sqlite3Fts5ParserAlloc(void *(*mallocProc)(fts5YYMALLOCARGTYPE) sqlite3Fts5ParserCTX_PDECL){
+  fts5yyParser *fts5yypParser;
+  fts5yypParser = (fts5yyParser*)(*mallocProc)( (fts5YYMALLOCARGTYPE)sizeof(fts5yyParser) );
+  if( fts5yypParser ){
+    sqlite3Fts5ParserCTX_STORE
+    sqlite3Fts5ParserInit(fts5yypParser sqlite3Fts5ParserCTX_PARAM);
+  }
+  return (void*)fts5yypParser;
+}
+#endif /* sqlite3Fts5Parser_ENGINEALWAYSONSTACK */
+
+
+/* The following function deletes the "minor type" or semantic value
+** associated with a symbol.  The symbol can be either a terminal
+** or nonterminal. "fts5yymajor" is the symbol code, and "fts5yypminor" is
+** a pointer to the value to be deleted.  The code used to do the
+** deletions is derived from the %destructor and/or %token_destructor
+** directives of the input grammar.
+*/
+static void fts5yy_destructor(
+  fts5yyParser *fts5yypParser,    /* The parser */
+  fts5YYCODETYPE fts5yymajor,     /* Type code for object to destroy */
+  fts5YYMINORTYPE *fts5yypminor   /* The object to be destroyed */
+){
+  sqlite3Fts5ParserARG_FETCH
+  sqlite3Fts5ParserCTX_FETCH
+  switch( fts5yymajor ){
+    /* Here is inserted the actions which take place when a
+    ** terminal or non-terminal is destroyed.  This can happen
+    ** when the symbol is popped from the stack during a
+    ** reduce or during error processing or when a parser is
+    ** being destroyed before it is finished parsing.
+    **
+    ** Note: during a reduce, the only symbols destroyed are those
+    ** which appear on the RHS of the rule, but which are *not* used
+    ** inside the C code.
+    */
+/********* Begin destructor definitions ***************************************/
+    case 16: /* input */
+{
+ (void)pParse;
+}
+      break;
+    case 17: /* expr */
+    case 18: /* cnearset */
+    case 19: /* exprlist */
+{
+ sqlite3Fts5ParseNodeFree((fts5yypminor->fts5yy24));
+}
+      break;
+    case 20: /* colset */
+    case 21: /* colsetlist */
+{
+ sqlite3_free((fts5yypminor->fts5yy11));
+}
+      break;
+    case 22: /* nearset */
+    case 23: /* nearphrases */
+{
+ sqlite3Fts5ParseNearsetFree((fts5yypminor->fts5yy46));
+}
+      break;
+    case 24: /* phrase */
+{
+ sqlite3Fts5ParsePhraseFree((fts5yypminor->fts5yy53));
+}
+      break;
+/********* End destructor definitions *****************************************/
+    default:  break;   /* If no destructor action specified: do nothing */
+  }
+}
+
+/*
+** Pop the parser's stack once.
+**
+** If there is a destructor routine associated with the token which
+** is popped from the stack, then call it.
+*/
+static void fts5yy_pop_parser_stack(fts5yyParser *pParser){
+  fts5yyStackEntry *fts5yytos;
+  assert( pParser->fts5yytos!=0 );
+  assert( pParser->fts5yytos > pParser->fts5yystack );
+  fts5yytos = pParser->fts5yytos--;
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fprintf(fts5yyTraceFILE,"%sPopping %s\n",
+      fts5yyTracePrompt,
+      fts5yyTokenName[fts5yytos->major]);
+  }
+#endif
+  fts5yy_destructor(pParser, fts5yytos->major, &fts5yytos->minor);
+}
+
+/*
+** Clear all secondary memory allocations from the parser
+*/
+static void sqlite3Fts5ParserFinalize(void *p){
+  fts5yyParser *pParser = (fts5yyParser*)p;
+
+  /* In-lined version of calling fts5yy_pop_parser_stack() for each
+  ** element left in the stack */
+  fts5yyStackEntry *fts5yytos = pParser->fts5yytos;
+  while( fts5yytos>pParser->fts5yystack ){
+#ifndef NDEBUG
+    if( fts5yyTraceFILE ){
+      fprintf(fts5yyTraceFILE,"%sPopping %s\n",
+        fts5yyTracePrompt,
+        fts5yyTokenName[fts5yytos->major]);
+    }
+#endif
+    if( fts5yytos->major>=fts5YY_MIN_DSTRCTR ){
+      fts5yy_destructor(pParser, fts5yytos->major, &fts5yytos->minor);
+    }
+    fts5yytos--;
+  }
+
+#if fts5YYGROWABLESTACK
+  if( pParser->fts5yystack!=pParser->fts5yystk0 ) fts5YYFREE(pParser->fts5yystack);
+#endif
+}
+
+#ifndef sqlite3Fts5Parser_ENGINEALWAYSONSTACK
+/*
+** Deallocate and destroy a parser.  Destructors are called for
+** all stack elements before shutting the parser down.
+**
+** If the fts5YYPARSEFREENEVERNULL macro exists (for example because it
+** is defined in a %include section of the input grammar) then it is
+** assumed that the input pointer is never NULL.
+*/
+static void sqlite3Fts5ParserFree(
+  void *p,                    /* The parser to be deleted */
+  void (*freeProc)(void*)     /* Function used to reclaim memory */
+){
+#ifndef fts5YYPARSEFREENEVERNULL
+  if( p==0 ) return;
+#endif
+  sqlite3Fts5ParserFinalize(p);
+  (*freeProc)(p);
+}
+#endif /* sqlite3Fts5Parser_ENGINEALWAYSONSTACK */
+
+/*
+** Return the peak depth of the stack for a parser.
+*/
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+static int sqlite3Fts5ParserStackPeak(void *p){
+  fts5yyParser *pParser = (fts5yyParser*)p;
+  return pParser->fts5yyhwm;
+}
+#endif
+
+/* This array of booleans keeps track of the parser statement
+** coverage.  The element fts5yycoverage[X][Y] is set when the parser
+** is in state X and has a lookahead token Y.  In a well-tested
+** systems, every element of this matrix should end up being set.
+*/
+#if defined(fts5YYCOVERAGE)
+static unsigned char fts5yycoverage[fts5YYNSTATE][fts5YYNFTS5TOKEN];
+#endif
+
+/*
+** Write into out a description of every state/lookahead combination that
+**
+**   (1)  has not been used by the parser, and
+**   (2)  is not a syntax error.
+**
+** Return the number of missed state/lookahead combinations.
+*/
+#if defined(fts5YYCOVERAGE)
+static int sqlite3Fts5ParserCoverage(FILE *out){
+  int stateno, iLookAhead, i;
+  int nMissed = 0;
+  for(stateno=0; stateno<fts5YYNSTATE; stateno++){
+    i = fts5yy_shift_ofst[stateno];
+    for(iLookAhead=0; iLookAhead<fts5YYNFTS5TOKEN; iLookAhead++){
+      if( fts5yy_lookahead[i+iLookAhead]!=iLookAhead ) continue;
+      if( fts5yycoverage[stateno][iLookAhead]==0 ) nMissed++;
+      if( out ){
+        fprintf(out,"State %d lookahead %s %s\n", stateno,
+                fts5yyTokenName[iLookAhead],
+                fts5yycoverage[stateno][iLookAhead] ? "ok" : "missed");
+      }
+    }
+  }
+  return nMissed;
+}
+#endif
+
+/*
+** Find the appropriate action for a parser given the terminal
+** look-ahead token iLookAhead.
+*/
+static fts5YYACTIONTYPE fts5yy_find_shift_action(
+  fts5YYCODETYPE iLookAhead,    /* The look-ahead token */
+  fts5YYACTIONTYPE stateno      /* Current state number */
+){
+  int i;
+
+  if( stateno>fts5YY_MAX_SHIFT ) return stateno;
+  assert( stateno <= fts5YY_SHIFT_COUNT );
+#if defined(fts5YYCOVERAGE)
+  fts5yycoverage[stateno][iLookAhead] = 1;
+#endif
+  do{
+    i = fts5yy_shift_ofst[stateno];
+    assert( i>=0 );
+    assert( i<=fts5YY_ACTTAB_COUNT );
+    assert( i+fts5YYNFTS5TOKEN<=(int)fts5YY_NLOOKAHEAD );
+    assert( iLookAhead!=fts5YYNOCODE );
+    assert( iLookAhead < fts5YYNFTS5TOKEN );
+    i += iLookAhead;
+    assert( i<(int)fts5YY_NLOOKAHEAD );
+    if( fts5yy_lookahead[i]!=iLookAhead ){
+#ifdef fts5YYFALLBACK
+      fts5YYCODETYPE iFallback;            /* Fallback token */
+      assert( iLookAhead<sizeof(fts5yyFallback)/sizeof(fts5yyFallback[0]) );
+      iFallback = fts5yyFallback[iLookAhead];
+      if( iFallback!=0 ){
+#ifndef NDEBUG
+        if( fts5yyTraceFILE ){
+          fprintf(fts5yyTraceFILE, "%sFALLBACK %s => %s\n",
+             fts5yyTracePrompt, fts5yyTokenName[iLookAhead], fts5yyTokenName[iFallback]);
+        }
+#endif
+        assert( fts5yyFallback[iFallback]==0 ); /* Fallback loop must terminate */
+        iLookAhead = iFallback;
+        continue;
+      }
+#endif
+#ifdef fts5YYWILDCARD
+      {
+        int j = i - iLookAhead + fts5YYWILDCARD;
+        assert( j<(int)(sizeof(fts5yy_lookahead)/sizeof(fts5yy_lookahead[0])) );
+        if( fts5yy_lookahead[j]==fts5YYWILDCARD && iLookAhead>0 ){
+#ifndef NDEBUG
+          if( fts5yyTraceFILE ){
+            fprintf(fts5yyTraceFILE, "%sWILDCARD %s => %s\n",
+               fts5yyTracePrompt, fts5yyTokenName[iLookAhead],
+               fts5yyTokenName[fts5YYWILDCARD]);
+          }
+#endif /* NDEBUG */
+          return fts5yy_action[j];
+        }
+      }
+#endif /* fts5YYWILDCARD */
+      return fts5yy_default[stateno];
+    }else{
+      assert( i>=0 && i<(int)(sizeof(fts5yy_action)/sizeof(fts5yy_action[0])) );
+      return fts5yy_action[i];
+    }
+  }while(1);
+}
+
+/*
+** Find the appropriate action for a parser given the non-terminal
+** look-ahead token iLookAhead.
+*/
+static fts5YYACTIONTYPE fts5yy_find_reduce_action(
+  fts5YYACTIONTYPE stateno,     /* Current state number */
+  fts5YYCODETYPE iLookAhead     /* The look-ahead token */
+){
+  int i;
+#ifdef fts5YYERRORSYMBOL
+  if( stateno>fts5YY_REDUCE_COUNT ){
+    return fts5yy_default[stateno];
+  }
+#else
+  assert( stateno<=fts5YY_REDUCE_COUNT );
+#endif
+  i = fts5yy_reduce_ofst[stateno];
+  assert( iLookAhead!=fts5YYNOCODE );
+  i += iLookAhead;
+#ifdef fts5YYERRORSYMBOL
+  if( i<0 || i>=fts5YY_ACTTAB_COUNT || fts5yy_lookahead[i]!=iLookAhead ){
+    return fts5yy_default[stateno];
+  }
+#else
+  assert( i>=0 && i<fts5YY_ACTTAB_COUNT );
+  assert( fts5yy_lookahead[i]==iLookAhead );
+#endif
+  return fts5yy_action[i];
+}
+
+/*
+** The following routine is called if the stack overflows.
+*/
+static void fts5yyStackOverflow(fts5yyParser *fts5yypParser){
+   sqlite3Fts5ParserARG_FETCH
+   sqlite3Fts5ParserCTX_FETCH
+#ifndef NDEBUG
+   if( fts5yyTraceFILE ){
+     fprintf(fts5yyTraceFILE,"%sStack Overflow!\n",fts5yyTracePrompt);
+   }
+#endif
+   while( fts5yypParser->fts5yytos>fts5yypParser->fts5yystack ) fts5yy_pop_parser_stack(fts5yypParser);
+   /* Here code is inserted which will execute if the parser
+   ** stack every overflows */
+/******** Begin %stack_overflow code ******************************************/
+
+  sqlite3Fts5ParseError(pParse, "fts5: parser stack overflow");
+/******** End %stack_overflow code ********************************************/
+   sqlite3Fts5ParserARG_STORE /* Suppress warning about unused %extra_argument var */
+   sqlite3Fts5ParserCTX_STORE
+}
+
+/*
+** Print tracing information for a SHIFT action
+*/
+#ifndef NDEBUG
+static void fts5yyTraceShift(fts5yyParser *fts5yypParser, int fts5yyNewState, const char *zTag){
+  if( fts5yyTraceFILE ){
+    if( fts5yyNewState<fts5YYNSTATE ){
+      fprintf(fts5yyTraceFILE,"%s%s '%s', go to state %d\n",
+         fts5yyTracePrompt, zTag, fts5yyTokenName[fts5yypParser->fts5yytos->major],
+         fts5yyNewState);
+    }else{
+      fprintf(fts5yyTraceFILE,"%s%s '%s', pending reduce %d\n",
+         fts5yyTracePrompt, zTag, fts5yyTokenName[fts5yypParser->fts5yytos->major],
+         fts5yyNewState - fts5YY_MIN_REDUCE);
+    }
+  }
+}
+#else
+# define fts5yyTraceShift(X,Y,Z)
+#endif
+
+/*
+** Perform a shift action.
+*/
+static void fts5yy_shift(
+  fts5yyParser *fts5yypParser,          /* The parser to be shifted */
+  fts5YYACTIONTYPE fts5yyNewState,      /* The new state to shift in */
+  fts5YYCODETYPE fts5yyMajor,           /* The major token to shift in */
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yyMinor        /* The minor token to shift in */
+){
+  fts5yyStackEntry *fts5yytos;
+  fts5yypParser->fts5yytos++;
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+  if( (int)(fts5yypParser->fts5yytos - fts5yypParser->fts5yystack)>fts5yypParser->fts5yyhwm ){
+    fts5yypParser->fts5yyhwm++;
+    assert( fts5yypParser->fts5yyhwm == (int)(fts5yypParser->fts5yytos - fts5yypParser->fts5yystack) );
+  }
+#endif
+  fts5yytos = fts5yypParser->fts5yytos;
+  if( fts5yytos>fts5yypParser->fts5yystackEnd ){
+    if( fts5yyGrowStack(fts5yypParser) ){
+      fts5yypParser->fts5yytos--;
+      fts5yyStackOverflow(fts5yypParser);
+      return;
+    }
+    fts5yytos = fts5yypParser->fts5yytos;
+    assert( fts5yytos <= fts5yypParser->fts5yystackEnd );
+  }
+  if( fts5yyNewState > fts5YY_MAX_SHIFT ){
+    fts5yyNewState += fts5YY_MIN_REDUCE - fts5YY_MIN_SHIFTREDUCE;
+  }
+  fts5yytos->stateno = fts5yyNewState;
+  fts5yytos->major = fts5yyMajor;
+  fts5yytos->minor.fts5yy0 = fts5yyMinor;
+  fts5yyTraceShift(fts5yypParser, fts5yyNewState, "Shift");
+}
+
+/* For rule J, fts5yyRuleInfoLhs[J] contains the symbol on the left-hand side
+** of that rule */
+static const fts5YYCODETYPE fts5yyRuleInfoLhs[] = {
+    16,  /* (0) input ::= expr */
+    20,  /* (1) colset ::= MINUS LCP colsetlist RCP */
+    20,  /* (2) colset ::= LCP colsetlist RCP */
+    20,  /* (3) colset ::= STRING */
+    20,  /* (4) colset ::= MINUS STRING */
+    21,  /* (5) colsetlist ::= colsetlist STRING */
+    21,  /* (6) colsetlist ::= STRING */
+    17,  /* (7) expr ::= expr AND expr */
+    17,  /* (8) expr ::= expr OR expr */
+    17,  /* (9) expr ::= expr NOT expr */
+    17,  /* (10) expr ::= colset COLON LP expr RP */
+    17,  /* (11) expr ::= LP expr RP */
+    17,  /* (12) expr ::= exprlist */
+    19,  /* (13) exprlist ::= cnearset */
+    19,  /* (14) exprlist ::= exprlist cnearset */
+    18,  /* (15) cnearset ::= nearset */
+    18,  /* (16) cnearset ::= colset COLON nearset */
+    22,  /* (17) nearset ::= phrase */
+    22,  /* (18) nearset ::= CARET phrase */
+    22,  /* (19) nearset ::= STRING LP nearphrases neardist_opt RP */
+    23,  /* (20) nearphrases ::= phrase */
+    23,  /* (21) nearphrases ::= nearphrases phrase */
+    25,  /* (22) neardist_opt ::= */
+    25,  /* (23) neardist_opt ::= COMMA STRING */
+    24,  /* (24) phrase ::= phrase PLUS STRING star_opt */
+    24,  /* (25) phrase ::= STRING star_opt */
+    26,  /* (26) star_opt ::= STAR */
+    26,  /* (27) star_opt ::= */
+};
+
+/* For rule J, fts5yyRuleInfoNRhs[J] contains the negative of the number
+** of symbols on the right-hand side of that rule. */
+static const signed char fts5yyRuleInfoNRhs[] = {
+   -1,  /* (0) input ::= expr */
+   -4,  /* (1) colset ::= MINUS LCP colsetlist RCP */
+   -3,  /* (2) colset ::= LCP colsetlist RCP */
+   -1,  /* (3) colset ::= STRING */
+   -2,  /* (4) colset ::= MINUS STRING */
+   -2,  /* (5) colsetlist ::= colsetlist STRING */
+   -1,  /* (6) colsetlist ::= STRING */
+   -3,  /* (7) expr ::= expr AND expr */
+   -3,  /* (8) expr ::= expr OR expr */
+   -3,  /* (9) expr ::= expr NOT expr */
+   -5,  /* (10) expr ::= colset COLON LP expr RP */
+   -3,  /* (11) expr ::= LP expr RP */
+   -1,  /* (12) expr ::= exprlist */
+   -1,  /* (13) exprlist ::= cnearset */
+   -2,  /* (14) exprlist ::= exprlist cnearset */
+   -1,  /* (15) cnearset ::= nearset */
+   -3,  /* (16) cnearset ::= colset COLON nearset */
+   -1,  /* (17) nearset ::= phrase */
+   -2,  /* (18) nearset ::= CARET phrase */
+   -5,  /* (19) nearset ::= STRING LP nearphrases neardist_opt RP */
+   -1,  /* (20) nearphrases ::= phrase */
+   -2,  /* (21) nearphrases ::= nearphrases phrase */
+    0,  /* (22) neardist_opt ::= */
+   -2,  /* (23) neardist_opt ::= COMMA STRING */
+   -4,  /* (24) phrase ::= phrase PLUS STRING star_opt */
+   -2,  /* (25) phrase ::= STRING star_opt */
+   -1,  /* (26) star_opt ::= STAR */
+    0,  /* (27) star_opt ::= */
+};
+
+static void fts5yy_accept(fts5yyParser*);  /* Forward Declaration */
+
+/*
+** Perform a reduce action and the shift that must immediately
+** follow the reduce.
+**
+** The fts5yyLookahead and fts5yyLookaheadToken parameters provide reduce actions
+** access to the lookahead token (if any).  The fts5yyLookahead will be fts5YYNOCODE
+** if the lookahead token has already been consumed.  As this procedure is
+** only called from one place, optimizing compilers will in-line it, which
+** means that the extra parameters have no performance impact.
+*/
+static fts5YYACTIONTYPE fts5yy_reduce(
+  fts5yyParser *fts5yypParser,         /* The parser */
+  unsigned int fts5yyruleno,       /* Number of the rule by which to reduce */
+  int fts5yyLookahead,             /* Lookahead token, or fts5YYNOCODE if none */
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yyLookaheadToken  /* Value of the lookahead token */
+  sqlite3Fts5ParserCTX_PDECL                   /* %extra_context */
+){
+  int fts5yygoto;                     /* The next state */
+  fts5YYACTIONTYPE fts5yyact;             /* The next action */
+  fts5yyStackEntry *fts5yymsp;            /* The top of the parser's stack */
+  int fts5yysize;                     /* Amount to pop the stack */
+  sqlite3Fts5ParserARG_FETCH
+  (void)fts5yyLookahead;
+  (void)fts5yyLookaheadToken;
+  fts5yymsp = fts5yypParser->fts5yytos;
+
+  switch( fts5yyruleno ){
+  /* Beginning here are the reduction cases.  A typical example
+  ** follows:
+  **   case 0:
+  **  #line <lineno> <grammarfile>
+  **     { ... }           // User supplied code
+  **  #line <lineno> <thisfile>
+  **     break;
+  */
+/********** Begin reduce actions **********************************************/
+        fts5YYMINORTYPE fts5yylhsminor;
+      case 0: /* input ::= expr */
+{ sqlite3Fts5ParseFinished(pParse, fts5yymsp[0].minor.fts5yy24); }
+        break;
+      case 1: /* colset ::= MINUS LCP colsetlist RCP */
+{
+    fts5yymsp[-3].minor.fts5yy11 = sqlite3Fts5ParseColsetInvert(pParse, fts5yymsp[-1].minor.fts5yy11);
+}
+        break;
+      case 2: /* colset ::= LCP colsetlist RCP */
+{ fts5yymsp[-2].minor.fts5yy11 = fts5yymsp[-1].minor.fts5yy11; }
+        break;
+      case 3: /* colset ::= STRING */
+{
+  fts5yylhsminor.fts5yy11 = sqlite3Fts5ParseColset(pParse, 0, &fts5yymsp[0].minor.fts5yy0);
+}
+  fts5yymsp[0].minor.fts5yy11 = fts5yylhsminor.fts5yy11;
+        break;
+      case 4: /* colset ::= MINUS STRING */
+{
+  fts5yymsp[-1].minor.fts5yy11 = sqlite3Fts5ParseColset(pParse, 0, &fts5yymsp[0].minor.fts5yy0);
+  fts5yymsp[-1].minor.fts5yy11 = sqlite3Fts5ParseColsetInvert(pParse, fts5yymsp[-1].minor.fts5yy11);
+}
+        break;
+      case 5: /* colsetlist ::= colsetlist STRING */
+{
+  fts5yylhsminor.fts5yy11 = sqlite3Fts5ParseColset(pParse, fts5yymsp[-1].minor.fts5yy11, &fts5yymsp[0].minor.fts5yy0); }
+  fts5yymsp[-1].minor.fts5yy11 = fts5yylhsminor.fts5yy11;
+        break;
+      case 6: /* colsetlist ::= STRING */
+{
+  fts5yylhsminor.fts5yy11 = sqlite3Fts5ParseColset(pParse, 0, &fts5yymsp[0].minor.fts5yy0);
+}
+  fts5yymsp[0].minor.fts5yy11 = fts5yylhsminor.fts5yy11;
+        break;
+      case 7: /* expr ::= expr AND expr */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_AND, fts5yymsp[-2].minor.fts5yy24, fts5yymsp[0].minor.fts5yy24, 0);
+}
+  fts5yymsp[-2].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 8: /* expr ::= expr OR expr */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_OR, fts5yymsp[-2].minor.fts5yy24, fts5yymsp[0].minor.fts5yy24, 0);
+}
+  fts5yymsp[-2].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 9: /* expr ::= expr NOT expr */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_NOT, fts5yymsp[-2].minor.fts5yy24, fts5yymsp[0].minor.fts5yy24, 0);
+}
+  fts5yymsp[-2].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 10: /* expr ::= colset COLON LP expr RP */
+{
+  sqlite3Fts5ParseSetColset(pParse, fts5yymsp[-1].minor.fts5yy24, fts5yymsp[-4].minor.fts5yy11);
+  fts5yylhsminor.fts5yy24 = fts5yymsp[-1].minor.fts5yy24;
+}
+  fts5yymsp[-4].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 11: /* expr ::= LP expr RP */
+{fts5yymsp[-2].minor.fts5yy24 = fts5yymsp[-1].minor.fts5yy24;}
+        break;
+      case 12: /* expr ::= exprlist */
+      case 13: /* exprlist ::= cnearset */ fts5yytestcase(fts5yyruleno==13);
+{fts5yylhsminor.fts5yy24 = fts5yymsp[0].minor.fts5yy24;}
+  fts5yymsp[0].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 14: /* exprlist ::= exprlist cnearset */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseImplicitAnd(pParse, fts5yymsp[-1].minor.fts5yy24, fts5yymsp[0].minor.fts5yy24);
+}
+  fts5yymsp[-1].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 15: /* cnearset ::= nearset */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_STRING, 0, 0, fts5yymsp[0].minor.fts5yy46);
+}
+  fts5yymsp[0].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 16: /* cnearset ::= colset COLON nearset */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_STRING, 0, 0, fts5yymsp[0].minor.fts5yy46);
+  sqlite3Fts5ParseSetColset(pParse, fts5yylhsminor.fts5yy24, fts5yymsp[-2].minor.fts5yy11);
+}
+  fts5yymsp[-2].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 17: /* nearset ::= phrase */
+{ fts5yylhsminor.fts5yy46 = sqlite3Fts5ParseNearset(pParse, 0, fts5yymsp[0].minor.fts5yy53); }
+  fts5yymsp[0].minor.fts5yy46 = fts5yylhsminor.fts5yy46;
+        break;
+      case 18: /* nearset ::= CARET phrase */
+{
+  sqlite3Fts5ParseSetCaret(fts5yymsp[0].minor.fts5yy53);
+  fts5yymsp[-1].minor.fts5yy46 = sqlite3Fts5ParseNearset(pParse, 0, fts5yymsp[0].minor.fts5yy53);
+}
+        break;
+      case 19: /* nearset ::= STRING LP nearphrases neardist_opt RP */
+{
+  sqlite3Fts5ParseNear(pParse, &fts5yymsp[-4].minor.fts5yy0);
+  sqlite3Fts5ParseSetDistance(pParse, fts5yymsp[-2].minor.fts5yy46, &fts5yymsp[-1].minor.fts5yy0);
+  fts5yylhsminor.fts5yy46 = fts5yymsp[-2].minor.fts5yy46;
+}
+  fts5yymsp[-4].minor.fts5yy46 = fts5yylhsminor.fts5yy46;
+        break;
+      case 20: /* nearphrases ::= phrase */
+{
+  fts5yylhsminor.fts5yy46 = sqlite3Fts5ParseNearset(pParse, 0, fts5yymsp[0].minor.fts5yy53);
+}
+  fts5yymsp[0].minor.fts5yy46 = fts5yylhsminor.fts5yy46;
+        break;
+      case 21: /* nearphrases ::= nearphrases phrase */
+{
+  fts5yylhsminor.fts5yy46 = sqlite3Fts5ParseNearset(pParse, fts5yymsp[-1].minor.fts5yy46, fts5yymsp[0].minor.fts5yy53);
+}
+  fts5yymsp[-1].minor.fts5yy46 = fts5yylhsminor.fts5yy46;
+        break;
+      case 22: /* neardist_opt ::= */
+{ fts5yymsp[1].minor.fts5yy0.p = 0; fts5yymsp[1].minor.fts5yy0.n = 0; }
+        break;
+      case 23: /* neardist_opt ::= COMMA STRING */
+{ fts5yymsp[-1].minor.fts5yy0 = fts5yymsp[0].minor.fts5yy0; }
+        break;
+      case 24: /* phrase ::= phrase PLUS STRING star_opt */
+{
+  fts5yylhsminor.fts5yy53 = sqlite3Fts5ParseTerm(pParse, fts5yymsp[-3].minor.fts5yy53, &fts5yymsp[-1].minor.fts5yy0, fts5yymsp[0].minor.fts5yy4);
+}
+  fts5yymsp[-3].minor.fts5yy53 = fts5yylhsminor.fts5yy53;
+        break;
+      case 25: /* phrase ::= STRING star_opt */
+{
+  fts5yylhsminor.fts5yy53 = sqlite3Fts5ParseTerm(pParse, 0, &fts5yymsp[-1].minor.fts5yy0, fts5yymsp[0].minor.fts5yy4);
+}
+  fts5yymsp[-1].minor.fts5yy53 = fts5yylhsminor.fts5yy53;
+        break;
+      case 26: /* star_opt ::= STAR */
+{ fts5yymsp[0].minor.fts5yy4 = 1; }
+        break;
+      case 27: /* star_opt ::= */
+{ fts5yymsp[1].minor.fts5yy4 = 0; }
+        break;
+      default:
+        break;
+/********** End reduce actions ************************************************/
+  };
+  assert( fts5yyruleno<sizeof(fts5yyRuleInfoLhs)/sizeof(fts5yyRuleInfoLhs[0]) );
+  fts5yygoto = fts5yyRuleInfoLhs[fts5yyruleno];
+  fts5yysize = fts5yyRuleInfoNRhs[fts5yyruleno];
+  fts5yyact = fts5yy_find_reduce_action(fts5yymsp[fts5yysize].stateno,(fts5YYCODETYPE)fts5yygoto);
+
+  /* There are no SHIFTREDUCE actions on nonterminals because the table
+  ** generator has simplified them to pure REDUCE actions. */
+  assert( !(fts5yyact>fts5YY_MAX_SHIFT && fts5yyact<=fts5YY_MAX_SHIFTREDUCE) );
+
+  /* It is not possible for a REDUCE to be followed by an error */
+  assert( fts5yyact!=fts5YY_ERROR_ACTION );
+
+  fts5yymsp += fts5yysize+1;
+  fts5yypParser->fts5yytos = fts5yymsp;
+  fts5yymsp->stateno = (fts5YYACTIONTYPE)fts5yyact;
+  fts5yymsp->major = (fts5YYCODETYPE)fts5yygoto;
+  fts5yyTraceShift(fts5yypParser, fts5yyact, "... then shift");
+  return fts5yyact;
+}
+
+/*
+** The following code executes when the parse fails
+*/
+#ifndef fts5YYNOERRORRECOVERY
+static void fts5yy_parse_failed(
+  fts5yyParser *fts5yypParser           /* The parser */
+){
+  sqlite3Fts5ParserARG_FETCH
+  sqlite3Fts5ParserCTX_FETCH
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fprintf(fts5yyTraceFILE,"%sFail!\n",fts5yyTracePrompt);
+  }
+#endif
+  while( fts5yypParser->fts5yytos>fts5yypParser->fts5yystack ) fts5yy_pop_parser_stack(fts5yypParser);
+  /* Here code is inserted which will be executed whenever the
+  ** parser fails */
+/************ Begin %parse_failure code ***************************************/
+/************ End %parse_failure code *****************************************/
+  sqlite3Fts5ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3Fts5ParserCTX_STORE
+}
+#endif /* fts5YYNOERRORRECOVERY */
+
+/*
+** The following code executes when a syntax error first occurs.
+*/
+static void fts5yy_syntax_error(
+  fts5yyParser *fts5yypParser,           /* The parser */
+  int fts5yymajor,                   /* The major type of the error token */
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yyminor         /* The minor type of the error token */
+){
+  sqlite3Fts5ParserARG_FETCH
+  sqlite3Fts5ParserCTX_FETCH
+#define FTS5TOKEN fts5yyminor
+/************ Begin %syntax_error code ****************************************/
+
+  UNUSED_PARAM(fts5yymajor); /* Silence a compiler warning */
+  sqlite3Fts5ParseError(
+    pParse, "fts5: syntax error near \"%.*s\"",FTS5TOKEN.n,FTS5TOKEN.p
+  );
+/************ End %syntax_error code ******************************************/
+  sqlite3Fts5ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3Fts5ParserCTX_STORE
+}
+
+/*
+** The following is executed when the parser accepts
+*/
+static void fts5yy_accept(
+  fts5yyParser *fts5yypParser           /* The parser */
+){
+  sqlite3Fts5ParserARG_FETCH
+  sqlite3Fts5ParserCTX_FETCH
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fprintf(fts5yyTraceFILE,"%sAccept!\n",fts5yyTracePrompt);
+  }
+#endif
+#ifndef fts5YYNOERRORRECOVERY
+  fts5yypParser->fts5yyerrcnt = -1;
+#endif
+  assert( fts5yypParser->fts5yytos==fts5yypParser->fts5yystack );
+  /* Here code is inserted which will be executed whenever the
+  ** parser accepts */
+/*********** Begin %parse_accept code *****************************************/
+/*********** End %parse_accept code *******************************************/
+  sqlite3Fts5ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3Fts5ParserCTX_STORE
+}
+
+/* The main parser program.
+** The first argument is a pointer to a structure obtained from
+** "sqlite3Fts5ParserAlloc" which describes the current state of the parser.
+** The second argument is the major token number.  The third is
+** the minor token.  The fourth optional argument is whatever the
+** user wants (and specified in the grammar) and is available for
+** use by the action routines.
+**
+** Inputs:
+** <ul>
+** <li> A pointer to the parser (an opaque structure.)
+** <li> The major token number.
+** <li> The minor token number.
+** <li> An option argument of a grammar-specified type.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+static void sqlite3Fts5Parser(
+  void *fts5yyp,                   /* The parser */
+  int fts5yymajor,                 /* The major token code number */
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yyminor       /* The value for the token */
+  sqlite3Fts5ParserARG_PDECL               /* Optional %extra_argument parameter */
+){
+  fts5YYMINORTYPE fts5yyminorunion;
+  fts5YYACTIONTYPE fts5yyact;   /* The parser action. */
+#if !defined(fts5YYERRORSYMBOL) && !defined(fts5YYNOERRORRECOVERY)
+  int fts5yyendofinput;     /* True if we are at the end of input */
+#endif
+#ifdef fts5YYERRORSYMBOL
+  int fts5yyerrorhit = 0;   /* True if fts5yymajor has invoked an error */
+#endif
+  fts5yyParser *fts5yypParser = (fts5yyParser*)fts5yyp;  /* The parser */
+  sqlite3Fts5ParserCTX_FETCH
+  sqlite3Fts5ParserARG_STORE
+
+  assert( fts5yypParser->fts5yytos!=0 );
+#if !defined(fts5YYERRORSYMBOL) && !defined(fts5YYNOERRORRECOVERY)
+  fts5yyendofinput = (fts5yymajor==0);
+#endif
+
+  fts5yyact = fts5yypParser->fts5yytos->stateno;
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    if( fts5yyact < fts5YY_MIN_REDUCE ){
+      fprintf(fts5yyTraceFILE,"%sInput '%s' in state %d\n",
+              fts5yyTracePrompt,fts5yyTokenName[fts5yymajor],fts5yyact);
+    }else{
+      fprintf(fts5yyTraceFILE,"%sInput '%s' with pending reduce %d\n",
+              fts5yyTracePrompt,fts5yyTokenName[fts5yymajor],fts5yyact-fts5YY_MIN_REDUCE);
+    }
+  }
+#endif
+
+  while(1){ /* Exit by "break" */
+    assert( fts5yypParser->fts5yytos>=fts5yypParser->fts5yystack );
+    assert( fts5yyact==fts5yypParser->fts5yytos->stateno );
+    fts5yyact = fts5yy_find_shift_action((fts5YYCODETYPE)fts5yymajor,fts5yyact);
+    if( fts5yyact >= fts5YY_MIN_REDUCE ){
+      unsigned int fts5yyruleno = fts5yyact - fts5YY_MIN_REDUCE; /* Reduce by this rule */
+#ifndef NDEBUG
+      assert( fts5yyruleno<(int)(sizeof(fts5yyRuleName)/sizeof(fts5yyRuleName[0])) );
+      if( fts5yyTraceFILE ){
+        int fts5yysize = fts5yyRuleInfoNRhs[fts5yyruleno];
+        if( fts5yysize ){
+          fprintf(fts5yyTraceFILE, "%sReduce %d [%s]%s, pop back to state %d.\n",
+            fts5yyTracePrompt,
+            fts5yyruleno, fts5yyRuleName[fts5yyruleno],
+            fts5yyruleno<fts5YYNRULE_WITH_ACTION ? "" : " without external action",
+            fts5yypParser->fts5yytos[fts5yysize].stateno);
+        }else{
+          fprintf(fts5yyTraceFILE, "%sReduce %d [%s]%s.\n",
+            fts5yyTracePrompt, fts5yyruleno, fts5yyRuleName[fts5yyruleno],
+            fts5yyruleno<fts5YYNRULE_WITH_ACTION ? "" : " without external action");
+        }
+      }
+#endif /* NDEBUG */
+
+      /* Check that the stack is large enough to grow by a single entry
+      ** if the RHS of the rule is empty.  This ensures that there is room
+      ** enough on the stack to push the LHS value */
+      if( fts5yyRuleInfoNRhs[fts5yyruleno]==0 ){
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+        if( (int)(fts5yypParser->fts5yytos - fts5yypParser->fts5yystack)>fts5yypParser->fts5yyhwm ){
+          fts5yypParser->fts5yyhwm++;
+          assert( fts5yypParser->fts5yyhwm ==
+                  (int)(fts5yypParser->fts5yytos - fts5yypParser->fts5yystack));
+        }
+#endif
+        if( fts5yypParser->fts5yytos>=fts5yypParser->fts5yystackEnd ){
+          if( fts5yyGrowStack(fts5yypParser) ){
+            fts5yyStackOverflow(fts5yypParser);
+            break;
+          }
+        }
+      }
+      fts5yyact = fts5yy_reduce(fts5yypParser,fts5yyruleno,fts5yymajor,fts5yyminor sqlite3Fts5ParserCTX_PARAM);
+    }else if( fts5yyact <= fts5YY_MAX_SHIFTREDUCE ){
+      fts5yy_shift(fts5yypParser,fts5yyact,(fts5YYCODETYPE)fts5yymajor,fts5yyminor);
+#ifndef fts5YYNOERRORRECOVERY
+      fts5yypParser->fts5yyerrcnt--;
+#endif
+      break;
+    }else if( fts5yyact==fts5YY_ACCEPT_ACTION ){
+      fts5yypParser->fts5yytos--;
+      fts5yy_accept(fts5yypParser);
+      return;
+    }else{
+      assert( fts5yyact == fts5YY_ERROR_ACTION );
+      fts5yyminorunion.fts5yy0 = fts5yyminor;
+#ifdef fts5YYERRORSYMBOL
+      int fts5yymx;
+#endif
+#ifndef NDEBUG
+      if( fts5yyTraceFILE ){
+        fprintf(fts5yyTraceFILE,"%sSyntax Error!\n",fts5yyTracePrompt);
+      }
+#endif
+#ifdef fts5YYERRORSYMBOL
+      /* A syntax error has occurred.
+      ** The response to an error depends upon whether or not the
+      ** grammar defines an error token "ERROR".
+      **
+      ** This is what we do if the grammar does define ERROR:
+      **
+      **  * Call the %syntax_error function.
+      **
+      **  * Begin popping the stack until we enter a state where
+      **    it is legal to shift the error symbol, then shift
+      **    the error symbol.
+      **
+      **  * Set the error count to three.
+      **
+      **  * Begin accepting and shifting new tokens.  No new error
+      **    processing will occur until three tokens have been
+      **    shifted successfully.
+      **
+      */
+      if( fts5yypParser->fts5yyerrcnt<0 ){
+        fts5yy_syntax_error(fts5yypParser,fts5yymajor,fts5yyminor);
+      }
+      fts5yymx = fts5yypParser->fts5yytos->major;
+      if( fts5yymx==fts5YYERRORSYMBOL || fts5yyerrorhit ){
+#ifndef NDEBUG
+        if( fts5yyTraceFILE ){
+          fprintf(fts5yyTraceFILE,"%sDiscard input token %s\n",
+             fts5yyTracePrompt,fts5yyTokenName[fts5yymajor]);
+        }
+#endif
+        fts5yy_destructor(fts5yypParser, (fts5YYCODETYPE)fts5yymajor, &fts5yyminorunion);
+        fts5yymajor = fts5YYNOCODE;
+      }else{
+        while( fts5yypParser->fts5yytos > fts5yypParser->fts5yystack ){
+          fts5yyact = fts5yy_find_reduce_action(fts5yypParser->fts5yytos->stateno,
+                                        fts5YYERRORSYMBOL);
+          if( fts5yyact<=fts5YY_MAX_SHIFTREDUCE ) break;
+          fts5yy_pop_parser_stack(fts5yypParser);
+        }
+        if( fts5yypParser->fts5yytos <= fts5yypParser->fts5yystack || fts5yymajor==0 ){
+          fts5yy_destructor(fts5yypParser,(fts5YYCODETYPE)fts5yymajor,&fts5yyminorunion);
+          fts5yy_parse_failed(fts5yypParser);
+#ifndef fts5YYNOERRORRECOVERY
+          fts5yypParser->fts5yyerrcnt = -1;
+#endif
+          fts5yymajor = fts5YYNOCODE;
+        }else if( fts5yymx!=fts5YYERRORSYMBOL ){
+          fts5yy_shift(fts5yypParser,fts5yyact,fts5YYERRORSYMBOL,fts5yyminor);
+        }
+      }
+      fts5yypParser->fts5yyerrcnt = 3;
+      fts5yyerrorhit = 1;
+      if( fts5yymajor==fts5YYNOCODE ) break;
+      fts5yyact = fts5yypParser->fts5yytos->stateno;
+#elif defined(fts5YYNOERRORRECOVERY)
+      /* If the fts5YYNOERRORRECOVERY macro is defined, then do not attempt to
+      ** do any kind of error recovery.  Instead, simply invoke the syntax
+      ** error routine and continue going as if nothing had happened.
+      **
+      ** Applications can set this macro (for example inside %include) if
+      ** they intend to abandon the parse upon the first syntax error seen.
+      */
+      fts5yy_syntax_error(fts5yypParser,fts5yymajor, fts5yyminor);
+      fts5yy_destructor(fts5yypParser,(fts5YYCODETYPE)fts5yymajor,&fts5yyminorunion);
+      break;
+#else  /* fts5YYERRORSYMBOL is not defined */
+      /* This is what we do if the grammar does not define ERROR:
+      **
+      **  * Report an error message, and throw away the input token.
+      **
+      **  * If the input token is $, then fail the parse.
+      **
+      ** As before, subsequent error messages are suppressed until
+      ** three input tokens have been successfully shifted.
+      */
+      if( fts5yypParser->fts5yyerrcnt<=0 ){
+        fts5yy_syntax_error(fts5yypParser,fts5yymajor, fts5yyminor);
+      }
+      fts5yypParser->fts5yyerrcnt = 3;
+      fts5yy_destructor(fts5yypParser,(fts5YYCODETYPE)fts5yymajor,&fts5yyminorunion);
+      if( fts5yyendofinput ){
+        fts5yy_parse_failed(fts5yypParser);
+#ifndef fts5YYNOERRORRECOVERY
+        fts5yypParser->fts5yyerrcnt = -1;
+#endif
+      }
+      break;
+#endif
+    }
+  }
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fts5yyStackEntry *i;
+    char cDiv = '[';
+    fprintf(fts5yyTraceFILE,"%sReturn. Stack=",fts5yyTracePrompt);
+    for(i=&fts5yypParser->fts5yystack[1]; i<=fts5yypParser->fts5yytos; i++){
+      fprintf(fts5yyTraceFILE,"%c%s", cDiv, fts5yyTokenName[i->major]);
+      cDiv = ' ';
+    }
+    fprintf(fts5yyTraceFILE,"]\n");
+  }
+#endif
+  return;
+}
+
+/*
+** Return the fallback token corresponding to canonical token iToken, or
+** 0 if iToken has no fallback.
+*/
+static int sqlite3Fts5ParserFallback(int iToken){
+#ifdef fts5YYFALLBACK
+  assert( iToken<(int)(sizeof(fts5yyFallback)/sizeof(fts5yyFallback[0])) );
+  return fts5yyFallback[iToken];
+#else
+  (void)iToken;
+  return 0;
+#endif
+}
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+
+/* #include "fts5Int.h" */
+#include <math.h>                 /* amalgamator: keep */
+
+/*
+** Object used to iterate through all "coalesced phrase instances" in
+** a single column of the current row. If the phrase instances in the
+** column being considered do not overlap, this object simply iterates
+** through them. Or, if they do overlap (share one or more tokens in
+** common), each set of overlapping instances is treated as a single
+** match. See documentation for the highlight() auxiliary function for
+** details.
+**
+** Usage is:
+**
+**   for(rc = fts5CInstIterNext(pApi, pFts, iCol, &iter);
+**      (rc==SQLITE_OK && 0==fts5CInstIterEof(&iter);
+**      rc = fts5CInstIterNext(&iter)
+**   ){
+**     printf("instance starts at %d, ends at %d\n", iter.iStart, iter.iEnd);
+**   }
+**
+*/
+typedef struct CInstIter CInstIter;
+struct CInstIter {
+  const Fts5ExtensionApi *pApi;   /* API offered by current FTS version */
+  Fts5Context *pFts;              /* First arg to pass to pApi functions */
+  int iCol;                       /* Column to search */
+  int iInst;                      /* Next phrase instance index */
+  int nInst;                      /* Total number of phrase instances */
+
+  /* Output variables */
+  int iStart;                     /* First token in coalesced phrase instance */
+  int iEnd;                       /* Last token in coalesced phrase instance */
+};
+
+/*
+** Advance the iterator to the next coalesced phrase instance. Return
+** an SQLite error code if an error occurs, or SQLITE_OK otherwise.
+*/
+static int fts5CInstIterNext(CInstIter *pIter){
+  int rc = SQLITE_OK;
+  pIter->iStart = -1;
+  pIter->iEnd = -1;
+
+  while( rc==SQLITE_OK && pIter->iInst<pIter->nInst ){
+    int ip; int ic; int io;
+    rc = pIter->pApi->xInst(pIter->pFts, pIter->iInst, &ip, &ic, &io);
+    if( rc==SQLITE_OK ){
+      if( ic==pIter->iCol ){
+        int iEnd = io - 1 + pIter->pApi->xPhraseSize(pIter->pFts, ip);
+        if( pIter->iStart<0 ){
+          pIter->iStart = io;
+          pIter->iEnd = iEnd;
+        }else if( io<=pIter->iEnd ){
+          if( iEnd>pIter->iEnd ) pIter->iEnd = iEnd;
+        }else{
+          break;
+        }
+      }
+      pIter->iInst++;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Initialize the iterator object indicated by the final parameter to
+** iterate through coalesced phrase instances in column iCol.
+*/
+static int fts5CInstIterInit(
+  const Fts5ExtensionApi *pApi,
+  Fts5Context *pFts,
+  int iCol,
+  CInstIter *pIter
+){
+  int rc;
+
+  memset(pIter, 0, sizeof(CInstIter));
+  pIter->pApi = pApi;
+  pIter->pFts = pFts;
+  pIter->iCol = iCol;
+  rc = pApi->xInstCount(pFts, &pIter->nInst);
+
+  if( rc==SQLITE_OK ){
+    rc = fts5CInstIterNext(pIter);
+  }
+
+  return rc;
+}
+
+
+
+/*************************************************************************
+** Start of highlight() implementation.
+*/
+typedef struct HighlightContext HighlightContext;
+struct HighlightContext {
+  /* Constant parameters to fts5HighlightCb() */
+  int iRangeStart;                /* First token to include */
+  int iRangeEnd;                  /* If non-zero, last token to include */
+  const char *zOpen;              /* Opening highlight */
+  const char *zClose;             /* Closing highlight */
+  const char *zIn;                /* Input text */
+  int nIn;                        /* Size of input text in bytes */
+
+  /* Variables modified by fts5HighlightCb() */
+  CInstIter iter;                 /* Coalesced Instance Iterator */
+  int iPos;                       /* Current token offset in zIn[] */
+  int iOff;                       /* Have copied up to this offset in zIn[] */
+  int bOpen;                      /* True if highlight is open */
+  char *zOut;                     /* Output value */
+};
+
+/*
+** Append text to the HighlightContext output string - p->zOut. Argument
+** z points to a buffer containing n bytes of text to append. If n is
+** negative, everything up until the first '\0' is appended to the output.
+**
+** If *pRc is set to any value other than SQLITE_OK when this function is
+** called, it is a no-op. If an error (i.e. an OOM condition) is encountered,
+** *pRc is set to an error code before returning.
+*/
+static void fts5HighlightAppend(
+  int *pRc,
+  HighlightContext *p,
+  const char *z, int n
+){
+  if( *pRc==SQLITE_OK && z ){
+    if( n<0 ) n = (int)strlen(z);
+    p->zOut = sqlite3_mprintf("%z%.*s", p->zOut, n, z);
+    if( p->zOut==0 ) *pRc = SQLITE_NOMEM;
+  }
+}
+
+/*
+** Tokenizer callback used by implementation of highlight() function.
+*/
+static int fts5HighlightCb(
+  void *pContext,                 /* Pointer to HighlightContext object */
+  int tflags,                     /* Mask of FTS5_TOKEN_* flags */
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iStartOff,                  /* Start byte offset of token */
+  int iEndOff                     /* End byte offset of token */
+){
+  HighlightContext *p = (HighlightContext*)pContext;
+  int rc = SQLITE_OK;
+  int iPos;
+
+  UNUSED_PARAM2(pToken, nToken);
+
+  if( tflags & FTS5_TOKEN_COLOCATED ) return SQLITE_OK;
+  iPos = p->iPos++;
+
+  if( p->iRangeEnd>=0 ){
+    if( iPos<p->iRangeStart || iPos>p->iRangeEnd ) return SQLITE_OK;
+    if( p->iRangeStart && iPos==p->iRangeStart ) p->iOff = iStartOff;
+  }
+
+  /* If the parenthesis is open, and this token is not part of the current
+  ** phrase, and the starting byte offset of this token is past the point
+  ** that has currently been copied into the output buffer, close the
+  ** parenthesis. */
+  if( p->bOpen
+   && (iPos<=p->iter.iStart || p->iter.iStart<0)
+   && iStartOff>p->iOff
+  ){
+    fts5HighlightAppend(&rc, p, p->zClose, -1);
+    p->bOpen = 0;
+  }
+
+  /* If this is the start of a new phrase, and the highlight is not open:
+  **
+  **   * copy text from the input up to the start of the phrase, and
+  **   * open the highlight.
+  */
+  if( iPos==p->iter.iStart && p->bOpen==0 ){
+    fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iStartOff - p->iOff);
+    fts5HighlightAppend(&rc, p, p->zOpen, -1);
+    p->iOff = iStartOff;
+    p->bOpen = 1;
+  }
+
+  if( iPos==p->iter.iEnd ){
+    if( p->bOpen==0 ){
+      assert( p->iRangeEnd>=0 );
+      fts5HighlightAppend(&rc, p, p->zOpen, -1);
+      p->bOpen = 1;
+    }
+    fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iEndOff - p->iOff);
+    p->iOff = iEndOff;
+
+    if( rc==SQLITE_OK ){
+      rc = fts5CInstIterNext(&p->iter);
+    }
+  }
+
+  if( iPos==p->iRangeEnd ){
+    if( p->bOpen ){
+      if( p->iter.iStart>=0 && iPos>=p->iter.iStart ){
+        fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iEndOff - p->iOff);
+        p->iOff = iEndOff;
+      }
+      fts5HighlightAppend(&rc, p, p->zClose, -1);
+      p->bOpen = 0;
+    }
+    fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iEndOff - p->iOff);
+    p->iOff = iEndOff;
+  }
+
+  return rc;
+}
+
+
+/*
+** Implementation of highlight() function.
+*/
+static void fts5HighlightFunction(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+){
+  HighlightContext ctx;
+  int rc;
+  int iCol;
+
+  if( nVal!=3 ){
+    const char *zErr = "wrong number of arguments to function highlight()";
+    sqlite3_result_error(pCtx, zErr, -1);
+    return;
+  }
+
+  iCol = sqlite3_value_int(apVal[0]);
+  memset(&ctx, 0, sizeof(HighlightContext));
+  ctx.zOpen = (const char*)sqlite3_value_text(apVal[1]);
+  ctx.zClose = (const char*)sqlite3_value_text(apVal[2]);
+  ctx.iRangeEnd = -1;
+  rc = pApi->xColumnText(pFts, iCol, &ctx.zIn, &ctx.nIn);
+  if( rc==SQLITE_RANGE ){
+    sqlite3_result_text(pCtx, "", -1, SQLITE_STATIC);
+    rc = SQLITE_OK;
+  }else if( ctx.zIn ){
+    const char *pLoc = 0;         /* Locale of column iCol */
+    int nLoc = 0;                 /* Size of pLoc in bytes */
+    if( rc==SQLITE_OK ){
+      rc = fts5CInstIterInit(pApi, pFts, iCol, &ctx.iter);
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = pApi->xColumnLocale(pFts, iCol, &pLoc, &nLoc);
+    }
+    if( rc==SQLITE_OK ){
+      rc = pApi->xTokenize_v2(
+          pFts, ctx.zIn, ctx.nIn, pLoc, nLoc, (void*)&ctx, fts5HighlightCb
+      );
+    }
+    if( ctx.bOpen ){
+      fts5HighlightAppend(&rc, &ctx, ctx.zClose, -1);
+    }
+    fts5HighlightAppend(&rc, &ctx, &ctx.zIn[ctx.iOff], ctx.nIn - ctx.iOff);
+
+    if( rc==SQLITE_OK ){
+      sqlite3_result_text(pCtx, (const char*)ctx.zOut, -1, SQLITE_TRANSIENT);
+    }
+    sqlite3_free(ctx.zOut);
+  }
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+  }
+}
+/*
+** End of highlight() implementation.
+**************************************************************************/
+
+/*
+** Context object passed to the fts5SentenceFinderCb() function.
+*/
+typedef struct Fts5SFinder Fts5SFinder;
+struct Fts5SFinder {
+  int iPos;                       /* Current token position */
+  int nFirstAlloc;                /* Allocated size of aFirst[] */
+  int nFirst;                     /* Number of entries in aFirst[] */
+  int *aFirst;                    /* Array of first token in each sentence */
+  const char *zDoc;               /* Document being tokenized */
+};
+
+/*
+** Add an entry to the Fts5SFinder.aFirst[] array. Grow the array if
+** necessary. Return SQLITE_OK if successful, or SQLITE_NOMEM if an
+** error occurs.
+*/
+static int fts5SentenceFinderAdd(Fts5SFinder *p, int iAdd){
+  if( p->nFirstAlloc==p->nFirst ){
+    int nNew = p->nFirstAlloc ? p->nFirstAlloc*2 : 64;
+    int *aNew;
+
+    aNew = (int*)sqlite3_realloc64(p->aFirst, nNew*sizeof(int));
+    if( aNew==0 ) return SQLITE_NOMEM;
+    p->aFirst = aNew;
+    p->nFirstAlloc = nNew;
+  }
+  p->aFirst[p->nFirst++] = iAdd;
+  return SQLITE_OK;
+}
+
+/*
+** This function is an xTokenize() callback used by the auxiliary snippet()
+** function. Its job is to identify tokens that are the first in a sentence.
+** For each such token, an entry is added to the SFinder.aFirst[] array.
+*/
+static int fts5SentenceFinderCb(
+  void *pContext,                 /* Pointer to HighlightContext object */
+  int tflags,                     /* Mask of FTS5_TOKEN_* flags */
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iStartOff,                  /* Start offset of token */
+  int iEndOff                     /* End offset of token */
+){
+  int rc = SQLITE_OK;
+
+  UNUSED_PARAM2(pToken, nToken);
+  UNUSED_PARAM(iEndOff);
+
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 ){
+    Fts5SFinder *p = (Fts5SFinder*)pContext;
+    if( p->iPos>0 ){
+      int i;
+      char c = 0;
+      for(i=iStartOff-1; i>=0; i--){
+        c = p->zDoc[i];
+        if( c!=' ' && c!='\t' && c!='\n' && c!='\r' ) break;
+      }
+      if( i!=iStartOff-1 && (c=='.' || c==':') ){
+        rc = fts5SentenceFinderAdd(p, p->iPos);
+      }
+    }else{
+      rc = fts5SentenceFinderAdd(p, 0);
+    }
+    p->iPos++;
+  }
+  return rc;
+}
+
+static int fts5SnippetScore(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  int nDocsize,                   /* Size of column in tokens */
+  unsigned char *aSeen,           /* Array with one element per query phrase */
+  int iCol,                       /* Column to score */
+  int iPos,                       /* Starting offset to score */
+  int nToken,                     /* Max tokens per snippet */
+  int *pnScore,                   /* OUT: Score */
+  int *piPos                      /* OUT: Adjusted offset */
+){
+  int rc;
+  int i;
+  int ip = 0;
+  int ic = 0;
+  int iOff = 0;
+  int iFirst = -1;
+  int nInst;
+  int nScore = 0;
+  int iLast = 0;
+  sqlite3_int64 iEnd = (sqlite3_int64)iPos + nToken;
+
+  rc = pApi->xInstCount(pFts, &nInst);
+  for(i=0; i<nInst && rc==SQLITE_OK; i++){
+    rc = pApi->xInst(pFts, i, &ip, &ic, &iOff);
+    if( rc==SQLITE_OK && ic==iCol && iOff>=iPos && iOff<iEnd ){
+      nScore += (aSeen[ip] ? 1 : 1000);
+      aSeen[ip] = 1;
+      if( iFirst<0 ) iFirst = iOff;
+      iLast = iOff + pApi->xPhraseSize(pFts, ip);
+    }
+  }
+
+  *pnScore = nScore;
+  if( piPos ){
+    sqlite3_int64 iAdj = iFirst - (nToken - (iLast-iFirst)) / 2;
+    if( (iAdj+nToken)>nDocsize ) iAdj = nDocsize - nToken;
+    if( iAdj<0 ) iAdj = 0;
+    *piPos = (int)iAdj;
+  }
+
+  return rc;
+}
+
+/*
+** Return the value in pVal interpreted as utf-8 text. Except, if pVal
+** contains a NULL value, return a pointer to a static string zero
+** bytes in length instead of a NULL pointer.
+*/
+static const char *fts5ValueToText(sqlite3_value *pVal){
+  const char *zRet = (const char*)sqlite3_value_text(pVal);
+  return zRet ? zRet : "";
+}
+
+/*
+** Implementation of snippet() function.
+*/
+static void fts5SnippetFunction(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+){
+  HighlightContext ctx;
+  int rc = SQLITE_OK;             /* Return code */
+  int iCol;                       /* 1st argument to snippet() */
+  const char *zEllips;            /* 4th argument to snippet() */
+  int nToken;                     /* 5th argument to snippet() */
+  int nInst = 0;                  /* Number of instance matches this row */
+  int i;                          /* Used to iterate through instances */
+  int nPhrase;                    /* Number of phrases in query */
+  unsigned char *aSeen;           /* Array of "seen instance" flags */
+  int iBestCol;                   /* Column containing best snippet */
+  int iBestStart = 0;             /* First token of best snippet */
+  int nBestScore = 0;             /* Score of best snippet */
+  int nColSize = 0;               /* Total size of iBestCol in tokens */
+  Fts5SFinder sFinder;            /* Used to find the beginnings of sentences */
+  int nCol;
+
+  if( nVal!=5 ){
+    const char *zErr = "wrong number of arguments to function snippet()";
+    sqlite3_result_error(pCtx, zErr, -1);
+    return;
+  }
+
+  nCol = pApi->xColumnCount(pFts);
+  memset(&ctx, 0, sizeof(HighlightContext));
+  iCol = sqlite3_value_int(apVal[0]);
+  ctx.zOpen = fts5ValueToText(apVal[1]);
+  ctx.zClose = fts5ValueToText(apVal[2]);
+  ctx.iRangeEnd = -1;
+  zEllips = fts5ValueToText(apVal[3]);
+  nToken = sqlite3_value_int(apVal[4]);
+
+  iBestCol = (iCol>=0 ? iCol : 0);
+  nPhrase = pApi->xPhraseCount(pFts);
+  aSeen = sqlite3_malloc(nPhrase);
+  if( aSeen==0 ){
+    rc = SQLITE_NOMEM;
+  }
+  if( rc==SQLITE_OK ){
+    rc = pApi->xInstCount(pFts, &nInst);
+  }
+
+  memset(&sFinder, 0, sizeof(Fts5SFinder));
+  for(i=0; i<nCol; i++){
+    if( iCol<0 || iCol==i ){
+      const char *pLoc = 0;       /* Locale of column iCol */
+      int nLoc = 0;               /* Size of pLoc in bytes */
+      int nDoc;
+      int nDocsize;
+      int ii;
+      sFinder.iPos = 0;
+      sFinder.nFirst = 0;
+      rc = pApi->xColumnText(pFts, i, &sFinder.zDoc, &nDoc);
+      if( rc!=SQLITE_OK ) break;
+      rc = pApi->xColumnLocale(pFts, i, &pLoc, &nLoc);
+      if( rc!=SQLITE_OK ) break;
+      rc = pApi->xTokenize_v2(pFts,
+          sFinder.zDoc, nDoc, pLoc, nLoc, (void*)&sFinder, fts5SentenceFinderCb
+      );
+      if( rc!=SQLITE_OK ) break;
+      rc = pApi->xColumnSize(pFts, i, &nDocsize);
+      if( rc!=SQLITE_OK ) break;
+
+      for(ii=0; rc==SQLITE_OK && ii<nInst; ii++){
+        int ip, ic, io;
+        int iAdj;
+        int nScore;
+        int jj;
+
+        rc = pApi->xInst(pFts, ii, &ip, &ic, &io);
+        if( ic!=i ) continue;
+        if( io>nDocsize ) rc = FTS5_CORRUPT;
+        if( rc!=SQLITE_OK ) continue;
+        memset(aSeen, 0, nPhrase);
+        rc = fts5SnippetScore(pApi, pFts, nDocsize, aSeen, i,
+            io, nToken, &nScore, &iAdj
+        );
+        if( rc==SQLITE_OK && nScore>nBestScore ){
+          nBestScore = nScore;
+          iBestCol = i;
+          iBestStart = iAdj;
+          nColSize = nDocsize;
+        }
+
+        if( rc==SQLITE_OK && sFinder.nFirst && nDocsize>nToken ){
+          for(jj=0; jj<(sFinder.nFirst-1); jj++){
+            if( sFinder.aFirst[jj+1]>io ) break;
+          }
+
+          if( sFinder.aFirst[jj]<io ){
+            memset(aSeen, 0, nPhrase);
+            rc = fts5SnippetScore(pApi, pFts, nDocsize, aSeen, i,
+              sFinder.aFirst[jj], nToken, &nScore, 0
+            );
+
+            nScore += (sFinder.aFirst[jj]==0 ? 120 : 100);
+            if( rc==SQLITE_OK && nScore>nBestScore ){
+              nBestScore = nScore;
+              iBestCol = i;
+              iBestStart = sFinder.aFirst[jj];
+              nColSize = nDocsize;
+            }
+          }
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = pApi->xColumnText(pFts, iBestCol, &ctx.zIn, &ctx.nIn);
+  }
+  if( rc==SQLITE_OK && nColSize==0 ){
+    rc = pApi->xColumnSize(pFts, iBestCol, &nColSize);
+  }
+  if( ctx.zIn ){
+    const char *pLoc = 0;         /* Locale of column iBestCol */
+    int nLoc = 0;                 /* Bytes in pLoc */
+
+    if( rc==SQLITE_OK ){
+      rc = fts5CInstIterInit(pApi, pFts, iBestCol, &ctx.iter);
+    }
+
+    ctx.iRangeStart = iBestStart;
+    ctx.iRangeEnd = iBestStart + nToken - 1;
+
+    if( iBestStart>0 ){
+      fts5HighlightAppend(&rc, &ctx, zEllips, -1);
+    }
+
+    /* Advance iterator ctx.iter so that it points to the first coalesced
+    ** phrase instance at or following position iBestStart. */
+    while( ctx.iter.iStart>=0 && ctx.iter.iStart<iBestStart && rc==SQLITE_OK ){
+      rc = fts5CInstIterNext(&ctx.iter);
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = pApi->xColumnLocale(pFts, iBestCol, &pLoc, &nLoc);
+    }
+    if( rc==SQLITE_OK ){
+      rc = pApi->xTokenize_v2(
+          pFts, ctx.zIn, ctx.nIn, pLoc, nLoc, (void*)&ctx,fts5HighlightCb
+      );
+    }
+    if( ctx.bOpen ){
+      fts5HighlightAppend(&rc, &ctx, ctx.zClose, -1);
+    }
+    if( ctx.iRangeEnd>=(nColSize-1) ){
+      fts5HighlightAppend(&rc, &ctx, &ctx.zIn[ctx.iOff], ctx.nIn - ctx.iOff);
+    }else{
+      fts5HighlightAppend(&rc, &ctx, zEllips, -1);
+    }
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3_result_text(pCtx, (const char*)ctx.zOut, -1, SQLITE_TRANSIENT);
+  }else{
+    sqlite3_result_error_code(pCtx, rc);
+  }
+  sqlite3_free(ctx.zOut);
+  sqlite3_free(aSeen);
+  sqlite3_free(sFinder.aFirst);
+}
+
+/************************************************************************/
+
+/*
+** The first time the bm25() function is called for a query, an instance
+** of the following structure is allocated and populated.
+*/
+typedef struct Fts5Bm25Data Fts5Bm25Data;
+struct Fts5Bm25Data {
+  int nPhrase;                    /* Number of phrases in query */
+  double avgdl;                   /* Average number of tokens in each row */
+  double *aIDF;                   /* IDF for each phrase */
+  double *aFreq;                  /* Array used to calculate phrase freq. */
+};
+
+/*
+** Callback used by fts5Bm25GetData() to count the number of rows in the
+** table matched by each individual phrase within the query.
+*/
+static int fts5CountCb(
+  const Fts5ExtensionApi *pApi,
+  Fts5Context *pFts,
+  void *pUserData                 /* Pointer to sqlite3_int64 variable */
+){
+  sqlite3_int64 *pn = (sqlite3_int64*)pUserData;
+  UNUSED_PARAM2(pApi, pFts);
+  (*pn)++;
+  return SQLITE_OK;
+}
+
+/*
+** Set *ppData to point to the Fts5Bm25Data object for the current query.
+** If the object has not already been allocated, allocate and populate it
+** now.
+*/
+static int fts5Bm25GetData(
+  const Fts5ExtensionApi *pApi,
+  Fts5Context *pFts,
+  Fts5Bm25Data **ppData           /* OUT: bm25-data object for this query */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5Bm25Data *p;                /* Object to return */
+
+  p = (Fts5Bm25Data*)pApi->xGetAuxdata(pFts, 0);
+  if( p==0 ){
+    int nPhrase;                  /* Number of phrases in query */
+    sqlite3_int64 nRow = 0;       /* Number of rows in table */
+    sqlite3_int64 nToken = 0;     /* Number of tokens in table */
+    sqlite3_int64 nByte;          /* Bytes of space to allocate */
+    int i;
+
+    /* Allocate the Fts5Bm25Data object */
+    nPhrase = pApi->xPhraseCount(pFts);
+    nByte = sizeof(Fts5Bm25Data) + nPhrase*2*sizeof(double);
+    p = (Fts5Bm25Data*)sqlite3_malloc64(nByte);
+    if( p==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(p, 0, (size_t)nByte);
+      p->nPhrase = nPhrase;
+      p->aIDF = (double*)&p[1];
+      p->aFreq = &p->aIDF[nPhrase];
+    }
+
+    /* Calculate the average document length for this FTS5 table */
+    if( rc==SQLITE_OK ) rc = pApi->xRowCount(pFts, &nRow);
+    assert( rc!=SQLITE_OK || nRow>0 );
+    if( rc==SQLITE_OK ) rc = pApi->xColumnTotalSize(pFts, -1, &nToken);
+    if( rc==SQLITE_OK ) p->avgdl = (double)nToken  / (double)nRow;
+
+    /* Calculate an IDF for each phrase in the query */
+    for(i=0; rc==SQLITE_OK && i<nPhrase; i++){
+      sqlite3_int64 nHit = 0;
+      rc = pApi->xQueryPhrase(pFts, i, (void*)&nHit, fts5CountCb);
+      if( rc==SQLITE_OK ){
+        /* Calculate the IDF (Inverse Document Frequency) for phrase i.
+        ** This is done using the standard BM25 formula as found on wikipedia:
+        **
+        **   IDF = log( (N - nHit + 0.5) / (nHit + 0.5) )
+        **
+        ** where "N" is the total number of documents in the set and nHit
+        ** is the number that contain at least one instance of the phrase
+        ** under consideration.
+        **
+        ** The problem with this is that if (N < 2*nHit), the IDF is
+        ** negative. Which is undesirable. So the mimimum allowable IDF is
+        ** (1e-6) - roughly the same as a term that appears in just over
+        ** half of set of 5,000,000 documents.  */
+        double idf = log( (nRow - nHit + 0.5) / (nHit + 0.5) );
+        if( idf<=0.0 ) idf = 1e-6;
+        p->aIDF[i] = idf;
+      }
+    }
+
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(p);
+    }else{
+      rc = pApi->xSetAuxdata(pFts, p, sqlite3_free);
+    }
+    if( rc!=SQLITE_OK ) p = 0;
+  }
+  *ppData = p;
+  return rc;
+}
+
+/*
+** Implementation of bm25() function.
+*/
+static void fts5Bm25Function(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+){
+  const double k1 = 1.2;          /* Constant "k1" from BM25 formula */
+  const double b = 0.75;          /* Constant "b" from BM25 formula */
+  int rc;                         /* Error code */
+  double score = 0.0;             /* SQL function return value */
+  Fts5Bm25Data *pData;            /* Values allocated/calculated once only */
+  int i;                          /* Iterator variable */
+  int nInst = 0;                  /* Value returned by xInstCount() */
+  double D = 0.0;                 /* Total number of tokens in row */
+  double *aFreq = 0;              /* Array of phrase freq. for current row */
+
+  /* Calculate the phrase frequency (symbol "f(qi,D)" in the documentation)
+  ** for each phrase in the query for the current row. */
+  rc = fts5Bm25GetData(pApi, pFts, &pData);
+  if( rc==SQLITE_OK ){
+    aFreq = pData->aFreq;
+    memset(aFreq, 0, sizeof(double) * pData->nPhrase);
+    rc = pApi->xInstCount(pFts, &nInst);
+  }
+  for(i=0; rc==SQLITE_OK && i<nInst; i++){
+    int ip; int ic; int io;
+    rc = pApi->xInst(pFts, i, &ip, &ic, &io);
+    if( rc==SQLITE_OK ){
+      double w = (nVal > ic) ? sqlite3_value_double(apVal[ic]) : 1.0;
+      aFreq[ip] += w;
+    }
+  }
+
+  /* Figure out the total size of the current row in tokens. */
+  if( rc==SQLITE_OK ){
+    int nTok;
+    rc = pApi->xColumnSize(pFts, -1, &nTok);
+    D = (double)nTok;
+  }
+
+  /* Determine and return the BM25 score for the current row. Or, if an
+  ** error has occurred, throw an exception. */
+  if( rc==SQLITE_OK ){
+    for(i=0; i<pData->nPhrase; i++){
+      score += pData->aIDF[i] * (
+          ( aFreq[i] * (k1 + 1.0) ) /
+          ( aFreq[i] + k1 * (1 - b + b * D / pData->avgdl) )
+      );
+    }
+    sqlite3_result_double(pCtx, -1.0 * score);
+  }else{
+    sqlite3_result_error_code(pCtx, rc);
+  }
+}
+
+/*
+** Implementation of fts5_get_locale() function.
+*/
+static void fts5GetLocaleFunction(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+){
+  int iCol = 0;
+  int eType = 0;
+  int rc = SQLITE_OK;
+  const char *zLocale = 0;
+  int nLocale = 0;
+
+  /* xColumnLocale() must be available */
+  assert( pApi->iVersion>=4 );
+
+  if( nVal!=1 ){
+    const char *z = "wrong number of arguments to function fts5_get_locale()";
+    sqlite3_result_error(pCtx, z, -1);
+    return;
+  }
+
+  eType = sqlite3_value_numeric_type(apVal[0]);
+  if( eType!=SQLITE_INTEGER ){
+    const char *z = "non-integer argument passed to function fts5_get_locale()";
+    sqlite3_result_error(pCtx, z, -1);
+    return;
+  }
+
+  iCol = sqlite3_value_int(apVal[0]);
+  if( iCol<0 || iCol>=pApi->xColumnCount(pFts) ){
+    sqlite3_result_error_code(pCtx, SQLITE_RANGE);
+    return;
+  }
+
+  rc = pApi->xColumnLocale(pFts, iCol, &zLocale, &nLocale);
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+    return;
+  }
+
+  sqlite3_result_text(pCtx, zLocale, nLocale, SQLITE_TRANSIENT);
+}
+
+static int sqlite3Fts5AuxInit(fts5_api *pApi){
+  struct Builtin {
+    const char *zFunc;            /* Function name (nul-terminated) */
+    void *pUserData;              /* User-data pointer */
+    fts5_extension_function xFunc;/* Callback function */
+    void (*xDestroy)(void*);      /* Destructor function */
+  } aBuiltin [] = {
+    { "snippet",         0, fts5SnippetFunction,   0 },
+    { "highlight",       0, fts5HighlightFunction, 0 },
+    { "bm25",            0, fts5Bm25Function,      0 },
+    { "fts5_get_locale", 0, fts5GetLocaleFunction, 0 },
+  };
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* To iterate through builtin functions */
+
+  for(i=0; rc==SQLITE_OK && i<ArraySize(aBuiltin); i++){
+    rc = pApi->xCreateFunction(pApi,
+        aBuiltin[i].zFunc,
+        aBuiltin[i].pUserData,
+        aBuiltin[i].xFunc,
+        aBuiltin[i].xDestroy
+    );
+  }
+
+  return rc;
+}
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+
+
+/* #include "fts5Int.h" */
+
+static int sqlite3Fts5BufferSize(int *pRc, Fts5Buffer *pBuf, u32 nByte){
+  if( (u32)pBuf->nSpace<nByte ){
+    u64 nNew = pBuf->nSpace ? pBuf->nSpace : 64;
+    u8 *pNew;
+    while( nNew<nByte ){
+      nNew = nNew * 2;
+    }
+    pNew = sqlite3_realloc64(pBuf->p, nNew);
+    if( pNew==0 ){
+      *pRc = SQLITE_NOMEM;
+      return 1;
+    }else{
+      pBuf->nSpace = (int)nNew;
+      pBuf->p = pNew;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** Encode value iVal as an SQLite varint and append it to the buffer object
+** pBuf. If an OOM error occurs, set the error code in p.
+*/
+static void sqlite3Fts5BufferAppendVarint(int *pRc, Fts5Buffer *pBuf, i64 iVal){
+  if( fts5BufferGrow(pRc, pBuf, 9) ) return;
+  pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], iVal);
+}
+
+static void sqlite3Fts5Put32(u8 *aBuf, int iVal){
+  aBuf[0] = (iVal>>24) & 0x00FF;
+  aBuf[1] = (iVal>>16) & 0x00FF;
+  aBuf[2] = (iVal>> 8) & 0x00FF;
+  aBuf[3] = (iVal>> 0) & 0x00FF;
+}
+
+static int sqlite3Fts5Get32(const u8 *aBuf){
+  return (int)((((u32)aBuf[0])<<24) + (aBuf[1]<<16) + (aBuf[2]<<8) + aBuf[3]);
+}
+
+/*
+** Append buffer nData/pData to buffer pBuf. If an OOM error occurs, set
+** the error code in p. If an error has already occurred when this function
+** is called, it is a no-op.
+*/
+static void sqlite3Fts5BufferAppendBlob(
+  int *pRc,
+  Fts5Buffer *pBuf,
+  u32 nData,
+  const u8 *pData
+){
+  if( nData ){
+    if( fts5BufferGrow(pRc, pBuf, nData) ) return;
+    assert( pBuf->p!=0 );
+    memcpy(&pBuf->p[pBuf->n], pData, nData);
+    pBuf->n += nData;
+  }
+}
+
+/*
+** Append the nul-terminated string zStr to the buffer pBuf. This function
+** ensures that the byte following the buffer data is set to 0x00, even
+** though this byte is not included in the pBuf->n count.
+*/
+static void sqlite3Fts5BufferAppendString(
+  int *pRc,
+  Fts5Buffer *pBuf,
+  const char *zStr
+){
+  int nStr = (int)strlen(zStr);
+  sqlite3Fts5BufferAppendBlob(pRc, pBuf, nStr+1, (const u8*)zStr);
+  pBuf->n--;
+}
+
+/*
+** Argument zFmt is a printf() style format string. This function performs
+** the printf() style processing, then appends the results to buffer pBuf.
+**
+** Like sqlite3Fts5BufferAppendString(), this function ensures that the byte
+** following the buffer data is set to 0x00, even though this byte is not
+** included in the pBuf->n count.
+*/
+static void sqlite3Fts5BufferAppendPrintf(
+  int *pRc,
+  Fts5Buffer *pBuf,
+  char *zFmt, ...
+){
+  if( *pRc==SQLITE_OK ){
+    char *zTmp;
+    va_list ap;
+    va_start(ap, zFmt);
+    zTmp = sqlite3_vmprintf(zFmt, ap);
+    va_end(ap);
+
+    if( zTmp==0 ){
+      *pRc = SQLITE_NOMEM;
+    }else{
+      sqlite3Fts5BufferAppendString(pRc, pBuf, zTmp);
+      sqlite3_free(zTmp);
+    }
+  }
+}
+
+static char *sqlite3Fts5Mprintf(int *pRc, const char *zFmt, ...){
+  char *zRet = 0;
+  if( *pRc==SQLITE_OK ){
+    va_list ap;
+    va_start(ap, zFmt);
+    zRet = sqlite3_vmprintf(zFmt, ap);
+    va_end(ap);
+    if( zRet==0 ){
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+  return zRet;
+}
+
+
+/*
+** Free any buffer allocated by pBuf. Zero the structure before returning.
+*/
+static void sqlite3Fts5BufferFree(Fts5Buffer *pBuf){
+  sqlite3_free(pBuf->p);
+  memset(pBuf, 0, sizeof(Fts5Buffer));
+}
+
+/*
+** Zero the contents of the buffer object. But do not free the associated
+** memory allocation.
+*/
+static void sqlite3Fts5BufferZero(Fts5Buffer *pBuf){
+  pBuf->n = 0;
+}
+
+/*
+** Set the buffer to contain nData/pData. If an OOM error occurs, leave an
+** the error code in p. If an error has already occurred when this function
+** is called, it is a no-op.
+*/
+static void sqlite3Fts5BufferSet(
+  int *pRc,
+  Fts5Buffer *pBuf,
+  int nData,
+  const u8 *pData
+){
+  pBuf->n = 0;
+  sqlite3Fts5BufferAppendBlob(pRc, pBuf, nData, pData);
+}
+
+static int sqlite3Fts5PoslistNext64(
+  const u8 *a, int n,             /* Buffer containing poslist */
+  int *pi,                        /* IN/OUT: Offset within a[] */
+  i64 *piOff                      /* IN/OUT: Current offset */
+){
+  int i = *pi;
+  assert( a!=0 || i==0 );
+  if( i>=n ){
+    /* EOF */
+    *piOff = -1;
+    return 1;
+  }else{
+    i64 iOff = *piOff;
+    u32 iVal;
+    assert( a!=0 );
+    fts5FastGetVarint32(a, i, iVal);
+    if( iVal<=1 ){
+      if( iVal==0 ){
+        *pi = i;
+        return 0;
+      }
+      fts5FastGetVarint32(a, i, iVal);
+      iOff = ((i64)iVal) << 32;
+      assert( iOff>=0 );
+      fts5FastGetVarint32(a, i, iVal);
+      if( iVal<2 ){
+        /* This is a corrupt record. So stop parsing it here. */
+        *piOff = -1;
+        return 1;
+      }
+      *piOff = iOff + ((iVal-2) & 0x7FFFFFFF);
+    }else{
+      *piOff = (iOff & (i64)0x7FFFFFFF<<32)+((iOff + (iVal-2)) & 0x7FFFFFFF);
+    }
+    *pi = i;
+    assert_nc( *piOff>=iOff );
+    return 0;
+  }
+}
+
+
+/*
+** Advance the iterator object passed as the only argument. Return true
+** if the iterator reaches EOF, or false otherwise.
+*/
+static int sqlite3Fts5PoslistReaderNext(Fts5PoslistReader *pIter){
+  if( sqlite3Fts5PoslistNext64(pIter->a, pIter->n, &pIter->i, &pIter->iPos) ){
+    pIter->bEof = 1;
+  }
+  return pIter->bEof;
+}
+
+static int sqlite3Fts5PoslistReaderInit(
+  const u8 *a, int n,             /* Poslist buffer to iterate through */
+  Fts5PoslistReader *pIter        /* Iterator object to initialize */
+){
+  memset(pIter, 0, sizeof(*pIter));
+  pIter->a = a;
+  pIter->n = n;
+  sqlite3Fts5PoslistReaderNext(pIter);
+  return pIter->bEof;
+}
+
+/*
+** Append position iPos to the position list being accumulated in buffer
+** pBuf, which must be already be large enough to hold the new data.
+** The previous position written to this list is *piPrev. *piPrev is set
+** to iPos before returning.
+*/
+static void sqlite3Fts5PoslistSafeAppend(
+  Fts5Buffer *pBuf,
+  i64 *piPrev,
+  i64 iPos
+){
+  if( iPos>=*piPrev ){
+    static const i64 colmask = ((i64)(0x7FFFFFFF)) << 32;
+    if( (iPos & colmask) != (*piPrev & colmask) ){
+      pBuf->p[pBuf->n++] = 1;
+      pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], (iPos>>32));
+      *piPrev = (iPos & colmask);
+    }
+    pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], (iPos-*piPrev)+2);
+    *piPrev = iPos;
+  }
+}
+
+static int sqlite3Fts5PoslistWriterAppend(
+  Fts5Buffer *pBuf,
+  Fts5PoslistWriter *pWriter,
+  i64 iPos
+){
+  int rc = 0;   /* Initialized only to suppress erroneous warning from Clang */
+  if( fts5BufferGrow(&rc, pBuf, 5+5+5) ) return rc;
+  sqlite3Fts5PoslistSafeAppend(pBuf, &pWriter->iPrev, iPos);
+  return SQLITE_OK;
+}
+
+static void *sqlite3Fts5MallocZero(int *pRc, sqlite3_int64 nByte){
+  void *pRet = 0;
+  if( *pRc==SQLITE_OK ){
+    pRet = sqlite3_malloc64(nByte);
+    if( pRet==0 ){
+      if( nByte>0 ) *pRc = SQLITE_NOMEM;
+    }else{
+      memset(pRet, 0, (size_t)nByte);
+    }
+  }
+  return pRet;
+}
+
+/*
+** Return a nul-terminated copy of the string indicated by pIn. If nIn
+** is non-negative, then it is the length of the string in bytes. Otherwise,
+** the length of the string is determined using strlen().
+**
+** It is the responsibility of the caller to eventually free the returned
+** buffer using sqlite3_free(). If an OOM error occurs, NULL is returned.
+*/
+static char *sqlite3Fts5Strndup(int *pRc, const char *pIn, int nIn){
+  char *zRet = 0;
+  if( *pRc==SQLITE_OK ){
+    if( nIn<0 ){
+      nIn = (int)strlen(pIn);
+    }
+    zRet = (char*)sqlite3_malloc(nIn+1);
+    if( zRet ){
+      memcpy(zRet, pIn, nIn);
+      zRet[nIn] = '\0';
+    }else{
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+  return zRet;
+}
+
+
+/*
+** Return true if character 't' may be part of an FTS5 bareword, or false
+** otherwise. Characters that may be part of barewords:
+**
+**   * All non-ASCII characters,
+**   * The 52 upper and lower case ASCII characters, and
+**   * The 10 integer ASCII characters.
+**   * The underscore character "_" (0x5F).
+**   * The unicode "subsitute" character (0x1A).
+*/
+static int sqlite3Fts5IsBareword(char t){
+  u8 aBareword[128] = {
+    0, 0, 0, 0, 0, 0, 0, 0,    0, 0, 0, 0, 0, 0, 0, 0,   /* 0x00 .. 0x0F */
+    0, 0, 0, 0, 0, 0, 0, 0,    0, 0, 1, 0, 0, 0, 0, 0,   /* 0x10 .. 0x1F */
+    0, 0, 0, 0, 0, 0, 0, 0,    0, 0, 0, 0, 0, 0, 0, 0,   /* 0x20 .. 0x2F */
+    1, 1, 1, 1, 1, 1, 1, 1,    1, 1, 0, 0, 0, 0, 0, 0,   /* 0x30 .. 0x3F */
+    0, 1, 1, 1, 1, 1, 1, 1,    1, 1, 1, 1, 1, 1, 1, 1,   /* 0x40 .. 0x4F */
+    1, 1, 1, 1, 1, 1, 1, 1,    1, 1, 1, 0, 0, 0, 0, 1,   /* 0x50 .. 0x5F */
+    0, 1, 1, 1, 1, 1, 1, 1,    1, 1, 1, 1, 1, 1, 1, 1,   /* 0x60 .. 0x6F */
+    1, 1, 1, 1, 1, 1, 1, 1,    1, 1, 1, 0, 0, 0, 0, 0    /* 0x70 .. 0x7F */
+  };
+
+  return (t & 0x80) || aBareword[(int)t];
+}
+
+
+/*************************************************************************
+*/
+typedef struct Fts5TermsetEntry Fts5TermsetEntry;
+struct Fts5TermsetEntry {
+  char *pTerm;
+  int nTerm;
+  int iIdx;                       /* Index (main or aPrefix[] entry) */
+  Fts5TermsetEntry *pNext;
+};
+
+struct Fts5Termset {
+  Fts5TermsetEntry *apHash[512];
+};
+
+static int sqlite3Fts5TermsetNew(Fts5Termset **pp){
+  int rc = SQLITE_OK;
+  *pp = sqlite3Fts5MallocZero(&rc, sizeof(Fts5Termset));
+  return rc;
+}
+
+static int sqlite3Fts5TermsetAdd(
+  Fts5Termset *p,
+  int iIdx,
+  const char *pTerm, int nTerm,
+  int *pbPresent
+){
+  int rc = SQLITE_OK;
+  *pbPresent = 0;
+  if( p ){
+    int i;
+    u32 hash = 13;
+    Fts5TermsetEntry *pEntry;
+
+    /* Calculate a hash value for this term. This is the same hash checksum
+    ** used by the fts5_hash.c module. This is not important for correct
+    ** operation of the module, but is necessary to ensure that some tests
+    ** designed to produce hash table collisions really do work.  */
+    for(i=nTerm-1; i>=0; i--){
+      hash = (hash << 3) ^ hash ^ pTerm[i];
+    }
+    hash = (hash << 3) ^ hash ^ iIdx;
+    hash = hash % ArraySize(p->apHash);
+
+    for(pEntry=p->apHash[hash]; pEntry; pEntry=pEntry->pNext){
+      if( pEntry->iIdx==iIdx
+          && pEntry->nTerm==nTerm
+          && memcmp(pEntry->pTerm, pTerm, nTerm)==0
+      ){
+        *pbPresent = 1;
+        break;
+      }
+    }
+
+    if( pEntry==0 ){
+      pEntry = sqlite3Fts5MallocZero(&rc, sizeof(Fts5TermsetEntry) + nTerm);
+      if( pEntry ){
+        pEntry->pTerm = (char*)&pEntry[1];
+        pEntry->nTerm = nTerm;
+        pEntry->iIdx = iIdx;
+        memcpy(pEntry->pTerm, pTerm, nTerm);
+        pEntry->pNext = p->apHash[hash];
+        p->apHash[hash] = pEntry;
+      }
+    }
+  }
+
+  return rc;
+}
+
+static void sqlite3Fts5TermsetFree(Fts5Termset *p){
+  if( p ){
+    u32 i;
+    for(i=0; i<ArraySize(p->apHash); i++){
+      Fts5TermsetEntry *pEntry = p->apHash[i];
+      while( pEntry ){
+        Fts5TermsetEntry *pDel = pEntry;
+        pEntry = pEntry->pNext;
+        sqlite3_free(pDel);
+      }
+    }
+    sqlite3_free(p);
+  }
+}
+
+/*
+** 2014 Jun 09
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is an SQLite module implementing full-text search.
+*/
+
+
+/* #include "fts5Int.h" */
+
+#define FTS5_DEFAULT_PAGE_SIZE   4050
+#define FTS5_DEFAULT_AUTOMERGE      4
+#define FTS5_DEFAULT_USERMERGE      4
+#define FTS5_DEFAULT_CRISISMERGE   16
+#define FTS5_DEFAULT_HASHSIZE    (1024*1024)
+
+#define FTS5_DEFAULT_DELETE_AUTOMERGE 10      /* default 10% */
+
+/* Maximum allowed page size */
+#define FTS5_MAX_PAGE_SIZE (64*1024)
+
+static int fts5_iswhitespace(char x){
+  return (x==' ');
+}
+
+static int fts5_isopenquote(char x){
+  return (x=='"' || x=='\'' || x=='[' || x=='`');
+}
+
+/*
+** Argument pIn points to a character that is part of a nul-terminated
+** string. Return a pointer to the first character following *pIn in
+** the string that is not a white-space character.
+*/
+static const char *fts5ConfigSkipWhitespace(const char *pIn){
+  const char *p = pIn;
+  if( p ){
+    while( fts5_iswhitespace(*p) ){ p++; }
+  }
+  return p;
+}
+
+/*
+** Argument pIn points to a character that is part of a nul-terminated
+** string. Return a pointer to the first character following *pIn in
+** the string that is not a "bareword" character.
+*/
+static const char *fts5ConfigSkipBareword(const char *pIn){
+  const char *p = pIn;
+  while ( sqlite3Fts5IsBareword(*p) ) p++;
+  if( p==pIn ) p = 0;
+  return p;
+}
+
+static int fts5_isdigit(char a){
+  return (a>='0' && a<='9');
+}
+
+
+
+static const char *fts5ConfigSkipLiteral(const char *pIn){
+  const char *p = pIn;
+  switch( *p ){
+    case 'n': case 'N':
+      if( sqlite3_strnicmp("null", p, 4)==0 ){
+        p = &p[4];
+      }else{
+        p = 0;
+      }
+      break;
+
+    case 'x': case 'X':
+      p++;
+      if( *p=='\'' ){
+        p++;
+        while( (*p>='a' && *p<='f')
+            || (*p>='A' && *p<='F')
+            || (*p>='0' && *p<='9')
+            ){
+          p++;
+        }
+        if( *p=='\'' && 0==((p-pIn)%2) ){
+          p++;
+        }else{
+          p = 0;
+        }
+      }else{
+        p = 0;
+      }
+      break;
+
+    case '\'':
+      p++;
+      while( p ){
+        if( *p=='\'' ){
+          p++;
+          if( *p!='\'' ) break;
+        }
+        p++;
+        if( *p==0 ) p = 0;
+      }
+      break;
+
+    default:
+      /* maybe a number */
+      if( *p=='+' || *p=='-' ) p++;
+      while( fts5_isdigit(*p) ) p++;
+
+      /* At this point, if the literal was an integer, the parse is
+      ** finished. Or, if it is a floating point value, it may continue
+      ** with either a decimal point or an 'E' character. */
+      if( *p=='.' && fts5_isdigit(p[1]) ){
+        p += 2;
+        while( fts5_isdigit(*p) ) p++;
+      }
+      if( p==pIn ) p = 0;
+
+      break;
+  }
+
+  return p;
+}
+
+/*
+** The first character of the string pointed to by argument z is guaranteed
+** to be an open-quote character (see function fts5_isopenquote()).
+**
+** This function searches for the corresponding close-quote character within
+** the string and, if found, dequotes the string in place and adds a new
+** nul-terminator byte.
+**
+** If the close-quote is found, the value returned is the byte offset of
+** the character immediately following it. Or, if the close-quote is not
+** found, -1 is returned. If -1 is returned, the buffer is left in an
+** undefined state.
+*/
+static int fts5Dequote(char *z){
+  char q;
+  int iIn = 1;
+  int iOut = 0;
+  q = z[0];
+
+  /* Set stack variable q to the close-quote character */
+  assert( q=='[' || q=='\'' || q=='"' || q=='`' );
+  if( q=='[' ) q = ']';
+
+  while( z[iIn] ){
+    if( z[iIn]==q ){
+      if( z[iIn+1]!=q ){
+        /* Character iIn was the close quote. */
+        iIn++;
+        break;
+      }else{
+        /* Character iIn and iIn+1 form an escaped quote character. Skip
+        ** the input cursor past both and copy a single quote character
+        ** to the output buffer. */
+        iIn += 2;
+        z[iOut++] = q;
+      }
+    }else{
+      z[iOut++] = z[iIn++];
+    }
+  }
+
+  z[iOut] = '\0';
+  return iIn;
+}
+
+/*
+** Convert an SQL-style quoted string into a normal string by removing
+** the quote characters.  The conversion is done in-place.  If the
+** input does not begin with a quote character, then this routine
+** is a no-op.
+**
+** Examples:
+**
+**     "abc"   becomes   abc
+**     'xyz'   becomes   xyz
+**     [pqr]   becomes   pqr
+**     `mno`   becomes   mno
+*/
+static void sqlite3Fts5Dequote(char *z){
+  char quote;                     /* Quote character (if any ) */
+
+  assert( 0==fts5_iswhitespace(z[0]) );
+  quote = z[0];
+  if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){
+    fts5Dequote(z);
+  }
+}
+
+
+struct Fts5Enum {
+  const char *zName;
+  int eVal;
+};
+typedef struct Fts5Enum Fts5Enum;
+
+static int fts5ConfigSetEnum(
+  const Fts5Enum *aEnum,
+  const char *zEnum,
+  int *peVal
+){
+  int nEnum = (int)strlen(zEnum);
+  int i;
+  int iVal = -1;
+
+  for(i=0; aEnum[i].zName; i++){
+    if( sqlite3_strnicmp(aEnum[i].zName, zEnum, nEnum)==0 ){
+      if( iVal>=0 ) return SQLITE_ERROR;
+      iVal = aEnum[i].eVal;
+    }
+  }
+
+  *peVal = iVal;
+  return iVal<0 ? SQLITE_ERROR : SQLITE_OK;
+}
+
+/*
+** Parse a "special" CREATE VIRTUAL TABLE directive and update
+** configuration object pConfig as appropriate.
+**
+** If successful, object pConfig is updated and SQLITE_OK returned. If
+** an error occurs, an SQLite error code is returned and an error message
+** may be left in *pzErr. It is the responsibility of the caller to
+** eventually free any such error message using sqlite3_free().
+*/
+static int fts5ConfigParseSpecial(
+  Fts5Config *pConfig,            /* Configuration object to update */
+  const char *zCmd,               /* Special command to parse */
+  const char *zArg,               /* Argument to parse */
+  char **pzErr                    /* OUT: Error message */
+){
+  int rc = SQLITE_OK;
+  int nCmd = (int)strlen(zCmd);
+
+  if( sqlite3_strnicmp("prefix", zCmd, nCmd)==0 ){
+    const int nByte = sizeof(int) * FTS5_MAX_PREFIX_INDEXES;
+    const char *p;
+    int bFirst = 1;
+    if( pConfig->aPrefix==0 ){
+      pConfig->aPrefix = sqlite3Fts5MallocZero(&rc, nByte);
+      if( rc ) return rc;
+    }
+
+    p = zArg;
+    while( 1 ){
+      int nPre = 0;
+
+      while( p[0]==' ' ) p++;
+      if( bFirst==0 && p[0]==',' ){
+        p++;
+        while( p[0]==' ' ) p++;
+      }else if( p[0]=='\0' ){
+        break;
+      }
+      if( p[0]<'0' || p[0]>'9' ){
+        *pzErr = sqlite3_mprintf("malformed prefix=... directive");
+        rc = SQLITE_ERROR;
+        break;
+      }
+
+      if( pConfig->nPrefix==FTS5_MAX_PREFIX_INDEXES ){
+        *pzErr = sqlite3_mprintf(
+            "too many prefix indexes (max %d)", FTS5_MAX_PREFIX_INDEXES
+        );
+        rc = SQLITE_ERROR;
+        break;
+      }
+
+      while( p[0]>='0' && p[0]<='9' && nPre<1000 ){
+        nPre = nPre*10 + (p[0] - '0');
+        p++;
+      }
+
+      if( nPre<=0 || nPre>=1000 ){
+        *pzErr = sqlite3_mprintf("prefix length out of range (max 999)");
+        rc = SQLITE_ERROR;
+        break;
+      }
+
+      pConfig->aPrefix[pConfig->nPrefix] = nPre;
+      pConfig->nPrefix++;
+      bFirst = 0;
+    }
+    assert( pConfig->nPrefix<=FTS5_MAX_PREFIX_INDEXES );
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("tokenize", zCmd, nCmd)==0 ){
+    const char *p = (const char*)zArg;
+    sqlite3_int64 nArg = strlen(zArg) + 1;
+    char **azArg = sqlite3Fts5MallocZero(&rc, (sizeof(char*) + 2) * nArg);
+
+    if( azArg ){
+      char *pSpace = (char*)&azArg[nArg];
+      if( pConfig->t.azArg ){
+        *pzErr = sqlite3_mprintf("multiple tokenize=... directives");
+        rc = SQLITE_ERROR;
+      }else{
+        for(nArg=0; p && *p; nArg++){
+          const char *p2 = fts5ConfigSkipWhitespace(p);
+          if( *p2=='\'' ){
+            p = fts5ConfigSkipLiteral(p2);
+          }else{
+            p = fts5ConfigSkipBareword(p2);
+          }
+          if( p ){
+            memcpy(pSpace, p2, p-p2);
+            azArg[nArg] = pSpace;
+            sqlite3Fts5Dequote(pSpace);
+            pSpace += (p - p2) + 1;
+            p = fts5ConfigSkipWhitespace(p);
+          }
+        }
+        if( p==0 ){
+          *pzErr = sqlite3_mprintf("parse error in tokenize directive");
+          rc = SQLITE_ERROR;
+        }else{
+          pConfig->t.azArg = (const char**)azArg;
+          pConfig->t.nArg = nArg;
+          azArg = 0;
+        }
+      }
+    }
+    sqlite3_free(azArg);
+
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("content", zCmd, nCmd)==0 ){
+    if( pConfig->eContent!=FTS5_CONTENT_NORMAL ){
+      *pzErr = sqlite3_mprintf("multiple content=... directives");
+      rc = SQLITE_ERROR;
+    }else{
+      if( zArg[0] ){
+        pConfig->eContent = FTS5_CONTENT_EXTERNAL;
+        pConfig->zContent = sqlite3Fts5Mprintf(&rc, "%Q.%Q", pConfig->zDb,zArg);
+      }else{
+        pConfig->eContent = FTS5_CONTENT_NONE;
+      }
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("contentless_delete", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed contentless_delete=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bContentlessDelete = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("contentless_unindexed", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed contentless_delete=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bContentlessUnindexed = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("content_rowid", zCmd, nCmd)==0 ){
+    if( pConfig->zContentRowid ){
+      *pzErr = sqlite3_mprintf("multiple content_rowid=... directives");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->zContentRowid = sqlite3Fts5Strndup(&rc, zArg, -1);
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("columnsize", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed columnsize=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bColumnsize = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("locale", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed locale=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bLocale = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("detail", zCmd, nCmd)==0 ){
+    const Fts5Enum aDetail[] = {
+      { "none", FTS5_DETAIL_NONE },
+      { "full", FTS5_DETAIL_FULL },
+      { "columns", FTS5_DETAIL_COLUMNS },
+      { 0, 0 }
+    };
+
+    if( (rc = fts5ConfigSetEnum(aDetail, zArg, &pConfig->eDetail)) ){
+      *pzErr = sqlite3_mprintf("malformed detail=... directive");
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("tokendata", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed tokendata=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bTokendata = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  *pzErr = sqlite3_mprintf("unrecognized option: \"%.*s\"", nCmd, zCmd);
+  return SQLITE_ERROR;
+}
+
+/*
+** Gobble up the first bareword or quoted word from the input buffer zIn.
+** Return a pointer to the character immediately following the last in
+** the gobbled word if successful, or a NULL pointer otherwise (failed
+** to find close-quote character).
+**
+** Before returning, set pzOut to point to a new buffer containing a
+** nul-terminated, dequoted copy of the gobbled word. If the word was
+** quoted, *pbQuoted is also set to 1 before returning.
+**
+** If *pRc is other than SQLITE_OK when this function is called, it is
+** a no-op (NULL is returned). Otherwise, if an OOM occurs within this
+** function, *pRc is set to SQLITE_NOMEM before returning. *pRc is *not*
+** set if a parse error (failed to find close quote) occurs.
+*/
+static const char *fts5ConfigGobbleWord(
+  int *pRc,                       /* IN/OUT: Error code */
+  const char *zIn,                /* Buffer to gobble string/bareword from */
+  char **pzOut,                   /* OUT: malloc'd buffer containing str/bw */
+  int *pbQuoted                   /* OUT: Set to true if dequoting required */
+){
+  const char *zRet = 0;
+
+  sqlite3_int64 nIn = strlen(zIn);
+  char *zOut = sqlite3_malloc64(nIn+1);
+
+  assert( *pRc==SQLITE_OK );
+  *pbQuoted = 0;
+  *pzOut = 0;
+
+  if( zOut==0 ){
+    *pRc = SQLITE_NOMEM;
+  }else{
+    memcpy(zOut, zIn, (size_t)(nIn+1));
+    if( fts5_isopenquote(zOut[0]) ){
+      int ii = fts5Dequote(zOut);
+      zRet = &zIn[ii];
+      *pbQuoted = 1;
+    }else{
+      zRet = fts5ConfigSkipBareword(zIn);
+      if( zRet ){
+        zOut[zRet-zIn] = '\0';
+      }
+    }
+  }
+
+  if( zRet==0 ){
+    sqlite3_free(zOut);
+  }else{
+    *pzOut = zOut;
+  }
+
+  return zRet;
+}
+
+static int fts5ConfigParseColumn(
+  Fts5Config *p,
+  char *zCol,
+  char *zArg,
+  char **pzErr,
+  int *pbUnindexed
+){
+  int rc = SQLITE_OK;
+  if( 0==sqlite3_stricmp(zCol, FTS5_RANK_NAME)
+   || 0==sqlite3_stricmp(zCol, FTS5_ROWID_NAME)
+  ){
+    *pzErr = sqlite3_mprintf("reserved fts5 column name: %s", zCol);
+    rc = SQLITE_ERROR;
+  }else if( zArg ){
+    if( 0==sqlite3_stricmp(zArg, "unindexed") ){
+      p->abUnindexed[p->nCol] = 1;
+      *pbUnindexed = 1;
+    }else{
+      *pzErr = sqlite3_mprintf("unrecognized column option: %s", zArg);
+      rc = SQLITE_ERROR;
+    }
+  }
+
+  p->azCol[p->nCol++] = zCol;
+  return rc;
+}
+
+/*
+** Populate the Fts5Config.zContentExprlist string.
+*/
+static int fts5ConfigMakeExprlist(Fts5Config *p){
+  int i;
+  int rc = SQLITE_OK;
+  Fts5Buffer buf = {0, 0, 0};
+
+  sqlite3Fts5BufferAppendPrintf(&rc, &buf, "T.%Q", p->zContentRowid);
+  if( p->eContent!=FTS5_CONTENT_NONE ){
+    assert( p->eContent==FTS5_CONTENT_EXTERNAL
+         || p->eContent==FTS5_CONTENT_NORMAL
+         || p->eContent==FTS5_CONTENT_UNINDEXED
+    );
+    for(i=0; i<p->nCol; i++){
+      if( p->eContent==FTS5_CONTENT_EXTERNAL ){
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", T.%Q", p->azCol[i]);
+      }else if( p->eContent==FTS5_CONTENT_NORMAL || p->abUnindexed[i] ){
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", T.c%d", i);
+      }else{
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", NULL");
+      }
+    }
+  }
+  if( p->eContent==FTS5_CONTENT_NORMAL && p->bLocale ){
+    for(i=0; i<p->nCol; i++){
+      if( p->abUnindexed[i]==0 ){
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", T.l%d", i);
+      }else{
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", NULL");
+      }
+    }
+  }
+
+  assert( p->zContentExprlist==0 );
+  p->zContentExprlist = (char*)buf.p;
+  return rc;
+}
+
+/*
+** Arguments nArg/azArg contain the string arguments passed to the xCreate
+** or xConnect method of the virtual table. This function attempts to
+** allocate an instance of Fts5Config containing the results of parsing
+** those arguments.
+**
+** If successful, SQLITE_OK is returned and *ppOut is set to point to the
+** new Fts5Config object. If an error occurs, an SQLite error code is
+** returned, *ppOut is set to NULL and an error message may be left in
+** *pzErr. It is the responsibility of the caller to eventually free any
+** such error message using sqlite3_free().
+*/
+static int sqlite3Fts5ConfigParse(
+  Fts5Global *pGlobal,
+  sqlite3 *db,
+  int nArg,                       /* Number of arguments */
+  const char **azArg,             /* Array of nArg CREATE VIRTUAL TABLE args */
+  Fts5Config **ppOut,             /* OUT: Results of parse */
+  char **pzErr                    /* OUT: Error message */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5Config *pRet;               /* New object to return */
+  int i;
+  sqlite3_int64 nByte;
+  int bUnindexed = 0;             /* True if there are one or more UNINDEXED */
+
+  *ppOut = pRet = (Fts5Config*)sqlite3_malloc(sizeof(Fts5Config));
+  if( pRet==0 ) return SQLITE_NOMEM;
+  memset(pRet, 0, sizeof(Fts5Config));
+  pRet->pGlobal = pGlobal;
+  pRet->db = db;
+  pRet->iCookie = -1;
+
+  nByte = nArg * (sizeof(char*) + sizeof(u8));
+  pRet->azCol = (char**)sqlite3Fts5MallocZero(&rc, nByte);
+  pRet->abUnindexed = pRet->azCol ? (u8*)&pRet->azCol[nArg] : 0;
+  pRet->zDb = sqlite3Fts5Strndup(&rc, azArg[1], -1);
+  pRet->zName = sqlite3Fts5Strndup(&rc, azArg[2], -1);
+  pRet->bColumnsize = 1;
+  pRet->eDetail = FTS5_DETAIL_FULL;
+#ifdef SQLITE_DEBUG
+  pRet->bPrefixIndex = 1;
+#endif
+  if( rc==SQLITE_OK && sqlite3_stricmp(pRet->zName, FTS5_RANK_NAME)==0 ){
+    *pzErr = sqlite3_mprintf("reserved fts5 table name: %s", pRet->zName);
+    rc = SQLITE_ERROR;
+  }
+
+  assert( (pRet->abUnindexed && pRet->azCol) || rc!=SQLITE_OK );
+  for(i=3; rc==SQLITE_OK && i<nArg; i++){
+    const char *zOrig = azArg[i];
+    const char *z;
+    char *zOne = 0;
+    char *zTwo = 0;
+    int bOption = 0;
+    int bMustBeCol = 0;
+
+    z = fts5ConfigGobbleWord(&rc, zOrig, &zOne, &bMustBeCol);
+    z = fts5ConfigSkipWhitespace(z);
+    if( z && *z=='=' ){
+      bOption = 1;
+      assert( zOne!=0 );
+      z++;
+      if( bMustBeCol ) z = 0;
+    }
+    z = fts5ConfigSkipWhitespace(z);
+    if( z && z[0] ){
+      int bDummy;
+      z = fts5ConfigGobbleWord(&rc, z, &zTwo, &bDummy);
+      if( z && z[0] ) z = 0;
+    }
+
+    if( rc==SQLITE_OK ){
+      if( z==0 ){
+        *pzErr = sqlite3_mprintf("parse error in \"%s\"", zOrig);
+        rc = SQLITE_ERROR;
+      }else{
+        if( bOption ){
+          rc = fts5ConfigParseSpecial(pRet,
+            ALWAYS(zOne)?zOne:"",
+            zTwo?zTwo:"",
+            pzErr
+          );
+        }else{
+          rc = fts5ConfigParseColumn(pRet, zOne, zTwo, pzErr, &bUnindexed);
+          zOne = 0;
+        }
+      }
+    }
+
+    sqlite3_free(zOne);
+    sqlite3_free(zTwo);
+  }
+
+  /* We only allow contentless_delete=1 if the table is indeed contentless. */
+  if( rc==SQLITE_OK
+   && pRet->bContentlessDelete
+   && pRet->eContent!=FTS5_CONTENT_NONE
+  ){
+    *pzErr = sqlite3_mprintf(
+        "contentless_delete=1 requires a contentless table"
+    );
+    rc = SQLITE_ERROR;
+  }
+
+  /* We only allow contentless_delete=1 if columnsize=0 is not present.
+  **
+  ** This restriction may be removed at some point.
+  */
+  if( rc==SQLITE_OK && pRet->bContentlessDelete && pRet->bColumnsize==0 ){
+    *pzErr = sqlite3_mprintf(
+        "contentless_delete=1 is incompatible with columnsize=0"
+    );
+    rc = SQLITE_ERROR;
+  }
+
+  /* We only allow contentless_unindexed=1 if the table is actually a
+  ** contentless one.
+  */
+  if( rc==SQLITE_OK
+   && pRet->bContentlessUnindexed
+   && pRet->eContent!=FTS5_CONTENT_NONE
+  ){
+    *pzErr = sqlite3_mprintf(
+        "contentless_unindexed=1 requires a contentless table"
+    );
+    rc = SQLITE_ERROR;
+  }
+
+  /* If no zContent option was specified, fill in the default values. */
+  if( rc==SQLITE_OK && pRet->zContent==0 ){
+    const char *zTail = 0;
+    assert( pRet->eContent==FTS5_CONTENT_NORMAL
+         || pRet->eContent==FTS5_CONTENT_NONE
+    );
+    if( pRet->eContent==FTS5_CONTENT_NORMAL ){
+      zTail = "content";
+    }else if( bUnindexed && pRet->bContentlessUnindexed ){
+      pRet->eContent = FTS5_CONTENT_UNINDEXED;
+      zTail = "content";
+    }else if( pRet->bColumnsize ){
+      zTail = "docsize";
+    }
+
+    if( zTail ){
+      pRet->zContent = sqlite3Fts5Mprintf(
+          &rc, "%Q.'%q_%s'", pRet->zDb, pRet->zName, zTail
+      );
+    }
+  }
+
+  if( rc==SQLITE_OK && pRet->zContentRowid==0 ){
+    pRet->zContentRowid = sqlite3Fts5Strndup(&rc, "rowid", -1);
+  }
+
+  /* Formulate the zContentExprlist text */
+  if( rc==SQLITE_OK ){
+    rc = fts5ConfigMakeExprlist(pRet);
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3Fts5ConfigFree(pRet);
+    *ppOut = 0;
+  }
+  return rc;
+}
+
+/*
+** Free the configuration object passed as the only argument.
+*/
+static void sqlite3Fts5ConfigFree(Fts5Config *pConfig){
+  if( pConfig ){
+    int i;
+    if( pConfig->t.pTok ){
+      if( pConfig->t.pApi1 ){
+        pConfig->t.pApi1->xDelete(pConfig->t.pTok);
+      }else{
+        pConfig->t.pApi2->xDelete(pConfig->t.pTok);
+      }
+    }
+    sqlite3_free((char*)pConfig->t.azArg);
+    sqlite3_free(pConfig->zDb);
+    sqlite3_free(pConfig->zName);
+    for(i=0; i<pConfig->nCol; i++){
+      sqlite3_free(pConfig->azCol[i]);
+    }
+    sqlite3_free(pConfig->azCol);
+    sqlite3_free(pConfig->aPrefix);
+    sqlite3_free(pConfig->zRank);
+    sqlite3_free(pConfig->zRankArgs);
+    sqlite3_free(pConfig->zContent);
+    sqlite3_free(pConfig->zContentRowid);
+    sqlite3_free(pConfig->zContentExprlist);
+    sqlite3_free(pConfig);
+  }
+}
+
+/*
+** Call sqlite3_declare_vtab() based on the contents of the configuration
+** object passed as the only argument. Return SQLITE_OK if successful, or
+** an SQLite error code if an error occurs.
+*/
+static int sqlite3Fts5ConfigDeclareVtab(Fts5Config *pConfig){
+  int i;
+  int rc = SQLITE_OK;
+  char *zSql;
+
+  zSql = sqlite3Fts5Mprintf(&rc, "CREATE TABLE x(");
+  for(i=0; zSql && i<pConfig->nCol; i++){
+    const char *zSep = (i==0?"":", ");
+    zSql = sqlite3Fts5Mprintf(&rc, "%z%s%Q", zSql, zSep, pConfig->azCol[i]);
+  }
+  zSql = sqlite3Fts5Mprintf(&rc, "%z, %Q HIDDEN, %s HIDDEN)",
+      zSql, pConfig->zName, FTS5_RANK_NAME
+  );
+
+  assert( zSql || rc==SQLITE_NOMEM );
+  if( zSql ){
+    rc = sqlite3_declare_vtab(pConfig->db, zSql);
+    sqlite3_free(zSql);
+  }
+
+  return rc;
+}
+
+/*
+** Tokenize the text passed via the second and third arguments.
+**
+** The callback is invoked once for each token in the input text. The
+** arguments passed to it are, in order:
+**
+**     void *pCtx          // Copy of 4th argument to sqlite3Fts5Tokenize()
+**     const char *pToken  // Pointer to buffer containing token
+**     int nToken          // Size of token in bytes
+**     int iStart          // Byte offset of start of token within input text
+**     int iEnd            // Byte offset of end of token within input text
+**     int iPos            // Position of token in input (first token is 0)
+**
+** If the callback returns a non-zero value the tokenization is abandoned
+** and no further callbacks are issued.
+**
+** This function returns SQLITE_OK if successful or an SQLite error code
+** if an error occurs. If the tokenization was abandoned early because
+** the callback returned SQLITE_DONE, this is not an error and this function
+** still returns SQLITE_OK. Or, if the tokenization was abandoned early
+** because the callback returned another non-zero value, it is assumed
+** to be an SQLite error code and returned to the caller.
+*/
+static int sqlite3Fts5Tokenize(
+  Fts5Config *pConfig,            /* FTS5 Configuration object */
+  int flags,                      /* FTS5_TOKENIZE_* flags */
+  const char *pText, int nText,   /* Text to tokenize */
+  void *pCtx,                     /* Context passed to xToken() */
+  int (*xToken)(void*, int, const char*, int, int, int)    /* Callback */
+){
+  int rc = SQLITE_OK;
+  if( pText ){
+    if( pConfig->t.pTok==0 ){
+      rc = sqlite3Fts5LoadTokenizer(pConfig);
+    }
+    if( rc==SQLITE_OK ){
+      if( pConfig->t.pApi1 ){
+        rc = pConfig->t.pApi1->xTokenize(
+            pConfig->t.pTok, pCtx, flags, pText, nText, xToken
+        );
+      }else{
+        rc = pConfig->t.pApi2->xTokenize(pConfig->t.pTok, pCtx, flags,
+            pText, nText, pConfig->t.pLocale, pConfig->t.nLocale, xToken
+        );
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Argument pIn points to the first character in what is expected to be
+** a comma-separated list of SQL literals followed by a ')' character.
+** If it actually is this, return a pointer to the ')'. Otherwise, return
+** NULL to indicate a parse error.
+*/
+static const char *fts5ConfigSkipArgs(const char *pIn){
+  const char *p = pIn;
+
+  while( 1 ){
+    p = fts5ConfigSkipWhitespace(p);
+    p = fts5ConfigSkipLiteral(p);
+    p = fts5ConfigSkipWhitespace(p);
+    if( p==0 || *p==')' ) break;
+    if( *p!=',' ){
+      p = 0;
+      break;
+    }
+    p++;
+  }
+
+  return p;
+}
+
+/*
+** Parameter zIn contains a rank() function specification. The format of
+** this is:
+**
+**   + Bareword (function name)
+**   + Open parenthesis - "("
+**   + Zero or more SQL literals in a comma separated list
+**   + Close parenthesis - ")"
+*/
+static int sqlite3Fts5ConfigParseRank(
+  const char *zIn,                /* Input string */
+  char **pzRank,                  /* OUT: Rank function name */
+  char **pzRankArgs               /* OUT: Rank function arguments */
+){
+  const char *p = zIn;
+  const char *pRank;
+  char *zRank = 0;
+  char *zRankArgs = 0;
+  int rc = SQLITE_OK;
+
+  *pzRank = 0;
+  *pzRankArgs = 0;
+
+  if( p==0 ){
+    rc = SQLITE_ERROR;
+  }else{
+    p = fts5ConfigSkipWhitespace(p);
+    pRank = p;
+    p = fts5ConfigSkipBareword(p);
+
+    if( p ){
+      zRank = sqlite3Fts5MallocZero(&rc, 1 + p - pRank);
+      if( zRank ) memcpy(zRank, pRank, p-pRank);
+    }else{
+      rc = SQLITE_ERROR;
+    }
+
+    if( rc==SQLITE_OK ){
+      p = fts5ConfigSkipWhitespace(p);
+      if( *p!='(' ) rc = SQLITE_ERROR;
+      p++;
+    }
+    if( rc==SQLITE_OK ){
+      const char *pArgs;
+      p = fts5ConfigSkipWhitespace(p);
+      pArgs = p;
+      if( *p!=')' ){
+        p = fts5ConfigSkipArgs(p);
+        if( p==0 ){
+          rc = SQLITE_ERROR;
+        }else{
+          zRankArgs = sqlite3Fts5MallocZero(&rc, 1 + p - pArgs);
+          if( zRankArgs ) memcpy(zRankArgs, pArgs, p-pArgs);
+        }
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(zRank);
+    assert( zRankArgs==0 );
+  }else{
+    *pzRank = zRank;
+    *pzRankArgs = zRankArgs;
+  }
+  return rc;
+}
+
+static int sqlite3Fts5ConfigSetValue(
+  Fts5Config *pConfig,
+  const char *zKey,
+  sqlite3_value *pVal,
+  int *pbBadkey
+){
+  int rc = SQLITE_OK;
+
+  if( 0==sqlite3_stricmp(zKey, "pgsz") ){
+    int pgsz = 0;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      pgsz = sqlite3_value_int(pVal);
+    }
+    if( pgsz<32 || pgsz>FTS5_MAX_PAGE_SIZE ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->pgsz = pgsz;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "hashsize") ){
+    int nHashSize = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nHashSize = sqlite3_value_int(pVal);
+    }
+    if( nHashSize<=0 ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->nHashSize = nHashSize;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "automerge") ){
+    int nAutomerge = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nAutomerge = sqlite3_value_int(pVal);
+    }
+    if( nAutomerge<0 || nAutomerge>64 ){
+      *pbBadkey = 1;
+    }else{
+      if( nAutomerge==1 ) nAutomerge = FTS5_DEFAULT_AUTOMERGE;
+      pConfig->nAutomerge = nAutomerge;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "usermerge") ){
+    int nUsermerge = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nUsermerge = sqlite3_value_int(pVal);
+    }
+    if( nUsermerge<2 || nUsermerge>16 ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->nUsermerge = nUsermerge;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "crisismerge") ){
+    int nCrisisMerge = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nCrisisMerge = sqlite3_value_int(pVal);
+    }
+    if( nCrisisMerge<0 ){
+      *pbBadkey = 1;
+    }else{
+      if( nCrisisMerge<=1 ) nCrisisMerge = FTS5_DEFAULT_CRISISMERGE;
+      if( nCrisisMerge>=FTS5_MAX_SEGMENT ) nCrisisMerge = FTS5_MAX_SEGMENT-1;
+      pConfig->nCrisisMerge = nCrisisMerge;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "deletemerge") ){
+    int nVal = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nVal = sqlite3_value_int(pVal);
+    }else{
+      *pbBadkey = 1;
+    }
+    if( nVal<0 ) nVal = FTS5_DEFAULT_DELETE_AUTOMERGE;
+    if( nVal>100 ) nVal = 0;
+    pConfig->nDeleteMerge = nVal;
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "rank") ){
+    const char *zIn = (const char*)sqlite3_value_text(pVal);
+    char *zRank;
+    char *zRankArgs;
+    rc = sqlite3Fts5ConfigParseRank(zIn, &zRank, &zRankArgs);
+    if( rc==SQLITE_OK ){
+      sqlite3_free(pConfig->zRank);
+      sqlite3_free(pConfig->zRankArgs);
+      pConfig->zRank = zRank;
+      pConfig->zRankArgs = zRankArgs;
+    }else if( rc==SQLITE_ERROR ){
+      rc = SQLITE_OK;
+      *pbBadkey = 1;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "secure-delete") ){
+    int bVal = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      bVal = sqlite3_value_int(pVal);
+    }
+    if( bVal<0 ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->bSecureDelete = (bVal ? 1 : 0);
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "insttoken") ){
+    int bVal = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      bVal = sqlite3_value_int(pVal);
+    }
+    if( bVal<0 ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->bPrefixInsttoken = (bVal ? 1 : 0);
+    }
+
+  }else{
+    *pbBadkey = 1;
+  }
+  return rc;
+}
+
+/*
+** Load the contents of the %_config table into memory.
+*/
+static int sqlite3Fts5ConfigLoad(Fts5Config *pConfig, int iCookie){
+  const char *zSelect = "SELECT k, v FROM %Q.'%q_config'";
+  char *zSql;
+  sqlite3_stmt *p = 0;
+  int rc = SQLITE_OK;
+  int iVersion = 0;
+
+  /* Set default values */
+  pConfig->pgsz = FTS5_DEFAULT_PAGE_SIZE;
+  pConfig->nAutomerge = FTS5_DEFAULT_AUTOMERGE;
+  pConfig->nUsermerge = FTS5_DEFAULT_USERMERGE;
+  pConfig->nCrisisMerge = FTS5_DEFAULT_CRISISMERGE;
+  pConfig->nHashSize = FTS5_DEFAULT_HASHSIZE;
+  pConfig->nDeleteMerge = FTS5_DEFAULT_DELETE_AUTOMERGE;
+
+  zSql = sqlite3Fts5Mprintf(&rc, zSelect, pConfig->zDb, pConfig->zName);
+  if( zSql ){
+    rc = sqlite3_prepare_v2(pConfig->db, zSql, -1, &p, 0);
+    sqlite3_free(zSql);
+  }
+
+  assert( rc==SQLITE_OK || p==0 );
+  if( rc==SQLITE_OK ){
+    while( SQLITE_ROW==sqlite3_step(p) ){
+      const char *zK = (const char*)sqlite3_column_text(p, 0);
+      sqlite3_value *pVal = sqlite3_column_value(p, 1);
+      if( 0==sqlite3_stricmp(zK, "version") ){
+        iVersion = sqlite3_value_int(pVal);
+      }else{
+        int bDummy = 0;
+        sqlite3Fts5ConfigSetValue(pConfig, zK, pVal, &bDummy);
+      }
+    }
+    rc = sqlite3_finalize(p);
+  }
+
+  if( rc==SQLITE_OK
+   && iVersion!=FTS5_CURRENT_VERSION
+   && iVersion!=FTS5_CURRENT_VERSION_SECUREDELETE
+  ){
+    rc = SQLITE_ERROR;
+    sqlite3Fts5ConfigErrmsg(pConfig, "invalid fts5 file format "
+        "(found %d, expected %d or %d) - run 'rebuild'",
+        iVersion, FTS5_CURRENT_VERSION, FTS5_CURRENT_VERSION_SECUREDELETE
+    );
+  }else{
+    pConfig->iVersion = iVersion;
+  }
+
+  if( rc==SQLITE_OK ){
+    pConfig->iCookie = iCookie;
+  }
+  return rc;
+}
+
+/*
+** Set (*pConfig->pzErrmsg) to point to an sqlite3_malloc()ed buffer
+** containing the error message created using printf() style formatting
+** string zFmt and its trailing arguments.
+*/
+static void sqlite3Fts5ConfigErrmsg(Fts5Config *pConfig, const char *zFmt, ...){
+  va_list ap;                     /* ... printf arguments */
+  char *zMsg = 0;
+
+  va_start(ap, zFmt);
+  zMsg = sqlite3_vmprintf(zFmt, ap);
+  if( pConfig->pzErrmsg ){
+    assert( *pConfig->pzErrmsg==0 );
+    *pConfig->pzErrmsg = zMsg;
+  }else{
+    sqlite3_free(zMsg);
+  }
+
+  va_end(ap);
+}
+
+
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+
+
+
+/* #include "fts5Int.h" */
+/* #include "fts5parse.h" */
+
+#ifndef SQLITE_FTS5_MAX_EXPR_DEPTH
+# define SQLITE_FTS5_MAX_EXPR_DEPTH 256
+#endif
+
+/*
+** All token types in the generated fts5parse.h file are greater than 0.
+*/
+#define FTS5_EOF 0
+
+#define FTS5_LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
+
+typedef struct Fts5ExprTerm Fts5ExprTerm;
+
+/*
+** Functions generated by lemon from fts5parse.y.
+*/
+static void *sqlite3Fts5ParserAlloc(void *(*mallocProc)(u64));
+static void sqlite3Fts5ParserFree(void*, void (*freeProc)(void*));
+static void sqlite3Fts5Parser(void*, int, Fts5Token, Fts5Parse*);
+#ifndef NDEBUG
+/* #include <stdio.h> */
+static void sqlite3Fts5ParserTrace(FILE*, char*);
+#endif
+static int sqlite3Fts5ParserFallback(int);
+
+
+struct Fts5Expr {
+  Fts5Index *pIndex;
+  Fts5Config *pConfig;
+  Fts5ExprNode *pRoot;
+  int bDesc;                      /* Iterate in descending rowid order */
+  int nPhrase;                    /* Number of phrases in expression */
+  Fts5ExprPhrase **apExprPhrase;  /* Pointers to phrase objects */
+};
+
+/*
+** eType:
+**   Expression node type. Usually one of:
+**
+**       FTS5_AND                 (nChild, apChild valid)
+**       FTS5_OR                  (nChild, apChild valid)
+**       FTS5_NOT                 (nChild, apChild valid)
+**       FTS5_STRING              (pNear valid)
+**       FTS5_TERM                (pNear valid)
+**
+**   An expression node with eType==0 may also exist. It always matches zero
+**   rows. This is created when a phrase containing no tokens is parsed.
+**   e.g. "".
+**
+** iHeight:
+**   Distance from this node to furthest leaf. This is always 0 for nodes
+**   of type FTS5_STRING and FTS5_TERM. For all other nodes it is one
+**   greater than the largest child value.
+*/
+struct Fts5ExprNode {
+  int eType;                      /* Node type */
+  int bEof;                       /* True at EOF */
+  int bNomatch;                   /* True if entry is not a match */
+  int iHeight;                    /* Distance to tree leaf nodes */
+
+  /* Next method for this node. */
+  int (*xNext)(Fts5Expr*, Fts5ExprNode*, int, i64);
+
+  i64 iRowid;                     /* Current rowid */
+  Fts5ExprNearset *pNear;         /* For FTS5_STRING - cluster of phrases */
+
+  /* Child nodes. For a NOT node, this array always contains 2 entries. For
+  ** AND or OR nodes, it contains 2 or more entries.  */
+  int nChild;                     /* Number of child nodes */
+  Fts5ExprNode *apChild[1];       /* Array of child nodes */
+};
+
+#define Fts5NodeIsString(p) ((p)->eType==FTS5_TERM || (p)->eType==FTS5_STRING)
+
+/*
+** Invoke the xNext method of an Fts5ExprNode object. This macro should be
+** used as if it has the same signature as the xNext() methods themselves.
+*/
+#define fts5ExprNodeNext(a,b,c,d) (b)->xNext((a), (b), (c), (d))
+
+/*
+** An instance of the following structure represents a single search term
+** or term prefix.
+*/
+struct Fts5ExprTerm {
+  u8 bPrefix;                     /* True for a prefix term */
+  u8 bFirst;                      /* True if token must be first in column */
+  char *pTerm;                    /* Term data */
+  int nQueryTerm;                 /* Effective size of term in bytes */
+  int nFullTerm;                  /* Size of term in bytes incl. tokendata */
+  Fts5IndexIter *pIter;           /* Iterator for this term */
+  Fts5ExprTerm *pSynonym;         /* Pointer to first in list of synonyms */
+};
+
+/*
+** A phrase. One or more terms that must appear in a contiguous sequence
+** within a document for it to match.
+*/
+struct Fts5ExprPhrase {
+  Fts5ExprNode *pNode;            /* FTS5_STRING node this phrase is part of */
+  Fts5Buffer poslist;             /* Current position list */
+  int nTerm;                      /* Number of entries in aTerm[] */
+  Fts5ExprTerm aTerm[1];          /* Terms that make up this phrase */
+};
+
+/*
+** One or more phrases that must appear within a certain token distance of
+** each other within each matching document.
+*/
+struct Fts5ExprNearset {
+  int nNear;                      /* NEAR parameter */
+  Fts5Colset *pColset;            /* Columns to search (NULL -> all columns) */
+  int nPhrase;                    /* Number of entries in aPhrase[] array */
+  Fts5ExprPhrase *apPhrase[1];    /* Array of phrase pointers */
+};
+
+
+/*
+** Parse context.
+*/
+struct Fts5Parse {
+  Fts5Config *pConfig;
+  char *zErr;
+  int rc;
+  int nPhrase;                    /* Size of apPhrase array */
+  Fts5ExprPhrase **apPhrase;      /* Array of all phrases */
+  Fts5ExprNode *pExpr;            /* Result of a successful parse */
+  int bPhraseToAnd;               /* Convert "a+b" to "a AND b" */
+};
+
+/*
+** Check that the Fts5ExprNode.iHeight variables are set correctly in
+** the expression tree passed as the only argument.
+*/
+#ifndef NDEBUG
+static void assert_expr_depth_ok(int rc, Fts5ExprNode *p){
+  if( rc==SQLITE_OK ){
+    if( p->eType==FTS5_TERM || p->eType==FTS5_STRING || p->eType==0 ){
+      assert( p->iHeight==0 );
+    }else{
+      int ii;
+      int iMaxChild = 0;
+      for(ii=0; ii<p->nChild; ii++){
+        Fts5ExprNode *pChild = p->apChild[ii];
+        iMaxChild = MAX(iMaxChild, pChild->iHeight);
+        assert_expr_depth_ok(SQLITE_OK, pChild);
+      }
+      assert( p->iHeight==iMaxChild+1 );
+    }
+  }
+}
+#else
+# define assert_expr_depth_ok(rc, p)
+#endif
+
+static void sqlite3Fts5ParseError(Fts5Parse *pParse, const char *zFmt, ...){
+  va_list ap;
+  va_start(ap, zFmt);
+  if( pParse->rc==SQLITE_OK ){
+    assert( pParse->zErr==0 );
+    pParse->zErr = sqlite3_vmprintf(zFmt, ap);
+    pParse->rc = SQLITE_ERROR;
+  }
+  va_end(ap);
+}
+
+static int fts5ExprIsspace(char t){
+  return t==' ' || t=='\t' || t=='\n' || t=='\r';
+}
+
+/*
+** Read the first token from the nul-terminated string at *pz.
+*/
+static int fts5ExprGetToken(
+  Fts5Parse *pParse,
+  const char **pz,                /* IN/OUT: Pointer into buffer */
+  Fts5Token *pToken
+){
+  const char *z = *pz;
+  int tok;
+
+  /* Skip past any whitespace */
+  while( fts5ExprIsspace(*z) ) z++;
+
+  pToken->p = z;
+  pToken->n = 1;
+  switch( *z ){
+    case '(':  tok = FTS5_LP;    break;
+    case ')':  tok = FTS5_RP;    break;
+    case '{':  tok = FTS5_LCP;   break;
+    case '}':  tok = FTS5_RCP;   break;
+    case ':':  tok = FTS5_COLON; break;
+    case ',':  tok = FTS5_COMMA; break;
+    case '+':  tok = FTS5_PLUS;  break;
+    case '*':  tok = FTS5_STAR;  break;
+    case '-':  tok = FTS5_MINUS; break;
+    case '^':  tok = FTS5_CARET; break;
+    case '\0': tok = FTS5_EOF;   break;
+
+    case '"': {
+      const char *z2;
+      tok = FTS5_STRING;
+
+      for(z2=&z[1]; 1; z2++){
+        if( z2[0]=='"' ){
+          z2++;
+          if( z2[0]!='"' ) break;
+        }
+        if( z2[0]=='\0' ){
+          sqlite3Fts5ParseError(pParse, "unterminated string");
+          return FTS5_EOF;
+        }
+      }
+      pToken->n = (z2 - z);
+      break;
+    }
+
+    default: {
+      const char *z2;
+      if( sqlite3Fts5IsBareword(z[0])==0 ){
+        sqlite3Fts5ParseError(pParse, "fts5: syntax error near \"%.1s\"", z);
+        return FTS5_EOF;
+      }
+      tok = FTS5_STRING;
+      for(z2=&z[1]; sqlite3Fts5IsBareword(*z2); z2++);
+      pToken->n = (z2 - z);
+      if( pToken->n==2 && memcmp(pToken->p, "OR", 2)==0 )  tok = FTS5_OR;
+      if( pToken->n==3 && memcmp(pToken->p, "NOT", 3)==0 ) tok = FTS5_NOT;
+      if( pToken->n==3 && memcmp(pToken->p, "AND", 3)==0 ) tok = FTS5_AND;
+      break;
+    }
+  }
+
+  *pz = &pToken->p[pToken->n];
+  return tok;
+}
+
+static void *fts5ParseAlloc(u64 t){ return sqlite3_malloc64((sqlite3_int64)t);}
+static void fts5ParseFree(void *p){ sqlite3_free(p); }
+
+static int sqlite3Fts5ExprNew(
+  Fts5Config *pConfig,            /* FTS5 Configuration */
+  int bPhraseToAnd,
+  int iCol,
+  const char *zExpr,              /* Expression text */
+  Fts5Expr **ppNew,
+  char **pzErr
+){
+  Fts5Parse sParse;
+  Fts5Token token;
+  const char *z = zExpr;
+  int t;                          /* Next token type */
+  void *pEngine;
+  Fts5Expr *pNew;
+
+  *ppNew = 0;
+  *pzErr = 0;
+  memset(&sParse, 0, sizeof(sParse));
+  sParse.bPhraseToAnd = bPhraseToAnd;
+  pEngine = sqlite3Fts5ParserAlloc(fts5ParseAlloc);
+  if( pEngine==0 ){ return SQLITE_NOMEM; }
+  sParse.pConfig = pConfig;
+
+  do {
+    t = fts5ExprGetToken(&sParse, &z, &token);
+    sqlite3Fts5Parser(pEngine, t, token, &sParse);
+  }while( sParse.rc==SQLITE_OK && t!=FTS5_EOF );
+  sqlite3Fts5ParserFree(pEngine, fts5ParseFree);
+
+  assert( sParse.pExpr || sParse.rc!=SQLITE_OK );
+  assert_expr_depth_ok(sParse.rc, sParse.pExpr);
+
+  /* If the LHS of the MATCH expression was a user column, apply the
+  ** implicit column-filter.  */
+  if( sParse.rc==SQLITE_OK && iCol<pConfig->nCol ){
+    int n = sizeof(Fts5Colset);
+    Fts5Colset *pColset = (Fts5Colset*)sqlite3Fts5MallocZero(&sParse.rc, n);
+    if( pColset ){
+      pColset->nCol = 1;
+      pColset->aiCol[0] = iCol;
+      sqlite3Fts5ParseSetColset(&sParse, sParse.pExpr, pColset);
+    }
+  }
+
+  assert( sParse.rc!=SQLITE_OK || sParse.zErr==0 );
+  if( sParse.rc==SQLITE_OK ){
+    *ppNew = pNew = sqlite3_malloc(sizeof(Fts5Expr));
+    if( pNew==0 ){
+      sParse.rc = SQLITE_NOMEM;
+      sqlite3Fts5ParseNodeFree(sParse.pExpr);
+    }else{
+      pNew->pRoot = sParse.pExpr;
+      pNew->pIndex = 0;
+      pNew->pConfig = pConfig;
+      pNew->apExprPhrase = sParse.apPhrase;
+      pNew->nPhrase = sParse.nPhrase;
+      pNew->bDesc = 0;
+      sParse.apPhrase = 0;
+    }
+  }else{
+    sqlite3Fts5ParseNodeFree(sParse.pExpr);
+  }
+
+  sqlite3_free(sParse.apPhrase);
+  if( 0==*pzErr ){
+    *pzErr = sParse.zErr;
+  }else{
+    sqlite3_free(sParse.zErr);
+  }
+  return sParse.rc;
+}
+
+/*
+** Assuming that buffer z is at least nByte bytes in size and contains a
+** valid utf-8 string, return the number of characters in the string.
+*/
+static int fts5ExprCountChar(const char *z, int nByte){
+  int nRet = 0;
+  int ii;
+  for(ii=0; ii<nByte; ii++){
+    if( (z[ii] & 0xC0)!=0x80 ) nRet++;
+  }
+  return nRet;
+}
+
+/*
+** This function is only called when using the special 'trigram' tokenizer.
+** Argument zText contains the text of a LIKE or GLOB pattern matched
+** against column iCol. This function creates and compiles an FTS5 MATCH
+** expression that will match a superset of the rows matched by the LIKE or
+** GLOB. If successful, SQLITE_OK is returned. Otherwise, an SQLite error
+** code.
+*/
+static int sqlite3Fts5ExprPattern(
+  Fts5Config *pConfig, int bGlob, int iCol, const char *zText, Fts5Expr **pp
+){
+  i64 nText = strlen(zText);
+  char *zExpr = (char*)sqlite3_malloc64(nText*4 + 1);
+  int rc = SQLITE_OK;
+
+  if( zExpr==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    char aSpec[3];
+    int iOut = 0;
+    int i = 0;
+    int iFirst = 0;
+
+    if( bGlob==0 ){
+      aSpec[0] = '_';
+      aSpec[1] = '%';
+      aSpec[2] = 0;
+    }else{
+      aSpec[0] = '*';
+      aSpec[1] = '?';
+      aSpec[2] = '[';
+    }
+
+    while( i<=nText ){
+      if( i==nText
+       || zText[i]==aSpec[0] || zText[i]==aSpec[1] || zText[i]==aSpec[2]
+      ){
+
+        if( fts5ExprCountChar(&zText[iFirst], i-iFirst)>=3 ){
+          int jj;
+          zExpr[iOut++] = '"';
+          for(jj=iFirst; jj<i; jj++){
+            zExpr[iOut++] = zText[jj];
+            if( zText[jj]=='"' ) zExpr[iOut++] = '"';
+          }
+          zExpr[iOut++] = '"';
+          zExpr[iOut++] = ' ';
+        }
+        if( zText[i]==aSpec[2] ){
+          i += 2;
+          if( zText[i-1]=='^' ) i++;
+          while( i<nText && zText[i]!=']' ) i++;
+        }
+        iFirst = i+1;
+      }
+      i++;
+    }
+    if( iOut>0 ){
+      int bAnd = 0;
+      if( pConfig->eDetail!=FTS5_DETAIL_FULL ){
+        bAnd = 1;
+        if( pConfig->eDetail==FTS5_DETAIL_NONE ){
+          iCol = pConfig->nCol;
+        }
+      }
+      zExpr[iOut] = '\0';
+      rc = sqlite3Fts5ExprNew(pConfig, bAnd, iCol, zExpr, pp,pConfig->pzErrmsg);
+    }else{
+      *pp = 0;
+    }
+    sqlite3_free(zExpr);
+  }
+
+  return rc;
+}
+
+/*
+** Free the expression node object passed as the only argument.
+*/
+static void sqlite3Fts5ParseNodeFree(Fts5ExprNode *p){
+  if( p ){
+    int i;
+    for(i=0; i<p->nChild; i++){
+      sqlite3Fts5ParseNodeFree(p->apChild[i]);
+    }
+    sqlite3Fts5ParseNearsetFree(p->pNear);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Free the expression object passed as the only argument.
+*/
+static void sqlite3Fts5ExprFree(Fts5Expr *p){
+  if( p ){
+    sqlite3Fts5ParseNodeFree(p->pRoot);
+    sqlite3_free(p->apExprPhrase);
+    sqlite3_free(p);
+  }
+}
+
+static int sqlite3Fts5ExprAnd(Fts5Expr **pp1, Fts5Expr *p2){
+  Fts5Parse sParse;
+  memset(&sParse, 0, sizeof(sParse));
+
+  if( *pp1 && p2 ){
+    Fts5Expr *p1 = *pp1;
+    int nPhrase = p1->nPhrase + p2->nPhrase;
+
+    p1->pRoot = sqlite3Fts5ParseNode(&sParse, FTS5_AND, p1->pRoot, p2->pRoot,0);
+    p2->pRoot = 0;
+
+    if( sParse.rc==SQLITE_OK ){
+      Fts5ExprPhrase **ap = (Fts5ExprPhrase**)sqlite3_realloc(
+          p1->apExprPhrase, nPhrase * sizeof(Fts5ExprPhrase*)
+      );
+      if( ap==0 ){
+        sParse.rc = SQLITE_NOMEM;
+      }else{
+        int i;
+        memmove(&ap[p2->nPhrase], ap, p1->nPhrase*sizeof(Fts5ExprPhrase*));
+        for(i=0; i<p2->nPhrase; i++){
+          ap[i] = p2->apExprPhrase[i];
+        }
+        p1->nPhrase = nPhrase;
+        p1->apExprPhrase = ap;
+      }
+    }
+    sqlite3_free(p2->apExprPhrase);
+    sqlite3_free(p2);
+  }else if( p2 ){
+    *pp1 = p2;
+  }
+
+  return sParse.rc;
+}
+
+/*
+** Argument pTerm must be a synonym iterator. Return the current rowid
+** that it points to.
+*/
+static i64 fts5ExprSynonymRowid(Fts5ExprTerm *pTerm, int bDesc, int *pbEof){
+  i64 iRet = 0;
+  int bRetValid = 0;
+  Fts5ExprTerm *p;
+
+  assert( pTerm );
+  assert( pTerm->pSynonym );
+  assert( bDesc==0 || bDesc==1 );
+  for(p=pTerm; p; p=p->pSynonym){
+    if( 0==sqlite3Fts5IterEof(p->pIter) ){
+      i64 iRowid = p->pIter->iRowid;
+      if( bRetValid==0 || (bDesc!=(iRowid<iRet)) ){
+        iRet = iRowid;
+        bRetValid = 1;
+      }
+    }
+  }
+
+  if( pbEof && bRetValid==0 ) *pbEof = 1;
+  return iRet;
+}
+
+/*
+** Argument pTerm must be a synonym iterator.
+*/
+static int fts5ExprSynonymList(
+  Fts5ExprTerm *pTerm,
+  i64 iRowid,
+  Fts5Buffer *pBuf,               /* Use this buffer for space if required */
+  u8 **pa, int *pn
+){
+  Fts5PoslistReader aStatic[4];
+  Fts5PoslistReader *aIter = aStatic;
+  int nIter = 0;
+  int nAlloc = 4;
+  int rc = SQLITE_OK;
+  Fts5ExprTerm *p;
+
+  assert( pTerm->pSynonym );
+  for(p=pTerm; p; p=p->pSynonym){
+    Fts5IndexIter *pIter = p->pIter;
+    if( sqlite3Fts5IterEof(pIter)==0 && pIter->iRowid==iRowid ){
+      if( pIter->nData==0 ) continue;
+      if( nIter==nAlloc ){
+        sqlite3_int64 nByte = sizeof(Fts5PoslistReader) * nAlloc * 2;
+        Fts5PoslistReader *aNew = (Fts5PoslistReader*)sqlite3_malloc64(nByte);
+        if( aNew==0 ){
+          rc = SQLITE_NOMEM;
+          goto synonym_poslist_out;
+        }
+        memcpy(aNew, aIter, sizeof(Fts5PoslistReader) * nIter);
+        nAlloc = nAlloc*2;
+        if( aIter!=aStatic ) sqlite3_free(aIter);
+        aIter = aNew;
+      }
+      sqlite3Fts5PoslistReaderInit(pIter->pData, pIter->nData, &aIter[nIter]);
+      assert( aIter[nIter].bEof==0 );
+      nIter++;
+    }
+  }
+
+  if( nIter==1 ){
+    *pa = (u8*)aIter[0].a;
+    *pn = aIter[0].n;
+  }else{
+    Fts5PoslistWriter writer = {0};
+    i64 iPrev = -1;
+    fts5BufferZero(pBuf);
+    while( 1 ){
+      int i;
+      i64 iMin = FTS5_LARGEST_INT64;
+      for(i=0; i<nIter; i++){
+        if( aIter[i].bEof==0 ){
+          if( aIter[i].iPos==iPrev ){
+            if( sqlite3Fts5PoslistReaderNext(&aIter[i]) ) continue;
+          }
+          if( aIter[i].iPos<iMin ){
+            iMin = aIter[i].iPos;
+          }
+        }
+      }
+      if( iMin==FTS5_LARGEST_INT64 || rc!=SQLITE_OK ) break;
+      rc = sqlite3Fts5PoslistWriterAppend(pBuf, &writer, iMin);
+      iPrev = iMin;
+    }
+    if( rc==SQLITE_OK ){
+      *pa = pBuf->p;
+      *pn = pBuf->n;
+    }
+  }
+
+ synonym_poslist_out:
+  if( aIter!=aStatic ) sqlite3_free(aIter);
+  return rc;
+}
+
+
+/*
+** All individual term iterators in pPhrase are guaranteed to be valid and
+** pointing to the same rowid when this function is called. This function
+** checks if the current rowid really is a match, and if so populates
+** the pPhrase->poslist buffer accordingly. Output parameter *pbMatch
+** is set to true if this is really a match, or false otherwise.
+**
+** SQLITE_OK is returned if an error occurs, or an SQLite error code
+** otherwise. It is not considered an error code if the current rowid is
+** not a match.
+*/
+static int fts5ExprPhraseIsMatch(
+  Fts5ExprNode *pNode,            /* Node pPhrase belongs to */
+  Fts5ExprPhrase *pPhrase,        /* Phrase object to initialize */
+  int *pbMatch                    /* OUT: Set to true if really a match */
+){
+  Fts5PoslistWriter writer = {0};
+  Fts5PoslistReader aStatic[4];
+  Fts5PoslistReader *aIter = aStatic;
+  int i;
+  int rc = SQLITE_OK;
+  int bFirst = pPhrase->aTerm[0].bFirst;
+
+  fts5BufferZero(&pPhrase->poslist);
+
+  /* If the aStatic[] array is not large enough, allocate a large array
+  ** using sqlite3_malloc(). This approach could be improved upon. */
+  if( pPhrase->nTerm>ArraySize(aStatic) ){
+    sqlite3_int64 nByte = sizeof(Fts5PoslistReader) * pPhrase->nTerm;
+    aIter = (Fts5PoslistReader*)sqlite3_malloc64(nByte);
+    if( !aIter ) return SQLITE_NOMEM;
+  }
+  memset(aIter, 0, sizeof(Fts5PoslistReader) * pPhrase->nTerm);
+
+  /* Initialize a term iterator for each term in the phrase */
+  for(i=0; i<pPhrase->nTerm; i++){
+    Fts5ExprTerm *pTerm = &pPhrase->aTerm[i];
+    int n = 0;
+    int bFlag = 0;
+    u8 *a = 0;
+    if( pTerm->pSynonym ){
+      Fts5Buffer buf = {0, 0, 0};
+      rc = fts5ExprSynonymList(pTerm, pNode->iRowid, &buf, &a, &n);
+      if( rc ){
+        sqlite3_free(a);
+        goto ismatch_out;
+      }
+      if( a==buf.p ) bFlag = 1;
+    }else{
+      a = (u8*)pTerm->pIter->pData;
+      n = pTerm->pIter->nData;
+    }
+    sqlite3Fts5PoslistReaderInit(a, n, &aIter[i]);
+    aIter[i].bFlag = (u8)bFlag;
+    if( aIter[i].bEof ) goto ismatch_out;
+  }
+
+  while( 1 ){
+    int bMatch;
+    i64 iPos = aIter[0].iPos;
+    do {
+      bMatch = 1;
+      for(i=0; i<pPhrase->nTerm; i++){
+        Fts5PoslistReader *pPos = &aIter[i];
+        i64 iAdj = iPos + i;
+        if( pPos->iPos!=iAdj ){
+          bMatch = 0;
+          while( pPos->iPos<iAdj ){
+            if( sqlite3Fts5PoslistReaderNext(pPos) ) goto ismatch_out;
+          }
+          if( pPos->iPos>iAdj ) iPos = pPos->iPos-i;
+        }
+      }
+    }while( bMatch==0 );
+
+    /* Append position iPos to the output */
+    if( bFirst==0 || FTS5_POS2OFFSET(iPos)==0 ){
+      rc = sqlite3Fts5PoslistWriterAppend(&pPhrase->poslist, &writer, iPos);
+      if( rc!=SQLITE_OK ) goto ismatch_out;
+    }
+
+    for(i=0; i<pPhrase->nTerm; i++){
+      if( sqlite3Fts5PoslistReaderNext(&aIter[i]) ) goto ismatch_out;
+    }
+  }
+
+ ismatch_out:
+  *pbMatch = (pPhrase->poslist.n>0);
+  for(i=0; i<pPhrase->nTerm; i++){
+    if( aIter[i].bFlag ) sqlite3_free((u8*)aIter[i].a);
+  }
+  if( aIter!=aStatic ) sqlite3_free(aIter);
+  return rc;
+}
+
+typedef struct Fts5LookaheadReader Fts5LookaheadReader;
+struct Fts5LookaheadReader {
+  const u8 *a;                    /* Buffer containing position list */
+  int n;                          /* Size of buffer a[] in bytes */
+  int i;                          /* Current offset in position list */
+  i64 iPos;                       /* Current position */
+  i64 iLookahead;                 /* Next position */
+};
+
+#define FTS5_LOOKAHEAD_EOF (((i64)1) << 62)
+
+static int fts5LookaheadReaderNext(Fts5LookaheadReader *p){
+  p->iPos = p->iLookahead;
+  if( sqlite3Fts5PoslistNext64(p->a, p->n, &p->i, &p->iLookahead) ){
+    p->iLookahead = FTS5_LOOKAHEAD_EOF;
+  }
+  return (p->iPos==FTS5_LOOKAHEAD_EOF);
+}
+
+static int fts5LookaheadReaderInit(
+  const u8 *a, int n,             /* Buffer to read position list from */
+  Fts5LookaheadReader *p          /* Iterator object to initialize */
+){
+  memset(p, 0, sizeof(Fts5LookaheadReader));
+  p->a = a;
+  p->n = n;
+  fts5LookaheadReaderNext(p);
+  return fts5LookaheadReaderNext(p);
+}
+
+typedef struct Fts5NearTrimmer Fts5NearTrimmer;
+struct Fts5NearTrimmer {
+  Fts5LookaheadReader reader;     /* Input iterator */
+  Fts5PoslistWriter writer;       /* Writer context */
+  Fts5Buffer *pOut;               /* Output poslist */
+};
+
+/*
+** The near-set object passed as the first argument contains more than
+** one phrase. All phrases currently point to the same row. The
+** Fts5ExprPhrase.poslist buffers are populated accordingly. This function
+** tests if the current row contains instances of each phrase sufficiently
+** close together to meet the NEAR constraint. Non-zero is returned if it
+** does, or zero otherwise.
+**
+** If in/out parameter (*pRc) is set to other than SQLITE_OK when this
+** function is called, it is a no-op. Or, if an error (e.g. SQLITE_NOMEM)
+** occurs within this function (*pRc) is set accordingly before returning.
+** The return value is undefined in both these cases.
+**
+** If no error occurs and non-zero (a match) is returned, the position-list
+** of each phrase object is edited to contain only those entries that
+** meet the constraint before returning.
+*/
+static int fts5ExprNearIsMatch(int *pRc, Fts5ExprNearset *pNear){
+  Fts5NearTrimmer aStatic[4];
+  Fts5NearTrimmer *a = aStatic;
+  Fts5ExprPhrase **apPhrase = pNear->apPhrase;
+
+  int i;
+  int rc = *pRc;
+  int bMatch;
+
+  assert( pNear->nPhrase>1 );
+
+  /* If the aStatic[] array is not large enough, allocate a large array
+  ** using sqlite3_malloc(). This approach could be improved upon. */
+  if( pNear->nPhrase>ArraySize(aStatic) ){
+    sqlite3_int64 nByte = sizeof(Fts5NearTrimmer) * pNear->nPhrase;
+    a = (Fts5NearTrimmer*)sqlite3Fts5MallocZero(&rc, nByte);
+  }else{
+    memset(aStatic, 0, sizeof(aStatic));
+  }
+  if( rc!=SQLITE_OK ){
+    *pRc = rc;
+    return 0;
+  }
+
+  /* Initialize a lookahead iterator for each phrase. After passing the
+  ** buffer and buffer size to the lookaside-reader init function, zero
+  ** the phrase poslist buffer. The new poslist for the phrase (containing
+  ** the same entries as the original with some entries removed on account
+  ** of the NEAR constraint) is written over the original even as it is
+  ** being read. This is safe as the entries for the new poslist are a
+  ** subset of the old, so it is not possible for data yet to be read to
+  ** be overwritten.  */
+  for(i=0; i<pNear->nPhrase; i++){
+    Fts5Buffer *pPoslist = &apPhrase[i]->poslist;
+    fts5LookaheadReaderInit(pPoslist->p, pPoslist->n, &a[i].reader);
+    pPoslist->n = 0;
+    a[i].pOut = pPoslist;
+  }
+
+  while( 1 ){
+    int iAdv;
+    i64 iMin;
+    i64 iMax;
+
+    /* This block advances the phrase iterators until they point to a set of
+    ** entries that together comprise a match.  */
+    iMax = a[0].reader.iPos;
+    do {
+      bMatch = 1;
+      for(i=0; i<pNear->nPhrase; i++){
+        Fts5LookaheadReader *pPos = &a[i].reader;
+        iMin = iMax - pNear->apPhrase[i]->nTerm - pNear->nNear;
+        if( pPos->iPos<iMin || pPos->iPos>iMax ){
+          bMatch = 0;
+          while( pPos->iPos<iMin ){
+            if( fts5LookaheadReaderNext(pPos) ) goto ismatch_out;
+          }
+          if( pPos->iPos>iMax ) iMax = pPos->iPos;
+        }
+      }
+    }while( bMatch==0 );
+
+    /* Add an entry to each output position list */
+    for(i=0; i<pNear->nPhrase; i++){
+      i64 iPos = a[i].reader.iPos;
+      Fts5PoslistWriter *pWriter = &a[i].writer;
+      if( a[i].pOut->n==0 || iPos!=pWriter->iPrev ){
+        sqlite3Fts5PoslistWriterAppend(a[i].pOut, pWriter, iPos);
+      }
+    }
+
+    iAdv = 0;
+    iMin = a[0].reader.iLookahead;
+    for(i=0; i<pNear->nPhrase; i++){
+      if( a[i].reader.iLookahead < iMin ){
+        iMin = a[i].reader.iLookahead;
+        iAdv = i;
+      }
+    }
+    if( fts5LookaheadReaderNext(&a[iAdv].reader) ) goto ismatch_out;
+  }
+
+  ismatch_out: {
+    int bRet = a[0].pOut->n>0;
+    *pRc = rc;
+    if( a!=aStatic ) sqlite3_free(a);
+    return bRet;
+  }
+}
+
+/*
+** Advance iterator pIter until it points to a value equal to or laster
+** than the initial value of *piLast. If this means the iterator points
+** to a value laster than *piLast, update *piLast to the new lastest value.
+**
+** If the iterator reaches EOF, set *pbEof to true before returning. If
+** an error occurs, set *pRc to an error code. If either *pbEof or *pRc
+** are set, return a non-zero value. Otherwise, return zero.
+*/
+static int fts5ExprAdvanceto(
+  Fts5IndexIter *pIter,           /* Iterator to advance */
+  int bDesc,                      /* True if iterator is "rowid DESC" */
+  i64 *piLast,                    /* IN/OUT: Lastest rowid seen so far */
+  int *pRc,                       /* OUT: Error code */
+  int *pbEof                      /* OUT: Set to true if EOF */
+){
+  i64 iLast = *piLast;
+  i64 iRowid;
+
+  iRowid = pIter->iRowid;
+  if( (bDesc==0 && iLast>iRowid) || (bDesc && iLast<iRowid) ){
+    int rc = sqlite3Fts5IterNextFrom(pIter, iLast);
+    if( rc || sqlite3Fts5IterEof(pIter) ){
+      *pRc = rc;
+      *pbEof = 1;
+      return 1;
+    }
+    iRowid = pIter->iRowid;
+    assert( (bDesc==0 && iRowid>=iLast) || (bDesc==1 && iRowid<=iLast) );
+  }
+  *piLast = iRowid;
+
+  return 0;
+}
+
+static int fts5ExprSynonymAdvanceto(
+  Fts5ExprTerm *pTerm,            /* Term iterator to advance */
+  int bDesc,                      /* True if iterator is "rowid DESC" */
+  i64 *piLast,                    /* IN/OUT: Lastest rowid seen so far */
+  int *pRc                        /* OUT: Error code */
+){
+  int rc = SQLITE_OK;
+  i64 iLast = *piLast;
+  Fts5ExprTerm *p;
+  int bEof = 0;
+
+  for(p=pTerm; rc==SQLITE_OK && p; p=p->pSynonym){
+    if( sqlite3Fts5IterEof(p->pIter)==0 ){
+      i64 iRowid = p->pIter->iRowid;
+      if( (bDesc==0 && iLast>iRowid) || (bDesc && iLast<iRowid) ){
+        rc = sqlite3Fts5IterNextFrom(p->pIter, iLast);
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    *pRc = rc;
+    bEof = 1;
+  }else{
+    *piLast = fts5ExprSynonymRowid(pTerm, bDesc, &bEof);
+  }
+  return bEof;
+}
+
+
+static int fts5ExprNearTest(
+  int *pRc,
+  Fts5Expr *pExpr,                /* Expression that pNear is a part of */
+  Fts5ExprNode *pNode             /* The "NEAR" node (FTS5_STRING) */
+){
+  Fts5ExprNearset *pNear = pNode->pNear;
+  int rc = *pRc;
+
+  if( pExpr->pConfig->eDetail!=FTS5_DETAIL_FULL ){
+    Fts5ExprTerm *pTerm;
+    Fts5ExprPhrase *pPhrase = pNear->apPhrase[0];
+    pPhrase->poslist.n = 0;
+    for(pTerm=&pPhrase->aTerm[0]; pTerm; pTerm=pTerm->pSynonym){
+      Fts5IndexIter *pIter = pTerm->pIter;
+      if( sqlite3Fts5IterEof(pIter)==0 ){
+        if( pIter->iRowid==pNode->iRowid && pIter->nData>0 ){
+          pPhrase->poslist.n = 1;
+        }
+      }
+    }
+    return pPhrase->poslist.n;
+  }else{
+    int i;
+
+    /* Check that each phrase in the nearset matches the current row.
+    ** Populate the pPhrase->poslist buffers at the same time. If any
+    ** phrase is not a match, break out of the loop early.  */
+    for(i=0; rc==SQLITE_OK && i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      if( pPhrase->nTerm>1 || pPhrase->aTerm[0].pSynonym
+       || pNear->pColset || pPhrase->aTerm[0].bFirst
+      ){
+        int bMatch = 0;
+        rc = fts5ExprPhraseIsMatch(pNode, pPhrase, &bMatch);
+        if( bMatch==0 ) break;
+      }else{
+        Fts5IndexIter *pIter = pPhrase->aTerm[0].pIter;
+        fts5BufferSet(&rc, &pPhrase->poslist, pIter->nData, pIter->pData);
+      }
+    }
+
+    *pRc = rc;
+    if( i==pNear->nPhrase && (i==1 || fts5ExprNearIsMatch(pRc, pNear)) ){
+      return 1;
+    }
+    return 0;
+  }
+}
+
+
+/*
+** Initialize all term iterators in the pNear object. If any term is found
+** to match no documents at all, return immediately without initializing any
+** further iterators.
+**
+** If an error occurs, return an SQLite error code. Otherwise, return
+** SQLITE_OK. It is not considered an error if some term matches zero
+** documents.
+*/
+static int fts5ExprNearInitAll(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode
+){
+  Fts5ExprNearset *pNear = pNode->pNear;
+  int i;
+
+  assert( pNode->bNomatch==0 );
+  for(i=0; i<pNear->nPhrase; i++){
+    Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+    if( pPhrase->nTerm==0 ){
+      pNode->bEof = 1;
+      return SQLITE_OK;
+    }else{
+      int j;
+      for(j=0; j<pPhrase->nTerm; j++){
+        Fts5ExprTerm *pTerm = &pPhrase->aTerm[j];
+        Fts5ExprTerm *p;
+        int bHit = 0;
+
+        for(p=pTerm; p; p=p->pSynonym){
+          int rc;
+          if( p->pIter ){
+            sqlite3Fts5IterClose(p->pIter);
+            p->pIter = 0;
+          }
+          rc = sqlite3Fts5IndexQuery(
+              pExpr->pIndex, p->pTerm, p->nQueryTerm,
+              (pTerm->bPrefix ? FTS5INDEX_QUERY_PREFIX : 0) |
+              (pExpr->bDesc ? FTS5INDEX_QUERY_DESC : 0),
+              pNear->pColset,
+              &p->pIter
+          );
+          assert( (rc==SQLITE_OK)==(p->pIter!=0) );
+          if( rc!=SQLITE_OK ) return rc;
+          if( 0==sqlite3Fts5IterEof(p->pIter) ){
+            bHit = 1;
+          }
+        }
+
+        if( bHit==0 ){
+          pNode->bEof = 1;
+          return SQLITE_OK;
+        }
+      }
+    }
+  }
+
+  pNode->bEof = 0;
+  return SQLITE_OK;
+}
+
+/*
+** If pExpr is an ASC iterator, this function returns a value with the
+** same sign as:
+**
+**   (iLhs - iRhs)
+**
+** Otherwise, if this is a DESC iterator, the opposite is returned:
+**
+**   (iRhs - iLhs)
+*/
+static int fts5RowidCmp(
+  Fts5Expr *pExpr,
+  i64 iLhs,
+  i64 iRhs
+){
+  assert( pExpr->bDesc==0 || pExpr->bDesc==1 );
+  if( pExpr->bDesc==0 ){
+    if( iLhs<iRhs ) return -1;
+    return (iLhs > iRhs);
+  }else{
+    if( iLhs>iRhs ) return -1;
+    return (iLhs < iRhs);
+  }
+}
+
+static void fts5ExprSetEof(Fts5ExprNode *pNode){
+  int i;
+  pNode->bEof = 1;
+  pNode->bNomatch = 0;
+  for(i=0; i<pNode->nChild; i++){
+    fts5ExprSetEof(pNode->apChild[i]);
+  }
+}
+
+static void fts5ExprNodeZeroPoslist(Fts5ExprNode *pNode){
+  if( pNode->eType==FTS5_STRING || pNode->eType==FTS5_TERM ){
+    Fts5ExprNearset *pNear = pNode->pNear;
+    int i;
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      pPhrase->poslist.n = 0;
+    }
+  }else{
+    int i;
+    for(i=0; i<pNode->nChild; i++){
+      fts5ExprNodeZeroPoslist(pNode->apChild[i]);
+    }
+  }
+}
+
+
+
+/*
+** Compare the values currently indicated by the two nodes as follows:
+**
+**    res = (*p1) - (*p2)
+**
+** Nodes that point to values that come later in the iteration order are
+** considered to be larger. Nodes at EOF are the largest of all.
+**
+** This means that if the iteration order is ASC, then numerically larger
+** rowids are considered larger. Or if it is the default DESC, numerically
+** smaller rowids are larger.
+*/
+static int fts5NodeCompare(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *p1,
+  Fts5ExprNode *p2
+){
+  if( p2->bEof ) return -1;
+  if( p1->bEof ) return +1;
+  return fts5RowidCmp(pExpr, p1->iRowid, p2->iRowid);
+}
+
+/*
+** All individual term iterators in pNear are guaranteed to be valid when
+** this function is called. This function checks if all term iterators
+** point to the same rowid, and if not, advances them until they do.
+** If an EOF is reached before this happens, *pbEof is set to true before
+** returning.
+**
+** SQLITE_OK is returned if an error occurs, or an SQLite error code
+** otherwise. It is not considered an error code if an iterator reaches
+** EOF.
+*/
+static int fts5ExprNodeTest_STRING(
+  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
+  Fts5ExprNode *pNode
+){
+  Fts5ExprNearset *pNear = pNode->pNear;
+  Fts5ExprPhrase *pLeft = pNear->apPhrase[0];
+  int rc = SQLITE_OK;
+  i64 iLast;                      /* Lastest rowid any iterator points to */
+  int i, j;                       /* Phrase and token index, respectively */
+  int bMatch;                     /* True if all terms are at the same rowid */
+  const int bDesc = pExpr->bDesc;
+
+  /* Check that this node should not be FTS5_TERM */
+  assert( pNear->nPhrase>1
+       || pNear->apPhrase[0]->nTerm>1
+       || pNear->apPhrase[0]->aTerm[0].pSynonym
+       || pNear->apPhrase[0]->aTerm[0].bFirst
+  );
+
+  /* Initialize iLast, the "lastest" rowid any iterator points to. If the
+  ** iterator skips through rowids in the default ascending order, this means
+  ** the maximum rowid. Or, if the iterator is "ORDER BY rowid DESC", then it
+  ** means the minimum rowid.  */
+  if( pLeft->aTerm[0].pSynonym ){
+    iLast = fts5ExprSynonymRowid(&pLeft->aTerm[0], bDesc, 0);
+  }else{
+    iLast = pLeft->aTerm[0].pIter->iRowid;
+  }
+
+  do {
+    bMatch = 1;
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      for(j=0; j<pPhrase->nTerm; j++){
+        Fts5ExprTerm *pTerm = &pPhrase->aTerm[j];
+        if( pTerm->pSynonym ){
+          i64 iRowid = fts5ExprSynonymRowid(pTerm, bDesc, 0);
+          if( iRowid==iLast ) continue;
+          bMatch = 0;
+          if( fts5ExprSynonymAdvanceto(pTerm, bDesc, &iLast, &rc) ){
+            pNode->bNomatch = 0;
+            pNode->bEof = 1;
+            return rc;
+          }
+        }else{
+          Fts5IndexIter *pIter = pPhrase->aTerm[j].pIter;
+          if( pIter->iRowid==iLast ) continue;
+          bMatch = 0;
+          if( fts5ExprAdvanceto(pIter, bDesc, &iLast, &rc, &pNode->bEof) ){
+            return rc;
+          }
+        }
+      }
+    }
+  }while( bMatch==0 );
+
+  pNode->iRowid = iLast;
+  pNode->bNomatch = ((0==fts5ExprNearTest(&rc, pExpr, pNode)) && rc==SQLITE_OK);
+  assert( pNode->bEof==0 || pNode->bNomatch==0 );
+
+  return rc;
+}
+
+/*
+** Advance the first term iterator in the first phrase of pNear. Set output
+** variable *pbEof to true if it reaches EOF or if an error occurs.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int fts5ExprNodeNext_STRING(
+  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
+  Fts5ExprNode *pNode,            /* FTS5_STRING or FTS5_TERM node */
+  int bFromValid,
+  i64 iFrom
+){
+  Fts5ExprTerm *pTerm = &pNode->pNear->apPhrase[0]->aTerm[0];
+  int rc = SQLITE_OK;
+
+  pNode->bNomatch = 0;
+  if( pTerm->pSynonym ){
+    int bEof = 1;
+    Fts5ExprTerm *p;
+
+    /* Find the firstest rowid any synonym points to. */
+    i64 iRowid = fts5ExprSynonymRowid(pTerm, pExpr->bDesc, 0);
+
+    /* Advance each iterator that currently points to iRowid. Or, if iFrom
+    ** is valid - each iterator that points to a rowid before iFrom.  */
+    for(p=pTerm; p; p=p->pSynonym){
+      if( sqlite3Fts5IterEof(p->pIter)==0 ){
+        i64 ii = p->pIter->iRowid;
+        if( ii==iRowid
+         || (bFromValid && ii!=iFrom && (ii>iFrom)==pExpr->bDesc)
+        ){
+          if( bFromValid ){
+            rc = sqlite3Fts5IterNextFrom(p->pIter, iFrom);
+          }else{
+            rc = sqlite3Fts5IterNext(p->pIter);
+          }
+          if( rc!=SQLITE_OK ) break;
+          if( sqlite3Fts5IterEof(p->pIter)==0 ){
+            bEof = 0;
+          }
+        }else{
+          bEof = 0;
+        }
+      }
+    }
+
+    /* Set the EOF flag if either all synonym iterators are at EOF or an
+    ** error has occurred.  */
+    pNode->bEof = (rc || bEof);
+  }else{
+    Fts5IndexIter *pIter = pTerm->pIter;
+
+    assert( Fts5NodeIsString(pNode) );
+    if( bFromValid ){
+      rc = sqlite3Fts5IterNextFrom(pIter, iFrom);
+    }else{
+      rc = sqlite3Fts5IterNext(pIter);
+    }
+
+    pNode->bEof = (rc || sqlite3Fts5IterEof(pIter));
+  }
+
+  if( pNode->bEof==0 ){
+    assert( rc==SQLITE_OK );
+    rc = fts5ExprNodeTest_STRING(pExpr, pNode);
+  }
+
+  return rc;
+}
+
+
+static int fts5ExprNodeTest_TERM(
+  Fts5Expr *pExpr,                /* Expression that pNear is a part of */
+  Fts5ExprNode *pNode             /* The "NEAR" node (FTS5_TERM) */
+){
+  /* As this "NEAR" object is actually a single phrase that consists
+  ** of a single term only, grab pointers into the poslist managed by the
+  ** fts5_index.c iterator object. This is much faster than synthesizing
+  ** a new poslist the way we have to for more complicated phrase or NEAR
+  ** expressions.  */
+  Fts5ExprPhrase *pPhrase = pNode->pNear->apPhrase[0];
+  Fts5IndexIter *pIter = pPhrase->aTerm[0].pIter;
+
+  assert( pNode->eType==FTS5_TERM );
+  assert( pNode->pNear->nPhrase==1 && pPhrase->nTerm==1 );
+  assert( pPhrase->aTerm[0].pSynonym==0 );
+
+  pPhrase->poslist.n = pIter->nData;
+  if( pExpr->pConfig->eDetail==FTS5_DETAIL_FULL ){
+    pPhrase->poslist.p = (u8*)pIter->pData;
+  }
+  pNode->iRowid = pIter->iRowid;
+  pNode->bNomatch = (pPhrase->poslist.n==0);
+  return SQLITE_OK;
+}
+
+/*
+** xNext() method for a node of type FTS5_TERM.
+*/
+static int fts5ExprNodeNext_TERM(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode,
+  int bFromValid,
+  i64 iFrom
+){
+  int rc;
+  Fts5IndexIter *pIter = pNode->pNear->apPhrase[0]->aTerm[0].pIter;
+
+  assert( pNode->bEof==0 );
+  if( bFromValid ){
+    rc = sqlite3Fts5IterNextFrom(pIter, iFrom);
+  }else{
+    rc = sqlite3Fts5IterNext(pIter);
+  }
+  if( rc==SQLITE_OK && sqlite3Fts5IterEof(pIter)==0 ){
+    rc = fts5ExprNodeTest_TERM(pExpr, pNode);
+  }else{
+    pNode->bEof = 1;
+    pNode->bNomatch = 0;
+  }
+  return rc;
+}
+
+static void fts5ExprNodeTest_OR(
+  Fts5Expr *pExpr,                /* Expression of which pNode is a part */
+  Fts5ExprNode *pNode             /* Expression node to test */
+){
+  Fts5ExprNode *pNext = pNode->apChild[0];
+  int i;
+
+  for(i=1; i<pNode->nChild; i++){
+    Fts5ExprNode *pChild = pNode->apChild[i];
+    int cmp = fts5NodeCompare(pExpr, pNext, pChild);
+    if( cmp>0 || (cmp==0 && pChild->bNomatch==0) ){
+      pNext = pChild;
+    }
+  }
+  pNode->iRowid = pNext->iRowid;
+  pNode->bEof = pNext->bEof;
+  pNode->bNomatch = pNext->bNomatch;
+}
+
+static int fts5ExprNodeNext_OR(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode,
+  int bFromValid,
+  i64 iFrom
+){
+  int i;
+  i64 iLast = pNode->iRowid;
+
+  for(i=0; i<pNode->nChild; i++){
+    Fts5ExprNode *p1 = pNode->apChild[i];
+    assert( p1->bEof || fts5RowidCmp(pExpr, p1->iRowid, iLast)>=0 );
+    if( p1->bEof==0 ){
+      if( (p1->iRowid==iLast)
+       || (bFromValid && fts5RowidCmp(pExpr, p1->iRowid, iFrom)<0)
+      ){
+        int rc = fts5ExprNodeNext(pExpr, p1, bFromValid, iFrom);
+        if( rc!=SQLITE_OK ){
+          pNode->bNomatch = 0;
+          return rc;
+        }
+      }
+    }
+  }
+
+  fts5ExprNodeTest_OR(pExpr, pNode);
+  return SQLITE_OK;
+}
+
+/*
+** Argument pNode is an FTS5_AND node.
+*/
+static int fts5ExprNodeTest_AND(
+  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
+  Fts5ExprNode *pAnd              /* FTS5_AND node to advance */
+){
+  int iChild;
+  i64 iLast = pAnd->iRowid;
+  int rc = SQLITE_OK;
+  int bMatch;
+
+  assert( pAnd->bEof==0 );
+  do {
+    pAnd->bNomatch = 0;
+    bMatch = 1;
+    for(iChild=0; iChild<pAnd->nChild; iChild++){
+      Fts5ExprNode *pChild = pAnd->apChild[iChild];
+      int cmp = fts5RowidCmp(pExpr, iLast, pChild->iRowid);
+      if( cmp>0 ){
+        /* Advance pChild until it points to iLast or laster */
+        rc = fts5ExprNodeNext(pExpr, pChild, 1, iLast);
+        if( rc!=SQLITE_OK ){
+          pAnd->bNomatch = 0;
+          return rc;
+        }
+      }
+
+      /* If the child node is now at EOF, so is the parent AND node. Otherwise,
+      ** the child node is guaranteed to have advanced at least as far as
+      ** rowid iLast. So if it is not at exactly iLast, pChild->iRowid is the
+      ** new lastest rowid seen so far.  */
+      assert( pChild->bEof || fts5RowidCmp(pExpr, iLast, pChild->iRowid)<=0 );
+      if( pChild->bEof ){
+        fts5ExprSetEof(pAnd);
+        bMatch = 1;
+        break;
+      }else if( iLast!=pChild->iRowid ){
+        bMatch = 0;
+        iLast = pChild->iRowid;
+      }
+
+      if( pChild->bNomatch ){
+        pAnd->bNomatch = 1;
+      }
+    }
+  }while( bMatch==0 );
+
+  if( pAnd->bNomatch && pAnd!=pExpr->pRoot ){
+    fts5ExprNodeZeroPoslist(pAnd);
+  }
+  pAnd->iRowid = iLast;
+  return SQLITE_OK;
+}
+
+static int fts5ExprNodeNext_AND(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode,
+  int bFromValid,
+  i64 iFrom
+){
+  int rc = fts5ExprNodeNext(pExpr, pNode->apChild[0], bFromValid, iFrom);
+  if( rc==SQLITE_OK ){
+    rc = fts5ExprNodeTest_AND(pExpr, pNode);
+  }else{
+    pNode->bNomatch = 0;
+  }
+  return rc;
+}
+
+static int fts5ExprNodeTest_NOT(
+  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
+  Fts5ExprNode *pNode             /* FTS5_NOT node to advance */
+){
+  int rc = SQLITE_OK;
+  Fts5ExprNode *p1 = pNode->apChild[0];
+  Fts5ExprNode *p2 = pNode->apChild[1];
+  assert( pNode->nChild==2 );
+
+  while( rc==SQLITE_OK && p1->bEof==0 ){
+    int cmp = fts5NodeCompare(pExpr, p1, p2);
+    if( cmp>0 ){
+      rc = fts5ExprNodeNext(pExpr, p2, 1, p1->iRowid);
+      cmp = fts5NodeCompare(pExpr, p1, p2);
+    }
+    assert( rc!=SQLITE_OK || cmp<=0 );
+    if( cmp || p2->bNomatch ) break;
+    rc = fts5ExprNodeNext(pExpr, p1, 0, 0);
+  }
+  pNode->bEof = p1->bEof;
+  pNode->bNomatch = p1->bNomatch;
+  pNode->iRowid = p1->iRowid;
+  if( p1->bEof ){
+    fts5ExprNodeZeroPoslist(p2);
+  }
+  return rc;
+}
+
+static int fts5ExprNodeNext_NOT(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode,
+  int bFromValid,
+  i64 iFrom
+){
+  int rc = fts5ExprNodeNext(pExpr, pNode->apChild[0], bFromValid, iFrom);
+  if( rc==SQLITE_OK ){
+    rc = fts5ExprNodeTest_NOT(pExpr, pNode);
+  }
+  if( rc!=SQLITE_OK ){
+    pNode->bNomatch = 0;
+  }
+  return rc;
+}
+
+/*
+** If pNode currently points to a match, this function returns SQLITE_OK
+** without modifying it. Otherwise, pNode is advanced until it does point
+** to a match or EOF is reached.
+*/
+static int fts5ExprNodeTest(
+  Fts5Expr *pExpr,                /* Expression of which pNode is a part */
+  Fts5ExprNode *pNode             /* Expression node to test */
+){
+  int rc = SQLITE_OK;
+  if( pNode->bEof==0 ){
+    switch( pNode->eType ){
+
+      case FTS5_STRING: {
+        rc = fts5ExprNodeTest_STRING(pExpr, pNode);
+        break;
+      }
+
+      case FTS5_TERM: {
+        rc = fts5ExprNodeTest_TERM(pExpr, pNode);
+        break;
+      }
+
+      case FTS5_AND: {
+        rc = fts5ExprNodeTest_AND(pExpr, pNode);
+        break;
+      }
+
+      case FTS5_OR: {
+        fts5ExprNodeTest_OR(pExpr, pNode);
+        break;
+      }
+
+      default: assert( pNode->eType==FTS5_NOT ); {
+        rc = fts5ExprNodeTest_NOT(pExpr, pNode);
+        break;
+      }
+    }
+  }
+  return rc;
+}
+
+
+/*
+** Set node pNode, which is part of expression pExpr, to point to the first
+** match. If there are no matches, set the Node.bEof flag to indicate EOF.
+**
+** Return an SQLite error code if an error occurs, or SQLITE_OK otherwise.
+** It is not an error if there are no matches.
+*/
+static int fts5ExprNodeFirst(Fts5Expr *pExpr, Fts5ExprNode *pNode){
+  int rc = SQLITE_OK;
+  pNode->bEof = 0;
+  pNode->bNomatch = 0;
+
+  if( Fts5NodeIsString(pNode) ){
+    /* Initialize all term iterators in the NEAR object. */
+    rc = fts5ExprNearInitAll(pExpr, pNode);
+  }else if( pNode->xNext==0 ){
+    pNode->bEof = 1;
+  }else{
+    int i;
+    int nEof = 0;
+    for(i=0; i<pNode->nChild && rc==SQLITE_OK; i++){
+      Fts5ExprNode *pChild = pNode->apChild[i];
+      rc = fts5ExprNodeFirst(pExpr, pNode->apChild[i]);
+      assert( pChild->bEof==0 || pChild->bEof==1 );
+      nEof += pChild->bEof;
+    }
+    pNode->iRowid = pNode->apChild[0]->iRowid;
+
+    switch( pNode->eType ){
+      case FTS5_AND:
+        if( nEof>0 ) fts5ExprSetEof(pNode);
+        break;
+
+      case FTS5_OR:
+        if( pNode->nChild==nEof ) fts5ExprSetEof(pNode);
+        break;
+
+      default:
+        assert( pNode->eType==FTS5_NOT );
+        pNode->bEof = pNode->apChild[0]->bEof;
+        break;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts5ExprNodeTest(pExpr, pNode);
+  }
+  return rc;
+}
+
+
+/*
+** Begin iterating through the set of documents in index pIdx matched by
+** the MATCH expression passed as the first argument. If the "bDesc"
+** parameter is passed a non-zero value, iteration is in descending rowid
+** order. Or, if it is zero, in ascending order.
+**
+** If iterating in ascending rowid order (bDesc==0), the first document
+** visited is that with the smallest rowid that is larger than or equal
+** to parameter iFirst. Or, if iterating in ascending order (bDesc==1),
+** then the first document visited must have a rowid smaller than or
+** equal to iFirst.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise. It
+** is not considered an error if the query does not match any documents.
+*/
+static int sqlite3Fts5ExprFirst(Fts5Expr *p, Fts5Index *pIdx, i64 iFirst, int bDesc){
+  Fts5ExprNode *pRoot = p->pRoot;
+  int rc;                         /* Return code */
+
+  p->pIndex = pIdx;
+  p->bDesc = bDesc;
+  rc = fts5ExprNodeFirst(p, pRoot);
+
+  /* If not at EOF but the current rowid occurs earlier than iFirst in
+  ** the iteration order, move to document iFirst or later. */
+  if( rc==SQLITE_OK
+   && 0==pRoot->bEof
+   && fts5RowidCmp(p, pRoot->iRowid, iFirst)<0
+  ){
+    rc = fts5ExprNodeNext(p, pRoot, 1, iFirst);
+  }
+
+  /* If the iterator is not at a real match, skip forward until it is. */
+  while( pRoot->bNomatch && rc==SQLITE_OK ){
+    assert( pRoot->bEof==0 );
+    rc = fts5ExprNodeNext(p, pRoot, 0, 0);
+  }
+  return rc;
+}
+
+/*
+** Move to the next document
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise. It
+** is not considered an error if the query does not match any documents.
+*/
+static int sqlite3Fts5ExprNext(Fts5Expr *p, i64 iLast){
+  int rc;
+  Fts5ExprNode *pRoot = p->pRoot;
+  assert( pRoot->bEof==0 && pRoot->bNomatch==0 );
+  do {
+    rc = fts5ExprNodeNext(p, pRoot, 0, 0);
+    assert( pRoot->bNomatch==0 || (rc==SQLITE_OK && pRoot->bEof==0) );
+  }while( pRoot->bNomatch );
+  if( fts5RowidCmp(p, pRoot->iRowid, iLast)>0 ){
+    pRoot->bEof = 1;
+  }
+  return rc;
+}
+
+static int sqlite3Fts5ExprEof(Fts5Expr *p){
+  return p->pRoot->bEof;
+}
+
+static i64 sqlite3Fts5ExprRowid(Fts5Expr *p){
+  return p->pRoot->iRowid;
+}
+
+static int fts5ParseStringFromToken(Fts5Token *pToken, char **pz){
+  int rc = SQLITE_OK;
+  *pz = sqlite3Fts5Strndup(&rc, pToken->p, pToken->n);
+  return rc;
+}
+
+/*
+** Free the phrase object passed as the only argument.
+*/
+static void fts5ExprPhraseFree(Fts5ExprPhrase *pPhrase){
+  if( pPhrase ){
+    int i;
+    for(i=0; i<pPhrase->nTerm; i++){
+      Fts5ExprTerm *pSyn;
+      Fts5ExprTerm *pNext;
+      Fts5ExprTerm *pTerm = &pPhrase->aTerm[i];
+      sqlite3_free(pTerm->pTerm);
+      sqlite3Fts5IterClose(pTerm->pIter);
+      for(pSyn=pTerm->pSynonym; pSyn; pSyn=pNext){
+        pNext = pSyn->pSynonym;
+        sqlite3Fts5IterClose(pSyn->pIter);
+        fts5BufferFree((Fts5Buffer*)&pSyn[1]);
+        sqlite3_free(pSyn);
+      }
+    }
+    if( pPhrase->poslist.nSpace>0 ) fts5BufferFree(&pPhrase->poslist);
+    sqlite3_free(pPhrase);
+  }
+}
+
+/*
+** Set the "bFirst" flag on the first token of the phrase passed as the
+** only argument.
+*/
+static void sqlite3Fts5ParseSetCaret(Fts5ExprPhrase *pPhrase){
+  if( pPhrase && pPhrase->nTerm ){
+    pPhrase->aTerm[0].bFirst = 1;
+  }
+}
+
+/*
+** If argument pNear is NULL, then a new Fts5ExprNearset object is allocated
+** and populated with pPhrase. Or, if pNear is not NULL, phrase pPhrase is
+** appended to it and the results returned.
+**
+** If an OOM error occurs, both the pNear and pPhrase objects are freed and
+** NULL returned.
+*/
+static Fts5ExprNearset *sqlite3Fts5ParseNearset(
+  Fts5Parse *pParse,              /* Parse context */
+  Fts5ExprNearset *pNear,         /* Existing nearset, or NULL */
+  Fts5ExprPhrase *pPhrase         /* Recently parsed phrase */
+){
+  const int SZALLOC = 8;
+  Fts5ExprNearset *pRet = 0;
+
+  if( pParse->rc==SQLITE_OK ){
+    if( pNear==0 ){
+      sqlite3_int64 nByte;
+      nByte = sizeof(Fts5ExprNearset) + SZALLOC * sizeof(Fts5ExprPhrase*);
+      pRet = sqlite3_malloc64(nByte);
+      if( pRet==0 ){
+        pParse->rc = SQLITE_NOMEM;
+      }else{
+        memset(pRet, 0, (size_t)nByte);
+      }
+    }else if( (pNear->nPhrase % SZALLOC)==0 ){
+      int nNew = pNear->nPhrase + SZALLOC;
+      sqlite3_int64 nByte;
+
+      nByte = sizeof(Fts5ExprNearset) + nNew * sizeof(Fts5ExprPhrase*);
+      pRet = (Fts5ExprNearset*)sqlite3_realloc64(pNear, nByte);
+      if( pRet==0 ){
+        pParse->rc = SQLITE_NOMEM;
+      }
+    }else{
+      pRet = pNear;
+    }
+  }
+
+  if( pRet==0 ){
+    assert( pParse->rc!=SQLITE_OK );
+    sqlite3Fts5ParseNearsetFree(pNear);
+    sqlite3Fts5ParsePhraseFree(pPhrase);
+  }else{
+    if( pRet->nPhrase>0 ){
+      Fts5ExprPhrase *pLast = pRet->apPhrase[pRet->nPhrase-1];
+      assert( pParse!=0 );
+      assert( pParse->apPhrase!=0 );
+      assert( pParse->nPhrase>=2 );
+      assert( pLast==pParse->apPhrase[pParse->nPhrase-2] );
+      if( pPhrase->nTerm==0 ){
+        fts5ExprPhraseFree(pPhrase);
+        pRet->nPhrase--;
+        pParse->nPhrase--;
+        pPhrase = pLast;
+      }else if( pLast->nTerm==0 ){
+        fts5ExprPhraseFree(pLast);
+        pParse->apPhrase[pParse->nPhrase-2] = pPhrase;
+        pParse->nPhrase--;
+        pRet->nPhrase--;
+      }
+    }
+    pRet->apPhrase[pRet->nPhrase++] = pPhrase;
+  }
+  return pRet;
+}
+
+typedef struct TokenCtx TokenCtx;
+struct TokenCtx {
+  Fts5ExprPhrase *pPhrase;
+  Fts5Config *pConfig;
+  int rc;
+};
+
+/*
+** Callback for tokenizing terms used by ParseTerm().
+*/
+static int fts5ParseTokenize(
+  void *pContext,                 /* Pointer to Fts5InsertCtx object */
+  int tflags,                     /* Mask of FTS5_TOKEN_* flags */
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iUnused1,                   /* Start offset of token */
+  int iUnused2                    /* End offset of token */
+){
+  int rc = SQLITE_OK;
+  const int SZALLOC = 8;
+  TokenCtx *pCtx = (TokenCtx*)pContext;
+  Fts5ExprPhrase *pPhrase = pCtx->pPhrase;
+
+  UNUSED_PARAM2(iUnused1, iUnused2);
+
+  /* If an error has already occurred, this is a no-op */
+  if( pCtx->rc!=SQLITE_OK ) return pCtx->rc;
+  if( nToken>FTS5_MAX_TOKEN_SIZE ) nToken = FTS5_MAX_TOKEN_SIZE;
+
+  if( pPhrase && pPhrase->nTerm>0 && (tflags & FTS5_TOKEN_COLOCATED) ){
+    Fts5ExprTerm *pSyn;
+    sqlite3_int64 nByte = sizeof(Fts5ExprTerm) + sizeof(Fts5Buffer) + nToken+1;
+    pSyn = (Fts5ExprTerm*)sqlite3_malloc64(nByte);
+    if( pSyn==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pSyn, 0, (size_t)nByte);
+      pSyn->pTerm = ((char*)pSyn) + sizeof(Fts5ExprTerm) + sizeof(Fts5Buffer);
+      pSyn->nFullTerm = pSyn->nQueryTerm = nToken;
+      if( pCtx->pConfig->bTokendata ){
+        pSyn->nQueryTerm = (int)strlen(pSyn->pTerm);
+      }
+      memcpy(pSyn->pTerm, pToken, nToken);
+      pSyn->pSynonym = pPhrase->aTerm[pPhrase->nTerm-1].pSynonym;
+      pPhrase->aTerm[pPhrase->nTerm-1].pSynonym = pSyn;
+    }
+  }else{
+    Fts5ExprTerm *pTerm;
+    if( pPhrase==0 || (pPhrase->nTerm % SZALLOC)==0 ){
+      Fts5ExprPhrase *pNew;
+      int nNew = SZALLOC + (pPhrase ? pPhrase->nTerm : 0);
+
+      pNew = (Fts5ExprPhrase*)sqlite3_realloc64(pPhrase,
+          sizeof(Fts5ExprPhrase) + sizeof(Fts5ExprTerm) * nNew
+      );
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        if( pPhrase==0 ) memset(pNew, 0, sizeof(Fts5ExprPhrase));
+        pCtx->pPhrase = pPhrase = pNew;
+        pNew->nTerm = nNew - SZALLOC;
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      pTerm = &pPhrase->aTerm[pPhrase->nTerm++];
+      memset(pTerm, 0, sizeof(Fts5ExprTerm));
+      pTerm->pTerm = sqlite3Fts5Strndup(&rc, pToken, nToken);
+      pTerm->nFullTerm = pTerm->nQueryTerm = nToken;
+      if( pCtx->pConfig->bTokendata && rc==SQLITE_OK ){
+        pTerm->nQueryTerm = (int)strlen(pTerm->pTerm);
+      }
+    }
+  }
+
+  pCtx->rc = rc;
+  return rc;
+}
+
+
+/*
+** Free the phrase object passed as the only argument.
+*/
+static void sqlite3Fts5ParsePhraseFree(Fts5ExprPhrase *pPhrase){
+  fts5ExprPhraseFree(pPhrase);
+}
+
+/*
+** Free the phrase object passed as the second argument.
+*/
+static void sqlite3Fts5ParseNearsetFree(Fts5ExprNearset *pNear){
+  if( pNear ){
+    int i;
+    for(i=0; i<pNear->nPhrase; i++){
+      fts5ExprPhraseFree(pNear->apPhrase[i]);
+    }
+    sqlite3_free(pNear->pColset);
+    sqlite3_free(pNear);
+  }
+}
+
+static void sqlite3Fts5ParseFinished(Fts5Parse *pParse, Fts5ExprNode *p){
+  assert( pParse->pExpr==0 );
+  pParse->pExpr = p;
+}
+
+static int parseGrowPhraseArray(Fts5Parse *pParse){
+  if( (pParse->nPhrase % 8)==0 ){
+    sqlite3_int64 nByte = sizeof(Fts5ExprPhrase*) * (pParse->nPhrase + 8);
+    Fts5ExprPhrase **apNew;
+    apNew = (Fts5ExprPhrase**)sqlite3_realloc64(pParse->apPhrase, nByte);
+    if( apNew==0 ){
+      pParse->rc = SQLITE_NOMEM;
+      return SQLITE_NOMEM;
+    }
+    pParse->apPhrase = apNew;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is called by the parser to process a string token. The
+** string may or may not be quoted. In any case it is tokenized and a
+** phrase object consisting of all tokens returned.
+*/
+static Fts5ExprPhrase *sqlite3Fts5ParseTerm(
+  Fts5Parse *pParse,              /* Parse context */
+  Fts5ExprPhrase *pAppend,        /* Phrase to append to */
+  Fts5Token *pToken,              /* String to tokenize */
+  int bPrefix                     /* True if there is a trailing "*" */
+){
+  Fts5Config *pConfig = pParse->pConfig;
+  TokenCtx sCtx;                  /* Context object passed to callback */
+  int rc;                         /* Tokenize return code */
+  char *z = 0;
+
+  memset(&sCtx, 0, sizeof(TokenCtx));
+  sCtx.pPhrase = pAppend;
+  sCtx.pConfig = pConfig;
+
+  rc = fts5ParseStringFromToken(pToken, &z);
+  if( rc==SQLITE_OK ){
+    int flags = FTS5_TOKENIZE_QUERY | (bPrefix ? FTS5_TOKENIZE_PREFIX : 0);
+    int n;
+    sqlite3Fts5Dequote(z);
+    n = (int)strlen(z);
+    rc = sqlite3Fts5Tokenize(pConfig, flags, z, n, &sCtx, fts5ParseTokenize);
+  }
+  sqlite3_free(z);
+  if( rc || (rc = sCtx.rc) ){
+    pParse->rc = rc;
+    fts5ExprPhraseFree(sCtx.pPhrase);
+    sCtx.pPhrase = 0;
+  }else{
+
+    if( pAppend==0 ){
+      if( parseGrowPhraseArray(pParse) ){
+        fts5ExprPhraseFree(sCtx.pPhrase);
+        return 0;
+      }
+      pParse->nPhrase++;
+    }
+
+    if( sCtx.pPhrase==0 ){
+      /* This happens when parsing a token or quoted phrase that contains
+      ** no token characters at all. (e.g ... MATCH '""'). */
+      sCtx.pPhrase = sqlite3Fts5MallocZero(&pParse->rc, sizeof(Fts5ExprPhrase));
+    }else if( sCtx.pPhrase->nTerm ){
+      sCtx.pPhrase->aTerm[sCtx.pPhrase->nTerm-1].bPrefix = (u8)bPrefix;
+    }
+    assert( pParse->apPhrase!=0 );
+    pParse->apPhrase[pParse->nPhrase-1] = sCtx.pPhrase;
+  }
+
+  return sCtx.pPhrase;
+}
+
+/*
+** Create a new FTS5 expression by cloning phrase iPhrase of the
+** expression passed as the second argument.
+*/
+static int sqlite3Fts5ExprClonePhrase(
+  Fts5Expr *pExpr,
+  int iPhrase,
+  Fts5Expr **ppNew
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5ExprPhrase *pOrig = 0;      /* The phrase extracted from pExpr */
+  Fts5Expr *pNew = 0;             /* Expression to return via *ppNew */
+  TokenCtx sCtx = {0,0,0};        /* Context object for fts5ParseTokenize */
+  if( !pExpr || iPhrase<0 || iPhrase>=pExpr->nPhrase ){
+    rc = SQLITE_RANGE;
+  }else{
+    pOrig = pExpr->apExprPhrase[iPhrase];
+    pNew = (Fts5Expr*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Expr));
+  }
+  if( rc==SQLITE_OK ){
+    pNew->apExprPhrase = (Fts5ExprPhrase**)sqlite3Fts5MallocZero(&rc,
+        sizeof(Fts5ExprPhrase*));
+  }
+  if( rc==SQLITE_OK ){
+    pNew->pRoot = (Fts5ExprNode*)sqlite3Fts5MallocZero(&rc,
+        sizeof(Fts5ExprNode));
+  }
+  if( rc==SQLITE_OK ){
+    pNew->pRoot->pNear = (Fts5ExprNearset*)sqlite3Fts5MallocZero(&rc,
+        sizeof(Fts5ExprNearset) + sizeof(Fts5ExprPhrase*));
+  }
+  if( rc==SQLITE_OK && ALWAYS(pOrig!=0) ){
+    Fts5Colset *pColsetOrig = pOrig->pNode->pNear->pColset;
+    if( pColsetOrig ){
+      sqlite3_int64 nByte;
+      Fts5Colset *pColset;
+      nByte = sizeof(Fts5Colset) + (pColsetOrig->nCol-1) * sizeof(int);
+      pColset = (Fts5Colset*)sqlite3Fts5MallocZero(&rc, nByte);
+      if( pColset ){
+        memcpy(pColset, pColsetOrig, (size_t)nByte);
+      }
+      pNew->pRoot->pNear->pColset = pColset;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( pOrig->nTerm ){
+      int i;                          /* Used to iterate through phrase terms */
+      sCtx.pConfig = pExpr->pConfig;
+      for(i=0; rc==SQLITE_OK && i<pOrig->nTerm; i++){
+        int tflags = 0;
+        Fts5ExprTerm *p;
+        for(p=&pOrig->aTerm[i]; p && rc==SQLITE_OK; p=p->pSynonym){
+          rc = fts5ParseTokenize((void*)&sCtx,tflags,p->pTerm,p->nFullTerm,0,0);
+          tflags = FTS5_TOKEN_COLOCATED;
+        }
+        if( rc==SQLITE_OK ){
+          sCtx.pPhrase->aTerm[i].bPrefix = pOrig->aTerm[i].bPrefix;
+          sCtx.pPhrase->aTerm[i].bFirst = pOrig->aTerm[i].bFirst;
+        }
+      }
+    }else{
+      /* This happens when parsing a token or quoted phrase that contains
+      ** no token characters at all. (e.g ... MATCH '""'). */
+      sCtx.pPhrase = sqlite3Fts5MallocZero(&rc, sizeof(Fts5ExprPhrase));
+    }
+  }
+
+  if( rc==SQLITE_OK && ALWAYS(sCtx.pPhrase) ){
+    /* All the allocations succeeded. Put the expression object together. */
+    pNew->pIndex = pExpr->pIndex;
+    pNew->pConfig = pExpr->pConfig;
+    pNew->nPhrase = 1;
+    pNew->apExprPhrase[0] = sCtx.pPhrase;
+    pNew->pRoot->pNear->apPhrase[0] = sCtx.pPhrase;
+    pNew->pRoot->pNear->nPhrase = 1;
+    sCtx.pPhrase->pNode = pNew->pRoot;
+
+    if( pOrig->nTerm==1
+     && pOrig->aTerm[0].pSynonym==0
+     && pOrig->aTerm[0].bFirst==0
+    ){
+      pNew->pRoot->eType = FTS5_TERM;
+      pNew->pRoot->xNext = fts5ExprNodeNext_TERM;
+    }else{
+      pNew->pRoot->eType = FTS5_STRING;
+      pNew->pRoot->xNext = fts5ExprNodeNext_STRING;
+    }
+  }else{
+    sqlite3Fts5ExprFree(pNew);
+    fts5ExprPhraseFree(sCtx.pPhrase);
+    pNew = 0;
+  }
+
+  *ppNew = pNew;
+  return rc;
+}
+
+
+/*
+** Token pTok has appeared in a MATCH expression where the NEAR operator
+** is expected. If token pTok does not contain "NEAR", store an error
+** in the pParse object.
+*/
+static void sqlite3Fts5ParseNear(Fts5Parse *pParse, Fts5Token *pTok){
+  if( pTok->n!=4 || memcmp("NEAR", pTok->p, 4) ){
+    sqlite3Fts5ParseError(
+        pParse, "fts5: syntax error near \"%.*s\"", pTok->n, pTok->p
+    );
+  }
+}
+
+static void sqlite3Fts5ParseSetDistance(
+  Fts5Parse *pParse,
+  Fts5ExprNearset *pNear,
+  Fts5Token *p
+){
+  if( pNear ){
+    int nNear = 0;
+    int i;
+    if( p->n ){
+      for(i=0; i<p->n; i++){
+        char c = (char)p->p[i];
+        if( c<'0' || c>'9' ){
+          sqlite3Fts5ParseError(
+              pParse, "expected integer, got \"%.*s\"", p->n, p->p
+              );
+          return;
+        }
+        nNear = nNear * 10 + (p->p[i] - '0');
+      }
+    }else{
+      nNear = FTS5_DEFAULT_NEARDIST;
+    }
+    pNear->nNear = nNear;
+  }
+}
+
+/*
+** The second argument passed to this function may be NULL, or it may be
+** an existing Fts5Colset object. This function returns a pointer to
+** a new colset object containing the contents of (p) with new value column
+** number iCol appended.
+**
+** If an OOM error occurs, store an error code in pParse and return NULL.
+** The old colset object (if any) is not freed in this case.
+*/
+static Fts5Colset *fts5ParseColset(
+  Fts5Parse *pParse,              /* Store SQLITE_NOMEM here if required */
+  Fts5Colset *p,                  /* Existing colset object */
+  int iCol                        /* New column to add to colset object */
+){
+  int nCol = p ? p->nCol : 0;     /* Num. columns already in colset object */
+  Fts5Colset *pNew;               /* New colset object to return */
+
+  assert( pParse->rc==SQLITE_OK );
+  assert( iCol>=0 && iCol<pParse->pConfig->nCol );
+
+  pNew = sqlite3_realloc64(p, sizeof(Fts5Colset) + sizeof(int)*nCol);
+  if( pNew==0 ){
+    pParse->rc = SQLITE_NOMEM;
+  }else{
+    int *aiCol = pNew->aiCol;
+    int i, j;
+    for(i=0; i<nCol; i++){
+      if( aiCol[i]==iCol ) return pNew;
+      if( aiCol[i]>iCol ) break;
+    }
+    for(j=nCol; j>i; j--){
+      aiCol[j] = aiCol[j-1];
+    }
+    aiCol[i] = iCol;
+    pNew->nCol = nCol+1;
+
+#ifndef NDEBUG
+    /* Check that the array is in order and contains no duplicate entries. */
+    for(i=1; i<pNew->nCol; i++) assert( pNew->aiCol[i]>pNew->aiCol[i-1] );
+#endif
+  }
+
+  return pNew;
+}
+
+/*
+** Allocate and return an Fts5Colset object specifying the inverse of
+** the colset passed as the second argument. Free the colset passed
+** as the second argument before returning.
+*/
+static Fts5Colset *sqlite3Fts5ParseColsetInvert(Fts5Parse *pParse, Fts5Colset *p){
+  Fts5Colset *pRet;
+  int nCol = pParse->pConfig->nCol;
+
+  pRet = (Fts5Colset*)sqlite3Fts5MallocZero(&pParse->rc,
+      sizeof(Fts5Colset) + sizeof(int)*nCol
+  );
+  if( pRet ){
+    int i;
+    int iOld = 0;
+    for(i=0; i<nCol; i++){
+      if( iOld>=p->nCol || p->aiCol[iOld]!=i ){
+        pRet->aiCol[pRet->nCol++] = i;
+      }else{
+        iOld++;
+      }
+    }
+  }
+
+  sqlite3_free(p);
+  return pRet;
+}
+
+static Fts5Colset *sqlite3Fts5ParseColset(
+  Fts5Parse *pParse,              /* Store SQLITE_NOMEM here if required */
+  Fts5Colset *pColset,            /* Existing colset object */
+  Fts5Token *p
+){
+  Fts5Colset *pRet = 0;
+  int iCol;
+  char *z;                        /* Dequoted copy of token p */
+
+  z = sqlite3Fts5Strndup(&pParse->rc, p->p, p->n);
+  if( pParse->rc==SQLITE_OK ){
+    Fts5Config *pConfig = pParse->pConfig;
+    sqlite3Fts5Dequote(z);
+    for(iCol=0; iCol<pConfig->nCol; iCol++){
+      if( 0==sqlite3_stricmp(pConfig->azCol[iCol], z) ) break;
+    }
+    if( iCol==pConfig->nCol ){
+      sqlite3Fts5ParseError(pParse, "no such column: %s", z);
+    }else{
+      pRet = fts5ParseColset(pParse, pColset, iCol);
+    }
+    sqlite3_free(z);
+  }
+
+  if( pRet==0 ){
+    assert( pParse->rc!=SQLITE_OK );
+    sqlite3_free(pColset);
+  }
+
+  return pRet;
+}
+
+/*
+** If argument pOrig is NULL, or if (*pRc) is set to anything other than
+** SQLITE_OK when this function is called, NULL is returned.
+**
+** Otherwise, a copy of (*pOrig) is made into memory obtained from
+** sqlite3Fts5MallocZero() and a pointer to it returned. If the allocation
+** fails, (*pRc) is set to SQLITE_NOMEM and NULL is returned.
+*/
+static Fts5Colset *fts5CloneColset(int *pRc, Fts5Colset *pOrig){
+  Fts5Colset *pRet;
+  if( pOrig ){
+    sqlite3_int64 nByte = sizeof(Fts5Colset) + (pOrig->nCol-1) * sizeof(int);
+    pRet = (Fts5Colset*)sqlite3Fts5MallocZero(pRc, nByte);
+    if( pRet ){
+      memcpy(pRet, pOrig, (size_t)nByte);
+    }
+  }else{
+    pRet = 0;
+  }
+  return pRet;
+}
+
+/*
+** Remove from colset pColset any columns that are not also in colset pMerge.
+*/
+static void fts5MergeColset(Fts5Colset *pColset, Fts5Colset *pMerge){
+  int iIn = 0;          /* Next input in pColset */
+  int iMerge = 0;       /* Next input in pMerge */
+  int iOut = 0;         /* Next output slot in pColset */
+
+  while( iIn<pColset->nCol && iMerge<pMerge->nCol ){
+    int iDiff = pColset->aiCol[iIn] - pMerge->aiCol[iMerge];
+    if( iDiff==0 ){
+      pColset->aiCol[iOut++] = pMerge->aiCol[iMerge];
+      iMerge++;
+      iIn++;
+    }else if( iDiff>0 ){
+      iMerge++;
+    }else{
+      iIn++;
+    }
+  }
+  pColset->nCol = iOut;
+}
+
+/*
+** Recursively apply colset pColset to expression node pNode and all of
+** its decendents. If (*ppFree) is not NULL, it contains a spare copy
+** of pColset. This function may use the spare copy and set (*ppFree) to
+** zero, or it may create copies of pColset using fts5CloneColset().
+*/
+static void fts5ParseSetColset(
+  Fts5Parse *pParse,
+  Fts5ExprNode *pNode,
+  Fts5Colset *pColset,
+  Fts5Colset **ppFree
+){
+  if( pParse->rc==SQLITE_OK ){
+    assert( pNode->eType==FTS5_TERM || pNode->eType==FTS5_STRING
+         || pNode->eType==FTS5_AND  || pNode->eType==FTS5_OR
+         || pNode->eType==FTS5_NOT  || pNode->eType==FTS5_EOF
+    );
+    if( pNode->eType==FTS5_STRING || pNode->eType==FTS5_TERM ){
+      Fts5ExprNearset *pNear = pNode->pNear;
+      if( pNear->pColset ){
+        fts5MergeColset(pNear->pColset, pColset);
+        if( pNear->pColset->nCol==0 ){
+          pNode->eType = FTS5_EOF;
+          pNode->xNext = 0;
+        }
+      }else if( *ppFree ){
+        pNear->pColset = pColset;
+        *ppFree = 0;
+      }else{
+        pNear->pColset = fts5CloneColset(&pParse->rc, pColset);
+      }
+    }else{
+      int i;
+      assert( pNode->eType!=FTS5_EOF || pNode->nChild==0 );
+      for(i=0; i<pNode->nChild; i++){
+        fts5ParseSetColset(pParse, pNode->apChild[i], pColset, ppFree);
+      }
+    }
+  }
+}
+
+/*
+** Apply colset pColset to expression node pExpr and all of its descendents.
+*/
+static void sqlite3Fts5ParseSetColset(
+  Fts5Parse *pParse,
+  Fts5ExprNode *pExpr,
+  Fts5Colset *pColset
+){
+  Fts5Colset *pFree = pColset;
+  if( pParse->pConfig->eDetail==FTS5_DETAIL_NONE ){
+    sqlite3Fts5ParseError(pParse,
+        "fts5: column queries are not supported (detail=none)"
+    );
+  }else{
+    fts5ParseSetColset(pParse, pExpr, pColset, &pFree);
+  }
+  sqlite3_free(pFree);
+}
+
+static void fts5ExprAssignXNext(Fts5ExprNode *pNode){
+  switch( pNode->eType ){
+    case FTS5_STRING: {
+      Fts5ExprNearset *pNear = pNode->pNear;
+      if( pNear->nPhrase==1 && pNear->apPhrase[0]->nTerm==1
+       && pNear->apPhrase[0]->aTerm[0].pSynonym==0
+       && pNear->apPhrase[0]->aTerm[0].bFirst==0
+      ){
+        pNode->eType = FTS5_TERM;
+        pNode->xNext = fts5ExprNodeNext_TERM;
+      }else{
+        pNode->xNext = fts5ExprNodeNext_STRING;
+      }
+      break;
+    };
+
+    case FTS5_OR: {
+      pNode->xNext = fts5ExprNodeNext_OR;
+      break;
+    };
+
+    case FTS5_AND: {
+      pNode->xNext = fts5ExprNodeNext_AND;
+      break;
+    };
+
+    default: assert( pNode->eType==FTS5_NOT ); {
+      pNode->xNext = fts5ExprNodeNext_NOT;
+      break;
+    };
+  }
+}
+
+/*
+** Add pSub as a child of p.
+*/
+static void fts5ExprAddChildren(Fts5ExprNode *p, Fts5ExprNode *pSub){
+  int ii = p->nChild;
+  if( p->eType!=FTS5_NOT && pSub->eType==p->eType ){
+    int nByte = sizeof(Fts5ExprNode*) * pSub->nChild;
+    memcpy(&p->apChild[p->nChild], pSub->apChild, nByte);
+    p->nChild += pSub->nChild;
+    sqlite3_free(pSub);
+  }else{
+    p->apChild[p->nChild++] = pSub;
+  }
+  for( ; ii<p->nChild; ii++){
+    p->iHeight = MAX(p->iHeight, p->apChild[ii]->iHeight + 1);
+  }
+}
+
+/*
+** This function is used when parsing LIKE or GLOB patterns against
+** trigram indexes that specify either detail=column or detail=none.
+** It converts a phrase:
+**
+**     abc + def + ghi
+**
+** into an AND tree:
+**
+**     abc AND def AND ghi
+*/
+static Fts5ExprNode *fts5ParsePhraseToAnd(
+  Fts5Parse *pParse,
+  Fts5ExprNearset *pNear
+){
+  int nTerm = pNear->apPhrase[0]->nTerm;
+  int ii;
+  int nByte;
+  Fts5ExprNode *pRet;
+
+  assert( pNear->nPhrase==1 );
+  assert( pParse->bPhraseToAnd );
+
+  nByte = sizeof(Fts5ExprNode) + nTerm*sizeof(Fts5ExprNode*);
+  pRet = (Fts5ExprNode*)sqlite3Fts5MallocZero(&pParse->rc, nByte);
+  if( pRet ){
+    pRet->eType = FTS5_AND;
+    pRet->nChild = nTerm;
+    pRet->iHeight = 1;
+    fts5ExprAssignXNext(pRet);
+    pParse->nPhrase--;
+    for(ii=0; ii<nTerm; ii++){
+      Fts5ExprPhrase *pPhrase = (Fts5ExprPhrase*)sqlite3Fts5MallocZero(
+          &pParse->rc, sizeof(Fts5ExprPhrase)
+      );
+      if( pPhrase ){
+        if( parseGrowPhraseArray(pParse) ){
+          fts5ExprPhraseFree(pPhrase);
+        }else{
+          Fts5ExprTerm *p = &pNear->apPhrase[0]->aTerm[ii];
+          Fts5ExprTerm *pTo = &pPhrase->aTerm[0];
+          pParse->apPhrase[pParse->nPhrase++] = pPhrase;
+          pPhrase->nTerm = 1;
+          pTo->pTerm = sqlite3Fts5Strndup(&pParse->rc, p->pTerm, p->nFullTerm);
+          pTo->nQueryTerm = p->nQueryTerm;
+          pTo->nFullTerm = p->nFullTerm;
+          pRet->apChild[ii] = sqlite3Fts5ParseNode(pParse, FTS5_STRING,
+              0, 0, sqlite3Fts5ParseNearset(pParse, 0, pPhrase)
+          );
+        }
+      }
+    }
+
+    if( pParse->rc ){
+      sqlite3Fts5ParseNodeFree(pRet);
+      pRet = 0;
+    }else{
+      sqlite3Fts5ParseNearsetFree(pNear);
+    }
+  }
+
+  return pRet;
+}
+
+/*
+** Allocate and return a new expression object. If anything goes wrong (i.e.
+** OOM error), leave an error code in pParse and return NULL.
+*/
+static Fts5ExprNode *sqlite3Fts5ParseNode(
+  Fts5Parse *pParse,              /* Parse context */
+  int eType,                      /* FTS5_STRING, AND, OR or NOT */
+  Fts5ExprNode *pLeft,            /* Left hand child expression */
+  Fts5ExprNode *pRight,           /* Right hand child expression */
+  Fts5ExprNearset *pNear          /* For STRING expressions, the near cluster */
+){
+  Fts5ExprNode *pRet = 0;
+
+  if( pParse->rc==SQLITE_OK ){
+    int nChild = 0;               /* Number of children of returned node */
+    sqlite3_int64 nByte;          /* Bytes of space to allocate for this node */
+
+    assert( (eType!=FTS5_STRING && !pNear)
+         || (eType==FTS5_STRING && !pLeft && !pRight)
+    );
+    if( eType==FTS5_STRING && pNear==0 ) return 0;
+    if( eType!=FTS5_STRING && pLeft==0 ) return pRight;
+    if( eType!=FTS5_STRING && pRight==0 ) return pLeft;
+
+    if( eType==FTS5_STRING
+     && pParse->bPhraseToAnd
+     && pNear->apPhrase[0]->nTerm>1
+    ){
+      pRet = fts5ParsePhraseToAnd(pParse, pNear);
+    }else{
+      if( eType==FTS5_NOT ){
+        nChild = 2;
+      }else if( eType==FTS5_AND || eType==FTS5_OR ){
+        nChild = 2;
+        if( pLeft->eType==eType ) nChild += pLeft->nChild-1;
+        if( pRight->eType==eType ) nChild += pRight->nChild-1;
+      }
+
+      nByte = sizeof(Fts5ExprNode) + sizeof(Fts5ExprNode*)*(nChild-1);
+      pRet = (Fts5ExprNode*)sqlite3Fts5MallocZero(&pParse->rc, nByte);
+
+      if( pRet ){
+        pRet->eType = eType;
+        pRet->pNear = pNear;
+        fts5ExprAssignXNext(pRet);
+        if( eType==FTS5_STRING ){
+          int iPhrase;
+          for(iPhrase=0; iPhrase<pNear->nPhrase; iPhrase++){
+            pNear->apPhrase[iPhrase]->pNode = pRet;
+            if( pNear->apPhrase[iPhrase]->nTerm==0 ){
+              pRet->xNext = 0;
+              pRet->eType = FTS5_EOF;
+            }
+          }
+
+          if( pParse->pConfig->eDetail!=FTS5_DETAIL_FULL ){
+            Fts5ExprPhrase *pPhrase = pNear->apPhrase[0];
+            if( pNear->nPhrase!=1
+                || pPhrase->nTerm>1
+                || (pPhrase->nTerm>0 && pPhrase->aTerm[0].bFirst)
+              ){
+              sqlite3Fts5ParseError(pParse,
+                  "fts5: %s queries are not supported (detail!=full)",
+                  pNear->nPhrase==1 ? "phrase": "NEAR"
+              );
+              sqlite3Fts5ParseNodeFree(pRet);
+              pRet = 0;
+              pNear = 0;
+              assert( pLeft==0 && pRight==0 );
+            }
+          }
+        }else{
+          assert( pNear==0 );
+          fts5ExprAddChildren(pRet, pLeft);
+          fts5ExprAddChildren(pRet, pRight);
+          pLeft = pRight = 0;
+          if( pRet->iHeight>SQLITE_FTS5_MAX_EXPR_DEPTH ){
+            sqlite3Fts5ParseError(pParse,
+                "fts5 expression tree is too large (maximum depth %d)",
+                SQLITE_FTS5_MAX_EXPR_DEPTH
+            );
+            sqlite3Fts5ParseNodeFree(pRet);
+            pRet = 0;
+          }
+        }
+      }
+    }
+  }
+
+  if( pRet==0 ){
+    assert( pParse->rc!=SQLITE_OK );
+    sqlite3Fts5ParseNodeFree(pLeft);
+    sqlite3Fts5ParseNodeFree(pRight);
+    sqlite3Fts5ParseNearsetFree(pNear);
+  }
+  return pRet;
+}
+
+static Fts5ExprNode *sqlite3Fts5ParseImplicitAnd(
+  Fts5Parse *pParse,              /* Parse context */
+  Fts5ExprNode *pLeft,            /* Left hand child expression */
+  Fts5ExprNode *pRight            /* Right hand child expression */
+){
+  Fts5ExprNode *pRet = 0;
+  Fts5ExprNode *pPrev;
+
+  if( pParse->rc ){
+    sqlite3Fts5ParseNodeFree(pLeft);
+    sqlite3Fts5ParseNodeFree(pRight);
+  }else{
+
+    assert( pLeft->eType==FTS5_STRING
+        || pLeft->eType==FTS5_TERM
+        || pLeft->eType==FTS5_EOF
+        || pLeft->eType==FTS5_AND
+    );
+    assert( pRight->eType==FTS5_STRING
+        || pRight->eType==FTS5_TERM
+        || pRight->eType==FTS5_EOF
+        || (pRight->eType==FTS5_AND && pParse->bPhraseToAnd)
+    );
+
+    if( pLeft->eType==FTS5_AND ){
+      pPrev = pLeft->apChild[pLeft->nChild-1];
+    }else{
+      pPrev = pLeft;
+    }
+    assert( pPrev->eType==FTS5_STRING
+        || pPrev->eType==FTS5_TERM
+        || pPrev->eType==FTS5_EOF
+        );
+
+    if( pRight->eType==FTS5_EOF ){
+      assert( pParse->apPhrase!=0 );
+      assert( pParse->nPhrase>0 );
+      assert( pParse->apPhrase[pParse->nPhrase-1]==pRight->pNear->apPhrase[0] );
+      sqlite3Fts5ParseNodeFree(pRight);
+      pRet = pLeft;
+      pParse->nPhrase--;
+    }
+    else if( pPrev->eType==FTS5_EOF ){
+      Fts5ExprPhrase **ap;
+
+      if( pPrev==pLeft ){
+        pRet = pRight;
+      }else{
+        pLeft->apChild[pLeft->nChild-1] = pRight;
+        pRet = pLeft;
+      }
+
+      ap = &pParse->apPhrase[pParse->nPhrase-1-pRight->pNear->nPhrase];
+      assert( ap[0]==pPrev->pNear->apPhrase[0] );
+      memmove(ap, &ap[1], sizeof(Fts5ExprPhrase*)*pRight->pNear->nPhrase);
+      pParse->nPhrase--;
+
+      sqlite3Fts5ParseNodeFree(pPrev);
+    }
+    else{
+      pRet = sqlite3Fts5ParseNode(pParse, FTS5_AND, pLeft, pRight, 0);
+    }
+  }
+
+  return pRet;
+}
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+static char *fts5ExprTermPrint(Fts5ExprTerm *pTerm){
+  sqlite3_int64 nByte = 0;
+  Fts5ExprTerm *p;
+  char *zQuoted;
+
+  /* Determine the maximum amount of space required. */
+  for(p=pTerm; p; p=p->pSynonym){
+    nByte += pTerm->nQueryTerm * 2 + 3 + 2;
+  }
+  zQuoted = sqlite3_malloc64(nByte);
+
+  if( zQuoted ){
+    int i = 0;
+    for(p=pTerm; p; p=p->pSynonym){
+      char *zIn = p->pTerm;
+      char *zEnd = &zIn[p->nQueryTerm];
+      zQuoted[i++] = '"';
+      while( zIn<zEnd ){
+        if( *zIn=='"' ) zQuoted[i++] = '"';
+        zQuoted[i++] = *zIn++;
+      }
+      zQuoted[i++] = '"';
+      if( p->pSynonym ) zQuoted[i++] = '|';
+    }
+    if( pTerm->bPrefix ){
+      zQuoted[i++] = ' ';
+      zQuoted[i++] = '*';
+    }
+    zQuoted[i++] = '\0';
+  }
+  return zQuoted;
+}
+
+static char *fts5PrintfAppend(char *zApp, const char *zFmt, ...){
+  char *zNew;
+  va_list ap;
+  va_start(ap, zFmt);
+  zNew = sqlite3_vmprintf(zFmt, ap);
+  va_end(ap);
+  if( zApp && zNew ){
+    char *zNew2 = sqlite3_mprintf("%s%s", zApp, zNew);
+    sqlite3_free(zNew);
+    zNew = zNew2;
+  }
+  sqlite3_free(zApp);
+  return zNew;
+}
+
+/*
+** Compose a tcl-readable representation of expression pExpr. Return a
+** pointer to a buffer containing that representation. It is the
+** responsibility of the caller to at some point free the buffer using
+** sqlite3_free().
+*/
+static char *fts5ExprPrintTcl(
+  Fts5Config *pConfig,
+  const char *zNearsetCmd,
+  Fts5ExprNode *pExpr
+){
+  char *zRet = 0;
+  if( pExpr->eType==FTS5_STRING || pExpr->eType==FTS5_TERM ){
+    Fts5ExprNearset *pNear = pExpr->pNear;
+    int i;
+    int iTerm;
+
+    zRet = fts5PrintfAppend(zRet, "%s ", zNearsetCmd);
+    if( zRet==0 ) return 0;
+    if( pNear->pColset ){
+      int *aiCol = pNear->pColset->aiCol;
+      int nCol = pNear->pColset->nCol;
+      if( nCol==1 ){
+        zRet = fts5PrintfAppend(zRet, "-col %d ", aiCol[0]);
+      }else{
+        zRet = fts5PrintfAppend(zRet, "-col {%d", aiCol[0]);
+        for(i=1; i<pNear->pColset->nCol; i++){
+          zRet = fts5PrintfAppend(zRet, " %d", aiCol[i]);
+        }
+        zRet = fts5PrintfAppend(zRet, "} ");
+      }
+      if( zRet==0 ) return 0;
+    }
+
+    if( pNear->nPhrase>1 ){
+      zRet = fts5PrintfAppend(zRet, "-near %d ", pNear->nNear);
+      if( zRet==0 ) return 0;
+    }
+
+    zRet = fts5PrintfAppend(zRet, "--");
+    if( zRet==0 ) return 0;
+
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+
+      zRet = fts5PrintfAppend(zRet, " {");
+      for(iTerm=0; zRet && iTerm<pPhrase->nTerm; iTerm++){
+        Fts5ExprTerm *p = &pPhrase->aTerm[iTerm];
+        zRet = fts5PrintfAppend(zRet, "%s%.*s", iTerm==0?"":" ",
+            p->nQueryTerm, p->pTerm
+        );
+        if( pPhrase->aTerm[iTerm].bPrefix ){
+          zRet = fts5PrintfAppend(zRet, "*");
+        }
+      }
+
+      if( zRet ) zRet = fts5PrintfAppend(zRet, "}");
+      if( zRet==0 ) return 0;
+    }
+
+  }else if( pExpr->eType==0 ){
+    zRet = sqlite3_mprintf("{}");
+  }else{
+    char const *zOp = 0;
+    int i;
+    switch( pExpr->eType ){
+      case FTS5_AND: zOp = "AND"; break;
+      case FTS5_NOT: zOp = "NOT"; break;
+      default:
+        assert( pExpr->eType==FTS5_OR );
+        zOp = "OR";
+        break;
+    }
+
+    zRet = sqlite3_mprintf("%s", zOp);
+    for(i=0; zRet && i<pExpr->nChild; i++){
+      char *z = fts5ExprPrintTcl(pConfig, zNearsetCmd, pExpr->apChild[i]);
+      if( !z ){
+        sqlite3_free(zRet);
+        zRet = 0;
+      }else{
+        zRet = fts5PrintfAppend(zRet, " [%z]", z);
+      }
+    }
+  }
+
+  return zRet;
+}
+
+static char *fts5ExprPrint(Fts5Config *pConfig, Fts5ExprNode *pExpr){
+  char *zRet = 0;
+  if( pExpr->eType==0 ){
+    return sqlite3_mprintf("\"\"");
+  }else
+  if( pExpr->eType==FTS5_STRING || pExpr->eType==FTS5_TERM ){
+    Fts5ExprNearset *pNear = pExpr->pNear;
+    int i;
+    int iTerm;
+
+    if( pNear->pColset ){
+      int ii;
+      Fts5Colset *pColset = pNear->pColset;
+      if( pColset->nCol>1 ) zRet = fts5PrintfAppend(zRet, "{");
+      for(ii=0; ii<pColset->nCol; ii++){
+        zRet = fts5PrintfAppend(zRet, "%s%s",
+            pConfig->azCol[pColset->aiCol[ii]], ii==pColset->nCol-1 ? "" : " "
+        );
+      }
+      if( zRet ){
+        zRet = fts5PrintfAppend(zRet, "%s : ", pColset->nCol>1 ? "}" : "");
+      }
+      if( zRet==0 ) return 0;
+    }
+
+    if( pNear->nPhrase>1 ){
+      zRet = fts5PrintfAppend(zRet, "NEAR(");
+      if( zRet==0 ) return 0;
+    }
+
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      if( i!=0 ){
+        zRet = fts5PrintfAppend(zRet, " ");
+        if( zRet==0 ) return 0;
+      }
+      for(iTerm=0; iTerm<pPhrase->nTerm; iTerm++){
+        char *zTerm = fts5ExprTermPrint(&pPhrase->aTerm[iTerm]);
+        if( zTerm ){
+          zRet = fts5PrintfAppend(zRet, "%s%s", iTerm==0?"":" + ", zTerm);
+          sqlite3_free(zTerm);
+        }
+        if( zTerm==0 || zRet==0 ){
+          sqlite3_free(zRet);
+          return 0;
+        }
+      }
+    }
+
+    if( pNear->nPhrase>1 ){
+      zRet = fts5PrintfAppend(zRet, ", %d)", pNear->nNear);
+      if( zRet==0 ) return 0;
+    }
+
+  }else{
+    char const *zOp = 0;
+    int i;
+
+    switch( pExpr->eType ){
+      case FTS5_AND: zOp = " AND "; break;
+      case FTS5_NOT: zOp = " NOT "; break;
+      default:
+        assert( pExpr->eType==FTS5_OR );
+        zOp = " OR ";
+        break;
+    }
+
+    for(i=0; i<pExpr->nChild; i++){
+      char *z = fts5ExprPrint(pConfig, pExpr->apChild[i]);
+      if( z==0 ){
+        sqlite3_free(zRet);
+        zRet = 0;
+      }else{
+        int e = pExpr->apChild[i]->eType;
+        int b = (e!=FTS5_STRING && e!=FTS5_TERM && e!=FTS5_EOF);
+        zRet = fts5PrintfAppend(zRet, "%s%s%z%s",
+            (i==0 ? "" : zOp),
+            (b?"(":""), z, (b?")":"")
+        );
+      }
+      if( zRet==0 ) break;
+    }
+  }
+
+  return zRet;
+}
+
+/*
+** The implementation of user-defined scalar functions fts5_expr() (bTcl==0)
+** and fts5_expr_tcl() (bTcl!=0).
+*/
+static void fts5ExprFunction(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal,          /* Function arguments */
+  int bTcl
+){
+  Fts5Global *pGlobal = (Fts5Global*)sqlite3_user_data(pCtx);
+  sqlite3 *db = sqlite3_context_db_handle(pCtx);
+  const char *zExpr = 0;
+  char *zErr = 0;
+  Fts5Expr *pExpr = 0;
+  int rc;
+  int i;
+
+  const char **azConfig;          /* Array of arguments for Fts5Config */
+  const char *zNearsetCmd = "nearset";
+  int nConfig;                    /* Size of azConfig[] */
+  Fts5Config *pConfig = 0;
+  int iArg = 1;
+
+  if( nArg<1 ){
+    zErr = sqlite3_mprintf("wrong number of arguments to function %s",
+        bTcl ? "fts5_expr_tcl" : "fts5_expr"
+    );
+    sqlite3_result_error(pCtx, zErr, -1);
+    sqlite3_free(zErr);
+    return;
+  }
+
+  if( bTcl && nArg>1 ){
+    zNearsetCmd = (const char*)sqlite3_value_text(apVal[1]);
+    iArg = 2;
+  }
+
+  nConfig = 3 + (nArg-iArg);
+  azConfig = (const char**)sqlite3_malloc64(sizeof(char*) * nConfig);
+  if( azConfig==0 ){
+    sqlite3_result_error_nomem(pCtx);
+    return;
+  }
+  azConfig[0] = 0;
+  azConfig[1] = "main";
+  azConfig[2] = "tbl";
+  for(i=3; iArg<nArg; iArg++){
+    const char *z = (const char*)sqlite3_value_text(apVal[iArg]);
+    azConfig[i++] = (z ? z : "");
+  }
+
+  zExpr = (const char*)sqlite3_value_text(apVal[0]);
+  if( zExpr==0 ) zExpr = "";
+
+  rc = sqlite3Fts5ConfigParse(pGlobal, db, nConfig, azConfig, &pConfig, &zErr);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ExprNew(pConfig, 0, pConfig->nCol, zExpr, &pExpr, &zErr);
+  }
+  if( rc==SQLITE_OK ){
+    char *zText;
+    if( pExpr->pRoot->xNext==0 ){
+      zText = sqlite3_mprintf("");
+    }else if( bTcl ){
+      zText = fts5ExprPrintTcl(pConfig, zNearsetCmd, pExpr->pRoot);
+    }else{
+      zText = fts5ExprPrint(pConfig, pExpr->pRoot);
+    }
+    if( zText==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      sqlite3_result_text(pCtx, zText, -1, SQLITE_TRANSIENT);
+      sqlite3_free(zText);
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    if( zErr ){
+      sqlite3_result_error(pCtx, zErr, -1);
+      sqlite3_free(zErr);
+    }else{
+      sqlite3_result_error_code(pCtx, rc);
+    }
+  }
+  sqlite3_free((void *)azConfig);
+  sqlite3Fts5ConfigFree(pConfig);
+  sqlite3Fts5ExprFree(pExpr);
+}
+
+static void fts5ExprFunctionHr(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  fts5ExprFunction(pCtx, nArg, apVal, 0);
+}
+static void fts5ExprFunctionTcl(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  fts5ExprFunction(pCtx, nArg, apVal, 1);
+}
+
+/*
+** The implementation of an SQLite user-defined-function that accepts a
+** single integer as an argument. If the integer is an alpha-numeric
+** unicode code point, 1 is returned. Otherwise 0.
+*/
+static void fts5ExprIsAlnum(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  int iCode;
+  u8 aArr[32];
+  if( nArg!=1 ){
+    sqlite3_result_error(pCtx,
+        "wrong number of arguments to function fts5_isalnum", -1
+    );
+    return;
+  }
+  memset(aArr, 0, sizeof(aArr));
+  sqlite3Fts5UnicodeCatParse("L*", aArr);
+  sqlite3Fts5UnicodeCatParse("N*", aArr);
+  sqlite3Fts5UnicodeCatParse("Co", aArr);
+  iCode = sqlite3_value_int(apVal[0]);
+  sqlite3_result_int(pCtx, aArr[sqlite3Fts5UnicodeCategory((u32)iCode)]);
+}
+
+static void fts5ExprFold(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  if( nArg!=1 && nArg!=2 ){
+    sqlite3_result_error(pCtx,
+        "wrong number of arguments to function fts5_fold", -1
+    );
+  }else{
+    int iCode;
+    int bRemoveDiacritics = 0;
+    iCode = sqlite3_value_int(apVal[0]);
+    if( nArg==2 ) bRemoveDiacritics = sqlite3_value_int(apVal[1]);
+    sqlite3_result_int(pCtx, sqlite3Fts5UnicodeFold(iCode, bRemoveDiacritics));
+  }
+}
+#endif /* if SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+/*
+** This is called during initialization to register the fts5_expr() scalar
+** UDF with the SQLite handle passed as the only argument.
+*/
+static int sqlite3Fts5ExprInit(Fts5Global *pGlobal, sqlite3 *db){
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+  struct Fts5ExprFunc {
+    const char *z;
+    void (*x)(sqlite3_context*,int,sqlite3_value**);
+  } aFunc[] = {
+    { "fts5_expr",     fts5ExprFunctionHr },
+    { "fts5_expr_tcl", fts5ExprFunctionTcl },
+    { "fts5_isalnum",  fts5ExprIsAlnum },
+    { "fts5_fold",     fts5ExprFold },
+  };
+  int i;
+  int rc = SQLITE_OK;
+  void *pCtx = (void*)pGlobal;
+
+  for(i=0; rc==SQLITE_OK && i<ArraySize(aFunc); i++){
+    struct Fts5ExprFunc *p = &aFunc[i];
+    rc = sqlite3_create_function(db, p->z, -1, SQLITE_UTF8, pCtx, p->x, 0, 0);
+  }
+#else
+  int rc = SQLITE_OK;
+  UNUSED_PARAM2(pGlobal,db);
+#endif
+
+  /* Avoid warnings indicating that sqlite3Fts5ParserTrace() and
+  ** sqlite3Fts5ParserFallback() are unused */
+#ifndef NDEBUG
+  (void)sqlite3Fts5ParserTrace;
+#endif
+  (void)sqlite3Fts5ParserFallback;
+
+  return rc;
+}
+
+/*
+** Return the number of phrases in expression pExpr.
+*/
+static int sqlite3Fts5ExprPhraseCount(Fts5Expr *pExpr){
+  return (pExpr ? pExpr->nPhrase : 0);
+}
+
+/*
+** Return the number of terms in the iPhrase'th phrase in pExpr.
+*/
+static int sqlite3Fts5ExprPhraseSize(Fts5Expr *pExpr, int iPhrase){
+  if( iPhrase<0 || iPhrase>=pExpr->nPhrase ) return 0;
+  return pExpr->apExprPhrase[iPhrase]->nTerm;
+}
+
+/*
+** This function is used to access the current position list for phrase
+** iPhrase.
+*/
+static int sqlite3Fts5ExprPoslist(Fts5Expr *pExpr, int iPhrase, const u8 **pa){
+  int nRet;
+  Fts5ExprPhrase *pPhrase = pExpr->apExprPhrase[iPhrase];
+  Fts5ExprNode *pNode = pPhrase->pNode;
+  if( pNode->bEof==0 && pNode->iRowid==pExpr->pRoot->iRowid ){
+    *pa = pPhrase->poslist.p;
+    nRet = pPhrase->poslist.n;
+  }else{
+    *pa = 0;
+    nRet = 0;
+  }
+  return nRet;
+}
+
+struct Fts5PoslistPopulator {
+  Fts5PoslistWriter writer;
+  int bOk;                        /* True if ok to populate */
+  int bMiss;
+};
+
+/*
+** Clear the position lists associated with all phrases in the expression
+** passed as the first argument. Argument bLive is true if the expression
+** might be pointing to a real entry, otherwise it has just been reset.
+**
+** At present this function is only used for detail=col and detail=none
+** fts5 tables. This implies that all phrases must be at most 1 token
+** in size, as phrase matches are not supported without detail=full.
+*/
+static Fts5PoslistPopulator *sqlite3Fts5ExprClearPoslists(Fts5Expr *pExpr, int bLive){
+  Fts5PoslistPopulator *pRet;
+  pRet = sqlite3_malloc64(sizeof(Fts5PoslistPopulator)*pExpr->nPhrase);
+  if( pRet ){
+    int i;
+    memset(pRet, 0, sizeof(Fts5PoslistPopulator)*pExpr->nPhrase);
+    for(i=0; i<pExpr->nPhrase; i++){
+      Fts5Buffer *pBuf = &pExpr->apExprPhrase[i]->poslist;
+      Fts5ExprNode *pNode = pExpr->apExprPhrase[i]->pNode;
+      assert( pExpr->apExprPhrase[i]->nTerm<=1 );
+      if( bLive &&
+          (pBuf->n==0 || pNode->iRowid!=pExpr->pRoot->iRowid || pNode->bEof)
+      ){
+        pRet[i].bMiss = 1;
+      }else{
+        pBuf->n = 0;
+      }
+    }
+  }
+  return pRet;
+}
+
+struct Fts5ExprCtx {
+  Fts5Expr *pExpr;
+  Fts5PoslistPopulator *aPopulator;
+  i64 iOff;
+};
+typedef struct Fts5ExprCtx Fts5ExprCtx;
+
+/*
+** TODO: Make this more efficient!
+*/
+static int fts5ExprColsetTest(Fts5Colset *pColset, int iCol){
+  int i;
+  for(i=0; i<pColset->nCol; i++){
+    if( pColset->aiCol[i]==iCol ) return 1;
+  }
+  return 0;
+}
+
+/*
+** pToken is a buffer nToken bytes in size that may or may not contain
+** an embedded 0x00 byte. If it does, return the number of bytes in
+** the buffer before the 0x00. If it does not, return nToken.
+*/
+static int fts5QueryTerm(const char *pToken, int nToken){
+  int ii;
+  for(ii=0; ii<nToken && pToken[ii]; ii++){}
+  return ii;
+}
+
+static int fts5ExprPopulatePoslistsCb(
+  void *pCtx,                /* Copy of 2nd argument to xTokenize() */
+  int tflags,                /* Mask of FTS5_TOKEN_* flags */
+  const char *pToken,        /* Pointer to buffer containing token */
+  int nToken,                /* Size of token in bytes */
+  int iUnused1,              /* Byte offset of token within input text */
+  int iUnused2               /* Byte offset of end of token within input text */
+){
+  Fts5ExprCtx *p = (Fts5ExprCtx*)pCtx;
+  Fts5Expr *pExpr = p->pExpr;
+  int i;
+  int nQuery = nToken;
+  i64 iRowid = pExpr->pRoot->iRowid;
+
+  UNUSED_PARAM2(iUnused1, iUnused2);
+
+  if( nQuery>FTS5_MAX_TOKEN_SIZE ) nQuery = FTS5_MAX_TOKEN_SIZE;
+  if( pExpr->pConfig->bTokendata ){
+    nQuery = fts5QueryTerm(pToken, nQuery);
+  }
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 ) p->iOff++;
+  for(i=0; i<pExpr->nPhrase; i++){
+    Fts5ExprTerm *pT;
+    if( p->aPopulator[i].bOk==0 ) continue;
+    for(pT=&pExpr->apExprPhrase[i]->aTerm[0]; pT; pT=pT->pSynonym){
+      if( (pT->nQueryTerm==nQuery || (pT->nQueryTerm<nQuery && pT->bPrefix))
+       && memcmp(pT->pTerm, pToken, pT->nQueryTerm)==0
+      ){
+        int rc = sqlite3Fts5PoslistWriterAppend(
+            &pExpr->apExprPhrase[i]->poslist, &p->aPopulator[i].writer, p->iOff
+        );
+        if( rc==SQLITE_OK && (pExpr->pConfig->bTokendata || pT->bPrefix) ){
+          int iCol = p->iOff>>32;
+          int iTokOff = p->iOff & 0x7FFFFFFF;
+          rc = sqlite3Fts5IndexIterWriteTokendata(
+              pT->pIter, pToken, nToken, iRowid, iCol, iTokOff
+          );
+        }
+        if( rc ) return rc;
+        break;
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+static int sqlite3Fts5ExprPopulatePoslists(
+  Fts5Config *pConfig,
+  Fts5Expr *pExpr,
+  Fts5PoslistPopulator *aPopulator,
+  int iCol,
+  const char *z, int n
+){
+  int i;
+  Fts5ExprCtx sCtx;
+  sCtx.pExpr = pExpr;
+  sCtx.aPopulator = aPopulator;
+  sCtx.iOff = (((i64)iCol) << 32) - 1;
+
+  for(i=0; i<pExpr->nPhrase; i++){
+    Fts5ExprNode *pNode = pExpr->apExprPhrase[i]->pNode;
+    Fts5Colset *pColset = pNode->pNear->pColset;
+    if( (pColset && 0==fts5ExprColsetTest(pColset, iCol))
+     || aPopulator[i].bMiss
+    ){
+      aPopulator[i].bOk = 0;
+    }else{
+      aPopulator[i].bOk = 1;
+    }
+  }
+
+  return sqlite3Fts5Tokenize(pConfig,
+      FTS5_TOKENIZE_DOCUMENT, z, n, (void*)&sCtx, fts5ExprPopulatePoslistsCb
+  );
+}
+
+static void fts5ExprClearPoslists(Fts5ExprNode *pNode){
+  if( pNode->eType==FTS5_TERM || pNode->eType==FTS5_STRING ){
+    pNode->pNear->apPhrase[0]->poslist.n = 0;
+  }else{
+    int i;
+    for(i=0; i<pNode->nChild; i++){
+      fts5ExprClearPoslists(pNode->apChild[i]);
+    }
+  }
+}
+
+static int fts5ExprCheckPoslists(Fts5ExprNode *pNode, i64 iRowid){
+  pNode->iRowid = iRowid;
+  pNode->bEof = 0;
+  switch( pNode->eType ){
+    case 0:
+    case FTS5_TERM:
+    case FTS5_STRING:
+      return (pNode->pNear->apPhrase[0]->poslist.n>0);
+
+    case FTS5_AND: {
+      int i;
+      for(i=0; i<pNode->nChild; i++){
+        if( fts5ExprCheckPoslists(pNode->apChild[i], iRowid)==0 ){
+          fts5ExprClearPoslists(pNode);
+          return 0;
+        }
+      }
+      break;
+    }
+
+    case FTS5_OR: {
+      int i;
+      int bRet = 0;
+      for(i=0; i<pNode->nChild; i++){
+        if( fts5ExprCheckPoslists(pNode->apChild[i], iRowid) ){
+          bRet = 1;
+        }
+      }
+      return bRet;
+    }
+
+    default: {
+      assert( pNode->eType==FTS5_NOT );
+      if( 0==fts5ExprCheckPoslists(pNode->apChild[0], iRowid)
+          || 0!=fts5ExprCheckPoslists(pNode->apChild[1], iRowid)
+        ){
+        fts5ExprClearPoslists(pNode);
+        return 0;
+      }
+      break;
+    }
+  }
+  return 1;
+}
+
+static void sqlite3Fts5ExprCheckPoslists(Fts5Expr *pExpr, i64 iRowid){
+  fts5ExprCheckPoslists(pExpr->pRoot, iRowid);
+}
+
+/*
+** This function is only called for detail=columns tables.
+*/
+static int sqlite3Fts5ExprPhraseCollist(
+  Fts5Expr *pExpr,
+  int iPhrase,
+  const u8 **ppCollist,
+  int *pnCollist
+){
+  Fts5ExprPhrase *pPhrase = pExpr->apExprPhrase[iPhrase];
+  Fts5ExprNode *pNode = pPhrase->pNode;
+  int rc = SQLITE_OK;
+
+  assert( iPhrase>=0 && iPhrase<pExpr->nPhrase );
+  assert( pExpr->pConfig->eDetail==FTS5_DETAIL_COLUMNS );
+
+  if( pNode->bEof==0
+   && pNode->iRowid==pExpr->pRoot->iRowid
+   && pPhrase->poslist.n>0
+  ){
+    Fts5ExprTerm *pTerm = &pPhrase->aTerm[0];
+    if( pTerm->pSynonym ){
+      Fts5Buffer *pBuf = (Fts5Buffer*)&pTerm->pSynonym[1];
+      rc = fts5ExprSynonymList(
+          pTerm, pNode->iRowid, pBuf, (u8**)ppCollist, pnCollist
+      );
+    }else{
+      *ppCollist = pPhrase->aTerm[0].pIter->pData;
+      *pnCollist = pPhrase->aTerm[0].pIter->nData;
+    }
+  }else{
+    *ppCollist = 0;
+    *pnCollist = 0;
+  }
+
+  return rc;
+}
+
+/*
+** Does the work of the fts5_api.xQueryToken() API method.
+*/
+static int sqlite3Fts5ExprQueryToken(
+  Fts5Expr *pExpr,
+  int iPhrase,
+  int iToken,
+  const char **ppOut,
+  int *pnOut
+){
+  Fts5ExprPhrase *pPhrase = 0;
+
+  if( iPhrase<0 || iPhrase>=pExpr->nPhrase ){
+    return SQLITE_RANGE;
+  }
+  pPhrase = pExpr->apExprPhrase[iPhrase];
+  if( iToken<0 || iToken>=pPhrase->nTerm ){
+    return SQLITE_RANGE;
+  }
+
+  *ppOut = pPhrase->aTerm[iToken].pTerm;
+  *pnOut = pPhrase->aTerm[iToken].nFullTerm;
+  return SQLITE_OK;
+}
+
+/*
+** Does the work of the fts5_api.xInstToken() API method.
+*/
+static int sqlite3Fts5ExprInstToken(
+  Fts5Expr *pExpr,
+  i64 iRowid,
+  int iPhrase,
+  int iCol,
+  int iOff,
+  int iToken,
+  const char **ppOut,
+  int *pnOut
+){
+  Fts5ExprPhrase *pPhrase = 0;
+  Fts5ExprTerm *pTerm = 0;
+  int rc = SQLITE_OK;
+
+  if( iPhrase<0 || iPhrase>=pExpr->nPhrase ){
+    return SQLITE_RANGE;
+  }
+  pPhrase = pExpr->apExprPhrase[iPhrase];
+  if( iToken<0 || iToken>=pPhrase->nTerm ){
+    return SQLITE_RANGE;
+  }
+  pTerm = &pPhrase->aTerm[iToken];
+  if( pExpr->pConfig->bTokendata || pTerm->bPrefix ){
+    rc = sqlite3Fts5IterToken(
+        pTerm->pIter, pTerm->pTerm, pTerm->nQueryTerm,
+        iRowid, iCol, iOff+iToken, ppOut, pnOut
+    );
+  }else{
+    *ppOut = pTerm->pTerm;
+    *pnOut = pTerm->nFullTerm;
+  }
+  return rc;
+}
+
+/*
+** Clear the token mappings for all Fts5IndexIter objects mannaged by
+** the expression passed as the only argument.
+*/
+static void sqlite3Fts5ExprClearTokens(Fts5Expr *pExpr){
+  int ii;
+  for(ii=0; ii<pExpr->nPhrase; ii++){
+    Fts5ExprTerm *pT;
+    for(pT=&pExpr->apExprPhrase[ii]->aTerm[0]; pT; pT=pT->pSynonym){
+      sqlite3Fts5IndexIterClearTokendata(pT->pIter);
+    }
+  }
+}
+
+/*
+** 2014 August 11
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+
+
+
+/* #include "fts5Int.h" */
+
+typedef struct Fts5HashEntry Fts5HashEntry;
+
+/*
+** This file contains the implementation of an in-memory hash table used
+** to accumuluate "term -> doclist" content before it is flused to a level-0
+** segment.
+*/
+
+
+struct Fts5Hash {
+  int eDetail;                    /* Copy of Fts5Config.eDetail */
+  int *pnByte;                    /* Pointer to bytes counter */
+  int nEntry;                     /* Number of entries currently in hash */
+  int nSlot;                      /* Size of aSlot[] array */
+  Fts5HashEntry *pScan;           /* Current ordered scan item */
+  Fts5HashEntry **aSlot;          /* Array of hash slots */
+};
+
+/*
+** Each entry in the hash table is represented by an object of the
+** following type. Each object, its key, and its current data are stored
+** in a single memory allocation. The key immediately follows the object
+** in memory. The position list data immediately follows the key data
+** in memory.
+**
+** The key is Fts5HashEntry.nKey bytes in size. It consists of a single
+** byte identifying the index (either the main term index or a prefix-index),
+** followed by the term data. For example: "0token". There is no
+** nul-terminator - in this case nKey=6.
+**
+** The data that follows the key is in a similar, but not identical format
+** to the doclist data stored in the database. It is:
+**
+**   * Rowid, as a varint
+**   * Position list, without 0x00 terminator.
+**   * Size of previous position list and rowid, as a 4 byte
+**     big-endian integer.
+**
+** iRowidOff:
+**   Offset of last rowid written to data area. Relative to first byte of
+**   structure.
+**
+** nData:
+**   Bytes of data written since iRowidOff.
+*/
+struct Fts5HashEntry {
+  Fts5HashEntry *pHashNext;       /* Next hash entry with same hash-key */
+  Fts5HashEntry *pScanNext;       /* Next entry in sorted order */
+
+  int nAlloc;                     /* Total size of allocation */
+  int iSzPoslist;                 /* Offset of space for 4-byte poslist size */
+  int nData;                      /* Total bytes of data (incl. structure) */
+  int nKey;                       /* Length of key in bytes */
+  u8 bDel;                        /* Set delete-flag @ iSzPoslist */
+  u8 bContent;                    /* Set content-flag (detail=none mode) */
+  i16 iCol;                       /* Column of last value written */
+  int iPos;                       /* Position of last value written */
+  i64 iRowid;                     /* Rowid of last value written */
+};
+
+/*
+** Eqivalent to:
+**
+**   char *fts5EntryKey(Fts5HashEntry *pEntry){ return zKey; }
+*/
+#define fts5EntryKey(p) ( ((char *)(&(p)[1])) )
+
+
+/*
+** Allocate a new hash table.
+*/
+static int sqlite3Fts5HashNew(Fts5Config *pConfig, Fts5Hash **ppNew, int *pnByte){
+  int rc = SQLITE_OK;
+  Fts5Hash *pNew;
+
+  *ppNew = pNew = (Fts5Hash*)sqlite3_malloc(sizeof(Fts5Hash));
+  if( pNew==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_int64 nByte;
+    memset(pNew, 0, sizeof(Fts5Hash));
+    pNew->pnByte = pnByte;
+    pNew->eDetail = pConfig->eDetail;
+
+    pNew->nSlot = 1024;
+    nByte = sizeof(Fts5HashEntry*) * pNew->nSlot;
+    pNew->aSlot = (Fts5HashEntry**)sqlite3_malloc64(nByte);
+    if( pNew->aSlot==0 ){
+      sqlite3_free(pNew);
+      *ppNew = 0;
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pNew->aSlot, 0, (size_t)nByte);
+    }
+  }
+  return rc;
+}
+
+/*
+** Free a hash table object.
+*/
+static void sqlite3Fts5HashFree(Fts5Hash *pHash){
+  if( pHash ){
+    sqlite3Fts5HashClear(pHash);
+    sqlite3_free(pHash->aSlot);
+    sqlite3_free(pHash);
+  }
+}
+
+/*
+** Empty (but do not delete) a hash table.
+*/
+static void sqlite3Fts5HashClear(Fts5Hash *pHash){
+  int i;
+  for(i=0; i<pHash->nSlot; i++){
+    Fts5HashEntry *pNext;
+    Fts5HashEntry *pSlot;
+    for(pSlot=pHash->aSlot[i]; pSlot; pSlot=pNext){
+      pNext = pSlot->pHashNext;
+      sqlite3_free(pSlot);
+    }
+  }
+  memset(pHash->aSlot, 0, pHash->nSlot * sizeof(Fts5HashEntry*));
+  pHash->nEntry = 0;
+}
+
+static unsigned int fts5HashKey(int nSlot, const u8 *p, int n){
+  int i;
+  unsigned int h = 13;
+  for(i=n-1; i>=0; i--){
+    h = (h << 3) ^ h ^ p[i];
+  }
+  return (h % nSlot);
+}
+
+static unsigned int fts5HashKey2(int nSlot, u8 b, const u8 *p, int n){
+  int i;
+  unsigned int h = 13;
+  for(i=n-1; i>=0; i--){
+    h = (h << 3) ^ h ^ p[i];
+  }
+  h = (h << 3) ^ h ^ b;
+  return (h % nSlot);
+}
+
+/*
+** Resize the hash table by doubling the number of slots.
+*/
+static int fts5HashResize(Fts5Hash *pHash){
+  int nNew = pHash->nSlot*2;
+  int i;
+  Fts5HashEntry **apNew;
+  Fts5HashEntry **apOld = pHash->aSlot;
+
+  apNew = (Fts5HashEntry**)sqlite3_malloc64(nNew*sizeof(Fts5HashEntry*));
+  if( !apNew ) return SQLITE_NOMEM;
+  memset(apNew, 0, nNew*sizeof(Fts5HashEntry*));
+
+  for(i=0; i<pHash->nSlot; i++){
+    while( apOld[i] ){
+      unsigned int iHash;
+      Fts5HashEntry *p = apOld[i];
+      apOld[i] = p->pHashNext;
+      iHash = fts5HashKey(nNew, (u8*)fts5EntryKey(p), p->nKey);
+      p->pHashNext = apNew[iHash];
+      apNew[iHash] = p;
+    }
+  }
+
+  sqlite3_free(apOld);
+  pHash->nSlot = nNew;
+  pHash->aSlot = apNew;
+  return SQLITE_OK;
+}
+
+static int fts5HashAddPoslistSize(
+  Fts5Hash *pHash,
+  Fts5HashEntry *p,
+  Fts5HashEntry *p2
+){
+  int nRet = 0;
+  if( p->iSzPoslist ){
+    u8 *pPtr = p2 ? (u8*)p2 : (u8*)p;
+    int nData = p->nData;
+    if( pHash->eDetail==FTS5_DETAIL_NONE ){
+      assert( nData==p->iSzPoslist );
+      if( p->bDel ){
+        pPtr[nData++] = 0x00;
+        if( p->bContent ){
+          pPtr[nData++] = 0x00;
+        }
+      }
+    }else{
+      int nSz = (nData - p->iSzPoslist - 1);       /* Size in bytes */
+      int nPos = nSz*2 + p->bDel;                     /* Value of nPos field */
+
+      assert( p->bDel==0 || p->bDel==1 );
+      if( nPos<=127 ){
+        pPtr[p->iSzPoslist] = (u8)nPos;
+      }else{
+        int nByte = sqlite3Fts5GetVarintLen((u32)nPos);
+        memmove(&pPtr[p->iSzPoslist + nByte], &pPtr[p->iSzPoslist + 1], nSz);
+        sqlite3Fts5PutVarint(&pPtr[p->iSzPoslist], nPos);
+        nData += (nByte-1);
+      }
+    }
+
+    nRet = nData - p->nData;
+    if( p2==0 ){
+      p->iSzPoslist = 0;
+      p->bDel = 0;
+      p->bContent = 0;
+      p->nData = nData;
+    }
+  }
+  return nRet;
+}
+
+/*
+** Add an entry to the in-memory hash table. The key is the concatenation
+** of bByte and (pToken/nToken). The value is (iRowid/iCol/iPos).
+**
+**     (bByte || pToken) -> (iRowid,iCol,iPos)
+**
+** Or, if iCol is negative, then the value is a delete marker.
+*/
+static int sqlite3Fts5HashWrite(
+  Fts5Hash *pHash,
+  i64 iRowid,                     /* Rowid for this entry */
+  int iCol,                       /* Column token appears in (-ve -> delete) */
+  int iPos,                       /* Position of token within column */
+  char bByte,                     /* First byte of token */
+  const char *pToken, int nToken  /* Token to add or remove to or from index */
+){
+  unsigned int iHash;
+  Fts5HashEntry *p;
+  u8 *pPtr;
+  int nIncr = 0;                  /* Amount to increment (*pHash->pnByte) by */
+  int bNew;                       /* If non-delete entry should be written */
+
+  bNew = (pHash->eDetail==FTS5_DETAIL_FULL);
+
+  /* Attempt to locate an existing hash entry */
+  iHash = fts5HashKey2(pHash->nSlot, (u8)bByte, (const u8*)pToken, nToken);
+  for(p=pHash->aSlot[iHash]; p; p=p->pHashNext){
+    char *zKey = fts5EntryKey(p);
+    if( zKey[0]==bByte
+     && p->nKey==nToken+1
+     && memcmp(&zKey[1], pToken, nToken)==0
+    ){
+      break;
+    }
+  }
+
+  /* If an existing hash entry cannot be found, create a new one. */
+  if( p==0 ){
+    /* Figure out how much space to allocate */
+    char *zKey;
+    sqlite3_int64 nByte = sizeof(Fts5HashEntry) + (nToken+1) + 1 + 64;
+    if( nByte<128 ) nByte = 128;
+
+    /* Grow the Fts5Hash.aSlot[] array if necessary. */
+    if( (pHash->nEntry*2)>=pHash->nSlot ){
+      int rc = fts5HashResize(pHash);
+      if( rc!=SQLITE_OK ) return rc;
+      iHash = fts5HashKey2(pHash->nSlot, (u8)bByte, (const u8*)pToken, nToken);
+    }
+
+    /* Allocate new Fts5HashEntry and add it to the hash table. */
+    p = (Fts5HashEntry*)sqlite3_malloc64(nByte);
+    if( !p ) return SQLITE_NOMEM;
+    memset(p, 0, sizeof(Fts5HashEntry));
+    p->nAlloc = (int)nByte;
+    zKey = fts5EntryKey(p);
+    zKey[0] = bByte;
+    memcpy(&zKey[1], pToken, nToken);
+    assert( iHash==fts5HashKey(pHash->nSlot, (u8*)zKey, nToken+1) );
+    p->nKey = nToken+1;
+    zKey[nToken+1] = '\0';
+    p->nData = nToken+1 + sizeof(Fts5HashEntry);
+    p->pHashNext = pHash->aSlot[iHash];
+    pHash->aSlot[iHash] = p;
+    pHash->nEntry++;
+
+    /* Add the first rowid field to the hash-entry */
+    p->nData += sqlite3Fts5PutVarint(&((u8*)p)[p->nData], iRowid);
+    p->iRowid = iRowid;
+
+    p->iSzPoslist = p->nData;
+    if( pHash->eDetail!=FTS5_DETAIL_NONE ){
+      p->nData += 1;
+      p->iCol = (pHash->eDetail==FTS5_DETAIL_FULL ? 0 : -1);
+    }
+
+  }else{
+
+    /* Appending to an existing hash-entry. Check that there is enough
+    ** space to append the largest possible new entry. Worst case scenario
+    ** is:
+    **
+    **     + 9 bytes for a new rowid,
+    **     + 4 byte reserved for the "poslist size" varint.
+    **     + 1 byte for a "new column" byte,
+    **     + 3 bytes for a new column number (16-bit max) as a varint,
+    **     + 5 bytes for the new position offset (32-bit max).
+    */
+    if( (p->nAlloc - p->nData) < (9 + 4 + 1 + 3 + 5) ){
+      sqlite3_int64 nNew = p->nAlloc * 2;
+      Fts5HashEntry *pNew;
+      Fts5HashEntry **pp;
+      pNew = (Fts5HashEntry*)sqlite3_realloc64(p, nNew);
+      if( pNew==0 ) return SQLITE_NOMEM;
+      pNew->nAlloc = (int)nNew;
+      for(pp=&pHash->aSlot[iHash]; *pp!=p; pp=&(*pp)->pHashNext);
+      *pp = pNew;
+      p = pNew;
+    }
+    nIncr -= p->nData;
+  }
+  assert( (p->nAlloc - p->nData) >= (9 + 4 + 1 + 3 + 5) );
+
+  pPtr = (u8*)p;
+
+  /* If this is a new rowid, append the 4-byte size field for the previous
+  ** entry, and the new rowid for this entry.  */
+  if( iRowid!=p->iRowid ){
+    u64 iDiff = (u64)iRowid - (u64)p->iRowid;
+    fts5HashAddPoslistSize(pHash, p, 0);
+    p->nData += sqlite3Fts5PutVarint(&pPtr[p->nData], iDiff);
+    p->iRowid = iRowid;
+    bNew = 1;
+    p->iSzPoslist = p->nData;
+    if( pHash->eDetail!=FTS5_DETAIL_NONE ){
+      p->nData += 1;
+      p->iCol = (pHash->eDetail==FTS5_DETAIL_FULL ? 0 : -1);
+      p->iPos = 0;
+    }
+  }
+
+  if( iCol>=0 ){
+    if( pHash->eDetail==FTS5_DETAIL_NONE ){
+      p->bContent = 1;
+    }else{
+      /* Append a new column value, if necessary */
+      assert_nc( iCol>=p->iCol );
+      if( iCol!=p->iCol ){
+        if( pHash->eDetail==FTS5_DETAIL_FULL ){
+          pPtr[p->nData++] = 0x01;
+          p->nData += sqlite3Fts5PutVarint(&pPtr[p->nData], iCol);
+          p->iCol = (i16)iCol;
+          p->iPos = 0;
+        }else{
+          bNew = 1;
+          p->iCol = (i16)(iPos = iCol);
+        }
+      }
+
+      /* Append the new position offset, if necessary */
+      if( bNew ){
+        p->nData += sqlite3Fts5PutVarint(&pPtr[p->nData], iPos - p->iPos + 2);
+        p->iPos = iPos;
+      }
+    }
+  }else{
+    /* This is a delete. Set the delete flag. */
+    p->bDel = 1;
+  }
+
+  nIncr += p->nData;
+  *pHash->pnByte += nIncr;
+  return SQLITE_OK;
+}
+
+
+/*
+** Arguments pLeft and pRight point to linked-lists of hash-entry objects,
+** each sorted in key order. This function merges the two lists into a
+** single list and returns a pointer to its first element.
+*/
+static Fts5HashEntry *fts5HashEntryMerge(
+  Fts5HashEntry *pLeft,
+  Fts5HashEntry *pRight
+){
+  Fts5HashEntry *p1 = pLeft;
+  Fts5HashEntry *p2 = pRight;
+  Fts5HashEntry *pRet = 0;
+  Fts5HashEntry **ppOut = &pRet;
+
+  while( p1 || p2 ){
+    if( p1==0 ){
+      *ppOut = p2;
+      p2 = 0;
+    }else if( p2==0 ){
+      *ppOut = p1;
+      p1 = 0;
+    }else{
+      char *zKey1 = fts5EntryKey(p1);
+      char *zKey2 = fts5EntryKey(p2);
+      int nMin = MIN(p1->nKey, p2->nKey);
+
+      int cmp = memcmp(zKey1, zKey2, nMin);
+      if( cmp==0 ){
+        cmp = p1->nKey - p2->nKey;
+      }
+      assert( cmp!=0 );
+
+      if( cmp>0 ){
+        /* p2 is smaller */
+        *ppOut = p2;
+        ppOut = &p2->pScanNext;
+        p2 = p2->pScanNext;
+      }else{
+        /* p1 is smaller */
+        *ppOut = p1;
+        ppOut = &p1->pScanNext;
+        p1 = p1->pScanNext;
+      }
+      *ppOut = 0;
+    }
+  }
+
+  return pRet;
+}
+
+/*
+** Link all tokens from hash table iHash into a list in sorted order. The
+** tokens are not removed from the hash table.
+*/
+static int fts5HashEntrySort(
+  Fts5Hash *pHash,
+  const char *pTerm, int nTerm,   /* Query prefix, if any */
+  Fts5HashEntry **ppSorted
+){
+  const int nMergeSlot = 32;
+  Fts5HashEntry **ap;
+  Fts5HashEntry *pList;
+  int iSlot;
+  int i;
+
+  *ppSorted = 0;
+  ap = sqlite3_malloc64(sizeof(Fts5HashEntry*) * nMergeSlot);
+  if( !ap ) return SQLITE_NOMEM;
+  memset(ap, 0, sizeof(Fts5HashEntry*) * nMergeSlot);
+
+  for(iSlot=0; iSlot<pHash->nSlot; iSlot++){
+    Fts5HashEntry *pIter;
+    for(pIter=pHash->aSlot[iSlot]; pIter; pIter=pIter->pHashNext){
+      if( pTerm==0
+       || (pIter->nKey>=nTerm && 0==memcmp(fts5EntryKey(pIter), pTerm, nTerm))
+      ){
+        Fts5HashEntry *pEntry = pIter;
+        pEntry->pScanNext = 0;
+        for(i=0; ap[i]; i++){
+          pEntry = fts5HashEntryMerge(pEntry, ap[i]);
+          ap[i] = 0;
+        }
+        ap[i] = pEntry;
+      }
+    }
+  }
+
+  pList = 0;
+  for(i=0; i<nMergeSlot; i++){
+    pList = fts5HashEntryMerge(pList, ap[i]);
+  }
+
+  sqlite3_free(ap);
+  *ppSorted = pList;
+  return SQLITE_OK;
+}
+
+/*
+** Query the hash table for a doclist associated with term pTerm/nTerm.
+*/
+static int sqlite3Fts5HashQuery(
+  Fts5Hash *pHash,                /* Hash table to query */
+  int nPre,
+  const char *pTerm, int nTerm,   /* Query term */
+  void **ppOut,                   /* OUT: Pointer to new object */
+  int *pnDoclist                  /* OUT: Size of doclist in bytes */
+){
+  unsigned int iHash = fts5HashKey(pHash->nSlot, (const u8*)pTerm, nTerm);
+  char *zKey = 0;
+  Fts5HashEntry *p;
+
+  for(p=pHash->aSlot[iHash]; p; p=p->pHashNext){
+    zKey = fts5EntryKey(p);
+    if( nTerm==p->nKey && memcmp(zKey, pTerm, nTerm)==0 ) break;
+  }
+
+  if( p ){
+    int nHashPre = sizeof(Fts5HashEntry) + nTerm;
+    int nList = p->nData - nHashPre;
+    u8 *pRet = (u8*)(*ppOut = sqlite3_malloc64(nPre + nList + 10));
+    if( pRet ){
+      Fts5HashEntry *pFaux = (Fts5HashEntry*)&pRet[nPre-nHashPre];
+      memcpy(&pRet[nPre], &((u8*)p)[nHashPre], nList);
+      nList += fts5HashAddPoslistSize(pHash, p, pFaux);
+      *pnDoclist = nList;
+    }else{
+      *pnDoclist = 0;
+      return SQLITE_NOMEM;
+    }
+  }else{
+    *ppOut = 0;
+    *pnDoclist = 0;
+  }
+
+  return SQLITE_OK;
+}
+
+static int sqlite3Fts5HashScanInit(
+  Fts5Hash *p,                    /* Hash table to query */
+  const char *pTerm, int nTerm    /* Query prefix */
+){
+  return fts5HashEntrySort(p, pTerm, nTerm, &p->pScan);
+}
+
+#ifdef SQLITE_DEBUG
+static int fts5HashCount(Fts5Hash *pHash){
+  int nEntry = 0;
+  int ii;
+  for(ii=0; ii<pHash->nSlot; ii++){
+    Fts5HashEntry *p = 0;
+    for(p=pHash->aSlot[ii]; p; p=p->pHashNext){
+      nEntry++;
+    }
+  }
+  return nEntry;
+}
+#endif
+
+/*
+** Return true if the hash table is empty, false otherwise.
+*/
+static int sqlite3Fts5HashIsEmpty(Fts5Hash *pHash){
+  assert( pHash->nEntry==fts5HashCount(pHash) );
+  return pHash->nEntry==0;
+}
+
+static void sqlite3Fts5HashScanNext(Fts5Hash *p){
+  assert( !sqlite3Fts5HashScanEof(p) );
+  p->pScan = p->pScan->pScanNext;
+}
+
+static int sqlite3Fts5HashScanEof(Fts5Hash *p){
+  return (p->pScan==0);
+}
+
+static void sqlite3Fts5HashScanEntry(
+  Fts5Hash *pHash,
+  const char **pzTerm,            /* OUT: term (nul-terminated) */
+  int *pnTerm,                    /* OUT: Size of term in bytes */
+  const u8 **ppDoclist,           /* OUT: pointer to doclist */
+  int *pnDoclist                  /* OUT: size of doclist in bytes */
+){
+  Fts5HashEntry *p;
+  if( (p = pHash->pScan) ){
+    char *zKey = fts5EntryKey(p);
+    int nTerm = p->nKey;
+    fts5HashAddPoslistSize(pHash, p, 0);
+    *pzTerm = zKey;
+    *pnTerm = nTerm;
+    *ppDoclist = (const u8*)&zKey[nTerm];
+    *pnDoclist = p->nData - (sizeof(Fts5HashEntry) + nTerm);
+  }else{
+    *pzTerm = 0;
+    *pnTerm = 0;
+    *ppDoclist = 0;
+    *pnDoclist = 0;
+  }
+}
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Low level access to the FTS index stored in the database file. The
+** routines in this file file implement all read and write access to the
+** %_data table. Other parts of the system access this functionality via
+** the interface defined in fts5Int.h.
+*/
+
+
+/* #include "fts5Int.h" */
+
+/*
+** Overview:
+**
+** The %_data table contains all the FTS indexes for an FTS5 virtual table.
+** As well as the main term index, there may be up to 31 prefix indexes.
+** The format is similar to FTS3/4, except that:
+**
+**   * all segment b-tree leaf data is stored in fixed size page records
+**     (e.g. 1000 bytes). A single doclist may span multiple pages. Care is
+**     taken to ensure it is possible to iterate in either direction through
+**     the entries in a doclist, or to seek to a specific entry within a
+**     doclist, without loading it into memory.
+**
+**   * large doclists that span many pages have associated "doclist index"
+**     records that contain a copy of the first rowid on each page spanned by
+**     the doclist. This is used to speed up seek operations, and merges of
+**     large doclists with very small doclists.
+**
+**   * extra fields in the "structure record" record the state of ongoing
+**     incremental merge operations.
+**
+*/
+
+
+#define FTS5_OPT_WORK_UNIT  1000  /* Number of leaf pages per optimize step */
+#define FTS5_WORK_UNIT      64    /* Number of leaf pages in unit of work */
+
+#define FTS5_MIN_DLIDX_SIZE 4     /* Add dlidx if this many empty pages */
+
+#define FTS5_MAIN_PREFIX '0'
+
+#if FTS5_MAX_PREFIX_INDEXES > 31
+# error "FTS5_MAX_PREFIX_INDEXES is too large"
+#endif
+
+#define FTS5_MAX_LEVEL 64
+
+/*
+** There are two versions of the format used for the structure record:
+**
+**   1. the legacy format, that may be read by all fts5 versions, and
+**
+**   2. the V2 format, which is used by contentless_delete=1 databases.
+**
+** Both begin with a 4-byte "configuration cookie" value. Then, a legacy
+** format structure record contains a varint - the number of levels in
+** the structure. Whereas a V2 structure record contains the constant
+** 4 bytes [0xff 0x00 0x00 0x01]. This is unambiguous as the value of a
+** varint has to be at least 16256 to begin with "0xFF". And the default
+** maximum number of levels is 64.
+**
+** See below for more on structure record formats.
+*/
+#define FTS5_STRUCTURE_V2 "\xFF\x00\x00\x01"
+
+/*
+** Details:
+**
+** The %_data table managed by this module,
+**
+**     CREATE TABLE %_data(id INTEGER PRIMARY KEY, block BLOB);
+**
+** , contains the following 6 types of records. See the comments surrounding
+** the FTS5_*_ROWID macros below for a description of how %_data rowids are
+** assigned to each fo them.
+**
+** 1. Structure Records:
+**
+**   The set of segments that make up an index - the index structure - are
+**   recorded in a single record within the %_data table. The record consists
+**   of a single 32-bit configuration cookie value followed by a list of
+**   SQLite varints.
+**
+**   If the structure record is a V2 record, the configuration cookie is
+**   followed by the following 4 bytes: [0xFF 0x00 0x00 0x01].
+**
+**   Next, the record continues with three varints:
+**
+**     + number of levels,
+**     + total number of segments on all levels,
+**     + value of write counter.
+**
+**   Then, for each level from 0 to nMax:
+**
+**     + number of input segments in ongoing merge.
+**     + total number of segments in level.
+**     + for each segment from oldest to newest:
+**         + segment id (always > 0)
+**         + first leaf page number (often 1, always greater than 0)
+**         + final leaf page number
+**
+**      Then, for V2 structures only:
+**
+**         + lower origin counter value,
+**         + upper origin counter value,
+**         + the number of tombstone hash pages.
+**
+** 2. The Averages Record:
+**
+**   A single record within the %_data table. The data is a list of varints.
+**   The first value is the number of rows in the index. Then, for each column
+**   from left to right, the total number of tokens in the column for all
+**   rows of the table.
+**
+** 3. Segment leaves:
+**
+**   TERM/DOCLIST FORMAT:
+**
+**     Most of each segment leaf is taken up by term/doclist data. The
+**     general format of term/doclist, starting with the first term
+**     on the leaf page, is:
+**
+**         varint : size of first term
+**         blob:    first term data
+**         doclist: first doclist
+**         zero-or-more {
+**           varint:  number of bytes in common with previous term
+**           varint:  number of bytes of new term data (nNew)
+**           blob:    nNew bytes of new term data
+**           doclist: next doclist
+**         }
+**
+**     doclist format:
+**
+**         varint:  first rowid
+**         poslist: first poslist
+**         zero-or-more {
+**           varint:  rowid delta (always > 0)
+**           poslist: next poslist
+**         }
+**
+**     poslist format:
+**
+**         varint: size of poslist in bytes multiplied by 2, not including
+**                 this field. Plus 1 if this entry carries the "delete" flag.
+**         collist: collist for column 0
+**         zero-or-more {
+**           0x01 byte
+**           varint: column number (I)
+**           collist: collist for column I
+**         }
+**
+**     collist format:
+**
+**         varint: first offset + 2
+**         zero-or-more {
+**           varint: offset delta + 2
+**         }
+**
+**   PAGE FORMAT
+**
+**     Each leaf page begins with a 4-byte header containing 2 16-bit
+**     unsigned integer fields in big-endian format. They are:
+**
+**       * The byte offset of the first rowid on the page, if it exists
+**         and occurs before the first term (otherwise 0).
+**
+**       * The byte offset of the start of the page footer. If the page
+**         footer is 0 bytes in size, then this field is the same as the
+**         size of the leaf page in bytes.
+**
+**     The page footer consists of a single varint for each term located
+**     on the page. Each varint is the byte offset of the current term
+**     within the page, delta-compressed against the previous value. In
+**     other words, the first varint in the footer is the byte offset of
+**     the first term, the second is the byte offset of the second less that
+**     of the first, and so on.
+**
+**     The term/doclist format described above is accurate if the entire
+**     term/doclist data fits on a single leaf page. If this is not the case,
+**     the format is changed in two ways:
+**
+**       + if the first rowid on a page occurs before the first term, it
+**         is stored as a literal value:
+**
+**             varint:  first rowid
+**
+**       + the first term on each page is stored in the same way as the
+**         very first term of the segment:
+**
+**             varint : size of first term
+**             blob:    first term data
+**
+** 5. Segment doclist indexes:
+**
+**   Doclist indexes are themselves b-trees, however they usually consist of
+**   a single leaf record only. The format of each doclist index leaf page
+**   is:
+**
+**     * Flags byte. Bits are:
+**         0x01: Clear if leaf is also the root page, otherwise set.
+**
+**     * Page number of fts index leaf page. As a varint.
+**
+**     * First rowid on page indicated by previous field. As a varint.
+**
+**     * A list of varints, one for each subsequent termless page. A
+**       positive delta if the termless page contains at least one rowid,
+**       or an 0x00 byte otherwise.
+**
+**   Internal doclist index nodes are:
+**
+**     * Flags byte. Bits are:
+**         0x01: Clear for root page, otherwise set.
+**
+**     * Page number of first child page. As a varint.
+**
+**     * Copy of first rowid on page indicated by previous field. As a varint.
+**
+**     * A list of delta-encoded varints - the first rowid on each subsequent
+**       child page.
+**
+** 6. Tombstone Hash Page
+**
+**   These records are only ever present in contentless_delete=1 tables.
+**   There are zero or more of these associated with each segment. They
+**   are used to store the tombstone rowids for rows contained in the
+**   associated segments.
+**
+**   The set of nHashPg tombstone hash pages associated with a single
+**   segment together form a single hash table containing tombstone rowids.
+**   To find the page of the hash on which a key might be stored:
+**
+**       iPg = (rowid % nHashPg)
+**
+**   Then, within page iPg, which has nSlot slots:
+**
+**       iSlot = (rowid / nHashPg) % nSlot
+**
+**   Each tombstone hash page begins with an 8 byte header:
+**
+**     1-byte:  Key-size (the size in bytes of each slot). Either 4 or 8.
+**     1-byte:  rowid-0-tombstone flag. This flag is only valid on the
+**              first tombstone hash page for each segment (iPg=0). If set,
+**              the hash table contains rowid 0. If clear, it does not.
+**              Rowid 0 is handled specially.
+**     2-bytes: unused.
+**     4-bytes: Big-endian integer containing number of entries on page.
+**
+**   Following this are nSlot 4 or 8 byte slots (depending on the key-size
+**   in the first byte of the page header). The number of slots may be
+**   determined based on the size of the page record and the key-size:
+**
+**     nSlot = (nByte - 8) / key-size
+*/
+
+/*
+** Rowids for the averages and structure records in the %_data table.
+*/
+#define FTS5_AVERAGES_ROWID     1    /* Rowid used for the averages record */
+#define FTS5_STRUCTURE_ROWID   10    /* The structure record */
+
+/*
+** Macros determining the rowids used by segment leaves and dlidx leaves
+** and nodes. All nodes and leaves are stored in the %_data table with large
+** positive rowids.
+**
+** Each segment has a unique non-zero 16-bit id.
+**
+** The rowid for each segment leaf is found by passing the segment id and
+** the leaf page number to the FTS5_SEGMENT_ROWID macro. Leaves are numbered
+** sequentially starting from 1.
+*/
+#define FTS5_DATA_ID_B     16     /* Max seg id number 65535 */
+#define FTS5_DATA_DLI_B     1     /* Doclist-index flag (1 bit) */
+#define FTS5_DATA_HEIGHT_B  5     /* Max dlidx tree height of 32 */
+#define FTS5_DATA_PAGE_B   31     /* Max page number of 2147483648 */
+
+#define fts5_dri(segid, dlidx, height, pgno) (                                 \
+ ((i64)(segid)  << (FTS5_DATA_PAGE_B+FTS5_DATA_HEIGHT_B+FTS5_DATA_DLI_B)) +    \
+ ((i64)(dlidx)  << (FTS5_DATA_PAGE_B + FTS5_DATA_HEIGHT_B)) +                  \
+ ((i64)(height) << (FTS5_DATA_PAGE_B)) +                                       \
+ ((i64)(pgno))                                                                 \
+)
+
+#define FTS5_SEGMENT_ROWID(segid, pgno)       fts5_dri(segid, 0, 0, pgno)
+#define FTS5_DLIDX_ROWID(segid, height, pgno) fts5_dri(segid, 1, height, pgno)
+#define FTS5_TOMBSTONE_ROWID(segid,ipg)       fts5_dri(segid+(1<<16), 0, 0, ipg)
+
+#ifdef SQLITE_DEBUG
+static int sqlite3Fts5Corrupt() { return SQLITE_CORRUPT_VTAB; }
+#endif
+
+
+/*
+** Each time a blob is read from the %_data table, it is padded with this
+** many zero bytes. This makes it easier to decode the various record formats
+** without overreading if the records are corrupt.
+*/
+#define FTS5_DATA_ZERO_PADDING 8
+#define FTS5_DATA_PADDING 20
+
+typedef struct Fts5Data Fts5Data;
+typedef struct Fts5DlidxIter Fts5DlidxIter;
+typedef struct Fts5DlidxLvl Fts5DlidxLvl;
+typedef struct Fts5DlidxWriter Fts5DlidxWriter;
+typedef struct Fts5Iter Fts5Iter;
+typedef struct Fts5PageWriter Fts5PageWriter;
+typedef struct Fts5SegIter Fts5SegIter;
+typedef struct Fts5DoclistIter Fts5DoclistIter;
+typedef struct Fts5SegWriter Fts5SegWriter;
+typedef struct Fts5Structure Fts5Structure;
+typedef struct Fts5StructureLevel Fts5StructureLevel;
+typedef struct Fts5StructureSegment Fts5StructureSegment;
+typedef struct Fts5TokenDataIter Fts5TokenDataIter;
+typedef struct Fts5TokenDataMap Fts5TokenDataMap;
+typedef struct Fts5TombstoneArray Fts5TombstoneArray;
+
+struct Fts5Data {
+  u8 *p;                          /* Pointer to buffer containing record */
+  int nn;                         /* Size of record in bytes */
+  int szLeaf;                     /* Size of leaf without page-index */
+};
+
+/*
+** One object per %_data table.
+**
+** nContentlessDelete:
+**   The number of contentless delete operations since the most recent
+**   call to fts5IndexFlush() or fts5IndexDiscardData(). This is tracked
+**   so that extra auto-merge work can be done by fts5IndexFlush() to
+**   account for the delete operations.
+*/
+struct Fts5Index {
+  Fts5Config *pConfig;            /* Virtual table configuration */
+  char *zDataTbl;                 /* Name of %_data table */
+  int nWorkUnit;                  /* Leaf pages in a "unit" of work */
+
+  /*
+  ** Variables related to the accumulation of tokens and doclists within the
+  ** in-memory hash tables before they are flushed to disk.
+  */
+  Fts5Hash *pHash;                /* Hash table for in-memory data */
+  int nPendingData;               /* Current bytes of pending data */
+  i64 iWriteRowid;                /* Rowid for current doc being written */
+  int bDelete;                    /* Current write is a delete */
+  int nContentlessDelete;         /* Number of contentless delete ops */
+  int nPendingRow;                /* Number of INSERT in hash table */
+
+  /* Error state. */
+  int rc;                         /* Current error code */
+  int flushRc;
+
+  /* State used by the fts5DataXXX() functions. */
+  sqlite3_blob *pReader;          /* RO incr-blob open on %_data table */
+  sqlite3_stmt *pWriter;          /* "INSERT ... %_data VALUES(?,?)" */
+  sqlite3_stmt *pDeleter;         /* "DELETE FROM %_data ... id>=? AND id<=?" */
+  sqlite3_stmt *pIdxWriter;       /* "INSERT ... %_idx VALUES(?,?,?,?)" */
+  sqlite3_stmt *pIdxDeleter;      /* "DELETE FROM %_idx WHERE segid=?" */
+  sqlite3_stmt *pIdxSelect;
+  sqlite3_stmt *pIdxNextSelect;
+  int nRead;                      /* Total number of blocks read */
+
+  sqlite3_stmt *pDeleteFromIdx;
+
+  sqlite3_stmt *pDataVersion;
+  i64 iStructVersion;             /* data_version when pStruct read */
+  Fts5Structure *pStruct;         /* Current db structure (or NULL) */
+};
+
+struct Fts5DoclistIter {
+  u8 *aEof;                       /* Pointer to 1 byte past end of doclist */
+
+  /* Output variables. aPoslist==0 at EOF */
+  i64 iRowid;
+  u8 *aPoslist;
+  int nPoslist;
+  int nSize;
+};
+
+/*
+** The contents of the "structure" record for each index are represented
+** using an Fts5Structure record in memory. Which uses instances of the
+** other Fts5StructureXXX types as components.
+**
+** nOriginCntr:
+**   This value is set to non-zero for structure records created for
+**   contentlessdelete=1 tables only. In that case it represents the
+**   origin value to apply to the next top-level segment created.
+*/
+struct Fts5StructureSegment {
+  int iSegid;                     /* Segment id */
+  int pgnoFirst;                  /* First leaf page number in segment */
+  int pgnoLast;                   /* Last leaf page number in segment */
+
+  /* contentlessdelete=1 tables only: */
+  u64 iOrigin1;
+  u64 iOrigin2;
+  int nPgTombstone;               /* Number of tombstone hash table pages */
+  u64 nEntryTombstone;            /* Number of tombstone entries that "count" */
+  u64 nEntry;                     /* Number of rows in this segment */
+};
+struct Fts5StructureLevel {
+  int nMerge;                     /* Number of segments in incr-merge */
+  int nSeg;                       /* Total number of segments on level */
+  Fts5StructureSegment *aSeg;     /* Array of segments. aSeg[0] is oldest. */
+};
+struct Fts5Structure {
+  int nRef;                       /* Object reference count */
+  u64 nWriteCounter;              /* Total leaves written to level 0 */
+  u64 nOriginCntr;                /* Origin value for next top-level segment */
+  int nSegment;                   /* Total segments in this structure */
+  int nLevel;                     /* Number of levels in this index */
+  Fts5StructureLevel aLevel[1];   /* Array of nLevel level objects */
+};
+
+/*
+** An object of type Fts5SegWriter is used to write to segments.
+*/
+struct Fts5PageWriter {
+  int pgno;                       /* Page number for this page */
+  int iPrevPgidx;                 /* Previous value written into pgidx */
+  Fts5Buffer buf;                 /* Buffer containing leaf data */
+  Fts5Buffer pgidx;               /* Buffer containing page-index */
+  Fts5Buffer term;                /* Buffer containing previous term on page */
+};
+struct Fts5DlidxWriter {
+  int pgno;                       /* Page number for this page */
+  int bPrevValid;                 /* True if iPrev is valid */
+  i64 iPrev;                      /* Previous rowid value written to page */
+  Fts5Buffer buf;                 /* Buffer containing page data */
+};
+struct Fts5SegWriter {
+  int iSegid;                     /* Segid to write to */
+  Fts5PageWriter writer;          /* PageWriter object */
+  i64 iPrevRowid;                 /* Previous rowid written to current leaf */
+  u8 bFirstRowidInDoclist;        /* True if next rowid is first in doclist */
+  u8 bFirstRowidInPage;           /* True if next rowid is first in page */
+  /* TODO1: Can use (writer.pgidx.n==0) instead of bFirstTermInPage */
+  u8 bFirstTermInPage;            /* True if next term will be first in leaf */
+  int nLeafWritten;               /* Number of leaf pages written */
+  int nEmpty;                     /* Number of contiguous term-less nodes */
+
+  int nDlidx;                     /* Allocated size of aDlidx[] array */
+  Fts5DlidxWriter *aDlidx;        /* Array of Fts5DlidxWriter objects */
+
+  /* Values to insert into the %_idx table */
+  Fts5Buffer btterm;              /* Next term to insert into %_idx table */
+  int iBtPage;                    /* Page number corresponding to btterm */
+};
+
+typedef struct Fts5CResult Fts5CResult;
+struct Fts5CResult {
+  u16 iFirst;                     /* aSeg[] index of firstest iterator */
+  u8 bTermEq;                     /* True if the terms are equal */
+};
+
+/*
+** Object for iterating through a single segment, visiting each term/rowid
+** pair in the segment.
+**
+** pSeg:
+**   The segment to iterate through.
+**
+** iLeafPgno:
+**   Current leaf page number within segment.
+**
+** iLeafOffset:
+**   Byte offset within the current leaf that is the first byte of the
+**   position list data (one byte passed the position-list size field).
+**
+** pLeaf:
+**   Buffer containing current leaf page data. Set to NULL at EOF.
+**
+** iTermLeafPgno, iTermLeafOffset:
+**   Leaf page number containing the last term read from the segment. And
+**   the offset immediately following the term data.
+**
+** flags:
+**   Mask of FTS5_SEGITER_XXX values. Interpreted as follows:
+**
+**   FTS5_SEGITER_ONETERM:
+**     If set, set the iterator to point to EOF after the current doclist
+**     has been exhausted. Do not proceed to the next term in the segment.
+**
+**   FTS5_SEGITER_REVERSE:
+**     This flag is only ever set if FTS5_SEGITER_ONETERM is also set. If
+**     it is set, iterate through rowid in descending order instead of the
+**     default ascending order.
+**
+** iRowidOffset/nRowidOffset/aRowidOffset:
+**     These are used if the FTS5_SEGITER_REVERSE flag is set.
+**
+**     For each rowid on the page corresponding to the current term, the
+**     corresponding aRowidOffset[] entry is set to the byte offset of the
+**     start of the "position-list-size" field within the page.
+**
+** iTermIdx:
+**     Index of current term on iTermLeafPgno.
+**
+** apTombstone/nTombstone:
+**     These are used for contentless_delete=1 tables only. When the cursor
+**     is first allocated, the apTombstone[] array is allocated so that it
+**     is large enough for all tombstones hash pages associated with the
+**     segment. The pages themselves are loaded lazily from the database as
+**     they are required.
+*/
+struct Fts5SegIter {
+  Fts5StructureSegment *pSeg;     /* Segment to iterate through */
+  int flags;                      /* Mask of configuration flags */
+  int iLeafPgno;                  /* Current leaf page number */
+  Fts5Data *pLeaf;                /* Current leaf data */
+  Fts5Data *pNextLeaf;            /* Leaf page (iLeafPgno+1) */
+  i64 iLeafOffset;                /* Byte offset within current leaf */
+  Fts5TombstoneArray *pTombArray; /* Array of tombstone pages */
+
+  /* Next method */
+  void (*xNext)(Fts5Index*, Fts5SegIter*, int*);
+
+  /* The page and offset from which the current term was read. The offset
+  ** is the offset of the first rowid in the current doclist.  */
+  int iTermLeafPgno;
+  int iTermLeafOffset;
+
+  int iPgidxOff;                  /* Next offset in pgidx */
+  int iEndofDoclist;
+
+  /* The following are only used if the FTS5_SEGITER_REVERSE flag is set. */
+  int iRowidOffset;               /* Current entry in aRowidOffset[] */
+  int nRowidOffset;               /* Allocated size of aRowidOffset[] array */
+  int *aRowidOffset;              /* Array of offset to rowid fields */
+
+  Fts5DlidxIter *pDlidx;          /* If there is a doclist-index */
+
+  /* Variables populated based on current entry. */
+  Fts5Buffer term;                /* Current term */
+  i64 iRowid;                     /* Current rowid */
+  int nPos;                       /* Number of bytes in current position list */
+  u8 bDel;                        /* True if the delete flag is set */
+};
+
+/*
+** Array of tombstone pages. Reference counted.
+*/
+struct Fts5TombstoneArray {
+  int nRef;                       /* Number of pointers to this object */
+  int nTombstone;
+  Fts5Data *apTombstone[1];       /* Array of tombstone pages */
+};
+
+/*
+** Argument is a pointer to an Fts5Data structure that contains a
+** leaf page.
+*/
+#define ASSERT_SZLEAF_OK(x) assert( \
+    (x)->szLeaf==(x)->nn || (x)->szLeaf==fts5GetU16(&(x)->p[2]) \
+)
+
+#define FTS5_SEGITER_ONETERM 0x01
+#define FTS5_SEGITER_REVERSE 0x02
+
+/*
+** Argument is a pointer to an Fts5Data structure that contains a leaf
+** page. This macro evaluates to true if the leaf contains no terms, or
+** false if it contains at least one term.
+*/
+#define fts5LeafIsTermless(x) ((x)->szLeaf >= (x)->nn)
+
+#define fts5LeafTermOff(x, i) (fts5GetU16(&(x)->p[(x)->szLeaf + (i)*2]))
+
+#define fts5LeafFirstRowidOff(x) (fts5GetU16((x)->p))
+
+/*
+** Object for iterating through the merged results of one or more segments,
+** visiting each term/rowid pair in the merged data.
+**
+** nSeg is always a power of two greater than or equal to the number of
+** segments that this object is merging data from. Both the aSeg[] and
+** aFirst[] arrays are sized at nSeg entries. The aSeg[] array is padded
+** with zeroed objects - these are handled as if they were iterators opened
+** on empty segments.
+**
+** The results of comparing segments aSeg[N] and aSeg[N+1], where N is an
+** even number, is stored in aFirst[(nSeg+N)/2]. The "result" of the
+** comparison in this context is the index of the iterator that currently
+** points to the smaller term/rowid combination. Iterators at EOF are
+** considered to be greater than all other iterators.
+**
+** aFirst[1] contains the index in aSeg[] of the iterator that points to
+** the smallest key overall. aFirst[0] is unused.
+**
+** poslist:
+**   Used by sqlite3Fts5IterPoslist() when the poslist needs to be buffered.
+**   There is no way to tell if this is populated or not.
+**
+** pColset:
+**   If not NULL, points to an object containing a set of column indices.
+**   Only matches that occur in one of these columns will be returned.
+**   The Fts5Iter does not own the Fts5Colset object, and so it is not
+**   freed when the iterator is closed - it is owned by the upper layer.
+*/
+struct Fts5Iter {
+  Fts5IndexIter base;             /* Base class containing output vars */
+  Fts5TokenDataIter *pTokenDataIter;
+
+  Fts5Index *pIndex;              /* Index that owns this iterator */
+  Fts5Buffer poslist;             /* Buffer containing current poslist */
+  Fts5Colset *pColset;            /* Restrict matches to these columns */
+
+  /* Invoked to set output variables. */
+  void (*xSetOutputs)(Fts5Iter*, Fts5SegIter*);
+
+  int nSeg;                       /* Size of aSeg[] array */
+  int bRev;                       /* True to iterate in reverse order */
+  u8 bSkipEmpty;                  /* True to skip deleted entries */
+
+  i64 iSwitchRowid;               /* Firstest rowid of other than aFirst[1] */
+  Fts5CResult *aFirst;            /* Current merge state (see above) */
+  Fts5SegIter aSeg[1];            /* Array of segment iterators */
+};
+
+/*
+** An instance of the following type is used to iterate through the contents
+** of a doclist-index record.
+**
+** pData:
+**   Record containing the doclist-index data.
+**
+** bEof:
+**   Set to true once iterator has reached EOF.
+**
+** iOff:
+**   Set to the current offset within record pData.
+*/
+struct Fts5DlidxLvl {
+  Fts5Data *pData;              /* Data for current page of this level */
+  int iOff;                     /* Current offset into pData */
+  int bEof;                     /* At EOF already */
+  int iFirstOff;                /* Used by reverse iterators */
+
+  /* Output variables */
+  int iLeafPgno;                /* Page number of current leaf page */
+  i64 iRowid;                   /* First rowid on leaf iLeafPgno */
+};
+struct Fts5DlidxIter {
+  int nLvl;
+  int iSegid;
+  Fts5DlidxLvl aLvl[1];
+};
+
+static void fts5PutU16(u8 *aOut, u16 iVal){
+  aOut[0] = (iVal>>8);
+  aOut[1] = (iVal&0xFF);
+}
+
+static u16 fts5GetU16(const u8 *aIn){
+  return ((u16)aIn[0] << 8) + aIn[1];
+}
+
+/*
+** The only argument points to a buffer at least 8 bytes in size. This
+** function interprets the first 8 bytes of the buffer as a 64-bit big-endian
+** unsigned integer and returns the result.
+*/
+static u64 fts5GetU64(u8 *a){
+  return ((u64)a[0] << 56)
+       + ((u64)a[1] << 48)
+       + ((u64)a[2] << 40)
+       + ((u64)a[3] << 32)
+       + ((u64)a[4] << 24)
+       + ((u64)a[5] << 16)
+       + ((u64)a[6] << 8)
+       + ((u64)a[7] << 0);
+}
+
+/*
+** The only argument points to a buffer at least 4 bytes in size. This
+** function interprets the first 4 bytes of the buffer as a 32-bit big-endian
+** unsigned integer and returns the result.
+*/
+static u32 fts5GetU32(const u8 *a){
+  return ((u32)a[0] << 24)
+       + ((u32)a[1] << 16)
+       + ((u32)a[2] << 8)
+       + ((u32)a[3] << 0);
+}
+
+/*
+** Write iVal, formated as a 64-bit big-endian unsigned integer, to the
+** buffer indicated by the first argument.
+*/
+static void fts5PutU64(u8 *a, u64 iVal){
+  a[0] = ((iVal >> 56) & 0xFF);
+  a[1] = ((iVal >> 48) & 0xFF);
+  a[2] = ((iVal >> 40) & 0xFF);
+  a[3] = ((iVal >> 32) & 0xFF);
+  a[4] = ((iVal >> 24) & 0xFF);
+  a[5] = ((iVal >> 16) & 0xFF);
+  a[6] = ((iVal >>  8) & 0xFF);
+  a[7] = ((iVal >>  0) & 0xFF);
+}
+
+/*
+** Write iVal, formated as a 32-bit big-endian unsigned integer, to the
+** buffer indicated by the first argument.
+*/
+static void fts5PutU32(u8 *a, u32 iVal){
+  a[0] = ((iVal >> 24) & 0xFF);
+  a[1] = ((iVal >> 16) & 0xFF);
+  a[2] = ((iVal >>  8) & 0xFF);
+  a[3] = ((iVal >>  0) & 0xFF);
+}
+
+/*
+** Allocate and return a buffer at least nByte bytes in size.
+**
+** If an OOM error is encountered, return NULL and set the error code in
+** the Fts5Index handle passed as the first argument.
+*/
+static void *fts5IdxMalloc(Fts5Index *p, sqlite3_int64 nByte){
+  return sqlite3Fts5MallocZero(&p->rc, nByte);
+}
+
+/*
+** Compare the contents of the pLeft buffer with the pRight/nRight blob.
+**
+** Return -ve if pLeft is smaller than pRight, 0 if they are equal or
+** +ve if pRight is smaller than pLeft. In other words:
+**
+**     res = *pLeft - *pRight
+*/
+#ifdef SQLITE_DEBUG
+static int fts5BufferCompareBlob(
+  Fts5Buffer *pLeft,              /* Left hand side of comparison */
+  const u8 *pRight, int nRight    /* Right hand side of comparison */
+){
+  int nCmp = MIN(pLeft->n, nRight);
+  int res = memcmp(pLeft->p, pRight, nCmp);
+  return (res==0 ? (pLeft->n - nRight) : res);
+}
+#endif
+
+/*
+** Compare the contents of the two buffers using memcmp(). If one buffer
+** is a prefix of the other, it is considered the lesser.
+**
+** Return -ve if pLeft is smaller than pRight, 0 if they are equal or
+** +ve if pRight is smaller than pLeft. In other words:
+**
+**     res = *pLeft - *pRight
+*/
+static int fts5BufferCompare(Fts5Buffer *pLeft, Fts5Buffer *pRight){
+  int nCmp, res;
+  nCmp = MIN(pLeft->n, pRight->n);
+  assert( nCmp<=0 || pLeft->p!=0 );
+  assert( nCmp<=0 || pRight->p!=0 );
+  res = fts5Memcmp(pLeft->p, pRight->p, nCmp);
+  return (res==0 ? (pLeft->n - pRight->n) : res);
+}
+
+static int fts5LeafFirstTermOff(Fts5Data *pLeaf){
+  int ret;
+  fts5GetVarint32(&pLeaf->p[pLeaf->szLeaf], ret);
+  return ret;
+}
+
+/*
+** Close the read-only blob handle, if it is open.
+*/
+static void fts5IndexCloseReader(Fts5Index *p){
+  if( p->pReader ){
+    int rc;
+    sqlite3_blob *pReader = p->pReader;
+    p->pReader = 0;
+    rc = sqlite3_blob_close(pReader);
+    if( p->rc==SQLITE_OK ) p->rc = rc;
+  }
+}
+
+/*
+** Retrieve a record from the %_data table.
+**
+** If an error occurs, NULL is returned and an error left in the
+** Fts5Index object.
+*/
+static Fts5Data *fts5DataRead(Fts5Index *p, i64 iRowid){
+  Fts5Data *pRet = 0;
+  if( p->rc==SQLITE_OK ){
+    int rc = SQLITE_OK;
+
+    if( p->pReader ){
+      /* This call may return SQLITE_ABORT if there has been a savepoint
+      ** rollback since it was last used. In this case a new blob handle
+      ** is required.  */
+      sqlite3_blob *pBlob = p->pReader;
+      p->pReader = 0;
+      rc = sqlite3_blob_reopen(pBlob, iRowid);
+      assert( p->pReader==0 );
+      p->pReader = pBlob;
+      if( rc!=SQLITE_OK ){
+        fts5IndexCloseReader(p);
+      }
+      if( rc==SQLITE_ABORT ) rc = SQLITE_OK;
+    }
+
+    /* If the blob handle is not open at this point, open it and seek
+    ** to the requested entry.  */
+    if( p->pReader==0 && rc==SQLITE_OK ){
+      Fts5Config *pConfig = p->pConfig;
+      rc = sqlite3_blob_open(pConfig->db,
+          pConfig->zDb, p->zDataTbl, "block", iRowid, 0, &p->pReader
+      );
+    }
+
+    /* If either of the sqlite3_blob_open() or sqlite3_blob_reopen() calls
+    ** above returned SQLITE_ERROR, return SQLITE_CORRUPT_VTAB instead.
+    ** All the reasons those functions might return SQLITE_ERROR - missing
+    ** table, missing row, non-blob/text in block column - indicate
+    ** backing store corruption.  */
+    if( rc==SQLITE_ERROR ) rc = FTS5_CORRUPT;
+
+    if( rc==SQLITE_OK ){
+      u8 *aOut = 0;               /* Read blob data into this buffer */
+      int nByte = sqlite3_blob_bytes(p->pReader);
+      int szData = (sizeof(Fts5Data) + 7) & ~7;
+      sqlite3_int64 nAlloc = szData + nByte + FTS5_DATA_PADDING;
+      pRet = (Fts5Data*)sqlite3_malloc64(nAlloc);
+      if( pRet ){
+        pRet->nn = nByte;
+        aOut = pRet->p = (u8*)pRet + szData;
+      }else{
+        rc = SQLITE_NOMEM;
+      }
+
+      if( rc==SQLITE_OK ){
+        rc = sqlite3_blob_read(p->pReader, aOut, nByte, 0);
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3_free(pRet);
+        pRet = 0;
+      }else{
+        /* TODO1: Fix this */
+        pRet->p[nByte] = 0x00;
+        pRet->p[nByte+1] = 0x00;
+        pRet->szLeaf = fts5GetU16(&pRet->p[2]);
+      }
+    }
+    p->rc = rc;
+    p->nRead++;
+  }
+
+  assert( (pRet==0)==(p->rc!=SQLITE_OK) );
+  assert( pRet==0 || EIGHT_BYTE_ALIGNMENT( pRet->p ) );
+  return pRet;
+}
+
+
+/*
+** Release a reference to data record returned by an earlier call to
+** fts5DataRead().
+*/
+static void fts5DataRelease(Fts5Data *pData){
+  sqlite3_free(pData);
+}
+
+static Fts5Data *fts5LeafRead(Fts5Index *p, i64 iRowid){
+  Fts5Data *pRet = fts5DataRead(p, iRowid);
+  if( pRet ){
+    if( pRet->nn<4 || pRet->szLeaf>pRet->nn ){
+      p->rc = FTS5_CORRUPT;
+      fts5DataRelease(pRet);
+      pRet = 0;
+    }
+  }
+  return pRet;
+}
+
+static int fts5IndexPrepareStmt(
+  Fts5Index *p,
+  sqlite3_stmt **ppStmt,
+  char *zSql
+){
+  if( p->rc==SQLITE_OK ){
+    if( zSql ){
+      int rc = sqlite3_prepare_v3(p->pConfig->db, zSql, -1,
+          SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB,
+          ppStmt, 0);
+      /* If this prepare() call fails with SQLITE_ERROR, then one of the
+      ** %_idx or %_data tables has been removed or modified. Call this
+      ** corruption.  */
+      p->rc = (rc==SQLITE_ERROR ? SQLITE_CORRUPT : rc);
+    }else{
+      p->rc = SQLITE_NOMEM;
+    }
+  }
+  sqlite3_free(zSql);
+  return p->rc;
+}
+
+
+/*
+** INSERT OR REPLACE a record into the %_data table.
+*/
+static void fts5DataWrite(Fts5Index *p, i64 iRowid, const u8 *pData, int nData){
+  if( p->rc!=SQLITE_OK ) return;
+
+  if( p->pWriter==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pWriter, sqlite3_mprintf(
+          "REPLACE INTO '%q'.'%q_data'(id, block) VALUES(?,?)",
+          pConfig->zDb, pConfig->zName
+    ));
+    if( p->rc ) return;
+  }
+
+  sqlite3_bind_int64(p->pWriter, 1, iRowid);
+  sqlite3_bind_blob(p->pWriter, 2, pData, nData, SQLITE_STATIC);
+  sqlite3_step(p->pWriter);
+  p->rc = sqlite3_reset(p->pWriter);
+  sqlite3_bind_null(p->pWriter, 2);
+}
+
+/*
+** Execute the following SQL:
+**
+**     DELETE FROM %_data WHERE id BETWEEN $iFirst AND $iLast
+*/
+static void fts5DataDelete(Fts5Index *p, i64 iFirst, i64 iLast){
+  if( p->rc!=SQLITE_OK ) return;
+
+  if( p->pDeleter==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    char *zSql = sqlite3_mprintf(
+        "DELETE FROM '%q'.'%q_data' WHERE id>=? AND id<=?",
+          pConfig->zDb, pConfig->zName
+    );
+    if( fts5IndexPrepareStmt(p, &p->pDeleter, zSql) ) return;
+  }
+
+  sqlite3_bind_int64(p->pDeleter, 1, iFirst);
+  sqlite3_bind_int64(p->pDeleter, 2, iLast);
+  sqlite3_step(p->pDeleter);
+  p->rc = sqlite3_reset(p->pDeleter);
+}
+
+/*
+** Remove all records associated with segment iSegid.
+*/
+static void fts5DataRemoveSegment(Fts5Index *p, Fts5StructureSegment *pSeg){
+  int iSegid = pSeg->iSegid;
+  i64 iFirst = FTS5_SEGMENT_ROWID(iSegid, 0);
+  i64 iLast = FTS5_SEGMENT_ROWID(iSegid+1, 0)-1;
+  fts5DataDelete(p, iFirst, iLast);
+
+  if( pSeg->nPgTombstone ){
+    i64 iTomb1 = FTS5_TOMBSTONE_ROWID(iSegid, 0);
+    i64 iTomb2 = FTS5_TOMBSTONE_ROWID(iSegid, pSeg->nPgTombstone-1);
+    fts5DataDelete(p, iTomb1, iTomb2);
+  }
+  if( p->pIdxDeleter==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pIdxDeleter, sqlite3_mprintf(
+          "DELETE FROM '%q'.'%q_idx' WHERE segid=?",
+          pConfig->zDb, pConfig->zName
+    ));
+  }
+  if( p->rc==SQLITE_OK ){
+    sqlite3_bind_int(p->pIdxDeleter, 1, iSegid);
+    sqlite3_step(p->pIdxDeleter);
+    p->rc = sqlite3_reset(p->pIdxDeleter);
+  }
+}
+
+/*
+** Release a reference to an Fts5Structure object returned by an earlier
+** call to fts5StructureRead() or fts5StructureDecode().
+*/
+static void fts5StructureRelease(Fts5Structure *pStruct){
+  if( pStruct && 0>=(--pStruct->nRef) ){
+    int i;
+    assert( pStruct->nRef==0 );
+    for(i=0; i<pStruct->nLevel; i++){
+      sqlite3_free(pStruct->aLevel[i].aSeg);
+    }
+    sqlite3_free(pStruct);
+  }
+}
+
+static void fts5StructureRef(Fts5Structure *pStruct){
+  pStruct->nRef++;
+}
+
+static void *sqlite3Fts5StructureRef(Fts5Index *p){
+  fts5StructureRef(p->pStruct);
+  return (void*)p->pStruct;
+}
+static void sqlite3Fts5StructureRelease(void *p){
+  if( p ){
+    fts5StructureRelease((Fts5Structure*)p);
+  }
+}
+static int sqlite3Fts5StructureTest(Fts5Index *p, void *pStruct){
+  if( p->pStruct!=(Fts5Structure*)pStruct ){
+    return SQLITE_ABORT;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Ensure that structure object (*pp) is writable.
+**
+** This function is a no-op if (*pRc) is not SQLITE_OK when it is called. If
+** an error occurs, (*pRc) is set to an SQLite error code before returning.
+*/
+static void fts5StructureMakeWritable(int *pRc, Fts5Structure **pp){
+  Fts5Structure *p = *pp;
+  if( *pRc==SQLITE_OK && p->nRef>1 ){
+    i64 nByte = sizeof(Fts5Structure)+(p->nLevel-1)*sizeof(Fts5StructureLevel);
+    Fts5Structure *pNew;
+    pNew = (Fts5Structure*)sqlite3Fts5MallocZero(pRc, nByte);
+    if( pNew ){
+      int i;
+      memcpy(pNew, p, nByte);
+      for(i=0; i<p->nLevel; i++) pNew->aLevel[i].aSeg = 0;
+      for(i=0; i<p->nLevel; i++){
+        Fts5StructureLevel *pLvl = &pNew->aLevel[i];
+        nByte = sizeof(Fts5StructureSegment) * pNew->aLevel[i].nSeg;
+        pLvl->aSeg = (Fts5StructureSegment*)sqlite3Fts5MallocZero(pRc, nByte);
+        if( pLvl->aSeg==0 ){
+          for(i=0; i<p->nLevel; i++){
+            sqlite3_free(pNew->aLevel[i].aSeg);
+          }
+          sqlite3_free(pNew);
+          return;
+        }
+        memcpy(pLvl->aSeg, p->aLevel[i].aSeg, nByte);
+      }
+      p->nRef--;
+      pNew->nRef = 1;
+    }
+    *pp = pNew;
+  }
+}
+
+/*
+** Deserialize and return the structure record currently stored in serialized
+** form within buffer pData/nData.
+**
+** The Fts5Structure.aLevel[] and each Fts5StructureLevel.aSeg[] array
+** are over-allocated by one slot. This allows the structure contents
+** to be more easily edited.
+**
+** If an error occurs, *ppOut is set to NULL and an SQLite error code
+** returned. Otherwise, *ppOut is set to point to the new object and
+** SQLITE_OK returned.
+*/
+static int fts5StructureDecode(
+  const u8 *pData,                /* Buffer containing serialized structure */
+  int nData,                      /* Size of buffer pData in bytes */
+  int *piCookie,                  /* Configuration cookie value */
+  Fts5Structure **ppOut           /* OUT: Deserialized object */
+){
+  int rc = SQLITE_OK;
+  int i = 0;
+  int iLvl;
+  int nLevel = 0;
+  int nSegment = 0;
+  sqlite3_int64 nByte;            /* Bytes of space to allocate at pRet */
+  Fts5Structure *pRet = 0;        /* Structure object to return */
+  int bStructureV2 = 0;           /* True for FTS5_STRUCTURE_V2 */
+  u64 nOriginCntr = 0;            /* Largest origin value seen so far */
+
+  /* Grab the cookie value */
+  if( piCookie ) *piCookie = sqlite3Fts5Get32(pData);
+  i = 4;
+
+  /* Check if this is a V2 structure record. Set bStructureV2 if it is. */
+  if( 0==memcmp(&pData[i], FTS5_STRUCTURE_V2, 4) ){
+    i += 4;
+    bStructureV2 = 1;
+  }
+
+  /* Read the total number of levels and segments from the start of the
+  ** structure record.  */
+  i += fts5GetVarint32(&pData[i], nLevel);
+  i += fts5GetVarint32(&pData[i], nSegment);
+  if( nLevel>FTS5_MAX_SEGMENT   || nLevel<0
+   || nSegment>FTS5_MAX_SEGMENT || nSegment<0
+  ){
+    return FTS5_CORRUPT;
+  }
+  nByte = (
+      sizeof(Fts5Structure) +                    /* Main structure */
+      sizeof(Fts5StructureLevel) * (nLevel-1)    /* aLevel[] array */
+  );
+  pRet = (Fts5Structure*)sqlite3Fts5MallocZero(&rc, nByte);
+
+  if( pRet ){
+    pRet->nRef = 1;
+    pRet->nLevel = nLevel;
+    pRet->nSegment = nSegment;
+    i += sqlite3Fts5GetVarint(&pData[i], &pRet->nWriteCounter);
+
+    for(iLvl=0; rc==SQLITE_OK && iLvl<nLevel; iLvl++){
+      Fts5StructureLevel *pLvl = &pRet->aLevel[iLvl];
+      int nTotal = 0;
+      int iSeg;
+
+      if( i>=nData ){
+        rc = FTS5_CORRUPT;
+      }else{
+        i += fts5GetVarint32(&pData[i], pLvl->nMerge);
+        i += fts5GetVarint32(&pData[i], nTotal);
+        if( nTotal<pLvl->nMerge ) rc = FTS5_CORRUPT;
+        pLvl->aSeg = (Fts5StructureSegment*)sqlite3Fts5MallocZero(&rc,
+            nTotal * sizeof(Fts5StructureSegment)
+        );
+        nSegment -= nTotal;
+      }
+
+      if( rc==SQLITE_OK ){
+        pLvl->nSeg = nTotal;
+        for(iSeg=0; iSeg<nTotal; iSeg++){
+          Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
+          if( i>=nData ){
+            rc = FTS5_CORRUPT;
+            break;
+          }
+          assert( pSeg!=0 );
+          i += fts5GetVarint32(&pData[i], pSeg->iSegid);
+          i += fts5GetVarint32(&pData[i], pSeg->pgnoFirst);
+          i += fts5GetVarint32(&pData[i], pSeg->pgnoLast);
+          if( bStructureV2 ){
+            i += fts5GetVarint(&pData[i], &pSeg->iOrigin1);
+            i += fts5GetVarint(&pData[i], &pSeg->iOrigin2);
+            i += fts5GetVarint32(&pData[i], pSeg->nPgTombstone);
+            i += fts5GetVarint(&pData[i], &pSeg->nEntryTombstone);
+            i += fts5GetVarint(&pData[i], &pSeg->nEntry);
+            nOriginCntr = MAX(nOriginCntr, pSeg->iOrigin2);
+          }
+          if( pSeg->pgnoLast<pSeg->pgnoFirst ){
+            rc = FTS5_CORRUPT;
+            break;
+          }
+        }
+        if( iLvl>0 && pLvl[-1].nMerge && nTotal==0 ) rc = FTS5_CORRUPT;
+        if( iLvl==nLevel-1 && pLvl->nMerge ) rc = FTS5_CORRUPT;
+      }
+    }
+    if( nSegment!=0 && rc==SQLITE_OK ) rc = FTS5_CORRUPT;
+    if( bStructureV2 ){
+      pRet->nOriginCntr = nOriginCntr+1;
+    }
+
+    if( rc!=SQLITE_OK ){
+      fts5StructureRelease(pRet);
+      pRet = 0;
+    }
+  }
+
+  *ppOut = pRet;
+  return rc;
+}
+
+/*
+** Add a level to the Fts5Structure.aLevel[] array of structure object
+** (*ppStruct).
+*/
+static void fts5StructureAddLevel(int *pRc, Fts5Structure **ppStruct){
+  fts5StructureMakeWritable(pRc, ppStruct);
+  assert( (ppStruct!=0 && (*ppStruct)!=0) || (*pRc)!=SQLITE_OK );
+  if( *pRc==SQLITE_OK ){
+    Fts5Structure *pStruct = *ppStruct;
+    int nLevel = pStruct->nLevel;
+    sqlite3_int64 nByte = (
+        sizeof(Fts5Structure) +                  /* Main structure */
+        sizeof(Fts5StructureLevel) * (nLevel+1)  /* aLevel[] array */
+    );
+
+    pStruct = sqlite3_realloc64(pStruct, nByte);
+    if( pStruct ){
+      memset(&pStruct->aLevel[nLevel], 0, sizeof(Fts5StructureLevel));
+      pStruct->nLevel++;
+      *ppStruct = pStruct;
+    }else{
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+}
+
+/*
+** Extend level iLvl so that there is room for at least nExtra more
+** segments.
+*/
+static void fts5StructureExtendLevel(
+  int *pRc,
+  Fts5Structure *pStruct,
+  int iLvl,
+  int nExtra,
+  int bInsert
+){
+  if( *pRc==SQLITE_OK ){
+    Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
+    Fts5StructureSegment *aNew;
+    sqlite3_int64 nByte;
+
+    nByte = (pLvl->nSeg + nExtra) * sizeof(Fts5StructureSegment);
+    aNew = sqlite3_realloc64(pLvl->aSeg, nByte);
+    if( aNew ){
+      if( bInsert==0 ){
+        memset(&aNew[pLvl->nSeg], 0, sizeof(Fts5StructureSegment) * nExtra);
+      }else{
+        int nMove = pLvl->nSeg * sizeof(Fts5StructureSegment);
+        memmove(&aNew[nExtra], aNew, nMove);
+        memset(aNew, 0, sizeof(Fts5StructureSegment) * nExtra);
+      }
+      pLvl->aSeg = aNew;
+    }else{
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+}
+
+static Fts5Structure *fts5StructureReadUncached(Fts5Index *p){
+  Fts5Structure *pRet = 0;
+  Fts5Config *pConfig = p->pConfig;
+  int iCookie;                    /* Configuration cookie */
+  Fts5Data *pData;
+
+  pData = fts5DataRead(p, FTS5_STRUCTURE_ROWID);
+  if( p->rc==SQLITE_OK ){
+    /* TODO: Do we need this if the leaf-index is appended? Probably... */
+    memset(&pData->p[pData->nn], 0, FTS5_DATA_PADDING);
+    p->rc = fts5StructureDecode(pData->p, pData->nn, &iCookie, &pRet);
+    if( p->rc==SQLITE_OK && (pConfig->pgsz==0 || pConfig->iCookie!=iCookie) ){
+      p->rc = sqlite3Fts5ConfigLoad(pConfig, iCookie);
+    }
+    fts5DataRelease(pData);
+    if( p->rc!=SQLITE_OK ){
+      fts5StructureRelease(pRet);
+      pRet = 0;
+    }
+  }
+
+  return pRet;
+}
+
+static i64 fts5IndexDataVersion(Fts5Index *p){
+  i64 iVersion = 0;
+
+  if( p->rc==SQLITE_OK ){
+    if( p->pDataVersion==0 ){
+      p->rc = fts5IndexPrepareStmt(p, &p->pDataVersion,
+          sqlite3_mprintf("PRAGMA %Q.data_version", p->pConfig->zDb)
+          );
+      if( p->rc ) return 0;
+    }
+
+    if( SQLITE_ROW==sqlite3_step(p->pDataVersion) ){
+      iVersion = sqlite3_column_int64(p->pDataVersion, 0);
+    }
+    p->rc = sqlite3_reset(p->pDataVersion);
+  }
+
+  return iVersion;
+}
+
+/*
+** Read, deserialize and return the structure record.
+**
+** The Fts5Structure.aLevel[] and each Fts5StructureLevel.aSeg[] array
+** are over-allocated as described for function fts5StructureDecode()
+** above.
+**
+** If an error occurs, NULL is returned and an error code left in the
+** Fts5Index handle. If an error has already occurred when this function
+** is called, it is a no-op.
+*/
+static Fts5Structure *fts5StructureRead(Fts5Index *p){
+
+  if( p->pStruct==0 ){
+    p->iStructVersion = fts5IndexDataVersion(p);
+    if( p->rc==SQLITE_OK ){
+      p->pStruct = fts5StructureReadUncached(p);
+    }
+  }
+
+#if 0
+  else{
+    Fts5Structure *pTest = fts5StructureReadUncached(p);
+    if( pTest ){
+      int i, j;
+      assert_nc( p->pStruct->nSegment==pTest->nSegment );
+      assert_nc( p->pStruct->nLevel==pTest->nLevel );
+      for(i=0; i<pTest->nLevel; i++){
+        assert_nc( p->pStruct->aLevel[i].nMerge==pTest->aLevel[i].nMerge );
+        assert_nc( p->pStruct->aLevel[i].nSeg==pTest->aLevel[i].nSeg );
+        for(j=0; j<pTest->aLevel[i].nSeg; j++){
+          Fts5StructureSegment *p1 = &pTest->aLevel[i].aSeg[j];
+          Fts5StructureSegment *p2 = &p->pStruct->aLevel[i].aSeg[j];
+          assert_nc( p1->iSegid==p2->iSegid );
+          assert_nc( p1->pgnoFirst==p2->pgnoFirst );
+          assert_nc( p1->pgnoLast==p2->pgnoLast );
+        }
+      }
+      fts5StructureRelease(pTest);
+    }
+  }
+#endif
+
+  if( p->rc!=SQLITE_OK ) return 0;
+  assert( p->iStructVersion!=0 );
+  assert( p->pStruct!=0 );
+  fts5StructureRef(p->pStruct);
+  return p->pStruct;
+}
+
+static void fts5StructureInvalidate(Fts5Index *p){
+  if( p->pStruct ){
+    fts5StructureRelease(p->pStruct);
+    p->pStruct = 0;
+  }
+}
+
+/*
+** Return the total number of segments in index structure pStruct. This
+** function is only ever used as part of assert() conditions.
+*/
+#ifdef SQLITE_DEBUG
+static int fts5StructureCountSegments(Fts5Structure *pStruct){
+  int nSegment = 0;               /* Total number of segments */
+  if( pStruct ){
+    int iLvl;                     /* Used to iterate through levels */
+    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+      nSegment += pStruct->aLevel[iLvl].nSeg;
+    }
+  }
+
+  return nSegment;
+}
+#endif
+
+#define fts5BufferSafeAppendBlob(pBuf, pBlob, nBlob) {     \
+  assert( (pBuf)->nSpace>=((pBuf)->n+nBlob) );             \
+  memcpy(&(pBuf)->p[(pBuf)->n], pBlob, nBlob);             \
+  (pBuf)->n += nBlob;                                      \
+}
+
+#define fts5BufferSafeAppendVarint(pBuf, iVal) {                \
+  (pBuf)->n += sqlite3Fts5PutVarint(&(pBuf)->p[(pBuf)->n], (iVal));  \
+  assert( (pBuf)->nSpace>=(pBuf)->n );                          \
+}
+
+
+/*
+** Serialize and store the "structure" record.
+**
+** If an error occurs, leave an error code in the Fts5Index object. If an
+** error has already occurred, this function is a no-op.
+*/
+static void fts5StructureWrite(Fts5Index *p, Fts5Structure *pStruct){
+  if( p->rc==SQLITE_OK ){
+    Fts5Buffer buf;               /* Buffer to serialize record into */
+    int iLvl;                     /* Used to iterate through levels */
+    int iCookie;                  /* Cookie value to store */
+    int nHdr = (pStruct->nOriginCntr>0 ? (4+4+9+9+9) : (4+9+9));
+
+    assert( pStruct->nSegment==fts5StructureCountSegments(pStruct) );
+    memset(&buf, 0, sizeof(Fts5Buffer));
+
+    /* Append the current configuration cookie */
+    iCookie = p->pConfig->iCookie;
+    if( iCookie<0 ) iCookie = 0;
+
+    if( 0==sqlite3Fts5BufferSize(&p->rc, &buf, nHdr) ){
+      sqlite3Fts5Put32(buf.p, iCookie);
+      buf.n = 4;
+      if( pStruct->nOriginCntr>0 ){
+        fts5BufferSafeAppendBlob(&buf, FTS5_STRUCTURE_V2, 4);
+      }
+      fts5BufferSafeAppendVarint(&buf, pStruct->nLevel);
+      fts5BufferSafeAppendVarint(&buf, pStruct->nSegment);
+      fts5BufferSafeAppendVarint(&buf, (i64)pStruct->nWriteCounter);
+    }
+
+    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+      int iSeg;                     /* Used to iterate through segments */
+      Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
+      fts5BufferAppendVarint(&p->rc, &buf, pLvl->nMerge);
+      fts5BufferAppendVarint(&p->rc, &buf, pLvl->nSeg);
+      assert( pLvl->nMerge<=pLvl->nSeg );
+
+      for(iSeg=0; iSeg<pLvl->nSeg; iSeg++){
+        Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
+        fts5BufferAppendVarint(&p->rc, &buf, pSeg->iSegid);
+        fts5BufferAppendVarint(&p->rc, &buf, pSeg->pgnoFirst);
+        fts5BufferAppendVarint(&p->rc, &buf, pSeg->pgnoLast);
+        if( pStruct->nOriginCntr>0 ){
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->iOrigin1);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->iOrigin2);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->nPgTombstone);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->nEntryTombstone);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->nEntry);
+        }
+      }
+    }
+
+    fts5DataWrite(p, FTS5_STRUCTURE_ROWID, buf.p, buf.n);
+    fts5BufferFree(&buf);
+  }
+}
+
+#if 0
+static void fts5DebugStructure(int*,Fts5Buffer*,Fts5Structure*);
+static void fts5PrintStructure(const char *zCaption, Fts5Structure *pStruct){
+  int rc = SQLITE_OK;
+  Fts5Buffer buf;
+  memset(&buf, 0, sizeof(buf));
+  fts5DebugStructure(&rc, &buf, pStruct);
+  fprintf(stdout, "%s: %s\n", zCaption, buf.p);
+  fflush(stdout);
+  fts5BufferFree(&buf);
+}
+#else
+# define fts5PrintStructure(x,y)
+#endif
+
+static int fts5SegmentSize(Fts5StructureSegment *pSeg){
+  return 1 + pSeg->pgnoLast - pSeg->pgnoFirst;
+}
+
+/*
+** Return a copy of index structure pStruct. Except, promote as many
+** segments as possible to level iPromote. If an OOM occurs, NULL is
+** returned.
+*/
+static void fts5StructurePromoteTo(
+  Fts5Index *p,
+  int iPromote,
+  int szPromote,
+  Fts5Structure *pStruct
+){
+  int il, is;
+  Fts5StructureLevel *pOut = &pStruct->aLevel[iPromote];
+
+  if( pOut->nMerge==0 ){
+    for(il=iPromote+1; il<pStruct->nLevel; il++){
+      Fts5StructureLevel *pLvl = &pStruct->aLevel[il];
+      if( pLvl->nMerge ) return;
+      for(is=pLvl->nSeg-1; is>=0; is--){
+        int sz = fts5SegmentSize(&pLvl->aSeg[is]);
+        if( sz>szPromote ) return;
+        fts5StructureExtendLevel(&p->rc, pStruct, iPromote, 1, 1);
+        if( p->rc ) return;
+        memcpy(pOut->aSeg, &pLvl->aSeg[is], sizeof(Fts5StructureSegment));
+        pOut->nSeg++;
+        pLvl->nSeg--;
+      }
+    }
+  }
+}
+
+/*
+** A new segment has just been written to level iLvl of index structure
+** pStruct. This function determines if any segments should be promoted
+** as a result. Segments are promoted in two scenarios:
+**
+**   a) If the segment just written is smaller than one or more segments
+**      within the previous populated level, it is promoted to the previous
+**      populated level.
+**
+**   b) If the segment just written is larger than the newest segment on
+**      the next populated level, then that segment, and any other adjacent
+**      segments that are also smaller than the one just written, are
+**      promoted.
+**
+** If one or more segments are promoted, the structure object is updated
+** to reflect this.
+*/
+static void fts5StructurePromote(
+  Fts5Index *p,                   /* FTS5 backend object */
+  int iLvl,                       /* Index level just updated */
+  Fts5Structure *pStruct          /* Index structure */
+){
+  if( p->rc==SQLITE_OK ){
+    int iTst;
+    int iPromote = -1;
+    int szPromote = 0;            /* Promote anything this size or smaller */
+    Fts5StructureSegment *pSeg;   /* Segment just written */
+    int szSeg;                    /* Size of segment just written */
+    int nSeg = pStruct->aLevel[iLvl].nSeg;
+
+    if( nSeg==0 ) return;
+    pSeg = &pStruct->aLevel[iLvl].aSeg[pStruct->aLevel[iLvl].nSeg-1];
+    szSeg = (1 + pSeg->pgnoLast - pSeg->pgnoFirst);
+
+    /* Check for condition (a) */
+    for(iTst=iLvl-1; iTst>=0 && pStruct->aLevel[iTst].nSeg==0; iTst--);
+    if( iTst>=0 ){
+      int i;
+      int szMax = 0;
+      Fts5StructureLevel *pTst = &pStruct->aLevel[iTst];
+      assert( pTst->nMerge==0 );
+      for(i=0; i<pTst->nSeg; i++){
+        int sz = pTst->aSeg[i].pgnoLast - pTst->aSeg[i].pgnoFirst + 1;
+        if( sz>szMax ) szMax = sz;
+      }
+      if( szMax>=szSeg ){
+        /* Condition (a) is true. Promote the newest segment on level
+        ** iLvl to level iTst.  */
+        iPromote = iTst;
+        szPromote = szMax;
+      }
+    }
+
+    /* If condition (a) is not met, assume (b) is true. StructurePromoteTo()
+    ** is a no-op if it is not.  */
+    if( iPromote<0 ){
+      iPromote = iLvl;
+      szPromote = szSeg;
+    }
+    fts5StructurePromoteTo(p, iPromote, szPromote, pStruct);
+  }
+}
+
+
+/*
+** Advance the iterator passed as the only argument. If the end of the
+** doclist-index page is reached, return non-zero.
+*/
+static int fts5DlidxLvlNext(Fts5DlidxLvl *pLvl){
+  Fts5Data *pData = pLvl->pData;
+
+  if( pLvl->iOff==0 ){
+    assert( pLvl->bEof==0 );
+    pLvl->iOff = 1;
+    pLvl->iOff += fts5GetVarint32(&pData->p[1], pLvl->iLeafPgno);
+    pLvl->iOff += fts5GetVarint(&pData->p[pLvl->iOff], (u64*)&pLvl->iRowid);
+    pLvl->iFirstOff = pLvl->iOff;
+  }else{
+    int iOff;
+    for(iOff=pLvl->iOff; iOff<pData->nn; iOff++){
+      if( pData->p[iOff] ) break;
+    }
+
+    if( iOff<pData->nn ){
+      u64 iVal;
+      pLvl->iLeafPgno += (iOff - pLvl->iOff) + 1;
+      iOff += fts5GetVarint(&pData->p[iOff], &iVal);
+      pLvl->iRowid += iVal;
+      pLvl->iOff = iOff;
+    }else{
+      pLvl->bEof = 1;
+    }
+  }
+
+  return pLvl->bEof;
+}
+
+/*
+** Advance the iterator passed as the only argument.
+*/
+static int fts5DlidxIterNextR(Fts5Index *p, Fts5DlidxIter *pIter, int iLvl){
+  Fts5DlidxLvl *pLvl = &pIter->aLvl[iLvl];
+
+  assert( iLvl<pIter->nLvl );
+  if( fts5DlidxLvlNext(pLvl) ){
+    if( (iLvl+1) < pIter->nLvl ){
+      fts5DlidxIterNextR(p, pIter, iLvl+1);
+      if( pLvl[1].bEof==0 ){
+        fts5DataRelease(pLvl->pData);
+        memset(pLvl, 0, sizeof(Fts5DlidxLvl));
+        pLvl->pData = fts5DataRead(p,
+            FTS5_DLIDX_ROWID(pIter->iSegid, iLvl, pLvl[1].iLeafPgno)
+        );
+        if( pLvl->pData ) fts5DlidxLvlNext(pLvl);
+      }
+    }
+  }
+
+  return pIter->aLvl[0].bEof;
+}
+static int fts5DlidxIterNext(Fts5Index *p, Fts5DlidxIter *pIter){
+  return fts5DlidxIterNextR(p, pIter, 0);
+}
+
+/*
+** The iterator passed as the first argument has the following fields set
+** as follows. This function sets up the rest of the iterator so that it
+** points to the first rowid in the doclist-index.
+**
+**   pData:
+**     pointer to doclist-index record,
+**
+** When this function is called pIter->iLeafPgno is the page number the
+** doclist is associated with (the one featuring the term).
+*/
+static int fts5DlidxIterFirst(Fts5DlidxIter *pIter){
+  int i;
+  for(i=0; i<pIter->nLvl; i++){
+    fts5DlidxLvlNext(&pIter->aLvl[i]);
+  }
+  return pIter->aLvl[0].bEof;
+}
+
+
+static int fts5DlidxIterEof(Fts5Index *p, Fts5DlidxIter *pIter){
+  return p->rc!=SQLITE_OK || pIter->aLvl[0].bEof;
+}
+
+static void fts5DlidxIterLast(Fts5Index *p, Fts5DlidxIter *pIter){
+  int i;
+
+  /* Advance each level to the last entry on the last page */
+  for(i=pIter->nLvl-1; p->rc==SQLITE_OK && i>=0; i--){
+    Fts5DlidxLvl *pLvl = &pIter->aLvl[i];
+    while( fts5DlidxLvlNext(pLvl)==0 );
+    pLvl->bEof = 0;
+
+    if( i>0 ){
+      Fts5DlidxLvl *pChild = &pLvl[-1];
+      fts5DataRelease(pChild->pData);
+      memset(pChild, 0, sizeof(Fts5DlidxLvl));
+      pChild->pData = fts5DataRead(p,
+          FTS5_DLIDX_ROWID(pIter->iSegid, i-1, pLvl->iLeafPgno)
+      );
+    }
+  }
+}
+
+/*
+** Move the iterator passed as the only argument to the previous entry.
+*/
+static int fts5DlidxLvlPrev(Fts5DlidxLvl *pLvl){
+  int iOff = pLvl->iOff;
+
+  assert( pLvl->bEof==0 );
+  if( iOff<=pLvl->iFirstOff ){
+    pLvl->bEof = 1;
+  }else{
+    u8 *a = pLvl->pData->p;
+
+    pLvl->iOff = 0;
+    fts5DlidxLvlNext(pLvl);
+    while( 1 ){
+      int nZero = 0;
+      int ii = pLvl->iOff;
+      u64 delta = 0;
+
+      while( a[ii]==0 ){
+        nZero++;
+        ii++;
+      }
+      ii += sqlite3Fts5GetVarint(&a[ii], &delta);
+
+      if( ii>=iOff ) break;
+      pLvl->iLeafPgno += nZero+1;
+      pLvl->iRowid += delta;
+      pLvl->iOff = ii;
+    }
+  }
+
+  return pLvl->bEof;
+}
+
+static int fts5DlidxIterPrevR(Fts5Index *p, Fts5DlidxIter *pIter, int iLvl){
+  Fts5DlidxLvl *pLvl = &pIter->aLvl[iLvl];
+
+  assert( iLvl<pIter->nLvl );
+  if( fts5DlidxLvlPrev(pLvl) ){
+    if( (iLvl+1) < pIter->nLvl ){
+      fts5DlidxIterPrevR(p, pIter, iLvl+1);
+      if( pLvl[1].bEof==0 ){
+        fts5DataRelease(pLvl->pData);
+        memset(pLvl, 0, sizeof(Fts5DlidxLvl));
+        pLvl->pData = fts5DataRead(p,
+            FTS5_DLIDX_ROWID(pIter->iSegid, iLvl, pLvl[1].iLeafPgno)
+        );
+        if( pLvl->pData ){
+          while( fts5DlidxLvlNext(pLvl)==0 );
+          pLvl->bEof = 0;
+        }
+      }
+    }
+  }
+
+  return pIter->aLvl[0].bEof;
+}
+static int fts5DlidxIterPrev(Fts5Index *p, Fts5DlidxIter *pIter){
+  return fts5DlidxIterPrevR(p, pIter, 0);
+}
+
+/*
+** Free a doclist-index iterator object allocated by fts5DlidxIterInit().
+*/
+static void fts5DlidxIterFree(Fts5DlidxIter *pIter){
+  if( pIter ){
+    int i;
+    for(i=0; i<pIter->nLvl; i++){
+      fts5DataRelease(pIter->aLvl[i].pData);
+    }
+    sqlite3_free(pIter);
+  }
+}
+
+static Fts5DlidxIter *fts5DlidxIterInit(
+  Fts5Index *p,                   /* Fts5 Backend to iterate within */
+  int bRev,                       /* True for ORDER BY ASC */
+  int iSegid,                     /* Segment id */
+  int iLeafPg                     /* Leaf page number to load dlidx for */
+){
+  Fts5DlidxIter *pIter = 0;
+  int i;
+  int bDone = 0;
+
+  for(i=0; p->rc==SQLITE_OK && bDone==0; i++){
+    sqlite3_int64 nByte = sizeof(Fts5DlidxIter) + i * sizeof(Fts5DlidxLvl);
+    Fts5DlidxIter *pNew;
+
+    pNew = (Fts5DlidxIter*)sqlite3_realloc64(pIter, nByte);
+    if( pNew==0 ){
+      p->rc = SQLITE_NOMEM;
+    }else{
+      i64 iRowid = FTS5_DLIDX_ROWID(iSegid, i, iLeafPg);
+      Fts5DlidxLvl *pLvl = &pNew->aLvl[i];
+      pIter = pNew;
+      memset(pLvl, 0, sizeof(Fts5DlidxLvl));
+      pLvl->pData = fts5DataRead(p, iRowid);
+      if( pLvl->pData && (pLvl->pData->p[0] & 0x0001)==0 ){
+        bDone = 1;
+      }
+      pIter->nLvl = i+1;
+    }
+  }
+
+  if( p->rc==SQLITE_OK ){
+    pIter->iSegid = iSegid;
+    if( bRev==0 ){
+      fts5DlidxIterFirst(pIter);
+    }else{
+      fts5DlidxIterLast(p, pIter);
+    }
+  }
+
+  if( p->rc!=SQLITE_OK ){
+    fts5DlidxIterFree(pIter);
+    pIter = 0;
+  }
+
+  return pIter;
+}
+
+static i64 fts5DlidxIterRowid(Fts5DlidxIter *pIter){
+  return pIter->aLvl[0].iRowid;
+}
+static int fts5DlidxIterPgno(Fts5DlidxIter *pIter){
+  return pIter->aLvl[0].iLeafPgno;
+}
+
+/*
+** Load the next leaf page into the segment iterator.
+*/
+static void fts5SegIterNextPage(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter              /* Iterator to advance to next page */
+){
+  Fts5Data *pLeaf;
+  Fts5StructureSegment *pSeg = pIter->pSeg;
+  fts5DataRelease(pIter->pLeaf);
+  pIter->iLeafPgno++;
+  if( pIter->pNextLeaf ){
+    pIter->pLeaf = pIter->pNextLeaf;
+    pIter->pNextLeaf = 0;
+  }else if( pIter->iLeafPgno<=pSeg->pgnoLast ){
+    pIter->pLeaf = fts5LeafRead(p,
+        FTS5_SEGMENT_ROWID(pSeg->iSegid, pIter->iLeafPgno)
+    );
+  }else{
+    pIter->pLeaf = 0;
+  }
+  pLeaf = pIter->pLeaf;
+
+  if( pLeaf ){
+    pIter->iPgidxOff = pLeaf->szLeaf;
+    if( fts5LeafIsTermless(pLeaf) ){
+      pIter->iEndofDoclist = pLeaf->nn+1;
+    }else{
+      pIter->iPgidxOff += fts5GetVarint32(&pLeaf->p[pIter->iPgidxOff],
+          pIter->iEndofDoclist
+      );
+    }
+  }
+}
+
+/*
+** Argument p points to a buffer containing a varint to be interpreted as a
+** position list size field. Read the varint and return the number of bytes
+** read. Before returning, set *pnSz to the number of bytes in the position
+** list, and *pbDel to true if the delete flag is set, or false otherwise.
+*/
+static int fts5GetPoslistSize(const u8 *p, int *pnSz, int *pbDel){
+  int nSz;
+  int n = 0;
+  fts5FastGetVarint32(p, n, nSz);
+  assert_nc( nSz>=0 );
+  *pnSz = nSz/2;
+  *pbDel = nSz & 0x0001;
+  return n;
+}
+
+/*
+** Fts5SegIter.iLeafOffset currently points to the first byte of a
+** position-list size field. Read the value of the field and store it
+** in the following variables:
+**
+**   Fts5SegIter.nPos
+**   Fts5SegIter.bDel
+**
+** Leave Fts5SegIter.iLeafOffset pointing to the first byte of the
+** position list content (if any).
+*/
+static void fts5SegIterLoadNPos(Fts5Index *p, Fts5SegIter *pIter){
+  if( p->rc==SQLITE_OK ){
+    int iOff = pIter->iLeafOffset;  /* Offset to read at */
+    ASSERT_SZLEAF_OK(pIter->pLeaf);
+    if( p->pConfig->eDetail==FTS5_DETAIL_NONE ){
+      int iEod = MIN(pIter->iEndofDoclist, pIter->pLeaf->szLeaf);
+      pIter->bDel = 0;
+      pIter->nPos = 1;
+      if( iOff<iEod && pIter->pLeaf->p[iOff]==0 ){
+        pIter->bDel = 1;
+        iOff++;
+        if( iOff<iEod && pIter->pLeaf->p[iOff]==0 ){
+          pIter->nPos = 1;
+          iOff++;
+        }else{
+          pIter->nPos = 0;
+        }
+      }
+    }else{
+      int nSz;
+      fts5FastGetVarint32(pIter->pLeaf->p, iOff, nSz);
+      pIter->bDel = (nSz & 0x0001);
+      pIter->nPos = nSz>>1;
+      assert_nc( pIter->nPos>=0 );
+    }
+    pIter->iLeafOffset = iOff;
+  }
+}
+
+static void fts5SegIterLoadRowid(Fts5Index *p, Fts5SegIter *pIter){
+  u8 *a = pIter->pLeaf->p;        /* Buffer to read data from */
+  i64 iOff = pIter->iLeafOffset;
+
+  ASSERT_SZLEAF_OK(pIter->pLeaf);
+  while( iOff>=pIter->pLeaf->szLeaf ){
+    fts5SegIterNextPage(p, pIter);
+    if( pIter->pLeaf==0 ){
+      if( p->rc==SQLITE_OK ) p->rc = FTS5_CORRUPT;
+      return;
+    }
+    iOff = 4;
+    a = pIter->pLeaf->p;
+  }
+  iOff += sqlite3Fts5GetVarint(&a[iOff], (u64*)&pIter->iRowid);
+  pIter->iLeafOffset = iOff;
+}
+
+/*
+** Fts5SegIter.iLeafOffset currently points to the first byte of the
+** "nSuffix" field of a term. Function parameter nKeep contains the value
+** of the "nPrefix" field (if there was one - it is passed 0 if this is
+** the first term in the segment).
+**
+** This function populates:
+**
+**   Fts5SegIter.term
+**   Fts5SegIter.rowid
+**
+** accordingly and leaves (Fts5SegIter.iLeafOffset) set to the content of
+** the first position list. The position list belonging to document
+** (Fts5SegIter.iRowid).
+*/
+static void fts5SegIterLoadTerm(Fts5Index *p, Fts5SegIter *pIter, int nKeep){
+  u8 *a = pIter->pLeaf->p;        /* Buffer to read data from */
+  i64 iOff = pIter->iLeafOffset;  /* Offset to read at */
+  int nNew;                       /* Bytes of new data */
+
+  iOff += fts5GetVarint32(&a[iOff], nNew);
+  if( iOff+nNew>pIter->pLeaf->szLeaf || nKeep>pIter->term.n || nNew==0 ){
+    p->rc = FTS5_CORRUPT;
+    return;
+  }
+  pIter->term.n = nKeep;
+  fts5BufferAppendBlob(&p->rc, &pIter->term, nNew, &a[iOff]);
+  assert( pIter->term.n<=pIter->term.nSpace );
+  iOff += nNew;
+  pIter->iTermLeafOffset = iOff;
+  pIter->iTermLeafPgno = pIter->iLeafPgno;
+  pIter->iLeafOffset = iOff;
+
+  if( pIter->iPgidxOff>=pIter->pLeaf->nn ){
+    pIter->iEndofDoclist = pIter->pLeaf->nn+1;
+  }else{
+    int nExtra;
+    pIter->iPgidxOff += fts5GetVarint32(&a[pIter->iPgidxOff], nExtra);
+    pIter->iEndofDoclist += nExtra;
+  }
+
+  fts5SegIterLoadRowid(p, pIter);
+}
+
+static void fts5SegIterNext(Fts5Index*, Fts5SegIter*, int*);
+static void fts5SegIterNext_Reverse(Fts5Index*, Fts5SegIter*, int*);
+static void fts5SegIterNext_None(Fts5Index*, Fts5SegIter*, int*);
+
+static void fts5SegIterSetNext(Fts5Index *p, Fts5SegIter *pIter){
+  if( pIter->flags & FTS5_SEGITER_REVERSE ){
+    pIter->xNext = fts5SegIterNext_Reverse;
+  }else if( p->pConfig->eDetail==FTS5_DETAIL_NONE ){
+    pIter->xNext = fts5SegIterNext_None;
+  }else{
+    pIter->xNext = fts5SegIterNext;
+  }
+}
+
+/*
+** Allocate a tombstone hash page array object (pIter->pTombArray) for
+** the iterator passed as the second argument. If an OOM error occurs,
+** leave an error in the Fts5Index object.
+*/
+static void fts5SegIterAllocTombstone(Fts5Index *p, Fts5SegIter *pIter){
+  const int nTomb = pIter->pSeg->nPgTombstone;
+  if( nTomb>0 ){
+    int nByte = nTomb * sizeof(Fts5Data*) + sizeof(Fts5TombstoneArray);
+    Fts5TombstoneArray *pNew;
+    pNew = (Fts5TombstoneArray*)sqlite3Fts5MallocZero(&p->rc, nByte);
+    if( pNew ){
+      pNew->nTombstone = nTomb;
+      pNew->nRef = 1;
+      pIter->pTombArray = pNew;
+    }
+  }
+}
+
+/*
+** Initialize the iterator object pIter to iterate through the entries in
+** segment pSeg. The iterator is left pointing to the first entry when
+** this function returns.
+**
+** If an error occurs, Fts5Index.rc is set to an appropriate error code. If
+** an error has already occurred when this function is called, it is a no-op.
+*/
+static void fts5SegIterInit(
+  Fts5Index *p,                   /* FTS index object */
+  Fts5StructureSegment *pSeg,     /* Description of segment */
+  Fts5SegIter *pIter              /* Object to populate */
+){
+  if( pSeg->pgnoFirst==0 ){
+    /* This happens if the segment is being used as an input to an incremental
+    ** merge and all data has already been "trimmed". See function
+    ** fts5TrimSegments() for details. In this case leave the iterator empty.
+    ** The caller will see the (pIter->pLeaf==0) and assume the iterator is
+    ** at EOF already. */
+    assert( pIter->pLeaf==0 );
+    return;
+  }
+
+  if( p->rc==SQLITE_OK ){
+    memset(pIter, 0, sizeof(*pIter));
+    fts5SegIterSetNext(p, pIter);
+    pIter->pSeg = pSeg;
+    pIter->iLeafPgno = pSeg->pgnoFirst-1;
+    do {
+      fts5SegIterNextPage(p, pIter);
+    }while( p->rc==SQLITE_OK && pIter->pLeaf && pIter->pLeaf->nn==4 );
+  }
+
+  if( p->rc==SQLITE_OK && pIter->pLeaf ){
+    pIter->iLeafOffset = 4;
+    assert( pIter->pLeaf!=0 );
+    assert_nc( pIter->pLeaf->nn>4 );
+    assert_nc( fts5LeafFirstTermOff(pIter->pLeaf)==4 );
+    pIter->iPgidxOff = pIter->pLeaf->szLeaf+1;
+    fts5SegIterLoadTerm(p, pIter, 0);
+    fts5SegIterLoadNPos(p, pIter);
+    fts5SegIterAllocTombstone(p, pIter);
+  }
+}
+
+/*
+** This function is only ever called on iterators created by calls to
+** Fts5IndexQuery() with the FTS5INDEX_QUERY_DESC flag set.
+**
+** The iterator is in an unusual state when this function is called: the
+** Fts5SegIter.iLeafOffset variable is set to the offset of the start of
+** the position-list size field for the first relevant rowid on the page.
+** Fts5SegIter.rowid is set, but nPos and bDel are not.
+**
+** This function advances the iterator so that it points to the last
+** relevant rowid on the page and, if necessary, initializes the
+** aRowidOffset[] and iRowidOffset variables. At this point the iterator
+** is in its regular state - Fts5SegIter.iLeafOffset points to the first
+** byte of the position list content associated with said rowid.
+*/
+static void fts5SegIterReverseInitPage(Fts5Index *p, Fts5SegIter *pIter){
+  int eDetail = p->pConfig->eDetail;
+  int n = pIter->pLeaf->szLeaf;
+  int i = pIter->iLeafOffset;
+  u8 *a = pIter->pLeaf->p;
+  int iRowidOffset = 0;
+
+  if( n>pIter->iEndofDoclist ){
+    n = pIter->iEndofDoclist;
+  }
+
+  ASSERT_SZLEAF_OK(pIter->pLeaf);
+  while( 1 ){
+    u64 iDelta = 0;
+
+    if( eDetail==FTS5_DETAIL_NONE ){
+      /* todo */
+      if( i<n && a[i]==0 ){
+        i++;
+        if( i<n && a[i]==0 ) i++;
+      }
+    }else{
+      int nPos;
+      int bDummy;
+      i += fts5GetPoslistSize(&a[i], &nPos, &bDummy);
+      i += nPos;
+    }
+    if( i>=n ) break;
+    i += fts5GetVarint(&a[i], &iDelta);
+    pIter->iRowid += iDelta;
+
+    /* If necessary, grow the pIter->aRowidOffset[] array. */
+    if( iRowidOffset>=pIter->nRowidOffset ){
+      int nNew = pIter->nRowidOffset + 8;
+      int *aNew = (int*)sqlite3_realloc64(pIter->aRowidOffset,nNew*sizeof(int));
+      if( aNew==0 ){
+        p->rc = SQLITE_NOMEM;
+        break;
+      }
+      pIter->aRowidOffset = aNew;
+      pIter->nRowidOffset = nNew;
+    }
+
+    pIter->aRowidOffset[iRowidOffset++] = pIter->iLeafOffset;
+    pIter->iLeafOffset = i;
+  }
+  pIter->iRowidOffset = iRowidOffset;
+  fts5SegIterLoadNPos(p, pIter);
+}
+
+/*
+**
+*/
+static void fts5SegIterReverseNewPage(Fts5Index *p, Fts5SegIter *pIter){
+  assert( pIter->flags & FTS5_SEGITER_REVERSE );
+  assert( pIter->flags & FTS5_SEGITER_ONETERM );
+
+  fts5DataRelease(pIter->pLeaf);
+  pIter->pLeaf = 0;
+  while( p->rc==SQLITE_OK && pIter->iLeafPgno>pIter->iTermLeafPgno ){
+    Fts5Data *pNew;
+    pIter->iLeafPgno--;
+    pNew = fts5DataRead(p, FTS5_SEGMENT_ROWID(
+          pIter->pSeg->iSegid, pIter->iLeafPgno
+    ));
+    if( pNew ){
+      /* iTermLeafOffset may be equal to szLeaf if the term is the last
+      ** thing on the page - i.e. the first rowid is on the following page.
+      ** In this case leave pIter->pLeaf==0, this iterator is at EOF. */
+      if( pIter->iLeafPgno==pIter->iTermLeafPgno ){
+        assert( pIter->pLeaf==0 );
+        if( pIter->iTermLeafOffset<pNew->szLeaf ){
+          pIter->pLeaf = pNew;
+          pIter->iLeafOffset = pIter->iTermLeafOffset;
+        }
+      }else{
+        int iRowidOff;
+        iRowidOff = fts5LeafFirstRowidOff(pNew);
+        if( iRowidOff ){
+          if( iRowidOff>=pNew->szLeaf ){
+            p->rc = FTS5_CORRUPT;
+          }else{
+            pIter->pLeaf = pNew;
+            pIter->iLeafOffset = iRowidOff;
+          }
+        }
+      }
+
+      if( pIter->pLeaf ){
+        u8 *a = &pIter->pLeaf->p[pIter->iLeafOffset];
+        pIter->iLeafOffset += fts5GetVarint(a, (u64*)&pIter->iRowid);
+        break;
+      }else{
+        fts5DataRelease(pNew);
+      }
+    }
+  }
+
+  if( pIter->pLeaf ){
+    pIter->iEndofDoclist = pIter->pLeaf->nn+1;
+    fts5SegIterReverseInitPage(p, pIter);
+  }
+}
+
+/*
+** Return true if the iterator passed as the second argument currently
+** points to a delete marker. A delete marker is an entry with a 0 byte
+** position-list.
+*/
+static int fts5MultiIterIsEmpty(Fts5Index *p, Fts5Iter *pIter){
+  Fts5SegIter *pSeg = &pIter->aSeg[pIter->aFirst[1].iFirst];
+  return (p->rc==SQLITE_OK && pSeg->pLeaf && pSeg->nPos==0);
+}
+
+/*
+** Advance iterator pIter to the next entry.
+**
+** This version of fts5SegIterNext() is only used by reverse iterators.
+*/
+static void fts5SegIterNext_Reverse(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  int *pbUnused                   /* Unused */
+){
+  assert( pIter->flags & FTS5_SEGITER_REVERSE );
+  assert( pIter->pNextLeaf==0 );
+  UNUSED_PARAM(pbUnused);
+
+  if( pIter->iRowidOffset>0 ){
+    u8 *a = pIter->pLeaf->p;
+    int iOff;
+    u64 iDelta;
+
+    pIter->iRowidOffset--;
+    pIter->iLeafOffset = pIter->aRowidOffset[pIter->iRowidOffset];
+    fts5SegIterLoadNPos(p, pIter);
+    iOff = pIter->iLeafOffset;
+    if( p->pConfig->eDetail!=FTS5_DETAIL_NONE ){
+      iOff += pIter->nPos;
+    }
+    fts5GetVarint(&a[iOff], &iDelta);
+    pIter->iRowid -= iDelta;
+  }else{
+    fts5SegIterReverseNewPage(p, pIter);
+  }
+}
+
+/*
+** Advance iterator pIter to the next entry.
+**
+** This version of fts5SegIterNext() is only used if detail=none and the
+** iterator is not a reverse direction iterator.
+*/
+static void fts5SegIterNext_None(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  int *pbNewTerm                  /* OUT: Set for new term */
+){
+  int iOff;
+
+  assert( p->rc==SQLITE_OK );
+  assert( (pIter->flags & FTS5_SEGITER_REVERSE)==0 );
+  assert( p->pConfig->eDetail==FTS5_DETAIL_NONE );
+
+  ASSERT_SZLEAF_OK(pIter->pLeaf);
+  iOff = pIter->iLeafOffset;
+
+  /* Next entry is on the next page */
+  while( pIter->pSeg && iOff>=pIter->pLeaf->szLeaf ){
+    fts5SegIterNextPage(p, pIter);
+    if( p->rc || pIter->pLeaf==0 ) return;
+    pIter->iRowid = 0;
+    iOff = 4;
+  }
+
+  if( iOff<pIter->iEndofDoclist ){
+    /* Next entry is on the current page */
+    u64 iDelta;
+    iOff += sqlite3Fts5GetVarint(&pIter->pLeaf->p[iOff], (u64*)&iDelta);
+    pIter->iLeafOffset = iOff;
+    pIter->iRowid += iDelta;
+  }else if( (pIter->flags & FTS5_SEGITER_ONETERM)==0 ){
+    if( pIter->pSeg ){
+      int nKeep = 0;
+      if( iOff!=fts5LeafFirstTermOff(pIter->pLeaf) ){
+        iOff += fts5GetVarint32(&pIter->pLeaf->p[iOff], nKeep);
+      }
+      pIter->iLeafOffset = iOff;
+      fts5SegIterLoadTerm(p, pIter, nKeep);
+    }else{
+      const u8 *pList = 0;
+      const char *zTerm = 0;
+      int nTerm = 0;
+      int nList;
+      sqlite3Fts5HashScanNext(p->pHash);
+      sqlite3Fts5HashScanEntry(p->pHash, &zTerm, &nTerm, &pList, &nList);
+      if( pList==0 ) goto next_none_eof;
+      pIter->pLeaf->p = (u8*)pList;
+      pIter->pLeaf->nn = nList;
+      pIter->pLeaf->szLeaf = nList;
+      pIter->iEndofDoclist = nList;
+      sqlite3Fts5BufferSet(&p->rc,&pIter->term, nTerm, (u8*)zTerm);
+      pIter->iLeafOffset = fts5GetVarint(pList, (u64*)&pIter->iRowid);
+    }
+
+    if( pbNewTerm ) *pbNewTerm = 1;
+  }else{
+    goto next_none_eof;
+  }
+
+  fts5SegIterLoadNPos(p, pIter);
+
+  return;
+ next_none_eof:
+  fts5DataRelease(pIter->pLeaf);
+  pIter->pLeaf = 0;
+}
+
+
+/*
+** Advance iterator pIter to the next entry.
+**
+** If an error occurs, Fts5Index.rc is set to an appropriate error code. It
+** is not considered an error if the iterator reaches EOF. If an error has
+** already occurred when this function is called, it is a no-op.
+*/
+static void fts5SegIterNext(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  int *pbNewTerm                  /* OUT: Set for new term */
+){
+  Fts5Data *pLeaf = pIter->pLeaf;
+  int iOff;
+  int bNewTerm = 0;
+  int nKeep = 0;
+  u8 *a;
+  int n;
+
+  assert( pbNewTerm==0 || *pbNewTerm==0 );
+  assert( p->pConfig->eDetail!=FTS5_DETAIL_NONE );
+
+  /* Search for the end of the position list within the current page. */
+  a = pLeaf->p;
+  n = pLeaf->szLeaf;
+
+  ASSERT_SZLEAF_OK(pLeaf);
+  iOff = pIter->iLeafOffset + pIter->nPos;
+
+  if( iOff<n ){
+    /* The next entry is on the current page. */
+    assert_nc( iOff<=pIter->iEndofDoclist );
+    if( iOff>=pIter->iEndofDoclist ){
+      bNewTerm = 1;
+      if( iOff!=fts5LeafFirstTermOff(pLeaf) ){
+        iOff += fts5GetVarint32(&a[iOff], nKeep);
+      }
+    }else{
+      u64 iDelta;
+      iOff += sqlite3Fts5GetVarint(&a[iOff], &iDelta);
+      pIter->iRowid += iDelta;
+      assert_nc( iDelta>0 );
+    }
+    pIter->iLeafOffset = iOff;
+
+  }else if( pIter->pSeg==0 ){
+    const u8 *pList = 0;
+    const char *zTerm = 0;
+    int nTerm = 0;
+    int nList = 0;
+    assert( (pIter->flags & FTS5_SEGITER_ONETERM) || pbNewTerm );
+    if( 0==(pIter->flags & FTS5_SEGITER_ONETERM) ){
+      sqlite3Fts5HashScanNext(p->pHash);
+      sqlite3Fts5HashScanEntry(p->pHash, &zTerm, &nTerm, &pList, &nList);
+    }
+    if( pList==0 ){
+      fts5DataRelease(pIter->pLeaf);
+      pIter->pLeaf = 0;
+    }else{
+      pIter->pLeaf->p = (u8*)pList;
+      pIter->pLeaf->nn = nList;
+      pIter->pLeaf->szLeaf = nList;
+      pIter->iEndofDoclist = nList+1;
+      sqlite3Fts5BufferSet(&p->rc, &pIter->term, nTerm, (u8*)zTerm);
+      pIter->iLeafOffset = fts5GetVarint(pList, (u64*)&pIter->iRowid);
+      *pbNewTerm = 1;
+    }
+  }else{
+    iOff = 0;
+    /* Next entry is not on the current page */
+    while( iOff==0 ){
+      fts5SegIterNextPage(p, pIter);
+      pLeaf = pIter->pLeaf;
+      if( pLeaf==0 ) break;
+      ASSERT_SZLEAF_OK(pLeaf);
+      if( (iOff = fts5LeafFirstRowidOff(pLeaf)) && iOff<pLeaf->szLeaf ){
+        iOff += sqlite3Fts5GetVarint(&pLeaf->p[iOff], (u64*)&pIter->iRowid);
+        pIter->iLeafOffset = iOff;
+
+        if( pLeaf->nn>pLeaf->szLeaf ){
+          pIter->iPgidxOff = pLeaf->szLeaf + fts5GetVarint32(
+              &pLeaf->p[pLeaf->szLeaf], pIter->iEndofDoclist
+          );
+        }
+      }
+      else if( pLeaf->nn>pLeaf->szLeaf ){
+        pIter->iPgidxOff = pLeaf->szLeaf + fts5GetVarint32(
+            &pLeaf->p[pLeaf->szLeaf], iOff
+        );
+        pIter->iLeafOffset = iOff;
+        pIter->iEndofDoclist = iOff;
+        bNewTerm = 1;
+      }
+      assert_nc( iOff<pLeaf->szLeaf );
+      if( iOff>pLeaf->szLeaf ){
+        p->rc = FTS5_CORRUPT;
+        return;
+      }
+    }
+  }
+
+  /* Check if the iterator is now at EOF. If so, return early. */
+  if( pIter->pLeaf ){
+    if( bNewTerm ){
+      if( pIter->flags & FTS5_SEGITER_ONETERM ){
+        fts5DataRelease(pIter->pLeaf);
+        pIter->pLeaf = 0;
+      }else{
+        fts5SegIterLoadTerm(p, pIter, nKeep);
+        fts5SegIterLoadNPos(p, pIter);
+        if( pbNewTerm ) *pbNewTerm = 1;
+      }
+    }else{
+      /* The following could be done by calling fts5SegIterLoadNPos(). But
+      ** this block is particularly performance critical, so equivalent
+      ** code is inlined.  */
+      int nSz;
+      assert_nc( pIter->iLeafOffset<=pIter->pLeaf->nn );
+      fts5FastGetVarint32(pIter->pLeaf->p, pIter->iLeafOffset, nSz);
+      pIter->bDel = (nSz & 0x0001);
+      pIter->nPos = nSz>>1;
+      assert_nc( pIter->nPos>=0 );
+    }
+  }
+}
+
+#define SWAPVAL(T, a, b) { T tmp; tmp=a; a=b; b=tmp; }
+
+#define fts5IndexSkipVarint(a, iOff) {            \
+  int iEnd = iOff+9;                              \
+  while( (a[iOff++] & 0x80) && iOff<iEnd );       \
+}
+
+/*
+** Iterator pIter currently points to the first rowid in a doclist. This
+** function sets the iterator up so that iterates in reverse order through
+** the doclist.
+*/
+static void fts5SegIterReverse(Fts5Index *p, Fts5SegIter *pIter){
+  Fts5DlidxIter *pDlidx = pIter->pDlidx;
+  Fts5Data *pLast = 0;
+  int pgnoLast = 0;
+
+  if( pDlidx && p->pConfig->iVersion==FTS5_CURRENT_VERSION ){
+    int iSegid = pIter->pSeg->iSegid;
+    pgnoLast = fts5DlidxIterPgno(pDlidx);
+    pLast = fts5LeafRead(p, FTS5_SEGMENT_ROWID(iSegid, pgnoLast));
+  }else{
+    Fts5Data *pLeaf = pIter->pLeaf;         /* Current leaf data */
+
+    /* Currently, Fts5SegIter.iLeafOffset points to the first byte of
+    ** position-list content for the current rowid. Back it up so that it
+    ** points to the start of the position-list size field. */
+    int iPoslist;
+    if( pIter->iTermLeafPgno==pIter->iLeafPgno ){
+      iPoslist = pIter->iTermLeafOffset;
+    }else{
+      iPoslist = 4;
+    }
+    fts5IndexSkipVarint(pLeaf->p, iPoslist);
+    pIter->iLeafOffset = iPoslist;
+
+    /* If this condition is true then the largest rowid for the current
+    ** term may not be stored on the current page. So search forward to
+    ** see where said rowid really is.  */
+    if( pIter->iEndofDoclist>=pLeaf->szLeaf ){
+      int pgno;
+      Fts5StructureSegment *pSeg = pIter->pSeg;
+
+      /* The last rowid in the doclist may not be on the current page. Search
+      ** forward to find the page containing the last rowid.  */
+      for(pgno=pIter->iLeafPgno+1; !p->rc && pgno<=pSeg->pgnoLast; pgno++){
+        i64 iAbs = FTS5_SEGMENT_ROWID(pSeg->iSegid, pgno);
+        Fts5Data *pNew = fts5LeafRead(p, iAbs);
+        if( pNew ){
+          int iRowid, bTermless;
+          iRowid = fts5LeafFirstRowidOff(pNew);
+          bTermless = fts5LeafIsTermless(pNew);
+          if( iRowid ){
+            SWAPVAL(Fts5Data*, pNew, pLast);
+            pgnoLast = pgno;
+          }
+          fts5DataRelease(pNew);
+          if( bTermless==0 ) break;
+        }
+      }
+    }
+  }
+
+  /* If pLast is NULL at this point, then the last rowid for this doclist
+  ** lies on the page currently indicated by the iterator. In this case
+  ** pIter->iLeafOffset is already set to point to the position-list size
+  ** field associated with the first relevant rowid on the page.
+  **
+  ** Or, if pLast is non-NULL, then it is the page that contains the last
+  ** rowid. In this case configure the iterator so that it points to the
+  ** first rowid on this page.
+  */
+  if( pLast ){
+    int iOff;
+    fts5DataRelease(pIter->pLeaf);
+    pIter->pLeaf = pLast;
+    pIter->iLeafPgno = pgnoLast;
+    iOff = fts5LeafFirstRowidOff(pLast);
+    if( iOff>pLast->szLeaf ){
+      p->rc = FTS5_CORRUPT;
+      return;
+    }
+    iOff += fts5GetVarint(&pLast->p[iOff], (u64*)&pIter->iRowid);
+    pIter->iLeafOffset = iOff;
+
+    if( fts5LeafIsTermless(pLast) ){
+      pIter->iEndofDoclist = pLast->nn+1;
+    }else{
+      pIter->iEndofDoclist = fts5LeafFirstTermOff(pLast);
+    }
+  }
+
+  fts5SegIterReverseInitPage(p, pIter);
+}
+
+/*
+** Iterator pIter currently points to the first rowid of a doclist.
+** There is a doclist-index associated with the final term on the current
+** page. If the current term is the last term on the page, load the
+** doclist-index from disk and initialize an iterator at (pIter->pDlidx).
+*/
+static void fts5SegIterLoadDlidx(Fts5Index *p, Fts5SegIter *pIter){
+  int iSeg = pIter->pSeg->iSegid;
+  int bRev = (pIter->flags & FTS5_SEGITER_REVERSE);
+  Fts5Data *pLeaf = pIter->pLeaf; /* Current leaf data */
+
+  assert( pIter->flags & FTS5_SEGITER_ONETERM );
+  assert( pIter->pDlidx==0 );
+
+  /* Check if the current doclist ends on this page. If it does, return
+  ** early without loading the doclist-index (as it belongs to a different
+  ** term. */
+  if( pIter->iTermLeafPgno==pIter->iLeafPgno
+   && pIter->iEndofDoclist<pLeaf->szLeaf
+  ){
+    return;
+  }
+
+  pIter->pDlidx = fts5DlidxIterInit(p, bRev, iSeg, pIter->iTermLeafPgno);
+}
+
+/*
+** The iterator object passed as the second argument currently contains
+** no valid values except for the Fts5SegIter.pLeaf member variable. This
+** function searches the leaf page for a term matching (pTerm/nTerm).
+**
+** If the specified term is found on the page, then the iterator is left
+** pointing to it. If argument bGe is zero and the term is not found,
+** the iterator is left pointing at EOF.
+**
+** If bGe is non-zero and the specified term is not found, then the
+** iterator is left pointing to the smallest term in the segment that
+** is larger than the specified term, even if this term is not on the
+** current page.
+*/
+static void fts5LeafSeek(
+  Fts5Index *p,                   /* Leave any error code here */
+  int bGe,                        /* True for a >= search */
+  Fts5SegIter *pIter,             /* Iterator to seek */
+  const u8 *pTerm, int nTerm      /* Term to search for */
+){
+  u32 iOff;
+  const u8 *a = pIter->pLeaf->p;
+  u32 n = (u32)pIter->pLeaf->nn;
+
+  u32 nMatch = 0;
+  u32 nKeep = 0;
+  u32 nNew = 0;
+  u32 iTermOff;
+  u32 iPgidx;                     /* Current offset in pgidx */
+  int bEndOfPage = 0;
+
+  assert( p->rc==SQLITE_OK );
+
+  iPgidx = (u32)pIter->pLeaf->szLeaf;
+  iPgidx += fts5GetVarint32(&a[iPgidx], iTermOff);
+  iOff = iTermOff;
+  if( iOff>n ){
+    p->rc = FTS5_CORRUPT;
+    return;
+  }
+
+  while( 1 ){
+
+    /* Figure out how many new bytes are in this term */
+    fts5FastGetVarint32(a, iOff, nNew);
+    if( nKeep<nMatch ){
+      goto search_failed;
+    }
+
+    assert( nKeep>=nMatch );
+    if( nKeep==nMatch ){
+      u32 nCmp;
+      u32 i;
+      nCmp = (u32)MIN(nNew, nTerm-nMatch);
+      for(i=0; i<nCmp; i++){
+        if( a[iOff+i]!=pTerm[nMatch+i] ) break;
+      }
+      nMatch += i;
+
+      if( (u32)nTerm==nMatch ){
+        if( i==nNew ){
+          goto search_success;
+        }else{
+          goto search_failed;
+        }
+      }else if( i<nNew && a[iOff+i]>pTerm[nMatch] ){
+        goto search_failed;
+      }
+    }
+
+    if( iPgidx>=n ){
+      bEndOfPage = 1;
+      break;
+    }
+
+    iPgidx += fts5GetVarint32(&a[iPgidx], nKeep);
+    iTermOff += nKeep;
+    iOff = iTermOff;
+
+    if( iOff>=n ){
+      p->rc = FTS5_CORRUPT;
+      return;
+    }
+
+    /* Read the nKeep field of the next term. */
+    fts5FastGetVarint32(a, iOff, nKeep);
+  }
+
+ search_failed:
+  if( bGe==0 ){
+    fts5DataRelease(pIter->pLeaf);
+    pIter->pLeaf = 0;
+    return;
+  }else if( bEndOfPage ){
+    do {
+      fts5SegIterNextPage(p, pIter);
+      if( pIter->pLeaf==0 ) return;
+      a = pIter->pLeaf->p;
+      if( fts5LeafIsTermless(pIter->pLeaf)==0 ){
+        iPgidx = (u32)pIter->pLeaf->szLeaf;
+        iPgidx += fts5GetVarint32(&pIter->pLeaf->p[iPgidx], iOff);
+        if( iOff<4 || (i64)iOff>=pIter->pLeaf->szLeaf ){
+          p->rc = FTS5_CORRUPT;
+          return;
+        }else{
+          nKeep = 0;
+          iTermOff = iOff;
+          n = (u32)pIter->pLeaf->nn;
+          iOff += fts5GetVarint32(&a[iOff], nNew);
+          break;
+        }
+      }
+    }while( 1 );
+  }
+
+ search_success:
+  if( (i64)iOff+nNew>n || nNew<1 ){
+    p->rc = FTS5_CORRUPT;
+    return;
+  }
+  pIter->iLeafOffset = iOff + nNew;
+  pIter->iTermLeafOffset = pIter->iLeafOffset;
+  pIter->iTermLeafPgno = pIter->iLeafPgno;
+
+  fts5BufferSet(&p->rc, &pIter->term, nKeep, pTerm);
+  fts5BufferAppendBlob(&p->rc, &pIter->term, nNew, &a[iOff]);
+
+  if( iPgidx>=n ){
+    pIter->iEndofDoclist = pIter->pLeaf->nn+1;
+  }else{
+    int nExtra;
+    iPgidx += fts5GetVarint32(&a[iPgidx], nExtra);
+    pIter->iEndofDoclist = iTermOff + nExtra;
+  }
+  pIter->iPgidxOff = iPgidx;
+
+  fts5SegIterLoadRowid(p, pIter);
+  fts5SegIterLoadNPos(p, pIter);
+}
+
+static sqlite3_stmt *fts5IdxSelectStmt(Fts5Index *p){
+  if( p->pIdxSelect==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pIdxSelect, sqlite3_mprintf(
+          "SELECT pgno FROM '%q'.'%q_idx' WHERE "
+          "segid=? AND term<=? ORDER BY term DESC LIMIT 1",
+          pConfig->zDb, pConfig->zName
+    ));
+  }
+  return p->pIdxSelect;
+}
+
+/*
+** Initialize the object pIter to point to term pTerm/nTerm within segment
+** pSeg. If there is no such term in the index, the iterator is set to EOF.
+**
+** If an error occurs, Fts5Index.rc is set to an appropriate error code. If
+** an error has already occurred when this function is called, it is a no-op.
+*/
+static void fts5SegIterSeekInit(
+  Fts5Index *p,                   /* FTS5 backend */
+  const u8 *pTerm, int nTerm,     /* Term to seek to */
+  int flags,                      /* Mask of FTS5INDEX_XXX flags */
+  Fts5StructureSegment *pSeg,     /* Description of segment */
+  Fts5SegIter *pIter              /* Object to populate */
+){
+  int iPg = 1;
+  int bGe = (flags & FTS5INDEX_QUERY_SCAN);
+  int bDlidx = 0;                 /* True if there is a doclist-index */
+  sqlite3_stmt *pIdxSelect = 0;
+
+  assert( bGe==0 || (flags & FTS5INDEX_QUERY_DESC)==0 );
+  assert( pTerm && nTerm );
+  memset(pIter, 0, sizeof(*pIter));
+  pIter->pSeg = pSeg;
+
+  /* This block sets stack variable iPg to the leaf page number that may
+  ** contain term (pTerm/nTerm), if it is present in the segment. */
+  pIdxSelect = fts5IdxSelectStmt(p);
+  if( p->rc ) return;
+  sqlite3_bind_int(pIdxSelect, 1, pSeg->iSegid);
+  sqlite3_bind_blob(pIdxSelect, 2, pTerm, nTerm, SQLITE_STATIC);
+  if( SQLITE_ROW==sqlite3_step(pIdxSelect) ){
+    i64 val = sqlite3_column_int(pIdxSelect, 0);
+    iPg = (int)(val>>1);
+    bDlidx = (val & 0x0001);
+  }
+  p->rc = sqlite3_reset(pIdxSelect);
+  sqlite3_bind_null(pIdxSelect, 2);
+
+  if( iPg<pSeg->pgnoFirst ){
+    iPg = pSeg->pgnoFirst;
+    bDlidx = 0;
+  }
+
+  pIter->iLeafPgno = iPg - 1;
+  fts5SegIterNextPage(p, pIter);
+
+  if( pIter->pLeaf ){
+    fts5LeafSeek(p, bGe, pIter, pTerm, nTerm);
+  }
+
+  if( p->rc==SQLITE_OK && (bGe==0 || (flags & FTS5INDEX_QUERY_SCANONETERM)) ){
+    pIter->flags |= FTS5_SEGITER_ONETERM;
+    if( pIter->pLeaf ){
+      if( flags & FTS5INDEX_QUERY_DESC ){
+        pIter->flags |= FTS5_SEGITER_REVERSE;
+      }
+      if( bDlidx ){
+        fts5SegIterLoadDlidx(p, pIter);
+      }
+      if( flags & FTS5INDEX_QUERY_DESC ){
+        fts5SegIterReverse(p, pIter);
+      }
+    }
+  }
+
+  fts5SegIterSetNext(p, pIter);
+  if( 0==(flags & FTS5INDEX_QUERY_SCANONETERM) ){
+    fts5SegIterAllocTombstone(p, pIter);
+  }
+
+  /* Either:
+  **
+  **   1) an error has occurred, or
+  **   2) the iterator points to EOF, or
+  **   3) the iterator points to an entry with term (pTerm/nTerm), or
+  **   4) the FTS5INDEX_QUERY_SCAN flag was set and the iterator points
+  **      to an entry with a term greater than or equal to (pTerm/nTerm).
+  */
+  assert_nc( p->rc!=SQLITE_OK                                       /* 1 */
+   || pIter->pLeaf==0                                               /* 2 */
+   || fts5BufferCompareBlob(&pIter->term, pTerm, nTerm)==0          /* 3 */
+   || (bGe && fts5BufferCompareBlob(&pIter->term, pTerm, nTerm)>0)  /* 4 */
+  );
+}
+
+
+/*
+** SQL used by fts5SegIterNextInit() to find the page to open.
+*/
+static sqlite3_stmt *fts5IdxNextStmt(Fts5Index *p){
+  if( p->pIdxNextSelect==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pIdxNextSelect, sqlite3_mprintf(
+          "SELECT pgno FROM '%q'.'%q_idx' WHERE "
+          "segid=? AND term>? ORDER BY term ASC LIMIT 1",
+          pConfig->zDb, pConfig->zName
+    ));
+
+  }
+  return p->pIdxNextSelect;
+}
+
+/*
+** This is similar to fts5SegIterSeekInit(), except that it initializes
+** the segment iterator to point to the first term following the page
+** with pToken/nToken on it.
+*/
+static void fts5SegIterNextInit(
+  Fts5Index *p,
+  const char *pTerm, int nTerm,
+  Fts5StructureSegment *pSeg,     /* Description of segment */
+  Fts5SegIter *pIter              /* Object to populate */
+){
+  int iPg = -1;                   /* Page of segment to open */
+  int bDlidx = 0;
+  sqlite3_stmt *pSel = 0;         /* SELECT to find iPg */
+
+  pSel = fts5IdxNextStmt(p);
+  if( pSel ){
+    assert( p->rc==SQLITE_OK );
+    sqlite3_bind_int(pSel, 1, pSeg->iSegid);
+    sqlite3_bind_blob(pSel, 2, pTerm, nTerm, SQLITE_STATIC);
+
+    if( sqlite3_step(pSel)==SQLITE_ROW ){
+      i64 val = sqlite3_column_int64(pSel, 0);
+      iPg = (int)(val>>1);
+      bDlidx = (val & 0x0001);
+    }
+    p->rc = sqlite3_reset(pSel);
+    sqlite3_bind_null(pSel, 2);
+    if( p->rc ) return;
+  }
+
+  memset(pIter, 0, sizeof(*pIter));
+  pIter->pSeg = pSeg;
+  pIter->flags |= FTS5_SEGITER_ONETERM;
+  if( iPg>=0 ){
+    pIter->iLeafPgno = iPg - 1;
+    fts5SegIterNextPage(p, pIter);
+    fts5SegIterSetNext(p, pIter);
+  }
+  if( pIter->pLeaf ){
+    const u8 *a = pIter->pLeaf->p;
+    int iTermOff = 0;
+
+    pIter->iPgidxOff = pIter->pLeaf->szLeaf;
+    pIter->iPgidxOff += fts5GetVarint32(&a[pIter->iPgidxOff], iTermOff);
+    pIter->iLeafOffset = iTermOff;
+    fts5SegIterLoadTerm(p, pIter, 0);
+    fts5SegIterLoadNPos(p, pIter);
+    if( bDlidx ) fts5SegIterLoadDlidx(p, pIter);
+
+    assert( p->rc!=SQLITE_OK ||
+        fts5BufferCompareBlob(&pIter->term, (const u8*)pTerm, nTerm)>0
+    );
+  }
+}
+
+/*
+** Initialize the object pIter to point to term pTerm/nTerm within the
+** in-memory hash table. If there is no such term in the hash-table, the
+** iterator is set to EOF.
+**
+** If an error occurs, Fts5Index.rc is set to an appropriate error code. If
+** an error has already occurred when this function is called, it is a no-op.
+*/
+static void fts5SegIterHashInit(
+  Fts5Index *p,                   /* FTS5 backend */
+  const u8 *pTerm, int nTerm,     /* Term to seek to */
+  int flags,                      /* Mask of FTS5INDEX_XXX flags */
+  Fts5SegIter *pIter              /* Object to populate */
+){
+  int nList = 0;
+  const u8 *z = 0;
+  int n = 0;
+  Fts5Data *pLeaf = 0;
+
+  assert( p->pHash );
+  assert( p->rc==SQLITE_OK );
+
+  if( pTerm==0 || (flags & FTS5INDEX_QUERY_SCAN) ){
+    const u8 *pList = 0;
+
+    p->rc = sqlite3Fts5HashScanInit(p->pHash, (const char*)pTerm, nTerm);
+    sqlite3Fts5HashScanEntry(p->pHash, (const char**)&z, &n, &pList, &nList);
+    if( pList ){
+      pLeaf = fts5IdxMalloc(p, sizeof(Fts5Data));
+      if( pLeaf ){
+        pLeaf->p = (u8*)pList;
+      }
+    }
+
+    /* The call to sqlite3Fts5HashScanInit() causes the hash table to
+    ** fill the size field of all existing position lists. This means they
+    ** can no longer be appended to. Since the only scenario in which they
+    ** can be appended to is if the previous operation on this table was
+    ** a DELETE, by clearing the Fts5Index.bDelete flag we can avoid this
+    ** possibility altogether.  */
+    p->bDelete = 0;
+  }else{
+    p->rc = sqlite3Fts5HashQuery(p->pHash, sizeof(Fts5Data),
+        (const char*)pTerm, nTerm, (void**)&pLeaf, &nList
+    );
+    if( pLeaf ){
+      pLeaf->p = (u8*)&pLeaf[1];
+    }
+    z = pTerm;
+    n = nTerm;
+    pIter->flags |= FTS5_SEGITER_ONETERM;
+  }
+
+  if( pLeaf ){
+    sqlite3Fts5BufferSet(&p->rc, &pIter->term, n, z);
+    pLeaf->nn = pLeaf->szLeaf = nList;
+    pIter->pLeaf = pLeaf;
+    pIter->iLeafOffset = fts5GetVarint(pLeaf->p, (u64*)&pIter->iRowid);
+    pIter->iEndofDoclist = pLeaf->nn;
+
+    if( flags & FTS5INDEX_QUERY_DESC ){
+      pIter->flags |= FTS5_SEGITER_REVERSE;
+      fts5SegIterReverseInitPage(p, pIter);
+    }else{
+      fts5SegIterLoadNPos(p, pIter);
+    }
+  }
+
+  fts5SegIterSetNext(p, pIter);
+}
+
+/*
+** Array ap[] contains n elements. Release each of these elements using
+** fts5DataRelease(). Then free the array itself using sqlite3_free().
+*/
+static void fts5IndexFreeArray(Fts5Data **ap, int n){
+  if( ap ){
+    int ii;
+    for(ii=0; ii<n; ii++){
+      fts5DataRelease(ap[ii]);
+    }
+    sqlite3_free(ap);
+  }
+}
+
+/*
+** Decrement the ref-count of the object passed as the only argument. If it
+** reaches 0, free it and its contents.
+*/
+static void fts5TombstoneArrayDelete(Fts5TombstoneArray *p){
+  if( p ){
+    p->nRef--;
+    if( p->nRef<=0 ){
+      int ii;
+      for(ii=0; ii<p->nTombstone; ii++){
+        fts5DataRelease(p->apTombstone[ii]);
+      }
+      sqlite3_free(p);
+    }
+  }
+}
+
+/*
+** Zero the iterator passed as the only argument.
+*/
+static void fts5SegIterClear(Fts5SegIter *pIter){
+  fts5BufferFree(&pIter->term);
+  fts5DataRelease(pIter->pLeaf);
+  fts5DataRelease(pIter->pNextLeaf);
+  fts5TombstoneArrayDelete(pIter->pTombArray);
+  fts5DlidxIterFree(pIter->pDlidx);
+  sqlite3_free(pIter->aRowidOffset);
+  memset(pIter, 0, sizeof(Fts5SegIter));
+}
+
+#ifdef SQLITE_DEBUG
+
+/*
+** This function is used as part of the big assert() procedure implemented by
+** fts5AssertMultiIterSetup(). It ensures that the result currently stored
+** in *pRes is the correct result of comparing the current positions of the
+** two iterators.
+*/
+static void fts5AssertComparisonResult(
+  Fts5Iter *pIter,
+  Fts5SegIter *p1,
+  Fts5SegIter *p2,
+  Fts5CResult *pRes
+){
+  int i1 = p1 - pIter->aSeg;
+  int i2 = p2 - pIter->aSeg;
+
+  if( p1->pLeaf || p2->pLeaf ){
+    if( p1->pLeaf==0 ){
+      assert( pRes->iFirst==i2 );
+    }else if( p2->pLeaf==0 ){
+      assert( pRes->iFirst==i1 );
+    }else{
+      int nMin = MIN(p1->term.n, p2->term.n);
+      int res = fts5Memcmp(p1->term.p, p2->term.p, nMin);
+      if( res==0 ) res = p1->term.n - p2->term.n;
+
+      if( res==0 ){
+        assert( pRes->bTermEq==1 );
+        assert( p1->iRowid!=p2->iRowid );
+        res = ((p1->iRowid > p2->iRowid)==pIter->bRev) ? -1 : 1;
+      }else{
+        assert( pRes->bTermEq==0 );
+      }
+
+      if( res<0 ){
+        assert( pRes->iFirst==i1 );
+      }else{
+        assert( pRes->iFirst==i2 );
+      }
+    }
+  }
+}
+
+/*
+** This function is a no-op unless SQLITE_DEBUG is defined when this module
+** is compiled. In that case, this function is essentially an assert()
+** statement used to verify that the contents of the pIter->aFirst[] array
+** are correct.
+*/
+static void fts5AssertMultiIterSetup(Fts5Index *p, Fts5Iter *pIter){
+  if( p->rc==SQLITE_OK ){
+    Fts5SegIter *pFirst = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+    int i;
+
+    assert( (pFirst->pLeaf==0)==pIter->base.bEof );
+
+    /* Check that pIter->iSwitchRowid is set correctly. */
+    for(i=0; i<pIter->nSeg; i++){
+      Fts5SegIter *p1 = &pIter->aSeg[i];
+      assert( p1==pFirst
+           || p1->pLeaf==0
+           || fts5BufferCompare(&pFirst->term, &p1->term)
+           || p1->iRowid==pIter->iSwitchRowid
+           || (p1->iRowid<pIter->iSwitchRowid)==pIter->bRev
+      );
+    }
+
+    for(i=0; i<pIter->nSeg; i+=2){
+      Fts5SegIter *p1 = &pIter->aSeg[i];
+      Fts5SegIter *p2 = &pIter->aSeg[i+1];
+      Fts5CResult *pRes = &pIter->aFirst[(pIter->nSeg + i) / 2];
+      fts5AssertComparisonResult(pIter, p1, p2, pRes);
+    }
+
+    for(i=1; i<(pIter->nSeg / 2); i+=2){
+      Fts5SegIter *p1 = &pIter->aSeg[ pIter->aFirst[i*2].iFirst ];
+      Fts5SegIter *p2 = &pIter->aSeg[ pIter->aFirst[i*2+1].iFirst ];
+      Fts5CResult *pRes = &pIter->aFirst[i];
+      fts5AssertComparisonResult(pIter, p1, p2, pRes);
+    }
+  }
+}
+#else
+# define fts5AssertMultiIterSetup(x,y)
+#endif
+
+/*
+** Do the comparison necessary to populate pIter->aFirst[iOut].
+**
+** If the returned value is non-zero, then it is the index of an entry
+** in the pIter->aSeg[] array that is (a) not at EOF, and (b) pointing
+** to a key that is a duplicate of another, higher priority,
+** segment-iterator in the pSeg->aSeg[] array.
+*/
+static int fts5MultiIterDoCompare(Fts5Iter *pIter, int iOut){
+  int i1;                         /* Index of left-hand Fts5SegIter */
+  int i2;                         /* Index of right-hand Fts5SegIter */
+  int iRes;
+  Fts5SegIter *p1;                /* Left-hand Fts5SegIter */
+  Fts5SegIter *p2;                /* Right-hand Fts5SegIter */
+  Fts5CResult *pRes = &pIter->aFirst[iOut];
+
+  assert( iOut<pIter->nSeg && iOut>0 );
+  assert( pIter->bRev==0 || pIter->bRev==1 );
+
+  if( iOut>=(pIter->nSeg/2) ){
+    i1 = (iOut - pIter->nSeg/2) * 2;
+    i2 = i1 + 1;
+  }else{
+    i1 = pIter->aFirst[iOut*2].iFirst;
+    i2 = pIter->aFirst[iOut*2+1].iFirst;
+  }
+  p1 = &pIter->aSeg[i1];
+  p2 = &pIter->aSeg[i2];
+
+  pRes->bTermEq = 0;
+  if( p1->pLeaf==0 ){           /* If p1 is at EOF */
+    iRes = i2;
+  }else if( p2->pLeaf==0 ){     /* If p2 is at EOF */
+    iRes = i1;
+  }else{
+    int res = fts5BufferCompare(&p1->term, &p2->term);
+    if( res==0 ){
+      assert_nc( i2>i1 );
+      assert_nc( i2!=0 );
+      pRes->bTermEq = 1;
+      if( p1->iRowid==p2->iRowid ){
+        return i2;
+      }
+      res = ((p1->iRowid > p2->iRowid)==pIter->bRev) ? -1 : +1;
+    }
+    assert( res!=0 );
+    if( res<0 ){
+      iRes = i1;
+    }else{
+      iRes = i2;
+    }
+  }
+
+  pRes->iFirst = (u16)iRes;
+  return 0;
+}
+
+/*
+** Move the seg-iter so that it points to the first rowid on page iLeafPgno.
+** It is an error if leaf iLeafPgno does not exist. Unless the db is
+** a 'secure-delete' db, if it contains no rowids then this is also an error.
+*/
+static void fts5SegIterGotoPage(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  int iLeafPgno
+){
+  assert( iLeafPgno>pIter->iLeafPgno );
+
+  if( iLeafPgno>pIter->pSeg->pgnoLast ){
+    p->rc = FTS5_CORRUPT;
+  }else{
+    fts5DataRelease(pIter->pNextLeaf);
+    pIter->pNextLeaf = 0;
+    pIter->iLeafPgno = iLeafPgno-1;
+
+    while( p->rc==SQLITE_OK ){
+      int iOff;
+      fts5SegIterNextPage(p, pIter);
+      if( pIter->pLeaf==0 ) break;
+      iOff = fts5LeafFirstRowidOff(pIter->pLeaf);
+      if( iOff>0 ){
+        u8 *a = pIter->pLeaf->p;
+        int n = pIter->pLeaf->szLeaf;
+        if( iOff<4 || iOff>=n ){
+          p->rc = FTS5_CORRUPT;
+        }else{
+          iOff += fts5GetVarint(&a[iOff], (u64*)&pIter->iRowid);
+          pIter->iLeafOffset = iOff;
+          fts5SegIterLoadNPos(p, pIter);
+        }
+        break;
+      }
+    }
+  }
+}
+
+/*
+** Advance the iterator passed as the second argument until it is at or
+** past rowid iFrom. Regardless of the value of iFrom, the iterator is
+** always advanced at least once.
+*/
+static void fts5SegIterNextFrom(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  i64 iMatch                      /* Advance iterator at least this far */
+){
+  int bRev = (pIter->flags & FTS5_SEGITER_REVERSE);
+  Fts5DlidxIter *pDlidx = pIter->pDlidx;
+  int iLeafPgno = pIter->iLeafPgno;
+  int bMove = 1;
+
+  assert( pIter->flags & FTS5_SEGITER_ONETERM );
+  assert( pIter->pDlidx );
+  assert( pIter->pLeaf );
+
+  if( bRev==0 ){
+    while( !fts5DlidxIterEof(p, pDlidx) && iMatch>fts5DlidxIterRowid(pDlidx) ){
+      iLeafPgno = fts5DlidxIterPgno(pDlidx);
+      fts5DlidxIterNext(p, pDlidx);
+    }
+    assert_nc( iLeafPgno>=pIter->iLeafPgno || p->rc );
+    if( iLeafPgno>pIter->iLeafPgno ){
+      fts5SegIterGotoPage(p, pIter, iLeafPgno);
+      bMove = 0;
+    }
+  }else{
+    assert( pIter->pNextLeaf==0 );
+    assert( iMatch<pIter->iRowid );
+    while( !fts5DlidxIterEof(p, pDlidx) && iMatch<fts5DlidxIterRowid(pDlidx) ){
+      fts5DlidxIterPrev(p, pDlidx);
+    }
+    iLeafPgno = fts5DlidxIterPgno(pDlidx);
+
+    assert( fts5DlidxIterEof(p, pDlidx) || iLeafPgno<=pIter->iLeafPgno );
+
+    if( iLeafPgno<pIter->iLeafPgno ){
+      pIter->iLeafPgno = iLeafPgno+1;
+      fts5SegIterReverseNewPage(p, pIter);
+      bMove = 0;
+    }
+  }
+
+  do{
+    if( bMove && p->rc==SQLITE_OK ) pIter->xNext(p, pIter, 0);
+    if( pIter->pLeaf==0 ) break;
+    if( bRev==0 && pIter->iRowid>=iMatch ) break;
+    if( bRev!=0 && pIter->iRowid<=iMatch ) break;
+    bMove = 1;
+  }while( p->rc==SQLITE_OK );
+}
+
+/*
+** Free the iterator object passed as the second argument.
+*/
+static void fts5MultiIterFree(Fts5Iter *pIter){
+  if( pIter ){
+    int i;
+    for(i=0; i<pIter->nSeg; i++){
+      fts5SegIterClear(&pIter->aSeg[i]);
+    }
+    fts5BufferFree(&pIter->poslist);
+    sqlite3_free(pIter);
+  }
+}
+
+static void fts5MultiIterAdvanced(
+  Fts5Index *p,                   /* FTS5 backend to iterate within */
+  Fts5Iter *pIter,                /* Iterator to update aFirst[] array for */
+  int iChanged,                   /* Index of sub-iterator just advanced */
+  int iMinset                     /* Minimum entry in aFirst[] to set */
+){
+  int i;
+  for(i=(pIter->nSeg+iChanged)/2; i>=iMinset && p->rc==SQLITE_OK; i=i/2){
+    int iEq;
+    if( (iEq = fts5MultiIterDoCompare(pIter, i)) ){
+      Fts5SegIter *pSeg = &pIter->aSeg[iEq];
+      assert( p->rc==SQLITE_OK );
+      pSeg->xNext(p, pSeg, 0);
+      i = pIter->nSeg + iEq;
+    }
+  }
+}
+
+/*
+** Sub-iterator iChanged of iterator pIter has just been advanced. It still
+** points to the same term though - just a different rowid. This function
+** attempts to update the contents of the pIter->aFirst[] accordingly.
+** If it does so successfully, 0 is returned. Otherwise 1.
+**
+** If non-zero is returned, the caller should call fts5MultiIterAdvanced()
+** on the iterator instead. That function does the same as this one, except
+** that it deals with more complicated cases as well.
+*/
+static int fts5MultiIterAdvanceRowid(
+  Fts5Iter *pIter,                /* Iterator to update aFirst[] array for */
+  int iChanged,                   /* Index of sub-iterator just advanced */
+  Fts5SegIter **ppFirst
+){
+  Fts5SegIter *pNew = &pIter->aSeg[iChanged];
+
+  if( pNew->iRowid==pIter->iSwitchRowid
+   || (pNew->iRowid<pIter->iSwitchRowid)==pIter->bRev
+  ){
+    int i;
+    Fts5SegIter *pOther = &pIter->aSeg[iChanged ^ 0x0001];
+    pIter->iSwitchRowid = pIter->bRev ? SMALLEST_INT64 : LARGEST_INT64;
+    for(i=(pIter->nSeg+iChanged)/2; 1; i=i/2){
+      Fts5CResult *pRes = &pIter->aFirst[i];
+
+      assert( pNew->pLeaf );
+      assert( pRes->bTermEq==0 || pOther->pLeaf );
+
+      if( pRes->bTermEq ){
+        if( pNew->iRowid==pOther->iRowid ){
+          return 1;
+        }else if( (pOther->iRowid>pNew->iRowid)==pIter->bRev ){
+          pIter->iSwitchRowid = pOther->iRowid;
+          pNew = pOther;
+        }else if( (pOther->iRowid>pIter->iSwitchRowid)==pIter->bRev ){
+          pIter->iSwitchRowid = pOther->iRowid;
+        }
+      }
+      pRes->iFirst = (u16)(pNew - pIter->aSeg);
+      if( i==1 ) break;
+
+      pOther = &pIter->aSeg[ pIter->aFirst[i ^ 0x0001].iFirst ];
+    }
+  }
+
+  *ppFirst = pNew;
+  return 0;
+}
+
+/*
+** Set the pIter->bEof variable based on the state of the sub-iterators.
+*/
+static void fts5MultiIterSetEof(Fts5Iter *pIter){
+  Fts5SegIter *pSeg = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+  pIter->base.bEof = pSeg->pLeaf==0;
+  pIter->iSwitchRowid = pSeg->iRowid;
+}
+
+/*
+** The argument to this macro must be an Fts5Data structure containing a
+** tombstone hash page. This macro returns the key-size of the hash-page.
+*/
+#define TOMBSTONE_KEYSIZE(pPg) (pPg->p[0]==4 ? 4 : 8)
+
+#define TOMBSTONE_NSLOT(pPg)   \
+  ((pPg->nn > 16) ? ((pPg->nn-8) / TOMBSTONE_KEYSIZE(pPg)) : 1)
+
+/*
+** Query a single tombstone hash table for rowid iRowid. Return true if
+** it is found or false otherwise. The tombstone hash table is one of
+** nHashTable tables.
+*/
+static int fts5IndexTombstoneQuery(
+  Fts5Data *pHash,                /* Hash table page to query */
+  int nHashTable,                 /* Number of pages attached to segment */
+  u64 iRowid                      /* Rowid to query hash for */
+){
+  const int szKey = TOMBSTONE_KEYSIZE(pHash);
+  const int nSlot = TOMBSTONE_NSLOT(pHash);
+  int iSlot = (iRowid / nHashTable) % nSlot;
+  int nCollide = nSlot;
+
+  if( iRowid==0 ){
+    return pHash->p[1];
+  }else if( szKey==4 ){
+    u32 *aSlot = (u32*)&pHash->p[8];
+    while( aSlot[iSlot] ){
+      if( fts5GetU32((u8*)&aSlot[iSlot])==iRowid ) return 1;
+      if( nCollide--==0 ) break;
+      iSlot = (iSlot+1)%nSlot;
+    }
+  }else{
+    u64 *aSlot = (u64*)&pHash->p[8];
+    while( aSlot[iSlot] ){
+      if( fts5GetU64((u8*)&aSlot[iSlot])==iRowid ) return 1;
+      if( nCollide--==0 ) break;
+      iSlot = (iSlot+1)%nSlot;
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Return true if the iterator passed as the only argument points
+** to an segment entry for which there is a tombstone. Return false
+** if there is no tombstone or if the iterator is already at EOF.
+*/
+static int fts5MultiIterIsDeleted(Fts5Iter *pIter){
+  int iFirst = pIter->aFirst[1].iFirst;
+  Fts5SegIter *pSeg = &pIter->aSeg[iFirst];
+  Fts5TombstoneArray *pArray = pSeg->pTombArray;
+
+  if( pSeg->pLeaf && pArray ){
+    /* Figure out which page the rowid might be present on. */
+    int iPg = ((u64)pSeg->iRowid) % pArray->nTombstone;
+    assert( iPg>=0 );
+
+    /* If tombstone hash page iPg has not yet been loaded from the
+    ** database, load it now. */
+    if( pArray->apTombstone[iPg]==0 ){
+      pArray->apTombstone[iPg] = fts5DataRead(pIter->pIndex,
+          FTS5_TOMBSTONE_ROWID(pSeg->pSeg->iSegid, iPg)
+      );
+      if( pArray->apTombstone[iPg]==0 ) return 0;
+    }
+
+    return fts5IndexTombstoneQuery(
+        pArray->apTombstone[iPg],
+        pArray->nTombstone,
+        pSeg->iRowid
+    );
+  }
+
+  return 0;
+}
+
+/*
+** Move the iterator to the next entry.
+**
+** If an error occurs, an error code is left in Fts5Index.rc. It is not
+** considered an error if the iterator reaches EOF, or if it is already at
+** EOF when this function is called.
+*/
+static void fts5MultiIterNext(
+  Fts5Index *p,
+  Fts5Iter *pIter,
+  int bFrom,                      /* True if argument iFrom is valid */
+  i64 iFrom                       /* Advance at least as far as this */
+){
+  int bUseFrom = bFrom;
+  assert( pIter->base.bEof==0 );
+  while( p->rc==SQLITE_OK ){
+    int iFirst = pIter->aFirst[1].iFirst;
+    int bNewTerm = 0;
+    Fts5SegIter *pSeg = &pIter->aSeg[iFirst];
+    assert( p->rc==SQLITE_OK );
+    if( bUseFrom && pSeg->pDlidx ){
+      fts5SegIterNextFrom(p, pSeg, iFrom);
+    }else{
+      pSeg->xNext(p, pSeg, &bNewTerm);
+    }
+
+    if( pSeg->pLeaf==0 || bNewTerm
+     || fts5MultiIterAdvanceRowid(pIter, iFirst, &pSeg)
+    ){
+      fts5MultiIterAdvanced(p, pIter, iFirst, 1);
+      fts5MultiIterSetEof(pIter);
+      pSeg = &pIter->aSeg[pIter->aFirst[1].iFirst];
+      if( pSeg->pLeaf==0 ) return;
+    }
+
+    fts5AssertMultiIterSetup(p, pIter);
+    assert( pSeg==&pIter->aSeg[pIter->aFirst[1].iFirst] && pSeg->pLeaf );
+    if( (pIter->bSkipEmpty==0 || pSeg->nPos)
+      && 0==fts5MultiIterIsDeleted(pIter)
+    ){
+      pIter->xSetOutputs(pIter, pSeg);
+      return;
+    }
+    bUseFrom = 0;
+  }
+}
+
+static void fts5MultiIterNext2(
+  Fts5Index *p,
+  Fts5Iter *pIter,
+  int *pbNewTerm                  /* OUT: True if *might* be new term */
+){
+  assert( pIter->bSkipEmpty );
+  if( p->rc==SQLITE_OK ){
+    *pbNewTerm = 0;
+    do{
+      int iFirst = pIter->aFirst[1].iFirst;
+      Fts5SegIter *pSeg = &pIter->aSeg[iFirst];
+      int bNewTerm = 0;
+
+      assert( p->rc==SQLITE_OK );
+      pSeg->xNext(p, pSeg, &bNewTerm);
+      if( pSeg->pLeaf==0 || bNewTerm
+       || fts5MultiIterAdvanceRowid(pIter, iFirst, &pSeg)
+      ){
+        fts5MultiIterAdvanced(p, pIter, iFirst, 1);
+        fts5MultiIterSetEof(pIter);
+        *pbNewTerm = 1;
+      }
+      fts5AssertMultiIterSetup(p, pIter);
+
+    }while( (fts5MultiIterIsEmpty(p, pIter) || fts5MultiIterIsDeleted(pIter))
+         && (p->rc==SQLITE_OK)
+    );
+  }
+}
+
+static void fts5IterSetOutputs_Noop(Fts5Iter *pUnused1, Fts5SegIter *pUnused2){
+  UNUSED_PARAM2(pUnused1, pUnused2);
+}
+
+static Fts5Iter *fts5MultiIterAlloc(
+  Fts5Index *p,                   /* FTS5 backend to iterate within */
+  int nSeg
+){
+  Fts5Iter *pNew;
+  i64 nSlot;                      /* Power of two >= nSeg */
+
+  for(nSlot=2; nSlot<nSeg; nSlot=nSlot*2);
+  pNew = fts5IdxMalloc(p,
+      sizeof(Fts5Iter) +                  /* pNew */
+      sizeof(Fts5SegIter) * (nSlot-1) +   /* pNew->aSeg[] */
+      sizeof(Fts5CResult) * nSlot         /* pNew->aFirst[] */
+  );
+  if( pNew ){
+    pNew->nSeg = nSlot;
+    pNew->aFirst = (Fts5CResult*)&pNew->aSeg[nSlot];
+    pNew->pIndex = p;
+    pNew->xSetOutputs = fts5IterSetOutputs_Noop;
+  }
+  return pNew;
+}
+
+static void fts5PoslistCallback(
+  Fts5Index *pUnused,
+  void *pContext,
+  const u8 *pChunk, int nChunk
+){
+  UNUSED_PARAM(pUnused);
+  assert_nc( nChunk>=0 );
+  if( nChunk>0 ){
+    fts5BufferSafeAppendBlob((Fts5Buffer*)pContext, pChunk, nChunk);
+  }
+}
+
+typedef struct PoslistCallbackCtx PoslistCallbackCtx;
+struct PoslistCallbackCtx {
+  Fts5Buffer *pBuf;               /* Append to this buffer */
+  Fts5Colset *pColset;            /* Restrict matches to this column */
+  int eState;                     /* See above */
+};
+
+typedef struct PoslistOffsetsCtx PoslistOffsetsCtx;
+struct PoslistOffsetsCtx {
+  Fts5Buffer *pBuf;               /* Append to this buffer */
+  Fts5Colset *pColset;            /* Restrict matches to this column */
+  int iRead;
+  int iWrite;
+};
+
+/*
+** TODO: Make this more efficient!
+*/
+static int fts5IndexColsetTest(Fts5Colset *pColset, int iCol){
+  int i;
+  for(i=0; i<pColset->nCol; i++){
+    if( pColset->aiCol[i]==iCol ) return 1;
+  }
+  return 0;
+}
+
+static void fts5PoslistOffsetsCallback(
+  Fts5Index *pUnused,
+  void *pContext,
+  const u8 *pChunk, int nChunk
+){
+  PoslistOffsetsCtx *pCtx = (PoslistOffsetsCtx*)pContext;
+  UNUSED_PARAM(pUnused);
+  assert_nc( nChunk>=0 );
+  if( nChunk>0 ){
+    int i = 0;
+    while( i<nChunk ){
+      int iVal;
+      i += fts5GetVarint32(&pChunk[i], iVal);
+      iVal += pCtx->iRead - 2;
+      pCtx->iRead = iVal;
+      if( fts5IndexColsetTest(pCtx->pColset, iVal) ){
+        fts5BufferSafeAppendVarint(pCtx->pBuf, iVal + 2 - pCtx->iWrite);
+        pCtx->iWrite = iVal;
+      }
+    }
+  }
+}
+
+static void fts5PoslistFilterCallback(
+  Fts5Index *pUnused,
+  void *pContext,
+  const u8 *pChunk, int nChunk
+){
+  PoslistCallbackCtx *pCtx = (PoslistCallbackCtx*)pContext;
+  UNUSED_PARAM(pUnused);
+  assert_nc( nChunk>=0 );
+  if( nChunk>0 ){
+    /* Search through to find the first varint with value 1. This is the
+    ** start of the next columns hits. */
+    int i = 0;
+    int iStart = 0;
+
+    if( pCtx->eState==2 ){
+      int iCol;
+      fts5FastGetVarint32(pChunk, i, iCol);
+      if( fts5IndexColsetTest(pCtx->pColset, iCol) ){
+        pCtx->eState = 1;
+        fts5BufferSafeAppendVarint(pCtx->pBuf, 1);
+      }else{
+        pCtx->eState = 0;
+      }
+    }
+
+    do {
+      while( i<nChunk && pChunk[i]!=0x01 ){
+        while( pChunk[i] & 0x80 ) i++;
+        i++;
+      }
+      if( pCtx->eState ){
+        fts5BufferSafeAppendBlob(pCtx->pBuf, &pChunk[iStart], i-iStart);
+      }
+      if( i<nChunk ){
+        int iCol;
+        iStart = i;
+        i++;
+        if( i>=nChunk ){
+          pCtx->eState = 2;
+        }else{
+          fts5FastGetVarint32(pChunk, i, iCol);
+          pCtx->eState = fts5IndexColsetTest(pCtx->pColset, iCol);
+          if( pCtx->eState ){
+            fts5BufferSafeAppendBlob(pCtx->pBuf, &pChunk[iStart], i-iStart);
+            iStart = i;
+          }
+        }
+      }
+    }while( i<nChunk );
+  }
+}
+
+static void fts5ChunkIterate(
+  Fts5Index *p,                   /* Index object */
+  Fts5SegIter *pSeg,              /* Poslist of this iterator */
+  void *pCtx,                     /* Context pointer for xChunk callback */
+  void (*xChunk)(Fts5Index*, void*, const u8*, int)
+){
+  int nRem = pSeg->nPos;          /* Number of bytes still to come */
+  Fts5Data *pData = 0;
+  u8 *pChunk = &pSeg->pLeaf->p[pSeg->iLeafOffset];
+  int nChunk = MIN(nRem, pSeg->pLeaf->szLeaf - pSeg->iLeafOffset);
+  int pgno = pSeg->iLeafPgno;
+  int pgnoSave = 0;
+
+  /* This function does not work with detail=none databases. */
+  assert( p->pConfig->eDetail!=FTS5_DETAIL_NONE );
+
+  if( (pSeg->flags & FTS5_SEGITER_REVERSE)==0 ){
+    pgnoSave = pgno+1;
+  }
+
+  while( 1 ){
+    xChunk(p, pCtx, pChunk, nChunk);
+    nRem -= nChunk;
+    fts5DataRelease(pData);
+    if( nRem<=0 ){
+      break;
+    }else if( pSeg->pSeg==0 ){
+      p->rc = FTS5_CORRUPT;
+      return;
+    }else{
+      pgno++;
+      pData = fts5LeafRead(p, FTS5_SEGMENT_ROWID(pSeg->pSeg->iSegid, pgno));
+      if( pData==0 ) break;
+      pChunk = &pData->p[4];
+      nChunk = MIN(nRem, pData->szLeaf - 4);
+      if( pgno==pgnoSave ){
+        assert( pSeg->pNextLeaf==0 );
+        pSeg->pNextLeaf = pData;
+        pData = 0;
+      }
+    }
+  }
+}
+
+/*
+** Iterator pIter currently points to a valid entry (not EOF). This
+** function appends the position list data for the current entry to
+** buffer pBuf. It does not make a copy of the position-list size
+** field.
+*/
+static void fts5SegiterPoslist(
+  Fts5Index *p,
+  Fts5SegIter *pSeg,
+  Fts5Colset *pColset,
+  Fts5Buffer *pBuf
+){
+  assert( pBuf!=0 );
+  assert( pSeg!=0 );
+  if( 0==fts5BufferGrow(&p->rc, pBuf, pSeg->nPos+FTS5_DATA_ZERO_PADDING) ){
+    assert( pBuf->p!=0 );
+    assert( pBuf->nSpace >= pBuf->n+pSeg->nPos+FTS5_DATA_ZERO_PADDING );
+    memset(&pBuf->p[pBuf->n+pSeg->nPos], 0, FTS5_DATA_ZERO_PADDING);
+    if( pColset==0 ){
+      fts5ChunkIterate(p, pSeg, (void*)pBuf, fts5PoslistCallback);
+    }else{
+      if( p->pConfig->eDetail==FTS5_DETAIL_FULL ){
+        PoslistCallbackCtx sCtx;
+        sCtx.pBuf = pBuf;
+        sCtx.pColset = pColset;
+        sCtx.eState = fts5IndexColsetTest(pColset, 0);
+        assert( sCtx.eState==0 || sCtx.eState==1 );
+        fts5ChunkIterate(p, pSeg, (void*)&sCtx, fts5PoslistFilterCallback);
+      }else{
+        PoslistOffsetsCtx sCtx;
+        memset(&sCtx, 0, sizeof(sCtx));
+        sCtx.pBuf = pBuf;
+        sCtx.pColset = pColset;
+        fts5ChunkIterate(p, pSeg, (void*)&sCtx, fts5PoslistOffsetsCallback);
+      }
+    }
+  }
+}
+
+/*
+** Parameter pPos points to a buffer containing a position list, size nPos.
+** This function filters it according to pColset (which must be non-NULL)
+** and sets pIter->base.pData/nData to point to the new position list.
+** If memory is required for the new position list, use buffer pIter->poslist.
+** Or, if the new position list is a contiguous subset of the input, set
+** pIter->base.pData/nData to point directly to it.
+**
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. If an OOM error is encountered, *pRc is set to SQLITE_NOMEM
+** before returning.
+*/
+static void fts5IndexExtractColset(
+  int *pRc,
+  Fts5Colset *pColset,            /* Colset to filter on */
+  const u8 *pPos, int nPos,       /* Position list */
+  Fts5Iter *pIter
+){
+  if( *pRc==SQLITE_OK ){
+    const u8 *p = pPos;
+    const u8 *aCopy = p;
+    const u8 *pEnd = &p[nPos];    /* One byte past end of position list */
+    int i = 0;
+    int iCurrent = 0;
+
+    if( pColset->nCol>1 && sqlite3Fts5BufferSize(pRc, &pIter->poslist, nPos) ){
+      return;
+    }
+
+    while( 1 ){
+      while( pColset->aiCol[i]<iCurrent ){
+        i++;
+        if( i==pColset->nCol ){
+          pIter->base.pData = pIter->poslist.p;
+          pIter->base.nData = pIter->poslist.n;
+          return;
+        }
+      }
+
+      /* Advance pointer p until it points to pEnd or an 0x01 byte that is
+      ** not part of a varint */
+      while( p<pEnd && *p!=0x01 ){
+        while( *p++ & 0x80 );
+      }
+
+      if( pColset->aiCol[i]==iCurrent ){
+        if( pColset->nCol==1 ){
+          pIter->base.pData = aCopy;
+          pIter->base.nData = p-aCopy;
+          return;
+        }
+        fts5BufferSafeAppendBlob(&pIter->poslist, aCopy, p-aCopy);
+      }
+      if( p>=pEnd ){
+        pIter->base.pData = pIter->poslist.p;
+        pIter->base.nData = pIter->poslist.n;
+        return;
+      }
+      aCopy = p++;
+      iCurrent = *p++;
+      if( iCurrent & 0x80 ){
+        p--;
+        p += fts5GetVarint32(p, iCurrent);
+      }
+    }
+  }
+
+}
+
+/*
+** xSetOutputs callback used by detail=none tables.
+*/
+static void fts5IterSetOutputs_None(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  assert( pIter->pIndex->pConfig->eDetail==FTS5_DETAIL_NONE );
+  pIter->base.iRowid = pSeg->iRowid;
+  pIter->base.nData = pSeg->nPos;
+}
+
+/*
+** xSetOutputs callback used by detail=full and detail=col tables when no
+** column filters are specified.
+*/
+static void fts5IterSetOutputs_Nocolset(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  pIter->base.iRowid = pSeg->iRowid;
+  pIter->base.nData = pSeg->nPos;
+
+  assert( pIter->pIndex->pConfig->eDetail!=FTS5_DETAIL_NONE );
+  assert( pIter->pColset==0 );
+
+  if( pSeg->iLeafOffset+pSeg->nPos<=pSeg->pLeaf->szLeaf ){
+    /* All data is stored on the current page. Populate the output
+    ** variables to point into the body of the page object. */
+    pIter->base.pData = &pSeg->pLeaf->p[pSeg->iLeafOffset];
+  }else{
+    /* The data is distributed over two or more pages. Copy it into the
+    ** Fts5Iter.poslist buffer and then set the output pointer to point
+    ** to this buffer.  */
+    fts5BufferZero(&pIter->poslist);
+    fts5SegiterPoslist(pIter->pIndex, pSeg, 0, &pIter->poslist);
+    pIter->base.pData = pIter->poslist.p;
+  }
+}
+
+/*
+** xSetOutputs callback used when the Fts5Colset object has nCol==0 (match
+** against no columns at all).
+*/
+static void fts5IterSetOutputs_ZeroColset(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  UNUSED_PARAM(pSeg);
+  pIter->base.nData = 0;
+}
+
+/*
+** xSetOutputs callback used by detail=col when there is a column filter
+** and there are 100 or more columns. Also called as a fallback from
+** fts5IterSetOutputs_Col100 if the column-list spans more than one page.
+*/
+static void fts5IterSetOutputs_Col(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  fts5BufferZero(&pIter->poslist);
+  fts5SegiterPoslist(pIter->pIndex, pSeg, pIter->pColset, &pIter->poslist);
+  pIter->base.iRowid = pSeg->iRowid;
+  pIter->base.pData = pIter->poslist.p;
+  pIter->base.nData = pIter->poslist.n;
+}
+
+/*
+** xSetOutputs callback used when:
+**
+**   * detail=col,
+**   * there is a column filter, and
+**   * the table contains 100 or fewer columns.
+**
+** The last point is to ensure all column numbers are stored as
+** single-byte varints.
+*/
+static void fts5IterSetOutputs_Col100(Fts5Iter *pIter, Fts5SegIter *pSeg){
+
+  assert( pIter->pIndex->pConfig->eDetail==FTS5_DETAIL_COLUMNS );
+  assert( pIter->pColset );
+
+  if( pSeg->iLeafOffset+pSeg->nPos>pSeg->pLeaf->szLeaf ){
+    fts5IterSetOutputs_Col(pIter, pSeg);
+  }else{
+    u8 *a = (u8*)&pSeg->pLeaf->p[pSeg->iLeafOffset];
+    u8 *pEnd = (u8*)&a[pSeg->nPos];
+    int iPrev = 0;
+    int *aiCol = pIter->pColset->aiCol;
+    int *aiColEnd = &aiCol[pIter->pColset->nCol];
+
+    u8 *aOut = pIter->poslist.p;
+    int iPrevOut = 0;
+
+    pIter->base.iRowid = pSeg->iRowid;
+
+    while( a<pEnd ){
+      iPrev += (int)a++[0] - 2;
+      while( *aiCol<iPrev ){
+        aiCol++;
+        if( aiCol==aiColEnd ) goto setoutputs_col_out;
+      }
+      if( *aiCol==iPrev ){
+        *aOut++ = (u8)((iPrev - iPrevOut) + 2);
+        iPrevOut = iPrev;
+      }
+    }
+
+setoutputs_col_out:
+    pIter->base.pData = pIter->poslist.p;
+    pIter->base.nData = aOut - pIter->poslist.p;
+  }
+}
+
+/*
+** xSetOutputs callback used by detail=full when there is a column filter.
+*/
+static void fts5IterSetOutputs_Full(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  Fts5Colset *pColset = pIter->pColset;
+  pIter->base.iRowid = pSeg->iRowid;
+
+  assert( pIter->pIndex->pConfig->eDetail==FTS5_DETAIL_FULL );
+  assert( pColset );
+
+  if( pSeg->iLeafOffset+pSeg->nPos<=pSeg->pLeaf->szLeaf ){
+    /* All data is stored on the current page. Populate the output
+    ** variables to point into the body of the page object. */
+    const u8 *a = &pSeg->pLeaf->p[pSeg->iLeafOffset];
+    int *pRc = &pIter->pIndex->rc;
+    fts5BufferZero(&pIter->poslist);
+    fts5IndexExtractColset(pRc, pColset, a, pSeg->nPos, pIter);
+  }else{
+    /* The data is distributed over two or more pages. Copy it into the
+    ** Fts5Iter.poslist buffer and then set the output pointer to point
+    ** to this buffer.  */
+    fts5BufferZero(&pIter->poslist);
+    fts5SegiterPoslist(pIter->pIndex, pSeg, pColset, &pIter->poslist);
+    pIter->base.pData = pIter->poslist.p;
+    pIter->base.nData = pIter->poslist.n;
+  }
+}
+
+static void fts5IterSetOutputCb(int *pRc, Fts5Iter *pIter){
+  assert( pIter!=0 || (*pRc)!=SQLITE_OK );
+  if( *pRc==SQLITE_OK ){
+    Fts5Config *pConfig = pIter->pIndex->pConfig;
+    if( pConfig->eDetail==FTS5_DETAIL_NONE ){
+      pIter->xSetOutputs = fts5IterSetOutputs_None;
+    }
+
+    else if( pIter->pColset==0 ){
+      pIter->xSetOutputs = fts5IterSetOutputs_Nocolset;
+    }
+
+    else if( pIter->pColset->nCol==0 ){
+      pIter->xSetOutputs = fts5IterSetOutputs_ZeroColset;
+    }
+
+    else if( pConfig->eDetail==FTS5_DETAIL_FULL ){
+      pIter->xSetOutputs = fts5IterSetOutputs_Full;
+    }
+
+    else{
+      assert( pConfig->eDetail==FTS5_DETAIL_COLUMNS );
+      if( pConfig->nCol<=100 ){
+        pIter->xSetOutputs = fts5IterSetOutputs_Col100;
+        sqlite3Fts5BufferSize(pRc, &pIter->poslist, pConfig->nCol);
+      }else{
+        pIter->xSetOutputs = fts5IterSetOutputs_Col;
+      }
+    }
+  }
+}
+
+/*
+** All the component segment-iterators of pIter have been set up. This
+** functions finishes setup for iterator pIter itself.
+*/
+static void fts5MultiIterFinishSetup(Fts5Index *p, Fts5Iter *pIter){
+  int iIter;
+  for(iIter=pIter->nSeg-1; iIter>0; iIter--){
+    int iEq;
+    if( (iEq = fts5MultiIterDoCompare(pIter, iIter)) ){
+      Fts5SegIter *pSeg = &pIter->aSeg[iEq];
+      if( p->rc==SQLITE_OK ) pSeg->xNext(p, pSeg, 0);
+      fts5MultiIterAdvanced(p, pIter, iEq, iIter);
+    }
+  }
+  fts5MultiIterSetEof(pIter);
+  fts5AssertMultiIterSetup(p, pIter);
+
+  if( (pIter->bSkipEmpty && fts5MultiIterIsEmpty(p, pIter))
+   || fts5MultiIterIsDeleted(pIter)
+  ){
+    fts5MultiIterNext(p, pIter, 0, 0);
+  }else if( pIter->base.bEof==0 ){
+    Fts5SegIter *pSeg = &pIter->aSeg[pIter->aFirst[1].iFirst];
+    pIter->xSetOutputs(pIter, pSeg);
+  }
+}
+
+/*
+** Allocate a new Fts5Iter object.
+**
+** The new object will be used to iterate through data in structure pStruct.
+** If iLevel is -ve, then all data in all segments is merged. Or, if iLevel
+** is zero or greater, data from the first nSegment segments on level iLevel
+** is merged.
+**
+** The iterator initially points to the first term/rowid entry in the
+** iterated data.
+*/
+static void fts5MultiIterNew(
+  Fts5Index *p,                   /* FTS5 backend to iterate within */
+  Fts5Structure *pStruct,         /* Structure of specific index */
+  int flags,                      /* FTS5INDEX_QUERY_XXX flags */
+  Fts5Colset *pColset,            /* Colset to filter on (or NULL) */
+  const u8 *pTerm, int nTerm,     /* Term to seek to (or NULL/0) */
+  int iLevel,                     /* Level to iterate (-1 for all) */
+  int nSegment,                   /* Number of segments to merge (iLevel>=0) */
+  Fts5Iter **ppOut                /* New object */
+){
+  int nSeg = 0;                   /* Number of segment-iters in use */
+  int iIter = 0;                  /* */
+  int iSeg;                       /* Used to iterate through segments */
+  Fts5StructureLevel *pLvl;
+  Fts5Iter *pNew;
+
+  assert( (pTerm==0 && nTerm==0) || iLevel<0 );
+
+  /* Allocate space for the new multi-seg-iterator. */
+  if( p->rc==SQLITE_OK ){
+    if( iLevel<0 ){
+      assert( pStruct->nSegment==fts5StructureCountSegments(pStruct) );
+      nSeg = pStruct->nSegment;
+      nSeg += (p->pHash && 0==(flags & FTS5INDEX_QUERY_SKIPHASH));
+    }else{
+      nSeg = MIN(pStruct->aLevel[iLevel].nSeg, nSegment);
+    }
+  }
+  *ppOut = pNew = fts5MultiIterAlloc(p, nSeg);
+  if( pNew==0 ){
+    assert( p->rc!=SQLITE_OK );
+    goto fts5MultiIterNew_post_check;
+  }
+  pNew->bRev = (0!=(flags & FTS5INDEX_QUERY_DESC));
+  pNew->bSkipEmpty = (0!=(flags & FTS5INDEX_QUERY_SKIPEMPTY));
+  pNew->pColset = pColset;
+  if( (flags & FTS5INDEX_QUERY_NOOUTPUT)==0 ){
+    fts5IterSetOutputCb(&p->rc, pNew);
+  }
+
+  /* Initialize each of the component segment iterators. */
+  if( p->rc==SQLITE_OK ){
+    if( iLevel<0 ){
+      Fts5StructureLevel *pEnd = &pStruct->aLevel[pStruct->nLevel];
+      if( p->pHash && 0==(flags & FTS5INDEX_QUERY_SKIPHASH) ){
+        /* Add a segment iterator for the current contents of the hash table. */
+        Fts5SegIter *pIter = &pNew->aSeg[iIter++];
+        fts5SegIterHashInit(p, pTerm, nTerm, flags, pIter);
+      }
+      for(pLvl=&pStruct->aLevel[0]; pLvl<pEnd; pLvl++){
+        for(iSeg=pLvl->nSeg-1; iSeg>=0; iSeg--){
+          Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
+          Fts5SegIter *pIter = &pNew->aSeg[iIter++];
+          if( pTerm==0 ){
+            fts5SegIterInit(p, pSeg, pIter);
+          }else{
+            fts5SegIterSeekInit(p, pTerm, nTerm, flags, pSeg, pIter);
+          }
+        }
+      }
+    }else{
+      pLvl = &pStruct->aLevel[iLevel];
+      for(iSeg=nSeg-1; iSeg>=0; iSeg--){
+        fts5SegIterInit(p, &pLvl->aSeg[iSeg], &pNew->aSeg[iIter++]);
+      }
+    }
+    assert( iIter==nSeg );
+  }
+
+  /* If the above was successful, each component iterator now points
+  ** to the first entry in its segment. In this case initialize the
+  ** aFirst[] array. Or, if an error has occurred, free the iterator
+  ** object and set the output variable to NULL.  */
+  if( p->rc==SQLITE_OK ){
+    fts5MultiIterFinishSetup(p, pNew);
+  }else{
+    fts5MultiIterFree(pNew);
+    *ppOut = 0;
+  }
+
+fts5MultiIterNew_post_check:
+  assert( (*ppOut)!=0 || p->rc!=SQLITE_OK );
+  return;
+}
+
+/*
+** Create an Fts5Iter that iterates through the doclist provided
+** as the second argument.
+*/
+static void fts5MultiIterNew2(
+  Fts5Index *p,                   /* FTS5 backend to iterate within */
+  Fts5Data *pData,                /* Doclist to iterate through */
+  int bDesc,                      /* True for descending rowid order */
+  Fts5Iter **ppOut                /* New object */
+){
+  Fts5Iter *pNew;
+  pNew = fts5MultiIterAlloc(p, 2);
+  if( pNew ){
+    Fts5SegIter *pIter = &pNew->aSeg[1];
+    pIter->flags = FTS5_SEGITER_ONETERM;
+    if( pData->szLeaf>0 ){
+      pIter->pLeaf = pData;
+      pIter->iLeafOffset = fts5GetVarint(pData->p, (u64*)&pIter->iRowid);
+      pIter->iEndofDoclist = pData->nn;
+      pNew->aFirst[1].iFirst = 1;
+      if( bDesc ){
+        pNew->bRev = 1;
+        pIter->flags |= FTS5_SEGITER_REVERSE;
+        fts5SegIterReverseInitPage(p, pIter);
+      }else{
+        fts5SegIterLoadNPos(p, pIter);
+      }
+      pData = 0;
+    }else{
+      pNew->base.bEof = 1;
+    }
+    fts5SegIterSetNext(p, pIter);
+
+    *ppOut = pNew;
+  }
+
+  fts5DataRelease(pData);
+}
+
+/*
+** Return true if the iterator is at EOF or if an error has occurred.
+** False otherwise.
+*/
+static int fts5MultiIterEof(Fts5Index *p, Fts5Iter *pIter){
+  assert( pIter!=0 || p->rc!=SQLITE_OK );
+  assert( p->rc!=SQLITE_OK
+      || (pIter->aSeg[ pIter->aFirst[1].iFirst ].pLeaf==0)==pIter->base.bEof
+  );
+  return (p->rc || pIter->base.bEof);
+}
+
+/*
+** Return the rowid of the entry that the iterator currently points
+** to. If the iterator points to EOF when this function is called the
+** results are undefined.
+*/
+static i64 fts5MultiIterRowid(Fts5Iter *pIter){
+  assert( pIter->aSeg[ pIter->aFirst[1].iFirst ].pLeaf );
+  return pIter->aSeg[ pIter->aFirst[1].iFirst ].iRowid;
+}
+
+/*
+** Move the iterator to the next entry at or following iMatch.
+*/
+static void fts5MultiIterNextFrom(
+  Fts5Index *p,
+  Fts5Iter *pIter,
+  i64 iMatch
+){
+  while( 1 ){
+    i64 iRowid;
+    fts5MultiIterNext(p, pIter, 1, iMatch);
+    if( fts5MultiIterEof(p, pIter) ) break;
+    iRowid = fts5MultiIterRowid(pIter);
+    if( pIter->bRev==0 && iRowid>=iMatch ) break;
+    if( pIter->bRev!=0 && iRowid<=iMatch ) break;
+  }
+}
+
+/*
+** Return a pointer to a buffer containing the term associated with the
+** entry that the iterator currently points to.
+*/
+static const u8 *fts5MultiIterTerm(Fts5Iter *pIter, int *pn){
+  Fts5SegIter *p = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+  *pn = p->term.n;
+  return p->term.p;
+}
+
+/*
+** Allocate a new segment-id for the structure pStruct. The new segment
+** id must be between 1 and 65335 inclusive, and must not be used by
+** any currently existing segment. If a free segment id cannot be found,
+** SQLITE_FULL is returned.
+**
+** If an error has already occurred, this function is a no-op. 0 is
+** returned in this case.
+*/
+static int fts5AllocateSegid(Fts5Index *p, Fts5Structure *pStruct){
+  int iSegid = 0;
+
+  if( p->rc==SQLITE_OK ){
+    if( pStruct->nSegment>=FTS5_MAX_SEGMENT ){
+      p->rc = SQLITE_FULL;
+    }else{
+      /* FTS5_MAX_SEGMENT is currently defined as 2000. So the following
+      ** array is 63 elements, or 252 bytes, in size.  */
+      u32 aUsed[(FTS5_MAX_SEGMENT+31) / 32];
+      int iLvl, iSeg;
+      int i;
+      u32 mask;
+      memset(aUsed, 0, sizeof(aUsed));
+      for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+        for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
+          int iId = pStruct->aLevel[iLvl].aSeg[iSeg].iSegid;
+          if( iId<=FTS5_MAX_SEGMENT && iId>0 ){
+            aUsed[(iId-1) / 32] |= (u32)1 << ((iId-1) % 32);
+          }
+        }
+      }
+
+      for(i=0; aUsed[i]==0xFFFFFFFF; i++);
+      mask = aUsed[i];
+      for(iSegid=0; mask & ((u32)1 << iSegid); iSegid++);
+      iSegid += 1 + i*32;
+
+#ifdef SQLITE_DEBUG
+      for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+        for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
+          assert_nc( iSegid!=pStruct->aLevel[iLvl].aSeg[iSeg].iSegid );
+        }
+      }
+      assert_nc( iSegid>0 && iSegid<=FTS5_MAX_SEGMENT );
+
+      {
+        sqlite3_stmt *pIdxSelect = fts5IdxSelectStmt(p);
+        if( p->rc==SQLITE_OK ){
+          u8 aBlob[2] = {0xff, 0xff};
+          sqlite3_bind_int(pIdxSelect, 1, iSegid);
+          sqlite3_bind_blob(pIdxSelect, 2, aBlob, 2, SQLITE_STATIC);
+          assert_nc( sqlite3_step(pIdxSelect)!=SQLITE_ROW );
+          p->rc = sqlite3_reset(pIdxSelect);
+          sqlite3_bind_null(pIdxSelect, 2);
+        }
+      }
+#endif
+    }
+  }
+
+  return iSegid;
+}
+
+/*
+** Discard all data currently cached in the hash-tables.
+*/
+static void fts5IndexDiscardData(Fts5Index *p){
+  assert( p->pHash || p->nPendingData==0 );
+  if( p->pHash ){
+    sqlite3Fts5HashClear(p->pHash);
+    p->nPendingData = 0;
+    p->nPendingRow = 0;
+    p->flushRc = SQLITE_OK;
+  }
+  p->nContentlessDelete = 0;
+}
+
+/*
+** Return the size of the prefix, in bytes, that buffer
+** (pNew/<length-unknown>) shares with buffer (pOld/nOld).
+**
+** Buffer (pNew/<length-unknown>) is guaranteed to be greater
+** than buffer (pOld/nOld).
+*/
+static int fts5PrefixCompress(int nOld, const u8 *pOld, const u8 *pNew){
+  int i;
+  for(i=0; i<nOld; i++){
+    if( pOld[i]!=pNew[i] ) break;
+  }
+  return i;
+}
+
+static void fts5WriteDlidxClear(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  int bFlush                      /* If true, write dlidx to disk */
+){
+  int i;
+  assert( bFlush==0 || (pWriter->nDlidx>0 && pWriter->aDlidx[0].buf.n>0) );
+  for(i=0; i<pWriter->nDlidx; i++){
+    Fts5DlidxWriter *pDlidx = &pWriter->aDlidx[i];
+    if( pDlidx->buf.n==0 ) break;
+    if( bFlush ){
+      assert( pDlidx->pgno!=0 );
+      fts5DataWrite(p,
+          FTS5_DLIDX_ROWID(pWriter->iSegid, i, pDlidx->pgno),
+          pDlidx->buf.p, pDlidx->buf.n
+      );
+    }
+    sqlite3Fts5BufferZero(&pDlidx->buf);
+    pDlidx->bPrevValid = 0;
+  }
+}
+
+/*
+** Grow the pWriter->aDlidx[] array to at least nLvl elements in size.
+** Any new array elements are zeroed before returning.
+*/
+static int fts5WriteDlidxGrow(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  int nLvl
+){
+  if( p->rc==SQLITE_OK && nLvl>=pWriter->nDlidx ){
+    Fts5DlidxWriter *aDlidx = (Fts5DlidxWriter*)sqlite3_realloc64(
+        pWriter->aDlidx, sizeof(Fts5DlidxWriter) * nLvl
+    );
+    if( aDlidx==0 ){
+      p->rc = SQLITE_NOMEM;
+    }else{
+      size_t nByte = sizeof(Fts5DlidxWriter) * (nLvl - pWriter->nDlidx);
+      memset(&aDlidx[pWriter->nDlidx], 0, nByte);
+      pWriter->aDlidx = aDlidx;
+      pWriter->nDlidx = nLvl;
+    }
+  }
+  return p->rc;
+}
+
+/*
+** If the current doclist-index accumulating in pWriter->aDlidx[] is large
+** enough, flush it to disk and return 1. Otherwise discard it and return
+** zero.
+*/
+static int fts5WriteFlushDlidx(Fts5Index *p, Fts5SegWriter *pWriter){
+  int bFlag = 0;
+
+  /* If there were FTS5_MIN_DLIDX_SIZE or more empty leaf pages written
+  ** to the database, also write the doclist-index to disk.  */
+  if( pWriter->aDlidx[0].buf.n>0 && pWriter->nEmpty>=FTS5_MIN_DLIDX_SIZE ){
+    bFlag = 1;
+  }
+  fts5WriteDlidxClear(p, pWriter, bFlag);
+  pWriter->nEmpty = 0;
+  return bFlag;
+}
+
+/*
+** This function is called whenever processing of the doclist for the
+** last term on leaf page (pWriter->iBtPage) is completed.
+**
+** The doclist-index for that term is currently stored in-memory within the
+** Fts5SegWriter.aDlidx[] array. If it is large enough, this function
+** writes it out to disk. Or, if it is too small to bother with, discards
+** it.
+**
+** Fts5SegWriter.btterm currently contains the first term on page iBtPage.
+*/
+static void fts5WriteFlushBtree(Fts5Index *p, Fts5SegWriter *pWriter){
+  int bFlag;
+
+  assert( pWriter->iBtPage || pWriter->nEmpty==0 );
+  if( pWriter->iBtPage==0 ) return;
+  bFlag = fts5WriteFlushDlidx(p, pWriter);
+
+  if( p->rc==SQLITE_OK ){
+    const char *z = (pWriter->btterm.n>0?(const char*)pWriter->btterm.p:"");
+    /* The following was already done in fts5WriteInit(): */
+    /* sqlite3_bind_int(p->pIdxWriter, 1, pWriter->iSegid); */
+    sqlite3_bind_blob(p->pIdxWriter, 2, z, pWriter->btterm.n, SQLITE_STATIC);
+    sqlite3_bind_int64(p->pIdxWriter, 3, bFlag + ((i64)pWriter->iBtPage<<1));
+    sqlite3_step(p->pIdxWriter);
+    p->rc = sqlite3_reset(p->pIdxWriter);
+    sqlite3_bind_null(p->pIdxWriter, 2);
+  }
+  pWriter->iBtPage = 0;
+}
+
+/*
+** This is called once for each leaf page except the first that contains
+** at least one term. Argument (nTerm/pTerm) is the split-key - a term that
+** is larger than all terms written to earlier leaves, and equal to or
+** smaller than the first term on the new leaf.
+**
+** If an error occurs, an error code is left in Fts5Index.rc. If an error
+** has already occurred when this function is called, it is a no-op.
+*/
+static void fts5WriteBtreeTerm(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegWriter *pWriter,         /* Writer object */
+  int nTerm, const u8 *pTerm      /* First term on new page */
+){
+  fts5WriteFlushBtree(p, pWriter);
+  if( p->rc==SQLITE_OK ){
+    fts5BufferSet(&p->rc, &pWriter->btterm, nTerm, pTerm);
+    pWriter->iBtPage = pWriter->writer.pgno;
+  }
+}
+
+/*
+** This function is called when flushing a leaf page that contains no
+** terms at all to disk.
+*/
+static void fts5WriteBtreeNoTerm(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegWriter *pWriter          /* Writer object */
+){
+  /* If there were no rowids on the leaf page either and the doclist-index
+  ** has already been started, append an 0x00 byte to it.  */
+  if( pWriter->bFirstRowidInPage && pWriter->aDlidx[0].buf.n>0 ){
+    Fts5DlidxWriter *pDlidx = &pWriter->aDlidx[0];
+    assert( pDlidx->bPrevValid );
+    sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx->buf, 0);
+  }
+
+  /* Increment the "number of sequential leaves without a term" counter. */
+  pWriter->nEmpty++;
+}
+
+static i64 fts5DlidxExtractFirstRowid(Fts5Buffer *pBuf){
+  i64 iRowid;
+  int iOff;
+
+  iOff = 1 + fts5GetVarint(&pBuf->p[1], (u64*)&iRowid);
+  fts5GetVarint(&pBuf->p[iOff], (u64*)&iRowid);
+  return iRowid;
+}
+
+/*
+** Rowid iRowid has just been appended to the current leaf page. It is the
+** first on the page. This function appends an appropriate entry to the current
+** doclist-index.
+*/
+static void fts5WriteDlidxAppend(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  i64 iRowid
+){
+  int i;
+  int bDone = 0;
+
+  for(i=0; p->rc==SQLITE_OK && bDone==0; i++){
+    i64 iVal;
+    Fts5DlidxWriter *pDlidx = &pWriter->aDlidx[i];
+
+    if( pDlidx->buf.n>=p->pConfig->pgsz ){
+      /* The current doclist-index page is full. Write it to disk and push
+      ** a copy of iRowid (which will become the first rowid on the next
+      ** doclist-index leaf page) up into the next level of the b-tree
+      ** hierarchy. If the node being flushed is currently the root node,
+      ** also push its first rowid upwards. */
+      pDlidx->buf.p[0] = 0x01;    /* Not the root node */
+      fts5DataWrite(p,
+          FTS5_DLIDX_ROWID(pWriter->iSegid, i, pDlidx->pgno),
+          pDlidx->buf.p, pDlidx->buf.n
+      );
+      fts5WriteDlidxGrow(p, pWriter, i+2);
+      pDlidx = &pWriter->aDlidx[i];
+      if( p->rc==SQLITE_OK && pDlidx[1].buf.n==0 ){
+        i64 iFirst = fts5DlidxExtractFirstRowid(&pDlidx->buf);
+
+        /* This was the root node. Push its first rowid up to the new root. */
+        pDlidx[1].pgno = pDlidx->pgno;
+        sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx[1].buf, 0);
+        sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx[1].buf, pDlidx->pgno);
+        sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx[1].buf, iFirst);
+        pDlidx[1].bPrevValid = 1;
+        pDlidx[1].iPrev = iFirst;
+      }
+
+      sqlite3Fts5BufferZero(&pDlidx->buf);
+      pDlidx->bPrevValid = 0;
+      pDlidx->pgno++;
+    }else{
+      bDone = 1;
+    }
+
+    if( pDlidx->bPrevValid ){
+      iVal = (u64)iRowid - (u64)pDlidx->iPrev;
+    }else{
+      i64 iPgno = (i==0 ? pWriter->writer.pgno : pDlidx[-1].pgno);
+      assert( pDlidx->buf.n==0 );
+      sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx->buf, !bDone);
+      sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx->buf, iPgno);
+      iVal = iRowid;
+    }
+
+    sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx->buf, iVal);
+    pDlidx->bPrevValid = 1;
+    pDlidx->iPrev = iRowid;
+  }
+}
+
+static void fts5WriteFlushLeaf(Fts5Index *p, Fts5SegWriter *pWriter){
+  static const u8 zero[] = { 0x00, 0x00, 0x00, 0x00 };
+  Fts5PageWriter *pPage = &pWriter->writer;
+  i64 iRowid;
+
+  assert( (pPage->pgidx.n==0)==(pWriter->bFirstTermInPage) );
+
+  /* Set the szLeaf header field. */
+  assert( 0==fts5GetU16(&pPage->buf.p[2]) );
+  fts5PutU16(&pPage->buf.p[2], (u16)pPage->buf.n);
+
+  if( pWriter->bFirstTermInPage ){
+    /* No term was written to this page. */
+    assert( pPage->pgidx.n==0 );
+    fts5WriteBtreeNoTerm(p, pWriter);
+  }else{
+    /* Append the pgidx to the page buffer. Set the szLeaf header field. */
+    fts5BufferAppendBlob(&p->rc, &pPage->buf, pPage->pgidx.n, pPage->pgidx.p);
+  }
+
+  /* Write the page out to disk */
+  iRowid = FTS5_SEGMENT_ROWID(pWriter->iSegid, pPage->pgno);
+  fts5DataWrite(p, iRowid, pPage->buf.p, pPage->buf.n);
+
+  /* Initialize the next page. */
+  fts5BufferZero(&pPage->buf);
+  fts5BufferZero(&pPage->pgidx);
+  fts5BufferAppendBlob(&p->rc, &pPage->buf, 4, zero);
+  pPage->iPrevPgidx = 0;
+  pPage->pgno++;
+
+  /* Increase the leaves written counter */
+  pWriter->nLeafWritten++;
+
+  /* The new leaf holds no terms or rowids */
+  pWriter->bFirstTermInPage = 1;
+  pWriter->bFirstRowidInPage = 1;
+}
+
+/*
+** Append term pTerm/nTerm to the segment being written by the writer passed
+** as the second argument.
+**
+** If an error occurs, set the Fts5Index.rc error code. If an error has
+** already occurred, this function is a no-op.
+*/
+static void fts5WriteAppendTerm(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  int nTerm, const u8 *pTerm
+){
+  int nPrefix;                    /* Bytes of prefix compression for term */
+  Fts5PageWriter *pPage = &pWriter->writer;
+  Fts5Buffer *pPgidx = &pWriter->writer.pgidx;
+  int nMin = MIN(pPage->term.n, nTerm);
+
+  assert( p->rc==SQLITE_OK );
+  assert( pPage->buf.n>=4 );
+  assert( pPage->buf.n>4 || pWriter->bFirstTermInPage );
+
+  /* If the current leaf page is full, flush it to disk. */
+  if( (pPage->buf.n + pPgidx->n + nTerm + 2)>=p->pConfig->pgsz ){
+    if( pPage->buf.n>4 ){
+      fts5WriteFlushLeaf(p, pWriter);
+      if( p->rc!=SQLITE_OK ) return;
+    }
+    fts5BufferGrow(&p->rc, &pPage->buf, nTerm+FTS5_DATA_PADDING);
+  }
+
+  /* TODO1: Updating pgidx here. */
+  pPgidx->n += sqlite3Fts5PutVarint(
+      &pPgidx->p[pPgidx->n], pPage->buf.n - pPage->iPrevPgidx
+  );
+  pPage->iPrevPgidx = pPage->buf.n;
+#if 0
+  fts5PutU16(&pPgidx->p[pPgidx->n], pPage->buf.n);
+  pPgidx->n += 2;
+#endif
+
+  if( pWriter->bFirstTermInPage ){
+    nPrefix = 0;
+    if( pPage->pgno!=1 ){
+      /* This is the first term on a leaf that is not the leftmost leaf in
+      ** the segment b-tree. In this case it is necessary to add a term to
+      ** the b-tree hierarchy that is (a) larger than the largest term
+      ** already written to the segment and (b) smaller than or equal to
+      ** this term. In other words, a prefix of (pTerm/nTerm) that is one
+      ** byte longer than the longest prefix (pTerm/nTerm) shares with the
+      ** previous term.
+      **
+      ** Usually, the previous term is available in pPage->term. The exception
+      ** is if this is the first term written in an incremental-merge step.
+      ** In this case the previous term is not available, so just write a
+      ** copy of (pTerm/nTerm) into the parent node. This is slightly
+      ** inefficient, but still correct.  */
+      int n = nTerm;
+      if( pPage->term.n ){
+        n = 1 + fts5PrefixCompress(nMin, pPage->term.p, pTerm);
+      }
+      fts5WriteBtreeTerm(p, pWriter, n, pTerm);
+      if( p->rc!=SQLITE_OK ) return;
+      pPage = &pWriter->writer;
+    }
+  }else{
+    nPrefix = fts5PrefixCompress(nMin, pPage->term.p, pTerm);
+    fts5BufferAppendVarint(&p->rc, &pPage->buf, nPrefix);
+  }
+
+  /* Append the number of bytes of new data, then the term data itself
+  ** to the page. */
+  fts5BufferAppendVarint(&p->rc, &pPage->buf, nTerm - nPrefix);
+  fts5BufferAppendBlob(&p->rc, &pPage->buf, nTerm - nPrefix, &pTerm[nPrefix]);
+
+  /* Update the Fts5PageWriter.term field. */
+  fts5BufferSet(&p->rc, &pPage->term, nTerm, pTerm);
+  pWriter->bFirstTermInPage = 0;
+
+  pWriter->bFirstRowidInPage = 0;
+  pWriter->bFirstRowidInDoclist = 1;
+
+  assert( p->rc || (pWriter->nDlidx>0 && pWriter->aDlidx[0].buf.n==0) );
+  pWriter->aDlidx[0].pgno = pPage->pgno;
+}
+
+/*
+** Append a rowid and position-list size field to the writers output.
+*/
+static void fts5WriteAppendRowid(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  i64 iRowid
+){
+  if( p->rc==SQLITE_OK ){
+    Fts5PageWriter *pPage = &pWriter->writer;
+
+    if( (pPage->buf.n + pPage->pgidx.n)>=p->pConfig->pgsz ){
+      fts5WriteFlushLeaf(p, pWriter);
+    }
+
+    /* If this is to be the first rowid written to the page, set the
+    ** rowid-pointer in the page-header. Also append a value to the dlidx
+    ** buffer, in case a doclist-index is required.  */
+    if( pWriter->bFirstRowidInPage ){
+      fts5PutU16(pPage->buf.p, (u16)pPage->buf.n);
+      fts5WriteDlidxAppend(p, pWriter, iRowid);
+    }
+
+    /* Write the rowid. */
+    if( pWriter->bFirstRowidInDoclist || pWriter->bFirstRowidInPage ){
+      fts5BufferAppendVarint(&p->rc, &pPage->buf, iRowid);
+    }else{
+      assert_nc( p->rc || iRowid>pWriter->iPrevRowid );
+      fts5BufferAppendVarint(&p->rc, &pPage->buf,
+          (u64)iRowid - (u64)pWriter->iPrevRowid
+      );
+    }
+    pWriter->iPrevRowid = iRowid;
+    pWriter->bFirstRowidInDoclist = 0;
+    pWriter->bFirstRowidInPage = 0;
+  }
+}
+
+static void fts5WriteAppendPoslistData(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  const u8 *aData,
+  int nData
+){
+  Fts5PageWriter *pPage = &pWriter->writer;
+  const u8 *a = aData;
+  int n = nData;
+
+  assert( p->pConfig->pgsz>0 || p->rc!=SQLITE_OK );
+  while( p->rc==SQLITE_OK
+     && (pPage->buf.n + pPage->pgidx.n + n)>=p->pConfig->pgsz
+  ){
+    int nReq = p->pConfig->pgsz - pPage->buf.n - pPage->pgidx.n;
+    int nCopy = 0;
+    while( nCopy<nReq ){
+      i64 dummy;
+      nCopy += fts5GetVarint(&a[nCopy], (u64*)&dummy);
+    }
+    fts5BufferAppendBlob(&p->rc, &pPage->buf, nCopy, a);
+    a += nCopy;
+    n -= nCopy;
+    fts5WriteFlushLeaf(p, pWriter);
+  }
+  if( n>0 ){
+    fts5BufferAppendBlob(&p->rc, &pPage->buf, n, a);
+  }
+}
+
+/*
+** Flush any data cached by the writer object to the database. Free any
+** allocations associated with the writer.
+*/
+static void fts5WriteFinish(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,         /* Writer object */
+  int *pnLeaf                     /* OUT: Number of leaf pages in b-tree */
+){
+  int i;
+  Fts5PageWriter *pLeaf = &pWriter->writer;
+  if( p->rc==SQLITE_OK ){
+    assert( pLeaf->pgno>=1 );
+    if( pLeaf->buf.n>4 ){
+      fts5WriteFlushLeaf(p, pWriter);
+    }
+    *pnLeaf = pLeaf->pgno-1;
+    if( pLeaf->pgno>1 ){
+      fts5WriteFlushBtree(p, pWriter);
+    }
+  }
+  fts5BufferFree(&pLeaf->term);
+  fts5BufferFree(&pLeaf->buf);
+  fts5BufferFree(&pLeaf->pgidx);
+  fts5BufferFree(&pWriter->btterm);
+
+  for(i=0; i<pWriter->nDlidx; i++){
+    sqlite3Fts5BufferFree(&pWriter->aDlidx[i].buf);
+  }
+  sqlite3_free(pWriter->aDlidx);
+}
+
+static void fts5WriteInit(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  int iSegid
+){
+  const int nBuffer = p->pConfig->pgsz + FTS5_DATA_PADDING;
+
+  memset(pWriter, 0, sizeof(Fts5SegWriter));
+  pWriter->iSegid = iSegid;
+
+  fts5WriteDlidxGrow(p, pWriter, 1);
+  pWriter->writer.pgno = 1;
+  pWriter->bFirstTermInPage = 1;
+  pWriter->iBtPage = 1;
+
+  assert( pWriter->writer.buf.n==0 );
+  assert( pWriter->writer.pgidx.n==0 );
+
+  /* Grow the two buffers to pgsz + padding bytes in size. */
+  sqlite3Fts5BufferSize(&p->rc, &pWriter->writer.pgidx, nBuffer);
+  sqlite3Fts5BufferSize(&p->rc, &pWriter->writer.buf, nBuffer);
+
+  if( p->pIdxWriter==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pIdxWriter, sqlite3_mprintf(
+          "INSERT INTO '%q'.'%q_idx'(segid,term,pgno) VALUES(?,?,?)",
+          pConfig->zDb, pConfig->zName
+    ));
+  }
+
+  if( p->rc==SQLITE_OK ){
+    /* Initialize the 4-byte leaf-page header to 0x00. */
+    memset(pWriter->writer.buf.p, 0, 4);
+    pWriter->writer.buf.n = 4;
+
+    /* Bind the current output segment id to the index-writer. This is an
+    ** optimization over binding the same value over and over as rows are
+    ** inserted into %_idx by the current writer.  */
+    sqlite3_bind_int(p->pIdxWriter, 1, pWriter->iSegid);
+  }
+}
+
+/*
+** Iterator pIter was used to iterate through the input segments of on an
+** incremental merge operation. This function is called if the incremental
+** merge step has finished but the input has not been completely exhausted.
+*/
+static void fts5TrimSegments(Fts5Index *p, Fts5Iter *pIter){
+  int i;
+  Fts5Buffer buf;
+  memset(&buf, 0, sizeof(Fts5Buffer));
+  for(i=0; i<pIter->nSeg && p->rc==SQLITE_OK; i++){
+    Fts5SegIter *pSeg = &pIter->aSeg[i];
+    if( pSeg->pSeg==0 ){
+      /* no-op */
+    }else if( pSeg->pLeaf==0 ){
+      /* All keys from this input segment have been transfered to the output.
+      ** Set both the first and last page-numbers to 0 to indicate that the
+      ** segment is now empty. */
+      pSeg->pSeg->pgnoLast = 0;
+      pSeg->pSeg->pgnoFirst = 0;
+    }else{
+      int iOff = pSeg->iTermLeafOffset;     /* Offset on new first leaf page */
+      i64 iLeafRowid;
+      Fts5Data *pData;
+      int iId = pSeg->pSeg->iSegid;
+      u8 aHdr[4] = {0x00, 0x00, 0x00, 0x00};
+
+      iLeafRowid = FTS5_SEGMENT_ROWID(iId, pSeg->iTermLeafPgno);
+      pData = fts5LeafRead(p, iLeafRowid);
+      if( pData ){
+        if( iOff>pData->szLeaf ){
+          /* This can occur if the pages that the segments occupy overlap - if
+          ** a single page has been assigned to more than one segment. In
+          ** this case a prior iteration of this loop may have corrupted the
+          ** segment currently being trimmed.  */
+          p->rc = FTS5_CORRUPT;
+        }else{
+          fts5BufferZero(&buf);
+          fts5BufferGrow(&p->rc, &buf, pData->nn);
+          fts5BufferAppendBlob(&p->rc, &buf, sizeof(aHdr), aHdr);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->term.n);
+          fts5BufferAppendBlob(&p->rc, &buf, pSeg->term.n, pSeg->term.p);
+          fts5BufferAppendBlob(&p->rc, &buf,pData->szLeaf-iOff,&pData->p[iOff]);
+          if( p->rc==SQLITE_OK ){
+            /* Set the szLeaf field */
+            fts5PutU16(&buf.p[2], (u16)buf.n);
+          }
+
+          /* Set up the new page-index array */
+          fts5BufferAppendVarint(&p->rc, &buf, 4);
+          if( pSeg->iLeafPgno==pSeg->iTermLeafPgno
+           && pSeg->iEndofDoclist<pData->szLeaf
+           && pSeg->iPgidxOff<=pData->nn
+          ){
+            int nDiff = pData->szLeaf - pSeg->iEndofDoclist;
+            fts5BufferAppendVarint(&p->rc, &buf, buf.n - 1 - nDiff - 4);
+            fts5BufferAppendBlob(&p->rc, &buf,
+                pData->nn - pSeg->iPgidxOff, &pData->p[pSeg->iPgidxOff]
+            );
+          }
+
+          pSeg->pSeg->pgnoFirst = pSeg->iTermLeafPgno;
+          fts5DataDelete(p, FTS5_SEGMENT_ROWID(iId, 1), iLeafRowid);
+          fts5DataWrite(p, iLeafRowid, buf.p, buf.n);
+        }
+        fts5DataRelease(pData);
+      }
+    }
+  }
+  fts5BufferFree(&buf);
+}
+
+static void fts5MergeChunkCallback(
+  Fts5Index *p,
+  void *pCtx,
+  const u8 *pChunk, int nChunk
+){
+  Fts5SegWriter *pWriter = (Fts5SegWriter*)pCtx;
+  fts5WriteAppendPoslistData(p, pWriter, pChunk, nChunk);
+}
+
+/*
+**
+*/
+static void fts5IndexMergeLevel(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Structure **ppStruct,       /* IN/OUT: Stucture of index */
+  int iLvl,                       /* Level to read input from */
+  int *pnRem                      /* Write up to this many output leaves */
+){
+  Fts5Structure *pStruct = *ppStruct;
+  Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
+  Fts5StructureLevel *pLvlOut;
+  Fts5Iter *pIter = 0;       /* Iterator to read input data */
+  int nRem = pnRem ? *pnRem : 0;  /* Output leaf pages left to write */
+  int nInput;                     /* Number of input segments */
+  Fts5SegWriter writer;           /* Writer object */
+  Fts5StructureSegment *pSeg;     /* Output segment */
+  Fts5Buffer term;
+  int bOldest;                    /* True if the output segment is the oldest */
+  int eDetail = p->pConfig->eDetail;
+  const int flags = FTS5INDEX_QUERY_NOOUTPUT;
+  int bTermWritten = 0;           /* True if current term already output */
+
+  assert( iLvl<pStruct->nLevel );
+  assert( pLvl->nMerge<=pLvl->nSeg );
+
+  memset(&writer, 0, sizeof(Fts5SegWriter));
+  memset(&term, 0, sizeof(Fts5Buffer));
+  if( pLvl->nMerge ){
+    pLvlOut = &pStruct->aLevel[iLvl+1];
+    assert( pLvlOut->nSeg>0 );
+    nInput = pLvl->nMerge;
+    pSeg = &pLvlOut->aSeg[pLvlOut->nSeg-1];
+
+    fts5WriteInit(p, &writer, pSeg->iSegid);
+    writer.writer.pgno = pSeg->pgnoLast+1;
+    writer.iBtPage = 0;
+  }else{
+    int iSegid = fts5AllocateSegid(p, pStruct);
+
+    /* Extend the Fts5Structure object as required to ensure the output
+    ** segment exists. */
+    if( iLvl==pStruct->nLevel-1 ){
+      fts5StructureAddLevel(&p->rc, ppStruct);
+      pStruct = *ppStruct;
+    }
+    fts5StructureExtendLevel(&p->rc, pStruct, iLvl+1, 1, 0);
+    if( p->rc ) return;
+    pLvl = &pStruct->aLevel[iLvl];
+    pLvlOut = &pStruct->aLevel[iLvl+1];
+
+    fts5WriteInit(p, &writer, iSegid);
+
+    /* Add the new segment to the output level */
+    pSeg = &pLvlOut->aSeg[pLvlOut->nSeg];
+    pLvlOut->nSeg++;
+    pSeg->pgnoFirst = 1;
+    pSeg->iSegid = iSegid;
+    pStruct->nSegment++;
+
+    /* Read input from all segments in the input level */
+    nInput = pLvl->nSeg;
+
+    /* Set the range of origins that will go into the output segment. */
+    if( pStruct->nOriginCntr>0 ){
+      pSeg->iOrigin1 = pLvl->aSeg[0].iOrigin1;
+      pSeg->iOrigin2 = pLvl->aSeg[pLvl->nSeg-1].iOrigin2;
+    }
+  }
+  bOldest = (pLvlOut->nSeg==1 && pStruct->nLevel==iLvl+2);
+
+  assert( iLvl>=0 );
+  for(fts5MultiIterNew(p, pStruct, flags, 0, 0, 0, iLvl, nInput, &pIter);
+      fts5MultiIterEof(p, pIter)==0;
+      fts5MultiIterNext(p, pIter, 0, 0)
+  ){
+    Fts5SegIter *pSegIter = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+    int nPos;                     /* position-list size field value */
+    int nTerm;
+    const u8 *pTerm;
+
+    pTerm = fts5MultiIterTerm(pIter, &nTerm);
+    if( nTerm!=term.n || fts5Memcmp(pTerm, term.p, nTerm) ){
+      if( pnRem && writer.nLeafWritten>nRem ){
+        break;
+      }
+      fts5BufferSet(&p->rc, &term, nTerm, pTerm);
+      bTermWritten =0;
+    }
+
+    /* Check for key annihilation. */
+    if( pSegIter->nPos==0 && (bOldest || pSegIter->bDel==0) ) continue;
+
+    if( p->rc==SQLITE_OK && bTermWritten==0 ){
+      /* This is a new term. Append a term to the output segment. */
+      fts5WriteAppendTerm(p, &writer, nTerm, pTerm);
+      bTermWritten = 1;
+    }
+
+    /* Append the rowid to the output */
+    /* WRITEPOSLISTSIZE */
+    fts5WriteAppendRowid(p, &writer, fts5MultiIterRowid(pIter));
+
+    if( eDetail==FTS5_DETAIL_NONE ){
+      if( pSegIter->bDel ){
+        fts5BufferAppendVarint(&p->rc, &writer.writer.buf, 0);
+        if( pSegIter->nPos>0 ){
+          fts5BufferAppendVarint(&p->rc, &writer.writer.buf, 0);
+        }
+      }
+    }else{
+      /* Append the position-list data to the output */
+      nPos = pSegIter->nPos*2 + pSegIter->bDel;
+      fts5BufferAppendVarint(&p->rc, &writer.writer.buf, nPos);
+      fts5ChunkIterate(p, pSegIter, (void*)&writer, fts5MergeChunkCallback);
+    }
+  }
+
+  /* Flush the last leaf page to disk. Set the output segment b-tree height
+  ** and last leaf page number at the same time.  */
+  fts5WriteFinish(p, &writer, &pSeg->pgnoLast);
+
+  assert( pIter!=0 || p->rc!=SQLITE_OK );
+  if( fts5MultiIterEof(p, pIter) ){
+    int i;
+
+    /* Remove the redundant segments from the %_data table */
+    assert( pSeg->nEntry==0 );
+    for(i=0; i<nInput; i++){
+      Fts5StructureSegment *pOld = &pLvl->aSeg[i];
+      pSeg->nEntry += (pOld->nEntry - pOld->nEntryTombstone);
+      fts5DataRemoveSegment(p, pOld);
+    }
+
+    /* Remove the redundant segments from the input level */
+    if( pLvl->nSeg!=nInput ){
+      int nMove = (pLvl->nSeg - nInput) * sizeof(Fts5StructureSegment);
+      memmove(pLvl->aSeg, &pLvl->aSeg[nInput], nMove);
+    }
+    pStruct->nSegment -= nInput;
+    pLvl->nSeg -= nInput;
+    pLvl->nMerge = 0;
+    if( pSeg->pgnoLast==0 ){
+      pLvlOut->nSeg--;
+      pStruct->nSegment--;
+    }
+  }else{
+    assert( pSeg->pgnoLast>0 );
+    fts5TrimSegments(p, pIter);
+    pLvl->nMerge = nInput;
+  }
+
+  fts5MultiIterFree(pIter);
+  fts5BufferFree(&term);
+  if( pnRem ) *pnRem -= writer.nLeafWritten;
+}
+
+/*
+** If this is not a contentless_delete=1 table, or if the 'deletemerge'
+** configuration option is set to 0, then this function always returns -1.
+** Otherwise, it searches the structure object passed as the second argument
+** for a level suitable for merging due to having a large number of
+** tombstones in the tombstone hash. If one is found, its index is returned.
+** Otherwise, if there is no suitable level, -1.
+*/
+static int fts5IndexFindDeleteMerge(Fts5Index *p, Fts5Structure *pStruct){
+  Fts5Config *pConfig = p->pConfig;
+  int iRet = -1;
+  if( pConfig->bContentlessDelete && pConfig->nDeleteMerge>0 ){
+    int ii;
+    int nBest = 0;
+
+    for(ii=0; ii<pStruct->nLevel; ii++){
+      Fts5StructureLevel *pLvl = &pStruct->aLevel[ii];
+      i64 nEntry = 0;
+      i64 nTomb = 0;
+      int iSeg;
+      for(iSeg=0; iSeg<pLvl->nSeg; iSeg++){
+        nEntry += pLvl->aSeg[iSeg].nEntry;
+        nTomb += pLvl->aSeg[iSeg].nEntryTombstone;
+      }
+      assert_nc( nEntry>0 || pLvl->nSeg==0 );
+      if( nEntry>0 ){
+        int nPercent = (nTomb * 100) / nEntry;
+        if( nPercent>=pConfig->nDeleteMerge && nPercent>nBest ){
+          iRet = ii;
+          nBest = nPercent;
+        }
+      }
+
+      /* If pLvl is already the input level to an ongoing merge, look no
+      ** further for a merge candidate. The caller should be allowed to
+      ** continue merging from pLvl first.  */
+      if( pLvl->nMerge ) break;
+    }
+  }
+  return iRet;
+}
+
+/*
+** Do up to nPg pages of automerge work on the index.
+**
+** Return true if any changes were actually made, or false otherwise.
+*/
+static int fts5IndexMerge(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Structure **ppStruct,       /* IN/OUT: Current structure of index */
+  int nPg,                        /* Pages of work to do */
+  int nMin                        /* Minimum number of segments to merge */
+){
+  int nRem = nPg;
+  int bRet = 0;
+  Fts5Structure *pStruct = *ppStruct;
+  while( nRem>0 && p->rc==SQLITE_OK ){
+    int iLvl;                   /* To iterate through levels */
+    int iBestLvl = 0;           /* Level offering the most input segments */
+    int nBest = 0;              /* Number of input segments on best level */
+
+    /* Set iBestLvl to the level to read input segments from. Or to -1 if
+    ** there is no level suitable to merge segments from.  */
+    assert( pStruct->nLevel>0 );
+    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+      Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
+      if( pLvl->nMerge ){
+        if( pLvl->nMerge>nBest ){
+          iBestLvl = iLvl;
+          nBest = nMin;
+        }
+        break;
+      }
+      if( pLvl->nSeg>nBest ){
+        nBest = pLvl->nSeg;
+        iBestLvl = iLvl;
+      }
+    }
+    if( nBest<nMin ){
+      iBestLvl = fts5IndexFindDeleteMerge(p, pStruct);
+    }
+
+    if( iBestLvl<0 ) break;
+    bRet = 1;
+    fts5IndexMergeLevel(p, &pStruct, iBestLvl, &nRem);
+    if( p->rc==SQLITE_OK && pStruct->aLevel[iBestLvl].nMerge==0 ){
+      fts5StructurePromote(p, iBestLvl+1, pStruct);
+    }
+
+    if( nMin==1 ) nMin = 2;
+  }
+  *ppStruct = pStruct;
+  return bRet;
+}
+
+/*
+** A total of nLeaf leaf pages of data has just been flushed to a level-0
+** segment. This function updates the write-counter accordingly and, if
+** necessary, performs incremental merge work.
+**
+** If an error occurs, set the Fts5Index.rc error code. If an error has
+** already occurred, this function is a no-op.
+*/
+static void fts5IndexAutomerge(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Structure **ppStruct,       /* IN/OUT: Current structure of index */
+  int nLeaf                       /* Number of output leaves just written */
+){
+  if( p->rc==SQLITE_OK && p->pConfig->nAutomerge>0 && ALWAYS((*ppStruct)!=0) ){
+    Fts5Structure *pStruct = *ppStruct;
+    u64 nWrite;                   /* Initial value of write-counter */
+    int nWork;                    /* Number of work-quanta to perform */
+    int nRem;                     /* Number of leaf pages left to write */
+
+    /* Update the write-counter. While doing so, set nWork. */
+    nWrite = pStruct->nWriteCounter;
+    nWork = (int)(((nWrite + nLeaf) / p->nWorkUnit) - (nWrite / p->nWorkUnit));
+    pStruct->nWriteCounter += nLeaf;
+    nRem = (int)(p->nWorkUnit * nWork * pStruct->nLevel);
+
+    fts5IndexMerge(p, ppStruct, nRem, p->pConfig->nAutomerge);
+  }
+}
+
+static void fts5IndexCrisismerge(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Structure **ppStruct        /* IN/OUT: Current structure of index */
+){
+  const int nCrisis = p->pConfig->nCrisisMerge;
+  Fts5Structure *pStruct = *ppStruct;
+  if( pStruct && pStruct->nLevel>0 ){
+    int iLvl = 0;
+    while( p->rc==SQLITE_OK && pStruct->aLevel[iLvl].nSeg>=nCrisis ){
+      fts5IndexMergeLevel(p, &pStruct, iLvl, 0);
+      assert( p->rc!=SQLITE_OK || pStruct->nLevel>(iLvl+1) );
+      fts5StructurePromote(p, iLvl+1, pStruct);
+      iLvl++;
+    }
+    *ppStruct = pStruct;
+  }
+}
+
+static int fts5IndexReturn(Fts5Index *p){
+  int rc = p->rc;
+  p->rc = SQLITE_OK;
+  return rc;
+}
+
+/*
+** Close the read-only blob handle, if it is open.
+*/
+static void sqlite3Fts5IndexCloseReader(Fts5Index *p){
+  fts5IndexCloseReader(p);
+  fts5IndexReturn(p);
+}
+
+typedef struct Fts5FlushCtx Fts5FlushCtx;
+struct Fts5FlushCtx {
+  Fts5Index *pIdx;
+  Fts5SegWriter writer;
+};
+
+/*
+** Buffer aBuf[] contains a list of varints, all small enough to fit
+** in a 32-bit integer. Return the size of the largest prefix of this
+** list nMax bytes or less in size.
+*/
+static int fts5PoslistPrefix(const u8 *aBuf, int nMax){
+  int ret;
+  u32 dummy;
+  ret = fts5GetVarint32(aBuf, dummy);
+  if( ret<nMax ){
+    while( 1 ){
+      int i = fts5GetVarint32(&aBuf[ret], dummy);
+      if( (ret + i) > nMax ) break;
+      ret += i;
+    }
+  }
+  return ret;
+}
+
+/*
+** Execute the SQL statement:
+**
+**    DELETE FROM %_idx WHERE (segid, (pgno/2)) = ($iSegid, $iPgno);
+**
+** This is used when a secure-delete operation removes the last term
+** from a segment leaf page. In that case the %_idx entry is removed
+** too. This is done to ensure that if all instances of a token are
+** removed from an fts5 database in secure-delete mode, no trace of
+** the token itself remains in the database.
+*/
+static void fts5SecureDeleteIdxEntry(
+  Fts5Index *p,                   /* FTS5 backend object */
+  int iSegid,                     /* Id of segment to delete entry for */
+  int iPgno                       /* Page number within segment */
+){
+  if( iPgno!=1 ){
+    assert( p->pConfig->iVersion==FTS5_CURRENT_VERSION_SECUREDELETE );
+    if( p->pDeleteFromIdx==0 ){
+      fts5IndexPrepareStmt(p, &p->pDeleteFromIdx, sqlite3_mprintf(
+          "DELETE FROM '%q'.'%q_idx' WHERE (segid, (pgno/2)) = (?1, ?2)",
+          p->pConfig->zDb, p->pConfig->zName
+      ));
+    }
+    if( p->rc==SQLITE_OK ){
+      sqlite3_bind_int(p->pDeleteFromIdx, 1, iSegid);
+      sqlite3_bind_int(p->pDeleteFromIdx, 2, iPgno);
+      sqlite3_step(p->pDeleteFromIdx);
+      p->rc = sqlite3_reset(p->pDeleteFromIdx);
+    }
+  }
+}
+
+/*
+** This is called when a secure-delete operation removes a position-list
+** that overflows onto segment page iPgno of segment pSeg. This function
+** rewrites node iPgno, and possibly one or more of its right-hand peers,
+** to remove this portion of the position list.
+**
+** Output variable (*pbLastInDoclist) is set to true if the position-list
+** removed is followed by a new term or the end-of-segment, or false if
+** it is followed by another rowid/position list.
+*/
+static void fts5SecureDeleteOverflow(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,
+  int iPgno,
+  int *pbLastInDoclist
+){
+  const int bDetailNone = (p->pConfig->eDetail==FTS5_DETAIL_NONE);
+  int pgno;
+  Fts5Data *pLeaf = 0;
+  assert( iPgno!=1 );
+
+  *pbLastInDoclist = 1;
+  for(pgno=iPgno; p->rc==SQLITE_OK && pgno<=pSeg->pgnoLast; pgno++){
+    i64 iRowid = FTS5_SEGMENT_ROWID(pSeg->iSegid, pgno);
+    int iNext = 0;
+    u8 *aPg = 0;
+
+    pLeaf = fts5DataRead(p, iRowid);
+    if( pLeaf==0 ) break;
+    aPg = pLeaf->p;
+
+    iNext = fts5GetU16(&aPg[0]);
+    if( iNext!=0 ){
+      *pbLastInDoclist = 0;
+    }
+    if( iNext==0 && pLeaf->szLeaf!=pLeaf->nn ){
+      fts5GetVarint32(&aPg[pLeaf->szLeaf], iNext);
+    }
+
+    if( iNext==0 ){
+      /* The page contains no terms or rowids. Replace it with an empty
+      ** page and move on to the right-hand peer.  */
+      const u8 aEmpty[] = {0x00, 0x00, 0x00, 0x04};
+      assert_nc( bDetailNone==0 || pLeaf->nn==4 );
+      if( bDetailNone==0 ) fts5DataWrite(p, iRowid, aEmpty, sizeof(aEmpty));
+      fts5DataRelease(pLeaf);
+      pLeaf = 0;
+    }else if( bDetailNone ){
+      break;
+    }else if( iNext>=pLeaf->szLeaf || pLeaf->nn<pLeaf->szLeaf || iNext<4 ){
+      p->rc = FTS5_CORRUPT;
+      break;
+    }else{
+      int nShift = iNext - 4;
+      int nPg;
+
+      int nIdx = 0;
+      u8 *aIdx = 0;
+
+      /* Unless the current page footer is 0 bytes in size (in which case
+      ** the new page footer will be as well), allocate and populate a
+      ** buffer containing the new page footer. Set stack variables aIdx
+      ** and nIdx accordingly.  */
+      if( pLeaf->nn>pLeaf->szLeaf ){
+        int iFirst = 0;
+        int i1 = pLeaf->szLeaf;
+        int i2 = 0;
+
+        i1 += fts5GetVarint32(&aPg[i1], iFirst);
+        if( iFirst<iNext ){
+          p->rc = FTS5_CORRUPT;
+          break;
+        }
+        aIdx = sqlite3Fts5MallocZero(&p->rc, (pLeaf->nn-pLeaf->szLeaf)+2);
+        if( aIdx==0 ) break;
+        i2 = sqlite3Fts5PutVarint(aIdx, iFirst-nShift);
+        if( i1<pLeaf->nn ){
+          memcpy(&aIdx[i2], &aPg[i1], pLeaf->nn-i1);
+          i2 += (pLeaf->nn-i1);
+        }
+        nIdx = i2;
+      }
+
+      /* Modify the contents of buffer aPg[]. Set nPg to the new size
+      ** in bytes. The new page is always smaller than the old.  */
+      nPg = pLeaf->szLeaf - nShift;
+      memmove(&aPg[4], &aPg[4+nShift], nPg-4);
+      fts5PutU16(&aPg[2], nPg);
+      if( fts5GetU16(&aPg[0]) ) fts5PutU16(&aPg[0], 4);
+      if( nIdx>0 ){
+        memcpy(&aPg[nPg], aIdx, nIdx);
+        nPg += nIdx;
+      }
+      sqlite3_free(aIdx);
+
+      /* Write the new page to disk and exit the loop */
+      assert( nPg>4 || fts5GetU16(aPg)==0 );
+      fts5DataWrite(p, iRowid, aPg, nPg);
+      break;
+    }
+  }
+  fts5DataRelease(pLeaf);
+}
+
+/*
+** Completely remove the entry that pSeg currently points to from
+** the database.
+*/
+static void fts5DoSecureDelete(
+  Fts5Index *p,
+  Fts5SegIter *pSeg
+){
+  const int bDetailNone = (p->pConfig->eDetail==FTS5_DETAIL_NONE);
+  int iSegid = pSeg->pSeg->iSegid;
+  u8 *aPg = pSeg->pLeaf->p;
+  int nPg = pSeg->pLeaf->nn;
+  int iPgIdx = pSeg->pLeaf->szLeaf;
+
+  u64 iDelta = 0;
+  int iNextOff = 0;
+  int iOff = 0;
+  int nIdx = 0;
+  u8 *aIdx = 0;
+  int bLastInDoclist = 0;
+  int iIdx = 0;
+  int iStart = 0;
+  int iDelKeyOff = 0;       /* Offset of deleted key, if any */
+
+  nIdx = nPg-iPgIdx;
+  aIdx = sqlite3Fts5MallocZero(&p->rc, nIdx+16);
+  if( p->rc ) return;
+  memcpy(aIdx, &aPg[iPgIdx], nIdx);
+
+  /* At this point segment iterator pSeg points to the entry
+  ** this function should remove from the b-tree segment.
+  **
+  ** In detail=full or detail=column mode, pSeg->iLeafOffset is the
+  ** offset of the first byte in the position-list for the entry to
+  ** remove. Immediately before this comes two varints that will also
+  ** need to be removed:
+  **
+  **     + the rowid or delta rowid value for the entry, and
+  **     + the size of the position list in bytes.
+  **
+  ** Or, in detail=none mode, there is a single varint prior to
+  ** pSeg->iLeafOffset - the rowid or delta rowid value.
+  **
+  ** This block sets the following variables:
+  **
+  **   iStart:
+  **     The offset of the first byte of the rowid or delta-rowid
+  **     value for the doclist entry being removed.
+  **
+  **   iDelta:
+  **     The value of the rowid or delta-rowid value for the doclist
+  **     entry being removed.
+  **
+  **   iNextOff:
+  **     The offset of the next entry following the position list
+  **     for the one being removed. If the position list for this
+  **     entry overflows onto the next leaf page, this value will be
+  **     greater than pLeaf->szLeaf.
+  */
+  {
+    int iSOP;                     /* Start-Of-Position-list */
+    if( pSeg->iLeafPgno==pSeg->iTermLeafPgno ){
+      iStart = pSeg->iTermLeafOffset;
+    }else{
+      iStart = fts5GetU16(&aPg[0]);
+    }
+
+    iSOP = iStart + fts5GetVarint(&aPg[iStart], &iDelta);
+    assert_nc( iSOP<=pSeg->iLeafOffset );
+
+    if( bDetailNone ){
+      while( iSOP<pSeg->iLeafOffset ){
+        if( aPg[iSOP]==0x00 ) iSOP++;
+        if( aPg[iSOP]==0x00 ) iSOP++;
+        iStart = iSOP;
+        iSOP = iStart + fts5GetVarint(&aPg[iStart], &iDelta);
+      }
+
+      iNextOff = iSOP;
+      if( iNextOff<pSeg->iEndofDoclist && aPg[iNextOff]==0x00 ) iNextOff++;
+      if( iNextOff<pSeg->iEndofDoclist && aPg[iNextOff]==0x00 ) iNextOff++;
+
+    }else{
+      int nPos = 0;
+      iSOP += fts5GetVarint32(&aPg[iSOP], nPos);
+      while( iSOP<pSeg->iLeafOffset ){
+        iStart = iSOP + (nPos/2);
+        iSOP = iStart + fts5GetVarint(&aPg[iStart], &iDelta);
+        iSOP += fts5GetVarint32(&aPg[iSOP], nPos);
+      }
+      assert_nc( iSOP==pSeg->iLeafOffset );
+      iNextOff = pSeg->iLeafOffset + pSeg->nPos;
+    }
+  }
+
+  iOff = iStart;
+
+  /* If the position-list for the entry being removed flows over past
+  ** the end of this page, delete the portion of the position-list on the
+  ** next page and beyond.
+  **
+  ** Set variable bLastInDoclist to true if this entry happens
+  ** to be the last rowid in the doclist for its term.  */
+  if( iNextOff>=iPgIdx ){
+    int pgno = pSeg->iLeafPgno+1;
+    fts5SecureDeleteOverflow(p, pSeg->pSeg, pgno, &bLastInDoclist);
+    iNextOff = iPgIdx;
+  }
+
+  if( pSeg->bDel==0 ){
+    if( iNextOff!=iPgIdx ){
+      /* Loop through the page-footer. If iNextOff (offset of the
+      ** entry following the one we are removing) is equal to the
+      ** offset of a key on this page, then the entry is the last
+      ** in its doclist. */
+      int iKeyOff = 0;
+      for(iIdx=0; iIdx<nIdx; /* no-op */){
+        u32 iVal = 0;
+        iIdx += fts5GetVarint32(&aIdx[iIdx], iVal);
+        iKeyOff += iVal;
+        if( iKeyOff==iNextOff ){
+          bLastInDoclist = 1;
+        }
+      }
+    }
+
+    /* If this is (a) the first rowid on a page and (b) is not followed by
+    ** another position list on the same page, set the "first-rowid" field
+    ** of the header to 0.  */
+    if( fts5GetU16(&aPg[0])==iStart && (bLastInDoclist || iNextOff==iPgIdx) ){
+      fts5PutU16(&aPg[0], 0);
+    }
+  }
+
+  if( pSeg->bDel ){
+    iOff += sqlite3Fts5PutVarint(&aPg[iOff], iDelta);
+    aPg[iOff++] = 0x01;
+  }else if( bLastInDoclist==0 ){
+    if( iNextOff!=iPgIdx ){
+      u64 iNextDelta = 0;
+      iNextOff += fts5GetVarint(&aPg[iNextOff], &iNextDelta);
+      iOff += sqlite3Fts5PutVarint(&aPg[iOff], iDelta + iNextDelta);
+    }
+  }else if(
+      pSeg->iLeafPgno==pSeg->iTermLeafPgno
+   && iStart==pSeg->iTermLeafOffset
+  ){
+    /* The entry being removed was the only position list in its
+    ** doclist. Therefore the term needs to be removed as well. */
+    int iKey = 0;
+    int iKeyOff = 0;
+
+    /* Set iKeyOff to the offset of the term that will be removed - the
+    ** last offset in the footer that is not greater than iStart. */
+    for(iIdx=0; iIdx<nIdx; iKey++){
+      u32 iVal = 0;
+      iIdx += fts5GetVarint32(&aIdx[iIdx], iVal);
+      if( (iKeyOff+iVal)>(u32)iStart ) break;
+      iKeyOff += iVal;
+    }
+    assert_nc( iKey>=1 );
+
+    /* Set iDelKeyOff to the value of the footer entry to remove from
+    ** the page. */
+    iDelKeyOff = iOff = iKeyOff;
+
+    if( iNextOff!=iPgIdx ){
+      /* This is the only position-list associated with the term, and there
+      ** is another term following it on this page. So the subsequent term
+      ** needs to be moved to replace the term associated with the entry
+      ** being removed. */
+      int nPrefix = 0;
+      int nSuffix = 0;
+      int nPrefix2 = 0;
+      int nSuffix2 = 0;
+
+      iDelKeyOff = iNextOff;
+      iNextOff += fts5GetVarint32(&aPg[iNextOff], nPrefix2);
+      iNextOff += fts5GetVarint32(&aPg[iNextOff], nSuffix2);
+
+      if( iKey!=1 ){
+        iKeyOff += fts5GetVarint32(&aPg[iKeyOff], nPrefix);
+      }
+      iKeyOff += fts5GetVarint32(&aPg[iKeyOff], nSuffix);
+
+      nPrefix = MIN(nPrefix, nPrefix2);
+      nSuffix = (nPrefix2 + nSuffix2) - nPrefix;
+
+      if( (iKeyOff+nSuffix)>iPgIdx || (iNextOff+nSuffix2)>iPgIdx ){
+        p->rc = FTS5_CORRUPT;
+      }else{
+        if( iKey!=1 ){
+          iOff += sqlite3Fts5PutVarint(&aPg[iOff], nPrefix);
+        }
+        iOff += sqlite3Fts5PutVarint(&aPg[iOff], nSuffix);
+        if( nPrefix2>pSeg->term.n ){
+          p->rc = FTS5_CORRUPT;
+        }else if( nPrefix2>nPrefix ){
+          memcpy(&aPg[iOff], &pSeg->term.p[nPrefix], nPrefix2-nPrefix);
+          iOff += (nPrefix2-nPrefix);
+        }
+        memmove(&aPg[iOff], &aPg[iNextOff], nSuffix2);
+        iOff += nSuffix2;
+        iNextOff += nSuffix2;
+      }
+    }
+  }else if( iStart==4 ){
+    int iPgno;
+
+    assert_nc( pSeg->iLeafPgno>pSeg->iTermLeafPgno );
+    /* The entry being removed may be the only position list in
+    ** its doclist. */
+    for(iPgno=pSeg->iLeafPgno-1; iPgno>pSeg->iTermLeafPgno; iPgno-- ){
+      Fts5Data *pPg = fts5DataRead(p, FTS5_SEGMENT_ROWID(iSegid, iPgno));
+      int bEmpty = (pPg && pPg->nn==4);
+      fts5DataRelease(pPg);
+      if( bEmpty==0 ) break;
+    }
+
+    if( iPgno==pSeg->iTermLeafPgno ){
+      i64 iId = FTS5_SEGMENT_ROWID(iSegid, pSeg->iTermLeafPgno);
+      Fts5Data *pTerm = fts5DataRead(p, iId);
+      if( pTerm && pTerm->szLeaf==pSeg->iTermLeafOffset ){
+        u8 *aTermIdx = &pTerm->p[pTerm->szLeaf];
+        int nTermIdx = pTerm->nn - pTerm->szLeaf;
+        int iTermIdx = 0;
+        int iTermOff = 0;
+
+        while( 1 ){
+          u32 iVal = 0;
+          int nByte = fts5GetVarint32(&aTermIdx[iTermIdx], iVal);
+          iTermOff += iVal;
+          if( (iTermIdx+nByte)>=nTermIdx ) break;
+          iTermIdx += nByte;
+        }
+        nTermIdx = iTermIdx;
+
+        memmove(&pTerm->p[iTermOff], &pTerm->p[pTerm->szLeaf], nTermIdx);
+        fts5PutU16(&pTerm->p[2], iTermOff);
+
+        fts5DataWrite(p, iId, pTerm->p, iTermOff+nTermIdx);
+        if( nTermIdx==0 ){
+          fts5SecureDeleteIdxEntry(p, iSegid, pSeg->iTermLeafPgno);
+        }
+      }
+      fts5DataRelease(pTerm);
+    }
+  }
+
+  /* Assuming no error has occurred, this block does final edits to the
+  ** leaf page before writing it back to disk. Input variables are:
+  **
+  **   nPg: Total initial size of leaf page.
+  **   iPgIdx: Initial offset of page footer.
+  **
+  **   iOff: Offset to move data to
+  **   iNextOff: Offset to move data from
+  */
+  if( p->rc==SQLITE_OK ){
+    const int nMove = nPg - iNextOff;     /* Number of bytes to move */
+    int nShift = iNextOff - iOff;         /* Distance to move them */
+
+    int iPrevKeyOut = 0;
+    int iKeyIn = 0;
+
+    memmove(&aPg[iOff], &aPg[iNextOff], nMove);
+    iPgIdx -= nShift;
+    nPg = iPgIdx;
+    fts5PutU16(&aPg[2], iPgIdx);
+
+    for(iIdx=0; iIdx<nIdx; /* no-op */){
+      u32 iVal = 0;
+      iIdx += fts5GetVarint32(&aIdx[iIdx], iVal);
+      iKeyIn += iVal;
+      if( iKeyIn!=iDelKeyOff ){
+        int iKeyOut = (iKeyIn - (iKeyIn>iOff ? nShift : 0));
+        nPg += sqlite3Fts5PutVarint(&aPg[nPg], iKeyOut - iPrevKeyOut);
+        iPrevKeyOut = iKeyOut;
+      }
+    }
+
+    if( iPgIdx==nPg && nIdx>0 && pSeg->iLeafPgno!=1 ){
+      fts5SecureDeleteIdxEntry(p, iSegid, pSeg->iLeafPgno);
+    }
+
+    assert_nc( nPg>4 || fts5GetU16(aPg)==0 );
+    fts5DataWrite(p, FTS5_SEGMENT_ROWID(iSegid,pSeg->iLeafPgno), aPg, nPg);
+  }
+  sqlite3_free(aIdx);
+}
+
+/*
+** This is called as part of flushing a delete to disk in 'secure-delete'
+** mode. It edits the segments within the database described by argument
+** pStruct to remove the entries for term zTerm, rowid iRowid.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** has occurred. Any error code is also stored in the Fts5Index handle.
+*/
+static int fts5FlushSecureDelete(
+  Fts5Index *p,
+  Fts5Structure *pStruct,
+  const char *zTerm,
+  int nTerm,
+  i64 iRowid
+){
+  const int f = FTS5INDEX_QUERY_SKIPHASH;
+  Fts5Iter *pIter = 0;            /* Used to find term instance */
+
+  /* If the version number has not been set to SECUREDELETE, do so now. */
+  if( p->pConfig->iVersion!=FTS5_CURRENT_VERSION_SECUREDELETE ){
+    Fts5Config *pConfig = p->pConfig;
+    sqlite3_stmt *pStmt = 0;
+    fts5IndexPrepareStmt(p, &pStmt, sqlite3_mprintf(
+          "REPLACE INTO %Q.'%q_config' VALUES ('version', %d)",
+          pConfig->zDb, pConfig->zName, FTS5_CURRENT_VERSION_SECUREDELETE
+    ));
+    if( p->rc==SQLITE_OK ){
+      int rc;
+      sqlite3_step(pStmt);
+      rc = sqlite3_finalize(pStmt);
+      if( p->rc==SQLITE_OK ) p->rc = rc;
+      pConfig->iCookie++;
+      pConfig->iVersion = FTS5_CURRENT_VERSION_SECUREDELETE;
+    }
+  }
+
+  fts5MultiIterNew(p, pStruct, f, 0, (const u8*)zTerm, nTerm, -1, 0, &pIter);
+  if( fts5MultiIterEof(p, pIter)==0 ){
+    i64 iThis = fts5MultiIterRowid(pIter);
+    if( iThis<iRowid ){
+      fts5MultiIterNextFrom(p, pIter, iRowid);
+    }
+
+    if( p->rc==SQLITE_OK
+     && fts5MultiIterEof(p, pIter)==0
+     && iRowid==fts5MultiIterRowid(pIter)
+    ){
+      Fts5SegIter *pSeg = &pIter->aSeg[pIter->aFirst[1].iFirst];
+      fts5DoSecureDelete(p, pSeg);
+    }
+  }
+
+  fts5MultiIterFree(pIter);
+  return p->rc;
+}
+
+
+/*
+** Flush the contents of in-memory hash table iHash to a new level-0
+** segment on disk. Also update the corresponding structure record.
+**
+** If an error occurs, set the Fts5Index.rc error code. If an error has
+** already occurred, this function is a no-op.
+*/
+static void fts5FlushOneHash(Fts5Index *p){
+  Fts5Hash *pHash = p->pHash;
+  Fts5Structure *pStruct;
+  int iSegid;
+  int pgnoLast = 0;                 /* Last leaf page number in segment */
+
+  /* Obtain a reference to the index structure and allocate a new segment-id
+  ** for the new level-0 segment.  */
+  pStruct = fts5StructureRead(p);
+  fts5StructureInvalidate(p);
+
+  if( sqlite3Fts5HashIsEmpty(pHash)==0 ){
+    iSegid = fts5AllocateSegid(p, pStruct);
+    if( iSegid ){
+      const int pgsz = p->pConfig->pgsz;
+      int eDetail = p->pConfig->eDetail;
+      int bSecureDelete = p->pConfig->bSecureDelete;
+      Fts5StructureSegment *pSeg; /* New segment within pStruct */
+      Fts5Buffer *pBuf;           /* Buffer in which to assemble leaf page */
+      Fts5Buffer *pPgidx;         /* Buffer in which to assemble pgidx */
+
+      Fts5SegWriter writer;
+      fts5WriteInit(p, &writer, iSegid);
+
+      pBuf = &writer.writer.buf;
+      pPgidx = &writer.writer.pgidx;
+
+      /* fts5WriteInit() should have initialized the buffers to (most likely)
+      ** the maximum space required. */
+      assert( p->rc || pBuf->nSpace>=(pgsz + FTS5_DATA_PADDING) );
+      assert( p->rc || pPgidx->nSpace>=(pgsz + FTS5_DATA_PADDING) );
+
+      /* Begin scanning through hash table entries. This loop runs once for each
+      ** term/doclist currently stored within the hash table. */
+      if( p->rc==SQLITE_OK ){
+        p->rc = sqlite3Fts5HashScanInit(pHash, 0, 0);
+      }
+      while( p->rc==SQLITE_OK && 0==sqlite3Fts5HashScanEof(pHash) ){
+        const char *zTerm;        /* Buffer containing term */
+        int nTerm;                /* Size of zTerm in bytes */
+        const u8 *pDoclist;       /* Pointer to doclist for this term */
+        int nDoclist;             /* Size of doclist in bytes */
+
+        /* Get the term and doclist for this entry. */
+        sqlite3Fts5HashScanEntry(pHash, &zTerm, &nTerm, &pDoclist, &nDoclist);
+        if( bSecureDelete==0 ){
+          fts5WriteAppendTerm(p, &writer, nTerm, (const u8*)zTerm);
+          if( p->rc!=SQLITE_OK ) break;
+          assert( writer.bFirstRowidInPage==0 );
+        }
+
+        if( !bSecureDelete && pgsz>=(pBuf->n + pPgidx->n + nDoclist + 1) ){
+          /* The entire doclist will fit on the current leaf. */
+          fts5BufferSafeAppendBlob(pBuf, pDoclist, nDoclist);
+        }else{
+          int bTermWritten = !bSecureDelete;
+          i64 iRowid = 0;
+          i64 iPrev = 0;
+          int iOff = 0;
+
+          /* The entire doclist will not fit on this leaf. The following
+          ** loop iterates through the poslists that make up the current
+          ** doclist.  */
+          while( p->rc==SQLITE_OK && iOff<nDoclist ){
+            u64 iDelta = 0;
+            iOff += fts5GetVarint(&pDoclist[iOff], &iDelta);
+            iRowid += iDelta;
+
+            /* If in secure delete mode, and if this entry in the poslist is
+            ** in fact a delete, then edit the existing segments directly
+            ** using fts5FlushSecureDelete().  */
+            if( bSecureDelete ){
+              if( eDetail==FTS5_DETAIL_NONE ){
+                if( iOff<nDoclist && pDoclist[iOff]==0x00
+                 && !fts5FlushSecureDelete(p, pStruct, zTerm, nTerm, iRowid)
+                ){
+                  iOff++;
+                  if( iOff<nDoclist && pDoclist[iOff]==0x00 ){
+                    iOff++;
+                    nDoclist = 0;
+                  }else{
+                    continue;
+                  }
+                }
+              }else if( (pDoclist[iOff] & 0x01)
+                && !fts5FlushSecureDelete(p, pStruct, zTerm, nTerm, iRowid)
+              ){
+                if( p->rc!=SQLITE_OK || pDoclist[iOff]==0x01 ){
+                  iOff++;
+                  continue;
+                }
+              }
+            }
+
+            if( p->rc==SQLITE_OK && bTermWritten==0 ){
+              fts5WriteAppendTerm(p, &writer, nTerm, (const u8*)zTerm);
+              bTermWritten = 1;
+              assert( p->rc!=SQLITE_OK || writer.bFirstRowidInPage==0 );
+            }
+
+            if( writer.bFirstRowidInPage ){
+              fts5PutU16(&pBuf->p[0], (u16)pBuf->n);   /* first rowid on page */
+              pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], iRowid);
+              writer.bFirstRowidInPage = 0;
+              fts5WriteDlidxAppend(p, &writer, iRowid);
+            }else{
+              u64 iRowidDelta = (u64)iRowid - (u64)iPrev;
+              pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], iRowidDelta);
+            }
+            if( p->rc!=SQLITE_OK ) break;
+            assert( pBuf->n<=pBuf->nSpace );
+            iPrev = iRowid;
+
+            if( eDetail==FTS5_DETAIL_NONE ){
+              if( iOff<nDoclist && pDoclist[iOff]==0 ){
+                pBuf->p[pBuf->n++] = 0;
+                iOff++;
+                if( iOff<nDoclist && pDoclist[iOff]==0 ){
+                  pBuf->p[pBuf->n++] = 0;
+                  iOff++;
+                }
+              }
+              if( (pBuf->n + pPgidx->n)>=pgsz ){
+                fts5WriteFlushLeaf(p, &writer);
+              }
+            }else{
+              int bDel = 0;
+              int nPos = 0;
+              int nCopy = fts5GetPoslistSize(&pDoclist[iOff], &nPos, &bDel);
+              if( bDel && bSecureDelete ){
+                fts5BufferAppendVarint(&p->rc, pBuf, nPos*2);
+                iOff += nCopy;
+                nCopy = nPos;
+              }else{
+                nCopy += nPos;
+              }
+              if( (pBuf->n + pPgidx->n + nCopy) <= pgsz ){
+                /* The entire poslist will fit on the current leaf. So copy
+                ** it in one go. */
+                fts5BufferSafeAppendBlob(pBuf, &pDoclist[iOff], nCopy);
+              }else{
+                /* The entire poslist will not fit on this leaf. So it needs
+                ** to be broken into sections. The only qualification being
+                ** that each varint must be stored contiguously.  */
+                const u8 *pPoslist = &pDoclist[iOff];
+                int iPos = 0;
+                while( p->rc==SQLITE_OK ){
+                  int nSpace = pgsz - pBuf->n - pPgidx->n;
+                  int n = 0;
+                  if( (nCopy - iPos)<=nSpace ){
+                    n = nCopy - iPos;
+                  }else{
+                    n = fts5PoslistPrefix(&pPoslist[iPos], nSpace);
+                  }
+                  assert( n>0 );
+                  fts5BufferSafeAppendBlob(pBuf, &pPoslist[iPos], n);
+                  iPos += n;
+                  if( (pBuf->n + pPgidx->n)>=pgsz ){
+                    fts5WriteFlushLeaf(p, &writer);
+                  }
+                  if( iPos>=nCopy ) break;
+                }
+              }
+              iOff += nCopy;
+            }
+          }
+        }
+
+        /* TODO2: Doclist terminator written here. */
+        /* pBuf->p[pBuf->n++] = '\0'; */
+        assert( pBuf->n<=pBuf->nSpace );
+        if( p->rc==SQLITE_OK ) sqlite3Fts5HashScanNext(pHash);
+      }
+      fts5WriteFinish(p, &writer, &pgnoLast);
+
+      assert( p->rc!=SQLITE_OK || bSecureDelete || pgnoLast>0 );
+      if( pgnoLast>0 ){
+        /* Update the Fts5Structure. It is written back to the database by the
+        ** fts5StructureRelease() call below.  */
+        if( pStruct->nLevel==0 ){
+          fts5StructureAddLevel(&p->rc, &pStruct);
+        }
+        fts5StructureExtendLevel(&p->rc, pStruct, 0, 1, 0);
+        if( p->rc==SQLITE_OK ){
+          pSeg = &pStruct->aLevel[0].aSeg[ pStruct->aLevel[0].nSeg++ ];
+          pSeg->iSegid = iSegid;
+          pSeg->pgnoFirst = 1;
+          pSeg->pgnoLast = pgnoLast;
+          if( pStruct->nOriginCntr>0 ){
+            pSeg->iOrigin1 = pStruct->nOriginCntr;
+            pSeg->iOrigin2 = pStruct->nOriginCntr;
+            pSeg->nEntry = p->nPendingRow;
+            pStruct->nOriginCntr++;
+          }
+          pStruct->nSegment++;
+        }
+        fts5StructurePromote(p, 0, pStruct);
+      }
+    }
+  }
+
+  fts5IndexAutomerge(p, &pStruct, pgnoLast + p->nContentlessDelete);
+  fts5IndexCrisismerge(p, &pStruct);
+  fts5StructureWrite(p, pStruct);
+  fts5StructureRelease(pStruct);
+}
+
+/*
+** Flush any data stored in the in-memory hash tables to the database.
+*/
+static void fts5IndexFlush(Fts5Index *p){
+  /* Unless it is empty, flush the hash table to disk */
+  if( p->flushRc ){
+    p->rc = p->flushRc;
+    return;
+  }
+  if( p->nPendingData || p->nContentlessDelete ){
+    assert( p->pHash );
+    fts5FlushOneHash(p);
+    if( p->rc==SQLITE_OK ){
+      sqlite3Fts5HashClear(p->pHash);
+      p->nPendingData = 0;
+      p->nPendingRow = 0;
+      p->nContentlessDelete = 0;
+    }else if( p->nPendingData || p->nContentlessDelete ){
+      p->flushRc = p->rc;
+    }
+  }
+}
+
+static Fts5Structure *fts5IndexOptimizeStruct(
+  Fts5Index *p,
+  Fts5Structure *pStruct
+){
+  Fts5Structure *pNew = 0;
+  sqlite3_int64 nByte = sizeof(Fts5Structure);
+  int nSeg = pStruct->nSegment;
+  int i;
+
+  /* Figure out if this structure requires optimization. A structure does
+  ** not require optimization if either:
+  **
+  **  1. it consists of fewer than two segments, or
+  **  2. all segments are on the same level, or
+  **  3. all segments except one are currently inputs to a merge operation.
+  **
+  ** In the first case, if there are no tombstone hash pages, return NULL. In
+  ** the second, increment the ref-count on *pStruct and return a copy of the
+  ** pointer to it.
+  */
+  if( nSeg==0 ) return 0;
+  for(i=0; i<pStruct->nLevel; i++){
+    int nThis = pStruct->aLevel[i].nSeg;
+    int nMerge = pStruct->aLevel[i].nMerge;
+    if( nThis>0 && (nThis==nSeg || (nThis==nSeg-1 && nMerge==nThis)) ){
+      if( nSeg==1 && nThis==1 && pStruct->aLevel[i].aSeg[0].nPgTombstone==0 ){
+        return 0;
+      }
+      fts5StructureRef(pStruct);
+      return pStruct;
+    }
+    assert( pStruct->aLevel[i].nMerge<=nThis );
+  }
+
+  nByte += (pStruct->nLevel+1) * sizeof(Fts5StructureLevel);
+  pNew = (Fts5Structure*)sqlite3Fts5MallocZero(&p->rc, nByte);
+
+  if( pNew ){
+    Fts5StructureLevel *pLvl;
+    nByte = nSeg * sizeof(Fts5StructureSegment);
+    pNew->nLevel = MIN(pStruct->nLevel+1, FTS5_MAX_LEVEL);
+    pNew->nRef = 1;
+    pNew->nWriteCounter = pStruct->nWriteCounter;
+    pNew->nOriginCntr = pStruct->nOriginCntr;
+    pLvl = &pNew->aLevel[pNew->nLevel-1];
+    pLvl->aSeg = (Fts5StructureSegment*)sqlite3Fts5MallocZero(&p->rc, nByte);
+    if( pLvl->aSeg ){
+      int iLvl, iSeg;
+      int iSegOut = 0;
+      /* Iterate through all segments, from oldest to newest. Add them to
+      ** the new Fts5Level object so that pLvl->aSeg[0] is the oldest
+      ** segment in the data structure.  */
+      for(iLvl=pStruct->nLevel-1; iLvl>=0; iLvl--){
+        for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
+          pLvl->aSeg[iSegOut] = pStruct->aLevel[iLvl].aSeg[iSeg];
+          iSegOut++;
+        }
+      }
+      pNew->nSegment = pLvl->nSeg = nSeg;
+    }else{
+      sqlite3_free(pNew);
+      pNew = 0;
+    }
+  }
+
+  return pNew;
+}
+
+static int sqlite3Fts5IndexOptimize(Fts5Index *p){
+  Fts5Structure *pStruct;
+  Fts5Structure *pNew = 0;
+
+  assert( p->rc==SQLITE_OK );
+  fts5IndexFlush(p);
+  assert( p->rc!=SQLITE_OK || p->nContentlessDelete==0 );
+  pStruct = fts5StructureRead(p);
+  assert( p->rc!=SQLITE_OK || pStruct!=0 );
+  fts5StructureInvalidate(p);
+
+  if( pStruct ){
+    pNew = fts5IndexOptimizeStruct(p, pStruct);
+  }
+  fts5StructureRelease(pStruct);
+
+  assert( pNew==0 || pNew->nSegment>0 );
+  if( pNew ){
+    int iLvl;
+    for(iLvl=0; pNew->aLevel[iLvl].nSeg==0; iLvl++){}
+    while( p->rc==SQLITE_OK && pNew->aLevel[iLvl].nSeg>0 ){
+      int nRem = FTS5_OPT_WORK_UNIT;
+      fts5IndexMergeLevel(p, &pNew, iLvl, &nRem);
+    }
+
+    fts5StructureWrite(p, pNew);
+    fts5StructureRelease(pNew);
+  }
+
+  return fts5IndexReturn(p);
+}
+
+/*
+** This is called to implement the special "VALUES('merge', $nMerge)"
+** INSERT command.
+*/
+static int sqlite3Fts5IndexMerge(Fts5Index *p, int nMerge){
+  Fts5Structure *pStruct = 0;
+
+  fts5IndexFlush(p);
+  pStruct = fts5StructureRead(p);
+  if( pStruct ){
+    int nMin = p->pConfig->nUsermerge;
+    fts5StructureInvalidate(p);
+    if( nMerge<0 ){
+      Fts5Structure *pNew = fts5IndexOptimizeStruct(p, pStruct);
+      fts5StructureRelease(pStruct);
+      pStruct = pNew;
+      nMin = 1;
+      nMerge = nMerge*-1;
+    }
+    if( pStruct && pStruct->nLevel ){
+      if( fts5IndexMerge(p, &pStruct, nMerge, nMin) ){
+        fts5StructureWrite(p, pStruct);
+      }
+    }
+    fts5StructureRelease(pStruct);
+  }
+  return fts5IndexReturn(p);
+}
+
+static void fts5AppendRowid(
+  Fts5Index *p,
+  u64 iDelta,
+  Fts5Iter *pUnused,
+  Fts5Buffer *pBuf
+){
+  UNUSED_PARAM(pUnused);
+  fts5BufferAppendVarint(&p->rc, pBuf, iDelta);
+}
+
+static void fts5AppendPoslist(
+  Fts5Index *p,
+  u64 iDelta,
+  Fts5Iter *pMulti,
+  Fts5Buffer *pBuf
+){
+  int nData = pMulti->base.nData;
+  int nByte = nData + 9 + 9 + FTS5_DATA_ZERO_PADDING;
+  assert( nData>0 );
+  if( p->rc==SQLITE_OK && 0==fts5BufferGrow(&p->rc, pBuf, nByte) ){
+    fts5BufferSafeAppendVarint(pBuf, iDelta);
+    fts5BufferSafeAppendVarint(pBuf, nData*2);
+    fts5BufferSafeAppendBlob(pBuf, pMulti->base.pData, nData);
+    memset(&pBuf->p[pBuf->n], 0, FTS5_DATA_ZERO_PADDING);
+  }
+}
+
+
+static void fts5DoclistIterNext(Fts5DoclistIter *pIter){
+  u8 *p = pIter->aPoslist + pIter->nSize + pIter->nPoslist;
+
+  assert( pIter->aPoslist || (p==0 && pIter->aPoslist==0) );
+  if( p>=pIter->aEof ){
+    pIter->aPoslist = 0;
+  }else{
+    i64 iDelta;
+
+    p += fts5GetVarint(p, (u64*)&iDelta);
+    pIter->iRowid += iDelta;
+
+    /* Read position list size */
+    if( p[0] & 0x80 ){
+      int nPos;
+      pIter->nSize = fts5GetVarint32(p, nPos);
+      pIter->nPoslist = (nPos>>1);
+    }else{
+      pIter->nPoslist = ((int)(p[0])) >> 1;
+      pIter->nSize = 1;
+    }
+
+    pIter->aPoslist = p;
+    if( &pIter->aPoslist[pIter->nPoslist]>pIter->aEof ){
+      pIter->aPoslist = 0;
+    }
+  }
+}
+
+static void fts5DoclistIterInit(
+  Fts5Buffer *pBuf,
+  Fts5DoclistIter *pIter
+){
+  memset(pIter, 0, sizeof(*pIter));
+  if( pBuf->n>0 ){
+    pIter->aPoslist = pBuf->p;
+    pIter->aEof = &pBuf->p[pBuf->n];
+    fts5DoclistIterNext(pIter);
+  }
+}
+
+#if 0
+/*
+** Append a doclist to buffer pBuf.
+**
+** This function assumes that space within the buffer has already been
+** allocated.
+*/
+static void fts5MergeAppendDocid(
+  Fts5Buffer *pBuf,               /* Buffer to write to */
+  i64 *piLastRowid,               /* IN/OUT: Previous rowid written (if any) */
+  i64 iRowid                      /* Rowid to append */
+){
+  assert( pBuf->n!=0 || (*piLastRowid)==0 );
+  fts5BufferSafeAppendVarint(pBuf, iRowid - *piLastRowid);
+  *piLastRowid = iRowid;
+}
+#endif
+
+#define fts5MergeAppendDocid(pBuf, iLastRowid, iRowid) {                 \
+  assert( (pBuf)->n!=0 || (iLastRowid)==0 );                             \
+  fts5BufferSafeAppendVarint((pBuf), (u64)(iRowid) - (u64)(iLastRowid)); \
+  (iLastRowid) = (iRowid);                                               \
+}
+
+/*
+** Swap the contents of buffer *p1 with that of *p2.
+*/
+static void fts5BufferSwap(Fts5Buffer *p1, Fts5Buffer *p2){
+  Fts5Buffer tmp = *p1;
+  *p1 = *p2;
+  *p2 = tmp;
+}
+
+static void fts5NextRowid(Fts5Buffer *pBuf, int *piOff, i64 *piRowid){
+  int i = *piOff;
+  if( i>=pBuf->n ){
+    *piOff = -1;
+  }else{
+    u64 iVal;
+    *piOff = i + sqlite3Fts5GetVarint(&pBuf->p[i], &iVal);
+    *piRowid += iVal;
+  }
+}
+
+/*
+** This is the equivalent of fts5MergePrefixLists() for detail=none mode.
+** In this case the buffers consist of a delta-encoded list of rowids only.
+*/
+static void fts5MergeRowidLists(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Buffer *p1,                 /* First list to merge */
+  int nBuf,                       /* Number of entries in apBuf[] */
+  Fts5Buffer *aBuf                /* Array of other lists to merge into p1 */
+){
+  int i1 = 0;
+  int i2 = 0;
+  i64 iRowid1 = 0;
+  i64 iRowid2 = 0;
+  i64 iOut = 0;
+  Fts5Buffer *p2 = &aBuf[0];
+  Fts5Buffer out;
+
+  (void)nBuf;
+  memset(&out, 0, sizeof(out));
+  assert( nBuf==1 );
+  sqlite3Fts5BufferSize(&p->rc, &out, p1->n + p2->n);
+  if( p->rc ) return;
+
+  fts5NextRowid(p1, &i1, &iRowid1);
+  fts5NextRowid(p2, &i2, &iRowid2);
+  while( i1>=0 || i2>=0 ){
+    if( i1>=0 && (i2<0 || iRowid1<iRowid2) ){
+      assert( iOut==0 || iRowid1>iOut );
+      fts5BufferSafeAppendVarint(&out, iRowid1 - iOut);
+      iOut = iRowid1;
+      fts5NextRowid(p1, &i1, &iRowid1);
+    }else{
+      assert( iOut==0 || iRowid2>iOut );
+      fts5BufferSafeAppendVarint(&out, iRowid2 - iOut);
+      iOut = iRowid2;
+      if( i1>=0 && iRowid1==iRowid2 ){
+        fts5NextRowid(p1, &i1, &iRowid1);
+      }
+      fts5NextRowid(p2, &i2, &iRowid2);
+    }
+  }
+
+  fts5BufferSwap(&out, p1);
+  fts5BufferFree(&out);
+}
+
+typedef struct PrefixMerger PrefixMerger;
+struct PrefixMerger {
+  Fts5DoclistIter iter;           /* Doclist iterator */
+  i64 iPos;                       /* For iterating through a position list */
+  int iOff;
+  u8 *aPos;
+  PrefixMerger *pNext;            /* Next in docid/poslist order */
+};
+
+static void fts5PrefixMergerInsertByRowid(
+  PrefixMerger **ppHead,
+  PrefixMerger *p
+){
+  if( p->iter.aPoslist ){
+    PrefixMerger **pp = ppHead;
+    while( *pp && p->iter.iRowid>(*pp)->iter.iRowid ){
+      pp = &(*pp)->pNext;
+    }
+    p->pNext = *pp;
+    *pp = p;
+  }
+}
+
+static void fts5PrefixMergerInsertByPosition(
+  PrefixMerger **ppHead,
+  PrefixMerger *p
+){
+  if( p->iPos>=0 ){
+    PrefixMerger **pp = ppHead;
+    while( *pp && p->iPos>(*pp)->iPos ){
+      pp = &(*pp)->pNext;
+    }
+    p->pNext = *pp;
+    *pp = p;
+  }
+}
+
+
+/*
+** Array aBuf[] contains nBuf doclists. These are all merged in with the
+** doclist in buffer p1.
+*/
+static void fts5MergePrefixLists(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Buffer *p1,                 /* First list to merge */
+  int nBuf,                       /* Number of buffers in array aBuf[] */
+  Fts5Buffer *aBuf                /* Other lists to merge in */
+){
+#define fts5PrefixMergerNextPosition(p) \
+  sqlite3Fts5PoslistNext64((p)->aPos,(p)->iter.nPoslist,&(p)->iOff,&(p)->iPos)
+#define FTS5_MERGE_NLIST 16
+  PrefixMerger aMerger[FTS5_MERGE_NLIST];
+  PrefixMerger *pHead = 0;
+  int i;
+  int nOut = 0;
+  Fts5Buffer out = {0, 0, 0};
+  Fts5Buffer tmp = {0, 0, 0};
+  i64 iLastRowid = 0;
+
+  /* Initialize a doclist-iterator for each input buffer. Arrange them in
+  ** a linked-list starting at pHead in ascending order of rowid. Avoid
+  ** linking any iterators already at EOF into the linked list at all. */
+  assert( nBuf+1<=(int)(sizeof(aMerger)/sizeof(aMerger[0])) );
+  memset(aMerger, 0, sizeof(PrefixMerger)*(nBuf+1));
+  pHead = &aMerger[nBuf];
+  fts5DoclistIterInit(p1, &pHead->iter);
+  for(i=0; i<nBuf; i++){
+    fts5DoclistIterInit(&aBuf[i], &aMerger[i].iter);
+    fts5PrefixMergerInsertByRowid(&pHead, &aMerger[i]);
+    nOut += aBuf[i].n;
+  }
+  if( nOut==0 ) return;
+  nOut += p1->n + 9 + 10*nBuf;
+
+  /* The maximum size of the output is equal to the sum of the
+  ** input sizes + 1 varint (9 bytes). The extra varint is because if the
+  ** first rowid in one input is a large negative number, and the first in
+  ** the other a non-negative number, the delta for the non-negative
+  ** number will be larger on disk than the literal integer value
+  ** was.
+  **
+  ** Or, if the input position-lists are corrupt, then the output might
+  ** include up to (nBuf+1) extra 10-byte positions created by interpreting -1
+  ** (the value PoslistNext64() uses for EOF) as a position and appending
+  ** it to the output. This can happen at most once for each input
+  ** position-list, hence (nBuf+1) 10 byte paddings.  */
+  if( sqlite3Fts5BufferSize(&p->rc, &out, nOut) ) return;
+
+  while( pHead ){
+    fts5MergeAppendDocid(&out, iLastRowid, pHead->iter.iRowid);
+
+    if( pHead->pNext && iLastRowid==pHead->pNext->iter.iRowid ){
+      /* Merge data from two or more poslists */
+      i64 iPrev = 0;
+      int nTmp = FTS5_DATA_ZERO_PADDING;
+      int nMerge = 0;
+      PrefixMerger *pSave = pHead;
+      PrefixMerger *pThis = 0;
+      int nTail = 0;
+
+      pHead = 0;
+      while( pSave && pSave->iter.iRowid==iLastRowid ){
+        PrefixMerger *pNext = pSave->pNext;
+        pSave->iOff = 0;
+        pSave->iPos = 0;
+        pSave->aPos = &pSave->iter.aPoslist[pSave->iter.nSize];
+        fts5PrefixMergerNextPosition(pSave);
+        nTmp += pSave->iter.nPoslist + 10;
+        nMerge++;
+        fts5PrefixMergerInsertByPosition(&pHead, pSave);
+        pSave = pNext;
+      }
+
+      if( pHead==0 || pHead->pNext==0 ){
+        p->rc = FTS5_CORRUPT;
+        break;
+      }
+
+      /* See the earlier comment in this function for an explanation of why
+      ** corrupt input position lists might cause the output to consume
+      ** at most nMerge*10 bytes of unexpected space. */
+      if( sqlite3Fts5BufferSize(&p->rc, &tmp, nTmp+nMerge*10) ){
+        break;
+      }
+      fts5BufferZero(&tmp);
+
+      pThis = pHead;
+      pHead = pThis->pNext;
+      sqlite3Fts5PoslistSafeAppend(&tmp, &iPrev, pThis->iPos);
+      fts5PrefixMergerNextPosition(pThis);
+      fts5PrefixMergerInsertByPosition(&pHead, pThis);
+
+      while( pHead->pNext ){
+        pThis = pHead;
+        if( pThis->iPos!=iPrev ){
+          sqlite3Fts5PoslistSafeAppend(&tmp, &iPrev, pThis->iPos);
+        }
+        fts5PrefixMergerNextPosition(pThis);
+        pHead = pThis->pNext;
+        fts5PrefixMergerInsertByPosition(&pHead, pThis);
+      }
+
+      if( pHead->iPos!=iPrev ){
+        sqlite3Fts5PoslistSafeAppend(&tmp, &iPrev, pHead->iPos);
+      }
+      nTail = pHead->iter.nPoslist - pHead->iOff;
+
+      /* WRITEPOSLISTSIZE */
+      assert_nc( tmp.n+nTail<=nTmp );
+      assert( tmp.n+nTail<=nTmp+nMerge*10 );
+      if( tmp.n+nTail>nTmp-FTS5_DATA_ZERO_PADDING ){
+        if( p->rc==SQLITE_OK ) p->rc = FTS5_CORRUPT;
+        break;
+      }
+      fts5BufferSafeAppendVarint(&out, (tmp.n+nTail) * 2);
+      fts5BufferSafeAppendBlob(&out, tmp.p, tmp.n);
+      if( nTail>0 ){
+        fts5BufferSafeAppendBlob(&out, &pHead->aPos[pHead->iOff], nTail);
+      }
+
+      pHead = pSave;
+      for(i=0; i<nBuf+1; i++){
+        PrefixMerger *pX = &aMerger[i];
+        if( pX->iter.aPoslist && pX->iter.iRowid==iLastRowid ){
+          fts5DoclistIterNext(&pX->iter);
+          fts5PrefixMergerInsertByRowid(&pHead, pX);
+        }
+      }
+
+    }else{
+      /* Copy poslist from pHead to output */
+      PrefixMerger *pThis = pHead;
+      Fts5DoclistIter *pI = &pThis->iter;
+      fts5BufferSafeAppendBlob(&out, pI->aPoslist, pI->nPoslist+pI->nSize);
+      fts5DoclistIterNext(pI);
+      pHead = pThis->pNext;
+      fts5PrefixMergerInsertByRowid(&pHead, pThis);
+    }
+  }
+
+  fts5BufferFree(p1);
+  fts5BufferFree(&tmp);
+  memset(&out.p[out.n], 0, FTS5_DATA_ZERO_PADDING);
+  *p1 = out;
+}
+
+
+/*
+** Iterate through a range of entries in the FTS index, invoking the xVisit
+** callback for each of them.
+**
+** Parameter pToken points to an nToken buffer containing an FTS index term
+** (i.e. a document term with the preceding 1 byte index identifier -
+** FTS5_MAIN_PREFIX or similar). If bPrefix is true, then the call visits
+** all entries for terms that have pToken/nToken as a prefix. If bPrefix
+** is false, then only entries with pToken/nToken as the entire key are
+** visited.
+**
+** If the current table is a tokendata=1 table, then if bPrefix is true then
+** each index term is treated separately. However, if bPrefix is false, then
+** all index terms corresponding to pToken/nToken are collapsed into a single
+** term before the callback is invoked.
+**
+** The callback invoked for each entry visited is specified by paramter xVisit.
+** Each time it is invoked, it is passed a pointer to the Fts5Index object,
+** a copy of the 7th paramter to this function (pCtx) and a pointer to the
+** iterator that indicates the current entry. If the current entry is the
+** first with a new term (i.e. different from that of the previous entry,
+** including the very first term), then the final two parameters are passed
+** a pointer to the term and its size in bytes, respectively. If the current
+** entry is not the first associated with its term, these two parameters
+** are passed 0.
+**
+** If parameter pColset is not NULL, then it is used to filter entries before
+** the callback is invoked.
+*/
+static int fts5VisitEntries(
+  Fts5Index *p,                   /* Fts5 index object */
+  Fts5Colset *pColset,            /* Columns filter to apply, or NULL */
+  u8 *pToken,                     /* Buffer containing token */
+  int nToken,                     /* Size of buffer pToken in bytes */
+  int bPrefix,                    /* True for a prefix scan */
+  void (*xVisit)(Fts5Index*, void *pCtx, Fts5Iter *pIter, const u8*, int),
+  void *pCtx                      /* Passed as second argument to xVisit() */
+){
+  const int flags = (bPrefix ? FTS5INDEX_QUERY_SCAN : 0)
+                  | FTS5INDEX_QUERY_SKIPEMPTY
+                  | FTS5INDEX_QUERY_NOOUTPUT;
+  Fts5Iter *p1 = 0;     /* Iterator used to gather data from index */
+  int bNewTerm = 1;
+  Fts5Structure *pStruct = fts5StructureRead(p);
+
+  fts5MultiIterNew(p, pStruct, flags, pColset, pToken, nToken, -1, 0, &p1);
+  fts5IterSetOutputCb(&p->rc, p1);
+  for( /* no-op */ ;
+      fts5MultiIterEof(p, p1)==0;
+      fts5MultiIterNext2(p, p1, &bNewTerm)
+  ){
+    Fts5SegIter *pSeg = &p1->aSeg[ p1->aFirst[1].iFirst ];
+    int nNew = 0;
+    const u8 *pNew = 0;
+
+    p1->xSetOutputs(p1, pSeg);
+    if( p->rc ) break;
+
+    if( bNewTerm ){
+      nNew = pSeg->term.n;
+      pNew = pSeg->term.p;
+      if( nNew<nToken || memcmp(pToken, pNew, nToken) ) break;
+    }
+
+    xVisit(p, pCtx, p1, pNew, nNew);
+  }
+  fts5MultiIterFree(p1);
+
+  fts5StructureRelease(pStruct);
+  return p->rc;
+}
+
+
+/*
+** Usually, a tokendata=1 iterator (struct Fts5TokenDataIter) accumulates an
+** array of these for each row it visits (so all iRowid fields are the same).
+** Or, for an iterator used by an "ORDER BY rank" query, it accumulates an
+** array of these for the entire query (in which case iRowid fields may take
+** a variety of values).
+**
+** Each instance in the array indicates the iterator (and therefore term)
+** associated with position iPos of rowid iRowid. This is used by the
+** xInstToken() API.
+**
+** iRowid:
+**   Rowid for the current entry.
+**
+** iPos:
+**   Position of current entry within row. In the usual ((iCol<<32)+iOff)
+**   format (e.g. see macros FTS5_POS2COLUMN() and FTS5_POS2OFFSET()).
+**
+** iIter:
+**   If the Fts5TokenDataIter iterator that the entry is part of is
+**   actually an iterator (i.e. with nIter>0, not just a container for
+**   Fts5TokenDataMap structures), then this variable is an index into
+**   the apIter[] array. The corresponding term is that which the iterator
+**   at apIter[iIter] currently points to.
+**
+**   Or, if the Fts5TokenDataIter iterator is just a container object
+**   (nIter==0), then iIter is an index into the term.p[] buffer where
+**   the term is stored.
+**
+** nByte:
+**   In the case where iIter is an index into term.p[], this variable
+**   is the size of the term in bytes. If iIter is an index into apIter[],
+**   this variable is unused.
+*/
+struct Fts5TokenDataMap {
+  i64 iRowid;                     /* Row this token is located in */
+  i64 iPos;                       /* Position of token */
+  int iIter;                      /* Iterator token was read from */
+  int nByte;                      /* Length of token in bytes (or 0) */
+};
+
+/*
+** An object used to supplement Fts5Iter for tokendata=1 iterators.
+**
+** This object serves two purposes. The first is as a container for an array
+** of Fts5TokenDataMap structures, which are used to find the token required
+** when the xInstToken() API is used. This is done by the nMapAlloc, nMap and
+** aMap[] variables.
+*/
+struct Fts5TokenDataIter {
+  int nMapAlloc;                  /* Allocated size of aMap[] in entries */
+  int nMap;                       /* Number of valid entries in aMap[] */
+  Fts5TokenDataMap *aMap;         /* Array of (rowid+pos -> token) mappings */
+
+  /* The following are used for prefix-queries only. */
+  Fts5Buffer terms;
+
+  /* The following are used for other full-token tokendata queries only. */
+  int nIter;
+  int nIterAlloc;
+  Fts5PoslistReader *aPoslistReader;
+  int *aPoslistToIter;
+  Fts5Iter *apIter[1];
+};
+
+/*
+** The two input arrays - a1[] and a2[] - are in sorted order. This function
+** merges the two arrays together and writes the result to output array
+** aOut[]. aOut[] is guaranteed to be large enough to hold the result.
+**
+** Duplicate entries are copied into the output. So the size of the output
+** array is always (n1+n2) entries.
+*/
+static void fts5TokendataMerge(
+  Fts5TokenDataMap *a1, int n1,   /* Input array 1 */
+  Fts5TokenDataMap *a2, int n2,   /* Input array 2 */
+  Fts5TokenDataMap *aOut          /* Output array */
+){
+  int i1 = 0;
+  int i2 = 0;
+
+  assert( n1>=0 && n2>=0 );
+  while( i1<n1 || i2<n2 ){
+    Fts5TokenDataMap *pOut = &aOut[i1+i2];
+    if( i2>=n2 || (i1<n1 && (
+        a1[i1].iRowid<a2[i2].iRowid
+     || (a1[i1].iRowid==a2[i2].iRowid && a1[i1].iPos<=a2[i2].iPos)
+    ))){
+      memcpy(pOut, &a1[i1], sizeof(Fts5TokenDataMap));
+      i1++;
+    }else{
+      memcpy(pOut, &a2[i2], sizeof(Fts5TokenDataMap));
+      i2++;
+    }
+  }
+}
+
+
+/*
+** Append a mapping to the token-map belonging to object pT.
+*/
+static void fts5TokendataIterAppendMap(
+  Fts5Index *p,
+  Fts5TokenDataIter *pT,
+  int iIter,
+  int nByte,
+  i64 iRowid,
+  i64 iPos
+){
+  if( p->rc==SQLITE_OK ){
+    if( pT->nMap==pT->nMapAlloc ){
+      int nNew = pT->nMapAlloc ? pT->nMapAlloc*2 : 64;
+      int nAlloc = nNew * sizeof(Fts5TokenDataMap);
+      Fts5TokenDataMap *aNew;
+
+      aNew = (Fts5TokenDataMap*)sqlite3_realloc(pT->aMap, nAlloc);
+      if( aNew==0 ){
+        p->rc = SQLITE_NOMEM;
+        return;
+      }
+
+      pT->aMap = aNew;
+      pT->nMapAlloc = nNew;
+    }
+
+    pT->aMap[pT->nMap].iRowid = iRowid;
+    pT->aMap[pT->nMap].iPos = iPos;
+    pT->aMap[pT->nMap].iIter = iIter;
+    pT->aMap[pT->nMap].nByte = nByte;
+    pT->nMap++;
+  }
+}
+
+/*
+** Sort the contents of the pT->aMap[] array.
+**
+** The sorting algorithm requries a malloc(). If this fails, an error code
+** is left in Fts5Index.rc before returning.
+*/
+static void fts5TokendataIterSortMap(Fts5Index *p, Fts5TokenDataIter *pT){
+  Fts5TokenDataMap *aTmp = 0;
+  int nByte = pT->nMap * sizeof(Fts5TokenDataMap);
+
+  aTmp = (Fts5TokenDataMap*)sqlite3Fts5MallocZero(&p->rc, nByte);
+  if( aTmp ){
+    Fts5TokenDataMap *a1 = pT->aMap;
+    Fts5TokenDataMap *a2 = aTmp;
+    i64 nHalf;
+
+    for(nHalf=1; nHalf<pT->nMap; nHalf=nHalf*2){
+      int i1;
+      for(i1=0; i1<pT->nMap; i1+=(nHalf*2)){
+        int n1 = MIN(nHalf, pT->nMap-i1);
+        int n2 = MIN(nHalf, pT->nMap-i1-n1);
+        fts5TokendataMerge(&a1[i1], n1, &a1[i1+n1], n2, &a2[i1]);
+      }
+      SWAPVAL(Fts5TokenDataMap*, a1, a2);
+    }
+
+    if( a1!=pT->aMap ){
+      memcpy(pT->aMap, a1, pT->nMap*sizeof(Fts5TokenDataMap));
+    }
+    sqlite3_free(aTmp);
+
+#ifdef SQLITE_DEBUG
+    {
+      int ii;
+      for(ii=1; ii<pT->nMap; ii++){
+        Fts5TokenDataMap *p1 = &pT->aMap[ii-1];
+        Fts5TokenDataMap *p2 = &pT->aMap[ii];
+        assert( p1->iRowid<p2->iRowid
+             || (p1->iRowid==p2->iRowid && p1->iPos<=p2->iPos)
+        );
+      }
+    }
+#endif
+  }
+}
+
+/*
+** Delete an Fts5TokenDataIter structure and its contents.
+*/
+static void fts5TokendataIterDelete(Fts5TokenDataIter *pSet){
+  if( pSet ){
+    int ii;
+    for(ii=0; ii<pSet->nIter; ii++){
+      fts5MultiIterFree(pSet->apIter[ii]);
+    }
+    fts5BufferFree(&pSet->terms);
+    sqlite3_free(pSet->aPoslistReader);
+    sqlite3_free(pSet->aMap);
+    sqlite3_free(pSet);
+  }
+}
+
+
+/*
+** fts5VisitEntries() context object used by fts5SetupPrefixIterTokendata()
+** to pass data to prefixIterSetupTokendataCb().
+*/
+typedef struct TokendataSetupCtx TokendataSetupCtx;
+struct TokendataSetupCtx {
+  Fts5TokenDataIter *pT;          /* Object being populated with mappings */
+  int iTermOff;                   /* Offset of current term in terms.p[] */
+  int nTermByte;                  /* Size of current term in bytes */
+};
+
+/*
+** fts5VisitEntries() callback used by fts5SetupPrefixIterTokendata(). This
+** callback adds an entry to the Fts5TokenDataIter.aMap[] array for each
+** position in the current position-list. It doesn't matter that some of
+** these may be out of order - they will be sorted later.
+*/
+static void prefixIterSetupTokendataCb(
+  Fts5Index *p,
+  void *pCtx,
+  Fts5Iter *p1,
+  const u8 *pNew,
+  int nNew
+){
+  TokendataSetupCtx *pSetup = (TokendataSetupCtx*)pCtx;
+  int iPosOff = 0;
+  i64 iPos = 0;
+
+  if( pNew ){
+    pSetup->nTermByte = nNew-1;
+    pSetup->iTermOff = pSetup->pT->terms.n;
+    fts5BufferAppendBlob(&p->rc, &pSetup->pT->terms, nNew-1, pNew+1);
+  }
+
+  while( 0==sqlite3Fts5PoslistNext64(
+     p1->base.pData, p1->base.nData, &iPosOff, &iPos
+  ) ){
+    fts5TokendataIterAppendMap(p,
+        pSetup->pT, pSetup->iTermOff, pSetup->nTermByte, p1->base.iRowid, iPos
+    );
+  }
+}
+
+
+/*
+** Context object passed by fts5SetupPrefixIter() to fts5VisitEntries().
+*/
+typedef struct PrefixSetupCtx PrefixSetupCtx;
+struct PrefixSetupCtx {
+  void (*xMerge)(Fts5Index*, Fts5Buffer*, int, Fts5Buffer*);
+  void (*xAppend)(Fts5Index*, u64, Fts5Iter*, Fts5Buffer*);
+  i64 iLastRowid;
+  int nMerge;
+  Fts5Buffer *aBuf;
+  int nBuf;
+  Fts5Buffer doclist;
+  TokendataSetupCtx *pTokendata;
+};
+
+/*
+** fts5VisitEntries() callback used by fts5SetupPrefixIter()
+*/
+static void prefixIterSetupCb(
+  Fts5Index *p,
+  void *pCtx,
+  Fts5Iter *p1,
+  const u8 *pNew,
+  int nNew
+){
+  PrefixSetupCtx *pSetup = (PrefixSetupCtx*)pCtx;
+  const int nMerge = pSetup->nMerge;
+
+  if( p1->base.nData>0 ){
+    if( p1->base.iRowid<=pSetup->iLastRowid && pSetup->doclist.n>0 ){
+      int i;
+      for(i=0; p->rc==SQLITE_OK && pSetup->doclist.n; i++){
+        int i1 = i*nMerge;
+        int iStore;
+        assert( i1+nMerge<=pSetup->nBuf );
+        for(iStore=i1; iStore<i1+nMerge; iStore++){
+          if( pSetup->aBuf[iStore].n==0 ){
+            fts5BufferSwap(&pSetup->doclist, &pSetup->aBuf[iStore]);
+            fts5BufferZero(&pSetup->doclist);
+            break;
+          }
+        }
+        if( iStore==i1+nMerge ){
+          pSetup->xMerge(p, &pSetup->doclist, nMerge, &pSetup->aBuf[i1]);
+          for(iStore=i1; iStore<i1+nMerge; iStore++){
+            fts5BufferZero(&pSetup->aBuf[iStore]);
+          }
+        }
+      }
+      pSetup->iLastRowid = 0;
+    }
+
+    pSetup->xAppend(
+        p, (u64)p1->base.iRowid-(u64)pSetup->iLastRowid, p1, &pSetup->doclist
+    );
+    pSetup->iLastRowid = p1->base.iRowid;
+  }
+
+  if( pSetup->pTokendata ){
+    prefixIterSetupTokendataCb(p, (void*)pSetup->pTokendata, p1, pNew, nNew);
+  }
+}
+
+static void fts5SetupPrefixIter(
+  Fts5Index *p,                   /* Index to read from */
+  int bDesc,                      /* True for "ORDER BY rowid DESC" */
+  int iIdx,                       /* Index to scan for data */
+  u8 *pToken,                     /* Buffer containing prefix to match */
+  int nToken,                     /* Size of buffer pToken in bytes */
+  Fts5Colset *pColset,            /* Restrict matches to these columns */
+  Fts5Iter **ppIter               /* OUT: New iterator */
+){
+  Fts5Structure *pStruct;
+  PrefixSetupCtx s;
+  TokendataSetupCtx s2;
+
+  memset(&s, 0, sizeof(s));
+  memset(&s2, 0, sizeof(s2));
+
+  s.nMerge = 1;
+  s.iLastRowid = 0;
+  s.nBuf = 32;
+  if( iIdx==0
+   && p->pConfig->eDetail==FTS5_DETAIL_FULL
+   && p->pConfig->bPrefixInsttoken
+  ){
+    s.pTokendata = &s2;
+    s2.pT = (Fts5TokenDataIter*)fts5IdxMalloc(p, sizeof(*s2.pT));
+  }
+
+  if( p->pConfig->eDetail==FTS5_DETAIL_NONE ){
+    s.xMerge = fts5MergeRowidLists;
+    s.xAppend = fts5AppendRowid;
+  }else{
+    s.nMerge = FTS5_MERGE_NLIST-1;
+    s.nBuf = s.nMerge*8;   /* Sufficient to merge (16^8)==(2^32) lists */
+    s.xMerge = fts5MergePrefixLists;
+    s.xAppend = fts5AppendPoslist;
+  }
+
+  s.aBuf = (Fts5Buffer*)fts5IdxMalloc(p, sizeof(Fts5Buffer)*s.nBuf);
+  pStruct = fts5StructureRead(p);
+  assert( p->rc!=SQLITE_OK || (s.aBuf && pStruct) );
+
+  if( p->rc==SQLITE_OK ){
+    void *pCtx = (void*)&s;
+    int i;
+    Fts5Data *pData;
+
+    /* If iIdx is non-zero, then it is the number of a prefix-index for
+    ** prefixes 1 character longer than the prefix being queried for. That
+    ** index contains all the doclists required, except for the one
+    ** corresponding to the prefix itself. That one is extracted from the
+    ** main term index here.  */
+    if( iIdx!=0 ){
+      pToken[0] = FTS5_MAIN_PREFIX;
+      fts5VisitEntries(p, pColset, pToken, nToken, 0, prefixIterSetupCb, pCtx);
+    }
+
+    pToken[0] = FTS5_MAIN_PREFIX + iIdx;
+    fts5VisitEntries(p, pColset, pToken, nToken, 1, prefixIterSetupCb, pCtx);
+
+    assert( (s.nBuf%s.nMerge)==0 );
+    for(i=0; i<s.nBuf; i+=s.nMerge){
+      int iFree;
+      if( p->rc==SQLITE_OK ){
+        s.xMerge(p, &s.doclist, s.nMerge, &s.aBuf[i]);
+      }
+      for(iFree=i; iFree<i+s.nMerge; iFree++){
+        fts5BufferFree(&s.aBuf[iFree]);
+      }
+    }
+
+    pData = fts5IdxMalloc(p, sizeof(*pData)+s.doclist.n+FTS5_DATA_ZERO_PADDING);
+    assert( pData!=0 || p->rc!=SQLITE_OK );
+    if( pData ){
+      pData->p = (u8*)&pData[1];
+      pData->nn = pData->szLeaf = s.doclist.n;
+      if( s.doclist.n ) memcpy(pData->p, s.doclist.p, s.doclist.n);
+      fts5MultiIterNew2(p, pData, bDesc, ppIter);
+    }
+
+    assert( (*ppIter)!=0 || p->rc!=SQLITE_OK );
+    if( p->rc==SQLITE_OK && s.pTokendata ){
+      fts5TokendataIterSortMap(p, s2.pT);
+      (*ppIter)->pTokenDataIter = s2.pT;
+      s2.pT = 0;
+    }
+  }
+
+  fts5TokendataIterDelete(s2.pT);
+  fts5BufferFree(&s.doclist);
+  fts5StructureRelease(pStruct);
+  sqlite3_free(s.aBuf);
+}
+
+
+/*
+** Indicate that all subsequent calls to sqlite3Fts5IndexWrite() pertain
+** to the document with rowid iRowid.
+*/
+static int sqlite3Fts5IndexBeginWrite(Fts5Index *p, int bDelete, i64 iRowid){
+  assert( p->rc==SQLITE_OK );
+
+  /* Allocate the hash table if it has not already been allocated */
+  if( p->pHash==0 ){
+    p->rc = sqlite3Fts5HashNew(p->pConfig, &p->pHash, &p->nPendingData);
+  }
+
+  /* Flush the hash table to disk if required */
+  if( iRowid<p->iWriteRowid
+   || (iRowid==p->iWriteRowid && p->bDelete==0)
+   || (p->nPendingData > p->pConfig->nHashSize)
+  ){
+    fts5IndexFlush(p);
+  }
+
+  p->iWriteRowid = iRowid;
+  p->bDelete = bDelete;
+  if( bDelete==0 ){
+    p->nPendingRow++;
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** Commit data to disk.
+*/
+static int sqlite3Fts5IndexSync(Fts5Index *p){
+  assert( p->rc==SQLITE_OK );
+  fts5IndexFlush(p);
+  fts5IndexCloseReader(p);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Discard any data stored in the in-memory hash tables. Do not write it
+** to the database. Additionally, assume that the contents of the %_data
+** table may have changed on disk. So any in-memory caches of %_data
+** records must be invalidated.
+*/
+static int sqlite3Fts5IndexRollback(Fts5Index *p){
+  fts5IndexCloseReader(p);
+  fts5IndexDiscardData(p);
+  fts5StructureInvalidate(p);
+  return fts5IndexReturn(p);
+}
+
+/*
+** The %_data table is completely empty when this function is called. This
+** function populates it with the initial structure objects for each index,
+** and the initial version of the "averages" record (a zero-byte blob).
+*/
+static int sqlite3Fts5IndexReinit(Fts5Index *p){
+  Fts5Structure s;
+  fts5StructureInvalidate(p);
+  fts5IndexDiscardData(p);
+  memset(&s, 0, sizeof(Fts5Structure));
+  if( p->pConfig->bContentlessDelete ){
+    s.nOriginCntr = 1;
+  }
+  fts5DataWrite(p, FTS5_AVERAGES_ROWID, (const u8*)"", 0);
+  fts5StructureWrite(p, &s);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Open a new Fts5Index handle. If the bCreate argument is true, create
+** and initialize the underlying %_data table.
+**
+** If successful, set *pp to point to the new object and return SQLITE_OK.
+** Otherwise, set *pp to NULL and return an SQLite error code.
+*/
+static int sqlite3Fts5IndexOpen(
+  Fts5Config *pConfig,
+  int bCreate,
+  Fts5Index **pp,
+  char **pzErr
+){
+  int rc = SQLITE_OK;
+  Fts5Index *p;                   /* New object */
+
+  *pp = p = (Fts5Index*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Index));
+  if( rc==SQLITE_OK ){
+    p->pConfig = pConfig;
+    p->nWorkUnit = FTS5_WORK_UNIT;
+    p->zDataTbl = sqlite3Fts5Mprintf(&rc, "%s_data", pConfig->zName);
+    if( p->zDataTbl && bCreate ){
+      rc = sqlite3Fts5CreateTable(
+          pConfig, "data", "id INTEGER PRIMARY KEY, block BLOB", 0, pzErr
+      );
+      if( rc==SQLITE_OK ){
+        rc = sqlite3Fts5CreateTable(pConfig, "idx",
+            "segid, term, pgno, PRIMARY KEY(segid, term)",
+            1, pzErr
+        );
+      }
+      if( rc==SQLITE_OK ){
+        rc = sqlite3Fts5IndexReinit(p);
+      }
+    }
+  }
+
+  assert( rc!=SQLITE_OK || p->rc==SQLITE_OK );
+  if( rc ){
+    sqlite3Fts5IndexClose(p);
+    *pp = 0;
+  }
+  return rc;
+}
+
+/*
+** Close a handle opened by an earlier call to sqlite3Fts5IndexOpen().
+*/
+static int sqlite3Fts5IndexClose(Fts5Index *p){
+  int rc = SQLITE_OK;
+  if( p ){
+    assert( p->pReader==0 );
+    fts5StructureInvalidate(p);
+    sqlite3_finalize(p->pWriter);
+    sqlite3_finalize(p->pDeleter);
+    sqlite3_finalize(p->pIdxWriter);
+    sqlite3_finalize(p->pIdxDeleter);
+    sqlite3_finalize(p->pIdxSelect);
+    sqlite3_finalize(p->pIdxNextSelect);
+    sqlite3_finalize(p->pDataVersion);
+    sqlite3_finalize(p->pDeleteFromIdx);
+    sqlite3Fts5HashFree(p->pHash);
+    sqlite3_free(p->zDataTbl);
+    sqlite3_free(p);
+  }
+  return rc;
+}
+
+/*
+** Argument p points to a buffer containing utf-8 text that is n bytes in
+** size. Return the number of bytes in the nChar character prefix of the
+** buffer, or 0 if there are less than nChar characters in total.
+*/
+static int sqlite3Fts5IndexCharlenToBytelen(
+  const char *p,
+  int nByte,
+  int nChar
+){
+  int n = 0;
+  int i;
+  for(i=0; i<nChar; i++){
+    if( n>=nByte ) return 0;      /* Input contains fewer than nChar chars */
+    if( (unsigned char)p[n++]>=0xc0 ){
+      if( n>=nByte ) return 0;
+      while( (p[n] & 0xc0)==0x80 ){
+        n++;
+        if( n>=nByte ){
+          if( i+1==nChar ) break;
+          return 0;
+        }
+      }
+    }
+  }
+  return n;
+}
+
+/*
+** pIn is a UTF-8 encoded string, nIn bytes in size. Return the number of
+** unicode characters in the string.
+*/
+static int fts5IndexCharlen(const char *pIn, int nIn){
+  int nChar = 0;
+  int i = 0;
+  while( i<nIn ){
+    if( (unsigned char)pIn[i++]>=0xc0 ){
+      while( i<nIn && (pIn[i] & 0xc0)==0x80 ) i++;
+    }
+    nChar++;
+  }
+  return nChar;
+}
+
+/*
+** Insert or remove data to or from the index. Each time a document is
+** added to or removed from the index, this function is called one or more
+** times.
+**
+** For an insert, it must be called once for each token in the new document.
+** If the operation is a delete, it must be called (at least) once for each
+** unique token in the document with an iCol value less than zero. The iPos
+** argument is ignored for a delete.
+*/
+static int sqlite3Fts5IndexWrite(
+  Fts5Index *p,                   /* Index to write to */
+  int iCol,                       /* Column token appears in (-ve -> delete) */
+  int iPos,                       /* Position of token within column */
+  const char *pToken, int nToken  /* Token to add or remove to or from index */
+){
+  int i;                          /* Used to iterate through indexes */
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5Config *pConfig = p->pConfig;
+
+  assert( p->rc==SQLITE_OK );
+  assert( (iCol<0)==p->bDelete );
+
+  /* Add the entry to the main terms index. */
+  rc = sqlite3Fts5HashWrite(
+      p->pHash, p->iWriteRowid, iCol, iPos, FTS5_MAIN_PREFIX, pToken, nToken
+  );
+
+  for(i=0; i<pConfig->nPrefix && rc==SQLITE_OK; i++){
+    const int nChar = pConfig->aPrefix[i];
+    int nByte = sqlite3Fts5IndexCharlenToBytelen(pToken, nToken, nChar);
+    if( nByte ){
+      rc = sqlite3Fts5HashWrite(p->pHash,
+          p->iWriteRowid, iCol, iPos, (char)(FTS5_MAIN_PREFIX+i+1), pToken,
+          nByte
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** pToken points to a buffer of size nToken bytes containing a search
+** term, including the index number at the start, used on a tokendata=1
+** table. This function returns true if the term in buffer pBuf matches
+** token pToken/nToken.
+*/
+static int fts5IsTokendataPrefix(
+  Fts5Buffer *pBuf,
+  const u8 *pToken,
+  int nToken
+){
+  return (
+      pBuf->n>=nToken
+   && 0==memcmp(pBuf->p, pToken, nToken)
+   && (pBuf->n==nToken || pBuf->p[nToken]==0x00)
+  );
+}
+
+/*
+** Ensure the segment-iterator passed as the only argument points to EOF.
+*/
+static void fts5SegIterSetEOF(Fts5SegIter *pSeg){
+  fts5DataRelease(pSeg->pLeaf);
+  pSeg->pLeaf = 0;
+}
+
+static void fts5IterClose(Fts5IndexIter *pIndexIter){
+  if( pIndexIter ){
+    Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+    Fts5Index *pIndex = pIter->pIndex;
+    fts5TokendataIterDelete(pIter->pTokenDataIter);
+    fts5MultiIterFree(pIter);
+    fts5IndexCloseReader(pIndex);
+  }
+}
+
+/*
+** This function appends iterator pAppend to Fts5TokenDataIter pIn and
+** returns the result.
+*/
+static Fts5TokenDataIter *fts5AppendTokendataIter(
+  Fts5Index *p,                   /* Index object (for error code) */
+  Fts5TokenDataIter *pIn,         /* Current Fts5TokenDataIter struct */
+  Fts5Iter *pAppend               /* Append this iterator */
+){
+  Fts5TokenDataIter *pRet = pIn;
+
+  if( p->rc==SQLITE_OK ){
+    if( pIn==0 || pIn->nIter==pIn->nIterAlloc ){
+      int nAlloc = pIn ? pIn->nIterAlloc*2 : 16;
+      int nByte = nAlloc * sizeof(Fts5Iter*) + sizeof(Fts5TokenDataIter);
+      Fts5TokenDataIter *pNew = (Fts5TokenDataIter*)sqlite3_realloc(pIn, nByte);
+
+      if( pNew==0 ){
+        p->rc = SQLITE_NOMEM;
+      }else{
+        if( pIn==0 ) memset(pNew, 0, nByte);
+        pRet = pNew;
+        pNew->nIterAlloc = nAlloc;
+      }
+    }
+  }
+  if( p->rc ){
+    fts5IterClose((Fts5IndexIter*)pAppend);
+  }else{
+    pRet->apIter[pRet->nIter++] = pAppend;
+  }
+  assert( pRet==0 || pRet->nIter<=pRet->nIterAlloc );
+
+  return pRet;
+}
+
+/*
+** The iterator passed as the only argument must be a tokendata=1 iterator
+** (pIter->pTokenDataIter!=0). This function sets the iterator output
+** variables (pIter->base.*) according to the contents of the current
+** row.
+*/
+static void fts5IterSetOutputsTokendata(Fts5Iter *pIter){
+  int ii;
+  int nHit = 0;
+  i64 iRowid = SMALLEST_INT64;
+  int iMin = 0;
+
+  Fts5TokenDataIter *pT = pIter->pTokenDataIter;
+
+  pIter->base.nData = 0;
+  pIter->base.pData = 0;
+
+  for(ii=0; ii<pT->nIter; ii++){
+    Fts5Iter *p = pT->apIter[ii];
+    if( p->base.bEof==0 ){
+      if( nHit==0 || p->base.iRowid<iRowid ){
+        iRowid = p->base.iRowid;
+        nHit = 1;
+        pIter->base.pData = p->base.pData;
+        pIter->base.nData = p->base.nData;
+        iMin = ii;
+      }else if( p->base.iRowid==iRowid ){
+        nHit++;
+      }
+    }
+  }
+
+  if( nHit==0 ){
+    pIter->base.bEof = 1;
+  }else{
+    int eDetail = pIter->pIndex->pConfig->eDetail;
+    pIter->base.bEof = 0;
+    pIter->base.iRowid = iRowid;
+
+    if( nHit==1 && eDetail==FTS5_DETAIL_FULL ){
+      fts5TokendataIterAppendMap(pIter->pIndex, pT, iMin, 0, iRowid, -1);
+    }else
+    if( nHit>1 && eDetail!=FTS5_DETAIL_NONE ){
+      int nReader = 0;
+      int nByte = 0;
+      i64 iPrev = 0;
+
+      /* Allocate array of iterators if they are not already allocated. */
+      if( pT->aPoslistReader==0 ){
+        pT->aPoslistReader = (Fts5PoslistReader*)sqlite3Fts5MallocZero(
+            &pIter->pIndex->rc,
+            pT->nIter * (sizeof(Fts5PoslistReader) + sizeof(int))
+        );
+        if( pT->aPoslistReader==0 ) return;
+        pT->aPoslistToIter = (int*)&pT->aPoslistReader[pT->nIter];
+      }
+
+      /* Populate an iterator for each poslist that will be merged */
+      for(ii=0; ii<pT->nIter; ii++){
+        Fts5Iter *p = pT->apIter[ii];
+        if( iRowid==p->base.iRowid ){
+          pT->aPoslistToIter[nReader] = ii;
+          sqlite3Fts5PoslistReaderInit(
+              p->base.pData, p->base.nData, &pT->aPoslistReader[nReader++]
+          );
+          nByte += p->base.nData;
+        }
+      }
+
+      /* Ensure the output buffer is large enough */
+      if( fts5BufferGrow(&pIter->pIndex->rc, &pIter->poslist, nByte+nHit*10) ){
+        return;
+      }
+
+      /* Ensure the token-mapping is large enough */
+      if( eDetail==FTS5_DETAIL_FULL && pT->nMapAlloc<(pT->nMap + nByte) ){
+        int nNew = (pT->nMapAlloc + nByte) * 2;
+        Fts5TokenDataMap *aNew = (Fts5TokenDataMap*)sqlite3_realloc(
+            pT->aMap, nNew*sizeof(Fts5TokenDataMap)
+        );
+        if( aNew==0 ){
+          pIter->pIndex->rc = SQLITE_NOMEM;
+          return;
+        }
+        pT->aMap = aNew;
+        pT->nMapAlloc = nNew;
+      }
+
+      pIter->poslist.n = 0;
+
+      while( 1 ){
+        i64 iMinPos = LARGEST_INT64;
+
+        /* Find smallest position */
+        iMin = 0;
+        for(ii=0; ii<nReader; ii++){
+          Fts5PoslistReader *pReader = &pT->aPoslistReader[ii];
+          if( pReader->bEof==0 ){
+            if( pReader->iPos<iMinPos ){
+              iMinPos = pReader->iPos;
+              iMin = ii;
+            }
+          }
+        }
+
+        /* If all readers were at EOF, break out of the loop. */
+        if( iMinPos==LARGEST_INT64 ) break;
+
+        sqlite3Fts5PoslistSafeAppend(&pIter->poslist, &iPrev, iMinPos);
+        sqlite3Fts5PoslistReaderNext(&pT->aPoslistReader[iMin]);
+
+        if( eDetail==FTS5_DETAIL_FULL ){
+          pT->aMap[pT->nMap].iPos = iMinPos;
+          pT->aMap[pT->nMap].iIter = pT->aPoslistToIter[iMin];
+          pT->aMap[pT->nMap].iRowid = iRowid;
+          pT->nMap++;
+        }
+      }
+
+      pIter->base.pData = pIter->poslist.p;
+      pIter->base.nData = pIter->poslist.n;
+    }
+  }
+}
+
+/*
+** The iterator passed as the only argument must be a tokendata=1 iterator
+** (pIter->pTokenDataIter!=0). This function advances the iterator. If
+** argument bFrom is false, then the iterator is advanced to the next
+** entry. Or, if bFrom is true, it is advanced to the first entry with
+** a rowid of iFrom or greater.
+*/
+static void fts5TokendataIterNext(Fts5Iter *pIter, int bFrom, i64 iFrom){
+  int ii;
+  Fts5TokenDataIter *pT = pIter->pTokenDataIter;
+  Fts5Index *pIndex = pIter->pIndex;
+
+  for(ii=0; ii<pT->nIter; ii++){
+    Fts5Iter *p = pT->apIter[ii];
+    if( p->base.bEof==0
+     && (p->base.iRowid==pIter->base.iRowid || (bFrom && p->base.iRowid<iFrom))
+    ){
+      fts5MultiIterNext(pIndex, p, bFrom, iFrom);
+      while( bFrom && p->base.bEof==0
+          && p->base.iRowid<iFrom
+          && pIndex->rc==SQLITE_OK
+      ){
+        fts5MultiIterNext(pIndex, p, 0, 0);
+      }
+    }
+  }
+
+  if( pIndex->rc==SQLITE_OK ){
+    fts5IterSetOutputsTokendata(pIter);
+  }
+}
+
+/*
+** If the segment-iterator passed as the first argument is at EOF, then
+** set pIter->term to a copy of buffer pTerm.
+*/
+static void fts5TokendataSetTermIfEof(Fts5Iter *pIter, Fts5Buffer *pTerm){
+  if( pIter && pIter->aSeg[0].pLeaf==0 ){
+    fts5BufferSet(&pIter->pIndex->rc, &pIter->aSeg[0].term, pTerm->n, pTerm->p);
+  }
+}
+
+/*
+** This function sets up an iterator to use for a non-prefix query on a
+** tokendata=1 table.
+*/
+static Fts5Iter *fts5SetupTokendataIter(
+  Fts5Index *p,                   /* FTS index to query */
+  const u8 *pToken,               /* Buffer containing query term */
+  int nToken,                     /* Size of buffer pToken in bytes */
+  Fts5Colset *pColset             /* Colset to filter on */
+){
+  Fts5Iter *pRet = 0;
+  Fts5TokenDataIter *pSet = 0;
+  Fts5Structure *pStruct = 0;
+  const int flags = FTS5INDEX_QUERY_SCANONETERM | FTS5INDEX_QUERY_SCAN;
+
+  Fts5Buffer bSeek = {0, 0, 0};
+  Fts5Buffer *pSmall = 0;
+
+  fts5IndexFlush(p);
+  pStruct = fts5StructureRead(p);
+
+  while( p->rc==SQLITE_OK ){
+    Fts5Iter *pPrev = pSet ? pSet->apIter[pSet->nIter-1] : 0;
+    Fts5Iter *pNew = 0;
+    Fts5SegIter *pNewIter = 0;
+    Fts5SegIter *pPrevIter = 0;
+
+    int iLvl, iSeg, ii;
+
+    pNew = fts5MultiIterAlloc(p, pStruct->nSegment);
+    if( pSmall ){
+      fts5BufferSet(&p->rc, &bSeek, pSmall->n, pSmall->p);
+      fts5BufferAppendBlob(&p->rc, &bSeek, 1, (const u8*)"\0");
+    }else{
+      fts5BufferSet(&p->rc, &bSeek, nToken, pToken);
+    }
+    if( p->rc ){
+      fts5IterClose((Fts5IndexIter*)pNew);
+      break;
+    }
+
+    pNewIter = &pNew->aSeg[0];
+    pPrevIter = (pPrev ? &pPrev->aSeg[0] : 0);
+    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+      for(iSeg=pStruct->aLevel[iLvl].nSeg-1; iSeg>=0; iSeg--){
+        Fts5StructureSegment *pSeg = &pStruct->aLevel[iLvl].aSeg[iSeg];
+        int bDone = 0;
+
+        if( pPrevIter ){
+          if( fts5BufferCompare(pSmall, &pPrevIter->term) ){
+            memcpy(pNewIter, pPrevIter, sizeof(Fts5SegIter));
+            memset(pPrevIter, 0, sizeof(Fts5SegIter));
+            bDone = 1;
+          }else if( pPrevIter->iEndofDoclist>pPrevIter->pLeaf->szLeaf ){
+            fts5SegIterNextInit(p,(const char*)bSeek.p,bSeek.n-1,pSeg,pNewIter);
+            bDone = 1;
+          }
+        }
+
+        if( bDone==0 ){
+          fts5SegIterSeekInit(p, bSeek.p, bSeek.n, flags, pSeg, pNewIter);
+        }
+
+        if( pPrevIter ){
+          if( pPrevIter->pTombArray ){
+            pNewIter->pTombArray = pPrevIter->pTombArray;
+            pNewIter->pTombArray->nRef++;
+          }
+        }else{
+          fts5SegIterAllocTombstone(p, pNewIter);
+        }
+
+        pNewIter++;
+        if( pPrevIter ) pPrevIter++;
+        if( p->rc ) break;
+      }
+    }
+    fts5TokendataSetTermIfEof(pPrev, pSmall);
+
+    pNew->bSkipEmpty = 1;
+    pNew->pColset = pColset;
+    fts5IterSetOutputCb(&p->rc, pNew);
+
+    /* Loop through all segments in the new iterator. Find the smallest
+    ** term that any segment-iterator points to. Iterator pNew will be
+    ** used for this term. Also, set any iterator that points to a term that
+    ** does not match pToken/nToken to point to EOF */
+    pSmall = 0;
+    for(ii=0; ii<pNew->nSeg; ii++){
+      Fts5SegIter *pII = &pNew->aSeg[ii];
+      if( 0==fts5IsTokendataPrefix(&pII->term, pToken, nToken) ){
+        fts5SegIterSetEOF(pII);
+      }
+      if( pII->pLeaf && (!pSmall || fts5BufferCompare(pSmall, &pII->term)>0) ){
+        pSmall = &pII->term;
+      }
+    }
+
+    /* If pSmall is still NULL at this point, then the new iterator does
+    ** not point to any terms that match the query. So delete it and break
+    ** out of the loop - all required iterators have been collected.  */
+    if( pSmall==0 ){
+      fts5IterClose((Fts5IndexIter*)pNew);
+      break;
+    }
+
+    /* Append this iterator to the set and continue. */
+    pSet = fts5AppendTokendataIter(p, pSet, pNew);
+  }
+
+  if( p->rc==SQLITE_OK && pSet ){
+    int ii;
+    for(ii=0; ii<pSet->nIter; ii++){
+      Fts5Iter *pIter = pSet->apIter[ii];
+      int iSeg;
+      for(iSeg=0; iSeg<pIter->nSeg; iSeg++){
+        pIter->aSeg[iSeg].flags |= FTS5_SEGITER_ONETERM;
+      }
+      fts5MultiIterFinishSetup(p, pIter);
+    }
+  }
+
+  if( p->rc==SQLITE_OK ){
+    pRet = fts5MultiIterAlloc(p, 0);
+  }
+  if( pRet ){
+    pRet->nSeg = 0;
+    pRet->pTokenDataIter = pSet;
+    if( pSet ){
+      fts5IterSetOutputsTokendata(pRet);
+    }else{
+      pRet->base.bEof = 1;
+    }
+  }else{
+    fts5TokendataIterDelete(pSet);
+  }
+
+  fts5StructureRelease(pStruct);
+  fts5BufferFree(&bSeek);
+  return pRet;
+}
+
+/*
+** Open a new iterator to iterate though all rowid that match the
+** specified token or token prefix.
+*/
+static int sqlite3Fts5IndexQuery(
+  Fts5Index *p,                   /* FTS index to query */
+  const char *pToken, int nToken, /* Token (or prefix) to query for */
+  int flags,                      /* Mask of FTS5INDEX_QUERY_X flags */
+  Fts5Colset *pColset,            /* Match these columns only */
+  Fts5IndexIter **ppIter          /* OUT: New iterator object */
+){
+  Fts5Config *pConfig = p->pConfig;
+  Fts5Iter *pRet = 0;
+  Fts5Buffer buf = {0, 0, 0};
+
+  /* If the QUERY_SCAN flag is set, all other flags must be clear. */
+  assert( (flags & FTS5INDEX_QUERY_SCAN)==0 || flags==FTS5INDEX_QUERY_SCAN );
+
+  if( sqlite3Fts5BufferSize(&p->rc, &buf, nToken+1)==0 ){
+    int iIdx = 0;                 /* Index to search */
+    int iPrefixIdx = 0;           /* +1 prefix index */
+    int bTokendata = pConfig->bTokendata;
+    assert( buf.p!=0 );
+    if( nToken>0 ) memcpy(&buf.p[1], pToken, nToken);
+
+    /* The NOTOKENDATA flag is set when each token in a tokendata=1 table
+    ** should be treated individually, instead of merging all those with
+    ** a common prefix into a single entry. This is used, for example, by
+    ** queries performed as part of an integrity-check, or by the fts5vocab
+    ** module.  */
+    if( flags & (FTS5INDEX_QUERY_NOTOKENDATA|FTS5INDEX_QUERY_SCAN) ){
+      bTokendata = 0;
+    }
+
+    /* Figure out which index to search and set iIdx accordingly. If this
+    ** is a prefix query for which there is no prefix index, set iIdx to
+    ** greater than pConfig->nPrefix to indicate that the query will be
+    ** satisfied by scanning multiple terms in the main index.
+    **
+    ** If the QUERY_TEST_NOIDX flag was specified, then this must be a
+    ** prefix-query. Instead of using a prefix-index (if one exists),
+    ** evaluate the prefix query using the main FTS index. This is used
+    ** for internal sanity checking by the integrity-check in debug
+    ** mode only.  */
+#ifdef SQLITE_DEBUG
+    if( pConfig->bPrefixIndex==0 || (flags & FTS5INDEX_QUERY_TEST_NOIDX) ){
+      assert( flags & FTS5INDEX_QUERY_PREFIX );
+      iIdx = 1+pConfig->nPrefix;
+    }else
+#endif
+    if( flags & FTS5INDEX_QUERY_PREFIX ){
+      int nChar = fts5IndexCharlen(pToken, nToken);
+      for(iIdx=1; iIdx<=pConfig->nPrefix; iIdx++){
+        int nIdxChar = pConfig->aPrefix[iIdx-1];
+        if( nIdxChar==nChar ) break;
+        if( nIdxChar==nChar+1 ) iPrefixIdx = iIdx;
+      }
+    }
+
+    if( bTokendata && iIdx==0 ){
+      buf.p[0] = FTS5_MAIN_PREFIX;
+      pRet = fts5SetupTokendataIter(p, buf.p, nToken+1, pColset);
+    }else if( iIdx<=pConfig->nPrefix ){
+      /* Straight index lookup */
+      Fts5Structure *pStruct = fts5StructureRead(p);
+      buf.p[0] = (u8)(FTS5_MAIN_PREFIX + iIdx);
+      if( pStruct ){
+        fts5MultiIterNew(p, pStruct, flags | FTS5INDEX_QUERY_SKIPEMPTY,
+            pColset, buf.p, nToken+1, -1, 0, &pRet
+        );
+        fts5StructureRelease(pStruct);
+      }
+    }else{
+      /* Scan multiple terms in the main index for a prefix query. */
+      int bDesc = (flags & FTS5INDEX_QUERY_DESC)!=0;
+      fts5SetupPrefixIter(p, bDesc, iPrefixIdx, buf.p, nToken+1, pColset,&pRet);
+      if( pRet==0 ){
+        assert( p->rc!=SQLITE_OK );
+      }else{
+        assert( pRet->pColset==0 );
+        fts5IterSetOutputCb(&p->rc, pRet);
+        if( p->rc==SQLITE_OK ){
+          Fts5SegIter *pSeg = &pRet->aSeg[pRet->aFirst[1].iFirst];
+          if( pSeg->pLeaf ) pRet->xSetOutputs(pRet, pSeg);
+        }
+      }
+    }
+
+    if( p->rc ){
+      fts5IterClose((Fts5IndexIter*)pRet);
+      pRet = 0;
+      fts5IndexCloseReader(p);
+    }
+
+    *ppIter = (Fts5IndexIter*)pRet;
+    sqlite3Fts5BufferFree(&buf);
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** Return true if the iterator passed as the only argument is at EOF.
+*/
+/*
+** Move to the next matching rowid.
+*/
+static int sqlite3Fts5IterNext(Fts5IndexIter *pIndexIter){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  assert( pIter->pIndex->rc==SQLITE_OK );
+  if( pIter->nSeg==0 ){
+    assert( pIter->pTokenDataIter );
+    fts5TokendataIterNext(pIter, 0, 0);
+  }else{
+    fts5MultiIterNext(pIter->pIndex, pIter, 0, 0);
+  }
+  return fts5IndexReturn(pIter->pIndex);
+}
+
+/*
+** Move to the next matching term/rowid. Used by the fts5vocab module.
+*/
+static int sqlite3Fts5IterNextScan(Fts5IndexIter *pIndexIter){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  Fts5Index *p = pIter->pIndex;
+
+  assert( pIter->pIndex->rc==SQLITE_OK );
+
+  fts5MultiIterNext(p, pIter, 0, 0);
+  if( p->rc==SQLITE_OK ){
+    Fts5SegIter *pSeg = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+    if( pSeg->pLeaf && pSeg->term.p[0]!=FTS5_MAIN_PREFIX ){
+      fts5DataRelease(pSeg->pLeaf);
+      pSeg->pLeaf = 0;
+      pIter->base.bEof = 1;
+    }
+  }
+
+  return fts5IndexReturn(pIter->pIndex);
+}
+
+/*
+** Move to the next matching rowid that occurs at or after iMatch. The
+** definition of "at or after" depends on whether this iterator iterates
+** in ascending or descending rowid order.
+*/
+static int sqlite3Fts5IterNextFrom(Fts5IndexIter *pIndexIter, i64 iMatch){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  if( pIter->nSeg==0 ){
+    assert( pIter->pTokenDataIter );
+    fts5TokendataIterNext(pIter, 1, iMatch);
+  }else{
+    fts5MultiIterNextFrom(pIter->pIndex, pIter, iMatch);
+  }
+  return fts5IndexReturn(pIter->pIndex);
+}
+
+/*
+** Return the current term.
+*/
+static const char *sqlite3Fts5IterTerm(Fts5IndexIter *pIndexIter, int *pn){
+  int n;
+  const char *z = (const char*)fts5MultiIterTerm((Fts5Iter*)pIndexIter, &n);
+  assert_nc( z || n<=1 );
+  *pn = n-1;
+  return (z ? &z[1] : 0);
+}
+
+/*
+** pIter is a prefix query. This function populates pIter->pTokenDataIter
+** with an Fts5TokenDataIter object containing mappings for all rows
+** matched by the query.
+*/
+static int fts5SetupPrefixIterTokendata(
+  Fts5Iter *pIter,
+  const char *pToken,             /* Token prefix to search for */
+  int nToken                      /* Size of pToken in bytes */
+){
+  Fts5Index *p = pIter->pIndex;
+  Fts5Buffer token = {0, 0, 0};
+  TokendataSetupCtx ctx;
+
+  memset(&ctx, 0, sizeof(ctx));
+
+  fts5BufferGrow(&p->rc, &token, nToken+1);
+  assert( token.p!=0 || p->rc!=SQLITE_OK );
+  ctx.pT = (Fts5TokenDataIter*)sqlite3Fts5MallocZero(&p->rc, sizeof(*ctx.pT));
+
+  if( p->rc==SQLITE_OK ){
+
+    /* Fill in the token prefix to search for */
+    token.p[0] = FTS5_MAIN_PREFIX;
+    memcpy(&token.p[1], pToken, nToken);
+    token.n = nToken+1;
+
+    fts5VisitEntries(
+        p, 0, token.p, token.n, 1, prefixIterSetupTokendataCb, (void*)&ctx
+    );
+
+    fts5TokendataIterSortMap(p, ctx.pT);
+  }
+
+  if( p->rc==SQLITE_OK ){
+    pIter->pTokenDataIter = ctx.pT;
+  }else{
+    fts5TokendataIterDelete(ctx.pT);
+  }
+  fts5BufferFree(&token);
+
+  return fts5IndexReturn(p);
+}
+
+/*
+** This is used by xInstToken() to access the token at offset iOff, column
+** iCol of row iRowid. The token is returned via output variables *ppOut
+** and *pnOut. The iterator passed as the first argument must be a tokendata=1
+** iterator (pIter->pTokenDataIter!=0).
+**
+** pToken/nToken:
+*/
+static int sqlite3Fts5IterToken(
+  Fts5IndexIter *pIndexIter,
+  const char *pToken, int nToken,
+  i64 iRowid,
+  int iCol,
+  int iOff,
+  const char **ppOut, int *pnOut
+){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  Fts5TokenDataIter *pT = pIter->pTokenDataIter;
+  i64 iPos = (((i64)iCol)<<32) + iOff;
+  Fts5TokenDataMap *aMap = 0;
+  int i1 = 0;
+  int i2 = 0;
+  int iTest = 0;
+
+  assert( pT || (pToken && pIter->nSeg>0) );
+  if( pT==0 ){
+    int rc = fts5SetupPrefixIterTokendata(pIter, pToken, nToken);
+    if( rc!=SQLITE_OK ) return rc;
+    pT = pIter->pTokenDataIter;
+  }
+
+  i2 = pT->nMap;
+  aMap = pT->aMap;
+
+  while( i2>i1 ){
+    iTest = (i1 + i2) / 2;
+
+    if( aMap[iTest].iRowid<iRowid ){
+      i1 = iTest+1;
+    }else if( aMap[iTest].iRowid>iRowid ){
+      i2 = iTest;
+    }else{
+      if( aMap[iTest].iPos<iPos ){
+        if( aMap[iTest].iPos<0 ){
+          break;
+        }
+        i1 = iTest+1;
+      }else if( aMap[iTest].iPos>iPos ){
+        i2 = iTest;
+      }else{
+        break;
+      }
+    }
+  }
+
+  if( i2>i1 ){
+    if( pIter->nSeg==0 ){
+      Fts5Iter *pMap = pT->apIter[aMap[iTest].iIter];
+      *ppOut = (const char*)pMap->aSeg[0].term.p+1;
+      *pnOut = pMap->aSeg[0].term.n-1;
+    }else{
+      Fts5TokenDataMap *p = &aMap[iTest];
+      *ppOut = (const char*)&pT->terms.p[p->iIter];
+      *pnOut = aMap[iTest].nByte;
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Clear any existing entries from the token-map associated with the
+** iterator passed as the only argument.
+*/
+static void sqlite3Fts5IndexIterClearTokendata(Fts5IndexIter *pIndexIter){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  if( pIter && pIter->pTokenDataIter
+   && (pIter->nSeg==0 || pIter->pIndex->pConfig->eDetail!=FTS5_DETAIL_FULL)
+  ){
+    pIter->pTokenDataIter->nMap = 0;
+  }
+}
+
+/*
+** Set a token-mapping for the iterator passed as the first argument. This
+** is used in detail=column or detail=none mode when a token is requested
+** using the xInstToken() API. In this case the caller tokenizers the
+** current row and configures the token-mapping via multiple calls to this
+** function.
+*/
+static int sqlite3Fts5IndexIterWriteTokendata(
+  Fts5IndexIter *pIndexIter,
+  const char *pToken, int nToken,
+  i64 iRowid, int iCol, int iOff
+){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  Fts5TokenDataIter *pT = pIter->pTokenDataIter;
+  Fts5Index *p = pIter->pIndex;
+  i64 iPos = (((i64)iCol)<<32) + iOff;
+
+  assert( p->pConfig->eDetail!=FTS5_DETAIL_FULL );
+  assert( pIter->pTokenDataIter || pIter->nSeg>0 );
+  if( pIter->nSeg>0 ){
+    /* This is a prefix term iterator. */
+    if( pT==0 ){
+      pT = (Fts5TokenDataIter*)sqlite3Fts5MallocZero(&p->rc, sizeof(*pT));
+      pIter->pTokenDataIter = pT;
+    }
+    if( pT ){
+      fts5TokendataIterAppendMap(p, pT, pT->terms.n, nToken, iRowid, iPos);
+      fts5BufferAppendBlob(&p->rc, &pT->terms, nToken, (const u8*)pToken);
+    }
+  }else{
+    int ii;
+    for(ii=0; ii<pT->nIter; ii++){
+      Fts5Buffer *pTerm = &pT->apIter[ii]->aSeg[0].term;
+      if( nToken==pTerm->n-1 && memcmp(pToken, pTerm->p+1, nToken)==0 ) break;
+    }
+    if( ii<pT->nIter ){
+      fts5TokendataIterAppendMap(p, pT, ii, 0, iRowid, iPos);
+    }
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** Close an iterator opened by an earlier call to sqlite3Fts5IndexQuery().
+*/
+static void sqlite3Fts5IterClose(Fts5IndexIter *pIndexIter){
+  if( pIndexIter ){
+    Fts5Index *pIndex = ((Fts5Iter*)pIndexIter)->pIndex;
+    fts5IterClose(pIndexIter);
+    fts5IndexReturn(pIndex);
+  }
+}
+
+/*
+** Read and decode the "averages" record from the database.
+**
+** Parameter anSize must point to an array of size nCol, where nCol is
+** the number of user defined columns in the FTS table.
+*/
+static int sqlite3Fts5IndexGetAverages(Fts5Index *p, i64 *pnRow, i64 *anSize){
+  int nCol = p->pConfig->nCol;
+  Fts5Data *pData;
+
+  *pnRow = 0;
+  memset(anSize, 0, sizeof(i64) * nCol);
+  pData = fts5DataRead(p, FTS5_AVERAGES_ROWID);
+  if( p->rc==SQLITE_OK && pData->nn ){
+    int i = 0;
+    int iCol;
+    i += fts5GetVarint(&pData->p[i], (u64*)pnRow);
+    for(iCol=0; i<pData->nn && iCol<nCol; iCol++){
+      i += fts5GetVarint(&pData->p[i], (u64*)&anSize[iCol]);
+    }
+  }
+
+  fts5DataRelease(pData);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Replace the current "averages" record with the contents of the buffer
+** supplied as the second argument.
+*/
+static int sqlite3Fts5IndexSetAverages(Fts5Index *p, const u8 *pData, int nData){
+  assert( p->rc==SQLITE_OK );
+  fts5DataWrite(p, FTS5_AVERAGES_ROWID, pData, nData);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Return the total number of blocks this module has read from the %_data
+** table since it was created.
+*/
+static int sqlite3Fts5IndexReads(Fts5Index *p){
+  return p->nRead;
+}
+
+/*
+** Set the 32-bit cookie value stored at the start of all structure
+** records to the value passed as the second argument.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int sqlite3Fts5IndexSetCookie(Fts5Index *p, int iNew){
+  int rc;                              /* Return code */
+  Fts5Config *pConfig = p->pConfig;    /* Configuration object */
+  u8 aCookie[4];                       /* Binary representation of iNew */
+  sqlite3_blob *pBlob = 0;
+
+  assert( p->rc==SQLITE_OK );
+  sqlite3Fts5Put32(aCookie, iNew);
+
+  rc = sqlite3_blob_open(pConfig->db, pConfig->zDb, p->zDataTbl,
+      "block", FTS5_STRUCTURE_ROWID, 1, &pBlob
+  );
+  if( rc==SQLITE_OK ){
+    sqlite3_blob_write(pBlob, aCookie, 4, 0);
+    rc = sqlite3_blob_close(pBlob);
+  }
+
+  return rc;
+}
+
+static int sqlite3Fts5IndexLoadConfig(Fts5Index *p){
+  Fts5Structure *pStruct;
+  pStruct = fts5StructureRead(p);
+  fts5StructureRelease(pStruct);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Retrieve the origin value that will be used for the segment currently
+** being accumulated in the in-memory hash table when it is flushed to
+** disk. If successful, SQLITE_OK is returned and (*piOrigin) set to
+** the queried value. Or, if an error occurs, an error code is returned
+** and the final value of (*piOrigin) is undefined.
+*/
+static int sqlite3Fts5IndexGetOrigin(Fts5Index *p, i64 *piOrigin){
+  Fts5Structure *pStruct;
+  pStruct = fts5StructureRead(p);
+  if( pStruct ){
+    *piOrigin = pStruct->nOriginCntr;
+    fts5StructureRelease(pStruct);
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** Buffer pPg contains a page of a tombstone hash table - one of nPg pages
+** associated with the same segment. This function adds rowid iRowid to
+** the hash table. The caller is required to guarantee that there is at
+** least one free slot on the page.
+**
+** If parameter bForce is false and the hash table is deemed to be full
+** (more than half of the slots are occupied), then non-zero is returned
+** and iRowid not inserted. Or, if bForce is true or if the hash table page
+** is not full, iRowid is inserted and zero returned.
+*/
+static int fts5IndexTombstoneAddToPage(
+  Fts5Data *pPg,
+  int bForce,
+  int nPg,
+  u64 iRowid
+){
+  const int szKey = TOMBSTONE_KEYSIZE(pPg);
+  const int nSlot = TOMBSTONE_NSLOT(pPg);
+  const int nElem = fts5GetU32(&pPg->p[4]);
+  int iSlot = (iRowid / nPg) % nSlot;
+  int nCollide = nSlot;
+
+  if( szKey==4 && iRowid>0xFFFFFFFF ) return 2;
+  if( iRowid==0 ){
+    pPg->p[1] = 0x01;
+    return 0;
+  }
+
+  if( bForce==0 && nElem>=(nSlot/2) ){
+    return 1;
+  }
+
+  fts5PutU32(&pPg->p[4], nElem+1);
+  if( szKey==4 ){
+    u32 *aSlot = (u32*)&pPg->p[8];
+    while( aSlot[iSlot] ){
+      iSlot = (iSlot + 1) % nSlot;
+      if( nCollide--==0 ) return 0;
+    }
+    fts5PutU32((u8*)&aSlot[iSlot], (u32)iRowid);
+  }else{
+    u64 *aSlot = (u64*)&pPg->p[8];
+    while( aSlot[iSlot] ){
+      iSlot = (iSlot + 1) % nSlot;
+      if( nCollide--==0 ) return 0;
+    }
+    fts5PutU64((u8*)&aSlot[iSlot], iRowid);
+  }
+
+  return 0;
+}
+
+/*
+** This function attempts to build a new hash containing all the keys
+** currently in the tombstone hash table for segment pSeg. The new
+** hash will be stored in the nOut buffers passed in array apOut[].
+** All pages of the new hash use key-size szKey (4 or 8).
+**
+** Return 0 if the hash is successfully rebuilt into the nOut pages.
+** Or non-zero if it is not (because one page became overfull). In this
+** case the caller should retry with a larger nOut parameter.
+**
+** Parameter pData1 is page iPg1 of the hash table being rebuilt.
+*/
+static int fts5IndexTombstoneRehash(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,     /* Segment to rebuild hash of */
+  Fts5Data *pData1,               /* One page of current hash - or NULL */
+  int iPg1,                       /* Which page of the current hash is pData1 */
+  int szKey,                      /* 4 or 8, the keysize */
+  int nOut,                       /* Number of output pages */
+  Fts5Data **apOut                /* Array of output hash pages */
+){
+  int ii;
+  int res = 0;
+
+  /* Initialize the headers of all the output pages */
+  for(ii=0; ii<nOut; ii++){
+    apOut[ii]->p[0] = szKey;
+    fts5PutU32(&apOut[ii]->p[4], 0);
+  }
+
+  /* Loop through the current pages of the hash table. */
+  for(ii=0; res==0 && ii<pSeg->nPgTombstone; ii++){
+    Fts5Data *pData = 0;          /* Page ii of the current hash table */
+    Fts5Data *pFree = 0;          /* Free this at the end of the loop */
+
+    if( iPg1==ii ){
+      pData = pData1;
+    }else{
+      pFree = pData = fts5DataRead(p, FTS5_TOMBSTONE_ROWID(pSeg->iSegid, ii));
+    }
+
+    if( pData ){
+      int szKeyIn = TOMBSTONE_KEYSIZE(pData);
+      int nSlotIn = (pData->nn - 8) / szKeyIn;
+      int iIn;
+      for(iIn=0; iIn<nSlotIn; iIn++){
+        u64 iVal = 0;
+
+        /* Read the value from slot iIn of the input page into iVal. */
+        if( szKeyIn==4 ){
+          u32 *aSlot = (u32*)&pData->p[8];
+          if( aSlot[iIn] ) iVal = fts5GetU32((u8*)&aSlot[iIn]);
+        }else{
+          u64 *aSlot = (u64*)&pData->p[8];
+          if( aSlot[iIn] ) iVal = fts5GetU64((u8*)&aSlot[iIn]);
+        }
+
+        /* If iVal is not 0 at this point, insert it into the new hash table */
+        if( iVal ){
+          Fts5Data *pPg = apOut[(iVal % nOut)];
+          res = fts5IndexTombstoneAddToPage(pPg, 0, nOut, iVal);
+          if( res ) break;
+        }
+      }
+
+      /* If this is page 0 of the old hash, copy the rowid-0-flag from the
+      ** old hash to the new.  */
+      if( ii==0 ){
+        apOut[0]->p[1] = pData->p[1];
+      }
+    }
+    fts5DataRelease(pFree);
+  }
+
+  return res;
+}
+
+/*
+** This is called to rebuild the hash table belonging to segment pSeg.
+** If parameter pData1 is not NULL, then one page of the existing hash table
+** has already been loaded - pData1, which is page iPg1. The key-size for
+** the new hash table is szKey (4 or 8).
+**
+** If successful, the new hash table is not written to disk. Instead,
+** output parameter (*pnOut) is set to the number of pages in the new
+** hash table, and (*papOut) to point to an array of buffers containing
+** the new page data.
+**
+** If an error occurs, an error code is left in the Fts5Index object and
+** both output parameters set to 0 before returning.
+*/
+static void fts5IndexTombstoneRebuild(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,     /* Segment to rebuild hash of */
+  Fts5Data *pData1,               /* One page of current hash - or NULL */
+  int iPg1,                       /* Which page of the current hash is pData1 */
+  int szKey,                      /* 4 or 8, the keysize */
+  int *pnOut,                     /* OUT: Number of output pages */
+  Fts5Data ***papOut              /* OUT: Output hash pages */
+){
+  const int MINSLOT = 32;
+  int nSlotPerPage = MAX(MINSLOT, (p->pConfig->pgsz - 8) / szKey);
+  int nSlot = 0;                  /* Number of slots in each output page */
+  int nOut = 0;
+
+  /* Figure out how many output pages (nOut) and how many slots per
+  ** page (nSlot).  There are three possibilities:
+  **
+  **   1. The hash table does not yet exist. In this case the new hash
+  **      table will consist of a single page with MINSLOT slots.
+  **
+  **   2. The hash table exists but is currently a single page. In this
+  **      case an attempt is made to grow the page to accommodate the new
+  **      entry. The page is allowed to grow up to nSlotPerPage (see above)
+  **      slots.
+  **
+  **   3. The hash table already consists of more than one page, or of
+  **      a single page already so large that it cannot be grown. In this
+  **      case the new hash consists of (nPg*2+1) pages of nSlotPerPage
+  **      slots each, where nPg is the current number of pages in the
+  **      hash table.
+  */
+  if( pSeg->nPgTombstone==0 ){
+    /* Case 1. */
+    nOut = 1;
+    nSlot = MINSLOT;
+  }else if( pSeg->nPgTombstone==1 ){
+    /* Case 2. */
+    int nElem = (int)fts5GetU32(&pData1->p[4]);
+    assert( pData1 && iPg1==0 );
+    nOut = 1;
+    nSlot = MAX(nElem*4, MINSLOT);
+    if( nSlot>nSlotPerPage ) nOut = 0;
+  }
+  if( nOut==0 ){
+    /* Case 3. */
+    nOut = (pSeg->nPgTombstone * 2 + 1);
+    nSlot = nSlotPerPage;
+  }
+
+  /* Allocate the required array and output pages */
+  while( 1 ){
+    int res = 0;
+    int ii = 0;
+    int szPage = 0;
+    Fts5Data **apOut = 0;
+
+    /* Allocate space for the new hash table */
+    assert( nSlot>=MINSLOT );
+    apOut = (Fts5Data**)sqlite3Fts5MallocZero(&p->rc, sizeof(Fts5Data*) * nOut);
+    szPage = 8 + nSlot*szKey;
+    for(ii=0; ii<nOut; ii++){
+      Fts5Data *pNew = (Fts5Data*)sqlite3Fts5MallocZero(&p->rc,
+          sizeof(Fts5Data)+szPage
+      );
+      if( pNew ){
+        pNew->nn = szPage;
+        pNew->p = (u8*)&pNew[1];
+        apOut[ii] = pNew;
+      }
+    }
+
+    /* Rebuild the hash table. */
+    if( p->rc==SQLITE_OK ){
+      res = fts5IndexTombstoneRehash(p, pSeg, pData1, iPg1, szKey, nOut, apOut);
+    }
+    if( res==0 ){
+      if( p->rc ){
+        fts5IndexFreeArray(apOut, nOut);
+        apOut = 0;
+        nOut = 0;
+      }
+      *pnOut = nOut;
+      *papOut = apOut;
+      break;
+    }
+
+    /* If control flows to here, it was not possible to rebuild the hash
+    ** table. Free all buffers and then try again with more pages. */
+    assert( p->rc==SQLITE_OK );
+    fts5IndexFreeArray(apOut, nOut);
+    nSlot = nSlotPerPage;
+    nOut = nOut*2 + 1;
+  }
+}
+
+
+/*
+** Add a tombstone for rowid iRowid to segment pSeg.
+*/
+static void fts5IndexTombstoneAdd(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,
+  u64 iRowid
+){
+  Fts5Data *pPg = 0;
+  int iPg = -1;
+  int szKey = 0;
+  int nHash = 0;
+  Fts5Data **apHash = 0;
+
+  p->nContentlessDelete++;
+
+  if( pSeg->nPgTombstone>0 ){
+    iPg = iRowid % pSeg->nPgTombstone;
+    pPg = fts5DataRead(p, FTS5_TOMBSTONE_ROWID(pSeg->iSegid,iPg));
+    if( pPg==0 ){
+      assert( p->rc!=SQLITE_OK );
+      return;
+    }
+
+    if( 0==fts5IndexTombstoneAddToPage(pPg, 0, pSeg->nPgTombstone, iRowid) ){
+      fts5DataWrite(p, FTS5_TOMBSTONE_ROWID(pSeg->iSegid,iPg), pPg->p, pPg->nn);
+      fts5DataRelease(pPg);
+      return;
+    }
+  }
+
+  /* Have to rebuild the hash table. First figure out the key-size (4 or 8). */
+  szKey = pPg ? TOMBSTONE_KEYSIZE(pPg) : 4;
+  if( iRowid>0xFFFFFFFF ) szKey = 8;
+
+  /* Rebuild the hash table */
+  fts5IndexTombstoneRebuild(p, pSeg, pPg, iPg, szKey, &nHash, &apHash);
+  assert( p->rc==SQLITE_OK || (nHash==0 && apHash==0) );
+
+  /* If all has succeeded, write the new rowid into one of the new hash
+  ** table pages, then write them all out to disk. */
+  if( nHash ){
+    int ii = 0;
+    fts5IndexTombstoneAddToPage(apHash[iRowid % nHash], 1, nHash, iRowid);
+    for(ii=0; ii<nHash; ii++){
+      i64 iTombstoneRowid = FTS5_TOMBSTONE_ROWID(pSeg->iSegid, ii);
+      fts5DataWrite(p, iTombstoneRowid, apHash[ii]->p, apHash[ii]->nn);
+    }
+    pSeg->nPgTombstone = nHash;
+    fts5StructureWrite(p, p->pStruct);
+  }
+
+  fts5DataRelease(pPg);
+  fts5IndexFreeArray(apHash, nHash);
+}
+
+/*
+** Add iRowid to the tombstone list of the segment or segments that contain
+** rows from origin iOrigin. Return SQLITE_OK if successful, or an SQLite
+** error code otherwise.
+*/
+static int sqlite3Fts5IndexContentlessDelete(Fts5Index *p, i64 iOrigin, i64 iRowid){
+  Fts5Structure *pStruct;
+  pStruct = fts5StructureRead(p);
+  if( pStruct ){
+    int bFound = 0;               /* True after pSeg->nEntryTombstone incr. */
+    int iLvl;
+    for(iLvl=pStruct->nLevel-1; iLvl>=0; iLvl--){
+      int iSeg;
+      for(iSeg=pStruct->aLevel[iLvl].nSeg-1; iSeg>=0; iSeg--){
+        Fts5StructureSegment *pSeg = &pStruct->aLevel[iLvl].aSeg[iSeg];
+        if( pSeg->iOrigin1<=(u64)iOrigin && pSeg->iOrigin2>=(u64)iOrigin ){
+          if( bFound==0 ){
+            pSeg->nEntryTombstone++;
+            bFound = 1;
+          }
+          fts5IndexTombstoneAdd(p, pSeg, iRowid);
+        }
+      }
+    }
+    fts5StructureRelease(pStruct);
+  }
+  return fts5IndexReturn(p);
+}
+
+/*************************************************************************
+**************************************************************************
+** Below this point is the implementation of the integrity-check
+** functionality.
+*/
+
+/*
+** Return a simple checksum value based on the arguments.
+*/
+static u64 sqlite3Fts5IndexEntryCksum(
+  i64 iRowid,
+  int iCol,
+  int iPos,
+  int iIdx,
+  const char *pTerm,
+  int nTerm
+){
+  int i;
+  u64 ret = iRowid;
+  ret += (ret<<3) + iCol;
+  ret += (ret<<3) + iPos;
+  if( iIdx>=0 ) ret += (ret<<3) + (FTS5_MAIN_PREFIX + iIdx);
+  for(i=0; i<nTerm; i++) ret += (ret<<3) + pTerm[i];
+  return ret;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** This function is purely an internal test. It does not contribute to
+** FTS functionality, or even the integrity-check, in any way.
+**
+** Instead, it tests that the same set of pgno/rowid combinations are
+** visited regardless of whether the doclist-index identified by parameters
+** iSegid/iLeaf is iterated in forwards or reverse order.
+*/
+static void fts5TestDlidxReverse(
+  Fts5Index *p,
+  int iSegid,                     /* Segment id to load from */
+  int iLeaf                       /* Load doclist-index for this leaf */
+){
+  Fts5DlidxIter *pDlidx = 0;
+  u64 cksum1 = 13;
+  u64 cksum2 = 13;
+
+  for(pDlidx=fts5DlidxIterInit(p, 0, iSegid, iLeaf);
+      fts5DlidxIterEof(p, pDlidx)==0;
+      fts5DlidxIterNext(p, pDlidx)
+  ){
+    i64 iRowid = fts5DlidxIterRowid(pDlidx);
+    int pgno = fts5DlidxIterPgno(pDlidx);
+    assert( pgno>iLeaf );
+    cksum1 += iRowid + ((i64)pgno<<32);
+  }
+  fts5DlidxIterFree(pDlidx);
+  pDlidx = 0;
+
+  for(pDlidx=fts5DlidxIterInit(p, 1, iSegid, iLeaf);
+      fts5DlidxIterEof(p, pDlidx)==0;
+      fts5DlidxIterPrev(p, pDlidx)
+  ){
+    i64 iRowid = fts5DlidxIterRowid(pDlidx);
+    int pgno = fts5DlidxIterPgno(pDlidx);
+    assert( fts5DlidxIterPgno(pDlidx)>iLeaf );
+    cksum2 += iRowid + ((i64)pgno<<32);
+  }
+  fts5DlidxIterFree(pDlidx);
+  pDlidx = 0;
+
+  if( p->rc==SQLITE_OK && cksum1!=cksum2 ) p->rc = FTS5_CORRUPT;
+}
+
+static int fts5QueryCksum(
+  Fts5Index *p,                   /* Fts5 index object */
+  int iIdx,
+  const char *z,                  /* Index key to query for */
+  int n,                          /* Size of index key in bytes */
+  int flags,                      /* Flags for Fts5IndexQuery */
+  u64 *pCksum                     /* IN/OUT: Checksum value */
+){
+  int eDetail = p->pConfig->eDetail;
+  u64 cksum = *pCksum;
+  Fts5IndexIter *pIter = 0;
+  int rc = sqlite3Fts5IndexQuery(
+      p, z, n, (flags | FTS5INDEX_QUERY_NOTOKENDATA), 0, &pIter
+  );
+
+  while( rc==SQLITE_OK && ALWAYS(pIter!=0) && 0==sqlite3Fts5IterEof(pIter) ){
+    i64 rowid = pIter->iRowid;
+
+    if( eDetail==FTS5_DETAIL_NONE ){
+      cksum ^= sqlite3Fts5IndexEntryCksum(rowid, 0, 0, iIdx, z, n);
+    }else{
+      Fts5PoslistReader sReader;
+      for(sqlite3Fts5PoslistReaderInit(pIter->pData, pIter->nData, &sReader);
+          sReader.bEof==0;
+          sqlite3Fts5PoslistReaderNext(&sReader)
+      ){
+        int iCol = FTS5_POS2COLUMN(sReader.iPos);
+        int iOff = FTS5_POS2OFFSET(sReader.iPos);
+        cksum ^= sqlite3Fts5IndexEntryCksum(rowid, iCol, iOff, iIdx, z, n);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5IterNext(pIter);
+    }
+  }
+  fts5IterClose(pIter);
+
+  *pCksum = cksum;
+  return rc;
+}
+
+/*
+** Check if buffer z[], size n bytes, contains as series of valid utf-8
+** encoded codepoints. If so, return 0. Otherwise, if the buffer does not
+** contain valid utf-8, return non-zero.
+*/
+static int fts5TestUtf8(const char *z, int n){
+  int i = 0;
+  assert_nc( n>0 );
+  while( i<n ){
+    if( (z[i] & 0x80)==0x00 ){
+      i++;
+    }else
+    if( (z[i] & 0xE0)==0xC0 ){
+      if( i+1>=n || (z[i+1] & 0xC0)!=0x80 ) return 1;
+      i += 2;
+    }else
+    if( (z[i] & 0xF0)==0xE0 ){
+      if( i+2>=n || (z[i+1] & 0xC0)!=0x80 || (z[i+2] & 0xC0)!=0x80 ) return 1;
+      i += 3;
+    }else
+    if( (z[i] & 0xF8)==0xF0 ){
+      if( i+3>=n || (z[i+1] & 0xC0)!=0x80 || (z[i+2] & 0xC0)!=0x80 ) return 1;
+      if( (z[i+2] & 0xC0)!=0x80 ) return 1;
+      i += 3;
+    }else{
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
+/*
+** This function is also purely an internal test. It does not contribute to
+** FTS functionality, or even the integrity-check, in any way.
+*/
+static void fts5TestTerm(
+  Fts5Index *p,
+  Fts5Buffer *pPrev,              /* Previous term */
+  const char *z, int n,           /* Possibly new term to test */
+  u64 expected,
+  u64 *pCksum
+){
+  int rc = p->rc;
+  if( pPrev->n==0 ){
+    fts5BufferSet(&rc, pPrev, n, (const u8*)z);
+  }else
+  if( rc==SQLITE_OK && (pPrev->n!=n || memcmp(pPrev->p, z, n)) ){
+    u64 cksum3 = *pCksum;
+    const char *zTerm = (const char*)&pPrev->p[1];  /* term sans prefix-byte */
+    int nTerm = pPrev->n-1;            /* Size of zTerm in bytes */
+    int iIdx = (pPrev->p[0] - FTS5_MAIN_PREFIX);
+    int flags = (iIdx==0 ? 0 : FTS5INDEX_QUERY_PREFIX);
+    u64 ck1 = 0;
+    u64 ck2 = 0;
+
+    /* Check that the results returned for ASC and DESC queries are
+    ** the same. If not, call this corruption.  */
+    rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, flags, &ck1);
+    if( rc==SQLITE_OK ){
+      int f = flags|FTS5INDEX_QUERY_DESC;
+      rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, f, &ck2);
+    }
+    if( rc==SQLITE_OK && ck1!=ck2 ) rc = FTS5_CORRUPT;
+
+    /* If this is a prefix query, check that the results returned if the
+    ** the index is disabled are the same. In both ASC and DESC order.
+    **
+    ** This check may only be performed if the hash table is empty. This
+    ** is because the hash table only supports a single scan query at
+    ** a time, and the multi-iter loop from which this function is called
+    ** is already performing such a scan.
+    **
+    ** Also only do this if buffer zTerm contains nTerm bytes of valid
+    ** utf-8. Otherwise, the last part of the buffer contents might contain
+    ** a non-utf-8 sequence that happens to be a prefix of a valid utf-8
+    ** character stored in the main fts index, which will cause the
+    ** test to fail.  */
+    if( p->nPendingData==0 && 0==fts5TestUtf8(zTerm, nTerm) ){
+      if( iIdx>0 && rc==SQLITE_OK ){
+        int f = flags|FTS5INDEX_QUERY_TEST_NOIDX;
+        ck2 = 0;
+        rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, f, &ck2);
+        if( rc==SQLITE_OK && ck1!=ck2 ) rc = FTS5_CORRUPT;
+      }
+      if( iIdx>0 && rc==SQLITE_OK ){
+        int f = flags|FTS5INDEX_QUERY_TEST_NOIDX|FTS5INDEX_QUERY_DESC;
+        ck2 = 0;
+        rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, f, &ck2);
+        if( rc==SQLITE_OK && ck1!=ck2 ) rc = FTS5_CORRUPT;
+      }
+    }
+
+    cksum3 ^= ck1;
+    fts5BufferSet(&rc, pPrev, n, (const u8*)z);
+
+    if( rc==SQLITE_OK && cksum3!=expected ){
+      rc = FTS5_CORRUPT;
+    }
+    *pCksum = cksum3;
+  }
+  p->rc = rc;
+}
+
+#else
+# define fts5TestDlidxReverse(x,y,z)
+# define fts5TestTerm(u,v,w,x,y,z)
+#endif
+
+/*
+** Check that:
+**
+**   1) All leaves of pSeg between iFirst and iLast (inclusive) exist and
+**      contain zero terms.
+**   2) All leaves of pSeg between iNoRowid and iLast (inclusive) exist and
+**      contain zero rowids.
+*/
+static void fts5IndexIntegrityCheckEmpty(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,     /* Segment to check internal consistency */
+  int iFirst,
+  int iNoRowid,
+  int iLast
+){
+  int i;
+
+  /* Now check that the iter.nEmpty leaves following the current leaf
+  ** (a) exist and (b) contain no terms. */
+  for(i=iFirst; p->rc==SQLITE_OK && i<=iLast; i++){
+    Fts5Data *pLeaf = fts5DataRead(p, FTS5_SEGMENT_ROWID(pSeg->iSegid, i));
+    if( pLeaf ){
+      if( !fts5LeafIsTermless(pLeaf) ) p->rc = FTS5_CORRUPT;
+      if( i>=iNoRowid && 0!=fts5LeafFirstRowidOff(pLeaf) ) p->rc = FTS5_CORRUPT;
+    }
+    fts5DataRelease(pLeaf);
+  }
+}
+
+static void fts5IntegrityCheckPgidx(Fts5Index *p, Fts5Data *pLeaf){
+  i64 iTermOff = 0;
+  int ii;
+
+  Fts5Buffer buf1 = {0,0,0};
+  Fts5Buffer buf2 = {0,0,0};
+
+  ii = pLeaf->szLeaf;
+  while( ii<pLeaf->nn && p->rc==SQLITE_OK ){
+    int res;
+    i64 iOff;
+    int nIncr;
+
+    ii += fts5GetVarint32(&pLeaf->p[ii], nIncr);
+    iTermOff += nIncr;
+    iOff = iTermOff;
+
+    if( iOff>=pLeaf->szLeaf ){
+      p->rc = FTS5_CORRUPT;
+    }else if( iTermOff==nIncr ){
+      int nByte;
+      iOff += fts5GetVarint32(&pLeaf->p[iOff], nByte);
+      if( (iOff+nByte)>pLeaf->szLeaf ){
+        p->rc = FTS5_CORRUPT;
+      }else{
+        fts5BufferSet(&p->rc, &buf1, nByte, &pLeaf->p[iOff]);
+      }
+    }else{
+      int nKeep, nByte;
+      iOff += fts5GetVarint32(&pLeaf->p[iOff], nKeep);
+      iOff += fts5GetVarint32(&pLeaf->p[iOff], nByte);
+      if( nKeep>buf1.n || (iOff+nByte)>pLeaf->szLeaf ){
+        p->rc = FTS5_CORRUPT;
+      }else{
+        buf1.n = nKeep;
+        fts5BufferAppendBlob(&p->rc, &buf1, nByte, &pLeaf->p[iOff]);
+      }
+
+      if( p->rc==SQLITE_OK ){
+        res = fts5BufferCompare(&buf1, &buf2);
+        if( res<=0 ) p->rc = FTS5_CORRUPT;
+      }
+    }
+    fts5BufferSet(&p->rc, &buf2, buf1.n, buf1.p);
+  }
+
+  fts5BufferFree(&buf1);
+  fts5BufferFree(&buf2);
+}
+
+static void fts5IndexIntegrityCheckSegment(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5StructureSegment *pSeg      /* Segment to check internal consistency */
+){
+  Fts5Config *pConfig = p->pConfig;
+  int bSecureDelete = (pConfig->iVersion==FTS5_CURRENT_VERSION_SECUREDELETE);
+  sqlite3_stmt *pStmt = 0;
+  int rc2;
+  int iIdxPrevLeaf = pSeg->pgnoFirst-1;
+  int iDlidxPrevLeaf = pSeg->pgnoLast;
+
+  if( pSeg->pgnoFirst==0 ) return;
+
+  fts5IndexPrepareStmt(p, &pStmt, sqlite3_mprintf(
+      "SELECT segid, term, (pgno>>1), (pgno&1) FROM %Q.'%q_idx' WHERE segid=%d "
+      "ORDER BY 1, 2",
+      pConfig->zDb, pConfig->zName, pSeg->iSegid
+  ));
+
+  /* Iterate through the b-tree hierarchy.  */
+  while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+    i64 iRow;                     /* Rowid for this leaf */
+    Fts5Data *pLeaf;              /* Data for this leaf */
+
+    const char *zIdxTerm = (const char*)sqlite3_column_blob(pStmt, 1);
+    int nIdxTerm = sqlite3_column_bytes(pStmt, 1);
+    int iIdxLeaf = sqlite3_column_int(pStmt, 2);
+    int bIdxDlidx = sqlite3_column_int(pStmt, 3);
+
+    /* If the leaf in question has already been trimmed from the segment,
+    ** ignore this b-tree entry. Otherwise, load it into memory. */
+    if( iIdxLeaf<pSeg->pgnoFirst ) continue;
+    iRow = FTS5_SEGMENT_ROWID(pSeg->iSegid, iIdxLeaf);
+    pLeaf = fts5LeafRead(p, iRow);
+    if( pLeaf==0 ) break;
+
+    /* Check that the leaf contains at least one term, and that it is equal
+    ** to or larger than the split-key in zIdxTerm.  Also check that if there
+    ** is also a rowid pointer within the leaf page header, it points to a
+    ** location before the term.  */
+    if( pLeaf->nn<=pLeaf->szLeaf ){
+
+      if( nIdxTerm==0
+       && pConfig->iVersion==FTS5_CURRENT_VERSION_SECUREDELETE
+       && pLeaf->nn==pLeaf->szLeaf
+       && pLeaf->nn==4
+      ){
+        /* special case - the very first page in a segment keeps its %_idx
+        ** entry even if all the terms are removed from it by secure-delete
+        ** operations. */
+      }else{
+        p->rc = FTS5_CORRUPT;
+      }
+
+    }else{
+      int iOff;                   /* Offset of first term on leaf */
+      int iRowidOff;              /* Offset of first rowid on leaf */
+      int nTerm;                  /* Size of term on leaf in bytes */
+      int res;                    /* Comparison of term and split-key */
+
+      iOff = fts5LeafFirstTermOff(pLeaf);
+      iRowidOff = fts5LeafFirstRowidOff(pLeaf);
+      if( iRowidOff>=iOff || iOff>=pLeaf->szLeaf ){
+        p->rc = FTS5_CORRUPT;
+      }else{
+        iOff += fts5GetVarint32(&pLeaf->p[iOff], nTerm);
+        res = fts5Memcmp(&pLeaf->p[iOff], zIdxTerm, MIN(nTerm, nIdxTerm));
+        if( res==0 ) res = nTerm - nIdxTerm;
+        if( res<0 ) p->rc = FTS5_CORRUPT;
+      }
+
+      fts5IntegrityCheckPgidx(p, pLeaf);
+    }
+    fts5DataRelease(pLeaf);
+    if( p->rc ) break;
+
+    /* Now check that the iter.nEmpty leaves following the current leaf
+    ** (a) exist and (b) contain no terms. */
+    fts5IndexIntegrityCheckEmpty(
+        p, pSeg, iIdxPrevLeaf+1, iDlidxPrevLeaf+1, iIdxLeaf-1
+    );
+    if( p->rc ) break;
+
+    /* If there is a doclist-index, check that it looks right. */
+    if( bIdxDlidx ){
+      Fts5DlidxIter *pDlidx = 0;  /* For iterating through doclist index */
+      int iPrevLeaf = iIdxLeaf;
+      int iSegid = pSeg->iSegid;
+      int iPg = 0;
+      i64 iKey;
+
+      for(pDlidx=fts5DlidxIterInit(p, 0, iSegid, iIdxLeaf);
+          fts5DlidxIterEof(p, pDlidx)==0;
+          fts5DlidxIterNext(p, pDlidx)
+      ){
+
+        /* Check any rowid-less pages that occur before the current leaf. */
+        for(iPg=iPrevLeaf+1; iPg<fts5DlidxIterPgno(pDlidx); iPg++){
+          iKey = FTS5_SEGMENT_ROWID(iSegid, iPg);
+          pLeaf = fts5DataRead(p, iKey);
+          if( pLeaf ){
+            if( fts5LeafFirstRowidOff(pLeaf)!=0 ) p->rc = FTS5_CORRUPT;
+            fts5DataRelease(pLeaf);
+          }
+        }
+        iPrevLeaf = fts5DlidxIterPgno(pDlidx);
+
+        /* Check that the leaf page indicated by the iterator really does
+        ** contain the rowid suggested by the same. */
+        iKey = FTS5_SEGMENT_ROWID(iSegid, iPrevLeaf);
+        pLeaf = fts5DataRead(p, iKey);
+        if( pLeaf ){
+          i64 iRowid;
+          int iRowidOff = fts5LeafFirstRowidOff(pLeaf);
+          ASSERT_SZLEAF_OK(pLeaf);
+          if( iRowidOff>=pLeaf->szLeaf ){
+            p->rc = FTS5_CORRUPT;
+          }else if( bSecureDelete==0 || iRowidOff>0 ){
+            i64 iDlRowid = fts5DlidxIterRowid(pDlidx);
+            fts5GetVarint(&pLeaf->p[iRowidOff], (u64*)&iRowid);
+            if( iRowid<iDlRowid || (bSecureDelete==0 && iRowid!=iDlRowid) ){
+              p->rc = FTS5_CORRUPT;
+            }
+          }
+          fts5DataRelease(pLeaf);
+        }
+      }
+
+      iDlidxPrevLeaf = iPg;
+      fts5DlidxIterFree(pDlidx);
+      fts5TestDlidxReverse(p, iSegid, iIdxLeaf);
+    }else{
+      iDlidxPrevLeaf = pSeg->pgnoLast;
+      /* TODO: Check there is no doclist index */
+    }
+
+    iIdxPrevLeaf = iIdxLeaf;
+  }
+
+  rc2 = sqlite3_finalize(pStmt);
+  if( p->rc==SQLITE_OK ) p->rc = rc2;
+
+  /* Page iter.iLeaf must now be the rightmost leaf-page in the segment */
+#if 0
+  if( p->rc==SQLITE_OK && iter.iLeaf!=pSeg->pgnoLast ){
+    p->rc = FTS5_CORRUPT;
+  }
+#endif
+}
+
+
+/*
+** Run internal checks to ensure that the FTS index (a) is internally
+** consistent and (b) contains entries for which the XOR of the checksums
+** as calculated by sqlite3Fts5IndexEntryCksum() is cksum.
+**
+** Return SQLITE_CORRUPT if any of the internal checks fail, or if the
+** checksum does not match. Return SQLITE_OK if all checks pass without
+** error, or some other SQLite error code if another error (e.g. OOM)
+** occurs.
+*/
+static int sqlite3Fts5IndexIntegrityCheck(Fts5Index *p, u64 cksum, int bUseCksum){
+  int eDetail = p->pConfig->eDetail;
+  u64 cksum2 = 0;                 /* Checksum based on contents of indexes */
+  Fts5Buffer poslist = {0,0,0};   /* Buffer used to hold a poslist */
+  Fts5Iter *pIter;                /* Used to iterate through entire index */
+  Fts5Structure *pStruct;         /* Index structure */
+  int iLvl, iSeg;
+
+#ifdef SQLITE_DEBUG
+  /* Used by extra internal tests only run if NDEBUG is not defined */
+  u64 cksum3 = 0;                 /* Checksum based on contents of indexes */
+  Fts5Buffer term = {0,0,0};      /* Buffer used to hold most recent term */
+#endif
+  const int flags = FTS5INDEX_QUERY_NOOUTPUT;
+
+  /* Load the FTS index structure */
+  pStruct = fts5StructureRead(p);
+  if( pStruct==0 ){
+    assert( p->rc!=SQLITE_OK );
+    return fts5IndexReturn(p);
+  }
+
+  /* Check that the internal nodes of each segment match the leaves */
+  for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+    for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
+      Fts5StructureSegment *pSeg = &pStruct->aLevel[iLvl].aSeg[iSeg];
+      fts5IndexIntegrityCheckSegment(p, pSeg);
+    }
+  }
+
+  /* The cksum argument passed to this function is a checksum calculated
+  ** based on all expected entries in the FTS index (including prefix index
+  ** entries). This block checks that a checksum calculated based on the
+  ** actual contents of FTS index is identical.
+  **
+  ** Two versions of the same checksum are calculated. The first (stack
+  ** variable cksum2) based on entries extracted from the full-text index
+  ** while doing a linear scan of each individual index in turn.
+  **
+  ** As each term visited by the linear scans, a separate query for the
+  ** same term is performed. cksum3 is calculated based on the entries
+  ** extracted by these queries.
+  */
+  for(fts5MultiIterNew(p, pStruct, flags, 0, 0, 0, -1, 0, &pIter);
+      fts5MultiIterEof(p, pIter)==0;
+      fts5MultiIterNext(p, pIter, 0, 0)
+  ){
+    int n;                      /* Size of term in bytes */
+    i64 iPos = 0;               /* Position read from poslist */
+    int iOff = 0;               /* Offset within poslist */
+    i64 iRowid = fts5MultiIterRowid(pIter);
+    char *z = (char*)fts5MultiIterTerm(pIter, &n);
+
+    /* If this is a new term, query for it. Update cksum3 with the results. */
+    fts5TestTerm(p, &term, z, n, cksum2, &cksum3);
+    if( p->rc ) break;
+
+    if( eDetail==FTS5_DETAIL_NONE ){
+      if( 0==fts5MultiIterIsEmpty(p, pIter) ){
+        cksum2 ^= sqlite3Fts5IndexEntryCksum(iRowid, 0, 0, -1, z, n);
+      }
+    }else{
+      poslist.n = 0;
+      fts5SegiterPoslist(p, &pIter->aSeg[pIter->aFirst[1].iFirst], 0, &poslist);
+      fts5BufferAppendBlob(&p->rc, &poslist, 4, (const u8*)"\0\0\0\0");
+      while( 0==sqlite3Fts5PoslistNext64(poslist.p, poslist.n, &iOff, &iPos) ){
+        int iCol = FTS5_POS2COLUMN(iPos);
+        int iTokOff = FTS5_POS2OFFSET(iPos);
+        cksum2 ^= sqlite3Fts5IndexEntryCksum(iRowid, iCol, iTokOff, -1, z, n);
+      }
+    }
+  }
+  fts5TestTerm(p, &term, 0, 0, cksum2, &cksum3);
+
+  fts5MultiIterFree(pIter);
+  if( p->rc==SQLITE_OK && bUseCksum && cksum!=cksum2 ) p->rc = FTS5_CORRUPT;
+
+  fts5StructureRelease(pStruct);
+#ifdef SQLITE_DEBUG
+  fts5BufferFree(&term);
+#endif
+  fts5BufferFree(&poslist);
+  return fts5IndexReturn(p);
+}
+
+/*************************************************************************
+**************************************************************************
+** Below this point is the implementation of the fts5_decode() scalar
+** function only.
+*/
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** Decode a segment-data rowid from the %_data table. This function is
+** the opposite of macro FTS5_SEGMENT_ROWID().
+*/
+static void fts5DecodeRowid(
+  i64 iRowid,                     /* Rowid from %_data table */
+  int *pbTombstone,               /* OUT: Tombstone hash flag */
+  int *piSegid,                   /* OUT: Segment id */
+  int *pbDlidx,                   /* OUT: Dlidx flag */
+  int *piHeight,                  /* OUT: Height */
+  int *piPgno                     /* OUT: Page number */
+){
+  *piPgno = (int)(iRowid & (((i64)1 << FTS5_DATA_PAGE_B) - 1));
+  iRowid >>= FTS5_DATA_PAGE_B;
+
+  *piHeight = (int)(iRowid & (((i64)1 << FTS5_DATA_HEIGHT_B) - 1));
+  iRowid >>= FTS5_DATA_HEIGHT_B;
+
+  *pbDlidx = (int)(iRowid & 0x0001);
+  iRowid >>= FTS5_DATA_DLI_B;
+
+  *piSegid = (int)(iRowid & (((i64)1 << FTS5_DATA_ID_B) - 1));
+  iRowid >>= FTS5_DATA_ID_B;
+
+  *pbTombstone = (int)(iRowid & 0x0001);
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+static void fts5DebugRowid(int *pRc, Fts5Buffer *pBuf, i64 iKey){
+  int iSegid, iHeight, iPgno, bDlidx, bTomb;     /* Rowid compenents */
+  fts5DecodeRowid(iKey, &bTomb, &iSegid, &bDlidx, &iHeight, &iPgno);
+
+  if( iSegid==0 ){
+    if( iKey==FTS5_AVERAGES_ROWID ){
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "{averages} ");
+    }else{
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "{structure}");
+    }
+  }
+  else{
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "{%s%ssegid=%d h=%d pgno=%d}",
+        bDlidx ? "dlidx " : "",
+        bTomb ? "tombstone " : "",
+        iSegid, iHeight, iPgno
+    );
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+static void fts5DebugStructure(
+  int *pRc,                       /* IN/OUT: error code */
+  Fts5Buffer *pBuf,
+  Fts5Structure *p
+){
+  int iLvl, iSeg;                 /* Iterate through levels, segments */
+
+  for(iLvl=0; iLvl<p->nLevel; iLvl++){
+    Fts5StructureLevel *pLvl = &p->aLevel[iLvl];
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf,
+        " {lvl=%d nMerge=%d nSeg=%d", iLvl, pLvl->nMerge, pLvl->nSeg
+    );
+    for(iSeg=0; iSeg<pLvl->nSeg; iSeg++){
+      Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " {id=%d leaves=%d..%d",
+          pSeg->iSegid, pSeg->pgnoFirst, pSeg->pgnoLast
+      );
+      if( pSeg->iOrigin1>0 ){
+        sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " origin=%lld..%lld",
+            pSeg->iOrigin1, pSeg->iOrigin2
+        );
+      }
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "}");
+    }
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "}");
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** This is part of the fts5_decode() debugging aid.
+**
+** Arguments pBlob/nBlob contain a serialized Fts5Structure object. This
+** function appends a human-readable representation of the same object
+** to the buffer passed as the second argument.
+*/
+static void fts5DecodeStructure(
+  int *pRc,                       /* IN/OUT: error code */
+  Fts5Buffer *pBuf,
+  const u8 *pBlob, int nBlob
+){
+  int rc;                         /* Return code */
+  Fts5Structure *p = 0;           /* Decoded structure object */
+
+  rc = fts5StructureDecode(pBlob, nBlob, 0, &p);
+  if( rc!=SQLITE_OK ){
+    *pRc = rc;
+    return;
+  }
+
+  fts5DebugStructure(pRc, pBuf, p);
+  fts5StructureRelease(p);
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** This is part of the fts5_decode() debugging aid.
+**
+** Arguments pBlob/nBlob contain an "averages" record. This function
+** appends a human-readable representation of record to the buffer passed
+** as the second argument.
+*/
+static void fts5DecodeAverages(
+  int *pRc,                       /* IN/OUT: error code */
+  Fts5Buffer *pBuf,
+  const u8 *pBlob, int nBlob
+){
+  int i = 0;
+  const char *zSpace = "";
+
+  while( i<nBlob ){
+    u64 iVal;
+    i += sqlite3Fts5GetVarint(&pBlob[i], &iVal);
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "%s%d", zSpace, (int)iVal);
+    zSpace = " ";
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** Buffer (a/n) is assumed to contain a list of serialized varints. Read
+** each varint and append its string representation to buffer pBuf. Return
+** after either the input buffer is exhausted or a 0 value is read.
+**
+** The return value is the number of bytes read from the input buffer.
+*/
+static int fts5DecodePoslist(int *pRc, Fts5Buffer *pBuf, const u8 *a, int n){
+  int iOff = 0;
+  while( iOff<n ){
+    int iVal;
+    iOff += fts5GetVarint32(&a[iOff], iVal);
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " %d", iVal);
+  }
+  return iOff;
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** The start of buffer (a/n) contains the start of a doclist. The doclist
+** may or may not finish within the buffer. This function appends a text
+** representation of the part of the doclist that is present to buffer
+** pBuf.
+**
+** The return value is the number of bytes read from the input buffer.
+*/
+static int fts5DecodeDoclist(int *pRc, Fts5Buffer *pBuf, const u8 *a, int n){
+  i64 iDocid = 0;
+  int iOff = 0;
+
+  if( n>0 ){
+    iOff = sqlite3Fts5GetVarint(a, (u64*)&iDocid);
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " id=%lld", iDocid);
+  }
+  while( iOff<n ){
+    int nPos;
+    int bDel;
+    iOff += fts5GetPoslistSize(&a[iOff], &nPos, &bDel);
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " nPos=%d%s", nPos, bDel?"*":"");
+    iOff += fts5DecodePoslist(pRc, pBuf, &a[iOff], MIN(n-iOff, nPos));
+    if( iOff<n ){
+      i64 iDelta;
+      iOff += sqlite3Fts5GetVarint(&a[iOff], (u64*)&iDelta);
+      iDocid += iDelta;
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " id=%lld", iDocid);
+    }
+  }
+
+  return iOff;
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** This function is part of the fts5_decode() debugging function. It is
+** only ever used with detail=none tables.
+**
+** Buffer (pData/nData) contains a doclist in the format used by detail=none
+** tables. This function appends a human-readable version of that list to
+** buffer pBuf.
+**
+** If *pRc is other than SQLITE_OK when this function is called, it is a
+** no-op. If an OOM or other error occurs within this function, *pRc is
+** set to an SQLite error code before returning. The final state of buffer
+** pBuf is undefined in this case.
+*/
+static void fts5DecodeRowidList(
+  int *pRc,                       /* IN/OUT: Error code */
+  Fts5Buffer *pBuf,               /* Buffer to append text to */
+  const u8 *pData, int nData      /* Data to decode list-of-rowids from */
+){
+  int i = 0;
+  i64 iRowid = 0;
+
+  while( i<nData ){
+    const char *zApp = "";
+    u64 iVal;
+    i += sqlite3Fts5GetVarint(&pData[i], &iVal);
+    iRowid += iVal;
+
+    if( i<nData && pData[i]==0x00 ){
+      i++;
+      if( i<nData && pData[i]==0x00 ){
+        i++;
+        zApp = "+";
+      }else{
+        zApp = "*";
+      }
+    }
+
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " %lld%s", iRowid, zApp);
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+static void fts5BufferAppendTerm(int *pRc, Fts5Buffer *pBuf, Fts5Buffer *pTerm){
+  int ii;
+  fts5BufferGrow(pRc, pBuf, pTerm->n*2 + 1);
+  if( *pRc==SQLITE_OK ){
+    for(ii=0; ii<pTerm->n; ii++){
+      if( pTerm->p[ii]==0x00 ){
+        pBuf->p[pBuf->n++] = '\\';
+        pBuf->p[pBuf->n++] = '0';
+      }else{
+        pBuf->p[pBuf->n++] = pTerm->p[ii];
+      }
+    }
+    pBuf->p[pBuf->n] = 0x00;
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** The implementation of user-defined scalar function fts5_decode().
+*/
+static void fts5DecodeFunction(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args (always 2) */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  i64 iRowid;                     /* Rowid for record being decoded */
+  int iSegid,iHeight,iPgno,bDlidx;/* Rowid components */
+  int bTomb;
+  const u8 *aBlob; int n;         /* Record to decode */
+  u8 *a = 0;
+  Fts5Buffer s;                   /* Build up text to return here */
+  int rc = SQLITE_OK;             /* Return code */
+  sqlite3_int64 nSpace = 0;
+  int eDetailNone = (sqlite3_user_data(pCtx)!=0);
+
+  assert( nArg==2 );
+  UNUSED_PARAM(nArg);
+  memset(&s, 0, sizeof(Fts5Buffer));
+  iRowid = sqlite3_value_int64(apVal[0]);
+
+  /* Make a copy of the second argument (a blob) in aBlob[]. The aBlob[]
+  ** copy is followed by FTS5_DATA_ZERO_PADDING 0x00 bytes, which prevents
+  ** buffer overreads even if the record is corrupt.  */
+  n = sqlite3_value_bytes(apVal[1]);
+  aBlob = sqlite3_value_blob(apVal[1]);
+  nSpace = n + FTS5_DATA_ZERO_PADDING;
+  a = (u8*)sqlite3Fts5MallocZero(&rc, nSpace);
+  if( a==0 ) goto decode_out;
+  if( n>0 ) memcpy(a, aBlob, n);
+
+  fts5DecodeRowid(iRowid, &bTomb, &iSegid, &bDlidx, &iHeight, &iPgno);
+
+  fts5DebugRowid(&rc, &s, iRowid);
+  if( bDlidx ){
+    Fts5Data dlidx;
+    Fts5DlidxLvl lvl;
+
+    dlidx.p = a;
+    dlidx.nn = n;
+
+    memset(&lvl, 0, sizeof(Fts5DlidxLvl));
+    lvl.pData = &dlidx;
+    lvl.iLeafPgno = iPgno;
+
+    for(fts5DlidxLvlNext(&lvl); lvl.bEof==0; fts5DlidxLvlNext(&lvl)){
+      sqlite3Fts5BufferAppendPrintf(&rc, &s,
+          " %d(%lld)", lvl.iLeafPgno, lvl.iRowid
+      );
+    }
+  }else if( bTomb ){
+    u32 nElem  = fts5GetU32(&a[4]);
+    int szKey = (aBlob[0]==4 || aBlob[0]==8) ? aBlob[0] : 8;
+    int nSlot = (n - 8) / szKey;
+    int ii;
+    sqlite3Fts5BufferAppendPrintf(&rc, &s, " nElem=%d", (int)nElem);
+    if( aBlob[1] ){
+      sqlite3Fts5BufferAppendPrintf(&rc, &s, " 0");
+    }
+    for(ii=0; ii<nSlot; ii++){
+      u64 iVal = 0;
+      if( szKey==4 ){
+        u32 *aSlot = (u32*)&aBlob[8];
+        if( aSlot[ii] ) iVal = fts5GetU32((u8*)&aSlot[ii]);
+      }else{
+        u64 *aSlot = (u64*)&aBlob[8];
+        if( aSlot[ii] ) iVal = fts5GetU64((u8*)&aSlot[ii]);
+      }
+      if( iVal!=0 ){
+        sqlite3Fts5BufferAppendPrintf(&rc, &s, " %lld", (i64)iVal);
+      }
+    }
+  }else if( iSegid==0 ){
+    if( iRowid==FTS5_AVERAGES_ROWID ){
+      fts5DecodeAverages(&rc, &s, a, n);
+    }else{
+      fts5DecodeStructure(&rc, &s, a, n);
+    }
+  }else if( eDetailNone ){
+    Fts5Buffer term;              /* Current term read from page */
+    int szLeaf;
+    int iPgidxOff = szLeaf = fts5GetU16(&a[2]);
+    int iTermOff;
+    int nKeep = 0;
+    int iOff;
+
+    memset(&term, 0, sizeof(Fts5Buffer));
+
+    /* Decode any entries that occur before the first term. */
+    if( szLeaf<n ){
+      iPgidxOff += fts5GetVarint32(&a[iPgidxOff], iTermOff);
+    }else{
+      iTermOff = szLeaf;
+    }
+    fts5DecodeRowidList(&rc, &s, &a[4], iTermOff-4);
+
+    iOff = iTermOff;
+    while( iOff<szLeaf && rc==SQLITE_OK ){
+      int nAppend;
+
+      /* Read the term data for the next term*/
+      iOff += fts5GetVarint32(&a[iOff], nAppend);
+      term.n = nKeep;
+      fts5BufferAppendBlob(&rc, &term, nAppend, &a[iOff]);
+      sqlite3Fts5BufferAppendPrintf(&rc, &s, " term=");
+      fts5BufferAppendTerm(&rc, &s, &term);
+      iOff += nAppend;
+
+      /* Figure out where the doclist for this term ends */
+      if( iPgidxOff<n ){
+        int nIncr;
+        iPgidxOff += fts5GetVarint32(&a[iPgidxOff], nIncr);
+        iTermOff += nIncr;
+      }else{
+        iTermOff = szLeaf;
+      }
+      if( iTermOff>szLeaf ){
+        rc = FTS5_CORRUPT;
+      }else{
+        fts5DecodeRowidList(&rc, &s, &a[iOff], iTermOff-iOff);
+      }
+      iOff = iTermOff;
+      if( iOff<szLeaf ){
+        iOff += fts5GetVarint32(&a[iOff], nKeep);
+      }
+    }
+
+    fts5BufferFree(&term);
+  }else{
+    Fts5Buffer term;              /* Current term read from page */
+    int szLeaf;                   /* Offset of pgidx in a[] */
+    int iPgidxOff;
+    int iPgidxPrev = 0;           /* Previous value read from pgidx */
+    int iTermOff = 0;
+    int iRowidOff = 0;
+    int iOff;
+    int nDoclist;
+
+    memset(&term, 0, sizeof(Fts5Buffer));
+
+    if( n<4 ){
+      sqlite3Fts5BufferSet(&rc, &s, 7, (const u8*)"corrupt");
+      goto decode_out;
+    }else{
+      iRowidOff = fts5GetU16(&a[0]);
+      iPgidxOff = szLeaf = fts5GetU16(&a[2]);
+      if( iPgidxOff<n ){
+        fts5GetVarint32(&a[iPgidxOff], iTermOff);
+      }else if( iPgidxOff>n ){
+        rc = FTS5_CORRUPT;
+        goto decode_out;
+      }
+    }
+
+    /* Decode the position list tail at the start of the page */
+    if( iRowidOff!=0 ){
+      iOff = iRowidOff;
+    }else if( iTermOff!=0 ){
+      iOff = iTermOff;
+    }else{
+      iOff = szLeaf;
+    }
+    if( iOff>n ){
+      rc = FTS5_CORRUPT;
+      goto decode_out;
+    }
+    fts5DecodePoslist(&rc, &s, &a[4], iOff-4);
+
+    /* Decode any more doclist data that appears on the page before the
+    ** first term. */
+    nDoclist = (iTermOff ? iTermOff : szLeaf) - iOff;
+    if( nDoclist+iOff>n ){
+      rc = FTS5_CORRUPT;
+      goto decode_out;
+    }
+    fts5DecodeDoclist(&rc, &s, &a[iOff], nDoclist);
+
+    while( iPgidxOff<n && rc==SQLITE_OK ){
+      int bFirst = (iPgidxOff==szLeaf);     /* True for first term on page */
+      int nByte;                            /* Bytes of data */
+      int iEnd;
+
+      iPgidxOff += fts5GetVarint32(&a[iPgidxOff], nByte);
+      iPgidxPrev += nByte;
+      iOff = iPgidxPrev;
+
+      if( iPgidxOff<n ){
+        fts5GetVarint32(&a[iPgidxOff], nByte);
+        iEnd = iPgidxPrev + nByte;
+      }else{
+        iEnd = szLeaf;
+      }
+      if( iEnd>szLeaf ){
+        rc = FTS5_CORRUPT;
+        break;
+      }
+
+      if( bFirst==0 ){
+        iOff += fts5GetVarint32(&a[iOff], nByte);
+        if( nByte>term.n ){
+          rc = FTS5_CORRUPT;
+          break;
+        }
+        term.n = nByte;
+      }
+      iOff += fts5GetVarint32(&a[iOff], nByte);
+      if( iOff+nByte>n ){
+        rc = FTS5_CORRUPT;
+        break;
+      }
+      fts5BufferAppendBlob(&rc, &term, nByte, &a[iOff]);
+      iOff += nByte;
+
+      sqlite3Fts5BufferAppendPrintf(&rc, &s, " term=");
+      fts5BufferAppendTerm(&rc, &s, &term);
+      iOff += fts5DecodeDoclist(&rc, &s, &a[iOff], iEnd-iOff);
+    }
+
+    fts5BufferFree(&term);
+  }
+
+ decode_out:
+  sqlite3_free(a);
+  if( rc==SQLITE_OK ){
+    sqlite3_result_text(pCtx, (const char*)s.p, s.n, SQLITE_TRANSIENT);
+  }else{
+    sqlite3_result_error_code(pCtx, rc);
+  }
+  fts5BufferFree(&s);
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** The implementation of user-defined scalar function fts5_rowid().
+*/
+static void fts5RowidFunction(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args (always 2) */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  const char *zArg;
+  if( nArg==0 ){
+    sqlite3_result_error(pCtx, "should be: fts5_rowid(subject, ....)", -1);
+  }else{
+    zArg = (const char*)sqlite3_value_text(apVal[0]);
+    if( 0==sqlite3_stricmp(zArg, "segment") ){
+      i64 iRowid;
+      int segid, pgno;
+      if( nArg!=3 ){
+        sqlite3_result_error(pCtx,
+            "should be: fts5_rowid('segment', segid, pgno))", -1
+        );
+      }else{
+        segid = sqlite3_value_int(apVal[1]);
+        pgno = sqlite3_value_int(apVal[2]);
+        iRowid = FTS5_SEGMENT_ROWID(segid, pgno);
+        sqlite3_result_int64(pCtx, iRowid);
+      }
+    }else{
+      sqlite3_result_error(pCtx,
+        "first arg to fts5_rowid() must be 'segment'" , -1
+      );
+    }
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+
+typedef struct Fts5StructVtab Fts5StructVtab;
+struct Fts5StructVtab {
+  sqlite3_vtab base;
+};
+
+typedef struct Fts5StructVcsr Fts5StructVcsr;
+struct Fts5StructVcsr {
+  sqlite3_vtab_cursor base;
+  Fts5Structure *pStruct;
+  int iLevel;
+  int iSeg;
+  int iRowid;
+};
+
+/*
+** Create a new fts5_structure() table-valued function.
+*/
+static int fts5structConnectMethod(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  Fts5StructVtab *pNew = 0;
+  int rc = SQLITE_OK;
+
+  rc = sqlite3_declare_vtab(db,
+      "CREATE TABLE xyz("
+          "level, segment, merge, segid, leaf1, leaf2, loc1, loc2, "
+          "npgtombstone, nentrytombstone, nentry, struct HIDDEN);"
+  );
+  if( rc==SQLITE_OK ){
+    pNew = sqlite3Fts5MallocZero(&rc, sizeof(*pNew));
+  }
+
+  *ppVtab = (sqlite3_vtab*)pNew;
+  return rc;
+}
+
+/*
+** We must have a single struct=? constraint that will be passed through
+** into the xFilter method.  If there is no valid struct=? constraint,
+** then return an SQLITE_CONSTRAINT error.
+*/
+static int fts5structBestIndexMethod(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  int i;
+  int rc = SQLITE_CONSTRAINT;
+  struct sqlite3_index_constraint *p;
+  pIdxInfo->estimatedCost = (double)100;
+  pIdxInfo->estimatedRows = 100;
+  pIdxInfo->idxNum = 0;
+  for(i=0, p=pIdxInfo->aConstraint; i<pIdxInfo->nConstraint; i++, p++){
+    if( p->usable==0 ) continue;
+    if( p->op==SQLITE_INDEX_CONSTRAINT_EQ && p->iColumn==11 ){
+      rc = SQLITE_OK;
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
+      break;
+    }
+  }
+  return rc;
+}
+
+/*
+** This method is the destructor for bytecodevtab objects.
+*/
+static int fts5structDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts5StructVtab *p = (Fts5StructVtab*)pVtab;
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Constructor for a new bytecodevtab_cursor object.
+*/
+static int fts5structOpenMethod(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCsr){
+  int rc = SQLITE_OK;
+  Fts5StructVcsr *pNew = 0;
+
+  pNew = sqlite3Fts5MallocZero(&rc, sizeof(*pNew));
+  *ppCsr = (sqlite3_vtab_cursor*)pNew;
+
+  return SQLITE_OK;
+}
+
+/*
+** Destructor for a bytecodevtab_cursor.
+*/
+static int fts5structCloseMethod(sqlite3_vtab_cursor *cur){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  fts5StructureRelease(pCsr->pStruct);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+
+/*
+** Advance a bytecodevtab_cursor to its next row of output.
+*/
+static int fts5structNextMethod(sqlite3_vtab_cursor *cur){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  Fts5Structure *p = pCsr->pStruct;
+
+  assert( pCsr->pStruct );
+  pCsr->iSeg++;
+  pCsr->iRowid++;
+  while( pCsr->iLevel<p->nLevel && pCsr->iSeg>=p->aLevel[pCsr->iLevel].nSeg ){
+    pCsr->iLevel++;
+    pCsr->iSeg = 0;
+  }
+  if( pCsr->iLevel>=p->nLevel ){
+    fts5StructureRelease(pCsr->pStruct);
+    pCsr->pStruct = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the cursor has been moved off of the last
+** row of output.
+*/
+static int fts5structEofMethod(sqlite3_vtab_cursor *cur){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  return pCsr->pStruct==0;
+}
+
+static int fts5structRowidMethod(
+  sqlite3_vtab_cursor *cur,
+  sqlite_int64 *piRowid
+){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  *piRowid = pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Return values of columns for the row at which the bytecodevtab_cursor
+** is currently pointing.
+*/
+static int fts5structColumnMethod(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int i                       /* Which column to return */
+){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  Fts5Structure *p = pCsr->pStruct;
+  Fts5StructureSegment *pSeg = &p->aLevel[pCsr->iLevel].aSeg[pCsr->iSeg];
+
+  switch( i ){
+    case 0: /* level */
+      sqlite3_result_int(ctx, pCsr->iLevel);
+      break;
+    case 1: /* segment */
+      sqlite3_result_int(ctx, pCsr->iSeg);
+      break;
+    case 2: /* merge */
+      sqlite3_result_int(ctx, pCsr->iSeg < p->aLevel[pCsr->iLevel].nMerge);
+      break;
+    case 3: /* segid */
+      sqlite3_result_int(ctx, pSeg->iSegid);
+      break;
+    case 4: /* leaf1 */
+      sqlite3_result_int(ctx, pSeg->pgnoFirst);
+      break;
+    case 5: /* leaf2 */
+      sqlite3_result_int(ctx, pSeg->pgnoLast);
+      break;
+    case 6: /* origin1 */
+      sqlite3_result_int64(ctx, pSeg->iOrigin1);
+      break;
+    case 7: /* origin2 */
+      sqlite3_result_int64(ctx, pSeg->iOrigin2);
+      break;
+    case 8: /* npgtombstone */
+      sqlite3_result_int(ctx, pSeg->nPgTombstone);
+      break;
+    case 9: /* nentrytombstone */
+      sqlite3_result_int64(ctx, pSeg->nEntryTombstone);
+      break;
+    case 10: /* nentry */
+      sqlite3_result_int64(ctx, pSeg->nEntry);
+      break;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Initialize a cursor.
+**
+**    idxNum==0     means show all subprograms
+**    idxNum==1     means show only the main bytecode and omit subprograms.
+*/
+static int fts5structFilterMethod(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr *)pVtabCursor;
+  int rc = SQLITE_OK;
+
+  const u8 *aBlob = 0;
+  int nBlob = 0;
+
+  assert( argc==1 );
+  fts5StructureRelease(pCsr->pStruct);
+  pCsr->pStruct = 0;
+
+  nBlob = sqlite3_value_bytes(argv[0]);
+  aBlob = (const u8*)sqlite3_value_blob(argv[0]);
+  rc = fts5StructureDecode(aBlob, nBlob, 0, &pCsr->pStruct);
+  if( rc==SQLITE_OK ){
+    pCsr->iLevel = 0;
+    pCsr->iRowid = 0;
+    pCsr->iSeg = -1;
+    rc = fts5structNextMethod(pVtabCursor);
+  }
+
+  return rc;
+}
+
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+/*
+** This is called as part of registering the FTS5 module with database
+** connection db. It registers several user-defined scalar functions useful
+** with FTS5.
+**
+** If successful, SQLITE_OK is returned. If an error occurs, some other
+** SQLite error code is returned instead.
+*/
+static int sqlite3Fts5IndexInit(sqlite3 *db){
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+  int rc = sqlite3_create_function(
+      db, "fts5_decode", 2, SQLITE_UTF8, 0, fts5DecodeFunction, 0, 0
+  );
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(
+        db, "fts5_decode_none", 2,
+        SQLITE_UTF8, (void*)db, fts5DecodeFunction, 0, 0
+    );
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(
+        db, "fts5_rowid", -1, SQLITE_UTF8, 0, fts5RowidFunction, 0, 0
+    );
+  }
+
+  if( rc==SQLITE_OK ){
+    static const sqlite3_module fts5structure_module = {
+      0,                           /* iVersion      */
+      0,                           /* xCreate       */
+      fts5structConnectMethod,     /* xConnect      */
+      fts5structBestIndexMethod,   /* xBestIndex    */
+      fts5structDisconnectMethod,  /* xDisconnect   */
+      0,                           /* xDestroy      */
+      fts5structOpenMethod,        /* xOpen         */
+      fts5structCloseMethod,       /* xClose        */
+      fts5structFilterMethod,      /* xFilter       */
+      fts5structNextMethod,        /* xNext         */
+      fts5structEofMethod,         /* xEof          */
+      fts5structColumnMethod,      /* xColumn       */
+      fts5structRowidMethod,       /* xRowid        */
+      0,                           /* xUpdate       */
+      0,                           /* xBegin        */
+      0,                           /* xSync         */
+      0,                           /* xCommit       */
+      0,                           /* xRollback     */
+      0,                           /* xFindFunction */
+      0,                           /* xRename       */
+      0,                           /* xSavepoint    */
+      0,                           /* xRelease      */
+      0,                           /* xRollbackTo   */
+      0,                           /* xShadowName   */
+      0                            /* xIntegrity    */
+    };
+    rc = sqlite3_create_module(db, "fts5_structure", &fts5structure_module, 0);
+  }
+  return rc;
+#else
+  return SQLITE_OK;
+  UNUSED_PARAM(db);
+#endif
+}
+
+
+static int sqlite3Fts5IndexReset(Fts5Index *p){
+  assert( p->pStruct==0 || p->iStructVersion!=0 );
+  if( fts5IndexDataVersion(p)!=p->iStructVersion ){
+    fts5StructureInvalidate(p);
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** 2014 Jun 09
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is an SQLite module implementing full-text search.
+*/
+
+
+/* #include "fts5Int.h" */
+
+/*
+** This variable is set to false when running tests for which the on disk
+** structures should not be corrupt. Otherwise, true. If it is false, extra
+** assert() conditions in the fts5 code are activated - conditions that are
+** only true if it is guaranteed that the fts5 database is not corrupt.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_API int sqlite3_fts5_may_be_corrupt = 1;
+#endif
+
+
+typedef struct Fts5Auxdata Fts5Auxdata;
+typedef struct Fts5Auxiliary Fts5Auxiliary;
+typedef struct Fts5Cursor Fts5Cursor;
+typedef struct Fts5FullTable Fts5FullTable;
+typedef struct Fts5Sorter Fts5Sorter;
+typedef struct Fts5TokenizerModule Fts5TokenizerModule;
+
+/*
+** NOTES ON TRANSACTIONS:
+**
+** SQLite invokes the following virtual table methods as transactions are
+** opened and closed by the user:
+**
+**     xBegin():    Start of a new transaction.
+**     xSync():     Initial part of two-phase commit.
+**     xCommit():   Final part of two-phase commit.
+**     xRollback(): Rollback the transaction.
+**
+** Anything that is required as part of a commit that may fail is performed
+** in the xSync() callback. Current versions of SQLite ignore any errors
+** returned by xCommit().
+**
+** And as sub-transactions are opened/closed:
+**
+**     xSavepoint(int S):  Open savepoint S.
+**     xRelease(int S):    Commit and close savepoint S.
+**     xRollbackTo(int S): Rollback to start of savepoint S.
+**
+** During a write-transaction the fts5_index.c module may cache some data
+** in-memory. It is flushed to disk whenever xSync(), xRelease() or
+** xSavepoint() is called. And discarded whenever xRollback() or xRollbackTo()
+** is called.
+**
+** Additionally, if SQLITE_DEBUG is defined, an instance of the following
+** structure is used to record the current transaction state. This information
+** is not required, but it is used in the assert() statements executed by
+** function fts5CheckTransactionState() (see below).
+*/
+struct Fts5TransactionState {
+  int eState;                     /* 0==closed, 1==open, 2==synced */
+  int iSavepoint;                 /* Number of open savepoints (0 -> none) */
+};
+
+/*
+** A single object of this type is allocated when the FTS5 module is
+** registered with a database handle. It is used to store pointers to
+** all registered FTS5 extensions - tokenizers and auxiliary functions.
+*/
+struct Fts5Global {
+  fts5_api api;                   /* User visible part of object (see fts5.h) */
+  sqlite3 *db;                    /* Associated database connection */
+  i64 iNextId;                    /* Used to allocate unique cursor ids */
+  Fts5Auxiliary *pAux;            /* First in list of all aux. functions */
+  Fts5TokenizerModule *pTok;      /* First in list of all tokenizer modules */
+  Fts5TokenizerModule *pDfltTok;  /* Default tokenizer module */
+  Fts5Cursor *pCsr;               /* First in list of all open cursors */
+  u32 aLocaleHdr[4];
+};
+
+/*
+** Size of header on fts5_locale() values. And macro to access a buffer
+** containing a copy of the header from an Fts5Config pointer.
+*/
+#define FTS5_LOCALE_HDR_SIZE ((int)sizeof( ((Fts5Global*)0)->aLocaleHdr ))
+#define FTS5_LOCALE_HDR(pConfig) ((const u8*)(pConfig->pGlobal->aLocaleHdr))
+
+#define FTS5_INSTTOKEN_SUBTYPE 73
+
+/*
+** Each auxiliary function registered with the FTS5 module is represented
+** by an object of the following type. All such objects are stored as part
+** of the Fts5Global.pAux list.
+*/
+struct Fts5Auxiliary {
+  Fts5Global *pGlobal;            /* Global context for this function */
+  char *zFunc;                    /* Function name (nul-terminated) */
+  void *pUserData;                /* User-data pointer */
+  fts5_extension_function xFunc;  /* Callback function */
+  void (*xDestroy)(void*);        /* Destructor function */
+  Fts5Auxiliary *pNext;           /* Next registered auxiliary function */
+};
+
+/*
+** Each tokenizer module registered with the FTS5 module is represented
+** by an object of the following type. All such objects are stored as part
+** of the Fts5Global.pTok list.
+**
+** bV2Native:
+**  True if the tokenizer was registered using xCreateTokenizer_v2(), false
+**  for xCreateTokenizer(). If this variable is true, then x2 is populated
+**  with the routines as supplied by the caller and x1 contains synthesized
+**  wrapper routines. In this case the user-data pointer passed to
+**  x1.xCreate should be a pointer to the Fts5TokenizerModule structure,
+**  not a copy of pUserData.
+**
+**  Of course, if bV2Native is false, then x1 contains the real routines and
+**  x2 the synthesized ones. In this case a pointer to the Fts5TokenizerModule
+**  object should be passed to x2.xCreate.
+**
+**  The synthesized wrapper routines are necessary for xFindTokenizer(_v2)
+**  calls.
+*/
+struct Fts5TokenizerModule {
+  char *zName;                    /* Name of tokenizer */
+  void *pUserData;                /* User pointer passed to xCreate() */
+  int bV2Native;                  /* True if v2 native tokenizer */
+  fts5_tokenizer x1;              /* Tokenizer functions */
+  fts5_tokenizer_v2 x2;           /* V2 tokenizer functions */
+  void (*xDestroy)(void*);        /* Destructor function */
+  Fts5TokenizerModule *pNext;     /* Next registered tokenizer module */
+};
+
+struct Fts5FullTable {
+  Fts5Table p;                    /* Public class members from fts5Int.h */
+  Fts5Storage *pStorage;          /* Document store */
+  Fts5Global *pGlobal;            /* Global (connection wide) data */
+  Fts5Cursor *pSortCsr;           /* Sort data from this cursor */
+  int iSavepoint;                 /* Successful xSavepoint()+1 */
+
+#ifdef SQLITE_DEBUG
+  struct Fts5TransactionState ts;
+#endif
+};
+
+struct Fts5MatchPhrase {
+  Fts5Buffer *pPoslist;           /* Pointer to current poslist */
+  int nTerm;                      /* Size of phrase in terms */
+};
+
+/*
+** pStmt:
+**   SELECT rowid, <fts> FROM <fts> ORDER BY +rank;
+**
+** aIdx[]:
+**   There is one entry in the aIdx[] array for each phrase in the query,
+**   the value of which is the offset within aPoslist[] following the last
+**   byte of the position list for the corresponding phrase.
+*/
+struct Fts5Sorter {
+  sqlite3_stmt *pStmt;
+  i64 iRowid;                     /* Current rowid */
+  const u8 *aPoslist;             /* Position lists for current row */
+  int nIdx;                       /* Number of entries in aIdx[] */
+  int aIdx[1];                    /* Offsets into aPoslist for current row */
+};
+
+
+/*
+** Virtual-table cursor object.
+**
+** iSpecial:
+**   If this is a 'special' query (refer to function fts5SpecialMatch()),
+**   then this variable contains the result of the query.
+**
+** iFirstRowid, iLastRowid:
+**   These variables are only used for FTS5_PLAN_MATCH cursors. Assuming the
+**   cursor iterates in ascending order of rowids, iFirstRowid is the lower
+**   limit of rowids to return, and iLastRowid the upper. In other words, the
+**   WHERE clause in the user's query might have been:
+**
+**       <tbl> MATCH <expr> AND rowid BETWEEN $iFirstRowid AND $iLastRowid
+**
+**   If the cursor iterates in descending order of rowid, iFirstRowid
+**   is the upper limit (i.e. the "first" rowid visited) and iLastRowid
+**   the lower.
+*/
+struct Fts5Cursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  Fts5Cursor *pNext;              /* Next cursor in Fts5Cursor.pCsr list */
+  int *aColumnSize;               /* Values for xColumnSize() */
+  i64 iCsrId;                     /* Cursor id */
+
+  /* Zero from this point onwards on cursor reset */
+  int ePlan;                      /* FTS5_PLAN_XXX value */
+  int bDesc;                      /* True for "ORDER BY rowid DESC" queries */
+  i64 iFirstRowid;                /* Return no rowids earlier than this */
+  i64 iLastRowid;                 /* Return no rowids later than this */
+  sqlite3_stmt *pStmt;            /* Statement used to read %_content */
+  Fts5Expr *pExpr;                /* Expression for MATCH queries */
+  Fts5Sorter *pSorter;            /* Sorter for "ORDER BY rank" queries */
+  int csrflags;                   /* Mask of cursor flags (see below) */
+  i64 iSpecial;                   /* Result of special query */
+
+  /* "rank" function. Populated on demand from vtab.xColumn(). */
+  char *zRank;                    /* Custom rank function */
+  char *zRankArgs;                /* Custom rank function args */
+  Fts5Auxiliary *pRank;           /* Rank callback (or NULL) */
+  int nRankArg;                   /* Number of trailing arguments for rank() */
+  sqlite3_value **apRankArg;      /* Array of trailing arguments */
+  sqlite3_stmt *pRankArgStmt;     /* Origin of objects in apRankArg[] */
+
+  /* Auxiliary data storage */
+  Fts5Auxiliary *pAux;            /* Currently executing extension function */
+  Fts5Auxdata *pAuxdata;          /* First in linked list of saved aux-data */
+
+  /* Cache used by auxiliary API functions xInst() and xInstCount() */
+  Fts5PoslistReader *aInstIter;   /* One for each phrase */
+  int nInstAlloc;                 /* Size of aInst[] array (entries / 3) */
+  int nInstCount;                 /* Number of phrase instances */
+  int *aInst;                     /* 3 integers per phrase instance */
+};
+
+/*
+** Bits that make up the "idxNum" parameter passed indirectly by
+** xBestIndex() to xFilter().
+*/
+#define FTS5_BI_MATCH        0x0001         /* <tbl> MATCH ? */
+#define FTS5_BI_RANK         0x0002         /* rank MATCH ? */
+#define FTS5_BI_ROWID_EQ     0x0004         /* rowid == ? */
+#define FTS5_BI_ROWID_LE     0x0008         /* rowid <= ? */
+#define FTS5_BI_ROWID_GE     0x0010         /* rowid >= ? */
+
+#define FTS5_BI_ORDER_RANK   0x0020
+#define FTS5_BI_ORDER_ROWID  0x0040
+#define FTS5_BI_ORDER_DESC   0x0080
+
+/*
+** Values for Fts5Cursor.csrflags
+*/
+#define FTS5CSR_EOF               0x01
+#define FTS5CSR_REQUIRE_CONTENT   0x02
+#define FTS5CSR_REQUIRE_DOCSIZE   0x04
+#define FTS5CSR_REQUIRE_INST      0x08
+#define FTS5CSR_FREE_ZRANK        0x10
+#define FTS5CSR_REQUIRE_RESEEK    0x20
+#define FTS5CSR_REQUIRE_POSLIST   0x40
+
+#define BitFlagAllTest(x,y) (((x) & (y))==(y))
+#define BitFlagTest(x,y)    (((x) & (y))!=0)
+
+
+/*
+** Macros to Set(), Clear() and Test() cursor flags.
+*/
+#define CsrFlagSet(pCsr, flag)   ((pCsr)->csrflags |= (flag))
+#define CsrFlagClear(pCsr, flag) ((pCsr)->csrflags &= ~(flag))
+#define CsrFlagTest(pCsr, flag)  ((pCsr)->csrflags & (flag))
+
+struct Fts5Auxdata {
+  Fts5Auxiliary *pAux;            /* Extension to which this belongs */
+  void *pPtr;                     /* Pointer value */
+  void(*xDelete)(void*);          /* Destructor */
+  Fts5Auxdata *pNext;             /* Next object in linked list */
+};
+
+#ifdef SQLITE_DEBUG
+#define FTS5_BEGIN      1
+#define FTS5_SYNC       2
+#define FTS5_COMMIT     3
+#define FTS5_ROLLBACK   4
+#define FTS5_SAVEPOINT  5
+#define FTS5_RELEASE    6
+#define FTS5_ROLLBACKTO 7
+static void fts5CheckTransactionState(Fts5FullTable *p, int op, int iSavepoint){
+  switch( op ){
+    case FTS5_BEGIN:
+      assert( p->ts.eState==0 );
+      p->ts.eState = 1;
+      p->ts.iSavepoint = -1;
+      break;
+
+    case FTS5_SYNC:
+      assert( p->ts.eState==1 || p->ts.eState==2 );
+      p->ts.eState = 2;
+      break;
+
+    case FTS5_COMMIT:
+      assert( p->ts.eState==2 );
+      p->ts.eState = 0;
+      break;
+
+    case FTS5_ROLLBACK:
+      assert( p->ts.eState==1 || p->ts.eState==2 || p->ts.eState==0 );
+      p->ts.eState = 0;
+      break;
+
+    case FTS5_SAVEPOINT:
+      assert( p->ts.eState>=1 );
+      assert( iSavepoint>=0 );
+      assert( iSavepoint>=p->ts.iSavepoint );
+      p->ts.iSavepoint = iSavepoint;
+      break;
+
+    case FTS5_RELEASE:
+      assert( p->ts.eState>=1 );
+      assert( iSavepoint>=0 );
+      assert( iSavepoint<=p->ts.iSavepoint );
+      p->ts.iSavepoint = iSavepoint-1;
+      break;
+
+    case FTS5_ROLLBACKTO:
+      assert( p->ts.eState>=1 );
+      assert( iSavepoint>=-1 );
+      /* The following assert() can fail if another vtab strikes an error
+      ** within an xSavepoint() call then SQLite calls xRollbackTo() - without
+      ** having called xSavepoint() on this vtab.  */
+      /* assert( iSavepoint<=p->ts.iSavepoint ); */
+      p->ts.iSavepoint = iSavepoint;
+      break;
+  }
+}
+#else
+# define fts5CheckTransactionState(x,y,z)
+#endif
+
+/*
+** Return true if pTab is a contentless table. If parameter bIncludeUnindexed
+** is true, this includes contentless tables that store UNINDEXED columns
+** only.
+*/
+static int fts5IsContentless(Fts5FullTable *pTab, int bIncludeUnindexed){
+  int eContent = pTab->p.pConfig->eContent;
+  return (
+    eContent==FTS5_CONTENT_NONE
+    || (bIncludeUnindexed && eContent==FTS5_CONTENT_UNINDEXED)
+  );
+}
+
+/*
+** Delete a virtual table handle allocated by fts5InitVtab().
+*/
+static void fts5FreeVtab(Fts5FullTable *pTab){
+  if( pTab ){
+    sqlite3Fts5IndexClose(pTab->p.pIndex);
+    sqlite3Fts5StorageClose(pTab->pStorage);
+    sqlite3Fts5ConfigFree(pTab->p.pConfig);
+    sqlite3_free(pTab);
+  }
+}
+
+/*
+** The xDisconnect() virtual table method.
+*/
+static int fts5DisconnectMethod(sqlite3_vtab *pVtab){
+  fts5FreeVtab((Fts5FullTable*)pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** The xDestroy() virtual table method.
+*/
+static int fts5DestroyMethod(sqlite3_vtab *pVtab){
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  int rc = sqlite3Fts5DropAll(pTab->pConfig);
+  if( rc==SQLITE_OK ){
+    fts5FreeVtab((Fts5FullTable*)pVtab);
+  }
+  return rc;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the FTS3 virtual table.
+**
+** The argv[] array contains the following:
+**
+**   argv[0]   -> module name  ("fts5")
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> "column name" and other module argument fields.
+*/
+static int fts5InitVtab(
+  int bCreate,                    /* True for xCreate, false for xConnect */
+  sqlite3 *db,                    /* The SQLite database connection */
+  void *pAux,                     /* Hash table containing tokenizers */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
+  char **pzErr                    /* Write any error message here */
+){
+  Fts5Global *pGlobal = (Fts5Global*)pAux;
+  const char **azConfig = (const char**)argv;
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5Config *pConfig = 0;        /* Results of parsing argc/argv */
+  Fts5FullTable *pTab = 0;        /* New virtual table object */
+
+  /* Allocate the new vtab object and parse the configuration */
+  pTab = (Fts5FullTable*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5FullTable));
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ConfigParse(pGlobal, db, argc, azConfig, &pConfig, pzErr);
+    assert( (rc==SQLITE_OK && *pzErr==0) || pConfig==0 );
+  }
+  if( rc==SQLITE_OK ){
+    pConfig->pzErrmsg = pzErr;
+    pTab->p.pConfig = pConfig;
+    pTab->pGlobal = pGlobal;
+    if( bCreate || sqlite3Fts5TokenizerPreload(&pConfig->t) ){
+      rc = sqlite3Fts5LoadTokenizer(pConfig);
+    }
+  }
+
+  /* Open the index sub-system */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexOpen(pConfig, bCreate, &pTab->p.pIndex, pzErr);
+  }
+
+  /* Open the storage sub-system */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageOpen(
+        pConfig, pTab->p.pIndex, bCreate, &pTab->pStorage, pzErr
+    );
+  }
+
+  /* Call sqlite3_declare_vtab() */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ConfigDeclareVtab(pConfig);
+  }
+
+  /* Load the initial configuration */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ConfigLoad(pTab->p.pConfig, pTab->p.pConfig->iCookie-1);
+  }
+
+  if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_NORMAL ){
+    rc = sqlite3_vtab_config(db, SQLITE_VTAB_CONSTRAINT_SUPPORT, (int)1);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
+  }
+
+  if( pConfig ) pConfig->pzErrmsg = 0;
+  if( rc!=SQLITE_OK ){
+    fts5FreeVtab(pTab);
+    pTab = 0;
+  }else if( bCreate ){
+    fts5CheckTransactionState(pTab, FTS5_BEGIN, 0);
+  }
+  *ppVTab = (sqlite3_vtab*)pTab;
+  return rc;
+}
+
+/*
+** The xConnect() and xCreate() methods for the virtual table. All the
+** work is done in function fts5InitVtab().
+*/
+static int fts5ConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr);
+}
+static int fts5CreateMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr);
+}
+
+/*
+** The different query plans.
+*/
+#define FTS5_PLAN_MATCH          1       /* (<tbl> MATCH ?) */
+#define FTS5_PLAN_SOURCE         2       /* A source cursor for SORTED_MATCH */
+#define FTS5_PLAN_SPECIAL        3       /* An internal query */
+#define FTS5_PLAN_SORTED_MATCH   4       /* (<tbl> MATCH ? ORDER BY rank) */
+#define FTS5_PLAN_SCAN           5       /* No usable constraint */
+#define FTS5_PLAN_ROWID          6       /* (rowid = ?) */
+
+/*
+** Set the SQLITE_INDEX_SCAN_UNIQUE flag in pIdxInfo->flags. Unless this
+** extension is currently being used by a version of SQLite too old to
+** support index-info flags. In that case this function is a no-op.
+*/
+static void fts5SetUniqueFlag(sqlite3_index_info *pIdxInfo){
+#if SQLITE_VERSION_NUMBER>=3008012
+#ifndef SQLITE_CORE
+  if( sqlite3_libversion_number()>=3008012 )
+#endif
+  {
+    pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_UNIQUE;
+  }
+#endif
+}
+
+static int fts5UsePatternMatch(
+  Fts5Config *pConfig,
+  struct sqlite3_index_constraint *p
+){
+  assert( FTS5_PATTERN_GLOB==SQLITE_INDEX_CONSTRAINT_GLOB );
+  assert( FTS5_PATTERN_LIKE==SQLITE_INDEX_CONSTRAINT_LIKE );
+  if( pConfig->t.ePattern==FTS5_PATTERN_GLOB && p->op==FTS5_PATTERN_GLOB ){
+    return 1;
+  }
+  if( pConfig->t.ePattern==FTS5_PATTERN_LIKE
+   && (p->op==FTS5_PATTERN_LIKE || p->op==FTS5_PATTERN_GLOB)
+  ){
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Implementation of the xBestIndex method for FTS5 tables. Within the
+** WHERE constraint, it searches for the following:
+**
+**   1. A MATCH constraint against the table column.
+**   2. A MATCH constraint against the "rank" column.
+**   3. A MATCH constraint against some other column.
+**   4. An == constraint against the rowid column.
+**   5. A < or <= constraint against the rowid column.
+**   6. A > or >= constraint against the rowid column.
+**
+** Within the ORDER BY, the following are supported:
+**
+**   5. ORDER BY rank [ASC|DESC]
+**   6. ORDER BY rowid [ASC|DESC]
+**
+** Information for the xFilter call is passed via both the idxNum and
+** idxStr variables. Specifically, idxNum is a bitmask of the following
+** flags used to encode the ORDER BY clause:
+**
+**     FTS5_BI_ORDER_RANK
+**     FTS5_BI_ORDER_ROWID
+**     FTS5_BI_ORDER_DESC
+**
+** idxStr is used to encode data from the WHERE clause. For each argument
+** passed to the xFilter method, the following is appended to idxStr:
+**
+**   Match against table column:            "m"
+**   Match against rank column:             "r"
+**   Match against other column:            "M<column-number>"
+**   LIKE  against other column:            "L<column-number>"
+**   GLOB  against other column:            "G<column-number>"
+**   Equality constraint against the rowid: "="
+**   A < or <= against the rowid:           "<"
+**   A > or >= against the rowid:           ">"
+**
+** This function ensures that there is at most one "r" or "=". And that if
+** there exists an "=" then there is no "<" or ">".
+**
+** If an unusable MATCH operator is present in the WHERE clause, then
+** SQLITE_CONSTRAINT is returned.
+**
+** Costs are assigned as follows:
+**
+**  a) If a MATCH operator is present, the cost depends on the other
+**     constraints also present. As follows:
+**
+**       * No other constraints:         cost=1000.0
+**       * One rowid range constraint:   cost=750.0
+**       * Both rowid range constraints: cost=500.0
+**       * An == rowid constraint:       cost=100.0
+**
+**  b) Otherwise, if there is no MATCH:
+**
+**       * No other constraints:         cost=1000000.0
+**       * One rowid range constraint:   cost=750000.0
+**       * Both rowid range constraints: cost=250000.0
+**       * An == rowid constraint:       cost=10.0
+**
+** Costs are not modified by the ORDER BY clause.
+*/
+static int fts5BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
+  Fts5Table *pTab = (Fts5Table*)pVTab;
+  Fts5Config *pConfig = pTab->pConfig;
+  const int nCol = pConfig->nCol;
+  int idxFlags = 0;               /* Parameter passed through to xFilter() */
+  int i;
+
+  char *idxStr;
+  int iIdxStr = 0;
+  int iCons = 0;
+
+  int bSeenEq = 0;
+  int bSeenGt = 0;
+  int bSeenLt = 0;
+  int nSeenMatch = 0;
+  int bSeenRank = 0;
+
+
+  assert( SQLITE_INDEX_CONSTRAINT_EQ<SQLITE_INDEX_CONSTRAINT_MATCH );
+  assert( SQLITE_INDEX_CONSTRAINT_GT<SQLITE_INDEX_CONSTRAINT_MATCH );
+  assert( SQLITE_INDEX_CONSTRAINT_LE<SQLITE_INDEX_CONSTRAINT_MATCH );
+  assert( SQLITE_INDEX_CONSTRAINT_GE<SQLITE_INDEX_CONSTRAINT_MATCH );
+  assert( SQLITE_INDEX_CONSTRAINT_LE<SQLITE_INDEX_CONSTRAINT_MATCH );
+
+  if( pConfig->bLock ){
+    pTab->base.zErrMsg = sqlite3_mprintf(
+        "recursively defined fts5 content table"
+    );
+    return SQLITE_ERROR;
+  }
+
+  idxStr = (char*)sqlite3_malloc(pInfo->nConstraint * 8 + 1);
+  if( idxStr==0 ) return SQLITE_NOMEM;
+  pInfo->idxStr = idxStr;
+  pInfo->needToFreeIdxStr = 1;
+
+  for(i=0; i<pInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *p = &pInfo->aConstraint[i];
+    int iCol = p->iColumn;
+    if( p->op==SQLITE_INDEX_CONSTRAINT_MATCH
+     || (p->op==SQLITE_INDEX_CONSTRAINT_EQ && iCol>=nCol)
+    ){
+      /* A MATCH operator or equivalent */
+      if( p->usable==0 || iCol<0 ){
+        /* As there exists an unusable MATCH constraint this is an
+        ** unusable plan. Return SQLITE_CONSTRAINT. */
+        idxStr[iIdxStr] = 0;
+        return SQLITE_CONSTRAINT;
+      }else{
+        if( iCol==nCol+1 ){
+          if( bSeenRank ) continue;
+          idxStr[iIdxStr++] = 'r';
+          bSeenRank = 1;
+        }else{
+          nSeenMatch++;
+          idxStr[iIdxStr++] = 'M';
+          sqlite3_snprintf(6, &idxStr[iIdxStr], "%d", iCol);
+          idxStr += strlen(&idxStr[iIdxStr]);
+          assert( idxStr[iIdxStr]=='\0' );
+        }
+        pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+        pInfo->aConstraintUsage[i].omit = 1;
+      }
+    }else if( p->usable ){
+      if( iCol>=0 && iCol<nCol && fts5UsePatternMatch(pConfig, p) ){
+        assert( p->op==FTS5_PATTERN_LIKE || p->op==FTS5_PATTERN_GLOB );
+        idxStr[iIdxStr++] = p->op==FTS5_PATTERN_LIKE ? 'L' : 'G';
+        sqlite3_snprintf(6, &idxStr[iIdxStr], "%d", iCol);
+        idxStr += strlen(&idxStr[iIdxStr]);
+        pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+        assert( idxStr[iIdxStr]=='\0' );
+        nSeenMatch++;
+      }else if( bSeenEq==0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ && iCol<0 ){
+        idxStr[iIdxStr++] = '=';
+        bSeenEq = 1;
+        pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+      }
+    }
+  }
+
+  if( bSeenEq==0 ){
+    for(i=0; i<pInfo->nConstraint; i++){
+      struct sqlite3_index_constraint *p = &pInfo->aConstraint[i];
+      if( p->iColumn<0 && p->usable ){
+        int op = p->op;
+        if( op==SQLITE_INDEX_CONSTRAINT_LT || op==SQLITE_INDEX_CONSTRAINT_LE ){
+          if( bSeenLt ) continue;
+          idxStr[iIdxStr++] = '<';
+          pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+          bSeenLt = 1;
+        }else
+        if( op==SQLITE_INDEX_CONSTRAINT_GT || op==SQLITE_INDEX_CONSTRAINT_GE ){
+          if( bSeenGt ) continue;
+          idxStr[iIdxStr++] = '>';
+          pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+          bSeenGt = 1;
+        }
+      }
+    }
+  }
+  idxStr[iIdxStr] = '\0';
+
+  /* Set idxFlags flags for the ORDER BY clause
+  **
+  ** Note that tokendata=1 tables cannot currently handle "ORDER BY rowid DESC".
+  */
+  if( pInfo->nOrderBy==1 ){
+    int iSort = pInfo->aOrderBy[0].iColumn;
+    if( iSort==(pConfig->nCol+1) && nSeenMatch>0 ){
+      idxFlags |= FTS5_BI_ORDER_RANK;
+    }else if( iSort==-1 && (!pInfo->aOrderBy[0].desc || !pConfig->bTokendata) ){
+      idxFlags |= FTS5_BI_ORDER_ROWID;
+    }
+    if( BitFlagTest(idxFlags, FTS5_BI_ORDER_RANK|FTS5_BI_ORDER_ROWID) ){
+      pInfo->orderByConsumed = 1;
+      if( pInfo->aOrderBy[0].desc ){
+        idxFlags |= FTS5_BI_ORDER_DESC;
+      }
+    }
+  }
+
+  /* Calculate the estimated cost based on the flags set in idxFlags. */
+  if( bSeenEq ){
+    pInfo->estimatedCost = nSeenMatch ? 1000.0 : 10.0;
+    if( nSeenMatch==0 ) fts5SetUniqueFlag(pInfo);
+  }else if( bSeenLt && bSeenGt ){
+    pInfo->estimatedCost = nSeenMatch ? 5000.0 : 250000.0;
+  }else if( bSeenLt || bSeenGt ){
+    pInfo->estimatedCost = nSeenMatch ? 7500.0 : 750000.0;
+  }else{
+    pInfo->estimatedCost = nSeenMatch ? 10000.0 : 1000000.0;
+  }
+  for(i=1; i<nSeenMatch; i++){
+    pInfo->estimatedCost *= 0.4;
+  }
+
+  pInfo->idxNum = idxFlags;
+  return SQLITE_OK;
+}
+
+static int fts5NewTransaction(Fts5FullTable *pTab){
+  Fts5Cursor *pCsr;
+  for(pCsr=pTab->pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
+    if( pCsr->base.pVtab==(sqlite3_vtab*)pTab ) return SQLITE_OK;
+  }
+  return sqlite3Fts5StorageReset(pTab->pStorage);
+}
+
+/*
+** Implementation of xOpen method.
+*/
+static int fts5OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVTab;
+  Fts5Config *pConfig = pTab->p.pConfig;
+  Fts5Cursor *pCsr = 0;           /* New cursor object */
+  sqlite3_int64 nByte;            /* Bytes of space to allocate */
+  int rc;                         /* Return code */
+
+  rc = fts5NewTransaction(pTab);
+  if( rc==SQLITE_OK ){
+    nByte = sizeof(Fts5Cursor) + pConfig->nCol * sizeof(int);
+    pCsr = (Fts5Cursor*)sqlite3_malloc64(nByte);
+    if( pCsr ){
+      Fts5Global *pGlobal = pTab->pGlobal;
+      memset(pCsr, 0, (size_t)nByte);
+      pCsr->aColumnSize = (int*)&pCsr[1];
+      pCsr->pNext = pGlobal->pCsr;
+      pGlobal->pCsr = pCsr;
+      pCsr->iCsrId = ++pGlobal->iNextId;
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
+  return rc;
+}
+
+static int fts5StmtType(Fts5Cursor *pCsr){
+  if( pCsr->ePlan==FTS5_PLAN_SCAN ){
+    return (pCsr->bDesc) ? FTS5_STMT_SCAN_DESC : FTS5_STMT_SCAN_ASC;
+  }
+  return FTS5_STMT_LOOKUP;
+}
+
+/*
+** This function is called after the cursor passed as the only argument
+** is moved to point at a different row. It clears all cached data
+** specific to the previous row stored by the cursor object.
+*/
+static void fts5CsrNewrow(Fts5Cursor *pCsr){
+  CsrFlagSet(pCsr,
+      FTS5CSR_REQUIRE_CONTENT
+    | FTS5CSR_REQUIRE_DOCSIZE
+    | FTS5CSR_REQUIRE_INST
+    | FTS5CSR_REQUIRE_POSLIST
+  );
+}
+
+static void fts5FreeCursorComponents(Fts5Cursor *pCsr){
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  Fts5Auxdata *pData;
+  Fts5Auxdata *pNext;
+
+  sqlite3_free(pCsr->aInstIter);
+  sqlite3_free(pCsr->aInst);
+  if( pCsr->pStmt ){
+    int eStmt = fts5StmtType(pCsr);
+    sqlite3Fts5StorageStmtRelease(pTab->pStorage, eStmt, pCsr->pStmt);
+  }
+  if( pCsr->pSorter ){
+    Fts5Sorter *pSorter = pCsr->pSorter;
+    sqlite3_finalize(pSorter->pStmt);
+    sqlite3_free(pSorter);
+  }
+
+  if( pCsr->ePlan!=FTS5_PLAN_SOURCE ){
+    sqlite3Fts5ExprFree(pCsr->pExpr);
+  }
+
+  for(pData=pCsr->pAuxdata; pData; pData=pNext){
+    pNext = pData->pNext;
+    if( pData->xDelete ) pData->xDelete(pData->pPtr);
+    sqlite3_free(pData);
+  }
+
+  sqlite3_finalize(pCsr->pRankArgStmt);
+  sqlite3_free(pCsr->apRankArg);
+
+  if( CsrFlagTest(pCsr, FTS5CSR_FREE_ZRANK) ){
+    sqlite3_free(pCsr->zRank);
+    sqlite3_free(pCsr->zRankArgs);
+  }
+
+  sqlite3Fts5IndexCloseReader(pTab->p.pIndex);
+  memset(&pCsr->ePlan, 0, sizeof(Fts5Cursor) - ((u8*)&pCsr->ePlan - (u8*)pCsr));
+}
+
+
+/*
+** Close the cursor.  For additional information see the documentation
+** on the xClose method of the virtual table interface.
+*/
+static int fts5CloseMethod(sqlite3_vtab_cursor *pCursor){
+  if( pCursor ){
+    Fts5FullTable *pTab = (Fts5FullTable*)(pCursor->pVtab);
+    Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+    Fts5Cursor **pp;
+
+    fts5FreeCursorComponents(pCsr);
+    /* Remove the cursor from the Fts5Global.pCsr list */
+    for(pp=&pTab->pGlobal->pCsr; (*pp)!=pCsr; pp=&(*pp)->pNext);
+    *pp = pCsr->pNext;
+
+    sqlite3_free(pCsr);
+  }
+  return SQLITE_OK;
+}
+
+static int fts5SorterNext(Fts5Cursor *pCsr){
+  Fts5Sorter *pSorter = pCsr->pSorter;
+  int rc;
+
+  rc = sqlite3_step(pSorter->pStmt);
+  if( rc==SQLITE_DONE ){
+    rc = SQLITE_OK;
+    CsrFlagSet(pCsr, FTS5CSR_EOF|FTS5CSR_REQUIRE_CONTENT);
+  }else if( rc==SQLITE_ROW ){
+    const u8 *a;
+    const u8 *aBlob;
+    int nBlob;
+    int i;
+    int iOff = 0;
+    rc = SQLITE_OK;
+
+    pSorter->iRowid = sqlite3_column_int64(pSorter->pStmt, 0);
+    nBlob = sqlite3_column_bytes(pSorter->pStmt, 1);
+    aBlob = a = sqlite3_column_blob(pSorter->pStmt, 1);
+
+    /* nBlob==0 in detail=none mode. */
+    if( nBlob>0 ){
+      for(i=0; i<(pSorter->nIdx-1); i++){
+        int iVal;
+        a += fts5GetVarint32(a, iVal);
+        iOff += iVal;
+        pSorter->aIdx[i] = iOff;
+      }
+      pSorter->aIdx[i] = &aBlob[nBlob] - a;
+      pSorter->aPoslist = a;
+    }
+
+    fts5CsrNewrow(pCsr);
+  }
+
+  return rc;
+}
+
+
+/*
+** Set the FTS5CSR_REQUIRE_RESEEK flag on all FTS5_PLAN_MATCH cursors
+** open on table pTab.
+*/
+static void fts5TripCursors(Fts5FullTable *pTab){
+  Fts5Cursor *pCsr;
+  for(pCsr=pTab->pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
+    if( pCsr->ePlan==FTS5_PLAN_MATCH
+     && pCsr->base.pVtab==(sqlite3_vtab*)pTab
+    ){
+      CsrFlagSet(pCsr, FTS5CSR_REQUIRE_RESEEK);
+    }
+  }
+}
+
+/*
+** If the REQUIRE_RESEEK flag is set on the cursor passed as the first
+** argument, close and reopen all Fts5IndexIter iterators that the cursor
+** is using. Then attempt to move the cursor to a rowid equal to or laster
+** (in the cursors sort order - ASC or DESC) than the current rowid.
+**
+** If the new rowid is not equal to the old, set output parameter *pbSkip
+** to 1 before returning. Otherwise, leave it unchanged.
+**
+** Return SQLITE_OK if successful or if no reseek was required, or an
+** error code if an error occurred.
+*/
+static int fts5CursorReseek(Fts5Cursor *pCsr, int *pbSkip){
+  int rc = SQLITE_OK;
+  assert( *pbSkip==0 );
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_RESEEK) ){
+    Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+    int bDesc = pCsr->bDesc;
+    i64 iRowid = sqlite3Fts5ExprRowid(pCsr->pExpr);
+
+    rc = sqlite3Fts5ExprFirst(pCsr->pExpr, pTab->p.pIndex, iRowid, bDesc);
+    if( rc==SQLITE_OK &&  iRowid!=sqlite3Fts5ExprRowid(pCsr->pExpr) ){
+      *pbSkip = 1;
+    }
+
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_RESEEK);
+    fts5CsrNewrow(pCsr);
+    if( sqlite3Fts5ExprEof(pCsr->pExpr) ){
+      CsrFlagSet(pCsr, FTS5CSR_EOF);
+      *pbSkip = 1;
+    }
+  }
+  return rc;
+}
+
+
+/*
+** Advance the cursor to the next row in the table that matches the
+** search criteria.
+**
+** Return SQLITE_OK if nothing goes wrong.  SQLITE_OK is returned
+** even if we reach end-of-file.  The fts5EofMethod() will be called
+** subsequently to determine whether or not an EOF was hit.
+*/
+static int fts5NextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int rc;
+
+  assert( (pCsr->ePlan<3)==
+          (pCsr->ePlan==FTS5_PLAN_MATCH || pCsr->ePlan==FTS5_PLAN_SOURCE)
+  );
+  assert( !CsrFlagTest(pCsr, FTS5CSR_EOF) );
+
+  /* If this cursor uses FTS5_PLAN_MATCH and this is a tokendata=1 table,
+  ** clear any token mappings accumulated at the fts5_index.c level. In
+  ** other cases, specifically FTS5_PLAN_SOURCE and FTS5_PLAN_SORTED_MATCH,
+  ** we need to retain the mappings for the entire query.  */
+  if( pCsr->ePlan==FTS5_PLAN_MATCH
+   && ((Fts5Table*)pCursor->pVtab)->pConfig->bTokendata
+  ){
+    sqlite3Fts5ExprClearTokens(pCsr->pExpr);
+  }
+
+  if( pCsr->ePlan<3 ){
+    int bSkip = 0;
+    if( (rc = fts5CursorReseek(pCsr, &bSkip)) || bSkip ) return rc;
+    rc = sqlite3Fts5ExprNext(pCsr->pExpr, pCsr->iLastRowid);
+    CsrFlagSet(pCsr, sqlite3Fts5ExprEof(pCsr->pExpr));
+    fts5CsrNewrow(pCsr);
+  }else{
+    switch( pCsr->ePlan ){
+      case FTS5_PLAN_SPECIAL: {
+        CsrFlagSet(pCsr, FTS5CSR_EOF);
+        rc = SQLITE_OK;
+        break;
+      }
+
+      case FTS5_PLAN_SORTED_MATCH: {
+        rc = fts5SorterNext(pCsr);
+        break;
+      }
+
+      default: {
+        Fts5Config *pConfig = ((Fts5Table*)pCursor->pVtab)->pConfig;
+        pConfig->bLock++;
+        rc = sqlite3_step(pCsr->pStmt);
+        pConfig->bLock--;
+        if( rc!=SQLITE_ROW ){
+          CsrFlagSet(pCsr, FTS5CSR_EOF);
+          rc = sqlite3_reset(pCsr->pStmt);
+          if( rc!=SQLITE_OK ){
+            pCursor->pVtab->zErrMsg = sqlite3_mprintf(
+                "%s", sqlite3_errmsg(pConfig->db)
+            );
+          }
+        }else{
+          rc = SQLITE_OK;
+          CsrFlagSet(pCsr, FTS5CSR_REQUIRE_DOCSIZE);
+        }
+        break;
+      }
+    }
+  }
+
+  return rc;
+}
+
+
+static int fts5PrepareStatement(
+  sqlite3_stmt **ppStmt,
+  Fts5Config *pConfig,
+  const char *zFmt,
+  ...
+){
+  sqlite3_stmt *pRet = 0;
+  int rc;
+  char *zSql;
+  va_list ap;
+
+  va_start(ap, zFmt);
+  zSql = sqlite3_vmprintf(zFmt, ap);
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare_v3(pConfig->db, zSql, -1,
+                            SQLITE_PREPARE_PERSISTENT, &pRet, 0);
+    if( rc!=SQLITE_OK ){
+      sqlite3Fts5ConfigErrmsg(pConfig, "%s", sqlite3_errmsg(pConfig->db));
+    }
+    sqlite3_free(zSql);
+  }
+
+  va_end(ap);
+  *ppStmt = pRet;
+  return rc;
+}
+
+static int fts5CursorFirstSorted(
+  Fts5FullTable *pTab,
+  Fts5Cursor *pCsr,
+  int bDesc
+){
+  Fts5Config *pConfig = pTab->p.pConfig;
+  Fts5Sorter *pSorter;
+  int nPhrase;
+  sqlite3_int64 nByte;
+  int rc;
+  const char *zRank = pCsr->zRank;
+  const char *zRankArgs = pCsr->zRankArgs;
+
+  nPhrase = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+  nByte = sizeof(Fts5Sorter) + sizeof(int) * (nPhrase-1);
+  pSorter = (Fts5Sorter*)sqlite3_malloc64(nByte);
+  if( pSorter==0 ) return SQLITE_NOMEM;
+  memset(pSorter, 0, (size_t)nByte);
+  pSorter->nIdx = nPhrase;
+
+  /* TODO: It would be better to have some system for reusing statement
+  ** handles here, rather than preparing a new one for each query. But that
+  ** is not possible as SQLite reference counts the virtual table objects.
+  ** And since the statement required here reads from this very virtual
+  ** table, saving it creates a circular reference.
+  **
+  ** If SQLite a built-in statement cache, this wouldn't be a problem. */
+  rc = fts5PrepareStatement(&pSorter->pStmt, pConfig,
+      "SELECT rowid, rank FROM %Q.%Q ORDER BY %s(\"%w\"%s%s) %s",
+      pConfig->zDb, pConfig->zName, zRank, pConfig->zName,
+      (zRankArgs ? ", " : ""),
+      (zRankArgs ? zRankArgs : ""),
+      bDesc ? "DESC" : "ASC"
+  );
+
+  pCsr->pSorter = pSorter;
+  if( rc==SQLITE_OK ){
+    assert( pTab->pSortCsr==0 );
+    pTab->pSortCsr = pCsr;
+    rc = fts5SorterNext(pCsr);
+    pTab->pSortCsr = 0;
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_finalize(pSorter->pStmt);
+    sqlite3_free(pSorter);
+    pCsr->pSorter = 0;
+  }
+
+  return rc;
+}
+
+static int fts5CursorFirst(Fts5FullTable *pTab, Fts5Cursor *pCsr, int bDesc){
+  int rc;
+  Fts5Expr *pExpr = pCsr->pExpr;
+  rc = sqlite3Fts5ExprFirst(pExpr, pTab->p.pIndex, pCsr->iFirstRowid, bDesc);
+  if( sqlite3Fts5ExprEof(pExpr) ){
+    CsrFlagSet(pCsr, FTS5CSR_EOF);
+  }
+  fts5CsrNewrow(pCsr);
+  return rc;
+}
+
+/*
+** Process a "special" query. A special query is identified as one with a
+** MATCH expression that begins with a '*' character. The remainder of
+** the text passed to the MATCH operator are used as  the special query
+** parameters.
+*/
+static int fts5SpecialMatch(
+  Fts5FullTable *pTab,
+  Fts5Cursor *pCsr,
+  const char *zQuery
+){
+  int rc = SQLITE_OK;             /* Return code */
+  const char *z = zQuery;         /* Special query text */
+  int n;                          /* Number of bytes in text at z */
+
+  while( z[0]==' ' ) z++;
+  for(n=0; z[n] && z[n]!=' '; n++);
+
+  assert( pTab->p.base.zErrMsg==0 );
+  pCsr->ePlan = FTS5_PLAN_SPECIAL;
+
+  if( n==5 && 0==sqlite3_strnicmp("reads", z, n) ){
+    pCsr->iSpecial = sqlite3Fts5IndexReads(pTab->p.pIndex);
+  }
+  else if( n==2 && 0==sqlite3_strnicmp("id", z, n) ){
+    pCsr->iSpecial = pCsr->iCsrId;
+  }
+  else{
+    /* An unrecognized directive. Return an error message. */
+    pTab->p.base.zErrMsg = sqlite3_mprintf("unknown special query: %.*s", n, z);
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+/*
+** Search for an auxiliary function named zName that can be used with table
+** pTab. If one is found, return a pointer to the corresponding Fts5Auxiliary
+** structure. Otherwise, if no such function exists, return NULL.
+*/
+static Fts5Auxiliary *fts5FindAuxiliary(Fts5FullTable *pTab, const char *zName){
+  Fts5Auxiliary *pAux;
+
+  for(pAux=pTab->pGlobal->pAux; pAux; pAux=pAux->pNext){
+    if( sqlite3_stricmp(zName, pAux->zFunc)==0 ) return pAux;
+  }
+
+  /* No function of the specified name was found. Return 0. */
+  return 0;
+}
+
+
+static int fts5FindRankFunction(Fts5Cursor *pCsr){
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  Fts5Config *pConfig = pTab->p.pConfig;
+  int rc = SQLITE_OK;
+  Fts5Auxiliary *pAux = 0;
+  const char *zRank = pCsr->zRank;
+  const char *zRankArgs = pCsr->zRankArgs;
+
+  if( zRankArgs ){
+    char *zSql = sqlite3Fts5Mprintf(&rc, "SELECT %s", zRankArgs);
+    if( zSql ){
+      sqlite3_stmt *pStmt = 0;
+      rc = sqlite3_prepare_v3(pConfig->db, zSql, -1,
+                              SQLITE_PREPARE_PERSISTENT, &pStmt, 0);
+      sqlite3_free(zSql);
+      assert( rc==SQLITE_OK || pCsr->pRankArgStmt==0 );
+      if( rc==SQLITE_OK ){
+        if( SQLITE_ROW==sqlite3_step(pStmt) ){
+          sqlite3_int64 nByte;
+          pCsr->nRankArg = sqlite3_column_count(pStmt);
+          nByte = sizeof(sqlite3_value*)*pCsr->nRankArg;
+          pCsr->apRankArg = (sqlite3_value**)sqlite3Fts5MallocZero(&rc, nByte);
+          if( rc==SQLITE_OK ){
+            int i;
+            for(i=0; i<pCsr->nRankArg; i++){
+              pCsr->apRankArg[i] = sqlite3_column_value(pStmt, i);
+            }
+          }
+          pCsr->pRankArgStmt = pStmt;
+        }else{
+          rc = sqlite3_finalize(pStmt);
+          assert( rc!=SQLITE_OK );
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    pAux = fts5FindAuxiliary(pTab, zRank);
+    if( pAux==0 ){
+      assert( pTab->p.base.zErrMsg==0 );
+      pTab->p.base.zErrMsg = sqlite3_mprintf("no such function: %s", zRank);
+      rc = SQLITE_ERROR;
+    }
+  }
+
+  pCsr->pRank = pAux;
+  return rc;
+}
+
+
+static int fts5CursorParseRank(
+  Fts5Config *pConfig,
+  Fts5Cursor *pCsr,
+  sqlite3_value *pRank
+){
+  int rc = SQLITE_OK;
+  if( pRank ){
+    const char *z = (const char*)sqlite3_value_text(pRank);
+    char *zRank = 0;
+    char *zRankArgs = 0;
+
+    if( z==0 ){
+      if( sqlite3_value_type(pRank)==SQLITE_NULL ) rc = SQLITE_ERROR;
+    }else{
+      rc = sqlite3Fts5ConfigParseRank(z, &zRank, &zRankArgs);
+    }
+    if( rc==SQLITE_OK ){
+      pCsr->zRank = zRank;
+      pCsr->zRankArgs = zRankArgs;
+      CsrFlagSet(pCsr, FTS5CSR_FREE_ZRANK);
+    }else if( rc==SQLITE_ERROR ){
+      pCsr->base.pVtab->zErrMsg = sqlite3_mprintf(
+          "parse error in rank function: %s", z
+      );
+    }
+  }else{
+    if( pConfig->zRank ){
+      pCsr->zRank = (char*)pConfig->zRank;
+      pCsr->zRankArgs = (char*)pConfig->zRankArgs;
+    }else{
+      pCsr->zRank = (char*)FTS5_DEFAULT_RANK;
+      pCsr->zRankArgs = 0;
+    }
+  }
+  return rc;
+}
+
+static i64 fts5GetRowidLimit(sqlite3_value *pVal, i64 iDefault){
+  if( pVal ){
+    int eType = sqlite3_value_numeric_type(pVal);
+    if( eType==SQLITE_INTEGER ){
+      return sqlite3_value_int64(pVal);
+    }
+  }
+  return iDefault;
+}
+
+/*
+** Set the error message on the virtual table passed as the first argument.
+*/
+static void fts5SetVtabError(Fts5FullTable *p, const char *zFormat, ...){
+  va_list ap;                     /* ... printf arguments */
+  va_start(ap, zFormat);
+  sqlite3_free(p->p.base.zErrMsg);
+  p->p.base.zErrMsg = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+}
+
+/*
+** Arrange for subsequent calls to sqlite3Fts5Tokenize() to use the locale
+** specified by pLocale/nLocale. The buffer indicated by pLocale must remain
+** valid until after the final call to sqlite3Fts5Tokenize() that will use
+** the locale.
+*/
+static void sqlite3Fts5SetLocale(
+  Fts5Config *pConfig,
+  const char *zLocale,
+  int nLocale
+){
+  Fts5TokenizerConfig *pT = &pConfig->t;
+  pT->pLocale = zLocale;
+  pT->nLocale = nLocale;
+}
+
+/*
+** Clear any locale configured by an earlier call to sqlite3Fts5SetLocale().
+*/
+static void sqlite3Fts5ClearLocale(Fts5Config *pConfig){
+  sqlite3Fts5SetLocale(pConfig, 0, 0);
+}
+
+/*
+** Return true if the value passed as the only argument is an
+** fts5_locale() value.
+*/
+static int sqlite3Fts5IsLocaleValue(Fts5Config *pConfig, sqlite3_value *pVal){
+  int ret = 0;
+  if( sqlite3_value_type(pVal)==SQLITE_BLOB ){
+    /* Call sqlite3_value_bytes() after sqlite3_value_blob() in this case.
+    ** If the blob was created using zeroblob(), then sqlite3_value_blob()
+    ** may call malloc(). If this malloc() fails, then the values returned
+    ** by both value_blob() and value_bytes() will be 0. If value_bytes() were
+    ** called first, then the NULL pointer returned by value_blob() might
+    ** be dereferenced.  */
+    const u8 *pBlob = sqlite3_value_blob(pVal);
+    int nBlob = sqlite3_value_bytes(pVal);
+    if( nBlob>FTS5_LOCALE_HDR_SIZE
+     && 0==memcmp(pBlob, FTS5_LOCALE_HDR(pConfig), FTS5_LOCALE_HDR_SIZE)
+    ){
+      ret = 1;
+    }
+  }
+  return ret;
+}
+
+/*
+** Value pVal is guaranteed to be an fts5_locale() value, according to
+** sqlite3Fts5IsLocaleValue(). This function extracts the text and locale
+** from the value and returns them separately.
+**
+** If successful, SQLITE_OK is returned and (*ppText) and (*ppLoc) set
+** to point to buffers containing the text and locale, as utf-8,
+** respectively. In this case output parameters (*pnText) and (*pnLoc) are
+** set to the sizes in bytes of these two buffers.
+**
+** Or, if an error occurs, then an SQLite error code is returned. The final
+** value of the four output parameters is undefined in this case.
+*/
+static int sqlite3Fts5DecodeLocaleValue(
+  sqlite3_value *pVal,
+  const char **ppText,
+  int *pnText,
+  const char **ppLoc,
+  int *pnLoc
+){
+  const char *p = sqlite3_value_blob(pVal);
+  int n = sqlite3_value_bytes(pVal);
+  int nLoc = 0;
+
+  assert( sqlite3_value_type(pVal)==SQLITE_BLOB );
+  assert( n>FTS5_LOCALE_HDR_SIZE );
+
+  for(nLoc=FTS5_LOCALE_HDR_SIZE; p[nLoc]; nLoc++){
+    if( nLoc==(n-1) ){
+      return SQLITE_MISMATCH;
+    }
+  }
+  *ppLoc = &p[FTS5_LOCALE_HDR_SIZE];
+  *pnLoc = nLoc - FTS5_LOCALE_HDR_SIZE;
+
+  *ppText = &p[nLoc+1];
+  *pnText = n - nLoc - 1;
+  return SQLITE_OK;
+}
+
+/*
+** Argument pVal is the text of a full-text search expression. It may or
+** may not have been wrapped by fts5_locale(). This function extracts
+** the text of the expression, and sets output variable (*pzText) to
+** point to a nul-terminated buffer containing the expression.
+**
+** If pVal was an fts5_locale() value, then sqlite3Fts5SetLocale() is called
+** to set the tokenizer to use the specified locale.
+**
+** If output variable (*pbFreeAndReset) is set to true, then the caller
+** is required to (a) call sqlite3Fts5ClearLocale() to reset the tokenizer
+** locale, and (b) call sqlite3_free() to free (*pzText).
+*/
+static int fts5ExtractExprText(
+  Fts5Config *pConfig,            /* Fts5 configuration */
+  sqlite3_value *pVal,            /* Value to extract expression text from */
+  char **pzText,                  /* OUT: nul-terminated buffer of text */
+  int *pbFreeAndReset             /* OUT: Free (*pzText) and clear locale */
+){
+  int rc = SQLITE_OK;
+
+  if( sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+    const char *pText = 0;
+    int nText = 0;
+    const char *pLoc = 0;
+    int nLoc = 0;
+    rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+    *pzText = sqlite3Fts5Mprintf(&rc, "%.*s", nText, pText);
+    if( rc==SQLITE_OK ){
+      sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+    }
+    *pbFreeAndReset = 1;
+  }else{
+    *pzText = (char*)sqlite3_value_text(pVal);
+    *pbFreeAndReset = 0;
+  }
+
+  return rc;
+}
+
+
+/*
+** This is the xFilter interface for the virtual table.  See
+** the virtual table xFilter method documentation for additional
+** information.
+**
+** There are three possible query strategies:
+**
+**   1. Full-text search using a MATCH operator.
+**   2. A by-rowid lookup.
+**   3. A full-table scan.
+*/
+static int fts5FilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCursor->pVtab);
+  Fts5Config *pConfig = pTab->p.pConfig;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int rc = SQLITE_OK;             /* Error code */
+  int bDesc;                      /* True if ORDER BY [rank|rowid] DESC */
+  int bOrderByRank;               /* True if ORDER BY rank */
+  sqlite3_value *pRank = 0;       /* rank MATCH ? expression (or NULL) */
+  sqlite3_value *pRowidEq = 0;    /* rowid = ? expression (or NULL) */
+  sqlite3_value *pRowidLe = 0;    /* rowid <= ? expression (or NULL) */
+  sqlite3_value *pRowidGe = 0;    /* rowid >= ? expression (or NULL) */
+  int iCol;                       /* Column on LHS of MATCH operator */
+  char **pzErrmsg = pConfig->pzErrmsg;
+  int bPrefixInsttoken = pConfig->bPrefixInsttoken;
+  int i;
+  int iIdxStr = 0;
+  Fts5Expr *pExpr = 0;
+
+  assert( pConfig->bLock==0 );
+  if( pCsr->ePlan ){
+    fts5FreeCursorComponents(pCsr);
+    memset(&pCsr->ePlan, 0, sizeof(Fts5Cursor) - ((u8*)&pCsr->ePlan-(u8*)pCsr));
+  }
+
+  assert( pCsr->pStmt==0 );
+  assert( pCsr->pExpr==0 );
+  assert( pCsr->csrflags==0 );
+  assert( pCsr->pRank==0 );
+  assert( pCsr->zRank==0 );
+  assert( pCsr->zRankArgs==0 );
+  assert( pTab->pSortCsr==0 || nVal==0 );
+
+  assert( pzErrmsg==0 || pzErrmsg==&pTab->p.base.zErrMsg );
+  pConfig->pzErrmsg = &pTab->p.base.zErrMsg;
+
+  /* Decode the arguments passed through to this function. */
+  for(i=0; i<nVal; i++){
+    switch( idxStr[iIdxStr++] ){
+      case 'r':
+        pRank = apVal[i];
+        break;
+      case 'M': {
+        char *zText = 0;
+        int bFreeAndReset = 0;
+        int bInternal = 0;
+
+        rc = fts5ExtractExprText(pConfig, apVal[i], &zText, &bFreeAndReset);
+        if( rc!=SQLITE_OK ) goto filter_out;
+        if( zText==0 ) zText = "";
+        if( sqlite3_value_subtype(apVal[i])==FTS5_INSTTOKEN_SUBTYPE ){
+          pConfig->bPrefixInsttoken = 1;
+        }
+
+        iCol = 0;
+        do{
+          iCol = iCol*10 + (idxStr[iIdxStr]-'0');
+          iIdxStr++;
+        }while( idxStr[iIdxStr]>='0' && idxStr[iIdxStr]<='9' );
+
+        if( zText[0]=='*' ){
+          /* The user has issued a query of the form "MATCH '*...'". This
+          ** indicates that the MATCH expression is not a full text query,
+          ** but a request for an internal parameter.  */
+          rc = fts5SpecialMatch(pTab, pCsr, &zText[1]);
+          bInternal = 1;
+        }else{
+          char **pzErr = &pTab->p.base.zErrMsg;
+          rc = sqlite3Fts5ExprNew(pConfig, 0, iCol, zText, &pExpr, pzErr);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5ExprAnd(&pCsr->pExpr, pExpr);
+            pExpr = 0;
+          }
+        }
+
+        if( bFreeAndReset ){
+          sqlite3_free(zText);
+          sqlite3Fts5ClearLocale(pConfig);
+        }
+
+        if( bInternal || rc!=SQLITE_OK ) goto filter_out;
+
+        break;
+      }
+      case 'L':
+      case 'G': {
+        int bGlob = (idxStr[iIdxStr-1]=='G');
+        const char *zText = (const char*)sqlite3_value_text(apVal[i]);
+        iCol = 0;
+        do{
+          iCol = iCol*10 + (idxStr[iIdxStr]-'0');
+          iIdxStr++;
+        }while( idxStr[iIdxStr]>='0' && idxStr[iIdxStr]<='9' );
+        if( zText ){
+          rc = sqlite3Fts5ExprPattern(pConfig, bGlob, iCol, zText, &pExpr);
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3Fts5ExprAnd(&pCsr->pExpr, pExpr);
+          pExpr = 0;
+        }
+        if( rc!=SQLITE_OK ) goto filter_out;
+        break;
+      }
+      case '=':
+        pRowidEq = apVal[i];
+        break;
+      case '<':
+        pRowidLe = apVal[i];
+        break;
+      default: assert( idxStr[iIdxStr-1]=='>' );
+        pRowidGe = apVal[i];
+        break;
+    }
+  }
+  bOrderByRank = ((idxNum & FTS5_BI_ORDER_RANK) ? 1 : 0);
+  pCsr->bDesc = bDesc = ((idxNum & FTS5_BI_ORDER_DESC) ? 1 : 0);
+
+  /* Set the cursor upper and lower rowid limits. Only some strategies
+  ** actually use them. This is ok, as the xBestIndex() method leaves the
+  ** sqlite3_index_constraint.omit flag clear for range constraints
+  ** on the rowid field.  */
+  if( pRowidEq ){
+    pRowidLe = pRowidGe = pRowidEq;
+  }
+  if( bDesc ){
+    pCsr->iFirstRowid = fts5GetRowidLimit(pRowidLe, LARGEST_INT64);
+    pCsr->iLastRowid = fts5GetRowidLimit(pRowidGe, SMALLEST_INT64);
+  }else{
+    pCsr->iLastRowid = fts5GetRowidLimit(pRowidLe, LARGEST_INT64);
+    pCsr->iFirstRowid = fts5GetRowidLimit(pRowidGe, SMALLEST_INT64);
+  }
+
+  rc = sqlite3Fts5IndexLoadConfig(pTab->p.pIndex);
+  if( rc!=SQLITE_OK ) goto filter_out;
+
+  if( pTab->pSortCsr ){
+    /* If pSortCsr is non-NULL, then this call is being made as part of
+    ** processing for a "... MATCH <expr> ORDER BY rank" query (ePlan is
+    ** set to FTS5_PLAN_SORTED_MATCH). pSortCsr is the cursor that will
+    ** return results to the user for this query. The current cursor
+    ** (pCursor) is used to execute the query issued by function
+    ** fts5CursorFirstSorted() above.  */
+    assert( pRowidEq==0 && pRowidLe==0 && pRowidGe==0 && pRank==0 );
+    assert( nVal==0 && bOrderByRank==0 && bDesc==0 );
+    assert( pCsr->iLastRowid==LARGEST_INT64 );
+    assert( pCsr->iFirstRowid==SMALLEST_INT64 );
+    if( pTab->pSortCsr->bDesc ){
+      pCsr->iLastRowid = pTab->pSortCsr->iFirstRowid;
+      pCsr->iFirstRowid = pTab->pSortCsr->iLastRowid;
+    }else{
+      pCsr->iLastRowid = pTab->pSortCsr->iLastRowid;
+      pCsr->iFirstRowid = pTab->pSortCsr->iFirstRowid;
+    }
+    pCsr->ePlan = FTS5_PLAN_SOURCE;
+    pCsr->pExpr = pTab->pSortCsr->pExpr;
+    rc = fts5CursorFirst(pTab, pCsr, bDesc);
+  }else if( pCsr->pExpr ){
+    assert( rc==SQLITE_OK );
+    rc = fts5CursorParseRank(pConfig, pCsr, pRank);
+    if( rc==SQLITE_OK ){
+      if( bOrderByRank ){
+        pCsr->ePlan = FTS5_PLAN_SORTED_MATCH;
+        rc = fts5CursorFirstSorted(pTab, pCsr, bDesc);
+      }else{
+        pCsr->ePlan = FTS5_PLAN_MATCH;
+        rc = fts5CursorFirst(pTab, pCsr, bDesc);
+      }
+    }
+  }else if( pConfig->zContent==0 ){
+    fts5SetVtabError(pTab,"%s: table does not support scanning",pConfig->zName);
+    rc = SQLITE_ERROR;
+  }else{
+    /* This is either a full-table scan (ePlan==FTS5_PLAN_SCAN) or a lookup
+    ** by rowid (ePlan==FTS5_PLAN_ROWID).  */
+    pCsr->ePlan = (pRowidEq ? FTS5_PLAN_ROWID : FTS5_PLAN_SCAN);
+    rc = sqlite3Fts5StorageStmt(
+        pTab->pStorage, fts5StmtType(pCsr), &pCsr->pStmt, &pTab->p.base.zErrMsg
+    );
+    if( rc==SQLITE_OK ){
+      if( pRowidEq!=0 ){
+        assert( pCsr->ePlan==FTS5_PLAN_ROWID );
+        sqlite3_bind_value(pCsr->pStmt, 1, pRowidEq);
+      }else{
+        sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iFirstRowid);
+        sqlite3_bind_int64(pCsr->pStmt, 2, pCsr->iLastRowid);
+      }
+      rc = fts5NextMethod(pCursor);
+    }
+  }
+
+ filter_out:
+  sqlite3Fts5ExprFree(pExpr);
+  pConfig->pzErrmsg = pzErrmsg;
+  pConfig->bPrefixInsttoken = bPrefixInsttoken;
+  return rc;
+}
+
+/*
+** This is the xEof method of the virtual table. SQLite calls this
+** routine to find out if it has reached the end of a result set.
+*/
+static int fts5EofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  return (CsrFlagTest(pCsr, FTS5CSR_EOF) ? 1 : 0);
+}
+
+/*
+** Return the rowid that the cursor currently points to.
+*/
+static i64 fts5CursorRowid(Fts5Cursor *pCsr){
+  assert( pCsr->ePlan==FTS5_PLAN_MATCH
+       || pCsr->ePlan==FTS5_PLAN_SORTED_MATCH
+       || pCsr->ePlan==FTS5_PLAN_SOURCE
+       || pCsr->ePlan==FTS5_PLAN_SCAN
+       || pCsr->ePlan==FTS5_PLAN_ROWID
+  );
+  if( pCsr->pSorter ){
+    return pCsr->pSorter->iRowid;
+  }else if( pCsr->ePlan>=FTS5_PLAN_SCAN ){
+    return sqlite3_column_int64(pCsr->pStmt, 0);
+  }else{
+    return sqlite3Fts5ExprRowid(pCsr->pExpr);
+  }
+}
+
+/*
+** This is the xRowid method. The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set. fts5
+** exposes %_content.rowid as the rowid for the virtual table. The
+** rowid should be written to *pRowid.
+*/
+static int fts5RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int ePlan = pCsr->ePlan;
+
+  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );
+  if( ePlan==FTS5_PLAN_SPECIAL ){
+    *pRowid = 0;
+  }else{
+    *pRowid = fts5CursorRowid(pCsr);
+  }
+
+  return SQLITE_OK;
+}
+
+
+/*
+** If the cursor requires seeking (bSeekRequired flag is set), seek it.
+** Return SQLITE_OK if no error occurs, or an SQLite error code otherwise.
+**
+** If argument bErrormsg is true and an error occurs, an error message may
+** be left in sqlite3_vtab.zErrMsg.
+*/
+static int fts5SeekCursor(Fts5Cursor *pCsr, int bErrormsg){
+  int rc = SQLITE_OK;
+
+  /* If the cursor does not yet have a statement handle, obtain one now. */
+  if( pCsr->pStmt==0 ){
+    Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+    int eStmt = fts5StmtType(pCsr);
+    rc = sqlite3Fts5StorageStmt(
+        pTab->pStorage, eStmt, &pCsr->pStmt, (bErrormsg?&pTab->p.base.zErrMsg:0)
+    );
+    assert( rc!=SQLITE_OK || pTab->p.base.zErrMsg==0 );
+    assert( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) );
+  }
+
+  if( rc==SQLITE_OK && CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) ){
+    Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+    assert( pCsr->pExpr );
+    sqlite3_reset(pCsr->pStmt);
+    sqlite3_bind_int64(pCsr->pStmt, 1, fts5CursorRowid(pCsr));
+    pTab->pConfig->bLock++;
+    rc = sqlite3_step(pCsr->pStmt);
+    pTab->pConfig->bLock--;
+    if( rc==SQLITE_ROW ){
+      rc = SQLITE_OK;
+      CsrFlagClear(pCsr, FTS5CSR_REQUIRE_CONTENT);
+    }else{
+      rc = sqlite3_reset(pCsr->pStmt);
+      if( rc==SQLITE_OK ){
+        rc = FTS5_CORRUPT;
+        fts5SetVtabError((Fts5FullTable*)pTab,
+            "fts5: missing row %lld from content table %s",
+            fts5CursorRowid(pCsr),
+            pTab->pConfig->zContent
+        );
+      }else if( pTab->pConfig->pzErrmsg ){
+        fts5SetVtabError((Fts5FullTable*)pTab,
+            "%s", sqlite3_errmsg(pTab->pConfig->db)
+        );
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is called to handle an FTS INSERT command. In other words,
+** an INSERT statement of the form:
+**
+**     INSERT INTO fts(fts) VALUES($pCmd)
+**     INSERT INTO fts(fts, rank) VALUES($pCmd, $pVal)
+**
+** Argument pVal is the value assigned to column "fts" by the INSERT
+** statement. This function returns SQLITE_OK if successful, or an SQLite
+** error code if an error occurs.
+**
+** The commands implemented by this function are documented in the "Special
+** INSERT Directives" section of the documentation. It should be updated if
+** more commands are added to this function.
+*/
+static int fts5SpecialInsert(
+  Fts5FullTable *pTab,            /* Fts5 table object */
+  const char *zCmd,               /* Text inserted into table-name column */
+  sqlite3_value *pVal             /* Value inserted into rank column */
+){
+  Fts5Config *pConfig = pTab->p.pConfig;
+  int rc = SQLITE_OK;
+  int bError = 0;
+  int bLoadConfig = 0;
+
+  if( 0==sqlite3_stricmp("delete-all", zCmd) ){
+    if( pConfig->eContent==FTS5_CONTENT_NORMAL ){
+      fts5SetVtabError(pTab,
+          "'delete-all' may only be used with a "
+          "contentless or external content fts5 table"
+      );
+      rc = SQLITE_ERROR;
+    }else{
+      rc = sqlite3Fts5StorageDeleteAll(pTab->pStorage);
+    }
+    bLoadConfig = 1;
+  }else if( 0==sqlite3_stricmp("rebuild", zCmd) ){
+    if( fts5IsContentless(pTab, 1) ){
+      fts5SetVtabError(pTab,
+          "'rebuild' may not be used with a contentless fts5 table"
+      );
+      rc = SQLITE_ERROR;
+    }else{
+      rc = sqlite3Fts5StorageRebuild(pTab->pStorage);
+    }
+    bLoadConfig = 1;
+  }else if( 0==sqlite3_stricmp("optimize", zCmd) ){
+    rc = sqlite3Fts5StorageOptimize(pTab->pStorage);
+  }else if( 0==sqlite3_stricmp("merge", zCmd) ){
+    int nMerge = sqlite3_value_int(pVal);
+    rc = sqlite3Fts5StorageMerge(pTab->pStorage, nMerge);
+  }else if( 0==sqlite3_stricmp("integrity-check", zCmd) ){
+    int iArg = sqlite3_value_int(pVal);
+    rc = sqlite3Fts5StorageIntegrity(pTab->pStorage, iArg);
+#ifdef SQLITE_DEBUG
+  }else if( 0==sqlite3_stricmp("prefix-index", zCmd) ){
+    pConfig->bPrefixIndex = sqlite3_value_int(pVal);
+#endif
+  }else if( 0==sqlite3_stricmp("flush", zCmd) ){
+    rc = sqlite3Fts5FlushToDisk(&pTab->p);
+  }else{
+    rc = sqlite3Fts5FlushToDisk(&pTab->p);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5IndexLoadConfig(pTab->p.pIndex);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5ConfigSetValue(pTab->p.pConfig, zCmd, pVal, &bError);
+    }
+    if( rc==SQLITE_OK ){
+      if( bError ){
+        rc = SQLITE_ERROR;
+      }else{
+        rc = sqlite3Fts5StorageConfigValue(pTab->pStorage, zCmd, pVal, 0);
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK && bLoadConfig ){
+    pTab->p.pConfig->iCookie--;
+    rc = sqlite3Fts5IndexLoadConfig(pTab->p.pIndex);
+  }
+
+  return rc;
+}
+
+static int fts5SpecialDelete(
+  Fts5FullTable *pTab,
+  sqlite3_value **apVal
+){
+  int rc = SQLITE_OK;
+  int eType1 = sqlite3_value_type(apVal[1]);
+  if( eType1==SQLITE_INTEGER ){
+    sqlite3_int64 iDel = sqlite3_value_int64(apVal[1]);
+    rc = sqlite3Fts5StorageDelete(pTab->pStorage, iDel, &apVal[2], 0);
+  }
+  return rc;
+}
+
+static void fts5StorageInsert(
+  int *pRc,
+  Fts5FullTable *pTab,
+  sqlite3_value **apVal,
+  i64 *piRowid
+){
+  int rc = *pRc;
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageContentInsert(pTab->pStorage, 0, apVal, piRowid);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageIndexInsert(pTab->pStorage, apVal, *piRowid);
+  }
+  *pRc = rc;
+}
+
+/*
+**
+** This function is called when the user attempts an UPDATE on a contentless
+** table. Parameter bRowidModified is true if the UPDATE statement modifies
+** the rowid value. Parameter apVal[] contains the new values for each user
+** defined column of the fts5 table. pConfig is the configuration object of the
+** table being updated (guaranteed to be contentless). The contentless_delete=1
+** and contentless_unindexed=1 options may or may not be set.
+**
+** This function returns SQLITE_OK if the UPDATE can go ahead, or an SQLite
+** error code if it cannot. In this case an error message is also loaded into
+** pConfig. Output parameter (*pbContent) is set to true if the caller should
+** update the %_content table only - not the FTS index or any other shadow
+** table. This occurs when an UPDATE modifies only UNINDEXED columns of the
+** table.
+**
+** An UPDATE may proceed if:
+**
+**   * The only columns modified are UNINDEXED columns, or
+**
+**   * The contentless_delete=1 option was specified and all of the indexed
+**     columns (not a subset) have been modified.
+*/
+static int fts5ContentlessUpdate(
+  Fts5Config *pConfig,
+  sqlite3_value **apVal,
+  int bRowidModified,
+  int *pbContent
+){
+  int ii;
+  int bSeenIndex = 0;             /* Have seen modified indexed column */
+  int bSeenIndexNC = 0;           /* Have seen unmodified indexed column */
+  int rc = SQLITE_OK;
+
+  for(ii=0; ii<pConfig->nCol; ii++){
+    if( pConfig->abUnindexed[ii]==0 ){
+      if( sqlite3_value_nochange(apVal[ii]) ){
+        bSeenIndexNC++;
+      }else{
+        bSeenIndex++;
+      }
+    }
+  }
+
+  if( bSeenIndex==0 && bRowidModified==0 ){
+    *pbContent = 1;
+  }else{
+    if( bSeenIndexNC || pConfig->bContentlessDelete==0 ){
+      rc = SQLITE_ERROR;
+      sqlite3Fts5ConfigErrmsg(pConfig,
+          (pConfig->bContentlessDelete ?
+          "%s a subset of columns on fts5 contentless-delete table: %s" :
+          "%s contentless fts5 table: %s")
+          , "cannot UPDATE", pConfig->zName
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is the implementation of the xUpdate callback used by
+** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
+** inserted, updated or deleted.
+**
+** A delete specifies a single argument - the rowid of the row to remove.
+**
+** Update and insert operations pass:
+**
+**   1. The "old" rowid, or NULL.
+**   2. The "new" rowid.
+**   3. Values for each of the nCol matchable columns.
+**   4. Values for the two hidden columns (<tablename> and "rank").
+*/
+static int fts5UpdateMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  Fts5Config *pConfig = pTab->p.pConfig;
+  int eType0;                     /* value_type() of apVal[0] */
+  int rc = SQLITE_OK;             /* Return code */
+
+  /* A transaction must be open when this is called. */
+  assert( pTab->ts.eState==1 || pTab->ts.eState==2 );
+
+  assert( pVtab->zErrMsg==0 );
+  assert( nArg==1 || nArg==(2+pConfig->nCol+2) );
+  assert( sqlite3_value_type(apVal[0])==SQLITE_INTEGER
+       || sqlite3_value_type(apVal[0])==SQLITE_NULL
+  );
+  assert( pTab->p.pConfig->pzErrmsg==0 );
+  if( pConfig->pgsz==0 ){
+    rc = sqlite3Fts5ConfigLoad(pTab->p.pConfig, pTab->p.pConfig->iCookie);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  pTab->p.pConfig->pzErrmsg = &pTab->p.base.zErrMsg;
+
+  /* Put any active cursors into REQUIRE_SEEK state. */
+  fts5TripCursors(pTab);
+
+  eType0 = sqlite3_value_type(apVal[0]);
+  if( eType0==SQLITE_NULL
+   && sqlite3_value_type(apVal[2+pConfig->nCol])!=SQLITE_NULL
+  ){
+    /* A "special" INSERT op. These are handled separately. */
+    const char *z = (const char*)sqlite3_value_text(apVal[2+pConfig->nCol]);
+    if( pConfig->eContent!=FTS5_CONTENT_NORMAL
+      && 0==sqlite3_stricmp("delete", z)
+    ){
+      if( pConfig->bContentlessDelete ){
+        fts5SetVtabError(pTab,
+            "'delete' may not be used with a contentless_delete=1 table"
+        );
+        rc = SQLITE_ERROR;
+      }else{
+        rc = fts5SpecialDelete(pTab, apVal);
+      }
+    }else{
+      rc = fts5SpecialInsert(pTab, z, apVal[2 + pConfig->nCol + 1]);
+    }
+  }else{
+    /* A regular INSERT, UPDATE or DELETE statement. The trick here is that
+    ** any conflict on the rowid value must be detected before any
+    ** modifications are made to the database file. There are 4 cases:
+    **
+    **   1) DELETE
+    **   2) UPDATE (rowid not modified)
+    **   3) UPDATE (rowid modified)
+    **   4) INSERT
+    **
+    ** Cases 3 and 4 may violate the rowid constraint.
+    */
+    int eConflict = SQLITE_ABORT;
+    if( pConfig->eContent==FTS5_CONTENT_NORMAL || pConfig->bContentlessDelete ){
+      eConflict = sqlite3_vtab_on_conflict(pConfig->db);
+    }
+
+    assert( eType0==SQLITE_INTEGER || eType0==SQLITE_NULL );
+    assert( nArg!=1 || eType0==SQLITE_INTEGER );
+
+    /* DELETE */
+    if( nArg==1 ){
+      /* It is only possible to DELETE from a contentless table if the
+      ** contentless_delete=1 flag is set. */
+      if( fts5IsContentless(pTab, 1) && pConfig->bContentlessDelete==0 ){
+        fts5SetVtabError(pTab,
+            "cannot DELETE from contentless fts5 table: %s", pConfig->zName
+        );
+        rc = SQLITE_ERROR;
+      }else{
+        i64 iDel = sqlite3_value_int64(apVal[0]);  /* Rowid to delete */
+        rc = sqlite3Fts5StorageDelete(pTab->pStorage, iDel, 0, 0);
+      }
+    }
+
+    /* INSERT or UPDATE */
+    else{
+      int eType1 = sqlite3_value_numeric_type(apVal[1]);
+
+      /* It is an error to write an fts5_locale() value to a table without
+      ** the locale=1 option. */
+      if( pConfig->bLocale==0 ){
+        int ii;
+        for(ii=0; ii<pConfig->nCol; ii++){
+          sqlite3_value *pVal = apVal[ii+2];
+          if( sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+            fts5SetVtabError(pTab, "fts5_locale() requires locale=1");
+            rc = SQLITE_MISMATCH;
+            goto update_out;
+          }
+        }
+      }
+
+      if( eType0!=SQLITE_INTEGER ){
+        /* An INSERT statement. If the conflict-mode is REPLACE, first remove
+        ** the current entry (if any). */
+        if( eConflict==SQLITE_REPLACE && eType1==SQLITE_INTEGER ){
+          i64 iNew = sqlite3_value_int64(apVal[1]);  /* Rowid to delete */
+          rc = sqlite3Fts5StorageDelete(pTab->pStorage, iNew, 0, 0);
+        }
+        fts5StorageInsert(&rc, pTab, apVal, pRowid);
+      }
+
+      /* UPDATE */
+      else{
+        Fts5Storage *pStorage = pTab->pStorage;
+        i64 iOld = sqlite3_value_int64(apVal[0]);  /* Old rowid */
+        i64 iNew = sqlite3_value_int64(apVal[1]);  /* New rowid */
+        int bContent = 0;         /* Content only update */
+
+        /* If this is a contentless table (including contentless_unindexed=1
+        ** tables), check if the UPDATE may proceed.  */
+        if( fts5IsContentless(pTab, 1) ){
+          rc = fts5ContentlessUpdate(pConfig, &apVal[2], iOld!=iNew, &bContent);
+          if( rc!=SQLITE_OK ) goto update_out;
+        }
+
+        if( eType1!=SQLITE_INTEGER ){
+          rc = SQLITE_MISMATCH;
+        }else if( iOld!=iNew ){
+          assert( bContent==0 );
+          if( eConflict==SQLITE_REPLACE ){
+            rc = sqlite3Fts5StorageDelete(pStorage, iOld, 0, 1);
+            if( rc==SQLITE_OK ){
+              rc = sqlite3Fts5StorageDelete(pStorage, iNew, 0, 0);
+            }
+            fts5StorageInsert(&rc, pTab, apVal, pRowid);
+          }else{
+            rc = sqlite3Fts5StorageFindDeleteRow(pStorage, iOld);
+            if( rc==SQLITE_OK ){
+              rc = sqlite3Fts5StorageContentInsert(pStorage, 0, apVal, pRowid);
+            }
+            if( rc==SQLITE_OK ){
+              rc = sqlite3Fts5StorageDelete(pStorage, iOld, 0, 0);
+            }
+            if( rc==SQLITE_OK ){
+              rc = sqlite3Fts5StorageIndexInsert(pStorage, apVal, *pRowid);
+            }
+          }
+        }else if( bContent ){
+          /* This occurs when an UPDATE on a contentless table affects *only*
+          ** UNINDEXED columns. This is a no-op for contentless_unindexed=0
+          ** tables, or a write to the %_content table only for =1 tables.  */
+          assert( fts5IsContentless(pTab, 1) );
+          rc = sqlite3Fts5StorageFindDeleteRow(pStorage, iOld);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5StorageContentInsert(pStorage, 1, apVal, pRowid);
+          }
+        }else{
+          rc = sqlite3Fts5StorageDelete(pStorage, iOld, 0, 1);
+          fts5StorageInsert(&rc, pTab, apVal, pRowid);
+        }
+        sqlite3Fts5StorageReleaseDeleteRow(pStorage);
+      }
+    }
+  }
+
+ update_out:
+  pTab->p.pConfig->pzErrmsg = 0;
+  return rc;
+}
+
+/*
+** Implementation of xSync() method.
+*/
+static int fts5SyncMethod(sqlite3_vtab *pVtab){
+  int rc;
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  fts5CheckTransactionState(pTab, FTS5_SYNC, 0);
+  pTab->p.pConfig->pzErrmsg = &pTab->p.base.zErrMsg;
+  rc = sqlite3Fts5FlushToDisk(&pTab->p);
+  pTab->p.pConfig->pzErrmsg = 0;
+  return rc;
+}
+
+/*
+** Implementation of xBegin() method.
+*/
+static int fts5BeginMethod(sqlite3_vtab *pVtab){
+  int rc = fts5NewTransaction((Fts5FullTable*)pVtab);
+  if( rc==SQLITE_OK ){
+    fts5CheckTransactionState((Fts5FullTable*)pVtab, FTS5_BEGIN, 0);
+  }
+  return rc;
+}
+
+/*
+** Implementation of xCommit() method. This is a no-op. The contents of
+** the pending-terms hash-table have already been flushed into the database
+** by fts5SyncMethod().
+*/
+static int fts5CommitMethod(sqlite3_vtab *pVtab){
+  UNUSED_PARAM(pVtab);  /* Call below is a no-op for NDEBUG builds */
+  fts5CheckTransactionState((Fts5FullTable*)pVtab, FTS5_COMMIT, 0);
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xRollback(). Discard the contents of the pending-terms
+** hash-table. Any changes made to the database are reverted by SQLite.
+*/
+static int fts5RollbackMethod(sqlite3_vtab *pVtab){
+  int rc;
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  fts5CheckTransactionState(pTab, FTS5_ROLLBACK, 0);
+  rc = sqlite3Fts5StorageRollback(pTab->pStorage);
+  pTab->p.pConfig->pgsz = 0;
+  return rc;
+}
+
+static int fts5CsrPoslist(Fts5Cursor*, int, const u8**, int*);
+
+static void *fts5ApiUserData(Fts5Context *pCtx){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return pCsr->pAux->pUserData;
+}
+
+static int fts5ApiColumnCount(Fts5Context *pCtx){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return ((Fts5Table*)(pCsr->base.pVtab))->pConfig->nCol;
+}
+
+static int fts5ApiColumnTotalSize(
+  Fts5Context *pCtx,
+  int iCol,
+  sqlite3_int64 *pnToken
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  return sqlite3Fts5StorageSize(pTab->pStorage, iCol, pnToken);
+}
+
+static int fts5ApiRowCount(Fts5Context *pCtx, i64 *pnRow){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  return sqlite3Fts5StorageRowCount(pTab->pStorage, pnRow);
+}
+
+/*
+** Implementation of xTokenize_v2() API.
+*/
+static int fts5ApiTokenize_v2(
+  Fts5Context *pCtx,
+  const char *pText, int nText,
+  const char *pLoc, int nLoc,
+  void *pUserData,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+  int rc = SQLITE_OK;
+
+  sqlite3Fts5SetLocale(pTab->pConfig, pLoc, nLoc);
+  rc = sqlite3Fts5Tokenize(pTab->pConfig,
+      FTS5_TOKENIZE_AUX, pText, nText, pUserData, xToken
+  );
+  sqlite3Fts5SetLocale(pTab->pConfig, 0, 0);
+
+  return rc;
+}
+
+/*
+** Implementation of xTokenize() API. This is just xTokenize_v2() with NULL/0
+** passed as the locale.
+*/
+static int fts5ApiTokenize(
+  Fts5Context *pCtx,
+  const char *pText, int nText,
+  void *pUserData,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  return fts5ApiTokenize_v2(pCtx, pText, nText, 0, 0, pUserData, xToken);
+}
+
+static int fts5ApiPhraseCount(Fts5Context *pCtx){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+}
+
+static int fts5ApiPhraseSize(Fts5Context *pCtx, int iPhrase){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return sqlite3Fts5ExprPhraseSize(pCsr->pExpr, iPhrase);
+}
+
+/*
+** Argument pStmt is an SQL statement of the type used by Fts5Cursor. This
+** function extracts the text value of column iCol of the current row.
+** Additionally, if there is an associated locale, it invokes
+** sqlite3Fts5SetLocale() to configure the tokenizer. In all cases the caller
+** should invoke sqlite3Fts5ClearLocale() to clear the locale at some point
+** after this function returns.
+**
+** If successful, (*ppText) is set to point to a buffer containing the text
+** value as utf-8 and SQLITE_OK returned. (*pnText) is set to the size of that
+** buffer in bytes. It is not guaranteed to be nul-terminated. If an error
+** occurs, an SQLite error code is returned. The final values of the two
+** output parameters are undefined in this case.
+*/
+static int fts5TextFromStmt(
+  Fts5Config *pConfig,
+  sqlite3_stmt *pStmt,
+  int iCol,
+  const char **ppText,
+  int *pnText
+){
+  sqlite3_value *pVal = sqlite3_column_value(pStmt, iCol+1);
+  const char *pLoc = 0;
+  int nLoc = 0;
+  int rc = SQLITE_OK;
+
+  if( pConfig->bLocale
+   && pConfig->eContent==FTS5_CONTENT_EXTERNAL
+   && sqlite3Fts5IsLocaleValue(pConfig, pVal)
+  ){
+    rc = sqlite3Fts5DecodeLocaleValue(pVal, ppText, pnText, &pLoc, &nLoc);
+  }else{
+    *ppText = (const char*)sqlite3_value_text(pVal);
+    *pnText = sqlite3_value_bytes(pVal);
+    if( pConfig->bLocale && pConfig->eContent==FTS5_CONTENT_NORMAL ){
+      pLoc = (const char*)sqlite3_column_text(pStmt, iCol+1+pConfig->nCol);
+      nLoc = sqlite3_column_bytes(pStmt, iCol+1+pConfig->nCol);
+    }
+  }
+  sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+  return rc;
+}
+
+static int fts5ApiColumnText(
+  Fts5Context *pCtx,
+  int iCol,
+  const char **pz,
+  int *pn
+){
+  int rc = SQLITE_OK;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+
+  assert( pCsr->ePlan!=FTS5_PLAN_SPECIAL );
+  if( iCol<0 || iCol>=pTab->pConfig->nCol ){
+    rc = SQLITE_RANGE;
+  }else if( fts5IsContentless((Fts5FullTable*)(pCsr->base.pVtab), 0) ){
+    *pz = 0;
+    *pn = 0;
+  }else{
+    rc = fts5SeekCursor(pCsr, 0);
+    if( rc==SQLITE_OK ){
+      rc = fts5TextFromStmt(pTab->pConfig, pCsr->pStmt, iCol, pz, pn);
+      sqlite3Fts5ClearLocale(pTab->pConfig);
+    }
+  }
+  return rc;
+}
+
+/*
+** This is called by various API functions - xInst, xPhraseFirst,
+** xPhraseFirstColumn etc. - to obtain the position list for phrase iPhrase
+** of the current row. This function works for both detail=full tables (in
+** which case the position-list was read from the fts index) or for other
+** detail= modes if the row content is available.
+*/
+static int fts5CsrPoslist(
+  Fts5Cursor *pCsr,               /* Fts5 cursor object */
+  int iPhrase,                    /* Phrase to find position list for */
+  const u8 **pa,                  /* OUT: Pointer to position list buffer */
+  int *pn                         /* OUT: Size of (*pa) in bytes */
+){
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+  int rc = SQLITE_OK;
+  int bLive = (pCsr->pSorter==0);
+
+  if( iPhrase<0 || iPhrase>=sqlite3Fts5ExprPhraseCount(pCsr->pExpr) ){
+    rc = SQLITE_RANGE;
+  }else if( pConfig->eDetail!=FTS5_DETAIL_FULL
+         && fts5IsContentless((Fts5FullTable*)pCsr->base.pVtab, 1)
+  ){
+    *pa = 0;
+    *pn = 0;
+    return SQLITE_OK;
+  }else if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_POSLIST) ){
+    if( pConfig->eDetail!=FTS5_DETAIL_FULL ){
+      Fts5PoslistPopulator *aPopulator;
+      int i;
+
+      aPopulator = sqlite3Fts5ExprClearPoslists(pCsr->pExpr, bLive);
+      if( aPopulator==0 ) rc = SQLITE_NOMEM;
+      if( rc==SQLITE_OK ){
+        rc = fts5SeekCursor(pCsr, 0);
+      }
+      for(i=0; i<pConfig->nCol && rc==SQLITE_OK; i++){
+        const char *z = 0;
+        int n = 0;
+        rc = fts5TextFromStmt(pConfig, pCsr->pStmt, i, &z, &n);
+        if( rc==SQLITE_OK ){
+          rc = sqlite3Fts5ExprPopulatePoslists(
+              pConfig, pCsr->pExpr, aPopulator, i, z, n
+          );
+        }
+        sqlite3Fts5ClearLocale(pConfig);
+      }
+      sqlite3_free(aPopulator);
+
+      if( pCsr->pSorter ){
+        sqlite3Fts5ExprCheckPoslists(pCsr->pExpr, pCsr->pSorter->iRowid);
+      }
+    }
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_POSLIST);
+  }
+
+  if( rc==SQLITE_OK ){
+    if( pCsr->pSorter && pConfig->eDetail==FTS5_DETAIL_FULL ){
+      Fts5Sorter *pSorter = pCsr->pSorter;
+      int i1 = (iPhrase==0 ? 0 : pSorter->aIdx[iPhrase-1]);
+      *pn = pSorter->aIdx[iPhrase] - i1;
+      *pa = &pSorter->aPoslist[i1];
+    }else{
+      *pn = sqlite3Fts5ExprPoslist(pCsr->pExpr, iPhrase, pa);
+    }
+  }else{
+    *pa = 0;
+    *pn = 0;
+  }
+
+  return rc;
+}
+
+/*
+** Ensure that the Fts5Cursor.nInstCount and aInst[] variables are populated
+** correctly for the current view. Return SQLITE_OK if successful, or an
+** SQLite error code otherwise.
+*/
+static int fts5CacheInstArray(Fts5Cursor *pCsr){
+  int rc = SQLITE_OK;
+  Fts5PoslistReader *aIter;       /* One iterator for each phrase */
+  int nIter;                      /* Number of iterators/phrases */
+  int nCol = ((Fts5Table*)pCsr->base.pVtab)->pConfig->nCol;
+
+  nIter = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+  if( pCsr->aInstIter==0 ){
+    sqlite3_int64 nByte = sizeof(Fts5PoslistReader) * nIter;
+    pCsr->aInstIter = (Fts5PoslistReader*)sqlite3Fts5MallocZero(&rc, nByte);
+  }
+  aIter = pCsr->aInstIter;
+
+  if( aIter ){
+    int nInst = 0;                /* Number instances seen so far */
+    int i;
+
+    /* Initialize all iterators */
+    for(i=0; i<nIter && rc==SQLITE_OK; i++){
+      const u8 *a;
+      int n;
+      rc = fts5CsrPoslist(pCsr, i, &a, &n);
+      if( rc==SQLITE_OK ){
+        sqlite3Fts5PoslistReaderInit(a, n, &aIter[i]);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      while( 1 ){
+        int *aInst;
+        int iBest = -1;
+        for(i=0; i<nIter; i++){
+          if( (aIter[i].bEof==0)
+              && (iBest<0 || aIter[i].iPos<aIter[iBest].iPos)
+            ){
+            iBest = i;
+          }
+        }
+        if( iBest<0 ) break;
+
+        nInst++;
+        if( nInst>=pCsr->nInstAlloc ){
+          int nNewSize = pCsr->nInstAlloc ? pCsr->nInstAlloc*2 : 32;
+          aInst = (int*)sqlite3_realloc64(
+              pCsr->aInst, nNewSize*sizeof(int)*3
+              );
+          if( aInst ){
+            pCsr->aInst = aInst;
+            pCsr->nInstAlloc = nNewSize;
+          }else{
+            nInst--;
+            rc = SQLITE_NOMEM;
+            break;
+          }
+        }
+
+        aInst = &pCsr->aInst[3 * (nInst-1)];
+        aInst[0] = iBest;
+        aInst[1] = FTS5_POS2COLUMN(aIter[iBest].iPos);
+        aInst[2] = FTS5_POS2OFFSET(aIter[iBest].iPos);
+        assert( aInst[1]>=0 );
+        if( aInst[1]>=nCol ){
+          rc = FTS5_CORRUPT;
+          break;
+        }
+        sqlite3Fts5PoslistReaderNext(&aIter[iBest]);
+      }
+    }
+
+    pCsr->nInstCount = nInst;
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_INST);
+  }
+  return rc;
+}
+
+static int fts5ApiInstCount(Fts5Context *pCtx, int *pnInst){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int rc = SQLITE_OK;
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_INST)==0
+   || SQLITE_OK==(rc = fts5CacheInstArray(pCsr)) ){
+    *pnInst = pCsr->nInstCount;
+  }
+  return rc;
+}
+
+static int fts5ApiInst(
+  Fts5Context *pCtx,
+  int iIdx,
+  int *piPhrase,
+  int *piCol,
+  int *piOff
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int rc = SQLITE_OK;
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_INST)==0
+   || SQLITE_OK==(rc = fts5CacheInstArray(pCsr))
+  ){
+    if( iIdx<0 || iIdx>=pCsr->nInstCount ){
+      rc = SQLITE_RANGE;
+    }else{
+      *piPhrase = pCsr->aInst[iIdx*3];
+      *piCol = pCsr->aInst[iIdx*3 + 1];
+      *piOff = pCsr->aInst[iIdx*3 + 2];
+    }
+  }
+  return rc;
+}
+
+static sqlite3_int64 fts5ApiRowid(Fts5Context *pCtx){
+  return fts5CursorRowid((Fts5Cursor*)pCtx);
+}
+
+static int fts5ColumnSizeCb(
+  void *pContext,                 /* Pointer to int */
+  int tflags,
+  const char *pUnused,            /* Buffer containing token */
+  int nUnused,                    /* Size of token in bytes */
+  int iUnused1,                   /* Start offset of token */
+  int iUnused2                    /* End offset of token */
+){
+  int *pCnt = (int*)pContext;
+  UNUSED_PARAM2(pUnused, nUnused);
+  UNUSED_PARAM2(iUnused1, iUnused2);
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 ){
+    (*pCnt)++;
+  }
+  return SQLITE_OK;
+}
+
+static int fts5ApiColumnSize(Fts5Context *pCtx, int iCol, int *pnToken){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  Fts5Config *pConfig = pTab->p.pConfig;
+  int rc = SQLITE_OK;
+
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_DOCSIZE) ){
+    if( pConfig->bColumnsize ){
+      i64 iRowid = fts5CursorRowid(pCsr);
+      rc = sqlite3Fts5StorageDocsize(pTab->pStorage, iRowid, pCsr->aColumnSize);
+    }else if( !pConfig->zContent || pConfig->eContent==FTS5_CONTENT_UNINDEXED ){
+      int i;
+      for(i=0; i<pConfig->nCol; i++){
+        if( pConfig->abUnindexed[i]==0 ){
+          pCsr->aColumnSize[i] = -1;
+        }
+      }
+    }else{
+      int i;
+      rc = fts5SeekCursor(pCsr, 0);
+      for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
+        if( pConfig->abUnindexed[i]==0 ){
+          const char *z = 0;
+          int n = 0;
+          pCsr->aColumnSize[i] = 0;
+          rc = fts5TextFromStmt(pConfig, pCsr->pStmt, i, &z, &n);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5Tokenize(pConfig, FTS5_TOKENIZE_AUX,
+                z, n, (void*)&pCsr->aColumnSize[i], fts5ColumnSizeCb
+            );
+          }
+          sqlite3Fts5ClearLocale(pConfig);
+        }
+      }
+    }
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_DOCSIZE);
+  }
+  if( iCol<0 ){
+    int i;
+    *pnToken = 0;
+    for(i=0; i<pConfig->nCol; i++){
+      *pnToken += pCsr->aColumnSize[i];
+    }
+  }else if( iCol<pConfig->nCol ){
+    *pnToken = pCsr->aColumnSize[iCol];
+  }else{
+    *pnToken = 0;
+    rc = SQLITE_RANGE;
+  }
+  return rc;
+}
+
+/*
+** Implementation of the xSetAuxdata() method.
+*/
+static int fts5ApiSetAuxdata(
+  Fts5Context *pCtx,              /* Fts5 context */
+  void *pPtr,                     /* Pointer to save as auxdata */
+  void(*xDelete)(void*)           /* Destructor for pPtr (or NULL) */
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Auxdata *pData;
+
+  /* Search through the cursors list of Fts5Auxdata objects for one that
+  ** corresponds to the currently executing auxiliary function.  */
+  for(pData=pCsr->pAuxdata; pData; pData=pData->pNext){
+    if( pData->pAux==pCsr->pAux ) break;
+  }
+
+  if( pData ){
+    if( pData->xDelete ){
+      pData->xDelete(pData->pPtr);
+    }
+  }else{
+    int rc = SQLITE_OK;
+    pData = (Fts5Auxdata*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Auxdata));
+    if( pData==0 ){
+      if( xDelete ) xDelete(pPtr);
+      return rc;
+    }
+    pData->pAux = pCsr->pAux;
+    pData->pNext = pCsr->pAuxdata;
+    pCsr->pAuxdata = pData;
+  }
+
+  pData->xDelete = xDelete;
+  pData->pPtr = pPtr;
+  return SQLITE_OK;
+}
+
+static void *fts5ApiGetAuxdata(Fts5Context *pCtx, int bClear){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Auxdata *pData;
+  void *pRet = 0;
+
+  for(pData=pCsr->pAuxdata; pData; pData=pData->pNext){
+    if( pData->pAux==pCsr->pAux ) break;
+  }
+
+  if( pData ){
+    pRet = pData->pPtr;
+    if( bClear ){
+      pData->pPtr = 0;
+      pData->xDelete = 0;
+    }
+  }
+
+  return pRet;
+}
+
+static void fts5ApiPhraseNext(
+  Fts5Context *pCtx,
+  Fts5PhraseIter *pIter,
+  int *piCol, int *piOff
+){
+  if( pIter->a>=pIter->b ){
+    *piCol = -1;
+    *piOff = -1;
+  }else{
+    int iVal;
+    pIter->a += fts5GetVarint32(pIter->a, iVal);
+    if( iVal==1 ){
+      /* Avoid returning a (*piCol) value that is too large for the table,
+      ** even if the position-list is corrupt. The caller might not be
+      ** expecting it.  */
+      int nCol = ((Fts5Table*)(((Fts5Cursor*)pCtx)->base.pVtab))->pConfig->nCol;
+      pIter->a += fts5GetVarint32(pIter->a, iVal);
+      *piCol = (iVal>=nCol ? nCol-1 : iVal);
+      *piOff = 0;
+      pIter->a += fts5GetVarint32(pIter->a, iVal);
+    }
+    *piOff += (iVal-2);
+  }
+}
+
+static int fts5ApiPhraseFirst(
+  Fts5Context *pCtx,
+  int iPhrase,
+  Fts5PhraseIter *pIter,
+  int *piCol, int *piOff
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int n;
+  int rc = fts5CsrPoslist(pCsr, iPhrase, &pIter->a, &n);
+  if( rc==SQLITE_OK ){
+    assert( pIter->a || n==0 );
+    pIter->b = (pIter->a ? &pIter->a[n] : 0);
+    *piCol = 0;
+    *piOff = 0;
+    fts5ApiPhraseNext(pCtx, pIter, piCol, piOff);
+  }
+  return rc;
+}
+
+static void fts5ApiPhraseNextColumn(
+  Fts5Context *pCtx,
+  Fts5PhraseIter *pIter,
+  int *piCol
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+
+  if( pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+    if( pIter->a>=pIter->b ){
+      *piCol = -1;
+    }else{
+      int iIncr;
+      pIter->a += fts5GetVarint32(&pIter->a[0], iIncr);
+      *piCol += (iIncr-2);
+    }
+  }else{
+    while( 1 ){
+      int dummy;
+      if( pIter->a>=pIter->b ){
+        *piCol = -1;
+        return;
+      }
+      if( pIter->a[0]==0x01 ) break;
+      pIter->a += fts5GetVarint32(pIter->a, dummy);
+    }
+    pIter->a += 1 + fts5GetVarint32(&pIter->a[1], *piCol);
+  }
+}
+
+static int fts5ApiPhraseFirstColumn(
+  Fts5Context *pCtx,
+  int iPhrase,
+  Fts5PhraseIter *pIter,
+  int *piCol
+){
+  int rc = SQLITE_OK;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+
+  if( pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+    Fts5Sorter *pSorter = pCsr->pSorter;
+    int n;
+    if( pSorter ){
+      int i1 = (iPhrase==0 ? 0 : pSorter->aIdx[iPhrase-1]);
+      n = pSorter->aIdx[iPhrase] - i1;
+      pIter->a = &pSorter->aPoslist[i1];
+    }else{
+      rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, iPhrase, &pIter->a, &n);
+    }
+    if( rc==SQLITE_OK ){
+      assert( pIter->a || n==0 );
+      pIter->b = (pIter->a ? &pIter->a[n] : 0);
+      *piCol = 0;
+      fts5ApiPhraseNextColumn(pCtx, pIter, piCol);
+    }
+  }else{
+    int n;
+    rc = fts5CsrPoslist(pCsr, iPhrase, &pIter->a, &n);
+    if( rc==SQLITE_OK ){
+      assert( pIter->a || n==0 );
+      pIter->b = (pIter->a ? &pIter->a[n] : 0);
+      if( n<=0 ){
+        *piCol = -1;
+      }else if( pIter->a[0]==0x01 ){
+        pIter->a += 1 + fts5GetVarint32(&pIter->a[1], *piCol);
+      }else{
+        *piCol = 0;
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** xQueryToken() API implemenetation.
+*/
+static int fts5ApiQueryToken(
+  Fts5Context* pCtx,
+  int iPhrase,
+  int iToken,
+  const char **ppOut,
+  int *pnOut
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return sqlite3Fts5ExprQueryToken(pCsr->pExpr, iPhrase, iToken, ppOut, pnOut);
+}
+
+/*
+** xInstToken() API implemenetation.
+*/
+static int fts5ApiInstToken(
+  Fts5Context *pCtx,
+  int iIdx,
+  int iToken,
+  const char **ppOut, int *pnOut
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int rc = SQLITE_OK;
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_INST)==0
+   || SQLITE_OK==(rc = fts5CacheInstArray(pCsr))
+  ){
+    if( iIdx<0 || iIdx>=pCsr->nInstCount ){
+      rc = SQLITE_RANGE;
+    }else{
+      int iPhrase = pCsr->aInst[iIdx*3];
+      int iCol = pCsr->aInst[iIdx*3 + 1];
+      int iOff = pCsr->aInst[iIdx*3 + 2];
+      i64 iRowid = fts5CursorRowid(pCsr);
+      rc = sqlite3Fts5ExprInstToken(
+          pCsr->pExpr, iRowid, iPhrase, iCol, iOff, iToken, ppOut, pnOut
+      );
+    }
+  }
+  return rc;
+}
+
+
+static int fts5ApiQueryPhrase(Fts5Context*, int, void*,
+    int(*)(const Fts5ExtensionApi*, Fts5Context*, void*)
+);
+
+/*
+** The xColumnLocale() API.
+*/
+static int fts5ApiColumnLocale(
+  Fts5Context *pCtx,
+  int iCol,
+  const char **pzLocale,
+  int *pnLocale
+){
+  int rc = SQLITE_OK;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+
+  *pzLocale = 0;
+  *pnLocale = 0;
+
+  assert( pCsr->ePlan!=FTS5_PLAN_SPECIAL );
+  if( iCol<0 || iCol>=pConfig->nCol ){
+    rc = SQLITE_RANGE;
+  }else if(
+      pConfig->abUnindexed[iCol]==0
+   && 0==fts5IsContentless((Fts5FullTable*)pCsr->base.pVtab, 1)
+   && pConfig->bLocale
+  ){
+    rc = fts5SeekCursor(pCsr, 0);
+    if( rc==SQLITE_OK ){
+      const char *zDummy = 0;
+      int nDummy = 0;
+      rc = fts5TextFromStmt(pConfig, pCsr->pStmt, iCol, &zDummy, &nDummy);
+      if( rc==SQLITE_OK ){
+        *pzLocale = pConfig->t.pLocale;
+        *pnLocale = pConfig->t.nLocale;
+      }
+      sqlite3Fts5ClearLocale(pConfig);
+    }
+  }
+
+  return rc;
+}
+
+static const Fts5ExtensionApi sFts5Api = {
+  4,                            /* iVersion */
+  fts5ApiUserData,
+  fts5ApiColumnCount,
+  fts5ApiRowCount,
+  fts5ApiColumnTotalSize,
+  fts5ApiTokenize,
+  fts5ApiPhraseCount,
+  fts5ApiPhraseSize,
+  fts5ApiInstCount,
+  fts5ApiInst,
+  fts5ApiRowid,
+  fts5ApiColumnText,
+  fts5ApiColumnSize,
+  fts5ApiQueryPhrase,
+  fts5ApiSetAuxdata,
+  fts5ApiGetAuxdata,
+  fts5ApiPhraseFirst,
+  fts5ApiPhraseNext,
+  fts5ApiPhraseFirstColumn,
+  fts5ApiPhraseNextColumn,
+  fts5ApiQueryToken,
+  fts5ApiInstToken,
+  fts5ApiColumnLocale,
+  fts5ApiTokenize_v2
+};
+
+/*
+** Implementation of API function xQueryPhrase().
+*/
+static int fts5ApiQueryPhrase(
+  Fts5Context *pCtx,
+  int iPhrase,
+  void *pUserData,
+  int(*xCallback)(const Fts5ExtensionApi*, Fts5Context*, void*)
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  int rc;
+  Fts5Cursor *pNew = 0;
+
+  rc = fts5OpenMethod(pCsr->base.pVtab, (sqlite3_vtab_cursor**)&pNew);
+  if( rc==SQLITE_OK ){
+    pNew->ePlan = FTS5_PLAN_MATCH;
+    pNew->iFirstRowid = SMALLEST_INT64;
+    pNew->iLastRowid = LARGEST_INT64;
+    pNew->base.pVtab = (sqlite3_vtab*)pTab;
+    rc = sqlite3Fts5ExprClonePhrase(pCsr->pExpr, iPhrase, &pNew->pExpr);
+  }
+
+  if( rc==SQLITE_OK ){
+    for(rc = fts5CursorFirst(pTab, pNew, 0);
+        rc==SQLITE_OK && CsrFlagTest(pNew, FTS5CSR_EOF)==0;
+        rc = fts5NextMethod((sqlite3_vtab_cursor*)pNew)
+    ){
+      rc = xCallback(&sFts5Api, (Fts5Context*)pNew, pUserData);
+      if( rc!=SQLITE_OK ){
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+        break;
+      }
+    }
+  }
+
+  fts5CloseMethod((sqlite3_vtab_cursor*)pNew);
+  return rc;
+}
+
+static void fts5ApiInvoke(
+  Fts5Auxiliary *pAux,
+  Fts5Cursor *pCsr,
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( pCsr->pAux==0 );
+  assert( pCsr->ePlan!=FTS5_PLAN_SPECIAL );
+  pCsr->pAux = pAux;
+  pAux->xFunc(&sFts5Api, (Fts5Context*)pCsr, context, argc, argv);
+  pCsr->pAux = 0;
+}
+
+static Fts5Cursor *fts5CursorFromCsrid(Fts5Global *pGlobal, i64 iCsrId){
+  Fts5Cursor *pCsr;
+  for(pCsr=pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
+    if( pCsr->iCsrId==iCsrId ) break;
+  }
+  return pCsr;
+}
+
+/*
+** Parameter zFmt is a printf() style formatting string. This function
+** formats it using the trailing arguments and returns the result as
+** an error message to the context passed as the first argument.
+*/
+static void fts5ResultError(sqlite3_context *pCtx, const char *zFmt, ...){
+  char *zErr = 0;
+  va_list ap;
+  va_start(ap, zFmt);
+  zErr = sqlite3_vmprintf(zFmt, ap);
+  sqlite3_result_error(pCtx, zErr, -1);
+  sqlite3_free(zErr);
+  va_end(ap);
+}
+
+static void fts5ApiCallback(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+
+  Fts5Auxiliary *pAux;
+  Fts5Cursor *pCsr;
+  i64 iCsrId;
+
+  assert( argc>=1 );
+  pAux = (Fts5Auxiliary*)sqlite3_user_data(context);
+  iCsrId = sqlite3_value_int64(argv[0]);
+
+  pCsr = fts5CursorFromCsrid(pAux->pGlobal, iCsrId);
+  if( pCsr==0 || (pCsr->ePlan==0 || pCsr->ePlan==FTS5_PLAN_SPECIAL) ){
+    fts5ResultError(context, "no such cursor: %lld", iCsrId);
+  }else{
+    sqlite3_vtab *pTab = pCsr->base.pVtab;
+    fts5ApiInvoke(pAux, pCsr, context, argc-1, &argv[1]);
+    sqlite3_free(pTab->zErrMsg);
+    pTab->zErrMsg = 0;
+  }
+}
+
+
+/*
+** Given cursor id iId, return a pointer to the corresponding Fts5Table
+** object. Or NULL If the cursor id does not exist.
+*/
+static Fts5Table *sqlite3Fts5TableFromCsrid(
+  Fts5Global *pGlobal,            /* FTS5 global context for db handle */
+  i64 iCsrId                      /* Id of cursor to find */
+){
+  Fts5Cursor *pCsr;
+  pCsr = fts5CursorFromCsrid(pGlobal, iCsrId);
+  if( pCsr ){
+    return (Fts5Table*)pCsr->base.pVtab;
+  }
+  return 0;
+}
+
+/*
+** Return a "position-list blob" corresponding to the current position of
+** cursor pCsr via sqlite3_result_blob(). A position-list blob contains
+** the current position-list for each phrase in the query associated with
+** cursor pCsr.
+**
+** A position-list blob begins with (nPhrase-1) varints, where nPhrase is
+** the number of phrases in the query. Following the varints are the
+** concatenated position lists for each phrase, in order.
+**
+** The first varint (if it exists) contains the size of the position list
+** for phrase 0. The second (same disclaimer) contains the size of position
+** list 1. And so on. There is no size field for the final position list,
+** as it can be derived from the total size of the blob.
+*/
+static int fts5PoslistBlob(sqlite3_context *pCtx, Fts5Cursor *pCsr){
+  int i;
+  int rc = SQLITE_OK;
+  int nPhrase = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+  Fts5Buffer val;
+
+  memset(&val, 0, sizeof(Fts5Buffer));
+  switch( ((Fts5Table*)(pCsr->base.pVtab))->pConfig->eDetail ){
+    case FTS5_DETAIL_FULL:
+
+      /* Append the varints */
+      for(i=0; i<(nPhrase-1); i++){
+        const u8 *dummy;
+        int nByte = sqlite3Fts5ExprPoslist(pCsr->pExpr, i, &dummy);
+        sqlite3Fts5BufferAppendVarint(&rc, &val, nByte);
+      }
+
+      /* Append the position lists */
+      for(i=0; i<nPhrase; i++){
+        const u8 *pPoslist;
+        int nPoslist;
+        nPoslist = sqlite3Fts5ExprPoslist(pCsr->pExpr, i, &pPoslist);
+        sqlite3Fts5BufferAppendBlob(&rc, &val, nPoslist, pPoslist);
+      }
+      break;
+
+    case FTS5_DETAIL_COLUMNS:
+
+      /* Append the varints */
+      for(i=0; rc==SQLITE_OK && i<(nPhrase-1); i++){
+        const u8 *dummy;
+        int nByte;
+        rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, i, &dummy, &nByte);
+        sqlite3Fts5BufferAppendVarint(&rc, &val, nByte);
+      }
+
+      /* Append the position lists */
+      for(i=0; rc==SQLITE_OK && i<nPhrase; i++){
+        const u8 *pPoslist;
+        int nPoslist;
+        rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, i, &pPoslist, &nPoslist);
+        sqlite3Fts5BufferAppendBlob(&rc, &val, nPoslist, pPoslist);
+      }
+      break;
+
+    default:
+      break;
+  }
+
+  sqlite3_result_blob(pCtx, val.p, val.n, sqlite3_free);
+  return rc;
+}
+
+/*
+** This is the xColumn method, called by SQLite to request a value from
+** the row that the supplied cursor currently points to.
+*/
+static int fts5ColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCursor->pVtab);
+  Fts5Config *pConfig = pTab->p.pConfig;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int rc = SQLITE_OK;
+
+  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );
+
+  if( pCsr->ePlan==FTS5_PLAN_SPECIAL ){
+    if( iCol==pConfig->nCol ){
+      sqlite3_result_int64(pCtx, pCsr->iSpecial);
+    }
+  }else
+
+  if( iCol==pConfig->nCol ){
+    /* User is requesting the value of the special column with the same name
+    ** as the table. Return the cursor integer id number. This value is only
+    ** useful in that it may be passed as the first argument to an FTS5
+    ** auxiliary function.  */
+    sqlite3_result_int64(pCtx, pCsr->iCsrId);
+  }else if( iCol==pConfig->nCol+1 ){
+    /* The value of the "rank" column. */
+
+    if( pCsr->ePlan==FTS5_PLAN_SOURCE ){
+      fts5PoslistBlob(pCtx, pCsr);
+    }else if(
+        pCsr->ePlan==FTS5_PLAN_MATCH
+     || pCsr->ePlan==FTS5_PLAN_SORTED_MATCH
+    ){
+      if( pCsr->pRank || SQLITE_OK==(rc = fts5FindRankFunction(pCsr)) ){
+        fts5ApiInvoke(pCsr->pRank, pCsr, pCtx, pCsr->nRankArg, pCsr->apRankArg);
+      }
+    }
+  }else{
+    if( !sqlite3_vtab_nochange(pCtx) && pConfig->eContent!=FTS5_CONTENT_NONE ){
+      pConfig->pzErrmsg = &pTab->p.base.zErrMsg;
+      rc = fts5SeekCursor(pCsr, 1);
+      if( rc==SQLITE_OK ){
+        sqlite3_value *pVal = sqlite3_column_value(pCsr->pStmt, iCol+1);
+        if( pConfig->bLocale
+         && pConfig->eContent==FTS5_CONTENT_EXTERNAL
+         && sqlite3Fts5IsLocaleValue(pConfig, pVal)
+        ){
+          const char *z = 0;
+          int n = 0;
+          rc = fts5TextFromStmt(pConfig, pCsr->pStmt, iCol, &z, &n);
+          if( rc==SQLITE_OK ){
+            sqlite3_result_text(pCtx, z, n, SQLITE_TRANSIENT);
+          }
+          sqlite3Fts5ClearLocale(pConfig);
+        }else{
+          sqlite3_result_value(pCtx, pVal);
+        }
+      }
+
+      pConfig->pzErrmsg = 0;
+    }
+  }
+
+  return rc;
+}
+
+
+/*
+** This routine implements the xFindFunction method for the FTS3
+** virtual table.
+*/
+static int fts5FindFunctionMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nUnused,                    /* Number of SQL function arguments */
+  const char *zName,              /* Name of SQL function */
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
+  void **ppArg                    /* OUT: User data for *pxFunc */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  Fts5Auxiliary *pAux;
+
+  UNUSED_PARAM(nUnused);
+  pAux = fts5FindAuxiliary(pTab, zName);
+  if( pAux ){
+    *pxFunc = fts5ApiCallback;
+    *ppArg = (void*)pAux;
+    return 1;
+  }
+
+  /* No function of the specified name was found. Return 0. */
+  return 0;
+}
+
+/*
+** Implementation of FTS5 xRename method. Rename an fts5 table.
+*/
+static int fts5RenameMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  const char *zName               /* New name of table */
+){
+  int rc;
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  rc = sqlite3Fts5StorageRename(pTab->pStorage, zName);
+  return rc;
+}
+
+static int sqlite3Fts5FlushToDisk(Fts5Table *pTab){
+  fts5TripCursors((Fts5FullTable*)pTab);
+  return sqlite3Fts5StorageSync(((Fts5FullTable*)pTab)->pStorage);
+}
+
+/*
+** The xSavepoint() method.
+**
+** Flush the contents of the pending-terms table to disk.
+*/
+static int fts5SavepointMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  int rc = SQLITE_OK;
+
+  fts5CheckTransactionState(pTab, FTS5_SAVEPOINT, iSavepoint);
+  rc = sqlite3Fts5FlushToDisk((Fts5Table*)pVtab);
+  if( rc==SQLITE_OK ){
+    pTab->iSavepoint = iSavepoint+1;
+  }
+  return rc;
+}
+
+/*
+** The xRelease() method.
+**
+** This is a no-op.
+*/
+static int fts5ReleaseMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  int rc = SQLITE_OK;
+  fts5CheckTransactionState(pTab, FTS5_RELEASE, iSavepoint);
+  if( (iSavepoint+1)<pTab->iSavepoint ){
+    rc = sqlite3Fts5FlushToDisk(&pTab->p);
+    if( rc==SQLITE_OK ){
+      pTab->iSavepoint = iSavepoint;
+    }
+  }
+  return rc;
+}
+
+/*
+** The xRollbackTo() method.
+**
+** Discard the contents of the pending terms table.
+*/
+static int fts5RollbackToMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  int rc = SQLITE_OK;
+  fts5CheckTransactionState(pTab, FTS5_ROLLBACKTO, iSavepoint);
+  fts5TripCursors(pTab);
+  if( (iSavepoint+1)<=pTab->iSavepoint ){
+    pTab->p.pConfig->pgsz = 0;
+    rc = sqlite3Fts5StorageRollback(pTab->pStorage);
+  }
+  return rc;
+}
+
+/*
+** Register a new auxiliary function with global context pGlobal.
+*/
+static int fts5CreateAux(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  fts5_extension_function xFunc,  /* Aux. function implementation */
+  void(*xDestroy)(void*)          /* Destructor for pUserData */
+){
+  Fts5Global *pGlobal = (Fts5Global*)pApi;
+  int rc = sqlite3_overload_function(pGlobal->db, zName, -1);
+  if( rc==SQLITE_OK ){
+    Fts5Auxiliary *pAux;
+    sqlite3_int64 nName;            /* Size of zName in bytes, including \0 */
+    sqlite3_int64 nByte;            /* Bytes of space to allocate */
+
+    nName = strlen(zName) + 1;
+    nByte = sizeof(Fts5Auxiliary) + nName;
+    pAux = (Fts5Auxiliary*)sqlite3_malloc64(nByte);
+    if( pAux ){
+      memset(pAux, 0, (size_t)nByte);
+      pAux->zFunc = (char*)&pAux[1];
+      memcpy(pAux->zFunc, zName, nName);
+      pAux->pGlobal = pGlobal;
+      pAux->pUserData = pUserData;
+      pAux->xFunc = xFunc;
+      pAux->xDestroy = xDestroy;
+      pAux->pNext = pGlobal->pAux;
+      pGlobal->pAux = pAux;
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is used by xCreateTokenizer_v2() and xCreateTokenizer().
+** It allocates and partially populates a new Fts5TokenizerModule object.
+** The new object is already linked into the Fts5Global context before
+** returning.
+**
+** If successful, SQLITE_OK is returned and a pointer to the new
+** Fts5TokenizerModule object returned via output parameter (*ppNew). All
+** that is required is for the caller to fill in the methods in
+** Fts5TokenizerModule.x1 and x2, and to set Fts5TokenizerModule.bV2Native
+** as appropriate.
+**
+** If an error occurs, an SQLite error code is returned and the final value
+** of (*ppNew) undefined.
+*/
+static int fts5NewTokenizerModule(
+  Fts5Global *pGlobal,            /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  void(*xDestroy)(void*),         /* Destructor for pUserData */
+  Fts5TokenizerModule **ppNew
+){
+  int rc = SQLITE_OK;
+  Fts5TokenizerModule *pNew;
+  sqlite3_int64 nName;          /* Size of zName and its \0 terminator */
+  sqlite3_int64 nByte;          /* Bytes of space to allocate */
+
+  nName = strlen(zName) + 1;
+  nByte = sizeof(Fts5TokenizerModule) + nName;
+  *ppNew = pNew = (Fts5TokenizerModule*)sqlite3Fts5MallocZero(&rc, nByte);
+  if( pNew ){
+    pNew->zName = (char*)&pNew[1];
+    memcpy(pNew->zName, zName, nName);
+    pNew->pUserData = pUserData;
+    pNew->xDestroy = xDestroy;
+    pNew->pNext = pGlobal->pTok;
+    pGlobal->pTok = pNew;
+    if( pNew->pNext==0 ){
+      pGlobal->pDfltTok = pNew;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** An instance of this type is used as the Fts5Tokenizer object for
+** wrapper tokenizers - those that provide access to a v1 tokenizer via
+** the fts5_tokenizer_v2 API, and those that provide access to a v2 tokenizer
+** via the fts5_tokenizer API.
+*/
+typedef struct Fts5VtoVTokenizer Fts5VtoVTokenizer;
+struct Fts5VtoVTokenizer {
+  int bV2Native;                  /* True if v2 native tokenizer */
+  fts5_tokenizer x1;              /* Tokenizer functions */
+  fts5_tokenizer_v2 x2;           /* V2 tokenizer functions */
+  Fts5Tokenizer *pReal;
+};
+
+/*
+** Create a wrapper tokenizer. The context argument pCtx points to the
+** Fts5TokenizerModule object.
+*/
+static int fts5VtoVCreate(
+  void *pCtx,
+  const char **azArg,
+  int nArg,
+  Fts5Tokenizer **ppOut
+){
+  Fts5TokenizerModule *pMod = (Fts5TokenizerModule*)pCtx;
+  Fts5VtoVTokenizer *pNew = 0;
+  int rc = SQLITE_OK;
+
+  pNew = (Fts5VtoVTokenizer*)sqlite3Fts5MallocZero(&rc, sizeof(*pNew));
+  if( rc==SQLITE_OK ){
+    pNew->x1 = pMod->x1;
+    pNew->x2 = pMod->x2;
+    pNew->bV2Native = pMod->bV2Native;
+    if( pMod->bV2Native ){
+      rc = pMod->x2.xCreate(pMod->pUserData, azArg, nArg, &pNew->pReal);
+    }else{
+      rc = pMod->x1.xCreate(pMod->pUserData, azArg, nArg, &pNew->pReal);
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(pNew);
+      pNew = 0;
+    }
+  }
+
+  *ppOut = (Fts5Tokenizer*)pNew;
+  return rc;
+}
+
+/*
+** Delete an Fts5VtoVTokenizer wrapper tokenizer.
+*/
+static void fts5VtoVDelete(Fts5Tokenizer *pTok){
+  Fts5VtoVTokenizer *p = (Fts5VtoVTokenizer*)pTok;
+  if( p ){
+    if( p->bV2Native ){
+      p->x2.xDelete(p->pReal);
+    }else{
+      p->x1.xDelete(p->pReal);
+    }
+    sqlite3_free(p);
+  }
+}
+
+
+/*
+** xTokenizer method for a wrapper tokenizer that offers the v1 interface
+** (no support for locales).
+*/
+static int fts5V1toV2Tokenize(
+  Fts5Tokenizer *pTok,
+  void *pCtx, int flags,
+  const char *pText, int nText,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  Fts5VtoVTokenizer *p = (Fts5VtoVTokenizer*)pTok;
+  assert( p->bV2Native );
+  return p->x2.xTokenize(p->pReal, pCtx, flags, pText, nText, 0, 0, xToken);
+}
+
+/*
+** xTokenizer method for a wrapper tokenizer that offers the v2 interface
+** (with locale support).
+*/
+static int fts5V2toV1Tokenize(
+  Fts5Tokenizer *pTok,
+  void *pCtx, int flags,
+  const char *pText, int nText,
+  const char *pLocale, int nLocale,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  Fts5VtoVTokenizer *p = (Fts5VtoVTokenizer*)pTok;
+  assert( p->bV2Native==0 );
+  UNUSED_PARAM2(pLocale,nLocale);
+  return p->x1.xTokenize(p->pReal, pCtx, flags, pText, nText, xToken);
+}
+
+/*
+** Register a new tokenizer. This is the implementation of the
+** fts5_api.xCreateTokenizer_v2() method.
+*/
+static int fts5CreateTokenizer_v2(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  fts5_tokenizer_v2 *pTokenizer,  /* Tokenizer implementation */
+  void(*xDestroy)(void*)          /* Destructor for pUserData */
+){
+  Fts5Global *pGlobal = (Fts5Global*)pApi;
+  int rc = SQLITE_OK;
+
+  if( pTokenizer->iVersion>2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    Fts5TokenizerModule *pNew = 0;
+    rc = fts5NewTokenizerModule(pGlobal, zName, pUserData, xDestroy, &pNew);
+    if( pNew ){
+      pNew->x2 = *pTokenizer;
+      pNew->bV2Native = 1;
+      pNew->x1.xCreate = fts5VtoVCreate;
+      pNew->x1.xTokenize = fts5V1toV2Tokenize;
+      pNew->x1.xDelete = fts5VtoVDelete;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The fts5_api.xCreateTokenizer() method.
+*/
+static int fts5CreateTokenizer(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  fts5_tokenizer *pTokenizer,     /* Tokenizer implementation */
+  void(*xDestroy)(void*)          /* Destructor for pUserData */
+){
+  Fts5TokenizerModule *pNew = 0;
+  int rc = SQLITE_OK;
+
+  rc = fts5NewTokenizerModule(
+      (Fts5Global*)pApi, zName, pUserData, xDestroy, &pNew
+  );
+  if( pNew ){
+    pNew->x1 = *pTokenizer;
+    pNew->x2.xCreate = fts5VtoVCreate;
+    pNew->x2.xTokenize = fts5V2toV1Tokenize;
+    pNew->x2.xDelete = fts5VtoVDelete;
+  }
+  return rc;
+}
+
+/*
+** Search the global context passed as the first argument for a tokenizer
+** module named zName. If found, return a pointer to the Fts5TokenizerModule
+** object. Otherwise, return NULL.
+*/
+static Fts5TokenizerModule *fts5LocateTokenizer(
+  Fts5Global *pGlobal,            /* Global (one per db handle) object */
+  const char *zName               /* Name of tokenizer module to find */
+){
+  Fts5TokenizerModule *pMod = 0;
+
+  if( zName==0 ){
+    pMod = pGlobal->pDfltTok;
+  }else{
+    for(pMod=pGlobal->pTok; pMod; pMod=pMod->pNext){
+      if( sqlite3_stricmp(zName, pMod->zName)==0 ) break;
+    }
+  }
+
+  return pMod;
+}
+
+/*
+** Find a tokenizer. This is the implementation of the
+** fts5_api.xFindTokenizer_v2() method.
+*/
+static int fts5FindTokenizer_v2(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of tokenizer */
+  void **ppUserData,
+  fts5_tokenizer_v2 **ppTokenizer /* Populate this object */
+){
+  int rc = SQLITE_OK;
+  Fts5TokenizerModule *pMod;
+
+  pMod = fts5LocateTokenizer((Fts5Global*)pApi, zName);
+  if( pMod ){
+    if( pMod->bV2Native ){
+      *ppUserData = pMod->pUserData;
+    }else{
+      *ppUserData = (void*)pMod;
+    }
+    *ppTokenizer = &pMod->x2;
+  }else{
+    *ppTokenizer = 0;
+    *ppUserData = 0;
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+/*
+** Find a tokenizer. This is the implementation of the
+** fts5_api.xFindTokenizer() method.
+*/
+static int fts5FindTokenizer(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void **ppUserData,
+  fts5_tokenizer *pTokenizer      /* Populate this object */
+){
+  int rc = SQLITE_OK;
+  Fts5TokenizerModule *pMod;
+
+  pMod = fts5LocateTokenizer((Fts5Global*)pApi, zName);
+  if( pMod ){
+    if( pMod->bV2Native==0 ){
+      *ppUserData = pMod->pUserData;
+    }else{
+      *ppUserData = (void*)pMod;
+    }
+    *pTokenizer = pMod->x1;
+  }else{
+    memset(pTokenizer, 0, sizeof(*pTokenizer));
+    *ppUserData = 0;
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+/*
+** Attempt to instantiate the tokenizer.
+*/
+static int sqlite3Fts5LoadTokenizer(Fts5Config *pConfig){
+  const char **azArg = pConfig->t.azArg;
+  const int nArg = pConfig->t.nArg;
+  Fts5TokenizerModule *pMod = 0;
+  int rc = SQLITE_OK;
+
+  pMod = fts5LocateTokenizer(pConfig->pGlobal, nArg==0 ? 0 : azArg[0]);
+  if( pMod==0 ){
+    assert( nArg>0 );
+    rc = SQLITE_ERROR;
+    sqlite3Fts5ConfigErrmsg(pConfig, "no such tokenizer: %s", azArg[0]);
+  }else{
+    int (*xCreate)(void*, const char**, int, Fts5Tokenizer**) = 0;
+    if( pMod->bV2Native ){
+      xCreate = pMod->x2.xCreate;
+      pConfig->t.pApi2 = &pMod->x2;
+    }else{
+      pConfig->t.pApi1 = &pMod->x1;
+      xCreate = pMod->x1.xCreate;
+    }
+
+    rc = xCreate(pMod->pUserData,
+        (azArg?&azArg[1]:0), (nArg?nArg-1:0), &pConfig->t.pTok
+    );
+
+    if( rc!=SQLITE_OK ){
+      if( rc!=SQLITE_NOMEM ){
+        sqlite3Fts5ConfigErrmsg(pConfig, "error in tokenizer constructor");
+      }
+    }else if( pMod->bV2Native==0 ){
+      pConfig->t.ePattern = sqlite3Fts5TokenizerPattern(
+          pMod->x1.xCreate, pConfig->t.pTok
+      );
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    pConfig->t.pApi1 = 0;
+    pConfig->t.pApi2 = 0;
+    pConfig->t.pTok = 0;
+  }
+
+  return rc;
+}
+
+
+/*
+** xDestroy callback passed to sqlite3_create_module(). This is invoked
+** when the db handle is being closed. Free memory associated with
+** tokenizers and aux functions registered with this db handle.
+*/
+static void fts5ModuleDestroy(void *pCtx){
+  Fts5TokenizerModule *pTok, *pNextTok;
+  Fts5Auxiliary *pAux, *pNextAux;
+  Fts5Global *pGlobal = (Fts5Global*)pCtx;
+
+  for(pAux=pGlobal->pAux; pAux; pAux=pNextAux){
+    pNextAux = pAux->pNext;
+    if( pAux->xDestroy ) pAux->xDestroy(pAux->pUserData);
+    sqlite3_free(pAux);
+  }
+
+  for(pTok=pGlobal->pTok; pTok; pTok=pNextTok){
+    pNextTok = pTok->pNext;
+    if( pTok->xDestroy ) pTok->xDestroy(pTok->pUserData);
+    sqlite3_free(pTok);
+  }
+
+  sqlite3_free(pGlobal);
+}
+
+/*
+** Implementation of the fts5() function used by clients to obtain the
+** API pointer.
+*/
+static void fts5Fts5Func(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apArg           /* Function arguments */
+){
+  Fts5Global *pGlobal = (Fts5Global*)sqlite3_user_data(pCtx);
+  fts5_api **ppApi;
+  UNUSED_PARAM(nArg);
+  assert( nArg==1 );
+  ppApi = (fts5_api**)sqlite3_value_pointer(apArg[0], "fts5_api_ptr");
+  if( ppApi ) *ppApi = &pGlobal->api;
+}
+
+/*
+** Implementation of fts5_source_id() function.
+*/
+static void fts5SourceIdFunc(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apUnused        /* Function arguments */
+){
+  assert( nArg==0 );
+  UNUSED_PARAM2(nArg, apUnused);
+  sqlite3_result_text(pCtx, "fts5: 2025-05-07 10:39:52 17144570b0d96ae63cd6f3edca39e27ebd74925252bbaf6723bcb2f6b4861fb1", -1, SQLITE_TRANSIENT);
+}
+
+/*
+** Implementation of fts5_locale(LOCALE, TEXT) function.
+**
+** If parameter LOCALE is NULL, or a zero-length string, then a copy of
+** TEXT is returned. Otherwise, both LOCALE and TEXT are interpreted as
+** text, and the value returned is a blob consisting of:
+**
+**     * The 4 bytes 0x00, 0xE0, 0xB2, 0xEb (FTS5_LOCALE_HEADER).
+**     * The LOCALE, as utf-8 text, followed by
+**     * 0x00, followed by
+**     * The TEXT, as utf-8 text.
+**
+** There is no final nul-terminator following the TEXT value.
+*/
+static void fts5LocaleFunc(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apArg           /* Function arguments */
+){
+  const char *zLocale = 0;
+  int nLocale = 0;
+  const char *zText = 0;
+  int nText = 0;
+
+  assert( nArg==2 );
+  UNUSED_PARAM(nArg);
+
+  zLocale = (const char*)sqlite3_value_text(apArg[0]);
+  nLocale = sqlite3_value_bytes(apArg[0]);
+
+  zText = (const char*)sqlite3_value_text(apArg[1]);
+  nText = sqlite3_value_bytes(apArg[1]);
+
+  if( zLocale==0 || zLocale[0]=='\0' ){
+    sqlite3_result_text(pCtx, zText, nText, SQLITE_TRANSIENT);
+  }else{
+    Fts5Global *p = (Fts5Global*)sqlite3_user_data(pCtx);
+    u8 *pBlob = 0;
+    u8 *pCsr = 0;
+    int nBlob = 0;
+
+    nBlob = FTS5_LOCALE_HDR_SIZE + nLocale + 1 + nText;
+    pBlob = (u8*)sqlite3_malloc(nBlob);
+    if( pBlob==0 ){
+      sqlite3_result_error_nomem(pCtx);
+      return;
+    }
+
+    pCsr = pBlob;
+    memcpy(pCsr, (const u8*)p->aLocaleHdr, FTS5_LOCALE_HDR_SIZE);
+    pCsr += FTS5_LOCALE_HDR_SIZE;
+    memcpy(pCsr, zLocale, nLocale);
+    pCsr += nLocale;
+    (*pCsr++) = 0x00;
+    if( zText ) memcpy(pCsr, zText, nText);
+    assert( &pCsr[nText]==&pBlob[nBlob] );
+
+    sqlite3_result_blob(pCtx, pBlob, nBlob, sqlite3_free);
+  }
+}
+
+/*
+** Implementation of fts5_insttoken() function.
+*/
+static void fts5InsttokenFunc(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apArg           /* Function arguments */
+){
+  assert( nArg==1 );
+  (void)nArg;
+  sqlite3_result_value(pCtx, apArg[0]);
+  sqlite3_result_subtype(pCtx, FTS5_INSTTOKEN_SUBTYPE);
+}
+
+/*
+** Return true if zName is the extension on one of the shadow tables used
+** by this module.
+*/
+static int fts5ShadowName(const char *zName){
+  static const char *azName[] = {
+    "config", "content", "data", "docsize", "idx"
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
+    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Run an integrity check on the FTS5 data structures.  Return a string
+** if anything is found amiss.  Return a NULL pointer if everything is
+** OK.
+*/
+static int fts5IntegrityMethod(
+  sqlite3_vtab *pVtab,    /* the FTS5 virtual table to check */
+  const char *zSchema,    /* Name of schema in which this table lives */
+  const char *zTabname,   /* Name of the table itself */
+  int isQuick,            /* True if this is a quick-check */
+  char **pzErr            /* Write error message here */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  int rc;
+
+  assert( pzErr!=0 && *pzErr==0 );
+  UNUSED_PARAM(isQuick);
+  assert( pTab->p.pConfig->pzErrmsg==0 );
+  pTab->p.pConfig->pzErrmsg = pzErr;
+  rc = sqlite3Fts5StorageIntegrity(pTab->pStorage, 0);
+  if( *pzErr==0 && rc!=SQLITE_OK ){
+    if( (rc&0xff)==SQLITE_CORRUPT ){
+      *pzErr = sqlite3_mprintf("malformed inverted index for FTS5 table %s.%s",
+          zSchema, zTabname);
+      rc = (*pzErr) ? SQLITE_OK : SQLITE_NOMEM;
+    }else{
+      *pzErr = sqlite3_mprintf("unable to validate the inverted index for"
+          " FTS5 table %s.%s: %s",
+          zSchema, zTabname, sqlite3_errstr(rc));
+    }
+  }
+
+  sqlite3Fts5IndexCloseReader(pTab->p.pIndex);
+  pTab->p.pConfig->pzErrmsg = 0;
+
+  return rc;
+}
+
+static int fts5Init(sqlite3 *db){
+  static const sqlite3_module fts5Mod = {
+    /* iVersion      */ 4,
+    /* xCreate       */ fts5CreateMethod,
+    /* xConnect      */ fts5ConnectMethod,
+    /* xBestIndex    */ fts5BestIndexMethod,
+    /* xDisconnect   */ fts5DisconnectMethod,
+    /* xDestroy      */ fts5DestroyMethod,
+    /* xOpen         */ fts5OpenMethod,
+    /* xClose        */ fts5CloseMethod,
+    /* xFilter       */ fts5FilterMethod,
+    /* xNext         */ fts5NextMethod,
+    /* xEof          */ fts5EofMethod,
+    /* xColumn       */ fts5ColumnMethod,
+    /* xRowid        */ fts5RowidMethod,
+    /* xUpdate       */ fts5UpdateMethod,
+    /* xBegin        */ fts5BeginMethod,
+    /* xSync         */ fts5SyncMethod,
+    /* xCommit       */ fts5CommitMethod,
+    /* xRollback     */ fts5RollbackMethod,
+    /* xFindFunction */ fts5FindFunctionMethod,
+    /* xRename       */ fts5RenameMethod,
+    /* xSavepoint    */ fts5SavepointMethod,
+    /* xRelease      */ fts5ReleaseMethod,
+    /* xRollbackTo   */ fts5RollbackToMethod,
+    /* xShadowName   */ fts5ShadowName,
+    /* xIntegrity    */ fts5IntegrityMethod
+  };
+
+  int rc;
+  Fts5Global *pGlobal = 0;
+
+  pGlobal = (Fts5Global*)sqlite3_malloc(sizeof(Fts5Global));
+  if( pGlobal==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    void *p = (void*)pGlobal;
+    memset(pGlobal, 0, sizeof(Fts5Global));
+    pGlobal->db = db;
+    pGlobal->api.iVersion = 3;
+    pGlobal->api.xCreateFunction = fts5CreateAux;
+    pGlobal->api.xCreateTokenizer = fts5CreateTokenizer;
+    pGlobal->api.xFindTokenizer = fts5FindTokenizer;
+    pGlobal->api.xCreateTokenizer_v2 = fts5CreateTokenizer_v2;
+    pGlobal->api.xFindTokenizer_v2 = fts5FindTokenizer_v2;
+
+    /* Initialize pGlobal->aLocaleHdr[] to a 128-bit pseudo-random vector.
+    ** The constants below were generated randomly.  */
+    sqlite3_randomness(sizeof(pGlobal->aLocaleHdr), pGlobal->aLocaleHdr);
+    pGlobal->aLocaleHdr[0] ^= 0xF924976D;
+    pGlobal->aLocaleHdr[1] ^= 0x16596E13;
+    pGlobal->aLocaleHdr[2] ^= 0x7C80BEAA;
+    pGlobal->aLocaleHdr[3] ^= 0x9B03A67F;
+    assert( sizeof(pGlobal->aLocaleHdr)==16 );
+
+    rc = sqlite3_create_module_v2(db, "fts5", &fts5Mod, p, fts5ModuleDestroy);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5IndexInit(db);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5ExprInit(pGlobal, db);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5AuxInit(&pGlobal->api);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5TokenizerInit(&pGlobal->api);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5VocabInit(pGlobal, db);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5", 1, SQLITE_UTF8, p, fts5Fts5Func, 0, 0
+      );
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5_source_id", 0,
+          SQLITE_UTF8|SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS,
+          p, fts5SourceIdFunc, 0, 0
+      );
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5_locale", 2,
+          SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_RESULT_SUBTYPE|SQLITE_SUBTYPE,
+          p, fts5LocaleFunc, 0, 0
+      );
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5_insttoken", 1,
+          SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_RESULT_SUBTYPE,
+          p, fts5InsttokenFunc, 0, 0
+      );
+    }
+  }
+
+  /* If SQLITE_FTS5_ENABLE_TEST_MI is defined, assume that the file
+  ** fts5_test_mi.c is compiled and linked into the executable. And call
+  ** its entry point to enable the matchinfo() demo.  */
+#ifdef SQLITE_FTS5_ENABLE_TEST_MI
+  if( rc==SQLITE_OK ){
+    extern int sqlite3Fts5TestRegisterMatchinfo(sqlite3*);
+    rc = sqlite3Fts5TestRegisterMatchinfo(db);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** The following functions are used to register the module with SQLite. If
+** this module is being built as part of the SQLite core (SQLITE_CORE is
+** defined), then sqlite3_open() will call sqlite3Fts5Init() directly.
+**
+** Or, if this module is being built as a loadable extension,
+** sqlite3Fts5Init() is omitted and the two standard entry points
+** sqlite3_fts_init() and sqlite3_fts5_init() defined instead.
+*/
+#ifndef SQLITE_CORE
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_fts_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi);
+  (void)pzErrMsg;  /* Unused parameter */
+  return fts5Init(db);
+}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_fts5_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi);
+  (void)pzErrMsg;  /* Unused parameter */
+  return fts5Init(db);
+}
+#else
+SQLITE_PRIVATE int sqlite3Fts5Init(sqlite3 *db){
+  return fts5Init(db);
+}
+#endif
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+
+
+
+/* #include "fts5Int.h" */
+
+/*
+** pSavedRow:
+**   SQL statement FTS5_STMT_LOOKUP2 is a copy of FTS5_STMT_LOOKUP, it
+**   does a by-rowid lookup to retrieve a single row from the %_content
+**   table or equivalent external-content table/view.
+**
+**   However, FTS5_STMT_LOOKUP2 is only used when retrieving the original
+**   values for a row being UPDATEd. In that case, the SQL statement is
+**   not reset and pSavedRow is set to point at it. This is so that the
+**   insert operation that follows the delete may access the original
+**   row values for any new values for which sqlite3_value_nochange() returns
+**   true. i.e. if the user executes:
+**
+**        CREATE VIRTUAL TABLE ft USING fts5(a, b, c, locale=1);
+**        ...
+**        UPDATE fts SET a=?, b=? WHERE rowid=?;
+**
+**   then the value passed to the xUpdate() method of this table as the
+**   new.c value is an sqlite3_value_nochange() value. So in this case it
+**   must be read from the saved row stored in Fts5Storage.pSavedRow.
+**
+**   This is necessary - using sqlite3_value_nochange() instead of just having
+**   SQLite pass the original value back via xUpdate() - so as not to discard
+**   any locale information associated with such values.
+**
+*/
+struct Fts5Storage {
+  Fts5Config *pConfig;
+  Fts5Index *pIndex;
+  int bTotalsValid;               /* True if nTotalRow/aTotalSize[] are valid */
+  i64 nTotalRow;                  /* Total number of rows in FTS table */
+  i64 *aTotalSize;                /* Total sizes of each column */
+  sqlite3_stmt *pSavedRow;
+  sqlite3_stmt *aStmt[12];
+};
+
+
+#if FTS5_STMT_SCAN_ASC!=0
+# error "FTS5_STMT_SCAN_ASC mismatch"
+#endif
+#if FTS5_STMT_SCAN_DESC!=1
+# error "FTS5_STMT_SCAN_DESC mismatch"
+#endif
+#if FTS5_STMT_LOOKUP!=2
+# error "FTS5_STMT_LOOKUP mismatch"
+#endif
+
+#define FTS5_STMT_LOOKUP2         3
+#define FTS5_STMT_INSERT_CONTENT  4
+#define FTS5_STMT_REPLACE_CONTENT 5
+#define FTS5_STMT_DELETE_CONTENT  6
+#define FTS5_STMT_REPLACE_DOCSIZE 7
+#define FTS5_STMT_DELETE_DOCSIZE  8
+#define FTS5_STMT_LOOKUP_DOCSIZE  9
+#define FTS5_STMT_REPLACE_CONFIG 10
+#define FTS5_STMT_SCAN           11
+
+/*
+** Prepare the two insert statements - Fts5Storage.pInsertContent and
+** Fts5Storage.pInsertDocsize - if they have not already been prepared.
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int fts5StorageGetStmt(
+  Fts5Storage *p,                 /* Storage handle */
+  int eStmt,                      /* FTS5_STMT_XXX constant */
+  sqlite3_stmt **ppStmt,          /* OUT: Prepared statement handle */
+  char **pzErrMsg                 /* OUT: Error message (if any) */
+){
+  int rc = SQLITE_OK;
+
+  /* If there is no %_docsize table, there should be no requests for
+  ** statements to operate on it.  */
+  assert( p->pConfig->bColumnsize || (
+        eStmt!=FTS5_STMT_REPLACE_DOCSIZE
+     && eStmt!=FTS5_STMT_DELETE_DOCSIZE
+     && eStmt!=FTS5_STMT_LOOKUP_DOCSIZE
+  ));
+
+  assert( eStmt>=0 && eStmt<ArraySize(p->aStmt) );
+  if( p->aStmt[eStmt]==0 ){
+    const char *azStmt[] = {
+      "SELECT %s FROM %s T WHERE T.%Q >= ? AND T.%Q <= ? ORDER BY T.%Q ASC",
+      "SELECT %s FROM %s T WHERE T.%Q <= ? AND T.%Q >= ? ORDER BY T.%Q DESC",
+      "SELECT %s FROM %s T WHERE T.%Q=?",               /* LOOKUP  */
+      "SELECT %s FROM %s T WHERE T.%Q=?",               /* LOOKUP2  */
+
+      "INSERT INTO %Q.'%q_content' VALUES(%s)",         /* INSERT_CONTENT  */
+      "REPLACE INTO %Q.'%q_content' VALUES(%s)",        /* REPLACE_CONTENT */
+      "DELETE FROM %Q.'%q_content' WHERE id=?",         /* DELETE_CONTENT  */
+      "REPLACE INTO %Q.'%q_docsize' VALUES(?,?%s)",     /* REPLACE_DOCSIZE  */
+      "DELETE FROM %Q.'%q_docsize' WHERE id=?",         /* DELETE_DOCSIZE  */
+
+      "SELECT sz%s FROM %Q.'%q_docsize' WHERE id=?",    /* LOOKUP_DOCSIZE  */
+
+      "REPLACE INTO %Q.'%q_config' VALUES(?,?)",        /* REPLACE_CONFIG */
+      "SELECT %s FROM %s AS T",                         /* SCAN */
+    };
+    Fts5Config *pC = p->pConfig;
+    char *zSql = 0;
+
+    assert( ArraySize(azStmt)==ArraySize(p->aStmt) );
+
+    switch( eStmt ){
+      case FTS5_STMT_SCAN:
+        zSql = sqlite3_mprintf(azStmt[eStmt],
+            pC->zContentExprlist, pC->zContent
+        );
+        break;
+
+      case FTS5_STMT_SCAN_ASC:
+      case FTS5_STMT_SCAN_DESC:
+        zSql = sqlite3_mprintf(azStmt[eStmt], pC->zContentExprlist,
+            pC->zContent, pC->zContentRowid, pC->zContentRowid,
+            pC->zContentRowid
+        );
+        break;
+
+      case FTS5_STMT_LOOKUP:
+      case FTS5_STMT_LOOKUP2:
+        zSql = sqlite3_mprintf(azStmt[eStmt],
+            pC->zContentExprlist, pC->zContent, pC->zContentRowid
+        );
+        break;
+
+      case FTS5_STMT_INSERT_CONTENT:
+      case FTS5_STMT_REPLACE_CONTENT: {
+        char *zBind = 0;
+        int i;
+
+        assert( pC->eContent==FTS5_CONTENT_NORMAL
+             || pC->eContent==FTS5_CONTENT_UNINDEXED
+        );
+
+        /* Add bindings for the "c*" columns - those that store the actual
+        ** table content. If eContent==NORMAL, then there is one binding
+        ** for each column. Or, if eContent==UNINDEXED, then there are only
+        ** bindings for the UNINDEXED columns. */
+        for(i=0; rc==SQLITE_OK && i<(pC->nCol+1); i++){
+          if( !i || pC->eContent==FTS5_CONTENT_NORMAL || pC->abUnindexed[i-1] ){
+            zBind = sqlite3Fts5Mprintf(&rc, "%z%s?%d", zBind, zBind?",":"",i+1);
+          }
+        }
+
+        /* Add bindings for any "l*" columns. Only non-UNINDEXED columns
+        ** require these.  */
+        if( pC->bLocale && pC->eContent==FTS5_CONTENT_NORMAL ){
+          for(i=0; rc==SQLITE_OK && i<pC->nCol; i++){
+            if( pC->abUnindexed[i]==0 ){
+              zBind = sqlite3Fts5Mprintf(&rc, "%z,?%d", zBind, pC->nCol+i+2);
+            }
+          }
+        }
+
+        zSql = sqlite3Fts5Mprintf(&rc, azStmt[eStmt], pC->zDb, pC->zName,zBind);
+        sqlite3_free(zBind);
+        break;
+      }
+
+      case FTS5_STMT_REPLACE_DOCSIZE:
+        zSql = sqlite3_mprintf(azStmt[eStmt], pC->zDb, pC->zName,
+          (pC->bContentlessDelete ? ",?" : "")
+        );
+        break;
+
+      case FTS5_STMT_LOOKUP_DOCSIZE:
+        zSql = sqlite3_mprintf(azStmt[eStmt],
+            (pC->bContentlessDelete ? ",origin" : ""),
+            pC->zDb, pC->zName
+        );
+        break;
+
+      default:
+        zSql = sqlite3_mprintf(azStmt[eStmt], pC->zDb, pC->zName);
+        break;
+    }
+
+    if( zSql==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      int f = SQLITE_PREPARE_PERSISTENT;
+      if( eStmt>FTS5_STMT_LOOKUP2 ) f |= SQLITE_PREPARE_NO_VTAB;
+      p->pConfig->bLock++;
+      rc = sqlite3_prepare_v3(pC->db, zSql, -1, f, &p->aStmt[eStmt], 0);
+      p->pConfig->bLock--;
+      sqlite3_free(zSql);
+      if( rc!=SQLITE_OK && pzErrMsg ){
+        *pzErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pC->db));
+      }
+      if( rc==SQLITE_ERROR && eStmt>FTS5_STMT_LOOKUP2 && eStmt<FTS5_STMT_SCAN ){
+        /* One of the internal tables - not the %_content table - is missing.
+        ** This counts as a corrupted table.  */
+       rc = SQLITE_CORRUPT;
+      }
+    }
+  }
+
+  *ppStmt = p->aStmt[eStmt];
+  sqlite3_reset(*ppStmt);
+  return rc;
+}
+
+
+static int fts5ExecPrintf(
+  sqlite3 *db,
+  char **pzErr,
+  const char *zFormat,
+  ...
+){
+  int rc;
+  va_list ap;                     /* ... printf arguments */
+  char *zSql;
+
+  va_start(ap, zFormat);
+  zSql = sqlite3_vmprintf(zFormat, ap);
+
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_exec(db, zSql, 0, 0, pzErr);
+    sqlite3_free(zSql);
+  }
+
+  va_end(ap);
+  return rc;
+}
+
+/*
+** Drop all shadow tables. Return SQLITE_OK if successful or an SQLite error
+** code otherwise.
+*/
+static int sqlite3Fts5DropAll(Fts5Config *pConfig){
+  int rc = fts5ExecPrintf(pConfig->db, 0,
+      "DROP TABLE IF EXISTS %Q.'%q_data';"
+      "DROP TABLE IF EXISTS %Q.'%q_idx';"
+      "DROP TABLE IF EXISTS %Q.'%q_config';",
+      pConfig->zDb, pConfig->zName,
+      pConfig->zDb, pConfig->zName,
+      pConfig->zDb, pConfig->zName
+  );
+  if( rc==SQLITE_OK && pConfig->bColumnsize ){
+    rc = fts5ExecPrintf(pConfig->db, 0,
+        "DROP TABLE IF EXISTS %Q.'%q_docsize';",
+        pConfig->zDb, pConfig->zName
+    );
+  }
+  if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_NORMAL ){
+    rc = fts5ExecPrintf(pConfig->db, 0,
+        "DROP TABLE IF EXISTS %Q.'%q_content';",
+        pConfig->zDb, pConfig->zName
+    );
+  }
+  return rc;
+}
+
+static void fts5StorageRenameOne(
+  Fts5Config *pConfig,            /* Current FTS5 configuration */
+  int *pRc,                       /* IN/OUT: Error code */
+  const char *zTail,              /* Tail of table name e.g. "data", "config" */
+  const char *zName               /* New name of FTS5 table */
+){
+  if( *pRc==SQLITE_OK ){
+    *pRc = fts5ExecPrintf(pConfig->db, 0,
+        "ALTER TABLE %Q.'%q_%s' RENAME TO '%q_%s';",
+        pConfig->zDb, pConfig->zName, zTail, zName, zTail
+    );
+  }
+}
+
+static int sqlite3Fts5StorageRename(Fts5Storage *pStorage, const char *zName){
+  Fts5Config *pConfig = pStorage->pConfig;
+  int rc = sqlite3Fts5StorageSync(pStorage);
+
+  fts5StorageRenameOne(pConfig, &rc, "data", zName);
+  fts5StorageRenameOne(pConfig, &rc, "idx", zName);
+  fts5StorageRenameOne(pConfig, &rc, "config", zName);
+  if( pConfig->bColumnsize ){
+    fts5StorageRenameOne(pConfig, &rc, "docsize", zName);
+  }
+  if( pConfig->eContent==FTS5_CONTENT_NORMAL ){
+    fts5StorageRenameOne(pConfig, &rc, "content", zName);
+  }
+  return rc;
+}
+
+/*
+** Create the shadow table named zPost, with definition zDefn. Return
+** SQLITE_OK if successful, or an SQLite error code otherwise.
+*/
+static int sqlite3Fts5CreateTable(
+  Fts5Config *pConfig,            /* FTS5 configuration */
+  const char *zPost,              /* Shadow table to create (e.g. "content") */
+  const char *zDefn,              /* Columns etc. for shadow table */
+  int bWithout,                   /* True for without rowid */
+  char **pzErr                    /* OUT: Error message */
+){
+  int rc;
+  char *zErr = 0;
+
+  rc = fts5ExecPrintf(pConfig->db, &zErr, "CREATE TABLE %Q.'%q_%q'(%s)%s",
+      pConfig->zDb, pConfig->zName, zPost, zDefn,
+#ifndef SQLITE_FTS5_NO_WITHOUT_ROWID
+      bWithout?" WITHOUT ROWID":
+#endif
+      ""
+  );
+  if( zErr ){
+    *pzErr = sqlite3_mprintf(
+        "fts5: error creating shadow table %q_%s: %s",
+        pConfig->zName, zPost, zErr
+    );
+    sqlite3_free(zErr);
+  }
+
+  return rc;
+}
+
+/*
+** Open a new Fts5Index handle. If the bCreate argument is true, create
+** and initialize the underlying tables
+**
+** If successful, set *pp to point to the new object and return SQLITE_OK.
+** Otherwise, set *pp to NULL and return an SQLite error code.
+*/
+static int sqlite3Fts5StorageOpen(
+  Fts5Config *pConfig,
+  Fts5Index *pIndex,
+  int bCreate,
+  Fts5Storage **pp,
+  char **pzErr                    /* OUT: Error message */
+){
+  int rc = SQLITE_OK;
+  Fts5Storage *p;                 /* New object */
+  sqlite3_int64 nByte;            /* Bytes of space to allocate */
+
+  nByte = sizeof(Fts5Storage)               /* Fts5Storage object */
+        + pConfig->nCol * sizeof(i64);      /* Fts5Storage.aTotalSize[] */
+  *pp = p = (Fts5Storage*)sqlite3_malloc64(nByte);
+  if( !p ) return SQLITE_NOMEM;
+
+  memset(p, 0, (size_t)nByte);
+  p->aTotalSize = (i64*)&p[1];
+  p->pConfig = pConfig;
+  p->pIndex = pIndex;
+
+  if( bCreate ){
+    if( pConfig->eContent==FTS5_CONTENT_NORMAL
+     || pConfig->eContent==FTS5_CONTENT_UNINDEXED
+    ){
+      int nDefn = 32 + pConfig->nCol*10;
+      char *zDefn = sqlite3_malloc64(32 + (sqlite3_int64)pConfig->nCol * 20);
+      if( zDefn==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        int i;
+        int iOff;
+        sqlite3_snprintf(nDefn, zDefn, "id INTEGER PRIMARY KEY");
+        iOff = (int)strlen(zDefn);
+        for(i=0; i<pConfig->nCol; i++){
+          if( pConfig->eContent==FTS5_CONTENT_NORMAL
+           || pConfig->abUnindexed[i]
+          ){
+            sqlite3_snprintf(nDefn-iOff, &zDefn[iOff], ", c%d", i);
+            iOff += (int)strlen(&zDefn[iOff]);
+          }
+        }
+        if( pConfig->bLocale ){
+          for(i=0; i<pConfig->nCol; i++){
+            if( pConfig->abUnindexed[i]==0 ){
+              sqlite3_snprintf(nDefn-iOff, &zDefn[iOff], ", l%d", i);
+              iOff += (int)strlen(&zDefn[iOff]);
+            }
+          }
+        }
+        rc = sqlite3Fts5CreateTable(pConfig, "content", zDefn, 0, pzErr);
+      }
+      sqlite3_free(zDefn);
+    }
+
+    if( rc==SQLITE_OK && pConfig->bColumnsize ){
+      const char *zCols = "id INTEGER PRIMARY KEY, sz BLOB";
+      if( pConfig->bContentlessDelete ){
+        zCols = "id INTEGER PRIMARY KEY, sz BLOB, origin INTEGER";
+      }
+      rc = sqlite3Fts5CreateTable(pConfig, "docsize", zCols, 0, pzErr);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5CreateTable(
+          pConfig, "config", "k PRIMARY KEY, v", 1, pzErr
+      );
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5StorageConfigValue(p, "version", 0, FTS5_CURRENT_VERSION);
+    }
+  }
+
+  if( rc ){
+    sqlite3Fts5StorageClose(p);
+    *pp = 0;
+  }
+  return rc;
+}
+
+/*
+** Close a handle opened by an earlier call to sqlite3Fts5StorageOpen().
+*/
+static int sqlite3Fts5StorageClose(Fts5Storage *p){
+  int rc = SQLITE_OK;
+  if( p ){
+    int i;
+
+    /* Finalize all SQL statements */
+    for(i=0; i<ArraySize(p->aStmt); i++){
+      sqlite3_finalize(p->aStmt[i]);
+    }
+
+    sqlite3_free(p);
+  }
+  return rc;
+}
+
+typedef struct Fts5InsertCtx Fts5InsertCtx;
+struct Fts5InsertCtx {
+  Fts5Storage *pStorage;
+  int iCol;
+  int szCol;                      /* Size of column value in tokens */
+};
+
+/*
+** Tokenization callback used when inserting tokens into the FTS index.
+*/
+static int fts5StorageInsertCallback(
+  void *pContext,                 /* Pointer to Fts5InsertCtx object */
+  int tflags,
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iUnused1,                   /* Start offset of token */
+  int iUnused2                    /* End offset of token */
+){
+  Fts5InsertCtx *pCtx = (Fts5InsertCtx*)pContext;
+  Fts5Index *pIdx = pCtx->pStorage->pIndex;
+  UNUSED_PARAM2(iUnused1, iUnused2);
+  if( nToken>FTS5_MAX_TOKEN_SIZE ) nToken = FTS5_MAX_TOKEN_SIZE;
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 || pCtx->szCol==0 ){
+    pCtx->szCol++;
+  }
+  return sqlite3Fts5IndexWrite(pIdx, pCtx->iCol, pCtx->szCol-1, pToken, nToken);
+}
+
+/*
+** This function is used as part of an UPDATE statement that modifies the
+** rowid of a row. In that case, this function is called first to set
+** Fts5Storage.pSavedRow to point to a statement that may be used to
+** access the original values of the row being deleted - iDel.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+** It is not considered an error if row iDel does not exist. In this case
+** pSavedRow is not set and SQLITE_OK returned.
+*/
+static int sqlite3Fts5StorageFindDeleteRow(Fts5Storage *p, i64 iDel){
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pSeek = 0;
+
+  assert( p->pSavedRow==0 );
+  rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP+1, &pSeek, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pSeek, 1, iDel);
+    if( sqlite3_step(pSeek)!=SQLITE_ROW ){
+      rc = sqlite3_reset(pSeek);
+    }else{
+      p->pSavedRow = pSeek;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** If a row with rowid iDel is present in the %_content table, add the
+** delete-markers to the FTS index necessary to delete it. Do not actually
+** remove the %_content row at this time though.
+**
+** If parameter bSaveRow is true, then Fts5Storage.pSavedRow is left
+** pointing to a statement (FTS5_STMT_LOOKUP2) that may be used to access
+** the original values of the row being deleted. This is used by UPDATE
+** statements.
+*/
+static int fts5StorageDeleteFromIndex(
+  Fts5Storage *p,
+  i64 iDel,
+  sqlite3_value **apVal,
+  int bSaveRow                    /* True to set pSavedRow */
+){
+  Fts5Config *pConfig = p->pConfig;
+  sqlite3_stmt *pSeek = 0;        /* SELECT to read row iDel from %_data */
+  int rc = SQLITE_OK;             /* Return code */
+  int rc2;                        /* sqlite3_reset() return code */
+  int iCol;
+  Fts5InsertCtx ctx;
+
+  assert( bSaveRow==0 || apVal==0 );
+  assert( bSaveRow==0 || bSaveRow==1 );
+  assert( FTS5_STMT_LOOKUP2==FTS5_STMT_LOOKUP+1 );
+
+  if( apVal==0 ){
+    if( p->pSavedRow && bSaveRow ){
+      pSeek = p->pSavedRow;
+      p->pSavedRow = 0;
+    }else{
+      rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP+bSaveRow, &pSeek, 0);
+      if( rc!=SQLITE_OK ) return rc;
+      sqlite3_bind_int64(pSeek, 1, iDel);
+      if( sqlite3_step(pSeek)!=SQLITE_ROW ){
+        return sqlite3_reset(pSeek);
+      }
+    }
+  }
+
+  ctx.pStorage = p;
+  ctx.iCol = -1;
+  for(iCol=1; rc==SQLITE_OK && iCol<=pConfig->nCol; iCol++){
+    if( pConfig->abUnindexed[iCol-1]==0 ){
+      sqlite3_value *pVal = 0;
+      const char *pText = 0;
+      int nText = 0;
+      const char *pLoc = 0;
+      int nLoc = 0;
+
+      assert( pSeek==0 || apVal==0 );
+      assert( pSeek!=0 || apVal!=0 );
+      if( pSeek ){
+        pVal = sqlite3_column_value(pSeek, iCol);
+      }else{
+        pVal = apVal[iCol-1];
+      }
+
+      if( pConfig->bLocale && sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+        rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+      }else{
+        pText = (const char*)sqlite3_value_text(pVal);
+        nText = sqlite3_value_bytes(pVal);
+        if( pConfig->bLocale && pSeek ){
+          pLoc = (const char*)sqlite3_column_text(pSeek, iCol + pConfig->nCol);
+          nLoc = sqlite3_column_bytes(pSeek, iCol + pConfig->nCol);
+        }
+      }
+
+      if( rc==SQLITE_OK ){
+        sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+        ctx.szCol = 0;
+        rc = sqlite3Fts5Tokenize(pConfig, FTS5_TOKENIZE_DOCUMENT,
+            pText, nText, (void*)&ctx, fts5StorageInsertCallback
+        );
+        p->aTotalSize[iCol-1] -= (i64)ctx.szCol;
+        if( rc==SQLITE_OK && p->aTotalSize[iCol-1]<0 ){
+          rc = FTS5_CORRUPT;
+        }
+        sqlite3Fts5ClearLocale(pConfig);
+      }
+    }
+  }
+  if( rc==SQLITE_OK && p->nTotalRow<1 ){
+    rc = FTS5_CORRUPT;
+  }else{
+    p->nTotalRow--;
+  }
+
+  if( rc==SQLITE_OK && bSaveRow ){
+    assert( p->pSavedRow==0 );
+    p->pSavedRow = pSeek;
+  }else{
+    rc2 = sqlite3_reset(pSeek);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+  return rc;
+}
+
+/*
+** Reset any saved statement pSavedRow. Zero pSavedRow as well. This
+** should be called by the xUpdate() method of the fts5 table before
+** returning from any operation that may have set Fts5Storage.pSavedRow.
+*/
+static void sqlite3Fts5StorageReleaseDeleteRow(Fts5Storage *pStorage){
+  assert( pStorage->pSavedRow==0
+       || pStorage->pSavedRow==pStorage->aStmt[FTS5_STMT_LOOKUP2]
+  );
+  sqlite3_reset(pStorage->pSavedRow);
+  pStorage->pSavedRow = 0;
+}
+
+/*
+** This function is called to process a DELETE on a contentless_delete=1
+** table. It adds the tombstone required to delete the entry with rowid
+** iDel. If successful, SQLITE_OK is returned. Or, if an error occurs,
+** an SQLite error code.
+*/
+static int fts5StorageContentlessDelete(Fts5Storage *p, i64 iDel){
+  i64 iOrigin = 0;
+  sqlite3_stmt *pLookup = 0;
+  int rc = SQLITE_OK;
+
+  assert( p->pConfig->bContentlessDelete );
+  assert( p->pConfig->eContent==FTS5_CONTENT_NONE
+       || p->pConfig->eContent==FTS5_CONTENT_UNINDEXED
+  );
+
+  /* Look up the origin of the document in the %_docsize table. Store
+  ** this in stack variable iOrigin.  */
+  rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP_DOCSIZE, &pLookup, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pLookup, 1, iDel);
+    if( SQLITE_ROW==sqlite3_step(pLookup) ){
+      iOrigin = sqlite3_column_int64(pLookup, 1);
+    }
+    rc = sqlite3_reset(pLookup);
+  }
+
+  if( rc==SQLITE_OK && iOrigin!=0 ){
+    rc = sqlite3Fts5IndexContentlessDelete(p->pIndex, iOrigin, iDel);
+  }
+
+  return rc;
+}
+
+/*
+** Insert a record into the %_docsize table. Specifically, do:
+**
+**   INSERT OR REPLACE INTO %_docsize(id, sz) VALUES(iRowid, pBuf);
+**
+** If there is no %_docsize table (as happens if the columnsize=0 option
+** is specified when the FTS5 table is created), this function is a no-op.
+*/
+static int fts5StorageInsertDocsize(
+  Fts5Storage *p,                 /* Storage module to write to */
+  i64 iRowid,                     /* id value */
+  Fts5Buffer *pBuf                /* sz value */
+){
+  int rc = SQLITE_OK;
+  if( p->pConfig->bColumnsize ){
+    sqlite3_stmt *pReplace = 0;
+    rc = fts5StorageGetStmt(p, FTS5_STMT_REPLACE_DOCSIZE, &pReplace, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pReplace, 1, iRowid);
+      if( p->pConfig->bContentlessDelete ){
+        i64 iOrigin = 0;
+        rc = sqlite3Fts5IndexGetOrigin(p->pIndex, &iOrigin);
+        sqlite3_bind_int64(pReplace, 3, iOrigin);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_blob(pReplace, 2, pBuf->p, pBuf->n, SQLITE_STATIC);
+      sqlite3_step(pReplace);
+      rc = sqlite3_reset(pReplace);
+      sqlite3_bind_null(pReplace, 2);
+    }
+  }
+  return rc;
+}
+
+/*
+** Load the contents of the "averages" record from disk into the
+** p->nTotalRow and p->aTotalSize[] variables. If successful, and if
+** argument bCache is true, set the p->bTotalsValid flag to indicate
+** that the contents of aTotalSize[] and nTotalRow are valid until
+** further notice.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int fts5StorageLoadTotals(Fts5Storage *p, int bCache){
+  int rc = SQLITE_OK;
+  if( p->bTotalsValid==0 ){
+    rc = sqlite3Fts5IndexGetAverages(p->pIndex, &p->nTotalRow, p->aTotalSize);
+    p->bTotalsValid = bCache;
+  }
+  return rc;
+}
+
+/*
+** Store the current contents of the p->nTotalRow and p->aTotalSize[]
+** variables in the "averages" record on disk.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int fts5StorageSaveTotals(Fts5Storage *p){
+  int nCol = p->pConfig->nCol;
+  int i;
+  Fts5Buffer buf;
+  int rc = SQLITE_OK;
+  memset(&buf, 0, sizeof(buf));
+
+  sqlite3Fts5BufferAppendVarint(&rc, &buf, p->nTotalRow);
+  for(i=0; i<nCol; i++){
+    sqlite3Fts5BufferAppendVarint(&rc, &buf, p->aTotalSize[i]);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexSetAverages(p->pIndex, buf.p, buf.n);
+  }
+  sqlite3_free(buf.p);
+
+  return rc;
+}
+
+/*
+** Remove a row from the FTS table.
+*/
+static int sqlite3Fts5StorageDelete(
+  Fts5Storage *p,                 /* Storage object */
+  i64 iDel,                       /* Rowid to delete from table */
+  sqlite3_value **apVal,          /* Optional - values to remove from index */
+  int bSaveRow                    /* If true, set pSavedRow for deleted row */
+){
+  Fts5Config *pConfig = p->pConfig;
+  int rc;
+  sqlite3_stmt *pDel = 0;
+
+  assert( pConfig->eContent!=FTS5_CONTENT_NORMAL || apVal==0 );
+  rc = fts5StorageLoadTotals(p, 1);
+
+  /* Delete the index records */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexBeginWrite(p->pIndex, 1, iDel);
+  }
+
+  if( rc==SQLITE_OK ){
+    if( p->pConfig->bContentlessDelete ){
+      rc = fts5StorageContentlessDelete(p, iDel);
+      if( rc==SQLITE_OK
+       && bSaveRow
+       && p->pConfig->eContent==FTS5_CONTENT_UNINDEXED
+      ){
+        rc = sqlite3Fts5StorageFindDeleteRow(p, iDel);
+      }
+    }else{
+      rc = fts5StorageDeleteFromIndex(p, iDel, apVal, bSaveRow);
+    }
+  }
+
+  /* Delete the %_docsize record */
+  if( rc==SQLITE_OK && pConfig->bColumnsize ){
+    rc = fts5StorageGetStmt(p, FTS5_STMT_DELETE_DOCSIZE, &pDel, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDel, 1, iDel);
+      sqlite3_step(pDel);
+      rc = sqlite3_reset(pDel);
+    }
+  }
+
+  /* Delete the %_content record */
+  if( pConfig->eContent==FTS5_CONTENT_NORMAL
+   || pConfig->eContent==FTS5_CONTENT_UNINDEXED
+  ){
+    if( rc==SQLITE_OK ){
+      rc = fts5StorageGetStmt(p, FTS5_STMT_DELETE_CONTENT, &pDel, 0);
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDel, 1, iDel);
+      sqlite3_step(pDel);
+      rc = sqlite3_reset(pDel);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Delete all entries in the FTS5 index.
+*/
+static int sqlite3Fts5StorageDeleteAll(Fts5Storage *p){
+  Fts5Config *pConfig = p->pConfig;
+  int rc;
+
+  p->bTotalsValid = 0;
+
+  /* Delete the contents of the %_data and %_docsize tables. */
+  rc = fts5ExecPrintf(pConfig->db, 0,
+      "DELETE FROM %Q.'%q_data';"
+      "DELETE FROM %Q.'%q_idx';",
+      pConfig->zDb, pConfig->zName,
+      pConfig->zDb, pConfig->zName
+  );
+  if( rc==SQLITE_OK && pConfig->bColumnsize ){
+    rc = fts5ExecPrintf(pConfig->db, 0,
+        "DELETE FROM %Q.'%q_docsize';", pConfig->zDb, pConfig->zName
+    );
+  }
+
+  if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_UNINDEXED ){
+    rc = fts5ExecPrintf(pConfig->db, 0,
+        "DELETE FROM %Q.'%q_content';", pConfig->zDb, pConfig->zName
+    );
+  }
+
+  /* Reinitialize the %_data table. This call creates the initial structure
+  ** and averages records.  */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexReinit(p->pIndex);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageConfigValue(p, "version", 0, FTS5_CURRENT_VERSION);
+  }
+  return rc;
+}
+
+static int sqlite3Fts5StorageRebuild(Fts5Storage *p){
+  Fts5Buffer buf = {0,0,0};
+  Fts5Config *pConfig = p->pConfig;
+  sqlite3_stmt *pScan = 0;
+  Fts5InsertCtx ctx;
+  int rc, rc2;
+
+  memset(&ctx, 0, sizeof(Fts5InsertCtx));
+  ctx.pStorage = p;
+  rc = sqlite3Fts5StorageDeleteAll(p);
+  if( rc==SQLITE_OK ){
+    rc = fts5StorageLoadTotals(p, 1);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts5StorageGetStmt(p, FTS5_STMT_SCAN, &pScan, pConfig->pzErrmsg);
+  }
+
+  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pScan) ){
+    i64 iRowid = sqlite3_column_int64(pScan, 0);
+
+    sqlite3Fts5BufferZero(&buf);
+    rc = sqlite3Fts5IndexBeginWrite(p->pIndex, 0, iRowid);
+    for(ctx.iCol=0; rc==SQLITE_OK && ctx.iCol<pConfig->nCol; ctx.iCol++){
+      ctx.szCol = 0;
+      if( pConfig->abUnindexed[ctx.iCol]==0 ){
+        int nText = 0;            /* Size of pText in bytes */
+        const char *pText = 0;    /* Pointer to buffer containing text value */
+        int nLoc = 0;             /* Size of pLoc in bytes */
+        const char *pLoc = 0;     /* Pointer to buffer containing text value */
+
+        sqlite3_value *pVal = sqlite3_column_value(pScan, ctx.iCol+1);
+        if( pConfig->eContent==FTS5_CONTENT_EXTERNAL
+         && sqlite3Fts5IsLocaleValue(pConfig, pVal)
+        ){
+          rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+        }else{
+          pText = (const char*)sqlite3_value_text(pVal);
+          nText = sqlite3_value_bytes(pVal);
+          if( pConfig->bLocale ){
+            int iCol = ctx.iCol + 1 + pConfig->nCol;
+            pLoc = (const char*)sqlite3_column_text(pScan, iCol);
+            nLoc = sqlite3_column_bytes(pScan, iCol);
+          }
+        }
+
+        if( rc==SQLITE_OK ){
+          sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+          rc = sqlite3Fts5Tokenize(pConfig,
+              FTS5_TOKENIZE_DOCUMENT,
+              pText, nText,
+              (void*)&ctx,
+              fts5StorageInsertCallback
+          );
+          sqlite3Fts5ClearLocale(pConfig);
+        }
+      }
+      sqlite3Fts5BufferAppendVarint(&rc, &buf, ctx.szCol);
+      p->aTotalSize[ctx.iCol] += (i64)ctx.szCol;
+    }
+    p->nTotalRow++;
+
+    if( rc==SQLITE_OK ){
+      rc = fts5StorageInsertDocsize(p, iRowid, &buf);
+    }
+  }
+  sqlite3_free(buf.p);
+  rc2 = sqlite3_reset(pScan);
+  if( rc==SQLITE_OK ) rc = rc2;
+
+  /* Write the averages record */
+  if( rc==SQLITE_OK ){
+    rc = fts5StorageSaveTotals(p);
+  }
+  return rc;
+}
+
+static int sqlite3Fts5StorageOptimize(Fts5Storage *p){
+  return sqlite3Fts5IndexOptimize(p->pIndex);
+}
+
+static int sqlite3Fts5StorageMerge(Fts5Storage *p, int nMerge){
+  return sqlite3Fts5IndexMerge(p->pIndex, nMerge);
+}
+
+static int sqlite3Fts5StorageReset(Fts5Storage *p){
+  return sqlite3Fts5IndexReset(p->pIndex);
+}
+
+/*
+** Allocate a new rowid. This is used for "external content" tables when
+** a NULL value is inserted into the rowid column. The new rowid is allocated
+** by inserting a dummy row into the %_docsize table. The dummy will be
+** overwritten later.
+**
+** If the %_docsize table does not exist, SQLITE_MISMATCH is returned. In
+** this case the user is required to provide a rowid explicitly.
+*/
+static int fts5StorageNewRowid(Fts5Storage *p, i64 *piRowid){
+  int rc = SQLITE_MISMATCH;
+  if( p->pConfig->bColumnsize ){
+    sqlite3_stmt *pReplace = 0;
+    rc = fts5StorageGetStmt(p, FTS5_STMT_REPLACE_DOCSIZE, &pReplace, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_null(pReplace, 1);
+      sqlite3_bind_null(pReplace, 2);
+      sqlite3_step(pReplace);
+      rc = sqlite3_reset(pReplace);
+    }
+    if( rc==SQLITE_OK ){
+      *piRowid = sqlite3_last_insert_rowid(p->pConfig->db);
+    }
+  }
+  return rc;
+}
+
+/*
+** Insert a new row into the FTS content table.
+*/
+static int sqlite3Fts5StorageContentInsert(
+  Fts5Storage *p,
+  int bReplace,                   /* True to use REPLACE instead of INSERT */
+  sqlite3_value **apVal,
+  i64 *piRowid
+){
+  Fts5Config *pConfig = p->pConfig;
+  int rc = SQLITE_OK;
+
+  /* Insert the new row into the %_content table. */
+  if( pConfig->eContent!=FTS5_CONTENT_NORMAL
+   && pConfig->eContent!=FTS5_CONTENT_UNINDEXED
+  ){
+    if( sqlite3_value_type(apVal[1])==SQLITE_INTEGER ){
+      *piRowid = sqlite3_value_int64(apVal[1]);
+    }else{
+      rc = fts5StorageNewRowid(p, piRowid);
+    }
+  }else{
+    sqlite3_stmt *pInsert = 0;    /* Statement to write %_content table */
+    int i;                        /* Counter variable */
+
+    assert( FTS5_STMT_INSERT_CONTENT+1==FTS5_STMT_REPLACE_CONTENT );
+    assert( bReplace==0 || bReplace==1 );
+    rc = fts5StorageGetStmt(p, FTS5_STMT_INSERT_CONTENT+bReplace, &pInsert, 0);
+    if( pInsert ) sqlite3_clear_bindings(pInsert);
+
+    /* Bind the rowid value */
+    sqlite3_bind_value(pInsert, 1, apVal[1]);
+
+    /* Loop through values for user-defined columns. i=2 is the leftmost
+    ** user-defined column. As is column 1 of pSavedRow.  */
+    for(i=2; rc==SQLITE_OK && i<=pConfig->nCol+1; i++){
+      int bUnindexed = pConfig->abUnindexed[i-2];
+      if( pConfig->eContent==FTS5_CONTENT_NORMAL || bUnindexed ){
+        sqlite3_value *pVal = apVal[i];
+
+        if( sqlite3_value_nochange(pVal) && p->pSavedRow ){
+          /* This is an UPDATE statement, and user-defined column (i-2) was not
+          ** modified.  Retrieve the value from Fts5Storage.pSavedRow.  */
+          pVal = sqlite3_column_value(p->pSavedRow, i-1);
+          if( pConfig->bLocale && bUnindexed==0 ){
+            sqlite3_bind_value(pInsert, pConfig->nCol + i,
+                sqlite3_column_value(p->pSavedRow, pConfig->nCol + i - 1)
+            );
+          }
+        }else if( sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+          const char *pText = 0;
+          const char *pLoc = 0;
+          int nText = 0;
+          int nLoc = 0;
+          assert( pConfig->bLocale );
+
+          rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+          if( rc==SQLITE_OK ){
+            sqlite3_bind_text(pInsert, i, pText, nText, SQLITE_TRANSIENT);
+            if( bUnindexed==0 ){
+              int iLoc = pConfig->nCol + i;
+              sqlite3_bind_text(pInsert, iLoc, pLoc, nLoc, SQLITE_TRANSIENT);
+            }
+          }
+
+          continue;
+        }
+
+        rc = sqlite3_bind_value(pInsert, i, pVal);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3_step(pInsert);
+      rc = sqlite3_reset(pInsert);
+    }
+    *piRowid = sqlite3_last_insert_rowid(pConfig->db);
+  }
+
+  return rc;
+}
+
+/*
+** Insert new entries into the FTS index and %_docsize table.
+*/
+static int sqlite3Fts5StorageIndexInsert(
+  Fts5Storage *p,
+  sqlite3_value **apVal,
+  i64 iRowid
+){
+  Fts5Config *pConfig = p->pConfig;
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5InsertCtx ctx;              /* Tokenization callback context object */
+  Fts5Buffer buf;                 /* Buffer used to build up %_docsize blob */
+
+  memset(&buf, 0, sizeof(Fts5Buffer));
+  ctx.pStorage = p;
+  rc = fts5StorageLoadTotals(p, 1);
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexBeginWrite(p->pIndex, 0, iRowid);
+  }
+  for(ctx.iCol=0; rc==SQLITE_OK && ctx.iCol<pConfig->nCol; ctx.iCol++){
+    ctx.szCol = 0;
+    if( pConfig->abUnindexed[ctx.iCol]==0 ){
+      int nText = 0;              /* Size of pText in bytes */
+      const char *pText = 0;      /* Pointer to buffer containing text value */
+      int nLoc = 0;               /* Size of pText in bytes */
+      const char *pLoc = 0;       /* Pointer to buffer containing text value */
+
+      sqlite3_value *pVal = apVal[ctx.iCol+2];
+      if( p->pSavedRow && sqlite3_value_nochange(pVal) ){
+        pVal = sqlite3_column_value(p->pSavedRow, ctx.iCol+1);
+        if( pConfig->eContent==FTS5_CONTENT_NORMAL && pConfig->bLocale ){
+          int iCol = ctx.iCol + 1 + pConfig->nCol;
+          pLoc = (const char*)sqlite3_column_text(p->pSavedRow, iCol);
+          nLoc = sqlite3_column_bytes(p->pSavedRow, iCol);
+        }
+      }else{
+        pVal = apVal[ctx.iCol+2];
+      }
+
+      if( pConfig->bLocale && sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+        rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+      }else{
+        pText = (const char*)sqlite3_value_text(pVal);
+        nText = sqlite3_value_bytes(pVal);
+      }
+
+      if( rc==SQLITE_OK ){
+        sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+        rc = sqlite3Fts5Tokenize(pConfig,
+            FTS5_TOKENIZE_DOCUMENT, pText, nText, (void*)&ctx,
+            fts5StorageInsertCallback
+        );
+        sqlite3Fts5ClearLocale(pConfig);
+      }
+    }
+    sqlite3Fts5BufferAppendVarint(&rc, &buf, ctx.szCol);
+    p->aTotalSize[ctx.iCol] += (i64)ctx.szCol;
+  }
+  p->nTotalRow++;
+
+  /* Write the %_docsize record */
+  if( rc==SQLITE_OK ){
+    rc = fts5StorageInsertDocsize(p, iRowid, &buf);
+  }
+  sqlite3_free(buf.p);
+
+  return rc;
+}
+
+static int fts5StorageCount(Fts5Storage *p, const char *zSuffix, i64 *pnRow){
+  Fts5Config *pConfig = p->pConfig;
+  char *zSql;
+  int rc;
+
+  zSql = sqlite3_mprintf("SELECT count(*) FROM %Q.'%q_%s'",
+      pConfig->zDb, pConfig->zName, zSuffix
+  );
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_stmt *pCnt = 0;
+    rc = sqlite3_prepare_v2(pConfig->db, zSql, -1, &pCnt, 0);
+    if( rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pCnt) ){
+        *pnRow = sqlite3_column_int64(pCnt, 0);
+      }
+      rc = sqlite3_finalize(pCnt);
+    }
+  }
+
+  sqlite3_free(zSql);
+  return rc;
+}
+
+/*
+** Context object used by sqlite3Fts5StorageIntegrity().
+*/
+typedef struct Fts5IntegrityCtx Fts5IntegrityCtx;
+struct Fts5IntegrityCtx {
+  i64 iRowid;
+  int iCol;
+  int szCol;
+  u64 cksum;
+  Fts5Termset *pTermset;
+  Fts5Config *pConfig;
+};
+
+
+/*
+** Tokenization callback used by integrity check.
+*/
+static int fts5StorageIntegrityCallback(
+  void *pContext,                 /* Pointer to Fts5IntegrityCtx object */
+  int tflags,
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iUnused1,                   /* Start offset of token */
+  int iUnused2                    /* End offset of token */
+){
+  Fts5IntegrityCtx *pCtx = (Fts5IntegrityCtx*)pContext;
+  Fts5Termset *pTermset = pCtx->pTermset;
+  int bPresent;
+  int ii;
+  int rc = SQLITE_OK;
+  int iPos;
+  int iCol;
+
+  UNUSED_PARAM2(iUnused1, iUnused2);
+  if( nToken>FTS5_MAX_TOKEN_SIZE ) nToken = FTS5_MAX_TOKEN_SIZE;
+
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 || pCtx->szCol==0 ){
+    pCtx->szCol++;
+  }
+
+  switch( pCtx->pConfig->eDetail ){
+    case FTS5_DETAIL_FULL:
+      iPos = pCtx->szCol-1;
+      iCol = pCtx->iCol;
+      break;
+
+    case FTS5_DETAIL_COLUMNS:
+      iPos = pCtx->iCol;
+      iCol = 0;
+      break;
+
+    default:
+      assert( pCtx->pConfig->eDetail==FTS5_DETAIL_NONE );
+      iPos = 0;
+      iCol = 0;
+      break;
+  }
+
+  rc = sqlite3Fts5TermsetAdd(pTermset, 0, pToken, nToken, &bPresent);
+  if( rc==SQLITE_OK && bPresent==0 ){
+    pCtx->cksum ^= sqlite3Fts5IndexEntryCksum(
+        pCtx->iRowid, iCol, iPos, 0, pToken, nToken
+    );
+  }
+
+  for(ii=0; rc==SQLITE_OK && ii<pCtx->pConfig->nPrefix; ii++){
+    const int nChar = pCtx->pConfig->aPrefix[ii];
+    int nByte = sqlite3Fts5IndexCharlenToBytelen(pToken, nToken, nChar);
+    if( nByte ){
+      rc = sqlite3Fts5TermsetAdd(pTermset, ii+1, pToken, nByte, &bPresent);
+      if( bPresent==0 ){
+        pCtx->cksum ^= sqlite3Fts5IndexEntryCksum(
+            pCtx->iRowid, iCol, iPos, ii+1, pToken, nByte
+        );
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Check that the contents of the FTS index match that of the %_content
+** table. Return SQLITE_OK if they do, or SQLITE_CORRUPT if not. Return
+** some other SQLite error code if an error occurs while attempting to
+** determine this.
+*/
+static int sqlite3Fts5StorageIntegrity(Fts5Storage *p, int iArg){
+  Fts5Config *pConfig = p->pConfig;
+  int rc = SQLITE_OK;             /* Return code */
+  int *aColSize;                  /* Array of size pConfig->nCol */
+  i64 *aTotalSize;                /* Array of size pConfig->nCol */
+  Fts5IntegrityCtx ctx;
+  sqlite3_stmt *pScan;
+  int bUseCksum;
+
+  memset(&ctx, 0, sizeof(Fts5IntegrityCtx));
+  ctx.pConfig = p->pConfig;
+  aTotalSize = (i64*)sqlite3_malloc64(pConfig->nCol*(sizeof(int)+sizeof(i64)));
+  if( !aTotalSize ) return SQLITE_NOMEM;
+  aColSize = (int*)&aTotalSize[pConfig->nCol];
+  memset(aTotalSize, 0, sizeof(i64) * pConfig->nCol);
+
+  bUseCksum = (pConfig->eContent==FTS5_CONTENT_NORMAL
+           || (pConfig->eContent==FTS5_CONTENT_EXTERNAL && iArg)
+  );
+  if( bUseCksum ){
+    /* Generate the expected index checksum based on the contents of the
+    ** %_content table. This block stores the checksum in ctx.cksum. */
+    rc = fts5StorageGetStmt(p, FTS5_STMT_SCAN, &pScan, 0);
+    if( rc==SQLITE_OK ){
+      int rc2;
+      while( SQLITE_ROW==sqlite3_step(pScan) ){
+        int i;
+        ctx.iRowid = sqlite3_column_int64(pScan, 0);
+        ctx.szCol = 0;
+        if( pConfig->bColumnsize ){
+          rc = sqlite3Fts5StorageDocsize(p, ctx.iRowid, aColSize);
+        }
+        if( rc==SQLITE_OK && pConfig->eDetail==FTS5_DETAIL_NONE ){
+          rc = sqlite3Fts5TermsetNew(&ctx.pTermset);
+        }
+        for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
+          if( pConfig->abUnindexed[i]==0 ){
+            const char *pText = 0;
+            int nText = 0;
+            const char *pLoc = 0;
+            int nLoc = 0;
+            sqlite3_value *pVal = sqlite3_column_value(pScan, i+1);
+
+            if( pConfig->eContent==FTS5_CONTENT_EXTERNAL
+             && sqlite3Fts5IsLocaleValue(pConfig, pVal)
+            ){
+              rc = sqlite3Fts5DecodeLocaleValue(
+                  pVal, &pText, &nText, &pLoc, &nLoc
+              );
+            }else{
+              if( pConfig->eContent==FTS5_CONTENT_NORMAL && pConfig->bLocale ){
+                int iCol = i + 1 + pConfig->nCol;
+                pLoc = (const char*)sqlite3_column_text(pScan, iCol);
+                nLoc = sqlite3_column_bytes(pScan, iCol);
+              }
+              pText = (const char*)sqlite3_value_text(pVal);
+              nText = sqlite3_value_bytes(pVal);
+            }
+
+            ctx.iCol = i;
+            ctx.szCol = 0;
+
+            if( rc==SQLITE_OK && pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+              rc = sqlite3Fts5TermsetNew(&ctx.pTermset);
+            }
+
+            if( rc==SQLITE_OK ){
+              sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+              rc = sqlite3Fts5Tokenize(pConfig,
+                  FTS5_TOKENIZE_DOCUMENT,
+                  pText, nText,
+                  (void*)&ctx,
+                  fts5StorageIntegrityCallback
+              );
+              sqlite3Fts5ClearLocale(pConfig);
+            }
+
+            /* If this is not a columnsize=0 database, check that the number
+            ** of tokens in the value matches the aColSize[] value read from
+            ** the %_docsize table.  */
+            if( rc==SQLITE_OK
+             && pConfig->bColumnsize
+             && ctx.szCol!=aColSize[i]
+            ){
+              rc = FTS5_CORRUPT;
+            }
+            aTotalSize[i] += ctx.szCol;
+            if( pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+              sqlite3Fts5TermsetFree(ctx.pTermset);
+              ctx.pTermset = 0;
+            }
+          }
+        }
+        sqlite3Fts5TermsetFree(ctx.pTermset);
+        ctx.pTermset = 0;
+
+        if( rc!=SQLITE_OK ) break;
+      }
+      rc2 = sqlite3_reset(pScan);
+      if( rc==SQLITE_OK ) rc = rc2;
+    }
+
+    /* Test that the "totals" (sometimes called "averages") record looks Ok */
+    if( rc==SQLITE_OK ){
+      int i;
+      rc = fts5StorageLoadTotals(p, 0);
+      for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
+        if( p->aTotalSize[i]!=aTotalSize[i] ) rc = FTS5_CORRUPT;
+      }
+    }
+
+    /* Check that the %_docsize and %_content tables contain the expected
+    ** number of rows.  */
+    if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_NORMAL ){
+      i64 nRow = 0;
+      rc = fts5StorageCount(p, "content", &nRow);
+      if( rc==SQLITE_OK && nRow!=p->nTotalRow ) rc = FTS5_CORRUPT;
+    }
+    if( rc==SQLITE_OK && pConfig->bColumnsize ){
+      i64 nRow = 0;
+      rc = fts5StorageCount(p, "docsize", &nRow);
+      if( rc==SQLITE_OK && nRow!=p->nTotalRow ) rc = FTS5_CORRUPT;
+    }
+  }
+
+  /* Pass the expected checksum down to the FTS index module. It will
+  ** verify, amongst other things, that it matches the checksum generated by
+  ** inspecting the index itself.  */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexIntegrityCheck(p->pIndex, ctx.cksum, bUseCksum);
+  }
+
+  sqlite3_free(aTotalSize);
+  return rc;
+}
+
+/*
+** Obtain an SQLite statement handle that may be used to read data from the
+** %_content table.
+*/
+static int sqlite3Fts5StorageStmt(
+  Fts5Storage *p,
+  int eStmt,
+  sqlite3_stmt **pp,
+  char **pzErrMsg
+){
+  int rc;
+  assert( eStmt==FTS5_STMT_SCAN_ASC
+       || eStmt==FTS5_STMT_SCAN_DESC
+       || eStmt==FTS5_STMT_LOOKUP
+  );
+  rc = fts5StorageGetStmt(p, eStmt, pp, pzErrMsg);
+  if( rc==SQLITE_OK ){
+    assert( p->aStmt[eStmt]==*pp );
+    p->aStmt[eStmt] = 0;
+  }
+  return rc;
+}
+
+/*
+** Release an SQLite statement handle obtained via an earlier call to
+** sqlite3Fts5StorageStmt(). The eStmt parameter passed to this function
+** must match that passed to the sqlite3Fts5StorageStmt() call.
+*/
+static void sqlite3Fts5StorageStmtRelease(
+  Fts5Storage *p,
+  int eStmt,
+  sqlite3_stmt *pStmt
+){
+  assert( eStmt==FTS5_STMT_SCAN_ASC
+       || eStmt==FTS5_STMT_SCAN_DESC
+       || eStmt==FTS5_STMT_LOOKUP
+  );
+  if( p->aStmt[eStmt]==0 ){
+    sqlite3_reset(pStmt);
+    p->aStmt[eStmt] = pStmt;
+  }else{
+    sqlite3_finalize(pStmt);
+  }
+}
+
+static int fts5StorageDecodeSizeArray(
+  int *aCol, int nCol,            /* Array to populate */
+  const u8 *aBlob, int nBlob      /* Record to read varints from */
+){
+  int i;
+  int iOff = 0;
+  for(i=0; i<nCol; i++){
+    if( iOff>=nBlob ) return 1;
+    iOff += fts5GetVarint32(&aBlob[iOff], aCol[i]);
+  }
+  return (iOff!=nBlob);
+}
+
+/*
+** Argument aCol points to an array of integers containing one entry for
+** each table column. This function reads the %_docsize record for the
+** specified rowid and populates aCol[] with the results.
+**
+** An SQLite error code is returned if an error occurs, or SQLITE_OK
+** otherwise.
+*/
+static int sqlite3Fts5StorageDocsize(Fts5Storage *p, i64 iRowid, int *aCol){
+  int nCol = p->pConfig->nCol;    /* Number of user columns in table */
+  sqlite3_stmt *pLookup = 0;      /* Statement to query %_docsize */
+  int rc;                         /* Return Code */
+
+  assert( p->pConfig->bColumnsize );
+  rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP_DOCSIZE, &pLookup, 0);
+  if( pLookup ){
+    int bCorrupt = 1;
+    assert( rc==SQLITE_OK );
+    sqlite3_bind_int64(pLookup, 1, iRowid);
+    if( SQLITE_ROW==sqlite3_step(pLookup) ){
+      const u8 *aBlob = sqlite3_column_blob(pLookup, 0);
+      int nBlob = sqlite3_column_bytes(pLookup, 0);
+      if( 0==fts5StorageDecodeSizeArray(aCol, nCol, aBlob, nBlob) ){
+        bCorrupt = 0;
+      }
+    }
+    rc = sqlite3_reset(pLookup);
+    if( bCorrupt && rc==SQLITE_OK ){
+      rc = FTS5_CORRUPT;
+    }
+  }else{
+    assert( rc!=SQLITE_OK );
+  }
+
+  return rc;
+}
+
+static int sqlite3Fts5StorageSize(Fts5Storage *p, int iCol, i64 *pnToken){
+  int rc = fts5StorageLoadTotals(p, 0);
+  if( rc==SQLITE_OK ){
+    *pnToken = 0;
+    if( iCol<0 ){
+      int i;
+      for(i=0; i<p->pConfig->nCol; i++){
+        *pnToken += p->aTotalSize[i];
+      }
+    }else if( iCol<p->pConfig->nCol ){
+      *pnToken = p->aTotalSize[iCol];
+    }else{
+      rc = SQLITE_RANGE;
+    }
+  }
+  return rc;
+}
+
+static int sqlite3Fts5StorageRowCount(Fts5Storage *p, i64 *pnRow){
+  int rc = fts5StorageLoadTotals(p, 0);
+  if( rc==SQLITE_OK ){
+    /* nTotalRow being zero does not necessarily indicate a corrupt
+    ** database - it might be that the FTS5 table really does contain zero
+    ** rows. However this function is only called from the xRowCount() API,
+    ** and there is no way for that API to be invoked if the table contains
+    ** no rows. Hence the FTS5_CORRUPT return.  */
+    *pnRow = p->nTotalRow;
+    if( p->nTotalRow<=0 ) rc = FTS5_CORRUPT;
+  }
+  return rc;
+}
+
+/*
+** Flush any data currently held in-memory to disk.
+*/
+static int sqlite3Fts5StorageSync(Fts5Storage *p){
+  int rc = SQLITE_OK;
+  i64 iLastRowid = sqlite3_last_insert_rowid(p->pConfig->db);
+  if( p->bTotalsValid ){
+    rc = fts5StorageSaveTotals(p);
+    if( rc==SQLITE_OK ){
+      p->bTotalsValid = 0;
+    }
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexSync(p->pIndex);
+  }
+  sqlite3_set_last_insert_rowid(p->pConfig->db, iLastRowid);
+  return rc;
+}
+
+static int sqlite3Fts5StorageRollback(Fts5Storage *p){
+  p->bTotalsValid = 0;
+  return sqlite3Fts5IndexRollback(p->pIndex);
+}
+
+static int sqlite3Fts5StorageConfigValue(
+  Fts5Storage *p,
+  const char *z,
+  sqlite3_value *pVal,
+  int iVal
+){
+  sqlite3_stmt *pReplace = 0;
+  int rc = fts5StorageGetStmt(p, FTS5_STMT_REPLACE_CONFIG, &pReplace, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_text(pReplace, 1, z, -1, SQLITE_STATIC);
+    if( pVal ){
+      sqlite3_bind_value(pReplace, 2, pVal);
+    }else{
+      sqlite3_bind_int(pReplace, 2, iVal);
+    }
+    sqlite3_step(pReplace);
+    rc = sqlite3_reset(pReplace);
+    sqlite3_bind_null(pReplace, 1);
+  }
+  if( rc==SQLITE_OK && pVal ){
+    int iNew = p->pConfig->iCookie + 1;
+    rc = sqlite3Fts5IndexSetCookie(p->pIndex, iNew);
+    if( rc==SQLITE_OK ){
+      p->pConfig->iCookie = iNew;
+    }
+  }
+  return rc;
+}
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+
+/* #include "fts5Int.h" */
+
+/**************************************************************************
+** Start of ascii tokenizer implementation.
+*/
+
+/*
+** For tokenizers with no "unicode" modifier, the set of token characters
+** is the same as the set of ASCII range alphanumeric characters.
+*/
+static unsigned char aAsciiTokenChar[128] = {
+  0, 0, 0, 0, 0, 0, 0, 0,   0, 0, 0, 0, 0, 0, 0, 0,   /* 0x00..0x0F */
+  0, 0, 0, 0, 0, 0, 0, 0,   0, 0, 0, 0, 0, 0, 0, 0,   /* 0x10..0x1F */
+  0, 0, 0, 0, 0, 0, 0, 0,   0, 0, 0, 0, 0, 0, 0, 0,   /* 0x20..0x2F */
+  1, 1, 1, 1, 1, 1, 1, 1,   1, 1, 0, 0, 0, 0, 0, 0,   /* 0x30..0x3F */
+  0, 1, 1, 1, 1, 1, 1, 1,   1, 1, 1, 1, 1, 1, 1, 1,   /* 0x40..0x4F */
+  1, 1, 1, 1, 1, 1, 1, 1,   1, 1, 1, 0, 0, 0, 0, 0,   /* 0x50..0x5F */
+  0, 1, 1, 1, 1, 1, 1, 1,   1, 1, 1, 1, 1, 1, 1, 1,   /* 0x60..0x6F */
+  1, 1, 1, 1, 1, 1, 1, 1,   1, 1, 1, 0, 0, 0, 0, 0,   /* 0x70..0x7F */
+};
+
+typedef struct AsciiTokenizer AsciiTokenizer;
+struct AsciiTokenizer {
+  unsigned char aTokenChar[128];
+};
+
+static void fts5AsciiAddExceptions(
+  AsciiTokenizer *p,
+  const char *zArg,
+  int bTokenChars
+){
+  int i;
+  for(i=0; zArg[i]; i++){
+    if( (zArg[i] & 0x80)==0 ){
+      p->aTokenChar[(int)zArg[i]] = (unsigned char)bTokenChars;
+    }
+  }
+}
+
+/*
+** Delete a "ascii" tokenizer.
+*/
+static void fts5AsciiDelete(Fts5Tokenizer *p){
+  sqlite3_free(p);
+}
+
+/*
+** Create an "ascii" tokenizer.
+*/
+static int fts5AsciiCreate(
+  void *pUnused,
+  const char **azArg, int nArg,
+  Fts5Tokenizer **ppOut
+){
+  int rc = SQLITE_OK;
+  AsciiTokenizer *p = 0;
+  UNUSED_PARAM(pUnused);
+  if( nArg%2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    p = sqlite3_malloc(sizeof(AsciiTokenizer));
+    if( p==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      int i;
+      memset(p, 0, sizeof(AsciiTokenizer));
+      memcpy(p->aTokenChar, aAsciiTokenChar, sizeof(aAsciiTokenChar));
+      for(i=0; rc==SQLITE_OK && i<nArg; i+=2){
+        const char *zArg = azArg[i+1];
+        if( 0==sqlite3_stricmp(azArg[i], "tokenchars") ){
+          fts5AsciiAddExceptions(p, zArg, 1);
+        }else
+        if( 0==sqlite3_stricmp(azArg[i], "separators") ){
+          fts5AsciiAddExceptions(p, zArg, 0);
+        }else{
+          rc = SQLITE_ERROR;
+        }
+      }
+      if( rc!=SQLITE_OK ){
+        fts5AsciiDelete((Fts5Tokenizer*)p);
+        p = 0;
+      }
+    }
+  }
+
+  *ppOut = (Fts5Tokenizer*)p;
+  return rc;
+}
+
+
+static void asciiFold(char *aOut, const char *aIn, int nByte){
+  int i;
+  for(i=0; i<nByte; i++){
+    char c = aIn[i];
+    if( c>='A' && c<='Z' ) c += 32;
+    aOut[i] = c;
+  }
+}
+
+/*
+** Tokenize some text using the ascii tokenizer.
+*/
+static int fts5AsciiTokenize(
+  Fts5Tokenizer *pTokenizer,
+  void *pCtx,
+  int iUnused,
+  const char *pText, int nText,
+  int (*xToken)(void*, int, const char*, int nToken, int iStart, int iEnd)
+){
+  AsciiTokenizer *p = (AsciiTokenizer*)pTokenizer;
+  int rc = SQLITE_OK;
+  int ie;
+  int is = 0;
+
+  char aFold[64];
+  int nFold = sizeof(aFold);
+  char *pFold = aFold;
+  unsigned char *a = p->aTokenChar;
+
+  UNUSED_PARAM(iUnused);
+
+  while( is<nText && rc==SQLITE_OK ){
+    int nByte;
+
+    /* Skip any leading divider characters. */
+    while( is<nText && ((pText[is]&0x80)==0 && a[(int)pText[is]]==0) ){
+      is++;
+    }
+    if( is==nText ) break;
+
+    /* Count the token characters */
+    ie = is+1;
+    while( ie<nText && ((pText[ie]&0x80) || a[(int)pText[ie]] ) ){
+      ie++;
+    }
+
+    /* Fold to lower case */
+    nByte = ie-is;
+    if( nByte>nFold ){
+      if( pFold!=aFold ) sqlite3_free(pFold);
+      pFold = sqlite3_malloc64((sqlite3_int64)nByte*2);
+      if( pFold==0 ){
+        rc = SQLITE_NOMEM;
+        break;
+      }
+      nFold = nByte*2;
+    }
+    asciiFold(pFold, &pText[is], nByte);
+
+    /* Invoke the token callback */
+    rc = xToken(pCtx, 0, pFold, nByte, is, ie);
+    is = ie+1;
+  }
+
+  if( pFold!=aFold ) sqlite3_free(pFold);
+  if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  return rc;
+}
+
+/**************************************************************************
+** Start of unicode61 tokenizer implementation.
+*/
+
+
+/*
+** The following two macros - READ_UTF8 and WRITE_UTF8 - have been copied
+** from the sqlite3 source file utf.c. If this file is compiled as part
+** of the amalgamation, they are not required.
+*/
+#ifndef SQLITE_AMALGAMATION
+
+static const unsigned char sqlite3Utf8Trans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+#define READ_UTF8(zIn, zTerm, c)                           \
+  c = *(zIn++);                                            \
+  if( c>=0xc0 ){                                           \
+    c = sqlite3Utf8Trans1[c-0xc0];                         \
+    while( zIn<zTerm && (*zIn & 0xc0)==0x80 ){             \
+      c = (c<<6) + (0x3f & *(zIn++));                      \
+    }                                                      \
+    if( c<0x80                                             \
+        || (c&0xFFFFF800)==0xD800                          \
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }        \
+  }
+
+
+#define WRITE_UTF8(zOut, c) {                          \
+  if( c<0x00080 ){                                     \
+    *zOut++ = (unsigned char)(c&0xFF);                 \
+  }                                                    \
+  else if( c<0x00800 ){                                \
+    *zOut++ = 0xC0 + (unsigned char)((c>>6)&0x1F);     \
+    *zOut++ = 0x80 + (unsigned char)(c & 0x3F);        \
+  }                                                    \
+  else if( c<0x10000 ){                                \
+    *zOut++ = 0xE0 + (unsigned char)((c>>12)&0x0F);    \
+    *zOut++ = 0x80 + (unsigned char)((c>>6) & 0x3F);   \
+    *zOut++ = 0x80 + (unsigned char)(c & 0x3F);        \
+  }else{                                               \
+    *zOut++ = 0xF0 + (unsigned char)((c>>18) & 0x07);  \
+    *zOut++ = 0x80 + (unsigned char)((c>>12) & 0x3F);  \
+    *zOut++ = 0x80 + (unsigned char)((c>>6) & 0x3F);   \
+    *zOut++ = 0x80 + (unsigned char)(c & 0x3F);        \
+  }                                                    \
+}
+
+#endif /* ifndef SQLITE_AMALGAMATION */
+
+#define FTS5_SKIP_UTF8(zIn) {                               \
+  if( ((unsigned char)(*(zIn++)))>=0xc0 ){                              \
+    while( (((unsigned char)*zIn) & 0xc0)==0x80 ){ zIn++; }             \
+  }                                                    \
+}
+
+typedef struct Unicode61Tokenizer Unicode61Tokenizer;
+struct Unicode61Tokenizer {
+  unsigned char aTokenChar[128];  /* ASCII range token characters */
+  char *aFold;                    /* Buffer to fold text into */
+  int nFold;                      /* Size of aFold[] in bytes */
+  int eRemoveDiacritic;           /* True if remove_diacritics=1 is set */
+  int nException;
+  int *aiException;
+
+  unsigned char aCategory[32];    /* True for token char categories */
+};
+
+/* Values for eRemoveDiacritic (must match internals of fts5_unicode2.c) */
+#define FTS5_REMOVE_DIACRITICS_NONE    0
+#define FTS5_REMOVE_DIACRITICS_SIMPLE  1
+#define FTS5_REMOVE_DIACRITICS_COMPLEX 2
+
+static int fts5UnicodeAddExceptions(
+  Unicode61Tokenizer *p,          /* Tokenizer object */
+  const char *z,                  /* Characters to treat as exceptions */
+  int bTokenChars                 /* 1 for 'tokenchars', 0 for 'separators' */
+){
+  int rc = SQLITE_OK;
+  int n = (int)strlen(z);
+  int *aNew;
+
+  if( n>0 ){
+    aNew = (int*)sqlite3_realloc64(p->aiException,
+                                   (n+p->nException)*sizeof(int));
+    if( aNew ){
+      int nNew = p->nException;
+      const unsigned char *zCsr = (const unsigned char*)z;
+      const unsigned char *zTerm = (const unsigned char*)&z[n];
+      while( zCsr<zTerm ){
+        u32 iCode;
+        int bToken;
+        READ_UTF8(zCsr, zTerm, iCode);
+        if( iCode<128 ){
+          p->aTokenChar[iCode] = (unsigned char)bTokenChars;
+        }else{
+          bToken = p->aCategory[sqlite3Fts5UnicodeCategory(iCode)];
+          assert( (bToken==0 || bToken==1) );
+          assert( (bTokenChars==0 || bTokenChars==1) );
+          if( bToken!=bTokenChars && sqlite3Fts5UnicodeIsdiacritic(iCode)==0 ){
+            int i;
+            for(i=0; i<nNew; i++){
+              if( (u32)aNew[i]>iCode ) break;
+            }
+            memmove(&aNew[i+1], &aNew[i], (nNew-i)*sizeof(int));
+            aNew[i] = iCode;
+            nNew++;
+          }
+        }
+      }
+      p->aiException = aNew;
+      p->nException = nNew;
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Return true if the p->aiException[] array contains the value iCode.
+*/
+static int fts5UnicodeIsException(Unicode61Tokenizer *p, int iCode){
+  if( p->nException>0 ){
+    int *a = p->aiException;
+    int iLo = 0;
+    int iHi = p->nException-1;
+
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      if( iCode==a[iTest] ){
+        return 1;
+      }else if( iCode>a[iTest] ){
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Delete a "unicode61" tokenizer.
+*/
+static void fts5UnicodeDelete(Fts5Tokenizer *pTok){
+  if( pTok ){
+    Unicode61Tokenizer *p = (Unicode61Tokenizer*)pTok;
+    sqlite3_free(p->aiException);
+    sqlite3_free(p->aFold);
+    sqlite3_free(p);
+  }
+  return;
+}
+
+static int unicodeSetCategories(Unicode61Tokenizer *p, const char *zCat){
+  const char *z = zCat;
+
+  while( *z ){
+    while( *z==' ' || *z=='\t' ) z++;
+    if( *z && sqlite3Fts5UnicodeCatParse(z, p->aCategory) ){
+      return SQLITE_ERROR;
+    }
+    while( *z!=' ' && *z!='\t' && *z!='\0' ) z++;
+  }
+
+  sqlite3Fts5UnicodeAscii(p->aCategory, p->aTokenChar);
+  return SQLITE_OK;
+}
+
+/*
+** Create a "unicode61" tokenizer.
+*/
+static int fts5UnicodeCreate(
+  void *pUnused,
+  const char **azArg, int nArg,
+  Fts5Tokenizer **ppOut
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Unicode61Tokenizer *p = 0;      /* New tokenizer object */
+
+  UNUSED_PARAM(pUnused);
+
+  if( nArg%2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    p = (Unicode61Tokenizer*)sqlite3_malloc(sizeof(Unicode61Tokenizer));
+    if( p ){
+      const char *zCat = "L* N* Co";
+      int i;
+      memset(p, 0, sizeof(Unicode61Tokenizer));
+
+      p->eRemoveDiacritic = FTS5_REMOVE_DIACRITICS_SIMPLE;
+      p->nFold = 64;
+      p->aFold = sqlite3_malloc64(p->nFold * sizeof(char));
+      if( p->aFold==0 ){
+        rc = SQLITE_NOMEM;
+      }
+
+      /* Search for a "categories" argument */
+      for(i=0; rc==SQLITE_OK && i<nArg; i+=2){
+        if( 0==sqlite3_stricmp(azArg[i], "categories") ){
+          zCat = azArg[i+1];
+        }
+      }
+      if( rc==SQLITE_OK ){
+        rc = unicodeSetCategories(p, zCat);
+      }
+
+      for(i=0; rc==SQLITE_OK && i<nArg; i+=2){
+        const char *zArg = azArg[i+1];
+        if( 0==sqlite3_stricmp(azArg[i], "remove_diacritics") ){
+          if( (zArg[0]!='0' && zArg[0]!='1' && zArg[0]!='2') || zArg[1] ){
+            rc = SQLITE_ERROR;
+          }else{
+            p->eRemoveDiacritic = (zArg[0] - '0');
+            assert( p->eRemoveDiacritic==FTS5_REMOVE_DIACRITICS_NONE
+                 || p->eRemoveDiacritic==FTS5_REMOVE_DIACRITICS_SIMPLE
+                 || p->eRemoveDiacritic==FTS5_REMOVE_DIACRITICS_COMPLEX
+            );
+          }
+        }else
+        if( 0==sqlite3_stricmp(azArg[i], "tokenchars") ){
+          rc = fts5UnicodeAddExceptions(p, zArg, 1);
+        }else
+        if( 0==sqlite3_stricmp(azArg[i], "separators") ){
+          rc = fts5UnicodeAddExceptions(p, zArg, 0);
+        }else
+        if( 0==sqlite3_stricmp(azArg[i], "categories") ){
+          /* no-op */
+        }else{
+          rc = SQLITE_ERROR;
+        }
+      }
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+    if( rc!=SQLITE_OK ){
+      fts5UnicodeDelete((Fts5Tokenizer*)p);
+      p = 0;
+    }
+    *ppOut = (Fts5Tokenizer*)p;
+  }
+  return rc;
+}
+
+/*
+** Return true if, for the purposes of tokenizing with the tokenizer
+** passed as the first argument, codepoint iCode is considered a token
+** character (not a separator).
+*/
+static int fts5UnicodeIsAlnum(Unicode61Tokenizer *p, int iCode){
+  return (
+    p->aCategory[sqlite3Fts5UnicodeCategory((u32)iCode)]
+    ^ fts5UnicodeIsException(p, iCode)
+  );
+}
+
+static int fts5UnicodeTokenize(
+  Fts5Tokenizer *pTokenizer,
+  void *pCtx,
+  int iUnused,
+  const char *pText, int nText,
+  int (*xToken)(void*, int, const char*, int nToken, int iStart, int iEnd)
+){
+  Unicode61Tokenizer *p = (Unicode61Tokenizer*)pTokenizer;
+  int rc = SQLITE_OK;
+  unsigned char *a = p->aTokenChar;
+
+  unsigned char *zTerm = (unsigned char*)&pText[nText];
+  unsigned char *zCsr = (unsigned char *)pText;
+
+  /* Output buffer */
+  char *aFold = p->aFold;
+  int nFold = p->nFold;
+  const char *pEnd = &aFold[nFold-6];
+
+  UNUSED_PARAM(iUnused);
+
+  /* Each iteration of this loop gobbles up a contiguous run of separators,
+  ** then the next token.  */
+  while( rc==SQLITE_OK ){
+    u32 iCode;                    /* non-ASCII codepoint read from input */
+    char *zOut = aFold;
+    int is;
+    int ie;
+
+    /* Skip any separator characters. */
+    while( 1 ){
+      if( zCsr>=zTerm ) goto tokenize_done;
+      if( *zCsr & 0x80 ) {
+        /* A character outside of the ascii range. Skip past it if it is
+        ** a separator character. Or break out of the loop if it is not. */
+        is = zCsr - (unsigned char*)pText;
+        READ_UTF8(zCsr, zTerm, iCode);
+        if( fts5UnicodeIsAlnum(p, iCode) ){
+          goto non_ascii_tokenchar;
+        }
+      }else{
+        if( a[*zCsr] ){
+          is = zCsr - (unsigned char*)pText;
+          goto ascii_tokenchar;
+        }
+        zCsr++;
+      }
+    }
+
+    /* Run through the tokenchars. Fold them into the output buffer along
+    ** the way.  */
+    while( zCsr<zTerm ){
+
+      /* Grow the output buffer so that there is sufficient space to fit the
+      ** largest possible utf-8 character.  */
+      if( zOut>pEnd ){
+        aFold = sqlite3_malloc64((sqlite3_int64)nFold*2);
+        if( aFold==0 ){
+          rc = SQLITE_NOMEM;
+          goto tokenize_done;
+        }
+        zOut = &aFold[zOut - p->aFold];
+        memcpy(aFold, p->aFold, nFold);
+        sqlite3_free(p->aFold);
+        p->aFold = aFold;
+        p->nFold = nFold = nFold*2;
+        pEnd = &aFold[nFold-6];
+      }
+
+      if( *zCsr & 0x80 ){
+        /* An non-ascii-range character. Fold it into the output buffer if
+        ** it is a token character, or break out of the loop if it is not. */
+        READ_UTF8(zCsr, zTerm, iCode);
+        if( fts5UnicodeIsAlnum(p,iCode)||sqlite3Fts5UnicodeIsdiacritic(iCode) ){
+ non_ascii_tokenchar:
+          iCode = sqlite3Fts5UnicodeFold(iCode, p->eRemoveDiacritic);
+          if( iCode ) WRITE_UTF8(zOut, iCode);
+        }else{
+          break;
+        }
+      }else if( a[*zCsr]==0 ){
+        /* An ascii-range separator character. End of token. */
+        break;
+      }else{
+ ascii_tokenchar:
+        if( *zCsr>='A' && *zCsr<='Z' ){
+          *zOut++ = *zCsr + 32;
+        }else{
+          *zOut++ = *zCsr;
+        }
+        zCsr++;
+      }
+      ie = zCsr - (unsigned char*)pText;
+    }
+
+    /* Invoke the token callback */
+    rc = xToken(pCtx, 0, aFold, zOut-aFold, is, ie);
+  }
+
+ tokenize_done:
+  if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  return rc;
+}
+
+/**************************************************************************
+** Start of porter stemmer implementation.
+*/
+
+/* Any tokens larger than this (in bytes) are passed through without
+** stemming. */
+#define FTS5_PORTER_MAX_TOKEN 64
+
+typedef struct PorterTokenizer PorterTokenizer;
+struct PorterTokenizer {
+  fts5_tokenizer_v2 tokenizer_v2; /* Parent tokenizer module */
+  Fts5Tokenizer *pTokenizer;      /* Parent tokenizer instance */
+  char aBuf[FTS5_PORTER_MAX_TOKEN + 64];
+};
+
+/*
+** Delete a "porter" tokenizer.
+*/
+static void fts5PorterDelete(Fts5Tokenizer *pTok){
+  if( pTok ){
+    PorterTokenizer *p = (PorterTokenizer*)pTok;
+    if( p->pTokenizer ){
+      p->tokenizer_v2.xDelete(p->pTokenizer);
+    }
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Create a "porter" tokenizer.
+*/
+static int fts5PorterCreate(
+  void *pCtx,
+  const char **azArg, int nArg,
+  Fts5Tokenizer **ppOut
+){
+  fts5_api *pApi = (fts5_api*)pCtx;
+  int rc = SQLITE_OK;
+  PorterTokenizer *pRet;
+  void *pUserdata = 0;
+  const char *zBase = "unicode61";
+  fts5_tokenizer_v2 *pV2 = 0;
+
+  if( nArg>0 ){
+    zBase = azArg[0];
+  }
+
+  pRet = (PorterTokenizer*)sqlite3_malloc(sizeof(PorterTokenizer));
+  if( pRet ){
+    memset(pRet, 0, sizeof(PorterTokenizer));
+    rc = pApi->xFindTokenizer_v2(pApi, zBase, &pUserdata, &pV2);
+  }else{
+    rc = SQLITE_NOMEM;
+  }
+  if( rc==SQLITE_OK ){
+    int nArg2 = (nArg>0 ? nArg-1 : 0);
+    const char **az2 = (nArg2 ? &azArg[1] : 0);
+    memcpy(&pRet->tokenizer_v2, pV2, sizeof(fts5_tokenizer_v2));
+    rc = pRet->tokenizer_v2.xCreate(pUserdata, az2, nArg2, &pRet->pTokenizer);
+  }
+
+  if( rc!=SQLITE_OK ){
+    fts5PorterDelete((Fts5Tokenizer*)pRet);
+    pRet = 0;
+  }
+  *ppOut = (Fts5Tokenizer*)pRet;
+  return rc;
+}
+
+typedef struct PorterContext PorterContext;
+struct PorterContext {
+  void *pCtx;
+  int (*xToken)(void*, int, const char*, int, int, int);
+  char *aBuf;
+};
+
+typedef struct PorterRule PorterRule;
+struct PorterRule {
+  const char *zSuffix;
+  int nSuffix;
+  int (*xCond)(char *zStem, int nStem);
+  const char *zOutput;
+  int nOutput;
+};
+
+#if 0
+static int fts5PorterApply(char *aBuf, int *pnBuf, PorterRule *aRule){
+  int ret = -1;
+  int nBuf = *pnBuf;
+  PorterRule *p;
+
+  for(p=aRule; p->zSuffix; p++){
+    assert( strlen(p->zSuffix)==p->nSuffix );
+    assert( strlen(p->zOutput)==p->nOutput );
+    if( nBuf<p->nSuffix ) continue;
+    if( 0==memcmp(&aBuf[nBuf - p->nSuffix], p->zSuffix, p->nSuffix) ) break;
+  }
+
+  if( p->zSuffix ){
+    int nStem = nBuf - p->nSuffix;
+    if( p->xCond==0 || p->xCond(aBuf, nStem) ){
+      memcpy(&aBuf[nStem], p->zOutput, p->nOutput);
+      *pnBuf = nStem + p->nOutput;
+      ret = p - aRule;
+    }
+  }
+
+  return ret;
+}
+#endif
+
+static int fts5PorterIsVowel(char c, int bYIsVowel){
+  return (
+      c=='a' || c=='e' || c=='i' || c=='o' || c=='u' || (bYIsVowel && c=='y')
+  );
+}
+
+static int fts5PorterGobbleVC(char *zStem, int nStem, int bPrevCons){
+  int i;
+  int bCons = bPrevCons;
+
+  /* Scan for a vowel */
+  for(i=0; i<nStem; i++){
+    if( 0==(bCons = !fts5PorterIsVowel(zStem[i], bCons)) ) break;
+  }
+
+  /* Scan for a consonent */
+  for(i++; i<nStem; i++){
+    if( (bCons = !fts5PorterIsVowel(zStem[i], bCons)) ) return i+1;
+  }
+  return 0;
+}
+
+/* porter rule condition: (m > 0) */
+static int fts5Porter_MGt0(char *zStem, int nStem){
+  return !!fts5PorterGobbleVC(zStem, nStem, 0);
+}
+
+/* porter rule condition: (m > 1) */
+static int fts5Porter_MGt1(char *zStem, int nStem){
+  int n;
+  n = fts5PorterGobbleVC(zStem, nStem, 0);
+  if( n && fts5PorterGobbleVC(&zStem[n], nStem-n, 1) ){
+    return 1;
+  }
+  return 0;
+}
+
+/* porter rule condition: (m = 1) */
+static int fts5Porter_MEq1(char *zStem, int nStem){
+  int n;
+  n = fts5PorterGobbleVC(zStem, nStem, 0);
+  if( n && 0==fts5PorterGobbleVC(&zStem[n], nStem-n, 1) ){
+    return 1;
+  }
+  return 0;
+}
+
+/* porter rule condition: (*o) */
+static int fts5Porter_Ostar(char *zStem, int nStem){
+  if( zStem[nStem-1]=='w' || zStem[nStem-1]=='x' || zStem[nStem-1]=='y' ){
+    return 0;
+  }else{
+    int i;
+    int mask = 0;
+    int bCons = 0;
+    for(i=0; i<nStem; i++){
+      bCons = !fts5PorterIsVowel(zStem[i], bCons);
+      assert( bCons==0 || bCons==1 );
+      mask = (mask << 1) + bCons;
+    }
+    return ((mask & 0x0007)==0x0005);
+  }
+}
+
+/* porter rule condition: (m > 1 and (*S or *T)) */
+static int fts5Porter_MGt1_and_S_or_T(char *zStem, int nStem){
+  assert( nStem>0 );
+  return (zStem[nStem-1]=='s' || zStem[nStem-1]=='t')
+      && fts5Porter_MGt1(zStem, nStem);
+}
+
+/* porter rule condition: (*v*) */
+static int fts5Porter_Vowel(char *zStem, int nStem){
+  int i;
+  for(i=0; i<nStem; i++){
+    if( fts5PorterIsVowel(zStem[i], i>0) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+
+/**************************************************************************
+***************************************************************************
+** GENERATED CODE STARTS HERE (mkportersteps.tcl)
+*/
+
+static int fts5PorterStep4(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'a':
+      if( nBuf>2 && 0==memcmp("al", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+        }
+      }
+      break;
+
+    case 'c':
+      if( nBuf>4 && 0==memcmp("ance", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }else if( nBuf>4 && 0==memcmp("ence", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }
+      break;
+
+    case 'e':
+      if( nBuf>2 && 0==memcmp("er", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+        }
+      }
+      break;
+
+    case 'i':
+      if( nBuf>2 && 0==memcmp("ic", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+        }
+      }
+      break;
+
+    case 'l':
+      if( nBuf>4 && 0==memcmp("able", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }else if( nBuf>4 && 0==memcmp("ible", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }
+      break;
+
+    case 'n':
+      if( nBuf>3 && 0==memcmp("ant", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }else if( nBuf>5 && 0==memcmp("ement", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-5) ){
+          *pnBuf = nBuf - 5;
+        }
+      }else if( nBuf>4 && 0==memcmp("ment", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }else if( nBuf>3 && 0==memcmp("ent", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'o':
+      if( nBuf>3 && 0==memcmp("ion", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1_and_S_or_T(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }else if( nBuf>2 && 0==memcmp("ou", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+        }
+      }
+      break;
+
+    case 's':
+      if( nBuf>3 && 0==memcmp("ism", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 't':
+      if( nBuf>3 && 0==memcmp("ate", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }else if( nBuf>3 && 0==memcmp("iti", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'u':
+      if( nBuf>3 && 0==memcmp("ous", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'v':
+      if( nBuf>3 && 0==memcmp("ive", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'z':
+      if( nBuf>3 && 0==memcmp("ize", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+  }
+  return ret;
+}
+
+
+static int fts5PorterStep1B2(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'a':
+      if( nBuf>2 && 0==memcmp("at", &aBuf[nBuf-2], 2) ){
+        memcpy(&aBuf[nBuf-2], "ate", 3);
+        *pnBuf = nBuf - 2 + 3;
+        ret = 1;
+      }
+      break;
+
+    case 'b':
+      if( nBuf>2 && 0==memcmp("bl", &aBuf[nBuf-2], 2) ){
+        memcpy(&aBuf[nBuf-2], "ble", 3);
+        *pnBuf = nBuf - 2 + 3;
+        ret = 1;
+      }
+      break;
+
+    case 'i':
+      if( nBuf>2 && 0==memcmp("iz", &aBuf[nBuf-2], 2) ){
+        memcpy(&aBuf[nBuf-2], "ize", 3);
+        *pnBuf = nBuf - 2 + 3;
+        ret = 1;
+      }
+      break;
+
+  }
+  return ret;
+}
+
+
+static int fts5PorterStep2(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'a':
+      if( nBuf>7 && 0==memcmp("ational", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ate", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }else if( nBuf>6 && 0==memcmp("tional", &aBuf[nBuf-6], 6) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-6) ){
+          memcpy(&aBuf[nBuf-6], "tion", 4);
+          *pnBuf = nBuf - 6 + 4;
+        }
+      }
+      break;
+
+    case 'c':
+      if( nBuf>4 && 0==memcmp("enci", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ence", 4);
+          *pnBuf = nBuf - 4 + 4;
+        }
+      }else if( nBuf>4 && 0==memcmp("anci", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ance", 4);
+          *pnBuf = nBuf - 4 + 4;
+        }
+      }
+      break;
+
+    case 'e':
+      if( nBuf>4 && 0==memcmp("izer", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ize", 3);
+          *pnBuf = nBuf - 4 + 3;
+        }
+      }
+      break;
+
+    case 'g':
+      if( nBuf>4 && 0==memcmp("logi", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "log", 3);
+          *pnBuf = nBuf - 4 + 3;
+        }
+      }
+      break;
+
+    case 'l':
+      if( nBuf>3 && 0==memcmp("bli", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-3) ){
+          memcpy(&aBuf[nBuf-3], "ble", 3);
+          *pnBuf = nBuf - 3 + 3;
+        }
+      }else if( nBuf>4 && 0==memcmp("alli", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "al", 2);
+          *pnBuf = nBuf - 4 + 2;
+        }
+      }else if( nBuf>5 && 0==memcmp("entli", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ent", 3);
+          *pnBuf = nBuf - 5 + 3;
+        }
+      }else if( nBuf>3 && 0==memcmp("eli", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-3) ){
+          memcpy(&aBuf[nBuf-3], "e", 1);
+          *pnBuf = nBuf - 3 + 1;
+        }
+      }else if( nBuf>5 && 0==memcmp("ousli", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ous", 3);
+          *pnBuf = nBuf - 5 + 3;
+        }
+      }
+      break;
+
+    case 'o':
+      if( nBuf>7 && 0==memcmp("ization", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ize", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }else if( nBuf>5 && 0==memcmp("ation", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ate", 3);
+          *pnBuf = nBuf - 5 + 3;
+        }
+      }else if( nBuf>4 && 0==memcmp("ator", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ate", 3);
+          *pnBuf = nBuf - 4 + 3;
+        }
+      }
+      break;
+
+    case 's':
+      if( nBuf>5 && 0==memcmp("alism", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "al", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }else if( nBuf>7 && 0==memcmp("iveness", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ive", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }else if( nBuf>7 && 0==memcmp("fulness", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ful", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }else if( nBuf>7 && 0==memcmp("ousness", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ous", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }
+      break;
+
+    case 't':
+      if( nBuf>5 && 0==memcmp("aliti", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "al", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }else if( nBuf>5 && 0==memcmp("iviti", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ive", 3);
+          *pnBuf = nBuf - 5 + 3;
+        }
+      }else if( nBuf>6 && 0==memcmp("biliti", &aBuf[nBuf-6], 6) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-6) ){
+          memcpy(&aBuf[nBuf-6], "ble", 3);
+          *pnBuf = nBuf - 6 + 3;
+        }
+      }
+      break;
+
+  }
+  return ret;
+}
+
+
+static int fts5PorterStep3(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'a':
+      if( nBuf>4 && 0==memcmp("ical", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ic", 2);
+          *pnBuf = nBuf - 4 + 2;
+        }
+      }
+      break;
+
+    case 's':
+      if( nBuf>4 && 0==memcmp("ness", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }
+      break;
+
+    case 't':
+      if( nBuf>5 && 0==memcmp("icate", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ic", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }else if( nBuf>5 && 0==memcmp("iciti", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ic", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }
+      break;
+
+    case 'u':
+      if( nBuf>3 && 0==memcmp("ful", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'v':
+      if( nBuf>5 && 0==memcmp("ative", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          *pnBuf = nBuf - 5;
+        }
+      }
+      break;
+
+    case 'z':
+      if( nBuf>5 && 0==memcmp("alize", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "al", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }
+      break;
+
+  }
+  return ret;
+}
+
+
+static int fts5PorterStep1B(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'e':
+      if( nBuf>3 && 0==memcmp("eed", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-3) ){
+          memcpy(&aBuf[nBuf-3], "ee", 2);
+          *pnBuf = nBuf - 3 + 2;
+        }
+      }else if( nBuf>2 && 0==memcmp("ed", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_Vowel(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+          ret = 1;
+        }
+      }
+      break;
+
+    case 'n':
+      if( nBuf>3 && 0==memcmp("ing", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_Vowel(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+          ret = 1;
+        }
+      }
+      break;
+
+  }
+  return ret;
+}
+
+/*
+** GENERATED CODE ENDS HERE (mkportersteps.tcl)
+***************************************************************************
+**************************************************************************/
+
+static void fts5PorterStep1A(char *aBuf, int *pnBuf){
+  int nBuf = *pnBuf;
+  if( aBuf[nBuf-1]=='s' ){
+    if( aBuf[nBuf-2]=='e' ){
+      if( (nBuf>4 && aBuf[nBuf-4]=='s' && aBuf[nBuf-3]=='s')
+       || (nBuf>3 && aBuf[nBuf-3]=='i' )
+      ){
+        *pnBuf = nBuf-2;
+      }else{
+        *pnBuf = nBuf-1;
+      }
+    }
+    else if( aBuf[nBuf-2]!='s' ){
+      *pnBuf = nBuf-1;
+    }
+  }
+}
+
+static int fts5PorterCb(
+  void *pCtx,
+  int tflags,
+  const char *pToken,
+  int nToken,
+  int iStart,
+  int iEnd
+){
+  PorterContext *p = (PorterContext*)pCtx;
+
+  char *aBuf;
+  int nBuf;
+
+  if( nToken>FTS5_PORTER_MAX_TOKEN || nToken<3 ) goto pass_through;
+  aBuf = p->aBuf;
+  nBuf = nToken;
+  memcpy(aBuf, pToken, nBuf);
+
+  /* Step 1. */
+  fts5PorterStep1A(aBuf, &nBuf);
+  if( fts5PorterStep1B(aBuf, &nBuf) ){
+    if( fts5PorterStep1B2(aBuf, &nBuf)==0 ){
+      char c = aBuf[nBuf-1];
+      if( fts5PorterIsVowel(c, 0)==0
+       && c!='l' && c!='s' && c!='z' && c==aBuf[nBuf-2]
+      ){
+        nBuf--;
+      }else if( fts5Porter_MEq1(aBuf, nBuf) && fts5Porter_Ostar(aBuf, nBuf) ){
+        aBuf[nBuf++] = 'e';
+      }
+    }
+  }
+
+  /* Step 1C. */
+  if( aBuf[nBuf-1]=='y' && fts5Porter_Vowel(aBuf, nBuf-1) ){
+    aBuf[nBuf-1] = 'i';
+  }
+
+  /* Steps 2 through 4. */
+  fts5PorterStep2(aBuf, &nBuf);
+  fts5PorterStep3(aBuf, &nBuf);
+  fts5PorterStep4(aBuf, &nBuf);
+
+  /* Step 5a. */
+  assert( nBuf>0 );
+  if( aBuf[nBuf-1]=='e' ){
+    if( fts5Porter_MGt1(aBuf, nBuf-1)
+     || (fts5Porter_MEq1(aBuf, nBuf-1) && !fts5Porter_Ostar(aBuf, nBuf-1))
+    ){
+      nBuf--;
+    }
+  }
+
+  /* Step 5b. */
+  if( nBuf>1 && aBuf[nBuf-1]=='l'
+   && aBuf[nBuf-2]=='l' && fts5Porter_MGt1(aBuf, nBuf-1)
+  ){
+    nBuf--;
+  }
+
+  return p->xToken(p->pCtx, tflags, aBuf, nBuf, iStart, iEnd);
+
+ pass_through:
+  return p->xToken(p->pCtx, tflags, pToken, nToken, iStart, iEnd);
+}
+
+/*
+** Tokenize using the porter tokenizer.
+*/
+static int fts5PorterTokenize(
+  Fts5Tokenizer *pTokenizer,
+  void *pCtx,
+  int flags,
+  const char *pText, int nText,
+  const char *pLoc, int nLoc,
+  int (*xToken)(void*, int, const char*, int nToken, int iStart, int iEnd)
+){
+  PorterTokenizer *p = (PorterTokenizer*)pTokenizer;
+  PorterContext sCtx;
+  sCtx.xToken = xToken;
+  sCtx.pCtx = pCtx;
+  sCtx.aBuf = p->aBuf;
+  return p->tokenizer_v2.xTokenize(
+      p->pTokenizer, (void*)&sCtx, flags, pText, nText, pLoc, nLoc, fts5PorterCb
+  );
+}
+
+/**************************************************************************
+** Start of trigram implementation.
+*/
+typedef struct TrigramTokenizer TrigramTokenizer;
+struct TrigramTokenizer {
+  int bFold;                      /* True to fold to lower-case */
+  int iFoldParam;                 /* Parameter to pass to Fts5UnicodeFold() */
+};
+
+/*
+** Free a trigram tokenizer.
+*/
+static void fts5TriDelete(Fts5Tokenizer *p){
+  sqlite3_free(p);
+}
+
+/*
+** Allocate a trigram tokenizer.
+*/
+static int fts5TriCreate(
+  void *pUnused,
+  const char **azArg,
+  int nArg,
+  Fts5Tokenizer **ppOut
+){
+  int rc = SQLITE_OK;
+  TrigramTokenizer *pNew = 0;
+  UNUSED_PARAM(pUnused);
+  if( nArg%2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    int i;
+    pNew = (TrigramTokenizer*)sqlite3_malloc(sizeof(*pNew));
+    if( pNew==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pNew->bFold = 1;
+      pNew->iFoldParam = 0;
+
+      for(i=0; rc==SQLITE_OK && i<nArg; i+=2){
+        const char *zArg = azArg[i+1];
+        if( 0==sqlite3_stricmp(azArg[i], "case_sensitive") ){
+          if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1] ){
+            rc = SQLITE_ERROR;
+          }else{
+            pNew->bFold = (zArg[0]=='0');
+          }
+        }else if( 0==sqlite3_stricmp(azArg[i], "remove_diacritics") ){
+          if( (zArg[0]!='0' && zArg[0]!='1' && zArg[0]!='2') || zArg[1] ){
+            rc = SQLITE_ERROR;
+          }else{
+            pNew->iFoldParam = (zArg[0]!='0') ? 2 : 0;
+          }
+        }else{
+          rc = SQLITE_ERROR;
+        }
+      }
+
+      if( pNew->iFoldParam!=0 && pNew->bFold==0 ){
+        rc = SQLITE_ERROR;
+      }
+
+      if( rc!=SQLITE_OK ){
+        fts5TriDelete((Fts5Tokenizer*)pNew);
+        pNew = 0;
+      }
+    }
+  }
+  *ppOut = (Fts5Tokenizer*)pNew;
+  return rc;
+}
+
+/*
+** Trigram tokenizer tokenize routine.
+*/
+static int fts5TriTokenize(
+  Fts5Tokenizer *pTok,
+  void *pCtx,
+  int unusedFlags,
+  const char *pText, int nText,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  TrigramTokenizer *p = (TrigramTokenizer*)pTok;
+  int rc = SQLITE_OK;
+  char aBuf[32];
+  char *zOut = aBuf;
+  int ii;
+  const unsigned char *zIn = (const unsigned char*)pText;
+  const unsigned char *zEof = (zIn ? &zIn[nText] : 0);
+  u32 iCode = 0;
+  int aStart[3];                  /* Input offset of each character in aBuf[] */
+
+  UNUSED_PARAM(unusedFlags);
+
+  /* Populate aBuf[] with the characters for the first trigram. */
+  for(ii=0; ii<3; ii++){
+    do {
+      aStart[ii] = zIn - (const unsigned char*)pText;
+      if( zIn>=zEof ) return SQLITE_OK;
+      READ_UTF8(zIn, zEof, iCode);
+      if( p->bFold ) iCode = sqlite3Fts5UnicodeFold(iCode, p->iFoldParam);
+    }while( iCode==0 );
+    WRITE_UTF8(zOut, iCode);
+  }
+
+  /* At the start of each iteration of this loop:
+  **
+  **  aBuf:      Contains 3 characters. The 3 characters of the next trigram.
+  **  zOut:      Points to the byte following the last character in aBuf.
+  **  aStart[3]: Contains the byte offset in the input text corresponding
+  **             to the start of each of the three characters in the buffer.
+  */
+  assert( zIn<=zEof );
+  while( 1 ){
+    int iNext;                    /* Start of character following current tri */
+    const char *z1;
+
+    /* Read characters from the input up until the first non-diacritic */
+    do {
+      iNext = zIn - (const unsigned char*)pText;
+      if( zIn>=zEof ){
+        iCode = 0;
+        break;
+      }
+      READ_UTF8(zIn, zEof, iCode);
+      if( p->bFold ) iCode = sqlite3Fts5UnicodeFold(iCode, p->iFoldParam);
+    }while( iCode==0 );
+
+    /* Pass the current trigram back to fts5 */
+    rc = xToken(pCtx, 0, aBuf, zOut-aBuf, aStart[0], iNext);
+    if( iCode==0 || rc!=SQLITE_OK ) break;
+
+    /* Remove the first character from buffer aBuf[]. Append the character
+    ** with codepoint iCode.  */
+    z1 = aBuf;
+    FTS5_SKIP_UTF8(z1);
+    memmove(aBuf, z1, zOut - z1);
+    zOut -= (z1 - aBuf);
+    WRITE_UTF8(zOut, iCode);
+
+    /* Update the aStart[] array */
+    aStart[0] = aStart[1];
+    aStart[1] = aStart[2];
+    aStart[2] = iNext;
+  }
+
+  return rc;
+}
+
+/*
+** Argument xCreate is a pointer to a constructor function for a tokenizer.
+** pTok is a tokenizer previously created using the same method. This function
+** returns one of FTS5_PATTERN_NONE, FTS5_PATTERN_LIKE or FTS5_PATTERN_GLOB
+** indicating the style of pattern matching that the tokenizer can support.
+** In practice, this is:
+**
+**     "trigram" tokenizer, case_sensitive=1 - FTS5_PATTERN_GLOB
+**     "trigram" tokenizer, case_sensitive=0 (the default) - FTS5_PATTERN_LIKE
+**     all other tokenizers - FTS5_PATTERN_NONE
+*/
+static int sqlite3Fts5TokenizerPattern(
+    int (*xCreate)(void*, const char**, int, Fts5Tokenizer**),
+    Fts5Tokenizer *pTok
+){
+  if( xCreate==fts5TriCreate ){
+    TrigramTokenizer *p = (TrigramTokenizer*)pTok;
+    if( p->iFoldParam==0 ){
+      return p->bFold ? FTS5_PATTERN_LIKE : FTS5_PATTERN_GLOB;
+    }
+  }
+  return FTS5_PATTERN_NONE;
+}
+
+/*
+** Return true if the tokenizer described by p->azArg[] is the trigram
+** tokenizer. This tokenizer needs to be loaded before xBestIndex is
+** called for the first time in order to correctly handle LIKE/GLOB.
+*/
+static int sqlite3Fts5TokenizerPreload(Fts5TokenizerConfig *p){
+  return (p->nArg>=1 && 0==sqlite3_stricmp(p->azArg[0], "trigram"));
+}
+
+
+/*
+** Register all built-in tokenizers with FTS5.
+*/
+static int sqlite3Fts5TokenizerInit(fts5_api *pApi){
+  struct BuiltinTokenizer {
+    const char *zName;
+    fts5_tokenizer x;
+  } aBuiltin[] = {
+    { "unicode61", {fts5UnicodeCreate, fts5UnicodeDelete, fts5UnicodeTokenize}},
+    { "ascii",     {fts5AsciiCreate, fts5AsciiDelete, fts5AsciiTokenize }},
+    { "trigram",   {fts5TriCreate, fts5TriDelete, fts5TriTokenize}},
+  };
+
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* To iterate through builtin functions */
+
+  for(i=0; rc==SQLITE_OK && i<ArraySize(aBuiltin); i++){
+    rc = pApi->xCreateTokenizer(pApi,
+        aBuiltin[i].zName,
+        (void*)pApi,
+        &aBuiltin[i].x,
+        0
+    );
+  }
+  if( rc==SQLITE_OK ){
+    fts5_tokenizer_v2 sPorter = {
+      2,
+      fts5PorterCreate,
+      fts5PorterDelete,
+      fts5PorterTokenize
+    };
+    rc = pApi->xCreateTokenizer_v2(pApi,
+        "porter",
+        (void*)pApi,
+        &sPorter,
+        0
+    );
+  }
+  return rc;
+}
+
+/*
+** 2012-05-25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+/*
+** DO NOT EDIT THIS MACHINE GENERATED FILE.
+*/
+
+
+/* #include <assert.h> */
+
+
+
+/*
+** If the argument is a codepoint corresponding to a lowercase letter
+** in the ASCII range with a diacritic added, return the codepoint
+** of the ASCII letter only. For example, if passed 235 - "LATIN
+** SMALL LETTER E WITH DIAERESIS" - return 65 ("LATIN SMALL LETTER
+** E"). The resuls of passing a codepoint that corresponds to an
+** uppercase letter are undefined.
+*/
+static int fts5_remove_diacritic(int c, int bComplex){
+  unsigned short aDia[] = {
+        0,  1797,  1848,  1859,  1891,  1928,  1940,  1995,
+     2024,  2040,  2060,  2110,  2168,  2206,  2264,  2286,
+     2344,  2383,  2472,  2488,  2516,  2596,  2668,  2732,
+     2782,  2842,  2894,  2954,  2984,  3000,  3028,  3336,
+     3456,  3696,  3712,  3728,  3744,  3766,  3832,  3896,
+     3912,  3928,  3944,  3968,  4008,  4040,  4056,  4106,
+     4138,  4170,  4202,  4234,  4266,  4296,  4312,  4344,
+     4408,  4424,  4442,  4472,  4488,  4504,  6148,  6198,
+     6264,  6280,  6360,  6429,  6505,  6529, 61448, 61468,
+    61512, 61534, 61592, 61610, 61642, 61672, 61688, 61704,
+    61726, 61784, 61800, 61816, 61836, 61880, 61896, 61914,
+    61948, 61998, 62062, 62122, 62154, 62184, 62200, 62218,
+    62252, 62302, 62364, 62410, 62442, 62478, 62536, 62554,
+    62584, 62604, 62640, 62648, 62656, 62664, 62730, 62766,
+    62830, 62890, 62924, 62974, 63032, 63050, 63082, 63118,
+    63182, 63242, 63274, 63310, 63368, 63390,
+  };
+#define HIBIT ((unsigned char)0x80)
+  unsigned char aChar[] = {
+    '\0',      'a',       'c',       'e',       'i',       'n',
+    'o',       'u',       'y',       'y',       'a',       'c',
+    'd',       'e',       'e',       'g',       'h',       'i',
+    'j',       'k',       'l',       'n',       'o',       'r',
+    's',       't',       'u',       'u',       'w',       'y',
+    'z',       'o',       'u',       'a',       'i',       'o',
+    'u',       'u'|HIBIT, 'a'|HIBIT, 'g',       'k',       'o',
+    'o'|HIBIT, 'j',       'g',       'n',       'a'|HIBIT, 'a',
+    'e',       'i',       'o',       'r',       'u',       's',
+    't',       'h',       'a',       'e',       'o'|HIBIT, 'o',
+    'o'|HIBIT, 'y',       '\0',      '\0',      '\0',      '\0',
+    '\0',      '\0',      '\0',      '\0',      'a',       'b',
+    'c'|HIBIT, 'd',       'd',       'e'|HIBIT, 'e',       'e'|HIBIT,
+    'f',       'g',       'h',       'h',       'i',       'i'|HIBIT,
+    'k',       'l',       'l'|HIBIT, 'l',       'm',       'n',
+    'o'|HIBIT, 'p',       'r',       'r'|HIBIT, 'r',       's',
+    's'|HIBIT, 't',       'u',       'u'|HIBIT, 'v',       'w',
+    'w',       'x',       'y',       'z',       'h',       't',
+    'w',       'y',       'a',       'a'|HIBIT, 'a'|HIBIT, 'a'|HIBIT,
+    'e',       'e'|HIBIT, 'e'|HIBIT, 'i',       'o',       'o'|HIBIT,
+    'o'|HIBIT, 'o'|HIBIT, 'u',       'u'|HIBIT, 'u'|HIBIT, 'y',
+  };
+
+  unsigned int key = (((unsigned int)c)<<3) | 0x00000007;
+  int iRes = 0;
+  int iHi = sizeof(aDia)/sizeof(aDia[0]) - 1;
+  int iLo = 0;
+  while( iHi>=iLo ){
+    int iTest = (iHi + iLo) / 2;
+    if( key >= aDia[iTest] ){
+      iRes = iTest;
+      iLo = iTest+1;
+    }else{
+      iHi = iTest-1;
+    }
+  }
+  assert( key>=aDia[iRes] );
+  if( bComplex==0 && (aChar[iRes] & 0x80) ) return c;
+  return (c > (aDia[iRes]>>3) + (aDia[iRes]&0x07)) ? c : ((int)aChar[iRes] & 0x7F);
+}
+
+
+/*
+** Return true if the argument interpreted as a unicode codepoint
+** is a diacritical modifier character.
+*/
+static int sqlite3Fts5UnicodeIsdiacritic(int c){
+  unsigned int mask0 = 0x08029FDF;
+  unsigned int mask1 = 0x000361F8;
+  if( c<768 || c>817 ) return 0;
+  return (c < 768+32) ?
+      (mask0 & ((unsigned int)1 << (c-768))) :
+      (mask1 & ((unsigned int)1 << (c-768-32)));
+}
+
+
+/*
+** Interpret the argument as a unicode codepoint. If the codepoint
+** is an upper case character that has a lower case equivalent,
+** return the codepoint corresponding to the lower case version.
+** Otherwise, return a copy of the argument.
+**
+** The results are undefined if the value passed to this function
+** is less than zero.
+*/
+static int sqlite3Fts5UnicodeFold(int c, int eRemoveDiacritic){
+  /* Each entry in the following array defines a rule for folding a range
+  ** of codepoints to lower case. The rule applies to a range of nRange
+  ** codepoints starting at codepoint iCode.
+  **
+  ** If the least significant bit in flags is clear, then the rule applies
+  ** to all nRange codepoints (i.e. all nRange codepoints are upper case and
+  ** need to be folded). Or, if it is set, then the rule only applies to
+  ** every second codepoint in the range, starting with codepoint C.
+  **
+  ** The 7 most significant bits in flags are an index into the aiOff[]
+  ** array. If a specific codepoint C does require folding, then its lower
+  ** case equivalent is ((C + aiOff[flags>>1]) & 0xFFFF).
+  **
+  ** The contents of this array are generated by parsing the CaseFolding.txt
+  ** file distributed as part of the "Unicode Character Database". See
+  ** http://www.unicode.org for details.
+  */
+  static const struct TableEntry {
+    unsigned short iCode;
+    unsigned char flags;
+    unsigned char nRange;
+  } aEntry[] = {
+    {65, 14, 26},          {181, 64, 1},          {192, 14, 23},
+    {216, 14, 7},          {256, 1, 48},          {306, 1, 6},
+    {313, 1, 16},          {330, 1, 46},          {376, 116, 1},
+    {377, 1, 6},           {383, 104, 1},         {385, 50, 1},
+    {386, 1, 4},           {390, 44, 1},          {391, 0, 1},
+    {393, 42, 2},          {395, 0, 1},           {398, 32, 1},
+    {399, 38, 1},          {400, 40, 1},          {401, 0, 1},
+    {403, 42, 1},          {404, 46, 1},          {406, 52, 1},
+    {407, 48, 1},          {408, 0, 1},           {412, 52, 1},
+    {413, 54, 1},          {415, 56, 1},          {416, 1, 6},
+    {422, 60, 1},          {423, 0, 1},           {425, 60, 1},
+    {428, 0, 1},           {430, 60, 1},          {431, 0, 1},
+    {433, 58, 2},          {435, 1, 4},           {439, 62, 1},
+    {440, 0, 1},           {444, 0, 1},           {452, 2, 1},
+    {453, 0, 1},           {455, 2, 1},           {456, 0, 1},
+    {458, 2, 1},           {459, 1, 18},          {478, 1, 18},
+    {497, 2, 1},           {498, 1, 4},           {502, 122, 1},
+    {503, 134, 1},         {504, 1, 40},          {544, 110, 1},
+    {546, 1, 18},          {570, 70, 1},          {571, 0, 1},
+    {573, 108, 1},         {574, 68, 1},          {577, 0, 1},
+    {579, 106, 1},         {580, 28, 1},          {581, 30, 1},
+    {582, 1, 10},          {837, 36, 1},          {880, 1, 4},
+    {886, 0, 1},           {902, 18, 1},          {904, 16, 3},
+    {908, 26, 1},          {910, 24, 2},          {913, 14, 17},
+    {931, 14, 9},          {962, 0, 1},           {975, 4, 1},
+    {976, 140, 1},         {977, 142, 1},         {981, 146, 1},
+    {982, 144, 1},         {984, 1, 24},          {1008, 136, 1},
+    {1009, 138, 1},        {1012, 130, 1},        {1013, 128, 1},
+    {1015, 0, 1},          {1017, 152, 1},        {1018, 0, 1},
+    {1021, 110, 3},        {1024, 34, 16},        {1040, 14, 32},
+    {1120, 1, 34},         {1162, 1, 54},         {1216, 6, 1},
+    {1217, 1, 14},         {1232, 1, 88},         {1329, 22, 38},
+    {4256, 66, 38},        {4295, 66, 1},         {4301, 66, 1},
+    {7680, 1, 150},        {7835, 132, 1},        {7838, 96, 1},
+    {7840, 1, 96},         {7944, 150, 8},        {7960, 150, 6},
+    {7976, 150, 8},        {7992, 150, 8},        {8008, 150, 6},
+    {8025, 151, 8},        {8040, 150, 8},        {8072, 150, 8},
+    {8088, 150, 8},        {8104, 150, 8},        {8120, 150, 2},
+    {8122, 126, 2},        {8124, 148, 1},        {8126, 100, 1},
+    {8136, 124, 4},        {8140, 148, 1},        {8152, 150, 2},
+    {8154, 120, 2},        {8168, 150, 2},        {8170, 118, 2},
+    {8172, 152, 1},        {8184, 112, 2},        {8186, 114, 2},
+    {8188, 148, 1},        {8486, 98, 1},         {8490, 92, 1},
+    {8491, 94, 1},         {8498, 12, 1},         {8544, 8, 16},
+    {8579, 0, 1},          {9398, 10, 26},        {11264, 22, 47},
+    {11360, 0, 1},         {11362, 88, 1},        {11363, 102, 1},
+    {11364, 90, 1},        {11367, 1, 6},         {11373, 84, 1},
+    {11374, 86, 1},        {11375, 80, 1},        {11376, 82, 1},
+    {11378, 0, 1},         {11381, 0, 1},         {11390, 78, 2},
+    {11392, 1, 100},       {11499, 1, 4},         {11506, 0, 1},
+    {42560, 1, 46},        {42624, 1, 24},        {42786, 1, 14},
+    {42802, 1, 62},        {42873, 1, 4},         {42877, 76, 1},
+    {42878, 1, 10},        {42891, 0, 1},         {42893, 74, 1},
+    {42896, 1, 4},         {42912, 1, 10},        {42922, 72, 1},
+    {65313, 14, 26},
+  };
+  static const unsigned short aiOff[] = {
+   1,     2,     8,     15,    16,    26,    28,    32,
+   37,    38,    40,    48,    63,    64,    69,    71,
+   79,    80,    116,   202,   203,   205,   206,   207,
+   209,   210,   211,   213,   214,   217,   218,   219,
+   775,   7264,  10792, 10795, 23228, 23256, 30204, 54721,
+   54753, 54754, 54756, 54787, 54793, 54809, 57153, 57274,
+   57921, 58019, 58363, 61722, 65268, 65341, 65373, 65406,
+   65408, 65410, 65415, 65424, 65436, 65439, 65450, 65462,
+   65472, 65476, 65478, 65480, 65482, 65488, 65506, 65511,
+   65514, 65521, 65527, 65528, 65529,
+  };
+
+  int ret = c;
+
+  assert( sizeof(unsigned short)==2 && sizeof(unsigned char)==1 );
+
+  if( c<128 ){
+    if( c>='A' && c<='Z' ) ret = c + ('a' - 'A');
+  }else if( c<65536 ){
+    const struct TableEntry *p;
+    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
+    int iLo = 0;
+    int iRes = -1;
+
+    assert( c>aEntry[0].iCode );
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      int cmp = (c - aEntry[iTest].iCode);
+      if( cmp>=0 ){
+        iRes = iTest;
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+
+    assert( iRes>=0 && c>=aEntry[iRes].iCode );
+    p = &aEntry[iRes];
+    if( c<(p->iCode + p->nRange) && 0==(0x01 & p->flags & (p->iCode ^ c)) ){
+      ret = (c + (aiOff[p->flags>>1])) & 0x0000FFFF;
+      assert( ret>0 );
+    }
+
+    if( eRemoveDiacritic ){
+      ret = fts5_remove_diacritic(ret, eRemoveDiacritic==2);
+    }
+  }
+
+  else if( c>=66560 && c<66600 ){
+    ret = c + 40;
+  }
+
+  return ret;
+}
+
+
+static int sqlite3Fts5UnicodeCatParse(const char *zCat, u8 *aArray){
+  aArray[0] = 1;
+  switch( zCat[0] ){
+    case 'C':
+          switch( zCat[1] ){
+            case 'c': aArray[1] = 1; break;
+            case 'f': aArray[2] = 1; break;
+            case 'n': aArray[3] = 1; break;
+            case 's': aArray[4] = 1; break;
+            case 'o': aArray[31] = 1; break;
+            case '*':
+              aArray[1] = 1;
+              aArray[2] = 1;
+              aArray[3] = 1;
+              aArray[4] = 1;
+              aArray[31] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'L':
+          switch( zCat[1] ){
+            case 'l': aArray[5] = 1; break;
+            case 'm': aArray[6] = 1; break;
+            case 'o': aArray[7] = 1; break;
+            case 't': aArray[8] = 1; break;
+            case 'u': aArray[9] = 1; break;
+            case 'C': aArray[30] = 1; break;
+            case '*':
+              aArray[5] = 1;
+              aArray[6] = 1;
+              aArray[7] = 1;
+              aArray[8] = 1;
+              aArray[9] = 1;
+              aArray[30] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'M':
+          switch( zCat[1] ){
+            case 'c': aArray[10] = 1; break;
+            case 'e': aArray[11] = 1; break;
+            case 'n': aArray[12] = 1; break;
+            case '*':
+              aArray[10] = 1;
+              aArray[11] = 1;
+              aArray[12] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'N':
+          switch( zCat[1] ){
+            case 'd': aArray[13] = 1; break;
+            case 'l': aArray[14] = 1; break;
+            case 'o': aArray[15] = 1; break;
+            case '*':
+              aArray[13] = 1;
+              aArray[14] = 1;
+              aArray[15] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'P':
+          switch( zCat[1] ){
+            case 'c': aArray[16] = 1; break;
+            case 'd': aArray[17] = 1; break;
+            case 'e': aArray[18] = 1; break;
+            case 'f': aArray[19] = 1; break;
+            case 'i': aArray[20] = 1; break;
+            case 'o': aArray[21] = 1; break;
+            case 's': aArray[22] = 1; break;
+            case '*':
+              aArray[16] = 1;
+              aArray[17] = 1;
+              aArray[18] = 1;
+              aArray[19] = 1;
+              aArray[20] = 1;
+              aArray[21] = 1;
+              aArray[22] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'S':
+          switch( zCat[1] ){
+            case 'c': aArray[23] = 1; break;
+            case 'k': aArray[24] = 1; break;
+            case 'm': aArray[25] = 1; break;
+            case 'o': aArray[26] = 1; break;
+            case '*':
+              aArray[23] = 1;
+              aArray[24] = 1;
+              aArray[25] = 1;
+              aArray[26] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'Z':
+          switch( zCat[1] ){
+            case 'l': aArray[27] = 1; break;
+            case 'p': aArray[28] = 1; break;
+            case 's': aArray[29] = 1; break;
+            case '*':
+              aArray[27] = 1;
+              aArray[28] = 1;
+              aArray[29] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+
+    default:
+      return 1;
+  }
+  return 0;
+}
+
+static u16 aFts5UnicodeBlock[] = {
+    0,     1471,  1753,  1760,  1760,  1760,  1760,  1760,  1760,  1760,
+    1760,  1760,  1760,  1760,  1760,  1763,  1765,
+  };
+static u16 aFts5UnicodeMap[] = {
+    0,     32,    33,    36,    37,    40,    41,    42,    43,    44,
+    45,    46,    48,    58,    60,    63,    65,    91,    92,    93,
+    94,    95,    96,    97,    123,   124,   125,   126,   127,   160,
+    161,   162,   166,   167,   168,   169,   170,   171,   172,   173,
+    174,   175,   176,   177,   178,   180,   181,   182,   184,   185,
+    186,   187,   188,   191,   192,   215,   216,   223,   247,   248,
+    256,   312,   313,   329,   330,   377,   383,   385,   387,   388,
+    391,   394,   396,   398,   402,   403,   405,   406,   409,   412,
+    414,   415,   417,   418,   423,   427,   428,   431,   434,   436,
+    437,   440,   442,   443,   444,   446,   448,   452,   453,   454,
+    455,   456,   457,   458,   459,   460,   461,   477,   478,   496,
+    497,   498,   499,   500,   503,   505,   506,   564,   570,   572,
+    573,   575,   577,   580,   583,   584,   592,   660,   661,   688,
+    706,   710,   722,   736,   741,   748,   749,   750,   751,   768,
+    880,   884,   885,   886,   890,   891,   894,   900,   902,   903,
+    904,   908,   910,   912,   913,   931,   940,   975,   977,   978,
+    981,   984,   1008,  1012,  1014,  1015,  1018,  1020,  1021,  1072,
+    1120,  1154,  1155,  1160,  1162,  1217,  1231,  1232,  1329,  1369,
+    1370,  1377,  1417,  1418,  1423,  1425,  1470,  1471,  1472,  1473,
+    1475,  1476,  1478,  1479,  1488,  1520,  1523,  1536,  1542,  1545,
+    1547,  1548,  1550,  1552,  1563,  1566,  1568,  1600,  1601,  1611,
+    1632,  1642,  1646,  1648,  1649,  1748,  1749,  1750,  1757,  1758,
+    1759,  1765,  1767,  1769,  1770,  1774,  1776,  1786,  1789,  1791,
+    1792,  1807,  1808,  1809,  1810,  1840,  1869,  1958,  1969,  1984,
+    1994,  2027,  2036,  2038,  2039,  2042,  2048,  2070,  2074,  2075,
+    2084,  2085,  2088,  2089,  2096,  2112,  2137,  2142,  2208,  2210,
+    2276,  2304,  2307,  2308,  2362,  2363,  2364,  2365,  2366,  2369,
+    2377,  2381,  2382,  2384,  2385,  2392,  2402,  2404,  2406,  2416,
+    2417,  2418,  2425,  2433,  2434,  2437,  2447,  2451,  2474,  2482,
+    2486,  2492,  2493,  2494,  2497,  2503,  2507,  2509,  2510,  2519,
+    2524,  2527,  2530,  2534,  2544,  2546,  2548,  2554,  2555,  2561,
+    2563,  2565,  2575,  2579,  2602,  2610,  2613,  2616,  2620,  2622,
+    2625,  2631,  2635,  2641,  2649,  2654,  2662,  2672,  2674,  2677,
+    2689,  2691,  2693,  2703,  2707,  2730,  2738,  2741,  2748,  2749,
+    2750,  2753,  2759,  2761,  2763,  2765,  2768,  2784,  2786,  2790,
+    2800,  2801,  2817,  2818,  2821,  2831,  2835,  2858,  2866,  2869,
+    2876,  2877,  2878,  2879,  2880,  2881,  2887,  2891,  2893,  2902,
+    2903,  2908,  2911,  2914,  2918,  2928,  2929,  2930,  2946,  2947,
+    2949,  2958,  2962,  2969,  2972,  2974,  2979,  2984,  2990,  3006,
+    3008,  3009,  3014,  3018,  3021,  3024,  3031,  3046,  3056,  3059,
+    3065,  3066,  3073,  3077,  3086,  3090,  3114,  3125,  3133,  3134,
+    3137,  3142,  3146,  3157,  3160,  3168,  3170,  3174,  3192,  3199,
+    3202,  3205,  3214,  3218,  3242,  3253,  3260,  3261,  3262,  3263,
+    3264,  3270,  3271,  3274,  3276,  3285,  3294,  3296,  3298,  3302,
+    3313,  3330,  3333,  3342,  3346,  3389,  3390,  3393,  3398,  3402,
+    3405,  3406,  3415,  3424,  3426,  3430,  3440,  3449,  3450,  3458,
+    3461,  3482,  3507,  3517,  3520,  3530,  3535,  3538,  3542,  3544,
+    3570,  3572,  3585,  3633,  3634,  3636,  3647,  3648,  3654,  3655,
+    3663,  3664,  3674,  3713,  3716,  3719,  3722,  3725,  3732,  3737,
+    3745,  3749,  3751,  3754,  3757,  3761,  3762,  3764,  3771,  3773,
+    3776,  3782,  3784,  3792,  3804,  3840,  3841,  3844,  3859,  3860,
+    3861,  3864,  3866,  3872,  3882,  3892,  3893,  3894,  3895,  3896,
+    3897,  3898,  3899,  3900,  3901,  3902,  3904,  3913,  3953,  3967,
+    3968,  3973,  3974,  3976,  3981,  3993,  4030,  4038,  4039,  4046,
+    4048,  4053,  4057,  4096,  4139,  4141,  4145,  4146,  4152,  4153,
+    4155,  4157,  4159,  4160,  4170,  4176,  4182,  4184,  4186,  4190,
+    4193,  4194,  4197,  4199,  4206,  4209,  4213,  4226,  4227,  4229,
+    4231,  4237,  4238,  4239,  4240,  4250,  4253,  4254,  4256,  4295,
+    4301,  4304,  4347,  4348,  4349,  4682,  4688,  4696,  4698,  4704,
+    4746,  4752,  4786,  4792,  4800,  4802,  4808,  4824,  4882,  4888,
+    4957,  4960,  4969,  4992,  5008,  5024,  5120,  5121,  5741,  5743,
+    5760,  5761,  5787,  5788,  5792,  5867,  5870,  5888,  5902,  5906,
+    5920,  5938,  5941,  5952,  5970,  5984,  5998,  6002,  6016,  6068,
+    6070,  6071,  6078,  6086,  6087,  6089,  6100,  6103,  6104,  6107,
+    6108,  6109,  6112,  6128,  6144,  6150,  6151,  6155,  6158,  6160,
+    6176,  6211,  6212,  6272,  6313,  6314,  6320,  6400,  6432,  6435,
+    6439,  6441,  6448,  6450,  6451,  6457,  6464,  6468,  6470,  6480,
+    6512,  6528,  6576,  6593,  6600,  6608,  6618,  6622,  6656,  6679,
+    6681,  6686,  6688,  6741,  6742,  6743,  6744,  6752,  6753,  6754,
+    6755,  6757,  6765,  6771,  6783,  6784,  6800,  6816,  6823,  6824,
+    6912,  6916,  6917,  6964,  6965,  6966,  6971,  6972,  6973,  6978,
+    6979,  6981,  6992,  7002,  7009,  7019,  7028,  7040,  7042,  7043,
+    7073,  7074,  7078,  7080,  7082,  7083,  7084,  7086,  7088,  7098,
+    7142,  7143,  7144,  7146,  7149,  7150,  7151,  7154,  7164,  7168,
+    7204,  7212,  7220,  7222,  7227,  7232,  7245,  7248,  7258,  7288,
+    7294,  7360,  7376,  7379,  7380,  7393,  7394,  7401,  7405,  7406,
+    7410,  7412,  7413,  7424,  7468,  7531,  7544,  7545,  7579,  7616,
+    7676,  7680,  7830,  7838,  7936,  7944,  7952,  7960,  7968,  7976,
+    7984,  7992,  8000,  8008,  8016,  8025,  8027,  8029,  8031,  8033,
+    8040,  8048,  8064,  8072,  8080,  8088,  8096,  8104,  8112,  8118,
+    8120,  8124,  8125,  8126,  8127,  8130,  8134,  8136,  8140,  8141,
+    8144,  8150,  8152,  8157,  8160,  8168,  8173,  8178,  8182,  8184,
+    8188,  8189,  8192,  8203,  8208,  8214,  8216,  8217,  8218,  8219,
+    8221,  8222,  8223,  8224,  8232,  8233,  8234,  8239,  8240,  8249,
+    8250,  8251,  8255,  8257,  8260,  8261,  8262,  8263,  8274,  8275,
+    8276,  8277,  8287,  8288,  8298,  8304,  8305,  8308,  8314,  8317,
+    8318,  8319,  8320,  8330,  8333,  8334,  8336,  8352,  8400,  8413,
+    8417,  8418,  8421,  8448,  8450,  8451,  8455,  8456,  8458,  8459,
+    8462,  8464,  8467,  8468,  8469,  8470,  8472,  8473,  8478,  8484,
+    8485,  8486,  8487,  8488,  8489,  8490,  8494,  8495,  8496,  8500,
+    8501,  8505,  8506,  8508,  8510,  8512,  8517,  8519,  8522,  8523,
+    8524,  8526,  8527,  8528,  8544,  8579,  8581,  8585,  8592,  8597,
+    8602,  8604,  8608,  8609,  8611,  8612,  8614,  8615,  8622,  8623,
+    8654,  8656,  8658,  8659,  8660,  8661,  8692,  8960,  8968,  8972,
+    8992,  8994,  9001,  9002,  9003,  9084,  9085,  9115,  9140,  9180,
+    9186,  9216,  9280,  9312,  9372,  9450,  9472,  9655,  9656,  9665,
+    9666,  9720,  9728,  9839,  9840,  9985,  10088, 10089, 10090, 10091,
+    10092, 10093, 10094, 10095, 10096, 10097, 10098, 10099, 10100, 10101,
+    10102, 10132, 10176, 10181, 10182, 10183, 10214, 10215, 10216, 10217,
+    10218, 10219, 10220, 10221, 10222, 10223, 10224, 10240, 10496, 10627,
+    10628, 10629, 10630, 10631, 10632, 10633, 10634, 10635, 10636, 10637,
+    10638, 10639, 10640, 10641, 10642, 10643, 10644, 10645, 10646, 10647,
+    10648, 10649, 10712, 10713, 10714, 10715, 10716, 10748, 10749, 10750,
+    11008, 11056, 11077, 11079, 11088, 11264, 11312, 11360, 11363, 11365,
+    11367, 11374, 11377, 11378, 11380, 11381, 11383, 11388, 11390, 11393,
+    11394, 11492, 11493, 11499, 11503, 11506, 11513, 11517, 11518, 11520,
+    11559, 11565, 11568, 11631, 11632, 11647, 11648, 11680, 11688, 11696,
+    11704, 11712, 11720, 11728, 11736, 11744, 11776, 11778, 11779, 11780,
+    11781, 11782, 11785, 11786, 11787, 11788, 11789, 11790, 11799, 11800,
+    11802, 11803, 11804, 11805, 11806, 11808, 11809, 11810, 11811, 11812,
+    11813, 11814, 11815, 11816, 11817, 11818, 11823, 11824, 11834, 11904,
+    11931, 12032, 12272, 12288, 12289, 12292, 12293, 12294, 12295, 12296,
+    12297, 12298, 12299, 12300, 12301, 12302, 12303, 12304, 12305, 12306,
+    12308, 12309, 12310, 12311, 12312, 12313, 12314, 12315, 12316, 12317,
+    12318, 12320, 12321, 12330, 12334, 12336, 12337, 12342, 12344, 12347,
+    12348, 12349, 12350, 12353, 12441, 12443, 12445, 12447, 12448, 12449,
+    12539, 12540, 12543, 12549, 12593, 12688, 12690, 12694, 12704, 12736,
+    12784, 12800, 12832, 12842, 12872, 12880, 12881, 12896, 12928, 12938,
+    12977, 12992, 13056, 13312, 19893, 19904, 19968, 40908, 40960, 40981,
+    40982, 42128, 42192, 42232, 42238, 42240, 42508, 42509, 42512, 42528,
+    42538, 42560, 42606, 42607, 42608, 42611, 42612, 42622, 42623, 42624,
+    42655, 42656, 42726, 42736, 42738, 42752, 42775, 42784, 42786, 42800,
+    42802, 42864, 42865, 42873, 42878, 42888, 42889, 42891, 42896, 42912,
+    43000, 43002, 43003, 43010, 43011, 43014, 43015, 43019, 43020, 43043,
+    43045, 43047, 43048, 43056, 43062, 43064, 43065, 43072, 43124, 43136,
+    43138, 43188, 43204, 43214, 43216, 43232, 43250, 43256, 43259, 43264,
+    43274, 43302, 43310, 43312, 43335, 43346, 43359, 43360, 43392, 43395,
+    43396, 43443, 43444, 43446, 43450, 43452, 43453, 43457, 43471, 43472,
+    43486, 43520, 43561, 43567, 43569, 43571, 43573, 43584, 43587, 43588,
+    43596, 43597, 43600, 43612, 43616, 43632, 43633, 43639, 43642, 43643,
+    43648, 43696, 43697, 43698, 43701, 43703, 43705, 43710, 43712, 43713,
+    43714, 43739, 43741, 43742, 43744, 43755, 43756, 43758, 43760, 43762,
+    43763, 43765, 43766, 43777, 43785, 43793, 43808, 43816, 43968, 44003,
+    44005, 44006, 44008, 44009, 44011, 44012, 44013, 44016, 44032, 55203,
+    55216, 55243, 55296, 56191, 56319, 57343, 57344, 63743, 63744, 64112,
+    64256, 64275, 64285, 64286, 64287, 64297, 64298, 64312, 64318, 64320,
+    64323, 64326, 64434, 64467, 64830, 64831, 64848, 64914, 65008, 65020,
+    65021, 65024, 65040, 65047, 65048, 65049, 65056, 65072, 65073, 65075,
+    65077, 65078, 65079, 65080, 65081, 65082, 65083, 65084, 65085, 65086,
+    65087, 65088, 65089, 65090, 65091, 65092, 65093, 65095, 65096, 65097,
+    65101, 65104, 65108, 65112, 65113, 65114, 65115, 65116, 65117, 65118,
+    65119, 65122, 65123, 65124, 65128, 65129, 65130, 65136, 65142, 65279,
+    65281, 65284, 65285, 65288, 65289, 65290, 65291, 65292, 65293, 65294,
+    65296, 65306, 65308, 65311, 65313, 65339, 65340, 65341, 65342, 65343,
+    65344, 65345, 65371, 65372, 65373, 65374, 65375, 65376, 65377, 65378,
+    65379, 65380, 65382, 65392, 65393, 65438, 65440, 65474, 65482, 65490,
+    65498, 65504, 65506, 65507, 65508, 65509, 65512, 65513, 65517, 65529,
+    65532, 0,     13,    40,    60,    63,    80,    128,   256,   263,
+    311,   320,   373,   377,   394,   400,   464,   509,   640,   672,
+    768,   800,   816,   833,   834,   842,   896,   927,   928,   968,
+    976,   977,   1024,  1064,  1104,  1184,  2048,  2056,  2058,  2103,
+    2108,  2111,  2135,  2136,  2304,  2326,  2335,  2336,  2367,  2432,
+    2494,  2560,  2561,  2565,  2572,  2576,  2581,  2585,  2616,  2623,
+    2624,  2640,  2656,  2685,  2687,  2816,  2873,  2880,  2904,  2912,
+    2936,  3072,  3680,  4096,  4097,  4098,  4099,  4152,  4167,  4178,
+    4198,  4224,  4226,  4227,  4272,  4275,  4279,  4281,  4283,  4285,
+    4286,  4304,  4336,  4352,  4355,  4391,  4396,  4397,  4406,  4416,
+    4480,  4482,  4483,  4531,  4534,  4543,  4545,  4549,  4560,  5760,
+    5803,  5804,  5805,  5806,  5808,  5814,  5815,  5824,  8192,  9216,
+    9328,  12288, 26624, 28416, 28496, 28497, 28559, 28563, 45056, 53248,
+    53504, 53545, 53605, 53607, 53610, 53613, 53619, 53627, 53635, 53637,
+    53644, 53674, 53678, 53760, 53826, 53829, 54016, 54112, 54272, 54298,
+    54324, 54350, 54358, 54376, 54402, 54428, 54430, 54434, 54437, 54441,
+    54446, 54454, 54459, 54461, 54469, 54480, 54506, 54532, 54535, 54541,
+    54550, 54558, 54584, 54587, 54592, 54598, 54602, 54610, 54636, 54662,
+    54688, 54714, 54740, 54766, 54792, 54818, 54844, 54870, 54896, 54922,
+    54952, 54977, 54978, 55003, 55004, 55010, 55035, 55036, 55061, 55062,
+    55068, 55093, 55094, 55119, 55120, 55126, 55151, 55152, 55177, 55178,
+    55184, 55209, 55210, 55235, 55236, 55242, 55246, 60928, 60933, 60961,
+    60964, 60967, 60969, 60980, 60985, 60987, 60994, 60999, 61001, 61003,
+    61005, 61009, 61012, 61015, 61017, 61019, 61021, 61023, 61025, 61028,
+    61031, 61036, 61044, 61049, 61054, 61056, 61067, 61089, 61093, 61099,
+    61168, 61440, 61488, 61600, 61617, 61633, 61649, 61696, 61712, 61744,
+    61808, 61926, 61968, 62016, 62032, 62208, 62256, 62263, 62336, 62368,
+    62406, 62432, 62464, 62528, 62530, 62713, 62720, 62784, 62800, 62971,
+    63045, 63104, 63232, 0,     42710, 42752, 46900, 46912, 47133, 63488,
+    1,     32,    256,   0,     65533,
+  };
+static u16 aFts5UnicodeData[] = {
+    1025,  61,    117,   55,    117,   54,    50,    53,    57,    53,
+    49,    85,    333,   85,    121,   85,    841,   54,    53,    50,
+    56,    48,    56,    837,   54,    57,    50,    57,    1057,  61,
+    53,    151,   58,    53,    56,    58,    39,    52,    57,    34,
+    58,    56,    58,    57,    79,    56,    37,    85,    56,    47,
+    39,    51,    111,   53,    745,   57,    233,   773,   57,    261,
+    1822,  37,    542,   37,    1534,  222,   69,    73,    37,    126,
+    126,   73,    69,    137,   37,    73,    37,    105,   101,   73,
+    37,    73,    37,    190,   158,   37,    126,   126,   73,    37,
+    126,   94,    37,    39,    94,    69,    135,   41,    40,    37,
+    41,    40,    37,    41,    40,    37,    542,   37,    606,   37,
+    41,    40,    37,    126,   73,    37,    1886,  197,   73,    37,
+    73,    69,    126,   105,   37,    286,   2181,  39,    869,   582,
+    152,   390,   472,   166,   248,   38,    56,    38,    568,   3596,
+    158,   38,    56,    94,    38,    101,   53,    88,    41,    53,
+    105,   41,    73,    37,    553,   297,   1125,  94,    37,    105,
+    101,   798,   133,   94,    57,    126,   94,    37,    1641,  1541,
+    1118,  58,    172,   75,    1790,  478,   37,    2846,  1225,  38,
+    213,   1253,  53,    49,    55,    1452,  49,    44,    53,    76,
+    53,    76,    53,    44,    871,   103,   85,    162,   121,   85,
+    55,    85,    90,    364,   53,    85,    1031,  38,    327,   684,
+    333,   149,   71,    44,    3175,  53,    39,    236,   34,    58,
+    204,   70,    76,    58,    140,   71,    333,   103,   90,    39,
+    469,   34,    39,    44,    967,   876,   2855,  364,   39,    333,
+    1063,  300,   70,    58,    117,   38,    711,   140,   38,    300,
+    38,    108,   38,    172,   501,   807,   108,   53,    39,    359,
+    876,   108,   42,    1735,  44,    42,    44,    39,    106,   268,
+    138,   44,    74,    39,    236,   327,   76,    85,    333,   53,
+    38,    199,   231,   44,    74,    263,   71,    711,   231,   39,
+    135,   44,    39,    106,   140,   74,    74,    44,    39,    42,
+    71,    103,   76,    333,   71,    87,    207,   58,    55,    76,
+    42,    199,   71,    711,   231,   71,    71,    71,    44,    106,
+    76,    76,    108,   44,    135,   39,    333,   76,    103,   44,
+    76,    42,    295,   103,   711,   231,   71,    167,   44,    39,
+    106,   172,   76,    42,    74,    44,    39,    71,    76,    333,
+    53,    55,    44,    74,    263,   71,    711,   231,   71,    167,
+    44,    39,    42,    44,    42,    140,   74,    74,    44,    44,
+    42,    71,    103,   76,    333,   58,    39,    207,   44,    39,
+    199,   103,   135,   71,    39,    71,    71,    103,   391,   74,
+    44,    74,    106,   106,   44,    39,    42,    333,   111,   218,
+    55,    58,    106,   263,   103,   743,   327,   167,   39,    108,
+    138,   108,   140,   76,    71,    71,    76,    333,   239,   58,
+    74,    263,   103,   743,   327,   167,   44,    39,    42,    44,
+    170,   44,    74,    74,    76,    74,    39,    71,    76,    333,
+    71,    74,    263,   103,   1319,  39,    106,   140,   106,   106,
+    44,    39,    42,    71,    76,    333,   207,   58,    199,   74,
+    583,   775,   295,   39,    231,   44,    106,   108,   44,    266,
+    74,    53,    1543,  44,    71,    236,   55,    199,   38,    268,
+    53,    333,   85,    71,    39,    71,    39,    39,    135,   231,
+    103,   39,    39,    71,    135,   44,    71,    204,   76,    39,
+    167,   38,    204,   333,   135,   39,    122,   501,   58,    53,
+    122,   76,    218,   333,   335,   58,    44,    58,    44,    58,
+    44,    54,    50,    54,    50,    74,    263,   1159,  460,   42,
+    172,   53,    76,    167,   364,   1164,  282,   44,    218,   90,
+    181,   154,   85,    1383,  74,    140,   42,    204,   42,    76,
+    74,    76,    39,    333,   213,   199,   74,    76,    135,   108,
+    39,    106,   71,    234,   103,   140,   423,   44,    74,    76,
+    202,   44,    39,    42,    333,   106,   44,    90,    1225,  41,
+    41,    1383,  53,    38,    10631, 135,   231,   39,    135,   1319,
+    135,   1063,  135,   231,   39,    135,   487,   1831,  135,   2151,
+    108,   309,   655,   519,   346,   2727,  49,    19847, 85,    551,
+    61,    839,   54,    50,    2407,  117,   110,   423,   135,   108,
+    583,   108,   85,    583,   76,    423,   103,   76,    1671,  76,
+    42,    236,   266,   44,    74,    364,   117,   38,    117,   55,
+    39,    44,    333,   335,   213,   49,    149,   108,   61,    333,
+    1127,  38,    1671,  1319,  44,    39,    2247,  935,   108,   138,
+    76,    106,   74,    44,    202,   108,   58,    85,    333,   967,
+    167,   1415,  554,   231,   74,    333,   47,    1114,  743,   76,
+    106,   85,    1703,  42,    44,    42,    236,   44,    42,    44,
+    74,    268,   202,   332,   44,    333,   333,   245,   38,    213,
+    140,   42,    1511,  44,    42,    172,   42,    44,    170,   44,
+    74,    231,   333,   245,   346,   300,   314,   76,    42,    967,
+    42,    140,   74,    76,    42,    44,    74,    71,    333,   1415,
+    44,    42,    76,    106,   44,    42,    108,   74,    149,   1159,
+    266,   268,   74,    76,    181,   333,   103,   333,   967,   198,
+    85,    277,   108,   53,    428,   42,    236,   135,   44,    135,
+    74,    44,    71,    1413,  2022,  421,   38,    1093,  1190,  1260,
+    140,   4830,  261,   3166,  261,   265,   197,   201,   261,   265,
+    261,   265,   197,   201,   261,   41,    41,    41,    94,    229,
+    265,   453,   261,   264,   261,   264,   261,   264,   165,   69,
+    137,   40,    56,    37,    120,   101,   69,    137,   40,    120,
+    133,   69,    137,   120,   261,   169,   120,   101,   69,    137,
+    40,    88,    381,   162,   209,   85,    52,    51,    54,    84,
+    51,    54,    52,    277,   59,    60,    162,   61,    309,   52,
+    51,    149,   80,    117,   57,    54,    50,    373,   57,    53,
+    48,    341,   61,    162,   194,   47,    38,    207,   121,   54,
+    50,    38,    335,   121,   54,    50,    422,   855,   428,   139,
+    44,    107,   396,   90,    41,    154,   41,    90,    37,    105,
+    69,    105,   37,    58,    41,    90,    57,    169,   218,   41,
+    58,    41,    58,    41,    58,    137,   58,    37,    137,   37,
+    135,   37,    90,    69,    73,    185,   94,    101,   58,    57,
+    90,    37,    58,    527,   1134,  94,    142,   47,    185,   186,
+    89,    154,   57,    90,    57,    90,    57,    250,   57,    1018,
+    89,    90,    57,    58,    57,    1018,  8601,  282,   153,   666,
+    89,    250,   54,    50,    2618,  57,    986,   825,   1306,  217,
+    602,   1274,  378,   1935,  2522,  719,   5882,  57,    314,   57,
+    1754,  281,   3578,  57,    4634,  3322,  54,    50,    54,    50,
+    54,    50,    54,    50,    54,    50,    54,    50,    54,    50,
+    975,   1434,  185,   54,    50,    1017,  54,    50,    54,    50,
+    54,    50,    54,    50,    54,    50,    537,   8218,  4217,  54,
+    50,    54,    50,    54,    50,    54,    50,    54,    50,    54,
+    50,    54,    50,    54,    50,    54,    50,    54,    50,    54,
+    50,    2041,  54,    50,    54,    50,    1049,  54,    50,    8281,
+    1562,  697,   90,    217,   346,   1513,  1509,  126,   73,    69,
+    254,   105,   37,    94,    37,    94,    165,   70,    105,   37,
+    3166,  37,    218,   158,   108,   94,    149,   47,    85,    1221,
+    37,    37,    1799,  38,    53,    44,    743,   231,   231,   231,
+    231,   231,   231,   231,   231,   1036,  85,    52,    51,    52,
+    51,    117,   52,    51,    53,    52,    51,    309,   49,    85,
+    49,    53,    52,    51,    85,    52,    51,    54,    50,    54,
+    50,    54,    50,    54,    50,    181,   38,    341,   81,    858,
+    2874,  6874,  410,   61,    117,   58,    38,    39,    46,    54,
+    50,    54,    50,    54,    50,    54,    50,    54,    50,    90,
+    54,    50,    54,    50,    54,    50,    54,    50,    49,    54,
+    82,    58,    302,   140,   74,    49,    166,   90,    110,   38,
+    39,    53,    90,    2759,  76,    88,    70,    39,    49,    2887,
+    53,    102,   39,    1319,  3015,  90,    143,   346,   871,   1178,
+    519,   1018,  335,   986,   271,   58,    495,   1050,  335,   1274,
+    495,   2042,  8218,  39,    39,    2074,  39,    39,    679,   38,
+    36583, 1786,  1287,  198,   85,    8583,  38,    117,   519,   333,
+    71,    1502,  39,    44,    107,   53,    332,   53,    38,    798,
+    44,    2247,  334,   76,    213,   760,   294,   88,    478,   69,
+    2014,  38,    261,   190,   350,   38,    88,    158,   158,   382,
+    70,    37,    231,   44,    103,   44,    135,   44,    743,   74,
+    76,    42,    154,   207,   90,    55,    58,    1671,  149,   74,
+    1607,  522,   44,    85,    333,   588,   199,   117,   39,    333,
+    903,   268,   85,    743,   364,   74,    53,    935,   108,   42,
+    1511,  44,    74,    140,   74,    44,    138,   437,   38,    333,
+    85,    1319,  204,   74,    76,    74,    76,    103,   44,    263,
+    44,    42,    333,   149,   519,   38,    199,   122,   39,    42,
+    1543,  44,    39,    108,   71,    76,    167,   76,    39,    44,
+    39,    71,    38,    85,    359,   42,    76,    74,    85,    39,
+    70,    42,    44,    199,   199,   199,   231,   231,   1127,  74,
+    44,    74,    44,    74,    53,    42,    44,    333,   39,    39,
+    743,   1575,  36,    68,    68,    36,    63,    63,    11719, 3399,
+    229,   165,   39,    44,    327,   57,    423,   167,   39,    71,
+    71,    3463,  536,   11623, 54,    50,    2055,  1735,  391,   55,
+    58,    524,   245,   54,    50,    53,    236,   53,    81,    80,
+    54,    50,    54,    50,    54,    50,    54,    50,    54,    50,
+    54,    50,    54,    50,    54,    50,    85,    54,    50,    149,
+    112,   117,   149,   49,    54,    50,    54,    50,    54,    50,
+    117,   57,    49,    121,   53,    55,    85,    167,   4327,  34,
+    117,   55,    117,   54,    50,    53,    57,    53,    49,    85,
+    333,   85,    121,   85,    841,   54,    53,    50,    56,    48,
+    56,    837,   54,    57,    50,    57,    54,    50,    53,    54,
+    50,    85,    327,   38,    1447,  70,    999,   199,   199,   199,
+    103,   87,    57,    56,    58,    87,    58,    153,   90,    98,
+    90,    391,   839,   615,   71,    487,   455,   3943,  117,   1455,
+    314,   1710,  143,   570,   47,    410,   1466,  44,    935,   1575,
+    999,   143,   551,   46,    263,   46,    967,   53,    1159,  263,
+    53,    174,   1289,  1285,  2503,  333,   199,   39,    1415,  71,
+    39,    743,   53,    271,   711,   207,   53,    839,   53,    1799,
+    71,    39,    108,   76,    140,   135,   103,   871,   108,   44,
+    271,   309,   935,   79,    53,    1735,  245,   711,   271,   615,
+    271,   2343,  1007,  42,    44,    42,    1703,  492,   245,   655,
+    333,   76,    42,    1447,  106,   140,   74,    76,    85,    34,
+    149,   807,   333,   108,   1159,  172,   42,    268,   333,   149,
+    76,    42,    1543,  106,   300,   74,    135,   149,   333,   1383,
+    44,    42,    44,    74,    204,   42,    44,    333,   28135, 3182,
+    149,   34279, 18215, 2215,  39,    1482,  140,   422,   71,    7898,
+    1274,  1946,  74,    108,   122,   202,   258,   268,   90,    236,
+    986,   140,   1562,  2138,  108,   58,    2810,  591,   841,   837,
+    841,   229,   581,   841,   837,   41,    73,    41,    73,    137,
+    265,   133,   37,    229,   357,   841,   837,   73,    137,   265,
+    233,   837,   73,    137,   169,   41,    233,   837,   841,   837,
+    841,   837,   841,   837,   841,   837,   841,   837,   841,   901,
+    809,   57,    805,   57,    197,   809,   57,    805,   57,    197,
+    809,   57,    805,   57,    197,   809,   57,    805,   57,    197,
+    809,   57,    805,   57,    197,   94,    1613,  135,   871,   71,
+    39,    39,    327,   135,   39,    39,    39,    39,    39,    39,
+    103,   71,    39,    39,    39,    39,    39,    39,    71,    39,
+    135,   231,   135,   135,   39,    327,   551,   103,   167,   551,
+    89,    1434,  3226,  506,   474,   506,   506,   367,   1018,  1946,
+    1402,  954,   1402,  314,   90,    1082,  218,   2266,  666,   1210,
+    186,   570,   2042,  58,    5850,  154,   2010,  154,   794,   2266,
+    378,   2266,  3738,  39,    39,    39,    39,    39,    39,    17351,
+    34,    3074,  7692,  63,    63,
+  };
+
+static int sqlite3Fts5UnicodeCategory(u32 iCode) {
+  int iRes = -1;
+  int iHi;
+  int iLo;
+  int ret;
+  u16 iKey;
+
+  if( iCode>=(1<<20) ){
+    return 0;
+  }
+  iLo = aFts5UnicodeBlock[(iCode>>16)];
+  iHi = aFts5UnicodeBlock[1+(iCode>>16)];
+  iKey = (iCode & 0xFFFF);
+  while( iHi>iLo ){
+    int iTest = (iHi + iLo) / 2;
+    assert( iTest>=iLo && iTest<iHi );
+    if( iKey>=aFts5UnicodeMap[iTest] ){
+      iRes = iTest;
+      iLo = iTest+1;
+    }else{
+      iHi = iTest;
+    }
+  }
+
+  if( iRes<0 ) return 0;
+  if( iKey>=(aFts5UnicodeMap[iRes]+(aFts5UnicodeData[iRes]>>5)) ) return 0;
+  ret = aFts5UnicodeData[iRes] & 0x1F;
+  if( ret!=30 ) return ret;
+  return ((iKey - aFts5UnicodeMap[iRes]) & 0x01) ? 5 : 9;
+}
+
+static void sqlite3Fts5UnicodeAscii(u8 *aArray, u8 *aAscii){
+  int i = 0;
+  int iTbl = 0;
+  while( i<128 ){
+    int bToken = aArray[ aFts5UnicodeData[iTbl] & 0x1F ];
+    int n = (aFts5UnicodeData[iTbl] >> 5) + i;
+    for(; i<128 && i<n; i++){
+      aAscii[i] = (u8)bToken;
+    }
+    iTbl++;
+  }
+  aAscii[0] = 0;                  /* 0x00 is never a token character */
+}
+
+
+/*
+** 2015 May 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Routines for varint serialization and deserialization.
+*/
+
+
+/* #include "fts5Int.h" */
+
+/*
+** This is a copy of the sqlite3GetVarint32() routine from the SQLite core.
+** Except, this version does handle the single byte case that the core
+** version depends on being handled before its function is called.
+*/
+static int sqlite3Fts5GetVarint32(const unsigned char *p, u32 *v){
+  u32 a,b;
+
+  /* The 1-byte case. Overwhelmingly the most common. */
+  a = *p;
+  /* a: p0 (unmasked) */
+  if (!(a&0x80))
+  {
+    /* Values between 0 and 127 */
+    *v = a;
+    return 1;
+  }
+
+  /* The 2-byte case */
+  p++;
+  b = *p;
+  /* b: p1 (unmasked) */
+  if (!(b&0x80))
+  {
+    /* Values between 128 and 16383 */
+    a &= 0x7f;
+    a = a<<7;
+    *v = a | b;
+    return 2;
+  }
+
+  /* The 3-byte case */
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<14 | p2 (unmasked) */
+  if (!(a&0x80))
+  {
+    /* Values between 16384 and 2097151 */
+    a &= (0x7f<<14)|(0x7f);
+    b &= 0x7f;
+    b = b<<7;
+    *v = a | b;
+    return 3;
+  }
+
+  /* A 32-bit varint is used to store size information in btrees.
+  ** Objects are rarely larger than 2MiB limit of a 3-byte varint.
+  ** A 3-byte varint is sufficient, for example, to record the size
+  ** of a 1048569-byte BLOB or string.
+  **
+  ** We only unroll the first 1-, 2-, and 3- byte cases.  The very
+  ** rare larger cases can be handled by the slower 64-bit varint
+  ** routine.
+  */
+  {
+    u64 v64;
+    u8 n;
+    p -= 2;
+    n = sqlite3Fts5GetVarint(p, &v64);
+    *v = ((u32)v64) & 0x7FFFFFFF;
+    assert( n>3 && n<=9 );
+    return n;
+  }
+}
+
+
+/*
+** Bitmasks used by sqlite3GetVarint().  These precomputed constants
+** are defined here rather than simply putting the constant expressions
+** inline in order to work around bugs in the RVT compiler.
+**
+** SLOT_2_0     A mask for  (0x7f<<14) | 0x7f
+**
+** SLOT_4_2_0   A mask for  (0x7f<<28) | SLOT_2_0
+*/
+#define SLOT_2_0     0x001fc07f
+#define SLOT_4_2_0   0xf01fc07f
+
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read.  The value is stored in *v.
+*/
+static u8 sqlite3Fts5GetVarint(const unsigned char *p, u64 *v){
+  u32 a,b,s;
+
+  a = *p;
+  /* a: p0 (unmasked) */
+  if (!(a&0x80))
+  {
+    *v = a;
+    return 1;
+  }
+
+  p++;
+  b = *p;
+  /* b: p1 (unmasked) */
+  if (!(b&0x80))
+  {
+    a &= 0x7f;
+    a = a<<7;
+    a |= b;
+    *v = a;
+    return 2;
+  }
+
+  /* Verify that constants are precomputed correctly */
+  assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
+  assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<14 | p2 (unmasked) */
+  if (!(a&0x80))
+  {
+    a &= SLOT_2_0;
+    b &= 0x7f;
+    b = b<<7;
+    a |= b;
+    *v = a;
+    return 3;
+  }
+
+  /* CSE1 from below */
+  a &= SLOT_2_0;
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<14 | p3 (unmasked) */
+  if (!(b&0x80))
+  {
+    b &= SLOT_2_0;
+    /* moved CSE1 up */
+    /* a &= (0x7f<<14)|(0x7f); */
+    a = a<<7;
+    a |= b;
+    *v = a;
+    return 4;
+  }
+
+  /* a: p0<<14 | p2 (masked) */
+  /* b: p1<<14 | p3 (unmasked) */
+  /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+  /* moved CSE1 up */
+  /* a &= (0x7f<<14)|(0x7f); */
+  b &= SLOT_2_0;
+  s = a;
+  /* s: p0<<14 | p2 (masked) */
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<28 | p2<<14 | p4 (unmasked) */
+  if (!(a&0x80))
+  {
+    /* we can skip these cause they were (effectively) done above in calc'ing s */
+    /* a &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
+    /* b &= (0x7f<<14)|(0x7f); */
+    b = b<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 5;
+  }
+
+  /* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+  s = s<<7;
+  s |= b;
+  /* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<28 | p3<<14 | p5 (unmasked) */
+  if (!(b&0x80))
+  {
+    /* we can skip this cause it was (effectively) done above in calc'ing s */
+    /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
+    a &= SLOT_2_0;
+    a = a<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 6;
+  }
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p2<<28 | p4<<14 | p6 (unmasked) */
+  if (!(a&0x80))
+  {
+    a &= SLOT_4_2_0;
+    b &= SLOT_2_0;
+    b = b<<7;
+    a |= b;
+    s = s>>11;
+    *v = ((u64)s)<<32 | a;
+    return 7;
+  }
+
+  /* CSE2 from below */
+  a &= SLOT_2_0;
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p3<<28 | p5<<14 | p7 (unmasked) */
+  if (!(b&0x80))
+  {
+    b &= SLOT_4_2_0;
+    /* moved CSE2 up */
+    /* a &= (0x7f<<14)|(0x7f); */
+    a = a<<7;
+    a |= b;
+    s = s>>4;
+    *v = ((u64)s)<<32 | a;
+    return 8;
+  }
+
+  p++;
+  a = a<<15;
+  a |= *p;
+  /* a: p4<<29 | p6<<15 | p8 (unmasked) */
+
+  /* moved CSE2 up */
+  /* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
+  b &= SLOT_2_0;
+  b = b<<8;
+  a |= b;
+
+  s = s<<4;
+  b = p[-4];
+  b &= 0x7f;
+  b = b>>3;
+  s |= b;
+
+  *v = ((u64)s)<<32 | a;
+
+  return 9;
+}
+
+/*
+** The variable-length integer encoding is as follows:
+**
+** KEY:
+**         A = 0xxxxxxx    7 bits of data and one flag bit
+**         B = 1xxxxxxx    7 bits of data and one flag bit
+**         C = xxxxxxxx    8 bits of data
+**
+**  7 bits - A
+** 14 bits - BA
+** 21 bits - BBA
+** 28 bits - BBBA
+** 35 bits - BBBBA
+** 42 bits - BBBBBA
+** 49 bits - BBBBBBA
+** 56 bits - BBBBBBBA
+** 64 bits - BBBBBBBBC
+*/
+
+#ifdef SQLITE_NOINLINE
+# define FTS5_NOINLINE SQLITE_NOINLINE
+#else
+# define FTS5_NOINLINE
+#endif
+
+/*
+** Write a 64-bit variable-length integer to memory starting at p[0].
+** The length of data write will be between 1 and 9 bytes.  The number
+** of bytes written is returned.
+**
+** A variable-length integer consists of the lower 7 bits of each byte
+** for all bytes that have the 8th bit set and one byte with the 8th
+** bit clear.  Except, if we get to the 9th byte, it stores the full
+** 8 bits and is the last byte.
+*/
+static int FTS5_NOINLINE fts5PutVarint64(unsigned char *p, u64 v){
+  int i, j, n;
+  u8 buf[10];
+  if( v & (((u64)0xff000000)<<32) ){
+    p[8] = (u8)v;
+    v >>= 8;
+    for(i=7; i>=0; i--){
+      p[i] = (u8)((v & 0x7f) | 0x80);
+      v >>= 7;
+    }
+    return 9;
+  }
+  n = 0;
+  do{
+    buf[n++] = (u8)((v & 0x7f) | 0x80);
+    v >>= 7;
+  }while( v!=0 );
+  buf[0] &= 0x7f;
+  assert( n<=9 );
+  for(i=0, j=n-1; j>=0; j--, i++){
+    p[i] = buf[j];
+  }
+  return n;
+}
+
+static int sqlite3Fts5PutVarint(unsigned char *p, u64 v){
+  if( v<=0x7f ){
+    p[0] = v&0x7f;
+    return 1;
+  }
+  if( v<=0x3fff ){
+    p[0] = ((v>>7)&0x7f)|0x80;
+    p[1] = v&0x7f;
+    return 2;
+  }
+  return fts5PutVarint64(p,v);
+}
+
+
+static int sqlite3Fts5GetVarintLen(u32 iVal){
+#if 0
+  if( iVal<(1 << 7 ) ) return 1;
+#endif
+  assert( iVal>=(1 << 7) );
+  if( iVal<(1 << 14) ) return 2;
+  if( iVal<(1 << 21) ) return 3;
+  if( iVal<(1 << 28) ) return 4;
+  return 5;
+}
+
+/*
+** 2015 May 08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is an SQLite virtual table module implementing direct access to an
+** existing FTS5 index. The module may create several different types of
+** tables:
+**
+** col:
+**     CREATE TABLE vocab(term, col, doc, cnt, PRIMARY KEY(term, col));
+**
+**   One row for each term/column combination. The value of $doc is set to
+**   the number of fts5 rows that contain at least one instance of term
+**   $term within column $col. Field $cnt is set to the total number of
+**   instances of term $term in column $col (in any row of the fts5 table).
+**
+** row:
+**     CREATE TABLE vocab(term, doc, cnt, PRIMARY KEY(term));
+**
+**   One row for each term in the database. The value of $doc is set to
+**   the number of fts5 rows that contain at least one instance of term
+**   $term. Field $cnt is set to the total number of instances of term
+**   $term in the database.
+**
+** instance:
+**     CREATE TABLE vocab(term, doc, col, offset, PRIMARY KEY(<all-fields>));
+**
+**   One row for each term instance in the database.
+*/
+
+
+/* #include "fts5Int.h" */
+
+
+typedef struct Fts5VocabTable Fts5VocabTable;
+typedef struct Fts5VocabCursor Fts5VocabCursor;
+
+struct Fts5VocabTable {
+  sqlite3_vtab base;
+  char *zFts5Tbl;                 /* Name of fts5 table */
+  char *zFts5Db;                  /* Db containing fts5 table */
+  sqlite3 *db;                    /* Database handle */
+  Fts5Global *pGlobal;            /* FTS5 global object for this database */
+  int eType;                      /* FTS5_VOCAB_COL, ROW or INSTANCE */
+  unsigned bBusy;                 /* True if busy */
+};
+
+struct Fts5VocabCursor {
+  sqlite3_vtab_cursor base;
+  sqlite3_stmt *pStmt;            /* Statement holding lock on pIndex */
+  Fts5Table *pFts5;               /* Associated FTS5 table */
+
+  int bEof;                       /* True if this cursor is at EOF */
+  Fts5IndexIter *pIter;           /* Term/rowid iterator object */
+  void *pStruct;                  /* From sqlite3Fts5StructureRef() */
+
+  int nLeTerm;                    /* Size of zLeTerm in bytes */
+  char *zLeTerm;                  /* (term <= $zLeTerm) paramater, or NULL */
+  int colUsed;                    /* Copy of sqlite3_index_info.colUsed */
+
+  /* These are used by 'col' tables only */
+  int iCol;
+  i64 *aCnt;
+  i64 *aDoc;
+
+  /* Output values used by all tables. */
+  i64 rowid;                      /* This table's current rowid value */
+  Fts5Buffer term;                /* Current value of 'term' column */
+
+  /* Output values Used by 'instance' tables only */
+  i64 iInstPos;
+  int iInstOff;
+};
+
+#define FTS5_VOCAB_COL      0
+#define FTS5_VOCAB_ROW      1
+#define FTS5_VOCAB_INSTANCE 2
+
+#define FTS5_VOCAB_COL_SCHEMA  "term, col, doc, cnt"
+#define FTS5_VOCAB_ROW_SCHEMA  "term, doc, cnt"
+#define FTS5_VOCAB_INST_SCHEMA "term, doc, col, offset"
+
+/*
+** Bits for the mask used as the idxNum value by xBestIndex/xFilter.
+*/
+#define FTS5_VOCAB_TERM_EQ 0x0100
+#define FTS5_VOCAB_TERM_GE 0x0200
+#define FTS5_VOCAB_TERM_LE 0x0400
+
+#define FTS5_VOCAB_COLUSED_MASK 0xFF
+
+
+/*
+** Translate a string containing an fts5vocab table type to an
+** FTS5_VOCAB_XXX constant. If successful, set *peType to the output
+** value and return SQLITE_OK. Otherwise, set *pzErr to an error message
+** and return SQLITE_ERROR.
+*/
+static int fts5VocabTableType(const char *zType, char **pzErr, int *peType){
+  int rc = SQLITE_OK;
+  char *zCopy = sqlite3Fts5Strndup(&rc, zType, -1);
+  if( rc==SQLITE_OK ){
+    sqlite3Fts5Dequote(zCopy);
+    if( sqlite3_stricmp(zCopy, "col")==0 ){
+      *peType = FTS5_VOCAB_COL;
+    }else
+
+    if( sqlite3_stricmp(zCopy, "row")==0 ){
+      *peType = FTS5_VOCAB_ROW;
+    }else
+    if( sqlite3_stricmp(zCopy, "instance")==0 ){
+      *peType = FTS5_VOCAB_INSTANCE;
+    }else
+    {
+      *pzErr = sqlite3_mprintf("fts5vocab: unknown table type: %Q", zCopy);
+      rc = SQLITE_ERROR;
+    }
+    sqlite3_free(zCopy);
+  }
+
+  return rc;
+}
+
+
+/*
+** The xDisconnect() virtual table method.
+*/
+static int fts5VocabDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pVtab;
+  sqlite3_free(pTab);
+  return SQLITE_OK;
+}
+
+/*
+** The xDestroy() virtual table method.
+*/
+static int fts5VocabDestroyMethod(sqlite3_vtab *pVtab){
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pVtab;
+  sqlite3_free(pTab);
+  return SQLITE_OK;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the FTS3 virtual table.
+**
+** The argv[] array contains the following:
+**
+**   argv[0]   -> module name  ("fts5vocab")
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**
+** then:
+**
+**   argv[3]   -> name of fts5 table
+**   argv[4]   -> type of fts5vocab table
+**
+** or, for tables in the TEMP schema only.
+**
+**   argv[3]   -> name of fts5 tables database
+**   argv[4]   -> name of fts5 table
+**   argv[5]   -> type of fts5vocab table
+*/
+static int fts5VocabInitVtab(
+  sqlite3 *db,                    /* The SQLite database connection */
+  void *pAux,                     /* Pointer to Fts5Global object */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
+  char **pzErr                    /* Write any error message here */
+){
+  const char *azSchema[] = {
+    "CREATE TABlE vocab(" FTS5_VOCAB_COL_SCHEMA  ")",
+    "CREATE TABlE vocab(" FTS5_VOCAB_ROW_SCHEMA  ")",
+    "CREATE TABlE vocab(" FTS5_VOCAB_INST_SCHEMA ")"
+  };
+
+  Fts5VocabTable *pRet = 0;
+  int rc = SQLITE_OK;             /* Return code */
+  int bDb;
+
+  bDb = (argc==6 && strlen(argv[1])==4 && memcmp("temp", argv[1], 4)==0);
+
+  if( argc!=5 && bDb==0 ){
+    *pzErr = sqlite3_mprintf("wrong number of vtable arguments");
+    rc = SQLITE_ERROR;
+  }else{
+    int nByte;                      /* Bytes of space to allocate */
+    const char *zDb = bDb ? argv[3] : argv[1];
+    const char *zTab = bDb ? argv[4] : argv[3];
+    const char *zType = bDb ? argv[5] : argv[4];
+    int nDb = (int)strlen(zDb)+1;
+    int nTab = (int)strlen(zTab)+1;
+    int eType = 0;
+
+    rc = fts5VocabTableType(zType, pzErr, &eType);
+    if( rc==SQLITE_OK ){
+      assert( eType>=0 && eType<ArraySize(azSchema) );
+      rc = sqlite3_declare_vtab(db, azSchema[eType]);
+    }
+
+    nByte = sizeof(Fts5VocabTable) + nDb + nTab;
+    pRet = sqlite3Fts5MallocZero(&rc, nByte);
+    if( pRet ){
+      pRet->pGlobal = (Fts5Global*)pAux;
+      pRet->eType = eType;
+      pRet->db = db;
+      pRet->zFts5Tbl = (char*)&pRet[1];
+      pRet->zFts5Db = &pRet->zFts5Tbl[nTab];
+      memcpy(pRet->zFts5Tbl, zTab, nTab);
+      memcpy(pRet->zFts5Db, zDb, nDb);
+      sqlite3Fts5Dequote(pRet->zFts5Tbl);
+      sqlite3Fts5Dequote(pRet->zFts5Db);
+    }
+  }
+
+  *ppVTab = (sqlite3_vtab*)pRet;
+  return rc;
+}
+
+
+/*
+** The xConnect() and xCreate() methods for the virtual table. All the
+** work is done in function fts5VocabInitVtab().
+*/
+static int fts5VocabConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5VocabInitVtab(db, pAux, argc, argv, ppVtab, pzErr);
+}
+static int fts5VocabCreateMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5VocabInitVtab(db, pAux, argc, argv, ppVtab, pzErr);
+}
+
+/*
+** Implementation of the xBestIndex method.
+**
+** Only constraints of the form:
+**
+**     term <= ?
+**     term == ?
+**     term >= ?
+**
+** are interpreted. Less-than and less-than-or-equal are treated
+** identically, as are greater-than and greater-than-or-equal.
+*/
+static int fts5VocabBestIndexMethod(
+  sqlite3_vtab *pUnused,
+  sqlite3_index_info *pInfo
+){
+  int i;
+  int iTermEq = -1;
+  int iTermGe = -1;
+  int iTermLe = -1;
+  int idxNum = (int)pInfo->colUsed;
+  int nArg = 0;
+
+  UNUSED_PARAM(pUnused);
+
+  assert( (pInfo->colUsed & FTS5_VOCAB_COLUSED_MASK)==pInfo->colUsed );
+
+  for(i=0; i<pInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *p = &pInfo->aConstraint[i];
+    if( p->usable==0 ) continue;
+    if( p->iColumn==0 ){          /* term column */
+      if( p->op==SQLITE_INDEX_CONSTRAINT_EQ ) iTermEq = i;
+      if( p->op==SQLITE_INDEX_CONSTRAINT_LE ) iTermLe = i;
+      if( p->op==SQLITE_INDEX_CONSTRAINT_LT ) iTermLe = i;
+      if( p->op==SQLITE_INDEX_CONSTRAINT_GE ) iTermGe = i;
+      if( p->op==SQLITE_INDEX_CONSTRAINT_GT ) iTermGe = i;
+    }
+  }
+
+  if( iTermEq>=0 ){
+    idxNum |= FTS5_VOCAB_TERM_EQ;
+    pInfo->aConstraintUsage[iTermEq].argvIndex = ++nArg;
+    pInfo->estimatedCost = 100;
+  }else{
+    pInfo->estimatedCost = 1000000;
+    if( iTermGe>=0 ){
+      idxNum |= FTS5_VOCAB_TERM_GE;
+      pInfo->aConstraintUsage[iTermGe].argvIndex = ++nArg;
+      pInfo->estimatedCost = pInfo->estimatedCost / 2;
+    }
+    if( iTermLe>=0 ){
+      idxNum |= FTS5_VOCAB_TERM_LE;
+      pInfo->aConstraintUsage[iTermLe].argvIndex = ++nArg;
+      pInfo->estimatedCost = pInfo->estimatedCost / 2;
+    }
+  }
+
+  /* This virtual table always delivers results in ascending order of
+  ** the "term" column (column 0). So if the user has requested this
+  ** specifically - "ORDER BY term" or "ORDER BY term ASC" - set the
+  ** sqlite3_index_info.orderByConsumed flag to tell the core the results
+  ** are already in sorted order.  */
+  if( pInfo->nOrderBy==1
+   && pInfo->aOrderBy[0].iColumn==0
+   && pInfo->aOrderBy[0].desc==0
+  ){
+    pInfo->orderByConsumed = 1;
+  }
+
+  pInfo->idxNum = idxNum;
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xOpen method.
+*/
+static int fts5VocabOpenMethod(
+  sqlite3_vtab *pVTab,
+  sqlite3_vtab_cursor **ppCsr
+){
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pVTab;
+  Fts5Table *pFts5 = 0;
+  Fts5VocabCursor *pCsr = 0;
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pStmt = 0;
+  char *zSql = 0;
+
+  if( pTab->bBusy ){
+    pVTab->zErrMsg = sqlite3_mprintf(
+       "recursive definition for %s.%s", pTab->zFts5Db, pTab->zFts5Tbl
+    );
+    return SQLITE_ERROR;
+  }
+  zSql = sqlite3Fts5Mprintf(&rc,
+      "SELECT t.%Q FROM %Q.%Q AS t WHERE t.%Q MATCH '*id'",
+      pTab->zFts5Tbl, pTab->zFts5Db, pTab->zFts5Tbl, pTab->zFts5Tbl
+  );
+  if( zSql ){
+    rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pStmt, 0);
+  }
+  sqlite3_free(zSql);
+  assert( rc==SQLITE_OK || pStmt==0 );
+  if( rc==SQLITE_ERROR ) rc = SQLITE_OK;
+
+  pTab->bBusy = 1;
+  if( pStmt && sqlite3_step(pStmt)==SQLITE_ROW ){
+    i64 iId = sqlite3_column_int64(pStmt, 0);
+    pFts5 = sqlite3Fts5TableFromCsrid(pTab->pGlobal, iId);
+  }
+  pTab->bBusy = 0;
+
+  if( rc==SQLITE_OK ){
+    if( pFts5==0 ){
+      rc = sqlite3_finalize(pStmt);
+      pStmt = 0;
+      if( rc==SQLITE_OK ){
+        pVTab->zErrMsg = sqlite3_mprintf(
+            "no such fts5 table: %s.%s", pTab->zFts5Db, pTab->zFts5Tbl
+        );
+        rc = SQLITE_ERROR;
+      }
+    }else{
+      rc = sqlite3Fts5FlushToDisk(pFts5);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    i64 nByte = pFts5->pConfig->nCol * sizeof(i64)*2 + sizeof(Fts5VocabCursor);
+    pCsr = (Fts5VocabCursor*)sqlite3Fts5MallocZero(&rc, nByte);
+  }
+
+  if( pCsr ){
+    pCsr->pFts5 = pFts5;
+    pCsr->pStmt = pStmt;
+    pCsr->aCnt = (i64*)&pCsr[1];
+    pCsr->aDoc = &pCsr->aCnt[pFts5->pConfig->nCol];
+  }else{
+    sqlite3_finalize(pStmt);
+  }
+
+  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
+  return rc;
+}
+
+static void fts5VocabResetCursor(Fts5VocabCursor *pCsr){
+  pCsr->rowid = 0;
+  sqlite3Fts5IterClose(pCsr->pIter);
+  sqlite3Fts5StructureRelease(pCsr->pStruct);
+  pCsr->pStruct = 0;
+  pCsr->pIter = 0;
+  sqlite3_free(pCsr->zLeTerm);
+  pCsr->nLeTerm = -1;
+  pCsr->zLeTerm = 0;
+  pCsr->bEof = 0;
+}
+
+/*
+** Close the cursor.  For additional information see the documentation
+** on the xClose method of the virtual table interface.
+*/
+static int fts5VocabCloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  fts5VocabResetCursor(pCsr);
+  sqlite3Fts5BufferFree(&pCsr->term);
+  sqlite3_finalize(pCsr->pStmt);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+static int fts5VocabInstanceNewTerm(Fts5VocabCursor *pCsr){
+  int rc = SQLITE_OK;
+
+  if( sqlite3Fts5IterEof(pCsr->pIter) ){
+    pCsr->bEof = 1;
+  }else{
+    const char *zTerm;
+    int nTerm;
+    zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
+    if( pCsr->nLeTerm>=0 ){
+      int nCmp = MIN(nTerm, pCsr->nLeTerm);
+      int bCmp = memcmp(pCsr->zLeTerm, zTerm, nCmp);
+      if( bCmp<0 || (bCmp==0 && pCsr->nLeTerm<nTerm) ){
+        pCsr->bEof = 1;
+      }
+    }
+
+    sqlite3Fts5BufferSet(&rc, &pCsr->term, nTerm, (const u8*)zTerm);
+  }
+  return rc;
+}
+
+static int fts5VocabInstanceNext(Fts5VocabCursor *pCsr){
+  int eDetail = pCsr->pFts5->pConfig->eDetail;
+  int rc = SQLITE_OK;
+  Fts5IndexIter *pIter = pCsr->pIter;
+  i64 *pp = &pCsr->iInstPos;
+  int *po = &pCsr->iInstOff;
+
+  assert( sqlite3Fts5IterEof(pIter)==0 );
+  assert( pCsr->bEof==0 );
+  while( eDetail==FTS5_DETAIL_NONE
+      || sqlite3Fts5PoslistNext64(pIter->pData, pIter->nData, po, pp)
+  ){
+    pCsr->iInstPos = 0;
+    pCsr->iInstOff = 0;
+
+    rc = sqlite3Fts5IterNextScan(pCsr->pIter);
+    if( rc==SQLITE_OK ){
+      rc = fts5VocabInstanceNewTerm(pCsr);
+      if( pCsr->bEof || eDetail==FTS5_DETAIL_NONE ) break;
+    }
+    if( rc ){
+      pCsr->bEof = 1;
+      break;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Advance the cursor to the next row in the table.
+*/
+static int fts5VocabNextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pCursor->pVtab;
+  int nCol = pCsr->pFts5->pConfig->nCol;
+  int rc;
+
+  rc = sqlite3Fts5StructureTest(pCsr->pFts5->pIndex, pCsr->pStruct);
+  if( rc!=SQLITE_OK ) return rc;
+  pCsr->rowid++;
+
+  if( pTab->eType==FTS5_VOCAB_INSTANCE ){
+    return fts5VocabInstanceNext(pCsr);
+  }
+
+  if( pTab->eType==FTS5_VOCAB_COL ){
+    for(pCsr->iCol++; pCsr->iCol<nCol; pCsr->iCol++){
+      if( pCsr->aDoc[pCsr->iCol] ) break;
+    }
+  }
+
+  if( pTab->eType!=FTS5_VOCAB_COL || pCsr->iCol>=nCol ){
+    if( sqlite3Fts5IterEof(pCsr->pIter) ){
+      pCsr->bEof = 1;
+    }else{
+      const char *zTerm;
+      int nTerm;
+
+      zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
+      assert( nTerm>=0 );
+      if( pCsr->nLeTerm>=0 ){
+        int nCmp = MIN(nTerm, pCsr->nLeTerm);
+        int bCmp = memcmp(pCsr->zLeTerm, zTerm, nCmp);
+        if( bCmp<0 || (bCmp==0 && pCsr->nLeTerm<nTerm) ){
+          pCsr->bEof = 1;
+          return SQLITE_OK;
+        }
+      }
+
+      sqlite3Fts5BufferSet(&rc, &pCsr->term, nTerm, (const u8*)zTerm);
+      memset(pCsr->aCnt, 0, nCol * sizeof(i64));
+      memset(pCsr->aDoc, 0, nCol * sizeof(i64));
+      pCsr->iCol = 0;
+
+      assert( pTab->eType==FTS5_VOCAB_COL || pTab->eType==FTS5_VOCAB_ROW );
+      while( rc==SQLITE_OK ){
+        int eDetail = pCsr->pFts5->pConfig->eDetail;
+        const u8 *pPos; int nPos;   /* Position list */
+        i64 iPos = 0;               /* 64-bit position read from poslist */
+        int iOff = 0;               /* Current offset within position list */
+
+        pPos = pCsr->pIter->pData;
+        nPos = pCsr->pIter->nData;
+
+        switch( pTab->eType ){
+          case FTS5_VOCAB_ROW:
+            /* Do not bother counting the number of instances if the "cnt"
+            ** column is not being read (according to colUsed).  */
+            if( eDetail==FTS5_DETAIL_FULL && (pCsr->colUsed & 0x04) ){
+              while( iPos<nPos ){
+                u32 ii;
+                fts5FastGetVarint32(pPos, iPos, ii);
+                if( ii==1 ){
+                  /* New column in the position list */
+                  fts5FastGetVarint32(pPos, iPos, ii);
+                }else{
+                  /* An instance - increment pCsr->aCnt[] */
+                  pCsr->aCnt[0]++;
+                }
+              }
+            }
+            pCsr->aDoc[0]++;
+            break;
+
+          case FTS5_VOCAB_COL:
+            if( eDetail==FTS5_DETAIL_FULL ){
+              int iCol = -1;
+              while( 0==sqlite3Fts5PoslistNext64(pPos, nPos, &iOff, &iPos) ){
+                int ii = FTS5_POS2COLUMN(iPos);
+                if( iCol!=ii ){
+                  if( ii>=nCol ){
+                    rc = FTS5_CORRUPT;
+                    break;
+                  }
+                  pCsr->aDoc[ii]++;
+                  iCol = ii;
+                }
+                pCsr->aCnt[ii]++;
+              }
+            }else if( eDetail==FTS5_DETAIL_COLUMNS ){
+              while( 0==sqlite3Fts5PoslistNext64(pPos, nPos, &iOff,&iPos) ){
+                assert_nc( iPos>=0 && iPos<nCol );
+                if( iPos>=nCol ){
+                  rc = FTS5_CORRUPT;
+                  break;
+                }
+                pCsr->aDoc[iPos]++;
+              }
+            }else{
+              assert( eDetail==FTS5_DETAIL_NONE );
+              pCsr->aDoc[0]++;
+            }
+            break;
+
+          default:
+            assert( pTab->eType==FTS5_VOCAB_INSTANCE );
+            break;
+        }
+
+        if( rc==SQLITE_OK ){
+          rc = sqlite3Fts5IterNextScan(pCsr->pIter);
+        }
+        if( pTab->eType==FTS5_VOCAB_INSTANCE ) break;
+
+        if( rc==SQLITE_OK ){
+          zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
+          if( nTerm!=pCsr->term.n
+          || (nTerm>0 && memcmp(zTerm, pCsr->term.p, nTerm))
+          ){
+            break;
+          }
+          if( sqlite3Fts5IterEof(pCsr->pIter) ) break;
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK && pCsr->bEof==0 && pTab->eType==FTS5_VOCAB_COL ){
+    for(/* noop */; pCsr->iCol<nCol && pCsr->aDoc[pCsr->iCol]==0; pCsr->iCol++);
+    if( pCsr->iCol==nCol ){
+      rc = FTS5_CORRUPT;
+    }
+  }
+  return rc;
+}
+
+/*
+** This is the xFilter implementation for the virtual table.
+*/
+static int fts5VocabFilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *zUnused,            /* Unused */
+  int nUnused,                    /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pCursor->pVtab;
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  int eType = pTab->eType;
+  int rc = SQLITE_OK;
+
+  int iVal = 0;
+  int f = FTS5INDEX_QUERY_SCAN;
+  const char *zTerm = 0;
+  int nTerm = 0;
+
+  sqlite3_value *pEq = 0;
+  sqlite3_value *pGe = 0;
+  sqlite3_value *pLe = 0;
+
+  UNUSED_PARAM2(zUnused, nUnused);
+
+  fts5VocabResetCursor(pCsr);
+  if( idxNum & FTS5_VOCAB_TERM_EQ ) pEq = apVal[iVal++];
+  if( idxNum & FTS5_VOCAB_TERM_GE ) pGe = apVal[iVal++];
+  if( idxNum & FTS5_VOCAB_TERM_LE ) pLe = apVal[iVal++];
+  pCsr->colUsed = (idxNum & FTS5_VOCAB_COLUSED_MASK);
+
+  if( pEq ){
+    zTerm = (const char *)sqlite3_value_text(pEq);
+    nTerm = sqlite3_value_bytes(pEq);
+    f = FTS5INDEX_QUERY_NOTOKENDATA;
+  }else{
+    if( pGe ){
+      zTerm = (const char *)sqlite3_value_text(pGe);
+      nTerm = sqlite3_value_bytes(pGe);
+    }
+    if( pLe ){
+      const char *zCopy = (const char *)sqlite3_value_text(pLe);
+      if( zCopy==0 ) zCopy = "";
+      pCsr->nLeTerm = sqlite3_value_bytes(pLe);
+      pCsr->zLeTerm = sqlite3_malloc(pCsr->nLeTerm+1);
+      if( pCsr->zLeTerm==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memcpy(pCsr->zLeTerm, zCopy, pCsr->nLeTerm+1);
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    Fts5Index *pIndex = pCsr->pFts5->pIndex;
+    rc = sqlite3Fts5IndexQuery(pIndex, zTerm, nTerm, f, 0, &pCsr->pIter);
+    if( rc==SQLITE_OK ){
+      pCsr->pStruct = sqlite3Fts5StructureRef(pIndex);
+    }
+  }
+  if( rc==SQLITE_OK && eType==FTS5_VOCAB_INSTANCE ){
+    rc = fts5VocabInstanceNewTerm(pCsr);
+  }
+  if( rc==SQLITE_OK && !pCsr->bEof
+   && (eType!=FTS5_VOCAB_INSTANCE
+    || pCsr->pFts5->pConfig->eDetail!=FTS5_DETAIL_NONE)
+  ){
+    rc = fts5VocabNextMethod(pCursor);
+  }
+
+  return rc;
+}
+
+/*
+** This is the xEof method of the virtual table. SQLite calls this
+** routine to find out if it has reached the end of a result set.
+*/
+static int fts5VocabEofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  return pCsr->bEof;
+}
+
+static int fts5VocabColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  int eDetail = pCsr->pFts5->pConfig->eDetail;
+  int eType = ((Fts5VocabTable*)(pCursor->pVtab))->eType;
+  i64 iVal = 0;
+
+  if( iCol==0 ){
+    sqlite3_result_text(
+        pCtx, (const char*)pCsr->term.p, pCsr->term.n, SQLITE_TRANSIENT
+    );
+  }else if( eType==FTS5_VOCAB_COL ){
+    assert( iCol==1 || iCol==2 || iCol==3 );
+    if( iCol==1 ){
+      if( eDetail!=FTS5_DETAIL_NONE ){
+        const char *z = pCsr->pFts5->pConfig->azCol[pCsr->iCol];
+        sqlite3_result_text(pCtx, z, -1, SQLITE_STATIC);
+      }
+    }else if( iCol==2 ){
+      iVal = pCsr->aDoc[pCsr->iCol];
+    }else{
+      iVal = pCsr->aCnt[pCsr->iCol];
+    }
+  }else if( eType==FTS5_VOCAB_ROW ){
+    assert( iCol==1 || iCol==2 );
+    if( iCol==1 ){
+      iVal = pCsr->aDoc[0];
+    }else{
+      iVal = pCsr->aCnt[0];
+    }
+  }else{
+    assert( eType==FTS5_VOCAB_INSTANCE );
+    switch( iCol ){
+      case 1:
+        sqlite3_result_int64(pCtx, pCsr->pIter->iRowid);
+        break;
+      case 2: {
+        int ii = -1;
+        if( eDetail==FTS5_DETAIL_FULL ){
+          ii = FTS5_POS2COLUMN(pCsr->iInstPos);
+        }else if( eDetail==FTS5_DETAIL_COLUMNS ){
+          ii = (int)pCsr->iInstPos;
+        }
+        if( ii>=0 && ii<pCsr->pFts5->pConfig->nCol ){
+          const char *z = pCsr->pFts5->pConfig->azCol[ii];
+          sqlite3_result_text(pCtx, z, -1, SQLITE_STATIC);
+        }
+        break;
+      }
+      default: {
+        assert( iCol==3 );
+        if( eDetail==FTS5_DETAIL_FULL ){
+          int ii = FTS5_POS2OFFSET(pCsr->iInstPos);
+          sqlite3_result_int(pCtx, ii);
+        }
+        break;
+      }
+    }
+  }
+
+  if( iVal>0 ) sqlite3_result_int64(pCtx, iVal);
+  return SQLITE_OK;
+}
+
+/*
+** This is the xRowid method. The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set. The
+** rowid should be written to *pRowid.
+*/
+static int fts5VocabRowidMethod(
+  sqlite3_vtab_cursor *pCursor,
+  sqlite_int64 *pRowid
+){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  *pRowid = pCsr->rowid;
+  return SQLITE_OK;
+}
+
+static int sqlite3Fts5VocabInit(Fts5Global *pGlobal, sqlite3 *db){
+  static const sqlite3_module fts5Vocab = {
+    /* iVersion      */ 2,
+    /* xCreate       */ fts5VocabCreateMethod,
+    /* xConnect      */ fts5VocabConnectMethod,
+    /* xBestIndex    */ fts5VocabBestIndexMethod,
+    /* xDisconnect   */ fts5VocabDisconnectMethod,
+    /* xDestroy      */ fts5VocabDestroyMethod,
+    /* xOpen         */ fts5VocabOpenMethod,
+    /* xClose        */ fts5VocabCloseMethod,
+    /* xFilter       */ fts5VocabFilterMethod,
+    /* xNext         */ fts5VocabNextMethod,
+    /* xEof          */ fts5VocabEofMethod,
+    /* xColumn       */ fts5VocabColumnMethod,
+    /* xRowid        */ fts5VocabRowidMethod,
+    /* xUpdate       */ 0,
+    /* xBegin        */ 0,
+    /* xSync         */ 0,
+    /* xCommit       */ 0,
+    /* xRollback     */ 0,
+    /* xFindFunction */ 0,
+    /* xRename       */ 0,
+    /* xSavepoint    */ 0,
+    /* xRelease      */ 0,
+    /* xRollbackTo   */ 0,
+    /* xShadowName   */ 0,
+    /* xIntegrity    */ 0
+  };
+  void *p = (void*)pGlobal;
+
+  return sqlite3_create_module_v2(db, "fts5vocab", &fts5Vocab, p, 0);
+}
+
+
+/* Here ends the fts5.c composite file. */
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS5) */
+
+/************** End of fts5.c ************************************************/
+/************** Begin file stmt.c ********************************************/
+/*
+** 2017-05-31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file demonstrates an eponymous virtual table that returns information
+** about all prepared statements for the database connection.
+**
+** Usage example:
+**
+**     .load ./stmt
+**     .mode line
+**     .header on
+**     SELECT * FROM stmt;
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_STMTVTAB)
+#if !defined(SQLITEINT_H)
+/* #include "sqlite3ext.h" */
+#endif
+SQLITE_EXTENSION_INIT1
+/* #include <assert.h> */
+/* #include <string.h> */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+
+
+#define STMT_NUM_INTEGER_COLUMN 10
+typedef struct StmtRow StmtRow;
+struct StmtRow {
+  sqlite3_int64 iRowid;                /* Rowid value */
+  char *zSql;                          /* column "sql" */
+  int aCol[STMT_NUM_INTEGER_COLUMN+1]; /* all other column values */
+  StmtRow *pNext;                      /* Next row to return */
+};
+
+/* stmt_vtab is a subclass of sqlite3_vtab which will
+** serve as the underlying representation of a stmt virtual table
+*/
+typedef struct stmt_vtab stmt_vtab;
+struct stmt_vtab {
+  sqlite3_vtab base;  /* Base class - must be first */
+  sqlite3 *db;        /* Database connection for this stmt vtab */
+};
+
+/* stmt_cursor is a subclass of sqlite3_vtab_cursor which will
+** serve as the underlying representation of a cursor that scans
+** over rows of the result
+*/
+typedef struct stmt_cursor stmt_cursor;
+struct stmt_cursor {
+  sqlite3_vtab_cursor base;  /* Base class - must be first */
+  sqlite3 *db;               /* Database connection for this cursor */
+  StmtRow *pRow;             /* Current row */
+};
+
+/*
+** The stmtConnect() method is invoked to create a new
+** stmt_vtab that describes the stmt virtual table.
+**
+** Think of this routine as the constructor for stmt_vtab objects.
+**
+** All this routine needs to do is:
+**
+**    (1) Allocate the stmt_vtab object and initialize all fields.
+**
+**    (2) Tell SQLite (via the sqlite3_declare_vtab() interface) what the
+**        result set of queries against stmt will look like.
+*/
+static int stmtConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  stmt_vtab *pNew;
+  int rc;
+
+/* Column numbers */
+#define STMT_COLUMN_SQL     0   /* SQL for the statement */
+#define STMT_COLUMN_NCOL    1   /* Number of result columns */
+#define STMT_COLUMN_RO      2   /* True if read-only */
+#define STMT_COLUMN_BUSY    3   /* True if currently busy */
+#define STMT_COLUMN_NSCAN   4   /* SQLITE_STMTSTATUS_FULLSCAN_STEP */
+#define STMT_COLUMN_NSORT   5   /* SQLITE_STMTSTATUS_SORT */
+#define STMT_COLUMN_NAIDX   6   /* SQLITE_STMTSTATUS_AUTOINDEX */
+#define STMT_COLUMN_NSTEP   7   /* SQLITE_STMTSTATUS_VM_STEP */
+#define STMT_COLUMN_REPREP  8   /* SQLITE_STMTSTATUS_REPREPARE */
+#define STMT_COLUMN_RUN     9   /* SQLITE_STMTSTATUS_RUN */
+#define STMT_COLUMN_MEM    10   /* SQLITE_STMTSTATUS_MEMUSED */
+
+
+  (void)pAux;
+  (void)argc;
+  (void)argv;
+  (void)pzErr;
+  rc = sqlite3_declare_vtab(db,
+     "CREATE TABLE x(sql,ncol,ro,busy,nscan,nsort,naidx,nstep,"
+                    "reprep,run,mem)");
+  if( rc==SQLITE_OK ){
+    pNew = sqlite3_malloc64( sizeof(*pNew) );
+    *ppVtab = (sqlite3_vtab*)pNew;
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, sizeof(*pNew));
+    pNew->db = db;
+  }
+  return rc;
+}
+
+/*
+** This method is the destructor for stmt_cursor objects.
+*/
+static int stmtDisconnect(sqlite3_vtab *pVtab){
+  sqlite3_free(pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** Constructor for a new stmt_cursor object.
+*/
+static int stmtOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+  stmt_cursor *pCur;
+  pCur = sqlite3_malloc64( sizeof(*pCur) );
+  if( pCur==0 ) return SQLITE_NOMEM;
+  memset(pCur, 0, sizeof(*pCur));
+  pCur->db = ((stmt_vtab*)p)->db;
+  *ppCursor = &pCur->base;
+  return SQLITE_OK;
+}
+
+static void stmtCsrReset(stmt_cursor *pCur){
+  StmtRow *pRow = 0;
+  StmtRow *pNext = 0;
+  for(pRow=pCur->pRow; pRow; pRow=pNext){
+    pNext = pRow->pNext;
+    sqlite3_free(pRow);
+  }
+  pCur->pRow = 0;
+}
+
+/*
+** Destructor for a stmt_cursor.
+*/
+static int stmtClose(sqlite3_vtab_cursor *cur){
+  stmtCsrReset((stmt_cursor*)cur);
+  sqlite3_free(cur);
+  return SQLITE_OK;
+}
+
+
+/*
+** Advance a stmt_cursor to its next row of output.
+*/
+static int stmtNext(sqlite3_vtab_cursor *cur){
+  stmt_cursor *pCur = (stmt_cursor*)cur;
+  StmtRow *pNext = pCur->pRow->pNext;
+  sqlite3_free(pCur->pRow);
+  pCur->pRow = pNext;
+  return SQLITE_OK;
+}
+
+/*
+** Return values of columns for the row at which the stmt_cursor
+** is currently pointing.
+*/
+static int stmtColumn(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int i                       /* Which column to return */
+){
+  stmt_cursor *pCur = (stmt_cursor*)cur;
+  StmtRow *pRow = pCur->pRow;
+  if( i==STMT_COLUMN_SQL ){
+    sqlite3_result_text(ctx, pRow->zSql, -1, SQLITE_TRANSIENT);
+  }else{
+    sqlite3_result_int(ctx, pRow->aCol[i]);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return the rowid for the current row.  In this implementation, the
+** rowid is the same as the output value.
+*/
+static int stmtRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+  stmt_cursor *pCur = (stmt_cursor*)cur;
+  *pRowid = pCur->pRow->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the cursor has been moved off of the last
+** row of output.
+*/
+static int stmtEof(sqlite3_vtab_cursor *cur){
+  stmt_cursor *pCur = (stmt_cursor*)cur;
+  return pCur->pRow==0;
+}
+
+/*
+** This method is called to "rewind" the stmt_cursor object back
+** to the first row of output.  This method is always called at least
+** once prior to any call to stmtColumn() or stmtRowid() or
+** stmtEof().
+*/
+static int stmtFilter(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  stmt_cursor *pCur = (stmt_cursor *)pVtabCursor;
+  sqlite3_stmt *p = 0;
+  sqlite3_int64 iRowid = 1;
+  StmtRow **ppRow = 0;
+
+  (void)idxNum;
+  (void)idxStr;
+  (void)argc;
+  (void)argv;
+  stmtCsrReset(pCur);
+  ppRow = &pCur->pRow;
+  for(p=sqlite3_next_stmt(pCur->db, 0); p; p=sqlite3_next_stmt(pCur->db, p)){
+    const char *zSql = sqlite3_sql(p);
+    sqlite3_int64 nSql = zSql ? strlen(zSql)+1 : 0;
+    StmtRow *pNew = (StmtRow*)sqlite3_malloc64(sizeof(StmtRow) + nSql);
+
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, sizeof(StmtRow));
+    if( zSql ){
+      pNew->zSql = (char*)&pNew[1];
+      memcpy(pNew->zSql, zSql, nSql);
+    }
+    pNew->aCol[STMT_COLUMN_NCOL] = sqlite3_column_count(p);
+    pNew->aCol[STMT_COLUMN_RO] = sqlite3_stmt_readonly(p);
+    pNew->aCol[STMT_COLUMN_BUSY] = sqlite3_stmt_busy(p);
+    pNew->aCol[STMT_COLUMN_NSCAN] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_FULLSCAN_STEP, 0
+    );
+    pNew->aCol[STMT_COLUMN_NSORT] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_SORT, 0
+    );
+    pNew->aCol[STMT_COLUMN_NAIDX] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_AUTOINDEX, 0
+    );
+    pNew->aCol[STMT_COLUMN_NSTEP] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_VM_STEP, 0
+    );
+    pNew->aCol[STMT_COLUMN_REPREP] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_REPREPARE, 0
+    );
+    pNew->aCol[STMT_COLUMN_RUN] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_RUN, 0
+    );
+    pNew->aCol[STMT_COLUMN_MEM] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_MEMUSED, 0
+    );
+    pNew->iRowid = iRowid++;
+    *ppRow = pNew;
+    ppRow = &pNew->pNext;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** SQLite will invoke this method one or more times while planning a query
+** that uses the stmt virtual table.  This routine needs to create
+** a query plan for each invocation and compute an estimated cost for that
+** plan.
+*/
+static int stmtBestIndex(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  (void)tab;
+  pIdxInfo->estimatedCost = (double)500;
+  pIdxInfo->estimatedRows = 500;
+  return SQLITE_OK;
+}
+
+/*
+** This following structure defines all the methods for the
+** stmt virtual table.
+*/
+static sqlite3_module stmtModule = {
+  0,                         /* iVersion */
+  0,                         /* xCreate */
+  stmtConnect,               /* xConnect */
+  stmtBestIndex,             /* xBestIndex */
+  stmtDisconnect,            /* xDisconnect */
+  0,                         /* xDestroy */
+  stmtOpen,                  /* xOpen - open a cursor */
+  stmtClose,                 /* xClose - close a cursor */
+  stmtFilter,                /* xFilter - configure scan constraints */
+  stmtNext,                  /* xNext - advance a cursor */
+  stmtEof,                   /* xEof - check for end of scan */
+  stmtColumn,                /* xColumn - read data */
+  stmtRowid,                 /* xRowid - read data */
+  0,                         /* xUpdate */
+  0,                         /* xBegin */
+  0,                         /* xSync */
+  0,                         /* xCommit */
+  0,                         /* xRollback */
+  0,                         /* xFindMethod */
+  0,                         /* xRename */
+  0,                         /* xSavepoint */
+  0,                         /* xRelease */
+  0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
+  0                          /* xIntegrity */
+};
+
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+SQLITE_PRIVATE int sqlite3StmtVtabInit(sqlite3 *db){
+  int rc = SQLITE_OK;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  rc = sqlite3_create_module(db, "sqlite_stmt", &stmtModule, 0);
+#endif
+  return rc;
+}
+
+#ifndef SQLITE_CORE
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_stmt_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  int rc = SQLITE_OK;
+  SQLITE_EXTENSION_INIT2(pApi);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  rc = sqlite3StmtVtabInit(db);
+#endif
+  return rc;
+}
+#endif /* SQLITE_CORE */
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_STMTVTAB) */
+
+/************** End of stmt.c ************************************************/
+/* Return the source-id for this library */
+SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
+#endif /* SQLITE_AMALGAMATION */
+/************************** End of sqlite3.c ******************************/
diff --git a/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3/sqlite3.h b/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3/sqlite3.h
new file mode 100644
index 0000000..b536f64
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3/sqlite3.h
@@ -0,0 +1,13715 @@
+/*
+** 2001-09-15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the SQLite library
+** presents to client programs.  If a C-function, structure, datatype,
+** or constant definition does not appear in this file, then it is
+** not a published API of SQLite, is subject to change without
+** notice, and should not be referenced by programs that use SQLite.
+**
+** Some of the definitions that are in this file are marked as
+** "experimental".  Experimental interfaces are normally new
+** features recently added to SQLite.  We do not anticipate changes
+** to experimental interfaces but reserve the right to make minor changes
+** if experience from use "in the wild" suggest such changes are prudent.
+**
+** The official C-language API documentation for SQLite is derived
+** from comments in this file.  This file is the authoritative source
+** on how SQLite interfaces are supposed to operate.
+**
+** The name of this file under configuration management is "sqlite.h.in".
+** The makefile makes some minor changes to this file (such as inserting
+** the version number) and changes its name to "sqlite3.h" as
+** part of the build process.
+*/
+#ifndef SQLITE3_H
+#define SQLITE3_H
+#include <stdarg.h>     /* Needed for the definition of va_list */
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/*
+** Facilitate override of interface linkage and calling conventions.
+** Be aware that these macros may not be used within this particular
+** translation of the amalgamation and its associated header file.
+**
+** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
+** compiler that the target identifier should have external linkage.
+**
+** The SQLITE_CDECL macro is used to set the calling convention for
+** public functions that accept a variable number of arguments.
+**
+** The SQLITE_APICALL macro is used to set the calling convention for
+** public functions that accept a fixed number of arguments.
+**
+** The SQLITE_STDCALL macro is no longer used and is now deprecated.
+**
+** The SQLITE_CALLBACK macro is used to set the calling convention for
+** function pointers.
+**
+** The SQLITE_SYSAPI macro is used to set the calling convention for
+** functions provided by the operating system.
+**
+** Currently, the SQLITE_CDECL, SQLITE_APICALL, SQLITE_CALLBACK, and
+** SQLITE_SYSAPI macros are used only when building for environments
+** that require non-default calling conventions.
+*/
+#ifndef SQLITE_EXTERN
+# define SQLITE_EXTERN extern
+#endif
+#ifndef SQLITE_API
+# define SQLITE_API
+#endif
+#ifndef SQLITE_CDECL
+# define SQLITE_CDECL
+#endif
+#ifndef SQLITE_APICALL
+# define SQLITE_APICALL
+#endif
+#ifndef SQLITE_STDCALL
+# define SQLITE_STDCALL SQLITE_APICALL
+#endif
+#ifndef SQLITE_CALLBACK
+# define SQLITE_CALLBACK
+#endif
+#ifndef SQLITE_SYSAPI
+# define SQLITE_SYSAPI
+#endif
+
+/*
+** These no-op macros are used in front of interfaces to mark those
+** interfaces as either deprecated or experimental.  New applications
+** should not use deprecated interfaces - they are supported for backwards
+** compatibility only.  Application writers should be aware that
+** experimental interfaces are subject to change in point releases.
+**
+** These macros used to resolve to various kinds of compiler magic that
+** would generate warning messages when they were used.  But that
+** compiler magic ended up generating such a flurry of bug reports
+** that we have taken it all out and gone back to using simple
+** noop macros.
+*/
+#define SQLITE_DEPRECATED
+#define SQLITE_EXPERIMENTAL
+
+/*
+** Ensure these symbols were not defined by some previous header file.
+*/
+#ifdef SQLITE_VERSION
+# undef SQLITE_VERSION
+#endif
+#ifdef SQLITE_VERSION_NUMBER
+# undef SQLITE_VERSION_NUMBER
+#endif
+
+/*
+** CAPI3REF: Compile-Time Library Version Numbers
+**
+** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
+** evaluates to a string literal that is the SQLite version in the
+** format "X.Y.Z" where X is the major version number (always 3 for
+** SQLite3) and Y is the minor version number and Z is the release number.)^
+** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
+** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
+** numbers used in [SQLITE_VERSION].)^
+** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
+** be larger than the release from which it is derived.  Either Y will
+** be held constant and Z will be incremented or else Y will be incremented
+** and Z will be reset to zero.
+**
+** Since [version 3.6.18] ([dateof:3.6.18]),
+** SQLite source code has been stored in the
+** <a href="http://www.fossil-scm.org/">Fossil configuration management
+** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
+** a string which identifies a particular check-in of SQLite
+** within its configuration management system.  ^The SQLITE_SOURCE_ID
+** string contains the date and time of the check-in (UTC) and a SHA1
+** or SHA3-256 hash of the entire source tree.  If the source code has
+** been edited in any way since it was last checked in, then the last
+** four hexadecimal digits of the hash may be modified.
+**
+** See also: [sqlite3_libversion()],
+** [sqlite3_libversion_number()], [sqlite3_sourceid()],
+** [sqlite_version()] and [sqlite_source_id()].
+*/
+#define SQLITE_VERSION        "3.49.2"
+#define SQLITE_VERSION_NUMBER 3049002
+#define SQLITE_SOURCE_ID      "2025-05-07 10:39:52 17144570b0d96ae63cd6f3edca39e27ebd74925252bbaf6723bcb2f6b4861fb1"
+
+/*
+** CAPI3REF: Run-Time Library Version Numbers
+** KEYWORDS: sqlite3_version sqlite3_sourceid
+**
+** These interfaces provide the same information as the [SQLITE_VERSION],
+** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
+** but are associated with the library instead of the header file.  ^(Cautious
+** programmers might include assert() statements in their application to
+** verify that values returned by these interfaces match the macros in
+** the header, and thus ensure that the application is
+** compiled with matching library and header files.
+**
+** <blockquote><pre>
+** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
+** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
+** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
+** </pre></blockquote>)^
+**
+** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
+** macro.  ^The sqlite3_libversion() function returns a pointer to the
+** to the sqlite3_version[] string constant.  The sqlite3_libversion()
+** function is provided for use in DLLs since DLL users usually do not have
+** direct access to string constants within the DLL.  ^The
+** sqlite3_libversion_number() function returns an integer equal to
+** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns
+** a pointer to a string constant whose value is the same as the
+** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
+** using an edited copy of [the amalgamation], then the last four characters
+** of the hash might be different from [SQLITE_SOURCE_ID].)^
+**
+** See also: [sqlite_version()] and [sqlite_source_id()].
+*/
+SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
+SQLITE_API const char *sqlite3_libversion(void);
+SQLITE_API const char *sqlite3_sourceid(void);
+SQLITE_API int sqlite3_libversion_number(void);
+
+/*
+** CAPI3REF: Run-Time Library Compilation Options Diagnostics
+**
+** ^The sqlite3_compileoption_used() function returns 0 or 1
+** indicating whether the specified option was defined at
+** compile time.  ^The SQLITE_ prefix may be omitted from the
+** option name passed to sqlite3_compileoption_used().
+**
+** ^The sqlite3_compileoption_get() function allows iterating
+** over the list of options that were defined at compile time by
+** returning the N-th compile time option string.  ^If N is out of range,
+** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
+** prefix is omitted from any strings returned by
+** sqlite3_compileoption_get().
+**
+** ^Support for the diagnostic functions sqlite3_compileoption_used()
+** and sqlite3_compileoption_get() may be omitted by specifying the
+** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
+**
+** See also: SQL functions [sqlite_compileoption_used()] and
+** [sqlite_compileoption_get()] and the [compile_options pragma].
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
+SQLITE_API const char *sqlite3_compileoption_get(int N);
+#else
+# define sqlite3_compileoption_used(X) 0
+# define sqlite3_compileoption_get(X)  ((void*)0)
+#endif
+
+/*
+** CAPI3REF: Test To See If The Library Is Threadsafe
+**
+** ^The sqlite3_threadsafe() function returns zero if and only if
+** SQLite was compiled with mutexing code omitted due to the
+** [SQLITE_THREADSAFE] compile-time option being set to 0.
+**
+** SQLite can be compiled with or without mutexes.  When
+** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
+** are enabled and SQLite is threadsafe.  When the
+** [SQLITE_THREADSAFE] macro is 0,
+** the mutexes are omitted.  Without the mutexes, it is not safe
+** to use SQLite concurrently from more than one thread.
+**
+** Enabling mutexes incurs a measurable performance penalty.
+** So if speed is of utmost importance, it makes sense to disable
+** the mutexes.  But for maximum safety, mutexes should be enabled.
+** ^The default behavior is for mutexes to be enabled.
+**
+** This interface can be used by an application to make sure that the
+** version of SQLite that it is linking against was compiled with
+** the desired setting of the [SQLITE_THREADSAFE] macro.
+**
+** This interface only reports on the compile-time mutex setting
+** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
+** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
+** can be fully or partially disabled using a call to [sqlite3_config()]
+** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
+** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
+** sqlite3_threadsafe() function shows only the compile-time setting of
+** thread safety, not any run-time changes to that setting made by
+** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
+** is unchanged by calls to sqlite3_config().)^
+**
+** See the [threading mode] documentation for additional information.
+*/
+SQLITE_API int sqlite3_threadsafe(void);
+
+/*
+** CAPI3REF: Database Connection Handle
+** KEYWORDS: {database connection} {database connections}
+**
+** Each open SQLite database is represented by a pointer to an instance of
+** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
+** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
+** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
+** and [sqlite3_close_v2()] are its destructors.  There are many other
+** interfaces (such as
+** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
+** [sqlite3_busy_timeout()] to name but three) that are methods on an
+** sqlite3 object.
+*/
+typedef struct sqlite3 sqlite3;
+
+/*
+** CAPI3REF: 64-Bit Integer Types
+** KEYWORDS: sqlite_int64 sqlite_uint64
+**
+** Because there is no cross-platform way to specify 64-bit integer types
+** SQLite includes typedefs for 64-bit signed and unsigned integers.
+**
+** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
+** The sqlite_int64 and sqlite_uint64 types are supported for backwards
+** compatibility only.
+**
+** ^The sqlite3_int64 and sqlite_int64 types can store integer values
+** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
+** sqlite3_uint64 and sqlite_uint64 types can store integer values
+** between 0 and +18446744073709551615 inclusive.
+*/
+#ifdef SQLITE_INT64_TYPE
+  typedef SQLITE_INT64_TYPE sqlite_int64;
+# ifdef SQLITE_UINT64_TYPE
+    typedef SQLITE_UINT64_TYPE sqlite_uint64;
+# else
+    typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
+# endif
+#elif defined(_MSC_VER) || defined(__BORLANDC__)
+  typedef __int64 sqlite_int64;
+  typedef unsigned __int64 sqlite_uint64;
+#else
+  typedef long long int sqlite_int64;
+  typedef unsigned long long int sqlite_uint64;
+#endif
+typedef sqlite_int64 sqlite3_int64;
+typedef sqlite_uint64 sqlite3_uint64;
+
+/*
+** If compiling for a processor that lacks floating point support,
+** substitute integer for floating-point.
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define double sqlite3_int64
+#endif
+
+/*
+** CAPI3REF: Closing A Database Connection
+** DESTRUCTOR: sqlite3
+**
+** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
+** for the [sqlite3] object.
+** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
+** the [sqlite3] object is successfully destroyed and all associated
+** resources are deallocated.
+**
+** Ideally, applications should [sqlite3_finalize | finalize] all
+** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
+** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
+** with the [sqlite3] object prior to attempting to close the object.
+** ^If the database connection is associated with unfinalized prepared
+** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
+** sqlite3_close() will leave the database connection open and return
+** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
+** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
+** it returns [SQLITE_OK] regardless, but instead of deallocating the database
+** connection immediately, it marks the database connection as an unusable
+** "zombie" and makes arrangements to automatically deallocate the database
+** connection after all prepared statements are finalized, all BLOB handles
+** are closed, and all backups have finished. The sqlite3_close_v2() interface
+** is intended for use with host languages that are garbage collected, and
+** where the order in which destructors are called is arbitrary.
+**
+** ^If an [sqlite3] object is destroyed while a transaction is open,
+** the transaction is automatically rolled back.
+**
+** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
+** must be either a NULL
+** pointer or an [sqlite3] object pointer obtained
+** from [sqlite3_open()], [sqlite3_open16()], or
+** [sqlite3_open_v2()], and not previously closed.
+** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
+** argument is a harmless no-op.
+*/
+SQLITE_API int sqlite3_close(sqlite3*);
+SQLITE_API int sqlite3_close_v2(sqlite3*);
+
+/*
+** The type for a callback function.
+** This is legacy and deprecated.  It is included for historical
+** compatibility and is not documented.
+*/
+typedef int (*sqlite3_callback)(void*,int,char**, char**);
+
+/*
+** CAPI3REF: One-Step Query Execution Interface
+** METHOD: sqlite3
+**
+** The sqlite3_exec() interface is a convenience wrapper around
+** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
+** that allows an application to run multiple statements of SQL
+** without having to use a lot of C code.
+**
+** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
+** semicolon-separate SQL statements passed into its 2nd argument,
+** in the context of the [database connection] passed in as its 1st
+** argument.  ^If the callback function of the 3rd argument to
+** sqlite3_exec() is not NULL, then it is invoked for each result row
+** coming out of the evaluated SQL statements.  ^The 4th argument to
+** sqlite3_exec() is relayed through to the 1st argument of each
+** callback invocation.  ^If the callback pointer to sqlite3_exec()
+** is NULL, then no callback is ever invoked and result rows are
+** ignored.
+**
+** ^If an error occurs while evaluating the SQL statements passed into
+** sqlite3_exec(), then execution of the current statement stops and
+** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
+** is not NULL then any error message is written into memory obtained
+** from [sqlite3_malloc()] and passed back through the 5th parameter.
+** To avoid memory leaks, the application should invoke [sqlite3_free()]
+** on error message strings returned through the 5th parameter of
+** sqlite3_exec() after the error message string is no longer needed.
+** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
+** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
+** NULL before returning.
+**
+** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
+** routine returns SQLITE_ABORT without invoking the callback again and
+** without running any subsequent SQL statements.
+**
+** ^The 2nd argument to the sqlite3_exec() callback function is the
+** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
+** callback is an array of pointers to strings obtained as if from
+** [sqlite3_column_text()], one for each column.  ^If an element of a
+** result row is NULL then the corresponding string pointer for the
+** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
+** sqlite3_exec() callback is an array of pointers to strings where each
+** entry represents the name of corresponding result column as obtained
+** from [sqlite3_column_name()].
+**
+** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
+** to an empty string, or a pointer that contains only whitespace and/or
+** SQL comments, then no SQL statements are evaluated and the database
+** is not changed.
+**
+** Restrictions:
+**
+** <ul>
+** <li> The application must ensure that the 1st parameter to sqlite3_exec()
+**      is a valid and open [database connection].
+** <li> The application must not close the [database connection] specified by
+**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not modify the SQL statement text passed into
+**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not dereference the arrays or string pointers
+**       passed as the 3rd and 4th callback parameters after it returns.
+** </ul>
+*/
+SQLITE_API int sqlite3_exec(
+  sqlite3*,                                  /* An open database */
+  const char *sql,                           /* SQL to be evaluated */
+  int (*callback)(void*,int,char**,char**),  /* Callback function */
+  void *,                                    /* 1st argument to callback */
+  char **errmsg                              /* Error msg written here */
+);
+
+/*
+** CAPI3REF: Result Codes
+** KEYWORDS: {result code definitions}
+**
+** Many SQLite functions return an integer result code from the set shown
+** here in order to indicate success or failure.
+**
+** New error codes may be added in future versions of SQLite.
+**
+** See also: [extended result code definitions]
+*/
+#define SQLITE_OK           0   /* Successful result */
+/* beginning-of-error-codes */
+#define SQLITE_ERROR        1   /* Generic error */
+#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
+#define SQLITE_PERM         3   /* Access permission denied */
+#define SQLITE_ABORT        4   /* Callback routine requested an abort */
+#define SQLITE_BUSY         5   /* The database file is locked */
+#define SQLITE_LOCKED       6   /* A table in the database is locked */
+#define SQLITE_NOMEM        7   /* A malloc() failed */
+#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
+#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
+#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
+#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
+#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
+#define SQLITE_FULL        13   /* Insertion failed because database is full */
+#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
+#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
+#define SQLITE_EMPTY       16   /* Internal use only */
+#define SQLITE_SCHEMA      17   /* The database schema changed */
+#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
+#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
+#define SQLITE_MISMATCH    20   /* Data type mismatch */
+#define SQLITE_MISUSE      21   /* Library used incorrectly */
+#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
+#define SQLITE_AUTH        23   /* Authorization denied */
+#define SQLITE_FORMAT      24   /* Not used */
+#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
+#define SQLITE_NOTADB      26   /* File opened that is not a database file */
+#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
+#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
+#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
+#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
+/* end-of-error-codes */
+
+/*
+** CAPI3REF: Extended Result Codes
+** KEYWORDS: {extended result code definitions}
+**
+** In its default configuration, SQLite API routines return one of 30 integer
+** [result codes].  However, experience has shown that many of
+** these result codes are too coarse-grained.  They do not provide as
+** much information about problems as programmers might like.  In an effort to
+** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
+** and later) include
+** support for additional result codes that provide more detailed information
+** about errors. These [extended result codes] are enabled or disabled
+** on a per database connection basis using the
+** [sqlite3_extended_result_codes()] API.  Or, the extended code for
+** the most recent error can be obtained using
+** [sqlite3_extended_errcode()].
+*/
+#define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
+#define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
+#define SQLITE_ERROR_SNAPSHOT          (SQLITE_ERROR | (3<<8))
+#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
+#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
+#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
+#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
+#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
+#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
+#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
+#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
+#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
+#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
+#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
+#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
+#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
+#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
+#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
+#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
+#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
+#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
+#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
+#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
+#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
+#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
+#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
+#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
+#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
+#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
+#define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
+#define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
+#define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
+#define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
+#define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
+#define SQLITE_IOERR_DATA              (SQLITE_IOERR | (32<<8))
+#define SQLITE_IOERR_CORRUPTFS         (SQLITE_IOERR | (33<<8))
+#define SQLITE_IOERR_IN_PAGE           (SQLITE_IOERR | (34<<8))
+#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
+#define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
+#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
+#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
+#define SQLITE_BUSY_TIMEOUT            (SQLITE_BUSY   |  (3<<8))
+#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
+#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
+#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
+#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
+#define SQLITE_CANTOPEN_DIRTYWAL       (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
+#define SQLITE_CANTOPEN_SYMLINK        (SQLITE_CANTOPEN | (6<<8))
+#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
+#define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
+#define SQLITE_CORRUPT_INDEX           (SQLITE_CORRUPT | (3<<8))
+#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
+#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
+#define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
+#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
+#define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
+#define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
+#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
+#define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
+#define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
+#define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
+#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
+#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
+#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
+#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
+#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
+#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
+#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
+#define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
+#define SQLITE_CONSTRAINT_DATATYPE     (SQLITE_CONSTRAINT |(12<<8))
+#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
+#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
+#define SQLITE_NOTICE_RBU              (SQLITE_NOTICE | (3<<8))
+#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
+#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
+#define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
+#define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8)) /* internal use only */
+
+/*
+** CAPI3REF: Flags For File Open Operations
+**
+** These bit values are intended for use in the
+** 3rd parameter to the [sqlite3_open_v2()] interface and
+** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
+**
+** Only those flags marked as "Ok for sqlite3_open_v2()" may be
+** used as the third argument to the [sqlite3_open_v2()] interface.
+** The other flags have historically been ignored by sqlite3_open_v2(),
+** though future versions of SQLite might change so that an error is
+** raised if any of the disallowed bits are passed into sqlite3_open_v2().
+** Applications should not depend on the historical behavior.
+**
+** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
+** [sqlite3_open_v2()] does *not* cause the underlying database file
+** to be opened using O_EXCL.  Passing SQLITE_OPEN_EXCLUSIVE into
+** [sqlite3_open_v2()] has historically be a no-op and might become an
+** error in future versions of SQLite.
+*/
+#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
+#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
+#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
+#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
+#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
+#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
+#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
+#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
+#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
+#define SQLITE_OPEN_SUPER_JOURNAL    0x00004000  /* VFS only */
+#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
+#define SQLITE_OPEN_NOFOLLOW         0x01000000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_EXRESCODE        0x02000000  /* Extended result codes */
+
+/* Reserved:                         0x00F00000 */
+/* Legacy compatibility: */
+#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
+
+
+/*
+** CAPI3REF: Device Characteristics
+**
+** The xDeviceCharacteristics method of the [sqlite3_io_methods]
+** object returns an integer which is a vector of these
+** bit values expressing I/O characteristics of the mass storage
+** device that holds the file that the [sqlite3_io_methods]
+** refers to.
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
+** after reboot following a crash or power loss, the only bytes in a
+** file that were written at the application level might have changed
+** and that adjacent bytes, even bytes within the same sector are
+** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
+** flag indicates that a file cannot be deleted when open.  The
+** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
+** read-only media and cannot be changed even by processes with
+** elevated privileges.
+**
+** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
+** filesystem supports doing multiple write operations atomically when those
+** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
+** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
+**
+** The SQLITE_IOCAP_SUBPAGE_READ property means that it is ok to read
+** from the database file in amounts that are not a multiple of the
+** page size and that do not begin at a page boundary.  Without this
+** property, SQLite is careful to only do full-page reads and write
+** on aligned pages, with the one exception that it will do a sub-page
+** read of the first page to access the database header.
+*/
+#define SQLITE_IOCAP_ATOMIC                 0x00000001
+#define SQLITE_IOCAP_ATOMIC512              0x00000002
+#define SQLITE_IOCAP_ATOMIC1K               0x00000004
+#define SQLITE_IOCAP_ATOMIC2K               0x00000008
+#define SQLITE_IOCAP_ATOMIC4K               0x00000010
+#define SQLITE_IOCAP_ATOMIC8K               0x00000020
+#define SQLITE_IOCAP_ATOMIC16K              0x00000040
+#define SQLITE_IOCAP_ATOMIC32K              0x00000080
+#define SQLITE_IOCAP_ATOMIC64K              0x00000100
+#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
+#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
+#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
+#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
+#define SQLITE_IOCAP_IMMUTABLE              0x00002000
+#define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
+#define SQLITE_IOCAP_SUBPAGE_READ           0x00008000
+
+/*
+** CAPI3REF: File Locking Levels
+**
+** SQLite uses one of these integer values as the second
+** argument to calls it makes to the xLock() and xUnlock() methods
+** of an [sqlite3_io_methods] object.  These values are ordered from
+** lest restrictive to most restrictive.
+**
+** The argument to xLock() is always SHARED or higher.  The argument to
+** xUnlock is either SHARED or NONE.
+*/
+#define SQLITE_LOCK_NONE          0       /* xUnlock() only */
+#define SQLITE_LOCK_SHARED        1       /* xLock() or xUnlock() */
+#define SQLITE_LOCK_RESERVED      2       /* xLock() only */
+#define SQLITE_LOCK_PENDING       3       /* xLock() only */
+#define SQLITE_LOCK_EXCLUSIVE     4       /* xLock() only */
+
+/*
+** CAPI3REF: Synchronization Type Flags
+**
+** When SQLite invokes the xSync() method of an
+** [sqlite3_io_methods] object it uses a combination of
+** these integer values as the second argument.
+**
+** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
+** sync operation only needs to flush data to mass storage.  Inode
+** information need not be flushed. If the lower four bits of the flag
+** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
+** If the lower four bits equal SQLITE_SYNC_FULL, that means
+** to use Mac OS X style fullsync instead of fsync().
+**
+** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
+** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
+** settings.  The [synchronous pragma] determines when calls to the
+** xSync VFS method occur and applies uniformly across all platforms.
+** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
+** energetic or rigorous or forceful the sync operations are and
+** only make a difference on Mac OSX for the default SQLite code.
+** (Third-party VFS implementations might also make the distinction
+** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
+** operating systems natively supported by SQLite, only Mac OSX
+** cares about the difference.)
+*/
+#define SQLITE_SYNC_NORMAL        0x00002
+#define SQLITE_SYNC_FULL          0x00003
+#define SQLITE_SYNC_DATAONLY      0x00010
+
+/*
+** CAPI3REF: OS Interface Open File Handle
+**
+** An [sqlite3_file] object represents an open file in the
+** [sqlite3_vfs | OS interface layer].  Individual OS interface
+** implementations will
+** want to subclass this object by appending additional fields
+** for their own use.  The pMethods entry is a pointer to an
+** [sqlite3_io_methods] object that defines methods for performing
+** I/O operations on the open file.
+*/
+typedef struct sqlite3_file sqlite3_file;
+struct sqlite3_file {
+  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
+};
+
+/*
+** CAPI3REF: OS Interface File Virtual Methods Object
+**
+** Every file opened by the [sqlite3_vfs.xOpen] method populates an
+** [sqlite3_file] object (or, more commonly, a subclass of the
+** [sqlite3_file] object) with a pointer to an instance of this object.
+** This object defines the methods used to perform various operations
+** against the open file represented by the [sqlite3_file] object.
+**
+** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
+** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
+** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
+** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
+** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
+** to NULL.
+**
+** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
+** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
+** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
+** flag may be ORed in to indicate that only the data of the file
+** and not its inode needs to be synced.
+**
+** The integer values to xLock() and xUnlock() are one of
+** <ul>
+** <li> [SQLITE_LOCK_NONE],
+** <li> [SQLITE_LOCK_SHARED],
+** <li> [SQLITE_LOCK_RESERVED],
+** <li> [SQLITE_LOCK_PENDING], or
+** <li> [SQLITE_LOCK_EXCLUSIVE].
+** </ul>
+** xLock() upgrades the database file lock.  In other words, xLock() moves the
+** database file lock in the direction NONE toward EXCLUSIVE. The argument to
+** xLock() is always one of SHARED, RESERVED, PENDING, or EXCLUSIVE, never
+** SQLITE_LOCK_NONE.  If the database file lock is already at or above the
+** requested lock, then the call to xLock() is a no-op.
+** xUnlock() downgrades the database file lock to either SHARED or NONE.
+** If the lock is already at or below the requested lock state, then the call
+** to xUnlock() is a no-op.
+** The xCheckReservedLock() method checks whether any database connection,
+** either in this process or in some other process, is holding a RESERVED,
+** PENDING, or EXCLUSIVE lock on the file.  It returns, via its output
+** pointer parameter, true if such a lock exists and false otherwise.
+**
+** The xFileControl() method is a generic interface that allows custom
+** VFS implementations to directly control an open file using the
+** [sqlite3_file_control()] interface.  The second "op" argument is an
+** integer opcode.  The third argument is a generic pointer intended to
+** point to a structure that may contain arguments or space in which to
+** write return values.  Potential uses for xFileControl() might be
+** functions to enable blocking locks with timeouts, to change the
+** locking strategy (for example to use dot-file locks), to inquire
+** about the status of a lock, or to break stale locks.  The SQLite
+** core reserves all opcodes less than 100 for its own use.
+** A [file control opcodes | list of opcodes] less than 100 is available.
+** Applications that define a custom xFileControl method should use opcodes
+** greater than 100 to avoid conflicts.  VFS implementations should
+** return [SQLITE_NOTFOUND] for file control opcodes that they do not
+** recognize.
+**
+** The xSectorSize() method returns the sector size of the
+** device that underlies the file.  The sector size is the
+** minimum write that can be performed without disturbing
+** other bytes in the file.  The xDeviceCharacteristics()
+** method returns a bit vector describing behaviors of the
+** underlying device:
+**
+** <ul>
+** <li> [SQLITE_IOCAP_ATOMIC]
+** <li> [SQLITE_IOCAP_ATOMIC512]
+** <li> [SQLITE_IOCAP_ATOMIC1K]
+** <li> [SQLITE_IOCAP_ATOMIC2K]
+** <li> [SQLITE_IOCAP_ATOMIC4K]
+** <li> [SQLITE_IOCAP_ATOMIC8K]
+** <li> [SQLITE_IOCAP_ATOMIC16K]
+** <li> [SQLITE_IOCAP_ATOMIC32K]
+** <li> [SQLITE_IOCAP_ATOMIC64K]
+** <li> [SQLITE_IOCAP_SAFE_APPEND]
+** <li> [SQLITE_IOCAP_SEQUENTIAL]
+** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
+** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
+** <li> [SQLITE_IOCAP_IMMUTABLE]
+** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
+** <li> [SQLITE_IOCAP_SUBPAGE_READ]
+** </ul>
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().
+**
+** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
+** in the unread portions of the buffer with zeros.  A VFS that
+** fails to zero-fill short reads might seem to work.  However,
+** failure to zero-fill short reads will eventually lead to
+** database corruption.
+*/
+typedef struct sqlite3_io_methods sqlite3_io_methods;
+struct sqlite3_io_methods {
+  int iVersion;
+  int (*xClose)(sqlite3_file*);
+  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
+  int (*xSync)(sqlite3_file*, int flags);
+  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
+  int (*xLock)(sqlite3_file*, int);
+  int (*xUnlock)(sqlite3_file*, int);
+  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
+  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
+  int (*xSectorSize)(sqlite3_file*);
+  int (*xDeviceCharacteristics)(sqlite3_file*);
+  /* Methods above are valid for version 1 */
+  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
+  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
+  void (*xShmBarrier)(sqlite3_file*);
+  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
+  /* Methods above are valid for version 2 */
+  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
+  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
+  /* Methods above are valid for version 3 */
+  /* Additional methods may be added in future releases */
+};
+
+/*
+** CAPI3REF: Standard File Control Opcodes
+** KEYWORDS: {file control opcodes} {file control opcode}
+**
+** These integer constants are opcodes for the xFileControl method
+** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
+** interface.
+**
+** <ul>
+** <li>[[SQLITE_FCNTL_LOCKSTATE]]
+** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
+** opcode causes the xFileControl method to write the current state of
+** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
+** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
+** into an integer that the pArg argument points to.
+** This capability is only available if SQLite is compiled with [SQLITE_DEBUG].
+**
+** <li>[[SQLITE_FCNTL_SIZE_HINT]]
+** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
+** layer a hint of how large the database file will grow to be during the
+** current transaction.  This hint is not guaranteed to be accurate but it
+** is often close.  The underlying VFS might choose to preallocate database
+** file space based on this hint in order to help writes to the database
+** file run faster.
+**
+** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
+** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
+** implements [sqlite3_deserialize()] to set an upper bound on the size
+** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
+** If the integer pointed to is negative, then it is filled in with the
+** current limit.  Otherwise the limit is set to the larger of the value
+** of the integer pointed to and the current database size.  The integer
+** pointed to is set to the new limit.
+**
+** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
+** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
+** extends and truncates the database file in chunks of a size specified
+** by the user. The fourth argument to [sqlite3_file_control()] should
+** point to an integer (type int) containing the new chunk-size to use
+** for the nominated database. Allocating database file space in large
+** chunks (say 1MB at a time), may reduce file-system fragmentation and
+** improve performance on some systems.
+**
+** <li>[[SQLITE_FCNTL_FILE_POINTER]]
+** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with a particular database
+** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
+**
+** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
+** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with the journal file (either
+** the [rollback journal] or the [write-ahead log]) for a particular database
+** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
+**
+** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
+** No longer in use.
+**
+** <li>[[SQLITE_FCNTL_SYNC]]
+** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
+** sent to the VFS immediately before the xSync method is invoked on a
+** database file descriptor. Or, if the xSync method is not invoked
+** because the user has configured SQLite with
+** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
+** of the xSync method. In most cases, the pointer argument passed with
+** this file-control is NULL. However, if the database file is being synced
+** as part of a multi-database commit, the argument points to a nul-terminated
+** string containing the transactions super-journal file name. VFSes that
+** do not need this signal should silently ignore this opcode. Applications
+** should not call [sqlite3_file_control()] with this opcode as doing so may
+** disrupt the operation of the specialized VFSes that do require it.
+**
+** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
+** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
+** and sent to the VFS after a transaction has been committed immediately
+** but before the database is unlocked. VFSes that do not need this signal
+** should silently ignore this opcode. Applications should not call
+** [sqlite3_file_control()] with this opcode as doing so may disrupt the
+** operation of the specialized VFSes that do require it.
+**
+** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
+** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
+** retry counts and intervals for certain disk I/O operations for the
+** windows [VFS] in order to provide robustness in the presence of
+** anti-virus programs.  By default, the windows VFS will retry file read,
+** file write, and file delete operations up to 10 times, with a delay
+** of 25 milliseconds before the first retry and with the delay increasing
+** by an additional 25 milliseconds with each subsequent retry.  This
+** opcode allows these two values (10 retries and 25 milliseconds of delay)
+** to be adjusted.  The values are changed for all database connections
+** within the same process.  The argument is a pointer to an array of two
+** integers where the first integer is the new retry count and the second
+** integer is the delay.  If either integer is negative, then the setting
+** is not changed but instead the prior value of that setting is written
+** into the array entry, allowing the current retry settings to be
+** interrogated.  The zDbName parameter is ignored.
+**
+** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
+** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
+** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
+** write ahead log ([WAL file]) and shared memory
+** files used for transaction control
+** are automatically deleted when the latest connection to the database
+** closes.  Setting persistent WAL mode causes those files to persist after
+** close.  Persisting the files is useful when other processes that do not
+** have write permission on the directory containing the database file want
+** to read the database file, as the WAL and shared memory files must exist
+** in order for the database to be readable.  The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
+** WAL mode.  If the integer is -1, then it is overwritten with the current
+** WAL persistence setting.
+**
+** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
+** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
+** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
+** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
+** xDeviceCharacteristics methods. The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
+** mode.  If the integer is -1, then it is overwritten with the current
+** zero-damage mode setting.
+**
+** <li>[[SQLITE_FCNTL_OVERWRITE]]
+** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
+** a write transaction to indicate that, unless it is rolled back for some
+** reason, the entire database file will be overwritten by the current
+** transaction. This is used by VACUUM operations.
+**
+** <li>[[SQLITE_FCNTL_VFSNAME]]
+** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
+** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
+** final bottom-level VFS are written into memory obtained from
+** [sqlite3_malloc()] and the result is stored in the char* variable
+** that the fourth parameter of [sqlite3_file_control()] points to.
+** The caller is responsible for freeing the memory when done.  As with
+** all file-control actions, there is no guarantee that this will actually
+** do anything.  Callers should initialize the char* variable to a NULL
+** pointer in case this file-control is not implemented.  This file-control
+** is intended for diagnostic use only.
+**
+** <li>[[SQLITE_FCNTL_VFS_POINTER]]
+** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
+** [VFSes] currently in use.  ^(The argument X in
+** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
+** of type "[sqlite3_vfs] **".  This opcodes will set *X
+** to a pointer to the top-level VFS.)^
+** ^When there are multiple VFS shims in the stack, this opcode finds the
+** upper-most shim only.
+**
+** <li>[[SQLITE_FCNTL_PRAGMA]]
+** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
+** file control is sent to the open [sqlite3_file] object corresponding
+** to the database file to which the pragma statement refers. ^The argument
+** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
+** pointers to strings (char**) in which the second element of the array
+** is the name of the pragma and the third element is the argument to the
+** pragma or NULL if the pragma has no argument.  ^The handler for an
+** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
+** of the char** argument point to a string obtained from [sqlite3_mprintf()]
+** or the equivalent and that string will become the result of the pragma or
+** the error message if the pragma fails. ^If the
+** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
+** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
+** file control returns [SQLITE_OK], then the parser assumes that the
+** VFS has handled the PRAGMA itself and the parser generates a no-op
+** prepared statement if result string is NULL, or that returns a copy
+** of the result string if the string is non-NULL.
+** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
+** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
+** that the VFS encountered an error while handling the [PRAGMA] and the
+** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
+** file control occurs at the beginning of pragma statement analysis and so
+** it is able to override built-in [PRAGMA] statements.
+**
+** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
+** ^The [SQLITE_FCNTL_BUSYHANDLER]
+** file-control may be invoked by SQLite on the database file handle
+** shortly after it is opened in order to provide a custom VFS with access
+** to the connection's busy-handler callback. The argument is of type (void**)
+** - an array of two (void *) values. The first (void *) actually points
+** to a function of type (int (*)(void *)). In order to invoke the connection's
+** busy-handler, this function should be invoked with the second (void *) in
+** the array as the only argument. If it returns non-zero, then the operation
+** should be retried. If it returns zero, the custom VFS should abandon the
+** current operation.
+**
+** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
+** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
+** to have SQLite generate a
+** temporary filename using the same algorithm that is followed to generate
+** temporary filenames for TEMP tables and other internal uses.  The
+** argument should be a char** which will be filled with the filename
+** written into memory obtained from [sqlite3_malloc()].  The caller should
+** invoke [sqlite3_free()] on the result to avoid a memory leak.
+**
+** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
+** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
+** maximum number of bytes that will be used for memory-mapped I/O.
+** The argument is a pointer to a value of type sqlite3_int64 that
+** is an advisory maximum number of bytes in the file to memory map.  The
+** pointer is overwritten with the old value.  The limit is not changed if
+** the value originally pointed to is negative, and so the current limit
+** can be queried by passing in a pointer to a negative number.  This
+** file-control is used internally to implement [PRAGMA mmap_size].
+**
+** <li>[[SQLITE_FCNTL_TRACE]]
+** The [SQLITE_FCNTL_TRACE] file control provides advisory information
+** to the VFS about what the higher layers of the SQLite stack are doing.
+** This file control is used by some VFS activity tracing [shims].
+** The argument is a zero-terminated string.  Higher layers in the
+** SQLite stack may generate instances of this file control if
+** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
+**
+** <li>[[SQLITE_FCNTL_HAS_MOVED]]
+** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
+** pointer to an integer and it writes a boolean into that integer depending
+** on whether or not the file has been renamed, moved, or deleted since it
+** was first opened.
+**
+** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
+** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
+** underlying native file handle associated with a file handle.  This file
+** control interprets its argument as a pointer to a native file handle and
+** writes the resulting value there.
+**
+** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
+** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
+** opcode causes the xFileControl method to swap the file handle with the one
+** pointed to by the pArg argument.  This capability is used during testing
+** and only needs to be supported when SQLITE_TEST is defined.
+**
+** <li>[[SQLITE_FCNTL_NULL_IO]]
+** The [SQLITE_FCNTL_NULL_IO] opcode sets the low-level file descriptor
+** or file handle for the [sqlite3_file] object such that it will no longer
+** read or write to the database file.
+**
+** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
+** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
+** be advantageous to block on the next WAL lock if the lock is not immediately
+** available.  The WAL subsystem issues this signal during rare
+** circumstances in order to fix a problem with priority inversion.
+** Applications should <em>not</em> use this file-control.
+**
+** <li>[[SQLITE_FCNTL_ZIPVFS]]
+** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
+** VFS should return SQLITE_NOTFOUND for this opcode.
+**
+** <li>[[SQLITE_FCNTL_RBU]]
+** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
+** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
+** this opcode.
+**
+** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
+** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
+** the file descriptor is placed in "batch write mode", which
+** means all subsequent write operations will be deferred and done
+** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
+** that do not support batch atomic writes will return SQLITE_NOTFOUND.
+** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
+** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
+** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
+** no VFS interface calls on the same [sqlite3_file] file descriptor
+** except for calls to the xWrite method and the xFileControl method
+** with [SQLITE_FCNTL_SIZE_HINT].
+**
+** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
+** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
+** operations since the previous successful call to
+** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
+** This file control returns [SQLITE_OK] if and only if the writes were
+** all performed successfully and have been committed to persistent storage.
+** ^Regardless of whether or not it is successful, this file control takes
+** the file descriptor out of batch write mode so that all subsequent
+** write operations are independent.
+** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
+** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
+**
+** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
+** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
+** operations since the previous successful call to
+** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
+** ^This file control takes the file descriptor out of batch write mode
+** so that all subsequent write operations are independent.
+** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
+** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
+**
+** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
+** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
+** to block for up to M milliseconds before failing when attempting to
+** obtain a file lock using the xLock or xShmLock methods of the VFS.
+** The parameter is a pointer to a 32-bit signed integer that contains
+** the value that M is to be set to. Before returning, the 32-bit signed
+** integer is overwritten with the previous value of M.
+**
+** <li>[[SQLITE_FCNTL_DATA_VERSION]]
+** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
+** a database file.  The argument is a pointer to a 32-bit unsigned integer.
+** The "data version" for the pager is written into the pointer.  The
+** "data version" changes whenever any change occurs to the corresponding
+** database file, either through SQL statements on the same database
+** connection or through transactions committed by separate database
+** connections possibly in other processes. The [sqlite3_total_changes()]
+** interface can be used to find if any database on the connection has changed,
+** but that interface responds to changes on TEMP as well as MAIN and does
+** not provide a mechanism to detect changes to MAIN only.  Also, the
+** [sqlite3_total_changes()] interface responds to internal changes only and
+** omits changes made by other database connections.  The
+** [PRAGMA data_version] command provides a mechanism to detect changes to
+** a single attached database that occur due to other database connections,
+** but omits changes implemented by the database connection on which it is
+** called.  This file control is the only mechanism to detect changes that
+** happen either internally or externally and that are associated with
+** a particular attached database.
+**
+** <li>[[SQLITE_FCNTL_CKPT_START]]
+** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
+** in wal mode before the client starts to copy pages from the wal
+** file to the database file.
+**
+** <li>[[SQLITE_FCNTL_CKPT_DONE]]
+** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
+** in wal mode after the client has finished copying pages from the wal
+** file to the database file, but before the *-shm file is updated to
+** record the fact that the pages have been checkpointed.
+**
+** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
+** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
+** whether or not there is a database client in another process with a wal-mode
+** transaction open on the database or not. It is only available on unix.The
+** (void*) argument passed with this file-control should be a pointer to a
+** value of type (int). The integer value is set to 1 if the database is a wal
+** mode database and there exists at least one client in another process that
+** currently has an SQL transaction open on the database. It is set to 0 if
+** the database is not a wal-mode db, or if there is no such connection in any
+** other process. This opcode cannot be used to detect transactions opened
+** by clients within the current process, only within other processes.
+**
+** <li>[[SQLITE_FCNTL_CKSM_FILE]]
+** The [SQLITE_FCNTL_CKSM_FILE] opcode is for use internally by the
+** [checksum VFS shim] only.
+**
+** <li>[[SQLITE_FCNTL_RESET_CACHE]]
+** If there is currently no transaction open on the database, and the
+** database is not a temp db, then the [SQLITE_FCNTL_RESET_CACHE] file-control
+** purges the contents of the in-memory page cache. If there is an open
+** transaction, or if the db is a temp-db, this opcode is a no-op, not an error.
+** </ul>
+*/
+#define SQLITE_FCNTL_LOCKSTATE               1
+#define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
+#define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
+#define SQLITE_FCNTL_LAST_ERRNO              4
+#define SQLITE_FCNTL_SIZE_HINT               5
+#define SQLITE_FCNTL_CHUNK_SIZE              6
+#define SQLITE_FCNTL_FILE_POINTER            7
+#define SQLITE_FCNTL_SYNC_OMITTED            8
+#define SQLITE_FCNTL_WIN32_AV_RETRY          9
+#define SQLITE_FCNTL_PERSIST_WAL            10
+#define SQLITE_FCNTL_OVERWRITE              11
+#define SQLITE_FCNTL_VFSNAME                12
+#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
+#define SQLITE_FCNTL_PRAGMA                 14
+#define SQLITE_FCNTL_BUSYHANDLER            15
+#define SQLITE_FCNTL_TEMPFILENAME           16
+#define SQLITE_FCNTL_MMAP_SIZE              18
+#define SQLITE_FCNTL_TRACE                  19
+#define SQLITE_FCNTL_HAS_MOVED              20
+#define SQLITE_FCNTL_SYNC                   21
+#define SQLITE_FCNTL_COMMIT_PHASETWO        22
+#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
+#define SQLITE_FCNTL_WAL_BLOCK              24
+#define SQLITE_FCNTL_ZIPVFS                 25
+#define SQLITE_FCNTL_RBU                    26
+#define SQLITE_FCNTL_VFS_POINTER            27
+#define SQLITE_FCNTL_JOURNAL_POINTER        28
+#define SQLITE_FCNTL_WIN32_GET_HANDLE       29
+#define SQLITE_FCNTL_PDB                    30
+#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
+#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
+#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
+#define SQLITE_FCNTL_LOCK_TIMEOUT           34
+#define SQLITE_FCNTL_DATA_VERSION           35
+#define SQLITE_FCNTL_SIZE_LIMIT             36
+#define SQLITE_FCNTL_CKPT_DONE              37
+#define SQLITE_FCNTL_RESERVE_BYTES          38
+#define SQLITE_FCNTL_CKPT_START             39
+#define SQLITE_FCNTL_EXTERNAL_READER        40
+#define SQLITE_FCNTL_CKSM_FILE              41
+#define SQLITE_FCNTL_RESET_CACHE            42
+#define SQLITE_FCNTL_NULL_IO                43
+
+/* deprecated names */
+#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
+#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
+#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
+
+
+/*
+** CAPI3REF: Mutex Handle
+**
+** The mutex module within SQLite defines [sqlite3_mutex] to be an
+** abstract type for a mutex object.  The SQLite core never looks
+** at the internal representation of an [sqlite3_mutex].  It only
+** deals with pointers to the [sqlite3_mutex] object.
+**
+** Mutexes are created using [sqlite3_mutex_alloc()].
+*/
+typedef struct sqlite3_mutex sqlite3_mutex;
+
+/*
+** CAPI3REF: Loadable Extension Thunk
+**
+** A pointer to the opaque sqlite3_api_routines structure is passed as
+** the third parameter to entry points of [loadable extensions].  This
+** structure must be typedefed in order to work around compiler warnings
+** on some platforms.
+*/
+typedef struct sqlite3_api_routines sqlite3_api_routines;
+
+/*
+** CAPI3REF: File Name
+**
+** Type [sqlite3_filename] is used by SQLite to pass filenames to the
+** xOpen method of a [VFS]. It may be cast to (const char*) and treated
+** as a normal, nul-terminated, UTF-8 buffer containing the filename, but
+** may also be passed to special APIs such as:
+**
+** <ul>
+** <li>  sqlite3_filename_database()
+** <li>  sqlite3_filename_journal()
+** <li>  sqlite3_filename_wal()
+** <li>  sqlite3_uri_parameter()
+** <li>  sqlite3_uri_boolean()
+** <li>  sqlite3_uri_int64()
+** <li>  sqlite3_uri_key()
+** </ul>
+*/
+typedef const char *sqlite3_filename;
+
+/*
+** CAPI3REF: OS Interface Object
+**
+** An instance of the sqlite3_vfs object defines the interface between
+** the SQLite core and the underlying operating system.  The "vfs"
+** in the name of the object stands for "virtual file system".  See
+** the [VFS | VFS documentation] for further information.
+**
+** The VFS interface is sometimes extended by adding new methods onto
+** the end.  Each time such an extension occurs, the iVersion field
+** is incremented.  The iVersion value started out as 1 in
+** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
+** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
+** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
+** may be appended to the sqlite3_vfs object and the iVersion value
+** may increase again in future versions of SQLite.
+** Note that due to an oversight, the structure
+** of the sqlite3_vfs object changed in the transition from
+** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
+** and yet the iVersion field was not increased.
+**
+** The szOsFile field is the size of the subclassed [sqlite3_file]
+** structure used by this VFS.  mxPathname is the maximum length of
+** a pathname in this VFS.
+**
+** Registered sqlite3_vfs objects are kept on a linked list formed by
+** the pNext pointer.  The [sqlite3_vfs_register()]
+** and [sqlite3_vfs_unregister()] interfaces manage this list
+** in a thread-safe way.  The [sqlite3_vfs_find()] interface
+** searches the list.  Neither the application code nor the VFS
+** implementation should use the pNext pointer.
+**
+** The pNext field is the only field in the sqlite3_vfs
+** structure that SQLite will ever modify.  SQLite will only access
+** or modify this field while holding a particular static mutex.
+** The application should never modify anything within the sqlite3_vfs
+** object once the object has been registered.
+**
+** The zName field holds the name of the VFS module.  The name must
+** be unique across all VFS modules.
+**
+** [[sqlite3_vfs.xOpen]]
+** ^SQLite guarantees that the zFilename parameter to xOpen
+** is either a NULL pointer or string obtained
+** from xFullPathname() with an optional suffix added.
+** ^If a suffix is added to the zFilename parameter, it will
+** consist of a single "-" character followed by no more than
+** 11 alphanumeric and/or "-" characters.
+** ^SQLite further guarantees that
+** the string will be valid and unchanged until xClose() is
+** called. Because of the previous sentence,
+** the [sqlite3_file] can safely store a pointer to the
+** filename if it needs to remember the filename for some reason.
+** If the zFilename parameter to xOpen is a NULL pointer then xOpen
+** must invent its own temporary name for the file.  ^Whenever the
+** xFilename parameter is NULL it will also be the case that the
+** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
+**
+** The flags argument to xOpen() includes all bits set in
+** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
+** or [sqlite3_open16()] is used, then flags includes at least
+** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
+** If xOpen() opens a file read-only then it sets *pOutFlags to
+** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
+**
+** ^(SQLite will also add one of the following flags to the xOpen()
+** call, depending on the object being opened:
+**
+** <ul>
+** <li>  [SQLITE_OPEN_MAIN_DB]
+** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
+** <li>  [SQLITE_OPEN_TEMP_DB]
+** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
+** <li>  [SQLITE_OPEN_TRANSIENT_DB]
+** <li>  [SQLITE_OPEN_SUBJOURNAL]
+** <li>  [SQLITE_OPEN_SUPER_JOURNAL]
+** <li>  [SQLITE_OPEN_WAL]
+** </ul>)^
+**
+** The file I/O implementation can use the object type flags to
+** change the way it deals with files.  For example, an application
+** that does not care about crash recovery or rollback might make
+** the open of a journal file a no-op.  Writes to this journal would
+** also be no-ops, and any attempt to read the journal would return
+** SQLITE_IOERR.  Or the implementation might recognize that a database
+** file will be doing page-aligned sector reads and writes in a random
+** order and set up its I/O subsystem accordingly.
+**
+** SQLite might also add one of the following flags to the xOpen method:
+**
+** <ul>
+** <li> [SQLITE_OPEN_DELETEONCLOSE]
+** <li> [SQLITE_OPEN_EXCLUSIVE]
+** </ul>
+**
+** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
+** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
+** will be set for TEMP databases and their journals, transient
+** databases, and subjournals.
+**
+** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
+** with the [SQLITE_OPEN_CREATE] flag, which are both directly
+** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
+** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
+** SQLITE_OPEN_CREATE, is used to indicate that file should always
+** be created, and that it is an error if it already exists.
+** It is <i>not</i> used to indicate the file should be opened
+** for exclusive access.
+**
+** ^At least szOsFile bytes of memory are allocated by SQLite
+** to hold the [sqlite3_file] structure passed as the third
+** argument to xOpen.  The xOpen method does not have to
+** allocate the structure; it should just fill it in.  Note that
+** the xOpen method must set the sqlite3_file.pMethods to either
+** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
+** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
+** element will be valid after xOpen returns regardless of the success
+** or failure of the xOpen call.
+**
+** [[sqlite3_vfs.xAccess]]
+** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
+** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
+** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
+** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
+** flag is never actually used and is not implemented in the built-in
+** VFSes of SQLite.  The file is named by the second argument and can be a
+** directory. The xAccess method returns [SQLITE_OK] on success or some
+** non-zero error code if there is an I/O error or if the name of
+** the file given in the second argument is illegal.  If SQLITE_OK
+** is returned, then non-zero or zero is written into *pResOut to indicate
+** whether or not the file is accessible.
+**
+** ^SQLite will always allocate at least mxPathname+1 bytes for the
+** output buffer xFullPathname.  The exact size of the output buffer
+** is also passed as a parameter to both  methods. If the output buffer
+** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
+** handled as a fatal error by SQLite, vfs implementations should endeavor
+** to prevent this by setting mxPathname to a sufficiently large value.
+**
+** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
+** interfaces are not strictly a part of the filesystem, but they are
+** included in the VFS structure for completeness.
+** The xRandomness() function attempts to return nBytes bytes
+** of good-quality randomness into zOut.  The return value is
+** the actual number of bytes of randomness obtained.
+** The xSleep() method causes the calling thread to sleep for at
+** least the number of microseconds given.  ^The xCurrentTime()
+** method returns a Julian Day Number for the current date and time as
+** a floating point value.
+** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
+** Day Number multiplied by 86400000 (the number of milliseconds in
+** a 24-hour day).
+** ^SQLite will use the xCurrentTimeInt64() method to get the current
+** date and time if that method is available (if iVersion is 2 or
+** greater and the function pointer is not NULL) and will fall back
+** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
+**
+** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
+** are not used by the SQLite core.  These optional interfaces are provided
+** by some VFSes to facilitate testing of the VFS code. By overriding
+** system calls with functions under its control, a test program can
+** simulate faults and error conditions that would otherwise be difficult
+** or impossible to induce.  The set of system calls that can be overridden
+** varies from one VFS to another, and from one version of the same VFS to the
+** next.  Applications that use these interfaces must be prepared for any
+** or all of these interfaces to be NULL or for their behavior to change
+** from one release to the next.  Applications must not attempt to access
+** any of these methods if the iVersion of the VFS is less than 3.
+*/
+typedef struct sqlite3_vfs sqlite3_vfs;
+typedef void (*sqlite3_syscall_ptr)(void);
+struct sqlite3_vfs {
+  int iVersion;            /* Structure version number (currently 3) */
+  int szOsFile;            /* Size of subclassed sqlite3_file */
+  int mxPathname;          /* Maximum file pathname length */
+  sqlite3_vfs *pNext;      /* Next registered VFS */
+  const char *zName;       /* Name of this virtual file system */
+  void *pAppData;          /* Pointer to application-specific data */
+  int (*xOpen)(sqlite3_vfs*, sqlite3_filename zName, sqlite3_file*,
+               int flags, int *pOutFlags);
+  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
+  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
+  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
+  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
+  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
+  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
+  void (*xDlClose)(sqlite3_vfs*, void*);
+  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
+  int (*xSleep)(sqlite3_vfs*, int microseconds);
+  int (*xCurrentTime)(sqlite3_vfs*, double*);
+  int (*xGetLastError)(sqlite3_vfs*, int, char *);
+  /*
+  ** The methods above are in version 1 of the sqlite_vfs object
+  ** definition.  Those that follow are added in version 2 or later
+  */
+  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
+  /*
+  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
+  ** Those below are for version 3 and greater.
+  */
+  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
+  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
+  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
+  /*
+  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
+  ** New fields may be appended in future versions.  The iVersion
+  ** value will increment whenever this happens.
+  */
+};
+
+/*
+** CAPI3REF: Flags for the xAccess VFS method
+**
+** These integer constants can be used as the third parameter to
+** the xAccess method of an [sqlite3_vfs] object.  They determine
+** what kind of permissions the xAccess method is looking for.
+** With SQLITE_ACCESS_EXISTS, the xAccess method
+** simply checks whether the file exists.
+** With SQLITE_ACCESS_READWRITE, the xAccess method
+** checks whether the named directory is both readable and writable
+** (in other words, if files can be added, removed, and renamed within
+** the directory).
+** The SQLITE_ACCESS_READWRITE constant is currently used only by the
+** [temp_store_directory pragma], though this could change in a future
+** release of SQLite.
+** With SQLITE_ACCESS_READ, the xAccess method
+** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
+** currently unused, though it might be used in a future release of
+** SQLite.
+*/
+#define SQLITE_ACCESS_EXISTS    0
+#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
+#define SQLITE_ACCESS_READ      2   /* Unused */
+
+/*
+** CAPI3REF: Flags for the xShmLock VFS method
+**
+** These integer constants define the various locking operations
+** allowed by the xShmLock method of [sqlite3_io_methods].  The
+** following are the only legal combinations of flags to the
+** xShmLock method:
+**
+** <ul>
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
+** </ul>
+**
+** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
+** was given on the corresponding lock.
+**
+** The xShmLock method can transition between unlocked and SHARED or
+** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
+** and EXCLUSIVE.
+*/
+#define SQLITE_SHM_UNLOCK       1
+#define SQLITE_SHM_LOCK         2
+#define SQLITE_SHM_SHARED       4
+#define SQLITE_SHM_EXCLUSIVE    8
+
+/*
+** CAPI3REF: Maximum xShmLock index
+**
+** The xShmLock method on [sqlite3_io_methods] may use values
+** between 0 and this upper bound as its "offset" argument.
+** The SQLite core will never attempt to acquire or release a
+** lock outside of this range
+*/
+#define SQLITE_SHM_NLOCK        8
+
+
+/*
+** CAPI3REF: Initialize The SQLite Library
+**
+** ^The sqlite3_initialize() routine initializes the
+** SQLite library.  ^The sqlite3_shutdown() routine
+** deallocates any resources that were allocated by sqlite3_initialize().
+** These routines are designed to aid in process initialization and
+** shutdown on embedded systems.  Workstation applications using
+** SQLite normally do not need to invoke either of these routines.
+**
+** A call to sqlite3_initialize() is an "effective" call if it is
+** the first time sqlite3_initialize() is invoked during the lifetime of
+** the process, or if it is the first time sqlite3_initialize() is invoked
+** following a call to sqlite3_shutdown().  ^(Only an effective call
+** of sqlite3_initialize() does any initialization.  All other calls
+** are harmless no-ops.)^
+**
+** A call to sqlite3_shutdown() is an "effective" call if it is the first
+** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
+** an effective call to sqlite3_shutdown() does any deinitialization.
+** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
+**
+** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
+** is not.  The sqlite3_shutdown() interface must only be called from a
+** single thread.  All open [database connections] must be closed and all
+** other SQLite resources must be deallocated prior to invoking
+** sqlite3_shutdown().
+**
+** Among other things, ^sqlite3_initialize() will invoke
+** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
+** will invoke sqlite3_os_end().
+**
+** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
+** ^If for some reason, sqlite3_initialize() is unable to initialize
+** the library (perhaps it is unable to allocate a needed resource such
+** as a mutex) it returns an [error code] other than [SQLITE_OK].
+**
+** ^The sqlite3_initialize() routine is called internally by many other
+** SQLite interfaces so that an application usually does not need to
+** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
+** calls sqlite3_initialize() so the SQLite library will be automatically
+** initialized when [sqlite3_open()] is called if it has not be initialized
+** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
+** compile-time option, then the automatic calls to sqlite3_initialize()
+** are omitted and the application must call sqlite3_initialize() directly
+** prior to using any other SQLite interface.  For maximum portability,
+** it is recommended that applications always invoke sqlite3_initialize()
+** directly prior to using any other SQLite interface.  Future releases
+** of SQLite may require this.  In other words, the behavior exhibited
+** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
+** default behavior in some future release of SQLite.
+**
+** The sqlite3_os_init() routine does operating-system specific
+** initialization of the SQLite library.  The sqlite3_os_end()
+** routine undoes the effect of sqlite3_os_init().  Typical tasks
+** performed by these routines include allocation or deallocation
+** of static resources, initialization of global variables,
+** setting up a default [sqlite3_vfs] module, or setting up
+** a default configuration using [sqlite3_config()].
+**
+** The application should never invoke either sqlite3_os_init()
+** or sqlite3_os_end() directly.  The application should only invoke
+** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
+** interface is called automatically by sqlite3_initialize() and
+** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
+** implementations for sqlite3_os_init() and sqlite3_os_end()
+** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
+** When [custom builds | built for other platforms]
+** (using the [SQLITE_OS_OTHER=1] compile-time
+** option) the application must supply a suitable implementation for
+** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
+** implementation of sqlite3_os_init() or sqlite3_os_end()
+** must return [SQLITE_OK] on success and some other [error code] upon
+** failure.
+*/
+SQLITE_API int sqlite3_initialize(void);
+SQLITE_API int sqlite3_shutdown(void);
+SQLITE_API int sqlite3_os_init(void);
+SQLITE_API int sqlite3_os_end(void);
+
+/*
+** CAPI3REF: Configuring The SQLite Library
+**
+** The sqlite3_config() interface is used to make global configuration
+** changes to SQLite in order to tune SQLite to the specific needs of
+** the application.  The default configuration is recommended for most
+** applications and so this routine is usually not necessary.  It is
+** provided to support rare applications with unusual needs.
+**
+** <b>The sqlite3_config() interface is not threadsafe. The application
+** must ensure that no other SQLite interfaces are invoked by other
+** threads while sqlite3_config() is running.</b>
+**
+** The first argument to sqlite3_config() is an integer
+** [configuration option] that determines
+** what property of SQLite is to be configured.  Subsequent arguments
+** vary depending on the [configuration option]
+** in the first argument.
+**
+** For most configuration options, the sqlite3_config() interface
+** may only be invoked prior to library initialization using
+** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
+** The exceptional configuration options that may be invoked at any time
+** are called "anytime configuration options".
+** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
+** [sqlite3_shutdown()] with a first argument that is not an anytime
+** configuration option, then the sqlite3_config() call will return SQLITE_MISUSE.
+** Note, however, that ^sqlite3_config() can be called as part of the
+** implementation of an application-defined [sqlite3_os_init()].
+**
+** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
+** ^If the option is unknown or SQLite is unable to set the option
+** then this routine returns a non-zero [error code].
+*/
+SQLITE_API int sqlite3_config(int, ...);
+
+/*
+** CAPI3REF: Configure database connections
+** METHOD: sqlite3
+**
+** The sqlite3_db_config() interface is used to make configuration
+** changes to a [database connection].  The interface is similar to
+** [sqlite3_config()] except that the changes apply to a single
+** [database connection] (specified in the first argument).
+**
+** The second argument to sqlite3_db_config(D,V,...)  is the
+** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
+** that indicates what aspect of the [database connection] is being configured.
+** Subsequent arguments vary depending on the configuration verb.
+**
+** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
+** the call is considered successful.
+*/
+SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Memory Allocation Routines
+**
+** An instance of this object defines the interface between SQLite
+** and low-level memory allocation routines.
+**
+** This object is used in only one place in the SQLite interface.
+** A pointer to an instance of this object is the argument to
+** [sqlite3_config()] when the configuration option is
+** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
+** By creating an instance of this object
+** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
+** during configuration, an application can specify an alternative
+** memory allocation subsystem for SQLite to use for all of its
+** dynamic memory needs.
+**
+** Note that SQLite comes with several [built-in memory allocators]
+** that are perfectly adequate for the overwhelming majority of applications
+** and that this object is only useful to a tiny minority of applications
+** with specialized memory allocation requirements.  This object is
+** also used during testing of SQLite in order to specify an alternative
+** memory allocator that simulates memory out-of-memory conditions in
+** order to verify that SQLite recovers gracefully from such
+** conditions.
+**
+** The xMalloc, xRealloc, and xFree methods must work like the
+** malloc(), realloc() and free() functions from the standard C library.
+** ^SQLite guarantees that the second argument to
+** xRealloc is always a value returned by a prior call to xRoundup.
+**
+** xSize should return the allocated size of a memory allocation
+** previously obtained from xMalloc or xRealloc.  The allocated size
+** is always at least as big as the requested size but may be larger.
+**
+** The xRoundup method returns what would be the allocated size of
+** a memory allocation given a particular requested size.  Most memory
+** allocators round up memory allocations at least to the next multiple
+** of 8.  Some allocators round up to a larger multiple or to a power of 2.
+** Every memory allocation request coming in through [sqlite3_malloc()]
+** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
+** that causes the corresponding memory allocation to fail.
+**
+** The xInit method initializes the memory allocator.  For example,
+** it might allocate any required mutexes or initialize internal data
+** structures.  The xShutdown method is invoked (indirectly) by
+** [sqlite3_shutdown()] and should deallocate any resources acquired
+** by xInit.  The pAppData pointer is used as the only parameter to
+** xInit and xShutdown.
+**
+** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
+** the xInit method, so the xInit method need not be threadsafe.  The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  For all other methods, SQLite
+** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
+** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
+** it is by default) and so the methods are automatically serialized.
+** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
+** methods must be threadsafe or else make their own arrangements for
+** serialization.
+**
+** SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+*/
+typedef struct sqlite3_mem_methods sqlite3_mem_methods;
+struct sqlite3_mem_methods {
+  void *(*xMalloc)(int);         /* Memory allocation function */
+  void (*xFree)(void*);          /* Free a prior allocation */
+  void *(*xRealloc)(void*,int);  /* Resize an allocation */
+  int (*xSize)(void*);           /* Return the size of an allocation */
+  int (*xRoundup)(int);          /* Round up request size to allocation size */
+  int (*xInit)(void*);           /* Initialize the memory allocator */
+  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
+  void *pAppData;                /* Argument to xInit() and xShutdown() */
+};
+
+/*
+** CAPI3REF: Configuration Options
+** KEYWORDS: {configuration option}
+**
+** These constants are the available integer configuration options that
+** can be passed as the first argument to the [sqlite3_config()] interface.
+**
+** Most of the configuration options for sqlite3_config()
+** will only work if invoked prior to [sqlite3_initialize()] or after
+** [sqlite3_shutdown()].  The few exceptions to this rule are called
+** "anytime configuration options".
+** ^Calling [sqlite3_config()] with a first argument that is not an
+** anytime configuration option in between calls to [sqlite3_initialize()] and
+** [sqlite3_shutdown()] is a no-op that returns SQLITE_MISUSE.
+**
+** The set of anytime configuration options can change (by insertions
+** and/or deletions) from one release of SQLite to the next.
+** As of SQLite version 3.42.0, the complete set of anytime configuration
+** options is:
+** <ul>
+** <li> SQLITE_CONFIG_LOG
+** <li> SQLITE_CONFIG_PCACHE_HDRSZ
+** </ul>
+**
+** New configuration options may be added in future releases of SQLite.
+** Existing configuration options might be discontinued.  Applications
+** should check the return code from [sqlite3_config()] to make sure that
+** the call worked.  The [sqlite3_config()] interface will return a
+** non-zero [error code] if a discontinued or unsupported configuration option
+** is invoked.
+**
+** <dl>
+** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Single-thread.  In other words, it disables
+** all mutexing and puts SQLite into a mode where it can only be used
+** by a single thread.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to change the [threading mode] from its default
+** value of Single-thread and so [sqlite3_config()] will return
+** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
+** configuration option.</dd>
+**
+** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Multi-thread.  In other words, it disables
+** mutexing on [database connection] and [prepared statement] objects.
+** The application is responsible for serializing access to
+** [database connections] and [prepared statements].  But other mutexes
+** are enabled so that SQLite will be safe to use in a multi-threaded
+** environment as long as no two threads attempt to use the same
+** [database connection] at the same time.  ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Multi-thread [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
+**
+** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Serialized. In other words, this option enables
+** all mutexes including the recursive
+** mutexes on [database connection] and [prepared statement] objects.
+** In this mode (which is the default when SQLite is compiled with
+** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
+** to [database connections] and [prepared statements] so that the
+** application is free to use the same [database connection] or the
+** same [prepared statement] in different threads at the same time.
+** ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Serialized [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
+**
+** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
+** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
+** a pointer to an instance of the [sqlite3_mem_methods] structure.
+** The argument specifies
+** alternative low-level memory allocation routines to be used in place of
+** the memory allocation routines built into SQLite.)^ ^SQLite makes
+** its own private copy of the content of the [sqlite3_mem_methods] structure
+** before the [sqlite3_config()] call returns.</dd>
+**
+** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
+** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
+** is a pointer to an instance of the [sqlite3_mem_methods] structure.
+** The [sqlite3_mem_methods]
+** structure is filled with the currently defined memory allocation routines.)^
+** This option can be used to overload the default memory allocation
+** routines with a wrapper that simulations memory allocation failure or
+** tracks memory usage, for example. </dd>
+**
+** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
+** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
+** type int, interpreted as a boolean, which if true provides a hint to
+** SQLite that it should avoid large memory allocations if possible.
+** SQLite will run faster if it is free to make large memory allocations,
+** but some application might prefer to run slower in exchange for
+** guarantees about memory fragmentation that are possible if large
+** allocations are avoided.  This hint is normally off.
+** </dd>
+**
+** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
+** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
+** interpreted as a boolean, which enables or disables the collection of
+** memory allocation statistics. ^(When memory allocation statistics are
+** disabled, the following SQLite interfaces become non-operational:
+**   <ul>
+**   <li> [sqlite3_hard_heap_limit64()]
+**   <li> [sqlite3_memory_used()]
+**   <li> [sqlite3_memory_highwater()]
+**   <li> [sqlite3_soft_heap_limit64()]
+**   <li> [sqlite3_status64()]
+**   </ul>)^
+** ^Memory allocation statistics are enabled by default unless SQLite is
+** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
+** allocation statistics are disabled by default.
+** </dd>
+**
+** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
+** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
+** </dd>
+**
+** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
+** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
+** that SQLite can use for the database page cache with the default page
+** cache implementation.
+** This configuration option is a no-op if an application-defined page
+** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
+** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
+** 8-byte aligned memory (pMem), the size of each page cache line (sz),
+** and the number of cache lines (N).
+** The sz argument should be the size of the largest database page
+** (a power of two between 512 and 65536) plus some extra bytes for each
+** page header.  ^The number of extra bytes needed by the page header
+** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
+** ^It is harmless, apart from the wasted memory,
+** for the sz parameter to be larger than necessary.  The pMem
+** argument must be either a NULL pointer or a pointer to an 8-byte
+** aligned block of memory of at least sz*N bytes, otherwise
+** subsequent behavior is undefined.
+** ^When pMem is not NULL, SQLite will strive to use the memory provided
+** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
+** a page cache line is larger than sz bytes or if all of the pMem buffer
+** is exhausted.
+** ^If pMem is NULL and N is non-zero, then each database connection
+** does an initial bulk allocation for page cache memory
+** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
+** of -1024*N bytes if N is negative, . ^If additional
+** page cache memory is needed beyond what is provided by the initial
+** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
+** additional cache line. </dd>
+**
+** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
+** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
+** that SQLite will use for all of its dynamic memory allocation needs
+** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
+** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
+** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
+** [SQLITE_ERROR] if invoked otherwise.
+** ^There are three arguments to SQLITE_CONFIG_HEAP:
+** An 8-byte aligned pointer to the memory,
+** the number of bytes in the memory buffer, and the minimum allocation size.
+** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
+** to using its default memory allocator (the system malloc() implementation),
+** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
+** memory pointer is not NULL then the alternative memory
+** allocator is engaged to handle all of SQLites memory allocation needs.
+** The first pointer (the memory pointer) must be aligned to an 8-byte
+** boundary or subsequent behavior of SQLite will be undefined.
+** The minimum allocation size is capped at 2**12. Reasonable values
+** for the minimum allocation size are 2**5 through 2**8.</dd>
+**
+** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
+** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
+** pointer to an instance of the [sqlite3_mutex_methods] structure.
+** The argument specifies alternative low-level mutex routines to be used
+** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
+** the content of the [sqlite3_mutex_methods] structure before the call to
+** [sqlite3_config()] returns. ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
+**
+** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
+** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
+** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
+** [sqlite3_mutex_methods]
+** structure is filled with the currently defined mutex routines.)^
+** This option can be used to overload the default mutex allocation
+** routines with a wrapper used to track mutex usage for performance
+** profiling or testing, for example.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
+**
+** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
+** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
+** the default size of lookaside memory on each [database connection].
+** The first argument is the
+** size of each lookaside buffer slot and the second is the number of
+** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
+** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
+** option to [sqlite3_db_config()] can be used to change the lookaside
+** configuration on individual connections.)^ </dd>
+**
+** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
+** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
+** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
+** the interface to a custom page cache implementation.)^
+** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
+**
+** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
+** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
+** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
+** the current page cache implementation into that object.)^ </dd>
+**
+** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
+** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
+** global [error log].
+** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
+** function with a call signature of void(*)(void*,int,const char*),
+** and a pointer to void. ^If the function pointer is not NULL, it is
+** invoked by [sqlite3_log()] to process each logging event.  ^If the
+** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
+** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
+** passed through as the first parameter to the application-defined logger
+** function whenever that function is invoked.  ^The second parameter to
+** the logger function is a copy of the first parameter to the corresponding
+** [sqlite3_log()] call and is intended to be a [result code] or an
+** [extended result code].  ^The third parameter passed to the logger is
+** log message after formatting via [sqlite3_snprintf()].
+** The SQLite logging interface is not reentrant; the logger function
+** supplied by the application must not invoke any SQLite interface.
+** In a multi-threaded application, the application-defined logger
+** function must be threadsafe. </dd>
+**
+** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
+** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
+** If non-zero, then URI handling is globally enabled. If the parameter is zero,
+** then URI handling is globally disabled.)^ ^If URI handling is globally
+** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
+** [sqlite3_open16()] or
+** specified as part of [ATTACH] commands are interpreted as URIs, regardless
+** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
+** connection is opened. ^If it is globally disabled, filenames are
+** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
+** database connection is opened. ^(By default, URI handling is globally
+** disabled. The default value may be changed by compiling with the
+** [SQLITE_USE_URI] symbol defined.)^
+**
+** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
+** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
+** argument which is interpreted as a boolean in order to enable or disable
+** the use of covering indices for full table scans in the query optimizer.
+** ^The default setting is determined
+** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
+** if that compile-time option is omitted.
+** The ability to disable the use of covering indices for full table scans
+** is because some incorrectly coded legacy applications might malfunction
+** when the optimization is enabled.  Providing the ability to
+** disable the optimization allows the older, buggy application code to work
+** without change even with newer versions of SQLite.
+**
+** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
+** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
+** <dd> These options are obsolete and should not be used by new code.
+** They are retained for backwards compatibility but are now no-ops.
+** </dd>
+**
+** [[SQLITE_CONFIG_SQLLOG]]
+** <dt>SQLITE_CONFIG_SQLLOG
+** <dd>This option is only available if sqlite is compiled with the
+** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
+** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
+** The second should be of type (void*). The callback is invoked by the library
+** in three separate circumstances, identified by the value passed as the
+** fourth parameter. If the fourth parameter is 0, then the database connection
+** passed as the second argument has just been opened. The third argument
+** points to a buffer containing the name of the main database file. If the
+** fourth parameter is 1, then the SQL statement that the third parameter
+** points to has just been executed. Or, if the fourth parameter is 2, then
+** the connection being passed as the second parameter is being closed. The
+** third parameter is passed NULL In this case.  An example of using this
+** configuration option can be seen in the "test_sqllog.c" source file in
+** the canonical SQLite source tree.</dd>
+**
+** [[SQLITE_CONFIG_MMAP_SIZE]]
+** <dt>SQLITE_CONFIG_MMAP_SIZE
+** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
+** that are the default mmap size limit (the default setting for
+** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
+** ^The default setting can be overridden by each database connection using
+** either the [PRAGMA mmap_size] command, or by using the
+** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
+** will be silently truncated if necessary so that it does not exceed the
+** compile-time maximum mmap size set by the
+** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
+** ^If either argument to this option is negative, then that argument is
+** changed to its compile-time default.
+**
+** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
+** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
+** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
+** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
+** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
+** that specifies the maximum size of the created heap.
+**
+** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
+** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
+** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
+** is a pointer to an integer and writes into that integer the number of extra
+** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
+** The amount of extra space required can change depending on the compiler,
+** target platform, and SQLite version.
+**
+** [[SQLITE_CONFIG_PMASZ]]
+** <dt>SQLITE_CONFIG_PMASZ
+** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
+** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
+** sorter to that integer.  The default minimum PMA Size is set by the
+** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
+** to help with sort operations when multithreaded sorting
+** is enabled (using the [PRAGMA threads] command) and the amount of content
+** to be sorted exceeds the page size times the minimum of the
+** [PRAGMA cache_size] setting and this value.
+**
+** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
+** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
+** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
+** becomes the [statement journal] spill-to-disk threshold.
+** [Statement journals] are held in memory until their size (in bytes)
+** exceeds this threshold, at which point they are written to disk.
+** Or if the threshold is -1, statement journals are always held
+** exclusively in memory.
+** Since many statement journals never become large, setting the spill
+** threshold to a value such as 64KiB can greatly reduce the amount of
+** I/O required to support statement rollback.
+** The default value for this setting is controlled by the
+** [SQLITE_STMTJRNL_SPILL] compile-time option.
+**
+** [[SQLITE_CONFIG_SORTERREF_SIZE]]
+** <dt>SQLITE_CONFIG_SORTERREF_SIZE
+** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
+** of type (int) - the new value of the sorter-reference size threshold.
+** Usually, when SQLite uses an external sort to order records according
+** to an ORDER BY clause, all fields required by the caller are present in the
+** sorted records. However, if SQLite determines based on the declared type
+** of a table column that its values are likely to be very large - larger
+** than the configured sorter-reference size threshold - then a reference
+** is stored in each sorted record and the required column values loaded
+** from the database as records are returned in sorted order. The default
+** value for this option is to never use this optimization. Specifying a
+** negative value for this option restores the default behavior.
+** This option is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
+**
+** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
+** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
+** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
+** [sqlite3_int64] parameter which is the default maximum size for an in-memory
+** database created using [sqlite3_deserialize()].  This default maximum
+** size can be adjusted up or down for individual databases using the
+** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
+** configuration setting is never used, then the default maximum is determined
+** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
+** compile-time option is not set, then the default maximum is 1073741824.
+**
+** [[SQLITE_CONFIG_ROWID_IN_VIEW]]
+** <dt>SQLITE_CONFIG_ROWID_IN_VIEW
+** <dd>The SQLITE_CONFIG_ROWID_IN_VIEW option enables or disables the ability
+** for VIEWs to have a ROWID.  The capability can only be enabled if SQLite is
+** compiled with -DSQLITE_ALLOW_ROWID_IN_VIEW, in which case the capability
+** defaults to on.  This configuration option queries the current setting or
+** changes the setting to off or on.  The argument is a pointer to an integer.
+** If that integer initially holds a value of 1, then the ability for VIEWs to
+** have ROWIDs is activated.  If the integer initially holds zero, then the
+** ability is deactivated.  Any other initial value for the integer leaves the
+** setting unchanged.  After changes, if any, the integer is written with
+** a 1 or 0, if the ability for VIEWs to have ROWIDs is on or off.  If SQLite
+** is compiled without -DSQLITE_ALLOW_ROWID_IN_VIEW (which is the usual and
+** recommended case) then the integer is always filled with zero, regardless
+** if its initial value.
+** </dl>
+*/
+#define SQLITE_CONFIG_SINGLETHREAD         1  /* nil */
+#define SQLITE_CONFIG_MULTITHREAD          2  /* nil */
+#define SQLITE_CONFIG_SERIALIZED           3  /* nil */
+#define SQLITE_CONFIG_MALLOC               4  /* sqlite3_mem_methods* */
+#define SQLITE_CONFIG_GETMALLOC            5  /* sqlite3_mem_methods* */
+#define SQLITE_CONFIG_SCRATCH              6  /* No longer used */
+#define SQLITE_CONFIG_PAGECACHE            7  /* void*, int sz, int N */
+#define SQLITE_CONFIG_HEAP                 8  /* void*, int nByte, int min */
+#define SQLITE_CONFIG_MEMSTATUS            9  /* boolean */
+#define SQLITE_CONFIG_MUTEX               10  /* sqlite3_mutex_methods* */
+#define SQLITE_CONFIG_GETMUTEX            11  /* sqlite3_mutex_methods* */
+/* previously SQLITE_CONFIG_CHUNKALLOC    12 which is now unused. */
+#define SQLITE_CONFIG_LOOKASIDE           13  /* int int */
+#define SQLITE_CONFIG_PCACHE              14  /* no-op */
+#define SQLITE_CONFIG_GETPCACHE           15  /* no-op */
+#define SQLITE_CONFIG_LOG                 16  /* xFunc, void* */
+#define SQLITE_CONFIG_URI                 17  /* int */
+#define SQLITE_CONFIG_PCACHE2             18  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_GETPCACHE2          19  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
+#define SQLITE_CONFIG_SQLLOG              21  /* xSqllog, void* */
+#define SQLITE_CONFIG_MMAP_SIZE           22  /* sqlite3_int64, sqlite3_int64 */
+#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
+#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
+#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
+#define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
+#define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
+#define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
+#define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
+#define SQLITE_CONFIG_ROWID_IN_VIEW       30  /* int* */
+
+/*
+** CAPI3REF: Database Connection Configuration Options
+**
+** These constants are the available integer configuration options that
+** can be passed as the second parameter to the [sqlite3_db_config()] interface.
+**
+** The [sqlite3_db_config()] interface is a var-args functions.  It takes a
+** variable number of parameters, though always at least two.  The number of
+** parameters passed into sqlite3_db_config() depends on which of these
+** constants is given as the second parameter.  This documentation page
+** refers to parameters beyond the second as "arguments".  Thus, when this
+** page says "the N-th argument" it means "the N-th parameter past the
+** configuration option" or "the (N+2)-th parameter to sqlite3_db_config()".
+**
+** New configuration options may be added in future releases of SQLite.
+** Existing configuration options might be discontinued.  Applications
+** should check the return code from [sqlite3_db_config()] to make sure that
+** the call worked.  ^The [sqlite3_db_config()] interface will return a
+** non-zero [error code] if a discontinued or unsupported configuration option
+** is invoked.
+**
+** <dl>
+** [[SQLITE_DBCONFIG_LOOKASIDE]]
+** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
+** <dd> The SQLITE_DBCONFIG_LOOKASIDE option is used to adjust the
+** configuration of the lookaside memory allocator within a database
+** connection.
+** The arguments to the SQLITE_DBCONFIG_LOOKASIDE option are <i>not</i>
+** in the [DBCONFIG arguments|usual format].
+** The SQLITE_DBCONFIG_LOOKASIDE option takes three arguments, not two,
+** so that a call to [sqlite3_db_config()] that uses SQLITE_DBCONFIG_LOOKASIDE
+** should have a total of five parameters.
+** ^The first argument (the third parameter to [sqlite3_db_config()] is a
+** pointer to a memory buffer to use for lookaside memory.
+** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
+** may be NULL in which case SQLite will allocate the
+** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
+** size of each lookaside buffer slot.  ^The third argument is the number of
+** slots.  The size of the buffer in the first argument must be greater than
+** or equal to the product of the second and third arguments.  The buffer
+** must be aligned to an 8-byte boundary.  ^If the second argument to
+** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
+** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
+** configuration for a database connection can only be changed when that
+** connection is not currently using lookaside memory, or in other words
+** when the "current value" returned by
+** [sqlite3_db_status](D,[SQLITE_DBSTATUS_LOOKASIDE_USED],...) is zero.
+** Any attempt to change the lookaside memory configuration when lookaside
+** memory is in use leaves the configuration unchanged and returns
+** [SQLITE_BUSY].)^</dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
+** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
+** <dd> ^This option is used to enable or disable the enforcement of
+** [foreign key constraints].  This is the same setting that is
+** enabled or disabled by the [PRAGMA foreign_keys] statement.
+** The first argument is an integer which is 0 to disable FK enforcement,
+** positive to enable FK enforcement or negative to leave FK enforcement
+** unchanged.  The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether FK enforcement is off or on
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the FK enforcement setting is not reported back. </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
+** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
+** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
+** There should be two additional arguments.
+** The first argument is an integer which is 0 to disable triggers,
+** positive to enable triggers or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether triggers are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the trigger setting is not reported back.
+**
+** <p>Originally this option disabled all triggers.  ^(However, since
+** SQLite version 3.35.0, TEMP triggers are still allowed even if
+** this option is off.  So, in other words, this option now only disables
+** triggers in the main database schema or in the schemas of [ATTACH]-ed
+** databases.)^ </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
+** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
+** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
+** There must be two additional arguments.
+** The first argument is an integer which is 0 to disable views,
+** positive to enable views or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether views are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the view setting is not reported back.
+**
+** <p>Originally this option disabled all views.  ^(However, since
+** SQLite version 3.35.0, TEMP views are still allowed even if
+** this option is off.  So, in other words, this option now only disables
+** views in the main database schema or in the schemas of ATTACH-ed
+** databases.)^ </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
+** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
+** <dd> ^This option is used to enable or disable the
+** [fts3_tokenizer()] function which is part of the
+** [FTS3] full-text search engine extension.
+** There must be two additional arguments.
+** The first argument is an integer which is 0 to disable fts3_tokenizer() or
+** positive to enable fts3_tokenizer() or negative to leave the setting
+** unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the new setting is not reported back. </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
+** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
+** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
+** interface independently of the [load_extension()] SQL function.
+** The [sqlite3_enable_load_extension()] API enables or disables both the
+** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
+** There must be two additional arguments.
+** When the first argument to this interface is 1, then only the C-API is
+** enabled and the SQL function remains disabled.  If the first argument to
+** this interface is 0, then both the C-API and the SQL function are disabled.
+** If the first argument is -1, then no changes are made to state of either the
+** C-API or the SQL function.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
+** is disabled or enabled following this call.  The second parameter may
+** be a NULL pointer, in which case the new setting is not reported back.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
+** <dd> ^This option is used to change the name of the "main" database
+** schema.  This option does not follow the
+** [DBCONFIG arguments|usual SQLITE_DBCONFIG argument format].
+** This option takes exactly one additional argument so that the
+** [sqlite3_db_config()] call has a total of three parameters.  The
+** extra argument must be a pointer to a constant UTF8 string which
+** will become the new schema name in place of "main".  ^SQLite does
+** not make a copy of the new main schema name string, so the application
+** must ensure that the argument passed into SQLITE_DBCONFIG MAINDBNAME
+** is unchanged until after the database connection closes.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
+** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
+** <dd> Usually, when a database in [WAL mode] is closed or detached from a
+** database handle, SQLite checks if if there are other connections to the
+** same database, and if there are no other database connection (if the
+** connection being closed is the last open connection to the database),
+** then SQLite performs a [checkpoint] before closing the connection and
+** deletes the WAL file.  The SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE option can
+** be used to override that behavior. The first argument passed to this
+** operation (the third parameter to [sqlite3_db_config()]) is an integer
+** which is positive to disable checkpoints-on-close, or zero (the default)
+** to enable them, and negative to leave the setting unchanged.
+** The second argument (the fourth parameter) is a pointer to an integer
+** into which is written 0 or 1 to indicate whether checkpoints-on-close
+** have been disabled - 0 if they are not disabled, 1 if they are.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
+** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
+** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
+** a single SQL query statement will always use the same algorithm regardless
+** of values of [bound parameters].)^ The QPSG disables some query optimizations
+** that look at the values of bound parameters, which can make some queries
+** slower.  But the QPSG has the advantage of more predictable behavior.  With
+** the QPSG active, SQLite will always use the same query plan in the field as
+** was used during testing in the lab.
+** The first argument to this setting is an integer which is 0 to disable
+** the QPSG, positive to enable QPSG, or negative to leave the setting
+** unchanged. The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
+** following this call.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
+** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
+** include output for any operations performed by trigger programs. This
+** option is used to set or clear (the default) a flag that governs this
+** behavior. The first parameter passed to this operation is an integer -
+** positive to enable output for trigger programs, or zero to disable it,
+** or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which is written
+** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
+** it is not disabled, 1 if it is.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
+** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
+** [VACUUM] in order to reset a database back to an empty database
+** with no schema and no content. The following process works even for
+** a badly corrupted database file:
+** <ol>
+** <li> If the database connection is newly opened, make sure it has read the
+**      database schema by preparing then discarding some query against the
+**      database, or calling sqlite3_table_column_metadata(), ignoring any
+**      errors.  This step is only necessary if the application desires to keep
+**      the database in WAL mode after the reset if it was in WAL mode before
+**      the reset.
+** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
+** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
+** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
+** </ol>
+** Because resetting a database is destructive and irreversible, the
+** process requires the use of this obscure API and multiple steps to
+** help ensure that it does not happen by accident. Because this
+** feature must be capable of resetting corrupt databases, and
+** shutting down virtual tables may require access to that corrupt
+** storage, the library must abandon any installed virtual tables
+** without calling their xDestroy() methods.
+**
+** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
+** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
+** "defensive" flag for a database connection.  When the defensive
+** flag is enabled, language features that allow ordinary SQL to
+** deliberately corrupt the database file are disabled.  The disabled
+** features include but are not limited to the following:
+** <ul>
+** <li> The [PRAGMA writable_schema=ON] statement.
+** <li> The [PRAGMA journal_mode=OFF] statement.
+** <li> The [PRAGMA schema_version=N] statement.
+** <li> Writes to the [sqlite_dbpage] virtual table.
+** <li> Direct writes to [shadow tables].
+** </ul>
+** </dd>
+**
+** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
+** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
+** "writable_schema" flag. This has the same effect and is logically equivalent
+** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
+** The first argument to this setting is an integer which is 0 to disable
+** the writable_schema, positive to enable writable_schema, or negative to
+** leave the setting unchanged. The second parameter is a pointer to an
+** integer into which is written 0 or 1 to indicate whether the writable_schema
+** is enabled or disabled following this call.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
+** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
+** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
+** the legacy behavior of the [ALTER TABLE RENAME] command such it
+** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
+** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
+** additional information. This feature can also be turned on and off
+** using the [PRAGMA legacy_alter_table] statement.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_DQS_DML]]
+** <dt>SQLITE_DBCONFIG_DQS_DML</dt>
+** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
+** the legacy [double-quoted string literal] misfeature for DML statements
+** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
+** default value of this setting is determined by the [-DSQLITE_DQS]
+** compile-time option.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_DQS_DDL]]
+** <dt>SQLITE_DBCONFIG_DQS_DDL</dt>
+** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
+** the legacy [double-quoted string literal] misfeature for DDL statements,
+** such as CREATE TABLE and CREATE INDEX. The
+** default value of this setting is determined by the [-DSQLITE_DQS]
+** compile-time option.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
+** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</dt>
+** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
+** assume that database schemas are untainted by malicious content.
+** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
+** takes additional defensive steps to protect the application from harm
+** including:
+** <ul>
+** <li> Prohibit the use of SQL functions inside triggers, views,
+** CHECK constraints, DEFAULT clauses, expression indexes,
+** partial indexes, or generated columns
+** unless those functions are tagged with [SQLITE_INNOCUOUS].
+** <li> Prohibit the use of virtual tables inside of triggers or views
+** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
+** </ul>
+** This setting defaults to "on" for legacy compatibility, however
+** all applications are advised to turn it off if possible. This setting
+** can also be controlled using the [PRAGMA trusted_schema] statement.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
+** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</dt>
+** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
+** the legacy file format flag.  When activated, this flag causes all newly
+** created database file to have a schema format version number (the 4-byte
+** integer found at offset 44 into the database header) of 1.  This in turn
+** means that the resulting database file will be readable and writable by
+** any SQLite version back to 3.0.0 ([dateof:3.0.0]).  Without this setting,
+** newly created databases are generally not understandable by SQLite versions
+** prior to 3.3.0 ([dateof:3.3.0]).  As these words are written, there
+** is now scarcely any need to generate database files that are compatible
+** all the way back to version 3.0.0, and so this setting is of little
+** practical use, but is provided so that SQLite can continue to claim the
+** ability to generate new database files that are compatible with  version
+** 3.0.0.
+** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
+** the [VACUUM] command will fail with an obscure error when attempting to
+** process a table with generated columns and a descending index.  This is
+** not considered a bug since SQLite versions 3.3.0 and earlier do not support
+** either generated columns or descending indexes.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_STMT_SCANSTATUS]]
+** <dt>SQLITE_DBCONFIG_STMT_SCANSTATUS</dt>
+** <dd>The SQLITE_DBCONFIG_STMT_SCANSTATUS option is only useful in
+** SQLITE_ENABLE_STMT_SCANSTATUS builds. In this case, it sets or clears
+** a flag that enables collection of the sqlite3_stmt_scanstatus_v2()
+** statistics. For statistics to be collected, the flag must be set on
+** the database handle both when the SQL statement is prepared and when it
+** is stepped. The flag is set (collection of statistics is enabled)
+** by default. <p>This option takes two arguments: an integer and a pointer to
+** an integer..  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the statement scanstatus option.  If the second argument
+** is not NULL, then the value of the statement scanstatus setting after
+** processing the first argument is written into the integer that the second
+** argument points to.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_REVERSE_SCANORDER]]
+** <dt>SQLITE_DBCONFIG_REVERSE_SCANORDER</dt>
+** <dd>The SQLITE_DBCONFIG_REVERSE_SCANORDER option changes the default order
+** in which tables and indexes are scanned so that the scans start at the end
+** and work toward the beginning rather than starting at the beginning and
+** working toward the end. Setting SQLITE_DBCONFIG_REVERSE_SCANORDER is the
+** same as setting [PRAGMA reverse_unordered_selects]. <p>This option takes
+** two arguments which are an integer and a pointer to an integer.  The first
+** argument is 1, 0, or -1 to enable, disable, or leave unchanged the
+** reverse scan order flag, respectively.  If the second argument is not NULL,
+** then 0 or 1 is written into the integer that the second argument points to
+** depending on if the reverse scan order flag is set after processing the
+** first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]]
+** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE option enables or disables
+** the ability of the [ATTACH DATABASE] SQL command to create a new database
+** file if the database filed named in the ATTACH command does not already
+** exist.  This ability of ATTACH to create a new database is enabled by
+** default.  Applications can disable or reenable the ability for ATTACH to
+** create new database files using this DBCONFIG option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the attach-create flag, respectively.  If the second
+** argument is not NULL, then 0 or 1 is written into the integer that the
+** second argument points to depending on if the attach-create flag is set
+** after processing the first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE]]
+** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE option enables or disables the
+** ability of the [ATTACH DATABASE] SQL command to open a database for writing.
+** This capability is enabled by default.  Applications can disable or
+** reenable this capability using the current DBCONFIG option.  If the
+** the this capability is disabled, the [ATTACH] command will still work,
+** but the database will be opened read-only.  If this option is disabled,
+** then the ability to create a new database using [ATTACH] is also disabled,
+** regardless of the value of the [SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]
+** option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the ability to ATTACH another database for writing,
+** respectively.  If the second argument is not NULL, then 0 or 1 is written
+** into the integer to which the second argument points, depending on whether
+** the ability to ATTACH a read/write database is enabled or disabled
+** after processing the first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_COMMENTS]]
+** <dt>SQLITE_DBCONFIG_ENABLE_COMMENTS</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_COMMENTS option enables or disables the
+** ability to include comments in SQL text.  Comments are enabled by default.
+** An application can disable or reenable comments in SQL text using this
+** DBCONFIG option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the ability to use comments in SQL text,
+** respectively.  If the second argument is not NULL, then 0 or 1 is written
+** into the integer that the second argument points to depending on if
+** comments are allowed in SQL text after processing the first argument.
+** </dd>
+**
+** </dl>
+**
+** [[DBCONFIG arguments]] <h3>Arguments To SQLITE_DBCONFIG Options</h3>
+**
+** <p>Most of the SQLITE_DBCONFIG options take two arguments, so that the
+** overall call to [sqlite3_db_config()] has a total of four parameters.
+** The first argument (the third parameter to sqlite3_db_config()) is a integer.
+** The second argument is a pointer to an integer.  If the first argument is 1,
+** then the option becomes enabled.  If the first integer argument is 0, then the
+** option is disabled.  If the first argument is -1, then the option setting
+** is unchanged.  The second argument, the pointer to an integer, may be NULL.
+** If the second argument is not NULL, then a value of 0 or 1 is written into
+** the integer to which the second argument points, depending on whether the
+** setting is disabled or enabled after applying any changes specified by
+** the first argument.
+**
+** <p>While most SQLITE_DBCONFIG options use the argument format
+** described in the previous paragraph, the [SQLITE_DBCONFIG_MAINDBNAME]
+** and [SQLITE_DBCONFIG_LOOKASIDE] options are different.  See the
+** documentation of those exceptional options for details.
+*/
+#define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
+#define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
+#define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
+#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
+#define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
+#define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
+#define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
+#define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
+#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
+#define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
+#define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
+#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
+#define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
+#define SQLITE_DBCONFIG_STMT_SCANSTATUS       1018 /* int int* */
+#define SQLITE_DBCONFIG_REVERSE_SCANORDER     1019 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE  1020 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE   1021 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_COMMENTS       1022 /* int int* */
+#define SQLITE_DBCONFIG_MAX                   1022 /* Largest DBCONFIG */
+
+/*
+** CAPI3REF: Enable Or Disable Extended Result Codes
+** METHOD: sqlite3
+**
+** ^The sqlite3_extended_result_codes() routine enables or disables the
+** [extended result codes] feature of SQLite. ^The extended result
+** codes are disabled by default for historical compatibility.
+*/
+SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
+
+/*
+** CAPI3REF: Last Insert Rowid
+** METHOD: sqlite3
+**
+** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
+** has a unique 64-bit signed
+** integer key called the [ROWID | "rowid"]. ^The rowid is always available
+** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
+** names are not also used by explicitly declared columns. ^If
+** the table has a column of type [INTEGER PRIMARY KEY] then that column
+** is another alias for the rowid.
+**
+** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
+** the most recent successful [INSERT] into a rowid table or [virtual table]
+** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
+** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
+** on the database connection D, then sqlite3_last_insert_rowid(D) returns
+** zero.
+**
+** As well as being set automatically as rows are inserted into database
+** tables, the value returned by this function may be set explicitly by
+** [sqlite3_set_last_insert_rowid()]
+**
+** Some virtual table implementations may INSERT rows into rowid tables as
+** part of committing a transaction (e.g. to flush data accumulated in memory
+** to disk). In this case subsequent calls to this function return the rowid
+** associated with these internal INSERT operations, which leads to
+** unintuitive results. Virtual table implementations that do write to rowid
+** tables in this way can avoid this problem by restoring the original
+** rowid value using [sqlite3_set_last_insert_rowid()] before returning
+** control to the user.
+**
+** ^(If an [INSERT] occurs within a trigger then this routine will
+** return the [rowid] of the inserted row as long as the trigger is
+** running. Once the trigger program ends, the value returned
+** by this routine reverts to what it was before the trigger was fired.)^
+**
+** ^An [INSERT] that fails due to a constraint violation is not a
+** successful [INSERT] and does not change the value returned by this
+** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
+** and INSERT OR ABORT make no changes to the return value of this
+** routine when their insertion fails.  ^(When INSERT OR REPLACE
+** encounters a constraint violation, it does not fail.  The
+** INSERT continues to completion after deleting rows that caused
+** the constraint problem so INSERT OR REPLACE will always change
+** the return value of this interface.)^
+**
+** ^For the purposes of this routine, an [INSERT] is considered to
+** be successful even if it is subsequently rolled back.
+**
+** This function is accessible to SQL statements via the
+** [last_insert_rowid() SQL function].
+**
+** If a separate thread performs a new [INSERT] on the same
+** database connection while the [sqlite3_last_insert_rowid()]
+** function is running and thus changes the last insert [rowid],
+** then the value returned by [sqlite3_last_insert_rowid()] is
+** unpredictable and might not equal either the old or the new
+** last insert [rowid].
+*/
+SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
+
+/*
+** CAPI3REF: Set the Last Insert Rowid value.
+** METHOD: sqlite3
+**
+** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
+** set the value returned by calling sqlite3_last_insert_rowid(D) to R
+** without inserting a row into the database.
+*/
+SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
+
+/*
+** CAPI3REF: Count The Number Of Rows Modified
+** METHOD: sqlite3
+**
+** ^These functions return the number of rows modified, inserted or
+** deleted by the most recently completed INSERT, UPDATE or DELETE
+** statement on the database connection specified by the only parameter.
+** The two functions are identical except for the type of the return value
+** and that if the number of rows modified by the most recent INSERT, UPDATE,
+** or DELETE is greater than the maximum value supported by type "int", then
+** the return value of sqlite3_changes() is undefined. ^Executing any other
+** type of SQL statement does not modify the value returned by these functions.
+** For the purposes of this interface, a CREATE TABLE AS SELECT statement
+** does not count as an INSERT, UPDATE or DELETE statement and hence the rows
+** added to the new table by the CREATE TABLE AS SELECT statement are not
+** counted.
+**
+** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
+** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
+** [foreign key actions] or [REPLACE] constraint resolution are not counted.
+**
+** Changes to a view that are intercepted by
+** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
+** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
+** DELETE statement run on a view is always zero. Only changes made to real
+** tables are counted.
+**
+** Things are more complicated if the sqlite3_changes() function is
+** executed while a trigger program is running. This may happen if the
+** program uses the [changes() SQL function], or if some other callback
+** function invokes sqlite3_changes() directly. Essentially:
+**
+** <ul>
+**   <li> ^(Before entering a trigger program the value returned by
+**        sqlite3_changes() function is saved. After the trigger program
+**        has finished, the original value is restored.)^
+**
+**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
+**        statement sets the value returned by sqlite3_changes()
+**        upon completion as normal. Of course, this value will not include
+**        any changes performed by sub-triggers, as the sqlite3_changes()
+**        value will be saved and restored after each sub-trigger has run.)^
+** </ul>
+**
+** ^This means that if the changes() SQL function (or similar) is used
+** by the first INSERT, UPDATE or DELETE statement within a trigger, it
+** returns the value as set when the calling statement began executing.
+** ^If it is used by the second or subsequent such statement within a trigger
+** program, the value returned reflects the number of rows modified by the
+** previous INSERT, UPDATE or DELETE statement within the same trigger.
+**
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_changes()] is running then the value returned
+** is unpredictable and not meaningful.
+**
+** See also:
+** <ul>
+** <li> the [sqlite3_total_changes()] interface
+** <li> the [count_changes pragma]
+** <li> the [changes() SQL function]
+** <li> the [data_version pragma]
+** </ul>
+*/
+SQLITE_API int sqlite3_changes(sqlite3*);
+SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3*);
+
+/*
+** CAPI3REF: Total Number Of Rows Modified
+** METHOD: sqlite3
+**
+** ^These functions return the total number of rows inserted, modified or
+** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
+** since the database connection was opened, including those executed as
+** part of trigger programs. The two functions are identical except for the
+** type of the return value and that if the number of rows modified by the
+** connection exceeds the maximum value supported by type "int", then
+** the return value of sqlite3_total_changes() is undefined. ^Executing
+** any other type of SQL statement does not affect the value returned by
+** sqlite3_total_changes().
+**
+** ^Changes made as part of [foreign key actions] are included in the
+** count, but those made as part of REPLACE constraint resolution are
+** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
+** are not counted.
+**
+** The [sqlite3_total_changes(D)] interface only reports the number
+** of rows that changed due to SQL statement run against database
+** connection D.  Any changes by other database connections are ignored.
+** To detect changes against a database file from other database
+** connections use the [PRAGMA data_version] command or the
+** [SQLITE_FCNTL_DATA_VERSION] [file control].
+**
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_total_changes()] is running then the value
+** returned is unpredictable and not meaningful.
+**
+** See also:
+** <ul>
+** <li> the [sqlite3_changes()] interface
+** <li> the [count_changes pragma]
+** <li> the [changes() SQL function]
+** <li> the [data_version pragma]
+** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
+** </ul>
+*/
+SQLITE_API int sqlite3_total_changes(sqlite3*);
+SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3*);
+
+/*
+** CAPI3REF: Interrupt A Long-Running Query
+** METHOD: sqlite3
+**
+** ^This function causes any pending database operation to abort and
+** return at its earliest opportunity. This routine is typically
+** called in response to a user action such as pressing "Cancel"
+** or Ctrl-C where the user wants a long query operation to halt
+** immediately.
+**
+** ^It is safe to call this routine from a thread different from the
+** thread that is currently running the database operation.  But it
+** is not safe to call this routine with a [database connection] that
+** is closed or might close before sqlite3_interrupt() returns.
+**
+** ^If an SQL operation is very nearly finished at the time when
+** sqlite3_interrupt() is called, then it might not have an opportunity
+** to be interrupted and might continue to completion.
+**
+** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
+** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
+** that is inside an explicit transaction, then the entire transaction
+** will be rolled back automatically.
+**
+** ^The sqlite3_interrupt(D) call is in effect until all currently running
+** SQL statements on [database connection] D complete.  ^Any new SQL statements
+** that are started after the sqlite3_interrupt() call and before the
+** running statement count reaches zero are interrupted as if they had been
+** running prior to the sqlite3_interrupt() call.  ^New SQL statements
+** that are started after the running statement count reaches zero are
+** not effected by the sqlite3_interrupt().
+** ^A call to sqlite3_interrupt(D) that occurs when there are no running
+** SQL statements is a no-op and has no effect on SQL statements
+** that are started after the sqlite3_interrupt() call returns.
+**
+** ^The [sqlite3_is_interrupted(D)] interface can be used to determine whether
+** or not an interrupt is currently in effect for [database connection] D.
+** It returns 1 if an interrupt is currently in effect, or 0 otherwise.
+*/
+SQLITE_API void sqlite3_interrupt(sqlite3*);
+SQLITE_API int sqlite3_is_interrupted(sqlite3*);
+
+/*
+** CAPI3REF: Determine If An SQL Statement Is Complete
+**
+** These routines are useful during command-line input to determine if the
+** currently entered text seems to form a complete SQL statement or
+** if additional input is needed before sending the text into
+** SQLite for parsing.  ^These routines return 1 if the input string
+** appears to be a complete SQL statement.  ^A statement is judged to be
+** complete if it ends with a semicolon token and is not a prefix of a
+** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
+** string literals or quoted identifier names or comments are not
+** independent tokens (they are part of the token in which they are
+** embedded) and thus do not count as a statement terminator.  ^Whitespace
+** and comments that follow the final semicolon are ignored.
+**
+** ^These routines return 0 if the statement is incomplete.  ^If a
+** memory allocation fails, then SQLITE_NOMEM is returned.
+**
+** ^These routines do not parse the SQL statements thus
+** will not detect syntactically incorrect SQL.
+**
+** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
+** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
+** automatically by sqlite3_complete16().  If that initialization fails,
+** then the return value from sqlite3_complete16() will be non-zero
+** regardless of whether or not the input SQL is complete.)^
+**
+** The input to [sqlite3_complete()] must be a zero-terminated
+** UTF-8 string.
+**
+** The input to [sqlite3_complete16()] must be a zero-terminated
+** UTF-16 string in native byte order.
+*/
+SQLITE_API int sqlite3_complete(const char *sql);
+SQLITE_API int sqlite3_complete16(const void *sql);
+
+/*
+** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
+** KEYWORDS: {busy-handler callback} {busy handler}
+** METHOD: sqlite3
+**
+** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
+** that might be invoked with argument P whenever
+** an attempt is made to access a database table associated with
+** [database connection] D when another thread
+** or process has the table locked.
+** The sqlite3_busy_handler() interface is used to implement
+** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
+**
+** ^If the busy callback is NULL, then [SQLITE_BUSY]
+** is returned immediately upon encountering the lock.  ^If the busy callback
+** is not NULL, then the callback might be invoked with two arguments.
+**
+** ^The first argument to the busy handler is a copy of the void* pointer which
+** is the third argument to sqlite3_busy_handler().  ^The second argument to
+** the busy handler callback is the number of times that the busy handler has
+** been invoked previously for the same locking event.  ^If the
+** busy callback returns 0, then no additional attempts are made to
+** access the database and [SQLITE_BUSY] is returned
+** to the application.
+** ^If the callback returns non-zero, then another attempt
+** is made to access the database and the cycle repeats.
+**
+** The presence of a busy handler does not guarantee that it will be invoked
+** when there is lock contention. ^If SQLite determines that invoking the busy
+** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
+** to the application instead of invoking the
+** busy handler.
+** Consider a scenario where one process is holding a read lock that
+** it is trying to promote to a reserved lock and
+** a second process is holding a reserved lock that it is trying
+** to promote to an exclusive lock.  The first process cannot proceed
+** because it is blocked by the second and the second process cannot
+** proceed because it is blocked by the first.  If both processes
+** invoke the busy handlers, neither will make any progress.  Therefore,
+** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
+** will induce the first process to release its read lock and allow
+** the second process to proceed.
+**
+** ^The default busy callback is NULL.
+**
+** ^(There can only be a single busy handler defined for each
+** [database connection].  Setting a new busy handler clears any
+** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
+** or evaluating [PRAGMA busy_timeout=N] will change the
+** busy handler and thus clear any previously set busy handler.
+**
+** The busy callback should not take any actions which modify the
+** database connection that invoked the busy handler.  In other words,
+** the busy handler is not reentrant.  Any such actions
+** result in undefined behavior.
+**
+** A busy handler must not close the database connection
+** or [prepared statement] that invoked the busy handler.
+*/
+SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
+
+/*
+** CAPI3REF: Set A Busy Timeout
+** METHOD: sqlite3
+**
+** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
+** for a specified amount of time when a table is locked.  ^The handler
+** will sleep multiple times until at least "ms" milliseconds of sleeping
+** have accumulated.  ^After at least "ms" milliseconds of sleeping,
+** the handler returns 0 which causes [sqlite3_step()] to return
+** [SQLITE_BUSY].
+**
+** ^Calling this routine with an argument less than or equal to zero
+** turns off all busy handlers.
+**
+** ^(There can only be a single busy handler for a particular
+** [database connection] at any given moment.  If another busy handler
+** was defined  (using [sqlite3_busy_handler()]) prior to calling
+** this routine, that other busy handler is cleared.)^
+**
+** See also:  [PRAGMA busy_timeout]
+*/
+SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
+
+/*
+** CAPI3REF: Convenience Routines For Running Queries
+** METHOD: sqlite3
+**
+** This is a legacy interface that is preserved for backwards compatibility.
+** Use of this interface is not recommended.
+**
+** Definition: A <b>result table</b> is memory data structure created by the
+** [sqlite3_get_table()] interface.  A result table records the
+** complete query results from one or more queries.
+**
+** The table conceptually has a number of rows and columns.  But
+** these numbers are not part of the result table itself.  These
+** numbers are obtained separately.  Let N be the number of rows
+** and M be the number of columns.
+**
+** A result table is an array of pointers to zero-terminated UTF-8 strings.
+** There are (N+1)*M elements in the array.  The first M pointers point
+** to zero-terminated strings that  contain the names of the columns.
+** The remaining entries all point to query results.  NULL values result
+** in NULL pointers.  All other values are in their UTF-8 zero-terminated
+** string representation as returned by [sqlite3_column_text()].
+**
+** A result table might consist of one or more memory allocations.
+** It is not safe to pass a result table directly to [sqlite3_free()].
+** A result table should be deallocated using [sqlite3_free_table()].
+**
+** ^(As an example of the result table format, suppose a query result
+** is as follows:
+**
+** <blockquote><pre>
+**        Name        | Age
+**        -----------------------
+**        Alice       | 43
+**        Bob         | 28
+**        Cindy       | 21
+** </pre></blockquote>
+**
+** There are two columns (M==2) and three rows (N==3).  Thus the
+** result table has 8 entries.  Suppose the result table is stored
+** in an array named azResult.  Then azResult holds this content:
+**
+** <blockquote><pre>
+**        azResult[0] = "Name";
+**        azResult[1] = "Age";
+**        azResult[2] = "Alice";
+**        azResult[3] = "43";
+**        azResult[4] = "Bob";
+**        azResult[5] = "28";
+**        azResult[6] = "Cindy";
+**        azResult[7] = "21";
+** </pre></blockquote>)^
+**
+** ^The sqlite3_get_table() function evaluates one or more
+** semicolon-separated SQL statements in the zero-terminated UTF-8
+** string of its 2nd parameter and returns a result table to the
+** pointer given in its 3rd parameter.
+**
+** After the application has finished with the result from sqlite3_get_table(),
+** it must pass the result table pointer to sqlite3_free_table() in order to
+** release the memory that was malloced.  Because of the way the
+** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
+** function must not try to call [sqlite3_free()] directly.  Only
+** [sqlite3_free_table()] is able to release the memory properly and safely.
+**
+** The sqlite3_get_table() interface is implemented as a wrapper around
+** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
+** to any internal data structures of SQLite.  It uses only the public
+** interface defined here.  As a consequence, errors that occur in the
+** wrapper layer outside of the internal [sqlite3_exec()] call are not
+** reflected in subsequent calls to [sqlite3_errcode()] or
+** [sqlite3_errmsg()].
+*/
+SQLITE_API int sqlite3_get_table(
+  sqlite3 *db,          /* An open database */
+  const char *zSql,     /* SQL to be evaluated */
+  char ***pazResult,    /* Results of the query */
+  int *pnRow,           /* Number of result rows written here */
+  int *pnColumn,        /* Number of result columns written here */
+  char **pzErrmsg       /* Error msg written here */
+);
+SQLITE_API void sqlite3_free_table(char **result);
+
+/*
+** CAPI3REF: Formatted String Printing Functions
+**
+** These routines are work-alikes of the "printf()" family of functions
+** from the standard C library.
+** These routines understand most of the common formatting options from
+** the standard library printf()
+** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
+** See the [built-in printf()] documentation for details.
+**
+** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
+** results into memory obtained from [sqlite3_malloc64()].
+** The strings returned by these two routines should be
+** released by [sqlite3_free()].  ^Both routines return a
+** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
+** memory to hold the resulting string.
+**
+** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
+** the standard C library.  The result is written into the
+** buffer supplied as the second parameter whose size is given by
+** the first parameter. Note that the order of the
+** first two parameters is reversed from snprintf().)^  This is an
+** historical accident that cannot be fixed without breaking
+** backwards compatibility.  ^(Note also that sqlite3_snprintf()
+** returns a pointer to its buffer instead of the number of
+** characters actually written into the buffer.)^  We admit that
+** the number of characters written would be a more useful return
+** value but we cannot change the implementation of sqlite3_snprintf()
+** now without breaking compatibility.
+**
+** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
+** guarantees that the buffer is always zero-terminated.  ^The first
+** parameter "n" is the total size of the buffer, including space for
+** the zero terminator.  So the longest string that can be completely
+** written will be n-1 characters.
+**
+** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
+**
+** See also:  [built-in printf()], [printf() SQL function]
+*/
+SQLITE_API char *sqlite3_mprintf(const char*,...);
+SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
+SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
+SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
+
+/*
+** CAPI3REF: Memory Allocation Subsystem
+**
+** The SQLite core uses these three routines for all of its own
+** internal memory allocation needs. "Core" in the previous sentence
+** does not include operating-system specific [VFS] implementation.  The
+** Windows VFS uses native malloc() and free() for some operations.
+**
+** ^The sqlite3_malloc() routine returns a pointer to a block
+** of memory at least N bytes in length, where N is the parameter.
+** ^If sqlite3_malloc() is unable to obtain sufficient free
+** memory, it returns a NULL pointer.  ^If the parameter N to
+** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
+** a NULL pointer.
+**
+** ^The sqlite3_malloc64(N) routine works just like
+** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
+** of a signed 32-bit integer.
+**
+** ^Calling sqlite3_free() with a pointer previously returned
+** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
+** that it might be reused.  ^The sqlite3_free() routine is
+** a no-op if is called with a NULL pointer.  Passing a NULL pointer
+** to sqlite3_free() is harmless.  After being freed, memory
+** should neither be read nor written.  Even reading previously freed
+** memory might result in a segmentation fault or other severe error.
+** Memory corruption, a segmentation fault, or other severe error
+** might result if sqlite3_free() is called with a non-NULL pointer that
+** was not obtained from sqlite3_malloc() or sqlite3_realloc().
+**
+** ^The sqlite3_realloc(X,N) interface attempts to resize a
+** prior memory allocation X to be at least N bytes.
+** ^If the X parameter to sqlite3_realloc(X,N)
+** is a NULL pointer then its behavior is identical to calling
+** sqlite3_malloc(N).
+** ^If the N parameter to sqlite3_realloc(X,N) is zero or
+** negative then the behavior is exactly the same as calling
+** sqlite3_free(X).
+** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
+** of at least N bytes in size or NULL if insufficient memory is available.
+** ^If M is the size of the prior allocation, then min(N,M) bytes
+** of the prior allocation are copied into the beginning of buffer returned
+** by sqlite3_realloc(X,N) and the prior allocation is freed.
+** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
+** prior allocation is not freed.
+**
+** ^The sqlite3_realloc64(X,N) interfaces works the same as
+** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
+** of a 32-bit signed integer.
+**
+** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
+** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
+** sqlite3_msize(X) returns the size of that memory allocation in bytes.
+** ^The value returned by sqlite3_msize(X) might be larger than the number
+** of bytes requested when X was allocated.  ^If X is a NULL pointer then
+** sqlite3_msize(X) returns zero.  If X points to something that is not
+** the beginning of memory allocation, or if it points to a formerly
+** valid memory allocation that has now been freed, then the behavior
+** of sqlite3_msize(X) is undefined and possibly harmful.
+**
+** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
+** sqlite3_malloc64(), and sqlite3_realloc64()
+** is always aligned to at least an 8 byte boundary, or to a
+** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
+** option is used.
+**
+** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
+** must be either NULL or else pointers obtained from a prior
+** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
+** not yet been released.
+**
+** The application must not read or write any part of
+** a block of memory after it has been released using
+** [sqlite3_free()] or [sqlite3_realloc()].
+*/
+SQLITE_API void *sqlite3_malloc(int);
+SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
+SQLITE_API void *sqlite3_realloc(void*, int);
+SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
+SQLITE_API void sqlite3_free(void*);
+SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
+
+/*
+** CAPI3REF: Memory Allocator Statistics
+**
+** SQLite provides these two interfaces for reporting on the status
+** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
+** routines, which form the built-in memory allocation subsystem.
+**
+** ^The [sqlite3_memory_used()] routine returns the number of bytes
+** of memory currently outstanding (malloced but not freed).
+** ^The [sqlite3_memory_highwater()] routine returns the maximum
+** value of [sqlite3_memory_used()] since the high-water mark
+** was last reset.  ^The values returned by [sqlite3_memory_used()] and
+** [sqlite3_memory_highwater()] include any overhead
+** added by SQLite in its implementation of [sqlite3_malloc()],
+** but not overhead added by the any underlying system library
+** routines that [sqlite3_malloc()] may call.
+**
+** ^The memory high-water mark is reset to the current value of
+** [sqlite3_memory_used()] if and only if the parameter to
+** [sqlite3_memory_highwater()] is true.  ^The value returned
+** by [sqlite3_memory_highwater(1)] is the high-water mark
+** prior to the reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
+
+/*
+** CAPI3REF: Pseudo-Random Number Generator
+**
+** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
+** select random [ROWID | ROWIDs] when inserting new records into a table that
+** already uses the largest possible [ROWID].  The PRNG is also used for
+** the built-in random() and randomblob() SQL functions.  This interface allows
+** applications to access the same PRNG for other purposes.
+**
+** ^A call to this routine stores N bytes of randomness into buffer P.
+** ^The P parameter can be a NULL pointer.
+**
+** ^If this routine has not been previously called or if the previous
+** call had N less than one or a NULL pointer for P, then the PRNG is
+** seeded using randomness obtained from the xRandomness method of
+** the default [sqlite3_vfs] object.
+** ^If the previous call to this routine had an N of 1 or more and a
+** non-NULL P then the pseudo-randomness is generated
+** internally and without recourse to the [sqlite3_vfs] xRandomness
+** method.
+*/
+SQLITE_API void sqlite3_randomness(int N, void *P);
+
+/*
+** CAPI3REF: Compile-Time Authorization Callbacks
+** METHOD: sqlite3
+** KEYWORDS: {authorizer callback}
+**
+** ^This routine registers an authorizer callback with a particular
+** [database connection], supplied in the first argument.
+** ^The authorizer callback is invoked as SQL statements are being compiled
+** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
+** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
+** and [sqlite3_prepare16_v3()].  ^At various
+** points during the compilation process, as logic is being created
+** to perform various actions, the authorizer callback is invoked to
+** see if those actions are allowed.  ^The authorizer callback should
+** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
+** specific action but allow the SQL statement to continue to be
+** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
+** rejected with an error.  ^If the authorizer callback returns
+** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
+** then the [sqlite3_prepare_v2()] or equivalent call that triggered
+** the authorizer will fail with an error message.
+**
+** When the callback returns [SQLITE_OK], that means the operation
+** requested is ok.  ^When the callback returns [SQLITE_DENY], the
+** [sqlite3_prepare_v2()] or equivalent call that triggered the
+** authorizer will fail with an error message explaining that
+** access is denied.
+**
+** ^The first parameter to the authorizer callback is a copy of the third
+** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
+** to the callback is an integer [SQLITE_COPY | action code] that specifies
+** the particular action to be authorized. ^The third through sixth parameters
+** to the callback are either NULL pointers or zero-terminated strings
+** that contain additional details about the action to be authorized.
+** Applications must always be prepared to encounter a NULL pointer in any
+** of the third through the sixth parameters of the authorization callback.
+**
+** ^If the action code is [SQLITE_READ]
+** and the callback returns [SQLITE_IGNORE] then the
+** [prepared statement] statement is constructed to substitute
+** a NULL value in place of the table column that would have
+** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
+** return can be used to deny an untrusted user access to individual
+** columns of a table.
+** ^When a table is referenced by a [SELECT] but no column values are
+** extracted from that table (for example in a query like
+** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
+** is invoked once for that table with a column name that is an empty string.
+** ^If the action code is [SQLITE_DELETE] and the callback returns
+** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
+** [truncate optimization] is disabled and all rows are deleted individually.
+**
+** An authorizer is used when [sqlite3_prepare | preparing]
+** SQL statements from an untrusted source, to ensure that the SQL statements
+** do not try to access data they are not allowed to see, or that they do not
+** try to execute malicious statements that damage the database.  For
+** example, an application may allow a user to enter arbitrary
+** SQL queries for evaluation by a database.  But the application does
+** not want the user to be able to make arbitrary changes to the
+** database.  An authorizer could then be put in place while the
+** user-entered SQL is being [sqlite3_prepare | prepared] that
+** disallows everything except [SELECT] statements.
+**
+** Applications that need to process SQL from untrusted sources
+** might also consider lowering resource limits using [sqlite3_limit()]
+** and limiting database size using the [max_page_count] [PRAGMA]
+** in addition to using an authorizer.
+**
+** ^(Only a single authorizer can be in place on a database connection
+** at a time.  Each call to sqlite3_set_authorizer overrides the
+** previous call.)^  ^Disable the authorizer by installing a NULL callback.
+** The authorizer is disabled by default.
+**
+** The authorizer callback must not do anything that will modify
+** the database connection that invoked the authorizer callback.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
+** statement might be re-prepared during [sqlite3_step()] due to a
+** schema change.  Hence, the application should ensure that the
+** correct authorizer callback remains in place during the [sqlite3_step()].
+**
+** ^Note that the authorizer callback is invoked only during
+** [sqlite3_prepare()] or its variants.  Authorization is not
+** performed during statement evaluation in [sqlite3_step()], unless
+** as stated in the previous paragraph, sqlite3_step() invokes
+** sqlite3_prepare_v2() to reprepare a statement after a schema change.
+*/
+SQLITE_API int sqlite3_set_authorizer(
+  sqlite3*,
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
+  void *pUserData
+);
+
+/*
+** CAPI3REF: Authorizer Return Codes
+**
+** The [sqlite3_set_authorizer | authorizer callback function] must
+** return either [SQLITE_OK] or one of these two constants in order
+** to signal SQLite whether or not the action is permitted.  See the
+** [sqlite3_set_authorizer | authorizer documentation] for additional
+** information.
+**
+** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
+** returned from the [sqlite3_vtab_on_conflict()] interface.
+*/
+#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
+#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
+
+/*
+** CAPI3REF: Authorizer Action Codes
+**
+** The [sqlite3_set_authorizer()] interface registers a callback function
+** that is invoked to authorize certain SQL statement actions.  The
+** second parameter to the callback is an integer code that specifies
+** what action is being authorized.  These are the integer action codes that
+** the authorizer callback may be passed.
+**
+** These action code values signify what kind of operation is to be
+** authorized.  The 3rd and 4th parameters to the authorization
+** callback function will be parameters or NULL depending on which of these
+** codes is used as the second parameter.  ^(The 5th parameter to the
+** authorizer callback is the name of the database ("main", "temp",
+** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
+** is the name of the inner-most trigger or view that is responsible for
+** the access attempt or NULL if this access attempt is directly from
+** top-level SQL code.
+*/
+/******************************************* 3rd ************ 4th ***********/
+#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
+#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
+#define SQLITE_DELETE                9   /* Table Name      NULL            */
+#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
+#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
+#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
+#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
+#define SQLITE_INSERT               18   /* Table Name      NULL            */
+#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
+#define SQLITE_READ                 20   /* Table Name      Column Name     */
+#define SQLITE_SELECT               21   /* NULL            NULL            */
+#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
+#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
+#define SQLITE_ATTACH               24   /* Filename        NULL            */
+#define SQLITE_DETACH               25   /* Database Name   NULL            */
+#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
+#define SQLITE_REINDEX              27   /* Index Name      NULL            */
+#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
+#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
+#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
+#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
+#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
+#define SQLITE_COPY                  0   /* No longer used */
+#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
+
+/*
+** CAPI3REF: Deprecated Tracing And Profiling Functions
+** DEPRECATED
+**
+** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
+** instead of the routines described here.
+**
+** These routines register callback functions that can be used for
+** tracing and profiling the execution of SQL statements.
+**
+** ^The callback function registered by sqlite3_trace() is invoked at
+** various times when an SQL statement is being run by [sqlite3_step()].
+** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
+** SQL statement text as the statement first begins executing.
+** ^(Additional sqlite3_trace() callbacks might occur
+** as each triggered subprogram is entered.  The callbacks for triggers
+** contain a UTF-8 SQL comment that identifies the trigger.)^
+**
+** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
+** the length of [bound parameter] expansion in the output of sqlite3_trace().
+**
+** ^The callback function registered by sqlite3_profile() is invoked
+** as each SQL statement finishes.  ^The profile callback contains
+** the original statement text and an estimate of wall-clock time
+** of how long that statement took to run.  ^The profile callback
+** time is in units of nanoseconds, however the current implementation
+** is only capable of millisecond resolution so the six least significant
+** digits in the time are meaningless.  Future versions of SQLite
+** might provide greater resolution on the profiler callback.  Invoking
+** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
+** profile callback.
+*/
+SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
+   void(*xTrace)(void*,const char*), void*);
+SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
+   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
+
+/*
+** CAPI3REF: SQL Trace Event Codes
+** KEYWORDS: SQLITE_TRACE
+**
+** These constants identify classes of events that can be monitored
+** using the [sqlite3_trace_v2()] tracing logic.  The M argument
+** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
+** the following constants.  ^The first argument to the trace callback
+** is one of the following constants.
+**
+** New tracing constants may be added in future releases.
+**
+** ^A trace callback has four arguments: xCallback(T,C,P,X).
+** ^The T argument is one of the integer type codes above.
+** ^The C argument is a copy of the context pointer passed in as the
+** fourth argument to [sqlite3_trace_v2()].
+** The P and X arguments are pointers whose meanings depend on T.
+**
+** <dl>
+** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
+** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
+** first begins running and possibly at other times during the
+** execution of the prepared statement, such as at the start of each
+** trigger subprogram. ^The P argument is a pointer to the
+** [prepared statement]. ^The X argument is a pointer to a string which
+** is the unexpanded SQL text of the prepared statement or an SQL comment
+** that indicates the invocation of a trigger.  ^The callback can compute
+** the same text that would have been returned by the legacy [sqlite3_trace()]
+** interface by using the X argument when X begins with "--" and invoking
+** [sqlite3_expanded_sql(P)] otherwise.
+**
+** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
+** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
+** information as is provided by the [sqlite3_profile()] callback.
+** ^The P argument is a pointer to the [prepared statement] and the
+** X argument points to a 64-bit integer which is approximately
+** the number of nanoseconds that the prepared statement took to run.
+** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
+**
+** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
+** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
+** statement generates a single row of result.
+** ^The P argument is a pointer to the [prepared statement] and the
+** X argument is unused.
+**
+** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
+** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
+** connection closes.
+** ^The P argument is a pointer to the [database connection] object
+** and the X argument is unused.
+** </dl>
+*/
+#define SQLITE_TRACE_STMT       0x01
+#define SQLITE_TRACE_PROFILE    0x02
+#define SQLITE_TRACE_ROW        0x04
+#define SQLITE_TRACE_CLOSE      0x08
+
+/*
+** CAPI3REF: SQL Trace Hook
+** METHOD: sqlite3
+**
+** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
+** function X against [database connection] D, using property mask M
+** and context pointer P.  ^If the X callback is
+** NULL or if the M mask is zero, then tracing is disabled.  The
+** M argument should be the bitwise OR-ed combination of
+** zero or more [SQLITE_TRACE] constants.
+**
+** ^Each call to either sqlite3_trace(D,X,P) or sqlite3_trace_v2(D,M,X,P)
+** overrides (cancels) all prior calls to sqlite3_trace(D,X,P) or
+** sqlite3_trace_v2(D,M,X,P) for the [database connection] D.  Each
+** database connection may have at most one trace callback.
+**
+** ^The X callback is invoked whenever any of the events identified by
+** mask M occur.  ^The integer return value from the callback is currently
+** ignored, though this may change in future releases.  Callback
+** implementations should return zero to ensure future compatibility.
+**
+** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
+** ^The T argument is one of the [SQLITE_TRACE]
+** constants to indicate why the callback was invoked.
+** ^The C argument is a copy of the context pointer.
+** The P and X arguments are pointers whose meanings depend on T.
+**
+** The sqlite3_trace_v2() interface is intended to replace the legacy
+** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
+** are deprecated.
+*/
+SQLITE_API int sqlite3_trace_v2(
+  sqlite3*,
+  unsigned uMask,
+  int(*xCallback)(unsigned,void*,void*,void*),
+  void *pCtx
+);
+
+/*
+** CAPI3REF: Query Progress Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
+** function X to be invoked periodically during long running calls to
+** [sqlite3_step()] and [sqlite3_prepare()] and similar for
+** database connection D.  An example use for this
+** interface is to keep a GUI updated during a large query.
+**
+** ^The parameter P is passed through as the only parameter to the
+** callback function X.  ^The parameter N is the approximate number of
+** [virtual machine instructions] that are evaluated between successive
+** invocations of the callback X.  ^If N is less than one then the progress
+** handler is disabled.
+**
+** ^Only a single progress handler may be defined at one time per
+** [database connection]; setting a new progress handler cancels the
+** old one.  ^Setting parameter X to NULL disables the progress handler.
+** ^The progress handler is also disabled by setting N to a value less
+** than 1.
+**
+** ^If the progress callback returns non-zero, the operation is
+** interrupted.  This feature can be used to implement a
+** "Cancel" button on a GUI progress dialog box.
+**
+** The progress handler callback must not do anything that will modify
+** the database connection that invoked the progress handler.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** The progress handler callback would originally only be invoked from the
+** bytecode engine.  It still might be invoked during [sqlite3_prepare()]
+** and similar because those routines might force a reparse of the schema
+** which involves running the bytecode engine.  However, beginning with
+** SQLite version 3.41.0, the progress handler callback might also be
+** invoked directly from [sqlite3_prepare()] while analyzing and generating
+** code for complex queries.
+*/
+SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
+
+/*
+** CAPI3REF: Opening A New Database Connection
+** CONSTRUCTOR: sqlite3
+**
+** ^These routines open an SQLite database file as specified by the
+** filename argument. ^The filename argument is interpreted as UTF-8 for
+** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
+** order for sqlite3_open16(). ^(A [database connection] handle is usually
+** returned in *ppDb, even if an error occurs.  The only exception is that
+** if SQLite is unable to allocate memory to hold the [sqlite3] object,
+** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
+** object.)^ ^(If the database is opened (and/or created) successfully, then
+** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
+** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
+** an English language description of the error following a failure of any
+** of the sqlite3_open() routines.
+**
+** ^The default encoding will be UTF-8 for databases created using
+** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
+** created using sqlite3_open16() will be UTF-16 in the native byte order.
+**
+** Whether or not an error occurs when it is opened, resources
+** associated with the [database connection] handle should be released by
+** passing it to [sqlite3_close()] when it is no longer required.
+**
+** The sqlite3_open_v2() interface works like sqlite3_open()
+** except that it accepts two additional parameters for additional control
+** over the new database connection.  ^(The flags parameter to
+** sqlite3_open_v2() must include, at a minimum, one of the following
+** three flag combinations:)^
+**
+** <dl>
+** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
+** <dd>The database is opened in read-only mode.  If the database does
+** not already exist, an error is returned.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
+** <dd>The database is opened for reading and writing if possible, or
+** reading only if the file is write protected by the operating
+** system.  In either case the database must already exist, otherwise
+** an error is returned.  For historical reasons, if opening in
+** read-write mode fails due to OS-level permissions, an attempt is
+** made to open it in read-only mode. [sqlite3_db_readonly()] can be
+** used to determine whether the database is actually
+** read-write.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
+** <dd>The database is opened for reading and writing, and is created if
+** it does not already exist. This is the behavior that is always used for
+** sqlite3_open() and sqlite3_open16().</dd>)^
+** </dl>
+**
+** In addition to the required flags, the following optional flags are
+** also supported:
+**
+** <dl>
+** ^(<dt>[SQLITE_OPEN_URI]</dt>
+** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
+** <dd>The database will be opened as an in-memory database.  The database
+** is named by the "filename" argument for the purposes of cache-sharing,
+** if shared cache mode is enabled, but the "filename" is otherwise ignored.
+** </dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
+** <dd>The new database connection will use the "multi-thread"
+** [threading mode].)^  This means that separate threads are allowed
+** to use SQLite at the same time, as long as each thread is using
+** a different [database connection].
+**
+** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
+** <dd>The new database connection will use the "serialized"
+** [threading mode].)^  This means the multiple threads can safely
+** attempt to use the same database connection at the same time.
+** (Mutexes will block any actual concurrency, but in this mode
+** there is no harm in trying.)
+**
+** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
+** <dd>The database is opened [shared cache] enabled, overriding
+** the default shared cache setting provided by
+** [sqlite3_enable_shared_cache()].)^
+** The [use of shared cache mode is discouraged] and hence shared cache
+** capabilities may be omitted from many builds of SQLite.  In such cases,
+** this option is a no-op.
+**
+** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
+** <dd>The database is opened [shared cache] disabled, overriding
+** the default shared cache setting provided by
+** [sqlite3_enable_shared_cache()].)^
+**
+** [[OPEN_EXRESCODE]] ^(<dt>[SQLITE_OPEN_EXRESCODE]</dt>
+** <dd>The database connection comes up in "extended result code mode".
+** In other words, the database behaves as if
+** [sqlite3_extended_result_codes(db,1)] were called on the database
+** connection as soon as the connection is created. In addition to setting
+** the extended result code mode, this flag also causes [sqlite3_open_v2()]
+** to return an extended result code.</dd>
+**
+** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
+** <dd>The database filename is not allowed to contain a symbolic link</dd>
+** </dl>)^
+**
+** If the 3rd parameter to sqlite3_open_v2() is not one of the
+** required combinations shown above optionally combined with other
+** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
+** then the behavior is undefined.  Historic versions of SQLite
+** have silently ignored surplus bits in the flags parameter to
+** sqlite3_open_v2(), however that behavior might not be carried through
+** into future versions of SQLite and so applications should not rely
+** upon it.  Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
+** for sqlite3_open_v2().  The SQLITE_OPEN_EXCLUSIVE does *not* cause
+** the open to fail if the database already exists.  The SQLITE_OPEN_EXCLUSIVE
+** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
+** by sqlite3_open_v2().
+**
+** ^The fourth parameter to sqlite3_open_v2() is the name of the
+** [sqlite3_vfs] object that defines the operating system interface that
+** the new database connection should use.  ^If the fourth parameter is
+** a NULL pointer then the default [sqlite3_vfs] object is used.
+**
+** ^If the filename is ":memory:", then a private, temporary in-memory database
+** is created for the connection.  ^This in-memory database will vanish when
+** the database connection is closed.  Future versions of SQLite might
+** make use of additional special filenames that begin with the ":" character.
+** It is recommended that when a database filename actually does begin with
+** a ":" character you should prefix the filename with a pathname such as
+** "./" to avoid ambiguity.
+**
+** ^If the filename is an empty string, then a private, temporary
+** on-disk database will be created.  ^This private database will be
+** automatically deleted as soon as the database connection is closed.
+**
+** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
+**
+** ^If [URI filename] interpretation is enabled, and the filename argument
+** begins with "file:", then the filename is interpreted as a URI. ^URI
+** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
+** set in the third argument to sqlite3_open_v2(), or if it has
+** been enabled globally using the [SQLITE_CONFIG_URI] option with the
+** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
+** URI filename interpretation is turned off
+** by default, but future releases of SQLite might enable URI filename
+** interpretation by default.  See "[URI filenames]" for additional
+** information.
+**
+** URI filenames are parsed according to RFC 3986. ^If the URI contains an
+** authority, then it must be either an empty string or the string
+** "localhost". ^If the authority is not an empty string or "localhost", an
+** error is returned to the caller. ^The fragment component of a URI, if
+** present, is ignored.
+**
+** ^SQLite uses the path component of the URI as the name of the disk file
+** which contains the database. ^If the path begins with a '/' character,
+** then it is interpreted as an absolute path. ^If the path does not begin
+** with a '/' (meaning that the authority section is omitted from the URI)
+** then the path is interpreted as a relative path.
+** ^(On windows, the first component of an absolute path
+** is a drive specification (e.g. "C:").)^
+**
+** [[core URI query parameters]]
+** The query component of a URI may contain parameters that are interpreted
+** either by SQLite itself, or by a [VFS | custom VFS implementation].
+** SQLite and its built-in [VFSes] interpret the
+** following query parameters:
+**
+** <ul>
+**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
+**     a VFS object that provides the operating system interface that should
+**     be used to access the database file on disk. ^If this option is set to
+**     an empty string the default VFS object is used. ^Specifying an unknown
+**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
+**     present, then the VFS specified by the option takes precedence over
+**     the value passed as the fourth parameter to sqlite3_open_v2().
+**
+**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
+**     "rwc", or "memory". Attempting to set it to any other value is
+**     an error)^.
+**     ^If "ro" is specified, then the database is opened for read-only
+**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
+**     third argument to sqlite3_open_v2(). ^If the mode option is set to
+**     "rw", then the database is opened for read-write (but not create)
+**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
+**     been set. ^Value "rwc" is equivalent to setting both
+**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
+**     set to "memory" then a pure [in-memory database] that never reads
+**     or writes from disk is used. ^It is an error to specify a value for
+**     the mode parameter that is less restrictive than that specified by
+**     the flags passed in the third parameter to sqlite3_open_v2().
+**
+**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
+**     "private". ^Setting it to "shared" is equivalent to setting the
+**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
+**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
+**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
+**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
+**     a URI filename, its value overrides any behavior requested by setting
+**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
+**
+**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
+**     [powersafe overwrite] property does or does not apply to the
+**     storage media on which the database file resides.
+**
+**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
+**     which if set disables file locking in rollback journal modes.  This
+**     is useful for accessing a database on a filesystem that does not
+**     support locking.  Caution:  Database corruption might result if two
+**     or more processes write to the same database and any one of those
+**     processes uses nolock=1.
+**
+**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
+**     parameter that indicates that the database file is stored on
+**     read-only media.  ^When immutable is set, SQLite assumes that the
+**     database file cannot be changed, even by a process with higher
+**     privilege, and so the database is opened read-only and all locking
+**     and change detection is disabled.  Caution: Setting the immutable
+**     property on a database file that does in fact change can result
+**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
+**     See also: [SQLITE_IOCAP_IMMUTABLE].
+**
+** </ul>
+**
+** ^Specifying an unknown parameter in the query component of a URI is not an
+** error.  Future versions of SQLite might understand additional query
+** parameters.  See "[query parameters with special meaning to SQLite]" for
+** additional information.
+**
+** [[URI filename examples]] <h3>URI filename examples</h3>
+**
+** <table border="1" align=center cellpadding=5>
+** <tr><th> URI filenames <th> Results
+** <tr><td> file:data.db <td>
+**          Open the file "data.db" in the current directory.
+** <tr><td> file:/home/fred/data.db<br>
+**          file:///home/fred/data.db <br>
+**          file://localhost/home/fred/data.db <br> <td>
+**          Open the database file "/home/fred/data.db".
+** <tr><td> file://darkstar/home/fred/data.db <td>
+**          An error. "darkstar" is not a recognized authority.
+** <tr><td style="white-space:nowrap">
+**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
+**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
+**          C:. Note that the %20 escaping in this example is not strictly
+**          necessary - space characters can be used literally
+**          in URI filenames.
+** <tr><td> file:data.db?mode=ro&cache=private <td>
+**          Open file "data.db" in the current directory for read-only access.
+**          Regardless of whether or not shared-cache mode is enabled by
+**          default, use a private cache.
+** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
+**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
+**          that uses dot-files in place of posix advisory locking.
+** <tr><td> file:data.db?mode=readonly <td>
+**          An error. "readonly" is not a valid option for the "mode" parameter.
+**          Use "ro" instead:  "file:data.db?mode=ro".
+** </table>
+**
+** ^URI hexadecimal escape sequences (%HH) are supported within the path and
+** query components of a URI. A hexadecimal escape sequence consists of a
+** percent sign - "%" - followed by exactly two hexadecimal digits
+** specifying an octet value. ^Before the path or query components of a
+** URI filename are interpreted, they are encoded using UTF-8 and all
+** hexadecimal escape sequences replaced by a single byte containing the
+** corresponding octet. If this process generates an invalid UTF-8 encoding,
+** the results are undefined.
+**
+** <b>Note to Windows users:</b>  The encoding used for the filename argument
+** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
+** codepage is currently defined.  Filenames containing international
+** characters must be converted to UTF-8 prior to passing them into
+** sqlite3_open() or sqlite3_open_v2().
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
+** features that require the use of temporary files may fail.
+**
+** See also: [sqlite3_temp_directory]
+*/
+SQLITE_API int sqlite3_open(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open16(
+  const void *filename,   /* Database filename (UTF-16) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open_v2(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb,         /* OUT: SQLite db handle */
+  int flags,              /* Flags */
+  const char *zVfs        /* Name of VFS module to use */
+);
+
+/*
+** CAPI3REF: Obtain Values For URI Parameters
+**
+** These are utility routines, useful to [VFS|custom VFS implementations],
+** that check if a database file was a URI that contained a specific query
+** parameter, and if so obtains the value of that query parameter.
+**
+** The first parameter to these interfaces (hereafter referred to
+** as F) must be one of:
+** <ul>
+** <li> A database filename pointer created by the SQLite core and
+** passed into the xOpen() method of a VFS implementation, or
+** <li> A filename obtained from [sqlite3_db_filename()], or
+** <li> A new filename constructed using [sqlite3_create_filename()].
+** </ul>
+** If the F parameter is not one of the above, then the behavior is
+** undefined and probably undesirable.  Older versions of SQLite were
+** more tolerant of invalid F parameters than newer versions.
+**
+** If F is a suitable filename (as described in the previous paragraph)
+** and if P is the name of the query parameter, then
+** sqlite3_uri_parameter(F,P) returns the value of the P
+** parameter if it exists or a NULL pointer if P does not appear as a
+** query parameter on F.  If P is a query parameter of F and it
+** has no explicit value, then sqlite3_uri_parameter(F,P) returns
+** a pointer to an empty string.
+**
+** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
+** parameter and returns true (1) or false (0) according to the value
+** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
+** value of query parameter P is one of "yes", "true", or "on" in any
+** case or if the value begins with a non-zero number.  The
+** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
+** query parameter P is one of "no", "false", or "off" in any case or
+** if the value begins with a numeric zero.  If P is not a query
+** parameter on F or if the value of P does not match any of the
+** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
+**
+** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
+** 64-bit signed integer and returns that integer, or D if P does not
+** exist.  If the value of P is something other than an integer, then
+** zero is returned.
+**
+** The sqlite3_uri_key(F,N) returns a pointer to the name (not
+** the value) of the N-th query parameter for filename F, or a NULL
+** pointer if N is less than zero or greater than the number of query
+** parameters minus 1.  The N value is zero-based so N should be 0 to obtain
+** the name of the first query parameter, 1 for the second parameter, and
+** so forth.
+**
+** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
+** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
+** is not a database file pathname pointer that the SQLite core passed
+** into the xOpen VFS method, then the behavior of this routine is undefined
+** and probably undesirable.
+**
+** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
+** parameter can also be the name of a rollback journal file or WAL file
+** in addition to the main database file.  Prior to version 3.31.0, these
+** routines would only work if F was the name of the main database file.
+** When the F parameter is the name of the rollback journal or WAL file,
+** it has access to all the same query parameters as were found on the
+** main database file.
+**
+** See the [URI filename] documentation for additional information.
+*/
+SQLITE_API const char *sqlite3_uri_parameter(sqlite3_filename z, const char *zParam);
+SQLITE_API int sqlite3_uri_boolean(sqlite3_filename z, const char *zParam, int bDefault);
+SQLITE_API sqlite3_int64 sqlite3_uri_int64(sqlite3_filename, const char*, sqlite3_int64);
+SQLITE_API const char *sqlite3_uri_key(sqlite3_filename z, int N);
+
+/*
+** CAPI3REF:  Translate filenames
+**
+** These routines are available to [VFS|custom VFS implementations] for
+** translating filenames between the main database file, the journal file,
+** and the WAL file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
+** returns the name of the corresponding database file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** passed by the SQLite core into the VFS, or if F is a database filename
+** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
+** returns the name of the corresponding rollback journal file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** that was passed by the SQLite core into the VFS, or if F is a database
+** filename obtained from [sqlite3_db_filename()], then
+** sqlite3_filename_wal(F) returns the name of the corresponding
+** WAL file.
+**
+** In all of the above, if F is not the name of a database, journal or WAL
+** filename passed into the VFS from the SQLite core and F is not the
+** return value from [sqlite3_db_filename()], then the result is
+** undefined and is likely a memory access violation.
+*/
+SQLITE_API const char *sqlite3_filename_database(sqlite3_filename);
+SQLITE_API const char *sqlite3_filename_journal(sqlite3_filename);
+SQLITE_API const char *sqlite3_filename_wal(sqlite3_filename);
+
+/*
+** CAPI3REF:  Database File Corresponding To A Journal
+**
+** ^If X is the name of a rollback or WAL-mode journal file that is
+** passed into the xOpen method of [sqlite3_vfs], then
+** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
+** object that represents the main database file.
+**
+** This routine is intended for use in custom [VFS] implementations
+** only.  It is not a general-purpose interface.
+** The argument sqlite3_file_object(X) must be a filename pointer that
+** has been passed into [sqlite3_vfs].xOpen method where the
+** flags parameter to xOpen contains one of the bits
+** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL].  Any other use
+** of this routine results in undefined and probably undesirable
+** behavior.
+*/
+SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
+
+/*
+** CAPI3REF: Create and Destroy VFS Filenames
+**
+** These interfaces are provided for use by [VFS shim] implementations and
+** are not useful outside of that context.
+**
+** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
+** database filename D with corresponding journal file J and WAL file W and
+** with N URI parameters key/values pairs in the array P.  The result from
+** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
+** is safe to pass to routines like:
+** <ul>
+** <li> [sqlite3_uri_parameter()],
+** <li> [sqlite3_uri_boolean()],
+** <li> [sqlite3_uri_int64()],
+** <li> [sqlite3_uri_key()],
+** <li> [sqlite3_filename_database()],
+** <li> [sqlite3_filename_journal()], or
+** <li> [sqlite3_filename_wal()].
+** </ul>
+** If a memory allocation error occurs, sqlite3_create_filename() might
+** return a NULL pointer.  The memory obtained from sqlite3_create_filename(X)
+** must be released by a corresponding call to sqlite3_free_filename(Y).
+**
+** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
+** of 2*N pointers to strings.  Each pair of pointers in this array corresponds
+** to a key and value for a query parameter.  The P parameter may be a NULL
+** pointer if N is zero.  None of the 2*N pointers in the P array may be
+** NULL pointers and key pointers should not be empty strings.
+** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
+** be NULL pointers, though they can be empty strings.
+**
+** The sqlite3_free_filename(Y) routine releases a memory allocation
+** previously obtained from sqlite3_create_filename().  Invoking
+** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
+**
+** If the Y parameter to sqlite3_free_filename(Y) is anything other
+** than a NULL pointer or a pointer previously acquired from
+** sqlite3_create_filename(), then bad things such as heap
+** corruption or segfaults may occur. The value Y should not be
+** used again after sqlite3_free_filename(Y) has been called.  This means
+** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
+** then the corresponding [sqlite3_module.xClose() method should also be
+** invoked prior to calling sqlite3_free_filename(Y).
+*/
+SQLITE_API sqlite3_filename sqlite3_create_filename(
+  const char *zDatabase,
+  const char *zJournal,
+  const char *zWal,
+  int nParam,
+  const char **azParam
+);
+SQLITE_API void sqlite3_free_filename(sqlite3_filename);
+
+/*
+** CAPI3REF: Error Codes And Messages
+** METHOD: sqlite3
+**
+** ^If the most recent sqlite3_* API call associated with
+** [database connection] D failed, then the sqlite3_errcode(D) interface
+** returns the numeric [result code] or [extended result code] for that
+** API call.
+** ^The sqlite3_extended_errcode()
+** interface is the same except that it always returns the
+** [extended result code] even when extended result codes are
+** disabled.
+**
+** The values returned by sqlite3_errcode() and/or
+** sqlite3_extended_errcode() might change with each API call.
+** Except, there are some interfaces that are guaranteed to never
+** change the value of the error code.  The error-code preserving
+** interfaces include the following:
+**
+** <ul>
+** <li> sqlite3_errcode()
+** <li> sqlite3_extended_errcode()
+** <li> sqlite3_errmsg()
+** <li> sqlite3_errmsg16()
+** <li> sqlite3_error_offset()
+** </ul>
+**
+** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
+** text that describes the error, as either UTF-8 or UTF-16 respectively,
+** or NULL if no error message is available.
+** (See how SQLite handles [invalid UTF] for exceptions to this rule.)
+** ^(Memory to hold the error message string is managed internally.
+** The application does not need to worry about freeing the result.
+** However, the error string might be overwritten or deallocated by
+** subsequent calls to other SQLite interface functions.)^
+**
+** ^The sqlite3_errstr(E) interface returns the English-language text
+** that describes the [result code] E, as UTF-8, or NULL if E is not an
+** result code for which a text error message is available.
+** ^(Memory to hold the error message string is managed internally
+** and must not be freed by the application)^.
+**
+** ^If the most recent error references a specific token in the input
+** SQL, the sqlite3_error_offset() interface returns the byte offset
+** of the start of that token.  ^The byte offset returned by
+** sqlite3_error_offset() assumes that the input SQL is UTF8.
+** ^If the most recent error does not reference a specific token in the input
+** SQL, then the sqlite3_error_offset() function returns -1.
+**
+** When the serialized [threading mode] is in use, it might be the
+** case that a second error occurs on a separate thread in between
+** the time of the first error and the call to these interfaces.
+** When that happens, the second error will be reported since these
+** interfaces always report the most recent result.  To avoid
+** this, each thread can obtain exclusive use of the [database connection] D
+** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
+** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
+** all calls to the interfaces listed here are completed.
+**
+** If an interface fails with SQLITE_MISUSE, that means the interface
+** was invoked incorrectly by the application.  In that case, the
+** error code and message may or may not be set.
+*/
+SQLITE_API int sqlite3_errcode(sqlite3 *db);
+SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
+SQLITE_API const char *sqlite3_errmsg(sqlite3*);
+SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
+SQLITE_API const char *sqlite3_errstr(int);
+SQLITE_API int sqlite3_error_offset(sqlite3 *db);
+
+/*
+** CAPI3REF: Prepared Statement Object
+** KEYWORDS: {prepared statement} {prepared statements}
+**
+** An instance of this object represents a single SQL statement that
+** has been compiled into binary form and is ready to be evaluated.
+**
+** Think of each SQL statement as a separate computer program.  The
+** original SQL text is source code.  A prepared statement object
+** is the compiled object code.  All SQL must be converted into a
+** prepared statement before it can be run.
+**
+** The life-cycle of a prepared statement object usually goes like this:
+**
+** <ol>
+** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
+** <li> Bind values to [parameters] using the sqlite3_bind_*()
+**      interfaces.
+** <li> Run the SQL by calling [sqlite3_step()] one or more times.
+** <li> Reset the prepared statement using [sqlite3_reset()] then go back
+**      to step 2.  Do this zero or more times.
+** <li> Destroy the object using [sqlite3_finalize()].
+** </ol>
+*/
+typedef struct sqlite3_stmt sqlite3_stmt;
+
+/*
+** CAPI3REF: Run-time Limits
+** METHOD: sqlite3
+**
+** ^(This interface allows the size of various constructs to be limited
+** on a connection by connection basis.  The first parameter is the
+** [database connection] whose limit is to be set or queried.  The
+** second parameter is one of the [limit categories] that define a
+** class of constructs to be size limited.  The third parameter is the
+** new limit for that construct.)^
+**
+** ^If the new limit is a negative number, the limit is unchanged.
+** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
+** [limits | hard upper bound]
+** set at compile-time by a C preprocessor macro called
+** [limits | SQLITE_MAX_<i>NAME</i>].
+** (The "_LIMIT_" in the name is changed to "_MAX_".))^
+** ^Attempts to increase a limit above its hard upper bound are
+** silently truncated to the hard upper bound.
+**
+** ^Regardless of whether or not the limit was changed, the
+** [sqlite3_limit()] interface returns the prior value of the limit.
+** ^Hence, to find the current value of a limit without changing it,
+** simply invoke this interface with the third parameter set to -1.
+**
+** Run-time limits are intended for use in applications that manage
+** both their own internal database and also databases that are controlled
+** by untrusted external sources.  An example application might be a
+** web browser that has its own databases for storing history and
+** separate databases controlled by JavaScript applications downloaded
+** off the Internet.  The internal databases can be given the
+** large, default limits.  Databases managed by external sources can
+** be given much smaller limits designed to prevent a denial of service
+** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
+** interface to further control untrusted SQL.  The size of the database
+** created by an untrusted script can be contained using the
+** [max_page_count] [PRAGMA].
+**
+** New run-time limit categories may be added in future releases.
+*/
+SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
+
+/*
+** CAPI3REF: Run-Time Limit Categories
+** KEYWORDS: {limit category} {*limit categories}
+**
+** These constants define various performance limits
+** that can be lowered at run-time using [sqlite3_limit()].
+** The synopsis of the meanings of the various limits is shown below.
+** Additional information is available at [limits | Limits in SQLite].
+**
+** <dl>
+** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
+** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
+**
+** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
+** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
+**
+** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
+** <dd>The maximum number of columns in a table definition or in the
+** result set of a [SELECT] or the maximum number of columns in an index
+** or in an ORDER BY or GROUP BY clause.</dd>)^
+**
+** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
+** <dd>The maximum depth of the parse tree on any expression.</dd>)^
+**
+** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
+** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
+**
+** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
+** <dd>The maximum number of instructions in a virtual machine program
+** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
+** the equivalent tries to allocate space for more than this many opcodes
+** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
+**
+** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
+** <dd>The maximum number of arguments on a function.</dd>)^
+**
+** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
+** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
+**
+** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
+** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
+** <dd>The maximum length of the pattern argument to the [LIKE] or
+** [GLOB] operators.</dd>)^
+**
+** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
+** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
+** <dd>The maximum index number of any [parameter] in an SQL statement.)^
+**
+** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
+** <dd>The maximum depth of recursion for triggers.</dd>)^
+**
+** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
+** <dd>The maximum number of auxiliary worker threads that a single
+** [prepared statement] may start.</dd>)^
+** </dl>
+*/
+#define SQLITE_LIMIT_LENGTH                    0
+#define SQLITE_LIMIT_SQL_LENGTH                1
+#define SQLITE_LIMIT_COLUMN                    2
+#define SQLITE_LIMIT_EXPR_DEPTH                3
+#define SQLITE_LIMIT_COMPOUND_SELECT           4
+#define SQLITE_LIMIT_VDBE_OP                   5
+#define SQLITE_LIMIT_FUNCTION_ARG              6
+#define SQLITE_LIMIT_ATTACHED                  7
+#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
+#define SQLITE_LIMIT_VARIABLE_NUMBER           9
+#define SQLITE_LIMIT_TRIGGER_DEPTH            10
+#define SQLITE_LIMIT_WORKER_THREADS           11
+
+/*
+** CAPI3REF: Prepare Flags
+**
+** These constants define various flags that can be passed into
+** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
+** [sqlite3_prepare16_v3()] interfaces.
+**
+** New flags may be added in future releases of SQLite.
+**
+** <dl>
+** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
+** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
+** that the prepared statement will be retained for a long time and
+** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
+** and [sqlite3_prepare16_v3()] assume that the prepared statement will
+** be used just once or at most a few times and then destroyed using
+** [sqlite3_finalize()] relatively soon. The current implementation acts
+** on this hint by avoiding the use of [lookaside memory] so as not to
+** deplete the limited store of lookaside memory. Future versions of
+** SQLite may act on this hint differently.
+**
+** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
+** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
+** to be required for any prepared statement that wanted to use the
+** [sqlite3_normalized_sql()] interface.  However, the
+** [sqlite3_normalized_sql()] interface is now available to all
+** prepared statements, regardless of whether or not they use this
+** flag.
+**
+** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
+** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
+** to return an error (error code SQLITE_ERROR) if the statement uses
+** any virtual tables.
+**
+** [[SQLITE_PREPARE_DONT_LOG]] <dt>SQLITE_PREPARE_DONT_LOG</dt>
+** <dd>The SQLITE_PREPARE_DONT_LOG flag prevents SQL compiler
+** errors from being sent to the error log defined by
+** [SQLITE_CONFIG_LOG].  This can be used, for example, to do test
+** compiles to see if some SQL syntax is well-formed, without generating
+** messages on the global error log when it is not.  If the test compile
+** fails, the sqlite3_prepare_v3() call returns the same error indications
+** with or without this flag; it just omits the call to [sqlite3_log()] that
+** logs the error.
+** </dl>
+*/
+#define SQLITE_PREPARE_PERSISTENT              0x01
+#define SQLITE_PREPARE_NORMALIZE               0x02
+#define SQLITE_PREPARE_NO_VTAB                 0x04
+#define SQLITE_PREPARE_DONT_LOG                0x10
+
+/*
+** CAPI3REF: Compiling An SQL Statement
+** KEYWORDS: {SQL statement compiler}
+** METHOD: sqlite3
+** CONSTRUCTOR: sqlite3_stmt
+**
+** To execute an SQL statement, it must first be compiled into a byte-code
+** program using one of these routines.  Or, in other words, these routines
+** are constructors for the [prepared statement] object.
+**
+** The preferred routine to use is [sqlite3_prepare_v2()].  The
+** [sqlite3_prepare()] interface is legacy and should be avoided.
+** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
+** for special purposes.
+**
+** The use of the UTF-8 interfaces is preferred, as SQLite currently
+** does all parsing using UTF-8.  The UTF-16 interfaces are provided
+** as a convenience.  The UTF-16 interfaces work by converting the
+** input text into UTF-8, then invoking the corresponding UTF-8 interface.
+**
+** The first argument, "db", is a [database connection] obtained from a
+** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
+** [sqlite3_open16()].  The database connection must not have been closed.
+**
+** The second argument, "zSql", is the statement to be compiled, encoded
+** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
+** and sqlite3_prepare_v3()
+** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
+** and sqlite3_prepare16_v3() use UTF-16.
+**
+** ^If the nByte argument is negative, then zSql is read up to the
+** first zero terminator. ^If nByte is positive, then it is the maximum
+** number of bytes read from zSql.  When nByte is positive, zSql is read
+** up to the first zero terminator or until the nByte bytes have been read,
+** whichever comes first.  ^If nByte is zero, then no prepared
+** statement is generated.
+** If the caller knows that the supplied string is nul-terminated, then
+** there is a small performance advantage to passing an nByte parameter that
+** is the number of bytes in the input string <i>including</i>
+** the nul-terminator.
+** Note that nByte measure the length of the input in bytes, not
+** characters, even for the UTF-16 interfaces.
+**
+** ^If pzTail is not NULL then *pzTail is made to point to the first byte
+** past the end of the first SQL statement in zSql.  These routines only
+** compile the first statement in zSql, so *pzTail is left pointing to
+** what remains uncompiled.
+**
+** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
+** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
+** to NULL.  ^If the input text contains no SQL (if the input is an empty
+** string or a comment) then *ppStmt is set to NULL.
+** The calling procedure is responsible for deleting the compiled
+** SQL statement using [sqlite3_finalize()] after it has finished with it.
+** ppStmt may not be NULL.
+**
+** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
+** otherwise an [error code] is returned.
+**
+** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
+** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
+** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
+** are retained for backwards compatibility, but their use is discouraged.
+** ^In the "vX" interfaces, the prepared statement
+** that is returned (the [sqlite3_stmt] object) contains a copy of the
+** original SQL text. This causes the [sqlite3_step()] interface to
+** behave differently in three ways:
+**
+** <ol>
+** <li>
+** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
+** always used to do, [sqlite3_step()] will automatically recompile the SQL
+** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
+** retries will occur before sqlite3_step() gives up and returns an error.
+** </li>
+**
+** <li>
+** ^When an error occurs, [sqlite3_step()] will return one of the detailed
+** [error codes] or [extended error codes].  ^The legacy behavior was that
+** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
+** and the application would have to make a second call to [sqlite3_reset()]
+** in order to find the underlying cause of the problem. With the "v2" prepare
+** interfaces, the underlying reason for the error is returned immediately.
+** </li>
+**
+** <li>
+** ^If the specific value bound to a [parameter | host parameter] in the
+** WHERE clause might influence the choice of query plan for a statement,
+** then the statement will be automatically recompiled, as if there had been
+** a schema change, on the first [sqlite3_step()] call following any change
+** to the [sqlite3_bind_text | bindings] of that [parameter].
+** ^The specific value of a WHERE-clause [parameter] might influence the
+** choice of query plan if the parameter is the left-hand side of a [LIKE]
+** or [GLOB] operator or if the parameter is compared to an indexed column
+** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
+** </li>
+** </ol>
+**
+** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
+** the extra prepFlags parameter, which is a bit array consisting of zero or
+** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
+** sqlite3_prepare_v2() interface works exactly the same as
+** sqlite3_prepare_v3() with a zero prepFlags parameter.
+*/
+SQLITE_API int sqlite3_prepare(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare_v2(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare_v3(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16_v2(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16_v3(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+
+/*
+** CAPI3REF: Retrieving Statement SQL
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
+** SQL text used to create [prepared statement] P if P was
+** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
+** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
+** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
+** string containing the SQL text of prepared statement P with
+** [bound parameters] expanded.
+** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
+** string containing the normalized SQL text of prepared statement P.  The
+** semantics used to normalize a SQL statement are unspecified and subject
+** to change.  At a minimum, literal values will be replaced with suitable
+** placeholders.
+**
+** ^(For example, if a prepared statement is created using the SQL
+** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
+** and parameter :xyz is unbound, then sqlite3_sql() will return
+** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
+** will return "SELECT 2345,NULL".)^
+**
+** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
+** is available to hold the result, or if the result would exceed the
+** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
+**
+** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
+** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
+** option causes sqlite3_expanded_sql() to always return NULL.
+**
+** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
+** are managed by SQLite and are automatically freed when the prepared
+** statement is finalized.
+** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
+** is obtained from [sqlite3_malloc()] and must be freed by the application
+** by passing it to [sqlite3_free()].
+**
+** ^The sqlite3_normalized_sql() interface is only available if
+** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
+*/
+SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
+SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
+#ifdef SQLITE_ENABLE_NORMALIZE
+SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
+#endif
+
+/*
+** CAPI3REF: Determine If An SQL Statement Writes The Database
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
+** and only if the [prepared statement] X makes no direct changes to
+** the content of the database file.
+**
+** Note that [application-defined SQL functions] or
+** [virtual tables] might change the database indirectly as a side effect.
+** ^(For example, if an application defines a function "eval()" that
+** calls [sqlite3_exec()], then the following SQL statement would
+** change the database file through side-effects:
+**
+** <blockquote><pre>
+**    SELECT eval('DELETE FROM t1') FROM t2;
+** </pre></blockquote>
+**
+** But because the [SELECT] statement does not change the database file
+** directly, sqlite3_stmt_readonly() would still return true.)^
+**
+** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
+** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
+** since the statements themselves do not actually modify the database but
+** rather they control the timing of when other statements modify the
+** database.  ^The [ATTACH] and [DETACH] statements also cause
+** sqlite3_stmt_readonly() to return true since, while those statements
+** change the configuration of a database connection, they do not make
+** changes to the content of the database files on disk.
+** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
+** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
+** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
+** sqlite3_stmt_readonly() returns false for those commands.
+**
+** ^This routine returns false if there is any possibility that the
+** statement might change the database file.  ^A false return does
+** not guarantee that the statement will change the database file.
+** ^For example, an UPDATE statement might have a WHERE clause that
+** makes it a no-op, but the sqlite3_stmt_readonly() result would still
+** be false.  ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
+** read-only no-op if the table already exists, but
+** sqlite3_stmt_readonly() still returns false for such a statement.
+**
+** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
+** statement, then sqlite3_stmt_readonly(X) returns the same value as
+** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
+*/
+SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
+** prepared statement S is an EXPLAIN statement, or 2 if the
+** statement S is an EXPLAIN QUERY PLAN.
+** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
+** an ordinary statement or a NULL pointer.
+*/
+SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Change The EXPLAIN Setting For A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** The sqlite3_stmt_explain(S,E) interface changes the EXPLAIN
+** setting for [prepared statement] S.  If E is zero, then S becomes
+** a normal prepared statement.  If E is 1, then S behaves as if
+** its SQL text began with "[EXPLAIN]".  If E is 2, then S behaves as if
+** its SQL text began with "[EXPLAIN QUERY PLAN]".
+**
+** Calling sqlite3_stmt_explain(S,E) might cause S to be reprepared.
+** SQLite tries to avoid a reprepare, but a reprepare might be necessary
+** on the first transition into EXPLAIN or EXPLAIN QUERY PLAN mode.
+**
+** Because of the potential need to reprepare, a call to
+** sqlite3_stmt_explain(S,E) will fail with SQLITE_ERROR if S cannot be
+** reprepared because it was created using [sqlite3_prepare()] instead of
+** the newer [sqlite3_prepare_v2()] or [sqlite3_prepare_v3()] interfaces and
+** hence has no saved SQL text with which to reprepare.
+**
+** Changing the explain setting for a prepared statement does not change
+** the original SQL text for the statement.  Hence, if the SQL text originally
+** began with EXPLAIN or EXPLAIN QUERY PLAN, but sqlite3_stmt_explain(S,0)
+** is called to convert the statement into an ordinary statement, the EXPLAIN
+** or EXPLAIN QUERY PLAN keywords will still appear in the sqlite3_sql(S)
+** output, even though the statement now acts like a normal SQL statement.
+**
+** This routine returns SQLITE_OK if the explain mode is successfully
+** changed, or an error code if the explain mode could not be changed.
+** The explain mode cannot be changed while a statement is active.
+** Hence, it is good practice to call [sqlite3_reset(S)]
+** immediately prior to calling sqlite3_stmt_explain(S,E).
+*/
+SQLITE_API int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode);
+
+/*
+** CAPI3REF: Determine If A Prepared Statement Has Been Reset
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
+** [prepared statement] S has been stepped at least once using
+** [sqlite3_step(S)] but has neither run to completion (returned
+** [SQLITE_DONE] from [sqlite3_step(S)]) nor
+** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
+** interface returns false if S is a NULL pointer.  If S is not a
+** NULL pointer and is not a pointer to a valid [prepared statement]
+** object, then the behavior is undefined and probably undesirable.
+**
+** This interface can be used in combination [sqlite3_next_stmt()]
+** to locate all prepared statements associated with a database
+** connection that are in need of being reset.  This can be used,
+** for example, in diagnostic routines to search for prepared
+** statements that are holding a transaction open.
+*/
+SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Dynamically Typed Value Object
+** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
+**
+** SQLite uses the sqlite3_value object to represent all values
+** that can be stored in a database table. SQLite uses dynamic typing
+** for the values it stores.  ^Values stored in sqlite3_value objects
+** can be integers, floating point values, strings, BLOBs, or NULL.
+**
+** An sqlite3_value object may be either "protected" or "unprotected".
+** Some interfaces require a protected sqlite3_value.  Other interfaces
+** will accept either a protected or an unprotected sqlite3_value.
+** Every interface that accepts sqlite3_value arguments specifies
+** whether or not it requires a protected sqlite3_value.  The
+** [sqlite3_value_dup()] interface can be used to construct a new
+** protected sqlite3_value from an unprotected sqlite3_value.
+**
+** The terms "protected" and "unprotected" refer to whether or not
+** a mutex is held.  An internal mutex is held for a protected
+** sqlite3_value object but no mutex is held for an unprotected
+** sqlite3_value object.  If SQLite is compiled to be single-threaded
+** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
+** or if SQLite is run in one of reduced mutex modes
+** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
+** then there is no distinction between protected and unprotected
+** sqlite3_value objects and they can be used interchangeably.  However,
+** for maximum code portability it is recommended that applications
+** still make the distinction between protected and unprotected
+** sqlite3_value objects even when not strictly required.
+**
+** ^The sqlite3_value objects that are passed as parameters into the
+** implementation of [application-defined SQL functions] are protected.
+** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
+** are protected.
+** ^The sqlite3_value object returned by
+** [sqlite3_column_value()] is unprotected.
+** Unprotected sqlite3_value objects may only be used as arguments
+** to [sqlite3_result_value()], [sqlite3_bind_value()], and
+** [sqlite3_value_dup()].
+** The [sqlite3_value_blob | sqlite3_value_type()] family of
+** interfaces require protected sqlite3_value objects.
+*/
+typedef struct sqlite3_value sqlite3_value;
+
+/*
+** CAPI3REF: SQL Function Context Object
+**
+** The context in which an SQL function executes is stored in an
+** sqlite3_context object.  ^A pointer to an sqlite3_context object
+** is always first parameter to [application-defined SQL functions].
+** The application-defined SQL function implementation will pass this
+** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
+** [sqlite3_aggregate_context()], [sqlite3_user_data()],
+** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
+** and/or [sqlite3_set_auxdata()].
+*/
+typedef struct sqlite3_context sqlite3_context;
+
+/*
+** CAPI3REF: Binding Values To Prepared Statements
+** KEYWORDS: {host parameter} {host parameters} {host parameter name}
+** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
+** METHOD: sqlite3_stmt
+**
+** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
+** literals may be replaced by a [parameter] that matches one of following
+** templates:
+**
+** <ul>
+** <li>  ?
+** <li>  ?NNN
+** <li>  :VVV
+** <li>  @VVV
+** <li>  $VVV
+** </ul>
+**
+** In the templates above, NNN represents an integer literal,
+** and VVV represents an alphanumeric identifier.)^  ^The values of these
+** parameters (also called "host parameter names" or "SQL parameters")
+** can be set using the sqlite3_bind_*() routines defined here.
+**
+** ^The first argument to the sqlite3_bind_*() routines is always
+** a pointer to the [sqlite3_stmt] object returned from
+** [sqlite3_prepare_v2()] or its variants.
+**
+** ^The second argument is the index of the SQL parameter to be set.
+** ^The leftmost SQL parameter has an index of 1.  ^When the same named
+** SQL parameter is used more than once, second and subsequent
+** occurrences have the same index as the first occurrence.
+** ^The index for named parameters can be looked up using the
+** [sqlite3_bind_parameter_index()] API if desired.  ^The index
+** for "?NNN" parameters is the value of NNN.
+** ^The NNN value must be between 1 and the [sqlite3_limit()]
+** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
+**
+** ^The third argument is the value to bind to the parameter.
+** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
+** is ignored and the end result is the same as sqlite3_bind_null().
+** ^If the third parameter to sqlite3_bind_text() is not NULL, then
+** it should be a pointer to well-formed UTF8 text.
+** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
+** it should be a pointer to well-formed UTF16 text.
+** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
+** it should be a pointer to a well-formed unicode string that is
+** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
+** otherwise.
+**
+** [[byte-order determination rules]] ^The byte-order of
+** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
+** found in first character, which is removed, or in the absence of a BOM
+** the byte order is the native byte order of the host
+** machine for sqlite3_bind_text16() or the byte order specified in
+** the 6th parameter for sqlite3_bind_text64().)^
+** ^If UTF16 input text contains invalid unicode
+** characters, then SQLite might change those invalid characters
+** into the unicode replacement character: U+FFFD.
+**
+** ^(In those routines that have a fourth argument, its value is the
+** number of bytes in the parameter.  To be clear: the value is the
+** number of <u>bytes</u> in the value, not the number of characters.)^
+** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** is negative, then the length of the string is
+** the number of bytes up to the first zero terminator.
+** If the fourth parameter to sqlite3_bind_blob() is negative, then
+** the behavior is undefined.
+** If a non-negative fourth parameter is provided to sqlite3_bind_text()
+** or sqlite3_bind_text16() or sqlite3_bind_text64() then
+** that parameter must be the byte offset
+** where the NUL terminator would occur assuming the string were NUL
+** terminated.  If any NUL characters occurs at byte offsets less than
+** the value of the fourth parameter then the resulting string value will
+** contain embedded NULs.  The result of expressions involving strings
+** with embedded NULs is undefined.
+**
+** ^The fifth argument to the BLOB and string binding interfaces controls
+** or indicates the lifetime of the object referenced by the third parameter.
+** These three options exist:
+** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
+** with it may be passed. ^It is called to dispose of the BLOB or string even
+** if the call to the bind API fails, except the destructor is not called if
+** the third parameter is a NULL pointer or the fourth parameter is negative.
+** ^ (2) The special constant, [SQLITE_STATIC], may be passed to indicate that
+** the application remains responsible for disposing of the object. ^In this
+** case, the object and the provided pointer to it must remain valid until
+** either the prepared statement is finalized or the same SQL parameter is
+** bound to something else, whichever occurs sooner.
+** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
+** object is to be copied prior to the return from sqlite3_bind_*(). ^The
+** object and pointer to it must remain valid until then. ^SQLite will then
+** manage the lifetime of its private copy.
+**
+** ^The sixth argument to sqlite3_bind_text64() must be one of
+** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
+** to specify the encoding of the text in the third parameter.  If
+** the sixth argument to sqlite3_bind_text64() is not one of the
+** allowed values shown above, or if the text encoding is different
+** from the encoding specified by the sixth parameter, then the behavior
+** is undefined.
+**
+** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
+** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
+** (just an integer to hold its size) while it is being processed.
+** Zeroblobs are intended to serve as placeholders for BLOBs whose
+** content is later written using
+** [sqlite3_blob_open | incremental BLOB I/O] routines.
+** ^A negative value for the zeroblob results in a zero-length BLOB.
+**
+** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
+** [prepared statement] S to have an SQL value of NULL, but to also be
+** associated with the pointer P of type T.  ^D is either a NULL pointer or
+** a pointer to a destructor function for P. ^SQLite will invoke the
+** destructor D with a single argument of P when it is finished using
+** P.  The T parameter should be a static string, preferably a string
+** literal. The sqlite3_bind_pointer() routine is part of the
+** [pointer passing interface] added for SQLite 3.20.0.
+**
+** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
+** for the [prepared statement] or with a prepared statement for which
+** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
+** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
+** routine is passed a [prepared statement] that has been finalized, the
+** result is undefined and probably harmful.
+**
+** ^Bindings are not cleared by the [sqlite3_reset()] routine.
+** ^Unbound parameters are interpreted as NULL.
+**
+** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
+** [error code] if anything goes wrong.
+** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
+** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
+** [SQLITE_MAX_LENGTH].
+** ^[SQLITE_RANGE] is returned if the parameter
+** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
+**
+** See also: [sqlite3_bind_parameter_count()],
+** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
+SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
+                        void(*)(void*));
+SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
+SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
+SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
+SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
+SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
+SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
+SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
+                         void(*)(void*), unsigned char encoding);
+SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
+SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
+SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
+SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
+
+/*
+** CAPI3REF: Number Of SQL Parameters
+** METHOD: sqlite3_stmt
+**
+** ^This routine can be used to find the number of [SQL parameters]
+** in a [prepared statement].  SQL parameters are tokens of the
+** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
+** placeholders for values that are [sqlite3_bind_blob | bound]
+** to the parameters at a later time.
+**
+** ^(This routine actually returns the index of the largest (rightmost)
+** parameter. For all forms except ?NNN, this will correspond to the
+** number of unique parameters.  If parameters of the ?NNN form are used,
+** there may be gaps in the list.)^
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_name()], and
+** [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Name Of A Host Parameter
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_bind_parameter_name(P,N) interface returns
+** the name of the N-th [SQL parameter] in the [prepared statement] P.
+** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** respectively.
+** In other words, the initial ":" or "$" or "@" or "?"
+** is included as part of the name.)^
+** ^Parameters of the form "?" without a following integer have no name
+** and are referred to as "nameless" or "anonymous parameters".
+**
+** ^The first host parameter has an index of 1, not 0.
+**
+** ^If the value N is out of range or if the N-th parameter is
+** nameless, then NULL is returned.  ^The returned string is
+** always in UTF-8 encoding even if the named parameter was
+** originally specified as UTF-16 in [sqlite3_prepare16()],
+** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
+
+/*
+** CAPI3REF: Index Of A Parameter With A Given Name
+** METHOD: sqlite3_stmt
+**
+** ^Return the index of an SQL parameter given its name.  ^The
+** index value returned is suitable for use as the second
+** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
+** is returned if no matching parameter is found.  ^The parameter
+** name must be given in UTF-8 even if the original statement
+** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
+** [sqlite3_prepare16_v3()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_name()].
+*/
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
+
+/*
+** CAPI3REF: Reset All Bindings On A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
+** the [sqlite3_bind_blob | bindings] on a [prepared statement].
+** ^Use this routine to reset all host parameters to NULL.
+*/
+SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number Of Columns In A Result Set
+** METHOD: sqlite3_stmt
+**
+** ^Return the number of columns in the result set returned by the
+** [prepared statement]. ^If this routine returns 0, that means the
+** [prepared statement] returns no data (for example an [UPDATE]).
+** ^However, just because this routine returns a positive number does not
+** mean that one or more rows of data will be returned.  ^A SELECT statement
+** will always have a positive sqlite3_column_count() but depending on the
+** WHERE clause constraints and the table content, it might return no rows.
+**
+** See also: [sqlite3_data_count()]
+*/
+SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Column Names In A Result Set
+** METHOD: sqlite3_stmt
+**
+** ^These routines return the name assigned to a particular column
+** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
+** interface returns a pointer to a zero-terminated UTF-8 string
+** and sqlite3_column_name16() returns a pointer to a zero-terminated
+** UTF-16 string.  ^The first parameter is the [prepared statement]
+** that implements the [SELECT] statement. ^The second parameter is the
+** column number.  ^The leftmost column is number 0.
+**
+** ^The returned string pointer is valid until either the [prepared statement]
+** is destroyed by [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the next call to
+** sqlite3_column_name() or sqlite3_column_name16() on the same column.
+**
+** ^If sqlite3_malloc() fails during the processing of either routine
+** (for example during a conversion from UTF-8 to UTF-16) then a
+** NULL pointer is returned.
+**
+** ^The name of a result column is the value of the "AS" clause for
+** that column, if there is an AS clause.  If there is no AS clause
+** then the name of the column is unspecified and may change from
+** one release of SQLite to the next.
+*/
+SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
+SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
+
+/*
+** CAPI3REF: Source Of Data In A Query Result
+** METHOD: sqlite3_stmt
+**
+** ^These routines provide a means to determine the database, table, and
+** table column that is the origin of a particular result column in
+** [SELECT] statement.
+** ^The name of the database or table or column can be returned as
+** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
+** the database name, the _table_ routines return the table name, and
+** the origin_ routines return the column name.
+** ^The returned string is valid until the [prepared statement] is destroyed
+** using [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the same information is requested
+** again in a different encoding.
+**
+** ^The names returned are the original un-aliased names of the
+** database, table, and column.
+**
+** ^The first argument to these interfaces is a [prepared statement].
+** ^These functions return information about the Nth result column returned by
+** the statement, where N is the second function argument.
+** ^The left-most column is column 0 for these routines.
+**
+** ^If the Nth column returned by the statement is an expression or
+** subquery and is not a column value, then all of these functions return
+** NULL.  ^These routines might also return NULL if a memory allocation error
+** occurs.  ^Otherwise, they return the name of the attached database, table,
+** or column that query result column was extracted from.
+**
+** ^As with all other SQLite APIs, those whose names end with "16" return
+** UTF-16 encoded strings and the other functions return UTF-8.
+**
+** ^These APIs are only available if the library was compiled with the
+** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
+**
+** If two or more threads call one or more
+** [sqlite3_column_database_name | column metadata interfaces]
+** for the same [prepared statement] and result column
+** at the same time then the results are undefined.
+*/
+SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
+
+/*
+** CAPI3REF: Declared Datatype Of A Query Result
+** METHOD: sqlite3_stmt
+**
+** ^(The first parameter is a [prepared statement].
+** If this statement is a [SELECT] statement and the Nth column of the
+** returned result set of that [SELECT] is a table column (not an
+** expression or subquery) then the declared type of the table
+** column is returned.)^  ^If the Nth column of the result set is an
+** expression or subquery, then a NULL pointer is returned.
+** ^The returned string is always UTF-8 encoded.
+**
+** ^(For example, given the database schema:
+**
+** CREATE TABLE t1(c1 VARIANT);
+**
+** and the following statement to be compiled:
+**
+** SELECT c1 + 1, c1 FROM t1;
+**
+** this routine would return the string "VARIANT" for the second result
+** column (i==1), and a NULL pointer for the first result column (i==0).)^
+**
+** ^SQLite uses dynamic run-time typing.  ^So just because a column
+** is declared to contain a particular type does not mean that the
+** data stored in that column is of the declared type.  SQLite is
+** strongly typed, but the typing is dynamic not static.  ^Type
+** is associated with individual values, not with the containers
+** used to hold those values.
+*/
+SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
+
+/*
+** CAPI3REF: Evaluate An SQL Statement
+** METHOD: sqlite3_stmt
+**
+** After a [prepared statement] has been prepared using any of
+** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
+** or [sqlite3_prepare16_v3()] or one of the legacy
+** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
+** must be called one or more times to evaluate the statement.
+**
+** The details of the behavior of the sqlite3_step() interface depend
+** on whether the statement was prepared using the newer "vX" interfaces
+** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
+** [sqlite3_prepare16_v2()] or the older legacy
+** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
+** new "vX" interface is recommended for new applications but the legacy
+** interface will continue to be supported.
+**
+** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
+** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
+** ^With the "v2" interface, any of the other [result codes] or
+** [extended result codes] might be returned as well.
+**
+** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
+** database locks it needs to do its job.  ^If the statement is a [COMMIT]
+** or occurs outside of an explicit transaction, then you can retry the
+** statement.  If the statement is not a [COMMIT] and occurs within an
+** explicit transaction then you should rollback the transaction before
+** continuing.
+**
+** ^[SQLITE_DONE] means that the statement has finished executing
+** successfully.  sqlite3_step() should not be called again on this virtual
+** machine without first calling [sqlite3_reset()] to reset the virtual
+** machine back to its initial state.
+**
+** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
+** is returned each time a new row of data is ready for processing by the
+** caller. The values may be accessed using the [column access functions].
+** sqlite3_step() is called again to retrieve the next row of data.
+**
+** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
+** violation) has occurred.  sqlite3_step() should not be called again on
+** the VM. More information may be found by calling [sqlite3_errmsg()].
+** ^With the legacy interface, a more specific error code (for example,
+** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
+** can be obtained by calling [sqlite3_reset()] on the
+** [prepared statement].  ^In the "v2" interface,
+** the more specific error code is returned directly by sqlite3_step().
+**
+** [SQLITE_MISUSE] means that the this routine was called inappropriately.
+** Perhaps it was called on a [prepared statement] that has
+** already been [sqlite3_finalize | finalized] or on one that had
+** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
+** be the case that the same database connection is being used by two or
+** more threads at the same moment in time.
+**
+** For all versions of SQLite up to and including 3.6.23.1, a call to
+** [sqlite3_reset()] was required after sqlite3_step() returned anything
+** other than [SQLITE_ROW] before any subsequent invocation of
+** sqlite3_step().  Failure to reset the prepared statement using
+** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
+** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
+** sqlite3_step() began
+** calling [sqlite3_reset()] automatically in this circumstance rather
+** than returning [SQLITE_MISUSE].  This is not considered a compatibility
+** break because any application that ever receives an SQLITE_MISUSE error
+** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
+** can be used to restore the legacy behavior.
+**
+** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
+** API always returns a generic error code, [SQLITE_ERROR], following any
+** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
+** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
+** specific [error codes] that better describes the error.
+** We admit that this is a goofy design.  The problem has been fixed
+** with the "v2" interface.  If you prepare all of your SQL statements
+** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
+** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
+** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
+** then the more specific [error codes] are returned directly
+** by sqlite3_step().  The use of the "vX" interfaces is recommended.
+*/
+SQLITE_API int sqlite3_step(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number of columns in a result set
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_data_count(P) interface returns the number of columns in the
+** current row of the result set of [prepared statement] P.
+** ^If prepared statement P does not have results ready to return
+** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
+** interfaces) then sqlite3_data_count(P) returns 0.
+** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
+** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
+** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
+** will return non-zero if previous call to [sqlite3_step](P) returned
+** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
+** where it always returns zero since each step of that multi-step
+** pragma returns 0 columns of data.
+**
+** See also: [sqlite3_column_count()]
+*/
+SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Fundamental Datatypes
+** KEYWORDS: SQLITE_TEXT
+**
+** ^(Every value in SQLite has one of five fundamental datatypes:
+**
+** <ul>
+** <li> 64-bit signed integer
+** <li> 64-bit IEEE floating point number
+** <li> string
+** <li> BLOB
+** <li> NULL
+** </ul>)^
+**
+** These constants are codes for each of those types.
+**
+** Note that the SQLITE_TEXT constant was also used in SQLite version 2
+** for a completely different meaning.  Software that links against both
+** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
+** SQLITE_TEXT.
+*/
+#define SQLITE_INTEGER  1
+#define SQLITE_FLOAT    2
+#define SQLITE_BLOB     4
+#define SQLITE_NULL     5
+#ifdef SQLITE_TEXT
+# undef SQLITE_TEXT
+#else
+# define SQLITE_TEXT     3
+#endif
+#define SQLITE3_TEXT     3
+
+/*
+** CAPI3REF: Result Values From A Query
+** KEYWORDS: {column access functions}
+** METHOD: sqlite3_stmt
+**
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result
+** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result
+** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result
+** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result
+** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result
+** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result
+** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an
+** [sqlite3_value|unprotected sqlite3_value] object.
+** <tr><td> <td> <td> 
+** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT result in bytes
+** <tr><td><b>sqlite3_column_bytes16  </b>
+** <td>→  <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_column_type</b><td>→<td>Default
+** datatype of the result
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
+** ^These routines return information about a single column of the current
+** result row of a query.  ^In every case the first argument is a pointer
+** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
+** that was returned from [sqlite3_prepare_v2()] or one of its variants)
+** and the second argument is the index of the column for which information
+** should be returned. ^The leftmost column of the result set has the index 0.
+** ^The number of columns in the result can be determined using
+** [sqlite3_column_count()].
+**
+** If the SQL statement does not currently point to a valid row, or if the
+** column index is out of range, the result is undefined.
+** These routines may only be called when the most recent call to
+** [sqlite3_step()] has returned [SQLITE_ROW] and neither
+** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
+** If any of these routines are called after [sqlite3_reset()] or
+** [sqlite3_finalize()] or after [sqlite3_step()] has returned
+** something other than [SQLITE_ROW], the results are undefined.
+** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
+** are called from a different thread while any of these routines
+** are pending, then the results are undefined.
+**
+** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
+** each return the value of a result column in a specific data format.  If
+** the result column is not initially in the requested format (for example,
+** if the query returns an integer but the sqlite3_column_text() interface
+** is used to extract the value) then an automatic type conversion is performed.
+**
+** ^The sqlite3_column_type() routine returns the
+** [SQLITE_INTEGER | datatype code] for the initial data type
+** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
+** The return value of sqlite3_column_type() can be used to decide which
+** of the first six interface should be used to extract the column value.
+** The value returned by sqlite3_column_type() is only meaningful if no
+** automatic type conversions have occurred for the value in question.
+** After a type conversion, the result of calling sqlite3_column_type()
+** is undefined, though harmless.  Future
+** versions of SQLite may change the behavior of sqlite3_column_type()
+** following a type conversion.
+**
+** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
+** or sqlite3_column_bytes16() interfaces can be used to determine the size
+** of that BLOB or string.
+**
+** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
+** the string to UTF-8 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
+**
+** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
+** the string to UTF-16 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes16() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
+**
+** ^The values returned by [sqlite3_column_bytes()] and
+** [sqlite3_column_bytes16()] do not include the zero terminators at the end
+** of the string.  ^For clarity: the values returned by
+** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
+** bytes in the string, not the number of characters.
+**
+** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
+** even empty strings, are always zero-terminated.  ^The return
+** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
+**
+** ^Strings returned by sqlite3_column_text16() always have the endianness
+** which is native to the platform, regardless of the text encoding set
+** for the database.
+**
+** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
+** [unprotected sqlite3_value] object.  In a multithreaded environment,
+** an unprotected sqlite3_value object may only be used safely with
+** [sqlite3_bind_value()] and [sqlite3_result_value()].
+** If the [unprotected sqlite3_value] object returned by
+** [sqlite3_column_value()] is used in any other way, including calls
+** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
+** or [sqlite3_value_bytes()], the behavior is not threadsafe.
+** Hence, the sqlite3_column_value() interface
+** is normally only useful within the implementation of
+** [application-defined SQL functions] or [virtual tables], not within
+** top-level application code.
+**
+** These routines may attempt to convert the datatype of the result.
+** ^For example, if the internal representation is FLOAT and a text result
+** is requested, [sqlite3_snprintf()] is used internally to perform the
+** conversion automatically.  ^(The following table details the conversions
+** that are applied:
+**
+** <blockquote>
+** <table border="1">
+** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
+**
+** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
+** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
+** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
+** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
+** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
+** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
+** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
+** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
+** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
+** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
+** <tr><td>  TEXT    <td>   BLOB    <td> No change
+** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
+** <tr><td>  BLOB    <td>   TEXT    <td> [CAST] to TEXT, ensure zero terminator
+** </table>
+** </blockquote>)^
+**
+** Note that when type conversions occur, pointers returned by prior
+** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
+** sqlite3_column_text16() may be invalidated.
+** Type conversions and pointer invalidations might occur
+** in the following cases:
+**
+** <ul>
+** <li> The initial content is a BLOB and sqlite3_column_text() or
+**      sqlite3_column_text16() is called.  A zero-terminator might
+**      need to be added to the string.</li>
+** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
+**      sqlite3_column_text16() is called.  The content must be converted
+**      to UTF-16.</li>
+** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
+**      sqlite3_column_text() is called.  The content must be converted
+**      to UTF-8.</li>
+** </ul>
+**
+** ^Conversions between UTF-16be and UTF-16le are always done in place and do
+** not invalidate a prior pointer, though of course the content of the buffer
+** that the prior pointer references will have been modified.  Other kinds
+** of conversion are done in place when it is possible, but sometimes they
+** are not possible and in those cases prior pointers are invalidated.
+**
+** The safest policy is to invoke these routines
+** in one of the following ways:
+**
+** <ul>
+**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
+** </ul>
+**
+** In other words, you should call sqlite3_column_text(),
+** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
+** into the desired format, then invoke sqlite3_column_bytes() or
+** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
+** to sqlite3_column_text() or sqlite3_column_blob() with calls to
+** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
+** with calls to sqlite3_column_bytes().
+**
+** ^The pointers returned are valid until a type conversion occurs as
+** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
+** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
+** and BLOBs is freed automatically.  Do not pass the pointers returned
+** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
+** [sqlite3_free()].
+**
+** As long as the input parameters are correct, these routines will only
+** fail if an out-of-memory error occurs during a format conversion.
+** Only the following subset of interfaces are subject to out-of-memory
+** errors:
+**
+** <ul>
+** <li> sqlite3_column_blob()
+** <li> sqlite3_column_text()
+** <li> sqlite3_column_text16()
+** <li> sqlite3_column_bytes()
+** <li> sqlite3_column_bytes16()
+** </ul>
+**
+** If an out-of-memory error occurs, then the return value from these
+** routines is the same as if the column had contained an SQL NULL value.
+** Valid SQL NULL returns can be distinguished from out-of-memory errors
+** by invoking the [sqlite3_errcode()] immediately after the suspect
+** return value is obtained and before any
+** other SQLite interface is called on the same [database connection].
+*/
+SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
+SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
+SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
+SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
+
+/*
+** CAPI3REF: Destroy A Prepared Statement Object
+** DESTRUCTOR: sqlite3_stmt
+**
+** ^The sqlite3_finalize() function is called to delete a [prepared statement].
+** ^If the most recent evaluation of the statement encountered no errors
+** or if the statement is never been evaluated, then sqlite3_finalize() returns
+** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
+** sqlite3_finalize(S) returns the appropriate [error code] or
+** [extended error code].
+**
+** ^The sqlite3_finalize(S) routine can be called at any point during
+** the life cycle of [prepared statement] S:
+** before statement S is ever evaluated, after
+** one or more calls to [sqlite3_reset()], or after any call
+** to [sqlite3_step()] regardless of whether or not the statement has
+** completed execution.
+**
+** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
+**
+** The application must finalize every [prepared statement] in order to avoid
+** resource leaks.  It is a grievous error for the application to try to use
+** a prepared statement after it has been finalized.  Any use of a prepared
+** statement after it has been finalized can result in undefined and
+** undesirable behavior such as segfaults and heap corruption.
+*/
+SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Reset A Prepared Statement Object
+** METHOD: sqlite3_stmt
+**
+** The sqlite3_reset() function is called to reset a [prepared statement]
+** object back to its initial state, ready to be re-executed.
+** ^Any SQL statement variables that had values bound to them using
+** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
+** Use [sqlite3_clear_bindings()] to reset the bindings.
+**
+** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
+** back to the beginning of its program.
+**
+** ^The return code from [sqlite3_reset(S)] indicates whether or not
+** the previous evaluation of prepared statement S completed successfully.
+** ^If [sqlite3_step(S)] has never before been called on S or if
+** [sqlite3_step(S)] has not been called since the previous call
+** to [sqlite3_reset(S)], then [sqlite3_reset(S)] will return
+** [SQLITE_OK].
+**
+** ^If the most recent call to [sqlite3_step(S)] for the
+** [prepared statement] S indicated an error, then
+** [sqlite3_reset(S)] returns an appropriate [error code].
+** ^The [sqlite3_reset(S)] interface might also return an [error code]
+** if there were no prior errors but the process of resetting
+** the prepared statement caused a new error. ^For example, if an
+** [INSERT] statement with a [RETURNING] clause is only stepped one time,
+** that one call to [sqlite3_step(S)] might return SQLITE_ROW but
+** the overall statement might still fail and the [sqlite3_reset(S)] call
+** might return SQLITE_BUSY if locking constraints prevent the
+** database change from committing.  Therefore, it is important that
+** applications check the return code from [sqlite3_reset(S)] even if
+** no prior call to [sqlite3_step(S)] indicated a problem.
+**
+** ^The [sqlite3_reset(S)] interface does not change the values
+** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
+*/
+SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
+
+
+/*
+** CAPI3REF: Create Or Redefine SQL Functions
+** KEYWORDS: {function creation routines}
+** METHOD: sqlite3
+**
+** ^These functions (collectively known as "function creation routines")
+** are used to add SQL functions or aggregates or to redefine the behavior
+** of existing SQL functions or aggregates. The only differences between
+** the three "sqlite3_create_function*" routines are the text encoding
+** expected for the second parameter (the name of the function being
+** created) and the presence or absence of a destructor callback for
+** the application data pointer. Function sqlite3_create_window_function()
+** is similar, but allows the user to supply the extra callback functions
+** needed by [aggregate window functions].
+**
+** ^The first parameter is the [database connection] to which the SQL
+** function is to be added.  ^If an application uses more than one database
+** connection then application-defined SQL functions must be added
+** to each database connection separately.
+**
+** ^The second parameter is the name of the SQL function to be created or
+** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
+** representation, exclusive of the zero-terminator.  ^Note that the name
+** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
+** ^Any attempt to create a function with a longer name
+** will result in [SQLITE_MISUSE] being returned.
+**
+** ^The third parameter (nArg)
+** is the number of arguments that the SQL function or
+** aggregate takes. ^If this parameter is -1, then the SQL function or
+** aggregate may take any number of arguments between 0 and the limit
+** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
+** parameter is less than -1 or greater than 127 then the behavior is
+** undefined.
+**
+** ^The fourth parameter, eTextRep, specifies what
+** [SQLITE_UTF8 | text encoding] this SQL function prefers for
+** its parameters.  The application should set this parameter to
+** [SQLITE_UTF16LE] if the function implementation invokes
+** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
+** implementation invokes [sqlite3_value_text16be()] on an input, or
+** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
+** otherwise.  ^The same SQL function may be registered multiple times using
+** different preferred text encodings, with different implementations for
+** each encoding.
+** ^When multiple implementations of the same function are available, SQLite
+** will pick the one that involves the least amount of data conversion.
+**
+** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
+** to signal that the function will always return the same result given
+** the same inputs within a single SQL statement.  Most SQL functions are
+** deterministic.  The built-in [random()] SQL function is an example of a
+** function that is not deterministic.  The SQLite query planner is able to
+** perform additional optimizations on deterministic functions, so use
+** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
+**
+** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
+** flag, which if present prevents the function from being invoked from
+** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
+** index expressions, or the WHERE clause of partial indexes.
+**
+** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
+** all application-defined SQL functions that do not need to be
+** used inside of triggers, view, CHECK constraints, or other elements of
+** the database schema.  This flags is especially recommended for SQL
+** functions that have side effects or reveal internal application state.
+** Without this flag, an attacker might be able to modify the schema of
+** a database file to include invocations of the function with parameters
+** chosen by the attacker, which the application will then execute when
+** the database file is opened and read.
+**
+** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
+** function can gain access to this pointer using [sqlite3_user_data()].)^
+**
+** ^The sixth, seventh and eighth parameters passed to the three
+** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
+** pointers to C-language functions that implement the SQL function or
+** aggregate. ^A scalar SQL function requires an implementation of the xFunc
+** callback only; NULL pointers must be passed as the xStep and xFinal
+** parameters. ^An aggregate SQL function requires an implementation of xStep
+** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
+** SQL function or aggregate, pass NULL pointers for all three function
+** callbacks.
+**
+** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
+** and xInverse) passed to sqlite3_create_window_function are pointers to
+** C-language callbacks that implement the new function. xStep and xFinal
+** must both be non-NULL. xValue and xInverse may either both be NULL, in
+** which case a regular aggregate function is created, or must both be
+** non-NULL, in which case the new function may be used as either an aggregate
+** or aggregate window function. More details regarding the implementation
+** of aggregate window functions are
+** [user-defined window functions|available here].
+**
+** ^(If the final parameter to sqlite3_create_function_v2() or
+** sqlite3_create_window_function() is not NULL, then it is destructor for
+** the application data pointer. The destructor is invoked when the function
+** is deleted, either by being overloaded or when the database connection
+** closes.)^ ^The destructor is also invoked if the call to
+** sqlite3_create_function_v2() fails.  ^When the destructor callback is
+** invoked, it is passed a single argument which is a copy of the application
+** data pointer which was the fifth parameter to sqlite3_create_function_v2().
+**
+** ^It is permitted to register multiple implementations of the same
+** functions with the same name but with either differing numbers of
+** arguments or differing preferred text encodings.  ^SQLite will use
+** the implementation that most closely matches the way in which the
+** SQL function is used.  ^A function implementation with a non-negative
+** nArg parameter is a better match than a function implementation with
+** a negative nArg.  ^A function where the preferred text encoding
+** matches the database encoding is a better
+** match than a function where the encoding is different.
+** ^A function where the encoding difference is between UTF16le and UTF16be
+** is a closer match than a function where the encoding difference is
+** between UTF8 and UTF16.
+**
+** ^Built-in functions may be overloaded by new application-defined functions.
+**
+** ^An application-defined function is permitted to call other
+** SQLite interfaces.  However, such calls must not
+** close the database connection nor finalize or reset the prepared
+** statement in which the function is running.
+*/
+SQLITE_API int sqlite3_create_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+SQLITE_API int sqlite3_create_function16(
+  sqlite3 *db,
+  const void *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+SQLITE_API int sqlite3_create_function_v2(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void(*xDestroy)(void*)
+);
+SQLITE_API int sqlite3_create_window_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
+  void(*xDestroy)(void*)
+);
+
+/*
+** CAPI3REF: Text Encodings
+**
+** These constant define integer codes that represent the various
+** text encodings supported by SQLite.
+*/
+#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
+#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
+#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
+#define SQLITE_UTF16          4    /* Use native byte order */
+#define SQLITE_ANY            5    /* Deprecated */
+#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
+
+/*
+** CAPI3REF: Function Flags
+**
+** These constants may be ORed together with the
+** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
+** to [sqlite3_create_function()], [sqlite3_create_function16()], or
+** [sqlite3_create_function_v2()].
+**
+** <dl>
+** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
+** The SQLITE_DETERMINISTIC flag means that the new function always gives
+** the same output when the input parameters are the same.
+** The [abs|abs() function] is deterministic, for example, but
+** [randomblob|randomblob()] is not.  Functions must
+** be deterministic in order to be used in certain contexts such as
+** with the WHERE clause of [partial indexes] or in [generated columns].
+** SQLite might also optimize deterministic functions by factoring them
+** out of inner loops.
+** </dd>
+**
+** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
+** The SQLITE_DIRECTONLY flag means that the function may only be invoked
+** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
+** schema structures such as [CHECK constraints], [DEFAULT clauses],
+** [expression indexes], [partial indexes], or [generated columns].
+** <p>
+** The SQLITE_DIRECTONLY flag is recommended for any
+** [application-defined SQL function]
+** that has side-effects or that could potentially leak sensitive information.
+** This will prevent attacks in which an application is tricked
+** into using a database file that has had its schema surreptitiously
+** modified to invoke the application-defined function in ways that are
+** harmful.
+** <p>
+** Some people say it is good practice to set SQLITE_DIRECTONLY on all
+** [application-defined SQL functions], regardless of whether or not they
+** are security sensitive, as doing so prevents those functions from being used
+** inside of the database schema, and thus ensures that the database
+** can be inspected and modified using generic tools (such as the [CLI])
+** that do not have access to the application-defined functions.
+** </dd>
+**
+** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
+** The SQLITE_INNOCUOUS flag means that the function is unlikely
+** to cause problems even if misused.  An innocuous function should have
+** no side effects and should not depend on any values other than its
+** input parameters. The [abs|abs() function] is an example of an
+** innocuous function.
+** The [load_extension() SQL function] is not innocuous because of its
+** side effects.
+** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
+** exactly the same.  The [random|random() function] is an example of a
+** function that is innocuous but not deterministic.
+** <p>Some heightened security settings
+** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
+** disable the use of SQL functions inside views and triggers and in
+** schema structures such as [CHECK constraints], [DEFAULT clauses],
+** [expression indexes], [partial indexes], and [generated columns] unless
+** the function is tagged with SQLITE_INNOCUOUS.  Most built-in functions
+** are innocuous.  Developers are advised to avoid using the
+** SQLITE_INNOCUOUS flag for application-defined functions unless the
+** function has been carefully audited and found to be free of potentially
+** security-adverse side-effects and information-leaks.
+** </dd>
+**
+** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
+** The SQLITE_SUBTYPE flag indicates to SQLite that a function might call
+** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
+** This flag instructs SQLite to omit some corner-case optimizations that
+** might disrupt the operation of the [sqlite3_value_subtype()] function,
+** causing it to return zero rather than the correct subtype().
+** All SQL functions that invoke [sqlite3_value_subtype()] should have this
+** property.  If the SQLITE_SUBTYPE property is omitted, then the return
+** value from [sqlite3_value_subtype()] might sometimes be zero even though
+** a non-zero subtype was specified by the function argument expression.
+**
+** [[SQLITE_RESULT_SUBTYPE]] <dt>SQLITE_RESULT_SUBTYPE</dt><dd>
+** The SQLITE_RESULT_SUBTYPE flag indicates to SQLite that a function might call
+** [sqlite3_result_subtype()] to cause a sub-type to be associated with its
+** result.
+** Every function that invokes [sqlite3_result_subtype()] should have this
+** property.  If it does not, then the call to [sqlite3_result_subtype()]
+** might become a no-op if the function is used as term in an
+** [expression index].  On the other hand, SQL functions that never invoke
+** [sqlite3_result_subtype()] should avoid setting this property, as the
+** purpose of this property is to disable certain optimizations that are
+** incompatible with subtypes.
+**
+** [[SQLITE_SELFORDER1]] <dt>SQLITE_SELFORDER1</dt><dd>
+** The SQLITE_SELFORDER1 flag indicates that the function is an aggregate
+** that internally orders the values provided to the first argument.  The
+** ordered-set aggregate SQL notation with a single ORDER BY term can be
+** used to invoke this function.  If the ordered-set aggregate notation is
+** used on a function that lacks this flag, then an error is raised. Note
+** that the ordered-set aggregate syntax is only available if SQLite is
+** built using the -DSQLITE_ENABLE_ORDERED_SET_AGGREGATES compile-time option.
+** </dd>
+** </dl>
+*/
+#define SQLITE_DETERMINISTIC    0x000000800
+#define SQLITE_DIRECTONLY       0x000080000
+#define SQLITE_SUBTYPE          0x000100000
+#define SQLITE_INNOCUOUS        0x000200000
+#define SQLITE_RESULT_SUBTYPE   0x001000000
+#define SQLITE_SELFORDER1       0x002000000
+
+/*
+** CAPI3REF: Deprecated Functions
+** DEPRECATED
+**
+** These functions are [deprecated].  In order to maintain
+** backwards compatibility with older code, these functions continue
+** to be supported.  However, new applications should avoid
+** the use of these functions.  To encourage programmers to avoid
+** these functions, we will not explain what they do.
+*/
+#ifndef SQLITE_OMIT_DEPRECATED
+SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
+SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
+                      void*,sqlite3_int64);
+#endif
+
+/*
+** CAPI3REF: Obtaining SQL Values
+** METHOD: sqlite3_value
+**
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value
+** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value
+** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value
+** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value
+** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value
+** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value
+** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in
+** the native byteorder
+** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value
+** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value
+** <tr><td> <td> <td> 
+** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT in bytes
+** <tr><td><b>sqlite3_value_bytes16  </b>
+** <td>→  <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_value_type</b><td>→<td>Default
+** datatype of the value
+** <tr><td><b>sqlite3_value_numeric_type  </b>
+** <td>→  <td>Best numeric datatype of the value
+** <tr><td><b>sqlite3_value_nochange  </b>
+** <td>→  <td>True if the column is unchanged in an UPDATE
+** against a virtual table.
+** <tr><td><b>sqlite3_value_frombind  </b>
+** <td>→  <td>True if value originated from a [bound parameter]
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
+** These routines extract type, size, and content information from
+** [protected sqlite3_value] objects.  Protected sqlite3_value objects
+** are used to pass parameter information into the functions that
+** implement [application-defined SQL functions] and [virtual tables].
+**
+** These routines work only with [protected sqlite3_value] objects.
+** Any attempt to use these routines on an [unprotected sqlite3_value]
+** is not threadsafe.
+**
+** ^These routines work just like the corresponding [column access functions]
+** except that these routines take a single [protected sqlite3_value] object
+** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
+**
+** ^The sqlite3_value_text16() interface extracts a UTF-16 string
+** in the native byte-order of the host machine.  ^The
+** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
+** extract UTF-16 strings as big-endian and little-endian respectively.
+**
+** ^If [sqlite3_value] object V was initialized
+** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
+** and if X and Y are strings that compare equal according to strcmp(X,Y),
+** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
+** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
+** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
+**
+** ^(The sqlite3_value_type(V) interface returns the
+** [SQLITE_INTEGER | datatype code] for the initial datatype of the
+** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
+** Other interfaces might change the datatype for an sqlite3_value object.
+** For example, if the datatype is initially SQLITE_INTEGER and
+** sqlite3_value_text(V) is called to extract a text value for that
+** integer, then subsequent calls to sqlite3_value_type(V) might return
+** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
+** occurs is undefined and may change from one release of SQLite to the next.
+**
+** ^(The sqlite3_value_numeric_type() interface attempts to apply
+** numeric affinity to the value.  This means that an attempt is
+** made to convert the value to an integer or floating point.  If
+** such a conversion is possible without loss of information (in other
+** words, if the value is a string that looks like a number)
+** then the conversion is performed.  Otherwise no conversion occurs.
+** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
+**
+** ^Within the [xUpdate] method of a [virtual table], the
+** sqlite3_value_nochange(X) interface returns true if and only if
+** the column corresponding to X is unchanged by the UPDATE operation
+** that the xUpdate method call was invoked to implement and if
+** and the prior [xColumn] method call that was invoked to extracted
+** the value for that column returned without setting a result (probably
+** because it queried [sqlite3_vtab_nochange()] and found that the column
+** was unchanging).  ^Within an [xUpdate] method, any value for which
+** sqlite3_value_nochange(X) is true will in all other respects appear
+** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
+** than within an [xUpdate] method call for an UPDATE statement, then
+** the return value is arbitrary and meaningless.
+**
+** ^The sqlite3_value_frombind(X) interface returns non-zero if the
+** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
+** interfaces.  ^If X comes from an SQL literal value, or a table column,
+** or an expression, then sqlite3_value_frombind(X) returns zero.
+**
+** Please pay particular attention to the fact that the pointer returned
+** from [sqlite3_value_blob()], [sqlite3_value_text()], or
+** [sqlite3_value_text16()] can be invalidated by a subsequent call to
+** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
+** or [sqlite3_value_text16()].
+**
+** These routines must be called from the same thread as
+** the SQL function that supplied the [sqlite3_value*] parameters.
+**
+** As long as the input parameter is correct, these routines can only
+** fail if an out-of-memory error occurs during a format conversion.
+** Only the following subset of interfaces are subject to out-of-memory
+** errors:
+**
+** <ul>
+** <li> sqlite3_value_blob()
+** <li> sqlite3_value_text()
+** <li> sqlite3_value_text16()
+** <li> sqlite3_value_text16le()
+** <li> sqlite3_value_text16be()
+** <li> sqlite3_value_bytes()
+** <li> sqlite3_value_bytes16()
+** </ul>
+**
+** If an out-of-memory error occurs, then the return value from these
+** routines is the same as if the column had contained an SQL NULL value.
+** Valid SQL NULL returns can be distinguished from out-of-memory errors
+** by invoking the [sqlite3_errcode()] immediately after the suspect
+** return value is obtained and before any
+** other SQLite interface is called on the same [database connection].
+*/
+SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
+SQLITE_API double sqlite3_value_double(sqlite3_value*);
+SQLITE_API int sqlite3_value_int(sqlite3_value*);
+SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
+SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
+SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
+SQLITE_API int sqlite3_value_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
+SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
+
+/*
+** CAPI3REF: Report the internal text encoding state of an sqlite3_value object
+** METHOD: sqlite3_value
+**
+** ^(The sqlite3_value_encoding(X) interface returns one of [SQLITE_UTF8],
+** [SQLITE_UTF16BE], or [SQLITE_UTF16LE] according to the current text encoding
+** of the value X, assuming that X has type TEXT.)^  If sqlite3_value_type(X)
+** returns something other than SQLITE_TEXT, then the return value from
+** sqlite3_value_encoding(X) is meaningless.  ^Calls to
+** [sqlite3_value_text(X)], [sqlite3_value_text16(X)], [sqlite3_value_text16be(X)],
+** [sqlite3_value_text16le(X)], [sqlite3_value_bytes(X)], or
+** [sqlite3_value_bytes16(X)] might change the encoding of the value X and
+** thus change the return from subsequent calls to sqlite3_value_encoding(X).
+**
+** This routine is intended for used by applications that test and validate
+** the SQLite implementation.  This routine is inquiring about the opaque
+** internal state of an [sqlite3_value] object.  Ordinary applications should
+** not need to know what the internal state of an sqlite3_value object is and
+** hence should not need to use this interface.
+*/
+SQLITE_API int sqlite3_value_encoding(sqlite3_value*);
+
+/*
+** CAPI3REF: Finding The Subtype Of SQL Values
+** METHOD: sqlite3_value
+**
+** The sqlite3_value_subtype(V) function returns the subtype for
+** an [application-defined SQL function] argument V.  The subtype
+** information can be used to pass a limited amount of context from
+** one SQL function to another.  Use the [sqlite3_result_subtype()]
+** routine to set the subtype for the return value of an SQL function.
+**
+** Every [application-defined SQL function] that invokes this interface
+** should include the [SQLITE_SUBTYPE] property in the text
+** encoding argument when the function is [sqlite3_create_function|registered].
+** If the [SQLITE_SUBTYPE] property is omitted, then sqlite3_value_subtype()
+** might return zero instead of the upstream subtype in some corner cases.
+*/
+SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
+
+/*
+** CAPI3REF: Copy And Free SQL Values
+** METHOD: sqlite3_value
+**
+** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
+** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
+** is a [protected sqlite3_value] object even if the input is not.
+** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
+** memory allocation fails. ^If V is a [pointer value], then the result
+** of sqlite3_value_dup(V) is a NULL value.
+**
+** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
+** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
+** then sqlite3_value_free(V) is a harmless no-op.
+*/
+SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
+SQLITE_API void sqlite3_value_free(sqlite3_value*);
+
+/*
+** CAPI3REF: Obtain Aggregate Function Context
+** METHOD: sqlite3_context
+**
+** Implementations of aggregate SQL functions use this
+** routine to allocate memory for storing their state.
+**
+** ^The first time the sqlite3_aggregate_context(C,N) routine is called
+** for a particular aggregate function, SQLite allocates
+** N bytes of memory, zeroes out that memory, and returns a pointer
+** to the new memory. ^On second and subsequent calls to
+** sqlite3_aggregate_context() for the same aggregate function instance,
+** the same buffer is returned.  Sqlite3_aggregate_context() is normally
+** called once for each invocation of the xStep callback and then one
+** last time when the xFinal callback is invoked.  ^(When no rows match
+** an aggregate query, the xStep() callback of the aggregate function
+** implementation is never called and xFinal() is called exactly once.
+** In those cases, sqlite3_aggregate_context() might be called for the
+** first time from within xFinal().)^
+**
+** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
+** when first called if N is less than or equal to zero or if a memory
+** allocation error occurs.
+**
+** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
+** determined by the N parameter on first successful call.  Changing the
+** value of N in any subsequent call to sqlite3_aggregate_context() within
+** the same aggregate function instance will not resize the memory
+** allocation.)^  Within the xFinal callback, it is customary to set
+** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
+** pointless memory allocations occur.
+**
+** ^SQLite automatically frees the memory allocated by
+** sqlite3_aggregate_context() when the aggregate query concludes.
+**
+** The first parameter must be a copy of the
+** [sqlite3_context | SQL function context] that is the first parameter
+** to the xStep or xFinal callback routine that implements the aggregate
+** function.
+**
+** This routine must be called from the same thread in which
+** the aggregate SQL function is running.
+*/
+SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
+
+/*
+** CAPI3REF: User Data For Functions
+** METHOD: sqlite3_context
+**
+** ^The sqlite3_user_data() interface returns a copy of
+** the pointer that was the pUserData parameter (the 5th parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+**
+** This routine must be called from the same thread in which
+** the application-defined function is running.
+*/
+SQLITE_API void *sqlite3_user_data(sqlite3_context*);
+
+/*
+** CAPI3REF: Database Connection For Functions
+** METHOD: sqlite3_context
+**
+** ^The sqlite3_context_db_handle() interface returns a copy of
+** the pointer to the [database connection] (the 1st parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+*/
+SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
+
+/*
+** CAPI3REF: Function Auxiliary Data
+** METHOD: sqlite3_context
+**
+** These functions may be used by (non-aggregate) SQL functions to
+** associate auxiliary data with argument values. If the same argument
+** value is passed to multiple invocations of the same SQL function during
+** query execution, under some circumstances the associated auxiliary data
+** might be preserved.  An example of where this might be useful is in a
+** regular-expression matching function. The compiled version of the regular
+** expression can be stored as auxiliary data associated with the pattern string.
+** Then as long as the pattern string remains the same,
+** the compiled regular expression can be reused on multiple
+** invocations of the same function.
+**
+** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the auxiliary data
+** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
+** value to the application-defined function.  ^N is zero for the left-most
+** function argument.  ^If there is no auxiliary data
+** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
+** returns a NULL pointer.
+**
+** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as auxiliary data for the
+** N-th argument of the application-defined function.  ^Subsequent
+** calls to sqlite3_get_auxdata(C,N) return P from the most recent
+** sqlite3_set_auxdata(C,N,P,X) call if the auxiliary data is still valid or
+** NULL if the auxiliary data has been discarded.
+** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
+** SQLite will invoke the destructor function X with parameter P exactly
+** once, when the auxiliary data is discarded.
+** SQLite is free to discard the auxiliary data at any time, including: <ul>
+** <li> ^(when the corresponding function parameter changes)^, or
+** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
+**      SQL statement)^, or
+** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
+**       parameter)^, or
+** <li> ^(during the original sqlite3_set_auxdata() call when a memory
+**      allocation error occurs.)^
+** <li> ^(during the original sqlite3_set_auxdata() call if the function
+**      is evaluated during query planning instead of during query execution,
+**      as sometimes happens with [SQLITE_ENABLE_STAT4].)^ </ul>
+**
+** Note the last two bullets in particular.  The destructor X in
+** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
+** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
+** should be called near the end of the function implementation and the
+** function implementation should not make any use of P after
+** sqlite3_set_auxdata() has been called.  Furthermore, a call to
+** sqlite3_get_auxdata() that occurs immediately after a corresponding call
+** to sqlite3_set_auxdata() might still return NULL if an out-of-memory
+** condition occurred during the sqlite3_set_auxdata() call or if the
+** function is being evaluated during query planning rather than during
+** query execution.
+**
+** ^(In practice, auxiliary data is preserved between function calls for
+** function parameters that are compile-time constants, including literal
+** values and [parameters] and expressions composed from the same.)^
+**
+** The value of the N parameter to these interfaces should be non-negative.
+** Future enhancements may make use of negative N values to define new
+** kinds of function caching behavior.
+**
+** These routines must be called from the same thread in which
+** the SQL function is running.
+**
+** See also: [sqlite3_get_clientdata()] and [sqlite3_set_clientdata()].
+*/
+SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
+SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
+
+/*
+** CAPI3REF: Database Connection Client Data
+** METHOD: sqlite3
+**
+** These functions are used to associate one or more named pointers
+** with a [database connection].
+** A call to sqlite3_set_clientdata(D,N,P,X) causes the pointer P
+** to be attached to [database connection] D using name N.  Subsequent
+** calls to sqlite3_get_clientdata(D,N) will return a copy of pointer P
+** or a NULL pointer if there were no prior calls to
+** sqlite3_set_clientdata() with the same values of D and N.
+** Names are compared using strcmp() and are thus case sensitive.
+**
+** If P and X are both non-NULL, then the destructor X is invoked with
+** argument P on the first of the following occurrences:
+** <ul>
+** <li> An out-of-memory error occurs during the call to
+**      sqlite3_set_clientdata() which attempts to register pointer P.
+** <li> A subsequent call to sqlite3_set_clientdata(D,N,P,X) is made
+**      with the same D and N parameters.
+** <li> The database connection closes.  SQLite does not make any guarantees
+**      about the order in which destructors are called, only that all
+**      destructors will be called exactly once at some point during the
+**      database connection closing process.
+** </ul>
+**
+** SQLite does not do anything with client data other than invoke
+** destructors on the client data at the appropriate time.  The intended
+** use for client data is to provide a mechanism for wrapper libraries
+** to store additional information about an SQLite database connection.
+**
+** There is no limit (other than available memory) on the number of different
+** client data pointers (with different names) that can be attached to a
+** single database connection.  However, the implementation is optimized
+** for the case of having only one or two different client data names.
+** Applications and wrapper libraries are discouraged from using more than
+** one client data name each.
+**
+** There is no way to enumerate the client data pointers
+** associated with a database connection.  The N parameter can be thought
+** of as a secret key such that only code that knows the secret key is able
+** to access the associated data.
+**
+** Security Warning:  These interfaces should not be exposed in scripting
+** languages or in other circumstances where it might be possible for an
+** an attacker to invoke them.  Any agent that can invoke these interfaces
+** can probably also take control of the process.
+**
+** Database connection client data is only available for SQLite
+** version 3.44.0 ([dateof:3.44.0]) and later.
+**
+** See also: [sqlite3_set_auxdata()] and [sqlite3_get_auxdata()].
+*/
+SQLITE_API void *sqlite3_get_clientdata(sqlite3*,const char*);
+SQLITE_API int sqlite3_set_clientdata(sqlite3*, const char*, void*, void(*)(void*));
+
+/*
+** CAPI3REF: Constants Defining Special Destructor Behavior
+**
+** These are special values for the destructor that is passed in as the
+** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
+** argument is SQLITE_STATIC, it means that the content pointer is constant
+** and will never change.  It does not need to be destroyed.  ^The
+** SQLITE_TRANSIENT value means that the content will likely change in
+** the near future and that SQLite should make its own private copy of
+** the content before returning.
+**
+** The typedef is necessary to work around problems in certain
+** C++ compilers.
+*/
+typedef void (*sqlite3_destructor_type)(void*);
+#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
+#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
+
+/*
+** CAPI3REF: Setting The Result Of An SQL Function
+** METHOD: sqlite3_context
+**
+** These routines are used by the xFunc or xFinal callbacks that
+** implement SQL functions and aggregates.  See
+** [sqlite3_create_function()] and [sqlite3_create_function16()]
+** for additional information.
+**
+** These functions work very much like the [parameter binding] family of
+** functions used to bind values to host parameters in prepared statements.
+** Refer to the [SQL parameter] documentation for additional information.
+**
+** ^The sqlite3_result_blob() interface sets the result from
+** an application-defined function to be the BLOB whose content is pointed
+** to by the second parameter and which is N bytes long where N is the
+** third parameter.
+**
+** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
+** interfaces set the result of the application-defined function to be
+** a BLOB containing all zero bytes and N bytes in size.
+**
+** ^The sqlite3_result_double() interface sets the result from
+** an application-defined function to be a floating point value specified
+** by its 2nd argument.
+**
+** ^The sqlite3_result_error() and sqlite3_result_error16() functions
+** cause the implemented SQL function to throw an exception.
+** ^SQLite uses the string pointed to by the
+** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
+** as the text of an error message.  ^SQLite interprets the error
+** message string from sqlite3_result_error() as UTF-8. ^SQLite
+** interprets the string from sqlite3_result_error16() as UTF-16 using
+** the same [byte-order determination rules] as [sqlite3_bind_text16()].
+** ^If the third parameter to sqlite3_result_error()
+** or sqlite3_result_error16() is negative then SQLite takes as the error
+** message all text up through the first zero character.
+** ^If the third parameter to sqlite3_result_error() or
+** sqlite3_result_error16() is non-negative then SQLite takes that many
+** bytes (not characters) from the 2nd parameter as the error message.
+** ^The sqlite3_result_error() and sqlite3_result_error16()
+** routines make a private copy of the error message text before
+** they return.  Hence, the calling function can deallocate or
+** modify the text after they return without harm.
+** ^The sqlite3_result_error_code() function changes the error code
+** returned by SQLite as a result of an error in a function.  ^By default,
+** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
+** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
+**
+** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
+** error indicating that a string or BLOB is too long to represent.
+**
+** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
+** error indicating that a memory allocation failed.
+**
+** ^The sqlite3_result_int() interface sets the return value
+** of the application-defined function to be the 32-bit signed integer
+** value given in the 2nd argument.
+** ^The sqlite3_result_int64() interface sets the return value
+** of the application-defined function to be the 64-bit signed integer
+** value given in the 2nd argument.
+**
+** ^The sqlite3_result_null() interface sets the return value
+** of the application-defined function to be NULL.
+**
+** ^The sqlite3_result_text(), sqlite3_result_text16(),
+** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
+** set the return value of the application-defined function to be
+** a text string which is represented as UTF-8, UTF-16 native byte order,
+** UTF-16 little endian, or UTF-16 big endian, respectively.
+** ^The sqlite3_result_text64() interface sets the return value of an
+** application-defined function to be a text string in an encoding
+** specified by the fifth (and last) parameter, which must be one
+** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
+** ^SQLite takes the text result from the application from
+** the 2nd parameter of the sqlite3_result_text* interfaces.
+** ^If the 3rd parameter to any of the sqlite3_result_text* interfaces
+** other than sqlite3_result_text64() is negative, then SQLite computes
+** the string length itself by searching the 2nd parameter for the first
+** zero character.
+** ^If the 3rd parameter to the sqlite3_result_text* interfaces
+** is non-negative, then as many bytes (not characters) of the text
+** pointed to by the 2nd parameter are taken as the application-defined
+** function result.  If the 3rd parameter is non-negative, then it
+** must be the byte offset into the string where the NUL terminator would
+** appear if the string where NUL terminated.  If any NUL characters occur
+** in the string at a byte offset that is less than the value of the 3rd
+** parameter, then the resulting string will contain embedded NULs and the
+** result of expressions operating on strings with embedded NULs is undefined.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
+** function as the destructor on the text or BLOB result when it has
+** finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
+** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
+** assumes that the text or BLOB result is in constant space and does not
+** copy the content of the parameter nor call a destructor on the content
+** when it has finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
+** then SQLite makes a copy of the result into space obtained
+** from [sqlite3_malloc()] before it returns.
+**
+** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
+** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
+** when the encoding is not UTF8, if the input UTF16 begins with a
+** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
+** string and the rest of the string is interpreted according to the
+** byte-order specified by the BOM.  ^The byte-order specified by
+** the BOM at the beginning of the text overrides the byte-order
+** specified by the interface procedure.  ^So, for example, if
+** sqlite3_result_text16le() is invoked with text that begins
+** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
+** first two bytes of input are skipped and the remaining input
+** is interpreted as UTF16BE text.
+**
+** ^For UTF16 input text to the sqlite3_result_text16(),
+** sqlite3_result_text16be(), sqlite3_result_text16le(), and
+** sqlite3_result_text64() routines, if the text contains invalid
+** UTF16 characters, the invalid characters might be converted
+** into the unicode replacement character, U+FFFD.
+**
+** ^The sqlite3_result_value() interface sets the result of
+** the application-defined function to be a copy of the
+** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
+** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
+** so that the [sqlite3_value] specified in the parameter may change or
+** be deallocated after sqlite3_result_value() returns without harm.
+** ^A [protected sqlite3_value] object may always be used where an
+** [unprotected sqlite3_value] object is required, so either
+** kind of [sqlite3_value] object can be used with this interface.
+**
+** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
+** SQL NULL value, just like [sqlite3_result_null(C)], except that it
+** also associates the host-language pointer P or type T with that
+** NULL value such that the pointer can be retrieved within an
+** [application-defined SQL function] using [sqlite3_value_pointer()].
+** ^If the D parameter is not NULL, then it is a pointer to a destructor
+** for the P parameter.  ^SQLite invokes D with P as its only argument
+** when SQLite is finished with P.  The T parameter should be a static
+** string and preferably a string literal. The sqlite3_result_pointer()
+** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
+**
+** If these routines are called from within the different thread
+** than the one containing the application-defined function that received
+** the [sqlite3_context] pointer, the results are undefined.
+*/
+SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
+                           sqlite3_uint64,void(*)(void*));
+SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
+SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
+SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
+SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
+SQLITE_API void sqlite3_result_null(sqlite3_context*);
+SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
+                           void(*)(void*), unsigned char encoding);
+SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
+SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
+SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
+SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
+
+
+/*
+** CAPI3REF: Setting The Subtype Of An SQL Function
+** METHOD: sqlite3_context
+**
+** The sqlite3_result_subtype(C,T) function causes the subtype of
+** the result from the [application-defined SQL function] with
+** [sqlite3_context] C to be the value T.  Only the lower 8 bits
+** of the subtype T are preserved in current versions of SQLite;
+** higher order bits are discarded.
+** The number of subtype bytes preserved by SQLite might increase
+** in future releases of SQLite.
+**
+** Every [application-defined SQL function] that invokes this interface
+** should include the [SQLITE_RESULT_SUBTYPE] property in its
+** text encoding argument when the SQL function is
+** [sqlite3_create_function|registered].  If the [SQLITE_RESULT_SUBTYPE]
+** property is omitted from the function that invokes sqlite3_result_subtype(),
+** then in some cases the sqlite3_result_subtype() might fail to set
+** the result subtype.
+**
+** If SQLite is compiled with -DSQLITE_STRICT_SUBTYPE=1, then any
+** SQL function that invokes the sqlite3_result_subtype() interface
+** and that does not have the SQLITE_RESULT_SUBTYPE property will raise
+** an error.  Future versions of SQLite might enable -DSQLITE_STRICT_SUBTYPE=1
+** by default.
+*/
+SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
+
+/*
+** CAPI3REF: Define New Collating Sequences
+** METHOD: sqlite3
+**
+** ^These functions add, remove, or modify a [collation] associated
+** with the [database connection] specified as the first argument.
+**
+** ^The name of the collation is a UTF-8 string
+** for sqlite3_create_collation() and sqlite3_create_collation_v2()
+** and a UTF-16 string in native byte order for sqlite3_create_collation16().
+** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
+** considered to be the same name.
+**
+** ^(The third argument (eTextRep) must be one of the constants:
+** <ul>
+** <li> [SQLITE_UTF8],
+** <li> [SQLITE_UTF16LE],
+** <li> [SQLITE_UTF16BE],
+** <li> [SQLITE_UTF16], or
+** <li> [SQLITE_UTF16_ALIGNED].
+** </ul>)^
+** ^The eTextRep argument determines the encoding of strings passed
+** to the collating function callback, xCompare.
+** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
+** force strings to be UTF16 with native byte order.
+** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
+** on an even byte address.
+**
+** ^The fourth argument, pArg, is an application data pointer that is passed
+** through as the first argument to the collating function callback.
+**
+** ^The fifth argument, xCompare, is a pointer to the collating function.
+** ^Multiple collating functions can be registered using the same name but
+** with different eTextRep parameters and SQLite will use whichever
+** function requires the least amount of data transformation.
+** ^If the xCompare argument is NULL then the collating function is
+** deleted.  ^When all collating functions having the same name are deleted,
+** that collation is no longer usable.
+**
+** ^The collating function callback is invoked with a copy of the pArg
+** application data pointer and with two strings in the encoding specified
+** by the eTextRep argument.  The two integer parameters to the collating
+** function callback are the length of the two strings, in bytes. The collating
+** function must return an integer that is negative, zero, or positive
+** if the first string is less than, equal to, or greater than the second,
+** respectively.  A collating function must always return the same answer
+** given the same inputs.  If two or more collating functions are registered
+** to the same collation name (using different eTextRep values) then all
+** must give an equivalent answer when invoked with equivalent strings.
+** The collating function must obey the following properties for all
+** strings A, B, and C:
+**
+** <ol>
+** <li> If A==B then B==A.
+** <li> If A==B and B==C then A==C.
+** <li> If A<B THEN B>A.
+** <li> If A<B and B<C then A<C.
+** </ol>
+**
+** If a collating function fails any of the above constraints and that
+** collating function is registered and used, then the behavior of SQLite
+** is undefined.
+**
+** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
+** with the addition that the xDestroy callback is invoked on pArg when
+** the collating function is deleted.
+** ^Collating functions are deleted when they are overridden by later
+** calls to the collation creation functions or when the
+** [database connection] is closed using [sqlite3_close()].
+**
+** ^The xDestroy callback is <u>not</u> called if the
+** sqlite3_create_collation_v2() function fails.  Applications that invoke
+** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
+** check the return code and dispose of the application data pointer
+** themselves rather than expecting SQLite to deal with it for them.
+** This is different from every other SQLite interface.  The inconsistency
+** is unfortunate but cannot be changed without breaking backwards
+** compatibility.
+**
+** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
+*/
+SQLITE_API int sqlite3_create_collation(
+  sqlite3*,
+  const char *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+SQLITE_API int sqlite3_create_collation_v2(
+  sqlite3*,
+  const char *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDestroy)(void*)
+);
+SQLITE_API int sqlite3_create_collation16(
+  sqlite3*,
+  const void *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+
+/*
+** CAPI3REF: Collation Needed Callbacks
+** METHOD: sqlite3
+**
+** ^To avoid having to register all collation sequences before a database
+** can be used, a single callback function may be registered with the
+** [database connection] to be invoked whenever an undefined collation
+** sequence is required.
+**
+** ^If the function is registered using the sqlite3_collation_needed() API,
+** then it is passed the names of undefined collation sequences as strings
+** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
+** the names are passed as UTF-16 in machine native byte order.
+** ^A call to either function replaces the existing collation-needed callback.
+**
+** ^(When the callback is invoked, the first argument passed is a copy
+** of the second argument to sqlite3_collation_needed() or
+** sqlite3_collation_needed16().  The second argument is the database
+** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
+** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
+** sequence function required.  The fourth parameter is the name of the
+** required collation sequence.)^
+**
+** The callback function should register the desired collation using
+** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
+** [sqlite3_create_collation_v2()].
+*/
+SQLITE_API int sqlite3_collation_needed(
+  sqlite3*,
+  void*,
+  void(*)(void*,sqlite3*,int eTextRep,const char*)
+);
+SQLITE_API int sqlite3_collation_needed16(
+  sqlite3*,
+  void*,
+  void(*)(void*,sqlite3*,int eTextRep,const void*)
+);
+
+#ifdef SQLITE_ENABLE_CEROD
+/*
+** Specify the activation key for a CEROD database.  Unless
+** activated, none of the CEROD routines will work.
+*/
+SQLITE_API void sqlite3_activate_cerod(
+  const char *zPassPhrase        /* Activation phrase */
+);
+#endif
+
+/*
+** CAPI3REF: Suspend Execution For A Short Time
+**
+** The sqlite3_sleep() function causes the current thread to suspend execution
+** for at least a number of milliseconds specified in its parameter.
+**
+** If the operating system does not support sleep requests with
+** millisecond time resolution, then the time will be rounded up to
+** the nearest second. The number of milliseconds of sleep actually
+** requested from the operating system is returned.
+**
+** ^SQLite implements this interface by calling the xSleep()
+** method of the default [sqlite3_vfs] object.  If the xSleep() method
+** of the default VFS is not implemented correctly, or not implemented at
+** all, then the behavior of sqlite3_sleep() may deviate from the description
+** in the previous paragraphs.
+**
+** If a negative argument is passed to sqlite3_sleep() the results vary by
+** VFS and operating system.  Some system treat a negative argument as an
+** instruction to sleep forever.  Others understand it to mean do not sleep
+** at all. ^In SQLite version 3.42.0 and later, a negative
+** argument passed into sqlite3_sleep() is changed to zero before it is relayed
+** down into the xSleep method of the VFS.
+*/
+SQLITE_API int sqlite3_sleep(int);
+
+/*
+** CAPI3REF: Name Of The Folder Holding Temporary Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all temporary files
+** created by SQLite when using a built-in [sqlite3_vfs | VFS]
+** will be placed in that directory.)^  ^If this variable
+** is a NULL pointer, then SQLite performs a search for an appropriate
+** temporary file directory.
+**
+** Applications are strongly discouraged from using this global variable.
+** It is required to set a temporary folder on Windows Runtime (WinRT).
+** But for all other platforms, it is highly recommended that applications
+** neither read nor write this variable.  This global variable is a relic
+** that exists for backwards compatibility of legacy applications and should
+** be avoided in new projects.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [temp_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [temp_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [temp_store_directory pragma] should be avoided.
+** Except when requested by the [temp_store_directory pragma], SQLite
+** does not free the memory that sqlite3_temp_directory points to.  If
+** the application wants that memory to be freed, it must do
+** so itself, taking care to only do so after all [database connection]
+** objects have been destroyed.
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
+** features that require the use of temporary files may fail.  Here is an
+** example of how to do this using C++ with the Windows Runtime:
+**
+** <blockquote><pre>
+** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
+**       TemporaryFolder->Path->Data();
+** char zPathBuf[MAX_PATH + 1];
+** memset(zPathBuf, 0, sizeof(zPathBuf));
+** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
+**       NULL, NULL);
+** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
+** </pre></blockquote>
+*/
+SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
+
+/*
+** CAPI3REF: Name Of The Folder Holding Database Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all database files
+** specified with a relative pathname and created or accessed by
+** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
+** to be relative to that directory.)^ ^If this variable is a NULL
+** pointer, then SQLite assumes that all database files specified
+** with a relative pathname are relative to the current directory
+** for the process.  Only the windows VFS makes use of this global
+** variable; it is ignored by the unix VFS.
+**
+** Changing the value of this variable while a database connection is
+** open can result in a corrupt database.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [data_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [data_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [data_store_directory pragma] should be avoided.
+*/
+SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
+
+/*
+** CAPI3REF: Win32 Specific Interface
+**
+** These interfaces are available only on Windows.  The
+** [sqlite3_win32_set_directory] interface is used to set the value associated
+** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
+** zValue, depending on the value of the type parameter.  The zValue parameter
+** should be NULL to cause the previous value to be freed via [sqlite3_free];
+** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
+** prior to being used.  The [sqlite3_win32_set_directory] interface returns
+** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
+** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
+** [sqlite3_data_directory] variable is intended to act as a replacement for
+** the current directory on the sub-platforms of Win32 where that concept is
+** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
+** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
+** sqlite3_win32_set_directory interface except the string parameter must be
+** UTF-8 or UTF-16, respectively.
+*/
+SQLITE_API int sqlite3_win32_set_directory(
+  unsigned long type, /* Identifier for directory being set or reset */
+  void *zValue        /* New value for directory being set or reset */
+);
+SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
+SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
+
+/*
+** CAPI3REF: Win32 Directory Types
+**
+** These macros are only available on Windows.  They define the allowed values
+** for the type argument to the [sqlite3_win32_set_directory] interface.
+*/
+#define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
+#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
+
+/*
+** CAPI3REF: Test For Auto-Commit Mode
+** KEYWORDS: {autocommit mode}
+** METHOD: sqlite3
+**
+** ^The sqlite3_get_autocommit() interface returns non-zero or
+** zero if the given database connection is or is not in autocommit mode,
+** respectively.  ^Autocommit mode is on by default.
+** ^Autocommit mode is disabled by a [BEGIN] statement.
+** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
+**
+** If certain kinds of errors occur on a statement within a multi-statement
+** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
+** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
+** transaction might be rolled back automatically.  The only way to
+** find out whether SQLite automatically rolled back the transaction after
+** an error is to use this function.
+**
+** If another thread changes the autocommit status of the database
+** connection while this routine is running, then the return value
+** is undefined.
+*/
+SQLITE_API int sqlite3_get_autocommit(sqlite3*);
+
+/*
+** CAPI3REF: Find The Database Handle Of A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_db_handle interface returns the [database connection] handle
+** to which a [prepared statement] belongs.  ^The [database connection]
+** returned by sqlite3_db_handle is the same [database connection]
+** that was the first argument
+** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
+** create the statement in the first place.
+*/
+SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Return The Schema Name For A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
+** for the N-th database on database connection D, or a NULL pointer of N is
+** out of range.  An N value of 0 means the main database file.  An N of 1 is
+** the "temp" schema.  Larger values of N correspond to various ATTACH-ed
+** databases.
+**
+** Space to hold the string that is returned by sqlite3_db_name() is managed
+** by SQLite itself.  The string might be deallocated by any operation that
+** changes the schema, including [ATTACH] or [DETACH] or calls to
+** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
+** occur on a different thread.  Applications that need to
+** remember the string long-term should make their own copy.  Applications that
+** are accessing the same database connection simultaneously on multiple
+** threads should mutex-protect calls to this API and should make their own
+** private copy of the result prior to releasing the mutex.
+*/
+SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Return The Filename For A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
+** associated with database N of connection D.
+** ^If there is no attached database N on the database
+** connection D, or if database N is a temporary or in-memory database, then
+** this function will return either a NULL pointer or an empty string.
+**
+** ^The string value returned by this routine is owned and managed by
+** the database connection.  ^The value will be valid until the database N
+** is [DETACH]-ed or until the database connection closes.
+**
+** ^The filename returned by this function is the output of the
+** xFullPathname method of the [VFS].  ^In other words, the filename
+** will be an absolute pathname, even if the filename used
+** to open the database originally was a URI or relative pathname.
+**
+** If the filename pointer returned by this routine is not NULL, then it
+** can be used as the filename input parameter to these routines:
+** <ul>
+** <li> [sqlite3_uri_parameter()]
+** <li> [sqlite3_uri_boolean()]
+** <li> [sqlite3_uri_int64()]
+** <li> [sqlite3_filename_database()]
+** <li> [sqlite3_filename_journal()]
+** <li> [sqlite3_filename_wal()]
+** </ul>
+*/
+SQLITE_API sqlite3_filename sqlite3_db_filename(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine if a database is read-only
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
+** of connection D is read-only, 0 if it is read/write, or -1 if N is not
+** the name of a database on connection D.
+*/
+SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine the transaction state of a database
+** METHOD: sqlite3
+**
+** ^The sqlite3_txn_state(D,S) interface returns the current
+** [transaction state] of schema S in database connection D.  ^If S is NULL,
+** then the highest transaction state of any schema on database connection D
+** is returned.  Transaction states are (in order of lowest to highest):
+** <ol>
+** <li value="0"> SQLITE_TXN_NONE
+** <li value="1"> SQLITE_TXN_READ
+** <li value="2"> SQLITE_TXN_WRITE
+** </ol>
+** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
+** a valid schema, then -1 is returned.
+*/
+SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
+
+/*
+** CAPI3REF: Allowed return values from sqlite3_txn_state()
+** KEYWORDS: {transaction state}
+**
+** These constants define the current transaction state of a database file.
+** ^The [sqlite3_txn_state(D,S)] interface returns one of these
+** constants in order to describe the transaction state of schema S
+** in [database connection] D.
+**
+** <dl>
+** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
+** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
+** pending.</dd>
+**
+** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
+** <dd>The SQLITE_TXN_READ state means that the database is currently
+** in a read transaction.  Content has been read from the database file
+** but nothing in the database file has changed.  The transaction state
+** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
+** no other conflicting concurrent write transactions.  The transaction
+** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
+** [COMMIT].</dd>
+**
+** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
+** <dd>The SQLITE_TXN_WRITE state means that the database is currently
+** in a write transaction.  Content has been written to the database file
+** but has not yet committed.  The transaction state will change to
+** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
+*/
+#define SQLITE_TXN_NONE  0
+#define SQLITE_TXN_READ  1
+#define SQLITE_TXN_WRITE 2
+
+/*
+** CAPI3REF: Find the next prepared statement
+** METHOD: sqlite3
+**
+** ^This interface returns a pointer to the next [prepared statement] after
+** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
+** then this interface returns a pointer to the first prepared statement
+** associated with the database connection pDb.  ^If no prepared statement
+** satisfies the conditions of this routine, it returns NULL.
+**
+** The [database connection] pointer D in a call to
+** [sqlite3_next_stmt(D,S)] must refer to an open database
+** connection and in particular must not be a NULL pointer.
+*/
+SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Commit And Rollback Notification Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_commit_hook() interface registers a callback
+** function to be invoked whenever a transaction is [COMMIT | committed].
+** ^Any callback set by a previous call to sqlite3_commit_hook()
+** for the same database connection is overridden.
+** ^The sqlite3_rollback_hook() interface registers a callback
+** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
+** ^Any callback set by a previous call to sqlite3_rollback_hook()
+** for the same database connection is overridden.
+** ^The pArg argument is passed through to the callback.
+** ^If the callback on a commit hook function returns non-zero,
+** then the commit is converted into a rollback.
+**
+** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
+** return the P argument from the previous call of the same function
+** on the same [database connection] D, or NULL for
+** the first call for each function on D.
+**
+** The commit and rollback hook callbacks are not reentrant.
+** The callback implementation must not do anything that will modify
+** the database connection that invoked the callback.  Any actions
+** to modify the database connection must be deferred until after the
+** completion of the [sqlite3_step()] call that triggered the commit
+** or rollback hook in the first place.
+** Note that running any other SQL statements, including SELECT statements,
+** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
+** the database connections for the meaning of "modify" in this paragraph.
+**
+** ^Registering a NULL function disables the callback.
+**
+** ^When the commit hook callback routine returns zero, the [COMMIT]
+** operation is allowed to continue normally.  ^If the commit hook
+** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
+** ^The rollback hook is invoked on a rollback that results from a commit
+** hook returning non-zero, just as it would be with any other rollback.
+**
+** ^For the purposes of this API, a transaction is said to have been
+** rolled back if an explicit "ROLLBACK" statement is executed, or
+** an error or constraint causes an implicit rollback to occur.
+** ^The rollback callback is not invoked if a transaction is
+** automatically rolled back because the database connection is closed.
+**
+** See also the [sqlite3_update_hook()] interface.
+*/
+SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
+SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
+
+/*
+** CAPI3REF: Autovacuum Compaction Amount Callback
+** METHOD: sqlite3
+**
+** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
+** function C that is invoked prior to each autovacuum of the database
+** file.  ^The callback is passed a copy of the generic data pointer (P),
+** the schema-name of the attached database that is being autovacuumed,
+** the size of the database file in pages, the number of free pages,
+** and the number of bytes per page, respectively.  The callback should
+** return the number of free pages that should be removed by the
+** autovacuum.  ^If the callback returns zero, then no autovacuum happens.
+** ^If the value returned is greater than or equal to the number of
+** free pages, then a complete autovacuum happens.
+**
+** <p>^If there are multiple ATTACH-ed database files that are being
+** modified as part of a transaction commit, then the autovacuum pages
+** callback is invoked separately for each file.
+**
+** <p><b>The callback is not reentrant.</b> The callback function should
+** not attempt to invoke any other SQLite interface.  If it does, bad
+** things may happen, including segmentation faults and corrupt database
+** files.  The callback function should be a simple function that
+** does some arithmetic on its input parameters and returns a result.
+**
+** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
+** destructor for the P parameter.  ^If X is not NULL, then X(P) is
+** invoked whenever the database connection closes or when the callback
+** is overwritten by another invocation of sqlite3_autovacuum_pages().
+**
+** <p>^There is only one autovacuum pages callback per database connection.
+** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
+** previous invocations for that database connection.  ^If the callback
+** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
+** then the autovacuum steps callback is canceled.  The return value
+** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
+** be some other error code if something goes wrong.  The current
+** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
+** return codes might be added in future releases.
+**
+** <p>If no autovacuum pages callback is specified (the usual case) or
+** a NULL pointer is provided for the callback,
+** then the default behavior is to vacuum all free pages.  So, in other
+** words, the default behavior is the same as if the callback function
+** were something like this:
+**
+** <blockquote><pre>
+**     unsigned int demonstration_autovac_pages_callback(
+**       void *pClientData,
+**       const char *zSchema,
+**       unsigned int nDbPage,
+**       unsigned int nFreePage,
+**       unsigned int nBytePerPage
+**     ){
+**       return nFreePage;
+**     }
+** </pre></blockquote>
+*/
+SQLITE_API int sqlite3_autovacuum_pages(
+  sqlite3 *db,
+  unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
+  void*,
+  void(*)(void*)
+);
+
+
+/*
+** CAPI3REF: Data Change Notification Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_update_hook() interface registers a callback function
+** with the [database connection] identified by the first argument
+** to be invoked whenever a row is updated, inserted or deleted in
+** a [rowid table].
+** ^Any callback set by a previous call to this function
+** for the same database connection is overridden.
+**
+** ^The second argument is a pointer to the function to invoke when a
+** row is updated, inserted or deleted in a rowid table.
+** ^The first argument to the callback is a copy of the third argument
+** to sqlite3_update_hook().
+** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
+** or [SQLITE_UPDATE], depending on the operation that caused the callback
+** to be invoked.
+** ^The third and fourth arguments to the callback contain pointers to the
+** database and table name containing the affected row.
+** ^The final callback parameter is the [rowid] of the row.
+** ^In the case of an update, this is the [rowid] after the update takes place.
+**
+** ^(The update hook is not invoked when internal system tables are
+** modified (i.e. sqlite_sequence).)^
+** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
+**
+** ^In the current implementation, the update hook
+** is not invoked when conflicting rows are deleted because of an
+** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
+** invoked when rows are deleted using the [truncate optimization].
+** The exceptions defined in this paragraph might change in a future
+** release of SQLite.
+**
+** Whether the update hook is invoked before or after the
+** corresponding change is currently unspecified and may differ
+** depending on the type of change. Do not rely on the order of the
+** hook call with regards to the final result of the operation which
+** triggers the hook.
+**
+** The update hook implementation must not do anything that will modify
+** the database connection that invoked the update hook.  Any actions
+** to modify the database connection must be deferred until after the
+** completion of the [sqlite3_step()] call that triggered the update hook.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** ^The sqlite3_update_hook(D,C,P) function
+** returns the P argument from the previous call
+** on the same [database connection] D, or NULL for
+** the first call on D.
+**
+** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
+** and [sqlite3_preupdate_hook()] interfaces.
+*/
+SQLITE_API void *sqlite3_update_hook(
+  sqlite3*,
+  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
+  void*
+);
+
+/*
+** CAPI3REF: Enable Or Disable Shared Pager Cache
+**
+** ^(This routine enables or disables the sharing of the database cache
+** and schema data structures between [database connection | connections]
+** to the same database. Sharing is enabled if the argument is true
+** and disabled if the argument is false.)^
+**
+** This interface is omitted if SQLite is compiled with
+** [-DSQLITE_OMIT_SHARED_CACHE].  The [-DSQLITE_OMIT_SHARED_CACHE]
+** compile-time option is recommended because the
+** [use of shared cache mode is discouraged].
+**
+** ^Cache sharing is enabled and disabled for an entire process.
+** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
+** In prior versions of SQLite,
+** sharing was enabled or disabled for each thread separately.
+**
+** ^(The cache sharing mode set by this interface effects all subsequent
+** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
+** Existing database connections continue to use the sharing mode
+** that was in effect at the time they were opened.)^
+**
+** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
+** successfully.  An [error code] is returned otherwise.)^
+**
+** ^Shared cache is disabled by default. It is recommended that it stay
+** that way.  In other words, do not use this routine.  This interface
+** continues to be provided for historical compatibility, but its use is
+** discouraged.  Any use of shared cache is discouraged.  If shared cache
+** must be used, it is recommended that shared cache only be enabled for
+** individual database connections using the [sqlite3_open_v2()] interface
+** with the [SQLITE_OPEN_SHAREDCACHE] flag.
+**
+** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
+** and will always return SQLITE_MISUSE. On those systems,
+** shared cache mode should be enabled per-database connection via
+** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
+**
+** This interface is threadsafe on processors where writing a
+** 32-bit integer is atomic.
+**
+** See Also:  [SQLite Shared-Cache Mode]
+*/
+SQLITE_API int sqlite3_enable_shared_cache(int);
+
+/*
+** CAPI3REF: Attempt To Free Heap Memory
+**
+** ^The sqlite3_release_memory() interface attempts to free N bytes
+** of heap memory by deallocating non-essential memory allocations
+** held by the database library.   Memory used to cache database
+** pages to improve performance is an example of non-essential memory.
+** ^sqlite3_release_memory() returns the number of bytes actually freed,
+** which might be more or less than the amount requested.
+** ^The sqlite3_release_memory() routine is a no-op returning zero
+** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
+**
+** See also: [sqlite3_db_release_memory()]
+*/
+SQLITE_API int sqlite3_release_memory(int);
+
+/*
+** CAPI3REF: Free Memory Used By A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
+** memory as possible from database connection D. Unlike the
+** [sqlite3_release_memory()] interface, this interface is in effect even
+** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
+** omitted.
+**
+** See also: [sqlite3_release_memory()]
+*/
+SQLITE_API int sqlite3_db_release_memory(sqlite3*);
+
+/*
+** CAPI3REF: Impose A Limit On Heap Size
+**
+** These interfaces impose limits on the amount of heap memory that will be
+** by all database connections within a single process.
+**
+** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
+** soft limit on the amount of heap memory that may be allocated by SQLite.
+** ^SQLite strives to keep heap memory utilization below the soft heap
+** limit by reducing the number of pages held in the page cache
+** as heap memory usages approaches the limit.
+** ^The soft heap limit is "soft" because even though SQLite strives to stay
+** below the limit, it will exceed the limit rather than generate
+** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
+** is advisory only.
+**
+** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
+** N bytes on the amount of memory that will be allocated.  ^The
+** sqlite3_hard_heap_limit64(N) interface is similar to
+** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
+** when the hard heap limit is reached.
+**
+** ^The return value from both sqlite3_soft_heap_limit64() and
+** sqlite3_hard_heap_limit64() is the size of
+** the heap limit prior to the call, or negative in the case of an
+** error.  ^If the argument N is negative
+** then no change is made to the heap limit.  Hence, the current
+** size of heap limits can be determined by invoking
+** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
+**
+** ^Setting the heap limits to zero disables the heap limiter mechanism.
+**
+** ^The soft heap limit may not be greater than the hard heap limit.
+** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
+** is invoked with a value of N that is greater than the hard heap limit,
+** the soft heap limit is set to the value of the hard heap limit.
+** ^The soft heap limit is automatically enabled whenever the hard heap
+** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
+** the soft heap limit is outside the range of 1..N, then the soft heap
+** limit is set to N.  ^Invoking sqlite3_soft_heap_limit64(0) when the
+** hard heap limit is enabled makes the soft heap limit equal to the
+** hard heap limit.
+**
+** The memory allocation limits can also be adjusted using
+** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
+**
+** ^(The heap limits are not enforced in the current implementation
+** if one or more of following conditions are true:
+**
+** <ul>
+** <li> The limit value is set to zero.
+** <li> Memory accounting is disabled using a combination of the
+**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
+**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
+** <li> An alternative page cache implementation is specified using
+**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
+** <li> The page cache allocates from its own memory pool supplied
+**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
+**      from the heap.
+** </ul>)^
+**
+** The circumstances under which SQLite will enforce the heap limits may
+** changes in future releases of SQLite.
+*/
+SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
+SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
+
+/*
+** CAPI3REF: Deprecated Soft Heap Limit Interface
+** DEPRECATED
+**
+** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
+** interface.  This routine is provided for historical compatibility
+** only.  All new applications should use the
+** [sqlite3_soft_heap_limit64()] interface rather than this one.
+*/
+SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
+
+
+/*
+** CAPI3REF: Extract Metadata About A Column Of A Table
+** METHOD: sqlite3
+**
+** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
+** information about column C of table T in database D
+** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
+** interface returns SQLITE_OK and fills in the non-NULL pointers in
+** the final five arguments with appropriate values if the specified
+** column exists.  ^The sqlite3_table_column_metadata() interface returns
+** SQLITE_ERROR if the specified column does not exist.
+** ^If the column-name parameter to sqlite3_table_column_metadata() is a
+** NULL pointer, then this routine simply checks for the existence of the
+** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
+** does not.  If the table name parameter T in a call to
+** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
+** undefined behavior.
+**
+** ^The column is identified by the second, third and fourth parameters to
+** this function. ^(The second parameter is either the name of the database
+** (i.e. "main", "temp", or an attached database) containing the specified
+** table or NULL.)^ ^If it is NULL, then all attached databases are searched
+** for the table using the same algorithm used by the database engine to
+** resolve unqualified table references.
+**
+** ^The third and fourth parameters to this function are the table and column
+** name of the desired column, respectively.
+**
+** ^Metadata is returned by writing to the memory locations passed as the 5th
+** and subsequent parameters to this function. ^Any of these arguments may be
+** NULL, in which case the corresponding element of metadata is omitted.
+**
+** ^(<blockquote>
+** <table border="1">
+** <tr><th> Parameter <th> Output<br>Type <th>  Description
+**
+** <tr><td> 5th <td> const char* <td> Data type
+** <tr><td> 6th <td> const char* <td> Name of default collation sequence
+** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
+** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
+** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
+** </table>
+** </blockquote>)^
+**
+** ^The memory pointed to by the character pointers returned for the
+** declaration type and collation sequence is valid until the next
+** call to any SQLite API function.
+**
+** ^If the specified table is actually a view, an [error code] is returned.
+**
+** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
+** is not a [WITHOUT ROWID] table and an
+** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
+** parameters are set for the explicitly declared column. ^(If there is no
+** [INTEGER PRIMARY KEY] column, then the outputs
+** for the [rowid] are set as follows:
+**
+** <pre>
+**     data type: "INTEGER"
+**     collation sequence: "BINARY"
+**     not null: 0
+**     primary key: 1
+**     auto increment: 0
+** </pre>)^
+**
+** ^This function causes all database schemas to be read from disk and
+** parsed, if that has not already been done, and returns an error if
+** any errors are encountered while loading the schema.
+*/
+SQLITE_API int sqlite3_table_column_metadata(
+  sqlite3 *db,                /* Connection handle */
+  const char *zDbName,        /* Database name or NULL */
+  const char *zTableName,     /* Table name */
+  const char *zColumnName,    /* Column name */
+  char const **pzDataType,    /* OUTPUT: Declared data type */
+  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
+  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
+  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
+  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
+);
+
+/*
+** CAPI3REF: Load An Extension
+** METHOD: sqlite3
+**
+** ^This interface loads an SQLite extension library from the named file.
+**
+** ^The sqlite3_load_extension() interface attempts to load an
+** [SQLite extension] library contained in the file zFile.  If
+** the file cannot be loaded directly, attempts are made to load
+** with various operating-system specific extensions added.
+** So for example, if "samplelib" cannot be loaded, then names like
+** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
+** be tried also.
+**
+** ^The entry point is zProc.
+** ^(zProc may be 0, in which case SQLite will try to come up with an
+** entry point name on its own.  It first tries "sqlite3_extension_init".
+** If that does not work, it constructs a name "sqlite3_X_init" where the
+** X is consists of the lower-case equivalent of all ASCII alphabetic
+** characters in the filename from the last "/" to the first following
+** "." and omitting any initial "lib".)^
+** ^The sqlite3_load_extension() interface returns
+** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
+** ^If an error occurs and pzErrMsg is not 0, then the
+** [sqlite3_load_extension()] interface shall attempt to
+** fill *pzErrMsg with error message text stored in memory
+** obtained from [sqlite3_malloc()]. The calling function
+** should free this memory by calling [sqlite3_free()].
+**
+** ^Extension loading must be enabled using
+** [sqlite3_enable_load_extension()] or
+** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
+** prior to calling this API,
+** otherwise an error will be returned.
+**
+** <b>Security warning:</b> It is recommended that the
+** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
+** interface.  The use of the [sqlite3_enable_load_extension()] interface
+** should be avoided.  This will keep the SQL function [load_extension()]
+** disabled and prevent SQL injections from giving attackers
+** access to extension loading capabilities.
+**
+** See also the [load_extension() SQL function].
+*/
+SQLITE_API int sqlite3_load_extension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+);
+
+/*
+** CAPI3REF: Enable Or Disable Extension Loading
+** METHOD: sqlite3
+**
+** ^So as not to open security holes in older applications that are
+** unprepared to deal with [extension loading], and as a means of disabling
+** [extension loading] while evaluating user-entered SQL, the following API
+** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
+**
+** ^Extension loading is off by default.
+** ^Call the sqlite3_enable_load_extension() routine with onoff==1
+** to turn extension loading on and call it with onoff==0 to turn
+** it back off again.
+**
+** ^This interface enables or disables both the C-API
+** [sqlite3_load_extension()] and the SQL function [load_extension()].
+** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
+** to enable or disable only the C-API.)^
+**
+** <b>Security warning:</b> It is recommended that extension loading
+** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
+** rather than this interface, so the [load_extension()] SQL function
+** remains disabled. This will prevent SQL injections from giving attackers
+** access to extension loading capabilities.
+*/
+SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
+
+/*
+** CAPI3REF: Automatically Load Statically Linked Extensions
+**
+** ^This interface causes the xEntryPoint() function to be invoked for
+** each new [database connection] that is created.  The idea here is that
+** xEntryPoint() is the entry point for a statically linked [SQLite extension]
+** that is to be automatically loaded into all new database connections.
+**
+** ^(Even though the function prototype shows that xEntryPoint() takes
+** no arguments and returns void, SQLite invokes xEntryPoint() with three
+** arguments and expects an integer result as if the signature of the
+** entry point where as follows:
+**
+** <blockquote><pre>
+**    int xEntryPoint(
+**      sqlite3 *db,
+**      const char **pzErrMsg,
+**      const struct sqlite3_api_routines *pThunk
+**    );
+** </pre></blockquote>)^
+**
+** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
+** point to an appropriate error message (obtained from [sqlite3_mprintf()])
+** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
+** is NULL before calling the xEntryPoint().  ^SQLite will invoke
+** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
+** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
+** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
+**
+** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
+** on the list of automatic extensions is a harmless no-op. ^No entry point
+** will be called more than once for each database connection that is opened.
+**
+** See also: [sqlite3_reset_auto_extension()]
+** and [sqlite3_cancel_auto_extension()]
+*/
+SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
+
+/*
+** CAPI3REF: Cancel Automatic Extension Loading
+**
+** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
+** initialization routine X that was registered using a prior call to
+** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
+** routine returns 1 if initialization routine X was successfully
+** unregistered and it returns 0 if X was not on the list of initialization
+** routines.
+*/
+SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
+
+/*
+** CAPI3REF: Reset Automatic Extension Loading
+**
+** ^This interface disables all automatic extensions previously
+** registered using [sqlite3_auto_extension()].
+*/
+SQLITE_API void sqlite3_reset_auto_extension(void);
+
+/*
+** Structures used by the virtual table interface
+*/
+typedef struct sqlite3_vtab sqlite3_vtab;
+typedef struct sqlite3_index_info sqlite3_index_info;
+typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
+typedef struct sqlite3_module sqlite3_module;
+
+/*
+** CAPI3REF: Virtual Table Object
+** KEYWORDS: sqlite3_module {virtual table module}
+**
+** This structure, sometimes called a "virtual table module",
+** defines the implementation of a [virtual table].
+** This structure consists mostly of methods for the module.
+**
+** ^A virtual table module is created by filling in a persistent
+** instance of this structure and passing a pointer to that instance
+** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
+** ^The registration remains valid until it is replaced by a different
+** module or until the [database connection] closes.  The content
+** of this structure must not change while it is registered with
+** any database connection.
+*/
+struct sqlite3_module {
+  int iVersion;
+  int (*xCreate)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xConnect)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
+  int (*xDisconnect)(sqlite3_vtab *pVTab);
+  int (*xDestroy)(sqlite3_vtab *pVTab);
+  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
+  int (*xClose)(sqlite3_vtab_cursor*);
+  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
+                int argc, sqlite3_value **argv);
+  int (*xNext)(sqlite3_vtab_cursor*);
+  int (*xEof)(sqlite3_vtab_cursor*);
+  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
+  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
+  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
+  int (*xBegin)(sqlite3_vtab *pVTab);
+  int (*xSync)(sqlite3_vtab *pVTab);
+  int (*xCommit)(sqlite3_vtab *pVTab);
+  int (*xRollback)(sqlite3_vtab *pVTab);
+  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
+                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
+                       void **ppArg);
+  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
+  /* The methods above are in version 1 of the sqlite_module object. Those
+  ** below are for version 2 and greater. */
+  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
+  int (*xRelease)(sqlite3_vtab *pVTab, int);
+  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
+  /* The methods above are in versions 1 and 2 of the sqlite_module object.
+  ** Those below are for version 3 and greater. */
+  int (*xShadowName)(const char*);
+  /* The methods above are in versions 1 through 3 of the sqlite_module object.
+  ** Those below are for version 4 and greater. */
+  int (*xIntegrity)(sqlite3_vtab *pVTab, const char *zSchema,
+                    const char *zTabName, int mFlags, char **pzErr);
+};
+
+/*
+** CAPI3REF: Virtual Table Indexing Information
+** KEYWORDS: sqlite3_index_info
+**
+** The sqlite3_index_info structure and its substructures is used as part
+** of the [virtual table] interface to
+** pass information into and receive the reply from the [xBestIndex]
+** method of a [virtual table module].  The fields under **Inputs** are the
+** inputs to xBestIndex and are read-only.  xBestIndex inserts its
+** results into the **Outputs** fields.
+**
+** ^(The aConstraint[] array records WHERE clause constraints of the form:
+**
+** <blockquote>column OP expr</blockquote>
+**
+** where OP is =, <, <=, >, or >=.)^  ^(The particular operator is
+** stored in aConstraint[].op using one of the
+** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
+** ^(The index of the column is stored in
+** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
+** expr on the right-hand side can be evaluated (and thus the constraint
+** is usable) and false if it cannot.)^
+**
+** ^The optimizer automatically inverts terms of the form "expr OP column"
+** and makes other simplifications to the WHERE clause in an attempt to
+** get as many WHERE clause terms into the form shown above as possible.
+** ^The aConstraint[] array only reports WHERE clause terms that are
+** relevant to the particular virtual table being queried.
+**
+** ^Information about the ORDER BY clause is stored in aOrderBy[].
+** ^Each term of aOrderBy records a column of the ORDER BY clause.
+**
+** The colUsed field indicates which columns of the virtual table may be
+** required by the current scan. Virtual table columns are numbered from
+** zero in the order in which they appear within the CREATE TABLE statement
+** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
+** the corresponding bit is set within the colUsed mask if the column may be
+** required by SQLite. If the table has at least 64 columns and any column
+** to the right of the first 63 is required, then bit 63 of colUsed is also
+** set. In other words, column iCol may be required if the expression
+** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
+** non-zero.
+**
+** The [xBestIndex] method must fill aConstraintUsage[] with information
+** about what parameters to pass to xFilter.  ^If argvIndex>0 then
+** the right-hand side of the corresponding aConstraint[] is evaluated
+** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
+** is true, then the constraint is assumed to be fully handled by the
+** virtual table and might not be checked again by the byte code.)^ ^(The
+** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
+** is left in its default setting of false, the constraint will always be
+** checked separately in byte code.  If the omit flag is change to true, then
+** the constraint may or may not be checked in byte code.  In other words,
+** when the omit flag is true there is no guarantee that the constraint will
+** not be checked again using byte code.)^
+**
+** ^The idxNum and idxStr values are recorded and passed into the
+** [xFilter] method.
+** ^[sqlite3_free()] is used to free idxStr if and only if
+** needToFreeIdxStr is true.
+**
+** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
+** the correct order to satisfy the ORDER BY clause so that no separate
+** sorting step is required.
+**
+** ^The estimatedCost value is an estimate of the cost of a particular
+** strategy. A cost of N indicates that the cost of the strategy is similar
+** to a linear scan of an SQLite table with N rows. A cost of log(N)
+** indicates that the expense of the operation is similar to that of a
+** binary search on a unique indexed field of an SQLite table with N rows.
+**
+** ^The estimatedRows value is an estimate of the number of rows that
+** will be returned by the strategy.
+**
+** The xBestIndex method may optionally populate the idxFlags field with a
+** mask of SQLITE_INDEX_SCAN_* flags. One such flag is
+** [SQLITE_INDEX_SCAN_HEX], which if set causes the [EXPLAIN QUERY PLAN]
+** output to show the idxNum has hex instead of as decimal.  Another flag is
+** SQLITE_INDEX_SCAN_UNIQUE, which if set indicates that the query plan will
+** return at most one row.
+**
+** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
+** SQLite also assumes that if a call to the xUpdate() method is made as
+** part of the same statement to delete or update a virtual table row and the
+** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
+** any database changes. In other words, if the xUpdate() returns
+** SQLITE_CONSTRAINT, the database contents must be exactly as they were
+** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
+** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
+** the xUpdate method are automatically rolled back by SQLite.
+**
+** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
+** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
+** If a virtual table extension is
+** used with an SQLite version earlier than 3.8.2, the results of attempting
+** to read or write the estimatedRows field are undefined (but are likely
+** to include crashing the application). The estimatedRows field should
+** therefore only be used if [sqlite3_libversion_number()] returns a
+** value greater than or equal to 3008002. Similarly, the idxFlags field
+** was added for [version 3.9.0] ([dateof:3.9.0]).
+** It may therefore only be used if
+** sqlite3_libversion_number() returns a value greater than or equal to
+** 3009000.
+*/
+struct sqlite3_index_info {
+  /* Inputs */
+  int nConstraint;           /* Number of entries in aConstraint */
+  struct sqlite3_index_constraint {
+     int iColumn;              /* Column constrained.  -1 for ROWID */
+     unsigned char op;         /* Constraint operator */
+     unsigned char usable;     /* True if this constraint is usable */
+     int iTermOffset;          /* Used internally - xBestIndex should ignore */
+  } *aConstraint;            /* Table of WHERE clause constraints */
+  int nOrderBy;              /* Number of terms in the ORDER BY clause */
+  struct sqlite3_index_orderby {
+     int iColumn;              /* Column number */
+     unsigned char desc;       /* True for DESC.  False for ASC. */
+  } *aOrderBy;               /* The ORDER BY clause */
+  /* Outputs */
+  struct sqlite3_index_constraint_usage {
+    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
+    unsigned char omit;      /* Do not code a test for this constraint */
+  } *aConstraintUsage;
+  int idxNum;                /* Number used to identify the index */
+  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
+  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
+  int orderByConsumed;       /* True if output is already ordered */
+  double estimatedCost;           /* Estimated cost of using this index */
+  /* Fields below are only available in SQLite 3.8.2 and later */
+  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
+  /* Fields below are only available in SQLite 3.9.0 and later */
+  int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
+  /* Fields below are only available in SQLite 3.10.0 and later */
+  sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
+};
+
+/*
+** CAPI3REF: Virtual Table Scan Flags
+**
+** Virtual table implementations are allowed to set the
+** [sqlite3_index_info].idxFlags field to some combination of
+** these bits.
+*/
+#define SQLITE_INDEX_SCAN_UNIQUE 0x00000001 /* Scan visits at most 1 row */
+#define SQLITE_INDEX_SCAN_HEX    0x00000002 /* Display idxNum as hex */
+                                            /* in EXPLAIN QUERY PLAN */
+
+/*
+** CAPI3REF: Virtual Table Constraint Operator Codes
+**
+** These macros define the allowed values for the
+** [sqlite3_index_info].aConstraint[].op field.  Each value represents
+** an operator that is part of a constraint term in the WHERE clause of
+** a query that uses a [virtual table].
+**
+** ^The left-hand operand of the operator is given by the corresponding
+** aConstraint[].iColumn field.  ^An iColumn of -1 indicates the left-hand
+** operand is the rowid.
+** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
+** operators have no left-hand operand, and so for those operators the
+** corresponding aConstraint[].iColumn is meaningless and should not be
+** used.
+**
+** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
+** value 255 are reserved to represent functions that are overloaded
+** by the [xFindFunction|xFindFunction method] of the virtual table
+** implementation.
+**
+** The right-hand operands for each constraint might be accessible using
+** the [sqlite3_vtab_rhs_value()] interface.  Usually the right-hand
+** operand is only available if it appears as a single constant literal
+** in the input SQL.  If the right-hand operand is another column or an
+** expression (even a constant expression) or a parameter, then the
+** sqlite3_vtab_rhs_value() probably will not be able to extract it.
+** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
+** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
+** and hence calls to sqlite3_vtab_rhs_value() for those operators will
+** always return SQLITE_NOTFOUND.
+**
+** The collating sequence to be used for comparison can be found using
+** the [sqlite3_vtab_collation()] interface.  For most real-world virtual
+** tables, the collating sequence of constraints does not matter (for example
+** because the constraints are numeric) and so the sqlite3_vtab_collation()
+** interface is not commonly needed.
+*/
+#define SQLITE_INDEX_CONSTRAINT_EQ          2
+#define SQLITE_INDEX_CONSTRAINT_GT          4
+#define SQLITE_INDEX_CONSTRAINT_LE          8
+#define SQLITE_INDEX_CONSTRAINT_LT         16
+#define SQLITE_INDEX_CONSTRAINT_GE         32
+#define SQLITE_INDEX_CONSTRAINT_MATCH      64
+#define SQLITE_INDEX_CONSTRAINT_LIKE       65
+#define SQLITE_INDEX_CONSTRAINT_GLOB       66
+#define SQLITE_INDEX_CONSTRAINT_REGEXP     67
+#define SQLITE_INDEX_CONSTRAINT_NE         68
+#define SQLITE_INDEX_CONSTRAINT_ISNOT      69
+#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL  70
+#define SQLITE_INDEX_CONSTRAINT_ISNULL     71
+#define SQLITE_INDEX_CONSTRAINT_IS         72
+#define SQLITE_INDEX_CONSTRAINT_LIMIT      73
+#define SQLITE_INDEX_CONSTRAINT_OFFSET     74
+#define SQLITE_INDEX_CONSTRAINT_FUNCTION  150
+
+/*
+** CAPI3REF: Register A Virtual Table Implementation
+** METHOD: sqlite3
+**
+** ^These routines are used to register a new [virtual table module] name.
+** ^Module names must be registered before
+** creating a new [virtual table] using the module and before using a
+** preexisting [virtual table] for the module.
+**
+** ^The module name is registered on the [database connection] specified
+** by the first parameter.  ^The name of the module is given by the
+** second parameter.  ^The third parameter is a pointer to
+** the implementation of the [virtual table module].   ^The fourth
+** parameter is an arbitrary client data pointer that is passed through
+** into the [xCreate] and [xConnect] methods of the virtual table module
+** when a new virtual table is be being created or reinitialized.
+**
+** ^The sqlite3_create_module_v2() interface has a fifth parameter which
+** is a pointer to a destructor for the pClientData.  ^SQLite will
+** invoke the destructor function (if it is not NULL) when SQLite
+** no longer needs the pClientData pointer.  ^The destructor will also
+** be invoked if the call to sqlite3_create_module_v2() fails.
+** ^The sqlite3_create_module()
+** interface is equivalent to sqlite3_create_module_v2() with a NULL
+** destructor.
+**
+** ^If the third parameter (the pointer to the sqlite3_module object) is
+** NULL then no new module is created and any existing modules with the
+** same name are dropped.
+**
+** See also: [sqlite3_drop_modules()]
+*/
+SQLITE_API int sqlite3_create_module(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData          /* Client data for xCreate/xConnect */
+);
+SQLITE_API int sqlite3_create_module_v2(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData,         /* Client data for xCreate/xConnect */
+  void(*xDestroy)(void*)     /* Module destructor function */
+);
+
+/*
+** CAPI3REF: Remove Unnecessary Virtual Table Implementations
+** METHOD: sqlite3
+**
+** ^The sqlite3_drop_modules(D,L) interface removes all virtual
+** table modules from database connection D except those named on list L.
+** The L parameter must be either NULL or a pointer to an array of pointers
+** to strings where the array is terminated by a single NULL pointer.
+** ^If the L parameter is NULL, then all virtual table modules are removed.
+**
+** See also: [sqlite3_create_module()]
+*/
+SQLITE_API int sqlite3_drop_modules(
+  sqlite3 *db,                /* Remove modules from this connection */
+  const char **azKeep         /* Except, do not remove the ones named here */
+);
+
+/*
+** CAPI3REF: Virtual Table Instance Object
+** KEYWORDS: sqlite3_vtab
+**
+** Every [virtual table module] implementation uses a subclass
+** of this object to describe a particular instance
+** of the [virtual table].  Each subclass will
+** be tailored to the specific needs of the module implementation.
+** The purpose of this superclass is to define certain fields that are
+** common to all module implementations.
+**
+** ^Virtual tables methods can set an error message by assigning a
+** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
+** take care that any prior string is freed by a call to [sqlite3_free()]
+** prior to assigning a new string to zErrMsg.  ^After the error message
+** is delivered up to the client application, the string will be automatically
+** freed by sqlite3_free() and the zErrMsg field will be zeroed.
+*/
+struct sqlite3_vtab {
+  const sqlite3_module *pModule;  /* The module for this virtual table */
+  int nRef;                       /* Number of open cursors */
+  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Virtual Table Cursor Object
+** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
+**
+** Every [virtual table module] implementation uses a subclass of the
+** following structure to describe cursors that point into the
+** [virtual table] and are used
+** to loop through the virtual table.  Cursors are created using the
+** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
+** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
+** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
+** of the module.  Each module implementation will define
+** the content of a cursor structure to suit its own needs.
+**
+** This superclass exists in order to define fields of the cursor that
+** are common to all implementations.
+*/
+struct sqlite3_vtab_cursor {
+  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Declare The Schema Of A Virtual Table
+**
+** ^The [xCreate] and [xConnect] methods of a
+** [virtual table module] call this interface
+** to declare the format (the names and datatypes of the columns) of
+** the virtual tables they implement.
+*/
+SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
+
+/*
+** CAPI3REF: Overload A Function For A Virtual Table
+** METHOD: sqlite3
+**
+** ^(Virtual tables can provide alternative implementations of functions
+** using the [xFindFunction] method of the [virtual table module].
+** But global versions of those functions
+** must exist in order to be overloaded.)^
+**
+** ^(This API makes sure a global version of a function with a particular
+** name and number of parameters exists.  If no such function exists
+** before this API is called, a new function is created.)^  ^The implementation
+** of the new function always causes an exception to be thrown.  So
+** the new function is not good for anything by itself.  Its only
+** purpose is to be a placeholder function that can be overloaded
+** by a [virtual table].
+*/
+SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
+
+/*
+** CAPI3REF: A Handle To An Open BLOB
+** KEYWORDS: {BLOB handle} {BLOB handles}
+**
+** An instance of this object represents an open BLOB on which
+** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
+** ^Objects of this type are created by [sqlite3_blob_open()]
+** and destroyed by [sqlite3_blob_close()].
+** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
+** can be used to read or write small subsections of the BLOB.
+** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
+*/
+typedef struct sqlite3_blob sqlite3_blob;
+
+/*
+** CAPI3REF: Open A BLOB For Incremental I/O
+** METHOD: sqlite3
+** CONSTRUCTOR: sqlite3_blob
+**
+** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
+** in row iRow, column zColumn, table zTable in database zDb;
+** in other words, the same BLOB that would be selected by:
+**
+** <pre>
+**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
+** </pre>)^
+**
+** ^(Parameter zDb is not the filename that contains the database, but
+** rather the symbolic name of the database. For attached databases, this is
+** the name that appears after the AS keyword in the [ATTACH] statement.
+** For the main database file, the database name is "main". For TEMP
+** tables, the database name is "temp".)^
+**
+** ^If the flags parameter is non-zero, then the BLOB is opened for read
+** and write access. ^If the flags parameter is zero, the BLOB is opened for
+** read-only access.
+**
+** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
+** in *ppBlob. Otherwise an [error code] is returned and, unless the error
+** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
+** the API is not misused, it is always safe to call [sqlite3_blob_close()]
+** on *ppBlob after this function it returns.
+**
+** This function fails with SQLITE_ERROR if any of the following are true:
+** <ul>
+**   <li> ^(Database zDb does not exist)^,
+**   <li> ^(Table zTable does not exist within database zDb)^,
+**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
+**   <li> ^(Column zColumn does not exist)^,
+**   <li> ^(Row iRow is not present in the table)^,
+**   <li> ^(The specified column of row iRow contains a value that is not
+**         a TEXT or BLOB value)^,
+**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
+**         constraint and the blob is being opened for read/write access)^,
+**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
+**         column zColumn is part of a [child key] definition and the blob is
+**         being opened for read/write access)^.
+** </ul>
+**
+** ^Unless it returns SQLITE_MISUSE, this function sets the
+** [database connection] error code and message accessible via
+** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
+**
+** A BLOB referenced by sqlite3_blob_open() may be read using the
+** [sqlite3_blob_read()] interface and modified by using
+** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
+** different row of the same table using the [sqlite3_blob_reopen()]
+** interface.  However, the column, table, or database of a [BLOB handle]
+** cannot be changed after the [BLOB handle] is opened.
+**
+** ^(If the row that a BLOB handle points to is modified by an
+** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
+** then the BLOB handle is marked as "expired".
+** This is true if any column of the row is changed, even a column
+** other than the one the BLOB handle is open on.)^
+** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
+** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
+** ^(Changes written into a BLOB prior to the BLOB expiring are not
+** rolled back by the expiration of the BLOB.  Such changes will eventually
+** commit if the transaction continues to completion.)^
+**
+** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
+** the opened blob.  ^The size of a blob may not be changed by this
+** interface.  Use the [UPDATE] SQL command to change the size of a
+** blob.
+**
+** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
+** and the built-in [zeroblob] SQL function may be used to create a
+** zero-filled blob to read or write using the incremental-blob interface.
+**
+** To avoid a resource leak, every open [BLOB handle] should eventually
+** be released by a call to [sqlite3_blob_close()].
+**
+** See also: [sqlite3_blob_close()],
+** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
+** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
+*/
+SQLITE_API int sqlite3_blob_open(
+  sqlite3*,
+  const char *zDb,
+  const char *zTable,
+  const char *zColumn,
+  sqlite3_int64 iRow,
+  int flags,
+  sqlite3_blob **ppBlob
+);
+
+/*
+** CAPI3REF: Move a BLOB Handle to a New Row
+** METHOD: sqlite3_blob
+**
+** ^This function is used to move an existing [BLOB handle] so that it points
+** to a different row of the same database table. ^The new row is identified
+** by the rowid value passed as the second argument. Only the row can be
+** changed. ^The database, table and column on which the blob handle is open
+** remain the same. Moving an existing [BLOB handle] to a new row is
+** faster than closing the existing handle and opening a new one.
+**
+** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
+** it must exist and there must be either a blob or text value stored in
+** the nominated column.)^ ^If the new row is not present in the table, or if
+** it does not contain a blob or text value, or if another error occurs, an
+** SQLite error code is returned and the blob handle is considered aborted.
+** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
+** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
+** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
+** always returns zero.
+**
+** ^This function sets the database handle error code and message.
+*/
+SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
+
+/*
+** CAPI3REF: Close A BLOB Handle
+** DESTRUCTOR: sqlite3_blob
+**
+** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
+** unconditionally.  Even if this routine returns an error code, the
+** handle is still closed.)^
+**
+** ^If the blob handle being closed was opened for read-write access, and if
+** the database is in auto-commit mode and there are no other open read-write
+** blob handles or active write statements, the current transaction is
+** committed. ^If an error occurs while committing the transaction, an error
+** code is returned and the transaction rolled back.
+**
+** Calling this function with an argument that is not a NULL pointer or an
+** open blob handle results in undefined behavior. ^Calling this routine
+** with a null pointer (such as would be returned by a failed call to
+** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
+** is passed a valid open blob handle, the values returned by the
+** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
+*/
+SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
+
+/*
+** CAPI3REF: Return The Size Of An Open BLOB
+** METHOD: sqlite3_blob
+**
+** ^Returns the size in bytes of the BLOB accessible via the
+** successfully opened [BLOB handle] in its only argument.  ^The
+** incremental blob I/O routines can only read or overwriting existing
+** blob content; they cannot change the size of a blob.
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+*/
+SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
+
+/*
+** CAPI3REF: Read Data From A BLOB Incrementally
+** METHOD: sqlite3_blob
+**
+** ^(This function is used to read data from an open [BLOB handle] into a
+** caller-supplied buffer. N bytes of data are copied into buffer Z
+** from the open BLOB, starting at offset iOffset.)^
+**
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
+** less than zero, [SQLITE_ERROR] is returned and no data is read.
+** ^The size of the blob (and hence the maximum value of N+iOffset)
+** can be determined using the [sqlite3_blob_bytes()] interface.
+**
+** ^An attempt to read from an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].
+**
+** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
+** Otherwise, an [error code] or an [extended error code] is returned.)^
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+**
+** See also: [sqlite3_blob_write()].
+*/
+SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
+
+/*
+** CAPI3REF: Write Data Into A BLOB Incrementally
+** METHOD: sqlite3_blob
+**
+** ^(This function is used to write data into an open [BLOB handle] from a
+** caller-supplied buffer. N bytes of data are copied from the buffer Z
+** into the open BLOB, starting at offset iOffset.)^
+**
+** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
+** Otherwise, an  [error code] or an [extended error code] is returned.)^
+** ^Unless SQLITE_MISUSE is returned, this function sets the
+** [database connection] error code and message accessible via
+** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
+**
+** ^If the [BLOB handle] passed as the first argument was not opened for
+** writing (the flags parameter to [sqlite3_blob_open()] was zero),
+** this function returns [SQLITE_READONLY].
+**
+** This function may only modify the contents of the BLOB; it is
+** not possible to increase the size of a BLOB using this API.
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is written. The size of the
+** BLOB (and hence the maximum value of N+iOffset) can be determined
+** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
+** than zero [SQLITE_ERROR] is returned and no data is written.
+**
+** ^An attempt to write to an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
+** before the [BLOB handle] expired are not rolled back by the
+** expiration of the handle, though of course those changes might
+** have been overwritten by the statement that expired the BLOB handle
+** or by other independent statements.
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+**
+** See also: [sqlite3_blob_read()].
+*/
+SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
+
+/*
+** CAPI3REF: Virtual File System Objects
+**
+** A virtual filesystem (VFS) is an [sqlite3_vfs] object
+** that SQLite uses to interact
+** with the underlying operating system.  Most SQLite builds come with a
+** single default VFS that is appropriate for the host computer.
+** New VFSes can be registered and existing VFSes can be unregistered.
+** The following interfaces are provided.
+**
+** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
+** ^Names are case sensitive.
+** ^Names are zero-terminated UTF-8 strings.
+** ^If there is no match, a NULL pointer is returned.
+** ^If zVfsName is NULL then the default VFS is returned.
+**
+** ^New VFSes are registered with sqlite3_vfs_register().
+** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
+** ^The same VFS can be registered multiple times without injury.
+** ^To make an existing VFS into the default VFS, register it again
+** with the makeDflt flag set.  If two different VFSes with the
+** same name are registered, the behavior is undefined.  If a
+** VFS is registered with a name that is NULL or an empty string,
+** then the behavior is undefined.
+**
+** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
+** ^(If the default VFS is unregistered, another VFS is chosen as
+** the default.  The choice for the new VFS is arbitrary.)^
+*/
+SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
+SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
+SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
+
+/*
+** CAPI3REF: Mutexes
+**
+** The SQLite core uses these routines for thread
+** synchronization. Though they are intended for internal
+** use by SQLite, code that links against SQLite is
+** permitted to use any of these routines.
+**
+** The SQLite source code contains multiple implementations
+** of these mutex routines.  An appropriate implementation
+** is selected automatically at compile-time.  The following
+** implementations are available in the SQLite core:
+**
+** <ul>
+** <li>   SQLITE_MUTEX_PTHREADS
+** <li>   SQLITE_MUTEX_W32
+** <li>   SQLITE_MUTEX_NOOP
+** </ul>
+**
+** The SQLITE_MUTEX_NOOP implementation is a set of routines
+** that does no real locking and is appropriate for use in
+** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
+** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
+** and Windows.
+**
+** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
+** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
+** implementation is included with the library. In this case the
+** application must supply a custom mutex implementation using the
+** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
+** before calling sqlite3_initialize() or any other public sqlite3_
+** function that calls sqlite3_initialize().
+**
+** ^The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
+** routine returns NULL if it is unable to allocate the requested
+** mutex.  The argument to sqlite3_mutex_alloc() must one of these
+** integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MAIN
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_OPEN
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
+** <li>  SQLITE_MUTEX_STATIC_APP1
+** <li>  SQLITE_MUTEX_STATIC_APP2
+** <li>  SQLITE_MUTEX_STATIC_APP3
+** <li>  SQLITE_MUTEX_STATIC_VFS1
+** <li>  SQLITE_MUTEX_STATIC_VFS2
+** <li>  SQLITE_MUTEX_STATIC_VFS3
+** </ul>
+**
+** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
+** cause sqlite3_mutex_alloc() to create
+** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
+** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
+** a pointer to a static preexisting mutex.  ^Nine static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  ^For the static
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+**
+** ^The sqlite3_mutex_free() routine deallocates a previously
+** allocated dynamic mutex.  Attempting to deallocate a static
+** mutex results in undefined behavior.
+**
+** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  ^If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
+** upon successful entry.  ^(Mutexes created using
+** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
+** In such cases, the
+** mutex must be exited an equal number of times before another thread
+** can enter.)^  If the same thread tries to enter any mutex other
+** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
+**
+** ^(Some systems (for example, Windows 95) do not support the operation
+** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
+** will always return SQLITE_BUSY. In most cases the SQLite core only uses
+** sqlite3_mutex_try() as an optimization, so this is acceptable
+** behavior. The exceptions are unix builds that set the
+** SQLITE_ENABLE_SETLK_TIMEOUT build option. In that case a working
+** sqlite3_mutex_try() is required.)^
+**
+** ^The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.   The behavior
+** is undefined if the mutex is not currently entered by the
+** calling thread or is not currently allocated.
+**
+** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(),
+** sqlite3_mutex_leave(), or sqlite3_mutex_free() is a NULL pointer,
+** then any of the four routines behaves as a no-op.
+**
+** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
+
+/*
+** CAPI3REF: Mutex Methods Object
+**
+** An instance of this structure defines the low-level routines
+** used to allocate and use mutexes.
+**
+** Usually, the default mutex implementations provided by SQLite are
+** sufficient, however the application has the option of substituting a custom
+** implementation for specialized deployments or systems for which SQLite
+** does not provide a suitable implementation. In this case, the application
+** creates and populates an instance of this structure to pass
+** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
+** Additionally, an instance of this structure can be used as an
+** output variable when querying the system for the current mutex
+** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
+**
+** ^The xMutexInit method defined by this structure is invoked as
+** part of system initialization by the sqlite3_initialize() function.
+** ^The xMutexInit routine is called by SQLite exactly once for each
+** effective call to [sqlite3_initialize()].
+**
+** ^The xMutexEnd method defined by this structure is invoked as
+** part of system shutdown by the sqlite3_shutdown() function. The
+** implementation of this method is expected to release all outstanding
+** resources obtained by the mutex methods implementation, especially
+** those obtained by the xMutexInit method.  ^The xMutexEnd()
+** interface is invoked exactly once for each call to [sqlite3_shutdown()].
+**
+** ^(The remaining seven methods defined by this structure (xMutexAlloc,
+** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
+** xMutexNotheld) implement the following interfaces (respectively):
+**
+** <ul>
+**   <li>  [sqlite3_mutex_alloc()] </li>
+**   <li>  [sqlite3_mutex_free()] </li>
+**   <li>  [sqlite3_mutex_enter()] </li>
+**   <li>  [sqlite3_mutex_try()] </li>
+**   <li>  [sqlite3_mutex_leave()] </li>
+**   <li>  [sqlite3_mutex_held()] </li>
+**   <li>  [sqlite3_mutex_notheld()] </li>
+** </ul>)^
+**
+** The only difference is that the public sqlite3_XXX functions enumerated
+** above silently ignore any invocations that pass a NULL pointer instead
+** of a valid mutex handle. The implementations of the methods defined
+** by this structure are not required to handle this case. The results
+** of passing a NULL pointer instead of a valid mutex handle are undefined
+** (i.e. it is acceptable to provide an implementation that segfaults if
+** it is passed a NULL pointer).
+**
+** The xMutexInit() method must be threadsafe.  It must be harmless to
+** invoke xMutexInit() multiple times within the same process and without
+** intervening calls to xMutexEnd().  Second and subsequent calls to
+** xMutexInit() must be no-ops.
+**
+** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
+** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
+** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
+** memory allocation for a fast or recursive mutex.
+**
+** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
+** called, but only if the prior call to xMutexInit returned SQLITE_OK.
+** If xMutexInit fails in any way, it is expected to clean up after itself
+** prior to returning.
+*/
+typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
+struct sqlite3_mutex_methods {
+  int (*xMutexInit)(void);
+  int (*xMutexEnd)(void);
+  sqlite3_mutex *(*xMutexAlloc)(int);
+  void (*xMutexFree)(sqlite3_mutex *);
+  void (*xMutexEnter)(sqlite3_mutex *);
+  int (*xMutexTry)(sqlite3_mutex *);
+  void (*xMutexLeave)(sqlite3_mutex *);
+  int (*xMutexHeld)(sqlite3_mutex *);
+  int (*xMutexNotheld)(sqlite3_mutex *);
+};
+
+/*
+** CAPI3REF: Mutex Verification Routines
+**
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
+** are intended for use inside assert() statements.  The SQLite core
+** never uses these routines except inside an assert() and applications
+** are advised to follow the lead of the core.  The SQLite core only
+** provides implementations for these routines when it is compiled
+** with the SQLITE_DEBUG flag.  External mutex implementations
+** are only required to provide these routines if SQLITE_DEBUG is
+** defined and if NDEBUG is not defined.
+**
+** These routines should return true if the mutex in their argument
+** is held or not held, respectively, by the calling thread.
+**
+** The implementation is not required to provide versions of these
+** routines that actually work. If the implementation does not provide working
+** versions of these routines, it should at least provide stubs that always
+** return true so that one does not get spurious assertion failures.
+**
+** If the argument to sqlite3_mutex_held() is a NULL pointer then
+** the routine should return 1.   This seems counter-intuitive since
+** clearly the mutex cannot be held if it does not exist.  But
+** the reason the mutex does not exist is because the build is not
+** using mutexes.  And we do not want the assert() containing the
+** call to sqlite3_mutex_held() to fail, so a non-zero return is
+** the appropriate thing to do.  The sqlite3_mutex_notheld()
+** interface should also return 1 when given a NULL pointer.
+*/
+#ifndef NDEBUG
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
+#endif
+
+/*
+** CAPI3REF: Mutex Types
+**
+** The [sqlite3_mutex_alloc()] interface takes a single argument
+** which is one of these integer constants.
+**
+** The set of static mutexes may change from one SQLite release to the
+** next.  Applications that override the built-in mutex logic must be
+** prepared to accommodate additional static mutexes.
+*/
+#define SQLITE_MUTEX_FAST             0
+#define SQLITE_MUTEX_RECURSIVE        1
+#define SQLITE_MUTEX_STATIC_MAIN      2
+#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
+#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
+#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
+#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
+#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
+#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
+#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
+#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
+#define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
+#define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
+#define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
+
+/* Legacy compatibility: */
+#define SQLITE_MUTEX_STATIC_MASTER    2
+
+
+/*
+** CAPI3REF: Retrieve the mutex for a database connection
+** METHOD: sqlite3
+**
+** ^This interface returns a pointer the [sqlite3_mutex] object that
+** serializes access to the [database connection] given in the argument
+** when the [threading mode] is Serialized.
+** ^If the [threading mode] is Single-thread or Multi-thread then this
+** routine returns a NULL pointer.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
+
+/*
+** CAPI3REF: Low-Level Control Of Database Files
+** METHOD: sqlite3
+** KEYWORDS: {file control}
+**
+** ^The [sqlite3_file_control()] interface makes a direct call to the
+** xFileControl method for the [sqlite3_io_methods] object associated
+** with a particular database identified by the second argument. ^The
+** name of the database is "main" for the main database or "temp" for the
+** TEMP database, or the name that appears after the AS keyword for
+** databases that are added using the [ATTACH] SQL command.
+** ^A NULL pointer can be used in place of "main" to refer to the
+** main database file.
+** ^The third and fourth parameters to this routine
+** are passed directly through to the second and third parameters of
+** the xFileControl method.  ^The return value of the xFileControl
+** method becomes the return value of this routine.
+**
+** A few opcodes for [sqlite3_file_control()] are handled directly
+** by the SQLite core and never invoke the
+** sqlite3_io_methods.xFileControl method.
+** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
+** a pointer to the underlying [sqlite3_file] object to be written into
+** the space pointed to by the 4th parameter.  The
+** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
+** the [sqlite3_file] object associated with the journal file instead of
+** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
+** a pointer to the underlying [sqlite3_vfs] object for the file.
+** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
+** from the pager.
+**
+** ^If the second parameter (zDbName) does not match the name of any
+** open database file, then SQLITE_ERROR is returned.  ^This error
+** code is not remembered and will not be recalled by [sqlite3_errcode()]
+** or [sqlite3_errmsg()].  The underlying xFileControl method might
+** also return SQLITE_ERROR.  There is no way to distinguish between
+** an incorrect zDbName and an SQLITE_ERROR return from the underlying
+** xFileControl method.
+**
+** See also: [file control opcodes]
+*/
+SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
+
+/*
+** CAPI3REF: Testing Interface
+**
+** ^The sqlite3_test_control() interface is used to read out internal
+** state of SQLite and to inject faults into SQLite for testing
+** purposes.  ^The first parameter is an operation code that determines
+** the number, meaning, and operation of all subsequent parameters.
+**
+** This interface is not for use by applications.  It exists solely
+** for verifying the correct operation of the SQLite library.  Depending
+** on how the SQLite library is compiled, this interface might not exist.
+**
+** The details of the operation codes, their meanings, the parameters
+** they take, and what they do are all subject to change without notice.
+** Unlike most of the SQLite API, this function is not guaranteed to
+** operate consistently from one release to the next.
+*/
+SQLITE_API int sqlite3_test_control(int op, ...);
+
+/*
+** CAPI3REF: Testing Interface Operation Codes
+**
+** These constants are the valid operation code parameters used
+** as the first argument to [sqlite3_test_control()].
+**
+** These parameters and their meanings are subject to change
+** without notice.  These values are for testing purposes only.
+** Applications should not use any of these parameters or the
+** [sqlite3_test_control()] interface.
+*/
+#define SQLITE_TESTCTRL_FIRST                    5
+#define SQLITE_TESTCTRL_PRNG_SAVE                5
+#define SQLITE_TESTCTRL_PRNG_RESTORE             6
+#define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
+#define SQLITE_TESTCTRL_FK_NO_ACTION             7
+#define SQLITE_TESTCTRL_BITVEC_TEST              8
+#define SQLITE_TESTCTRL_FAULT_INSTALL            9
+#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
+#define SQLITE_TESTCTRL_PENDING_BYTE            11
+#define SQLITE_TESTCTRL_ASSERT                  12
+#define SQLITE_TESTCTRL_ALWAYS                  13
+#define SQLITE_TESTCTRL_RESERVE                 14  /* NOT USED */
+#define SQLITE_TESTCTRL_JSON_SELFCHECK          14
+#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
+#define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
+#define SQLITE_TESTCTRL_GETOPT                  16
+#define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
+#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
+#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
+#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
+#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
+#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
+#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
+#define SQLITE_TESTCTRL_BYTEORDER               22
+#define SQLITE_TESTCTRL_ISINIT                  23
+#define SQLITE_TESTCTRL_SORTER_MMAP             24
+#define SQLITE_TESTCTRL_IMPOSTER                25
+#define SQLITE_TESTCTRL_PARSER_COVERAGE         26
+#define SQLITE_TESTCTRL_RESULT_INTREAL          27
+#define SQLITE_TESTCTRL_PRNG_SEED               28
+#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
+#define SQLITE_TESTCTRL_SEEK_COUNT              30
+#define SQLITE_TESTCTRL_TRACEFLAGS              31
+#define SQLITE_TESTCTRL_TUNE                    32
+#define SQLITE_TESTCTRL_LOGEST                  33
+#define SQLITE_TESTCTRL_USELONGDOUBLE           34  /* NOT USED */
+#define SQLITE_TESTCTRL_LAST                    34  /* Largest TESTCTRL */
+
+/*
+** CAPI3REF: SQL Keyword Checking
+**
+** These routines provide access to the set of SQL language keywords
+** recognized by SQLite.  Applications can uses these routines to determine
+** whether or not a specific identifier needs to be escaped (for example,
+** by enclosing in double-quotes) so as not to confuse the parser.
+**
+** The sqlite3_keyword_count() interface returns the number of distinct
+** keywords understood by SQLite.
+**
+** The sqlite3_keyword_name(N,Z,L) interface finds the 0-based N-th keyword and
+** makes *Z point to that keyword expressed as UTF8 and writes the number
+** of bytes in the keyword into *L.  The string that *Z points to is not
+** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
+** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
+** or L are NULL or invalid pointers then calls to
+** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
+**
+** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
+** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
+** if it is and zero if not.
+**
+** The parser used by SQLite is forgiving.  It is often possible to use
+** a keyword as an identifier as long as such use does not result in a
+** parsing ambiguity.  For example, the statement
+** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
+** creates a new table named "BEGIN" with three columns named
+** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
+** using keywords as identifiers.  Common techniques used to avoid keyword
+** name collisions include:
+** <ul>
+** <li> Put all identifier names inside double-quotes.  This is the official
+**      SQL way to escape identifier names.
+** <li> Put identifier names inside [...].  This is not standard SQL,
+**      but it is what SQL Server does and so lots of programmers use this
+**      technique.
+** <li> Begin every identifier with the letter "Z" as no SQL keywords start
+**      with "Z".
+** <li> Include a digit somewhere in every identifier name.
+** </ul>
+**
+** Note that the number of keywords understood by SQLite can depend on
+** compile-time options.  For example, "VACUUM" is not a keyword if
+** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
+** new keywords may be added to future releases of SQLite.
+*/
+SQLITE_API int sqlite3_keyword_count(void);
+SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
+SQLITE_API int sqlite3_keyword_check(const char*,int);
+
+/*
+** CAPI3REF: Dynamic String Object
+** KEYWORDS: {dynamic string}
+**
+** An instance of the sqlite3_str object contains a dynamically-sized
+** string under construction.
+**
+** The lifecycle of an sqlite3_str object is as follows:
+** <ol>
+** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
+** <li> ^Text is appended to the sqlite3_str object using various
+** methods, such as [sqlite3_str_appendf()].
+** <li> ^The sqlite3_str object is destroyed and the string it created
+** is returned using the [sqlite3_str_finish()] interface.
+** </ol>
+*/
+typedef struct sqlite3_str sqlite3_str;
+
+/*
+** CAPI3REF: Create A New Dynamic String Object
+** CONSTRUCTOR: sqlite3_str
+**
+** ^The [sqlite3_str_new(D)] interface allocates and initializes
+** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
+** [sqlite3_str_new()] must be freed by a subsequent call to
+** [sqlite3_str_finish(X)].
+**
+** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
+** valid [sqlite3_str] object, though in the event of an out-of-memory
+** error the returned object might be a special singleton that will
+** silently reject new text, always return SQLITE_NOMEM from
+** [sqlite3_str_errcode()], always return 0 for
+** [sqlite3_str_length()], and always return NULL from
+** [sqlite3_str_finish(X)].  It is always safe to use the value
+** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
+** to any of the other [sqlite3_str] methods.
+**
+** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
+** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
+** length of the string contained in the [sqlite3_str] object will be
+** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
+** of [SQLITE_MAX_LENGTH].
+*/
+SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
+
+/*
+** CAPI3REF: Finalize A Dynamic String
+** DESTRUCTOR: sqlite3_str
+**
+** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
+** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
+** that contains the constructed string.  The calling application should
+** pass the returned value to [sqlite3_free()] to avoid a memory leak.
+** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
+** errors were encountered during construction of the string.  ^The
+** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
+** string in [sqlite3_str] object X is zero bytes long.
+*/
+SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
+
+/*
+** CAPI3REF: Add Content To A Dynamic String
+** METHOD: sqlite3_str
+**
+** These interfaces add content to an sqlite3_str object previously obtained
+** from [sqlite3_str_new()].
+**
+** ^The [sqlite3_str_appendf(X,F,...)] and
+** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
+** functionality of SQLite to append formatted text onto the end of
+** [sqlite3_str] object X.
+**
+** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
+** onto the end of the [sqlite3_str] object X.  N must be non-negative.
+** S must contain at least N non-zero bytes of content.  To append a
+** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
+** method instead.
+**
+** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
+** zero-terminated string S onto the end of [sqlite3_str] object X.
+**
+** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
+** single-byte character C onto the end of [sqlite3_str] object X.
+** ^This method can be used, for example, to add whitespace indentation.
+**
+** ^The [sqlite3_str_reset(X)] method resets the string under construction
+** inside [sqlite3_str] object X back to zero bytes in length.
+**
+** These methods do not return a result code.  ^If an error occurs, that fact
+** is recorded in the [sqlite3_str] object and can be recovered by a
+** subsequent call to [sqlite3_str_errcode(X)].
+*/
+SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
+SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
+SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
+SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
+SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
+SQLITE_API void sqlite3_str_reset(sqlite3_str*);
+
+/*
+** CAPI3REF: Status Of A Dynamic String
+** METHOD: sqlite3_str
+**
+** These interfaces return the current status of an [sqlite3_str] object.
+**
+** ^If any prior errors have occurred while constructing the dynamic string
+** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
+** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
+** [SQLITE_NOMEM] following any out-of-memory error, or
+** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
+** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
+**
+** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
+** of the dynamic string under construction in [sqlite3_str] object X.
+** ^The length returned by [sqlite3_str_length(X)] does not include the
+** zero-termination byte.
+**
+** ^The [sqlite3_str_value(X)] method returns a pointer to the current
+** content of the dynamic string under construction in X.  The value
+** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
+** and might be freed or altered by any subsequent method on the same
+** [sqlite3_str] object.  Applications must not used the pointer returned
+** [sqlite3_str_value(X)] after any subsequent method call on the same
+** object.  ^Applications may change the content of the string returned
+** by [sqlite3_str_value(X)] as long as they do not write into any bytes
+** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
+** write any byte after any subsequent sqlite3_str method call.
+*/
+SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
+SQLITE_API int sqlite3_str_length(sqlite3_str*);
+SQLITE_API char *sqlite3_str_value(sqlite3_str*);
+
+/*
+** CAPI3REF: SQLite Runtime Status
+**
+** ^These interfaces are used to retrieve runtime status information
+** about the performance of SQLite, and optionally to reset various
+** highwater marks.  ^The first argument is an integer code for
+** the specific parameter to measure.  ^(Recognized integer codes
+** are of the form [status parameters | SQLITE_STATUS_...].)^
+** ^The current value of the parameter is returned into *pCurrent.
+** ^The highest recorded value is returned in *pHighwater.  ^If the
+** resetFlag is true, then the highest record value is reset after
+** *pHighwater is written.  ^(Some parameters do not record the highest
+** value.  For those parameters
+** nothing is written into *pHighwater and the resetFlag is ignored.)^
+** ^(Other parameters record only the highwater mark and not the current
+** value.  For these latter parameters nothing is written into *pCurrent.)^
+**
+** ^The sqlite3_status() and sqlite3_status64() routines return
+** SQLITE_OK on success and a non-zero [error code] on failure.
+**
+** If either the current value or the highwater mark is too large to
+** be represented by a 32-bit integer, then the values returned by
+** sqlite3_status() are undefined.
+**
+** See also: [sqlite3_db_status()]
+*/
+SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
+SQLITE_API int sqlite3_status64(
+  int op,
+  sqlite3_int64 *pCurrent,
+  sqlite3_int64 *pHighwater,
+  int resetFlag
+);
+
+
+/*
+** CAPI3REF: Status Parameters
+** KEYWORDS: {status parameters}
+**
+** These integer constants designate various run-time status parameters
+** that can be returned by [sqlite3_status()].
+**
+** <dl>
+** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
+** <dd>This parameter is the current amount of memory checked out
+** using [sqlite3_malloc()], either directly or indirectly.  The
+** figure includes calls made to [sqlite3_malloc()] by the application
+** and internal memory usage by the SQLite library.  Auxiliary page-cache
+** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
+** this parameter.  The amount returned is the sum of the allocation
+** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
+**
+** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
+** <dd>This parameter records the largest memory allocation request
+** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
+** internal equivalents).  Only the value returned in the
+** *pHighwater parameter to [sqlite3_status()] is of interest.
+** The value written into the *pCurrent parameter is undefined.</dd>)^
+**
+** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
+** <dd>This parameter records the number of separate memory allocations
+** currently checked out.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
+** <dd>This parameter returns the number of pages used out of the
+** [pagecache memory allocator] that was configured using
+** [SQLITE_CONFIG_PAGECACHE].  The
+** value returned is in pages, not in bytes.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
+** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
+** <dd>This parameter returns the number of bytes of page cache
+** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
+** buffer and where forced to overflow to [sqlite3_malloc()].  The
+** returned value includes allocations that overflowed because they
+** where too large (they were larger than the "sz" parameter to
+** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
+** no space was left in the page cache.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
+** <dd>This parameter records the largest memory allocation request
+** handed to the [pagecache memory allocator].  Only the value returned in the
+** *pHighwater parameter to [sqlite3_status()] is of interest.
+** The value written into the *pCurrent parameter is undefined.</dd>)^
+**
+** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
+** <dd>The *pHighwater parameter records the deepest parser stack.
+** The *pCurrent value is undefined.  The *pHighwater value is only
+** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
+** </dl>
+**
+** New status parameters may be added from time to time.
+*/
+#define SQLITE_STATUS_MEMORY_USED          0
+#define SQLITE_STATUS_PAGECACHE_USED       1
+#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
+#define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
+#define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
+#define SQLITE_STATUS_MALLOC_SIZE          5
+#define SQLITE_STATUS_PARSER_STACK         6
+#define SQLITE_STATUS_PAGECACHE_SIZE       7
+#define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
+#define SQLITE_STATUS_MALLOC_COUNT         9
+
+/*
+** CAPI3REF: Database Connection Status
+** METHOD: sqlite3
+**
+** ^This interface is used to retrieve runtime status information
+** about a single [database connection].  ^The first argument is the
+** database connection object to be interrogated.  ^The second argument
+** is an integer constant, taken from the set of
+** [SQLITE_DBSTATUS options], that
+** determines the parameter to interrogate.  The set of
+** [SQLITE_DBSTATUS options] is likely
+** to grow in future releases of SQLite.
+**
+** ^The current value of the requested parameter is written into *pCur
+** and the highest instantaneous value is written into *pHiwtr.  ^If
+** the resetFlg is true, then the highest instantaneous value is
+** reset back down to the current value.
+**
+** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
+** non-zero [error code] on failure.
+**
+** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
+*/
+SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
+
+/*
+** CAPI3REF: Status Parameters for database connections
+** KEYWORDS: {SQLITE_DBSTATUS options}
+**
+** These constants are the available integer "verbs" that can be passed as
+** the second argument to the [sqlite3_db_status()] interface.
+**
+** New verbs may be added in future releases of SQLite. Existing verbs
+** might be discontinued. Applications should check the return code from
+** [sqlite3_db_status()] to make sure that the call worked.
+** The [sqlite3_db_status()] interface will return a non-zero error code
+** if a discontinued or unsupported verb is invoked.
+**
+** <dl>
+** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
+** <dd>This parameter returns the number of lookaside memory slots currently
+** checked out.</dd>)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
+** <dd>This parameter returns the number of malloc attempts that were
+** satisfied using lookaside memory. Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to the amount of
+** memory requested being larger than the lookaside slot size.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to all lookaside
+** memory already being in use.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** memory used by all pager caches associated with the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
+** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
+** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
+** pager cache is shared between two or more connections the bytes of heap
+** memory used by that pager cache is divided evenly between the attached
+** connections.)^  In other words, if none of the pager caches associated
+** with the database connection are shared, this request returns the same
+** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
+** shared, the value returned by this call will be smaller than that returned
+** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
+** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
+**
+** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** memory used to store the schema for all databases associated
+** with the connection - main, temp, and any [ATTACH]-ed databases.)^
+** ^The full amount of memory used by the schemas is reported, even if the
+** schema memory is shared with other database connections due to
+** [shared cache mode] being enabled.
+** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** and lookaside memory used by all prepared statements associated with
+** the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
+** <dd>This parameter returns the number of pager cache hits that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
+** <dd>This parameter returns the number of pager cache misses that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk. Specifically, the number of pages written to the
+** wal file in wal mode databases, or the number of pages written to the
+** database file in rollback mode databases. Any pages written as part of
+** transaction rollback or database recovery operations are not included.
+** If an IO or other error occurs while writing a page to disk, the effect
+** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
+** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk in the middle of a transaction due to the page
+** cache overflowing. Transactions are more efficient if they are written
+** to disk all at once. When pages spill mid-transaction, that introduces
+** additional overhead. This parameter can be used help identify
+** inefficiencies that can be resolved by increasing the cache size.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
+** <dd>This parameter returns zero for the current value if and only if
+** all foreign key constraints (deferred or immediate) have been
+** resolved.)^  ^The highwater mark is always 0.
+** </dd>
+** </dl>
+*/
+#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
+#define SQLITE_DBSTATUS_CACHE_USED           1
+#define SQLITE_DBSTATUS_SCHEMA_USED          2
+#define SQLITE_DBSTATUS_STMT_USED            3
+#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
+#define SQLITE_DBSTATUS_CACHE_HIT            7
+#define SQLITE_DBSTATUS_CACHE_MISS           8
+#define SQLITE_DBSTATUS_CACHE_WRITE          9
+#define SQLITE_DBSTATUS_DEFERRED_FKS        10
+#define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
+#define SQLITE_DBSTATUS_CACHE_SPILL         12
+#define SQLITE_DBSTATUS_MAX                 12   /* Largest defined DBSTATUS */
+
+
+/*
+** CAPI3REF: Prepared Statement Status
+** METHOD: sqlite3_stmt
+**
+** ^(Each prepared statement maintains various
+** [SQLITE_STMTSTATUS counters] that measure the number
+** of times it has performed specific operations.)^  These counters can
+** be used to monitor the performance characteristics of the prepared
+** statements.  For example, if the number of table steps greatly exceeds
+** the number of table searches or result rows, that would tend to indicate
+** that the prepared statement is using a full table scan rather than
+** an index.
+**
+** ^(This interface is used to retrieve and reset counter values from
+** a [prepared statement].  The first argument is the prepared statement
+** object to be interrogated.  The second argument
+** is an integer code for a specific [SQLITE_STMTSTATUS counter]
+** to be interrogated.)^
+** ^The current value of the requested counter is returned.
+** ^If the resetFlg is true, then the counter is reset to zero after this
+** interface call returns.
+**
+** See also: [sqlite3_status()] and [sqlite3_db_status()].
+*/
+SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
+
+/*
+** CAPI3REF: Status Parameters for prepared statements
+** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
+**
+** These preprocessor macros define integer codes that name counter
+** values associated with the [sqlite3_stmt_status()] interface.
+** The meanings of the various counters are as follows:
+**
+** <dl>
+** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
+** <dd>^This is the number of times that SQLite has stepped forward in
+** a table as part of a full table scan.  Large numbers for this counter
+** may indicate opportunities for performance improvement through
+** careful use of indices.</dd>
+**
+** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
+** <dd>^This is the number of sort operations that have occurred.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance through careful use of indices.</dd>
+**
+** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
+** <dd>^This is the number of rows inserted into transient indices that
+** were created automatically in order to help joins run faster.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance by adding permanent indices that do not
+** need to be reinitialized each time the statement is run.</dd>
+**
+** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
+** <dd>^This is the number of virtual machine operations executed
+** by the prepared statement if that number is less than or equal
+** to 2147483647.  The number of virtual machine operations can be
+** used as a proxy for the total work done by the prepared statement.
+** If the number of virtual machine operations exceeds 2147483647
+** then the value returned by this statement status code is undefined.
+**
+** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
+** <dd>^This is the number of times that the prepare statement has been
+** automatically regenerated due to schema changes or changes to
+** [bound parameters] that might affect the query plan.
+**
+** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
+** <dd>^This is the number of times that the prepared statement has
+** been run.  A single "run" for the purposes of this counter is one
+** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
+** The counter is incremented on the first [sqlite3_step()] call of each
+** cycle.
+**
+** [[SQLITE_STMTSTATUS_FILTER_MISS]]
+** [[SQLITE_STMTSTATUS_FILTER HIT]]
+** <dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
+** SQLITE_STMTSTATUS_FILTER_MISS</dt>
+** <dd>^SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
+** step was bypassed because a Bloom filter returned not-found.  The
+** corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
+** times that the Bloom filter returned a find, and thus the join step
+** had to be processed as normal.
+**
+** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
+** <dd>^This is the approximate number of bytes of heap memory
+** used to store the prepared statement.  ^This value is not actually
+** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
+** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
+** </dd>
+** </dl>
+*/
+#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
+#define SQLITE_STMTSTATUS_SORT              2
+#define SQLITE_STMTSTATUS_AUTOINDEX         3
+#define SQLITE_STMTSTATUS_VM_STEP           4
+#define SQLITE_STMTSTATUS_REPREPARE         5
+#define SQLITE_STMTSTATUS_RUN               6
+#define SQLITE_STMTSTATUS_FILTER_MISS       7
+#define SQLITE_STMTSTATUS_FILTER_HIT        8
+#define SQLITE_STMTSTATUS_MEMUSED           99
+
+/*
+** CAPI3REF: Custom Page Cache Object
+**
+** The sqlite3_pcache type is opaque.  It is implemented by
+** the pluggable module.  The SQLite core has no knowledge of
+** its size or internal structure and never deals with the
+** sqlite3_pcache object except by holding and passing pointers
+** to the object.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache sqlite3_pcache;
+
+/*
+** CAPI3REF: Custom Page Cache Object
+**
+** The sqlite3_pcache_page object represents a single page in the
+** page cache.  The page cache will allocate instances of this
+** object.  Various methods of the page cache use pointers to instances
+** of this object as parameters or as their return value.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache_page sqlite3_pcache_page;
+struct sqlite3_pcache_page {
+  void *pBuf;        /* The content of the page */
+  void *pExtra;      /* Extra information associated with the page */
+};
+
+/*
+** CAPI3REF: Application Defined Page Cache.
+** KEYWORDS: {page cache}
+**
+** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
+** register an alternative page cache implementation by passing in an
+** instance of the sqlite3_pcache_methods2 structure.)^
+** In many applications, most of the heap memory allocated by
+** SQLite is used for the page cache.
+** By implementing a
+** custom page cache using this API, an application can better control
+** the amount of memory consumed by SQLite, the way in which
+** that memory is allocated and released, and the policies used to
+** determine exactly which parts of a database file are cached and for
+** how long.
+**
+** The alternative page cache mechanism is an
+** extreme measure that is only needed by the most demanding applications.
+** The built-in page cache is recommended for most uses.
+**
+** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
+** internal buffer by SQLite within the call to [sqlite3_config].  Hence
+** the application may discard the parameter after the call to
+** [sqlite3_config()] returns.)^
+**
+** [[the xInit() page cache method]]
+** ^(The xInit() method is called once for each effective
+** call to [sqlite3_initialize()])^
+** (usually only once during the lifetime of the process). ^(The xInit()
+** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
+** The intent of the xInit() method is to set up global data structures
+** required by the custom page cache implementation.
+** ^(If the xInit() method is NULL, then the
+** built-in default page cache is used instead of the application defined
+** page cache.)^
+**
+** [[the xShutdown() page cache method]]
+** ^The xShutdown() method is called by [sqlite3_shutdown()].
+** It can be used to clean up
+** any outstanding resources before process shutdown, if required.
+** ^The xShutdown() method may be NULL.
+**
+** ^SQLite automatically serializes calls to the xInit method,
+** so the xInit method need not be threadsafe.  ^The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  All other methods must be threadsafe
+** in multithreaded applications.
+**
+** ^SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+**
+** [[the xCreate() page cache methods]]
+** ^SQLite invokes the xCreate() method to construct a new cache instance.
+** SQLite will typically create one cache instance for each open database file,
+** though this is not guaranteed. ^The
+** first parameter, szPage, is the size in bytes of the pages that must
+** be allocated by the cache.  ^szPage will always a power of two.  ^The
+** second parameter szExtra is a number of bytes of extra storage
+** associated with each page cache entry.  ^The szExtra parameter will
+** a number less than 250.  SQLite will use the
+** extra szExtra bytes on each page to store metadata about the underlying
+** database page on disk.  The value passed into szExtra depends
+** on the SQLite version, the target platform, and how SQLite was compiled.
+** ^The third argument to xCreate(), bPurgeable, is true if the cache being
+** created will be used to cache database pages of a file stored on disk, or
+** false if it is used for an in-memory database. The cache implementation
+** does not have to do anything special based with the value of bPurgeable;
+** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
+** never invoke xUnpin() except to deliberately delete a page.
+** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
+** false will always have the "discard" flag set to true.
+** ^Hence, a cache created with bPurgeable false will
+** never contain any unpinned pages.
+**
+** [[the xCachesize() page cache method]]
+** ^(The xCachesize() method may be called at any time by SQLite to set the
+** suggested maximum cache-size (number of pages stored by) the cache
+** instance passed as the first argument. This is the value configured using
+** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
+** parameter, the implementation is not required to do anything with this
+** value; it is advisory only.
+**
+** [[the xPagecount() page cache methods]]
+** The xPagecount() method must return the number of pages currently
+** stored in the cache, both pinned and unpinned.
+**
+** [[the xFetch() page cache methods]]
+** The xFetch() method locates a page in the cache and returns a pointer to
+** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
+** The pBuf element of the returned sqlite3_pcache_page object will be a
+** pointer to a buffer of szPage bytes used to store the content of a
+** single database page.  The pExtra element of sqlite3_pcache_page will be
+** a pointer to the szExtra bytes of extra storage that SQLite has requested
+** for each entry in the page cache.
+**
+** The page to be fetched is determined by the key. ^The minimum key value
+** is 1.  After it has been retrieved using xFetch, the page is considered
+** to be "pinned".
+**
+** If the requested page is already in the page cache, then the page cache
+** implementation must return a pointer to the page buffer with its content
+** intact.  If the requested page is not already in the cache, then the
+** cache implementation should use the value of the createFlag
+** parameter to help it determined what action to take:
+**
+** <table border=1 width=85% align=center>
+** <tr><th> createFlag <th> Behavior when page is not already in cache
+** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
+** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
+**                 Otherwise return NULL.
+** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
+**                 NULL if allocating a new page is effectively impossible.
+** </table>
+**
+** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
+** will only use a createFlag of 2 after a prior call with a createFlag of 1
+** failed.)^  In between the xFetch() calls, SQLite may
+** attempt to unpin one or more cache pages by spilling the content of
+** pinned pages to disk and synching the operating system disk cache.
+**
+** [[the xUnpin() page cache method]]
+** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
+** as its second argument.  If the third parameter, discard, is non-zero,
+** then the page must be evicted from the cache.
+** ^If the discard parameter is
+** zero, then the page may be discarded or retained at the discretion of
+** page cache implementation. ^The page cache implementation
+** may choose to evict unpinned pages at any time.
+**
+** The cache must not perform any reference counting. A single
+** call to xUnpin() unpins the page regardless of the number of prior calls
+** to xFetch().
+**
+** [[the xRekey() page cache methods]]
+** The xRekey() method is used to change the key value associated with the
+** page passed as the second argument. If the cache
+** previously contains an entry associated with newKey, it must be
+** discarded. ^Any prior cache entry associated with newKey is guaranteed not
+** to be pinned.
+**
+** When SQLite calls the xTruncate() method, the cache must discard all
+** existing cache entries with page numbers (keys) greater than or equal
+** to the value of the iLimit parameter passed to xTruncate(). If any
+** of these pages are pinned, they are implicitly unpinned, meaning that
+** they can be safely discarded.
+**
+** [[the xDestroy() page cache method]]
+** ^The xDestroy() method is used to delete a cache allocated by xCreate().
+** All resources associated with the specified cache should be freed. ^After
+** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
+** handle invalid, and will not use it with any other sqlite3_pcache_methods2
+** functions.
+**
+** [[the xShrink() page cache method]]
+** ^SQLite invokes the xShrink() method when it wants the page cache to
+** free up as much of heap memory as possible.  The page cache implementation
+** is not obligated to free any memory, but well-behaved implementations should
+** do their best.
+*/
+typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
+struct sqlite3_pcache_methods2 {
+  int iVersion;
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
+  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
+      unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+  void (*xShrink)(sqlite3_pcache*);
+};
+
+/*
+** This is the obsolete pcache_methods object that has now been replaced
+** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
+** retained in the header file for backwards compatibility only.
+*/
+typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
+struct sqlite3_pcache_methods {
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
+  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+};
+
+
+/*
+** CAPI3REF: Online Backup Object
+**
+** The sqlite3_backup object records state information about an ongoing
+** online backup operation.  ^The sqlite3_backup object is created by
+** a call to [sqlite3_backup_init()] and is destroyed by a call to
+** [sqlite3_backup_finish()].
+**
+** See Also: [Using the SQLite Online Backup API]
+*/
+typedef struct sqlite3_backup sqlite3_backup;
+
+/*
+** CAPI3REF: Online Backup API.
+**
+** The backup API copies the content of one database into another.
+** It is useful either for creating backups of databases or
+** for copying in-memory databases to or from persistent files.
+**
+** See Also: [Using the SQLite Online Backup API]
+**
+** ^SQLite holds a write transaction open on the destination database file
+** for the duration of the backup operation.
+** ^The source database is read-locked only while it is being read;
+** it is not locked continuously for the entire backup operation.
+** ^Thus, the backup may be performed on a live source database without
+** preventing other database connections from
+** reading or writing to the source database while the backup is underway.
+**
+** ^(To perform a backup operation:
+**   <ol>
+**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
+**         backup,
+**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
+**         the data between the two databases, and finally
+**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
+**         associated with the backup operation.
+**   </ol>)^
+** There should be exactly one call to sqlite3_backup_finish() for each
+** successful call to sqlite3_backup_init().
+**
+** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
+**
+** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
+** [database connection] associated with the destination database
+** and the database name, respectively.
+** ^The database name is "main" for the main database, "temp" for the
+** temporary database, or the name specified after the AS keyword in
+** an [ATTACH] statement for an attached database.
+** ^The S and M arguments passed to
+** sqlite3_backup_init(D,N,S,M) identify the [database connection]
+** and database name of the source database, respectively.
+** ^The source and destination [database connections] (parameters S and D)
+** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
+** an error.
+**
+** ^A call to sqlite3_backup_init() will fail, returning NULL, if
+** there is already a read or read-write transaction open on the
+** destination database.
+**
+** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
+** returned and an error code and error message are stored in the
+** destination [database connection] D.
+** ^The error code and message for the failed call to sqlite3_backup_init()
+** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
+** [sqlite3_errmsg16()] functions.
+** ^A successful call to sqlite3_backup_init() returns a pointer to an
+** [sqlite3_backup] object.
+** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
+** sqlite3_backup_finish() functions to perform the specified backup
+** operation.
+**
+** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
+**
+** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
+** the source and destination databases specified by [sqlite3_backup] object B.
+** ^If N is negative, all remaining source pages are copied.
+** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
+** are still more pages to be copied, then the function returns [SQLITE_OK].
+** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
+** from source to destination, then it returns [SQLITE_DONE].
+** ^If an error occurs while running sqlite3_backup_step(B,N),
+** then an [error code] is returned. ^As well as [SQLITE_OK] and
+** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
+** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
+**
+** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
+** <ol>
+** <li> the destination database was opened read-only, or
+** <li> the destination database is using write-ahead-log journaling
+** and the destination and source page sizes differ, or
+** <li> the destination database is an in-memory database and the
+** destination and source page sizes differ.
+** </ol>)^
+**
+** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
+** the [sqlite3_busy_handler | busy-handler function]
+** is invoked (if one is specified). ^If the
+** busy-handler returns non-zero before the lock is available, then
+** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
+** sqlite3_backup_step() can be retried later. ^If the source
+** [database connection]
+** is being used to write to the source database when sqlite3_backup_step()
+** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
+** case the call to sqlite3_backup_step() can be retried later on. ^(If
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
+** [SQLITE_READONLY] is returned, then
+** there is no point in retrying the call to sqlite3_backup_step(). These
+** errors are considered fatal.)^  The application must accept
+** that the backup operation has failed and pass the backup operation handle
+** to the sqlite3_backup_finish() to release associated resources.
+**
+** ^The first call to sqlite3_backup_step() obtains an exclusive lock
+** on the destination file. ^The exclusive lock is not released until either
+** sqlite3_backup_finish() is called or the backup operation is complete
+** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
+** sqlite3_backup_step() obtains a [shared lock] on the source database that
+** lasts for the duration of the sqlite3_backup_step() call.
+** ^Because the source database is not locked between calls to
+** sqlite3_backup_step(), the source database may be modified mid-way
+** through the backup process.  ^If the source database is modified by an
+** external process or via a database connection other than the one being
+** used by the backup operation, then the backup will be automatically
+** restarted by the next call to sqlite3_backup_step(). ^If the source
+** database is modified by the using the same database connection as is used
+** by the backup operation, then the backup database is automatically
+** updated at the same time.
+**
+** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
+**
+** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
+** application wishes to abandon the backup operation, the application
+** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
+** ^The sqlite3_backup_finish() interfaces releases all
+** resources associated with the [sqlite3_backup] object.
+** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
+** active write-transaction on the destination database is rolled back.
+** The [sqlite3_backup] object is invalid
+** and may not be used following a call to sqlite3_backup_finish().
+**
+** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
+** sqlite3_backup_step() errors occurred, regardless or whether or not
+** sqlite3_backup_step() completed.
+** ^If an out-of-memory condition or IO error occurred during any prior
+** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
+** sqlite3_backup_finish() returns the corresponding [error code].
+**
+** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
+** is not a permanent error and does not affect the return value of
+** sqlite3_backup_finish().
+**
+** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
+** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
+**
+** ^The sqlite3_backup_remaining() routine returns the number of pages still
+** to be backed up at the conclusion of the most recent sqlite3_backup_step().
+** ^The sqlite3_backup_pagecount() routine returns the total number of pages
+** in the source database at the conclusion of the most recent
+** sqlite3_backup_step().
+** ^(The values returned by these functions are only updated by
+** sqlite3_backup_step(). If the source database is modified in a way that
+** changes the size of the source database or the number of pages remaining,
+** those changes are not reflected in the output of sqlite3_backup_pagecount()
+** and sqlite3_backup_remaining() until after the next
+** sqlite3_backup_step().)^
+**
+** <b>Concurrent Usage of Database Handles</b>
+**
+** ^The source [database connection] may be used by the application for other
+** purposes while a backup operation is underway or being initialized.
+** ^If SQLite is compiled and configured to support threadsafe database
+** connections, then the source database connection may be used concurrently
+** from within other threads.
+**
+** However, the application must guarantee that the destination
+** [database connection] is not passed to any other API (by any thread) after
+** sqlite3_backup_init() is called and before the corresponding call to
+** sqlite3_backup_finish().  SQLite does not currently check to see
+** if the application incorrectly accesses the destination [database connection]
+** and so no error code is reported, but the operations may malfunction
+** nevertheless.  Use of the destination database connection while a
+** backup is in progress might also cause a mutex deadlock.
+**
+** If running in [shared cache mode], the application must
+** guarantee that the shared cache used by the destination database
+** is not accessed while the backup is running. In practice this means
+** that the application must guarantee that the disk file being
+** backed up to is not accessed by any connection within the process,
+** not just the specific connection that was passed to sqlite3_backup_init().
+**
+** The [sqlite3_backup] object itself is partially threadsafe. Multiple
+** threads may safely make multiple concurrent calls to sqlite3_backup_step().
+** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
+** APIs are not strictly speaking threadsafe. If they are invoked at the
+** same time as another thread is invoking sqlite3_backup_step() it is
+** possible that they return invalid values.
+**
+** <b>Alternatives To Using The Backup API</b>
+**
+** Other techniques for safely creating a consistent backup of an SQLite
+** database include:
+**
+** <ul>
+** <li> The [VACUUM INTO] command.
+** <li> The [sqlite3_rsync] utility program.
+** </ul>
+*/
+SQLITE_API sqlite3_backup *sqlite3_backup_init(
+  sqlite3 *pDest,                        /* Destination database handle */
+  const char *zDestName,                 /* Destination database name */
+  sqlite3 *pSource,                      /* Source database handle */
+  const char *zSourceName                /* Source database name */
+);
+SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
+SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
+
+/*
+** CAPI3REF: Unlock Notification
+** METHOD: sqlite3
+**
+** ^When running in shared-cache mode, a database operation may fail with
+** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
+** individual tables within the shared-cache cannot be obtained. See
+** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
+** ^This API may be used to register a callback that SQLite will invoke
+** when the connection currently holding the required lock relinquishes it.
+** ^This API is only available if the library was compiled with the
+** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
+**
+** See Also: [Using the SQLite Unlock Notification Feature].
+**
+** ^Shared-cache locks are released when a database connection concludes
+** its current transaction, either by committing it or rolling it back.
+**
+** ^When a connection (known as the blocked connection) fails to obtain a
+** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
+** identity of the database connection (the blocking connection) that
+** has locked the required resource is stored internally. ^After an
+** application receives an SQLITE_LOCKED error, it may call the
+** sqlite3_unlock_notify() method with the blocked connection handle as
+** the first argument to register for a callback that will be invoked
+** when the blocking connections current transaction is concluded. ^The
+** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
+** call that concludes the blocking connection's transaction.
+**
+** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
+** there is a chance that the blocking connection will have already
+** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
+** If this happens, then the specified callback is invoked immediately,
+** from within the call to sqlite3_unlock_notify().)^
+**
+** ^If the blocked connection is attempting to obtain a write-lock on a
+** shared-cache table, and more than one other connection currently holds
+** a read-lock on the same table, then SQLite arbitrarily selects one of
+** the other connections to use as the blocking connection.
+**
+** ^(There may be at most one unlock-notify callback registered by a
+** blocked connection. If sqlite3_unlock_notify() is called when the
+** blocked connection already has a registered unlock-notify callback,
+** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
+** called with a NULL pointer as its second argument, then any existing
+** unlock-notify callback is canceled. ^The blocked connections
+** unlock-notify callback may also be canceled by closing the blocked
+** connection using [sqlite3_close()].
+**
+** The unlock-notify callback is not reentrant. If an application invokes
+** any sqlite3_xxx API functions from within an unlock-notify callback, a
+** crash or deadlock may be the result.
+**
+** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
+** returns SQLITE_OK.
+**
+** <b>Callback Invocation Details</b>
+**
+** When an unlock-notify callback is registered, the application provides a
+** single void* pointer that is passed to the callback when it is invoked.
+** However, the signature of the callback function allows SQLite to pass
+** it an array of void* context pointers. The first argument passed to
+** an unlock-notify callback is a pointer to an array of void* pointers,
+** and the second is the number of entries in the array.
+**
+** When a blocking connection's transaction is concluded, there may be
+** more than one blocked connection that has registered for an unlock-notify
+** callback. ^If two or more such blocked connections have specified the
+** same callback function, then instead of invoking the callback function
+** multiple times, it is invoked once with the set of void* context pointers
+** specified by the blocked connections bundled together into an array.
+** This gives the application an opportunity to prioritize any actions
+** related to the set of unblocked database connections.
+**
+** <b>Deadlock Detection</b>
+**
+** Assuming that after registering for an unlock-notify callback a
+** database waits for the callback to be issued before taking any further
+** action (a reasonable assumption), then using this API may cause the
+** application to deadlock. For example, if connection X is waiting for
+** connection Y's transaction to be concluded, and similarly connection
+** Y is waiting on connection X's transaction, then neither connection
+** will proceed and the system may remain deadlocked indefinitely.
+**
+** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
+** detection. ^If a given call to sqlite3_unlock_notify() would put the
+** system in a deadlocked state, then SQLITE_LOCKED is returned and no
+** unlock-notify callback is registered. The system is said to be in
+** a deadlocked state if connection A has registered for an unlock-notify
+** callback on the conclusion of connection B's transaction, and connection
+** B has itself registered for an unlock-notify callback when connection
+** A's transaction is concluded. ^Indirect deadlock is also detected, so
+** the system is also considered to be deadlocked if connection B has
+** registered for an unlock-notify callback on the conclusion of connection
+** C's transaction, where connection C is waiting on connection A. ^Any
+** number of levels of indirection are allowed.
+**
+** <b>The "DROP TABLE" Exception</b>
+**
+** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
+** always appropriate to call sqlite3_unlock_notify(). There is however,
+** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
+** SQLite checks if there are any currently executing SELECT statements
+** that belong to the same connection. If there are, SQLITE_LOCKED is
+** returned. In this case there is no "blocking connection", so invoking
+** sqlite3_unlock_notify() results in the unlock-notify callback being
+** invoked immediately. If the application then re-attempts the "DROP TABLE"
+** or "DROP INDEX" query, an infinite loop might be the result.
+**
+** One way around this problem is to check the extended error code returned
+** by an sqlite3_step() call. ^(If there is a blocking connection, then the
+** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
+** the special "DROP TABLE/INDEX" case, the extended error code is just
+** SQLITE_LOCKED.)^
+*/
+SQLITE_API int sqlite3_unlock_notify(
+  sqlite3 *pBlocked,                          /* Waiting connection */
+  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
+  void *pNotifyArg                            /* Argument to pass to xNotify */
+);
+
+
+/*
+** CAPI3REF: String Comparison
+**
+** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
+** and extensions to compare the contents of two buffers containing UTF-8
+** strings in a case-independent fashion, using the same definition of "case
+** independence" that SQLite uses internally when comparing identifiers.
+*/
+SQLITE_API int sqlite3_stricmp(const char *, const char *);
+SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
+
+/*
+** CAPI3REF: String Globbing
+*
+** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
+** string X matches the [GLOB] pattern P.
+** ^The definition of [GLOB] pattern matching used in
+** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
+** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
+** is case sensitive.
+**
+** Note that this routine returns zero on a match and non-zero if the strings
+** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
+**
+** See also: [sqlite3_strlike()].
+*/
+SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
+
+/*
+** CAPI3REF: String LIKE Matching
+*
+** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
+** string X matches the [LIKE] pattern P with escape character E.
+** ^The definition of [LIKE] pattern matching used in
+** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
+** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
+** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
+** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
+** insensitive - equivalent upper and lower case ASCII characters match
+** one another.
+**
+** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
+** only ASCII characters are case folded.
+**
+** Note that this routine returns zero on a match and non-zero if the strings
+** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
+**
+** See also: [sqlite3_strglob()].
+*/
+SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
+
+/*
+** CAPI3REF: Error Logging Interface
+**
+** ^The [sqlite3_log()] interface writes a message into the [error log]
+** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
+** ^If logging is enabled, the zFormat string and subsequent arguments are
+** used with [sqlite3_snprintf()] to generate the final output string.
+**
+** The sqlite3_log() interface is intended for use by extensions such as
+** virtual tables, collating functions, and SQL functions.  While there is
+** nothing to prevent an application from calling sqlite3_log(), doing so
+** is considered bad form.
+**
+** The zFormat string must not be NULL.
+**
+** To avoid deadlocks and other threading problems, the sqlite3_log() routine
+** will not use dynamically allocated memory.  The log message is stored in
+** a fixed-length buffer on the stack.  If the log message is longer than
+** a few hundred characters, it will be truncated to the length of the
+** buffer.
+*/
+SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
+
+/*
+** CAPI3REF: Write-Ahead Log Commit Hook
+** METHOD: sqlite3
+**
+** ^The [sqlite3_wal_hook()] function is used to register a callback that
+** is invoked each time data is committed to a database in wal mode.
+**
+** ^(The callback is invoked by SQLite after the commit has taken place and
+** the associated write-lock on the database released)^, so the implementation
+** may read, write or [checkpoint] the database as required.
+**
+** ^The first parameter passed to the callback function when it is invoked
+** is a copy of the third parameter passed to sqlite3_wal_hook() when
+** registering the callback. ^The second is a copy of the database handle.
+** ^The third parameter is the name of the database that was written to -
+** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
+** is the number of pages currently in the write-ahead log file,
+** including those that were just committed.
+**
+** The callback function should normally return [SQLITE_OK].  ^If an error
+** code is returned, that error will propagate back up through the
+** SQLite code base to cause the statement that provoked the callback
+** to report an error, though the commit will have still occurred. If the
+** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
+** that does not correspond to any valid SQLite error code, the results
+** are undefined.
+**
+** A single database handle may have at most a single write-ahead log callback
+** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
+** previously registered write-ahead log callback. ^The return value is
+** a copy of the third parameter from the previous call, if any, or 0.
+** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
+** overwrite any prior [sqlite3_wal_hook()] settings.
+*/
+SQLITE_API void *sqlite3_wal_hook(
+  sqlite3*,
+  int(*)(void *,sqlite3*,const char*,int),
+  void*
+);
+
+/*
+** CAPI3REF: Configure an auto-checkpoint
+** METHOD: sqlite3
+**
+** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
+** [sqlite3_wal_hook()] that causes any database on [database connection] D
+** to automatically [checkpoint]
+** after committing a transaction if there are N or
+** more frames in the [write-ahead log] file.  ^Passing zero or
+** a negative value as the nFrame parameter disables automatic
+** checkpoints entirely.
+**
+** ^The callback registered by this function replaces any existing callback
+** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
+** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
+** configured by this function.
+**
+** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
+** from SQL.
+**
+** ^Checkpoints initiated by this mechanism are
+** [sqlite3_wal_checkpoint_v2|PASSIVE].
+**
+** ^Every new [database connection] defaults to having the auto-checkpoint
+** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
+** pages.  The use of this interface
+** is only necessary if the default setting is found to be suboptimal
+** for a particular application.
+*/
+SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Checkpoint a database
+** METHOD: sqlite3
+**
+** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
+** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
+**
+** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
+** [write-ahead log] for database X on [database connection] D to be
+** transferred into the database file and for the write-ahead log to
+** be reset.  See the [checkpointing] documentation for addition
+** information.
+**
+** This interface used to be the only way to cause a checkpoint to
+** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
+** interface was added.  This interface is retained for backwards
+** compatibility and as a convenience for applications that need to manually
+** start a callback but which do not need the full power (and corresponding
+** complication) of [sqlite3_wal_checkpoint_v2()].
+*/
+SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Checkpoint a database
+** METHOD: sqlite3
+**
+** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
+** operation on database X of [database connection] D in mode M.  Status
+** information is written back into integers pointed to by L and C.)^
+** ^(The M parameter must be a valid [checkpoint mode]:)^
+**
+** <dl>
+** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
+**   ^Checkpoint as many frames as possible without waiting for any database
+**   readers or writers to finish, then sync the database file if all frames
+**   in the log were checkpointed. ^The [busy-handler callback]
+**   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
+**   ^On the other hand, passive mode might leave the checkpoint unfinished
+**   if there are concurrent readers or writers.
+**
+** <dt>SQLITE_CHECKPOINT_FULL<dd>
+**   ^This mode blocks (it invokes the
+**   [sqlite3_busy_handler|busy-handler callback]) until there is no
+**   database writer and all readers are reading from the most recent database
+**   snapshot. ^It then checkpoints all frames in the log file and syncs the
+**   database file. ^This mode blocks new database writers while it is pending,
+**   but new database readers are allowed to continue unimpeded.
+**
+** <dt>SQLITE_CHECKPOINT_RESTART<dd>
+**   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
+**   that after checkpointing the log file it blocks (calls the
+**   [busy-handler callback])
+**   until all readers are reading from the database file only. ^This ensures
+**   that the next writer will restart the log file from the beginning.
+**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
+**   database writer attempts while it is pending, but does not impede readers.
+**
+** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
+**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
+**   addition that it also truncates the log file to zero bytes just prior
+**   to a successful return.
+** </dl>
+**
+** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
+** the log file or to -1 if the checkpoint could not run because
+** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
+** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
+** log file (including any that were already checkpointed before the function
+** was called) or to -1 if the checkpoint could not run due to an error or
+** because the database is not in WAL mode. ^Note that upon successful
+** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
+** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
+**
+** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
+** any other process is running a checkpoint operation at the same time, the
+** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
+** busy-handler configured, it will not be invoked in this case.
+**
+** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
+** exclusive "writer" lock on the database file. ^If the writer lock cannot be
+** obtained immediately, and a busy-handler is configured, it is invoked and
+** the writer lock retried until either the busy-handler returns 0 or the lock
+** is successfully obtained. ^The busy-handler is also invoked while waiting for
+** database readers as described above. ^If the busy-handler returns 0 before
+** the writer lock is obtained or while waiting for database readers, the
+** checkpoint operation proceeds from that point in the same way as
+** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
+** without blocking any further. ^SQLITE_BUSY is returned in this case.
+**
+** ^If parameter zDb is NULL or points to a zero length string, then the
+** specified operation is attempted on all WAL databases [attached] to
+** [database connection] db.  In this case the
+** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
+** an SQLITE_BUSY error is encountered when processing one or more of the
+** attached WAL databases, the operation is still attempted on any remaining
+** attached databases and SQLITE_BUSY is returned at the end. ^If any other
+** error occurs while processing an attached database, processing is abandoned
+** and the error code is returned to the caller immediately. ^If no error
+** (SQLITE_BUSY or otherwise) is encountered while processing the attached
+** databases, SQLITE_OK is returned.
+**
+** ^If database zDb is the name of an attached database that is not in WAL
+** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
+** zDb is not NULL (or a zero length string) and is not the name of any
+** attached database, SQLITE_ERROR is returned to the caller.
+**
+** ^Unless it returns SQLITE_MISUSE,
+** the sqlite3_wal_checkpoint_v2() interface
+** sets the error information that is queried by
+** [sqlite3_errcode()] and [sqlite3_errmsg()].
+**
+** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
+** from SQL.
+*/
+SQLITE_API int sqlite3_wal_checkpoint_v2(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of attached database (or NULL) */
+  int eMode,                      /* SQLITE_CHECKPOINT_* value */
+  int *pnLog,                     /* OUT: Size of WAL log in frames */
+  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
+);
+
+/*
+** CAPI3REF: Checkpoint Mode Values
+** KEYWORDS: {checkpoint mode}
+**
+** These constants define all valid values for the "checkpoint mode" passed
+** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
+** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
+** meaning of each of these checkpoint modes.
+*/
+#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
+#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
+#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for readers */
+#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
+
+/*
+** CAPI3REF: Virtual Table Interface Configuration
+**
+** This function may be called by either the [xConnect] or [xCreate] method
+** of a [virtual table] implementation to configure
+** various facets of the virtual table interface.
+**
+** If this interface is invoked outside the context of an xConnect or
+** xCreate virtual table method then the behavior is undefined.
+**
+** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
+** [database connection] in which the virtual table is being created and
+** which is passed in as the first argument to the [xConnect] or [xCreate]
+** method that is invoking sqlite3_vtab_config().  The C parameter is one
+** of the [virtual table configuration options].  The presence and meaning
+** of parameters after C depend on which [virtual table configuration option]
+** is used.
+*/
+SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Virtual Table Configuration Options
+** KEYWORDS: {virtual table configuration options}
+** KEYWORDS: {virtual table configuration option}
+**
+** These macros define the various options to the
+** [sqlite3_vtab_config()] interface that [virtual table] implementations
+** can use to customize and optimize their behavior.
+**
+** <dl>
+** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
+** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
+** where X is an integer.  If X is zero, then the [virtual table] whose
+** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
+** support constraints.  In this configuration (which is the default) if
+** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
+** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
+** specified as part of the users SQL statement, regardless of the actual
+** ON CONFLICT mode specified.
+**
+** If X is non-zero, then the virtual table implementation guarantees
+** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
+** any modifications to internal or persistent data structures have been made.
+** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
+** is able to roll back a statement or database transaction, and abandon
+** or continue processing the current SQL statement as appropriate.
+** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
+** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
+** had been ABORT.
+**
+** Virtual table implementations that are required to handle OR REPLACE
+** must do so within the [xUpdate] method. If a call to the
+** [sqlite3_vtab_on_conflict()] function indicates that the current ON
+** CONFLICT policy is REPLACE, the virtual table implementation should
+** silently replace the appropriate rows within the xUpdate callback and
+** return SQLITE_OK. Or, if this is not possible, it may return
+** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
+** constraint handling.
+** </dd>
+**
+** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** prohibits that virtual table from being used from within triggers and
+** views.
+** </dd>
+**
+** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** identify that virtual table as being safe to use from within triggers
+** and views.  Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
+** virtual table can do no serious harm even if it is controlled by a
+** malicious hacker.  Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
+** flag unless absolutely necessary.
+** </dd>
+**
+** [[SQLITE_VTAB_USES_ALL_SCHEMAS]]<dt>SQLITE_VTAB_USES_ALL_SCHEMAS</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_USES_ALL_SCHEMA) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** instruct the query planner to begin at least a read transaction on
+** all schemas ("main", "temp", and any ATTACH-ed databases) whenever the
+** virtual table is used.
+** </dd>
+** </dl>
+*/
+#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
+#define SQLITE_VTAB_INNOCUOUS          2
+#define SQLITE_VTAB_DIRECTONLY         3
+#define SQLITE_VTAB_USES_ALL_SCHEMAS   4
+
+/*
+** CAPI3REF: Determine The Virtual Table Conflict Policy
+**
+** This function may only be called from within a call to the [xUpdate] method
+** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
+** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
+** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
+** of the SQL statement that triggered the call to the [xUpdate] method of the
+** [virtual table].
+*/
+SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
+
+/*
+** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
+**
+** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
+** method of a [virtual table], then it might return true if the
+** column is being fetched as part of an UPDATE operation during which the
+** column value will not change.  The virtual table implementation can use
+** this hint as permission to substitute a return value that is less
+** expensive to compute and that the corresponding
+** [xUpdate] method understands as a "no-change" value.
+**
+** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
+** the column is not changed by the UPDATE statement, then the xColumn
+** method can optionally return without setting a result, without calling
+** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
+** In that case, [sqlite3_value_nochange(X)] will return true for the
+** same column in the [xUpdate] method.
+**
+** The sqlite3_vtab_nochange() routine is an optimization.  Virtual table
+** implementations should continue to give a correct answer even if the
+** sqlite3_vtab_nochange() interface were to always return false.  In the
+** current implementation, the sqlite3_vtab_nochange() interface does always
+** returns false for the enhanced [UPDATE FROM] statement.
+*/
+SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
+
+/*
+** CAPI3REF: Determine The Collation For a Virtual Table Constraint
+** METHOD: sqlite3_index_info
+**
+** This function may only be called from within a call to the [xBestIndex]
+** method of a [virtual table].  This function returns a pointer to a string
+** that is the name of the appropriate collation sequence to use for text
+** comparisons on the constraint identified by its arguments.
+**
+** The first argument must be the pointer to the [sqlite3_index_info] object
+** that is the first parameter to the xBestIndex() method. The second argument
+** must be an index into the aConstraint[] array belonging to the
+** sqlite3_index_info structure passed to xBestIndex.
+**
+** Important:
+** The first parameter must be the same pointer that is passed into the
+** xBestMethod() method.  The first parameter may not be a pointer to a
+** different [sqlite3_index_info] object, even an exact copy.
+**
+** The return value is computed as follows:
+**
+** <ol>
+** <li><p> If the constraint comes from a WHERE clause expression that contains
+**         a [COLLATE operator], then the name of the collation specified by
+**         that COLLATE operator is returned.
+** <li><p> If there is no COLLATE operator, but the column that is the subject
+**         of the constraint specifies an alternative collating sequence via
+**         a [COLLATE clause] on the column definition within the CREATE TABLE
+**         statement that was passed into [sqlite3_declare_vtab()], then the
+**         name of that alternative collating sequence is returned.
+** <li><p> Otherwise, "BINARY" is returned.
+** </ol>
+*/
+SQLITE_API const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
+
+/*
+** CAPI3REF: Determine if a virtual table query is DISTINCT
+** METHOD: sqlite3_index_info
+**
+** This API may only be used from within an [xBestIndex|xBestIndex method]
+** of a [virtual table] implementation. The result of calling this
+** interface from outside of xBestIndex() is undefined and probably harmful.
+**
+** ^The sqlite3_vtab_distinct() interface returns an integer between 0 and
+** 3.  The integer returned by sqlite3_vtab_distinct()
+** gives the virtual table additional information about how the query
+** planner wants the output to be ordered. As long as the virtual table
+** can meet the ordering requirements of the query planner, it may set
+** the "orderByConsumed" flag.
+**
+** <ol><li value="0"><p>
+** ^If the sqlite3_vtab_distinct() interface returns 0, that means
+** that the query planner needs the virtual table to return all rows in the
+** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
+** [sqlite3_index_info] object.  This is the default expectation.  If the
+** virtual table outputs all rows in sorted order, then it is always safe for
+** the xBestIndex method to set the "orderByConsumed" flag, regardless of
+** the return value from sqlite3_vtab_distinct().
+** <li value="1"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
+** that the query planner does not need the rows to be returned in sorted order
+** as long as all rows with the same values in all columns identified by the
+** "aOrderBy" field are adjacent.)^  This mode is used when the query planner
+** is doing a GROUP BY.
+** <li value="2"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
+** that the query planner does not need the rows returned in any particular
+** order, as long as rows with the same values in all columns identified
+** by "aOrderBy" are adjacent.)^  ^(Furthermore, when two or more rows
+** contain the same values for all columns identified by "colUsed", all but
+** one such row may optionally be omitted from the result.)^
+** The virtual table is not required to omit rows that are duplicates
+** over the "colUsed" columns, but if the virtual table can do that without
+** too much extra effort, it could potentially help the query to run faster.
+** This mode is used for a DISTINCT query.
+** <li value="3"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 3, that means the
+** virtual table must return rows in the order defined by "aOrderBy" as
+** if the sqlite3_vtab_distinct() interface had returned 0.  However if
+** two or more rows in the result have the same values for all columns
+** identified by "colUsed", then all but one such row may optionally be
+** omitted.)^  Like when the return value is 2, the virtual table
+** is not required to omit rows that are duplicates over the "colUsed"
+** columns, but if the virtual table can do that without
+** too much extra effort, it could potentially help the query to run faster.
+** This mode is used for queries
+** that have both DISTINCT and ORDER BY clauses.
+** </ol>
+**
+** <p>The following table summarizes the conditions under which the
+** virtual table is allowed to set the "orderByConsumed" flag based on
+** the value returned by sqlite3_vtab_distinct().  This table is a
+** restatement of the previous four paragraphs:
+**
+** <table border=1 cellspacing=0 cellpadding=10 width="90%">
+** <tr>
+** <td valign="top">sqlite3_vtab_distinct() return value
+** <td valign="top">Rows are returned in aOrderBy order
+** <td valign="top">Rows with the same value in all aOrderBy columns are adjacent
+** <td valign="top">Duplicates over all colUsed columns may be omitted
+** <tr><td>0<td>yes<td>yes<td>no
+** <tr><td>1<td>no<td>yes<td>no
+** <tr><td>2<td>no<td>yes<td>yes
+** <tr><td>3<td>yes<td>yes<td>yes
+** </table>
+**
+** ^For the purposes of comparing virtual table output values to see if the
+** values are same value for sorting purposes, two NULL values are considered
+** to be the same.  In other words, the comparison operator is "IS"
+** (or "IS NOT DISTINCT FROM") and not "==".
+**
+** If a virtual table implementation is unable to meet the requirements
+** specified above, then it must not set the "orderByConsumed" flag in the
+** [sqlite3_index_info] object or an incorrect answer may result.
+**
+** ^A virtual table implementation is always free to return rows in any order
+** it wants, as long as the "orderByConsumed" flag is not set.  ^When the
+** the "orderByConsumed" flag is unset, the query planner will add extra
+** [bytecode] to ensure that the final results returned by the SQL query are
+** ordered correctly.  The use of the "orderByConsumed" flag and the
+** sqlite3_vtab_distinct() interface is merely an optimization.  ^Careful
+** use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
+** flag might help queries against a virtual table to run faster.  Being
+** overly aggressive and setting the "orderByConsumed" flag when it is not
+** valid to do so, on the other hand, might cause SQLite to return incorrect
+** results.
+*/
+SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info*);
+
+/*
+** CAPI3REF: Identify and handle IN constraints in xBestIndex
+**
+** This interface may only be used from within an
+** [xBestIndex|xBestIndex() method] of a [virtual table] implementation.
+** The result of invoking this interface from any other context is
+** undefined and probably harmful.
+**
+** ^(A constraint on a virtual table of the form
+** "[IN operator|column IN (...)]" is
+** communicated to the xBestIndex method as a
+** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^  If xBestIndex wants to use
+** this constraint, it must set the corresponding
+** aConstraintUsage[].argvIndex to a positive integer.  ^(Then, under
+** the usual mode of handling IN operators, SQLite generates [bytecode]
+** that invokes the [xFilter|xFilter() method] once for each value
+** on the right-hand side of the IN operator.)^  Thus the virtual table
+** only sees a single value from the right-hand side of the IN operator
+** at a time.
+**
+** In some cases, however, it would be advantageous for the virtual
+** table to see all values on the right-hand of the IN operator all at
+** once.  The sqlite3_vtab_in() interfaces facilitates this in two ways:
+**
+** <ol>
+** <li><p>
+**   ^A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
+**   if and only if the [sqlite3_index_info|P->aConstraint][N] constraint
+**   is an [IN operator] that can be processed all at once.  ^In other words,
+**   sqlite3_vtab_in() with -1 in the third argument is a mechanism
+**   by which the virtual table can ask SQLite if all-at-once processing
+**   of the IN operator is even possible.
+**
+** <li><p>
+**   ^A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
+**   to SQLite that the virtual table does or does not want to process
+**   the IN operator all-at-once, respectively.  ^Thus when the third
+**   parameter (F) is non-negative, this interface is the mechanism by
+**   which the virtual table tells SQLite how it wants to process the
+**   IN operator.
+** </ol>
+**
+** ^The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
+** within the same xBestIndex method call.  ^For any given P,N pair,
+** the return value from sqlite3_vtab_in(P,N,F) will always be the same
+** within the same xBestIndex call.  ^If the interface returns true
+** (non-zero), that means that the constraint is an IN operator
+** that can be processed all-at-once.  ^If the constraint is not an IN
+** operator or cannot be processed all-at-once, then the interface returns
+** false.
+**
+** ^(All-at-once processing of the IN operator is selected if both of the
+** following conditions are met:
+**
+** <ol>
+** <li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
+** integer.  This is how the virtual table tells SQLite that it wants to
+** use the N-th constraint.
+**
+** <li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
+** non-negative had F>=1.
+** </ol>)^
+**
+** ^If either or both of the conditions above are false, then SQLite uses
+** the traditional one-at-a-time processing strategy for the IN constraint.
+** ^If both conditions are true, then the argvIndex-th parameter to the
+** xFilter method will be an [sqlite3_value] that appears to be NULL,
+** but which can be passed to [sqlite3_vtab_in_first()] and
+** [sqlite3_vtab_in_next()] to find all values on the right-hand side
+** of the IN constraint.
+*/
+SQLITE_API int sqlite3_vtab_in(sqlite3_index_info*, int iCons, int bHandle);
+
+/*
+** CAPI3REF: Find all elements on the right-hand side of an IN constraint.
+**
+** These interfaces are only useful from within the
+** [xFilter|xFilter() method] of a [virtual table] implementation.
+** The result of invoking these interfaces from any other context
+** is undefined and probably harmful.
+**
+** The X parameter in a call to sqlite3_vtab_in_first(X,P) or
+** sqlite3_vtab_in_next(X,P) should be one of the parameters to the
+** xFilter method which invokes these routines, and specifically
+** a parameter that was previously selected for all-at-once IN constraint
+** processing use the [sqlite3_vtab_in()] interface in the
+** [xBestIndex|xBestIndex method].  ^(If the X parameter is not
+** an xFilter argument that was selected for all-at-once IN constraint
+** processing, then these routines return [SQLITE_ERROR].)^
+**
+** ^(Use these routines to access all values on the right-hand side
+** of the IN constraint using code like the following:
+**
+** <blockquote><pre>
+**    for(rc=sqlite3_vtab_in_first(pList, &pVal);
+**        rc==SQLITE_OK && pVal;
+**        rc=sqlite3_vtab_in_next(pList, &pVal)
+**    ){
+**      // do something with pVal
+**    }
+**    if( rc!=SQLITE_OK ){
+**      // an error has occurred
+**    }
+** </pre></blockquote>)^
+**
+** ^On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
+** routines return SQLITE_OK and set *P to point to the first or next value
+** on the RHS of the IN constraint.  ^If there are no more values on the
+** right hand side of the IN constraint, then *P is set to NULL and these
+** routines return [SQLITE_DONE].  ^The return value might be
+** some other value, such as SQLITE_NOMEM, in the event of a malfunction.
+**
+** The *ppOut values returned by these routines are only valid until the
+** next call to either of these routines or until the end of the xFilter
+** method from which these routines were called.  If the virtual table
+** implementation needs to retain the *ppOut values for longer, it must make
+** copies.  The *ppOut values are [protected sqlite3_value|protected].
+*/
+SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut);
+SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut);
+
+/*
+** CAPI3REF: Constraint values in xBestIndex()
+** METHOD: sqlite3_index_info
+**
+** This API may only be used from within the [xBestIndex|xBestIndex method]
+** of a [virtual table] implementation. The result of calling this interface
+** from outside of an xBestIndex method are undefined and probably harmful.
+**
+** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
+** the [xBestIndex] method of a [virtual table] implementation, with P being
+** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
+** J being a 0-based index into P->aConstraint[], then this routine
+** attempts to set *V to the value of the right-hand operand of
+** that constraint if the right-hand operand is known.  ^If the
+** right-hand operand is not known, then *V is set to a NULL pointer.
+** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
+** and only if *V is set to a value.  ^The sqlite3_vtab_rhs_value(P,J,V)
+** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
+** constraint is not available.  ^The sqlite3_vtab_rhs_value() interface
+** can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
+** something goes wrong.
+**
+** The sqlite3_vtab_rhs_value() interface is usually only successful if
+** the right-hand operand of a constraint is a literal value in the original
+** SQL statement.  If the right-hand operand is an expression or a reference
+** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
+** will probably return [SQLITE_NOTFOUND].
+**
+** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
+** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand.  For such
+** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
+**
+** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
+** and remains valid for the duration of the xBestIndex method call.
+** ^When xBestIndex returns, the sqlite3_value object returned by
+** sqlite3_vtab_rhs_value() is automatically deallocated.
+**
+** The "_rhs_" in the name of this routine is an abbreviation for
+** "Right-Hand Side".
+*/
+SQLITE_API int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);
+
+/*
+** CAPI3REF: Conflict resolution modes
+** KEYWORDS: {conflict resolution mode}
+**
+** These constants are returned by [sqlite3_vtab_on_conflict()] to
+** inform a [virtual table] implementation what the [ON CONFLICT] mode
+** is for the SQL statement being evaluated.
+**
+** Note that the [SQLITE_IGNORE] constant is also used as a potential
+** return value from the [sqlite3_set_authorizer()] callback and that
+** [SQLITE_ABORT] is also a [result code].
+*/
+#define SQLITE_ROLLBACK 1
+/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
+#define SQLITE_FAIL     3
+/* #define SQLITE_ABORT 4  // Also an error code */
+#define SQLITE_REPLACE  5
+
+/*
+** CAPI3REF: Prepared Statement Scan Status Opcodes
+** KEYWORDS: {scanstatus options}
+**
+** The following constants can be used for the T parameter to the
+** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
+** different metric for sqlite3_stmt_scanstatus() to return.
+**
+** When the value returned to V is a string, space to hold that string is
+** managed by the prepared statement S and will be automatically freed when
+** S is finalized.
+**
+** Not all values are available for all query elements. When a value is
+** not available, the output variable is set to -1 if the value is numeric,
+** or to NULL if it is a string (SQLITE_SCANSTAT_NAME).
+**
+** <dl>
+** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
+** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
+** set to the total number of times that the X-th loop has run.</dd>
+**
+** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
+** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
+** to the total number of rows examined by all iterations of the X-th loop.</dd>
+**
+** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
+** <dd>^The "double" variable pointed to by the V parameter will be set to the
+** query planner's estimate for the average number of rows output from each
+** iteration of the X-th loop.  If the query planner's estimates was accurate,
+** then this value will approximate the quotient NVISIT/NLOOP and the
+** product of this value for all prior loops with the same SELECTID will
+** be the NLOOP value for the current loop.
+**
+** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
+** <dd>^The "const char *" variable pointed to by the V parameter will be set
+** to a zero-terminated UTF-8 string containing the name of the index or table
+** used for the X-th loop.
+**
+** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
+** <dd>^The "const char *" variable pointed to by the V parameter will be set
+** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
+** description for the X-th loop.
+**
+** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECTID</dt>
+** <dd>^The "int" variable pointed to by the V parameter will be set to the
+** id for the X-th query plan element. The id value is unique within the
+** statement. The select-id is the same value as is output in the first
+** column of an [EXPLAIN QUERY PLAN] query.
+**
+** [[SQLITE_SCANSTAT_PARENTID]] <dt>SQLITE_SCANSTAT_PARENTID</dt>
+** <dd>The "int" variable pointed to by the V parameter will be set to the
+** the id of the parent of the current query element, if applicable, or
+** to zero if the query element has no parent. This is the same value as
+** returned in the second column of an [EXPLAIN QUERY PLAN] query.
+**
+** [[SQLITE_SCANSTAT_NCYCLE]] <dt>SQLITE_SCANSTAT_NCYCLE</dt>
+** <dd>The sqlite3_int64 output value is set to the number of cycles,
+** according to the processor time-stamp counter, that elapsed while the
+** query element was being processed. This value is not available for
+** all query elements - if it is unavailable the output variable is
+** set to -1.
+** </dl>
+*/
+#define SQLITE_SCANSTAT_NLOOP    0
+#define SQLITE_SCANSTAT_NVISIT   1
+#define SQLITE_SCANSTAT_EST      2
+#define SQLITE_SCANSTAT_NAME     3
+#define SQLITE_SCANSTAT_EXPLAIN  4
+#define SQLITE_SCANSTAT_SELECTID 5
+#define SQLITE_SCANSTAT_PARENTID 6
+#define SQLITE_SCANSTAT_NCYCLE   7
+
+/*
+** CAPI3REF: Prepared Statement Scan Status
+** METHOD: sqlite3_stmt
+**
+** These interfaces return information about the predicted and measured
+** performance for pStmt.  Advanced applications can use this
+** interface to compare the predicted and the measured performance and
+** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
+**
+** Since this interface is expected to be rarely used, it is only
+** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
+** compile-time option.
+**
+** The "iScanStatusOp" parameter determines which status information to return.
+** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
+** of this interface is undefined. ^The requested measurement is written into
+** a variable pointed to by the "pOut" parameter.
+**
+** The "flags" parameter must be passed a mask of flags. At present only
+** one flag is defined - SQLITE_SCANSTAT_COMPLEX. If SQLITE_SCANSTAT_COMPLEX
+** is specified, then status information is available for all elements
+** of a query plan that are reported by "EXPLAIN QUERY PLAN" output. If
+** SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
+** that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
+** the EXPLAIN QUERY PLAN output) are available. Invoking API
+** sqlite3_stmt_scanstatus() is equivalent to calling
+** sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.
+**
+** Parameter "idx" identifies the specific query element to retrieve statistics
+** for. Query elements are numbered starting from zero. A value of -1 may be
+** to query for statistics regarding the entire query. ^If idx is out of range
+** - less than -1 or greater than or equal to the total number of query
+** elements used to implement the statement - a non-zero value is returned and
+** the variable that pOut points to is unchanged.
+**
+** See also: [sqlite3_stmt_scanstatus_reset()]
+*/
+SQLITE_API int sqlite3_stmt_scanstatus(
+  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
+  int idx,                  /* Index of loop to report on */
+  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
+  void *pOut                /* Result written here */
+);
+SQLITE_API int sqlite3_stmt_scanstatus_v2(
+  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
+  int idx,                  /* Index of loop to report on */
+  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
+  int flags,                /* Mask of flags defined below */
+  void *pOut                /* Result written here */
+);
+
+/*
+** CAPI3REF: Prepared Statement Scan Status
+** KEYWORDS: {scan status flags}
+*/
+#define SQLITE_SCANSTAT_COMPLEX 0x0001
+
+/*
+** CAPI3REF: Zero Scan-Status Counters
+** METHOD: sqlite3_stmt
+**
+** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
+**
+** This API is only available if the library is built with pre-processor
+** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
+*/
+SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Flush caches to disk mid-transaction
+** METHOD: sqlite3
+**
+** ^If a write-transaction is open on [database connection] D when the
+** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
+** pages in the pager-cache that are not currently in use are written out
+** to disk. A dirty page may be in use if a database cursor created by an
+** active SQL statement is reading from it, or if it is page 1 of a database
+** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
+** interface flushes caches for all schemas - "main", "temp", and
+** any [attached] databases.
+**
+** ^If this function needs to obtain extra database locks before dirty pages
+** can be flushed to disk, it does so. ^If those locks cannot be obtained
+** immediately and there is a busy-handler callback configured, it is invoked
+** in the usual manner. ^If the required lock still cannot be obtained, then
+** the database is skipped and an attempt made to flush any dirty pages
+** belonging to the next (if any) database. ^If any databases are skipped
+** because locks cannot be obtained, but no other error occurs, this
+** function returns SQLITE_BUSY.
+**
+** ^If any other error occurs while flushing dirty pages to disk (for
+** example an IO error or out-of-memory condition), then processing is
+** abandoned and an SQLite [error code] is returned to the caller immediately.
+**
+** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
+**
+** ^This function does not set the database handle error code or message
+** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
+*/
+SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
+
+/*
+** CAPI3REF: The pre-update hook.
+** METHOD: sqlite3
+**
+** ^These interfaces are only available if SQLite is compiled using the
+** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
+**
+** ^The [sqlite3_preupdate_hook()] interface registers a callback function
+** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
+** on a database table.
+** ^At most one preupdate hook may be registered at a time on a single
+** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
+** the previous setting.
+** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
+** with a NULL pointer as the second parameter.
+** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
+** the first parameter to callbacks.
+**
+** ^The preupdate hook only fires for changes to real database tables; the
+** preupdate hook is not invoked for changes to [virtual tables] or to
+** system tables like sqlite_sequence or sqlite_stat1.
+**
+** ^The second parameter to the preupdate callback is a pointer to
+** the [database connection] that registered the preupdate hook.
+** ^The third parameter to the preupdate callback is one of the constants
+** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
+** kind of update operation that is about to occur.
+** ^(The fourth parameter to the preupdate callback is the name of the
+** database within the database connection that is being modified.  This
+** will be "main" for the main database or "temp" for TEMP tables or
+** the name given after the AS keyword in the [ATTACH] statement for attached
+** databases.)^
+** ^The fifth parameter to the preupdate callback is the name of the
+** table that is being modified.
+**
+** For an UPDATE or DELETE operation on a [rowid table], the sixth
+** parameter passed to the preupdate callback is the initial [rowid] of the
+** row being modified or deleted. For an INSERT operation on a rowid table,
+** or any operation on a WITHOUT ROWID table, the value of the sixth
+** parameter is undefined. For an INSERT or UPDATE on a rowid table the
+** seventh parameter is the final rowid value of the row being inserted
+** or updated. The value of the seventh parameter passed to the callback
+** function is not defined for operations on WITHOUT ROWID tables, or for
+** DELETE operations on rowid tables.
+**
+** ^The sqlite3_preupdate_hook(D,C,P) function returns the P argument from
+** the previous call on the same [database connection] D, or NULL for
+** the first call on D.
+**
+** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
+** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
+** provide additional information about a preupdate event. These routines
+** may only be called from within a preupdate callback.  Invoking any of
+** these routines from outside of a preupdate callback or with a
+** [database connection] pointer that is different from the one supplied
+** to the preupdate callback results in undefined and probably undesirable
+** behavior.
+**
+** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
+** in the row that is being inserted, updated, or deleted.
+**
+** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
+** a [protected sqlite3_value] that contains the value of the Nth column of
+** the table row before it is updated.  The N parameter must be between 0
+** and one less than the number of columns or the behavior will be
+** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
+** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
+** behavior is undefined.  The [sqlite3_value] that P points to
+** will be destroyed when the preupdate callback returns.
+**
+** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
+** a [protected sqlite3_value] that contains the value of the Nth column of
+** the table row after it is updated.  The N parameter must be between 0
+** and one less than the number of columns or the behavior will be
+** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
+** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
+** behavior is undefined.  The [sqlite3_value] that P points to
+** will be destroyed when the preupdate callback returns.
+**
+** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
+** callback was invoked as a result of a direct insert, update, or delete
+** operation; or 1 for inserts, updates, or deletes invoked by top-level
+** triggers; or 2 for changes resulting from triggers called by top-level
+** triggers; and so forth.
+**
+** When the [sqlite3_blob_write()] API is used to update a blob column,
+** the pre-update hook is invoked with SQLITE_DELETE. This is because the
+** in this case the new values are not available. In this case, when a
+** callback made with op==SQLITE_DELETE is actually a write using the
+** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
+** the index of the column being written. In other cases, where the
+** pre-update hook is being invoked for some other reason, including a
+** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
+**
+** See also:  [sqlite3_update_hook()]
+*/
+#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
+SQLITE_API void *sqlite3_preupdate_hook(
+  sqlite3 *db,
+  void(*xPreUpdate)(
+    void *pCtx,                   /* Copy of third arg to preupdate_hook() */
+    sqlite3 *db,                  /* Database handle */
+    int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
+    char const *zDb,              /* Database name */
+    char const *zName,            /* Table name */
+    sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
+    sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
+  ),
+  void*
+);
+SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
+SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
+SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
+SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
+SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *);
+#endif
+
+/*
+** CAPI3REF: Low-level system error code
+** METHOD: sqlite3
+**
+** ^Attempt to return the underlying operating system error code or error
+** number that caused the most recent I/O error or failure to open a file.
+** The return value is OS-dependent.  For example, on unix systems, after
+** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
+** called to get back the underlying "errno" that caused the problem, such
+** as ENOSPC, EAUTH, EISDIR, and so forth.
+*/
+SQLITE_API int sqlite3_system_errno(sqlite3*);
+
+/*
+** CAPI3REF: Database Snapshot
+** KEYWORDS: {snapshot} {sqlite3_snapshot}
+**
+** An instance of the snapshot object records the state of a [WAL mode]
+** database for some specific point in history.
+**
+** In [WAL mode], multiple [database connections] that are open on the
+** same database file can each be reading a different historical version
+** of the database file.  When a [database connection] begins a read
+** transaction, that connection sees an unchanging copy of the database
+** as it existed for the point in time when the transaction first started.
+** Subsequent changes to the database from other connections are not seen
+** by the reader until a new read transaction is started.
+**
+** The sqlite3_snapshot object records state information about an historical
+** version of the database file so that it is possible to later open a new read
+** transaction that sees that historical version of the database rather than
+** the most recent version.
+*/
+typedef struct sqlite3_snapshot {
+  unsigned char hidden[48];
+} sqlite3_snapshot;
+
+/*
+** CAPI3REF: Record A Database Snapshot
+** CONSTRUCTOR: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
+** new [sqlite3_snapshot] object that records the current state of
+** schema S in database connection D.  ^On success, the
+** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
+** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
+** If there is not already a read-transaction open on schema S when
+** this function is called, one is opened automatically.
+**
+** If a read-transaction is opened by this function, then it is guaranteed
+** that the returned snapshot object may not be invalidated by a database
+** writer or checkpointer until after the read-transaction is closed. This
+** is not guaranteed if a read-transaction is already open when this
+** function is called. In that case, any subsequent write or checkpoint
+** operation on the database may invalidate the returned snapshot handle,
+** even while the read-transaction remains open.
+**
+** The following must be true for this function to succeed. If any of
+** the following statements are false when sqlite3_snapshot_get() is
+** called, SQLITE_ERROR is returned. The final value of *P is undefined
+** in this case.
+**
+** <ul>
+**   <li> The database handle must not be in [autocommit mode].
+**
+**   <li> Schema S of [database connection] D must be a [WAL mode] database.
+**
+**   <li> There must not be a write transaction open on schema S of database
+**        connection D.
+**
+**   <li> One or more transactions must have been written to the current wal
+**        file since it was created on disk (by any connection). This means
+**        that a snapshot cannot be taken on a wal mode database with no wal
+**        file immediately after it is first opened. At least one transaction
+**        must be written to it first.
+** </ul>
+**
+** This function may also return SQLITE_NOMEM.  If it is called with the
+** database handle in autocommit mode but fails for some other reason,
+** whether or not a read transaction is opened on schema S is undefined.
+**
+** The [sqlite3_snapshot] object returned from a successful call to
+** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
+** to avoid a memory leak.
+**
+** The [sqlite3_snapshot_get()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
+  sqlite3 *db,
+  const char *zSchema,
+  sqlite3_snapshot **ppSnapshot
+);
+
+/*
+** CAPI3REF: Start a read transaction on an historical snapshot
+** METHOD: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
+** transaction or upgrades an existing one for schema S of
+** [database connection] D such that the read transaction refers to
+** historical [snapshot] P, rather than the most recent change to the
+** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
+** on success or an appropriate [error code] if it fails.
+**
+** ^In order to succeed, the database connection must not be in
+** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
+** is already a read transaction open on schema S, then the database handle
+** must have no active statements (SELECT statements that have been passed
+** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
+** SQLITE_ERROR is returned if either of these conditions is violated, or
+** if schema S does not exist, or if the snapshot object is invalid.
+**
+** ^A call to sqlite3_snapshot_open() will fail to open if the specified
+** snapshot has been overwritten by a [checkpoint]. In this case
+** SQLITE_ERROR_SNAPSHOT is returned.
+**
+** If there is already a read transaction open when this function is
+** invoked, then the same read transaction remains open (on the same
+** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
+** is returned. If another error code - for example SQLITE_PROTOCOL or an
+** SQLITE_IOERR error code - is returned, then the final state of the
+** read transaction is undefined. If SQLITE_OK is returned, then the
+** read transaction is now open on database snapshot P.
+**
+** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
+** database connection D does not know that the database file for
+** schema S is in [WAL mode].  A database connection might not know
+** that the database file is in [WAL mode] if there has been no prior
+** I/O on that database connection, or if the database entered [WAL mode]
+** after the most recent I/O on the database connection.)^
+** (Hint: Run "[PRAGMA application_id]" against a newly opened
+** database connection in order to make it ready to use snapshots.)
+**
+** The [sqlite3_snapshot_open()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
+  sqlite3 *db,
+  const char *zSchema,
+  sqlite3_snapshot *pSnapshot
+);
+
+/*
+** CAPI3REF: Destroy a snapshot
+** DESTRUCTOR: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
+** The application must eventually free every [sqlite3_snapshot] object
+** using this routine to avoid a memory leak.
+**
+** The [sqlite3_snapshot_free()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
+
+/*
+** CAPI3REF: Compare the ages of two snapshot handles.
+** METHOD: sqlite3_snapshot
+**
+** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
+** of two valid snapshot handles.
+**
+** If the two snapshot handles are not associated with the same database
+** file, the result of the comparison is undefined.
+**
+** Additionally, the result of the comparison is only valid if both of the
+** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
+** last time the wal file was deleted. The wal file is deleted when the
+** database is changed back to rollback mode or when the number of database
+** clients drops to zero. If either snapshot handle was obtained before the
+** wal file was last deleted, the value returned by this function
+** is undefined.
+**
+** Otherwise, this API returns a negative value if P1 refers to an older
+** snapshot than P2, zero if the two handles refer to the same database
+** snapshot, and a positive value if P1 is a newer snapshot than P2.
+**
+** This interface is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SNAPSHOT] option.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
+  sqlite3_snapshot *p1,
+  sqlite3_snapshot *p2
+);
+
+/*
+** CAPI3REF: Recover snapshots from a wal file
+** METHOD: sqlite3_snapshot
+**
+** If a [WAL file] remains on disk after all database connections close
+** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
+** or because the last process to have the database opened exited without
+** calling [sqlite3_close()]) and a new connection is subsequently opened
+** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
+** will only be able to open the last transaction added to the WAL file
+** even though the WAL file contains other valid transactions.
+**
+** This function attempts to scan the WAL file associated with database zDb
+** of database handle db and make all valid snapshots available to
+** sqlite3_snapshot_open(). It is an error if there is already a read
+** transaction open on the database, or if the database is not a WAL mode
+** database.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+**
+** This interface is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SNAPSHOT] option.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Serialize a database
+**
+** The sqlite3_serialize(D,S,P,F) interface returns a pointer to
+** memory that is a serialization of the S database on
+** [database connection] D.  If S is a NULL pointer, the main database is used.
+** If P is not a NULL pointer, then the size of the database in bytes
+** is written into *P.
+**
+** For an ordinary on-disk database file, the serialization is just a
+** copy of the disk file.  For an in-memory database or a "TEMP" database,
+** the serialization is the same sequence of bytes which would be written
+** to disk if that database where backed up to disk.
+**
+** The usual case is that sqlite3_serialize() copies the serialization of
+** the database into memory obtained from [sqlite3_malloc64()] and returns
+** a pointer to that memory.  The caller is responsible for freeing the
+** returned value to avoid a memory leak.  However, if the F argument
+** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
+** are made, and the sqlite3_serialize() function will return a pointer
+** to the contiguous memory representation of the database that SQLite
+** is currently using for that database, or NULL if the no such contiguous
+** memory representation of the database exists.  A contiguous memory
+** representation of the database will usually only exist if there has
+** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
+** values of D and S.
+** The size of the database is written into *P even if the
+** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
+** of the database exists.
+**
+** After the call, if the SQLITE_SERIALIZE_NOCOPY bit had been set,
+** the returned buffer content will remain accessible and unchanged
+** until either the next write operation on the connection or when
+** the connection is closed, and applications must not modify the
+** buffer. If the bit had been clear, the returned buffer will not
+** be accessed by SQLite after the call.
+**
+** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
+** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
+** allocation error occurs.
+**
+** This interface is omitted if SQLite is compiled with the
+** [SQLITE_OMIT_DESERIALIZE] option.
+*/
+SQLITE_API unsigned char *sqlite3_serialize(
+  sqlite3 *db,           /* The database connection */
+  const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
+  sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
+  unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3_serialize
+**
+** Zero or more of the following constants can be OR-ed together for
+** the F argument to [sqlite3_serialize(D,S,P,F)].
+**
+** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
+** a pointer to contiguous in-memory database that it is currently using,
+** without making a copy of the database.  If SQLite is not currently using
+** a contiguous in-memory database, then this option causes
+** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
+** using a contiguous in-memory database if it has been initialized by a
+** prior call to [sqlite3_deserialize()].
+*/
+#define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
+
+/*
+** CAPI3REF: Deserialize a database
+**
+** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
+** [database connection] D to disconnect from database S and then
+** reopen S as an in-memory database based on the serialization contained
+** in P.  The serialized database P is N bytes in size.  M is the size of
+** the buffer P, which might be larger than N.  If M is larger than N, and
+** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
+** permitted to add content to the in-memory database as long as the total
+** size does not exceed M bytes.
+**
+** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
+** invoke sqlite3_free() on the serialization buffer when the database
+** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
+** SQLite will try to increase the buffer size using sqlite3_realloc64()
+** if writes on the database cause it to grow larger than M bytes.
+**
+** Applications must not modify the buffer P or invalidate it before
+** the database connection D is closed.
+**
+** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
+** database is currently in a read transaction or is involved in a backup
+** operation.
+**
+** It is not possible to deserialized into the TEMP database.  If the
+** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
+** function returns SQLITE_ERROR.
+**
+** The deserialized database should not be in [WAL mode].  If the database
+** is in WAL mode, then any attempt to use the database file will result
+** in an [SQLITE_CANTOPEN] error.  The application can set the
+** [file format version numbers] (bytes 18 and 19) of the input database P
+** to 0x01 prior to invoking sqlite3_deserialize(D,S,P,N,M,F) to force the
+** database file into rollback mode and work around this limitation.
+**
+** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
+** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
+** [sqlite3_free()] is invoked on argument P prior to returning.
+**
+** This interface is omitted if SQLite is compiled with the
+** [SQLITE_OMIT_DESERIALIZE] option.
+*/
+SQLITE_API int sqlite3_deserialize(
+  sqlite3 *db,            /* The database connection */
+  const char *zSchema,    /* Which DB to reopen with the deserialization */
+  unsigned char *pData,   /* The serialized database content */
+  sqlite3_int64 szDb,     /* Number bytes in the deserialization */
+  sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
+  unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3_deserialize()
+**
+** The following are allowed values for 6th argument (the F argument) to
+** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
+**
+** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
+** in the P argument is held in memory obtained from [sqlite3_malloc64()]
+** and that SQLite should take ownership of this memory and automatically
+** free it when it has finished using it.  Without this flag, the caller
+** is responsible for freeing any dynamically allocated memory.
+**
+** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
+** grow the size of the database using calls to [sqlite3_realloc64()].  This
+** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
+** Without this flag, the deserialized database cannot increase in size beyond
+** the number of bytes specified by the M parameter.
+**
+** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
+** should be treated as read-only.
+*/
+#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
+#define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
+#define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
+
+/*
+** Undo the hack that converts floating point types to integer for
+** builds on processors without floating point support.
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# undef double
+#endif
+
+#if defined(__wasi__)
+# undef SQLITE_WASI
+# define SQLITE_WASI 1
+# ifndef SQLITE_OMIT_LOAD_EXTENSION
+#  define SQLITE_OMIT_LOAD_EXTENSION
+# endif
+# ifndef SQLITE_THREADSAFE
+#  define SQLITE_THREADSAFE 0
+# endif
+#endif
+
+#ifdef __cplusplus
+}  /* End of the 'extern "C"' block */
+#endif
+/* #endif for SQLITE3_H will be added by mksqlite3.tcl */
+
+/******** Begin file sqlite3rtree.h *********/
+/*
+** 2010 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+
+#ifndef _SQLITE3RTREE_H_
+#define _SQLITE3RTREE_H_
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
+typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
+
+/* The double-precision datatype used by RTree depends on the
+** SQLITE_RTREE_INT_ONLY compile-time option.
+*/
+#ifdef SQLITE_RTREE_INT_ONLY
+  typedef sqlite3_int64 sqlite3_rtree_dbl;
+#else
+  typedef double sqlite3_rtree_dbl;
+#endif
+
+/*
+** Register a geometry callback named zGeom that can be used as part of an
+** R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_geometry_callback(
+  sqlite3 *db,
+  const char *zGeom,
+  int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
+  void *pContext
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the first
+** argument to callbacks registered using rtree_geometry_callback().
+*/
+struct sqlite3_rtree_geometry {
+  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
+  int nParam;                     /* Size of array aParam[] */
+  sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
+  void *pUser;                    /* Callback implementation user data */
+  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
+};
+
+/*
+** Register a 2nd-generation geometry callback named zScore that can be
+** used as part of an R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_query_callback(
+  sqlite3 *db,
+  const char *zQueryFunc,
+  int (*xQueryFunc)(sqlite3_rtree_query_info*),
+  void *pContext,
+  void (*xDestructor)(void*)
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the
+** argument to scored geometry callback registered using
+** sqlite3_rtree_query_callback().
+**
+** Note that the first 5 fields of this structure are identical to
+** sqlite3_rtree_geometry.  This structure is a subclass of
+** sqlite3_rtree_geometry.
+*/
+struct sqlite3_rtree_query_info {
+  void *pContext;                   /* pContext from when function registered */
+  int nParam;                       /* Number of function parameters */
+  sqlite3_rtree_dbl *aParam;        /* value of function parameters */
+  void *pUser;                      /* callback can use this, if desired */
+  void (*xDelUser)(void*);          /* function to free pUser */
+  sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
+  unsigned int *anQueue;            /* Number of pending entries in the queue */
+  int nCoord;                       /* Number of coordinates */
+  int iLevel;                       /* Level of current node or entry */
+  int mxLevel;                      /* The largest iLevel value in the tree */
+  sqlite3_int64 iRowid;             /* Rowid for current entry */
+  sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
+  int eParentWithin;                /* Visibility of parent node */
+  int eWithin;                      /* OUT: Visibility */
+  sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
+  /* The following fields are only available in 3.8.11 and later */
+  sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
+};
+
+/*
+** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
+*/
+#define NOT_WITHIN       0   /* Object completely outside of query region */
+#define PARTLY_WITHIN    1   /* Object partially overlaps query region */
+#define FULLY_WITHIN     2   /* Object fully contained within query region */
+
+
+#ifdef __cplusplus
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif  /* ifndef _SQLITE3RTREE_H_ */
+
+/******** End of sqlite3rtree.h *********/
+/******** Begin file sqlite3session.h *********/
+
+#if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
+#define __SQLITESESSION_H_ 1
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/*
+** CAPI3REF: Session Object Handle
+**
+** An instance of this object is a [session] that can be used to
+** record changes to a database.
+*/
+typedef struct sqlite3_session sqlite3_session;
+
+/*
+** CAPI3REF: Changeset Iterator Handle
+**
+** An instance of this object acts as a cursor for iterating
+** over the elements of a [changeset] or [patchset].
+*/
+typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
+
+/*
+** CAPI3REF: Create A New Session Object
+** CONSTRUCTOR: sqlite3_session
+**
+** Create a new session object attached to database handle db. If successful,
+** a pointer to the new object is written to *ppSession and SQLITE_OK is
+** returned. If an error occurs, *ppSession is set to NULL and an SQLite
+** error code (e.g. SQLITE_NOMEM) is returned.
+**
+** It is possible to create multiple session objects attached to a single
+** database handle.
+**
+** Session objects created using this function should be deleted using the
+** [sqlite3session_delete()] function before the database handle that they
+** are attached to is itself closed. If the database handle is closed before
+** the session object is deleted, then the results of calling any session
+** module function, including [sqlite3session_delete()] on the session object
+** are undefined.
+**
+** Because the session module uses the [sqlite3_preupdate_hook()] API, it
+** is not possible for an application to register a pre-update hook on a
+** database handle that has one or more session objects attached. Nor is
+** it possible to create a session object attached to a database handle for
+** which a pre-update hook is already defined. The results of attempting
+** either of these things are undefined.
+**
+** The session object will be used to create changesets for tables in
+** database zDb, where zDb is either "main", or "temp", or the name of an
+** attached database. It is not an error if database zDb is not attached
+** to the database when the session object is created.
+*/
+SQLITE_API int sqlite3session_create(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of db (e.g. "main") */
+  sqlite3_session **ppSession     /* OUT: New session object */
+);
+
+/*
+** CAPI3REF: Delete A Session Object
+** DESTRUCTOR: sqlite3_session
+**
+** Delete a session object previously allocated using
+** [sqlite3session_create()]. Once a session object has been deleted, the
+** results of attempting to use pSession with any other session module
+** function are undefined.
+**
+** Session objects must be deleted before the database handle to which they
+** are attached is closed. Refer to the documentation for
+** [sqlite3session_create()] for details.
+*/
+SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Configure a Session Object
+** METHOD: sqlite3_session
+**
+** This method is used to configure a session object after it has been
+** created. At present the only valid values for the second parameter are
+** [SQLITE_SESSION_OBJCONFIG_SIZE] and [SQLITE_SESSION_OBJCONFIG_ROWID].
+**
+*/
+SQLITE_API int sqlite3session_object_config(sqlite3_session*, int op, void *pArg);
+
+/*
+** CAPI3REF: Options for sqlite3session_object_config
+**
+** The following values may passed as the the 2nd parameter to
+** sqlite3session_object_config().
+**
+** <dt>SQLITE_SESSION_OBJCONFIG_SIZE <dd>
+**   This option is used to set, clear or query the flag that enables
+**   the [sqlite3session_changeset_size()] API. Because it imposes some
+**   computational overhead, this API is disabled by default. Argument
+**   pArg must point to a value of type (int). If the value is initially
+**   0, then the sqlite3session_changeset_size() API is disabled. If it
+**   is greater than 0, then the same API is enabled. Or, if the initial
+**   value is less than zero, no change is made. In all cases the (int)
+**   variable is set to 1 if the sqlite3session_changeset_size() API is
+**   enabled following the current call, or 0 otherwise.
+**
+**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
+**   the first table has been attached to the session object.
+**
+** <dt>SQLITE_SESSION_OBJCONFIG_ROWID <dd>
+**   This option is used to set, clear or query the flag that enables
+**   collection of data for tables with no explicit PRIMARY KEY.
+**
+**   Normally, tables with no explicit PRIMARY KEY are simply ignored
+**   by the sessions module. However, if this flag is set, it behaves
+**   as if such tables have a column "_rowid_ INTEGER PRIMARY KEY" inserted
+**   as their leftmost columns.
+**
+**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
+**   the first table has been attached to the session object.
+*/
+#define SQLITE_SESSION_OBJCONFIG_SIZE  1
+#define SQLITE_SESSION_OBJCONFIG_ROWID 2
+
+/*
+** CAPI3REF: Enable Or Disable A Session Object
+** METHOD: sqlite3_session
+**
+** Enable or disable the recording of changes by a session object. When
+** enabled, a session object records changes made to the database. When
+** disabled - it does not. A newly created session object is enabled.
+** Refer to the documentation for [sqlite3session_changeset()] for further
+** details regarding how enabling and disabling a session object affects
+** the eventual changesets.
+**
+** Passing zero to this function disables the session. Passing a value
+** greater than zero enables it. Passing a value less than zero is a
+** no-op, and may be used to query the current state of the session.
+**
+** The return value indicates the final state of the session object: 0 if
+** the session is disabled, or 1 if it is enabled.
+*/
+SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
+
+/*
+** CAPI3REF: Set Or Clear the Indirect Change Flag
+** METHOD: sqlite3_session
+**
+** Each change recorded by a session object is marked as either direct or
+** indirect. A change is marked as indirect if either:
+**
+** <ul>
+**   <li> The session object "indirect" flag is set when the change is
+**        made, or
+**   <li> The change is made by an SQL trigger or foreign key action
+**        instead of directly as a result of a users SQL statement.
+** </ul>
+**
+** If a single row is affected by more than one operation within a session,
+** then the change is considered indirect if all operations meet the criteria
+** for an indirect change above, or direct otherwise.
+**
+** This function is used to set, clear or query the session object indirect
+** flag.  If the second argument passed to this function is zero, then the
+** indirect flag is cleared. If it is greater than zero, the indirect flag
+** is set. Passing a value less than zero does not modify the current value
+** of the indirect flag, and may be used to query the current state of the
+** indirect flag for the specified session object.
+**
+** The return value indicates the final state of the indirect flag: 0 if
+** it is clear, or 1 if it is set.
+*/
+SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
+
+/*
+** CAPI3REF: Attach A Table To A Session Object
+** METHOD: sqlite3_session
+**
+** If argument zTab is not NULL, then it is the name of a table to attach
+** to the session object passed as the first argument. All subsequent changes
+** made to the table while the session object is enabled will be recorded. See
+** documentation for [sqlite3session_changeset()] for further details.
+**
+** Or, if argument zTab is NULL, then changes are recorded for all tables
+** in the database. If additional tables are added to the database (by
+** executing "CREATE TABLE" statements) after this call is made, changes for
+** the new tables are also recorded.
+**
+** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
+** defined as part of their CREATE TABLE statement. It does not matter if the
+** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
+** KEY may consist of a single column, or may be a composite key.
+**
+** It is not an error if the named table does not exist in the database. Nor
+** is it an error if the named table does not have a PRIMARY KEY. However,
+** no changes will be recorded in either of these scenarios.
+**
+** Changes are not recorded for individual rows that have NULL values stored
+** in one or more of their PRIMARY KEY columns.
+**
+** SQLITE_OK is returned if the call completes without error. Or, if an error
+** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
+**
+** <h3>Special sqlite_stat1 Handling</h3>
+**
+** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
+** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
+**  <pre>
+**        CREATE TABLE sqlite_stat1(tbl,idx,stat)
+**  </pre>
+**
+** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
+** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
+** are recorded for rows for which (idx IS NULL) is true. However, for such
+** rows a zero-length blob (SQL value X'') is stored in the changeset or
+** patchset instead of a NULL value. This allows such changesets to be
+** manipulated by legacy implementations of sqlite3changeset_invert(),
+** concat() and similar.
+**
+** The sqlite3changeset_apply() function automatically converts the
+** zero-length blob back to a NULL value when updating the sqlite_stat1
+** table. However, if the application calls sqlite3changeset_new(),
+** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
+** iterator directly (including on a changeset iterator passed to a
+** conflict-handler callback) then the X'' value is returned. The application
+** must translate X'' to NULL itself if required.
+**
+** Legacy (older than 3.22.0) versions of the sessions module cannot capture
+** changes made to the sqlite_stat1 table. Legacy versions of the
+** sqlite3changeset_apply() function silently ignore any modifications to the
+** sqlite_stat1 table that are part of a changeset or patchset.
+*/
+SQLITE_API int sqlite3session_attach(
+  sqlite3_session *pSession,      /* Session object */
+  const char *zTab                /* Table name */
+);
+
+/*
+** CAPI3REF: Set a table filter on a Session Object.
+** METHOD: sqlite3_session
+**
+** The second argument (xFilter) is the "filter callback". For changes to rows
+** in tables that are not attached to the Session object, the filter is called
+** to determine whether changes to the table's rows should be tracked or not.
+** If xFilter returns 0, changes are not tracked. Note that once a table is
+** attached, xFilter will not be called again.
+*/
+SQLITE_API void sqlite3session_table_filter(
+  sqlite3_session *pSession,      /* Session object */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of third arg to _filter_table() */
+    const char *zTab              /* Table name */
+  ),
+  void *pCtx                      /* First argument passed to xFilter */
+);
+
+/*
+** CAPI3REF: Generate A Changeset From A Session Object
+** METHOD: sqlite3_session
+**
+** Obtain a changeset containing changes to the tables attached to the
+** session object passed as the first argument. If successful,
+** set *ppChangeset to point to a buffer containing the changeset
+** and *pnChangeset to the size of the changeset in bytes before returning
+** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
+** zero and return an SQLite error code.
+**
+** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
+** each representing a change to a single row of an attached table. An INSERT
+** change contains the values of each field of a new database row. A DELETE
+** contains the original values of each field of a deleted database row. An
+** UPDATE change contains the original values of each field of an updated
+** database row along with the updated values for each updated non-primary-key
+** column. It is not possible for an UPDATE change to represent a change that
+** modifies the values of primary key columns. If such a change is made, it
+** is represented in a changeset as a DELETE followed by an INSERT.
+**
+** Changes are not recorded for rows that have NULL values stored in one or
+** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
+** no corresponding change is present in the changesets returned by this
+** function. If an existing row with one or more NULL values stored in
+** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
+** only an INSERT is appears in the changeset. Similarly, if an existing row
+** with non-NULL PRIMARY KEY values is updated so that one or more of its
+** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
+** DELETE change only.
+**
+** The contents of a changeset may be traversed using an iterator created
+** using the [sqlite3changeset_start()] API. A changeset may be applied to
+** a database with a compatible schema using the [sqlite3changeset_apply()]
+** API.
+**
+** Within a changeset generated by this function, all changes related to a
+** single table are grouped together. In other words, when iterating through
+** a changeset or when applying a changeset to a database, all changes related
+** to a single table are processed before moving on to the next table. Tables
+** are sorted in the same order in which they were attached (or auto-attached)
+** to the sqlite3_session object. The order in which the changes related to
+** a single table are stored is undefined.
+**
+** Following a successful call to this function, it is the responsibility of
+** the caller to eventually free the buffer that *ppChangeset points to using
+** [sqlite3_free()].
+**
+** <h3>Changeset Generation</h3>
+**
+** Once a table has been attached to a session object, the session object
+** records the primary key values of all new rows inserted into the table.
+** It also records the original primary key and other column values of any
+** deleted or updated rows. For each unique primary key value, data is only
+** recorded once - the first time a row with said primary key is inserted,
+** updated or deleted in the lifetime of the session.
+**
+** There is one exception to the previous paragraph: when a row is inserted,
+** updated or deleted, if one or more of its primary key columns contain a
+** NULL value, no record of the change is made.
+**
+** The session object therefore accumulates two types of records - those
+** that consist of primary key values only (created when the user inserts
+** a new record) and those that consist of the primary key values and the
+** original values of other table columns (created when the users deletes
+** or updates a record).
+**
+** When this function is called, the requested changeset is created using
+** both the accumulated records and the current contents of the database
+** file. Specifically:
+**
+** <ul>
+**   <li> For each record generated by an insert, the database is queried
+**        for a row with a matching primary key. If one is found, an INSERT
+**        change is added to the changeset. If no such row is found, no change
+**        is added to the changeset.
+**
+**   <li> For each record generated by an update or delete, the database is
+**        queried for a row with a matching primary key. If such a row is
+**        found and one or more of the non-primary key fields have been
+**        modified from their original values, an UPDATE change is added to
+**        the changeset. Or, if no such row is found in the table, a DELETE
+**        change is added to the changeset. If there is a row with a matching
+**        primary key in the database, but all fields contain their original
+**        values, no change is added to the changeset.
+** </ul>
+**
+** This means, amongst other things, that if a row is inserted and then later
+** deleted while a session object is active, neither the insert nor the delete
+** will be present in the changeset. Or if a row is deleted and then later a
+** row with the same primary key values inserted while a session object is
+** active, the resulting changeset will contain an UPDATE change instead of
+** a DELETE and an INSERT.
+**
+** When a session object is disabled (see the [sqlite3session_enable()] API),
+** it does not accumulate records when rows are inserted, updated or deleted.
+** This may appear to have some counter-intuitive effects if a single row
+** is written to more than once during a session. For example, if a row
+** is inserted while a session object is enabled, then later deleted while
+** the same session object is disabled, no INSERT record will appear in the
+** changeset, even though the delete took place while the session was disabled.
+** Or, if one field of a row is updated while a session is disabled, and
+** another field of the same row is updated while the session is enabled, the
+** resulting changeset will contain an UPDATE change that updates both fields.
+*/
+SQLITE_API int sqlite3session_changeset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
+  void **ppChangeset              /* OUT: Buffer containing changeset */
+);
+
+/*
+** CAPI3REF: Return An Upper-limit For The Size Of The Changeset
+** METHOD: sqlite3_session
+**
+** By default, this function always returns 0. For it to return
+** a useful result, the sqlite3_session object must have been configured
+** to enable this API using sqlite3session_object_config() with the
+** SQLITE_SESSION_OBJCONFIG_SIZE verb.
+**
+** When enabled, this function returns an upper limit, in bytes, for the size
+** of the changeset that might be produced if sqlite3session_changeset() were
+** called. The final changeset size might be equal to or smaller than the
+** size in bytes returned by this function.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Load The Difference Between Tables Into A Session
+** METHOD: sqlite3_session
+**
+** If it is not already attached to the session object passed as the first
+** argument, this function attaches table zTbl in the same manner as the
+** [sqlite3session_attach()] function. If zTbl does not exist, or if it
+** does not have a primary key, this function is a no-op (but does not return
+** an error).
+**
+** Argument zFromDb must be the name of a database ("main", "temp" etc.)
+** attached to the same database handle as the session object that contains
+** a table compatible with the table attached to the session by this function.
+** A table is considered compatible if it:
+**
+** <ul>
+**   <li> Has the same name,
+**   <li> Has the same set of columns declared in the same order, and
+**   <li> Has the same PRIMARY KEY definition.
+** </ul>
+**
+** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
+** are compatible but do not have any PRIMARY KEY columns, it is not an error
+** but no changes are added to the session object. As with other session
+** APIs, tables without PRIMARY KEYs are simply ignored.
+**
+** This function adds a set of changes to the session object that could be
+** used to update the table in database zFrom (call this the "from-table")
+** so that its content is the same as the table attached to the session
+** object (call this the "to-table"). Specifically:
+**
+** <ul>
+**   <li> For each row (primary key) that exists in the to-table but not in
+**     the from-table, an INSERT record is added to the session object.
+**
+**   <li> For each row (primary key) that exists in the to-table but not in
+**     the from-table, a DELETE record is added to the session object.
+**
+**   <li> For each row (primary key) that exists in both tables, but features
+**     different non-PK values in each, an UPDATE record is added to the
+**     session.
+** </ul>
+**
+** To clarify, if this function is called and then a changeset constructed
+** using [sqlite3session_changeset()], then after applying that changeset to
+** database zFrom the contents of the two compatible tables would be
+** identical.
+**
+** It an error if database zFrom does not exist or does not contain the
+** required compatible table.
+**
+** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
+** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
+** may be set to point to a buffer containing an English language error
+** message. It is the responsibility of the caller to free this buffer using
+** sqlite3_free().
+*/
+SQLITE_API int sqlite3session_diff(
+  sqlite3_session *pSession,
+  const char *zFromDb,
+  const char *zTbl,
+  char **pzErrMsg
+);
+
+
+/*
+** CAPI3REF: Generate A Patchset From A Session Object
+** METHOD: sqlite3_session
+**
+** The differences between a patchset and a changeset are that:
+**
+** <ul>
+**   <li> DELETE records consist of the primary key fields only. The
+**        original values of other fields are omitted.
+**   <li> The original values of any modified fields are omitted from
+**        UPDATE records.
+** </ul>
+**
+** A patchset blob may be used with up to date versions of all
+** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
+** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
+** attempting to use a patchset blob with old versions of the
+** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
+**
+** Because the non-primary key "old.*" fields are omitted, no
+** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
+** is passed to the sqlite3changeset_apply() API. Other conflict types work
+** in the same way as for changesets.
+**
+** Changes within a patchset are ordered in the same way as for changesets
+** generated by the sqlite3session_changeset() function (i.e. all changes for
+** a single table are grouped together, tables appear in the order in which
+** they were attached to the session object).
+*/
+SQLITE_API int sqlite3session_patchset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
+  void **ppPatchset               /* OUT: Buffer containing patchset */
+);
+
+/*
+** CAPI3REF: Test if a changeset has recorded any changes.
+**
+** Return non-zero if no changes to attached tables have been recorded by
+** the session object passed as the first argument. Otherwise, if one or
+** more changes have been recorded, return zero.
+**
+** Even if this function returns zero, it is possible that calling
+** [sqlite3session_changeset()] on the session handle may still return a
+** changeset that contains no changes. This can happen when a row in
+** an attached table is modified and then later on the original values
+** are restored. However, if this function returns non-zero, then it is
+** guaranteed that a call to sqlite3session_changeset() will return a
+** changeset containing zero changes.
+*/
+SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Query for the amount of heap memory used by a session object.
+**
+** This API returns the total amount of heap memory in bytes currently
+** used by the session object passed as the only argument.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Create An Iterator To Traverse A Changeset
+** CONSTRUCTOR: sqlite3_changeset_iter
+**
+** Create an iterator used to iterate through the contents of a changeset.
+** If successful, *pp is set to point to the iterator handle and SQLITE_OK
+** is returned. Otherwise, if an error occurs, *pp is set to zero and an
+** SQLite error code is returned.
+**
+** The following functions can be used to advance and query a changeset
+** iterator created by this function:
+**
+** <ul>
+**   <li> [sqlite3changeset_next()]
+**   <li> [sqlite3changeset_op()]
+**   <li> [sqlite3changeset_new()]
+**   <li> [sqlite3changeset_old()]
+** </ul>
+**
+** It is the responsibility of the caller to eventually destroy the iterator
+** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
+** changeset (pChangeset) must remain valid until after the iterator is
+** destroyed.
+**
+** Assuming the changeset blob was created by one of the
+** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
+** [sqlite3changeset_invert()] functions, all changes within the changeset
+** that apply to a single table are grouped together. This means that when
+** an application iterates through a changeset using an iterator created by
+** this function, all changes that relate to a single table are visited
+** consecutively. There is no chance that the iterator will visit a change
+** the applies to table X, then one for table Y, and then later on visit
+** another change for table X.
+**
+** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
+** may be modified by passing a combination of
+** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
+**
+** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
+** and therefore subject to change.
+*/
+SQLITE_API int sqlite3changeset_start(
+  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
+  int nChangeset,                 /* Size of changeset blob in bytes */
+  void *pChangeset                /* Pointer to blob containing changeset */
+);
+SQLITE_API int sqlite3changeset_start_v2(
+  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
+  int nChangeset,                 /* Size of changeset blob in bytes */
+  void *pChangeset,               /* Pointer to blob containing changeset */
+  int flags                       /* SESSION_CHANGESETSTART_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3changeset_start_v2
+**
+** The following flags may passed via the 4th parameter to
+** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
+**
+** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
+**   Invert the changeset while iterating through it. This is equivalent to
+**   inverting a changeset using sqlite3changeset_invert() before applying it.
+**   It is an error to specify this flag with a patchset.
+*/
+#define SQLITE_CHANGESETSTART_INVERT        0x0002
+
+
+/*
+** CAPI3REF: Advance A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function may only be used with iterators created by the function
+** [sqlite3changeset_start()]. If it is called on an iterator passed to
+** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
+** is returned and the call has no effect.
+**
+** Immediately after an iterator is created by sqlite3changeset_start(), it
+** does not point to any change in the changeset. Assuming the changeset
+** is not empty, the first call to this function advances the iterator to
+** point to the first change in the changeset. Each subsequent call advances
+** the iterator to point to the next change in the changeset (if any). If
+** no error occurs and the iterator points to a valid change after a call
+** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
+** Otherwise, if all changes in the changeset have already been visited,
+** SQLITE_DONE is returned.
+**
+** If an error occurs, an SQLite error code is returned. Possible error
+** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
+** SQLITE_NOMEM.
+*/
+SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
+
+/*
+** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
+** is not the case, this function returns [SQLITE_MISUSE].
+**
+** Arguments pOp, pnCol and pzTab may not be NULL. Upon return, three
+** outputs are set through these pointers:
+**
+** *pOp is set to one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
+** depending on the type of change that the iterator currently points to;
+**
+** *pnCol is set to the number of columns in the table affected by the change; and
+**
+** *pzTab is set to point to a nul-terminated utf-8 encoded string containing
+** the name of the table affected by the current change. The buffer remains
+** valid until either sqlite3changeset_next() is called on the iterator
+** or until the conflict-handler function returns.
+**
+** If pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
+** is an indirect change, or false (0) otherwise. See the documentation for
+** [sqlite3session_indirect()] for a description of direct and indirect
+** changes.
+**
+** If no error occurs, SQLITE_OK is returned. If an error does occur, an
+** SQLite error code is returned. The values of the output variables may not
+** be trusted in this case.
+*/
+SQLITE_API int sqlite3changeset_op(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  const char **pzTab,             /* OUT: Pointer to table name */
+  int *pnCol,                     /* OUT: Number of columns in table */
+  int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
+  int *pbIndirect                 /* OUT: True for an 'indirect' change */
+);
+
+/*
+** CAPI3REF: Obtain The Primary Key Definition Of A Table
+** METHOD: sqlite3_changeset_iter
+**
+** For each modified table, a changeset includes the following:
+**
+** <ul>
+**   <li> The number of columns in the table, and
+**   <li> Which of those columns make up the tables PRIMARY KEY.
+** </ul>
+**
+** This function is used to find which columns comprise the PRIMARY KEY of
+** the table modified by the change that iterator pIter currently points to.
+** If successful, *pabPK is set to point to an array of nCol entries, where
+** nCol is the number of columns in the table. Elements of *pabPK are set to
+** 0x01 if the corresponding column is part of the tables primary key, or
+** 0x00 if it is not.
+**
+** If argument pnCol is not NULL, then *pnCol is set to the number of columns
+** in the table.
+**
+** If this function is called when the iterator does not point to a valid
+** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
+** SQLITE_OK is returned and the output variables populated as described
+** above.
+*/
+SQLITE_API int sqlite3changeset_pk(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
+  int *pnCol                      /* OUT: Number of entries in output array */
+);
+
+/*
+** CAPI3REF: Obtain old.* Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
+** Furthermore, it may only be called if the type of change that the iterator
+** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
+** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the vector of
+** original row values stored as part of the UPDATE or DELETE change and
+** returns SQLITE_OK. The name of the function comes from the fact that this
+** is similar to the "old.*" columns available to update or delete triggers.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_old(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
+);
+
+/*
+** CAPI3REF: Obtain new.* Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
+** Furthermore, it may only be called if the type of change that the iterator
+** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
+** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the vector of
+** new row values stored as part of the UPDATE or INSERT change and
+** returns SQLITE_OK. If the change is an UPDATE and does not include
+** a new value for the requested column, *ppValue is set to NULL and
+** SQLITE_OK returned. The name of the function comes from the fact that
+** this is similar to the "new.*" columns available to update or delete
+** triggers.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_new(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
+);
+
+/*
+** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function should only be used with iterator objects passed to a
+** conflict-handler callback by [sqlite3changeset_apply()] with either
+** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
+** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
+** is set to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the
+** "conflicting row" associated with the current conflict-handler callback
+** and returns SQLITE_OK.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_conflict(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: Value from conflicting row */
+);
+
+/*
+** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
+** METHOD: sqlite3_changeset_iter
+**
+** This function may only be called with an iterator passed to an
+** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
+** it sets the output variable to the total number of known foreign key
+** violations in the destination database and returns SQLITE_OK.
+**
+** In all other cases this function returns SQLITE_MISUSE.
+*/
+SQLITE_API int sqlite3changeset_fk_conflicts(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int *pnOut                      /* OUT: Number of FK violations */
+);
+
+
+/*
+** CAPI3REF: Finalize A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function is used to finalize an iterator allocated with
+** [sqlite3changeset_start()].
+**
+** This function should only be called on iterators created using the
+** [sqlite3changeset_start()] function. If an application calls this
+** function with an iterator passed to a conflict-handler by
+** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
+** call has no effect.
+**
+** If an error was encountered within a call to an sqlite3changeset_xxx()
+** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
+** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
+** to that error is returned by this function. Otherwise, SQLITE_OK is
+** returned. This is to allow the following pattern (pseudo-code):
+**
+** <pre>
+**   sqlite3changeset_start();
+**   while( SQLITE_ROW==sqlite3changeset_next() ){
+**     // Do something with change.
+**   }
+**   rc = sqlite3changeset_finalize();
+**   if( rc!=SQLITE_OK ){
+**     // An error has occurred
+**   }
+** </pre>
+*/
+SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
+
+/*
+** CAPI3REF: Invert A Changeset
+**
+** This function is used to "invert" a changeset object. Applying an inverted
+** changeset to a database reverses the effects of applying the uninverted
+** changeset. Specifically:
+**
+** <ul>
+**   <li> Each DELETE change is changed to an INSERT, and
+**   <li> Each INSERT change is changed to a DELETE, and
+**   <li> For each UPDATE change, the old.* and new.* values are exchanged.
+** </ul>
+**
+** This function does not change the order in which changes appear within
+** the changeset. It merely reverses the sense of each individual change.
+**
+** If successful, a pointer to a buffer containing the inverted changeset
+** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
+** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
+** zeroed and an SQLite error code returned.
+**
+** It is the responsibility of the caller to eventually call sqlite3_free()
+** on the *ppOut pointer to free the buffer allocation following a successful
+** call to this function.
+**
+** WARNING/TODO: This function currently assumes that the input is a valid
+** changeset. If it is not, the results are undefined.
+*/
+SQLITE_API int sqlite3changeset_invert(
+  int nIn, const void *pIn,       /* Input changeset */
+  int *pnOut, void **ppOut        /* OUT: Inverse of input */
+);
+
+/*
+** CAPI3REF: Concatenate Two Changeset Objects
+**
+** This function is used to concatenate two changesets, A and B, into a
+** single changeset. The result is a changeset equivalent to applying
+** changeset A followed by changeset B.
+**
+** This function combines the two input changesets using an
+** sqlite3_changegroup object. Calling it produces similar results as the
+** following code fragment:
+**
+** <pre>
+**   sqlite3_changegroup *pGrp;
+**   rc = sqlite3_changegroup_new(&pGrp);
+**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
+**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
+**   if( rc==SQLITE_OK ){
+**     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
+**   }else{
+**     *ppOut = 0;
+**     *pnOut = 0;
+**   }
+** </pre>
+**
+** Refer to the sqlite3_changegroup documentation below for details.
+*/
+SQLITE_API int sqlite3changeset_concat(
+  int nA,                         /* Number of bytes in buffer pA */
+  void *pA,                       /* Pointer to buffer containing changeset A */
+  int nB,                         /* Number of bytes in buffer pB */
+  void *pB,                       /* Pointer to buffer containing changeset B */
+  int *pnOut,                     /* OUT: Number of bytes in output changeset */
+  void **ppOut                    /* OUT: Buffer containing output changeset */
+);
+
+
+/*
+** CAPI3REF: Upgrade the Schema of a Changeset/Patchset
+*/
+SQLITE_API int sqlite3changeset_upgrade(
+  sqlite3 *db,
+  const char *zDb,
+  int nIn, const void *pIn,       /* Input changeset */
+  int *pnOut, void **ppOut        /* OUT: Inverse of input */
+);
+
+
+
+/*
+** CAPI3REF: Changegroup Handle
+**
+** A changegroup is an object used to combine two or more
+** [changesets] or [patchsets]
+*/
+typedef struct sqlite3_changegroup sqlite3_changegroup;
+
+/*
+** CAPI3REF: Create A New Changegroup Object
+** CONSTRUCTOR: sqlite3_changegroup
+**
+** An sqlite3_changegroup object is used to combine two or more changesets
+** (or patchsets) into a single changeset (or patchset). A single changegroup
+** object may combine changesets or patchsets, but not both. The output is
+** always in the same format as the input.
+**
+** If successful, this function returns SQLITE_OK and populates (*pp) with
+** a pointer to a new sqlite3_changegroup object before returning. The caller
+** should eventually free the returned object using a call to
+** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
+** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
+**
+** The usual usage pattern for an sqlite3_changegroup object is as follows:
+**
+** <ul>
+**   <li> It is created using a call to sqlite3changegroup_new().
+**
+**   <li> Zero or more changesets (or patchsets) are added to the object
+**        by calling sqlite3changegroup_add().
+**
+**   <li> The result of combining all input changesets together is obtained
+**        by the application via a call to sqlite3changegroup_output().
+**
+**   <li> The object is deleted using a call to sqlite3changegroup_delete().
+** </ul>
+**
+** Any number of calls to add() and output() may be made between the calls to
+** new() and delete(), and in any order.
+**
+** As well as the regular sqlite3changegroup_add() and
+** sqlite3changegroup_output() functions, also available are the streaming
+** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
+*/
+SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
+
+/*
+** CAPI3REF: Add a Schema to a Changegroup
+** METHOD: sqlite3_changegroup_schema
+**
+** This method may be used to optionally enforce the rule that the changesets
+** added to the changegroup handle must match the schema of database zDb
+** ("main", "temp", or the name of an attached database). If
+** sqlite3changegroup_add() is called to add a changeset that is not compatible
+** with the configured schema, SQLITE_SCHEMA is returned and the changegroup
+** object is left in an undefined state.
+**
+** A changeset schema is considered compatible with the database schema in
+** the same way as for sqlite3changeset_apply(). Specifically, for each
+** table in the changeset, there exists a database table with:
+**
+** <ul>
+**   <li> The name identified by the changeset, and
+**   <li> at least as many columns as recorded in the changeset, and
+**   <li> the primary key columns in the same position as recorded in
+**        the changeset.
+** </ul>
+**
+** The output of the changegroup object always has the same schema as the
+** database nominated using this function. In cases where changesets passed
+** to sqlite3changegroup_add() have fewer columns than the corresponding table
+** in the database schema, these are filled in using the default column
+** values from the database schema. This makes it possible to combined
+** changesets that have different numbers of columns for a single table
+** within a changegroup, provided that they are otherwise compatible.
+*/
+SQLITE_API int sqlite3changegroup_schema(sqlite3_changegroup*, sqlite3*, const char *zDb);
+
+/*
+** CAPI3REF: Add A Changeset To A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** Add all changes within the changeset (or patchset) in buffer pData (size
+** nData bytes) to the changegroup.
+**
+** If the buffer contains a patchset, then all prior calls to this function
+** on the same changegroup object must also have specified patchsets. Or, if
+** the buffer contains a changeset, so must have the earlier calls to this
+** function. Otherwise, SQLITE_ERROR is returned and no changes are added
+** to the changegroup.
+**
+** Rows within the changeset and changegroup are identified by the values in
+** their PRIMARY KEY columns. A change in the changeset is considered to
+** apply to the same row as a change already present in the changegroup if
+** the two rows have the same primary key.
+**
+** Changes to rows that do not already appear in the changegroup are
+** simply copied into it. Or, if both the new changeset and the changegroup
+** contain changes that apply to a single row, the final contents of the
+** changegroup depends on the type of each change, as follows:
+**
+** <table border=1 style="margin-left:8ex;margin-right:8ex">
+**   <tr><th style="white-space:pre">Existing Change  </th>
+**       <th style="white-space:pre">New Change       </th>
+**       <th>Output Change
+**   <tr><td>INSERT <td>INSERT <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>INSERT <td>UPDATE <td>
+**       The INSERT change remains in the changegroup. The values in the
+**       INSERT change are modified as if the row was inserted by the
+**       existing change and then updated according to the new change.
+**   <tr><td>INSERT <td>DELETE <td>
+**       The existing INSERT is removed from the changegroup. The DELETE is
+**       not added.
+**   <tr><td>UPDATE <td>INSERT <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>UPDATE <td>UPDATE <td>
+**       The existing UPDATE remains within the changegroup. It is amended
+**       so that the accompanying values are as if the row was updated once
+**       by the existing change and then again by the new change.
+**   <tr><td>UPDATE <td>DELETE <td>
+**       The existing UPDATE is replaced by the new DELETE within the
+**       changegroup.
+**   <tr><td>DELETE <td>INSERT <td>
+**       If one or more of the column values in the row inserted by the
+**       new change differ from those in the row deleted by the existing
+**       change, the existing DELETE is replaced by an UPDATE within the
+**       changegroup. Otherwise, if the inserted row is exactly the same
+**       as the deleted row, the existing DELETE is simply discarded.
+**   <tr><td>DELETE <td>UPDATE <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>DELETE <td>DELETE <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+** </table>
+**
+** If the new changeset contains changes to a table that is already present
+** in the changegroup, then the number of columns and the position of the
+** primary key columns for the table must be consistent. If this is not the
+** case, this function fails with SQLITE_SCHEMA. Except, if the changegroup
+** object has been configured with a database schema using the
+** sqlite3changegroup_schema() API, then it is possible to combine changesets
+** with different numbers of columns for a single table, provided that
+** they are otherwise compatible.
+**
+** If the input changeset appears to be corrupt and the corruption is
+** detected, SQLITE_CORRUPT is returned. Or, if an out-of-memory condition
+** occurs during processing, this function returns SQLITE_NOMEM.
+**
+** In all cases, if an error occurs the state of the final contents of the
+** changegroup is undefined. If no error occurs, SQLITE_OK is returned.
+*/
+SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
+
+/*
+** CAPI3REF: Add A Single Change To A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** This function adds the single change currently indicated by the iterator
+** passed as the second argument to the changegroup object. The rules for
+** adding the change are just as described for [sqlite3changegroup_add()].
+**
+** If the change is successfully added to the changegroup, SQLITE_OK is
+** returned. Otherwise, an SQLite error code is returned.
+**
+** The iterator must point to a valid entry when this function is called.
+** If it does not, SQLITE_ERROR is returned and no change is added to the
+** changegroup. Additionally, the iterator must not have been opened with
+** the SQLITE_CHANGESETAPPLY_INVERT flag. In this case SQLITE_ERROR is also
+** returned.
+*/
+SQLITE_API int sqlite3changegroup_add_change(
+  sqlite3_changegroup*,
+  sqlite3_changeset_iter*
+);
+
+
+
+/*
+** CAPI3REF: Obtain A Composite Changeset From A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** Obtain a buffer containing a changeset (or patchset) representing the
+** current contents of the changegroup. If the inputs to the changegroup
+** were themselves changesets, the output is a changeset. Or, if the
+** inputs were patchsets, the output is also a patchset.
+**
+** As with the output of the sqlite3session_changeset() and
+** sqlite3session_patchset() functions, all changes related to a single
+** table are grouped together in the output of this function. Tables appear
+** in the same order as for the very first changeset added to the changegroup.
+** If the second or subsequent changesets added to the changegroup contain
+** changes for tables that do not appear in the first changeset, they are
+** appended onto the end of the output changeset, again in the order in
+** which they are first encountered.
+**
+** If an error occurs, an SQLite error code is returned and the output
+** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
+** is returned and the output variables are set to the size of and a
+** pointer to the output buffer, respectively. In this case it is the
+** responsibility of the caller to eventually free the buffer using a
+** call to sqlite3_free().
+*/
+SQLITE_API int sqlite3changegroup_output(
+  sqlite3_changegroup*,
+  int *pnData,                    /* OUT: Size of output buffer in bytes */
+  void **ppData                   /* OUT: Pointer to output buffer */
+);
+
+/*
+** CAPI3REF: Delete A Changegroup Object
+** DESTRUCTOR: sqlite3_changegroup
+*/
+SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
+
+/*
+** CAPI3REF: Apply A Changeset To A Database
+**
+** Apply a changeset or patchset to a database. These functions attempt to
+** update the "main" database attached to handle db with the changes found in
+** the changeset passed via the second and third arguments.
+**
+** The fourth argument (xFilter) passed to these functions is the "filter
+** callback". If it is not NULL, then for each table affected by at least one
+** change in the changeset, the filter callback is invoked with
+** the table name as the second argument, and a copy of the context pointer
+** passed as the sixth argument as the first. If the "filter callback"
+** returns zero, then no attempt is made to apply any changes to the table.
+** Otherwise, if the return value is non-zero or the xFilter argument to
+** is NULL, all changes related to the table are attempted.
+**
+** For each table that is not excluded by the filter callback, this function
+** tests that the target database contains a compatible table. A table is
+** considered compatible if all of the following are true:
+**
+** <ul>
+**   <li> The table has the same name as the name recorded in the
+**        changeset, and
+**   <li> The table has at least as many columns as recorded in the
+**        changeset, and
+**   <li> The table has primary key columns in the same position as
+**        recorded in the changeset.
+** </ul>
+**
+** If there is no compatible table, it is not an error, but none of the
+** changes associated with the table are applied. A warning message is issued
+** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
+** one such warning is issued for each table in the changeset.
+**
+** For each change for which there is a compatible table, an attempt is made
+** to modify the table contents according to the UPDATE, INSERT or DELETE
+** change. If a change cannot be applied cleanly, the conflict handler
+** function passed as the fifth argument to sqlite3changeset_apply() may be
+** invoked. A description of exactly when the conflict handler is invoked for
+** each type of change is below.
+**
+** Unlike the xFilter argument, xConflict may not be passed NULL. The results
+** of passing anything other than a valid function pointer as the xConflict
+** argument are undefined.
+**
+** Each time the conflict handler function is invoked, it must return one
+** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
+** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
+** if the second argument passed to the conflict handler is either
+** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
+** returns an illegal value, any changes already made are rolled back and
+** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
+** actions are taken by sqlite3changeset_apply() depending on the value
+** returned by each invocation of the conflict-handler function. Refer to
+** the documentation for the three
+** [SQLITE_CHANGESET_OMIT|available return values] for details.
+**
+** <dl>
+** <dt>DELETE Changes<dd>
+**   For each DELETE change, the function checks if the target database
+**   contains a row with the same primary key value (or values) as the
+**   original row values stored in the changeset. If it does, and the values
+**   stored in all non-primary key columns also match the values stored in
+**   the changeset the row is deleted from the target database.
+**
+**   If a row with matching primary key values is found, but one or more of
+**   the non-primary key fields contains a value different from the original
+**   row value stored in the changeset, the conflict-handler function is
+**   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
+**   database table has more columns than are recorded in the changeset,
+**   only the values of those non-primary key fields are compared against
+**   the current database contents - any trailing database table columns
+**   are ignored.
+**
+**   If no row with matching primary key values is found in the database,
+**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
+**   passed as the second argument.
+**
+**   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
+**   (which can only happen if a foreign key constraint is violated), the
+**   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
+**   passed as the second argument. This includes the case where the DELETE
+**   operation is attempted because an earlier call to the conflict handler
+**   function returned [SQLITE_CHANGESET_REPLACE].
+**
+** <dt>INSERT Changes<dd>
+**   For each INSERT change, an attempt is made to insert the new row into
+**   the database. If the changeset row contains fewer fields than the
+**   database table, the trailing fields are populated with their default
+**   values.
+**
+**   If the attempt to insert the row fails because the database already
+**   contains a row with the same primary key values, the conflict handler
+**   function is invoked with the second argument set to
+**   [SQLITE_CHANGESET_CONFLICT].
+**
+**   If the attempt to insert the row fails because of some other constraint
+**   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
+**   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
+**   This includes the case where the INSERT operation is re-attempted because
+**   an earlier call to the conflict handler function returned
+**   [SQLITE_CHANGESET_REPLACE].
+**
+** <dt>UPDATE Changes<dd>
+**   For each UPDATE change, the function checks if the target database
+**   contains a row with the same primary key value (or values) as the
+**   original row values stored in the changeset. If it does, and the values
+**   stored in all modified non-primary key columns also match the values
+**   stored in the changeset the row is updated within the target database.
+**
+**   If a row with matching primary key values is found, but one or more of
+**   the modified non-primary key fields contains a value different from an
+**   original row value stored in the changeset, the conflict-handler function
+**   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
+**   UPDATE changes only contain values for non-primary key fields that are
+**   to be modified, only those fields need to match the original values to
+**   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
+**
+**   If no row with matching primary key values is found in the database,
+**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
+**   passed as the second argument.
+**
+**   If the UPDATE operation is attempted, but SQLite returns
+**   SQLITE_CONSTRAINT, the conflict-handler function is invoked with
+**   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
+**   This includes the case where the UPDATE operation is attempted after
+**   an earlier call to the conflict handler function returned
+**   [SQLITE_CHANGESET_REPLACE].
+** </dl>
+**
+** It is safe to execute SQL statements, including those that write to the
+** table that the callback related to, from within the xConflict callback.
+** This can be used to further customize the application's conflict
+** resolution strategy.
+**
+** All changes made by these functions are enclosed in a savepoint transaction.
+** If any other error (aside from a constraint failure when attempting to
+** write to the target database) occurs, then the savepoint transaction is
+** rolled back, restoring the target database to its original state, and an
+** SQLite error code returned.
+**
+** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
+** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
+** may set (*ppRebase) to point to a "rebase" that may be used with the
+** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
+** is set to the size of the buffer in bytes. It is the responsibility of the
+** caller to eventually free any such buffer using sqlite3_free(). The buffer
+** is only allocated and populated if one or more conflicts were encountered
+** while applying the patchset. See comments surrounding the sqlite3_rebaser
+** APIs for further details.
+**
+** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
+** may be modified by passing a combination of
+** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
+**
+** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
+** and therefore subject to change.
+*/
+SQLITE_API int sqlite3changeset_apply(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+);
+SQLITE_API int sqlite3changeset_apply_v2(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase, /* OUT: Rebase data */
+  int flags                       /* SESSION_CHANGESETAPPLY_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3changeset_apply_v2
+**
+** The following flags may passed via the 9th parameter to
+** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
+**
+** <dl>
+** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
+**   Usually, the sessions module encloses all operations performed by
+**   a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
+**   SAVEPOINT is committed if the changeset or patchset is successfully
+**   applied, or rolled back if an error occurs. Specifying this flag
+**   causes the sessions module to omit this savepoint. In this case, if the
+**   caller has an open transaction or savepoint when apply_v2() is called,
+**   it may revert the partially applied changeset by rolling it back.
+**
+** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
+**   Invert the changeset before applying it. This is equivalent to inverting
+**   a changeset using sqlite3changeset_invert() before applying it. It is
+**   an error to specify this flag with a patchset.
+**
+** <dt>SQLITE_CHANGESETAPPLY_IGNORENOOP <dd>
+**   Do not invoke the conflict handler callback for any changes that
+**   would not actually modify the database even if they were applied.
+**   Specifically, this means that the conflict handler is not invoked
+**   for:
+**    <ul>
+**    <li>a delete change if the row being deleted cannot be found,
+**    <li>an update change if the modified fields are already set to
+**        their new values in the conflicting row, or
+**    <li>an insert change if all fields of the conflicting row match
+**        the row being inserted.
+**    </ul>
+**
+** <dt>SQLITE_CHANGESETAPPLY_FKNOACTION <dd>
+**   If this flag it set, then all foreign key constraints in the target
+**   database behave as if they were declared with "ON UPDATE NO ACTION ON
+**   DELETE NO ACTION", even if they are actually CASCADE, RESTRICT, SET NULL
+**   or SET DEFAULT.
+*/
+#define SQLITE_CHANGESETAPPLY_NOSAVEPOINT   0x0001
+#define SQLITE_CHANGESETAPPLY_INVERT        0x0002
+#define SQLITE_CHANGESETAPPLY_IGNORENOOP    0x0004
+#define SQLITE_CHANGESETAPPLY_FKNOACTION    0x0008
+
+/*
+** CAPI3REF: Constants Passed To The Conflict Handler
+**
+** Values that may be passed as the second argument to a conflict-handler.
+**
+** <dl>
+** <dt>SQLITE_CHANGESET_DATA<dd>
+**   The conflict handler is invoked with CHANGESET_DATA as the second argument
+**   when processing a DELETE or UPDATE change if a row with the required
+**   PRIMARY KEY fields is present in the database, but one or more other
+**   (non primary-key) fields modified by the update do not contain the
+**   expected "before" values.
+**
+**   The conflicting row, in this case, is the database row with the matching
+**   primary key.
+**
+** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
+**   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
+**   argument when processing a DELETE or UPDATE change if a row with the
+**   required PRIMARY KEY fields is not present in the database.
+**
+**   There is no conflicting row in this case. The results of invoking the
+**   sqlite3changeset_conflict() API are undefined.
+**
+** <dt>SQLITE_CHANGESET_CONFLICT<dd>
+**   CHANGESET_CONFLICT is passed as the second argument to the conflict
+**   handler while processing an INSERT change if the operation would result
+**   in duplicate primary key values.
+**
+**   The conflicting row in this case is the database row with the matching
+**   primary key.
+**
+** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
+**   If foreign key handling is enabled, and applying a changeset leaves the
+**   database in a state containing foreign key violations, the conflict
+**   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
+**   exactly once before the changeset is committed. If the conflict handler
+**   returns CHANGESET_OMIT, the changes, including those that caused the
+**   foreign key constraint violation, are committed. Or, if it returns
+**   CHANGESET_ABORT, the changeset is rolled back.
+**
+**   No current or conflicting row information is provided. The only function
+**   it is possible to call on the supplied sqlite3_changeset_iter handle
+**   is sqlite3changeset_fk_conflicts().
+**
+** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
+**   If any other constraint violation occurs while applying a change (i.e.
+**   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
+**   invoked with CHANGESET_CONSTRAINT as the second argument.
+**
+**   There is no conflicting row in this case. The results of invoking the
+**   sqlite3changeset_conflict() API are undefined.
+**
+** </dl>
+*/
+#define SQLITE_CHANGESET_DATA        1
+#define SQLITE_CHANGESET_NOTFOUND    2
+#define SQLITE_CHANGESET_CONFLICT    3
+#define SQLITE_CHANGESET_CONSTRAINT  4
+#define SQLITE_CHANGESET_FOREIGN_KEY 5
+
+/*
+** CAPI3REF: Constants Returned By The Conflict Handler
+**
+** A conflict handler callback must return one of the following three values.
+**
+** <dl>
+** <dt>SQLITE_CHANGESET_OMIT<dd>
+**   If a conflict handler returns this value no special action is taken. The
+**   change that caused the conflict is not applied. The session module
+**   continues to the next change in the changeset.
+**
+** <dt>SQLITE_CHANGESET_REPLACE<dd>
+**   This value may only be returned if the second argument to the conflict
+**   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
+**   is not the case, any changes applied so far are rolled back and the
+**   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
+**
+**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
+**   handler, then the conflicting row is either updated or deleted, depending
+**   on the type of change.
+**
+**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
+**   handler, then the conflicting row is removed from the database and a
+**   second attempt to apply the change is made. If this second attempt fails,
+**   the original row is restored to the database before continuing.
+**
+** <dt>SQLITE_CHANGESET_ABORT<dd>
+**   If this value is returned, any changes applied so far are rolled back
+**   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
+** </dl>
+*/
+#define SQLITE_CHANGESET_OMIT       0
+#define SQLITE_CHANGESET_REPLACE    1
+#define SQLITE_CHANGESET_ABORT      2
+
+/*
+** CAPI3REF: Rebasing changesets
+** EXPERIMENTAL
+**
+** Suppose there is a site hosting a database in state S0. And that
+** modifications are made that move that database to state S1 and a
+** changeset recorded (the "local" changeset). Then, a changeset based
+** on S0 is received from another site (the "remote" changeset) and
+** applied to the database. The database is then in state
+** (S1+"remote"), where the exact state depends on any conflict
+** resolution decisions (OMIT or REPLACE) made while applying "remote".
+** Rebasing a changeset is to update it to take those conflict
+** resolution decisions into account, so that the same conflicts
+** do not have to be resolved elsewhere in the network.
+**
+** For example, if both the local and remote changesets contain an
+** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
+**
+**   local:  INSERT INTO t1 VALUES(1, 'v1');
+**   remote: INSERT INTO t1 VALUES(1, 'v2');
+**
+** and the conflict resolution is REPLACE, then the INSERT change is
+** removed from the local changeset (it was overridden). Or, if the
+** conflict resolution was "OMIT", then the local changeset is modified
+** to instead contain:
+**
+**           UPDATE t1 SET b = 'v2' WHERE a=1;
+**
+** Changes within the local changeset are rebased as follows:
+**
+** <dl>
+** <dt>Local INSERT<dd>
+**   This may only conflict with a remote INSERT. If the conflict
+**   resolution was OMIT, then add an UPDATE change to the rebased
+**   changeset. Or, if the conflict resolution was REPLACE, add
+**   nothing to the rebased changeset.
+**
+** <dt>Local DELETE<dd>
+**   This may conflict with a remote UPDATE or DELETE. In both cases the
+**   only possible resolution is OMIT. If the remote operation was a
+**   DELETE, then add no change to the rebased changeset. If the remote
+**   operation was an UPDATE, then the old.* fields of change are updated
+**   to reflect the new.* values in the UPDATE.
+**
+** <dt>Local UPDATE<dd>
+**   This may conflict with a remote UPDATE or DELETE. If it conflicts
+**   with a DELETE, and the conflict resolution was OMIT, then the update
+**   is changed into an INSERT. Any undefined values in the new.* record
+**   from the update change are filled in using the old.* values from
+**   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
+**   the UPDATE change is simply omitted from the rebased changeset.
+**
+**   If conflict is with a remote UPDATE and the resolution is OMIT, then
+**   the old.* values are rebased using the new.* values in the remote
+**   change. Or, if the resolution is REPLACE, then the change is copied
+**   into the rebased changeset with updates to columns also updated by
+**   the conflicting remote UPDATE removed. If this means no columns would
+**   be updated, the change is omitted.
+** </dl>
+**
+** A local change may be rebased against multiple remote changes
+** simultaneously. If a single key is modified by multiple remote
+** changesets, they are combined as follows before the local changeset
+** is rebased:
+**
+** <ul>
+**    <li> If there has been one or more REPLACE resolutions on a
+**         key, it is rebased according to a REPLACE.
+**
+**    <li> If there have been no REPLACE resolutions on a key, then
+**         the local changeset is rebased according to the most recent
+**         of the OMIT resolutions.
+** </ul>
+**
+** Note that conflict resolutions from multiple remote changesets are
+** combined on a per-field basis, not per-row. This means that in the
+** case of multiple remote UPDATE operations, some fields of a single
+** local change may be rebased for REPLACE while others are rebased for
+** OMIT.
+**
+** In order to rebase a local changeset, the remote changeset must first
+** be applied to the local database using sqlite3changeset_apply_v2() and
+** the buffer of rebase information captured. Then:
+**
+** <ol>
+**   <li> An sqlite3_rebaser object is created by calling
+**        sqlite3rebaser_create().
+**   <li> The new object is configured with the rebase buffer obtained from
+**        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
+**        If the local changeset is to be rebased against multiple remote
+**        changesets, then sqlite3rebaser_configure() should be called
+**        multiple times, in the same order that the multiple
+**        sqlite3changeset_apply_v2() calls were made.
+**   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
+**   <li> The sqlite3_rebaser object is deleted by calling
+**        sqlite3rebaser_delete().
+** </ol>
+*/
+typedef struct sqlite3_rebaser sqlite3_rebaser;
+
+/*
+** CAPI3REF: Create a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
+** point to the new object and return SQLITE_OK. Otherwise, if an error
+** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
+** to NULL.
+*/
+SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
+
+/*
+** CAPI3REF: Configure a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Configure the changeset rebaser object to rebase changesets according
+** to the conflict resolutions described by buffer pRebase (size nRebase
+** bytes), which must have been obtained from a previous call to
+** sqlite3changeset_apply_v2().
+*/
+SQLITE_API int sqlite3rebaser_configure(
+  sqlite3_rebaser*,
+  int nRebase, const void *pRebase
+);
+
+/*
+** CAPI3REF: Rebase a changeset
+** EXPERIMENTAL
+**
+** Argument pIn must point to a buffer containing a changeset nIn bytes
+** in size. This function allocates and populates a buffer with a copy
+** of the changeset rebased according to the configuration of the
+** rebaser object passed as the first argument. If successful, (*ppOut)
+** is set to point to the new buffer containing the rebased changeset and
+** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
+** responsibility of the caller to eventually free the new buffer using
+** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
+** are set to zero and an SQLite error code returned.
+*/
+SQLITE_API int sqlite3rebaser_rebase(
+  sqlite3_rebaser*,
+  int nIn, const void *pIn,
+  int *pnOut, void **ppOut
+);
+
+/*
+** CAPI3REF: Delete a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Delete the changeset rebaser object and all associated resources. There
+** should be one call to this function for each successful invocation
+** of sqlite3rebaser_create().
+*/
+SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
+
+/*
+** CAPI3REF: Streaming Versions of API functions.
+**
+** The six streaming API xxx_strm() functions serve similar purposes to the
+** corresponding non-streaming API functions:
+**
+** <table border=1 style="margin-left:8ex;margin-right:8ex">
+**   <tr><th>Streaming function<th>Non-streaming equivalent</th>
+**   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
+**   <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
+**   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
+**   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
+**   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
+**   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
+**   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
+** </table>
+**
+** Non-streaming functions that accept changesets (or patchsets) as input
+** require that the entire changeset be stored in a single buffer in memory.
+** Similarly, those that return a changeset or patchset do so by returning
+** a pointer to a single large buffer allocated using sqlite3_malloc().
+** Normally this is convenient. However, if an application running in a
+** low-memory environment is required to handle very large changesets, the
+** large contiguous memory allocations required can become onerous.
+**
+** In order to avoid this problem, instead of a single large buffer, input
+** is passed to a streaming API functions by way of a callback function that
+** the sessions module invokes to incrementally request input data as it is
+** required. In all cases, a pair of API function parameters such as
+**
+**  <pre>
+**        int nChangeset,
+**        void *pChangeset,
+**  </pre>
+**
+** Is replaced by:
+**
+**  <pre>
+**        int (*xInput)(void *pIn, void *pData, int *pnData),
+**        void *pIn,
+**  </pre>
+**
+** Each time the xInput callback is invoked by the sessions module, the first
+** argument passed is a copy of the supplied pIn context pointer. The second
+** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
+** error occurs the xInput method should copy up to (*pnData) bytes of data
+** into the buffer and set (*pnData) to the actual number of bytes copied
+** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
+** should be set to zero to indicate this. Or, if an error occurs, an SQLite
+** error code should be returned. In all cases, if an xInput callback returns
+** an error, all processing is abandoned and the streaming API function
+** returns a copy of the error code to the caller.
+**
+** In the case of sqlite3changeset_start_strm(), the xInput callback may be
+** invoked by the sessions module at any point during the lifetime of the
+** iterator. If such an xInput callback returns an error, the iterator enters
+** an error state, whereby all subsequent calls to iterator functions
+** immediately fail with the same error code as returned by xInput.
+**
+** Similarly, streaming API functions that return changesets (or patchsets)
+** return them in chunks by way of a callback function instead of via a
+** pointer to a single large buffer. In this case, a pair of parameters such
+** as:
+**
+**  <pre>
+**        int *pnChangeset,
+**        void **ppChangeset,
+**  </pre>
+**
+** Is replaced by:
+**
+**  <pre>
+**        int (*xOutput)(void *pOut, const void *pData, int nData),
+**        void *pOut
+**  </pre>
+**
+** The xOutput callback is invoked zero or more times to return data to
+** the application. The first parameter passed to each call is a copy of the
+** pOut pointer supplied by the application. The second parameter, pData,
+** points to a buffer nData bytes in size containing the chunk of output
+** data being returned. If the xOutput callback successfully processes the
+** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
+** it should return some other SQLite error code. In this case processing
+** is immediately abandoned and the streaming API function returns a copy
+** of the xOutput error code to the application.
+**
+** The sessions module never invokes an xOutput callback with the third
+** parameter set to a value less than or equal to zero. Other than this,
+** no guarantees are made as to the size of the chunks of data returned.
+*/
+SQLITE_API int sqlite3changeset_apply_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+);
+SQLITE_API int sqlite3changeset_apply_v2_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase,
+  int flags
+);
+SQLITE_API int sqlite3changeset_concat_strm(
+  int (*xInputA)(void *pIn, void *pData, int *pnData),
+  void *pInA,
+  int (*xInputB)(void *pIn, void *pData, int *pnData),
+  void *pInB,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changeset_invert_strm(
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changeset_start_strm(
+  sqlite3_changeset_iter **pp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn
+);
+SQLITE_API int sqlite3changeset_start_v2_strm(
+  sqlite3_changeset_iter **pp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int flags
+);
+SQLITE_API int sqlite3session_changeset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3session_patchset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
+    int (*xInput)(void *pIn, void *pData, int *pnData),
+    void *pIn
+);
+SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
+    int (*xOutput)(void *pOut, const void *pData, int nData),
+    void *pOut
+);
+SQLITE_API int sqlite3rebaser_rebase_strm(
+  sqlite3_rebaser *pRebaser,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+
+/*
+** CAPI3REF: Configure global parameters
+**
+** The sqlite3session_config() interface is used to make global configuration
+** changes to the sessions module in order to tune it to the specific needs
+** of the application.
+**
+** The sqlite3session_config() interface is not threadsafe. If it is invoked
+** while any other thread is inside any other sessions method then the
+** results are undefined. Furthermore, if it is invoked after any sessions
+** related objects have been created, the results are also undefined.
+**
+** The first argument to the sqlite3session_config() function must be one
+** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
+** interpretation of the (void*) value passed as the second parameter and
+** the effect of calling this function depends on the value of the first
+** parameter.
+**
+** <dl>
+** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
+**    By default, the sessions module streaming interfaces attempt to input
+**    and output data in approximately 1 KiB chunks. This operand may be used
+**    to set and query the value of this configuration setting. The pointer
+**    passed as the second argument must point to a value of type (int).
+**    If this value is greater than 0, it is used as the new streaming data
+**    chunk size for both input and output. Before returning, the (int) value
+**    pointed to by pArg is set to the final value of the streaming interface
+**    chunk size.
+** </dl>
+**
+** This function returns SQLITE_OK if successful, or an SQLite error code
+** otherwise.
+*/
+SQLITE_API int sqlite3session_config(int op, void *pArg);
+
+/*
+** CAPI3REF: Values for sqlite3session_config().
+*/
+#define SQLITE_SESSION_CONFIG_STRMSIZE 1
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#ifdef __cplusplus
+}
+#endif
+
+#endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
+
+/******** End of sqlite3session.h *********/
+/******** Begin file fts5.h *********/
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Interfaces to extend FTS5. Using the interfaces defined in this file,
+** FTS5 may be extended with:
+**
+**     * custom tokenizers, and
+**     * custom auxiliary functions.
+*/
+
+
+#ifndef _FTS5_H
+#define _FTS5_H
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*************************************************************************
+** CUSTOM AUXILIARY FUNCTIONS
+**
+** Virtual table implementations may overload SQL functions by implementing
+** the sqlite3_module.xFindFunction() method.
+*/
+
+typedef struct Fts5ExtensionApi Fts5ExtensionApi;
+typedef struct Fts5Context Fts5Context;
+typedef struct Fts5PhraseIter Fts5PhraseIter;
+
+typedef void (*fts5_extension_function)(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+);
+
+struct Fts5PhraseIter {
+  const unsigned char *a;
+  const unsigned char *b;
+};
+
+/*
+** EXTENSION API FUNCTIONS
+**
+** xUserData(pFts):
+**   Return a copy of the pUserData pointer passed to the xCreateFunction()
+**   API when the extension function was registered.
+**
+** xColumnTotalSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the FTS5 table. Or, if iCol is
+**   non-negative but less than the number of columns in the table, return
+**   the total number of tokens in column iCol, considering all rows in
+**   the FTS5 table.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+** xColumnCount(pFts):
+**   Return the number of columns in the table.
+**
+** xColumnSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the current row. Or, if iCol is
+**   non-negative but less than the number of columns in the table, set
+**   *pnToken to the number of tokens in column iCol of the current row.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+**   This function may be quite inefficient if used with an FTS5 table
+**   created with the "columnsize=0" option.
+**
+** xColumnText:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the text of column iCol of
+**   the current document. If successful, (*pz) is set to point to a buffer
+**   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
+**   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
+**   if an error occurs, an SQLite error code is returned and the final values
+**   of (*pz) and (*pn) are undefined.
+**
+** xPhraseCount:
+**   Returns the number of phrases in the current query expression.
+**
+** xPhraseSize:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of phrases in the current query, as returned by xPhraseCount,
+**   0 is returned. Otherwise, this function returns the number of tokens in
+**   phrase iPhrase of the query. Phrases are numbered starting from zero.
+**
+** xInstCount:
+**   Set *pnInst to the total number of occurrences of all phrases within
+**   the query within the current row. Return SQLITE_OK if successful, or
+**   an error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always returns 0.
+**
+** xInst:
+**   Query for the details of phrase match iIdx within the current row.
+**   Phrase matches are numbered starting from zero, so the iIdx argument
+**   should be greater than or equal to zero and smaller than the value
+**   output by xInstCount(). If iIdx is less than zero or greater than
+**   or equal to the value returned by xInstCount(), SQLITE_RANGE is returned.
+**
+**   Otherwise, output parameter *piPhrase is set to the phrase number, *piCol
+**   to the column in which it occurs and *piOff the token offset of the
+**   first token of the phrase. SQLITE_OK is returned if successful, or an
+**   error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xRowid:
+**   Returns the rowid of the current row.
+**
+** xTokenize:
+**   Tokenize text using the tokenizer belonging to the FTS5 table.
+**
+** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
+**   This API function is used to query the FTS table for phrase iPhrase
+**   of the current query. Specifically, a query equivalent to:
+**
+**       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
+**
+**   with $p set to a phrase equivalent to the phrase iPhrase of the
+**   current query is executed. Any column filter that applies to
+**   phrase iPhrase of the current query is included in $p. For each
+**   row visited, the callback function passed as the fourth argument
+**   is invoked. The context and API objects passed to the callback
+**   function may be used to access the properties of each matched row.
+**   Invoking Api.xUserData() returns a copy of the pointer passed as
+**   the third argument to pUserData.
+**
+**   If parameter iPhrase is less than zero, or greater than or equal to
+**   the number of phrases in the query, as returned by xPhraseCount(),
+**   this function returns SQLITE_RANGE.
+**
+**   If the callback function returns any value other than SQLITE_OK, the
+**   query is abandoned and the xQueryPhrase function returns immediately.
+**   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
+**   Otherwise, the error code is propagated upwards.
+**
+**   If the query runs to completion without incident, SQLITE_OK is returned.
+**   Or, if some error occurs before the query completes or is aborted by
+**   the callback, an SQLite error code is returned.
+**
+**
+** xSetAuxdata(pFts5, pAux, xDelete)
+**
+**   Save the pointer passed as the second argument as the extension function's
+**   "auxiliary data". The pointer may then be retrieved by the current or any
+**   future invocation of the same fts5 extension function made as part of
+**   the same MATCH query using the xGetAuxdata() API.
+**
+**   Each extension function is allocated a single auxiliary data slot for
+**   each FTS query (MATCH expression). If the extension function is invoked
+**   more than once for a single FTS query, then all invocations share a
+**   single auxiliary data context.
+**
+**   If there is already an auxiliary data pointer when this function is
+**   invoked, then it is replaced by the new pointer. If an xDelete callback
+**   was specified along with the original pointer, it is invoked at this
+**   point.
+**
+**   The xDelete callback, if one is specified, is also invoked on the
+**   auxiliary data pointer after the FTS5 query has finished.
+**
+**   If an error (e.g. an OOM condition) occurs within this function,
+**   the auxiliary data is set to NULL and an error code returned. If the
+**   xDelete parameter was not NULL, it is invoked on the auxiliary data
+**   pointer before returning.
+**
+**
+** xGetAuxdata(pFts5, bClear)
+**
+**   Returns the current auxiliary data pointer for the fts5 extension
+**   function. See the xSetAuxdata() method for details.
+**
+**   If the bClear argument is non-zero, then the auxiliary data is cleared
+**   (set to NULL) before this function returns. In this case the xDelete,
+**   if any, is not invoked.
+**
+**
+** xRowCount(pFts5, pnRow)
+**
+**   This function is used to retrieve the total number of rows in the table.
+**   In other words, the same value that would be returned by:
+**
+**        SELECT count(*) FROM ftstable;
+**
+** xPhraseFirst()
+**   This function is used, along with type Fts5PhraseIter and the xPhraseNext
+**   method, to iterate through all instances of a single query phrase within
+**   the current row. This is the same information as is accessible via the
+**   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
+**   to use, this API may be faster under some circumstances. To iterate
+**   through instances of phrase iPhrase, use the following code:
+**
+**       Fts5PhraseIter iter;
+**       int iCol, iOff;
+**       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
+**           iCol>=0;
+**           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
+**       ){
+**         // An instance of phrase iPhrase at offset iOff of column iCol
+**       }
+**
+**   The Fts5PhraseIter structure is defined above. Applications should not
+**   modify this structure directly - it should only be used as shown above
+**   with the xPhraseFirst() and xPhraseNext() API methods (and by
+**   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always iterates
+**   through an empty set (all calls to xPhraseFirst() set iCol to -1).
+**
+**   In all cases, matches are visited in (column ASC, offset ASC) order.
+**   i.e. all those in column 0, sorted by offset, followed by those in
+**   column 1, etc.
+**
+** xPhraseNext()
+**   See xPhraseFirst above.
+**
+** xPhraseFirstColumn()
+**   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
+**   and xPhraseNext() APIs described above. The difference is that instead
+**   of iterating through all instances of a phrase in the current row, these
+**   APIs are used to iterate through the set of columns in the current row
+**   that contain one or more instances of a specified phrase. For example:
+**
+**       Fts5PhraseIter iter;
+**       int iCol;
+**       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
+**           iCol>=0;
+**           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
+**       ){
+**         // Column iCol contains at least one instance of phrase iPhrase
+**       }
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" option. If the FTS5 table is created with either
+**   "detail=none" "content=" option (i.e. if it is a contentless table),
+**   then this API always iterates through an empty set (all calls to
+**   xPhraseFirstColumn() set iCol to -1).
+**
+**   The information accessed using this API and its companion
+**   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
+**   (or xInst/xInstCount). The chief advantage of this API is that it is
+**   significantly more efficient than those alternatives when used with
+**   "detail=column" tables.
+**
+** xPhraseNextColumn()
+**   See xPhraseFirstColumn above.
+**
+** xQueryToken(pFts5, iPhrase, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase iPhrase of the current
+**   query. Before returning, output parameter *ppToken is set to point
+**   to a buffer containing the requested token, and *pnToken to the
+**   size of this buffer in bytes.
+**
+**   If iPhrase or iToken are less than zero, or if iPhrase is greater than
+**   or equal to the number of phrases in the query as reported by
+**   xPhraseCount(), or if iToken is equal to or greater than the number of
+**   tokens in the phrase, SQLITE_RANGE is returned and *ppToken and *pnToken
+     are both zeroed.
+**
+**   The output text is not a copy of the query text that specified the
+**   token. It is the output of the tokenizer module. For tokendata=1
+**   tables, this includes any embedded 0x00 and trailing data.
+**
+** xInstToken(pFts5, iIdx, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase hit iIdx within the
+**   current row. If iIdx is less than zero or greater than or equal to the
+**   value returned by xInstCount(), SQLITE_RANGE is returned.  Otherwise,
+**   output variable (*ppToken) is set to point to a buffer containing the
+**   matching document token, and (*pnToken) to the size of that buffer in
+**   bytes.
+**
+**   The output text is not a copy of the document text that was tokenized.
+**   It is the output of the tokenizer module. For tokendata=1 tables, this
+**   includes any embedded 0x00 and trailing data.
+**
+**   This API may be slow in some cases if the token identified by parameters
+**   iIdx and iToken matched a prefix token in the query. In most cases, the
+**   first call to this API for each prefix token in the query is forced
+**   to scan the portion of the full-text index that matches the prefix
+**   token to collect the extra data required by this API. If the prefix
+**   token matches a large number of token instances in the document set,
+**   this may be a performance problem.
+**
+**   If the user knows in advance that a query may use this API for a
+**   prefix token, FTS5 may be configured to collect all required data as part
+**   of the initial querying of the full-text index, avoiding the second scan
+**   entirely. This also causes prefix queries that do not use this API to
+**   run more slowly and use more memory. FTS5 may be configured in this way
+**   either on a per-table basis using the [FTS5 insttoken | 'insttoken']
+**   option, or on a per-query basis using the
+**   [fts5_insttoken | fts5_insttoken()] user function.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xColumnLocale(pFts5, iIdx, pzLocale, pnLocale)
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the locale associated
+**   with column iCol of the current row. Usually, there is no associated
+**   locale, and output parameters (*pzLocale) and (*pnLocale) are set
+**   to NULL and 0, respectively. However, if the fts5_locale() function
+**   was used to associate a locale with the value when it was inserted
+**   into the fts5 table, then (*pzLocale) is set to point to a nul-terminated
+**   buffer containing the name of the locale in utf-8 encoding. (*pnLocale)
+**   is set to the size in bytes of the buffer, not including the
+**   nul-terminator.
+**
+**   If successful, SQLITE_OK is returned. Or, if an error occurs, an
+**   SQLite error code is returned. The final value of the output parameters
+**   is undefined in this case.
+**
+** xTokenize_v2:
+**   Tokenize text using the tokenizer belonging to the FTS5 table. This
+**   API is the same as the xTokenize() API, except that it allows a tokenizer
+**   locale to be specified.
+*/
+struct Fts5ExtensionApi {
+  int iVersion;                   /* Currently always set to 4 */
+
+  void *(*xUserData)(Fts5Context*);
+
+  int (*xColumnCount)(Fts5Context*);
+  int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
+  int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
+
+  int (*xTokenize)(Fts5Context*,
+    const char *pText, int nText, /* Text to tokenize */
+    void *pCtx,                   /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+
+  int (*xPhraseCount)(Fts5Context*);
+  int (*xPhraseSize)(Fts5Context*, int iPhrase);
+
+  int (*xInstCount)(Fts5Context*, int *pnInst);
+  int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
+
+  sqlite3_int64 (*xRowid)(Fts5Context*);
+  int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
+
+  int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
+    int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
+  );
+  int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
+  void *(*xGetAuxdata)(Fts5Context*, int bClear);
+
+  int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
+  void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
+
+  int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
+  void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
+
+  /* Below this point are iVersion>=3 only */
+  int (*xQueryToken)(Fts5Context*,
+      int iPhrase, int iToken,
+      const char **ppToken, int *pnToken
+  );
+  int (*xInstToken)(Fts5Context*, int iIdx, int iToken, const char**, int*);
+
+  /* Below this point are iVersion>=4 only */
+  int (*xColumnLocale)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xTokenize_v2)(Fts5Context*,
+    const char *pText, int nText,      /* Text to tokenize */
+    const char *pLocale, int nLocale,  /* Locale to pass to tokenizer */
+    void *pCtx,                        /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+};
+
+/*
+** CUSTOM AUXILIARY FUNCTIONS
+*************************************************************************/
+
+/*************************************************************************
+** CUSTOM TOKENIZERS
+**
+** Applications may also register custom tokenizer types. A tokenizer
+** is registered by providing fts5 with a populated instance of the
+** following structure. All structure methods must be defined, setting
+** any member of the fts5_tokenizer struct to NULL leads to undefined
+** behaviour. The structure methods are expected to function as follows:
+**
+** xCreate:
+**   This function is used to allocate and initialize a tokenizer instance.
+**   A tokenizer instance is required to actually tokenize text.
+**
+**   The first argument passed to this function is a copy of the (void*)
+**   pointer provided by the application when the fts5_tokenizer_v2 object
+**   was registered with FTS5 (the third argument to xCreateTokenizer()).
+**   The second and third arguments are an array of nul-terminated strings
+**   containing the tokenizer arguments, if any, specified following the
+**   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
+**   to create the FTS5 table.
+**
+**   The final argument is an output variable. If successful, (*ppOut)
+**   should be set to point to the new tokenizer handle and SQLITE_OK
+**   returned. If an error occurs, some value other than SQLITE_OK should
+**   be returned. In this case, fts5 assumes that the final value of *ppOut
+**   is undefined.
+**
+** xDelete:
+**   This function is invoked to delete a tokenizer handle previously
+**   allocated using xCreate(). Fts5 guarantees that this function will
+**   be invoked exactly once for each successful call to xCreate().
+**
+** xTokenize:
+**   This function is expected to tokenize the nText byte string indicated
+**   by argument pText. pText may or may not be nul-terminated. The first
+**   argument passed to this function is a pointer to an Fts5Tokenizer object
+**   returned by an earlier call to xCreate().
+**
+**   The third argument indicates the reason that FTS5 is requesting
+**   tokenization of the supplied text. This is always one of the following
+**   four values:
+**
+**   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
+**            or removed from the FTS table. The tokenizer is being invoked to
+**            determine the set of tokens to add to (or delete from) the
+**            FTS index.
+**
+**       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
+**            against the FTS index. The tokenizer is being called to tokenize
+**            a bareword or quoted string specified as part of the query.
+**
+**       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
+**            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
+**            followed by a "*" character, indicating that the last token
+**            returned by the tokenizer will be treated as a token prefix.
+**
+**       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
+**            satisfy an fts5_api.xTokenize() request made by an auxiliary
+**            function. Or an fts5_api.xColumnSize() request made by the same
+**            on a columnsize=0 database.
+**   </ul>
+**
+**   The sixth and seventh arguments passed to xTokenize() - pLocale and
+**   nLocale - are a pointer to a buffer containing the locale to use for
+**   tokenization (e.g. "en_US") and its size in bytes, respectively. The
+**   pLocale buffer is not nul-terminated. pLocale may be passed NULL (in
+**   which case nLocale is always 0) to indicate that the tokenizer should
+**   use its default locale.
+**
+**   For each token in the input string, the supplied callback xToken() must
+**   be invoked. The first argument to it should be a copy of the pointer
+**   passed as the second argument to xTokenize(). The third and fourth
+**   arguments are a pointer to a buffer containing the token text, and the
+**   size of the token in bytes. The 4th and 5th arguments are the byte offsets
+**   of the first byte of and first byte immediately following the text from
+**   which the token is derived within the input.
+**
+**   The second argument passed to the xToken() callback ("tflags") should
+**   normally be set to 0. The exception is if the tokenizer supports
+**   synonyms. In this case see the discussion below for details.
+**
+**   FTS5 assumes the xToken() callback is invoked for each token in the
+**   order that they occur within the input text.
+**
+**   If an xToken() callback returns any value other than SQLITE_OK, then
+**   the tokenization should be abandoned and the xTokenize() method should
+**   immediately return a copy of the xToken() return value. Or, if the
+**   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
+**   if an error occurs with the xTokenize() implementation itself, it
+**   may abandon the tokenization and return any error code other than
+**   SQLITE_OK or SQLITE_DONE.
+**
+**   If the tokenizer is registered using an fts5_tokenizer_v2 object,
+**   then the xTokenize() method has two additional arguments - pLocale
+**   and nLocale. These specify the locale that the tokenizer should use
+**   for the current request. If pLocale and nLocale are both 0, then the
+**   tokenizer should use its default locale. Otherwise, pLocale points to
+**   an nLocale byte buffer containing the name of the locale to use as utf-8
+**   text. pLocale is not nul-terminated.
+**
+** FTS5_TOKENIZER
+**
+** There is also an fts5_tokenizer object. This is an older, deprecated,
+** version of fts5_tokenizer_v2. It is similar except that:
+**
+**  <ul>
+**    <li> There is no "iVersion" field, and
+**    <li> The xTokenize() method does not take a locale argument.
+**  </ul>
+**
+** Legacy fts5_tokenizer tokenizers must be registered using the
+** legacy xCreateTokenizer() function, instead of xCreateTokenizer_v2().
+**
+** Tokenizer implementations registered using either API may be retrieved
+** using both xFindTokenizer() and xFindTokenizer_v2().
+**
+** SYNONYM SUPPORT
+**
+**   Custom tokenizers may also support synonyms. Consider a case in which a
+**   user wishes to query for a phrase such as "first place". Using the
+**   built-in tokenizers, the FTS5 query 'first + place' will match instances
+**   of "first place" within the document set, but not alternative forms
+**   such as "1st place". In some applications, it would be better to match
+**   all instances of "first place" or "1st place" regardless of which form
+**   the user specified in the MATCH query text.
+**
+**   There are several ways to approach this in FTS5:
+**
+**   <ol><li> By mapping all synonyms to a single token. In this case, using
+**            the above example, this means that the tokenizer returns the
+**            same token for inputs "first" and "1st". Say that token is in
+**            fact "first", so that when the user inserts the document "I won
+**            1st place" entries are added to the index for tokens "i", "won",
+**            "first" and "place". If the user then queries for '1st + place',
+**            the tokenizer substitutes "first" for "1st" and the query works
+**            as expected.
+**
+**       <li> By querying the index for all synonyms of each query term
+**            separately. In this case, when tokenizing query text, the
+**            tokenizer may provide multiple synonyms for a single term
+**            within the document. FTS5 then queries the index for each
+**            synonym individually. For example, faced with the query:
+**
+**   <codeblock>
+**     ... MATCH 'first place'</codeblock>
+**
+**            the tokenizer offers both "1st" and "first" as synonyms for the
+**            first token in the MATCH query and FTS5 effectively runs a query
+**            similar to:
+**
+**   <codeblock>
+**     ... MATCH '(first OR 1st) place'</codeblock>
+**
+**            except that, for the purposes of auxiliary functions, the query
+**            still appears to contain just two phrases - "(first OR 1st)"
+**            being treated as a single phrase.
+**
+**       <li> By adding multiple synonyms for a single term to the FTS index.
+**            Using this method, when tokenizing document text, the tokenizer
+**            provides multiple synonyms for each token. So that when a
+**            document such as "I won first place" is tokenized, entries are
+**            added to the FTS index for "i", "won", "first", "1st" and
+**            "place".
+**
+**            This way, even if the tokenizer does not provide synonyms
+**            when tokenizing query text (it should not - to do so would be
+**            inefficient), it doesn't matter if the user queries for
+**            'first + place' or '1st + place', as there are entries in the
+**            FTS index corresponding to both forms of the first token.
+**   </ol>
+**
+**   Whether it is parsing document or query text, any call to xToken that
+**   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
+**   is considered to supply a synonym for the previous token. For example,
+**   when parsing the document "I won first place", a tokenizer that supports
+**   synonyms would call xToken() 5 times, as follows:
+**
+**   <codeblock>
+**       xToken(pCtx, 0, "i",                      1,  0,  1);
+**       xToken(pCtx, 0, "won",                    3,  2,  5);
+**       xToken(pCtx, 0, "first",                  5,  6, 11);
+**       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
+**       xToken(pCtx, 0, "place",                  5, 12, 17);
+**</codeblock>
+**
+**   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
+**   xToken() is called. Multiple synonyms may be specified for a single token
+**   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
+**   There is no limit to the number of synonyms that may be provided for a
+**   single token.
+**
+**   In many cases, method (1) above is the best approach. It does not add
+**   extra data to the FTS index or require FTS5 to query for multiple terms,
+**   so it is efficient in terms of disk space and query speed. However, it
+**   does not support prefix queries very well. If, as suggested above, the
+**   token "first" is substituted for "1st" by the tokenizer, then the query:
+**
+**   <codeblock>
+**     ... MATCH '1s*'</codeblock>
+**
+**   will not match documents that contain the token "1st" (as the tokenizer
+**   will probably not map "1s" to any prefix of "first").
+**
+**   For full prefix support, method (3) may be preferred. In this case,
+**   because the index contains entries for both "first" and "1st", prefix
+**   queries such as 'fi*' or '1s*' will match correctly. However, because
+**   extra entries are added to the FTS index, this method uses more space
+**   within the database.
+**
+**   Method (2) offers a midpoint between (1) and (3). Using this method,
+**   a query such as '1s*' will match documents that contain the literal
+**   token "1st", but not "first" (assuming the tokenizer is not able to
+**   provide synonyms for prefixes). However, a non-prefix query like '1st'
+**   will match against "1st" and "first". This method does not require
+**   extra disk space, as no extra entries are added to the FTS index.
+**   On the other hand, it may require more CPU cycles to run MATCH queries,
+**   as separate queries of the FTS index are required for each synonym.
+**
+**   When using methods (2) or (3), it is important that the tokenizer only
+**   provide synonyms when tokenizing document text (method (3)) or query
+**   text (method (2)), not both. Doing so will not cause any errors, but is
+**   inefficient.
+*/
+typedef struct Fts5Tokenizer Fts5Tokenizer;
+typedef struct fts5_tokenizer_v2 fts5_tokenizer_v2;
+struct fts5_tokenizer_v2 {
+  int iVersion;             /* Currently always 2 */
+
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      const char *pLocale, int nLocale,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+/*
+** New code should use the fts5_tokenizer_v2 type to define tokenizer
+** implementations. The following type is included for legacy applications
+** that still use it.
+*/
+typedef struct fts5_tokenizer fts5_tokenizer;
+struct fts5_tokenizer {
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+
+/* Flags that may be passed as the third argument to xTokenize() */
+#define FTS5_TOKENIZE_QUERY     0x0001
+#define FTS5_TOKENIZE_PREFIX    0x0002
+#define FTS5_TOKENIZE_DOCUMENT  0x0004
+#define FTS5_TOKENIZE_AUX       0x0008
+
+/* Flags that may be passed by the tokenizer implementation back to FTS5
+** as the third argument to the supplied xToken callback. */
+#define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
+
+/*
+** END OF CUSTOM TOKENIZERS
+*************************************************************************/
+
+/*************************************************************************
+** FTS5 EXTENSION REGISTRATION API
+*/
+typedef struct fts5_api fts5_api;
+struct fts5_api {
+  int iVersion;                   /* Currently always set to 3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer *pTokenizer
+  );
+
+  /* Create a new auxiliary function */
+  int (*xCreateFunction)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_extension_function xFunction,
+    void (*xDestroy)(void*)
+  );
+
+  /* APIs below this point are only available if iVersion>=3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer_v2 *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer_v2 **ppTokenizer
+  );
+};
+
+/*
+** END OF REGISTRATION API
+*************************************************************************/
+
+#ifdef __cplusplus
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* _FTS5_H */
+
+/******** End of fts5.h *********/
+#endif /* SQLITE3_H */
diff --git a/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3/sqlite3ext.h b/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3/sqlite3ext.h
new file mode 100644
index 0000000..ae0949b
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/Release/obj/gen/sqlite3/sqlite3ext.h
@@ -0,0 +1,719 @@
+/*
+** 2006 June 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the SQLite interface for use by
+** shared libraries that want to be imported as extensions into
+** an SQLite instance.  Shared libraries that intend to be loaded
+** as extensions by SQLite should #include this file instead of 
+** sqlite3.h.
+*/
+#ifndef SQLITE3EXT_H
+#define SQLITE3EXT_H
+#include "sqlite3.h"
+
+/*
+** The following structure holds pointers to all of the SQLite API
+** routines.
+**
+** WARNING:  In order to maintain backwards compatibility, add new
+** interfaces to the end of this structure only.  If you insert new
+** interfaces in the middle of this structure, then older different
+** versions of SQLite will not be able to load each other's shared
+** libraries!
+*/
+struct sqlite3_api_routines {
+  void * (*aggregate_context)(sqlite3_context*,int nBytes);
+  int  (*aggregate_count)(sqlite3_context*);
+  int  (*bind_blob)(sqlite3_stmt*,int,const void*,int n,void(*)(void*));
+  int  (*bind_double)(sqlite3_stmt*,int,double);
+  int  (*bind_int)(sqlite3_stmt*,int,int);
+  int  (*bind_int64)(sqlite3_stmt*,int,sqlite_int64);
+  int  (*bind_null)(sqlite3_stmt*,int);
+  int  (*bind_parameter_count)(sqlite3_stmt*);
+  int  (*bind_parameter_index)(sqlite3_stmt*,const char*zName);
+  const char * (*bind_parameter_name)(sqlite3_stmt*,int);
+  int  (*bind_text)(sqlite3_stmt*,int,const char*,int n,void(*)(void*));
+  int  (*bind_text16)(sqlite3_stmt*,int,const void*,int,void(*)(void*));
+  int  (*bind_value)(sqlite3_stmt*,int,const sqlite3_value*);
+  int  (*busy_handler)(sqlite3*,int(*)(void*,int),void*);
+  int  (*busy_timeout)(sqlite3*,int ms);
+  int  (*changes)(sqlite3*);
+  int  (*close)(sqlite3*);
+  int  (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                           int eTextRep,const char*));
+  int  (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                             int eTextRep,const void*));
+  const void * (*column_blob)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes16)(sqlite3_stmt*,int iCol);
+  int  (*column_count)(sqlite3_stmt*pStmt);
+  const char * (*column_database_name)(sqlite3_stmt*,int);
+  const void * (*column_database_name16)(sqlite3_stmt*,int);
+  const char * (*column_decltype)(sqlite3_stmt*,int i);
+  const void * (*column_decltype16)(sqlite3_stmt*,int);
+  double  (*column_double)(sqlite3_stmt*,int iCol);
+  int  (*column_int)(sqlite3_stmt*,int iCol);
+  sqlite_int64  (*column_int64)(sqlite3_stmt*,int iCol);
+  const char * (*column_name)(sqlite3_stmt*,int);
+  const void * (*column_name16)(sqlite3_stmt*,int);
+  const char * (*column_origin_name)(sqlite3_stmt*,int);
+  const void * (*column_origin_name16)(sqlite3_stmt*,int);
+  const char * (*column_table_name)(sqlite3_stmt*,int);
+  const void * (*column_table_name16)(sqlite3_stmt*,int);
+  const unsigned char * (*column_text)(sqlite3_stmt*,int iCol);
+  const void * (*column_text16)(sqlite3_stmt*,int iCol);
+  int  (*column_type)(sqlite3_stmt*,int iCol);
+  sqlite3_value* (*column_value)(sqlite3_stmt*,int iCol);
+  void * (*commit_hook)(sqlite3*,int(*)(void*),void*);
+  int  (*complete)(const char*sql);
+  int  (*complete16)(const void*sql);
+  int  (*create_collation)(sqlite3*,const char*,int,void*,
+                           int(*)(void*,int,const void*,int,const void*));
+  int  (*create_collation16)(sqlite3*,const void*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*));
+  int  (*create_function)(sqlite3*,const char*,int,int,void*,
+                          void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xFinal)(sqlite3_context*));
+  int  (*create_function16)(sqlite3*,const void*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*));
+  int (*create_module)(sqlite3*,const char*,const sqlite3_module*,void*);
+  int  (*data_count)(sqlite3_stmt*pStmt);
+  sqlite3 * (*db_handle)(sqlite3_stmt*);
+  int (*declare_vtab)(sqlite3*,const char*);
+  int  (*enable_shared_cache)(int);
+  int  (*errcode)(sqlite3*db);
+  const char * (*errmsg)(sqlite3*);
+  const void * (*errmsg16)(sqlite3*);
+  int  (*exec)(sqlite3*,const char*,sqlite3_callback,void*,char**);
+  int  (*expired)(sqlite3_stmt*);
+  int  (*finalize)(sqlite3_stmt*pStmt);
+  void  (*free)(void*);
+  void  (*free_table)(char**result);
+  int  (*get_autocommit)(sqlite3*);
+  void * (*get_auxdata)(sqlite3_context*,int);
+  int  (*get_table)(sqlite3*,const char*,char***,int*,int*,char**);
+  int  (*global_recover)(void);
+  void  (*interruptx)(sqlite3*);
+  sqlite_int64  (*last_insert_rowid)(sqlite3*);
+  const char * (*libversion)(void);
+  int  (*libversion_number)(void);
+  void *(*malloc)(int);
+  char * (*mprintf)(const char*,...);
+  int  (*open)(const char*,sqlite3**);
+  int  (*open16)(const void*,sqlite3**);
+  int  (*prepare)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int  (*prepare16)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  void * (*profile)(sqlite3*,void(*)(void*,const char*,sqlite_uint64),void*);
+  void  (*progress_handler)(sqlite3*,int,int(*)(void*),void*);
+  void *(*realloc)(void*,int);
+  int  (*reset)(sqlite3_stmt*pStmt);
+  void  (*result_blob)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_double)(sqlite3_context*,double);
+  void  (*result_error)(sqlite3_context*,const char*,int);
+  void  (*result_error16)(sqlite3_context*,const void*,int);
+  void  (*result_int)(sqlite3_context*,int);
+  void  (*result_int64)(sqlite3_context*,sqlite_int64);
+  void  (*result_null)(sqlite3_context*);
+  void  (*result_text)(sqlite3_context*,const char*,int,void(*)(void*));
+  void  (*result_text16)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16be)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16le)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_value)(sqlite3_context*,sqlite3_value*);
+  void * (*rollback_hook)(sqlite3*,void(*)(void*),void*);
+  int  (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,
+                         const char*,const char*),void*);
+  void  (*set_auxdata)(sqlite3_context*,int,void*,void (*)(void*));
+  char * (*xsnprintf)(int,char*,const char*,...);
+  int  (*step)(sqlite3_stmt*);
+  int  (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,
+                                char const**,char const**,int*,int*,int*);
+  void  (*thread_cleanup)(void);
+  int  (*total_changes)(sqlite3*);
+  void * (*trace)(sqlite3*,void(*xTrace)(void*,const char*),void*);
+  int  (*transfer_bindings)(sqlite3_stmt*,sqlite3_stmt*);
+  void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,
+                                         sqlite_int64),void*);
+  void * (*user_data)(sqlite3_context*);
+  const void * (*value_blob)(sqlite3_value*);
+  int  (*value_bytes)(sqlite3_value*);
+  int  (*value_bytes16)(sqlite3_value*);
+  double  (*value_double)(sqlite3_value*);
+  int  (*value_int)(sqlite3_value*);
+  sqlite_int64  (*value_int64)(sqlite3_value*);
+  int  (*value_numeric_type)(sqlite3_value*);
+  const unsigned char * (*value_text)(sqlite3_value*);
+  const void * (*value_text16)(sqlite3_value*);
+  const void * (*value_text16be)(sqlite3_value*);
+  const void * (*value_text16le)(sqlite3_value*);
+  int  (*value_type)(sqlite3_value*);
+  char *(*vmprintf)(const char*,va_list);
+  /* Added ??? */
+  int (*overload_function)(sqlite3*, const char *zFuncName, int nArg);
+  /* Added by 3.3.13 */
+  int (*prepare_v2)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int (*prepare16_v2)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  int (*clear_bindings)(sqlite3_stmt*);
+  /* Added by 3.4.1 */
+  int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,
+                          void (*xDestroy)(void *));
+  /* Added by 3.5.0 */
+  int (*bind_zeroblob)(sqlite3_stmt*,int,int);
+  int (*blob_bytes)(sqlite3_blob*);
+  int (*blob_close)(sqlite3_blob*);
+  int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,
+                   int,sqlite3_blob**);
+  int (*blob_read)(sqlite3_blob*,void*,int,int);
+  int (*blob_write)(sqlite3_blob*,const void*,int,int);
+  int (*create_collation_v2)(sqlite3*,const char*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*),
+                             void(*)(void*));
+  int (*file_control)(sqlite3*,const char*,int,void*);
+  sqlite3_int64 (*memory_highwater)(int);
+  sqlite3_int64 (*memory_used)(void);
+  sqlite3_mutex *(*mutex_alloc)(int);
+  void (*mutex_enter)(sqlite3_mutex*);
+  void (*mutex_free)(sqlite3_mutex*);
+  void (*mutex_leave)(sqlite3_mutex*);
+  int (*mutex_try)(sqlite3_mutex*);
+  int (*open_v2)(const char*,sqlite3**,int,const char*);
+  int (*release_memory)(int);
+  void (*result_error_nomem)(sqlite3_context*);
+  void (*result_error_toobig)(sqlite3_context*);
+  int (*sleep)(int);
+  void (*soft_heap_limit)(int);
+  sqlite3_vfs *(*vfs_find)(const char*);
+  int (*vfs_register)(sqlite3_vfs*,int);
+  int (*vfs_unregister)(sqlite3_vfs*);
+  int (*xthreadsafe)(void);
+  void (*result_zeroblob)(sqlite3_context*,int);
+  void (*result_error_code)(sqlite3_context*,int);
+  int (*test_control)(int, ...);
+  void (*randomness)(int,void*);
+  sqlite3 *(*context_db_handle)(sqlite3_context*);
+  int (*extended_result_codes)(sqlite3*,int);
+  int (*limit)(sqlite3*,int,int);
+  sqlite3_stmt *(*next_stmt)(sqlite3*,sqlite3_stmt*);
+  const char *(*sql)(sqlite3_stmt*);
+  int (*status)(int,int*,int*,int);
+  int (*backup_finish)(sqlite3_backup*);
+  sqlite3_backup *(*backup_init)(sqlite3*,const char*,sqlite3*,const char*);
+  int (*backup_pagecount)(sqlite3_backup*);
+  int (*backup_remaining)(sqlite3_backup*);
+  int (*backup_step)(sqlite3_backup*,int);
+  const char *(*compileoption_get)(int);
+  int (*compileoption_used)(const char*);
+  int (*create_function_v2)(sqlite3*,const char*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void(*xDestroy)(void*));
+  int (*db_config)(sqlite3*,int,...);
+  sqlite3_mutex *(*db_mutex)(sqlite3*);
+  int (*db_status)(sqlite3*,int,int*,int*,int);
+  int (*extended_errcode)(sqlite3*);
+  void (*log)(int,const char*,...);
+  sqlite3_int64 (*soft_heap_limit64)(sqlite3_int64);
+  const char *(*sourceid)(void);
+  int (*stmt_status)(sqlite3_stmt*,int,int);
+  int (*strnicmp)(const char*,const char*,int);
+  int (*unlock_notify)(sqlite3*,void(*)(void**,int),void*);
+  int (*wal_autocheckpoint)(sqlite3*,int);
+  int (*wal_checkpoint)(sqlite3*,const char*);
+  void *(*wal_hook)(sqlite3*,int(*)(void*,sqlite3*,const char*,int),void*);
+  int (*blob_reopen)(sqlite3_blob*,sqlite3_int64);
+  int (*vtab_config)(sqlite3*,int op,...);
+  int (*vtab_on_conflict)(sqlite3*);
+  /* Version 3.7.16 and later */
+  int (*close_v2)(sqlite3*);
+  const char *(*db_filename)(sqlite3*,const char*);
+  int (*db_readonly)(sqlite3*,const char*);
+  int (*db_release_memory)(sqlite3*);
+  const char *(*errstr)(int);
+  int (*stmt_busy)(sqlite3_stmt*);
+  int (*stmt_readonly)(sqlite3_stmt*);
+  int (*stricmp)(const char*,const char*);
+  int (*uri_boolean)(const char*,const char*,int);
+  sqlite3_int64 (*uri_int64)(const char*,const char*,sqlite3_int64);
+  const char *(*uri_parameter)(const char*,const char*);
+  char *(*xvsnprintf)(int,char*,const char*,va_list);
+  int (*wal_checkpoint_v2)(sqlite3*,const char*,int,int*,int*);
+  /* Version 3.8.7 and later */
+  int (*auto_extension)(void(*)(void));
+  int (*bind_blob64)(sqlite3_stmt*,int,const void*,sqlite3_uint64,
+                     void(*)(void*));
+  int (*bind_text64)(sqlite3_stmt*,int,const char*,sqlite3_uint64,
+                      void(*)(void*),unsigned char);
+  int (*cancel_auto_extension)(void(*)(void));
+  int (*load_extension)(sqlite3*,const char*,const char*,char**);
+  void *(*malloc64)(sqlite3_uint64);
+  sqlite3_uint64 (*msize)(void*);
+  void *(*realloc64)(void*,sqlite3_uint64);
+  void (*reset_auto_extension)(void);
+  void (*result_blob64)(sqlite3_context*,const void*,sqlite3_uint64,
+                        void(*)(void*));
+  void (*result_text64)(sqlite3_context*,const char*,sqlite3_uint64,
+                         void(*)(void*), unsigned char);
+  int (*strglob)(const char*,const char*);
+  /* Version 3.8.11 and later */
+  sqlite3_value *(*value_dup)(const sqlite3_value*);
+  void (*value_free)(sqlite3_value*);
+  int (*result_zeroblob64)(sqlite3_context*,sqlite3_uint64);
+  int (*bind_zeroblob64)(sqlite3_stmt*, int, sqlite3_uint64);
+  /* Version 3.9.0 and later */
+  unsigned int (*value_subtype)(sqlite3_value*);
+  void (*result_subtype)(sqlite3_context*,unsigned int);
+  /* Version 3.10.0 and later */
+  int (*status64)(int,sqlite3_int64*,sqlite3_int64*,int);
+  int (*strlike)(const char*,const char*,unsigned int);
+  int (*db_cacheflush)(sqlite3*);
+  /* Version 3.12.0 and later */
+  int (*system_errno)(sqlite3*);
+  /* Version 3.14.0 and later */
+  int (*trace_v2)(sqlite3*,unsigned,int(*)(unsigned,void*,void*,void*),void*);
+  char *(*expanded_sql)(sqlite3_stmt*);
+  /* Version 3.18.0 and later */
+  void (*set_last_insert_rowid)(sqlite3*,sqlite3_int64);
+  /* Version 3.20.0 and later */
+  int (*prepare_v3)(sqlite3*,const char*,int,unsigned int,
+                    sqlite3_stmt**,const char**);
+  int (*prepare16_v3)(sqlite3*,const void*,int,unsigned int,
+                      sqlite3_stmt**,const void**);
+  int (*bind_pointer)(sqlite3_stmt*,int,void*,const char*,void(*)(void*));
+  void (*result_pointer)(sqlite3_context*,void*,const char*,void(*)(void*));
+  void *(*value_pointer)(sqlite3_value*,const char*);
+  int (*vtab_nochange)(sqlite3_context*);
+  int (*value_nochange)(sqlite3_value*);
+  const char *(*vtab_collation)(sqlite3_index_info*,int);
+  /* Version 3.24.0 and later */
+  int (*keyword_count)(void);
+  int (*keyword_name)(int,const char**,int*);
+  int (*keyword_check)(const char*,int);
+  sqlite3_str *(*str_new)(sqlite3*);
+  char *(*str_finish)(sqlite3_str*);
+  void (*str_appendf)(sqlite3_str*, const char *zFormat, ...);
+  void (*str_vappendf)(sqlite3_str*, const char *zFormat, va_list);
+  void (*str_append)(sqlite3_str*, const char *zIn, int N);
+  void (*str_appendall)(sqlite3_str*, const char *zIn);
+  void (*str_appendchar)(sqlite3_str*, int N, char C);
+  void (*str_reset)(sqlite3_str*);
+  int (*str_errcode)(sqlite3_str*);
+  int (*str_length)(sqlite3_str*);
+  char *(*str_value)(sqlite3_str*);
+  /* Version 3.25.0 and later */
+  int (*create_window_function)(sqlite3*,const char*,int,int,void*,
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void (*xValue)(sqlite3_context*),
+                            void (*xInv)(sqlite3_context*,int,sqlite3_value**),
+                            void(*xDestroy)(void*));
+  /* Version 3.26.0 and later */
+  const char *(*normalized_sql)(sqlite3_stmt*);
+  /* Version 3.28.0 and later */
+  int (*stmt_isexplain)(sqlite3_stmt*);
+  int (*value_frombind)(sqlite3_value*);
+  /* Version 3.30.0 and later */
+  int (*drop_modules)(sqlite3*,const char**);
+  /* Version 3.31.0 and later */
+  sqlite3_int64 (*hard_heap_limit64)(sqlite3_int64);
+  const char *(*uri_key)(const char*,int);
+  const char *(*filename_database)(const char*);
+  const char *(*filename_journal)(const char*);
+  const char *(*filename_wal)(const char*);
+  /* Version 3.32.0 and later */
+  const char *(*create_filename)(const char*,const char*,const char*,
+                           int,const char**);
+  void (*free_filename)(const char*);
+  sqlite3_file *(*database_file_object)(const char*);
+  /* Version 3.34.0 and later */
+  int (*txn_state)(sqlite3*,const char*);
+  /* Version 3.36.1 and later */
+  sqlite3_int64 (*changes64)(sqlite3*);
+  sqlite3_int64 (*total_changes64)(sqlite3*);
+  /* Version 3.37.0 and later */
+  int (*autovacuum_pages)(sqlite3*,
+     unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
+     void*, void(*)(void*));
+  /* Version 3.38.0 and later */
+  int (*error_offset)(sqlite3*);
+  int (*vtab_rhs_value)(sqlite3_index_info*,int,sqlite3_value**);
+  int (*vtab_distinct)(sqlite3_index_info*);
+  int (*vtab_in)(sqlite3_index_info*,int,int);
+  int (*vtab_in_first)(sqlite3_value*,sqlite3_value**);
+  int (*vtab_in_next)(sqlite3_value*,sqlite3_value**);
+  /* Version 3.39.0 and later */
+  int (*deserialize)(sqlite3*,const char*,unsigned char*,
+                     sqlite3_int64,sqlite3_int64,unsigned);
+  unsigned char *(*serialize)(sqlite3*,const char *,sqlite3_int64*,
+                              unsigned int);
+  const char *(*db_name)(sqlite3*,int);
+  /* Version 3.40.0 and later */
+  int (*value_encoding)(sqlite3_value*);
+  /* Version 3.41.0 and later */
+  int (*is_interrupted)(sqlite3*);
+  /* Version 3.43.0 and later */
+  int (*stmt_explain)(sqlite3_stmt*,int);
+  /* Version 3.44.0 and later */
+  void *(*get_clientdata)(sqlite3*,const char*);
+  int (*set_clientdata)(sqlite3*, const char*, void*, void(*)(void*));
+};
+
+/*
+** This is the function signature used for all extension entry points.  It
+** is also defined in the file "loadext.c".
+*/
+typedef int (*sqlite3_loadext_entry)(
+  sqlite3 *db,                       /* Handle to the database. */
+  char **pzErrMsg,                   /* Used to set error string on failure. */
+  const sqlite3_api_routines *pThunk /* Extension API function pointers. */
+);
+
+/*
+** The following macros redefine the API routines so that they are
+** redirected through the global sqlite3_api structure.
+**
+** This header file is also used by the loadext.c source file
+** (part of the main SQLite library - not an extension) so that
+** it can get access to the sqlite3_api_routines structure
+** definition.  But the main library does not want to redefine
+** the API.  So the redefinition macros are only valid if the
+** SQLITE_CORE macros is undefined.
+*/
+#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+#define sqlite3_aggregate_context      sqlite3_api->aggregate_context
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_aggregate_count        sqlite3_api->aggregate_count
+#endif
+#define sqlite3_bind_blob              sqlite3_api->bind_blob
+#define sqlite3_bind_double            sqlite3_api->bind_double
+#define sqlite3_bind_int               sqlite3_api->bind_int
+#define sqlite3_bind_int64             sqlite3_api->bind_int64
+#define sqlite3_bind_null              sqlite3_api->bind_null
+#define sqlite3_bind_parameter_count   sqlite3_api->bind_parameter_count
+#define sqlite3_bind_parameter_index   sqlite3_api->bind_parameter_index
+#define sqlite3_bind_parameter_name    sqlite3_api->bind_parameter_name
+#define sqlite3_bind_text              sqlite3_api->bind_text
+#define sqlite3_bind_text16            sqlite3_api->bind_text16
+#define sqlite3_bind_value             sqlite3_api->bind_value
+#define sqlite3_busy_handler           sqlite3_api->busy_handler
+#define sqlite3_busy_timeout           sqlite3_api->busy_timeout
+#define sqlite3_changes                sqlite3_api->changes
+#define sqlite3_close                  sqlite3_api->close
+#define sqlite3_collation_needed       sqlite3_api->collation_needed
+#define sqlite3_collation_needed16     sqlite3_api->collation_needed16
+#define sqlite3_column_blob            sqlite3_api->column_blob
+#define sqlite3_column_bytes           sqlite3_api->column_bytes
+#define sqlite3_column_bytes16         sqlite3_api->column_bytes16
+#define sqlite3_column_count           sqlite3_api->column_count
+#define sqlite3_column_database_name   sqlite3_api->column_database_name
+#define sqlite3_column_database_name16 sqlite3_api->column_database_name16
+#define sqlite3_column_decltype        sqlite3_api->column_decltype
+#define sqlite3_column_decltype16      sqlite3_api->column_decltype16
+#define sqlite3_column_double          sqlite3_api->column_double
+#define sqlite3_column_int             sqlite3_api->column_int
+#define sqlite3_column_int64           sqlite3_api->column_int64
+#define sqlite3_column_name            sqlite3_api->column_name
+#define sqlite3_column_name16          sqlite3_api->column_name16
+#define sqlite3_column_origin_name     sqlite3_api->column_origin_name
+#define sqlite3_column_origin_name16   sqlite3_api->column_origin_name16
+#define sqlite3_column_table_name      sqlite3_api->column_table_name
+#define sqlite3_column_table_name16    sqlite3_api->column_table_name16
+#define sqlite3_column_text            sqlite3_api->column_text
+#define sqlite3_column_text16          sqlite3_api->column_text16
+#define sqlite3_column_type            sqlite3_api->column_type
+#define sqlite3_column_value           sqlite3_api->column_value
+#define sqlite3_commit_hook            sqlite3_api->commit_hook
+#define sqlite3_complete               sqlite3_api->complete
+#define sqlite3_complete16             sqlite3_api->complete16
+#define sqlite3_create_collation       sqlite3_api->create_collation
+#define sqlite3_create_collation16     sqlite3_api->create_collation16
+#define sqlite3_create_function        sqlite3_api->create_function
+#define sqlite3_create_function16      sqlite3_api->create_function16
+#define sqlite3_create_module          sqlite3_api->create_module
+#define sqlite3_create_module_v2       sqlite3_api->create_module_v2
+#define sqlite3_data_count             sqlite3_api->data_count
+#define sqlite3_db_handle              sqlite3_api->db_handle
+#define sqlite3_declare_vtab           sqlite3_api->declare_vtab
+#define sqlite3_enable_shared_cache    sqlite3_api->enable_shared_cache
+#define sqlite3_errcode                sqlite3_api->errcode
+#define sqlite3_errmsg                 sqlite3_api->errmsg
+#define sqlite3_errmsg16               sqlite3_api->errmsg16
+#define sqlite3_exec                   sqlite3_api->exec
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_expired                sqlite3_api->expired
+#endif
+#define sqlite3_finalize               sqlite3_api->finalize
+#define sqlite3_free                   sqlite3_api->free
+#define sqlite3_free_table             sqlite3_api->free_table
+#define sqlite3_get_autocommit         sqlite3_api->get_autocommit
+#define sqlite3_get_auxdata            sqlite3_api->get_auxdata
+#define sqlite3_get_table              sqlite3_api->get_table
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_global_recover         sqlite3_api->global_recover
+#endif
+#define sqlite3_interrupt              sqlite3_api->interruptx
+#define sqlite3_last_insert_rowid      sqlite3_api->last_insert_rowid
+#define sqlite3_libversion             sqlite3_api->libversion
+#define sqlite3_libversion_number      sqlite3_api->libversion_number
+#define sqlite3_malloc                 sqlite3_api->malloc
+#define sqlite3_mprintf                sqlite3_api->mprintf
+#define sqlite3_open                   sqlite3_api->open
+#define sqlite3_open16                 sqlite3_api->open16
+#define sqlite3_prepare                sqlite3_api->prepare
+#define sqlite3_prepare16              sqlite3_api->prepare16
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_profile                sqlite3_api->profile
+#define sqlite3_progress_handler       sqlite3_api->progress_handler
+#define sqlite3_realloc                sqlite3_api->realloc
+#define sqlite3_reset                  sqlite3_api->reset
+#define sqlite3_result_blob            sqlite3_api->result_blob
+#define sqlite3_result_double          sqlite3_api->result_double
+#define sqlite3_result_error           sqlite3_api->result_error
+#define sqlite3_result_error16         sqlite3_api->result_error16
+#define sqlite3_result_int             sqlite3_api->result_int
+#define sqlite3_result_int64           sqlite3_api->result_int64
+#define sqlite3_result_null            sqlite3_api->result_null
+#define sqlite3_result_text            sqlite3_api->result_text
+#define sqlite3_result_text16          sqlite3_api->result_text16
+#define sqlite3_result_text16be        sqlite3_api->result_text16be
+#define sqlite3_result_text16le        sqlite3_api->result_text16le
+#define sqlite3_result_value           sqlite3_api->result_value
+#define sqlite3_rollback_hook          sqlite3_api->rollback_hook
+#define sqlite3_set_authorizer         sqlite3_api->set_authorizer
+#define sqlite3_set_auxdata            sqlite3_api->set_auxdata
+#define sqlite3_snprintf               sqlite3_api->xsnprintf
+#define sqlite3_step                   sqlite3_api->step
+#define sqlite3_table_column_metadata  sqlite3_api->table_column_metadata
+#define sqlite3_thread_cleanup         sqlite3_api->thread_cleanup
+#define sqlite3_total_changes          sqlite3_api->total_changes
+#define sqlite3_trace                  sqlite3_api->trace
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_transfer_bindings      sqlite3_api->transfer_bindings
+#endif
+#define sqlite3_update_hook            sqlite3_api->update_hook
+#define sqlite3_user_data              sqlite3_api->user_data
+#define sqlite3_value_blob             sqlite3_api->value_blob
+#define sqlite3_value_bytes            sqlite3_api->value_bytes
+#define sqlite3_value_bytes16          sqlite3_api->value_bytes16
+#define sqlite3_value_double           sqlite3_api->value_double
+#define sqlite3_value_int              sqlite3_api->value_int
+#define sqlite3_value_int64            sqlite3_api->value_int64
+#define sqlite3_value_numeric_type     sqlite3_api->value_numeric_type
+#define sqlite3_value_text             sqlite3_api->value_text
+#define sqlite3_value_text16           sqlite3_api->value_text16
+#define sqlite3_value_text16be         sqlite3_api->value_text16be
+#define sqlite3_value_text16le         sqlite3_api->value_text16le
+#define sqlite3_value_type             sqlite3_api->value_type
+#define sqlite3_vmprintf               sqlite3_api->vmprintf
+#define sqlite3_vsnprintf              sqlite3_api->xvsnprintf
+#define sqlite3_overload_function      sqlite3_api->overload_function
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_clear_bindings         sqlite3_api->clear_bindings
+#define sqlite3_bind_zeroblob          sqlite3_api->bind_zeroblob
+#define sqlite3_blob_bytes             sqlite3_api->blob_bytes
+#define sqlite3_blob_close             sqlite3_api->blob_close
+#define sqlite3_blob_open              sqlite3_api->blob_open
+#define sqlite3_blob_read              sqlite3_api->blob_read
+#define sqlite3_blob_write             sqlite3_api->blob_write
+#define sqlite3_create_collation_v2    sqlite3_api->create_collation_v2
+#define sqlite3_file_control           sqlite3_api->file_control
+#define sqlite3_memory_highwater       sqlite3_api->memory_highwater
+#define sqlite3_memory_used            sqlite3_api->memory_used
+#define sqlite3_mutex_alloc            sqlite3_api->mutex_alloc
+#define sqlite3_mutex_enter            sqlite3_api->mutex_enter
+#define sqlite3_mutex_free             sqlite3_api->mutex_free
+#define sqlite3_mutex_leave            sqlite3_api->mutex_leave
+#define sqlite3_mutex_try              sqlite3_api->mutex_try
+#define sqlite3_open_v2                sqlite3_api->open_v2
+#define sqlite3_release_memory         sqlite3_api->release_memory
+#define sqlite3_result_error_nomem     sqlite3_api->result_error_nomem
+#define sqlite3_result_error_toobig    sqlite3_api->result_error_toobig
+#define sqlite3_sleep                  sqlite3_api->sleep
+#define sqlite3_soft_heap_limit        sqlite3_api->soft_heap_limit
+#define sqlite3_vfs_find               sqlite3_api->vfs_find
+#define sqlite3_vfs_register           sqlite3_api->vfs_register
+#define sqlite3_vfs_unregister         sqlite3_api->vfs_unregister
+#define sqlite3_threadsafe             sqlite3_api->xthreadsafe
+#define sqlite3_result_zeroblob        sqlite3_api->result_zeroblob
+#define sqlite3_result_error_code      sqlite3_api->result_error_code
+#define sqlite3_test_control           sqlite3_api->test_control
+#define sqlite3_randomness             sqlite3_api->randomness
+#define sqlite3_context_db_handle      sqlite3_api->context_db_handle
+#define sqlite3_extended_result_codes  sqlite3_api->extended_result_codes
+#define sqlite3_limit                  sqlite3_api->limit
+#define sqlite3_next_stmt              sqlite3_api->next_stmt
+#define sqlite3_sql                    sqlite3_api->sql
+#define sqlite3_status                 sqlite3_api->status
+#define sqlite3_backup_finish          sqlite3_api->backup_finish
+#define sqlite3_backup_init            sqlite3_api->backup_init
+#define sqlite3_backup_pagecount       sqlite3_api->backup_pagecount
+#define sqlite3_backup_remaining       sqlite3_api->backup_remaining
+#define sqlite3_backup_step            sqlite3_api->backup_step
+#define sqlite3_compileoption_get      sqlite3_api->compileoption_get
+#define sqlite3_compileoption_used     sqlite3_api->compileoption_used
+#define sqlite3_create_function_v2     sqlite3_api->create_function_v2
+#define sqlite3_db_config              sqlite3_api->db_config
+#define sqlite3_db_mutex               sqlite3_api->db_mutex
+#define sqlite3_db_status              sqlite3_api->db_status
+#define sqlite3_extended_errcode       sqlite3_api->extended_errcode
+#define sqlite3_log                    sqlite3_api->log
+#define sqlite3_soft_heap_limit64      sqlite3_api->soft_heap_limit64
+#define sqlite3_sourceid               sqlite3_api->sourceid
+#define sqlite3_stmt_status            sqlite3_api->stmt_status
+#define sqlite3_strnicmp               sqlite3_api->strnicmp
+#define sqlite3_unlock_notify          sqlite3_api->unlock_notify
+#define sqlite3_wal_autocheckpoint     sqlite3_api->wal_autocheckpoint
+#define sqlite3_wal_checkpoint         sqlite3_api->wal_checkpoint
+#define sqlite3_wal_hook               sqlite3_api->wal_hook
+#define sqlite3_blob_reopen            sqlite3_api->blob_reopen
+#define sqlite3_vtab_config            sqlite3_api->vtab_config
+#define sqlite3_vtab_on_conflict       sqlite3_api->vtab_on_conflict
+/* Version 3.7.16 and later */
+#define sqlite3_close_v2               sqlite3_api->close_v2
+#define sqlite3_db_filename            sqlite3_api->db_filename
+#define sqlite3_db_readonly            sqlite3_api->db_readonly
+#define sqlite3_db_release_memory      sqlite3_api->db_release_memory
+#define sqlite3_errstr                 sqlite3_api->errstr
+#define sqlite3_stmt_busy              sqlite3_api->stmt_busy
+#define sqlite3_stmt_readonly          sqlite3_api->stmt_readonly
+#define sqlite3_stricmp                sqlite3_api->stricmp
+#define sqlite3_uri_boolean            sqlite3_api->uri_boolean
+#define sqlite3_uri_int64              sqlite3_api->uri_int64
+#define sqlite3_uri_parameter          sqlite3_api->uri_parameter
+#define sqlite3_uri_vsnprintf          sqlite3_api->xvsnprintf
+#define sqlite3_wal_checkpoint_v2      sqlite3_api->wal_checkpoint_v2
+/* Version 3.8.7 and later */
+#define sqlite3_auto_extension         sqlite3_api->auto_extension
+#define sqlite3_bind_blob64            sqlite3_api->bind_blob64
+#define sqlite3_bind_text64            sqlite3_api->bind_text64
+#define sqlite3_cancel_auto_extension  sqlite3_api->cancel_auto_extension
+#define sqlite3_load_extension         sqlite3_api->load_extension
+#define sqlite3_malloc64               sqlite3_api->malloc64
+#define sqlite3_msize                  sqlite3_api->msize
+#define sqlite3_realloc64              sqlite3_api->realloc64
+#define sqlite3_reset_auto_extension   sqlite3_api->reset_auto_extension
+#define sqlite3_result_blob64          sqlite3_api->result_blob64
+#define sqlite3_result_text64          sqlite3_api->result_text64
+#define sqlite3_strglob                sqlite3_api->strglob
+/* Version 3.8.11 and later */
+#define sqlite3_value_dup              sqlite3_api->value_dup
+#define sqlite3_value_free             sqlite3_api->value_free
+#define sqlite3_result_zeroblob64      sqlite3_api->result_zeroblob64
+#define sqlite3_bind_zeroblob64        sqlite3_api->bind_zeroblob64
+/* Version 3.9.0 and later */
+#define sqlite3_value_subtype          sqlite3_api->value_subtype
+#define sqlite3_result_subtype         sqlite3_api->result_subtype
+/* Version 3.10.0 and later */
+#define sqlite3_status64               sqlite3_api->status64
+#define sqlite3_strlike                sqlite3_api->strlike
+#define sqlite3_db_cacheflush          sqlite3_api->db_cacheflush
+/* Version 3.12.0 and later */
+#define sqlite3_system_errno           sqlite3_api->system_errno
+/* Version 3.14.0 and later */
+#define sqlite3_trace_v2               sqlite3_api->trace_v2
+#define sqlite3_expanded_sql           sqlite3_api->expanded_sql
+/* Version 3.18.0 and later */
+#define sqlite3_set_last_insert_rowid  sqlite3_api->set_last_insert_rowid
+/* Version 3.20.0 and later */
+#define sqlite3_prepare_v3             sqlite3_api->prepare_v3
+#define sqlite3_prepare16_v3           sqlite3_api->prepare16_v3
+#define sqlite3_bind_pointer           sqlite3_api->bind_pointer
+#define sqlite3_result_pointer         sqlite3_api->result_pointer
+#define sqlite3_value_pointer          sqlite3_api->value_pointer
+/* Version 3.22.0 and later */
+#define sqlite3_vtab_nochange          sqlite3_api->vtab_nochange
+#define sqlite3_value_nochange         sqlite3_api->value_nochange
+#define sqlite3_vtab_collation         sqlite3_api->vtab_collation
+/* Version 3.24.0 and later */
+#define sqlite3_keyword_count          sqlite3_api->keyword_count
+#define sqlite3_keyword_name           sqlite3_api->keyword_name
+#define sqlite3_keyword_check          sqlite3_api->keyword_check
+#define sqlite3_str_new                sqlite3_api->str_new
+#define sqlite3_str_finish             sqlite3_api->str_finish
+#define sqlite3_str_appendf            sqlite3_api->str_appendf
+#define sqlite3_str_vappendf           sqlite3_api->str_vappendf
+#define sqlite3_str_append             sqlite3_api->str_append
+#define sqlite3_str_appendall          sqlite3_api->str_appendall
+#define sqlite3_str_appendchar         sqlite3_api->str_appendchar
+#define sqlite3_str_reset              sqlite3_api->str_reset
+#define sqlite3_str_errcode            sqlite3_api->str_errcode
+#define sqlite3_str_length             sqlite3_api->str_length
+#define sqlite3_str_value              sqlite3_api->str_value
+/* Version 3.25.0 and later */
+#define sqlite3_create_window_function sqlite3_api->create_window_function
+/* Version 3.26.0 and later */
+#define sqlite3_normalized_sql         sqlite3_api->normalized_sql
+/* Version 3.28.0 and later */
+#define sqlite3_stmt_isexplain         sqlite3_api->stmt_isexplain
+#define sqlite3_value_frombind         sqlite3_api->value_frombind
+/* Version 3.30.0 and later */
+#define sqlite3_drop_modules           sqlite3_api->drop_modules
+/* Version 3.31.0 and later */
+#define sqlite3_hard_heap_limit64      sqlite3_api->hard_heap_limit64
+#define sqlite3_uri_key                sqlite3_api->uri_key
+#define sqlite3_filename_database      sqlite3_api->filename_database
+#define sqlite3_filename_journal       sqlite3_api->filename_journal
+#define sqlite3_filename_wal           sqlite3_api->filename_wal
+/* Version 3.32.0 and later */
+#define sqlite3_create_filename        sqlite3_api->create_filename
+#define sqlite3_free_filename          sqlite3_api->free_filename
+#define sqlite3_database_file_object   sqlite3_api->database_file_object
+/* Version 3.34.0 and later */
+#define sqlite3_txn_state              sqlite3_api->txn_state
+/* Version 3.36.1 and later */
+#define sqlite3_changes64              sqlite3_api->changes64
+#define sqlite3_total_changes64        sqlite3_api->total_changes64
+/* Version 3.37.0 and later */
+#define sqlite3_autovacuum_pages       sqlite3_api->autovacuum_pages
+/* Version 3.38.0 and later */
+#define sqlite3_error_offset           sqlite3_api->error_offset
+#define sqlite3_vtab_rhs_value         sqlite3_api->vtab_rhs_value
+#define sqlite3_vtab_distinct          sqlite3_api->vtab_distinct
+#define sqlite3_vtab_in                sqlite3_api->vtab_in
+#define sqlite3_vtab_in_first          sqlite3_api->vtab_in_first
+#define sqlite3_vtab_in_next           sqlite3_api->vtab_in_next
+/* Version 3.39.0 and later */
+#ifndef SQLITE_OMIT_DESERIALIZE
+#define sqlite3_deserialize            sqlite3_api->deserialize
+#define sqlite3_serialize              sqlite3_api->serialize
+#endif
+#define sqlite3_db_name                sqlite3_api->db_name
+/* Version 3.40.0 and later */
+#define sqlite3_value_encoding         sqlite3_api->value_encoding
+/* Version 3.41.0 and later */
+#define sqlite3_is_interrupted         sqlite3_api->is_interrupted
+/* Version 3.43.0 and later */
+#define sqlite3_stmt_explain           sqlite3_api->stmt_explain
+/* Version 3.44.0 and later */
+#define sqlite3_get_clientdata         sqlite3_api->get_clientdata
+#define sqlite3_set_clientdata         sqlite3_api->set_clientdata
+#endif /* !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION) */
+
+#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  /* This case when the file really is being compiled as a loadable 
+  ** extension */
+# define SQLITE_EXTENSION_INIT1     const sqlite3_api_routines *sqlite3_api=0;
+# define SQLITE_EXTENSION_INIT2(v)  sqlite3_api=v;
+# define SQLITE_EXTENSION_INIT3     \
+    extern const sqlite3_api_routines *sqlite3_api;
+#else
+  /* This case when the file is being statically linked into the 
+  ** application */
+# define SQLITE_EXTENSION_INIT1     /*no-op*/
+# define SQLITE_EXTENSION_INIT2(v)  (void)v; /* unused parameter */
+# define SQLITE_EXTENSION_INIT3     /*no-op*/
+#endif
+
+#endif /* SQLITE3EXT_H */
diff --git a/server/node_modules/better-sqlite3/build/Release/sqlite3.a b/server/node_modules/better-sqlite3/build/Release/sqlite3.a
new file mode 100644
index 0000000..89b4dbf
Binary files /dev/null and b/server/node_modules/better-sqlite3/build/Release/sqlite3.a differ
diff --git a/server/node_modules/better-sqlite3/build/Release/test_extension.node b/server/node_modules/better-sqlite3/build/Release/test_extension.node
new file mode 100755
index 0000000..4593d9d
Binary files /dev/null and b/server/node_modules/better-sqlite3/build/Release/test_extension.node differ
diff --git a/server/node_modules/better-sqlite3/build/better_sqlite3.target.mk b/server/node_modules/better-sqlite3/build/better_sqlite3.target.mk
new file mode 100644
index 0000000..f282e19
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/better_sqlite3.target.mk
@@ -0,0 +1,174 @@
+# This file is generated by gyp; do not edit.
+
+TOOLSET := target
+TARGET := better_sqlite3
+DEFS_Debug := \
+	'-DNODE_GYP_MODULE_NAME=better_sqlite3' \
+	'-DUSING_UV_SHARED=1' \
+	'-DUSING_V8_SHARED=1' \
+	'-DV8_DEPRECATION_WARNINGS=1' \
+	'-D_GLIBCXX_USE_CXX11_ABI=1' \
+	'-D_FILE_OFFSET_BITS=64' \
+	'-D_LARGEFILE_SOURCE' \
+	'-D__STDC_FORMAT_MACROS' \
+	'-DBUILDING_NODE_EXTENSION' \
+	'-DDEBUG' \
+	'-D_DEBUG' \
+	'-DSQLITE_DEBUG' \
+	'-DSQLITE_MEMDEBUG' \
+	'-DSQLITE_ENABLE_API_ARMOR' \
+	'-DSQLITE_WIN32_MALLOC_VALIDATE'
+
+# Flags passed to all source files.
+CFLAGS_Debug := \
+	-fPIC \
+	-pthread \
+	-Wall \
+	-Wextra \
+	-Wno-unused-parameter \
+	-fPIC \
+	-m64 \
+	-g \
+	-O0 \
+	-O0
+
+# Flags passed to only C files.
+CFLAGS_C_Debug :=
+
+# Flags passed to only C++ files.
+CFLAGS_CC_Debug := \
+	-fno-rtti \
+	-fno-exceptions \
+	-fno-strict-aliasing \
+	-std=gnu++20 \
+	-std=c++20
+
+INCS_Debug := \
+	-I/home/fahed/.cache/node-gyp/25.5.0/include/node \
+	-I/home/fahed/.cache/node-gyp/25.5.0/src \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/config \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/openssl/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/uv/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/zlib \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/v8/include \
+	-I$(obj)/gen/sqlite3
+
+DEFS_Release := \
+	'-DNODE_GYP_MODULE_NAME=better_sqlite3' \
+	'-DUSING_UV_SHARED=1' \
+	'-DUSING_V8_SHARED=1' \
+	'-DV8_DEPRECATION_WARNINGS=1' \
+	'-D_GLIBCXX_USE_CXX11_ABI=1' \
+	'-D_FILE_OFFSET_BITS=64' \
+	'-D_LARGEFILE_SOURCE' \
+	'-D__STDC_FORMAT_MACROS' \
+	'-DBUILDING_NODE_EXTENSION' \
+	'-DNDEBUG'
+
+# Flags passed to all source files.
+CFLAGS_Release := \
+	-fPIC \
+	-pthread \
+	-Wall \
+	-Wextra \
+	-Wno-unused-parameter \
+	-fPIC \
+	-m64 \
+	-O3 \
+	-O3 \
+	-fno-omit-frame-pointer
+
+# Flags passed to only C files.
+CFLAGS_C_Release :=
+
+# Flags passed to only C++ files.
+CFLAGS_CC_Release := \
+	-fno-rtti \
+	-fno-exceptions \
+	-fno-strict-aliasing \
+	-std=gnu++20 \
+	-std=c++20
+
+INCS_Release := \
+	-I/home/fahed/.cache/node-gyp/25.5.0/include/node \
+	-I/home/fahed/.cache/node-gyp/25.5.0/src \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/config \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/openssl/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/uv/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/zlib \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/v8/include \
+	-I$(obj)/gen/sqlite3
+
+OBJS := \
+	$(obj).target/$(TARGET)/src/better_sqlite3.o
+
+# Add to the list of files we specially track dependencies for.
+all_deps += $(OBJS)
+
+# Make sure our dependencies are built before any of us.
+$(OBJS): | $(builddir)/sqlite3.a $(obj).target/deps/locate_sqlite3.stamp $(obj).target/deps/sqlite3.a
+
+# CFLAGS et al overrides must be target-local.
+# See "Target-specific Variable Values" in the GNU Make manual.
+$(OBJS): TOOLSET := $(TOOLSET)
+$(OBJS): GYP_CFLAGS := $(DEFS_$(BUILDTYPE)) $(INCS_$(BUILDTYPE))  $(CFLAGS_$(BUILDTYPE)) $(CFLAGS_C_$(BUILDTYPE))
+$(OBJS): GYP_CXXFLAGS := $(DEFS_$(BUILDTYPE)) $(INCS_$(BUILDTYPE))  $(CFLAGS_$(BUILDTYPE)) $(CFLAGS_CC_$(BUILDTYPE))
+
+# Suffix rules, putting all outputs into $(obj).
+
+$(obj).$(TOOLSET)/$(TARGET)/%.o: $(srcdir)/%.cpp FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+
+# Try building from generated source, too.
+
+$(obj).$(TOOLSET)/$(TARGET)/%.o: $(obj).$(TOOLSET)/%.cpp FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+
+$(obj).$(TOOLSET)/$(TARGET)/%.o: $(obj)/%.cpp FORCE_DO_CMD
+	@$(call do_cmd,cxx,1)
+
+# End of this set of suffix rules
+### Rules for final target.
+LDFLAGS_Debug := \
+	-pthread \
+	-rdynamic \
+	-fPIC \
+	-Wl,-Bsymbolic \
+	-Wl,--exclude-libs,ALL \
+	-m64
+
+LDFLAGS_Release := \
+	-pthread \
+	-rdynamic \
+	-fPIC \
+	-Wl,-Bsymbolic \
+	-Wl,--exclude-libs,ALL \
+	-m64
+
+LIBS :=
+
+$(obj).target/better_sqlite3.node: GYP_LDFLAGS := $(LDFLAGS_$(BUILDTYPE))
+$(obj).target/better_sqlite3.node: LIBS := $(LIBS)
+$(obj).target/better_sqlite3.node: TOOLSET := $(TOOLSET)
+$(obj).target/better_sqlite3.node: $(OBJS) $(obj).target/deps/sqlite3.a FORCE_DO_CMD
+	$(call do_cmd,solink_module)
+
+all_deps += $(obj).target/better_sqlite3.node
+# Add target alias
+.PHONY: better_sqlite3
+better_sqlite3: $(builddir)/better_sqlite3.node
+
+# Copy this to the executable output path.
+$(builddir)/better_sqlite3.node: TOOLSET := $(TOOLSET)
+$(builddir)/better_sqlite3.node: $(obj).target/better_sqlite3.node FORCE_DO_CMD
+	$(call do_cmd,copy)
+
+all_deps += $(builddir)/better_sqlite3.node
+# Short alias for building this executable.
+.PHONY: better_sqlite3.node
+better_sqlite3.node: $(obj).target/better_sqlite3.node $(builddir)/better_sqlite3.node
+
+# Add executable to "all" target.
+.PHONY: all
+all: $(builddir)/better_sqlite3.node
+
diff --git a/server/node_modules/better-sqlite3/build/binding.Makefile b/server/node_modules/better-sqlite3/build/binding.Makefile
new file mode 100644
index 0000000..267f19f
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/binding.Makefile
@@ -0,0 +1,6 @@
+# This file is generated by gyp; do not edit.
+
+export builddir_name ?= ./build/.
+.PHONY: all
+all:
+	$(MAKE) test_extension better_sqlite3
diff --git a/server/node_modules/better-sqlite3/build/config.gypi b/server/node_modules/better-sqlite3/build/config.gypi
new file mode 100644
index 0000000..4a42c1f
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/config.gypi
@@ -0,0 +1,539 @@
+# Do not edit. File was generated by node-gyp's "configure" step
+{
+  "variables": {
+    "use_ccache_win": 0,
+    "clang": 0,
+    "llvm_version": "0.0",
+    "node_prefix": "/home/linuxbrew/.linuxbrew/Cellar/node/25.5.0",
+    "node_install_npm": "false",
+    "node_install_corepack": "false",
+    "control_flow_guard": "false",
+    "node_use_amaro": "true",
+    "debug_node": "false",
+    "debug_symbols": "false",
+    "build_type%": "Release",
+    "error_on_warn": "false",
+    "suppress_all_error_on_warn": "false",
+    "use_prefix_to_find_headers": "false",
+    "host_arch": "x64",
+    "target_arch": "x64",
+    "node_byteorder": "little",
+    "want_separate_host_toolset": 0,
+    "node_use_node_snapshot": "false",
+    "node_use_node_code_cache": "false",
+    "node_write_snapshot_as_array_literals": "false",
+    "node_enable_v8_vtunejit": "false",
+    "enable_pgo_generate": "false",
+    "enable_pgo_use": "false",
+    "enable_lto": "false",
+    "single_executable_application": "true",
+    "node_use_lief": "true",
+    "node_with_ltcg": "false",
+    "node_tag": "",
+    "node_release_urlbase": "",
+    "node_debug_lib": "false",
+    "debug_nghttp2": "false",
+    "node_no_browser_globals": "false",
+    "node_shared": "true",
+    "libdir": "lib",
+    "node_module_version": 141,
+    "shlib_suffix": "so.141",
+    "asan": 0,
+    "ubsan": 0,
+    "coverage": "false",
+    "node_target_type": "shared_library",
+    "node_library_files": [
+      "lib/_http_agent.js",
+      "lib/_http_client.js",
+      "lib/_http_common.js",
+      "lib/_http_incoming.js",
+      "lib/_http_outgoing.js",
+      "lib/_http_server.js",
+      "lib/_stream_duplex.js",
+      "lib/_stream_passthrough.js",
+      "lib/_stream_readable.js",
+      "lib/_stream_transform.js",
+      "lib/_stream_wrap.js",
+      "lib/_stream_writable.js",
+      "lib/_tls_common.js",
+      "lib/_tls_wrap.js",
+      "lib/assert.js",
+      "lib/assert/strict.js",
+      "lib/async_hooks.js",
+      "lib/buffer.js",
+      "lib/child_process.js",
+      "lib/cluster.js",
+      "lib/console.js",
+      "lib/constants.js",
+      "lib/crypto.js",
+      "lib/dgram.js",
+      "lib/diagnostics_channel.js",
+      "lib/dns.js",
+      "lib/dns/promises.js",
+      "lib/domain.js",
+      "lib/events.js",
+      "lib/fs.js",
+      "lib/fs/promises.js",
+      "lib/http.js",
+      "lib/http2.js",
+      "lib/https.js",
+      "lib/inspector.js",
+      "lib/inspector/promises.js",
+      "lib/internal/abort_controller.js",
+      "lib/internal/assert.js",
+      "lib/internal/assert/assertion_error.js",
+      "lib/internal/assert/myers_diff.js",
+      "lib/internal/assert/utils.js",
+      "lib/internal/async_context_frame.js",
+      "lib/internal/async_hooks.js",
+      "lib/internal/async_local_storage/async_context_frame.js",
+      "lib/internal/async_local_storage/async_hooks.js",
+      "lib/internal/blob.js",
+      "lib/internal/blocklist.js",
+      "lib/internal/bootstrap/node.js",
+      "lib/internal/bootstrap/realm.js",
+      "lib/internal/bootstrap/shadow_realm.js",
+      "lib/internal/bootstrap/switches/does_not_own_process_state.js",
+      "lib/internal/bootstrap/switches/does_own_process_state.js",
+      "lib/internal/bootstrap/switches/is_main_thread.js",
+      "lib/internal/bootstrap/switches/is_not_main_thread.js",
+      "lib/internal/bootstrap/web/exposed-wildcard.js",
+      "lib/internal/bootstrap/web/exposed-window-or-worker.js",
+      "lib/internal/buffer.js",
+      "lib/internal/child_process.js",
+      "lib/internal/child_process/serialization.js",
+      "lib/internal/cli_table.js",
+      "lib/internal/cluster/child.js",
+      "lib/internal/cluster/primary.js",
+      "lib/internal/cluster/round_robin_handle.js",
+      "lib/internal/cluster/shared_handle.js",
+      "lib/internal/cluster/utils.js",
+      "lib/internal/cluster/worker.js",
+      "lib/internal/console/constructor.js",
+      "lib/internal/console/global.js",
+      "lib/internal/constants.js",
+      "lib/internal/crypto/aes.js",
+      "lib/internal/crypto/argon2.js",
+      "lib/internal/crypto/certificate.js",
+      "lib/internal/crypto/cfrg.js",
+      "lib/internal/crypto/chacha20_poly1305.js",
+      "lib/internal/crypto/cipher.js",
+      "lib/internal/crypto/diffiehellman.js",
+      "lib/internal/crypto/ec.js",
+      "lib/internal/crypto/hash.js",
+      "lib/internal/crypto/hashnames.js",
+      "lib/internal/crypto/hkdf.js",
+      "lib/internal/crypto/kem.js",
+      "lib/internal/crypto/keygen.js",
+      "lib/internal/crypto/keys.js",
+      "lib/internal/crypto/mac.js",
+      "lib/internal/crypto/ml_dsa.js",
+      "lib/internal/crypto/ml_kem.js",
+      "lib/internal/crypto/pbkdf2.js",
+      "lib/internal/crypto/random.js",
+      "lib/internal/crypto/rsa.js",
+      "lib/internal/crypto/scrypt.js",
+      "lib/internal/crypto/sig.js",
+      "lib/internal/crypto/util.js",
+      "lib/internal/crypto/webcrypto.js",
+      "lib/internal/crypto/webidl.js",
+      "lib/internal/crypto/x509.js",
+      "lib/internal/data_url.js",
+      "lib/internal/debugger/inspect.js",
+      "lib/internal/debugger/inspect_client.js",
+      "lib/internal/debugger/inspect_repl.js",
+      "lib/internal/dgram.js",
+      "lib/internal/dns/callback_resolver.js",
+      "lib/internal/dns/promises.js",
+      "lib/internal/dns/utils.js",
+      "lib/internal/encoding.js",
+      "lib/internal/encoding/single-byte.js",
+      "lib/internal/error_serdes.js",
+      "lib/internal/errors.js",
+      "lib/internal/errors/error_source.js",
+      "lib/internal/event_target.js",
+      "lib/internal/events/abort_listener.js",
+      "lib/internal/events/symbols.js",
+      "lib/internal/file.js",
+      "lib/internal/fixed_queue.js",
+      "lib/internal/freelist.js",
+      "lib/internal/freeze_intrinsics.js",
+      "lib/internal/fs/cp/cp-sync.js",
+      "lib/internal/fs/cp/cp.js",
+      "lib/internal/fs/dir.js",
+      "lib/internal/fs/glob.js",
+      "lib/internal/fs/promises.js",
+      "lib/internal/fs/read/context.js",
+      "lib/internal/fs/recursive_watch.js",
+      "lib/internal/fs/rimraf.js",
+      "lib/internal/fs/streams.js",
+      "lib/internal/fs/sync_write_stream.js",
+      "lib/internal/fs/utils.js",
+      "lib/internal/fs/watchers.js",
+      "lib/internal/heap_utils.js",
+      "lib/internal/histogram.js",
+      "lib/internal/http.js",
+      "lib/internal/http2/compat.js",
+      "lib/internal/http2/core.js",
+      "lib/internal/http2/util.js",
+      "lib/internal/inspector/network.js",
+      "lib/internal/inspector/network_http.js",
+      "lib/internal/inspector/network_http2.js",
+      "lib/internal/inspector/network_resources.js",
+      "lib/internal/inspector/network_undici.js",
+      "lib/internal/inspector_async_hook.js",
+      "lib/internal/inspector_network_tracking.js",
+      "lib/internal/js_stream_socket.js",
+      "lib/internal/legacy/processbinding.js",
+      "lib/internal/linkedlist.js",
+      "lib/internal/locks.js",
+      "lib/internal/main/check_syntax.js",
+      "lib/internal/main/embedding.js",
+      "lib/internal/main/eval_stdin.js",
+      "lib/internal/main/eval_string.js",
+      "lib/internal/main/inspect.js",
+      "lib/internal/main/mksnapshot.js",
+      "lib/internal/main/print_help.js",
+      "lib/internal/main/prof_process.js",
+      "lib/internal/main/repl.js",
+      "lib/internal/main/run_main_module.js",
+      "lib/internal/main/test_runner.js",
+      "lib/internal/main/watch_mode.js",
+      "lib/internal/main/worker_thread.js",
+      "lib/internal/mime.js",
+      "lib/internal/modules/cjs/loader.js",
+      "lib/internal/modules/customization_hooks.js",
+      "lib/internal/modules/esm/assert.js",
+      "lib/internal/modules/esm/create_dynamic_module.js",
+      "lib/internal/modules/esm/formats.js",
+      "lib/internal/modules/esm/get_format.js",
+      "lib/internal/modules/esm/hooks.js",
+      "lib/internal/modules/esm/load.js",
+      "lib/internal/modules/esm/loader.js",
+      "lib/internal/modules/esm/module_job.js",
+      "lib/internal/modules/esm/module_map.js",
+      "lib/internal/modules/esm/resolve.js",
+      "lib/internal/modules/esm/shared_constants.js",
+      "lib/internal/modules/esm/translators.js",
+      "lib/internal/modules/esm/utils.js",
+      "lib/internal/modules/esm/worker.js",
+      "lib/internal/modules/helpers.js",
+      "lib/internal/modules/package_json_reader.js",
+      "lib/internal/modules/run_main.js",
+      "lib/internal/modules/typescript.js",
+      "lib/internal/navigator.js",
+      "lib/internal/net.js",
+      "lib/internal/options.js",
+      "lib/internal/per_context/domexception.js",
+      "lib/internal/per_context/messageport.js",
+      "lib/internal/per_context/primordials.js",
+      "lib/internal/perf/event_loop_delay.js",
+      "lib/internal/perf/event_loop_utilization.js",
+      "lib/internal/perf/nodetiming.js",
+      "lib/internal/perf/observe.js",
+      "lib/internal/perf/performance.js",
+      "lib/internal/perf/performance_entry.js",
+      "lib/internal/perf/resource_timing.js",
+      "lib/internal/perf/timerify.js",
+      "lib/internal/perf/usertiming.js",
+      "lib/internal/perf/utils.js",
+      "lib/internal/priority_queue.js",
+      "lib/internal/process/execution.js",
+      "lib/internal/process/finalization.js",
+      "lib/internal/process/per_thread.js",
+      "lib/internal/process/permission.js",
+      "lib/internal/process/pre_execution.js",
+      "lib/internal/process/promises.js",
+      "lib/internal/process/report.js",
+      "lib/internal/process/signal.js",
+      "lib/internal/process/task_queues.js",
+      "lib/internal/process/warning.js",
+      "lib/internal/process/worker_thread_only.js",
+      "lib/internal/promise_hooks.js",
+      "lib/internal/querystring.js",
+      "lib/internal/quic/quic.js",
+      "lib/internal/quic/state.js",
+      "lib/internal/quic/stats.js",
+      "lib/internal/quic/symbols.js",
+      "lib/internal/readline/callbacks.js",
+      "lib/internal/readline/emitKeypressEvents.js",
+      "lib/internal/readline/interface.js",
+      "lib/internal/readline/promises.js",
+      "lib/internal/readline/utils.js",
+      "lib/internal/repl.js",
+      "lib/internal/repl/await.js",
+      "lib/internal/repl/completion.js",
+      "lib/internal/repl/history.js",
+      "lib/internal/repl/utils.js",
+      "lib/internal/socket_list.js",
+      "lib/internal/socketaddress.js",
+      "lib/internal/source_map/prepare_stack_trace.js",
+      "lib/internal/source_map/source_map.js",
+      "lib/internal/source_map/source_map_cache.js",
+      "lib/internal/source_map/source_map_cache_map.js",
+      "lib/internal/stream_base_commons.js",
+      "lib/internal/streams/add-abort-signal.js",
+      "lib/internal/streams/compose.js",
+      "lib/internal/streams/destroy.js",
+      "lib/internal/streams/duplex.js",
+      "lib/internal/streams/duplexify.js",
+      "lib/internal/streams/duplexpair.js",
+      "lib/internal/streams/end-of-stream.js",
+      "lib/internal/streams/fast-utf8-stream.js",
+      "lib/internal/streams/from.js",
+      "lib/internal/streams/lazy_transform.js",
+      "lib/internal/streams/legacy.js",
+      "lib/internal/streams/operators.js",
+      "lib/internal/streams/passthrough.js",
+      "lib/internal/streams/pipeline.js",
+      "lib/internal/streams/readable.js",
+      "lib/internal/streams/state.js",
+      "lib/internal/streams/transform.js",
+      "lib/internal/streams/utils.js",
+      "lib/internal/streams/writable.js",
+      "lib/internal/test/binding.js",
+      "lib/internal/test/transfer.js",
+      "lib/internal/test_runner/assert.js",
+      "lib/internal/test_runner/coverage.js",
+      "lib/internal/test_runner/harness.js",
+      "lib/internal/test_runner/mock/loader.js",
+      "lib/internal/test_runner/mock/mock.js",
+      "lib/internal/test_runner/mock/mock_timers.js",
+      "lib/internal/test_runner/reporter/dot.js",
+      "lib/internal/test_runner/reporter/junit.js",
+      "lib/internal/test_runner/reporter/lcov.js",
+      "lib/internal/test_runner/reporter/rerun.js",
+      "lib/internal/test_runner/reporter/spec.js",
+      "lib/internal/test_runner/reporter/tap.js",
+      "lib/internal/test_runner/reporter/utils.js",
+      "lib/internal/test_runner/reporter/v8-serializer.js",
+      "lib/internal/test_runner/runner.js",
+      "lib/internal/test_runner/snapshot.js",
+      "lib/internal/test_runner/test.js",
+      "lib/internal/test_runner/tests_stream.js",
+      "lib/internal/test_runner/utils.js",
+      "lib/internal/timers.js",
+      "lib/internal/tls/common.js",
+      "lib/internal/tls/secure-context.js",
+      "lib/internal/tls/wrap.js",
+      "lib/internal/trace_events_async_hooks.js",
+      "lib/internal/tty.js",
+      "lib/internal/url.js",
+      "lib/internal/util.js",
+      "lib/internal/util/colors.js",
+      "lib/internal/util/comparisons.js",
+      "lib/internal/util/debuglog.js",
+      "lib/internal/util/diff.js",
+      "lib/internal/util/inspect.js",
+      "lib/internal/util/inspector.js",
+      "lib/internal/util/parse_args/parse_args.js",
+      "lib/internal/util/parse_args/utils.js",
+      "lib/internal/util/trace_sigint.js",
+      "lib/internal/util/types.js",
+      "lib/internal/v8/startup_snapshot.js",
+      "lib/internal/v8_prof_polyfill.js",
+      "lib/internal/validators.js",
+      "lib/internal/vm.js",
+      "lib/internal/vm/module.js",
+      "lib/internal/wasm_web_api.js",
+      "lib/internal/watch_mode/files_watcher.js",
+      "lib/internal/watchdog.js",
+      "lib/internal/webidl.js",
+      "lib/internal/webstorage.js",
+      "lib/internal/webstreams/adapters.js",
+      "lib/internal/webstreams/compression.js",
+      "lib/internal/webstreams/encoding.js",
+      "lib/internal/webstreams/queuingstrategies.js",
+      "lib/internal/webstreams/readablestream.js",
+      "lib/internal/webstreams/transfer.js",
+      "lib/internal/webstreams/transformstream.js",
+      "lib/internal/webstreams/util.js",
+      "lib/internal/webstreams/writablestream.js",
+      "lib/internal/worker.js",
+      "lib/internal/worker/clone_dom_exception.js",
+      "lib/internal/worker/io.js",
+      "lib/internal/worker/js_transferable.js",
+      "lib/internal/worker/messaging.js",
+      "lib/module.js",
+      "lib/net.js",
+      "lib/os.js",
+      "lib/path.js",
+      "lib/path/posix.js",
+      "lib/path/win32.js",
+      "lib/perf_hooks.js",
+      "lib/process.js",
+      "lib/punycode.js",
+      "lib/querystring.js",
+      "lib/quic.js",
+      "lib/readline.js",
+      "lib/readline/promises.js",
+      "lib/repl.js",
+      "lib/sea.js",
+      "lib/sqlite.js",
+      "lib/stream.js",
+      "lib/stream/consumers.js",
+      "lib/stream/promises.js",
+      "lib/stream/web.js",
+      "lib/string_decoder.js",
+      "lib/sys.js",
+      "lib/test.js",
+      "lib/test/reporters.js",
+      "lib/timers.js",
+      "lib/timers/promises.js",
+      "lib/tls.js",
+      "lib/trace_events.js",
+      "lib/tty.js",
+      "lib/url.js",
+      "lib/util.js",
+      "lib/util/types.js",
+      "lib/v8.js",
+      "lib/vm.js",
+      "lib/wasi.js",
+      "lib/worker_threads.js",
+      "lib/zlib.js"
+    ],
+    "node_cctest_sources": [
+      "src/node_snapshot_stub.cc",
+      "test/cctest/inspector/test_network_requests_buffer.cc",
+      "test/cctest/inspector/test_node_protocol.cc",
+      "test/cctest/node_test_fixture.cc",
+      "test/cctest/test_aliased_buffer.cc",
+      "test/cctest/test_base64.cc",
+      "test/cctest/test_base_object_ptr.cc",
+      "test/cctest/test_cppgc.cc",
+      "test/cctest/test_crypto_clienthello.cc",
+      "test/cctest/test_dataqueue.cc",
+      "test/cctest/test_environment.cc",
+      "test/cctest/test_inspector_socket.cc",
+      "test/cctest/test_inspector_socket_server.cc",
+      "test/cctest/test_json_utils.cc",
+      "test/cctest/test_linked_binding.cc",
+      "test/cctest/test_lru_cache.cc",
+      "test/cctest/test_node_api.cc",
+      "test/cctest/test_node_crypto.cc",
+      "test/cctest/test_node_crypto_env.cc",
+      "test/cctest/test_node_postmortem_metadata.cc",
+      "test/cctest/test_node_task_runner.cc",
+      "test/cctest/test_path.cc",
+      "test/cctest/test_per_process.cc",
+      "test/cctest/test_platform.cc",
+      "test/cctest/test_quic_cid.cc",
+      "test/cctest/test_quic_error.cc",
+      "test/cctest/test_quic_preferredaddress.cc",
+      "test/cctest/test_quic_tokens.cc",
+      "test/cctest/test_report.cc",
+      "test/cctest/test_sockaddr.cc",
+      "test/cctest/test_string_bytes.cc",
+      "test/cctest/test_traced_value.cc",
+      "test/cctest/test_util.cc",
+      "test/cctest/node_test_fixture.h"
+    ],
+    "napi_build_version": "10",
+    "node_shared_zlib": "true",
+    "node_shared_http_parser": "true",
+    "node_shared_libuv": "true",
+    "node_shared_ada": "true",
+    "node_shared_simdjson": "true",
+    "node_shared_simdutf": "false",
+    "node_shared_brotli": "true",
+    "node_shared_cares": "true",
+    "node_shared_gtest": "false",
+    "node_shared_hdr_histogram": "true",
+    "node_shared_nbytes": "false",
+    "node_shared_nghttp2": "true",
+    "node_shared_nghttp3": "true",
+    "node_shared_ngtcp2": "true",
+    "node_use_sqlite": "true",
+    "node_shared_sqlite": "true",
+    "node_shared_temporal_capi": "false",
+    "node_shared_uvwasi": "true",
+    "node_shared_zstd": "true",
+    "v8_enable_webassembly": 1,
+    "v8_enable_javascript_promise_hooks": 1,
+    "v8_enable_lite_mode": 0,
+    "v8_enable_gdbjit": 0,
+    "v8_optimized_debug": 1,
+    "dcheck_always_on": 0,
+    "v8_enable_object_print": 1,
+    "v8_random_seed": 0,
+    "v8_promise_internal_field_count": 1,
+    "v8_use_siphash": 1,
+    "v8_enable_maglev": 1,
+    "v8_enable_pointer_compression": 0,
+    "v8_enable_sandbox": 0,
+    "v8_enable_pointer_compression_shared_cage": 0,
+    "v8_enable_external_code_space": 0,
+    "v8_enable_31bit_smis_on_64bit_arch": 0,
+    "v8_enable_extensible_ro_snapshot": 0,
+    "v8_enable_temporal_support": 0,
+    "v8_trace_maps": 0,
+    "node_use_v8_platform": "true",
+    "node_use_bundled_v8": "true",
+    "force_dynamic_crt": 1,
+    "node_enable_d8": "false",
+    "node_enable_v8windbg": "false",
+    "v8_enable_hugepage": 0,
+    "v8_enable_short_builtin_calls": 1,
+    "v8_enable_wasm_simd256_revec": 1,
+    "node_use_openssl": "true",
+    "node_shared_openssl": "true",
+    "openssl_is_fips": "false",
+    "node_fipsinstall": "false",
+    "node_without_node_options": "false",
+    "openssl_version": 811597839,
+    "node_use_quic": "false",
+    "icu_small": "false",
+    "v8_enable_i18n_support": 1,
+    "icu_ver_major": "78",
+    "icu_gyp_path": "tools/icu/icu-system.gyp",
+    "v8_enable_inspector": 1,
+    "node_section_ordering_info": "",
+    "node_builtin_shareable_builtins": [
+      "deps/cjs-module-lexer/lexer.js",
+      "deps/cjs-module-lexer/dist/lexer.js",
+      "deps/undici/undici.js",
+      "deps/amaro/dist/index.js"
+    ],
+    "ossfuzz": "false",
+    "nodedir": "/home/fahed/.cache/node-gyp/25.5.0",
+    "python": "/home/linuxbrew/.linuxbrew/opt/python@3.14/bin/python3.14",
+    "standalone_static_library": 1,
+    "global_prefix": "/home/fahed/.npm-global",
+    "node_gyp": "/home/linuxbrew/.linuxbrew/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js",
+    "user_agent": "npm/11.8.0 node/v25.5.0 linux x64 workspaces/false",
+    "include": "optional",
+    "prefix": "/home/fahed/.npm-global",
+    "npm_version": "11.8.0",
+    "init_module": "/home/fahed/.npm-init.js",
+    "globalconfig": "/home/fahed/.npm-global/etc/npmrc",
+    "local_prefix": "/home/fahed/clawd/marketing-app/server",
+    "cache": "/home/fahed/.npm",
+    "userconfig": "/home/fahed/.npmrc"
+  },
+  "target_defaults": {
+    "include_dirs": [],
+    "libraries": [],
+    "defines": [],
+    "cflags": [],
+    "conditions": [
+      [
+        "build_type==\"Release\"",
+        {
+          "variables": {
+            "v8_enable_v8_checks": 1
+          }
+        },
+        {
+          "variables": {
+            "v8_enable_v8_checks": 0
+          }
+        }
+      ]
+    ],
+    "default_configuration": "Release",
+    "configurations": {
+      "Release": {},
+      "Debug": {}
+    }
+  }
+}
diff --git a/server/node_modules/better-sqlite3/build/deps/locate_sqlite3.target.mk b/server/node_modules/better-sqlite3/build/deps/locate_sqlite3.target.mk
new file mode 100644
index 0000000..4df77da
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/deps/locate_sqlite3.target.mk
@@ -0,0 +1,42 @@
+# This file is generated by gyp; do not edit.
+
+TOOLSET := target
+TARGET := locate_sqlite3
+### Rules for action "copy_builtin_sqlite3":
+quiet_cmd_deps_sqlite3_gyp_locate_sqlite3_target_copy_builtin_sqlite3 = ACTION deps_sqlite3_gyp_locate_sqlite3_target_copy_builtin_sqlite3 $@
+cmd_deps_sqlite3_gyp_locate_sqlite3_target_copy_builtin_sqlite3 = LD_LIBRARY_PATH=$(builddir)/lib.host:$(builddir)/lib.target:$$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; cd $(srcdir)/deps; mkdir -p $(obj)/gen/sqlite3; node copy.js "$(obj)/gen/sqlite3" ""
+
+$(obj)/gen/sqlite3/sqlite3.c: obj := $(abs_obj)
+$(obj)/gen/sqlite3/sqlite3.c: builddir := $(abs_builddir)
+$(obj)/gen/sqlite3/sqlite3.c: TOOLSET := $(TOOLSET)
+$(obj)/gen/sqlite3/sqlite3.c $(obj)/gen/sqlite3/sqlite3.h $(obj)/gen/sqlite3/sqlite3ext.h: ba23eeee118cd63e16015df367567cb043fed872.intermediate
+	@:
+.INTERMEDIATE: ba23eeee118cd63e16015df367567cb043fed872.intermediate
+ba23eeee118cd63e16015df367567cb043fed872.intermediate: $(srcdir)/deps/sqlite3/sqlite3.c $(srcdir)/deps/sqlite3/sqlite3.h $(srcdir)/deps/sqlite3/sqlite3ext.h FORCE_DO_CMD
+	$(call do_cmd,touch)
+	$(call do_cmd,deps_sqlite3_gyp_locate_sqlite3_target_copy_builtin_sqlite3)
+
+all_deps += $(obj)/gen/sqlite3/sqlite3.c $(obj)/gen/sqlite3/sqlite3.h $(obj)/gen/sqlite3/sqlite3ext.h
+action_deps_sqlite3_gyp_locate_sqlite3_target_copy_builtin_sqlite3_outputs := $(obj)/gen/sqlite3/sqlite3.c $(obj)/gen/sqlite3/sqlite3.h $(obj)/gen/sqlite3/sqlite3ext.h
+
+
+### Rules for final target.
+# Build our special outputs first.
+$(obj).target/deps/locate_sqlite3.stamp: | $(action_deps_sqlite3_gyp_locate_sqlite3_target_copy_builtin_sqlite3_outputs)
+
+# Preserve order dependency of special output on deps.
+$(action_deps_sqlite3_gyp_locate_sqlite3_target_copy_builtin_sqlite3_outputs): | 
+
+$(obj).target/deps/locate_sqlite3.stamp: TOOLSET := $(TOOLSET)
+$(obj).target/deps/locate_sqlite3.stamp:  FORCE_DO_CMD
+	$(call do_cmd,touch)
+
+all_deps += $(obj).target/deps/locate_sqlite3.stamp
+# Add target alias
+.PHONY: locate_sqlite3
+locate_sqlite3: $(obj).target/deps/locate_sqlite3.stamp
+
+# Add target alias to "all" target.
+.PHONY: all
+all: locate_sqlite3
+
diff --git a/server/node_modules/better-sqlite3/build/deps/sqlite3.Makefile b/server/node_modules/better-sqlite3/build/deps/sqlite3.Makefile
new file mode 100644
index 0000000..8fe2ceb
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/deps/sqlite3.Makefile
@@ -0,0 +1,6 @@
+# This file is generated by gyp; do not edit.
+
+export builddir_name ?= ./build/deps/.
+.PHONY: all
+all:
+	$(MAKE) -C .. locate_sqlite3 sqlite3
diff --git a/server/node_modules/better-sqlite3/build/deps/sqlite3.target.mk b/server/node_modules/better-sqlite3/build/deps/sqlite3.target.mk
new file mode 100644
index 0000000..3eb82c3
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/deps/sqlite3.target.mk
@@ -0,0 +1,247 @@
+# This file is generated by gyp; do not edit.
+
+TOOLSET := target
+TARGET := sqlite3
+DEFS_Debug := \
+	'-DNODE_GYP_MODULE_NAME=sqlite3' \
+	'-DUSING_UV_SHARED=1' \
+	'-DUSING_V8_SHARED=1' \
+	'-DV8_DEPRECATION_WARNINGS=1' \
+	'-D_GLIBCXX_USE_CXX11_ABI=1' \
+	'-D_FILE_OFFSET_BITS=64' \
+	'-D_LARGEFILE_SOURCE' \
+	'-D__STDC_FORMAT_MACROS' \
+	'-DHAVE_INT16_T=1' \
+	'-DHAVE_INT32_T=1' \
+	'-DHAVE_INT8_T=1' \
+	'-DHAVE_STDINT_H=1' \
+	'-DHAVE_UINT16_T=1' \
+	'-DHAVE_UINT32_T=1' \
+	'-DHAVE_UINT8_T=1' \
+	'-DHAVE_USLEEP=1' \
+	'-DSQLITE_DEFAULT_CACHE_SIZE=-16000' \
+	'-DSQLITE_DEFAULT_FOREIGN_KEYS=1' \
+	'-DSQLITE_DEFAULT_MEMSTATUS=0' \
+	'-DSQLITE_DEFAULT_WAL_SYNCHRONOUS=1' \
+	'-DSQLITE_DQS=0' \
+	'-DSQLITE_ENABLE_COLUMN_METADATA' \
+	'-DSQLITE_ENABLE_DBSTAT_VTAB' \
+	'-DSQLITE_ENABLE_DESERIALIZE' \
+	'-DSQLITE_ENABLE_FTS3' \
+	'-DSQLITE_ENABLE_FTS3_PARENTHESIS' \
+	'-DSQLITE_ENABLE_FTS4' \
+	'-DSQLITE_ENABLE_FTS5' \
+	'-DSQLITE_ENABLE_GEOPOLY' \
+	'-DSQLITE_ENABLE_JSON1' \
+	'-DSQLITE_ENABLE_MATH_FUNCTIONS' \
+	'-DSQLITE_ENABLE_RTREE' \
+	'-DSQLITE_ENABLE_STAT4' \
+	'-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT' \
+	'-DSQLITE_LIKE_DOESNT_MATCH_BLOBS' \
+	'-DSQLITE_OMIT_DEPRECATED' \
+	'-DSQLITE_OMIT_PROGRESS_CALLBACK' \
+	'-DSQLITE_OMIT_SHARED_CACHE' \
+	'-DSQLITE_OMIT_TCL_VARIABLE' \
+	'-DSQLITE_SOUNDEX' \
+	'-DSQLITE_THREADSAFE=2' \
+	'-DSQLITE_TRACE_SIZE_LIMIT=32' \
+	'-DSQLITE_USE_URI=0' \
+	'-DDEBUG' \
+	'-D_DEBUG' \
+	'-DSQLITE_DEBUG' \
+	'-DSQLITE_MEMDEBUG' \
+	'-DSQLITE_ENABLE_API_ARMOR' \
+	'-DSQLITE_WIN32_MALLOC_VALIDATE'
+
+# Flags passed to all source files.
+CFLAGS_Debug := \
+	-fPIC \
+	-pthread \
+	-Wall \
+	-Wextra \
+	-Wno-unused-parameter \
+	-fPIC \
+	-std=c99 \
+	-w \
+	-m64 \
+	-g \
+	-O0 \
+	-O0
+
+# Flags passed to only C files.
+CFLAGS_C_Debug :=
+
+# Flags passed to only C++ files.
+CFLAGS_CC_Debug := \
+	-fno-rtti \
+	-fno-exceptions \
+	-fno-strict-aliasing \
+	-std=gnu++20
+
+INCS_Debug := \
+	-I/home/fahed/.cache/node-gyp/25.5.0/include/node \
+	-I/home/fahed/.cache/node-gyp/25.5.0/src \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/config \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/openssl/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/uv/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/zlib \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/v8/include \
+	-I$(obj)/gen/sqlite3
+
+DEFS_Release := \
+	'-DNODE_GYP_MODULE_NAME=sqlite3' \
+	'-DUSING_UV_SHARED=1' \
+	'-DUSING_V8_SHARED=1' \
+	'-DV8_DEPRECATION_WARNINGS=1' \
+	'-D_GLIBCXX_USE_CXX11_ABI=1' \
+	'-D_FILE_OFFSET_BITS=64' \
+	'-D_LARGEFILE_SOURCE' \
+	'-D__STDC_FORMAT_MACROS' \
+	'-DHAVE_INT16_T=1' \
+	'-DHAVE_INT32_T=1' \
+	'-DHAVE_INT8_T=1' \
+	'-DHAVE_STDINT_H=1' \
+	'-DHAVE_UINT16_T=1' \
+	'-DHAVE_UINT32_T=1' \
+	'-DHAVE_UINT8_T=1' \
+	'-DHAVE_USLEEP=1' \
+	'-DSQLITE_DEFAULT_CACHE_SIZE=-16000' \
+	'-DSQLITE_DEFAULT_FOREIGN_KEYS=1' \
+	'-DSQLITE_DEFAULT_MEMSTATUS=0' \
+	'-DSQLITE_DEFAULT_WAL_SYNCHRONOUS=1' \
+	'-DSQLITE_DQS=0' \
+	'-DSQLITE_ENABLE_COLUMN_METADATA' \
+	'-DSQLITE_ENABLE_DBSTAT_VTAB' \
+	'-DSQLITE_ENABLE_DESERIALIZE' \
+	'-DSQLITE_ENABLE_FTS3' \
+	'-DSQLITE_ENABLE_FTS3_PARENTHESIS' \
+	'-DSQLITE_ENABLE_FTS4' \
+	'-DSQLITE_ENABLE_FTS5' \
+	'-DSQLITE_ENABLE_GEOPOLY' \
+	'-DSQLITE_ENABLE_JSON1' \
+	'-DSQLITE_ENABLE_MATH_FUNCTIONS' \
+	'-DSQLITE_ENABLE_RTREE' \
+	'-DSQLITE_ENABLE_STAT4' \
+	'-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT' \
+	'-DSQLITE_LIKE_DOESNT_MATCH_BLOBS' \
+	'-DSQLITE_OMIT_DEPRECATED' \
+	'-DSQLITE_OMIT_PROGRESS_CALLBACK' \
+	'-DSQLITE_OMIT_SHARED_CACHE' \
+	'-DSQLITE_OMIT_TCL_VARIABLE' \
+	'-DSQLITE_SOUNDEX' \
+	'-DSQLITE_THREADSAFE=2' \
+	'-DSQLITE_TRACE_SIZE_LIMIT=32' \
+	'-DSQLITE_USE_URI=0' \
+	'-DNDEBUG'
+
+# Flags passed to all source files.
+CFLAGS_Release := \
+	-fPIC \
+	-pthread \
+	-Wall \
+	-Wextra \
+	-Wno-unused-parameter \
+	-fPIC \
+	-std=c99 \
+	-w \
+	-m64 \
+	-O3 \
+	-O3 \
+	-fno-omit-frame-pointer
+
+# Flags passed to only C files.
+CFLAGS_C_Release :=
+
+# Flags passed to only C++ files.
+CFLAGS_CC_Release := \
+	-fno-rtti \
+	-fno-exceptions \
+	-fno-strict-aliasing \
+	-std=gnu++20
+
+INCS_Release := \
+	-I/home/fahed/.cache/node-gyp/25.5.0/include/node \
+	-I/home/fahed/.cache/node-gyp/25.5.0/src \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/config \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/openssl/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/uv/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/zlib \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/v8/include \
+	-I$(obj)/gen/sqlite3
+
+OBJS := \
+	$(obj).target/$(TARGET)/gen/sqlite3/sqlite3.o
+
+# Add to the list of files we specially track dependencies for.
+all_deps += $(OBJS)
+
+# Make sure our dependencies are built before any of us.
+$(OBJS): | $(obj).target/deps/locate_sqlite3.stamp
+
+# CFLAGS et al overrides must be target-local.
+# See "Target-specific Variable Values" in the GNU Make manual.
+$(OBJS): TOOLSET := $(TOOLSET)
+$(OBJS): GYP_CFLAGS := $(DEFS_$(BUILDTYPE)) $(INCS_$(BUILDTYPE))  $(CFLAGS_$(BUILDTYPE)) $(CFLAGS_C_$(BUILDTYPE))
+$(OBJS): GYP_CXXFLAGS := $(DEFS_$(BUILDTYPE)) $(INCS_$(BUILDTYPE))  $(CFLAGS_$(BUILDTYPE)) $(CFLAGS_CC_$(BUILDTYPE))
+
+# Suffix rules, putting all outputs into $(obj).
+
+$(obj).$(TOOLSET)/$(TARGET)/%.o: $(srcdir)/%.c FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+
+# Try building from generated source, too.
+
+$(obj).$(TOOLSET)/$(TARGET)/%.o: $(obj).$(TOOLSET)/%.c FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+
+$(obj).$(TOOLSET)/$(TARGET)/%.o: $(obj)/%.c FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+
+# End of this set of suffix rules
+### Rules for final target.
+LDFLAGS_Debug := \
+	-pthread \
+	-rdynamic \
+	-fPIC \
+	-m64
+
+LDFLAGS_Release := \
+	-pthread \
+	-rdynamic \
+	-fPIC \
+	-m64
+
+LIBS :=
+
+$(obj).target/deps/sqlite3.a: GYP_LDFLAGS := $(LDFLAGS_$(BUILDTYPE))
+$(obj).target/deps/sqlite3.a: LIBS := $(LIBS)
+$(obj).target/deps/sqlite3.a: TOOLSET := $(TOOLSET)
+$(obj).target/deps/sqlite3.a: $(OBJS)
+	$(call create_archive,$@,$^)
+
+# Add target alias
+.PHONY: sqlite3
+sqlite3: $(obj).target/deps/sqlite3.a
+
+# Add target alias to "all" target.
+.PHONY: all
+all: sqlite3
+
+# Add target alias
+.PHONY: sqlite3
+sqlite3: $(builddir)/sqlite3.a
+
+# Copy this to the static library output path.
+$(builddir)/sqlite3.a: TOOLSET := $(TOOLSET)
+$(builddir)/sqlite3.a: $(obj).target/deps/sqlite3.a FORCE_DO_CMD
+	$(call do_cmd,copy)
+
+all_deps += $(builddir)/sqlite3.a
+# Short alias for building this static library.
+.PHONY: sqlite3.a
+sqlite3.a: $(obj).target/deps/sqlite3.a $(builddir)/sqlite3.a
+
+# Add static library to "all" target.
+.PHONY: all
+all: $(builddir)/sqlite3.a
+
diff --git a/server/node_modules/better-sqlite3/build/test_extension.target.mk b/server/node_modules/better-sqlite3/build/test_extension.target.mk
new file mode 100644
index 0000000..3c03f72
--- /dev/null
+++ b/server/node_modules/better-sqlite3/build/test_extension.target.mk
@@ -0,0 +1,168 @@
+# This file is generated by gyp; do not edit.
+
+TOOLSET := target
+TARGET := test_extension
+DEFS_Debug := \
+	'-DNODE_GYP_MODULE_NAME=test_extension' \
+	'-DUSING_UV_SHARED=1' \
+	'-DUSING_V8_SHARED=1' \
+	'-DV8_DEPRECATION_WARNINGS=1' \
+	'-D_GLIBCXX_USE_CXX11_ABI=1' \
+	'-D_FILE_OFFSET_BITS=64' \
+	'-D_LARGEFILE_SOURCE' \
+	'-D__STDC_FORMAT_MACROS' \
+	'-DBUILDING_NODE_EXTENSION' \
+	'-DDEBUG' \
+	'-D_DEBUG' \
+	'-DSQLITE_DEBUG' \
+	'-DSQLITE_MEMDEBUG' \
+	'-DSQLITE_ENABLE_API_ARMOR' \
+	'-DSQLITE_WIN32_MALLOC_VALIDATE'
+
+# Flags passed to all source files.
+CFLAGS_Debug := \
+	-fPIC \
+	-pthread \
+	-Wall \
+	-Wextra \
+	-Wno-unused-parameter \
+	-fPIC \
+	-m64 \
+	-g \
+	-O0 \
+	-O0
+
+# Flags passed to only C files.
+CFLAGS_C_Debug :=
+
+# Flags passed to only C++ files.
+CFLAGS_CC_Debug := \
+	-fno-rtti \
+	-fno-exceptions \
+	-fno-strict-aliasing \
+	-std=gnu++20
+
+INCS_Debug := \
+	-I/home/fahed/.cache/node-gyp/25.5.0/include/node \
+	-I/home/fahed/.cache/node-gyp/25.5.0/src \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/config \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/openssl/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/uv/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/zlib \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/v8/include \
+	-I$(obj)/gen/sqlite3
+
+DEFS_Release := \
+	'-DNODE_GYP_MODULE_NAME=test_extension' \
+	'-DUSING_UV_SHARED=1' \
+	'-DUSING_V8_SHARED=1' \
+	'-DV8_DEPRECATION_WARNINGS=1' \
+	'-D_GLIBCXX_USE_CXX11_ABI=1' \
+	'-D_FILE_OFFSET_BITS=64' \
+	'-D_LARGEFILE_SOURCE' \
+	'-D__STDC_FORMAT_MACROS' \
+	'-DBUILDING_NODE_EXTENSION' \
+	'-DNDEBUG'
+
+# Flags passed to all source files.
+CFLAGS_Release := \
+	-fPIC \
+	-pthread \
+	-Wall \
+	-Wextra \
+	-Wno-unused-parameter \
+	-fPIC \
+	-m64 \
+	-O3 \
+	-O3 \
+	-fno-omit-frame-pointer
+
+# Flags passed to only C files.
+CFLAGS_C_Release :=
+
+# Flags passed to only C++ files.
+CFLAGS_CC_Release := \
+	-fno-rtti \
+	-fno-exceptions \
+	-fno-strict-aliasing \
+	-std=gnu++20
+
+INCS_Release := \
+	-I/home/fahed/.cache/node-gyp/25.5.0/include/node \
+	-I/home/fahed/.cache/node-gyp/25.5.0/src \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/config \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/openssl/openssl/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/uv/include \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/zlib \
+	-I/home/fahed/.cache/node-gyp/25.5.0/deps/v8/include \
+	-I$(obj)/gen/sqlite3
+
+OBJS := \
+	$(obj).target/$(TARGET)/deps/test_extension.o
+
+# Add to the list of files we specially track dependencies for.
+all_deps += $(OBJS)
+
+# Make sure our dependencies are built before any of us.
+$(OBJS): | $(builddir)/sqlite3.a $(obj).target/deps/locate_sqlite3.stamp $(obj).target/deps/sqlite3.a
+
+# CFLAGS et al overrides must be target-local.
+# See "Target-specific Variable Values" in the GNU Make manual.
+$(OBJS): TOOLSET := $(TOOLSET)
+$(OBJS): GYP_CFLAGS := $(DEFS_$(BUILDTYPE)) $(INCS_$(BUILDTYPE))  $(CFLAGS_$(BUILDTYPE)) $(CFLAGS_C_$(BUILDTYPE))
+$(OBJS): GYP_CXXFLAGS := $(DEFS_$(BUILDTYPE)) $(INCS_$(BUILDTYPE))  $(CFLAGS_$(BUILDTYPE)) $(CFLAGS_CC_$(BUILDTYPE))
+
+# Suffix rules, putting all outputs into $(obj).
+
+$(obj).$(TOOLSET)/$(TARGET)/%.o: $(srcdir)/%.c FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+
+# Try building from generated source, too.
+
+$(obj).$(TOOLSET)/$(TARGET)/%.o: $(obj).$(TOOLSET)/%.c FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+
+$(obj).$(TOOLSET)/$(TARGET)/%.o: $(obj)/%.c FORCE_DO_CMD
+	@$(call do_cmd,cc,1)
+
+# End of this set of suffix rules
+### Rules for final target.
+LDFLAGS_Debug := \
+	-pthread \
+	-rdynamic \
+	-fPIC \
+	-m64
+
+LDFLAGS_Release := \
+	-pthread \
+	-rdynamic \
+	-fPIC \
+	-m64
+
+LIBS :=
+
+$(obj).target/test_extension.node: GYP_LDFLAGS := $(LDFLAGS_$(BUILDTYPE))
+$(obj).target/test_extension.node: LIBS := $(LIBS)
+$(obj).target/test_extension.node: TOOLSET := $(TOOLSET)
+$(obj).target/test_extension.node: $(OBJS) $(obj).target/deps/sqlite3.a FORCE_DO_CMD
+	$(call do_cmd,solink_module)
+
+all_deps += $(obj).target/test_extension.node
+# Add target alias
+.PHONY: test_extension
+test_extension: $(builddir)/test_extension.node
+
+# Copy this to the executable output path.
+$(builddir)/test_extension.node: TOOLSET := $(TOOLSET)
+$(builddir)/test_extension.node: $(obj).target/test_extension.node FORCE_DO_CMD
+	$(call do_cmd,copy)
+
+all_deps += $(builddir)/test_extension.node
+# Short alias for building this executable.
+.PHONY: test_extension.node
+test_extension.node: $(obj).target/test_extension.node $(builddir)/test_extension.node
+
+# Add executable to "all" target.
+.PHONY: all
+all: $(builddir)/test_extension.node
+
diff --git a/server/node_modules/better-sqlite3/deps/common.gypi b/server/node_modules/better-sqlite3/deps/common.gypi
new file mode 100644
index 0000000..613adc3
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/common.gypi
@@ -0,0 +1,68 @@
+# ===
+# This configuration defines the differences between Release and Debug builds.
+# Some miscellaneous Windows settings are also defined here.
+# ===
+
+{
+  'variables': { 'sqlite3%': '' },
+  'target_defaults': {
+    'default_configuration': 'Release',
+    'msvs_settings': {
+      'VCCLCompilerTool': {
+        'ExceptionHandling': 1,
+      },
+    },
+    'conditions': [
+      ['OS == "win"', {
+        'defines': ['WIN32'],
+      }],
+    ],
+    'configurations': {
+      'Debug': {
+        'defines!': [
+          'NDEBUG',
+        ],
+        'defines': [
+          'DEBUG',
+          '_DEBUG',
+          'SQLITE_DEBUG',
+          'SQLITE_MEMDEBUG',
+          'SQLITE_ENABLE_API_ARMOR',
+          'SQLITE_WIN32_MALLOC_VALIDATE',
+        ],
+        'cflags': [
+          '-O0',
+        ],
+        'xcode_settings': {
+          'MACOSX_DEPLOYMENT_TARGET': '10.7',
+          'GCC_OPTIMIZATION_LEVEL': '0',
+          'GCC_GENERATE_DEBUGGING_SYMBOLS': 'YES',
+        },
+        'msvs_settings': {
+          'VCLinkerTool': {
+            'GenerateDebugInformation': 'true',
+          },
+        },
+      },
+      'Release': {
+        'defines!': [
+          'DEBUG',
+          '_DEBUG',
+        ],
+        'defines': [
+          'NDEBUG',
+        ],
+        'cflags': [
+          '-O3',
+        ],
+        'xcode_settings': {
+          'MACOSX_DEPLOYMENT_TARGET': '10.7',
+          'GCC_OPTIMIZATION_LEVEL': '3',
+          'GCC_GENERATE_DEBUGGING_SYMBOLS': 'NO',
+          'DEAD_CODE_STRIPPING': 'YES',
+          'GCC_INLINES_ARE_PRIVATE_EXTERN': 'YES',
+        },
+      },
+    },
+  },
+}
diff --git a/server/node_modules/better-sqlite3/deps/copy.js b/server/node_modules/better-sqlite3/deps/copy.js
new file mode 100644
index 0000000..3d2dd56
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/copy.js
@@ -0,0 +1,31 @@
+'use strict';
+const path = require('path');
+const fs = require('fs');
+
+const dest = process.argv[2];
+const source = path.resolve(path.sep, process.argv[3] || path.join(__dirname, 'sqlite3'));
+const files = [
+	{ filename: 'sqlite3.c', optional: false },
+	{ filename: 'sqlite3.h', optional: false },
+];
+
+if (process.argv[3]) {
+	// Support "_HAVE_SQLITE_CONFIG_H" in custom builds.
+	files.push({ filename: 'config.h', optional: true });
+} else {
+	// Required for some tests.
+	files.push({ filename: 'sqlite3ext.h', optional: false });
+}
+
+for (const { filename, optional } of files) {
+	const sourceFilepath = path.join(source, filename);
+	const destFilepath = path.join(dest, filename);
+
+	if (optional && !fs.existsSync(sourceFilepath)) {
+		continue;
+	}
+
+	fs.accessSync(sourceFilepath);
+	fs.mkdirSync(path.dirname(destFilepath), { recursive: true });
+	fs.copyFileSync(sourceFilepath, destFilepath);
+}
diff --git a/server/node_modules/better-sqlite3/deps/defines.gypi b/server/node_modules/better-sqlite3/deps/defines.gypi
new file mode 100644
index 0000000..51aaafe
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/defines.gypi
@@ -0,0 +1,41 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY deps/download.sh (DO NOT EDIT)
+
+{
+  'defines': [
+    'HAVE_INT16_T=1',
+    'HAVE_INT32_T=1',
+    'HAVE_INT8_T=1',
+    'HAVE_STDINT_H=1',
+    'HAVE_UINT16_T=1',
+    'HAVE_UINT32_T=1',
+    'HAVE_UINT8_T=1',
+    'HAVE_USLEEP=1',
+    'SQLITE_DEFAULT_CACHE_SIZE=-16000',
+    'SQLITE_DEFAULT_FOREIGN_KEYS=1',
+    'SQLITE_DEFAULT_MEMSTATUS=0',
+    'SQLITE_DEFAULT_WAL_SYNCHRONOUS=1',
+    'SQLITE_DQS=0',
+    'SQLITE_ENABLE_COLUMN_METADATA',
+    'SQLITE_ENABLE_DBSTAT_VTAB',
+    'SQLITE_ENABLE_DESERIALIZE',
+    'SQLITE_ENABLE_FTS3',
+    'SQLITE_ENABLE_FTS3_PARENTHESIS',
+    'SQLITE_ENABLE_FTS4',
+    'SQLITE_ENABLE_FTS5',
+    'SQLITE_ENABLE_GEOPOLY',
+    'SQLITE_ENABLE_JSON1',
+    'SQLITE_ENABLE_MATH_FUNCTIONS',
+    'SQLITE_ENABLE_RTREE',
+    'SQLITE_ENABLE_STAT4',
+    'SQLITE_ENABLE_UPDATE_DELETE_LIMIT',
+    'SQLITE_LIKE_DOESNT_MATCH_BLOBS',
+    'SQLITE_OMIT_DEPRECATED',
+    'SQLITE_OMIT_PROGRESS_CALLBACK',
+    'SQLITE_OMIT_SHARED_CACHE',
+    'SQLITE_OMIT_TCL_VARIABLE',
+    'SQLITE_SOUNDEX',
+    'SQLITE_THREADSAFE=2',
+    'SQLITE_TRACE_SIZE_LIMIT=32',
+    'SQLITE_USE_URI=0',
+  ],
+}
diff --git a/server/node_modules/better-sqlite3/deps/download.sh b/server/node_modules/better-sqlite3/deps/download.sh
new file mode 100755
index 0000000..1304086
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/download.sh
@@ -0,0 +1,122 @@
+#!/usr/bin/env bash
+
+# ===
+# This script defines and generates the bundled SQLite unit (sqlite3.c).
+#
+# The following steps are taken:
+# 1. populate the shell environment with the defined compile-time options.
+# 2. download and extract the SQLite source code into a temporary directory.
+# 3. run "sh configure" and "make sqlite3.c" within the source directory.
+# 4. copy the generated amalgamation into the output directory (./sqlite3).
+# 5. export the defined compile-time options to a gyp file (./defines.gypi).
+# 6. update the docs (../docs/compilation.md) with details of this distribution.
+#
+# When a user builds better-sqlite3, the following steps are taken:
+# 1. node-gyp loads the previously exported compile-time options (defines.gypi).
+# 2. the copy.js script copies the bundled amalgamation into the build folder.
+# 3. node-gyp compiles the copied sqlite3.c along with better_sqlite3.cpp.
+# 4. node-gyp links the two resulting binaries to generate better_sqlite3.node.
+# ===
+
+YEAR="2025"
+VERSION="3490200"
+
+# Defines below are sorted alphabetically
+DEFINES="
+HAVE_INT16_T=1
+HAVE_INT32_T=1
+HAVE_INT8_T=1
+HAVE_STDINT_H=1
+HAVE_UINT16_T=1
+HAVE_UINT32_T=1
+HAVE_UINT8_T=1
+HAVE_USLEEP=1
+SQLITE_DEFAULT_CACHE_SIZE=-16000
+SQLITE_DEFAULT_FOREIGN_KEYS=1
+SQLITE_DEFAULT_MEMSTATUS=0
+SQLITE_DEFAULT_WAL_SYNCHRONOUS=1
+SQLITE_DQS=0
+SQLITE_ENABLE_COLUMN_METADATA
+SQLITE_ENABLE_DBSTAT_VTAB
+SQLITE_ENABLE_DESERIALIZE
+SQLITE_ENABLE_FTS3
+SQLITE_ENABLE_FTS3_PARENTHESIS
+SQLITE_ENABLE_FTS4
+SQLITE_ENABLE_FTS5
+SQLITE_ENABLE_GEOPOLY
+SQLITE_ENABLE_JSON1
+SQLITE_ENABLE_MATH_FUNCTIONS
+SQLITE_ENABLE_RTREE
+SQLITE_ENABLE_STAT4
+SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+SQLITE_LIKE_DOESNT_MATCH_BLOBS
+SQLITE_OMIT_DEPRECATED
+SQLITE_OMIT_PROGRESS_CALLBACK
+SQLITE_OMIT_SHARED_CACHE
+SQLITE_OMIT_TCL_VARIABLE
+SQLITE_SOUNDEX
+SQLITE_THREADSAFE=2
+SQLITE_TRACE_SIZE_LIMIT=32
+SQLITE_USE_URI=0
+"
+
+# ========== START SCRIPT ========== #
+
+echo "setting up environment..."
+DEPS="$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)"
+TEMP="$DEPS/temp"
+OUTPUT="$DEPS/sqlite3"
+rm -rf "$TEMP"
+rm -rf "$OUTPUT"
+mkdir -p "$TEMP"
+mkdir -p "$OUTPUT"
+export CFLAGS=`echo $(echo "$DEFINES" | sed -e "/^\s*$/d" -e "s/^/-D/")`
+
+echo "downloading source..."
+curl -#f "https://www.sqlite.org/$YEAR/sqlite-src-$VERSION.zip" > "$TEMP/source.zip" || exit 1
+
+echo "extracting source..."
+unzip "$TEMP/source.zip" -d "$TEMP" > /dev/null || exit 1
+cd "$TEMP/sqlite-src-$VERSION" || exit 1
+
+echo "configuring amalgamation..."
+sh configure > /dev/null || exit 1
+
+echo "building amalgamation..."
+make OPTIONS="$CFLAGS" sqlite3.c > /dev/null || exit 1
+
+echo "copying amalgamation..."
+cp sqlite3.c sqlite3.h sqlite3ext.h "$OUTPUT/" || exit 1
+
+echo "applying patches..."
+cd "$DEPS" || exit 1
+for patch in patches/*.patch; do
+  # If a patch fails, just skip it an move on.
+  # By default `patch` tries to be clever and reverse the patch, so we have to specify `--forward`.
+  # If the patch fails, we # don't write .orig and .rej files, so we have to specify `--no-backup-if-mismatch` and `--reject-file=-`.
+  patch --batch --forward --no-backup-if-mismatch --reject-file=- -p2 < "$patch"
+done
+
+echo "updating gyp configs..."
+GYP="$DEPS/defines.gypi"
+printf "# THIS FILE IS AUTOMATICALLY GENERATED BY deps/download.sh (DO NOT EDIT)\n\n{\n  'defines': [\n" > "$GYP"
+printf "$DEFINES" | sed -e "/^\s*$/d" -e "s/$.*$/    '\1',/" >> "$GYP"
+printf "  ],\n}\n" >> "$GYP"
+
+echo "updating docs..."
+DOCS="$DEPS/../docs/compilation.md"
+MAJOR=`expr "${VERSION:0:1}" + 0`
+MINOR=`expr "${VERSION:1:2}" + 0`
+PATCH=`expr "${VERSION:3:2}" + 0`
+sed -Ei.bak -e "s/version [0-9]+\.[0-9]+\.[0-9]+/version $MAJOR.$MINOR.$PATCH/g" "$DOCS"
+sed -i.bak -e "/^SQLITE_/,\$d" "$DOCS"
+sed -i.bak -e "/^HAVE_/,\$d" "$DOCS"
+rm "$DOCS".bak
+printf "$DEFINES" | sed -e "/^\s*$/d" >> "$DOCS"
+printf "\`\`\`\n" >> "$DOCS"
+
+echo "cleaning up..."
+cd - > /dev/null || exit 1
+rm -rf "$TEMP"
+
+echo "done!"
diff --git a/server/node_modules/better-sqlite3/deps/patches/1208.patch b/server/node_modules/better-sqlite3/deps/patches/1208.patch
new file mode 100644
index 0000000..08d88ca
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/patches/1208.patch
@@ -0,0 +1,15 @@
+diff --git a/deps/sqlite3/sqlite3.c b/deps/sqlite3/sqlite3.c
+index b1a807f..38bd1e6 100644
+--- a/deps/sqlite3/sqlite3.c
++++ b/deps/sqlite3/sqlite3.c
+@@ -24887,8 +24887,8 @@ static const struct {
+   /* 1 */ { 6, "minute",   7.7379e+12,        60.0  },
+   /* 2 */ { 4, "hour",     1.2897e+11,      3600.0  },
+   /* 3 */ { 3, "day",      5373485.0,      86400.0  },
+-  /* 4 */ { 5, "month",    176546.0,  30.0*86400.0  },
+-  /* 5 */ { 4, "year",     14713.0,  365.0*86400.0  },
++  /* 4 */ { 5, "month",    176546.0,     2592000.0  },
++  /* 5 */ { 4, "year",     14713.0,     31536000.0  },
+ };
+ 
+ /*
diff --git a/server/node_modules/better-sqlite3/deps/sqlite3.gyp b/server/node_modules/better-sqlite3/deps/sqlite3.gyp
new file mode 100755
index 0000000..7259dfe
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/sqlite3.gyp
@@ -0,0 +1,80 @@
+# ===
+# This configuration defines options specific to compiling SQLite itself.
+# Compile-time options are loaded by the auto-generated file "defines.gypi".
+# The --sqlite3 option can be provided to use a custom amalgamation instead.
+# ===
+
+{
+  'includes': ['common.gypi'],
+  'targets': [
+    {
+      'target_name': 'locate_sqlite3',
+      'type': 'none',
+      'hard_dependency': 1,
+      'conditions': [
+        ['sqlite3 == ""', {
+          'actions': [{
+            'action_name': 'copy_builtin_sqlite3',
+            'inputs': [
+              'sqlite3/sqlite3.c',
+              'sqlite3/sqlite3.h',
+              'sqlite3/sqlite3ext.h',
+            ],
+            'outputs': [
+              '<(SHARED_INTERMEDIATE_DIR)/sqlite3/sqlite3.c',
+              '<(SHARED_INTERMEDIATE_DIR)/sqlite3/sqlite3.h',
+              '<(SHARED_INTERMEDIATE_DIR)/sqlite3/sqlite3ext.h',
+            ],
+            'action': ['node', 'copy.js', '<(SHARED_INTERMEDIATE_DIR)/sqlite3', ''],
+          }],
+        }, {
+          'actions': [{
+            'action_name': 'copy_custom_sqlite3',
+            'inputs': [
+              '<(sqlite3)/sqlite3.c',
+              '<(sqlite3)/sqlite3.h',
+            ],
+            'outputs': [
+              '<(SHARED_INTERMEDIATE_DIR)/sqlite3/sqlite3.c',
+              '<(SHARED_INTERMEDIATE_DIR)/sqlite3/sqlite3.h',
+            ],
+            'action': ['node', 'copy.js', '<(SHARED_INTERMEDIATE_DIR)/sqlite3', '<(sqlite3)'],
+          }],
+        }],
+      ],
+    },
+    {
+      'target_name': 'sqlite3',
+      'type': 'static_library',
+      'dependencies': ['locate_sqlite3'],
+      'sources': ['<(SHARED_INTERMEDIATE_DIR)/sqlite3/sqlite3.c'],
+      'include_dirs': ['<(SHARED_INTERMEDIATE_DIR)/sqlite3/'],
+      'direct_dependent_settings': {
+        'include_dirs': ['<(SHARED_INTERMEDIATE_DIR)/sqlite3/'],
+      },
+      'cflags': ['-std=c99', '-w'],
+      'xcode_settings': {
+        'OTHER_CFLAGS': ['-std=c99'],
+        'WARNING_CFLAGS': ['-w'],
+      },
+      'conditions': [
+        ['sqlite3 == ""', {
+          'includes': ['defines.gypi'],
+        }, {
+          'defines': [
+            # This is currently required by better-sqlite3.
+            'SQLITE_ENABLE_COLUMN_METADATA',
+          ],
+        }]
+      ],
+      'configurations': {
+        'Debug': {
+          'msvs_settings': { 'VCCLCompilerTool': { 'RuntimeLibrary': 1 } }, # static debug
+        },
+        'Release': {
+          'msvs_settings': { 'VCCLCompilerTool': { 'RuntimeLibrary': 0 } }, # static release
+        },
+      },
+    },
+  ],
+}
diff --git a/server/node_modules/better-sqlite3/deps/sqlite3/sqlite3.c b/server/node_modules/better-sqlite3/deps/sqlite3/sqlite3.c
new file mode 100644
index 0000000..d71fff3
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/sqlite3/sqlite3.c
@@ -0,0 +1,261480 @@
+/******************************************************************************
+** This file is an amalgamation of many separate C source files from SQLite
+** version 3.49.2.  By combining all the individual C code files into this
+** single large file, the entire code can be compiled as a single translation
+** unit.  This allows many compilers to do optimizations that would not be
+** possible if the files were compiled separately.  Performance improvements
+** of 5% or more are commonly seen when SQLite is compiled as a single
+** translation unit.
+**
+** This file is all you need to compile SQLite.  To use SQLite in other
+** programs, you need this file and the "sqlite3.h" header file that defines
+** the programming interface to the SQLite library.  (If you do not have
+** the "sqlite3.h" header file at hand, you will find a copy embedded within
+** the text of this file.  Search for "Begin file sqlite3.h" to find the start
+** of the embedded sqlite3.h header file.) Additional code files may be needed
+** if you want a wrapper to interface SQLite with your choice of programming
+** language. The code for the "sqlite3" command-line shell is also in a
+** separate file. This file contains only code for the core SQLite library.
+**
+** The content in this amalgamation comes from Fossil check-in
+** 17144570b0d96ae63cd6f3edca39e27ebd74 with changes in files:
+**
+**    
+*/
+#ifndef SQLITE_AMALGAMATION
+#define SQLITE_CORE 1
+#define SQLITE_AMALGAMATION 1
+#ifndef SQLITE_PRIVATE
+# define SQLITE_PRIVATE static
+#endif
+#define SQLITE_UDL_CAPABLE_PARSER 1
+/************** Begin file sqliteInt.h ***************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Internal interface definitions for SQLite.
+**
+*/
+#ifndef SQLITEINT_H
+#define SQLITEINT_H
+
+/* Special Comments:
+**
+** Some comments have special meaning to the tools that measure test
+** coverage:
+**
+**    NO_TEST                     - The branches on this line are not
+**                                  measured by branch coverage.  This is
+**                                  used on lines of code that actually
+**                                  implement parts of coverage testing.
+**
+**    OPTIMIZATION-IF-TRUE        - This branch is allowed to always be false
+**                                  and the correct answer is still obtained,
+**                                  though perhaps more slowly.
+**
+**    OPTIMIZATION-IF-FALSE       - This branch is allowed to always be true
+**                                  and the correct answer is still obtained,
+**                                  though perhaps more slowly.
+**
+**    PREVENTS-HARMLESS-OVERREAD  - This branch prevents a buffer overread
+**                                  that would be harmless and undetectable
+**                                  if it did occur.
+**
+** In all cases, the special comment must be enclosed in the usual
+** slash-asterisk...asterisk-slash comment marks, with no spaces between the
+** asterisks and the comment text.
+*/
+
+/*
+** Make sure the Tcl calling convention macro is defined.  This macro is
+** only used by test code and Tcl integration code.
+*/
+#ifndef SQLITE_TCLAPI
+#  define SQLITE_TCLAPI
+#endif
+
+/*
+** Include the header file used to customize the compiler options for MSVC.
+** This should be done first so that it can successfully prevent spurious
+** compiler warnings due to subsequent content in this file and other files
+** that are included by this file.
+*/
+/************** Include msvc.h in the middle of sqliteInt.h ******************/
+/************** Begin file msvc.h ********************************************/
+/*
+** 2015 January 12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to MSVC.
+*/
+#ifndef SQLITE_MSVC_H
+#define SQLITE_MSVC_H
+
+#if defined(_MSC_VER)
+#pragma warning(disable : 4054)
+#pragma warning(disable : 4055)
+#pragma warning(disable : 4100)
+#pragma warning(disable : 4127)
+#pragma warning(disable : 4130)
+#pragma warning(disable : 4152)
+#pragma warning(disable : 4189)
+#pragma warning(disable : 4206)
+#pragma warning(disable : 4210)
+#pragma warning(disable : 4232)
+#pragma warning(disable : 4244)
+#pragma warning(disable : 4305)
+#pragma warning(disable : 4306)
+#pragma warning(disable : 4702)
+#pragma warning(disable : 4706)
+#endif /* defined(_MSC_VER) */
+
+#if defined(_MSC_VER) && !defined(_WIN64)
+#undef SQLITE_4_BYTE_ALIGNED_MALLOC
+#define SQLITE_4_BYTE_ALIGNED_MALLOC
+#endif /* defined(_MSC_VER) && !defined(_WIN64) */
+
+#if !defined(HAVE_LOG2) && defined(_MSC_VER) && _MSC_VER<1800
+#define HAVE_LOG2 0
+#endif /* !defined(HAVE_LOG2) && defined(_MSC_VER) && _MSC_VER<1800 */
+
+#endif /* SQLITE_MSVC_H */
+
+/************** End of msvc.h ************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/*
+** Special setup for VxWorks
+*/
+/************** Include vxworks.h in the middle of sqliteInt.h ***************/
+/************** Begin file vxworks.h *****************************************/
+/*
+** 2015-03-02
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to Wind River's VxWorks
+*/
+#if defined(__RTP__) || defined(_WRS_KERNEL)
+/* This is VxWorks.  Set up things specially for that OS
+*/
+#include <vxWorks.h>
+#include <pthread.h>  /* amalgamator: dontcache */
+#define OS_VXWORKS 1
+#define SQLITE_OS_OTHER 0
+#define SQLITE_HOMEGROWN_RECURSIVE_MUTEX 1
+#define SQLITE_OMIT_LOAD_EXTENSION 1
+#define SQLITE_ENABLE_LOCKING_STYLE 0
+#define HAVE_UTIME 1
+#else
+/* This is not VxWorks. */
+#define OS_VXWORKS 0
+#define HAVE_FCHOWN 1
+#define HAVE_READLINK 1
+#define HAVE_LSTAT 1
+#endif /* defined(_WRS_KERNEL) */
+
+/************** End of vxworks.h *********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/*
+** These #defines should enable >2GB file support on POSIX if the
+** underlying operating system supports it.  If the OS lacks
+** large file support, or if the OS is windows, these should be no-ops.
+**
+** Ticket #2739:  The _LARGEFILE_SOURCE macro must appear before any
+** system #includes.  Hence, this block of code must be the very first
+** code in all source files.
+**
+** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
+** on the compiler command line.  This is necessary if you are compiling
+** on a recent machine (ex: Red Hat 7.2) but you want your code to work
+** on an older machine (ex: Red Hat 6.0).  If you compile on Red Hat 7.2
+** without this option, LFS is enable.  But LFS does not exist in the kernel
+** in Red Hat 6.0, so the code won't work.  Hence, for maximum binary
+** portability you should omit LFS.
+**
+** The previous paragraph was written in 2005.  (This paragraph is written
+** on 2008-11-28.) These days, all Linux kernels support large files, so
+** you should probably leave LFS enabled.  But some embedded platforms might
+** lack LFS in which case the SQLITE_DISABLE_LFS macro might still be useful.
+**
+** Similar is true for Mac OS X.  LFS is only supported on Mac OS X 9 and later.
+*/
+#ifndef SQLITE_DISABLE_LFS
+# define _LARGE_FILE       1
+# ifndef _FILE_OFFSET_BITS
+#   define _FILE_OFFSET_BITS 64
+# endif
+# define _LARGEFILE_SOURCE 1
+#endif
+
+/* The GCC_VERSION and MSVC_VERSION macros are used to
+** conditionally include optimizations for each of these compilers.  A
+** value of 0 means that compiler is not being used.  The
+** SQLITE_DISABLE_INTRINSIC macro means do not use any compiler-specific
+** optimizations, and hence set all compiler macros to 0
+**
+** There was once also a CLANG_VERSION macro.  However, we learn that the
+** version numbers in clang are for "marketing" only and are inconsistent
+** and unreliable.  Fortunately, all versions of clang also recognize the
+** gcc version numbers and have reasonable settings for gcc version numbers,
+** so the GCC_VERSION macro will be set to a correct non-zero value even
+** when compiling with clang.
+*/
+#if defined(__GNUC__) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define GCC_VERSION (__GNUC__*1000000+__GNUC_MINOR__*1000+__GNUC_PATCHLEVEL__)
+#else
+# define GCC_VERSION 0
+#endif
+#if defined(_MSC_VER) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define MSVC_VERSION _MSC_VER
+#else
+# define MSVC_VERSION 0
+#endif
+
+/*
+** Some C99 functions in "math.h" are only present for MSVC when its version
+** is associated with Visual Studio 2013 or higher.
+*/
+#ifndef SQLITE_HAVE_C99_MATH_FUNCS
+# if MSVC_VERSION==0 || MSVC_VERSION>=1800
+#  define SQLITE_HAVE_C99_MATH_FUNCS (1)
+# else
+#  define SQLITE_HAVE_C99_MATH_FUNCS (0)
+# endif
+#endif
+
+/* Needed for various definitions... */
+#if defined(__GNUC__) && !defined(_GNU_SOURCE)
+# define _GNU_SOURCE
+#endif
+
+#if defined(__OpenBSD__) && !defined(_BSD_SOURCE)
+# define _BSD_SOURCE
+#endif
+
+/*
+** Macro to disable warnings about missing "break" at the end of a "case".
+*/
+#if defined(__has_attribute)
+#  if __has_attribute(fallthrough)
+#    define deliberate_fall_through __attribute__((fallthrough));
+#  endif
+#endif
+#if !defined(deliberate_fall_through)
+#  define deliberate_fall_through
+#endif
+
+/*
+** For MinGW, check to see if we can include the header file containing its
+** version information, among other things.  Normally, this internal MinGW
+** header file would [only] be included automatically by other MinGW header
+** files; however, the contained version information is now required by this
+** header file to work around binary compatibility issues (see below) and
+** this is the only known way to reliably obtain it.  This entire #if block
+** would be completely unnecessary if there was any other way of detecting
+** MinGW via their preprocessor (e.g. if they customized their GCC to define
+** some MinGW-specific macros).  When compiling for MinGW, either the
+** _HAVE_MINGW_H or _HAVE__MINGW_H (note the extra underscore) macro must be
+** defined; otherwise, detection of conditions specific to MinGW will be
+** disabled.
+*/
+#if defined(_HAVE_MINGW_H)
+# include "mingw.h"
+#elif defined(_HAVE__MINGW_H)
+# include "_mingw.h"
+#endif
+
+/*
+** For MinGW version 4.x (and higher), check to see if the _USE_32BIT_TIME_T
+** define is required to maintain binary compatibility with the MSVC runtime
+** library in use (e.g. for Windows XP).
+*/
+#if !defined(_USE_32BIT_TIME_T) && !defined(_USE_64BIT_TIME_T) && \
+    defined(_WIN32) && !defined(_WIN64) && \
+    defined(__MINGW_MAJOR_VERSION) && __MINGW_MAJOR_VERSION >= 4 && \
+    defined(__MSVCRT__)
+# define _USE_32BIT_TIME_T
+#endif
+
+/* Optionally #include a user-defined header, whereby compilation options
+** may be set prior to where they take effect, but after platform setup.
+** If SQLITE_CUSTOM_INCLUDE=? is defined, its value names the #include
+** file.
+*/
+#ifdef SQLITE_CUSTOM_INCLUDE
+# define INC_STRINGIFY_(f) #f
+# define INC_STRINGIFY(f) INC_STRINGIFY_(f)
+# include INC_STRINGIFY(SQLITE_CUSTOM_INCLUDE)
+#endif
+
+/* The public SQLite interface.  The _FILE_OFFSET_BITS macro must appear
+** first in QNX.  Also, the _USE_32BIT_TIME_T macro must appear first for
+** MinGW.
+*/
+/************** Include sqlite3.h in the middle of sqliteInt.h ***************/
+/************** Begin file sqlite3.h *****************************************/
+/*
+** 2001-09-15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the SQLite library
+** presents to client programs.  If a C-function, structure, datatype,
+** or constant definition does not appear in this file, then it is
+** not a published API of SQLite, is subject to change without
+** notice, and should not be referenced by programs that use SQLite.
+**
+** Some of the definitions that are in this file are marked as
+** "experimental".  Experimental interfaces are normally new
+** features recently added to SQLite.  We do not anticipate changes
+** to experimental interfaces but reserve the right to make minor changes
+** if experience from use "in the wild" suggest such changes are prudent.
+**
+** The official C-language API documentation for SQLite is derived
+** from comments in this file.  This file is the authoritative source
+** on how SQLite interfaces are supposed to operate.
+**
+** The name of this file under configuration management is "sqlite.h.in".
+** The makefile makes some minor changes to this file (such as inserting
+** the version number) and changes its name to "sqlite3.h" as
+** part of the build process.
+*/
+#ifndef SQLITE3_H
+#define SQLITE3_H
+#include <stdarg.h>     /* Needed for the definition of va_list */
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#if 0
+extern "C" {
+#endif
+
+
+/*
+** Facilitate override of interface linkage and calling conventions.
+** Be aware that these macros may not be used within this particular
+** translation of the amalgamation and its associated header file.
+**
+** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
+** compiler that the target identifier should have external linkage.
+**
+** The SQLITE_CDECL macro is used to set the calling convention for
+** public functions that accept a variable number of arguments.
+**
+** The SQLITE_APICALL macro is used to set the calling convention for
+** public functions that accept a fixed number of arguments.
+**
+** The SQLITE_STDCALL macro is no longer used and is now deprecated.
+**
+** The SQLITE_CALLBACK macro is used to set the calling convention for
+** function pointers.
+**
+** The SQLITE_SYSAPI macro is used to set the calling convention for
+** functions provided by the operating system.
+**
+** Currently, the SQLITE_CDECL, SQLITE_APICALL, SQLITE_CALLBACK, and
+** SQLITE_SYSAPI macros are used only when building for environments
+** that require non-default calling conventions.
+*/
+#ifndef SQLITE_EXTERN
+# define SQLITE_EXTERN extern
+#endif
+#ifndef SQLITE_API
+# define SQLITE_API
+#endif
+#ifndef SQLITE_CDECL
+# define SQLITE_CDECL
+#endif
+#ifndef SQLITE_APICALL
+# define SQLITE_APICALL
+#endif
+#ifndef SQLITE_STDCALL
+# define SQLITE_STDCALL SQLITE_APICALL
+#endif
+#ifndef SQLITE_CALLBACK
+# define SQLITE_CALLBACK
+#endif
+#ifndef SQLITE_SYSAPI
+# define SQLITE_SYSAPI
+#endif
+
+/*
+** These no-op macros are used in front of interfaces to mark those
+** interfaces as either deprecated or experimental.  New applications
+** should not use deprecated interfaces - they are supported for backwards
+** compatibility only.  Application writers should be aware that
+** experimental interfaces are subject to change in point releases.
+**
+** These macros used to resolve to various kinds of compiler magic that
+** would generate warning messages when they were used.  But that
+** compiler magic ended up generating such a flurry of bug reports
+** that we have taken it all out and gone back to using simple
+** noop macros.
+*/
+#define SQLITE_DEPRECATED
+#define SQLITE_EXPERIMENTAL
+
+/*
+** Ensure these symbols were not defined by some previous header file.
+*/
+#ifdef SQLITE_VERSION
+# undef SQLITE_VERSION
+#endif
+#ifdef SQLITE_VERSION_NUMBER
+# undef SQLITE_VERSION_NUMBER
+#endif
+
+/*
+** CAPI3REF: Compile-Time Library Version Numbers
+**
+** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
+** evaluates to a string literal that is the SQLite version in the
+** format "X.Y.Z" where X is the major version number (always 3 for
+** SQLite3) and Y is the minor version number and Z is the release number.)^
+** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
+** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
+** numbers used in [SQLITE_VERSION].)^
+** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
+** be larger than the release from which it is derived.  Either Y will
+** be held constant and Z will be incremented or else Y will be incremented
+** and Z will be reset to zero.
+**
+** Since [version 3.6.18] ([dateof:3.6.18]),
+** SQLite source code has been stored in the
+** <a href="http://www.fossil-scm.org/">Fossil configuration management
+** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
+** a string which identifies a particular check-in of SQLite
+** within its configuration management system.  ^The SQLITE_SOURCE_ID
+** string contains the date and time of the check-in (UTC) and a SHA1
+** or SHA3-256 hash of the entire source tree.  If the source code has
+** been edited in any way since it was last checked in, then the last
+** four hexadecimal digits of the hash may be modified.
+**
+** See also: [sqlite3_libversion()],
+** [sqlite3_libversion_number()], [sqlite3_sourceid()],
+** [sqlite_version()] and [sqlite_source_id()].
+*/
+#define SQLITE_VERSION        "3.49.2"
+#define SQLITE_VERSION_NUMBER 3049002
+#define SQLITE_SOURCE_ID      "2025-05-07 10:39:52 17144570b0d96ae63cd6f3edca39e27ebd74925252bbaf6723bcb2f6b4861fb1"
+
+/*
+** CAPI3REF: Run-Time Library Version Numbers
+** KEYWORDS: sqlite3_version sqlite3_sourceid
+**
+** These interfaces provide the same information as the [SQLITE_VERSION],
+** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
+** but are associated with the library instead of the header file.  ^(Cautious
+** programmers might include assert() statements in their application to
+** verify that values returned by these interfaces match the macros in
+** the header, and thus ensure that the application is
+** compiled with matching library and header files.
+**
+** <blockquote><pre>
+** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
+** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
+** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
+** </pre></blockquote>)^
+**
+** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
+** macro.  ^The sqlite3_libversion() function returns a pointer to the
+** to the sqlite3_version[] string constant.  The sqlite3_libversion()
+** function is provided for use in DLLs since DLL users usually do not have
+** direct access to string constants within the DLL.  ^The
+** sqlite3_libversion_number() function returns an integer equal to
+** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns
+** a pointer to a string constant whose value is the same as the
+** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
+** using an edited copy of [the amalgamation], then the last four characters
+** of the hash might be different from [SQLITE_SOURCE_ID].)^
+**
+** See also: [sqlite_version()] and [sqlite_source_id()].
+*/
+SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
+SQLITE_API const char *sqlite3_libversion(void);
+SQLITE_API const char *sqlite3_sourceid(void);
+SQLITE_API int sqlite3_libversion_number(void);
+
+/*
+** CAPI3REF: Run-Time Library Compilation Options Diagnostics
+**
+** ^The sqlite3_compileoption_used() function returns 0 or 1
+** indicating whether the specified option was defined at
+** compile time.  ^The SQLITE_ prefix may be omitted from the
+** option name passed to sqlite3_compileoption_used().
+**
+** ^The sqlite3_compileoption_get() function allows iterating
+** over the list of options that were defined at compile time by
+** returning the N-th compile time option string.  ^If N is out of range,
+** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
+** prefix is omitted from any strings returned by
+** sqlite3_compileoption_get().
+**
+** ^Support for the diagnostic functions sqlite3_compileoption_used()
+** and sqlite3_compileoption_get() may be omitted by specifying the
+** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
+**
+** See also: SQL functions [sqlite_compileoption_used()] and
+** [sqlite_compileoption_get()] and the [compile_options pragma].
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
+SQLITE_API const char *sqlite3_compileoption_get(int N);
+#else
+# define sqlite3_compileoption_used(X) 0
+# define sqlite3_compileoption_get(X)  ((void*)0)
+#endif
+
+/*
+** CAPI3REF: Test To See If The Library Is Threadsafe
+**
+** ^The sqlite3_threadsafe() function returns zero if and only if
+** SQLite was compiled with mutexing code omitted due to the
+** [SQLITE_THREADSAFE] compile-time option being set to 0.
+**
+** SQLite can be compiled with or without mutexes.  When
+** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
+** are enabled and SQLite is threadsafe.  When the
+** [SQLITE_THREADSAFE] macro is 0,
+** the mutexes are omitted.  Without the mutexes, it is not safe
+** to use SQLite concurrently from more than one thread.
+**
+** Enabling mutexes incurs a measurable performance penalty.
+** So if speed is of utmost importance, it makes sense to disable
+** the mutexes.  But for maximum safety, mutexes should be enabled.
+** ^The default behavior is for mutexes to be enabled.
+**
+** This interface can be used by an application to make sure that the
+** version of SQLite that it is linking against was compiled with
+** the desired setting of the [SQLITE_THREADSAFE] macro.
+**
+** This interface only reports on the compile-time mutex setting
+** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
+** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
+** can be fully or partially disabled using a call to [sqlite3_config()]
+** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
+** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
+** sqlite3_threadsafe() function shows only the compile-time setting of
+** thread safety, not any run-time changes to that setting made by
+** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
+** is unchanged by calls to sqlite3_config().)^
+**
+** See the [threading mode] documentation for additional information.
+*/
+SQLITE_API int sqlite3_threadsafe(void);
+
+/*
+** CAPI3REF: Database Connection Handle
+** KEYWORDS: {database connection} {database connections}
+**
+** Each open SQLite database is represented by a pointer to an instance of
+** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
+** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
+** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
+** and [sqlite3_close_v2()] are its destructors.  There are many other
+** interfaces (such as
+** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
+** [sqlite3_busy_timeout()] to name but three) that are methods on an
+** sqlite3 object.
+*/
+typedef struct sqlite3 sqlite3;
+
+/*
+** CAPI3REF: 64-Bit Integer Types
+** KEYWORDS: sqlite_int64 sqlite_uint64
+**
+** Because there is no cross-platform way to specify 64-bit integer types
+** SQLite includes typedefs for 64-bit signed and unsigned integers.
+**
+** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
+** The sqlite_int64 and sqlite_uint64 types are supported for backwards
+** compatibility only.
+**
+** ^The sqlite3_int64 and sqlite_int64 types can store integer values
+** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
+** sqlite3_uint64 and sqlite_uint64 types can store integer values
+** between 0 and +18446744073709551615 inclusive.
+*/
+#ifdef SQLITE_INT64_TYPE
+  typedef SQLITE_INT64_TYPE sqlite_int64;
+# ifdef SQLITE_UINT64_TYPE
+    typedef SQLITE_UINT64_TYPE sqlite_uint64;
+# else
+    typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
+# endif
+#elif defined(_MSC_VER) || defined(__BORLANDC__)
+  typedef __int64 sqlite_int64;
+  typedef unsigned __int64 sqlite_uint64;
+#else
+  typedef long long int sqlite_int64;
+  typedef unsigned long long int sqlite_uint64;
+#endif
+typedef sqlite_int64 sqlite3_int64;
+typedef sqlite_uint64 sqlite3_uint64;
+
+/*
+** If compiling for a processor that lacks floating point support,
+** substitute integer for floating-point.
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define double sqlite3_int64
+#endif
+
+/*
+** CAPI3REF: Closing A Database Connection
+** DESTRUCTOR: sqlite3
+**
+** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
+** for the [sqlite3] object.
+** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
+** the [sqlite3] object is successfully destroyed and all associated
+** resources are deallocated.
+**
+** Ideally, applications should [sqlite3_finalize | finalize] all
+** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
+** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
+** with the [sqlite3] object prior to attempting to close the object.
+** ^If the database connection is associated with unfinalized prepared
+** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
+** sqlite3_close() will leave the database connection open and return
+** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
+** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
+** it returns [SQLITE_OK] regardless, but instead of deallocating the database
+** connection immediately, it marks the database connection as an unusable
+** "zombie" and makes arrangements to automatically deallocate the database
+** connection after all prepared statements are finalized, all BLOB handles
+** are closed, and all backups have finished. The sqlite3_close_v2() interface
+** is intended for use with host languages that are garbage collected, and
+** where the order in which destructors are called is arbitrary.
+**
+** ^If an [sqlite3] object is destroyed while a transaction is open,
+** the transaction is automatically rolled back.
+**
+** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
+** must be either a NULL
+** pointer or an [sqlite3] object pointer obtained
+** from [sqlite3_open()], [sqlite3_open16()], or
+** [sqlite3_open_v2()], and not previously closed.
+** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
+** argument is a harmless no-op.
+*/
+SQLITE_API int sqlite3_close(sqlite3*);
+SQLITE_API int sqlite3_close_v2(sqlite3*);
+
+/*
+** The type for a callback function.
+** This is legacy and deprecated.  It is included for historical
+** compatibility and is not documented.
+*/
+typedef int (*sqlite3_callback)(void*,int,char**, char**);
+
+/*
+** CAPI3REF: One-Step Query Execution Interface
+** METHOD: sqlite3
+**
+** The sqlite3_exec() interface is a convenience wrapper around
+** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
+** that allows an application to run multiple statements of SQL
+** without having to use a lot of C code.
+**
+** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
+** semicolon-separate SQL statements passed into its 2nd argument,
+** in the context of the [database connection] passed in as its 1st
+** argument.  ^If the callback function of the 3rd argument to
+** sqlite3_exec() is not NULL, then it is invoked for each result row
+** coming out of the evaluated SQL statements.  ^The 4th argument to
+** sqlite3_exec() is relayed through to the 1st argument of each
+** callback invocation.  ^If the callback pointer to sqlite3_exec()
+** is NULL, then no callback is ever invoked and result rows are
+** ignored.
+**
+** ^If an error occurs while evaluating the SQL statements passed into
+** sqlite3_exec(), then execution of the current statement stops and
+** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
+** is not NULL then any error message is written into memory obtained
+** from [sqlite3_malloc()] and passed back through the 5th parameter.
+** To avoid memory leaks, the application should invoke [sqlite3_free()]
+** on error message strings returned through the 5th parameter of
+** sqlite3_exec() after the error message string is no longer needed.
+** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
+** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
+** NULL before returning.
+**
+** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
+** routine returns SQLITE_ABORT without invoking the callback again and
+** without running any subsequent SQL statements.
+**
+** ^The 2nd argument to the sqlite3_exec() callback function is the
+** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
+** callback is an array of pointers to strings obtained as if from
+** [sqlite3_column_text()], one for each column.  ^If an element of a
+** result row is NULL then the corresponding string pointer for the
+** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
+** sqlite3_exec() callback is an array of pointers to strings where each
+** entry represents the name of corresponding result column as obtained
+** from [sqlite3_column_name()].
+**
+** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
+** to an empty string, or a pointer that contains only whitespace and/or
+** SQL comments, then no SQL statements are evaluated and the database
+** is not changed.
+**
+** Restrictions:
+**
+** <ul>
+** <li> The application must ensure that the 1st parameter to sqlite3_exec()
+**      is a valid and open [database connection].
+** <li> The application must not close the [database connection] specified by
+**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not modify the SQL statement text passed into
+**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not dereference the arrays or string pointers
+**       passed as the 3rd and 4th callback parameters after it returns.
+** </ul>
+*/
+SQLITE_API int sqlite3_exec(
+  sqlite3*,                                  /* An open database */
+  const char *sql,                           /* SQL to be evaluated */
+  int (*callback)(void*,int,char**,char**),  /* Callback function */
+  void *,                                    /* 1st argument to callback */
+  char **errmsg                              /* Error msg written here */
+);
+
+/*
+** CAPI3REF: Result Codes
+** KEYWORDS: {result code definitions}
+**
+** Many SQLite functions return an integer result code from the set shown
+** here in order to indicate success or failure.
+**
+** New error codes may be added in future versions of SQLite.
+**
+** See also: [extended result code definitions]
+*/
+#define SQLITE_OK           0   /* Successful result */
+/* beginning-of-error-codes */
+#define SQLITE_ERROR        1   /* Generic error */
+#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
+#define SQLITE_PERM         3   /* Access permission denied */
+#define SQLITE_ABORT        4   /* Callback routine requested an abort */
+#define SQLITE_BUSY         5   /* The database file is locked */
+#define SQLITE_LOCKED       6   /* A table in the database is locked */
+#define SQLITE_NOMEM        7   /* A malloc() failed */
+#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
+#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
+#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
+#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
+#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
+#define SQLITE_FULL        13   /* Insertion failed because database is full */
+#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
+#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
+#define SQLITE_EMPTY       16   /* Internal use only */
+#define SQLITE_SCHEMA      17   /* The database schema changed */
+#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
+#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
+#define SQLITE_MISMATCH    20   /* Data type mismatch */
+#define SQLITE_MISUSE      21   /* Library used incorrectly */
+#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
+#define SQLITE_AUTH        23   /* Authorization denied */
+#define SQLITE_FORMAT      24   /* Not used */
+#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
+#define SQLITE_NOTADB      26   /* File opened that is not a database file */
+#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
+#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
+#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
+#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
+/* end-of-error-codes */
+
+/*
+** CAPI3REF: Extended Result Codes
+** KEYWORDS: {extended result code definitions}
+**
+** In its default configuration, SQLite API routines return one of 30 integer
+** [result codes].  However, experience has shown that many of
+** these result codes are too coarse-grained.  They do not provide as
+** much information about problems as programmers might like.  In an effort to
+** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
+** and later) include
+** support for additional result codes that provide more detailed information
+** about errors. These [extended result codes] are enabled or disabled
+** on a per database connection basis using the
+** [sqlite3_extended_result_codes()] API.  Or, the extended code for
+** the most recent error can be obtained using
+** [sqlite3_extended_errcode()].
+*/
+#define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
+#define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
+#define SQLITE_ERROR_SNAPSHOT          (SQLITE_ERROR | (3<<8))
+#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
+#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
+#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
+#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
+#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
+#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
+#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
+#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
+#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
+#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
+#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
+#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
+#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
+#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
+#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
+#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
+#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
+#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
+#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
+#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
+#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
+#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
+#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
+#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
+#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
+#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
+#define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
+#define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
+#define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
+#define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
+#define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
+#define SQLITE_IOERR_DATA              (SQLITE_IOERR | (32<<8))
+#define SQLITE_IOERR_CORRUPTFS         (SQLITE_IOERR | (33<<8))
+#define SQLITE_IOERR_IN_PAGE           (SQLITE_IOERR | (34<<8))
+#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
+#define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
+#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
+#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
+#define SQLITE_BUSY_TIMEOUT            (SQLITE_BUSY   |  (3<<8))
+#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
+#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
+#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
+#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
+#define SQLITE_CANTOPEN_DIRTYWAL       (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
+#define SQLITE_CANTOPEN_SYMLINK        (SQLITE_CANTOPEN | (6<<8))
+#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
+#define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
+#define SQLITE_CORRUPT_INDEX           (SQLITE_CORRUPT | (3<<8))
+#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
+#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
+#define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
+#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
+#define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
+#define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
+#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
+#define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
+#define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
+#define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
+#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
+#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
+#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
+#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
+#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
+#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
+#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
+#define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
+#define SQLITE_CONSTRAINT_DATATYPE     (SQLITE_CONSTRAINT |(12<<8))
+#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
+#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
+#define SQLITE_NOTICE_RBU              (SQLITE_NOTICE | (3<<8))
+#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
+#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
+#define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
+#define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8)) /* internal use only */
+
+/*
+** CAPI3REF: Flags For File Open Operations
+**
+** These bit values are intended for use in the
+** 3rd parameter to the [sqlite3_open_v2()] interface and
+** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
+**
+** Only those flags marked as "Ok for sqlite3_open_v2()" may be
+** used as the third argument to the [sqlite3_open_v2()] interface.
+** The other flags have historically been ignored by sqlite3_open_v2(),
+** though future versions of SQLite might change so that an error is
+** raised if any of the disallowed bits are passed into sqlite3_open_v2().
+** Applications should not depend on the historical behavior.
+**
+** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
+** [sqlite3_open_v2()] does *not* cause the underlying database file
+** to be opened using O_EXCL.  Passing SQLITE_OPEN_EXCLUSIVE into
+** [sqlite3_open_v2()] has historically be a no-op and might become an
+** error in future versions of SQLite.
+*/
+#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
+#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
+#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
+#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
+#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
+#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
+#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
+#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
+#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
+#define SQLITE_OPEN_SUPER_JOURNAL    0x00004000  /* VFS only */
+#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
+#define SQLITE_OPEN_NOFOLLOW         0x01000000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_EXRESCODE        0x02000000  /* Extended result codes */
+
+/* Reserved:                         0x00F00000 */
+/* Legacy compatibility: */
+#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
+
+
+/*
+** CAPI3REF: Device Characteristics
+**
+** The xDeviceCharacteristics method of the [sqlite3_io_methods]
+** object returns an integer which is a vector of these
+** bit values expressing I/O characteristics of the mass storage
+** device that holds the file that the [sqlite3_io_methods]
+** refers to.
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
+** after reboot following a crash or power loss, the only bytes in a
+** file that were written at the application level might have changed
+** and that adjacent bytes, even bytes within the same sector are
+** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
+** flag indicates that a file cannot be deleted when open.  The
+** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
+** read-only media and cannot be changed even by processes with
+** elevated privileges.
+**
+** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
+** filesystem supports doing multiple write operations atomically when those
+** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
+** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
+**
+** The SQLITE_IOCAP_SUBPAGE_READ property means that it is ok to read
+** from the database file in amounts that are not a multiple of the
+** page size and that do not begin at a page boundary.  Without this
+** property, SQLite is careful to only do full-page reads and write
+** on aligned pages, with the one exception that it will do a sub-page
+** read of the first page to access the database header.
+*/
+#define SQLITE_IOCAP_ATOMIC                 0x00000001
+#define SQLITE_IOCAP_ATOMIC512              0x00000002
+#define SQLITE_IOCAP_ATOMIC1K               0x00000004
+#define SQLITE_IOCAP_ATOMIC2K               0x00000008
+#define SQLITE_IOCAP_ATOMIC4K               0x00000010
+#define SQLITE_IOCAP_ATOMIC8K               0x00000020
+#define SQLITE_IOCAP_ATOMIC16K              0x00000040
+#define SQLITE_IOCAP_ATOMIC32K              0x00000080
+#define SQLITE_IOCAP_ATOMIC64K              0x00000100
+#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
+#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
+#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
+#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
+#define SQLITE_IOCAP_IMMUTABLE              0x00002000
+#define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
+#define SQLITE_IOCAP_SUBPAGE_READ           0x00008000
+
+/*
+** CAPI3REF: File Locking Levels
+**
+** SQLite uses one of these integer values as the second
+** argument to calls it makes to the xLock() and xUnlock() methods
+** of an [sqlite3_io_methods] object.  These values are ordered from
+** lest restrictive to most restrictive.
+**
+** The argument to xLock() is always SHARED or higher.  The argument to
+** xUnlock is either SHARED or NONE.
+*/
+#define SQLITE_LOCK_NONE          0       /* xUnlock() only */
+#define SQLITE_LOCK_SHARED        1       /* xLock() or xUnlock() */
+#define SQLITE_LOCK_RESERVED      2       /* xLock() only */
+#define SQLITE_LOCK_PENDING       3       /* xLock() only */
+#define SQLITE_LOCK_EXCLUSIVE     4       /* xLock() only */
+
+/*
+** CAPI3REF: Synchronization Type Flags
+**
+** When SQLite invokes the xSync() method of an
+** [sqlite3_io_methods] object it uses a combination of
+** these integer values as the second argument.
+**
+** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
+** sync operation only needs to flush data to mass storage.  Inode
+** information need not be flushed. If the lower four bits of the flag
+** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
+** If the lower four bits equal SQLITE_SYNC_FULL, that means
+** to use Mac OS X style fullsync instead of fsync().
+**
+** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
+** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
+** settings.  The [synchronous pragma] determines when calls to the
+** xSync VFS method occur and applies uniformly across all platforms.
+** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
+** energetic or rigorous or forceful the sync operations are and
+** only make a difference on Mac OSX for the default SQLite code.
+** (Third-party VFS implementations might also make the distinction
+** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
+** operating systems natively supported by SQLite, only Mac OSX
+** cares about the difference.)
+*/
+#define SQLITE_SYNC_NORMAL        0x00002
+#define SQLITE_SYNC_FULL          0x00003
+#define SQLITE_SYNC_DATAONLY      0x00010
+
+/*
+** CAPI3REF: OS Interface Open File Handle
+**
+** An [sqlite3_file] object represents an open file in the
+** [sqlite3_vfs | OS interface layer].  Individual OS interface
+** implementations will
+** want to subclass this object by appending additional fields
+** for their own use.  The pMethods entry is a pointer to an
+** [sqlite3_io_methods] object that defines methods for performing
+** I/O operations on the open file.
+*/
+typedef struct sqlite3_file sqlite3_file;
+struct sqlite3_file {
+  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
+};
+
+/*
+** CAPI3REF: OS Interface File Virtual Methods Object
+**
+** Every file opened by the [sqlite3_vfs.xOpen] method populates an
+** [sqlite3_file] object (or, more commonly, a subclass of the
+** [sqlite3_file] object) with a pointer to an instance of this object.
+** This object defines the methods used to perform various operations
+** against the open file represented by the [sqlite3_file] object.
+**
+** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
+** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
+** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
+** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
+** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
+** to NULL.
+**
+** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
+** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
+** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
+** flag may be ORed in to indicate that only the data of the file
+** and not its inode needs to be synced.
+**
+** The integer values to xLock() and xUnlock() are one of
+** <ul>
+** <li> [SQLITE_LOCK_NONE],
+** <li> [SQLITE_LOCK_SHARED],
+** <li> [SQLITE_LOCK_RESERVED],
+** <li> [SQLITE_LOCK_PENDING], or
+** <li> [SQLITE_LOCK_EXCLUSIVE].
+** </ul>
+** xLock() upgrades the database file lock.  In other words, xLock() moves the
+** database file lock in the direction NONE toward EXCLUSIVE. The argument to
+** xLock() is always one of SHARED, RESERVED, PENDING, or EXCLUSIVE, never
+** SQLITE_LOCK_NONE.  If the database file lock is already at or above the
+** requested lock, then the call to xLock() is a no-op.
+** xUnlock() downgrades the database file lock to either SHARED or NONE.
+** If the lock is already at or below the requested lock state, then the call
+** to xUnlock() is a no-op.
+** The xCheckReservedLock() method checks whether any database connection,
+** either in this process or in some other process, is holding a RESERVED,
+** PENDING, or EXCLUSIVE lock on the file.  It returns, via its output
+** pointer parameter, true if such a lock exists and false otherwise.
+**
+** The xFileControl() method is a generic interface that allows custom
+** VFS implementations to directly control an open file using the
+** [sqlite3_file_control()] interface.  The second "op" argument is an
+** integer opcode.  The third argument is a generic pointer intended to
+** point to a structure that may contain arguments or space in which to
+** write return values.  Potential uses for xFileControl() might be
+** functions to enable blocking locks with timeouts, to change the
+** locking strategy (for example to use dot-file locks), to inquire
+** about the status of a lock, or to break stale locks.  The SQLite
+** core reserves all opcodes less than 100 for its own use.
+** A [file control opcodes | list of opcodes] less than 100 is available.
+** Applications that define a custom xFileControl method should use opcodes
+** greater than 100 to avoid conflicts.  VFS implementations should
+** return [SQLITE_NOTFOUND] for file control opcodes that they do not
+** recognize.
+**
+** The xSectorSize() method returns the sector size of the
+** device that underlies the file.  The sector size is the
+** minimum write that can be performed without disturbing
+** other bytes in the file.  The xDeviceCharacteristics()
+** method returns a bit vector describing behaviors of the
+** underlying device:
+**
+** <ul>
+** <li> [SQLITE_IOCAP_ATOMIC]
+** <li> [SQLITE_IOCAP_ATOMIC512]
+** <li> [SQLITE_IOCAP_ATOMIC1K]
+** <li> [SQLITE_IOCAP_ATOMIC2K]
+** <li> [SQLITE_IOCAP_ATOMIC4K]
+** <li> [SQLITE_IOCAP_ATOMIC8K]
+** <li> [SQLITE_IOCAP_ATOMIC16K]
+** <li> [SQLITE_IOCAP_ATOMIC32K]
+** <li> [SQLITE_IOCAP_ATOMIC64K]
+** <li> [SQLITE_IOCAP_SAFE_APPEND]
+** <li> [SQLITE_IOCAP_SEQUENTIAL]
+** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
+** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
+** <li> [SQLITE_IOCAP_IMMUTABLE]
+** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
+** <li> [SQLITE_IOCAP_SUBPAGE_READ]
+** </ul>
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().
+**
+** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
+** in the unread portions of the buffer with zeros.  A VFS that
+** fails to zero-fill short reads might seem to work.  However,
+** failure to zero-fill short reads will eventually lead to
+** database corruption.
+*/
+typedef struct sqlite3_io_methods sqlite3_io_methods;
+struct sqlite3_io_methods {
+  int iVersion;
+  int (*xClose)(sqlite3_file*);
+  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
+  int (*xSync)(sqlite3_file*, int flags);
+  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
+  int (*xLock)(sqlite3_file*, int);
+  int (*xUnlock)(sqlite3_file*, int);
+  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
+  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
+  int (*xSectorSize)(sqlite3_file*);
+  int (*xDeviceCharacteristics)(sqlite3_file*);
+  /* Methods above are valid for version 1 */
+  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
+  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
+  void (*xShmBarrier)(sqlite3_file*);
+  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
+  /* Methods above are valid for version 2 */
+  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
+  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
+  /* Methods above are valid for version 3 */
+  /* Additional methods may be added in future releases */
+};
+
+/*
+** CAPI3REF: Standard File Control Opcodes
+** KEYWORDS: {file control opcodes} {file control opcode}
+**
+** These integer constants are opcodes for the xFileControl method
+** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
+** interface.
+**
+** <ul>
+** <li>[[SQLITE_FCNTL_LOCKSTATE]]
+** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
+** opcode causes the xFileControl method to write the current state of
+** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
+** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
+** into an integer that the pArg argument points to.
+** This capability is only available if SQLite is compiled with [SQLITE_DEBUG].
+**
+** <li>[[SQLITE_FCNTL_SIZE_HINT]]
+** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
+** layer a hint of how large the database file will grow to be during the
+** current transaction.  This hint is not guaranteed to be accurate but it
+** is often close.  The underlying VFS might choose to preallocate database
+** file space based on this hint in order to help writes to the database
+** file run faster.
+**
+** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
+** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
+** implements [sqlite3_deserialize()] to set an upper bound on the size
+** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
+** If the integer pointed to is negative, then it is filled in with the
+** current limit.  Otherwise the limit is set to the larger of the value
+** of the integer pointed to and the current database size.  The integer
+** pointed to is set to the new limit.
+**
+** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
+** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
+** extends and truncates the database file in chunks of a size specified
+** by the user. The fourth argument to [sqlite3_file_control()] should
+** point to an integer (type int) containing the new chunk-size to use
+** for the nominated database. Allocating database file space in large
+** chunks (say 1MB at a time), may reduce file-system fragmentation and
+** improve performance on some systems.
+**
+** <li>[[SQLITE_FCNTL_FILE_POINTER]]
+** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with a particular database
+** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
+**
+** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
+** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with the journal file (either
+** the [rollback journal] or the [write-ahead log]) for a particular database
+** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
+**
+** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
+** No longer in use.
+**
+** <li>[[SQLITE_FCNTL_SYNC]]
+** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
+** sent to the VFS immediately before the xSync method is invoked on a
+** database file descriptor. Or, if the xSync method is not invoked
+** because the user has configured SQLite with
+** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
+** of the xSync method. In most cases, the pointer argument passed with
+** this file-control is NULL. However, if the database file is being synced
+** as part of a multi-database commit, the argument points to a nul-terminated
+** string containing the transactions super-journal file name. VFSes that
+** do not need this signal should silently ignore this opcode. Applications
+** should not call [sqlite3_file_control()] with this opcode as doing so may
+** disrupt the operation of the specialized VFSes that do require it.
+**
+** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
+** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
+** and sent to the VFS after a transaction has been committed immediately
+** but before the database is unlocked. VFSes that do not need this signal
+** should silently ignore this opcode. Applications should not call
+** [sqlite3_file_control()] with this opcode as doing so may disrupt the
+** operation of the specialized VFSes that do require it.
+**
+** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
+** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
+** retry counts and intervals for certain disk I/O operations for the
+** windows [VFS] in order to provide robustness in the presence of
+** anti-virus programs.  By default, the windows VFS will retry file read,
+** file write, and file delete operations up to 10 times, with a delay
+** of 25 milliseconds before the first retry and with the delay increasing
+** by an additional 25 milliseconds with each subsequent retry.  This
+** opcode allows these two values (10 retries and 25 milliseconds of delay)
+** to be adjusted.  The values are changed for all database connections
+** within the same process.  The argument is a pointer to an array of two
+** integers where the first integer is the new retry count and the second
+** integer is the delay.  If either integer is negative, then the setting
+** is not changed but instead the prior value of that setting is written
+** into the array entry, allowing the current retry settings to be
+** interrogated.  The zDbName parameter is ignored.
+**
+** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
+** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
+** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
+** write ahead log ([WAL file]) and shared memory
+** files used for transaction control
+** are automatically deleted when the latest connection to the database
+** closes.  Setting persistent WAL mode causes those files to persist after
+** close.  Persisting the files is useful when other processes that do not
+** have write permission on the directory containing the database file want
+** to read the database file, as the WAL and shared memory files must exist
+** in order for the database to be readable.  The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
+** WAL mode.  If the integer is -1, then it is overwritten with the current
+** WAL persistence setting.
+**
+** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
+** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
+** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
+** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
+** xDeviceCharacteristics methods. The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
+** mode.  If the integer is -1, then it is overwritten with the current
+** zero-damage mode setting.
+**
+** <li>[[SQLITE_FCNTL_OVERWRITE]]
+** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
+** a write transaction to indicate that, unless it is rolled back for some
+** reason, the entire database file will be overwritten by the current
+** transaction. This is used by VACUUM operations.
+**
+** <li>[[SQLITE_FCNTL_VFSNAME]]
+** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
+** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
+** final bottom-level VFS are written into memory obtained from
+** [sqlite3_malloc()] and the result is stored in the char* variable
+** that the fourth parameter of [sqlite3_file_control()] points to.
+** The caller is responsible for freeing the memory when done.  As with
+** all file-control actions, there is no guarantee that this will actually
+** do anything.  Callers should initialize the char* variable to a NULL
+** pointer in case this file-control is not implemented.  This file-control
+** is intended for diagnostic use only.
+**
+** <li>[[SQLITE_FCNTL_VFS_POINTER]]
+** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
+** [VFSes] currently in use.  ^(The argument X in
+** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
+** of type "[sqlite3_vfs] **".  This opcodes will set *X
+** to a pointer to the top-level VFS.)^
+** ^When there are multiple VFS shims in the stack, this opcode finds the
+** upper-most shim only.
+**
+** <li>[[SQLITE_FCNTL_PRAGMA]]
+** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
+** file control is sent to the open [sqlite3_file] object corresponding
+** to the database file to which the pragma statement refers. ^The argument
+** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
+** pointers to strings (char**) in which the second element of the array
+** is the name of the pragma and the third element is the argument to the
+** pragma or NULL if the pragma has no argument.  ^The handler for an
+** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
+** of the char** argument point to a string obtained from [sqlite3_mprintf()]
+** or the equivalent and that string will become the result of the pragma or
+** the error message if the pragma fails. ^If the
+** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
+** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
+** file control returns [SQLITE_OK], then the parser assumes that the
+** VFS has handled the PRAGMA itself and the parser generates a no-op
+** prepared statement if result string is NULL, or that returns a copy
+** of the result string if the string is non-NULL.
+** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
+** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
+** that the VFS encountered an error while handling the [PRAGMA] and the
+** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
+** file control occurs at the beginning of pragma statement analysis and so
+** it is able to override built-in [PRAGMA] statements.
+**
+** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
+** ^The [SQLITE_FCNTL_BUSYHANDLER]
+** file-control may be invoked by SQLite on the database file handle
+** shortly after it is opened in order to provide a custom VFS with access
+** to the connection's busy-handler callback. The argument is of type (void**)
+** - an array of two (void *) values. The first (void *) actually points
+** to a function of type (int (*)(void *)). In order to invoke the connection's
+** busy-handler, this function should be invoked with the second (void *) in
+** the array as the only argument. If it returns non-zero, then the operation
+** should be retried. If it returns zero, the custom VFS should abandon the
+** current operation.
+**
+** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
+** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
+** to have SQLite generate a
+** temporary filename using the same algorithm that is followed to generate
+** temporary filenames for TEMP tables and other internal uses.  The
+** argument should be a char** which will be filled with the filename
+** written into memory obtained from [sqlite3_malloc()].  The caller should
+** invoke [sqlite3_free()] on the result to avoid a memory leak.
+**
+** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
+** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
+** maximum number of bytes that will be used for memory-mapped I/O.
+** The argument is a pointer to a value of type sqlite3_int64 that
+** is an advisory maximum number of bytes in the file to memory map.  The
+** pointer is overwritten with the old value.  The limit is not changed if
+** the value originally pointed to is negative, and so the current limit
+** can be queried by passing in a pointer to a negative number.  This
+** file-control is used internally to implement [PRAGMA mmap_size].
+**
+** <li>[[SQLITE_FCNTL_TRACE]]
+** The [SQLITE_FCNTL_TRACE] file control provides advisory information
+** to the VFS about what the higher layers of the SQLite stack are doing.
+** This file control is used by some VFS activity tracing [shims].
+** The argument is a zero-terminated string.  Higher layers in the
+** SQLite stack may generate instances of this file control if
+** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
+**
+** <li>[[SQLITE_FCNTL_HAS_MOVED]]
+** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
+** pointer to an integer and it writes a boolean into that integer depending
+** on whether or not the file has been renamed, moved, or deleted since it
+** was first opened.
+**
+** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
+** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
+** underlying native file handle associated with a file handle.  This file
+** control interprets its argument as a pointer to a native file handle and
+** writes the resulting value there.
+**
+** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
+** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
+** opcode causes the xFileControl method to swap the file handle with the one
+** pointed to by the pArg argument.  This capability is used during testing
+** and only needs to be supported when SQLITE_TEST is defined.
+**
+** <li>[[SQLITE_FCNTL_NULL_IO]]
+** The [SQLITE_FCNTL_NULL_IO] opcode sets the low-level file descriptor
+** or file handle for the [sqlite3_file] object such that it will no longer
+** read or write to the database file.
+**
+** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
+** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
+** be advantageous to block on the next WAL lock if the lock is not immediately
+** available.  The WAL subsystem issues this signal during rare
+** circumstances in order to fix a problem with priority inversion.
+** Applications should <em>not</em> use this file-control.
+**
+** <li>[[SQLITE_FCNTL_ZIPVFS]]
+** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
+** VFS should return SQLITE_NOTFOUND for this opcode.
+**
+** <li>[[SQLITE_FCNTL_RBU]]
+** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
+** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
+** this opcode.
+**
+** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
+** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
+** the file descriptor is placed in "batch write mode", which
+** means all subsequent write operations will be deferred and done
+** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
+** that do not support batch atomic writes will return SQLITE_NOTFOUND.
+** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
+** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
+** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
+** no VFS interface calls on the same [sqlite3_file] file descriptor
+** except for calls to the xWrite method and the xFileControl method
+** with [SQLITE_FCNTL_SIZE_HINT].
+**
+** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
+** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
+** operations since the previous successful call to
+** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
+** This file control returns [SQLITE_OK] if and only if the writes were
+** all performed successfully and have been committed to persistent storage.
+** ^Regardless of whether or not it is successful, this file control takes
+** the file descriptor out of batch write mode so that all subsequent
+** write operations are independent.
+** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
+** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
+**
+** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
+** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
+** operations since the previous successful call to
+** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
+** ^This file control takes the file descriptor out of batch write mode
+** so that all subsequent write operations are independent.
+** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
+** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
+**
+** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
+** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
+** to block for up to M milliseconds before failing when attempting to
+** obtain a file lock using the xLock or xShmLock methods of the VFS.
+** The parameter is a pointer to a 32-bit signed integer that contains
+** the value that M is to be set to. Before returning, the 32-bit signed
+** integer is overwritten with the previous value of M.
+**
+** <li>[[SQLITE_FCNTL_DATA_VERSION]]
+** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
+** a database file.  The argument is a pointer to a 32-bit unsigned integer.
+** The "data version" for the pager is written into the pointer.  The
+** "data version" changes whenever any change occurs to the corresponding
+** database file, either through SQL statements on the same database
+** connection or through transactions committed by separate database
+** connections possibly in other processes. The [sqlite3_total_changes()]
+** interface can be used to find if any database on the connection has changed,
+** but that interface responds to changes on TEMP as well as MAIN and does
+** not provide a mechanism to detect changes to MAIN only.  Also, the
+** [sqlite3_total_changes()] interface responds to internal changes only and
+** omits changes made by other database connections.  The
+** [PRAGMA data_version] command provides a mechanism to detect changes to
+** a single attached database that occur due to other database connections,
+** but omits changes implemented by the database connection on which it is
+** called.  This file control is the only mechanism to detect changes that
+** happen either internally or externally and that are associated with
+** a particular attached database.
+**
+** <li>[[SQLITE_FCNTL_CKPT_START]]
+** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
+** in wal mode before the client starts to copy pages from the wal
+** file to the database file.
+**
+** <li>[[SQLITE_FCNTL_CKPT_DONE]]
+** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
+** in wal mode after the client has finished copying pages from the wal
+** file to the database file, but before the *-shm file is updated to
+** record the fact that the pages have been checkpointed.
+**
+** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
+** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
+** whether or not there is a database client in another process with a wal-mode
+** transaction open on the database or not. It is only available on unix.The
+** (void*) argument passed with this file-control should be a pointer to a
+** value of type (int). The integer value is set to 1 if the database is a wal
+** mode database and there exists at least one client in another process that
+** currently has an SQL transaction open on the database. It is set to 0 if
+** the database is not a wal-mode db, or if there is no such connection in any
+** other process. This opcode cannot be used to detect transactions opened
+** by clients within the current process, only within other processes.
+**
+** <li>[[SQLITE_FCNTL_CKSM_FILE]]
+** The [SQLITE_FCNTL_CKSM_FILE] opcode is for use internally by the
+** [checksum VFS shim] only.
+**
+** <li>[[SQLITE_FCNTL_RESET_CACHE]]
+** If there is currently no transaction open on the database, and the
+** database is not a temp db, then the [SQLITE_FCNTL_RESET_CACHE] file-control
+** purges the contents of the in-memory page cache. If there is an open
+** transaction, or if the db is a temp-db, this opcode is a no-op, not an error.
+** </ul>
+*/
+#define SQLITE_FCNTL_LOCKSTATE               1
+#define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
+#define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
+#define SQLITE_FCNTL_LAST_ERRNO              4
+#define SQLITE_FCNTL_SIZE_HINT               5
+#define SQLITE_FCNTL_CHUNK_SIZE              6
+#define SQLITE_FCNTL_FILE_POINTER            7
+#define SQLITE_FCNTL_SYNC_OMITTED            8
+#define SQLITE_FCNTL_WIN32_AV_RETRY          9
+#define SQLITE_FCNTL_PERSIST_WAL            10
+#define SQLITE_FCNTL_OVERWRITE              11
+#define SQLITE_FCNTL_VFSNAME                12
+#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
+#define SQLITE_FCNTL_PRAGMA                 14
+#define SQLITE_FCNTL_BUSYHANDLER            15
+#define SQLITE_FCNTL_TEMPFILENAME           16
+#define SQLITE_FCNTL_MMAP_SIZE              18
+#define SQLITE_FCNTL_TRACE                  19
+#define SQLITE_FCNTL_HAS_MOVED              20
+#define SQLITE_FCNTL_SYNC                   21
+#define SQLITE_FCNTL_COMMIT_PHASETWO        22
+#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
+#define SQLITE_FCNTL_WAL_BLOCK              24
+#define SQLITE_FCNTL_ZIPVFS                 25
+#define SQLITE_FCNTL_RBU                    26
+#define SQLITE_FCNTL_VFS_POINTER            27
+#define SQLITE_FCNTL_JOURNAL_POINTER        28
+#define SQLITE_FCNTL_WIN32_GET_HANDLE       29
+#define SQLITE_FCNTL_PDB                    30
+#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
+#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
+#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
+#define SQLITE_FCNTL_LOCK_TIMEOUT           34
+#define SQLITE_FCNTL_DATA_VERSION           35
+#define SQLITE_FCNTL_SIZE_LIMIT             36
+#define SQLITE_FCNTL_CKPT_DONE              37
+#define SQLITE_FCNTL_RESERVE_BYTES          38
+#define SQLITE_FCNTL_CKPT_START             39
+#define SQLITE_FCNTL_EXTERNAL_READER        40
+#define SQLITE_FCNTL_CKSM_FILE              41
+#define SQLITE_FCNTL_RESET_CACHE            42
+#define SQLITE_FCNTL_NULL_IO                43
+
+/* deprecated names */
+#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
+#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
+#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
+
+
+/*
+** CAPI3REF: Mutex Handle
+**
+** The mutex module within SQLite defines [sqlite3_mutex] to be an
+** abstract type for a mutex object.  The SQLite core never looks
+** at the internal representation of an [sqlite3_mutex].  It only
+** deals with pointers to the [sqlite3_mutex] object.
+**
+** Mutexes are created using [sqlite3_mutex_alloc()].
+*/
+typedef struct sqlite3_mutex sqlite3_mutex;
+
+/*
+** CAPI3REF: Loadable Extension Thunk
+**
+** A pointer to the opaque sqlite3_api_routines structure is passed as
+** the third parameter to entry points of [loadable extensions].  This
+** structure must be typedefed in order to work around compiler warnings
+** on some platforms.
+*/
+typedef struct sqlite3_api_routines sqlite3_api_routines;
+
+/*
+** CAPI3REF: File Name
+**
+** Type [sqlite3_filename] is used by SQLite to pass filenames to the
+** xOpen method of a [VFS]. It may be cast to (const char*) and treated
+** as a normal, nul-terminated, UTF-8 buffer containing the filename, but
+** may also be passed to special APIs such as:
+**
+** <ul>
+** <li>  sqlite3_filename_database()
+** <li>  sqlite3_filename_journal()
+** <li>  sqlite3_filename_wal()
+** <li>  sqlite3_uri_parameter()
+** <li>  sqlite3_uri_boolean()
+** <li>  sqlite3_uri_int64()
+** <li>  sqlite3_uri_key()
+** </ul>
+*/
+typedef const char *sqlite3_filename;
+
+/*
+** CAPI3REF: OS Interface Object
+**
+** An instance of the sqlite3_vfs object defines the interface between
+** the SQLite core and the underlying operating system.  The "vfs"
+** in the name of the object stands for "virtual file system".  See
+** the [VFS | VFS documentation] for further information.
+**
+** The VFS interface is sometimes extended by adding new methods onto
+** the end.  Each time such an extension occurs, the iVersion field
+** is incremented.  The iVersion value started out as 1 in
+** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
+** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
+** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
+** may be appended to the sqlite3_vfs object and the iVersion value
+** may increase again in future versions of SQLite.
+** Note that due to an oversight, the structure
+** of the sqlite3_vfs object changed in the transition from
+** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
+** and yet the iVersion field was not increased.
+**
+** The szOsFile field is the size of the subclassed [sqlite3_file]
+** structure used by this VFS.  mxPathname is the maximum length of
+** a pathname in this VFS.
+**
+** Registered sqlite3_vfs objects are kept on a linked list formed by
+** the pNext pointer.  The [sqlite3_vfs_register()]
+** and [sqlite3_vfs_unregister()] interfaces manage this list
+** in a thread-safe way.  The [sqlite3_vfs_find()] interface
+** searches the list.  Neither the application code nor the VFS
+** implementation should use the pNext pointer.
+**
+** The pNext field is the only field in the sqlite3_vfs
+** structure that SQLite will ever modify.  SQLite will only access
+** or modify this field while holding a particular static mutex.
+** The application should never modify anything within the sqlite3_vfs
+** object once the object has been registered.
+**
+** The zName field holds the name of the VFS module.  The name must
+** be unique across all VFS modules.
+**
+** [[sqlite3_vfs.xOpen]]
+** ^SQLite guarantees that the zFilename parameter to xOpen
+** is either a NULL pointer or string obtained
+** from xFullPathname() with an optional suffix added.
+** ^If a suffix is added to the zFilename parameter, it will
+** consist of a single "-" character followed by no more than
+** 11 alphanumeric and/or "-" characters.
+** ^SQLite further guarantees that
+** the string will be valid and unchanged until xClose() is
+** called. Because of the previous sentence,
+** the [sqlite3_file] can safely store a pointer to the
+** filename if it needs to remember the filename for some reason.
+** If the zFilename parameter to xOpen is a NULL pointer then xOpen
+** must invent its own temporary name for the file.  ^Whenever the
+** xFilename parameter is NULL it will also be the case that the
+** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
+**
+** The flags argument to xOpen() includes all bits set in
+** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
+** or [sqlite3_open16()] is used, then flags includes at least
+** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
+** If xOpen() opens a file read-only then it sets *pOutFlags to
+** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
+**
+** ^(SQLite will also add one of the following flags to the xOpen()
+** call, depending on the object being opened:
+**
+** <ul>
+** <li>  [SQLITE_OPEN_MAIN_DB]
+** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
+** <li>  [SQLITE_OPEN_TEMP_DB]
+** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
+** <li>  [SQLITE_OPEN_TRANSIENT_DB]
+** <li>  [SQLITE_OPEN_SUBJOURNAL]
+** <li>  [SQLITE_OPEN_SUPER_JOURNAL]
+** <li>  [SQLITE_OPEN_WAL]
+** </ul>)^
+**
+** The file I/O implementation can use the object type flags to
+** change the way it deals with files.  For example, an application
+** that does not care about crash recovery or rollback might make
+** the open of a journal file a no-op.  Writes to this journal would
+** also be no-ops, and any attempt to read the journal would return
+** SQLITE_IOERR.  Or the implementation might recognize that a database
+** file will be doing page-aligned sector reads and writes in a random
+** order and set up its I/O subsystem accordingly.
+**
+** SQLite might also add one of the following flags to the xOpen method:
+**
+** <ul>
+** <li> [SQLITE_OPEN_DELETEONCLOSE]
+** <li> [SQLITE_OPEN_EXCLUSIVE]
+** </ul>
+**
+** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
+** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
+** will be set for TEMP databases and their journals, transient
+** databases, and subjournals.
+**
+** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
+** with the [SQLITE_OPEN_CREATE] flag, which are both directly
+** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
+** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
+** SQLITE_OPEN_CREATE, is used to indicate that file should always
+** be created, and that it is an error if it already exists.
+** It is <i>not</i> used to indicate the file should be opened
+** for exclusive access.
+**
+** ^At least szOsFile bytes of memory are allocated by SQLite
+** to hold the [sqlite3_file] structure passed as the third
+** argument to xOpen.  The xOpen method does not have to
+** allocate the structure; it should just fill it in.  Note that
+** the xOpen method must set the sqlite3_file.pMethods to either
+** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
+** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
+** element will be valid after xOpen returns regardless of the success
+** or failure of the xOpen call.
+**
+** [[sqlite3_vfs.xAccess]]
+** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
+** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
+** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
+** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
+** flag is never actually used and is not implemented in the built-in
+** VFSes of SQLite.  The file is named by the second argument and can be a
+** directory. The xAccess method returns [SQLITE_OK] on success or some
+** non-zero error code if there is an I/O error or if the name of
+** the file given in the second argument is illegal.  If SQLITE_OK
+** is returned, then non-zero or zero is written into *pResOut to indicate
+** whether or not the file is accessible.
+**
+** ^SQLite will always allocate at least mxPathname+1 bytes for the
+** output buffer xFullPathname.  The exact size of the output buffer
+** is also passed as a parameter to both  methods. If the output buffer
+** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
+** handled as a fatal error by SQLite, vfs implementations should endeavor
+** to prevent this by setting mxPathname to a sufficiently large value.
+**
+** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
+** interfaces are not strictly a part of the filesystem, but they are
+** included in the VFS structure for completeness.
+** The xRandomness() function attempts to return nBytes bytes
+** of good-quality randomness into zOut.  The return value is
+** the actual number of bytes of randomness obtained.
+** The xSleep() method causes the calling thread to sleep for at
+** least the number of microseconds given.  ^The xCurrentTime()
+** method returns a Julian Day Number for the current date and time as
+** a floating point value.
+** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
+** Day Number multiplied by 86400000 (the number of milliseconds in
+** a 24-hour day).
+** ^SQLite will use the xCurrentTimeInt64() method to get the current
+** date and time if that method is available (if iVersion is 2 or
+** greater and the function pointer is not NULL) and will fall back
+** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
+**
+** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
+** are not used by the SQLite core.  These optional interfaces are provided
+** by some VFSes to facilitate testing of the VFS code. By overriding
+** system calls with functions under its control, a test program can
+** simulate faults and error conditions that would otherwise be difficult
+** or impossible to induce.  The set of system calls that can be overridden
+** varies from one VFS to another, and from one version of the same VFS to the
+** next.  Applications that use these interfaces must be prepared for any
+** or all of these interfaces to be NULL or for their behavior to change
+** from one release to the next.  Applications must not attempt to access
+** any of these methods if the iVersion of the VFS is less than 3.
+*/
+typedef struct sqlite3_vfs sqlite3_vfs;
+typedef void (*sqlite3_syscall_ptr)(void);
+struct sqlite3_vfs {
+  int iVersion;            /* Structure version number (currently 3) */
+  int szOsFile;            /* Size of subclassed sqlite3_file */
+  int mxPathname;          /* Maximum file pathname length */
+  sqlite3_vfs *pNext;      /* Next registered VFS */
+  const char *zName;       /* Name of this virtual file system */
+  void *pAppData;          /* Pointer to application-specific data */
+  int (*xOpen)(sqlite3_vfs*, sqlite3_filename zName, sqlite3_file*,
+               int flags, int *pOutFlags);
+  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
+  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
+  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
+  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
+  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
+  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
+  void (*xDlClose)(sqlite3_vfs*, void*);
+  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
+  int (*xSleep)(sqlite3_vfs*, int microseconds);
+  int (*xCurrentTime)(sqlite3_vfs*, double*);
+  int (*xGetLastError)(sqlite3_vfs*, int, char *);
+  /*
+  ** The methods above are in version 1 of the sqlite_vfs object
+  ** definition.  Those that follow are added in version 2 or later
+  */
+  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
+  /*
+  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
+  ** Those below are for version 3 and greater.
+  */
+  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
+  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
+  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
+  /*
+  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
+  ** New fields may be appended in future versions.  The iVersion
+  ** value will increment whenever this happens.
+  */
+};
+
+/*
+** CAPI3REF: Flags for the xAccess VFS method
+**
+** These integer constants can be used as the third parameter to
+** the xAccess method of an [sqlite3_vfs] object.  They determine
+** what kind of permissions the xAccess method is looking for.
+** With SQLITE_ACCESS_EXISTS, the xAccess method
+** simply checks whether the file exists.
+** With SQLITE_ACCESS_READWRITE, the xAccess method
+** checks whether the named directory is both readable and writable
+** (in other words, if files can be added, removed, and renamed within
+** the directory).
+** The SQLITE_ACCESS_READWRITE constant is currently used only by the
+** [temp_store_directory pragma], though this could change in a future
+** release of SQLite.
+** With SQLITE_ACCESS_READ, the xAccess method
+** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
+** currently unused, though it might be used in a future release of
+** SQLite.
+*/
+#define SQLITE_ACCESS_EXISTS    0
+#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
+#define SQLITE_ACCESS_READ      2   /* Unused */
+
+/*
+** CAPI3REF: Flags for the xShmLock VFS method
+**
+** These integer constants define the various locking operations
+** allowed by the xShmLock method of [sqlite3_io_methods].  The
+** following are the only legal combinations of flags to the
+** xShmLock method:
+**
+** <ul>
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
+** </ul>
+**
+** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
+** was given on the corresponding lock.
+**
+** The xShmLock method can transition between unlocked and SHARED or
+** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
+** and EXCLUSIVE.
+*/
+#define SQLITE_SHM_UNLOCK       1
+#define SQLITE_SHM_LOCK         2
+#define SQLITE_SHM_SHARED       4
+#define SQLITE_SHM_EXCLUSIVE    8
+
+/*
+** CAPI3REF: Maximum xShmLock index
+**
+** The xShmLock method on [sqlite3_io_methods] may use values
+** between 0 and this upper bound as its "offset" argument.
+** The SQLite core will never attempt to acquire or release a
+** lock outside of this range
+*/
+#define SQLITE_SHM_NLOCK        8
+
+
+/*
+** CAPI3REF: Initialize The SQLite Library
+**
+** ^The sqlite3_initialize() routine initializes the
+** SQLite library.  ^The sqlite3_shutdown() routine
+** deallocates any resources that were allocated by sqlite3_initialize().
+** These routines are designed to aid in process initialization and
+** shutdown on embedded systems.  Workstation applications using
+** SQLite normally do not need to invoke either of these routines.
+**
+** A call to sqlite3_initialize() is an "effective" call if it is
+** the first time sqlite3_initialize() is invoked during the lifetime of
+** the process, or if it is the first time sqlite3_initialize() is invoked
+** following a call to sqlite3_shutdown().  ^(Only an effective call
+** of sqlite3_initialize() does any initialization.  All other calls
+** are harmless no-ops.)^
+**
+** A call to sqlite3_shutdown() is an "effective" call if it is the first
+** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
+** an effective call to sqlite3_shutdown() does any deinitialization.
+** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
+**
+** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
+** is not.  The sqlite3_shutdown() interface must only be called from a
+** single thread.  All open [database connections] must be closed and all
+** other SQLite resources must be deallocated prior to invoking
+** sqlite3_shutdown().
+**
+** Among other things, ^sqlite3_initialize() will invoke
+** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
+** will invoke sqlite3_os_end().
+**
+** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
+** ^If for some reason, sqlite3_initialize() is unable to initialize
+** the library (perhaps it is unable to allocate a needed resource such
+** as a mutex) it returns an [error code] other than [SQLITE_OK].
+**
+** ^The sqlite3_initialize() routine is called internally by many other
+** SQLite interfaces so that an application usually does not need to
+** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
+** calls sqlite3_initialize() so the SQLite library will be automatically
+** initialized when [sqlite3_open()] is called if it has not be initialized
+** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
+** compile-time option, then the automatic calls to sqlite3_initialize()
+** are omitted and the application must call sqlite3_initialize() directly
+** prior to using any other SQLite interface.  For maximum portability,
+** it is recommended that applications always invoke sqlite3_initialize()
+** directly prior to using any other SQLite interface.  Future releases
+** of SQLite may require this.  In other words, the behavior exhibited
+** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
+** default behavior in some future release of SQLite.
+**
+** The sqlite3_os_init() routine does operating-system specific
+** initialization of the SQLite library.  The sqlite3_os_end()
+** routine undoes the effect of sqlite3_os_init().  Typical tasks
+** performed by these routines include allocation or deallocation
+** of static resources, initialization of global variables,
+** setting up a default [sqlite3_vfs] module, or setting up
+** a default configuration using [sqlite3_config()].
+**
+** The application should never invoke either sqlite3_os_init()
+** or sqlite3_os_end() directly.  The application should only invoke
+** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
+** interface is called automatically by sqlite3_initialize() and
+** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
+** implementations for sqlite3_os_init() and sqlite3_os_end()
+** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
+** When [custom builds | built for other platforms]
+** (using the [SQLITE_OS_OTHER=1] compile-time
+** option) the application must supply a suitable implementation for
+** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
+** implementation of sqlite3_os_init() or sqlite3_os_end()
+** must return [SQLITE_OK] on success and some other [error code] upon
+** failure.
+*/
+SQLITE_API int sqlite3_initialize(void);
+SQLITE_API int sqlite3_shutdown(void);
+SQLITE_API int sqlite3_os_init(void);
+SQLITE_API int sqlite3_os_end(void);
+
+/*
+** CAPI3REF: Configuring The SQLite Library
+**
+** The sqlite3_config() interface is used to make global configuration
+** changes to SQLite in order to tune SQLite to the specific needs of
+** the application.  The default configuration is recommended for most
+** applications and so this routine is usually not necessary.  It is
+** provided to support rare applications with unusual needs.
+**
+** <b>The sqlite3_config() interface is not threadsafe. The application
+** must ensure that no other SQLite interfaces are invoked by other
+** threads while sqlite3_config() is running.</b>
+**
+** The first argument to sqlite3_config() is an integer
+** [configuration option] that determines
+** what property of SQLite is to be configured.  Subsequent arguments
+** vary depending on the [configuration option]
+** in the first argument.
+**
+** For most configuration options, the sqlite3_config() interface
+** may only be invoked prior to library initialization using
+** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
+** The exceptional configuration options that may be invoked at any time
+** are called "anytime configuration options".
+** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
+** [sqlite3_shutdown()] with a first argument that is not an anytime
+** configuration option, then the sqlite3_config() call will return SQLITE_MISUSE.
+** Note, however, that ^sqlite3_config() can be called as part of the
+** implementation of an application-defined [sqlite3_os_init()].
+**
+** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
+** ^If the option is unknown or SQLite is unable to set the option
+** then this routine returns a non-zero [error code].
+*/
+SQLITE_API int sqlite3_config(int, ...);
+
+/*
+** CAPI3REF: Configure database connections
+** METHOD: sqlite3
+**
+** The sqlite3_db_config() interface is used to make configuration
+** changes to a [database connection].  The interface is similar to
+** [sqlite3_config()] except that the changes apply to a single
+** [database connection] (specified in the first argument).
+**
+** The second argument to sqlite3_db_config(D,V,...)  is the
+** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
+** that indicates what aspect of the [database connection] is being configured.
+** Subsequent arguments vary depending on the configuration verb.
+**
+** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
+** the call is considered successful.
+*/
+SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Memory Allocation Routines
+**
+** An instance of this object defines the interface between SQLite
+** and low-level memory allocation routines.
+**
+** This object is used in only one place in the SQLite interface.
+** A pointer to an instance of this object is the argument to
+** [sqlite3_config()] when the configuration option is
+** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
+** By creating an instance of this object
+** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
+** during configuration, an application can specify an alternative
+** memory allocation subsystem for SQLite to use for all of its
+** dynamic memory needs.
+**
+** Note that SQLite comes with several [built-in memory allocators]
+** that are perfectly adequate for the overwhelming majority of applications
+** and that this object is only useful to a tiny minority of applications
+** with specialized memory allocation requirements.  This object is
+** also used during testing of SQLite in order to specify an alternative
+** memory allocator that simulates memory out-of-memory conditions in
+** order to verify that SQLite recovers gracefully from such
+** conditions.
+**
+** The xMalloc, xRealloc, and xFree methods must work like the
+** malloc(), realloc() and free() functions from the standard C library.
+** ^SQLite guarantees that the second argument to
+** xRealloc is always a value returned by a prior call to xRoundup.
+**
+** xSize should return the allocated size of a memory allocation
+** previously obtained from xMalloc or xRealloc.  The allocated size
+** is always at least as big as the requested size but may be larger.
+**
+** The xRoundup method returns what would be the allocated size of
+** a memory allocation given a particular requested size.  Most memory
+** allocators round up memory allocations at least to the next multiple
+** of 8.  Some allocators round up to a larger multiple or to a power of 2.
+** Every memory allocation request coming in through [sqlite3_malloc()]
+** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
+** that causes the corresponding memory allocation to fail.
+**
+** The xInit method initializes the memory allocator.  For example,
+** it might allocate any required mutexes or initialize internal data
+** structures.  The xShutdown method is invoked (indirectly) by
+** [sqlite3_shutdown()] and should deallocate any resources acquired
+** by xInit.  The pAppData pointer is used as the only parameter to
+** xInit and xShutdown.
+**
+** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
+** the xInit method, so the xInit method need not be threadsafe.  The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  For all other methods, SQLite
+** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
+** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
+** it is by default) and so the methods are automatically serialized.
+** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
+** methods must be threadsafe or else make their own arrangements for
+** serialization.
+**
+** SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+*/
+typedef struct sqlite3_mem_methods sqlite3_mem_methods;
+struct sqlite3_mem_methods {
+  void *(*xMalloc)(int);         /* Memory allocation function */
+  void (*xFree)(void*);          /* Free a prior allocation */
+  void *(*xRealloc)(void*,int);  /* Resize an allocation */
+  int (*xSize)(void*);           /* Return the size of an allocation */
+  int (*xRoundup)(int);          /* Round up request size to allocation size */
+  int (*xInit)(void*);           /* Initialize the memory allocator */
+  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
+  void *pAppData;                /* Argument to xInit() and xShutdown() */
+};
+
+/*
+** CAPI3REF: Configuration Options
+** KEYWORDS: {configuration option}
+**
+** These constants are the available integer configuration options that
+** can be passed as the first argument to the [sqlite3_config()] interface.
+**
+** Most of the configuration options for sqlite3_config()
+** will only work if invoked prior to [sqlite3_initialize()] or after
+** [sqlite3_shutdown()].  The few exceptions to this rule are called
+** "anytime configuration options".
+** ^Calling [sqlite3_config()] with a first argument that is not an
+** anytime configuration option in between calls to [sqlite3_initialize()] and
+** [sqlite3_shutdown()] is a no-op that returns SQLITE_MISUSE.
+**
+** The set of anytime configuration options can change (by insertions
+** and/or deletions) from one release of SQLite to the next.
+** As of SQLite version 3.42.0, the complete set of anytime configuration
+** options is:
+** <ul>
+** <li> SQLITE_CONFIG_LOG
+** <li> SQLITE_CONFIG_PCACHE_HDRSZ
+** </ul>
+**
+** New configuration options may be added in future releases of SQLite.
+** Existing configuration options might be discontinued.  Applications
+** should check the return code from [sqlite3_config()] to make sure that
+** the call worked.  The [sqlite3_config()] interface will return a
+** non-zero [error code] if a discontinued or unsupported configuration option
+** is invoked.
+**
+** <dl>
+** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Single-thread.  In other words, it disables
+** all mutexing and puts SQLite into a mode where it can only be used
+** by a single thread.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to change the [threading mode] from its default
+** value of Single-thread and so [sqlite3_config()] will return
+** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
+** configuration option.</dd>
+**
+** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Multi-thread.  In other words, it disables
+** mutexing on [database connection] and [prepared statement] objects.
+** The application is responsible for serializing access to
+** [database connections] and [prepared statements].  But other mutexes
+** are enabled so that SQLite will be safe to use in a multi-threaded
+** environment as long as no two threads attempt to use the same
+** [database connection] at the same time.  ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Multi-thread [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
+**
+** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Serialized. In other words, this option enables
+** all mutexes including the recursive
+** mutexes on [database connection] and [prepared statement] objects.
+** In this mode (which is the default when SQLite is compiled with
+** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
+** to [database connections] and [prepared statements] so that the
+** application is free to use the same [database connection] or the
+** same [prepared statement] in different threads at the same time.
+** ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Serialized [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
+**
+** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
+** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
+** a pointer to an instance of the [sqlite3_mem_methods] structure.
+** The argument specifies
+** alternative low-level memory allocation routines to be used in place of
+** the memory allocation routines built into SQLite.)^ ^SQLite makes
+** its own private copy of the content of the [sqlite3_mem_methods] structure
+** before the [sqlite3_config()] call returns.</dd>
+**
+** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
+** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
+** is a pointer to an instance of the [sqlite3_mem_methods] structure.
+** The [sqlite3_mem_methods]
+** structure is filled with the currently defined memory allocation routines.)^
+** This option can be used to overload the default memory allocation
+** routines with a wrapper that simulations memory allocation failure or
+** tracks memory usage, for example. </dd>
+**
+** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
+** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
+** type int, interpreted as a boolean, which if true provides a hint to
+** SQLite that it should avoid large memory allocations if possible.
+** SQLite will run faster if it is free to make large memory allocations,
+** but some application might prefer to run slower in exchange for
+** guarantees about memory fragmentation that are possible if large
+** allocations are avoided.  This hint is normally off.
+** </dd>
+**
+** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
+** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
+** interpreted as a boolean, which enables or disables the collection of
+** memory allocation statistics. ^(When memory allocation statistics are
+** disabled, the following SQLite interfaces become non-operational:
+**   <ul>
+**   <li> [sqlite3_hard_heap_limit64()]
+**   <li> [sqlite3_memory_used()]
+**   <li> [sqlite3_memory_highwater()]
+**   <li> [sqlite3_soft_heap_limit64()]
+**   <li> [sqlite3_status64()]
+**   </ul>)^
+** ^Memory allocation statistics are enabled by default unless SQLite is
+** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
+** allocation statistics are disabled by default.
+** </dd>
+**
+** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
+** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
+** </dd>
+**
+** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
+** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
+** that SQLite can use for the database page cache with the default page
+** cache implementation.
+** This configuration option is a no-op if an application-defined page
+** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
+** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
+** 8-byte aligned memory (pMem), the size of each page cache line (sz),
+** and the number of cache lines (N).
+** The sz argument should be the size of the largest database page
+** (a power of two between 512 and 65536) plus some extra bytes for each
+** page header.  ^The number of extra bytes needed by the page header
+** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
+** ^It is harmless, apart from the wasted memory,
+** for the sz parameter to be larger than necessary.  The pMem
+** argument must be either a NULL pointer or a pointer to an 8-byte
+** aligned block of memory of at least sz*N bytes, otherwise
+** subsequent behavior is undefined.
+** ^When pMem is not NULL, SQLite will strive to use the memory provided
+** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
+** a page cache line is larger than sz bytes or if all of the pMem buffer
+** is exhausted.
+** ^If pMem is NULL and N is non-zero, then each database connection
+** does an initial bulk allocation for page cache memory
+** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
+** of -1024*N bytes if N is negative, . ^If additional
+** page cache memory is needed beyond what is provided by the initial
+** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
+** additional cache line. </dd>
+**
+** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
+** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
+** that SQLite will use for all of its dynamic memory allocation needs
+** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
+** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
+** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
+** [SQLITE_ERROR] if invoked otherwise.
+** ^There are three arguments to SQLITE_CONFIG_HEAP:
+** An 8-byte aligned pointer to the memory,
+** the number of bytes in the memory buffer, and the minimum allocation size.
+** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
+** to using its default memory allocator (the system malloc() implementation),
+** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
+** memory pointer is not NULL then the alternative memory
+** allocator is engaged to handle all of SQLites memory allocation needs.
+** The first pointer (the memory pointer) must be aligned to an 8-byte
+** boundary or subsequent behavior of SQLite will be undefined.
+** The minimum allocation size is capped at 2**12. Reasonable values
+** for the minimum allocation size are 2**5 through 2**8.</dd>
+**
+** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
+** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
+** pointer to an instance of the [sqlite3_mutex_methods] structure.
+** The argument specifies alternative low-level mutex routines to be used
+** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
+** the content of the [sqlite3_mutex_methods] structure before the call to
+** [sqlite3_config()] returns. ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
+**
+** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
+** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
+** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
+** [sqlite3_mutex_methods]
+** structure is filled with the currently defined mutex routines.)^
+** This option can be used to overload the default mutex allocation
+** routines with a wrapper used to track mutex usage for performance
+** profiling or testing, for example.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
+**
+** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
+** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
+** the default size of lookaside memory on each [database connection].
+** The first argument is the
+** size of each lookaside buffer slot and the second is the number of
+** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
+** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
+** option to [sqlite3_db_config()] can be used to change the lookaside
+** configuration on individual connections.)^ </dd>
+**
+** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
+** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
+** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
+** the interface to a custom page cache implementation.)^
+** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
+**
+** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
+** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
+** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
+** the current page cache implementation into that object.)^ </dd>
+**
+** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
+** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
+** global [error log].
+** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
+** function with a call signature of void(*)(void*,int,const char*),
+** and a pointer to void. ^If the function pointer is not NULL, it is
+** invoked by [sqlite3_log()] to process each logging event.  ^If the
+** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
+** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
+** passed through as the first parameter to the application-defined logger
+** function whenever that function is invoked.  ^The second parameter to
+** the logger function is a copy of the first parameter to the corresponding
+** [sqlite3_log()] call and is intended to be a [result code] or an
+** [extended result code].  ^The third parameter passed to the logger is
+** log message after formatting via [sqlite3_snprintf()].
+** The SQLite logging interface is not reentrant; the logger function
+** supplied by the application must not invoke any SQLite interface.
+** In a multi-threaded application, the application-defined logger
+** function must be threadsafe. </dd>
+**
+** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
+** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
+** If non-zero, then URI handling is globally enabled. If the parameter is zero,
+** then URI handling is globally disabled.)^ ^If URI handling is globally
+** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
+** [sqlite3_open16()] or
+** specified as part of [ATTACH] commands are interpreted as URIs, regardless
+** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
+** connection is opened. ^If it is globally disabled, filenames are
+** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
+** database connection is opened. ^(By default, URI handling is globally
+** disabled. The default value may be changed by compiling with the
+** [SQLITE_USE_URI] symbol defined.)^
+**
+** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
+** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
+** argument which is interpreted as a boolean in order to enable or disable
+** the use of covering indices for full table scans in the query optimizer.
+** ^The default setting is determined
+** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
+** if that compile-time option is omitted.
+** The ability to disable the use of covering indices for full table scans
+** is because some incorrectly coded legacy applications might malfunction
+** when the optimization is enabled.  Providing the ability to
+** disable the optimization allows the older, buggy application code to work
+** without change even with newer versions of SQLite.
+**
+** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
+** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
+** <dd> These options are obsolete and should not be used by new code.
+** They are retained for backwards compatibility but are now no-ops.
+** </dd>
+**
+** [[SQLITE_CONFIG_SQLLOG]]
+** <dt>SQLITE_CONFIG_SQLLOG
+** <dd>This option is only available if sqlite is compiled with the
+** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
+** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
+** The second should be of type (void*). The callback is invoked by the library
+** in three separate circumstances, identified by the value passed as the
+** fourth parameter. If the fourth parameter is 0, then the database connection
+** passed as the second argument has just been opened. The third argument
+** points to a buffer containing the name of the main database file. If the
+** fourth parameter is 1, then the SQL statement that the third parameter
+** points to has just been executed. Or, if the fourth parameter is 2, then
+** the connection being passed as the second parameter is being closed. The
+** third parameter is passed NULL In this case.  An example of using this
+** configuration option can be seen in the "test_sqllog.c" source file in
+** the canonical SQLite source tree.</dd>
+**
+** [[SQLITE_CONFIG_MMAP_SIZE]]
+** <dt>SQLITE_CONFIG_MMAP_SIZE
+** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
+** that are the default mmap size limit (the default setting for
+** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
+** ^The default setting can be overridden by each database connection using
+** either the [PRAGMA mmap_size] command, or by using the
+** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
+** will be silently truncated if necessary so that it does not exceed the
+** compile-time maximum mmap size set by the
+** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
+** ^If either argument to this option is negative, then that argument is
+** changed to its compile-time default.
+**
+** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
+** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
+** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
+** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
+** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
+** that specifies the maximum size of the created heap.
+**
+** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
+** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
+** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
+** is a pointer to an integer and writes into that integer the number of extra
+** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
+** The amount of extra space required can change depending on the compiler,
+** target platform, and SQLite version.
+**
+** [[SQLITE_CONFIG_PMASZ]]
+** <dt>SQLITE_CONFIG_PMASZ
+** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
+** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
+** sorter to that integer.  The default minimum PMA Size is set by the
+** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
+** to help with sort operations when multithreaded sorting
+** is enabled (using the [PRAGMA threads] command) and the amount of content
+** to be sorted exceeds the page size times the minimum of the
+** [PRAGMA cache_size] setting and this value.
+**
+** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
+** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
+** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
+** becomes the [statement journal] spill-to-disk threshold.
+** [Statement journals] are held in memory until their size (in bytes)
+** exceeds this threshold, at which point they are written to disk.
+** Or if the threshold is -1, statement journals are always held
+** exclusively in memory.
+** Since many statement journals never become large, setting the spill
+** threshold to a value such as 64KiB can greatly reduce the amount of
+** I/O required to support statement rollback.
+** The default value for this setting is controlled by the
+** [SQLITE_STMTJRNL_SPILL] compile-time option.
+**
+** [[SQLITE_CONFIG_SORTERREF_SIZE]]
+** <dt>SQLITE_CONFIG_SORTERREF_SIZE
+** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
+** of type (int) - the new value of the sorter-reference size threshold.
+** Usually, when SQLite uses an external sort to order records according
+** to an ORDER BY clause, all fields required by the caller are present in the
+** sorted records. However, if SQLite determines based on the declared type
+** of a table column that its values are likely to be very large - larger
+** than the configured sorter-reference size threshold - then a reference
+** is stored in each sorted record and the required column values loaded
+** from the database as records are returned in sorted order. The default
+** value for this option is to never use this optimization. Specifying a
+** negative value for this option restores the default behavior.
+** This option is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
+**
+** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
+** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
+** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
+** [sqlite3_int64] parameter which is the default maximum size for an in-memory
+** database created using [sqlite3_deserialize()].  This default maximum
+** size can be adjusted up or down for individual databases using the
+** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
+** configuration setting is never used, then the default maximum is determined
+** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
+** compile-time option is not set, then the default maximum is 1073741824.
+**
+** [[SQLITE_CONFIG_ROWID_IN_VIEW]]
+** <dt>SQLITE_CONFIG_ROWID_IN_VIEW
+** <dd>The SQLITE_CONFIG_ROWID_IN_VIEW option enables or disables the ability
+** for VIEWs to have a ROWID.  The capability can only be enabled if SQLite is
+** compiled with -DSQLITE_ALLOW_ROWID_IN_VIEW, in which case the capability
+** defaults to on.  This configuration option queries the current setting or
+** changes the setting to off or on.  The argument is a pointer to an integer.
+** If that integer initially holds a value of 1, then the ability for VIEWs to
+** have ROWIDs is activated.  If the integer initially holds zero, then the
+** ability is deactivated.  Any other initial value for the integer leaves the
+** setting unchanged.  After changes, if any, the integer is written with
+** a 1 or 0, if the ability for VIEWs to have ROWIDs is on or off.  If SQLite
+** is compiled without -DSQLITE_ALLOW_ROWID_IN_VIEW (which is the usual and
+** recommended case) then the integer is always filled with zero, regardless
+** if its initial value.
+** </dl>
+*/
+#define SQLITE_CONFIG_SINGLETHREAD         1  /* nil */
+#define SQLITE_CONFIG_MULTITHREAD          2  /* nil */
+#define SQLITE_CONFIG_SERIALIZED           3  /* nil */
+#define SQLITE_CONFIG_MALLOC               4  /* sqlite3_mem_methods* */
+#define SQLITE_CONFIG_GETMALLOC            5  /* sqlite3_mem_methods* */
+#define SQLITE_CONFIG_SCRATCH              6  /* No longer used */
+#define SQLITE_CONFIG_PAGECACHE            7  /* void*, int sz, int N */
+#define SQLITE_CONFIG_HEAP                 8  /* void*, int nByte, int min */
+#define SQLITE_CONFIG_MEMSTATUS            9  /* boolean */
+#define SQLITE_CONFIG_MUTEX               10  /* sqlite3_mutex_methods* */
+#define SQLITE_CONFIG_GETMUTEX            11  /* sqlite3_mutex_methods* */
+/* previously SQLITE_CONFIG_CHUNKALLOC    12 which is now unused. */
+#define SQLITE_CONFIG_LOOKASIDE           13  /* int int */
+#define SQLITE_CONFIG_PCACHE              14  /* no-op */
+#define SQLITE_CONFIG_GETPCACHE           15  /* no-op */
+#define SQLITE_CONFIG_LOG                 16  /* xFunc, void* */
+#define SQLITE_CONFIG_URI                 17  /* int */
+#define SQLITE_CONFIG_PCACHE2             18  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_GETPCACHE2          19  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
+#define SQLITE_CONFIG_SQLLOG              21  /* xSqllog, void* */
+#define SQLITE_CONFIG_MMAP_SIZE           22  /* sqlite3_int64, sqlite3_int64 */
+#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
+#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
+#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
+#define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
+#define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
+#define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
+#define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
+#define SQLITE_CONFIG_ROWID_IN_VIEW       30  /* int* */
+
+/*
+** CAPI3REF: Database Connection Configuration Options
+**
+** These constants are the available integer configuration options that
+** can be passed as the second parameter to the [sqlite3_db_config()] interface.
+**
+** The [sqlite3_db_config()] interface is a var-args functions.  It takes a
+** variable number of parameters, though always at least two.  The number of
+** parameters passed into sqlite3_db_config() depends on which of these
+** constants is given as the second parameter.  This documentation page
+** refers to parameters beyond the second as "arguments".  Thus, when this
+** page says "the N-th argument" it means "the N-th parameter past the
+** configuration option" or "the (N+2)-th parameter to sqlite3_db_config()".
+**
+** New configuration options may be added in future releases of SQLite.
+** Existing configuration options might be discontinued.  Applications
+** should check the return code from [sqlite3_db_config()] to make sure that
+** the call worked.  ^The [sqlite3_db_config()] interface will return a
+** non-zero [error code] if a discontinued or unsupported configuration option
+** is invoked.
+**
+** <dl>
+** [[SQLITE_DBCONFIG_LOOKASIDE]]
+** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
+** <dd> The SQLITE_DBCONFIG_LOOKASIDE option is used to adjust the
+** configuration of the lookaside memory allocator within a database
+** connection.
+** The arguments to the SQLITE_DBCONFIG_LOOKASIDE option are <i>not</i>
+** in the [DBCONFIG arguments|usual format].
+** The SQLITE_DBCONFIG_LOOKASIDE option takes three arguments, not two,
+** so that a call to [sqlite3_db_config()] that uses SQLITE_DBCONFIG_LOOKASIDE
+** should have a total of five parameters.
+** ^The first argument (the third parameter to [sqlite3_db_config()] is a
+** pointer to a memory buffer to use for lookaside memory.
+** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
+** may be NULL in which case SQLite will allocate the
+** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
+** size of each lookaside buffer slot.  ^The third argument is the number of
+** slots.  The size of the buffer in the first argument must be greater than
+** or equal to the product of the second and third arguments.  The buffer
+** must be aligned to an 8-byte boundary.  ^If the second argument to
+** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
+** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
+** configuration for a database connection can only be changed when that
+** connection is not currently using lookaside memory, or in other words
+** when the "current value" returned by
+** [sqlite3_db_status](D,[SQLITE_DBSTATUS_LOOKASIDE_USED],...) is zero.
+** Any attempt to change the lookaside memory configuration when lookaside
+** memory is in use leaves the configuration unchanged and returns
+** [SQLITE_BUSY].)^</dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
+** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
+** <dd> ^This option is used to enable or disable the enforcement of
+** [foreign key constraints].  This is the same setting that is
+** enabled or disabled by the [PRAGMA foreign_keys] statement.
+** The first argument is an integer which is 0 to disable FK enforcement,
+** positive to enable FK enforcement or negative to leave FK enforcement
+** unchanged.  The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether FK enforcement is off or on
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the FK enforcement setting is not reported back. </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
+** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
+** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
+** There should be two additional arguments.
+** The first argument is an integer which is 0 to disable triggers,
+** positive to enable triggers or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether triggers are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the trigger setting is not reported back.
+**
+** <p>Originally this option disabled all triggers.  ^(However, since
+** SQLite version 3.35.0, TEMP triggers are still allowed even if
+** this option is off.  So, in other words, this option now only disables
+** triggers in the main database schema or in the schemas of [ATTACH]-ed
+** databases.)^ </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
+** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
+** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
+** There must be two additional arguments.
+** The first argument is an integer which is 0 to disable views,
+** positive to enable views or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether views are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the view setting is not reported back.
+**
+** <p>Originally this option disabled all views.  ^(However, since
+** SQLite version 3.35.0, TEMP views are still allowed even if
+** this option is off.  So, in other words, this option now only disables
+** views in the main database schema or in the schemas of ATTACH-ed
+** databases.)^ </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
+** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
+** <dd> ^This option is used to enable or disable the
+** [fts3_tokenizer()] function which is part of the
+** [FTS3] full-text search engine extension.
+** There must be two additional arguments.
+** The first argument is an integer which is 0 to disable fts3_tokenizer() or
+** positive to enable fts3_tokenizer() or negative to leave the setting
+** unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the new setting is not reported back. </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
+** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
+** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
+** interface independently of the [load_extension()] SQL function.
+** The [sqlite3_enable_load_extension()] API enables or disables both the
+** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
+** There must be two additional arguments.
+** When the first argument to this interface is 1, then only the C-API is
+** enabled and the SQL function remains disabled.  If the first argument to
+** this interface is 0, then both the C-API and the SQL function are disabled.
+** If the first argument is -1, then no changes are made to state of either the
+** C-API or the SQL function.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
+** is disabled or enabled following this call.  The second parameter may
+** be a NULL pointer, in which case the new setting is not reported back.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
+** <dd> ^This option is used to change the name of the "main" database
+** schema.  This option does not follow the
+** [DBCONFIG arguments|usual SQLITE_DBCONFIG argument format].
+** This option takes exactly one additional argument so that the
+** [sqlite3_db_config()] call has a total of three parameters.  The
+** extra argument must be a pointer to a constant UTF8 string which
+** will become the new schema name in place of "main".  ^SQLite does
+** not make a copy of the new main schema name string, so the application
+** must ensure that the argument passed into SQLITE_DBCONFIG MAINDBNAME
+** is unchanged until after the database connection closes.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
+** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
+** <dd> Usually, when a database in [WAL mode] is closed or detached from a
+** database handle, SQLite checks if if there are other connections to the
+** same database, and if there are no other database connection (if the
+** connection being closed is the last open connection to the database),
+** then SQLite performs a [checkpoint] before closing the connection and
+** deletes the WAL file.  The SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE option can
+** be used to override that behavior. The first argument passed to this
+** operation (the third parameter to [sqlite3_db_config()]) is an integer
+** which is positive to disable checkpoints-on-close, or zero (the default)
+** to enable them, and negative to leave the setting unchanged.
+** The second argument (the fourth parameter) is a pointer to an integer
+** into which is written 0 or 1 to indicate whether checkpoints-on-close
+** have been disabled - 0 if they are not disabled, 1 if they are.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
+** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
+** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
+** a single SQL query statement will always use the same algorithm regardless
+** of values of [bound parameters].)^ The QPSG disables some query optimizations
+** that look at the values of bound parameters, which can make some queries
+** slower.  But the QPSG has the advantage of more predictable behavior.  With
+** the QPSG active, SQLite will always use the same query plan in the field as
+** was used during testing in the lab.
+** The first argument to this setting is an integer which is 0 to disable
+** the QPSG, positive to enable QPSG, or negative to leave the setting
+** unchanged. The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
+** following this call.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
+** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
+** include output for any operations performed by trigger programs. This
+** option is used to set or clear (the default) a flag that governs this
+** behavior. The first parameter passed to this operation is an integer -
+** positive to enable output for trigger programs, or zero to disable it,
+** or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which is written
+** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
+** it is not disabled, 1 if it is.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
+** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
+** [VACUUM] in order to reset a database back to an empty database
+** with no schema and no content. The following process works even for
+** a badly corrupted database file:
+** <ol>
+** <li> If the database connection is newly opened, make sure it has read the
+**      database schema by preparing then discarding some query against the
+**      database, or calling sqlite3_table_column_metadata(), ignoring any
+**      errors.  This step is only necessary if the application desires to keep
+**      the database in WAL mode after the reset if it was in WAL mode before
+**      the reset.
+** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
+** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
+** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
+** </ol>
+** Because resetting a database is destructive and irreversible, the
+** process requires the use of this obscure API and multiple steps to
+** help ensure that it does not happen by accident. Because this
+** feature must be capable of resetting corrupt databases, and
+** shutting down virtual tables may require access to that corrupt
+** storage, the library must abandon any installed virtual tables
+** without calling their xDestroy() methods.
+**
+** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
+** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
+** "defensive" flag for a database connection.  When the defensive
+** flag is enabled, language features that allow ordinary SQL to
+** deliberately corrupt the database file are disabled.  The disabled
+** features include but are not limited to the following:
+** <ul>
+** <li> The [PRAGMA writable_schema=ON] statement.
+** <li> The [PRAGMA journal_mode=OFF] statement.
+** <li> The [PRAGMA schema_version=N] statement.
+** <li> Writes to the [sqlite_dbpage] virtual table.
+** <li> Direct writes to [shadow tables].
+** </ul>
+** </dd>
+**
+** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
+** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
+** "writable_schema" flag. This has the same effect and is logically equivalent
+** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
+** The first argument to this setting is an integer which is 0 to disable
+** the writable_schema, positive to enable writable_schema, or negative to
+** leave the setting unchanged. The second parameter is a pointer to an
+** integer into which is written 0 or 1 to indicate whether the writable_schema
+** is enabled or disabled following this call.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
+** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
+** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
+** the legacy behavior of the [ALTER TABLE RENAME] command such it
+** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
+** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
+** additional information. This feature can also be turned on and off
+** using the [PRAGMA legacy_alter_table] statement.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_DQS_DML]]
+** <dt>SQLITE_DBCONFIG_DQS_DML</dt>
+** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
+** the legacy [double-quoted string literal] misfeature for DML statements
+** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
+** default value of this setting is determined by the [-DSQLITE_DQS]
+** compile-time option.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_DQS_DDL]]
+** <dt>SQLITE_DBCONFIG_DQS_DDL</dt>
+** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
+** the legacy [double-quoted string literal] misfeature for DDL statements,
+** such as CREATE TABLE and CREATE INDEX. The
+** default value of this setting is determined by the [-DSQLITE_DQS]
+** compile-time option.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
+** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</dt>
+** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
+** assume that database schemas are untainted by malicious content.
+** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
+** takes additional defensive steps to protect the application from harm
+** including:
+** <ul>
+** <li> Prohibit the use of SQL functions inside triggers, views,
+** CHECK constraints, DEFAULT clauses, expression indexes,
+** partial indexes, or generated columns
+** unless those functions are tagged with [SQLITE_INNOCUOUS].
+** <li> Prohibit the use of virtual tables inside of triggers or views
+** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
+** </ul>
+** This setting defaults to "on" for legacy compatibility, however
+** all applications are advised to turn it off if possible. This setting
+** can also be controlled using the [PRAGMA trusted_schema] statement.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
+** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</dt>
+** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
+** the legacy file format flag.  When activated, this flag causes all newly
+** created database file to have a schema format version number (the 4-byte
+** integer found at offset 44 into the database header) of 1.  This in turn
+** means that the resulting database file will be readable and writable by
+** any SQLite version back to 3.0.0 ([dateof:3.0.0]).  Without this setting,
+** newly created databases are generally not understandable by SQLite versions
+** prior to 3.3.0 ([dateof:3.3.0]).  As these words are written, there
+** is now scarcely any need to generate database files that are compatible
+** all the way back to version 3.0.0, and so this setting is of little
+** practical use, but is provided so that SQLite can continue to claim the
+** ability to generate new database files that are compatible with  version
+** 3.0.0.
+** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
+** the [VACUUM] command will fail with an obscure error when attempting to
+** process a table with generated columns and a descending index.  This is
+** not considered a bug since SQLite versions 3.3.0 and earlier do not support
+** either generated columns or descending indexes.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_STMT_SCANSTATUS]]
+** <dt>SQLITE_DBCONFIG_STMT_SCANSTATUS</dt>
+** <dd>The SQLITE_DBCONFIG_STMT_SCANSTATUS option is only useful in
+** SQLITE_ENABLE_STMT_SCANSTATUS builds. In this case, it sets or clears
+** a flag that enables collection of the sqlite3_stmt_scanstatus_v2()
+** statistics. For statistics to be collected, the flag must be set on
+** the database handle both when the SQL statement is prepared and when it
+** is stepped. The flag is set (collection of statistics is enabled)
+** by default. <p>This option takes two arguments: an integer and a pointer to
+** an integer..  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the statement scanstatus option.  If the second argument
+** is not NULL, then the value of the statement scanstatus setting after
+** processing the first argument is written into the integer that the second
+** argument points to.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_REVERSE_SCANORDER]]
+** <dt>SQLITE_DBCONFIG_REVERSE_SCANORDER</dt>
+** <dd>The SQLITE_DBCONFIG_REVERSE_SCANORDER option changes the default order
+** in which tables and indexes are scanned so that the scans start at the end
+** and work toward the beginning rather than starting at the beginning and
+** working toward the end. Setting SQLITE_DBCONFIG_REVERSE_SCANORDER is the
+** same as setting [PRAGMA reverse_unordered_selects]. <p>This option takes
+** two arguments which are an integer and a pointer to an integer.  The first
+** argument is 1, 0, or -1 to enable, disable, or leave unchanged the
+** reverse scan order flag, respectively.  If the second argument is not NULL,
+** then 0 or 1 is written into the integer that the second argument points to
+** depending on if the reverse scan order flag is set after processing the
+** first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]]
+** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE option enables or disables
+** the ability of the [ATTACH DATABASE] SQL command to create a new database
+** file if the database filed named in the ATTACH command does not already
+** exist.  This ability of ATTACH to create a new database is enabled by
+** default.  Applications can disable or reenable the ability for ATTACH to
+** create new database files using this DBCONFIG option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the attach-create flag, respectively.  If the second
+** argument is not NULL, then 0 or 1 is written into the integer that the
+** second argument points to depending on if the attach-create flag is set
+** after processing the first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE]]
+** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE option enables or disables the
+** ability of the [ATTACH DATABASE] SQL command to open a database for writing.
+** This capability is enabled by default.  Applications can disable or
+** reenable this capability using the current DBCONFIG option.  If the
+** the this capability is disabled, the [ATTACH] command will still work,
+** but the database will be opened read-only.  If this option is disabled,
+** then the ability to create a new database using [ATTACH] is also disabled,
+** regardless of the value of the [SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]
+** option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the ability to ATTACH another database for writing,
+** respectively.  If the second argument is not NULL, then 0 or 1 is written
+** into the integer to which the second argument points, depending on whether
+** the ability to ATTACH a read/write database is enabled or disabled
+** after processing the first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_COMMENTS]]
+** <dt>SQLITE_DBCONFIG_ENABLE_COMMENTS</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_COMMENTS option enables or disables the
+** ability to include comments in SQL text.  Comments are enabled by default.
+** An application can disable or reenable comments in SQL text using this
+** DBCONFIG option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the ability to use comments in SQL text,
+** respectively.  If the second argument is not NULL, then 0 or 1 is written
+** into the integer that the second argument points to depending on if
+** comments are allowed in SQL text after processing the first argument.
+** </dd>
+**
+** </dl>
+**
+** [[DBCONFIG arguments]] <h3>Arguments To SQLITE_DBCONFIG Options</h3>
+**
+** <p>Most of the SQLITE_DBCONFIG options take two arguments, so that the
+** overall call to [sqlite3_db_config()] has a total of four parameters.
+** The first argument (the third parameter to sqlite3_db_config()) is a integer.
+** The second argument is a pointer to an integer.  If the first argument is 1,
+** then the option becomes enabled.  If the first integer argument is 0, then the
+** option is disabled.  If the first argument is -1, then the option setting
+** is unchanged.  The second argument, the pointer to an integer, may be NULL.
+** If the second argument is not NULL, then a value of 0 or 1 is written into
+** the integer to which the second argument points, depending on whether the
+** setting is disabled or enabled after applying any changes specified by
+** the first argument.
+**
+** <p>While most SQLITE_DBCONFIG options use the argument format
+** described in the previous paragraph, the [SQLITE_DBCONFIG_MAINDBNAME]
+** and [SQLITE_DBCONFIG_LOOKASIDE] options are different.  See the
+** documentation of those exceptional options for details.
+*/
+#define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
+#define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
+#define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
+#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
+#define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
+#define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
+#define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
+#define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
+#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
+#define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
+#define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
+#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
+#define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
+#define SQLITE_DBCONFIG_STMT_SCANSTATUS       1018 /* int int* */
+#define SQLITE_DBCONFIG_REVERSE_SCANORDER     1019 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE  1020 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE   1021 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_COMMENTS       1022 /* int int* */
+#define SQLITE_DBCONFIG_MAX                   1022 /* Largest DBCONFIG */
+
+/*
+** CAPI3REF: Enable Or Disable Extended Result Codes
+** METHOD: sqlite3
+**
+** ^The sqlite3_extended_result_codes() routine enables or disables the
+** [extended result codes] feature of SQLite. ^The extended result
+** codes are disabled by default for historical compatibility.
+*/
+SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
+
+/*
+** CAPI3REF: Last Insert Rowid
+** METHOD: sqlite3
+**
+** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
+** has a unique 64-bit signed
+** integer key called the [ROWID | "rowid"]. ^The rowid is always available
+** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
+** names are not also used by explicitly declared columns. ^If
+** the table has a column of type [INTEGER PRIMARY KEY] then that column
+** is another alias for the rowid.
+**
+** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
+** the most recent successful [INSERT] into a rowid table or [virtual table]
+** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
+** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
+** on the database connection D, then sqlite3_last_insert_rowid(D) returns
+** zero.
+**
+** As well as being set automatically as rows are inserted into database
+** tables, the value returned by this function may be set explicitly by
+** [sqlite3_set_last_insert_rowid()]
+**
+** Some virtual table implementations may INSERT rows into rowid tables as
+** part of committing a transaction (e.g. to flush data accumulated in memory
+** to disk). In this case subsequent calls to this function return the rowid
+** associated with these internal INSERT operations, which leads to
+** unintuitive results. Virtual table implementations that do write to rowid
+** tables in this way can avoid this problem by restoring the original
+** rowid value using [sqlite3_set_last_insert_rowid()] before returning
+** control to the user.
+**
+** ^(If an [INSERT] occurs within a trigger then this routine will
+** return the [rowid] of the inserted row as long as the trigger is
+** running. Once the trigger program ends, the value returned
+** by this routine reverts to what it was before the trigger was fired.)^
+**
+** ^An [INSERT] that fails due to a constraint violation is not a
+** successful [INSERT] and does not change the value returned by this
+** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
+** and INSERT OR ABORT make no changes to the return value of this
+** routine when their insertion fails.  ^(When INSERT OR REPLACE
+** encounters a constraint violation, it does not fail.  The
+** INSERT continues to completion after deleting rows that caused
+** the constraint problem so INSERT OR REPLACE will always change
+** the return value of this interface.)^
+**
+** ^For the purposes of this routine, an [INSERT] is considered to
+** be successful even if it is subsequently rolled back.
+**
+** This function is accessible to SQL statements via the
+** [last_insert_rowid() SQL function].
+**
+** If a separate thread performs a new [INSERT] on the same
+** database connection while the [sqlite3_last_insert_rowid()]
+** function is running and thus changes the last insert [rowid],
+** then the value returned by [sqlite3_last_insert_rowid()] is
+** unpredictable and might not equal either the old or the new
+** last insert [rowid].
+*/
+SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
+
+/*
+** CAPI3REF: Set the Last Insert Rowid value.
+** METHOD: sqlite3
+**
+** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
+** set the value returned by calling sqlite3_last_insert_rowid(D) to R
+** without inserting a row into the database.
+*/
+SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
+
+/*
+** CAPI3REF: Count The Number Of Rows Modified
+** METHOD: sqlite3
+**
+** ^These functions return the number of rows modified, inserted or
+** deleted by the most recently completed INSERT, UPDATE or DELETE
+** statement on the database connection specified by the only parameter.
+** The two functions are identical except for the type of the return value
+** and that if the number of rows modified by the most recent INSERT, UPDATE,
+** or DELETE is greater than the maximum value supported by type "int", then
+** the return value of sqlite3_changes() is undefined. ^Executing any other
+** type of SQL statement does not modify the value returned by these functions.
+** For the purposes of this interface, a CREATE TABLE AS SELECT statement
+** does not count as an INSERT, UPDATE or DELETE statement and hence the rows
+** added to the new table by the CREATE TABLE AS SELECT statement are not
+** counted.
+**
+** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
+** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
+** [foreign key actions] or [REPLACE] constraint resolution are not counted.
+**
+** Changes to a view that are intercepted by
+** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
+** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
+** DELETE statement run on a view is always zero. Only changes made to real
+** tables are counted.
+**
+** Things are more complicated if the sqlite3_changes() function is
+** executed while a trigger program is running. This may happen if the
+** program uses the [changes() SQL function], or if some other callback
+** function invokes sqlite3_changes() directly. Essentially:
+**
+** <ul>
+**   <li> ^(Before entering a trigger program the value returned by
+**        sqlite3_changes() function is saved. After the trigger program
+**        has finished, the original value is restored.)^
+**
+**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
+**        statement sets the value returned by sqlite3_changes()
+**        upon completion as normal. Of course, this value will not include
+**        any changes performed by sub-triggers, as the sqlite3_changes()
+**        value will be saved and restored after each sub-trigger has run.)^
+** </ul>
+**
+** ^This means that if the changes() SQL function (or similar) is used
+** by the first INSERT, UPDATE or DELETE statement within a trigger, it
+** returns the value as set when the calling statement began executing.
+** ^If it is used by the second or subsequent such statement within a trigger
+** program, the value returned reflects the number of rows modified by the
+** previous INSERT, UPDATE or DELETE statement within the same trigger.
+**
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_changes()] is running then the value returned
+** is unpredictable and not meaningful.
+**
+** See also:
+** <ul>
+** <li> the [sqlite3_total_changes()] interface
+** <li> the [count_changes pragma]
+** <li> the [changes() SQL function]
+** <li> the [data_version pragma]
+** </ul>
+*/
+SQLITE_API int sqlite3_changes(sqlite3*);
+SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3*);
+
+/*
+** CAPI3REF: Total Number Of Rows Modified
+** METHOD: sqlite3
+**
+** ^These functions return the total number of rows inserted, modified or
+** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
+** since the database connection was opened, including those executed as
+** part of trigger programs. The two functions are identical except for the
+** type of the return value and that if the number of rows modified by the
+** connection exceeds the maximum value supported by type "int", then
+** the return value of sqlite3_total_changes() is undefined. ^Executing
+** any other type of SQL statement does not affect the value returned by
+** sqlite3_total_changes().
+**
+** ^Changes made as part of [foreign key actions] are included in the
+** count, but those made as part of REPLACE constraint resolution are
+** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
+** are not counted.
+**
+** The [sqlite3_total_changes(D)] interface only reports the number
+** of rows that changed due to SQL statement run against database
+** connection D.  Any changes by other database connections are ignored.
+** To detect changes against a database file from other database
+** connections use the [PRAGMA data_version] command or the
+** [SQLITE_FCNTL_DATA_VERSION] [file control].
+**
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_total_changes()] is running then the value
+** returned is unpredictable and not meaningful.
+**
+** See also:
+** <ul>
+** <li> the [sqlite3_changes()] interface
+** <li> the [count_changes pragma]
+** <li> the [changes() SQL function]
+** <li> the [data_version pragma]
+** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
+** </ul>
+*/
+SQLITE_API int sqlite3_total_changes(sqlite3*);
+SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3*);
+
+/*
+** CAPI3REF: Interrupt A Long-Running Query
+** METHOD: sqlite3
+**
+** ^This function causes any pending database operation to abort and
+** return at its earliest opportunity. This routine is typically
+** called in response to a user action such as pressing "Cancel"
+** or Ctrl-C where the user wants a long query operation to halt
+** immediately.
+**
+** ^It is safe to call this routine from a thread different from the
+** thread that is currently running the database operation.  But it
+** is not safe to call this routine with a [database connection] that
+** is closed or might close before sqlite3_interrupt() returns.
+**
+** ^If an SQL operation is very nearly finished at the time when
+** sqlite3_interrupt() is called, then it might not have an opportunity
+** to be interrupted and might continue to completion.
+**
+** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
+** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
+** that is inside an explicit transaction, then the entire transaction
+** will be rolled back automatically.
+**
+** ^The sqlite3_interrupt(D) call is in effect until all currently running
+** SQL statements on [database connection] D complete.  ^Any new SQL statements
+** that are started after the sqlite3_interrupt() call and before the
+** running statement count reaches zero are interrupted as if they had been
+** running prior to the sqlite3_interrupt() call.  ^New SQL statements
+** that are started after the running statement count reaches zero are
+** not effected by the sqlite3_interrupt().
+** ^A call to sqlite3_interrupt(D) that occurs when there are no running
+** SQL statements is a no-op and has no effect on SQL statements
+** that are started after the sqlite3_interrupt() call returns.
+**
+** ^The [sqlite3_is_interrupted(D)] interface can be used to determine whether
+** or not an interrupt is currently in effect for [database connection] D.
+** It returns 1 if an interrupt is currently in effect, or 0 otherwise.
+*/
+SQLITE_API void sqlite3_interrupt(sqlite3*);
+SQLITE_API int sqlite3_is_interrupted(sqlite3*);
+
+/*
+** CAPI3REF: Determine If An SQL Statement Is Complete
+**
+** These routines are useful during command-line input to determine if the
+** currently entered text seems to form a complete SQL statement or
+** if additional input is needed before sending the text into
+** SQLite for parsing.  ^These routines return 1 if the input string
+** appears to be a complete SQL statement.  ^A statement is judged to be
+** complete if it ends with a semicolon token and is not a prefix of a
+** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
+** string literals or quoted identifier names or comments are not
+** independent tokens (they are part of the token in which they are
+** embedded) and thus do not count as a statement terminator.  ^Whitespace
+** and comments that follow the final semicolon are ignored.
+**
+** ^These routines return 0 if the statement is incomplete.  ^If a
+** memory allocation fails, then SQLITE_NOMEM is returned.
+**
+** ^These routines do not parse the SQL statements thus
+** will not detect syntactically incorrect SQL.
+**
+** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
+** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
+** automatically by sqlite3_complete16().  If that initialization fails,
+** then the return value from sqlite3_complete16() will be non-zero
+** regardless of whether or not the input SQL is complete.)^
+**
+** The input to [sqlite3_complete()] must be a zero-terminated
+** UTF-8 string.
+**
+** The input to [sqlite3_complete16()] must be a zero-terminated
+** UTF-16 string in native byte order.
+*/
+SQLITE_API int sqlite3_complete(const char *sql);
+SQLITE_API int sqlite3_complete16(const void *sql);
+
+/*
+** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
+** KEYWORDS: {busy-handler callback} {busy handler}
+** METHOD: sqlite3
+**
+** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
+** that might be invoked with argument P whenever
+** an attempt is made to access a database table associated with
+** [database connection] D when another thread
+** or process has the table locked.
+** The sqlite3_busy_handler() interface is used to implement
+** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
+**
+** ^If the busy callback is NULL, then [SQLITE_BUSY]
+** is returned immediately upon encountering the lock.  ^If the busy callback
+** is not NULL, then the callback might be invoked with two arguments.
+**
+** ^The first argument to the busy handler is a copy of the void* pointer which
+** is the third argument to sqlite3_busy_handler().  ^The second argument to
+** the busy handler callback is the number of times that the busy handler has
+** been invoked previously for the same locking event.  ^If the
+** busy callback returns 0, then no additional attempts are made to
+** access the database and [SQLITE_BUSY] is returned
+** to the application.
+** ^If the callback returns non-zero, then another attempt
+** is made to access the database and the cycle repeats.
+**
+** The presence of a busy handler does not guarantee that it will be invoked
+** when there is lock contention. ^If SQLite determines that invoking the busy
+** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
+** to the application instead of invoking the
+** busy handler.
+** Consider a scenario where one process is holding a read lock that
+** it is trying to promote to a reserved lock and
+** a second process is holding a reserved lock that it is trying
+** to promote to an exclusive lock.  The first process cannot proceed
+** because it is blocked by the second and the second process cannot
+** proceed because it is blocked by the first.  If both processes
+** invoke the busy handlers, neither will make any progress.  Therefore,
+** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
+** will induce the first process to release its read lock and allow
+** the second process to proceed.
+**
+** ^The default busy callback is NULL.
+**
+** ^(There can only be a single busy handler defined for each
+** [database connection].  Setting a new busy handler clears any
+** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
+** or evaluating [PRAGMA busy_timeout=N] will change the
+** busy handler and thus clear any previously set busy handler.
+**
+** The busy callback should not take any actions which modify the
+** database connection that invoked the busy handler.  In other words,
+** the busy handler is not reentrant.  Any such actions
+** result in undefined behavior.
+**
+** A busy handler must not close the database connection
+** or [prepared statement] that invoked the busy handler.
+*/
+SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
+
+/*
+** CAPI3REF: Set A Busy Timeout
+** METHOD: sqlite3
+**
+** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
+** for a specified amount of time when a table is locked.  ^The handler
+** will sleep multiple times until at least "ms" milliseconds of sleeping
+** have accumulated.  ^After at least "ms" milliseconds of sleeping,
+** the handler returns 0 which causes [sqlite3_step()] to return
+** [SQLITE_BUSY].
+**
+** ^Calling this routine with an argument less than or equal to zero
+** turns off all busy handlers.
+**
+** ^(There can only be a single busy handler for a particular
+** [database connection] at any given moment.  If another busy handler
+** was defined  (using [sqlite3_busy_handler()]) prior to calling
+** this routine, that other busy handler is cleared.)^
+**
+** See also:  [PRAGMA busy_timeout]
+*/
+SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
+
+/*
+** CAPI3REF: Convenience Routines For Running Queries
+** METHOD: sqlite3
+**
+** This is a legacy interface that is preserved for backwards compatibility.
+** Use of this interface is not recommended.
+**
+** Definition: A <b>result table</b> is memory data structure created by the
+** [sqlite3_get_table()] interface.  A result table records the
+** complete query results from one or more queries.
+**
+** The table conceptually has a number of rows and columns.  But
+** these numbers are not part of the result table itself.  These
+** numbers are obtained separately.  Let N be the number of rows
+** and M be the number of columns.
+**
+** A result table is an array of pointers to zero-terminated UTF-8 strings.
+** There are (N+1)*M elements in the array.  The first M pointers point
+** to zero-terminated strings that  contain the names of the columns.
+** The remaining entries all point to query results.  NULL values result
+** in NULL pointers.  All other values are in their UTF-8 zero-terminated
+** string representation as returned by [sqlite3_column_text()].
+**
+** A result table might consist of one or more memory allocations.
+** It is not safe to pass a result table directly to [sqlite3_free()].
+** A result table should be deallocated using [sqlite3_free_table()].
+**
+** ^(As an example of the result table format, suppose a query result
+** is as follows:
+**
+** <blockquote><pre>
+**        Name        | Age
+**        -----------------------
+**        Alice       | 43
+**        Bob         | 28
+**        Cindy       | 21
+** </pre></blockquote>
+**
+** There are two columns (M==2) and three rows (N==3).  Thus the
+** result table has 8 entries.  Suppose the result table is stored
+** in an array named azResult.  Then azResult holds this content:
+**
+** <blockquote><pre>
+**        azResult[0] = "Name";
+**        azResult[1] = "Age";
+**        azResult[2] = "Alice";
+**        azResult[3] = "43";
+**        azResult[4] = "Bob";
+**        azResult[5] = "28";
+**        azResult[6] = "Cindy";
+**        azResult[7] = "21";
+** </pre></blockquote>)^
+**
+** ^The sqlite3_get_table() function evaluates one or more
+** semicolon-separated SQL statements in the zero-terminated UTF-8
+** string of its 2nd parameter and returns a result table to the
+** pointer given in its 3rd parameter.
+**
+** After the application has finished with the result from sqlite3_get_table(),
+** it must pass the result table pointer to sqlite3_free_table() in order to
+** release the memory that was malloced.  Because of the way the
+** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
+** function must not try to call [sqlite3_free()] directly.  Only
+** [sqlite3_free_table()] is able to release the memory properly and safely.
+**
+** The sqlite3_get_table() interface is implemented as a wrapper around
+** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
+** to any internal data structures of SQLite.  It uses only the public
+** interface defined here.  As a consequence, errors that occur in the
+** wrapper layer outside of the internal [sqlite3_exec()] call are not
+** reflected in subsequent calls to [sqlite3_errcode()] or
+** [sqlite3_errmsg()].
+*/
+SQLITE_API int sqlite3_get_table(
+  sqlite3 *db,          /* An open database */
+  const char *zSql,     /* SQL to be evaluated */
+  char ***pazResult,    /* Results of the query */
+  int *pnRow,           /* Number of result rows written here */
+  int *pnColumn,        /* Number of result columns written here */
+  char **pzErrmsg       /* Error msg written here */
+);
+SQLITE_API void sqlite3_free_table(char **result);
+
+/*
+** CAPI3REF: Formatted String Printing Functions
+**
+** These routines are work-alikes of the "printf()" family of functions
+** from the standard C library.
+** These routines understand most of the common formatting options from
+** the standard library printf()
+** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
+** See the [built-in printf()] documentation for details.
+**
+** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
+** results into memory obtained from [sqlite3_malloc64()].
+** The strings returned by these two routines should be
+** released by [sqlite3_free()].  ^Both routines return a
+** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
+** memory to hold the resulting string.
+**
+** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
+** the standard C library.  The result is written into the
+** buffer supplied as the second parameter whose size is given by
+** the first parameter. Note that the order of the
+** first two parameters is reversed from snprintf().)^  This is an
+** historical accident that cannot be fixed without breaking
+** backwards compatibility.  ^(Note also that sqlite3_snprintf()
+** returns a pointer to its buffer instead of the number of
+** characters actually written into the buffer.)^  We admit that
+** the number of characters written would be a more useful return
+** value but we cannot change the implementation of sqlite3_snprintf()
+** now without breaking compatibility.
+**
+** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
+** guarantees that the buffer is always zero-terminated.  ^The first
+** parameter "n" is the total size of the buffer, including space for
+** the zero terminator.  So the longest string that can be completely
+** written will be n-1 characters.
+**
+** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
+**
+** See also:  [built-in printf()], [printf() SQL function]
+*/
+SQLITE_API char *sqlite3_mprintf(const char*,...);
+SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
+SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
+SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
+
+/*
+** CAPI3REF: Memory Allocation Subsystem
+**
+** The SQLite core uses these three routines for all of its own
+** internal memory allocation needs. "Core" in the previous sentence
+** does not include operating-system specific [VFS] implementation.  The
+** Windows VFS uses native malloc() and free() for some operations.
+**
+** ^The sqlite3_malloc() routine returns a pointer to a block
+** of memory at least N bytes in length, where N is the parameter.
+** ^If sqlite3_malloc() is unable to obtain sufficient free
+** memory, it returns a NULL pointer.  ^If the parameter N to
+** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
+** a NULL pointer.
+**
+** ^The sqlite3_malloc64(N) routine works just like
+** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
+** of a signed 32-bit integer.
+**
+** ^Calling sqlite3_free() with a pointer previously returned
+** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
+** that it might be reused.  ^The sqlite3_free() routine is
+** a no-op if is called with a NULL pointer.  Passing a NULL pointer
+** to sqlite3_free() is harmless.  After being freed, memory
+** should neither be read nor written.  Even reading previously freed
+** memory might result in a segmentation fault or other severe error.
+** Memory corruption, a segmentation fault, or other severe error
+** might result if sqlite3_free() is called with a non-NULL pointer that
+** was not obtained from sqlite3_malloc() or sqlite3_realloc().
+**
+** ^The sqlite3_realloc(X,N) interface attempts to resize a
+** prior memory allocation X to be at least N bytes.
+** ^If the X parameter to sqlite3_realloc(X,N)
+** is a NULL pointer then its behavior is identical to calling
+** sqlite3_malloc(N).
+** ^If the N parameter to sqlite3_realloc(X,N) is zero or
+** negative then the behavior is exactly the same as calling
+** sqlite3_free(X).
+** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
+** of at least N bytes in size or NULL if insufficient memory is available.
+** ^If M is the size of the prior allocation, then min(N,M) bytes
+** of the prior allocation are copied into the beginning of buffer returned
+** by sqlite3_realloc(X,N) and the prior allocation is freed.
+** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
+** prior allocation is not freed.
+**
+** ^The sqlite3_realloc64(X,N) interfaces works the same as
+** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
+** of a 32-bit signed integer.
+**
+** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
+** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
+** sqlite3_msize(X) returns the size of that memory allocation in bytes.
+** ^The value returned by sqlite3_msize(X) might be larger than the number
+** of bytes requested when X was allocated.  ^If X is a NULL pointer then
+** sqlite3_msize(X) returns zero.  If X points to something that is not
+** the beginning of memory allocation, or if it points to a formerly
+** valid memory allocation that has now been freed, then the behavior
+** of sqlite3_msize(X) is undefined and possibly harmful.
+**
+** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
+** sqlite3_malloc64(), and sqlite3_realloc64()
+** is always aligned to at least an 8 byte boundary, or to a
+** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
+** option is used.
+**
+** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
+** must be either NULL or else pointers obtained from a prior
+** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
+** not yet been released.
+**
+** The application must not read or write any part of
+** a block of memory after it has been released using
+** [sqlite3_free()] or [sqlite3_realloc()].
+*/
+SQLITE_API void *sqlite3_malloc(int);
+SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
+SQLITE_API void *sqlite3_realloc(void*, int);
+SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
+SQLITE_API void sqlite3_free(void*);
+SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
+
+/*
+** CAPI3REF: Memory Allocator Statistics
+**
+** SQLite provides these two interfaces for reporting on the status
+** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
+** routines, which form the built-in memory allocation subsystem.
+**
+** ^The [sqlite3_memory_used()] routine returns the number of bytes
+** of memory currently outstanding (malloced but not freed).
+** ^The [sqlite3_memory_highwater()] routine returns the maximum
+** value of [sqlite3_memory_used()] since the high-water mark
+** was last reset.  ^The values returned by [sqlite3_memory_used()] and
+** [sqlite3_memory_highwater()] include any overhead
+** added by SQLite in its implementation of [sqlite3_malloc()],
+** but not overhead added by the any underlying system library
+** routines that [sqlite3_malloc()] may call.
+**
+** ^The memory high-water mark is reset to the current value of
+** [sqlite3_memory_used()] if and only if the parameter to
+** [sqlite3_memory_highwater()] is true.  ^The value returned
+** by [sqlite3_memory_highwater(1)] is the high-water mark
+** prior to the reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
+
+/*
+** CAPI3REF: Pseudo-Random Number Generator
+**
+** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
+** select random [ROWID | ROWIDs] when inserting new records into a table that
+** already uses the largest possible [ROWID].  The PRNG is also used for
+** the built-in random() and randomblob() SQL functions.  This interface allows
+** applications to access the same PRNG for other purposes.
+**
+** ^A call to this routine stores N bytes of randomness into buffer P.
+** ^The P parameter can be a NULL pointer.
+**
+** ^If this routine has not been previously called or if the previous
+** call had N less than one or a NULL pointer for P, then the PRNG is
+** seeded using randomness obtained from the xRandomness method of
+** the default [sqlite3_vfs] object.
+** ^If the previous call to this routine had an N of 1 or more and a
+** non-NULL P then the pseudo-randomness is generated
+** internally and without recourse to the [sqlite3_vfs] xRandomness
+** method.
+*/
+SQLITE_API void sqlite3_randomness(int N, void *P);
+
+/*
+** CAPI3REF: Compile-Time Authorization Callbacks
+** METHOD: sqlite3
+** KEYWORDS: {authorizer callback}
+**
+** ^This routine registers an authorizer callback with a particular
+** [database connection], supplied in the first argument.
+** ^The authorizer callback is invoked as SQL statements are being compiled
+** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
+** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
+** and [sqlite3_prepare16_v3()].  ^At various
+** points during the compilation process, as logic is being created
+** to perform various actions, the authorizer callback is invoked to
+** see if those actions are allowed.  ^The authorizer callback should
+** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
+** specific action but allow the SQL statement to continue to be
+** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
+** rejected with an error.  ^If the authorizer callback returns
+** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
+** then the [sqlite3_prepare_v2()] or equivalent call that triggered
+** the authorizer will fail with an error message.
+**
+** When the callback returns [SQLITE_OK], that means the operation
+** requested is ok.  ^When the callback returns [SQLITE_DENY], the
+** [sqlite3_prepare_v2()] or equivalent call that triggered the
+** authorizer will fail with an error message explaining that
+** access is denied.
+**
+** ^The first parameter to the authorizer callback is a copy of the third
+** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
+** to the callback is an integer [SQLITE_COPY | action code] that specifies
+** the particular action to be authorized. ^The third through sixth parameters
+** to the callback are either NULL pointers or zero-terminated strings
+** that contain additional details about the action to be authorized.
+** Applications must always be prepared to encounter a NULL pointer in any
+** of the third through the sixth parameters of the authorization callback.
+**
+** ^If the action code is [SQLITE_READ]
+** and the callback returns [SQLITE_IGNORE] then the
+** [prepared statement] statement is constructed to substitute
+** a NULL value in place of the table column that would have
+** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
+** return can be used to deny an untrusted user access to individual
+** columns of a table.
+** ^When a table is referenced by a [SELECT] but no column values are
+** extracted from that table (for example in a query like
+** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
+** is invoked once for that table with a column name that is an empty string.
+** ^If the action code is [SQLITE_DELETE] and the callback returns
+** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
+** [truncate optimization] is disabled and all rows are deleted individually.
+**
+** An authorizer is used when [sqlite3_prepare | preparing]
+** SQL statements from an untrusted source, to ensure that the SQL statements
+** do not try to access data they are not allowed to see, or that they do not
+** try to execute malicious statements that damage the database.  For
+** example, an application may allow a user to enter arbitrary
+** SQL queries for evaluation by a database.  But the application does
+** not want the user to be able to make arbitrary changes to the
+** database.  An authorizer could then be put in place while the
+** user-entered SQL is being [sqlite3_prepare | prepared] that
+** disallows everything except [SELECT] statements.
+**
+** Applications that need to process SQL from untrusted sources
+** might also consider lowering resource limits using [sqlite3_limit()]
+** and limiting database size using the [max_page_count] [PRAGMA]
+** in addition to using an authorizer.
+**
+** ^(Only a single authorizer can be in place on a database connection
+** at a time.  Each call to sqlite3_set_authorizer overrides the
+** previous call.)^  ^Disable the authorizer by installing a NULL callback.
+** The authorizer is disabled by default.
+**
+** The authorizer callback must not do anything that will modify
+** the database connection that invoked the authorizer callback.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
+** statement might be re-prepared during [sqlite3_step()] due to a
+** schema change.  Hence, the application should ensure that the
+** correct authorizer callback remains in place during the [sqlite3_step()].
+**
+** ^Note that the authorizer callback is invoked only during
+** [sqlite3_prepare()] or its variants.  Authorization is not
+** performed during statement evaluation in [sqlite3_step()], unless
+** as stated in the previous paragraph, sqlite3_step() invokes
+** sqlite3_prepare_v2() to reprepare a statement after a schema change.
+*/
+SQLITE_API int sqlite3_set_authorizer(
+  sqlite3*,
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
+  void *pUserData
+);
+
+/*
+** CAPI3REF: Authorizer Return Codes
+**
+** The [sqlite3_set_authorizer | authorizer callback function] must
+** return either [SQLITE_OK] or one of these two constants in order
+** to signal SQLite whether or not the action is permitted.  See the
+** [sqlite3_set_authorizer | authorizer documentation] for additional
+** information.
+**
+** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
+** returned from the [sqlite3_vtab_on_conflict()] interface.
+*/
+#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
+#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
+
+/*
+** CAPI3REF: Authorizer Action Codes
+**
+** The [sqlite3_set_authorizer()] interface registers a callback function
+** that is invoked to authorize certain SQL statement actions.  The
+** second parameter to the callback is an integer code that specifies
+** what action is being authorized.  These are the integer action codes that
+** the authorizer callback may be passed.
+**
+** These action code values signify what kind of operation is to be
+** authorized.  The 3rd and 4th parameters to the authorization
+** callback function will be parameters or NULL depending on which of these
+** codes is used as the second parameter.  ^(The 5th parameter to the
+** authorizer callback is the name of the database ("main", "temp",
+** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
+** is the name of the inner-most trigger or view that is responsible for
+** the access attempt or NULL if this access attempt is directly from
+** top-level SQL code.
+*/
+/******************************************* 3rd ************ 4th ***********/
+#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
+#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
+#define SQLITE_DELETE                9   /* Table Name      NULL            */
+#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
+#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
+#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
+#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
+#define SQLITE_INSERT               18   /* Table Name      NULL            */
+#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
+#define SQLITE_READ                 20   /* Table Name      Column Name     */
+#define SQLITE_SELECT               21   /* NULL            NULL            */
+#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
+#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
+#define SQLITE_ATTACH               24   /* Filename        NULL            */
+#define SQLITE_DETACH               25   /* Database Name   NULL            */
+#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
+#define SQLITE_REINDEX              27   /* Index Name      NULL            */
+#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
+#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
+#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
+#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
+#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
+#define SQLITE_COPY                  0   /* No longer used */
+#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
+
+/*
+** CAPI3REF: Deprecated Tracing And Profiling Functions
+** DEPRECATED
+**
+** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
+** instead of the routines described here.
+**
+** These routines register callback functions that can be used for
+** tracing and profiling the execution of SQL statements.
+**
+** ^The callback function registered by sqlite3_trace() is invoked at
+** various times when an SQL statement is being run by [sqlite3_step()].
+** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
+** SQL statement text as the statement first begins executing.
+** ^(Additional sqlite3_trace() callbacks might occur
+** as each triggered subprogram is entered.  The callbacks for triggers
+** contain a UTF-8 SQL comment that identifies the trigger.)^
+**
+** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
+** the length of [bound parameter] expansion in the output of sqlite3_trace().
+**
+** ^The callback function registered by sqlite3_profile() is invoked
+** as each SQL statement finishes.  ^The profile callback contains
+** the original statement text and an estimate of wall-clock time
+** of how long that statement took to run.  ^The profile callback
+** time is in units of nanoseconds, however the current implementation
+** is only capable of millisecond resolution so the six least significant
+** digits in the time are meaningless.  Future versions of SQLite
+** might provide greater resolution on the profiler callback.  Invoking
+** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
+** profile callback.
+*/
+SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
+   void(*xTrace)(void*,const char*), void*);
+SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
+   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
+
+/*
+** CAPI3REF: SQL Trace Event Codes
+** KEYWORDS: SQLITE_TRACE
+**
+** These constants identify classes of events that can be monitored
+** using the [sqlite3_trace_v2()] tracing logic.  The M argument
+** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
+** the following constants.  ^The first argument to the trace callback
+** is one of the following constants.
+**
+** New tracing constants may be added in future releases.
+**
+** ^A trace callback has four arguments: xCallback(T,C,P,X).
+** ^The T argument is one of the integer type codes above.
+** ^The C argument is a copy of the context pointer passed in as the
+** fourth argument to [sqlite3_trace_v2()].
+** The P and X arguments are pointers whose meanings depend on T.
+**
+** <dl>
+** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
+** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
+** first begins running and possibly at other times during the
+** execution of the prepared statement, such as at the start of each
+** trigger subprogram. ^The P argument is a pointer to the
+** [prepared statement]. ^The X argument is a pointer to a string which
+** is the unexpanded SQL text of the prepared statement or an SQL comment
+** that indicates the invocation of a trigger.  ^The callback can compute
+** the same text that would have been returned by the legacy [sqlite3_trace()]
+** interface by using the X argument when X begins with "--" and invoking
+** [sqlite3_expanded_sql(P)] otherwise.
+**
+** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
+** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
+** information as is provided by the [sqlite3_profile()] callback.
+** ^The P argument is a pointer to the [prepared statement] and the
+** X argument points to a 64-bit integer which is approximately
+** the number of nanoseconds that the prepared statement took to run.
+** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
+**
+** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
+** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
+** statement generates a single row of result.
+** ^The P argument is a pointer to the [prepared statement] and the
+** X argument is unused.
+**
+** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
+** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
+** connection closes.
+** ^The P argument is a pointer to the [database connection] object
+** and the X argument is unused.
+** </dl>
+*/
+#define SQLITE_TRACE_STMT       0x01
+#define SQLITE_TRACE_PROFILE    0x02
+#define SQLITE_TRACE_ROW        0x04
+#define SQLITE_TRACE_CLOSE      0x08
+
+/*
+** CAPI3REF: SQL Trace Hook
+** METHOD: sqlite3
+**
+** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
+** function X against [database connection] D, using property mask M
+** and context pointer P.  ^If the X callback is
+** NULL or if the M mask is zero, then tracing is disabled.  The
+** M argument should be the bitwise OR-ed combination of
+** zero or more [SQLITE_TRACE] constants.
+**
+** ^Each call to either sqlite3_trace(D,X,P) or sqlite3_trace_v2(D,M,X,P)
+** overrides (cancels) all prior calls to sqlite3_trace(D,X,P) or
+** sqlite3_trace_v2(D,M,X,P) for the [database connection] D.  Each
+** database connection may have at most one trace callback.
+**
+** ^The X callback is invoked whenever any of the events identified by
+** mask M occur.  ^The integer return value from the callback is currently
+** ignored, though this may change in future releases.  Callback
+** implementations should return zero to ensure future compatibility.
+**
+** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
+** ^The T argument is one of the [SQLITE_TRACE]
+** constants to indicate why the callback was invoked.
+** ^The C argument is a copy of the context pointer.
+** The P and X arguments are pointers whose meanings depend on T.
+**
+** The sqlite3_trace_v2() interface is intended to replace the legacy
+** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
+** are deprecated.
+*/
+SQLITE_API int sqlite3_trace_v2(
+  sqlite3*,
+  unsigned uMask,
+  int(*xCallback)(unsigned,void*,void*,void*),
+  void *pCtx
+);
+
+/*
+** CAPI3REF: Query Progress Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
+** function X to be invoked periodically during long running calls to
+** [sqlite3_step()] and [sqlite3_prepare()] and similar for
+** database connection D.  An example use for this
+** interface is to keep a GUI updated during a large query.
+**
+** ^The parameter P is passed through as the only parameter to the
+** callback function X.  ^The parameter N is the approximate number of
+** [virtual machine instructions] that are evaluated between successive
+** invocations of the callback X.  ^If N is less than one then the progress
+** handler is disabled.
+**
+** ^Only a single progress handler may be defined at one time per
+** [database connection]; setting a new progress handler cancels the
+** old one.  ^Setting parameter X to NULL disables the progress handler.
+** ^The progress handler is also disabled by setting N to a value less
+** than 1.
+**
+** ^If the progress callback returns non-zero, the operation is
+** interrupted.  This feature can be used to implement a
+** "Cancel" button on a GUI progress dialog box.
+**
+** The progress handler callback must not do anything that will modify
+** the database connection that invoked the progress handler.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** The progress handler callback would originally only be invoked from the
+** bytecode engine.  It still might be invoked during [sqlite3_prepare()]
+** and similar because those routines might force a reparse of the schema
+** which involves running the bytecode engine.  However, beginning with
+** SQLite version 3.41.0, the progress handler callback might also be
+** invoked directly from [sqlite3_prepare()] while analyzing and generating
+** code for complex queries.
+*/
+SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
+
+/*
+** CAPI3REF: Opening A New Database Connection
+** CONSTRUCTOR: sqlite3
+**
+** ^These routines open an SQLite database file as specified by the
+** filename argument. ^The filename argument is interpreted as UTF-8 for
+** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
+** order for sqlite3_open16(). ^(A [database connection] handle is usually
+** returned in *ppDb, even if an error occurs.  The only exception is that
+** if SQLite is unable to allocate memory to hold the [sqlite3] object,
+** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
+** object.)^ ^(If the database is opened (and/or created) successfully, then
+** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
+** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
+** an English language description of the error following a failure of any
+** of the sqlite3_open() routines.
+**
+** ^The default encoding will be UTF-8 for databases created using
+** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
+** created using sqlite3_open16() will be UTF-16 in the native byte order.
+**
+** Whether or not an error occurs when it is opened, resources
+** associated with the [database connection] handle should be released by
+** passing it to [sqlite3_close()] when it is no longer required.
+**
+** The sqlite3_open_v2() interface works like sqlite3_open()
+** except that it accepts two additional parameters for additional control
+** over the new database connection.  ^(The flags parameter to
+** sqlite3_open_v2() must include, at a minimum, one of the following
+** three flag combinations:)^
+**
+** <dl>
+** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
+** <dd>The database is opened in read-only mode.  If the database does
+** not already exist, an error is returned.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
+** <dd>The database is opened for reading and writing if possible, or
+** reading only if the file is write protected by the operating
+** system.  In either case the database must already exist, otherwise
+** an error is returned.  For historical reasons, if opening in
+** read-write mode fails due to OS-level permissions, an attempt is
+** made to open it in read-only mode. [sqlite3_db_readonly()] can be
+** used to determine whether the database is actually
+** read-write.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
+** <dd>The database is opened for reading and writing, and is created if
+** it does not already exist. This is the behavior that is always used for
+** sqlite3_open() and sqlite3_open16().</dd>)^
+** </dl>
+**
+** In addition to the required flags, the following optional flags are
+** also supported:
+**
+** <dl>
+** ^(<dt>[SQLITE_OPEN_URI]</dt>
+** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
+** <dd>The database will be opened as an in-memory database.  The database
+** is named by the "filename" argument for the purposes of cache-sharing,
+** if shared cache mode is enabled, but the "filename" is otherwise ignored.
+** </dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
+** <dd>The new database connection will use the "multi-thread"
+** [threading mode].)^  This means that separate threads are allowed
+** to use SQLite at the same time, as long as each thread is using
+** a different [database connection].
+**
+** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
+** <dd>The new database connection will use the "serialized"
+** [threading mode].)^  This means the multiple threads can safely
+** attempt to use the same database connection at the same time.
+** (Mutexes will block any actual concurrency, but in this mode
+** there is no harm in trying.)
+**
+** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
+** <dd>The database is opened [shared cache] enabled, overriding
+** the default shared cache setting provided by
+** [sqlite3_enable_shared_cache()].)^
+** The [use of shared cache mode is discouraged] and hence shared cache
+** capabilities may be omitted from many builds of SQLite.  In such cases,
+** this option is a no-op.
+**
+** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
+** <dd>The database is opened [shared cache] disabled, overriding
+** the default shared cache setting provided by
+** [sqlite3_enable_shared_cache()].)^
+**
+** [[OPEN_EXRESCODE]] ^(<dt>[SQLITE_OPEN_EXRESCODE]</dt>
+** <dd>The database connection comes up in "extended result code mode".
+** In other words, the database behaves as if
+** [sqlite3_extended_result_codes(db,1)] were called on the database
+** connection as soon as the connection is created. In addition to setting
+** the extended result code mode, this flag also causes [sqlite3_open_v2()]
+** to return an extended result code.</dd>
+**
+** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
+** <dd>The database filename is not allowed to contain a symbolic link</dd>
+** </dl>)^
+**
+** If the 3rd parameter to sqlite3_open_v2() is not one of the
+** required combinations shown above optionally combined with other
+** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
+** then the behavior is undefined.  Historic versions of SQLite
+** have silently ignored surplus bits in the flags parameter to
+** sqlite3_open_v2(), however that behavior might not be carried through
+** into future versions of SQLite and so applications should not rely
+** upon it.  Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
+** for sqlite3_open_v2().  The SQLITE_OPEN_EXCLUSIVE does *not* cause
+** the open to fail if the database already exists.  The SQLITE_OPEN_EXCLUSIVE
+** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
+** by sqlite3_open_v2().
+**
+** ^The fourth parameter to sqlite3_open_v2() is the name of the
+** [sqlite3_vfs] object that defines the operating system interface that
+** the new database connection should use.  ^If the fourth parameter is
+** a NULL pointer then the default [sqlite3_vfs] object is used.
+**
+** ^If the filename is ":memory:", then a private, temporary in-memory database
+** is created for the connection.  ^This in-memory database will vanish when
+** the database connection is closed.  Future versions of SQLite might
+** make use of additional special filenames that begin with the ":" character.
+** It is recommended that when a database filename actually does begin with
+** a ":" character you should prefix the filename with a pathname such as
+** "./" to avoid ambiguity.
+**
+** ^If the filename is an empty string, then a private, temporary
+** on-disk database will be created.  ^This private database will be
+** automatically deleted as soon as the database connection is closed.
+**
+** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
+**
+** ^If [URI filename] interpretation is enabled, and the filename argument
+** begins with "file:", then the filename is interpreted as a URI. ^URI
+** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
+** set in the third argument to sqlite3_open_v2(), or if it has
+** been enabled globally using the [SQLITE_CONFIG_URI] option with the
+** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
+** URI filename interpretation is turned off
+** by default, but future releases of SQLite might enable URI filename
+** interpretation by default.  See "[URI filenames]" for additional
+** information.
+**
+** URI filenames are parsed according to RFC 3986. ^If the URI contains an
+** authority, then it must be either an empty string or the string
+** "localhost". ^If the authority is not an empty string or "localhost", an
+** error is returned to the caller. ^The fragment component of a URI, if
+** present, is ignored.
+**
+** ^SQLite uses the path component of the URI as the name of the disk file
+** which contains the database. ^If the path begins with a '/' character,
+** then it is interpreted as an absolute path. ^If the path does not begin
+** with a '/' (meaning that the authority section is omitted from the URI)
+** then the path is interpreted as a relative path.
+** ^(On windows, the first component of an absolute path
+** is a drive specification (e.g. "C:").)^
+**
+** [[core URI query parameters]]
+** The query component of a URI may contain parameters that are interpreted
+** either by SQLite itself, or by a [VFS | custom VFS implementation].
+** SQLite and its built-in [VFSes] interpret the
+** following query parameters:
+**
+** <ul>
+**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
+**     a VFS object that provides the operating system interface that should
+**     be used to access the database file on disk. ^If this option is set to
+**     an empty string the default VFS object is used. ^Specifying an unknown
+**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
+**     present, then the VFS specified by the option takes precedence over
+**     the value passed as the fourth parameter to sqlite3_open_v2().
+**
+**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
+**     "rwc", or "memory". Attempting to set it to any other value is
+**     an error)^.
+**     ^If "ro" is specified, then the database is opened for read-only
+**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
+**     third argument to sqlite3_open_v2(). ^If the mode option is set to
+**     "rw", then the database is opened for read-write (but not create)
+**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
+**     been set. ^Value "rwc" is equivalent to setting both
+**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
+**     set to "memory" then a pure [in-memory database] that never reads
+**     or writes from disk is used. ^It is an error to specify a value for
+**     the mode parameter that is less restrictive than that specified by
+**     the flags passed in the third parameter to sqlite3_open_v2().
+**
+**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
+**     "private". ^Setting it to "shared" is equivalent to setting the
+**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
+**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
+**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
+**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
+**     a URI filename, its value overrides any behavior requested by setting
+**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
+**
+**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
+**     [powersafe overwrite] property does or does not apply to the
+**     storage media on which the database file resides.
+**
+**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
+**     which if set disables file locking in rollback journal modes.  This
+**     is useful for accessing a database on a filesystem that does not
+**     support locking.  Caution:  Database corruption might result if two
+**     or more processes write to the same database and any one of those
+**     processes uses nolock=1.
+**
+**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
+**     parameter that indicates that the database file is stored on
+**     read-only media.  ^When immutable is set, SQLite assumes that the
+**     database file cannot be changed, even by a process with higher
+**     privilege, and so the database is opened read-only and all locking
+**     and change detection is disabled.  Caution: Setting the immutable
+**     property on a database file that does in fact change can result
+**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
+**     See also: [SQLITE_IOCAP_IMMUTABLE].
+**
+** </ul>
+**
+** ^Specifying an unknown parameter in the query component of a URI is not an
+** error.  Future versions of SQLite might understand additional query
+** parameters.  See "[query parameters with special meaning to SQLite]" for
+** additional information.
+**
+** [[URI filename examples]] <h3>URI filename examples</h3>
+**
+** <table border="1" align=center cellpadding=5>
+** <tr><th> URI filenames <th> Results
+** <tr><td> file:data.db <td>
+**          Open the file "data.db" in the current directory.
+** <tr><td> file:/home/fred/data.db<br>
+**          file:///home/fred/data.db <br>
+**          file://localhost/home/fred/data.db <br> <td>
+**          Open the database file "/home/fred/data.db".
+** <tr><td> file://darkstar/home/fred/data.db <td>
+**          An error. "darkstar" is not a recognized authority.
+** <tr><td style="white-space:nowrap">
+**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
+**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
+**          C:. Note that the %20 escaping in this example is not strictly
+**          necessary - space characters can be used literally
+**          in URI filenames.
+** <tr><td> file:data.db?mode=ro&cache=private <td>
+**          Open file "data.db" in the current directory for read-only access.
+**          Regardless of whether or not shared-cache mode is enabled by
+**          default, use a private cache.
+** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
+**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
+**          that uses dot-files in place of posix advisory locking.
+** <tr><td> file:data.db?mode=readonly <td>
+**          An error. "readonly" is not a valid option for the "mode" parameter.
+**          Use "ro" instead:  "file:data.db?mode=ro".
+** </table>
+**
+** ^URI hexadecimal escape sequences (%HH) are supported within the path and
+** query components of a URI. A hexadecimal escape sequence consists of a
+** percent sign - "%" - followed by exactly two hexadecimal digits
+** specifying an octet value. ^Before the path or query components of a
+** URI filename are interpreted, they are encoded using UTF-8 and all
+** hexadecimal escape sequences replaced by a single byte containing the
+** corresponding octet. If this process generates an invalid UTF-8 encoding,
+** the results are undefined.
+**
+** <b>Note to Windows users:</b>  The encoding used for the filename argument
+** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
+** codepage is currently defined.  Filenames containing international
+** characters must be converted to UTF-8 prior to passing them into
+** sqlite3_open() or sqlite3_open_v2().
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
+** features that require the use of temporary files may fail.
+**
+** See also: [sqlite3_temp_directory]
+*/
+SQLITE_API int sqlite3_open(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open16(
+  const void *filename,   /* Database filename (UTF-16) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open_v2(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb,         /* OUT: SQLite db handle */
+  int flags,              /* Flags */
+  const char *zVfs        /* Name of VFS module to use */
+);
+
+/*
+** CAPI3REF: Obtain Values For URI Parameters
+**
+** These are utility routines, useful to [VFS|custom VFS implementations],
+** that check if a database file was a URI that contained a specific query
+** parameter, and if so obtains the value of that query parameter.
+**
+** The first parameter to these interfaces (hereafter referred to
+** as F) must be one of:
+** <ul>
+** <li> A database filename pointer created by the SQLite core and
+** passed into the xOpen() method of a VFS implementation, or
+** <li> A filename obtained from [sqlite3_db_filename()], or
+** <li> A new filename constructed using [sqlite3_create_filename()].
+** </ul>
+** If the F parameter is not one of the above, then the behavior is
+** undefined and probably undesirable.  Older versions of SQLite were
+** more tolerant of invalid F parameters than newer versions.
+**
+** If F is a suitable filename (as described in the previous paragraph)
+** and if P is the name of the query parameter, then
+** sqlite3_uri_parameter(F,P) returns the value of the P
+** parameter if it exists or a NULL pointer if P does not appear as a
+** query parameter on F.  If P is a query parameter of F and it
+** has no explicit value, then sqlite3_uri_parameter(F,P) returns
+** a pointer to an empty string.
+**
+** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
+** parameter and returns true (1) or false (0) according to the value
+** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
+** value of query parameter P is one of "yes", "true", or "on" in any
+** case or if the value begins with a non-zero number.  The
+** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
+** query parameter P is one of "no", "false", or "off" in any case or
+** if the value begins with a numeric zero.  If P is not a query
+** parameter on F or if the value of P does not match any of the
+** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
+**
+** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
+** 64-bit signed integer and returns that integer, or D if P does not
+** exist.  If the value of P is something other than an integer, then
+** zero is returned.
+**
+** The sqlite3_uri_key(F,N) returns a pointer to the name (not
+** the value) of the N-th query parameter for filename F, or a NULL
+** pointer if N is less than zero or greater than the number of query
+** parameters minus 1.  The N value is zero-based so N should be 0 to obtain
+** the name of the first query parameter, 1 for the second parameter, and
+** so forth.
+**
+** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
+** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
+** is not a database file pathname pointer that the SQLite core passed
+** into the xOpen VFS method, then the behavior of this routine is undefined
+** and probably undesirable.
+**
+** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
+** parameter can also be the name of a rollback journal file or WAL file
+** in addition to the main database file.  Prior to version 3.31.0, these
+** routines would only work if F was the name of the main database file.
+** When the F parameter is the name of the rollback journal or WAL file,
+** it has access to all the same query parameters as were found on the
+** main database file.
+**
+** See the [URI filename] documentation for additional information.
+*/
+SQLITE_API const char *sqlite3_uri_parameter(sqlite3_filename z, const char *zParam);
+SQLITE_API int sqlite3_uri_boolean(sqlite3_filename z, const char *zParam, int bDefault);
+SQLITE_API sqlite3_int64 sqlite3_uri_int64(sqlite3_filename, const char*, sqlite3_int64);
+SQLITE_API const char *sqlite3_uri_key(sqlite3_filename z, int N);
+
+/*
+** CAPI3REF:  Translate filenames
+**
+** These routines are available to [VFS|custom VFS implementations] for
+** translating filenames between the main database file, the journal file,
+** and the WAL file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
+** returns the name of the corresponding database file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** passed by the SQLite core into the VFS, or if F is a database filename
+** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
+** returns the name of the corresponding rollback journal file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** that was passed by the SQLite core into the VFS, or if F is a database
+** filename obtained from [sqlite3_db_filename()], then
+** sqlite3_filename_wal(F) returns the name of the corresponding
+** WAL file.
+**
+** In all of the above, if F is not the name of a database, journal or WAL
+** filename passed into the VFS from the SQLite core and F is not the
+** return value from [sqlite3_db_filename()], then the result is
+** undefined and is likely a memory access violation.
+*/
+SQLITE_API const char *sqlite3_filename_database(sqlite3_filename);
+SQLITE_API const char *sqlite3_filename_journal(sqlite3_filename);
+SQLITE_API const char *sqlite3_filename_wal(sqlite3_filename);
+
+/*
+** CAPI3REF:  Database File Corresponding To A Journal
+**
+** ^If X is the name of a rollback or WAL-mode journal file that is
+** passed into the xOpen method of [sqlite3_vfs], then
+** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
+** object that represents the main database file.
+**
+** This routine is intended for use in custom [VFS] implementations
+** only.  It is not a general-purpose interface.
+** The argument sqlite3_file_object(X) must be a filename pointer that
+** has been passed into [sqlite3_vfs].xOpen method where the
+** flags parameter to xOpen contains one of the bits
+** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL].  Any other use
+** of this routine results in undefined and probably undesirable
+** behavior.
+*/
+SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
+
+/*
+** CAPI3REF: Create and Destroy VFS Filenames
+**
+** These interfaces are provided for use by [VFS shim] implementations and
+** are not useful outside of that context.
+**
+** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
+** database filename D with corresponding journal file J and WAL file W and
+** with N URI parameters key/values pairs in the array P.  The result from
+** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
+** is safe to pass to routines like:
+** <ul>
+** <li> [sqlite3_uri_parameter()],
+** <li> [sqlite3_uri_boolean()],
+** <li> [sqlite3_uri_int64()],
+** <li> [sqlite3_uri_key()],
+** <li> [sqlite3_filename_database()],
+** <li> [sqlite3_filename_journal()], or
+** <li> [sqlite3_filename_wal()].
+** </ul>
+** If a memory allocation error occurs, sqlite3_create_filename() might
+** return a NULL pointer.  The memory obtained from sqlite3_create_filename(X)
+** must be released by a corresponding call to sqlite3_free_filename(Y).
+**
+** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
+** of 2*N pointers to strings.  Each pair of pointers in this array corresponds
+** to a key and value for a query parameter.  The P parameter may be a NULL
+** pointer if N is zero.  None of the 2*N pointers in the P array may be
+** NULL pointers and key pointers should not be empty strings.
+** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
+** be NULL pointers, though they can be empty strings.
+**
+** The sqlite3_free_filename(Y) routine releases a memory allocation
+** previously obtained from sqlite3_create_filename().  Invoking
+** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
+**
+** If the Y parameter to sqlite3_free_filename(Y) is anything other
+** than a NULL pointer or a pointer previously acquired from
+** sqlite3_create_filename(), then bad things such as heap
+** corruption or segfaults may occur. The value Y should not be
+** used again after sqlite3_free_filename(Y) has been called.  This means
+** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
+** then the corresponding [sqlite3_module.xClose() method should also be
+** invoked prior to calling sqlite3_free_filename(Y).
+*/
+SQLITE_API sqlite3_filename sqlite3_create_filename(
+  const char *zDatabase,
+  const char *zJournal,
+  const char *zWal,
+  int nParam,
+  const char **azParam
+);
+SQLITE_API void sqlite3_free_filename(sqlite3_filename);
+
+/*
+** CAPI3REF: Error Codes And Messages
+** METHOD: sqlite3
+**
+** ^If the most recent sqlite3_* API call associated with
+** [database connection] D failed, then the sqlite3_errcode(D) interface
+** returns the numeric [result code] or [extended result code] for that
+** API call.
+** ^The sqlite3_extended_errcode()
+** interface is the same except that it always returns the
+** [extended result code] even when extended result codes are
+** disabled.
+**
+** The values returned by sqlite3_errcode() and/or
+** sqlite3_extended_errcode() might change with each API call.
+** Except, there are some interfaces that are guaranteed to never
+** change the value of the error code.  The error-code preserving
+** interfaces include the following:
+**
+** <ul>
+** <li> sqlite3_errcode()
+** <li> sqlite3_extended_errcode()
+** <li> sqlite3_errmsg()
+** <li> sqlite3_errmsg16()
+** <li> sqlite3_error_offset()
+** </ul>
+**
+** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
+** text that describes the error, as either UTF-8 or UTF-16 respectively,
+** or NULL if no error message is available.
+** (See how SQLite handles [invalid UTF] for exceptions to this rule.)
+** ^(Memory to hold the error message string is managed internally.
+** The application does not need to worry about freeing the result.
+** However, the error string might be overwritten or deallocated by
+** subsequent calls to other SQLite interface functions.)^
+**
+** ^The sqlite3_errstr(E) interface returns the English-language text
+** that describes the [result code] E, as UTF-8, or NULL if E is not an
+** result code for which a text error message is available.
+** ^(Memory to hold the error message string is managed internally
+** and must not be freed by the application)^.
+**
+** ^If the most recent error references a specific token in the input
+** SQL, the sqlite3_error_offset() interface returns the byte offset
+** of the start of that token.  ^The byte offset returned by
+** sqlite3_error_offset() assumes that the input SQL is UTF8.
+** ^If the most recent error does not reference a specific token in the input
+** SQL, then the sqlite3_error_offset() function returns -1.
+**
+** When the serialized [threading mode] is in use, it might be the
+** case that a second error occurs on a separate thread in between
+** the time of the first error and the call to these interfaces.
+** When that happens, the second error will be reported since these
+** interfaces always report the most recent result.  To avoid
+** this, each thread can obtain exclusive use of the [database connection] D
+** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
+** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
+** all calls to the interfaces listed here are completed.
+**
+** If an interface fails with SQLITE_MISUSE, that means the interface
+** was invoked incorrectly by the application.  In that case, the
+** error code and message may or may not be set.
+*/
+SQLITE_API int sqlite3_errcode(sqlite3 *db);
+SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
+SQLITE_API const char *sqlite3_errmsg(sqlite3*);
+SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
+SQLITE_API const char *sqlite3_errstr(int);
+SQLITE_API int sqlite3_error_offset(sqlite3 *db);
+
+/*
+** CAPI3REF: Prepared Statement Object
+** KEYWORDS: {prepared statement} {prepared statements}
+**
+** An instance of this object represents a single SQL statement that
+** has been compiled into binary form and is ready to be evaluated.
+**
+** Think of each SQL statement as a separate computer program.  The
+** original SQL text is source code.  A prepared statement object
+** is the compiled object code.  All SQL must be converted into a
+** prepared statement before it can be run.
+**
+** The life-cycle of a prepared statement object usually goes like this:
+**
+** <ol>
+** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
+** <li> Bind values to [parameters] using the sqlite3_bind_*()
+**      interfaces.
+** <li> Run the SQL by calling [sqlite3_step()] one or more times.
+** <li> Reset the prepared statement using [sqlite3_reset()] then go back
+**      to step 2.  Do this zero or more times.
+** <li> Destroy the object using [sqlite3_finalize()].
+** </ol>
+*/
+typedef struct sqlite3_stmt sqlite3_stmt;
+
+/*
+** CAPI3REF: Run-time Limits
+** METHOD: sqlite3
+**
+** ^(This interface allows the size of various constructs to be limited
+** on a connection by connection basis.  The first parameter is the
+** [database connection] whose limit is to be set or queried.  The
+** second parameter is one of the [limit categories] that define a
+** class of constructs to be size limited.  The third parameter is the
+** new limit for that construct.)^
+**
+** ^If the new limit is a negative number, the limit is unchanged.
+** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
+** [limits | hard upper bound]
+** set at compile-time by a C preprocessor macro called
+** [limits | SQLITE_MAX_<i>NAME</i>].
+** (The "_LIMIT_" in the name is changed to "_MAX_".))^
+** ^Attempts to increase a limit above its hard upper bound are
+** silently truncated to the hard upper bound.
+**
+** ^Regardless of whether or not the limit was changed, the
+** [sqlite3_limit()] interface returns the prior value of the limit.
+** ^Hence, to find the current value of a limit without changing it,
+** simply invoke this interface with the third parameter set to -1.
+**
+** Run-time limits are intended for use in applications that manage
+** both their own internal database and also databases that are controlled
+** by untrusted external sources.  An example application might be a
+** web browser that has its own databases for storing history and
+** separate databases controlled by JavaScript applications downloaded
+** off the Internet.  The internal databases can be given the
+** large, default limits.  Databases managed by external sources can
+** be given much smaller limits designed to prevent a denial of service
+** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
+** interface to further control untrusted SQL.  The size of the database
+** created by an untrusted script can be contained using the
+** [max_page_count] [PRAGMA].
+**
+** New run-time limit categories may be added in future releases.
+*/
+SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
+
+/*
+** CAPI3REF: Run-Time Limit Categories
+** KEYWORDS: {limit category} {*limit categories}
+**
+** These constants define various performance limits
+** that can be lowered at run-time using [sqlite3_limit()].
+** The synopsis of the meanings of the various limits is shown below.
+** Additional information is available at [limits | Limits in SQLite].
+**
+** <dl>
+** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
+** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
+**
+** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
+** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
+**
+** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
+** <dd>The maximum number of columns in a table definition or in the
+** result set of a [SELECT] or the maximum number of columns in an index
+** or in an ORDER BY or GROUP BY clause.</dd>)^
+**
+** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
+** <dd>The maximum depth of the parse tree on any expression.</dd>)^
+**
+** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
+** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
+**
+** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
+** <dd>The maximum number of instructions in a virtual machine program
+** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
+** the equivalent tries to allocate space for more than this many opcodes
+** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
+**
+** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
+** <dd>The maximum number of arguments on a function.</dd>)^
+**
+** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
+** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
+**
+** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
+** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
+** <dd>The maximum length of the pattern argument to the [LIKE] or
+** [GLOB] operators.</dd>)^
+**
+** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
+** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
+** <dd>The maximum index number of any [parameter] in an SQL statement.)^
+**
+** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
+** <dd>The maximum depth of recursion for triggers.</dd>)^
+**
+** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
+** <dd>The maximum number of auxiliary worker threads that a single
+** [prepared statement] may start.</dd>)^
+** </dl>
+*/
+#define SQLITE_LIMIT_LENGTH                    0
+#define SQLITE_LIMIT_SQL_LENGTH                1
+#define SQLITE_LIMIT_COLUMN                    2
+#define SQLITE_LIMIT_EXPR_DEPTH                3
+#define SQLITE_LIMIT_COMPOUND_SELECT           4
+#define SQLITE_LIMIT_VDBE_OP                   5
+#define SQLITE_LIMIT_FUNCTION_ARG              6
+#define SQLITE_LIMIT_ATTACHED                  7
+#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
+#define SQLITE_LIMIT_VARIABLE_NUMBER           9
+#define SQLITE_LIMIT_TRIGGER_DEPTH            10
+#define SQLITE_LIMIT_WORKER_THREADS           11
+
+/*
+** CAPI3REF: Prepare Flags
+**
+** These constants define various flags that can be passed into
+** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
+** [sqlite3_prepare16_v3()] interfaces.
+**
+** New flags may be added in future releases of SQLite.
+**
+** <dl>
+** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
+** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
+** that the prepared statement will be retained for a long time and
+** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
+** and [sqlite3_prepare16_v3()] assume that the prepared statement will
+** be used just once or at most a few times and then destroyed using
+** [sqlite3_finalize()] relatively soon. The current implementation acts
+** on this hint by avoiding the use of [lookaside memory] so as not to
+** deplete the limited store of lookaside memory. Future versions of
+** SQLite may act on this hint differently.
+**
+** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
+** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
+** to be required for any prepared statement that wanted to use the
+** [sqlite3_normalized_sql()] interface.  However, the
+** [sqlite3_normalized_sql()] interface is now available to all
+** prepared statements, regardless of whether or not they use this
+** flag.
+**
+** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
+** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
+** to return an error (error code SQLITE_ERROR) if the statement uses
+** any virtual tables.
+**
+** [[SQLITE_PREPARE_DONT_LOG]] <dt>SQLITE_PREPARE_DONT_LOG</dt>
+** <dd>The SQLITE_PREPARE_DONT_LOG flag prevents SQL compiler
+** errors from being sent to the error log defined by
+** [SQLITE_CONFIG_LOG].  This can be used, for example, to do test
+** compiles to see if some SQL syntax is well-formed, without generating
+** messages on the global error log when it is not.  If the test compile
+** fails, the sqlite3_prepare_v3() call returns the same error indications
+** with or without this flag; it just omits the call to [sqlite3_log()] that
+** logs the error.
+** </dl>
+*/
+#define SQLITE_PREPARE_PERSISTENT              0x01
+#define SQLITE_PREPARE_NORMALIZE               0x02
+#define SQLITE_PREPARE_NO_VTAB                 0x04
+#define SQLITE_PREPARE_DONT_LOG                0x10
+
+/*
+** CAPI3REF: Compiling An SQL Statement
+** KEYWORDS: {SQL statement compiler}
+** METHOD: sqlite3
+** CONSTRUCTOR: sqlite3_stmt
+**
+** To execute an SQL statement, it must first be compiled into a byte-code
+** program using one of these routines.  Or, in other words, these routines
+** are constructors for the [prepared statement] object.
+**
+** The preferred routine to use is [sqlite3_prepare_v2()].  The
+** [sqlite3_prepare()] interface is legacy and should be avoided.
+** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
+** for special purposes.
+**
+** The use of the UTF-8 interfaces is preferred, as SQLite currently
+** does all parsing using UTF-8.  The UTF-16 interfaces are provided
+** as a convenience.  The UTF-16 interfaces work by converting the
+** input text into UTF-8, then invoking the corresponding UTF-8 interface.
+**
+** The first argument, "db", is a [database connection] obtained from a
+** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
+** [sqlite3_open16()].  The database connection must not have been closed.
+**
+** The second argument, "zSql", is the statement to be compiled, encoded
+** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
+** and sqlite3_prepare_v3()
+** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
+** and sqlite3_prepare16_v3() use UTF-16.
+**
+** ^If the nByte argument is negative, then zSql is read up to the
+** first zero terminator. ^If nByte is positive, then it is the maximum
+** number of bytes read from zSql.  When nByte is positive, zSql is read
+** up to the first zero terminator or until the nByte bytes have been read,
+** whichever comes first.  ^If nByte is zero, then no prepared
+** statement is generated.
+** If the caller knows that the supplied string is nul-terminated, then
+** there is a small performance advantage to passing an nByte parameter that
+** is the number of bytes in the input string <i>including</i>
+** the nul-terminator.
+** Note that nByte measure the length of the input in bytes, not
+** characters, even for the UTF-16 interfaces.
+**
+** ^If pzTail is not NULL then *pzTail is made to point to the first byte
+** past the end of the first SQL statement in zSql.  These routines only
+** compile the first statement in zSql, so *pzTail is left pointing to
+** what remains uncompiled.
+**
+** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
+** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
+** to NULL.  ^If the input text contains no SQL (if the input is an empty
+** string or a comment) then *ppStmt is set to NULL.
+** The calling procedure is responsible for deleting the compiled
+** SQL statement using [sqlite3_finalize()] after it has finished with it.
+** ppStmt may not be NULL.
+**
+** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
+** otherwise an [error code] is returned.
+**
+** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
+** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
+** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
+** are retained for backwards compatibility, but their use is discouraged.
+** ^In the "vX" interfaces, the prepared statement
+** that is returned (the [sqlite3_stmt] object) contains a copy of the
+** original SQL text. This causes the [sqlite3_step()] interface to
+** behave differently in three ways:
+**
+** <ol>
+** <li>
+** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
+** always used to do, [sqlite3_step()] will automatically recompile the SQL
+** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
+** retries will occur before sqlite3_step() gives up and returns an error.
+** </li>
+**
+** <li>
+** ^When an error occurs, [sqlite3_step()] will return one of the detailed
+** [error codes] or [extended error codes].  ^The legacy behavior was that
+** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
+** and the application would have to make a second call to [sqlite3_reset()]
+** in order to find the underlying cause of the problem. With the "v2" prepare
+** interfaces, the underlying reason for the error is returned immediately.
+** </li>
+**
+** <li>
+** ^If the specific value bound to a [parameter | host parameter] in the
+** WHERE clause might influence the choice of query plan for a statement,
+** then the statement will be automatically recompiled, as if there had been
+** a schema change, on the first [sqlite3_step()] call following any change
+** to the [sqlite3_bind_text | bindings] of that [parameter].
+** ^The specific value of a WHERE-clause [parameter] might influence the
+** choice of query plan if the parameter is the left-hand side of a [LIKE]
+** or [GLOB] operator or if the parameter is compared to an indexed column
+** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
+** </li>
+** </ol>
+**
+** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
+** the extra prepFlags parameter, which is a bit array consisting of zero or
+** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
+** sqlite3_prepare_v2() interface works exactly the same as
+** sqlite3_prepare_v3() with a zero prepFlags parameter.
+*/
+SQLITE_API int sqlite3_prepare(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare_v2(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare_v3(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16_v2(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16_v3(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+
+/*
+** CAPI3REF: Retrieving Statement SQL
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
+** SQL text used to create [prepared statement] P if P was
+** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
+** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
+** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
+** string containing the SQL text of prepared statement P with
+** [bound parameters] expanded.
+** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
+** string containing the normalized SQL text of prepared statement P.  The
+** semantics used to normalize a SQL statement are unspecified and subject
+** to change.  At a minimum, literal values will be replaced with suitable
+** placeholders.
+**
+** ^(For example, if a prepared statement is created using the SQL
+** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
+** and parameter :xyz is unbound, then sqlite3_sql() will return
+** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
+** will return "SELECT 2345,NULL".)^
+**
+** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
+** is available to hold the result, or if the result would exceed the
+** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
+**
+** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
+** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
+** option causes sqlite3_expanded_sql() to always return NULL.
+**
+** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
+** are managed by SQLite and are automatically freed when the prepared
+** statement is finalized.
+** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
+** is obtained from [sqlite3_malloc()] and must be freed by the application
+** by passing it to [sqlite3_free()].
+**
+** ^The sqlite3_normalized_sql() interface is only available if
+** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
+*/
+SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
+SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
+#ifdef SQLITE_ENABLE_NORMALIZE
+SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
+#endif
+
+/*
+** CAPI3REF: Determine If An SQL Statement Writes The Database
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
+** and only if the [prepared statement] X makes no direct changes to
+** the content of the database file.
+**
+** Note that [application-defined SQL functions] or
+** [virtual tables] might change the database indirectly as a side effect.
+** ^(For example, if an application defines a function "eval()" that
+** calls [sqlite3_exec()], then the following SQL statement would
+** change the database file through side-effects:
+**
+** <blockquote><pre>
+**    SELECT eval('DELETE FROM t1') FROM t2;
+** </pre></blockquote>
+**
+** But because the [SELECT] statement does not change the database file
+** directly, sqlite3_stmt_readonly() would still return true.)^
+**
+** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
+** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
+** since the statements themselves do not actually modify the database but
+** rather they control the timing of when other statements modify the
+** database.  ^The [ATTACH] and [DETACH] statements also cause
+** sqlite3_stmt_readonly() to return true since, while those statements
+** change the configuration of a database connection, they do not make
+** changes to the content of the database files on disk.
+** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
+** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
+** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
+** sqlite3_stmt_readonly() returns false for those commands.
+**
+** ^This routine returns false if there is any possibility that the
+** statement might change the database file.  ^A false return does
+** not guarantee that the statement will change the database file.
+** ^For example, an UPDATE statement might have a WHERE clause that
+** makes it a no-op, but the sqlite3_stmt_readonly() result would still
+** be false.  ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
+** read-only no-op if the table already exists, but
+** sqlite3_stmt_readonly() still returns false for such a statement.
+**
+** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
+** statement, then sqlite3_stmt_readonly(X) returns the same value as
+** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
+*/
+SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
+** prepared statement S is an EXPLAIN statement, or 2 if the
+** statement S is an EXPLAIN QUERY PLAN.
+** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
+** an ordinary statement or a NULL pointer.
+*/
+SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Change The EXPLAIN Setting For A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** The sqlite3_stmt_explain(S,E) interface changes the EXPLAIN
+** setting for [prepared statement] S.  If E is zero, then S becomes
+** a normal prepared statement.  If E is 1, then S behaves as if
+** its SQL text began with "[EXPLAIN]".  If E is 2, then S behaves as if
+** its SQL text began with "[EXPLAIN QUERY PLAN]".
+**
+** Calling sqlite3_stmt_explain(S,E) might cause S to be reprepared.
+** SQLite tries to avoid a reprepare, but a reprepare might be necessary
+** on the first transition into EXPLAIN or EXPLAIN QUERY PLAN mode.
+**
+** Because of the potential need to reprepare, a call to
+** sqlite3_stmt_explain(S,E) will fail with SQLITE_ERROR if S cannot be
+** reprepared because it was created using [sqlite3_prepare()] instead of
+** the newer [sqlite3_prepare_v2()] or [sqlite3_prepare_v3()] interfaces and
+** hence has no saved SQL text with which to reprepare.
+**
+** Changing the explain setting for a prepared statement does not change
+** the original SQL text for the statement.  Hence, if the SQL text originally
+** began with EXPLAIN or EXPLAIN QUERY PLAN, but sqlite3_stmt_explain(S,0)
+** is called to convert the statement into an ordinary statement, the EXPLAIN
+** or EXPLAIN QUERY PLAN keywords will still appear in the sqlite3_sql(S)
+** output, even though the statement now acts like a normal SQL statement.
+**
+** This routine returns SQLITE_OK if the explain mode is successfully
+** changed, or an error code if the explain mode could not be changed.
+** The explain mode cannot be changed while a statement is active.
+** Hence, it is good practice to call [sqlite3_reset(S)]
+** immediately prior to calling sqlite3_stmt_explain(S,E).
+*/
+SQLITE_API int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode);
+
+/*
+** CAPI3REF: Determine If A Prepared Statement Has Been Reset
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
+** [prepared statement] S has been stepped at least once using
+** [sqlite3_step(S)] but has neither run to completion (returned
+** [SQLITE_DONE] from [sqlite3_step(S)]) nor
+** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
+** interface returns false if S is a NULL pointer.  If S is not a
+** NULL pointer and is not a pointer to a valid [prepared statement]
+** object, then the behavior is undefined and probably undesirable.
+**
+** This interface can be used in combination [sqlite3_next_stmt()]
+** to locate all prepared statements associated with a database
+** connection that are in need of being reset.  This can be used,
+** for example, in diagnostic routines to search for prepared
+** statements that are holding a transaction open.
+*/
+SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Dynamically Typed Value Object
+** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
+**
+** SQLite uses the sqlite3_value object to represent all values
+** that can be stored in a database table. SQLite uses dynamic typing
+** for the values it stores.  ^Values stored in sqlite3_value objects
+** can be integers, floating point values, strings, BLOBs, or NULL.
+**
+** An sqlite3_value object may be either "protected" or "unprotected".
+** Some interfaces require a protected sqlite3_value.  Other interfaces
+** will accept either a protected or an unprotected sqlite3_value.
+** Every interface that accepts sqlite3_value arguments specifies
+** whether or not it requires a protected sqlite3_value.  The
+** [sqlite3_value_dup()] interface can be used to construct a new
+** protected sqlite3_value from an unprotected sqlite3_value.
+**
+** The terms "protected" and "unprotected" refer to whether or not
+** a mutex is held.  An internal mutex is held for a protected
+** sqlite3_value object but no mutex is held for an unprotected
+** sqlite3_value object.  If SQLite is compiled to be single-threaded
+** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
+** or if SQLite is run in one of reduced mutex modes
+** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
+** then there is no distinction between protected and unprotected
+** sqlite3_value objects and they can be used interchangeably.  However,
+** for maximum code portability it is recommended that applications
+** still make the distinction between protected and unprotected
+** sqlite3_value objects even when not strictly required.
+**
+** ^The sqlite3_value objects that are passed as parameters into the
+** implementation of [application-defined SQL functions] are protected.
+** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
+** are protected.
+** ^The sqlite3_value object returned by
+** [sqlite3_column_value()] is unprotected.
+** Unprotected sqlite3_value objects may only be used as arguments
+** to [sqlite3_result_value()], [sqlite3_bind_value()], and
+** [sqlite3_value_dup()].
+** The [sqlite3_value_blob | sqlite3_value_type()] family of
+** interfaces require protected sqlite3_value objects.
+*/
+typedef struct sqlite3_value sqlite3_value;
+
+/*
+** CAPI3REF: SQL Function Context Object
+**
+** The context in which an SQL function executes is stored in an
+** sqlite3_context object.  ^A pointer to an sqlite3_context object
+** is always first parameter to [application-defined SQL functions].
+** The application-defined SQL function implementation will pass this
+** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
+** [sqlite3_aggregate_context()], [sqlite3_user_data()],
+** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
+** and/or [sqlite3_set_auxdata()].
+*/
+typedef struct sqlite3_context sqlite3_context;
+
+/*
+** CAPI3REF: Binding Values To Prepared Statements
+** KEYWORDS: {host parameter} {host parameters} {host parameter name}
+** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
+** METHOD: sqlite3_stmt
+**
+** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
+** literals may be replaced by a [parameter] that matches one of following
+** templates:
+**
+** <ul>
+** <li>  ?
+** <li>  ?NNN
+** <li>  :VVV
+** <li>  @VVV
+** <li>  $VVV
+** </ul>
+**
+** In the templates above, NNN represents an integer literal,
+** and VVV represents an alphanumeric identifier.)^  ^The values of these
+** parameters (also called "host parameter names" or "SQL parameters")
+** can be set using the sqlite3_bind_*() routines defined here.
+**
+** ^The first argument to the sqlite3_bind_*() routines is always
+** a pointer to the [sqlite3_stmt] object returned from
+** [sqlite3_prepare_v2()] or its variants.
+**
+** ^The second argument is the index of the SQL parameter to be set.
+** ^The leftmost SQL parameter has an index of 1.  ^When the same named
+** SQL parameter is used more than once, second and subsequent
+** occurrences have the same index as the first occurrence.
+** ^The index for named parameters can be looked up using the
+** [sqlite3_bind_parameter_index()] API if desired.  ^The index
+** for "?NNN" parameters is the value of NNN.
+** ^The NNN value must be between 1 and the [sqlite3_limit()]
+** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
+**
+** ^The third argument is the value to bind to the parameter.
+** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
+** is ignored and the end result is the same as sqlite3_bind_null().
+** ^If the third parameter to sqlite3_bind_text() is not NULL, then
+** it should be a pointer to well-formed UTF8 text.
+** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
+** it should be a pointer to well-formed UTF16 text.
+** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
+** it should be a pointer to a well-formed unicode string that is
+** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
+** otherwise.
+**
+** [[byte-order determination rules]] ^The byte-order of
+** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
+** found in first character, which is removed, or in the absence of a BOM
+** the byte order is the native byte order of the host
+** machine for sqlite3_bind_text16() or the byte order specified in
+** the 6th parameter for sqlite3_bind_text64().)^
+** ^If UTF16 input text contains invalid unicode
+** characters, then SQLite might change those invalid characters
+** into the unicode replacement character: U+FFFD.
+**
+** ^(In those routines that have a fourth argument, its value is the
+** number of bytes in the parameter.  To be clear: the value is the
+** number of <u>bytes</u> in the value, not the number of characters.)^
+** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** is negative, then the length of the string is
+** the number of bytes up to the first zero terminator.
+** If the fourth parameter to sqlite3_bind_blob() is negative, then
+** the behavior is undefined.
+** If a non-negative fourth parameter is provided to sqlite3_bind_text()
+** or sqlite3_bind_text16() or sqlite3_bind_text64() then
+** that parameter must be the byte offset
+** where the NUL terminator would occur assuming the string were NUL
+** terminated.  If any NUL characters occurs at byte offsets less than
+** the value of the fourth parameter then the resulting string value will
+** contain embedded NULs.  The result of expressions involving strings
+** with embedded NULs is undefined.
+**
+** ^The fifth argument to the BLOB and string binding interfaces controls
+** or indicates the lifetime of the object referenced by the third parameter.
+** These three options exist:
+** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
+** with it may be passed. ^It is called to dispose of the BLOB or string even
+** if the call to the bind API fails, except the destructor is not called if
+** the third parameter is a NULL pointer or the fourth parameter is negative.
+** ^ (2) The special constant, [SQLITE_STATIC], may be passed to indicate that
+** the application remains responsible for disposing of the object. ^In this
+** case, the object and the provided pointer to it must remain valid until
+** either the prepared statement is finalized or the same SQL parameter is
+** bound to something else, whichever occurs sooner.
+** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
+** object is to be copied prior to the return from sqlite3_bind_*(). ^The
+** object and pointer to it must remain valid until then. ^SQLite will then
+** manage the lifetime of its private copy.
+**
+** ^The sixth argument to sqlite3_bind_text64() must be one of
+** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
+** to specify the encoding of the text in the third parameter.  If
+** the sixth argument to sqlite3_bind_text64() is not one of the
+** allowed values shown above, or if the text encoding is different
+** from the encoding specified by the sixth parameter, then the behavior
+** is undefined.
+**
+** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
+** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
+** (just an integer to hold its size) while it is being processed.
+** Zeroblobs are intended to serve as placeholders for BLOBs whose
+** content is later written using
+** [sqlite3_blob_open | incremental BLOB I/O] routines.
+** ^A negative value for the zeroblob results in a zero-length BLOB.
+**
+** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
+** [prepared statement] S to have an SQL value of NULL, but to also be
+** associated with the pointer P of type T.  ^D is either a NULL pointer or
+** a pointer to a destructor function for P. ^SQLite will invoke the
+** destructor D with a single argument of P when it is finished using
+** P.  The T parameter should be a static string, preferably a string
+** literal. The sqlite3_bind_pointer() routine is part of the
+** [pointer passing interface] added for SQLite 3.20.0.
+**
+** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
+** for the [prepared statement] or with a prepared statement for which
+** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
+** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
+** routine is passed a [prepared statement] that has been finalized, the
+** result is undefined and probably harmful.
+**
+** ^Bindings are not cleared by the [sqlite3_reset()] routine.
+** ^Unbound parameters are interpreted as NULL.
+**
+** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
+** [error code] if anything goes wrong.
+** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
+** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
+** [SQLITE_MAX_LENGTH].
+** ^[SQLITE_RANGE] is returned if the parameter
+** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
+**
+** See also: [sqlite3_bind_parameter_count()],
+** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
+SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
+                        void(*)(void*));
+SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
+SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
+SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
+SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
+SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
+SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
+SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
+                         void(*)(void*), unsigned char encoding);
+SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
+SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
+SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
+SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
+
+/*
+** CAPI3REF: Number Of SQL Parameters
+** METHOD: sqlite3_stmt
+**
+** ^This routine can be used to find the number of [SQL parameters]
+** in a [prepared statement].  SQL parameters are tokens of the
+** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
+** placeholders for values that are [sqlite3_bind_blob | bound]
+** to the parameters at a later time.
+**
+** ^(This routine actually returns the index of the largest (rightmost)
+** parameter. For all forms except ?NNN, this will correspond to the
+** number of unique parameters.  If parameters of the ?NNN form are used,
+** there may be gaps in the list.)^
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_name()], and
+** [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Name Of A Host Parameter
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_bind_parameter_name(P,N) interface returns
+** the name of the N-th [SQL parameter] in the [prepared statement] P.
+** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** respectively.
+** In other words, the initial ":" or "$" or "@" or "?"
+** is included as part of the name.)^
+** ^Parameters of the form "?" without a following integer have no name
+** and are referred to as "nameless" or "anonymous parameters".
+**
+** ^The first host parameter has an index of 1, not 0.
+**
+** ^If the value N is out of range or if the N-th parameter is
+** nameless, then NULL is returned.  ^The returned string is
+** always in UTF-8 encoding even if the named parameter was
+** originally specified as UTF-16 in [sqlite3_prepare16()],
+** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
+
+/*
+** CAPI3REF: Index Of A Parameter With A Given Name
+** METHOD: sqlite3_stmt
+**
+** ^Return the index of an SQL parameter given its name.  ^The
+** index value returned is suitable for use as the second
+** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
+** is returned if no matching parameter is found.  ^The parameter
+** name must be given in UTF-8 even if the original statement
+** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
+** [sqlite3_prepare16_v3()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_name()].
+*/
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
+
+/*
+** CAPI3REF: Reset All Bindings On A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
+** the [sqlite3_bind_blob | bindings] on a [prepared statement].
+** ^Use this routine to reset all host parameters to NULL.
+*/
+SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number Of Columns In A Result Set
+** METHOD: sqlite3_stmt
+**
+** ^Return the number of columns in the result set returned by the
+** [prepared statement]. ^If this routine returns 0, that means the
+** [prepared statement] returns no data (for example an [UPDATE]).
+** ^However, just because this routine returns a positive number does not
+** mean that one or more rows of data will be returned.  ^A SELECT statement
+** will always have a positive sqlite3_column_count() but depending on the
+** WHERE clause constraints and the table content, it might return no rows.
+**
+** See also: [sqlite3_data_count()]
+*/
+SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Column Names In A Result Set
+** METHOD: sqlite3_stmt
+**
+** ^These routines return the name assigned to a particular column
+** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
+** interface returns a pointer to a zero-terminated UTF-8 string
+** and sqlite3_column_name16() returns a pointer to a zero-terminated
+** UTF-16 string.  ^The first parameter is the [prepared statement]
+** that implements the [SELECT] statement. ^The second parameter is the
+** column number.  ^The leftmost column is number 0.
+**
+** ^The returned string pointer is valid until either the [prepared statement]
+** is destroyed by [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the next call to
+** sqlite3_column_name() or sqlite3_column_name16() on the same column.
+**
+** ^If sqlite3_malloc() fails during the processing of either routine
+** (for example during a conversion from UTF-8 to UTF-16) then a
+** NULL pointer is returned.
+**
+** ^The name of a result column is the value of the "AS" clause for
+** that column, if there is an AS clause.  If there is no AS clause
+** then the name of the column is unspecified and may change from
+** one release of SQLite to the next.
+*/
+SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
+SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
+
+/*
+** CAPI3REF: Source Of Data In A Query Result
+** METHOD: sqlite3_stmt
+**
+** ^These routines provide a means to determine the database, table, and
+** table column that is the origin of a particular result column in
+** [SELECT] statement.
+** ^The name of the database or table or column can be returned as
+** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
+** the database name, the _table_ routines return the table name, and
+** the origin_ routines return the column name.
+** ^The returned string is valid until the [prepared statement] is destroyed
+** using [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the same information is requested
+** again in a different encoding.
+**
+** ^The names returned are the original un-aliased names of the
+** database, table, and column.
+**
+** ^The first argument to these interfaces is a [prepared statement].
+** ^These functions return information about the Nth result column returned by
+** the statement, where N is the second function argument.
+** ^The left-most column is column 0 for these routines.
+**
+** ^If the Nth column returned by the statement is an expression or
+** subquery and is not a column value, then all of these functions return
+** NULL.  ^These routines might also return NULL if a memory allocation error
+** occurs.  ^Otherwise, they return the name of the attached database, table,
+** or column that query result column was extracted from.
+**
+** ^As with all other SQLite APIs, those whose names end with "16" return
+** UTF-16 encoded strings and the other functions return UTF-8.
+**
+** ^These APIs are only available if the library was compiled with the
+** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
+**
+** If two or more threads call one or more
+** [sqlite3_column_database_name | column metadata interfaces]
+** for the same [prepared statement] and result column
+** at the same time then the results are undefined.
+*/
+SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
+
+/*
+** CAPI3REF: Declared Datatype Of A Query Result
+** METHOD: sqlite3_stmt
+**
+** ^(The first parameter is a [prepared statement].
+** If this statement is a [SELECT] statement and the Nth column of the
+** returned result set of that [SELECT] is a table column (not an
+** expression or subquery) then the declared type of the table
+** column is returned.)^  ^If the Nth column of the result set is an
+** expression or subquery, then a NULL pointer is returned.
+** ^The returned string is always UTF-8 encoded.
+**
+** ^(For example, given the database schema:
+**
+** CREATE TABLE t1(c1 VARIANT);
+**
+** and the following statement to be compiled:
+**
+** SELECT c1 + 1, c1 FROM t1;
+**
+** this routine would return the string "VARIANT" for the second result
+** column (i==1), and a NULL pointer for the first result column (i==0).)^
+**
+** ^SQLite uses dynamic run-time typing.  ^So just because a column
+** is declared to contain a particular type does not mean that the
+** data stored in that column is of the declared type.  SQLite is
+** strongly typed, but the typing is dynamic not static.  ^Type
+** is associated with individual values, not with the containers
+** used to hold those values.
+*/
+SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
+
+/*
+** CAPI3REF: Evaluate An SQL Statement
+** METHOD: sqlite3_stmt
+**
+** After a [prepared statement] has been prepared using any of
+** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
+** or [sqlite3_prepare16_v3()] or one of the legacy
+** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
+** must be called one or more times to evaluate the statement.
+**
+** The details of the behavior of the sqlite3_step() interface depend
+** on whether the statement was prepared using the newer "vX" interfaces
+** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
+** [sqlite3_prepare16_v2()] or the older legacy
+** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
+** new "vX" interface is recommended for new applications but the legacy
+** interface will continue to be supported.
+**
+** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
+** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
+** ^With the "v2" interface, any of the other [result codes] or
+** [extended result codes] might be returned as well.
+**
+** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
+** database locks it needs to do its job.  ^If the statement is a [COMMIT]
+** or occurs outside of an explicit transaction, then you can retry the
+** statement.  If the statement is not a [COMMIT] and occurs within an
+** explicit transaction then you should rollback the transaction before
+** continuing.
+**
+** ^[SQLITE_DONE] means that the statement has finished executing
+** successfully.  sqlite3_step() should not be called again on this virtual
+** machine without first calling [sqlite3_reset()] to reset the virtual
+** machine back to its initial state.
+**
+** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
+** is returned each time a new row of data is ready for processing by the
+** caller. The values may be accessed using the [column access functions].
+** sqlite3_step() is called again to retrieve the next row of data.
+**
+** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
+** violation) has occurred.  sqlite3_step() should not be called again on
+** the VM. More information may be found by calling [sqlite3_errmsg()].
+** ^With the legacy interface, a more specific error code (for example,
+** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
+** can be obtained by calling [sqlite3_reset()] on the
+** [prepared statement].  ^In the "v2" interface,
+** the more specific error code is returned directly by sqlite3_step().
+**
+** [SQLITE_MISUSE] means that the this routine was called inappropriately.
+** Perhaps it was called on a [prepared statement] that has
+** already been [sqlite3_finalize | finalized] or on one that had
+** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
+** be the case that the same database connection is being used by two or
+** more threads at the same moment in time.
+**
+** For all versions of SQLite up to and including 3.6.23.1, a call to
+** [sqlite3_reset()] was required after sqlite3_step() returned anything
+** other than [SQLITE_ROW] before any subsequent invocation of
+** sqlite3_step().  Failure to reset the prepared statement using
+** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
+** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
+** sqlite3_step() began
+** calling [sqlite3_reset()] automatically in this circumstance rather
+** than returning [SQLITE_MISUSE].  This is not considered a compatibility
+** break because any application that ever receives an SQLITE_MISUSE error
+** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
+** can be used to restore the legacy behavior.
+**
+** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
+** API always returns a generic error code, [SQLITE_ERROR], following any
+** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
+** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
+** specific [error codes] that better describes the error.
+** We admit that this is a goofy design.  The problem has been fixed
+** with the "v2" interface.  If you prepare all of your SQL statements
+** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
+** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
+** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
+** then the more specific [error codes] are returned directly
+** by sqlite3_step().  The use of the "vX" interfaces is recommended.
+*/
+SQLITE_API int sqlite3_step(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number of columns in a result set
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_data_count(P) interface returns the number of columns in the
+** current row of the result set of [prepared statement] P.
+** ^If prepared statement P does not have results ready to return
+** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
+** interfaces) then sqlite3_data_count(P) returns 0.
+** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
+** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
+** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
+** will return non-zero if previous call to [sqlite3_step](P) returned
+** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
+** where it always returns zero since each step of that multi-step
+** pragma returns 0 columns of data.
+**
+** See also: [sqlite3_column_count()]
+*/
+SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Fundamental Datatypes
+** KEYWORDS: SQLITE_TEXT
+**
+** ^(Every value in SQLite has one of five fundamental datatypes:
+**
+** <ul>
+** <li> 64-bit signed integer
+** <li> 64-bit IEEE floating point number
+** <li> string
+** <li> BLOB
+** <li> NULL
+** </ul>)^
+**
+** These constants are codes for each of those types.
+**
+** Note that the SQLITE_TEXT constant was also used in SQLite version 2
+** for a completely different meaning.  Software that links against both
+** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
+** SQLITE_TEXT.
+*/
+#define SQLITE_INTEGER  1
+#define SQLITE_FLOAT    2
+#define SQLITE_BLOB     4
+#define SQLITE_NULL     5
+#ifdef SQLITE_TEXT
+# undef SQLITE_TEXT
+#else
+# define SQLITE_TEXT     3
+#endif
+#define SQLITE3_TEXT     3
+
+/*
+** CAPI3REF: Result Values From A Query
+** KEYWORDS: {column access functions}
+** METHOD: sqlite3_stmt
+**
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result
+** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result
+** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result
+** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result
+** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result
+** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result
+** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an
+** [sqlite3_value|unprotected sqlite3_value] object.
+** <tr><td> <td> <td> 
+** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT result in bytes
+** <tr><td><b>sqlite3_column_bytes16  </b>
+** <td>→  <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_column_type</b><td>→<td>Default
+** datatype of the result
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
+** ^These routines return information about a single column of the current
+** result row of a query.  ^In every case the first argument is a pointer
+** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
+** that was returned from [sqlite3_prepare_v2()] or one of its variants)
+** and the second argument is the index of the column for which information
+** should be returned. ^The leftmost column of the result set has the index 0.
+** ^The number of columns in the result can be determined using
+** [sqlite3_column_count()].
+**
+** If the SQL statement does not currently point to a valid row, or if the
+** column index is out of range, the result is undefined.
+** These routines may only be called when the most recent call to
+** [sqlite3_step()] has returned [SQLITE_ROW] and neither
+** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
+** If any of these routines are called after [sqlite3_reset()] or
+** [sqlite3_finalize()] or after [sqlite3_step()] has returned
+** something other than [SQLITE_ROW], the results are undefined.
+** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
+** are called from a different thread while any of these routines
+** are pending, then the results are undefined.
+**
+** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
+** each return the value of a result column in a specific data format.  If
+** the result column is not initially in the requested format (for example,
+** if the query returns an integer but the sqlite3_column_text() interface
+** is used to extract the value) then an automatic type conversion is performed.
+**
+** ^The sqlite3_column_type() routine returns the
+** [SQLITE_INTEGER | datatype code] for the initial data type
+** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
+** The return value of sqlite3_column_type() can be used to decide which
+** of the first six interface should be used to extract the column value.
+** The value returned by sqlite3_column_type() is only meaningful if no
+** automatic type conversions have occurred for the value in question.
+** After a type conversion, the result of calling sqlite3_column_type()
+** is undefined, though harmless.  Future
+** versions of SQLite may change the behavior of sqlite3_column_type()
+** following a type conversion.
+**
+** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
+** or sqlite3_column_bytes16() interfaces can be used to determine the size
+** of that BLOB or string.
+**
+** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
+** the string to UTF-8 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
+**
+** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
+** the string to UTF-16 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes16() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
+**
+** ^The values returned by [sqlite3_column_bytes()] and
+** [sqlite3_column_bytes16()] do not include the zero terminators at the end
+** of the string.  ^For clarity: the values returned by
+** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
+** bytes in the string, not the number of characters.
+**
+** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
+** even empty strings, are always zero-terminated.  ^The return
+** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
+**
+** ^Strings returned by sqlite3_column_text16() always have the endianness
+** which is native to the platform, regardless of the text encoding set
+** for the database.
+**
+** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
+** [unprotected sqlite3_value] object.  In a multithreaded environment,
+** an unprotected sqlite3_value object may only be used safely with
+** [sqlite3_bind_value()] and [sqlite3_result_value()].
+** If the [unprotected sqlite3_value] object returned by
+** [sqlite3_column_value()] is used in any other way, including calls
+** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
+** or [sqlite3_value_bytes()], the behavior is not threadsafe.
+** Hence, the sqlite3_column_value() interface
+** is normally only useful within the implementation of
+** [application-defined SQL functions] or [virtual tables], not within
+** top-level application code.
+**
+** These routines may attempt to convert the datatype of the result.
+** ^For example, if the internal representation is FLOAT and a text result
+** is requested, [sqlite3_snprintf()] is used internally to perform the
+** conversion automatically.  ^(The following table details the conversions
+** that are applied:
+**
+** <blockquote>
+** <table border="1">
+** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
+**
+** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
+** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
+** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
+** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
+** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
+** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
+** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
+** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
+** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
+** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
+** <tr><td>  TEXT    <td>   BLOB    <td> No change
+** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
+** <tr><td>  BLOB    <td>   TEXT    <td> [CAST] to TEXT, ensure zero terminator
+** </table>
+** </blockquote>)^
+**
+** Note that when type conversions occur, pointers returned by prior
+** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
+** sqlite3_column_text16() may be invalidated.
+** Type conversions and pointer invalidations might occur
+** in the following cases:
+**
+** <ul>
+** <li> The initial content is a BLOB and sqlite3_column_text() or
+**      sqlite3_column_text16() is called.  A zero-terminator might
+**      need to be added to the string.</li>
+** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
+**      sqlite3_column_text16() is called.  The content must be converted
+**      to UTF-16.</li>
+** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
+**      sqlite3_column_text() is called.  The content must be converted
+**      to UTF-8.</li>
+** </ul>
+**
+** ^Conversions between UTF-16be and UTF-16le are always done in place and do
+** not invalidate a prior pointer, though of course the content of the buffer
+** that the prior pointer references will have been modified.  Other kinds
+** of conversion are done in place when it is possible, but sometimes they
+** are not possible and in those cases prior pointers are invalidated.
+**
+** The safest policy is to invoke these routines
+** in one of the following ways:
+**
+** <ul>
+**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
+** </ul>
+**
+** In other words, you should call sqlite3_column_text(),
+** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
+** into the desired format, then invoke sqlite3_column_bytes() or
+** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
+** to sqlite3_column_text() or sqlite3_column_blob() with calls to
+** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
+** with calls to sqlite3_column_bytes().
+**
+** ^The pointers returned are valid until a type conversion occurs as
+** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
+** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
+** and BLOBs is freed automatically.  Do not pass the pointers returned
+** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
+** [sqlite3_free()].
+**
+** As long as the input parameters are correct, these routines will only
+** fail if an out-of-memory error occurs during a format conversion.
+** Only the following subset of interfaces are subject to out-of-memory
+** errors:
+**
+** <ul>
+** <li> sqlite3_column_blob()
+** <li> sqlite3_column_text()
+** <li> sqlite3_column_text16()
+** <li> sqlite3_column_bytes()
+** <li> sqlite3_column_bytes16()
+** </ul>
+**
+** If an out-of-memory error occurs, then the return value from these
+** routines is the same as if the column had contained an SQL NULL value.
+** Valid SQL NULL returns can be distinguished from out-of-memory errors
+** by invoking the [sqlite3_errcode()] immediately after the suspect
+** return value is obtained and before any
+** other SQLite interface is called on the same [database connection].
+*/
+SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
+SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
+SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
+SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
+
+/*
+** CAPI3REF: Destroy A Prepared Statement Object
+** DESTRUCTOR: sqlite3_stmt
+**
+** ^The sqlite3_finalize() function is called to delete a [prepared statement].
+** ^If the most recent evaluation of the statement encountered no errors
+** or if the statement is never been evaluated, then sqlite3_finalize() returns
+** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
+** sqlite3_finalize(S) returns the appropriate [error code] or
+** [extended error code].
+**
+** ^The sqlite3_finalize(S) routine can be called at any point during
+** the life cycle of [prepared statement] S:
+** before statement S is ever evaluated, after
+** one or more calls to [sqlite3_reset()], or after any call
+** to [sqlite3_step()] regardless of whether or not the statement has
+** completed execution.
+**
+** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
+**
+** The application must finalize every [prepared statement] in order to avoid
+** resource leaks.  It is a grievous error for the application to try to use
+** a prepared statement after it has been finalized.  Any use of a prepared
+** statement after it has been finalized can result in undefined and
+** undesirable behavior such as segfaults and heap corruption.
+*/
+SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Reset A Prepared Statement Object
+** METHOD: sqlite3_stmt
+**
+** The sqlite3_reset() function is called to reset a [prepared statement]
+** object back to its initial state, ready to be re-executed.
+** ^Any SQL statement variables that had values bound to them using
+** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
+** Use [sqlite3_clear_bindings()] to reset the bindings.
+**
+** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
+** back to the beginning of its program.
+**
+** ^The return code from [sqlite3_reset(S)] indicates whether or not
+** the previous evaluation of prepared statement S completed successfully.
+** ^If [sqlite3_step(S)] has never before been called on S or if
+** [sqlite3_step(S)] has not been called since the previous call
+** to [sqlite3_reset(S)], then [sqlite3_reset(S)] will return
+** [SQLITE_OK].
+**
+** ^If the most recent call to [sqlite3_step(S)] for the
+** [prepared statement] S indicated an error, then
+** [sqlite3_reset(S)] returns an appropriate [error code].
+** ^The [sqlite3_reset(S)] interface might also return an [error code]
+** if there were no prior errors but the process of resetting
+** the prepared statement caused a new error. ^For example, if an
+** [INSERT] statement with a [RETURNING] clause is only stepped one time,
+** that one call to [sqlite3_step(S)] might return SQLITE_ROW but
+** the overall statement might still fail and the [sqlite3_reset(S)] call
+** might return SQLITE_BUSY if locking constraints prevent the
+** database change from committing.  Therefore, it is important that
+** applications check the return code from [sqlite3_reset(S)] even if
+** no prior call to [sqlite3_step(S)] indicated a problem.
+**
+** ^The [sqlite3_reset(S)] interface does not change the values
+** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
+*/
+SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
+
+
+/*
+** CAPI3REF: Create Or Redefine SQL Functions
+** KEYWORDS: {function creation routines}
+** METHOD: sqlite3
+**
+** ^These functions (collectively known as "function creation routines")
+** are used to add SQL functions or aggregates or to redefine the behavior
+** of existing SQL functions or aggregates. The only differences between
+** the three "sqlite3_create_function*" routines are the text encoding
+** expected for the second parameter (the name of the function being
+** created) and the presence or absence of a destructor callback for
+** the application data pointer. Function sqlite3_create_window_function()
+** is similar, but allows the user to supply the extra callback functions
+** needed by [aggregate window functions].
+**
+** ^The first parameter is the [database connection] to which the SQL
+** function is to be added.  ^If an application uses more than one database
+** connection then application-defined SQL functions must be added
+** to each database connection separately.
+**
+** ^The second parameter is the name of the SQL function to be created or
+** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
+** representation, exclusive of the zero-terminator.  ^Note that the name
+** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
+** ^Any attempt to create a function with a longer name
+** will result in [SQLITE_MISUSE] being returned.
+**
+** ^The third parameter (nArg)
+** is the number of arguments that the SQL function or
+** aggregate takes. ^If this parameter is -1, then the SQL function or
+** aggregate may take any number of arguments between 0 and the limit
+** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
+** parameter is less than -1 or greater than 127 then the behavior is
+** undefined.
+**
+** ^The fourth parameter, eTextRep, specifies what
+** [SQLITE_UTF8 | text encoding] this SQL function prefers for
+** its parameters.  The application should set this parameter to
+** [SQLITE_UTF16LE] if the function implementation invokes
+** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
+** implementation invokes [sqlite3_value_text16be()] on an input, or
+** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
+** otherwise.  ^The same SQL function may be registered multiple times using
+** different preferred text encodings, with different implementations for
+** each encoding.
+** ^When multiple implementations of the same function are available, SQLite
+** will pick the one that involves the least amount of data conversion.
+**
+** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
+** to signal that the function will always return the same result given
+** the same inputs within a single SQL statement.  Most SQL functions are
+** deterministic.  The built-in [random()] SQL function is an example of a
+** function that is not deterministic.  The SQLite query planner is able to
+** perform additional optimizations on deterministic functions, so use
+** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
+**
+** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
+** flag, which if present prevents the function from being invoked from
+** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
+** index expressions, or the WHERE clause of partial indexes.
+**
+** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
+** all application-defined SQL functions that do not need to be
+** used inside of triggers, view, CHECK constraints, or other elements of
+** the database schema.  This flags is especially recommended for SQL
+** functions that have side effects or reveal internal application state.
+** Without this flag, an attacker might be able to modify the schema of
+** a database file to include invocations of the function with parameters
+** chosen by the attacker, which the application will then execute when
+** the database file is opened and read.
+**
+** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
+** function can gain access to this pointer using [sqlite3_user_data()].)^
+**
+** ^The sixth, seventh and eighth parameters passed to the three
+** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
+** pointers to C-language functions that implement the SQL function or
+** aggregate. ^A scalar SQL function requires an implementation of the xFunc
+** callback only; NULL pointers must be passed as the xStep and xFinal
+** parameters. ^An aggregate SQL function requires an implementation of xStep
+** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
+** SQL function or aggregate, pass NULL pointers for all three function
+** callbacks.
+**
+** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
+** and xInverse) passed to sqlite3_create_window_function are pointers to
+** C-language callbacks that implement the new function. xStep and xFinal
+** must both be non-NULL. xValue and xInverse may either both be NULL, in
+** which case a regular aggregate function is created, or must both be
+** non-NULL, in which case the new function may be used as either an aggregate
+** or aggregate window function. More details regarding the implementation
+** of aggregate window functions are
+** [user-defined window functions|available here].
+**
+** ^(If the final parameter to sqlite3_create_function_v2() or
+** sqlite3_create_window_function() is not NULL, then it is destructor for
+** the application data pointer. The destructor is invoked when the function
+** is deleted, either by being overloaded or when the database connection
+** closes.)^ ^The destructor is also invoked if the call to
+** sqlite3_create_function_v2() fails.  ^When the destructor callback is
+** invoked, it is passed a single argument which is a copy of the application
+** data pointer which was the fifth parameter to sqlite3_create_function_v2().
+**
+** ^It is permitted to register multiple implementations of the same
+** functions with the same name but with either differing numbers of
+** arguments or differing preferred text encodings.  ^SQLite will use
+** the implementation that most closely matches the way in which the
+** SQL function is used.  ^A function implementation with a non-negative
+** nArg parameter is a better match than a function implementation with
+** a negative nArg.  ^A function where the preferred text encoding
+** matches the database encoding is a better
+** match than a function where the encoding is different.
+** ^A function where the encoding difference is between UTF16le and UTF16be
+** is a closer match than a function where the encoding difference is
+** between UTF8 and UTF16.
+**
+** ^Built-in functions may be overloaded by new application-defined functions.
+**
+** ^An application-defined function is permitted to call other
+** SQLite interfaces.  However, such calls must not
+** close the database connection nor finalize or reset the prepared
+** statement in which the function is running.
+*/
+SQLITE_API int sqlite3_create_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+SQLITE_API int sqlite3_create_function16(
+  sqlite3 *db,
+  const void *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+SQLITE_API int sqlite3_create_function_v2(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void(*xDestroy)(void*)
+);
+SQLITE_API int sqlite3_create_window_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
+  void(*xDestroy)(void*)
+);
+
+/*
+** CAPI3REF: Text Encodings
+**
+** These constant define integer codes that represent the various
+** text encodings supported by SQLite.
+*/
+#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
+#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
+#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
+#define SQLITE_UTF16          4    /* Use native byte order */
+#define SQLITE_ANY            5    /* Deprecated */
+#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
+
+/*
+** CAPI3REF: Function Flags
+**
+** These constants may be ORed together with the
+** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
+** to [sqlite3_create_function()], [sqlite3_create_function16()], or
+** [sqlite3_create_function_v2()].
+**
+** <dl>
+** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
+** The SQLITE_DETERMINISTIC flag means that the new function always gives
+** the same output when the input parameters are the same.
+** The [abs|abs() function] is deterministic, for example, but
+** [randomblob|randomblob()] is not.  Functions must
+** be deterministic in order to be used in certain contexts such as
+** with the WHERE clause of [partial indexes] or in [generated columns].
+** SQLite might also optimize deterministic functions by factoring them
+** out of inner loops.
+** </dd>
+**
+** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
+** The SQLITE_DIRECTONLY flag means that the function may only be invoked
+** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
+** schema structures such as [CHECK constraints], [DEFAULT clauses],
+** [expression indexes], [partial indexes], or [generated columns].
+** <p>
+** The SQLITE_DIRECTONLY flag is recommended for any
+** [application-defined SQL function]
+** that has side-effects or that could potentially leak sensitive information.
+** This will prevent attacks in which an application is tricked
+** into using a database file that has had its schema surreptitiously
+** modified to invoke the application-defined function in ways that are
+** harmful.
+** <p>
+** Some people say it is good practice to set SQLITE_DIRECTONLY on all
+** [application-defined SQL functions], regardless of whether or not they
+** are security sensitive, as doing so prevents those functions from being used
+** inside of the database schema, and thus ensures that the database
+** can be inspected and modified using generic tools (such as the [CLI])
+** that do not have access to the application-defined functions.
+** </dd>
+**
+** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
+** The SQLITE_INNOCUOUS flag means that the function is unlikely
+** to cause problems even if misused.  An innocuous function should have
+** no side effects and should not depend on any values other than its
+** input parameters. The [abs|abs() function] is an example of an
+** innocuous function.
+** The [load_extension() SQL function] is not innocuous because of its
+** side effects.
+** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
+** exactly the same.  The [random|random() function] is an example of a
+** function that is innocuous but not deterministic.
+** <p>Some heightened security settings
+** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
+** disable the use of SQL functions inside views and triggers and in
+** schema structures such as [CHECK constraints], [DEFAULT clauses],
+** [expression indexes], [partial indexes], and [generated columns] unless
+** the function is tagged with SQLITE_INNOCUOUS.  Most built-in functions
+** are innocuous.  Developers are advised to avoid using the
+** SQLITE_INNOCUOUS flag for application-defined functions unless the
+** function has been carefully audited and found to be free of potentially
+** security-adverse side-effects and information-leaks.
+** </dd>
+**
+** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
+** The SQLITE_SUBTYPE flag indicates to SQLite that a function might call
+** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
+** This flag instructs SQLite to omit some corner-case optimizations that
+** might disrupt the operation of the [sqlite3_value_subtype()] function,
+** causing it to return zero rather than the correct subtype().
+** All SQL functions that invoke [sqlite3_value_subtype()] should have this
+** property.  If the SQLITE_SUBTYPE property is omitted, then the return
+** value from [sqlite3_value_subtype()] might sometimes be zero even though
+** a non-zero subtype was specified by the function argument expression.
+**
+** [[SQLITE_RESULT_SUBTYPE]] <dt>SQLITE_RESULT_SUBTYPE</dt><dd>
+** The SQLITE_RESULT_SUBTYPE flag indicates to SQLite that a function might call
+** [sqlite3_result_subtype()] to cause a sub-type to be associated with its
+** result.
+** Every function that invokes [sqlite3_result_subtype()] should have this
+** property.  If it does not, then the call to [sqlite3_result_subtype()]
+** might become a no-op if the function is used as term in an
+** [expression index].  On the other hand, SQL functions that never invoke
+** [sqlite3_result_subtype()] should avoid setting this property, as the
+** purpose of this property is to disable certain optimizations that are
+** incompatible with subtypes.
+**
+** [[SQLITE_SELFORDER1]] <dt>SQLITE_SELFORDER1</dt><dd>
+** The SQLITE_SELFORDER1 flag indicates that the function is an aggregate
+** that internally orders the values provided to the first argument.  The
+** ordered-set aggregate SQL notation with a single ORDER BY term can be
+** used to invoke this function.  If the ordered-set aggregate notation is
+** used on a function that lacks this flag, then an error is raised. Note
+** that the ordered-set aggregate syntax is only available if SQLite is
+** built using the -DSQLITE_ENABLE_ORDERED_SET_AGGREGATES compile-time option.
+** </dd>
+** </dl>
+*/
+#define SQLITE_DETERMINISTIC    0x000000800
+#define SQLITE_DIRECTONLY       0x000080000
+#define SQLITE_SUBTYPE          0x000100000
+#define SQLITE_INNOCUOUS        0x000200000
+#define SQLITE_RESULT_SUBTYPE   0x001000000
+#define SQLITE_SELFORDER1       0x002000000
+
+/*
+** CAPI3REF: Deprecated Functions
+** DEPRECATED
+**
+** These functions are [deprecated].  In order to maintain
+** backwards compatibility with older code, these functions continue
+** to be supported.  However, new applications should avoid
+** the use of these functions.  To encourage programmers to avoid
+** these functions, we will not explain what they do.
+*/
+#ifndef SQLITE_OMIT_DEPRECATED
+SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
+SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
+                      void*,sqlite3_int64);
+#endif
+
+/*
+** CAPI3REF: Obtaining SQL Values
+** METHOD: sqlite3_value
+**
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value
+** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value
+** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value
+** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value
+** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value
+** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value
+** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in
+** the native byteorder
+** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value
+** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value
+** <tr><td> <td> <td> 
+** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT in bytes
+** <tr><td><b>sqlite3_value_bytes16  </b>
+** <td>→  <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_value_type</b><td>→<td>Default
+** datatype of the value
+** <tr><td><b>sqlite3_value_numeric_type  </b>
+** <td>→  <td>Best numeric datatype of the value
+** <tr><td><b>sqlite3_value_nochange  </b>
+** <td>→  <td>True if the column is unchanged in an UPDATE
+** against a virtual table.
+** <tr><td><b>sqlite3_value_frombind  </b>
+** <td>→  <td>True if value originated from a [bound parameter]
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
+** These routines extract type, size, and content information from
+** [protected sqlite3_value] objects.  Protected sqlite3_value objects
+** are used to pass parameter information into the functions that
+** implement [application-defined SQL functions] and [virtual tables].
+**
+** These routines work only with [protected sqlite3_value] objects.
+** Any attempt to use these routines on an [unprotected sqlite3_value]
+** is not threadsafe.
+**
+** ^These routines work just like the corresponding [column access functions]
+** except that these routines take a single [protected sqlite3_value] object
+** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
+**
+** ^The sqlite3_value_text16() interface extracts a UTF-16 string
+** in the native byte-order of the host machine.  ^The
+** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
+** extract UTF-16 strings as big-endian and little-endian respectively.
+**
+** ^If [sqlite3_value] object V was initialized
+** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
+** and if X and Y are strings that compare equal according to strcmp(X,Y),
+** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
+** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
+** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
+**
+** ^(The sqlite3_value_type(V) interface returns the
+** [SQLITE_INTEGER | datatype code] for the initial datatype of the
+** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
+** Other interfaces might change the datatype for an sqlite3_value object.
+** For example, if the datatype is initially SQLITE_INTEGER and
+** sqlite3_value_text(V) is called to extract a text value for that
+** integer, then subsequent calls to sqlite3_value_type(V) might return
+** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
+** occurs is undefined and may change from one release of SQLite to the next.
+**
+** ^(The sqlite3_value_numeric_type() interface attempts to apply
+** numeric affinity to the value.  This means that an attempt is
+** made to convert the value to an integer or floating point.  If
+** such a conversion is possible without loss of information (in other
+** words, if the value is a string that looks like a number)
+** then the conversion is performed.  Otherwise no conversion occurs.
+** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
+**
+** ^Within the [xUpdate] method of a [virtual table], the
+** sqlite3_value_nochange(X) interface returns true if and only if
+** the column corresponding to X is unchanged by the UPDATE operation
+** that the xUpdate method call was invoked to implement and if
+** and the prior [xColumn] method call that was invoked to extracted
+** the value for that column returned without setting a result (probably
+** because it queried [sqlite3_vtab_nochange()] and found that the column
+** was unchanging).  ^Within an [xUpdate] method, any value for which
+** sqlite3_value_nochange(X) is true will in all other respects appear
+** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
+** than within an [xUpdate] method call for an UPDATE statement, then
+** the return value is arbitrary and meaningless.
+**
+** ^The sqlite3_value_frombind(X) interface returns non-zero if the
+** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
+** interfaces.  ^If X comes from an SQL literal value, or a table column,
+** or an expression, then sqlite3_value_frombind(X) returns zero.
+**
+** Please pay particular attention to the fact that the pointer returned
+** from [sqlite3_value_blob()], [sqlite3_value_text()], or
+** [sqlite3_value_text16()] can be invalidated by a subsequent call to
+** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
+** or [sqlite3_value_text16()].
+**
+** These routines must be called from the same thread as
+** the SQL function that supplied the [sqlite3_value*] parameters.
+**
+** As long as the input parameter is correct, these routines can only
+** fail if an out-of-memory error occurs during a format conversion.
+** Only the following subset of interfaces are subject to out-of-memory
+** errors:
+**
+** <ul>
+** <li> sqlite3_value_blob()
+** <li> sqlite3_value_text()
+** <li> sqlite3_value_text16()
+** <li> sqlite3_value_text16le()
+** <li> sqlite3_value_text16be()
+** <li> sqlite3_value_bytes()
+** <li> sqlite3_value_bytes16()
+** </ul>
+**
+** If an out-of-memory error occurs, then the return value from these
+** routines is the same as if the column had contained an SQL NULL value.
+** Valid SQL NULL returns can be distinguished from out-of-memory errors
+** by invoking the [sqlite3_errcode()] immediately after the suspect
+** return value is obtained and before any
+** other SQLite interface is called on the same [database connection].
+*/
+SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
+SQLITE_API double sqlite3_value_double(sqlite3_value*);
+SQLITE_API int sqlite3_value_int(sqlite3_value*);
+SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
+SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
+SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
+SQLITE_API int sqlite3_value_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
+SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
+
+/*
+** CAPI3REF: Report the internal text encoding state of an sqlite3_value object
+** METHOD: sqlite3_value
+**
+** ^(The sqlite3_value_encoding(X) interface returns one of [SQLITE_UTF8],
+** [SQLITE_UTF16BE], or [SQLITE_UTF16LE] according to the current text encoding
+** of the value X, assuming that X has type TEXT.)^  If sqlite3_value_type(X)
+** returns something other than SQLITE_TEXT, then the return value from
+** sqlite3_value_encoding(X) is meaningless.  ^Calls to
+** [sqlite3_value_text(X)], [sqlite3_value_text16(X)], [sqlite3_value_text16be(X)],
+** [sqlite3_value_text16le(X)], [sqlite3_value_bytes(X)], or
+** [sqlite3_value_bytes16(X)] might change the encoding of the value X and
+** thus change the return from subsequent calls to sqlite3_value_encoding(X).
+**
+** This routine is intended for used by applications that test and validate
+** the SQLite implementation.  This routine is inquiring about the opaque
+** internal state of an [sqlite3_value] object.  Ordinary applications should
+** not need to know what the internal state of an sqlite3_value object is and
+** hence should not need to use this interface.
+*/
+SQLITE_API int sqlite3_value_encoding(sqlite3_value*);
+
+/*
+** CAPI3REF: Finding The Subtype Of SQL Values
+** METHOD: sqlite3_value
+**
+** The sqlite3_value_subtype(V) function returns the subtype for
+** an [application-defined SQL function] argument V.  The subtype
+** information can be used to pass a limited amount of context from
+** one SQL function to another.  Use the [sqlite3_result_subtype()]
+** routine to set the subtype for the return value of an SQL function.
+**
+** Every [application-defined SQL function] that invokes this interface
+** should include the [SQLITE_SUBTYPE] property in the text
+** encoding argument when the function is [sqlite3_create_function|registered].
+** If the [SQLITE_SUBTYPE] property is omitted, then sqlite3_value_subtype()
+** might return zero instead of the upstream subtype in some corner cases.
+*/
+SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
+
+/*
+** CAPI3REF: Copy And Free SQL Values
+** METHOD: sqlite3_value
+**
+** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
+** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
+** is a [protected sqlite3_value] object even if the input is not.
+** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
+** memory allocation fails. ^If V is a [pointer value], then the result
+** of sqlite3_value_dup(V) is a NULL value.
+**
+** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
+** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
+** then sqlite3_value_free(V) is a harmless no-op.
+*/
+SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
+SQLITE_API void sqlite3_value_free(sqlite3_value*);
+
+/*
+** CAPI3REF: Obtain Aggregate Function Context
+** METHOD: sqlite3_context
+**
+** Implementations of aggregate SQL functions use this
+** routine to allocate memory for storing their state.
+**
+** ^The first time the sqlite3_aggregate_context(C,N) routine is called
+** for a particular aggregate function, SQLite allocates
+** N bytes of memory, zeroes out that memory, and returns a pointer
+** to the new memory. ^On second and subsequent calls to
+** sqlite3_aggregate_context() for the same aggregate function instance,
+** the same buffer is returned.  Sqlite3_aggregate_context() is normally
+** called once for each invocation of the xStep callback and then one
+** last time when the xFinal callback is invoked.  ^(When no rows match
+** an aggregate query, the xStep() callback of the aggregate function
+** implementation is never called and xFinal() is called exactly once.
+** In those cases, sqlite3_aggregate_context() might be called for the
+** first time from within xFinal().)^
+**
+** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
+** when first called if N is less than or equal to zero or if a memory
+** allocation error occurs.
+**
+** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
+** determined by the N parameter on first successful call.  Changing the
+** value of N in any subsequent call to sqlite3_aggregate_context() within
+** the same aggregate function instance will not resize the memory
+** allocation.)^  Within the xFinal callback, it is customary to set
+** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
+** pointless memory allocations occur.
+**
+** ^SQLite automatically frees the memory allocated by
+** sqlite3_aggregate_context() when the aggregate query concludes.
+**
+** The first parameter must be a copy of the
+** [sqlite3_context | SQL function context] that is the first parameter
+** to the xStep or xFinal callback routine that implements the aggregate
+** function.
+**
+** This routine must be called from the same thread in which
+** the aggregate SQL function is running.
+*/
+SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
+
+/*
+** CAPI3REF: User Data For Functions
+** METHOD: sqlite3_context
+**
+** ^The sqlite3_user_data() interface returns a copy of
+** the pointer that was the pUserData parameter (the 5th parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+**
+** This routine must be called from the same thread in which
+** the application-defined function is running.
+*/
+SQLITE_API void *sqlite3_user_data(sqlite3_context*);
+
+/*
+** CAPI3REF: Database Connection For Functions
+** METHOD: sqlite3_context
+**
+** ^The sqlite3_context_db_handle() interface returns a copy of
+** the pointer to the [database connection] (the 1st parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+*/
+SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
+
+/*
+** CAPI3REF: Function Auxiliary Data
+** METHOD: sqlite3_context
+**
+** These functions may be used by (non-aggregate) SQL functions to
+** associate auxiliary data with argument values. If the same argument
+** value is passed to multiple invocations of the same SQL function during
+** query execution, under some circumstances the associated auxiliary data
+** might be preserved.  An example of where this might be useful is in a
+** regular-expression matching function. The compiled version of the regular
+** expression can be stored as auxiliary data associated with the pattern string.
+** Then as long as the pattern string remains the same,
+** the compiled regular expression can be reused on multiple
+** invocations of the same function.
+**
+** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the auxiliary data
+** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
+** value to the application-defined function.  ^N is zero for the left-most
+** function argument.  ^If there is no auxiliary data
+** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
+** returns a NULL pointer.
+**
+** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as auxiliary data for the
+** N-th argument of the application-defined function.  ^Subsequent
+** calls to sqlite3_get_auxdata(C,N) return P from the most recent
+** sqlite3_set_auxdata(C,N,P,X) call if the auxiliary data is still valid or
+** NULL if the auxiliary data has been discarded.
+** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
+** SQLite will invoke the destructor function X with parameter P exactly
+** once, when the auxiliary data is discarded.
+** SQLite is free to discard the auxiliary data at any time, including: <ul>
+** <li> ^(when the corresponding function parameter changes)^, or
+** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
+**      SQL statement)^, or
+** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
+**       parameter)^, or
+** <li> ^(during the original sqlite3_set_auxdata() call when a memory
+**      allocation error occurs.)^
+** <li> ^(during the original sqlite3_set_auxdata() call if the function
+**      is evaluated during query planning instead of during query execution,
+**      as sometimes happens with [SQLITE_ENABLE_STAT4].)^ </ul>
+**
+** Note the last two bullets in particular.  The destructor X in
+** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
+** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
+** should be called near the end of the function implementation and the
+** function implementation should not make any use of P after
+** sqlite3_set_auxdata() has been called.  Furthermore, a call to
+** sqlite3_get_auxdata() that occurs immediately after a corresponding call
+** to sqlite3_set_auxdata() might still return NULL if an out-of-memory
+** condition occurred during the sqlite3_set_auxdata() call or if the
+** function is being evaluated during query planning rather than during
+** query execution.
+**
+** ^(In practice, auxiliary data is preserved between function calls for
+** function parameters that are compile-time constants, including literal
+** values and [parameters] and expressions composed from the same.)^
+**
+** The value of the N parameter to these interfaces should be non-negative.
+** Future enhancements may make use of negative N values to define new
+** kinds of function caching behavior.
+**
+** These routines must be called from the same thread in which
+** the SQL function is running.
+**
+** See also: [sqlite3_get_clientdata()] and [sqlite3_set_clientdata()].
+*/
+SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
+SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
+
+/*
+** CAPI3REF: Database Connection Client Data
+** METHOD: sqlite3
+**
+** These functions are used to associate one or more named pointers
+** with a [database connection].
+** A call to sqlite3_set_clientdata(D,N,P,X) causes the pointer P
+** to be attached to [database connection] D using name N.  Subsequent
+** calls to sqlite3_get_clientdata(D,N) will return a copy of pointer P
+** or a NULL pointer if there were no prior calls to
+** sqlite3_set_clientdata() with the same values of D and N.
+** Names are compared using strcmp() and are thus case sensitive.
+**
+** If P and X are both non-NULL, then the destructor X is invoked with
+** argument P on the first of the following occurrences:
+** <ul>
+** <li> An out-of-memory error occurs during the call to
+**      sqlite3_set_clientdata() which attempts to register pointer P.
+** <li> A subsequent call to sqlite3_set_clientdata(D,N,P,X) is made
+**      with the same D and N parameters.
+** <li> The database connection closes.  SQLite does not make any guarantees
+**      about the order in which destructors are called, only that all
+**      destructors will be called exactly once at some point during the
+**      database connection closing process.
+** </ul>
+**
+** SQLite does not do anything with client data other than invoke
+** destructors on the client data at the appropriate time.  The intended
+** use for client data is to provide a mechanism for wrapper libraries
+** to store additional information about an SQLite database connection.
+**
+** There is no limit (other than available memory) on the number of different
+** client data pointers (with different names) that can be attached to a
+** single database connection.  However, the implementation is optimized
+** for the case of having only one or two different client data names.
+** Applications and wrapper libraries are discouraged from using more than
+** one client data name each.
+**
+** There is no way to enumerate the client data pointers
+** associated with a database connection.  The N parameter can be thought
+** of as a secret key such that only code that knows the secret key is able
+** to access the associated data.
+**
+** Security Warning:  These interfaces should not be exposed in scripting
+** languages or in other circumstances where it might be possible for an
+** an attacker to invoke them.  Any agent that can invoke these interfaces
+** can probably also take control of the process.
+**
+** Database connection client data is only available for SQLite
+** version 3.44.0 ([dateof:3.44.0]) and later.
+**
+** See also: [sqlite3_set_auxdata()] and [sqlite3_get_auxdata()].
+*/
+SQLITE_API void *sqlite3_get_clientdata(sqlite3*,const char*);
+SQLITE_API int sqlite3_set_clientdata(sqlite3*, const char*, void*, void(*)(void*));
+
+/*
+** CAPI3REF: Constants Defining Special Destructor Behavior
+**
+** These are special values for the destructor that is passed in as the
+** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
+** argument is SQLITE_STATIC, it means that the content pointer is constant
+** and will never change.  It does not need to be destroyed.  ^The
+** SQLITE_TRANSIENT value means that the content will likely change in
+** the near future and that SQLite should make its own private copy of
+** the content before returning.
+**
+** The typedef is necessary to work around problems in certain
+** C++ compilers.
+*/
+typedef void (*sqlite3_destructor_type)(void*);
+#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
+#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
+
+/*
+** CAPI3REF: Setting The Result Of An SQL Function
+** METHOD: sqlite3_context
+**
+** These routines are used by the xFunc or xFinal callbacks that
+** implement SQL functions and aggregates.  See
+** [sqlite3_create_function()] and [sqlite3_create_function16()]
+** for additional information.
+**
+** These functions work very much like the [parameter binding] family of
+** functions used to bind values to host parameters in prepared statements.
+** Refer to the [SQL parameter] documentation for additional information.
+**
+** ^The sqlite3_result_blob() interface sets the result from
+** an application-defined function to be the BLOB whose content is pointed
+** to by the second parameter and which is N bytes long where N is the
+** third parameter.
+**
+** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
+** interfaces set the result of the application-defined function to be
+** a BLOB containing all zero bytes and N bytes in size.
+**
+** ^The sqlite3_result_double() interface sets the result from
+** an application-defined function to be a floating point value specified
+** by its 2nd argument.
+**
+** ^The sqlite3_result_error() and sqlite3_result_error16() functions
+** cause the implemented SQL function to throw an exception.
+** ^SQLite uses the string pointed to by the
+** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
+** as the text of an error message.  ^SQLite interprets the error
+** message string from sqlite3_result_error() as UTF-8. ^SQLite
+** interprets the string from sqlite3_result_error16() as UTF-16 using
+** the same [byte-order determination rules] as [sqlite3_bind_text16()].
+** ^If the third parameter to sqlite3_result_error()
+** or sqlite3_result_error16() is negative then SQLite takes as the error
+** message all text up through the first zero character.
+** ^If the third parameter to sqlite3_result_error() or
+** sqlite3_result_error16() is non-negative then SQLite takes that many
+** bytes (not characters) from the 2nd parameter as the error message.
+** ^The sqlite3_result_error() and sqlite3_result_error16()
+** routines make a private copy of the error message text before
+** they return.  Hence, the calling function can deallocate or
+** modify the text after they return without harm.
+** ^The sqlite3_result_error_code() function changes the error code
+** returned by SQLite as a result of an error in a function.  ^By default,
+** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
+** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
+**
+** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
+** error indicating that a string or BLOB is too long to represent.
+**
+** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
+** error indicating that a memory allocation failed.
+**
+** ^The sqlite3_result_int() interface sets the return value
+** of the application-defined function to be the 32-bit signed integer
+** value given in the 2nd argument.
+** ^The sqlite3_result_int64() interface sets the return value
+** of the application-defined function to be the 64-bit signed integer
+** value given in the 2nd argument.
+**
+** ^The sqlite3_result_null() interface sets the return value
+** of the application-defined function to be NULL.
+**
+** ^The sqlite3_result_text(), sqlite3_result_text16(),
+** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
+** set the return value of the application-defined function to be
+** a text string which is represented as UTF-8, UTF-16 native byte order,
+** UTF-16 little endian, or UTF-16 big endian, respectively.
+** ^The sqlite3_result_text64() interface sets the return value of an
+** application-defined function to be a text string in an encoding
+** specified by the fifth (and last) parameter, which must be one
+** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
+** ^SQLite takes the text result from the application from
+** the 2nd parameter of the sqlite3_result_text* interfaces.
+** ^If the 3rd parameter to any of the sqlite3_result_text* interfaces
+** other than sqlite3_result_text64() is negative, then SQLite computes
+** the string length itself by searching the 2nd parameter for the first
+** zero character.
+** ^If the 3rd parameter to the sqlite3_result_text* interfaces
+** is non-negative, then as many bytes (not characters) of the text
+** pointed to by the 2nd parameter are taken as the application-defined
+** function result.  If the 3rd parameter is non-negative, then it
+** must be the byte offset into the string where the NUL terminator would
+** appear if the string where NUL terminated.  If any NUL characters occur
+** in the string at a byte offset that is less than the value of the 3rd
+** parameter, then the resulting string will contain embedded NULs and the
+** result of expressions operating on strings with embedded NULs is undefined.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
+** function as the destructor on the text or BLOB result when it has
+** finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
+** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
+** assumes that the text or BLOB result is in constant space and does not
+** copy the content of the parameter nor call a destructor on the content
+** when it has finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
+** then SQLite makes a copy of the result into space obtained
+** from [sqlite3_malloc()] before it returns.
+**
+** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
+** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
+** when the encoding is not UTF8, if the input UTF16 begins with a
+** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
+** string and the rest of the string is interpreted according to the
+** byte-order specified by the BOM.  ^The byte-order specified by
+** the BOM at the beginning of the text overrides the byte-order
+** specified by the interface procedure.  ^So, for example, if
+** sqlite3_result_text16le() is invoked with text that begins
+** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
+** first two bytes of input are skipped and the remaining input
+** is interpreted as UTF16BE text.
+**
+** ^For UTF16 input text to the sqlite3_result_text16(),
+** sqlite3_result_text16be(), sqlite3_result_text16le(), and
+** sqlite3_result_text64() routines, if the text contains invalid
+** UTF16 characters, the invalid characters might be converted
+** into the unicode replacement character, U+FFFD.
+**
+** ^The sqlite3_result_value() interface sets the result of
+** the application-defined function to be a copy of the
+** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
+** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
+** so that the [sqlite3_value] specified in the parameter may change or
+** be deallocated after sqlite3_result_value() returns without harm.
+** ^A [protected sqlite3_value] object may always be used where an
+** [unprotected sqlite3_value] object is required, so either
+** kind of [sqlite3_value] object can be used with this interface.
+**
+** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
+** SQL NULL value, just like [sqlite3_result_null(C)], except that it
+** also associates the host-language pointer P or type T with that
+** NULL value such that the pointer can be retrieved within an
+** [application-defined SQL function] using [sqlite3_value_pointer()].
+** ^If the D parameter is not NULL, then it is a pointer to a destructor
+** for the P parameter.  ^SQLite invokes D with P as its only argument
+** when SQLite is finished with P.  The T parameter should be a static
+** string and preferably a string literal. The sqlite3_result_pointer()
+** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
+**
+** If these routines are called from within the different thread
+** than the one containing the application-defined function that received
+** the [sqlite3_context] pointer, the results are undefined.
+*/
+SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
+                           sqlite3_uint64,void(*)(void*));
+SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
+SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
+SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
+SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
+SQLITE_API void sqlite3_result_null(sqlite3_context*);
+SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
+                           void(*)(void*), unsigned char encoding);
+SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
+SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
+SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
+SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
+
+
+/*
+** CAPI3REF: Setting The Subtype Of An SQL Function
+** METHOD: sqlite3_context
+**
+** The sqlite3_result_subtype(C,T) function causes the subtype of
+** the result from the [application-defined SQL function] with
+** [sqlite3_context] C to be the value T.  Only the lower 8 bits
+** of the subtype T are preserved in current versions of SQLite;
+** higher order bits are discarded.
+** The number of subtype bytes preserved by SQLite might increase
+** in future releases of SQLite.
+**
+** Every [application-defined SQL function] that invokes this interface
+** should include the [SQLITE_RESULT_SUBTYPE] property in its
+** text encoding argument when the SQL function is
+** [sqlite3_create_function|registered].  If the [SQLITE_RESULT_SUBTYPE]
+** property is omitted from the function that invokes sqlite3_result_subtype(),
+** then in some cases the sqlite3_result_subtype() might fail to set
+** the result subtype.
+**
+** If SQLite is compiled with -DSQLITE_STRICT_SUBTYPE=1, then any
+** SQL function that invokes the sqlite3_result_subtype() interface
+** and that does not have the SQLITE_RESULT_SUBTYPE property will raise
+** an error.  Future versions of SQLite might enable -DSQLITE_STRICT_SUBTYPE=1
+** by default.
+*/
+SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
+
+/*
+** CAPI3REF: Define New Collating Sequences
+** METHOD: sqlite3
+**
+** ^These functions add, remove, or modify a [collation] associated
+** with the [database connection] specified as the first argument.
+**
+** ^The name of the collation is a UTF-8 string
+** for sqlite3_create_collation() and sqlite3_create_collation_v2()
+** and a UTF-16 string in native byte order for sqlite3_create_collation16().
+** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
+** considered to be the same name.
+**
+** ^(The third argument (eTextRep) must be one of the constants:
+** <ul>
+** <li> [SQLITE_UTF8],
+** <li> [SQLITE_UTF16LE],
+** <li> [SQLITE_UTF16BE],
+** <li> [SQLITE_UTF16], or
+** <li> [SQLITE_UTF16_ALIGNED].
+** </ul>)^
+** ^The eTextRep argument determines the encoding of strings passed
+** to the collating function callback, xCompare.
+** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
+** force strings to be UTF16 with native byte order.
+** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
+** on an even byte address.
+**
+** ^The fourth argument, pArg, is an application data pointer that is passed
+** through as the first argument to the collating function callback.
+**
+** ^The fifth argument, xCompare, is a pointer to the collating function.
+** ^Multiple collating functions can be registered using the same name but
+** with different eTextRep parameters and SQLite will use whichever
+** function requires the least amount of data transformation.
+** ^If the xCompare argument is NULL then the collating function is
+** deleted.  ^When all collating functions having the same name are deleted,
+** that collation is no longer usable.
+**
+** ^The collating function callback is invoked with a copy of the pArg
+** application data pointer and with two strings in the encoding specified
+** by the eTextRep argument.  The two integer parameters to the collating
+** function callback are the length of the two strings, in bytes. The collating
+** function must return an integer that is negative, zero, or positive
+** if the first string is less than, equal to, or greater than the second,
+** respectively.  A collating function must always return the same answer
+** given the same inputs.  If two or more collating functions are registered
+** to the same collation name (using different eTextRep values) then all
+** must give an equivalent answer when invoked with equivalent strings.
+** The collating function must obey the following properties for all
+** strings A, B, and C:
+**
+** <ol>
+** <li> If A==B then B==A.
+** <li> If A==B and B==C then A==C.
+** <li> If A<B THEN B>A.
+** <li> If A<B and B<C then A<C.
+** </ol>
+**
+** If a collating function fails any of the above constraints and that
+** collating function is registered and used, then the behavior of SQLite
+** is undefined.
+**
+** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
+** with the addition that the xDestroy callback is invoked on pArg when
+** the collating function is deleted.
+** ^Collating functions are deleted when they are overridden by later
+** calls to the collation creation functions or when the
+** [database connection] is closed using [sqlite3_close()].
+**
+** ^The xDestroy callback is <u>not</u> called if the
+** sqlite3_create_collation_v2() function fails.  Applications that invoke
+** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
+** check the return code and dispose of the application data pointer
+** themselves rather than expecting SQLite to deal with it for them.
+** This is different from every other SQLite interface.  The inconsistency
+** is unfortunate but cannot be changed without breaking backwards
+** compatibility.
+**
+** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
+*/
+SQLITE_API int sqlite3_create_collation(
+  sqlite3*,
+  const char *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+SQLITE_API int sqlite3_create_collation_v2(
+  sqlite3*,
+  const char *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDestroy)(void*)
+);
+SQLITE_API int sqlite3_create_collation16(
+  sqlite3*,
+  const void *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+
+/*
+** CAPI3REF: Collation Needed Callbacks
+** METHOD: sqlite3
+**
+** ^To avoid having to register all collation sequences before a database
+** can be used, a single callback function may be registered with the
+** [database connection] to be invoked whenever an undefined collation
+** sequence is required.
+**
+** ^If the function is registered using the sqlite3_collation_needed() API,
+** then it is passed the names of undefined collation sequences as strings
+** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
+** the names are passed as UTF-16 in machine native byte order.
+** ^A call to either function replaces the existing collation-needed callback.
+**
+** ^(When the callback is invoked, the first argument passed is a copy
+** of the second argument to sqlite3_collation_needed() or
+** sqlite3_collation_needed16().  The second argument is the database
+** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
+** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
+** sequence function required.  The fourth parameter is the name of the
+** required collation sequence.)^
+**
+** The callback function should register the desired collation using
+** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
+** [sqlite3_create_collation_v2()].
+*/
+SQLITE_API int sqlite3_collation_needed(
+  sqlite3*,
+  void*,
+  void(*)(void*,sqlite3*,int eTextRep,const char*)
+);
+SQLITE_API int sqlite3_collation_needed16(
+  sqlite3*,
+  void*,
+  void(*)(void*,sqlite3*,int eTextRep,const void*)
+);
+
+#ifdef SQLITE_ENABLE_CEROD
+/*
+** Specify the activation key for a CEROD database.  Unless
+** activated, none of the CEROD routines will work.
+*/
+SQLITE_API void sqlite3_activate_cerod(
+  const char *zPassPhrase        /* Activation phrase */
+);
+#endif
+
+/*
+** CAPI3REF: Suspend Execution For A Short Time
+**
+** The sqlite3_sleep() function causes the current thread to suspend execution
+** for at least a number of milliseconds specified in its parameter.
+**
+** If the operating system does not support sleep requests with
+** millisecond time resolution, then the time will be rounded up to
+** the nearest second. The number of milliseconds of sleep actually
+** requested from the operating system is returned.
+**
+** ^SQLite implements this interface by calling the xSleep()
+** method of the default [sqlite3_vfs] object.  If the xSleep() method
+** of the default VFS is not implemented correctly, or not implemented at
+** all, then the behavior of sqlite3_sleep() may deviate from the description
+** in the previous paragraphs.
+**
+** If a negative argument is passed to sqlite3_sleep() the results vary by
+** VFS and operating system.  Some system treat a negative argument as an
+** instruction to sleep forever.  Others understand it to mean do not sleep
+** at all. ^In SQLite version 3.42.0 and later, a negative
+** argument passed into sqlite3_sleep() is changed to zero before it is relayed
+** down into the xSleep method of the VFS.
+*/
+SQLITE_API int sqlite3_sleep(int);
+
+/*
+** CAPI3REF: Name Of The Folder Holding Temporary Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all temporary files
+** created by SQLite when using a built-in [sqlite3_vfs | VFS]
+** will be placed in that directory.)^  ^If this variable
+** is a NULL pointer, then SQLite performs a search for an appropriate
+** temporary file directory.
+**
+** Applications are strongly discouraged from using this global variable.
+** It is required to set a temporary folder on Windows Runtime (WinRT).
+** But for all other platforms, it is highly recommended that applications
+** neither read nor write this variable.  This global variable is a relic
+** that exists for backwards compatibility of legacy applications and should
+** be avoided in new projects.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [temp_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [temp_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [temp_store_directory pragma] should be avoided.
+** Except when requested by the [temp_store_directory pragma], SQLite
+** does not free the memory that sqlite3_temp_directory points to.  If
+** the application wants that memory to be freed, it must do
+** so itself, taking care to only do so after all [database connection]
+** objects have been destroyed.
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
+** features that require the use of temporary files may fail.  Here is an
+** example of how to do this using C++ with the Windows Runtime:
+**
+** <blockquote><pre>
+** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
+**       TemporaryFolder->Path->Data();
+** char zPathBuf[MAX_PATH + 1];
+** memset(zPathBuf, 0, sizeof(zPathBuf));
+** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
+**       NULL, NULL);
+** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
+** </pre></blockquote>
+*/
+SQLITE_API char *sqlite3_temp_directory;
+
+/*
+** CAPI3REF: Name Of The Folder Holding Database Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all database files
+** specified with a relative pathname and created or accessed by
+** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
+** to be relative to that directory.)^ ^If this variable is a NULL
+** pointer, then SQLite assumes that all database files specified
+** with a relative pathname are relative to the current directory
+** for the process.  Only the windows VFS makes use of this global
+** variable; it is ignored by the unix VFS.
+**
+** Changing the value of this variable while a database connection is
+** open can result in a corrupt database.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [data_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [data_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [data_store_directory pragma] should be avoided.
+*/
+SQLITE_API char *sqlite3_data_directory;
+
+/*
+** CAPI3REF: Win32 Specific Interface
+**
+** These interfaces are available only on Windows.  The
+** [sqlite3_win32_set_directory] interface is used to set the value associated
+** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
+** zValue, depending on the value of the type parameter.  The zValue parameter
+** should be NULL to cause the previous value to be freed via [sqlite3_free];
+** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
+** prior to being used.  The [sqlite3_win32_set_directory] interface returns
+** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
+** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
+** [sqlite3_data_directory] variable is intended to act as a replacement for
+** the current directory on the sub-platforms of Win32 where that concept is
+** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
+** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
+** sqlite3_win32_set_directory interface except the string parameter must be
+** UTF-8 or UTF-16, respectively.
+*/
+SQLITE_API int sqlite3_win32_set_directory(
+  unsigned long type, /* Identifier for directory being set or reset */
+  void *zValue        /* New value for directory being set or reset */
+);
+SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
+SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
+
+/*
+** CAPI3REF: Win32 Directory Types
+**
+** These macros are only available on Windows.  They define the allowed values
+** for the type argument to the [sqlite3_win32_set_directory] interface.
+*/
+#define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
+#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
+
+/*
+** CAPI3REF: Test For Auto-Commit Mode
+** KEYWORDS: {autocommit mode}
+** METHOD: sqlite3
+**
+** ^The sqlite3_get_autocommit() interface returns non-zero or
+** zero if the given database connection is or is not in autocommit mode,
+** respectively.  ^Autocommit mode is on by default.
+** ^Autocommit mode is disabled by a [BEGIN] statement.
+** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
+**
+** If certain kinds of errors occur on a statement within a multi-statement
+** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
+** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
+** transaction might be rolled back automatically.  The only way to
+** find out whether SQLite automatically rolled back the transaction after
+** an error is to use this function.
+**
+** If another thread changes the autocommit status of the database
+** connection while this routine is running, then the return value
+** is undefined.
+*/
+SQLITE_API int sqlite3_get_autocommit(sqlite3*);
+
+/*
+** CAPI3REF: Find The Database Handle Of A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_db_handle interface returns the [database connection] handle
+** to which a [prepared statement] belongs.  ^The [database connection]
+** returned by sqlite3_db_handle is the same [database connection]
+** that was the first argument
+** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
+** create the statement in the first place.
+*/
+SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Return The Schema Name For A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
+** for the N-th database on database connection D, or a NULL pointer of N is
+** out of range.  An N value of 0 means the main database file.  An N of 1 is
+** the "temp" schema.  Larger values of N correspond to various ATTACH-ed
+** databases.
+**
+** Space to hold the string that is returned by sqlite3_db_name() is managed
+** by SQLite itself.  The string might be deallocated by any operation that
+** changes the schema, including [ATTACH] or [DETACH] or calls to
+** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
+** occur on a different thread.  Applications that need to
+** remember the string long-term should make their own copy.  Applications that
+** are accessing the same database connection simultaneously on multiple
+** threads should mutex-protect calls to this API and should make their own
+** private copy of the result prior to releasing the mutex.
+*/
+SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Return The Filename For A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
+** associated with database N of connection D.
+** ^If there is no attached database N on the database
+** connection D, or if database N is a temporary or in-memory database, then
+** this function will return either a NULL pointer or an empty string.
+**
+** ^The string value returned by this routine is owned and managed by
+** the database connection.  ^The value will be valid until the database N
+** is [DETACH]-ed or until the database connection closes.
+**
+** ^The filename returned by this function is the output of the
+** xFullPathname method of the [VFS].  ^In other words, the filename
+** will be an absolute pathname, even if the filename used
+** to open the database originally was a URI or relative pathname.
+**
+** If the filename pointer returned by this routine is not NULL, then it
+** can be used as the filename input parameter to these routines:
+** <ul>
+** <li> [sqlite3_uri_parameter()]
+** <li> [sqlite3_uri_boolean()]
+** <li> [sqlite3_uri_int64()]
+** <li> [sqlite3_filename_database()]
+** <li> [sqlite3_filename_journal()]
+** <li> [sqlite3_filename_wal()]
+** </ul>
+*/
+SQLITE_API sqlite3_filename sqlite3_db_filename(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine if a database is read-only
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
+** of connection D is read-only, 0 if it is read/write, or -1 if N is not
+** the name of a database on connection D.
+*/
+SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine the transaction state of a database
+** METHOD: sqlite3
+**
+** ^The sqlite3_txn_state(D,S) interface returns the current
+** [transaction state] of schema S in database connection D.  ^If S is NULL,
+** then the highest transaction state of any schema on database connection D
+** is returned.  Transaction states are (in order of lowest to highest):
+** <ol>
+** <li value="0"> SQLITE_TXN_NONE
+** <li value="1"> SQLITE_TXN_READ
+** <li value="2"> SQLITE_TXN_WRITE
+** </ol>
+** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
+** a valid schema, then -1 is returned.
+*/
+SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
+
+/*
+** CAPI3REF: Allowed return values from sqlite3_txn_state()
+** KEYWORDS: {transaction state}
+**
+** These constants define the current transaction state of a database file.
+** ^The [sqlite3_txn_state(D,S)] interface returns one of these
+** constants in order to describe the transaction state of schema S
+** in [database connection] D.
+**
+** <dl>
+** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
+** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
+** pending.</dd>
+**
+** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
+** <dd>The SQLITE_TXN_READ state means that the database is currently
+** in a read transaction.  Content has been read from the database file
+** but nothing in the database file has changed.  The transaction state
+** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
+** no other conflicting concurrent write transactions.  The transaction
+** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
+** [COMMIT].</dd>
+**
+** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
+** <dd>The SQLITE_TXN_WRITE state means that the database is currently
+** in a write transaction.  Content has been written to the database file
+** but has not yet committed.  The transaction state will change to
+** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
+*/
+#define SQLITE_TXN_NONE  0
+#define SQLITE_TXN_READ  1
+#define SQLITE_TXN_WRITE 2
+
+/*
+** CAPI3REF: Find the next prepared statement
+** METHOD: sqlite3
+**
+** ^This interface returns a pointer to the next [prepared statement] after
+** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
+** then this interface returns a pointer to the first prepared statement
+** associated with the database connection pDb.  ^If no prepared statement
+** satisfies the conditions of this routine, it returns NULL.
+**
+** The [database connection] pointer D in a call to
+** [sqlite3_next_stmt(D,S)] must refer to an open database
+** connection and in particular must not be a NULL pointer.
+*/
+SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Commit And Rollback Notification Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_commit_hook() interface registers a callback
+** function to be invoked whenever a transaction is [COMMIT | committed].
+** ^Any callback set by a previous call to sqlite3_commit_hook()
+** for the same database connection is overridden.
+** ^The sqlite3_rollback_hook() interface registers a callback
+** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
+** ^Any callback set by a previous call to sqlite3_rollback_hook()
+** for the same database connection is overridden.
+** ^The pArg argument is passed through to the callback.
+** ^If the callback on a commit hook function returns non-zero,
+** then the commit is converted into a rollback.
+**
+** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
+** return the P argument from the previous call of the same function
+** on the same [database connection] D, or NULL for
+** the first call for each function on D.
+**
+** The commit and rollback hook callbacks are not reentrant.
+** The callback implementation must not do anything that will modify
+** the database connection that invoked the callback.  Any actions
+** to modify the database connection must be deferred until after the
+** completion of the [sqlite3_step()] call that triggered the commit
+** or rollback hook in the first place.
+** Note that running any other SQL statements, including SELECT statements,
+** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
+** the database connections for the meaning of "modify" in this paragraph.
+**
+** ^Registering a NULL function disables the callback.
+**
+** ^When the commit hook callback routine returns zero, the [COMMIT]
+** operation is allowed to continue normally.  ^If the commit hook
+** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
+** ^The rollback hook is invoked on a rollback that results from a commit
+** hook returning non-zero, just as it would be with any other rollback.
+**
+** ^For the purposes of this API, a transaction is said to have been
+** rolled back if an explicit "ROLLBACK" statement is executed, or
+** an error or constraint causes an implicit rollback to occur.
+** ^The rollback callback is not invoked if a transaction is
+** automatically rolled back because the database connection is closed.
+**
+** See also the [sqlite3_update_hook()] interface.
+*/
+SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
+SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
+
+/*
+** CAPI3REF: Autovacuum Compaction Amount Callback
+** METHOD: sqlite3
+**
+** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
+** function C that is invoked prior to each autovacuum of the database
+** file.  ^The callback is passed a copy of the generic data pointer (P),
+** the schema-name of the attached database that is being autovacuumed,
+** the size of the database file in pages, the number of free pages,
+** and the number of bytes per page, respectively.  The callback should
+** return the number of free pages that should be removed by the
+** autovacuum.  ^If the callback returns zero, then no autovacuum happens.
+** ^If the value returned is greater than or equal to the number of
+** free pages, then a complete autovacuum happens.
+**
+** <p>^If there are multiple ATTACH-ed database files that are being
+** modified as part of a transaction commit, then the autovacuum pages
+** callback is invoked separately for each file.
+**
+** <p><b>The callback is not reentrant.</b> The callback function should
+** not attempt to invoke any other SQLite interface.  If it does, bad
+** things may happen, including segmentation faults and corrupt database
+** files.  The callback function should be a simple function that
+** does some arithmetic on its input parameters and returns a result.
+**
+** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
+** destructor for the P parameter.  ^If X is not NULL, then X(P) is
+** invoked whenever the database connection closes or when the callback
+** is overwritten by another invocation of sqlite3_autovacuum_pages().
+**
+** <p>^There is only one autovacuum pages callback per database connection.
+** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
+** previous invocations for that database connection.  ^If the callback
+** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
+** then the autovacuum steps callback is canceled.  The return value
+** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
+** be some other error code if something goes wrong.  The current
+** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
+** return codes might be added in future releases.
+**
+** <p>If no autovacuum pages callback is specified (the usual case) or
+** a NULL pointer is provided for the callback,
+** then the default behavior is to vacuum all free pages.  So, in other
+** words, the default behavior is the same as if the callback function
+** were something like this:
+**
+** <blockquote><pre>
+**     unsigned int demonstration_autovac_pages_callback(
+**       void *pClientData,
+**       const char *zSchema,
+**       unsigned int nDbPage,
+**       unsigned int nFreePage,
+**       unsigned int nBytePerPage
+**     ){
+**       return nFreePage;
+**     }
+** </pre></blockquote>
+*/
+SQLITE_API int sqlite3_autovacuum_pages(
+  sqlite3 *db,
+  unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
+  void*,
+  void(*)(void*)
+);
+
+
+/*
+** CAPI3REF: Data Change Notification Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_update_hook() interface registers a callback function
+** with the [database connection] identified by the first argument
+** to be invoked whenever a row is updated, inserted or deleted in
+** a [rowid table].
+** ^Any callback set by a previous call to this function
+** for the same database connection is overridden.
+**
+** ^The second argument is a pointer to the function to invoke when a
+** row is updated, inserted or deleted in a rowid table.
+** ^The first argument to the callback is a copy of the third argument
+** to sqlite3_update_hook().
+** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
+** or [SQLITE_UPDATE], depending on the operation that caused the callback
+** to be invoked.
+** ^The third and fourth arguments to the callback contain pointers to the
+** database and table name containing the affected row.
+** ^The final callback parameter is the [rowid] of the row.
+** ^In the case of an update, this is the [rowid] after the update takes place.
+**
+** ^(The update hook is not invoked when internal system tables are
+** modified (i.e. sqlite_sequence).)^
+** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
+**
+** ^In the current implementation, the update hook
+** is not invoked when conflicting rows are deleted because of an
+** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
+** invoked when rows are deleted using the [truncate optimization].
+** The exceptions defined in this paragraph might change in a future
+** release of SQLite.
+**
+** Whether the update hook is invoked before or after the
+** corresponding change is currently unspecified and may differ
+** depending on the type of change. Do not rely on the order of the
+** hook call with regards to the final result of the operation which
+** triggers the hook.
+**
+** The update hook implementation must not do anything that will modify
+** the database connection that invoked the update hook.  Any actions
+** to modify the database connection must be deferred until after the
+** completion of the [sqlite3_step()] call that triggered the update hook.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** ^The sqlite3_update_hook(D,C,P) function
+** returns the P argument from the previous call
+** on the same [database connection] D, or NULL for
+** the first call on D.
+**
+** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
+** and [sqlite3_preupdate_hook()] interfaces.
+*/
+SQLITE_API void *sqlite3_update_hook(
+  sqlite3*,
+  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
+  void*
+);
+
+/*
+** CAPI3REF: Enable Or Disable Shared Pager Cache
+**
+** ^(This routine enables or disables the sharing of the database cache
+** and schema data structures between [database connection | connections]
+** to the same database. Sharing is enabled if the argument is true
+** and disabled if the argument is false.)^
+**
+** This interface is omitted if SQLite is compiled with
+** [-DSQLITE_OMIT_SHARED_CACHE].  The [-DSQLITE_OMIT_SHARED_CACHE]
+** compile-time option is recommended because the
+** [use of shared cache mode is discouraged].
+**
+** ^Cache sharing is enabled and disabled for an entire process.
+** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
+** In prior versions of SQLite,
+** sharing was enabled or disabled for each thread separately.
+**
+** ^(The cache sharing mode set by this interface effects all subsequent
+** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
+** Existing database connections continue to use the sharing mode
+** that was in effect at the time they were opened.)^
+**
+** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
+** successfully.  An [error code] is returned otherwise.)^
+**
+** ^Shared cache is disabled by default. It is recommended that it stay
+** that way.  In other words, do not use this routine.  This interface
+** continues to be provided for historical compatibility, but its use is
+** discouraged.  Any use of shared cache is discouraged.  If shared cache
+** must be used, it is recommended that shared cache only be enabled for
+** individual database connections using the [sqlite3_open_v2()] interface
+** with the [SQLITE_OPEN_SHAREDCACHE] flag.
+**
+** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
+** and will always return SQLITE_MISUSE. On those systems,
+** shared cache mode should be enabled per-database connection via
+** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
+**
+** This interface is threadsafe on processors where writing a
+** 32-bit integer is atomic.
+**
+** See Also:  [SQLite Shared-Cache Mode]
+*/
+SQLITE_API int sqlite3_enable_shared_cache(int);
+
+/*
+** CAPI3REF: Attempt To Free Heap Memory
+**
+** ^The sqlite3_release_memory() interface attempts to free N bytes
+** of heap memory by deallocating non-essential memory allocations
+** held by the database library.   Memory used to cache database
+** pages to improve performance is an example of non-essential memory.
+** ^sqlite3_release_memory() returns the number of bytes actually freed,
+** which might be more or less than the amount requested.
+** ^The sqlite3_release_memory() routine is a no-op returning zero
+** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
+**
+** See also: [sqlite3_db_release_memory()]
+*/
+SQLITE_API int sqlite3_release_memory(int);
+
+/*
+** CAPI3REF: Free Memory Used By A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
+** memory as possible from database connection D. Unlike the
+** [sqlite3_release_memory()] interface, this interface is in effect even
+** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
+** omitted.
+**
+** See also: [sqlite3_release_memory()]
+*/
+SQLITE_API int sqlite3_db_release_memory(sqlite3*);
+
+/*
+** CAPI3REF: Impose A Limit On Heap Size
+**
+** These interfaces impose limits on the amount of heap memory that will be
+** by all database connections within a single process.
+**
+** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
+** soft limit on the amount of heap memory that may be allocated by SQLite.
+** ^SQLite strives to keep heap memory utilization below the soft heap
+** limit by reducing the number of pages held in the page cache
+** as heap memory usages approaches the limit.
+** ^The soft heap limit is "soft" because even though SQLite strives to stay
+** below the limit, it will exceed the limit rather than generate
+** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
+** is advisory only.
+**
+** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
+** N bytes on the amount of memory that will be allocated.  ^The
+** sqlite3_hard_heap_limit64(N) interface is similar to
+** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
+** when the hard heap limit is reached.
+**
+** ^The return value from both sqlite3_soft_heap_limit64() and
+** sqlite3_hard_heap_limit64() is the size of
+** the heap limit prior to the call, or negative in the case of an
+** error.  ^If the argument N is negative
+** then no change is made to the heap limit.  Hence, the current
+** size of heap limits can be determined by invoking
+** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
+**
+** ^Setting the heap limits to zero disables the heap limiter mechanism.
+**
+** ^The soft heap limit may not be greater than the hard heap limit.
+** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
+** is invoked with a value of N that is greater than the hard heap limit,
+** the soft heap limit is set to the value of the hard heap limit.
+** ^The soft heap limit is automatically enabled whenever the hard heap
+** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
+** the soft heap limit is outside the range of 1..N, then the soft heap
+** limit is set to N.  ^Invoking sqlite3_soft_heap_limit64(0) when the
+** hard heap limit is enabled makes the soft heap limit equal to the
+** hard heap limit.
+**
+** The memory allocation limits can also be adjusted using
+** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
+**
+** ^(The heap limits are not enforced in the current implementation
+** if one or more of following conditions are true:
+**
+** <ul>
+** <li> The limit value is set to zero.
+** <li> Memory accounting is disabled using a combination of the
+**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
+**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
+** <li> An alternative page cache implementation is specified using
+**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
+** <li> The page cache allocates from its own memory pool supplied
+**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
+**      from the heap.
+** </ul>)^
+**
+** The circumstances under which SQLite will enforce the heap limits may
+** changes in future releases of SQLite.
+*/
+SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
+SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
+
+/*
+** CAPI3REF: Deprecated Soft Heap Limit Interface
+** DEPRECATED
+**
+** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
+** interface.  This routine is provided for historical compatibility
+** only.  All new applications should use the
+** [sqlite3_soft_heap_limit64()] interface rather than this one.
+*/
+SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
+
+
+/*
+** CAPI3REF: Extract Metadata About A Column Of A Table
+** METHOD: sqlite3
+**
+** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
+** information about column C of table T in database D
+** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
+** interface returns SQLITE_OK and fills in the non-NULL pointers in
+** the final five arguments with appropriate values if the specified
+** column exists.  ^The sqlite3_table_column_metadata() interface returns
+** SQLITE_ERROR if the specified column does not exist.
+** ^If the column-name parameter to sqlite3_table_column_metadata() is a
+** NULL pointer, then this routine simply checks for the existence of the
+** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
+** does not.  If the table name parameter T in a call to
+** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
+** undefined behavior.
+**
+** ^The column is identified by the second, third and fourth parameters to
+** this function. ^(The second parameter is either the name of the database
+** (i.e. "main", "temp", or an attached database) containing the specified
+** table or NULL.)^ ^If it is NULL, then all attached databases are searched
+** for the table using the same algorithm used by the database engine to
+** resolve unqualified table references.
+**
+** ^The third and fourth parameters to this function are the table and column
+** name of the desired column, respectively.
+**
+** ^Metadata is returned by writing to the memory locations passed as the 5th
+** and subsequent parameters to this function. ^Any of these arguments may be
+** NULL, in which case the corresponding element of metadata is omitted.
+**
+** ^(<blockquote>
+** <table border="1">
+** <tr><th> Parameter <th> Output<br>Type <th>  Description
+**
+** <tr><td> 5th <td> const char* <td> Data type
+** <tr><td> 6th <td> const char* <td> Name of default collation sequence
+** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
+** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
+** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
+** </table>
+** </blockquote>)^
+**
+** ^The memory pointed to by the character pointers returned for the
+** declaration type and collation sequence is valid until the next
+** call to any SQLite API function.
+**
+** ^If the specified table is actually a view, an [error code] is returned.
+**
+** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
+** is not a [WITHOUT ROWID] table and an
+** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
+** parameters are set for the explicitly declared column. ^(If there is no
+** [INTEGER PRIMARY KEY] column, then the outputs
+** for the [rowid] are set as follows:
+**
+** <pre>
+**     data type: "INTEGER"
+**     collation sequence: "BINARY"
+**     not null: 0
+**     primary key: 1
+**     auto increment: 0
+** </pre>)^
+**
+** ^This function causes all database schemas to be read from disk and
+** parsed, if that has not already been done, and returns an error if
+** any errors are encountered while loading the schema.
+*/
+SQLITE_API int sqlite3_table_column_metadata(
+  sqlite3 *db,                /* Connection handle */
+  const char *zDbName,        /* Database name or NULL */
+  const char *zTableName,     /* Table name */
+  const char *zColumnName,    /* Column name */
+  char const **pzDataType,    /* OUTPUT: Declared data type */
+  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
+  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
+  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
+  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
+);
+
+/*
+** CAPI3REF: Load An Extension
+** METHOD: sqlite3
+**
+** ^This interface loads an SQLite extension library from the named file.
+**
+** ^The sqlite3_load_extension() interface attempts to load an
+** [SQLite extension] library contained in the file zFile.  If
+** the file cannot be loaded directly, attempts are made to load
+** with various operating-system specific extensions added.
+** So for example, if "samplelib" cannot be loaded, then names like
+** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
+** be tried also.
+**
+** ^The entry point is zProc.
+** ^(zProc may be 0, in which case SQLite will try to come up with an
+** entry point name on its own.  It first tries "sqlite3_extension_init".
+** If that does not work, it constructs a name "sqlite3_X_init" where the
+** X is consists of the lower-case equivalent of all ASCII alphabetic
+** characters in the filename from the last "/" to the first following
+** "." and omitting any initial "lib".)^
+** ^The sqlite3_load_extension() interface returns
+** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
+** ^If an error occurs and pzErrMsg is not 0, then the
+** [sqlite3_load_extension()] interface shall attempt to
+** fill *pzErrMsg with error message text stored in memory
+** obtained from [sqlite3_malloc()]. The calling function
+** should free this memory by calling [sqlite3_free()].
+**
+** ^Extension loading must be enabled using
+** [sqlite3_enable_load_extension()] or
+** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
+** prior to calling this API,
+** otherwise an error will be returned.
+**
+** <b>Security warning:</b> It is recommended that the
+** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
+** interface.  The use of the [sqlite3_enable_load_extension()] interface
+** should be avoided.  This will keep the SQL function [load_extension()]
+** disabled and prevent SQL injections from giving attackers
+** access to extension loading capabilities.
+**
+** See also the [load_extension() SQL function].
+*/
+SQLITE_API int sqlite3_load_extension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+);
+
+/*
+** CAPI3REF: Enable Or Disable Extension Loading
+** METHOD: sqlite3
+**
+** ^So as not to open security holes in older applications that are
+** unprepared to deal with [extension loading], and as a means of disabling
+** [extension loading] while evaluating user-entered SQL, the following API
+** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
+**
+** ^Extension loading is off by default.
+** ^Call the sqlite3_enable_load_extension() routine with onoff==1
+** to turn extension loading on and call it with onoff==0 to turn
+** it back off again.
+**
+** ^This interface enables or disables both the C-API
+** [sqlite3_load_extension()] and the SQL function [load_extension()].
+** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
+** to enable or disable only the C-API.)^
+**
+** <b>Security warning:</b> It is recommended that extension loading
+** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
+** rather than this interface, so the [load_extension()] SQL function
+** remains disabled. This will prevent SQL injections from giving attackers
+** access to extension loading capabilities.
+*/
+SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
+
+/*
+** CAPI3REF: Automatically Load Statically Linked Extensions
+**
+** ^This interface causes the xEntryPoint() function to be invoked for
+** each new [database connection] that is created.  The idea here is that
+** xEntryPoint() is the entry point for a statically linked [SQLite extension]
+** that is to be automatically loaded into all new database connections.
+**
+** ^(Even though the function prototype shows that xEntryPoint() takes
+** no arguments and returns void, SQLite invokes xEntryPoint() with three
+** arguments and expects an integer result as if the signature of the
+** entry point where as follows:
+**
+** <blockquote><pre>
+**    int xEntryPoint(
+**      sqlite3 *db,
+**      const char **pzErrMsg,
+**      const struct sqlite3_api_routines *pThunk
+**    );
+** </pre></blockquote>)^
+**
+** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
+** point to an appropriate error message (obtained from [sqlite3_mprintf()])
+** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
+** is NULL before calling the xEntryPoint().  ^SQLite will invoke
+** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
+** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
+** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
+**
+** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
+** on the list of automatic extensions is a harmless no-op. ^No entry point
+** will be called more than once for each database connection that is opened.
+**
+** See also: [sqlite3_reset_auto_extension()]
+** and [sqlite3_cancel_auto_extension()]
+*/
+SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
+
+/*
+** CAPI3REF: Cancel Automatic Extension Loading
+**
+** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
+** initialization routine X that was registered using a prior call to
+** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
+** routine returns 1 if initialization routine X was successfully
+** unregistered and it returns 0 if X was not on the list of initialization
+** routines.
+*/
+SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
+
+/*
+** CAPI3REF: Reset Automatic Extension Loading
+**
+** ^This interface disables all automatic extensions previously
+** registered using [sqlite3_auto_extension()].
+*/
+SQLITE_API void sqlite3_reset_auto_extension(void);
+
+/*
+** Structures used by the virtual table interface
+*/
+typedef struct sqlite3_vtab sqlite3_vtab;
+typedef struct sqlite3_index_info sqlite3_index_info;
+typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
+typedef struct sqlite3_module sqlite3_module;
+
+/*
+** CAPI3REF: Virtual Table Object
+** KEYWORDS: sqlite3_module {virtual table module}
+**
+** This structure, sometimes called a "virtual table module",
+** defines the implementation of a [virtual table].
+** This structure consists mostly of methods for the module.
+**
+** ^A virtual table module is created by filling in a persistent
+** instance of this structure and passing a pointer to that instance
+** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
+** ^The registration remains valid until it is replaced by a different
+** module or until the [database connection] closes.  The content
+** of this structure must not change while it is registered with
+** any database connection.
+*/
+struct sqlite3_module {
+  int iVersion;
+  int (*xCreate)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xConnect)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
+  int (*xDisconnect)(sqlite3_vtab *pVTab);
+  int (*xDestroy)(sqlite3_vtab *pVTab);
+  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
+  int (*xClose)(sqlite3_vtab_cursor*);
+  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
+                int argc, sqlite3_value **argv);
+  int (*xNext)(sqlite3_vtab_cursor*);
+  int (*xEof)(sqlite3_vtab_cursor*);
+  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
+  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
+  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
+  int (*xBegin)(sqlite3_vtab *pVTab);
+  int (*xSync)(sqlite3_vtab *pVTab);
+  int (*xCommit)(sqlite3_vtab *pVTab);
+  int (*xRollback)(sqlite3_vtab *pVTab);
+  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
+                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
+                       void **ppArg);
+  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
+  /* The methods above are in version 1 of the sqlite_module object. Those
+  ** below are for version 2 and greater. */
+  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
+  int (*xRelease)(sqlite3_vtab *pVTab, int);
+  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
+  /* The methods above are in versions 1 and 2 of the sqlite_module object.
+  ** Those below are for version 3 and greater. */
+  int (*xShadowName)(const char*);
+  /* The methods above are in versions 1 through 3 of the sqlite_module object.
+  ** Those below are for version 4 and greater. */
+  int (*xIntegrity)(sqlite3_vtab *pVTab, const char *zSchema,
+                    const char *zTabName, int mFlags, char **pzErr);
+};
+
+/*
+** CAPI3REF: Virtual Table Indexing Information
+** KEYWORDS: sqlite3_index_info
+**
+** The sqlite3_index_info structure and its substructures is used as part
+** of the [virtual table] interface to
+** pass information into and receive the reply from the [xBestIndex]
+** method of a [virtual table module].  The fields under **Inputs** are the
+** inputs to xBestIndex and are read-only.  xBestIndex inserts its
+** results into the **Outputs** fields.
+**
+** ^(The aConstraint[] array records WHERE clause constraints of the form:
+**
+** <blockquote>column OP expr</blockquote>
+**
+** where OP is =, <, <=, >, or >=.)^  ^(The particular operator is
+** stored in aConstraint[].op using one of the
+** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
+** ^(The index of the column is stored in
+** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
+** expr on the right-hand side can be evaluated (and thus the constraint
+** is usable) and false if it cannot.)^
+**
+** ^The optimizer automatically inverts terms of the form "expr OP column"
+** and makes other simplifications to the WHERE clause in an attempt to
+** get as many WHERE clause terms into the form shown above as possible.
+** ^The aConstraint[] array only reports WHERE clause terms that are
+** relevant to the particular virtual table being queried.
+**
+** ^Information about the ORDER BY clause is stored in aOrderBy[].
+** ^Each term of aOrderBy records a column of the ORDER BY clause.
+**
+** The colUsed field indicates which columns of the virtual table may be
+** required by the current scan. Virtual table columns are numbered from
+** zero in the order in which they appear within the CREATE TABLE statement
+** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
+** the corresponding bit is set within the colUsed mask if the column may be
+** required by SQLite. If the table has at least 64 columns and any column
+** to the right of the first 63 is required, then bit 63 of colUsed is also
+** set. In other words, column iCol may be required if the expression
+** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
+** non-zero.
+**
+** The [xBestIndex] method must fill aConstraintUsage[] with information
+** about what parameters to pass to xFilter.  ^If argvIndex>0 then
+** the right-hand side of the corresponding aConstraint[] is evaluated
+** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
+** is true, then the constraint is assumed to be fully handled by the
+** virtual table and might not be checked again by the byte code.)^ ^(The
+** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
+** is left in its default setting of false, the constraint will always be
+** checked separately in byte code.  If the omit flag is change to true, then
+** the constraint may or may not be checked in byte code.  In other words,
+** when the omit flag is true there is no guarantee that the constraint will
+** not be checked again using byte code.)^
+**
+** ^The idxNum and idxStr values are recorded and passed into the
+** [xFilter] method.
+** ^[sqlite3_free()] is used to free idxStr if and only if
+** needToFreeIdxStr is true.
+**
+** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
+** the correct order to satisfy the ORDER BY clause so that no separate
+** sorting step is required.
+**
+** ^The estimatedCost value is an estimate of the cost of a particular
+** strategy. A cost of N indicates that the cost of the strategy is similar
+** to a linear scan of an SQLite table with N rows. A cost of log(N)
+** indicates that the expense of the operation is similar to that of a
+** binary search on a unique indexed field of an SQLite table with N rows.
+**
+** ^The estimatedRows value is an estimate of the number of rows that
+** will be returned by the strategy.
+**
+** The xBestIndex method may optionally populate the idxFlags field with a
+** mask of SQLITE_INDEX_SCAN_* flags. One such flag is
+** [SQLITE_INDEX_SCAN_HEX], which if set causes the [EXPLAIN QUERY PLAN]
+** output to show the idxNum has hex instead of as decimal.  Another flag is
+** SQLITE_INDEX_SCAN_UNIQUE, which if set indicates that the query plan will
+** return at most one row.
+**
+** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
+** SQLite also assumes that if a call to the xUpdate() method is made as
+** part of the same statement to delete or update a virtual table row and the
+** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
+** any database changes. In other words, if the xUpdate() returns
+** SQLITE_CONSTRAINT, the database contents must be exactly as they were
+** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
+** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
+** the xUpdate method are automatically rolled back by SQLite.
+**
+** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
+** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
+** If a virtual table extension is
+** used with an SQLite version earlier than 3.8.2, the results of attempting
+** to read or write the estimatedRows field are undefined (but are likely
+** to include crashing the application). The estimatedRows field should
+** therefore only be used if [sqlite3_libversion_number()] returns a
+** value greater than or equal to 3008002. Similarly, the idxFlags field
+** was added for [version 3.9.0] ([dateof:3.9.0]).
+** It may therefore only be used if
+** sqlite3_libversion_number() returns a value greater than or equal to
+** 3009000.
+*/
+struct sqlite3_index_info {
+  /* Inputs */
+  int nConstraint;           /* Number of entries in aConstraint */
+  struct sqlite3_index_constraint {
+     int iColumn;              /* Column constrained.  -1 for ROWID */
+     unsigned char op;         /* Constraint operator */
+     unsigned char usable;     /* True if this constraint is usable */
+     int iTermOffset;          /* Used internally - xBestIndex should ignore */
+  } *aConstraint;            /* Table of WHERE clause constraints */
+  int nOrderBy;              /* Number of terms in the ORDER BY clause */
+  struct sqlite3_index_orderby {
+     int iColumn;              /* Column number */
+     unsigned char desc;       /* True for DESC.  False for ASC. */
+  } *aOrderBy;               /* The ORDER BY clause */
+  /* Outputs */
+  struct sqlite3_index_constraint_usage {
+    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
+    unsigned char omit;      /* Do not code a test for this constraint */
+  } *aConstraintUsage;
+  int idxNum;                /* Number used to identify the index */
+  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
+  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
+  int orderByConsumed;       /* True if output is already ordered */
+  double estimatedCost;           /* Estimated cost of using this index */
+  /* Fields below are only available in SQLite 3.8.2 and later */
+  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
+  /* Fields below are only available in SQLite 3.9.0 and later */
+  int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
+  /* Fields below are only available in SQLite 3.10.0 and later */
+  sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
+};
+
+/*
+** CAPI3REF: Virtual Table Scan Flags
+**
+** Virtual table implementations are allowed to set the
+** [sqlite3_index_info].idxFlags field to some combination of
+** these bits.
+*/
+#define SQLITE_INDEX_SCAN_UNIQUE 0x00000001 /* Scan visits at most 1 row */
+#define SQLITE_INDEX_SCAN_HEX    0x00000002 /* Display idxNum as hex */
+                                            /* in EXPLAIN QUERY PLAN */
+
+/*
+** CAPI3REF: Virtual Table Constraint Operator Codes
+**
+** These macros define the allowed values for the
+** [sqlite3_index_info].aConstraint[].op field.  Each value represents
+** an operator that is part of a constraint term in the WHERE clause of
+** a query that uses a [virtual table].
+**
+** ^The left-hand operand of the operator is given by the corresponding
+** aConstraint[].iColumn field.  ^An iColumn of -1 indicates the left-hand
+** operand is the rowid.
+** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
+** operators have no left-hand operand, and so for those operators the
+** corresponding aConstraint[].iColumn is meaningless and should not be
+** used.
+**
+** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
+** value 255 are reserved to represent functions that are overloaded
+** by the [xFindFunction|xFindFunction method] of the virtual table
+** implementation.
+**
+** The right-hand operands for each constraint might be accessible using
+** the [sqlite3_vtab_rhs_value()] interface.  Usually the right-hand
+** operand is only available if it appears as a single constant literal
+** in the input SQL.  If the right-hand operand is another column or an
+** expression (even a constant expression) or a parameter, then the
+** sqlite3_vtab_rhs_value() probably will not be able to extract it.
+** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
+** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
+** and hence calls to sqlite3_vtab_rhs_value() for those operators will
+** always return SQLITE_NOTFOUND.
+**
+** The collating sequence to be used for comparison can be found using
+** the [sqlite3_vtab_collation()] interface.  For most real-world virtual
+** tables, the collating sequence of constraints does not matter (for example
+** because the constraints are numeric) and so the sqlite3_vtab_collation()
+** interface is not commonly needed.
+*/
+#define SQLITE_INDEX_CONSTRAINT_EQ          2
+#define SQLITE_INDEX_CONSTRAINT_GT          4
+#define SQLITE_INDEX_CONSTRAINT_LE          8
+#define SQLITE_INDEX_CONSTRAINT_LT         16
+#define SQLITE_INDEX_CONSTRAINT_GE         32
+#define SQLITE_INDEX_CONSTRAINT_MATCH      64
+#define SQLITE_INDEX_CONSTRAINT_LIKE       65
+#define SQLITE_INDEX_CONSTRAINT_GLOB       66
+#define SQLITE_INDEX_CONSTRAINT_REGEXP     67
+#define SQLITE_INDEX_CONSTRAINT_NE         68
+#define SQLITE_INDEX_CONSTRAINT_ISNOT      69
+#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL  70
+#define SQLITE_INDEX_CONSTRAINT_ISNULL     71
+#define SQLITE_INDEX_CONSTRAINT_IS         72
+#define SQLITE_INDEX_CONSTRAINT_LIMIT      73
+#define SQLITE_INDEX_CONSTRAINT_OFFSET     74
+#define SQLITE_INDEX_CONSTRAINT_FUNCTION  150
+
+/*
+** CAPI3REF: Register A Virtual Table Implementation
+** METHOD: sqlite3
+**
+** ^These routines are used to register a new [virtual table module] name.
+** ^Module names must be registered before
+** creating a new [virtual table] using the module and before using a
+** preexisting [virtual table] for the module.
+**
+** ^The module name is registered on the [database connection] specified
+** by the first parameter.  ^The name of the module is given by the
+** second parameter.  ^The third parameter is a pointer to
+** the implementation of the [virtual table module].   ^The fourth
+** parameter is an arbitrary client data pointer that is passed through
+** into the [xCreate] and [xConnect] methods of the virtual table module
+** when a new virtual table is be being created or reinitialized.
+**
+** ^The sqlite3_create_module_v2() interface has a fifth parameter which
+** is a pointer to a destructor for the pClientData.  ^SQLite will
+** invoke the destructor function (if it is not NULL) when SQLite
+** no longer needs the pClientData pointer.  ^The destructor will also
+** be invoked if the call to sqlite3_create_module_v2() fails.
+** ^The sqlite3_create_module()
+** interface is equivalent to sqlite3_create_module_v2() with a NULL
+** destructor.
+**
+** ^If the third parameter (the pointer to the sqlite3_module object) is
+** NULL then no new module is created and any existing modules with the
+** same name are dropped.
+**
+** See also: [sqlite3_drop_modules()]
+*/
+SQLITE_API int sqlite3_create_module(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData          /* Client data for xCreate/xConnect */
+);
+SQLITE_API int sqlite3_create_module_v2(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData,         /* Client data for xCreate/xConnect */
+  void(*xDestroy)(void*)     /* Module destructor function */
+);
+
+/*
+** CAPI3REF: Remove Unnecessary Virtual Table Implementations
+** METHOD: sqlite3
+**
+** ^The sqlite3_drop_modules(D,L) interface removes all virtual
+** table modules from database connection D except those named on list L.
+** The L parameter must be either NULL or a pointer to an array of pointers
+** to strings where the array is terminated by a single NULL pointer.
+** ^If the L parameter is NULL, then all virtual table modules are removed.
+**
+** See also: [sqlite3_create_module()]
+*/
+SQLITE_API int sqlite3_drop_modules(
+  sqlite3 *db,                /* Remove modules from this connection */
+  const char **azKeep         /* Except, do not remove the ones named here */
+);
+
+/*
+** CAPI3REF: Virtual Table Instance Object
+** KEYWORDS: sqlite3_vtab
+**
+** Every [virtual table module] implementation uses a subclass
+** of this object to describe a particular instance
+** of the [virtual table].  Each subclass will
+** be tailored to the specific needs of the module implementation.
+** The purpose of this superclass is to define certain fields that are
+** common to all module implementations.
+**
+** ^Virtual tables methods can set an error message by assigning a
+** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
+** take care that any prior string is freed by a call to [sqlite3_free()]
+** prior to assigning a new string to zErrMsg.  ^After the error message
+** is delivered up to the client application, the string will be automatically
+** freed by sqlite3_free() and the zErrMsg field will be zeroed.
+*/
+struct sqlite3_vtab {
+  const sqlite3_module *pModule;  /* The module for this virtual table */
+  int nRef;                       /* Number of open cursors */
+  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Virtual Table Cursor Object
+** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
+**
+** Every [virtual table module] implementation uses a subclass of the
+** following structure to describe cursors that point into the
+** [virtual table] and are used
+** to loop through the virtual table.  Cursors are created using the
+** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
+** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
+** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
+** of the module.  Each module implementation will define
+** the content of a cursor structure to suit its own needs.
+**
+** This superclass exists in order to define fields of the cursor that
+** are common to all implementations.
+*/
+struct sqlite3_vtab_cursor {
+  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Declare The Schema Of A Virtual Table
+**
+** ^The [xCreate] and [xConnect] methods of a
+** [virtual table module] call this interface
+** to declare the format (the names and datatypes of the columns) of
+** the virtual tables they implement.
+*/
+SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
+
+/*
+** CAPI3REF: Overload A Function For A Virtual Table
+** METHOD: sqlite3
+**
+** ^(Virtual tables can provide alternative implementations of functions
+** using the [xFindFunction] method of the [virtual table module].
+** But global versions of those functions
+** must exist in order to be overloaded.)^
+**
+** ^(This API makes sure a global version of a function with a particular
+** name and number of parameters exists.  If no such function exists
+** before this API is called, a new function is created.)^  ^The implementation
+** of the new function always causes an exception to be thrown.  So
+** the new function is not good for anything by itself.  Its only
+** purpose is to be a placeholder function that can be overloaded
+** by a [virtual table].
+*/
+SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
+
+/*
+** CAPI3REF: A Handle To An Open BLOB
+** KEYWORDS: {BLOB handle} {BLOB handles}
+**
+** An instance of this object represents an open BLOB on which
+** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
+** ^Objects of this type are created by [sqlite3_blob_open()]
+** and destroyed by [sqlite3_blob_close()].
+** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
+** can be used to read or write small subsections of the BLOB.
+** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
+*/
+typedef struct sqlite3_blob sqlite3_blob;
+
+/*
+** CAPI3REF: Open A BLOB For Incremental I/O
+** METHOD: sqlite3
+** CONSTRUCTOR: sqlite3_blob
+**
+** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
+** in row iRow, column zColumn, table zTable in database zDb;
+** in other words, the same BLOB that would be selected by:
+**
+** <pre>
+**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
+** </pre>)^
+**
+** ^(Parameter zDb is not the filename that contains the database, but
+** rather the symbolic name of the database. For attached databases, this is
+** the name that appears after the AS keyword in the [ATTACH] statement.
+** For the main database file, the database name is "main". For TEMP
+** tables, the database name is "temp".)^
+**
+** ^If the flags parameter is non-zero, then the BLOB is opened for read
+** and write access. ^If the flags parameter is zero, the BLOB is opened for
+** read-only access.
+**
+** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
+** in *ppBlob. Otherwise an [error code] is returned and, unless the error
+** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
+** the API is not misused, it is always safe to call [sqlite3_blob_close()]
+** on *ppBlob after this function it returns.
+**
+** This function fails with SQLITE_ERROR if any of the following are true:
+** <ul>
+**   <li> ^(Database zDb does not exist)^,
+**   <li> ^(Table zTable does not exist within database zDb)^,
+**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
+**   <li> ^(Column zColumn does not exist)^,
+**   <li> ^(Row iRow is not present in the table)^,
+**   <li> ^(The specified column of row iRow contains a value that is not
+**         a TEXT or BLOB value)^,
+**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
+**         constraint and the blob is being opened for read/write access)^,
+**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
+**         column zColumn is part of a [child key] definition and the blob is
+**         being opened for read/write access)^.
+** </ul>
+**
+** ^Unless it returns SQLITE_MISUSE, this function sets the
+** [database connection] error code and message accessible via
+** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
+**
+** A BLOB referenced by sqlite3_blob_open() may be read using the
+** [sqlite3_blob_read()] interface and modified by using
+** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
+** different row of the same table using the [sqlite3_blob_reopen()]
+** interface.  However, the column, table, or database of a [BLOB handle]
+** cannot be changed after the [BLOB handle] is opened.
+**
+** ^(If the row that a BLOB handle points to is modified by an
+** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
+** then the BLOB handle is marked as "expired".
+** This is true if any column of the row is changed, even a column
+** other than the one the BLOB handle is open on.)^
+** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
+** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
+** ^(Changes written into a BLOB prior to the BLOB expiring are not
+** rolled back by the expiration of the BLOB.  Such changes will eventually
+** commit if the transaction continues to completion.)^
+**
+** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
+** the opened blob.  ^The size of a blob may not be changed by this
+** interface.  Use the [UPDATE] SQL command to change the size of a
+** blob.
+**
+** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
+** and the built-in [zeroblob] SQL function may be used to create a
+** zero-filled blob to read or write using the incremental-blob interface.
+**
+** To avoid a resource leak, every open [BLOB handle] should eventually
+** be released by a call to [sqlite3_blob_close()].
+**
+** See also: [sqlite3_blob_close()],
+** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
+** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
+*/
+SQLITE_API int sqlite3_blob_open(
+  sqlite3*,
+  const char *zDb,
+  const char *zTable,
+  const char *zColumn,
+  sqlite3_int64 iRow,
+  int flags,
+  sqlite3_blob **ppBlob
+);
+
+/*
+** CAPI3REF: Move a BLOB Handle to a New Row
+** METHOD: sqlite3_blob
+**
+** ^This function is used to move an existing [BLOB handle] so that it points
+** to a different row of the same database table. ^The new row is identified
+** by the rowid value passed as the second argument. Only the row can be
+** changed. ^The database, table and column on which the blob handle is open
+** remain the same. Moving an existing [BLOB handle] to a new row is
+** faster than closing the existing handle and opening a new one.
+**
+** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
+** it must exist and there must be either a blob or text value stored in
+** the nominated column.)^ ^If the new row is not present in the table, or if
+** it does not contain a blob or text value, or if another error occurs, an
+** SQLite error code is returned and the blob handle is considered aborted.
+** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
+** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
+** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
+** always returns zero.
+**
+** ^This function sets the database handle error code and message.
+*/
+SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
+
+/*
+** CAPI3REF: Close A BLOB Handle
+** DESTRUCTOR: sqlite3_blob
+**
+** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
+** unconditionally.  Even if this routine returns an error code, the
+** handle is still closed.)^
+**
+** ^If the blob handle being closed was opened for read-write access, and if
+** the database is in auto-commit mode and there are no other open read-write
+** blob handles or active write statements, the current transaction is
+** committed. ^If an error occurs while committing the transaction, an error
+** code is returned and the transaction rolled back.
+**
+** Calling this function with an argument that is not a NULL pointer or an
+** open blob handle results in undefined behavior. ^Calling this routine
+** with a null pointer (such as would be returned by a failed call to
+** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
+** is passed a valid open blob handle, the values returned by the
+** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
+*/
+SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
+
+/*
+** CAPI3REF: Return The Size Of An Open BLOB
+** METHOD: sqlite3_blob
+**
+** ^Returns the size in bytes of the BLOB accessible via the
+** successfully opened [BLOB handle] in its only argument.  ^The
+** incremental blob I/O routines can only read or overwriting existing
+** blob content; they cannot change the size of a blob.
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+*/
+SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
+
+/*
+** CAPI3REF: Read Data From A BLOB Incrementally
+** METHOD: sqlite3_blob
+**
+** ^(This function is used to read data from an open [BLOB handle] into a
+** caller-supplied buffer. N bytes of data are copied into buffer Z
+** from the open BLOB, starting at offset iOffset.)^
+**
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
+** less than zero, [SQLITE_ERROR] is returned and no data is read.
+** ^The size of the blob (and hence the maximum value of N+iOffset)
+** can be determined using the [sqlite3_blob_bytes()] interface.
+**
+** ^An attempt to read from an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].
+**
+** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
+** Otherwise, an [error code] or an [extended error code] is returned.)^
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+**
+** See also: [sqlite3_blob_write()].
+*/
+SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
+
+/*
+** CAPI3REF: Write Data Into A BLOB Incrementally
+** METHOD: sqlite3_blob
+**
+** ^(This function is used to write data into an open [BLOB handle] from a
+** caller-supplied buffer. N bytes of data are copied from the buffer Z
+** into the open BLOB, starting at offset iOffset.)^
+**
+** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
+** Otherwise, an  [error code] or an [extended error code] is returned.)^
+** ^Unless SQLITE_MISUSE is returned, this function sets the
+** [database connection] error code and message accessible via
+** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
+**
+** ^If the [BLOB handle] passed as the first argument was not opened for
+** writing (the flags parameter to [sqlite3_blob_open()] was zero),
+** this function returns [SQLITE_READONLY].
+**
+** This function may only modify the contents of the BLOB; it is
+** not possible to increase the size of a BLOB using this API.
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is written. The size of the
+** BLOB (and hence the maximum value of N+iOffset) can be determined
+** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
+** than zero [SQLITE_ERROR] is returned and no data is written.
+**
+** ^An attempt to write to an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
+** before the [BLOB handle] expired are not rolled back by the
+** expiration of the handle, though of course those changes might
+** have been overwritten by the statement that expired the BLOB handle
+** or by other independent statements.
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+**
+** See also: [sqlite3_blob_read()].
+*/
+SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
+
+/*
+** CAPI3REF: Virtual File System Objects
+**
+** A virtual filesystem (VFS) is an [sqlite3_vfs] object
+** that SQLite uses to interact
+** with the underlying operating system.  Most SQLite builds come with a
+** single default VFS that is appropriate for the host computer.
+** New VFSes can be registered and existing VFSes can be unregistered.
+** The following interfaces are provided.
+**
+** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
+** ^Names are case sensitive.
+** ^Names are zero-terminated UTF-8 strings.
+** ^If there is no match, a NULL pointer is returned.
+** ^If zVfsName is NULL then the default VFS is returned.
+**
+** ^New VFSes are registered with sqlite3_vfs_register().
+** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
+** ^The same VFS can be registered multiple times without injury.
+** ^To make an existing VFS into the default VFS, register it again
+** with the makeDflt flag set.  If two different VFSes with the
+** same name are registered, the behavior is undefined.  If a
+** VFS is registered with a name that is NULL or an empty string,
+** then the behavior is undefined.
+**
+** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
+** ^(If the default VFS is unregistered, another VFS is chosen as
+** the default.  The choice for the new VFS is arbitrary.)^
+*/
+SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
+SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
+SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
+
+/*
+** CAPI3REF: Mutexes
+**
+** The SQLite core uses these routines for thread
+** synchronization. Though they are intended for internal
+** use by SQLite, code that links against SQLite is
+** permitted to use any of these routines.
+**
+** The SQLite source code contains multiple implementations
+** of these mutex routines.  An appropriate implementation
+** is selected automatically at compile-time.  The following
+** implementations are available in the SQLite core:
+**
+** <ul>
+** <li>   SQLITE_MUTEX_PTHREADS
+** <li>   SQLITE_MUTEX_W32
+** <li>   SQLITE_MUTEX_NOOP
+** </ul>
+**
+** The SQLITE_MUTEX_NOOP implementation is a set of routines
+** that does no real locking and is appropriate for use in
+** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
+** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
+** and Windows.
+**
+** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
+** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
+** implementation is included with the library. In this case the
+** application must supply a custom mutex implementation using the
+** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
+** before calling sqlite3_initialize() or any other public sqlite3_
+** function that calls sqlite3_initialize().
+**
+** ^The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
+** routine returns NULL if it is unable to allocate the requested
+** mutex.  The argument to sqlite3_mutex_alloc() must one of these
+** integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MAIN
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_OPEN
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
+** <li>  SQLITE_MUTEX_STATIC_APP1
+** <li>  SQLITE_MUTEX_STATIC_APP2
+** <li>  SQLITE_MUTEX_STATIC_APP3
+** <li>  SQLITE_MUTEX_STATIC_VFS1
+** <li>  SQLITE_MUTEX_STATIC_VFS2
+** <li>  SQLITE_MUTEX_STATIC_VFS3
+** </ul>
+**
+** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
+** cause sqlite3_mutex_alloc() to create
+** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
+** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
+** a pointer to a static preexisting mutex.  ^Nine static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  ^For the static
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+**
+** ^The sqlite3_mutex_free() routine deallocates a previously
+** allocated dynamic mutex.  Attempting to deallocate a static
+** mutex results in undefined behavior.
+**
+** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  ^If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
+** upon successful entry.  ^(Mutexes created using
+** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
+** In such cases, the
+** mutex must be exited an equal number of times before another thread
+** can enter.)^  If the same thread tries to enter any mutex other
+** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
+**
+** ^(Some systems (for example, Windows 95) do not support the operation
+** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
+** will always return SQLITE_BUSY. In most cases the SQLite core only uses
+** sqlite3_mutex_try() as an optimization, so this is acceptable
+** behavior. The exceptions are unix builds that set the
+** SQLITE_ENABLE_SETLK_TIMEOUT build option. In that case a working
+** sqlite3_mutex_try() is required.)^
+**
+** ^The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.   The behavior
+** is undefined if the mutex is not currently entered by the
+** calling thread or is not currently allocated.
+**
+** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(),
+** sqlite3_mutex_leave(), or sqlite3_mutex_free() is a NULL pointer,
+** then any of the four routines behaves as a no-op.
+**
+** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
+
+/*
+** CAPI3REF: Mutex Methods Object
+**
+** An instance of this structure defines the low-level routines
+** used to allocate and use mutexes.
+**
+** Usually, the default mutex implementations provided by SQLite are
+** sufficient, however the application has the option of substituting a custom
+** implementation for specialized deployments or systems for which SQLite
+** does not provide a suitable implementation. In this case, the application
+** creates and populates an instance of this structure to pass
+** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
+** Additionally, an instance of this structure can be used as an
+** output variable when querying the system for the current mutex
+** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
+**
+** ^The xMutexInit method defined by this structure is invoked as
+** part of system initialization by the sqlite3_initialize() function.
+** ^The xMutexInit routine is called by SQLite exactly once for each
+** effective call to [sqlite3_initialize()].
+**
+** ^The xMutexEnd method defined by this structure is invoked as
+** part of system shutdown by the sqlite3_shutdown() function. The
+** implementation of this method is expected to release all outstanding
+** resources obtained by the mutex methods implementation, especially
+** those obtained by the xMutexInit method.  ^The xMutexEnd()
+** interface is invoked exactly once for each call to [sqlite3_shutdown()].
+**
+** ^(The remaining seven methods defined by this structure (xMutexAlloc,
+** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
+** xMutexNotheld) implement the following interfaces (respectively):
+**
+** <ul>
+**   <li>  [sqlite3_mutex_alloc()] </li>
+**   <li>  [sqlite3_mutex_free()] </li>
+**   <li>  [sqlite3_mutex_enter()] </li>
+**   <li>  [sqlite3_mutex_try()] </li>
+**   <li>  [sqlite3_mutex_leave()] </li>
+**   <li>  [sqlite3_mutex_held()] </li>
+**   <li>  [sqlite3_mutex_notheld()] </li>
+** </ul>)^
+**
+** The only difference is that the public sqlite3_XXX functions enumerated
+** above silently ignore any invocations that pass a NULL pointer instead
+** of a valid mutex handle. The implementations of the methods defined
+** by this structure are not required to handle this case. The results
+** of passing a NULL pointer instead of a valid mutex handle are undefined
+** (i.e. it is acceptable to provide an implementation that segfaults if
+** it is passed a NULL pointer).
+**
+** The xMutexInit() method must be threadsafe.  It must be harmless to
+** invoke xMutexInit() multiple times within the same process and without
+** intervening calls to xMutexEnd().  Second and subsequent calls to
+** xMutexInit() must be no-ops.
+**
+** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
+** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
+** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
+** memory allocation for a fast or recursive mutex.
+**
+** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
+** called, but only if the prior call to xMutexInit returned SQLITE_OK.
+** If xMutexInit fails in any way, it is expected to clean up after itself
+** prior to returning.
+*/
+typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
+struct sqlite3_mutex_methods {
+  int (*xMutexInit)(void);
+  int (*xMutexEnd)(void);
+  sqlite3_mutex *(*xMutexAlloc)(int);
+  void (*xMutexFree)(sqlite3_mutex *);
+  void (*xMutexEnter)(sqlite3_mutex *);
+  int (*xMutexTry)(sqlite3_mutex *);
+  void (*xMutexLeave)(sqlite3_mutex *);
+  int (*xMutexHeld)(sqlite3_mutex *);
+  int (*xMutexNotheld)(sqlite3_mutex *);
+};
+
+/*
+** CAPI3REF: Mutex Verification Routines
+**
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
+** are intended for use inside assert() statements.  The SQLite core
+** never uses these routines except inside an assert() and applications
+** are advised to follow the lead of the core.  The SQLite core only
+** provides implementations for these routines when it is compiled
+** with the SQLITE_DEBUG flag.  External mutex implementations
+** are only required to provide these routines if SQLITE_DEBUG is
+** defined and if NDEBUG is not defined.
+**
+** These routines should return true if the mutex in their argument
+** is held or not held, respectively, by the calling thread.
+**
+** The implementation is not required to provide versions of these
+** routines that actually work. If the implementation does not provide working
+** versions of these routines, it should at least provide stubs that always
+** return true so that one does not get spurious assertion failures.
+**
+** If the argument to sqlite3_mutex_held() is a NULL pointer then
+** the routine should return 1.   This seems counter-intuitive since
+** clearly the mutex cannot be held if it does not exist.  But
+** the reason the mutex does not exist is because the build is not
+** using mutexes.  And we do not want the assert() containing the
+** call to sqlite3_mutex_held() to fail, so a non-zero return is
+** the appropriate thing to do.  The sqlite3_mutex_notheld()
+** interface should also return 1 when given a NULL pointer.
+*/
+#ifndef NDEBUG
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
+#endif
+
+/*
+** CAPI3REF: Mutex Types
+**
+** The [sqlite3_mutex_alloc()] interface takes a single argument
+** which is one of these integer constants.
+**
+** The set of static mutexes may change from one SQLite release to the
+** next.  Applications that override the built-in mutex logic must be
+** prepared to accommodate additional static mutexes.
+*/
+#define SQLITE_MUTEX_FAST             0
+#define SQLITE_MUTEX_RECURSIVE        1
+#define SQLITE_MUTEX_STATIC_MAIN      2
+#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
+#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
+#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
+#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
+#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
+#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
+#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
+#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
+#define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
+#define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
+#define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
+
+/* Legacy compatibility: */
+#define SQLITE_MUTEX_STATIC_MASTER    2
+
+
+/*
+** CAPI3REF: Retrieve the mutex for a database connection
+** METHOD: sqlite3
+**
+** ^This interface returns a pointer the [sqlite3_mutex] object that
+** serializes access to the [database connection] given in the argument
+** when the [threading mode] is Serialized.
+** ^If the [threading mode] is Single-thread or Multi-thread then this
+** routine returns a NULL pointer.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
+
+/*
+** CAPI3REF: Low-Level Control Of Database Files
+** METHOD: sqlite3
+** KEYWORDS: {file control}
+**
+** ^The [sqlite3_file_control()] interface makes a direct call to the
+** xFileControl method for the [sqlite3_io_methods] object associated
+** with a particular database identified by the second argument. ^The
+** name of the database is "main" for the main database or "temp" for the
+** TEMP database, or the name that appears after the AS keyword for
+** databases that are added using the [ATTACH] SQL command.
+** ^A NULL pointer can be used in place of "main" to refer to the
+** main database file.
+** ^The third and fourth parameters to this routine
+** are passed directly through to the second and third parameters of
+** the xFileControl method.  ^The return value of the xFileControl
+** method becomes the return value of this routine.
+**
+** A few opcodes for [sqlite3_file_control()] are handled directly
+** by the SQLite core and never invoke the
+** sqlite3_io_methods.xFileControl method.
+** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
+** a pointer to the underlying [sqlite3_file] object to be written into
+** the space pointed to by the 4th parameter.  The
+** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
+** the [sqlite3_file] object associated with the journal file instead of
+** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
+** a pointer to the underlying [sqlite3_vfs] object for the file.
+** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
+** from the pager.
+**
+** ^If the second parameter (zDbName) does not match the name of any
+** open database file, then SQLITE_ERROR is returned.  ^This error
+** code is not remembered and will not be recalled by [sqlite3_errcode()]
+** or [sqlite3_errmsg()].  The underlying xFileControl method might
+** also return SQLITE_ERROR.  There is no way to distinguish between
+** an incorrect zDbName and an SQLITE_ERROR return from the underlying
+** xFileControl method.
+**
+** See also: [file control opcodes]
+*/
+SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
+
+/*
+** CAPI3REF: Testing Interface
+**
+** ^The sqlite3_test_control() interface is used to read out internal
+** state of SQLite and to inject faults into SQLite for testing
+** purposes.  ^The first parameter is an operation code that determines
+** the number, meaning, and operation of all subsequent parameters.
+**
+** This interface is not for use by applications.  It exists solely
+** for verifying the correct operation of the SQLite library.  Depending
+** on how the SQLite library is compiled, this interface might not exist.
+**
+** The details of the operation codes, their meanings, the parameters
+** they take, and what they do are all subject to change without notice.
+** Unlike most of the SQLite API, this function is not guaranteed to
+** operate consistently from one release to the next.
+*/
+SQLITE_API int sqlite3_test_control(int op, ...);
+
+/*
+** CAPI3REF: Testing Interface Operation Codes
+**
+** These constants are the valid operation code parameters used
+** as the first argument to [sqlite3_test_control()].
+**
+** These parameters and their meanings are subject to change
+** without notice.  These values are for testing purposes only.
+** Applications should not use any of these parameters or the
+** [sqlite3_test_control()] interface.
+*/
+#define SQLITE_TESTCTRL_FIRST                    5
+#define SQLITE_TESTCTRL_PRNG_SAVE                5
+#define SQLITE_TESTCTRL_PRNG_RESTORE             6
+#define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
+#define SQLITE_TESTCTRL_FK_NO_ACTION             7
+#define SQLITE_TESTCTRL_BITVEC_TEST              8
+#define SQLITE_TESTCTRL_FAULT_INSTALL            9
+#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
+#define SQLITE_TESTCTRL_PENDING_BYTE            11
+#define SQLITE_TESTCTRL_ASSERT                  12
+#define SQLITE_TESTCTRL_ALWAYS                  13
+#define SQLITE_TESTCTRL_RESERVE                 14  /* NOT USED */
+#define SQLITE_TESTCTRL_JSON_SELFCHECK          14
+#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
+#define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
+#define SQLITE_TESTCTRL_GETOPT                  16
+#define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
+#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
+#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
+#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
+#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
+#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
+#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
+#define SQLITE_TESTCTRL_BYTEORDER               22
+#define SQLITE_TESTCTRL_ISINIT                  23
+#define SQLITE_TESTCTRL_SORTER_MMAP             24
+#define SQLITE_TESTCTRL_IMPOSTER                25
+#define SQLITE_TESTCTRL_PARSER_COVERAGE         26
+#define SQLITE_TESTCTRL_RESULT_INTREAL          27
+#define SQLITE_TESTCTRL_PRNG_SEED               28
+#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
+#define SQLITE_TESTCTRL_SEEK_COUNT              30
+#define SQLITE_TESTCTRL_TRACEFLAGS              31
+#define SQLITE_TESTCTRL_TUNE                    32
+#define SQLITE_TESTCTRL_LOGEST                  33
+#define SQLITE_TESTCTRL_USELONGDOUBLE           34  /* NOT USED */
+#define SQLITE_TESTCTRL_LAST                    34  /* Largest TESTCTRL */
+
+/*
+** CAPI3REF: SQL Keyword Checking
+**
+** These routines provide access to the set of SQL language keywords
+** recognized by SQLite.  Applications can uses these routines to determine
+** whether or not a specific identifier needs to be escaped (for example,
+** by enclosing in double-quotes) so as not to confuse the parser.
+**
+** The sqlite3_keyword_count() interface returns the number of distinct
+** keywords understood by SQLite.
+**
+** The sqlite3_keyword_name(N,Z,L) interface finds the 0-based N-th keyword and
+** makes *Z point to that keyword expressed as UTF8 and writes the number
+** of bytes in the keyword into *L.  The string that *Z points to is not
+** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
+** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
+** or L are NULL or invalid pointers then calls to
+** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
+**
+** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
+** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
+** if it is and zero if not.
+**
+** The parser used by SQLite is forgiving.  It is often possible to use
+** a keyword as an identifier as long as such use does not result in a
+** parsing ambiguity.  For example, the statement
+** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
+** creates a new table named "BEGIN" with three columns named
+** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
+** using keywords as identifiers.  Common techniques used to avoid keyword
+** name collisions include:
+** <ul>
+** <li> Put all identifier names inside double-quotes.  This is the official
+**      SQL way to escape identifier names.
+** <li> Put identifier names inside [...].  This is not standard SQL,
+**      but it is what SQL Server does and so lots of programmers use this
+**      technique.
+** <li> Begin every identifier with the letter "Z" as no SQL keywords start
+**      with "Z".
+** <li> Include a digit somewhere in every identifier name.
+** </ul>
+**
+** Note that the number of keywords understood by SQLite can depend on
+** compile-time options.  For example, "VACUUM" is not a keyword if
+** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
+** new keywords may be added to future releases of SQLite.
+*/
+SQLITE_API int sqlite3_keyword_count(void);
+SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
+SQLITE_API int sqlite3_keyword_check(const char*,int);
+
+/*
+** CAPI3REF: Dynamic String Object
+** KEYWORDS: {dynamic string}
+**
+** An instance of the sqlite3_str object contains a dynamically-sized
+** string under construction.
+**
+** The lifecycle of an sqlite3_str object is as follows:
+** <ol>
+** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
+** <li> ^Text is appended to the sqlite3_str object using various
+** methods, such as [sqlite3_str_appendf()].
+** <li> ^The sqlite3_str object is destroyed and the string it created
+** is returned using the [sqlite3_str_finish()] interface.
+** </ol>
+*/
+typedef struct sqlite3_str sqlite3_str;
+
+/*
+** CAPI3REF: Create A New Dynamic String Object
+** CONSTRUCTOR: sqlite3_str
+**
+** ^The [sqlite3_str_new(D)] interface allocates and initializes
+** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
+** [sqlite3_str_new()] must be freed by a subsequent call to
+** [sqlite3_str_finish(X)].
+**
+** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
+** valid [sqlite3_str] object, though in the event of an out-of-memory
+** error the returned object might be a special singleton that will
+** silently reject new text, always return SQLITE_NOMEM from
+** [sqlite3_str_errcode()], always return 0 for
+** [sqlite3_str_length()], and always return NULL from
+** [sqlite3_str_finish(X)].  It is always safe to use the value
+** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
+** to any of the other [sqlite3_str] methods.
+**
+** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
+** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
+** length of the string contained in the [sqlite3_str] object will be
+** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
+** of [SQLITE_MAX_LENGTH].
+*/
+SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
+
+/*
+** CAPI3REF: Finalize A Dynamic String
+** DESTRUCTOR: sqlite3_str
+**
+** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
+** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
+** that contains the constructed string.  The calling application should
+** pass the returned value to [sqlite3_free()] to avoid a memory leak.
+** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
+** errors were encountered during construction of the string.  ^The
+** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
+** string in [sqlite3_str] object X is zero bytes long.
+*/
+SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
+
+/*
+** CAPI3REF: Add Content To A Dynamic String
+** METHOD: sqlite3_str
+**
+** These interfaces add content to an sqlite3_str object previously obtained
+** from [sqlite3_str_new()].
+**
+** ^The [sqlite3_str_appendf(X,F,...)] and
+** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
+** functionality of SQLite to append formatted text onto the end of
+** [sqlite3_str] object X.
+**
+** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
+** onto the end of the [sqlite3_str] object X.  N must be non-negative.
+** S must contain at least N non-zero bytes of content.  To append a
+** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
+** method instead.
+**
+** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
+** zero-terminated string S onto the end of [sqlite3_str] object X.
+**
+** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
+** single-byte character C onto the end of [sqlite3_str] object X.
+** ^This method can be used, for example, to add whitespace indentation.
+**
+** ^The [sqlite3_str_reset(X)] method resets the string under construction
+** inside [sqlite3_str] object X back to zero bytes in length.
+**
+** These methods do not return a result code.  ^If an error occurs, that fact
+** is recorded in the [sqlite3_str] object and can be recovered by a
+** subsequent call to [sqlite3_str_errcode(X)].
+*/
+SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
+SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
+SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
+SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
+SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
+SQLITE_API void sqlite3_str_reset(sqlite3_str*);
+
+/*
+** CAPI3REF: Status Of A Dynamic String
+** METHOD: sqlite3_str
+**
+** These interfaces return the current status of an [sqlite3_str] object.
+**
+** ^If any prior errors have occurred while constructing the dynamic string
+** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
+** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
+** [SQLITE_NOMEM] following any out-of-memory error, or
+** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
+** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
+**
+** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
+** of the dynamic string under construction in [sqlite3_str] object X.
+** ^The length returned by [sqlite3_str_length(X)] does not include the
+** zero-termination byte.
+**
+** ^The [sqlite3_str_value(X)] method returns a pointer to the current
+** content of the dynamic string under construction in X.  The value
+** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
+** and might be freed or altered by any subsequent method on the same
+** [sqlite3_str] object.  Applications must not used the pointer returned
+** [sqlite3_str_value(X)] after any subsequent method call on the same
+** object.  ^Applications may change the content of the string returned
+** by [sqlite3_str_value(X)] as long as they do not write into any bytes
+** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
+** write any byte after any subsequent sqlite3_str method call.
+*/
+SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
+SQLITE_API int sqlite3_str_length(sqlite3_str*);
+SQLITE_API char *sqlite3_str_value(sqlite3_str*);
+
+/*
+** CAPI3REF: SQLite Runtime Status
+**
+** ^These interfaces are used to retrieve runtime status information
+** about the performance of SQLite, and optionally to reset various
+** highwater marks.  ^The first argument is an integer code for
+** the specific parameter to measure.  ^(Recognized integer codes
+** are of the form [status parameters | SQLITE_STATUS_...].)^
+** ^The current value of the parameter is returned into *pCurrent.
+** ^The highest recorded value is returned in *pHighwater.  ^If the
+** resetFlag is true, then the highest record value is reset after
+** *pHighwater is written.  ^(Some parameters do not record the highest
+** value.  For those parameters
+** nothing is written into *pHighwater and the resetFlag is ignored.)^
+** ^(Other parameters record only the highwater mark and not the current
+** value.  For these latter parameters nothing is written into *pCurrent.)^
+**
+** ^The sqlite3_status() and sqlite3_status64() routines return
+** SQLITE_OK on success and a non-zero [error code] on failure.
+**
+** If either the current value or the highwater mark is too large to
+** be represented by a 32-bit integer, then the values returned by
+** sqlite3_status() are undefined.
+**
+** See also: [sqlite3_db_status()]
+*/
+SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
+SQLITE_API int sqlite3_status64(
+  int op,
+  sqlite3_int64 *pCurrent,
+  sqlite3_int64 *pHighwater,
+  int resetFlag
+);
+
+
+/*
+** CAPI3REF: Status Parameters
+** KEYWORDS: {status parameters}
+**
+** These integer constants designate various run-time status parameters
+** that can be returned by [sqlite3_status()].
+**
+** <dl>
+** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
+** <dd>This parameter is the current amount of memory checked out
+** using [sqlite3_malloc()], either directly or indirectly.  The
+** figure includes calls made to [sqlite3_malloc()] by the application
+** and internal memory usage by the SQLite library.  Auxiliary page-cache
+** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
+** this parameter.  The amount returned is the sum of the allocation
+** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
+**
+** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
+** <dd>This parameter records the largest memory allocation request
+** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
+** internal equivalents).  Only the value returned in the
+** *pHighwater parameter to [sqlite3_status()] is of interest.
+** The value written into the *pCurrent parameter is undefined.</dd>)^
+**
+** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
+** <dd>This parameter records the number of separate memory allocations
+** currently checked out.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
+** <dd>This parameter returns the number of pages used out of the
+** [pagecache memory allocator] that was configured using
+** [SQLITE_CONFIG_PAGECACHE].  The
+** value returned is in pages, not in bytes.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
+** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
+** <dd>This parameter returns the number of bytes of page cache
+** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
+** buffer and where forced to overflow to [sqlite3_malloc()].  The
+** returned value includes allocations that overflowed because they
+** where too large (they were larger than the "sz" parameter to
+** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
+** no space was left in the page cache.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
+** <dd>This parameter records the largest memory allocation request
+** handed to the [pagecache memory allocator].  Only the value returned in the
+** *pHighwater parameter to [sqlite3_status()] is of interest.
+** The value written into the *pCurrent parameter is undefined.</dd>)^
+**
+** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
+** <dd>The *pHighwater parameter records the deepest parser stack.
+** The *pCurrent value is undefined.  The *pHighwater value is only
+** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
+** </dl>
+**
+** New status parameters may be added from time to time.
+*/
+#define SQLITE_STATUS_MEMORY_USED          0
+#define SQLITE_STATUS_PAGECACHE_USED       1
+#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
+#define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
+#define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
+#define SQLITE_STATUS_MALLOC_SIZE          5
+#define SQLITE_STATUS_PARSER_STACK         6
+#define SQLITE_STATUS_PAGECACHE_SIZE       7
+#define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
+#define SQLITE_STATUS_MALLOC_COUNT         9
+
+/*
+** CAPI3REF: Database Connection Status
+** METHOD: sqlite3
+**
+** ^This interface is used to retrieve runtime status information
+** about a single [database connection].  ^The first argument is the
+** database connection object to be interrogated.  ^The second argument
+** is an integer constant, taken from the set of
+** [SQLITE_DBSTATUS options], that
+** determines the parameter to interrogate.  The set of
+** [SQLITE_DBSTATUS options] is likely
+** to grow in future releases of SQLite.
+**
+** ^The current value of the requested parameter is written into *pCur
+** and the highest instantaneous value is written into *pHiwtr.  ^If
+** the resetFlg is true, then the highest instantaneous value is
+** reset back down to the current value.
+**
+** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
+** non-zero [error code] on failure.
+**
+** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
+*/
+SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
+
+/*
+** CAPI3REF: Status Parameters for database connections
+** KEYWORDS: {SQLITE_DBSTATUS options}
+**
+** These constants are the available integer "verbs" that can be passed as
+** the second argument to the [sqlite3_db_status()] interface.
+**
+** New verbs may be added in future releases of SQLite. Existing verbs
+** might be discontinued. Applications should check the return code from
+** [sqlite3_db_status()] to make sure that the call worked.
+** The [sqlite3_db_status()] interface will return a non-zero error code
+** if a discontinued or unsupported verb is invoked.
+**
+** <dl>
+** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
+** <dd>This parameter returns the number of lookaside memory slots currently
+** checked out.</dd>)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
+** <dd>This parameter returns the number of malloc attempts that were
+** satisfied using lookaside memory. Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to the amount of
+** memory requested being larger than the lookaside slot size.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to all lookaside
+** memory already being in use.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** memory used by all pager caches associated with the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
+** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
+** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
+** pager cache is shared between two or more connections the bytes of heap
+** memory used by that pager cache is divided evenly between the attached
+** connections.)^  In other words, if none of the pager caches associated
+** with the database connection are shared, this request returns the same
+** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
+** shared, the value returned by this call will be smaller than that returned
+** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
+** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
+**
+** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** memory used to store the schema for all databases associated
+** with the connection - main, temp, and any [ATTACH]-ed databases.)^
+** ^The full amount of memory used by the schemas is reported, even if the
+** schema memory is shared with other database connections due to
+** [shared cache mode] being enabled.
+** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** and lookaside memory used by all prepared statements associated with
+** the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
+** <dd>This parameter returns the number of pager cache hits that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
+** <dd>This parameter returns the number of pager cache misses that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk. Specifically, the number of pages written to the
+** wal file in wal mode databases, or the number of pages written to the
+** database file in rollback mode databases. Any pages written as part of
+** transaction rollback or database recovery operations are not included.
+** If an IO or other error occurs while writing a page to disk, the effect
+** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
+** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk in the middle of a transaction due to the page
+** cache overflowing. Transactions are more efficient if they are written
+** to disk all at once. When pages spill mid-transaction, that introduces
+** additional overhead. This parameter can be used help identify
+** inefficiencies that can be resolved by increasing the cache size.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
+** <dd>This parameter returns zero for the current value if and only if
+** all foreign key constraints (deferred or immediate) have been
+** resolved.)^  ^The highwater mark is always 0.
+** </dd>
+** </dl>
+*/
+#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
+#define SQLITE_DBSTATUS_CACHE_USED           1
+#define SQLITE_DBSTATUS_SCHEMA_USED          2
+#define SQLITE_DBSTATUS_STMT_USED            3
+#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
+#define SQLITE_DBSTATUS_CACHE_HIT            7
+#define SQLITE_DBSTATUS_CACHE_MISS           8
+#define SQLITE_DBSTATUS_CACHE_WRITE          9
+#define SQLITE_DBSTATUS_DEFERRED_FKS        10
+#define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
+#define SQLITE_DBSTATUS_CACHE_SPILL         12
+#define SQLITE_DBSTATUS_MAX                 12   /* Largest defined DBSTATUS */
+
+
+/*
+** CAPI3REF: Prepared Statement Status
+** METHOD: sqlite3_stmt
+**
+** ^(Each prepared statement maintains various
+** [SQLITE_STMTSTATUS counters] that measure the number
+** of times it has performed specific operations.)^  These counters can
+** be used to monitor the performance characteristics of the prepared
+** statements.  For example, if the number of table steps greatly exceeds
+** the number of table searches or result rows, that would tend to indicate
+** that the prepared statement is using a full table scan rather than
+** an index.
+**
+** ^(This interface is used to retrieve and reset counter values from
+** a [prepared statement].  The first argument is the prepared statement
+** object to be interrogated.  The second argument
+** is an integer code for a specific [SQLITE_STMTSTATUS counter]
+** to be interrogated.)^
+** ^The current value of the requested counter is returned.
+** ^If the resetFlg is true, then the counter is reset to zero after this
+** interface call returns.
+**
+** See also: [sqlite3_status()] and [sqlite3_db_status()].
+*/
+SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
+
+/*
+** CAPI3REF: Status Parameters for prepared statements
+** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
+**
+** These preprocessor macros define integer codes that name counter
+** values associated with the [sqlite3_stmt_status()] interface.
+** The meanings of the various counters are as follows:
+**
+** <dl>
+** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
+** <dd>^This is the number of times that SQLite has stepped forward in
+** a table as part of a full table scan.  Large numbers for this counter
+** may indicate opportunities for performance improvement through
+** careful use of indices.</dd>
+**
+** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
+** <dd>^This is the number of sort operations that have occurred.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance through careful use of indices.</dd>
+**
+** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
+** <dd>^This is the number of rows inserted into transient indices that
+** were created automatically in order to help joins run faster.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance by adding permanent indices that do not
+** need to be reinitialized each time the statement is run.</dd>
+**
+** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
+** <dd>^This is the number of virtual machine operations executed
+** by the prepared statement if that number is less than or equal
+** to 2147483647.  The number of virtual machine operations can be
+** used as a proxy for the total work done by the prepared statement.
+** If the number of virtual machine operations exceeds 2147483647
+** then the value returned by this statement status code is undefined.
+**
+** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
+** <dd>^This is the number of times that the prepare statement has been
+** automatically regenerated due to schema changes or changes to
+** [bound parameters] that might affect the query plan.
+**
+** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
+** <dd>^This is the number of times that the prepared statement has
+** been run.  A single "run" for the purposes of this counter is one
+** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
+** The counter is incremented on the first [sqlite3_step()] call of each
+** cycle.
+**
+** [[SQLITE_STMTSTATUS_FILTER_MISS]]
+** [[SQLITE_STMTSTATUS_FILTER HIT]]
+** <dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
+** SQLITE_STMTSTATUS_FILTER_MISS</dt>
+** <dd>^SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
+** step was bypassed because a Bloom filter returned not-found.  The
+** corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
+** times that the Bloom filter returned a find, and thus the join step
+** had to be processed as normal.
+**
+** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
+** <dd>^This is the approximate number of bytes of heap memory
+** used to store the prepared statement.  ^This value is not actually
+** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
+** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
+** </dd>
+** </dl>
+*/
+#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
+#define SQLITE_STMTSTATUS_SORT              2
+#define SQLITE_STMTSTATUS_AUTOINDEX         3
+#define SQLITE_STMTSTATUS_VM_STEP           4
+#define SQLITE_STMTSTATUS_REPREPARE         5
+#define SQLITE_STMTSTATUS_RUN               6
+#define SQLITE_STMTSTATUS_FILTER_MISS       7
+#define SQLITE_STMTSTATUS_FILTER_HIT        8
+#define SQLITE_STMTSTATUS_MEMUSED           99
+
+/*
+** CAPI3REF: Custom Page Cache Object
+**
+** The sqlite3_pcache type is opaque.  It is implemented by
+** the pluggable module.  The SQLite core has no knowledge of
+** its size or internal structure and never deals with the
+** sqlite3_pcache object except by holding and passing pointers
+** to the object.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache sqlite3_pcache;
+
+/*
+** CAPI3REF: Custom Page Cache Object
+**
+** The sqlite3_pcache_page object represents a single page in the
+** page cache.  The page cache will allocate instances of this
+** object.  Various methods of the page cache use pointers to instances
+** of this object as parameters or as their return value.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache_page sqlite3_pcache_page;
+struct sqlite3_pcache_page {
+  void *pBuf;        /* The content of the page */
+  void *pExtra;      /* Extra information associated with the page */
+};
+
+/*
+** CAPI3REF: Application Defined Page Cache.
+** KEYWORDS: {page cache}
+**
+** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
+** register an alternative page cache implementation by passing in an
+** instance of the sqlite3_pcache_methods2 structure.)^
+** In many applications, most of the heap memory allocated by
+** SQLite is used for the page cache.
+** By implementing a
+** custom page cache using this API, an application can better control
+** the amount of memory consumed by SQLite, the way in which
+** that memory is allocated and released, and the policies used to
+** determine exactly which parts of a database file are cached and for
+** how long.
+**
+** The alternative page cache mechanism is an
+** extreme measure that is only needed by the most demanding applications.
+** The built-in page cache is recommended for most uses.
+**
+** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
+** internal buffer by SQLite within the call to [sqlite3_config].  Hence
+** the application may discard the parameter after the call to
+** [sqlite3_config()] returns.)^
+**
+** [[the xInit() page cache method]]
+** ^(The xInit() method is called once for each effective
+** call to [sqlite3_initialize()])^
+** (usually only once during the lifetime of the process). ^(The xInit()
+** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
+** The intent of the xInit() method is to set up global data structures
+** required by the custom page cache implementation.
+** ^(If the xInit() method is NULL, then the
+** built-in default page cache is used instead of the application defined
+** page cache.)^
+**
+** [[the xShutdown() page cache method]]
+** ^The xShutdown() method is called by [sqlite3_shutdown()].
+** It can be used to clean up
+** any outstanding resources before process shutdown, if required.
+** ^The xShutdown() method may be NULL.
+**
+** ^SQLite automatically serializes calls to the xInit method,
+** so the xInit method need not be threadsafe.  ^The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  All other methods must be threadsafe
+** in multithreaded applications.
+**
+** ^SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+**
+** [[the xCreate() page cache methods]]
+** ^SQLite invokes the xCreate() method to construct a new cache instance.
+** SQLite will typically create one cache instance for each open database file,
+** though this is not guaranteed. ^The
+** first parameter, szPage, is the size in bytes of the pages that must
+** be allocated by the cache.  ^szPage will always a power of two.  ^The
+** second parameter szExtra is a number of bytes of extra storage
+** associated with each page cache entry.  ^The szExtra parameter will
+** a number less than 250.  SQLite will use the
+** extra szExtra bytes on each page to store metadata about the underlying
+** database page on disk.  The value passed into szExtra depends
+** on the SQLite version, the target platform, and how SQLite was compiled.
+** ^The third argument to xCreate(), bPurgeable, is true if the cache being
+** created will be used to cache database pages of a file stored on disk, or
+** false if it is used for an in-memory database. The cache implementation
+** does not have to do anything special based with the value of bPurgeable;
+** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
+** never invoke xUnpin() except to deliberately delete a page.
+** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
+** false will always have the "discard" flag set to true.
+** ^Hence, a cache created with bPurgeable false will
+** never contain any unpinned pages.
+**
+** [[the xCachesize() page cache method]]
+** ^(The xCachesize() method may be called at any time by SQLite to set the
+** suggested maximum cache-size (number of pages stored by) the cache
+** instance passed as the first argument. This is the value configured using
+** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
+** parameter, the implementation is not required to do anything with this
+** value; it is advisory only.
+**
+** [[the xPagecount() page cache methods]]
+** The xPagecount() method must return the number of pages currently
+** stored in the cache, both pinned and unpinned.
+**
+** [[the xFetch() page cache methods]]
+** The xFetch() method locates a page in the cache and returns a pointer to
+** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
+** The pBuf element of the returned sqlite3_pcache_page object will be a
+** pointer to a buffer of szPage bytes used to store the content of a
+** single database page.  The pExtra element of sqlite3_pcache_page will be
+** a pointer to the szExtra bytes of extra storage that SQLite has requested
+** for each entry in the page cache.
+**
+** The page to be fetched is determined by the key. ^The minimum key value
+** is 1.  After it has been retrieved using xFetch, the page is considered
+** to be "pinned".
+**
+** If the requested page is already in the page cache, then the page cache
+** implementation must return a pointer to the page buffer with its content
+** intact.  If the requested page is not already in the cache, then the
+** cache implementation should use the value of the createFlag
+** parameter to help it determined what action to take:
+**
+** <table border=1 width=85% align=center>
+** <tr><th> createFlag <th> Behavior when page is not already in cache
+** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
+** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
+**                 Otherwise return NULL.
+** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
+**                 NULL if allocating a new page is effectively impossible.
+** </table>
+**
+** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
+** will only use a createFlag of 2 after a prior call with a createFlag of 1
+** failed.)^  In between the xFetch() calls, SQLite may
+** attempt to unpin one or more cache pages by spilling the content of
+** pinned pages to disk and synching the operating system disk cache.
+**
+** [[the xUnpin() page cache method]]
+** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
+** as its second argument.  If the third parameter, discard, is non-zero,
+** then the page must be evicted from the cache.
+** ^If the discard parameter is
+** zero, then the page may be discarded or retained at the discretion of
+** page cache implementation. ^The page cache implementation
+** may choose to evict unpinned pages at any time.
+**
+** The cache must not perform any reference counting. A single
+** call to xUnpin() unpins the page regardless of the number of prior calls
+** to xFetch().
+**
+** [[the xRekey() page cache methods]]
+** The xRekey() method is used to change the key value associated with the
+** page passed as the second argument. If the cache
+** previously contains an entry associated with newKey, it must be
+** discarded. ^Any prior cache entry associated with newKey is guaranteed not
+** to be pinned.
+**
+** When SQLite calls the xTruncate() method, the cache must discard all
+** existing cache entries with page numbers (keys) greater than or equal
+** to the value of the iLimit parameter passed to xTruncate(). If any
+** of these pages are pinned, they are implicitly unpinned, meaning that
+** they can be safely discarded.
+**
+** [[the xDestroy() page cache method]]
+** ^The xDestroy() method is used to delete a cache allocated by xCreate().
+** All resources associated with the specified cache should be freed. ^After
+** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
+** handle invalid, and will not use it with any other sqlite3_pcache_methods2
+** functions.
+**
+** [[the xShrink() page cache method]]
+** ^SQLite invokes the xShrink() method when it wants the page cache to
+** free up as much of heap memory as possible.  The page cache implementation
+** is not obligated to free any memory, but well-behaved implementations should
+** do their best.
+*/
+typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
+struct sqlite3_pcache_methods2 {
+  int iVersion;
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
+  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
+      unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+  void (*xShrink)(sqlite3_pcache*);
+};
+
+/*
+** This is the obsolete pcache_methods object that has now been replaced
+** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
+** retained in the header file for backwards compatibility only.
+*/
+typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
+struct sqlite3_pcache_methods {
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
+  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+};
+
+
+/*
+** CAPI3REF: Online Backup Object
+**
+** The sqlite3_backup object records state information about an ongoing
+** online backup operation.  ^The sqlite3_backup object is created by
+** a call to [sqlite3_backup_init()] and is destroyed by a call to
+** [sqlite3_backup_finish()].
+**
+** See Also: [Using the SQLite Online Backup API]
+*/
+typedef struct sqlite3_backup sqlite3_backup;
+
+/*
+** CAPI3REF: Online Backup API.
+**
+** The backup API copies the content of one database into another.
+** It is useful either for creating backups of databases or
+** for copying in-memory databases to or from persistent files.
+**
+** See Also: [Using the SQLite Online Backup API]
+**
+** ^SQLite holds a write transaction open on the destination database file
+** for the duration of the backup operation.
+** ^The source database is read-locked only while it is being read;
+** it is not locked continuously for the entire backup operation.
+** ^Thus, the backup may be performed on a live source database without
+** preventing other database connections from
+** reading or writing to the source database while the backup is underway.
+**
+** ^(To perform a backup operation:
+**   <ol>
+**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
+**         backup,
+**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
+**         the data between the two databases, and finally
+**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
+**         associated with the backup operation.
+**   </ol>)^
+** There should be exactly one call to sqlite3_backup_finish() for each
+** successful call to sqlite3_backup_init().
+**
+** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
+**
+** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
+** [database connection] associated with the destination database
+** and the database name, respectively.
+** ^The database name is "main" for the main database, "temp" for the
+** temporary database, or the name specified after the AS keyword in
+** an [ATTACH] statement for an attached database.
+** ^The S and M arguments passed to
+** sqlite3_backup_init(D,N,S,M) identify the [database connection]
+** and database name of the source database, respectively.
+** ^The source and destination [database connections] (parameters S and D)
+** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
+** an error.
+**
+** ^A call to sqlite3_backup_init() will fail, returning NULL, if
+** there is already a read or read-write transaction open on the
+** destination database.
+**
+** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
+** returned and an error code and error message are stored in the
+** destination [database connection] D.
+** ^The error code and message for the failed call to sqlite3_backup_init()
+** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
+** [sqlite3_errmsg16()] functions.
+** ^A successful call to sqlite3_backup_init() returns a pointer to an
+** [sqlite3_backup] object.
+** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
+** sqlite3_backup_finish() functions to perform the specified backup
+** operation.
+**
+** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
+**
+** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
+** the source and destination databases specified by [sqlite3_backup] object B.
+** ^If N is negative, all remaining source pages are copied.
+** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
+** are still more pages to be copied, then the function returns [SQLITE_OK].
+** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
+** from source to destination, then it returns [SQLITE_DONE].
+** ^If an error occurs while running sqlite3_backup_step(B,N),
+** then an [error code] is returned. ^As well as [SQLITE_OK] and
+** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
+** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
+**
+** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
+** <ol>
+** <li> the destination database was opened read-only, or
+** <li> the destination database is using write-ahead-log journaling
+** and the destination and source page sizes differ, or
+** <li> the destination database is an in-memory database and the
+** destination and source page sizes differ.
+** </ol>)^
+**
+** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
+** the [sqlite3_busy_handler | busy-handler function]
+** is invoked (if one is specified). ^If the
+** busy-handler returns non-zero before the lock is available, then
+** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
+** sqlite3_backup_step() can be retried later. ^If the source
+** [database connection]
+** is being used to write to the source database when sqlite3_backup_step()
+** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
+** case the call to sqlite3_backup_step() can be retried later on. ^(If
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
+** [SQLITE_READONLY] is returned, then
+** there is no point in retrying the call to sqlite3_backup_step(). These
+** errors are considered fatal.)^  The application must accept
+** that the backup operation has failed and pass the backup operation handle
+** to the sqlite3_backup_finish() to release associated resources.
+**
+** ^The first call to sqlite3_backup_step() obtains an exclusive lock
+** on the destination file. ^The exclusive lock is not released until either
+** sqlite3_backup_finish() is called or the backup operation is complete
+** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
+** sqlite3_backup_step() obtains a [shared lock] on the source database that
+** lasts for the duration of the sqlite3_backup_step() call.
+** ^Because the source database is not locked between calls to
+** sqlite3_backup_step(), the source database may be modified mid-way
+** through the backup process.  ^If the source database is modified by an
+** external process or via a database connection other than the one being
+** used by the backup operation, then the backup will be automatically
+** restarted by the next call to sqlite3_backup_step(). ^If the source
+** database is modified by the using the same database connection as is used
+** by the backup operation, then the backup database is automatically
+** updated at the same time.
+**
+** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
+**
+** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
+** application wishes to abandon the backup operation, the application
+** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
+** ^The sqlite3_backup_finish() interfaces releases all
+** resources associated with the [sqlite3_backup] object.
+** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
+** active write-transaction on the destination database is rolled back.
+** The [sqlite3_backup] object is invalid
+** and may not be used following a call to sqlite3_backup_finish().
+**
+** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
+** sqlite3_backup_step() errors occurred, regardless or whether or not
+** sqlite3_backup_step() completed.
+** ^If an out-of-memory condition or IO error occurred during any prior
+** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
+** sqlite3_backup_finish() returns the corresponding [error code].
+**
+** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
+** is not a permanent error and does not affect the return value of
+** sqlite3_backup_finish().
+**
+** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
+** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
+**
+** ^The sqlite3_backup_remaining() routine returns the number of pages still
+** to be backed up at the conclusion of the most recent sqlite3_backup_step().
+** ^The sqlite3_backup_pagecount() routine returns the total number of pages
+** in the source database at the conclusion of the most recent
+** sqlite3_backup_step().
+** ^(The values returned by these functions are only updated by
+** sqlite3_backup_step(). If the source database is modified in a way that
+** changes the size of the source database or the number of pages remaining,
+** those changes are not reflected in the output of sqlite3_backup_pagecount()
+** and sqlite3_backup_remaining() until after the next
+** sqlite3_backup_step().)^
+**
+** <b>Concurrent Usage of Database Handles</b>
+**
+** ^The source [database connection] may be used by the application for other
+** purposes while a backup operation is underway or being initialized.
+** ^If SQLite is compiled and configured to support threadsafe database
+** connections, then the source database connection may be used concurrently
+** from within other threads.
+**
+** However, the application must guarantee that the destination
+** [database connection] is not passed to any other API (by any thread) after
+** sqlite3_backup_init() is called and before the corresponding call to
+** sqlite3_backup_finish().  SQLite does not currently check to see
+** if the application incorrectly accesses the destination [database connection]
+** and so no error code is reported, but the operations may malfunction
+** nevertheless.  Use of the destination database connection while a
+** backup is in progress might also cause a mutex deadlock.
+**
+** If running in [shared cache mode], the application must
+** guarantee that the shared cache used by the destination database
+** is not accessed while the backup is running. In practice this means
+** that the application must guarantee that the disk file being
+** backed up to is not accessed by any connection within the process,
+** not just the specific connection that was passed to sqlite3_backup_init().
+**
+** The [sqlite3_backup] object itself is partially threadsafe. Multiple
+** threads may safely make multiple concurrent calls to sqlite3_backup_step().
+** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
+** APIs are not strictly speaking threadsafe. If they are invoked at the
+** same time as another thread is invoking sqlite3_backup_step() it is
+** possible that they return invalid values.
+**
+** <b>Alternatives To Using The Backup API</b>
+**
+** Other techniques for safely creating a consistent backup of an SQLite
+** database include:
+**
+** <ul>
+** <li> The [VACUUM INTO] command.
+** <li> The [sqlite3_rsync] utility program.
+** </ul>
+*/
+SQLITE_API sqlite3_backup *sqlite3_backup_init(
+  sqlite3 *pDest,                        /* Destination database handle */
+  const char *zDestName,                 /* Destination database name */
+  sqlite3 *pSource,                      /* Source database handle */
+  const char *zSourceName                /* Source database name */
+);
+SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
+SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
+
+/*
+** CAPI3REF: Unlock Notification
+** METHOD: sqlite3
+**
+** ^When running in shared-cache mode, a database operation may fail with
+** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
+** individual tables within the shared-cache cannot be obtained. See
+** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
+** ^This API may be used to register a callback that SQLite will invoke
+** when the connection currently holding the required lock relinquishes it.
+** ^This API is only available if the library was compiled with the
+** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
+**
+** See Also: [Using the SQLite Unlock Notification Feature].
+**
+** ^Shared-cache locks are released when a database connection concludes
+** its current transaction, either by committing it or rolling it back.
+**
+** ^When a connection (known as the blocked connection) fails to obtain a
+** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
+** identity of the database connection (the blocking connection) that
+** has locked the required resource is stored internally. ^After an
+** application receives an SQLITE_LOCKED error, it may call the
+** sqlite3_unlock_notify() method with the blocked connection handle as
+** the first argument to register for a callback that will be invoked
+** when the blocking connections current transaction is concluded. ^The
+** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
+** call that concludes the blocking connection's transaction.
+**
+** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
+** there is a chance that the blocking connection will have already
+** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
+** If this happens, then the specified callback is invoked immediately,
+** from within the call to sqlite3_unlock_notify().)^
+**
+** ^If the blocked connection is attempting to obtain a write-lock on a
+** shared-cache table, and more than one other connection currently holds
+** a read-lock on the same table, then SQLite arbitrarily selects one of
+** the other connections to use as the blocking connection.
+**
+** ^(There may be at most one unlock-notify callback registered by a
+** blocked connection. If sqlite3_unlock_notify() is called when the
+** blocked connection already has a registered unlock-notify callback,
+** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
+** called with a NULL pointer as its second argument, then any existing
+** unlock-notify callback is canceled. ^The blocked connections
+** unlock-notify callback may also be canceled by closing the blocked
+** connection using [sqlite3_close()].
+**
+** The unlock-notify callback is not reentrant. If an application invokes
+** any sqlite3_xxx API functions from within an unlock-notify callback, a
+** crash or deadlock may be the result.
+**
+** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
+** returns SQLITE_OK.
+**
+** <b>Callback Invocation Details</b>
+**
+** When an unlock-notify callback is registered, the application provides a
+** single void* pointer that is passed to the callback when it is invoked.
+** However, the signature of the callback function allows SQLite to pass
+** it an array of void* context pointers. The first argument passed to
+** an unlock-notify callback is a pointer to an array of void* pointers,
+** and the second is the number of entries in the array.
+**
+** When a blocking connection's transaction is concluded, there may be
+** more than one blocked connection that has registered for an unlock-notify
+** callback. ^If two or more such blocked connections have specified the
+** same callback function, then instead of invoking the callback function
+** multiple times, it is invoked once with the set of void* context pointers
+** specified by the blocked connections bundled together into an array.
+** This gives the application an opportunity to prioritize any actions
+** related to the set of unblocked database connections.
+**
+** <b>Deadlock Detection</b>
+**
+** Assuming that after registering for an unlock-notify callback a
+** database waits for the callback to be issued before taking any further
+** action (a reasonable assumption), then using this API may cause the
+** application to deadlock. For example, if connection X is waiting for
+** connection Y's transaction to be concluded, and similarly connection
+** Y is waiting on connection X's transaction, then neither connection
+** will proceed and the system may remain deadlocked indefinitely.
+**
+** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
+** detection. ^If a given call to sqlite3_unlock_notify() would put the
+** system in a deadlocked state, then SQLITE_LOCKED is returned and no
+** unlock-notify callback is registered. The system is said to be in
+** a deadlocked state if connection A has registered for an unlock-notify
+** callback on the conclusion of connection B's transaction, and connection
+** B has itself registered for an unlock-notify callback when connection
+** A's transaction is concluded. ^Indirect deadlock is also detected, so
+** the system is also considered to be deadlocked if connection B has
+** registered for an unlock-notify callback on the conclusion of connection
+** C's transaction, where connection C is waiting on connection A. ^Any
+** number of levels of indirection are allowed.
+**
+** <b>The "DROP TABLE" Exception</b>
+**
+** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
+** always appropriate to call sqlite3_unlock_notify(). There is however,
+** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
+** SQLite checks if there are any currently executing SELECT statements
+** that belong to the same connection. If there are, SQLITE_LOCKED is
+** returned. In this case there is no "blocking connection", so invoking
+** sqlite3_unlock_notify() results in the unlock-notify callback being
+** invoked immediately. If the application then re-attempts the "DROP TABLE"
+** or "DROP INDEX" query, an infinite loop might be the result.
+**
+** One way around this problem is to check the extended error code returned
+** by an sqlite3_step() call. ^(If there is a blocking connection, then the
+** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
+** the special "DROP TABLE/INDEX" case, the extended error code is just
+** SQLITE_LOCKED.)^
+*/
+SQLITE_API int sqlite3_unlock_notify(
+  sqlite3 *pBlocked,                          /* Waiting connection */
+  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
+  void *pNotifyArg                            /* Argument to pass to xNotify */
+);
+
+
+/*
+** CAPI3REF: String Comparison
+**
+** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
+** and extensions to compare the contents of two buffers containing UTF-8
+** strings in a case-independent fashion, using the same definition of "case
+** independence" that SQLite uses internally when comparing identifiers.
+*/
+SQLITE_API int sqlite3_stricmp(const char *, const char *);
+SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
+
+/*
+** CAPI3REF: String Globbing
+*
+** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
+** string X matches the [GLOB] pattern P.
+** ^The definition of [GLOB] pattern matching used in
+** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
+** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
+** is case sensitive.
+**
+** Note that this routine returns zero on a match and non-zero if the strings
+** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
+**
+** See also: [sqlite3_strlike()].
+*/
+SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
+
+/*
+** CAPI3REF: String LIKE Matching
+*
+** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
+** string X matches the [LIKE] pattern P with escape character E.
+** ^The definition of [LIKE] pattern matching used in
+** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
+** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
+** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
+** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
+** insensitive - equivalent upper and lower case ASCII characters match
+** one another.
+**
+** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
+** only ASCII characters are case folded.
+**
+** Note that this routine returns zero on a match and non-zero if the strings
+** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
+**
+** See also: [sqlite3_strglob()].
+*/
+SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
+
+/*
+** CAPI3REF: Error Logging Interface
+**
+** ^The [sqlite3_log()] interface writes a message into the [error log]
+** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
+** ^If logging is enabled, the zFormat string and subsequent arguments are
+** used with [sqlite3_snprintf()] to generate the final output string.
+**
+** The sqlite3_log() interface is intended for use by extensions such as
+** virtual tables, collating functions, and SQL functions.  While there is
+** nothing to prevent an application from calling sqlite3_log(), doing so
+** is considered bad form.
+**
+** The zFormat string must not be NULL.
+**
+** To avoid deadlocks and other threading problems, the sqlite3_log() routine
+** will not use dynamically allocated memory.  The log message is stored in
+** a fixed-length buffer on the stack.  If the log message is longer than
+** a few hundred characters, it will be truncated to the length of the
+** buffer.
+*/
+SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
+
+/*
+** CAPI3REF: Write-Ahead Log Commit Hook
+** METHOD: sqlite3
+**
+** ^The [sqlite3_wal_hook()] function is used to register a callback that
+** is invoked each time data is committed to a database in wal mode.
+**
+** ^(The callback is invoked by SQLite after the commit has taken place and
+** the associated write-lock on the database released)^, so the implementation
+** may read, write or [checkpoint] the database as required.
+**
+** ^The first parameter passed to the callback function when it is invoked
+** is a copy of the third parameter passed to sqlite3_wal_hook() when
+** registering the callback. ^The second is a copy of the database handle.
+** ^The third parameter is the name of the database that was written to -
+** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
+** is the number of pages currently in the write-ahead log file,
+** including those that were just committed.
+**
+** The callback function should normally return [SQLITE_OK].  ^If an error
+** code is returned, that error will propagate back up through the
+** SQLite code base to cause the statement that provoked the callback
+** to report an error, though the commit will have still occurred. If the
+** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
+** that does not correspond to any valid SQLite error code, the results
+** are undefined.
+**
+** A single database handle may have at most a single write-ahead log callback
+** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
+** previously registered write-ahead log callback. ^The return value is
+** a copy of the third parameter from the previous call, if any, or 0.
+** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
+** overwrite any prior [sqlite3_wal_hook()] settings.
+*/
+SQLITE_API void *sqlite3_wal_hook(
+  sqlite3*,
+  int(*)(void *,sqlite3*,const char*,int),
+  void*
+);
+
+/*
+** CAPI3REF: Configure an auto-checkpoint
+** METHOD: sqlite3
+**
+** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
+** [sqlite3_wal_hook()] that causes any database on [database connection] D
+** to automatically [checkpoint]
+** after committing a transaction if there are N or
+** more frames in the [write-ahead log] file.  ^Passing zero or
+** a negative value as the nFrame parameter disables automatic
+** checkpoints entirely.
+**
+** ^The callback registered by this function replaces any existing callback
+** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
+** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
+** configured by this function.
+**
+** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
+** from SQL.
+**
+** ^Checkpoints initiated by this mechanism are
+** [sqlite3_wal_checkpoint_v2|PASSIVE].
+**
+** ^Every new [database connection] defaults to having the auto-checkpoint
+** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
+** pages.  The use of this interface
+** is only necessary if the default setting is found to be suboptimal
+** for a particular application.
+*/
+SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Checkpoint a database
+** METHOD: sqlite3
+**
+** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
+** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
+**
+** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
+** [write-ahead log] for database X on [database connection] D to be
+** transferred into the database file and for the write-ahead log to
+** be reset.  See the [checkpointing] documentation for addition
+** information.
+**
+** This interface used to be the only way to cause a checkpoint to
+** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
+** interface was added.  This interface is retained for backwards
+** compatibility and as a convenience for applications that need to manually
+** start a callback but which do not need the full power (and corresponding
+** complication) of [sqlite3_wal_checkpoint_v2()].
+*/
+SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Checkpoint a database
+** METHOD: sqlite3
+**
+** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
+** operation on database X of [database connection] D in mode M.  Status
+** information is written back into integers pointed to by L and C.)^
+** ^(The M parameter must be a valid [checkpoint mode]:)^
+**
+** <dl>
+** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
+**   ^Checkpoint as many frames as possible without waiting for any database
+**   readers or writers to finish, then sync the database file if all frames
+**   in the log were checkpointed. ^The [busy-handler callback]
+**   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
+**   ^On the other hand, passive mode might leave the checkpoint unfinished
+**   if there are concurrent readers or writers.
+**
+** <dt>SQLITE_CHECKPOINT_FULL<dd>
+**   ^This mode blocks (it invokes the
+**   [sqlite3_busy_handler|busy-handler callback]) until there is no
+**   database writer and all readers are reading from the most recent database
+**   snapshot. ^It then checkpoints all frames in the log file and syncs the
+**   database file. ^This mode blocks new database writers while it is pending,
+**   but new database readers are allowed to continue unimpeded.
+**
+** <dt>SQLITE_CHECKPOINT_RESTART<dd>
+**   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
+**   that after checkpointing the log file it blocks (calls the
+**   [busy-handler callback])
+**   until all readers are reading from the database file only. ^This ensures
+**   that the next writer will restart the log file from the beginning.
+**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
+**   database writer attempts while it is pending, but does not impede readers.
+**
+** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
+**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
+**   addition that it also truncates the log file to zero bytes just prior
+**   to a successful return.
+** </dl>
+**
+** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
+** the log file or to -1 if the checkpoint could not run because
+** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
+** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
+** log file (including any that were already checkpointed before the function
+** was called) or to -1 if the checkpoint could not run due to an error or
+** because the database is not in WAL mode. ^Note that upon successful
+** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
+** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
+**
+** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
+** any other process is running a checkpoint operation at the same time, the
+** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
+** busy-handler configured, it will not be invoked in this case.
+**
+** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
+** exclusive "writer" lock on the database file. ^If the writer lock cannot be
+** obtained immediately, and a busy-handler is configured, it is invoked and
+** the writer lock retried until either the busy-handler returns 0 or the lock
+** is successfully obtained. ^The busy-handler is also invoked while waiting for
+** database readers as described above. ^If the busy-handler returns 0 before
+** the writer lock is obtained or while waiting for database readers, the
+** checkpoint operation proceeds from that point in the same way as
+** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
+** without blocking any further. ^SQLITE_BUSY is returned in this case.
+**
+** ^If parameter zDb is NULL or points to a zero length string, then the
+** specified operation is attempted on all WAL databases [attached] to
+** [database connection] db.  In this case the
+** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
+** an SQLITE_BUSY error is encountered when processing one or more of the
+** attached WAL databases, the operation is still attempted on any remaining
+** attached databases and SQLITE_BUSY is returned at the end. ^If any other
+** error occurs while processing an attached database, processing is abandoned
+** and the error code is returned to the caller immediately. ^If no error
+** (SQLITE_BUSY or otherwise) is encountered while processing the attached
+** databases, SQLITE_OK is returned.
+**
+** ^If database zDb is the name of an attached database that is not in WAL
+** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
+** zDb is not NULL (or a zero length string) and is not the name of any
+** attached database, SQLITE_ERROR is returned to the caller.
+**
+** ^Unless it returns SQLITE_MISUSE,
+** the sqlite3_wal_checkpoint_v2() interface
+** sets the error information that is queried by
+** [sqlite3_errcode()] and [sqlite3_errmsg()].
+**
+** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
+** from SQL.
+*/
+SQLITE_API int sqlite3_wal_checkpoint_v2(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of attached database (or NULL) */
+  int eMode,                      /* SQLITE_CHECKPOINT_* value */
+  int *pnLog,                     /* OUT: Size of WAL log in frames */
+  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
+);
+
+/*
+** CAPI3REF: Checkpoint Mode Values
+** KEYWORDS: {checkpoint mode}
+**
+** These constants define all valid values for the "checkpoint mode" passed
+** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
+** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
+** meaning of each of these checkpoint modes.
+*/
+#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
+#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
+#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for readers */
+#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
+
+/*
+** CAPI3REF: Virtual Table Interface Configuration
+**
+** This function may be called by either the [xConnect] or [xCreate] method
+** of a [virtual table] implementation to configure
+** various facets of the virtual table interface.
+**
+** If this interface is invoked outside the context of an xConnect or
+** xCreate virtual table method then the behavior is undefined.
+**
+** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
+** [database connection] in which the virtual table is being created and
+** which is passed in as the first argument to the [xConnect] or [xCreate]
+** method that is invoking sqlite3_vtab_config().  The C parameter is one
+** of the [virtual table configuration options].  The presence and meaning
+** of parameters after C depend on which [virtual table configuration option]
+** is used.
+*/
+SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Virtual Table Configuration Options
+** KEYWORDS: {virtual table configuration options}
+** KEYWORDS: {virtual table configuration option}
+**
+** These macros define the various options to the
+** [sqlite3_vtab_config()] interface that [virtual table] implementations
+** can use to customize and optimize their behavior.
+**
+** <dl>
+** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
+** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
+** where X is an integer.  If X is zero, then the [virtual table] whose
+** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
+** support constraints.  In this configuration (which is the default) if
+** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
+** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
+** specified as part of the users SQL statement, regardless of the actual
+** ON CONFLICT mode specified.
+**
+** If X is non-zero, then the virtual table implementation guarantees
+** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
+** any modifications to internal or persistent data structures have been made.
+** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
+** is able to roll back a statement or database transaction, and abandon
+** or continue processing the current SQL statement as appropriate.
+** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
+** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
+** had been ABORT.
+**
+** Virtual table implementations that are required to handle OR REPLACE
+** must do so within the [xUpdate] method. If a call to the
+** [sqlite3_vtab_on_conflict()] function indicates that the current ON
+** CONFLICT policy is REPLACE, the virtual table implementation should
+** silently replace the appropriate rows within the xUpdate callback and
+** return SQLITE_OK. Or, if this is not possible, it may return
+** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
+** constraint handling.
+** </dd>
+**
+** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** prohibits that virtual table from being used from within triggers and
+** views.
+** </dd>
+**
+** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** identify that virtual table as being safe to use from within triggers
+** and views.  Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
+** virtual table can do no serious harm even if it is controlled by a
+** malicious hacker.  Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
+** flag unless absolutely necessary.
+** </dd>
+**
+** [[SQLITE_VTAB_USES_ALL_SCHEMAS]]<dt>SQLITE_VTAB_USES_ALL_SCHEMAS</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_USES_ALL_SCHEMA) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** instruct the query planner to begin at least a read transaction on
+** all schemas ("main", "temp", and any ATTACH-ed databases) whenever the
+** virtual table is used.
+** </dd>
+** </dl>
+*/
+#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
+#define SQLITE_VTAB_INNOCUOUS          2
+#define SQLITE_VTAB_DIRECTONLY         3
+#define SQLITE_VTAB_USES_ALL_SCHEMAS   4
+
+/*
+** CAPI3REF: Determine The Virtual Table Conflict Policy
+**
+** This function may only be called from within a call to the [xUpdate] method
+** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
+** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
+** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
+** of the SQL statement that triggered the call to the [xUpdate] method of the
+** [virtual table].
+*/
+SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
+
+/*
+** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
+**
+** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
+** method of a [virtual table], then it might return true if the
+** column is being fetched as part of an UPDATE operation during which the
+** column value will not change.  The virtual table implementation can use
+** this hint as permission to substitute a return value that is less
+** expensive to compute and that the corresponding
+** [xUpdate] method understands as a "no-change" value.
+**
+** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
+** the column is not changed by the UPDATE statement, then the xColumn
+** method can optionally return without setting a result, without calling
+** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
+** In that case, [sqlite3_value_nochange(X)] will return true for the
+** same column in the [xUpdate] method.
+**
+** The sqlite3_vtab_nochange() routine is an optimization.  Virtual table
+** implementations should continue to give a correct answer even if the
+** sqlite3_vtab_nochange() interface were to always return false.  In the
+** current implementation, the sqlite3_vtab_nochange() interface does always
+** returns false for the enhanced [UPDATE FROM] statement.
+*/
+SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
+
+/*
+** CAPI3REF: Determine The Collation For a Virtual Table Constraint
+** METHOD: sqlite3_index_info
+**
+** This function may only be called from within a call to the [xBestIndex]
+** method of a [virtual table].  This function returns a pointer to a string
+** that is the name of the appropriate collation sequence to use for text
+** comparisons on the constraint identified by its arguments.
+**
+** The first argument must be the pointer to the [sqlite3_index_info] object
+** that is the first parameter to the xBestIndex() method. The second argument
+** must be an index into the aConstraint[] array belonging to the
+** sqlite3_index_info structure passed to xBestIndex.
+**
+** Important:
+** The first parameter must be the same pointer that is passed into the
+** xBestMethod() method.  The first parameter may not be a pointer to a
+** different [sqlite3_index_info] object, even an exact copy.
+**
+** The return value is computed as follows:
+**
+** <ol>
+** <li><p> If the constraint comes from a WHERE clause expression that contains
+**         a [COLLATE operator], then the name of the collation specified by
+**         that COLLATE operator is returned.
+** <li><p> If there is no COLLATE operator, but the column that is the subject
+**         of the constraint specifies an alternative collating sequence via
+**         a [COLLATE clause] on the column definition within the CREATE TABLE
+**         statement that was passed into [sqlite3_declare_vtab()], then the
+**         name of that alternative collating sequence is returned.
+** <li><p> Otherwise, "BINARY" is returned.
+** </ol>
+*/
+SQLITE_API const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
+
+/*
+** CAPI3REF: Determine if a virtual table query is DISTINCT
+** METHOD: sqlite3_index_info
+**
+** This API may only be used from within an [xBestIndex|xBestIndex method]
+** of a [virtual table] implementation. The result of calling this
+** interface from outside of xBestIndex() is undefined and probably harmful.
+**
+** ^The sqlite3_vtab_distinct() interface returns an integer between 0 and
+** 3.  The integer returned by sqlite3_vtab_distinct()
+** gives the virtual table additional information about how the query
+** planner wants the output to be ordered. As long as the virtual table
+** can meet the ordering requirements of the query planner, it may set
+** the "orderByConsumed" flag.
+**
+** <ol><li value="0"><p>
+** ^If the sqlite3_vtab_distinct() interface returns 0, that means
+** that the query planner needs the virtual table to return all rows in the
+** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
+** [sqlite3_index_info] object.  This is the default expectation.  If the
+** virtual table outputs all rows in sorted order, then it is always safe for
+** the xBestIndex method to set the "orderByConsumed" flag, regardless of
+** the return value from sqlite3_vtab_distinct().
+** <li value="1"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
+** that the query planner does not need the rows to be returned in sorted order
+** as long as all rows with the same values in all columns identified by the
+** "aOrderBy" field are adjacent.)^  This mode is used when the query planner
+** is doing a GROUP BY.
+** <li value="2"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
+** that the query planner does not need the rows returned in any particular
+** order, as long as rows with the same values in all columns identified
+** by "aOrderBy" are adjacent.)^  ^(Furthermore, when two or more rows
+** contain the same values for all columns identified by "colUsed", all but
+** one such row may optionally be omitted from the result.)^
+** The virtual table is not required to omit rows that are duplicates
+** over the "colUsed" columns, but if the virtual table can do that without
+** too much extra effort, it could potentially help the query to run faster.
+** This mode is used for a DISTINCT query.
+** <li value="3"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 3, that means the
+** virtual table must return rows in the order defined by "aOrderBy" as
+** if the sqlite3_vtab_distinct() interface had returned 0.  However if
+** two or more rows in the result have the same values for all columns
+** identified by "colUsed", then all but one such row may optionally be
+** omitted.)^  Like when the return value is 2, the virtual table
+** is not required to omit rows that are duplicates over the "colUsed"
+** columns, but if the virtual table can do that without
+** too much extra effort, it could potentially help the query to run faster.
+** This mode is used for queries
+** that have both DISTINCT and ORDER BY clauses.
+** </ol>
+**
+** <p>The following table summarizes the conditions under which the
+** virtual table is allowed to set the "orderByConsumed" flag based on
+** the value returned by sqlite3_vtab_distinct().  This table is a
+** restatement of the previous four paragraphs:
+**
+** <table border=1 cellspacing=0 cellpadding=10 width="90%">
+** <tr>
+** <td valign="top">sqlite3_vtab_distinct() return value
+** <td valign="top">Rows are returned in aOrderBy order
+** <td valign="top">Rows with the same value in all aOrderBy columns are adjacent
+** <td valign="top">Duplicates over all colUsed columns may be omitted
+** <tr><td>0<td>yes<td>yes<td>no
+** <tr><td>1<td>no<td>yes<td>no
+** <tr><td>2<td>no<td>yes<td>yes
+** <tr><td>3<td>yes<td>yes<td>yes
+** </table>
+**
+** ^For the purposes of comparing virtual table output values to see if the
+** values are same value for sorting purposes, two NULL values are considered
+** to be the same.  In other words, the comparison operator is "IS"
+** (or "IS NOT DISTINCT FROM") and not "==".
+**
+** If a virtual table implementation is unable to meet the requirements
+** specified above, then it must not set the "orderByConsumed" flag in the
+** [sqlite3_index_info] object or an incorrect answer may result.
+**
+** ^A virtual table implementation is always free to return rows in any order
+** it wants, as long as the "orderByConsumed" flag is not set.  ^When the
+** the "orderByConsumed" flag is unset, the query planner will add extra
+** [bytecode] to ensure that the final results returned by the SQL query are
+** ordered correctly.  The use of the "orderByConsumed" flag and the
+** sqlite3_vtab_distinct() interface is merely an optimization.  ^Careful
+** use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
+** flag might help queries against a virtual table to run faster.  Being
+** overly aggressive and setting the "orderByConsumed" flag when it is not
+** valid to do so, on the other hand, might cause SQLite to return incorrect
+** results.
+*/
+SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info*);
+
+/*
+** CAPI3REF: Identify and handle IN constraints in xBestIndex
+**
+** This interface may only be used from within an
+** [xBestIndex|xBestIndex() method] of a [virtual table] implementation.
+** The result of invoking this interface from any other context is
+** undefined and probably harmful.
+**
+** ^(A constraint on a virtual table of the form
+** "[IN operator|column IN (...)]" is
+** communicated to the xBestIndex method as a
+** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^  If xBestIndex wants to use
+** this constraint, it must set the corresponding
+** aConstraintUsage[].argvIndex to a positive integer.  ^(Then, under
+** the usual mode of handling IN operators, SQLite generates [bytecode]
+** that invokes the [xFilter|xFilter() method] once for each value
+** on the right-hand side of the IN operator.)^  Thus the virtual table
+** only sees a single value from the right-hand side of the IN operator
+** at a time.
+**
+** In some cases, however, it would be advantageous for the virtual
+** table to see all values on the right-hand of the IN operator all at
+** once.  The sqlite3_vtab_in() interfaces facilitates this in two ways:
+**
+** <ol>
+** <li><p>
+**   ^A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
+**   if and only if the [sqlite3_index_info|P->aConstraint][N] constraint
+**   is an [IN operator] that can be processed all at once.  ^In other words,
+**   sqlite3_vtab_in() with -1 in the third argument is a mechanism
+**   by which the virtual table can ask SQLite if all-at-once processing
+**   of the IN operator is even possible.
+**
+** <li><p>
+**   ^A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
+**   to SQLite that the virtual table does or does not want to process
+**   the IN operator all-at-once, respectively.  ^Thus when the third
+**   parameter (F) is non-negative, this interface is the mechanism by
+**   which the virtual table tells SQLite how it wants to process the
+**   IN operator.
+** </ol>
+**
+** ^The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
+** within the same xBestIndex method call.  ^For any given P,N pair,
+** the return value from sqlite3_vtab_in(P,N,F) will always be the same
+** within the same xBestIndex call.  ^If the interface returns true
+** (non-zero), that means that the constraint is an IN operator
+** that can be processed all-at-once.  ^If the constraint is not an IN
+** operator or cannot be processed all-at-once, then the interface returns
+** false.
+**
+** ^(All-at-once processing of the IN operator is selected if both of the
+** following conditions are met:
+**
+** <ol>
+** <li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
+** integer.  This is how the virtual table tells SQLite that it wants to
+** use the N-th constraint.
+**
+** <li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
+** non-negative had F>=1.
+** </ol>)^
+**
+** ^If either or both of the conditions above are false, then SQLite uses
+** the traditional one-at-a-time processing strategy for the IN constraint.
+** ^If both conditions are true, then the argvIndex-th parameter to the
+** xFilter method will be an [sqlite3_value] that appears to be NULL,
+** but which can be passed to [sqlite3_vtab_in_first()] and
+** [sqlite3_vtab_in_next()] to find all values on the right-hand side
+** of the IN constraint.
+*/
+SQLITE_API int sqlite3_vtab_in(sqlite3_index_info*, int iCons, int bHandle);
+
+/*
+** CAPI3REF: Find all elements on the right-hand side of an IN constraint.
+**
+** These interfaces are only useful from within the
+** [xFilter|xFilter() method] of a [virtual table] implementation.
+** The result of invoking these interfaces from any other context
+** is undefined and probably harmful.
+**
+** The X parameter in a call to sqlite3_vtab_in_first(X,P) or
+** sqlite3_vtab_in_next(X,P) should be one of the parameters to the
+** xFilter method which invokes these routines, and specifically
+** a parameter that was previously selected for all-at-once IN constraint
+** processing use the [sqlite3_vtab_in()] interface in the
+** [xBestIndex|xBestIndex method].  ^(If the X parameter is not
+** an xFilter argument that was selected for all-at-once IN constraint
+** processing, then these routines return [SQLITE_ERROR].)^
+**
+** ^(Use these routines to access all values on the right-hand side
+** of the IN constraint using code like the following:
+**
+** <blockquote><pre>
+**    for(rc=sqlite3_vtab_in_first(pList, &pVal);
+**        rc==SQLITE_OK && pVal;
+**        rc=sqlite3_vtab_in_next(pList, &pVal)
+**    ){
+**      // do something with pVal
+**    }
+**    if( rc!=SQLITE_OK ){
+**      // an error has occurred
+**    }
+** </pre></blockquote>)^
+**
+** ^On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
+** routines return SQLITE_OK and set *P to point to the first or next value
+** on the RHS of the IN constraint.  ^If there are no more values on the
+** right hand side of the IN constraint, then *P is set to NULL and these
+** routines return [SQLITE_DONE].  ^The return value might be
+** some other value, such as SQLITE_NOMEM, in the event of a malfunction.
+**
+** The *ppOut values returned by these routines are only valid until the
+** next call to either of these routines or until the end of the xFilter
+** method from which these routines were called.  If the virtual table
+** implementation needs to retain the *ppOut values for longer, it must make
+** copies.  The *ppOut values are [protected sqlite3_value|protected].
+*/
+SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut);
+SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut);
+
+/*
+** CAPI3REF: Constraint values in xBestIndex()
+** METHOD: sqlite3_index_info
+**
+** This API may only be used from within the [xBestIndex|xBestIndex method]
+** of a [virtual table] implementation. The result of calling this interface
+** from outside of an xBestIndex method are undefined and probably harmful.
+**
+** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
+** the [xBestIndex] method of a [virtual table] implementation, with P being
+** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
+** J being a 0-based index into P->aConstraint[], then this routine
+** attempts to set *V to the value of the right-hand operand of
+** that constraint if the right-hand operand is known.  ^If the
+** right-hand operand is not known, then *V is set to a NULL pointer.
+** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
+** and only if *V is set to a value.  ^The sqlite3_vtab_rhs_value(P,J,V)
+** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
+** constraint is not available.  ^The sqlite3_vtab_rhs_value() interface
+** can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
+** something goes wrong.
+**
+** The sqlite3_vtab_rhs_value() interface is usually only successful if
+** the right-hand operand of a constraint is a literal value in the original
+** SQL statement.  If the right-hand operand is an expression or a reference
+** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
+** will probably return [SQLITE_NOTFOUND].
+**
+** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
+** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand.  For such
+** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
+**
+** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
+** and remains valid for the duration of the xBestIndex method call.
+** ^When xBestIndex returns, the sqlite3_value object returned by
+** sqlite3_vtab_rhs_value() is automatically deallocated.
+**
+** The "_rhs_" in the name of this routine is an abbreviation for
+** "Right-Hand Side".
+*/
+SQLITE_API int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);
+
+/*
+** CAPI3REF: Conflict resolution modes
+** KEYWORDS: {conflict resolution mode}
+**
+** These constants are returned by [sqlite3_vtab_on_conflict()] to
+** inform a [virtual table] implementation what the [ON CONFLICT] mode
+** is for the SQL statement being evaluated.
+**
+** Note that the [SQLITE_IGNORE] constant is also used as a potential
+** return value from the [sqlite3_set_authorizer()] callback and that
+** [SQLITE_ABORT] is also a [result code].
+*/
+#define SQLITE_ROLLBACK 1
+/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
+#define SQLITE_FAIL     3
+/* #define SQLITE_ABORT 4  // Also an error code */
+#define SQLITE_REPLACE  5
+
+/*
+** CAPI3REF: Prepared Statement Scan Status Opcodes
+** KEYWORDS: {scanstatus options}
+**
+** The following constants can be used for the T parameter to the
+** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
+** different metric for sqlite3_stmt_scanstatus() to return.
+**
+** When the value returned to V is a string, space to hold that string is
+** managed by the prepared statement S and will be automatically freed when
+** S is finalized.
+**
+** Not all values are available for all query elements. When a value is
+** not available, the output variable is set to -1 if the value is numeric,
+** or to NULL if it is a string (SQLITE_SCANSTAT_NAME).
+**
+** <dl>
+** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
+** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
+** set to the total number of times that the X-th loop has run.</dd>
+**
+** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
+** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
+** to the total number of rows examined by all iterations of the X-th loop.</dd>
+**
+** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
+** <dd>^The "double" variable pointed to by the V parameter will be set to the
+** query planner's estimate for the average number of rows output from each
+** iteration of the X-th loop.  If the query planner's estimates was accurate,
+** then this value will approximate the quotient NVISIT/NLOOP and the
+** product of this value for all prior loops with the same SELECTID will
+** be the NLOOP value for the current loop.
+**
+** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
+** <dd>^The "const char *" variable pointed to by the V parameter will be set
+** to a zero-terminated UTF-8 string containing the name of the index or table
+** used for the X-th loop.
+**
+** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
+** <dd>^The "const char *" variable pointed to by the V parameter will be set
+** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
+** description for the X-th loop.
+**
+** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECTID</dt>
+** <dd>^The "int" variable pointed to by the V parameter will be set to the
+** id for the X-th query plan element. The id value is unique within the
+** statement. The select-id is the same value as is output in the first
+** column of an [EXPLAIN QUERY PLAN] query.
+**
+** [[SQLITE_SCANSTAT_PARENTID]] <dt>SQLITE_SCANSTAT_PARENTID</dt>
+** <dd>The "int" variable pointed to by the V parameter will be set to the
+** the id of the parent of the current query element, if applicable, or
+** to zero if the query element has no parent. This is the same value as
+** returned in the second column of an [EXPLAIN QUERY PLAN] query.
+**
+** [[SQLITE_SCANSTAT_NCYCLE]] <dt>SQLITE_SCANSTAT_NCYCLE</dt>
+** <dd>The sqlite3_int64 output value is set to the number of cycles,
+** according to the processor time-stamp counter, that elapsed while the
+** query element was being processed. This value is not available for
+** all query elements - if it is unavailable the output variable is
+** set to -1.
+** </dl>
+*/
+#define SQLITE_SCANSTAT_NLOOP    0
+#define SQLITE_SCANSTAT_NVISIT   1
+#define SQLITE_SCANSTAT_EST      2
+#define SQLITE_SCANSTAT_NAME     3
+#define SQLITE_SCANSTAT_EXPLAIN  4
+#define SQLITE_SCANSTAT_SELECTID 5
+#define SQLITE_SCANSTAT_PARENTID 6
+#define SQLITE_SCANSTAT_NCYCLE   7
+
+/*
+** CAPI3REF: Prepared Statement Scan Status
+** METHOD: sqlite3_stmt
+**
+** These interfaces return information about the predicted and measured
+** performance for pStmt.  Advanced applications can use this
+** interface to compare the predicted and the measured performance and
+** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
+**
+** Since this interface is expected to be rarely used, it is only
+** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
+** compile-time option.
+**
+** The "iScanStatusOp" parameter determines which status information to return.
+** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
+** of this interface is undefined. ^The requested measurement is written into
+** a variable pointed to by the "pOut" parameter.
+**
+** The "flags" parameter must be passed a mask of flags. At present only
+** one flag is defined - SQLITE_SCANSTAT_COMPLEX. If SQLITE_SCANSTAT_COMPLEX
+** is specified, then status information is available for all elements
+** of a query plan that are reported by "EXPLAIN QUERY PLAN" output. If
+** SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
+** that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
+** the EXPLAIN QUERY PLAN output) are available. Invoking API
+** sqlite3_stmt_scanstatus() is equivalent to calling
+** sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.
+**
+** Parameter "idx" identifies the specific query element to retrieve statistics
+** for. Query elements are numbered starting from zero. A value of -1 may be
+** to query for statistics regarding the entire query. ^If idx is out of range
+** - less than -1 or greater than or equal to the total number of query
+** elements used to implement the statement - a non-zero value is returned and
+** the variable that pOut points to is unchanged.
+**
+** See also: [sqlite3_stmt_scanstatus_reset()]
+*/
+SQLITE_API int sqlite3_stmt_scanstatus(
+  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
+  int idx,                  /* Index of loop to report on */
+  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
+  void *pOut                /* Result written here */
+);
+SQLITE_API int sqlite3_stmt_scanstatus_v2(
+  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
+  int idx,                  /* Index of loop to report on */
+  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
+  int flags,                /* Mask of flags defined below */
+  void *pOut                /* Result written here */
+);
+
+/*
+** CAPI3REF: Prepared Statement Scan Status
+** KEYWORDS: {scan status flags}
+*/
+#define SQLITE_SCANSTAT_COMPLEX 0x0001
+
+/*
+** CAPI3REF: Zero Scan-Status Counters
+** METHOD: sqlite3_stmt
+**
+** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
+**
+** This API is only available if the library is built with pre-processor
+** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
+*/
+SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Flush caches to disk mid-transaction
+** METHOD: sqlite3
+**
+** ^If a write-transaction is open on [database connection] D when the
+** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
+** pages in the pager-cache that are not currently in use are written out
+** to disk. A dirty page may be in use if a database cursor created by an
+** active SQL statement is reading from it, or if it is page 1 of a database
+** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
+** interface flushes caches for all schemas - "main", "temp", and
+** any [attached] databases.
+**
+** ^If this function needs to obtain extra database locks before dirty pages
+** can be flushed to disk, it does so. ^If those locks cannot be obtained
+** immediately and there is a busy-handler callback configured, it is invoked
+** in the usual manner. ^If the required lock still cannot be obtained, then
+** the database is skipped and an attempt made to flush any dirty pages
+** belonging to the next (if any) database. ^If any databases are skipped
+** because locks cannot be obtained, but no other error occurs, this
+** function returns SQLITE_BUSY.
+**
+** ^If any other error occurs while flushing dirty pages to disk (for
+** example an IO error or out-of-memory condition), then processing is
+** abandoned and an SQLite [error code] is returned to the caller immediately.
+**
+** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
+**
+** ^This function does not set the database handle error code or message
+** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
+*/
+SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
+
+/*
+** CAPI3REF: The pre-update hook.
+** METHOD: sqlite3
+**
+** ^These interfaces are only available if SQLite is compiled using the
+** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
+**
+** ^The [sqlite3_preupdate_hook()] interface registers a callback function
+** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
+** on a database table.
+** ^At most one preupdate hook may be registered at a time on a single
+** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
+** the previous setting.
+** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
+** with a NULL pointer as the second parameter.
+** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
+** the first parameter to callbacks.
+**
+** ^The preupdate hook only fires for changes to real database tables; the
+** preupdate hook is not invoked for changes to [virtual tables] or to
+** system tables like sqlite_sequence or sqlite_stat1.
+**
+** ^The second parameter to the preupdate callback is a pointer to
+** the [database connection] that registered the preupdate hook.
+** ^The third parameter to the preupdate callback is one of the constants
+** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
+** kind of update operation that is about to occur.
+** ^(The fourth parameter to the preupdate callback is the name of the
+** database within the database connection that is being modified.  This
+** will be "main" for the main database or "temp" for TEMP tables or
+** the name given after the AS keyword in the [ATTACH] statement for attached
+** databases.)^
+** ^The fifth parameter to the preupdate callback is the name of the
+** table that is being modified.
+**
+** For an UPDATE or DELETE operation on a [rowid table], the sixth
+** parameter passed to the preupdate callback is the initial [rowid] of the
+** row being modified or deleted. For an INSERT operation on a rowid table,
+** or any operation on a WITHOUT ROWID table, the value of the sixth
+** parameter is undefined. For an INSERT or UPDATE on a rowid table the
+** seventh parameter is the final rowid value of the row being inserted
+** or updated. The value of the seventh parameter passed to the callback
+** function is not defined for operations on WITHOUT ROWID tables, or for
+** DELETE operations on rowid tables.
+**
+** ^The sqlite3_preupdate_hook(D,C,P) function returns the P argument from
+** the previous call on the same [database connection] D, or NULL for
+** the first call on D.
+**
+** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
+** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
+** provide additional information about a preupdate event. These routines
+** may only be called from within a preupdate callback.  Invoking any of
+** these routines from outside of a preupdate callback or with a
+** [database connection] pointer that is different from the one supplied
+** to the preupdate callback results in undefined and probably undesirable
+** behavior.
+**
+** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
+** in the row that is being inserted, updated, or deleted.
+**
+** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
+** a [protected sqlite3_value] that contains the value of the Nth column of
+** the table row before it is updated.  The N parameter must be between 0
+** and one less than the number of columns or the behavior will be
+** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
+** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
+** behavior is undefined.  The [sqlite3_value] that P points to
+** will be destroyed when the preupdate callback returns.
+**
+** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
+** a [protected sqlite3_value] that contains the value of the Nth column of
+** the table row after it is updated.  The N parameter must be between 0
+** and one less than the number of columns or the behavior will be
+** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
+** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
+** behavior is undefined.  The [sqlite3_value] that P points to
+** will be destroyed when the preupdate callback returns.
+**
+** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
+** callback was invoked as a result of a direct insert, update, or delete
+** operation; or 1 for inserts, updates, or deletes invoked by top-level
+** triggers; or 2 for changes resulting from triggers called by top-level
+** triggers; and so forth.
+**
+** When the [sqlite3_blob_write()] API is used to update a blob column,
+** the pre-update hook is invoked with SQLITE_DELETE. This is because the
+** in this case the new values are not available. In this case, when a
+** callback made with op==SQLITE_DELETE is actually a write using the
+** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
+** the index of the column being written. In other cases, where the
+** pre-update hook is being invoked for some other reason, including a
+** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
+**
+** See also:  [sqlite3_update_hook()]
+*/
+#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
+SQLITE_API void *sqlite3_preupdate_hook(
+  sqlite3 *db,
+  void(*xPreUpdate)(
+    void *pCtx,                   /* Copy of third arg to preupdate_hook() */
+    sqlite3 *db,                  /* Database handle */
+    int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
+    char const *zDb,              /* Database name */
+    char const *zName,            /* Table name */
+    sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
+    sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
+  ),
+  void*
+);
+SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
+SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
+SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
+SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
+SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *);
+#endif
+
+/*
+** CAPI3REF: Low-level system error code
+** METHOD: sqlite3
+**
+** ^Attempt to return the underlying operating system error code or error
+** number that caused the most recent I/O error or failure to open a file.
+** The return value is OS-dependent.  For example, on unix systems, after
+** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
+** called to get back the underlying "errno" that caused the problem, such
+** as ENOSPC, EAUTH, EISDIR, and so forth.
+*/
+SQLITE_API int sqlite3_system_errno(sqlite3*);
+
+/*
+** CAPI3REF: Database Snapshot
+** KEYWORDS: {snapshot} {sqlite3_snapshot}
+**
+** An instance of the snapshot object records the state of a [WAL mode]
+** database for some specific point in history.
+**
+** In [WAL mode], multiple [database connections] that are open on the
+** same database file can each be reading a different historical version
+** of the database file.  When a [database connection] begins a read
+** transaction, that connection sees an unchanging copy of the database
+** as it existed for the point in time when the transaction first started.
+** Subsequent changes to the database from other connections are not seen
+** by the reader until a new read transaction is started.
+**
+** The sqlite3_snapshot object records state information about an historical
+** version of the database file so that it is possible to later open a new read
+** transaction that sees that historical version of the database rather than
+** the most recent version.
+*/
+typedef struct sqlite3_snapshot {
+  unsigned char hidden[48];
+} sqlite3_snapshot;
+
+/*
+** CAPI3REF: Record A Database Snapshot
+** CONSTRUCTOR: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
+** new [sqlite3_snapshot] object that records the current state of
+** schema S in database connection D.  ^On success, the
+** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
+** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
+** If there is not already a read-transaction open on schema S when
+** this function is called, one is opened automatically.
+**
+** If a read-transaction is opened by this function, then it is guaranteed
+** that the returned snapshot object may not be invalidated by a database
+** writer or checkpointer until after the read-transaction is closed. This
+** is not guaranteed if a read-transaction is already open when this
+** function is called. In that case, any subsequent write or checkpoint
+** operation on the database may invalidate the returned snapshot handle,
+** even while the read-transaction remains open.
+**
+** The following must be true for this function to succeed. If any of
+** the following statements are false when sqlite3_snapshot_get() is
+** called, SQLITE_ERROR is returned. The final value of *P is undefined
+** in this case.
+**
+** <ul>
+**   <li> The database handle must not be in [autocommit mode].
+**
+**   <li> Schema S of [database connection] D must be a [WAL mode] database.
+**
+**   <li> There must not be a write transaction open on schema S of database
+**        connection D.
+**
+**   <li> One or more transactions must have been written to the current wal
+**        file since it was created on disk (by any connection). This means
+**        that a snapshot cannot be taken on a wal mode database with no wal
+**        file immediately after it is first opened. At least one transaction
+**        must be written to it first.
+** </ul>
+**
+** This function may also return SQLITE_NOMEM.  If it is called with the
+** database handle in autocommit mode but fails for some other reason,
+** whether or not a read transaction is opened on schema S is undefined.
+**
+** The [sqlite3_snapshot] object returned from a successful call to
+** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
+** to avoid a memory leak.
+**
+** The [sqlite3_snapshot_get()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
+  sqlite3 *db,
+  const char *zSchema,
+  sqlite3_snapshot **ppSnapshot
+);
+
+/*
+** CAPI3REF: Start a read transaction on an historical snapshot
+** METHOD: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
+** transaction or upgrades an existing one for schema S of
+** [database connection] D such that the read transaction refers to
+** historical [snapshot] P, rather than the most recent change to the
+** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
+** on success or an appropriate [error code] if it fails.
+**
+** ^In order to succeed, the database connection must not be in
+** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
+** is already a read transaction open on schema S, then the database handle
+** must have no active statements (SELECT statements that have been passed
+** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
+** SQLITE_ERROR is returned if either of these conditions is violated, or
+** if schema S does not exist, or if the snapshot object is invalid.
+**
+** ^A call to sqlite3_snapshot_open() will fail to open if the specified
+** snapshot has been overwritten by a [checkpoint]. In this case
+** SQLITE_ERROR_SNAPSHOT is returned.
+**
+** If there is already a read transaction open when this function is
+** invoked, then the same read transaction remains open (on the same
+** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
+** is returned. If another error code - for example SQLITE_PROTOCOL or an
+** SQLITE_IOERR error code - is returned, then the final state of the
+** read transaction is undefined. If SQLITE_OK is returned, then the
+** read transaction is now open on database snapshot P.
+**
+** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
+** database connection D does not know that the database file for
+** schema S is in [WAL mode].  A database connection might not know
+** that the database file is in [WAL mode] if there has been no prior
+** I/O on that database connection, or if the database entered [WAL mode]
+** after the most recent I/O on the database connection.)^
+** (Hint: Run "[PRAGMA application_id]" against a newly opened
+** database connection in order to make it ready to use snapshots.)
+**
+** The [sqlite3_snapshot_open()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
+  sqlite3 *db,
+  const char *zSchema,
+  sqlite3_snapshot *pSnapshot
+);
+
+/*
+** CAPI3REF: Destroy a snapshot
+** DESTRUCTOR: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
+** The application must eventually free every [sqlite3_snapshot] object
+** using this routine to avoid a memory leak.
+**
+** The [sqlite3_snapshot_free()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
+
+/*
+** CAPI3REF: Compare the ages of two snapshot handles.
+** METHOD: sqlite3_snapshot
+**
+** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
+** of two valid snapshot handles.
+**
+** If the two snapshot handles are not associated with the same database
+** file, the result of the comparison is undefined.
+**
+** Additionally, the result of the comparison is only valid if both of the
+** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
+** last time the wal file was deleted. The wal file is deleted when the
+** database is changed back to rollback mode or when the number of database
+** clients drops to zero. If either snapshot handle was obtained before the
+** wal file was last deleted, the value returned by this function
+** is undefined.
+**
+** Otherwise, this API returns a negative value if P1 refers to an older
+** snapshot than P2, zero if the two handles refer to the same database
+** snapshot, and a positive value if P1 is a newer snapshot than P2.
+**
+** This interface is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SNAPSHOT] option.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
+  sqlite3_snapshot *p1,
+  sqlite3_snapshot *p2
+);
+
+/*
+** CAPI3REF: Recover snapshots from a wal file
+** METHOD: sqlite3_snapshot
+**
+** If a [WAL file] remains on disk after all database connections close
+** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
+** or because the last process to have the database opened exited without
+** calling [sqlite3_close()]) and a new connection is subsequently opened
+** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
+** will only be able to open the last transaction added to the WAL file
+** even though the WAL file contains other valid transactions.
+**
+** This function attempts to scan the WAL file associated with database zDb
+** of database handle db and make all valid snapshots available to
+** sqlite3_snapshot_open(). It is an error if there is already a read
+** transaction open on the database, or if the database is not a WAL mode
+** database.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+**
+** This interface is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SNAPSHOT] option.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Serialize a database
+**
+** The sqlite3_serialize(D,S,P,F) interface returns a pointer to
+** memory that is a serialization of the S database on
+** [database connection] D.  If S is a NULL pointer, the main database is used.
+** If P is not a NULL pointer, then the size of the database in bytes
+** is written into *P.
+**
+** For an ordinary on-disk database file, the serialization is just a
+** copy of the disk file.  For an in-memory database or a "TEMP" database,
+** the serialization is the same sequence of bytes which would be written
+** to disk if that database where backed up to disk.
+**
+** The usual case is that sqlite3_serialize() copies the serialization of
+** the database into memory obtained from [sqlite3_malloc64()] and returns
+** a pointer to that memory.  The caller is responsible for freeing the
+** returned value to avoid a memory leak.  However, if the F argument
+** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
+** are made, and the sqlite3_serialize() function will return a pointer
+** to the contiguous memory representation of the database that SQLite
+** is currently using for that database, or NULL if the no such contiguous
+** memory representation of the database exists.  A contiguous memory
+** representation of the database will usually only exist if there has
+** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
+** values of D and S.
+** The size of the database is written into *P even if the
+** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
+** of the database exists.
+**
+** After the call, if the SQLITE_SERIALIZE_NOCOPY bit had been set,
+** the returned buffer content will remain accessible and unchanged
+** until either the next write operation on the connection or when
+** the connection is closed, and applications must not modify the
+** buffer. If the bit had been clear, the returned buffer will not
+** be accessed by SQLite after the call.
+**
+** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
+** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
+** allocation error occurs.
+**
+** This interface is omitted if SQLite is compiled with the
+** [SQLITE_OMIT_DESERIALIZE] option.
+*/
+SQLITE_API unsigned char *sqlite3_serialize(
+  sqlite3 *db,           /* The database connection */
+  const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
+  sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
+  unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3_serialize
+**
+** Zero or more of the following constants can be OR-ed together for
+** the F argument to [sqlite3_serialize(D,S,P,F)].
+**
+** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
+** a pointer to contiguous in-memory database that it is currently using,
+** without making a copy of the database.  If SQLite is not currently using
+** a contiguous in-memory database, then this option causes
+** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
+** using a contiguous in-memory database if it has been initialized by a
+** prior call to [sqlite3_deserialize()].
+*/
+#define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
+
+/*
+** CAPI3REF: Deserialize a database
+**
+** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
+** [database connection] D to disconnect from database S and then
+** reopen S as an in-memory database based on the serialization contained
+** in P.  The serialized database P is N bytes in size.  M is the size of
+** the buffer P, which might be larger than N.  If M is larger than N, and
+** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
+** permitted to add content to the in-memory database as long as the total
+** size does not exceed M bytes.
+**
+** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
+** invoke sqlite3_free() on the serialization buffer when the database
+** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
+** SQLite will try to increase the buffer size using sqlite3_realloc64()
+** if writes on the database cause it to grow larger than M bytes.
+**
+** Applications must not modify the buffer P or invalidate it before
+** the database connection D is closed.
+**
+** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
+** database is currently in a read transaction or is involved in a backup
+** operation.
+**
+** It is not possible to deserialized into the TEMP database.  If the
+** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
+** function returns SQLITE_ERROR.
+**
+** The deserialized database should not be in [WAL mode].  If the database
+** is in WAL mode, then any attempt to use the database file will result
+** in an [SQLITE_CANTOPEN] error.  The application can set the
+** [file format version numbers] (bytes 18 and 19) of the input database P
+** to 0x01 prior to invoking sqlite3_deserialize(D,S,P,N,M,F) to force the
+** database file into rollback mode and work around this limitation.
+**
+** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
+** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
+** [sqlite3_free()] is invoked on argument P prior to returning.
+**
+** This interface is omitted if SQLite is compiled with the
+** [SQLITE_OMIT_DESERIALIZE] option.
+*/
+SQLITE_API int sqlite3_deserialize(
+  sqlite3 *db,            /* The database connection */
+  const char *zSchema,    /* Which DB to reopen with the deserialization */
+  unsigned char *pData,   /* The serialized database content */
+  sqlite3_int64 szDb,     /* Number bytes in the deserialization */
+  sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
+  unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3_deserialize()
+**
+** The following are allowed values for 6th argument (the F argument) to
+** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
+**
+** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
+** in the P argument is held in memory obtained from [sqlite3_malloc64()]
+** and that SQLite should take ownership of this memory and automatically
+** free it when it has finished using it.  Without this flag, the caller
+** is responsible for freeing any dynamically allocated memory.
+**
+** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
+** grow the size of the database using calls to [sqlite3_realloc64()].  This
+** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
+** Without this flag, the deserialized database cannot increase in size beyond
+** the number of bytes specified by the M parameter.
+**
+** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
+** should be treated as read-only.
+*/
+#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
+#define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
+#define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
+
+/*
+** Undo the hack that converts floating point types to integer for
+** builds on processors without floating point support.
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# undef double
+#endif
+
+#if defined(__wasi__)
+# undef SQLITE_WASI
+# define SQLITE_WASI 1
+# ifndef SQLITE_OMIT_LOAD_EXTENSION
+#  define SQLITE_OMIT_LOAD_EXTENSION
+# endif
+# ifndef SQLITE_THREADSAFE
+#  define SQLITE_THREADSAFE 0
+# endif
+#endif
+
+#if 0
+}  /* End of the 'extern "C"' block */
+#endif
+/* #endif for SQLITE3_H will be added by mksqlite3.tcl */
+
+/******** Begin file sqlite3rtree.h *********/
+/*
+** 2010 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+
+#ifndef _SQLITE3RTREE_H_
+#define _SQLITE3RTREE_H_
+
+
+#if 0
+extern "C" {
+#endif
+
+typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
+typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
+
+/* The double-precision datatype used by RTree depends on the
+** SQLITE_RTREE_INT_ONLY compile-time option.
+*/
+#ifdef SQLITE_RTREE_INT_ONLY
+  typedef sqlite3_int64 sqlite3_rtree_dbl;
+#else
+  typedef double sqlite3_rtree_dbl;
+#endif
+
+/*
+** Register a geometry callback named zGeom that can be used as part of an
+** R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_geometry_callback(
+  sqlite3 *db,
+  const char *zGeom,
+  int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
+  void *pContext
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the first
+** argument to callbacks registered using rtree_geometry_callback().
+*/
+struct sqlite3_rtree_geometry {
+  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
+  int nParam;                     /* Size of array aParam[] */
+  sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
+  void *pUser;                    /* Callback implementation user data */
+  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
+};
+
+/*
+** Register a 2nd-generation geometry callback named zScore that can be
+** used as part of an R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_query_callback(
+  sqlite3 *db,
+  const char *zQueryFunc,
+  int (*xQueryFunc)(sqlite3_rtree_query_info*),
+  void *pContext,
+  void (*xDestructor)(void*)
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the
+** argument to scored geometry callback registered using
+** sqlite3_rtree_query_callback().
+**
+** Note that the first 5 fields of this structure are identical to
+** sqlite3_rtree_geometry.  This structure is a subclass of
+** sqlite3_rtree_geometry.
+*/
+struct sqlite3_rtree_query_info {
+  void *pContext;                   /* pContext from when function registered */
+  int nParam;                       /* Number of function parameters */
+  sqlite3_rtree_dbl *aParam;        /* value of function parameters */
+  void *pUser;                      /* callback can use this, if desired */
+  void (*xDelUser)(void*);          /* function to free pUser */
+  sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
+  unsigned int *anQueue;            /* Number of pending entries in the queue */
+  int nCoord;                       /* Number of coordinates */
+  int iLevel;                       /* Level of current node or entry */
+  int mxLevel;                      /* The largest iLevel value in the tree */
+  sqlite3_int64 iRowid;             /* Rowid for current entry */
+  sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
+  int eParentWithin;                /* Visibility of parent node */
+  int eWithin;                      /* OUT: Visibility */
+  sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
+  /* The following fields are only available in 3.8.11 and later */
+  sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
+};
+
+/*
+** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
+*/
+#define NOT_WITHIN       0   /* Object completely outside of query region */
+#define PARTLY_WITHIN    1   /* Object partially overlaps query region */
+#define FULLY_WITHIN     2   /* Object fully contained within query region */
+
+
+#if 0
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif  /* ifndef _SQLITE3RTREE_H_ */
+
+/******** End of sqlite3rtree.h *********/
+/******** Begin file sqlite3session.h *********/
+
+#if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
+#define __SQLITESESSION_H_ 1
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#if 0
+extern "C" {
+#endif
+
+
+/*
+** CAPI3REF: Session Object Handle
+**
+** An instance of this object is a [session] that can be used to
+** record changes to a database.
+*/
+typedef struct sqlite3_session sqlite3_session;
+
+/*
+** CAPI3REF: Changeset Iterator Handle
+**
+** An instance of this object acts as a cursor for iterating
+** over the elements of a [changeset] or [patchset].
+*/
+typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
+
+/*
+** CAPI3REF: Create A New Session Object
+** CONSTRUCTOR: sqlite3_session
+**
+** Create a new session object attached to database handle db. If successful,
+** a pointer to the new object is written to *ppSession and SQLITE_OK is
+** returned. If an error occurs, *ppSession is set to NULL and an SQLite
+** error code (e.g. SQLITE_NOMEM) is returned.
+**
+** It is possible to create multiple session objects attached to a single
+** database handle.
+**
+** Session objects created using this function should be deleted using the
+** [sqlite3session_delete()] function before the database handle that they
+** are attached to is itself closed. If the database handle is closed before
+** the session object is deleted, then the results of calling any session
+** module function, including [sqlite3session_delete()] on the session object
+** are undefined.
+**
+** Because the session module uses the [sqlite3_preupdate_hook()] API, it
+** is not possible for an application to register a pre-update hook on a
+** database handle that has one or more session objects attached. Nor is
+** it possible to create a session object attached to a database handle for
+** which a pre-update hook is already defined. The results of attempting
+** either of these things are undefined.
+**
+** The session object will be used to create changesets for tables in
+** database zDb, where zDb is either "main", or "temp", or the name of an
+** attached database. It is not an error if database zDb is not attached
+** to the database when the session object is created.
+*/
+SQLITE_API int sqlite3session_create(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of db (e.g. "main") */
+  sqlite3_session **ppSession     /* OUT: New session object */
+);
+
+/*
+** CAPI3REF: Delete A Session Object
+** DESTRUCTOR: sqlite3_session
+**
+** Delete a session object previously allocated using
+** [sqlite3session_create()]. Once a session object has been deleted, the
+** results of attempting to use pSession with any other session module
+** function are undefined.
+**
+** Session objects must be deleted before the database handle to which they
+** are attached is closed. Refer to the documentation for
+** [sqlite3session_create()] for details.
+*/
+SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Configure a Session Object
+** METHOD: sqlite3_session
+**
+** This method is used to configure a session object after it has been
+** created. At present the only valid values for the second parameter are
+** [SQLITE_SESSION_OBJCONFIG_SIZE] and [SQLITE_SESSION_OBJCONFIG_ROWID].
+**
+*/
+SQLITE_API int sqlite3session_object_config(sqlite3_session*, int op, void *pArg);
+
+/*
+** CAPI3REF: Options for sqlite3session_object_config
+**
+** The following values may passed as the the 2nd parameter to
+** sqlite3session_object_config().
+**
+** <dt>SQLITE_SESSION_OBJCONFIG_SIZE <dd>
+**   This option is used to set, clear or query the flag that enables
+**   the [sqlite3session_changeset_size()] API. Because it imposes some
+**   computational overhead, this API is disabled by default. Argument
+**   pArg must point to a value of type (int). If the value is initially
+**   0, then the sqlite3session_changeset_size() API is disabled. If it
+**   is greater than 0, then the same API is enabled. Or, if the initial
+**   value is less than zero, no change is made. In all cases the (int)
+**   variable is set to 1 if the sqlite3session_changeset_size() API is
+**   enabled following the current call, or 0 otherwise.
+**
+**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
+**   the first table has been attached to the session object.
+**
+** <dt>SQLITE_SESSION_OBJCONFIG_ROWID <dd>
+**   This option is used to set, clear or query the flag that enables
+**   collection of data for tables with no explicit PRIMARY KEY.
+**
+**   Normally, tables with no explicit PRIMARY KEY are simply ignored
+**   by the sessions module. However, if this flag is set, it behaves
+**   as if such tables have a column "_rowid_ INTEGER PRIMARY KEY" inserted
+**   as their leftmost columns.
+**
+**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
+**   the first table has been attached to the session object.
+*/
+#define SQLITE_SESSION_OBJCONFIG_SIZE  1
+#define SQLITE_SESSION_OBJCONFIG_ROWID 2
+
+/*
+** CAPI3REF: Enable Or Disable A Session Object
+** METHOD: sqlite3_session
+**
+** Enable or disable the recording of changes by a session object. When
+** enabled, a session object records changes made to the database. When
+** disabled - it does not. A newly created session object is enabled.
+** Refer to the documentation for [sqlite3session_changeset()] for further
+** details regarding how enabling and disabling a session object affects
+** the eventual changesets.
+**
+** Passing zero to this function disables the session. Passing a value
+** greater than zero enables it. Passing a value less than zero is a
+** no-op, and may be used to query the current state of the session.
+**
+** The return value indicates the final state of the session object: 0 if
+** the session is disabled, or 1 if it is enabled.
+*/
+SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
+
+/*
+** CAPI3REF: Set Or Clear the Indirect Change Flag
+** METHOD: sqlite3_session
+**
+** Each change recorded by a session object is marked as either direct or
+** indirect. A change is marked as indirect if either:
+**
+** <ul>
+**   <li> The session object "indirect" flag is set when the change is
+**        made, or
+**   <li> The change is made by an SQL trigger or foreign key action
+**        instead of directly as a result of a users SQL statement.
+** </ul>
+**
+** If a single row is affected by more than one operation within a session,
+** then the change is considered indirect if all operations meet the criteria
+** for an indirect change above, or direct otherwise.
+**
+** This function is used to set, clear or query the session object indirect
+** flag.  If the second argument passed to this function is zero, then the
+** indirect flag is cleared. If it is greater than zero, the indirect flag
+** is set. Passing a value less than zero does not modify the current value
+** of the indirect flag, and may be used to query the current state of the
+** indirect flag for the specified session object.
+**
+** The return value indicates the final state of the indirect flag: 0 if
+** it is clear, or 1 if it is set.
+*/
+SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
+
+/*
+** CAPI3REF: Attach A Table To A Session Object
+** METHOD: sqlite3_session
+**
+** If argument zTab is not NULL, then it is the name of a table to attach
+** to the session object passed as the first argument. All subsequent changes
+** made to the table while the session object is enabled will be recorded. See
+** documentation for [sqlite3session_changeset()] for further details.
+**
+** Or, if argument zTab is NULL, then changes are recorded for all tables
+** in the database. If additional tables are added to the database (by
+** executing "CREATE TABLE" statements) after this call is made, changes for
+** the new tables are also recorded.
+**
+** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
+** defined as part of their CREATE TABLE statement. It does not matter if the
+** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
+** KEY may consist of a single column, or may be a composite key.
+**
+** It is not an error if the named table does not exist in the database. Nor
+** is it an error if the named table does not have a PRIMARY KEY. However,
+** no changes will be recorded in either of these scenarios.
+**
+** Changes are not recorded for individual rows that have NULL values stored
+** in one or more of their PRIMARY KEY columns.
+**
+** SQLITE_OK is returned if the call completes without error. Or, if an error
+** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
+**
+** <h3>Special sqlite_stat1 Handling</h3>
+**
+** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
+** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
+**  <pre>
+**        CREATE TABLE sqlite_stat1(tbl,idx,stat)
+**  </pre>
+**
+** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
+** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
+** are recorded for rows for which (idx IS NULL) is true. However, for such
+** rows a zero-length blob (SQL value X'') is stored in the changeset or
+** patchset instead of a NULL value. This allows such changesets to be
+** manipulated by legacy implementations of sqlite3changeset_invert(),
+** concat() and similar.
+**
+** The sqlite3changeset_apply() function automatically converts the
+** zero-length blob back to a NULL value when updating the sqlite_stat1
+** table. However, if the application calls sqlite3changeset_new(),
+** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
+** iterator directly (including on a changeset iterator passed to a
+** conflict-handler callback) then the X'' value is returned. The application
+** must translate X'' to NULL itself if required.
+**
+** Legacy (older than 3.22.0) versions of the sessions module cannot capture
+** changes made to the sqlite_stat1 table. Legacy versions of the
+** sqlite3changeset_apply() function silently ignore any modifications to the
+** sqlite_stat1 table that are part of a changeset or patchset.
+*/
+SQLITE_API int sqlite3session_attach(
+  sqlite3_session *pSession,      /* Session object */
+  const char *zTab                /* Table name */
+);
+
+/*
+** CAPI3REF: Set a table filter on a Session Object.
+** METHOD: sqlite3_session
+**
+** The second argument (xFilter) is the "filter callback". For changes to rows
+** in tables that are not attached to the Session object, the filter is called
+** to determine whether changes to the table's rows should be tracked or not.
+** If xFilter returns 0, changes are not tracked. Note that once a table is
+** attached, xFilter will not be called again.
+*/
+SQLITE_API void sqlite3session_table_filter(
+  sqlite3_session *pSession,      /* Session object */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of third arg to _filter_table() */
+    const char *zTab              /* Table name */
+  ),
+  void *pCtx                      /* First argument passed to xFilter */
+);
+
+/*
+** CAPI3REF: Generate A Changeset From A Session Object
+** METHOD: sqlite3_session
+**
+** Obtain a changeset containing changes to the tables attached to the
+** session object passed as the first argument. If successful,
+** set *ppChangeset to point to a buffer containing the changeset
+** and *pnChangeset to the size of the changeset in bytes before returning
+** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
+** zero and return an SQLite error code.
+**
+** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
+** each representing a change to a single row of an attached table. An INSERT
+** change contains the values of each field of a new database row. A DELETE
+** contains the original values of each field of a deleted database row. An
+** UPDATE change contains the original values of each field of an updated
+** database row along with the updated values for each updated non-primary-key
+** column. It is not possible for an UPDATE change to represent a change that
+** modifies the values of primary key columns. If such a change is made, it
+** is represented in a changeset as a DELETE followed by an INSERT.
+**
+** Changes are not recorded for rows that have NULL values stored in one or
+** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
+** no corresponding change is present in the changesets returned by this
+** function. If an existing row with one or more NULL values stored in
+** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
+** only an INSERT is appears in the changeset. Similarly, if an existing row
+** with non-NULL PRIMARY KEY values is updated so that one or more of its
+** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
+** DELETE change only.
+**
+** The contents of a changeset may be traversed using an iterator created
+** using the [sqlite3changeset_start()] API. A changeset may be applied to
+** a database with a compatible schema using the [sqlite3changeset_apply()]
+** API.
+**
+** Within a changeset generated by this function, all changes related to a
+** single table are grouped together. In other words, when iterating through
+** a changeset or when applying a changeset to a database, all changes related
+** to a single table are processed before moving on to the next table. Tables
+** are sorted in the same order in which they were attached (or auto-attached)
+** to the sqlite3_session object. The order in which the changes related to
+** a single table are stored is undefined.
+**
+** Following a successful call to this function, it is the responsibility of
+** the caller to eventually free the buffer that *ppChangeset points to using
+** [sqlite3_free()].
+**
+** <h3>Changeset Generation</h3>
+**
+** Once a table has been attached to a session object, the session object
+** records the primary key values of all new rows inserted into the table.
+** It also records the original primary key and other column values of any
+** deleted or updated rows. For each unique primary key value, data is only
+** recorded once - the first time a row with said primary key is inserted,
+** updated or deleted in the lifetime of the session.
+**
+** There is one exception to the previous paragraph: when a row is inserted,
+** updated or deleted, if one or more of its primary key columns contain a
+** NULL value, no record of the change is made.
+**
+** The session object therefore accumulates two types of records - those
+** that consist of primary key values only (created when the user inserts
+** a new record) and those that consist of the primary key values and the
+** original values of other table columns (created when the users deletes
+** or updates a record).
+**
+** When this function is called, the requested changeset is created using
+** both the accumulated records and the current contents of the database
+** file. Specifically:
+**
+** <ul>
+**   <li> For each record generated by an insert, the database is queried
+**        for a row with a matching primary key. If one is found, an INSERT
+**        change is added to the changeset. If no such row is found, no change
+**        is added to the changeset.
+**
+**   <li> For each record generated by an update or delete, the database is
+**        queried for a row with a matching primary key. If such a row is
+**        found and one or more of the non-primary key fields have been
+**        modified from their original values, an UPDATE change is added to
+**        the changeset. Or, if no such row is found in the table, a DELETE
+**        change is added to the changeset. If there is a row with a matching
+**        primary key in the database, but all fields contain their original
+**        values, no change is added to the changeset.
+** </ul>
+**
+** This means, amongst other things, that if a row is inserted and then later
+** deleted while a session object is active, neither the insert nor the delete
+** will be present in the changeset. Or if a row is deleted and then later a
+** row with the same primary key values inserted while a session object is
+** active, the resulting changeset will contain an UPDATE change instead of
+** a DELETE and an INSERT.
+**
+** When a session object is disabled (see the [sqlite3session_enable()] API),
+** it does not accumulate records when rows are inserted, updated or deleted.
+** This may appear to have some counter-intuitive effects if a single row
+** is written to more than once during a session. For example, if a row
+** is inserted while a session object is enabled, then later deleted while
+** the same session object is disabled, no INSERT record will appear in the
+** changeset, even though the delete took place while the session was disabled.
+** Or, if one field of a row is updated while a session is disabled, and
+** another field of the same row is updated while the session is enabled, the
+** resulting changeset will contain an UPDATE change that updates both fields.
+*/
+SQLITE_API int sqlite3session_changeset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
+  void **ppChangeset              /* OUT: Buffer containing changeset */
+);
+
+/*
+** CAPI3REF: Return An Upper-limit For The Size Of The Changeset
+** METHOD: sqlite3_session
+**
+** By default, this function always returns 0. For it to return
+** a useful result, the sqlite3_session object must have been configured
+** to enable this API using sqlite3session_object_config() with the
+** SQLITE_SESSION_OBJCONFIG_SIZE verb.
+**
+** When enabled, this function returns an upper limit, in bytes, for the size
+** of the changeset that might be produced if sqlite3session_changeset() were
+** called. The final changeset size might be equal to or smaller than the
+** size in bytes returned by this function.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Load The Difference Between Tables Into A Session
+** METHOD: sqlite3_session
+**
+** If it is not already attached to the session object passed as the first
+** argument, this function attaches table zTbl in the same manner as the
+** [sqlite3session_attach()] function. If zTbl does not exist, or if it
+** does not have a primary key, this function is a no-op (but does not return
+** an error).
+**
+** Argument zFromDb must be the name of a database ("main", "temp" etc.)
+** attached to the same database handle as the session object that contains
+** a table compatible with the table attached to the session by this function.
+** A table is considered compatible if it:
+**
+** <ul>
+**   <li> Has the same name,
+**   <li> Has the same set of columns declared in the same order, and
+**   <li> Has the same PRIMARY KEY definition.
+** </ul>
+**
+** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
+** are compatible but do not have any PRIMARY KEY columns, it is not an error
+** but no changes are added to the session object. As with other session
+** APIs, tables without PRIMARY KEYs are simply ignored.
+**
+** This function adds a set of changes to the session object that could be
+** used to update the table in database zFrom (call this the "from-table")
+** so that its content is the same as the table attached to the session
+** object (call this the "to-table"). Specifically:
+**
+** <ul>
+**   <li> For each row (primary key) that exists in the to-table but not in
+**     the from-table, an INSERT record is added to the session object.
+**
+**   <li> For each row (primary key) that exists in the to-table but not in
+**     the from-table, a DELETE record is added to the session object.
+**
+**   <li> For each row (primary key) that exists in both tables, but features
+**     different non-PK values in each, an UPDATE record is added to the
+**     session.
+** </ul>
+**
+** To clarify, if this function is called and then a changeset constructed
+** using [sqlite3session_changeset()], then after applying that changeset to
+** database zFrom the contents of the two compatible tables would be
+** identical.
+**
+** It an error if database zFrom does not exist or does not contain the
+** required compatible table.
+**
+** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
+** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
+** may be set to point to a buffer containing an English language error
+** message. It is the responsibility of the caller to free this buffer using
+** sqlite3_free().
+*/
+SQLITE_API int sqlite3session_diff(
+  sqlite3_session *pSession,
+  const char *zFromDb,
+  const char *zTbl,
+  char **pzErrMsg
+);
+
+
+/*
+** CAPI3REF: Generate A Patchset From A Session Object
+** METHOD: sqlite3_session
+**
+** The differences between a patchset and a changeset are that:
+**
+** <ul>
+**   <li> DELETE records consist of the primary key fields only. The
+**        original values of other fields are omitted.
+**   <li> The original values of any modified fields are omitted from
+**        UPDATE records.
+** </ul>
+**
+** A patchset blob may be used with up to date versions of all
+** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
+** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
+** attempting to use a patchset blob with old versions of the
+** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
+**
+** Because the non-primary key "old.*" fields are omitted, no
+** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
+** is passed to the sqlite3changeset_apply() API. Other conflict types work
+** in the same way as for changesets.
+**
+** Changes within a patchset are ordered in the same way as for changesets
+** generated by the sqlite3session_changeset() function (i.e. all changes for
+** a single table are grouped together, tables appear in the order in which
+** they were attached to the session object).
+*/
+SQLITE_API int sqlite3session_patchset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
+  void **ppPatchset               /* OUT: Buffer containing patchset */
+);
+
+/*
+** CAPI3REF: Test if a changeset has recorded any changes.
+**
+** Return non-zero if no changes to attached tables have been recorded by
+** the session object passed as the first argument. Otherwise, if one or
+** more changes have been recorded, return zero.
+**
+** Even if this function returns zero, it is possible that calling
+** [sqlite3session_changeset()] on the session handle may still return a
+** changeset that contains no changes. This can happen when a row in
+** an attached table is modified and then later on the original values
+** are restored. However, if this function returns non-zero, then it is
+** guaranteed that a call to sqlite3session_changeset() will return a
+** changeset containing zero changes.
+*/
+SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Query for the amount of heap memory used by a session object.
+**
+** This API returns the total amount of heap memory in bytes currently
+** used by the session object passed as the only argument.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Create An Iterator To Traverse A Changeset
+** CONSTRUCTOR: sqlite3_changeset_iter
+**
+** Create an iterator used to iterate through the contents of a changeset.
+** If successful, *pp is set to point to the iterator handle and SQLITE_OK
+** is returned. Otherwise, if an error occurs, *pp is set to zero and an
+** SQLite error code is returned.
+**
+** The following functions can be used to advance and query a changeset
+** iterator created by this function:
+**
+** <ul>
+**   <li> [sqlite3changeset_next()]
+**   <li> [sqlite3changeset_op()]
+**   <li> [sqlite3changeset_new()]
+**   <li> [sqlite3changeset_old()]
+** </ul>
+**
+** It is the responsibility of the caller to eventually destroy the iterator
+** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
+** changeset (pChangeset) must remain valid until after the iterator is
+** destroyed.
+**
+** Assuming the changeset blob was created by one of the
+** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
+** [sqlite3changeset_invert()] functions, all changes within the changeset
+** that apply to a single table are grouped together. This means that when
+** an application iterates through a changeset using an iterator created by
+** this function, all changes that relate to a single table are visited
+** consecutively. There is no chance that the iterator will visit a change
+** the applies to table X, then one for table Y, and then later on visit
+** another change for table X.
+**
+** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
+** may be modified by passing a combination of
+** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
+**
+** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
+** and therefore subject to change.
+*/
+SQLITE_API int sqlite3changeset_start(
+  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
+  int nChangeset,                 /* Size of changeset blob in bytes */
+  void *pChangeset                /* Pointer to blob containing changeset */
+);
+SQLITE_API int sqlite3changeset_start_v2(
+  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
+  int nChangeset,                 /* Size of changeset blob in bytes */
+  void *pChangeset,               /* Pointer to blob containing changeset */
+  int flags                       /* SESSION_CHANGESETSTART_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3changeset_start_v2
+**
+** The following flags may passed via the 4th parameter to
+** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
+**
+** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
+**   Invert the changeset while iterating through it. This is equivalent to
+**   inverting a changeset using sqlite3changeset_invert() before applying it.
+**   It is an error to specify this flag with a patchset.
+*/
+#define SQLITE_CHANGESETSTART_INVERT        0x0002
+
+
+/*
+** CAPI3REF: Advance A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function may only be used with iterators created by the function
+** [sqlite3changeset_start()]. If it is called on an iterator passed to
+** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
+** is returned and the call has no effect.
+**
+** Immediately after an iterator is created by sqlite3changeset_start(), it
+** does not point to any change in the changeset. Assuming the changeset
+** is not empty, the first call to this function advances the iterator to
+** point to the first change in the changeset. Each subsequent call advances
+** the iterator to point to the next change in the changeset (if any). If
+** no error occurs and the iterator points to a valid change after a call
+** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
+** Otherwise, if all changes in the changeset have already been visited,
+** SQLITE_DONE is returned.
+**
+** If an error occurs, an SQLite error code is returned. Possible error
+** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
+** SQLITE_NOMEM.
+*/
+SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
+
+/*
+** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
+** is not the case, this function returns [SQLITE_MISUSE].
+**
+** Arguments pOp, pnCol and pzTab may not be NULL. Upon return, three
+** outputs are set through these pointers:
+**
+** *pOp is set to one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
+** depending on the type of change that the iterator currently points to;
+**
+** *pnCol is set to the number of columns in the table affected by the change; and
+**
+** *pzTab is set to point to a nul-terminated utf-8 encoded string containing
+** the name of the table affected by the current change. The buffer remains
+** valid until either sqlite3changeset_next() is called on the iterator
+** or until the conflict-handler function returns.
+**
+** If pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
+** is an indirect change, or false (0) otherwise. See the documentation for
+** [sqlite3session_indirect()] for a description of direct and indirect
+** changes.
+**
+** If no error occurs, SQLITE_OK is returned. If an error does occur, an
+** SQLite error code is returned. The values of the output variables may not
+** be trusted in this case.
+*/
+SQLITE_API int sqlite3changeset_op(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  const char **pzTab,             /* OUT: Pointer to table name */
+  int *pnCol,                     /* OUT: Number of columns in table */
+  int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
+  int *pbIndirect                 /* OUT: True for an 'indirect' change */
+);
+
+/*
+** CAPI3REF: Obtain The Primary Key Definition Of A Table
+** METHOD: sqlite3_changeset_iter
+**
+** For each modified table, a changeset includes the following:
+**
+** <ul>
+**   <li> The number of columns in the table, and
+**   <li> Which of those columns make up the tables PRIMARY KEY.
+** </ul>
+**
+** This function is used to find which columns comprise the PRIMARY KEY of
+** the table modified by the change that iterator pIter currently points to.
+** If successful, *pabPK is set to point to an array of nCol entries, where
+** nCol is the number of columns in the table. Elements of *pabPK are set to
+** 0x01 if the corresponding column is part of the tables primary key, or
+** 0x00 if it is not.
+**
+** If argument pnCol is not NULL, then *pnCol is set to the number of columns
+** in the table.
+**
+** If this function is called when the iterator does not point to a valid
+** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
+** SQLITE_OK is returned and the output variables populated as described
+** above.
+*/
+SQLITE_API int sqlite3changeset_pk(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
+  int *pnCol                      /* OUT: Number of entries in output array */
+);
+
+/*
+** CAPI3REF: Obtain old.* Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
+** Furthermore, it may only be called if the type of change that the iterator
+** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
+** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the vector of
+** original row values stored as part of the UPDATE or DELETE change and
+** returns SQLITE_OK. The name of the function comes from the fact that this
+** is similar to the "old.*" columns available to update or delete triggers.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_old(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
+);
+
+/*
+** CAPI3REF: Obtain new.* Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
+** Furthermore, it may only be called if the type of change that the iterator
+** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
+** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the vector of
+** new row values stored as part of the UPDATE or INSERT change and
+** returns SQLITE_OK. If the change is an UPDATE and does not include
+** a new value for the requested column, *ppValue is set to NULL and
+** SQLITE_OK returned. The name of the function comes from the fact that
+** this is similar to the "new.*" columns available to update or delete
+** triggers.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_new(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
+);
+
+/*
+** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function should only be used with iterator objects passed to a
+** conflict-handler callback by [sqlite3changeset_apply()] with either
+** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
+** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
+** is set to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the
+** "conflicting row" associated with the current conflict-handler callback
+** and returns SQLITE_OK.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_conflict(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: Value from conflicting row */
+);
+
+/*
+** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
+** METHOD: sqlite3_changeset_iter
+**
+** This function may only be called with an iterator passed to an
+** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
+** it sets the output variable to the total number of known foreign key
+** violations in the destination database and returns SQLITE_OK.
+**
+** In all other cases this function returns SQLITE_MISUSE.
+*/
+SQLITE_API int sqlite3changeset_fk_conflicts(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int *pnOut                      /* OUT: Number of FK violations */
+);
+
+
+/*
+** CAPI3REF: Finalize A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function is used to finalize an iterator allocated with
+** [sqlite3changeset_start()].
+**
+** This function should only be called on iterators created using the
+** [sqlite3changeset_start()] function. If an application calls this
+** function with an iterator passed to a conflict-handler by
+** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
+** call has no effect.
+**
+** If an error was encountered within a call to an sqlite3changeset_xxx()
+** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
+** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
+** to that error is returned by this function. Otherwise, SQLITE_OK is
+** returned. This is to allow the following pattern (pseudo-code):
+**
+** <pre>
+**   sqlite3changeset_start();
+**   while( SQLITE_ROW==sqlite3changeset_next() ){
+**     // Do something with change.
+**   }
+**   rc = sqlite3changeset_finalize();
+**   if( rc!=SQLITE_OK ){
+**     // An error has occurred
+**   }
+** </pre>
+*/
+SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
+
+/*
+** CAPI3REF: Invert A Changeset
+**
+** This function is used to "invert" a changeset object. Applying an inverted
+** changeset to a database reverses the effects of applying the uninverted
+** changeset. Specifically:
+**
+** <ul>
+**   <li> Each DELETE change is changed to an INSERT, and
+**   <li> Each INSERT change is changed to a DELETE, and
+**   <li> For each UPDATE change, the old.* and new.* values are exchanged.
+** </ul>
+**
+** This function does not change the order in which changes appear within
+** the changeset. It merely reverses the sense of each individual change.
+**
+** If successful, a pointer to a buffer containing the inverted changeset
+** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
+** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
+** zeroed and an SQLite error code returned.
+**
+** It is the responsibility of the caller to eventually call sqlite3_free()
+** on the *ppOut pointer to free the buffer allocation following a successful
+** call to this function.
+**
+** WARNING/TODO: This function currently assumes that the input is a valid
+** changeset. If it is not, the results are undefined.
+*/
+SQLITE_API int sqlite3changeset_invert(
+  int nIn, const void *pIn,       /* Input changeset */
+  int *pnOut, void **ppOut        /* OUT: Inverse of input */
+);
+
+/*
+** CAPI3REF: Concatenate Two Changeset Objects
+**
+** This function is used to concatenate two changesets, A and B, into a
+** single changeset. The result is a changeset equivalent to applying
+** changeset A followed by changeset B.
+**
+** This function combines the two input changesets using an
+** sqlite3_changegroup object. Calling it produces similar results as the
+** following code fragment:
+**
+** <pre>
+**   sqlite3_changegroup *pGrp;
+**   rc = sqlite3_changegroup_new(&pGrp);
+**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
+**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
+**   if( rc==SQLITE_OK ){
+**     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
+**   }else{
+**     *ppOut = 0;
+**     *pnOut = 0;
+**   }
+** </pre>
+**
+** Refer to the sqlite3_changegroup documentation below for details.
+*/
+SQLITE_API int sqlite3changeset_concat(
+  int nA,                         /* Number of bytes in buffer pA */
+  void *pA,                       /* Pointer to buffer containing changeset A */
+  int nB,                         /* Number of bytes in buffer pB */
+  void *pB,                       /* Pointer to buffer containing changeset B */
+  int *pnOut,                     /* OUT: Number of bytes in output changeset */
+  void **ppOut                    /* OUT: Buffer containing output changeset */
+);
+
+
+/*
+** CAPI3REF: Upgrade the Schema of a Changeset/Patchset
+*/
+SQLITE_API int sqlite3changeset_upgrade(
+  sqlite3 *db,
+  const char *zDb,
+  int nIn, const void *pIn,       /* Input changeset */
+  int *pnOut, void **ppOut        /* OUT: Inverse of input */
+);
+
+
+
+/*
+** CAPI3REF: Changegroup Handle
+**
+** A changegroup is an object used to combine two or more
+** [changesets] or [patchsets]
+*/
+typedef struct sqlite3_changegroup sqlite3_changegroup;
+
+/*
+** CAPI3REF: Create A New Changegroup Object
+** CONSTRUCTOR: sqlite3_changegroup
+**
+** An sqlite3_changegroup object is used to combine two or more changesets
+** (or patchsets) into a single changeset (or patchset). A single changegroup
+** object may combine changesets or patchsets, but not both. The output is
+** always in the same format as the input.
+**
+** If successful, this function returns SQLITE_OK and populates (*pp) with
+** a pointer to a new sqlite3_changegroup object before returning. The caller
+** should eventually free the returned object using a call to
+** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
+** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
+**
+** The usual usage pattern for an sqlite3_changegroup object is as follows:
+**
+** <ul>
+**   <li> It is created using a call to sqlite3changegroup_new().
+**
+**   <li> Zero or more changesets (or patchsets) are added to the object
+**        by calling sqlite3changegroup_add().
+**
+**   <li> The result of combining all input changesets together is obtained
+**        by the application via a call to sqlite3changegroup_output().
+**
+**   <li> The object is deleted using a call to sqlite3changegroup_delete().
+** </ul>
+**
+** Any number of calls to add() and output() may be made between the calls to
+** new() and delete(), and in any order.
+**
+** As well as the regular sqlite3changegroup_add() and
+** sqlite3changegroup_output() functions, also available are the streaming
+** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
+*/
+SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
+
+/*
+** CAPI3REF: Add a Schema to a Changegroup
+** METHOD: sqlite3_changegroup_schema
+**
+** This method may be used to optionally enforce the rule that the changesets
+** added to the changegroup handle must match the schema of database zDb
+** ("main", "temp", or the name of an attached database). If
+** sqlite3changegroup_add() is called to add a changeset that is not compatible
+** with the configured schema, SQLITE_SCHEMA is returned and the changegroup
+** object is left in an undefined state.
+**
+** A changeset schema is considered compatible with the database schema in
+** the same way as for sqlite3changeset_apply(). Specifically, for each
+** table in the changeset, there exists a database table with:
+**
+** <ul>
+**   <li> The name identified by the changeset, and
+**   <li> at least as many columns as recorded in the changeset, and
+**   <li> the primary key columns in the same position as recorded in
+**        the changeset.
+** </ul>
+**
+** The output of the changegroup object always has the same schema as the
+** database nominated using this function. In cases where changesets passed
+** to sqlite3changegroup_add() have fewer columns than the corresponding table
+** in the database schema, these are filled in using the default column
+** values from the database schema. This makes it possible to combined
+** changesets that have different numbers of columns for a single table
+** within a changegroup, provided that they are otherwise compatible.
+*/
+SQLITE_API int sqlite3changegroup_schema(sqlite3_changegroup*, sqlite3*, const char *zDb);
+
+/*
+** CAPI3REF: Add A Changeset To A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** Add all changes within the changeset (or patchset) in buffer pData (size
+** nData bytes) to the changegroup.
+**
+** If the buffer contains a patchset, then all prior calls to this function
+** on the same changegroup object must also have specified patchsets. Or, if
+** the buffer contains a changeset, so must have the earlier calls to this
+** function. Otherwise, SQLITE_ERROR is returned and no changes are added
+** to the changegroup.
+**
+** Rows within the changeset and changegroup are identified by the values in
+** their PRIMARY KEY columns. A change in the changeset is considered to
+** apply to the same row as a change already present in the changegroup if
+** the two rows have the same primary key.
+**
+** Changes to rows that do not already appear in the changegroup are
+** simply copied into it. Or, if both the new changeset and the changegroup
+** contain changes that apply to a single row, the final contents of the
+** changegroup depends on the type of each change, as follows:
+**
+** <table border=1 style="margin-left:8ex;margin-right:8ex">
+**   <tr><th style="white-space:pre">Existing Change  </th>
+**       <th style="white-space:pre">New Change       </th>
+**       <th>Output Change
+**   <tr><td>INSERT <td>INSERT <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>INSERT <td>UPDATE <td>
+**       The INSERT change remains in the changegroup. The values in the
+**       INSERT change are modified as if the row was inserted by the
+**       existing change and then updated according to the new change.
+**   <tr><td>INSERT <td>DELETE <td>
+**       The existing INSERT is removed from the changegroup. The DELETE is
+**       not added.
+**   <tr><td>UPDATE <td>INSERT <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>UPDATE <td>UPDATE <td>
+**       The existing UPDATE remains within the changegroup. It is amended
+**       so that the accompanying values are as if the row was updated once
+**       by the existing change and then again by the new change.
+**   <tr><td>UPDATE <td>DELETE <td>
+**       The existing UPDATE is replaced by the new DELETE within the
+**       changegroup.
+**   <tr><td>DELETE <td>INSERT <td>
+**       If one or more of the column values in the row inserted by the
+**       new change differ from those in the row deleted by the existing
+**       change, the existing DELETE is replaced by an UPDATE within the
+**       changegroup. Otherwise, if the inserted row is exactly the same
+**       as the deleted row, the existing DELETE is simply discarded.
+**   <tr><td>DELETE <td>UPDATE <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>DELETE <td>DELETE <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+** </table>
+**
+** If the new changeset contains changes to a table that is already present
+** in the changegroup, then the number of columns and the position of the
+** primary key columns for the table must be consistent. If this is not the
+** case, this function fails with SQLITE_SCHEMA. Except, if the changegroup
+** object has been configured with a database schema using the
+** sqlite3changegroup_schema() API, then it is possible to combine changesets
+** with different numbers of columns for a single table, provided that
+** they are otherwise compatible.
+**
+** If the input changeset appears to be corrupt and the corruption is
+** detected, SQLITE_CORRUPT is returned. Or, if an out-of-memory condition
+** occurs during processing, this function returns SQLITE_NOMEM.
+**
+** In all cases, if an error occurs the state of the final contents of the
+** changegroup is undefined. If no error occurs, SQLITE_OK is returned.
+*/
+SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
+
+/*
+** CAPI3REF: Add A Single Change To A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** This function adds the single change currently indicated by the iterator
+** passed as the second argument to the changegroup object. The rules for
+** adding the change are just as described for [sqlite3changegroup_add()].
+**
+** If the change is successfully added to the changegroup, SQLITE_OK is
+** returned. Otherwise, an SQLite error code is returned.
+**
+** The iterator must point to a valid entry when this function is called.
+** If it does not, SQLITE_ERROR is returned and no change is added to the
+** changegroup. Additionally, the iterator must not have been opened with
+** the SQLITE_CHANGESETAPPLY_INVERT flag. In this case SQLITE_ERROR is also
+** returned.
+*/
+SQLITE_API int sqlite3changegroup_add_change(
+  sqlite3_changegroup*,
+  sqlite3_changeset_iter*
+);
+
+
+
+/*
+** CAPI3REF: Obtain A Composite Changeset From A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** Obtain a buffer containing a changeset (or patchset) representing the
+** current contents of the changegroup. If the inputs to the changegroup
+** were themselves changesets, the output is a changeset. Or, if the
+** inputs were patchsets, the output is also a patchset.
+**
+** As with the output of the sqlite3session_changeset() and
+** sqlite3session_patchset() functions, all changes related to a single
+** table are grouped together in the output of this function. Tables appear
+** in the same order as for the very first changeset added to the changegroup.
+** If the second or subsequent changesets added to the changegroup contain
+** changes for tables that do not appear in the first changeset, they are
+** appended onto the end of the output changeset, again in the order in
+** which they are first encountered.
+**
+** If an error occurs, an SQLite error code is returned and the output
+** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
+** is returned and the output variables are set to the size of and a
+** pointer to the output buffer, respectively. In this case it is the
+** responsibility of the caller to eventually free the buffer using a
+** call to sqlite3_free().
+*/
+SQLITE_API int sqlite3changegroup_output(
+  sqlite3_changegroup*,
+  int *pnData,                    /* OUT: Size of output buffer in bytes */
+  void **ppData                   /* OUT: Pointer to output buffer */
+);
+
+/*
+** CAPI3REF: Delete A Changegroup Object
+** DESTRUCTOR: sqlite3_changegroup
+*/
+SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
+
+/*
+** CAPI3REF: Apply A Changeset To A Database
+**
+** Apply a changeset or patchset to a database. These functions attempt to
+** update the "main" database attached to handle db with the changes found in
+** the changeset passed via the second and third arguments.
+**
+** The fourth argument (xFilter) passed to these functions is the "filter
+** callback". If it is not NULL, then for each table affected by at least one
+** change in the changeset, the filter callback is invoked with
+** the table name as the second argument, and a copy of the context pointer
+** passed as the sixth argument as the first. If the "filter callback"
+** returns zero, then no attempt is made to apply any changes to the table.
+** Otherwise, if the return value is non-zero or the xFilter argument to
+** is NULL, all changes related to the table are attempted.
+**
+** For each table that is not excluded by the filter callback, this function
+** tests that the target database contains a compatible table. A table is
+** considered compatible if all of the following are true:
+**
+** <ul>
+**   <li> The table has the same name as the name recorded in the
+**        changeset, and
+**   <li> The table has at least as many columns as recorded in the
+**        changeset, and
+**   <li> The table has primary key columns in the same position as
+**        recorded in the changeset.
+** </ul>
+**
+** If there is no compatible table, it is not an error, but none of the
+** changes associated with the table are applied. A warning message is issued
+** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
+** one such warning is issued for each table in the changeset.
+**
+** For each change for which there is a compatible table, an attempt is made
+** to modify the table contents according to the UPDATE, INSERT or DELETE
+** change. If a change cannot be applied cleanly, the conflict handler
+** function passed as the fifth argument to sqlite3changeset_apply() may be
+** invoked. A description of exactly when the conflict handler is invoked for
+** each type of change is below.
+**
+** Unlike the xFilter argument, xConflict may not be passed NULL. The results
+** of passing anything other than a valid function pointer as the xConflict
+** argument are undefined.
+**
+** Each time the conflict handler function is invoked, it must return one
+** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
+** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
+** if the second argument passed to the conflict handler is either
+** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
+** returns an illegal value, any changes already made are rolled back and
+** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
+** actions are taken by sqlite3changeset_apply() depending on the value
+** returned by each invocation of the conflict-handler function. Refer to
+** the documentation for the three
+** [SQLITE_CHANGESET_OMIT|available return values] for details.
+**
+** <dl>
+** <dt>DELETE Changes<dd>
+**   For each DELETE change, the function checks if the target database
+**   contains a row with the same primary key value (or values) as the
+**   original row values stored in the changeset. If it does, and the values
+**   stored in all non-primary key columns also match the values stored in
+**   the changeset the row is deleted from the target database.
+**
+**   If a row with matching primary key values is found, but one or more of
+**   the non-primary key fields contains a value different from the original
+**   row value stored in the changeset, the conflict-handler function is
+**   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
+**   database table has more columns than are recorded in the changeset,
+**   only the values of those non-primary key fields are compared against
+**   the current database contents - any trailing database table columns
+**   are ignored.
+**
+**   If no row with matching primary key values is found in the database,
+**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
+**   passed as the second argument.
+**
+**   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
+**   (which can only happen if a foreign key constraint is violated), the
+**   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
+**   passed as the second argument. This includes the case where the DELETE
+**   operation is attempted because an earlier call to the conflict handler
+**   function returned [SQLITE_CHANGESET_REPLACE].
+**
+** <dt>INSERT Changes<dd>
+**   For each INSERT change, an attempt is made to insert the new row into
+**   the database. If the changeset row contains fewer fields than the
+**   database table, the trailing fields are populated with their default
+**   values.
+**
+**   If the attempt to insert the row fails because the database already
+**   contains a row with the same primary key values, the conflict handler
+**   function is invoked with the second argument set to
+**   [SQLITE_CHANGESET_CONFLICT].
+**
+**   If the attempt to insert the row fails because of some other constraint
+**   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
+**   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
+**   This includes the case where the INSERT operation is re-attempted because
+**   an earlier call to the conflict handler function returned
+**   [SQLITE_CHANGESET_REPLACE].
+**
+** <dt>UPDATE Changes<dd>
+**   For each UPDATE change, the function checks if the target database
+**   contains a row with the same primary key value (or values) as the
+**   original row values stored in the changeset. If it does, and the values
+**   stored in all modified non-primary key columns also match the values
+**   stored in the changeset the row is updated within the target database.
+**
+**   If a row with matching primary key values is found, but one or more of
+**   the modified non-primary key fields contains a value different from an
+**   original row value stored in the changeset, the conflict-handler function
+**   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
+**   UPDATE changes only contain values for non-primary key fields that are
+**   to be modified, only those fields need to match the original values to
+**   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
+**
+**   If no row with matching primary key values is found in the database,
+**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
+**   passed as the second argument.
+**
+**   If the UPDATE operation is attempted, but SQLite returns
+**   SQLITE_CONSTRAINT, the conflict-handler function is invoked with
+**   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
+**   This includes the case where the UPDATE operation is attempted after
+**   an earlier call to the conflict handler function returned
+**   [SQLITE_CHANGESET_REPLACE].
+** </dl>
+**
+** It is safe to execute SQL statements, including those that write to the
+** table that the callback related to, from within the xConflict callback.
+** This can be used to further customize the application's conflict
+** resolution strategy.
+**
+** All changes made by these functions are enclosed in a savepoint transaction.
+** If any other error (aside from a constraint failure when attempting to
+** write to the target database) occurs, then the savepoint transaction is
+** rolled back, restoring the target database to its original state, and an
+** SQLite error code returned.
+**
+** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
+** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
+** may set (*ppRebase) to point to a "rebase" that may be used with the
+** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
+** is set to the size of the buffer in bytes. It is the responsibility of the
+** caller to eventually free any such buffer using sqlite3_free(). The buffer
+** is only allocated and populated if one or more conflicts were encountered
+** while applying the patchset. See comments surrounding the sqlite3_rebaser
+** APIs for further details.
+**
+** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
+** may be modified by passing a combination of
+** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
+**
+** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
+** and therefore subject to change.
+*/
+SQLITE_API int sqlite3changeset_apply(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+);
+SQLITE_API int sqlite3changeset_apply_v2(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase, /* OUT: Rebase data */
+  int flags                       /* SESSION_CHANGESETAPPLY_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3changeset_apply_v2
+**
+** The following flags may passed via the 9th parameter to
+** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
+**
+** <dl>
+** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
+**   Usually, the sessions module encloses all operations performed by
+**   a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
+**   SAVEPOINT is committed if the changeset or patchset is successfully
+**   applied, or rolled back if an error occurs. Specifying this flag
+**   causes the sessions module to omit this savepoint. In this case, if the
+**   caller has an open transaction or savepoint when apply_v2() is called,
+**   it may revert the partially applied changeset by rolling it back.
+**
+** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
+**   Invert the changeset before applying it. This is equivalent to inverting
+**   a changeset using sqlite3changeset_invert() before applying it. It is
+**   an error to specify this flag with a patchset.
+**
+** <dt>SQLITE_CHANGESETAPPLY_IGNORENOOP <dd>
+**   Do not invoke the conflict handler callback for any changes that
+**   would not actually modify the database even if they were applied.
+**   Specifically, this means that the conflict handler is not invoked
+**   for:
+**    <ul>
+**    <li>a delete change if the row being deleted cannot be found,
+**    <li>an update change if the modified fields are already set to
+**        their new values in the conflicting row, or
+**    <li>an insert change if all fields of the conflicting row match
+**        the row being inserted.
+**    </ul>
+**
+** <dt>SQLITE_CHANGESETAPPLY_FKNOACTION <dd>
+**   If this flag it set, then all foreign key constraints in the target
+**   database behave as if they were declared with "ON UPDATE NO ACTION ON
+**   DELETE NO ACTION", even if they are actually CASCADE, RESTRICT, SET NULL
+**   or SET DEFAULT.
+*/
+#define SQLITE_CHANGESETAPPLY_NOSAVEPOINT   0x0001
+#define SQLITE_CHANGESETAPPLY_INVERT        0x0002
+#define SQLITE_CHANGESETAPPLY_IGNORENOOP    0x0004
+#define SQLITE_CHANGESETAPPLY_FKNOACTION    0x0008
+
+/*
+** CAPI3REF: Constants Passed To The Conflict Handler
+**
+** Values that may be passed as the second argument to a conflict-handler.
+**
+** <dl>
+** <dt>SQLITE_CHANGESET_DATA<dd>
+**   The conflict handler is invoked with CHANGESET_DATA as the second argument
+**   when processing a DELETE or UPDATE change if a row with the required
+**   PRIMARY KEY fields is present in the database, but one or more other
+**   (non primary-key) fields modified by the update do not contain the
+**   expected "before" values.
+**
+**   The conflicting row, in this case, is the database row with the matching
+**   primary key.
+**
+** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
+**   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
+**   argument when processing a DELETE or UPDATE change if a row with the
+**   required PRIMARY KEY fields is not present in the database.
+**
+**   There is no conflicting row in this case. The results of invoking the
+**   sqlite3changeset_conflict() API are undefined.
+**
+** <dt>SQLITE_CHANGESET_CONFLICT<dd>
+**   CHANGESET_CONFLICT is passed as the second argument to the conflict
+**   handler while processing an INSERT change if the operation would result
+**   in duplicate primary key values.
+**
+**   The conflicting row in this case is the database row with the matching
+**   primary key.
+**
+** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
+**   If foreign key handling is enabled, and applying a changeset leaves the
+**   database in a state containing foreign key violations, the conflict
+**   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
+**   exactly once before the changeset is committed. If the conflict handler
+**   returns CHANGESET_OMIT, the changes, including those that caused the
+**   foreign key constraint violation, are committed. Or, if it returns
+**   CHANGESET_ABORT, the changeset is rolled back.
+**
+**   No current or conflicting row information is provided. The only function
+**   it is possible to call on the supplied sqlite3_changeset_iter handle
+**   is sqlite3changeset_fk_conflicts().
+**
+** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
+**   If any other constraint violation occurs while applying a change (i.e.
+**   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
+**   invoked with CHANGESET_CONSTRAINT as the second argument.
+**
+**   There is no conflicting row in this case. The results of invoking the
+**   sqlite3changeset_conflict() API are undefined.
+**
+** </dl>
+*/
+#define SQLITE_CHANGESET_DATA        1
+#define SQLITE_CHANGESET_NOTFOUND    2
+#define SQLITE_CHANGESET_CONFLICT    3
+#define SQLITE_CHANGESET_CONSTRAINT  4
+#define SQLITE_CHANGESET_FOREIGN_KEY 5
+
+/*
+** CAPI3REF: Constants Returned By The Conflict Handler
+**
+** A conflict handler callback must return one of the following three values.
+**
+** <dl>
+** <dt>SQLITE_CHANGESET_OMIT<dd>
+**   If a conflict handler returns this value no special action is taken. The
+**   change that caused the conflict is not applied. The session module
+**   continues to the next change in the changeset.
+**
+** <dt>SQLITE_CHANGESET_REPLACE<dd>
+**   This value may only be returned if the second argument to the conflict
+**   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
+**   is not the case, any changes applied so far are rolled back and the
+**   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
+**
+**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
+**   handler, then the conflicting row is either updated or deleted, depending
+**   on the type of change.
+**
+**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
+**   handler, then the conflicting row is removed from the database and a
+**   second attempt to apply the change is made. If this second attempt fails,
+**   the original row is restored to the database before continuing.
+**
+** <dt>SQLITE_CHANGESET_ABORT<dd>
+**   If this value is returned, any changes applied so far are rolled back
+**   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
+** </dl>
+*/
+#define SQLITE_CHANGESET_OMIT       0
+#define SQLITE_CHANGESET_REPLACE    1
+#define SQLITE_CHANGESET_ABORT      2
+
+/*
+** CAPI3REF: Rebasing changesets
+** EXPERIMENTAL
+**
+** Suppose there is a site hosting a database in state S0. And that
+** modifications are made that move that database to state S1 and a
+** changeset recorded (the "local" changeset). Then, a changeset based
+** on S0 is received from another site (the "remote" changeset) and
+** applied to the database. The database is then in state
+** (S1+"remote"), where the exact state depends on any conflict
+** resolution decisions (OMIT or REPLACE) made while applying "remote".
+** Rebasing a changeset is to update it to take those conflict
+** resolution decisions into account, so that the same conflicts
+** do not have to be resolved elsewhere in the network.
+**
+** For example, if both the local and remote changesets contain an
+** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
+**
+**   local:  INSERT INTO t1 VALUES(1, 'v1');
+**   remote: INSERT INTO t1 VALUES(1, 'v2');
+**
+** and the conflict resolution is REPLACE, then the INSERT change is
+** removed from the local changeset (it was overridden). Or, if the
+** conflict resolution was "OMIT", then the local changeset is modified
+** to instead contain:
+**
+**           UPDATE t1 SET b = 'v2' WHERE a=1;
+**
+** Changes within the local changeset are rebased as follows:
+**
+** <dl>
+** <dt>Local INSERT<dd>
+**   This may only conflict with a remote INSERT. If the conflict
+**   resolution was OMIT, then add an UPDATE change to the rebased
+**   changeset. Or, if the conflict resolution was REPLACE, add
+**   nothing to the rebased changeset.
+**
+** <dt>Local DELETE<dd>
+**   This may conflict with a remote UPDATE or DELETE. In both cases the
+**   only possible resolution is OMIT. If the remote operation was a
+**   DELETE, then add no change to the rebased changeset. If the remote
+**   operation was an UPDATE, then the old.* fields of change are updated
+**   to reflect the new.* values in the UPDATE.
+**
+** <dt>Local UPDATE<dd>
+**   This may conflict with a remote UPDATE or DELETE. If it conflicts
+**   with a DELETE, and the conflict resolution was OMIT, then the update
+**   is changed into an INSERT. Any undefined values in the new.* record
+**   from the update change are filled in using the old.* values from
+**   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
+**   the UPDATE change is simply omitted from the rebased changeset.
+**
+**   If conflict is with a remote UPDATE and the resolution is OMIT, then
+**   the old.* values are rebased using the new.* values in the remote
+**   change. Or, if the resolution is REPLACE, then the change is copied
+**   into the rebased changeset with updates to columns also updated by
+**   the conflicting remote UPDATE removed. If this means no columns would
+**   be updated, the change is omitted.
+** </dl>
+**
+** A local change may be rebased against multiple remote changes
+** simultaneously. If a single key is modified by multiple remote
+** changesets, they are combined as follows before the local changeset
+** is rebased:
+**
+** <ul>
+**    <li> If there has been one or more REPLACE resolutions on a
+**         key, it is rebased according to a REPLACE.
+**
+**    <li> If there have been no REPLACE resolutions on a key, then
+**         the local changeset is rebased according to the most recent
+**         of the OMIT resolutions.
+** </ul>
+**
+** Note that conflict resolutions from multiple remote changesets are
+** combined on a per-field basis, not per-row. This means that in the
+** case of multiple remote UPDATE operations, some fields of a single
+** local change may be rebased for REPLACE while others are rebased for
+** OMIT.
+**
+** In order to rebase a local changeset, the remote changeset must first
+** be applied to the local database using sqlite3changeset_apply_v2() and
+** the buffer of rebase information captured. Then:
+**
+** <ol>
+**   <li> An sqlite3_rebaser object is created by calling
+**        sqlite3rebaser_create().
+**   <li> The new object is configured with the rebase buffer obtained from
+**        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
+**        If the local changeset is to be rebased against multiple remote
+**        changesets, then sqlite3rebaser_configure() should be called
+**        multiple times, in the same order that the multiple
+**        sqlite3changeset_apply_v2() calls were made.
+**   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
+**   <li> The sqlite3_rebaser object is deleted by calling
+**        sqlite3rebaser_delete().
+** </ol>
+*/
+typedef struct sqlite3_rebaser sqlite3_rebaser;
+
+/*
+** CAPI3REF: Create a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
+** point to the new object and return SQLITE_OK. Otherwise, if an error
+** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
+** to NULL.
+*/
+SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
+
+/*
+** CAPI3REF: Configure a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Configure the changeset rebaser object to rebase changesets according
+** to the conflict resolutions described by buffer pRebase (size nRebase
+** bytes), which must have been obtained from a previous call to
+** sqlite3changeset_apply_v2().
+*/
+SQLITE_API int sqlite3rebaser_configure(
+  sqlite3_rebaser*,
+  int nRebase, const void *pRebase
+);
+
+/*
+** CAPI3REF: Rebase a changeset
+** EXPERIMENTAL
+**
+** Argument pIn must point to a buffer containing a changeset nIn bytes
+** in size. This function allocates and populates a buffer with a copy
+** of the changeset rebased according to the configuration of the
+** rebaser object passed as the first argument. If successful, (*ppOut)
+** is set to point to the new buffer containing the rebased changeset and
+** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
+** responsibility of the caller to eventually free the new buffer using
+** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
+** are set to zero and an SQLite error code returned.
+*/
+SQLITE_API int sqlite3rebaser_rebase(
+  sqlite3_rebaser*,
+  int nIn, const void *pIn,
+  int *pnOut, void **ppOut
+);
+
+/*
+** CAPI3REF: Delete a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Delete the changeset rebaser object and all associated resources. There
+** should be one call to this function for each successful invocation
+** of sqlite3rebaser_create().
+*/
+SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
+
+/*
+** CAPI3REF: Streaming Versions of API functions.
+**
+** The six streaming API xxx_strm() functions serve similar purposes to the
+** corresponding non-streaming API functions:
+**
+** <table border=1 style="margin-left:8ex;margin-right:8ex">
+**   <tr><th>Streaming function<th>Non-streaming equivalent</th>
+**   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
+**   <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
+**   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
+**   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
+**   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
+**   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
+**   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
+** </table>
+**
+** Non-streaming functions that accept changesets (or patchsets) as input
+** require that the entire changeset be stored in a single buffer in memory.
+** Similarly, those that return a changeset or patchset do so by returning
+** a pointer to a single large buffer allocated using sqlite3_malloc().
+** Normally this is convenient. However, if an application running in a
+** low-memory environment is required to handle very large changesets, the
+** large contiguous memory allocations required can become onerous.
+**
+** In order to avoid this problem, instead of a single large buffer, input
+** is passed to a streaming API functions by way of a callback function that
+** the sessions module invokes to incrementally request input data as it is
+** required. In all cases, a pair of API function parameters such as
+**
+**  <pre>
+**        int nChangeset,
+**        void *pChangeset,
+**  </pre>
+**
+** Is replaced by:
+**
+**  <pre>
+**        int (*xInput)(void *pIn, void *pData, int *pnData),
+**        void *pIn,
+**  </pre>
+**
+** Each time the xInput callback is invoked by the sessions module, the first
+** argument passed is a copy of the supplied pIn context pointer. The second
+** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
+** error occurs the xInput method should copy up to (*pnData) bytes of data
+** into the buffer and set (*pnData) to the actual number of bytes copied
+** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
+** should be set to zero to indicate this. Or, if an error occurs, an SQLite
+** error code should be returned. In all cases, if an xInput callback returns
+** an error, all processing is abandoned and the streaming API function
+** returns a copy of the error code to the caller.
+**
+** In the case of sqlite3changeset_start_strm(), the xInput callback may be
+** invoked by the sessions module at any point during the lifetime of the
+** iterator. If such an xInput callback returns an error, the iterator enters
+** an error state, whereby all subsequent calls to iterator functions
+** immediately fail with the same error code as returned by xInput.
+**
+** Similarly, streaming API functions that return changesets (or patchsets)
+** return them in chunks by way of a callback function instead of via a
+** pointer to a single large buffer. In this case, a pair of parameters such
+** as:
+**
+**  <pre>
+**        int *pnChangeset,
+**        void **ppChangeset,
+**  </pre>
+**
+** Is replaced by:
+**
+**  <pre>
+**        int (*xOutput)(void *pOut, const void *pData, int nData),
+**        void *pOut
+**  </pre>
+**
+** The xOutput callback is invoked zero or more times to return data to
+** the application. The first parameter passed to each call is a copy of the
+** pOut pointer supplied by the application. The second parameter, pData,
+** points to a buffer nData bytes in size containing the chunk of output
+** data being returned. If the xOutput callback successfully processes the
+** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
+** it should return some other SQLite error code. In this case processing
+** is immediately abandoned and the streaming API function returns a copy
+** of the xOutput error code to the application.
+**
+** The sessions module never invokes an xOutput callback with the third
+** parameter set to a value less than or equal to zero. Other than this,
+** no guarantees are made as to the size of the chunks of data returned.
+*/
+SQLITE_API int sqlite3changeset_apply_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+);
+SQLITE_API int sqlite3changeset_apply_v2_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase,
+  int flags
+);
+SQLITE_API int sqlite3changeset_concat_strm(
+  int (*xInputA)(void *pIn, void *pData, int *pnData),
+  void *pInA,
+  int (*xInputB)(void *pIn, void *pData, int *pnData),
+  void *pInB,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changeset_invert_strm(
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changeset_start_strm(
+  sqlite3_changeset_iter **pp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn
+);
+SQLITE_API int sqlite3changeset_start_v2_strm(
+  sqlite3_changeset_iter **pp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int flags
+);
+SQLITE_API int sqlite3session_changeset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3session_patchset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
+    int (*xInput)(void *pIn, void *pData, int *pnData),
+    void *pIn
+);
+SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
+    int (*xOutput)(void *pOut, const void *pData, int nData),
+    void *pOut
+);
+SQLITE_API int sqlite3rebaser_rebase_strm(
+  sqlite3_rebaser *pRebaser,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+
+/*
+** CAPI3REF: Configure global parameters
+**
+** The sqlite3session_config() interface is used to make global configuration
+** changes to the sessions module in order to tune it to the specific needs
+** of the application.
+**
+** The sqlite3session_config() interface is not threadsafe. If it is invoked
+** while any other thread is inside any other sessions method then the
+** results are undefined. Furthermore, if it is invoked after any sessions
+** related objects have been created, the results are also undefined.
+**
+** The first argument to the sqlite3session_config() function must be one
+** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
+** interpretation of the (void*) value passed as the second parameter and
+** the effect of calling this function depends on the value of the first
+** parameter.
+**
+** <dl>
+** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
+**    By default, the sessions module streaming interfaces attempt to input
+**    and output data in approximately 1 KiB chunks. This operand may be used
+**    to set and query the value of this configuration setting. The pointer
+**    passed as the second argument must point to a value of type (int).
+**    If this value is greater than 0, it is used as the new streaming data
+**    chunk size for both input and output. Before returning, the (int) value
+**    pointed to by pArg is set to the final value of the streaming interface
+**    chunk size.
+** </dl>
+**
+** This function returns SQLITE_OK if successful, or an SQLite error code
+** otherwise.
+*/
+SQLITE_API int sqlite3session_config(int op, void *pArg);
+
+/*
+** CAPI3REF: Values for sqlite3session_config().
+*/
+#define SQLITE_SESSION_CONFIG_STRMSIZE 1
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#if 0
+}
+#endif
+
+#endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
+
+/******** End of sqlite3session.h *********/
+/******** Begin file fts5.h *********/
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Interfaces to extend FTS5. Using the interfaces defined in this file,
+** FTS5 may be extended with:
+**
+**     * custom tokenizers, and
+**     * custom auxiliary functions.
+*/
+
+
+#ifndef _FTS5_H
+#define _FTS5_H
+
+
+#if 0
+extern "C" {
+#endif
+
+/*************************************************************************
+** CUSTOM AUXILIARY FUNCTIONS
+**
+** Virtual table implementations may overload SQL functions by implementing
+** the sqlite3_module.xFindFunction() method.
+*/
+
+typedef struct Fts5ExtensionApi Fts5ExtensionApi;
+typedef struct Fts5Context Fts5Context;
+typedef struct Fts5PhraseIter Fts5PhraseIter;
+
+typedef void (*fts5_extension_function)(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+);
+
+struct Fts5PhraseIter {
+  const unsigned char *a;
+  const unsigned char *b;
+};
+
+/*
+** EXTENSION API FUNCTIONS
+**
+** xUserData(pFts):
+**   Return a copy of the pUserData pointer passed to the xCreateFunction()
+**   API when the extension function was registered.
+**
+** xColumnTotalSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the FTS5 table. Or, if iCol is
+**   non-negative but less than the number of columns in the table, return
+**   the total number of tokens in column iCol, considering all rows in
+**   the FTS5 table.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+** xColumnCount(pFts):
+**   Return the number of columns in the table.
+**
+** xColumnSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the current row. Or, if iCol is
+**   non-negative but less than the number of columns in the table, set
+**   *pnToken to the number of tokens in column iCol of the current row.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+**   This function may be quite inefficient if used with an FTS5 table
+**   created with the "columnsize=0" option.
+**
+** xColumnText:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the text of column iCol of
+**   the current document. If successful, (*pz) is set to point to a buffer
+**   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
+**   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
+**   if an error occurs, an SQLite error code is returned and the final values
+**   of (*pz) and (*pn) are undefined.
+**
+** xPhraseCount:
+**   Returns the number of phrases in the current query expression.
+**
+** xPhraseSize:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of phrases in the current query, as returned by xPhraseCount,
+**   0 is returned. Otherwise, this function returns the number of tokens in
+**   phrase iPhrase of the query. Phrases are numbered starting from zero.
+**
+** xInstCount:
+**   Set *pnInst to the total number of occurrences of all phrases within
+**   the query within the current row. Return SQLITE_OK if successful, or
+**   an error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always returns 0.
+**
+** xInst:
+**   Query for the details of phrase match iIdx within the current row.
+**   Phrase matches are numbered starting from zero, so the iIdx argument
+**   should be greater than or equal to zero and smaller than the value
+**   output by xInstCount(). If iIdx is less than zero or greater than
+**   or equal to the value returned by xInstCount(), SQLITE_RANGE is returned.
+**
+**   Otherwise, output parameter *piPhrase is set to the phrase number, *piCol
+**   to the column in which it occurs and *piOff the token offset of the
+**   first token of the phrase. SQLITE_OK is returned if successful, or an
+**   error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xRowid:
+**   Returns the rowid of the current row.
+**
+** xTokenize:
+**   Tokenize text using the tokenizer belonging to the FTS5 table.
+**
+** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
+**   This API function is used to query the FTS table for phrase iPhrase
+**   of the current query. Specifically, a query equivalent to:
+**
+**       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
+**
+**   with $p set to a phrase equivalent to the phrase iPhrase of the
+**   current query is executed. Any column filter that applies to
+**   phrase iPhrase of the current query is included in $p. For each
+**   row visited, the callback function passed as the fourth argument
+**   is invoked. The context and API objects passed to the callback
+**   function may be used to access the properties of each matched row.
+**   Invoking Api.xUserData() returns a copy of the pointer passed as
+**   the third argument to pUserData.
+**
+**   If parameter iPhrase is less than zero, or greater than or equal to
+**   the number of phrases in the query, as returned by xPhraseCount(),
+**   this function returns SQLITE_RANGE.
+**
+**   If the callback function returns any value other than SQLITE_OK, the
+**   query is abandoned and the xQueryPhrase function returns immediately.
+**   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
+**   Otherwise, the error code is propagated upwards.
+**
+**   If the query runs to completion without incident, SQLITE_OK is returned.
+**   Or, if some error occurs before the query completes or is aborted by
+**   the callback, an SQLite error code is returned.
+**
+**
+** xSetAuxdata(pFts5, pAux, xDelete)
+**
+**   Save the pointer passed as the second argument as the extension function's
+**   "auxiliary data". The pointer may then be retrieved by the current or any
+**   future invocation of the same fts5 extension function made as part of
+**   the same MATCH query using the xGetAuxdata() API.
+**
+**   Each extension function is allocated a single auxiliary data slot for
+**   each FTS query (MATCH expression). If the extension function is invoked
+**   more than once for a single FTS query, then all invocations share a
+**   single auxiliary data context.
+**
+**   If there is already an auxiliary data pointer when this function is
+**   invoked, then it is replaced by the new pointer. If an xDelete callback
+**   was specified along with the original pointer, it is invoked at this
+**   point.
+**
+**   The xDelete callback, if one is specified, is also invoked on the
+**   auxiliary data pointer after the FTS5 query has finished.
+**
+**   If an error (e.g. an OOM condition) occurs within this function,
+**   the auxiliary data is set to NULL and an error code returned. If the
+**   xDelete parameter was not NULL, it is invoked on the auxiliary data
+**   pointer before returning.
+**
+**
+** xGetAuxdata(pFts5, bClear)
+**
+**   Returns the current auxiliary data pointer for the fts5 extension
+**   function. See the xSetAuxdata() method for details.
+**
+**   If the bClear argument is non-zero, then the auxiliary data is cleared
+**   (set to NULL) before this function returns. In this case the xDelete,
+**   if any, is not invoked.
+**
+**
+** xRowCount(pFts5, pnRow)
+**
+**   This function is used to retrieve the total number of rows in the table.
+**   In other words, the same value that would be returned by:
+**
+**        SELECT count(*) FROM ftstable;
+**
+** xPhraseFirst()
+**   This function is used, along with type Fts5PhraseIter and the xPhraseNext
+**   method, to iterate through all instances of a single query phrase within
+**   the current row. This is the same information as is accessible via the
+**   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
+**   to use, this API may be faster under some circumstances. To iterate
+**   through instances of phrase iPhrase, use the following code:
+**
+**       Fts5PhraseIter iter;
+**       int iCol, iOff;
+**       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
+**           iCol>=0;
+**           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
+**       ){
+**         // An instance of phrase iPhrase at offset iOff of column iCol
+**       }
+**
+**   The Fts5PhraseIter structure is defined above. Applications should not
+**   modify this structure directly - it should only be used as shown above
+**   with the xPhraseFirst() and xPhraseNext() API methods (and by
+**   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always iterates
+**   through an empty set (all calls to xPhraseFirst() set iCol to -1).
+**
+**   In all cases, matches are visited in (column ASC, offset ASC) order.
+**   i.e. all those in column 0, sorted by offset, followed by those in
+**   column 1, etc.
+**
+** xPhraseNext()
+**   See xPhraseFirst above.
+**
+** xPhraseFirstColumn()
+**   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
+**   and xPhraseNext() APIs described above. The difference is that instead
+**   of iterating through all instances of a phrase in the current row, these
+**   APIs are used to iterate through the set of columns in the current row
+**   that contain one or more instances of a specified phrase. For example:
+**
+**       Fts5PhraseIter iter;
+**       int iCol;
+**       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
+**           iCol>=0;
+**           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
+**       ){
+**         // Column iCol contains at least one instance of phrase iPhrase
+**       }
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" option. If the FTS5 table is created with either
+**   "detail=none" "content=" option (i.e. if it is a contentless table),
+**   then this API always iterates through an empty set (all calls to
+**   xPhraseFirstColumn() set iCol to -1).
+**
+**   The information accessed using this API and its companion
+**   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
+**   (or xInst/xInstCount). The chief advantage of this API is that it is
+**   significantly more efficient than those alternatives when used with
+**   "detail=column" tables.
+**
+** xPhraseNextColumn()
+**   See xPhraseFirstColumn above.
+**
+** xQueryToken(pFts5, iPhrase, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase iPhrase of the current
+**   query. Before returning, output parameter *ppToken is set to point
+**   to a buffer containing the requested token, and *pnToken to the
+**   size of this buffer in bytes.
+**
+**   If iPhrase or iToken are less than zero, or if iPhrase is greater than
+**   or equal to the number of phrases in the query as reported by
+**   xPhraseCount(), or if iToken is equal to or greater than the number of
+**   tokens in the phrase, SQLITE_RANGE is returned and *ppToken and *pnToken
+     are both zeroed.
+**
+**   The output text is not a copy of the query text that specified the
+**   token. It is the output of the tokenizer module. For tokendata=1
+**   tables, this includes any embedded 0x00 and trailing data.
+**
+** xInstToken(pFts5, iIdx, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase hit iIdx within the
+**   current row. If iIdx is less than zero or greater than or equal to the
+**   value returned by xInstCount(), SQLITE_RANGE is returned.  Otherwise,
+**   output variable (*ppToken) is set to point to a buffer containing the
+**   matching document token, and (*pnToken) to the size of that buffer in
+**   bytes.
+**
+**   The output text is not a copy of the document text that was tokenized.
+**   It is the output of the tokenizer module. For tokendata=1 tables, this
+**   includes any embedded 0x00 and trailing data.
+**
+**   This API may be slow in some cases if the token identified by parameters
+**   iIdx and iToken matched a prefix token in the query. In most cases, the
+**   first call to this API for each prefix token in the query is forced
+**   to scan the portion of the full-text index that matches the prefix
+**   token to collect the extra data required by this API. If the prefix
+**   token matches a large number of token instances in the document set,
+**   this may be a performance problem.
+**
+**   If the user knows in advance that a query may use this API for a
+**   prefix token, FTS5 may be configured to collect all required data as part
+**   of the initial querying of the full-text index, avoiding the second scan
+**   entirely. This also causes prefix queries that do not use this API to
+**   run more slowly and use more memory. FTS5 may be configured in this way
+**   either on a per-table basis using the [FTS5 insttoken | 'insttoken']
+**   option, or on a per-query basis using the
+**   [fts5_insttoken | fts5_insttoken()] user function.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xColumnLocale(pFts5, iIdx, pzLocale, pnLocale)
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the locale associated
+**   with column iCol of the current row. Usually, there is no associated
+**   locale, and output parameters (*pzLocale) and (*pnLocale) are set
+**   to NULL and 0, respectively. However, if the fts5_locale() function
+**   was used to associate a locale with the value when it was inserted
+**   into the fts5 table, then (*pzLocale) is set to point to a nul-terminated
+**   buffer containing the name of the locale in utf-8 encoding. (*pnLocale)
+**   is set to the size in bytes of the buffer, not including the
+**   nul-terminator.
+**
+**   If successful, SQLITE_OK is returned. Or, if an error occurs, an
+**   SQLite error code is returned. The final value of the output parameters
+**   is undefined in this case.
+**
+** xTokenize_v2:
+**   Tokenize text using the tokenizer belonging to the FTS5 table. This
+**   API is the same as the xTokenize() API, except that it allows a tokenizer
+**   locale to be specified.
+*/
+struct Fts5ExtensionApi {
+  int iVersion;                   /* Currently always set to 4 */
+
+  void *(*xUserData)(Fts5Context*);
+
+  int (*xColumnCount)(Fts5Context*);
+  int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
+  int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
+
+  int (*xTokenize)(Fts5Context*,
+    const char *pText, int nText, /* Text to tokenize */
+    void *pCtx,                   /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+
+  int (*xPhraseCount)(Fts5Context*);
+  int (*xPhraseSize)(Fts5Context*, int iPhrase);
+
+  int (*xInstCount)(Fts5Context*, int *pnInst);
+  int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
+
+  sqlite3_int64 (*xRowid)(Fts5Context*);
+  int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
+
+  int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
+    int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
+  );
+  int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
+  void *(*xGetAuxdata)(Fts5Context*, int bClear);
+
+  int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
+  void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
+
+  int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
+  void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
+
+  /* Below this point are iVersion>=3 only */
+  int (*xQueryToken)(Fts5Context*,
+      int iPhrase, int iToken,
+      const char **ppToken, int *pnToken
+  );
+  int (*xInstToken)(Fts5Context*, int iIdx, int iToken, const char**, int*);
+
+  /* Below this point are iVersion>=4 only */
+  int (*xColumnLocale)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xTokenize_v2)(Fts5Context*,
+    const char *pText, int nText,      /* Text to tokenize */
+    const char *pLocale, int nLocale,  /* Locale to pass to tokenizer */
+    void *pCtx,                        /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+};
+
+/*
+** CUSTOM AUXILIARY FUNCTIONS
+*************************************************************************/
+
+/*************************************************************************
+** CUSTOM TOKENIZERS
+**
+** Applications may also register custom tokenizer types. A tokenizer
+** is registered by providing fts5 with a populated instance of the
+** following structure. All structure methods must be defined, setting
+** any member of the fts5_tokenizer struct to NULL leads to undefined
+** behaviour. The structure methods are expected to function as follows:
+**
+** xCreate:
+**   This function is used to allocate and initialize a tokenizer instance.
+**   A tokenizer instance is required to actually tokenize text.
+**
+**   The first argument passed to this function is a copy of the (void*)
+**   pointer provided by the application when the fts5_tokenizer_v2 object
+**   was registered with FTS5 (the third argument to xCreateTokenizer()).
+**   The second and third arguments are an array of nul-terminated strings
+**   containing the tokenizer arguments, if any, specified following the
+**   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
+**   to create the FTS5 table.
+**
+**   The final argument is an output variable. If successful, (*ppOut)
+**   should be set to point to the new tokenizer handle and SQLITE_OK
+**   returned. If an error occurs, some value other than SQLITE_OK should
+**   be returned. In this case, fts5 assumes that the final value of *ppOut
+**   is undefined.
+**
+** xDelete:
+**   This function is invoked to delete a tokenizer handle previously
+**   allocated using xCreate(). Fts5 guarantees that this function will
+**   be invoked exactly once for each successful call to xCreate().
+**
+** xTokenize:
+**   This function is expected to tokenize the nText byte string indicated
+**   by argument pText. pText may or may not be nul-terminated. The first
+**   argument passed to this function is a pointer to an Fts5Tokenizer object
+**   returned by an earlier call to xCreate().
+**
+**   The third argument indicates the reason that FTS5 is requesting
+**   tokenization of the supplied text. This is always one of the following
+**   four values:
+**
+**   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
+**            or removed from the FTS table. The tokenizer is being invoked to
+**            determine the set of tokens to add to (or delete from) the
+**            FTS index.
+**
+**       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
+**            against the FTS index. The tokenizer is being called to tokenize
+**            a bareword or quoted string specified as part of the query.
+**
+**       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
+**            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
+**            followed by a "*" character, indicating that the last token
+**            returned by the tokenizer will be treated as a token prefix.
+**
+**       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
+**            satisfy an fts5_api.xTokenize() request made by an auxiliary
+**            function. Or an fts5_api.xColumnSize() request made by the same
+**            on a columnsize=0 database.
+**   </ul>
+**
+**   The sixth and seventh arguments passed to xTokenize() - pLocale and
+**   nLocale - are a pointer to a buffer containing the locale to use for
+**   tokenization (e.g. "en_US") and its size in bytes, respectively. The
+**   pLocale buffer is not nul-terminated. pLocale may be passed NULL (in
+**   which case nLocale is always 0) to indicate that the tokenizer should
+**   use its default locale.
+**
+**   For each token in the input string, the supplied callback xToken() must
+**   be invoked. The first argument to it should be a copy of the pointer
+**   passed as the second argument to xTokenize(). The third and fourth
+**   arguments are a pointer to a buffer containing the token text, and the
+**   size of the token in bytes. The 4th and 5th arguments are the byte offsets
+**   of the first byte of and first byte immediately following the text from
+**   which the token is derived within the input.
+**
+**   The second argument passed to the xToken() callback ("tflags") should
+**   normally be set to 0. The exception is if the tokenizer supports
+**   synonyms. In this case see the discussion below for details.
+**
+**   FTS5 assumes the xToken() callback is invoked for each token in the
+**   order that they occur within the input text.
+**
+**   If an xToken() callback returns any value other than SQLITE_OK, then
+**   the tokenization should be abandoned and the xTokenize() method should
+**   immediately return a copy of the xToken() return value. Or, if the
+**   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
+**   if an error occurs with the xTokenize() implementation itself, it
+**   may abandon the tokenization and return any error code other than
+**   SQLITE_OK or SQLITE_DONE.
+**
+**   If the tokenizer is registered using an fts5_tokenizer_v2 object,
+**   then the xTokenize() method has two additional arguments - pLocale
+**   and nLocale. These specify the locale that the tokenizer should use
+**   for the current request. If pLocale and nLocale are both 0, then the
+**   tokenizer should use its default locale. Otherwise, pLocale points to
+**   an nLocale byte buffer containing the name of the locale to use as utf-8
+**   text. pLocale is not nul-terminated.
+**
+** FTS5_TOKENIZER
+**
+** There is also an fts5_tokenizer object. This is an older, deprecated,
+** version of fts5_tokenizer_v2. It is similar except that:
+**
+**  <ul>
+**    <li> There is no "iVersion" field, and
+**    <li> The xTokenize() method does not take a locale argument.
+**  </ul>
+**
+** Legacy fts5_tokenizer tokenizers must be registered using the
+** legacy xCreateTokenizer() function, instead of xCreateTokenizer_v2().
+**
+** Tokenizer implementations registered using either API may be retrieved
+** using both xFindTokenizer() and xFindTokenizer_v2().
+**
+** SYNONYM SUPPORT
+**
+**   Custom tokenizers may also support synonyms. Consider a case in which a
+**   user wishes to query for a phrase such as "first place". Using the
+**   built-in tokenizers, the FTS5 query 'first + place' will match instances
+**   of "first place" within the document set, but not alternative forms
+**   such as "1st place". In some applications, it would be better to match
+**   all instances of "first place" or "1st place" regardless of which form
+**   the user specified in the MATCH query text.
+**
+**   There are several ways to approach this in FTS5:
+**
+**   <ol><li> By mapping all synonyms to a single token. In this case, using
+**            the above example, this means that the tokenizer returns the
+**            same token for inputs "first" and "1st". Say that token is in
+**            fact "first", so that when the user inserts the document "I won
+**            1st place" entries are added to the index for tokens "i", "won",
+**            "first" and "place". If the user then queries for '1st + place',
+**            the tokenizer substitutes "first" for "1st" and the query works
+**            as expected.
+**
+**       <li> By querying the index for all synonyms of each query term
+**            separately. In this case, when tokenizing query text, the
+**            tokenizer may provide multiple synonyms for a single term
+**            within the document. FTS5 then queries the index for each
+**            synonym individually. For example, faced with the query:
+**
+**   <codeblock>
+**     ... MATCH 'first place'</codeblock>
+**
+**            the tokenizer offers both "1st" and "first" as synonyms for the
+**            first token in the MATCH query and FTS5 effectively runs a query
+**            similar to:
+**
+**   <codeblock>
+**     ... MATCH '(first OR 1st) place'</codeblock>
+**
+**            except that, for the purposes of auxiliary functions, the query
+**            still appears to contain just two phrases - "(first OR 1st)"
+**            being treated as a single phrase.
+**
+**       <li> By adding multiple synonyms for a single term to the FTS index.
+**            Using this method, when tokenizing document text, the tokenizer
+**            provides multiple synonyms for each token. So that when a
+**            document such as "I won first place" is tokenized, entries are
+**            added to the FTS index for "i", "won", "first", "1st" and
+**            "place".
+**
+**            This way, even if the tokenizer does not provide synonyms
+**            when tokenizing query text (it should not - to do so would be
+**            inefficient), it doesn't matter if the user queries for
+**            'first + place' or '1st + place', as there are entries in the
+**            FTS index corresponding to both forms of the first token.
+**   </ol>
+**
+**   Whether it is parsing document or query text, any call to xToken that
+**   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
+**   is considered to supply a synonym for the previous token. For example,
+**   when parsing the document "I won first place", a tokenizer that supports
+**   synonyms would call xToken() 5 times, as follows:
+**
+**   <codeblock>
+**       xToken(pCtx, 0, "i",                      1,  0,  1);
+**       xToken(pCtx, 0, "won",                    3,  2,  5);
+**       xToken(pCtx, 0, "first",                  5,  6, 11);
+**       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
+**       xToken(pCtx, 0, "place",                  5, 12, 17);
+**</codeblock>
+**
+**   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
+**   xToken() is called. Multiple synonyms may be specified for a single token
+**   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
+**   There is no limit to the number of synonyms that may be provided for a
+**   single token.
+**
+**   In many cases, method (1) above is the best approach. It does not add
+**   extra data to the FTS index or require FTS5 to query for multiple terms,
+**   so it is efficient in terms of disk space and query speed. However, it
+**   does not support prefix queries very well. If, as suggested above, the
+**   token "first" is substituted for "1st" by the tokenizer, then the query:
+**
+**   <codeblock>
+**     ... MATCH '1s*'</codeblock>
+**
+**   will not match documents that contain the token "1st" (as the tokenizer
+**   will probably not map "1s" to any prefix of "first").
+**
+**   For full prefix support, method (3) may be preferred. In this case,
+**   because the index contains entries for both "first" and "1st", prefix
+**   queries such as 'fi*' or '1s*' will match correctly. However, because
+**   extra entries are added to the FTS index, this method uses more space
+**   within the database.
+**
+**   Method (2) offers a midpoint between (1) and (3). Using this method,
+**   a query such as '1s*' will match documents that contain the literal
+**   token "1st", but not "first" (assuming the tokenizer is not able to
+**   provide synonyms for prefixes). However, a non-prefix query like '1st'
+**   will match against "1st" and "first". This method does not require
+**   extra disk space, as no extra entries are added to the FTS index.
+**   On the other hand, it may require more CPU cycles to run MATCH queries,
+**   as separate queries of the FTS index are required for each synonym.
+**
+**   When using methods (2) or (3), it is important that the tokenizer only
+**   provide synonyms when tokenizing document text (method (3)) or query
+**   text (method (2)), not both. Doing so will not cause any errors, but is
+**   inefficient.
+*/
+typedef struct Fts5Tokenizer Fts5Tokenizer;
+typedef struct fts5_tokenizer_v2 fts5_tokenizer_v2;
+struct fts5_tokenizer_v2 {
+  int iVersion;             /* Currently always 2 */
+
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      const char *pLocale, int nLocale,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+/*
+** New code should use the fts5_tokenizer_v2 type to define tokenizer
+** implementations. The following type is included for legacy applications
+** that still use it.
+*/
+typedef struct fts5_tokenizer fts5_tokenizer;
+struct fts5_tokenizer {
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+
+/* Flags that may be passed as the third argument to xTokenize() */
+#define FTS5_TOKENIZE_QUERY     0x0001
+#define FTS5_TOKENIZE_PREFIX    0x0002
+#define FTS5_TOKENIZE_DOCUMENT  0x0004
+#define FTS5_TOKENIZE_AUX       0x0008
+
+/* Flags that may be passed by the tokenizer implementation back to FTS5
+** as the third argument to the supplied xToken callback. */
+#define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
+
+/*
+** END OF CUSTOM TOKENIZERS
+*************************************************************************/
+
+/*************************************************************************
+** FTS5 EXTENSION REGISTRATION API
+*/
+typedef struct fts5_api fts5_api;
+struct fts5_api {
+  int iVersion;                   /* Currently always set to 3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer *pTokenizer
+  );
+
+  /* Create a new auxiliary function */
+  int (*xCreateFunction)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_extension_function xFunction,
+    void (*xDestroy)(void*)
+  );
+
+  /* APIs below this point are only available if iVersion>=3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer_v2 *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer_v2 **ppTokenizer
+  );
+};
+
+/*
+** END OF REGISTRATION API
+*************************************************************************/
+
+#if 0
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* _FTS5_H */
+
+/******** End of fts5.h *********/
+#endif /* SQLITE3_H */
+
+/************** End of sqlite3.h *********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/*
+** Reuse the STATIC_LRU for mutex access to sqlite3_temp_directory.
+*/
+#define SQLITE_MUTEX_STATIC_TEMPDIR SQLITE_MUTEX_STATIC_VFS1
+
+/*
+** Include the configuration header output by 'configure' if we're using the
+** autoconf-based build
+*/
+#if defined(_HAVE_SQLITE_CONFIG_H) && !defined(SQLITECONFIG_H)
+#include "sqlite_cfg.h"
+#define SQLITECONFIG_H 1
+#endif
+
+/************** Include sqliteLimit.h in the middle of sqliteInt.h ***********/
+/************** Begin file sqliteLimit.h *************************************/
+/*
+** 2007 May 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file defines various limits of what SQLite can process.
+*/
+
+/*
+** The maximum length of a TEXT or BLOB in bytes.   This also
+** limits the size of a row in a table or index.
+**
+** The hard limit is the ability of a 32-bit signed integer
+** to count the size: 2^31-1 or 2147483647.
+*/
+#ifndef SQLITE_MAX_LENGTH
+# define SQLITE_MAX_LENGTH 1000000000
+#endif
+#define SQLITE_MIN_LENGTH 30   /* Minimum value for the length limit */
+
+/*
+** This is the maximum number of
+**
+**    * Columns in a table
+**    * Columns in an index
+**    * Columns in a view
+**    * Terms in the SET clause of an UPDATE statement
+**    * Terms in the result set of a SELECT statement
+**    * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement.
+**    * Terms in the VALUES clause of an INSERT statement
+**
+** The hard upper limit here is 32676.  Most database people will
+** tell you that in a well-normalized database, you usually should
+** not have more than a dozen or so columns in any table.  And if
+** that is the case, there is no point in having more than a few
+** dozen values in any of the other situations described above.
+*/
+#ifndef SQLITE_MAX_COLUMN
+# define SQLITE_MAX_COLUMN 2000
+#endif
+
+/*
+** The maximum length of a single SQL statement in bytes.
+**
+** It used to be the case that setting this value to zero would
+** turn the limit off.  That is no longer true.  It is not possible
+** to turn this limit off.
+*/
+#ifndef SQLITE_MAX_SQL_LENGTH
+# define SQLITE_MAX_SQL_LENGTH 1000000000
+#endif
+
+/*
+** The maximum depth of an expression tree. This is limited to
+** some extent by SQLITE_MAX_SQL_LENGTH. But sometime you might
+** want to place more severe limits on the complexity of an
+** expression. A value of 0 means that there is no limit.
+*/
+#ifndef SQLITE_MAX_EXPR_DEPTH
+# define SQLITE_MAX_EXPR_DEPTH 1000
+#endif
+
+/*
+** The maximum number of terms in a compound SELECT statement.
+** The code generator for compound SELECT statements does one
+** level of recursion for each term.  A stack overflow can result
+** if the number of terms is too large.  In practice, most SQL
+** never has more than 3 or 4 terms.  Use a value of 0 to disable
+** any limit on the number of terms in a compound SELECT.
+*/
+#ifndef SQLITE_MAX_COMPOUND_SELECT
+# define SQLITE_MAX_COMPOUND_SELECT 500
+#endif
+
+/*
+** The maximum number of opcodes in a VDBE program.
+** Not currently enforced.
+*/
+#ifndef SQLITE_MAX_VDBE_OP
+# define SQLITE_MAX_VDBE_OP 250000000
+#endif
+
+/*
+** The maximum number of arguments to an SQL function.
+**
+** This value has a hard upper limit of 32767 due to storage
+** constraints (it needs to fit inside a i16).  We keep it
+** lower than that to prevent abuse.
+*/
+#ifndef SQLITE_MAX_FUNCTION_ARG
+# define SQLITE_MAX_FUNCTION_ARG 1000
+#endif
+
+/*
+** The suggested maximum number of in-memory pages to use for
+** the main database table and for temporary tables.
+**
+** IMPLEMENTATION-OF: R-30185-15359 The default suggested cache size is -2000,
+** which means the cache size is limited to 2048000 bytes of memory.
+** IMPLEMENTATION-OF: R-48205-43578 The default suggested cache size can be
+** altered using the SQLITE_DEFAULT_CACHE_SIZE compile-time options.
+*/
+#ifndef SQLITE_DEFAULT_CACHE_SIZE
+# define SQLITE_DEFAULT_CACHE_SIZE  -2000
+#endif
+
+/*
+** The default number of frames to accumulate in the log file before
+** checkpointing the database in WAL mode.
+*/
+#ifndef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT
+# define SQLITE_DEFAULT_WAL_AUTOCHECKPOINT  1000
+#endif
+
+/*
+** The maximum number of attached databases.  This must be between 0
+** and 125.  The upper bound of 125 is because the attached databases are
+** counted using a signed 8-bit integer which has a maximum value of 127
+** and we have to allow 2 extra counts for the "main" and "temp" databases.
+*/
+#ifndef SQLITE_MAX_ATTACHED
+# define SQLITE_MAX_ATTACHED 10
+#endif
+
+
+/*
+** The maximum value of a ?nnn wildcard that the parser will accept.
+** If the value exceeds 32767 then extra space is required for the Expr
+** structure.  But otherwise, we believe that the number can be as large
+** as a signed 32-bit integer can hold.
+*/
+#ifndef SQLITE_MAX_VARIABLE_NUMBER
+# define SQLITE_MAX_VARIABLE_NUMBER 32766
+#endif
+
+/* Maximum page size.  The upper bound on this value is 65536.  This a limit
+** imposed by the use of 16-bit offsets within each page.
+**
+** Earlier versions of SQLite allowed the user to change this value at
+** compile time. This is no longer permitted, on the grounds that it creates
+** a library that is technically incompatible with an SQLite library
+** compiled with a different limit. If a process operating on a database
+** with a page-size of 65536 bytes crashes, then an instance of SQLite
+** compiled with the default page-size limit will not be able to rollback
+** the aborted transaction. This could lead to database corruption.
+*/
+#ifdef SQLITE_MAX_PAGE_SIZE
+# undef SQLITE_MAX_PAGE_SIZE
+#endif
+#define SQLITE_MAX_PAGE_SIZE 65536
+
+
+/*
+** The default size of a database page.
+*/
+#ifndef SQLITE_DEFAULT_PAGE_SIZE
+# define SQLITE_DEFAULT_PAGE_SIZE 4096
+#endif
+#if SQLITE_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
+# undef SQLITE_DEFAULT_PAGE_SIZE
+# define SQLITE_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
+#endif
+
+/*
+** Ordinarily, if no value is explicitly provided, SQLite creates databases
+** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain
+** device characteristics (sector-size and atomic write() support),
+** SQLite may choose a larger value. This constant is the maximum value
+** SQLite will choose on its own.
+*/
+#ifndef SQLITE_MAX_DEFAULT_PAGE_SIZE
+# define SQLITE_MAX_DEFAULT_PAGE_SIZE 8192
+#endif
+#if SQLITE_MAX_DEFAULT_PAGE_SIZE>SQLITE_MAX_PAGE_SIZE
+# undef SQLITE_MAX_DEFAULT_PAGE_SIZE
+# define SQLITE_MAX_DEFAULT_PAGE_SIZE SQLITE_MAX_PAGE_SIZE
+#endif
+
+
+/*
+** Maximum number of pages in one database file.
+**
+** This is really just the default value for the max_page_count pragma.
+** This value can be lowered (or raised) at run-time using that the
+** max_page_count macro.
+*/
+#ifndef SQLITE_MAX_PAGE_COUNT
+# define SQLITE_MAX_PAGE_COUNT 0xfffffffe /* 4294967294 */
+#endif
+
+/*
+** Maximum length (in bytes) of the pattern in a LIKE or GLOB
+** operator.
+*/
+#ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
+# define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
+#endif
+
+/*
+** Maximum depth of recursion for triggers.
+**
+** A value of 1 means that a trigger program will not be able to itself
+** fire any triggers. A value of 0 means that no trigger programs at all
+** may be executed.
+*/
+#ifndef SQLITE_MAX_TRIGGER_DEPTH
+# define SQLITE_MAX_TRIGGER_DEPTH 1000
+#endif
+
+/************** End of sqliteLimit.h *****************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/* Disable nuisance warnings on Borland compilers */
+#if defined(__BORLANDC__)
+#pragma warn -rch /* unreachable code */
+#pragma warn -ccc /* Condition is always true or false */
+#pragma warn -aus /* Assigned value is never used */
+#pragma warn -csu /* Comparing signed and unsigned */
+#pragma warn -spa /* Suspicious pointer arithmetic */
+#endif
+
+/*
+** A few places in the code require atomic load/store of aligned
+** integer values.
+*/
+#ifndef __has_extension
+# define __has_extension(x) 0     /* compatibility with non-clang compilers */
+#endif
+#if GCC_VERSION>=4007000 || __has_extension(c_atomic)
+# define SQLITE_ATOMIC_INTRINSICS 1
+# define AtomicLoad(PTR)       __atomic_load_n((PTR),__ATOMIC_RELAXED)
+# define AtomicStore(PTR,VAL)  __atomic_store_n((PTR),(VAL),__ATOMIC_RELAXED)
+#else
+# define SQLITE_ATOMIC_INTRINSICS 0
+# define AtomicLoad(PTR)       (*(PTR))
+# define AtomicStore(PTR,VAL)  (*(PTR) = (VAL))
+#endif
+
+/*
+** Include standard header files as necessary
+*/
+#ifdef HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+
+/*
+** The following macros are used to cast pointers to integers and
+** integers to pointers.  The way you do this varies from one compiler
+** to the next, so we have developed the following set of #if statements
+** to generate appropriate macros for a wide range of compilers.
+**
+** The correct "ANSI" way to do this is to use the intptr_t type.
+** Unfortunately, that typedef is not available on all compilers, or
+** if it is available, it requires an #include of specific headers
+** that vary from one machine to the next.
+**
+** Ticket #3860:  The llvm-gcc-4.2 compiler from Apple chokes on
+** the ((void*)&((char*)0)[X]) construct.  But MSVC chokes on ((void*)(X)).
+** So we have to define the macros in different ways depending on the
+** compiler.
+*/
+#if defined(HAVE_STDINT_H)   /* Use this case if we have ANSI headers */
+# define SQLITE_INT_TO_PTR(X)  ((void*)(intptr_t)(X))
+# define SQLITE_PTR_TO_INT(X)  ((int)(intptr_t)(X))
+#elif defined(__PTRDIFF_TYPE__)  /* This case should work for GCC */
+# define SQLITE_INT_TO_PTR(X)  ((void*)(__PTRDIFF_TYPE__)(X))
+# define SQLITE_PTR_TO_INT(X)  ((int)(__PTRDIFF_TYPE__)(X))
+#elif !defined(__GNUC__)       /* Works for compilers other than LLVM */
+# define SQLITE_INT_TO_PTR(X)  ((void*)&((char*)0)[X])
+# define SQLITE_PTR_TO_INT(X)  ((int)(((char*)X)-(char*)0))
+#else                          /* Generates a warning - but it always works */
+# define SQLITE_INT_TO_PTR(X)  ((void*)(X))
+# define SQLITE_PTR_TO_INT(X)  ((int)(X))
+#endif
+
+/*
+** Macros to hint to the compiler that a function should or should not be
+** inlined.
+*/
+#if defined(__GNUC__)
+#  define SQLITE_NOINLINE  __attribute__((noinline))
+#  define SQLITE_INLINE    __attribute__((always_inline)) inline
+#elif defined(_MSC_VER) && _MSC_VER>=1310
+#  define SQLITE_NOINLINE  __declspec(noinline)
+#  define SQLITE_INLINE    __forceinline
+#else
+#  define SQLITE_NOINLINE
+#  define SQLITE_INLINE
+#endif
+#if defined(SQLITE_COVERAGE_TEST) || defined(__STRICT_ANSI__)
+# undef SQLITE_INLINE
+# define SQLITE_INLINE
+#endif
+
+/*
+** Make sure that the compiler intrinsics we desire are enabled when
+** compiling with an appropriate version of MSVC unless prevented by
+** the SQLITE_DISABLE_INTRINSIC define.
+*/
+#if !defined(SQLITE_DISABLE_INTRINSIC)
+#  if defined(_MSC_VER) && _MSC_VER>=1400
+#    if !defined(_WIN32_WCE)
+#      include <intrin.h>
+#      pragma intrinsic(_byteswap_ushort)
+#      pragma intrinsic(_byteswap_ulong)
+#      pragma intrinsic(_byteswap_uint64)
+#      pragma intrinsic(_ReadWriteBarrier)
+#    else
+#      include <cmnintrin.h>
+#    endif
+#  endif
+#endif
+
+/*
+** Enable SQLITE_USE_SEH by default on MSVC builds.  Only omit
+** SEH support if the -DSQLITE_OMIT_SEH option is given.
+*/
+#if defined(_MSC_VER) && !defined(SQLITE_OMIT_SEH)
+# define SQLITE_USE_SEH 1
+#else
+# undef SQLITE_USE_SEH
+#endif
+
+/*
+** Enable SQLITE_DIRECT_OVERFLOW_READ, unless the build explicitly
+** disables it using -DSQLITE_DIRECT_OVERFLOW_READ=0
+*/
+#if defined(SQLITE_DIRECT_OVERFLOW_READ) && SQLITE_DIRECT_OVERFLOW_READ+1==1
+  /* Disable if -DSQLITE_DIRECT_OVERFLOW_READ=0 */
+# undef SQLITE_DIRECT_OVERFLOW_READ
+#else
+  /* In all other cases, enable */
+# define SQLITE_DIRECT_OVERFLOW_READ 1
+#endif
+
+
+/*
+** The SQLITE_THREADSAFE macro must be defined as 0, 1, or 2.
+** 0 means mutexes are permanently disable and the library is never
+** threadsafe.  1 means the library is serialized which is the highest
+** level of threadsafety.  2 means the library is multithreaded - multiple
+** threads can use SQLite as long as no two threads try to use the same
+** database connection at the same time.
+**
+** Older versions of SQLite used an optional THREADSAFE macro.
+** We support that for legacy.
+**
+** To ensure that the correct value of "THREADSAFE" is reported when querying
+** for compile-time options at runtime (e.g. "PRAGMA compile_options"), this
+** logic is partially replicated in ctime.c. If it is updated here, it should
+** also be updated there.
+*/
+#if !defined(SQLITE_THREADSAFE)
+# if defined(THREADSAFE)
+#   define SQLITE_THREADSAFE THREADSAFE
+# else
+#   define SQLITE_THREADSAFE 1 /* IMP: R-07272-22309 */
+# endif
+#endif
+
+/*
+** Powersafe overwrite is on by default.  But can be turned off using
+** the -DSQLITE_POWERSAFE_OVERWRITE=0 command-line option.
+*/
+#ifndef SQLITE_POWERSAFE_OVERWRITE
+# define SQLITE_POWERSAFE_OVERWRITE 1
+#endif
+
+/*
+** EVIDENCE-OF: R-25715-37072 Memory allocation statistics are enabled by
+** default unless SQLite is compiled with SQLITE_DEFAULT_MEMSTATUS=0 in
+** which case memory allocation statistics are disabled by default.
+*/
+#if !defined(SQLITE_DEFAULT_MEMSTATUS)
+# define SQLITE_DEFAULT_MEMSTATUS 1
+#endif
+
+/*
+** Exactly one of the following macros must be defined in order to
+** specify which memory allocation subsystem to use.
+**
+**     SQLITE_SYSTEM_MALLOC          // Use normal system malloc()
+**     SQLITE_WIN32_MALLOC           // Use Win32 native heap API
+**     SQLITE_ZERO_MALLOC            // Use a stub allocator that always fails
+**     SQLITE_MEMDEBUG               // Debugging version of system malloc()
+**
+** On Windows, if the SQLITE_WIN32_MALLOC_VALIDATE macro is defined and the
+** assert() macro is enabled, each call into the Win32 native heap subsystem
+** will cause HeapValidate to be called.  If heap validation should fail, an
+** assertion will be triggered.
+**
+** If none of the above are defined, then set SQLITE_SYSTEM_MALLOC as
+** the default.
+*/
+#if defined(SQLITE_SYSTEM_MALLOC) \
+  + defined(SQLITE_WIN32_MALLOC) \
+  + defined(SQLITE_ZERO_MALLOC) \
+  + defined(SQLITE_MEMDEBUG)>1
+# error "Two or more of the following compile-time configuration options\
+ are defined but at most one is allowed:\
+ SQLITE_SYSTEM_MALLOC, SQLITE_WIN32_MALLOC, SQLITE_MEMDEBUG,\
+ SQLITE_ZERO_MALLOC"
+#endif
+#if defined(SQLITE_SYSTEM_MALLOC) \
+  + defined(SQLITE_WIN32_MALLOC) \
+  + defined(SQLITE_ZERO_MALLOC) \
+  + defined(SQLITE_MEMDEBUG)==0
+# define SQLITE_SYSTEM_MALLOC 1
+#endif
+
+/*
+** If SQLITE_MALLOC_SOFT_LIMIT is not zero, then try to keep the
+** sizes of memory allocations below this value where possible.
+*/
+#if !defined(SQLITE_MALLOC_SOFT_LIMIT)
+# define SQLITE_MALLOC_SOFT_LIMIT 1024
+#endif
+
+/*
+** We need to define _XOPEN_SOURCE as follows in order to enable
+** recursive mutexes on most Unix systems and fchmod() on OpenBSD.
+** But _XOPEN_SOURCE define causes problems for Mac OS X, so omit
+** it.
+*/
+#if !defined(_XOPEN_SOURCE) && !defined(__DARWIN__) && !defined(__APPLE__)
+#  define _XOPEN_SOURCE 600
+#endif
+
+/*
+** NDEBUG and SQLITE_DEBUG are opposites.  It should always be true that
+** defined(NDEBUG)==!defined(SQLITE_DEBUG).  If this is not currently true,
+** make it true by defining or undefining NDEBUG.
+**
+** Setting NDEBUG makes the code smaller and faster by disabling the
+** assert() statements in the code.  So we want the default action
+** to be for NDEBUG to be set and NDEBUG to be undefined only if SQLITE_DEBUG
+** is set.  Thus NDEBUG becomes an opt-in rather than an opt-out
+** feature.
+*/
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+#if defined(NDEBUG) && defined(SQLITE_DEBUG)
+# undef NDEBUG
+#endif
+
+/*
+** Enable SQLITE_ENABLE_EXPLAIN_COMMENTS if SQLITE_DEBUG is turned on.
+*/
+#if !defined(SQLITE_ENABLE_EXPLAIN_COMMENTS) && defined(SQLITE_DEBUG)
+# define SQLITE_ENABLE_EXPLAIN_COMMENTS 1
+#endif
+
+/*
+** The testcase() macro is used to aid in coverage testing.  When
+** doing coverage testing, the condition inside the argument to
+** testcase() must be evaluated both true and false in order to
+** get full branch coverage.  The testcase() macro is inserted
+** to help ensure adequate test coverage in places where simple
+** condition/decision coverage is inadequate.  For example, testcase()
+** can be used to make sure boundary values are tested.  For
+** bitmask tests, testcase() can be used to make sure each bit
+** is significant and used at least once.  On switch statements
+** where multiple cases go to the same block of code, testcase()
+** can insure that all cases are evaluated.
+*/
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_DEBUG)
+# ifndef SQLITE_AMALGAMATION
+    extern unsigned int sqlite3CoverageCounter;
+# endif
+# define testcase(X)  if( X ){ sqlite3CoverageCounter += (unsigned)__LINE__; }
+#else
+# define testcase(X)
+#endif
+
+/*
+** The TESTONLY macro is used to enclose variable declarations or
+** other bits of code that are needed to support the arguments
+** within testcase() and assert() macros.
+*/
+#if !defined(NDEBUG) || defined(SQLITE_COVERAGE_TEST)
+# define TESTONLY(X)  X
+#else
+# define TESTONLY(X)
+#endif
+
+/*
+** Sometimes we need a small amount of code such as a variable initialization
+** to setup for a later assert() statement.  We do not want this code to
+** appear when assert() is disabled.  The following macro is therefore
+** used to contain that setup code.  The "VVA" acronym stands for
+** "Verification, Validation, and Accreditation".  In other words, the
+** code within VVA_ONLY() will only run during verification processes.
+*/
+#ifndef NDEBUG
+# define VVA_ONLY(X)  X
+#else
+# define VVA_ONLY(X)
+#endif
+
+/*
+** Disable ALWAYS() and NEVER() (make them pass-throughs) for coverage
+** and mutation testing
+*/
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
+# define SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS  1
+#endif
+
+/*
+** The ALWAYS and NEVER macros surround boolean expressions which
+** are intended to always be true or false, respectively.  Such
+** expressions could be omitted from the code completely.  But they
+** are included in a few cases in order to enhance the resilience
+** of SQLite to unexpected behavior - to make the code "self-healing"
+** or "ductile" rather than being "brittle" and crashing at the first
+** hint of unplanned behavior.
+**
+** In other words, ALWAYS and NEVER are added for defensive code.
+**
+** When doing coverage testing ALWAYS and NEVER are hard-coded to
+** be true and false so that the unreachable code they specify will
+** not be counted as untested code.
+*/
+#if defined(SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS)
+# define ALWAYS(X)      (1)
+# define NEVER(X)       (0)
+#elif !defined(NDEBUG)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
+#else
+# define ALWAYS(X)      (X)
+# define NEVER(X)       (X)
+#endif
+
+/*
+** Some conditionals are optimizations only.  In other words, if the
+** conditionals are replaced with a constant 1 (true) or 0 (false) then
+** the correct answer is still obtained, though perhaps not as quickly.
+**
+** The following macros mark these optimizations conditionals.
+*/
+#if defined(SQLITE_MUTATION_TEST)
+# define OK_IF_ALWAYS_TRUE(X)  (1)
+# define OK_IF_ALWAYS_FALSE(X) (0)
+#else
+# define OK_IF_ALWAYS_TRUE(X)  (X)
+# define OK_IF_ALWAYS_FALSE(X) (X)
+#endif
+
+/*
+** Some malloc failures are only possible if SQLITE_TEST_REALLOC_STRESS is
+** defined.  We need to defend against those failures when testing with
+** SQLITE_TEST_REALLOC_STRESS, but we don't want the unreachable branches
+** during a normal build.  The following macro can be used to disable tests
+** that are always false except when SQLITE_TEST_REALLOC_STRESS is set.
+*/
+#if defined(SQLITE_TEST_REALLOC_STRESS)
+# define ONLY_IF_REALLOC_STRESS(X)  (X)
+#elif !defined(NDEBUG)
+# define ONLY_IF_REALLOC_STRESS(X)  ((X)?(assert(0),1):0)
+#else
+# define ONLY_IF_REALLOC_STRESS(X)  (0)
+#endif
+
+/*
+** Declarations used for tracing the operating system interfaces.
+*/
+#if defined(SQLITE_FORCE_OS_TRACE) || defined(SQLITE_TEST) || \
+    (defined(SQLITE_DEBUG) && SQLITE_OS_WIN)
+  extern int sqlite3OSTrace;
+# define OSTRACE(X)          if( sqlite3OSTrace ) sqlite3DebugPrintf X
+# define SQLITE_HAVE_OS_TRACE
+#else
+# define OSTRACE(X)
+# undef  SQLITE_HAVE_OS_TRACE
+#endif
+
+/*
+** Is the sqlite3ErrName() function needed in the build?  Currently,
+** it is needed by "mutex_w32.c" (when debugging), "os_win.c" (when
+** OSTRACE is enabled), and by several "test*.c" files (which are
+** compiled using SQLITE_TEST).
+*/
+#if defined(SQLITE_HAVE_OS_TRACE) || defined(SQLITE_TEST) || \
+    (defined(SQLITE_DEBUG) && SQLITE_OS_WIN)
+# define SQLITE_NEED_ERR_NAME
+#else
+# undef  SQLITE_NEED_ERR_NAME
+#endif
+
+/*
+** SQLITE_ENABLE_EXPLAIN_COMMENTS is incompatible with SQLITE_OMIT_EXPLAIN
+*/
+#ifdef SQLITE_OMIT_EXPLAIN
+# undef SQLITE_ENABLE_EXPLAIN_COMMENTS
+#endif
+
+/*
+** SQLITE_OMIT_VIRTUALTABLE implies SQLITE_OMIT_ALTERTABLE
+*/
+#if defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_ALTERTABLE)
+# define SQLITE_OMIT_ALTERTABLE
+#endif
+
+#define SQLITE_DIGIT_SEPARATOR '_'
+
+/*
+** Return true (non-zero) if the input is an integer that is too large
+** to fit in 32-bits.  This macro is used inside of various testcase()
+** macros to verify that we have tested SQLite for large-file support.
+*/
+#define IS_BIG_INT(X)  (((X)&~(i64)0xffffffff)!=0)
+
+/*
+** The macro unlikely() is a hint that surrounds a boolean
+** expression that is usually false.  Macro likely() surrounds
+** a boolean expression that is usually true.  These hints could,
+** in theory, be used by the compiler to generate better code, but
+** currently they are just comments for human readers.
+*/
+#define likely(X)    (X)
+#define unlikely(X)  (X)
+
+/************** Include hash.h in the middle of sqliteInt.h ******************/
+/************** Begin file hash.h ********************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for the generic hash-table implementation
+** used in SQLite.
+*/
+#ifndef SQLITE_HASH_H
+#define SQLITE_HASH_H
+
+/* Forward declarations of structures. */
+typedef struct Hash Hash;
+typedef struct HashElem HashElem;
+
+/* A complete hash table is an instance of the following structure.
+** The internals of this structure are intended to be opaque -- client
+** code should not attempt to access or modify the fields of this structure
+** directly.  Change this structure only by using the routines below.
+** However, some of the "procedures" and "functions" for modifying and
+** accessing this structure are really macros, so we can't really make
+** this structure opaque.
+**
+** All elements of the hash table are on a single doubly-linked list.
+** Hash.first points to the head of this list.
+**
+** There are Hash.htsize buckets.  Each bucket points to a spot in
+** the global doubly-linked list.  The contents of the bucket are the
+** element pointed to plus the next _ht.count-1 elements in the list.
+**
+** Hash.htsize and Hash.ht may be zero.  In that case lookup is done
+** by a linear search of the global list.  For small tables, the
+** Hash.ht table is never allocated because if there are few elements
+** in the table, it is faster to do a linear search than to manage
+** the hash table.
+*/
+struct Hash {
+  unsigned int htsize;      /* Number of buckets in the hash table */
+  unsigned int count;       /* Number of entries in this table */
+  HashElem *first;          /* The first element of the array */
+  struct _ht {              /* the hash table */
+    unsigned int count;        /* Number of entries with this hash */
+    HashElem *chain;           /* Pointer to first entry with this hash */
+  } *ht;
+};
+
+/* Each element in the hash table is an instance of the following
+** structure.  All elements are stored on a single doubly-linked list.
+**
+** Again, this structure is intended to be opaque, but it can't really
+** be opaque because it is used by macros.
+*/
+struct HashElem {
+  HashElem *next, *prev;       /* Next and previous elements in the table */
+  void *data;                  /* Data associated with this element */
+  const char *pKey;            /* Key associated with this element */
+};
+
+/*
+** Access routines.  To delete, insert a NULL pointer.
+*/
+SQLITE_PRIVATE void sqlite3HashInit(Hash*);
+SQLITE_PRIVATE void *sqlite3HashInsert(Hash*, const char *pKey, void *pData);
+SQLITE_PRIVATE void *sqlite3HashFind(const Hash*, const char *pKey);
+SQLITE_PRIVATE void sqlite3HashClear(Hash*);
+
+/*
+** Macros for looping over all elements of a hash table.  The idiom is
+** like this:
+**
+**   Hash h;
+**   HashElem *p;
+**   ...
+**   for(p=sqliteHashFirst(&h); p; p=sqliteHashNext(p)){
+**     SomeStructure *pData = sqliteHashData(p);
+**     // do something with pData
+**   }
+*/
+#define sqliteHashFirst(H)  ((H)->first)
+#define sqliteHashNext(E)   ((E)->next)
+#define sqliteHashData(E)   ((E)->data)
+/* #define sqliteHashKey(E)    ((E)->pKey) // NOT USED */
+/* #define sqliteHashKeysize(E) ((E)->nKey)  // NOT USED */
+
+/*
+** Number of entries in a hash table
+*/
+#define sqliteHashCount(H)  ((H)->count)
+
+#endif /* SQLITE_HASH_H */
+
+/************** End of hash.h ************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include parse.h in the middle of sqliteInt.h *****************/
+/************** Begin file parse.h *******************************************/
+#define TK_SEMI                             1
+#define TK_EXPLAIN                          2
+#define TK_QUERY                            3
+#define TK_PLAN                             4
+#define TK_BEGIN                            5
+#define TK_TRANSACTION                      6
+#define TK_DEFERRED                         7
+#define TK_IMMEDIATE                        8
+#define TK_EXCLUSIVE                        9
+#define TK_COMMIT                          10
+#define TK_END                             11
+#define TK_ROLLBACK                        12
+#define TK_SAVEPOINT                       13
+#define TK_RELEASE                         14
+#define TK_TO                              15
+#define TK_TABLE                           16
+#define TK_CREATE                          17
+#define TK_IF                              18
+#define TK_NOT                             19
+#define TK_EXISTS                          20
+#define TK_TEMP                            21
+#define TK_LP                              22
+#define TK_RP                              23
+#define TK_AS                              24
+#define TK_COMMA                           25
+#define TK_WITHOUT                         26
+#define TK_ABORT                           27
+#define TK_ACTION                          28
+#define TK_AFTER                           29
+#define TK_ANALYZE                         30
+#define TK_ASC                             31
+#define TK_ATTACH                          32
+#define TK_BEFORE                          33
+#define TK_BY                              34
+#define TK_CASCADE                         35
+#define TK_CAST                            36
+#define TK_CONFLICT                        37
+#define TK_DATABASE                        38
+#define TK_DESC                            39
+#define TK_DETACH                          40
+#define TK_EACH                            41
+#define TK_FAIL                            42
+#define TK_OR                              43
+#define TK_AND                             44
+#define TK_IS                              45
+#define TK_ISNOT                           46
+#define TK_MATCH                           47
+#define TK_LIKE_KW                         48
+#define TK_BETWEEN                         49
+#define TK_IN                              50
+#define TK_ISNULL                          51
+#define TK_NOTNULL                         52
+#define TK_NE                              53
+#define TK_EQ                              54
+#define TK_GT                              55
+#define TK_LE                              56
+#define TK_LT                              57
+#define TK_GE                              58
+#define TK_ESCAPE                          59
+#define TK_ID                              60
+#define TK_COLUMNKW                        61
+#define TK_DO                              62
+#define TK_FOR                             63
+#define TK_IGNORE                          64
+#define TK_INITIALLY                       65
+#define TK_INSTEAD                         66
+#define TK_NO                              67
+#define TK_KEY                             68
+#define TK_OF                              69
+#define TK_OFFSET                          70
+#define TK_PRAGMA                          71
+#define TK_RAISE                           72
+#define TK_RECURSIVE                       73
+#define TK_REPLACE                         74
+#define TK_RESTRICT                        75
+#define TK_ROW                             76
+#define TK_ROWS                            77
+#define TK_TRIGGER                         78
+#define TK_VACUUM                          79
+#define TK_VIEW                            80
+#define TK_VIRTUAL                         81
+#define TK_WITH                            82
+#define TK_NULLS                           83
+#define TK_FIRST                           84
+#define TK_LAST                            85
+#define TK_CURRENT                         86
+#define TK_FOLLOWING                       87
+#define TK_PARTITION                       88
+#define TK_PRECEDING                       89
+#define TK_RANGE                           90
+#define TK_UNBOUNDED                       91
+#define TK_EXCLUDE                         92
+#define TK_GROUPS                          93
+#define TK_OTHERS                          94
+#define TK_TIES                            95
+#define TK_GENERATED                       96
+#define TK_ALWAYS                          97
+#define TK_MATERIALIZED                    98
+#define TK_REINDEX                         99
+#define TK_RENAME                         100
+#define TK_CTIME_KW                       101
+#define TK_ANY                            102
+#define TK_BITAND                         103
+#define TK_BITOR                          104
+#define TK_LSHIFT                         105
+#define TK_RSHIFT                         106
+#define TK_PLUS                           107
+#define TK_MINUS                          108
+#define TK_STAR                           109
+#define TK_SLASH                          110
+#define TK_REM                            111
+#define TK_CONCAT                         112
+#define TK_PTR                            113
+#define TK_COLLATE                        114
+#define TK_BITNOT                         115
+#define TK_ON                             116
+#define TK_INDEXED                        117
+#define TK_STRING                         118
+#define TK_JOIN_KW                        119
+#define TK_CONSTRAINT                     120
+#define TK_DEFAULT                        121
+#define TK_NULL                           122
+#define TK_PRIMARY                        123
+#define TK_UNIQUE                         124
+#define TK_CHECK                          125
+#define TK_REFERENCES                     126
+#define TK_AUTOINCR                       127
+#define TK_INSERT                         128
+#define TK_DELETE                         129
+#define TK_UPDATE                         130
+#define TK_SET                            131
+#define TK_DEFERRABLE                     132
+#define TK_FOREIGN                        133
+#define TK_DROP                           134
+#define TK_UNION                          135
+#define TK_ALL                            136
+#define TK_EXCEPT                         137
+#define TK_INTERSECT                      138
+#define TK_SELECT                         139
+#define TK_VALUES                         140
+#define TK_DISTINCT                       141
+#define TK_DOT                            142
+#define TK_FROM                           143
+#define TK_JOIN                           144
+#define TK_USING                          145
+#define TK_ORDER                          146
+#define TK_GROUP                          147
+#define TK_HAVING                         148
+#define TK_LIMIT                          149
+#define TK_WHERE                          150
+#define TK_RETURNING                      151
+#define TK_INTO                           152
+#define TK_NOTHING                        153
+#define TK_FLOAT                          154
+#define TK_BLOB                           155
+#define TK_INTEGER                        156
+#define TK_VARIABLE                       157
+#define TK_CASE                           158
+#define TK_WHEN                           159
+#define TK_THEN                           160
+#define TK_ELSE                           161
+#define TK_INDEX                          162
+#define TK_ALTER                          163
+#define TK_ADD                            164
+#define TK_WINDOW                         165
+#define TK_OVER                           166
+#define TK_FILTER                         167
+#define TK_COLUMN                         168
+#define TK_AGG_FUNCTION                   169
+#define TK_AGG_COLUMN                     170
+#define TK_TRUEFALSE                      171
+#define TK_FUNCTION                       172
+#define TK_UPLUS                          173
+#define TK_UMINUS                         174
+#define TK_TRUTH                          175
+#define TK_REGISTER                       176
+#define TK_VECTOR                         177
+#define TK_SELECT_COLUMN                  178
+#define TK_IF_NULL_ROW                    179
+#define TK_ASTERISK                       180
+#define TK_SPAN                           181
+#define TK_ERROR                          182
+#define TK_QNUMBER                        183
+#define TK_SPACE                          184
+#define TK_COMMENT                        185
+#define TK_ILLEGAL                        186
+
+/************** End of parse.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <stddef.h>
+#include <ctype.h>
+
+/*
+** Use a macro to replace memcpy() if compiled with SQLITE_INLINE_MEMCPY.
+** This allows better measurements of where memcpy() is used when running
+** cachegrind.  But this macro version of memcpy() is very slow so it
+** should not be used in production.  This is a performance measurement
+** hack only.
+*/
+#ifdef SQLITE_INLINE_MEMCPY
+# define memcpy(D,S,N) {char*xxd=(char*)(D);const char*xxs=(const char*)(S);\
+                        int xxn=(N);while(xxn-->0)*(xxd++)=*(xxs++);}
+#endif
+
+/*
+** If compiling for a processor that lacks floating point support,
+** substitute integer for floating-point
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define double sqlite_int64
+# define float sqlite_int64
+# define fabs(X) ((X)<0?-(X):(X))
+# define sqlite3IsOverflow(X) 0
+# ifndef SQLITE_BIG_DBL
+#   define SQLITE_BIG_DBL (((sqlite3_int64)1)<<50)
+# endif
+# define SQLITE_OMIT_DATETIME_FUNCS 1
+# define SQLITE_OMIT_TRACE 1
+# undef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+# undef SQLITE_HAVE_ISNAN
+#endif
+#ifndef SQLITE_BIG_DBL
+# define SQLITE_BIG_DBL (1e99)
+#endif
+
+/*
+** OMIT_TEMPDB is set to 1 if SQLITE_OMIT_TEMPDB is defined, or 0
+** afterward. Having this macro allows us to cause the C compiler
+** to omit code used by TEMP tables without messy #ifndef statements.
+*/
+#ifdef SQLITE_OMIT_TEMPDB
+#define OMIT_TEMPDB 1
+#else
+#define OMIT_TEMPDB 0
+#endif
+
+/*
+** The "file format" number is an integer that is incremented whenever
+** the VDBE-level file format changes.  The following macros define the
+** the default file format for new databases and the maximum file format
+** that the library can read.
+*/
+#define SQLITE_MAX_FILE_FORMAT 4
+#ifndef SQLITE_DEFAULT_FILE_FORMAT
+# define SQLITE_DEFAULT_FILE_FORMAT 4
+#endif
+
+/*
+** Determine whether triggers are recursive by default.  This can be
+** changed at run-time using a pragma.
+*/
+#ifndef SQLITE_DEFAULT_RECURSIVE_TRIGGERS
+# define SQLITE_DEFAULT_RECURSIVE_TRIGGERS 0
+#endif
+
+/*
+** Provide a default value for SQLITE_TEMP_STORE in case it is not specified
+** on the command-line
+*/
+#ifndef SQLITE_TEMP_STORE
+# define SQLITE_TEMP_STORE 1
+#endif
+
+/*
+** If no value has been provided for SQLITE_MAX_WORKER_THREADS, or if
+** SQLITE_TEMP_STORE is set to 3 (never use temporary files), set it
+** to zero.
+*/
+#if SQLITE_TEMP_STORE==3 || SQLITE_THREADSAFE==0
+# undef SQLITE_MAX_WORKER_THREADS
+# define SQLITE_MAX_WORKER_THREADS 0
+#endif
+#ifndef SQLITE_MAX_WORKER_THREADS
+# define SQLITE_MAX_WORKER_THREADS 8
+#endif
+#ifndef SQLITE_DEFAULT_WORKER_THREADS
+# define SQLITE_DEFAULT_WORKER_THREADS 0
+#endif
+#if SQLITE_DEFAULT_WORKER_THREADS>SQLITE_MAX_WORKER_THREADS
+# undef SQLITE_MAX_WORKER_THREADS
+# define SQLITE_MAX_WORKER_THREADS SQLITE_DEFAULT_WORKER_THREADS
+#endif
+
+/*
+** The default initial allocation for the pagecache when using separate
+** pagecaches for each database connection.  A positive number is the
+** number of pages.  A negative number N translations means that a buffer
+** of -1024*N bytes is allocated and used for as many pages as it will hold.
+**
+** The default value of "20" was chosen to minimize the run-time of the
+** speedtest1 test program with options: --shrink-memory --reprepare
+*/
+#ifndef SQLITE_DEFAULT_PCACHE_INITSZ
+# define SQLITE_DEFAULT_PCACHE_INITSZ 20
+#endif
+
+/*
+** Default value for the SQLITE_CONFIG_SORTERREF_SIZE option.
+*/
+#ifndef SQLITE_DEFAULT_SORTERREF_SIZE
+# define SQLITE_DEFAULT_SORTERREF_SIZE 0x7fffffff
+#endif
+
+/*
+** The compile-time options SQLITE_MMAP_READWRITE and
+** SQLITE_ENABLE_BATCH_ATOMIC_WRITE are not compatible with one another.
+** You must choose one or the other (or neither) but not both.
+*/
+#if defined(SQLITE_MMAP_READWRITE) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+#error Cannot use both SQLITE_MMAP_READWRITE and SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+#endif
+
+/*
+** GCC does not define the offsetof() macro so we'll have to do it
+** ourselves.
+*/
+#ifndef offsetof
+#define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))
+#endif
+
+/*
+** Macros to compute minimum and maximum of two numbers.
+*/
+#ifndef MIN
+# define MIN(A,B) ((A)<(B)?(A):(B))
+#endif
+#ifndef MAX
+# define MAX(A,B) ((A)>(B)?(A):(B))
+#endif
+
+/*
+** Swap two objects of type TYPE.
+*/
+#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
+
+/*
+** Check to see if this machine uses EBCDIC.  (Yes, believe it or
+** not, there are still machines out there that use EBCDIC.)
+*/
+#if 'A' == '\301'
+# define SQLITE_EBCDIC 1
+#else
+# define SQLITE_ASCII 1
+#endif
+
+/*
+** Integers of known sizes.  These typedefs might change for architectures
+** where the sizes very.  Preprocessor macros are available so that the
+** types can be conveniently redefined at compile-type.  Like this:
+**
+**         cc '-DUINTPTR_TYPE=long long int' ...
+*/
+#ifndef UINT32_TYPE
+# ifdef HAVE_UINT32_T
+#  define UINT32_TYPE uint32_t
+# else
+#  define UINT32_TYPE unsigned int
+# endif
+#endif
+#ifndef UINT16_TYPE
+# ifdef HAVE_UINT16_T
+#  define UINT16_TYPE uint16_t
+# else
+#  define UINT16_TYPE unsigned short int
+# endif
+#endif
+#ifndef INT16_TYPE
+# ifdef HAVE_INT16_T
+#  define INT16_TYPE int16_t
+# else
+#  define INT16_TYPE short int
+# endif
+#endif
+#ifndef UINT8_TYPE
+# ifdef HAVE_UINT8_T
+#  define UINT8_TYPE uint8_t
+# else
+#  define UINT8_TYPE unsigned char
+# endif
+#endif
+#ifndef INT8_TYPE
+# ifdef HAVE_INT8_T
+#  define INT8_TYPE int8_t
+# else
+#  define INT8_TYPE signed char
+# endif
+#endif
+typedef sqlite_int64 i64;          /* 8-byte signed integer */
+typedef sqlite_uint64 u64;         /* 8-byte unsigned integer */
+typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
+typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
+typedef INT16_TYPE i16;            /* 2-byte signed integer */
+typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
+typedef INT8_TYPE i8;              /* 1-byte signed integer */
+
+/*
+** SQLITE_MAX_U32 is a u64 constant that is the maximum u64 value
+** that can be stored in a u32 without loss of data.  The value
+** is 0x00000000ffffffff.  But because of quirks of some compilers, we
+** have to specify the value in the less intuitive manner shown:
+*/
+#define SQLITE_MAX_U32  ((((u64)1)<<32)-1)
+
+/*
+** The datatype used to store estimates of the number of rows in a
+** table or index.
+*/
+typedef u64 tRowcnt;
+
+/*
+** Estimated quantities used for query planning are stored as 16-bit
+** logarithms.  For quantity X, the value stored is 10*log2(X).  This
+** gives a possible range of values of approximately 1.0e986 to 1e-986.
+** But the allowed values are "grainy".  Not every value is representable.
+** For example, quantities 16 and 17 are both represented by a LogEst
+** of 40.  However, since LogEst quantities are suppose to be estimates,
+** not exact values, this imprecision is not a problem.
+**
+** "LogEst" is short for "Logarithmic Estimate".
+**
+** Examples:
+**      1 -> 0              20 -> 43          10000 -> 132
+**      2 -> 10             25 -> 46          25000 -> 146
+**      3 -> 16            100 -> 66        1000000 -> 199
+**      4 -> 20           1000 -> 99        1048576 -> 200
+**     10 -> 33           1024 -> 100    4294967296 -> 320
+**
+** The LogEst can be negative to indicate fractional values.
+** Examples:
+**
+**    0.5 -> -10           0.1 -> -33        0.0625 -> -40
+*/
+typedef INT16_TYPE LogEst;
+#define LOGEST_MIN (-32768)
+#define LOGEST_MAX (32767)
+
+/*
+** Set the SQLITE_PTRSIZE macro to the number of bytes in a pointer
+*/
+#ifndef SQLITE_PTRSIZE
+# if defined(__SIZEOF_POINTER__)
+#   define SQLITE_PTRSIZE __SIZEOF_POINTER__
+# elif defined(i386)     || defined(__i386__)   || defined(_M_IX86) ||    \
+       defined(_M_ARM)   || defined(__arm__)    || defined(__x86)   ||    \
+      (defined(__APPLE__) && defined(__ppc__)) ||                         \
+      (defined(__TOS_AIX__) && !defined(__64BIT__))
+#   define SQLITE_PTRSIZE 4
+# else
+#   define SQLITE_PTRSIZE 8
+# endif
+#endif
+
+/* The uptr type is an unsigned integer large enough to hold a pointer
+*/
+#if defined(HAVE_STDINT_H)
+  typedef uintptr_t uptr;
+#elif SQLITE_PTRSIZE==4
+  typedef u32 uptr;
+#else
+  typedef u64 uptr;
+#endif
+
+/*
+** The SQLITE_WITHIN(P,S,E) macro checks to see if pointer P points to
+** something between S (inclusive) and E (exclusive).
+**
+** In other words, S is a buffer and E is a pointer to the first byte after
+** the end of buffer S.  This macro returns true if P points to something
+** contained within the buffer S.
+*/
+#define SQLITE_WITHIN(P,S,E)   (((uptr)(P)>=(uptr)(S))&&((uptr)(P)<(uptr)(E)))
+
+/*
+** P is one byte past the end of a large buffer. Return true if a span of bytes
+** between S..E crosses the end of that buffer.  In other words, return true
+** if the sub-buffer S..E-1 overflows the buffer whose last byte is P-1.
+**
+** S is the start of the span.  E is one byte past the end of end of span.
+**
+**                        P
+**     |-----------------|                FALSE
+**               |-------|
+**               S        E
+**
+**                        P
+**     |-----------------|
+**                    |-------|           TRUE
+**                    S        E
+**
+**                        P
+**     |-----------------|
+**                        |-------|       FALSE
+**                        S        E
+*/
+#define SQLITE_OVERFLOW(P,S,E) (((uptr)(S)<(uptr)(P))&&((uptr)(E)>(uptr)(P)))
+
+/*
+** Macros to determine whether the machine is big or little endian,
+** and whether or not that determination is run-time or compile-time.
+**
+** For best performance, an attempt is made to guess at the byte-order
+** using C-preprocessor macros.  If that is unsuccessful, or if
+** -DSQLITE_BYTEORDER=0 is set, then byte-order is determined
+** at run-time.
+**
+** If you are building SQLite on some obscure platform for which the
+** following ifdef magic does not work, you can always include either:
+**
+**    -DSQLITE_BYTEORDER=1234
+**
+** or
+**
+**    -DSQLITE_BYTEORDER=4321
+**
+** to cause the build to work for little-endian or big-endian processors,
+** respectively.
+*/
+#ifndef SQLITE_BYTEORDER  /* Replicate changes at tag-20230904a */
+# if defined(__BYTE_ORDER__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
+#   define SQLITE_BYTEORDER 4321
+# elif defined(__BYTE_ORDER__) && __BYTE_ORDER__==__ORDER_LITTLE_ENDIAN__
+#   define SQLITE_BYTEORDER 1234
+# elif defined(__BIG_ENDIAN__) && __BIG_ENDIAN__==1
+#   define SQLITE_BYTEORDER 4321
+# elif defined(i386)    || defined(__i386__)      || defined(_M_IX86) ||    \
+     defined(__x86_64)  || defined(__x86_64__)    || defined(_M_X64)  ||    \
+     defined(_M_AMD64)  || defined(_M_ARM)        || defined(__x86)   ||    \
+     defined(__ARMEL__) || defined(__AARCH64EL__) || defined(_M_ARM64)
+#   define SQLITE_BYTEORDER 1234
+# elif defined(sparc)   || defined(__ARMEB__)     || defined(__AARCH64EB__)
+#   define SQLITE_BYTEORDER 4321
+# else
+#   define SQLITE_BYTEORDER 0
+# endif
+#endif
+#if SQLITE_BYTEORDER==4321
+# define SQLITE_BIGENDIAN    1
+# define SQLITE_LITTLEENDIAN 0
+# define SQLITE_UTF16NATIVE  SQLITE_UTF16BE
+#elif SQLITE_BYTEORDER==1234
+# define SQLITE_BIGENDIAN    0
+# define SQLITE_LITTLEENDIAN 1
+# define SQLITE_UTF16NATIVE  SQLITE_UTF16LE
+#else
+# ifdef SQLITE_AMALGAMATION
+  const int sqlite3one = 1;
+# else
+  extern const int sqlite3one;
+# endif
+# define SQLITE_BIGENDIAN    (*(char *)(&sqlite3one)==0)
+# define SQLITE_LITTLEENDIAN (*(char *)(&sqlite3one)==1)
+# define SQLITE_UTF16NATIVE  (SQLITE_BIGENDIAN?SQLITE_UTF16BE:SQLITE_UTF16LE)
+#endif
+
+/*
+** Constants for the largest and smallest possible 64-bit signed integers.
+** These macros are designed to work correctly on both 32-bit and 64-bit
+** compilers.
+*/
+#define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
+#define LARGEST_UINT64 (0xffffffff|(((u64)0xffffffff)<<32))
+#define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
+
+/*
+** Round up a number to the next larger multiple of 8.  This is used
+** to force 8-byte alignment on 64-bit architectures.
+**
+** ROUND8() always does the rounding, for any argument.
+**
+** ROUND8P() assumes that the argument is already an integer number of
+** pointers in size, and so it is a no-op on systems where the pointer
+** size is 8.
+*/
+#define ROUND8(x)     (((x)+7)&~7)
+#if SQLITE_PTRSIZE==8
+# define ROUND8P(x)   (x)
+#else
+# define ROUND8P(x)   (((x)+7)&~7)
+#endif
+
+/*
+** Round down to the nearest multiple of 8
+*/
+#define ROUNDDOWN8(x) ((x)&~7)
+
+/*
+** Assert that the pointer X is aligned to an 8-byte boundary.  This
+** macro is used only within assert() to verify that the code gets
+** all alignment restrictions correct.
+**
+** Except, if SQLITE_4_BYTE_ALIGNED_MALLOC is defined, then the
+** underlying malloc() implementation might return us 4-byte aligned
+** pointers.  In that case, only verify 4-byte alignment.
+*/
+#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&3)==0)
+#else
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&7)==0)
+#endif
+
+/*
+** Disable MMAP on platforms where it is known to not work
+*/
+#if defined(__OpenBSD__) || defined(__QNXNTO__)
+# undef SQLITE_MAX_MMAP_SIZE
+# define SQLITE_MAX_MMAP_SIZE 0
+#endif
+
+/*
+** Default maximum size of memory used by memory-mapped I/O in the VFS
+*/
+#ifdef __APPLE__
+# include <TargetConditionals.h>
+#endif
+#ifndef SQLITE_MAX_MMAP_SIZE
+# if defined(__linux__) \
+  || defined(_WIN32) \
+  || (defined(__APPLE__) && defined(__MACH__)) \
+  || defined(__sun) \
+  || defined(__FreeBSD__) \
+  || defined(__DragonFly__)
+#   define SQLITE_MAX_MMAP_SIZE 0x7fff0000  /* 2147418112 */
+# else
+#   define SQLITE_MAX_MMAP_SIZE 0
+# endif
+#endif
+
+/*
+** The default MMAP_SIZE is zero on all platforms.  Or, even if a larger
+** default MMAP_SIZE is specified at compile-time, make sure that it does
+** not exceed the maximum mmap size.
+*/
+#ifndef SQLITE_DEFAULT_MMAP_SIZE
+# define SQLITE_DEFAULT_MMAP_SIZE 0
+#endif
+#if SQLITE_DEFAULT_MMAP_SIZE>SQLITE_MAX_MMAP_SIZE
+# undef SQLITE_DEFAULT_MMAP_SIZE
+# define SQLITE_DEFAULT_MMAP_SIZE SQLITE_MAX_MMAP_SIZE
+#endif
+
+/*
+** TREETRACE_ENABLED will be either 1 or 0 depending on whether or not
+** the Abstract Syntax Tree tracing logic is turned on.
+*/
+#if !defined(SQLITE_AMALGAMATION)
+SQLITE_PRIVATE u32 sqlite3TreeTrace;
+#endif
+#if defined(SQLITE_DEBUG) \
+    && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_SELECTTRACE) \
+                             || defined(SQLITE_ENABLE_TREETRACE))
+# define TREETRACE_ENABLED 1
+# define TREETRACE(K,P,S,X)  \
+  if(sqlite3TreeTrace&(K))   \
+    sqlite3DebugPrintf("%u/%d/%p: ",(S)->selId,(P)->addrExplain,(S)),\
+    sqlite3DebugPrintf X
+#else
+# define TREETRACE(K,P,S,X)
+# define TREETRACE_ENABLED 0
+#endif
+
+/* TREETRACE flag meanings:
+**
+**   0x00000001     Beginning and end of SELECT processing
+**   0x00000002     WHERE clause processing
+**   0x00000004     Query flattener
+**   0x00000008     Result-set wildcard expansion
+**   0x00000010     Query name resolution
+**   0x00000020     Aggregate analysis
+**   0x00000040     Window functions
+**   0x00000080     Generated column names
+**   0x00000100     Move HAVING terms into WHERE
+**   0x00000200     Count-of-view optimization
+**   0x00000400     Compound SELECT processing
+**   0x00000800     Drop superfluous ORDER BY
+**   0x00001000     LEFT JOIN simplifies to JOIN
+**   0x00002000     Constant propagation
+**   0x00004000     Push-down optimization
+**   0x00008000     After all FROM-clause analysis
+**   0x00010000     Beginning of DELETE/INSERT/UPDATE processing
+**   0x00020000     Transform DISTINCT into GROUP BY
+**   0x00040000     SELECT tree dump after all code has been generated
+**   0x00080000     NOT NULL strength reduction
+*/
+
+/*
+** Macros for "wheretrace"
+*/
+SQLITE_PRIVATE u32 sqlite3WhereTrace;
+#if defined(SQLITE_DEBUG) \
+    && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_WHERETRACE))
+# define WHERETRACE(K,X)  if(sqlite3WhereTrace&(K)) sqlite3DebugPrintf X
+# define WHERETRACE_ENABLED 1
+#else
+# define WHERETRACE(K,X)
+#endif
+
+/*
+** Bits for the sqlite3WhereTrace mask:
+**
+** (---any--)   Top-level block structure
+** 0x-------F   High-level debug messages
+** 0x----FFF-   More detail
+** 0xFFFF----   Low-level debug messages
+**
+** 0x00000001   Code generation
+** 0x00000002   Solver (Use 0x40000 for less detail)
+** 0x00000004   Solver costs
+** 0x00000008   WhereLoop inserts
+**
+** 0x00000010   Display sqlite3_index_info xBestIndex calls
+** 0x00000020   Range an equality scan metrics
+** 0x00000040   IN operator decisions
+** 0x00000080   WhereLoop cost adjustments
+** 0x00000100
+** 0x00000200   Covering index decisions
+** 0x00000400   OR optimization
+** 0x00000800   Index scanner
+** 0x00001000   More details associated with code generation
+** 0x00002000
+** 0x00004000   Show all WHERE terms at key points
+** 0x00008000   Show the full SELECT statement at key places
+**
+** 0x00010000   Show more detail when printing WHERE terms
+** 0x00020000   Show WHERE terms returned from whereScanNext()
+** 0x00040000   Solver overview messages
+** 0x00080000   Star-query heuristic
+*/
+
+
+/*
+** An instance of the following structure is used to store the busy-handler
+** callback for a given sqlite handle.
+**
+** The sqlite.busyHandler member of the sqlite struct contains the busy
+** callback for the database handle. Each pager opened via the sqlite
+** handle is passed a pointer to sqlite.busyHandler. The busy-handler
+** callback is currently invoked only from within pager.c.
+*/
+typedef struct BusyHandler BusyHandler;
+struct BusyHandler {
+  int (*xBusyHandler)(void *,int);  /* The busy callback */
+  void *pBusyArg;                   /* First arg to busy callback */
+  int nBusy;                        /* Incremented with each busy call */
+};
+
+/*
+** Name of table that holds the database schema.
+**
+** The PREFERRED names are used wherever possible.  But LEGACY is also
+** used for backwards compatibility.
+**
+**  1.  Queries can use either the PREFERRED or the LEGACY names
+**  2.  The sqlite3_set_authorizer() callback uses the LEGACY name
+**  3.  The PRAGMA table_list statement uses the PREFERRED name
+**
+** The LEGACY names are stored in the internal symbol hash table
+** in support of (2).  Names are translated using sqlite3PreferredTableName()
+** for (3).  The sqlite3FindTable() function takes care of translating
+** names for (1).
+**
+** Note that "sqlite_temp_schema" can also be called "temp.sqlite_schema".
+*/
+#define LEGACY_SCHEMA_TABLE          "sqlite_master"
+#define LEGACY_TEMP_SCHEMA_TABLE     "sqlite_temp_master"
+#define PREFERRED_SCHEMA_TABLE       "sqlite_schema"
+#define PREFERRED_TEMP_SCHEMA_TABLE  "sqlite_temp_schema"
+
+
+/*
+** The root-page of the schema table.
+*/
+#define SCHEMA_ROOT    1
+
+/*
+** The name of the schema table.  The name is different for TEMP.
+*/
+#define SCHEMA_TABLE(x) \
+    ((!OMIT_TEMPDB)&&(x==1)?LEGACY_TEMP_SCHEMA_TABLE:LEGACY_SCHEMA_TABLE)
+
+/*
+** A convenience macro that returns the number of elements in
+** an array.
+*/
+#define ArraySize(X)    ((int)(sizeof(X)/sizeof(X[0])))
+
+/*
+** Determine if the argument is a power of two
+*/
+#define IsPowerOfTwo(X) (((X)&((X)-1))==0)
+
+/*
+** The following value as a destructor means to use sqlite3DbFree().
+** The sqlite3DbFree() routine requires two parameters instead of the
+** one parameter that destructors normally want.  So we have to introduce
+** this magic value that the code knows to handle differently.  Any
+** pointer will work here as long as it is distinct from SQLITE_STATIC
+** and SQLITE_TRANSIENT.
+*/
+#define SQLITE_DYNAMIC   ((sqlite3_destructor_type)sqlite3OomClear)
+
+/*
+** When SQLITE_OMIT_WSD is defined, it means that the target platform does
+** not support Writable Static Data (WSD) such as global and static variables.
+** All variables must either be on the stack or dynamically allocated from
+** the heap.  When WSD is unsupported, the variable declarations scattered
+** throughout the SQLite code must become constants instead.  The SQLITE_WSD
+** macro is used for this purpose.  And instead of referencing the variable
+** directly, we use its constant as a key to lookup the run-time allocated
+** buffer that holds real variable.  The constant is also the initializer
+** for the run-time allocated buffer.
+**
+** In the usual case where WSD is supported, the SQLITE_WSD and GLOBAL
+** macros become no-ops and have zero performance impact.
+*/
+#ifdef SQLITE_OMIT_WSD
+  #define SQLITE_WSD const
+  #define GLOBAL(t,v) (*(t*)sqlite3_wsd_find((void*)&(v), sizeof(v)))
+  #define sqlite3GlobalConfig GLOBAL(struct Sqlite3Config, sqlite3Config)
+SQLITE_API int sqlite3_wsd_init(int N, int J);
+SQLITE_API void *sqlite3_wsd_find(void *K, int L);
+#else
+  #define SQLITE_WSD
+  #define GLOBAL(t,v) v
+  #define sqlite3GlobalConfig sqlite3Config
+#endif
+
+/*
+** The following macros are used to suppress compiler warnings and to
+** make it clear to human readers when a function parameter is deliberately
+** left unused within the body of a function. This usually happens when
+** a function is called via a function pointer. For example the
+** implementation of an SQL aggregate step callback may not use the
+** parameter indicating the number of arguments passed to the aggregate,
+** if it knows that this is enforced elsewhere.
+**
+** When a function parameter is not used at all within the body of a function,
+** it is generally named "NotUsed" or "NotUsed2" to make things even clearer.
+** However, these macros may also be used to suppress warnings related to
+** parameters that may or may not be used depending on compilation options.
+** For example those parameters only used in assert() statements. In these
+** cases the parameters are named as per the usual conventions.
+*/
+#define UNUSED_PARAMETER(x) (void)(x)
+#define UNUSED_PARAMETER2(x,y) UNUSED_PARAMETER(x),UNUSED_PARAMETER(y)
+
+/*
+** Forward references to structures
+*/
+typedef struct AggInfo AggInfo;
+typedef struct AuthContext AuthContext;
+typedef struct AutoincInfo AutoincInfo;
+typedef struct Bitvec Bitvec;
+typedef struct CollSeq CollSeq;
+typedef struct Column Column;
+typedef struct Cte Cte;
+typedef struct CteUse CteUse;
+typedef struct Db Db;
+typedef struct DbClientData DbClientData;
+typedef struct DbFixer DbFixer;
+typedef struct Schema Schema;
+typedef struct Expr Expr;
+typedef struct ExprList ExprList;
+typedef struct FKey FKey;
+typedef struct FpDecode FpDecode;
+typedef struct FuncDestructor FuncDestructor;
+typedef struct FuncDef FuncDef;
+typedef struct FuncDefHash FuncDefHash;
+typedef struct IdList IdList;
+typedef struct Index Index;
+typedef struct IndexedExpr IndexedExpr;
+typedef struct IndexSample IndexSample;
+typedef struct KeyClass KeyClass;
+typedef struct KeyInfo KeyInfo;
+typedef struct Lookaside Lookaside;
+typedef struct LookasideSlot LookasideSlot;
+typedef struct Module Module;
+typedef struct NameContext NameContext;
+typedef struct OnOrUsing OnOrUsing;
+typedef struct Parse Parse;
+typedef struct ParseCleanup ParseCleanup;
+typedef struct PreUpdate PreUpdate;
+typedef struct PrintfArguments PrintfArguments;
+typedef struct RCStr RCStr;
+typedef struct RenameToken RenameToken;
+typedef struct Returning Returning;
+typedef struct RowSet RowSet;
+typedef struct Savepoint Savepoint;
+typedef struct Select Select;
+typedef struct SQLiteThread SQLiteThread;
+typedef struct SelectDest SelectDest;
+typedef struct Subquery Subquery;
+typedef struct SrcItem SrcItem;
+typedef struct SrcList SrcList;
+typedef struct sqlite3_str StrAccum; /* Internal alias for sqlite3_str */
+typedef struct Table Table;
+typedef struct TableLock TableLock;
+typedef struct Token Token;
+typedef struct TreeView TreeView;
+typedef struct Trigger Trigger;
+typedef struct TriggerPrg TriggerPrg;
+typedef struct TriggerStep TriggerStep;
+typedef struct UnpackedRecord UnpackedRecord;
+typedef struct Upsert Upsert;
+typedef struct VTable VTable;
+typedef struct VtabCtx VtabCtx;
+typedef struct Walker Walker;
+typedef struct WhereInfo WhereInfo;
+typedef struct Window Window;
+typedef struct With With;
+
+
+/*
+** The bitmask datatype defined below is used for various optimizations.
+**
+** Changing this from a 64-bit to a 32-bit type limits the number of
+** tables in a join to 32 instead of 64.  But it also reduces the size
+** of the library by 738 bytes on ix86.
+*/
+#ifdef SQLITE_BITMASK_TYPE
+  typedef SQLITE_BITMASK_TYPE Bitmask;
+#else
+  typedef u64 Bitmask;
+#endif
+
+/*
+** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
+*/
+#define BMS  ((int)(sizeof(Bitmask)*8))
+
+/*
+** A bit in a Bitmask
+*/
+#define MASKBIT(n)    (((Bitmask)1)<<(n))
+#define MASKBIT64(n)  (((u64)1)<<(n))
+#define MASKBIT32(n)  (((unsigned int)1)<<(n))
+#define SMASKBIT32(n) ((n)<=31?((unsigned int)1)<<(n):0)
+#define ALLBITS       ((Bitmask)-1)
+#define TOPBIT        (((Bitmask)1)<<(BMS-1))
+
+/* A VList object records a mapping between parameters/variables/wildcards
+** in the SQL statement (such as $abc, @pqr, or :xyz) and the integer
+** variable number associated with that parameter.  See the format description
+** on the sqlite3VListAdd() routine for more information.  A VList is really
+** just an array of integers.
+*/
+typedef int VList;
+
+/*
+** Defer sourcing vdbe.h and btree.h until after the "u8" and
+** "BusyHandler" typedefs. vdbe.h also requires a few of the opaque
+** pointer types (i.e. FuncDef) defined above.
+*/
+/************** Include os.h in the middle of sqliteInt.h ********************/
+/************** Begin file os.h **********************************************/
+/*
+** 2001 September 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file (together with is companion C source-code file
+** "os.c") attempt to abstract the underlying operating system so that
+** the SQLite library will work on both POSIX and windows systems.
+**
+** This header file is #include-ed by sqliteInt.h and thus ends up
+** being included by every source file.
+*/
+#ifndef _SQLITE_OS_H_
+#define _SQLITE_OS_H_
+
+/*
+** Attempt to automatically detect the operating system and setup the
+** necessary pre-processor macros for it.
+*/
+/************** Include os_setup.h in the middle of os.h *********************/
+/************** Begin file os_setup.h ****************************************/
+/*
+** 2013 November 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains pre-processor directives related to operating system
+** detection and/or setup.
+*/
+#ifndef SQLITE_OS_SETUP_H
+#define SQLITE_OS_SETUP_H
+
+/*
+** Figure out if we are dealing with Unix, Windows, or some other operating
+** system.
+**
+** After the following block of preprocess macros, all of
+**
+**    SQLITE_OS_KV
+**    SQLITE_OS_OTHER
+**    SQLITE_OS_UNIX
+**    SQLITE_OS_WIN
+**
+** will defined to either 1 or 0. One of them will be 1. The others will be 0.
+** If none of the macros are initially defined, then select either
+** SQLITE_OS_UNIX or SQLITE_OS_WIN depending on the target platform.
+**
+** If SQLITE_OS_OTHER=1 is specified at compile-time, then the application
+** must provide its own VFS implementation together with sqlite3_os_init()
+** and sqlite3_os_end() routines.
+*/
+#if !defined(SQLITE_OS_KV) && !defined(SQLITE_OS_OTHER) && \
+       !defined(SQLITE_OS_UNIX) && !defined(SQLITE_OS_WIN)
+#  if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || \
+          defined(__MINGW32__) || defined(__BORLANDC__)
+#    define SQLITE_OS_WIN 1
+#    define SQLITE_OS_UNIX 0
+#  else
+#    define SQLITE_OS_WIN 0
+#    define SQLITE_OS_UNIX 1
+#  endif
+#endif
+#if SQLITE_OS_OTHER+1>1
+#  undef SQLITE_OS_KV
+#  define SQLITE_OS_KV 0
+#  undef SQLITE_OS_UNIX
+#  define SQLITE_OS_UNIX 0
+#  undef SQLITE_OS_WIN
+#  define SQLITE_OS_WIN 0
+#endif
+#if SQLITE_OS_KV+1>1
+#  undef SQLITE_OS_OTHER
+#  define SQLITE_OS_OTHER 0
+#  undef SQLITE_OS_UNIX
+#  define SQLITE_OS_UNIX 0
+#  undef SQLITE_OS_WIN
+#  define SQLITE_OS_WIN 0
+#  define SQLITE_OMIT_LOAD_EXTENSION 1
+#  define SQLITE_OMIT_WAL 1
+#  define SQLITE_OMIT_DEPRECATED 1
+#  undef SQLITE_TEMP_STORE
+#  define SQLITE_TEMP_STORE 3  /* Always use memory for temporary storage */
+#  define SQLITE_DQS 0
+#  define SQLITE_OMIT_SHARED_CACHE 1
+#  define SQLITE_OMIT_AUTOINIT 1
+#endif
+#if SQLITE_OS_UNIX+1>1
+#  undef SQLITE_OS_KV
+#  define SQLITE_OS_KV 0
+#  undef SQLITE_OS_OTHER
+#  define SQLITE_OS_OTHER 0
+#  undef SQLITE_OS_WIN
+#  define SQLITE_OS_WIN 0
+#endif
+#if SQLITE_OS_WIN+1>1
+#  undef SQLITE_OS_KV
+#  define SQLITE_OS_KV 0
+#  undef SQLITE_OS_OTHER
+#  define SQLITE_OS_OTHER 0
+#  undef SQLITE_OS_UNIX
+#  define SQLITE_OS_UNIX 0
+#endif
+
+
+#endif /* SQLITE_OS_SETUP_H */
+
+/************** End of os_setup.h ********************************************/
+/************** Continuing where we left off in os.h *************************/
+
+/* If the SET_FULLSYNC macro is not defined above, then make it
+** a no-op
+*/
+#ifndef SET_FULLSYNC
+# define SET_FULLSYNC(x,y)
+#endif
+
+/* Maximum pathname length.  Note: FILENAME_MAX defined by stdio.h
+*/
+#ifndef SQLITE_MAX_PATHLEN
+# define SQLITE_MAX_PATHLEN FILENAME_MAX
+#endif
+
+/* Maximum number of symlinks that will be resolved while trying to
+** expand a filename in xFullPathname() in the VFS.
+*/
+#ifndef SQLITE_MAX_SYMLINK
+# define SQLITE_MAX_SYMLINK 200
+#endif
+
+/*
+** The default size of a disk sector
+*/
+#ifndef SQLITE_DEFAULT_SECTOR_SIZE
+# define SQLITE_DEFAULT_SECTOR_SIZE 4096
+#endif
+
+/*
+** Temporary files are named starting with this prefix followed by 16 random
+** alphanumeric characters, and no file extension. They are stored in the
+** OS's standard temporary file directory, and are deleted prior to exit.
+** If sqlite is being embedded in another program, you may wish to change the
+** prefix to reflect your program's name, so that if your program exits
+** prematurely, old temporary files can be easily identified. This can be done
+** using -DSQLITE_TEMP_FILE_PREFIX=myprefix_ on the compiler command line.
+**
+** 2006-10-31:  The default prefix used to be "sqlite_".  But then
+** Mcafee started using SQLite in their anti-virus product and it
+** started putting files with the "sqlite" name in the c:/temp folder.
+** This annoyed many windows users.  Those users would then do a
+** Google search for "sqlite", find the telephone numbers of the
+** developers and call to wake them up at night and complain.
+** For this reason, the default name prefix is changed to be "sqlite"
+** spelled backwards.  So the temp files are still identified, but
+** anybody smart enough to figure out the code is also likely smart
+** enough to know that calling the developer will not help get rid
+** of the file.
+*/
+#ifndef SQLITE_TEMP_FILE_PREFIX
+# define SQLITE_TEMP_FILE_PREFIX "etilqs_"
+#endif
+
+/*
+** The following values may be passed as the second argument to
+** sqlite3OsLock(). The various locks exhibit the following semantics:
+**
+** SHARED:    Any number of processes may hold a SHARED lock simultaneously.
+** RESERVED:  A single process may hold a RESERVED lock on a file at
+**            any time. Other processes may hold and obtain new SHARED locks.
+** PENDING:   A single process may hold a PENDING lock on a file at
+**            any one time. Existing SHARED locks may persist, but no new
+**            SHARED locks may be obtained by other processes.
+** EXCLUSIVE: An EXCLUSIVE lock precludes all other locks.
+**
+** PENDING_LOCK may not be passed directly to sqlite3OsLock(). Instead, a
+** process that requests an EXCLUSIVE lock may actually obtain a PENDING
+** lock. This can be upgraded to an EXCLUSIVE lock by a subsequent call to
+** sqlite3OsLock().
+*/
+#define NO_LOCK         0
+#define SHARED_LOCK     1
+#define RESERVED_LOCK   2
+#define PENDING_LOCK    3
+#define EXCLUSIVE_LOCK  4
+
+/*
+** File Locking Notes:  (Mostly about windows but also some info for Unix)
+**
+** We cannot use LockFileEx() or UnlockFileEx() on Win95/98/ME because
+** those functions are not available.  So we use only LockFile() and
+** UnlockFile().
+**
+** LockFile() prevents not just writing but also reading by other processes.
+** A SHARED_LOCK is obtained by locking a single randomly-chosen
+** byte out of a specific range of bytes. The lock byte is obtained at
+** random so two separate readers can probably access the file at the
+** same time, unless they are unlucky and choose the same lock byte.
+** An EXCLUSIVE_LOCK is obtained by locking all bytes in the range.
+** There can only be one writer.  A RESERVED_LOCK is obtained by locking
+** a single byte of the file that is designated as the reserved lock byte.
+** A PENDING_LOCK is obtained by locking a designated byte different from
+** the RESERVED_LOCK byte.
+**
+** On WinNT/2K/XP systems, LockFileEx() and UnlockFileEx() are available,
+** which means we can use reader/writer locks.  When reader/writer locks
+** are used, the lock is placed on the same range of bytes that is used
+** for probabilistic locking in Win95/98/ME.  Hence, the locking scheme
+** will support two or more Win95 readers or two or more WinNT readers.
+** But a single Win95 reader will lock out all WinNT readers and a single
+** WinNT reader will lock out all other Win95 readers.
+**
+** The following #defines specify the range of bytes used for locking.
+** SHARED_SIZE is the number of bytes available in the pool from which
+** a random byte is selected for a shared lock.  The pool of bytes for
+** shared locks begins at SHARED_FIRST.
+**
+** The same locking strategy and
+** byte ranges are used for Unix.  This leaves open the possibility of having
+** clients on win95, winNT, and unix all talking to the same shared file
+** and all locking correctly.  To do so would require that samba (or whatever
+** tool is being used for file sharing) implements locks correctly between
+** windows and unix.  I'm guessing that isn't likely to happen, but by
+** using the same locking range we are at least open to the possibility.
+**
+** Locking in windows is manditory.  For this reason, we cannot store
+** actual data in the bytes used for locking.  The pager never allocates
+** the pages involved in locking therefore.  SHARED_SIZE is selected so
+** that all locks will fit on a single page even at the minimum page size.
+** PENDING_BYTE defines the beginning of the locks.  By default PENDING_BYTE
+** is set high so that we don't have to allocate an unused page except
+** for very large databases.  But one should test the page skipping logic
+** by setting PENDING_BYTE low and running the entire regression suite.
+**
+** Changing the value of PENDING_BYTE results in a subtly incompatible
+** file format.  Depending on how it is changed, you might not notice
+** the incompatibility right away, even running a full regression test.
+** The default location of PENDING_BYTE is the first byte past the
+** 1GB boundary.
+**
+*/
+#ifdef SQLITE_OMIT_WSD
+# define PENDING_BYTE     (0x40000000)
+#else
+# define PENDING_BYTE      sqlite3PendingByte
+#endif
+#define RESERVED_BYTE     (PENDING_BYTE+1)
+#define SHARED_FIRST      (PENDING_BYTE+2)
+#define SHARED_SIZE       510
+
+/*
+** Wrapper around OS specific sqlite3_os_init() function.
+*/
+SQLITE_PRIVATE int sqlite3OsInit(void);
+
+/*
+** Functions for accessing sqlite3_file methods
+*/
+SQLITE_PRIVATE void sqlite3OsClose(sqlite3_file*);
+SQLITE_PRIVATE int sqlite3OsRead(sqlite3_file*, void*, int amt, i64 offset);
+SQLITE_PRIVATE int sqlite3OsWrite(sqlite3_file*, const void*, int amt, i64 offset);
+SQLITE_PRIVATE int sqlite3OsTruncate(sqlite3_file*, i64 size);
+SQLITE_PRIVATE int sqlite3OsSync(sqlite3_file*, int);
+SQLITE_PRIVATE int sqlite3OsFileSize(sqlite3_file*, i64 *pSize);
+SQLITE_PRIVATE int sqlite3OsLock(sqlite3_file*, int);
+SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file*, int);
+SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut);
+SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file*,int,void*);
+SQLITE_PRIVATE void sqlite3OsFileControlHint(sqlite3_file*,int,void*);
+#define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0
+SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id);
+SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id);
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE int sqlite3OsShmMap(sqlite3_file *,int,int,int,void volatile **);
+SQLITE_PRIVATE int sqlite3OsShmLock(sqlite3_file *id, int, int, int);
+SQLITE_PRIVATE void sqlite3OsShmBarrier(sqlite3_file *id);
+SQLITE_PRIVATE int sqlite3OsShmUnmap(sqlite3_file *id, int);
+#endif /* SQLITE_OMIT_WAL */
+SQLITE_PRIVATE int sqlite3OsFetch(sqlite3_file *id, i64, int, void **);
+SQLITE_PRIVATE int sqlite3OsUnfetch(sqlite3_file *, i64, void *);
+
+
+/*
+** Functions for accessing sqlite3_vfs methods
+*/
+SQLITE_PRIVATE int sqlite3OsOpen(sqlite3_vfs *, const char *, sqlite3_file*, int, int *);
+SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *, const char *, int);
+SQLITE_PRIVATE int sqlite3OsAccess(sqlite3_vfs *, const char *, int, int *pResOut);
+SQLITE_PRIVATE int sqlite3OsFullPathname(sqlite3_vfs *, const char *, int, char *);
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *, const char *);
+SQLITE_PRIVATE void sqlite3OsDlError(sqlite3_vfs *, int, char *);
+SQLITE_PRIVATE void (*sqlite3OsDlSym(sqlite3_vfs *, void *, const char *))(void);
+SQLITE_PRIVATE void sqlite3OsDlClose(sqlite3_vfs *, void *);
+#endif /* SQLITE_OMIT_LOAD_EXTENSION */
+SQLITE_PRIVATE int sqlite3OsRandomness(sqlite3_vfs *, int, char *);
+SQLITE_PRIVATE int sqlite3OsSleep(sqlite3_vfs *, int);
+SQLITE_PRIVATE int sqlite3OsGetLastError(sqlite3_vfs*);
+SQLITE_PRIVATE int sqlite3OsCurrentTimeInt64(sqlite3_vfs *, sqlite3_int64*);
+
+/*
+** Convenience functions for opening and closing files using
+** sqlite3_malloc() to obtain space for the file-handle structure.
+*/
+SQLITE_PRIVATE int sqlite3OsOpenMalloc(sqlite3_vfs *, const char *, sqlite3_file **, int,int*);
+SQLITE_PRIVATE void sqlite3OsCloseFree(sqlite3_file *);
+
+#endif /* _SQLITE_OS_H_ */
+
+/************** End of os.h **************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include pager.h in the middle of sqliteInt.h *****************/
+/************** Begin file pager.h *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite page cache
+** subsystem.  The page cache subsystem reads and writes a file a page
+** at a time and provides a journal for rollback.
+*/
+
+#ifndef SQLITE_PAGER_H
+#define SQLITE_PAGER_H
+
+/*
+** Default maximum size for persistent journal files. A negative
+** value means no limit. This value may be overridden using the
+** sqlite3PagerJournalSizeLimit() API. See also "PRAGMA journal_size_limit".
+*/
+#ifndef SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT
+  #define SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT -1
+#endif
+
+/*
+** The type used to represent a page number.  The first page in a file
+** is called page 1.  0 is used to represent "not a page".
+*/
+typedef u32 Pgno;
+
+/*
+** Each open file is managed by a separate instance of the "Pager" structure.
+*/
+typedef struct Pager Pager;
+
+/*
+** Handle type for pages.
+*/
+typedef struct PgHdr DbPage;
+
+/*
+** Page number PAGER_SJ_PGNO is never used in an SQLite database (it is
+** reserved for working around a windows/posix incompatibility). It is
+** used in the journal to signify that the remainder of the journal file
+** is devoted to storing a super-journal name - there are no more pages to
+** roll back. See comments for function writeSuperJournal() in pager.c
+** for details.
+*/
+#define PAGER_SJ_PGNO_COMPUTED(x) ((Pgno)((PENDING_BYTE/((x)->pageSize))+1))
+#define PAGER_SJ_PGNO(x)          ((x)->lckPgno)
+
+/*
+** Allowed values for the flags parameter to sqlite3PagerOpen().
+**
+** NOTE: These values must match the corresponding BTREE_ values in btree.h.
+*/
+#define PAGER_OMIT_JOURNAL  0x0001    /* Do not use a rollback journal */
+#define PAGER_MEMORY        0x0002    /* In-memory database */
+
+/*
+** Valid values for the second argument to sqlite3PagerLockingMode().
+*/
+#define PAGER_LOCKINGMODE_QUERY      -1
+#define PAGER_LOCKINGMODE_NORMAL      0
+#define PAGER_LOCKINGMODE_EXCLUSIVE   1
+
+/*
+** Numeric constants that encode the journalmode.
+**
+** The numeric values encoded here (other than PAGER_JOURNALMODE_QUERY)
+** are exposed in the API via the "PRAGMA journal_mode" command and
+** therefore cannot be changed without a compatibility break.
+*/
+#define PAGER_JOURNALMODE_QUERY     (-1)  /* Query the value of journalmode */
+#define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */
+#define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */
+#define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */
+#define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */
+#define PAGER_JOURNALMODE_MEMORY      4   /* In-memory journal file */
+#define PAGER_JOURNALMODE_WAL         5   /* Use write-ahead logging */
+
+#define isWalMode(x) ((x)==PAGER_JOURNALMODE_WAL)
+
+/*
+** The argument to this macro is a file descriptor (type sqlite3_file*).
+** Return 0 if it is not open, or non-zero (but not 1) if it is.
+**
+** This is so that expressions can be written as:
+**
+**   if( isOpen(pPager->jfd) ){ ...
+**
+** instead of
+**
+**   if( pPager->jfd->pMethods ){ ...
+*/
+#define isOpen(pFd) ((pFd)->pMethods!=0)
+
+/*
+** Flags that make up the mask passed to sqlite3PagerGet().
+*/
+#define PAGER_GET_NOCONTENT     0x01  /* Do not load data from disk */
+#define PAGER_GET_READONLY      0x02  /* Read-only page is acceptable */
+
+/*
+** Flags for sqlite3PagerSetFlags()
+**
+** Value constraints (enforced via assert()):
+**    PAGER_FULLFSYNC      == SQLITE_FullFSync
+**    PAGER_CKPT_FULLFSYNC == SQLITE_CkptFullFSync
+**    PAGER_CACHE_SPILL    == SQLITE_CacheSpill
+*/
+#define PAGER_SYNCHRONOUS_OFF       0x01  /* PRAGMA synchronous=OFF */
+#define PAGER_SYNCHRONOUS_NORMAL    0x02  /* PRAGMA synchronous=NORMAL */
+#define PAGER_SYNCHRONOUS_FULL      0x03  /* PRAGMA synchronous=FULL */
+#define PAGER_SYNCHRONOUS_EXTRA     0x04  /* PRAGMA synchronous=EXTRA */
+#define PAGER_SYNCHRONOUS_MASK      0x07  /* Mask for four values above */
+#define PAGER_FULLFSYNC             0x08  /* PRAGMA fullfsync=ON */
+#define PAGER_CKPT_FULLFSYNC        0x10  /* PRAGMA checkpoint_fullfsync=ON */
+#define PAGER_CACHESPILL            0x20  /* PRAGMA cache_spill=ON */
+#define PAGER_FLAGS_MASK            0x38  /* All above except SYNCHRONOUS */
+
+/*
+** The remainder of this file contains the declarations of the functions
+** that make up the Pager sub-system API. See source code comments for
+** a detailed description of each routine.
+*/
+
+/* Open and close a Pager connection. */
+SQLITE_PRIVATE int sqlite3PagerOpen(
+  sqlite3_vfs*,
+  Pager **ppPager,
+  const char*,
+  int,
+  int,
+  int,
+  void(*)(DbPage*)
+);
+SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager, sqlite3*);
+SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
+
+/* Functions used to configure a Pager object. */
+SQLITE_PRIVATE void sqlite3PagerSetBusyHandler(Pager*, int(*)(void *), void *);
+SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager*, u32*, int);
+SQLITE_PRIVATE Pgno sqlite3PagerMaxPageCount(Pager*, Pgno);
+SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager*, int);
+SQLITE_PRIVATE int sqlite3PagerSetSpillsize(Pager*, int);
+SQLITE_PRIVATE void sqlite3PagerSetMmapLimit(Pager *, sqlite3_int64);
+SQLITE_PRIVATE void sqlite3PagerShrink(Pager*);
+SQLITE_PRIVATE void sqlite3PagerSetFlags(Pager*,unsigned);
+SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *, int);
+SQLITE_PRIVATE int sqlite3PagerSetJournalMode(Pager *, int);
+SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager*);
+SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager*);
+SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
+SQLITE_PRIVATE sqlite3_backup **sqlite3PagerBackupPtr(Pager*);
+SQLITE_PRIVATE int sqlite3PagerFlush(Pager*);
+
+/* Functions used to obtain and release page references. */
+SQLITE_PRIVATE int sqlite3PagerGet(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag);
+SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno);
+SQLITE_PRIVATE void sqlite3PagerRef(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerUnref(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerUnrefNotNull(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerUnrefPageOne(DbPage*);
+
+/* Operations on page references. */
+SQLITE_PRIVATE int sqlite3PagerWrite(DbPage*);
+SQLITE_PRIVATE void sqlite3PagerDontWrite(DbPage*);
+SQLITE_PRIVATE int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int);
+SQLITE_PRIVATE int sqlite3PagerPageRefcount(DbPage*);
+SQLITE_PRIVATE void *sqlite3PagerGetData(DbPage *);
+SQLITE_PRIVATE void *sqlite3PagerGetExtra(DbPage *);
+
+/* Functions used to manage pager transactions and savepoints. */
+SQLITE_PRIVATE void sqlite3PagerPagecount(Pager*, int*);
+SQLITE_PRIVATE int sqlite3PagerBegin(Pager*, int exFlag, int);
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(Pager*,const char *zSuper, int);
+SQLITE_PRIVATE int sqlite3PagerExclusiveLock(Pager*);
+SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager, const char *zSuper);
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager*);
+SQLITE_PRIVATE int sqlite3PagerRollback(Pager*);
+SQLITE_PRIVATE int sqlite3PagerOpenSavepoint(Pager *pPager, int n);
+SQLITE_PRIVATE int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);
+SQLITE_PRIVATE int sqlite3PagerSharedLock(Pager *pPager);
+
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE   int sqlite3PagerCheckpoint(Pager *pPager, sqlite3*, int, int*, int*);
+SQLITE_PRIVATE   int sqlite3PagerWalSupported(Pager *pPager);
+SQLITE_PRIVATE   int sqlite3PagerWalCallback(Pager *pPager);
+SQLITE_PRIVATE   int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
+SQLITE_PRIVATE   int sqlite3PagerCloseWal(Pager *pPager, sqlite3*);
+# ifdef SQLITE_ENABLE_SNAPSHOT
+SQLITE_PRIVATE   int sqlite3PagerSnapshotGet(Pager*, sqlite3_snapshot **ppSnapshot);
+SQLITE_PRIVATE   int sqlite3PagerSnapshotOpen(Pager*, sqlite3_snapshot *pSnapshot);
+SQLITE_PRIVATE   int sqlite3PagerSnapshotRecover(Pager *pPager);
+SQLITE_PRIVATE   int sqlite3PagerSnapshotCheck(Pager *pPager, sqlite3_snapshot *pSnapshot);
+SQLITE_PRIVATE   void sqlite3PagerSnapshotUnlock(Pager *pPager);
+# endif
+#endif
+
+#if !defined(SQLITE_OMIT_WAL) && defined(SQLITE_ENABLE_SETLK_TIMEOUT)
+SQLITE_PRIVATE   int sqlite3PagerWalWriteLock(Pager*, int);
+SQLITE_PRIVATE   void sqlite3PagerWalDb(Pager*, sqlite3*);
+#else
+# define sqlite3PagerWalWriteLock(y,z) SQLITE_OK
+# define sqlite3PagerWalDb(x,y)
+#endif
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+SQLITE_PRIVATE   int sqlite3PagerDirectReadOk(Pager *pPager, Pgno pgno);
+#endif
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+SQLITE_PRIVATE   int sqlite3PagerWalFramesize(Pager *pPager);
+#endif
+
+/* Functions used to query pager state and configuration. */
+SQLITE_PRIVATE u8 sqlite3PagerIsreadonly(Pager*);
+SQLITE_PRIVATE u32 sqlite3PagerDataVersion(Pager*);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   int sqlite3PagerRefcount(Pager*);
+#endif
+SQLITE_PRIVATE int sqlite3PagerMemUsed(Pager*);
+SQLITE_PRIVATE const char *sqlite3PagerFilename(const Pager*, int);
+SQLITE_PRIVATE sqlite3_vfs *sqlite3PagerVfs(Pager*);
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerFile(Pager*);
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerJrnlFile(Pager*);
+SQLITE_PRIVATE const char *sqlite3PagerJournalname(Pager*);
+SQLITE_PRIVATE void *sqlite3PagerTempSpace(Pager*);
+SQLITE_PRIVATE int sqlite3PagerIsMemdb(Pager*);
+SQLITE_PRIVATE void sqlite3PagerCacheStat(Pager *, int, int, u64*);
+SQLITE_PRIVATE void sqlite3PagerClearCache(Pager*);
+SQLITE_PRIVATE int sqlite3SectorSize(sqlite3_file *);
+
+/* Functions used to truncate the database file. */
+SQLITE_PRIVATE void sqlite3PagerTruncateImage(Pager*,Pgno);
+
+SQLITE_PRIVATE void sqlite3PagerRekey(DbPage*, Pgno, u16);
+
+/* Functions to support testing and debugging. */
+#if !defined(NDEBUG) || defined(SQLITE_TEST)
+SQLITE_PRIVATE   Pgno sqlite3PagerPagenumber(DbPage*);
+SQLITE_PRIVATE   int sqlite3PagerIswriteable(DbPage*);
+#endif
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE   int *sqlite3PagerStats(Pager*);
+SQLITE_PRIVATE   void sqlite3PagerRefdump(Pager*);
+  void disable_simulated_io_errors(void);
+  void enable_simulated_io_errors(void);
+#else
+# define disable_simulated_io_errors()
+# define enable_simulated_io_errors()
+#endif
+
+#if defined(SQLITE_USE_SEH) && !defined(SQLITE_OMIT_WAL)
+SQLITE_PRIVATE int sqlite3PagerWalSystemErrno(Pager*);
+#endif
+
+#endif /* SQLITE_PAGER_H */
+
+/************** End of pager.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include btree.h in the middle of sqliteInt.h *****************/
+/************** Begin file btree.h *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite B-Tree file
+** subsystem.  See comments in the source code for a detailed description
+** of what each interface routine does.
+*/
+#ifndef SQLITE_BTREE_H
+#define SQLITE_BTREE_H
+
+/* TODO: This definition is just included so other modules compile. It
+** needs to be revisited.
+*/
+#define SQLITE_N_BTREE_META 16
+
+/*
+** If defined as non-zero, auto-vacuum is enabled by default. Otherwise
+** it must be turned on for each database using "PRAGMA auto_vacuum = 1".
+*/
+#ifndef SQLITE_DEFAULT_AUTOVACUUM
+  #define SQLITE_DEFAULT_AUTOVACUUM 0
+#endif
+
+#define BTREE_AUTOVACUUM_NONE 0        /* Do not do auto-vacuum */
+#define BTREE_AUTOVACUUM_FULL 1        /* Do full auto-vacuum */
+#define BTREE_AUTOVACUUM_INCR 2        /* Incremental vacuum */
+
+/*
+** Forward declarations of structure
+*/
+typedef struct Btree Btree;
+typedef struct BtCursor BtCursor;
+typedef struct BtShared BtShared;
+typedef struct BtreePayload BtreePayload;
+
+
+SQLITE_PRIVATE int sqlite3BtreeOpen(
+  sqlite3_vfs *pVfs,       /* VFS to use with this b-tree */
+  const char *zFilename,   /* Name of database file to open */
+  sqlite3 *db,             /* Associated database connection */
+  Btree **ppBtree,         /* Return open Btree* here */
+  int flags,               /* Flags */
+  int vfsFlags             /* Flags passed through to VFS open */
+);
+
+/* The flags parameter to sqlite3BtreeOpen can be the bitwise or of the
+** following values.
+**
+** NOTE:  These values must match the corresponding PAGER_ values in
+** pager.h.
+*/
+#define BTREE_OMIT_JOURNAL  1  /* Do not create or use a rollback journal */
+#define BTREE_MEMORY        2  /* This is an in-memory DB */
+#define BTREE_SINGLE        4  /* The file contains at most 1 b-tree */
+#define BTREE_UNORDERED     8  /* Use of a hash implementation is OK */
+
+SQLITE_PRIVATE int sqlite3BtreeClose(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeSetSpillSize(Btree*,int);
+#if SQLITE_MAX_MMAP_SIZE>0
+SQLITE_PRIVATE   int sqlite3BtreeSetMmapLimit(Btree*,sqlite3_int64);
+#endif
+SQLITE_PRIVATE int sqlite3BtreeSetPagerFlags(Btree*,unsigned);
+SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int nPagesize, int nReserve, int eFix);
+SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree*);
+SQLITE_PRIVATE Pgno sqlite3BtreeMaxPageCount(Btree*,Pgno);
+SQLITE_PRIVATE Pgno sqlite3BtreeLastPage(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeSecureDelete(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeGetRequestedReserve(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeGetReserveNoMutex(Btree *p);
+SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *, int);
+SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *);
+SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree*,int,int*);
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree*, const char*);
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree*, int);
+SQLITE_PRIVATE int sqlite3BtreeCommit(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeRollback(Btree*,int,int);
+SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree*,int);
+SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree*, Pgno*, int flags);
+SQLITE_PRIVATE int sqlite3BtreeTxnState(Btree*);
+SQLITE_PRIVATE int sqlite3BtreeIsInBackup(Btree*);
+
+SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *, int, void(*)(void *));
+SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *pBtree);
+#ifndef SQLITE_OMIT_SHARED_CACHE
+SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *pBtree, int iTab, u8 isWriteLock);
+#endif
+
+/* Savepoints are named, nestable SQL transactions mostly implemented */
+/* in vdbe.c and pager.c See https://sqlite.org/lang_savepoint.html */
+SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *, int, int);
+
+/* "Checkpoint" only refers to WAL. See https://sqlite.org/wal.html#ckpt */
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE   int sqlite3BtreeCheckpoint(Btree*, int, int *, int *);
+#endif
+
+SQLITE_PRIVATE const char *sqlite3BtreeGetFilename(Btree *);
+SQLITE_PRIVATE const char *sqlite3BtreeGetJournalname(Btree *);
+SQLITE_PRIVATE int sqlite3BtreeCopyFile(Btree *, Btree *);
+
+SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *);
+
+/* The flags parameter to sqlite3BtreeCreateTable can be the bitwise OR
+** of the flags shown below.
+**
+** Every SQLite table must have either BTREE_INTKEY or BTREE_BLOBKEY set.
+** With BTREE_INTKEY, the table key is a 64-bit integer and arbitrary data
+** is stored in the leaves.  (BTREE_INTKEY is used for SQL tables.)  With
+** BTREE_BLOBKEY, the key is an arbitrary BLOB and no content is stored
+** anywhere - the key is the content.  (BTREE_BLOBKEY is used for SQL
+** indices.)
+*/
+#define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
+#define BTREE_BLOBKEY    2    /* Table has keys only - no data */
+
+SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree*, int, int*);
+SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree*, int, i64*);
+SQLITE_PRIVATE int sqlite3BtreeClearTableOfCursor(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreeTripAllCursors(Btree*, int, int);
+
+SQLITE_PRIVATE void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue);
+SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);
+
+SQLITE_PRIVATE int sqlite3BtreeNewDb(Btree *p);
+
+/*
+** The second parameter to sqlite3BtreeGetMeta or sqlite3BtreeUpdateMeta
+** should be one of the following values. The integer values are assigned
+** to constants so that the offset of the corresponding field in an
+** SQLite database header may be found using the following formula:
+**
+**   offset = 36 + (idx * 4)
+**
+** For example, the free-page-count field is located at byte offset 36 of
+** the database file header. The incr-vacuum-flag field is located at
+** byte offset 64 (== 36+4*7).
+**
+** The BTREE_DATA_VERSION value is not really a value stored in the header.
+** It is a read-only number computed by the pager.  But we merge it with
+** the header value access routines since its access pattern is the same.
+** Call it a "virtual meta value".
+*/
+#define BTREE_FREE_PAGE_COUNT     0
+#define BTREE_SCHEMA_VERSION      1
+#define BTREE_FILE_FORMAT         2
+#define BTREE_DEFAULT_CACHE_SIZE  3
+#define BTREE_LARGEST_ROOT_PAGE   4
+#define BTREE_TEXT_ENCODING       5
+#define BTREE_USER_VERSION        6
+#define BTREE_INCR_VACUUM         7
+#define BTREE_APPLICATION_ID      8
+#define BTREE_DATA_VERSION        15  /* A virtual meta-value */
+
+/*
+** Kinds of hints that can be passed into the sqlite3BtreeCursorHint()
+** interface.
+**
+** BTREE_HINT_RANGE  (arguments: Expr*, Mem*)
+**
+**     The first argument is an Expr* (which is guaranteed to be constant for
+**     the lifetime of the cursor) that defines constraints on which rows
+**     might be fetched with this cursor.  The Expr* tree may contain
+**     TK_REGISTER nodes that refer to values stored in the array of registers
+**     passed as the second parameter.  In other words, if Expr.op==TK_REGISTER
+**     then the value of the node is the value in Mem[pExpr.iTable].  Any
+**     TK_COLUMN node in the expression tree refers to the Expr.iColumn-th
+**     column of the b-tree of the cursor.  The Expr tree will not contain
+**     any function calls nor subqueries nor references to b-trees other than
+**     the cursor being hinted.
+**
+**     The design of the _RANGE hint is aid b-tree implementations that try
+**     to prefetch content from remote machines - to provide those
+**     implementations with limits on what needs to be prefetched and thereby
+**     reduce network bandwidth.
+**
+** Note that BTREE_HINT_FLAGS with BTREE_BULKLOAD is the only hint used by
+** standard SQLite.  The other hints are provided for extensions that use
+** the SQLite parser and code generator but substitute their own storage
+** engine.
+*/
+#define BTREE_HINT_RANGE 0       /* Range constraints on queries */
+
+/*
+** Values that may be OR'd together to form the argument to the
+** BTREE_HINT_FLAGS hint for sqlite3BtreeCursorHint():
+**
+** The BTREE_BULKLOAD flag is set on index cursors when the index is going
+** to be filled with content that is already in sorted order.
+**
+** The BTREE_SEEK_EQ flag is set on cursors that will get OP_SeekGE or
+** OP_SeekLE opcodes for a range search, but where the range of entries
+** selected will all have the same key.  In other words, the cursor will
+** be used only for equality key searches.
+**
+*/
+#define BTREE_BULKLOAD 0x00000001  /* Used to full index in sorted order */
+#define BTREE_SEEK_EQ  0x00000002  /* EQ seeks only - no range seeks */
+
+/*
+** Flags passed as the third argument to sqlite3BtreeCursor().
+**
+** For read-only cursors the wrFlag argument is always zero. For read-write
+** cursors it may be set to either (BTREE_WRCSR|BTREE_FORDELETE) or just
+** (BTREE_WRCSR). If the BTREE_FORDELETE bit is set, then the cursor will
+** only be used by SQLite for the following:
+**
+**   * to seek to and then delete specific entries, and/or
+**
+**   * to read values that will be used to create keys that other
+**     BTREE_FORDELETE cursors will seek to and delete.
+**
+** The BTREE_FORDELETE flag is an optimization hint.  It is not used by
+** by this, the native b-tree engine of SQLite, but it is available to
+** alternative storage engines that might be substituted in place of this
+** b-tree system.  For alternative storage engines in which a delete of
+** the main table row automatically deletes corresponding index rows,
+** the FORDELETE flag hint allows those alternative storage engines to
+** skip a lot of work.  Namely:  FORDELETE cursors may treat all SEEK
+** and DELETE operations as no-ops, and any READ operation against a
+** FORDELETE cursor may return a null row: 0x01 0x00.
+*/
+#define BTREE_WRCSR     0x00000004     /* read-write cursor */
+#define BTREE_FORDELETE 0x00000008     /* Cursor is for seek/delete only */
+
+SQLITE_PRIVATE int sqlite3BtreeCursor(
+  Btree*,                              /* BTree containing table to open */
+  Pgno iTable,                         /* Index of root page */
+  int wrFlag,                          /* 1 for writing.  0 for read-only */
+  struct KeyInfo*,                     /* First argument to compare function */
+  BtCursor *pCursor                    /* Space to write cursor structure */
+);
+SQLITE_PRIVATE BtCursor *sqlite3BtreeFakeValidCursor(void);
+SQLITE_PRIVATE int sqlite3BtreeCursorSize(void);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3BtreeClosesWithCursor(Btree*,BtCursor*);
+#endif
+SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor*);
+SQLITE_PRIVATE void sqlite3BtreeCursorHintFlags(BtCursor*, unsigned);
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+SQLITE_PRIVATE void sqlite3BtreeCursorHint(BtCursor*, int, ...);
+#endif
+
+SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreeTableMoveto(
+  BtCursor*,
+  i64 intKey,
+  int bias,
+  int *pRes
+);
+SQLITE_PRIVATE int sqlite3BtreeIndexMoveto(
+  BtCursor*,
+  UnpackedRecord *pUnKey,
+  int *pRes
+);
+SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreeCursorRestore(BtCursor*, int*);
+SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor*, u8 flags);
+
+/* Allowed flags for sqlite3BtreeDelete() and sqlite3BtreeInsert() */
+#define BTREE_SAVEPOSITION 0x02  /* Leave cursor pointing at NEXT or PREV */
+#define BTREE_AUXDELETE    0x04  /* not the primary delete operation */
+#define BTREE_APPEND       0x08  /* Insert is likely an append */
+#define BTREE_PREFORMAT    0x80  /* Inserted data is a preformated cell */
+
+/* An instance of the BtreePayload object describes the content of a single
+** entry in either an index or table btree.
+**
+** Index btrees (used for indexes and also WITHOUT ROWID tables) contain
+** an arbitrary key and no data.  These btrees have pKey,nKey set to the
+** key and the pData,nData,nZero fields are uninitialized.  The aMem,nMem
+** fields give an array of Mem objects that are a decomposition of the key.
+** The nMem field might be zero, indicating that no decomposition is available.
+**
+** Table btrees (used for rowid tables) contain an integer rowid used as
+** the key and passed in the nKey field.  The pKey field is zero.
+** pData,nData hold the content of the new entry.  nZero extra zero bytes
+** are appended to the end of the content when constructing the entry.
+** The aMem,nMem fields are uninitialized for table btrees.
+**
+** Field usage summary:
+**
+**               Table BTrees                   Index Btrees
+**
+**   pKey        always NULL                    encoded key
+**   nKey        the ROWID                      length of pKey
+**   pData       data                           not used
+**   aMem        not used                       decomposed key value
+**   nMem        not used                       entries in aMem
+**   nData       length of pData                not used
+**   nZero       extra zeros after pData        not used
+**
+** This object is used to pass information into sqlite3BtreeInsert().  The
+** same information used to be passed as five separate parameters.  But placing
+** the information into this object helps to keep the interface more
+** organized and understandable, and it also helps the resulting code to
+** run a little faster by using fewer registers for parameter passing.
+*/
+struct BtreePayload {
+  const void *pKey;       /* Key content for indexes.  NULL for tables */
+  sqlite3_int64 nKey;     /* Size of pKey for indexes.  PRIMARY KEY for tabs */
+  const void *pData;      /* Data for tables. */
+  sqlite3_value *aMem;    /* First of nMem value in the unpacked pKey */
+  u16 nMem;               /* Number of aMem[] value.  Might be zero */
+  int nData;              /* Size of pData.  0 if none. */
+  int nZero;              /* Extra zero data appended after pData,nData */
+};
+
+SQLITE_PRIVATE int sqlite3BtreeInsert(BtCursor*, const BtreePayload *pPayload,
+                       int flags, int seekResult);
+SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor*, int *pRes);
+SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor*, int *pRes);
+SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor*, int flags);
+SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor*, int flags);
+SQLITE_PRIVATE i64 sqlite3BtreeIntegerKey(BtCursor*);
+SQLITE_PRIVATE void sqlite3BtreeCursorPin(BtCursor*);
+SQLITE_PRIVATE void sqlite3BtreeCursorUnpin(BtCursor*);
+SQLITE_PRIVATE i64 sqlite3BtreeOffset(BtCursor*);
+SQLITE_PRIVATE int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*);
+SQLITE_PRIVATE const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt);
+SQLITE_PRIVATE u32 sqlite3BtreePayloadSize(BtCursor*);
+SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor*);
+
+SQLITE_PRIVATE int sqlite3BtreeIntegrityCheck(
+  sqlite3 *db,  /* Database connection that is running the check */
+  Btree *p,     /* The btree to be checked */
+  Pgno *aRoot,  /* An array of root pages numbers for individual trees */
+  sqlite3_value *aCnt,  /* OUT: entry counts for each btree in aRoot[] */
+  int nRoot,    /* Number of entries in aRoot[] */
+  int mxErr,    /* Stop reporting errors after this many */
+  int *pnErr,   /* OUT: Write number of errors seen to this variable */
+  char **pzOut  /* OUT: Write the error message string here */
+);
+SQLITE_PRIVATE struct Pager *sqlite3BtreePager(Btree*);
+SQLITE_PRIVATE i64 sqlite3BtreeRowCountEst(BtCursor*);
+
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE int sqlite3BtreePayloadChecked(BtCursor*, u32 offset, u32 amt, void*);
+SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*);
+SQLITE_PRIVATE void sqlite3BtreeIncrblobCursor(BtCursor *);
+#endif
+SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *);
+SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBt, int iVersion);
+SQLITE_PRIVATE int sqlite3BtreeCursorHasHint(BtCursor*, unsigned int mask);
+SQLITE_PRIVATE int sqlite3BtreeIsReadonly(Btree *pBt);
+SQLITE_PRIVATE int sqlite3HeaderSizeBtree(void);
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE sqlite3_uint64 sqlite3BtreeSeekCount(Btree*);
+#else
+# define sqlite3BtreeSeekCount(X) 0
+#endif
+
+#ifndef NDEBUG
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValid(BtCursor*);
+#endif
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValidNN(BtCursor*);
+
+SQLITE_PRIVATE int sqlite3BtreeCount(sqlite3*, BtCursor*, i64*);
+
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE int sqlite3BtreeCursorInfo(BtCursor*, int*, int);
+SQLITE_PRIVATE void sqlite3BtreeCursorList(Btree*);
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE   int sqlite3BtreeCheckpoint(Btree*, int, int *, int *);
+#endif
+
+SQLITE_PRIVATE int sqlite3BtreeTransferRow(BtCursor*, BtCursor*, i64);
+
+SQLITE_PRIVATE void sqlite3BtreeClearCache(Btree*);
+
+/*
+** If we are not using shared cache, then there is no need to
+** use mutexes to access the BtShared structures.  So make the
+** Enter and Leave procedures no-ops.
+*/
+#ifndef SQLITE_OMIT_SHARED_CACHE
+SQLITE_PRIVATE   void sqlite3BtreeEnter(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeEnterAll(sqlite3*);
+SQLITE_PRIVATE   int sqlite3BtreeSharable(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeEnterCursor(BtCursor*);
+SQLITE_PRIVATE   int sqlite3BtreeConnectionCount(Btree*);
+#else
+# define sqlite3BtreeEnter(X)
+# define sqlite3BtreeEnterAll(X)
+# define sqlite3BtreeSharable(X) 0
+# define sqlite3BtreeEnterCursor(X)
+# define sqlite3BtreeConnectionCount(X) 1
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
+SQLITE_PRIVATE   void sqlite3BtreeLeave(Btree*);
+SQLITE_PRIVATE   void sqlite3BtreeLeaveCursor(BtCursor*);
+SQLITE_PRIVATE   void sqlite3BtreeLeaveAll(sqlite3*);
+#ifndef NDEBUG
+  /* These routines are used inside assert() statements only. */
+SQLITE_PRIVATE   int sqlite3BtreeHoldsMutex(Btree*);
+SQLITE_PRIVATE   int sqlite3BtreeHoldsAllMutexes(sqlite3*);
+SQLITE_PRIVATE   int sqlite3SchemaMutexHeld(sqlite3*,int,Schema*);
+#endif
+#else
+
+# define sqlite3BtreeLeave(X)
+# define sqlite3BtreeLeaveCursor(X)
+# define sqlite3BtreeLeaveAll(X)
+
+# define sqlite3BtreeHoldsMutex(X) 1
+# define sqlite3BtreeHoldsAllMutexes(X) 1
+# define sqlite3SchemaMutexHeld(X,Y,Z) 1
+#endif
+
+
+#endif /* SQLITE_BTREE_H */
+
+/************** End of btree.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include vdbe.h in the middle of sqliteInt.h ******************/
+/************** Begin file vdbe.h ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Header file for the Virtual DataBase Engine (VDBE)
+**
+** This header defines the interface to the virtual database engine
+** or VDBE.  The VDBE implements an abstract machine that runs a
+** simple program to access and modify the underlying database.
+*/
+#ifndef SQLITE_VDBE_H
+#define SQLITE_VDBE_H
+/* #include <stdio.h> */
+
+/*
+** A single VDBE is an opaque structure named "Vdbe".  Only routines
+** in the source file sqliteVdbe.c are allowed to see the insides
+** of this structure.
+*/
+typedef struct Vdbe Vdbe;
+
+/*
+** The names of the following types declared in vdbeInt.h are required
+** for the VdbeOp definition.
+*/
+typedef struct sqlite3_value Mem;
+typedef struct SubProgram SubProgram;
+typedef struct SubrtnSig SubrtnSig;
+
+/*
+** A signature for a reusable subroutine that materializes the RHS of
+** an IN operator.
+*/
+struct SubrtnSig {
+  int selId;          /* SELECT-id for the SELECT statement on the RHS */
+  u8 bComplete;       /* True if fully coded and available for reusable */
+  char *zAff;         /* Affinity of the overall IN expression */
+  int iTable;         /* Ephemeral table generated by the subroutine */
+  int iAddr;          /* Subroutine entry address */
+  int regReturn;      /* Register used to hold return address */
+};
+
+/*
+** A single instruction of the virtual machine has an opcode
+** and as many as three operands.  The instruction is recorded
+** as an instance of the following structure:
+*/
+struct VdbeOp {
+  u8 opcode;          /* What operation to perform */
+  signed char p4type; /* One of the P4_xxx constants for p4 */
+  u16 p5;             /* Fifth parameter is an unsigned 16-bit integer */
+  int p1;             /* First operand */
+  int p2;             /* Second parameter (often the jump destination) */
+  int p3;             /* The third parameter */
+  union p4union {     /* fourth parameter */
+    int i;                 /* Integer value if p4type==P4_INT32 */
+    void *p;               /* Generic pointer */
+    char *z;               /* Pointer to data for string (char array) types */
+    i64 *pI64;             /* Used when p4type is P4_INT64 */
+    double *pReal;         /* Used when p4type is P4_REAL */
+    FuncDef *pFunc;        /* Used when p4type is P4_FUNCDEF */
+    sqlite3_context *pCtx; /* Used when p4type is P4_FUNCCTX */
+    CollSeq *pColl;        /* Used when p4type is P4_COLLSEQ */
+    Mem *pMem;             /* Used when p4type is P4_MEM */
+    VTable *pVtab;         /* Used when p4type is P4_VTAB */
+    KeyInfo *pKeyInfo;     /* Used when p4type is P4_KEYINFO */
+    u32 *ai;               /* Used when p4type is P4_INTARRAY */
+    SubProgram *pProgram;  /* Used when p4type is P4_SUBPROGRAM */
+    Table *pTab;           /* Used when p4type is P4_TABLE */
+    SubrtnSig *pSubrtnSig; /* Used when p4type is P4_SUBRTNSIG */
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+    Expr *pExpr;           /* Used when p4type is P4_EXPR */
+#endif
+  } p4;
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  char *zComment;          /* Comment to improve readability */
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  u32 iSrcLine;            /* Source-code line that generated this opcode
+                           ** with flags in the upper 8 bits */
+#endif
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
+  u64 nExec;
+  u64 nCycle;
+#endif
+};
+typedef struct VdbeOp VdbeOp;
+
+
+/*
+** A sub-routine used to implement a trigger program.
+*/
+struct SubProgram {
+  VdbeOp *aOp;                  /* Array of opcodes for sub-program */
+  int nOp;                      /* Elements in aOp[] */
+  int nMem;                     /* Number of memory cells required */
+  int nCsr;                     /* Number of cursors required */
+  u8 *aOnce;                    /* Array of OP_Once flags */
+  void *token;                  /* id that may be used to recursive triggers */
+  SubProgram *pNext;            /* Next sub-program already visited */
+};
+
+/*
+** A smaller version of VdbeOp used for the VdbeAddOpList() function because
+** it takes up less space.
+*/
+struct VdbeOpList {
+  u8 opcode;          /* What operation to perform */
+  signed char p1;     /* First operand */
+  signed char p2;     /* Second parameter (often the jump destination) */
+  signed char p3;     /* Third parameter */
+};
+typedef struct VdbeOpList VdbeOpList;
+
+/*
+** Allowed values of VdbeOp.p4type
+*/
+#define P4_NOTUSED      0   /* The P4 parameter is not used */
+#define P4_TRANSIENT    0   /* P4 is a pointer to a transient string */
+#define P4_STATIC     (-1)  /* Pointer to a static string */
+#define P4_COLLSEQ    (-2)  /* P4 is a pointer to a CollSeq structure */
+#define P4_INT32      (-3)  /* P4 is a 32-bit signed integer */
+#define P4_SUBPROGRAM (-4)  /* P4 is a pointer to a SubProgram structure */
+#define P4_TABLE      (-5)  /* P4 is a pointer to a Table structure */
+/* Above do not own any resources.  Must free those below */
+#define P4_FREE_IF_LE (-6)
+#define P4_DYNAMIC    (-6)  /* Pointer to memory from sqliteMalloc() */
+#define P4_FUNCDEF    (-7)  /* P4 is a pointer to a FuncDef structure */
+#define P4_KEYINFO    (-8)  /* P4 is a pointer to a KeyInfo structure */
+#define P4_EXPR       (-9) /* P4 is a pointer to an Expr tree */
+#define P4_MEM        (-10) /* P4 is a pointer to a Mem*    structure */
+#define P4_VTAB       (-11) /* P4 is a pointer to an sqlite3_vtab structure */
+#define P4_REAL       (-12) /* P4 is a 64-bit floating point value */
+#define P4_INT64      (-13) /* P4 is a 64-bit signed integer */
+#define P4_INTARRAY   (-14) /* P4 is a vector of 32-bit integers */
+#define P4_FUNCCTX    (-15) /* P4 is a pointer to an sqlite3_context object */
+#define P4_TABLEREF   (-16) /* Like P4_TABLE, but reference counted */
+#define P4_SUBRTNSIG  (-17) /* P4 is a SubrtnSig pointer */
+
+/* Error message codes for OP_Halt */
+#define P5_ConstraintNotNull 1
+#define P5_ConstraintUnique  2
+#define P5_ConstraintCheck   3
+#define P5_ConstraintFK      4
+
+/*
+** The Vdbe.aColName array contains 5n Mem structures, where n is the
+** number of columns of data returned by the statement.
+*/
+#define COLNAME_NAME     0
+#define COLNAME_DECLTYPE 1
+#define COLNAME_DATABASE 2
+#define COLNAME_TABLE    3
+#define COLNAME_COLUMN   4
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+# define COLNAME_N        5      /* Number of COLNAME_xxx symbols */
+#else
+# ifdef SQLITE_OMIT_DECLTYPE
+#   define COLNAME_N      1      /* Store only the name */
+# else
+#   define COLNAME_N      2      /* Store the name and decltype */
+# endif
+#endif
+
+/*
+** The following macro converts a label returned by sqlite3VdbeMakeLabel()
+** into an index into the Parse.aLabel[] array that contains the resolved
+** address of that label.
+*/
+#define ADDR(X)  (~(X))
+
+/*
+** The makefile scans the vdbe.c source file and creates the "opcodes.h"
+** header file that defines a number for each opcode used by the VDBE.
+*/
+/************** Include opcodes.h in the middle of vdbe.h ********************/
+/************** Begin file opcodes.h *****************************************/
+/* Automatically generated.  Do not edit */
+/* See the tool/mkopcodeh.tcl script for details */
+#define OP_Savepoint       0
+#define OP_AutoCommit      1
+#define OP_Transaction     2
+#define OP_Checkpoint      3
+#define OP_JournalMode     4
+#define OP_Vacuum          5
+#define OP_VFilter         6 /* jump, synopsis: iplan=r[P3] zplan='P4'     */
+#define OP_VUpdate         7 /* synopsis: data=r[P3@P2]                    */
+#define OP_Init            8 /* jump0, synopsis: Start at P2               */
+#define OP_Goto            9 /* jump                                       */
+#define OP_Gosub          10 /* jump                                       */
+#define OP_InitCoroutine  11 /* jump0                                      */
+#define OP_Yield          12 /* jump0                                      */
+#define OP_MustBeInt      13 /* jump0                                      */
+#define OP_Jump           14 /* jump                                       */
+#define OP_Once           15 /* jump                                       */
+#define OP_If             16 /* jump                                       */
+#define OP_IfNot          17 /* jump                                       */
+#define OP_IsType         18 /* jump, synopsis: if typeof(P1.P3) in P5 goto P2 */
+#define OP_Not            19 /* same as TK_NOT, synopsis: r[P2]= !r[P1]    */
+#define OP_IfNullRow      20 /* jump, synopsis: if P1.nullRow then r[P3]=NULL, goto P2 */
+#define OP_SeekLT         21 /* jump0, synopsis: key=r[P3@P4]              */
+#define OP_SeekLE         22 /* jump0, synopsis: key=r[P3@P4]              */
+#define OP_SeekGE         23 /* jump0, synopsis: key=r[P3@P4]              */
+#define OP_SeekGT         24 /* jump0, synopsis: key=r[P3@P4]              */
+#define OP_IfNotOpen      25 /* jump, synopsis: if( !csr[P1] ) goto P2     */
+#define OP_IfNoHope       26 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_NoConflict     27 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_NotFound       28 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_Found          29 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_SeekRowid      30 /* jump0, synopsis: intkey=r[P3]              */
+#define OP_NotExists      31 /* jump, synopsis: intkey=r[P3]               */
+#define OP_Last           32 /* jump0                                      */
+#define OP_IfSizeBetween  33 /* jump                                       */
+#define OP_SorterSort     34 /* jump                                       */
+#define OP_Sort           35 /* jump                                       */
+#define OP_Rewind         36 /* jump0                                      */
+#define OP_SorterNext     37 /* jump                                       */
+#define OP_Prev           38 /* jump                                       */
+#define OP_Next           39 /* jump                                       */
+#define OP_IdxLE          40 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_IdxGT          41 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_IdxLT          42 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_Or             43 /* same as TK_OR, synopsis: r[P3]=(r[P1] || r[P2]) */
+#define OP_And            44 /* same as TK_AND, synopsis: r[P3]=(r[P1] && r[P2]) */
+#define OP_IdxGE          45 /* jump, synopsis: key=r[P3@P4]               */
+#define OP_RowSetRead     46 /* jump, synopsis: r[P3]=rowset(P1)           */
+#define OP_RowSetTest     47 /* jump, synopsis: if r[P3] in rowset(P1) goto P2 */
+#define OP_Program        48 /* jump0                                      */
+#define OP_FkIfZero       49 /* jump, synopsis: if fkctr[P1]==0 goto P2    */
+#define OP_IfPos          50 /* jump, synopsis: if r[P1]>0 then r[P1]-=P3, goto P2 */
+#define OP_IsNull         51 /* jump, same as TK_ISNULL, synopsis: if r[P1]==NULL goto P2 */
+#define OP_NotNull        52 /* jump, same as TK_NOTNULL, synopsis: if r[P1]!=NULL goto P2 */
+#define OP_Ne             53 /* jump, same as TK_NE, synopsis: IF r[P3]!=r[P1] */
+#define OP_Eq             54 /* jump, same as TK_EQ, synopsis: IF r[P3]==r[P1] */
+#define OP_Gt             55 /* jump, same as TK_GT, synopsis: IF r[P3]>r[P1] */
+#define OP_Le             56 /* jump, same as TK_LE, synopsis: IF r[P3]<=r[P1] */
+#define OP_Lt             57 /* jump, same as TK_LT, synopsis: IF r[P3]<r[P1] */
+#define OP_Ge             58 /* jump, same as TK_GE, synopsis: IF r[P3]>=r[P1] */
+#define OP_ElseEq         59 /* jump, same as TK_ESCAPE                    */
+#define OP_IfNotZero      60 /* jump, synopsis: if r[P1]!=0 then r[P1]--, goto P2 */
+#define OP_DecrJumpZero   61 /* jump, synopsis: if (--r[P1])==0 goto P2    */
+#define OP_IncrVacuum     62 /* jump                                       */
+#define OP_VNext          63 /* jump                                       */
+#define OP_Filter         64 /* jump, synopsis: if key(P3@P4) not in filter(P1) goto P2 */
+#define OP_PureFunc       65 /* synopsis: r[P3]=func(r[P2@NP])             */
+#define OP_Function       66 /* synopsis: r[P3]=func(r[P2@NP])             */
+#define OP_Return         67
+#define OP_EndCoroutine   68
+#define OP_HaltIfNull     69 /* synopsis: if r[P3]=null halt               */
+#define OP_Halt           70
+#define OP_Integer        71 /* synopsis: r[P2]=P1                         */
+#define OP_Int64          72 /* synopsis: r[P2]=P4                         */
+#define OP_String         73 /* synopsis: r[P2]='P4' (len=P1)              */
+#define OP_BeginSubrtn    74 /* synopsis: r[P2]=NULL                       */
+#define OP_Null           75 /* synopsis: r[P2..P3]=NULL                   */
+#define OP_SoftNull       76 /* synopsis: r[P1]=NULL                       */
+#define OP_Blob           77 /* synopsis: r[P2]=P4 (len=P1)                */
+#define OP_Variable       78 /* synopsis: r[P2]=parameter(P1)              */
+#define OP_Move           79 /* synopsis: r[P2@P3]=r[P1@P3]                */
+#define OP_Copy           80 /* synopsis: r[P2@P3+1]=r[P1@P3+1]            */
+#define OP_SCopy          81 /* synopsis: r[P2]=r[P1]                      */
+#define OP_IntCopy        82 /* synopsis: r[P2]=r[P1]                      */
+#define OP_FkCheck        83
+#define OP_ResultRow      84 /* synopsis: output=r[P1@P2]                  */
+#define OP_CollSeq        85
+#define OP_AddImm         86 /* synopsis: r[P1]=r[P1]+P2                   */
+#define OP_RealAffinity   87
+#define OP_Cast           88 /* synopsis: affinity(r[P1])                  */
+#define OP_Permutation    89
+#define OP_Compare        90 /* synopsis: r[P1@P3] <-> r[P2@P3]            */
+#define OP_IsTrue         91 /* synopsis: r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4 */
+#define OP_ZeroOrNull     92 /* synopsis: r[P2] = 0 OR NULL                */
+#define OP_Offset         93 /* synopsis: r[P3] = sqlite_offset(P1)        */
+#define OP_Column         94 /* synopsis: r[P3]=PX cursor P1 column P2     */
+#define OP_TypeCheck      95 /* synopsis: typecheck(r[P1@P2])              */
+#define OP_Affinity       96 /* synopsis: affinity(r[P1@P2])               */
+#define OP_MakeRecord     97 /* synopsis: r[P3]=mkrec(r[P1@P2])            */
+#define OP_Count          98 /* synopsis: r[P2]=count()                    */
+#define OP_ReadCookie     99
+#define OP_SetCookie     100
+#define OP_ReopenIdx     101 /* synopsis: root=P2 iDb=P3                   */
+#define OP_OpenRead      102 /* synopsis: root=P2 iDb=P3                   */
+#define OP_BitAnd        103 /* same as TK_BITAND, synopsis: r[P3]=r[P1]&r[P2] */
+#define OP_BitOr         104 /* same as TK_BITOR, synopsis: r[P3]=r[P1]|r[P2] */
+#define OP_ShiftLeft     105 /* same as TK_LSHIFT, synopsis: r[P3]=r[P2]<<r[P1] */
+#define OP_ShiftRight    106 /* same as TK_RSHIFT, synopsis: r[P3]=r[P2]>>r[P1] */
+#define OP_Add           107 /* same as TK_PLUS, synopsis: r[P3]=r[P1]+r[P2] */
+#define OP_Subtract      108 /* same as TK_MINUS, synopsis: r[P3]=r[P2]-r[P1] */
+#define OP_Multiply      109 /* same as TK_STAR, synopsis: r[P3]=r[P1]*r[P2] */
+#define OP_Divide        110 /* same as TK_SLASH, synopsis: r[P3]=r[P2]/r[P1] */
+#define OP_Remainder     111 /* same as TK_REM, synopsis: r[P3]=r[P2]%r[P1] */
+#define OP_Concat        112 /* same as TK_CONCAT, synopsis: r[P3]=r[P2]+r[P1] */
+#define OP_OpenWrite     113 /* synopsis: root=P2 iDb=P3                   */
+#define OP_OpenDup       114
+#define OP_BitNot        115 /* same as TK_BITNOT, synopsis: r[P2]= ~r[P1] */
+#define OP_OpenAutoindex 116 /* synopsis: nColumn=P2                       */
+#define OP_OpenEphemeral 117 /* synopsis: nColumn=P2                       */
+#define OP_String8       118 /* same as TK_STRING, synopsis: r[P2]='P4'    */
+#define OP_SorterOpen    119
+#define OP_SequenceTest  120 /* synopsis: if( cursor[P1].ctr++ ) pc = P2   */
+#define OP_OpenPseudo    121 /* synopsis: P3 columns in r[P2]              */
+#define OP_Close         122
+#define OP_ColumnsUsed   123
+#define OP_SeekScan      124 /* synopsis: Scan-ahead up to P1 rows         */
+#define OP_SeekHit       125 /* synopsis: set P2<=seekHit<=P3              */
+#define OP_Sequence      126 /* synopsis: r[P2]=cursor[P1].ctr++           */
+#define OP_NewRowid      127 /* synopsis: r[P2]=rowid                      */
+#define OP_Insert        128 /* synopsis: intkey=r[P3] data=r[P2]          */
+#define OP_RowCell       129
+#define OP_Delete        130
+#define OP_ResetCount    131
+#define OP_SorterCompare 132 /* synopsis: if key(P1)!=trim(r[P3],P4) goto P2 */
+#define OP_SorterData    133 /* synopsis: r[P2]=data                       */
+#define OP_RowData       134 /* synopsis: r[P2]=data                       */
+#define OP_Rowid         135 /* synopsis: r[P2]=PX rowid of P1             */
+#define OP_NullRow       136
+#define OP_SeekEnd       137
+#define OP_IdxInsert     138 /* synopsis: key=r[P2]                        */
+#define OP_SorterInsert  139 /* synopsis: key=r[P2]                        */
+#define OP_IdxDelete     140 /* synopsis: key=r[P2@P3]                     */
+#define OP_DeferredSeek  141 /* synopsis: Move P3 to P1.rowid if needed    */
+#define OP_IdxRowid      142 /* synopsis: r[P2]=rowid                      */
+#define OP_FinishSeek    143
+#define OP_Destroy       144
+#define OP_Clear         145
+#define OP_ResetSorter   146
+#define OP_CreateBtree   147 /* synopsis: r[P2]=root iDb=P1 flags=P3       */
+#define OP_SqlExec       148
+#define OP_ParseSchema   149
+#define OP_LoadAnalysis  150
+#define OP_DropTable     151
+#define OP_DropIndex     152
+#define OP_DropTrigger   153
+#define OP_Real          154 /* same as TK_FLOAT, synopsis: r[P2]=P4       */
+#define OP_IntegrityCk   155
+#define OP_RowSetAdd     156 /* synopsis: rowset(P1)=r[P2]                 */
+#define OP_Param         157
+#define OP_FkCounter     158 /* synopsis: fkctr[P1]+=P2                    */
+#define OP_MemMax        159 /* synopsis: r[P1]=max(r[P1],r[P2])           */
+#define OP_OffsetLimit   160 /* synopsis: if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1) */
+#define OP_AggInverse    161 /* synopsis: accum=r[P3] inverse(r[P2@P5])    */
+#define OP_AggStep       162 /* synopsis: accum=r[P3] step(r[P2@P5])       */
+#define OP_AggStep1      163 /* synopsis: accum=r[P3] step(r[P2@P5])       */
+#define OP_AggValue      164 /* synopsis: r[P3]=value N=P2                 */
+#define OP_AggFinal      165 /* synopsis: accum=r[P1] N=P2                 */
+#define OP_Expire        166
+#define OP_CursorLock    167
+#define OP_CursorUnlock  168
+#define OP_TableLock     169 /* synopsis: iDb=P1 root=P2 write=P3          */
+#define OP_VBegin        170
+#define OP_VCreate       171
+#define OP_VDestroy      172
+#define OP_VOpen         173
+#define OP_VCheck        174
+#define OP_VInitIn       175 /* synopsis: r[P2]=ValueList(P1,P3)           */
+#define OP_VColumn       176 /* synopsis: r[P3]=vcolumn(P2)                */
+#define OP_VRename       177
+#define OP_Pagecount     178
+#define OP_MaxPgcnt      179
+#define OP_ClrSubtype    180 /* synopsis: r[P1].subtype = 0                */
+#define OP_GetSubtype    181 /* synopsis: r[P2] = r[P1].subtype            */
+#define OP_SetSubtype    182 /* synopsis: r[P2].subtype = r[P1]            */
+#define OP_FilterAdd     183 /* synopsis: filter(P1) += key(P3@P4)         */
+#define OP_Trace         184
+#define OP_CursorHint    185
+#define OP_ReleaseReg    186 /* synopsis: release r[P1@P2] mask P3         */
+#define OP_Noop          187
+#define OP_Explain       188
+#define OP_Abortable     189
+
+/* Properties such as "out2" or "jump" that are specified in
+** comments following the "case" for each opcode in the vdbe.c
+** are encoded into bitvectors as follows:
+*/
+#define OPFLG_JUMP        0x01  /* jump:  P2 holds jmp target */
+#define OPFLG_IN1         0x02  /* in1:   P1 is an input */
+#define OPFLG_IN2         0x04  /* in2:   P2 is an input */
+#define OPFLG_IN3         0x08  /* in3:   P3 is an input */
+#define OPFLG_OUT2        0x10  /* out2:  P2 is an output */
+#define OPFLG_OUT3        0x20  /* out3:  P3 is an output */
+#define OPFLG_NCYCLE      0x40  /* ncycle:Cycles count against P1 */
+#define OPFLG_JUMP0       0x80  /* jump0:  P2 might be zero */
+#define OPFLG_INITIALIZER {\
+/*   0 */ 0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0x41, 0x00,\
+/*   8 */ 0x81, 0x01, 0x01, 0x81, 0x83, 0x83, 0x01, 0x01,\
+/*  16 */ 0x03, 0x03, 0x01, 0x12, 0x01, 0xc9, 0xc9, 0xc9,\
+/*  24 */ 0xc9, 0x01, 0x49, 0x49, 0x49, 0x49, 0xc9, 0x49,\
+/*  32 */ 0xc1, 0x01, 0x41, 0x41, 0xc1, 0x01, 0x41, 0x41,\
+/*  40 */ 0x41, 0x41, 0x41, 0x26, 0x26, 0x41, 0x23, 0x0b,\
+/*  48 */ 0x81, 0x01, 0x03, 0x03, 0x03, 0x0b, 0x0b, 0x0b,\
+/*  56 */ 0x0b, 0x0b, 0x0b, 0x01, 0x03, 0x03, 0x01, 0x41,\
+/*  64 */ 0x01, 0x00, 0x00, 0x02, 0x02, 0x08, 0x00, 0x10,\
+/*  72 */ 0x10, 0x10, 0x00, 0x10, 0x00, 0x10, 0x10, 0x00,\
+/*  80 */ 0x00, 0x10, 0x10, 0x00, 0x00, 0x00, 0x02, 0x02,\
+/*  88 */ 0x02, 0x00, 0x00, 0x12, 0x1e, 0x20, 0x40, 0x00,\
+/*  96 */ 0x00, 0x00, 0x10, 0x10, 0x00, 0x40, 0x40, 0x26,\
+/* 104 */ 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x26,\
+/* 112 */ 0x26, 0x00, 0x40, 0x12, 0x40, 0x40, 0x10, 0x00,\
+/* 120 */ 0x00, 0x00, 0x40, 0x00, 0x40, 0x40, 0x10, 0x10,\
+/* 128 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x50,\
+/* 136 */ 0x00, 0x40, 0x04, 0x04, 0x00, 0x40, 0x50, 0x40,\
+/* 144 */ 0x10, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00,\
+/* 152 */ 0x00, 0x00, 0x10, 0x00, 0x06, 0x10, 0x00, 0x04,\
+/* 160 */ 0x1a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
+/* 168 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x10, 0x50,\
+/* 176 */ 0x40, 0x00, 0x10, 0x10, 0x02, 0x12, 0x12, 0x00,\
+/* 184 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,}
+
+/* The resolve3P2Values() routine is able to run faster if it knows
+** the value of the largest JUMP opcode.  The smaller the maximum
+** JUMP opcode the better, so the mkopcodeh.tcl script that
+** generated this include file strives to group all JUMP opcodes
+** together near the beginning of the list.
+*/
+#define SQLITE_MX_JUMP_OPCODE  64  /* Maximum JUMP opcode */
+
+/************** End of opcodes.h *********************************************/
+/************** Continuing where we left off in vdbe.h ***********************/
+
+/*
+** Additional non-public SQLITE_PREPARE_* flags
+*/
+#define SQLITE_PREPARE_SAVESQL  0x80  /* Preserve SQL text */
+#define SQLITE_PREPARE_MASK     0x1f  /* Mask of public flags */
+
+/*
+** Prototypes for the VDBE interface.  See comments on the implementation
+** for a description of what each of these routines does.
+*/
+SQLITE_PRIVATE Vdbe *sqlite3VdbeCreate(Parse*);
+SQLITE_PRIVATE Parse *sqlite3VdbeParser(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeAddOp0(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp1(Vdbe*,int,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp2(Vdbe*,int,int,int);
+SQLITE_PRIVATE int sqlite3VdbeGoto(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeLoadString(Vdbe*,int,const char*);
+SQLITE_PRIVATE void sqlite3VdbeMultiLoad(Vdbe*,int,const char*,...);
+SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp4(Vdbe*,int,int,int,int,const char *zP4,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Dup8(Vdbe*,int,int,int,int,const u8*,int);
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Int(Vdbe*,int,int,int,int,int);
+SQLITE_PRIVATE int sqlite3VdbeAddFunctionCall(Parse*,int,int,int,int,const FuncDef*,int);
+SQLITE_PRIVATE void sqlite3VdbeEndCoroutine(Vdbe*,int);
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_TEST_REALLOC_STRESS)
+SQLITE_PRIVATE   void sqlite3VdbeVerifyNoMallocRequired(Vdbe *p, int N);
+SQLITE_PRIVATE   void sqlite3VdbeVerifyNoResultRow(Vdbe *p);
+#else
+# define sqlite3VdbeVerifyNoMallocRequired(A,B)
+# define sqlite3VdbeVerifyNoResultRow(A)
+#endif
+#if defined(SQLITE_DEBUG)
+SQLITE_PRIVATE   void sqlite3VdbeVerifyAbortable(Vdbe *p, int);
+SQLITE_PRIVATE   void sqlite3VdbeNoJumpsOutsideSubrtn(Vdbe*,int,int,int);
+#else
+# define sqlite3VdbeVerifyAbortable(A,B)
+# define sqlite3VdbeNoJumpsOutsideSubrtn(A,B,C,D)
+#endif
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp,int iLineno);
+#ifndef SQLITE_OMIT_EXPLAIN
+SQLITE_PRIVATE   int sqlite3VdbeExplain(Parse*,u8,const char*,...);
+SQLITE_PRIVATE   void sqlite3VdbeExplainPop(Parse*);
+SQLITE_PRIVATE   int sqlite3VdbeExplainParent(Parse*);
+# define ExplainQueryPlan(P)        sqlite3VdbeExplain P
+# ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+#  define ExplainQueryPlan2(V,P)     (V = sqlite3VdbeExplain P)
+# else
+#  define ExplainQueryPlan2(V,P)     ExplainQueryPlan(P)
+# endif
+# define ExplainQueryPlanPop(P)     sqlite3VdbeExplainPop(P)
+# define ExplainQueryPlanParent(P)  sqlite3VdbeExplainParent(P)
+#else
+# define ExplainQueryPlan(P)
+# define ExplainQueryPlan2(V,P)
+# define ExplainQueryPlanPop(P)
+# define ExplainQueryPlanParent(P) 0
+# define sqlite3ExplainBreakpoint(A,B) /*no-op*/
+#endif
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_EXPLAIN)
+SQLITE_PRIVATE   void sqlite3ExplainBreakpoint(const char*,const char*);
+#else
+# define sqlite3ExplainBreakpoint(A,B) /*no-op*/
+#endif
+SQLITE_PRIVATE void sqlite3VdbeAddParseSchemaOp(Vdbe*, int, char*, u16);
+SQLITE_PRIVATE void sqlite3VdbeChangeOpcode(Vdbe*, int addr, u8);
+SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
+SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
+SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe*, int addr, int P3);
+SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe*, u16 P5);
+SQLITE_PRIVATE void sqlite3VdbeTypeofColumn(Vdbe*, int);
+SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe*, int addr);
+SQLITE_PRIVATE void sqlite3VdbeJumpHereOrPopInst(Vdbe*, int addr);
+SQLITE_PRIVATE int sqlite3VdbeChangeToNoop(Vdbe*, int addr);
+SQLITE_PRIVATE int sqlite3VdbeDeletePriorOpcode(Vdbe*, u8 op);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3VdbeReleaseRegisters(Parse*,int addr, int n, u32 mask, int);
+#else
+# define sqlite3VdbeReleaseRegisters(P,A,N,M,F)
+#endif
+SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
+SQLITE_PRIVATE void sqlite3VdbeAppendP4(Vdbe*, void *pP4, int p4type);
+SQLITE_PRIVATE void sqlite3VdbeSetP4KeyInfo(Parse*, Index*);
+SQLITE_PRIVATE void sqlite3VdbeUsesBtree(Vdbe*, int);
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetLastOp(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeMakeLabel(Parse*);
+SQLITE_PRIVATE void sqlite3VdbeRunOnlyOnce(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeReusable(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeMakeReady(Vdbe*,Parse*);
+SQLITE_PRIVATE int sqlite3VdbeFinalize(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe*, int);
+SQLITE_PRIVATE int sqlite3VdbeCurrentAddr(Vdbe*);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   int sqlite3VdbeAssertMayAbort(Vdbe *, int);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeResetStepResult(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeRewind(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeReset(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe*,int);
+SQLITE_PRIVATE int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, void(*)(void*));
+SQLITE_PRIVATE void sqlite3VdbeCountChanges(Vdbe*);
+SQLITE_PRIVATE sqlite3 *sqlite3VdbeDb(Vdbe*);
+SQLITE_PRIVATE u8 sqlite3VdbePrepareFlags(Vdbe*);
+SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe*, const char *z, int n, u8);
+#ifdef SQLITE_ENABLE_NORMALIZE
+SQLITE_PRIVATE void sqlite3VdbeAddDblquoteStr(sqlite3*,Vdbe*,const char*);
+SQLITE_PRIVATE int sqlite3VdbeUsesDoubleQuotedString(Vdbe*,const char*);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe*,Vdbe*);
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeTakeOpArray(Vdbe*, int*, int*);
+SQLITE_PRIVATE sqlite3_value *sqlite3VdbeGetBoundValue(Vdbe*, int, u8);
+SQLITE_PRIVATE void sqlite3VdbeSetVarmask(Vdbe*, int);
+#ifndef SQLITE_OMIT_TRACE
+SQLITE_PRIVATE   char *sqlite3VdbeExpandSql(Vdbe*, const char*);
+#endif
+SQLITE_PRIVATE int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
+SQLITE_PRIVATE int sqlite3BlobCompare(const Mem*, const Mem*);
+
+SQLITE_PRIVATE void sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,UnpackedRecord*);
+SQLITE_PRIVATE int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);
+SQLITE_PRIVATE int sqlite3VdbeRecordCompareWithSkip(int, const void *, UnpackedRecord *, int);
+SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(KeyInfo*);
+
+typedef int (*RecordCompare)(int,const void*,UnpackedRecord*);
+SQLITE_PRIVATE RecordCompare sqlite3VdbeFindCompare(UnpackedRecord*);
+
+SQLITE_PRIVATE void sqlite3VdbeLinkSubProgram(Vdbe *, SubProgram *);
+SQLITE_PRIVATE int sqlite3VdbeHasSubProgram(Vdbe*);
+
+SQLITE_PRIVATE void sqlite3MemSetArrayInt64(sqlite3_value *aMem, int iIdx, i64 val);
+
+SQLITE_PRIVATE int sqlite3NotPureFunc(sqlite3_context*);
+#ifdef SQLITE_ENABLE_BYTECODE_VTAB
+SQLITE_PRIVATE int sqlite3VdbeBytecodeVtabInit(sqlite3*);
+#endif
+
+/* Use SQLITE_ENABLE_COMMENTS to enable generation of extra comments on
+** each VDBE opcode.
+**
+** Use the SQLITE_ENABLE_MODULE_COMMENTS macro to see some extra no-op
+** comments in VDBE programs that show key decision points in the code
+** generator.
+*/
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+SQLITE_PRIVATE   void sqlite3VdbeComment(Vdbe*, const char*, ...);
+# define VdbeComment(X)  sqlite3VdbeComment X
+SQLITE_PRIVATE   void sqlite3VdbeNoopComment(Vdbe*, const char*, ...);
+# define VdbeNoopComment(X)  sqlite3VdbeNoopComment X
+# ifdef SQLITE_ENABLE_MODULE_COMMENTS
+#   define VdbeModuleComment(X)  sqlite3VdbeNoopComment X
+# else
+#   define VdbeModuleComment(X)
+# endif
+#else
+# define VdbeComment(X)
+# define VdbeNoopComment(X)
+# define VdbeModuleComment(X)
+#endif
+
+/*
+** The VdbeCoverage macros are used to set a coverage testing point
+** for VDBE branch instructions.  The coverage testing points are line
+** numbers in the sqlite3.c source file.  VDBE branch coverage testing
+** only works with an amalgamation build.  That's ok since a VDBE branch
+** coverage build designed for testing the test suite only.  No application
+** should ever ship with VDBE branch coverage measuring turned on.
+**
+**    VdbeCoverage(v)                  // Mark the previously coded instruction
+**                                     // as a branch
+**
+**    VdbeCoverageIf(v, conditional)   // Mark previous if conditional true
+**
+**    VdbeCoverageAlwaysTaken(v)       // Previous branch is always taken
+**
+**    VdbeCoverageNeverTaken(v)        // Previous branch is never taken
+**
+**    VdbeCoverageNeverNull(v)         // Previous three-way branch is only
+**                                     // taken on the first two ways.  The
+**                                     // NULL option is not possible
+**
+**    VdbeCoverageEqNe(v)              // Previous OP_Jump is only interested
+**                                     // in distinguishing equal and not-equal.
+**
+** Every VDBE branch operation must be tagged with one of the macros above.
+** If not, then when "make test" is run with -DSQLITE_VDBE_COVERAGE and
+** -DSQLITE_DEBUG then an ALWAYS() will fail in the vdbeTakeBranch()
+** routine in vdbe.c, alerting the developer to the missed tag.
+**
+** During testing, the test application will invoke
+** sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE,...) to set a callback
+** routine that is invoked as each bytecode branch is taken.  The callback
+** contains the sqlite3.c source line number of the VdbeCoverage macro and
+** flags to indicate whether or not the branch was taken.  The test application
+** is responsible for keeping track of this and reporting byte-code branches
+** that are never taken.
+**
+** See the VdbeBranchTaken() macro and vdbeTakeBranch() function in the
+** vdbe.c source file for additional information.
+*/
+#ifdef SQLITE_VDBE_COVERAGE
+SQLITE_PRIVATE   void sqlite3VdbeSetLineNumber(Vdbe*,int);
+# define VdbeCoverage(v) sqlite3VdbeSetLineNumber(v,__LINE__)
+# define VdbeCoverageIf(v,x) if(x)sqlite3VdbeSetLineNumber(v,__LINE__)
+# define VdbeCoverageAlwaysTaken(v) \
+         sqlite3VdbeSetLineNumber(v,__LINE__|0x5000000);
+# define VdbeCoverageNeverTaken(v) \
+         sqlite3VdbeSetLineNumber(v,__LINE__|0x6000000);
+# define VdbeCoverageNeverNull(v) \
+         sqlite3VdbeSetLineNumber(v,__LINE__|0x4000000);
+# define VdbeCoverageNeverNullIf(v,x) \
+         if(x)sqlite3VdbeSetLineNumber(v,__LINE__|0x4000000);
+# define VdbeCoverageEqNe(v) \
+         sqlite3VdbeSetLineNumber(v,__LINE__|0x8000000);
+# define VDBE_OFFSET_LINENO(x) (__LINE__+x)
+#else
+# define VdbeCoverage(v)
+# define VdbeCoverageIf(v,x)
+# define VdbeCoverageAlwaysTaken(v)
+# define VdbeCoverageNeverTaken(v)
+# define VdbeCoverageNeverNull(v)
+# define VdbeCoverageNeverNullIf(v,x)
+# define VdbeCoverageEqNe(v)
+# define VDBE_OFFSET_LINENO(x) 0
+#endif
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+SQLITE_PRIVATE void sqlite3VdbeScanStatus(Vdbe*, int, int, int, LogEst, const char*);
+SQLITE_PRIVATE void sqlite3VdbeScanStatusRange(Vdbe*, int, int, int);
+SQLITE_PRIVATE void sqlite3VdbeScanStatusCounters(Vdbe*, int, int, int);
+#else
+# define sqlite3VdbeScanStatus(a,b,c,d,e,f)
+# define sqlite3VdbeScanStatusRange(a,b,c,d)
+# define sqlite3VdbeScanStatusCounters(a,b,c,d)
+#endif
+
+#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
+SQLITE_PRIVATE void sqlite3VdbePrintOp(FILE*, int, VdbeOp*);
+#endif
+
+#if defined(SQLITE_ENABLE_CURSOR_HINTS) && defined(SQLITE_DEBUG)
+SQLITE_PRIVATE int sqlite3CursorRangeHintExprCheck(Walker *pWalker, Expr *pExpr);
+#endif
+
+#endif /* SQLITE_VDBE_H */
+
+/************** End of vdbe.h ************************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include pcache.h in the middle of sqliteInt.h ****************/
+/************** Begin file pcache.h ******************************************/
+/*
+** 2008 August 05
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the sqlite page cache
+** subsystem.
+*/
+
+#ifndef _PCACHE_H_
+
+typedef struct PgHdr PgHdr;
+typedef struct PCache PCache;
+
+/*
+** Every page in the cache is controlled by an instance of the following
+** structure.
+*/
+struct PgHdr {
+  sqlite3_pcache_page *pPage;    /* Pcache object page handle */
+  void *pData;                   /* Page data */
+  void *pExtra;                  /* Extra content */
+  PCache *pCache;                /* PRIVATE: Cache that owns this page */
+  PgHdr *pDirty;                 /* Transient list of dirty sorted by pgno */
+  Pager *pPager;                 /* The pager this page is part of */
+  Pgno pgno;                     /* Page number for this page */
+#ifdef SQLITE_CHECK_PAGES
+  u32 pageHash;                  /* Hash of page content */
+#endif
+  u16 flags;                     /* PGHDR flags defined below */
+
+  /**********************************************************************
+  ** Elements above, except pCache, are public.  All that follow are
+  ** private to pcache.c and should not be accessed by other modules.
+  ** pCache is grouped with the public elements for efficiency.
+  */
+  i64 nRef;                      /* Number of users of this page */
+  PgHdr *pDirtyNext;             /* Next element in list of dirty pages */
+  PgHdr *pDirtyPrev;             /* Previous element in list of dirty pages */
+                          /* NB: pDirtyNext and pDirtyPrev are undefined if the
+                          ** PgHdr object is not dirty */
+};
+
+/* Bit values for PgHdr.flags */
+#define PGHDR_CLEAN           0x001  /* Page not on the PCache.pDirty list */
+#define PGHDR_DIRTY           0x002  /* Page is on the PCache.pDirty list */
+#define PGHDR_WRITEABLE       0x004  /* Journaled and ready to modify */
+#define PGHDR_NEED_SYNC       0x008  /* Fsync the rollback journal before
+                                     ** writing this page to the database */
+#define PGHDR_DONT_WRITE      0x010  /* Do not write content to disk */
+#define PGHDR_MMAP            0x020  /* This is an mmap page object */
+
+#define PGHDR_WAL_APPEND      0x040  /* Appended to wal file */
+
+/* Initialize and shutdown the page cache subsystem */
+SQLITE_PRIVATE int sqlite3PcacheInitialize(void);
+SQLITE_PRIVATE void sqlite3PcacheShutdown(void);
+
+/* Page cache buffer management:
+** These routines implement SQLITE_CONFIG_PAGECACHE.
+*/
+SQLITE_PRIVATE void sqlite3PCacheBufferSetup(void *, int sz, int n);
+
+/* Create a new pager cache.
+** Under memory stress, invoke xStress to try to make pages clean.
+** Only clean and unpinned pages can be reclaimed.
+*/
+SQLITE_PRIVATE int sqlite3PcacheOpen(
+  int szPage,                    /* Size of every page */
+  int szExtra,                   /* Extra space associated with each page */
+  int bPurgeable,                /* True if pages are on backing store */
+  int (*xStress)(void*, PgHdr*), /* Call to try to make pages clean */
+  void *pStress,                 /* Argument to xStress */
+  PCache *pToInit                /* Preallocated space for the PCache */
+);
+
+/* Modify the page-size after the cache has been created. */
+SQLITE_PRIVATE int sqlite3PcacheSetPageSize(PCache *, int);
+
+/* Return the size in bytes of a PCache object.  Used to preallocate
+** storage space.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSize(void);
+
+/* One release per successful fetch.  Page is pinned until released.
+** Reference counted.
+*/
+SQLITE_PRIVATE sqlite3_pcache_page *sqlite3PcacheFetch(PCache*, Pgno, int createFlag);
+SQLITE_PRIVATE int sqlite3PcacheFetchStress(PCache*, Pgno, sqlite3_pcache_page**);
+SQLITE_PRIVATE PgHdr *sqlite3PcacheFetchFinish(PCache*, Pgno, sqlite3_pcache_page *pPage);
+SQLITE_PRIVATE void sqlite3PcacheRelease(PgHdr*);
+
+SQLITE_PRIVATE void sqlite3PcacheDrop(PgHdr*);         /* Remove page from cache */
+SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr*);    /* Make sure page is marked dirty */
+SQLITE_PRIVATE void sqlite3PcacheMakeClean(PgHdr*);    /* Mark a single page as clean */
+SQLITE_PRIVATE void sqlite3PcacheCleanAll(PCache*);    /* Mark all dirty list pages as clean */
+SQLITE_PRIVATE void sqlite3PcacheClearWritable(PCache*);
+
+/* Change a page number.  Used by incr-vacuum. */
+SQLITE_PRIVATE void sqlite3PcacheMove(PgHdr*, Pgno);
+
+/* Remove all pages with pgno>x.  Reset the cache if x==0 */
+SQLITE_PRIVATE void sqlite3PcacheTruncate(PCache*, Pgno x);
+
+/* Get a list of all dirty pages in the cache, sorted by page number */
+SQLITE_PRIVATE PgHdr *sqlite3PcacheDirtyList(PCache*);
+
+/* Reset and close the cache object */
+SQLITE_PRIVATE void sqlite3PcacheClose(PCache*);
+
+/* Clear flags from pages of the page cache */
+SQLITE_PRIVATE void sqlite3PcacheClearSyncFlags(PCache *);
+
+/* Discard the contents of the cache */
+SQLITE_PRIVATE void sqlite3PcacheClear(PCache*);
+
+/* Return the total number of outstanding page references */
+SQLITE_PRIVATE i64 sqlite3PcacheRefCount(PCache*);
+
+/* Increment the reference count of an existing page */
+SQLITE_PRIVATE void sqlite3PcacheRef(PgHdr*);
+
+SQLITE_PRIVATE i64 sqlite3PcachePageRefcount(PgHdr*);
+
+/* Return the total number of pages stored in the cache */
+SQLITE_PRIVATE int sqlite3PcachePagecount(PCache*);
+
+#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
+/* Iterate through all dirty pages currently stored in the cache. This
+** interface is only available if SQLITE_CHECK_PAGES is defined when the
+** library is built.
+*/
+SQLITE_PRIVATE void sqlite3PcacheIterateDirty(PCache *pCache, void (*xIter)(PgHdr *));
+#endif
+
+#if defined(SQLITE_DEBUG)
+/* Check invariants on a PgHdr object */
+SQLITE_PRIVATE int sqlite3PcachePageSanity(PgHdr*);
+#endif
+
+/* Set and get the suggested cache-size for the specified pager-cache.
+**
+** If no global maximum is configured, then the system attempts to limit
+** the total number of pages cached by purgeable pager-caches to the sum
+** of the suggested cache-sizes.
+*/
+SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *, int);
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *);
+#endif
+
+/* Set or get the suggested spill-size for the specified pager-cache.
+**
+** The spill-size is the minimum number of pages in cache before the cache
+** will attempt to spill dirty pages by calling xStress.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSetSpillsize(PCache *, int);
+
+/* Free up as much memory as possible from the page cache */
+SQLITE_PRIVATE void sqlite3PcacheShrink(PCache*);
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/* Try to return memory used by the pcache module to the main memory heap */
+SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int);
+#endif
+
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE void sqlite3PcacheStats(int*,int*,int*,int*);
+#endif
+
+SQLITE_PRIVATE void sqlite3PCacheSetDefault(void);
+
+/* Return the header size */
+SQLITE_PRIVATE int sqlite3HeaderSizePcache(void);
+SQLITE_PRIVATE int sqlite3HeaderSizePcache1(void);
+
+/* Number of dirty pages as a percentage of the configured cache size */
+SQLITE_PRIVATE int sqlite3PCachePercentDirty(PCache*);
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+SQLITE_PRIVATE int sqlite3PCacheIsDirty(PCache *pCache);
+#endif
+
+#endif /* _PCACHE_H_ */
+
+/************** End of pcache.h **********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+/************** Include mutex.h in the middle of sqliteInt.h *****************/
+/************** Begin file mutex.h *******************************************/
+/*
+** 2007 August 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the common header for all mutex implementations.
+** The sqliteInt.h header #includes this file so that it is available
+** to all source files.  We break it out in an effort to keep the code
+** better organized.
+**
+** NOTE:  source files should *not* #include this header file directly.
+** Source files should #include the sqliteInt.h file and let that file
+** include this one indirectly.
+*/
+
+
+/*
+** Figure out what version of the code to use.  The choices are
+**
+**   SQLITE_MUTEX_OMIT         No mutex logic.  Not even stubs.  The
+**                             mutexes implementation cannot be overridden
+**                             at start-time.
+**
+**   SQLITE_MUTEX_NOOP         For single-threaded applications.  No
+**                             mutual exclusion is provided.  But this
+**                             implementation can be overridden at
+**                             start-time.
+**
+**   SQLITE_MUTEX_PTHREADS     For multi-threaded applications on Unix.
+**
+**   SQLITE_MUTEX_W32          For multi-threaded applications on Win32.
+*/
+#if !SQLITE_THREADSAFE
+# define SQLITE_MUTEX_OMIT
+#endif
+#if SQLITE_THREADSAFE && !defined(SQLITE_MUTEX_NOOP)
+#  if SQLITE_OS_UNIX
+#    define SQLITE_MUTEX_PTHREADS
+#  elif SQLITE_OS_WIN
+#    define SQLITE_MUTEX_W32
+#  else
+#    define SQLITE_MUTEX_NOOP
+#  endif
+#endif
+
+#ifdef SQLITE_MUTEX_OMIT
+/*
+** If this is a no-op implementation, implement everything as macros.
+*/
+#define sqlite3_mutex_alloc(X)    ((sqlite3_mutex*)8)
+#define sqlite3_mutex_free(X)
+#define sqlite3_mutex_enter(X)
+#define sqlite3_mutex_try(X)      SQLITE_OK
+#define sqlite3_mutex_leave(X)
+#define sqlite3_mutex_held(X)     ((void)(X),1)
+#define sqlite3_mutex_notheld(X)  ((void)(X),1)
+#define sqlite3MutexAlloc(X)      ((sqlite3_mutex*)8)
+#define sqlite3MutexInit()        SQLITE_OK
+#define sqlite3MutexEnd()
+#define MUTEX_LOGIC(X)
+#else
+#define MUTEX_LOGIC(X)            X
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
+#endif /* defined(SQLITE_MUTEX_OMIT) */
+
+/************** End of mutex.h ***********************************************/
+/************** Continuing where we left off in sqliteInt.h ******************/
+
+/* The SQLITE_EXTRA_DURABLE compile-time option used to set the default
+** synchronous setting to EXTRA.  It is no longer supported.
+*/
+#ifdef SQLITE_EXTRA_DURABLE
+# warning Use SQLITE_DEFAULT_SYNCHRONOUS=3 instead of SQLITE_EXTRA_DURABLE
+# define SQLITE_DEFAULT_SYNCHRONOUS 3
+#endif
+
+/*
+** Default synchronous levels.
+**
+** Note that (for historical reasons) the PAGER_SYNCHRONOUS_* macros differ
+** from the SQLITE_DEFAULT_SYNCHRONOUS value by 1.
+**
+**           PAGER_SYNCHRONOUS       DEFAULT_SYNCHRONOUS
+**   OFF           1                         0
+**   NORMAL        2                         1
+**   FULL          3                         2
+**   EXTRA         4                         3
+**
+** The "PRAGMA synchronous" statement also uses the zero-based numbers.
+** In other words, the zero-based numbers are used for all external interfaces
+** and the one-based values are used internally.
+*/
+#ifndef SQLITE_DEFAULT_SYNCHRONOUS
+# define SQLITE_DEFAULT_SYNCHRONOUS 2
+#endif
+#ifndef SQLITE_DEFAULT_WAL_SYNCHRONOUS
+# define SQLITE_DEFAULT_WAL_SYNCHRONOUS SQLITE_DEFAULT_SYNCHRONOUS
+#endif
+
+/*
+** Each database file to be accessed by the system is an instance
+** of the following structure.  There are normally two of these structures
+** in the sqlite.aDb[] array.  aDb[0] is the main database file and
+** aDb[1] is the database file used to hold temporary tables.  Additional
+** databases may be attached.
+*/
+struct Db {
+  char *zDbSName;      /* Name of this database. (schema name, not filename) */
+  Btree *pBt;          /* The B*Tree structure for this database file */
+  u8 safety_level;     /* How aggressive at syncing data to disk */
+  u8 bSyncSet;         /* True if "PRAGMA synchronous=N" has been run */
+  Schema *pSchema;     /* Pointer to database schema (possibly shared) */
+};
+
+/*
+** An instance of the following structure stores a database schema.
+**
+** Most Schema objects are associated with a Btree.  The exception is
+** the Schema for the TEMP database (sqlite3.aDb[1]) which is free-standing.
+** In shared cache mode, a single Schema object can be shared by multiple
+** Btrees that refer to the same underlying BtShared object.
+**
+** Schema objects are automatically deallocated when the last Btree that
+** references them is destroyed.   The TEMP Schema is manually freed by
+** sqlite3_close().
+*
+** A thread must be holding a mutex on the corresponding Btree in order
+** to access Schema content.  This implies that the thread must also be
+** holding a mutex on the sqlite3 connection pointer that owns the Btree.
+** For a TEMP Schema, only the connection mutex is required.
+*/
+struct Schema {
+  int schema_cookie;   /* Database schema version number for this file */
+  int iGeneration;     /* Generation counter.  Incremented with each change */
+  Hash tblHash;        /* All tables indexed by name */
+  Hash idxHash;        /* All (named) indices indexed by name */
+  Hash trigHash;       /* All triggers indexed by name */
+  Hash fkeyHash;       /* All foreign keys by referenced table name */
+  Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
+  u8 file_format;      /* Schema format version for this file */
+  u8 enc;              /* Text encoding used by this database */
+  u16 schemaFlags;     /* Flags associated with this schema */
+  int cache_size;      /* Number of pages to use in the cache */
+};
+
+/*
+** These macros can be used to test, set, or clear bits in the
+** Db.pSchema->flags field.
+*/
+#define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->schemaFlags&(P))==(P))
+#define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].pSchema->schemaFlags&(P))!=0)
+#define DbSetProperty(D,I,P)     (D)->aDb[I].pSchema->schemaFlags|=(P)
+#define DbClearProperty(D,I,P)   (D)->aDb[I].pSchema->schemaFlags&=~(P)
+
+/*
+** Allowed values for the DB.pSchema->flags field.
+**
+** The DB_SchemaLoaded flag is set after the database schema has been
+** read into internal hash tables.
+**
+** DB_UnresetViews means that one or more views have column names that
+** have been filled out.  If the schema changes, these column names might
+** changes and so the view will need to be reset.
+*/
+#define DB_SchemaLoaded    0x0001  /* The schema has been loaded */
+#define DB_UnresetViews    0x0002  /* Some views have defined column names */
+#define DB_ResetWanted     0x0008  /* Reset the schema when nSchemaLock==0 */
+
+/*
+** The number of different kinds of things that can be limited
+** using the sqlite3_limit() interface.
+*/
+#define SQLITE_N_LIMIT (SQLITE_LIMIT_WORKER_THREADS+1)
+
+/*
+** Lookaside malloc is a set of fixed-size buffers that can be used
+** to satisfy small transient memory allocation requests for objects
+** associated with a particular database connection.  The use of
+** lookaside malloc provides a significant performance enhancement
+** (approx 10%) by avoiding numerous malloc/free requests while parsing
+** SQL statements.
+**
+** The Lookaside structure holds configuration information about the
+** lookaside malloc subsystem.  Each available memory allocation in
+** the lookaside subsystem is stored on a linked list of LookasideSlot
+** objects.
+**
+** Lookaside allocations are only allowed for objects that are associated
+** with a particular database connection.  Hence, schema information cannot
+** be stored in lookaside because in shared cache mode the schema information
+** is shared by multiple database connections.  Therefore, while parsing
+** schema information, the Lookaside.bEnabled flag is cleared so that
+** lookaside allocations are not used to construct the schema objects.
+**
+** New lookaside allocations are only allowed if bDisable==0.  When
+** bDisable is greater than zero, sz is set to zero which effectively
+** disables lookaside without adding a new test for the bDisable flag
+** in a performance-critical path.  sz should be set by to szTrue whenever
+** bDisable changes back to zero.
+**
+** Lookaside buffers are initially held on the pInit list.  As they are
+** used and freed, they are added back to the pFree list.  New allocations
+** come off of pFree first, then pInit as a fallback.  This dual-list
+** allows use to compute a high-water mark - the maximum number of allocations
+** outstanding at any point in the past - by subtracting the number of
+** allocations on the pInit list from the total number of allocations.
+**
+** Enhancement on 2019-12-12:  Two-size-lookaside
+** The default lookaside configuration is 100 slots of 1200 bytes each.
+** The larger slot sizes are important for performance, but they waste
+** a lot of space, as most lookaside allocations are less than 128 bytes.
+** The two-size-lookaside enhancement breaks up the lookaside allocation
+** into two pools:  One of 128-byte slots and the other of the default size
+** (1200-byte) slots.   Allocations are filled from the small-pool first,
+** failing over to the full-size pool if that does not work.  Thus more
+** lookaside slots are available while also using less memory.
+** This enhancement can be omitted by compiling with
+** SQLITE_OMIT_TWOSIZE_LOOKASIDE.
+*/
+struct Lookaside {
+  u32 bDisable;           /* Only operate the lookaside when zero */
+  u16 sz;                 /* Size of each buffer in bytes */
+  u16 szTrue;             /* True value of sz, even if disabled */
+  u8 bMalloced;           /* True if pStart obtained from sqlite3_malloc() */
+  u32 nSlot;              /* Number of lookaside slots allocated */
+  u32 anStat[3];          /* 0: hits.  1: size misses.  2: full misses */
+  LookasideSlot *pInit;   /* List of buffers not previously used */
+  LookasideSlot *pFree;   /* List of available buffers */
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  LookasideSlot *pSmallInit; /* List of small buffers not previously used */
+  LookasideSlot *pSmallFree; /* List of available small buffers */
+  void *pMiddle;          /* First byte past end of full-size buffers and
+                          ** the first byte of LOOKASIDE_SMALL buffers */
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+  void *pStart;           /* First byte of available memory space */
+  void *pEnd;             /* First byte past end of available space */
+  void *pTrueEnd;         /* True value of pEnd, when db->pnBytesFreed!=0 */
+};
+struct LookasideSlot {
+  LookasideSlot *pNext;    /* Next buffer in the list of free buffers */
+};
+
+#define DisableLookaside  db->lookaside.bDisable++;db->lookaside.sz=0
+#define EnableLookaside   db->lookaside.bDisable--;\
+   db->lookaside.sz=db->lookaside.bDisable?0:db->lookaside.szTrue
+
+/* Size of the smaller allocations in two-size lookaside */
+#ifdef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+#  define LOOKASIDE_SMALL           0
+#else
+#  define LOOKASIDE_SMALL         128
+#endif
+
+/*
+** A hash table for built-in function definitions.  (Application-defined
+** functions use a regular table table from hash.h.)
+**
+** Hash each FuncDef structure into one of the FuncDefHash.a[] slots.
+** Collisions are on the FuncDef.u.pHash chain.  Use the SQLITE_FUNC_HASH()
+** macro to compute a hash on the function name.
+*/
+#define SQLITE_FUNC_HASH_SZ 23
+struct FuncDefHash {
+  FuncDef *a[SQLITE_FUNC_HASH_SZ];       /* Hash table for functions */
+};
+#define SQLITE_FUNC_HASH(C,L) (((C)+(L))%SQLITE_FUNC_HASH_SZ)
+
+/*
+** typedef for the authorization callback function.
+*/
+typedef int (*sqlite3_xauth)(void*,int,const char*,const char*,const char*,
+                             const char*);
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/* This is an extra SQLITE_TRACE macro that indicates "legacy" tracing
+** in the style of sqlite3_trace()
+*/
+#define SQLITE_TRACE_LEGACY          0x40     /* Use the legacy xTrace */
+#define SQLITE_TRACE_XPROFILE        0x80     /* Use the legacy xProfile */
+#else
+#define SQLITE_TRACE_LEGACY          0
+#define SQLITE_TRACE_XPROFILE        0
+#endif /* SQLITE_OMIT_DEPRECATED */
+#define SQLITE_TRACE_NONLEGACY_MASK  0x0f     /* Normal flags */
+
+/*
+** Maximum number of sqlite3.aDb[] entries.  This is the number of attached
+** databases plus 2 for "main" and "temp".
+*/
+#define SQLITE_MAX_DB (SQLITE_MAX_ATTACHED+2)
+
+/*
+** Each database connection is an instance of the following structure.
+*/
+struct sqlite3 {
+  sqlite3_vfs *pVfs;            /* OS Interface */
+  struct Vdbe *pVdbe;           /* List of active virtual machines */
+  CollSeq *pDfltColl;           /* BINARY collseq for the database encoding */
+  sqlite3_mutex *mutex;         /* Connection mutex */
+  Db *aDb;                      /* All backends */
+  int nDb;                      /* Number of backends currently in use */
+  u32 mDbFlags;                 /* flags recording internal state */
+  u64 flags;                    /* flags settable by pragmas. See below */
+  i64 lastRowid;                /* ROWID of most recent insert (see above) */
+  i64 szMmap;                   /* Default mmap_size setting */
+  u32 nSchemaLock;              /* Do not reset the schema when non-zero */
+  unsigned int openFlags;       /* Flags passed to sqlite3_vfs.xOpen() */
+  int errCode;                  /* Most recent error code (SQLITE_*) */
+  int errByteOffset;            /* Byte offset of error in SQL statement */
+  int errMask;                  /* & result codes with this before returning */
+  int iSysErrno;                /* Errno value from last system error */
+  u32 dbOptFlags;               /* Flags to enable/disable optimizations */
+  u8 enc;                       /* Text encoding */
+  u8 autoCommit;                /* The auto-commit flag. */
+  u8 temp_store;                /* 1: file 2: memory 0: default */
+  u8 mallocFailed;              /* True if we have seen a malloc failure */
+  u8 bBenignMalloc;             /* Do not require OOMs if true */
+  u8 dfltLockMode;              /* Default locking-mode for attached dbs */
+  signed char nextAutovac;      /* Autovac setting after VACUUM if >=0 */
+  u8 suppressErr;               /* Do not issue error messages if true */
+  u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */
+  u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
+  u8 mTrace;                    /* zero or more SQLITE_TRACE flags */
+  u8 noSharedCache;             /* True if no shared-cache backends */
+  u8 nSqlExec;                  /* Number of pending OP_SqlExec opcodes */
+  u8 eOpenState;                /* Current condition of the connection */
+  int nextPagesize;             /* Pagesize after VACUUM if >0 */
+  i64 nChange;                  /* Value returned by sqlite3_changes() */
+  i64 nTotalChange;             /* Value returned by sqlite3_total_changes() */
+  int aLimit[SQLITE_N_LIMIT];   /* Limits */
+  int nMaxSorterMmap;           /* Maximum size of regions mapped by sorter */
+  struct sqlite3InitInfo {      /* Information used during initialization */
+    Pgno newTnum;               /* Rootpage of table being initialized */
+    u8 iDb;                     /* Which db file is being initialized */
+    u8 busy;                    /* TRUE if currently initializing */
+    unsigned orphanTrigger : 1; /* Last statement is orphaned TEMP trigger */
+    unsigned imposterTable : 1; /* Building an imposter table */
+    unsigned reopenMemdb : 1;   /* ATTACH is really a reopen using MemDB */
+    const char **azInit;        /* "type", "name", and "tbl_name" columns */
+  } init;
+  int nVdbeActive;              /* Number of VDBEs currently running */
+  int nVdbeRead;                /* Number of active VDBEs that read or write */
+  int nVdbeWrite;               /* Number of active VDBEs that read and write */
+  int nVdbeExec;                /* Number of nested calls to VdbeExec() */
+  int nVDestroy;                /* Number of active OP_VDestroy operations */
+  int nExtension;               /* Number of loaded extensions */
+  void **aExtension;            /* Array of shared library handles */
+  union {
+    void (*xLegacy)(void*,const char*);   /* mTrace==SQLITE_TRACE_LEGACY */
+    int (*xV2)(u32,void*,void*,void*);    /* All other mTrace values */
+  } trace;
+  void *pTraceArg;                        /* Argument to the trace function */
+#ifndef SQLITE_OMIT_DEPRECATED
+  void (*xProfile)(void*,const char*,u64);  /* Profiling function */
+  void *pProfileArg;                        /* Argument to profile function */
+#endif
+  void *pCommitArg;                 /* Argument to xCommitCallback() */
+  int (*xCommitCallback)(void*);    /* Invoked at every commit. */
+  void *pRollbackArg;               /* Argument to xRollbackCallback() */
+  void (*xRollbackCallback)(void*); /* Invoked at every commit. */
+  void *pUpdateArg;
+  void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);
+  void *pAutovacPagesArg;           /* Client argument to autovac_pages */
+  void (*xAutovacDestr)(void*);     /* Destructor for pAutovacPAgesArg */
+  unsigned int (*xAutovacPages)(void*,const char*,u32,u32,u32);
+  Parse *pParse;                /* Current parse */
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  void *pPreUpdateArg;          /* First argument to xPreUpdateCallback */
+  void (*xPreUpdateCallback)(   /* Registered using sqlite3_preupdate_hook() */
+    void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64
+  );
+  PreUpdate *pPreUpdate;        /* Context for active pre-update callback */
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+#ifndef SQLITE_OMIT_WAL
+  int (*xWalCallback)(void *, sqlite3 *, const char *, int);
+  void *pWalArg;
+#endif
+  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
+  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
+  void *pCollNeededArg;
+  sqlite3_value *pErr;          /* Most recent error message */
+  union {
+    volatile int isInterrupted; /* True if sqlite3_interrupt has been called */
+    double notUsed1;            /* Spacer */
+  } u1;
+  Lookaside lookaside;          /* Lookaside malloc configuration */
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth;          /* Access authorization function */
+  void *pAuthArg;               /* 1st argument to the access auth function */
+#endif
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  int (*xProgress)(void *);     /* The progress callback */
+  void *pProgressArg;           /* Argument to the progress callback */
+  unsigned nProgressOps;        /* Number of opcodes for progress callback */
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  int nVTrans;                  /* Allocated size of aVTrans */
+  Hash aModule;                 /* populated by sqlite3_create_module() */
+  VtabCtx *pVtabCtx;            /* Context for active vtab connect/create */
+  VTable **aVTrans;             /* Virtual tables with open transactions */
+  VTable *pDisconnect;          /* Disconnect these in next sqlite3_prepare() */
+#endif
+  Hash aFunc;                   /* Hash table of connection functions */
+  Hash aCollSeq;                /* All collating sequences */
+  BusyHandler busyHandler;      /* Busy callback */
+  Db aDbStatic[2];              /* Static space for the 2 default backends */
+  Savepoint *pSavepoint;        /* List of active savepoints */
+  int nAnalysisLimit;           /* Number of index rows to ANALYZE */
+  int busyTimeout;              /* Busy handler timeout, in msec */
+  int nSavepoint;               /* Number of non-transaction savepoints */
+  int nStatement;               /* Number of nested statement-transactions  */
+  i64 nDeferredCons;            /* Net deferred constraints this transaction. */
+  i64 nDeferredImmCons;         /* Net deferred immediate constraints */
+  int *pnBytesFreed;            /* If not NULL, increment this in DbFree() */
+  DbClientData *pDbData;        /* sqlite3_set_clientdata() content */
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+  /* The following variables are all protected by the STATIC_MAIN
+  ** mutex, not by sqlite3.mutex. They are used by code in notify.c.
+  **
+  ** When X.pUnlockConnection==Y, that means that X is waiting for Y to
+  ** unlock so that it can proceed.
+  **
+  ** When X.pBlockingConnection==Y, that means that something that X tried
+  ** tried to do recently failed with an SQLITE_LOCKED error due to locks
+  ** held by Y.
+  */
+  sqlite3 *pBlockingConnection; /* Connection that caused SQLITE_LOCKED */
+  sqlite3 *pUnlockConnection;           /* Connection to watch for unlock */
+  void *pUnlockArg;                     /* Argument to xUnlockNotify */
+  void (*xUnlockNotify)(void **, int);  /* Unlock notify callback */
+  sqlite3 *pNextBlocked;        /* Next in list of all blocked connections */
+#endif
+};
+
+/*
+** A macro to discover the encoding of a database.
+*/
+#define SCHEMA_ENC(db) ((db)->aDb[0].pSchema->enc)
+#define ENC(db)        ((db)->enc)
+
+/*
+** A u64 constant where the lower 32 bits are all zeros.  Only the
+** upper 32 bits are included in the argument.  Necessary because some
+** C-compilers still do not accept LL integer literals.
+*/
+#define HI(X)  ((u64)(X)<<32)
+
+/*
+** Possible values for the sqlite3.flags.
+**
+** Value constraints (enforced via assert()):
+**      SQLITE_FullFSync     == PAGER_FULLFSYNC
+**      SQLITE_CkptFullFSync == PAGER_CKPT_FULLFSYNC
+**      SQLITE_CacheSpill    == PAGER_CACHE_SPILL
+*/
+#define SQLITE_WriteSchema    0x00000001  /* OK to update SQLITE_SCHEMA */
+#define SQLITE_LegacyFileFmt  0x00000002  /* Create new databases in format 1 */
+#define SQLITE_FullColNames   0x00000004  /* Show full column names on SELECT */
+#define SQLITE_FullFSync      0x00000008  /* Use full fsync on the backend */
+#define SQLITE_CkptFullFSync  0x00000010  /* Use full fsync for checkpoint */
+#define SQLITE_CacheSpill     0x00000020  /* OK to spill pager cache */
+#define SQLITE_ShortColNames  0x00000040  /* Show short columns names */
+#define SQLITE_TrustedSchema  0x00000080  /* Allow unsafe functions and
+                                          ** vtabs in the schema definition */
+#define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */
+                                          /*   result set is empty */
+#define SQLITE_IgnoreChecks   0x00000200  /* Do not enforce check constraints */
+#define SQLITE_StmtScanStatus 0x00000400  /* Enable stmt_scanstats() counters */
+#define SQLITE_NoCkptOnClose  0x00000800  /* No checkpoint on close()/DETACH */
+#define SQLITE_ReverseOrder   0x00001000  /* Reverse unordered SELECTs */
+#define SQLITE_RecTriggers    0x00002000  /* Enable recursive triggers */
+#define SQLITE_ForeignKeys    0x00004000  /* Enforce foreign key constraints  */
+#define SQLITE_AutoIndex      0x00008000  /* Enable automatic indexes */
+#define SQLITE_LoadExtension  0x00010000  /* Enable load_extension */
+#define SQLITE_LoadExtFunc    0x00020000  /* Enable load_extension() SQL func */
+#define SQLITE_EnableTrigger  0x00040000  /* True to enable triggers */
+#define SQLITE_DeferFKs       0x00080000  /* Defer all FK constraints */
+#define SQLITE_QueryOnly      0x00100000  /* Disable database changes */
+#define SQLITE_CellSizeCk     0x00200000  /* Check btree cell sizes on load */
+#define SQLITE_Fts3Tokenizer  0x00400000  /* Enable fts3_tokenizer(2) */
+#define SQLITE_EnableQPSG     0x00800000  /* Query Planner Stability Guarantee*/
+#define SQLITE_TriggerEQP     0x01000000  /* Show trigger EXPLAIN QUERY PLAN */
+#define SQLITE_ResetDatabase  0x02000000  /* Reset the database */
+#define SQLITE_LegacyAlter    0x04000000  /* Legacy ALTER TABLE behaviour */
+#define SQLITE_NoSchemaError  0x08000000  /* Do not report schema parse errors*/
+#define SQLITE_Defensive      0x10000000  /* Input SQL is likely hostile */
+#define SQLITE_DqsDDL         0x20000000  /* dbl-quoted strings allowed in DDL*/
+#define SQLITE_DqsDML         0x40000000  /* dbl-quoted strings allowed in DML*/
+#define SQLITE_EnableView     0x80000000  /* Enable the use of views */
+#define SQLITE_CountRows      HI(0x00001) /* Count rows changed by INSERT, */
+                                          /*   DELETE, or UPDATE and return */
+                                          /*   the count using a callback. */
+#define SQLITE_CorruptRdOnly  HI(0x00002) /* Prohibit writes due to error */
+#define SQLITE_ReadUncommit   HI(0x00004) /* READ UNCOMMITTED in shared-cache */
+#define SQLITE_FkNoAction     HI(0x00008) /* Treat all FK as NO ACTION */
+#define SQLITE_AttachCreate   HI(0x00010) /* ATTACH allowed to create new dbs */
+#define SQLITE_AttachWrite    HI(0x00020) /* ATTACH allowed to open for write */
+#define SQLITE_Comments       HI(0x00040) /* Enable SQL comments */
+
+/* Flags used only if debugging */
+#ifdef SQLITE_DEBUG
+#define SQLITE_SqlTrace       HI(0x0100000) /* Debug print SQL as it executes */
+#define SQLITE_VdbeListing    HI(0x0200000) /* Debug listings of VDBE progs */
+#define SQLITE_VdbeTrace      HI(0x0400000) /* True to trace VDBE execution */
+#define SQLITE_VdbeAddopTrace HI(0x0800000) /* Trace sqlite3VdbeAddOp() calls */
+#define SQLITE_VdbeEQP        HI(0x1000000) /* Debug EXPLAIN QUERY PLAN */
+#define SQLITE_ParserTrace    HI(0x2000000) /* PRAGMA parser_trace=ON */
+#endif
+
+/*
+** Allowed values for sqlite3.mDbFlags
+*/
+#define DBFLAG_SchemaChange   0x0001  /* Uncommitted Hash table changes */
+#define DBFLAG_PreferBuiltin  0x0002  /* Preference to built-in funcs */
+#define DBFLAG_Vacuum         0x0004  /* Currently in a VACUUM */
+#define DBFLAG_VacuumInto     0x0008  /* Currently running VACUUM INTO */
+#define DBFLAG_SchemaKnownOk  0x0010  /* Schema is known to be valid */
+#define DBFLAG_InternalFunc   0x0020  /* Allow use of internal functions */
+#define DBFLAG_EncodingFixed  0x0040  /* No longer possible to change enc. */
+
+/*
+** Bits of the sqlite3.dbOptFlags field that are used by the
+** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface to
+** selectively disable various optimizations.
+*/
+#define SQLITE_QueryFlattener 0x00000001 /* Query flattening */
+#define SQLITE_WindowFunc     0x00000002 /* Use xInverse for window functions */
+#define SQLITE_GroupByOrder   0x00000004 /* GROUPBY cover of ORDERBY */
+#define SQLITE_FactorOutConst 0x00000008 /* Constant factoring */
+#define SQLITE_DistinctOpt    0x00000010 /* DISTINCT using indexes */
+#define SQLITE_CoverIdxScan   0x00000020 /* Covering index scans */
+#define SQLITE_OrderByIdxJoin 0x00000040 /* ORDER BY of joins via index */
+#define SQLITE_Transitive     0x00000080 /* Transitive constraints */
+#define SQLITE_OmitNoopJoin   0x00000100 /* Omit unused tables in joins */
+#define SQLITE_CountOfView    0x00000200 /* The count-of-view optimization */
+#define SQLITE_CursorHints    0x00000400 /* Add OP_CursorHint opcodes */
+#define SQLITE_Stat4          0x00000800 /* Use STAT4 data */
+   /* TH3 expects this value  ^^^^^^^^^^ to be 0x0000800. Don't change it */
+#define SQLITE_PushDown       0x00001000 /* WHERE-clause push-down opt */
+#define SQLITE_SimplifyJoin   0x00002000 /* Convert LEFT JOIN to JOIN */
+#define SQLITE_SkipScan       0x00004000 /* Skip-scans */
+#define SQLITE_PropagateConst 0x00008000 /* The constant propagation opt */
+#define SQLITE_MinMaxOpt      0x00010000 /* The min/max optimization */
+#define SQLITE_SeekScan       0x00020000 /* The OP_SeekScan optimization */
+#define SQLITE_OmitOrderBy    0x00040000 /* Omit pointless ORDER BY */
+   /* TH3 expects this value  ^^^^^^^^^^ to be 0x40000. Coordinate any change */
+#define SQLITE_BloomFilter    0x00080000 /* Use a Bloom filter on searches */
+#define SQLITE_BloomPulldown  0x00100000 /* Run Bloom filters early */
+#define SQLITE_BalancedMerge  0x00200000 /* Balance multi-way merges */
+#define SQLITE_ReleaseReg     0x00400000 /* Use OP_ReleaseReg for testing */
+#define SQLITE_FlttnUnionAll  0x00800000 /* Disable the UNION ALL flattener */
+   /* TH3 expects this value  ^^^^^^^^^^ See flatten04.test */
+#define SQLITE_IndexedExpr    0x01000000 /* Pull exprs from index when able */
+#define SQLITE_Coroutines     0x02000000 /* Co-routines for subqueries */
+#define SQLITE_NullUnusedCols 0x04000000 /* NULL unused columns in subqueries */
+#define SQLITE_OnePass        0x08000000 /* Single-pass DELETE and UPDATE */
+#define SQLITE_OrderBySubq    0x10000000 /* ORDER BY in subquery helps outer */
+#define SQLITE_StarQuery      0x20000000 /* Heurists for star queries */
+#define SQLITE_AllOpts        0xffffffff /* All optimizations */
+
+/*
+** Macros for testing whether or not optimizations are enabled or disabled.
+*/
+#define OptimizationDisabled(db, mask)  (((db)->dbOptFlags&(mask))!=0)
+#define OptimizationEnabled(db, mask)   (((db)->dbOptFlags&(mask))==0)
+
+/*
+** Return true if it OK to factor constant expressions into the initialization
+** code. The argument is a Parse object for the code generator.
+*/
+#define ConstFactorOk(P) ((P)->okConstFactor)
+
+/* Possible values for the sqlite3.eOpenState field.
+** The numbers are randomly selected such that a minimum of three bits must
+** change to convert any number to another or to zero
+*/
+#define SQLITE_STATE_OPEN     0x76  /* Database is open */
+#define SQLITE_STATE_CLOSED   0xce  /* Database is closed */
+#define SQLITE_STATE_SICK     0xba  /* Error and awaiting close */
+#define SQLITE_STATE_BUSY     0x6d  /* Database currently in use */
+#define SQLITE_STATE_ERROR    0xd5  /* An SQLITE_MISUSE error occurred */
+#define SQLITE_STATE_ZOMBIE   0xa7  /* Close with last statement close */
+
+/*
+** Each SQL function is defined by an instance of the following
+** structure.  For global built-in functions (ex: substr(), max(), count())
+** a pointer to this structure is held in the sqlite3BuiltinFunctions object.
+** For per-connection application-defined functions, a pointer to this
+** structure is held in the db->aHash hash table.
+**
+** The u.pHash field is used by the global built-ins.  The u.pDestructor
+** field is used by per-connection app-def functions.
+*/
+struct FuncDef {
+  i16 nArg;            /* Number of arguments.  -1 means unlimited */
+  u32 funcFlags;       /* Some combination of SQLITE_FUNC_* */
+  void *pUserData;     /* User data parameter */
+  FuncDef *pNext;      /* Next function with same name */
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value**); /* func or agg-step */
+  void (*xFinalize)(sqlite3_context*);                  /* Agg finalizer */
+  void (*xValue)(sqlite3_context*);                     /* Current agg value */
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value**); /* inverse agg-step */
+  const char *zName;   /* SQL name of the function. */
+  union {
+    FuncDef *pHash;      /* Next with a different name but the same hash */
+    FuncDestructor *pDestructor;   /* Reference counted destructor function */
+  } u; /* pHash if SQLITE_FUNC_BUILTIN, pDestructor otherwise */
+};
+
+/*
+** This structure encapsulates a user-function destructor callback (as
+** configured using create_function_v2()) and a reference counter. When
+** create_function_v2() is called to create a function with a destructor,
+** a single object of this type is allocated. FuncDestructor.nRef is set to
+** the number of FuncDef objects created (either 1 or 3, depending on whether
+** or not the specified encoding is SQLITE_ANY). The FuncDef.pDestructor
+** member of each of the new FuncDef objects is set to point to the allocated
+** FuncDestructor.
+**
+** Thereafter, when one of the FuncDef objects is deleted, the reference
+** count on this object is decremented. When it reaches 0, the destructor
+** is invoked and the FuncDestructor structure freed.
+*/
+struct FuncDestructor {
+  int nRef;
+  void (*xDestroy)(void *);
+  void *pUserData;
+};
+
+/*
+** Possible values for FuncDef.flags.  Note that the _LENGTH and _TYPEOF
+** values must correspond to OPFLAG_LENGTHARG and OPFLAG_TYPEOFARG.  And
+** SQLITE_FUNC_CONSTANT must be the same as SQLITE_DETERMINISTIC.  There
+** are assert() statements in the code to verify this.
+**
+** Value constraints (enforced via assert()):
+**     SQLITE_FUNC_MINMAX      ==  NC_MinMaxAgg      == SF_MinMaxAgg
+**     SQLITE_FUNC_ANYORDER    ==  NC_OrderAgg       == SF_OrderByReqd
+**     SQLITE_FUNC_LENGTH      ==  OPFLAG_LENGTHARG
+**     SQLITE_FUNC_TYPEOF      ==  OPFLAG_TYPEOFARG
+**     SQLITE_FUNC_BYTELEN     ==  OPFLAG_BYTELENARG
+**     SQLITE_FUNC_CONSTANT    ==  SQLITE_DETERMINISTIC from the API
+**     SQLITE_FUNC_DIRECT      ==  SQLITE_DIRECTONLY from the API
+**     SQLITE_FUNC_UNSAFE      ==  SQLITE_INNOCUOUS  -- opposite meanings!!!
+**     SQLITE_FUNC_ENCMASK   depends on SQLITE_UTF* macros in the API
+**
+** Note that even though SQLITE_FUNC_UNSAFE and SQLITE_INNOCUOUS have the
+** same bit value, their meanings are inverted.  SQLITE_FUNC_UNSAFE is
+** used internally and if set means that the function has side effects.
+** SQLITE_INNOCUOUS is used by application code and means "not unsafe".
+** See multiple instances of tag-20230109-1.
+*/
+#define SQLITE_FUNC_ENCMASK  0x0003 /* SQLITE_UTF8, SQLITE_UTF16BE or UTF16LE */
+#define SQLITE_FUNC_LIKE     0x0004 /* Candidate for the LIKE optimization */
+#define SQLITE_FUNC_CASE     0x0008 /* Case-sensitive LIKE-type function */
+#define SQLITE_FUNC_EPHEM    0x0010 /* Ephemeral.  Delete with VDBE */
+#define SQLITE_FUNC_NEEDCOLL 0x0020 /* sqlite3GetFuncCollSeq() might be called*/
+#define SQLITE_FUNC_LENGTH   0x0040 /* Built-in length() function */
+#define SQLITE_FUNC_TYPEOF   0x0080 /* Built-in typeof() function */
+#define SQLITE_FUNC_BYTELEN  0x00c0 /* Built-in octet_length() function */
+#define SQLITE_FUNC_COUNT    0x0100 /* Built-in count(*) aggregate */
+/*                           0x0200 -- available for reuse */
+#define SQLITE_FUNC_UNLIKELY 0x0400 /* Built-in unlikely() function */
+#define SQLITE_FUNC_CONSTANT 0x0800 /* Constant inputs give a constant output */
+#define SQLITE_FUNC_MINMAX   0x1000 /* True for min() and max() aggregates */
+#define SQLITE_FUNC_SLOCHNG  0x2000 /* "Slow Change". Value constant during a
+                                    ** single query - might change over time */
+#define SQLITE_FUNC_TEST     0x4000 /* Built-in testing functions */
+#define SQLITE_FUNC_RUNONLY  0x8000 /* Cannot be used by valueFromFunction */
+#define SQLITE_FUNC_WINDOW   0x00010000 /* Built-in window-only function */
+#define SQLITE_FUNC_INTERNAL 0x00040000 /* For use by NestedParse() only */
+#define SQLITE_FUNC_DIRECT   0x00080000 /* Not for use in TRIGGERs or VIEWs */
+/* SQLITE_SUBTYPE            0x00100000 // Consumer of subtypes */
+#define SQLITE_FUNC_UNSAFE   0x00200000 /* Function has side effects */
+#define SQLITE_FUNC_INLINE   0x00400000 /* Functions implemented in-line */
+#define SQLITE_FUNC_BUILTIN  0x00800000 /* This is a built-in function */
+/*  SQLITE_RESULT_SUBTYPE    0x01000000 // Generator of subtypes */
+#define SQLITE_FUNC_ANYORDER 0x08000000 /* count/min/max aggregate */
+
+/* Identifier numbers for each in-line function */
+#define INLINEFUNC_coalesce             0
+#define INLINEFUNC_implies_nonnull_row  1
+#define INLINEFUNC_expr_implies_expr    2
+#define INLINEFUNC_expr_compare         3
+#define INLINEFUNC_affinity             4
+#define INLINEFUNC_iif                  5
+#define INLINEFUNC_sqlite_offset        6
+#define INLINEFUNC_unlikely            99  /* Default case */
+
+/*
+** The following three macros, FUNCTION(), LIKEFUNC() and AGGREGATE() are
+** used to create the initializers for the FuncDef structures.
+**
+**   FUNCTION(zName, nArg, iArg, bNC, xFunc)
+**     Used to create a scalar function definition of a function zName
+**     implemented by C function xFunc that accepts nArg arguments. The
+**     value passed as iArg is cast to a (void*) and made available
+**     as the user-data (sqlite3_user_data()) for the function. If
+**     argument bNC is true, then the SQLITE_FUNC_NEEDCOLL flag is set.
+**
+**   VFUNCTION(zName, nArg, iArg, bNC, xFunc)
+**     Like FUNCTION except it omits the SQLITE_FUNC_CONSTANT flag.
+**
+**   SFUNCTION(zName, nArg, iArg, bNC, xFunc)
+**     Like FUNCTION except it omits the SQLITE_FUNC_CONSTANT flag and
+**     adds the SQLITE_DIRECTONLY flag.
+**
+**   INLINE_FUNC(zName, nArg, iFuncId, mFlags)
+**     zName is the name of a function that is implemented by in-line
+**     byte code rather than by the usual callbacks. The iFuncId
+**     parameter determines the function id.  The mFlags parameter is
+**     optional SQLITE_FUNC_ flags for this function.
+**
+**   TEST_FUNC(zName, nArg, iFuncId, mFlags)
+**     zName is the name of a test-only function implemented by in-line
+**     byte code rather than by the usual callbacks. The iFuncId
+**     parameter determines the function id.  The mFlags parameter is
+**     optional SQLITE_FUNC_ flags for this function.
+**
+**   DFUNCTION(zName, nArg, iArg, bNC, xFunc)
+**     Like FUNCTION except it omits the SQLITE_FUNC_CONSTANT flag and
+**     adds the SQLITE_FUNC_SLOCHNG flag.  Used for date & time functions
+**     and functions like sqlite_version() that can change, but not during
+**     a single query.  The iArg is ignored.  The user-data is always set
+**     to a NULL pointer.  The bNC parameter is not used.
+**
+**   MFUNCTION(zName, nArg, xPtr, xFunc)
+**     For math-library functions.  xPtr is an arbitrary pointer.
+**
+**   PURE_DATE(zName, nArg, iArg, bNC, xFunc)
+**     Used for "pure" date/time functions, this macro is like DFUNCTION
+**     except that it does set the SQLITE_FUNC_CONSTANT flags.  iArg is
+**     ignored and the user-data for these functions is set to an
+**     arbitrary non-NULL pointer.  The bNC parameter is not used.
+**
+**   AGGREGATE(zName, nArg, iArg, bNC, xStep, xFinal)
+**     Used to create an aggregate function definition implemented by
+**     the C functions xStep and xFinal. The first four parameters
+**     are interpreted in the same way as the first 4 parameters to
+**     FUNCTION().
+**
+**   WAGGREGATE(zName, nArg, iArg, xStep, xFinal, xValue, xInverse)
+**     Used to create an aggregate function definition implemented by
+**     the C functions xStep and xFinal. The first four parameters
+**     are interpreted in the same way as the first 4 parameters to
+**     FUNCTION().
+**
+**   LIKEFUNC(zName, nArg, pArg, flags)
+**     Used to create a scalar function definition of a function zName
+**     that accepts nArg arguments and is implemented by a call to C
+**     function likeFunc. Argument pArg is cast to a (void *) and made
+**     available as the function user-data (sqlite3_user_data()). The
+**     FuncDef.flags variable is set to the value passed as the flags
+**     parameter.
+*/
+#define FUNCTION(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_FUNC_CONSTANT|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, 0, #zName, {0} }
+#define VFUNCTION(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, 0, #zName, {0} }
+#define SFUNCTION(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_DIRECTONLY|SQLITE_FUNC_UNSAFE, \
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, 0, #zName, {0} }
+#define MFUNCTION(zName, nArg, xPtr, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_FUNC_CONSTANT|SQLITE_UTF8, \
+   xPtr, 0, xFunc, 0, 0, 0, #zName, {0} }
+#define JFUNCTION(zName, nArg, bUseCache, bWS, bRS, bJsonB, iArg, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_DETERMINISTIC|SQLITE_FUNC_CONSTANT|\
+   SQLITE_UTF8|((bUseCache)*SQLITE_FUNC_RUNONLY)|\
+   ((bRS)*SQLITE_SUBTYPE)|((bWS)*SQLITE_RESULT_SUBTYPE), \
+   SQLITE_INT_TO_PTR(iArg|((bJsonB)*JSON_BLOB)),0,xFunc,0, 0, 0, #zName, {0} }
+#define INLINE_FUNC(zName, nArg, iArg, mFlags) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_UTF8|SQLITE_FUNC_INLINE|SQLITE_FUNC_CONSTANT|(mFlags), \
+   SQLITE_INT_TO_PTR(iArg), 0, noopFunc, 0, 0, 0, #zName, {0} }
+#define TEST_FUNC(zName, nArg, iArg, mFlags) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+         SQLITE_UTF8|SQLITE_FUNC_INTERNAL|SQLITE_FUNC_TEST| \
+         SQLITE_FUNC_INLINE|SQLITE_FUNC_CONSTANT|(mFlags), \
+   SQLITE_INT_TO_PTR(iArg), 0, noopFunc, 0, 0, 0, #zName, {0} }
+#define DFUNCTION(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_FUNC_SLOCHNG|SQLITE_UTF8, \
+   0, 0, xFunc, 0, 0, 0, #zName, {0} }
+#define PURE_DATE(zName, nArg, iArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+         SQLITE_FUNC_SLOCHNG|SQLITE_UTF8|SQLITE_FUNC_CONSTANT, \
+   (void*)&sqlite3Config, 0, xFunc, 0, 0, 0, #zName, {0} }
+#define FUNCTION2(zName, nArg, iArg, bNC, xFunc, extraFlags) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_FUNC_CONSTANT|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL)|extraFlags,\
+   SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, 0, #zName, {0} }
+#define STR_FUNCTION(zName, nArg, pArg, bNC, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_FUNC_SLOCHNG|SQLITE_UTF8|(bNC*SQLITE_FUNC_NEEDCOLL), \
+   pArg, 0, xFunc, 0, 0, 0, #zName, }
+#define LIKEFUNC(zName, nArg, arg, flags) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_FUNC_CONSTANT|SQLITE_UTF8|flags, \
+   (void *)arg, 0, likeFunc, 0, 0, 0, #zName, {0} }
+#define WAGGREGATE(zName, nArg, arg, nc, xStep, xFinal, xValue, xInverse, f) \
+  {nArg, SQLITE_FUNC_BUILTIN|SQLITE_UTF8|(nc*SQLITE_FUNC_NEEDCOLL)|f, \
+   SQLITE_INT_TO_PTR(arg), 0, xStep,xFinal,xValue,xInverse,#zName, {0}}
+#define INTERNAL_FUNCTION(zName, nArg, xFunc) \
+  {nArg, SQLITE_FUNC_BUILTIN|\
+   SQLITE_FUNC_INTERNAL|SQLITE_UTF8|SQLITE_FUNC_CONSTANT, \
+   0, 0, xFunc, 0, 0, 0, #zName, {0} }
+
+
+/*
+** All current savepoints are stored in a linked list starting at
+** sqlite3.pSavepoint. The first element in the list is the most recently
+** opened savepoint. Savepoints are added to the list by the vdbe
+** OP_Savepoint instruction.
+*/
+struct Savepoint {
+  char *zName;                        /* Savepoint name (nul-terminated) */
+  i64 nDeferredCons;                  /* Number of deferred fk violations */
+  i64 nDeferredImmCons;               /* Number of deferred imm fk. */
+  Savepoint *pNext;                   /* Parent savepoint (if any) */
+};
+
+/*
+** The following are used as the second parameter to sqlite3Savepoint(),
+** and as the P1 argument to the OP_Savepoint instruction.
+*/
+#define SAVEPOINT_BEGIN      0
+#define SAVEPOINT_RELEASE    1
+#define SAVEPOINT_ROLLBACK   2
+
+
+/*
+** Each SQLite module (virtual table definition) is defined by an
+** instance of the following structure, stored in the sqlite3.aModule
+** hash table.
+*/
+struct Module {
+  const sqlite3_module *pModule;       /* Callback pointers */
+  const char *zName;                   /* Name passed to create_module() */
+  int nRefModule;                      /* Number of pointers to this object */
+  void *pAux;                          /* pAux passed to create_module() */
+  void (*xDestroy)(void *);            /* Module destructor function */
+  Table *pEpoTab;                      /* Eponymous table for this module */
+};
+
+/*
+** Information about each column of an SQL table is held in an instance
+** of the Column structure, in the Table.aCol[] array.
+**
+** Definitions:
+**
+**   "table column index"     This is the index of the column in the
+**                            Table.aCol[] array, and also the index of
+**                            the column in the original CREATE TABLE stmt.
+**
+**   "storage column index"   This is the index of the column in the
+**                            record BLOB generated by the OP_MakeRecord
+**                            opcode.  The storage column index is less than
+**                            or equal to the table column index.  It is
+**                            equal if and only if there are no VIRTUAL
+**                            columns to the left.
+**
+** Notes on zCnName:
+** The zCnName field stores the name of the column, the datatype of the
+** column, and the collating sequence for the column, in that order, all in
+** a single allocation.  Each string is 0x00 terminated.  The datatype
+** is only included if the COLFLAG_HASTYPE bit of colFlags is set and the
+** collating sequence name is only included if the COLFLAG_HASCOLL bit is
+** set.
+*/
+struct Column {
+  char *zCnName;        /* Name of this column */
+  unsigned notNull :4;  /* An OE_ code for handling a NOT NULL constraint */
+  unsigned eCType :4;   /* One of the standard types */
+  char affinity;        /* One of the SQLITE_AFF_... values */
+  u8 szEst;             /* Est size of value in this column. sizeof(INT)==1 */
+  u8 hName;             /* Column name hash for faster lookup */
+  u16 iDflt;            /* 1-based index of DEFAULT.  0 means "none" */
+  u16 colFlags;         /* Boolean properties.  See COLFLAG_ defines below */
+};
+
+/* Allowed values for Column.eCType.
+**
+** Values must match entries in the global constant arrays
+** sqlite3StdTypeLen[] and sqlite3StdType[].  Each value is one more
+** than the offset into these arrays for the corresponding name.
+** Adjust the SQLITE_N_STDTYPE value if adding or removing entries.
+*/
+#define COLTYPE_CUSTOM      0   /* Type appended to zName */
+#define COLTYPE_ANY         1
+#define COLTYPE_BLOB        2
+#define COLTYPE_INT         3
+#define COLTYPE_INTEGER     4
+#define COLTYPE_REAL        5
+#define COLTYPE_TEXT        6
+#define SQLITE_N_STDTYPE    6  /* Number of standard types */
+
+/* Allowed values for Column.colFlags.
+**
+** Constraints:
+**         TF_HasVirtual == COLFLAG_VIRTUAL
+**         TF_HasStored  == COLFLAG_STORED
+**         TF_HasHidden  == COLFLAG_HIDDEN
+*/
+#define COLFLAG_PRIMKEY   0x0001   /* Column is part of the primary key */
+#define COLFLAG_HIDDEN    0x0002   /* A hidden column in a virtual table */
+#define COLFLAG_HASTYPE   0x0004   /* Type name follows column name */
+#define COLFLAG_UNIQUE    0x0008   /* Column def contains "UNIQUE" or "PK" */
+#define COLFLAG_SORTERREF 0x0010   /* Use sorter-refs with this column */
+#define COLFLAG_VIRTUAL   0x0020   /* GENERATED ALWAYS AS ... VIRTUAL */
+#define COLFLAG_STORED    0x0040   /* GENERATED ALWAYS AS ... STORED */
+#define COLFLAG_NOTAVAIL  0x0080   /* STORED column not yet calculated */
+#define COLFLAG_BUSY      0x0100   /* Blocks recursion on GENERATED columns */
+#define COLFLAG_HASCOLL   0x0200   /* Has collating sequence name in zCnName */
+#define COLFLAG_NOEXPAND  0x0400   /* Omit this column when expanding "*" */
+#define COLFLAG_GENERATED 0x0060   /* Combo: _STORED, _VIRTUAL */
+#define COLFLAG_NOINSERT  0x0062   /* Combo: _HIDDEN, _STORED, _VIRTUAL */
+
+/*
+** A "Collating Sequence" is defined by an instance of the following
+** structure. Conceptually, a collating sequence consists of a name and
+** a comparison routine that defines the order of that sequence.
+**
+** If CollSeq.xCmp is NULL, it means that the
+** collating sequence is undefined.  Indices built on an undefined
+** collating sequence may not be read or written.
+*/
+struct CollSeq {
+  char *zName;          /* Name of the collating sequence, UTF-8 encoded */
+  u8 enc;               /* Text encoding handled by xCmp() */
+  void *pUser;          /* First argument to xCmp() */
+  int (*xCmp)(void*,int, const void*, int, const void*);
+  void (*xDel)(void*);  /* Destructor for pUser */
+};
+
+/*
+** A sort order can be either ASC or DESC.
+*/
+#define SQLITE_SO_ASC       0  /* Sort in ascending order */
+#define SQLITE_SO_DESC      1  /* Sort in ascending order */
+#define SQLITE_SO_UNDEFINED -1 /* No sort order specified */
+
+/*
+** Column affinity types.
+**
+** These used to have mnemonic name like 'i' for SQLITE_AFF_INTEGER and
+** 't' for SQLITE_AFF_TEXT.  But we can save a little space and improve
+** the speed a little by numbering the values consecutively.
+**
+** But rather than start with 0 or 1, we begin with 'A'.  That way,
+** when multiple affinity types are concatenated into a string and
+** used as the P4 operand, they will be more readable.
+**
+** Note also that the numeric types are grouped together so that testing
+** for a numeric type is a single comparison.  And the BLOB type is first.
+*/
+#define SQLITE_AFF_NONE     0x40  /* '@' */
+#define SQLITE_AFF_BLOB     0x41  /* 'A' */
+#define SQLITE_AFF_TEXT     0x42  /* 'B' */
+#define SQLITE_AFF_NUMERIC  0x43  /* 'C' */
+#define SQLITE_AFF_INTEGER  0x44  /* 'D' */
+#define SQLITE_AFF_REAL     0x45  /* 'E' */
+#define SQLITE_AFF_FLEXNUM  0x46  /* 'F' */
+
+#define sqlite3IsNumericAffinity(X)  ((X)>=SQLITE_AFF_NUMERIC)
+
+/*
+** The SQLITE_AFF_MASK values masks off the significant bits of an
+** affinity value.
+*/
+#define SQLITE_AFF_MASK     0x47
+
+/*
+** Additional bit values that can be ORed with an affinity without
+** changing the affinity.
+**
+** The SQLITE_NOTNULL flag is a combination of NULLEQ and JUMPIFNULL.
+** It causes an assert() to fire if either operand to a comparison
+** operator is NULL.  It is added to certain comparison operators to
+** prove that the operands are always NOT NULL.
+*/
+#define SQLITE_JUMPIFNULL   0x10  /* jumps if either operand is NULL */
+#define SQLITE_NULLEQ       0x80  /* NULL=NULL */
+#define SQLITE_NOTNULL      0x90  /* Assert that operands are never NULL */
+
+/*
+** An object of this type is created for each virtual table present in
+** the database schema.
+**
+** If the database schema is shared, then there is one instance of this
+** structure for each database connection (sqlite3*) that uses the shared
+** schema. This is because each database connection requires its own unique
+** instance of the sqlite3_vtab* handle used to access the virtual table
+** implementation. sqlite3_vtab* handles can not be shared between
+** database connections, even when the rest of the in-memory database
+** schema is shared, as the implementation often stores the database
+** connection handle passed to it via the xConnect() or xCreate() method
+** during initialization internally. This database connection handle may
+** then be used by the virtual table implementation to access real tables
+** within the database. So that they appear as part of the callers
+** transaction, these accesses need to be made via the same database
+** connection as that used to execute SQL operations on the virtual table.
+**
+** All VTable objects that correspond to a single table in a shared
+** database schema are initially stored in a linked-list pointed to by
+** the Table.pVTable member variable of the corresponding Table object.
+** When an sqlite3_prepare() operation is required to access the virtual
+** table, it searches the list for the VTable that corresponds to the
+** database connection doing the preparing so as to use the correct
+** sqlite3_vtab* handle in the compiled query.
+**
+** When an in-memory Table object is deleted (for example when the
+** schema is being reloaded for some reason), the VTable objects are not
+** deleted and the sqlite3_vtab* handles are not xDisconnect()ed
+** immediately. Instead, they are moved from the Table.pVTable list to
+** another linked list headed by the sqlite3.pDisconnect member of the
+** corresponding sqlite3 structure. They are then deleted/xDisconnected
+** next time a statement is prepared using said sqlite3*. This is done
+** to avoid deadlock issues involving multiple sqlite3.mutex mutexes.
+** Refer to comments above function sqlite3VtabUnlockList() for an
+** explanation as to why it is safe to add an entry to an sqlite3.pDisconnect
+** list without holding the corresponding sqlite3.mutex mutex.
+**
+** The memory for objects of this type is always allocated by
+** sqlite3DbMalloc(), using the connection handle stored in VTable.db as
+** the first argument.
+*/
+struct VTable {
+  sqlite3 *db;              /* Database connection associated with this table */
+  Module *pMod;             /* Pointer to module implementation */
+  sqlite3_vtab *pVtab;      /* Pointer to vtab instance */
+  int nRef;                 /* Number of pointers to this structure */
+  u8 bConstraint;           /* True if constraints are supported */
+  u8 bAllSchemas;           /* True if might use any attached schema */
+  u8 eVtabRisk;             /* Riskiness of allowing hacker access */
+  int iSavepoint;           /* Depth of the SAVEPOINT stack */
+  VTable *pNext;            /* Next in linked list (see above) */
+};
+
+/* Allowed values for VTable.eVtabRisk
+*/
+#define SQLITE_VTABRISK_Low          0
+#define SQLITE_VTABRISK_Normal       1
+#define SQLITE_VTABRISK_High         2
+
+/*
+** The schema for each SQL table, virtual table, and view is represented
+** in memory by an instance of the following structure.
+*/
+struct Table {
+  char *zName;         /* Name of the table or view */
+  Column *aCol;        /* Information about each column */
+  Index *pIndex;       /* List of SQL indexes on this table. */
+  char *zColAff;       /* String defining the affinity of each column */
+  ExprList *pCheck;    /* All CHECK constraints */
+                       /*   ... also used as column name list in a VIEW */
+  Pgno tnum;           /* Root BTree page for this table */
+  u32 nTabRef;         /* Number of pointers to this Table */
+  u32 tabFlags;        /* Mask of TF_* values */
+  i16 iPKey;           /* If not negative, use aCol[iPKey] as the rowid */
+  i16 nCol;            /* Number of columns in this table */
+  i16 nNVCol;          /* Number of columns that are not VIRTUAL */
+  LogEst nRowLogEst;   /* Estimated rows in table - from sqlite_stat1 table */
+  LogEst szTabRow;     /* Estimated size of each table row in bytes */
+#ifdef SQLITE_ENABLE_COSTMULT
+  LogEst costMult;     /* Cost multiplier for using this table */
+#endif
+  u8 keyConf;          /* What to do in case of uniqueness conflict on iPKey */
+  u8 eTabType;         /* 0: normal, 1: virtual, 2: view */
+  union {
+    struct {             /* Used by ordinary tables: */
+      int addColOffset;    /* Offset in CREATE TABLE stmt to add a new column */
+      FKey *pFKey;         /* Linked list of all foreign keys in this table */
+      ExprList *pDfltList; /* DEFAULT clauses on various columns.
+                           ** Or the AS clause for generated columns. */
+    } tab;
+    struct {             /* Used by views: */
+      Select *pSelect;     /* View definition */
+    } view;
+    struct {             /* Used by virtual tables only: */
+      int nArg;            /* Number of arguments to the module */
+      char **azArg;        /* 0: module 1: schema 2: vtab name 3...: args */
+      VTable *p;           /* List of VTable objects. */
+    } vtab;
+  } u;
+  Trigger *pTrigger;   /* List of triggers on this object */
+  Schema *pSchema;     /* Schema that contains this table */
+};
+
+/*
+** Allowed values for Table.tabFlags.
+**
+** TF_OOOHidden applies to tables or view that have hidden columns that are
+** followed by non-hidden columns.  Example:  "CREATE VIRTUAL TABLE x USING
+** vtab1(a HIDDEN, b);".  Since "b" is a non-hidden column but "a" is hidden,
+** the TF_OOOHidden attribute would apply in this case.  Such tables require
+** special handling during INSERT processing. The "OOO" means "Out Of Order".
+**
+** Constraints:
+**
+**         TF_HasVirtual == COLFLAG_VIRTUAL
+**         TF_HasStored  == COLFLAG_STORED
+**         TF_HasHidden  == COLFLAG_HIDDEN
+*/
+#define TF_Readonly       0x00000001 /* Read-only system table */
+#define TF_HasHidden      0x00000002 /* Has one or more hidden columns */
+#define TF_HasPrimaryKey  0x00000004 /* Table has a primary key */
+#define TF_Autoincrement  0x00000008 /* Integer primary key is autoincrement */
+#define TF_HasStat1       0x00000010 /* nRowLogEst set from sqlite_stat1 */
+#define TF_HasVirtual     0x00000020 /* Has one or more VIRTUAL columns */
+#define TF_HasStored      0x00000040 /* Has one or more STORED columns */
+#define TF_HasGenerated   0x00000060 /* Combo: HasVirtual + HasStored */
+#define TF_WithoutRowid   0x00000080 /* No rowid.  PRIMARY KEY is the key */
+#define TF_MaybeReanalyze 0x00000100 /* Maybe run ANALYZE on this table */
+#define TF_NoVisibleRowid 0x00000200 /* No user-visible "rowid" column */
+#define TF_OOOHidden      0x00000400 /* Out-of-Order hidden columns */
+#define TF_HasNotNull     0x00000800 /* Contains NOT NULL constraints */
+#define TF_Shadow         0x00001000 /* True for a shadow table */
+#define TF_HasStat4       0x00002000 /* STAT4 info available for this table */
+#define TF_Ephemeral      0x00004000 /* An ephemeral table */
+#define TF_Eponymous      0x00008000 /* An eponymous virtual table */
+#define TF_Strict         0x00010000 /* STRICT mode */
+
+/*
+** Allowed values for Table.eTabType
+*/
+#define TABTYP_NORM      0     /* Ordinary table */
+#define TABTYP_VTAB      1     /* Virtual table */
+#define TABTYP_VIEW      2     /* A view */
+
+#define IsView(X)           ((X)->eTabType==TABTYP_VIEW)
+#define IsOrdinaryTable(X)  ((X)->eTabType==TABTYP_NORM)
+
+/*
+** Test to see whether or not a table is a virtual table.  This is
+** done as a macro so that it will be optimized out when virtual
+** table support is omitted from the build.
+*/
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+#  define IsVirtual(X)      ((X)->eTabType==TABTYP_VTAB)
+#  define ExprIsVtab(X)  \
+   ((X)->op==TK_COLUMN && (X)->y.pTab->eTabType==TABTYP_VTAB)
+#else
+#  define IsVirtual(X)      0
+#  define ExprIsVtab(X)     0
+#endif
+
+/*
+** Macros to determine if a column is hidden.  IsOrdinaryHiddenColumn()
+** only works for non-virtual tables (ordinary tables and views) and is
+** always false unless SQLITE_ENABLE_HIDDEN_COLUMNS is defined.  The
+** IsHiddenColumn() macro is general purpose.
+*/
+#if defined(SQLITE_ENABLE_HIDDEN_COLUMNS)
+#  define IsHiddenColumn(X)         (((X)->colFlags & COLFLAG_HIDDEN)!=0)
+#  define IsOrdinaryHiddenColumn(X) (((X)->colFlags & COLFLAG_HIDDEN)!=0)
+#elif !defined(SQLITE_OMIT_VIRTUALTABLE)
+#  define IsHiddenColumn(X)         (((X)->colFlags & COLFLAG_HIDDEN)!=0)
+#  define IsOrdinaryHiddenColumn(X) 0
+#else
+#  define IsHiddenColumn(X)         0
+#  define IsOrdinaryHiddenColumn(X) 0
+#endif
+
+
+/* Does the table have a rowid */
+#define HasRowid(X)     (((X)->tabFlags & TF_WithoutRowid)==0)
+#define VisibleRowid(X) (((X)->tabFlags & TF_NoVisibleRowid)==0)
+
+/* Macro is true if the SQLITE_ALLOW_ROWID_IN_VIEW (mis-)feature is
+** available.  By default, this macro is false
+*/
+#ifndef SQLITE_ALLOW_ROWID_IN_VIEW
+# define ViewCanHaveRowid     0
+#else
+# define ViewCanHaveRowid     (sqlite3Config.mNoVisibleRowid==0)
+#endif
+
+/*
+** Each foreign key constraint is an instance of the following structure.
+**
+** A foreign key is associated with two tables.  The "from" table is
+** the table that contains the REFERENCES clause that creates the foreign
+** key.  The "to" table is the table that is named in the REFERENCES clause.
+** Consider this example:
+**
+**     CREATE TABLE ex1(
+**       a INTEGER PRIMARY KEY,
+**       b INTEGER CONSTRAINT fk1 REFERENCES ex2(x)
+**     );
+**
+** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".
+** Equivalent names:
+**
+**     from-table == child-table
+**       to-table == parent-table
+**
+** Each REFERENCES clause generates an instance of the following structure
+** which is attached to the from-table.  The to-table need not exist when
+** the from-table is created.  The existence of the to-table is not checked.
+**
+** The list of all parents for child Table X is held at X.pFKey.
+**
+** A list of all children for a table named Z (which might not even exist)
+** is held in Schema.fkeyHash with a hash key of Z.
+*/
+struct FKey {
+  Table *pFrom;     /* Table containing the REFERENCES clause (aka: Child) */
+  FKey *pNextFrom;  /* Next FKey with the same in pFrom. Next parent of pFrom */
+  char *zTo;        /* Name of table that the key points to (aka: Parent) */
+  FKey *pNextTo;    /* Next with the same zTo. Next child of zTo. */
+  FKey *pPrevTo;    /* Previous with the same zTo */
+  int nCol;         /* Number of columns in this key */
+  /* EV: R-30323-21917 */
+  u8 isDeferred;       /* True if constraint checking is deferred till COMMIT */
+  u8 aAction[2];        /* ON DELETE and ON UPDATE actions, respectively */
+  Trigger *apTrigger[2];/* Triggers for aAction[] actions */
+  struct sColMap {      /* Mapping of columns in pFrom to columns in zTo */
+    int iFrom;            /* Index of column in pFrom */
+    char *zCol;           /* Name of column in zTo.  If NULL use PRIMARY KEY */
+  } aCol[1];            /* One entry for each of nCol columns */
+};
+
+/*
+** SQLite supports many different ways to resolve a constraint
+** error.  ROLLBACK processing means that a constraint violation
+** causes the operation in process to fail and for the current transaction
+** to be rolled back.  ABORT processing means the operation in process
+** fails and any prior changes from that one operation are backed out,
+** but the transaction is not rolled back.  FAIL processing means that
+** the operation in progress stops and returns an error code.  But prior
+** changes due to the same operation are not backed out and no rollback
+** occurs.  IGNORE means that the particular row that caused the constraint
+** error is not inserted or updated.  Processing continues and no error
+** is returned.  REPLACE means that preexisting database rows that caused
+** a UNIQUE constraint violation are removed so that the new insert or
+** update can proceed.  Processing continues and no error is reported.
+** UPDATE applies to insert operations only and means that the insert
+** is omitted and the DO UPDATE clause of an upsert is run instead.
+**
+** RESTRICT, SETNULL, SETDFLT, and CASCADE actions apply only to foreign keys.
+** RESTRICT is the same as ABORT for IMMEDIATE foreign keys and the
+** same as ROLLBACK for DEFERRED keys.  SETNULL means that the foreign
+** key is set to NULL.  SETDFLT means that the foreign key is set
+** to its default value.  CASCADE means that a DELETE or UPDATE of the
+** referenced table row is propagated into the row that holds the
+** foreign key.
+**
+** The OE_Default value is a place holder that means to use whatever
+** conflict resolution algorithm is required from context.
+**
+** The following symbolic values are used to record which type
+** of conflict resolution action to take.
+*/
+#define OE_None     0   /* There is no constraint to check */
+#define OE_Rollback 1   /* Fail the operation and rollback the transaction */
+#define OE_Abort    2   /* Back out changes but do no rollback transaction */
+#define OE_Fail     3   /* Stop the operation but leave all prior changes */
+#define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
+#define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */
+#define OE_Update   6   /* Process as a DO UPDATE in an upsert */
+#define OE_Restrict 7   /* OE_Abort for IMMEDIATE, OE_Rollback for DEFERRED */
+#define OE_SetNull  8   /* Set the foreign key value to NULL */
+#define OE_SetDflt  9   /* Set the foreign key value to its default */
+#define OE_Cascade  10  /* Cascade the changes */
+#define OE_Default  11  /* Do whatever the default action is */
+
+
+/*
+** An instance of the following structure is passed as the first
+** argument to sqlite3VdbeKeyCompare and is used to control the
+** comparison of the two index keys.
+**
+** Note that aSortOrder[] and aColl[] have nField+1 slots.  There
+** are nField slots for the columns of an index then one extra slot
+** for the rowid at the end.
+*/
+struct KeyInfo {
+  u32 nRef;           /* Number of references to this KeyInfo object */
+  u8 enc;             /* Text encoding - one of the SQLITE_UTF* values */
+  u16 nKeyField;      /* Number of key columns in the index */
+  u16 nAllField;      /* Total columns, including key plus others */
+  sqlite3 *db;        /* The database connection */
+  u8 *aSortFlags;     /* Sort order for each column. */
+  CollSeq *aColl[1];  /* Collating sequence for each term of the key */
+};
+
+/*
+** Allowed bit values for entries in the KeyInfo.aSortFlags[] array.
+*/
+#define KEYINFO_ORDER_DESC    0x01    /* DESC sort order */
+#define KEYINFO_ORDER_BIGNULL 0x02    /* NULL is larger than any other value */
+
+/*
+** This object holds a record which has been parsed out into individual
+** fields, for the purposes of doing a comparison.
+**
+** A record is an object that contains one or more fields of data.
+** Records are used to store the content of a table row and to store
+** the key of an index.  A blob encoding of a record is created by
+** the OP_MakeRecord opcode of the VDBE and is disassembled by the
+** OP_Column opcode.
+**
+** An instance of this object serves as a "key" for doing a search on
+** an index b+tree. The goal of the search is to find the entry that
+** is closed to the key described by this object.  This object might hold
+** just a prefix of the key.  The number of fields is given by
+** pKeyInfo->nField.
+**
+** The r1 and r2 fields are the values to return if this key is less than
+** or greater than a key in the btree, respectively.  These are normally
+** -1 and +1 respectively, but might be inverted to +1 and -1 if the b-tree
+** is in DESC order.
+**
+** The key comparison functions actually return default_rc when they find
+** an equals comparison.  default_rc can be -1, 0, or +1.  If there are
+** multiple entries in the b-tree with the same key (when only looking
+** at the first pKeyInfo->nFields,) then default_rc can be set to -1 to
+** cause the search to find the last match, or +1 to cause the search to
+** find the first match.
+**
+** The key comparison functions will set eqSeen to true if they ever
+** get and equal results when comparing this structure to a b-tree record.
+** When default_rc!=0, the search might end up on the record immediately
+** before the first match or immediately after the last match.  The
+** eqSeen field will indicate whether or not an exact match exists in the
+** b-tree.
+*/
+struct UnpackedRecord {
+  KeyInfo *pKeyInfo;  /* Collation and sort-order information */
+  Mem *aMem;          /* Values */
+  union {
+    char *z;            /* Cache of aMem[0].z for vdbeRecordCompareString() */
+    i64 i;              /* Cache of aMem[0].u.i for vdbeRecordCompareInt() */
+  } u;
+  int n;              /* Cache of aMem[0].n used by vdbeRecordCompareString() */
+  u16 nField;         /* Number of entries in apMem[] */
+  i8 default_rc;      /* Comparison result if keys are equal */
+  u8 errCode;         /* Error detected by xRecordCompare (CORRUPT or NOMEM) */
+  i8 r1;              /* Value to return if (lhs < rhs) */
+  i8 r2;              /* Value to return if (lhs > rhs) */
+  u8 eqSeen;          /* True if an equality comparison has been seen */
+};
+
+
+/*
+** Each SQL index is represented in memory by an
+** instance of the following structure.
+**
+** The columns of the table that are to be indexed are described
+** by the aiColumn[] field of this structure.  For example, suppose
+** we have the following table and index:
+**
+**     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
+**     CREATE INDEX Ex2 ON Ex1(c3,c1);
+**
+** In the Table structure describing Ex1, nCol==3 because there are
+** three columns in the table.  In the Index structure describing
+** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
+** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the
+** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
+** The second column to be indexed (c1) has an index of 0 in
+** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
+**
+** The Index.onError field determines whether or not the indexed columns
+** must be unique and what to do if they are not.  When Index.onError=OE_None,
+** it means this is not a unique index.  Otherwise it is a unique index
+** and the value of Index.onError indicates which conflict resolution
+** algorithm to employ when an attempt is made to insert a non-unique
+** element.
+**
+** The colNotIdxed bitmask is used in combination with SrcItem.colUsed
+** for a fast test to see if an index can serve as a covering index.
+** colNotIdxed has a 1 bit for every column of the original table that
+** is *not* available in the index.  Thus the expression
+** "colUsed & colNotIdxed" will be non-zero if the index is not a
+** covering index.  The most significant bit of of colNotIdxed will always
+** be true (note-20221022-a).  If a column beyond the 63rd column of the
+** table is used, the "colUsed & colNotIdxed" test will always be non-zero
+** and we have to assume either that the index is not covering, or use
+** an alternative (slower) algorithm to determine whether or not
+** the index is covering.
+**
+** While parsing a CREATE TABLE or CREATE INDEX statement in order to
+** generate VDBE code (as opposed to parsing one read from an sqlite_schema
+** table as part of parsing an existing database schema), transient instances
+** of this structure may be created. In this case the Index.tnum variable is
+** used to store the address of a VDBE instruction, not a database page
+** number (it cannot - the database page is not allocated until the VDBE
+** program is executed). See convertToWithoutRowidTable() for details.
+*/
+struct Index {
+  char *zName;             /* Name of this index */
+  i16 *aiColumn;           /* Which columns are used by this index.  1st is 0 */
+  LogEst *aiRowLogEst;     /* From ANALYZE: Est. rows selected by each column */
+  Table *pTable;           /* The SQL table being indexed */
+  char *zColAff;           /* String defining the affinity of each column */
+  Index *pNext;            /* The next index associated with the same table */
+  Schema *pSchema;         /* Schema containing this index */
+  u8 *aSortOrder;          /* for each column: True==DESC, False==ASC */
+  const char **azColl;     /* Array of collation sequence names for index */
+  Expr *pPartIdxWhere;     /* WHERE clause for partial indices */
+  ExprList *aColExpr;      /* Column expressions */
+  Pgno tnum;               /* DB Page containing root of this index */
+  LogEst szIdxRow;         /* Estimated average row size in bytes */
+  u16 nKeyCol;             /* Number of columns forming the key */
+  u16 nColumn;             /* Number of columns stored in the index */
+  u8 onError;              /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
+  unsigned idxType:2;      /* 0:Normal 1:UNIQUE, 2:PRIMARY KEY, 3:IPK */
+  unsigned bUnordered:1;   /* Use this index for == or IN queries only */
+  unsigned uniqNotNull:1;  /* True if UNIQUE and NOT NULL for all columns */
+  unsigned isResized:1;    /* True if resizeIndexObject() has been called */
+  unsigned isCovering:1;   /* True if this is a covering index */
+  unsigned noSkipScan:1;   /* Do not try to use skip-scan if true */
+  unsigned hasStat1:1;     /* aiRowLogEst values come from sqlite_stat1 */
+  unsigned bLowQual:1;     /* sqlite_stat1 says this is a low-quality index */
+  unsigned bNoQuery:1;     /* Do not use this index to optimize queries */
+  unsigned bAscKeyBug:1;   /* True if the bba7b69f9849b5bf bug applies */
+  unsigned bIdxRowid:1;    /* One or more of the index keys is the ROWID */
+  unsigned bHasVCol:1;     /* Index references one or more VIRTUAL columns */
+  unsigned bHasExpr:1;     /* Index contains an expression, either a literal
+                           ** expression, or a reference to a VIRTUAL column */
+#ifdef SQLITE_ENABLE_STAT4
+  int nSample;             /* Number of elements in aSample[] */
+  int mxSample;            /* Number of slots allocated to aSample[] */
+  int nSampleCol;          /* Size of IndexSample.anEq[] and so on */
+  tRowcnt *aAvgEq;         /* Average nEq values for keys not in aSample */
+  IndexSample *aSample;    /* Samples of the left-most key */
+  tRowcnt *aiRowEst;       /* Non-logarithmic stat1 data for this index */
+  tRowcnt nRowEst0;        /* Non-logarithmic number of rows in the index */
+#endif
+  Bitmask colNotIdxed;     /* Unindexed columns in pTab */
+};
+
+/*
+** Allowed values for Index.idxType
+*/
+#define SQLITE_IDXTYPE_APPDEF      0   /* Created using CREATE INDEX */
+#define SQLITE_IDXTYPE_UNIQUE      1   /* Implements a UNIQUE constraint */
+#define SQLITE_IDXTYPE_PRIMARYKEY  2   /* Is the PRIMARY KEY for the table */
+#define SQLITE_IDXTYPE_IPK         3   /* INTEGER PRIMARY KEY index */
+
+/* Return true if index X is a PRIMARY KEY index */
+#define IsPrimaryKeyIndex(X)  ((X)->idxType==SQLITE_IDXTYPE_PRIMARYKEY)
+
+/* Return true if index X is a UNIQUE index */
+#define IsUniqueIndex(X)      ((X)->onError!=OE_None)
+
+/* The Index.aiColumn[] values are normally positive integer.  But
+** there are some negative values that have special meaning:
+*/
+#define XN_ROWID     (-1)     /* Indexed column is the rowid */
+#define XN_EXPR      (-2)     /* Indexed column is an expression */
+
+/*
+** Each sample stored in the sqlite_stat4 table is represented in memory
+** using a structure of this type.  See documentation at the top of the
+** analyze.c source file for additional information.
+*/
+struct IndexSample {
+  void *p;          /* Pointer to sampled record */
+  int n;            /* Size of record in bytes */
+  tRowcnt *anEq;    /* Est. number of rows where the key equals this sample */
+  tRowcnt *anLt;    /* Est. number of rows where key is less than this sample */
+  tRowcnt *anDLt;   /* Est. number of distinct keys less than this sample */
+};
+
+/*
+** Possible values to use within the flags argument to sqlite3GetToken().
+*/
+#define SQLITE_TOKEN_QUOTED    0x1 /* Token is a quoted identifier. */
+#define SQLITE_TOKEN_KEYWORD   0x2 /* Token is a keyword. */
+
+/*
+** Each token coming out of the lexer is an instance of
+** this structure.  Tokens are also used as part of an expression.
+**
+** The memory that "z" points to is owned by other objects.  Take care
+** that the owner of the "z" string does not deallocate the string before
+** the Token goes out of scope!  Very often, the "z" points to some place
+** in the middle of the Parse.zSql text.  But it might also point to a
+** static string.
+*/
+struct Token {
+  const char *z;     /* Text of the token.  Not NULL-terminated! */
+  unsigned int n;    /* Number of characters in this token */
+};
+
+/*
+** An instance of this structure contains information needed to generate
+** code for a SELECT that contains aggregate functions.
+**
+** If Expr.op==TK_AGG_COLUMN or TK_AGG_FUNCTION then Expr.pAggInfo is a
+** pointer to this structure.  The Expr.iAgg field is the index in
+** AggInfo.aCol[] or AggInfo.aFunc[] of information needed to generate
+** code for that node.
+**
+** AggInfo.pGroupBy and AggInfo.aFunc.pExpr point to fields within the
+** original Select structure that describes the SELECT statement.  These
+** fields do not need to be freed when deallocating the AggInfo structure.
+*/
+struct AggInfo {
+  u8 directMode;          /* Direct rendering mode means take data directly
+                          ** from source tables rather than from accumulators */
+  u8 useSortingIdx;       /* In direct mode, reference the sorting index rather
+                          ** than the source table */
+  u16 nSortingColumn;     /* Number of columns in the sorting index */
+  int sortingIdx;         /* Cursor number of the sorting index */
+  int sortingIdxPTab;     /* Cursor number of pseudo-table */
+  int iFirstReg;          /* First register in range for aCol[] and aFunc[] */
+  ExprList *pGroupBy;     /* The group by clause */
+  struct AggInfo_col {    /* For each column used in source tables */
+    Table *pTab;             /* Source table */
+    Expr *pCExpr;            /* The original expression */
+    int iTable;              /* Cursor number of the source table */
+    i16 iColumn;             /* Column number within the source table */
+    i16 iSorterColumn;       /* Column number in the sorting index */
+  } *aCol;
+  int nColumn;            /* Number of used entries in aCol[] */
+  int nAccumulator;       /* Number of columns that show through to the output.
+                          ** Additional columns are used only as parameters to
+                          ** aggregate functions */
+  struct AggInfo_func {   /* For each aggregate function */
+    Expr *pFExpr;            /* Expression encoding the function */
+    FuncDef *pFunc;          /* The aggregate function implementation */
+    int iDistinct;           /* Ephemeral table used to enforce DISTINCT */
+    int iDistAddr;           /* Address of OP_OpenEphemeral */
+    int iOBTab;              /* Ephemeral table to implement ORDER BY */
+    u8 bOBPayload;           /* iOBTab has payload columns separate from key */
+    u8 bOBUnique;            /* Enforce uniqueness on iOBTab keys */
+    u8 bUseSubtype;          /* Transfer subtype info through sorter */
+  } *aFunc;
+  int nFunc;              /* Number of entries in aFunc[] */
+  u32 selId;              /* Select to which this AggInfo belongs */
+#ifdef SQLITE_DEBUG
+  Select *pSelect;        /* SELECT statement that this AggInfo supports */
+#endif
+};
+
+/*
+** Macros to compute aCol[] and aFunc[] register numbers.
+**
+** These macros should not be used prior to the call to
+** assignAggregateRegisters() that computes the value of pAggInfo->iFirstReg.
+** The assert()s that are part of this macro verify that constraint.
+*/
+#ifndef NDEBUG
+#define AggInfoColumnReg(A,I)  (assert((A)->iFirstReg),(A)->iFirstReg+(I))
+#define AggInfoFuncReg(A,I)    \
+                      (assert((A)->iFirstReg),(A)->iFirstReg+(A)->nColumn+(I))
+#else
+#define AggInfoColumnReg(A,I)  ((A)->iFirstReg+(I))
+#define AggInfoFuncReg(A,I)    \
+                      ((A)->iFirstReg+(A)->nColumn+(I))
+#endif
+
+/*
+** The datatype ynVar is a signed integer, either 16-bit or 32-bit.
+** Usually it is 16-bits.  But if SQLITE_MAX_VARIABLE_NUMBER is greater
+** than 32767 we have to make it 32-bit.  16-bit is preferred because
+** it uses less memory in the Expr object, which is a big memory user
+** in systems with lots of prepared statements.  And few applications
+** need more than about 10 or 20 variables.  But some extreme users want
+** to have prepared statements with over 32766 variables, and for them
+** the option is available (at compile-time).
+*/
+#if SQLITE_MAX_VARIABLE_NUMBER<32767
+typedef i16 ynVar;
+#else
+typedef int ynVar;
+#endif
+
+/*
+** Each node of an expression in the parse tree is an instance
+** of this structure.
+**
+** Expr.op is the opcode. The integer parser token codes are reused
+** as opcodes here. For example, the parser defines TK_GE to be an integer
+** code representing the ">=" operator. This same integer code is reused
+** to represent the greater-than-or-equal-to operator in the expression
+** tree.
+**
+** If the expression is an SQL literal (TK_INTEGER, TK_FLOAT, TK_BLOB,
+** or TK_STRING), then Expr.u.zToken contains the text of the SQL literal. If
+** the expression is a variable (TK_VARIABLE), then Expr.u.zToken contains the
+** variable name. Finally, if the expression is an SQL function (TK_FUNCTION),
+** then Expr.u.zToken contains the name of the function.
+**
+** Expr.pRight and Expr.pLeft are the left and right subexpressions of a
+** binary operator. Either or both may be NULL.
+**
+** Expr.x.pList is a list of arguments if the expression is an SQL function,
+** a CASE expression or an IN expression of the form "<lhs> IN (<y>, <z>...)".
+** Expr.x.pSelect is used if the expression is a sub-select or an expression of
+** the form "<lhs> IN (SELECT ...)". If the EP_xIsSelect bit is set in the
+** Expr.flags mask, then Expr.x.pSelect is valid. Otherwise, Expr.x.pList is
+** valid.
+**
+** An expression of the form ID or ID.ID refers to a column in a table.
+** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
+** the integer cursor number of a VDBE cursor pointing to that table and
+** Expr.iColumn is the column number for the specific column.  If the
+** expression is used as a result in an aggregate SELECT, then the
+** value is also stored in the Expr.iAgg column in the aggregate so that
+** it can be accessed after all aggregates are computed.
+**
+** If the expression is an unbound variable marker (a question mark
+** character '?' in the original SQL) then the Expr.iTable holds the index
+** number for that variable.
+**
+** If the expression is a subquery then Expr.iColumn holds an integer
+** register number containing the result of the subquery.  If the
+** subquery gives a constant result, then iTable is -1.  If the subquery
+** gives a different answer at different times during statement processing
+** then iTable is the address of a subroutine that computes the subquery.
+**
+** If the Expr is of type OP_Column, and the table it is selecting from
+** is a disk table or the "old.*" pseudo-table, then pTab points to the
+** corresponding table definition.
+**
+** ALLOCATION NOTES:
+**
+** Expr objects can use a lot of memory space in database schema.  To
+** help reduce memory requirements, sometimes an Expr object will be
+** truncated.  And to reduce the number of memory allocations, sometimes
+** two or more Expr objects will be stored in a single memory allocation,
+** together with Expr.u.zToken strings.
+**
+** If the EP_Reduced and EP_TokenOnly flags are set when
+** an Expr object is truncated.  When EP_Reduced is set, then all
+** the child Expr objects in the Expr.pLeft and Expr.pRight subtrees
+** are contained within the same memory allocation.  Note, however, that
+** the subtrees in Expr.x.pList or Expr.x.pSelect are always separately
+** allocated, regardless of whether or not EP_Reduced is set.
+*/
+struct Expr {
+  u8 op;                 /* Operation performed by this node */
+  char affExpr;          /* affinity, or RAISE type */
+  u8 op2;                /* TK_REGISTER/TK_TRUTH: original value of Expr.op
+                         ** TK_COLUMN: the value of p5 for OP_Column
+                         ** TK_AGG_FUNCTION: nesting depth
+                         ** TK_FUNCTION: NC_SelfRef flag if needs OP_PureFunc */
+#ifdef SQLITE_DEBUG
+  u8 vvaFlags;           /* Verification flags. */
+#endif
+  u32 flags;             /* Various flags.  EP_* See below */
+  union {
+    char *zToken;          /* Token value. Zero terminated and dequoted */
+    int iValue;            /* Non-negative integer value if EP_IntValue */
+  } u;
+
+  /* If the EP_TokenOnly flag is set in the Expr.flags mask, then no
+  ** space is allocated for the fields below this point. An attempt to
+  ** access them will result in a segfault or malfunction.
+  *********************************************************************/
+
+  Expr *pLeft;           /* Left subnode */
+  Expr *pRight;          /* Right subnode */
+  union {
+    ExprList *pList;     /* op = IN, EXISTS, SELECT, CASE, FUNCTION, BETWEEN */
+    Select *pSelect;     /* EP_xIsSelect and op = IN, EXISTS, SELECT */
+  } x;
+
+  /* If the EP_Reduced flag is set in the Expr.flags mask, then no
+  ** space is allocated for the fields below this point. An attempt to
+  ** access them will result in a segfault or malfunction.
+  *********************************************************************/
+
+#if SQLITE_MAX_EXPR_DEPTH>0
+  int nHeight;           /* Height of the tree headed by this node */
+#endif
+  int iTable;            /* TK_COLUMN: cursor number of table holding column
+                         ** TK_REGISTER: register number
+                         ** TK_TRIGGER: 1 -> new, 0 -> old
+                         ** EP_Unlikely:  134217728 times likelihood
+                         ** TK_IN: ephemeral table holding RHS
+                         ** TK_SELECT_COLUMN: Number of columns on the LHS
+                         ** TK_SELECT: 1st register of result vector */
+  ynVar iColumn;         /* TK_COLUMN: column index.  -1 for rowid.
+                         ** TK_VARIABLE: variable number (always >= 1).
+                         ** TK_SELECT_COLUMN: column of the result vector */
+  i16 iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
+  union {
+    int iJoin;             /* If EP_OuterON or EP_InnerON, the right table */
+    int iOfst;             /* else: start of token from start of statement */
+  } w;
+  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
+  union {
+    Table *pTab;           /* TK_COLUMN: Table containing column. Can be NULL
+                           ** for a column of an index on an expression */
+    Window *pWin;          /* EP_WinFunc: Window/Filter defn for a function */
+    struct {               /* TK_IN, TK_SELECT, and TK_EXISTS */
+      int iAddr;             /* Subroutine entry address */
+      int regReturn;         /* Register used to hold return address */
+    } sub;
+  } y;
+};
+
+/* The following are the meanings of bits in the Expr.flags field.
+** Value restrictions:
+**
+**          EP_Agg == NC_HasAgg == SF_HasAgg
+**          EP_Win == NC_HasWin
+*/
+#define EP_OuterON    0x000001 /* Originates in ON/USING clause of outer join */
+#define EP_InnerON    0x000002 /* Originates in ON/USING of an inner join */
+#define EP_Distinct   0x000004 /* Aggregate function with DISTINCT keyword */
+#define EP_HasFunc    0x000008 /* Contains one or more functions of any kind */
+#define EP_Agg        0x000010 /* Contains one or more aggregate functions */
+#define EP_FixedCol   0x000020 /* TK_Column with a known fixed value */
+#define EP_VarSelect  0x000040 /* pSelect is correlated, not constant */
+#define EP_DblQuoted  0x000080 /* token.z was originally in "..." */
+#define EP_InfixFunc  0x000100 /* True for an infix function: LIKE, GLOB, etc */
+#define EP_Collate    0x000200 /* Tree contains a TK_COLLATE operator */
+#define EP_Commuted   0x000400 /* Comparison operator has been commuted */
+#define EP_IntValue   0x000800 /* Integer value contained in u.iValue */
+#define EP_xIsSelect  0x001000 /* x.pSelect is valid (otherwise x.pList is) */
+#define EP_Skip       0x002000 /* Operator does not contribute to affinity */
+#define EP_Reduced    0x004000 /* Expr struct EXPR_REDUCEDSIZE bytes only */
+#define EP_Win        0x008000 /* Contains window functions */
+#define EP_TokenOnly  0x010000 /* Expr struct EXPR_TOKENONLYSIZE bytes only */
+#define EP_FullSize   0x020000 /* Expr structure must remain full sized */
+#define EP_IfNullRow  0x040000 /* The TK_IF_NULL_ROW opcode */
+#define EP_Unlikely   0x080000 /* unlikely() or likelihood() function */
+#define EP_ConstFunc  0x100000 /* A SQLITE_FUNC_CONSTANT or _SLOCHNG function */
+#define EP_CanBeNull  0x200000 /* Can be null despite NOT NULL constraint */
+#define EP_Subquery   0x400000 /* Tree contains a TK_SELECT operator */
+#define EP_Leaf       0x800000 /* Expr.pLeft, .pRight, .u.pSelect all NULL */
+#define EP_WinFunc   0x1000000 /* TK_FUNCTION with Expr.y.pWin set */
+#define EP_Subrtn    0x2000000 /* Uses Expr.y.sub. TK_IN, _SELECT, or _EXISTS */
+#define EP_Quoted    0x4000000 /* TK_ID was originally quoted */
+#define EP_Static    0x8000000 /* Held in memory not obtained from malloc() */
+#define EP_IsTrue   0x10000000 /* Always has boolean value of TRUE */
+#define EP_IsFalse  0x20000000 /* Always has boolean value of FALSE */
+#define EP_FromDDL  0x40000000 /* Originates from sqlite_schema */
+#define EP_SubtArg  0x80000000 /* Is argument to SQLITE_SUBTYPE function */
+
+/* The EP_Propagate mask is a set of properties that automatically propagate
+** upwards into parent nodes.
+*/
+#define EP_Propagate (EP_Collate|EP_Subquery|EP_HasFunc)
+
+/* Macros can be used to test, set, or clear bits in the
+** Expr.flags field.
+*/
+#define ExprHasProperty(E,P)     (((E)->flags&(P))!=0)
+#define ExprHasAllProperty(E,P)  (((E)->flags&(P))==(P))
+#define ExprSetProperty(E,P)     (E)->flags|=(P)
+#define ExprClearProperty(E,P)   (E)->flags&=~(P)
+#define ExprAlwaysTrue(E)   (((E)->flags&(EP_OuterON|EP_IsTrue))==EP_IsTrue)
+#define ExprAlwaysFalse(E)  (((E)->flags&(EP_OuterON|EP_IsFalse))==EP_IsFalse)
+#define ExprIsFullSize(E)   (((E)->flags&(EP_Reduced|EP_TokenOnly))==0)
+
+/* Macros used to ensure that the correct members of unions are accessed
+** in Expr.
+*/
+#define ExprUseUToken(E)    (((E)->flags&EP_IntValue)==0)
+#define ExprUseUValue(E)    (((E)->flags&EP_IntValue)!=0)
+#define ExprUseWOfst(E)     (((E)->flags&(EP_InnerON|EP_OuterON))==0)
+#define ExprUseWJoin(E)     (((E)->flags&(EP_InnerON|EP_OuterON))!=0)
+#define ExprUseXList(E)     (((E)->flags&EP_xIsSelect)==0)
+#define ExprUseXSelect(E)   (((E)->flags&EP_xIsSelect)!=0)
+#define ExprUseYTab(E)      (((E)->flags&(EP_WinFunc|EP_Subrtn))==0)
+#define ExprUseYWin(E)      (((E)->flags&EP_WinFunc)!=0)
+#define ExprUseYSub(E)      (((E)->flags&EP_Subrtn)!=0)
+
+/* Flags for use with Expr.vvaFlags
+*/
+#define EP_NoReduce   0x01  /* Cannot EXPRDUP_REDUCE this Expr */
+#define EP_Immutable  0x02  /* Do not change this Expr node */
+
+/* The ExprSetVVAProperty() macro is used for Verification, Validation,
+** and Accreditation only.  It works like ExprSetProperty() during VVA
+** processes but is a no-op for delivery.
+*/
+#ifdef SQLITE_DEBUG
+# define ExprSetVVAProperty(E,P)   (E)->vvaFlags|=(P)
+# define ExprHasVVAProperty(E,P)   (((E)->vvaFlags&(P))!=0)
+# define ExprClearVVAProperties(E) (E)->vvaFlags = 0
+#else
+# define ExprSetVVAProperty(E,P)
+# define ExprHasVVAProperty(E,P)   0
+# define ExprClearVVAProperties(E)
+#endif
+
+/*
+** Macros to determine the number of bytes required by a normal Expr
+** struct, an Expr struct with the EP_Reduced flag set in Expr.flags
+** and an Expr struct with the EP_TokenOnly flag set.
+*/
+#define EXPR_FULLSIZE           sizeof(Expr)           /* Full size */
+#define EXPR_REDUCEDSIZE        offsetof(Expr,iTable)  /* Common features */
+#define EXPR_TOKENONLYSIZE      offsetof(Expr,pLeft)   /* Fewer features */
+
+/*
+** Flags passed to the sqlite3ExprDup() function. See the header comment
+** above sqlite3ExprDup() for details.
+*/
+#define EXPRDUP_REDUCE         0x0001  /* Used reduced-size Expr nodes */
+
+/*
+** True if the expression passed as an argument was a function with
+** an OVER() clause (a window function).
+*/
+#ifdef SQLITE_OMIT_WINDOWFUNC
+# define IsWindowFunc(p) 0
+#else
+# define IsWindowFunc(p) ( \
+    ExprHasProperty((p), EP_WinFunc) && p->y.pWin->eFrmType!=TK_FILTER \
+ )
+#endif
+
+/*
+** A list of expressions.  Each expression may optionally have a
+** name.  An expr/name combination can be used in several ways, such
+** as the list of "expr AS ID" fields following a "SELECT" or in the
+** list of "ID = expr" items in an UPDATE.  A list of expressions can
+** also be used as the argument to a function, in which case the a.zName
+** field is not used.
+**
+** In order to try to keep memory usage down, the Expr.a.zEName field
+** is used for multiple purposes:
+**
+**     eEName          Usage
+**    ----------       -------------------------
+**    ENAME_NAME       (1) the AS of result set column
+**                     (2) COLUMN= of an UPDATE
+**
+**    ENAME_TAB        DB.TABLE.NAME used to resolve names
+**                     of subqueries
+**
+**    ENAME_SPAN       Text of the original result set
+**                     expression.
+*/
+struct ExprList {
+  int nExpr;             /* Number of expressions on the list */
+  int nAlloc;            /* Number of a[] slots allocated */
+  struct ExprList_item { /* For each expression in the list */
+    Expr *pExpr;            /* The parse tree for this expression */
+    char *zEName;           /* Token associated with this expression */
+    struct {
+      u8 sortFlags;           /* Mask of KEYINFO_ORDER_* flags */
+      unsigned eEName :2;     /* Meaning of zEName */
+      unsigned done :1;       /* Indicates when processing is finished */
+      unsigned reusable :1;   /* Constant expression is reusable */
+      unsigned bSorterRef :1; /* Defer evaluation until after sorting */
+      unsigned bNulls :1;     /* True if explicit "NULLS FIRST/LAST" */
+      unsigned bUsed :1;      /* This column used in a SF_NestedFrom subquery */
+      unsigned bUsingTerm:1;  /* Term from the USING clause of a NestedFrom */
+      unsigned bNoExpand: 1;  /* Term is an auxiliary in NestedFrom and should
+                              ** not be expanded by "*" in parent queries */
+    } fg;
+    union {
+      struct {             /* Used by any ExprList other than Parse.pConsExpr */
+        u16 iOrderByCol;      /* For ORDER BY, column number in result set */
+        u16 iAlias;           /* Index into Parse.aAlias[] for zName */
+      } x;
+      int iConstExprReg;   /* Register in which Expr value is cached. Used only
+                           ** by Parse.pConstExpr */
+    } u;
+  } a[1];                  /* One slot for each expression in the list */
+};
+
+/*
+** Allowed values for Expr.a.eEName
+*/
+#define ENAME_NAME  0       /* The AS clause of a result set */
+#define ENAME_SPAN  1       /* Complete text of the result set expression */
+#define ENAME_TAB   2       /* "DB.TABLE.NAME" for the result set */
+#define ENAME_ROWID 3       /* "DB.TABLE._rowid_" for * expansion of rowid */
+
+/*
+** An instance of this structure can hold a simple list of identifiers,
+** such as the list "a,b,c" in the following statements:
+**
+**      INSERT INTO t(a,b,c) VALUES ...;
+**      CREATE INDEX idx ON t(a,b,c);
+**      CREATE TRIGGER trig BEFORE UPDATE ON t(a,b,c) ...;
+**
+** The IdList.a.idx field is used when the IdList represents the list of
+** column names after a table name in an INSERT statement.  In the statement
+**
+**     INSERT INTO t(a,b,c) ...
+**
+** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
+*/
+struct IdList {
+  int nId;         /* Number of identifiers on the list */
+  struct IdList_item {
+    char *zName;      /* Name of the identifier */
+  } a[1];
+};
+
+/*
+** Allowed values for IdList.eType, which determines which value of the a.u4
+** is valid.
+*/
+#define EU4_NONE   0   /* Does not use IdList.a.u4 */
+#define EU4_IDX    1   /* Uses IdList.a.u4.idx */
+#define EU4_EXPR   2   /* Uses IdList.a.u4.pExpr -- NOT CURRENTLY USED */
+
+/*
+** Details of the implementation of a subquery.
+*/
+struct Subquery {
+  Select *pSelect;  /* A SELECT statement used in place of a table name */
+  int addrFillSub;  /* Address of subroutine to initialize a subquery */
+  int regReturn;    /* Register holding return address of addrFillSub */
+  int regResult;    /* Registers holding results of a co-routine */
+};
+
+/*
+** The SrcItem object represents a single term in the FROM clause of a query.
+** The SrcList object is mostly an array of SrcItems.
+**
+** The jointype starts out showing the join type between the current table
+** and the next table on the list.  The parser builds the list this way.
+** But sqlite3SrcListShiftJoinType() later shifts the jointypes so that each
+** jointype expresses the join between the table and the previous table.
+**
+** In the colUsed field, the high-order bit (bit 63) is set if the table
+** contains more than 63 columns and the 64-th or later column is used.
+**
+** Aggressive use of "union" helps keep the size of the object small.  This
+** has been shown to boost performance, in addition to saving memory.
+** Access to union elements is gated by the following rules which should
+** always be checked, either by an if-statement or by an assert().
+**
+**    Field              Only access if this is true
+**    ---------------    -----------------------------------
+**    u1.zIndexedBy      fg.isIndexedBy
+**    u1.pFuncArg        fg.isTabFunc
+**    u1.nRow            !fg.isTabFunc  && !fg.isIndexedBy
+**
+**    u2.pIBIndex        fg.isIndexedBy
+**    u2.pCteUse         fg.isCte
+**
+**    u3.pOn             !fg.isUsing
+**    u3.pUsing          fg.isUsing
+**
+**    u4.zDatabase       !fg.fixedSchema && !fg.isSubquery
+**    u4.pSchema         fg.fixedSchema
+**    u4.pSubq           fg.isSubquery
+**
+** See also the sqlite3SrcListDelete() routine for assert() statements that
+** check invariants on the fields of this object, especially the flags
+** inside the fg struct.
+*/
+struct SrcItem {
+  char *zName;      /* Name of the table */
+  char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
+  Table *pSTab;     /* Table object for zName. Mnemonic: Srcitem-TABle */
+  struct {
+    u8 jointype;      /* Type of join between this table and the previous */
+    unsigned notIndexed :1;    /* True if there is a NOT INDEXED clause */
+    unsigned isIndexedBy :1;   /* True if there is an INDEXED BY clause */
+    unsigned isSubquery :1;    /* True if this term is a subquery */
+    unsigned isTabFunc :1;     /* True if table-valued-function syntax */
+    unsigned isCorrelated :1;  /* True if sub-query is correlated */
+    unsigned isMaterialized:1; /* This is a materialized view */
+    unsigned viaCoroutine :1;  /* Implemented as a co-routine */
+    unsigned isRecursive :1;   /* True for recursive reference in WITH */
+    unsigned fromDDL :1;       /* Comes from sqlite_schema */
+    unsigned isCte :1;         /* This is a CTE */
+    unsigned notCte :1;        /* This item may not match a CTE */
+    unsigned isUsing :1;       /* u3.pUsing is valid */
+    unsigned isOn :1;          /* u3.pOn was once valid and non-NULL */
+    unsigned isSynthUsing :1;  /* u3.pUsing is synthesized from NATURAL */
+    unsigned isNestedFrom :1;  /* pSelect is a SF_NestedFrom subquery */
+    unsigned rowidUsed :1;     /* The ROWID of this table is referenced */
+    unsigned fixedSchema :1;   /* Uses u4.pSchema, not u4.zDatabase */
+    unsigned hadSchema :1;     /* Had u4.zDatabase before u4.pSchema */
+  } fg;
+  int iCursor;      /* The VDBE cursor number used to access this table */
+  Bitmask colUsed;  /* Bit N set if column N used. Details above for N>62 */
+  union {
+    char *zIndexedBy;    /* Identifier from "INDEXED BY <zIndex>" clause */
+    ExprList *pFuncArg;  /* Arguments to table-valued-function */
+    u32 nRow;            /* Number of rows in a VALUES clause */
+  } u1;
+  union {
+    Index *pIBIndex;  /* Index structure corresponding to u1.zIndexedBy */
+    CteUse *pCteUse;  /* CTE Usage info when fg.isCte is true */
+  } u2;
+  union {
+    Expr *pOn;        /* fg.isUsing==0 =>  The ON clause of a join */
+    IdList *pUsing;   /* fg.isUsing==1 =>  The USING clause of a join */
+  } u3;
+  union {
+    Schema *pSchema;  /* Schema to which this item is fixed */
+    char *zDatabase;  /* Name of database holding this table */
+    Subquery *pSubq;  /* Description of a subquery */
+  } u4;
+};
+
+/*
+** The OnOrUsing object represents either an ON clause or a USING clause.
+** It can never be both at the same time, but it can be neither.
+*/
+struct OnOrUsing {
+  Expr *pOn;         /* The ON clause of a join */
+  IdList *pUsing;    /* The USING clause of a join */
+};
+
+/*
+** This object represents one or more tables that are the source of
+** content for an SQL statement.  For example, a single SrcList object
+** is used to hold the FROM clause of a SELECT statement.  SrcList also
+** represents the target tables for DELETE, INSERT, and UPDATE statements.
+**
+*/
+struct SrcList {
+  int nSrc;        /* Number of tables or subqueries in the FROM clause */
+  u32 nAlloc;      /* Number of entries allocated in a[] below */
+  SrcItem a[1];    /* One entry for each identifier on the list */
+};
+
+/*
+** Permitted values of the SrcList.a.jointype field
+*/
+#define JT_INNER     0x01    /* Any kind of inner or cross join */
+#define JT_CROSS     0x02    /* Explicit use of the CROSS keyword */
+#define JT_NATURAL   0x04    /* True for a "natural" join */
+#define JT_LEFT      0x08    /* Left outer join */
+#define JT_RIGHT     0x10    /* Right outer join */
+#define JT_OUTER     0x20    /* The "OUTER" keyword is present */
+#define JT_LTORJ     0x40    /* One of the LEFT operands of a RIGHT JOIN
+                             ** Mnemonic: Left Table Of Right Join */
+#define JT_ERROR     0x80    /* unknown or unsupported join type */
+
+/*
+** Flags appropriate for the wctrlFlags parameter of sqlite3WhereBegin()
+** and the WhereInfo.wctrlFlags member.
+**
+** Value constraints (enforced via assert()):
+**     WHERE_USE_LIMIT  == SF_FixedLimit
+*/
+#define WHERE_ORDERBY_NORMAL   0x0000 /* No-op */
+#define WHERE_ORDERBY_MIN      0x0001 /* ORDER BY processing for min() func */
+#define WHERE_ORDERBY_MAX      0x0002 /* ORDER BY processing for max() func */
+#define WHERE_ONEPASS_DESIRED  0x0004 /* Want to do one-pass UPDATE/DELETE */
+#define WHERE_ONEPASS_MULTIROW 0x0008 /* ONEPASS is ok with multiple rows */
+#define WHERE_DUPLICATES_OK    0x0010 /* Ok to return a row more than once */
+#define WHERE_OR_SUBCLAUSE     0x0020 /* Processing a sub-WHERE as part of
+                                      ** the OR optimization  */
+#define WHERE_GROUPBY          0x0040 /* pOrderBy is really a GROUP BY */
+#define WHERE_DISTINCTBY       0x0080 /* pOrderby is really a DISTINCT clause */
+#define WHERE_WANT_DISTINCT    0x0100 /* All output needs to be distinct */
+#define WHERE_SORTBYGROUP      0x0200 /* Support sqlite3WhereIsSorted() */
+#define WHERE_AGG_DISTINCT     0x0400 /* Query is "SELECT agg(DISTINCT ...)" */
+#define WHERE_ORDERBY_LIMIT    0x0800 /* ORDERBY+LIMIT on the inner loop */
+#define WHERE_RIGHT_JOIN       0x1000 /* Processing a RIGHT JOIN */
+#define WHERE_KEEP_ALL_JOINS   0x2000 /* Do not do the omit-noop-join opt */
+#define WHERE_USE_LIMIT        0x4000 /* Use the LIMIT in cost estimates */
+                        /*     0x8000    not currently used */
+
+/* Allowed return values from sqlite3WhereIsDistinct()
+*/
+#define WHERE_DISTINCT_NOOP      0  /* DISTINCT keyword not used */
+#define WHERE_DISTINCT_UNIQUE    1  /* No duplicates */
+#define WHERE_DISTINCT_ORDERED   2  /* All duplicates are adjacent */
+#define WHERE_DISTINCT_UNORDERED 3  /* Duplicates are scattered */
+
+/*
+** A NameContext defines a context in which to resolve table and column
+** names.  The context consists of a list of tables (the pSrcList) field and
+** a list of named expression (pEList).  The named expression list may
+** be NULL.  The pSrc corresponds to the FROM clause of a SELECT or
+** to the table being operated on by INSERT, UPDATE, or DELETE.  The
+** pEList corresponds to the result set of a SELECT and is NULL for
+** other statements.
+**
+** NameContexts can be nested.  When resolving names, the inner-most
+** context is searched first.  If no match is found, the next outer
+** context is checked.  If there is still no match, the next context
+** is checked.  This process continues until either a match is found
+** or all contexts are check.  When a match is found, the nRef member of
+** the context containing the match is incremented.
+**
+** Each subquery gets a new NameContext.  The pNext field points to the
+** NameContext in the parent query.  Thus the process of scanning the
+** NameContext list corresponds to searching through successively outer
+** subqueries looking for a match.
+*/
+struct NameContext {
+  Parse *pParse;       /* The parser */
+  SrcList *pSrcList;   /* One or more tables used to resolve names */
+  union {
+    ExprList *pEList;    /* Optional list of result-set columns */
+    AggInfo *pAggInfo;   /* Information about aggregates at this level */
+    Upsert *pUpsert;     /* ON CONFLICT clause information from an upsert */
+    int iBaseReg;        /* For TK_REGISTER when parsing RETURNING */
+  } uNC;
+  NameContext *pNext;  /* Next outer name context.  NULL for outermost */
+  int nRef;            /* Number of names resolved by this context */
+  int nNcErr;          /* Number of errors encountered while resolving names */
+  int ncFlags;         /* Zero or more NC_* flags defined below */
+  u32 nNestedSelect;   /* Number of nested selects using this NC */
+  Select *pWinSelect;  /* SELECT statement for any window functions */
+};
+
+/*
+** Allowed values for the NameContext, ncFlags field.
+**
+** Value constraints (all checked via assert()):
+**    NC_HasAgg    == SF_HasAgg       == EP_Agg
+**    NC_MinMaxAgg == SF_MinMaxAgg    == SQLITE_FUNC_MINMAX
+**    NC_OrderAgg  == SF_OrderByReqd  == SQLITE_FUNC_ANYORDER
+**    NC_HasWin    == EP_Win
+**
+*/
+#define NC_AllowAgg  0x000001 /* Aggregate functions are allowed here */
+#define NC_PartIdx   0x000002 /* True if resolving a partial index WHERE */
+#define NC_IsCheck   0x000004 /* True if resolving a CHECK constraint */
+#define NC_GenCol    0x000008 /* True for a GENERATED ALWAYS AS clause */
+#define NC_HasAgg    0x000010 /* One or more aggregate functions seen */
+#define NC_IdxExpr   0x000020 /* True if resolving columns of CREATE INDEX */
+#define NC_SelfRef   0x00002e /* Combo: PartIdx, isCheck, GenCol, and IdxExpr */
+#define NC_Subquery  0x000040 /* A subquery has been seen */
+#define NC_UEList    0x000080 /* True if uNC.pEList is used */
+#define NC_UAggInfo  0x000100 /* True if uNC.pAggInfo is used */
+#define NC_UUpsert   0x000200 /* True if uNC.pUpsert is used */
+#define NC_UBaseReg  0x000400 /* True if uNC.iBaseReg is used */
+#define NC_MinMaxAgg 0x001000 /* min/max aggregates seen.  See note above */
+/*                   0x002000 // available for reuse */
+#define NC_AllowWin  0x004000 /* Window functions are allowed here */
+#define NC_HasWin    0x008000 /* One or more window functions seen */
+#define NC_IsDDL     0x010000 /* Resolving names in a CREATE statement */
+#define NC_InAggFunc 0x020000 /* True if analyzing arguments to an agg func */
+#define NC_FromDDL   0x040000 /* SQL text comes from sqlite_schema */
+#define NC_NoSelect  0x080000 /* Do not descend into sub-selects */
+#define NC_Where     0x100000 /* Processing WHERE clause of a SELECT */
+#define NC_OrderAgg 0x8000000 /* Has an aggregate other than count/min/max */
+
+/*
+** An instance of the following object describes a single ON CONFLICT
+** clause in an upsert.
+**
+** The pUpsertTarget field is only set if the ON CONFLICT clause includes
+** conflict-target clause.  (In "ON CONFLICT(a,b)" the "(a,b)" is the
+** conflict-target clause.)  The pUpsertTargetWhere is the optional
+** WHERE clause used to identify partial unique indexes.
+**
+** pUpsertSet is the list of column=expr terms of the UPDATE statement.
+** The pUpsertSet field is NULL for a ON CONFLICT DO NOTHING.  The
+** pUpsertWhere is the WHERE clause for the UPDATE and is NULL if the
+** WHERE clause is omitted.
+*/
+struct Upsert {
+  ExprList *pUpsertTarget;  /* Optional description of conflict target */
+  Expr *pUpsertTargetWhere; /* WHERE clause for partial index targets */
+  ExprList *pUpsertSet;     /* The SET clause from an ON CONFLICT UPDATE */
+  Expr *pUpsertWhere;       /* WHERE clause for the ON CONFLICT UPDATE */
+  Upsert *pNextUpsert;      /* Next ON CONFLICT clause in the list */
+  u8 isDoUpdate;            /* True for DO UPDATE.  False for DO NOTHING */
+  u8 isDup;                 /* True if 2nd or later with same pUpsertIdx */
+  /* Above this point is the parse tree for the ON CONFLICT clauses.
+  ** The next group of fields stores intermediate data. */
+  void *pToFree;            /* Free memory when deleting the Upsert object */
+  /* All fields above are owned by the Upsert object and must be freed
+  ** when the Upsert is destroyed.  The fields below are used to transfer
+  ** information from the INSERT processing down into the UPDATE processing
+  ** while generating code.  The fields below are owned by the INSERT
+  ** statement and will be freed by INSERT processing. */
+  Index *pUpsertIdx;        /* UNIQUE constraint specified by pUpsertTarget */
+  SrcList *pUpsertSrc;      /* Table to be updated */
+  int regData;              /* First register holding array of VALUES */
+  int iDataCur;             /* Index of the data cursor */
+  int iIdxCur;              /* Index of the first index cursor */
+};
+
+/*
+** An instance of the following structure contains all information
+** needed to generate code for a single SELECT statement.
+**
+** See the header comment on the computeLimitRegisters() routine for a
+** detailed description of the meaning of the iLimit and iOffset fields.
+**
+** addrOpenEphm[] entries contain the address of OP_OpenEphemeral opcodes.
+** These addresses must be stored so that we can go back and fill in
+** the P4_KEYINFO and P2 parameters later.  Neither the KeyInfo nor
+** the number of columns in P2 can be computed at the same time
+** as the OP_OpenEphm instruction is coded because not
+** enough information about the compound query is known at that point.
+** The KeyInfo for addrOpenTran[0] and [1] contains collating sequences
+** for the result set.  The KeyInfo for addrOpenEphm[2] contains collating
+** sequences for the ORDER BY clause.
+*/
+struct Select {
+  u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
+  LogEst nSelectRow;     /* Estimated number of result rows */
+  u32 selFlags;          /* Various SF_* values */
+  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
+  u32 selId;             /* Unique identifier number for this SELECT */
+  int addrOpenEphm[2];   /* OP_OpenEphem opcodes related to this select */
+  ExprList *pEList;      /* The fields of the result */
+  SrcList *pSrc;         /* The FROM clause */
+  Expr *pWhere;          /* The WHERE clause */
+  ExprList *pGroupBy;    /* The GROUP BY clause */
+  Expr *pHaving;         /* The HAVING clause */
+  ExprList *pOrderBy;    /* The ORDER BY clause */
+  Select *pPrior;        /* Prior select in a compound select statement */
+  Select *pNext;         /* Next select to the left in a compound */
+  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
+  With *pWith;           /* WITH clause attached to this select. Or NULL. */
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  Window *pWin;          /* List of window functions */
+  Window *pWinDefn;      /* List of named window definitions */
+#endif
+};
+
+/*
+** Allowed values for Select.selFlags.  The "SF" prefix stands for
+** "Select Flag".
+**
+** Value constraints (all checked via assert())
+**     SF_HasAgg      == NC_HasAgg
+**     SF_MinMaxAgg   == NC_MinMaxAgg     == SQLITE_FUNC_MINMAX
+**     SF_OrderByReqd == NC_OrderAgg      == SQLITE_FUNC_ANYORDER
+**     SF_FixedLimit  == WHERE_USE_LIMIT
+*/
+#define SF_Distinct      0x0000001 /* Output should be DISTINCT */
+#define SF_All           0x0000002 /* Includes the ALL keyword */
+#define SF_Resolved      0x0000004 /* Identifiers have been resolved */
+#define SF_Aggregate     0x0000008 /* Contains agg functions or a GROUP BY */
+#define SF_HasAgg        0x0000010 /* Contains aggregate functions */
+#define SF_UsesEphemeral 0x0000020 /* Uses the OpenEphemeral opcode */
+#define SF_Expanded      0x0000040 /* sqlite3SelectExpand() called on this */
+#define SF_HasTypeInfo   0x0000080 /* FROM subqueries have Table metadata */
+#define SF_Compound      0x0000100 /* Part of a compound query */
+#define SF_Values        0x0000200 /* Synthesized from VALUES clause */
+#define SF_MultiValue    0x0000400 /* Single VALUES term with multiple rows */
+#define SF_NestedFrom    0x0000800 /* Part of a parenthesized FROM clause */
+#define SF_MinMaxAgg     0x0001000 /* Aggregate containing min() or max() */
+#define SF_Recursive     0x0002000 /* The recursive part of a recursive CTE */
+#define SF_FixedLimit    0x0004000 /* nSelectRow set by a constant LIMIT */
+#define SF_MaybeConvert  0x0008000 /* Need convertCompoundSelectToSubquery() */
+#define SF_Converted     0x0010000 /* By convertCompoundSelectToSubquery() */
+#define SF_IncludeHidden 0x0020000 /* Include hidden columns in output */
+#define SF_ComplexResult 0x0040000 /* Result contains subquery or function */
+#define SF_WhereBegin    0x0080000 /* Really a WhereBegin() call.  Debug Only */
+#define SF_WinRewrite    0x0100000 /* Window function rewrite accomplished */
+#define SF_View          0x0200000 /* SELECT statement is a view */
+#define SF_NoopOrderBy   0x0400000 /* ORDER BY is ignored for this query */
+#define SF_UFSrcCheck    0x0800000 /* Check pSrc as required by UPDATE...FROM */
+#define SF_PushDown      0x1000000 /* Modified by WHERE-clause push-down opt */
+#define SF_MultiPart     0x2000000 /* Has multiple incompatible PARTITIONs */
+#define SF_CopyCte       0x4000000 /* SELECT statement is a copy of a CTE */
+#define SF_OrderByReqd   0x8000000 /* The ORDER BY clause may not be omitted */
+#define SF_UpdateFrom   0x10000000 /* Query originates with UPDATE FROM */
+#define SF_Correlated   0x20000000 /* True if references the outer context */
+
+/* True if SrcItem X is a subquery that has SF_NestedFrom */
+#define IsNestedFrom(X) \
+   ((X)->fg.isSubquery && \
+    ((X)->u4.pSubq->pSelect->selFlags&SF_NestedFrom)!=0)
+
+/*
+** The results of a SELECT can be distributed in several ways, as defined
+** by one of the following macros.  The "SRT" prefix means "SELECT Result
+** Type".
+**
+**     SRT_Union       Store results as a key in a temporary index
+**                     identified by pDest->iSDParm.
+**
+**     SRT_Except      Remove results from the temporary index pDest->iSDParm.
+**
+**     SRT_Exists      Store a 1 in memory cell pDest->iSDParm if the result
+**                     set is not empty.
+**
+**     SRT_Discard     Throw the results away.  This is used by SELECT
+**                     statements within triggers whose only purpose is
+**                     the side-effects of functions.
+**
+**     SRT_Output      Generate a row of output (using the OP_ResultRow
+**                     opcode) for each row in the result set.
+**
+**     SRT_Mem         Only valid if the result is a single column.
+**                     Store the first column of the first result row
+**                     in register pDest->iSDParm then abandon the rest
+**                     of the query.  This destination implies "LIMIT 1".
+**
+**     SRT_Set         The result must be a single column.  Store each
+**                     row of result as the key in table pDest->iSDParm.
+**                     Apply the affinity pDest->affSdst before storing
+**                     results.  if pDest->iSDParm2 is positive, then it is
+**                     a register holding a Bloom filter for the IN operator
+**                     that should be populated in addition to the
+**                     pDest->iSDParm table.  This SRT is used to
+**                     implement "IN (SELECT ...)".
+**
+**     SRT_EphemTab    Create an temporary table pDest->iSDParm and store
+**                     the result there. The cursor is left open after
+**                     returning.  This is like SRT_Table except that
+**                     this destination uses OP_OpenEphemeral to create
+**                     the table first.
+**
+**     SRT_Coroutine   Generate a co-routine that returns a new row of
+**                     results each time it is invoked.  The entry point
+**                     of the co-routine is stored in register pDest->iSDParm
+**                     and the result row is stored in pDest->nDest registers
+**                     starting with pDest->iSdst.
+**
+**     SRT_Table       Store results in temporary table pDest->iSDParm.
+**     SRT_Fifo        This is like SRT_EphemTab except that the table
+**                     is assumed to already be open.  SRT_Fifo has
+**                     the additional property of being able to ignore
+**                     the ORDER BY clause.
+**
+**     SRT_DistFifo    Store results in a temporary table pDest->iSDParm.
+**                     But also use temporary table pDest->iSDParm+1 as
+**                     a record of all prior results and ignore any duplicate
+**                     rows.  Name means:  "Distinct Fifo".
+**
+**     SRT_Queue       Store results in priority queue pDest->iSDParm (really
+**                     an index).  Append a sequence number so that all entries
+**                     are distinct.
+**
+**     SRT_DistQueue   Store results in priority queue pDest->iSDParm only if
+**                     the same record has never been stored before.  The
+**                     index at pDest->iSDParm+1 hold all prior stores.
+**
+**     SRT_Upfrom      Store results in the temporary table already opened by
+**                     pDest->iSDParm. If (pDest->iSDParm<0), then the temp
+**                     table is an intkey table - in this case the first
+**                     column returned by the SELECT is used as the integer
+**                     key. If (pDest->iSDParm>0), then the table is an index
+**                     table. (pDest->iSDParm) is the number of key columns in
+**                     each index record in this case.
+*/
+#define SRT_Union        1  /* Store result as keys in an index */
+#define SRT_Except       2  /* Remove result from a UNION index */
+#define SRT_Exists       3  /* Store 1 if the result is not empty */
+#define SRT_Discard      4  /* Do not save the results anywhere */
+#define SRT_DistFifo     5  /* Like SRT_Fifo, but unique results only */
+#define SRT_DistQueue    6  /* Like SRT_Queue, but unique results only */
+
+/* The DISTINCT clause is ignored for all of the above.  Not that
+** IgnorableDistinct() implies IgnorableOrderby() */
+#define IgnorableDistinct(X) ((X->eDest)<=SRT_DistQueue)
+
+#define SRT_Queue        7  /* Store result in an queue */
+#define SRT_Fifo         8  /* Store result as data with an automatic rowid */
+
+/* The ORDER BY clause is ignored for all of the above */
+#define IgnorableOrderby(X) ((X->eDest)<=SRT_Fifo)
+
+#define SRT_Output       9  /* Output each row of result */
+#define SRT_Mem         10  /* Store result in a memory cell */
+#define SRT_Set         11  /* Store results as keys in an index */
+#define SRT_EphemTab    12  /* Create transient tab and store like SRT_Table */
+#define SRT_Coroutine   13  /* Generate a single row of result */
+#define SRT_Table       14  /* Store result as data with an automatic rowid */
+#define SRT_Upfrom      15  /* Store result as data with rowid */
+
+/*
+** An instance of this object describes where to put of the results of
+** a SELECT statement.
+*/
+struct SelectDest {
+  u8 eDest;            /* How to dispose of the results.  One of SRT_* above. */
+  int iSDParm;         /* A parameter used by the eDest disposal method */
+  int iSDParm2;        /* A second parameter for the eDest disposal method */
+  int iSdst;           /* Base register where results are written */
+  int nSdst;           /* Number of registers allocated */
+  char *zAffSdst;      /* Affinity used for SRT_Set */
+  ExprList *pOrderBy;  /* Key columns for SRT_Queue and SRT_DistQueue */
+};
+
+/*
+** During code generation of statements that do inserts into AUTOINCREMENT
+** tables, the following information is attached to the Table.u.autoInc.p
+** pointer of each autoincrement table to record some side information that
+** the code generator needs.  We have to keep per-table autoincrement
+** information in case inserts are done within triggers.  Triggers do not
+** normally coordinate their activities, but we do need to coordinate the
+** loading and saving of autoincrement information.
+*/
+struct AutoincInfo {
+  AutoincInfo *pNext;   /* Next info block in a list of them all */
+  Table *pTab;          /* Table this info block refers to */
+  int iDb;              /* Index in sqlite3.aDb[] of database holding pTab */
+  int regCtr;           /* Memory register holding the rowid counter */
+};
+
+/*
+** At least one instance of the following structure is created for each
+** trigger that may be fired while parsing an INSERT, UPDATE or DELETE
+** statement. All such objects are stored in the linked list headed at
+** Parse.pTriggerPrg and deleted once statement compilation has been
+** completed.
+**
+** A Vdbe sub-program that implements the body and WHEN clause of trigger
+** TriggerPrg.pTrigger, assuming a default ON CONFLICT clause of
+** TriggerPrg.orconf, is stored in the TriggerPrg.pProgram variable.
+** The Parse.pTriggerPrg list never contains two entries with the same
+** values for both pTrigger and orconf.
+**
+** The TriggerPrg.aColmask[0] variable is set to a mask of old.* columns
+** accessed (or set to 0 for triggers fired as a result of INSERT
+** statements). Similarly, the TriggerPrg.aColmask[1] variable is set to
+** a mask of new.* columns used by the program.
+*/
+struct TriggerPrg {
+  Trigger *pTrigger;      /* Trigger this program was coded from */
+  TriggerPrg *pNext;      /* Next entry in Parse.pTriggerPrg list */
+  SubProgram *pProgram;   /* Program implementing pTrigger/orconf */
+  int orconf;             /* Default ON CONFLICT policy */
+  u32 aColmask[2];        /* Masks of old.*, new.* columns accessed */
+};
+
+/*
+** The yDbMask datatype for the bitmask of all attached databases.
+*/
+#if SQLITE_MAX_ATTACHED>30
+  typedef unsigned char yDbMask[(SQLITE_MAX_ATTACHED+9)/8];
+# define DbMaskTest(M,I)    (((M)[(I)/8]&(1<<((I)&7)))!=0)
+# define DbMaskZero(M)      memset((M),0,sizeof(M))
+# define DbMaskSet(M,I)     (M)[(I)/8]|=(1<<((I)&7))
+# define DbMaskAllZero(M)   sqlite3DbMaskAllZero(M)
+# define DbMaskNonZero(M)   (sqlite3DbMaskAllZero(M)==0)
+#else
+  typedef unsigned int yDbMask;
+# define DbMaskTest(M,I)    (((M)&(((yDbMask)1)<<(I)))!=0)
+# define DbMaskZero(M)      ((M)=0)
+# define DbMaskSet(M,I)     ((M)|=(((yDbMask)1)<<(I)))
+# define DbMaskAllZero(M)   ((M)==0)
+# define DbMaskNonZero(M)   ((M)!=0)
+#endif
+
+/*
+** For each index X that has as one of its arguments either an expression
+** or the name of a virtual generated column, and if X is in scope such that
+** the value of the expression can simply be read from the index, then
+** there is an instance of this object on the Parse.pIdxExpr list.
+**
+** During code generation, while generating code to evaluate expressions,
+** this list is consulted and if a matching expression is found, the value
+** is read from the index rather than being recomputed.
+*/
+struct IndexedExpr {
+  Expr *pExpr;            /* The expression contained in the index */
+  int iDataCur;           /* The data cursor associated with the index */
+  int iIdxCur;            /* The index cursor */
+  int iIdxCol;            /* The index column that contains value of pExpr */
+  u8 bMaybeNullRow;       /* True if we need an OP_IfNullRow check */
+  u8 aff;                 /* Affinity of the pExpr expression */
+  IndexedExpr *pIENext;   /* Next in a list of all indexed expressions */
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  const char *zIdxName;   /* Name of index, used only for bytecode comments */
+#endif
+};
+
+/*
+** An instance of the ParseCleanup object specifies an operation that
+** should be performed after parsing to deallocation resources obtained
+** during the parse and which are no longer needed.
+*/
+struct ParseCleanup {
+  ParseCleanup *pNext;               /* Next cleanup task */
+  void *pPtr;                        /* Pointer to object to deallocate */
+  void (*xCleanup)(sqlite3*,void*);  /* Deallocation routine */
+};
+
+/*
+** An SQL parser context.  A copy of this structure is passed through
+** the parser and down into all the parser action routine in order to
+** carry around information that is global to the entire parse.
+**
+** The structure is divided into two parts.  When the parser and code
+** generate call themselves recursively, the first part of the structure
+** is constant but the second part is reset at the beginning and end of
+** each recursion.
+**
+** The nTableLock and aTableLock variables are only used if the shared-cache
+** feature is enabled (if sqlite3Tsd()->useSharedData is true). They are
+** used to store the set of table-locks required by the statement being
+** compiled. Function sqlite3TableLock() is used to add entries to the
+** list.
+*/
+struct Parse {
+  sqlite3 *db;         /* The main database structure */
+  char *zErrMsg;       /* An error message */
+  Vdbe *pVdbe;         /* An engine for executing database bytecode */
+  int rc;              /* Return code from execution */
+  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
+  u8 checkSchema;      /* Causes schema cookie check after an error */
+  u8 nested;           /* Number of nested calls to the parser/code generator */
+  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
+  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
+  u8 mayAbort;         /* True if statement may throw an ABORT exception */
+  u8 hasCompound;      /* Need to invoke convertCompoundSelectToSubquery() */
+  u8 okConstFactor;    /* OK to factor out constants */
+  u8 disableLookaside; /* Number of times lookaside has been disabled */
+  u8 prepFlags;        /* SQLITE_PREPARE_* flags */
+  u8 withinRJSubrtn;   /* Nesting level for RIGHT JOIN body subroutines */
+  u8 bHasWith;         /* True if statement contains WITH */
+  u8 mSubrtnSig;       /* mini Bloom filter on available SubrtnSig.selId */
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+  u8 earlyCleanup;     /* OOM inside sqlite3ParserAddCleanup() */
+#endif
+#ifdef SQLITE_DEBUG
+  u8 ifNotExists;      /* Might be true if IF NOT EXISTS.  Assert()s only */
+#endif
+  int nRangeReg;       /* Size of the temporary register block */
+  int iRangeReg;       /* First register in temporary register block */
+  int nErr;            /* Number of errors seen */
+  int nTab;            /* Number of previously allocated VDBE cursors */
+  int nMem;            /* Number of memory cells used so far */
+  int szOpAlloc;       /* Bytes of memory space allocated for Vdbe.aOp[] */
+  int iSelfTab;        /* Table associated with an index on expr, or negative
+                       ** of the base register during check-constraint eval */
+  int nLabel;          /* The *negative* of the number of labels used */
+  int nLabelAlloc;     /* Number of slots in aLabel */
+  int *aLabel;         /* Space to hold the labels */
+  ExprList *pConstExpr;/* Constant expressions */
+  IndexedExpr *pIdxEpr;/* List of expressions used by active indexes */
+  IndexedExpr *pIdxPartExpr; /* Exprs constrained by index WHERE clauses */
+  Token constraintName;/* Name of the constraint currently being parsed */
+  yDbMask writeMask;   /* Start a write transaction on these databases */
+  yDbMask cookieMask;  /* Bitmask of schema verified databases */
+  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
+  int regRoot;         /* Register holding root page number for new objects */
+  int nMaxArg;         /* Max args passed to user function by sub-program */
+  int nSelect;         /* Number of SELECT stmts. Counter for Select.selId */
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  u32 nProgressSteps;  /* xProgress steps taken during sqlite3_prepare() */
+#endif
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  int nTableLock;        /* Number of locks in aTableLock */
+  TableLock *aTableLock; /* Required table locks for shared-cache mode */
+#endif
+  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */
+  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
+  Table *pTriggerTab;  /* Table triggers are being coded for */
+  TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
+  ParseCleanup *pCleanup;   /* List of cleanup operations to run after parse */
+  union {
+    int addrCrTab;         /* Address of OP_CreateBtree on CREATE TABLE */
+    Returning *pReturning; /* The RETURNING clause */
+  } u1;
+  u32 oldmask;         /* Mask of old.* columns referenced */
+  u32 newmask;         /* Mask of new.* columns referenced */
+  LogEst nQueryLoop;   /* Est number of iterations of a query (10*log2(N)) */
+  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
+  u8 bReturning;       /* Coding a RETURNING trigger */
+  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
+  u8 disableTriggers;  /* True to disable triggers */
+
+  /**************************************************************************
+  ** Fields above must be initialized to zero.  The fields that follow,
+  ** down to the beginning of the recursive section, do not need to be
+  ** initialized as they will be set before being used.  The boundary is
+  ** determined by offsetof(Parse,aTempReg).
+  **************************************************************************/
+
+  int aTempReg[8];        /* Holding area for temporary registers */
+  Parse *pOuterParse;     /* Outer Parse object when nested */
+  Token sNameToken;       /* Token with unqualified schema object name */
+
+  /************************************************************************
+  ** Above is constant between recursions.  Below is reset before and after
+  ** each recursion.  The boundary between these two regions is determined
+  ** using offsetof(Parse,sLastToken) so the sLastToken field must be the
+  ** first field in the recursive region.
+  ************************************************************************/
+
+  Token sLastToken;       /* The last token parsed */
+  ynVar nVar;               /* Number of '?' variables seen in the SQL so far */
+  u8 iPkSortOrder;          /* ASC or DESC for INTEGER PRIMARY KEY */
+  u8 explain;               /* True if the EXPLAIN flag is found on the query */
+  u8 eParseMode;            /* PARSE_MODE_XXX constant */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  int nVtabLock;            /* Number of virtual tables to lock */
+#endif
+  int nHeight;              /* Expression tree height of current sub-select */
+  int addrExplain;          /* Address of current OP_Explain opcode */
+  VList *pVList;            /* Mapping between variable names and numbers */
+  Vdbe *pReprepare;         /* VM being reprepared (sqlite3Reprepare()) */
+  const char *zTail;        /* All SQL text past the last semicolon parsed */
+  Table *pNewTable;         /* A table being constructed by CREATE TABLE */
+  Index *pNewIndex;         /* An index being constructed by CREATE INDEX.
+                            ** Also used to hold redundant UNIQUE constraints
+                            ** during a RENAME COLUMN */
+  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
+  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  Token sArg;               /* Complete text of a module argument */
+  Table **apVtabLock;       /* Pointer to virtual tables needing locking */
+#endif
+  With *pWith;              /* Current WITH clause, or NULL */
+#ifndef SQLITE_OMIT_ALTERTABLE
+  RenameToken *pRename;     /* Tokens subject to renaming by ALTER TABLE */
+#endif
+};
+
+/* Allowed values for Parse.eParseMode
+*/
+#define PARSE_MODE_NORMAL        0
+#define PARSE_MODE_DECLARE_VTAB  1
+#define PARSE_MODE_RENAME        2
+#define PARSE_MODE_UNMAP         3
+
+/*
+** Sizes and pointers of various parts of the Parse object.
+*/
+#define PARSE_HDR(X)  (((char*)(X))+offsetof(Parse,zErrMsg))
+#define PARSE_HDR_SZ (offsetof(Parse,aTempReg)-offsetof(Parse,zErrMsg)) /* Recursive part w/o aColCache*/
+#define PARSE_RECURSE_SZ offsetof(Parse,sLastToken)    /* Recursive part */
+#define PARSE_TAIL_SZ (sizeof(Parse)-PARSE_RECURSE_SZ) /* Non-recursive part */
+#define PARSE_TAIL(X) (((char*)(X))+PARSE_RECURSE_SZ)  /* Pointer to tail */
+
+/*
+** Return true if currently inside an sqlite3_declare_vtab() call.
+*/
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+  #define IN_DECLARE_VTAB 0
+#else
+  #define IN_DECLARE_VTAB (pParse->eParseMode==PARSE_MODE_DECLARE_VTAB)
+#endif
+
+#if defined(SQLITE_OMIT_ALTERTABLE)
+  #define IN_RENAME_OBJECT 0
+#else
+  #define IN_RENAME_OBJECT (pParse->eParseMode>=PARSE_MODE_RENAME)
+#endif
+
+#if defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_OMIT_ALTERTABLE)
+  #define IN_SPECIAL_PARSE 0
+#else
+  #define IN_SPECIAL_PARSE (pParse->eParseMode!=PARSE_MODE_NORMAL)
+#endif
+
+/*
+** An instance of the following structure can be declared on a stack and used
+** to save the Parse.zAuthContext value so that it can be restored later.
+*/
+struct AuthContext {
+  const char *zAuthContext;   /* Put saved Parse.zAuthContext here */
+  Parse *pParse;              /* The Parse structure */
+};
+
+/*
+** Bitfield flags for P5 value in various opcodes.
+**
+** Value constraints (enforced via assert()):
+**    OPFLAG_LENGTHARG    == SQLITE_FUNC_LENGTH
+**    OPFLAG_TYPEOFARG    == SQLITE_FUNC_TYPEOF
+**    OPFLAG_BULKCSR      == BTREE_BULKLOAD
+**    OPFLAG_SEEKEQ       == BTREE_SEEK_EQ
+**    OPFLAG_FORDELETE    == BTREE_FORDELETE
+**    OPFLAG_SAVEPOSITION == BTREE_SAVEPOSITION
+**    OPFLAG_AUXDELETE    == BTREE_AUXDELETE
+*/
+#define OPFLAG_NCHANGE       0x01    /* OP_Insert: Set to update db->nChange */
+                                     /* Also used in P2 (not P5) of OP_Delete */
+#define OPFLAG_NOCHNG        0x01    /* OP_VColumn nochange for UPDATE */
+#define OPFLAG_EPHEM         0x01    /* OP_Column: Ephemeral output is ok */
+#define OPFLAG_LASTROWID     0x20    /* Set to update db->lastRowid */
+#define OPFLAG_ISUPDATE      0x04    /* This OP_Insert is an sql UPDATE */
+#define OPFLAG_APPEND        0x08    /* This is likely to be an append */
+#define OPFLAG_USESEEKRESULT 0x10    /* Try to avoid a seek in BtreeInsert() */
+#define OPFLAG_ISNOOP        0x40    /* OP_Delete does pre-update-hook only */
+#define OPFLAG_LENGTHARG     0x40    /* OP_Column only used for length() */
+#define OPFLAG_TYPEOFARG     0x80    /* OP_Column only used for typeof() */
+#define OPFLAG_BYTELENARG    0xc0    /* OP_Column only for octet_length() */
+#define OPFLAG_BULKCSR       0x01    /* OP_Open** used to open bulk cursor */
+#define OPFLAG_SEEKEQ        0x02    /* OP_Open** cursor uses EQ seek only */
+#define OPFLAG_FORDELETE     0x08    /* OP_Open should use BTREE_FORDELETE */
+#define OPFLAG_P2ISREG       0x10    /* P2 to OP_Open** is a register number */
+#define OPFLAG_PERMUTE       0x01    /* OP_Compare: use the permutation */
+#define OPFLAG_SAVEPOSITION  0x02    /* OP_Delete/Insert: save cursor pos */
+#define OPFLAG_AUXDELETE     0x04    /* OP_Delete: index in a DELETE op */
+#define OPFLAG_NOCHNG_MAGIC  0x6d    /* OP_MakeRecord: serialtype 10 is ok */
+#define OPFLAG_PREFORMAT     0x80    /* OP_Insert uses preformatted cell */
+
+/*
+** Each trigger present in the database schema is stored as an instance of
+** struct Trigger.
+**
+** Pointers to instances of struct Trigger are stored in two ways.
+** 1. In the "trigHash" hash table (part of the sqlite3* that represents the
+**    database). This allows Trigger structures to be retrieved by name.
+** 2. All triggers associated with a single table form a linked list, using the
+**    pNext member of struct Trigger. A pointer to the first element of the
+**    linked list is stored as the "pTrigger" member of the associated
+**    struct Table.
+**
+** The "step_list" member points to the first element of a linked list
+** containing the SQL statements specified as the trigger program.
+*/
+struct Trigger {
+  char *zName;            /* The name of the trigger                        */
+  char *table;            /* The table or view to which the trigger applies */
+  u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
+  u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
+  u8 bReturning;          /* This trigger implements a RETURNING clause */
+  Expr *pWhen;            /* The WHEN clause of the expression (may be NULL) */
+  IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
+                             the <column-list> is stored here */
+  Schema *pSchema;        /* Schema containing the trigger */
+  Schema *pTabSchema;     /* Schema containing the table */
+  TriggerStep *step_list; /* Link list of trigger program steps             */
+  Trigger *pNext;         /* Next trigger associated with the table */
+};
+
+/*
+** A trigger is either a BEFORE or an AFTER trigger.  The following constants
+** determine which.
+**
+** If there are multiple triggers, you might of some BEFORE and some AFTER.
+** In that cases, the constants below can be ORed together.
+*/
+#define TRIGGER_BEFORE  1
+#define TRIGGER_AFTER   2
+
+/*
+** An instance of struct TriggerStep is used to store a single SQL statement
+** that is a part of a trigger-program.
+**
+** Instances of struct TriggerStep are stored in a singly linked list (linked
+** using the "pNext" member) referenced by the "step_list" member of the
+** associated struct Trigger instance. The first element of the linked list is
+** the first step of the trigger-program.
+**
+** The "op" member indicates whether this is a "DELETE", "INSERT", "UPDATE" or
+** "SELECT" statement. The meanings of the other members is determined by the
+** value of "op" as follows:
+**
+** (op == TK_INSERT)
+** orconf    -> stores the ON CONFLICT algorithm
+** pSelect   -> The content to be inserted - either a SELECT statement or
+**              a VALUES clause.
+** zTarget   -> Dequoted name of the table to insert into.
+** pIdList   -> If this is an INSERT INTO ... (<column-names>) VALUES ...
+**              statement, then this stores the column-names to be
+**              inserted into.
+** pUpsert   -> The ON CONFLICT clauses for an Upsert
+**
+** (op == TK_DELETE)
+** zTarget   -> Dequoted name of the table to delete from.
+** pWhere    -> The WHERE clause of the DELETE statement if one is specified.
+**              Otherwise NULL.
+**
+** (op == TK_UPDATE)
+** zTarget   -> Dequoted name of the table to update.
+** pWhere    -> The WHERE clause of the UPDATE statement if one is specified.
+**              Otherwise NULL.
+** pExprList -> A list of the columns to update and the expressions to update
+**              them to. See sqlite3Update() documentation of "pChanges"
+**              argument.
+**
+** (op == TK_SELECT)
+** pSelect   -> The SELECT statement
+**
+** (op == TK_RETURNING)
+** pExprList -> The list of expressions that follow the RETURNING keyword.
+**
+*/
+struct TriggerStep {
+  u8 op;               /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT,
+                       ** or TK_RETURNING */
+  u8 orconf;           /* OE_Rollback etc. */
+  Trigger *pTrig;      /* The trigger that this step is a part of */
+  Select *pSelect;     /* SELECT statement or RHS of INSERT INTO SELECT ... */
+  char *zTarget;       /* Target table for DELETE, UPDATE, INSERT */
+  SrcList *pFrom;      /* FROM clause for UPDATE statement (if any) */
+  Expr *pWhere;        /* The WHERE clause for DELETE or UPDATE steps */
+  ExprList *pExprList; /* SET clause for UPDATE, or RETURNING clause */
+  IdList *pIdList;     /* Column names for INSERT */
+  Upsert *pUpsert;     /* Upsert clauses on an INSERT */
+  char *zSpan;         /* Original SQL text of this command */
+  TriggerStep *pNext;  /* Next in the link-list */
+  TriggerStep *pLast;  /* Last element in link-list. Valid for 1st elem only */
+};
+
+/*
+** Information about a RETURNING clause
+*/
+struct Returning {
+  Parse *pParse;        /* The parse that includes the RETURNING clause */
+  ExprList *pReturnEL;  /* List of expressions to return */
+  Trigger retTrig;      /* The transient trigger that implements RETURNING */
+  TriggerStep retTStep; /* The trigger step */
+  int iRetCur;          /* Transient table holding RETURNING results */
+  int nRetCol;          /* Number of in pReturnEL after expansion */
+  int iRetReg;          /* Register array for holding a row of RETURNING */
+  char zName[40];       /* Name of trigger: "sqlite_returning_%p" */
+};
+
+/*
+** An object used to accumulate the text of a string where we
+** do not necessarily know how big the string will be in the end.
+*/
+struct sqlite3_str {
+  sqlite3 *db;         /* Optional database for lookaside.  Can be NULL */
+  char *zText;         /* The string collected so far */
+  u32  nAlloc;         /* Amount of space allocated in zText */
+  u32  mxAlloc;        /* Maximum allowed allocation.  0 for no malloc usage */
+  u32  nChar;          /* Length of the string so far */
+  u8   accError;       /* SQLITE_NOMEM or SQLITE_TOOBIG */
+  u8   printfFlags;    /* SQLITE_PRINTF flags below */
+};
+#define SQLITE_PRINTF_INTERNAL 0x01  /* Internal-use-only converters allowed */
+#define SQLITE_PRINTF_SQLFUNC  0x02  /* SQL function arguments to VXPrintf */
+#define SQLITE_PRINTF_MALLOCED 0x04  /* True if zText is allocated space */
+
+#define isMalloced(X)  (((X)->printfFlags & SQLITE_PRINTF_MALLOCED)!=0)
+
+/*
+** The following object is the header for an "RCStr" or "reference-counted
+** string".  An RCStr is passed around and used like any other char*
+** that has been dynamically allocated.  The important interface
+** differences:
+**
+**   1.  RCStr strings are reference counted.  They are deallocated
+**       when the reference count reaches zero.
+**
+**   2.  Use sqlite3RCStrUnref() to free an RCStr string rather than
+**       sqlite3_free()
+**
+**   3.  Make a (read-only) copy of a read-only RCStr string using
+**       sqlite3RCStrRef().
+**
+** "String" is in the name, but an RCStr object can also be used to hold
+** binary data.
+*/
+struct RCStr {
+  u64 nRCRef;            /* Number of references */
+  /* Total structure size should be a multiple of 8 bytes for alignment */
+};
+
+/*
+** A pointer to this structure is used to communicate information
+** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
+*/
+typedef struct {
+  sqlite3 *db;        /* The database being initialized */
+  char **pzErrMsg;    /* Error message stored here */
+  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
+  int rc;             /* Result code stored here */
+  u32 mInitFlags;     /* Flags controlling error messages */
+  u32 nInitRow;       /* Number of rows processed */
+  Pgno mxPage;        /* Maximum page number.  0 for no limit. */
+} InitData;
+
+/*
+** Allowed values for mInitFlags
+*/
+#define INITFLAG_AlterMask     0x0003  /* Types of ALTER */
+#define INITFLAG_AlterRename   0x0001  /* Reparse after a RENAME */
+#define INITFLAG_AlterDrop     0x0002  /* Reparse after a DROP COLUMN */
+#define INITFLAG_AlterAdd      0x0003  /* Reparse after an ADD COLUMN */
+
+/* Tuning parameters are set using SQLITE_TESTCTRL_TUNE and are controlled
+** on debug-builds of the CLI using ".testctrl tune ID VALUE".  Tuning
+** parameters are for temporary use during development, to help find
+** optimal values for parameters in the query planner.  The should not
+** be used on trunk check-ins.  They are a temporary mechanism available
+** for transient development builds only.
+**
+** Tuning parameters are numbered starting with 1.
+*/
+#define SQLITE_NTUNE  6             /* Should be zero for all trunk check-ins */
+#ifdef SQLITE_DEBUG
+# define Tuning(X)  (sqlite3Config.aTune[(X)-1])
+#else
+# define Tuning(X)  0
+#endif
+
+/*
+** Structure containing global configuration data for the SQLite library.
+**
+** This structure also contains some state information.
+*/
+struct Sqlite3Config {
+  int bMemstat;                     /* True to enable memory status */
+  u8 bCoreMutex;                    /* True to enable core mutexing */
+  u8 bFullMutex;                    /* True to enable full mutexing */
+  u8 bOpenUri;                      /* True to interpret filenames as URIs */
+  u8 bUseCis;                       /* Use covering indices for full-scans */
+  u8 bSmallMalloc;                  /* Avoid large memory allocations if true */
+  u8 bExtraSchemaChecks;            /* Verify type,name,tbl_name in schema */
+#ifdef SQLITE_DEBUG
+  u8 bJsonSelfcheck;                /* Double-check JSON parsing */
+#endif
+  int mxStrlen;                     /* Maximum string length */
+  int neverCorrupt;                 /* Database is always well-formed */
+  int szLookaside;                  /* Default lookaside buffer size */
+  int nLookaside;                   /* Default lookaside buffer count */
+  int nStmtSpill;                   /* Stmt-journal spill-to-disk threshold */
+  sqlite3_mem_methods m;            /* Low-level memory allocation interface */
+  sqlite3_mutex_methods mutex;      /* Low-level mutex interface */
+  sqlite3_pcache_methods2 pcache2;  /* Low-level page-cache interface */
+  void *pHeap;                      /* Heap storage space */
+  int nHeap;                        /* Size of pHeap[] */
+  int mnReq, mxReq;                 /* Min and max heap requests sizes */
+  sqlite3_int64 szMmap;             /* mmap() space per open file */
+  sqlite3_int64 mxMmap;             /* Maximum value for szMmap */
+  void *pPage;                      /* Page cache memory */
+  int szPage;                       /* Size of each page in pPage[] */
+  int nPage;                        /* Number of pages in pPage[] */
+  int mxParserStack;                /* maximum depth of the parser stack */
+  int sharedCacheEnabled;           /* true if shared-cache mode enabled */
+  u32 szPma;                        /* Maximum Sorter PMA size */
+  /* The above might be initialized to non-zero.  The following need to always
+  ** initially be zero, however. */
+  int isInit;                       /* True after initialization has finished */
+  int inProgress;                   /* True while initialization in progress */
+  int isMutexInit;                  /* True after mutexes are initialized */
+  int isMallocInit;                 /* True after malloc is initialized */
+  int isPCacheInit;                 /* True after malloc is initialized */
+  int nRefInitMutex;                /* Number of users of pInitMutex */
+  sqlite3_mutex *pInitMutex;        /* Mutex used by sqlite3_initialize() */
+  void (*xLog)(void*,int,const char*); /* Function for logging */
+  void *pLogArg;                       /* First argument to xLog() */
+#ifdef SQLITE_ENABLE_SQLLOG
+  void(*xSqllog)(void*,sqlite3*,const char*, int);
+  void *pSqllogArg;
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  /* The following callback (if not NULL) is invoked on every VDBE branch
+  ** operation.  Set the callback using SQLITE_TESTCTRL_VDBE_COVERAGE.
+  */
+  void (*xVdbeBranch)(void*,unsigned iSrcLine,u8 eThis,u8 eMx);  /* Callback */
+  void *pVdbeBranchArg;                                     /* 1st argument */
+#endif
+#ifndef SQLITE_OMIT_DESERIALIZE
+  sqlite3_int64 mxMemdbSize;        /* Default max memdb size */
+#endif
+#ifndef SQLITE_UNTESTABLE
+  int (*xTestCallback)(int);        /* Invoked by sqlite3FaultSim() */
+#endif
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  u32 mNoVisibleRowid;              /* TF_NoVisibleRowid if the ROWID_IN_VIEW
+                                    ** feature is disabled.  0 if rowids can
+                                    ** occur in views. */
+#endif
+  int bLocaltimeFault;              /* True to fail localtime() calls */
+  int (*xAltLocaltime)(const void*,void*); /* Alternative localtime() routine */
+  int iOnceResetThreshold;          /* When to reset OP_Once counters */
+  u32 szSorterRef;                  /* Min size in bytes to use sorter-refs */
+  unsigned int iPrngSeed;           /* Alternative fixed seed for the PRNG */
+  /* vvvv--- must be last ---vvv */
+#ifdef SQLITE_DEBUG
+  sqlite3_int64 aTune[SQLITE_NTUNE]; /* Tuning parameters */
+#endif
+};
+
+/*
+** This macro is used inside of assert() statements to indicate that
+** the assert is only valid on a well-formed database.  Instead of:
+**
+**     assert( X );
+**
+** One writes:
+**
+**     assert( X || CORRUPT_DB );
+**
+** CORRUPT_DB is true during normal operation.  CORRUPT_DB does not indicate
+** that the database is definitely corrupt, only that it might be corrupt.
+** For most test cases, CORRUPT_DB is set to false using a special
+** sqlite3_test_control().  This enables assert() statements to prove
+** things that are always true for well-formed databases.
+*/
+#define CORRUPT_DB  (sqlite3Config.neverCorrupt==0)
+
+/*
+** Context pointer passed down through the tree-walk.
+*/
+struct Walker {
+  Parse *pParse;                            /* Parser context.  */
+  int (*xExprCallback)(Walker*, Expr*);     /* Callback for expressions */
+  int (*xSelectCallback)(Walker*,Select*);  /* Callback for SELECTs */
+  void (*xSelectCallback2)(Walker*,Select*);/* Second callback for SELECTs */
+  int walkerDepth;                          /* Number of subqueries */
+  u16 eCode;                                /* A small processing code */
+  u16 mWFlags;                              /* Use-dependent flags */
+  union {                                   /* Extra data for callback */
+    NameContext *pNC;                         /* Naming context */
+    int n;                                    /* A counter */
+    int iCur;                                 /* A cursor number */
+    SrcList *pSrcList;                        /* FROM clause */
+    struct CCurHint *pCCurHint;               /* Used by codeCursorHint() */
+    struct RefSrcList *pRefSrcList;           /* sqlite3ReferencesSrcList() */
+    int *aiCol;                               /* array of column indexes */
+    struct IdxCover *pIdxCover;               /* Check for index coverage */
+    ExprList *pGroupBy;                       /* GROUP BY clause */
+    Select *pSelect;                          /* HAVING to WHERE clause ctx */
+    struct WindowRewrite *pRewrite;           /* Window rewrite context */
+    struct WhereConst *pConst;                /* WHERE clause constants */
+    struct RenameCtx *pRename;                /* RENAME COLUMN context */
+    struct Table *pTab;                       /* Table of generated column */
+    struct CoveringIndexCheck *pCovIdxCk;     /* Check for covering index */
+    SrcItem *pSrcItem;                        /* A single FROM clause item */
+    DbFixer *pFix;                            /* See sqlite3FixSelect() */
+    Mem *aMem;                                /* See sqlite3BtreeCursorHint() */
+  } u;
+};
+
+/*
+** The following structure contains information used by the sqliteFix...
+** routines as they walk the parse tree to make database references
+** explicit.
+*/
+struct DbFixer {
+  Parse *pParse;      /* The parsing context.  Error messages written here */
+  Walker w;           /* Walker object */
+  Schema *pSchema;    /* Fix items to this schema */
+  u8 bTemp;           /* True for TEMP schema entries */
+  const char *zDb;    /* Make sure all objects are contained in this database */
+  const char *zType;  /* Type of the container - used for error messages */
+  const Token *pName; /* Name of the container - used for error messages */
+};
+
+/* Forward declarations */
+SQLITE_PRIVATE int sqlite3WalkExpr(Walker*, Expr*);
+SQLITE_PRIVATE int sqlite3WalkExprNN(Walker*, Expr*);
+SQLITE_PRIVATE int sqlite3WalkExprList(Walker*, ExprList*);
+SQLITE_PRIVATE int sqlite3WalkSelect(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3WalkSelectExpr(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3WalkSelectFrom(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3ExprWalkNoop(Walker*, Expr*);
+SQLITE_PRIVATE int sqlite3SelectWalkNoop(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3SelectWalkFail(Walker*, Select*);
+SQLITE_PRIVATE int sqlite3WalkerDepthIncrease(Walker*,Select*);
+SQLITE_PRIVATE void sqlite3WalkerDepthDecrease(Walker*,Select*);
+SQLITE_PRIVATE void sqlite3WalkWinDefnDummyCallback(Walker*,Select*);
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE void sqlite3SelectWalkAssert2(Walker*, Select*);
+#endif
+
+#ifndef SQLITE_OMIT_CTE
+SQLITE_PRIVATE void sqlite3SelectPopWith(Walker*, Select*);
+#else
+# define sqlite3SelectPopWith 0
+#endif
+
+/*
+** Return code from the parse-tree walking primitives and their
+** callbacks.
+*/
+#define WRC_Continue    0   /* Continue down into children */
+#define WRC_Prune       1   /* Omit children but continue walking siblings */
+#define WRC_Abort       2   /* Abandon the tree walk */
+
+/*
+** A single common table expression
+*/
+struct Cte {
+  char *zName;            /* Name of this CTE */
+  ExprList *pCols;        /* List of explicit column names, or NULL */
+  Select *pSelect;        /* The definition of this CTE */
+  const char *zCteErr;    /* Error message for circular references */
+  CteUse *pUse;           /* Usage information for this CTE */
+  u8 eM10d;               /* The MATERIALIZED flag */
+};
+
+/*
+** Allowed values for the materialized flag (eM10d):
+*/
+#define M10d_Yes       0  /* AS MATERIALIZED */
+#define M10d_Any       1  /* Not specified.  Query planner's choice */
+#define M10d_No        2  /* AS NOT MATERIALIZED */
+
+/*
+** An instance of the With object represents a WITH clause containing
+** one or more CTEs (common table expressions).
+*/
+struct With {
+  int nCte;               /* Number of CTEs in the WITH clause */
+  int bView;              /* Belongs to the outermost Select of a view */
+  With *pOuter;           /* Containing WITH clause, or NULL */
+  Cte a[1];               /* For each CTE in the WITH clause.... */
+};
+
+/*
+** The Cte object is not guaranteed to persist for the entire duration
+** of code generation.  (The query flattener or other parser tree
+** edits might delete it.)  The following object records information
+** about each Common Table Expression that must be preserved for the
+** duration of the parse.
+**
+** The CteUse objects are freed using sqlite3ParserAddCleanup() rather
+** than sqlite3SelectDelete(), which is what enables them to persist
+** until the end of code generation.
+*/
+struct CteUse {
+  int nUse;              /* Number of users of this CTE */
+  int addrM9e;           /* Start of subroutine to compute materialization */
+  int regRtn;            /* Return address register for addrM9e subroutine */
+  int iCur;              /* Ephemeral table holding the materialization */
+  LogEst nRowEst;        /* Estimated number of rows in the table */
+  u8 eM10d;              /* The MATERIALIZED flag */
+};
+
+
+/* Client data associated with sqlite3_set_clientdata() and
+** sqlite3_get_clientdata().
+*/
+struct DbClientData {
+  DbClientData *pNext;        /* Next in a linked list */
+  void *pData;                /* The data */
+  void (*xDestructor)(void*); /* Destructor.  Might be NULL */
+  char zName[1];              /* Name of this client data. MUST BE LAST */
+};
+
+#ifdef SQLITE_DEBUG
+/*
+** An instance of the TreeView object is used for printing the content of
+** data structures on sqlite3DebugPrintf() using a tree-like view.
+*/
+struct TreeView {
+  int iLevel;             /* Which level of the tree we are on */
+  u8  bLine[100];         /* Draw vertical in column i if bLine[i] is true */
+};
+#endif /* SQLITE_DEBUG */
+
+/*
+** This object is used in various ways, most (but not all) related to window
+** functions.
+**
+**   (1) A single instance of this structure is attached to the
+**       the Expr.y.pWin field for each window function in an expression tree.
+**       This object holds the information contained in the OVER clause,
+**       plus additional fields used during code generation.
+**
+**   (2) All window functions in a single SELECT form a linked-list
+**       attached to Select.pWin.  The Window.pFunc and Window.pExpr
+**       fields point back to the expression that is the window function.
+**
+**   (3) The terms of the WINDOW clause of a SELECT are instances of this
+**       object on a linked list attached to Select.pWinDefn.
+**
+**   (4) For an aggregate function with a FILTER clause, an instance
+**       of this object is stored in Expr.y.pWin with eFrmType set to
+**       TK_FILTER. In this case the only field used is Window.pFilter.
+**
+** The uses (1) and (2) are really the same Window object that just happens
+** to be accessible in two different ways.  Use case (3) are separate objects.
+*/
+struct Window {
+  char *zName;            /* Name of window (may be NULL) */
+  char *zBase;            /* Name of base window for chaining (may be NULL) */
+  ExprList *pPartition;   /* PARTITION BY clause */
+  ExprList *pOrderBy;     /* ORDER BY clause */
+  u8 eFrmType;            /* TK_RANGE, TK_GROUPS, TK_ROWS, or 0 */
+  u8 eStart;              /* UNBOUNDED, CURRENT, PRECEDING or FOLLOWING */
+  u8 eEnd;                /* UNBOUNDED, CURRENT, PRECEDING or FOLLOWING */
+  u8 bImplicitFrame;      /* True if frame was implicitly specified */
+  u8 eExclude;            /* TK_NO, TK_CURRENT, TK_TIES, TK_GROUP, or 0 */
+  Expr *pStart;           /* Expression for "<expr> PRECEDING" */
+  Expr *pEnd;             /* Expression for "<expr> FOLLOWING" */
+  Window **ppThis;        /* Pointer to this object in Select.pWin list */
+  Window *pNextWin;       /* Next window function belonging to this SELECT */
+  Expr *pFilter;          /* The FILTER expression */
+  FuncDef *pWFunc;        /* The function */
+  int iEphCsr;            /* Partition buffer or Peer buffer */
+  int regAccum;           /* Accumulator */
+  int regResult;          /* Interim result */
+  int csrApp;             /* Function cursor (used by min/max) */
+  int regApp;             /* Function register (also used by min/max) */
+  int regPart;            /* Array of registers for PARTITION BY values */
+  Expr *pOwner;           /* Expression object this window is attached to */
+  int nBufferCol;         /* Number of columns in buffer table */
+  int iArgCol;            /* Offset of first argument for this function */
+  int regOne;             /* Register containing constant value 1 */
+  int regStartRowid;
+  int regEndRowid;
+  u8 bExprArgs;           /* Defer evaluation of window function arguments
+                          ** due to the SQLITE_SUBTYPE flag */
+};
+
+SQLITE_PRIVATE Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow);
+SQLITE_PRIVATE void sqlite3MultiValuesEnd(Parse *pParse, Select *pVal);
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE void sqlite3WindowDelete(sqlite3*, Window*);
+SQLITE_PRIVATE void sqlite3WindowUnlinkFromSelect(Window*);
+SQLITE_PRIVATE void sqlite3WindowListDelete(sqlite3 *db, Window *p);
+SQLITE_PRIVATE Window *sqlite3WindowAlloc(Parse*, int, int, Expr*, int , Expr*, u8);
+SQLITE_PRIVATE void sqlite3WindowAttach(Parse*, Expr*, Window*);
+SQLITE_PRIVATE void sqlite3WindowLink(Select *pSel, Window *pWin);
+SQLITE_PRIVATE int sqlite3WindowCompare(const Parse*, const Window*, const Window*, int);
+SQLITE_PRIVATE void sqlite3WindowCodeInit(Parse*, Select*);
+SQLITE_PRIVATE void sqlite3WindowCodeStep(Parse*, Select*, WhereInfo*, int, int);
+SQLITE_PRIVATE int sqlite3WindowRewrite(Parse*, Select*);
+SQLITE_PRIVATE void sqlite3WindowUpdate(Parse*, Window*, Window*, FuncDef*);
+SQLITE_PRIVATE Window *sqlite3WindowDup(sqlite3 *db, Expr *pOwner, Window *p);
+SQLITE_PRIVATE Window *sqlite3WindowListDup(sqlite3 *db, Window *p);
+SQLITE_PRIVATE void sqlite3WindowFunctions(void);
+SQLITE_PRIVATE void sqlite3WindowChain(Parse*, Window*, Window*);
+SQLITE_PRIVATE Window *sqlite3WindowAssemble(Parse*, Window*, ExprList*, ExprList*, Token*);
+#else
+# define sqlite3WindowDelete(a,b)
+# define sqlite3WindowFunctions()
+# define sqlite3WindowAttach(a,b,c)
+#endif
+
+/*
+** Assuming zIn points to the first byte of a UTF-8 character,
+** advance zIn to point to the first byte of the next UTF-8 character.
+*/
+#define SQLITE_SKIP_UTF8(zIn) {                        \
+  if( (*(zIn++))>=0xc0 ){                              \
+    while( (*zIn & 0xc0)==0x80 ){ zIn++; }             \
+  }                                                    \
+}
+
+/*
+** The SQLITE_*_BKPT macros are substitutes for the error codes with
+** the same name but without the _BKPT suffix.  These macros invoke
+** routines that report the line-number on which the error originated
+** using sqlite3_log().  The routines also provide a convenient place
+** to set a debugger breakpoint.
+*/
+SQLITE_PRIVATE int sqlite3ReportError(int iErr, int lineno, const char *zType);
+SQLITE_PRIVATE int sqlite3CorruptError(int);
+SQLITE_PRIVATE int sqlite3MisuseError(int);
+SQLITE_PRIVATE int sqlite3CantopenError(int);
+#define SQLITE_CORRUPT_BKPT sqlite3CorruptError(__LINE__)
+#define SQLITE_MISUSE_BKPT sqlite3MisuseError(__LINE__)
+#define SQLITE_CANTOPEN_BKPT sqlite3CantopenError(__LINE__)
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   int sqlite3NomemError(int);
+SQLITE_PRIVATE   int sqlite3IoerrnomemError(int);
+# define SQLITE_NOMEM_BKPT sqlite3NomemError(__LINE__)
+# define SQLITE_IOERR_NOMEM_BKPT sqlite3IoerrnomemError(__LINE__)
+#else
+# define SQLITE_NOMEM_BKPT SQLITE_NOMEM
+# define SQLITE_IOERR_NOMEM_BKPT SQLITE_IOERR_NOMEM
+#endif
+#if defined(SQLITE_DEBUG) || defined(SQLITE_ENABLE_CORRUPT_PGNO)
+SQLITE_PRIVATE   int sqlite3CorruptPgnoError(int,Pgno);
+# define SQLITE_CORRUPT_PGNO(P) sqlite3CorruptPgnoError(__LINE__,(P))
+#else
+# define SQLITE_CORRUPT_PGNO(P) sqlite3CorruptError(__LINE__)
+#endif
+
+/*
+** FTS3 and FTS4 both require virtual table support
+*/
+#if defined(SQLITE_OMIT_VIRTUALTABLE)
+# undef SQLITE_ENABLE_FTS3
+# undef SQLITE_ENABLE_FTS4
+#endif
+
+/*
+** FTS4 is really an extension for FTS3.  It is enabled using the
+** SQLITE_ENABLE_FTS3 macro.  But to avoid confusion we also call
+** the SQLITE_ENABLE_FTS4 macro to serve as an alias for SQLITE_ENABLE_FTS3.
+*/
+#if defined(SQLITE_ENABLE_FTS4) && !defined(SQLITE_ENABLE_FTS3)
+# define SQLITE_ENABLE_FTS3 1
+#endif
+
+/*
+** The following macros mimic the standard library functions toupper(),
+** isspace(), isalnum(), isdigit() and isxdigit(), respectively. The
+** sqlite versions only work for ASCII characters, regardless of locale.
+*/
+#ifdef SQLITE_ASCII
+# define sqlite3Toupper(x)  ((x)&~(sqlite3CtypeMap[(unsigned char)(x)]&0x20))
+# define sqlite3Isspace(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x01)
+# define sqlite3Isalnum(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x06)
+# define sqlite3Isalpha(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x02)
+# define sqlite3Isdigit(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x04)
+# define sqlite3Isxdigit(x)  (sqlite3CtypeMap[(unsigned char)(x)]&0x08)
+# define sqlite3Tolower(x)   (sqlite3UpperToLower[(unsigned char)(x)])
+# define sqlite3Isquote(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x80)
+# define sqlite3JsonId1(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x42)
+# define sqlite3JsonId2(x)   (sqlite3CtypeMap[(unsigned char)(x)]&0x46)
+#else
+# define sqlite3Toupper(x)   toupper((unsigned char)(x))
+# define sqlite3Isspace(x)   isspace((unsigned char)(x))
+# define sqlite3Isalnum(x)   isalnum((unsigned char)(x))
+# define sqlite3Isalpha(x)   isalpha((unsigned char)(x))
+# define sqlite3Isdigit(x)   isdigit((unsigned char)(x))
+# define sqlite3Isxdigit(x)  isxdigit((unsigned char)(x))
+# define sqlite3Tolower(x)   tolower((unsigned char)(x))
+# define sqlite3Isquote(x)   ((x)=='"'||(x)=='\''||(x)=='['||(x)=='`')
+# define sqlite3JsonId1(x)   (sqlite3IsIdChar(x)&&(x)<'0')
+# define sqlite3JsonId2(x)   sqlite3IsIdChar(x)
+#endif
+SQLITE_PRIVATE int sqlite3IsIdChar(u8);
+
+/*
+** Internal function prototypes
+*/
+SQLITE_PRIVATE int sqlite3StrICmp(const char*,const char*);
+SQLITE_PRIVATE int sqlite3Strlen30(const char*);
+#define sqlite3Strlen30NN(C) (strlen(C)&0x3fffffff)
+SQLITE_PRIVATE char *sqlite3ColumnType(Column*,char*);
+#define sqlite3StrNICmp sqlite3_strnicmp
+
+SQLITE_PRIVATE int sqlite3MallocInit(void);
+SQLITE_PRIVATE void sqlite3MallocEnd(void);
+SQLITE_PRIVATE void *sqlite3Malloc(u64);
+SQLITE_PRIVATE void *sqlite3MallocZero(u64);
+SQLITE_PRIVATE void *sqlite3DbMallocZero(sqlite3*, u64);
+SQLITE_PRIVATE void *sqlite3DbMallocRaw(sqlite3*, u64);
+SQLITE_PRIVATE void *sqlite3DbMallocRawNN(sqlite3*, u64);
+SQLITE_PRIVATE char *sqlite3DbStrDup(sqlite3*,const char*);
+SQLITE_PRIVATE char *sqlite3DbStrNDup(sqlite3*,const char*, u64);
+SQLITE_PRIVATE char *sqlite3DbSpanDup(sqlite3*,const char*,const char*);
+SQLITE_PRIVATE void *sqlite3Realloc(void*, u64);
+SQLITE_PRIVATE void *sqlite3DbReallocOrFree(sqlite3 *, void *, u64);
+SQLITE_PRIVATE void *sqlite3DbRealloc(sqlite3 *, void *, u64);
+SQLITE_PRIVATE void sqlite3DbFree(sqlite3*, void*);
+SQLITE_PRIVATE void sqlite3DbFreeNN(sqlite3*, void*);
+SQLITE_PRIVATE void sqlite3DbNNFreeNN(sqlite3*, void*);
+SQLITE_PRIVATE int sqlite3MallocSize(const void*);
+SQLITE_PRIVATE int sqlite3DbMallocSize(sqlite3*, const void*);
+SQLITE_PRIVATE void *sqlite3PageMalloc(int);
+SQLITE_PRIVATE void sqlite3PageFree(void*);
+SQLITE_PRIVATE void sqlite3MemSetDefault(void);
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE void sqlite3BenignMallocHooks(void (*)(void), void (*)(void));
+#endif
+SQLITE_PRIVATE int sqlite3HeapNearlyFull(void);
+
+/*
+** On systems with ample stack space and that support alloca(), make
+** use of alloca() to obtain space for large automatic objects.  By default,
+** obtain space from malloc().
+**
+** The alloca() routine never returns NULL.  This will cause code paths
+** that deal with sqlite3StackAlloc() failures to be unreachable.
+*/
+#ifdef SQLITE_USE_ALLOCA
+# define sqlite3StackAllocRaw(D,N)   alloca(N)
+# define sqlite3StackAllocRawNN(D,N) alloca(N)
+# define sqlite3StackFree(D,P)
+# define sqlite3StackFreeNN(D,P)
+#else
+# define sqlite3StackAllocRaw(D,N)   sqlite3DbMallocRaw(D,N)
+# define sqlite3StackAllocRawNN(D,N) sqlite3DbMallocRawNN(D,N)
+# define sqlite3StackFree(D,P)       sqlite3DbFree(D,P)
+# define sqlite3StackFreeNN(D,P)     sqlite3DbFreeNN(D,P)
+#endif
+
+/* Do not allow both MEMSYS5 and MEMSYS3 to be defined together.  If they
+** are, disable MEMSYS3
+*/
+#ifdef SQLITE_ENABLE_MEMSYS5
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys5(void);
+#undef SQLITE_ENABLE_MEMSYS3
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS3
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys3(void);
+#endif
+
+
+#ifndef SQLITE_MUTEX_OMIT
+SQLITE_PRIVATE   sqlite3_mutex_methods const *sqlite3DefaultMutex(void);
+SQLITE_PRIVATE   sqlite3_mutex_methods const *sqlite3NoopMutex(void);
+SQLITE_PRIVATE   sqlite3_mutex *sqlite3MutexAlloc(int);
+SQLITE_PRIVATE   int sqlite3MutexInit(void);
+SQLITE_PRIVATE   int sqlite3MutexEnd(void);
+#endif
+#if !defined(SQLITE_MUTEX_OMIT) && !defined(SQLITE_MUTEX_NOOP)
+SQLITE_PRIVATE   void sqlite3MemoryBarrier(void);
+#else
+# define sqlite3MemoryBarrier()
+#endif
+
+SQLITE_PRIVATE sqlite3_int64 sqlite3StatusValue(int);
+SQLITE_PRIVATE void sqlite3StatusUp(int, int);
+SQLITE_PRIVATE void sqlite3StatusDown(int, int);
+SQLITE_PRIVATE void sqlite3StatusHighwater(int, int);
+SQLITE_PRIVATE int sqlite3LookasideUsed(sqlite3*,int*);
+
+/* Access to mutexes used by sqlite3_status() */
+SQLITE_PRIVATE sqlite3_mutex *sqlite3Pcache1Mutex(void);
+SQLITE_PRIVATE sqlite3_mutex *sqlite3MallocMutex(void);
+
+#if defined(SQLITE_ENABLE_MULTITHREADED_CHECKS) && !defined(SQLITE_MUTEX_OMIT)
+SQLITE_PRIVATE void sqlite3MutexWarnOnContention(sqlite3_mutex*);
+#else
+# define sqlite3MutexWarnOnContention(x)
+#endif
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+# define EXP754 (((u64)0x7ff)<<52)
+# define MAN754 ((((u64)1)<<52)-1)
+# define IsNaN(X) (((X)&EXP754)==EXP754 && ((X)&MAN754)!=0)
+# define IsOvfl(X) (((X)&EXP754)==EXP754)
+SQLITE_PRIVATE   int sqlite3IsNaN(double);
+SQLITE_PRIVATE   int sqlite3IsOverflow(double);
+#else
+# define IsNaN(X)             0
+# define sqlite3IsNaN(X)      0
+# define sqlite3IsOVerflow(X) 0
+#endif
+
+/*
+** An instance of the following structure holds information about SQL
+** functions arguments that are the parameters to the printf() function.
+*/
+struct PrintfArguments {
+  int nArg;                /* Total number of arguments */
+  int nUsed;               /* Number of arguments used so far */
+  sqlite3_value **apArg;   /* The argument values */
+};
+
+/*
+** An instance of this object receives the decoding of a floating point
+** value into an approximate decimal representation.
+*/
+struct FpDecode {
+  char sign;           /* '+' or '-' */
+  char isSpecial;      /* 1: Infinity  2: NaN */
+  int n;               /* Significant digits in the decode */
+  int iDP;             /* Location of the decimal point */
+  char *z;             /* Start of significant digits */
+  char zBuf[24];       /* Storage for significant digits */
+};
+
+SQLITE_PRIVATE void sqlite3FpDecode(FpDecode*,double,int,int);
+SQLITE_PRIVATE char *sqlite3MPrintf(sqlite3*,const char*, ...);
+SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3*,const char*, va_list);
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+SQLITE_PRIVATE   void sqlite3DebugPrintf(const char*, ...);
+#endif
+#if defined(SQLITE_TEST)
+SQLITE_PRIVATE   void *sqlite3TestTextToPtr(const char*);
+#endif
+
+#if defined(SQLITE_DEBUG)
+SQLITE_PRIVATE   void sqlite3TreeViewLine(TreeView*, const char *zFormat, ...);
+SQLITE_PRIVATE   void sqlite3TreeViewExpr(TreeView*, const Expr*, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewBareExprList(TreeView*, const ExprList*, const char*);
+SQLITE_PRIVATE   void sqlite3TreeViewExprList(TreeView*, const ExprList*, u8, const char*);
+SQLITE_PRIVATE   void sqlite3TreeViewBareIdList(TreeView*, const IdList*, const char*);
+SQLITE_PRIVATE   void sqlite3TreeViewIdList(TreeView*, const IdList*, u8, const char*);
+SQLITE_PRIVATE   void sqlite3TreeViewColumnList(TreeView*, const Column*, int, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewSrcList(TreeView*, const SrcList*);
+SQLITE_PRIVATE   void sqlite3TreeViewSelect(TreeView*, const Select*, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewWith(TreeView*, const With*, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewUpsert(TreeView*, const Upsert*, u8);
+#if TREETRACE_ENABLED
+SQLITE_PRIVATE   void sqlite3TreeViewDelete(const With*, const SrcList*, const Expr*,
+                             const ExprList*,const Expr*, const Trigger*);
+SQLITE_PRIVATE   void sqlite3TreeViewInsert(const With*, const SrcList*,
+                             const IdList*, const Select*, const ExprList*,
+                             int, const Upsert*, const Trigger*);
+SQLITE_PRIVATE   void sqlite3TreeViewUpdate(const With*, const SrcList*, const ExprList*,
+                             const Expr*, int, const ExprList*, const Expr*,
+                             const Upsert*, const Trigger*);
+#endif
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE   void sqlite3TreeViewTriggerStep(TreeView*, const TriggerStep*, u8, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewTrigger(TreeView*, const Trigger*, u8, u8);
+#endif
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE   void sqlite3TreeViewWindow(TreeView*, const Window*, u8);
+SQLITE_PRIVATE   void sqlite3TreeViewWinFunc(TreeView*, const Window*, u8);
+#endif
+SQLITE_PRIVATE   void sqlite3ShowExpr(const Expr*);
+SQLITE_PRIVATE   void sqlite3ShowExprList(const ExprList*);
+SQLITE_PRIVATE   void sqlite3ShowIdList(const IdList*);
+SQLITE_PRIVATE   void sqlite3ShowSrcList(const SrcList*);
+SQLITE_PRIVATE   void sqlite3ShowSelect(const Select*);
+SQLITE_PRIVATE   void sqlite3ShowWith(const With*);
+SQLITE_PRIVATE   void sqlite3ShowUpsert(const Upsert*);
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE   void sqlite3ShowTriggerStep(const TriggerStep*);
+SQLITE_PRIVATE   void sqlite3ShowTriggerStepList(const TriggerStep*);
+SQLITE_PRIVATE   void sqlite3ShowTrigger(const Trigger*);
+SQLITE_PRIVATE   void sqlite3ShowTriggerList(const Trigger*);
+#endif
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE   void sqlite3ShowWindow(const Window*);
+SQLITE_PRIVATE   void sqlite3ShowWinFunc(const Window*);
+#endif
+#endif
+
+SQLITE_PRIVATE void sqlite3SetString(char **, sqlite3*, const char*);
+SQLITE_PRIVATE void sqlite3ProgressCheck(Parse*);
+SQLITE_PRIVATE void sqlite3ErrorMsg(Parse*, const char*, ...);
+SQLITE_PRIVATE int sqlite3ErrorToParser(sqlite3*,int);
+SQLITE_PRIVATE void sqlite3Dequote(char*);
+SQLITE_PRIVATE void sqlite3DequoteExpr(Expr*);
+SQLITE_PRIVATE void sqlite3DequoteToken(Token*);
+SQLITE_PRIVATE void sqlite3DequoteNumber(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3TokenInit(Token*,char*);
+SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char*, int);
+SQLITE_PRIVATE int sqlite3RunParser(Parse*, const char*);
+SQLITE_PRIVATE void sqlite3FinishCoding(Parse*);
+SQLITE_PRIVATE int sqlite3GetTempReg(Parse*);
+SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse*,int);
+SQLITE_PRIVATE int sqlite3GetTempRange(Parse*,int);
+SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse*,int,int);
+SQLITE_PRIVATE void sqlite3ClearTempRegCache(Parse*);
+SQLITE_PRIVATE void sqlite3TouchRegister(Parse*,int);
+#if defined(SQLITE_ENABLE_STAT4) || defined(SQLITE_DEBUG)
+SQLITE_PRIVATE int sqlite3FirstAvailableRegister(Parse*,int);
+#endif
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3NoTempsInRange(Parse*,int,int);
+#endif
+SQLITE_PRIVATE Expr *sqlite3ExprAlloc(sqlite3*,int,const Token*,int);
+SQLITE_PRIVATE Expr *sqlite3Expr(sqlite3*,int,const char*);
+SQLITE_PRIVATE void sqlite3ExprAttachSubtrees(sqlite3*,Expr*,Expr*,Expr*);
+SQLITE_PRIVATE Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*);
+SQLITE_PRIVATE void sqlite3PExprAddSelect(Parse*, Expr*, Select*);
+SQLITE_PRIVATE Expr *sqlite3ExprAnd(Parse*,Expr*, Expr*);
+SQLITE_PRIVATE Expr *sqlite3ExprSimplifiedAndOr(Expr*);
+SQLITE_PRIVATE Expr *sqlite3ExprFunction(Parse*,ExprList*, const Token*, int);
+SQLITE_PRIVATE void sqlite3ExprAddFunctionOrderBy(Parse*,Expr*,ExprList*);
+SQLITE_PRIVATE void sqlite3ExprOrderByAggregateError(Parse*,Expr*);
+SQLITE_PRIVATE void sqlite3ExprFunctionUsable(Parse*,const Expr*,const FuncDef*);
+SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse*, Expr*, u32);
+SQLITE_PRIVATE void sqlite3ExprDelete(sqlite3*, Expr*);
+SQLITE_PRIVATE void sqlite3ExprDeleteGeneric(sqlite3*,void*);
+SQLITE_PRIVATE int sqlite3ExprDeferredDelete(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3ExprUnmapAndDelete(Parse*, Expr*);
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(Parse*,ExprList*,Expr*);
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppendVector(Parse*,ExprList*,IdList*,Expr*);
+SQLITE_PRIVATE Select *sqlite3ExprListToValues(Parse*, int, ExprList*);
+SQLITE_PRIVATE void sqlite3ExprListSetSortOrder(ExprList*,int,int);
+SQLITE_PRIVATE void sqlite3ExprListSetName(Parse*,ExprList*,const Token*,int);
+SQLITE_PRIVATE void sqlite3ExprListSetSpan(Parse*,ExprList*,const char*,const char*);
+SQLITE_PRIVATE void sqlite3ExprListDelete(sqlite3*, ExprList*);
+SQLITE_PRIVATE void sqlite3ExprListDeleteGeneric(sqlite3*,void*);
+SQLITE_PRIVATE u32 sqlite3ExprListFlags(const ExprList*);
+SQLITE_PRIVATE int sqlite3IndexHasDuplicateRootPage(Index*);
+SQLITE_PRIVATE int sqlite3Init(sqlite3*, char**);
+SQLITE_PRIVATE int sqlite3InitCallback(void*, int, char**, char**);
+SQLITE_PRIVATE int sqlite3InitOne(sqlite3*, int, char**, u32);
+SQLITE_PRIVATE void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+SQLITE_PRIVATE Module *sqlite3PragmaVtabRegister(sqlite3*,const char *zName);
+#endif
+SQLITE_PRIVATE void sqlite3ResetAllSchemasOfConnection(sqlite3*);
+SQLITE_PRIVATE void sqlite3ResetOneSchema(sqlite3*,int);
+SQLITE_PRIVATE void sqlite3CollapseDatabaseArray(sqlite3*);
+SQLITE_PRIVATE void sqlite3CommitInternalChanges(sqlite3*);
+SQLITE_PRIVATE void sqlite3ColumnSetExpr(Parse*,Table*,Column*,Expr*);
+SQLITE_PRIVATE Expr *sqlite3ColumnExpr(Table*,Column*);
+SQLITE_PRIVATE void sqlite3ColumnSetColl(sqlite3*,Column*,const char*zColl);
+SQLITE_PRIVATE const char *sqlite3ColumnColl(Column*);
+SQLITE_PRIVATE void sqlite3DeleteColumnNames(sqlite3*,Table*);
+SQLITE_PRIVATE void sqlite3GenerateColumnNames(Parse *pParse, Select *pSelect);
+SQLITE_PRIVATE int sqlite3ColumnsFromExprList(Parse*,ExprList*,i16*,Column**);
+SQLITE_PRIVATE void sqlite3SubqueryColumnTypes(Parse*,Table*,Select*,char);
+SQLITE_PRIVATE Table *sqlite3ResultSetOfSelect(Parse*,Select*,char);
+SQLITE_PRIVATE void sqlite3OpenSchemaTable(Parse *, int);
+SQLITE_PRIVATE Index *sqlite3PrimaryKeyIndex(Table*);
+SQLITE_PRIVATE i16 sqlite3TableColumnToIndex(Index*, i16);
+#ifdef SQLITE_OMIT_GENERATED_COLUMNS
+# define sqlite3TableColumnToStorage(T,X) (X)  /* No-op pass-through */
+# define sqlite3StorageColumnToTable(T,X) (X)  /* No-op pass-through */
+#else
+SQLITE_PRIVATE   i16 sqlite3TableColumnToStorage(Table*, i16);
+SQLITE_PRIVATE   i16 sqlite3StorageColumnToTable(Table*, i16);
+#endif
+SQLITE_PRIVATE void sqlite3StartTable(Parse*,Token*,Token*,int,int,int,int);
+#if SQLITE_ENABLE_HIDDEN_COLUMNS
+SQLITE_PRIVATE   void sqlite3ColumnPropertiesFromName(Table*, Column*);
+#else
+# define sqlite3ColumnPropertiesFromName(T,C) /* no-op */
+#endif
+SQLITE_PRIVATE void sqlite3AddColumn(Parse*,Token,Token);
+SQLITE_PRIVATE void sqlite3AddNotNull(Parse*, int);
+SQLITE_PRIVATE void sqlite3AddPrimaryKey(Parse*, ExprList*, int, int, int);
+SQLITE_PRIVATE void sqlite3AddCheckConstraint(Parse*, Expr*, const char*, const char*);
+SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse*,Expr*,const char*,const char*);
+SQLITE_PRIVATE void sqlite3AddCollateType(Parse*, Token*);
+SQLITE_PRIVATE void sqlite3AddGenerated(Parse*,Expr*,Token*);
+SQLITE_PRIVATE void sqlite3EndTable(Parse*,Token*,Token*,u32,Select*);
+SQLITE_PRIVATE void sqlite3AddReturning(Parse*,ExprList*);
+SQLITE_PRIVATE int sqlite3ParseUri(const char*,const char*,unsigned int*,
+                    sqlite3_vfs**,char**,char **);
+#define sqlite3CodecQueryParameters(A,B,C) 0
+SQLITE_PRIVATE Btree *sqlite3DbNameToBtree(sqlite3*,const char*);
+
+#ifdef SQLITE_UNTESTABLE
+# define sqlite3FaultSim(X) SQLITE_OK
+#else
+SQLITE_PRIVATE   int sqlite3FaultSim(int);
+#endif
+
+SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32);
+SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec*, u32);
+SQLITE_PRIVATE int sqlite3BitvecTestNotNull(Bitvec*, u32);
+SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec*, u32);
+SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec*, u32, void*);
+SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec*);
+SQLITE_PRIVATE u32 sqlite3BitvecSize(Bitvec*);
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int,int*);
+#endif
+
+SQLITE_PRIVATE RowSet *sqlite3RowSetInit(sqlite3*);
+SQLITE_PRIVATE void sqlite3RowSetDelete(void*);
+SQLITE_PRIVATE void sqlite3RowSetClear(void*);
+SQLITE_PRIVATE void sqlite3RowSetInsert(RowSet*, i64);
+SQLITE_PRIVATE int sqlite3RowSetTest(RowSet*, int iBatch, i64);
+SQLITE_PRIVATE int sqlite3RowSetNext(RowSet*, i64*);
+
+SQLITE_PRIVATE void sqlite3CreateView(Parse*,Token*,Token*,Token*,ExprList*,Select*,int,int);
+
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+SQLITE_PRIVATE   int sqlite3ViewGetColumnNames(Parse*,Table*);
+#else
+# define sqlite3ViewGetColumnNames(A,B) 0
+#endif
+
+#if SQLITE_MAX_ATTACHED>30
+SQLITE_PRIVATE   int sqlite3DbMaskAllZero(yDbMask);
+#endif
+SQLITE_PRIVATE void sqlite3DropTable(Parse*, SrcList*, int, int);
+SQLITE_PRIVATE void sqlite3CodeDropTable(Parse*, Table*, int, int);
+SQLITE_PRIVATE void sqlite3DeleteTable(sqlite3*, Table*);
+SQLITE_PRIVATE void sqlite3DeleteTableGeneric(sqlite3*, void*);
+SQLITE_PRIVATE void sqlite3FreeIndex(sqlite3*, Index*);
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+SQLITE_PRIVATE   void sqlite3AutoincrementBegin(Parse *pParse);
+SQLITE_PRIVATE   void sqlite3AutoincrementEnd(Parse *pParse);
+#else
+# define sqlite3AutoincrementBegin(X)
+# define sqlite3AutoincrementEnd(X)
+#endif
+SQLITE_PRIVATE void sqlite3Insert(Parse*, SrcList*, Select*, IdList*, int, Upsert*);
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+SQLITE_PRIVATE   void sqlite3ComputeGeneratedColumns(Parse*, int, Table*);
+#endif
+SQLITE_PRIVATE void *sqlite3ArrayAllocate(sqlite3*,void*,int,int*,int*);
+SQLITE_PRIVATE IdList *sqlite3IdListAppend(Parse*, IdList*, Token*);
+SQLITE_PRIVATE int sqlite3IdListIndex(IdList*,const char*);
+SQLITE_PRIVATE SrcList *sqlite3SrcListEnlarge(Parse*, SrcList*, int, int);
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendList(Parse *pParse, SrcList *p1, SrcList *p2);
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppend(Parse*, SrcList*, Token*, Token*);
+SQLITE_PRIVATE void sqlite3SubqueryDelete(sqlite3*,Subquery*);
+SQLITE_PRIVATE Select *sqlite3SubqueryDetach(sqlite3*,SrcItem*);
+SQLITE_PRIVATE int sqlite3SrcItemAttachSubquery(Parse*, SrcItem*, Select*, int);
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendFromTerm(Parse*, SrcList*, Token*, Token*,
+                                      Token*, Select*, OnOrUsing*);
+SQLITE_PRIVATE void sqlite3SrcListIndexedBy(Parse *, SrcList *, Token *);
+SQLITE_PRIVATE void sqlite3SrcListFuncArgs(Parse*, SrcList*, ExprList*);
+SQLITE_PRIVATE int sqlite3IndexedByLookup(Parse *, SrcItem *);
+SQLITE_PRIVATE void sqlite3SrcListShiftJoinType(Parse*,SrcList*);
+SQLITE_PRIVATE void sqlite3SrcListAssignCursors(Parse*, SrcList*);
+SQLITE_PRIVATE void sqlite3IdListDelete(sqlite3*, IdList*);
+SQLITE_PRIVATE void sqlite3ClearOnOrUsing(sqlite3*, OnOrUsing*);
+SQLITE_PRIVATE void sqlite3SrcListDelete(sqlite3*, SrcList*);
+SQLITE_PRIVATE Index *sqlite3AllocateIndexObject(sqlite3*,i16,int,char**);
+SQLITE_PRIVATE void sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
+                          Expr*, int, int, u8);
+SQLITE_PRIVATE void sqlite3DropIndex(Parse*, SrcList*, int);
+SQLITE_PRIVATE int sqlite3Select(Parse*, Select*, SelectDest*);
+SQLITE_PRIVATE Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
+                         Expr*,ExprList*,u32,Expr*);
+SQLITE_PRIVATE void sqlite3SelectDelete(sqlite3*, Select*);
+SQLITE_PRIVATE void sqlite3SelectDeleteGeneric(sqlite3*,void*);
+SQLITE_PRIVATE Table *sqlite3SrcListLookup(Parse*, SrcList*);
+SQLITE_PRIVATE int sqlite3IsReadOnly(Parse*, Table*, Trigger*);
+SQLITE_PRIVATE void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
+#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
+SQLITE_PRIVATE Expr *sqlite3LimitWhere(Parse*,SrcList*,Expr*,ExprList*,Expr*,char*);
+#endif
+SQLITE_PRIVATE void sqlite3CodeChangeCount(Vdbe*,int,const char*);
+SQLITE_PRIVATE void sqlite3DeleteFrom(Parse*, SrcList*, Expr*, ExprList*, Expr*);
+SQLITE_PRIVATE void sqlite3Update(Parse*, SrcList*, ExprList*,Expr*,int,ExprList*,Expr*,
+                   Upsert*);
+SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(Parse*,SrcList*,Expr*,ExprList*,
+                             ExprList*,Select*,u16,int);
+SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo*);
+SQLITE_PRIVATE LogEst sqlite3WhereOutputRowCount(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereIsDistinct(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereIsOrdered(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereOrderByLimitOptLabel(WhereInfo*);
+SQLITE_PRIVATE void sqlite3WhereMinMaxOptEarlyOut(Vdbe*,WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereIsSorted(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereContinueLabel(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereBreakLabel(WhereInfo*);
+SQLITE_PRIVATE int sqlite3WhereOkOnePass(WhereInfo*, int*);
+#define ONEPASS_OFF      0        /* Use of ONEPASS not allowed */
+#define ONEPASS_SINGLE   1        /* ONEPASS valid for a single row update */
+#define ONEPASS_MULTI    2        /* ONEPASS is valid for multiple rows */
+SQLITE_PRIVATE int sqlite3WhereUsesDeferredSeek(WhereInfo*);
+SQLITE_PRIVATE void sqlite3ExprCodeLoadIndexColumn(Parse*, Index*, int, int, int);
+SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, u8);
+SQLITE_PRIVATE void sqlite3ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
+SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse*, int, int, int);
+SQLITE_PRIVATE void sqlite3ExprToRegister(Expr *pExpr, int iReg);
+SQLITE_PRIVATE void sqlite3ExprCode(Parse*, Expr*, int);
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+SQLITE_PRIVATE void sqlite3ExprCodeGeneratedColumn(Parse*, Table*, Column*, int);
+#endif
+SQLITE_PRIVATE void sqlite3ExprCodeCopy(Parse*, Expr*, int);
+SQLITE_PRIVATE void sqlite3ExprCodeFactorable(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCodeRunJustOnce(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
+SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCodeExprList(Parse*, ExprList*, int, int, u8);
+#define SQLITE_ECEL_DUP      0x01  /* Deep, not shallow copies */
+#define SQLITE_ECEL_FACTOR   0x02  /* Factor out constant terms */
+#define SQLITE_ECEL_REF      0x04  /* Use ExprList.u.x.iOrderByCol */
+#define SQLITE_ECEL_OMITREF  0x08  /* Omit if ExprList.u.x.iOrderByCol */
+SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
+SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
+SQLITE_PRIVATE void sqlite3ExprIfFalseDup(Parse*, Expr*, int, int);
+SQLITE_PRIVATE Table *sqlite3FindTable(sqlite3*,const char*, const char*);
+#define LOCATE_VIEW    0x01
+#define LOCATE_NOERR   0x02
+SQLITE_PRIVATE Table *sqlite3LocateTable(Parse*,u32 flags,const char*, const char*);
+SQLITE_PRIVATE const char *sqlite3PreferredTableName(const char*);
+SQLITE_PRIVATE Table *sqlite3LocateTableItem(Parse*,u32 flags,SrcItem *);
+SQLITE_PRIVATE Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);
+SQLITE_PRIVATE void sqlite3Vacuum(Parse*,Token*,Expr*);
+SQLITE_PRIVATE int sqlite3RunVacuum(char**, sqlite3*, int, sqlite3_value*);
+SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3*, const Token*);
+SQLITE_PRIVATE int sqlite3ExprCompare(const Parse*,const Expr*,const Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprCompareSkip(Expr*,Expr*,int);
+SQLITE_PRIVATE int sqlite3ExprListCompare(const ExprList*,const ExprList*, int);
+SQLITE_PRIVATE int sqlite3ExprImpliesExpr(const Parse*,const Expr*,const Expr*, int);
+SQLITE_PRIVATE int sqlite3ExprImpliesNonNullRow(Expr*,int,int);
+SQLITE_PRIVATE void sqlite3AggInfoPersistWalkerInit(Walker*,Parse*);
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
+SQLITE_PRIVATE int sqlite3ExprCoveredByIndex(Expr*, int iCur, Index *pIdx);
+SQLITE_PRIVATE int sqlite3ReferencesSrcList(Parse*, Expr*, SrcList*);
+SQLITE_PRIVATE Vdbe *sqlite3GetVdbe(Parse*);
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE void sqlite3PrngSaveState(void);
+SQLITE_PRIVATE void sqlite3PrngRestoreState(void);
+#endif
+SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3*,int);
+SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse*, int);
+SQLITE_PRIVATE void sqlite3CodeVerifyNamedSchema(Parse*, const char *zDb);
+SQLITE_PRIVATE void sqlite3BeginTransaction(Parse*, int);
+SQLITE_PRIVATE void sqlite3EndTransaction(Parse*,int);
+SQLITE_PRIVATE void sqlite3Savepoint(Parse*, int, Token*);
+SQLITE_PRIVATE void sqlite3CloseSavepoints(sqlite3 *);
+SQLITE_PRIVATE void sqlite3LeaveMutexAndCloseZombie(sqlite3*);
+SQLITE_PRIVATE u32 sqlite3IsTrueOrFalse(const char*);
+SQLITE_PRIVATE int sqlite3ExprIdToTrueFalse(Expr*);
+SQLITE_PRIVATE int sqlite3ExprTruthValue(const Expr*);
+SQLITE_PRIVATE int sqlite3ExprIsConstant(Parse*,Expr*);
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr*, u8);
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrGroupBy(Parse*, Expr*, ExprList*);
+SQLITE_PRIVATE int sqlite3ExprIsSingleTableConstraint(Expr*,const SrcList*,int,int);
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+SQLITE_PRIVATE int sqlite3ExprContainsSubquery(Expr*);
+#endif
+SQLITE_PRIVATE int sqlite3ExprIsInteger(const Expr*, int*, Parse*);
+SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr*);
+SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr*, char);
+SQLITE_PRIVATE int sqlite3IsRowid(const char*);
+SQLITE_PRIVATE const char *sqlite3RowidAlias(Table *pTab);
+SQLITE_PRIVATE void sqlite3GenerateRowDelete(
+    Parse*,Table*,Trigger*,int,int,int,i16,u8,u8,u8,int);
+SQLITE_PRIVATE void sqlite3GenerateRowIndexDelete(Parse*, Table*, int, int, int*, int);
+SQLITE_PRIVATE int sqlite3GenerateIndexKey(Parse*, Index*, int, int, int, int*,Index*,int);
+SQLITE_PRIVATE void sqlite3ResolvePartIdxLabel(Parse*,int);
+SQLITE_PRIVATE int sqlite3ExprReferencesUpdatedColumn(Expr*,int*,int);
+SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(Parse*,Table*,int*,int,int,int,int,
+                                     u8,u8,int,int*,int*,Upsert*);
+#ifdef SQLITE_ENABLE_NULL_TRIM
+SQLITE_PRIVATE   void sqlite3SetMakeRecordP5(Vdbe*,Table*);
+#else
+# define sqlite3SetMakeRecordP5(A,B)
+#endif
+SQLITE_PRIVATE void sqlite3CompleteInsertion(Parse*,Table*,int,int,int,int*,int,int,int);
+SQLITE_PRIVATE int sqlite3OpenTableAndIndices(Parse*, Table*, int, u8, int, u8*, int*, int*);
+SQLITE_PRIVATE void sqlite3BeginWriteOperation(Parse*, int, int);
+SQLITE_PRIVATE void sqlite3MultiWrite(Parse*);
+SQLITE_PRIVATE void sqlite3MayAbort(Parse*);
+SQLITE_PRIVATE void sqlite3HaltConstraint(Parse*, int, int, char*, i8, u8);
+SQLITE_PRIVATE void sqlite3UniqueConstraint(Parse*, int, Index*);
+SQLITE_PRIVATE void sqlite3RowidConstraint(Parse*, int, Table*);
+SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3*,const Expr*,int);
+SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3*,const ExprList*,int);
+SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3*,const SrcList*,int);
+SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3*,const IdList*);
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3*,const Select*,int);
+SQLITE_PRIVATE FuncDef *sqlite3FunctionSearch(int,const char*);
+SQLITE_PRIVATE void sqlite3InsertBuiltinFuncs(FuncDef*,int);
+SQLITE_PRIVATE FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,u8,u8);
+SQLITE_PRIVATE void sqlite3QuoteValue(StrAccum*,sqlite3_value*);
+SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(void);
+SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void);
+SQLITE_PRIVATE void sqlite3RegisterJsonFunctions(void);
+SQLITE_PRIVATE void sqlite3RegisterPerConnectionBuiltinFunctions(sqlite3*);
+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_JSON)
+SQLITE_PRIVATE   int sqlite3JsonTableFunctions(sqlite3*);
+#endif
+SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3*);
+SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3*);
+SQLITE_PRIVATE void sqlite3ChangeCookie(Parse*, int);
+SQLITE_PRIVATE With *sqlite3WithDup(sqlite3 *db, With *p);
+
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+SQLITE_PRIVATE void sqlite3MaterializeView(Parse*, Table*, Expr*, ExprList*,Expr*,int);
+#endif
+
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE   void sqlite3BeginTrigger(Parse*, Token*,Token*,int,int,IdList*,SrcList*,
+                           Expr*,int, int);
+SQLITE_PRIVATE   void sqlite3FinishTrigger(Parse*, TriggerStep*, Token*);
+SQLITE_PRIVATE   void sqlite3DropTrigger(Parse*, SrcList*, int);
+SQLITE_PRIVATE   void sqlite3DropTriggerPtr(Parse*, Trigger*);
+SQLITE_PRIVATE   Trigger *sqlite3TriggersExist(Parse *, Table*, int, ExprList*, int *pMask);
+SQLITE_PRIVATE   Trigger *sqlite3TriggerList(Parse *, Table *);
+SQLITE_PRIVATE   void sqlite3CodeRowTrigger(Parse*, Trigger *, int, ExprList*, int, Table *,
+                            int, int, int);
+SQLITE_PRIVATE   void sqlite3CodeRowTriggerDirect(Parse *, Trigger *, Table *, int, int, int);
+  void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);
+SQLITE_PRIVATE   void sqlite3DeleteTriggerStep(sqlite3*, TriggerStep*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerSelectStep(sqlite3*,Select*,
+                                        const char*,const char*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerInsertStep(Parse*,Token*, IdList*,
+                                        Select*,u8,Upsert*,
+                                        const char*,const char*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerUpdateStep(Parse*,Token*,SrcList*,ExprList*,
+                                        Expr*, u8, const char*,const char*);
+SQLITE_PRIVATE   TriggerStep *sqlite3TriggerDeleteStep(Parse*,Token*, Expr*,
+                                        const char*,const char*);
+SQLITE_PRIVATE   void sqlite3DeleteTrigger(sqlite3*, Trigger*);
+SQLITE_PRIVATE   void sqlite3UnlinkAndDeleteTrigger(sqlite3*,int,const char*);
+SQLITE_PRIVATE   u32 sqlite3TriggerColmask(Parse*,Trigger*,ExprList*,int,int,Table*,int);
+SQLITE_PRIVATE   SrcList *sqlite3TriggerStepSrc(Parse*, TriggerStep*);
+# define sqlite3ParseToplevel(p) ((p)->pToplevel ? (p)->pToplevel : (p))
+# define sqlite3IsToplevel(p) ((p)->pToplevel==0)
+#else
+# define sqlite3TriggersExist(B,C,D,E,F) 0
+# define sqlite3DeleteTrigger(A,B)
+# define sqlite3DropTriggerPtr(A,B)
+# define sqlite3UnlinkAndDeleteTrigger(A,B,C)
+# define sqlite3CodeRowTrigger(A,B,C,D,E,F,G,H,I)
+# define sqlite3CodeRowTriggerDirect(A,B,C,D,E,F)
+# define sqlite3TriggerList(X, Y) 0
+# define sqlite3ParseToplevel(p) p
+# define sqlite3IsToplevel(p) 1
+# define sqlite3TriggerColmask(A,B,C,D,E,F,G) 0
+# define sqlite3TriggerStepSrc(A,B) 0
+#endif
+
+SQLITE_PRIVATE int sqlite3JoinType(Parse*, Token*, Token*, Token*);
+SQLITE_PRIVATE int sqlite3ColumnIndex(Table *pTab, const char *zCol);
+SQLITE_PRIVATE void sqlite3SrcItemColumnUsed(SrcItem*,int);
+SQLITE_PRIVATE void sqlite3SetJoinExpr(Expr*,int,u32);
+SQLITE_PRIVATE void sqlite3CreateForeignKey(Parse*, ExprList*, Token*, ExprList*, int);
+SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse*, int);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+SQLITE_PRIVATE   void sqlite3AuthRead(Parse*,Expr*,Schema*,SrcList*);
+SQLITE_PRIVATE   int sqlite3AuthCheck(Parse*,int, const char*, const char*, const char*);
+SQLITE_PRIVATE   void sqlite3AuthContextPush(Parse*, AuthContext*, const char*);
+SQLITE_PRIVATE   void sqlite3AuthContextPop(AuthContext*);
+SQLITE_PRIVATE   int sqlite3AuthReadCol(Parse*, const char *, const char *, int);
+#else
+# define sqlite3AuthRead(a,b,c,d)
+# define sqlite3AuthCheck(a,b,c,d,e)    SQLITE_OK
+# define sqlite3AuthContextPush(a,b,c)
+# define sqlite3AuthContextPop(a)  ((void)(a))
+#endif
+SQLITE_PRIVATE int sqlite3DbIsNamed(sqlite3 *db, int iDb, const char *zName);
+SQLITE_PRIVATE void sqlite3Attach(Parse*, Expr*, Expr*, Expr*);
+SQLITE_PRIVATE void sqlite3Detach(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3FixInit(DbFixer*, Parse*, int, const char*, const Token*);
+SQLITE_PRIVATE int sqlite3FixSrcList(DbFixer*, SrcList*);
+SQLITE_PRIVATE int sqlite3FixSelect(DbFixer*, Select*);
+SQLITE_PRIVATE int sqlite3FixExpr(DbFixer*, Expr*);
+SQLITE_PRIVATE int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);
+
+SQLITE_PRIVATE int sqlite3RealSameAsInt(double,sqlite3_int64);
+SQLITE_PRIVATE i64 sqlite3RealToI64(double);
+SQLITE_PRIVATE int sqlite3Int64ToText(i64,char*);
+SQLITE_PRIVATE int sqlite3AtoF(const char *z, double*, int, u8);
+SQLITE_PRIVATE int sqlite3GetInt32(const char *, int*);
+SQLITE_PRIVATE int sqlite3GetUInt32(const char*, u32*);
+SQLITE_PRIVATE int sqlite3Atoi(const char*);
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_PRIVATE int sqlite3Utf16ByteLen(const void *pData, int nByte, int nChar);
+#endif
+SQLITE_PRIVATE int sqlite3Utf8CharLen(const char *pData, int nByte);
+SQLITE_PRIVATE u32 sqlite3Utf8Read(const u8**);
+SQLITE_PRIVATE int sqlite3Utf8ReadLimited(const u8*, int, u32*);
+SQLITE_PRIVATE LogEst sqlite3LogEst(u64);
+SQLITE_PRIVATE LogEst sqlite3LogEstAdd(LogEst,LogEst);
+SQLITE_PRIVATE LogEst sqlite3LogEstFromDouble(double);
+SQLITE_PRIVATE u64 sqlite3LogEstToInt(LogEst);
+SQLITE_PRIVATE VList *sqlite3VListAdd(sqlite3*,VList*,const char*,int,int);
+SQLITE_PRIVATE const char *sqlite3VListNumToName(VList*,int);
+SQLITE_PRIVATE int sqlite3VListNameToNum(VList*,const char*,int);
+
+/*
+** Routines to read and write variable-length integers.  These used to
+** be defined locally, but now we use the varint routines in the util.c
+** file.
+*/
+SQLITE_PRIVATE int sqlite3PutVarint(unsigned char*, u64);
+SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *, u64 *);
+SQLITE_PRIVATE u8 sqlite3GetVarint32(const unsigned char *, u32 *);
+SQLITE_PRIVATE int sqlite3VarintLen(u64 v);
+
+/*
+** The common case is for a varint to be a single byte.  They following
+** macros handle the common case without a procedure call, but then call
+** the procedure for larger varints.
+*/
+#define getVarint32(A,B)  \
+  (u8)((*(A)<(u8)0x80)?((B)=(u32)*(A)),1:sqlite3GetVarint32((A),(u32 *)&(B)))
+#define getVarint32NR(A,B) \
+  B=(u32)*(A);if(B>=0x80)sqlite3GetVarint32((A),(u32*)&(B))
+#define putVarint32(A,B)  \
+  (u8)(((u32)(B)<(u32)0x80)?(*(A)=(unsigned char)(B)),1:\
+  sqlite3PutVarint((A),(B)))
+#define getVarint    sqlite3GetVarint
+#define putVarint    sqlite3PutVarint
+
+
+SQLITE_PRIVATE const char *sqlite3IndexAffinityStr(sqlite3*, Index*);
+SQLITE_PRIVATE char *sqlite3TableAffinityStr(sqlite3*,const Table*);
+SQLITE_PRIVATE void sqlite3TableAffinity(Vdbe*, Table*, int);
+SQLITE_PRIVATE char sqlite3CompareAffinity(const Expr *pExpr, char aff2);
+SQLITE_PRIVATE int sqlite3IndexAffinityOk(const Expr *pExpr, char idx_affinity);
+SQLITE_PRIVATE char sqlite3TableColumnAffinity(const Table*,int);
+SQLITE_PRIVATE char sqlite3ExprAffinity(const Expr *pExpr);
+SQLITE_PRIVATE int sqlite3ExprDataType(const Expr *pExpr);
+SQLITE_PRIVATE int sqlite3Atoi64(const char*, i64*, int, u8);
+SQLITE_PRIVATE int sqlite3DecOrHexToI64(const char*, i64*);
+SQLITE_PRIVATE void sqlite3ErrorWithMsg(sqlite3*, int, const char*,...);
+SQLITE_PRIVATE void sqlite3Error(sqlite3*,int);
+SQLITE_PRIVATE void sqlite3ErrorClear(sqlite3*);
+SQLITE_PRIVATE void sqlite3SystemError(sqlite3*,int);
+#if !defined(SQLITE_OMIT_BLOB_LITERAL)
+SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3*, const char *z, int n);
+#endif
+SQLITE_PRIVATE u8 sqlite3HexToInt(int h);
+SQLITE_PRIVATE int sqlite3TwoPartName(Parse *, Token *, Token *, Token **);
+
+#if defined(SQLITE_NEED_ERR_NAME)
+SQLITE_PRIVATE const char *sqlite3ErrName(int);
+#endif
+
+#ifndef SQLITE_OMIT_DESERIALIZE
+SQLITE_PRIVATE int sqlite3MemdbInit(void);
+SQLITE_PRIVATE int sqlite3IsMemdb(const sqlite3_vfs*);
+#else
+# define sqlite3IsMemdb(X) 0
+#endif
+
+SQLITE_PRIVATE const char *sqlite3ErrStr(int);
+SQLITE_PRIVATE int sqlite3ReadSchema(Parse *pParse);
+SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(sqlite3*,u8 enc, const char*,int);
+SQLITE_PRIVATE int sqlite3IsBinary(const CollSeq*);
+SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char*zName);
+SQLITE_PRIVATE void sqlite3SetTextEncoding(sqlite3 *db, u8);
+SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, const Expr *pExpr);
+SQLITE_PRIVATE CollSeq *sqlite3ExprNNCollSeq(Parse *pParse, const Expr *pExpr);
+SQLITE_PRIVATE int sqlite3ExprCollSeqMatch(Parse*,const Expr*,const Expr*);
+SQLITE_PRIVATE Expr *sqlite3ExprAddCollateToken(const Parse *pParse, Expr*, const Token*, int);
+SQLITE_PRIVATE Expr *sqlite3ExprAddCollateString(const Parse*,Expr*,const char*);
+SQLITE_PRIVATE Expr *sqlite3ExprSkipCollate(Expr*);
+SQLITE_PRIVATE Expr *sqlite3ExprSkipCollateAndLikely(Expr*);
+SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *, CollSeq *);
+SQLITE_PRIVATE int sqlite3WritableSchema(sqlite3*);
+SQLITE_PRIVATE int sqlite3CheckObjectName(Parse*, const char*,const char*,const char*);
+SQLITE_PRIVATE void sqlite3VdbeSetChanges(sqlite3 *, i64);
+SQLITE_PRIVATE int sqlite3AddInt64(i64*,i64);
+SQLITE_PRIVATE int sqlite3SubInt64(i64*,i64);
+SQLITE_PRIVATE int sqlite3MulInt64(i64*,i64);
+SQLITE_PRIVATE int sqlite3AbsInt32(int);
+#ifdef SQLITE_ENABLE_8_3_NAMES
+SQLITE_PRIVATE void sqlite3FileSuffix3(const char*, char*);
+#else
+# define sqlite3FileSuffix3(X,Y)
+#endif
+SQLITE_PRIVATE u8 sqlite3GetBoolean(const char *z,u8);
+
+SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value*, u8);
+SQLITE_PRIVATE int sqlite3ValueIsOfClass(const sqlite3_value*, void(*)(void*));
+SQLITE_PRIVATE int sqlite3ValueBytes(sqlite3_value*, u8);
+SQLITE_PRIVATE void sqlite3ValueSetStr(sqlite3_value*, int, const void *,u8,
+                        void(*)(void*));
+SQLITE_PRIVATE void sqlite3ValueSetNull(sqlite3_value*);
+SQLITE_PRIVATE void sqlite3ValueFree(sqlite3_value*);
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE void sqlite3ResultIntReal(sqlite3_context*);
+#endif
+SQLITE_PRIVATE sqlite3_value *sqlite3ValueNew(sqlite3 *);
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *, const void*, int, u8);
+#endif
+SQLITE_PRIVATE int sqlite3ValueFromExpr(sqlite3 *, const Expr *, u8, u8, sqlite3_value **);
+SQLITE_PRIVATE void sqlite3ValueApplyAffinity(sqlite3_value *, u8, u8);
+#ifndef SQLITE_AMALGAMATION
+SQLITE_PRIVATE const unsigned char sqlite3OpcodeProperty[];
+SQLITE_PRIVATE const char sqlite3StrBINARY[];
+SQLITE_PRIVATE const unsigned char sqlite3StdTypeLen[];
+SQLITE_PRIVATE const char sqlite3StdTypeAffinity[];
+SQLITE_PRIVATE const char *sqlite3StdType[];
+SQLITE_PRIVATE const unsigned char sqlite3UpperToLower[];
+SQLITE_PRIVATE const unsigned char *sqlite3aLTb;
+SQLITE_PRIVATE const unsigned char *sqlite3aEQb;
+SQLITE_PRIVATE const unsigned char *sqlite3aGTb;
+SQLITE_PRIVATE const unsigned char sqlite3CtypeMap[];
+SQLITE_PRIVATE SQLITE_WSD struct Sqlite3Config sqlite3Config;
+SQLITE_PRIVATE FuncDefHash sqlite3BuiltinFunctions;
+#ifndef SQLITE_OMIT_WSD
+SQLITE_PRIVATE int sqlite3PendingByte;
+#endif
+#endif /* SQLITE_AMALGAMATION */
+#ifdef VDBE_PROFILE
+SQLITE_PRIVATE sqlite3_uint64 sqlite3NProfileCnt;
+#endif
+SQLITE_PRIVATE void sqlite3RootPageMoved(sqlite3*, int, Pgno, Pgno);
+SQLITE_PRIVATE void sqlite3Reindex(Parse*, Token*, Token*);
+SQLITE_PRIVATE void sqlite3AlterFunctions(void);
+SQLITE_PRIVATE void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
+SQLITE_PRIVATE void sqlite3AlterRenameColumn(Parse*, SrcList*, Token*, Token*);
+SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *, int *);
+SQLITE_PRIVATE void sqlite3NestedParse(Parse*, const char*, ...);
+SQLITE_PRIVATE void sqlite3ExpirePreparedStatements(sqlite3*, int);
+SQLITE_PRIVATE void sqlite3CodeRhsOfIN(Parse*, Expr*, int);
+SQLITE_PRIVATE int sqlite3CodeSubselect(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3SelectPrep(Parse*, Select*, NameContext*);
+SQLITE_PRIVATE int sqlite3ExpandSubquery(Parse*, SrcItem*);
+SQLITE_PRIVATE void sqlite3SelectWrongNumTermsError(Parse *pParse, Select *p);
+SQLITE_PRIVATE int sqlite3MatchEName(
+  const struct ExprList_item*,
+  const char*,
+  const char*,
+  const char*,
+  int*
+);
+SQLITE_PRIVATE Bitmask sqlite3ExprColUsed(Expr*);
+SQLITE_PRIVATE u8 sqlite3StrIHash(const char*);
+SQLITE_PRIVATE int sqlite3ResolveExprNames(NameContext*, Expr*);
+SQLITE_PRIVATE int sqlite3ResolveExprListNames(NameContext*, ExprList*);
+SQLITE_PRIVATE void sqlite3ResolveSelectNames(Parse*, Select*, NameContext*);
+SQLITE_PRIVATE int sqlite3ResolveSelfReference(Parse*,Table*,int,Expr*,ExprList*);
+SQLITE_PRIVATE int sqlite3ResolveOrderGroupBy(Parse*, Select*, ExprList*, const char*);
+SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *, Table *, int, int);
+SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *, Token *);
+SQLITE_PRIVATE void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
+SQLITE_PRIVATE void sqlite3AlterDropColumn(Parse*, SrcList*, const Token*);
+SQLITE_PRIVATE const void *sqlite3RenameTokenMap(Parse*, const void*, const Token*);
+SQLITE_PRIVATE void sqlite3RenameTokenRemap(Parse*, const void *pTo, const void *pFrom);
+SQLITE_PRIVATE void sqlite3RenameExprUnmap(Parse*, Expr*);
+SQLITE_PRIVATE void sqlite3RenameExprlistUnmap(Parse*, ExprList*);
+SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(Parse*, u8, CollSeq *, const char*);
+SQLITE_PRIVATE char sqlite3AffinityType(const char*, Column*);
+SQLITE_PRIVATE void sqlite3Analyze(Parse*, Token*, Token*);
+SQLITE_PRIVATE int sqlite3InvokeBusyHandler(BusyHandler*);
+SQLITE_PRIVATE int sqlite3FindDb(sqlite3*, Token*);
+SQLITE_PRIVATE int sqlite3FindDbName(sqlite3 *, const char *);
+SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3*,int iDB);
+SQLITE_PRIVATE void sqlite3DeleteIndexSamples(sqlite3*,Index*);
+SQLITE_PRIVATE void sqlite3DefaultRowEst(Index*);
+SQLITE_PRIVATE void sqlite3RegisterLikeFunctions(sqlite3*, int);
+SQLITE_PRIVATE int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
+SQLITE_PRIVATE void sqlite3SchemaClear(void *);
+SQLITE_PRIVATE Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
+SQLITE_PRIVATE int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoAlloc(sqlite3*,int,int);
+SQLITE_PRIVATE void sqlite3KeyInfoUnref(KeyInfo*);
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoRef(KeyInfo*);
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoOfIndex(Parse*, Index*);
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoFromExprList(Parse*, ExprList*, int, int);
+SQLITE_PRIVATE const char *sqlite3SelectOpName(int);
+SQLITE_PRIVATE int sqlite3HasExplicitNulls(Parse*, ExprList*);
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3KeyInfoIsWriteable(KeyInfo*);
+#endif
+SQLITE_PRIVATE int sqlite3CreateFunc(sqlite3 *, const char *, int, int, void *,
+  void (*)(sqlite3_context*,int,sqlite3_value **),
+  void (*)(sqlite3_context*,int,sqlite3_value **),
+  void (*)(sqlite3_context*),
+  void (*)(sqlite3_context*),
+  void (*)(sqlite3_context*,int,sqlite3_value **),
+  FuncDestructor *pDestructor
+);
+SQLITE_PRIVATE void sqlite3NoopDestructor(void*);
+SQLITE_PRIVATE void *sqlite3OomFault(sqlite3*);
+SQLITE_PRIVATE void sqlite3OomClear(sqlite3*);
+SQLITE_PRIVATE int sqlite3ApiExit(sqlite3 *db, int);
+SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *);
+
+SQLITE_PRIVATE char *sqlite3RCStrRef(char*);
+SQLITE_PRIVATE void sqlite3RCStrUnref(void*);
+SQLITE_PRIVATE char *sqlite3RCStrNew(u64);
+SQLITE_PRIVATE char *sqlite3RCStrResize(char*,u64);
+
+SQLITE_PRIVATE void sqlite3StrAccumInit(StrAccum*, sqlite3*, char*, int, int);
+SQLITE_PRIVATE int sqlite3StrAccumEnlarge(StrAccum*, i64);
+SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum*);
+SQLITE_PRIVATE void sqlite3StrAccumSetError(StrAccum*, u8);
+SQLITE_PRIVATE void sqlite3ResultStrAccum(sqlite3_context*,StrAccum*);
+SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest*,int,int);
+SQLITE_PRIVATE Expr *sqlite3CreateColumnExpr(sqlite3 *, SrcList *, int, int);
+SQLITE_PRIVATE void sqlite3RecordErrorByteOffset(sqlite3*,const char*);
+SQLITE_PRIVATE void sqlite3RecordErrorOffsetOfExpr(sqlite3*,const Expr*);
+
+SQLITE_PRIVATE void sqlite3BackupRestart(sqlite3_backup *);
+SQLITE_PRIVATE void sqlite3BackupUpdate(sqlite3_backup *, Pgno, const u8 *);
+
+#ifndef SQLITE_OMIT_SUBQUERY
+SQLITE_PRIVATE int sqlite3ExprCheckIN(Parse*, Expr*);
+#else
+# define sqlite3ExprCheckIN(x,y) SQLITE_OK
+#endif
+
+#ifdef SQLITE_ENABLE_STAT4
+SQLITE_PRIVATE int sqlite3Stat4ProbeSetValue(
+    Parse*,Index*,UnpackedRecord**,Expr*,int,int,int*);
+SQLITE_PRIVATE int sqlite3Stat4ValueFromExpr(Parse*, Expr*, u8, sqlite3_value**);
+SQLITE_PRIVATE void sqlite3Stat4ProbeFree(UnpackedRecord*);
+SQLITE_PRIVATE int sqlite3Stat4Column(sqlite3*, const void*, int, int, sqlite3_value**);
+SQLITE_PRIVATE char sqlite3IndexColumnAffinity(sqlite3*, Index*, int);
+#endif
+
+/*
+** The interface to the LEMON-generated parser
+*/
+#ifndef SQLITE_AMALGAMATION
+SQLITE_PRIVATE   void *sqlite3ParserAlloc(void*(*)(u64), Parse*);
+SQLITE_PRIVATE   void sqlite3ParserFree(void*, void(*)(void*));
+#endif
+SQLITE_PRIVATE void sqlite3Parser(void*, int, Token);
+SQLITE_PRIVATE int sqlite3ParserFallback(int);
+#ifdef YYTRACKMAXSTACKDEPTH
+SQLITE_PRIVATE   int sqlite3ParserStackPeak(void*);
+#endif
+
+SQLITE_PRIVATE void sqlite3AutoLoadExtensions(sqlite3*);
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+SQLITE_PRIVATE   void sqlite3CloseExtensions(sqlite3*);
+#else
+# define sqlite3CloseExtensions(X)
+#endif
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+SQLITE_PRIVATE   void sqlite3TableLock(Parse *, int, Pgno, u8, const char *);
+#else
+  #define sqlite3TableLock(v,w,x,y,z)
+#endif
+
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE   int sqlite3Utf8To8(unsigned char*);
+#endif
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+#  define sqlite3VtabClear(D,T)
+#  define sqlite3VtabSync(X,Y) SQLITE_OK
+#  define sqlite3VtabRollback(X)
+#  define sqlite3VtabCommit(X)
+#  define sqlite3VtabInSync(db) 0
+#  define sqlite3VtabLock(X)
+#  define sqlite3VtabUnlock(X)
+#  define sqlite3VtabModuleUnref(D,X)
+#  define sqlite3VtabUnlockList(X)
+#  define sqlite3VtabSavepoint(X, Y, Z) SQLITE_OK
+#  define sqlite3GetVTable(X,Y)  ((VTable*)0)
+#else
+SQLITE_PRIVATE    void sqlite3VtabClear(sqlite3 *db, Table*);
+SQLITE_PRIVATE    void sqlite3VtabDisconnect(sqlite3 *db, Table *p);
+SQLITE_PRIVATE    int sqlite3VtabSync(sqlite3 *db, Vdbe*);
+SQLITE_PRIVATE    int sqlite3VtabRollback(sqlite3 *db);
+SQLITE_PRIVATE    int sqlite3VtabCommit(sqlite3 *db);
+SQLITE_PRIVATE    void sqlite3VtabLock(VTable *);
+SQLITE_PRIVATE    void sqlite3VtabUnlock(VTable *);
+SQLITE_PRIVATE    void sqlite3VtabModuleUnref(sqlite3*,Module*);
+SQLITE_PRIVATE    void sqlite3VtabUnlockList(sqlite3*);
+SQLITE_PRIVATE    int sqlite3VtabSavepoint(sqlite3 *, int, int);
+SQLITE_PRIVATE    void sqlite3VtabImportErrmsg(Vdbe*, sqlite3_vtab*);
+SQLITE_PRIVATE    VTable *sqlite3GetVTable(sqlite3*, Table*);
+SQLITE_PRIVATE    Module *sqlite3VtabCreateModule(
+     sqlite3*,
+     const char*,
+     const sqlite3_module*,
+     void*,
+     void(*)(void*)
+   );
+#  define sqlite3VtabInSync(db) ((db)->nVTrans>0 && (db)->aVTrans==0)
+#endif
+SQLITE_PRIVATE int sqlite3ReadOnlyShadowTables(sqlite3 *db);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+SQLITE_PRIVATE   int sqlite3ShadowTableName(sqlite3 *db, const char *zName);
+SQLITE_PRIVATE   int sqlite3IsShadowTableOf(sqlite3*,Table*,const char*);
+SQLITE_PRIVATE   void sqlite3MarkAllShadowTablesOf(sqlite3*, Table*);
+#else
+# define sqlite3ShadowTableName(A,B) 0
+# define sqlite3IsShadowTableOf(A,B,C) 0
+# define sqlite3MarkAllShadowTablesOf(A,B)
+#endif
+SQLITE_PRIVATE int sqlite3VtabEponymousTableInit(Parse*,Module*);
+SQLITE_PRIVATE void sqlite3VtabEponymousTableClear(sqlite3*,Module*);
+SQLITE_PRIVATE void sqlite3VtabMakeWritable(Parse*,Table*);
+SQLITE_PRIVATE void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*, int);
+SQLITE_PRIVATE void sqlite3VtabFinishParse(Parse*, Token*);
+SQLITE_PRIVATE void sqlite3VtabArgInit(Parse*);
+SQLITE_PRIVATE void sqlite3VtabArgExtend(Parse*, Token*);
+SQLITE_PRIVATE int sqlite3VtabCallCreate(sqlite3*, int, const char *, char **);
+SQLITE_PRIVATE int sqlite3VtabCallConnect(Parse*, Table*);
+SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3*, int, const char *);
+SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *, VTable *);
+
+SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
+SQLITE_PRIVATE void sqlite3VtabUsesAllSchemas(Parse*);
+SQLITE_PRIVATE sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context*);
+SQLITE_PRIVATE int sqlite3VdbeParameterIndex(Vdbe*, const char*, int);
+SQLITE_PRIVATE int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
+SQLITE_PRIVATE void sqlite3ParseObjectInit(Parse*,sqlite3*);
+SQLITE_PRIVATE void sqlite3ParseObjectReset(Parse*);
+SQLITE_PRIVATE void *sqlite3ParserAddCleanup(Parse*,void(*)(sqlite3*,void*),void*);
+#ifdef SQLITE_ENABLE_NORMALIZE
+SQLITE_PRIVATE char *sqlite3Normalize(Vdbe*, const char*);
+#endif
+SQLITE_PRIVATE int sqlite3Reprepare(Vdbe*);
+SQLITE_PRIVATE void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
+SQLITE_PRIVATE CollSeq *sqlite3ExprCompareCollSeq(Parse*,const Expr*);
+SQLITE_PRIVATE CollSeq *sqlite3BinaryCompareCollSeq(Parse *, const Expr*, const Expr*);
+SQLITE_PRIVATE int sqlite3TempInMemory(const sqlite3*);
+SQLITE_PRIVATE const char *sqlite3JournalModename(int);
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE   int sqlite3Checkpoint(sqlite3*, int, int, int*, int*);
+SQLITE_PRIVATE   int sqlite3WalDefaultHook(void*,sqlite3*,const char*,int);
+#endif
+#ifndef SQLITE_OMIT_CTE
+SQLITE_PRIVATE   Cte *sqlite3CteNew(Parse*,Token*,ExprList*,Select*,u8);
+SQLITE_PRIVATE   void sqlite3CteDelete(sqlite3*,Cte*);
+SQLITE_PRIVATE   With *sqlite3WithAdd(Parse*,With*,Cte*);
+SQLITE_PRIVATE   void sqlite3WithDelete(sqlite3*,With*);
+SQLITE_PRIVATE   void sqlite3WithDeleteGeneric(sqlite3*,void*);
+SQLITE_PRIVATE   With *sqlite3WithPush(Parse*, With*, u8);
+#else
+# define sqlite3CteNew(P,T,E,S)   ((void*)0)
+# define sqlite3CteDelete(D,C)
+# define sqlite3CteWithAdd(P,W,C) ((void*)0)
+# define sqlite3WithDelete(x,y)
+# define sqlite3WithPush(x,y,z) ((void*)0)
+#endif
+#ifndef SQLITE_OMIT_UPSERT
+SQLITE_PRIVATE   Upsert *sqlite3UpsertNew(sqlite3*,ExprList*,Expr*,ExprList*,Expr*,Upsert*);
+SQLITE_PRIVATE   void sqlite3UpsertDelete(sqlite3*,Upsert*);
+SQLITE_PRIVATE   Upsert *sqlite3UpsertDup(sqlite3*,Upsert*);
+SQLITE_PRIVATE   int sqlite3UpsertAnalyzeTarget(Parse*,SrcList*,Upsert*,Upsert*);
+SQLITE_PRIVATE   void sqlite3UpsertDoUpdate(Parse*,Upsert*,Table*,Index*,int);
+SQLITE_PRIVATE   Upsert *sqlite3UpsertOfIndex(Upsert*,Index*);
+SQLITE_PRIVATE   int sqlite3UpsertNextIsIPK(Upsert*);
+#else
+#define sqlite3UpsertNew(u,v,w,x,y,z) ((Upsert*)0)
+#define sqlite3UpsertDelete(x,y)
+#define sqlite3UpsertDup(x,y)         ((Upsert*)0)
+#define sqlite3UpsertOfIndex(x,y)     ((Upsert*)0)
+#define sqlite3UpsertNextIsIPK(x)     0
+#endif
+
+
+/* Declarations for functions in fkey.c. All of these are replaced by
+** no-op macros if OMIT_FOREIGN_KEY is defined. In this case no foreign
+** key functionality is available. If OMIT_TRIGGER is defined but
+** OMIT_FOREIGN_KEY is not, only some of the functions are no-oped. In
+** this case foreign keys are parsed, but no other functionality is
+** provided (enforcement of FK constraints requires the triggers sub-system).
+*/
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+SQLITE_PRIVATE   void sqlite3FkCheck(Parse*, Table*, int, int, int*, int);
+SQLITE_PRIVATE   void sqlite3FkDropTable(Parse*, SrcList *, Table*);
+SQLITE_PRIVATE   void sqlite3FkActions(Parse*, Table*, ExprList*, int, int*, int);
+SQLITE_PRIVATE   int sqlite3FkRequired(Parse*, Table*, int*, int);
+SQLITE_PRIVATE   u32 sqlite3FkOldmask(Parse*, Table*);
+SQLITE_PRIVATE   FKey *sqlite3FkReferences(Table *);
+SQLITE_PRIVATE   void sqlite3FkClearTriggerCache(sqlite3*,int);
+#else
+  #define sqlite3FkActions(a,b,c,d,e,f)
+  #define sqlite3FkCheck(a,b,c,d,e,f)
+  #define sqlite3FkDropTable(a,b,c)
+  #define sqlite3FkOldmask(a,b)         0
+  #define sqlite3FkRequired(a,b,c,d)    0
+  #define sqlite3FkReferences(a)        0
+  #define sqlite3FkClearTriggerCache(a,b)
+#endif
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+SQLITE_PRIVATE   void sqlite3FkDelete(sqlite3 *, Table*);
+SQLITE_PRIVATE   int sqlite3FkLocateIndex(Parse*,Table*,FKey*,Index**,int**);
+#else
+  #define sqlite3FkDelete(a,b)
+  #define sqlite3FkLocateIndex(a,b,c,d,e)
+#endif
+
+
+/*
+** Available fault injectors.  Should be numbered beginning with 0.
+*/
+#define SQLITE_FAULTINJECTOR_MALLOC     0
+#define SQLITE_FAULTINJECTOR_COUNT      1
+
+/*
+** The interface to the code in fault.c used for identifying "benign"
+** malloc failures. This is only present if SQLITE_UNTESTABLE
+** is not defined.
+*/
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE   void sqlite3BeginBenignMalloc(void);
+SQLITE_PRIVATE   void sqlite3EndBenignMalloc(void);
+#else
+  #define sqlite3BeginBenignMalloc()
+  #define sqlite3EndBenignMalloc()
+#endif
+
+/*
+** Allowed return values from sqlite3FindInIndex()
+*/
+#define IN_INDEX_ROWID        1   /* Search the rowid of the table */
+#define IN_INDEX_EPH          2   /* Search an ephemeral b-tree */
+#define IN_INDEX_INDEX_ASC    3   /* Existing index ASCENDING */
+#define IN_INDEX_INDEX_DESC   4   /* Existing index DESCENDING */
+#define IN_INDEX_NOOP         5   /* No table available. Use comparisons */
+/*
+** Allowed flags for the 3rd parameter to sqlite3FindInIndex().
+*/
+#define IN_INDEX_NOOP_OK     0x0001  /* OK to return IN_INDEX_NOOP */
+#define IN_INDEX_MEMBERSHIP  0x0002  /* IN operator used for membership test */
+#define IN_INDEX_LOOP        0x0004  /* IN operator used as a loop */
+SQLITE_PRIVATE int sqlite3FindInIndex(Parse *, Expr *, u32, int*, int*, int*);
+
+SQLITE_PRIVATE int sqlite3JournalOpen(sqlite3_vfs *, const char *, sqlite3_file *, int, int);
+SQLITE_PRIVATE int sqlite3JournalSize(sqlite3_vfs *);
+#if defined(SQLITE_ENABLE_ATOMIC_WRITE) \
+ || defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+SQLITE_PRIVATE   int sqlite3JournalCreate(sqlite3_file *);
+#endif
+
+SQLITE_PRIVATE int sqlite3JournalIsInMemory(sqlite3_file *p);
+SQLITE_PRIVATE void sqlite3MemJournalOpen(sqlite3_file *);
+
+SQLITE_PRIVATE void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p);
+#if SQLITE_MAX_EXPR_DEPTH>0
+SQLITE_PRIVATE   int sqlite3SelectExprHeight(const Select *);
+SQLITE_PRIVATE   int sqlite3ExprCheckHeight(Parse*, int);
+#else
+  #define sqlite3SelectExprHeight(x) 0
+  #define sqlite3ExprCheckHeight(x,y)
+#endif
+SQLITE_PRIVATE void sqlite3ExprSetErrorOffset(Expr*,int);
+
+SQLITE_PRIVATE u32 sqlite3Get4byte(const u8*);
+SQLITE_PRIVATE void sqlite3Put4byte(u8*, u32);
+
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+SQLITE_PRIVATE   void sqlite3ConnectionBlocked(sqlite3 *, sqlite3 *);
+SQLITE_PRIVATE   void sqlite3ConnectionUnlocked(sqlite3 *db);
+SQLITE_PRIVATE   void sqlite3ConnectionClosed(sqlite3 *db);
+#else
+  #define sqlite3ConnectionBlocked(x,y)
+  #define sqlite3ConnectionUnlocked(x)
+  #define sqlite3ConnectionClosed(x)
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3ParserTrace(FILE*, char *);
+#endif
+#if defined(YYCOVERAGE)
+SQLITE_PRIVATE   int sqlite3ParserCoverage(FILE*);
+#endif
+
+/*
+** If the SQLITE_ENABLE IOTRACE exists then the global variable
+** sqlite3IoTrace is a pointer to a printf-like routine used to
+** print I/O tracing messages.
+*/
+#ifdef SQLITE_ENABLE_IOTRACE
+# define IOTRACE(A)  if( sqlite3IoTrace ){ sqlite3IoTrace A; }
+SQLITE_PRIVATE   void sqlite3VdbeIOTraceSql(Vdbe*);
+SQLITE_API SQLITE_EXTERN void (SQLITE_CDECL *sqlite3IoTrace)(const char*,...);
+#else
+# define IOTRACE(A)
+# define sqlite3VdbeIOTraceSql(X)
+#endif
+
+/*
+** These routines are available for the mem2.c debugging memory allocator
+** only.  They are used to verify that different "types" of memory
+** allocations are properly tracked by the system.
+**
+** sqlite3MemdebugSetType() sets the "type" of an allocation to one of
+** the MEMTYPE_* macros defined below.  The type must be a bitmask with
+** a single bit set.
+**
+** sqlite3MemdebugHasType() returns true if any of the bits in its second
+** argument match the type set by the previous sqlite3MemdebugSetType().
+** sqlite3MemdebugHasType() is intended for use inside assert() statements.
+**
+** sqlite3MemdebugNoType() returns true if none of the bits in its second
+** argument match the type set by the previous sqlite3MemdebugSetType().
+**
+** Perhaps the most important point is the difference between MEMTYPE_HEAP
+** and MEMTYPE_LOOKASIDE.  If an allocation is MEMTYPE_LOOKASIDE, that means
+** it might have been allocated by lookaside, except the allocation was
+** too large or lookaside was already full.  It is important to verify
+** that allocations that might have been satisfied by lookaside are not
+** passed back to non-lookaside free() routines.  Asserts such as the
+** example above are placed on the non-lookaside free() routines to verify
+** this constraint.
+**
+** All of this is no-op for a production build.  It only comes into
+** play when the SQLITE_MEMDEBUG compile-time option is used.
+*/
+#ifdef SQLITE_MEMDEBUG
+SQLITE_PRIVATE   void sqlite3MemdebugSetType(void*,u8);
+SQLITE_PRIVATE   int sqlite3MemdebugHasType(const void*,u8);
+SQLITE_PRIVATE   int sqlite3MemdebugNoType(const void*,u8);
+#else
+# define sqlite3MemdebugSetType(X,Y)  /* no-op */
+# define sqlite3MemdebugHasType(X,Y)  1
+# define sqlite3MemdebugNoType(X,Y)   1
+#endif
+#define MEMTYPE_HEAP       0x01  /* General heap allocations */
+#define MEMTYPE_LOOKASIDE  0x02  /* Heap that might have been lookaside */
+#define MEMTYPE_PCACHE     0x04  /* Page cache allocations */
+
+/*
+** Threading interface
+*/
+#if SQLITE_MAX_WORKER_THREADS>0
+SQLITE_PRIVATE int sqlite3ThreadCreate(SQLiteThread**,void*(*)(void*),void*);
+SQLITE_PRIVATE int sqlite3ThreadJoin(SQLiteThread*, void**);
+#endif
+
+#if defined(SQLITE_ENABLE_DBPAGE_VTAB) || defined(SQLITE_TEST)
+SQLITE_PRIVATE int sqlite3DbpageRegister(sqlite3*);
+#endif
+#if defined(SQLITE_ENABLE_DBSTAT_VTAB) || defined(SQLITE_TEST)
+SQLITE_PRIVATE int sqlite3DbstatRegister(sqlite3*);
+#endif
+
+SQLITE_PRIVATE int sqlite3ExprVectorSize(const Expr *pExpr);
+SQLITE_PRIVATE int sqlite3ExprIsVector(const Expr *pExpr);
+SQLITE_PRIVATE Expr *sqlite3VectorFieldSubexpr(Expr*, int);
+SQLITE_PRIVATE Expr *sqlite3ExprForVectorField(Parse*,Expr*,int,int);
+SQLITE_PRIVATE void sqlite3VectorErrorMsg(Parse*, Expr*);
+
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+SQLITE_PRIVATE const char **sqlite3CompileOptions(int *pnOpt);
+#endif
+
+#if SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL)
+SQLITE_PRIVATE int sqlite3KvvfsInit(void);
+#endif
+
+#if defined(VDBE_PROFILE) \
+ || defined(SQLITE_PERFORMANCE_TRACE) \
+ || defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+SQLITE_PRIVATE sqlite3_uint64 sqlite3Hwtime(void);
+#endif
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+# define IS_STMT_SCANSTATUS(db) (db->flags & SQLITE_StmtScanStatus)
+#else
+# define IS_STMT_SCANSTATUS(db) 0
+#endif
+
+#endif /* SQLITEINT_H */
+
+/************** End of sqliteInt.h *******************************************/
+/************** Begin file os_common.h ***************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains macros and a little bit of code that is common to
+** all of the platform-specific files (os_*.c) and is #included into those
+** files.
+**
+** This file should be #included by the os_*.c files only.  It is not a
+** general purpose header file.
+*/
+#ifndef _OS_COMMON_H_
+#define _OS_COMMON_H_
+
+/*
+** At least two bugs have slipped in because we changed the MEMORY_DEBUG
+** macro to SQLITE_DEBUG and some older makefiles have not yet made the
+** switch.  The following code should catch this problem at compile-time.
+*/
+#ifdef MEMORY_DEBUG
+# error "The MEMORY_DEBUG macro is obsolete.  Use SQLITE_DEBUG instead."
+#endif
+
+/*
+** Macros for performance tracing.  Normally turned off.  Only works
+** on i486 hardware.
+*/
+#ifdef SQLITE_PERFORMANCE_TRACE
+
+static sqlite_uint64 g_start;
+static sqlite_uint64 g_elapsed;
+#define TIMER_START       g_start=sqlite3Hwtime()
+#define TIMER_END         g_elapsed=sqlite3Hwtime()-g_start
+#define TIMER_ELAPSED     g_elapsed
+#else
+#define TIMER_START
+#define TIMER_END
+#define TIMER_ELAPSED     ((sqlite_uint64)0)
+#endif
+
+/*
+** If we compile with the SQLITE_TEST macro set, then the following block
+** of code will give us the ability to simulate a disk I/O error.  This
+** is used for testing the I/O recovery logic.
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API extern int sqlite3_io_error_hit;
+SQLITE_API extern int sqlite3_io_error_hardhit;
+SQLITE_API extern int sqlite3_io_error_pending;
+SQLITE_API extern int sqlite3_io_error_persist;
+SQLITE_API extern int sqlite3_io_error_benign;
+SQLITE_API extern int sqlite3_diskfull_pending;
+SQLITE_API extern int sqlite3_diskfull;
+#define SimulateIOErrorBenign(X) sqlite3_io_error_benign=(X)
+#define SimulateIOError(CODE)  \
+  if( (sqlite3_io_error_persist && sqlite3_io_error_hit) \
+       || sqlite3_io_error_pending-- == 1 )  \
+              { local_ioerr(); CODE; }
+static void local_ioerr(){
+  IOTRACE(("IOERR\n"));
+  sqlite3_io_error_hit++;
+  if( !sqlite3_io_error_benign ) sqlite3_io_error_hardhit++;
+}
+#define SimulateDiskfullError(CODE) \
+   if( sqlite3_diskfull_pending ){ \
+     if( sqlite3_diskfull_pending == 1 ){ \
+       local_ioerr(); \
+       sqlite3_diskfull = 1; \
+       sqlite3_io_error_hit = 1; \
+       CODE; \
+     }else{ \
+       sqlite3_diskfull_pending--; \
+     } \
+   }
+#else
+#define SimulateIOErrorBenign(X)
+#define SimulateIOError(A)
+#define SimulateDiskfullError(A)
+#endif /* defined(SQLITE_TEST) */
+
+/*
+** When testing, keep a count of the number of open files.
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API extern int sqlite3_open_file_count;
+#define OpenCounter(X)  sqlite3_open_file_count+=(X)
+#else
+#define OpenCounter(X)
+#endif /* defined(SQLITE_TEST) */
+
+#endif /* !defined(_OS_COMMON_H_) */
+
+/************** End of os_common.h *******************************************/
+/************** Begin file ctime.c *******************************************/
+/* DO NOT EDIT!
+** This file is automatically generated by the script in the canonical
+** SQLite source tree at tool/mkctimec.tcl.
+**
+** To modify this header, edit any of the various lists in that script
+** which specify categories of generated conditionals in this file.
+*/
+
+/*
+** 2010 February 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements routines used to report what compile-time options
+** SQLite was built with.
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS /* IMP: R-16824-07538 */
+
+/*
+** Include the configuration header output by 'configure' if we're using the
+** autoconf-based build
+*/
+#if defined(_HAVE_SQLITE_CONFIG_H) && !defined(SQLITECONFIG_H)
+/* #include "sqlite_cfg.h" */
+#define SQLITECONFIG_H 1
+#endif
+
+/* These macros are provided to "stringify" the value of the define
+** for those options in which the value is meaningful. */
+#define CTIMEOPT_VAL_(opt) #opt
+#define CTIMEOPT_VAL(opt) CTIMEOPT_VAL_(opt)
+
+/* Like CTIMEOPT_VAL, but especially for SQLITE_DEFAULT_LOOKASIDE. This
+** option requires a separate macro because legal values contain a single
+** comma. e.g. (-DSQLITE_DEFAULT_LOOKASIDE="100,100") */
+#define CTIMEOPT_VAL2_(opt1,opt2) #opt1 "," #opt2
+#define CTIMEOPT_VAL2(opt) CTIMEOPT_VAL2_(opt)
+/* #include "sqliteInt.h" */
+
+/*
+** An array of names of all compile-time options.  This array should
+** be sorted A-Z.
+**
+** This array looks large, but in a typical installation actually uses
+** only a handful of compile-time options, so most times this array is usually
+** rather short and uses little memory space.
+*/
+static const char * const sqlite3azCompileOpt[] = {
+
+#ifdef SQLITE_32BIT_ROWID
+  "32BIT_ROWID",
+#endif
+#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
+  "4_BYTE_ALIGNED_MALLOC",
+#endif
+#ifdef SQLITE_ALLOW_COVERING_INDEX_SCAN
+# if SQLITE_ALLOW_COVERING_INDEX_SCAN != 1
+  "ALLOW_COVERING_INDEX_SCAN=" CTIMEOPT_VAL(SQLITE_ALLOW_COVERING_INDEX_SCAN),
+# endif
+#endif
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  "ALLOW_ROWID_IN_VIEW",
+#endif
+#ifdef SQLITE_ALLOW_URI_AUTHORITY
+  "ALLOW_URI_AUTHORITY",
+#endif
+#ifdef SQLITE_ATOMIC_INTRINSICS
+  "ATOMIC_INTRINSICS=" CTIMEOPT_VAL(SQLITE_ATOMIC_INTRINSICS),
+#endif
+#ifdef SQLITE_BITMASK_TYPE
+  "BITMASK_TYPE=" CTIMEOPT_VAL(SQLITE_BITMASK_TYPE),
+#endif
+#ifdef SQLITE_BUG_COMPATIBLE_20160819
+  "BUG_COMPATIBLE_20160819",
+#endif
+#ifdef SQLITE_CASE_SENSITIVE_LIKE
+  "CASE_SENSITIVE_LIKE",
+#endif
+#ifdef SQLITE_CHECK_PAGES
+  "CHECK_PAGES",
+#endif
+#if defined(__clang__) && defined(__clang_major__)
+  "COMPILER=clang-" CTIMEOPT_VAL(__clang_major__) "."
+                    CTIMEOPT_VAL(__clang_minor__) "."
+                    CTIMEOPT_VAL(__clang_patchlevel__),
+#elif defined(_MSC_VER)
+  "COMPILER=msvc-" CTIMEOPT_VAL(_MSC_VER),
+#elif defined(__GNUC__) && defined(__VERSION__)
+  "COMPILER=gcc-" __VERSION__,
+#endif
+#ifdef SQLITE_COVERAGE_TEST
+  "COVERAGE_TEST",
+#endif
+#ifdef SQLITE_DEBUG
+  "DEBUG",
+#endif
+#ifdef SQLITE_DEFAULT_AUTOMATIC_INDEX
+  "DEFAULT_AUTOMATIC_INDEX",
+#endif
+#ifdef SQLITE_DEFAULT_AUTOVACUUM
+  "DEFAULT_AUTOVACUUM",
+#endif
+#ifdef SQLITE_DEFAULT_CACHE_SIZE
+  "DEFAULT_CACHE_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_CACHE_SIZE),
+#endif
+#ifdef SQLITE_DEFAULT_CKPTFULLFSYNC
+  "DEFAULT_CKPTFULLFSYNC",
+#endif
+#ifdef SQLITE_DEFAULT_FILE_FORMAT
+  "DEFAULT_FILE_FORMAT=" CTIMEOPT_VAL(SQLITE_DEFAULT_FILE_FORMAT),
+#endif
+#ifdef SQLITE_DEFAULT_FILE_PERMISSIONS
+  "DEFAULT_FILE_PERMISSIONS=" CTIMEOPT_VAL(SQLITE_DEFAULT_FILE_PERMISSIONS),
+#endif
+#ifdef SQLITE_DEFAULT_FOREIGN_KEYS
+  "DEFAULT_FOREIGN_KEYS",
+#endif
+#ifdef SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT
+  "DEFAULT_JOURNAL_SIZE_LIMIT=" CTIMEOPT_VAL(SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT),
+#endif
+#ifdef SQLITE_DEFAULT_LOCKING_MODE
+  "DEFAULT_LOCKING_MODE=" CTIMEOPT_VAL(SQLITE_DEFAULT_LOCKING_MODE),
+#endif
+#ifdef SQLITE_DEFAULT_LOOKASIDE
+  "DEFAULT_LOOKASIDE=" CTIMEOPT_VAL2(SQLITE_DEFAULT_LOOKASIDE),
+#endif
+#ifdef SQLITE_DEFAULT_MEMSTATUS
+# if SQLITE_DEFAULT_MEMSTATUS != 1
+  "DEFAULT_MEMSTATUS=" CTIMEOPT_VAL(SQLITE_DEFAULT_MEMSTATUS),
+# endif
+#endif
+#ifdef SQLITE_DEFAULT_MMAP_SIZE
+  "DEFAULT_MMAP_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_MMAP_SIZE),
+#endif
+#ifdef SQLITE_DEFAULT_PAGE_SIZE
+  "DEFAULT_PAGE_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_PAGE_SIZE),
+#endif
+#ifdef SQLITE_DEFAULT_PCACHE_INITSZ
+  "DEFAULT_PCACHE_INITSZ=" CTIMEOPT_VAL(SQLITE_DEFAULT_PCACHE_INITSZ),
+#endif
+#ifdef SQLITE_DEFAULT_PROXYDIR_PERMISSIONS
+  "DEFAULT_PROXYDIR_PERMISSIONS=" CTIMEOPT_VAL(SQLITE_DEFAULT_PROXYDIR_PERMISSIONS),
+#endif
+#ifdef SQLITE_DEFAULT_RECURSIVE_TRIGGERS
+  "DEFAULT_RECURSIVE_TRIGGERS",
+#endif
+#ifdef SQLITE_DEFAULT_ROWEST
+  "DEFAULT_ROWEST=" CTIMEOPT_VAL(SQLITE_DEFAULT_ROWEST),
+#endif
+#ifdef SQLITE_DEFAULT_SECTOR_SIZE
+  "DEFAULT_SECTOR_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_SECTOR_SIZE),
+#endif
+#ifdef SQLITE_DEFAULT_SYNCHRONOUS
+  "DEFAULT_SYNCHRONOUS=" CTIMEOPT_VAL(SQLITE_DEFAULT_SYNCHRONOUS),
+#endif
+#ifdef SQLITE_DEFAULT_WAL_AUTOCHECKPOINT
+  "DEFAULT_WAL_AUTOCHECKPOINT=" CTIMEOPT_VAL(SQLITE_DEFAULT_WAL_AUTOCHECKPOINT),
+#endif
+#ifdef SQLITE_DEFAULT_WAL_SYNCHRONOUS
+  "DEFAULT_WAL_SYNCHRONOUS=" CTIMEOPT_VAL(SQLITE_DEFAULT_WAL_SYNCHRONOUS),
+#endif
+#ifdef SQLITE_DEFAULT_WORKER_THREADS
+  "DEFAULT_WORKER_THREADS=" CTIMEOPT_VAL(SQLITE_DEFAULT_WORKER_THREADS),
+#endif
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+  "DIRECT_OVERFLOW_READ",
+#endif
+#ifdef SQLITE_DISABLE_DIRSYNC
+  "DISABLE_DIRSYNC",
+#endif
+#ifdef SQLITE_DISABLE_FTS3_UNICODE
+  "DISABLE_FTS3_UNICODE",
+#endif
+#ifdef SQLITE_DISABLE_FTS4_DEFERRED
+  "DISABLE_FTS4_DEFERRED",
+#endif
+#ifdef SQLITE_DISABLE_INTRINSIC
+  "DISABLE_INTRINSIC",
+#endif
+#ifdef SQLITE_DISABLE_LFS
+  "DISABLE_LFS",
+#endif
+#ifdef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
+  "DISABLE_PAGECACHE_OVERFLOW_STATS",
+#endif
+#ifdef SQLITE_DISABLE_SKIPAHEAD_DISTINCT
+  "DISABLE_SKIPAHEAD_DISTINCT",
+#endif
+#ifdef SQLITE_DQS
+  "DQS=" CTIMEOPT_VAL(SQLITE_DQS),
+#endif
+#ifdef SQLITE_ENABLE_8_3_NAMES
+  "ENABLE_8_3_NAMES=" CTIMEOPT_VAL(SQLITE_ENABLE_8_3_NAMES),
+#endif
+#ifdef SQLITE_ENABLE_API_ARMOR
+  "ENABLE_API_ARMOR",
+#endif
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+  "ENABLE_ATOMIC_WRITE",
+#endif
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+  "ENABLE_BATCH_ATOMIC_WRITE",
+#endif
+#ifdef SQLITE_ENABLE_BYTECODE_VTAB
+  "ENABLE_BYTECODE_VTAB",
+#endif
+#ifdef SQLITE_ENABLE_CEROD
+  "ENABLE_CEROD=" CTIMEOPT_VAL(SQLITE_ENABLE_CEROD),
+#endif
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+  "ENABLE_COLUMN_METADATA",
+#endif
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+  "ENABLE_COLUMN_USED_MASK",
+#endif
+#ifdef SQLITE_ENABLE_COSTMULT
+  "ENABLE_COSTMULT",
+#endif
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+  "ENABLE_CURSOR_HINTS",
+#endif
+#ifdef SQLITE_ENABLE_DBPAGE_VTAB
+  "ENABLE_DBPAGE_VTAB",
+#endif
+#ifdef SQLITE_ENABLE_DBSTAT_VTAB
+  "ENABLE_DBSTAT_VTAB",
+#endif
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+  "ENABLE_EXPENSIVE_ASSERT",
+#endif
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  "ENABLE_EXPLAIN_COMMENTS",
+#endif
+#ifdef SQLITE_ENABLE_FTS3
+  "ENABLE_FTS3",
+#endif
+#ifdef SQLITE_ENABLE_FTS3_PARENTHESIS
+  "ENABLE_FTS3_PARENTHESIS",
+#endif
+#ifdef SQLITE_ENABLE_FTS3_TOKENIZER
+  "ENABLE_FTS3_TOKENIZER",
+#endif
+#ifdef SQLITE_ENABLE_FTS4
+  "ENABLE_FTS4",
+#endif
+#ifdef SQLITE_ENABLE_FTS5
+  "ENABLE_FTS5",
+#endif
+#ifdef SQLITE_ENABLE_GEOPOLY
+  "ENABLE_GEOPOLY",
+#endif
+#ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
+  "ENABLE_HIDDEN_COLUMNS",
+#endif
+#ifdef SQLITE_ENABLE_ICU
+  "ENABLE_ICU",
+#endif
+#ifdef SQLITE_ENABLE_IOTRACE
+  "ENABLE_IOTRACE",
+#endif
+#ifdef SQLITE_ENABLE_LOAD_EXTENSION
+  "ENABLE_LOAD_EXTENSION",
+#endif
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+  "ENABLE_LOCKING_STYLE=" CTIMEOPT_VAL(SQLITE_ENABLE_LOCKING_STYLE),
+#endif
+#ifdef SQLITE_ENABLE_MATH_FUNCTIONS
+  "ENABLE_MATH_FUNCTIONS",
+#endif
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  "ENABLE_MEMORY_MANAGEMENT",
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS3
+  "ENABLE_MEMSYS3",
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS5
+  "ENABLE_MEMSYS5",
+#endif
+#ifdef SQLITE_ENABLE_MULTIPLEX
+  "ENABLE_MULTIPLEX",
+#endif
+#ifdef SQLITE_ENABLE_NORMALIZE
+  "ENABLE_NORMALIZE",
+#endif
+#ifdef SQLITE_ENABLE_NULL_TRIM
+  "ENABLE_NULL_TRIM",
+#endif
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+  "ENABLE_OFFSET_SQL_FUNC",
+#endif
+#ifdef SQLITE_ENABLE_ORDERED_SET_AGGREGATES
+  "ENABLE_ORDERED_SET_AGGREGATES",
+#endif
+#ifdef SQLITE_ENABLE_OVERSIZE_CELL_CHECK
+  "ENABLE_OVERSIZE_CELL_CHECK",
+#endif
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  "ENABLE_PREUPDATE_HOOK",
+#endif
+#ifdef SQLITE_ENABLE_QPSG
+  "ENABLE_QPSG",
+#endif
+#ifdef SQLITE_ENABLE_RBU
+  "ENABLE_RBU",
+#endif
+#ifdef SQLITE_ENABLE_RTREE
+  "ENABLE_RTREE",
+#endif
+#ifdef SQLITE_ENABLE_SESSION
+  "ENABLE_SESSION",
+#endif
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  "ENABLE_SNAPSHOT",
+#endif
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  "ENABLE_SORTER_REFERENCES",
+#endif
+#ifdef SQLITE_ENABLE_SQLLOG
+  "ENABLE_SQLLOG",
+#endif
+#ifdef SQLITE_ENABLE_STAT4
+  "ENABLE_STAT4",
+#endif
+#ifdef SQLITE_ENABLE_STMTVTAB
+  "ENABLE_STMTVTAB",
+#endif
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  "ENABLE_STMT_SCANSTATUS",
+#endif
+#ifdef SQLITE_ENABLE_TREETRACE
+  "ENABLE_TREETRACE",
+#endif
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+  "ENABLE_UNKNOWN_SQL_FUNCTION",
+#endif
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+  "ENABLE_UNLOCK_NOTIFY",
+#endif
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  "ENABLE_UPDATE_DELETE_LIMIT",
+#endif
+#ifdef SQLITE_ENABLE_URI_00_ERROR
+  "ENABLE_URI_00_ERROR",
+#endif
+#ifdef SQLITE_ENABLE_VFSTRACE
+  "ENABLE_VFSTRACE",
+#endif
+#ifdef SQLITE_ENABLE_WHERETRACE
+  "ENABLE_WHERETRACE",
+#endif
+#ifdef SQLITE_ENABLE_ZIPVFS
+  "ENABLE_ZIPVFS",
+#endif
+#ifdef SQLITE_EXPLAIN_ESTIMATED_ROWS
+  "EXPLAIN_ESTIMATED_ROWS",
+#endif
+#ifdef SQLITE_EXTRA_AUTOEXT
+  "EXTRA_AUTOEXT=" CTIMEOPT_VAL(SQLITE_EXTRA_AUTOEXT),
+#endif
+#ifdef SQLITE_EXTRA_IFNULLROW
+  "EXTRA_IFNULLROW",
+#endif
+#ifdef SQLITE_EXTRA_INIT
+  "EXTRA_INIT=" CTIMEOPT_VAL(SQLITE_EXTRA_INIT),
+#endif
+#ifdef SQLITE_EXTRA_SHUTDOWN
+  "EXTRA_SHUTDOWN=" CTIMEOPT_VAL(SQLITE_EXTRA_SHUTDOWN),
+#endif
+#ifdef SQLITE_FTS3_MAX_EXPR_DEPTH
+  "FTS3_MAX_EXPR_DEPTH=" CTIMEOPT_VAL(SQLITE_FTS3_MAX_EXPR_DEPTH),
+#endif
+#ifdef SQLITE_FTS5_ENABLE_TEST_MI
+  "FTS5_ENABLE_TEST_MI",
+#endif
+#ifdef SQLITE_FTS5_NO_WITHOUT_ROWID
+  "FTS5_NO_WITHOUT_ROWID",
+#endif
+#if HAVE_ISNAN || SQLITE_HAVE_ISNAN
+  "HAVE_ISNAN",
+#endif
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+# if SQLITE_HOMEGROWN_RECURSIVE_MUTEX != 1
+  "HOMEGROWN_RECURSIVE_MUTEX=" CTIMEOPT_VAL(SQLITE_HOMEGROWN_RECURSIVE_MUTEX),
+# endif
+#endif
+#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS
+  "IGNORE_AFP_LOCK_ERRORS",
+#endif
+#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
+  "IGNORE_FLOCK_LOCK_ERRORS",
+#endif
+#ifdef SQLITE_INLINE_MEMCPY
+  "INLINE_MEMCPY",
+#endif
+#ifdef SQLITE_INT64_TYPE
+  "INT64_TYPE",
+#endif
+#ifdef SQLITE_INTEGRITY_CHECK_ERROR_MAX
+  "INTEGRITY_CHECK_ERROR_MAX=" CTIMEOPT_VAL(SQLITE_INTEGRITY_CHECK_ERROR_MAX),
+#endif
+#ifdef SQLITE_LEGACY_JSON_VALID
+  "LEGACY_JSON_VALID",
+#endif
+#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+  "LIKE_DOESNT_MATCH_BLOBS",
+#endif
+#ifdef SQLITE_LOCK_TRACE
+  "LOCK_TRACE",
+#endif
+#ifdef SQLITE_LOG_CACHE_SPILL
+  "LOG_CACHE_SPILL",
+#endif
+#ifdef SQLITE_MALLOC_SOFT_LIMIT
+  "MALLOC_SOFT_LIMIT=" CTIMEOPT_VAL(SQLITE_MALLOC_SOFT_LIMIT),
+#endif
+#ifdef SQLITE_MAX_ATTACHED
+  "MAX_ATTACHED=" CTIMEOPT_VAL(SQLITE_MAX_ATTACHED),
+#endif
+#ifdef SQLITE_MAX_COLUMN
+  "MAX_COLUMN=" CTIMEOPT_VAL(SQLITE_MAX_COLUMN),
+#endif
+#ifdef SQLITE_MAX_COMPOUND_SELECT
+  "MAX_COMPOUND_SELECT=" CTIMEOPT_VAL(SQLITE_MAX_COMPOUND_SELECT),
+#endif
+#ifdef SQLITE_MAX_DEFAULT_PAGE_SIZE
+  "MAX_DEFAULT_PAGE_SIZE=" CTIMEOPT_VAL(SQLITE_MAX_DEFAULT_PAGE_SIZE),
+#endif
+#ifdef SQLITE_MAX_EXPR_DEPTH
+  "MAX_EXPR_DEPTH=" CTIMEOPT_VAL(SQLITE_MAX_EXPR_DEPTH),
+#endif
+#ifdef SQLITE_MAX_FUNCTION_ARG
+  "MAX_FUNCTION_ARG=" CTIMEOPT_VAL(SQLITE_MAX_FUNCTION_ARG),
+#endif
+#ifdef SQLITE_MAX_LENGTH
+  "MAX_LENGTH=" CTIMEOPT_VAL(SQLITE_MAX_LENGTH),
+#endif
+#ifdef SQLITE_MAX_LIKE_PATTERN_LENGTH
+  "MAX_LIKE_PATTERN_LENGTH=" CTIMEOPT_VAL(SQLITE_MAX_LIKE_PATTERN_LENGTH),
+#endif
+#ifdef SQLITE_MAX_MEMORY
+  "MAX_MEMORY=" CTIMEOPT_VAL(SQLITE_MAX_MEMORY),
+#endif
+#ifdef SQLITE_MAX_MMAP_SIZE
+  "MAX_MMAP_SIZE=" CTIMEOPT_VAL(SQLITE_MAX_MMAP_SIZE),
+#endif
+#ifdef SQLITE_MAX_MMAP_SIZE_
+  "MAX_MMAP_SIZE_=" CTIMEOPT_VAL(SQLITE_MAX_MMAP_SIZE_),
+#endif
+#ifdef SQLITE_MAX_PAGE_COUNT
+  "MAX_PAGE_COUNT=" CTIMEOPT_VAL(SQLITE_MAX_PAGE_COUNT),
+#endif
+#ifdef SQLITE_MAX_PAGE_SIZE
+  "MAX_PAGE_SIZE=" CTIMEOPT_VAL(SQLITE_MAX_PAGE_SIZE),
+#endif
+#ifdef SQLITE_MAX_SCHEMA_RETRY
+  "MAX_SCHEMA_RETRY=" CTIMEOPT_VAL(SQLITE_MAX_SCHEMA_RETRY),
+#endif
+#ifdef SQLITE_MAX_SQL_LENGTH
+  "MAX_SQL_LENGTH=" CTIMEOPT_VAL(SQLITE_MAX_SQL_LENGTH),
+#endif
+#ifdef SQLITE_MAX_TRIGGER_DEPTH
+  "MAX_TRIGGER_DEPTH=" CTIMEOPT_VAL(SQLITE_MAX_TRIGGER_DEPTH),
+#endif
+#ifdef SQLITE_MAX_VARIABLE_NUMBER
+  "MAX_VARIABLE_NUMBER=" CTIMEOPT_VAL(SQLITE_MAX_VARIABLE_NUMBER),
+#endif
+#ifdef SQLITE_MAX_VDBE_OP
+  "MAX_VDBE_OP=" CTIMEOPT_VAL(SQLITE_MAX_VDBE_OP),
+#endif
+#ifdef SQLITE_MAX_WORKER_THREADS
+  "MAX_WORKER_THREADS=" CTIMEOPT_VAL(SQLITE_MAX_WORKER_THREADS),
+#endif
+#ifdef SQLITE_MEMDEBUG
+  "MEMDEBUG",
+#endif
+#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+  "MIXED_ENDIAN_64BIT_FLOAT",
+#endif
+#ifdef SQLITE_MMAP_READWRITE
+  "MMAP_READWRITE",
+#endif
+#ifdef SQLITE_MUTEX_NOOP
+  "MUTEX_NOOP",
+#endif
+#ifdef SQLITE_MUTEX_OMIT
+  "MUTEX_OMIT",
+#endif
+#ifdef SQLITE_MUTEX_PTHREADS
+  "MUTEX_PTHREADS",
+#endif
+#ifdef SQLITE_MUTEX_W32
+  "MUTEX_W32",
+#endif
+#ifdef SQLITE_NEED_ERR_NAME
+  "NEED_ERR_NAME",
+#endif
+#ifdef SQLITE_NO_SYNC
+  "NO_SYNC",
+#endif
+#ifdef SQLITE_OMIT_ALTERTABLE
+  "OMIT_ALTERTABLE",
+#endif
+#ifdef SQLITE_OMIT_ANALYZE
+  "OMIT_ANALYZE",
+#endif
+#ifdef SQLITE_OMIT_ATTACH
+  "OMIT_ATTACH",
+#endif
+#ifdef SQLITE_OMIT_AUTHORIZATION
+  "OMIT_AUTHORIZATION",
+#endif
+#ifdef SQLITE_OMIT_AUTOINCREMENT
+  "OMIT_AUTOINCREMENT",
+#endif
+#ifdef SQLITE_OMIT_AUTOINIT
+  "OMIT_AUTOINIT",
+#endif
+#ifdef SQLITE_OMIT_AUTOMATIC_INDEX
+  "OMIT_AUTOMATIC_INDEX",
+#endif
+#ifdef SQLITE_OMIT_AUTORESET
+  "OMIT_AUTORESET",
+#endif
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  "OMIT_AUTOVACUUM",
+#endif
+#ifdef SQLITE_OMIT_BETWEEN_OPTIMIZATION
+  "OMIT_BETWEEN_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_BLOB_LITERAL
+  "OMIT_BLOB_LITERAL",
+#endif
+#ifdef SQLITE_OMIT_CAST
+  "OMIT_CAST",
+#endif
+#ifdef SQLITE_OMIT_CHECK
+  "OMIT_CHECK",
+#endif
+#ifdef SQLITE_OMIT_COMPLETE
+  "OMIT_COMPLETE",
+#endif
+#ifdef SQLITE_OMIT_COMPOUND_SELECT
+  "OMIT_COMPOUND_SELECT",
+#endif
+#ifdef SQLITE_OMIT_CONFLICT_CLAUSE
+  "OMIT_CONFLICT_CLAUSE",
+#endif
+#ifdef SQLITE_OMIT_CTE
+  "OMIT_CTE",
+#endif
+#if defined(SQLITE_OMIT_DATETIME_FUNCS) || defined(SQLITE_OMIT_FLOATING_POINT)
+  "OMIT_DATETIME_FUNCS",
+#endif
+#ifdef SQLITE_OMIT_DECLTYPE
+  "OMIT_DECLTYPE",
+#endif
+#ifdef SQLITE_OMIT_DEPRECATED
+  "OMIT_DEPRECATED",
+#endif
+#ifdef SQLITE_OMIT_DESERIALIZE
+  "OMIT_DESERIALIZE",
+#endif
+#ifdef SQLITE_OMIT_DISKIO
+  "OMIT_DISKIO",
+#endif
+#ifdef SQLITE_OMIT_EXPLAIN
+  "OMIT_EXPLAIN",
+#endif
+#ifdef SQLITE_OMIT_FLAG_PRAGMAS
+  "OMIT_FLAG_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_FLOATING_POINT
+  "OMIT_FLOATING_POINT",
+#endif
+#ifdef SQLITE_OMIT_FOREIGN_KEY
+  "OMIT_FOREIGN_KEY",
+#endif
+#ifdef SQLITE_OMIT_GET_TABLE
+  "OMIT_GET_TABLE",
+#endif
+#ifdef SQLITE_OMIT_HEX_INTEGER
+  "OMIT_HEX_INTEGER",
+#endif
+#ifdef SQLITE_OMIT_INCRBLOB
+  "OMIT_INCRBLOB",
+#endif
+#ifdef SQLITE_OMIT_INTEGRITY_CHECK
+  "OMIT_INTEGRITY_CHECK",
+#endif
+#ifdef SQLITE_OMIT_INTROSPECTION_PRAGMAS
+  "OMIT_INTROSPECTION_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_JSON
+  "OMIT_JSON",
+#endif
+#ifdef SQLITE_OMIT_LIKE_OPTIMIZATION
+  "OMIT_LIKE_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_LOAD_EXTENSION
+  "OMIT_LOAD_EXTENSION",
+#endif
+#ifdef SQLITE_OMIT_LOCALTIME
+  "OMIT_LOCALTIME",
+#endif
+#ifdef SQLITE_OMIT_LOOKASIDE
+  "OMIT_LOOKASIDE",
+#endif
+#ifdef SQLITE_OMIT_MEMORYDB
+  "OMIT_MEMORYDB",
+#endif
+#ifdef SQLITE_OMIT_OR_OPTIMIZATION
+  "OMIT_OR_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_PAGER_PRAGMAS
+  "OMIT_PAGER_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_PARSER_TRACE
+  "OMIT_PARSER_TRACE",
+#endif
+#ifdef SQLITE_OMIT_POPEN
+  "OMIT_POPEN",
+#endif
+#ifdef SQLITE_OMIT_PRAGMA
+  "OMIT_PRAGMA",
+#endif
+#ifdef SQLITE_OMIT_PROGRESS_CALLBACK
+  "OMIT_PROGRESS_CALLBACK",
+#endif
+#ifdef SQLITE_OMIT_QUICKBALANCE
+  "OMIT_QUICKBALANCE",
+#endif
+#ifdef SQLITE_OMIT_REINDEX
+  "OMIT_REINDEX",
+#endif
+#ifdef SQLITE_OMIT_SCHEMA_PRAGMAS
+  "OMIT_SCHEMA_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS
+  "OMIT_SCHEMA_VERSION_PRAGMAS",
+#endif
+#ifdef SQLITE_OMIT_SEH
+  "OMIT_SEH",
+#endif
+#ifdef SQLITE_OMIT_SHARED_CACHE
+  "OMIT_SHARED_CACHE",
+#endif
+#ifdef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
+  "OMIT_SHUTDOWN_DIRECTORIES",
+#endif
+#ifdef SQLITE_OMIT_SUBQUERY
+  "OMIT_SUBQUERY",
+#endif
+#ifdef SQLITE_OMIT_TCL_VARIABLE
+  "OMIT_TCL_VARIABLE",
+#endif
+#ifdef SQLITE_OMIT_TEMPDB
+  "OMIT_TEMPDB",
+#endif
+#ifdef SQLITE_OMIT_TEST_CONTROL
+  "OMIT_TEST_CONTROL",
+#endif
+#ifdef SQLITE_OMIT_TRACE
+# if SQLITE_OMIT_TRACE != 1
+  "OMIT_TRACE=" CTIMEOPT_VAL(SQLITE_OMIT_TRACE),
+# endif
+#endif
+#ifdef SQLITE_OMIT_TRIGGER
+  "OMIT_TRIGGER",
+#endif
+#ifdef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
+  "OMIT_TRUNCATE_OPTIMIZATION",
+#endif
+#ifdef SQLITE_OMIT_UTF16
+  "OMIT_UTF16",
+#endif
+#ifdef SQLITE_OMIT_VACUUM
+  "OMIT_VACUUM",
+#endif
+#ifdef SQLITE_OMIT_VIEW
+  "OMIT_VIEW",
+#endif
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+  "OMIT_VIRTUALTABLE",
+#endif
+#ifdef SQLITE_OMIT_WAL
+  "OMIT_WAL",
+#endif
+#ifdef SQLITE_OMIT_WSD
+  "OMIT_WSD",
+#endif
+#ifdef SQLITE_OMIT_XFER_OPT
+  "OMIT_XFER_OPT",
+#endif
+#ifdef SQLITE_PERFORMANCE_TRACE
+  "PERFORMANCE_TRACE",
+#endif
+#ifdef SQLITE_POWERSAFE_OVERWRITE
+# if SQLITE_POWERSAFE_OVERWRITE != 1
+  "POWERSAFE_OVERWRITE=" CTIMEOPT_VAL(SQLITE_POWERSAFE_OVERWRITE),
+# endif
+#endif
+#ifdef SQLITE_PREFER_PROXY_LOCKING
+  "PREFER_PROXY_LOCKING",
+#endif
+#ifdef SQLITE_PROXY_DEBUG
+  "PROXY_DEBUG",
+#endif
+#ifdef SQLITE_REVERSE_UNORDERED_SELECTS
+  "REVERSE_UNORDERED_SELECTS",
+#endif
+#ifdef SQLITE_RTREE_INT_ONLY
+  "RTREE_INT_ONLY",
+#endif
+#ifdef SQLITE_SECURE_DELETE
+  "SECURE_DELETE",
+#endif
+#ifdef SQLITE_SMALL_STACK
+  "SMALL_STACK",
+#endif
+#ifdef SQLITE_SORTER_PMASZ
+  "SORTER_PMASZ=" CTIMEOPT_VAL(SQLITE_SORTER_PMASZ),
+#endif
+#ifdef SQLITE_SOUNDEX
+  "SOUNDEX",
+#endif
+#ifdef SQLITE_STAT4_SAMPLES
+  "STAT4_SAMPLES=" CTIMEOPT_VAL(SQLITE_STAT4_SAMPLES),
+#endif
+#ifdef SQLITE_STMTJRNL_SPILL
+  "STMTJRNL_SPILL=" CTIMEOPT_VAL(SQLITE_STMTJRNL_SPILL),
+#endif
+#ifdef SQLITE_SUBSTR_COMPATIBILITY
+  "SUBSTR_COMPATIBILITY",
+#endif
+#if (!defined(SQLITE_WIN32_MALLOC) \
+     && !defined(SQLITE_ZERO_MALLOC) \
+     && !defined(SQLITE_MEMDEBUG) \
+    ) || defined(SQLITE_SYSTEM_MALLOC)
+  "SYSTEM_MALLOC",
+#endif
+#ifdef SQLITE_TCL
+  "TCL",
+#endif
+#ifdef SQLITE_TEMP_STORE
+  "TEMP_STORE=" CTIMEOPT_VAL(SQLITE_TEMP_STORE),
+#endif
+#ifdef SQLITE_TEST
+  "TEST",
+#endif
+#if defined(SQLITE_THREADSAFE)
+  "THREADSAFE=" CTIMEOPT_VAL(SQLITE_THREADSAFE),
+#elif defined(THREADSAFE)
+  "THREADSAFE=" CTIMEOPT_VAL(THREADSAFE),
+#else
+  "THREADSAFE=1",
+#endif
+#ifdef SQLITE_UNLINK_AFTER_CLOSE
+  "UNLINK_AFTER_CLOSE",
+#endif
+#ifdef SQLITE_UNTESTABLE
+  "UNTESTABLE",
+#endif
+#ifdef SQLITE_USE_ALLOCA
+  "USE_ALLOCA",
+#endif
+#ifdef SQLITE_USE_FCNTL_TRACE
+  "USE_FCNTL_TRACE",
+#endif
+#ifdef SQLITE_USE_URI
+  "USE_URI",
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  "VDBE_COVERAGE",
+#endif
+#ifdef SQLITE_WIN32_MALLOC
+  "WIN32_MALLOC",
+#endif
+#ifdef SQLITE_ZERO_MALLOC
+  "ZERO_MALLOC",
+#endif
+
+} ;
+
+SQLITE_PRIVATE const char **sqlite3CompileOptions(int *pnOpt){
+  *pnOpt = sizeof(sqlite3azCompileOpt) / sizeof(sqlite3azCompileOpt[0]);
+  return (const char**)sqlite3azCompileOpt;
+}
+
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/************** End of ctime.c ***********************************************/
+/************** Begin file global.c ******************************************/
+/*
+** 2008 June 13
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains definitions of global variables and constants.
+*/
+/* #include "sqliteInt.h" */
+
+/* An array to map all upper-case characters into their corresponding
+** lower-case character.
+**
+** SQLite only considers US-ASCII (or EBCDIC) characters.  We do not
+** handle case conversions for the UTF character set since the tables
+** involved are nearly as big or bigger than SQLite itself.
+*/
+SQLITE_PRIVATE const unsigned char sqlite3UpperToLower[] = {
+#ifdef SQLITE_ASCII
+      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17,
+     18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
+     36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
+     54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 97, 98, 99,100,101,102,103,
+    104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,
+    122, 91, 92, 93, 94, 95, 96, 97, 98, 99,100,101,102,103,104,105,106,107,
+    108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,
+    126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
+    144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,
+    162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,
+    180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,
+    198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,
+    216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,
+    234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,
+    252,253,254,255,
+#endif
+#ifdef SQLITE_EBCDIC
+      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, /* 0x */
+     16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, /* 1x */
+     32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, /* 2x */
+     48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, /* 3x */
+     64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, /* 4x */
+     80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, /* 5x */
+     96, 97, 98, 99,100,101,102,103,104,105,106,107,108,109,110,111, /* 6x */
+    112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127, /* 7x */
+    128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143, /* 8x */
+    144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159, /* 9x */
+    160,161,162,163,164,165,166,167,168,169,170,171,140,141,142,175, /* Ax */
+    176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191, /* Bx */
+    192,129,130,131,132,133,134,135,136,137,202,203,204,205,206,207, /* Cx */
+    208,145,146,147,148,149,150,151,152,153,218,219,220,221,222,223, /* Dx */
+    224,225,162,163,164,165,166,167,168,169,234,235,236,237,238,239, /* Ex */
+    240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255, /* Fx */
+#endif
+/* All of the upper-to-lower conversion data is above.  The following
+** 18 integers are completely unrelated.  They are appended to the
+** sqlite3UpperToLower[] array to avoid UBSAN warnings.  Here's what is
+** going on:
+**
+** The SQL comparison operators (<>, =, >, <=, <, and >=) are implemented
+** by invoking sqlite3MemCompare(A,B) which compares values A and B and
+** returns negative, zero, or positive if A is less then, equal to, or
+** greater than B, respectively.  Then the true false results is found by
+** consulting sqlite3aLTb[opcode], sqlite3aEQb[opcode], or
+** sqlite3aGTb[opcode] depending on whether the result of compare(A,B)
+** is negative, zero, or positive, where opcode is the specific opcode.
+** The only works because the comparison opcodes are consecutive and in
+** this order: NE EQ GT LE LT GE.  Various assert()s throughout the code
+** ensure that is the case.
+**
+** These elements must be appended to another array.  Otherwise the
+** index (here shown as [256-OP_Ne]) would be out-of-bounds and thus
+** be undefined behavior.  That's goofy, but the C-standards people thought
+** it was a good idea, so here we are.
+*/
+/* NE  EQ  GT  LE  LT  GE  */
+   1,  0,  0,  1,  1,  0,  /* aLTb[]: Use when compare(A,B) less than zero */
+   0,  1,  0,  1,  0,  1,  /* aEQb[]: Use when compare(A,B) equals zero */
+   1,  0,  1,  0,  0,  1   /* aGTb[]: Use when compare(A,B) greater than zero*/
+};
+SQLITE_PRIVATE const unsigned char *sqlite3aLTb = &sqlite3UpperToLower[256-OP_Ne];
+SQLITE_PRIVATE const unsigned char *sqlite3aEQb = &sqlite3UpperToLower[256+6-OP_Ne];
+SQLITE_PRIVATE const unsigned char *sqlite3aGTb = &sqlite3UpperToLower[256+12-OP_Ne];
+
+/*
+** The following 256 byte lookup table is used to support SQLites built-in
+** equivalents to the following standard library functions:
+**
+**   isspace()                        0x01
+**   isalpha()                        0x02
+**   isdigit()                        0x04
+**   isalnum()                        0x06
+**   isxdigit()                       0x08
+**   toupper()                        0x20
+**   SQLite identifier character      0x40   $, _, or non-ascii
+**   Quote character                  0x80
+**
+** Bit 0x20 is set if the mapped character requires translation to upper
+** case. i.e. if the character is a lower-case ASCII character.
+** If x is a lower-case ASCII character, then its upper-case equivalent
+** is (x - 0x20). Therefore toupper() can be implemented as:
+**
+**   (x & ~(map[x]&0x20))
+**
+** The equivalent of tolower() is implemented using the sqlite3UpperToLower[]
+** array. tolower() is used more often than toupper() by SQLite.
+**
+** Bit 0x40 is set if the character is non-alphanumeric and can be used in an
+** SQLite identifier.  Identifiers are alphanumerics, "_", "$", and any
+** non-ASCII UTF character. Hence the test for whether or not a character is
+** part of an identifier is 0x46.
+*/
+SQLITE_PRIVATE const unsigned char sqlite3CtypeMap[256] = {
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 00..07    ........ */
+  0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00,  /* 08..0f    ........ */
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 10..17    ........ */
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 18..1f    ........ */
+  0x01, 0x00, 0x80, 0x00, 0x40, 0x00, 0x00, 0x80,  /* 20..27     !"#$%&' */
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 28..2f    ()*+,-./ */
+  0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c,  /* 30..37    01234567 */
+  0x0c, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 38..3f    89:;<=>? */
+
+  0x00, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x02,  /* 40..47    @ABCDEFG */
+  0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,  /* 48..4f    HIJKLMNO */
+  0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,  /* 50..57    PQRSTUVW */
+  0x02, 0x02, 0x02, 0x80, 0x00, 0x00, 0x00, 0x40,  /* 58..5f    XYZ[\]^_ */
+  0x80, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x22,  /* 60..67    `abcdefg */
+  0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,  /* 68..6f    hijklmno */
+  0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,  /* 70..77    pqrstuvw */
+  0x22, 0x22, 0x22, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 78..7f    xyz{|}~. */
+
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 80..87    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 88..8f    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 90..97    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* 98..9f    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* a0..a7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* a8..af    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* b0..b7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* b8..bf    ........ */
+
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* c0..c7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* c8..cf    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* d0..d7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* d8..df    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e0..e7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* e8..ef    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,  /* f0..f7    ........ */
+  0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40   /* f8..ff    ........ */
+};
+
+/* EVIDENCE-OF: R-02982-34736 In order to maintain full backwards
+** compatibility for legacy applications, the URI filename capability is
+** disabled by default.
+**
+** EVIDENCE-OF: R-38799-08373 URI filenames can be enabled or disabled
+** using the SQLITE_USE_URI=1 or SQLITE_USE_URI=0 compile-time options.
+**
+** EVIDENCE-OF: R-43642-56306 By default, URI handling is globally
+** disabled. The default value may be changed by compiling with the
+** SQLITE_USE_URI symbol defined.
+*/
+#ifndef SQLITE_USE_URI
+# define SQLITE_USE_URI 0
+#endif
+
+/* EVIDENCE-OF: R-38720-18127 The default setting is determined by the
+** SQLITE_ALLOW_COVERING_INDEX_SCAN compile-time option, or is "on" if
+** that compile-time option is omitted.
+*/
+#if !defined(SQLITE_ALLOW_COVERING_INDEX_SCAN)
+# define SQLITE_ALLOW_COVERING_INDEX_SCAN 1
+#else
+# if !SQLITE_ALLOW_COVERING_INDEX_SCAN
+#   error "Compile-time disabling of covering index scan using the\
+ -DSQLITE_ALLOW_COVERING_INDEX_SCAN=0 option is deprecated.\
+ Contact SQLite developers if this is a problem for you, and\
+ delete this #error macro to continue with your build."
+# endif
+#endif
+
+/* The minimum PMA size is set to this value multiplied by the database
+** page size in bytes.
+*/
+#ifndef SQLITE_SORTER_PMASZ
+# define SQLITE_SORTER_PMASZ 250
+#endif
+
+/* Statement journals spill to disk when their size exceeds the following
+** threshold (in bytes). 0 means that statement journals are created and
+** written to disk immediately (the default behavior for SQLite versions
+** before 3.12.0).  -1 means always keep the entire statement journal in
+** memory.  (The statement journal is also always held entirely in memory
+** if journal_mode=MEMORY or if temp_store=MEMORY, regardless of this
+** setting.)
+*/
+#ifndef SQLITE_STMTJRNL_SPILL
+# define SQLITE_STMTJRNL_SPILL (64*1024)
+#endif
+
+/*
+** The default lookaside-configuration, the format "SZ,N".  SZ is the
+** number of bytes in each lookaside slot (should be a multiple of 8)
+** and N is the number of slots.  The lookaside-configuration can be
+** changed as start-time using sqlite3_config(SQLITE_CONFIG_LOOKASIDE)
+** or at run-time for an individual database connection using
+** sqlite3_db_config(db, SQLITE_DBCONFIG_LOOKASIDE);
+**
+** With the two-size-lookaside enhancement, less lookaside is required.
+** The default configuration of 1200,40 actually provides 30 1200-byte slots
+** and 93 128-byte slots, which is more lookaside than is available
+** using the older 1200,100 configuration without two-size-lookaside.
+*/
+#ifndef SQLITE_DEFAULT_LOOKASIDE
+# ifdef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+#   define SQLITE_DEFAULT_LOOKASIDE 1200,100  /* 120KB of memory */
+# else
+#   define SQLITE_DEFAULT_LOOKASIDE 1200,40   /* 48KB of memory */
+# endif
+#endif
+
+
+/* The default maximum size of an in-memory database created using
+** sqlite3_deserialize()
+*/
+#ifndef SQLITE_MEMDB_DEFAULT_MAXSIZE
+# define SQLITE_MEMDB_DEFAULT_MAXSIZE 1073741824
+#endif
+
+/*
+** The following singleton contains the global configuration for
+** the SQLite library.
+*/
+SQLITE_PRIVATE SQLITE_WSD struct Sqlite3Config sqlite3Config = {
+   SQLITE_DEFAULT_MEMSTATUS,  /* bMemstat */
+   1,                         /* bCoreMutex */
+   SQLITE_THREADSAFE==1,      /* bFullMutex */
+   SQLITE_USE_URI,            /* bOpenUri */
+   SQLITE_ALLOW_COVERING_INDEX_SCAN,   /* bUseCis */
+   0,                         /* bSmallMalloc */
+   1,                         /* bExtraSchemaChecks */
+#ifdef SQLITE_DEBUG
+   0,                         /* bJsonSelfcheck */
+#endif
+   0x7ffffffe,                /* mxStrlen */
+   0,                         /* neverCorrupt */
+   SQLITE_DEFAULT_LOOKASIDE,  /* szLookaside, nLookaside */
+   SQLITE_STMTJRNL_SPILL,     /* nStmtSpill */
+   {0,0,0,0,0,0,0,0},         /* m */
+   {0,0,0,0,0,0,0,0,0},       /* mutex */
+   {0,0,0,0,0,0,0,0,0,0,0,0,0},/* pcache2 */
+   (void*)0,                  /* pHeap */
+   0,                         /* nHeap */
+   0, 0,                      /* mnHeap, mxHeap */
+   SQLITE_DEFAULT_MMAP_SIZE,  /* szMmap */
+   SQLITE_MAX_MMAP_SIZE,      /* mxMmap */
+   (void*)0,                  /* pPage */
+   0,                         /* szPage */
+   SQLITE_DEFAULT_PCACHE_INITSZ, /* nPage */
+   0,                         /* mxParserStack */
+   0,                         /* sharedCacheEnabled */
+   SQLITE_SORTER_PMASZ,       /* szPma */
+   /* All the rest should always be initialized to zero */
+   0,                         /* isInit */
+   0,                         /* inProgress */
+   0,                         /* isMutexInit */
+   0,                         /* isMallocInit */
+   0,                         /* isPCacheInit */
+   0,                         /* nRefInitMutex */
+   0,                         /* pInitMutex */
+   0,                         /* xLog */
+   0,                         /* pLogArg */
+#ifdef SQLITE_ENABLE_SQLLOG
+   0,                         /* xSqllog */
+   0,                         /* pSqllogArg */
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+   0,                         /* xVdbeBranch */
+   0,                         /* pVbeBranchArg */
+#endif
+#ifndef SQLITE_OMIT_DESERIALIZE
+   SQLITE_MEMDB_DEFAULT_MAXSIZE,   /* mxMemdbSize */
+#endif
+#ifndef SQLITE_UNTESTABLE
+   0,                         /* xTestCallback */
+#endif
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+   0,                         /* mNoVisibleRowid.  0 == allow rowid-in-view */
+#endif
+   0,                         /* bLocaltimeFault */
+   0,                         /* xAltLocaltime */
+   0x7ffffffe,                /* iOnceResetThreshold */
+   SQLITE_DEFAULT_SORTERREF_SIZE,   /* szSorterRef */
+   0,                         /* iPrngSeed */
+#ifdef SQLITE_DEBUG
+   {0,0,0,0,0,0},             /* aTune */
+#endif
+};
+
+/*
+** Hash table for global functions - functions common to all
+** database connections.  After initialization, this table is
+** read-only.
+*/
+SQLITE_PRIVATE FuncDefHash sqlite3BuiltinFunctions;
+
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_DEBUG)
+/*
+** Counter used for coverage testing.  Does not come into play for
+** release builds.
+**
+** Access to this global variable is not mutex protected.  This might
+** result in TSAN warnings.  But as the variable does not exist in
+** release builds, that should not be a concern.
+*/
+SQLITE_PRIVATE unsigned int sqlite3CoverageCounter;
+#endif /* SQLITE_COVERAGE_TEST || SQLITE_DEBUG */
+
+#ifdef VDBE_PROFILE
+/*
+** The following performance counter can be used in place of
+** sqlite3Hwtime() for profiling.  This is a no-op on standard builds.
+*/
+SQLITE_PRIVATE sqlite3_uint64 sqlite3NProfileCnt = 0;
+#endif
+
+/*
+** The value of the "pending" byte must be 0x40000000 (1 byte past the
+** 1-gibabyte boundary) in a compatible database.  SQLite never uses
+** the database page that contains the pending byte.  It never attempts
+** to read or write that page.  The pending byte page is set aside
+** for use by the VFS layers as space for managing file locks.
+**
+** During testing, it is often desirable to move the pending byte to
+** a different position in the file.  This allows code that has to
+** deal with the pending byte to run on files that are much smaller
+** than 1 GiB.  The sqlite3_test_control() interface can be used to
+** move the pending byte.
+**
+** IMPORTANT:  Changing the pending byte to any value other than
+** 0x40000000 results in an incompatible database file format!
+** Changing the pending byte during operation will result in undefined
+** and incorrect behavior.
+*/
+#ifndef SQLITE_OMIT_WSD
+SQLITE_PRIVATE int sqlite3PendingByte = 0x40000000;
+#endif
+
+/*
+** Tracing flags set by SQLITE_TESTCTRL_TRACEFLAGS.
+*/
+SQLITE_PRIVATE u32 sqlite3TreeTrace = 0;
+SQLITE_PRIVATE u32 sqlite3WhereTrace = 0;
+
+/* #include "opcodes.h" */
+/*
+** Properties of opcodes.  The OPFLG_INITIALIZER macro is
+** created by mkopcodeh.awk during compilation.  Data is obtained
+** from the comments following the "case OP_xxxx:" statements in
+** the vdbe.c file.
+*/
+SQLITE_PRIVATE const unsigned char sqlite3OpcodeProperty[] = OPFLG_INITIALIZER;
+
+/*
+** Name of the default collating sequence
+*/
+SQLITE_PRIVATE const char sqlite3StrBINARY[] = "BINARY";
+
+/*
+** Standard typenames.  These names must match the COLTYPE_* definitions.
+** Adjust the SQLITE_N_STDTYPE value if adding or removing entries.
+**
+**    sqlite3StdType[]            The actual names of the datatypes.
+**
+**    sqlite3StdTypeLen[]         The length (in bytes) of each entry
+**                                in sqlite3StdType[].
+**
+**    sqlite3StdTypeAffinity[]    The affinity associated with each entry
+**                                in sqlite3StdType[].
+*/
+SQLITE_PRIVATE const unsigned char sqlite3StdTypeLen[] = { 3, 4, 3, 7, 4, 4 };
+SQLITE_PRIVATE const char sqlite3StdTypeAffinity[] = {
+  SQLITE_AFF_NUMERIC,
+  SQLITE_AFF_BLOB,
+  SQLITE_AFF_INTEGER,
+  SQLITE_AFF_INTEGER,
+  SQLITE_AFF_REAL,
+  SQLITE_AFF_TEXT
+};
+SQLITE_PRIVATE const char *sqlite3StdType[] = {
+  "ANY",
+  "BLOB",
+  "INT",
+  "INTEGER",
+  "REAL",
+  "TEXT"
+};
+
+/************** End of global.c **********************************************/
+/************** Begin file status.c ******************************************/
+/*
+** 2008 June 18
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This module implements the sqlite3_status() interface and related
+** functionality.
+*/
+/* #include "sqliteInt.h" */
+/************** Include vdbeInt.h in the middle of status.c ******************/
+/************** Begin file vdbeInt.h *****************************************/
+/*
+** 2003 September 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for information that is private to the
+** VDBE.  This information used to all be at the top of the single
+** source code file "vdbe.c".  When that file became too big (over
+** 6000 lines long) it was split up into several smaller files and
+** this header information was factored out.
+*/
+#ifndef SQLITE_VDBEINT_H
+#define SQLITE_VDBEINT_H
+
+/*
+** The maximum number of times that a statement will try to reparse
+** itself before giving up and returning SQLITE_SCHEMA.
+*/
+#ifndef SQLITE_MAX_SCHEMA_RETRY
+# define SQLITE_MAX_SCHEMA_RETRY 50
+#endif
+
+/*
+** VDBE_DISPLAY_P4 is true or false depending on whether or not the
+** "explain" P4 display logic is enabled.
+*/
+#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
+     || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG) \
+     || defined(SQLITE_ENABLE_BYTECODE_VTAB)
+# define VDBE_DISPLAY_P4 1
+#else
+# define VDBE_DISPLAY_P4 0
+#endif
+
+/*
+** SQL is translated into a sequence of instructions to be
+** executed by a virtual machine.  Each instruction is an instance
+** of the following structure.
+*/
+typedef struct VdbeOp Op;
+
+/*
+** Boolean values
+*/
+typedef unsigned Bool;
+
+/* Opaque type used by code in vdbesort.c */
+typedef struct VdbeSorter VdbeSorter;
+
+/* Elements of the linked list at Vdbe.pAuxData */
+typedef struct AuxData AuxData;
+
+/* A cache of large TEXT or BLOB values in a VdbeCursor */
+typedef struct VdbeTxtBlbCache VdbeTxtBlbCache;
+
+/* Types of VDBE cursors */
+#define CURTYPE_BTREE       0
+#define CURTYPE_SORTER      1
+#define CURTYPE_VTAB        2
+#define CURTYPE_PSEUDO      3
+
+/*
+** A VdbeCursor is an superclass (a wrapper) for various cursor objects:
+**
+**      * A b-tree cursor
+**          -  In the main database or in an ephemeral database
+**          -  On either an index or a table
+**      * A sorter
+**      * A virtual table
+**      * A one-row "pseudotable" stored in a single register
+*/
+typedef struct VdbeCursor VdbeCursor;
+struct VdbeCursor {
+  u8 eCurType;            /* One of the CURTYPE_* values above */
+  i8 iDb;                 /* Index of cursor database in db->aDb[] */
+  u8 nullRow;             /* True if pointing to a row with no data */
+  u8 deferredMoveto;      /* A call to sqlite3BtreeMoveto() is needed */
+  u8 isTable;             /* True for rowid tables.  False for indexes */
+#ifdef SQLITE_DEBUG
+  u8 seekOp;              /* Most recent seek operation on this cursor */
+  u8 wrFlag;              /* The wrFlag argument to sqlite3BtreeCursor() */
+#endif
+  Bool isEphemeral:1;     /* True for an ephemeral table */
+  Bool useRandomRowid:1;  /* Generate new record numbers semi-randomly */
+  Bool isOrdered:1;       /* True if the table is not BTREE_UNORDERED */
+  Bool noReuse:1;         /* OpenEphemeral may not reuse this cursor */
+  Bool colCache:1;        /* pCache pointer is initialized and non-NULL */
+  u16 seekHit;            /* See the OP_SeekHit and OP_IfNoHope opcodes */
+  union {                 /* pBtx for isEphermeral.  pAltMap otherwise */
+    Btree *pBtx;            /* Separate file holding temporary table */
+    u32 *aAltMap;           /* Mapping from table to index column numbers */
+  } ub;
+  i64 seqCount;           /* Sequence counter */
+
+  /* Cached OP_Column parse information is only valid if cacheStatus matches
+  ** Vdbe.cacheCtr.  Vdbe.cacheCtr will never take on the value of
+  ** CACHE_STALE (0) and so setting cacheStatus=CACHE_STALE guarantees that
+  ** the cache is out of date. */
+  u32 cacheStatus;        /* Cache is valid if this matches Vdbe.cacheCtr */
+  int seekResult;         /* Result of previous sqlite3BtreeMoveto() or 0
+                          ** if there have been no prior seeks on the cursor. */
+  /* seekResult does not distinguish between "no seeks have ever occurred
+  ** on this cursor" and "the most recent seek was an exact match".
+  ** For CURTYPE_PSEUDO, seekResult is the register holding the record */
+
+  /* When a new VdbeCursor is allocated, only the fields above are zeroed.
+  ** The fields that follow are uninitialized, and must be individually
+  ** initialized prior to first use. */
+  VdbeCursor *pAltCursor; /* Associated index cursor from which to read */
+  union {
+    BtCursor *pCursor;          /* CURTYPE_BTREE or _PSEUDO.  Btree cursor */
+    sqlite3_vtab_cursor *pVCur; /* CURTYPE_VTAB.              Vtab cursor */
+    VdbeSorter *pSorter;        /* CURTYPE_SORTER.            Sorter object */
+  } uc;
+  KeyInfo *pKeyInfo;      /* Info about index keys needed by index cursors */
+  u32 iHdrOffset;         /* Offset to next unparsed byte of the header */
+  Pgno pgnoRoot;          /* Root page of the open btree cursor */
+  i16 nField;             /* Number of fields in the header */
+  u16 nHdrParsed;         /* Number of header fields parsed so far */
+  i64 movetoTarget;       /* Argument to the deferred sqlite3BtreeMoveto() */
+  u32 *aOffset;           /* Pointer to aType[nField] */
+  const u8 *aRow;         /* Data for the current row, if all on one page */
+  u32 payloadSize;        /* Total number of bytes in the record */
+  u32 szRow;              /* Byte available in aRow */
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+  u64 maskUsed;           /* Mask of columns used by this cursor */
+#endif
+  VdbeTxtBlbCache *pCache; /* Cache of large TEXT or BLOB values */
+
+  /* 2*nField extra array elements allocated for aType[], beyond the one
+  ** static element declared in the structure.  nField total array slots for
+  ** aType[] and nField+1 array slots for aOffset[] */
+  u32 aType[1];           /* Type values record decode.  MUST BE LAST */
+};
+
+/* Return true if P is a null-only cursor
+*/
+#define IsNullCursor(P) \
+  ((P)->eCurType==CURTYPE_PSEUDO && (P)->nullRow && (P)->seekResult==0)
+
+/*
+** A value for VdbeCursor.cacheStatus that means the cache is always invalid.
+*/
+#define CACHE_STALE 0
+
+/*
+** Large TEXT or BLOB values can be slow to load, so we want to avoid
+** loading them more than once.  For that reason, large TEXT and BLOB values
+** can be stored in a cache defined by this object, and attached to the
+** VdbeCursor using the pCache field.
+*/
+struct VdbeTxtBlbCache {
+  char *pCValue;        /* A RCStr buffer to hold the value */
+  i64 iOffset;          /* File offset of the row being cached */
+  int iCol;             /* Column for which the cache is valid */
+  u32 cacheStatus;      /* Vdbe.cacheCtr value */
+  u32 colCacheCtr;      /* Column cache counter */
+};
+
+/*
+** When a sub-program is executed (OP_Program), a structure of this type
+** is allocated to store the current value of the program counter, as
+** well as the current memory cell array and various other frame specific
+** values stored in the Vdbe struct. When the sub-program is finished,
+** these values are copied back to the Vdbe from the VdbeFrame structure,
+** restoring the state of the VM to as it was before the sub-program
+** began executing.
+**
+** The memory for a VdbeFrame object is allocated and managed by a memory
+** cell in the parent (calling) frame. When the memory cell is deleted or
+** overwritten, the VdbeFrame object is not freed immediately. Instead, it
+** is linked into the Vdbe.pDelFrame list. The contents of the Vdbe.pDelFrame
+** list is deleted when the VM is reset in VdbeHalt(). The reason for doing
+** this instead of deleting the VdbeFrame immediately is to avoid recursive
+** calls to sqlite3VdbeMemRelease() when the memory cells belonging to the
+** child frame are released.
+**
+** The currently executing frame is stored in Vdbe.pFrame. Vdbe.pFrame is
+** set to NULL if the currently executing frame is the main program.
+*/
+typedef struct VdbeFrame VdbeFrame;
+struct VdbeFrame {
+  Vdbe *v;                /* VM this frame belongs to */
+  VdbeFrame *pParent;     /* Parent of this frame, or NULL if parent is main */
+  Op *aOp;                /* Program instructions for parent frame */
+  Mem *aMem;              /* Array of memory cells for parent frame */
+  VdbeCursor **apCsr;     /* Array of Vdbe cursors for parent frame */
+  u8 *aOnce;              /* Bitmask used by OP_Once */
+  void *token;            /* Copy of SubProgram.token */
+  i64 lastRowid;          /* Last insert rowid (sqlite3.lastRowid) */
+  AuxData *pAuxData;      /* Linked list of auxdata allocations */
+#if SQLITE_DEBUG
+  u32 iFrameMagic;        /* magic number for sanity checking */
+#endif
+  int nCursor;            /* Number of entries in apCsr */
+  int pc;                 /* Program Counter in parent (calling) frame */
+  int nOp;                /* Size of aOp array */
+  int nMem;               /* Number of entries in aMem */
+  int nChildMem;          /* Number of memory cells for child frame */
+  int nChildCsr;          /* Number of cursors for child frame */
+  i64 nChange;            /* Statement changes (Vdbe.nChange)     */
+  i64 nDbChange;          /* Value of db->nChange */
+};
+
+/* Magic number for sanity checking on VdbeFrame objects */
+#define SQLITE_FRAME_MAGIC 0x879fb71e
+
+/*
+** Return a pointer to the array of registers allocated for use
+** by a VdbeFrame.
+*/
+#define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))])
+
+/*
+** Internally, the vdbe manipulates nearly all SQL values as Mem
+** structures. Each Mem struct may cache multiple representations (string,
+** integer etc.) of the same value.
+*/
+struct sqlite3_value {
+  union MemValue {
+    double r;           /* Real value used when MEM_Real is set in flags */
+    i64 i;              /* Integer value used when MEM_Int is set in flags */
+    int nZero;          /* Extra zero bytes when MEM_Zero and MEM_Blob set */
+    const char *zPType; /* Pointer type when MEM_Term|MEM_Subtype|MEM_Null */
+    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
+  } u;
+  char *z;            /* String or BLOB value */
+  int n;              /* Number of characters in string value, excluding '\0' */
+  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
+  u8  enc;            /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
+  u8  eSubtype;       /* Subtype for this value */
+  /* ShallowCopy only needs to copy the information above */
+  sqlite3 *db;        /* The associated database connection */
+  int szMalloc;       /* Size of the zMalloc allocation */
+  u32 uTemp;          /* Transient storage for serial_type in OP_MakeRecord */
+  char *zMalloc;      /* Space to hold MEM_Str or MEM_Blob if szMalloc>0 */
+  void (*xDel)(void*);/* Destructor for Mem.z - only valid if MEM_Dyn */
+#ifdef SQLITE_DEBUG
+  Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
+  u16 mScopyFlags;    /* flags value immediately after the shallow copy */
+  u8  bScopy;         /* The pScopyFrom of some other Mem *might* point here */
+#endif
+};
+
+/*
+** Size of struct Mem not including the Mem.zMalloc member or anything that
+** follows.
+*/
+#define MEMCELLSIZE offsetof(Mem,db)
+
+/* One or more of the following flags are set to indicate the
+** representations of the value stored in the Mem struct.
+**
+**  *  MEM_Null                An SQL NULL value
+**
+**  *  MEM_Null|MEM_Zero       An SQL NULL with the virtual table
+**                             UPDATE no-change flag set
+**
+**  *  MEM_Null|MEM_Term|      An SQL NULL, but also contains a
+**        MEM_Subtype          pointer accessible using
+**                             sqlite3_value_pointer().
+**
+**  *  MEM_Null|MEM_Cleared    Special SQL NULL that compares non-equal
+**                             to other NULLs even using the IS operator.
+**
+**  *  MEM_Str                 A string, stored in Mem.z with
+**                             length Mem.n.  Zero-terminated if
+**                             MEM_Term is set.  This flag is
+**                             incompatible with MEM_Blob and
+**                             MEM_Null, but can appear with MEM_Int,
+**                             MEM_Real, and MEM_IntReal.
+**
+**  *  MEM_Blob                A blob, stored in Mem.z length Mem.n.
+**                             Incompatible with MEM_Str, MEM_Null,
+**                             MEM_Int, MEM_Real, and MEM_IntReal.
+**
+**  *  MEM_Blob|MEM_Zero       A blob in Mem.z of length Mem.n plus
+**                             MEM.u.i extra 0x00 bytes at the end.
+**
+**  *  MEM_Int                 Integer stored in Mem.u.i.
+**
+**  *  MEM_Real                Real stored in Mem.u.r.
+**
+**  *  MEM_IntReal             Real stored as an integer in Mem.u.i.
+**
+** If the MEM_Null flag is set, then the value is an SQL NULL value.
+** For a pointer type created using sqlite3_bind_pointer() or
+** sqlite3_result_pointer() the MEM_Term and MEM_Subtype flags are also set.
+**
+** If the MEM_Str flag is set then Mem.z points at a string representation.
+** Usually this is encoded in the same unicode encoding as the main
+** database (see below for exceptions). If the MEM_Term flag is also
+** set, then the string is nul terminated. The MEM_Int and MEM_Real
+** flags may coexist with the MEM_Str flag.
+*/
+#define MEM_Undefined 0x0000   /* Value is undefined */
+#define MEM_Null      0x0001   /* Value is NULL (or a pointer) */
+#define MEM_Str       0x0002   /* Value is a string */
+#define MEM_Int       0x0004   /* Value is an integer */
+#define MEM_Real      0x0008   /* Value is a real number */
+#define MEM_Blob      0x0010   /* Value is a BLOB */
+#define MEM_IntReal   0x0020   /* MEM_Int that stringifies like MEM_Real */
+#define MEM_AffMask   0x003f   /* Mask of affinity bits */
+
+/* Extra bits that modify the meanings of the core datatypes above
+*/
+#define MEM_FromBind  0x0040   /* Value originates from sqlite3_bind() */
+ /*                   0x0080   // Available */
+#define MEM_Cleared   0x0100   /* NULL set by OP_Null, not from data */
+#define MEM_Term      0x0200   /* String in Mem.z is zero terminated */
+#define MEM_Zero      0x0400   /* Mem.i contains count of 0s appended to blob */
+#define MEM_Subtype   0x0800   /* Mem.eSubtype is valid */
+#define MEM_TypeMask  0x0dbf   /* Mask of type bits */
+
+/* Bits that determine the storage for Mem.z for a string or blob or
+** aggregate accumulator.
+*/
+#define MEM_Dyn       0x1000   /* Need to call Mem.xDel() on Mem.z */
+#define MEM_Static    0x2000   /* Mem.z points to a static string */
+#define MEM_Ephem     0x4000   /* Mem.z points to an ephemeral string */
+#define MEM_Agg       0x8000   /* Mem.z points to an agg function context */
+
+/* Return TRUE if Mem X contains dynamically allocated content - anything
+** that needs to be deallocated to avoid a leak.
+*/
+#define VdbeMemDynamic(X)  \
+  (((X)->flags&(MEM_Agg|MEM_Dyn))!=0)
+
+/*
+** Clear any existing type flags from a Mem and replace them with f
+*/
+#define MemSetTypeFlag(p, f) \
+   ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f)
+
+/*
+** True if Mem X is a NULL-nochng type.
+*/
+#define MemNullNochng(X) \
+  (((X)->flags&MEM_TypeMask)==(MEM_Null|MEM_Zero) \
+    && (X)->n==0 && (X)->u.nZero==0)
+
+/*
+** Return true if a memory cell has been initialized and is valid.
+** is for use inside assert() statements only.
+**
+** A Memory cell is initialized if at least one of the
+** MEM_Null, MEM_Str, MEM_Int, MEM_Real, MEM_Blob, or MEM_IntReal bits
+** is set.  It is "undefined" if all those bits are zero.
+*/
+#ifdef SQLITE_DEBUG
+#define memIsValid(M)  ((M)->flags & MEM_AffMask)!=0
+#endif
+
+/*
+** Each auxiliary data pointer stored by a user defined function
+** implementation calling sqlite3_set_auxdata() is stored in an instance
+** of this structure. All such structures associated with a single VM
+** are stored in a linked list headed at Vdbe.pAuxData. All are destroyed
+** when the VM is halted (if not before).
+*/
+struct AuxData {
+  int iAuxOp;                     /* Instruction number of OP_Function opcode */
+  int iAuxArg;                    /* Index of function argument. */
+  void *pAux;                     /* Aux data pointer */
+  void (*xDeleteAux)(void*);      /* Destructor for the aux data */
+  AuxData *pNextAux;              /* Next element in list */
+};
+
+/*
+** The "context" argument for an installable function.  A pointer to an
+** instance of this structure is the first argument to the routines used
+** implement the SQL functions.
+**
+** There is a typedef for this structure in sqlite.h.  So all routines,
+** even the public interface to SQLite, can use a pointer to this structure.
+** But this file is the only place where the internal details of this
+** structure are known.
+**
+** This structure is defined inside of vdbeInt.h because it uses substructures
+** (Mem) which are only defined there.
+*/
+struct sqlite3_context {
+  Mem *pOut;              /* The return value is stored here */
+  FuncDef *pFunc;         /* Pointer to function information */
+  Mem *pMem;              /* Memory cell used to store aggregate context */
+  Vdbe *pVdbe;            /* The VM that owns this context */
+  int iOp;                /* Instruction number of OP_Function */
+  int isError;            /* Error code returned by the function. */
+  u8 enc;                 /* Encoding to use for results */
+  u8 skipFlag;            /* Skip accumulator loading if true */
+  u16 argc;               /* Number of arguments */
+  sqlite3_value *argv[1]; /* Argument set */
+};
+
+/* A bitfield type for use inside of structures.  Always follow with :N where
+** N is the number of bits.
+*/
+typedef unsigned bft;  /* Bit Field Type */
+
+/* The ScanStatus object holds a single value for the
+** sqlite3_stmt_scanstatus() interface.
+**
+** aAddrRange[]:
+**   This array is used by ScanStatus elements associated with EQP
+**   notes that make an SQLITE_SCANSTAT_NCYCLE value available. It is
+**   an array of up to 3 ranges of VM addresses for which the Vdbe.anCycle[]
+**   values should be summed to calculate the NCYCLE value. Each pair of
+**   integer addresses is a start and end address (both inclusive) for a range
+**   instructions. A start value of 0 indicates an empty range.
+*/
+typedef struct ScanStatus ScanStatus;
+struct ScanStatus {
+  int addrExplain;                /* OP_Explain for loop */
+  int aAddrRange[6];
+  int addrLoop;                   /* Address of "loops" counter */
+  int addrVisit;                  /* Address of "rows visited" counter */
+  int iSelectID;                  /* The "Select-ID" for this loop */
+  LogEst nEst;                    /* Estimated output rows per loop */
+  char *zName;                    /* Name of table or index */
+};
+
+/* The DblquoteStr object holds the text of a double-quoted
+** string for a prepared statement.  A linked list of these objects
+** is constructed during statement parsing and is held on Vdbe.pDblStr.
+** When computing a normalized SQL statement for an SQL statement, that
+** list is consulted for each double-quoted identifier to see if the
+** identifier should really be a string literal.
+*/
+typedef struct DblquoteStr DblquoteStr;
+struct DblquoteStr {
+  DblquoteStr *pNextStr;   /* Next string literal in the list */
+  char z[8];               /* Dequoted value for the string */
+};
+
+/*
+** An instance of the virtual machine.  This structure contains the complete
+** state of the virtual machine.
+**
+** The "sqlite3_stmt" structure pointer that is returned by sqlite3_prepare()
+** is really a pointer to an instance of this structure.
+*/
+struct Vdbe {
+  sqlite3 *db;            /* The database connection that owns this statement */
+  Vdbe **ppVPrev,*pVNext; /* Linked list of VDBEs with the same Vdbe.db */
+  Parse *pParse;          /* Parsing context used to create this Vdbe */
+  ynVar nVar;             /* Number of entries in aVar[] */
+  int nMem;               /* Number of memory locations currently allocated */
+  int nCursor;            /* Number of slots in apCsr[] */
+  u32 cacheCtr;           /* VdbeCursor row cache generation counter */
+  int pc;                 /* The program counter */
+  int rc;                 /* Value to return */
+  i64 nChange;            /* Number of db changes made since last reset */
+  int iStatement;         /* Statement number (or 0 if has no opened stmt) */
+  i64 iCurrentTime;       /* Value of julianday('now') for this statement */
+  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
+  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
+  i64 nStmtDefImmCons;    /* Number of def. imm constraints when stmt started */
+  Mem *aMem;              /* The memory locations */
+  Mem **apArg;            /* Arguments to currently executing user function */
+  VdbeCursor **apCsr;     /* One element of this array for each open cursor */
+  Mem *aVar;              /* Values for the OP_Variable opcode. */
+
+  /* When allocating a new Vdbe object, all of the fields below should be
+  ** initialized to zero or NULL */
+
+  Op *aOp;                /* Space to hold the virtual machine's program */
+  int nOp;                /* Number of instructions in the program */
+  int nOpAlloc;           /* Slots allocated for aOp[] */
+  Mem *aColName;          /* Column names to return */
+  Mem *pResultRow;        /* Current output row */
+  char *zErrMsg;          /* Error message written here */
+  VList *pVList;          /* Name of variables */
+#ifndef SQLITE_OMIT_TRACE
+  i64 startTime;          /* Time when query started - used for profiling */
+#endif
+#ifdef SQLITE_DEBUG
+  int rcApp;              /* errcode set by sqlite3_result_error_code() */
+  u32 nWrite;             /* Number of write operations that have occurred */
+#endif
+  u16 nResColumn;         /* Number of columns in one row of the result set */
+  u16 nResAlloc;          /* Column slots allocated to aColName[] */
+  u8 errorAction;         /* Recovery action to do in case of an error */
+  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
+  u8 prepFlags;           /* SQLITE_PREPARE_* flags */
+  u8 eVdbeState;          /* On of the VDBE_*_STATE values */
+  bft expired:2;          /* 1: recompile VM immediately  2: when convenient */
+  bft explain:2;          /* 0: normal, 1: EXPLAIN, 2: EXPLAIN QUERY PLAN */
+  bft changeCntOn:1;      /* True to update the change-counter */
+  bft usesStmtJournal:1;  /* True if uses a statement journal */
+  bft readOnly:1;         /* True for statements that do not write */
+  bft bIsReader:1;        /* True for statements that read */
+  bft haveEqpOps:1;       /* Bytecode supports EXPLAIN QUERY PLAN */
+  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
+  yDbMask lockMask;       /* Subset of btreeMask that requires a lock */
+  u32 aCounter[9];        /* Counters used by sqlite3_stmt_status() */
+  char *zSql;             /* Text of the SQL statement that generated this */
+#ifdef SQLITE_ENABLE_NORMALIZE
+  char *zNormSql;         /* Normalization of the associated SQL statement */
+  DblquoteStr *pDblStr;   /* List of double-quoted string literals */
+#endif
+  void *pFree;            /* Free this when deleting the vdbe */
+  VdbeFrame *pFrame;      /* Parent frame */
+  VdbeFrame *pDelFrame;   /* List of frame objects to free on VM reset */
+  int nFrame;             /* Number of frames in pFrame list */
+  u32 expmask;            /* Binding to these vars invalidates VM */
+  SubProgram *pProgram;   /* Linked list of all sub-programs used by VM */
+  AuxData *pAuxData;      /* Linked list of auxdata allocations */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int nScan;              /* Entries in aScan[] */
+  ScanStatus *aScan;      /* Scan definitions for sqlite3_stmt_scanstatus() */
+#endif
+};
+
+/*
+** The following are allowed values for Vdbe.eVdbeState
+*/
+#define VDBE_INIT_STATE     0   /* Prepared statement under construction */
+#define VDBE_READY_STATE    1   /* Ready to run but not yet started */
+#define VDBE_RUN_STATE      2   /* Run in progress */
+#define VDBE_HALT_STATE     3   /* Finished.  Need reset() or finalize() */
+
+/*
+** Structure used to store the context required by the
+** sqlite3_preupdate_*() API functions.
+*/
+struct PreUpdate {
+  Vdbe *v;
+  VdbeCursor *pCsr;               /* Cursor to read old values from */
+  int op;                         /* One of SQLITE_INSERT, UPDATE, DELETE */
+  u8 *aRecord;                    /* old.* database record */
+  KeyInfo keyinfo;
+  UnpackedRecord *pUnpacked;      /* Unpacked version of aRecord[] */
+  UnpackedRecord *pNewUnpacked;   /* Unpacked version of new.* record */
+  int iNewReg;                    /* Register for new.* values */
+  int iBlobWrite;                 /* Value returned by preupdate_blobwrite() */
+  i64 iKey1;                      /* First key value passed to hook */
+  i64 iKey2;                      /* Second key value passed to hook */
+  Mem oldipk;                     /* Memory cell holding "old" IPK value */
+  Mem *aNew;                      /* Array of new.* values */
+  Table *pTab;                    /* Schema object being updated */
+  Index *pPk;                     /* PK index if pTab is WITHOUT ROWID */
+  sqlite3_value **apDflt;         /* Array of default values, if required */
+};
+
+/*
+** An instance of this object is used to pass an vector of values into
+** OP_VFilter, the xFilter method of a virtual table.  The vector is the
+** set of values on the right-hand side of an IN constraint.
+**
+** The value as passed into xFilter is an sqlite3_value with a "pointer"
+** type, such as is generated by sqlite3_result_pointer() and read by
+** sqlite3_value_pointer.  Such values have MEM_Term|MEM_Subtype|MEM_Null
+** and a subtype of 'p'.  The sqlite3_vtab_in_first() and _next() interfaces
+** know how to use this object to step through all the values in the
+** right operand of the IN constraint.
+*/
+typedef struct ValueList ValueList;
+struct ValueList {
+  BtCursor *pCsr;          /* An ephemeral table holding all values */
+  sqlite3_value *pOut;     /* Register to hold each decoded output value */
+};
+
+/* Size of content associated with serial types that fit into a
+** single-byte varint.
+*/
+#ifndef SQLITE_AMALGAMATION
+SQLITE_PRIVATE const u8 sqlite3SmallTypeSizes[];
+#endif
+
+/*
+** Function prototypes
+*/
+SQLITE_PRIVATE void sqlite3VdbeError(Vdbe*, const char *, ...);
+SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*);
+SQLITE_PRIVATE void sqlite3VdbeFreeCursorNN(Vdbe*,VdbeCursor*);
+void sqliteVdbePopStack(Vdbe*,int);
+SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeHandleMovedCursor(VdbeCursor *p);
+SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeFinishMoveto(VdbeCursor*);
+SQLITE_PRIVATE int sqlite3VdbeCursorRestore(VdbeCursor*);
+SQLITE_PRIVATE u32 sqlite3VdbeSerialTypeLen(u32);
+SQLITE_PRIVATE u8 sqlite3VdbeOneByteSerialTypeLen(u8);
+#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+SQLITE_PRIVATE   u64 sqlite3FloatSwap(u64 in);
+# define swapMixedEndianFloat(X)  X = sqlite3FloatSwap(X)
+#else
+# define swapMixedEndianFloat(X)
+#endif
+SQLITE_PRIVATE void sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
+SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(sqlite3*, AuxData**, int, int);
+
+int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
+SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(sqlite3*,VdbeCursor*,UnpackedRecord*,int*);
+SQLITE_PRIVATE int sqlite3VdbeIdxRowid(sqlite3*, BtCursor*, i64*);
+SQLITE_PRIVATE int sqlite3VdbeExec(Vdbe*);
+#if !defined(SQLITE_OMIT_EXPLAIN) || defined(SQLITE_ENABLE_BYTECODE_VTAB)
+SQLITE_PRIVATE int sqlite3VdbeNextOpcode(Vdbe*,Mem*,int,int*,int*,Op**);
+SQLITE_PRIVATE char *sqlite3VdbeDisplayP4(sqlite3*,Op*);
+#endif
+#if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS)
+SQLITE_PRIVATE char *sqlite3VdbeDisplayComment(sqlite3*,const Op*,const char*);
+#endif
+#if !defined(SQLITE_OMIT_EXPLAIN)
+SQLITE_PRIVATE int sqlite3VdbeList(Vdbe*);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe*);
+SQLITE_PRIVATE int sqlite3VdbeChangeEncoding(Mem *, int);
+SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem*, const Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
+SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem*, Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemSetStr(Mem*, const char*, i64, u8, void(*)(void*));
+SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem*, i64);
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define sqlite3VdbeMemSetDouble sqlite3VdbeMemSetInt64
+#else
+SQLITE_PRIVATE   void sqlite3VdbeMemSetDouble(Mem*, double);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeMemSetPointer(Mem*, void*, const char*, void(*)(void*));
+SQLITE_PRIVATE void sqlite3VdbeMemInit(Mem*,sqlite3*,u16);
+SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem*);
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem*,int);
+#else
+SQLITE_PRIVATE int sqlite3VdbeMemSetZeroBlob(Mem*,int);
+#endif
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3VdbeMemIsRowSet(const Mem*);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeMemSetRowSet(Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemZeroTerminateIfAble(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem*, u8, u8);
+SQLITE_PRIVATE int sqlite3IntFloatCompare(i64,double);
+SQLITE_PRIVATE i64 sqlite3VdbeIntValue(const Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem*);
+SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeBooleanValue(Mem*, int ifNull);
+SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemCast(Mem*,u8,u8);
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(BtCursor*,u32,u32,Mem*);
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtreeZeroOffset(BtCursor*,u32,Mem*);
+SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p);
+SQLITE_PRIVATE void sqlite3VdbeMemReleaseMalloc(Mem*p);
+SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE int sqlite3VdbeMemAggValue(Mem*, Mem*, FuncDef*);
+#endif
+#if !defined(SQLITE_OMIT_EXPLAIN) || defined(SQLITE_ENABLE_BYTECODE_VTAB)
+SQLITE_PRIVATE const char *sqlite3OpcodeName(int);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
+SQLITE_PRIVATE int sqlite3VdbeMemClearAndResize(Mem *pMem, int n);
+SQLITE_PRIVATE int sqlite3VdbeCloseStatement(Vdbe *, int);
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3VdbeFrameIsValid(VdbeFrame*);
+#endif
+SQLITE_PRIVATE void sqlite3VdbeFrameMemDel(void*);      /* Destructor on Mem */
+SQLITE_PRIVATE void sqlite3VdbeFrameDelete(VdbeFrame*); /* Actually deletes the Frame */
+SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *);
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+SQLITE_PRIVATE void sqlite3VdbePreUpdateHook(
+    Vdbe*,VdbeCursor*,int,const char*,Table*,i64,int,int);
+#endif
+SQLITE_PRIVATE int sqlite3VdbeTransferError(Vdbe *p);
+
+SQLITE_PRIVATE int sqlite3VdbeSorterInit(sqlite3 *, int, VdbeCursor *);
+SQLITE_PRIVATE void sqlite3VdbeSorterReset(sqlite3 *, VdbeSorter *);
+SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *, VdbeCursor *);
+SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(const VdbeCursor *, Mem *);
+SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *, const VdbeCursor *);
+SQLITE_PRIVATE int sqlite3VdbeSorterRewind(const VdbeCursor *, int *);
+SQLITE_PRIVATE int sqlite3VdbeSorterWrite(const VdbeCursor *, Mem *);
+SQLITE_PRIVATE int sqlite3VdbeSorterCompare(const VdbeCursor *, Mem *, int, int *);
+
+SQLITE_PRIVATE void sqlite3VdbeValueListFree(void*);
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3VdbeIncrWriteCounter(Vdbe*, VdbeCursor*);
+SQLITE_PRIVATE   void sqlite3VdbeAssertAbortable(Vdbe*);
+#else
+# define sqlite3VdbeIncrWriteCounter(V,C)
+# define sqlite3VdbeAssertAbortable(V)
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE)
+SQLITE_PRIVATE   void sqlite3VdbeEnter(Vdbe*);
+#else
+# define sqlite3VdbeEnter(X)
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0
+SQLITE_PRIVATE   void sqlite3VdbeLeave(Vdbe*);
+#else
+# define sqlite3VdbeLeave(X)
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE void sqlite3VdbeMemAboutToChange(Vdbe*,Mem*);
+SQLITE_PRIVATE int sqlite3VdbeCheckMemInvariants(Mem*);
+#endif
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+SQLITE_PRIVATE int sqlite3VdbeCheckFk(Vdbe *, int);
+#else
+# define sqlite3VdbeCheckFk(p,i) 0
+#endif
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE   void sqlite3VdbePrintSql(Vdbe*);
+SQLITE_PRIVATE   void sqlite3VdbeMemPrettyPrint(Mem *pMem, StrAccum *pStr);
+#endif
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_PRIVATE   int sqlite3VdbeMemTranslate(Mem*, u8);
+SQLITE_PRIVATE   int sqlite3VdbeMemHandleBom(Mem *pMem);
+#endif
+
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE   int sqlite3VdbeMemExpandBlob(Mem *);
+  #define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
+#else
+  #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
+  #define ExpandBlob(P) SQLITE_OK
+#endif
+
+#endif /* !defined(SQLITE_VDBEINT_H) */
+
+/************** End of vdbeInt.h *********************************************/
+/************** Continuing where we left off in status.c *********************/
+
+/*
+** Variables in which to record status information.
+*/
+#if SQLITE_PTRSIZE>4
+typedef sqlite3_int64 sqlite3StatValueType;
+#else
+typedef u32 sqlite3StatValueType;
+#endif
+typedef struct sqlite3StatType sqlite3StatType;
+static SQLITE_WSD struct sqlite3StatType {
+  sqlite3StatValueType nowValue[10];  /* Current value */
+  sqlite3StatValueType mxValue[10];   /* Maximum value */
+} sqlite3Stat = { {0,}, {0,} };
+
+/*
+** Elements of sqlite3Stat[] are protected by either the memory allocator
+** mutex, or by the pcache1 mutex.  The following array determines which.
+*/
+static const char statMutex[] = {
+  0,  /* SQLITE_STATUS_MEMORY_USED */
+  1,  /* SQLITE_STATUS_PAGECACHE_USED */
+  1,  /* SQLITE_STATUS_PAGECACHE_OVERFLOW */
+  0,  /* SQLITE_STATUS_SCRATCH_USED */
+  0,  /* SQLITE_STATUS_SCRATCH_OVERFLOW */
+  0,  /* SQLITE_STATUS_MALLOC_SIZE */
+  0,  /* SQLITE_STATUS_PARSER_STACK */
+  1,  /* SQLITE_STATUS_PAGECACHE_SIZE */
+  0,  /* SQLITE_STATUS_SCRATCH_SIZE */
+  0,  /* SQLITE_STATUS_MALLOC_COUNT */
+};
+
+
+/* The "wsdStat" macro will resolve to the status information
+** state vector.  If writable static data is unsupported on the target,
+** we have to locate the state vector at run-time.  In the more common
+** case where writable static data is supported, wsdStat can refer directly
+** to the "sqlite3Stat" state vector declared above.
+*/
+#ifdef SQLITE_OMIT_WSD
+# define wsdStatInit  sqlite3StatType *x = &GLOBAL(sqlite3StatType,sqlite3Stat)
+# define wsdStat x[0]
+#else
+# define wsdStatInit
+# define wsdStat sqlite3Stat
+#endif
+
+/*
+** Return the current value of a status parameter.  The caller must
+** be holding the appropriate mutex.
+*/
+SQLITE_PRIVATE sqlite3_int64 sqlite3StatusValue(int op){
+  wsdStatInit;
+  assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
+  assert( op>=0 && op<ArraySize(statMutex) );
+  assert( sqlite3_mutex_held(statMutex[op] ? sqlite3Pcache1Mutex()
+                                           : sqlite3MallocMutex()) );
+  return wsdStat.nowValue[op];
+}
+
+/*
+** Add N to the value of a status record.  The caller must hold the
+** appropriate mutex.  (Locking is checked by assert()).
+**
+** The StatusUp() routine can accept positive or negative values for N.
+** The value of N is added to the current status value and the high-water
+** mark is adjusted if necessary.
+**
+** The StatusDown() routine lowers the current value by N.  The highwater
+** mark is unchanged.  N must be non-negative for StatusDown().
+*/
+SQLITE_PRIVATE void sqlite3StatusUp(int op, int N){
+  wsdStatInit;
+  assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
+  assert( op>=0 && op<ArraySize(statMutex) );
+  assert( sqlite3_mutex_held(statMutex[op] ? sqlite3Pcache1Mutex()
+                                           : sqlite3MallocMutex()) );
+  wsdStat.nowValue[op] += N;
+  if( wsdStat.nowValue[op]>wsdStat.mxValue[op] ){
+    wsdStat.mxValue[op] = wsdStat.nowValue[op];
+  }
+}
+SQLITE_PRIVATE void sqlite3StatusDown(int op, int N){
+  wsdStatInit;
+  assert( N>=0 );
+  assert( op>=0 && op<ArraySize(statMutex) );
+  assert( sqlite3_mutex_held(statMutex[op] ? sqlite3Pcache1Mutex()
+                                           : sqlite3MallocMutex()) );
+  assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
+  wsdStat.nowValue[op] -= N;
+}
+
+/*
+** Adjust the highwater mark if necessary.
+** The caller must hold the appropriate mutex.
+*/
+SQLITE_PRIVATE void sqlite3StatusHighwater(int op, int X){
+  sqlite3StatValueType newValue;
+  wsdStatInit;
+  assert( X>=0 );
+  newValue = (sqlite3StatValueType)X;
+  assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
+  assert( op>=0 && op<ArraySize(statMutex) );
+  assert( sqlite3_mutex_held(statMutex[op] ? sqlite3Pcache1Mutex()
+                                           : sqlite3MallocMutex()) );
+  assert( op==SQLITE_STATUS_MALLOC_SIZE
+          || op==SQLITE_STATUS_PAGECACHE_SIZE
+          || op==SQLITE_STATUS_PARSER_STACK );
+  if( newValue>wsdStat.mxValue[op] ){
+    wsdStat.mxValue[op] = newValue;
+  }
+}
+
+/*
+** Query status information.
+*/
+SQLITE_API int sqlite3_status64(
+  int op,
+  sqlite3_int64 *pCurrent,
+  sqlite3_int64 *pHighwater,
+  int resetFlag
+){
+  sqlite3_mutex *pMutex;
+  wsdStatInit;
+  if( op<0 || op>=ArraySize(wsdStat.nowValue) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCurrent==0 || pHighwater==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  pMutex = statMutex[op] ? sqlite3Pcache1Mutex() : sqlite3MallocMutex();
+  sqlite3_mutex_enter(pMutex);
+  *pCurrent = wsdStat.nowValue[op];
+  *pHighwater = wsdStat.mxValue[op];
+  if( resetFlag ){
+    wsdStat.mxValue[op] = wsdStat.nowValue[op];
+  }
+  sqlite3_mutex_leave(pMutex);
+  (void)pMutex;  /* Prevent warning when SQLITE_THREADSAFE=0 */
+  return SQLITE_OK;
+}
+SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag){
+  sqlite3_int64 iCur = 0, iHwtr = 0;
+  int rc;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCurrent==0 || pHighwater==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  rc = sqlite3_status64(op, &iCur, &iHwtr, resetFlag);
+  if( rc==0 ){
+    *pCurrent = (int)iCur;
+    *pHighwater = (int)iHwtr;
+  }
+  return rc;
+}
+
+/*
+** Return the number of LookasideSlot elements on the linked list
+*/
+static u32 countLookasideSlots(LookasideSlot *p){
+  u32 cnt = 0;
+  while( p ){
+    p = p->pNext;
+    cnt++;
+  }
+  return cnt;
+}
+
+/*
+** Count the number of slots of lookaside memory that are outstanding
+*/
+SQLITE_PRIVATE int sqlite3LookasideUsed(sqlite3 *db, int *pHighwater){
+  u32 nInit = countLookasideSlots(db->lookaside.pInit);
+  u32 nFree = countLookasideSlots(db->lookaside.pFree);
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  nInit += countLookasideSlots(db->lookaside.pSmallInit);
+  nFree += countLookasideSlots(db->lookaside.pSmallFree);
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+  if( pHighwater ) *pHighwater = db->lookaside.nSlot - nInit;
+  return db->lookaside.nSlot - (nInit+nFree);
+}
+
+/*
+** Query status information for a single database connection
+*/
+SQLITE_API int sqlite3_db_status(
+  sqlite3 *db,          /* The database connection whose status is desired */
+  int op,               /* Status verb */
+  int *pCurrent,        /* Write current value here */
+  int *pHighwater,      /* Write high-water mark here */
+  int resetFlag         /* Reset high-water mark if true */
+){
+  int rc = SQLITE_OK;   /* Return code */
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || pCurrent==0|| pHighwater==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  switch( op ){
+    case SQLITE_DBSTATUS_LOOKASIDE_USED: {
+      *pCurrent = sqlite3LookasideUsed(db, pHighwater);
+      if( resetFlag ){
+        LookasideSlot *p = db->lookaside.pFree;
+        if( p ){
+          while( p->pNext ) p = p->pNext;
+          p->pNext = db->lookaside.pInit;
+          db->lookaside.pInit = db->lookaside.pFree;
+          db->lookaside.pFree = 0;
+        }
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+        p = db->lookaside.pSmallFree;
+        if( p ){
+          while( p->pNext ) p = p->pNext;
+          p->pNext = db->lookaside.pSmallInit;
+          db->lookaside.pSmallInit = db->lookaside.pSmallFree;
+          db->lookaside.pSmallFree = 0;
+        }
+#endif
+      }
+      break;
+    }
+
+    case SQLITE_DBSTATUS_LOOKASIDE_HIT:
+    case SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE:
+    case SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL: {
+      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_HIT );
+      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE );
+      testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL );
+      assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)>=0 );
+      assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)<3 );
+      *pCurrent = 0;
+      *pHighwater = db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT];
+      if( resetFlag ){
+        db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT] = 0;
+      }
+      break;
+    }
+
+    /*
+    ** Return an approximation for the amount of memory currently used
+    ** by all pagers associated with the given database connection.  The
+    ** highwater mark is meaningless and is returned as zero.
+    */
+    case SQLITE_DBSTATUS_CACHE_USED_SHARED:
+    case SQLITE_DBSTATUS_CACHE_USED: {
+      int totalUsed = 0;
+      int i;
+      sqlite3BtreeEnterAll(db);
+      for(i=0; i<db->nDb; i++){
+        Btree *pBt = db->aDb[i].pBt;
+        if( pBt ){
+          Pager *pPager = sqlite3BtreePager(pBt);
+          int nByte = sqlite3PagerMemUsed(pPager);
+          if( op==SQLITE_DBSTATUS_CACHE_USED_SHARED ){
+            nByte = nByte / sqlite3BtreeConnectionCount(pBt);
+          }
+          totalUsed += nByte;
+        }
+      }
+      sqlite3BtreeLeaveAll(db);
+      *pCurrent = totalUsed;
+      *pHighwater = 0;
+      break;
+    }
+
+    /*
+    ** *pCurrent gets an accurate estimate of the amount of memory used
+    ** to store the schema for all databases (main, temp, and any ATTACHed
+    ** databases.  *pHighwater is set to zero.
+    */
+    case SQLITE_DBSTATUS_SCHEMA_USED: {
+      int i;                      /* Used to iterate through schemas */
+      int nByte = 0;              /* Used to accumulate return value */
+
+      sqlite3BtreeEnterAll(db);
+      db->pnBytesFreed = &nByte;
+      assert( db->lookaside.pEnd==db->lookaside.pTrueEnd );
+      db->lookaside.pEnd = db->lookaside.pStart;
+      for(i=0; i<db->nDb; i++){
+        Schema *pSchema = db->aDb[i].pSchema;
+        if( ALWAYS(pSchema!=0) ){
+          HashElem *p;
+
+          nByte += sqlite3GlobalConfig.m.xRoundup(sizeof(HashElem)) * (
+              pSchema->tblHash.count
+            + pSchema->trigHash.count
+            + pSchema->idxHash.count
+            + pSchema->fkeyHash.count
+          );
+          nByte += sqlite3_msize(pSchema->tblHash.ht);
+          nByte += sqlite3_msize(pSchema->trigHash.ht);
+          nByte += sqlite3_msize(pSchema->idxHash.ht);
+          nByte += sqlite3_msize(pSchema->fkeyHash.ht);
+
+          for(p=sqliteHashFirst(&pSchema->trigHash); p; p=sqliteHashNext(p)){
+            sqlite3DeleteTrigger(db, (Trigger*)sqliteHashData(p));
+          }
+          for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
+            sqlite3DeleteTable(db, (Table *)sqliteHashData(p));
+          }
+        }
+      }
+      db->pnBytesFreed = 0;
+      db->lookaside.pEnd = db->lookaside.pTrueEnd;
+      sqlite3BtreeLeaveAll(db);
+
+      *pHighwater = 0;
+      *pCurrent = nByte;
+      break;
+    }
+
+    /*
+    ** *pCurrent gets an accurate estimate of the amount of memory used
+    ** to store all prepared statements.
+    ** *pHighwater is set to zero.
+    */
+    case SQLITE_DBSTATUS_STMT_USED: {
+      struct Vdbe *pVdbe;         /* Used to iterate through VMs */
+      int nByte = 0;              /* Used to accumulate return value */
+
+      db->pnBytesFreed = &nByte;
+      assert( db->lookaside.pEnd==db->lookaside.pTrueEnd );
+      db->lookaside.pEnd = db->lookaside.pStart;
+      for(pVdbe=db->pVdbe; pVdbe; pVdbe=pVdbe->pVNext){
+        sqlite3VdbeDelete(pVdbe);
+      }
+      db->lookaside.pEnd = db->lookaside.pTrueEnd;
+      db->pnBytesFreed = 0;
+
+      *pHighwater = 0;  /* IMP: R-64479-57858 */
+      *pCurrent = nByte;
+
+      break;
+    }
+
+    /*
+    ** Set *pCurrent to the total cache hits or misses encountered by all
+    ** pagers the database handle is connected to. *pHighwater is always set
+    ** to zero.
+    */
+    case SQLITE_DBSTATUS_CACHE_SPILL:
+      op = SQLITE_DBSTATUS_CACHE_WRITE+1;
+      /* no break */ deliberate_fall_through
+    case SQLITE_DBSTATUS_CACHE_HIT:
+    case SQLITE_DBSTATUS_CACHE_MISS:
+    case SQLITE_DBSTATUS_CACHE_WRITE:{
+      int i;
+      u64 nRet = 0;
+      assert( SQLITE_DBSTATUS_CACHE_MISS==SQLITE_DBSTATUS_CACHE_HIT+1 );
+      assert( SQLITE_DBSTATUS_CACHE_WRITE==SQLITE_DBSTATUS_CACHE_HIT+2 );
+
+      for(i=0; i<db->nDb; i++){
+        if( db->aDb[i].pBt ){
+          Pager *pPager = sqlite3BtreePager(db->aDb[i].pBt);
+          sqlite3PagerCacheStat(pPager, op, resetFlag, &nRet);
+        }
+      }
+      *pHighwater = 0; /* IMP: R-42420-56072 */
+                       /* IMP: R-54100-20147 */
+                       /* IMP: R-29431-39229 */
+      *pCurrent = (int)nRet & 0x7fffffff;
+      break;
+    }
+
+    /* Set *pCurrent to non-zero if there are unresolved deferred foreign
+    ** key constraints.  Set *pCurrent to zero if all foreign key constraints
+    ** have been satisfied.  The *pHighwater is always set to zero.
+    */
+    case SQLITE_DBSTATUS_DEFERRED_FKS: {
+      *pHighwater = 0;  /* IMP: R-11967-56545 */
+      *pCurrent = db->nDeferredImmCons>0 || db->nDeferredCons>0;
+      break;
+    }
+
+    default: {
+      rc = SQLITE_ERROR;
+    }
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/************** End of status.c **********************************************/
+/************** Begin file date.c ********************************************/
+/*
+** 2003 October 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement date and time
+** functions for SQLite.
+**
+** There is only one exported symbol in this file - the function
+** sqlite3RegisterDateTimeFunctions() found at the bottom of the file.
+** All other code has file scope.
+**
+** SQLite processes all times and dates as julian day numbers.  The
+** dates and times are stored as the number of days since noon
+** in Greenwich on November 24, 4714 B.C. according to the Gregorian
+** calendar system.
+**
+** 1970-01-01 00:00:00 is JD 2440587.5
+** 2000-01-01 00:00:00 is JD 2451544.5
+**
+** This implementation requires years to be expressed as a 4-digit number
+** which means that only dates between 0000-01-01 and 9999-12-31 can
+** be represented, even though julian day numbers allow a much wider
+** range of dates.
+**
+** The Gregorian calendar system is used for all dates and times,
+** even those that predate the Gregorian calendar.  Historians usually
+** use the julian calendar for dates prior to 1582-10-15 and for some
+** dates afterwards, depending on locale.  Beware of this difference.
+**
+** The conversion algorithms are implemented based on descriptions
+** in the following text:
+**
+**      Jean Meeus
+**      Astronomical Algorithms, 2nd Edition, 1998
+**      ISBN 0-943396-61-1
+**      Willmann-Bell, Inc
+**      Richmond, Virginia (USA)
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdlib.h> */
+/* #include <assert.h> */
+#include <time.h>
+
+#ifndef SQLITE_OMIT_DATETIME_FUNCS
+
+/*
+** The MSVC CRT on Windows CE may not have a localtime() function.
+** So declare a substitute.  The substitute function itself is
+** defined in "os_win.c".
+*/
+#if !defined(SQLITE_OMIT_LOCALTIME) && defined(_WIN32_WCE) && \
+    (!defined(SQLITE_MSVC_LOCALTIME_API) || !SQLITE_MSVC_LOCALTIME_API)
+struct tm *__cdecl localtime(const time_t *);
+#endif
+
+/*
+** A structure for holding a single date and time.
+*/
+typedef struct DateTime DateTime;
+struct DateTime {
+  sqlite3_int64 iJD;  /* The julian day number times 86400000 */
+  int Y, M, D;        /* Year, month, and day */
+  int h, m;           /* Hour and minutes */
+  int tz;             /* Timezone offset in minutes */
+  double s;           /* Seconds */
+  char validJD;       /* True (1) if iJD is valid */
+  char validYMD;      /* True (1) if Y,M,D are valid */
+  char validHMS;      /* True (1) if h,m,s are valid */
+  char nFloor;            /* Days to implement "floor" */
+  unsigned rawS      : 1; /* Raw numeric value stored in s */
+  unsigned isError   : 1; /* An overflow has occurred */
+  unsigned useSubsec : 1; /* Display subsecond precision */
+  unsigned isUtc     : 1; /* Time is known to be UTC */
+  unsigned isLocal   : 1; /* Time is known to be localtime */
+};
+
+
+/*
+** Convert zDate into one or more integers according to the conversion
+** specifier zFormat.
+**
+** zFormat[] contains 4 characters for each integer converted, except for
+** the last integer which is specified by three characters.  The meaning
+** of a four-character format specifiers ABCD is:
+**
+**    A:   number of digits to convert.  Always "2" or "4".
+**    B:   minimum value.  Always "0" or "1".
+**    C:   maximum value, decoded as:
+**           a:  12
+**           b:  14
+**           c:  24
+**           d:  31
+**           e:  59
+**           f:  9999
+**    D:   the separator character, or \000 to indicate this is the
+**         last number to convert.
+**
+** Example:  To translate an ISO-8601 date YYYY-MM-DD, the format would
+** be "40f-21a-20c".  The "40f-" indicates the 4-digit year followed by "-".
+** The "21a-" indicates the 2-digit month followed by "-".  The "20c" indicates
+** the 2-digit day which is the last integer in the set.
+**
+** The function returns the number of successful conversions.
+*/
+static int getDigits(const char *zDate, const char *zFormat, ...){
+  /* The aMx[] array translates the 3rd character of each format
+  ** spec into a max size:    a   b   c   d   e      f */
+  static const u16 aMx[] = { 12, 14, 24, 31, 59, 14712 };
+  va_list ap;
+  int cnt = 0;
+  char nextC;
+  va_start(ap, zFormat);
+  do{
+    char N = zFormat[0] - '0';
+    char min = zFormat[1] - '0';
+    int val = 0;
+    u16 max;
+
+    assert( zFormat[2]>='a' && zFormat[2]<='f' );
+    max = aMx[zFormat[2] - 'a'];
+    nextC = zFormat[3];
+    val = 0;
+    while( N-- ){
+      if( !sqlite3Isdigit(*zDate) ){
+        goto end_getDigits;
+      }
+      val = val*10 + *zDate - '0';
+      zDate++;
+    }
+    if( val<(int)min || val>(int)max || (nextC!=0 && nextC!=*zDate) ){
+      goto end_getDigits;
+    }
+    *va_arg(ap,int*) = val;
+    zDate++;
+    cnt++;
+    zFormat += 4;
+  }while( nextC );
+end_getDigits:
+  va_end(ap);
+  return cnt;
+}
+
+/*
+** Parse a timezone extension on the end of a date-time.
+** The extension is of the form:
+**
+**        (+/-)HH:MM
+**
+** Or the "zulu" notation:
+**
+**        Z
+**
+** If the parse is successful, write the number of minutes
+** of change in p->tz and return 0.  If a parser error occurs,
+** return non-zero.
+**
+** A missing specifier is not considered an error.
+*/
+static int parseTimezone(const char *zDate, DateTime *p){
+  int sgn = 0;
+  int nHr, nMn;
+  int c;
+  while( sqlite3Isspace(*zDate) ){ zDate++; }
+  p->tz = 0;
+  c = *zDate;
+  if( c=='-' ){
+    sgn = -1;
+  }else if( c=='+' ){
+    sgn = +1;
+  }else if( c=='Z' || c=='z' ){
+    zDate++;
+    p->isLocal = 0;
+    p->isUtc = 1;
+    goto zulu_time;
+  }else{
+    return c!=0;
+  }
+  zDate++;
+  if( getDigits(zDate, "20b:20e", &nHr, &nMn)!=2 ){
+    return 1;
+  }
+  zDate += 5;
+  p->tz = sgn*(nMn + nHr*60);
+zulu_time:
+  while( sqlite3Isspace(*zDate) ){ zDate++; }
+  return *zDate!=0;
+}
+
+/*
+** Parse times of the form HH:MM or HH:MM:SS or HH:MM:SS.FFFF.
+** The HH, MM, and SS must each be exactly 2 digits.  The
+** fractional seconds FFFF can be one or more digits.
+**
+** Return 1 if there is a parsing error and 0 on success.
+*/
+static int parseHhMmSs(const char *zDate, DateTime *p){
+  int h, m, s;
+  double ms = 0.0;
+  if( getDigits(zDate, "20c:20e", &h, &m)!=2 ){
+    return 1;
+  }
+  zDate += 5;
+  if( *zDate==':' ){
+    zDate++;
+    if( getDigits(zDate, "20e", &s)!=1 ){
+      return 1;
+    }
+    zDate += 2;
+    if( *zDate=='.' && sqlite3Isdigit(zDate[1]) ){
+      double rScale = 1.0;
+      zDate++;
+      while( sqlite3Isdigit(*zDate) ){
+        ms = ms*10.0 + *zDate - '0';
+        rScale *= 10.0;
+        zDate++;
+      }
+      ms /= rScale;
+      /* Truncate to avoid problems with sub-milliseconds
+      ** rounding. https://sqlite.org/forum/forumpost/766a2c9231 */
+      if( ms>0.999 ) ms = 0.999;
+    }
+  }else{
+    s = 0;
+  }
+  p->validJD = 0;
+  p->rawS = 0;
+  p->validHMS = 1;
+  p->h = h;
+  p->m = m;
+  p->s = s + ms;
+  if( parseTimezone(zDate, p) ) return 1;
+  return 0;
+}
+
+/*
+** Put the DateTime object into its error state.
+*/
+static void datetimeError(DateTime *p){
+  memset(p, 0, sizeof(*p));
+  p->isError = 1;
+}
+
+/*
+** Convert from YYYY-MM-DD HH:MM:SS to julian day.  We always assume
+** that the YYYY-MM-DD is according to the Gregorian calendar.
+**
+** Reference:  Meeus page 61
+*/
+static void computeJD(DateTime *p){
+  int Y, M, D, A, B, X1, X2;
+
+  if( p->validJD ) return;
+  if( p->validYMD ){
+    Y = p->Y;
+    M = p->M;
+    D = p->D;
+  }else{
+    Y = 2000;  /* If no YMD specified, assume 2000-Jan-01 */
+    M = 1;
+    D = 1;
+  }
+  if( Y<-4713 || Y>9999 || p->rawS ){
+    datetimeError(p);
+    return;
+  }
+  if( M<=2 ){
+    Y--;
+    M += 12;
+  }
+  A = (Y+4800)/100;
+  B = 38 - A + (A/4);
+  X1 = 36525*(Y+4716)/100;
+  X2 = 306001*(M+1)/10000;
+  p->iJD = (sqlite3_int64)((X1 + X2 + D + B - 1524.5 ) * 86400000);
+  p->validJD = 1;
+  if( p->validHMS ){
+    p->iJD += p->h*3600000 + p->m*60000 + (sqlite3_int64)(p->s*1000 + 0.5);
+    if( p->tz ){
+      p->iJD -= p->tz*60000;
+      p->validYMD = 0;
+      p->validHMS = 0;
+      p->tz = 0;
+      p->isUtc = 1;
+      p->isLocal = 0;
+    }
+  }
+}
+
+/*
+** Given the YYYY-MM-DD information current in p, determine if there
+** is day-of-month overflow and set nFloor to the number of days that
+** would need to be subtracted from the date in order to bring the
+** date back to the end of the month.
+*/
+static void computeFloor(DateTime *p){
+  assert( p->validYMD || p->isError );
+  assert( p->D>=0 && p->D<=31 );
+  assert( p->M>=0 && p->M<=12 );
+  if( p->D<=28 ){
+    p->nFloor = 0;
+  }else if( (1<<p->M) & 0x15aa ){
+    p->nFloor = 0;
+  }else if( p->M!=2 ){
+    p->nFloor = (p->D==31);
+  }else if( p->Y%4!=0 || (p->Y%100==0 && p->Y%400!=0) ){
+    p->nFloor = p->D - 28;
+  }else{
+    p->nFloor = p->D - 29;
+  }
+}
+
+/*
+** Parse dates of the form
+**
+**     YYYY-MM-DD HH:MM:SS.FFF
+**     YYYY-MM-DD HH:MM:SS
+**     YYYY-MM-DD HH:MM
+**     YYYY-MM-DD
+**
+** Write the result into the DateTime structure and return 0
+** on success and 1 if the input string is not a well-formed
+** date.
+*/
+static int parseYyyyMmDd(const char *zDate, DateTime *p){
+  int Y, M, D, neg;
+
+  if( zDate[0]=='-' ){
+    zDate++;
+    neg = 1;
+  }else{
+    neg = 0;
+  }
+  if( getDigits(zDate, "40f-21a-21d", &Y, &M, &D)!=3 ){
+    return 1;
+  }
+  zDate += 10;
+  while( sqlite3Isspace(*zDate) || 'T'==*(u8*)zDate ){ zDate++; }
+  if( parseHhMmSs(zDate, p)==0 ){
+    /* We got the time */
+  }else if( *zDate==0 ){
+    p->validHMS = 0;
+  }else{
+    return 1;
+  }
+  p->validJD = 0;
+  p->validYMD = 1;
+  p->Y = neg ? -Y : Y;
+  p->M = M;
+  p->D = D;
+  computeFloor(p);
+  if( p->tz ){
+    computeJD(p);
+  }
+  return 0;
+}
+
+
+static void clearYMD_HMS_TZ(DateTime *p);  /* Forward declaration */
+
+/*
+** Set the time to the current time reported by the VFS.
+**
+** Return the number of errors.
+*/
+static int setDateTimeToCurrent(sqlite3_context *context, DateTime *p){
+  p->iJD = sqlite3StmtCurrentTime(context);
+  if( p->iJD>0 ){
+    p->validJD = 1;
+    p->isUtc = 1;
+    p->isLocal = 0;
+    clearYMD_HMS_TZ(p);
+    return 0;
+  }else{
+    return 1;
+  }
+}
+
+/*
+** Input "r" is a numeric quantity which might be a julian day number,
+** or the number of seconds since 1970.  If the value if r is within
+** range of a julian day number, install it as such and set validJD.
+** If the value is a valid unix timestamp, put it in p->s and set p->rawS.
+*/
+static void setRawDateNumber(DateTime *p, double r){
+  p->s = r;
+  p->rawS = 1;
+  if( r>=0.0 && r<5373484.5 ){
+    p->iJD = (sqlite3_int64)(r*86400000.0 + 0.5);
+    p->validJD = 1;
+  }
+}
+
+/*
+** Attempt to parse the given string into a julian day number.  Return
+** the number of errors.
+**
+** The following are acceptable forms for the input string:
+**
+**      YYYY-MM-DD HH:MM:SS.FFF  +/-HH:MM
+**      DDDD.DD
+**      now
+**
+** In the first form, the +/-HH:MM is always optional.  The fractional
+** seconds extension (the ".FFF") is optional.  The seconds portion
+** (":SS.FFF") is option.  The year and date can be omitted as long
+** as there is a time string.  The time string can be omitted as long
+** as there is a year and date.
+*/
+static int parseDateOrTime(
+  sqlite3_context *context,
+  const char *zDate,
+  DateTime *p
+){
+  double r;
+  if( parseYyyyMmDd(zDate,p)==0 ){
+    return 0;
+  }else if( parseHhMmSs(zDate, p)==0 ){
+    return 0;
+  }else if( sqlite3StrICmp(zDate,"now")==0 && sqlite3NotPureFunc(context) ){
+    return setDateTimeToCurrent(context, p);
+  }else if( sqlite3AtoF(zDate, &r, sqlite3Strlen30(zDate), SQLITE_UTF8)>0 ){
+    setRawDateNumber(p, r);
+    return 0;
+  }else if( (sqlite3StrICmp(zDate,"subsec")==0
+             || sqlite3StrICmp(zDate,"subsecond")==0)
+           && sqlite3NotPureFunc(context) ){
+    p->useSubsec = 1;
+    return setDateTimeToCurrent(context, p);
+  }
+  return 1;
+}
+
+/* The julian day number for 9999-12-31 23:59:59.999 is 5373484.4999999.
+** Multiplying this by 86400000 gives 464269060799999 as the maximum value
+** for DateTime.iJD.
+**
+** But some older compilers (ex: gcc 4.2.1 on older Macs) cannot deal with
+** such a large integer literal, so we have to encode it.
+*/
+#define INT_464269060799999  ((((i64)0x1a640)<<32)|0x1072fdff)
+
+/*
+** Return TRUE if the given julian day number is within range.
+**
+** The input is the JulianDay times 86400000.
+*/
+static int validJulianDay(sqlite3_int64 iJD){
+  return iJD>=0 && iJD<=INT_464269060799999;
+}
+
+/*
+** Compute the Year, Month, and Day from the julian day number.
+*/
+static void computeYMD(DateTime *p){
+  int Z, alpha, A, B, C, D, E, X1;
+  if( p->validYMD ) return;
+  if( !p->validJD ){
+    p->Y = 2000;
+    p->M = 1;
+    p->D = 1;
+  }else if( !validJulianDay(p->iJD) ){
+    datetimeError(p);
+    return;
+  }else{
+    Z = (int)((p->iJD + 43200000)/86400000);
+    alpha = (int)((Z + 32044.75)/36524.25) - 52;
+    A = Z + 1 + alpha - ((alpha+100)/4) + 25;
+    B = A + 1524;
+    C = (int)((B - 122.1)/365.25);
+    D = (36525*(C&32767))/100;
+    E = (int)((B-D)/30.6001);
+    X1 = (int)(30.6001*E);
+    p->D = B - D - X1;
+    p->M = E<14 ? E-1 : E-13;
+    p->Y = p->M>2 ? C - 4716 : C - 4715;
+  }
+  p->validYMD = 1;
+}
+
+/*
+** Compute the Hour, Minute, and Seconds from the julian day number.
+*/
+static void computeHMS(DateTime *p){
+  int day_ms, day_min; /* milliseconds, minutes into the day */
+  if( p->validHMS ) return;
+  computeJD(p);
+  day_ms = (int)((p->iJD + 43200000) % 86400000);
+  p->s = (day_ms % 60000)/1000.0;
+  day_min = day_ms/60000;
+  p->m = day_min % 60;
+  p->h = day_min / 60;
+  p->rawS = 0;
+  p->validHMS = 1;
+}
+
+/*
+** Compute both YMD and HMS
+*/
+static void computeYMD_HMS(DateTime *p){
+  computeYMD(p);
+  computeHMS(p);
+}
+
+/*
+** Clear the YMD and HMS and the TZ
+*/
+static void clearYMD_HMS_TZ(DateTime *p){
+  p->validYMD = 0;
+  p->validHMS = 0;
+  p->tz = 0;
+}
+
+#ifndef SQLITE_OMIT_LOCALTIME
+/*
+** On recent Windows platforms, the localtime_s() function is available
+** as part of the "Secure CRT". It is essentially equivalent to
+** localtime_r() available under most POSIX platforms, except that the
+** order of the parameters is reversed.
+**
+** See http://msdn.microsoft.com/en-us/library/a442x3ye(VS.80).aspx.
+**
+** If the user has not indicated to use localtime_r() or localtime_s()
+** already, check for an MSVC build environment that provides
+** localtime_s().
+*/
+#if !HAVE_LOCALTIME_R && !HAVE_LOCALTIME_S \
+    && defined(_MSC_VER) && defined(_CRT_INSECURE_DEPRECATE)
+#undef  HAVE_LOCALTIME_S
+#define HAVE_LOCALTIME_S 1
+#endif
+
+/*
+** The following routine implements the rough equivalent of localtime_r()
+** using whatever operating-system specific localtime facility that
+** is available.  This routine returns 0 on success and
+** non-zero on any kind of error.
+**
+** If the sqlite3GlobalConfig.bLocaltimeFault variable is non-zero then this
+** routine will always fail.  If bLocaltimeFault is nonzero and
+** sqlite3GlobalConfig.xAltLocaltime is not NULL, then xAltLocaltime() is
+** invoked in place of the OS-defined localtime() function.
+**
+** EVIDENCE-OF: R-62172-00036 In this implementation, the standard C
+** library function localtime_r() is used to assist in the calculation of
+** local time.
+*/
+static int osLocaltime(time_t *t, struct tm *pTm){
+  int rc;
+#if !HAVE_LOCALTIME_R && !HAVE_LOCALTIME_S
+  struct tm *pX;
+#if SQLITE_THREADSAFE>0
+  sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+  sqlite3_mutex_enter(mutex);
+  pX = localtime(t);
+#ifndef SQLITE_UNTESTABLE
+  if( sqlite3GlobalConfig.bLocaltimeFault ){
+    if( sqlite3GlobalConfig.xAltLocaltime!=0
+     && 0==sqlite3GlobalConfig.xAltLocaltime((const void*)t,(void*)pTm)
+    ){
+      pX = pTm;
+    }else{
+      pX = 0;
+    }
+  }
+#endif
+  if( pX ) *pTm = *pX;
+#if SQLITE_THREADSAFE>0
+  sqlite3_mutex_leave(mutex);
+#endif
+  rc = pX==0;
+#else
+#ifndef SQLITE_UNTESTABLE
+  if( sqlite3GlobalConfig.bLocaltimeFault ){
+    if( sqlite3GlobalConfig.xAltLocaltime!=0 ){
+      return sqlite3GlobalConfig.xAltLocaltime((const void*)t,(void*)pTm);
+    }else{
+      return 1;
+    }
+  }
+#endif
+#if HAVE_LOCALTIME_R
+  rc = localtime_r(t, pTm)==0;
+#else
+  rc = localtime_s(pTm, t);
+#endif /* HAVE_LOCALTIME_R */
+#endif /* HAVE_LOCALTIME_R || HAVE_LOCALTIME_S */
+  return rc;
+}
+#endif /* SQLITE_OMIT_LOCALTIME */
+
+
+#ifndef SQLITE_OMIT_LOCALTIME
+/*
+** Assuming the input DateTime is UTC, move it to its localtime equivalent.
+*/
+static int toLocaltime(
+  DateTime *p,                   /* Date at which to calculate offset */
+  sqlite3_context *pCtx          /* Write error here if one occurs */
+){
+  time_t t;
+  struct tm sLocal;
+  int iYearDiff;
+
+  /* Initialize the contents of sLocal to avoid a compiler warning. */
+  memset(&sLocal, 0, sizeof(sLocal));
+
+  computeJD(p);
+  if( p->iJD<2108667600*(i64)100000 /* 1970-01-01 */
+   || p->iJD>2130141456*(i64)100000 /* 2038-01-18 */
+  ){
+    /* EVIDENCE-OF: R-55269-29598 The localtime_r() C function normally only
+    ** works for years between 1970 and 2037. For dates outside this range,
+    ** SQLite attempts to map the year into an equivalent year within this
+    ** range, do the calculation, then map the year back.
+    */
+    DateTime x = *p;
+    computeYMD_HMS(&x);
+    iYearDiff = (2000 + x.Y%4) - x.Y;
+    x.Y += iYearDiff;
+    x.validJD = 0;
+    computeJD(&x);
+    t = (time_t)(x.iJD/1000 -  21086676*(i64)10000);
+  }else{
+    iYearDiff = 0;
+    t = (time_t)(p->iJD/1000 -  21086676*(i64)10000);
+  }
+  if( osLocaltime(&t, &sLocal) ){
+    sqlite3_result_error(pCtx, "local time unavailable", -1);
+    return SQLITE_ERROR;
+  }
+  p->Y = sLocal.tm_year + 1900 - iYearDiff;
+  p->M = sLocal.tm_mon + 1;
+  p->D = sLocal.tm_mday;
+  p->h = sLocal.tm_hour;
+  p->m = sLocal.tm_min;
+  p->s = sLocal.tm_sec + (p->iJD%1000)*0.001;
+  p->validYMD = 1;
+  p->validHMS = 1;
+  p->validJD = 0;
+  p->rawS = 0;
+  p->tz = 0;
+  p->isError = 0;
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_LOCALTIME */
+
+/*
+** The following table defines various date transformations of the form
+**
+**            'NNN days'
+**
+** Where NNN is an arbitrary floating-point number and "days" can be one
+** of several units of time.
+*/
+static const struct {
+  u8 nName;           /* Length of the name */
+  char zName[7];      /* Name of the transformation */
+  float rLimit;       /* Maximum NNN value for this transform */
+  float rXform;       /* Constant used for this transform */
+} aXformType[] = {
+  /* 0 */ { 6, "second",   4.6427e+14,         1.0  },
+  /* 1 */ { 6, "minute",   7.7379e+12,        60.0  },
+  /* 2 */ { 4, "hour",     1.2897e+11,      3600.0  },
+  /* 3 */ { 3, "day",      5373485.0,      86400.0  },
+  /* 4 */ { 5, "month",    176546.0,     2592000.0  },
+  /* 5 */ { 4, "year",     14713.0,     31536000.0  },
+};
+
+/*
+** If the DateTime p is raw number, try to figure out if it is
+** a julian day number of a unix timestamp.  Set the p value
+** appropriately.
+*/
+static void autoAdjustDate(DateTime *p){
+  if( !p->rawS || p->validJD ){
+    p->rawS = 0;
+  }else if( p->s>=-21086676*(i64)10000        /* -4713-11-24 12:00:00 */
+         && p->s<=(25340230*(i64)10000)+799   /*  9999-12-31 23:59:59 */
+  ){
+    double r = p->s*1000.0 + 210866760000000.0;
+    clearYMD_HMS_TZ(p);
+    p->iJD = (sqlite3_int64)(r + 0.5);
+    p->validJD = 1;
+    p->rawS = 0;
+  }
+}
+
+/*
+** Process a modifier to a date-time stamp.  The modifiers are
+** as follows:
+**
+**     NNN days
+**     NNN hours
+**     NNN minutes
+**     NNN.NNNN seconds
+**     NNN months
+**     NNN years
+**     +/-YYYY-MM-DD HH:MM:SS.SSS
+**     ceiling
+**     floor
+**     start of month
+**     start of year
+**     start of week
+**     start of day
+**     weekday N
+**     unixepoch
+**     auto
+**     localtime
+**     utc
+**     subsec
+**     subsecond
+**
+** Return 0 on success and 1 if there is any kind of error. If the error
+** is in a system call (i.e. localtime()), then an error message is written
+** to context pCtx. If the error is an unrecognized modifier, no error is
+** written to pCtx.
+*/
+static int parseModifier(
+  sqlite3_context *pCtx,      /* Function context */
+  const char *z,              /* The text of the modifier */
+  int n,                      /* Length of zMod in bytes */
+  DateTime *p,                /* The date/time value to be modified */
+  int idx                     /* Parameter index of the modifier */
+){
+  int rc = 1;
+  double r;
+  switch(sqlite3UpperToLower[(u8)z[0]] ){
+    case 'a': {
+      /*
+      **    auto
+      **
+      ** If rawS is available, then interpret as a julian day number, or
+      ** a unix timestamp, depending on its magnitude.
+      */
+      if( sqlite3_stricmp(z, "auto")==0 ){
+        if( idx>1 ) return 1; /* IMP: R-33611-57934 */
+        autoAdjustDate(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 'c': {
+      /*
+      **    ceiling
+      **
+      ** Resolve day-of-month overflow by rolling forward into the next
+      ** month.  As this is the default action, this modifier is really
+      ** a no-op that is only included for symmetry.  See "floor".
+      */
+      if( sqlite3_stricmp(z, "ceiling")==0 ){
+        computeJD(p);
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+        p->nFloor = 0;
+      }
+      break;
+    }
+    case 'f': {
+      /*
+      **    floor
+      **
+      ** Resolve day-of-month overflow by rolling back to the end of the
+      ** previous month.
+      */
+      if( sqlite3_stricmp(z, "floor")==0 ){
+        computeJD(p);
+        p->iJD -= p->nFloor*86400000;
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 'j': {
+      /*
+      **    julianday
+      **
+      ** Always interpret the prior number as a julian-day value.  If this
+      ** is not the first modifier, or if the prior argument is not a numeric
+      ** value in the allowed range of julian day numbers understood by
+      ** SQLite (0..5373484.5) then the result will be NULL.
+      */
+      if( sqlite3_stricmp(z, "julianday")==0 ){
+        if( idx>1 ) return 1;  /* IMP: R-31176-64601 */
+        if( p->validJD && p->rawS ){
+          rc = 0;
+          p->rawS = 0;
+        }
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_LOCALTIME
+    case 'l': {
+      /*    localtime
+      **
+      ** Assuming the current time value is UTC (a.k.a. GMT), shift it to
+      ** show local time.
+      */
+      if( sqlite3_stricmp(z, "localtime")==0 && sqlite3NotPureFunc(pCtx) ){
+        rc = p->isLocal ? SQLITE_OK : toLocaltime(p, pCtx);
+        p->isUtc = 0;
+        p->isLocal = 1;
+      }
+      break;
+    }
+#endif
+    case 'u': {
+      /*
+      **    unixepoch
+      **
+      ** Treat the current value of p->s as the number of
+      ** seconds since 1970.  Convert to a real julian day number.
+      */
+      if( sqlite3_stricmp(z, "unixepoch")==0 && p->rawS ){
+        if( idx>1 ) return 1;  /* IMP: R-49255-55373 */
+        r = p->s*1000.0 + 210866760000000.0;
+        if( r>=0.0 && r<464269060800000.0 ){
+          clearYMD_HMS_TZ(p);
+          p->iJD = (sqlite3_int64)(r + 0.5);
+          p->validJD = 1;
+          p->rawS = 0;
+          rc = 0;
+        }
+      }
+#ifndef SQLITE_OMIT_LOCALTIME
+      else if( sqlite3_stricmp(z, "utc")==0 && sqlite3NotPureFunc(pCtx) ){
+        if( p->isUtc==0 ){
+          i64 iOrigJD;              /* Original localtime */
+          i64 iGuess;               /* Guess at the corresponding utc time */
+          int cnt = 0;              /* Safety to prevent infinite loop */
+          i64 iErr;                 /* Guess is off by this much */
+
+          computeJD(p);
+          iGuess = iOrigJD = p->iJD;
+          iErr = 0;
+          do{
+            DateTime new;
+            memset(&new, 0, sizeof(new));
+            iGuess -= iErr;
+            new.iJD = iGuess;
+            new.validJD = 1;
+            rc = toLocaltime(&new, pCtx);
+            if( rc ) return rc;
+            computeJD(&new);
+            iErr = new.iJD - iOrigJD;
+          }while( iErr && cnt++<3 );
+          memset(p, 0, sizeof(*p));
+          p->iJD = iGuess;
+          p->validJD = 1;
+          p->isUtc = 1;
+          p->isLocal = 0;
+        }
+        rc = SQLITE_OK;
+      }
+#endif
+      break;
+    }
+    case 'w': {
+      /*
+      **    weekday N
+      **
+      ** Move the date to the same time on the next occurrence of
+      ** weekday N where 0==Sunday, 1==Monday, and so forth.  If the
+      ** date is already on the appropriate weekday, this is a no-op.
+      */
+      if( sqlite3_strnicmp(z, "weekday ", 8)==0
+               && sqlite3AtoF(&z[8], &r, sqlite3Strlen30(&z[8]), SQLITE_UTF8)>0
+               && r>=0.0 && r<7.0 && (n=(int)r)==r ){
+        sqlite3_int64 Z;
+        computeYMD_HMS(p);
+        p->tz = 0;
+        p->validJD = 0;
+        computeJD(p);
+        Z = ((p->iJD + 129600000)/86400000) % 7;
+        if( Z>n ) Z -= 7;
+        p->iJD += (n - Z)*86400000;
+        clearYMD_HMS_TZ(p);
+        rc = 0;
+      }
+      break;
+    }
+    case 's': {
+      /*
+      **    start of TTTTT
+      **
+      ** Move the date backwards to the beginning of the current day,
+      ** or month or year.
+      **
+      **    subsecond
+      **    subsec
+      **
+      ** Show subsecond precision in the output of datetime() and
+      ** unixepoch() and strftime('%s').
+      */
+      if( sqlite3_strnicmp(z, "start of ", 9)!=0 ){
+        if( sqlite3_stricmp(z, "subsec")==0
+         || sqlite3_stricmp(z, "subsecond")==0
+        ){
+          p->useSubsec = 1;
+          rc = 0;
+        }
+        break;
+      }
+      if( !p->validJD && !p->validYMD && !p->validHMS ) break;
+      z += 9;
+      computeYMD(p);
+      p->validHMS = 1;
+      p->h = p->m = 0;
+      p->s = 0.0;
+      p->rawS = 0;
+      p->tz = 0;
+      p->validJD = 0;
+      if( sqlite3_stricmp(z,"month")==0 ){
+        p->D = 1;
+        rc = 0;
+      }else if( sqlite3_stricmp(z,"year")==0 ){
+        p->M = 1;
+        p->D = 1;
+        rc = 0;
+      }else if( sqlite3_stricmp(z,"day")==0 ){
+        rc = 0;
+      }
+      break;
+    }
+    case '+':
+    case '-':
+    case '0':
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+    case '8':
+    case '9': {
+      double rRounder;
+      int i;
+      int Y,M,D,h,m,x;
+      const char *z2 = z;
+      char z0 = z[0];
+      for(n=1; z[n]; n++){
+        if( z[n]==':' ) break;
+        if( sqlite3Isspace(z[n]) ) break;
+        if( z[n]=='-' ){
+          if( n==5 && getDigits(&z[1], "40f", &Y)==1 ) break;
+          if( n==6 && getDigits(&z[1], "50f", &Y)==1 ) break;
+        }
+      }
+      if( sqlite3AtoF(z, &r, n, SQLITE_UTF8)<=0 ){
+        assert( rc==1 );
+        break;
+      }
+      if( z[n]=='-' ){
+        /* A modifier of the form (+|-)YYYY-MM-DD adds or subtracts the
+        ** specified number of years, months, and days.  MM is limited to
+        ** the range 0-11 and DD is limited to 0-30.
+        */
+        if( z0!='+' && z0!='-' ) break;  /* Must start with +/- */
+        if( n==5 ){
+          if( getDigits(&z[1], "40f-20a-20d", &Y, &M, &D)!=3 ) break;
+        }else{
+          assert( n==6 );
+          if( getDigits(&z[1], "50f-20a-20d", &Y, &M, &D)!=3 ) break;
+          z++;
+        }
+        if( M>=12 ) break;                   /* M range 0..11 */
+        if( D>=31 ) break;                   /* D range 0..30 */
+        computeYMD_HMS(p);
+        p->validJD = 0;
+        if( z0=='-' ){
+          p->Y -= Y;
+          p->M -= M;
+          D = -D;
+        }else{
+          p->Y += Y;
+          p->M += M;
+        }
+        x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
+        p->Y += x;
+        p->M -= x*12;
+        computeFloor(p);
+        computeJD(p);
+        p->validHMS = 0;
+        p->validYMD = 0;
+        p->iJD += (i64)D*86400000;
+        if( z[11]==0 ){
+          rc = 0;
+          break;
+        }
+        if( sqlite3Isspace(z[11])
+         && getDigits(&z[12], "20c:20e", &h, &m)==2
+        ){
+          z2 = &z[12];
+          n = 2;
+        }else{
+          break;
+        }
+      }
+      if( z2[n]==':' ){
+        /* A modifier of the form (+|-)HH:MM:SS.FFF adds (or subtracts) the
+        ** specified number of hours, minutes, seconds, and fractional seconds
+        ** to the time.  The ".FFF" may be omitted.  The ":SS.FFF" may be
+        ** omitted.
+        */
+
+        DateTime tx;
+        sqlite3_int64 day;
+        if( !sqlite3Isdigit(*z2) ) z2++;
+        memset(&tx, 0, sizeof(tx));
+        if( parseHhMmSs(z2, &tx) ) break;
+        computeJD(&tx);
+        tx.iJD -= 43200000;
+        day = tx.iJD/86400000;
+        tx.iJD -= day*86400000;
+        if( z0=='-' ) tx.iJD = -tx.iJD;
+        computeJD(p);
+        clearYMD_HMS_TZ(p);
+        p->iJD += tx.iJD;
+        rc = 0;
+        break;
+      }
+
+      /* If control reaches this point, it means the transformation is
+      ** one of the forms like "+NNN days".  */
+      z += n;
+      while( sqlite3Isspace(*z) ) z++;
+      n = sqlite3Strlen30(z);
+      if( n<3 || n>10 ) break;
+      if( sqlite3UpperToLower[(u8)z[n-1]]=='s' ) n--;
+      computeJD(p);
+      assert( rc==1 );
+      rRounder = r<0 ? -0.5 : +0.5;
+      p->nFloor = 0;
+      for(i=0; i<ArraySize(aXformType); i++){
+        if( aXformType[i].nName==n
+         && sqlite3_strnicmp(aXformType[i].zName, z, n)==0
+         && r>-aXformType[i].rLimit && r<aXformType[i].rLimit
+        ){
+          switch( i ){
+            case 4: { /* Special processing to add months */
+              assert( strcmp(aXformType[4].zName,"month")==0 );
+              computeYMD_HMS(p);
+              p->M += (int)r;
+              x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
+              p->Y += x;
+              p->M -= x*12;
+              computeFloor(p);
+              p->validJD = 0;
+              r -= (int)r;
+              break;
+            }
+            case 5: { /* Special processing to add years */
+              int y = (int)r;
+              assert( strcmp(aXformType[5].zName,"year")==0 );
+              computeYMD_HMS(p);
+              assert( p->M>=0 && p->M<=12 );
+              p->Y += y;
+              computeFloor(p);
+              p->validJD = 0;
+              r -= (int)r;
+              break;
+            }
+          }
+          computeJD(p);
+          p->iJD += (sqlite3_int64)(r*1000.0*aXformType[i].rXform + rRounder);
+          rc = 0;
+          break;
+        }
+      }
+      clearYMD_HMS_TZ(p);
+      break;
+    }
+    default: {
+      break;
+    }
+  }
+  return rc;
+}
+
+/*
+** Process time function arguments.  argv[0] is a date-time stamp.
+** argv[1] and following are modifiers.  Parse them all and write
+** the resulting time into the DateTime structure p.  Return 0
+** on success and 1 if there are any errors.
+**
+** If there are zero parameters (if even argv[0] is undefined)
+** then assume a default value of "now" for argv[0].
+*/
+static int isDate(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv,
+  DateTime *p
+){
+  int i, n;
+  const unsigned char *z;
+  int eType;
+  memset(p, 0, sizeof(*p));
+  if( argc==0 ){
+    if( !sqlite3NotPureFunc(context) ) return 1;
+    return setDateTimeToCurrent(context, p);
+  }
+  if( (eType = sqlite3_value_type(argv[0]))==SQLITE_FLOAT
+                   || eType==SQLITE_INTEGER ){
+    setRawDateNumber(p, sqlite3_value_double(argv[0]));
+  }else{
+    z = sqlite3_value_text(argv[0]);
+    if( !z || parseDateOrTime(context, (char*)z, p) ){
+      return 1;
+    }
+  }
+  for(i=1; i<argc; i++){
+    z = sqlite3_value_text(argv[i]);
+    n = sqlite3_value_bytes(argv[i]);
+    if( z==0 || parseModifier(context, (char*)z, n, p, i) ) return 1;
+  }
+  computeJD(p);
+  if( p->isError || !validJulianDay(p->iJD) ) return 1;
+  if( argc==1 && p->validYMD && p->D>28 ){
+    /* Make sure a YYYY-MM-DD is normalized.
+    ** Example: 2023-02-31 -> 2023-03-03 */
+    assert( p->validJD );
+    p->validYMD = 0;
+  }
+  return 0;
+}
+
+
+/*
+** The following routines implement the various date and time functions
+** of SQLite.
+*/
+
+/*
+**    julianday( TIMESTRING, MOD, MOD, ...)
+**
+** Return the julian day number of the date specified in the arguments
+*/
+static void juliandayFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    computeJD(&x);
+    sqlite3_result_double(context, x.iJD/86400000.0);
+  }
+}
+
+/*
+**    unixepoch( TIMESTRING, MOD, MOD, ...)
+**
+** Return the number of seconds (including fractional seconds) since
+** the unix epoch of 1970-01-01 00:00:00 GMT.
+*/
+static void unixepochFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    computeJD(&x);
+    if( x.useSubsec ){
+      sqlite3_result_double(context, (x.iJD - 21086676*(i64)10000000)/1000.0);
+    }else{
+      sqlite3_result_int64(context, x.iJD/1000 - 21086676*(i64)10000);
+    }
+  }
+}
+
+/*
+**    datetime( TIMESTRING, MOD, MOD, ...)
+**
+** Return YYYY-MM-DD HH:MM:SS
+*/
+static void datetimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    int Y, s, n;
+    char zBuf[32];
+    computeYMD_HMS(&x);
+    Y = x.Y;
+    if( Y<0 ) Y = -Y;
+    zBuf[1] = '0' + (Y/1000)%10;
+    zBuf[2] = '0' + (Y/100)%10;
+    zBuf[3] = '0' + (Y/10)%10;
+    zBuf[4] = '0' + (Y)%10;
+    zBuf[5] = '-';
+    zBuf[6] = '0' + (x.M/10)%10;
+    zBuf[7] = '0' + (x.M)%10;
+    zBuf[8] = '-';
+    zBuf[9] = '0' + (x.D/10)%10;
+    zBuf[10] = '0' + (x.D)%10;
+    zBuf[11] = ' ';
+    zBuf[12] = '0' + (x.h/10)%10;
+    zBuf[13] = '0' + (x.h)%10;
+    zBuf[14] = ':';
+    zBuf[15] = '0' + (x.m/10)%10;
+    zBuf[16] = '0' + (x.m)%10;
+    zBuf[17] = ':';
+    if( x.useSubsec ){
+      s = (int)(1000.0*x.s + 0.5);
+      zBuf[18] = '0' + (s/10000)%10;
+      zBuf[19] = '0' + (s/1000)%10;
+      zBuf[20] = '.';
+      zBuf[21] = '0' + (s/100)%10;
+      zBuf[22] = '0' + (s/10)%10;
+      zBuf[23] = '0' + (s)%10;
+      zBuf[24] = 0;
+      n = 24;
+    }else{
+      s = (int)x.s;
+      zBuf[18] = '0' + (s/10)%10;
+      zBuf[19] = '0' + (s)%10;
+      zBuf[20] = 0;
+      n = 20;
+    }
+    if( x.Y<0 ){
+      zBuf[0] = '-';
+      sqlite3_result_text(context, zBuf, n, SQLITE_TRANSIENT);
+    }else{
+      sqlite3_result_text(context, &zBuf[1], n-1, SQLITE_TRANSIENT);
+    }
+  }
+}
+
+/*
+**    time( TIMESTRING, MOD, MOD, ...)
+**
+** Return HH:MM:SS
+*/
+static void timeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    int s, n;
+    char zBuf[16];
+    computeHMS(&x);
+    zBuf[0] = '0' + (x.h/10)%10;
+    zBuf[1] = '0' + (x.h)%10;
+    zBuf[2] = ':';
+    zBuf[3] = '0' + (x.m/10)%10;
+    zBuf[4] = '0' + (x.m)%10;
+    zBuf[5] = ':';
+    if( x.useSubsec ){
+      s = (int)(1000.0*x.s + 0.5);
+      zBuf[6] = '0' + (s/10000)%10;
+      zBuf[7] = '0' + (s/1000)%10;
+      zBuf[8] = '.';
+      zBuf[9] = '0' + (s/100)%10;
+      zBuf[10] = '0' + (s/10)%10;
+      zBuf[11] = '0' + (s)%10;
+      zBuf[12] = 0;
+      n = 12;
+    }else{
+      s = (int)x.s;
+      zBuf[6] = '0' + (s/10)%10;
+      zBuf[7] = '0' + (s)%10;
+      zBuf[8] = 0;
+      n = 8;
+    }
+    sqlite3_result_text(context, zBuf, n, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+**    date( TIMESTRING, MOD, MOD, ...)
+**
+** Return YYYY-MM-DD
+*/
+static void dateFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    int Y;
+    char zBuf[16];
+    computeYMD(&x);
+    Y = x.Y;
+    if( Y<0 ) Y = -Y;
+    zBuf[1] = '0' + (Y/1000)%10;
+    zBuf[2] = '0' + (Y/100)%10;
+    zBuf[3] = '0' + (Y/10)%10;
+    zBuf[4] = '0' + (Y)%10;
+    zBuf[5] = '-';
+    zBuf[6] = '0' + (x.M/10)%10;
+    zBuf[7] = '0' + (x.M)%10;
+    zBuf[8] = '-';
+    zBuf[9] = '0' + (x.D/10)%10;
+    zBuf[10] = '0' + (x.D)%10;
+    zBuf[11] = 0;
+    if( x.Y<0 ){
+      zBuf[0] = '-';
+      sqlite3_result_text(context, zBuf, 11, SQLITE_TRANSIENT);
+    }else{
+      sqlite3_result_text(context, &zBuf[1], 10, SQLITE_TRANSIENT);
+    }
+  }
+}
+
+/*
+** Compute the number of days after the most recent January 1.
+**
+** In other words, compute the zero-based day number for the
+** current year:
+**
+**   Jan01 = 0,  Jan02 = 1, ..., Jan31 = 30, Feb01 = 31, ...
+**   Dec31 = 364 or 365.
+*/
+static int daysAfterJan01(DateTime *pDate){
+  DateTime jan01 = *pDate;
+  assert( jan01.validYMD );
+  assert( jan01.validHMS );
+  assert( pDate->validJD );
+  jan01.validJD = 0;
+  jan01.M = 1;
+  jan01.D = 1;
+  computeJD(&jan01);
+  return (int)((pDate->iJD-jan01.iJD+43200000)/86400000);
+}
+
+/*
+** Return the number of days after the most recent Monday.
+**
+** In other words, return the day of the week according
+** to this code:
+**
+**   0=Monday, 1=Tuesday, 2=Wednesday, ..., 6=Sunday.
+*/
+static int daysAfterMonday(DateTime *pDate){
+  assert( pDate->validJD );
+  return (int)((pDate->iJD+43200000)/86400000) % 7;
+}
+
+/*
+** Return the number of days after the most recent Sunday.
+**
+** In other words, return the day of the week according
+** to this code:
+**
+**   0=Sunday, 1=Monday, 2=Tues, ..., 6=Saturday
+*/
+static int daysAfterSunday(DateTime *pDate){
+  assert( pDate->validJD );
+  return (int)((pDate->iJD+129600000)/86400000) % 7;
+}
+
+/*
+**    strftime( FORMAT, TIMESTRING, MOD, MOD, ...)
+**
+** Return a string described by FORMAT.  Conversions as follows:
+**
+**   %d  day of month  01-31
+**   %e  day of month  1-31
+**   %f  ** fractional seconds  SS.SSS
+**   %F  ISO date.  YYYY-MM-DD
+**   %G  ISO year corresponding to %V 0000-9999.
+**   %g  2-digit ISO year corresponding to %V 00-99
+**   %H  hour 00-24
+**   %k  hour  0-24  (leading zero converted to space)
+**   %I  hour 01-12
+**   %j  day of year 001-366
+**   %J  ** julian day number
+**   %l  hour  1-12  (leading zero converted to space)
+**   %m  month 01-12
+**   %M  minute 00-59
+**   %p  "am" or "pm"
+**   %P  "AM" or "PM"
+**   %R  time as HH:MM
+**   %s  seconds since 1970-01-01
+**   %S  seconds 00-59
+**   %T  time as HH:MM:SS
+**   %u  day of week 1-7  Monday==1, Sunday==7
+**   %w  day of week 0-6  Sunday==0, Monday==1
+**   %U  week of year 00-53  (First Sunday is start of week 01)
+**   %V  week of year 01-53  (First week containing Thursday is week 01)
+**   %W  week of year 00-53  (First Monday is start of week 01)
+**   %Y  year 0000-9999
+**   %%  %
+*/
+static void strftimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  size_t i,j;
+  sqlite3 *db;
+  const char *zFmt;
+  sqlite3_str sRes;
+
+
+  if( argc==0 ) return;
+  zFmt = (const char*)sqlite3_value_text(argv[0]);
+  if( zFmt==0 || isDate(context, argc-1, argv+1, &x) ) return;
+  db = sqlite3_context_db_handle(context);
+  sqlite3StrAccumInit(&sRes, 0, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
+
+  computeJD(&x);
+  computeYMD_HMS(&x);
+  for(i=j=0; zFmt[i]; i++){
+    char cf;
+    if( zFmt[i]!='%' ) continue;
+    if( j<i ) sqlite3_str_append(&sRes, zFmt+j, (int)(i-j));
+    i++;
+    j = i + 1;
+    cf = zFmt[i];
+    switch( cf ){
+      case 'd':  /* Fall thru */
+      case 'e': {
+        sqlite3_str_appendf(&sRes, cf=='d' ? "%02d" : "%2d", x.D);
+        break;
+      }
+      case 'f': {  /* Fractional seconds.  (Non-standard) */
+        double s = x.s;
+        if( NEVER(s>59.999) ) s = 59.999;
+        sqlite3_str_appendf(&sRes, "%06.3f", s);
+        break;
+      }
+      case 'F': {
+        sqlite3_str_appendf(&sRes, "%04d-%02d-%02d", x.Y, x.M, x.D);
+        break;
+      }
+      case 'G': /* Fall thru */
+      case 'g': {
+        DateTime y = x;
+        assert( y.validJD );
+        /* Move y so that it is the Thursday in the same week as x */
+        y.iJD += (3 - daysAfterMonday(&x))*86400000;
+        y.validYMD = 0;
+        computeYMD(&y);
+        if( cf=='g' ){
+          sqlite3_str_appendf(&sRes, "%02d", y.Y%100);
+        }else{
+          sqlite3_str_appendf(&sRes, "%04d", y.Y);
+        }
+        break;
+      }
+      case 'H':
+      case 'k': {
+        sqlite3_str_appendf(&sRes, cf=='H' ? "%02d" : "%2d", x.h);
+        break;
+      }
+      case 'I': /* Fall thru */
+      case 'l': {
+        int h = x.h;
+        if( h>12 ) h -= 12;
+        if( h==0 ) h = 12;
+        sqlite3_str_appendf(&sRes, cf=='I' ? "%02d" : "%2d", h);
+        break;
+      }
+      case 'j': {  /* Day of year.  Jan01==1, Jan02==2, and so forth */
+        sqlite3_str_appendf(&sRes,"%03d",daysAfterJan01(&x)+1);
+        break;
+      }
+      case 'J': {  /* Julian day number.  (Non-standard) */
+        sqlite3_str_appendf(&sRes,"%.16g",x.iJD/86400000.0);
+        break;
+      }
+      case 'm': {
+        sqlite3_str_appendf(&sRes,"%02d",x.M);
+        break;
+      }
+      case 'M': {
+        sqlite3_str_appendf(&sRes,"%02d",x.m);
+        break;
+      }
+      case 'p': /* Fall thru */
+      case 'P': {
+        if( x.h>=12 ){
+          sqlite3_str_append(&sRes, cf=='p' ? "PM" : "pm", 2);
+        }else{
+          sqlite3_str_append(&sRes, cf=='p' ? "AM" : "am", 2);
+        }
+        break;
+      }
+      case 'R': {
+        sqlite3_str_appendf(&sRes, "%02d:%02d", x.h, x.m);
+        break;
+      }
+      case 's': {
+        if( x.useSubsec ){
+          sqlite3_str_appendf(&sRes,"%.3f",
+                (x.iJD - 21086676*(i64)10000000)/1000.0);
+        }else{
+          i64 iS = (i64)(x.iJD/1000 - 21086676*(i64)10000);
+          sqlite3_str_appendf(&sRes,"%lld",iS);
+        }
+        break;
+      }
+      case 'S': {
+        sqlite3_str_appendf(&sRes,"%02d",(int)x.s);
+        break;
+      }
+      case 'T': {
+        sqlite3_str_appendf(&sRes,"%02d:%02d:%02d", x.h, x.m, (int)x.s);
+        break;
+      }
+      case 'u':    /* Day of week.  1 to 7.  Monday==1, Sunday==7 */
+      case 'w': {  /* Day of week.  0 to 6.  Sunday==0, Monday==1 */
+        char c = (char)daysAfterSunday(&x) + '0';
+        if( c=='0' && cf=='u' ) c = '7';
+        sqlite3_str_appendchar(&sRes, 1, c);
+        break;
+      }
+      case 'U': {  /* Week num. 00-53. First Sun of the year is week 01 */
+        sqlite3_str_appendf(&sRes,"%02d",
+              (daysAfterJan01(&x)-daysAfterSunday(&x)+7)/7);
+        break;
+      }
+      case 'V': {  /* Week num. 01-53. First week with a Thur is week 01 */
+        DateTime y = x;
+        /* Adjust y so that is the Thursday in the same week as x */
+        assert( y.validJD );
+        y.iJD += (3 - daysAfterMonday(&x))*86400000;
+        y.validYMD = 0;
+        computeYMD(&y);
+        sqlite3_str_appendf(&sRes,"%02d", daysAfterJan01(&y)/7+1);
+        break;
+      }
+      case 'W': {  /* Week num. 00-53. First Mon of the year is week 01 */
+        sqlite3_str_appendf(&sRes,"%02d",
+           (daysAfterJan01(&x)-daysAfterMonday(&x)+7)/7);
+        break;
+      }
+      case 'Y': {
+        sqlite3_str_appendf(&sRes,"%04d",x.Y);
+        break;
+      }
+      case '%': {
+        sqlite3_str_appendchar(&sRes, 1, '%');
+        break;
+      }
+      default: {
+        sqlite3_str_reset(&sRes);
+        return;
+      }
+    }
+  }
+  if( j<i ) sqlite3_str_append(&sRes, zFmt+j, (int)(i-j));
+  sqlite3ResultStrAccum(context, &sRes);
+}
+
+/*
+** current_time()
+**
+** This function returns the same value as time('now').
+*/
+static void ctimeFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  timeFunc(context, 0, 0);
+}
+
+/*
+** current_date()
+**
+** This function returns the same value as date('now').
+*/
+static void cdateFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  dateFunc(context, 0, 0);
+}
+
+/*
+** timediff(DATE1, DATE2)
+**
+** Return the amount of time that must be added to DATE2 in order to
+** convert it into DATE2.  The time difference format is:
+**
+**     +YYYY-MM-DD HH:MM:SS.SSS
+**
+** The initial "+" becomes "-" if DATE1 occurs before DATE2.  For
+** date/time values A and B, the following invariant should hold:
+**
+**     datetime(A) == (datetime(B, timediff(A,B))
+**
+** Both DATE arguments must be either a julian day number, or an
+** ISO-8601 string.  The unix timestamps are not supported by this
+** routine.
+*/
+static void timediffFunc(
+  sqlite3_context *context,
+  int NotUsed1,
+  sqlite3_value **argv
+){
+  char sign;
+  int Y, M;
+  DateTime d1, d2;
+  sqlite3_str sRes;
+  UNUSED_PARAMETER(NotUsed1);
+  if( isDate(context, 1, &argv[0], &d1) ) return;
+  if( isDate(context, 1, &argv[1], &d2) ) return;
+  computeYMD_HMS(&d1);
+  computeYMD_HMS(&d2);
+  if( d1.iJD>=d2.iJD ){
+    sign = '+';
+    Y = d1.Y - d2.Y;
+    if( Y ){
+      d2.Y = d1.Y;
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    M = d1.M - d2.M;
+    if( M<0 ){
+      Y--;
+      M += 12;
+    }
+    if( M!=0 ){
+      d2.M = d1.M;
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    while( d1.iJD<d2.iJD ){
+      M--;
+      if( M<0 ){
+        M = 11;
+        Y--;
+      }
+      d2.M--;
+      if( d2.M<1 ){
+        d2.M = 12;
+        d2.Y--;
+      }
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    d1.iJD -= d2.iJD;
+    d1.iJD += (u64)1486995408 * (u64)100000;
+  }else /* d1<d2 */{
+    sign = '-';
+    Y = d2.Y - d1.Y;
+    if( Y ){
+      d2.Y = d1.Y;
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    M = d2.M - d1.M;
+    if( M<0 ){
+      Y--;
+      M += 12;
+    }
+    if( M!=0 ){
+      d2.M = d1.M;
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    while( d1.iJD>d2.iJD ){
+      M--;
+      if( M<0 ){
+        M = 11;
+        Y--;
+      }
+      d2.M++;
+      if( d2.M>12 ){
+        d2.M = 1;
+        d2.Y++;
+      }
+      d2.validJD = 0;
+      computeJD(&d2);
+    }
+    d1.iJD = d2.iJD - d1.iJD;
+    d1.iJD += (u64)1486995408 * (u64)100000;
+  }
+  clearYMD_HMS_TZ(&d1);
+  computeYMD_HMS(&d1);
+  sqlite3StrAccumInit(&sRes, 0, 0, 0, 100);
+  sqlite3_str_appendf(&sRes, "%c%04d-%02d-%02d %02d:%02d:%06.3f",
+       sign, Y, M, d1.D-1, d1.h, d1.m, d1.s);
+  sqlite3ResultStrAccum(context, &sRes);
+}
+
+
+/*
+** current_timestamp()
+**
+** This function returns the same value as datetime('now').
+*/
+static void ctimestampFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  datetimeFunc(context, 0, 0);
+}
+#endif /* !defined(SQLITE_OMIT_DATETIME_FUNCS) */
+
+#ifdef SQLITE_OMIT_DATETIME_FUNCS
+/*
+** If the library is compiled to omit the full-scale date and time
+** handling (to get a smaller binary), the following minimal version
+** of the functions current_time(), current_date() and current_timestamp()
+** are included instead. This is to support column declarations that
+** include "DEFAULT CURRENT_TIME" etc.
+**
+** This function uses the C-library functions time(), gmtime()
+** and strftime(). The format string to pass to strftime() is supplied
+** as the user-data for the function.
+*/
+static void currentTimeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  time_t t;
+  char *zFormat = (char *)sqlite3_user_data(context);
+  sqlite3_int64 iT;
+  struct tm *pTm;
+  struct tm sNow;
+  char zBuf[20];
+
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+
+  iT = sqlite3StmtCurrentTime(context);
+  if( iT<=0 ) return;
+  t = iT/1000 - 10000*(sqlite3_int64)21086676;
+#if HAVE_GMTIME_R
+  pTm = gmtime_r(&t, &sNow);
+#else
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN));
+  pTm = gmtime(&t);
+  if( pTm ) memcpy(&sNow, pTm, sizeof(sNow));
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN));
+#endif
+  if( pTm ){
+    strftime(zBuf, 20, zFormat, &sNow);
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+  }
+}
+#endif
+
+#if !defined(SQLITE_OMIT_DATETIME_FUNCS) && defined(SQLITE_DEBUG)
+/*
+**   datedebug(...)
+**
+** This routine returns JSON that describes the internal DateTime object.
+** Used for debugging and testing only.  Subject to change.
+*/
+static void datedebugFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  DateTime x;
+  if( isDate(context, argc, argv, &x)==0 ){
+    char *zJson;
+    zJson = sqlite3_mprintf(
+      "{iJD:%lld,Y:%d,M:%d,D:%d,h:%d,m:%d,tz:%d,"
+      "s:%.3f,validJD:%d,validYMS:%d,validHMS:%d,"
+      "nFloor:%d,rawS:%d,isError:%d,useSubsec:%d,"
+      "isUtc:%d,isLocal:%d}",
+      x.iJD, x.Y, x.M, x.D, x.h, x.m, x.tz,
+      x.s, x.validJD, x.validYMD, x.validHMS,
+      x.nFloor, x.rawS, x.isError, x.useSubsec,
+      x.isUtc, x.isLocal);
+    sqlite3_result_text(context, zJson, -1, sqlite3_free);
+  }
+}
+#endif /* !SQLITE_OMIT_DATETIME_FUNCS && SQLITE_DEBUG */
+
+
+/*
+** This function registered all of the above C functions as SQL
+** functions.  This should be the only routine in this file with
+** external linkage.
+*/
+SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void){
+  static FuncDef aDateTimeFuncs[] = {
+#ifndef SQLITE_OMIT_DATETIME_FUNCS
+    PURE_DATE(julianday,        -1, 0, 0, juliandayFunc ),
+    PURE_DATE(unixepoch,        -1, 0, 0, unixepochFunc ),
+    PURE_DATE(date,             -1, 0, 0, dateFunc      ),
+    PURE_DATE(time,             -1, 0, 0, timeFunc      ),
+    PURE_DATE(datetime,         -1, 0, 0, datetimeFunc  ),
+    PURE_DATE(strftime,         -1, 0, 0, strftimeFunc  ),
+    PURE_DATE(timediff,          2, 0, 0, timediffFunc  ),
+#ifdef SQLITE_DEBUG
+    PURE_DATE(datedebug,        -1, 0, 0, datedebugFunc ),
+#endif
+    DFUNCTION(current_time,      0, 0, 0, ctimeFunc     ),
+    DFUNCTION(current_timestamp, 0, 0, 0, ctimestampFunc),
+    DFUNCTION(current_date,      0, 0, 0, cdateFunc     ),
+#else
+    STR_FUNCTION(current_time,      0, "%H:%M:%S",          0, currentTimeFunc),
+    STR_FUNCTION(current_date,      0, "%Y-%m-%d",          0, currentTimeFunc),
+    STR_FUNCTION(current_timestamp, 0, "%Y-%m-%d %H:%M:%S", 0, currentTimeFunc),
+#endif
+  };
+  sqlite3InsertBuiltinFuncs(aDateTimeFuncs, ArraySize(aDateTimeFuncs));
+}
+
+/************** End of date.c ************************************************/
+/************** Begin file os.c **********************************************/
+/*
+** 2005 November 29
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains OS interface code that is common to all
+** architectures.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** If we compile with the SQLITE_TEST macro set, then the following block
+** of code will give us the ability to simulate a disk I/O error.  This
+** is used for testing the I/O recovery logic.
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API int sqlite3_io_error_hit = 0;            /* Total number of I/O Errors */
+SQLITE_API int sqlite3_io_error_hardhit = 0;        /* Number of non-benign errors */
+SQLITE_API int sqlite3_io_error_pending = 0;        /* Count down to first I/O error */
+SQLITE_API int sqlite3_io_error_persist = 0;        /* True if I/O errors persist */
+SQLITE_API int sqlite3_io_error_benign = 0;         /* True if errors are benign */
+SQLITE_API int sqlite3_diskfull_pending = 0;
+SQLITE_API int sqlite3_diskfull = 0;
+#endif /* defined(SQLITE_TEST) */
+
+/*
+** When testing, also keep a count of the number of open files.
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API int sqlite3_open_file_count = 0;
+#endif /* defined(SQLITE_TEST) */
+
+/*
+** The default SQLite sqlite3_vfs implementations do not allocate
+** memory (actually, os_unix.c allocates a small amount of memory
+** from within OsOpen()), but some third-party implementations may.
+** So we test the effects of a malloc() failing and the sqlite3OsXXX()
+** function returning SQLITE_IOERR_NOMEM using the DO_OS_MALLOC_TEST macro.
+**
+** The following functions are instrumented for malloc() failure
+** testing:
+**
+**     sqlite3OsRead()
+**     sqlite3OsWrite()
+**     sqlite3OsSync()
+**     sqlite3OsFileSize()
+**     sqlite3OsLock()
+**     sqlite3OsCheckReservedLock()
+**     sqlite3OsFileControl()
+**     sqlite3OsShmMap()
+**     sqlite3OsOpen()
+**     sqlite3OsDelete()
+**     sqlite3OsAccess()
+**     sqlite3OsFullPathname()
+**
+*/
+#if defined(SQLITE_TEST)
+SQLITE_API int sqlite3_memdebug_vfs_oom_test = 1;
+  #define DO_OS_MALLOC_TEST(x)                                       \
+  if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3JournalIsInMemory(x))) { \
+    void *pTstAlloc = sqlite3Malloc(10);                             \
+    if (!pTstAlloc) return SQLITE_IOERR_NOMEM_BKPT;                  \
+    sqlite3_free(pTstAlloc);                                         \
+  }
+#else
+  #define DO_OS_MALLOC_TEST(x)
+#endif
+
+/*
+** The following routines are convenience wrappers around methods
+** of the sqlite3_file object.  This is mostly just syntactic sugar. All
+** of this would be completely automatic if SQLite were coded using
+** C++ instead of plain old C.
+*/
+SQLITE_PRIVATE void sqlite3OsClose(sqlite3_file *pId){
+  if( pId->pMethods ){
+    pId->pMethods->xClose(pId);
+    pId->pMethods = 0;
+  }
+}
+SQLITE_PRIVATE int sqlite3OsRead(sqlite3_file *id, void *pBuf, int amt, i64 offset){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xRead(id, pBuf, amt, offset);
+}
+SQLITE_PRIVATE int sqlite3OsWrite(sqlite3_file *id, const void *pBuf, int amt, i64 offset){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xWrite(id, pBuf, amt, offset);
+}
+SQLITE_PRIVATE int sqlite3OsTruncate(sqlite3_file *id, i64 size){
+  return id->pMethods->xTruncate(id, size);
+}
+SQLITE_PRIVATE int sqlite3OsSync(sqlite3_file *id, int flags){
+  DO_OS_MALLOC_TEST(id);
+  return flags ? id->pMethods->xSync(id, flags) : SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3OsFileSize(sqlite3_file *id, i64 *pSize){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xFileSize(id, pSize);
+}
+SQLITE_PRIVATE int sqlite3OsLock(sqlite3_file *id, int lockType){
+  DO_OS_MALLOC_TEST(id);
+  assert( lockType>=SQLITE_LOCK_SHARED && lockType<=SQLITE_LOCK_EXCLUSIVE );
+  return id->pMethods->xLock(id, lockType);
+}
+SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file *id, int lockType){
+  assert( lockType==SQLITE_LOCK_NONE || lockType==SQLITE_LOCK_SHARED );
+  return id->pMethods->xUnlock(id, lockType);
+}
+SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xCheckReservedLock(id, pResOut);
+}
+
+/*
+** Use sqlite3OsFileControl() when we are doing something that might fail
+** and we need to know about the failures.  Use sqlite3OsFileControlHint()
+** when simply tossing information over the wall to the VFS and we do not
+** really care if the VFS receives and understands the information since it
+** is only a hint and can be safely ignored.  The sqlite3OsFileControlHint()
+** routine has no return value since the return value would be meaningless.
+*/
+SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){
+  if( id->pMethods==0 ) return SQLITE_NOTFOUND;
+#ifdef SQLITE_TEST
+  if( op!=SQLITE_FCNTL_COMMIT_PHASETWO
+   && op!=SQLITE_FCNTL_LOCK_TIMEOUT
+   && op!=SQLITE_FCNTL_CKPT_DONE
+   && op!=SQLITE_FCNTL_CKPT_START
+  ){
+    /* Faults are not injected into COMMIT_PHASETWO because, assuming SQLite
+    ** is using a regular VFS, it is called after the corresponding
+    ** transaction has been committed. Injecting a fault at this point
+    ** confuses the test scripts - the COMMIT command returns SQLITE_NOMEM
+    ** but the transaction is committed anyway.
+    **
+    ** The core must call OsFileControl() though, not OsFileControlHint(),
+    ** as if a custom VFS (e.g. zipvfs) returns an error here, it probably
+    ** means the commit really has failed and an error should be returned
+    ** to the user.
+    **
+    ** The CKPT_DONE and CKPT_START file-controls are write-only signals
+    ** to the cksumvfs.  Their return code is meaningless and is ignored
+    ** by the SQLite core, so there is no point in simulating OOMs for them.
+    */
+    DO_OS_MALLOC_TEST(id);
+  }
+#endif
+  return id->pMethods->xFileControl(id, op, pArg);
+}
+SQLITE_PRIVATE void sqlite3OsFileControlHint(sqlite3_file *id, int op, void *pArg){
+  if( id->pMethods ) (void)id->pMethods->xFileControl(id, op, pArg);
+}
+
+SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id){
+  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
+  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
+}
+SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
+  if( NEVER(id->pMethods==0) ) return 0;
+  return id->pMethods->xDeviceCharacteristics(id);
+}
+#ifndef SQLITE_OMIT_WAL
+SQLITE_PRIVATE int sqlite3OsShmLock(sqlite3_file *id, int offset, int n, int flags){
+  return id->pMethods->xShmLock(id, offset, n, flags);
+}
+SQLITE_PRIVATE void sqlite3OsShmBarrier(sqlite3_file *id){
+  id->pMethods->xShmBarrier(id);
+}
+SQLITE_PRIVATE int sqlite3OsShmUnmap(sqlite3_file *id, int deleteFlag){
+  return id->pMethods->xShmUnmap(id, deleteFlag);
+}
+SQLITE_PRIVATE int sqlite3OsShmMap(
+  sqlite3_file *id,               /* Database file handle */
+  int iPage,
+  int pgsz,
+  int bExtend,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Pointer to mapping */
+){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp);
+}
+#endif /* SQLITE_OMIT_WAL */
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/* The real implementation of xFetch and xUnfetch */
+SQLITE_PRIVATE int sqlite3OsFetch(sqlite3_file *id, i64 iOff, int iAmt, void **pp){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xFetch(id, iOff, iAmt, pp);
+}
+SQLITE_PRIVATE int sqlite3OsUnfetch(sqlite3_file *id, i64 iOff, void *p){
+  return id->pMethods->xUnfetch(id, iOff, p);
+}
+#else
+/* No-op stubs to use when memory-mapped I/O is disabled */
+SQLITE_PRIVATE int sqlite3OsFetch(sqlite3_file *id, i64 iOff, int iAmt, void **pp){
+  *pp = 0;
+  return SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3OsUnfetch(sqlite3_file *id, i64 iOff, void *p){
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** The next group of routines are convenience wrappers around the
+** VFS methods.
+*/
+SQLITE_PRIVATE int sqlite3OsOpen(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  sqlite3_file *pFile,
+  int flags,
+  int *pFlagsOut
+){
+  int rc;
+  DO_OS_MALLOC_TEST(0);
+  /* 0x87f7f is a mask of SQLITE_OPEN_ flags that are valid to be passed
+  ** down into the VFS layer.  Some SQLITE_OPEN_ flags (for example,
+  ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
+  ** reaching the VFS. */
+  assert( zPath || (flags & SQLITE_OPEN_EXCLUSIVE) );
+  rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x1087f7f, pFlagsOut);
+  assert( rc==SQLITE_OK || pFile->pMethods==0 );
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  DO_OS_MALLOC_TEST(0);
+  assert( dirSync==0 || dirSync==1 );
+  return pVfs->xDelete!=0 ? pVfs->xDelete(pVfs, zPath, dirSync) : SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3OsAccess(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int flags,
+  int *pResOut
+){
+  DO_OS_MALLOC_TEST(0);
+  return pVfs->xAccess(pVfs, zPath, flags, pResOut);
+}
+SQLITE_PRIVATE int sqlite3OsFullPathname(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int nPathOut,
+  char *zPathOut
+){
+  DO_OS_MALLOC_TEST(0);
+  zPathOut[0] = 0;
+  return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
+}
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  assert( zPath!=0 );
+  assert( strlen(zPath)<=SQLITE_MAX_PATHLEN );  /* tag-20210611-1 */
+  return pVfs->xDlOpen(pVfs, zPath);
+}
+SQLITE_PRIVATE void sqlite3OsDlError(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  pVfs->xDlError(pVfs, nByte, zBufOut);
+}
+SQLITE_PRIVATE void (*sqlite3OsDlSym(sqlite3_vfs *pVfs, void *pHdle, const char *zSym))(void){
+  return pVfs->xDlSym(pVfs, pHdle, zSym);
+}
+SQLITE_PRIVATE void sqlite3OsDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  pVfs->xDlClose(pVfs, pHandle);
+}
+#endif /* SQLITE_OMIT_LOAD_EXTENSION */
+SQLITE_PRIVATE int sqlite3OsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  if( sqlite3Config.iPrngSeed ){
+    memset(zBufOut, 0, nByte);
+    if( ALWAYS(nByte>(signed)sizeof(unsigned)) ) nByte = sizeof(unsigned int);
+    memcpy(zBufOut, &sqlite3Config.iPrngSeed, nByte);
+    return SQLITE_OK;
+  }else{
+    return pVfs->xRandomness(pVfs, nByte, zBufOut);
+  }
+
+}
+SQLITE_PRIVATE int sqlite3OsSleep(sqlite3_vfs *pVfs, int nMicro){
+  return pVfs->xSleep(pVfs, nMicro);
+}
+SQLITE_PRIVATE int sqlite3OsGetLastError(sqlite3_vfs *pVfs){
+  return pVfs->xGetLastError ? pVfs->xGetLastError(pVfs, 0, 0) : 0;
+}
+SQLITE_PRIVATE int sqlite3OsCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
+  int rc;
+  /* IMPLEMENTATION-OF: R-49045-42493 SQLite will use the xCurrentTimeInt64()
+  ** method to get the current date and time if that method is available
+  ** (if iVersion is 2 or greater and the function pointer is not NULL) and
+  ** will fall back to xCurrentTime() if xCurrentTimeInt64() is
+  ** unavailable.
+  */
+  if( pVfs->iVersion>=2 && pVfs->xCurrentTimeInt64 ){
+    rc = pVfs->xCurrentTimeInt64(pVfs, pTimeOut);
+  }else{
+    double r;
+    rc = pVfs->xCurrentTime(pVfs, &r);
+    *pTimeOut = (sqlite3_int64)(r*86400000.0);
+  }
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3OsOpenMalloc(
+  sqlite3_vfs *pVfs,
+  const char *zFile,
+  sqlite3_file **ppFile,
+  int flags,
+  int *pOutFlags
+){
+  int rc;
+  sqlite3_file *pFile;
+  pFile = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile);
+  if( pFile ){
+    rc = sqlite3OsOpen(pVfs, zFile, pFile, flags, pOutFlags);
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(pFile);
+      *ppFile = 0;
+    }else{
+      *ppFile = pFile;
+    }
+  }else{
+    *ppFile = 0;
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  assert( *ppFile!=0 || rc!=SQLITE_OK );
+  return rc;
+}
+SQLITE_PRIVATE void sqlite3OsCloseFree(sqlite3_file *pFile){
+  assert( pFile );
+  sqlite3OsClose(pFile);
+  sqlite3_free(pFile);
+}
+
+/*
+** This function is a wrapper around the OS specific implementation of
+** sqlite3_os_init(). The purpose of the wrapper is to provide the
+** ability to simulate a malloc failure, so that the handling of an
+** error in sqlite3_os_init() by the upper layers can be tested.
+*/
+SQLITE_PRIVATE int sqlite3OsInit(void){
+  void *p = sqlite3_malloc(10);
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  sqlite3_free(p);
+  return sqlite3_os_init();
+}
+
+/*
+** The list of all registered VFS implementations.
+*/
+static sqlite3_vfs * SQLITE_WSD vfsList = 0;
+#define vfsList GLOBAL(sqlite3_vfs *, vfsList)
+
+/*
+** Locate a VFS by name.  If no name is given, simply return the
+** first VFS on the list.
+*/
+SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfs){
+  sqlite3_vfs *pVfs = 0;
+#if SQLITE_THREADSAFE
+  sqlite3_mutex *mutex;
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return 0;
+#endif
+#if SQLITE_THREADSAFE
+  mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+  sqlite3_mutex_enter(mutex);
+  for(pVfs = vfsList; pVfs; pVfs=pVfs->pNext){
+    if( zVfs==0 ) break;
+    if( strcmp(zVfs, pVfs->zName)==0 ) break;
+  }
+  sqlite3_mutex_leave(mutex);
+  return pVfs;
+}
+
+/*
+** Unlink a VFS from the linked list
+*/
+static void vfsUnlink(sqlite3_vfs *pVfs){
+  assert( sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN)) );
+  if( pVfs==0 ){
+    /* No-op */
+  }else if( vfsList==pVfs ){
+    vfsList = pVfs->pNext;
+  }else if( vfsList ){
+    sqlite3_vfs *p = vfsList;
+    while( p->pNext && p->pNext!=pVfs ){
+      p = p->pNext;
+    }
+    if( p->pNext==pVfs ){
+      p->pNext = pVfs->pNext;
+    }
+  }
+}
+
+/*
+** Register a VFS with the system.  It is harmless to register the same
+** VFS multiple times.  The new VFS becomes the default if makeDflt is
+** true.
+*/
+SQLITE_API int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){
+  MUTEX_LOGIC(sqlite3_mutex *mutex;)
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pVfs==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+
+  MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  sqlite3_mutex_enter(mutex);
+  vfsUnlink(pVfs);
+  if( makeDflt || vfsList==0 ){
+    pVfs->pNext = vfsList;
+    vfsList = pVfs;
+  }else{
+    pVfs->pNext = vfsList->pNext;
+    vfsList->pNext = pVfs;
+  }
+  assert(vfsList);
+  sqlite3_mutex_leave(mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Unregister a VFS so that it is no longer accessible.
+*/
+SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs *pVfs){
+  MUTEX_LOGIC(sqlite3_mutex *mutex;)
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+  MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  sqlite3_mutex_enter(mutex);
+  vfsUnlink(pVfs);
+  sqlite3_mutex_leave(mutex);
+  return SQLITE_OK;
+}
+
+/************** End of os.c **************************************************/
+/************** Begin file fault.c *******************************************/
+/*
+** 2008 Jan 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code to support the concept of "benign"
+** malloc failures (when the xMalloc() or xRealloc() method of the
+** sqlite3_mem_methods structure fails to allocate a block of memory
+** and returns 0).
+**
+** Most malloc failures are non-benign. After they occur, SQLite
+** abandons the current operation and returns an error code (usually
+** SQLITE_NOMEM) to the user. However, sometimes a fault is not necessarily
+** fatal. For example, if a malloc fails while resizing a hash table, this
+** is completely recoverable simply by not carrying out the resize. The
+** hash table will continue to function normally.  So a malloc failure
+** during a hash table resize is a benign fault.
+*/
+
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_UNTESTABLE
+
+/*
+** Global variables.
+*/
+typedef struct BenignMallocHooks BenignMallocHooks;
+static SQLITE_WSD struct BenignMallocHooks {
+  void (*xBenignBegin)(void);
+  void (*xBenignEnd)(void);
+} sqlite3Hooks = { 0, 0 };
+
+/* The "wsdHooks" macro will resolve to the appropriate BenignMallocHooks
+** structure.  If writable static data is unsupported on the target,
+** we have to locate the state vector at run-time.  In the more common
+** case where writable static data is supported, wsdHooks can refer directly
+** to the "sqlite3Hooks" state vector declared above.
+*/
+#ifdef SQLITE_OMIT_WSD
+# define wsdHooksInit \
+  BenignMallocHooks *x = &GLOBAL(BenignMallocHooks,sqlite3Hooks)
+# define wsdHooks x[0]
+#else
+# define wsdHooksInit
+# define wsdHooks sqlite3Hooks
+#endif
+
+
+/*
+** Register hooks to call when sqlite3BeginBenignMalloc() and
+** sqlite3EndBenignMalloc() are called, respectively.
+*/
+SQLITE_PRIVATE void sqlite3BenignMallocHooks(
+  void (*xBenignBegin)(void),
+  void (*xBenignEnd)(void)
+){
+  wsdHooksInit;
+  wsdHooks.xBenignBegin = xBenignBegin;
+  wsdHooks.xBenignEnd = xBenignEnd;
+}
+
+/*
+** This (sqlite3EndBenignMalloc()) is called by SQLite code to indicate that
+** subsequent malloc failures are benign. A call to sqlite3EndBenignMalloc()
+** indicates that subsequent malloc failures are non-benign.
+*/
+SQLITE_PRIVATE void sqlite3BeginBenignMalloc(void){
+  wsdHooksInit;
+  if( wsdHooks.xBenignBegin ){
+    wsdHooks.xBenignBegin();
+  }
+}
+SQLITE_PRIVATE void sqlite3EndBenignMalloc(void){
+  wsdHooksInit;
+  if( wsdHooks.xBenignEnd ){
+    wsdHooks.xBenignEnd();
+  }
+}
+
+#endif   /* #ifndef SQLITE_UNTESTABLE */
+
+/************** End of fault.c ***********************************************/
+/************** Begin file mem0.c ********************************************/
+/*
+** 2008 October 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains a no-op memory allocation drivers for use when
+** SQLITE_ZERO_MALLOC is defined.  The allocation drivers implemented
+** here always fail.  SQLite will not operate with these drivers.  These
+** are merely placeholders.  Real drivers must be substituted using
+** sqlite3_config() before SQLite will operate.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is the default.  It is
+** used when no other memory allocator is specified using compile-time
+** macros.
+*/
+#ifdef SQLITE_ZERO_MALLOC
+
+/*
+** No-op versions of all memory allocation routines
+*/
+static void *sqlite3MemMalloc(int nByte){ return 0; }
+static void sqlite3MemFree(void *pPrior){ return; }
+static void *sqlite3MemRealloc(void *pPrior, int nByte){ return 0; }
+static int sqlite3MemSize(void *pPrior){ return 0; }
+static int sqlite3MemRoundup(int n){ return n; }
+static int sqlite3MemInit(void *NotUsed){ return SQLITE_OK; }
+static void sqlite3MemShutdown(void *NotUsed){ return; }
+
+/*
+** This routine is the only routine in this file with external linkage.
+**
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file.
+*/
+SQLITE_PRIVATE void sqlite3MemSetDefault(void){
+  static const sqlite3_mem_methods defaultMethods = {
+     sqlite3MemMalloc,
+     sqlite3MemFree,
+     sqlite3MemRealloc,
+     sqlite3MemSize,
+     sqlite3MemRoundup,
+     sqlite3MemInit,
+     sqlite3MemShutdown,
+     0
+  };
+  sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods);
+}
+
+#endif /* SQLITE_ZERO_MALLOC */
+
+/************** End of mem0.c ************************************************/
+/************** Begin file mem1.c ********************************************/
+/*
+** 2007 August 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains low-level memory allocation drivers for when
+** SQLite will use the standard C-library malloc/realloc/free interface
+** to obtain the memory it needs.
+**
+** This file contains implementations of the low-level memory allocation
+** routines specified in the sqlite3_mem_methods object.  The content of
+** this file is only used if SQLITE_SYSTEM_MALLOC is defined.  The
+** SQLITE_SYSTEM_MALLOC macro is defined automatically if neither the
+** SQLITE_MEMDEBUG nor the SQLITE_WIN32_MALLOC macros are defined.  The
+** default configuration is to use memory allocation routines in this
+** file.
+**
+** C-preprocessor macro summary:
+**
+**    HAVE_MALLOC_USABLE_SIZE     The configure script sets this symbol if
+**                                the malloc_usable_size() interface exists
+**                                on the target platform.  Or, this symbol
+**                                can be set manually, if desired.
+**                                If an equivalent interface exists by
+**                                a different name, using a separate -D
+**                                option to rename it.
+**
+**    SQLITE_WITHOUT_ZONEMALLOC   Some older macs lack support for the zone
+**                                memory allocator.  Set this symbol to enable
+**                                building on older macs.
+**
+**    SQLITE_WITHOUT_MSIZE        Set this symbol to disable the use of
+**                                _msize() on windows systems.  This might
+**                                be necessary when compiling for Delphi,
+**                                for example.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is the default.  It is
+** used when no other memory allocator is specified using compile-time
+** macros.
+*/
+#ifdef SQLITE_SYSTEM_MALLOC
+#if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC)
+
+/*
+** Use the zone allocator available on apple products unless the
+** SQLITE_WITHOUT_ZONEMALLOC symbol is defined.
+*/
+#include <sys/sysctl.h>
+#include <malloc/malloc.h>
+#ifdef SQLITE_MIGHT_BE_SINGLE_CORE
+#include <libkern/OSAtomic.h>
+#endif /* SQLITE_MIGHT_BE_SINGLE_CORE */
+static malloc_zone_t* _sqliteZone_;
+#define SQLITE_MALLOC(x) malloc_zone_malloc(_sqliteZone_, (x))
+#define SQLITE_FREE(x) malloc_zone_free(_sqliteZone_, (x));
+#define SQLITE_REALLOC(x,y) malloc_zone_realloc(_sqliteZone_, (x), (y))
+#define SQLITE_MALLOCSIZE(x) \
+        (_sqliteZone_ ? _sqliteZone_->size(_sqliteZone_,x) : malloc_size(x))
+
+#else /* if not __APPLE__ */
+
+/*
+** Use standard C library malloc and free on non-Apple systems.
+** Also used by Apple systems if SQLITE_WITHOUT_ZONEMALLOC is defined.
+*/
+#define SQLITE_MALLOC(x)             malloc(x)
+#define SQLITE_FREE(x)               free(x)
+#define SQLITE_REALLOC(x,y)          realloc((x),(y))
+
+/*
+** The malloc.h header file is needed for malloc_usable_size() function
+** on some systems (e.g. Linux).
+*/
+#if HAVE_MALLOC_H && HAVE_MALLOC_USABLE_SIZE
+#  define SQLITE_USE_MALLOC_H 1
+#  define SQLITE_USE_MALLOC_USABLE_SIZE 1
+/*
+** The MSVCRT has malloc_usable_size(), but it is called _msize().  The
+** use of _msize() is automatic, but can be disabled by compiling with
+** -DSQLITE_WITHOUT_MSIZE.  Using the _msize() function also requires
+** the malloc.h header file.
+*/
+#elif defined(_MSC_VER) && !defined(SQLITE_WITHOUT_MSIZE)
+#  define SQLITE_USE_MALLOC_H
+#  define SQLITE_USE_MSIZE
+#endif
+
+/*
+** Include the malloc.h header file, if necessary.  Also set define macro
+** SQLITE_MALLOCSIZE to the appropriate function name, which is _msize()
+** for MSVC and malloc_usable_size() for most other systems (e.g. Linux).
+** The memory size function can always be overridden manually by defining
+** the macro SQLITE_MALLOCSIZE to the desired function name.
+*/
+#if defined(SQLITE_USE_MALLOC_H)
+#  include <malloc.h>
+#  if defined(SQLITE_USE_MALLOC_USABLE_SIZE)
+#    if !defined(SQLITE_MALLOCSIZE)
+#      define SQLITE_MALLOCSIZE(x)   malloc_usable_size(x)
+#    endif
+#  elif defined(SQLITE_USE_MSIZE)
+#    if !defined(SQLITE_MALLOCSIZE)
+#      define SQLITE_MALLOCSIZE      _msize
+#    endif
+#  endif
+#endif /* defined(SQLITE_USE_MALLOC_H) */
+
+#endif /* __APPLE__ or not __APPLE__ */
+
+/*
+** Like malloc(), but remember the size of the allocation
+** so that we can find it later using sqlite3MemSize().
+**
+** For this low-level routine, we are guaranteed that nByte>0 because
+** cases of nByte<=0 will be intercepted and dealt with by higher level
+** routines.
+*/
+static void *sqlite3MemMalloc(int nByte){
+#ifdef SQLITE_MALLOCSIZE
+  void *p;
+  testcase( ROUND8(nByte)==nByte );
+  p = SQLITE_MALLOC( nByte );
+  if( p==0 ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
+  }
+  return p;
+#else
+  sqlite3_int64 *p;
+  assert( nByte>0 );
+  testcase( ROUND8(nByte)!=nByte );
+  p = SQLITE_MALLOC( nByte+8 );
+  if( p ){
+    p[0] = nByte;
+    p++;
+  }else{
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
+  }
+  return (void *)p;
+#endif
+}
+
+/*
+** Like free() but works for allocations obtained from sqlite3MemMalloc()
+** or sqlite3MemRealloc().
+**
+** For this low-level routine, we already know that pPrior!=0 since
+** cases where pPrior==0 will have been intercepted and dealt with
+** by higher-level routines.
+*/
+static void sqlite3MemFree(void *pPrior){
+#ifdef SQLITE_MALLOCSIZE
+  SQLITE_FREE(pPrior);
+#else
+  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
+  assert( pPrior!=0 );
+  p--;
+  SQLITE_FREE(p);
+#endif
+}
+
+/*
+** Report the allocated size of a prior return from xMalloc()
+** or xRealloc().
+*/
+static int sqlite3MemSize(void *pPrior){
+#ifdef SQLITE_MALLOCSIZE
+  assert( pPrior!=0 );
+  return (int)SQLITE_MALLOCSIZE(pPrior);
+#else
+  sqlite3_int64 *p;
+  assert( pPrior!=0 );
+  p = (sqlite3_int64*)pPrior;
+  p--;
+  return (int)p[0];
+#endif
+}
+
+/*
+** Like realloc().  Resize an allocation previously obtained from
+** sqlite3MemMalloc().
+**
+** For this low-level interface, we know that pPrior!=0.  Cases where
+** pPrior==0 while have been intercepted by higher-level routine and
+** redirected to xMalloc.  Similarly, we know that nByte>0 because
+** cases where nByte<=0 will have been intercepted by higher-level
+** routines and redirected to xFree.
+*/
+static void *sqlite3MemRealloc(void *pPrior, int nByte){
+#ifdef SQLITE_MALLOCSIZE
+  void *p = SQLITE_REALLOC(pPrior, nByte);
+  if( p==0 ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM,
+      "failed memory resize %u to %u bytes",
+      SQLITE_MALLOCSIZE(pPrior), nByte);
+  }
+  return p;
+#else
+  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
+  assert( pPrior!=0 && nByte>0 );
+  assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */
+  p--;
+  p = SQLITE_REALLOC(p, nByte+8 );
+  if( p ){
+    p[0] = nByte;
+    p++;
+  }else{
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM,
+      "failed memory resize %u to %u bytes",
+      sqlite3MemSize(pPrior), nByte);
+  }
+  return (void*)p;
+#endif
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int sqlite3MemRoundup(int n){
+  return ROUND8(n);
+}
+
+/*
+** Initialize this module.
+*/
+static int sqlite3MemInit(void *NotUsed){
+#if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC)
+  int cpuCount;
+  size_t len;
+  if( _sqliteZone_ ){
+    return SQLITE_OK;
+  }
+  len = sizeof(cpuCount);
+  /* One usually wants to use hw.activecpu for MT decisions, but not here */
+  sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0);
+  if( cpuCount>1 ){
+    /* defer MT decisions to system malloc */
+    _sqliteZone_ = malloc_default_zone();
+  }else{
+    /* only 1 core, use our own zone to contention over global locks,
+    ** e.g. we have our own dedicated locks */
+    _sqliteZone_ = malloc_create_zone(4096, 0);
+    malloc_set_zone_name(_sqliteZone_, "Sqlite_Heap");
+  }
+#endif /*  defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC) */
+  UNUSED_PARAMETER(NotUsed);
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize this module.
+*/
+static void sqlite3MemShutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  return;
+}
+
+/*
+** This routine is the only routine in this file with external linkage.
+**
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file.
+*/
+SQLITE_PRIVATE void sqlite3MemSetDefault(void){
+  static const sqlite3_mem_methods defaultMethods = {
+     sqlite3MemMalloc,
+     sqlite3MemFree,
+     sqlite3MemRealloc,
+     sqlite3MemSize,
+     sqlite3MemRoundup,
+     sqlite3MemInit,
+     sqlite3MemShutdown,
+     0
+  };
+  sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods);
+}
+
+#endif /* SQLITE_SYSTEM_MALLOC */
+
+/************** End of mem1.c ************************************************/
+/************** Begin file mem2.c ********************************************/
+/*
+** 2007 August 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains low-level memory allocation drivers for when
+** SQLite will use the standard C-library malloc/realloc/free interface
+** to obtain the memory it needs while adding lots of additional debugging
+** information to each allocation in order to help detect and fix memory
+** leaks and memory usage errors.
+**
+** This file contains implementations of the low-level memory allocation
+** routines specified in the sqlite3_mem_methods object.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is used only if the
+** SQLITE_MEMDEBUG macro is defined
+*/
+#ifdef SQLITE_MEMDEBUG
+
+/*
+** The backtrace functionality is only available with GLIBC
+*/
+#ifdef __GLIBC__
+  extern int backtrace(void**,int);
+  extern void backtrace_symbols_fd(void*const*,int,int);
+#else
+# define backtrace(A,B) 1
+# define backtrace_symbols_fd(A,B,C)
+#endif
+/* #include <stdio.h> */
+
+/*
+** Each memory allocation looks like this:
+**
+**  ------------------------------------------------------------------------
+**  | Title |  backtrace pointers |  MemBlockHdr |  allocation |  EndGuard |
+**  ------------------------------------------------------------------------
+**
+** The application code sees only a pointer to the allocation.  We have
+** to back up from the allocation pointer to find the MemBlockHdr.  The
+** MemBlockHdr tells us the size of the allocation and the number of
+** backtrace pointers.  There is also a guard word at the end of the
+** MemBlockHdr.
+*/
+struct MemBlockHdr {
+  i64 iSize;                          /* Size of this allocation */
+  struct MemBlockHdr *pNext, *pPrev;  /* Linked list of all unfreed memory */
+  char nBacktrace;                    /* Number of backtraces on this alloc */
+  char nBacktraceSlots;               /* Available backtrace slots */
+  u8 nTitle;                          /* Bytes of title; includes '\0' */
+  u8 eType;                           /* Allocation type code */
+  int iForeGuard;                     /* Guard word for sanity */
+};
+
+/*
+** Guard words
+*/
+#define FOREGUARD 0x80F5E153
+#define REARGUARD 0xE4676B53
+
+/*
+** Number of malloc size increments to track.
+*/
+#define NCSIZE  1000
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static struct {
+
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+
+  /*
+  ** Head and tail of a linked list of all outstanding allocations
+  */
+  struct MemBlockHdr *pFirst;
+  struct MemBlockHdr *pLast;
+
+  /*
+  ** The number of levels of backtrace to save in new allocations.
+  */
+  int nBacktrace;
+  void (*xBacktrace)(int, int, void **);
+
+  /*
+  ** Title text to insert in front of each block
+  */
+  int nTitle;        /* Bytes of zTitle to save.  Includes '\0' and padding */
+  char zTitle[100];  /* The title text */
+
+  /*
+  ** sqlite3MallocDisallow() increments the following counter.
+  ** sqlite3MallocAllow() decrements it.
+  */
+  int disallow; /* Do not allow memory allocation */
+
+  /*
+  ** Gather statistics on the sizes of memory allocations.
+  ** nAlloc[i] is the number of allocation attempts of i*8
+  ** bytes.  i==NCSIZE is the number of allocation attempts for
+  ** sizes more than NCSIZE*8 bytes.
+  */
+  int nAlloc[NCSIZE];      /* Total number of allocations */
+  int nCurrent[NCSIZE];    /* Current number of allocations */
+  int mxCurrent[NCSIZE];   /* Highwater mark for nCurrent */
+
+} mem;
+
+
+/*
+** Adjust memory usage statistics
+*/
+static void adjustStats(int iSize, int increment){
+  int i = ROUND8(iSize)/8;
+  if( i>NCSIZE-1 ){
+    i = NCSIZE - 1;
+  }
+  if( increment>0 ){
+    mem.nAlloc[i]++;
+    mem.nCurrent[i]++;
+    if( mem.nCurrent[i]>mem.mxCurrent[i] ){
+      mem.mxCurrent[i] = mem.nCurrent[i];
+    }
+  }else{
+    mem.nCurrent[i]--;
+    assert( mem.nCurrent[i]>=0 );
+  }
+}
+
+/*
+** Given an allocation, find the MemBlockHdr for that allocation.
+**
+** This routine checks the guards at either end of the allocation and
+** if they are incorrect it asserts.
+*/
+static struct MemBlockHdr *sqlite3MemsysGetHeader(const void *pAllocation){
+  struct MemBlockHdr *p;
+  int *pInt;
+  u8 *pU8;
+  int nReserve;
+
+  p = (struct MemBlockHdr*)pAllocation;
+  p--;
+  assert( p->iForeGuard==(int)FOREGUARD );
+  nReserve = ROUND8(p->iSize);
+  pInt = (int*)pAllocation;
+  pU8 = (u8*)pAllocation;
+  assert( pInt[nReserve/sizeof(int)]==(int)REARGUARD );
+  /* This checks any of the "extra" bytes allocated due
+  ** to rounding up to an 8 byte boundary to ensure
+  ** they haven't been overwritten.
+  */
+  while( nReserve-- > p->iSize ) assert( pU8[nReserve]==0x65 );
+  return p;
+}
+
+/*
+** Return the number of bytes currently allocated at address p.
+*/
+static int sqlite3MemSize(void *p){
+  struct MemBlockHdr *pHdr;
+  if( !p ){
+    return 0;
+  }
+  pHdr = sqlite3MemsysGetHeader(p);
+  return (int)pHdr->iSize;
+}
+
+/*
+** Initialize the memory allocation subsystem.
+*/
+static int sqlite3MemInit(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  assert( (sizeof(struct MemBlockHdr)&7) == 0 );
+  if( !sqlite3GlobalConfig.bMemstat ){
+    /* If memory status is enabled, then the malloc.c wrapper will already
+    ** hold the STATIC_MEM mutex when the routines here are invoked. */
+    mem.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize the memory allocation subsystem.
+*/
+static void sqlite3MemShutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  mem.mutex = 0;
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int sqlite3MemRoundup(int n){
+  return ROUND8(n);
+}
+
+/*
+** Fill a buffer with pseudo-random bytes.  This is used to preset
+** the content of a new memory allocation to unpredictable values and
+** to clear the content of a freed allocation to unpredictable values.
+*/
+static void randomFill(char *pBuf, int nByte){
+  unsigned int x, y, r;
+  x = SQLITE_PTR_TO_INT(pBuf);
+  y = nByte | 1;
+  while( nByte >= 4 ){
+    x = (x>>1) ^ (-(int)(x&1) & 0xd0000001);
+    y = y*1103515245 + 12345;
+    r = x ^ y;
+    *(int*)pBuf = r;
+    pBuf += 4;
+    nByte -= 4;
+  }
+  while( nByte-- > 0 ){
+    x = (x>>1) ^ (-(int)(x&1) & 0xd0000001);
+    y = y*1103515245 + 12345;
+    r = x ^ y;
+    *(pBuf++) = r & 0xff;
+  }
+}
+
+/*
+** Allocate nByte bytes of memory.
+*/
+static void *sqlite3MemMalloc(int nByte){
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  char *z;
+  int *pInt;
+  void *p = 0;
+  int totalSize;
+  int nReserve;
+  sqlite3_mutex_enter(mem.mutex);
+  assert( mem.disallow==0 );
+  nReserve = ROUND8(nByte);
+  totalSize = nReserve + sizeof(*pHdr) + sizeof(int) +
+               mem.nBacktrace*sizeof(void*) + mem.nTitle;
+  p = malloc(totalSize);
+  if( p ){
+    z = p;
+    pBt = (void**)&z[mem.nTitle];
+    pHdr = (struct MemBlockHdr*)&pBt[mem.nBacktrace];
+    pHdr->pNext = 0;
+    pHdr->pPrev = mem.pLast;
+    if( mem.pLast ){
+      mem.pLast->pNext = pHdr;
+    }else{
+      mem.pFirst = pHdr;
+    }
+    mem.pLast = pHdr;
+    pHdr->iForeGuard = FOREGUARD;
+    pHdr->eType = MEMTYPE_HEAP;
+    pHdr->nBacktraceSlots = mem.nBacktrace;
+    pHdr->nTitle = mem.nTitle;
+    if( mem.nBacktrace ){
+      void *aAddr[40];
+      pHdr->nBacktrace = backtrace(aAddr, mem.nBacktrace+1)-1;
+      memcpy(pBt, &aAddr[1], pHdr->nBacktrace*sizeof(void*));
+      assert(pBt[0]);
+      if( mem.xBacktrace ){
+        mem.xBacktrace(nByte, pHdr->nBacktrace-1, &aAddr[1]);
+      }
+    }else{
+      pHdr->nBacktrace = 0;
+    }
+    if( mem.nTitle ){
+      memcpy(z, mem.zTitle, mem.nTitle);
+    }
+    pHdr->iSize = nByte;
+    adjustStats(nByte, +1);
+    pInt = (int*)&pHdr[1];
+    pInt[nReserve/sizeof(int)] = REARGUARD;
+    randomFill((char*)pInt, nByte);
+    memset(((char*)pInt)+nByte, 0x65, nReserve-nByte);
+    p = (void*)pInt;
+  }
+  sqlite3_mutex_leave(mem.mutex);
+  return p;
+}
+
+/*
+** Free memory.
+*/
+static void sqlite3MemFree(void *pPrior){
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  char *z;
+  assert( sqlite3GlobalConfig.bMemstat || sqlite3GlobalConfig.bCoreMutex==0
+       || mem.mutex!=0 );
+  pHdr = sqlite3MemsysGetHeader(pPrior);
+  pBt = (void**)pHdr;
+  pBt -= pHdr->nBacktraceSlots;
+  sqlite3_mutex_enter(mem.mutex);
+  if( pHdr->pPrev ){
+    assert( pHdr->pPrev->pNext==pHdr );
+    pHdr->pPrev->pNext = pHdr->pNext;
+  }else{
+    assert( mem.pFirst==pHdr );
+    mem.pFirst = pHdr->pNext;
+  }
+  if( pHdr->pNext ){
+    assert( pHdr->pNext->pPrev==pHdr );
+    pHdr->pNext->pPrev = pHdr->pPrev;
+  }else{
+    assert( mem.pLast==pHdr );
+    mem.pLast = pHdr->pPrev;
+  }
+  z = (char*)pBt;
+  z -= pHdr->nTitle;
+  adjustStats((int)pHdr->iSize, -1);
+  randomFill(z, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
+                (int)pHdr->iSize + sizeof(int) + pHdr->nTitle);
+  free(z);
+  sqlite3_mutex_leave(mem.mutex);
+}
+
+/*
+** Change the size of an existing memory allocation.
+**
+** For this debugging implementation, we *always* make a copy of the
+** allocation into a new place in memory.  In this way, if the
+** higher level code is using pointer to the old allocation, it is
+** much more likely to break and we are much more liking to find
+** the error.
+*/
+static void *sqlite3MemRealloc(void *pPrior, int nByte){
+  struct MemBlockHdr *pOldHdr;
+  void *pNew;
+  assert( mem.disallow==0 );
+  assert( (nByte & 7)==0 );     /* EV: R-46199-30249 */
+  pOldHdr = sqlite3MemsysGetHeader(pPrior);
+  pNew = sqlite3MemMalloc(nByte);
+  if( pNew ){
+    memcpy(pNew, pPrior, (int)(nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize));
+    if( nByte>pOldHdr->iSize ){
+      randomFill(&((char*)pNew)[pOldHdr->iSize], nByte - (int)pOldHdr->iSize);
+    }
+    sqlite3MemFree(pPrior);
+  }
+  return pNew;
+}
+
+/*
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file.
+*/
+SQLITE_PRIVATE void sqlite3MemSetDefault(void){
+  static const sqlite3_mem_methods defaultMethods = {
+     sqlite3MemMalloc,
+     sqlite3MemFree,
+     sqlite3MemRealloc,
+     sqlite3MemSize,
+     sqlite3MemRoundup,
+     sqlite3MemInit,
+     sqlite3MemShutdown,
+     0
+  };
+  sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods);
+}
+
+/*
+** Set the "type" of an allocation.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugSetType(void *p, u8 eType){
+  if( p && sqlite3GlobalConfig.m.xFree==sqlite3MemFree ){
+    struct MemBlockHdr *pHdr;
+    pHdr = sqlite3MemsysGetHeader(p);
+    assert( pHdr->iForeGuard==FOREGUARD );
+    pHdr->eType = eType;
+  }
+}
+
+/*
+** Return TRUE if the mask of type in eType matches the type of the
+** allocation p.  Also return true if p==NULL.
+**
+** This routine is designed for use within an assert() statement, to
+** verify the type of an allocation.  For example:
+**
+**     assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+*/
+SQLITE_PRIVATE int sqlite3MemdebugHasType(const void *p, u8 eType){
+  int rc = 1;
+  if( p && sqlite3GlobalConfig.m.xFree==sqlite3MemFree ){
+    struct MemBlockHdr *pHdr;
+    pHdr = sqlite3MemsysGetHeader(p);
+    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */
+    if( (pHdr->eType&eType)==0 ){
+      rc = 0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Return TRUE if the mask of type in eType matches no bits of the type of the
+** allocation p.  Also return true if p==NULL.
+**
+** This routine is designed for use within an assert() statement, to
+** verify the type of an allocation.  For example:
+**
+**     assert( sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
+*/
+SQLITE_PRIVATE int sqlite3MemdebugNoType(const void *p, u8 eType){
+  int rc = 1;
+  if( p && sqlite3GlobalConfig.m.xFree==sqlite3MemFree ){
+    struct MemBlockHdr *pHdr;
+    pHdr = sqlite3MemsysGetHeader(p);
+    assert( pHdr->iForeGuard==FOREGUARD );         /* Allocation is valid */
+    if( (pHdr->eType&eType)!=0 ){
+      rc = 0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Set the number of backtrace levels kept for each allocation.
+** A value of zero turns off backtracing.  The number is always rounded
+** up to a multiple of 2.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugBacktrace(int depth){
+  if( depth<0 ){ depth = 0; }
+  if( depth>20 ){ depth = 20; }
+  depth = (depth+1)&0xfe;
+  mem.nBacktrace = depth;
+}
+
+SQLITE_PRIVATE void sqlite3MemdebugBacktraceCallback(void (*xBacktrace)(int, int, void **)){
+  mem.xBacktrace = xBacktrace;
+}
+
+/*
+** Set the title string for subsequent allocations.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugSettitle(const char *zTitle){
+  unsigned int n = sqlite3Strlen30(zTitle) + 1;
+  sqlite3_mutex_enter(mem.mutex);
+  if( n>=sizeof(mem.zTitle) ) n = sizeof(mem.zTitle)-1;
+  memcpy(mem.zTitle, zTitle, n);
+  mem.zTitle[n] = 0;
+  mem.nTitle = ROUND8(n);
+  sqlite3_mutex_leave(mem.mutex);
+}
+
+SQLITE_PRIVATE void sqlite3MemdebugSync(){
+  struct MemBlockHdr *pHdr;
+  for(pHdr=mem.pFirst; pHdr; pHdr=pHdr->pNext){
+    void **pBt = (void**)pHdr;
+    pBt -= pHdr->nBacktraceSlots;
+    mem.xBacktrace((int)pHdr->iSize, pHdr->nBacktrace-1, &pBt[1]);
+  }
+}
+
+/*
+** Open the file indicated and write a log of all unfreed memory
+** allocations into that log.
+*/
+SQLITE_PRIVATE void sqlite3MemdebugDump(const char *zFilename){
+  FILE *out;
+  struct MemBlockHdr *pHdr;
+  void **pBt;
+  int i;
+  out = fopen(zFilename, "w");
+  if( out==0 ){
+    fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                    zFilename);
+    return;
+  }
+  for(pHdr=mem.pFirst; pHdr; pHdr=pHdr->pNext){
+    char *z = (char*)pHdr;
+    z -= pHdr->nBacktraceSlots*sizeof(void*) + pHdr->nTitle;
+    fprintf(out, "**** %lld bytes at %p from %s ****\n",
+            pHdr->iSize, &pHdr[1], pHdr->nTitle ? z : "???");
+    if( pHdr->nBacktrace ){
+      fflush(out);
+      pBt = (void**)pHdr;
+      pBt -= pHdr->nBacktraceSlots;
+      backtrace_symbols_fd(pBt, pHdr->nBacktrace, fileno(out));
+      fprintf(out, "\n");
+    }
+  }
+  fprintf(out, "COUNTS:\n");
+  for(i=0; i<NCSIZE-1; i++){
+    if( mem.nAlloc[i] ){
+      fprintf(out, "   %5d: %10d %10d %10d\n",
+            i*8, mem.nAlloc[i], mem.nCurrent[i], mem.mxCurrent[i]);
+    }
+  }
+  if( mem.nAlloc[NCSIZE-1] ){
+    fprintf(out, "   %5d: %10d %10d %10d\n",
+             NCSIZE*8-8, mem.nAlloc[NCSIZE-1],
+             mem.nCurrent[NCSIZE-1], mem.mxCurrent[NCSIZE-1]);
+  }
+  fclose(out);
+}
+
+/*
+** Return the number of times sqlite3MemMalloc() has been called.
+*/
+SQLITE_PRIVATE int sqlite3MemdebugMallocCount(){
+  int i;
+  int nTotal = 0;
+  for(i=0; i<NCSIZE; i++){
+    nTotal += mem.nAlloc[i];
+  }
+  return nTotal;
+}
+
+
+#endif /* SQLITE_MEMDEBUG */
+
+/************** End of mem2.c ************************************************/
+/************** Begin file mem3.c ********************************************/
+/*
+** 2007 October 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement a memory
+** allocation subsystem for use by SQLite.
+**
+** This version of the memory allocation subsystem omits all
+** use of malloc(). The SQLite user supplies a block of memory
+** before calling sqlite3_initialize() from which allocations
+** are made and returned by the xMalloc() and xRealloc()
+** implementations. Once sqlite3_initialize() has been called,
+** the amount of memory available to SQLite is fixed and cannot
+** be changed.
+**
+** This version of the memory allocation subsystem is included
+** in the build only if SQLITE_ENABLE_MEMSYS3 is defined.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is only built into the library
+** SQLITE_ENABLE_MEMSYS3 is defined. Defining this symbol does not
+** mean that the library will use a memory-pool by default, just that
+** it is available. The mempool allocator is activated by calling
+** sqlite3_config().
+*/
+#ifdef SQLITE_ENABLE_MEMSYS3
+
+/*
+** Maximum size (in Mem3Blocks) of a "small" chunk.
+*/
+#define MX_SMALL 10
+
+
+/*
+** Number of freelist hash slots
+*/
+#define N_HASH  61
+
+/*
+** A memory allocation (also called a "chunk") consists of two or
+** more blocks where each block is 8 bytes.  The first 8 bytes are
+** a header that is not returned to the user.
+**
+** A chunk is two or more blocks that is either checked out or
+** free.  The first block has format u.hdr.  u.hdr.size4x is 4 times the
+** size of the allocation in blocks if the allocation is free.
+** The u.hdr.size4x&1 bit is true if the chunk is checked out and
+** false if the chunk is on the freelist.  The u.hdr.size4x&2 bit
+** is true if the previous chunk is checked out and false if the
+** previous chunk is free.  The u.hdr.prevSize field is the size of
+** the previous chunk in blocks if the previous chunk is on the
+** freelist. If the previous chunk is checked out, then
+** u.hdr.prevSize can be part of the data for that chunk and should
+** not be read or written.
+**
+** We often identify a chunk by its index in mem3.aPool[].  When
+** this is done, the chunk index refers to the second block of
+** the chunk.  In this way, the first chunk has an index of 1.
+** A chunk index of 0 means "no such chunk" and is the equivalent
+** of a NULL pointer.
+**
+** The second block of free chunks is of the form u.list.  The
+** two fields form a double-linked list of chunks of related sizes.
+** Pointers to the head of the list are stored in mem3.aiSmall[]
+** for smaller chunks and mem3.aiHash[] for larger chunks.
+**
+** The second block of a chunk is user data if the chunk is checked
+** out.  If a chunk is checked out, the user data may extend into
+** the u.hdr.prevSize value of the following chunk.
+*/
+typedef struct Mem3Block Mem3Block;
+struct Mem3Block {
+  union {
+    struct {
+      u32 prevSize;   /* Size of previous chunk in Mem3Block elements */
+      u32 size4x;     /* 4x the size of current chunk in Mem3Block elements */
+    } hdr;
+    struct {
+      u32 next;       /* Index in mem3.aPool[] of next free chunk */
+      u32 prev;       /* Index in mem3.aPool[] of previous free chunk */
+    } list;
+  } u;
+};
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem3".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static SQLITE_WSD struct Mem3Global {
+  /*
+  ** Memory available for allocation. nPool is the size of the array
+  ** (in Mem3Blocks) pointed to by aPool less 2.
+  */
+  u32 nPool;
+  Mem3Block *aPool;
+
+  /*
+  ** True if we are evaluating an out-of-memory callback.
+  */
+  int alarmBusy;
+
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+
+  /*
+  ** The minimum amount of free space that we have seen.
+  */
+  u32 mnKeyBlk;
+
+  /*
+  ** iKeyBlk is the index of the key chunk.  Most new allocations
+  ** occur off of this chunk.  szKeyBlk is the size (in Mem3Blocks)
+  ** of the current key chunk.  iKeyBlk is 0 if there is no key chunk.
+  ** The key chunk is not in either the aiHash[] or aiSmall[].
+  */
+  u32 iKeyBlk;
+  u32 szKeyBlk;
+
+  /*
+  ** Array of lists of free blocks according to the block size
+  ** for smaller chunks, or a hash on the block size for larger
+  ** chunks.
+  */
+  u32 aiSmall[MX_SMALL-1];   /* For sizes 2 through MX_SMALL, inclusive */
+  u32 aiHash[N_HASH];        /* For sizes MX_SMALL+1 and larger */
+} mem3 = { 97535575 };
+
+#define mem3 GLOBAL(struct Mem3Global, mem3)
+
+/*
+** Unlink the chunk at mem3.aPool[i] from list it is currently
+** on.  *pRoot is the list that i is a member of.
+*/
+static void memsys3UnlinkFromList(u32 i, u32 *pRoot){
+  u32 next = mem3.aPool[i].u.list.next;
+  u32 prev = mem3.aPool[i].u.list.prev;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  if( prev==0 ){
+    *pRoot = next;
+  }else{
+    mem3.aPool[prev].u.list.next = next;
+  }
+  if( next ){
+    mem3.aPool[next].u.list.prev = prev;
+  }
+  mem3.aPool[i].u.list.next = 0;
+  mem3.aPool[i].u.list.prev = 0;
+}
+
+/*
+** Unlink the chunk at index i from
+** whatever list is currently a member of.
+*/
+static void memsys3Unlink(u32 i){
+  u32 size, hash;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( (mem3.aPool[i-1].u.hdr.size4x & 1)==0 );
+  assert( i>=1 );
+  size = mem3.aPool[i-1].u.hdr.size4x/4;
+  assert( size==mem3.aPool[i+size-1].u.hdr.prevSize );
+  assert( size>=2 );
+  if( size <= MX_SMALL ){
+    memsys3UnlinkFromList(i, &mem3.aiSmall[size-2]);
+  }else{
+    hash = size % N_HASH;
+    memsys3UnlinkFromList(i, &mem3.aiHash[hash]);
+  }
+}
+
+/*
+** Link the chunk at mem3.aPool[i] so that is on the list rooted
+** at *pRoot.
+*/
+static void memsys3LinkIntoList(u32 i, u32 *pRoot){
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  mem3.aPool[i].u.list.next = *pRoot;
+  mem3.aPool[i].u.list.prev = 0;
+  if( *pRoot ){
+    mem3.aPool[*pRoot].u.list.prev = i;
+  }
+  *pRoot = i;
+}
+
+/*
+** Link the chunk at index i into either the appropriate
+** small chunk list, or into the large chunk hash table.
+*/
+static void memsys3Link(u32 i){
+  u32 size, hash;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( i>=1 );
+  assert( (mem3.aPool[i-1].u.hdr.size4x & 1)==0 );
+  size = mem3.aPool[i-1].u.hdr.size4x/4;
+  assert( size==mem3.aPool[i+size-1].u.hdr.prevSize );
+  assert( size>=2 );
+  if( size <= MX_SMALL ){
+    memsys3LinkIntoList(i, &mem3.aiSmall[size-2]);
+  }else{
+    hash = size % N_HASH;
+    memsys3LinkIntoList(i, &mem3.aiHash[hash]);
+  }
+}
+
+/*
+** If the STATIC_MEM mutex is not already held, obtain it now. The mutex
+** will already be held (obtained by code in malloc.c) if
+** sqlite3GlobalConfig.bMemStat is true.
+*/
+static void memsys3Enter(void){
+  if( sqlite3GlobalConfig.bMemstat==0 && mem3.mutex==0 ){
+    mem3.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+  sqlite3_mutex_enter(mem3.mutex);
+}
+static void memsys3Leave(void){
+  sqlite3_mutex_leave(mem3.mutex);
+}
+
+/*
+** Called when we are unable to satisfy an allocation of nBytes.
+*/
+static void memsys3OutOfMemory(int nByte){
+  if( !mem3.alarmBusy ){
+    mem3.alarmBusy = 1;
+    assert( sqlite3_mutex_held(mem3.mutex) );
+    sqlite3_mutex_leave(mem3.mutex);
+    sqlite3_release_memory(nByte);
+    sqlite3_mutex_enter(mem3.mutex);
+    mem3.alarmBusy = 0;
+  }
+}
+
+
+/*
+** Chunk i is a free chunk that has been unlinked.  Adjust its
+** size parameters for check-out and return a pointer to the
+** user portion of the chunk.
+*/
+static void *memsys3Checkout(u32 i, u32 nBlock){
+  u32 x;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( i>=1 );
+  assert( mem3.aPool[i-1].u.hdr.size4x/4==nBlock );
+  assert( mem3.aPool[i+nBlock-1].u.hdr.prevSize==nBlock );
+  x = mem3.aPool[i-1].u.hdr.size4x;
+  mem3.aPool[i-1].u.hdr.size4x = nBlock*4 | 1 | (x&2);
+  mem3.aPool[i+nBlock-1].u.hdr.prevSize = nBlock;
+  mem3.aPool[i+nBlock-1].u.hdr.size4x |= 2;
+  return &mem3.aPool[i];
+}
+
+/*
+** Carve a piece off of the end of the mem3.iKeyBlk free chunk.
+** Return a pointer to the new allocation.  Or, if the key chunk
+** is not large enough, return 0.
+*/
+static void *memsys3FromKeyBlk(u32 nBlock){
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( mem3.szKeyBlk>=nBlock );
+  if( nBlock>=mem3.szKeyBlk-1 ){
+    /* Use the entire key chunk */
+    void *p = memsys3Checkout(mem3.iKeyBlk, mem3.szKeyBlk);
+    mem3.iKeyBlk = 0;
+    mem3.szKeyBlk = 0;
+    mem3.mnKeyBlk = 0;
+    return p;
+  }else{
+    /* Split the key block.  Return the tail. */
+    u32 newi, x;
+    newi = mem3.iKeyBlk + mem3.szKeyBlk - nBlock;
+    assert( newi > mem3.iKeyBlk+1 );
+    mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.prevSize = nBlock;
+    mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.size4x |= 2;
+    mem3.aPool[newi-1].u.hdr.size4x = nBlock*4 + 1;
+    mem3.szKeyBlk -= nBlock;
+    mem3.aPool[newi-1].u.hdr.prevSize = mem3.szKeyBlk;
+    x = mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x & 2;
+    mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x = mem3.szKeyBlk*4 | x;
+    if( mem3.szKeyBlk < mem3.mnKeyBlk ){
+      mem3.mnKeyBlk = mem3.szKeyBlk;
+    }
+    return (void*)&mem3.aPool[newi];
+  }
+}
+
+/*
+** *pRoot is the head of a list of free chunks of the same size
+** or same size hash.  In other words, *pRoot is an entry in either
+** mem3.aiSmall[] or mem3.aiHash[].
+**
+** This routine examines all entries on the given list and tries
+** to coalesce each entries with adjacent free chunks.
+**
+** If it sees a chunk that is larger than mem3.iKeyBlk, it replaces
+** the current mem3.iKeyBlk with the new larger chunk.  In order for
+** this mem3.iKeyBlk replacement to work, the key chunk must be
+** linked into the hash tables.  That is not the normal state of
+** affairs, of course.  The calling routine must link the key
+** chunk before invoking this routine, then must unlink the (possibly
+** changed) key chunk once this routine has finished.
+*/
+static void memsys3Merge(u32 *pRoot){
+  u32 iNext, prev, size, i, x;
+
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  for(i=*pRoot; i>0; i=iNext){
+    iNext = mem3.aPool[i].u.list.next;
+    size = mem3.aPool[i-1].u.hdr.size4x;
+    assert( (size&1)==0 );
+    if( (size&2)==0 ){
+      memsys3UnlinkFromList(i, pRoot);
+      assert( i > mem3.aPool[i-1].u.hdr.prevSize );
+      prev = i - mem3.aPool[i-1].u.hdr.prevSize;
+      if( prev==iNext ){
+        iNext = mem3.aPool[prev].u.list.next;
+      }
+      memsys3Unlink(prev);
+      size = i + size/4 - prev;
+      x = mem3.aPool[prev-1].u.hdr.size4x & 2;
+      mem3.aPool[prev-1].u.hdr.size4x = size*4 | x;
+      mem3.aPool[prev+size-1].u.hdr.prevSize = size;
+      memsys3Link(prev);
+      i = prev;
+    }else{
+      size /= 4;
+    }
+    if( size>mem3.szKeyBlk ){
+      mem3.iKeyBlk = i;
+      mem3.szKeyBlk = size;
+    }
+  }
+}
+
+/*
+** Return a block of memory of at least nBytes in size.
+** Return NULL if unable.
+**
+** This function assumes that the necessary mutexes, if any, are
+** already held by the caller. Hence "Unsafe".
+*/
+static void *memsys3MallocUnsafe(int nByte){
+  u32 i;
+  u32 nBlock;
+  u32 toFree;
+
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( sizeof(Mem3Block)==8 );
+  if( nByte<=12 ){
+    nBlock = 2;
+  }else{
+    nBlock = (nByte + 11)/8;
+  }
+  assert( nBlock>=2 );
+
+  /* STEP 1:
+  ** Look for an entry of the correct size in either the small
+  ** chunk table or in the large chunk hash table.  This is
+  ** successful most of the time (about 9 times out of 10).
+  */
+  if( nBlock <= MX_SMALL ){
+    i = mem3.aiSmall[nBlock-2];
+    if( i>0 ){
+      memsys3UnlinkFromList(i, &mem3.aiSmall[nBlock-2]);
+      return memsys3Checkout(i, nBlock);
+    }
+  }else{
+    int hash = nBlock % N_HASH;
+    for(i=mem3.aiHash[hash]; i>0; i=mem3.aPool[i].u.list.next){
+      if( mem3.aPool[i-1].u.hdr.size4x/4==nBlock ){
+        memsys3UnlinkFromList(i, &mem3.aiHash[hash]);
+        return memsys3Checkout(i, nBlock);
+      }
+    }
+  }
+
+  /* STEP 2:
+  ** Try to satisfy the allocation by carving a piece off of the end
+  ** of the key chunk.  This step usually works if step 1 fails.
+  */
+  if( mem3.szKeyBlk>=nBlock ){
+    return memsys3FromKeyBlk(nBlock);
+  }
+
+
+  /* STEP 3:
+  ** Loop through the entire memory pool.  Coalesce adjacent free
+  ** chunks.  Recompute the key chunk as the largest free chunk.
+  ** Then try again to satisfy the allocation by carving a piece off
+  ** of the end of the key chunk.  This step happens very
+  ** rarely (we hope!)
+  */
+  for(toFree=nBlock*16; toFree<(mem3.nPool*16); toFree *= 2){
+    memsys3OutOfMemory(toFree);
+    if( mem3.iKeyBlk ){
+      memsys3Link(mem3.iKeyBlk);
+      mem3.iKeyBlk = 0;
+      mem3.szKeyBlk = 0;
+    }
+    for(i=0; i<N_HASH; i++){
+      memsys3Merge(&mem3.aiHash[i]);
+    }
+    for(i=0; i<MX_SMALL-1; i++){
+      memsys3Merge(&mem3.aiSmall[i]);
+    }
+    if( mem3.szKeyBlk ){
+      memsys3Unlink(mem3.iKeyBlk);
+      if( mem3.szKeyBlk>=nBlock ){
+        return memsys3FromKeyBlk(nBlock);
+      }
+    }
+  }
+
+  /* If none of the above worked, then we fail. */
+  return 0;
+}
+
+/*
+** Free an outstanding memory allocation.
+**
+** This function assumes that the necessary mutexes, if any, are
+** already held by the caller. Hence "Unsafe".
+*/
+static void memsys3FreeUnsafe(void *pOld){
+  Mem3Block *p = (Mem3Block*)pOld;
+  int i;
+  u32 size, x;
+  assert( sqlite3_mutex_held(mem3.mutex) );
+  assert( p>mem3.aPool && p<&mem3.aPool[mem3.nPool] );
+  i = p - mem3.aPool;
+  assert( (mem3.aPool[i-1].u.hdr.size4x&1)==1 );
+  size = mem3.aPool[i-1].u.hdr.size4x/4;
+  assert( i+size<=mem3.nPool+1 );
+  mem3.aPool[i-1].u.hdr.size4x &= ~1;
+  mem3.aPool[i+size-1].u.hdr.prevSize = size;
+  mem3.aPool[i+size-1].u.hdr.size4x &= ~2;
+  memsys3Link(i);
+
+  /* Try to expand the key using the newly freed chunk */
+  if( mem3.iKeyBlk ){
+    while( (mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x&2)==0 ){
+      size = mem3.aPool[mem3.iKeyBlk-1].u.hdr.prevSize;
+      mem3.iKeyBlk -= size;
+      mem3.szKeyBlk += size;
+      memsys3Unlink(mem3.iKeyBlk);
+      x = mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x & 2;
+      mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x = mem3.szKeyBlk*4 | x;
+      mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.prevSize = mem3.szKeyBlk;
+    }
+    x = mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x & 2;
+    while( (mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.size4x&1)==0 ){
+      memsys3Unlink(mem3.iKeyBlk+mem3.szKeyBlk);
+      mem3.szKeyBlk += mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.size4x/4;
+      mem3.aPool[mem3.iKeyBlk-1].u.hdr.size4x = mem3.szKeyBlk*4 | x;
+      mem3.aPool[mem3.iKeyBlk+mem3.szKeyBlk-1].u.hdr.prevSize = mem3.szKeyBlk;
+    }
+  }
+}
+
+/*
+** Return the size of an outstanding allocation, in bytes.  The
+** size returned omits the 8-byte header overhead.  This only
+** works for chunks that are currently checked out.
+*/
+static int memsys3Size(void *p){
+  Mem3Block *pBlock;
+  assert( p!=0 );
+  pBlock = (Mem3Block*)p;
+  assert( (pBlock[-1].u.hdr.size4x&1)!=0 );
+  return (pBlock[-1].u.hdr.size4x&~3)*2 - 4;
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int memsys3Roundup(int n){
+  if( n<=12 ){
+    return 12;
+  }else{
+    return ((n+11)&~7) - 4;
+  }
+}
+
+/*
+** Allocate nBytes of memory.
+*/
+static void *memsys3Malloc(int nBytes){
+  sqlite3_int64 *p;
+  assert( nBytes>0 );          /* malloc.c filters out 0 byte requests */
+  memsys3Enter();
+  p = memsys3MallocUnsafe(nBytes);
+  memsys3Leave();
+  return (void*)p;
+}
+
+/*
+** Free memory.
+*/
+static void memsys3Free(void *pPrior){
+  assert( pPrior );
+  memsys3Enter();
+  memsys3FreeUnsafe(pPrior);
+  memsys3Leave();
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+static void *memsys3Realloc(void *pPrior, int nBytes){
+  int nOld;
+  void *p;
+  if( pPrior==0 ){
+    return sqlite3_malloc(nBytes);
+  }
+  if( nBytes<=0 ){
+    sqlite3_free(pPrior);
+    return 0;
+  }
+  nOld = memsys3Size(pPrior);
+  if( nBytes<=nOld && nBytes>=nOld-128 ){
+    return pPrior;
+  }
+  memsys3Enter();
+  p = memsys3MallocUnsafe(nBytes);
+  if( p ){
+    if( nOld<nBytes ){
+      memcpy(p, pPrior, nOld);
+    }else{
+      memcpy(p, pPrior, nBytes);
+    }
+    memsys3FreeUnsafe(pPrior);
+  }
+  memsys3Leave();
+  return p;
+}
+
+/*
+** Initialize this module.
+*/
+static int memsys3Init(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  if( !sqlite3GlobalConfig.pHeap ){
+    return SQLITE_ERROR;
+  }
+
+  /* Store a pointer to the memory block in global structure mem3. */
+  assert( sizeof(Mem3Block)==8 );
+  mem3.aPool = (Mem3Block *)sqlite3GlobalConfig.pHeap;
+  mem3.nPool = (sqlite3GlobalConfig.nHeap / sizeof(Mem3Block)) - 2;
+
+  /* Initialize the key block. */
+  mem3.szKeyBlk = mem3.nPool;
+  mem3.mnKeyBlk = mem3.szKeyBlk;
+  mem3.iKeyBlk = 1;
+  mem3.aPool[0].u.hdr.size4x = (mem3.szKeyBlk<<2) + 2;
+  mem3.aPool[mem3.nPool].u.hdr.prevSize = mem3.nPool;
+  mem3.aPool[mem3.nPool].u.hdr.size4x = 1;
+
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize this module.
+*/
+static void memsys3Shutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  mem3.mutex = 0;
+  return;
+}
+
+
+
+/*
+** Open the file indicated and write a log of all unfreed memory
+** allocations into that log.
+*/
+SQLITE_PRIVATE void sqlite3Memsys3Dump(const char *zFilename){
+#ifdef SQLITE_DEBUG
+  FILE *out;
+  u32 i, j;
+  u32 size;
+  if( zFilename==0 || zFilename[0]==0 ){
+    out = stdout;
+  }else{
+    out = fopen(zFilename, "w");
+    if( out==0 ){
+      fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                      zFilename);
+      return;
+    }
+  }
+  memsys3Enter();
+  fprintf(out, "CHUNKS:\n");
+  for(i=1; i<=mem3.nPool; i+=size/4){
+    size = mem3.aPool[i-1].u.hdr.size4x;
+    if( size/4<=1 ){
+      fprintf(out, "%p size error\n", &mem3.aPool[i]);
+      assert( 0 );
+      break;
+    }
+    if( (size&1)==0 && mem3.aPool[i+size/4-1].u.hdr.prevSize!=size/4 ){
+      fprintf(out, "%p tail size does not match\n", &mem3.aPool[i]);
+      assert( 0 );
+      break;
+    }
+    if( ((mem3.aPool[i+size/4-1].u.hdr.size4x&2)>>1)!=(size&1) ){
+      fprintf(out, "%p tail checkout bit is incorrect\n", &mem3.aPool[i]);
+      assert( 0 );
+      break;
+    }
+    if( size&1 ){
+      fprintf(out, "%p %6d bytes checked out\n", &mem3.aPool[i], (size/4)*8-8);
+    }else{
+      fprintf(out, "%p %6d bytes free%s\n", &mem3.aPool[i], (size/4)*8-8,
+                  i==mem3.iKeyBlk ? " **key**" : "");
+    }
+  }
+  for(i=0; i<MX_SMALL-1; i++){
+    if( mem3.aiSmall[i]==0 ) continue;
+    fprintf(out, "small(%2d):", i);
+    for(j = mem3.aiSmall[i]; j>0; j=mem3.aPool[j].u.list.next){
+      fprintf(out, " %p(%d)", &mem3.aPool[j],
+              (mem3.aPool[j-1].u.hdr.size4x/4)*8-8);
+    }
+    fprintf(out, "\n");
+  }
+  for(i=0; i<N_HASH; i++){
+    if( mem3.aiHash[i]==0 ) continue;
+    fprintf(out, "hash(%2d):", i);
+    for(j = mem3.aiHash[i]; j>0; j=mem3.aPool[j].u.list.next){
+      fprintf(out, " %p(%d)", &mem3.aPool[j],
+              (mem3.aPool[j-1].u.hdr.size4x/4)*8-8);
+    }
+    fprintf(out, "\n");
+  }
+  fprintf(out, "key=%d\n", mem3.iKeyBlk);
+  fprintf(out, "nowUsed=%d\n", mem3.nPool*8 - mem3.szKeyBlk*8);
+  fprintf(out, "mxUsed=%d\n", mem3.nPool*8 - mem3.mnKeyBlk*8);
+  sqlite3_mutex_leave(mem3.mutex);
+  if( out==stdout ){
+    fflush(stdout);
+  }else{
+    fclose(out);
+  }
+#else
+  UNUSED_PARAMETER(zFilename);
+#endif
+}
+
+/*
+** This routine is the only routine in this file with external
+** linkage.
+**
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file. The
+** arguments specify the block of memory to manage.
+**
+** This routine is only called by sqlite3_config(), and therefore
+** is not required to be threadsafe (it is not).
+*/
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys3(void){
+  static const sqlite3_mem_methods mempoolMethods = {
+     memsys3Malloc,
+     memsys3Free,
+     memsys3Realloc,
+     memsys3Size,
+     memsys3Roundup,
+     memsys3Init,
+     memsys3Shutdown,
+     0
+  };
+  return &mempoolMethods;
+}
+
+#endif /* SQLITE_ENABLE_MEMSYS3 */
+
+/************** End of mem3.c ************************************************/
+/************** Begin file mem5.c ********************************************/
+/*
+** 2007 October 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement a memory
+** allocation subsystem for use by SQLite.
+**
+** This version of the memory allocation subsystem omits all
+** use of malloc(). The application gives SQLite a block of memory
+** before calling sqlite3_initialize() from which allocations
+** are made and returned by the xMalloc() and xRealloc()
+** implementations. Once sqlite3_initialize() has been called,
+** the amount of memory available to SQLite is fixed and cannot
+** be changed.
+**
+** This version of the memory allocation subsystem is included
+** in the build only if SQLITE_ENABLE_MEMSYS5 is defined.
+**
+** This memory allocator uses the following algorithm:
+**
+**   1.  All memory allocation sizes are rounded up to a power of 2.
+**
+**   2.  If two adjacent free blocks are the halves of a larger block,
+**       then the two blocks are coalesced into the single larger block.
+**
+**   3.  New memory is allocated from the first available free block.
+**
+** This algorithm is described in: J. M. Robson. "Bounds for Some Functions
+** Concerning Dynamic Storage Allocation". Journal of the Association for
+** Computing Machinery, Volume 21, Number 8, July 1974, pages 491-499.
+**
+** Let n be the size of the largest allocation divided by the minimum
+** allocation size (after rounding all sizes up to a power of 2.)  Let M
+** be the maximum amount of memory ever outstanding at one time.  Let
+** N be the total amount of memory available for allocation.  Robson
+** proved that this memory allocator will never breakdown due to
+** fragmentation as long as the following constraint holds:
+**
+**      N >=  M*(1 + log2(n)/2) - n + 1
+**
+** The sqlite3_status() logic tracks the maximum values of n and M so
+** that an application can, at any time, verify this constraint.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** This version of the memory allocator is used only when
+** SQLITE_ENABLE_MEMSYS5 is defined.
+*/
+#ifdef SQLITE_ENABLE_MEMSYS5
+
+/*
+** A minimum allocation is an instance of the following structure.
+** Larger allocations are an array of these structures where the
+** size of the array is a power of 2.
+**
+** The size of this object must be a power of two.  That fact is
+** verified in memsys5Init().
+*/
+typedef struct Mem5Link Mem5Link;
+struct Mem5Link {
+  int next;       /* Index of next free chunk */
+  int prev;       /* Index of previous free chunk */
+};
+
+/*
+** Maximum size of any allocation is ((1<<LOGMAX)*mem5.szAtom). Since
+** mem5.szAtom is always at least 8 and 32-bit integers are used,
+** it is not actually possible to reach this limit.
+*/
+#define LOGMAX 30
+
+/*
+** Masks used for mem5.aCtrl[] elements.
+*/
+#define CTRL_LOGSIZE  0x1f    /* Log2 Size of this block */
+#define CTRL_FREE     0x20    /* True if not checked out */
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem5".  This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static SQLITE_WSD struct Mem5Global {
+  /*
+  ** Memory available for allocation
+  */
+  int szAtom;      /* Smallest possible allocation in bytes */
+  int nBlock;      /* Number of szAtom sized blocks in zPool */
+  u8 *zPool;       /* Memory available to be allocated */
+
+  /*
+  ** Mutex to control access to the memory allocation subsystem.
+  */
+  sqlite3_mutex *mutex;
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /*
+  ** Performance statistics
+  */
+  u64 nAlloc;         /* Total number of calls to malloc */
+  u64 totalAlloc;     /* Total of all malloc calls - includes internal frag */
+  u64 totalExcess;    /* Total internal fragmentation */
+  u32 currentOut;     /* Current checkout, including internal fragmentation */
+  u32 currentCount;   /* Current number of distinct checkouts */
+  u32 maxOut;         /* Maximum instantaneous currentOut */
+  u32 maxCount;       /* Maximum instantaneous currentCount */
+  u32 maxRequest;     /* Largest allocation (exclusive of internal frag) */
+#endif
+
+  /*
+  ** Lists of free blocks.  aiFreelist[0] is a list of free blocks of
+  ** size mem5.szAtom.  aiFreelist[1] holds blocks of size szAtom*2.
+  ** aiFreelist[2] holds free blocks of size szAtom*4.  And so forth.
+  */
+  int aiFreelist[LOGMAX+1];
+
+  /*
+  ** Space for tracking which blocks are checked out and the size
+  ** of each block.  One byte per block.
+  */
+  u8 *aCtrl;
+
+} mem5;
+
+/*
+** Access the static variable through a macro for SQLITE_OMIT_WSD.
+*/
+#define mem5 GLOBAL(struct Mem5Global, mem5)
+
+/*
+** Assuming mem5.zPool is divided up into an array of Mem5Link
+** structures, return a pointer to the idx-th such link.
+*/
+#define MEM5LINK(idx) ((Mem5Link *)(&mem5.zPool[(idx)*mem5.szAtom]))
+
+/*
+** Unlink the chunk at mem5.aPool[i] from list it is currently
+** on.  It should be found on mem5.aiFreelist[iLogsize].
+*/
+static void memsys5Unlink(int i, int iLogsize){
+  int next, prev;
+  assert( i>=0 && i<mem5.nBlock );
+  assert( iLogsize>=0 && iLogsize<=LOGMAX );
+  assert( (mem5.aCtrl[i] & CTRL_LOGSIZE)==iLogsize );
+
+  next = MEM5LINK(i)->next;
+  prev = MEM5LINK(i)->prev;
+  if( prev<0 ){
+    mem5.aiFreelist[iLogsize] = next;
+  }else{
+    MEM5LINK(prev)->next = next;
+  }
+  if( next>=0 ){
+    MEM5LINK(next)->prev = prev;
+  }
+}
+
+/*
+** Link the chunk at mem5.aPool[i] so that is on the iLogsize
+** free list.
+*/
+static void memsys5Link(int i, int iLogsize){
+  int x;
+  assert( sqlite3_mutex_held(mem5.mutex) );
+  assert( i>=0 && i<mem5.nBlock );
+  assert( iLogsize>=0 && iLogsize<=LOGMAX );
+  assert( (mem5.aCtrl[i] & CTRL_LOGSIZE)==iLogsize );
+
+  x = MEM5LINK(i)->next = mem5.aiFreelist[iLogsize];
+  MEM5LINK(i)->prev = -1;
+  if( x>=0 ){
+    assert( x<mem5.nBlock );
+    MEM5LINK(x)->prev = i;
+  }
+  mem5.aiFreelist[iLogsize] = i;
+}
+
+/*
+** Obtain or release the mutex needed to access global data structures.
+*/
+static void memsys5Enter(void){
+  sqlite3_mutex_enter(mem5.mutex);
+}
+static void memsys5Leave(void){
+  sqlite3_mutex_leave(mem5.mutex);
+}
+
+/*
+** Return the size of an outstanding allocation, in bytes.
+** This only works for chunks that are currently checked out.
+*/
+static int memsys5Size(void *p){
+  int iSize, i;
+  assert( p!=0 );
+  i = (int)(((u8 *)p-mem5.zPool)/mem5.szAtom);
+  assert( i>=0 && i<mem5.nBlock );
+  iSize = mem5.szAtom * (1 << (mem5.aCtrl[i]&CTRL_LOGSIZE));
+  return iSize;
+}
+
+/*
+** Return a block of memory of at least nBytes in size.
+** Return NULL if unable.  Return NULL if nBytes==0.
+**
+** The caller guarantees that nByte is positive.
+**
+** The caller has obtained a mutex prior to invoking this
+** routine so there is never any chance that two or more
+** threads can be in this routine at the same time.
+*/
+static void *memsys5MallocUnsafe(int nByte){
+  int i;           /* Index of a mem5.aPool[] slot */
+  int iBin;        /* Index into mem5.aiFreelist[] */
+  int iFullSz;     /* Size of allocation rounded up to power of 2 */
+  int iLogsize;    /* Log2 of iFullSz/POW2_MIN */
+
+  /* nByte must be a positive */
+  assert( nByte>0 );
+
+  /* No more than 1GiB per allocation */
+  if( nByte > 0x40000000 ) return 0;
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /* Keep track of the maximum allocation request.  Even unfulfilled
+  ** requests are counted */
+  if( (u32)nByte>mem5.maxRequest ){
+    mem5.maxRequest = nByte;
+  }
+#endif
+
+
+  /* Round nByte up to the next valid power of two */
+  for(iFullSz=mem5.szAtom,iLogsize=0; iFullSz<nByte; iFullSz*=2,iLogsize++){}
+
+  /* Make sure mem5.aiFreelist[iLogsize] contains at least one free
+  ** block.  If not, then split a block of the next larger power of
+  ** two in order to create a new free block of size iLogsize.
+  */
+  for(iBin=iLogsize; iBin<=LOGMAX && mem5.aiFreelist[iBin]<0; iBin++){}
+  if( iBin>LOGMAX ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes", nByte);
+    return 0;
+  }
+  i = mem5.aiFreelist[iBin];
+  memsys5Unlink(i, iBin);
+  while( iBin>iLogsize ){
+    int newSize;
+
+    iBin--;
+    newSize = 1 << iBin;
+    mem5.aCtrl[i+newSize] = CTRL_FREE | iBin;
+    memsys5Link(i+newSize, iBin);
+  }
+  mem5.aCtrl[i] = iLogsize;
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /* Update allocator performance statistics. */
+  mem5.nAlloc++;
+  mem5.totalAlloc += iFullSz;
+  mem5.totalExcess += iFullSz - nByte;
+  mem5.currentCount++;
+  mem5.currentOut += iFullSz;
+  if( mem5.maxCount<mem5.currentCount ) mem5.maxCount = mem5.currentCount;
+  if( mem5.maxOut<mem5.currentOut ) mem5.maxOut = mem5.currentOut;
+#endif
+
+#ifdef SQLITE_DEBUG
+  /* Make sure the allocated memory does not assume that it is set to zero
+  ** or retains a value from a previous allocation */
+  memset(&mem5.zPool[i*mem5.szAtom], 0xAA, iFullSz);
+#endif
+
+  /* Return a pointer to the allocated memory. */
+  return (void*)&mem5.zPool[i*mem5.szAtom];
+}
+
+/*
+** Free an outstanding memory allocation.
+*/
+static void memsys5FreeUnsafe(void *pOld){
+  u32 size, iLogsize;
+  int iBlock;
+
+  /* Set iBlock to the index of the block pointed to by pOld in
+  ** the array of mem5.szAtom byte blocks pointed to by mem5.zPool.
+  */
+  iBlock = (int)(((u8 *)pOld-mem5.zPool)/mem5.szAtom);
+
+  /* Check that the pointer pOld points to a valid, non-free block. */
+  assert( iBlock>=0 && iBlock<mem5.nBlock );
+  assert( ((u8 *)pOld-mem5.zPool)%mem5.szAtom==0 );
+  assert( (mem5.aCtrl[iBlock] & CTRL_FREE)==0 );
+
+  iLogsize = mem5.aCtrl[iBlock] & CTRL_LOGSIZE;
+  size = 1<<iLogsize;
+  assert( iBlock+size-1<(u32)mem5.nBlock );
+
+  mem5.aCtrl[iBlock] |= CTRL_FREE;
+  mem5.aCtrl[iBlock+size-1] |= CTRL_FREE;
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  assert( mem5.currentCount>0 );
+  assert( mem5.currentOut>=(size*mem5.szAtom) );
+  mem5.currentCount--;
+  mem5.currentOut -= size*mem5.szAtom;
+  assert( mem5.currentOut>0 || mem5.currentCount==0 );
+  assert( mem5.currentCount>0 || mem5.currentOut==0 );
+#endif
+
+  mem5.aCtrl[iBlock] = CTRL_FREE | iLogsize;
+  while( ALWAYS(iLogsize<LOGMAX) ){
+    int iBuddy;
+    if( (iBlock>>iLogsize) & 1 ){
+      iBuddy = iBlock - size;
+      assert( iBuddy>=0 );
+    }else{
+      iBuddy = iBlock + size;
+      if( iBuddy>=mem5.nBlock ) break;
+    }
+    if( mem5.aCtrl[iBuddy]!=(CTRL_FREE | iLogsize) ) break;
+    memsys5Unlink(iBuddy, iLogsize);
+    iLogsize++;
+    if( iBuddy<iBlock ){
+      mem5.aCtrl[iBuddy] = CTRL_FREE | iLogsize;
+      mem5.aCtrl[iBlock] = 0;
+      iBlock = iBuddy;
+    }else{
+      mem5.aCtrl[iBlock] = CTRL_FREE | iLogsize;
+      mem5.aCtrl[iBuddy] = 0;
+    }
+    size *= 2;
+  }
+
+#ifdef SQLITE_DEBUG
+  /* Overwrite freed memory with the 0x55 bit pattern to verify that it is
+  ** not used after being freed */
+  memset(&mem5.zPool[iBlock*mem5.szAtom], 0x55, size);
+#endif
+
+  memsys5Link(iBlock, iLogsize);
+}
+
+/*
+** Allocate nBytes of memory.
+*/
+static void *memsys5Malloc(int nBytes){
+  sqlite3_int64 *p = 0;
+  if( nBytes>0 ){
+    memsys5Enter();
+    p = memsys5MallocUnsafe(nBytes);
+    memsys5Leave();
+  }
+  return (void*)p;
+}
+
+/*
+** Free memory.
+**
+** The outer layer memory allocator prevents this routine from
+** being called with pPrior==0.
+*/
+static void memsys5Free(void *pPrior){
+  assert( pPrior!=0 );
+  memsys5Enter();
+  memsys5FreeUnsafe(pPrior);
+  memsys5Leave();
+}
+
+/*
+** Change the size of an existing memory allocation.
+**
+** The outer layer memory allocator prevents this routine from
+** being called with pPrior==0.
+**
+** nBytes is always a value obtained from a prior call to
+** memsys5Round().  Hence nBytes is always a non-negative power
+** of two.  If nBytes==0 that means that an oversize allocation
+** (an allocation larger than 0x40000000) was requested and this
+** routine should return 0 without freeing pPrior.
+*/
+static void *memsys5Realloc(void *pPrior, int nBytes){
+  int nOld;
+  void *p;
+  assert( pPrior!=0 );
+  assert( (nBytes&(nBytes-1))==0 );  /* EV: R-46199-30249 */
+  assert( nBytes>=0 );
+  if( nBytes==0 ){
+    return 0;
+  }
+  nOld = memsys5Size(pPrior);
+  if( nBytes<=nOld ){
+    return pPrior;
+  }
+  p = memsys5Malloc(nBytes);
+  if( p ){
+    memcpy(p, pPrior, nOld);
+    memsys5Free(pPrior);
+  }
+  return p;
+}
+
+/*
+** Round up a request size to the next valid allocation size.  If
+** the allocation is too large to be handled by this allocation system,
+** return 0.
+**
+** All allocations must be a power of two and must be expressed by a
+** 32-bit signed integer.  Hence the largest allocation is 0x40000000
+** or 1073741824 bytes.
+*/
+static int memsys5Roundup(int n){
+  int iFullSz;
+  if( n<=mem5.szAtom*2 ){
+    if( n<=mem5.szAtom ) return mem5.szAtom;
+    return mem5.szAtom*2;
+  }
+  if( n>0x10000000 ){
+    if( n>0x40000000 ) return 0;
+    if( n>0x20000000 ) return 0x40000000;
+    return 0x20000000;
+  }
+  for(iFullSz=mem5.szAtom*8; iFullSz<n; iFullSz *= 4);
+  if( (iFullSz/2)>=(i64)n ) return iFullSz/2;
+  return iFullSz;
+}
+
+/*
+** Return the ceiling of the logarithm base 2 of iValue.
+**
+** Examples:   memsys5Log(1) -> 0
+**             memsys5Log(2) -> 1
+**             memsys5Log(4) -> 2
+**             memsys5Log(5) -> 3
+**             memsys5Log(8) -> 3
+**             memsys5Log(9) -> 4
+*/
+static int memsys5Log(int iValue){
+  int iLog;
+  for(iLog=0; (iLog<(int)((sizeof(int)*8)-1)) && (1<<iLog)<iValue; iLog++);
+  return iLog;
+}
+
+/*
+** Initialize the memory allocator.
+**
+** This routine is not threadsafe.  The caller must be holding a mutex
+** to prevent multiple threads from entering at the same time.
+*/
+static int memsys5Init(void *NotUsed){
+  int ii;            /* Loop counter */
+  int nByte;         /* Number of bytes of memory available to this allocator */
+  u8 *zByte;         /* Memory usable by this allocator */
+  int nMinLog;       /* Log base 2 of minimum allocation size in bytes */
+  int iOffset;       /* An offset into mem5.aCtrl[] */
+
+  UNUSED_PARAMETER(NotUsed);
+
+  /* For the purposes of this routine, disable the mutex */
+  mem5.mutex = 0;
+
+  /* The size of a Mem5Link object must be a power of two.  Verify that
+  ** this is case.
+  */
+  assert( (sizeof(Mem5Link)&(sizeof(Mem5Link)-1))==0 );
+
+  nByte = sqlite3GlobalConfig.nHeap;
+  zByte = (u8*)sqlite3GlobalConfig.pHeap;
+  assert( zByte!=0 );  /* sqlite3_config() does not allow otherwise */
+
+  /* boundaries on sqlite3GlobalConfig.mnReq are enforced in sqlite3_config() */
+  nMinLog = memsys5Log(sqlite3GlobalConfig.mnReq);
+  mem5.szAtom = (1<<nMinLog);
+  while( (int)sizeof(Mem5Link)>mem5.szAtom ){
+    mem5.szAtom = mem5.szAtom << 1;
+  }
+
+  mem5.nBlock = (nByte / (mem5.szAtom+sizeof(u8)));
+  mem5.zPool = zByte;
+  mem5.aCtrl = (u8 *)&mem5.zPool[mem5.nBlock*mem5.szAtom];
+
+  for(ii=0; ii<=LOGMAX; ii++){
+    mem5.aiFreelist[ii] = -1;
+  }
+
+  iOffset = 0;
+  for(ii=LOGMAX; ii>=0; ii--){
+    int nAlloc = (1<<ii);
+    if( (iOffset+nAlloc)<=mem5.nBlock ){
+      mem5.aCtrl[iOffset] = ii | CTRL_FREE;
+      memsys5Link(iOffset, ii);
+      iOffset += nAlloc;
+    }
+    assert((iOffset+nAlloc)>mem5.nBlock);
+  }
+
+  /* If a mutex is required for normal operation, allocate one */
+  if( sqlite3GlobalConfig.bMemstat==0 ){
+    mem5.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize this module.
+*/
+static void memsys5Shutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  mem5.mutex = 0;
+  return;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Open the file indicated and write a log of all unfreed memory
+** allocations into that log.
+*/
+SQLITE_PRIVATE void sqlite3Memsys5Dump(const char *zFilename){
+  FILE *out;
+  int i, j, n;
+  int nMinLog;
+
+  if( zFilename==0 || zFilename[0]==0 ){
+    out = stdout;
+  }else{
+    out = fopen(zFilename, "w");
+    if( out==0 ){
+      fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+                      zFilename);
+      return;
+    }
+  }
+  memsys5Enter();
+  nMinLog = memsys5Log(mem5.szAtom);
+  for(i=0; i<=LOGMAX && i+nMinLog<32; i++){
+    for(n=0, j=mem5.aiFreelist[i]; j>=0; j = MEM5LINK(j)->next, n++){}
+    fprintf(out, "freelist items of size %d: %d\n", mem5.szAtom << i, n);
+  }
+  fprintf(out, "mem5.nAlloc       = %llu\n", mem5.nAlloc);
+  fprintf(out, "mem5.totalAlloc   = %llu\n", mem5.totalAlloc);
+  fprintf(out, "mem5.totalExcess  = %llu\n", mem5.totalExcess);
+  fprintf(out, "mem5.currentOut   = %u\n", mem5.currentOut);
+  fprintf(out, "mem5.currentCount = %u\n", mem5.currentCount);
+  fprintf(out, "mem5.maxOut       = %u\n", mem5.maxOut);
+  fprintf(out, "mem5.maxCount     = %u\n", mem5.maxCount);
+  fprintf(out, "mem5.maxRequest   = %u\n", mem5.maxRequest);
+  memsys5Leave();
+  if( out==stdout ){
+    fflush(stdout);
+  }else{
+    fclose(out);
+  }
+}
+#endif
+
+/*
+** This routine is the only routine in this file with external
+** linkage. It returns a pointer to a static sqlite3_mem_methods
+** struct populated with the memsys5 methods.
+*/
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetMemsys5(void){
+  static const sqlite3_mem_methods memsys5Methods = {
+     memsys5Malloc,
+     memsys5Free,
+     memsys5Realloc,
+     memsys5Size,
+     memsys5Roundup,
+     memsys5Init,
+     memsys5Shutdown,
+     0
+  };
+  return &memsys5Methods;
+}
+
+#endif /* SQLITE_ENABLE_MEMSYS5 */
+
+/************** End of mem5.c ************************************************/
+/************** Begin file mutex.c *******************************************/
+/*
+** 2007 August 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes.
+**
+** This file contains code that is common across all mutex implementations.
+*/
+/* #include "sqliteInt.h" */
+
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_MUTEX_OMIT)
+/*
+** For debugging purposes, record when the mutex subsystem is initialized
+** and uninitialized so that we can assert() if there is an attempt to
+** allocate a mutex while the system is uninitialized.
+*/
+static SQLITE_WSD int mutexIsInit = 0;
+#endif /* SQLITE_DEBUG && !defined(SQLITE_MUTEX_OMIT) */
+
+
+#ifndef SQLITE_MUTEX_OMIT
+
+#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
+/*
+** This block (enclosed by SQLITE_ENABLE_MULTITHREADED_CHECKS) contains
+** the implementation of a wrapper around the system default mutex
+** implementation (sqlite3DefaultMutex()).
+**
+** Most calls are passed directly through to the underlying default
+** mutex implementation. Except, if a mutex is configured by calling
+** sqlite3MutexWarnOnContention() on it, then if contention is ever
+** encountered within xMutexEnter() a warning is emitted via sqlite3_log().
+**
+** This type of mutex is used as the database handle mutex when testing
+** apps that usually use SQLITE_CONFIG_MULTITHREAD mode.
+*/
+
+/*
+** Type for all mutexes used when SQLITE_ENABLE_MULTITHREADED_CHECKS
+** is defined. Variable CheckMutex.mutex is a pointer to the real mutex
+** allocated by the system mutex implementation. Variable iType is usually set
+** to the type of mutex requested - SQLITE_MUTEX_RECURSIVE, SQLITE_MUTEX_FAST
+** or one of the static mutex identifiers. Or, if this is a recursive mutex
+** that has been configured using sqlite3MutexWarnOnContention(), it is
+** set to SQLITE_MUTEX_WARNONCONTENTION.
+*/
+typedef struct CheckMutex CheckMutex;
+struct CheckMutex {
+  int iType;
+  sqlite3_mutex *mutex;
+};
+
+#define SQLITE_MUTEX_WARNONCONTENTION  (-1)
+
+/*
+** Pointer to real mutex methods object used by the CheckMutex
+** implementation. Set by checkMutexInit().
+*/
+static SQLITE_WSD const sqlite3_mutex_methods *pGlobalMutexMethods;
+
+#ifdef SQLITE_DEBUG
+static int checkMutexHeld(sqlite3_mutex *p){
+  return pGlobalMutexMethods->xMutexHeld(((CheckMutex*)p)->mutex);
+}
+static int checkMutexNotheld(sqlite3_mutex *p){
+  return pGlobalMutexMethods->xMutexNotheld(((CheckMutex*)p)->mutex);
+}
+#endif
+
+/*
+** Initialize and deinitialize the mutex subsystem.
+*/
+static int checkMutexInit(void){
+  pGlobalMutexMethods = sqlite3DefaultMutex();
+  return SQLITE_OK;
+}
+static int checkMutexEnd(void){
+  pGlobalMutexMethods = 0;
+  return SQLITE_OK;
+}
+
+/*
+** Allocate a mutex.
+*/
+static sqlite3_mutex *checkMutexAlloc(int iType){
+  static CheckMutex staticMutexes[] = {
+    {2, 0}, {3, 0}, {4, 0}, {5, 0},
+    {6, 0}, {7, 0}, {8, 0}, {9, 0},
+    {10, 0}, {11, 0}, {12, 0}, {13, 0}
+  };
+  CheckMutex *p = 0;
+
+  assert( SQLITE_MUTEX_RECURSIVE==1 && SQLITE_MUTEX_FAST==0 );
+  if( iType<2 ){
+    p = sqlite3MallocZero(sizeof(CheckMutex));
+    if( p==0 ) return 0;
+    p->iType = iType;
+  }else{
+#ifdef SQLITE_ENABLE_API_ARMOR
+    if( iType-2>=ArraySize(staticMutexes) ){
+      (void)SQLITE_MISUSE_BKPT;
+      return 0;
+    }
+#endif
+    p = &staticMutexes[iType-2];
+  }
+
+  if( p->mutex==0 ){
+    p->mutex = pGlobalMutexMethods->xMutexAlloc(iType);
+    if( p->mutex==0 ){
+      if( iType<2 ){
+        sqlite3_free(p);
+      }
+      p = 0;
+    }
+  }
+
+  return (sqlite3_mutex*)p;
+}
+
+/*
+** Free a mutex.
+*/
+static void checkMutexFree(sqlite3_mutex *p){
+  assert( SQLITE_MUTEX_RECURSIVE<2 );
+  assert( SQLITE_MUTEX_FAST<2 );
+  assert( SQLITE_MUTEX_WARNONCONTENTION<2 );
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ((CheckMutex*)p)->iType<2 )
+#endif
+  {
+    CheckMutex *pCheck = (CheckMutex*)p;
+    pGlobalMutexMethods->xMutexFree(pCheck->mutex);
+    sqlite3_free(pCheck);
+  }
+#ifdef SQLITE_ENABLE_API_ARMOR
+  else{
+    (void)SQLITE_MISUSE_BKPT;
+  }
+#endif
+}
+
+/*
+** Enter the mutex.
+*/
+static void checkMutexEnter(sqlite3_mutex *p){
+  CheckMutex *pCheck = (CheckMutex*)p;
+  if( pCheck->iType==SQLITE_MUTEX_WARNONCONTENTION ){
+    if( SQLITE_OK==pGlobalMutexMethods->xMutexTry(pCheck->mutex) ){
+      return;
+    }
+    sqlite3_log(SQLITE_MISUSE,
+        "illegal multi-threaded access to database connection"
+    );
+  }
+  pGlobalMutexMethods->xMutexEnter(pCheck->mutex);
+}
+
+/*
+** Enter the mutex (do not block).
+*/
+static int checkMutexTry(sqlite3_mutex *p){
+  CheckMutex *pCheck = (CheckMutex*)p;
+  return pGlobalMutexMethods->xMutexTry(pCheck->mutex);
+}
+
+/*
+** Leave the mutex.
+*/
+static void checkMutexLeave(sqlite3_mutex *p){
+  CheckMutex *pCheck = (CheckMutex*)p;
+  pGlobalMutexMethods->xMutexLeave(pCheck->mutex);
+}
+
+sqlite3_mutex_methods const *multiThreadedCheckMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    checkMutexInit,
+    checkMutexEnd,
+    checkMutexAlloc,
+    checkMutexFree,
+    checkMutexEnter,
+    checkMutexTry,
+    checkMutexLeave,
+#ifdef SQLITE_DEBUG
+    checkMutexHeld,
+    checkMutexNotheld
+#else
+    0,
+    0
+#endif
+  };
+  return &sMutex;
+}
+
+/*
+** Mark the SQLITE_MUTEX_RECURSIVE mutex passed as the only argument as
+** one on which there should be no contention.
+*/
+SQLITE_PRIVATE void sqlite3MutexWarnOnContention(sqlite3_mutex *p){
+  if( sqlite3GlobalConfig.mutex.xMutexAlloc==checkMutexAlloc ){
+    CheckMutex *pCheck = (CheckMutex*)p;
+    assert( pCheck->iType==SQLITE_MUTEX_RECURSIVE );
+    pCheck->iType = SQLITE_MUTEX_WARNONCONTENTION;
+  }
+}
+#endif   /* ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS */
+
+/*
+** Initialize the mutex system.
+*/
+SQLITE_PRIVATE int sqlite3MutexInit(void){
+  int rc = SQLITE_OK;
+  if( !sqlite3GlobalConfig.mutex.xMutexAlloc ){
+    /* If the xMutexAlloc method has not been set, then the user did not
+    ** install a mutex implementation via sqlite3_config() prior to
+    ** sqlite3_initialize() being called. This block copies pointers to
+    ** the default implementation into the sqlite3GlobalConfig structure.
+    */
+    sqlite3_mutex_methods const *pFrom;
+    sqlite3_mutex_methods *pTo = &sqlite3GlobalConfig.mutex;
+
+    if( sqlite3GlobalConfig.bCoreMutex ){
+#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
+      pFrom = multiThreadedCheckMutex();
+#else
+      pFrom = sqlite3DefaultMutex();
+#endif
+    }else{
+      pFrom = sqlite3NoopMutex();
+    }
+    pTo->xMutexInit = pFrom->xMutexInit;
+    pTo->xMutexEnd = pFrom->xMutexEnd;
+    pTo->xMutexFree = pFrom->xMutexFree;
+    pTo->xMutexEnter = pFrom->xMutexEnter;
+    pTo->xMutexTry = pFrom->xMutexTry;
+    pTo->xMutexLeave = pFrom->xMutexLeave;
+    pTo->xMutexHeld = pFrom->xMutexHeld;
+    pTo->xMutexNotheld = pFrom->xMutexNotheld;
+    sqlite3MemoryBarrier();
+    pTo->xMutexAlloc = pFrom->xMutexAlloc;
+  }
+  assert( sqlite3GlobalConfig.mutex.xMutexInit );
+  rc = sqlite3GlobalConfig.mutex.xMutexInit();
+
+#ifdef SQLITE_DEBUG
+  GLOBAL(int, mutexIsInit) = 1;
+#endif
+
+  sqlite3MemoryBarrier();
+  return rc;
+}
+
+/*
+** Shutdown the mutex system. This call frees resources allocated by
+** sqlite3MutexInit().
+*/
+SQLITE_PRIVATE int sqlite3MutexEnd(void){
+  int rc = SQLITE_OK;
+  if( sqlite3GlobalConfig.mutex.xMutexEnd ){
+    rc = sqlite3GlobalConfig.mutex.xMutexEnd();
+  }
+
+#ifdef SQLITE_DEBUG
+  GLOBAL(int, mutexIsInit) = 0;
+#endif
+
+  return rc;
+}
+
+/*
+** Retrieve a pointer to a static mutex or allocate a new dynamic one.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int id){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( id<=SQLITE_MUTEX_RECURSIVE && sqlite3_initialize() ) return 0;
+  if( id>SQLITE_MUTEX_RECURSIVE && sqlite3MutexInit() ) return 0;
+#endif
+  assert( sqlite3GlobalConfig.mutex.xMutexAlloc );
+  return sqlite3GlobalConfig.mutex.xMutexAlloc(id);
+}
+
+SQLITE_PRIVATE sqlite3_mutex *sqlite3MutexAlloc(int id){
+  if( !sqlite3GlobalConfig.bCoreMutex ){
+    return 0;
+  }
+  assert( GLOBAL(int, mutexIsInit) );
+  assert( sqlite3GlobalConfig.mutex.xMutexAlloc );
+  return sqlite3GlobalConfig.mutex.xMutexAlloc(id);
+}
+
+/*
+** Free a dynamic mutex.
+*/
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex *p){
+  if( p ){
+    assert( sqlite3GlobalConfig.mutex.xMutexFree );
+    sqlite3GlobalConfig.mutex.xMutexFree(p);
+  }
+}
+
+/*
+** Obtain the mutex p. If some other thread already has the mutex, block
+** until it can be obtained.
+*/
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex *p){
+  if( p ){
+    assert( sqlite3GlobalConfig.mutex.xMutexEnter );
+    sqlite3GlobalConfig.mutex.xMutexEnter(p);
+  }
+}
+
+/*
+** Obtain the mutex p. If successful, return SQLITE_OK. Otherwise, if another
+** thread holds the mutex and it cannot be obtained, return SQLITE_BUSY.
+*/
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex *p){
+  int rc = SQLITE_OK;
+  if( p ){
+    assert( sqlite3GlobalConfig.mutex.xMutexTry );
+    return sqlite3GlobalConfig.mutex.xMutexTry(p);
+  }
+  return rc;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was previously
+** entered by the same thread.  The behavior is undefined if the mutex
+** is not currently entered. If a NULL pointer is passed as an argument
+** this function is a no-op.
+*/
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex *p){
+  if( p ){
+    assert( sqlite3GlobalConfig.mutex.xMutexLeave );
+    sqlite3GlobalConfig.mutex.xMutexLeave(p);
+  }
+}
+
+#ifndef NDEBUG
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use inside assert() statements.
+**
+** Because these routines raise false-positive alerts in TSAN, disable
+** them (make them always return 1) when compiling with TSAN.
+*/
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex *p){
+# if defined(__has_feature)
+#   if __has_feature(thread_sanitizer)
+      p = 0;
+#   endif
+# endif
+  assert( p==0 || sqlite3GlobalConfig.mutex.xMutexHeld );
+  return p==0 || sqlite3GlobalConfig.mutex.xMutexHeld(p);
+}
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex *p){
+# if defined(__has_feature)
+#   if __has_feature(thread_sanitizer)
+      p = 0;
+#   endif
+# endif
+  assert( p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld );
+  return p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld(p);
+}
+#endif /* NDEBUG */
+
+#endif /* !defined(SQLITE_MUTEX_OMIT) */
+
+/************** End of mutex.c ***********************************************/
+/************** Begin file mutex_noop.c **************************************/
+/*
+** 2008 October 07
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes.
+**
+** This implementation in this file does not provide any mutual
+** exclusion and is thus suitable for use only in applications
+** that use SQLite in a single thread.  The routines defined
+** here are place-holders.  Applications can substitute working
+** mutex routines at start-time using the
+**
+**     sqlite3_config(SQLITE_CONFIG_MUTEX,...)
+**
+** interface.
+**
+** If compiled with SQLITE_DEBUG, then additional logic is inserted
+** that does error checking on mutexes to make sure they are being
+** called correctly.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_MUTEX_OMIT
+
+#ifndef SQLITE_DEBUG
+/*
+** Stub routines for all mutex methods.
+**
+** This routines provide no mutual exclusion or error checking.
+*/
+static int noopMutexInit(void){ return SQLITE_OK; }
+static int noopMutexEnd(void){ return SQLITE_OK; }
+static sqlite3_mutex *noopMutexAlloc(int id){
+  UNUSED_PARAMETER(id);
+  return (sqlite3_mutex*)8;
+}
+static void noopMutexFree(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
+static void noopMutexEnter(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
+static int noopMutexTry(sqlite3_mutex *p){
+  UNUSED_PARAMETER(p);
+  return SQLITE_OK;
+}
+static void noopMutexLeave(sqlite3_mutex *p){ UNUSED_PARAMETER(p); return; }
+
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3NoopMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    noopMutexInit,
+    noopMutexEnd,
+    noopMutexAlloc,
+    noopMutexFree,
+    noopMutexEnter,
+    noopMutexTry,
+    noopMutexLeave,
+
+    0,
+    0,
+  };
+
+  return &sMutex;
+}
+#endif /* !SQLITE_DEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+** In this implementation, error checking is provided for testing
+** and debugging purposes.  The mutexes still do not provide any
+** mutual exclusion.
+*/
+
+/*
+** The mutex object
+*/
+typedef struct sqlite3_debug_mutex {
+  int id;     /* The mutex type */
+  int cnt;    /* Number of entries without a matching leave */
+} sqlite3_debug_mutex;
+
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use inside assert() statements.
+*/
+static int debugMutexHeld(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  return p==0 || p->cnt>0;
+}
+static int debugMutexNotheld(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  return p==0 || p->cnt==0;
+}
+
+/*
+** Initialize and deinitialize the mutex subsystem.
+*/
+static int debugMutexInit(void){ return SQLITE_OK; }
+static int debugMutexEnd(void){ return SQLITE_OK; }
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated.
+*/
+static sqlite3_mutex *debugMutexAlloc(int id){
+  static sqlite3_debug_mutex aStatic[SQLITE_MUTEX_STATIC_VFS3 - 1];
+  sqlite3_debug_mutex *pNew = 0;
+  switch( id ){
+    case SQLITE_MUTEX_FAST:
+    case SQLITE_MUTEX_RECURSIVE: {
+      pNew = sqlite3Malloc(sizeof(*pNew));
+      if( pNew ){
+        pNew->id = id;
+        pNew->cnt = 0;
+      }
+      break;
+    }
+    default: {
+#ifdef SQLITE_ENABLE_API_ARMOR
+      if( id-2<0 || id-2>=ArraySize(aStatic) ){
+        (void)SQLITE_MISUSE_BKPT;
+        return 0;
+      }
+#endif
+      pNew = &aStatic[id-2];
+      pNew->id = id;
+      break;
+    }
+  }
+  return (sqlite3_mutex*)pNew;
+}
+
+/*
+** This routine deallocates a previously allocated mutex.
+*/
+static void debugMutexFree(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( p->cnt==0 );
+  if( p->id==SQLITE_MUTEX_RECURSIVE || p->id==SQLITE_MUTEX_FAST ){
+    sqlite3_free(p);
+  }else{
+#ifdef SQLITE_ENABLE_API_ARMOR
+    (void)SQLITE_MISUSE_BKPT;
+#endif
+  }
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+static void debugMutexEnter(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(pX) );
+  p->cnt++;
+}
+static int debugMutexTry(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(pX) );
+  p->cnt++;
+  return SQLITE_OK;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+static void debugMutexLeave(sqlite3_mutex *pX){
+  sqlite3_debug_mutex *p = (sqlite3_debug_mutex*)pX;
+  assert( debugMutexHeld(pX) );
+  p->cnt--;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || debugMutexNotheld(pX) );
+}
+
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3NoopMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    debugMutexInit,
+    debugMutexEnd,
+    debugMutexAlloc,
+    debugMutexFree,
+    debugMutexEnter,
+    debugMutexTry,
+    debugMutexLeave,
+
+    debugMutexHeld,
+    debugMutexNotheld
+  };
+
+  return &sMutex;
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** If compiled with SQLITE_MUTEX_NOOP, then the no-op mutex implementation
+** is used regardless of the run-time threadsafety setting.
+*/
+#ifdef SQLITE_MUTEX_NOOP
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
+  return sqlite3NoopMutex();
+}
+#endif /* defined(SQLITE_MUTEX_NOOP) */
+#endif /* !defined(SQLITE_MUTEX_OMIT) */
+
+/************** End of mutex_noop.c ******************************************/
+/************** Begin file mutex_unix.c **************************************/
+/*
+** 2007 August 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes for pthreads
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** The code in this file is only used if we are compiling threadsafe
+** under unix with pthreads.
+**
+** Note that this implementation requires a version of pthreads that
+** supports recursive mutexes.
+*/
+#ifdef SQLITE_MUTEX_PTHREADS
+
+#include <pthread.h>
+
+/*
+** The sqlite3_mutex.id, sqlite3_mutex.nRef, and sqlite3_mutex.owner fields
+** are necessary under two conditions:  (1) Debug builds and (2) using
+** home-grown mutexes.  Encapsulate these conditions into a single #define.
+*/
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HOMEGROWN_RECURSIVE_MUTEX)
+# define SQLITE_MUTEX_NREF 1
+#else
+# define SQLITE_MUTEX_NREF 0
+#endif
+
+/*
+** Each recursive mutex is an instance of the following structure.
+*/
+struct sqlite3_mutex {
+  pthread_mutex_t mutex;     /* Mutex controlling the lock */
+#if SQLITE_MUTEX_NREF || defined(SQLITE_ENABLE_API_ARMOR)
+  int id;                    /* Mutex type */
+#endif
+#if SQLITE_MUTEX_NREF
+  volatile int nRef;         /* Number of entrances */
+  volatile pthread_t owner;  /* Thread that is within this mutex */
+  int trace;                 /* True to trace changes */
+#endif
+};
+#if SQLITE_MUTEX_NREF
+# define SQLITE3_MUTEX_INITIALIZER(id) \
+     {PTHREAD_MUTEX_INITIALIZER,id,0,(pthread_t)0,0}
+#elif defined(SQLITE_ENABLE_API_ARMOR)
+# define SQLITE3_MUTEX_INITIALIZER(id) { PTHREAD_MUTEX_INITIALIZER, id }
+#else
+#define SQLITE3_MUTEX_INITIALIZER(id) { PTHREAD_MUTEX_INITIALIZER }
+#endif
+
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use only inside assert() statements.  On some platforms,
+** there might be race conditions that can cause these routines to
+** deliver incorrect results.  In particular, if pthread_equal() is
+** not an atomic operation, then these routines might delivery
+** incorrect results.  On most platforms, pthread_equal() is a
+** comparison of two integers and is therefore atomic.  But we are
+** told that HPUX is not such a platform.  If so, then these routines
+** will not always work correctly on HPUX.
+**
+** On those platforms where pthread_equal() is not atomic, SQLite
+** should be compiled without -DSQLITE_DEBUG and with -DNDEBUG to
+** make sure no assert() statements are evaluated and hence these
+** routines are never called.
+*/
+#if !defined(NDEBUG) || defined(SQLITE_DEBUG)
+static int pthreadMutexHeld(sqlite3_mutex *p){
+  return (p->nRef!=0 && pthread_equal(p->owner, pthread_self()));
+}
+static int pthreadMutexNotheld(sqlite3_mutex *p){
+  return p->nRef==0 || pthread_equal(p->owner, pthread_self())==0;
+}
+#endif
+
+/*
+** Try to provide a memory barrier operation, needed for initialization
+** and also for the implementation of xShmBarrier in the VFS in cases
+** where SQLite is compiled without mutexes.
+*/
+SQLITE_PRIVATE void sqlite3MemoryBarrier(void){
+#if defined(SQLITE_MEMORY_BARRIER)
+  SQLITE_MEMORY_BARRIER;
+#elif defined(__GNUC__) && GCC_VERSION>=4001000
+  __sync_synchronize();
+#endif
+}
+
+/*
+** Initialize and deinitialize the mutex subsystem.
+*/
+static int pthreadMutexInit(void){ return SQLITE_OK; }
+static int pthreadMutexEnd(void){ return SQLITE_OK; }
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated.  SQLite
+** will unwind its stack and return an error.  The argument
+** to sqlite3_mutex_alloc() is one of these integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MAIN
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_OPEN
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
+** <li>  SQLITE_MUTEX_STATIC_APP1
+** <li>  SQLITE_MUTEX_STATIC_APP2
+** <li>  SQLITE_MUTEX_STATIC_APP3
+** <li>  SQLITE_MUTEX_STATIC_VFS1
+** <li>  SQLITE_MUTEX_STATIC_VFS2
+** <li>  SQLITE_MUTEX_STATIC_VFS3
+** </ul>
+**
+** The first two constants cause sqlite3_mutex_alloc() to create
+** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  But SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** The other allowed parameters to sqlite3_mutex_alloc() each return
+** a pointer to a static preexisting mutex.  Six static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  But for the static
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+*/
+static sqlite3_mutex *pthreadMutexAlloc(int iType){
+  static sqlite3_mutex staticMutexes[] = {
+    SQLITE3_MUTEX_INITIALIZER(2),
+    SQLITE3_MUTEX_INITIALIZER(3),
+    SQLITE3_MUTEX_INITIALIZER(4),
+    SQLITE3_MUTEX_INITIALIZER(5),
+    SQLITE3_MUTEX_INITIALIZER(6),
+    SQLITE3_MUTEX_INITIALIZER(7),
+    SQLITE3_MUTEX_INITIALIZER(8),
+    SQLITE3_MUTEX_INITIALIZER(9),
+    SQLITE3_MUTEX_INITIALIZER(10),
+    SQLITE3_MUTEX_INITIALIZER(11),
+    SQLITE3_MUTEX_INITIALIZER(12),
+    SQLITE3_MUTEX_INITIALIZER(13)
+  };
+  sqlite3_mutex *p;
+  switch( iType ){
+    case SQLITE_MUTEX_RECURSIVE: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+        /* If recursive mutexes are not available, we will have to
+        ** build our own.  See below. */
+        pthread_mutex_init(&p->mutex, 0);
+#else
+        /* Use a recursive mutex if it is available */
+        pthread_mutexattr_t recursiveAttr;
+        pthread_mutexattr_init(&recursiveAttr);
+        pthread_mutexattr_settype(&recursiveAttr, PTHREAD_MUTEX_RECURSIVE);
+        pthread_mutex_init(&p->mutex, &recursiveAttr);
+        pthread_mutexattr_destroy(&recursiveAttr);
+#endif
+#if SQLITE_MUTEX_NREF || defined(SQLITE_ENABLE_API_ARMOR)
+        p->id = SQLITE_MUTEX_RECURSIVE;
+#endif
+      }
+      break;
+    }
+    case SQLITE_MUTEX_FAST: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+        pthread_mutex_init(&p->mutex, 0);
+#if SQLITE_MUTEX_NREF || defined(SQLITE_ENABLE_API_ARMOR)
+        p->id = SQLITE_MUTEX_FAST;
+#endif
+      }
+      break;
+    }
+    default: {
+#ifdef SQLITE_ENABLE_API_ARMOR
+      if( iType-2<0 || iType-2>=ArraySize(staticMutexes) ){
+        (void)SQLITE_MISUSE_BKPT;
+        return 0;
+      }
+#endif
+      p = &staticMutexes[iType-2];
+      break;
+    }
+  }
+#if SQLITE_MUTEX_NREF || defined(SQLITE_ENABLE_API_ARMOR)
+  assert( p==0 || p->id==iType );
+#endif
+  return p;
+}
+
+
+/*
+** This routine deallocates a previously
+** allocated mutex.  SQLite is careful to deallocate every
+** mutex that it allocates.
+*/
+static void pthreadMutexFree(sqlite3_mutex *p){
+  assert( p->nRef==0 );
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE )
+#endif
+  {
+    pthread_mutex_destroy(&p->mutex);
+    sqlite3_free(p);
+  }
+#ifdef SQLITE_ENABLE_API_ARMOR
+  else{
+    (void)SQLITE_MISUSE_BKPT;
+  }
+#endif
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+static void pthreadMutexEnter(sqlite3_mutex *p){
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || pthreadMutexNotheld(p) );
+
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  /* If recursive mutexes are not available, then we have to grow
+  ** our own.  This implementation assumes that pthread_equal()
+  ** is atomic - that it cannot be deceived into thinking self
+  ** and p->owner are equal if p->owner changes between two values
+  ** that are not equal to self while the comparison is taking place.
+  ** This implementation also assumes a coherent cache - that
+  ** separate processes cannot read different values from the same
+  ** address at the same time.  If either of these two conditions
+  ** are not met, then the mutexes will fail and problems will result.
+  */
+  {
+    pthread_t self = pthread_self();
+    if( p->nRef>0 && pthread_equal(p->owner, self) ){
+      p->nRef++;
+    }else{
+      pthread_mutex_lock(&p->mutex);
+      assert( p->nRef==0 );
+      p->owner = self;
+      p->nRef = 1;
+    }
+  }
+#else
+  /* Use the built-in recursive mutexes if they are available.
+  */
+  pthread_mutex_lock(&p->mutex);
+#if SQLITE_MUTEX_NREF
+  assert( p->nRef>0 || p->owner==0 );
+  p->owner = pthread_self();
+  p->nRef++;
+#endif
+#endif
+
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
+}
+static int pthreadMutexTry(sqlite3_mutex *p){
+  int rc;
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || pthreadMutexNotheld(p) );
+
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  /* If recursive mutexes are not available, then we have to grow
+  ** our own.  This implementation assumes that pthread_equal()
+  ** is atomic - that it cannot be deceived into thinking self
+  ** and p->owner are equal if p->owner changes between two values
+  ** that are not equal to self while the comparison is taking place.
+  ** This implementation also assumes a coherent cache - that
+  ** separate processes cannot read different values from the same
+  ** address at the same time.  If either of these two conditions
+  ** are not met, then the mutexes will fail and problems will result.
+  */
+  {
+    pthread_t self = pthread_self();
+    if( p->nRef>0 && pthread_equal(p->owner, self) ){
+      p->nRef++;
+      rc = SQLITE_OK;
+    }else if( pthread_mutex_trylock(&p->mutex)==0 ){
+      assert( p->nRef==0 );
+      p->owner = self;
+      p->nRef = 1;
+      rc = SQLITE_OK;
+    }else{
+      rc = SQLITE_BUSY;
+    }
+  }
+#else
+  /* Use the built-in recursive mutexes if they are available.
+  */
+  if( pthread_mutex_trylock(&p->mutex)==0 ){
+#if SQLITE_MUTEX_NREF
+    p->owner = pthread_self();
+    p->nRef++;
+#endif
+    rc = SQLITE_OK;
+  }else{
+    rc = SQLITE_BUSY;
+  }
+#endif
+
+#ifdef SQLITE_DEBUG
+  if( rc==SQLITE_OK && p->trace ){
+    printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
+  return rc;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+static void pthreadMutexLeave(sqlite3_mutex *p){
+  assert( pthreadMutexHeld(p) );
+#if SQLITE_MUTEX_NREF
+  p->nRef--;
+  if( p->nRef==0 ) p->owner = 0;
+#endif
+  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
+
+#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
+  if( p->nRef==0 ){
+    pthread_mutex_unlock(&p->mutex);
+  }
+#else
+  pthread_mutex_unlock(&p->mutex);
+#endif
+
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
+  }
+#endif
+}
+
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    pthreadMutexInit,
+    pthreadMutexEnd,
+    pthreadMutexAlloc,
+    pthreadMutexFree,
+    pthreadMutexEnter,
+    pthreadMutexTry,
+    pthreadMutexLeave,
+#ifdef SQLITE_DEBUG
+    pthreadMutexHeld,
+    pthreadMutexNotheld
+#else
+    0,
+    0
+#endif
+  };
+
+  return &sMutex;
+}
+
+#endif /* SQLITE_MUTEX_PTHREADS */
+
+/************** End of mutex_unix.c ******************************************/
+/************** Begin file mutex_w32.c ***************************************/
+/*
+** 2007 August 14
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C functions that implement mutexes for Win32.
+*/
+/* #include "sqliteInt.h" */
+
+#if SQLITE_OS_WIN
+/*
+** Include code that is common to all os_*.c files
+*/
+/* #include "os_common.h" */
+
+/*
+** Include the header file for the Windows VFS.
+*/
+/************** Include os_win.h in the middle of mutex_w32.c ****************/
+/************** Begin file os_win.h ******************************************/
+/*
+** 2013 November 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to Windows.
+*/
+#ifndef SQLITE_OS_WIN_H
+#define SQLITE_OS_WIN_H
+
+/*
+** Include the primary Windows SDK header file.
+*/
+#include "windows.h"
+
+#ifdef __CYGWIN__
+# include <sys/cygwin.h>
+# include <errno.h> /* amalgamator: dontcache */
+#endif
+
+/*
+** Determine if we are dealing with Windows NT.
+**
+** We ought to be able to determine if we are compiling for Windows 9x or
+** Windows NT using the _WIN32_WINNT macro as follows:
+**
+** #if defined(_WIN32_WINNT)
+** # define SQLITE_OS_WINNT 1
+** #else
+** # define SQLITE_OS_WINNT 0
+** #endif
+**
+** However, Visual Studio 2005 does not set _WIN32_WINNT by default, as
+** it ought to, so the above test does not work.  We'll just assume that
+** everything is Windows NT unless the programmer explicitly says otherwise
+** by setting SQLITE_OS_WINNT to 0.
+*/
+#if SQLITE_OS_WIN && !defined(SQLITE_OS_WINNT)
+# define SQLITE_OS_WINNT 1
+#endif
+
+/*
+** Determine if we are dealing with Windows CE - which has a much reduced
+** API.
+*/
+#if defined(_WIN32_WCE)
+# define SQLITE_OS_WINCE 1
+#else
+# define SQLITE_OS_WINCE 0
+#endif
+
+/*
+** Determine if we are dealing with WinRT, which provides only a subset of
+** the full Win32 API.
+*/
+#if !defined(SQLITE_OS_WINRT)
+# define SQLITE_OS_WINRT 0
+#endif
+
+/*
+** For WinCE, some API function parameters do not appear to be declared as
+** volatile.
+*/
+#if SQLITE_OS_WINCE
+# define SQLITE_WIN32_VOLATILE
+#else
+# define SQLITE_WIN32_VOLATILE volatile
+#endif
+
+/*
+** For some Windows sub-platforms, the _beginthreadex() / _endthreadex()
+** functions are not available (e.g. those not using MSVC, Cygwin, etc).
+*/
+#if SQLITE_OS_WIN && !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && \
+    SQLITE_THREADSAFE>0 && !defined(__CYGWIN__)
+# define SQLITE_OS_WIN_THREADS 1
+#else
+# define SQLITE_OS_WIN_THREADS 0
+#endif
+
+#endif /* SQLITE_OS_WIN_H */
+
+/************** End of os_win.h **********************************************/
+/************** Continuing where we left off in mutex_w32.c ******************/
+#endif
+
+/*
+** The code in this file is only used if we are compiling multithreaded
+** on a Win32 system.
+*/
+#ifdef SQLITE_MUTEX_W32
+
+/*
+** Each recursive mutex is an instance of the following structure.
+*/
+struct sqlite3_mutex {
+  CRITICAL_SECTION mutex;    /* Mutex controlling the lock */
+  int id;                    /* Mutex type */
+#ifdef SQLITE_DEBUG
+  volatile int nRef;         /* Number of entrances */
+  volatile DWORD owner;      /* Thread holding this mutex */
+  volatile LONG trace;       /* True to trace changes */
+#endif
+};
+
+/*
+** These are the initializer values used when declaring a "static" mutex
+** on Win32.  It should be noted that all mutexes require initialization
+** on the Win32 platform.
+*/
+#define SQLITE_W32_MUTEX_INITIALIZER { 0 }
+
+#ifdef SQLITE_DEBUG
+#define SQLITE3_MUTEX_INITIALIZER(id) { SQLITE_W32_MUTEX_INITIALIZER, id, \
+                                    0L, (DWORD)0, 0 }
+#else
+#define SQLITE3_MUTEX_INITIALIZER(id) { SQLITE_W32_MUTEX_INITIALIZER, id }
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
+** intended for use only inside assert() statements.
+*/
+static int winMutexHeld(sqlite3_mutex *p){
+  return p->nRef!=0 && p->owner==GetCurrentThreadId();
+}
+
+static int winMutexNotheld2(sqlite3_mutex *p, DWORD tid){
+  return p->nRef==0 || p->owner!=tid;
+}
+
+static int winMutexNotheld(sqlite3_mutex *p){
+  DWORD tid = GetCurrentThreadId();
+  return winMutexNotheld2(p, tid);
+}
+#endif
+
+/*
+** Try to provide a memory barrier operation, needed for initialization
+** and also for the xShmBarrier method of the VFS in cases when SQLite is
+** compiled without mutexes (SQLITE_THREADSAFE=0).
+*/
+SQLITE_PRIVATE void sqlite3MemoryBarrier(void){
+#if defined(SQLITE_MEMORY_BARRIER)
+  SQLITE_MEMORY_BARRIER;
+#elif defined(__GNUC__)
+  __sync_synchronize();
+#elif MSVC_VERSION>=1400
+  _ReadWriteBarrier();
+#elif defined(MemoryBarrier)
+  MemoryBarrier();
+#endif
+}
+
+/*
+** Initialize and deinitialize the mutex subsystem.
+*/
+static sqlite3_mutex winMutex_staticMutexes[] = {
+  SQLITE3_MUTEX_INITIALIZER(2),
+  SQLITE3_MUTEX_INITIALIZER(3),
+  SQLITE3_MUTEX_INITIALIZER(4),
+  SQLITE3_MUTEX_INITIALIZER(5),
+  SQLITE3_MUTEX_INITIALIZER(6),
+  SQLITE3_MUTEX_INITIALIZER(7),
+  SQLITE3_MUTEX_INITIALIZER(8),
+  SQLITE3_MUTEX_INITIALIZER(9),
+  SQLITE3_MUTEX_INITIALIZER(10),
+  SQLITE3_MUTEX_INITIALIZER(11),
+  SQLITE3_MUTEX_INITIALIZER(12),
+  SQLITE3_MUTEX_INITIALIZER(13)
+};
+
+static int winMutex_isInit = 0;
+static int winMutex_isNt = -1; /* <0 means "need to query" */
+
+/* As the winMutexInit() and winMutexEnd() functions are called as part
+** of the sqlite3_initialize() and sqlite3_shutdown() processing, the
+** "interlocked" magic used here is probably not strictly necessary.
+*/
+static LONG SQLITE_WIN32_VOLATILE winMutex_lock = 0;
+
+SQLITE_API int sqlite3_win32_is_nt(void); /* os_win.c */
+SQLITE_API void sqlite3_win32_sleep(DWORD milliseconds); /* os_win.c */
+
+static int winMutexInit(void){
+  /* The first to increment to 1 does actual initialization */
+  if( InterlockedCompareExchange(&winMutex_lock, 1, 0)==0 ){
+    int i;
+    for(i=0; i<ArraySize(winMutex_staticMutexes); i++){
+#if SQLITE_OS_WINRT
+      InitializeCriticalSectionEx(&winMutex_staticMutexes[i].mutex, 0, 0);
+#else
+      InitializeCriticalSection(&winMutex_staticMutexes[i].mutex);
+#endif
+    }
+    winMutex_isInit = 1;
+  }else{
+    /* Another thread is (in the process of) initializing the static
+    ** mutexes */
+    while( !winMutex_isInit ){
+      sqlite3_win32_sleep(1);
+    }
+  }
+  return SQLITE_OK;
+}
+
+static int winMutexEnd(void){
+  /* The first to decrement to 0 does actual shutdown
+  ** (which should be the last to shutdown.) */
+  if( InterlockedCompareExchange(&winMutex_lock, 0, 1)==1 ){
+    if( winMutex_isInit==1 ){
+      int i;
+      for(i=0; i<ArraySize(winMutex_staticMutexes); i++){
+        DeleteCriticalSection(&winMutex_staticMutexes[i].mutex);
+      }
+      winMutex_isInit = 0;
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it.  If it returns NULL
+** that means that a mutex could not be allocated.  SQLite
+** will unwind its stack and return an error.  The argument
+** to sqlite3_mutex_alloc() is one of these integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MAIN
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_OPEN
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
+** <li>  SQLITE_MUTEX_STATIC_APP1
+** <li>  SQLITE_MUTEX_STATIC_APP2
+** <li>  SQLITE_MUTEX_STATIC_APP3
+** <li>  SQLITE_MUTEX_STATIC_VFS1
+** <li>  SQLITE_MUTEX_STATIC_VFS2
+** <li>  SQLITE_MUTEX_STATIC_VFS3
+** </ul>
+**
+** The first two constants cause sqlite3_mutex_alloc() to create
+** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  But SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** The other allowed parameters to sqlite3_mutex_alloc() each return
+** a pointer to a static preexisting mutex.  Six static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  But for the static
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+*/
+static sqlite3_mutex *winMutexAlloc(int iType){
+  sqlite3_mutex *p;
+
+  switch( iType ){
+    case SQLITE_MUTEX_FAST:
+    case SQLITE_MUTEX_RECURSIVE: {
+      p = sqlite3MallocZero( sizeof(*p) );
+      if( p ){
+        p->id = iType;
+#ifdef SQLITE_DEBUG
+#ifdef SQLITE_WIN32_MUTEX_TRACE_DYNAMIC
+        p->trace = 1;
+#endif
+#endif
+#if SQLITE_OS_WINRT
+        InitializeCriticalSectionEx(&p->mutex, 0, 0);
+#else
+        InitializeCriticalSection(&p->mutex);
+#endif
+      }
+      break;
+    }
+    default: {
+#ifdef SQLITE_ENABLE_API_ARMOR
+      if( iType-2<0 || iType-2>=ArraySize(winMutex_staticMutexes) ){
+        (void)SQLITE_MISUSE_BKPT;
+        return 0;
+      }
+#endif
+      p = &winMutex_staticMutexes[iType-2];
+#ifdef SQLITE_DEBUG
+#ifdef SQLITE_WIN32_MUTEX_TRACE_STATIC
+      InterlockedCompareExchange(&p->trace, 1, 0);
+#endif
+#endif
+      break;
+    }
+  }
+  assert( p==0 || p->id==iType );
+  return p;
+}
+
+
+/*
+** This routine deallocates a previously
+** allocated mutex.  SQLite is careful to deallocate every
+** mutex that it allocates.
+*/
+static void winMutexFree(sqlite3_mutex *p){
+  assert( p );
+  assert( p->nRef==0 && p->owner==0 );
+  if( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE ){
+    DeleteCriticalSection(&p->mutex);
+    sqlite3_free(p);
+  }else{
+#ifdef SQLITE_ENABLE_API_ARMOR
+    (void)SQLITE_MISUSE_BKPT;
+#endif
+  }
+}
+
+/*
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  The sqlite3_mutex_try() interface returns SQLITE_OK
+** upon successful entry.  Mutexes created using SQLITE_MUTEX_RECURSIVE can
+** be entered multiple times by the same thread.  In such cases the,
+** mutex must be exited an equal number of times before another thread
+** can enter.  If the same thread tries to enter any other kind of mutex
+** more than once, the behavior is undefined.
+*/
+static void winMutexEnter(sqlite3_mutex *p){
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  DWORD tid = GetCurrentThreadId();
+#endif
+#ifdef SQLITE_DEBUG
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
+#else
+  assert( p );
+#endif
+  assert( winMutex_isInit==1 );
+  EnterCriticalSection(&p->mutex);
+#ifdef SQLITE_DEBUG
+  assert( p->nRef>0 || p->owner==0 );
+  p->owner = tid;
+  p->nRef++;
+  if( p->trace ){
+    OSTRACE(("ENTER-MUTEX tid=%lu, mutex(%d)=%p (%d), nRef=%d\n",
+             tid, p->id, p, p->trace, p->nRef));
+  }
+#endif
+}
+
+static int winMutexTry(sqlite3_mutex *p){
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  DWORD tid = GetCurrentThreadId();
+#endif
+  int rc = SQLITE_BUSY;
+  assert( p );
+  assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
+  /*
+  ** The sqlite3_mutex_try() routine is very rarely used, and when it
+  ** is used it is merely an optimization.  So it is OK for it to always
+  ** fail.
+  **
+  ** The TryEnterCriticalSection() interface is only available on WinNT.
+  ** And some windows compilers complain if you try to use it without
+  ** first doing some #defines that prevent SQLite from building on Win98.
+  ** For that reason, we will omit this optimization for now.  See
+  ** ticket #2685.
+  */
+#if defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x0400
+  assert( winMutex_isInit==1 );
+  assert( winMutex_isNt>=-1 && winMutex_isNt<=1 );
+  if( winMutex_isNt<0 ){
+    winMutex_isNt = sqlite3_win32_is_nt();
+  }
+  assert( winMutex_isNt==0 || winMutex_isNt==1 );
+  if( winMutex_isNt && TryEnterCriticalSection(&p->mutex) ){
+#ifdef SQLITE_DEBUG
+    p->owner = tid;
+    p->nRef++;
+#endif
+    rc = SQLITE_OK;
+  }
+#else
+  UNUSED_PARAMETER(p);
+#endif
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    OSTRACE(("TRY-MUTEX tid=%lu, mutex(%d)=%p (%d), owner=%lu, nRef=%d, rc=%s\n",
+             tid, p->id, p, p->trace, p->owner, p->nRef, sqlite3ErrName(rc)));
+  }
+#endif
+  return rc;
+}
+
+/*
+** The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.  The behavior
+** is undefined if the mutex is not currently entered or
+** is not currently allocated.  SQLite will never do either.
+*/
+static void winMutexLeave(sqlite3_mutex *p){
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  DWORD tid = GetCurrentThreadId();
+#endif
+  assert( p );
+#ifdef SQLITE_DEBUG
+  assert( p->nRef>0 );
+  assert( p->owner==tid );
+  p->nRef--;
+  if( p->nRef==0 ) p->owner = 0;
+  assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
+#endif
+  assert( winMutex_isInit==1 );
+  LeaveCriticalSection(&p->mutex);
+#ifdef SQLITE_DEBUG
+  if( p->trace ){
+    OSTRACE(("LEAVE-MUTEX tid=%lu, mutex(%d)=%p (%d), nRef=%d\n",
+             tid, p->id, p, p->trace, p->nRef));
+  }
+#endif
+}
+
+SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
+  static const sqlite3_mutex_methods sMutex = {
+    winMutexInit,
+    winMutexEnd,
+    winMutexAlloc,
+    winMutexFree,
+    winMutexEnter,
+    winMutexTry,
+    winMutexLeave,
+#ifdef SQLITE_DEBUG
+    winMutexHeld,
+    winMutexNotheld
+#else
+    0,
+    0
+#endif
+  };
+  return &sMutex;
+}
+
+#endif /* SQLITE_MUTEX_W32 */
+
+/************** End of mutex_w32.c *******************************************/
+/************** Begin file malloc.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** Memory allocation functions used throughout sqlite.
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdarg.h> */
+
+/*
+** Attempt to release up to n bytes of non-essential memory currently
+** held by SQLite. An example of non-essential memory is memory used to
+** cache database pages that are not currently in use.
+*/
+SQLITE_API int sqlite3_release_memory(int n){
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  return sqlite3PcacheReleaseMemory(n);
+#else
+  /* IMPLEMENTATION-OF: R-34391-24921 The sqlite3_release_memory() routine
+  ** is a no-op returning zero if SQLite is not compiled with
+  ** SQLITE_ENABLE_MEMORY_MANAGEMENT. */
+  UNUSED_PARAMETER(n);
+  return 0;
+#endif
+}
+
+/*
+** Default value of the hard heap limit.  0 means "no limit".
+*/
+#ifndef SQLITE_MAX_MEMORY
+# define SQLITE_MAX_MEMORY 0
+#endif
+
+/*
+** State information local to the memory allocation subsystem.
+*/
+static SQLITE_WSD struct Mem0Global {
+  sqlite3_mutex *mutex;         /* Mutex to serialize access */
+  sqlite3_int64 alarmThreshold; /* The soft heap limit */
+  sqlite3_int64 hardLimit;      /* The hard upper bound on memory */
+
+  /*
+  ** True if heap is nearly "full" where "full" is defined by the
+  ** sqlite3_soft_heap_limit() setting.
+  */
+  int nearlyFull;
+} mem0 = { 0, SQLITE_MAX_MEMORY, SQLITE_MAX_MEMORY, 0 };
+
+#define mem0 GLOBAL(struct Mem0Global, mem0)
+
+/*
+** Return the memory allocator mutex. sqlite3_status() needs it.
+*/
+SQLITE_PRIVATE sqlite3_mutex *sqlite3MallocMutex(void){
+  return mem0.mutex;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Deprecated external interface.  It used to set an alarm callback
+** that was invoked when memory usage grew too large.  Now it is a
+** no-op.
+*/
+SQLITE_API int sqlite3_memory_alarm(
+  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
+  void *pArg,
+  sqlite3_int64 iThreshold
+){
+  (void)xCallback;
+  (void)pArg;
+  (void)iThreshold;
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Set the soft heap-size limit for the library.  An argument of
+** zero disables the limit.  A negative argument is a no-op used to
+** obtain the return value.
+**
+** The return value is the value of the heap limit just before this
+** interface was called.
+**
+** If the hard heap limit is enabled, then the soft heap limit cannot
+** be disabled nor raised above the hard heap limit.
+*/
+SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){
+  sqlite3_int64 priorLimit;
+  sqlite3_int64 excess;
+  sqlite3_int64 nUsed;
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return -1;
+#endif
+  sqlite3_mutex_enter(mem0.mutex);
+  priorLimit = mem0.alarmThreshold;
+  if( n<0 ){
+    sqlite3_mutex_leave(mem0.mutex);
+    return priorLimit;
+  }
+  if( mem0.hardLimit>0 && (n>mem0.hardLimit || n==0) ){
+    n = mem0.hardLimit;
+  }
+  mem0.alarmThreshold = n;
+  nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
+  AtomicStore(&mem0.nearlyFull, n>0 && n<=nUsed);
+  sqlite3_mutex_leave(mem0.mutex);
+  excess = sqlite3_memory_used() - n;
+  if( excess>0 ) sqlite3_release_memory((int)(excess & 0x7fffffff));
+  return priorLimit;
+}
+SQLITE_API void sqlite3_soft_heap_limit(int n){
+  if( n<0 ) n = 0;
+  sqlite3_soft_heap_limit64(n);
+}
+
+/*
+** Set the hard heap-size limit for the library. An argument of zero
+** disables the hard heap limit.  A negative argument is a no-op used
+** to obtain the return value without affecting the hard heap limit.
+**
+** The return value is the value of the hard heap limit just prior to
+** calling this interface.
+**
+** Setting the hard heap limit will also activate the soft heap limit
+** and constrain the soft heap limit to be no more than the hard heap
+** limit.
+*/
+SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 n){
+  sqlite3_int64 priorLimit;
+#ifndef SQLITE_OMIT_AUTOINIT
+  int rc = sqlite3_initialize();
+  if( rc ) return -1;
+#endif
+  sqlite3_mutex_enter(mem0.mutex);
+  priorLimit = mem0.hardLimit;
+  if( n>=0 ){
+    mem0.hardLimit = n;
+    if( n<mem0.alarmThreshold || mem0.alarmThreshold==0 ){
+      mem0.alarmThreshold = n;
+    }
+  }
+  sqlite3_mutex_leave(mem0.mutex);
+  return priorLimit;
+}
+
+
+/*
+** Initialize the memory allocation subsystem.
+*/
+SQLITE_PRIVATE int sqlite3MallocInit(void){
+  int rc;
+  if( sqlite3GlobalConfig.m.xMalloc==0 ){
+    sqlite3MemSetDefault();
+  }
+  mem0.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  if( sqlite3GlobalConfig.pPage==0 || sqlite3GlobalConfig.szPage<512
+      || sqlite3GlobalConfig.nPage<=0 ){
+    sqlite3GlobalConfig.pPage = 0;
+    sqlite3GlobalConfig.szPage = 0;
+  }
+  rc = sqlite3GlobalConfig.m.xInit(sqlite3GlobalConfig.m.pAppData);
+  if( rc!=SQLITE_OK ) memset(&mem0, 0, sizeof(mem0));
+  return rc;
+}
+
+/*
+** Return true if the heap is currently under memory pressure - in other
+** words if the amount of heap used is close to the limit set by
+** sqlite3_soft_heap_limit().
+*/
+SQLITE_PRIVATE int sqlite3HeapNearlyFull(void){
+  return AtomicLoad(&mem0.nearlyFull);
+}
+
+/*
+** Deinitialize the memory allocation subsystem.
+*/
+SQLITE_PRIVATE void sqlite3MallocEnd(void){
+  if( sqlite3GlobalConfig.m.xShutdown ){
+    sqlite3GlobalConfig.m.xShutdown(sqlite3GlobalConfig.m.pAppData);
+  }
+  memset(&mem0, 0, sizeof(mem0));
+}
+
+/*
+** Return the amount of memory currently checked out.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void){
+  sqlite3_int64 res, mx;
+  sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &res, &mx, 0);
+  return res;
+}
+
+/*
+** Return the maximum amount of memory that has ever been
+** checked out since either the beginning of this process
+** or since the most recent reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
+  sqlite3_int64 res, mx;
+  sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &res, &mx, resetFlag);
+  return mx;
+}
+
+/*
+** Trigger the alarm
+*/
+static void sqlite3MallocAlarm(int nByte){
+  if( mem0.alarmThreshold<=0 ) return;
+  sqlite3_mutex_leave(mem0.mutex);
+  sqlite3_release_memory(nByte);
+  sqlite3_mutex_enter(mem0.mutex);
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** This routine is called whenever an out-of-memory condition is seen,
+** It's only purpose to to serve as a breakpoint for gdb or similar
+** code debuggers when working on out-of-memory conditions, for example
+** caused by PRAGMA hard_heap_limit=N.
+*/
+static SQLITE_NOINLINE void test_oom_breakpoint(u64 n){
+  static u64 nOomFault = 0;
+  nOomFault += n;
+  /* The assert() is never reached in a human lifetime.  It  is here mostly
+  ** to prevent code optimizers from optimizing out this function. */
+  assert( (nOomFault>>32) < 0xffffffff );
+}
+#else
+# define test_oom_breakpoint(X)   /* No-op for production builds */
+#endif
+
+/*
+** Do a memory allocation with statistics and alarms.  Assume the
+** lock is already held.
+*/
+static void mallocWithAlarm(int n, void **pp){
+  void *p;
+  int nFull;
+  assert( sqlite3_mutex_held(mem0.mutex) );
+  assert( n>0 );
+
+  /* In Firefox (circa 2017-02-08), xRoundup() is remapped to an internal
+  ** implementation of malloc_good_size(), which must be called in debug
+  ** mode and specifically when the DMD "Dark Matter Detector" is enabled
+  ** or else a crash results.  Hence, do not attempt to optimize out the
+  ** following xRoundup() call. */
+  nFull = sqlite3GlobalConfig.m.xRoundup(n);
+
+  sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, n);
+  if( mem0.alarmThreshold>0 ){
+    sqlite3_int64 nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
+    if( nUsed >= mem0.alarmThreshold - nFull ){
+      AtomicStore(&mem0.nearlyFull, 1);
+      sqlite3MallocAlarm(nFull);
+      if( mem0.hardLimit ){
+        nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
+        if( nUsed >= mem0.hardLimit - nFull ){
+          test_oom_breakpoint(1);
+          *pp = 0;
+          return;
+        }
+      }
+    }else{
+      AtomicStore(&mem0.nearlyFull, 0);
+    }
+  }
+  p = sqlite3GlobalConfig.m.xMalloc(nFull);
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+  if( p==0 && mem0.alarmThreshold>0 ){
+    sqlite3MallocAlarm(nFull);
+    p = sqlite3GlobalConfig.m.xMalloc(nFull);
+  }
+#endif
+  if( p ){
+    nFull = sqlite3MallocSize(p);
+    sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nFull);
+    sqlite3StatusUp(SQLITE_STATUS_MALLOC_COUNT, 1);
+  }
+  *pp = p;
+}
+
+/*
+** Maximum size of any single memory allocation.
+**
+** This is not a limit on the total amount of memory used.  This is
+** a limit on the size parameter to sqlite3_malloc() and sqlite3_realloc().
+**
+** The upper bound is slightly less than 2GiB:  0x7ffffeff == 2,147,483,391
+** This provides a 256-byte safety margin for defense against 32-bit
+** signed integer overflow bugs when computing memory allocation sizes.
+** Paranoid applications might want to reduce the maximum allocation size
+** further for an even larger safety margin.  0x3fffffff or 0x0fffffff
+** or even smaller would be reasonable upper bounds on the size of a memory
+** allocations for most applications.
+*/
+#ifndef SQLITE_MAX_ALLOCATION_SIZE
+# define SQLITE_MAX_ALLOCATION_SIZE  2147483391
+#endif
+#if SQLITE_MAX_ALLOCATION_SIZE>2147483391
+# error Maximum size for SQLITE_MAX_ALLOCATION_SIZE is 2147483391
+#endif
+
+/*
+** Allocate memory.  This routine is like sqlite3_malloc() except that it
+** assumes the memory subsystem has already been initialized.
+*/
+SQLITE_PRIVATE void *sqlite3Malloc(u64 n){
+  void *p;
+  if( n==0 || n>SQLITE_MAX_ALLOCATION_SIZE ){
+    p = 0;
+  }else if( sqlite3GlobalConfig.bMemstat ){
+    sqlite3_mutex_enter(mem0.mutex);
+    mallocWithAlarm((int)n, &p);
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    p = sqlite3GlobalConfig.m.xMalloc((int)n);
+  }
+  assert( EIGHT_BYTE_ALIGNMENT(p) );  /* IMP: R-11148-40995 */
+  return p;
+}
+
+/*
+** This version of the memory allocation is for use by the application.
+** First make sure the memory subsystem is initialized, then do the
+** allocation.
+*/
+SQLITE_API void *sqlite3_malloc(int n){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return n<=0 ? 0 : sqlite3Malloc(n);
+}
+SQLITE_API void *sqlite3_malloc64(sqlite3_uint64 n){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return sqlite3Malloc(n);
+}
+
+/*
+** TRUE if p is a lookaside memory allocation from db
+*/
+#ifndef SQLITE_OMIT_LOOKASIDE
+static int isLookaside(sqlite3 *db, const void *p){
+  return SQLITE_WITHIN(p, db->lookaside.pStart, db->lookaside.pTrueEnd);
+}
+#else
+#define isLookaside(A,B) 0
+#endif
+
+/*
+** Return the size of a memory allocation previously obtained from
+** sqlite3Malloc() or sqlite3_malloc().
+*/
+SQLITE_PRIVATE int sqlite3MallocSize(const void *p){
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  return sqlite3GlobalConfig.m.xSize((void*)p);
+}
+static int lookasideMallocSize(sqlite3 *db, const void *p){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  return p<db->lookaside.pMiddle ? db->lookaside.szTrue : LOOKASIDE_SMALL;
+#else
+  return db->lookaside.szTrue;
+#endif
+}
+SQLITE_PRIVATE int sqlite3DbMallocSize(sqlite3 *db, const void *p){
+  assert( p!=0 );
+#ifdef SQLITE_DEBUG
+  if( db==0 ){
+    assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  }else if( !isLookaside(db,p) ){
+    assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+    assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  }
+#endif
+  if( db ){
+    if( ((uptr)p)<(uptr)(db->lookaside.pTrueEnd) ){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+      if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
+        assert( sqlite3_mutex_held(db->mutex) );
+        return LOOKASIDE_SMALL;
+      }
+#endif
+      if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
+        assert( sqlite3_mutex_held(db->mutex) );
+        return db->lookaside.szTrue;
+      }
+    }
+  }
+  return sqlite3GlobalConfig.m.xSize((void*)p);
+}
+SQLITE_API sqlite3_uint64 sqlite3_msize(void *p){
+  assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  return p ? sqlite3GlobalConfig.m.xSize(p) : 0;
+}
+
+/*
+** Free memory previously obtained from sqlite3Malloc().
+*/
+SQLITE_API void sqlite3_free(void *p){
+  if( p==0 ) return;  /* IMP: R-49053-54554 */
+  assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
+  if( sqlite3GlobalConfig.bMemstat ){
+    sqlite3_mutex_enter(mem0.mutex);
+    sqlite3StatusDown(SQLITE_STATUS_MEMORY_USED, sqlite3MallocSize(p));
+    sqlite3StatusDown(SQLITE_STATUS_MALLOC_COUNT, 1);
+    sqlite3GlobalConfig.m.xFree(p);
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    sqlite3GlobalConfig.m.xFree(p);
+  }
+}
+
+/*
+** Add the size of memory allocation "p" to the count in
+** *db->pnBytesFreed.
+*/
+static SQLITE_NOINLINE void measureAllocationSize(sqlite3 *db, void *p){
+  *db->pnBytesFreed += sqlite3DbMallocSize(db,p);
+}
+
+/*
+** Free memory that might be associated with a particular database
+** connection.  Calling sqlite3DbFree(D,X) for X==0 is a harmless no-op.
+** The sqlite3DbFreeNN(D,X) version requires that X be non-NULL.
+*/
+SQLITE_PRIVATE void sqlite3DbFreeNN(sqlite3 *db, void *p){
+  assert( db==0 || sqlite3_mutex_held(db->mutex) );
+  assert( p!=0 );
+  if( db ){
+    if( ((uptr)p)<(uptr)(db->lookaside.pEnd) ){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+      if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
+        LookasideSlot *pBuf = (LookasideSlot*)p;
+        assert( db->pnBytesFreed==0 );
+#ifdef SQLITE_DEBUG
+        memset(p, 0xaa, LOOKASIDE_SMALL);  /* Trash freed content */
+#endif
+        pBuf->pNext = db->lookaside.pSmallFree;
+        db->lookaside.pSmallFree = pBuf;
+        return;
+      }
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+      if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
+        LookasideSlot *pBuf = (LookasideSlot*)p;
+        assert( db->pnBytesFreed==0 );
+#ifdef SQLITE_DEBUG
+        memset(p, 0xaa, db->lookaside.szTrue);  /* Trash freed content */
+#endif
+        pBuf->pNext = db->lookaside.pFree;
+        db->lookaside.pFree = pBuf;
+        return;
+      }
+    }
+    if( db->pnBytesFreed ){
+      measureAllocationSize(db, p);
+      return;
+    }
+  }
+  assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
+  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+  sqlite3_free(p);
+}
+SQLITE_PRIVATE void sqlite3DbNNFreeNN(sqlite3 *db, void *p){
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( p!=0 );
+  if( ((uptr)p)<(uptr)(db->lookaside.pEnd) ){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+    if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
+      LookasideSlot *pBuf = (LookasideSlot*)p;
+      assert( db->pnBytesFreed==0 );
+#ifdef SQLITE_DEBUG
+      memset(p, 0xaa, LOOKASIDE_SMALL);  /* Trash freed content */
+#endif
+      pBuf->pNext = db->lookaside.pSmallFree;
+      db->lookaside.pSmallFree = pBuf;
+      return;
+    }
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+    if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
+      LookasideSlot *pBuf = (LookasideSlot*)p;
+      assert( db->pnBytesFreed==0 );
+#ifdef SQLITE_DEBUG
+      memset(p, 0xaa, db->lookaside.szTrue);  /* Trash freed content */
+#endif
+      pBuf->pNext = db->lookaside.pFree;
+      db->lookaside.pFree = pBuf;
+      return;
+    }
+  }
+  if( db->pnBytesFreed ){
+    measureAllocationSize(db, p);
+    return;
+  }
+  assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+  sqlite3_free(p);
+}
+SQLITE_PRIVATE void sqlite3DbFree(sqlite3 *db, void *p){
+  assert( db==0 || sqlite3_mutex_held(db->mutex) );
+  if( p ) sqlite3DbFreeNN(db, p);
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+SQLITE_PRIVATE void *sqlite3Realloc(void *pOld, u64 nBytes){
+  int nOld, nNew, nDiff;
+  void *pNew;
+  assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );
+  assert( sqlite3MemdebugNoType(pOld, (u8)~MEMTYPE_HEAP) );
+  if( pOld==0 ){
+    return sqlite3Malloc(nBytes); /* IMP: R-04300-56712 */
+  }
+  if( nBytes==0 ){
+    sqlite3_free(pOld); /* IMP: R-26507-47431 */
+    return 0;
+  }
+  if( nBytes>=0x7fffff00 ){
+    /* The 0x7ffff00 limit term is explained in comments on sqlite3Malloc() */
+    return 0;
+  }
+  nOld = sqlite3MallocSize(pOld);
+  /* IMPLEMENTATION-OF: R-46199-30249 SQLite guarantees that the second
+  ** argument to xRealloc is always a value returned by a prior call to
+  ** xRoundup. */
+  nNew = sqlite3GlobalConfig.m.xRoundup((int)nBytes);
+  if( nOld==nNew ){
+    pNew = pOld;
+  }else if( sqlite3GlobalConfig.bMemstat ){
+    sqlite3_int64 nUsed;
+    sqlite3_mutex_enter(mem0.mutex);
+    sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, (int)nBytes);
+    nDiff = nNew - nOld;
+    if( nDiff>0 && (nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED)) >=
+          mem0.alarmThreshold-nDiff ){
+      sqlite3MallocAlarm(nDiff);
+      if( mem0.hardLimit>0 && nUsed >= mem0.hardLimit - nDiff ){
+        sqlite3_mutex_leave(mem0.mutex);
+        test_oom_breakpoint(1);
+        return 0;
+      }
+    }
+    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+    if( pNew==0 && mem0.alarmThreshold>0 ){
+      sqlite3MallocAlarm((int)nBytes);
+      pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
+    }
+#endif
+    if( pNew ){
+      nNew = sqlite3MallocSize(pNew);
+      sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nNew-nOld);
+    }
+    sqlite3_mutex_leave(mem0.mutex);
+  }else{
+    pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
+  }
+  assert( EIGHT_BYTE_ALIGNMENT(pNew) ); /* IMP: R-11148-40995 */
+  return pNew;
+}
+
+/*
+** The public interface to sqlite3Realloc.  Make sure that the memory
+** subsystem is initialized prior to invoking sqliteRealloc.
+*/
+SQLITE_API void *sqlite3_realloc(void *pOld, int n){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  if( n<0 ) n = 0;  /* IMP: R-26507-47431 */
+  return sqlite3Realloc(pOld, n);
+}
+SQLITE_API void *sqlite3_realloc64(void *pOld, sqlite3_uint64 n){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return sqlite3Realloc(pOld, n);
+}
+
+
+/*
+** Allocate and zero memory.
+*/
+SQLITE_PRIVATE void *sqlite3MallocZero(u64 n){
+  void *p = sqlite3Malloc(n);
+  if( p ){
+    memset(p, 0, (size_t)n);
+  }
+  return p;
+}
+
+/*
+** Allocate and zero memory.  If the allocation fails, make
+** the mallocFailed flag in the connection pointer.
+*/
+SQLITE_PRIVATE void *sqlite3DbMallocZero(sqlite3 *db, u64 n){
+  void *p;
+  testcase( db==0 );
+  p = sqlite3DbMallocRaw(db, n);
+  if( p ) memset(p, 0, (size_t)n);
+  return p;
+}
+
+
+/* Finish the work of sqlite3DbMallocRawNN for the unusual and
+** slower case when the allocation cannot be fulfilled using lookaside.
+*/
+static SQLITE_NOINLINE void *dbMallocRawFinish(sqlite3 *db, u64 n){
+  void *p;
+  assert( db!=0 );
+  p = sqlite3Malloc(n);
+  if( !p ) sqlite3OomFault(db);
+  sqlite3MemdebugSetType(p,
+         (db->lookaside.bDisable==0) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP);
+  return p;
+}
+
+/*
+** Allocate memory, either lookaside (if possible) or heap.
+** If the allocation fails, set the mallocFailed flag in
+** the connection pointer.
+**
+** If db!=0 and db->mallocFailed is true (indicating a prior malloc
+** failure on the same database connection) then always return 0.
+** Hence for a particular database connection, once malloc starts
+** failing, it fails consistently until mallocFailed is reset.
+** This is an important assumption.  There are many places in the
+** code that do things like this:
+**
+**         int *a = (int*)sqlite3DbMallocRaw(db, 100);
+**         int *b = (int*)sqlite3DbMallocRaw(db, 200);
+**         if( b ) a[10] = 9;
+**
+** In other words, if a subsequent malloc (ex: "b") worked, it is assumed
+** that all prior mallocs (ex: "a") worked too.
+**
+** The sqlite3MallocRawNN() variant guarantees that the "db" parameter is
+** not a NULL pointer.
+*/
+SQLITE_PRIVATE void *sqlite3DbMallocRaw(sqlite3 *db, u64 n){
+  void *p;
+  if( db ) return sqlite3DbMallocRawNN(db, n);
+  p = sqlite3Malloc(n);
+  sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+  return p;
+}
+SQLITE_PRIVATE void *sqlite3DbMallocRawNN(sqlite3 *db, u64 n){
+#ifndef SQLITE_OMIT_LOOKASIDE
+  LookasideSlot *pBuf;
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( db->pnBytesFreed==0 );
+  if( n>db->lookaside.sz ){
+    if( !db->lookaside.bDisable ){
+      db->lookaside.anStat[1]++;
+    }else if( db->mallocFailed ){
+      return 0;
+    }
+    return dbMallocRawFinish(db, n);
+  }
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  if( n<=LOOKASIDE_SMALL ){
+    if( (pBuf = db->lookaside.pSmallFree)!=0 ){
+      db->lookaside.pSmallFree = pBuf->pNext;
+      db->lookaside.anStat[0]++;
+      return (void*)pBuf;
+    }else if( (pBuf = db->lookaside.pSmallInit)!=0 ){
+      db->lookaside.pSmallInit = pBuf->pNext;
+      db->lookaside.anStat[0]++;
+      return (void*)pBuf;
+    }
+  }
+#endif
+  if( (pBuf = db->lookaside.pFree)!=0 ){
+    db->lookaside.pFree = pBuf->pNext;
+    db->lookaside.anStat[0]++;
+    return (void*)pBuf;
+  }else if( (pBuf = db->lookaside.pInit)!=0 ){
+    db->lookaside.pInit = pBuf->pNext;
+    db->lookaside.anStat[0]++;
+    return (void*)pBuf;
+  }else{
+    db->lookaside.anStat[2]++;
+  }
+#else
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( db->pnBytesFreed==0 );
+  if( db->mallocFailed ){
+    return 0;
+  }
+#endif
+  return dbMallocRawFinish(db, n);
+}
+
+/* Forward declaration */
+static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n);
+
+/*
+** Resize the block of memory pointed to by p to n bytes. If the
+** resize fails, set the mallocFailed flag in the connection object.
+*/
+SQLITE_PRIVATE void *sqlite3DbRealloc(sqlite3 *db, void *p, u64 n){
+  assert( db!=0 );
+  if( p==0 ) return sqlite3DbMallocRawNN(db, n);
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( ((uptr)p)<(uptr)db->lookaside.pEnd ){
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+    if( ((uptr)p)>=(uptr)db->lookaside.pMiddle ){
+      if( n<=LOOKASIDE_SMALL ) return p;
+    }else
+#endif
+    if( ((uptr)p)>=(uptr)db->lookaside.pStart ){
+      if( n<=db->lookaside.szTrue ) return p;
+    }
+  }
+  return dbReallocFinish(db, p, n);
+}
+static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n){
+  void *pNew = 0;
+  assert( db!=0 );
+  assert( p!=0 );
+  if( db->mallocFailed==0 ){
+    if( isLookaside(db, p) ){
+      pNew = sqlite3DbMallocRawNN(db, n);
+      if( pNew ){
+        memcpy(pNew, p, lookasideMallocSize(db, p));
+        sqlite3DbFree(db, p);
+      }
+    }else{
+      assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+      assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
+      sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+      pNew = sqlite3Realloc(p, n);
+      if( !pNew ){
+        sqlite3OomFault(db);
+      }
+      sqlite3MemdebugSetType(pNew,
+            (db->lookaside.bDisable==0 ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
+    }
+  }
+  return pNew;
+}
+
+/*
+** Attempt to reallocate p.  If the reallocation fails, then free p
+** and set the mallocFailed flag in the database connection.
+*/
+SQLITE_PRIVATE void *sqlite3DbReallocOrFree(sqlite3 *db, void *p, u64 n){
+  void *pNew;
+  pNew = sqlite3DbRealloc(db, p, n);
+  if( !pNew ){
+    sqlite3DbFree(db, p);
+  }
+  return pNew;
+}
+
+/*
+** Make a copy of a string in memory obtained from sqliteMalloc(). These
+** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This
+** is because when memory debugging is turned on, these two functions are
+** called via macros that record the current file and line number in the
+** ThreadData structure.
+*/
+SQLITE_PRIVATE char *sqlite3DbStrDup(sqlite3 *db, const char *z){
+  char *zNew;
+  size_t n;
+  if( z==0 ){
+    return 0;
+  }
+  n = strlen(z) + 1;
+  zNew = sqlite3DbMallocRaw(db, n);
+  if( zNew ){
+    memcpy(zNew, z, n);
+  }
+  return zNew;
+}
+SQLITE_PRIVATE char *sqlite3DbStrNDup(sqlite3 *db, const char *z, u64 n){
+  char *zNew;
+  assert( db!=0 );
+  assert( z!=0 || n==0 );
+  assert( (n&0x7fffffff)==n );
+  zNew = z ? sqlite3DbMallocRawNN(db, n+1) : 0;
+  if( zNew ){
+    memcpy(zNew, z, (size_t)n);
+    zNew[n] = 0;
+  }
+  return zNew;
+}
+
+/*
+** The text between zStart and zEnd represents a phrase within a larger
+** SQL statement.  Make a copy of this phrase in space obtained form
+** sqlite3DbMalloc().  Omit leading and trailing whitespace.
+*/
+SQLITE_PRIVATE char *sqlite3DbSpanDup(sqlite3 *db, const char *zStart, const char *zEnd){
+  int n;
+#ifdef SQLITE_DEBUG
+  /* Because of the way the parser works, the span is guaranteed to contain
+  ** at least one non-space character */
+  for(n=0; sqlite3Isspace(zStart[n]); n++){ assert( &zStart[n]<zEnd ); }
+#endif
+  while( sqlite3Isspace(zStart[0]) ) zStart++;
+  n = (int)(zEnd - zStart);
+  while( sqlite3Isspace(zStart[n-1]) ) n--;
+  return sqlite3DbStrNDup(db, zStart, n);
+}
+
+/*
+** Free any prior content in *pz and replace it with a copy of zNew.
+*/
+SQLITE_PRIVATE void sqlite3SetString(char **pz, sqlite3 *db, const char *zNew){
+  char *z = sqlite3DbStrDup(db, zNew);
+  sqlite3DbFree(db, *pz);
+  *pz = z;
+}
+
+/*
+** Call this routine to record the fact that an OOM (out-of-memory) error
+** has happened.  This routine will set db->mallocFailed, and also
+** temporarily disable the lookaside memory allocator and interrupt
+** any running VDBEs.
+**
+** Always return a NULL pointer so that this routine can be invoked using
+**
+**      return sqlite3OomFault(db);
+**
+** and thereby avoid unnecessary stack frame allocations for the overwhelmingly
+** common case where no OOM occurs.
+*/
+SQLITE_PRIVATE void *sqlite3OomFault(sqlite3 *db){
+  if( db->mallocFailed==0 && db->bBenignMalloc==0 ){
+    db->mallocFailed = 1;
+    if( db->nVdbeExec>0 ){
+      AtomicStore(&db->u1.isInterrupted, 1);
+    }
+    DisableLookaside;
+    if( db->pParse ){
+      Parse *pParse;
+      sqlite3ErrorMsg(db->pParse, "out of memory");
+      db->pParse->rc = SQLITE_NOMEM_BKPT;
+      for(pParse=db->pParse->pOuterParse; pParse; pParse = pParse->pOuterParse){
+        pParse->nErr++;
+        pParse->rc = SQLITE_NOMEM;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** This routine reactivates the memory allocator and clears the
+** db->mallocFailed flag as necessary.
+**
+** The memory allocator is not restarted if there are running
+** VDBEs.
+*/
+SQLITE_PRIVATE void sqlite3OomClear(sqlite3 *db){
+  if( db->mallocFailed && db->nVdbeExec==0 ){
+    db->mallocFailed = 0;
+    AtomicStore(&db->u1.isInterrupted, 0);
+    assert( db->lookaside.bDisable>0 );
+    EnableLookaside;
+  }
+}
+
+/*
+** Take actions at the end of an API call to deal with error codes.
+*/
+static SQLITE_NOINLINE int apiHandleError(sqlite3 *db, int rc){
+  if( db->mallocFailed || rc==SQLITE_IOERR_NOMEM ){
+    sqlite3OomClear(db);
+    sqlite3Error(db, SQLITE_NOMEM);
+    return SQLITE_NOMEM_BKPT;
+  }
+  return rc & db->errMask;
+}
+
+/*
+** This function must be called before exiting any API function (i.e.
+** returning control to the user) that has called sqlite3_malloc or
+** sqlite3_realloc.
+**
+** The returned value is normally a copy of the second argument to this
+** function. However, if a malloc() failure has occurred since the previous
+** invocation SQLITE_NOMEM is returned instead.
+**
+** If an OOM as occurred, then the connection error-code (the value
+** returned by sqlite3_errcode()) is set to SQLITE_NOMEM.
+*/
+SQLITE_PRIVATE int sqlite3ApiExit(sqlite3* db, int rc){
+  /* If the db handle must hold the connection handle mutex here.
+  ** Otherwise the read (and possible write) of db->mallocFailed
+  ** is unsafe, as is the call to sqlite3Error().
+  */
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( db->mallocFailed || rc ){
+    return apiHandleError(db, rc);
+  }
+  return 0;
+}
+
+/************** End of malloc.c **********************************************/
+/************** Begin file printf.c ******************************************/
+/*
+** The "printf" code that follows dates from the 1980's.  It is in
+** the public domain.
+**
+**************************************************************************
+**
+** This file contains code for a set of "printf"-like routines.  These
+** routines format strings much like the printf() from the standard C
+** library, though the implementation here has enhancements to support
+** SQLite.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** Conversion types fall into various categories as defined by the
+** following enumeration.
+*/
+#define etRADIX       0 /* non-decimal integer types.  %x %o */
+#define etFLOAT       1 /* Floating point.  %f */
+#define etEXP         2 /* Exponentional notation. %e and %E */
+#define etGENERIC     3 /* Floating or exponential, depending on exponent. %g */
+#define etSIZE        4 /* Return number of characters processed so far. %n */
+#define etSTRING      5 /* Strings. %s */
+#define etDYNSTRING   6 /* Dynamically allocated strings. %z */
+#define etPERCENT     7 /* Percent symbol. %% */
+#define etCHARX       8 /* Characters. %c */
+/* The rest are extensions, not normally found in printf() */
+#define etSQLESCAPE   9 /* Strings with '\'' doubled.  %q */
+#define etSQLESCAPE2 10 /* Strings with '\'' doubled and enclosed in '',
+                          NULL pointers replaced by SQL NULL.  %Q */
+#define etTOKEN      11 /* a pointer to a Token structure */
+#define etSRCITEM    12 /* a pointer to a SrcItem */
+#define etPOINTER    13 /* The %p conversion */
+#define etSQLESCAPE3 14 /* %w -> Strings with '\"' doubled */
+#define etORDINAL    15 /* %r -> 1st, 2nd, 3rd, 4th, etc.  English only */
+#define etDECIMAL    16 /* %d or %u, but not %x, %o */
+
+#define etINVALID    17 /* Any unrecognized conversion type */
+
+
+/*
+** An "etByte" is an 8-bit unsigned value.
+*/
+typedef unsigned char etByte;
+
+/*
+** Each builtin conversion character (ex: the 'd' in "%d") is described
+** by an instance of the following structure
+*/
+typedef struct et_info {   /* Information about each format field */
+  char fmttype;            /* The format field code letter */
+  etByte base;             /* The base for radix conversion */
+  etByte flags;            /* One or more of FLAG_ constants below */
+  etByte type;             /* Conversion paradigm */
+  etByte charset;          /* Offset into aDigits[] of the digits string */
+  etByte prefix;           /* Offset into aPrefix[] of the prefix string */
+} et_info;
+
+/*
+** Allowed values for et_info.flags
+*/
+#define FLAG_SIGNED    1     /* True if the value to convert is signed */
+#define FLAG_STRING    4     /* Allow infinite precision */
+
+
+/*
+** The following table is searched linearly, so it is good to put the
+** most frequently used conversion types first.
+*/
+static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
+static const char aPrefix[] = "-x0\000X0";
+static const et_info fmtinfo[] = {
+  {  'd', 10, 1, etDECIMAL,    0,  0 },
+  {  's',  0, 4, etSTRING,     0,  0 },
+  {  'g',  0, 1, etGENERIC,    30, 0 },
+  {  'z',  0, 4, etDYNSTRING,  0,  0 },
+  {  'q',  0, 4, etSQLESCAPE,  0,  0 },
+  {  'Q',  0, 4, etSQLESCAPE2, 0,  0 },
+  {  'w',  0, 4, etSQLESCAPE3, 0,  0 },
+  {  'c',  0, 0, etCHARX,      0,  0 },
+  {  'o',  8, 0, etRADIX,      0,  2 },
+  {  'u', 10, 0, etDECIMAL,    0,  0 },
+  {  'x', 16, 0, etRADIX,      16, 1 },
+  {  'X', 16, 0, etRADIX,      0,  4 },
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  {  'f',  0, 1, etFLOAT,      0,  0 },
+  {  'e',  0, 1, etEXP,        30, 0 },
+  {  'E',  0, 1, etEXP,        14, 0 },
+  {  'G',  0, 1, etGENERIC,    14, 0 },
+#endif
+  {  'i', 10, 1, etDECIMAL,    0,  0 },
+  {  'n',  0, 0, etSIZE,       0,  0 },
+  {  '%',  0, 0, etPERCENT,    0,  0 },
+  {  'p', 16, 0, etPOINTER,    0,  1 },
+
+  /* All the rest are undocumented and are for internal use only */
+  {  'T',  0, 0, etTOKEN,      0,  0 },
+  {  'S',  0, 0, etSRCITEM,    0,  0 },
+  {  'r', 10, 1, etORDINAL,    0,  0 },
+};
+
+/* Notes:
+**
+**    %S    Takes a pointer to SrcItem.  Shows name or database.name
+**    %!S   Like %S but prefer the zName over the zAlias
+*/
+
+/*
+** Set the StrAccum object to an error mode.
+*/
+SQLITE_PRIVATE void sqlite3StrAccumSetError(StrAccum *p, u8 eError){
+  assert( eError==SQLITE_NOMEM || eError==SQLITE_TOOBIG );
+  p->accError = eError;
+  if( p->mxAlloc ) sqlite3_str_reset(p);
+  if( eError==SQLITE_TOOBIG ) sqlite3ErrorToParser(p->db, eError);
+}
+
+/*
+** Extra argument values from a PrintfArguments object
+*/
+static sqlite3_int64 getIntArg(PrintfArguments *p){
+  if( p->nArg<=p->nUsed ) return 0;
+  return sqlite3_value_int64(p->apArg[p->nUsed++]);
+}
+static double getDoubleArg(PrintfArguments *p){
+  if( p->nArg<=p->nUsed ) return 0.0;
+  return sqlite3_value_double(p->apArg[p->nUsed++]);
+}
+static char *getTextArg(PrintfArguments *p){
+  if( p->nArg<=p->nUsed ) return 0;
+  return (char*)sqlite3_value_text(p->apArg[p->nUsed++]);
+}
+
+/*
+** Allocate memory for a temporary buffer needed for printf rendering.
+**
+** If the requested size of the temp buffer is larger than the size
+** of the output buffer in pAccum, then cause an SQLITE_TOOBIG error.
+** Do the size check before the memory allocation to prevent rogue
+** SQL from requesting large allocations using the precision or width
+** field of the printf() function.
+*/
+static char *printfTempBuf(sqlite3_str *pAccum, sqlite3_int64 n){
+  char *z;
+  if( pAccum->accError ) return 0;
+  if( n>pAccum->nAlloc && n>pAccum->mxAlloc ){
+    sqlite3StrAccumSetError(pAccum, SQLITE_TOOBIG);
+    return 0;
+  }
+  z = sqlite3DbMallocRaw(pAccum->db, n);
+  if( z==0 ){
+    sqlite3StrAccumSetError(pAccum, SQLITE_NOMEM);
+  }
+  return z;
+}
+
+/*
+** On machines with a small stack size, you can redefine the
+** SQLITE_PRINT_BUF_SIZE to be something smaller, if desired.
+*/
+#ifndef SQLITE_PRINT_BUF_SIZE
+# define SQLITE_PRINT_BUF_SIZE 70
+#endif
+#define etBUFSIZE SQLITE_PRINT_BUF_SIZE  /* Size of the output buffer */
+
+/*
+** Hard limit on the precision of floating-point conversions.
+*/
+#ifndef SQLITE_PRINTF_PRECISION_LIMIT
+# define SQLITE_FP_PRECISION_LIMIT 100000000
+#endif
+
+/*
+** Render a string given by "fmt" into the StrAccum object.
+*/
+SQLITE_API void sqlite3_str_vappendf(
+  sqlite3_str *pAccum,       /* Accumulate results here */
+  const char *fmt,           /* Format string */
+  va_list ap                 /* arguments */
+){
+  int c;                     /* Next character in the format string */
+  char *bufpt;               /* Pointer to the conversion buffer */
+  int precision;             /* Precision of the current field */
+  int length;                /* Length of the field */
+  int idx;                   /* A general purpose loop counter */
+  int width;                 /* Width of the current field */
+  etByte flag_leftjustify;   /* True if "-" flag is present */
+  etByte flag_prefix;        /* '+' or ' ' or 0 for prefix */
+  etByte flag_alternateform; /* True if "#" flag is present */
+  etByte flag_altform2;      /* True if "!" flag is present */
+  etByte flag_zeropad;       /* True if field width constant starts with zero */
+  etByte flag_long;          /* 1 for the "l" flag, 2 for "ll", 0 by default */
+  etByte done;               /* Loop termination flag */
+  etByte cThousand;          /* Thousands separator for %d and %u */
+  etByte xtype = etINVALID;  /* Conversion paradigm */
+  u8 bArgList;               /* True for SQLITE_PRINTF_SQLFUNC */
+  char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
+  sqlite_uint64 longvalue;   /* Value for integer types */
+  double realvalue;          /* Value for real types */
+  const et_info *infop;      /* Pointer to the appropriate info structure */
+  char *zOut;                /* Rendering buffer */
+  int nOut;                  /* Size of the rendering buffer */
+  char *zExtra = 0;          /* Malloced memory used by some conversion */
+  int exp, e2;               /* exponent of real numbers */
+  etByte flag_dp;            /* True if decimal point should be shown */
+  etByte flag_rtz;           /* True if trailing zeros should be removed */
+
+  PrintfArguments *pArgList = 0; /* Arguments for SQLITE_PRINTF_SQLFUNC */
+  char buf[etBUFSIZE];       /* Conversion buffer */
+
+  /* pAccum never starts out with an empty buffer that was obtained from
+  ** malloc().  This precondition is required by the mprintf("%z...")
+  ** optimization. */
+  assert( pAccum->nChar>0 || (pAccum->printfFlags&SQLITE_PRINTF_MALLOCED)==0 );
+
+  bufpt = 0;
+  if( (pAccum->printfFlags & SQLITE_PRINTF_SQLFUNC)!=0 ){
+    pArgList = va_arg(ap, PrintfArguments*);
+    bArgList = 1;
+  }else{
+    bArgList = 0;
+  }
+  for(; (c=(*fmt))!=0; ++fmt){
+    if( c!='%' ){
+      bufpt = (char *)fmt;
+#if HAVE_STRCHRNUL
+      fmt = strchrnul(fmt, '%');
+#else
+      do{ fmt++; }while( *fmt && *fmt != '%' );
+#endif
+      sqlite3_str_append(pAccum, bufpt, (int)(fmt - bufpt));
+      if( *fmt==0 ) break;
+    }
+    if( (c=(*++fmt))==0 ){
+      sqlite3_str_append(pAccum, "%", 1);
+      break;
+    }
+    /* Find out what flags are present */
+    flag_leftjustify = flag_prefix = cThousand =
+     flag_alternateform = flag_altform2 = flag_zeropad = 0;
+    done = 0;
+    width = 0;
+    flag_long = 0;
+    precision = -1;
+    do{
+      switch( c ){
+        case '-':   flag_leftjustify = 1;     break;
+        case '+':   flag_prefix = '+';        break;
+        case ' ':   flag_prefix = ' ';        break;
+        case '#':   flag_alternateform = 1;   break;
+        case '!':   flag_altform2 = 1;        break;
+        case '0':   flag_zeropad = 1;         break;
+        case ',':   cThousand = ',';          break;
+        default:    done = 1;                 break;
+        case 'l': {
+          flag_long = 1;
+          c = *++fmt;
+          if( c=='l' ){
+            c = *++fmt;
+            flag_long = 2;
+          }
+          done = 1;
+          break;
+        }
+        case '1': case '2': case '3': case '4': case '5':
+        case '6': case '7': case '8': case '9': {
+          unsigned wx = c - '0';
+          while( (c = *++fmt)>='0' && c<='9' ){
+            wx = wx*10 + c - '0';
+          }
+          testcase( wx>0x7fffffff );
+          width = wx & 0x7fffffff;
+#ifdef SQLITE_PRINTF_PRECISION_LIMIT
+          if( width>SQLITE_PRINTF_PRECISION_LIMIT ){
+            width = SQLITE_PRINTF_PRECISION_LIMIT;
+          }
+#endif
+          if( c!='.' && c!='l' ){
+            done = 1;
+          }else{
+            fmt--;
+          }
+          break;
+        }
+        case '*': {
+          if( bArgList ){
+            width = (int)getIntArg(pArgList);
+          }else{
+            width = va_arg(ap,int);
+          }
+          if( width<0 ){
+            flag_leftjustify = 1;
+            width = width >= -2147483647 ? -width : 0;
+          }
+#ifdef SQLITE_PRINTF_PRECISION_LIMIT
+          if( width>SQLITE_PRINTF_PRECISION_LIMIT ){
+            width = SQLITE_PRINTF_PRECISION_LIMIT;
+          }
+#endif
+          if( (c = fmt[1])!='.' && c!='l' ){
+            c = *++fmt;
+            done = 1;
+          }
+          break;
+        }
+        case '.': {
+          c = *++fmt;
+          if( c=='*' ){
+            if( bArgList ){
+              precision = (int)getIntArg(pArgList);
+            }else{
+              precision = va_arg(ap,int);
+            }
+            if( precision<0 ){
+              precision = precision >= -2147483647 ? -precision : -1;
+            }
+            c = *++fmt;
+          }else{
+            unsigned px = 0;
+            while( c>='0' && c<='9' ){
+              px = px*10 + c - '0';
+              c = *++fmt;
+            }
+            testcase( px>0x7fffffff );
+            precision = px & 0x7fffffff;
+          }
+#ifdef SQLITE_PRINTF_PRECISION_LIMIT
+          if( precision>SQLITE_PRINTF_PRECISION_LIMIT ){
+            precision = SQLITE_PRINTF_PRECISION_LIMIT;
+          }
+#endif
+          if( c=='l' ){
+            --fmt;
+          }else{
+            done = 1;
+          }
+          break;
+        }
+      }
+    }while( !done && (c=(*++fmt))!=0 );
+
+    /* Fetch the info entry for the field */
+    infop = &fmtinfo[0];
+    xtype = etINVALID;
+    for(idx=0; idx<ArraySize(fmtinfo); idx++){
+      if( c==fmtinfo[idx].fmttype ){
+        infop = &fmtinfo[idx];
+        xtype = infop->type;
+        break;
+      }
+    }
+
+    /*
+    ** At this point, variables are initialized as follows:
+    **
+    **   flag_alternateform          TRUE if a '#' is present.
+    **   flag_altform2               TRUE if a '!' is present.
+    **   flag_prefix                 '+' or ' ' or zero
+    **   flag_leftjustify            TRUE if a '-' is present or if the
+    **                               field width was negative.
+    **   flag_zeropad                TRUE if the width began with 0.
+    **   flag_long                   1 for "l", 2 for "ll"
+    **   width                       The specified field width.  This is
+    **                               always non-negative.  Zero is the default.
+    **   precision                   The specified precision.  The default
+    **                               is -1.
+    **   xtype                       The class of the conversion.
+    **   infop                       Pointer to the appropriate info struct.
+    */
+    assert( width>=0 );
+    assert( precision>=(-1) );
+    switch( xtype ){
+      case etPOINTER:
+        flag_long = sizeof(char*)==sizeof(i64) ? 2 :
+                     sizeof(char*)==sizeof(long int) ? 1 : 0;
+        /* no break */ deliberate_fall_through
+      case etORDINAL:
+      case etRADIX:
+        cThousand = 0;
+        /* no break */ deliberate_fall_through
+      case etDECIMAL:
+        if( infop->flags & FLAG_SIGNED ){
+          i64 v;
+          if( bArgList ){
+            v = getIntArg(pArgList);
+          }else if( flag_long ){
+            if( flag_long==2 ){
+              v = va_arg(ap,i64) ;
+            }else{
+              v = va_arg(ap,long int);
+            }
+          }else{
+            v = va_arg(ap,int);
+          }
+          if( v<0 ){
+            testcase( v==SMALLEST_INT64 );
+            testcase( v==(-1) );
+            longvalue = ~v;
+            longvalue++;
+            prefix = '-';
+          }else{
+            longvalue = v;
+            prefix = flag_prefix;
+          }
+        }else{
+          if( bArgList ){
+            longvalue = (u64)getIntArg(pArgList);
+          }else if( flag_long ){
+            if( flag_long==2 ){
+              longvalue = va_arg(ap,u64);
+            }else{
+              longvalue = va_arg(ap,unsigned long int);
+            }
+          }else{
+            longvalue = va_arg(ap,unsigned int);
+          }
+          prefix = 0;
+        }
+        if( longvalue==0 ) flag_alternateform = 0;
+        if( flag_zeropad && precision<width-(prefix!=0) ){
+          precision = width-(prefix!=0);
+        }
+        if( precision<etBUFSIZE-10-etBUFSIZE/3 ){
+          nOut = etBUFSIZE;
+          zOut = buf;
+        }else{
+          u64 n;
+          n = (u64)precision + 10;
+          if( cThousand ) n += precision/3;
+          zOut = zExtra = printfTempBuf(pAccum, n);
+          if( zOut==0 ) return;
+          nOut = (int)n;
+        }
+        bufpt = &zOut[nOut-1];
+        if( xtype==etORDINAL ){
+          static const char zOrd[] = "thstndrd";
+          int x = (int)(longvalue % 10);
+          if( x>=4 || (longvalue/10)%10==1 ){
+            x = 0;
+          }
+          *(--bufpt) = zOrd[x*2+1];
+          *(--bufpt) = zOrd[x*2];
+        }
+        {
+          const char *cset = &aDigits[infop->charset];
+          u8 base = infop->base;
+          do{                                           /* Convert to ascii */
+            *(--bufpt) = cset[longvalue%base];
+            longvalue = longvalue/base;
+          }while( longvalue>0 );
+        }
+        length = (int)(&zOut[nOut-1]-bufpt);
+        while( precision>length ){
+          *(--bufpt) = '0';                             /* Zero pad */
+          length++;
+        }
+        if( cThousand ){
+          int nn = (length - 1)/3;  /* Number of "," to insert */
+          int ix = (length - 1)%3 + 1;
+          bufpt -= nn;
+          for(idx=0; nn>0; idx++){
+            bufpt[idx] = bufpt[idx+nn];
+            ix--;
+            if( ix==0 ){
+              bufpt[++idx] = cThousand;
+              nn--;
+              ix = 3;
+            }
+          }
+        }
+        if( prefix ) *(--bufpt) = prefix;               /* Add sign */
+        if( flag_alternateform && infop->prefix ){      /* Add "0" or "0x" */
+          const char *pre;
+          char x;
+          pre = &aPrefix[infop->prefix];
+          for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
+        }
+        length = (int)(&zOut[nOut-1]-bufpt);
+        break;
+      case etFLOAT:
+      case etEXP:
+      case etGENERIC: {
+        FpDecode s;
+        int iRound;
+        int j;
+
+        if( bArgList ){
+          realvalue = getDoubleArg(pArgList);
+        }else{
+          realvalue = va_arg(ap,double);
+        }
+        if( precision<0 ) precision = 6;         /* Set default precision */
+#ifdef SQLITE_FP_PRECISION_LIMIT
+        if( precision>SQLITE_FP_PRECISION_LIMIT ){
+          precision = SQLITE_FP_PRECISION_LIMIT;
+        }
+#endif
+        if( xtype==etFLOAT ){
+          iRound = -precision;
+        }else if( xtype==etGENERIC ){
+          if( precision==0 ) precision = 1;
+          iRound = precision;
+        }else{
+          iRound = precision+1;
+        }
+        sqlite3FpDecode(&s, realvalue, iRound, flag_altform2 ? 26 : 16);
+        if( s.isSpecial ){
+          if( s.isSpecial==2 ){
+            bufpt = flag_zeropad ? "null" : "NaN";
+            length = sqlite3Strlen30(bufpt);
+            break;
+          }else if( flag_zeropad ){
+            s.z[0] = '9';
+            s.iDP = 1000;
+            s.n = 1;
+          }else{
+            memcpy(buf, "-Inf", 5);
+            bufpt = buf;
+            if( s.sign=='-' ){
+              /* no-op */
+            }else if( flag_prefix ){
+              buf[0] = flag_prefix;
+            }else{
+              bufpt++;
+            }
+            length = sqlite3Strlen30(bufpt);
+            break;
+          }
+        }
+        if( s.sign=='-' ){
+          prefix = '-';
+        }else{
+          prefix = flag_prefix;
+        }
+
+        exp = s.iDP-1;
+
+        /*
+        ** If the field type is etGENERIC, then convert to either etEXP
+        ** or etFLOAT, as appropriate.
+        */
+        if( xtype==etGENERIC ){
+          assert( precision>0 );
+          precision--;
+          flag_rtz = !flag_alternateform;
+          if( exp<-4 || exp>precision ){
+            xtype = etEXP;
+          }else{
+            precision = precision - exp;
+            xtype = etFLOAT;
+          }
+        }else{
+          flag_rtz = flag_altform2;
+        }
+        if( xtype==etEXP ){
+          e2 = 0;
+        }else{
+          e2 = s.iDP - 1;
+        }
+        bufpt = buf;
+        {
+          i64 szBufNeeded;           /* Size of a temporary buffer needed */
+          szBufNeeded = MAX(e2,0)+(i64)precision+(i64)width+15;
+          if( cThousand && e2>0 ) szBufNeeded += (e2+2)/3;
+          if( szBufNeeded > etBUFSIZE ){
+            bufpt = zExtra = printfTempBuf(pAccum, szBufNeeded);
+            if( bufpt==0 ) return;
+          }
+        }
+        zOut = bufpt;
+        flag_dp = (precision>0 ?1:0) | flag_alternateform | flag_altform2;
+        /* The sign in front of the number */
+        if( prefix ){
+          *(bufpt++) = prefix;
+        }
+        /* Digits prior to the decimal point */
+        j = 0;
+        if( e2<0 ){
+          *(bufpt++) = '0';
+        }else{
+          for(; e2>=0; e2--){
+            *(bufpt++) = j<s.n ? s.z[j++] : '0';
+            if( cThousand && (e2%3)==0 && e2>1 ) *(bufpt++) = ',';
+          }
+        }
+        /* The decimal point */
+        if( flag_dp ){
+          *(bufpt++) = '.';
+        }
+        /* "0" digits after the decimal point but before the first
+        ** significant digit of the number */
+        for(e2++; e2<0 && precision>0; precision--, e2++){
+          *(bufpt++) = '0';
+        }
+        /* Significant digits after the decimal point */
+        while( (precision--)>0 ){
+          *(bufpt++) = j<s.n ? s.z[j++] : '0';
+        }
+        /* Remove trailing zeros and the "." if no digits follow the "." */
+        if( flag_rtz && flag_dp ){
+          while( bufpt[-1]=='0' ) *(--bufpt) = 0;
+          assert( bufpt>zOut );
+          if( bufpt[-1]=='.' ){
+            if( flag_altform2 ){
+              *(bufpt++) = '0';
+            }else{
+              *(--bufpt) = 0;
+            }
+          }
+        }
+        /* Add the "eNNN" suffix */
+        if( xtype==etEXP ){
+          exp = s.iDP - 1;
+          *(bufpt++) = aDigits[infop->charset];
+          if( exp<0 ){
+            *(bufpt++) = '-'; exp = -exp;
+          }else{
+            *(bufpt++) = '+';
+          }
+          if( exp>=100 ){
+            *(bufpt++) = (char)((exp/100)+'0');        /* 100's digit */
+            exp %= 100;
+          }
+          *(bufpt++) = (char)(exp/10+'0');             /* 10's digit */
+          *(bufpt++) = (char)(exp%10+'0');             /* 1's digit */
+        }
+        *bufpt = 0;
+
+        /* The converted number is in buf[] and zero terminated. Output it.
+        ** Note that the number is in the usual order, not reversed as with
+        ** integer conversions. */
+        length = (int)(bufpt-zOut);
+        bufpt = zOut;
+
+        /* Special case:  Add leading zeros if the flag_zeropad flag is
+        ** set and we are not left justified */
+        if( flag_zeropad && !flag_leftjustify && length < width){
+          int i;
+          int nPad = width - length;
+          for(i=width; i>=nPad; i--){
+            bufpt[i] = bufpt[i-nPad];
+          }
+          i = prefix!=0;
+          while( nPad-- ) bufpt[i++] = '0';
+          length = width;
+        }
+        break;
+      }
+      case etSIZE:
+        if( !bArgList ){
+          *(va_arg(ap,int*)) = pAccum->nChar;
+        }
+        length = width = 0;
+        break;
+      case etPERCENT:
+        buf[0] = '%';
+        bufpt = buf;
+        length = 1;
+        break;
+      case etCHARX:
+        if( bArgList ){
+          bufpt = getTextArg(pArgList);
+          length = 1;
+          if( bufpt ){
+            buf[0] = c = *(bufpt++);
+            if( (c&0xc0)==0xc0 ){
+              while( length<4 && (bufpt[0]&0xc0)==0x80 ){
+                buf[length++] = *(bufpt++);
+              }
+            }
+          }else{
+            buf[0] = 0;
+          }
+        }else{
+          unsigned int ch = va_arg(ap,unsigned int);
+          if( ch<0x00080 ){
+            buf[0] = ch & 0xff;
+            length = 1;
+          }else if( ch<0x00800 ){
+            buf[0] = 0xc0 + (u8)((ch>>6)&0x1f);
+            buf[1] = 0x80 + (u8)(ch & 0x3f);
+            length = 2;
+          }else if( ch<0x10000 ){
+            buf[0] = 0xe0 + (u8)((ch>>12)&0x0f);
+            buf[1] = 0x80 + (u8)((ch>>6) & 0x3f);
+            buf[2] = 0x80 + (u8)(ch & 0x3f);
+            length = 3;
+          }else{
+            buf[0] = 0xf0 + (u8)((ch>>18) & 0x07);
+            buf[1] = 0x80 + (u8)((ch>>12) & 0x3f);
+            buf[2] = 0x80 + (u8)((ch>>6) & 0x3f);
+            buf[3] = 0x80 + (u8)(ch & 0x3f);
+            length = 4;
+          }
+        }
+        if( precision>1 ){
+          i64 nPrior = 1;
+          width -= precision-1;
+          if( width>1 && !flag_leftjustify ){
+            sqlite3_str_appendchar(pAccum, width-1, ' ');
+            width = 0;
+          }
+          sqlite3_str_append(pAccum, buf, length);
+          precision--;
+          while( precision > 1 ){
+            i64 nCopyBytes;
+            if( nPrior > precision-1 ) nPrior = precision - 1;
+            nCopyBytes = length*nPrior;
+            if( nCopyBytes + pAccum->nChar >= pAccum->nAlloc ){
+              sqlite3StrAccumEnlarge(pAccum, nCopyBytes);
+            }
+            if( pAccum->accError ) break;
+            sqlite3_str_append(pAccum,
+                 &pAccum->zText[pAccum->nChar-nCopyBytes], nCopyBytes);
+            precision -= nPrior;
+            nPrior *= 2;
+          }
+        }
+        bufpt = buf;
+        flag_altform2 = 1;
+        goto adjust_width_for_utf8;
+      case etSTRING:
+      case etDYNSTRING:
+        if( bArgList ){
+          bufpt = getTextArg(pArgList);
+          xtype = etSTRING;
+        }else{
+          bufpt = va_arg(ap,char*);
+        }
+        if( bufpt==0 ){
+          bufpt = "";
+        }else if( xtype==etDYNSTRING ){
+          if( pAccum->nChar==0
+           && pAccum->mxAlloc
+           && width==0
+           && precision<0
+           && pAccum->accError==0
+          ){
+            /* Special optimization for sqlite3_mprintf("%z..."):
+            ** Extend an existing memory allocation rather than creating
+            ** a new one. */
+            assert( (pAccum->printfFlags&SQLITE_PRINTF_MALLOCED)==0 );
+            pAccum->zText = bufpt;
+            pAccum->nAlloc = sqlite3DbMallocSize(pAccum->db, bufpt);
+            pAccum->nChar = 0x7fffffff & (int)strlen(bufpt);
+            pAccum->printfFlags |= SQLITE_PRINTF_MALLOCED;
+            length = 0;
+            break;
+          }
+          zExtra = bufpt;
+        }
+        if( precision>=0 ){
+          if( flag_altform2 ){
+            /* Set length to the number of bytes needed in order to display
+            ** precision characters */
+            unsigned char *z = (unsigned char*)bufpt;
+            while( precision-- > 0 && z[0] ){
+              SQLITE_SKIP_UTF8(z);
+            }
+            length = (int)(z - (unsigned char*)bufpt);
+          }else{
+            for(length=0; length<precision && bufpt[length]; length++){}
+          }
+        }else{
+          length = 0x7fffffff & (int)strlen(bufpt);
+        }
+      adjust_width_for_utf8:
+        if( flag_altform2 && width>0 ){
+          /* Adjust width to account for extra bytes in UTF-8 characters */
+          int ii = length - 1;
+          while( ii>=0 ) if( (bufpt[ii--] & 0xc0)==0x80 ) width++;
+        }
+        break;
+      case etSQLESCAPE:           /* %q: Escape ' characters */
+      case etSQLESCAPE2:          /* %Q: Escape ' and enclose in '...' */
+      case etSQLESCAPE3: {        /* %w: Escape " characters */
+        i64 i, j, k, n;
+        int needQuote, isnull;
+        char ch;
+        char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
+        char *escarg;
+
+        if( bArgList ){
+          escarg = getTextArg(pArgList);
+        }else{
+          escarg = va_arg(ap,char*);
+        }
+        isnull = escarg==0;
+        if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
+        /* For %q, %Q, and %w, the precision is the number of bytes (or
+        ** characters if the ! flags is present) to use from the input.
+        ** Because of the extra quoting characters inserted, the number
+        ** of output characters may be larger than the precision.
+        */
+        k = precision;
+        for(i=n=0; k!=0 && (ch=escarg[i])!=0; i++, k--){
+          if( ch==q )  n++;
+          if( flag_altform2 && (ch&0xc0)==0xc0 ){
+            while( (escarg[i+1]&0xc0)==0x80 ){ i++; }
+          }
+        }
+        needQuote = !isnull && xtype==etSQLESCAPE2;
+        n += i + 3;
+        if( n>etBUFSIZE ){
+          bufpt = zExtra = printfTempBuf(pAccum, n);
+          if( bufpt==0 ) return;
+        }else{
+          bufpt = buf;
+        }
+        j = 0;
+        if( needQuote ) bufpt[j++] = q;
+        k = i;
+        for(i=0; i<k; i++){
+          bufpt[j++] = ch = escarg[i];
+          if( ch==q ) bufpt[j++] = ch;
+        }
+        if( needQuote ) bufpt[j++] = q;
+        bufpt[j] = 0;
+        length = j;
+        goto adjust_width_for_utf8;
+      }
+      case etTOKEN: {
+        if( (pAccum->printfFlags & SQLITE_PRINTF_INTERNAL)==0 ) return;
+        if( flag_alternateform ){
+          /* %#T means an Expr pointer that uses Expr.u.zToken */
+          Expr *pExpr = va_arg(ap,Expr*);
+          if( ALWAYS(pExpr) && ALWAYS(!ExprHasProperty(pExpr,EP_IntValue)) ){
+            sqlite3_str_appendall(pAccum, (const char*)pExpr->u.zToken);
+            sqlite3RecordErrorOffsetOfExpr(pAccum->db, pExpr);
+          }
+        }else{
+          /* %T means a Token pointer */
+          Token *pToken = va_arg(ap, Token*);
+          assert( bArgList==0 );
+          if( pToken && pToken->n ){
+            sqlite3_str_append(pAccum, (const char*)pToken->z, pToken->n);
+            sqlite3RecordErrorByteOffset(pAccum->db, pToken->z);
+          }
+        }
+        length = width = 0;
+        break;
+      }
+      case etSRCITEM: {
+        SrcItem *pItem;
+        if( (pAccum->printfFlags & SQLITE_PRINTF_INTERNAL)==0 ) return;
+        pItem = va_arg(ap, SrcItem*);
+        assert( bArgList==0 );
+        if( pItem->zAlias && !flag_altform2 ){
+          sqlite3_str_appendall(pAccum, pItem->zAlias);
+        }else if( pItem->zName ){
+          if( pItem->fg.fixedSchema==0
+           && pItem->fg.isSubquery==0
+           && pItem->u4.zDatabase!=0
+          ){
+            sqlite3_str_appendall(pAccum, pItem->u4.zDatabase);
+            sqlite3_str_append(pAccum, ".", 1);
+          }
+          sqlite3_str_appendall(pAccum, pItem->zName);
+        }else if( pItem->zAlias ){
+          sqlite3_str_appendall(pAccum, pItem->zAlias);
+        }else if( ALWAYS(pItem->fg.isSubquery) ){/* Because of tag-20240424-1 */
+          Select *pSel = pItem->u4.pSubq->pSelect;
+          assert( pSel!=0 );
+          if( pSel->selFlags & SF_NestedFrom ){
+            sqlite3_str_appendf(pAccum, "(join-%u)", pSel->selId);
+          }else if( pSel->selFlags & SF_MultiValue ){
+            assert( !pItem->fg.isTabFunc && !pItem->fg.isIndexedBy );
+            sqlite3_str_appendf(pAccum, "%u-ROW VALUES CLAUSE",
+                                pItem->u1.nRow);
+          }else{
+            sqlite3_str_appendf(pAccum, "(subquery-%u)", pSel->selId);
+          }
+        }
+        length = width = 0;
+        break;
+      }
+      default: {
+        assert( xtype==etINVALID );
+        return;
+      }
+    }/* End switch over the format type */
+    /*
+    ** The text of the conversion is pointed to by "bufpt" and is
+    ** "length" characters long.  The field width is "width".  Do
+    ** the output.  Both length and width are in bytes, not characters,
+    ** at this point.  If the "!" flag was present on string conversions
+    ** indicating that width and precision should be expressed in characters,
+    ** then the values have been translated prior to reaching this point.
+    */
+    width -= length;
+    if( width>0 ){
+      if( !flag_leftjustify ) sqlite3_str_appendchar(pAccum, width, ' ');
+      sqlite3_str_append(pAccum, bufpt, length);
+      if( flag_leftjustify ) sqlite3_str_appendchar(pAccum, width, ' ');
+    }else{
+      sqlite3_str_append(pAccum, bufpt, length);
+    }
+
+    if( zExtra ){
+      sqlite3DbFree(pAccum->db, zExtra);
+      zExtra = 0;
+    }
+  }/* End for loop over the format string */
+} /* End of function */
+
+
+/*
+** The z string points to the first character of a token that is
+** associated with an error.  If db does not already have an error
+** byte offset recorded, try to compute the error byte offset for
+** z and set the error byte offset in db.
+*/
+SQLITE_PRIVATE void sqlite3RecordErrorByteOffset(sqlite3 *db, const char *z){
+  const Parse *pParse;
+  const char *zText;
+  const char *zEnd;
+  assert( z!=0 );
+  if( NEVER(db==0) ) return;
+  if( db->errByteOffset!=(-2) ) return;
+  pParse = db->pParse;
+  if( NEVER(pParse==0) ) return;
+  zText =pParse->zTail;
+  if( NEVER(zText==0) ) return;
+  zEnd = &zText[strlen(zText)];
+  if( SQLITE_WITHIN(z,zText,zEnd) ){
+    db->errByteOffset = (int)(z-zText);
+  }
+}
+
+/*
+** If pExpr has a byte offset for the start of a token, record that as
+** as the error offset.
+*/
+SQLITE_PRIVATE void sqlite3RecordErrorOffsetOfExpr(sqlite3 *db, const Expr *pExpr){
+  while( pExpr
+     && (ExprHasProperty(pExpr,EP_OuterON|EP_InnerON) || pExpr->w.iOfst<=0)
+  ){
+    pExpr = pExpr->pLeft;
+  }
+  if( pExpr==0 ) return;
+  if( ExprHasProperty(pExpr, EP_FromDDL) ) return;
+  db->errByteOffset = pExpr->w.iOfst;
+}
+
+/*
+** Enlarge the memory allocation on a StrAccum object so that it is
+** able to accept at least N more bytes of text.
+**
+** Return the number of bytes of text that StrAccum is able to accept
+** after the attempted enlargement.  The value returned might be zero.
+*/
+SQLITE_PRIVATE int sqlite3StrAccumEnlarge(StrAccum *p, i64 N){
+  char *zNew;
+  assert( p->nChar+N >= p->nAlloc ); /* Only called if really needed */
+  if( p->accError ){
+    testcase(p->accError==SQLITE_TOOBIG);
+    testcase(p->accError==SQLITE_NOMEM);
+    return 0;
+  }
+  if( p->mxAlloc==0 ){
+    sqlite3StrAccumSetError(p, SQLITE_TOOBIG);
+    return p->nAlloc - p->nChar - 1;
+  }else{
+    char *zOld = isMalloced(p) ? p->zText : 0;
+    i64 szNew = p->nChar + N + 1;
+    if( szNew+p->nChar<=p->mxAlloc ){
+      /* Force exponential buffer size growth as long as it does not overflow,
+      ** to avoid having to call this routine too often */
+      szNew += p->nChar;
+    }
+    if( szNew > p->mxAlloc ){
+      sqlite3_str_reset(p);
+      sqlite3StrAccumSetError(p, SQLITE_TOOBIG);
+      return 0;
+    }else{
+      p->nAlloc = (int)szNew;
+    }
+    if( p->db ){
+      zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
+    }else{
+      zNew = sqlite3Realloc(zOld, p->nAlloc);
+    }
+    if( zNew ){
+      assert( p->zText!=0 || p->nChar==0 );
+      if( !isMalloced(p) && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
+      p->zText = zNew;
+      p->nAlloc = sqlite3DbMallocSize(p->db, zNew);
+      p->printfFlags |= SQLITE_PRINTF_MALLOCED;
+    }else{
+      sqlite3_str_reset(p);
+      sqlite3StrAccumSetError(p, SQLITE_NOMEM);
+      return 0;
+    }
+  }
+  assert( N>=0 && N<=0x7fffffff );
+  return (int)N;
+}
+
+/*
+** Append N copies of character c to the given string buffer.
+*/
+SQLITE_API void sqlite3_str_appendchar(sqlite3_str *p, int N, char c){
+  testcase( p->nChar + (i64)N > 0x7fffffff );
+  if( p->nChar+(i64)N >= p->nAlloc && (N = sqlite3StrAccumEnlarge(p, N))<=0 ){
+    return;
+  }
+  while( (N--)>0 ) p->zText[p->nChar++] = c;
+}
+
+/*
+** The StrAccum "p" is not large enough to accept N new bytes of z[].
+** So enlarge if first, then do the append.
+**
+** This is a helper routine to sqlite3_str_append() that does special-case
+** work (enlarging the buffer) using tail recursion, so that the
+** sqlite3_str_append() routine can use fast calling semantics.
+*/
+static void SQLITE_NOINLINE enlargeAndAppend(StrAccum *p, const char *z, int N){
+  N = sqlite3StrAccumEnlarge(p, N);
+  if( N>0 ){
+    memcpy(&p->zText[p->nChar], z, N);
+    p->nChar += N;
+  }
+}
+
+/*
+** Append N bytes of text from z to the StrAccum object.  Increase the
+** size of the memory allocation for StrAccum if necessary.
+*/
+SQLITE_API void sqlite3_str_append(sqlite3_str *p, const char *z, int N){
+  assert( z!=0 || N==0 );
+  assert( p->zText!=0 || p->nChar==0 || p->accError );
+  assert( N>=0 );
+  assert( p->accError==0 || p->nAlloc==0 || p->mxAlloc==0 );
+  if( p->nChar+N >= p->nAlloc ){
+    enlargeAndAppend(p,z,N);
+  }else if( N ){
+    assert( p->zText );
+    p->nChar += N;
+    memcpy(&p->zText[p->nChar-N], z, N);
+  }
+}
+
+/*
+** Append the complete text of zero-terminated string z[] to the p string.
+*/
+SQLITE_API void sqlite3_str_appendall(sqlite3_str *p, const char *z){
+  sqlite3_str_append(p, z, sqlite3Strlen30(z));
+}
+
+
+/*
+** Finish off a string by making sure it is zero-terminated.
+** Return a pointer to the resulting string.  Return a NULL
+** pointer if any kind of error was encountered.
+*/
+static SQLITE_NOINLINE char *strAccumFinishRealloc(StrAccum *p){
+  char *zText;
+  assert( p->mxAlloc>0 && !isMalloced(p) );
+  zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
+  if( zText ){
+    memcpy(zText, p->zText, p->nChar+1);
+    p->printfFlags |= SQLITE_PRINTF_MALLOCED;
+  }else{
+    sqlite3StrAccumSetError(p, SQLITE_NOMEM);
+  }
+  p->zText = zText;
+  return zText;
+}
+SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum *p){
+  if( p->zText ){
+    p->zText[p->nChar] = 0;
+    if( p->mxAlloc>0 && !isMalloced(p) ){
+      return strAccumFinishRealloc(p);
+    }
+  }
+  return p->zText;
+}
+
+/*
+** Use the content of the StrAccum passed as the second argument
+** as the result of an SQL function.
+*/
+SQLITE_PRIVATE void sqlite3ResultStrAccum(sqlite3_context *pCtx, StrAccum *p){
+  if( p->accError ){
+    sqlite3_result_error_code(pCtx, p->accError);
+    sqlite3_str_reset(p);
+  }else if( isMalloced(p) ){
+    sqlite3_result_text(pCtx, p->zText, p->nChar, SQLITE_DYNAMIC);
+  }else{
+    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
+    sqlite3_str_reset(p);
+  }
+}
+
+/*
+** This singleton is an sqlite3_str object that is returned if
+** sqlite3_malloc() fails to provide space for a real one.  This
+** sqlite3_str object accepts no new text and always returns
+** an SQLITE_NOMEM error.
+*/
+static sqlite3_str sqlite3OomStr = {
+   0, 0, 0, 0, 0, SQLITE_NOMEM, 0
+};
+
+/* Finalize a string created using sqlite3_str_new().
+*/
+SQLITE_API char *sqlite3_str_finish(sqlite3_str *p){
+  char *z;
+  if( p!=0 && p!=&sqlite3OomStr ){
+    z = sqlite3StrAccumFinish(p);
+    sqlite3_free(p);
+  }else{
+    z = 0;
+  }
+  return z;
+}
+
+/* Return any error code associated with p */
+SQLITE_API int sqlite3_str_errcode(sqlite3_str *p){
+  return p ? p->accError : SQLITE_NOMEM;
+}
+
+/* Return the current length of p in bytes */
+SQLITE_API int sqlite3_str_length(sqlite3_str *p){
+  return p ? p->nChar : 0;
+}
+
+/* Return the current value for p */
+SQLITE_API char *sqlite3_str_value(sqlite3_str *p){
+  if( p==0 || p->nChar==0 ) return 0;
+  p->zText[p->nChar] = 0;
+  return p->zText;
+}
+
+/*
+** Reset an StrAccum string.  Reclaim all malloced memory.
+*/
+SQLITE_API void sqlite3_str_reset(StrAccum *p){
+  if( isMalloced(p) ){
+    sqlite3DbFree(p->db, p->zText);
+    p->printfFlags &= ~SQLITE_PRINTF_MALLOCED;
+  }
+  p->nAlloc = 0;
+  p->nChar = 0;
+  p->zText = 0;
+}
+
+/*
+** Initialize a string accumulator.
+**
+** p:     The accumulator to be initialized.
+** db:    Pointer to a database connection.  May be NULL.  Lookaside
+**        memory is used if not NULL. db->mallocFailed is set appropriately
+**        when not NULL.
+** zBase: An initial buffer.  May be NULL in which case the initial buffer
+**        is malloced.
+** n:     Size of zBase in bytes.  If total space requirements never exceed
+**        n then no memory allocations ever occur.
+** mx:    Maximum number of bytes to accumulate.  If mx==0 then no memory
+**        allocations will ever occur.
+*/
+SQLITE_PRIVATE void sqlite3StrAccumInit(StrAccum *p, sqlite3 *db, char *zBase, int n, int mx){
+  p->zText = zBase;
+  p->db = db;
+  p->nAlloc = n;
+  p->mxAlloc = mx;
+  p->nChar = 0;
+  p->accError = 0;
+  p->printfFlags = 0;
+}
+
+/* Allocate and initialize a new dynamic string object */
+SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3 *db){
+  sqlite3_str *p = sqlite3_malloc64(sizeof(*p));
+  if( p ){
+    sqlite3StrAccumInit(p, 0, 0, 0,
+            db ? db->aLimit[SQLITE_LIMIT_LENGTH] : SQLITE_MAX_LENGTH);
+  }else{
+    p = &sqlite3OomStr;
+  }
+  return p;
+}
+
+/*
+** Print into memory obtained from sqliteMalloc().  Use the internal
+** %-conversion extensions.
+*/
+SQLITE_PRIVATE char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){
+  char *z;
+  char zBase[SQLITE_PRINT_BUF_SIZE];
+  StrAccum acc;
+  assert( db!=0 );
+  sqlite3StrAccumInit(&acc, db, zBase, sizeof(zBase),
+                      db->aLimit[SQLITE_LIMIT_LENGTH]);
+  acc.printfFlags = SQLITE_PRINTF_INTERNAL;
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  z = sqlite3StrAccumFinish(&acc);
+  if( acc.accError==SQLITE_NOMEM ){
+    sqlite3OomFault(db);
+  }
+  return z;
+}
+
+/*
+** Print into memory obtained from sqliteMalloc().  Use the internal
+** %-conversion extensions.
+*/
+SQLITE_PRIVATE char *sqlite3MPrintf(sqlite3 *db, const char *zFormat, ...){
+  va_list ap;
+  char *z;
+  va_start(ap, zFormat);
+  z = sqlite3VMPrintf(db, zFormat, ap);
+  va_end(ap);
+  return z;
+}
+
+/*
+** Print into memory obtained from sqlite3_malloc().  Omit the internal
+** %-conversion extensions.
+*/
+SQLITE_API char *sqlite3_vmprintf(const char *zFormat, va_list ap){
+  char *z;
+  char zBase[SQLITE_PRINT_BUF_SIZE];
+  StrAccum acc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zFormat==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  sqlite3StrAccumInit(&acc, 0, zBase, sizeof(zBase), SQLITE_MAX_LENGTH);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  z = sqlite3StrAccumFinish(&acc);
+  return z;
+}
+
+/*
+** Print into memory obtained from sqlite3_malloc()().  Omit the internal
+** %-conversion extensions.
+*/
+SQLITE_API char *sqlite3_mprintf(const char *zFormat, ...){
+  va_list ap;
+  char *z;
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  va_start(ap, zFormat);
+  z = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+  return z;
+}
+
+/*
+** sqlite3_snprintf() works like snprintf() except that it ignores the
+** current locale settings.  This is important for SQLite because we
+** are not able to use a "," as the decimal point in place of "." as
+** specified by some locales.
+**
+** Oops:  The first two arguments of sqlite3_snprintf() are backwards
+** from the snprintf() standard.  Unfortunately, it is too late to change
+** this without breaking compatibility, so we just have to live with the
+** mistake.
+**
+** sqlite3_vsnprintf() is the varargs version.
+*/
+SQLITE_API char *sqlite3_vsnprintf(int n, char *zBuf, const char *zFormat, va_list ap){
+  StrAccum acc;
+  if( n<=0 ) return zBuf;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zBuf==0 || zFormat==0 ) {
+    (void)SQLITE_MISUSE_BKPT;
+    if( zBuf ) zBuf[0] = 0;
+    return zBuf;
+  }
+#endif
+  sqlite3StrAccumInit(&acc, 0, zBuf, n, 0);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  zBuf[acc.nChar] = 0;
+  return zBuf;
+}
+SQLITE_API char *sqlite3_snprintf(int n, char *zBuf, const char *zFormat, ...){
+  StrAccum acc;
+  va_list ap;
+  if( n<=0 ) return zBuf;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zBuf==0 || zFormat==0 ) {
+    (void)SQLITE_MISUSE_BKPT;
+    if( zBuf ) zBuf[0] = 0;
+    return zBuf;
+  }
+#endif
+  sqlite3StrAccumInit(&acc, 0, zBuf, n, 0);
+  va_start(ap,zFormat);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  va_end(ap);
+  zBuf[acc.nChar] = 0;
+  return zBuf;
+}
+
+/*
+** This is the routine that actually formats the sqlite3_log() message.
+** We house it in a separate routine from sqlite3_log() to avoid using
+** stack space on small-stack systems when logging is disabled.
+**
+** sqlite3_log() must render into a static buffer.  It cannot dynamically
+** allocate memory because it might be called while the memory allocator
+** mutex is held.
+**
+** sqlite3_str_vappendf() might ask for *temporary* memory allocations for
+** certain format characters (%q) or for very large precisions or widths.
+** Care must be taken that any sqlite3_log() calls that occur while the
+** memory mutex is held do not use these mechanisms.
+*/
+static void renderLogMsg(int iErrCode, const char *zFormat, va_list ap){
+  StrAccum acc;                          /* String accumulator */
+  char zMsg[SQLITE_PRINT_BUF_SIZE*3];    /* Complete log message */
+
+  sqlite3StrAccumInit(&acc, 0, zMsg, sizeof(zMsg), 0);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  sqlite3GlobalConfig.xLog(sqlite3GlobalConfig.pLogArg, iErrCode,
+                           sqlite3StrAccumFinish(&acc));
+}
+
+/*
+** Format and write a message to the log if logging is enabled.
+*/
+SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...){
+  va_list ap;                             /* Vararg list */
+  if( sqlite3GlobalConfig.xLog ){
+    va_start(ap, zFormat);
+    renderLogMsg(iErrCode, zFormat, ap);
+    va_end(ap);
+  }
+}
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+/*
+** A version of printf() that understands %lld.  Used for debugging.
+** The printf() built into some versions of windows does not understand %lld
+** and segfaults if you give it a long long int.
+*/
+SQLITE_PRIVATE void sqlite3DebugPrintf(const char *zFormat, ...){
+  va_list ap;
+  StrAccum acc;
+  char zBuf[SQLITE_PRINT_BUF_SIZE*10];
+  sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+  va_start(ap,zFormat);
+  sqlite3_str_vappendf(&acc, zFormat, ap);
+  va_end(ap);
+  sqlite3StrAccumFinish(&acc);
+#ifdef SQLITE_OS_TRACE_PROC
+  {
+    extern void SQLITE_OS_TRACE_PROC(const char *zBuf, int nBuf);
+    SQLITE_OS_TRACE_PROC(zBuf, sizeof(zBuf));
+  }
+#else
+  fprintf(stdout,"%s", zBuf);
+  fflush(stdout);
+#endif
+}
+#endif
+
+
+/*
+** variable-argument wrapper around sqlite3_str_vappendf(). The bFlags argument
+** can contain the bit SQLITE_PRINTF_INTERNAL enable internal formats.
+*/
+SQLITE_API void sqlite3_str_appendf(StrAccum *p, const char *zFormat, ...){
+  va_list ap;
+  va_start(ap,zFormat);
+  sqlite3_str_vappendf(p, zFormat, ap);
+  va_end(ap);
+}
+
+
+/*****************************************************************************
+** Reference counted string/blob storage
+*****************************************************************************/
+
+/*
+** Increase the reference count of the string by one.
+**
+** The input parameter is returned.
+*/
+SQLITE_PRIVATE char *sqlite3RCStrRef(char *z){
+  RCStr *p = (RCStr*)z;
+  assert( p!=0 );
+  p--;
+  p->nRCRef++;
+  return z;
+}
+
+/*
+** Decrease the reference count by one.  Free the string when the
+** reference count reaches zero.
+*/
+SQLITE_PRIVATE void sqlite3RCStrUnref(void *z){
+  RCStr *p = (RCStr*)z;
+  assert( p!=0 );
+  p--;
+  assert( p->nRCRef>0 );
+  if( p->nRCRef>=2 ){
+    p->nRCRef--;
+  }else{
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Create a new string that is capable of holding N bytes of text, not counting
+** the zero byte at the end.  The string is uninitialized.
+**
+** The reference count is initially 1.  Call sqlite3RCStrUnref() to free the
+** newly allocated string.
+**
+** This routine returns 0 on an OOM.
+*/
+SQLITE_PRIVATE char *sqlite3RCStrNew(u64 N){
+  RCStr *p = sqlite3_malloc64( N + sizeof(*p) + 1 );
+  if( p==0 ) return 0;
+  p->nRCRef = 1;
+  return (char*)&p[1];
+}
+
+/*
+** Change the size of the string so that it is able to hold N bytes.
+** The string might be reallocated, so return the new allocation.
+*/
+SQLITE_PRIVATE char *sqlite3RCStrResize(char *z, u64 N){
+  RCStr *p = (RCStr*)z;
+  RCStr *pNew;
+  assert( p!=0 );
+  p--;
+  assert( p->nRCRef==1 );
+  pNew = sqlite3_realloc64(p, N+sizeof(RCStr)+1);
+  if( pNew==0 ){
+    sqlite3_free(p);
+    return 0;
+  }else{
+    return (char*)&pNew[1];
+  }
+}
+
+/************** End of printf.c **********************************************/
+/************** Begin file treeview.c ****************************************/
+/*
+** 2015-06-08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains C code to implement the TreeView debugging routines.
+** These routines print a parse tree to standard output for debugging and
+** analysis.
+**
+** The interfaces in this file is only available when compiling
+** with SQLITE_DEBUG.
+*/
+/* #include "sqliteInt.h" */
+#ifdef SQLITE_DEBUG
+
+/*
+** Add a new subitem to the tree.  The moreToFollow flag indicates that this
+** is not the last item in the tree.
+*/
+static void sqlite3TreeViewPush(TreeView **pp, u8 moreToFollow){
+  TreeView *p = *pp;
+  if( p==0 ){
+    *pp = p = sqlite3_malloc64( sizeof(*p) );
+    if( p==0 ) return;
+    memset(p, 0, sizeof(*p));
+  }else{
+    p->iLevel++;
+  }
+  assert( moreToFollow==0 || moreToFollow==1 );
+  if( p->iLevel<(int)sizeof(p->bLine) ) p->bLine[p->iLevel] = moreToFollow;
+}
+
+/*
+** Finished with one layer of the tree
+*/
+static void sqlite3TreeViewPop(TreeView **pp){
+  TreeView *p = *pp;
+  if( p==0 ) return;
+  p->iLevel--;
+  if( p->iLevel<0 ){
+    sqlite3_free(p);
+    *pp = 0;
+  }
+}
+
+/*
+** Generate a single line of output for the tree, with a prefix that contains
+** all the appropriate tree lines
+*/
+SQLITE_PRIVATE void sqlite3TreeViewLine(TreeView *p, const char *zFormat, ...){
+  va_list ap;
+  int i;
+  StrAccum acc;
+  char zBuf[1000];
+  sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+  if( p ){
+    for(i=0; i<p->iLevel && i<(int)sizeof(p->bLine)-1; i++){
+      sqlite3_str_append(&acc, p->bLine[i] ? "|   " : "    ", 4);
+    }
+    sqlite3_str_append(&acc, p->bLine[i] ? "|-- " : "'-- ", 4);
+  }
+  if( zFormat!=0 ){
+    va_start(ap, zFormat);
+    sqlite3_str_vappendf(&acc, zFormat, ap);
+    va_end(ap);
+    assert( acc.nChar>0 || acc.accError );
+    sqlite3_str_append(&acc, "\n", 1);
+  }
+  sqlite3StrAccumFinish(&acc);
+  fprintf(stdout,"%s", zBuf);
+  fflush(stdout);
+}
+
+/*
+** Shorthand for starting a new tree item that consists of a single label
+*/
+static void sqlite3TreeViewItem(TreeView *p, const char *zLabel,u8 moreFollows){
+  sqlite3TreeViewPush(&p, moreFollows);
+  sqlite3TreeViewLine(p, "%s", zLabel);
+}
+
+/*
+** Show a list of Column objects in tree format.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewColumnList(
+  TreeView *pView,
+  const Column *aCol,
+  int nCol,
+  u8 moreToFollow
+){
+  int i;
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  sqlite3TreeViewLine(pView, "COLUMNS");
+  for(i=0; i<nCol; i++){
+    u16 flg = aCol[i].colFlags;
+    int colMoreToFollow = i<(nCol - 1);
+    sqlite3TreeViewPush(&pView, colMoreToFollow);
+    sqlite3TreeViewLine(pView, 0);
+    printf(" %s", aCol[i].zCnName);
+    switch( aCol[i].eCType ){
+      case COLTYPE_ANY:      printf(" ANY");        break;
+      case COLTYPE_BLOB:     printf(" BLOB");       break;
+      case COLTYPE_INT:      printf(" INT");        break;
+      case COLTYPE_INTEGER:  printf(" INTEGER");    break;
+      case COLTYPE_REAL:     printf(" REAL");       break;
+      case COLTYPE_TEXT:     printf(" TEXT");       break;
+      case COLTYPE_CUSTOM: {
+        if( flg & COLFLAG_HASTYPE ){
+          const char *z = aCol[i].zCnName;
+          z += strlen(z)+1;
+          printf(" X-%s", z);
+          break;
+        }
+      }
+    }
+    if( flg & COLFLAG_PRIMKEY ) printf(" PRIMARY KEY");
+    if( flg & COLFLAG_HIDDEN ) printf(" HIDDEN");
+#ifdef COLFLAG_NOEXPAND
+    if( flg & COLFLAG_NOEXPAND ) printf(" NO-EXPAND");
+#endif
+    if( flg ) printf(" flags=%04x", flg);
+    printf("\n");
+    fflush(stdout);
+    sqlite3TreeViewPop(&pView);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+
+/*
+** Generate a human-readable description of a WITH clause.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewWith(TreeView *pView, const With *pWith, u8 moreToFollow){
+  int i;
+  if( pWith==0 ) return;
+  if( pWith->nCte==0 ) return;
+  if( pWith->pOuter ){
+    sqlite3TreeViewLine(pView, "WITH (0x%p, pOuter=0x%p)",pWith,pWith->pOuter);
+  }else{
+    sqlite3TreeViewLine(pView, "WITH (0x%p)", pWith);
+  }
+  if( pWith->nCte>0 ){
+    sqlite3TreeViewPush(&pView, moreToFollow);
+    for(i=0; i<pWith->nCte; i++){
+      StrAccum x;
+      char zLine[1000];
+      const struct Cte *pCte = &pWith->a[i];
+      sqlite3StrAccumInit(&x, 0, zLine, sizeof(zLine), 0);
+      sqlite3_str_appendf(&x, "%s", pCte->zName);
+      if( pCte->pCols && pCte->pCols->nExpr>0 ){
+        char cSep = '(';
+        int j;
+        for(j=0; j<pCte->pCols->nExpr; j++){
+          sqlite3_str_appendf(&x, "%c%s", cSep, pCte->pCols->a[j].zEName);
+          cSep = ',';
+        }
+        sqlite3_str_appendf(&x, ")");
+      }
+      if( pCte->eM10d!=M10d_Any ){
+        sqlite3_str_appendf(&x, " %sMATERIALIZED",
+           pCte->eM10d==M10d_No ? "NOT " : "");
+      }
+      if( pCte->pUse ){
+        sqlite3_str_appendf(&x, " (pUse=0x%p, nUse=%d)", pCte->pUse,
+                 pCte->pUse->nUse);
+      }
+      sqlite3StrAccumFinish(&x);
+      sqlite3TreeViewItem(pView, zLine, i<pWith->nCte-1);
+      sqlite3TreeViewSelect(pView, pCte->pSelect, 0);
+      sqlite3TreeViewPop(&pView);
+    }
+    sqlite3TreeViewPop(&pView);
+  }
+}
+
+/*
+** Generate a human-readable description of a SrcList object.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewSrcList(TreeView *pView, const SrcList *pSrc){
+  int i;
+  if( pSrc==0 ) return;
+  for(i=0; i<pSrc->nSrc; i++){
+    const SrcItem *pItem = &pSrc->a[i];
+    StrAccum x;
+    int n = 0;
+    char zLine[1000];
+    sqlite3StrAccumInit(&x, 0, zLine, sizeof(zLine), 0);
+    x.printfFlags |= SQLITE_PRINTF_INTERNAL;
+    sqlite3_str_appendf(&x, "{%d:*} %!S", pItem->iCursor, pItem);
+    if( pItem->pSTab ){
+      sqlite3_str_appendf(&x, " tab=%Q nCol=%d ptr=%p used=%llx%s",
+           pItem->pSTab->zName, pItem->pSTab->nCol, pItem->pSTab,
+           pItem->colUsed,
+           pItem->fg.rowidUsed ? "+rowid" : "");
+    }
+    if( (pItem->fg.jointype & (JT_LEFT|JT_RIGHT))==(JT_LEFT|JT_RIGHT) ){
+      sqlite3_str_appendf(&x, " FULL-OUTER-JOIN");
+    }else if( pItem->fg.jointype & JT_LEFT ){
+      sqlite3_str_appendf(&x, " LEFT-JOIN");
+    }else if( pItem->fg.jointype & JT_RIGHT ){
+      sqlite3_str_appendf(&x, " RIGHT-JOIN");
+    }else if( pItem->fg.jointype & JT_CROSS ){
+      sqlite3_str_appendf(&x, " CROSS-JOIN");
+    }
+    if( pItem->fg.jointype & JT_LTORJ ){
+      sqlite3_str_appendf(&x, " LTORJ");
+    }
+    if( pItem->fg.fromDDL ){
+      sqlite3_str_appendf(&x, " DDL");
+    }
+    if( pItem->fg.isCte ){
+      static const char *aMat[] = {",MAT", "", ",NO-MAT"};
+      sqlite3_str_appendf(&x, " CteUse=%d%s",
+                          pItem->u2.pCteUse->nUse,
+                          aMat[pItem->u2.pCteUse->eM10d]);
+    }
+    if( pItem->fg.isOn || (pItem->fg.isUsing==0 && pItem->u3.pOn!=0) ){
+      sqlite3_str_appendf(&x, " isOn");
+    }
+    if( pItem->fg.isTabFunc )      sqlite3_str_appendf(&x, " isTabFunc");
+    if( pItem->fg.isCorrelated )   sqlite3_str_appendf(&x, " isCorrelated");
+    if( pItem->fg.isMaterialized ) sqlite3_str_appendf(&x, " isMaterialized");
+    if( pItem->fg.viaCoroutine )   sqlite3_str_appendf(&x, " viaCoroutine");
+    if( pItem->fg.notCte )         sqlite3_str_appendf(&x, " notCte");
+    if( pItem->fg.isNestedFrom )   sqlite3_str_appendf(&x, " isNestedFrom");
+    if( pItem->fg.fixedSchema )    sqlite3_str_appendf(&x, " fixedSchema");
+    if( pItem->fg.hadSchema )      sqlite3_str_appendf(&x, " hadSchema");
+    if( pItem->fg.isSubquery )     sqlite3_str_appendf(&x, " isSubquery");
+
+    sqlite3StrAccumFinish(&x);
+    sqlite3TreeViewItem(pView, zLine, i<pSrc->nSrc-1);
+    n = 0;
+    if( pItem->fg.isSubquery ) n++;
+    if( pItem->fg.isTabFunc ) n++;
+    if( pItem->fg.isUsing ) n++;
+    if( pItem->fg.isUsing ){
+      sqlite3TreeViewIdList(pView, pItem->u3.pUsing, (--n)>0, "USING");
+    }
+    if( pItem->fg.isSubquery ){
+      assert( n==1 );
+      if( pItem->pSTab ){
+        Table *pTab = pItem->pSTab;
+        sqlite3TreeViewColumnList(pView, pTab->aCol, pTab->nCol, 1);
+      }
+      assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem) );
+      sqlite3TreeViewSelect(pView, pItem->u4.pSubq->pSelect, 0);
+    }
+    if( pItem->fg.isTabFunc ){
+      sqlite3TreeViewExprList(pView, pItem->u1.pFuncArg, 0, "func-args:");
+    }
+    sqlite3TreeViewPop(&pView);
+  }
+}
+
+/*
+** Generate a human-readable description of a Select object.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewSelect(TreeView *pView, const Select *p, u8 moreToFollow){
+  int n = 0;
+  int cnt = 0;
+  if( p==0 ){
+    sqlite3TreeViewLine(pView, "nil-SELECT");
+    return;
+  }
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  if( p->pWith ){
+    sqlite3TreeViewWith(pView, p->pWith, 1);
+    cnt = 1;
+    sqlite3TreeViewPush(&pView, 1);
+  }
+  do{
+    if( p->selFlags & SF_WhereBegin ){
+      sqlite3TreeViewLine(pView, "sqlite3WhereBegin()");
+    }else{
+      sqlite3TreeViewLine(pView,
+        "SELECT%s%s (%u/%p) selFlags=0x%x nSelectRow=%d",
+        ((p->selFlags & SF_Distinct) ? " DISTINCT" : ""),
+        ((p->selFlags & SF_Aggregate) ? " agg_flag" : ""),
+        p->selId, p, p->selFlags,
+        (int)p->nSelectRow
+      );
+    }
+    if( cnt++ ) sqlite3TreeViewPop(&pView);
+    if( p->pPrior ){
+      n = 1000;
+    }else{
+      n = 0;
+      if( p->pSrc && p->pSrc->nSrc && p->pSrc->nAlloc ) n++;
+      if( p->pWhere ) n++;
+      if( p->pGroupBy ) n++;
+      if( p->pHaving ) n++;
+      if( p->pOrderBy ) n++;
+      if( p->pLimit ) n++;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( p->pWin ) n++;
+      if( p->pWinDefn ) n++;
+#endif
+    }
+    if( p->pEList ){
+      sqlite3TreeViewExprList(pView, p->pEList, n>0, "result-set");
+    }
+    n--;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( p->pWin ){
+      Window *pX;
+      sqlite3TreeViewPush(&pView, (n--)>0);
+      sqlite3TreeViewLine(pView, "window-functions");
+      for(pX=p->pWin; pX; pX=pX->pNextWin){
+        sqlite3TreeViewWinFunc(pView, pX, pX->pNextWin!=0);
+      }
+      sqlite3TreeViewPop(&pView);
+    }
+#endif
+    if( p->pSrc && p->pSrc->nSrc && p->pSrc->nAlloc ){
+      sqlite3TreeViewPush(&pView, (n--)>0);
+      sqlite3TreeViewLine(pView, "FROM");
+      sqlite3TreeViewSrcList(pView, p->pSrc);
+      sqlite3TreeViewPop(&pView);
+    }
+    if( p->pWhere ){
+      sqlite3TreeViewItem(pView, "WHERE", (n--)>0);
+      sqlite3TreeViewExpr(pView, p->pWhere, 0);
+      sqlite3TreeViewPop(&pView);
+    }
+    if( p->pGroupBy ){
+      sqlite3TreeViewExprList(pView, p->pGroupBy, (n--)>0, "GROUPBY");
+    }
+    if( p->pHaving ){
+      sqlite3TreeViewItem(pView, "HAVING", (n--)>0);
+      sqlite3TreeViewExpr(pView, p->pHaving, 0);
+      sqlite3TreeViewPop(&pView);
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( p->pWinDefn ){
+      Window *pX;
+      sqlite3TreeViewItem(pView, "WINDOW", (n--)>0);
+      for(pX=p->pWinDefn; pX; pX=pX->pNextWin){
+        sqlite3TreeViewWindow(pView, pX, pX->pNextWin!=0);
+      }
+      sqlite3TreeViewPop(&pView);
+    }
+#endif
+    if( p->pOrderBy ){
+      sqlite3TreeViewExprList(pView, p->pOrderBy, (n--)>0, "ORDERBY");
+    }
+    if( p->pLimit ){
+      sqlite3TreeViewItem(pView, "LIMIT", (n--)>0);
+      sqlite3TreeViewExpr(pView, p->pLimit->pLeft, p->pLimit->pRight!=0);
+      if( p->pLimit->pRight ){
+        sqlite3TreeViewItem(pView, "OFFSET", 0);
+        sqlite3TreeViewExpr(pView, p->pLimit->pRight, 0);
+        sqlite3TreeViewPop(&pView);
+      }
+      sqlite3TreeViewPop(&pView);
+    }
+    if( p->pPrior ){
+      const char *zOp = "UNION";
+      switch( p->op ){
+        case TK_ALL:         zOp = "UNION ALL";  break;
+        case TK_INTERSECT:   zOp = "INTERSECT";  break;
+        case TK_EXCEPT:      zOp = "EXCEPT";     break;
+      }
+      sqlite3TreeViewItem(pView, zOp, 1);
+    }
+    p = p->pPrior;
+  }while( p!=0 );
+  sqlite3TreeViewPop(&pView);
+}
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Generate a description of starting or stopping bounds
+*/
+SQLITE_PRIVATE void sqlite3TreeViewBound(
+  TreeView *pView,        /* View context */
+  u8 eBound,              /* UNBOUNDED, CURRENT, PRECEDING, FOLLOWING */
+  Expr *pExpr,            /* Value for PRECEDING or FOLLOWING */
+  u8 moreToFollow         /* True if more to follow */
+){
+  switch( eBound ){
+    case TK_UNBOUNDED: {
+      sqlite3TreeViewItem(pView, "UNBOUNDED", moreToFollow);
+      sqlite3TreeViewPop(&pView);
+      break;
+    }
+    case TK_CURRENT: {
+      sqlite3TreeViewItem(pView, "CURRENT", moreToFollow);
+      sqlite3TreeViewPop(&pView);
+      break;
+    }
+    case TK_PRECEDING: {
+      sqlite3TreeViewItem(pView, "PRECEDING", moreToFollow);
+      sqlite3TreeViewExpr(pView, pExpr, 0);
+      sqlite3TreeViewPop(&pView);
+      break;
+    }
+    case TK_FOLLOWING: {
+      sqlite3TreeViewItem(pView, "FOLLOWING", moreToFollow);
+      sqlite3TreeViewExpr(pView, pExpr, 0);
+      sqlite3TreeViewPop(&pView);
+      break;
+    }
+  }
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Generate a human-readable explanation for a Window object
+*/
+SQLITE_PRIVATE void sqlite3TreeViewWindow(TreeView *pView, const Window *pWin, u8 more){
+  int nElement = 0;
+  if( pWin==0 ) return;
+  if( pWin->pFilter ){
+    sqlite3TreeViewItem(pView, "FILTER", 1);
+    sqlite3TreeViewExpr(pView, pWin->pFilter, 0);
+    sqlite3TreeViewPop(&pView);
+    if( pWin->eFrmType==TK_FILTER ) return;
+  }
+  sqlite3TreeViewPush(&pView, more);
+  if( pWin->zName ){
+    sqlite3TreeViewLine(pView, "OVER %s (%p)", pWin->zName, pWin);
+  }else{
+    sqlite3TreeViewLine(pView, "OVER (%p)", pWin);
+  }
+  if( pWin->zBase )    nElement++;
+  if( pWin->pOrderBy ) nElement++;
+  if( pWin->eFrmType!=0 && pWin->eFrmType!=TK_FILTER ) nElement++;
+  if( pWin->eExclude ) nElement++;
+  if( pWin->zBase ){
+    sqlite3TreeViewPush(&pView, (--nElement)>0);
+    sqlite3TreeViewLine(pView, "window: %s", pWin->zBase);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pWin->pPartition ){
+    sqlite3TreeViewExprList(pView, pWin->pPartition, nElement>0,"PARTITION-BY");
+  }
+  if( pWin->pOrderBy ){
+    sqlite3TreeViewExprList(pView, pWin->pOrderBy, (--nElement)>0, "ORDER-BY");
+  }
+  if( pWin->eFrmType!=0 && pWin->eFrmType!=TK_FILTER ){
+    char zBuf[30];
+    const char *zFrmType = "ROWS";
+    if( pWin->eFrmType==TK_RANGE ) zFrmType = "RANGE";
+    if( pWin->eFrmType==TK_GROUPS ) zFrmType = "GROUPS";
+    sqlite3_snprintf(sizeof(zBuf),zBuf,"%s%s",zFrmType,
+        pWin->bImplicitFrame ? " (implied)" : "");
+    sqlite3TreeViewItem(pView, zBuf, (--nElement)>0);
+    sqlite3TreeViewBound(pView, pWin->eStart, pWin->pStart, 1);
+    sqlite3TreeViewBound(pView, pWin->eEnd, pWin->pEnd, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pWin->eExclude ){
+    char zBuf[30];
+    const char *zExclude;
+    switch( pWin->eExclude ){
+      case TK_NO:      zExclude = "NO OTHERS";   break;
+      case TK_CURRENT: zExclude = "CURRENT ROW"; break;
+      case TK_GROUP:   zExclude = "GROUP";       break;
+      case TK_TIES:    zExclude = "TIES";        break;
+      default:
+        sqlite3_snprintf(sizeof(zBuf),zBuf,"invalid(%d)", pWin->eExclude);
+        zExclude = zBuf;
+        break;
+    }
+    sqlite3TreeViewPush(&pView, 0);
+    sqlite3TreeViewLine(pView, "EXCLUDE %s", zExclude);
+    sqlite3TreeViewPop(&pView);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Generate a human-readable explanation for a Window Function object
+*/
+SQLITE_PRIVATE void sqlite3TreeViewWinFunc(TreeView *pView, const Window *pWin, u8 more){
+  if( pWin==0 ) return;
+  sqlite3TreeViewPush(&pView, more);
+  sqlite3TreeViewLine(pView, "WINFUNC %s(%d)",
+                       pWin->pWFunc->zName, pWin->pWFunc->nArg);
+  sqlite3TreeViewWindow(pView, pWin, 0);
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** Generate a human-readable explanation of an expression tree.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewExpr(TreeView *pView, const Expr *pExpr, u8 moreToFollow){
+  const char *zBinOp = 0;   /* Binary operator */
+  const char *zUniOp = 0;   /* Unary operator */
+  char zFlgs[200];
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  if( pExpr==0 ){
+    sqlite3TreeViewLine(pView, "nil");
+    sqlite3TreeViewPop(&pView);
+    return;
+  }
+  if( pExpr->flags || pExpr->affExpr || pExpr->vvaFlags || pExpr->pAggInfo ){
+    StrAccum x;
+    sqlite3StrAccumInit(&x, 0, zFlgs, sizeof(zFlgs), 0);
+    sqlite3_str_appendf(&x, " fg.af=%x.%c",
+      pExpr->flags, pExpr->affExpr ? pExpr->affExpr : 'n');
+    if( ExprHasProperty(pExpr, EP_OuterON) ){
+      sqlite3_str_appendf(&x, " outer.iJoin=%d", pExpr->w.iJoin);
+    }
+    if( ExprHasProperty(pExpr, EP_InnerON) ){
+      sqlite3_str_appendf(&x, " inner.iJoin=%d", pExpr->w.iJoin);
+    }
+    if( ExprHasProperty(pExpr, EP_FromDDL) ){
+      sqlite3_str_appendf(&x, " DDL");
+    }
+    if( ExprHasVVAProperty(pExpr, EP_Immutable) ){
+      sqlite3_str_appendf(&x, " IMMUTABLE");
+    }
+    if( pExpr->pAggInfo!=0 ){
+      sqlite3_str_appendf(&x, " agg-column[%d]", pExpr->iAgg);
+    }
+    sqlite3StrAccumFinish(&x);
+  }else{
+    zFlgs[0] = 0;
+  }
+  switch( pExpr->op ){
+    case TK_AGG_COLUMN: {
+      sqlite3TreeViewLine(pView, "AGG{%d:%d}%s",
+            pExpr->iTable, pExpr->iColumn, zFlgs);
+      break;
+    }
+    case TK_COLUMN: {
+      if( pExpr->iTable<0 ){
+        /* This only happens when coding check constraints */
+        char zOp2[16];
+        if( pExpr->op2 ){
+          sqlite3_snprintf(sizeof(zOp2),zOp2," op2=0x%02x",pExpr->op2);
+        }else{
+          zOp2[0] = 0;
+        }
+        sqlite3TreeViewLine(pView, "COLUMN(%d)%s%s",
+                                    pExpr->iColumn, zFlgs, zOp2);
+      }else{
+        assert( ExprUseYTab(pExpr) );
+        sqlite3TreeViewLine(pView, "{%d:%d} pTab=%p%s",
+                        pExpr->iTable, pExpr->iColumn,
+                        pExpr->y.pTab, zFlgs);
+      }
+      if( ExprHasProperty(pExpr, EP_FixedCol) ){
+        sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      }
+      break;
+    }
+    case TK_INTEGER: {
+      if( pExpr->flags & EP_IntValue ){
+        sqlite3TreeViewLine(pView, "%d", pExpr->u.iValue);
+      }else{
+        sqlite3TreeViewLine(pView, "%s", pExpr->u.zToken);
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    case TK_FLOAT: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"%s", pExpr->u.zToken);
+      break;
+    }
+#endif
+    case TK_STRING: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"%Q", pExpr->u.zToken);
+      break;
+    }
+    case TK_NULL: {
+      sqlite3TreeViewLine(pView,"NULL");
+      break;
+    }
+    case TK_TRUEFALSE: {
+      sqlite3TreeViewLine(pView,"%s%s",
+         sqlite3ExprTruthValue(pExpr) ? "TRUE" : "FALSE", zFlgs);
+      break;
+    }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case TK_BLOB: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"%s", pExpr->u.zToken);
+      break;
+    }
+#endif
+    case TK_VARIABLE: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"VARIABLE(%s,%d)",
+                          pExpr->u.zToken, pExpr->iColumn);
+      break;
+    }
+    case TK_REGISTER: {
+      sqlite3TreeViewLine(pView,"REGISTER(%d)", pExpr->iTable);
+      break;
+    }
+    case TK_ID: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"ID \"%w\"", pExpr->u.zToken);
+      break;
+    }
+#ifndef SQLITE_OMIT_CAST
+    case TK_CAST: {
+      /* Expressions of the form:   CAST(pLeft AS token) */
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView,"CAST %Q", pExpr->u.zToken);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+#endif /* SQLITE_OMIT_CAST */
+    case TK_LT:      zBinOp = "LT";     break;
+    case TK_LE:      zBinOp = "LE";     break;
+    case TK_GT:      zBinOp = "GT";     break;
+    case TK_GE:      zBinOp = "GE";     break;
+    case TK_NE:      zBinOp = "NE";     break;
+    case TK_EQ:      zBinOp = "EQ";     break;
+    case TK_IS:      zBinOp = "IS";     break;
+    case TK_ISNOT:   zBinOp = "ISNOT";  break;
+    case TK_AND:     zBinOp = "AND";    break;
+    case TK_OR:      zBinOp = "OR";     break;
+    case TK_PLUS:    zBinOp = "ADD";    break;
+    case TK_STAR:    zBinOp = "MUL";    break;
+    case TK_MINUS:   zBinOp = "SUB";    break;
+    case TK_REM:     zBinOp = "REM";    break;
+    case TK_BITAND:  zBinOp = "BITAND"; break;
+    case TK_BITOR:   zBinOp = "BITOR";  break;
+    case TK_SLASH:   zBinOp = "DIV";    break;
+    case TK_LSHIFT:  zBinOp = "LSHIFT"; break;
+    case TK_RSHIFT:  zBinOp = "RSHIFT"; break;
+    case TK_CONCAT:  zBinOp = "CONCAT"; break;
+    case TK_DOT:     zBinOp = "DOT";    break;
+    case TK_LIMIT:   zBinOp = "LIMIT";  break;
+
+    case TK_UMINUS:  zUniOp = "UMINUS"; break;
+    case TK_UPLUS:   zUniOp = "UPLUS";  break;
+    case TK_BITNOT:  zUniOp = "BITNOT"; break;
+    case TK_NOT:     zUniOp = "NOT";    break;
+    case TK_ISNULL:  zUniOp = "ISNULL"; break;
+    case TK_NOTNULL: zUniOp = "NOTNULL"; break;
+
+    case TK_TRUTH: {
+      int x;
+      const char *azOp[] = {
+         "IS-FALSE", "IS-TRUE", "IS-NOT-FALSE", "IS-NOT-TRUE"
+      };
+      assert( pExpr->op2==TK_IS || pExpr->op2==TK_ISNOT );
+      assert( pExpr->pRight );
+      assert( sqlite3ExprSkipCollateAndLikely(pExpr->pRight)->op
+                  == TK_TRUEFALSE );
+      x = (pExpr->op2==TK_ISNOT)*2 + sqlite3ExprTruthValue(pExpr->pRight);
+      zUniOp = azOp[x];
+      break;
+    }
+
+    case TK_SPAN: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView, "SPAN %Q", pExpr->u.zToken);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+
+    case TK_COLLATE: {
+      /* COLLATE operators without the EP_Collate flag are intended to
+      ** emulate collation associated with a table column.  These show
+      ** up in the treeview output as "SOFT-COLLATE".  Explicit COLLATE
+      ** operators that appear in the original SQL always have the
+      ** EP_Collate bit set and appear in treeview output as just "COLLATE" */
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView, "%sCOLLATE %Q%s",
+        !ExprHasProperty(pExpr, EP_Collate) ? "SOFT-" : "",
+        pExpr->u.zToken, zFlgs);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+
+    case TK_AGG_FUNCTION:
+    case TK_FUNCTION: {
+      ExprList *pFarg;       /* List of function arguments */
+      Window *pWin;
+      if( ExprHasProperty(pExpr, EP_TokenOnly) ){
+        pFarg = 0;
+        pWin = 0;
+      }else{
+        assert( ExprUseXList(pExpr) );
+        pFarg = pExpr->x.pList;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        pWin = IsWindowFunc(pExpr) ? pExpr->y.pWin : 0;
+#else
+        pWin = 0;
+#endif
+      }
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      if( pExpr->op==TK_AGG_FUNCTION ){
+        sqlite3TreeViewLine(pView, "AGG_FUNCTION%d %Q%s agg=%d[%d]/%p",
+                             pExpr->op2, pExpr->u.zToken, zFlgs,
+                             pExpr->pAggInfo ? pExpr->pAggInfo->selId : 0,
+                             pExpr->iAgg, pExpr->pAggInfo);
+      }else if( pExpr->op2!=0 ){
+        const char *zOp2;
+        char zBuf[8];
+        sqlite3_snprintf(sizeof(zBuf),zBuf,"0x%02x",pExpr->op2);
+        zOp2 = zBuf;
+        if( pExpr->op2==NC_IsCheck ) zOp2 = "NC_IsCheck";
+        if( pExpr->op2==NC_IdxExpr ) zOp2 = "NC_IdxExpr";
+        if( pExpr->op2==NC_PartIdx ) zOp2 = "NC_PartIdx";
+        if( pExpr->op2==NC_GenCol ) zOp2 = "NC_GenCol";
+        sqlite3TreeViewLine(pView, "FUNCTION %Q%s op2=%s",
+                            pExpr->u.zToken, zFlgs, zOp2);
+      }else{
+        sqlite3TreeViewLine(pView, "FUNCTION %Q%s", pExpr->u.zToken, zFlgs);
+      }
+      if( pFarg ){
+        sqlite3TreeViewExprList(pView, pFarg, pWin!=0 || pExpr->pLeft, 0);
+        if( pExpr->pLeft ){
+          Expr *pOB = pExpr->pLeft;
+          assert( pOB->op==TK_ORDER );
+          assert( ExprUseXList(pOB) );
+          sqlite3TreeViewExprList(pView, pOB->x.pList, pWin!=0, "ORDERBY");
+        }
+      }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( pWin ){
+        sqlite3TreeViewWindow(pView, pWin, 0);
+      }
+#endif
+      break;
+    }
+    case TK_ORDER: {
+      sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, "ORDERBY");
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_EXISTS: {
+      assert( ExprUseXSelect(pExpr) );
+      sqlite3TreeViewLine(pView, "EXISTS-expr flags=0x%x", pExpr->flags);
+      sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
+      break;
+    }
+    case TK_SELECT: {
+      assert( ExprUseXSelect(pExpr) );
+      sqlite3TreeViewLine(pView, "subquery-expr flags=0x%x", pExpr->flags);
+      sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
+      break;
+    }
+    case TK_IN: {
+      sqlite3_str *pStr = sqlite3_str_new(0);
+      char *z;
+      sqlite3_str_appendf(pStr, "IN flags=0x%x", pExpr->flags);
+      if( pExpr->iTable ) sqlite3_str_appendf(pStr, " iTable=%d",pExpr->iTable);
+      if( ExprHasProperty(pExpr, EP_Subrtn) ){
+        sqlite3_str_appendf(pStr, " subrtn(%d,%d)",
+            pExpr->y.sub.regReturn, pExpr->y.sub.iAddr);
+      }
+      z = sqlite3_str_finish(pStr);
+      sqlite3TreeViewLine(pView, z);
+      sqlite3_free(z);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
+      if( ExprUseXSelect(pExpr) ){
+        sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
+      }else{
+        sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, 0);
+      }
+      break;
+    }
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+    /*
+    **    x BETWEEN y AND z
+    **
+    ** This is equivalent to
+    **
+    **    x>=y AND x<=z
+    **
+    ** X is stored in pExpr->pLeft.
+    ** Y is stored in pExpr->pList->a[0].pExpr.
+    ** Z is stored in pExpr->pList->a[1].pExpr.
+    */
+    case TK_BETWEEN: {
+      const Expr *pX, *pY, *pZ;
+      pX = pExpr->pLeft;
+      assert( ExprUseXList(pExpr) );
+      assert( pExpr->x.pList->nExpr==2 );
+      pY = pExpr->x.pList->a[0].pExpr;
+      pZ = pExpr->x.pList->a[1].pExpr;
+      sqlite3TreeViewLine(pView, "BETWEEN%s", zFlgs);
+      sqlite3TreeViewExpr(pView, pX, 1);
+      sqlite3TreeViewExpr(pView, pY, 1);
+      sqlite3TreeViewExpr(pView, pZ, 0);
+      break;
+    }
+    case TK_TRIGGER: {
+      /* If the opcode is TK_TRIGGER, then the expression is a reference
+      ** to a column in the new.* or old.* pseudo-tables available to
+      ** trigger programs. In this case Expr.iTable is set to 1 for the
+      ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
+      ** is set to the column of the pseudo-table to read, or to -1 to
+      ** read the rowid field.
+      */
+      sqlite3TreeViewLine(pView, "%s(%d)",
+          pExpr->iTable ? "NEW" : "OLD", pExpr->iColumn);
+      break;
+    }
+    case TK_CASE: {
+      sqlite3TreeViewLine(pView, "CASE");
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
+      assert( ExprUseXList(pExpr) );
+      sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, 0);
+      break;
+    }
+#ifndef SQLITE_OMIT_TRIGGER
+    case TK_RAISE: {
+      const char *zType = "unk";
+      switch( pExpr->affExpr ){
+        case OE_Rollback:   zType = "rollback";  break;
+        case OE_Abort:      zType = "abort";     break;
+        case OE_Fail:       zType = "fail";      break;
+        case OE_Ignore:     zType = "ignore";    break;
+      }
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3TreeViewLine(pView, "RAISE %s", zType);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+#endif
+    case TK_MATCH: {
+      sqlite3TreeViewLine(pView, "MATCH {%d:%d}%s",
+                          pExpr->iTable, pExpr->iColumn, zFlgs);
+      sqlite3TreeViewExpr(pView, pExpr->pRight, 0);
+      break;
+    }
+    case TK_VECTOR: {
+      char *z = sqlite3_mprintf("VECTOR%s",zFlgs);
+      assert( ExprUseXList(pExpr) );
+      sqlite3TreeViewBareExprList(pView, pExpr->x.pList, z);
+      sqlite3_free(z);
+      break;
+    }
+    case TK_SELECT_COLUMN: {
+      sqlite3TreeViewLine(pView, "SELECT-COLUMN %d of [0..%d]%s",
+              pExpr->iColumn, pExpr->iTable-1,
+              pExpr->pRight==pExpr->pLeft ? " (SELECT-owner)" : "");
+      assert( ExprUseXSelect(pExpr->pLeft) );
+      sqlite3TreeViewSelect(pView, pExpr->pLeft->x.pSelect, 0);
+      break;
+    }
+    case TK_IF_NULL_ROW: {
+      sqlite3TreeViewLine(pView, "IF-NULL-ROW %d", pExpr->iTable);
+      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+      break;
+    }
+    case TK_ERROR: {
+      Expr tmp;
+      sqlite3TreeViewLine(pView, "ERROR");
+      tmp = *pExpr;
+      tmp.op = pExpr->op2;
+      sqlite3TreeViewExpr(pView, &tmp, 0);
+      break;
+    }
+    case TK_ROW: {
+      if( pExpr->iColumn<=0 ){
+        sqlite3TreeViewLine(pView, "First FROM table rowid");
+      }else{
+        sqlite3TreeViewLine(pView, "First FROM table column %d",
+            pExpr->iColumn-1);
+      }
+      break;
+    }
+    default: {
+      sqlite3TreeViewLine(pView, "op=%d", pExpr->op);
+      break;
+    }
+  }
+  if( zBinOp ){
+    sqlite3TreeViewLine(pView, "%s%s", zBinOp, zFlgs);
+    sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
+    sqlite3TreeViewExpr(pView, pExpr->pRight, 0);
+  }else if( zUniOp ){
+    sqlite3TreeViewLine(pView, "%s%s", zUniOp, zFlgs);
+   sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+
+
+/*
+** Generate a human-readable explanation of an expression list.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewBareExprList(
+  TreeView *pView,
+  const ExprList *pList,
+  const char *zLabel
+){
+  if( zLabel==0 || zLabel[0]==0 ) zLabel = "LIST";
+  if( pList==0 ){
+    sqlite3TreeViewLine(pView, "%s (empty)", zLabel);
+  }else{
+    int i;
+    sqlite3TreeViewLine(pView, "%s", zLabel);
+    for(i=0; i<pList->nExpr; i++){
+      int j = pList->a[i].u.x.iOrderByCol;
+      u8 sortFlags = pList->a[i].fg.sortFlags;
+      char *zName = pList->a[i].zEName;
+      int moreToFollow = i<pList->nExpr - 1;
+      if( j || zName || sortFlags ){
+        sqlite3TreeViewPush(&pView, moreToFollow);
+        moreToFollow = 0;
+        sqlite3TreeViewLine(pView, 0);
+        if( zName ){
+          switch( pList->a[i].fg.eEName ){
+            default:
+              fprintf(stdout, "AS %s ", zName);
+              break;
+            case ENAME_TAB:
+              fprintf(stdout, "TABLE-ALIAS-NAME(\"%s\") ", zName);
+              if( pList->a[i].fg.bUsed ) fprintf(stdout, "(used) ");
+              if( pList->a[i].fg.bUsingTerm ) fprintf(stdout, "(USING-term) ");
+              if( pList->a[i].fg.bNoExpand ) fprintf(stdout, "(NoExpand) ");
+              break;
+            case ENAME_SPAN:
+              fprintf(stdout, "SPAN(\"%s\") ", zName);
+              break;
+          }
+        }
+        if( j ){
+          fprintf(stdout, "iOrderByCol=%d ", j);
+        }
+        if( sortFlags & KEYINFO_ORDER_DESC ){
+          fprintf(stdout, "DESC ");
+        }else if( sortFlags & KEYINFO_ORDER_BIGNULL ){
+          fprintf(stdout, "NULLS-LAST");
+        }
+        fprintf(stdout, "\n");
+        fflush(stdout);
+      }
+      sqlite3TreeViewExpr(pView, pList->a[i].pExpr, moreToFollow);
+      if( j || zName || sortFlags ){
+        sqlite3TreeViewPop(&pView);
+      }
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3TreeViewExprList(
+  TreeView *pView,
+  const ExprList *pList,
+  u8 moreToFollow,
+  const char *zLabel
+){
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  sqlite3TreeViewBareExprList(pView, pList, zLabel);
+  sqlite3TreeViewPop(&pView);
+}
+
+/*
+** Generate a human-readable explanation of an id-list.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewBareIdList(
+  TreeView *pView,
+  const IdList *pList,
+  const char *zLabel
+){
+  if( zLabel==0 || zLabel[0]==0 ) zLabel = "LIST";
+  if( pList==0 ){
+    sqlite3TreeViewLine(pView, "%s (empty)", zLabel);
+  }else{
+    int i;
+    sqlite3TreeViewLine(pView, "%s", zLabel);
+    for(i=0; i<pList->nId; i++){
+      char *zName = pList->a[i].zName;
+      int moreToFollow = i<pList->nId - 1;
+      if( zName==0 ) zName = "(null)";
+      sqlite3TreeViewPush(&pView, moreToFollow);
+      sqlite3TreeViewLine(pView, 0);
+      fprintf(stdout, "%s\n", zName);
+      sqlite3TreeViewPop(&pView);
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3TreeViewIdList(
+  TreeView *pView,
+  const IdList *pList,
+  u8 moreToFollow,
+  const char *zLabel
+){
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  sqlite3TreeViewBareIdList(pView, pList, zLabel);
+  sqlite3TreeViewPop(&pView);
+}
+
+/*
+** Generate a human-readable explanation of a list of Upsert objects
+*/
+SQLITE_PRIVATE void sqlite3TreeViewUpsert(
+  TreeView *pView,
+  const Upsert *pUpsert,
+  u8 moreToFollow
+){
+  if( pUpsert==0 ) return;
+  sqlite3TreeViewPush(&pView, moreToFollow);
+  while( pUpsert ){
+    int n;
+    sqlite3TreeViewPush(&pView, pUpsert->pNextUpsert!=0 || moreToFollow);
+    sqlite3TreeViewLine(pView, "ON CONFLICT DO %s",
+         pUpsert->isDoUpdate ? "UPDATE" : "NOTHING");
+    n = (pUpsert->pUpsertSet!=0) + (pUpsert->pUpsertWhere!=0);
+    sqlite3TreeViewExprList(pView, pUpsert->pUpsertTarget, (n--)>0, "TARGET");
+    sqlite3TreeViewExprList(pView, pUpsert->pUpsertSet, (n--)>0, "SET");
+    if( pUpsert->pUpsertWhere ){
+      sqlite3TreeViewItem(pView, "WHERE", (n--)>0);
+      sqlite3TreeViewExpr(pView, pUpsert->pUpsertWhere, 0);
+      sqlite3TreeViewPop(&pView);
+    }
+    sqlite3TreeViewPop(&pView);
+    pUpsert = pUpsert->pNextUpsert;
+  }
+  sqlite3TreeViewPop(&pView);
+}
+
+#if TREETRACE_ENABLED
+/*
+** Generate a human-readable diagram of the data structure that go
+** into generating an DELETE statement.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewDelete(
+  const With *pWith,
+  const SrcList *pTabList,
+  const Expr *pWhere,
+  const ExprList *pOrderBy,
+  const Expr *pLimit,
+  const Trigger *pTrigger
+){
+  int n = 0;
+  TreeView *pView = 0;
+  sqlite3TreeViewPush(&pView, 0);
+  sqlite3TreeViewLine(pView, "DELETE");
+  if( pWith ) n++;
+  if( pTabList ) n++;
+  if( pWhere ) n++;
+  if( pOrderBy ) n++;
+  if( pLimit ) n++;
+  if( pTrigger ) n++;
+  if( pWith ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewWith(pView, pWith, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTabList ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "FROM");
+    sqlite3TreeViewSrcList(pView, pTabList);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pWhere ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "WHERE");
+    sqlite3TreeViewExpr(pView, pWhere, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pOrderBy ){
+    sqlite3TreeViewExprList(pView, pOrderBy, (--n)>0, "ORDER-BY");
+  }
+  if( pLimit ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "LIMIT");
+    sqlite3TreeViewExpr(pView, pLimit, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTrigger ){
+    sqlite3TreeViewTrigger(pView, pTrigger, (--n)>0, 1);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* TREETRACE_ENABLED */
+
+#if TREETRACE_ENABLED
+/*
+** Generate a human-readable diagram of the data structure that go
+** into generating an INSERT statement.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewInsert(
+  const With *pWith,
+  const SrcList *pTabList,
+  const IdList *pColumnList,
+  const Select *pSelect,
+  const ExprList *pExprList,
+  int onError,
+  const Upsert *pUpsert,
+  const Trigger *pTrigger
+){
+  TreeView *pView = 0;
+  int n = 0;
+  const char *zLabel = "INSERT";
+  switch( onError ){
+    case OE_Replace:  zLabel = "REPLACE";             break;
+    case OE_Ignore:   zLabel = "INSERT OR IGNORE";    break;
+    case OE_Rollback: zLabel = "INSERT OR ROLLBACK";  break;
+    case OE_Abort:    zLabel = "INSERT OR ABORT";     break;
+    case OE_Fail:     zLabel = "INSERT OR FAIL";      break;
+  }
+  sqlite3TreeViewPush(&pView, 0);
+  sqlite3TreeViewLine(pView, zLabel);
+  if( pWith ) n++;
+  if( pTabList ) n++;
+  if( pColumnList ) n++;
+  if( pSelect ) n++;
+  if( pExprList ) n++;
+  if( pUpsert ) n++;
+  if( pTrigger ) n++;
+  if( pWith ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewWith(pView, pWith, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTabList ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "INTO");
+    sqlite3TreeViewSrcList(pView, pTabList);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pColumnList ){
+    sqlite3TreeViewIdList(pView, pColumnList, (--n)>0, "COLUMNS");
+  }
+  if( pSelect ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "DATA-SOURCE");
+    sqlite3TreeViewSelect(pView, pSelect, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pExprList ){
+    sqlite3TreeViewExprList(pView, pExprList, (--n)>0, "VALUES");
+  }
+  if( pUpsert ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "UPSERT");
+    sqlite3TreeViewUpsert(pView, pUpsert, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTrigger ){
+    sqlite3TreeViewTrigger(pView, pTrigger, (--n)>0, 1);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* TREETRACE_ENABLED */
+
+#if TREETRACE_ENABLED
+/*
+** Generate a human-readable diagram of the data structure that go
+** into generating an UPDATE statement.
+*/
+SQLITE_PRIVATE void sqlite3TreeViewUpdate(
+  const With *pWith,
+  const SrcList *pTabList,
+  const ExprList *pChanges,
+  const Expr *pWhere,
+  int onError,
+  const ExprList *pOrderBy,
+  const Expr *pLimit,
+  const Upsert *pUpsert,
+  const Trigger *pTrigger
+){
+  int n = 0;
+  TreeView *pView = 0;
+  const char *zLabel = "UPDATE";
+  switch( onError ){
+    case OE_Replace:  zLabel = "UPDATE OR REPLACE";   break;
+    case OE_Ignore:   zLabel = "UPDATE OR IGNORE";    break;
+    case OE_Rollback: zLabel = "UPDATE OR ROLLBACK";  break;
+    case OE_Abort:    zLabel = "UPDATE OR ABORT";     break;
+    case OE_Fail:     zLabel = "UPDATE OR FAIL";      break;
+  }
+  sqlite3TreeViewPush(&pView, 0);
+  sqlite3TreeViewLine(pView, zLabel);
+  if( pWith ) n++;
+  if( pTabList ) n++;
+  if( pChanges ) n++;
+  if( pWhere ) n++;
+  if( pOrderBy ) n++;
+  if( pLimit ) n++;
+  if( pUpsert ) n++;
+  if( pTrigger ) n++;
+  if( pWith ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewWith(pView, pWith, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTabList ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "FROM");
+    sqlite3TreeViewSrcList(pView, pTabList);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pChanges ){
+    sqlite3TreeViewExprList(pView, pChanges, (--n)>0, "SET");
+  }
+  if( pWhere ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "WHERE");
+    sqlite3TreeViewExpr(pView, pWhere, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pOrderBy ){
+    sqlite3TreeViewExprList(pView, pOrderBy, (--n)>0, "ORDER-BY");
+  }
+  if( pLimit ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "LIMIT");
+    sqlite3TreeViewExpr(pView, pLimit, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pUpsert ){
+    sqlite3TreeViewPush(&pView, (--n)>0);
+    sqlite3TreeViewLine(pView, "UPSERT");
+    sqlite3TreeViewUpsert(pView, pUpsert, 0);
+    sqlite3TreeViewPop(&pView);
+  }
+  if( pTrigger ){
+    sqlite3TreeViewTrigger(pView, pTrigger, (--n)>0, 1);
+  }
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* TREETRACE_ENABLED */
+
+#ifndef SQLITE_OMIT_TRIGGER
+/*
+** Show a human-readable graph of a TriggerStep
+*/
+SQLITE_PRIVATE void sqlite3TreeViewTriggerStep(
+  TreeView *pView,
+  const TriggerStep *pStep,
+  u8 moreToFollow,
+  u8 showFullList
+){
+  int cnt = 0;
+  if( pStep==0 ) return;
+  sqlite3TreeViewPush(&pView,
+      moreToFollow || (showFullList && pStep->pNext!=0));
+  do{
+    if( cnt++ && pStep->pNext==0 ){
+      sqlite3TreeViewPop(&pView);
+      sqlite3TreeViewPush(&pView, 0);
+    }
+    sqlite3TreeViewLine(pView, "%s", pStep->zSpan ? pStep->zSpan : "RETURNING");
+  }while( showFullList && (pStep = pStep->pNext)!=0 );
+  sqlite3TreeViewPop(&pView);
+}
+
+/*
+** Show a human-readable graph of a Trigger
+*/
+SQLITE_PRIVATE void sqlite3TreeViewTrigger(
+  TreeView *pView,
+  const Trigger *pTrigger,
+  u8 moreToFollow,
+  u8 showFullList
+){
+  int cnt = 0;
+  if( pTrigger==0 ) return;
+  sqlite3TreeViewPush(&pView,
+     moreToFollow || (showFullList && pTrigger->pNext!=0));
+  do{
+    if( cnt++ && pTrigger->pNext==0 ){
+      sqlite3TreeViewPop(&pView);
+      sqlite3TreeViewPush(&pView, 0);
+    }
+    sqlite3TreeViewLine(pView, "TRIGGER %s", pTrigger->zName);
+    sqlite3TreeViewPush(&pView, 0);
+    sqlite3TreeViewTriggerStep(pView, pTrigger->step_list, 0, 1);
+    sqlite3TreeViewPop(&pView);
+  }while( showFullList && (pTrigger = pTrigger->pNext)!=0 );
+  sqlite3TreeViewPop(&pView);
+}
+#endif /* SQLITE_OMIT_TRIGGER */
+
+
+/*
+** These simplified versions of the tree-view routines omit unnecessary
+** parameters.  These variants are intended to be used from a symbolic
+** debugger, such as "gdb", during interactive debugging sessions.
+**
+** This routines are given external linkage so that they will always be
+** accessible to the debugging, and to avoid warnings about unused
+** functions.  But these routines only exist in debugging builds, so they
+** do not contaminate the interface.
+**
+** See Also:
+**
+**     sqlite3ShowWhereTerm() in where.c
+*/
+SQLITE_PRIVATE void sqlite3ShowExpr(const Expr *p){ sqlite3TreeViewExpr(0,p,0); }
+SQLITE_PRIVATE void sqlite3ShowExprList(const ExprList *p){ sqlite3TreeViewExprList(0,p,0,0);}
+SQLITE_PRIVATE void sqlite3ShowIdList(const IdList *p){ sqlite3TreeViewIdList(0,p,0,0); }
+SQLITE_PRIVATE void sqlite3ShowSrcList(const SrcList *p){ sqlite3TreeViewSrcList(0,p); }
+SQLITE_PRIVATE void sqlite3ShowSelect(const Select *p){ sqlite3TreeViewSelect(0,p,0); }
+SQLITE_PRIVATE void sqlite3ShowWith(const With *p){ sqlite3TreeViewWith(0,p,0); }
+SQLITE_PRIVATE void sqlite3ShowUpsert(const Upsert *p){ sqlite3TreeViewUpsert(0,p,0); }
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE void sqlite3ShowTriggerStep(const TriggerStep *p){
+  sqlite3TreeViewTriggerStep(0,p,0,0);
+}
+SQLITE_PRIVATE void sqlite3ShowTriggerStepList(const TriggerStep *p){
+  sqlite3TreeViewTriggerStep(0,p,0,1);
+}
+SQLITE_PRIVATE void sqlite3ShowTrigger(const Trigger *p){ sqlite3TreeViewTrigger(0,p,0,0); }
+SQLITE_PRIVATE void sqlite3ShowTriggerList(const Trigger *p){ sqlite3TreeViewTrigger(0,p,0,1);}
+#endif
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE void sqlite3ShowWindow(const Window *p){ sqlite3TreeViewWindow(0,p,0); }
+SQLITE_PRIVATE void sqlite3ShowWinFunc(const Window *p){ sqlite3TreeViewWinFunc(0,p,0); }
+#endif
+
+#endif /* SQLITE_DEBUG */
+
+/************** End of treeview.c ********************************************/
+/************** Begin file random.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code to implement a pseudo-random number
+** generator (PRNG) for SQLite.
+**
+** Random numbers are used by some of the database backends in order
+** to generate random integer keys for tables or random filenames.
+*/
+/* #include "sqliteInt.h" */
+
+
+/* All threads share a single random number generator.
+** This structure is the current state of the generator.
+*/
+static SQLITE_WSD struct sqlite3PrngType {
+  u32 s[16];                 /* 64 bytes of chacha20 state */
+  u8 out[64];                /* Output bytes */
+  u8 n;                      /* Output bytes remaining */
+} sqlite3Prng;
+
+
+/* The RFC-7539 ChaCha20 block function
+*/
+#define ROTL(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
+#define QR(a, b, c, d) ( \
+    a += b, d ^= a, d = ROTL(d,16), \
+    c += d, b ^= c, b = ROTL(b,12), \
+    a += b, d ^= a, d = ROTL(d, 8), \
+    c += d, b ^= c, b = ROTL(b, 7))
+static void chacha_block(u32 *out, const u32 *in){
+  int i;
+  u32 x[16];
+  memcpy(x, in, 64);
+  for(i=0; i<10; i++){
+    QR(x[0], x[4], x[ 8], x[12]);
+    QR(x[1], x[5], x[ 9], x[13]);
+    QR(x[2], x[6], x[10], x[14]);
+    QR(x[3], x[7], x[11], x[15]);
+    QR(x[0], x[5], x[10], x[15]);
+    QR(x[1], x[6], x[11], x[12]);
+    QR(x[2], x[7], x[ 8], x[13]);
+    QR(x[3], x[4], x[ 9], x[14]);
+  }
+  for(i=0; i<16; i++) out[i] = x[i]+in[i];
+}
+
+/*
+** Return N random bytes.
+*/
+SQLITE_API void sqlite3_randomness(int N, void *pBuf){
+  unsigned char *zBuf = pBuf;
+
+  /* The "wsdPrng" macro will resolve to the pseudo-random number generator
+  ** state vector.  If writable static data is unsupported on the target,
+  ** we have to locate the state vector at run-time.  In the more common
+  ** case where writable static data is supported, wsdPrng can refer directly
+  ** to the "sqlite3Prng" state vector declared above.
+  */
+#ifdef SQLITE_OMIT_WSD
+  struct sqlite3PrngType *p = &GLOBAL(struct sqlite3PrngType, sqlite3Prng);
+# define wsdPrng p[0]
+#else
+# define wsdPrng sqlite3Prng
+#endif
+
+#if SQLITE_THREADSAFE
+  sqlite3_mutex *mutex;
+#endif
+
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return;
+#endif
+
+#if SQLITE_THREADSAFE
+  mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_PRNG);
+#endif
+
+  sqlite3_mutex_enter(mutex);
+  if( N<=0 || pBuf==0 ){
+    wsdPrng.s[0] = 0;
+    sqlite3_mutex_leave(mutex);
+    return;
+  }
+
+  /* Initialize the state of the random number generator once,
+  ** the first time this routine is called.
+  */
+  if( wsdPrng.s[0]==0 ){
+    sqlite3_vfs *pVfs = sqlite3_vfs_find(0);
+    static const u32 chacha20_init[] = {
+      0x61707865, 0x3320646e, 0x79622d32, 0x6b206574
+    };
+    memcpy(&wsdPrng.s[0], chacha20_init, 16);
+    if( NEVER(pVfs==0) ){
+      memset(&wsdPrng.s[4], 0, 44);
+    }else{
+      sqlite3OsRandomness(pVfs, 44, (char*)&wsdPrng.s[4]);
+    }
+    wsdPrng.s[15] = wsdPrng.s[12];
+    wsdPrng.s[12] = 0;
+    wsdPrng.n = 0;
+  }
+
+  assert( N>0 );
+  while( 1 /* exit by break */ ){
+    if( N<=wsdPrng.n ){
+      memcpy(zBuf, &wsdPrng.out[wsdPrng.n-N], N);
+      wsdPrng.n -= N;
+      break;
+    }
+    if( wsdPrng.n>0 ){
+      memcpy(zBuf, wsdPrng.out, wsdPrng.n);
+      N -= wsdPrng.n;
+      zBuf += wsdPrng.n;
+    }
+    wsdPrng.s[12]++;
+    chacha_block((u32*)wsdPrng.out, wsdPrng.s);
+    wsdPrng.n = 64;
+  }
+  sqlite3_mutex_leave(mutex);
+}
+
+#ifndef SQLITE_UNTESTABLE
+/*
+** For testing purposes, we sometimes want to preserve the state of
+** PRNG and restore the PRNG to its saved state at a later time, or
+** to reset the PRNG to its initial state.  These routines accomplish
+** those tasks.
+**
+** The sqlite3_test_control() interface calls these routines to
+** control the PRNG.
+*/
+static SQLITE_WSD struct sqlite3PrngType sqlite3SavedPrng;
+SQLITE_PRIVATE void sqlite3PrngSaveState(void){
+  memcpy(
+    &GLOBAL(struct sqlite3PrngType, sqlite3SavedPrng),
+    &GLOBAL(struct sqlite3PrngType, sqlite3Prng),
+    sizeof(sqlite3Prng)
+  );
+}
+SQLITE_PRIVATE void sqlite3PrngRestoreState(void){
+  memcpy(
+    &GLOBAL(struct sqlite3PrngType, sqlite3Prng),
+    &GLOBAL(struct sqlite3PrngType, sqlite3SavedPrng),
+    sizeof(sqlite3Prng)
+  );
+}
+#endif /* SQLITE_UNTESTABLE */
+
+/************** End of random.c **********************************************/
+/************** Begin file threads.c *****************************************/
+/*
+** 2012 July 21
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file presents a simple cross-platform threading interface for
+** use internally by SQLite.
+**
+** A "thread" can be created using sqlite3ThreadCreate().  This thread
+** runs independently of its creator until it is joined using
+** sqlite3ThreadJoin(), at which point it terminates.
+**
+** Threads do not have to be real.  It could be that the work of the
+** "thread" is done by the main thread at either the sqlite3ThreadCreate()
+** or sqlite3ThreadJoin() call.  This is, in fact, what happens in
+** single threaded systems.  Nothing in SQLite requires multiple threads.
+** This interface exists so that applications that want to take advantage
+** of multiple cores can do so, while also allowing applications to stay
+** single-threaded if desired.
+*/
+/* #include "sqliteInt.h" */
+#if SQLITE_OS_WIN
+/* #  include "os_win.h" */
+#endif
+
+#if SQLITE_MAX_WORKER_THREADS>0
+
+/********************************* Unix Pthreads ****************************/
+#if SQLITE_OS_UNIX && defined(SQLITE_MUTEX_PTHREADS) && SQLITE_THREADSAFE>0
+
+#define SQLITE_THREADS_IMPLEMENTED 1  /* Prevent the single-thread code below */
+/* #include <pthread.h> */
+
+/* A running thread */
+struct SQLiteThread {
+  pthread_t tid;                 /* Thread ID */
+  int done;                      /* Set to true when thread finishes */
+  void *pOut;                    /* Result returned by the thread */
+  void *(*xTask)(void*);         /* The thread routine */
+  void *pIn;                     /* Argument to the thread */
+};
+
+/* Create a new thread */
+SQLITE_PRIVATE int sqlite3ThreadCreate(
+  SQLiteThread **ppThread,  /* OUT: Write the thread object here */
+  void *(*xTask)(void*),    /* Routine to run in a separate thread */
+  void *pIn                 /* Argument passed into xTask() */
+){
+  SQLiteThread *p;
+  int rc;
+
+  assert( ppThread!=0 );
+  assert( xTask!=0 );
+  /* This routine is never used in single-threaded mode */
+  assert( sqlite3GlobalConfig.bCoreMutex!=0 );
+
+  *ppThread = 0;
+  p = sqlite3Malloc(sizeof(*p));
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  memset(p, 0, sizeof(*p));
+  p->xTask = xTask;
+  p->pIn = pIn;
+  /* If the SQLITE_TESTCTRL_FAULT_INSTALL callback is registered to a
+  ** function that returns SQLITE_ERROR when passed the argument 200, that
+  ** forces worker threads to run sequentially and deterministically
+  ** for testing purposes. */
+  if( sqlite3FaultSim(200) ){
+    rc = 1;
+  }else{
+    rc = pthread_create(&p->tid, 0, xTask, pIn);
+  }
+  if( rc ){
+    p->done = 1;
+    p->pOut = xTask(pIn);
+  }
+  *ppThread = p;
+  return SQLITE_OK;
+}
+
+/* Get the results of the thread */
+SQLITE_PRIVATE int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){
+  int rc;
+
+  assert( ppOut!=0 );
+  if( NEVER(p==0) ) return SQLITE_NOMEM_BKPT;
+  if( p->done ){
+    *ppOut = p->pOut;
+    rc = SQLITE_OK;
+  }else{
+    rc = pthread_join(p->tid, ppOut) ? SQLITE_ERROR : SQLITE_OK;
+  }
+  sqlite3_free(p);
+  return rc;
+}
+
+#endif /* SQLITE_OS_UNIX && defined(SQLITE_MUTEX_PTHREADS) */
+/******************************** End Unix Pthreads *************************/
+
+
+/********************************* Win32 Threads ****************************/
+#if SQLITE_OS_WIN_THREADS
+
+#define SQLITE_THREADS_IMPLEMENTED 1  /* Prevent the single-thread code below */
+#include <process.h>
+
+/* A running thread */
+struct SQLiteThread {
+  void *tid;               /* The thread handle */
+  unsigned id;             /* The thread identifier */
+  void *(*xTask)(void*);   /* The routine to run as a thread */
+  void *pIn;               /* Argument to xTask */
+  void *pResult;           /* Result of xTask */
+};
+
+/* Thread procedure Win32 compatibility shim */
+static unsigned __stdcall sqlite3ThreadProc(
+  void *pArg  /* IN: Pointer to the SQLiteThread structure */
+){
+  SQLiteThread *p = (SQLiteThread *)pArg;
+
+  assert( p!=0 );
+#if 0
+  /*
+  ** This assert appears to trigger spuriously on certain
+  ** versions of Windows, possibly due to _beginthreadex()
+  ** and/or CreateThread() not fully setting their thread
+  ** ID parameter before starting the thread.
+  */
+  assert( p->id==GetCurrentThreadId() );
+#endif
+  assert( p->xTask!=0 );
+  p->pResult = p->xTask(p->pIn);
+
+  _endthreadex(0);
+  return 0; /* NOT REACHED */
+}
+
+/* Create a new thread */
+SQLITE_PRIVATE int sqlite3ThreadCreate(
+  SQLiteThread **ppThread,  /* OUT: Write the thread object here */
+  void *(*xTask)(void*),    /* Routine to run in a separate thread */
+  void *pIn                 /* Argument passed into xTask() */
+){
+  SQLiteThread *p;
+
+  assert( ppThread!=0 );
+  assert( xTask!=0 );
+  *ppThread = 0;
+  p = sqlite3Malloc(sizeof(*p));
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  /* If the SQLITE_TESTCTRL_FAULT_INSTALL callback is registered to a
+  ** function that returns SQLITE_ERROR when passed the argument 200, that
+  ** forces worker threads to run sequentially and deterministically
+  ** (via the sqlite3FaultSim() term of the conditional) for testing
+  ** purposes. */
+  if( sqlite3GlobalConfig.bCoreMutex==0 || sqlite3FaultSim(200) ){
+    memset(p, 0, sizeof(*p));
+  }else{
+    p->xTask = xTask;
+    p->pIn = pIn;
+    p->tid = (void*)_beginthreadex(0, 0, sqlite3ThreadProc, p, 0, &p->id);
+    if( p->tid==0 ){
+      memset(p, 0, sizeof(*p));
+    }
+  }
+  if( p->xTask==0 ){
+    p->id = GetCurrentThreadId();
+    p->pResult = xTask(pIn);
+  }
+  *ppThread = p;
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE DWORD sqlite3Win32Wait(HANDLE hObject); /* os_win.c */
+
+/* Get the results of the thread */
+SQLITE_PRIVATE int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){
+  DWORD rc;
+  BOOL bRc;
+
+  assert( ppOut!=0 );
+  if( NEVER(p==0) ) return SQLITE_NOMEM_BKPT;
+  if( p->xTask==0 ){
+    /* assert( p->id==GetCurrentThreadId() ); */
+    rc = WAIT_OBJECT_0;
+    assert( p->tid==0 );
+  }else{
+    assert( p->id!=0 && p->id!=GetCurrentThreadId() );
+    rc = sqlite3Win32Wait((HANDLE)p->tid);
+    assert( rc!=WAIT_IO_COMPLETION );
+    bRc = CloseHandle((HANDLE)p->tid);
+    assert( bRc );
+  }
+  if( rc==WAIT_OBJECT_0 ) *ppOut = p->pResult;
+  sqlite3_free(p);
+  return (rc==WAIT_OBJECT_0) ? SQLITE_OK : SQLITE_ERROR;
+}
+
+#endif /* SQLITE_OS_WIN_THREADS */
+/******************************** End Win32 Threads *************************/
+
+
+/********************************* Single-Threaded **************************/
+#ifndef SQLITE_THREADS_IMPLEMENTED
+/*
+** This implementation does not actually create a new thread.  It does the
+** work of the thread in the main thread, when either the thread is created
+** or when it is joined
+*/
+
+/* A running thread */
+struct SQLiteThread {
+  void *(*xTask)(void*);   /* The routine to run as a thread */
+  void *pIn;               /* Argument to xTask */
+  void *pResult;           /* Result of xTask */
+};
+
+/* Create a new thread */
+SQLITE_PRIVATE int sqlite3ThreadCreate(
+  SQLiteThread **ppThread,  /* OUT: Write the thread object here */
+  void *(*xTask)(void*),    /* Routine to run in a separate thread */
+  void *pIn                 /* Argument passed into xTask() */
+){
+  SQLiteThread *p;
+
+  assert( ppThread!=0 );
+  assert( xTask!=0 );
+  *ppThread = 0;
+  p = sqlite3Malloc(sizeof(*p));
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  if( (SQLITE_PTR_TO_INT(p)/17)&1 ){
+    p->xTask = xTask;
+    p->pIn = pIn;
+  }else{
+    p->xTask = 0;
+    p->pResult = xTask(pIn);
+  }
+  *ppThread = p;
+  return SQLITE_OK;
+}
+
+/* Get the results of the thread */
+SQLITE_PRIVATE int sqlite3ThreadJoin(SQLiteThread *p, void **ppOut){
+
+  assert( ppOut!=0 );
+  if( NEVER(p==0) ) return SQLITE_NOMEM_BKPT;
+  if( p->xTask ){
+    *ppOut = p->xTask(p->pIn);
+  }else{
+    *ppOut = p->pResult;
+  }
+  sqlite3_free(p);
+
+#if defined(SQLITE_TEST)
+  {
+    void *pTstAlloc = sqlite3Malloc(10);
+    if (!pTstAlloc) return SQLITE_NOMEM_BKPT;
+    sqlite3_free(pTstAlloc);
+  }
+#endif
+
+  return SQLITE_OK;
+}
+
+#endif /* !defined(SQLITE_THREADS_IMPLEMENTED) */
+/****************************** End Single-Threaded *************************/
+#endif /* SQLITE_MAX_WORKER_THREADS>0 */
+
+/************** End of threads.c *********************************************/
+/************** Begin file utf.c *********************************************/
+/*
+** 2004 April 13
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used to translate between UTF-8,
+** UTF-16, UTF-16BE, and UTF-16LE.
+**
+** Notes on UTF-8:
+**
+**   Byte-0    Byte-1    Byte-2    Byte-3    Value
+**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
+**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
+**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx
+**  11110uuu  10uuzzzz  10yyyyyy  10xxxxxx   000uuuuu zzzzyyyy yyxxxxxx
+**
+**
+** Notes on UTF-16:  (with wwww+1==uuuuu)
+**
+**      Word-0               Word-1          Value
+**  110110ww wwzzzzyy   110111yy yyxxxxxx    000uuuuu zzzzyyyy yyxxxxxx
+**  zzzzyyyy yyxxxxxx                        00000000 zzzzyyyy yyxxxxxx
+**
+**
+** BOM or Byte Order Mark:
+**     0xff 0xfe   little-endian utf-16 follows
+**     0xfe 0xff   big-endian utf-16 follows
+**
+*/
+/* #include "sqliteInt.h" */
+/* #include <assert.h> */
+/* #include "vdbeInt.h" */
+
+#if !defined(SQLITE_AMALGAMATION) && SQLITE_BYTEORDER==0
+/*
+** The following constant value is used by the SQLITE_BIGENDIAN and
+** SQLITE_LITTLEENDIAN macros.
+*/
+SQLITE_PRIVATE const int sqlite3one = 1;
+#endif /* SQLITE_AMALGAMATION && SQLITE_BYTEORDER==0 */
+
+/*
+** This lookup table is used to help decode the first byte of
+** a multi-byte UTF8 character.
+*/
+static const unsigned char sqlite3Utf8Trans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+
+#define WRITE_UTF8(zOut, c) {                          \
+  if( c<0x00080 ){                                     \
+    *zOut++ = (u8)(c&0xFF);                            \
+  }                                                    \
+  else if( c<0x00800 ){                                \
+    *zOut++ = 0xC0 + (u8)((c>>6)&0x1F);                \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+  else if( c<0x10000 ){                                \
+    *zOut++ = 0xE0 + (u8)((c>>12)&0x0F);               \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }else{                                               \
+    *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);             \
+    *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);             \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+}
+
+#define WRITE_UTF16LE(zOut, c) {                                    \
+  if( c<=0xFFFF ){                                                  \
+    *zOut++ = (u8)(c&0x00FF);                                       \
+    *zOut++ = (u8)((c>>8)&0x00FF);                                  \
+  }else{                                                            \
+    *zOut++ = (u8)(((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \
+    *zOut++ = (u8)(0x00D8 + (((c-0x10000)>>18)&0x03));              \
+    *zOut++ = (u8)(c&0x00FF);                                       \
+    *zOut++ = (u8)(0x00DC + ((c>>8)&0x03));                         \
+  }                                                                 \
+}
+
+#define WRITE_UTF16BE(zOut, c) {                                    \
+  if( c<=0xFFFF ){                                                  \
+    *zOut++ = (u8)((c>>8)&0x00FF);                                  \
+    *zOut++ = (u8)(c&0x00FF);                                       \
+  }else{                                                            \
+    *zOut++ = (u8)(0x00D8 + (((c-0x10000)>>18)&0x03));              \
+    *zOut++ = (u8)(((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \
+    *zOut++ = (u8)(0x00DC + ((c>>8)&0x03));                         \
+    *zOut++ = (u8)(c&0x00FF);                                       \
+  }                                                                 \
+}
+
+/*
+** Translate a single UTF-8 character.  Return the unicode value.
+**
+** During translation, assume that the byte that zTerm points
+** is a 0x00.
+**
+** Write a pointer to the next unread byte back into *pzNext.
+**
+** Notes On Invalid UTF-8:
+**
+**  *  This routine never allows a 7-bit character (0x00 through 0x7f) to
+**     be encoded as a multi-byte character.  Any multi-byte character that
+**     attempts to encode a value between 0x00 and 0x7f is rendered as 0xfffd.
+**
+**  *  This routine never allows a UTF16 surrogate value to be encoded.
+**     If a multi-byte character attempts to encode a value between
+**     0xd800 and 0xe000 then it is rendered as 0xfffd.
+**
+**  *  Bytes in the range of 0x80 through 0xbf which occur as the first
+**     byte of a character are interpreted as single-byte characters
+**     and rendered as themselves even though they are technically
+**     invalid characters.
+**
+**  *  This routine accepts over-length UTF8 encodings
+**     for unicode values 0x80 and greater.  It does not change over-length
+**     encodings to 0xfffd as some systems recommend.
+*/
+#define READ_UTF8(zIn, zTerm, c)                           \
+  c = *(zIn++);                                            \
+  if( c>=0xc0 ){                                           \
+    c = sqlite3Utf8Trans1[c-0xc0];                         \
+    while( zIn<zTerm && (*zIn & 0xc0)==0x80 ){             \
+      c = (c<<6) + (0x3f & *(zIn++));                      \
+    }                                                      \
+    if( c<0x80                                             \
+        || (c&0xFFFFF800)==0xD800                          \
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }        \
+  }
+SQLITE_PRIVATE u32 sqlite3Utf8Read(
+  const unsigned char **pz    /* Pointer to string from which to read char */
+){
+  unsigned int c;
+
+  /* Same as READ_UTF8() above but without the zTerm parameter.
+  ** For this routine, we assume the UTF8 string is always zero-terminated.
+  */
+  c = *((*pz)++);
+  if( c>=0xc0 ){
+    c = sqlite3Utf8Trans1[c-0xc0];
+    while( (*(*pz) & 0xc0)==0x80 ){
+      c = (c<<6) + (0x3f & *((*pz)++));
+    }
+    if( c<0x80
+        || (c&0xFFFFF800)==0xD800
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }
+  }
+  return c;
+}
+
+/*
+** Read a single UTF8 character out of buffer z[], but reading no
+** more than n characters from the buffer.  z[] is not zero-terminated.
+**
+** Return the number of bytes used to construct the character.
+**
+** Invalid UTF8 might generate a strange result.  No effort is made
+** to detect invalid UTF8.
+**
+** At most 4 bytes will be read out of z[].  The return value will always
+** be between 1 and 4.
+*/
+SQLITE_PRIVATE int sqlite3Utf8ReadLimited(
+  const u8 *z,
+  int n,
+  u32 *piOut
+){
+  u32 c;
+  int i = 1;
+  assert( n>0 );
+  c = z[0];
+  if( c>=0xc0 ){
+    c = sqlite3Utf8Trans1[c-0xc0];
+    if( n>4 ) n = 4;
+    while( i<n && (z[i] & 0xc0)==0x80 ){
+      c = (c<<6) + (0x3f & z[i]);
+      i++;
+    }
+  }
+  *piOut = c;
+  return i;
+}
+
+
+/*
+** If the TRANSLATE_TRACE macro is defined, the value of each Mem is
+** printed on stderr on the way into and out of sqlite3VdbeMemTranslate().
+*/
+/* #define TRANSLATE_TRACE 1 */
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** This routine transforms the internal text encoding used by pMem to
+** desiredEnc. It is an error if the string is already of the desired
+** encoding, or if *pMem does not contain a string value.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){
+  sqlite3_int64 len;          /* Maximum length of output string in bytes */
+  unsigned char *zOut;        /* Output buffer */
+  unsigned char *zIn;         /* Input iterator */
+  unsigned char *zTerm;       /* End of input */
+  unsigned char *z;           /* Output iterator */
+  unsigned int c;
+
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( pMem->flags&MEM_Str );
+  assert( pMem->enc!=desiredEnc );
+  assert( pMem->enc!=0 );
+  assert( pMem->n>=0 );
+
+#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
+  {
+    StrAccum acc;
+    char zBuf[1000];
+    sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+    sqlite3VdbeMemPrettyPrint(pMem, &acc);
+    fprintf(stderr, "INPUT:  %s\n", sqlite3StrAccumFinish(&acc));
+  }
+#endif
+
+  /* If the translation is between UTF-16 little and big endian, then
+  ** all that is required is to swap the byte order. This case is handled
+  ** differently from the others.
+  */
+  if( pMem->enc!=SQLITE_UTF8 && desiredEnc!=SQLITE_UTF8 ){
+    u8 temp;
+    int rc;
+    rc = sqlite3VdbeMemMakeWriteable(pMem);
+    if( rc!=SQLITE_OK ){
+      assert( rc==SQLITE_NOMEM );
+      return SQLITE_NOMEM_BKPT;
+    }
+    zIn = (u8*)pMem->z;
+    zTerm = &zIn[pMem->n&~1];
+    while( zIn<zTerm ){
+      temp = *zIn;
+      *zIn = *(zIn+1);
+      zIn++;
+      *zIn++ = temp;
+    }
+    pMem->enc = desiredEnc;
+    goto translate_out;
+  }
+
+  /* Set len to the maximum number of bytes required in the output buffer. */
+  if( desiredEnc==SQLITE_UTF8 ){
+    /* When converting from UTF-16, the maximum growth results from
+    ** translating a 2-byte character to a 4-byte UTF-8 character.
+    ** A single byte is required for the output string
+    ** nul-terminator.
+    */
+    pMem->n &= ~1;
+    len = 2 * (sqlite3_int64)pMem->n + 1;
+  }else{
+    /* When converting from UTF-8 to UTF-16 the maximum growth is caused
+    ** when a 1-byte UTF-8 character is translated into a 2-byte UTF-16
+    ** character. Two bytes are required in the output buffer for the
+    ** nul-terminator.
+    */
+    len = 2 * (sqlite3_int64)pMem->n + 2;
+  }
+
+  /* Set zIn to point at the start of the input buffer and zTerm to point 1
+  ** byte past the end.
+  **
+  ** Variable zOut is set to point at the output buffer, space obtained
+  ** from sqlite3_malloc().
+  */
+  zIn = (u8*)pMem->z;
+  zTerm = &zIn[pMem->n];
+  zOut = sqlite3DbMallocRaw(pMem->db, len);
+  if( !zOut ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  z = zOut;
+
+  if( pMem->enc==SQLITE_UTF8 ){
+    if( desiredEnc==SQLITE_UTF16LE ){
+      /* UTF-8 -> UTF-16 Little-endian */
+      while( zIn<zTerm ){
+        READ_UTF8(zIn, zTerm, c);
+        WRITE_UTF16LE(z, c);
+      }
+    }else{
+      assert( desiredEnc==SQLITE_UTF16BE );
+      /* UTF-8 -> UTF-16 Big-endian */
+      while( zIn<zTerm ){
+        READ_UTF8(zIn, zTerm, c);
+        WRITE_UTF16BE(z, c);
+      }
+    }
+    pMem->n = (int)(z - zOut);
+    *z++ = 0;
+  }else{
+    assert( desiredEnc==SQLITE_UTF8 );
+    if( pMem->enc==SQLITE_UTF16LE ){
+      /* UTF-16 Little-endian -> UTF-8 */
+      while( zIn<zTerm ){
+        c = *(zIn++);
+        c += (*(zIn++))<<8;
+        if( c>=0xd800 && c<0xe000 ){
+#ifdef SQLITE_REPLACE_INVALID_UTF
+          if( c>=0xdc00 || zIn>=zTerm ){
+            c = 0xfffd;
+          }else{
+            int c2 = *(zIn++);
+            c2 += (*(zIn++))<<8;
+            if( c2<0xdc00 || c2>=0xe000 ){
+              zIn -= 2;
+              c = 0xfffd;
+            }else{
+              c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
+            }
+          }
+#else
+          if( zIn<zTerm ){
+            int c2 = (*zIn++);
+            c2 += ((*zIn++)<<8);
+            c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);
+          }
+#endif
+        }
+        WRITE_UTF8(z, c);
+      }
+    }else{
+      /* UTF-16 Big-endian -> UTF-8 */
+      while( zIn<zTerm ){
+        c = (*(zIn++))<<8;
+        c += *(zIn++);
+        if( c>=0xd800 && c<0xe000 ){
+#ifdef SQLITE_REPLACE_INVALID_UTF
+          if( c>=0xdc00 || zIn>=zTerm ){
+            c = 0xfffd;
+          }else{
+            int c2 = (*(zIn++))<<8;
+            c2 += *(zIn++);
+            if( c2<0xdc00 || c2>=0xe000 ){
+              zIn -= 2;
+              c = 0xfffd;
+            }else{
+              c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
+            }
+          }
+#else
+          if( zIn<zTerm ){
+            int c2 = ((*zIn++)<<8);
+            c2 += (*zIn++);
+            c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);
+          }
+#endif
+        }
+        WRITE_UTF8(z, c);
+      }
+    }
+    pMem->n = (int)(z - zOut);
+  }
+  *z = 0;
+  assert( (pMem->n+(desiredEnc==SQLITE_UTF8?1:2))<=len );
+
+  c = MEM_Str|MEM_Term|(pMem->flags&(MEM_AffMask|MEM_Subtype));
+  sqlite3VdbeMemRelease(pMem);
+  pMem->flags = c;
+  pMem->enc = desiredEnc;
+  pMem->z = (char*)zOut;
+  pMem->zMalloc = pMem->z;
+  pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->z);
+
+translate_out:
+#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
+  {
+    StrAccum acc;
+    char zBuf[1000];
+    sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+    sqlite3VdbeMemPrettyPrint(pMem, &acc);
+    fprintf(stderr, "OUTPUT: %s\n", sqlite3StrAccumFinish(&acc));
+  }
+#endif
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** This routine checks for a byte-order mark at the beginning of the
+** UTF-16 string stored in *pMem. If one is present, it is removed and
+** the encoding of the Mem adjusted. This routine does not do any
+** byte-swapping, it just sets Mem.enc appropriately.
+**
+** The allocation (static, dynamic etc.) and encoding of the Mem may be
+** changed by this function.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemHandleBom(Mem *pMem){
+  int rc = SQLITE_OK;
+  u8 bom = 0;
+
+  assert( pMem->n>=0 );
+  if( pMem->n>1 ){
+    u8 b1 = *(u8 *)pMem->z;
+    u8 b2 = *(((u8 *)pMem->z) + 1);
+    if( b1==0xFE && b2==0xFF ){
+      bom = SQLITE_UTF16BE;
+    }
+    if( b1==0xFF && b2==0xFE ){
+      bom = SQLITE_UTF16LE;
+    }
+  }
+
+  if( bom ){
+    rc = sqlite3VdbeMemMakeWriteable(pMem);
+    if( rc==SQLITE_OK ){
+      pMem->n -= 2;
+      memmove(pMem->z, &pMem->z[2], pMem->n);
+      pMem->z[pMem->n] = '\0';
+      pMem->z[pMem->n+1] = '\0';
+      pMem->flags |= MEM_Term;
+      pMem->enc = bom;
+    }
+  }
+  return rc;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** pZ is a UTF-8 encoded unicode string. If nByte is less than zero,
+** return the number of unicode characters in pZ up to (but not including)
+** the first 0x00 byte. If nByte is not less than zero, return the
+** number of unicode characters in the first nByte of pZ (or up to
+** the first 0x00, whichever comes first).
+*/
+SQLITE_PRIVATE int sqlite3Utf8CharLen(const char *zIn, int nByte){
+  int r = 0;
+  const u8 *z = (const u8*)zIn;
+  const u8 *zTerm;
+  if( nByte>=0 ){
+    zTerm = &z[nByte];
+  }else{
+    zTerm = (const u8*)(-1);
+  }
+  assert( z<=zTerm );
+  while( *z!=0 && z<zTerm ){
+    SQLITE_SKIP_UTF8(z);
+    r++;
+  }
+  return r;
+}
+
+/* This test function is not currently used by the automated test-suite.
+** Hence it is only available in debug builds.
+*/
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+/*
+** Translate UTF-8 to UTF-8.
+**
+** This has the effect of making sure that the string is well-formed
+** UTF-8.  Miscoded characters are removed.
+**
+** The translation is done in-place and aborted if the output
+** overruns the input.
+*/
+SQLITE_PRIVATE int sqlite3Utf8To8(unsigned char *zIn){
+  unsigned char *zOut = zIn;
+  unsigned char *zStart = zIn;
+  u32 c;
+
+  while( zIn[0] && zOut<=zIn ){
+    c = sqlite3Utf8Read((const u8**)&zIn);
+    if( c!=0xfffd ){
+      WRITE_UTF8(zOut, c);
+    }
+  }
+  *zOut = 0;
+  return (int)(zOut - zStart);
+}
+#endif
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Convert a UTF-16 string in the native encoding into a UTF-8 string.
+** Memory to hold the UTF-8 string is obtained from sqlite3_malloc and must
+** be freed by the calling function.
+**
+** NULL is returned if there is an allocation error.
+*/
+SQLITE_PRIVATE char *sqlite3Utf16to8(sqlite3 *db, const void *z, int nByte, u8 enc){
+  Mem m;
+  memset(&m, 0, sizeof(m));
+  m.db = db;
+  sqlite3VdbeMemSetStr(&m, z, nByte, enc, SQLITE_STATIC);
+  sqlite3VdbeChangeEncoding(&m, SQLITE_UTF8);
+  if( db->mallocFailed ){
+    sqlite3VdbeMemRelease(&m);
+    m.z = 0;
+  }
+  assert( (m.flags & MEM_Term)!=0 || db->mallocFailed );
+  assert( (m.flags & MEM_Str)!=0 || db->mallocFailed );
+  assert( m.z || db->mallocFailed );
+  return m.z;
+}
+
+/*
+** zIn is a UTF-16 encoded unicode string at least nByte bytes long.
+** Return the number of bytes in the first nChar unicode characters
+** in pZ.  nChar must be non-negative.  Surrogate pairs count as a single
+** character.
+*/
+SQLITE_PRIVATE int sqlite3Utf16ByteLen(const void *zIn, int nByte, int nChar){
+  int c;
+  unsigned char const *z = zIn;
+  unsigned char const *zEnd = &z[nByte-1];
+  int n = 0;
+
+  if( SQLITE_UTF16NATIVE==SQLITE_UTF16LE ) z++;
+  while( n<nChar && ALWAYS(z<=zEnd) ){
+    c = z[0];
+    z += 2;
+    if( c>=0xd8 && c<0xdc && z<=zEnd && z[0]>=0xdc && z[0]<0xe0 ) z += 2;
+    n++;
+  }
+  return (int)(z-(unsigned char const *)zIn)
+              - (SQLITE_UTF16NATIVE==SQLITE_UTF16LE);
+}
+
+#if defined(SQLITE_TEST)
+/*
+** This routine is called from the TCL test function "translate_selftest".
+** It checks that the primitives for serializing and deserializing
+** characters in each encoding are inverses of each other.
+*/
+SQLITE_PRIVATE void sqlite3UtfSelfTest(void){
+  unsigned int i, t;
+  unsigned char zBuf[20];
+  unsigned char *z;
+  int n;
+  unsigned int c;
+
+  for(i=0; i<0x00110000; i++){
+    z = zBuf;
+    WRITE_UTF8(z, i);
+    n = (int)(z-zBuf);
+    assert( n>0 && n<=4 );
+    z[0] = 0;
+    z = zBuf;
+    c = sqlite3Utf8Read((const u8**)&z);
+    t = i;
+    if( i>=0xD800 && i<=0xDFFF ) t = 0xFFFD;
+    if( (i&0xFFFFFFFE)==0xFFFE ) t = 0xFFFD;
+    assert( c==t );
+    assert( (z-zBuf)==n );
+  }
+}
+#endif /* SQLITE_TEST */
+#endif /* SQLITE_OMIT_UTF16 */
+
+/************** End of utf.c *************************************************/
+/************** Begin file util.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Utility functions used throughout sqlite.
+**
+** This file contains functions for allocating memory, comparing
+** strings, and stuff like that.
+**
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdarg.h> */
+#ifndef SQLITE_OMIT_FLOATING_POINT
+#include <math.h>
+#endif
+
+/*
+** Calls to sqlite3FaultSim() are used to simulate a failure during testing,
+** or to bypass normal error detection during testing in order to let
+** execute proceed further downstream.
+**
+** In deployment, sqlite3FaultSim() *always* return SQLITE_OK (0).  The
+** sqlite3FaultSim() function only returns non-zero during testing.
+**
+** During testing, if the test harness has set a fault-sim callback using
+** a call to sqlite3_test_control(SQLITE_TESTCTRL_FAULT_INSTALL), then
+** each call to sqlite3FaultSim() is relayed to that application-supplied
+** callback and the integer return value form the application-supplied
+** callback is returned by sqlite3FaultSim().
+**
+** The integer argument to sqlite3FaultSim() is a code to identify which
+** sqlite3FaultSim() instance is being invoked. Each call to sqlite3FaultSim()
+** should have a unique code.  To prevent legacy testing applications from
+** breaking, the codes should not be changed or reused.
+*/
+#ifndef SQLITE_UNTESTABLE
+SQLITE_PRIVATE int sqlite3FaultSim(int iTest){
+  int (*xCallback)(int) = sqlite3GlobalConfig.xTestCallback;
+  return xCallback ? xCallback(iTest) : SQLITE_OK;
+}
+#endif
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Return true if the floating point value is Not a Number (NaN).
+**
+** Use the math library isnan() function if compiled with SQLITE_HAVE_ISNAN.
+** Otherwise, we have our own implementation that works on most systems.
+*/
+SQLITE_PRIVATE int sqlite3IsNaN(double x){
+  int rc;   /* The value return */
+#if !SQLITE_HAVE_ISNAN && !HAVE_ISNAN
+  u64 y;
+  memcpy(&y,&x,sizeof(y));
+  rc = IsNaN(y);
+#else
+  rc = isnan(x);
+#endif /* HAVE_ISNAN */
+  testcase( rc );
+  return rc;
+}
+#endif /* SQLITE_OMIT_FLOATING_POINT */
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Return true if the floating point value is NaN or +Inf or -Inf.
+*/
+SQLITE_PRIVATE int sqlite3IsOverflow(double x){
+  int rc;   /* The value return */
+  u64 y;
+  memcpy(&y,&x,sizeof(y));
+  rc = IsOvfl(y);
+  return rc;
+}
+#endif /* SQLITE_OMIT_FLOATING_POINT */
+
+/*
+** Compute a string length that is limited to what can be stored in
+** lower 30 bits of a 32-bit signed integer.
+**
+** The value returned will never be negative.  Nor will it ever be greater
+** than the actual length of the string.  For very long strings (greater
+** than 1GiB) the value returned might be less than the true string length.
+*/
+SQLITE_PRIVATE int sqlite3Strlen30(const char *z){
+  if( z==0 ) return 0;
+  return 0x3fffffff & (int)strlen(z);
+}
+
+/*
+** Return the declared type of a column.  Or return zDflt if the column
+** has no declared type.
+**
+** The column type is an extra string stored after the zero-terminator on
+** the column name if and only if the COLFLAG_HASTYPE flag is set.
+*/
+SQLITE_PRIVATE char *sqlite3ColumnType(Column *pCol, char *zDflt){
+  if( pCol->colFlags & COLFLAG_HASTYPE ){
+    return pCol->zCnName + strlen(pCol->zCnName) + 1;
+  }else if( pCol->eCType ){
+    assert( pCol->eCType<=SQLITE_N_STDTYPE );
+    return (char*)sqlite3StdType[pCol->eCType-1];
+  }else{
+    return zDflt;
+  }
+}
+
+/*
+** Helper function for sqlite3Error() - called rarely.  Broken out into
+** a separate routine to avoid unnecessary register saves on entry to
+** sqlite3Error().
+*/
+static SQLITE_NOINLINE void  sqlite3ErrorFinish(sqlite3 *db, int err_code){
+  if( db->pErr ) sqlite3ValueSetNull(db->pErr);
+  sqlite3SystemError(db, err_code);
+}
+
+/*
+** Set the current error code to err_code and clear any prior error message.
+** Also set iSysErrno (by calling sqlite3System) if the err_code indicates
+** that would be appropriate.
+*/
+SQLITE_PRIVATE void sqlite3Error(sqlite3 *db, int err_code){
+  assert( db!=0 );
+  db->errCode = err_code;
+  if( err_code || db->pErr ){
+    sqlite3ErrorFinish(db, err_code);
+  }else{
+    db->errByteOffset = -1;
+  }
+}
+
+/*
+** The equivalent of sqlite3Error(db, SQLITE_OK).  Clear the error state
+** and error message.
+*/
+SQLITE_PRIVATE void sqlite3ErrorClear(sqlite3 *db){
+  assert( db!=0 );
+  db->errCode = SQLITE_OK;
+  db->errByteOffset = -1;
+  if( db->pErr ) sqlite3ValueSetNull(db->pErr);
+}
+
+/*
+** Load the sqlite3.iSysErrno field if that is an appropriate thing
+** to do based on the SQLite error code in rc.
+*/
+SQLITE_PRIVATE void sqlite3SystemError(sqlite3 *db, int rc){
+  if( rc==SQLITE_IOERR_NOMEM ) return;
+#if defined(SQLITE_USE_SEH) && !defined(SQLITE_OMIT_WAL)
+  if( rc==SQLITE_IOERR_IN_PAGE ){
+    int ii;
+    int iErr;
+    sqlite3BtreeEnterAll(db);
+    for(ii=0; ii<db->nDb; ii++){
+      if( db->aDb[ii].pBt ){
+        iErr = sqlite3PagerWalSystemErrno(sqlite3BtreePager(db->aDb[ii].pBt));
+        if( iErr ){
+          db->iSysErrno = iErr;
+        }
+      }
+    }
+    sqlite3BtreeLeaveAll(db);
+    return;
+  }
+#endif
+  rc &= 0xff;
+  if( rc==SQLITE_CANTOPEN || rc==SQLITE_IOERR ){
+    db->iSysErrno = sqlite3OsGetLastError(db->pVfs);
+  }
+}
+
+/*
+** Set the most recent error code and error string for the sqlite
+** handle "db". The error code is set to "err_code".
+**
+** If it is not NULL, string zFormat specifies the format of the
+** error string.  zFormat and any string tokens that follow it are
+** assumed to be encoded in UTF-8.
+**
+** To clear the most recent error for sqlite handle "db", sqlite3Error
+** should be called with err_code set to SQLITE_OK and zFormat set
+** to NULL.
+*/
+SQLITE_PRIVATE void sqlite3ErrorWithMsg(sqlite3 *db, int err_code, const char *zFormat, ...){
+  assert( db!=0 );
+  db->errCode = err_code;
+  sqlite3SystemError(db, err_code);
+  if( zFormat==0 ){
+    sqlite3Error(db, err_code);
+  }else if( db->pErr || (db->pErr = sqlite3ValueNew(db))!=0 ){
+    char *z;
+    va_list ap;
+    va_start(ap, zFormat);
+    z = sqlite3VMPrintf(db, zFormat, ap);
+    va_end(ap);
+    sqlite3ValueSetStr(db->pErr, -1, z, SQLITE_UTF8, SQLITE_DYNAMIC);
+  }
+}
+
+/*
+** Check for interrupts and invoke progress callback.
+*/
+SQLITE_PRIVATE void sqlite3ProgressCheck(Parse *p){
+  sqlite3 *db = p->db;
+  if( AtomicLoad(&db->u1.isInterrupted) ){
+    p->nErr++;
+    p->rc = SQLITE_INTERRUPT;
+  }
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  if( db->xProgress ){
+    if( p->rc==SQLITE_INTERRUPT ){
+      p->nProgressSteps = 0;
+    }else if( (++p->nProgressSteps)>=db->nProgressOps ){
+      if( db->xProgress(db->pProgressArg) ){
+        p->nErr++;
+        p->rc = SQLITE_INTERRUPT;
+      }
+      p->nProgressSteps = 0;
+    }
+  }
+#endif
+}
+
+/*
+** Add an error message to pParse->zErrMsg and increment pParse->nErr.
+**
+** This function should be used to report any error that occurs while
+** compiling an SQL statement (i.e. within sqlite3_prepare()). The
+** last thing the sqlite3_prepare() function does is copy the error
+** stored by this function into the database handle using sqlite3Error().
+** Functions sqlite3Error() or sqlite3ErrorWithMsg() should be used
+** during statement execution (sqlite3_step() etc.).
+*/
+SQLITE_PRIVATE void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
+  char *zMsg;
+  va_list ap;
+  sqlite3 *db = pParse->db;
+  assert( db!=0 );
+  assert( db->pParse==pParse || db->pParse->pToplevel==pParse );
+  db->errByteOffset = -2;
+  va_start(ap, zFormat);
+  zMsg = sqlite3VMPrintf(db, zFormat, ap);
+  va_end(ap);
+  if( db->errByteOffset<-1 ) db->errByteOffset = -1;
+  if( db->suppressErr ){
+    sqlite3DbFree(db, zMsg);
+    if( db->mallocFailed ){
+      pParse->nErr++;
+      pParse->rc = SQLITE_NOMEM;
+    }
+  }else{
+    pParse->nErr++;
+    sqlite3DbFree(db, pParse->zErrMsg);
+    pParse->zErrMsg = zMsg;
+    pParse->rc = SQLITE_ERROR;
+    pParse->pWith = 0;
+  }
+}
+
+/*
+** If database connection db is currently parsing SQL, then transfer
+** error code errCode to that parser if the parser has not already
+** encountered some other kind of error.
+*/
+SQLITE_PRIVATE int sqlite3ErrorToParser(sqlite3 *db, int errCode){
+  Parse *pParse;
+  if( db==0 || (pParse = db->pParse)==0 ) return errCode;
+  pParse->rc = errCode;
+  pParse->nErr++;
+  return errCode;
+}
+
+/*
+** Convert an SQL-style quoted string into a normal string by removing
+** the quote characters.  The conversion is done in-place.  If the
+** input does not begin with a quote character, then this routine
+** is a no-op.
+**
+** The input string must be zero-terminated.  A new zero-terminator
+** is added to the dequoted string.
+**
+** The return value is -1 if no dequoting occurs or the length of the
+** dequoted string, exclusive of the zero terminator, if dequoting does
+** occur.
+**
+** 2002-02-14: This routine is extended to remove MS-Access style
+** brackets from around identifiers.  For example:  "[a-b-c]" becomes
+** "a-b-c".
+*/
+SQLITE_PRIVATE void sqlite3Dequote(char *z){
+  char quote;
+  int i, j;
+  if( z==0 ) return;
+  quote = z[0];
+  if( !sqlite3Isquote(quote) ) return;
+  if( quote=='[' ) quote = ']';
+  for(i=1, j=0;; i++){
+    assert( z[i] );
+    if( z[i]==quote ){
+      if( z[i+1]==quote ){
+        z[j++] = quote;
+        i++;
+      }else{
+        break;
+      }
+    }else{
+      z[j++] = z[i];
+    }
+  }
+  z[j] = 0;
+}
+SQLITE_PRIVATE void sqlite3DequoteExpr(Expr *p){
+  assert( !ExprHasProperty(p, EP_IntValue) );
+  assert( sqlite3Isquote(p->u.zToken[0]) );
+  p->flags |= p->u.zToken[0]=='"' ? EP_Quoted|EP_DblQuoted : EP_Quoted;
+  sqlite3Dequote(p->u.zToken);
+}
+
+/*
+** Expression p is a QNUMBER (quoted number). Dequote the value in p->u.zToken
+** and set the type to INTEGER or FLOAT. "Quoted" integers or floats are those
+** that contain '_' characters that must be removed before further processing.
+*/
+SQLITE_PRIVATE void sqlite3DequoteNumber(Parse *pParse, Expr *p){
+  assert( p!=0 || pParse->db->mallocFailed );
+  if( p ){
+    const char *pIn = p->u.zToken;
+    char *pOut = p->u.zToken;
+    int bHex = (pIn[0]=='0' && (pIn[1]=='x' || pIn[1]=='X'));
+    int iValue;
+    assert( p->op==TK_QNUMBER );
+    p->op = TK_INTEGER;
+    do {
+      if( *pIn!=SQLITE_DIGIT_SEPARATOR ){
+        *pOut++ = *pIn;
+        if( *pIn=='e' || *pIn=='E' || *pIn=='.' ) p->op = TK_FLOAT;
+      }else{
+        if( (bHex==0 && (!sqlite3Isdigit(pIn[-1]) || !sqlite3Isdigit(pIn[1])))
+         || (bHex==1 && (!sqlite3Isxdigit(pIn[-1]) || !sqlite3Isxdigit(pIn[1])))
+        ){
+          sqlite3ErrorMsg(pParse, "unrecognized token: \"%s\"", p->u.zToken);
+        }
+      }
+    }while( *pIn++ );
+    if( bHex ) p->op = TK_INTEGER;
+
+    /* tag-20240227-a: If after dequoting, the number is an integer that
+    ** fits in 32 bits, then it must be converted into EP_IntValue.  Other
+    ** parts of the code expect this.  See also tag-20240227-b. */
+    if( p->op==TK_INTEGER && sqlite3GetInt32(p->u.zToken, &iValue) ){
+      p->u.iValue = iValue;
+      p->flags |= EP_IntValue;
+    }
+  }
+}
+
+/*
+** If the input token p is quoted, try to adjust the token to remove
+** the quotes.  This is not always possible:
+**
+**     "abc"     ->   abc
+**     "ab""cd"  ->   (not possible because of the interior "")
+**
+** Remove the quotes if possible.  This is a optimization.  The overall
+** system should still return the correct answer even if this routine
+** is always a no-op.
+*/
+SQLITE_PRIVATE void sqlite3DequoteToken(Token *p){
+  unsigned int i;
+  if( p->n<2 ) return;
+  if( !sqlite3Isquote(p->z[0]) ) return;
+  for(i=1; i<p->n-1; i++){
+    if( sqlite3Isquote(p->z[i]) ) return;
+  }
+  p->n -= 2;
+  p->z++;
+}
+
+/*
+** Generate a Token object from a string
+*/
+SQLITE_PRIVATE void sqlite3TokenInit(Token *p, char *z){
+  p->z = z;
+  p->n = sqlite3Strlen30(z);
+}
+
+/* Convenient short-hand */
+#define UpperToLower sqlite3UpperToLower
+
+/*
+** Some systems have stricmp().  Others have strcasecmp().  Because
+** there is no consistency, we will define our own.
+**
+** IMPLEMENTATION-OF: R-30243-02494 The sqlite3_stricmp() and
+** sqlite3_strnicmp() APIs allow applications and extensions to compare
+** the contents of two buffers containing UTF-8 strings in a
+** case-independent fashion, using the same definition of "case
+** independence" that SQLite uses internally when comparing identifiers.
+*/
+SQLITE_API int sqlite3_stricmp(const char *zLeft, const char *zRight){
+  if( zLeft==0 ){
+    return zRight ? -1 : 0;
+  }else if( zRight==0 ){
+    return 1;
+  }
+  return sqlite3StrICmp(zLeft, zRight);
+}
+SQLITE_PRIVATE int sqlite3StrICmp(const char *zLeft, const char *zRight){
+  unsigned char *a, *b;
+  int c, x;
+  a = (unsigned char *)zLeft;
+  b = (unsigned char *)zRight;
+  for(;;){
+    c = *a;
+    x = *b;
+    if( c==x ){
+      if( c==0 ) break;
+    }else{
+      c = (int)UpperToLower[c] - (int)UpperToLower[x];
+      if( c ) break;
+    }
+    a++;
+    b++;
+  }
+  return c;
+}
+SQLITE_API int sqlite3_strnicmp(const char *zLeft, const char *zRight, int N){
+  register unsigned char *a, *b;
+  if( zLeft==0 ){
+    return zRight ? -1 : 0;
+  }else if( zRight==0 ){
+    return 1;
+  }
+  a = (unsigned char *)zLeft;
+  b = (unsigned char *)zRight;
+  while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
+  return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
+}
+
+/*
+** Compute an 8-bit hash on a string that is insensitive to case differences
+*/
+SQLITE_PRIVATE u8 sqlite3StrIHash(const char *z){
+  u8 h = 0;
+  if( z==0 ) return 0;
+  while( z[0] ){
+    h += UpperToLower[(unsigned char)z[0]];
+    z++;
+  }
+  return h;
+}
+
+/* Double-Double multiplication.  (x[0],x[1]) *= (y,yy)
+**
+** Reference:
+**   T. J. Dekker, "A Floating-Point Technique for Extending the
+**   Available Precision".  1971-07-26.
+*/
+static void dekkerMul2(volatile double *x, double y, double yy){
+  /*
+  ** The "volatile" keywords on parameter x[] and on local variables
+  ** below are needed force intermediate results to be truncated to
+  ** binary64 rather than be carried around in an extended-precision
+  ** format.  The truncation is necessary for the Dekker algorithm to
+  ** work.  Intel x86 floating point might omit the truncation without
+  ** the use of volatile.
+  */
+  volatile double tx, ty, p, q, c, cc;
+  double hx, hy;
+  u64 m;
+  memcpy(&m, (void*)&x[0], 8);
+  m &= 0xfffffffffc000000LL;
+  memcpy(&hx, &m, 8);
+  tx = x[0] - hx;
+  memcpy(&m, &y, 8);
+  m &= 0xfffffffffc000000LL;
+  memcpy(&hy, &m, 8);
+  ty = y - hy;
+  p = hx*hy;
+  q = hx*ty + tx*hy;
+  c = p+q;
+  cc = p - c + q + tx*ty;
+  cc = x[0]*yy + x[1]*y + cc;
+  x[0] = c + cc;
+  x[1] = c - x[0];
+  x[1] += cc;
+}
+
+/*
+** The string z[] is an text representation of a real number.
+** Convert this string to a double and write it into *pResult.
+**
+** The string z[] is length bytes in length (bytes, not characters) and
+** uses the encoding enc.  The string is not necessarily zero-terminated.
+**
+** Return TRUE if the result is a valid real number (or integer) and FALSE
+** if the string is empty or contains extraneous text.  More specifically
+** return
+**      1          =>  The input string is a pure integer
+**      2 or more  =>  The input has a decimal point or eNNN clause
+**      0 or less  =>  The input string is not a valid number
+**     -1          =>  Not a valid number, but has a valid prefix which
+**                     includes a decimal point and/or an eNNN clause
+**
+** Valid numbers are in one of these formats:
+**
+**    [+-]digits[E[+-]digits]
+**    [+-]digits.[digits][E[+-]digits]
+**    [+-].digits[E[+-]digits]
+**
+** Leading and trailing whitespace is ignored for the purpose of determining
+** validity.
+**
+** If some prefix of the input string is a valid number, this routine
+** returns FALSE but it still converts the prefix and writes the result
+** into *pResult.
+*/
+#if defined(_MSC_VER)
+#pragma warning(disable : 4756)
+#endif
+SQLITE_PRIVATE int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  int incr;
+  const char *zEnd;
+  /* sign * significand * (10 ^ (esign * exponent)) */
+  int sign = 1;    /* sign of significand */
+  u64 s = 0;       /* significand */
+  int d = 0;       /* adjust exponent for shifting decimal point */
+  int esign = 1;   /* sign of exponent */
+  int e = 0;       /* exponent */
+  int eValid = 1;  /* True exponent is either not used or is well-formed */
+  int nDigit = 0;  /* Number of digits processed */
+  int eType = 1;   /* 1: pure integer,  2+: fractional  -1 or less: bad UTF16 */
+  u64 s2;          /* round-tripped significand */
+  double rr[2];
+
+  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
+  *pResult = 0.0;   /* Default return value, in case of an error */
+  if( length==0 ) return 0;
+
+  if( enc==SQLITE_UTF8 ){
+    incr = 1;
+    zEnd = z + length;
+  }else{
+    int i;
+    incr = 2;
+    length &= ~1;
+    assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
+    testcase( enc==SQLITE_UTF16LE );
+    testcase( enc==SQLITE_UTF16BE );
+    for(i=3-enc; i<length && z[i]==0; i+=2){}
+    if( i<length ) eType = -100;
+    zEnd = &z[i^1];
+    z += (enc&1);
+  }
+
+  /* skip leading spaces */
+  while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
+  if( z>=zEnd ) return 0;
+
+  /* get sign of significand */
+  if( *z=='-' ){
+    sign = -1;
+    z+=incr;
+  }else if( *z=='+' ){
+    z+=incr;
+  }
+
+  /* copy max significant digits to significand */
+  while( z<zEnd && sqlite3Isdigit(*z) ){
+    s = s*10 + (*z - '0');
+    z+=incr; nDigit++;
+    if( s>=((LARGEST_UINT64-9)/10) ){
+      /* skip non-significant significand digits
+      ** (increase exponent by d to shift decimal left) */
+      while( z<zEnd && sqlite3Isdigit(*z) ){ z+=incr; d++; }
+    }
+  }
+  if( z>=zEnd ) goto do_atof_calc;
+
+  /* if decimal point is present */
+  if( *z=='.' ){
+    z+=incr;
+    eType++;
+    /* copy digits from after decimal to significand
+    ** (decrease exponent by d to shift decimal right) */
+    while( z<zEnd && sqlite3Isdigit(*z) ){
+      if( s<((LARGEST_UINT64-9)/10) ){
+        s = s*10 + (*z - '0');
+        d--;
+        nDigit++;
+      }
+      z+=incr;
+    }
+  }
+  if( z>=zEnd ) goto do_atof_calc;
+
+  /* if exponent is present */
+  if( *z=='e' || *z=='E' ){
+    z+=incr;
+    eValid = 0;
+    eType++;
+
+    /* This branch is needed to avoid a (harmless) buffer overread.  The
+    ** special comment alerts the mutation tester that the correct answer
+    ** is obtained even if the branch is omitted */
+    if( z>=zEnd ) goto do_atof_calc;              /*PREVENTS-HARMLESS-OVERREAD*/
+
+    /* get sign of exponent */
+    if( *z=='-' ){
+      esign = -1;
+      z+=incr;
+    }else if( *z=='+' ){
+      z+=incr;
+    }
+    /* copy digits to exponent */
+    while( z<zEnd && sqlite3Isdigit(*z) ){
+      e = e<10000 ? (e*10 + (*z - '0')) : 10000;
+      z+=incr;
+      eValid = 1;
+    }
+  }
+
+  /* skip trailing spaces */
+  while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
+
+do_atof_calc:
+  /* Zero is a special case */
+  if( s==0 ){
+    *pResult = sign<0 ? -0.0 : +0.0;
+    goto atof_return;
+  }
+
+  /* adjust exponent by d, and update sign */
+  e = (e*esign) + d;
+
+  /* Try to adjust the exponent to make it smaller */
+  while( e>0 && s<((LARGEST_UINT64-0x7ff)/10) ){
+    s *= 10;
+    e--;
+  }
+  while( e<0 && (s%10)==0 ){
+    s /= 10;
+    e++;
+  }
+
+  rr[0] = (double)s;
+  assert( sizeof(s2)==sizeof(rr[0]) );
+#ifdef SQLITE_DEBUG
+  rr[1] = 18446744073709549568.0;
+  memcpy(&s2, &rr[1], sizeof(s2));
+  assert( s2==0x43efffffffffffffLL );
+#endif
+  /* Largest double that can be safely converted to u64
+  **         vvvvvvvvvvvvvvvvvvvvvv   */
+  if( rr[0]<=18446744073709549568.0 ){
+    s2 = (u64)rr[0];
+    rr[1] = s>=s2 ? (double)(s - s2) : -(double)(s2 - s);
+  }else{
+    rr[1] = 0.0;
+  }
+  assert( rr[1]<=1.0e-10*rr[0] );  /* Equal only when rr[0]==0.0 */
+
+  if( e>0 ){
+    while( e>=100  ){
+      e -= 100;
+      dekkerMul2(rr, 1.0e+100, -1.5902891109759918046e+83);
+    }
+    while( e>=10   ){
+      e -= 10;
+      dekkerMul2(rr, 1.0e+10, 0.0);
+    }
+    while( e>=1    ){
+      e -= 1;
+      dekkerMul2(rr, 1.0e+01, 0.0);
+    }
+  }else{
+    while( e<=-100 ){
+      e += 100;
+      dekkerMul2(rr, 1.0e-100, -1.99918998026028836196e-117);
+    }
+    while( e<=-10  ){
+      e += 10;
+      dekkerMul2(rr, 1.0e-10, -3.6432197315497741579e-27);
+    }
+    while( e<=-1   ){
+      e += 1;
+      dekkerMul2(rr, 1.0e-01, -5.5511151231257827021e-18);
+    }
+  }
+  *pResult = rr[0]+rr[1];
+  if( sqlite3IsNaN(*pResult) ) *pResult = 1e300*1e300;
+  if( sign<0 ) *pResult = -*pResult;
+  assert( !sqlite3IsNaN(*pResult) );
+
+atof_return:
+  /* return true if number and no extra non-whitespace characters after */
+  if( z==zEnd && nDigit>0 && eValid && eType>0 ){
+    return eType;
+  }else if( eType>=2 && (eType==3 || eValid) && nDigit>0 ){
+    return -1;
+  }else{
+    return 0;
+  }
+#else
+  return !sqlite3Atoi64(z, pResult, length, enc);
+#endif /* SQLITE_OMIT_FLOATING_POINT */
+}
+#if defined(_MSC_VER)
+#pragma warning(default : 4756)
+#endif
+
+/*
+** Render an signed 64-bit integer as text.  Store the result in zOut[] and
+** return the length of the string that was stored, in bytes.  The value
+** returned does not include the zero terminator at the end of the output
+** string.
+**
+** The caller must ensure that zOut[] is at least 21 bytes in size.
+*/
+SQLITE_PRIVATE int sqlite3Int64ToText(i64 v, char *zOut){
+  int i;
+  u64 x;
+  char zTemp[22];
+  if( v<0 ){
+    x = (v==SMALLEST_INT64) ? ((u64)1)<<63 : (u64)-v;
+  }else{
+    x = v;
+  }
+  i = sizeof(zTemp)-2;
+  zTemp[sizeof(zTemp)-1] = 0;
+  while( 1 /*exit-by-break*/ ){
+    zTemp[i] = (x%10) + '0';
+    x = x/10;
+    if( x==0 ) break;
+    i--;
+  };
+  if( v<0 ) zTemp[--i] = '-';
+  memcpy(zOut, &zTemp[i], sizeof(zTemp)-i);
+  return sizeof(zTemp)-1-i;
+}
+
+/*
+** Compare the 19-character string zNum against the text representation
+** value 2^63:  9223372036854775808.  Return negative, zero, or positive
+** if zNum is less than, equal to, or greater than the string.
+** Note that zNum must contain exactly 19 characters.
+**
+** Unlike memcmp() this routine is guaranteed to return the difference
+** in the values of the last digit if the only difference is in the
+** last digit.  So, for example,
+**
+**      compare2pow63("9223372036854775800", 1)
+**
+** will return -8.
+*/
+static int compare2pow63(const char *zNum, int incr){
+  int c = 0;
+  int i;
+                    /* 012345678901234567 */
+  const char *pow63 = "922337203685477580";
+  for(i=0; c==0 && i<18; i++){
+    c = (zNum[i*incr]-pow63[i])*10;
+  }
+  if( c==0 ){
+    c = zNum[18*incr] - '8';
+    testcase( c==(-1) );
+    testcase( c==0 );
+    testcase( c==(+1) );
+  }
+  return c;
+}
+
+/*
+** Convert zNum to a 64-bit signed integer.  zNum must be decimal. This
+** routine does *not* accept hexadecimal notation.
+**
+** Returns:
+**
+**    -1    Not even a prefix of the input text looks like an integer
+**     0    Successful transformation.  Fits in a 64-bit signed integer.
+**     1    Excess non-space text after the integer value
+**     2    Integer too large for a 64-bit signed integer or is malformed
+**     3    Special case of 9223372036854775808
+**
+** length is the number of bytes in the string (bytes, not characters).
+** The string is not necessarily zero-terminated.  The encoding is
+** given by enc.
+*/
+SQLITE_PRIVATE int sqlite3Atoi64(const char *zNum, i64 *pNum, int length, u8 enc){
+  int incr;
+  u64 u = 0;
+  int neg = 0; /* assume positive */
+  int i;
+  int c = 0;
+  int nonNum = 0;  /* True if input contains UTF16 with high byte non-zero */
+  int rc;          /* Baseline return code */
+  const char *zStart;
+  const char *zEnd = zNum + length;
+  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
+  if( enc==SQLITE_UTF8 ){
+    incr = 1;
+  }else{
+    incr = 2;
+    length &= ~1;
+    assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
+    for(i=3-enc; i<length && zNum[i]==0; i+=2){}
+    nonNum = i<length;
+    zEnd = &zNum[i^1];
+    zNum += (enc&1);
+  }
+  while( zNum<zEnd && sqlite3Isspace(*zNum) ) zNum+=incr;
+  if( zNum<zEnd ){
+    if( *zNum=='-' ){
+      neg = 1;
+      zNum+=incr;
+    }else if( *zNum=='+' ){
+      zNum+=incr;
+    }
+  }
+  zStart = zNum;
+  while( zNum<zEnd && zNum[0]=='0' ){ zNum+=incr; } /* Skip leading zeros. */
+  for(i=0; &zNum[i]<zEnd && (c=zNum[i])>='0' && c<='9'; i+=incr){
+    u = u*10 + c - '0';
+  }
+  testcase( i==18*incr );
+  testcase( i==19*incr );
+  testcase( i==20*incr );
+  if( u>LARGEST_INT64 ){
+    /* This test and assignment is needed only to suppress UB warnings
+    ** from clang and -fsanitize=undefined.  This test and assignment make
+    ** the code a little larger and slower, and no harm comes from omitting
+    ** them, but we must appease the undefined-behavior pharisees. */
+    *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
+  }else if( neg ){
+    *pNum = -(i64)u;
+  }else{
+    *pNum = (i64)u;
+  }
+  rc = 0;
+  if( i==0 && zStart==zNum ){    /* No digits */
+    rc = -1;
+  }else if( nonNum ){            /* UTF16 with high-order bytes non-zero */
+    rc = 1;
+  }else if( &zNum[i]<zEnd ){     /* Extra bytes at the end */
+    int jj = i;
+    do{
+      if( !sqlite3Isspace(zNum[jj]) ){
+        rc = 1;          /* Extra non-space text after the integer */
+        break;
+      }
+      jj += incr;
+    }while( &zNum[jj]<zEnd );
+  }
+  if( i<19*incr ){
+    /* Less than 19 digits, so we know that it fits in 64 bits */
+    assert( u<=LARGEST_INT64 );
+    return rc;
+  }else{
+    /* zNum is a 19-digit numbers.  Compare it against 9223372036854775808. */
+    c = i>19*incr ? 1 : compare2pow63(zNum, incr);
+    if( c<0 ){
+      /* zNum is less than 9223372036854775808 so it fits */
+      assert( u<=LARGEST_INT64 );
+      return rc;
+    }else{
+      *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
+      if( c>0 ){
+        /* zNum is greater than 9223372036854775808 so it overflows */
+        return 2;
+      }else{
+        /* zNum is exactly 9223372036854775808.  Fits if negative.  The
+        ** special case 2 overflow if positive */
+        assert( u-1==LARGEST_INT64 );
+        return neg ? rc : 3;
+      }
+    }
+  }
+}
+
+/*
+** Transform a UTF-8 integer literal, in either decimal or hexadecimal,
+** into a 64-bit signed integer.  This routine accepts hexadecimal literals,
+** whereas sqlite3Atoi64() does not.
+**
+** Returns:
+**
+**     0    Successful transformation.  Fits in a 64-bit signed integer.
+**     1    Excess text after the integer value
+**     2    Integer too large for a 64-bit signed integer or is malformed
+**     3    Special case of 9223372036854775808
+*/
+SQLITE_PRIVATE int sqlite3DecOrHexToI64(const char *z, i64 *pOut){
+#ifndef SQLITE_OMIT_HEX_INTEGER
+  if( z[0]=='0'
+   && (z[1]=='x' || z[1]=='X')
+  ){
+    u64 u = 0;
+    int i, k;
+    for(i=2; z[i]=='0'; i++){}
+    for(k=i; sqlite3Isxdigit(z[k]); k++){
+      u = u*16 + sqlite3HexToInt(z[k]);
+    }
+    memcpy(pOut, &u, 8);
+    if( k-i>16 ) return 2;
+    if( z[k]!=0 ) return 1;
+    return 0;
+  }else
+#endif /* SQLITE_OMIT_HEX_INTEGER */
+  {
+    int n = (int)(0x3fffffff&strspn(z,"+- \n\t0123456789"));
+    if( z[n] ) n++;
+    return sqlite3Atoi64(z, pOut, n, SQLITE_UTF8);
+  }
+}
+
+/*
+** If zNum represents an integer that will fit in 32-bits, then set
+** *pValue to that integer and return true.  Otherwise return false.
+**
+** This routine accepts both decimal and hexadecimal notation for integers.
+**
+** Any non-numeric characters that following zNum are ignored.
+** This is different from sqlite3Atoi64() which requires the
+** input number to be zero-terminated.
+*/
+SQLITE_PRIVATE int sqlite3GetInt32(const char *zNum, int *pValue){
+  sqlite_int64 v = 0;
+  int i, c;
+  int neg = 0;
+  if( zNum[0]=='-' ){
+    neg = 1;
+    zNum++;
+  }else if( zNum[0]=='+' ){
+    zNum++;
+  }
+#ifndef SQLITE_OMIT_HEX_INTEGER
+  else if( zNum[0]=='0'
+        && (zNum[1]=='x' || zNum[1]=='X')
+        && sqlite3Isxdigit(zNum[2])
+  ){
+    u32 u = 0;
+    zNum += 2;
+    while( zNum[0]=='0' ) zNum++;
+    for(i=0; i<8 && sqlite3Isxdigit(zNum[i]); i++){
+      u = u*16 + sqlite3HexToInt(zNum[i]);
+    }
+    if( (u&0x80000000)==0 && sqlite3Isxdigit(zNum[i])==0 ){
+      memcpy(pValue, &u, 4);
+      return 1;
+    }else{
+      return 0;
+    }
+  }
+#endif
+  if( !sqlite3Isdigit(zNum[0]) ) return 0;
+  while( zNum[0]=='0' ) zNum++;
+  for(i=0; i<11 && (c = zNum[i] - '0')>=0 && c<=9; i++){
+    v = v*10 + c;
+  }
+
+  /* The longest decimal representation of a 32 bit integer is 10 digits:
+  **
+  **             1234567890
+  **     2^31 -> 2147483648
+  */
+  testcase( i==10 );
+  if( i>10 ){
+    return 0;
+  }
+  testcase( v-neg==2147483647 );
+  if( v-neg>2147483647 ){
+    return 0;
+  }
+  if( neg ){
+    v = -v;
+  }
+  *pValue = (int)v;
+  return 1;
+}
+
+/*
+** Return a 32-bit integer value extracted from a string.  If the
+** string is not an integer, just return 0.
+*/
+SQLITE_PRIVATE int sqlite3Atoi(const char *z){
+  int x = 0;
+  sqlite3GetInt32(z, &x);
+  return x;
+}
+
+/*
+** Decode a floating-point value into an approximate decimal
+** representation.
+**
+** If iRound<=0 then round to -iRound significant digits to the
+** the left of the decimal point, or to a maximum of mxRound total
+** significant digits.
+**
+** If iRound>0 round to min(iRound,mxRound) significant digits total.
+**
+** mxRound must be positive.
+**
+** The significant digits of the decimal representation are
+** stored in p->z[] which is a often (but not always) a pointer
+** into the middle of p->zBuf[].  There are p->n significant digits.
+** The p->z[] array is *not* zero-terminated.
+*/
+SQLITE_PRIVATE void sqlite3FpDecode(FpDecode *p, double r, int iRound, int mxRound){
+  int i;
+  u64 v;
+  int e, exp = 0;
+  double rr[2];
+
+  p->isSpecial = 0;
+  p->z = p->zBuf;
+  assert( mxRound>0 );
+
+  /* Convert negative numbers to positive.  Deal with Infinity, 0.0, and
+  ** NaN. */
+  if( r<0.0 ){
+    p->sign = '-';
+    r = -r;
+  }else if( r==0.0 ){
+    p->sign = '+';
+    p->n = 1;
+    p->iDP = 1;
+    p->z = "0";
+    return;
+  }else{
+    p->sign = '+';
+  }
+  memcpy(&v,&r,8);
+  e = v>>52;
+  if( (e&0x7ff)==0x7ff ){
+    p->isSpecial = 1 + (v!=0x7ff0000000000000LL);
+    p->n = 0;
+    p->iDP = 0;
+    return;
+  }
+
+  /* Multiply r by powers of ten until it lands somewhere in between
+  ** 1.0e+19 and 1.0e+17.
+  **
+  ** Use Dekker-style double-double computation to increase the
+  ** precision.
+  **
+  ** The error terms on constants like 1.0e+100 computed using the
+  ** decimal extension, for example as follows:
+  **
+  **   SELECT decimal_exp(decimal_sub('1.0e+100',decimal(1.0e+100)));
+  */
+  rr[0] = r;
+  rr[1] = 0.0;
+  if( rr[0]>9.223372036854774784e+18 ){
+    while( rr[0]>9.223372036854774784e+118 ){
+      exp += 100;
+      dekkerMul2(rr, 1.0e-100, -1.99918998026028836196e-117);
+    }
+    while( rr[0]>9.223372036854774784e+28 ){
+      exp += 10;
+      dekkerMul2(rr, 1.0e-10, -3.6432197315497741579e-27);
+    }
+    while( rr[0]>9.223372036854774784e+18 ){
+      exp += 1;
+      dekkerMul2(rr, 1.0e-01, -5.5511151231257827021e-18);
+    }
+  }else{
+    while( rr[0]<9.223372036854774784e-83  ){
+      exp -= 100;
+      dekkerMul2(rr, 1.0e+100, -1.5902891109759918046e+83);
+    }
+    while( rr[0]<9.223372036854774784e+07  ){
+      exp -= 10;
+      dekkerMul2(rr, 1.0e+10, 0.0);
+    }
+    while( rr[0]<9.22337203685477478e+17  ){
+      exp -= 1;
+      dekkerMul2(rr, 1.0e+01, 0.0);
+    }
+  }
+  v = rr[1]<0.0 ? (u64)rr[0]-(u64)(-rr[1]) : (u64)rr[0]+(u64)rr[1];
+
+  /* Extract significant digits. */
+  i = sizeof(p->zBuf)-1;
+  assert( v>0 );
+  while( v ){  p->zBuf[i--] = (v%10) + '0'; v /= 10; }
+  assert( i>=0 && i<sizeof(p->zBuf)-1 );
+  p->n = sizeof(p->zBuf) - 1 - i;
+  assert( p->n>0 );
+  assert( p->n<sizeof(p->zBuf) );
+  p->iDP = p->n + exp;
+  if( iRound<=0 ){
+    iRound = p->iDP - iRound;
+    if( iRound==0 && p->zBuf[i+1]>='5' ){
+      iRound = 1;
+      p->zBuf[i--] = '0';
+      p->n++;
+      p->iDP++;
+    }
+  }
+  if( iRound>0 && (iRound<p->n || p->n>mxRound) ){
+    char *z = &p->zBuf[i+1];
+    if( iRound>mxRound ) iRound = mxRound;
+    p->n = iRound;
+    if( z[iRound]>='5' ){
+      int j = iRound-1;
+      while( 1 /*exit-by-break*/ ){
+        z[j]++;
+        if( z[j]<='9' ) break;
+        z[j] = '0';
+        if( j==0 ){
+          p->z[i--] = '1';
+          p->n++;
+          p->iDP++;
+          break;
+        }else{
+          j--;
+        }
+      }
+    }
+  }
+  p->z = &p->zBuf[i+1];
+  assert( i+p->n < sizeof(p->zBuf) );
+  while( ALWAYS(p->n>0) && p->z[p->n-1]=='0' ){ p->n--; }
+}
+
+/*
+** Try to convert z into an unsigned 32-bit integer.  Return true on
+** success and false if there is an error.
+**
+** Only decimal notation is accepted.
+*/
+SQLITE_PRIVATE int sqlite3GetUInt32(const char *z, u32 *pI){
+  u64 v = 0;
+  int i;
+  for(i=0; sqlite3Isdigit(z[i]); i++){
+    v = v*10 + z[i] - '0';
+    if( v>4294967296LL ){ *pI = 0; return 0; }
+  }
+  if( i==0 || z[i]!=0 ){ *pI = 0; return 0; }
+  *pI = (u32)v;
+  return 1;
+}
+
+/*
+** The variable-length integer encoding is as follows:
+**
+** KEY:
+**         A = 0xxxxxxx    7 bits of data and one flag bit
+**         B = 1xxxxxxx    7 bits of data and one flag bit
+**         C = xxxxxxxx    8 bits of data
+**
+**  7 bits - A
+** 14 bits - BA
+** 21 bits - BBA
+** 28 bits - BBBA
+** 35 bits - BBBBA
+** 42 bits - BBBBBA
+** 49 bits - BBBBBBA
+** 56 bits - BBBBBBBA
+** 64 bits - BBBBBBBBC
+*/
+
+/*
+** Write a 64-bit variable-length integer to memory starting at p[0].
+** The length of data write will be between 1 and 9 bytes.  The number
+** of bytes written is returned.
+**
+** A variable-length integer consists of the lower 7 bits of each byte
+** for all bytes that have the 8th bit set and one byte with the 8th
+** bit clear.  Except, if we get to the 9th byte, it stores the full
+** 8 bits and is the last byte.
+*/
+static int SQLITE_NOINLINE putVarint64(unsigned char *p, u64 v){
+  int i, j, n;
+  u8 buf[10];
+  if( v & (((u64)0xff000000)<<32) ){
+    p[8] = (u8)v;
+    v >>= 8;
+    for(i=7; i>=0; i--){
+      p[i] = (u8)((v & 0x7f) | 0x80);
+      v >>= 7;
+    }
+    return 9;
+  }
+  n = 0;
+  do{
+    buf[n++] = (u8)((v & 0x7f) | 0x80);
+    v >>= 7;
+  }while( v!=0 );
+  buf[0] &= 0x7f;
+  assert( n<=9 );
+  for(i=0, j=n-1; j>=0; j--, i++){
+    p[i] = buf[j];
+  }
+  return n;
+}
+SQLITE_PRIVATE int sqlite3PutVarint(unsigned char *p, u64 v){
+  if( v<=0x7f ){
+    p[0] = v&0x7f;
+    return 1;
+  }
+  if( v<=0x3fff ){
+    p[0] = ((v>>7)&0x7f)|0x80;
+    p[1] = v&0x7f;
+    return 2;
+  }
+  return putVarint64(p,v);
+}
+
+/*
+** Bitmasks used by sqlite3GetVarint().  These precomputed constants
+** are defined here rather than simply putting the constant expressions
+** inline in order to work around bugs in the RVT compiler.
+**
+** SLOT_2_0     A mask for  (0x7f<<14) | 0x7f
+**
+** SLOT_4_2_0   A mask for  (0x7f<<28) | SLOT_2_0
+*/
+#define SLOT_2_0     0x001fc07f
+#define SLOT_4_2_0   0xf01fc07f
+
+
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read.  The value is stored in *v.
+*/
+SQLITE_PRIVATE u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
+  u32 a,b,s;
+
+  if( ((signed char*)p)[0]>=0 ){
+    *v = *p;
+    return 1;
+  }
+  if( ((signed char*)p)[1]>=0 ){
+    *v = ((u32)(p[0]&0x7f)<<7) | p[1];
+    return 2;
+  }
+
+  /* Verify that constants are precomputed correctly */
+  assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
+  assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
+
+  a = ((u32)p[0])<<14;
+  b = p[1];
+  p += 2;
+  a |= *p;
+  /* a: p0<<14 | p2 (unmasked) */
+  if (!(a&0x80))
+  {
+    a &= SLOT_2_0;
+    b &= 0x7f;
+    b = b<<7;
+    a |= b;
+    *v = a;
+    return 3;
+  }
+
+  /* CSE1 from below */
+  a &= SLOT_2_0;
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<14 | p3 (unmasked) */
+  if (!(b&0x80))
+  {
+    b &= SLOT_2_0;
+    /* moved CSE1 up */
+    /* a &= (0x7f<<14)|(0x7f); */
+    a = a<<7;
+    a |= b;
+    *v = a;
+    return 4;
+  }
+
+  /* a: p0<<14 | p2 (masked) */
+  /* b: p1<<14 | p3 (unmasked) */
+  /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+  /* moved CSE1 up */
+  /* a &= (0x7f<<14)|(0x7f); */
+  b &= SLOT_2_0;
+  s = a;
+  /* s: p0<<14 | p2 (masked) */
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<28 | p2<<14 | p4 (unmasked) */
+  if (!(a&0x80))
+  {
+    /* we can skip these cause they were (effectively) done above
+    ** while calculating s */
+    /* a &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
+    /* b &= (0x7f<<14)|(0x7f); */
+    b = b<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 5;
+  }
+
+  /* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+  s = s<<7;
+  s |= b;
+  /* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<28 | p3<<14 | p5 (unmasked) */
+  if (!(b&0x80))
+  {
+    /* we can skip this cause it was (effectively) done above in calc'ing s */
+    /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
+    a &= SLOT_2_0;
+    a = a<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 6;
+  }
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p2<<28 | p4<<14 | p6 (unmasked) */
+  if (!(a&0x80))
+  {
+    a &= SLOT_4_2_0;
+    b &= SLOT_2_0;
+    b = b<<7;
+    a |= b;
+    s = s>>11;
+    *v = ((u64)s)<<32 | a;
+    return 7;
+  }
+
+  /* CSE2 from below */
+  a &= SLOT_2_0;
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p3<<28 | p5<<14 | p7 (unmasked) */
+  if (!(b&0x80))
+  {
+    b &= SLOT_4_2_0;
+    /* moved CSE2 up */
+    /* a &= (0x7f<<14)|(0x7f); */
+    a = a<<7;
+    a |= b;
+    s = s>>4;
+    *v = ((u64)s)<<32 | a;
+    return 8;
+  }
+
+  p++;
+  a = a<<15;
+  a |= *p;
+  /* a: p4<<29 | p6<<15 | p8 (unmasked) */
+
+  /* moved CSE2 up */
+  /* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
+  b &= SLOT_2_0;
+  b = b<<8;
+  a |= b;
+
+  s = s<<4;
+  b = p[-4];
+  b &= 0x7f;
+  b = b>>3;
+  s |= b;
+
+  *v = ((u64)s)<<32 | a;
+
+  return 9;
+}
+
+/*
+** Read a 32-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read.  The value is stored in *v.
+**
+** If the varint stored in p[0] is larger than can fit in a 32-bit unsigned
+** integer, then set *v to 0xffffffff.
+**
+** A MACRO version, getVarint32, is provided which inlines the
+** single-byte case.  All code should use the MACRO version as
+** this function assumes the single-byte case has already been handled.
+*/
+SQLITE_PRIVATE u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
+  u64 v64;
+  u8 n;
+
+  /* Assume that the single-byte case has already been handled by
+  ** the getVarint32() macro */
+  assert( (p[0] & 0x80)!=0 );
+
+  if( (p[1] & 0x80)==0 ){
+    /* This is the two-byte case */
+    *v = ((p[0]&0x7f)<<7) | p[1];
+    return 2;
+  }
+  if( (p[2] & 0x80)==0 ){
+    /* This is the three-byte case */
+    *v = ((p[0]&0x7f)<<14) | ((p[1]&0x7f)<<7) | p[2];
+    return 3;
+  }
+  /* four or more bytes */
+  n = sqlite3GetVarint(p, &v64);
+  assert( n>3 && n<=9 );
+  if( (v64 & SQLITE_MAX_U32)!=v64 ){
+    *v = 0xffffffff;
+  }else{
+    *v = (u32)v64;
+  }
+  return n;
+}
+
+/*
+** Return the number of bytes that will be needed to store the given
+** 64-bit integer.
+*/
+SQLITE_PRIVATE int sqlite3VarintLen(u64 v){
+  int i;
+  for(i=1; (v >>= 7)!=0; i++){ assert( i<10 ); }
+  return i;
+}
+
+
+/*
+** Read or write a four-byte big-endian integer value.
+*/
+SQLITE_PRIVATE u32 sqlite3Get4byte(const u8 *p){
+#if SQLITE_BYTEORDER==4321
+  u32 x;
+  memcpy(&x,p,4);
+  return x;
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  u32 x;
+  memcpy(&x,p,4);
+  return __builtin_bswap32(x);
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  u32 x;
+  memcpy(&x,p,4);
+  return _byteswap_ulong(x);
+#else
+  testcase( p[0]&0x80 );
+  return ((unsigned)p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
+#endif
+}
+SQLITE_PRIVATE void sqlite3Put4byte(unsigned char *p, u32 v){
+#if SQLITE_BYTEORDER==4321
+  memcpy(p,&v,4);
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  u32 x = __builtin_bswap32(v);
+  memcpy(p,&x,4);
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  u32 x = _byteswap_ulong(v);
+  memcpy(p,&x,4);
+#else
+  p[0] = (u8)(v>>24);
+  p[1] = (u8)(v>>16);
+  p[2] = (u8)(v>>8);
+  p[3] = (u8)v;
+#endif
+}
+
+
+
+/*
+** Translate a single byte of Hex into an integer.
+** This routine only works if h really is a valid hexadecimal
+** character:  0..9a..fA..F
+*/
+SQLITE_PRIVATE u8 sqlite3HexToInt(int h){
+  assert( (h>='0' && h<='9') ||  (h>='a' && h<='f') ||  (h>='A' && h<='F') );
+#ifdef SQLITE_ASCII
+  h += 9*(1&(h>>6));
+#endif
+#ifdef SQLITE_EBCDIC
+  h += 9*(1&~(h>>4));
+#endif
+  return (u8)(h & 0xf);
+}
+
+#if !defined(SQLITE_OMIT_BLOB_LITERAL)
+/*
+** Convert a BLOB literal of the form "x'hhhhhh'" into its binary
+** value.  Return a pointer to its binary value.  Space to hold the
+** binary value has been obtained from malloc and must be freed by
+** the calling routine.
+*/
+SQLITE_PRIVATE void *sqlite3HexToBlob(sqlite3 *db, const char *z, int n){
+  char *zBlob;
+  int i;
+
+  zBlob = (char *)sqlite3DbMallocRawNN(db, n/2 + 1);
+  n--;
+  if( zBlob ){
+    for(i=0; i<n; i+=2){
+      zBlob[i/2] = (sqlite3HexToInt(z[i])<<4) | sqlite3HexToInt(z[i+1]);
+    }
+    zBlob[i/2] = 0;
+  }
+  return zBlob;
+}
+#endif /* !SQLITE_OMIT_BLOB_LITERAL */
+
+/*
+** Log an error that is an API call on a connection pointer that should
+** not have been used.  The "type" of connection pointer is given as the
+** argument.  The zType is a word like "NULL" or "closed" or "invalid".
+*/
+static void logBadConnection(const char *zType){
+  sqlite3_log(SQLITE_MISUSE,
+     "API call with %s database connection pointer",
+     zType
+  );
+}
+
+/*
+** Check to make sure we have a valid db pointer.  This test is not
+** foolproof but it does provide some measure of protection against
+** misuse of the interface such as passing in db pointers that are
+** NULL or which have been previously closed.  If this routine returns
+** 1 it means that the db pointer is valid and 0 if it should not be
+** dereferenced for any reason.  The calling function should invoke
+** SQLITE_MISUSE immediately.
+**
+** sqlite3SafetyCheckOk() requires that the db pointer be valid for
+** use.  sqlite3SafetyCheckSickOrOk() allows a db pointer that failed to
+** open properly and is not fit for general use but which can be
+** used as an argument to sqlite3_errmsg() or sqlite3_close().
+*/
+SQLITE_PRIVATE int sqlite3SafetyCheckOk(sqlite3 *db){
+  u8 eOpenState;
+  if( db==0 ){
+    logBadConnection("NULL");
+    return 0;
+  }
+  eOpenState = db->eOpenState;
+  if( eOpenState!=SQLITE_STATE_OPEN ){
+    if( sqlite3SafetyCheckSickOrOk(db) ){
+      testcase( sqlite3GlobalConfig.xLog!=0 );
+      logBadConnection("unopened");
+    }
+    return 0;
+  }else{
+    return 1;
+  }
+}
+SQLITE_PRIVATE int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
+  u8 eOpenState;
+  eOpenState = db->eOpenState;
+  if( eOpenState!=SQLITE_STATE_SICK &&
+      eOpenState!=SQLITE_STATE_OPEN &&
+      eOpenState!=SQLITE_STATE_BUSY ){
+    testcase( sqlite3GlobalConfig.xLog!=0 );
+    logBadConnection("invalid");
+    return 0;
+  }else{
+    return 1;
+  }
+}
+
+/*
+** Attempt to add, subtract, or multiply the 64-bit signed value iB against
+** the other 64-bit signed integer at *pA and store the result in *pA.
+** Return 0 on success.  Or if the operation would have resulted in an
+** overflow, leave *pA unchanged and return 1.
+*/
+SQLITE_PRIVATE int sqlite3AddInt64(i64 *pA, i64 iB){
+#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
+  return __builtin_add_overflow(*pA, iB, pA);
+#else
+  i64 iA = *pA;
+  testcase( iA==0 ); testcase( iA==1 );
+  testcase( iB==-1 ); testcase( iB==0 );
+  if( iB>=0 ){
+    testcase( iA>0 && LARGEST_INT64 - iA == iB );
+    testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
+    if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
+  }else{
+    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
+    testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
+    if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
+  }
+  *pA += iB;
+  return 0;
+#endif
+}
+SQLITE_PRIVATE int sqlite3SubInt64(i64 *pA, i64 iB){
+#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
+  return __builtin_sub_overflow(*pA, iB, pA);
+#else
+  testcase( iB==SMALLEST_INT64+1 );
+  if( iB==SMALLEST_INT64 ){
+    testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
+    if( (*pA)>=0 ) return 1;
+    *pA -= iB;
+    return 0;
+  }else{
+    return sqlite3AddInt64(pA, -iB);
+  }
+#endif
+}
+SQLITE_PRIVATE int sqlite3MulInt64(i64 *pA, i64 iB){
+#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
+  return __builtin_mul_overflow(*pA, iB, pA);
+#else
+  i64 iA = *pA;
+  if( iB>0 ){
+    if( iA>LARGEST_INT64/iB ) return 1;
+    if( iA<SMALLEST_INT64/iB ) return 1;
+  }else if( iB<0 ){
+    if( iA>0 ){
+      if( iB<SMALLEST_INT64/iA ) return 1;
+    }else if( iA<0 ){
+      if( iB==SMALLEST_INT64 ) return 1;
+      if( iA==SMALLEST_INT64 ) return 1;
+      if( -iA>LARGEST_INT64/-iB ) return 1;
+    }
+  }
+  *pA = iA*iB;
+  return 0;
+#endif
+}
+
+/*
+** Compute the absolute value of a 32-bit signed integer, of possible.  Or
+** if the integer has a value of -2147483648, return +2147483647
+*/
+SQLITE_PRIVATE int sqlite3AbsInt32(int x){
+  if( x>=0 ) return x;
+  if( x==(int)0x80000000 ) return 0x7fffffff;
+  return -x;
+}
+
+#ifdef SQLITE_ENABLE_8_3_NAMES
+/*
+** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
+** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
+** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
+** three characters, then shorten the suffix on z[] to be the last three
+** characters of the original suffix.
+**
+** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
+** do the suffix shortening regardless of URI parameter.
+**
+** Examples:
+**
+**     test.db-journal    =>   test.nal
+**     test.db-wal        =>   test.wal
+**     test.db-shm        =>   test.shm
+**     test.db-mj7f3319fa =>   test.9fa
+*/
+SQLITE_PRIVATE void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
+#if SQLITE_ENABLE_8_3_NAMES<2
+  if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
+#endif
+  {
+    int i, sz;
+    sz = sqlite3Strlen30(z);
+    for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
+    if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
+  }
+}
+#endif
+
+/*
+** Find (an approximate) sum of two LogEst values.  This computation is
+** not a simple "+" operator because LogEst is stored as a logarithmic
+** value.
+**
+*/
+SQLITE_PRIVATE LogEst sqlite3LogEstAdd(LogEst a, LogEst b){
+  static const unsigned char x[] = {
+     10, 10,                         /* 0,1 */
+      9, 9,                          /* 2,3 */
+      8, 8,                          /* 4,5 */
+      7, 7, 7,                       /* 6,7,8 */
+      6, 6, 6,                       /* 9,10,11 */
+      5, 5, 5,                       /* 12-14 */
+      4, 4, 4, 4,                    /* 15-18 */
+      3, 3, 3, 3, 3, 3,              /* 19-24 */
+      2, 2, 2, 2, 2, 2, 2,           /* 25-31 */
+  };
+  if( a>=b ){
+    if( a>b+49 ) return a;
+    if( a>b+31 ) return a+1;
+    return a+x[a-b];
+  }else{
+    if( b>a+49 ) return b;
+    if( b>a+31 ) return b+1;
+    return b+x[b-a];
+  }
+}
+
+/*
+** Convert an integer into a LogEst.  In other words, compute an
+** approximation for 10*log2(x).
+*/
+SQLITE_PRIVATE LogEst sqlite3LogEst(u64 x){
+  static LogEst a[] = { 0, 2, 3, 5, 6, 7, 8, 9 };
+  LogEst y = 40;
+  if( x<8 ){
+    if( x<2 ) return 0;
+    while( x<8 ){  y -= 10; x <<= 1; }
+  }else{
+#if GCC_VERSION>=5004000
+    int i = 60 - __builtin_clzll(x);
+    y += i*10;
+    x >>= i;
+#else
+    while( x>255 ){ y += 40; x >>= 4; }  /*OPTIMIZATION-IF-TRUE*/
+    while( x>15 ){  y += 10; x >>= 1; }
+#endif
+  }
+  return a[x&7] + y - 10;
+}
+
+/*
+** Convert a double into a LogEst
+** In other words, compute an approximation for 10*log2(x).
+*/
+SQLITE_PRIVATE LogEst sqlite3LogEstFromDouble(double x){
+  u64 a;
+  LogEst e;
+  assert( sizeof(x)==8 && sizeof(a)==8 );
+  if( x<=1 ) return 0;
+  if( x<=2000000000 ) return sqlite3LogEst((u64)x);
+  memcpy(&a, &x, 8);
+  e = (a>>52) - 1022;
+  return e*10;
+}
+
+/*
+** Convert a LogEst into an integer.
+*/
+SQLITE_PRIVATE u64 sqlite3LogEstToInt(LogEst x){
+  u64 n;
+  n = x%10;
+  x /= 10;
+  if( n>=5 ) n -= 2;
+  else if( n>=1 ) n -= 1;
+  if( x>60 ) return (u64)LARGEST_INT64;
+  return x>=3 ? (n+8)<<(x-3) : (n+8)>>(3-x);
+}
+
+/*
+** Add a new name/number pair to a VList.  This might require that the
+** VList object be reallocated, so return the new VList.  If an OOM
+** error occurs, the original VList returned and the
+** db->mallocFailed flag is set.
+**
+** A VList is really just an array of integers.  To destroy a VList,
+** simply pass it to sqlite3DbFree().
+**
+** The first integer is the number of integers allocated for the whole
+** VList.  The second integer is the number of integers actually used.
+** Each name/number pair is encoded by subsequent groups of 3 or more
+** integers.
+**
+** Each name/number pair starts with two integers which are the numeric
+** value for the pair and the size of the name/number pair, respectively.
+** The text name overlays one or more following integers.  The text name
+** is always zero-terminated.
+**
+** Conceptually:
+**
+**    struct VList {
+**      int nAlloc;   // Number of allocated slots
+**      int nUsed;    // Number of used slots
+**      struct VListEntry {
+**        int iValue;    // Value for this entry
+**        int nSlot;     // Slots used by this entry
+**        // ... variable name goes here
+**      } a[0];
+**    }
+**
+** During code generation, pointers to the variable names within the
+** VList are taken.  When that happens, nAlloc is set to zero as an
+** indication that the VList may never again be enlarged, since the
+** accompanying realloc() would invalidate the pointers.
+*/
+SQLITE_PRIVATE VList *sqlite3VListAdd(
+  sqlite3 *db,           /* The database connection used for malloc() */
+  VList *pIn,            /* The input VList.  Might be NULL */
+  const char *zName,     /* Name of symbol to add */
+  int nName,             /* Bytes of text in zName */
+  int iVal               /* Value to associate with zName */
+){
+  int nInt;              /* number of sizeof(int) objects needed for zName */
+  char *z;               /* Pointer to where zName will be stored */
+  int i;                 /* Index in pIn[] where zName is stored */
+
+  nInt = nName/4 + 3;
+  assert( pIn==0 || pIn[0]>=3 );  /* Verify ok to add new elements */
+  if( pIn==0 || pIn[1]+nInt > pIn[0] ){
+    /* Enlarge the allocation */
+    sqlite3_int64 nAlloc = (pIn ? 2*(sqlite3_int64)pIn[0] : 10) + nInt;
+    VList *pOut = sqlite3DbRealloc(db, pIn, nAlloc*sizeof(int));
+    if( pOut==0 ) return pIn;
+    if( pIn==0 ) pOut[1] = 2;
+    pIn = pOut;
+    pIn[0] = nAlloc;
+  }
+  i = pIn[1];
+  pIn[i] = iVal;
+  pIn[i+1] = nInt;
+  z = (char*)&pIn[i+2];
+  pIn[1] = i+nInt;
+  assert( pIn[1]<=pIn[0] );
+  memcpy(z, zName, nName);
+  z[nName] = 0;
+  return pIn;
+}
+
+/*
+** Return a pointer to the name of a variable in the given VList that
+** has the value iVal.  Or return a NULL if there is no such variable in
+** the list
+*/
+SQLITE_PRIVATE const char *sqlite3VListNumToName(VList *pIn, int iVal){
+  int i, mx;
+  if( pIn==0 ) return 0;
+  mx = pIn[1];
+  i = 2;
+  do{
+    if( pIn[i]==iVal ) return (char*)&pIn[i+2];
+    i += pIn[i+1];
+  }while( i<mx );
+  return 0;
+}
+
+/*
+** Return the number of the variable named zName, if it is in VList.
+** or return 0 if there is no such variable.
+*/
+SQLITE_PRIVATE int sqlite3VListNameToNum(VList *pIn, const char *zName, int nName){
+  int i, mx;
+  if( pIn==0 ) return 0;
+  mx = pIn[1];
+  i = 2;
+  do{
+    const char *z = (const char*)&pIn[i+2];
+    if( strncmp(z,zName,nName)==0 && z[nName]==0 ) return pIn[i];
+    i += pIn[i+1];
+  }while( i<mx );
+  return 0;
+}
+
+/************** End of util.c ************************************************/
+/************** Begin file hash.c ********************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the implementation of generic hash-tables
+** used in SQLite.
+*/
+/* #include "sqliteInt.h" */
+/* #include <assert.h> */
+
+/* Turn bulk memory into a hash table object by initializing the
+** fields of the Hash structure.
+**
+** "pNew" is a pointer to the hash table that is to be initialized.
+*/
+SQLITE_PRIVATE void sqlite3HashInit(Hash *pNew){
+  assert( pNew!=0 );
+  pNew->first = 0;
+  pNew->count = 0;
+  pNew->htsize = 0;
+  pNew->ht = 0;
+}
+
+/* Remove all entries from a hash table.  Reclaim all memory.
+** Call this routine to delete a hash table or to reset a hash table
+** to the empty state.
+*/
+SQLITE_PRIVATE void sqlite3HashClear(Hash *pH){
+  HashElem *elem;         /* For looping over all elements of the table */
+
+  assert( pH!=0 );
+  elem = pH->first;
+  pH->first = 0;
+  sqlite3_free(pH->ht);
+  pH->ht = 0;
+  pH->htsize = 0;
+  while( elem ){
+    HashElem *next_elem = elem->next;
+    sqlite3_free(elem);
+    elem = next_elem;
+  }
+  pH->count = 0;
+}
+
+/*
+** The hashing function.
+*/
+static unsigned int strHash(const char *z){
+  unsigned int h = 0;
+  unsigned char c;
+  while( (c = (unsigned char)*z++)!=0 ){     /*OPTIMIZATION-IF-TRUE*/
+    /* Knuth multiplicative hashing.  (Sorting & Searching, p. 510).
+    ** 0x9e3779b1 is 2654435761 which is the closest prime number to
+    ** (2**32)*golden_ratio, where golden_ratio = (sqrt(5) - 1)/2. */
+    h += sqlite3UpperToLower[c];
+    h *= 0x9e3779b1;
+  }
+  return h;
+}
+
+
+/* Link pNew element into the hash table pH.  If pEntry!=0 then also
+** insert pNew into the pEntry hash bucket.
+*/
+static void insertElement(
+  Hash *pH,              /* The complete hash table */
+  struct _ht *pEntry,    /* The entry into which pNew is inserted */
+  HashElem *pNew         /* The element to be inserted */
+){
+  HashElem *pHead;       /* First element already in pEntry */
+  if( pEntry ){
+    pHead = pEntry->count ? pEntry->chain : 0;
+    pEntry->count++;
+    pEntry->chain = pNew;
+  }else{
+    pHead = 0;
+  }
+  if( pHead ){
+    pNew->next = pHead;
+    pNew->prev = pHead->prev;
+    if( pHead->prev ){ pHead->prev->next = pNew; }
+    else             { pH->first = pNew; }
+    pHead->prev = pNew;
+  }else{
+    pNew->next = pH->first;
+    if( pH->first ){ pH->first->prev = pNew; }
+    pNew->prev = 0;
+    pH->first = pNew;
+  }
+}
+
+
+/* Resize the hash table so that it contains "new_size" buckets.
+**
+** The hash table might fail to resize if sqlite3_malloc() fails or
+** if the new size is the same as the prior size.
+** Return TRUE if the resize occurs and false if not.
+*/
+static int rehash(Hash *pH, unsigned int new_size){
+  struct _ht *new_ht;            /* The new hash table */
+  HashElem *elem, *next_elem;    /* For looping over existing elements */
+
+#if SQLITE_MALLOC_SOFT_LIMIT>0
+  if( new_size*sizeof(struct _ht)>SQLITE_MALLOC_SOFT_LIMIT ){
+    new_size = SQLITE_MALLOC_SOFT_LIMIT/sizeof(struct _ht);
+  }
+  if( new_size==pH->htsize ) return 0;
+#endif
+
+  /* The inability to allocates space for a larger hash table is
+  ** a performance hit but it is not a fatal error.  So mark the
+  ** allocation as a benign. Use sqlite3Malloc()/memset(0) instead of
+  ** sqlite3MallocZero() to make the allocation, as sqlite3MallocZero()
+  ** only zeroes the requested number of bytes whereas this module will
+  ** use the actual amount of space allocated for the hash table (which
+  ** may be larger than the requested amount).
+  */
+  sqlite3BeginBenignMalloc();
+  new_ht = (struct _ht *)sqlite3Malloc( new_size*sizeof(struct _ht) );
+  sqlite3EndBenignMalloc();
+
+  if( new_ht==0 ) return 0;
+  sqlite3_free(pH->ht);
+  pH->ht = new_ht;
+  pH->htsize = new_size = sqlite3MallocSize(new_ht)/sizeof(struct _ht);
+  memset(new_ht, 0, new_size*sizeof(struct _ht));
+  for(elem=pH->first, pH->first=0; elem; elem = next_elem){
+    unsigned int h = strHash(elem->pKey) % new_size;
+    next_elem = elem->next;
+    insertElement(pH, &new_ht[h], elem);
+  }
+  return 1;
+}
+
+/* This function (for internal use only) locates an element in an
+** hash table that matches the given key.  If no element is found,
+** a pointer to a static null element with HashElem.data==0 is returned.
+** If pH is not NULL, then the hash for this key is written to *pH.
+*/
+static HashElem *findElementWithHash(
+  const Hash *pH,     /* The pH to be searched */
+  const char *pKey,   /* The key we are searching for */
+  unsigned int *pHash /* Write the hash value here */
+){
+  HashElem *elem;                /* Used to loop thru the element list */
+  unsigned int count;            /* Number of elements left to test */
+  unsigned int h;                /* The computed hash */
+  static HashElem nullElement = { 0, 0, 0, 0 };
+
+  if( pH->ht ){   /*OPTIMIZATION-IF-TRUE*/
+    struct _ht *pEntry;
+    h = strHash(pKey) % pH->htsize;
+    pEntry = &pH->ht[h];
+    elem = pEntry->chain;
+    count = pEntry->count;
+  }else{
+    h = 0;
+    elem = pH->first;
+    count = pH->count;
+  }
+  if( pHash ) *pHash = h;
+  while( count ){
+    assert( elem!=0 );
+    if( sqlite3StrICmp(elem->pKey,pKey)==0 ){
+      return elem;
+    }
+    elem = elem->next;
+    count--;
+  }
+  return &nullElement;
+}
+
+/* Remove a single entry from the hash table given a pointer to that
+** element and a hash on the element's key.
+*/
+static void removeElementGivenHash(
+  Hash *pH,         /* The pH containing "elem" */
+  HashElem* elem,   /* The element to be removed from the pH */
+  unsigned int h    /* Hash value for the element */
+){
+  struct _ht *pEntry;
+  if( elem->prev ){
+    elem->prev->next = elem->next;
+  }else{
+    pH->first = elem->next;
+  }
+  if( elem->next ){
+    elem->next->prev = elem->prev;
+  }
+  if( pH->ht ){
+    pEntry = &pH->ht[h];
+    if( pEntry->chain==elem ){
+      pEntry->chain = elem->next;
+    }
+    assert( pEntry->count>0 );
+    pEntry->count--;
+  }
+  sqlite3_free( elem );
+  pH->count--;
+  if( pH->count==0 ){
+    assert( pH->first==0 );
+    assert( pH->count==0 );
+    sqlite3HashClear(pH);
+  }
+}
+
+/* Attempt to locate an element of the hash table pH with a key
+** that matches pKey.  Return the data for this element if it is
+** found, or NULL if there is no match.
+*/
+SQLITE_PRIVATE void *sqlite3HashFind(const Hash *pH, const char *pKey){
+  assert( pH!=0 );
+  assert( pKey!=0 );
+  return findElementWithHash(pH, pKey, 0)->data;
+}
+
+/* Insert an element into the hash table pH.  The key is pKey
+** and the data is "data".
+**
+** If no element exists with a matching key, then a new
+** element is created and NULL is returned.
+**
+** If another element already exists with the same key, then the
+** new data replaces the old data and the old data is returned.
+** The key is not copied in this instance.  If a malloc fails, then
+** the new data is returned and the hash table is unchanged.
+**
+** If the "data" parameter to this function is NULL, then the
+** element corresponding to "key" is removed from the hash table.
+*/
+SQLITE_PRIVATE void *sqlite3HashInsert(Hash *pH, const char *pKey, void *data){
+  unsigned int h;       /* the hash of the key modulo hash table size */
+  HashElem *elem;       /* Used to loop thru the element list */
+  HashElem *new_elem;   /* New element added to the pH */
+
+  assert( pH!=0 );
+  assert( pKey!=0 );
+  elem = findElementWithHash(pH,pKey,&h);
+  if( elem->data ){
+    void *old_data = elem->data;
+    if( data==0 ){
+      removeElementGivenHash(pH,elem,h);
+    }else{
+      elem->data = data;
+      elem->pKey = pKey;
+    }
+    return old_data;
+  }
+  if( data==0 ) return 0;
+  new_elem = (HashElem*)sqlite3Malloc( sizeof(HashElem) );
+  if( new_elem==0 ) return data;
+  new_elem->pKey = pKey;
+  new_elem->data = data;
+  pH->count++;
+  if( pH->count>=10 && pH->count > 2*pH->htsize ){
+    if( rehash(pH, pH->count*2) ){
+      assert( pH->htsize>0 );
+      h = strHash(pKey) % pH->htsize;
+    }
+  }
+  insertElement(pH, pH->ht ? &pH->ht[h] : 0, new_elem);
+  return 0;
+}
+
+/************** End of hash.c ************************************************/
+/************** Begin file opcodes.c *****************************************/
+/* Automatically generated.  Do not edit */
+/* See the tool/mkopcodec.tcl script for details. */
+#if !defined(SQLITE_OMIT_EXPLAIN) \
+ || defined(VDBE_PROFILE) \
+ || defined(SQLITE_DEBUG)
+#if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS) || defined(SQLITE_DEBUG)
+# define OpHelp(X) "\0" X
+#else
+# define OpHelp(X)
+#endif
+SQLITE_PRIVATE const char *sqlite3OpcodeName(int i){
+ static const char *const azName[] = {
+    /*   0 */ "Savepoint"        OpHelp(""),
+    /*   1 */ "AutoCommit"       OpHelp(""),
+    /*   2 */ "Transaction"      OpHelp(""),
+    /*   3 */ "Checkpoint"       OpHelp(""),
+    /*   4 */ "JournalMode"      OpHelp(""),
+    /*   5 */ "Vacuum"           OpHelp(""),
+    /*   6 */ "VFilter"          OpHelp("iplan=r[P3] zplan='P4'"),
+    /*   7 */ "VUpdate"          OpHelp("data=r[P3@P2]"),
+    /*   8 */ "Init"             OpHelp("Start at P2"),
+    /*   9 */ "Goto"             OpHelp(""),
+    /*  10 */ "Gosub"            OpHelp(""),
+    /*  11 */ "InitCoroutine"    OpHelp(""),
+    /*  12 */ "Yield"            OpHelp(""),
+    /*  13 */ "MustBeInt"        OpHelp(""),
+    /*  14 */ "Jump"             OpHelp(""),
+    /*  15 */ "Once"             OpHelp(""),
+    /*  16 */ "If"               OpHelp(""),
+    /*  17 */ "IfNot"            OpHelp(""),
+    /*  18 */ "IsType"           OpHelp("if typeof(P1.P3) in P5 goto P2"),
+    /*  19 */ "Not"              OpHelp("r[P2]= !r[P1]"),
+    /*  20 */ "IfNullRow"        OpHelp("if P1.nullRow then r[P3]=NULL, goto P2"),
+    /*  21 */ "SeekLT"           OpHelp("key=r[P3@P4]"),
+    /*  22 */ "SeekLE"           OpHelp("key=r[P3@P4]"),
+    /*  23 */ "SeekGE"           OpHelp("key=r[P3@P4]"),
+    /*  24 */ "SeekGT"           OpHelp("key=r[P3@P4]"),
+    /*  25 */ "IfNotOpen"        OpHelp("if( !csr[P1] ) goto P2"),
+    /*  26 */ "IfNoHope"         OpHelp("key=r[P3@P4]"),
+    /*  27 */ "NoConflict"       OpHelp("key=r[P3@P4]"),
+    /*  28 */ "NotFound"         OpHelp("key=r[P3@P4]"),
+    /*  29 */ "Found"            OpHelp("key=r[P3@P4]"),
+    /*  30 */ "SeekRowid"        OpHelp("intkey=r[P3]"),
+    /*  31 */ "NotExists"        OpHelp("intkey=r[P3]"),
+    /*  32 */ "Last"             OpHelp(""),
+    /*  33 */ "IfSizeBetween"    OpHelp(""),
+    /*  34 */ "SorterSort"       OpHelp(""),
+    /*  35 */ "Sort"             OpHelp(""),
+    /*  36 */ "Rewind"           OpHelp(""),
+    /*  37 */ "SorterNext"       OpHelp(""),
+    /*  38 */ "Prev"             OpHelp(""),
+    /*  39 */ "Next"             OpHelp(""),
+    /*  40 */ "IdxLE"            OpHelp("key=r[P3@P4]"),
+    /*  41 */ "IdxGT"            OpHelp("key=r[P3@P4]"),
+    /*  42 */ "IdxLT"            OpHelp("key=r[P3@P4]"),
+    /*  43 */ "Or"               OpHelp("r[P3]=(r[P1] || r[P2])"),
+    /*  44 */ "And"              OpHelp("r[P3]=(r[P1] && r[P2])"),
+    /*  45 */ "IdxGE"            OpHelp("key=r[P3@P4]"),
+    /*  46 */ "RowSetRead"       OpHelp("r[P3]=rowset(P1)"),
+    /*  47 */ "RowSetTest"       OpHelp("if r[P3] in rowset(P1) goto P2"),
+    /*  48 */ "Program"          OpHelp(""),
+    /*  49 */ "FkIfZero"         OpHelp("if fkctr[P1]==0 goto P2"),
+    /*  50 */ "IfPos"            OpHelp("if r[P1]>0 then r[P1]-=P3, goto P2"),
+    /*  51 */ "IsNull"           OpHelp("if r[P1]==NULL goto P2"),
+    /*  52 */ "NotNull"          OpHelp("if r[P1]!=NULL goto P2"),
+    /*  53 */ "Ne"               OpHelp("IF r[P3]!=r[P1]"),
+    /*  54 */ "Eq"               OpHelp("IF r[P3]==r[P1]"),
+    /*  55 */ "Gt"               OpHelp("IF r[P3]>r[P1]"),
+    /*  56 */ "Le"               OpHelp("IF r[P3]<=r[P1]"),
+    /*  57 */ "Lt"               OpHelp("IF r[P3]<r[P1]"),
+    /*  58 */ "Ge"               OpHelp("IF r[P3]>=r[P1]"),
+    /*  59 */ "ElseEq"           OpHelp(""),
+    /*  60 */ "IfNotZero"        OpHelp("if r[P1]!=0 then r[P1]--, goto P2"),
+    /*  61 */ "DecrJumpZero"     OpHelp("if (--r[P1])==0 goto P2"),
+    /*  62 */ "IncrVacuum"       OpHelp(""),
+    /*  63 */ "VNext"            OpHelp(""),
+    /*  64 */ "Filter"           OpHelp("if key(P3@P4) not in filter(P1) goto P2"),
+    /*  65 */ "PureFunc"         OpHelp("r[P3]=func(r[P2@NP])"),
+    /*  66 */ "Function"         OpHelp("r[P3]=func(r[P2@NP])"),
+    /*  67 */ "Return"           OpHelp(""),
+    /*  68 */ "EndCoroutine"     OpHelp(""),
+    /*  69 */ "HaltIfNull"       OpHelp("if r[P3]=null halt"),
+    /*  70 */ "Halt"             OpHelp(""),
+    /*  71 */ "Integer"          OpHelp("r[P2]=P1"),
+    /*  72 */ "Int64"            OpHelp("r[P2]=P4"),
+    /*  73 */ "String"           OpHelp("r[P2]='P4' (len=P1)"),
+    /*  74 */ "BeginSubrtn"      OpHelp("r[P2]=NULL"),
+    /*  75 */ "Null"             OpHelp("r[P2..P3]=NULL"),
+    /*  76 */ "SoftNull"         OpHelp("r[P1]=NULL"),
+    /*  77 */ "Blob"             OpHelp("r[P2]=P4 (len=P1)"),
+    /*  78 */ "Variable"         OpHelp("r[P2]=parameter(P1)"),
+    /*  79 */ "Move"             OpHelp("r[P2@P3]=r[P1@P3]"),
+    /*  80 */ "Copy"             OpHelp("r[P2@P3+1]=r[P1@P3+1]"),
+    /*  81 */ "SCopy"            OpHelp("r[P2]=r[P1]"),
+    /*  82 */ "IntCopy"          OpHelp("r[P2]=r[P1]"),
+    /*  83 */ "FkCheck"          OpHelp(""),
+    /*  84 */ "ResultRow"        OpHelp("output=r[P1@P2]"),
+    /*  85 */ "CollSeq"          OpHelp(""),
+    /*  86 */ "AddImm"           OpHelp("r[P1]=r[P1]+P2"),
+    /*  87 */ "RealAffinity"     OpHelp(""),
+    /*  88 */ "Cast"             OpHelp("affinity(r[P1])"),
+    /*  89 */ "Permutation"      OpHelp(""),
+    /*  90 */ "Compare"          OpHelp("r[P1@P3] <-> r[P2@P3]"),
+    /*  91 */ "IsTrue"           OpHelp("r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4"),
+    /*  92 */ "ZeroOrNull"       OpHelp("r[P2] = 0 OR NULL"),
+    /*  93 */ "Offset"           OpHelp("r[P3] = sqlite_offset(P1)"),
+    /*  94 */ "Column"           OpHelp("r[P3]=PX cursor P1 column P2"),
+    /*  95 */ "TypeCheck"        OpHelp("typecheck(r[P1@P2])"),
+    /*  96 */ "Affinity"         OpHelp("affinity(r[P1@P2])"),
+    /*  97 */ "MakeRecord"       OpHelp("r[P3]=mkrec(r[P1@P2])"),
+    /*  98 */ "Count"            OpHelp("r[P2]=count()"),
+    /*  99 */ "ReadCookie"       OpHelp(""),
+    /* 100 */ "SetCookie"        OpHelp(""),
+    /* 101 */ "ReopenIdx"        OpHelp("root=P2 iDb=P3"),
+    /* 102 */ "OpenRead"         OpHelp("root=P2 iDb=P3"),
+    /* 103 */ "BitAnd"           OpHelp("r[P3]=r[P1]&r[P2]"),
+    /* 104 */ "BitOr"            OpHelp("r[P3]=r[P1]|r[P2]"),
+    /* 105 */ "ShiftLeft"        OpHelp("r[P3]=r[P2]<<r[P1]"),
+    /* 106 */ "ShiftRight"       OpHelp("r[P3]=r[P2]>>r[P1]"),
+    /* 107 */ "Add"              OpHelp("r[P3]=r[P1]+r[P2]"),
+    /* 108 */ "Subtract"         OpHelp("r[P3]=r[P2]-r[P1]"),
+    /* 109 */ "Multiply"         OpHelp("r[P3]=r[P1]*r[P2]"),
+    /* 110 */ "Divide"           OpHelp("r[P3]=r[P2]/r[P1]"),
+    /* 111 */ "Remainder"        OpHelp("r[P3]=r[P2]%r[P1]"),
+    /* 112 */ "Concat"           OpHelp("r[P3]=r[P2]+r[P1]"),
+    /* 113 */ "OpenWrite"        OpHelp("root=P2 iDb=P3"),
+    /* 114 */ "OpenDup"          OpHelp(""),
+    /* 115 */ "BitNot"           OpHelp("r[P2]= ~r[P1]"),
+    /* 116 */ "OpenAutoindex"    OpHelp("nColumn=P2"),
+    /* 117 */ "OpenEphemeral"    OpHelp("nColumn=P2"),
+    /* 118 */ "String8"          OpHelp("r[P2]='P4'"),
+    /* 119 */ "SorterOpen"       OpHelp(""),
+    /* 120 */ "SequenceTest"     OpHelp("if( cursor[P1].ctr++ ) pc = P2"),
+    /* 121 */ "OpenPseudo"       OpHelp("P3 columns in r[P2]"),
+    /* 122 */ "Close"            OpHelp(""),
+    /* 123 */ "ColumnsUsed"      OpHelp(""),
+    /* 124 */ "SeekScan"         OpHelp("Scan-ahead up to P1 rows"),
+    /* 125 */ "SeekHit"          OpHelp("set P2<=seekHit<=P3"),
+    /* 126 */ "Sequence"         OpHelp("r[P2]=cursor[P1].ctr++"),
+    /* 127 */ "NewRowid"         OpHelp("r[P2]=rowid"),
+    /* 128 */ "Insert"           OpHelp("intkey=r[P3] data=r[P2]"),
+    /* 129 */ "RowCell"          OpHelp(""),
+    /* 130 */ "Delete"           OpHelp(""),
+    /* 131 */ "ResetCount"       OpHelp(""),
+    /* 132 */ "SorterCompare"    OpHelp("if key(P1)!=trim(r[P3],P4) goto P2"),
+    /* 133 */ "SorterData"       OpHelp("r[P2]=data"),
+    /* 134 */ "RowData"          OpHelp("r[P2]=data"),
+    /* 135 */ "Rowid"            OpHelp("r[P2]=PX rowid of P1"),
+    /* 136 */ "NullRow"          OpHelp(""),
+    /* 137 */ "SeekEnd"          OpHelp(""),
+    /* 138 */ "IdxInsert"        OpHelp("key=r[P2]"),
+    /* 139 */ "SorterInsert"     OpHelp("key=r[P2]"),
+    /* 140 */ "IdxDelete"        OpHelp("key=r[P2@P3]"),
+    /* 141 */ "DeferredSeek"     OpHelp("Move P3 to P1.rowid if needed"),
+    /* 142 */ "IdxRowid"         OpHelp("r[P2]=rowid"),
+    /* 143 */ "FinishSeek"       OpHelp(""),
+    /* 144 */ "Destroy"          OpHelp(""),
+    /* 145 */ "Clear"            OpHelp(""),
+    /* 146 */ "ResetSorter"      OpHelp(""),
+    /* 147 */ "CreateBtree"      OpHelp("r[P2]=root iDb=P1 flags=P3"),
+    /* 148 */ "SqlExec"          OpHelp(""),
+    /* 149 */ "ParseSchema"      OpHelp(""),
+    /* 150 */ "LoadAnalysis"     OpHelp(""),
+    /* 151 */ "DropTable"        OpHelp(""),
+    /* 152 */ "DropIndex"        OpHelp(""),
+    /* 153 */ "DropTrigger"      OpHelp(""),
+    /* 154 */ "Real"             OpHelp("r[P2]=P4"),
+    /* 155 */ "IntegrityCk"      OpHelp(""),
+    /* 156 */ "RowSetAdd"        OpHelp("rowset(P1)=r[P2]"),
+    /* 157 */ "Param"            OpHelp(""),
+    /* 158 */ "FkCounter"        OpHelp("fkctr[P1]+=P2"),
+    /* 159 */ "MemMax"           OpHelp("r[P1]=max(r[P1],r[P2])"),
+    /* 160 */ "OffsetLimit"      OpHelp("if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1)"),
+    /* 161 */ "AggInverse"       OpHelp("accum=r[P3] inverse(r[P2@P5])"),
+    /* 162 */ "AggStep"          OpHelp("accum=r[P3] step(r[P2@P5])"),
+    /* 163 */ "AggStep1"         OpHelp("accum=r[P3] step(r[P2@P5])"),
+    /* 164 */ "AggValue"         OpHelp("r[P3]=value N=P2"),
+    /* 165 */ "AggFinal"         OpHelp("accum=r[P1] N=P2"),
+    /* 166 */ "Expire"           OpHelp(""),
+    /* 167 */ "CursorLock"       OpHelp(""),
+    /* 168 */ "CursorUnlock"     OpHelp(""),
+    /* 169 */ "TableLock"        OpHelp("iDb=P1 root=P2 write=P3"),
+    /* 170 */ "VBegin"           OpHelp(""),
+    /* 171 */ "VCreate"          OpHelp(""),
+    /* 172 */ "VDestroy"         OpHelp(""),
+    /* 173 */ "VOpen"            OpHelp(""),
+    /* 174 */ "VCheck"           OpHelp(""),
+    /* 175 */ "VInitIn"          OpHelp("r[P2]=ValueList(P1,P3)"),
+    /* 176 */ "VColumn"          OpHelp("r[P3]=vcolumn(P2)"),
+    /* 177 */ "VRename"          OpHelp(""),
+    /* 178 */ "Pagecount"        OpHelp(""),
+    /* 179 */ "MaxPgcnt"         OpHelp(""),
+    /* 180 */ "ClrSubtype"       OpHelp("r[P1].subtype = 0"),
+    /* 181 */ "GetSubtype"       OpHelp("r[P2] = r[P1].subtype"),
+    /* 182 */ "SetSubtype"       OpHelp("r[P2].subtype = r[P1]"),
+    /* 183 */ "FilterAdd"        OpHelp("filter(P1) += key(P3@P4)"),
+    /* 184 */ "Trace"            OpHelp(""),
+    /* 185 */ "CursorHint"       OpHelp(""),
+    /* 186 */ "ReleaseReg"       OpHelp("release r[P1@P2] mask P3"),
+    /* 187 */ "Noop"             OpHelp(""),
+    /* 188 */ "Explain"          OpHelp(""),
+    /* 189 */ "Abortable"        OpHelp(""),
+  };
+  return azName[i];
+}
+#endif
+
+/************** End of opcodes.c *********************************************/
+/************** Begin file os_kv.c *******************************************/
+/*
+** 2022-09-06
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains an experimental VFS layer that operates on a
+** Key/Value storage engine where both keys and values must be pure
+** text.
+*/
+/* #include <sqliteInt.h> */
+#if SQLITE_OS_KV || (SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL))
+
+/*****************************************************************************
+** Debugging logic
+*/
+
+/* SQLITE_KV_TRACE() is used for tracing calls to kvstorage routines. */
+#if 0
+#define SQLITE_KV_TRACE(X)  printf X
+#else
+#define SQLITE_KV_TRACE(X)
+#endif
+
+/* SQLITE_KV_LOG() is used for tracing calls to the VFS interface */
+#if 0
+#define SQLITE_KV_LOG(X)  printf X
+#else
+#define SQLITE_KV_LOG(X)
+#endif
+
+
+/*
+** Forward declaration of objects used by this VFS implementation
+*/
+typedef struct KVVfsFile KVVfsFile;
+
+/* A single open file.  There are only two files represented by this
+** VFS - the database and the rollback journal.
+*/
+struct KVVfsFile {
+  sqlite3_file base;              /* IO methods */
+  const char *zClass;             /* Storage class */
+  int isJournal;                  /* True if this is a journal file */
+  unsigned int nJrnl;             /* Space allocated for aJrnl[] */
+  char *aJrnl;                    /* Journal content */
+  int szPage;                     /* Last known page size */
+  sqlite3_int64 szDb;             /* Database file size.  -1 means unknown */
+  char *aData;                    /* Buffer to hold page data */
+};
+#define SQLITE_KVOS_SZ 133073
+
+/*
+** Methods for KVVfsFile
+*/
+static int kvvfsClose(sqlite3_file*);
+static int kvvfsReadDb(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int kvvfsReadJrnl(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int kvvfsWriteDb(sqlite3_file*,const void*,int iAmt, sqlite3_int64);
+static int kvvfsWriteJrnl(sqlite3_file*,const void*,int iAmt, sqlite3_int64);
+static int kvvfsTruncateDb(sqlite3_file*, sqlite3_int64 size);
+static int kvvfsTruncateJrnl(sqlite3_file*, sqlite3_int64 size);
+static int kvvfsSyncDb(sqlite3_file*, int flags);
+static int kvvfsSyncJrnl(sqlite3_file*, int flags);
+static int kvvfsFileSizeDb(sqlite3_file*, sqlite3_int64 *pSize);
+static int kvvfsFileSizeJrnl(sqlite3_file*, sqlite3_int64 *pSize);
+static int kvvfsLock(sqlite3_file*, int);
+static int kvvfsUnlock(sqlite3_file*, int);
+static int kvvfsCheckReservedLock(sqlite3_file*, int *pResOut);
+static int kvvfsFileControlDb(sqlite3_file*, int op, void *pArg);
+static int kvvfsFileControlJrnl(sqlite3_file*, int op, void *pArg);
+static int kvvfsSectorSize(sqlite3_file*);
+static int kvvfsDeviceCharacteristics(sqlite3_file*);
+
+/*
+** Methods for sqlite3_vfs
+*/
+static int kvvfsOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
+static int kvvfsDelete(sqlite3_vfs*, const char *zName, int syncDir);
+static int kvvfsAccess(sqlite3_vfs*, const char *zName, int flags, int *);
+static int kvvfsFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
+static void *kvvfsDlOpen(sqlite3_vfs*, const char *zFilename);
+static int kvvfsRandomness(sqlite3_vfs*, int nByte, char *zOut);
+static int kvvfsSleep(sqlite3_vfs*, int microseconds);
+static int kvvfsCurrentTime(sqlite3_vfs*, double*);
+static int kvvfsCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
+
+static sqlite3_vfs sqlite3OsKvvfsObject = {
+  1,                              /* iVersion */
+  sizeof(KVVfsFile),              /* szOsFile */
+  1024,                           /* mxPathname */
+  0,                              /* pNext */
+  "kvvfs",                        /* zName */
+  0,                              /* pAppData */
+  kvvfsOpen,                      /* xOpen */
+  kvvfsDelete,                    /* xDelete */
+  kvvfsAccess,                    /* xAccess */
+  kvvfsFullPathname,              /* xFullPathname */
+  kvvfsDlOpen,                    /* xDlOpen */
+  0,                              /* xDlError */
+  0,                              /* xDlSym */
+  0,                              /* xDlClose */
+  kvvfsRandomness,                /* xRandomness */
+  kvvfsSleep,                     /* xSleep */
+  kvvfsCurrentTime,               /* xCurrentTime */
+  0,                              /* xGetLastError */
+  kvvfsCurrentTimeInt64           /* xCurrentTimeInt64 */
+};
+
+/* Methods for sqlite3_file objects referencing a database file
+*/
+static sqlite3_io_methods kvvfs_db_io_methods = {
+  1,                              /* iVersion */
+  kvvfsClose,                     /* xClose */
+  kvvfsReadDb,                    /* xRead */
+  kvvfsWriteDb,                   /* xWrite */
+  kvvfsTruncateDb,                /* xTruncate */
+  kvvfsSyncDb,                    /* xSync */
+  kvvfsFileSizeDb,                /* xFileSize */
+  kvvfsLock,                      /* xLock */
+  kvvfsUnlock,                    /* xUnlock */
+  kvvfsCheckReservedLock,         /* xCheckReservedLock */
+  kvvfsFileControlDb,             /* xFileControl */
+  kvvfsSectorSize,                /* xSectorSize */
+  kvvfsDeviceCharacteristics,     /* xDeviceCharacteristics */
+  0,                              /* xShmMap */
+  0,                              /* xShmLock */
+  0,                              /* xShmBarrier */
+  0,                              /* xShmUnmap */
+  0,                              /* xFetch */
+  0                               /* xUnfetch */
+};
+
+/* Methods for sqlite3_file objects referencing a rollback journal
+*/
+static sqlite3_io_methods kvvfs_jrnl_io_methods = {
+  1,                              /* iVersion */
+  kvvfsClose,                     /* xClose */
+  kvvfsReadJrnl,                  /* xRead */
+  kvvfsWriteJrnl,                 /* xWrite */
+  kvvfsTruncateJrnl,              /* xTruncate */
+  kvvfsSyncJrnl,                  /* xSync */
+  kvvfsFileSizeJrnl,              /* xFileSize */
+  kvvfsLock,                      /* xLock */
+  kvvfsUnlock,                    /* xUnlock */
+  kvvfsCheckReservedLock,         /* xCheckReservedLock */
+  kvvfsFileControlJrnl,           /* xFileControl */
+  kvvfsSectorSize,                /* xSectorSize */
+  kvvfsDeviceCharacteristics,     /* xDeviceCharacteristics */
+  0,                              /* xShmMap */
+  0,                              /* xShmLock */
+  0,                              /* xShmBarrier */
+  0,                              /* xShmUnmap */
+  0,                              /* xFetch */
+  0                               /* xUnfetch */
+};
+
+/****** Storage subsystem **************************************************/
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+/* Forward declarations for the low-level storage engine
+*/
+static int kvstorageWrite(const char*, const char *zKey, const char *zData);
+static int kvstorageDelete(const char*, const char *zKey);
+static int kvstorageRead(const char*, const char *zKey, char *zBuf, int nBuf);
+#define KVSTORAGE_KEY_SZ  32
+
+/* Expand the key name with an appropriate prefix and put the result
+** zKeyOut[].  The zKeyOut[] buffer is assumed to hold at least
+** KVSTORAGE_KEY_SZ bytes.
+*/
+static void kvstorageMakeKey(
+  const char *zClass,
+  const char *zKeyIn,
+  char *zKeyOut
+){
+  sqlite3_snprintf(KVSTORAGE_KEY_SZ, zKeyOut, "kvvfs-%s-%s", zClass, zKeyIn);
+}
+
+/* Write content into a key.  zClass is the particular namespace of the
+** underlying key/value store to use - either "local" or "session".
+**
+** Both zKey and zData are zero-terminated pure text strings.
+**
+** Return the number of errors.
+*/
+static int kvstorageWrite(
+  const char *zClass,
+  const char *zKey,
+  const char *zData
+){
+  FILE *fd;
+  char zXKey[KVSTORAGE_KEY_SZ];
+  kvstorageMakeKey(zClass, zKey, zXKey);
+  fd = fopen(zXKey, "wb");
+  if( fd ){
+    SQLITE_KV_TRACE(("KVVFS-WRITE  %-15s (%d) %.50s%s\n", zXKey,
+                 (int)strlen(zData), zData,
+                 strlen(zData)>50 ? "..." : ""));
+    fputs(zData, fd);
+    fclose(fd);
+    return 0;
+  }else{
+    return 1;
+  }
+}
+
+/* Delete a key (with its corresponding data) from the key/value
+** namespace given by zClass.  If the key does not previously exist,
+** this routine is a no-op.
+*/
+static int kvstorageDelete(const char *zClass, const char *zKey){
+  char zXKey[KVSTORAGE_KEY_SZ];
+  kvstorageMakeKey(zClass, zKey, zXKey);
+  unlink(zXKey);
+  SQLITE_KV_TRACE(("KVVFS-DELETE %-15s\n", zXKey));
+  return 0;
+}
+
+/* Read the value associated with a zKey from the key/value namespace given
+** by zClass and put the text data associated with that key in the first
+** nBuf bytes of zBuf[].  The value might be truncated if zBuf is not large
+** enough to hold it all.  The value put into zBuf must always be zero
+** terminated, even if it gets truncated because nBuf is not large enough.
+**
+** Return the total number of bytes in the data, without truncation, and
+** not counting the final zero terminator.   Return -1 if the key does
+** not exist.
+**
+** If nBuf<=0 then this routine simply returns the size of the data without
+** actually reading it.
+*/
+static int kvstorageRead(
+  const char *zClass,
+  const char *zKey,
+  char *zBuf,
+  int nBuf
+){
+  FILE *fd;
+  struct stat buf;
+  char zXKey[KVSTORAGE_KEY_SZ];
+  kvstorageMakeKey(zClass, zKey, zXKey);
+  if( access(zXKey, R_OK)!=0
+   || stat(zXKey, &buf)!=0
+   || !S_ISREG(buf.st_mode)
+  ){
+    SQLITE_KV_TRACE(("KVVFS-READ   %-15s (-1)\n", zXKey));
+    return -1;
+  }
+  if( nBuf<=0 ){
+    return (int)buf.st_size;
+  }else if( nBuf==1 ){
+    zBuf[0] = 0;
+    SQLITE_KV_TRACE(("KVVFS-READ   %-15s (%d)\n", zXKey,
+                 (int)buf.st_size));
+    return (int)buf.st_size;
+  }
+  if( nBuf > buf.st_size + 1 ){
+    nBuf = buf.st_size + 1;
+  }
+  fd = fopen(zXKey, "rb");
+  if( fd==0 ){
+    SQLITE_KV_TRACE(("KVVFS-READ   %-15s (-1)\n", zXKey));
+    return -1;
+  }else{
+    sqlite3_int64 n = fread(zBuf, 1, nBuf-1, fd);
+    fclose(fd);
+    zBuf[n] = 0;
+    SQLITE_KV_TRACE(("KVVFS-READ   %-15s (%lld) %.50s%s\n", zXKey,
+                 n, zBuf, n>50 ? "..." : ""));
+    return (int)n;
+  }
+}
+
+/*
+** An internal level of indirection which enables us to replace the
+** kvvfs i/o methods with JavaScript implementations in WASM builds.
+** Maintenance reminder: if this struct changes in any way, the JSON
+** rendering of its structure must be updated in
+** sqlite3_wasm_enum_json(). There are no binary compatibility
+** concerns, so it does not need an iVersion member. This file is
+** necessarily always compiled together with sqlite3_wasm_enum_json(),
+** and JS code dynamically creates the mapping of members based on
+** that JSON description.
+*/
+typedef struct sqlite3_kvvfs_methods sqlite3_kvvfs_methods;
+struct sqlite3_kvvfs_methods {
+  int (*xRead)(const char *zClass, const char *zKey, char *zBuf, int nBuf);
+  int (*xWrite)(const char *zClass, const char *zKey, const char *zData);
+  int (*xDelete)(const char *zClass, const char *zKey);
+  const int nKeySize;
+};
+
+/*
+** This object holds the kvvfs I/O methods which may be swapped out
+** for JavaScript-side implementations in WASM builds. In such builds
+** it cannot be const, but in native builds it should be so that
+** the compiler can hopefully optimize this level of indirection out.
+** That said, kvvfs is intended primarily for use in WASM builds.
+**
+** Note that this is not explicitly flagged as static because the
+** amalgamation build will tag it with SQLITE_PRIVATE.
+*/
+#ifndef SQLITE_WASM
+const
+#endif
+SQLITE_PRIVATE sqlite3_kvvfs_methods sqlite3KvvfsMethods = {
+kvstorageRead,
+kvstorageWrite,
+kvstorageDelete,
+KVSTORAGE_KEY_SZ
+};
+
+/****** Utility subroutines ************************************************/
+
+/*
+** Encode binary into the text encoded used to persist on disk.
+** The output text is stored in aOut[], which must be at least
+** nData+1 bytes in length.
+**
+** Return the actual length of the encoded text, not counting the
+** zero terminator at the end.
+**
+** Encoding format
+** ---------------
+**
+**   *  Non-zero bytes are encoded as upper-case hexadecimal
+**
+**   *  A sequence of one or more zero-bytes that are not at the
+**      beginning of the buffer are encoded as a little-endian
+**      base-26 number using a..z.  "a" means 0.  "b" means 1,
+**      "z" means 25.  "ab" means 26.  "ac" means 52.  And so forth.
+**
+**   *  Because there is no overlap between the encoding characters
+**      of hexadecimal and base-26 numbers, it is always clear where
+**      one stops and the next begins.
+*/
+static int kvvfsEncode(const char *aData, int nData, char *aOut){
+  int i, j;
+  const unsigned char *a = (const unsigned char*)aData;
+  for(i=j=0; i<nData; i++){
+    unsigned char c = a[i];
+    if( c!=0 ){
+      aOut[j++] = "0123456789ABCDEF"[c>>4];
+      aOut[j++] = "0123456789ABCDEF"[c&0xf];
+    }else{
+      /* A sequence of 1 or more zeros is stored as a little-endian
+      ** base-26 number using a..z as the digits. So one zero is "b".
+      ** Two zeros is "c". 25 zeros is "z", 26 zeros is "ab", 27 is "bb",
+      ** and so forth.
+      */
+      int k;
+      for(k=1; i+k<nData && a[i+k]==0; k++){}
+      i += k-1;
+      while( k>0 ){
+        aOut[j++] = 'a'+(k%26);
+        k /= 26;
+      }
+    }
+  }
+  aOut[j] = 0;
+  return j;
+}
+
+static const signed char kvvfsHexValue[256] = {
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+   0,  1,  2,  3,  4,  5,  6,  7,    8,  9, -1, -1, -1, -1, -1, -1,
+  -1, 10, 11, 12, 13, 14, 15, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1
+};
+
+/*
+** Decode the text encoding back to binary.  The binary content is
+** written into pOut, which must be at least nOut bytes in length.
+**
+** The return value is the number of bytes actually written into aOut[].
+*/
+static int kvvfsDecode(const char *a, char *aOut, int nOut){
+  int i, j;
+  int c;
+  const unsigned char *aIn = (const unsigned char*)a;
+  i = 0;
+  j = 0;
+  while( 1 ){
+    c = kvvfsHexValue[aIn[i]];
+    if( c<0 ){
+      int n = 0;
+      int mult = 1;
+      c = aIn[i];
+      if( c==0 ) break;
+      while( c>='a' && c<='z' ){
+        n += (c - 'a')*mult;
+        mult *= 26;
+        c = aIn[++i];
+      }
+      if( j+n>nOut ) return -1;
+      memset(&aOut[j], 0, n);
+      j += n;
+      if( c==0 || mult==1 ) break; /* progress stalled if mult==1 */
+    }else{
+      aOut[j] = c<<4;
+      c = kvvfsHexValue[aIn[++i]];
+      if( c<0 ) break;
+      aOut[j++] += c;
+      i++;
+    }
+  }
+  return j;
+}
+
+/*
+** Decode a complete journal file.  Allocate space in pFile->aJrnl
+** and store the decoding there.  Or leave pFile->aJrnl set to NULL
+** if an error is encountered.
+**
+** The first few characters of the text encoding will be a little-endian
+** base-26 number (digits a..z) that is the total number of bytes
+** in the decoded journal file image.  This base-26 number is followed
+** by a single space, then the encoding of the journal.  The space
+** separator is required to act as a terminator for the base-26 number.
+*/
+static void kvvfsDecodeJournal(
+  KVVfsFile *pFile,      /* Store decoding in pFile->aJrnl */
+  const char *zTxt,      /* Text encoding.  Zero-terminated */
+  int nTxt               /* Bytes in zTxt, excluding zero terminator */
+){
+  unsigned int n = 0;
+  int c, i, mult;
+  i = 0;
+  mult = 1;
+  while( (c = zTxt[i++])>='a' && c<='z' ){
+    n += (zTxt[i] - 'a')*mult;
+    mult *= 26;
+  }
+  sqlite3_free(pFile->aJrnl);
+  pFile->aJrnl = sqlite3_malloc64( n );
+  if( pFile->aJrnl==0 ){
+    pFile->nJrnl = 0;
+    return;
+  }
+  pFile->nJrnl = n;
+  n = kvvfsDecode(zTxt+i, pFile->aJrnl, pFile->nJrnl);
+  if( n<pFile->nJrnl ){
+    sqlite3_free(pFile->aJrnl);
+    pFile->aJrnl = 0;
+    pFile->nJrnl = 0;
+  }
+}
+
+/*
+** Read or write the "sz" element, containing the database file size.
+*/
+static sqlite3_int64 kvvfsReadFileSize(KVVfsFile *pFile){
+  char zData[50];
+  zData[0] = 0;
+  sqlite3KvvfsMethods.xRead(pFile->zClass, "sz", zData, sizeof(zData)-1);
+  return strtoll(zData, 0, 0);
+}
+static int kvvfsWriteFileSize(KVVfsFile *pFile, sqlite3_int64 sz){
+  char zData[50];
+  sqlite3_snprintf(sizeof(zData), zData, "%lld", sz);
+  return sqlite3KvvfsMethods.xWrite(pFile->zClass, "sz", zData);
+}
+
+/****** sqlite3_io_methods methods ******************************************/
+
+/*
+** Close an kvvfs-file.
+*/
+static int kvvfsClose(sqlite3_file *pProtoFile){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+
+  SQLITE_KV_LOG(("xClose %s %s\n", pFile->zClass,
+             pFile->isJournal ? "journal" : "db"));
+  sqlite3_free(pFile->aJrnl);
+  sqlite3_free(pFile->aData);
+  return SQLITE_OK;
+}
+
+/*
+** Read from the -journal file.
+*/
+static int kvvfsReadJrnl(
+  sqlite3_file *pProtoFile,
+  void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  assert( pFile->isJournal );
+  SQLITE_KV_LOG(("xRead('%s-journal',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+  if( pFile->aJrnl==0 ){
+    int szTxt = kvstorageRead(pFile->zClass, "jrnl", 0, 0);
+    char *aTxt;
+    if( szTxt<=4 ){
+      return SQLITE_IOERR;
+    }
+    aTxt = sqlite3_malloc64( szTxt+1 );
+    if( aTxt==0 ) return SQLITE_NOMEM;
+    kvstorageRead(pFile->zClass, "jrnl", aTxt, szTxt+1);
+    kvvfsDecodeJournal(pFile, aTxt, szTxt);
+    sqlite3_free(aTxt);
+    if( pFile->aJrnl==0 ) return SQLITE_IOERR;
+  }
+  if( iOfst+iAmt>pFile->nJrnl ){
+    return SQLITE_IOERR_SHORT_READ;
+  }
+  memcpy(zBuf, pFile->aJrnl+iOfst, iAmt);
+  return SQLITE_OK;
+}
+
+/*
+** Read from the database file.
+*/
+static int kvvfsReadDb(
+  sqlite3_file *pProtoFile,
+  void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  unsigned int pgno;
+  int got, n;
+  char zKey[30];
+  char *aData = pFile->aData;
+  assert( iOfst>=0 );
+  assert( iAmt>=0 );
+  SQLITE_KV_LOG(("xRead('%s-db',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+  if( iOfst+iAmt>=512 ){
+    if( (iOfst % iAmt)!=0 ){
+      return SQLITE_IOERR_READ;
+    }
+    if( (iAmt & (iAmt-1))!=0 || iAmt<512 || iAmt>65536 ){
+      return SQLITE_IOERR_READ;
+    }
+    pFile->szPage = iAmt;
+    pgno = 1 + iOfst/iAmt;
+  }else{
+    pgno = 1;
+  }
+  sqlite3_snprintf(sizeof(zKey), zKey, "%u", pgno);
+  got = sqlite3KvvfsMethods.xRead(pFile->zClass, zKey,
+                                  aData, SQLITE_KVOS_SZ-1);
+  if( got<0 ){
+    n = 0;
+  }else{
+    aData[got] = 0;
+    if( iOfst+iAmt<512 ){
+      int k = iOfst+iAmt;
+      aData[k*2] = 0;
+      n = kvvfsDecode(aData, &aData[2000], SQLITE_KVOS_SZ-2000);
+      if( n>=iOfst+iAmt ){
+        memcpy(zBuf, &aData[2000+iOfst], iAmt);
+        n = iAmt;
+      }else{
+        n = 0;
+      }
+    }else{
+      n = kvvfsDecode(aData, zBuf, iAmt);
+    }
+  }
+  if( n<iAmt ){
+    memset(zBuf+n, 0, iAmt-n);
+    return SQLITE_IOERR_SHORT_READ;
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** Write into the -journal file.
+*/
+static int kvvfsWriteJrnl(
+  sqlite3_file *pProtoFile,
+  const void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  sqlite3_int64 iEnd = iOfst+iAmt;
+  SQLITE_KV_LOG(("xWrite('%s-journal',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+  if( iEnd>=0x10000000 ) return SQLITE_FULL;
+  if( pFile->aJrnl==0 || pFile->nJrnl<iEnd ){
+    char *aNew = sqlite3_realloc(pFile->aJrnl, iEnd);
+    if( aNew==0 ){
+      return SQLITE_IOERR_NOMEM;
+    }
+    pFile->aJrnl = aNew;
+    if( pFile->nJrnl<iOfst ){
+      memset(pFile->aJrnl+pFile->nJrnl, 0, iOfst-pFile->nJrnl);
+    }
+    pFile->nJrnl = iEnd;
+  }
+  memcpy(pFile->aJrnl+iOfst, zBuf, iAmt);
+  return SQLITE_OK;
+}
+
+/*
+** Write into the database file.
+*/
+static int kvvfsWriteDb(
+  sqlite3_file *pProtoFile,
+  const void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  unsigned int pgno;
+  char zKey[30];
+  char *aData = pFile->aData;
+  SQLITE_KV_LOG(("xWrite('%s-db',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+  assert( iAmt>=512 && iAmt<=65536 );
+  assert( (iAmt & (iAmt-1))==0 );
+  assert( pFile->szPage<0 || pFile->szPage==iAmt );
+  pFile->szPage = iAmt;
+  pgno = 1 + iOfst/iAmt;
+  sqlite3_snprintf(sizeof(zKey), zKey, "%u", pgno);
+  kvvfsEncode(zBuf, iAmt, aData);
+  if( sqlite3KvvfsMethods.xWrite(pFile->zClass, zKey, aData) ){
+    return SQLITE_IOERR;
+  }
+  if( iOfst+iAmt > pFile->szDb ){
+    pFile->szDb = iOfst + iAmt;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Truncate an kvvfs-file.
+*/
+static int kvvfsTruncateJrnl(sqlite3_file *pProtoFile, sqlite_int64 size){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  SQLITE_KV_LOG(("xTruncate('%s-journal',%lld)\n", pFile->zClass, size));
+  assert( size==0 );
+  sqlite3KvvfsMethods.xDelete(pFile->zClass, "jrnl");
+  sqlite3_free(pFile->aJrnl);
+  pFile->aJrnl = 0;
+  pFile->nJrnl = 0;
+  return SQLITE_OK;
+}
+static int kvvfsTruncateDb(sqlite3_file *pProtoFile, sqlite_int64 size){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  if( pFile->szDb>size
+   && pFile->szPage>0
+   && (size % pFile->szPage)==0
+  ){
+    char zKey[50];
+    unsigned int pgno, pgnoMax;
+    SQLITE_KV_LOG(("xTruncate('%s-db',%lld)\n", pFile->zClass, size));
+    pgno = 1 + size/pFile->szPage;
+    pgnoMax = 2 + pFile->szDb/pFile->szPage;
+    while( pgno<=pgnoMax ){
+      sqlite3_snprintf(sizeof(zKey), zKey, "%u", pgno);
+      sqlite3KvvfsMethods.xDelete(pFile->zClass, zKey);
+      pgno++;
+    }
+    pFile->szDb = size;
+    return kvvfsWriteFileSize(pFile, size) ? SQLITE_IOERR : SQLITE_OK;
+  }
+  return SQLITE_IOERR;
+}
+
+/*
+** Sync an kvvfs-file.
+*/
+static int kvvfsSyncJrnl(sqlite3_file *pProtoFile, int flags){
+  int i, n;
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  char *zOut;
+  SQLITE_KV_LOG(("xSync('%s-journal')\n", pFile->zClass));
+  if( pFile->nJrnl<=0 ){
+    return kvvfsTruncateJrnl(pProtoFile, 0);
+  }
+  zOut = sqlite3_malloc64( pFile->nJrnl*2 + 50 );
+  if( zOut==0 ){
+    return SQLITE_IOERR_NOMEM;
+  }
+  n = pFile->nJrnl;
+  i = 0;
+  do{
+    zOut[i++] = 'a' + (n%26);
+    n /= 26;
+  }while( n>0 );
+  zOut[i++] = ' ';
+  kvvfsEncode(pFile->aJrnl, pFile->nJrnl, &zOut[i]);
+  i = sqlite3KvvfsMethods.xWrite(pFile->zClass, "jrnl", zOut);
+  sqlite3_free(zOut);
+  return i ? SQLITE_IOERR : SQLITE_OK;
+}
+static int kvvfsSyncDb(sqlite3_file *pProtoFile, int flags){
+  return SQLITE_OK;
+}
+
+/*
+** Return the current file-size of an kvvfs-file.
+*/
+static int kvvfsFileSizeJrnl(sqlite3_file *pProtoFile, sqlite_int64 *pSize){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  SQLITE_KV_LOG(("xFileSize('%s-journal')\n", pFile->zClass));
+  *pSize = pFile->nJrnl;
+  return SQLITE_OK;
+}
+static int kvvfsFileSizeDb(sqlite3_file *pProtoFile, sqlite_int64 *pSize){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  SQLITE_KV_LOG(("xFileSize('%s-db')\n", pFile->zClass));
+  if( pFile->szDb>=0 ){
+    *pSize = pFile->szDb;
+  }else{
+    *pSize = kvvfsReadFileSize(pFile);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Lock an kvvfs-file.
+*/
+static int kvvfsLock(sqlite3_file *pProtoFile, int eLock){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  assert( !pFile->isJournal );
+  SQLITE_KV_LOG(("xLock(%s,%d)\n", pFile->zClass, eLock));
+
+  if( eLock!=SQLITE_LOCK_NONE ){
+    pFile->szDb = kvvfsReadFileSize(pFile);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Unlock an kvvfs-file.
+*/
+static int kvvfsUnlock(sqlite3_file *pProtoFile, int eLock){
+  KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+  assert( !pFile->isJournal );
+  SQLITE_KV_LOG(("xUnlock(%s,%d)\n", pFile->zClass, eLock));
+  if( eLock==SQLITE_LOCK_NONE ){
+    pFile->szDb = -1;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on an kvvfs-file.
+*/
+static int kvvfsCheckReservedLock(sqlite3_file *pProtoFile, int *pResOut){
+  SQLITE_KV_LOG(("xCheckReservedLock\n"));
+  *pResOut = 0;
+  return SQLITE_OK;
+}
+
+/*
+** File control method. For custom operations on an kvvfs-file.
+*/
+static int kvvfsFileControlJrnl(sqlite3_file *pProtoFile, int op, void *pArg){
+  SQLITE_KV_LOG(("xFileControl(%d) on journal\n", op));
+  return SQLITE_NOTFOUND;
+}
+static int kvvfsFileControlDb(sqlite3_file *pProtoFile, int op, void *pArg){
+  SQLITE_KV_LOG(("xFileControl(%d) on database\n", op));
+  if( op==SQLITE_FCNTL_SYNC ){
+    KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+    int rc = SQLITE_OK;
+    SQLITE_KV_LOG(("xSync('%s-db')\n", pFile->zClass));
+    if( pFile->szDb>0 && 0!=kvvfsWriteFileSize(pFile, pFile->szDb) ){
+      rc = SQLITE_IOERR;
+    }
+    return rc;
+  }
+  return SQLITE_NOTFOUND;
+}
+
+/*
+** Return the sector-size in bytes for an kvvfs-file.
+*/
+static int kvvfsSectorSize(sqlite3_file *pFile){
+  return 512;
+}
+
+/*
+** Return the device characteristic flags supported by an kvvfs-file.
+*/
+static int kvvfsDeviceCharacteristics(sqlite3_file *pProtoFile){
+  return 0;
+}
+
+/****** sqlite3_vfs methods *************************************************/
+
+/*
+** Open an kvvfs file handle.
+*/
+static int kvvfsOpen(
+  sqlite3_vfs *pProtoVfs,
+  const char *zName,
+  sqlite3_file *pProtoFile,
+  int flags,
+  int *pOutFlags
+){
+  KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+  if( zName==0 ) zName = "";
+  SQLITE_KV_LOG(("xOpen(\"%s\")\n", zName));
+  if( strcmp(zName, "local")==0
+   || strcmp(zName, "session")==0
+  ){
+    pFile->isJournal = 0;
+    pFile->base.pMethods = &kvvfs_db_io_methods;
+  }else
+  if( strcmp(zName, "local-journal")==0
+   || strcmp(zName, "session-journal")==0
+  ){
+    pFile->isJournal = 1;
+    pFile->base.pMethods = &kvvfs_jrnl_io_methods;
+  }else{
+    return SQLITE_CANTOPEN;
+  }
+  if( zName[0]=='s' ){
+    pFile->zClass = "session";
+  }else{
+    pFile->zClass = "local";
+  }
+  pFile->aData = sqlite3_malloc64(SQLITE_KVOS_SZ);
+  if( pFile->aData==0 ){
+    return SQLITE_NOMEM;
+  }
+  pFile->aJrnl = 0;
+  pFile->nJrnl = 0;
+  pFile->szPage = -1;
+  pFile->szDb = -1;
+  return SQLITE_OK;
+}
+
+/*
+** Delete the file located at zPath. If the dirSync argument is true,
+** ensure the file-system modifications are synced to disk before
+** returning.
+*/
+static int kvvfsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  if( strcmp(zPath, "local-journal")==0 ){
+    sqlite3KvvfsMethods.xDelete("local", "jrnl");
+  }else
+  if( strcmp(zPath, "session-journal")==0 ){
+    sqlite3KvvfsMethods.xDelete("session", "jrnl");
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Test for access permissions. Return true if the requested permission
+** is available, or false otherwise.
+*/
+static int kvvfsAccess(
+  sqlite3_vfs *pProtoVfs,
+  const char *zPath,
+  int flags,
+  int *pResOut
+){
+  SQLITE_KV_LOG(("xAccess(\"%s\")\n", zPath));
+  if( strcmp(zPath, "local-journal")==0 ){
+    *pResOut = sqlite3KvvfsMethods.xRead("local", "jrnl", 0, 0)>0;
+  }else
+  if( strcmp(zPath, "session-journal")==0 ){
+    *pResOut = sqlite3KvvfsMethods.xRead("session", "jrnl", 0, 0)>0;
+  }else
+  if( strcmp(zPath, "local")==0 ){
+    *pResOut = sqlite3KvvfsMethods.xRead("local", "sz", 0, 0)>0;
+  }else
+  if( strcmp(zPath, "session")==0 ){
+    *pResOut = sqlite3KvvfsMethods.xRead("session", "sz", 0, 0)>0;
+  }else
+  {
+    *pResOut = 0;
+  }
+  SQLITE_KV_LOG(("xAccess returns %d\n",*pResOut));
+  return SQLITE_OK;
+}
+
+/*
+** Populate buffer zOut with the full canonical pathname corresponding
+** to the pathname in zPath. zOut is guaranteed to point to a buffer
+** of at least (INST_MAX_PATHNAME+1) bytes.
+*/
+static int kvvfsFullPathname(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int nOut,
+  char *zOut
+){
+  size_t nPath;
+#ifdef SQLITE_OS_KV_ALWAYS_LOCAL
+  zPath = "local";
+#endif
+  nPath = strlen(zPath);
+  SQLITE_KV_LOG(("xFullPathname(\"%s\")\n", zPath));
+  if( nOut<nPath+1 ) nPath = nOut - 1;
+  memcpy(zOut, zPath, nPath);
+  zOut[nPath] = 0;
+  return SQLITE_OK;
+}
+
+/*
+** Open the dynamic library located at zPath and return a handle.
+*/
+static void *kvvfsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  return 0;
+}
+
+/*
+** Populate the buffer pointed to by zBufOut with nByte bytes of
+** random data.
+*/
+static int kvvfsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  memset(zBufOut, 0, nByte);
+  return nByte;
+}
+
+/*
+** Sleep for nMicro microseconds. Return the number of microseconds
+** actually slept.
+*/
+static int kvvfsSleep(sqlite3_vfs *pVfs, int nMicro){
+  return SQLITE_OK;
+}
+
+/*
+** Return the current time as a Julian Day number in *pTimeOut.
+*/
+static int kvvfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+  sqlite3_int64 i = 0;
+  int rc;
+  rc = kvvfsCurrentTimeInt64(0, &i);
+  *pTimeOut = i/86400000.0;
+  return rc;
+}
+#include <sys/time.h>
+static int kvvfsCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
+  static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+  struct timeval sNow;
+  (void)gettimeofday(&sNow, 0);  /* Cannot fail given valid arguments */
+  *pTimeOut = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_usec/1000;
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OS_KV || SQLITE_OS_UNIX */
+
+#if SQLITE_OS_KV
+/*
+** This routine is called initialize the KV-vfs as the default VFS.
+*/
+SQLITE_API int sqlite3_os_init(void){
+  return sqlite3_vfs_register(&sqlite3OsKvvfsObject, 1);
+}
+SQLITE_API int sqlite3_os_end(void){
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OS_KV */
+
+#if SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL)
+SQLITE_PRIVATE int sqlite3KvvfsInit(void){
+  return sqlite3_vfs_register(&sqlite3OsKvvfsObject, 0);
+}
+#endif
+
+/************** End of os_kv.c ***********************************************/
+/************** Begin file os_unix.c *****************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains the VFS implementation for unix-like operating systems
+** include Linux, MacOSX, *BSD, QNX, VxWorks, AIX, HPUX, and others.
+**
+** There are actually several different VFS implementations in this file.
+** The differences are in the way that file locking is done.  The default
+** implementation uses Posix Advisory Locks.  Alternative implementations
+** use flock(), dot-files, various proprietary locking schemas, or simply
+** skip locking all together.
+**
+** This source file is organized into divisions where the logic for various
+** subfunctions is contained within the appropriate division.  PLEASE
+** KEEP THE STRUCTURE OF THIS FILE INTACT.  New code should be placed
+** in the correct division and should be clearly labelled.
+**
+** The layout of divisions is as follows:
+**
+**   *  General-purpose declarations and utility functions.
+**   *  Unique file ID logic used by VxWorks.
+**   *  Various locking primitive implementations (all except proxy locking):
+**      + for Posix Advisory Locks
+**      + for no-op locks
+**      + for dot-file locks
+**      + for flock() locking
+**      + for named semaphore locks (VxWorks only)
+**      + for AFP filesystem locks (MacOSX only)
+**   *  sqlite3_file methods not associated with locking.
+**   *  Definitions of sqlite3_io_methods objects for all locking
+**      methods plus "finder" functions for each locking method.
+**   *  sqlite3_vfs method implementations.
+**   *  Locking primitives for the proxy uber-locking-method. (MacOSX only)
+**   *  Definitions of sqlite3_vfs objects for all locking methods
+**      plus implementations of sqlite3_os_init() and sqlite3_os_end().
+*/
+/* #include "sqliteInt.h" */
+#if SQLITE_OS_UNIX              /* This file is used on unix only */
+
+/*
+** There are various methods for file locking used for concurrency
+** control:
+**
+**   1. POSIX locking (the default),
+**   2. No locking,
+**   3. Dot-file locking,
+**   4. flock() locking,
+**   5. AFP locking (OSX only),
+**   6. Named POSIX semaphores (VXWorks only),
+**   7. proxy locking. (OSX only)
+**
+** Styles 4, 5, and 7 are only available of SQLITE_ENABLE_LOCKING_STYLE
+** is defined to 1.  The SQLITE_ENABLE_LOCKING_STYLE also enables automatic
+** selection of the appropriate locking style based on the filesystem
+** where the database is located.
+*/
+#if !defined(SQLITE_ENABLE_LOCKING_STYLE)
+#  if defined(__APPLE__)
+#    define SQLITE_ENABLE_LOCKING_STYLE 1
+#  else
+#    define SQLITE_ENABLE_LOCKING_STYLE 0
+#  endif
+#endif
+
+/* Use pread() and pwrite() if they are available */
+#if defined(__APPLE__) || defined(__linux__)
+# define HAVE_PREAD 1
+# define HAVE_PWRITE 1
+#endif
+#if defined(HAVE_PREAD64) && defined(HAVE_PWRITE64)
+# undef USE_PREAD
+# define USE_PREAD64 1
+#elif defined(HAVE_PREAD) && defined(HAVE_PWRITE)
+# undef USE_PREAD64
+# define USE_PREAD 1
+#endif
+
+/*
+** standard include files.
+*/
+#include <sys/types.h>   /* amalgamator: keep */
+#include <sys/stat.h>    /* amalgamator: keep */
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <unistd.h>      /* amalgamator: keep */
+/* #include <time.h> */
+#include <sys/time.h>    /* amalgamator: keep */
+#include <errno.h>
+#if (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0) \
+  && !defined(SQLITE_WASI)
+# include <sys/mman.h>
+#endif
+
+#if SQLITE_ENABLE_LOCKING_STYLE
+/* # include <sys/ioctl.h> */
+# include <sys/file.h>
+# include <sys/param.h>
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+/*
+** Try to determine if gethostuuid() is available based on standard
+** macros.  This might sometimes compute the wrong value for some
+** obscure platforms.  For those cases, simply compile with one of
+** the following:
+**
+**    -DHAVE_GETHOSTUUID=0
+**    -DHAVE_GETHOSTUUID=1
+**
+** None if this matters except when building on Apple products with
+** -DSQLITE_ENABLE_LOCKING_STYLE.
+*/
+#ifndef HAVE_GETHOSTUUID
+# define HAVE_GETHOSTUUID 0
+# if defined(__APPLE__) && ((__MAC_OS_X_VERSION_MIN_REQUIRED > 1050) || \
+                            (__IPHONE_OS_VERSION_MIN_REQUIRED > 2000))
+#    if (!defined(TARGET_OS_EMBEDDED) || (TARGET_OS_EMBEDDED==0)) \
+        && (!defined(TARGET_IPHONE_SIMULATOR) || (TARGET_IPHONE_SIMULATOR==0))\
+        && (!defined(TARGET_OS_MACCATALYST) || (TARGET_OS_MACCATALYST==0))
+#      undef HAVE_GETHOSTUUID
+#      define HAVE_GETHOSTUUID 1
+#    else
+#      warning "gethostuuid() is disabled."
+#    endif
+#  endif
+#endif
+
+
+#if OS_VXWORKS
+/* # include <sys/ioctl.h> */
+# include <semaphore.h>
+# include <limits.h>
+#endif /* OS_VXWORKS */
+
+#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
+# include <sys/mount.h>
+#endif
+
+#ifdef HAVE_UTIME
+# include <utime.h>
+#endif
+
+/*
+** Allowed values of unixFile.fsFlags
+*/
+#define SQLITE_FSFLAGS_IS_MSDOS     0x1
+
+/*
+** If we are to be thread-safe, include the pthreads header.
+*/
+#if SQLITE_THREADSAFE
+/* # include <pthread.h> */
+#endif
+
+/*
+** Default permissions when creating a new file
+*/
+#ifndef SQLITE_DEFAULT_FILE_PERMISSIONS
+# define SQLITE_DEFAULT_FILE_PERMISSIONS 0644
+#endif
+
+/*
+** Default permissions when creating auto proxy dir
+*/
+#ifndef SQLITE_DEFAULT_PROXYDIR_PERMISSIONS
+# define SQLITE_DEFAULT_PROXYDIR_PERMISSIONS 0755
+#endif
+
+/*
+** Maximum supported path-length.
+*/
+#define MAX_PATHNAME 512
+
+/*
+** Maximum supported symbolic links
+*/
+#define SQLITE_MAX_SYMLINKS 100
+
+/*
+** Remove and stub certain info for WASI (WebAssembly System
+** Interface) builds.
+*/
+#ifdef SQLITE_WASI
+# undef HAVE_FCHMOD
+# undef HAVE_FCHOWN
+# undef HAVE_MREMAP
+# define HAVE_MREMAP 0
+# ifndef SQLITE_DEFAULT_UNIX_VFS
+#  define SQLITE_DEFAULT_UNIX_VFS "unix-dotfile"
+   /* ^^^ should SQLITE_DEFAULT_UNIX_VFS be "unix-none"? */
+# endif
+# ifndef F_RDLCK
+#  define F_RDLCK 0
+#  define F_WRLCK 1
+#  define F_UNLCK 2
+#  if __LONG_MAX == 0x7fffffffL
+#   define F_GETLK 12
+#   define F_SETLK 13
+#   define F_SETLKW 14
+#  else
+#   define F_GETLK 5
+#   define F_SETLK 6
+#   define F_SETLKW 7
+#  endif
+# endif
+#else /* !SQLITE_WASI */
+# ifndef HAVE_FCHMOD
+#  define HAVE_FCHMOD 1
+# endif
+#endif /* SQLITE_WASI */
+
+#ifdef SQLITE_WASI
+# define osGetpid(X) (pid_t)1
+#else
+/* Always cast the getpid() return type for compatibility with
+** kernel modules in VxWorks. */
+# define osGetpid(X) (pid_t)getpid()
+#endif
+
+/*
+** Only set the lastErrno if the error code is a real error and not
+** a normal expected return code of SQLITE_BUSY or SQLITE_OK
+*/
+#define IS_LOCK_ERROR(x)  ((x != SQLITE_OK) && (x != SQLITE_BUSY))
+
+/* Forward references */
+typedef struct unixShm unixShm;               /* Connection shared memory */
+typedef struct unixShmNode unixShmNode;       /* Shared memory instance */
+typedef struct unixInodeInfo unixInodeInfo;   /* An i-node */
+typedef struct UnixUnusedFd UnixUnusedFd;     /* An unused file descriptor */
+
+/*
+** Sometimes, after a file handle is closed by SQLite, the file descriptor
+** cannot be closed immediately. In these cases, instances of the following
+** structure are used to store the file descriptor while waiting for an
+** opportunity to either close or reuse it.
+*/
+struct UnixUnusedFd {
+  int fd;                   /* File descriptor to close */
+  int flags;                /* Flags this file descriptor was opened with */
+  UnixUnusedFd *pNext;      /* Next unused file descriptor on same file */
+};
+
+/*
+** The unixFile structure is subclass of sqlite3_file specific to the unix
+** VFS implementations.
+*/
+typedef struct unixFile unixFile;
+struct unixFile {
+  sqlite3_io_methods const *pMethod;  /* Always the first entry */
+  sqlite3_vfs *pVfs;                  /* The VFS that created this unixFile */
+  unixInodeInfo *pInode;              /* Info about locks on this inode */
+  int h;                              /* The file descriptor */
+  unsigned char eFileLock;            /* The type of lock held on this fd */
+  unsigned short int ctrlFlags;       /* Behavioral bits.  UNIXFILE_* flags */
+  int lastErrno;                      /* The unix errno from last I/O error */
+  void *lockingContext;               /* Locking style specific state */
+  UnixUnusedFd *pPreallocatedUnused;  /* Pre-allocated UnixUnusedFd */
+  const char *zPath;                  /* Name of the file */
+  unixShm *pShm;                      /* Shared memory segment information */
+  int szChunk;                        /* Configured by FCNTL_CHUNK_SIZE */
+#if SQLITE_MAX_MMAP_SIZE>0
+  int nFetchOut;                      /* Number of outstanding xFetch refs */
+  sqlite3_int64 mmapSize;             /* Usable size of mapping at pMapRegion */
+  sqlite3_int64 mmapSizeActual;       /* Actual size of mapping at pMapRegion */
+  sqlite3_int64 mmapSizeMax;          /* Configured FCNTL_MMAP_SIZE value */
+  void *pMapRegion;                   /* Memory mapped region */
+#endif
+  int sectorSize;                     /* Device sector size */
+  int deviceCharacteristics;          /* Precomputed device characteristics */
+#if SQLITE_ENABLE_LOCKING_STYLE
+  int openFlags;                      /* The flags specified at open() */
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
+  unsigned fsFlags;                   /* cached details from statfs() */
+#endif
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  unsigned iBusyTimeout;              /* Wait this many millisec on locks */
+#endif
+#if OS_VXWORKS
+  struct vxworksFileId *pId;          /* Unique file ID */
+#endif
+#ifdef SQLITE_DEBUG
+  /* The next group of variables are used to track whether or not the
+  ** transaction counter in bytes 24-27 of database files are updated
+  ** whenever any part of the database changes.  An assertion fault will
+  ** occur if a file is updated without also updating the transaction
+  ** counter.  This test is made to avoid new problems similar to the
+  ** one described by ticket #3584.
+  */
+  unsigned char transCntrChng;   /* True if the transaction counter changed */
+  unsigned char dbUpdate;        /* True if any part of database file changed */
+  unsigned char inNormalWrite;   /* True if in a normal write operation */
+
+#endif
+
+#ifdef SQLITE_TEST
+  /* In test mode, increase the size of this structure a bit so that
+  ** it is larger than the struct CrashFile defined in test6.c.
+  */
+  char aPadding[32];
+#endif
+};
+
+/* This variable holds the process id (pid) from when the xRandomness()
+** method was called.  If xOpen() is called from a different process id,
+** indicating that a fork() has occurred, the PRNG will be reset.
+*/
+static pid_t randomnessPid = 0;
+
+/*
+** Allowed values for the unixFile.ctrlFlags bitmask:
+*/
+#define UNIXFILE_EXCL        0x01     /* Connections from one process only */
+#define UNIXFILE_RDONLY      0x02     /* Connection is read only */
+#define UNIXFILE_PERSIST_WAL 0x04     /* Persistent WAL mode */
+#if !defined(SQLITE_DISABLE_DIRSYNC) && !defined(_AIX)
+# define UNIXFILE_DIRSYNC    0x08     /* Directory sync needed */
+#else
+# define UNIXFILE_DIRSYNC    0x00
+#endif
+#define UNIXFILE_PSOW        0x10     /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
+#define UNIXFILE_DELETE      0x20     /* Delete on close */
+#define UNIXFILE_URI         0x40     /* Filename might have query parameters */
+#define UNIXFILE_NOLOCK      0x80     /* Do no file locking */
+
+/*
+** Include code that is common to all os_*.c files
+*/
+/* #include "os_common.h" */
+
+/*
+** Define various macros that are missing from some systems.
+*/
+#ifndef O_LARGEFILE
+# define O_LARGEFILE 0
+#endif
+#ifdef SQLITE_DISABLE_LFS
+# undef O_LARGEFILE
+# define O_LARGEFILE 0
+#endif
+#ifndef O_NOFOLLOW
+# define O_NOFOLLOW 0
+#endif
+#ifndef O_BINARY
+# define O_BINARY 0
+#endif
+
+/*
+** The threadid macro resolves to the thread-id or to 0.  Used for
+** testing and debugging only.
+*/
+#if SQLITE_THREADSAFE
+#define threadid pthread_self()
+#else
+#define threadid 0
+#endif
+
+/*
+** HAVE_MREMAP defaults to true on Linux and false everywhere else.
+*/
+#if !defined(HAVE_MREMAP)
+# if defined(__linux__) && defined(_GNU_SOURCE)
+#  define HAVE_MREMAP 1
+# else
+#  define HAVE_MREMAP 0
+# endif
+#endif
+
+/*
+** Explicitly call the 64-bit version of lseek() on Android. Otherwise, lseek()
+** is the 32-bit version, even if _FILE_OFFSET_BITS=64 is defined.
+*/
+#ifdef __ANDROID__
+# define lseek lseek64
+#endif
+
+#ifdef __linux__
+/*
+** Linux-specific IOCTL magic numbers used for controlling F2FS
+*/
+#define F2FS_IOCTL_MAGIC        0xf5
+#define F2FS_IOC_START_ATOMIC_WRITE     _IO(F2FS_IOCTL_MAGIC, 1)
+#define F2FS_IOC_COMMIT_ATOMIC_WRITE    _IO(F2FS_IOCTL_MAGIC, 2)
+#define F2FS_IOC_START_VOLATILE_WRITE   _IO(F2FS_IOCTL_MAGIC, 3)
+#define F2FS_IOC_ABORT_VOLATILE_WRITE   _IO(F2FS_IOCTL_MAGIC, 5)
+#define F2FS_IOC_GET_FEATURES           _IOR(F2FS_IOCTL_MAGIC, 12, u32)
+#define F2FS_FEATURE_ATOMIC_WRITE 0x0004
+#endif /* __linux__ */
+
+
+/*
+** Different Unix systems declare open() in different ways.  Same use
+** open(const char*,int,mode_t).  Others use open(const char*,int,...).
+** The difference is important when using a pointer to the function.
+**
+** The safest way to deal with the problem is to always use this wrapper
+** which always has the same well-defined interface.
+*/
+static int posixOpen(const char *zFile, int flags, int mode){
+  return open(zFile, flags, mode);
+}
+
+/* Forward reference */
+static int openDirectory(const char*, int*);
+static int unixGetpagesize(void);
+
+/*
+** Many system calls are accessed through pointer-to-functions so that
+** they may be overridden at runtime to facilitate fault injection during
+** testing and sandboxing.  The following array holds the names and pointers
+** to all overrideable system calls.
+*/
+static struct unix_syscall {
+  const char *zName;            /* Name of the system call */
+  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
+  sqlite3_syscall_ptr pDefault; /* Default value */
+} aSyscall[] = {
+  { "open",         (sqlite3_syscall_ptr)posixOpen,  0  },
+#define osOpen      ((int(*)(const char*,int,int))aSyscall[0].pCurrent)
+
+  { "close",        (sqlite3_syscall_ptr)close,      0  },
+#define osClose     ((int(*)(int))aSyscall[1].pCurrent)
+
+  { "access",       (sqlite3_syscall_ptr)access,     0  },
+#define osAccess    ((int(*)(const char*,int))aSyscall[2].pCurrent)
+
+  { "getcwd",       (sqlite3_syscall_ptr)getcwd,     0  },
+#define osGetcwd    ((char*(*)(char*,size_t))aSyscall[3].pCurrent)
+
+  { "stat",         (sqlite3_syscall_ptr)stat,       0  },
+#define osStat      ((int(*)(const char*,struct stat*))aSyscall[4].pCurrent)
+
+/*
+** The DJGPP compiler environment looks mostly like Unix, but it
+** lacks the fcntl() system call.  So redefine fcntl() to be something
+** that always succeeds.  This means that locking does not occur under
+** DJGPP.  But it is DOS - what did you expect?
+*/
+#ifdef __DJGPP__
+  { "fstat",        0,                 0  },
+#define osFstat(a,b,c)    0
+#else
+  { "fstat",        (sqlite3_syscall_ptr)fstat,      0  },
+#define osFstat     ((int(*)(int,struct stat*))aSyscall[5].pCurrent)
+#endif
+
+  { "ftruncate",    (sqlite3_syscall_ptr)ftruncate,  0  },
+#define osFtruncate ((int(*)(int,off_t))aSyscall[6].pCurrent)
+
+  { "fcntl",        (sqlite3_syscall_ptr)fcntl,      0  },
+#define osFcntl     ((int(*)(int,int,...))aSyscall[7].pCurrent)
+
+  { "read",         (sqlite3_syscall_ptr)read,       0  },
+#define osRead      ((ssize_t(*)(int,void*,size_t))aSyscall[8].pCurrent)
+
+#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE
+  { "pread",        (sqlite3_syscall_ptr)pread,      0  },
+#else
+  { "pread",        (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPread     ((ssize_t(*)(int,void*,size_t,off_t))aSyscall[9].pCurrent)
+
+#if defined(USE_PREAD64)
+  { "pread64",      (sqlite3_syscall_ptr)pread64,    0  },
+#else
+  { "pread64",      (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPread64 ((ssize_t(*)(int,void*,size_t,off64_t))aSyscall[10].pCurrent)
+
+  { "write",        (sqlite3_syscall_ptr)write,      0  },
+#define osWrite     ((ssize_t(*)(int,const void*,size_t))aSyscall[11].pCurrent)
+
+#if defined(USE_PREAD) || SQLITE_ENABLE_LOCKING_STYLE
+  { "pwrite",       (sqlite3_syscall_ptr)pwrite,     0  },
+#else
+  { "pwrite",       (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPwrite    ((ssize_t(*)(int,const void*,size_t,off_t))\
+                    aSyscall[12].pCurrent)
+
+#if defined(USE_PREAD64)
+  { "pwrite64",     (sqlite3_syscall_ptr)pwrite64,   0  },
+#else
+  { "pwrite64",     (sqlite3_syscall_ptr)0,          0  },
+#endif
+#define osPwrite64  ((ssize_t(*)(int,const void*,size_t,off64_t))\
+                    aSyscall[13].pCurrent)
+
+#if defined(HAVE_FCHMOD)
+  { "fchmod",       (sqlite3_syscall_ptr)fchmod,          0  },
+#else
+  { "fchmod",       (sqlite3_syscall_ptr)0,               0  },
+#endif
+#define osFchmod    ((int(*)(int,mode_t))aSyscall[14].pCurrent)
+
+#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE
+  { "fallocate",    (sqlite3_syscall_ptr)posix_fallocate,  0 },
+#else
+  { "fallocate",    (sqlite3_syscall_ptr)0,                0 },
+#endif
+#define osFallocate ((int(*)(int,off_t,off_t))aSyscall[15].pCurrent)
+
+  { "unlink",       (sqlite3_syscall_ptr)unlink,           0 },
+#define osUnlink    ((int(*)(const char*))aSyscall[16].pCurrent)
+
+  { "openDirectory",    (sqlite3_syscall_ptr)openDirectory,      0 },
+#define osOpenDirectory ((int(*)(const char*,int*))aSyscall[17].pCurrent)
+
+  { "mkdir",        (sqlite3_syscall_ptr)mkdir,           0 },
+#define osMkdir     ((int(*)(const char*,mode_t))aSyscall[18].pCurrent)
+
+  { "rmdir",        (sqlite3_syscall_ptr)rmdir,           0 },
+#define osRmdir     ((int(*)(const char*))aSyscall[19].pCurrent)
+
+#if defined(HAVE_FCHOWN)
+  { "fchown",       (sqlite3_syscall_ptr)fchown,          0 },
+#else
+  { "fchown",       (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osFchown    ((int(*)(int,uid_t,gid_t))aSyscall[20].pCurrent)
+
+#if defined(HAVE_FCHOWN)
+  { "geteuid",      (sqlite3_syscall_ptr)geteuid,         0 },
+#else
+  { "geteuid",      (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osGeteuid   ((uid_t(*)(void))aSyscall[21].pCurrent)
+
+#if (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0) \
+  && !defined(SQLITE_WASI)
+  { "mmap",         (sqlite3_syscall_ptr)mmap,            0 },
+#else
+  { "mmap",         (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osMmap ((void*(*)(void*,size_t,int,int,int,off_t))aSyscall[22].pCurrent)
+
+#if (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0) \
+  && !defined(SQLITE_WASI)
+  { "munmap",       (sqlite3_syscall_ptr)munmap,          0 },
+#else
+  { "munmap",       (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osMunmap ((int(*)(void*,size_t))aSyscall[23].pCurrent)
+
+#if HAVE_MREMAP && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
+  { "mremap",       (sqlite3_syscall_ptr)mremap,          0 },
+#else
+  { "mremap",       (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osMremap ((void*(*)(void*,size_t,size_t,int,...))aSyscall[24].pCurrent)
+
+#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
+  { "getpagesize",  (sqlite3_syscall_ptr)unixGetpagesize, 0 },
+#else
+  { "getpagesize",  (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osGetpagesize ((int(*)(void))aSyscall[25].pCurrent)
+
+#if defined(HAVE_READLINK)
+  { "readlink",     (sqlite3_syscall_ptr)readlink,        0 },
+#else
+  { "readlink",     (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osReadlink ((ssize_t(*)(const char*,char*,size_t))aSyscall[26].pCurrent)
+
+#if defined(HAVE_LSTAT)
+  { "lstat",         (sqlite3_syscall_ptr)lstat,          0 },
+#else
+  { "lstat",         (sqlite3_syscall_ptr)0,              0 },
+#endif
+#define osLstat      ((int(*)(const char*,struct stat*))aSyscall[27].pCurrent)
+
+#if defined(__linux__) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+# ifdef __ANDROID__
+  { "ioctl", (sqlite3_syscall_ptr)(int(*)(int, int, ...))ioctl, 0 },
+#define osIoctl ((int(*)(int,int,...))aSyscall[28].pCurrent)
+# else
+  { "ioctl",         (sqlite3_syscall_ptr)ioctl,          0 },
+#define osIoctl ((int(*)(int,unsigned long,...))aSyscall[28].pCurrent)
+# endif
+#else
+  { "ioctl",         (sqlite3_syscall_ptr)0,              0 },
+#endif
+
+}; /* End of the overrideable system calls */
+
+
+/*
+** On some systems, calls to fchown() will trigger a message in a security
+** log if they come from non-root processes.  So avoid calling fchown() if
+** we are not running as root.
+*/
+static int robustFchown(int fd, uid_t uid, gid_t gid){
+#if defined(HAVE_FCHOWN)
+  return osGeteuid() ? 0 : osFchown(fd,uid,gid);
+#else
+  return 0;
+#endif
+}
+
+/*
+** This is the xSetSystemCall() method of sqlite3_vfs for all of the
+** "unix" VFSes.  Return SQLITE_OK upon successfully updating the
+** system call pointer, or SQLITE_NOTFOUND if there is no configurable
+** system call named zName.
+*/
+static int unixSetSystemCall(
+  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
+  const char *zName,            /* Name of system call to override */
+  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */
+){
+  unsigned int i;
+  int rc = SQLITE_NOTFOUND;
+
+  UNUSED_PARAMETER(pNotUsed);
+  if( zName==0 ){
+    /* If no zName is given, restore all system calls to their default
+    ** settings and return NULL
+    */
+    rc = SQLITE_OK;
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( aSyscall[i].pDefault ){
+        aSyscall[i].pCurrent = aSyscall[i].pDefault;
+      }
+    }
+  }else{
+    /* If zName is specified, operate on only the one system call
+    ** specified.
+    */
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ){
+        if( aSyscall[i].pDefault==0 ){
+          aSyscall[i].pDefault = aSyscall[i].pCurrent;
+        }
+        rc = SQLITE_OK;
+        if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault;
+        aSyscall[i].pCurrent = pNewFunc;
+        break;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the value of a system call.  Return NULL if zName is not a
+** recognized system call name.  NULL is also returned if the system call
+** is currently undefined.
+*/
+static sqlite3_syscall_ptr unixGetSystemCall(
+  sqlite3_vfs *pNotUsed,
+  const char *zName
+){
+  unsigned int i;
+
+  UNUSED_PARAMETER(pNotUsed);
+  for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+    if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent;
+  }
+  return 0;
+}
+
+/*
+** Return the name of the first system call after zName.  If zName==NULL
+** then return the name of the first system call.  Return NULL if zName
+** is the last system call or if zName is not the name of a valid
+** system call.
+*/
+static const char *unixNextSystemCall(sqlite3_vfs *p, const char *zName){
+  int i = -1;
+
+  UNUSED_PARAMETER(p);
+  if( zName ){
+    for(i=0; i<ArraySize(aSyscall)-1; i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ) break;
+    }
+  }
+  for(i++; i<ArraySize(aSyscall); i++){
+    if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName;
+  }
+  return 0;
+}
+
+/*
+** Do not accept any file descriptor less than this value, in order to avoid
+** opening database file using file descriptors that are commonly used for
+** standard input, output, and error.
+*/
+#ifndef SQLITE_MINIMUM_FILE_DESCRIPTOR
+# define SQLITE_MINIMUM_FILE_DESCRIPTOR 3
+#endif
+
+/*
+** Invoke open().  Do so multiple times, until it either succeeds or
+** fails for some reason other than EINTR.
+**
+** If the file creation mode "m" is 0 then set it to the default for
+** SQLite.  The default is SQLITE_DEFAULT_FILE_PERMISSIONS (normally
+** 0644) as modified by the system umask.  If m is not 0, then
+** make the file creation mode be exactly m ignoring the umask.
+**
+** The m parameter will be non-zero only when creating -wal, -journal,
+** and -shm files.  We want those files to have *exactly* the same
+** permissions as their original database, unadulterated by the umask.
+** In that way, if a database file is -rw-rw-rw or -rw-rw-r-, and a
+** transaction crashes and leaves behind hot journals, then any
+** process that is able to write to the database will also be able to
+** recover the hot journals.
+*/
+static int robust_open(const char *z, int f, mode_t m){
+  int fd;
+  mode_t m2 = m ? m : SQLITE_DEFAULT_FILE_PERMISSIONS;
+  while(1){
+#if defined(O_CLOEXEC)
+    fd = osOpen(z,f|O_CLOEXEC,m2);
+#else
+    fd = osOpen(z,f,m2);
+#endif
+    if( fd<0 ){
+      if( errno==EINTR ) continue;
+      break;
+    }
+    if( fd>=SQLITE_MINIMUM_FILE_DESCRIPTOR ) break;
+    if( (f & (O_EXCL|O_CREAT))==(O_EXCL|O_CREAT) ){
+      (void)osUnlink(z);
+    }
+    osClose(fd);
+    sqlite3_log(SQLITE_WARNING,
+                "attempt to open \"%s\" as file descriptor %d", z, fd);
+    fd = -1;
+    if( osOpen("/dev/null", O_RDONLY, m)<0 ) break;
+  }
+  if( fd>=0 ){
+    if( m!=0 ){
+      struct stat statbuf;
+      if( osFstat(fd, &statbuf)==0
+       && statbuf.st_size==0
+       && (statbuf.st_mode&0777)!=m
+      ){
+        osFchmod(fd, m);
+      }
+    }
+#if defined(FD_CLOEXEC) && (!defined(O_CLOEXEC) || O_CLOEXEC==0)
+    osFcntl(fd, F_SETFD, osFcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
+#endif
+  }
+  return fd;
+}
+
+/*
+** Helper functions to obtain and relinquish the global mutex. The
+** global mutex is used to protect the unixInodeInfo and
+** vxworksFileId objects used by this file, all of which may be
+** shared by multiple threads.
+**
+** Function unixMutexHeld() is used to assert() that the global mutex
+** is held when required. This function is only used as part of assert()
+** statements. e.g.
+**
+**   unixEnterMutex()
+**     assert( unixMutexHeld() );
+**   unixEnterLeave()
+**
+** To prevent deadlock, the global unixBigLock must must be acquired
+** before the unixInodeInfo.pLockMutex mutex, if both are held.  It is
+** OK to get the pLockMutex without holding unixBigLock first, but if
+** that happens, the unixBigLock mutex must not be acquired until after
+** pLockMutex is released.
+**
+**      OK:     enter(unixBigLock),  enter(pLockInfo)
+**      OK:     enter(unixBigLock)
+**      OK:     enter(pLockInfo)
+**   ERROR:     enter(pLockInfo), enter(unixBigLock)
+*/
+static sqlite3_mutex *unixBigLock = 0;
+static void unixEnterMutex(void){
+  assert( sqlite3_mutex_notheld(unixBigLock) );  /* Not a recursive mutex */
+  sqlite3_mutex_enter(unixBigLock);
+}
+static void unixLeaveMutex(void){
+  assert( sqlite3_mutex_held(unixBigLock) );
+  sqlite3_mutex_leave(unixBigLock);
+}
+#ifdef SQLITE_DEBUG
+static int unixMutexHeld(void) {
+  return sqlite3_mutex_held(unixBigLock);
+}
+#endif
+
+
+#ifdef SQLITE_HAVE_OS_TRACE
+/*
+** Helper function for printing out trace information from debugging
+** binaries. This returns the string representation of the supplied
+** integer lock-type.
+*/
+static const char *azFileLock(int eFileLock){
+  switch( eFileLock ){
+    case NO_LOCK: return "NONE";
+    case SHARED_LOCK: return "SHARED";
+    case RESERVED_LOCK: return "RESERVED";
+    case PENDING_LOCK: return "PENDING";
+    case EXCLUSIVE_LOCK: return "EXCLUSIVE";
+  }
+  return "ERROR";
+}
+#endif
+
+#ifdef SQLITE_LOCK_TRACE
+/*
+** Print out information about all locking operations.
+**
+** This routine is used for troubleshooting locks on multithreaded
+** platforms.  Enable by compiling with the -DSQLITE_LOCK_TRACE
+** command-line option on the compiler.  This code is normally
+** turned off.
+*/
+static int lockTrace(int fd, int op, struct flock *p){
+  char *zOpName, *zType;
+  int s;
+  int savedErrno;
+  if( op==F_GETLK ){
+    zOpName = "GETLK";
+  }else if( op==F_SETLK ){
+    zOpName = "SETLK";
+  }else{
+    s = osFcntl(fd, op, p);
+    sqlite3DebugPrintf("fcntl unknown %d %d %d\n", fd, op, s);
+    return s;
+  }
+  if( p->l_type==F_RDLCK ){
+    zType = "RDLCK";
+  }else if( p->l_type==F_WRLCK ){
+    zType = "WRLCK";
+  }else if( p->l_type==F_UNLCK ){
+    zType = "UNLCK";
+  }else{
+    assert( 0 );
+  }
+  assert( p->l_whence==SEEK_SET );
+  s = osFcntl(fd, op, p);
+  savedErrno = errno;
+  sqlite3DebugPrintf("fcntl %d %d %s %s %d %d %d %d\n",
+     threadid, fd, zOpName, zType, (int)p->l_start, (int)p->l_len,
+     (int)p->l_pid, s);
+  if( s==(-1) && op==F_SETLK && (p->l_type==F_RDLCK || p->l_type==F_WRLCK) ){
+    struct flock l2;
+    l2 = *p;
+    osFcntl(fd, F_GETLK, &l2);
+    if( l2.l_type==F_RDLCK ){
+      zType = "RDLCK";
+    }else if( l2.l_type==F_WRLCK ){
+      zType = "WRLCK";
+    }else if( l2.l_type==F_UNLCK ){
+      zType = "UNLCK";
+    }else{
+      assert( 0 );
+    }
+    sqlite3DebugPrintf("fcntl-failure-reason: %s %d %d %d\n",
+       zType, (int)l2.l_start, (int)l2.l_len, (int)l2.l_pid);
+  }
+  errno = savedErrno;
+  return s;
+}
+#undef osFcntl
+#define osFcntl lockTrace
+#endif /* SQLITE_LOCK_TRACE */
+
+/*
+** Retry ftruncate() calls that fail due to EINTR
+**
+** All calls to ftruncate() within this file should be made through
+** this wrapper.  On the Android platform, bypassing the logic below
+** could lead to a corrupt database.
+*/
+static int robust_ftruncate(int h, sqlite3_int64 sz){
+  int rc;
+#ifdef __ANDROID__
+  /* On Android, ftruncate() always uses 32-bit offsets, even if
+  ** _FILE_OFFSET_BITS=64 is defined. This means it is unsafe to attempt to
+  ** truncate a file to any size larger than 2GiB. Silently ignore any
+  ** such attempts.  */
+  if( sz>(sqlite3_int64)0x7FFFFFFF ){
+    rc = SQLITE_OK;
+  }else
+#endif
+  do{ rc = osFtruncate(h,sz); }while( rc<0 && errno==EINTR );
+  return rc;
+}
+
+/*
+** This routine translates a standard POSIX errno code into something
+** useful to the clients of the sqlite3 functions.  Specifically, it is
+** intended to translate a variety of "try again" errors into SQLITE_BUSY
+** and a variety of "please close the file descriptor NOW" errors into
+** SQLITE_IOERR
+**
+** Errors during initialization of locks, or file system support for locks,
+** should handle ENOLCK, ENOTSUP, EOPNOTSUPP separately.
+*/
+static int sqliteErrorFromPosixError(int posixError, int sqliteIOErr) {
+  assert( (sqliteIOErr == SQLITE_IOERR_LOCK) ||
+          (sqliteIOErr == SQLITE_IOERR_UNLOCK) ||
+          (sqliteIOErr == SQLITE_IOERR_RDLOCK) ||
+          (sqliteIOErr == SQLITE_IOERR_CHECKRESERVEDLOCK) );
+  switch (posixError) {
+  case EACCES:
+  case EAGAIN:
+  case ETIMEDOUT:
+  case EBUSY:
+  case EINTR:
+  case ENOLCK:
+    /* random NFS retry error, unless during file system support
+     * introspection, in which it actually means what it says */
+    return SQLITE_BUSY;
+
+  case EPERM:
+    return SQLITE_PERM;
+
+  default:
+    return sqliteIOErr;
+  }
+}
+
+
+/******************************************************************************
+****************** Begin Unique File ID Utility Used By VxWorks ***************
+**
+** On most versions of unix, we can get a unique ID for a file by concatenating
+** the device number and the inode number.  But this does not work on VxWorks.
+** On VxWorks, a unique file id must be based on the canonical filename.
+**
+** A pointer to an instance of the following structure can be used as a
+** unique file ID in VxWorks.  Each instance of this structure contains
+** a copy of the canonical filename.  There is also a reference count.
+** The structure is reclaimed when the number of pointers to it drops to
+** zero.
+**
+** There are never very many files open at one time and lookups are not
+** a performance-critical path, so it is sufficient to put these
+** structures on a linked list.
+*/
+struct vxworksFileId {
+  struct vxworksFileId *pNext;  /* Next in a list of them all */
+  int nRef;                     /* Number of references to this one */
+  int nName;                    /* Length of the zCanonicalName[] string */
+  char *zCanonicalName;         /* Canonical filename */
+};
+
+#if OS_VXWORKS
+/*
+** All unique filenames are held on a linked list headed by this
+** variable:
+*/
+static struct vxworksFileId *vxworksFileList = 0;
+
+/*
+** Simplify a filename into its canonical form
+** by making the following changes:
+**
+**  * removing any trailing and duplicate /
+**  * convert /./ into just /
+**  * convert /A/../ where A is any simple name into just /
+**
+** Changes are made in-place.  Return the new name length.
+**
+** The original filename is in z[0..n-1].  Return the number of
+** characters in the simplified name.
+*/
+static int vxworksSimplifyName(char *z, int n){
+  int i, j;
+  while( n>1 && z[n-1]=='/' ){ n--; }
+  for(i=j=0; i<n; i++){
+    if( z[i]=='/' ){
+      if( z[i+1]=='/' ) continue;
+      if( z[i+1]=='.' && i+2<n && z[i+2]=='/' ){
+        i += 1;
+        continue;
+      }
+      if( z[i+1]=='.' && i+3<n && z[i+2]=='.' && z[i+3]=='/' ){
+        while( j>0 && z[j-1]!='/' ){ j--; }
+        if( j>0 ){ j--; }
+        i += 2;
+        continue;
+      }
+    }
+    z[j++] = z[i];
+  }
+  z[j] = 0;
+  return j;
+}
+
+/*
+** Find a unique file ID for the given absolute pathname.  Return
+** a pointer to the vxworksFileId object.  This pointer is the unique
+** file ID.
+**
+** The nRef field of the vxworksFileId object is incremented before
+** the object is returned.  A new vxworksFileId object is created
+** and added to the global list if necessary.
+**
+** If a memory allocation error occurs, return NULL.
+*/
+static struct vxworksFileId *vxworksFindFileId(const char *zAbsoluteName){
+  struct vxworksFileId *pNew;         /* search key and new file ID */
+  struct vxworksFileId *pCandidate;   /* For looping over existing file IDs */
+  int n;                              /* Length of zAbsoluteName string */
+
+  assert( zAbsoluteName[0]=='/' );
+  n = (int)strlen(zAbsoluteName);
+  pNew = sqlite3_malloc64( sizeof(*pNew) + (n+1) );
+  if( pNew==0 ) return 0;
+  pNew->zCanonicalName = (char*)&pNew[1];
+  memcpy(pNew->zCanonicalName, zAbsoluteName, n+1);
+  n = vxworksSimplifyName(pNew->zCanonicalName, n);
+
+  /* Search for an existing entry that matching the canonical name.
+  ** If found, increment the reference count and return a pointer to
+  ** the existing file ID.
+  */
+  unixEnterMutex();
+  for(pCandidate=vxworksFileList; pCandidate; pCandidate=pCandidate->pNext){
+    if( pCandidate->nName==n
+     && memcmp(pCandidate->zCanonicalName, pNew->zCanonicalName, n)==0
+    ){
+       sqlite3_free(pNew);
+       pCandidate->nRef++;
+       unixLeaveMutex();
+       return pCandidate;
+    }
+  }
+
+  /* No match was found.  We will make a new file ID */
+  pNew->nRef = 1;
+  pNew->nName = n;
+  pNew->pNext = vxworksFileList;
+  vxworksFileList = pNew;
+  unixLeaveMutex();
+  return pNew;
+}
+
+/*
+** Decrement the reference count on a vxworksFileId object.  Free
+** the object when the reference count reaches zero.
+*/
+static void vxworksReleaseFileId(struct vxworksFileId *pId){
+  unixEnterMutex();
+  assert( pId->nRef>0 );
+  pId->nRef--;
+  if( pId->nRef==0 ){
+    struct vxworksFileId **pp;
+    for(pp=&vxworksFileList; *pp && *pp!=pId; pp = &((*pp)->pNext)){}
+    assert( *pp==pId );
+    *pp = pId->pNext;
+    sqlite3_free(pId);
+  }
+  unixLeaveMutex();
+}
+#endif /* OS_VXWORKS */
+/*************** End of Unique File ID Utility Used By VxWorks ****************
+******************************************************************************/
+
+
+/******************************************************************************
+*************************** Posix Advisory Locking ****************************
+**
+** POSIX advisory locks are broken by design.  ANSI STD 1003.1 (1996)
+** section 6.5.2.2 lines 483 through 490 specify that when a process
+** sets or clears a lock, that operation overrides any prior locks set
+** by the same process.  It does not explicitly say so, but this implies
+** that it overrides locks set by the same process using a different
+** file descriptor.  Consider this test case:
+**
+**       int fd1 = open("./file1", O_RDWR|O_CREAT, 0644);
+**       int fd2 = open("./file2", O_RDWR|O_CREAT, 0644);
+**
+** Suppose ./file1 and ./file2 are really the same file (because
+** one is a hard or symbolic link to the other) then if you set
+** an exclusive lock on fd1, then try to get an exclusive lock
+** on fd2, it works.  I would have expected the second lock to
+** fail since there was already a lock on the file due to fd1.
+** But not so.  Since both locks came from the same process, the
+** second overrides the first, even though they were on different
+** file descriptors opened on different file names.
+**
+** This means that we cannot use POSIX locks to synchronize file access
+** among competing threads of the same process.  POSIX locks will work fine
+** to synchronize access for threads in separate processes, but not
+** threads within the same process.
+**
+** To work around the problem, SQLite has to manage file locks internally
+** on its own.  Whenever a new database is opened, we have to find the
+** specific inode of the database file (the inode is determined by the
+** st_dev and st_ino fields of the stat structure that fstat() fills in)
+** and check for locks already existing on that inode.  When locks are
+** created or removed, we have to look at our own internal record of the
+** locks to see if another thread has previously set a lock on that same
+** inode.
+**
+** (Aside: The use of inode numbers as unique IDs does not work on VxWorks.
+** For VxWorks, we have to use the alternative unique ID system based on
+** canonical filename and implemented in the previous division.)
+**
+** The sqlite3_file structure for POSIX is no longer just an integer file
+** descriptor.  It is now a structure that holds the integer file
+** descriptor and a pointer to a structure that describes the internal
+** locks on the corresponding inode.  There is one locking structure
+** per inode, so if the same inode is opened twice, both unixFile structures
+** point to the same locking structure.  The locking structure keeps
+** a reference count (so we will know when to delete it) and a "cnt"
+** field that tells us its internal lock status.  cnt==0 means the
+** file is unlocked.  cnt==-1 means the file has an exclusive lock.
+** cnt>0 means there are cnt shared locks on the file.
+**
+** Any attempt to lock or unlock a file first checks the locking
+** structure.  The fcntl() system call is only invoked to set a
+** POSIX lock if the internal lock structure transitions between
+** a locked and an unlocked state.
+**
+** But wait:  there are yet more problems with POSIX advisory locks.
+**
+** If you close a file descriptor that points to a file that has locks,
+** all locks on that file that are owned by the current process are
+** released.  To work around this problem, each unixInodeInfo object
+** maintains a count of the number of pending locks on the inode.
+** When an attempt is made to close an unixFile, if there are
+** other unixFile open on the same inode that are holding locks, the call
+** to close() the file descriptor is deferred until all of the locks clear.
+** The unixInodeInfo structure keeps a list of file descriptors that need to
+** be closed and that list is walked (and cleared) when the last lock
+** clears.
+**
+** Yet another problem:  LinuxThreads do not play well with posix locks.
+**
+** Many older versions of linux use the LinuxThreads library which is
+** not posix compliant.  Under LinuxThreads, a lock created by thread
+** A cannot be modified or overridden by a different thread B.
+** Only thread A can modify the lock.  Locking behavior is correct
+** if the application uses the newer Native Posix Thread Library (NPTL)
+** on linux - with NPTL a lock created by thread A can override locks
+** in thread B.  But there is no way to know at compile-time which
+** threading library is being used.  So there is no way to know at
+** compile-time whether or not thread A can override locks on thread B.
+** One has to do a run-time check to discover the behavior of the
+** current process.
+**
+** SQLite used to support LinuxThreads.  But support for LinuxThreads
+** was dropped beginning with version 3.7.0.  SQLite will still work with
+** LinuxThreads provided that (1) there is no more than one connection
+** per database file in the same process and (2) database connections
+** do not move across threads.
+*/
+
+/*
+** An instance of the following structure serves as the key used
+** to locate a particular unixInodeInfo object.
+*/
+struct unixFileId {
+  dev_t dev;                  /* Device number */
+#if OS_VXWORKS
+  struct vxworksFileId *pId;  /* Unique file ID for vxworks. */
+#else
+  /* We are told that some versions of Android contain a bug that
+  ** sizes ino_t at only 32-bits instead of 64-bits. (See
+  ** https://android-review.googlesource.com/#/c/115351/3/dist/sqlite3.c)
+  ** To work around this, always allocate 64-bits for the inode number.
+  ** On small machines that only have 32-bit inodes, this wastes 4 bytes,
+  ** but that should not be a big deal. */
+  /* WAS:  ino_t ino;   */
+  u64 ino;                   /* Inode number */
+#endif
+};
+
+/*
+** An instance of the following structure is allocated for each open
+** inode.
+**
+** A single inode can have multiple file descriptors, so each unixFile
+** structure contains a pointer to an instance of this object and this
+** object keeps a count of the number of unixFile pointing to it.
+**
+** Mutex rules:
+**
+**  (1) Only the pLockMutex mutex must be held in order to read or write
+**      any of the locking fields:
+**          nShared, nLock, eFileLock, bProcessLock, pUnused
+**
+**  (2) When nRef>0, then the following fields are unchanging and can
+**      be read (but not written) without holding any mutex:
+**          fileId, pLockMutex
+**
+**  (3) With the exceptions above, all the fields may only be read
+**      or written while holding the global unixBigLock mutex.
+**
+** Deadlock prevention:  The global unixBigLock mutex may not
+** be acquired while holding the pLockMutex mutex.  If both unixBigLock
+** and pLockMutex are needed, then unixBigLock must be acquired first.
+*/
+struct unixInodeInfo {
+  struct unixFileId fileId;       /* The lookup key */
+  sqlite3_mutex *pLockMutex;      /* Hold this mutex for... */
+  int nShared;                      /* Number of SHARED locks held */
+  int nLock;                        /* Number of outstanding file locks */
+  unsigned char eFileLock;          /* One of SHARED_LOCK, RESERVED_LOCK etc. */
+  unsigned char bProcessLock;       /* An exclusive process lock is held */
+  UnixUnusedFd *pUnused;            /* Unused file descriptors to close */
+  int nRef;                       /* Number of pointers to this structure */
+  unixShmNode *pShmNode;          /* Shared memory associated with this inode */
+  unixInodeInfo *pNext;           /* List of all unixInodeInfo objects */
+  unixInodeInfo *pPrev;           /*    .... doubly linked */
+#if SQLITE_ENABLE_LOCKING_STYLE
+  unsigned long long sharedByte;  /* for AFP simulated shared lock */
+#endif
+#if OS_VXWORKS
+  sem_t *pSem;                    /* Named POSIX semaphore */
+  char aSemName[MAX_PATHNAME+2];  /* Name of that semaphore */
+#endif
+};
+
+/*
+** A lists of all unixInodeInfo objects.
+**
+** Must hold unixBigLock in order to read or write this variable.
+*/
+static unixInodeInfo *inodeList = 0;  /* All unixInodeInfo objects */
+
+#ifdef SQLITE_DEBUG
+/*
+** True if the inode mutex (on the unixFile.pFileMutex field) is held, or not.
+** This routine is used only within assert() to help verify correct mutex
+** usage.
+*/
+int unixFileMutexHeld(unixFile *pFile){
+  assert( pFile->pInode );
+  return sqlite3_mutex_held(pFile->pInode->pLockMutex);
+}
+int unixFileMutexNotheld(unixFile *pFile){
+  assert( pFile->pInode );
+  return sqlite3_mutex_notheld(pFile->pInode->pLockMutex);
+}
+#endif
+
+/*
+**
+** This function - unixLogErrorAtLine(), is only ever called via the macro
+** unixLogError().
+**
+** It is invoked after an error occurs in an OS function and errno has been
+** set. It logs a message using sqlite3_log() containing the current value of
+** errno and, if possible, the human-readable equivalent from strerror() or
+** strerror_r().
+**
+** The first argument passed to the macro should be the error code that
+** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN).
+** The two subsequent arguments should be the name of the OS function that
+** failed (e.g. "unlink", "open") and the associated file-system path,
+** if any.
+*/
+#define unixLogError(a,b,c)     unixLogErrorAtLine(a,b,c,__LINE__)
+static int unixLogErrorAtLine(
+  int errcode,                    /* SQLite error code */
+  const char *zFunc,              /* Name of OS function that failed */
+  const char *zPath,              /* File path associated with error */
+  int iLine                       /* Source line number where error occurred */
+){
+  char *zErr;                     /* Message from strerror() or equivalent */
+  int iErrno = errno;             /* Saved syscall error number */
+
+  /* If this is not a threadsafe build (SQLITE_THREADSAFE==0), then use
+  ** the strerror() function to obtain the human-readable error message
+  ** equivalent to errno. Otherwise, use strerror_r().
+  */
+#if SQLITE_THREADSAFE && defined(HAVE_STRERROR_R)
+  char aErr[80];
+  memset(aErr, 0, sizeof(aErr));
+  zErr = aErr;
+
+  /* If STRERROR_R_CHAR_P (set by autoconf scripts) or __USE_GNU is defined,
+  ** assume that the system provides the GNU version of strerror_r() that
+  ** returns a pointer to a buffer containing the error message. That pointer
+  ** may point to aErr[], or it may point to some static storage somewhere.
+  ** Otherwise, assume that the system provides the POSIX version of
+  ** strerror_r(), which always writes an error message into aErr[].
+  **
+  ** If the code incorrectly assumes that it is the POSIX version that is
+  ** available, the error message will often be an empty string. Not a
+  ** huge problem. Incorrectly concluding that the GNU version is available
+  ** could lead to a segfault though.
+  **
+  ** Forum post 3f13857fa4062301 reports that the Android SDK may use
+  ** int-type return, depending on its version.
+  */
+#if (defined(STRERROR_R_CHAR_P) || defined(__USE_GNU)) \
+  && !defined(ANDROID) && !defined(__ANDROID__)
+  zErr =
+# endif
+  strerror_r(iErrno, aErr, sizeof(aErr)-1);
+
+#elif SQLITE_THREADSAFE
+  /* This is a threadsafe build, but strerror_r() is not available. */
+  zErr = "";
+#else
+  /* Non-threadsafe build, use strerror(). */
+  zErr = strerror(iErrno);
+#endif
+
+  if( zPath==0 ) zPath = "";
+  sqlite3_log(errcode,
+      "os_unix.c:%d: (%d) %s(%s) - %s",
+      iLine, iErrno, zFunc, zPath, zErr
+  );
+
+  return errcode;
+}
+
+/*
+** Close a file descriptor.
+**
+** We assume that close() almost always works, since it is only in a
+** very sick application or on a very sick platform that it might fail.
+** If it does fail, simply leak the file descriptor, but do log the
+** error.
+**
+** Note that it is not safe to retry close() after EINTR since the
+** file descriptor might have already been reused by another thread.
+** So we don't even try to recover from an EINTR.  Just log the error
+** and move on.
+*/
+static void robust_close(unixFile *pFile, int h, int lineno){
+  if( osClose(h) ){
+    unixLogErrorAtLine(SQLITE_IOERR_CLOSE, "close",
+                       pFile ? pFile->zPath : 0, lineno);
+  }
+}
+
+/*
+** Set the pFile->lastErrno.  Do this in a subroutine as that provides
+** a convenient place to set a breakpoint.
+*/
+static void storeLastErrno(unixFile *pFile, int error){
+  pFile->lastErrno = error;
+}
+
+/*
+** Close all file descriptors accumulated in the unixInodeInfo->pUnused list.
+*/
+static void closePendingFds(unixFile *pFile){
+  unixInodeInfo *pInode = pFile->pInode;
+  UnixUnusedFd *p;
+  UnixUnusedFd *pNext;
+  assert( unixFileMutexHeld(pFile) );
+  for(p=pInode->pUnused; p; p=pNext){
+    pNext = p->pNext;
+    robust_close(pFile, p->fd, __LINE__);
+    sqlite3_free(p);
+  }
+  pInode->pUnused = 0;
+}
+
+/*
+** Release a unixInodeInfo structure previously allocated by findInodeInfo().
+**
+** The global mutex must be held when this routine is called, but the mutex
+** on the inode being deleted must NOT be held.
+*/
+static void releaseInodeInfo(unixFile *pFile){
+  unixInodeInfo *pInode = pFile->pInode;
+  assert( unixMutexHeld() );
+  assert( unixFileMutexNotheld(pFile) );
+  if( ALWAYS(pInode) ){
+    pInode->nRef--;
+    if( pInode->nRef==0 ){
+      assert( pInode->pShmNode==0 );
+      sqlite3_mutex_enter(pInode->pLockMutex);
+      closePendingFds(pFile);
+      sqlite3_mutex_leave(pInode->pLockMutex);
+      if( pInode->pPrev ){
+        assert( pInode->pPrev->pNext==pInode );
+        pInode->pPrev->pNext = pInode->pNext;
+      }else{
+        assert( inodeList==pInode );
+        inodeList = pInode->pNext;
+      }
+      if( pInode->pNext ){
+        assert( pInode->pNext->pPrev==pInode );
+        pInode->pNext->pPrev = pInode->pPrev;
+      }
+      sqlite3_mutex_free(pInode->pLockMutex);
+      sqlite3_free(pInode);
+    }
+  }
+}
+
+/*
+** Given a file descriptor, locate the unixInodeInfo object that
+** describes that file descriptor.  Create a new one if necessary.  The
+** return value might be uninitialized if an error occurs.
+**
+** The global mutex must held when calling this routine.
+**
+** Return an appropriate error code.
+*/
+static int findInodeInfo(
+  unixFile *pFile,               /* Unix file with file desc used in the key */
+  unixInodeInfo **ppInode        /* Return the unixInodeInfo object here */
+){
+  int rc;                        /* System call return code */
+  int fd;                        /* The file descriptor for pFile */
+  struct unixFileId fileId;      /* Lookup key for the unixInodeInfo */
+  struct stat statbuf;           /* Low-level file information */
+  unixInodeInfo *pInode = 0;     /* Candidate unixInodeInfo object */
+
+  assert( unixMutexHeld() );
+
+  /* Get low-level information about the file that we can used to
+  ** create a unique name for the file.
+  */
+  fd = pFile->h;
+  rc = osFstat(fd, &statbuf);
+  if( rc!=0 ){
+    storeLastErrno(pFile, errno);
+#if defined(EOVERFLOW) && defined(SQLITE_DISABLE_LFS)
+    if( pFile->lastErrno==EOVERFLOW ) return SQLITE_NOLFS;
+#endif
+    return SQLITE_IOERR;
+  }
+
+#ifdef __APPLE__
+  /* On OS X on an msdos filesystem, the inode number is reported
+  ** incorrectly for zero-size files.  See ticket #3260.  To work
+  ** around this problem (we consider it a bug in OS X, not SQLite)
+  ** we always increase the file size to 1 by writing a single byte
+  ** prior to accessing the inode number.  The one byte written is
+  ** an ASCII 'S' character which also happens to be the first byte
+  ** in the header of every SQLite database.  In this way, if there
+  ** is a race condition such that another thread has already populated
+  ** the first page of the database, no damage is done.
+  */
+  if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){
+    do{ rc = osWrite(fd, "S", 1); }while( rc<0 && errno==EINTR );
+    if( rc!=1 ){
+      storeLastErrno(pFile, errno);
+      return SQLITE_IOERR;
+    }
+    rc = osFstat(fd, &statbuf);
+    if( rc!=0 ){
+      storeLastErrno(pFile, errno);
+      return SQLITE_IOERR;
+    }
+  }
+#endif
+
+  memset(&fileId, 0, sizeof(fileId));
+  fileId.dev = statbuf.st_dev;
+#if OS_VXWORKS
+  fileId.pId = pFile->pId;
+#else
+  fileId.ino = (u64)statbuf.st_ino;
+#endif
+  assert( unixMutexHeld() );
+  pInode = inodeList;
+  while( pInode && memcmp(&fileId, &pInode->fileId, sizeof(fileId)) ){
+    pInode = pInode->pNext;
+  }
+  if( pInode==0 ){
+    pInode = sqlite3_malloc64( sizeof(*pInode) );
+    if( pInode==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    memset(pInode, 0, sizeof(*pInode));
+    memcpy(&pInode->fileId, &fileId, sizeof(fileId));
+    if( sqlite3GlobalConfig.bCoreMutex ){
+      pInode->pLockMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+      if( pInode->pLockMutex==0 ){
+        sqlite3_free(pInode);
+        return SQLITE_NOMEM_BKPT;
+      }
+    }
+    pInode->nRef = 1;
+    assert( unixMutexHeld() );
+    pInode->pNext = inodeList;
+    pInode->pPrev = 0;
+    if( inodeList ) inodeList->pPrev = pInode;
+    inodeList = pInode;
+  }else{
+    pInode->nRef++;
+  }
+  *ppInode = pInode;
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if pFile has been renamed or unlinked since it was first opened.
+*/
+static int fileHasMoved(unixFile *pFile){
+#if OS_VXWORKS
+  return pFile->pInode!=0 && pFile->pId!=pFile->pInode->fileId.pId;
+#else
+  struct stat buf;
+  return pFile->pInode!=0 &&
+      (osStat(pFile->zPath, &buf)!=0
+         || (u64)buf.st_ino!=pFile->pInode->fileId.ino);
+#endif
+}
+
+
+/*
+** Check a unixFile that is a database.  Verify the following:
+**
+** (1) There is exactly one hard link on the file
+** (2) The file is not a symbolic link
+** (3) The file has not been renamed or unlinked
+**
+** Issue sqlite3_log(SQLITE_WARNING,...) messages if anything is not right.
+*/
+static void verifyDbFile(unixFile *pFile){
+  struct stat buf;
+  int rc;
+
+  /* These verifications occurs for the main database only */
+  if( pFile->ctrlFlags & UNIXFILE_NOLOCK ) return;
+
+  rc = osFstat(pFile->h, &buf);
+  if( rc!=0 ){
+    sqlite3_log(SQLITE_WARNING, "cannot fstat db file %s", pFile->zPath);
+    return;
+  }
+  if( buf.st_nlink==0 ){
+    sqlite3_log(SQLITE_WARNING, "file unlinked while open: %s", pFile->zPath);
+    return;
+  }
+  if( buf.st_nlink>1 ){
+    sqlite3_log(SQLITE_WARNING, "multiple links to file: %s", pFile->zPath);
+    return;
+  }
+  if( fileHasMoved(pFile) ){
+    sqlite3_log(SQLITE_WARNING, "file renamed while open: %s", pFile->zPath);
+    return;
+  }
+}
+
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
+  int rc = SQLITE_OK;
+  int reserved = 0;
+  unixFile *pFile = (unixFile*)id;
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  assert( pFile );
+  assert( pFile->eFileLock<=SHARED_LOCK );
+  sqlite3_mutex_enter(pFile->pInode->pLockMutex);
+
+  /* Check if a thread in this process holds such a lock */
+  if( pFile->pInode->eFileLock>SHARED_LOCK ){
+    reserved = 1;
+  }
+
+  /* Otherwise see if some other process holds it.
+  */
+#ifndef __DJGPP__
+  if( !reserved && !pFile->pInode->bProcessLock ){
+    struct flock lock;
+    lock.l_whence = SEEK_SET;
+    lock.l_start = RESERVED_BYTE;
+    lock.l_len = 1;
+    lock.l_type = F_WRLCK;
+    if( osFcntl(pFile->h, F_GETLK, &lock) ){
+      rc = SQLITE_IOERR_CHECKRESERVEDLOCK;
+      storeLastErrno(pFile, errno);
+    } else if( lock.l_type!=F_UNLCK ){
+      reserved = 1;
+    }
+  }
+#endif
+
+  sqlite3_mutex_leave(pFile->pInode->pLockMutex);
+  OSTRACE(("TEST WR-LOCK %d %d %d (unix)\n", pFile->h, rc, reserved));
+
+  *pResOut = reserved;
+  return rc;
+}
+
+/* Forward declaration*/
+static int unixSleep(sqlite3_vfs*,int);
+
+/*
+** Set a posix-advisory-lock.
+**
+** There are two versions of this routine.  If compiled with
+** SQLITE_ENABLE_SETLK_TIMEOUT then the routine has an extra parameter
+** which is a pointer to a unixFile.  If the unixFile->iBusyTimeout
+** value is set, then it is the number of milliseconds to wait before
+** failing the lock.  The iBusyTimeout value is always reset back to
+** zero on each call.
+**
+** If SQLITE_ENABLE_SETLK_TIMEOUT is not defined, then do a non-blocking
+** attempt to set the lock.
+*/
+#ifndef SQLITE_ENABLE_SETLK_TIMEOUT
+# define osSetPosixAdvisoryLock(h,x,t) osFcntl(h,F_SETLK,x)
+#else
+static int osSetPosixAdvisoryLock(
+  int h,                /* The file descriptor on which to take the lock */
+  struct flock *pLock,  /* The description of the lock */
+  unixFile *pFile       /* Structure holding timeout value */
+){
+  int tm = pFile->iBusyTimeout;
+  int rc = osFcntl(h,F_SETLK,pLock);
+  while( rc<0 && tm>0 ){
+    /* On systems that support some kind of blocking file lock with a timeout,
+    ** make appropriate changes here to invoke that blocking file lock.  On
+    ** generic posix, however, there is no such API.  So we simply try the
+    ** lock once every millisecond until either the timeout expires, or until
+    ** the lock is obtained. */
+    unixSleep(0,1000);
+    rc = osFcntl(h,F_SETLK,pLock);
+    tm--;
+  }
+  return rc;
+}
+#endif /* SQLITE_ENABLE_SETLK_TIMEOUT */
+
+
+/*
+** Attempt to set a system-lock on the file pFile.  The lock is
+** described by pLock.
+**
+** If the pFile was opened read/write from unix-excl, then the only lock
+** ever obtained is an exclusive lock, and it is obtained exactly once
+** the first time any lock is attempted.  All subsequent system locking
+** operations become no-ops.  Locking operations still happen internally,
+** in order to coordinate access between separate database connections
+** within this process, but all of that is handled in memory and the
+** operating system does not participate.
+**
+** This function is a pass-through to fcntl(F_SETLK) if pFile is using
+** any VFS other than "unix-excl" or if pFile is opened on "unix-excl"
+** and is read-only.
+**
+** Zero is returned if the call completes successfully, or -1 if a call
+** to fcntl() fails. In this case, errno is set appropriately (by fcntl()).
+*/
+static int unixFileLock(unixFile *pFile, struct flock *pLock){
+  int rc;
+  unixInodeInfo *pInode = pFile->pInode;
+  assert( pInode!=0 );
+  assert( sqlite3_mutex_held(pInode->pLockMutex) );
+  if( (pFile->ctrlFlags & (UNIXFILE_EXCL|UNIXFILE_RDONLY))==UNIXFILE_EXCL ){
+    if( pInode->bProcessLock==0 ){
+      struct flock lock;
+      /* assert( pInode->nLock==0 ); <-- Not true if unix-excl READONLY used */
+      lock.l_whence = SEEK_SET;
+      lock.l_start = SHARED_FIRST;
+      lock.l_len = SHARED_SIZE;
+      lock.l_type = F_WRLCK;
+      rc = osSetPosixAdvisoryLock(pFile->h, &lock, pFile);
+      if( rc<0 ) return rc;
+      pInode->bProcessLock = 1;
+      pInode->nLock++;
+    }else{
+      rc = 0;
+    }
+  }else{
+    rc = osSetPosixAdvisoryLock(pFile->h, pLock, pFile);
+  }
+  return rc;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int unixLock(sqlite3_file *id, int eFileLock){
+  /* The following describes the implementation of the various locks and
+  ** lock transitions in terms of the POSIX advisory shared and exclusive
+  ** lock primitives (called read-locks and write-locks below, to avoid
+  ** confusion with SQLite lock names). The algorithms are complicated
+  ** slightly in order to be compatible with Windows95 systems simultaneously
+  ** accessing the same database file, in case that is ever required.
+  **
+  ** Symbols defined in os.h identify the 'pending byte' and the 'reserved
+  ** byte', each single bytes at well known offsets, and the 'shared byte
+  ** range', a range of 510 bytes at a well known offset.
+  **
+  ** To obtain a SHARED lock, a read-lock is obtained on the 'pending
+  ** byte'.  If this is successful, 'shared byte range' is read-locked
+  ** and the lock on the 'pending byte' released.  (Legacy note:  When
+  ** SQLite was first developed, Windows95 systems were still very common,
+  ** and Windows95 lacks a shared-lock capability.  So on Windows95, a
+  ** single randomly selected by from the 'shared byte range' is locked.
+  ** Windows95 is now pretty much extinct, but this work-around for the
+  ** lack of shared-locks on Windows95 lives on, for backwards
+  ** compatibility.)
+  **
+  ** A process may only obtain a RESERVED lock after it has a SHARED lock.
+  ** A RESERVED lock is implemented by grabbing a write-lock on the
+  ** 'reserved byte'.
+  **
+  ** An EXCLUSIVE lock may only be requested after either a SHARED or
+  ** RESERVED lock is held. An EXCLUSIVE lock is implemented by obtaining
+  ** a write-lock on the entire 'shared byte range'. Since all other locks
+  ** require a read-lock on one of the bytes within this range, this ensures
+  ** that no other locks are held on the database.
+  **
+  ** If a process that holds a RESERVED lock requests an EXCLUSIVE, then
+  ** a PENDING lock is obtained first. A PENDING lock is implemented by
+  ** obtaining a write-lock on the 'pending byte'. This ensures that no new
+  ** SHARED locks can be obtained, but existing SHARED locks are allowed to
+  ** persist. If the call to this function fails to obtain the EXCLUSIVE
+  ** lock in this case, it holds the PENDING lock instead. The client may
+  ** then re-attempt the EXCLUSIVE lock later on, after existing SHARED
+  ** locks have cleared.
+  */
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode;
+  struct flock lock;
+  int tErrno = 0;
+
+  assert( pFile );
+  OSTRACE(("LOCK    %d %s was %s(%s,%d) pid=%d (unix)\n", pFile->h,
+      azFileLock(eFileLock), azFileLock(pFile->eFileLock),
+      azFileLock(pFile->pInode->eFileLock), pFile->pInode->nShared,
+      osGetpid(0)));
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** unixFile, do nothing. Don't use the end_lock: exit path, as
+  ** unixEnterMutex() hasn't been called yet.
+  */
+  if( pFile->eFileLock>=eFileLock ){
+    OSTRACE(("LOCK    %d %s ok (already held) (unix)\n", pFile->h,
+            azFileLock(eFileLock)));
+    return SQLITE_OK;
+  }
+
+  /* Make sure the locking sequence is correct.
+  **  (1) We never move from unlocked to anything higher than shared lock.
+  **  (2) SQLite never explicitly requests a pending lock.
+  **  (3) A shared lock is always held when a reserve lock is requested.
+  */
+  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
+  assert( eFileLock!=PENDING_LOCK );
+  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );
+
+  /* This mutex is needed because pFile->pInode is shared across threads
+  */
+  pInode = pFile->pInode;
+  sqlite3_mutex_enter(pInode->pLockMutex);
+
+  /* If some thread using this PID has a lock via a different unixFile*
+  ** handle that precludes the requested lock, return BUSY.
+  */
+  if( (pFile->eFileLock!=pInode->eFileLock &&
+          (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK))
+  ){
+    rc = SQLITE_BUSY;
+    goto end_lock;
+  }
+
+  /* If a SHARED lock is requested, and some thread using this PID already
+  ** has a SHARED or RESERVED lock, then increment reference counts and
+  ** return SQLITE_OK.
+  */
+  if( eFileLock==SHARED_LOCK &&
+      (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){
+    assert( eFileLock==SHARED_LOCK );
+    assert( pFile->eFileLock==0 );
+    assert( pInode->nShared>0 );
+    pFile->eFileLock = SHARED_LOCK;
+    pInode->nShared++;
+    pInode->nLock++;
+    goto end_lock;
+  }
+
+
+  /* A PENDING lock is needed before acquiring a SHARED lock and before
+  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
+  ** be released.
+  */
+  lock.l_len = 1L;
+  lock.l_whence = SEEK_SET;
+  if( eFileLock==SHARED_LOCK
+   || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock==RESERVED_LOCK)
+  ){
+    lock.l_type = (eFileLock==SHARED_LOCK?F_RDLCK:F_WRLCK);
+    lock.l_start = PENDING_BYTE;
+    if( unixFileLock(pFile, &lock) ){
+      tErrno = errno;
+      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+      if( rc!=SQLITE_BUSY ){
+        storeLastErrno(pFile, tErrno);
+      }
+      goto end_lock;
+    }else if( eFileLock==EXCLUSIVE_LOCK ){
+      pFile->eFileLock = PENDING_LOCK;
+      pInode->eFileLock = PENDING_LOCK;
+    }
+  }
+
+
+  /* If control gets to this point, then actually go ahead and make
+  ** operating system calls for the specified lock.
+  */
+  if( eFileLock==SHARED_LOCK ){
+    assert( pInode->nShared==0 );
+    assert( pInode->eFileLock==0 );
+    assert( rc==SQLITE_OK );
+
+    /* Now get the read-lock */
+    lock.l_start = SHARED_FIRST;
+    lock.l_len = SHARED_SIZE;
+    if( unixFileLock(pFile, &lock) ){
+      tErrno = errno;
+      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+    }
+
+    /* Drop the temporary PENDING lock */
+    lock.l_start = PENDING_BYTE;
+    lock.l_len = 1L;
+    lock.l_type = F_UNLCK;
+    if( unixFileLock(pFile, &lock) && rc==SQLITE_OK ){
+      /* This could happen with a network mount */
+      tErrno = errno;
+      rc = SQLITE_IOERR_UNLOCK;
+    }
+
+    if( rc ){
+      if( rc!=SQLITE_BUSY ){
+        storeLastErrno(pFile, tErrno);
+      }
+      goto end_lock;
+    }else{
+      pFile->eFileLock = SHARED_LOCK;
+      pInode->nLock++;
+      pInode->nShared = 1;
+    }
+  }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){
+    /* We are trying for an exclusive lock but another thread in this
+    ** same process is still holding a shared lock. */
+    rc = SQLITE_BUSY;
+  }else{
+    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
+    ** assumed that there is a SHARED or greater lock on the file
+    ** already.
+    */
+    assert( 0!=pFile->eFileLock );
+    lock.l_type = F_WRLCK;
+
+    assert( eFileLock==RESERVED_LOCK || eFileLock==EXCLUSIVE_LOCK );
+    if( eFileLock==RESERVED_LOCK ){
+      lock.l_start = RESERVED_BYTE;
+      lock.l_len = 1L;
+    }else{
+      lock.l_start = SHARED_FIRST;
+      lock.l_len = SHARED_SIZE;
+    }
+
+    if( unixFileLock(pFile, &lock) ){
+      tErrno = errno;
+      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+      if( rc!=SQLITE_BUSY ){
+        storeLastErrno(pFile, tErrno);
+      }
+    }
+  }
+
+
+#ifdef SQLITE_DEBUG
+  /* Set up the transaction-counter change checking flags when
+  ** transitioning from a SHARED to a RESERVED lock.  The change
+  ** from SHARED to RESERVED marks the beginning of a normal
+  ** write operation (not a hot journal rollback).
+  */
+  if( rc==SQLITE_OK
+   && pFile->eFileLock<=SHARED_LOCK
+   && eFileLock==RESERVED_LOCK
+  ){
+    pFile->transCntrChng = 0;
+    pFile->dbUpdate = 0;
+    pFile->inNormalWrite = 1;
+  }
+#endif
+
+  if( rc==SQLITE_OK ){
+    pFile->eFileLock = eFileLock;
+    pInode->eFileLock = eFileLock;
+  }
+
+end_lock:
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  OSTRACE(("LOCK    %d %s %s (unix)\n", pFile->h, azFileLock(eFileLock),
+      rc==SQLITE_OK ? "ok" : "failed"));
+  return rc;
+}
+
+/*
+** Add the file descriptor used by file handle pFile to the corresponding
+** pUnused list.
+*/
+static void setPendingFd(unixFile *pFile){
+  unixInodeInfo *pInode = pFile->pInode;
+  UnixUnusedFd *p = pFile->pPreallocatedUnused;
+  assert( unixFileMutexHeld(pFile) );
+  p->pNext = pInode->pUnused;
+  pInode->pUnused = p;
+  pFile->h = -1;
+  pFile->pPreallocatedUnused = 0;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+**
+** If handleNFSUnlock is true, then on downgrading an EXCLUSIVE_LOCK to SHARED
+** the byte range is divided into 2 parts and the first part is unlocked then
+** set to a read lock, then the other part is simply unlocked.  This works
+** around a bug in BSD NFS lockd (also seen on MacOSX 10.3+) that fails to
+** remove the write lock on a region when a read lock is set.
+*/
+static int posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
+  unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode;
+  struct flock lock;
+  int rc = SQLITE_OK;
+
+  assert( pFile );
+  OSTRACE(("UNLOCK  %d %d was %d(%d,%d) pid=%d (unix)\n", pFile->h, eFileLock,
+      pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared,
+      osGetpid(0)));
+
+  assert( eFileLock<=SHARED_LOCK );
+  if( pFile->eFileLock<=eFileLock ){
+    return SQLITE_OK;
+  }
+  pInode = pFile->pInode;
+  sqlite3_mutex_enter(pInode->pLockMutex);
+  assert( pInode->nShared!=0 );
+  if( pFile->eFileLock>SHARED_LOCK ){
+    assert( pInode->eFileLock==pFile->eFileLock );
+
+#ifdef SQLITE_DEBUG
+    /* When reducing a lock such that other processes can start
+    ** reading the database file again, make sure that the
+    ** transaction counter was updated if any part of the database
+    ** file changed.  If the transaction counter is not updated,
+    ** other connections to the same file might not realize that
+    ** the file has changed and hence might not know to flush their
+    ** cache.  The use of a stale cache can lead to database corruption.
+    */
+    pFile->inNormalWrite = 0;
+#endif
+
+    /* downgrading to a shared lock on NFS involves clearing the write lock
+    ** before establishing the readlock - to avoid a race condition we downgrade
+    ** the lock in 2 blocks, so that part of the range will be covered by a
+    ** write lock until the rest is covered by a read lock:
+    **  1:   [WWWWW]
+    **  2:   [....W]
+    **  3:   [RRRRW]
+    **  4:   [RRRR.]
+    */
+    if( eFileLock==SHARED_LOCK ){
+#if !defined(__APPLE__) || !SQLITE_ENABLE_LOCKING_STYLE
+      (void)handleNFSUnlock;
+      assert( handleNFSUnlock==0 );
+#endif
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+      if( handleNFSUnlock ){
+        int tErrno;               /* Error code from system call errors */
+        off_t divSize = SHARED_SIZE - 1;
+
+        lock.l_type = F_UNLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = divSize;
+        if( unixFileLock(pFile, &lock)==(-1) ){
+          tErrno = errno;
+          rc = SQLITE_IOERR_UNLOCK;
+          storeLastErrno(pFile, tErrno);
+          goto end_unlock;
+        }
+        lock.l_type = F_RDLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = divSize;
+        if( unixFileLock(pFile, &lock)==(-1) ){
+          tErrno = errno;
+          rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
+          if( IS_LOCK_ERROR(rc) ){
+            storeLastErrno(pFile, tErrno);
+          }
+          goto end_unlock;
+        }
+        lock.l_type = F_UNLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST+divSize;
+        lock.l_len = SHARED_SIZE-divSize;
+        if( unixFileLock(pFile, &lock)==(-1) ){
+          tErrno = errno;
+          rc = SQLITE_IOERR_UNLOCK;
+          storeLastErrno(pFile, tErrno);
+          goto end_unlock;
+        }
+      }else
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+      {
+        lock.l_type = F_RDLCK;
+        lock.l_whence = SEEK_SET;
+        lock.l_start = SHARED_FIRST;
+        lock.l_len = SHARED_SIZE;
+        if( unixFileLock(pFile, &lock) ){
+          /* In theory, the call to unixFileLock() cannot fail because another
+          ** process is holding an incompatible lock. If it does, this
+          ** indicates that the other process is not following the locking
+          ** protocol. If this happens, return SQLITE_IOERR_RDLOCK. Returning
+          ** SQLITE_BUSY would confuse the upper layer (in practice it causes
+          ** an assert to fail). */
+          rc = SQLITE_IOERR_RDLOCK;
+          storeLastErrno(pFile, errno);
+          goto end_unlock;
+        }
+      }
+    }
+    lock.l_type = F_UNLCK;
+    lock.l_whence = SEEK_SET;
+    lock.l_start = PENDING_BYTE;
+    lock.l_len = 2L;  assert( PENDING_BYTE+1==RESERVED_BYTE );
+    if( unixFileLock(pFile, &lock)==0 ){
+      pInode->eFileLock = SHARED_LOCK;
+    }else{
+      rc = SQLITE_IOERR_UNLOCK;
+      storeLastErrno(pFile, errno);
+      goto end_unlock;
+    }
+  }
+  if( eFileLock==NO_LOCK ){
+    /* Decrement the shared lock counter.  Release the lock using an
+    ** OS call only when all threads in this same process have released
+    ** the lock.
+    */
+    pInode->nShared--;
+    if( pInode->nShared==0 ){
+      lock.l_type = F_UNLCK;
+      lock.l_whence = SEEK_SET;
+      lock.l_start = lock.l_len = 0L;
+      if( unixFileLock(pFile, &lock)==0 ){
+        pInode->eFileLock = NO_LOCK;
+      }else{
+        rc = SQLITE_IOERR_UNLOCK;
+        storeLastErrno(pFile, errno);
+        pInode->eFileLock = NO_LOCK;
+        pFile->eFileLock = NO_LOCK;
+      }
+    }
+
+    /* Decrement the count of locks against this same file.  When the
+    ** count reaches zero, close any other file descriptors whose close
+    ** was deferred because of outstanding locks.
+    */
+    pInode->nLock--;
+    assert( pInode->nLock>=0 );
+    if( pInode->nLock==0 ) closePendingFds(pFile);
+  }
+
+end_unlock:
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  if( rc==SQLITE_OK ){
+    pFile->eFileLock = eFileLock;
+  }
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int unixUnlock(sqlite3_file *id, int eFileLock){
+#if SQLITE_MAX_MMAP_SIZE>0
+  assert( eFileLock==SHARED_LOCK || ((unixFile *)id)->nFetchOut==0 );
+#endif
+  return posixUnlock(id, eFileLock, 0);
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+static int unixMapfile(unixFile *pFd, i64 nByte);
+static void unixUnmapfile(unixFile *pFd);
+#endif
+
+/*
+** This function performs the parts of the "close file" operation
+** common to all locking schemes. It closes the directory and file
+** handles, if they are valid, and sets all fields of the unixFile
+** structure to 0.
+**
+** It is *not* necessary to hold the mutex when this routine is called,
+** even on VxWorks.  A mutex will be acquired on VxWorks by the
+** vxworksReleaseFileId() routine.
+*/
+static int closeUnixFile(sqlite3_file *id){
+  unixFile *pFile = (unixFile*)id;
+#if SQLITE_MAX_MMAP_SIZE>0
+  unixUnmapfile(pFile);
+#endif
+  if( pFile->h>=0 ){
+    robust_close(pFile, pFile->h, __LINE__);
+    pFile->h = -1;
+  }
+#if OS_VXWORKS
+  if( pFile->pId ){
+    if( pFile->ctrlFlags & UNIXFILE_DELETE ){
+      osUnlink(pFile->pId->zCanonicalName);
+    }
+    vxworksReleaseFileId(pFile->pId);
+    pFile->pId = 0;
+  }
+#endif
+#ifdef SQLITE_UNLINK_AFTER_CLOSE
+  if( pFile->ctrlFlags & UNIXFILE_DELETE ){
+    osUnlink(pFile->zPath);
+    sqlite3_free(*(char**)&pFile->zPath);
+    pFile->zPath = 0;
+  }
+#endif
+  OSTRACE(("CLOSE   %-3d\n", pFile->h));
+  OpenCounter(-1);
+  sqlite3_free(pFile->pPreallocatedUnused);
+  memset(pFile, 0, sizeof(unixFile));
+  return SQLITE_OK;
+}
+
+/*
+** Close a file.
+*/
+static int unixClose(sqlite3_file *id){
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile *)id;
+  unixInodeInfo *pInode = pFile->pInode;
+
+  assert( pInode!=0 );
+  verifyDbFile(pFile);
+  unixUnlock(id, NO_LOCK);
+  assert( unixFileMutexNotheld(pFile) );
+  unixEnterMutex();
+
+  /* unixFile.pInode is always valid here. Otherwise, a different close
+  ** routine (e.g. nolockClose()) would be called instead.
+  */
+  assert( pFile->pInode->nLock>0 || pFile->pInode->bProcessLock==0 );
+  sqlite3_mutex_enter(pInode->pLockMutex);
+  if( pInode->nLock ){
+    /* If there are outstanding locks, do not actually close the file just
+    ** yet because that would clear those locks.  Instead, add the file
+    ** descriptor to pInode->pUnused list.  It will be automatically closed
+    ** when the last lock is cleared.
+    */
+    setPendingFd(pFile);
+  }
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  releaseInodeInfo(pFile);
+  assert( pFile->pShm==0 );
+  rc = closeUnixFile(id);
+  unixLeaveMutex();
+  return rc;
+}
+
+/************** End of the posix advisory lock implementation *****************
+******************************************************************************/
+
+/******************************************************************************
+****************************** No-op Locking **********************************
+**
+** Of the various locking implementations available, this is by far the
+** simplest:  locking is ignored.  No attempt is made to lock the database
+** file for reading or writing.
+**
+** This locking mode is appropriate for use on read-only databases
+** (ex: databases that are burned into CD-ROM, for example.)  It can
+** also be used if the application employs some external mechanism to
+** prevent simultaneous access of the same database by two or more
+** database connections.  But there is a serious risk of database
+** corruption if this locking mode is used in situations where multiple
+** database connections are accessing the same database file at the same
+** time and one or more of those connections are writing.
+*/
+
+static int nolockCheckReservedLock(sqlite3_file *NotUsed, int *pResOut){
+  UNUSED_PARAMETER(NotUsed);
+  *pResOut = 0;
+  return SQLITE_OK;
+}
+static int nolockLock(sqlite3_file *NotUsed, int NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  return SQLITE_OK;
+}
+static int nolockUnlock(sqlite3_file *NotUsed, int NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  return SQLITE_OK;
+}
+
+/*
+** Close the file.
+*/
+static int nolockClose(sqlite3_file *id) {
+  return closeUnixFile(id);
+}
+
+/******************* End of the no-op lock implementation *********************
+******************************************************************************/
+
+/******************************************************************************
+************************* Begin dot-file Locking ******************************
+**
+** The dotfile locking implementation uses the existence of separate lock
+** files (really a directory) to control access to the database.  This works
+** on just about every filesystem imaginable.  But there are serious downsides:
+**
+**    (1)  There is zero concurrency.  A single reader blocks all other
+**         connections from reading or writing the database.
+**
+**    (2)  An application crash or power loss can leave stale lock files
+**         sitting around that need to be cleared manually.
+**
+** Nevertheless, a dotlock is an appropriate locking mode for use if no
+** other locking strategy is available.
+**
+** Dotfile locking works by creating a subdirectory in the same directory as
+** the database and with the same name but with a ".lock" extension added.
+** The existence of a lock directory implies an EXCLUSIVE lock.  All other
+** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
+*/
+
+/*
+** The file suffix added to the data base filename in order to create the
+** lock directory.
+*/
+#define DOTLOCK_SUFFIX ".lock"
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If the caller holds a SHARED
+** or greater lock when it is called, then it is assumed that no other
+** client may hold RESERVED. Or, if the caller holds no lock, then it
+** is assumed another client holds RESERVED if the lock-file exists.
+*/
+static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) {
+  unixFile *pFile = (unixFile*)id;
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  if( pFile->eFileLock>=SHARED_LOCK ){
+    *pResOut = 0;
+  }else{
+    *pResOut = osAccess((const char*)pFile->lockingContext, 0)==0;
+  }
+  OSTRACE(("TEST WR-LOCK %d %d %d (dotlock)\n", pFile->h, 0, *pResOut));
+  return SQLITE_OK;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+**
+** With dotfile locking, we really only support state (4): EXCLUSIVE.
+** But we track the other locking levels internally.
+*/
+static int dotlockLock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  char *zLockFile = (char *)pFile->lockingContext;
+  int rc = SQLITE_OK;
+
+
+  /* If we have any lock, then the lock file already exists.  All we have
+  ** to do is adjust our internal record of the lock level.
+  */
+  if( pFile->eFileLock > NO_LOCK ){
+    pFile->eFileLock = eFileLock;
+    /* Always update the timestamp on the old file */
+#ifdef HAVE_UTIME
+    utime(zLockFile, NULL);
+#else
+    utimes(zLockFile, NULL);
+#endif
+    return SQLITE_OK;
+  }
+
+  /* grab an exclusive lock */
+  rc = osMkdir(zLockFile, 0777);
+  if( rc<0 ){
+    /* failed to open/create the lock directory */
+    int tErrno = errno;
+    if( EEXIST == tErrno ){
+      rc = SQLITE_BUSY;
+    } else {
+      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+      if( rc!=SQLITE_BUSY ){
+        storeLastErrno(pFile, tErrno);
+      }
+    }
+    return rc;
+  }
+
+  /* got it, set the type and return ok */
+  pFile->eFileLock = eFileLock;
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+**
+** When the locking level reaches NO_LOCK, delete the lock file.
+*/
+static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  char *zLockFile = (char *)pFile->lockingContext;
+  int rc;
+
+  assert( pFile );
+  OSTRACE(("UNLOCK  %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock,
+           pFile->eFileLock, osGetpid(0)));
+  assert( eFileLock<=SHARED_LOCK );
+
+  /* no-op if possible */
+  if( pFile->eFileLock==eFileLock ){
+    return SQLITE_OK;
+  }
+
+  /* To downgrade to shared, simply update our internal notion of the
+  ** lock state.  No need to mess with the file on disk.
+  */
+  if( eFileLock==SHARED_LOCK ){
+    pFile->eFileLock = SHARED_LOCK;
+    return SQLITE_OK;
+  }
+
+  /* To fully unlock the database, delete the lock file */
+  assert( eFileLock==NO_LOCK );
+  rc = osRmdir(zLockFile);
+  if( rc<0 ){
+    int tErrno = errno;
+    if( tErrno==ENOENT ){
+      rc = SQLITE_OK;
+    }else{
+      rc = SQLITE_IOERR_UNLOCK;
+      storeLastErrno(pFile, tErrno);
+    }
+    return rc;
+  }
+  pFile->eFileLock = NO_LOCK;
+  return SQLITE_OK;
+}
+
+/*
+** Close a file.  Make sure the lock has been released before closing.
+*/
+static int dotlockClose(sqlite3_file *id) {
+  unixFile *pFile = (unixFile*)id;
+  assert( id!=0 );
+  dotlockUnlock(id, NO_LOCK);
+  sqlite3_free(pFile->lockingContext);
+  return closeUnixFile(id);
+}
+/****************** End of the dot-file lock implementation *******************
+******************************************************************************/
+
+/******************************************************************************
+************************** Begin flock Locking ********************************
+**
+** Use the flock() system call to do file locking.
+**
+** flock() locking is like dot-file locking in that the various
+** fine-grain locking levels supported by SQLite are collapsed into
+** a single exclusive lock.  In other words, SHARED, RESERVED, and
+** PENDING locks are the same thing as an EXCLUSIVE lock.  SQLite
+** still works when you do this, but concurrency is reduced since
+** only a single process can be reading the database at a time.
+**
+** Omit this section if SQLITE_ENABLE_LOCKING_STYLE is turned off
+*/
+#if SQLITE_ENABLE_LOCKING_STYLE
+
+/*
+** Retry flock() calls that fail with EINTR
+*/
+#ifdef EINTR
+static int robust_flock(int fd, int op){
+  int rc;
+  do{ rc = flock(fd,op); }while( rc<0 && errno==EINTR );
+  return rc;
+}
+#else
+# define robust_flock(a,b) flock(a,b)
+#endif
+
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){
+#ifdef SQLITE_DEBUG
+  unixFile *pFile = (unixFile*)id;
+#else
+  UNUSED_PARAMETER(id);
+#endif
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  assert( pFile );
+  assert( pFile->eFileLock<=SHARED_LOCK );
+
+  /* The flock VFS only ever takes exclusive locks (see function flockLock).
+  ** Therefore, if this connection is holding any lock at all, no other
+  ** connection may be holding a RESERVED lock. So set *pResOut to 0
+  ** in this case.
+  **
+  ** Or, this connection may be holding no lock. In that case, set *pResOut to
+  ** 0 as well. The caller will then attempt to take an EXCLUSIVE lock on the
+  ** db in order to roll the hot journal back. If there is another connection
+  ** holding a lock, that attempt will fail and an SQLITE_BUSY returned to
+  ** the user. With other VFS, we try to avoid this, in order to allow a reader
+  ** to proceed while a writer is preparing its transaction. But that won't
+  ** work with the flock VFS - as it always takes EXCLUSIVE locks - so it is
+  ** not a problem in this case.  */
+  *pResOut = 0;
+
+  return SQLITE_OK;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** flock() only really support EXCLUSIVE locks.  We track intermediate
+** lock states in the sqlite3_file structure, but all locks SHARED or
+** above are really EXCLUSIVE locks and exclude all other processes from
+** access the file.
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int flockLock(sqlite3_file *id, int eFileLock) {
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+
+  assert( pFile );
+
+  /* if we already have a lock, it is exclusive.
+  ** Just adjust level and punt on outta here. */
+  if (pFile->eFileLock > NO_LOCK) {
+    pFile->eFileLock = eFileLock;
+    return SQLITE_OK;
+  }
+
+  /* grab an exclusive lock */
+
+  if (robust_flock(pFile->h, LOCK_EX | LOCK_NB)) {
+    int tErrno = errno;
+    /* didn't get, must be busy */
+    rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
+    if( IS_LOCK_ERROR(rc) ){
+      storeLastErrno(pFile, tErrno);
+    }
+  } else {
+    /* got it, set the type and return ok */
+    pFile->eFileLock = eFileLock;
+  }
+  OSTRACE(("LOCK    %d %s %s (flock)\n", pFile->h, azFileLock(eFileLock),
+           rc==SQLITE_OK ? "ok" : "failed"));
+#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
+  if( (rc & 0xff) == SQLITE_IOERR ){
+    rc = SQLITE_BUSY;
+  }
+#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
+  return rc;
+}
+
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int flockUnlock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+
+  assert( pFile );
+  OSTRACE(("UNLOCK  %d %d was %d pid=%d (flock)\n", pFile->h, eFileLock,
+           pFile->eFileLock, osGetpid(0)));
+  assert( eFileLock<=SHARED_LOCK );
+
+  /* no-op if possible */
+  if( pFile->eFileLock==eFileLock ){
+    return SQLITE_OK;
+  }
+
+  /* shared can just be set because we always have an exclusive */
+  if (eFileLock==SHARED_LOCK) {
+    pFile->eFileLock = eFileLock;
+    return SQLITE_OK;
+  }
+
+  /* no, really, unlock. */
+  if( robust_flock(pFile->h, LOCK_UN) ){
+#ifdef SQLITE_IGNORE_FLOCK_LOCK_ERRORS
+    return SQLITE_OK;
+#endif /* SQLITE_IGNORE_FLOCK_LOCK_ERRORS */
+    return SQLITE_IOERR_UNLOCK;
+  }else{
+    pFile->eFileLock = NO_LOCK;
+    return SQLITE_OK;
+  }
+}
+
+/*
+** Close a file.
+*/
+static int flockClose(sqlite3_file *id) {
+  assert( id!=0 );
+  flockUnlock(id, NO_LOCK);
+  return closeUnixFile(id);
+}
+
+#endif /* SQLITE_ENABLE_LOCKING_STYLE && !OS_VXWORK */
+
+/******************* End of the flock lock implementation *********************
+******************************************************************************/
+
+/******************************************************************************
+************************ Begin Named Semaphore Locking ************************
+**
+** Named semaphore locking is only supported on VxWorks.
+**
+** Semaphore locking is like dot-lock and flock in that it really only
+** supports EXCLUSIVE locking.  Only a single process can read or write
+** the database file at a time.  This reduces potential concurrency, but
+** makes the lock implementation much easier.
+*/
+#if OS_VXWORKS
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int semXCheckReservedLock(sqlite3_file *id, int *pResOut) {
+  int rc = SQLITE_OK;
+  int reserved = 0;
+  unixFile *pFile = (unixFile*)id;
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  assert( pFile );
+
+  /* Check if a thread in this process holds such a lock */
+  if( pFile->eFileLock>SHARED_LOCK ){
+    reserved = 1;
+  }
+
+  /* Otherwise see if some other process holds it. */
+  if( !reserved ){
+    sem_t *pSem = pFile->pInode->pSem;
+
+    if( sem_trywait(pSem)==-1 ){
+      int tErrno = errno;
+      if( EAGAIN != tErrno ){
+        rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK);
+        storeLastErrno(pFile, tErrno);
+      } else {
+        /* someone else has the lock when we are in NO_LOCK */
+        reserved = (pFile->eFileLock < SHARED_LOCK);
+      }
+    }else{
+      /* we could have it if we want it */
+      sem_post(pSem);
+    }
+  }
+  OSTRACE(("TEST WR-LOCK %d %d %d (sem)\n", pFile->h, rc, reserved));
+
+  *pResOut = reserved;
+  return rc;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** Semaphore locks only really support EXCLUSIVE locks.  We track intermediate
+** lock states in the sqlite3_file structure, but all locks SHARED or
+** above are really EXCLUSIVE locks and exclude all other processes from
+** access the file.
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int semXLock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  sem_t *pSem = pFile->pInode->pSem;
+  int rc = SQLITE_OK;
+
+  /* if we already have a lock, it is exclusive.
+  ** Just adjust level and punt on outta here. */
+  if (pFile->eFileLock > NO_LOCK) {
+    pFile->eFileLock = eFileLock;
+    rc = SQLITE_OK;
+    goto sem_end_lock;
+  }
+
+  /* lock semaphore now but bail out when already locked. */
+  if( sem_trywait(pSem)==-1 ){
+    rc = SQLITE_BUSY;
+    goto sem_end_lock;
+  }
+
+  /* got it, set the type and return ok */
+  pFile->eFileLock = eFileLock;
+
+ sem_end_lock:
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int semXUnlock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  sem_t *pSem = pFile->pInode->pSem;
+
+  assert( pFile );
+  assert( pSem );
+  OSTRACE(("UNLOCK  %d %d was %d pid=%d (sem)\n", pFile->h, eFileLock,
+           pFile->eFileLock, osGetpid(0)));
+  assert( eFileLock<=SHARED_LOCK );
+
+  /* no-op if possible */
+  if( pFile->eFileLock==eFileLock ){
+    return SQLITE_OK;
+  }
+
+  /* shared can just be set because we always have an exclusive */
+  if (eFileLock==SHARED_LOCK) {
+    pFile->eFileLock = eFileLock;
+    return SQLITE_OK;
+  }
+
+  /* no, really unlock. */
+  if ( sem_post(pSem)==-1 ) {
+    int rc, tErrno = errno;
+    rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
+    if( IS_LOCK_ERROR(rc) ){
+      storeLastErrno(pFile, tErrno);
+    }
+    return rc;
+  }
+  pFile->eFileLock = NO_LOCK;
+  return SQLITE_OK;
+}
+
+/*
+ ** Close a file.
+ */
+static int semXClose(sqlite3_file *id) {
+  if( id ){
+    unixFile *pFile = (unixFile*)id;
+    semXUnlock(id, NO_LOCK);
+    assert( pFile );
+    assert( unixFileMutexNotheld(pFile) );
+    unixEnterMutex();
+    releaseInodeInfo(pFile);
+    unixLeaveMutex();
+    closeUnixFile(id);
+  }
+  return SQLITE_OK;
+}
+
+#endif /* OS_VXWORKS */
+/*
+** Named semaphore locking is only available on VxWorks.
+**
+*************** End of the named semaphore lock implementation ****************
+******************************************************************************/
+
+
+/******************************************************************************
+*************************** Begin AFP Locking *********************************
+**
+** AFP is the Apple Filing Protocol.  AFP is a network filesystem found
+** on Apple Macintosh computers - both OS9 and OSX.
+**
+** Third-party implementations of AFP are available.  But this code here
+** only works on OSX.
+*/
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+/*
+** The afpLockingContext structure contains all afp lock specific state
+*/
+typedef struct afpLockingContext afpLockingContext;
+struct afpLockingContext {
+  int reserved;
+  const char *dbPath;             /* Name of the open file */
+};
+
+struct ByteRangeLockPB2
+{
+  unsigned long long offset;        /* offset to first byte to lock */
+  unsigned long long length;        /* nbr of bytes to lock */
+  unsigned long long retRangeStart; /* nbr of 1st byte locked if successful */
+  unsigned char unLockFlag;         /* 1 = unlock, 0 = lock */
+  unsigned char startEndFlag;       /* 1=rel to end of fork, 0=rel to start */
+  int fd;                           /* file desc to assoc this lock with */
+};
+
+#define afpfsByteRangeLock2FSCTL        _IOWR('z', 23, struct ByteRangeLockPB2)
+
+/*
+** This is a utility for setting or clearing a bit-range lock on an
+** AFP filesystem.
+**
+** Return SQLITE_OK on success, SQLITE_BUSY on failure.
+*/
+static int afpSetLock(
+  const char *path,              /* Name of the file to be locked or unlocked */
+  unixFile *pFile,               /* Open file descriptor on path */
+  unsigned long long offset,     /* First byte to be locked */
+  unsigned long long length,     /* Number of bytes to lock */
+  int setLockFlag                /* True to set lock.  False to clear lock */
+){
+  struct ByteRangeLockPB2 pb;
+  int err;
+
+  pb.unLockFlag = setLockFlag ? 0 : 1;
+  pb.startEndFlag = 0;
+  pb.offset = offset;
+  pb.length = length;
+  pb.fd = pFile->h;
+
+  OSTRACE(("AFPSETLOCK [%s] for %d%s in range %llx:%llx\n",
+    (setLockFlag?"ON":"OFF"), pFile->h, (pb.fd==-1?"[testval-1]":""),
+    offset, length));
+  err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0);
+  if ( err==-1 ) {
+    int rc;
+    int tErrno = errno;
+    OSTRACE(("AFPSETLOCK failed to fsctl() '%s' %d %s\n",
+             path, tErrno, strerror(tErrno)));
+#ifdef SQLITE_IGNORE_AFP_LOCK_ERRORS
+    rc = SQLITE_BUSY;
+#else
+    rc = sqliteErrorFromPosixError(tErrno,
+                    setLockFlag ? SQLITE_IOERR_LOCK : SQLITE_IOERR_UNLOCK);
+#endif /* SQLITE_IGNORE_AFP_LOCK_ERRORS */
+    if( IS_LOCK_ERROR(rc) ){
+      storeLastErrno(pFile, tErrno);
+    }
+    return rc;
+  } else {
+    return SQLITE_OK;
+  }
+}
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int afpCheckReservedLock(sqlite3_file *id, int *pResOut){
+  int rc = SQLITE_OK;
+  int reserved = 0;
+  unixFile *pFile = (unixFile*)id;
+  afpLockingContext *context;
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+
+  assert( pFile );
+  context = (afpLockingContext *) pFile->lockingContext;
+  if( context->reserved ){
+    *pResOut = 1;
+    return SQLITE_OK;
+  }
+  sqlite3_mutex_enter(pFile->pInode->pLockMutex);
+  /* Check if a thread in this process holds such a lock */
+  if( pFile->pInode->eFileLock>SHARED_LOCK ){
+    reserved = 1;
+  }
+
+  /* Otherwise see if some other process holds it.
+   */
+  if( !reserved ){
+    /* lock the RESERVED byte */
+    int lrc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1);
+    if( SQLITE_OK==lrc ){
+      /* if we succeeded in taking the reserved lock, unlock it to restore
+      ** the original state */
+      lrc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0);
+    } else {
+      /* if we failed to get the lock then someone else must have it */
+      reserved = 1;
+    }
+    if( IS_LOCK_ERROR(lrc) ){
+      rc=lrc;
+    }
+  }
+
+  sqlite3_mutex_leave(pFile->pInode->pLockMutex);
+  OSTRACE(("TEST WR-LOCK %d %d %d (afp)\n", pFile->h, rc, reserved));
+
+  *pResOut = reserved;
+  return rc;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int afpLock(sqlite3_file *id, int eFileLock){
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode = pFile->pInode;
+  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+
+  assert( pFile );
+  OSTRACE(("LOCK    %d %s was %s(%s,%d) pid=%d (afp)\n", pFile->h,
+           azFileLock(eFileLock), azFileLock(pFile->eFileLock),
+           azFileLock(pInode->eFileLock), pInode->nShared , osGetpid(0)));
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** unixFile, do nothing. Don't use the afp_end_lock: exit path, as
+  ** unixEnterMutex() hasn't been called yet.
+  */
+  if( pFile->eFileLock>=eFileLock ){
+    OSTRACE(("LOCK    %d %s ok (already held) (afp)\n", pFile->h,
+           azFileLock(eFileLock)));
+    return SQLITE_OK;
+  }
+
+  /* Make sure the locking sequence is correct
+  **  (1) We never move from unlocked to anything higher than shared lock.
+  **  (2) SQLite never explicitly requests a pending lock.
+  **  (3) A shared lock is always held when a reserve lock is requested.
+  */
+  assert( pFile->eFileLock!=NO_LOCK || eFileLock==SHARED_LOCK );
+  assert( eFileLock!=PENDING_LOCK );
+  assert( eFileLock!=RESERVED_LOCK || pFile->eFileLock==SHARED_LOCK );
+
+  /* This mutex is needed because pFile->pInode is shared across threads
+  */
+  pInode = pFile->pInode;
+  sqlite3_mutex_enter(pInode->pLockMutex);
+
+  /* If some thread using this PID has a lock via a different unixFile*
+  ** handle that precludes the requested lock, return BUSY.
+  */
+  if( (pFile->eFileLock!=pInode->eFileLock &&
+       (pInode->eFileLock>=PENDING_LOCK || eFileLock>SHARED_LOCK))
+     ){
+    rc = SQLITE_BUSY;
+    goto afp_end_lock;
+  }
+
+  /* If a SHARED lock is requested, and some thread using this PID already
+  ** has a SHARED or RESERVED lock, then increment reference counts and
+  ** return SQLITE_OK.
+  */
+  if( eFileLock==SHARED_LOCK &&
+     (pInode->eFileLock==SHARED_LOCK || pInode->eFileLock==RESERVED_LOCK) ){
+    assert( eFileLock==SHARED_LOCK );
+    assert( pFile->eFileLock==0 );
+    assert( pInode->nShared>0 );
+    pFile->eFileLock = SHARED_LOCK;
+    pInode->nShared++;
+    pInode->nLock++;
+    goto afp_end_lock;
+  }
+
+  /* A PENDING lock is needed before acquiring a SHARED lock and before
+  ** acquiring an EXCLUSIVE lock.  For the SHARED lock, the PENDING will
+  ** be released.
+  */
+  if( eFileLock==SHARED_LOCK
+      || (eFileLock==EXCLUSIVE_LOCK && pFile->eFileLock<PENDING_LOCK)
+  ){
+    int failed;
+    failed = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 1);
+    if (failed) {
+      rc = failed;
+      goto afp_end_lock;
+    }
+  }
+
+  /* If control gets to this point, then actually go ahead and make
+  ** operating system calls for the specified lock.
+  */
+  if( eFileLock==SHARED_LOCK ){
+    int lrc1, lrc2, lrc1Errno = 0;
+    long lk, mask;
+
+    assert( pInode->nShared==0 );
+    assert( pInode->eFileLock==0 );
+
+    mask = (sizeof(long)==8) ? LARGEST_INT64 : 0x7fffffff;
+    /* Now get the read-lock SHARED_LOCK */
+    /* note that the quality of the randomness doesn't matter that much */
+    lk = random();
+    pInode->sharedByte = (lk & mask)%(SHARED_SIZE - 1);
+    lrc1 = afpSetLock(context->dbPath, pFile,
+          SHARED_FIRST+pInode->sharedByte, 1, 1);
+    if( IS_LOCK_ERROR(lrc1) ){
+      lrc1Errno = pFile->lastErrno;
+    }
+    /* Drop the temporary PENDING lock */
+    lrc2 = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
+
+    if( IS_LOCK_ERROR(lrc1) ) {
+      storeLastErrno(pFile, lrc1Errno);
+      rc = lrc1;
+      goto afp_end_lock;
+    } else if( IS_LOCK_ERROR(lrc2) ){
+      rc = lrc2;
+      goto afp_end_lock;
+    } else if( lrc1 != SQLITE_OK ) {
+      rc = lrc1;
+    } else {
+      pFile->eFileLock = SHARED_LOCK;
+      pInode->nLock++;
+      pInode->nShared = 1;
+    }
+  }else if( eFileLock==EXCLUSIVE_LOCK && pInode->nShared>1 ){
+    /* We are trying for an exclusive lock but another thread in this
+     ** same process is still holding a shared lock. */
+    rc = SQLITE_BUSY;
+  }else{
+    /* The request was for a RESERVED or EXCLUSIVE lock.  It is
+    ** assumed that there is a SHARED or greater lock on the file
+    ** already.
+    */
+    int failed = 0;
+    assert( 0!=pFile->eFileLock );
+    if (eFileLock >= RESERVED_LOCK && pFile->eFileLock < RESERVED_LOCK) {
+        /* Acquire a RESERVED lock */
+        failed = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1);
+      if( !failed ){
+        context->reserved = 1;
+      }
+    }
+    if (!failed && eFileLock == EXCLUSIVE_LOCK) {
+      /* Acquire an EXCLUSIVE lock */
+
+      /* Remove the shared lock before trying the range.  we'll need to
+      ** reestablish the shared lock if we can't get the  afpUnlock
+      */
+      if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST +
+                         pInode->sharedByte, 1, 0)) ){
+        int failed2 = SQLITE_OK;
+        /* now attempt to get the exclusive lock range */
+        failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST,
+                               SHARED_SIZE, 1);
+        if( failed && (failed2 = afpSetLock(context->dbPath, pFile,
+                       SHARED_FIRST + pInode->sharedByte, 1, 1)) ){
+          /* Can't reestablish the shared lock.  Sqlite can't deal, this is
+          ** a critical I/O error
+          */
+          rc = ((failed & 0xff) == SQLITE_IOERR) ? failed2 :
+               SQLITE_IOERR_LOCK;
+          goto afp_end_lock;
+        }
+      }else{
+        rc = failed;
+      }
+    }
+    if( failed ){
+      rc = failed;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    pFile->eFileLock = eFileLock;
+    pInode->eFileLock = eFileLock;
+  }else if( eFileLock==EXCLUSIVE_LOCK ){
+    pFile->eFileLock = PENDING_LOCK;
+    pInode->eFileLock = PENDING_LOCK;
+  }
+
+afp_end_lock:
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  OSTRACE(("LOCK    %d %s %s (afp)\n", pFile->h, azFileLock(eFileLock),
+         rc==SQLITE_OK ? "ok" : "failed"));
+  return rc;
+}
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int afpUnlock(sqlite3_file *id, int eFileLock) {
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  unixInodeInfo *pInode;
+  afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+  int skipShared = 0;
+
+  assert( pFile );
+  OSTRACE(("UNLOCK  %d %d was %d(%d,%d) pid=%d (afp)\n", pFile->h, eFileLock,
+           pFile->eFileLock, pFile->pInode->eFileLock, pFile->pInode->nShared,
+           osGetpid(0)));
+
+  assert( eFileLock<=SHARED_LOCK );
+  if( pFile->eFileLock<=eFileLock ){
+    return SQLITE_OK;
+  }
+  pInode = pFile->pInode;
+  sqlite3_mutex_enter(pInode->pLockMutex);
+  assert( pInode->nShared!=0 );
+  if( pFile->eFileLock>SHARED_LOCK ){
+    assert( pInode->eFileLock==pFile->eFileLock );
+
+#ifdef SQLITE_DEBUG
+    /* When reducing a lock such that other processes can start
+    ** reading the database file again, make sure that the
+    ** transaction counter was updated if any part of the database
+    ** file changed.  If the transaction counter is not updated,
+    ** other connections to the same file might not realize that
+    ** the file has changed and hence might not know to flush their
+    ** cache.  The use of a stale cache can lead to database corruption.
+    */
+    assert( pFile->inNormalWrite==0
+           || pFile->dbUpdate==0
+           || pFile->transCntrChng==1 );
+    pFile->inNormalWrite = 0;
+#endif
+
+    if( pFile->eFileLock==EXCLUSIVE_LOCK ){
+      rc = afpSetLock(context->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0);
+      if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1) ){
+        /* only re-establish the shared lock if necessary */
+        int sharedLockByte = SHARED_FIRST+pInode->sharedByte;
+        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 1);
+      } else {
+        skipShared = 1;
+      }
+    }
+    if( rc==SQLITE_OK && pFile->eFileLock>=PENDING_LOCK ){
+      rc = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
+    }
+    if( rc==SQLITE_OK && pFile->eFileLock>=RESERVED_LOCK && context->reserved ){
+      rc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0);
+      if( !rc ){
+        context->reserved = 0;
+      }
+    }
+    if( rc==SQLITE_OK && (eFileLock==SHARED_LOCK || pInode->nShared>1)){
+      pInode->eFileLock = SHARED_LOCK;
+    }
+  }
+  if( rc==SQLITE_OK && eFileLock==NO_LOCK ){
+
+    /* Decrement the shared lock counter.  Release the lock using an
+    ** OS call only when all threads in this same process have released
+    ** the lock.
+    */
+    unsigned long long sharedLockByte = SHARED_FIRST+pInode->sharedByte;
+    pInode->nShared--;
+    if( pInode->nShared==0 ){
+      if( !skipShared ){
+        rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 0);
+      }
+      if( !rc ){
+        pInode->eFileLock = NO_LOCK;
+        pFile->eFileLock = NO_LOCK;
+      }
+    }
+    if( rc==SQLITE_OK ){
+      pInode->nLock--;
+      assert( pInode->nLock>=0 );
+      if( pInode->nLock==0 ) closePendingFds(pFile);
+    }
+  }
+
+  sqlite3_mutex_leave(pInode->pLockMutex);
+  if( rc==SQLITE_OK ){
+    pFile->eFileLock = eFileLock;
+  }
+  return rc;
+}
+
+/*
+** Close a file & cleanup AFP specific locking context
+*/
+static int afpClose(sqlite3_file *id) {
+  int rc = SQLITE_OK;
+  unixFile *pFile = (unixFile*)id;
+  assert( id!=0 );
+  afpUnlock(id, NO_LOCK);
+  assert( unixFileMutexNotheld(pFile) );
+  unixEnterMutex();
+  if( pFile->pInode ){
+    unixInodeInfo *pInode = pFile->pInode;
+    sqlite3_mutex_enter(pInode->pLockMutex);
+    if( pInode->nLock ){
+      /* If there are outstanding locks, do not actually close the file just
+      ** yet because that would clear those locks.  Instead, add the file
+      ** descriptor to pInode->aPending.  It will be automatically closed when
+      ** the last lock is cleared.
+      */
+      setPendingFd(pFile);
+    }
+    sqlite3_mutex_leave(pInode->pLockMutex);
+  }
+  releaseInodeInfo(pFile);
+  sqlite3_free(pFile->lockingContext);
+  rc = closeUnixFile(id);
+  unixLeaveMutex();
+  return rc;
+}
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+/*
+** The code above is the AFP lock implementation.  The code is specific
+** to MacOSX and does not work on other unix platforms.  No alternative
+** is available.  If you don't compile for a mac, then the "unix-afp"
+** VFS is not available.
+**
+********************* End of the AFP lock implementation **********************
+******************************************************************************/
+
+/******************************************************************************
+*************************** Begin NFS Locking ********************************/
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+/*
+ ** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+ ** must be either NO_LOCK or SHARED_LOCK.
+ **
+ ** If the locking level of the file descriptor is already at or below
+ ** the requested locking level, this routine is a no-op.
+ */
+static int nfsUnlock(sqlite3_file *id, int eFileLock){
+  return posixUnlock(id, eFileLock, 1);
+}
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+/*
+** The code above is the NFS lock implementation.  The code is specific
+** to MacOSX and does not work on other unix platforms.  No alternative
+** is available.
+**
+********************* End of the NFS lock implementation **********************
+******************************************************************************/
+
+/******************************************************************************
+**************** Non-locking sqlite3_file methods *****************************
+**
+** The next division contains implementations for all methods of the
+** sqlite3_file object other than the locking methods.  The locking
+** methods were defined in divisions above (one locking method per
+** division).  Those methods that are common to all locking modes
+** are gather together into this division.
+*/
+
+/*
+** Seek to the offset passed as the second argument, then read cnt
+** bytes into pBuf. Return the number of bytes actually read.
+**
+** To avoid stomping the errno value on a failed read the lastErrno value
+** is set before returning.
+*/
+static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
+  int got;
+  int prior = 0;
+#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
+  i64 newOffset;
+#endif
+  TIMER_START;
+  assert( cnt==(cnt&0x1ffff) );
+  assert( id->h>2 );
+  do{
+#if defined(USE_PREAD)
+    got = osPread(id->h, pBuf, cnt, offset);
+    SimulateIOError( got = -1 );
+#elif defined(USE_PREAD64)
+    got = osPread64(id->h, pBuf, cnt, offset);
+    SimulateIOError( got = -1 );
+#else
+    newOffset = lseek(id->h, offset, SEEK_SET);
+    SimulateIOError( newOffset = -1 );
+    if( newOffset<0 ){
+      storeLastErrno((unixFile*)id, errno);
+      return -1;
+    }
+    got = osRead(id->h, pBuf, cnt);
+#endif
+    if( got==cnt ) break;
+    if( got<0 ){
+      if( errno==EINTR ){ got = 1; continue; }
+      prior = 0;
+      storeLastErrno((unixFile*)id,  errno);
+      break;
+    }else if( got>0 ){
+      cnt -= got;
+      offset += got;
+      prior += got;
+      pBuf = (void*)(got + (char*)pBuf);
+    }
+  }while( got>0 );
+  TIMER_END;
+  OSTRACE(("READ    %-3d %5d %7lld %llu\n",
+            id->h, got+prior, offset-prior, TIMER_ELAPSED));
+  return got+prior;
+}
+
+/*
+** Read data from a file into a buffer.  Return SQLITE_OK if all
+** bytes were read successfully and SQLITE_IOERR if anything goes
+** wrong.
+*/
+static int unixRead(
+  sqlite3_file *id,
+  void *pBuf,
+  int amt,
+  sqlite3_int64 offset
+){
+  unixFile *pFile = (unixFile *)id;
+  int got;
+  assert( id );
+  assert( offset>=0 );
+  assert( amt>0 );
+
+  /* If this is a database file (not a journal, super-journal or temp
+  ** file), the bytes in the locking range should never be read or written. */
+#if 0
+  assert( pFile->pPreallocatedUnused==0
+       || offset>=PENDING_BYTE+512
+       || offset+amt<=PENDING_BYTE
+  );
+#endif
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  /* Deal with as much of this read request as possible by transferring
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt);
+      return SQLITE_OK;
+    }else{
+      int nCopy = pFile->mmapSize - offset;
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+#endif
+
+  got = seekAndRead(pFile, offset, pBuf, amt);
+  if( got==amt ){
+    return SQLITE_OK;
+  }else if( got<0 ){
+    /* pFile->lastErrno has been set by seekAndRead().
+    ** Usually we return SQLITE_IOERR_READ here, though for some
+    ** kinds of errors we return SQLITE_IOERR_CORRUPTFS.  The
+    ** SQLITE_IOERR_CORRUPTFS will be converted into SQLITE_CORRUPT
+    ** prior to returning to the application by the sqlite3ApiExit()
+    ** routine.
+    */
+    switch( pFile->lastErrno ){
+      case ERANGE:
+      case EIO:
+#ifdef ENXIO
+      case ENXIO:
+#endif
+#ifdef EDEVERR
+      case EDEVERR:
+#endif
+        return SQLITE_IOERR_CORRUPTFS;
+    }
+    return SQLITE_IOERR_READ;
+  }else{
+    storeLastErrno(pFile, 0);   /* not a system error */
+    /* Unread parts of the buffer must be zero-filled */
+    memset(&((char*)pBuf)[got], 0, amt-got);
+    return SQLITE_IOERR_SHORT_READ;
+  }
+}
+
+/*
+** Attempt to seek the file-descriptor passed as the first argument to
+** absolute offset iOff, then attempt to write nBuf bytes of data from
+** pBuf to it. If an error occurs, return -1 and set *piErrno. Otherwise,
+** return the actual number of bytes written (which may be less than
+** nBuf).
+*/
+static int seekAndWriteFd(
+  int fd,                         /* File descriptor to write to */
+  i64 iOff,                       /* File offset to begin writing at */
+  const void *pBuf,               /* Copy data from this buffer to the file */
+  int nBuf,                       /* Size of buffer pBuf in bytes */
+  int *piErrno                    /* OUT: Error number if error occurs */
+){
+  int rc = 0;                     /* Value returned by system call */
+
+  assert( nBuf==(nBuf&0x1ffff) );
+  assert( fd>2 );
+  assert( piErrno!=0 );
+  nBuf &= 0x1ffff;
+  TIMER_START;
+
+#if defined(USE_PREAD)
+  do{ rc = (int)osPwrite(fd, pBuf, nBuf, iOff); }while( rc<0 && errno==EINTR );
+#elif defined(USE_PREAD64)
+  do{ rc = (int)osPwrite64(fd, pBuf, nBuf, iOff);}while( rc<0 && errno==EINTR);
+#else
+  do{
+    i64 iSeek = lseek(fd, iOff, SEEK_SET);
+    SimulateIOError( iSeek = -1 );
+    if( iSeek<0 ){
+      rc = -1;
+      break;
+    }
+    rc = osWrite(fd, pBuf, nBuf);
+  }while( rc<0 && errno==EINTR );
+#endif
+
+  TIMER_END;
+  OSTRACE(("WRITE   %-3d %5d %7lld %llu\n", fd, rc, iOff, TIMER_ELAPSED));
+
+  if( rc<0 ) *piErrno = errno;
+  return rc;
+}
+
+
+/*
+** Seek to the offset in id->offset then read cnt bytes into pBuf.
+** Return the number of bytes actually read.  Update the offset.
+**
+** To avoid stomping the errno value on a failed write the lastErrno value
+** is set before returning.
+*/
+static int seekAndWrite(unixFile *id, i64 offset, const void *pBuf, int cnt){
+  return seekAndWriteFd(id->h, offset, pBuf, cnt, &id->lastErrno);
+}
+
+
+/*
+** Write data from a buffer into a file.  Return SQLITE_OK on success
+** or some other error code on failure.
+*/
+static int unixWrite(
+  sqlite3_file *id,
+  const void *pBuf,
+  int amt,
+  sqlite3_int64 offset
+){
+  unixFile *pFile = (unixFile*)id;
+  int wrote = 0;
+  assert( id );
+  assert( amt>0 );
+
+  /* If this is a database file (not a journal, super-journal or temp
+  ** file), the bytes in the locking range should never be read or written. */
+#if 0
+  assert( pFile->pPreallocatedUnused==0
+       || offset>=PENDING_BYTE+512
+       || offset+amt<=PENDING_BYTE
+  );
+#endif
+
+#ifdef SQLITE_DEBUG
+  /* If we are doing a normal write to a database file (as opposed to
+  ** doing a hot-journal rollback or a write to some file other than a
+  ** normal database file) then record the fact that the database
+  ** has changed.  If the transaction counter is modified, record that
+  ** fact too.
+  */
+  if( pFile->inNormalWrite ){
+    pFile->dbUpdate = 1;  /* The database has been modified */
+    if( offset<=24 && offset+amt>=27 ){
+      int rc;
+      char oldCntr[4];
+      SimulateIOErrorBenign(1);
+      rc = seekAndRead(pFile, 24, oldCntr, 4);
+      SimulateIOErrorBenign(0);
+      if( rc!=4 || memcmp(oldCntr, &((char*)pBuf)[24-offset], 4)!=0 ){
+        pFile->transCntrChng = 1;  /* The transaction counter has changed */
+      }
+    }
+  }
+#endif
+
+#if defined(SQLITE_MMAP_READWRITE) && SQLITE_MAX_MMAP_SIZE>0
+  /* Deal with as much of this write request as possible by transferring
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt);
+      return SQLITE_OK;
+    }else{
+      int nCopy = pFile->mmapSize - offset;
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+#endif
+
+  while( (wrote = seekAndWrite(pFile, offset, pBuf, amt))<amt && wrote>0 ){
+    amt -= wrote;
+    offset += wrote;
+    pBuf = &((char*)pBuf)[wrote];
+  }
+  SimulateIOError(( wrote=(-1), amt=1 ));
+  SimulateDiskfullError(( wrote=0, amt=1 ));
+
+  if( amt>wrote ){
+    if( wrote<0 && pFile->lastErrno!=ENOSPC ){
+      /* lastErrno set by seekAndWrite */
+      return SQLITE_IOERR_WRITE;
+    }else{
+      storeLastErrno(pFile, 0); /* not a system error */
+      return SQLITE_FULL;
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Count the number of fullsyncs and normal syncs.  This is used to test
+** that syncs and fullsyncs are occurring at the right times.
+*/
+SQLITE_API int sqlite3_sync_count = 0;
+SQLITE_API int sqlite3_fullsync_count = 0;
+#endif
+
+/*
+** We do not trust systems to provide a working fdatasync().  Some do.
+** Others do no.  To be safe, we will stick with the (slightly slower)
+** fsync(). If you know that your system does support fdatasync() correctly,
+** then simply compile with -Dfdatasync=fdatasync or -DHAVE_FDATASYNC
+*/
+#if !defined(fdatasync) && !HAVE_FDATASYNC
+# define fdatasync fsync
+#endif
+
+/*
+** Define HAVE_FULLFSYNC to 0 or 1 depending on whether or not
+** the F_FULLFSYNC macro is defined.  F_FULLFSYNC is currently
+** only available on Mac OS X.  But that could change.
+*/
+#ifdef F_FULLFSYNC
+# define HAVE_FULLFSYNC 1
+#else
+# define HAVE_FULLFSYNC 0
+#endif
+
+
+/*
+** The fsync() system call does not work as advertised on many
+** unix systems.  The following procedure is an attempt to make
+** it work better.
+**
+** The SQLITE_NO_SYNC macro disables all fsync()s.  This is useful
+** for testing when we want to run through the test suite quickly.
+** You are strongly advised *not* to deploy with SQLITE_NO_SYNC
+** enabled, however, since with SQLITE_NO_SYNC enabled, an OS crash
+** or power failure will likely corrupt the database file.
+**
+** SQLite sets the dataOnly flag if the size of the file is unchanged.
+** The idea behind dataOnly is that it should only write the file content
+** to disk, not the inode.  We only set dataOnly if the file size is
+** unchanged since the file size is part of the inode.  However,
+** Ted Ts'o tells us that fdatasync() will also write the inode if the
+** file size has changed.  The only real difference between fdatasync()
+** and fsync(), Ted tells us, is that fdatasync() will not flush the
+** inode if the mtime or owner or other inode attributes have changed.
+** We only care about the file size, not the other file attributes, so
+** as far as SQLite is concerned, an fdatasync() is always adequate.
+** So, we always use fdatasync() if it is available, regardless of
+** the value of the dataOnly flag.
+*/
+static int full_fsync(int fd, int fullSync, int dataOnly){
+  int rc;
+
+  /* The following "ifdef/elif/else/" block has the same structure as
+  ** the one below. It is replicated here solely to avoid cluttering
+  ** up the real code with the UNUSED_PARAMETER() macros.
+  */
+#ifdef SQLITE_NO_SYNC
+  UNUSED_PARAMETER(fd);
+  UNUSED_PARAMETER(fullSync);
+  UNUSED_PARAMETER(dataOnly);
+#elif HAVE_FULLFSYNC
+  UNUSED_PARAMETER(dataOnly);
+#else
+  UNUSED_PARAMETER(fullSync);
+  UNUSED_PARAMETER(dataOnly);
+#endif
+
+  /* Record the number of times that we do a normal fsync() and
+  ** FULLSYNC.  This is used during testing to verify that this procedure
+  ** gets called with the correct arguments.
+  */
+#ifdef SQLITE_TEST
+  if( fullSync ) sqlite3_fullsync_count++;
+  sqlite3_sync_count++;
+#endif
+
+  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
+  ** no-op.  But go ahead and call fstat() to validate the file
+  ** descriptor as we need a method to provoke a failure during
+  ** coverage testing.
+  */
+#ifdef SQLITE_NO_SYNC
+  {
+    struct stat buf;
+    rc = osFstat(fd, &buf);
+  }
+#elif HAVE_FULLFSYNC
+  if( fullSync ){
+    rc = osFcntl(fd, F_FULLFSYNC, 0);
+  }else{
+    rc = 1;
+  }
+  /* If the FULLFSYNC failed, fall back to attempting an fsync().
+  ** It shouldn't be possible for fullfsync to fail on the local
+  ** file system (on OSX), so failure indicates that FULLFSYNC
+  ** isn't supported for this file system. So, attempt an fsync
+  ** and (for now) ignore the overhead of a superfluous fcntl call.
+  ** It'd be better to detect fullfsync support once and avoid
+  ** the fcntl call every time sync is called.
+  */
+  if( rc ) rc = fsync(fd);
+
+#elif defined(__APPLE__)
+  /* fdatasync() on HFS+ doesn't yet flush the file size if it changed correctly
+  ** so currently we default to the macro that redefines fdatasync to fsync
+  */
+  rc = fsync(fd);
+#else
+  rc = fdatasync(fd);
+#if OS_VXWORKS
+  if( rc==-1 && errno==ENOTSUP ){
+    rc = fsync(fd);
+  }
+#endif /* OS_VXWORKS */
+#endif /* ifdef SQLITE_NO_SYNC elif HAVE_FULLFSYNC */
+
+  if( OS_VXWORKS && rc!= -1 ){
+    rc = 0;
+  }
+  return rc;
+}
+
+/*
+** Open a file descriptor to the directory containing file zFilename.
+** If successful, *pFd is set to the opened file descriptor and
+** SQLITE_OK is returned. If an error occurs, either SQLITE_NOMEM
+** or SQLITE_CANTOPEN is returned and *pFd is set to an undefined
+** value.
+**
+** The directory file descriptor is used for only one thing - to
+** fsync() a directory to make sure file creation and deletion events
+** are flushed to disk.  Such fsyncs are not needed on newer
+** journaling filesystems, but are required on older filesystems.
+**
+** This routine can be overridden using the xSetSysCall interface.
+** The ability to override this routine was added in support of the
+** chromium sandbox.  Opening a directory is a security risk (we are
+** told) so making it overrideable allows the chromium sandbox to
+** replace this routine with a harmless no-op.  To make this routine
+** a no-op, replace it with a stub that returns SQLITE_OK but leaves
+** *pFd set to a negative number.
+**
+** If SQLITE_OK is returned, the caller is responsible for closing
+** the file descriptor *pFd using close().
+*/
+static int openDirectory(const char *zFilename, int *pFd){
+  int ii;
+  int fd = -1;
+  char zDirname[MAX_PATHNAME+1];
+
+  sqlite3_snprintf(MAX_PATHNAME, zDirname, "%s", zFilename);
+  for(ii=(int)strlen(zDirname); ii>0 && zDirname[ii]!='/'; ii--);
+  if( ii>0 ){
+    zDirname[ii] = '\0';
+  }else{
+    if( zDirname[0]!='/' ) zDirname[0] = '.';
+    zDirname[1] = 0;
+  }
+  fd = robust_open(zDirname, O_RDONLY|O_BINARY, 0);
+  if( fd>=0 ){
+    OSTRACE(("OPENDIR %-3d %s\n", fd, zDirname));
+  }
+  *pFd = fd;
+  if( fd>=0 ) return SQLITE_OK;
+  return unixLogError(SQLITE_CANTOPEN_BKPT, "openDirectory", zDirname);
+}
+
+/*
+** Make sure all writes to a particular file are committed to disk.
+**
+** If dataOnly==0 then both the file itself and its metadata (file
+** size, access time, etc) are synced.  If dataOnly!=0 then only the
+** file data is synced.
+**
+** Under Unix, also make sure that the directory entry for the file
+** has been created by fsync-ing the directory that contains the file.
+** If we do not do this and we encounter a power failure, the directory
+** entry for the journal might not exist after we reboot.  The next
+** SQLite to access the file will not know that the journal exists (because
+** the directory entry for the journal was never created) and the transaction
+** will not roll back - possibly leading to database corruption.
+*/
+static int unixSync(sqlite3_file *id, int flags){
+  int rc;
+  unixFile *pFile = (unixFile*)id;
+
+  int isDataOnly = (flags&SQLITE_SYNC_DATAONLY);
+  int isFullsync = (flags&0x0F)==SQLITE_SYNC_FULL;
+
+  /* Check that one of SQLITE_SYNC_NORMAL or FULL was passed */
+  assert((flags&0x0F)==SQLITE_SYNC_NORMAL
+      || (flags&0x0F)==SQLITE_SYNC_FULL
+  );
+
+  /* Unix cannot, but some systems may return SQLITE_FULL from here. This
+  ** line is to test that doing so does not cause any problems.
+  */
+  SimulateDiskfullError( return SQLITE_FULL );
+
+  assert( pFile );
+  OSTRACE(("SYNC    %-3d\n", pFile->h));
+  rc = full_fsync(pFile->h, isFullsync, isDataOnly);
+  SimulateIOError( rc=1 );
+  if( rc ){
+    storeLastErrno(pFile, errno);
+    return unixLogError(SQLITE_IOERR_FSYNC, "full_fsync", pFile->zPath);
+  }
+
+  /* Also fsync the directory containing the file if the DIRSYNC flag
+  ** is set.  This is a one-time occurrence.  Many systems (examples: AIX)
+  ** are unable to fsync a directory, so ignore errors on the fsync.
+  */
+  if( pFile->ctrlFlags & UNIXFILE_DIRSYNC ){
+    int dirfd;
+    OSTRACE(("DIRSYNC %s (have_fullfsync=%d fullsync=%d)\n", pFile->zPath,
+            HAVE_FULLFSYNC, isFullsync));
+    rc = osOpenDirectory(pFile->zPath, &dirfd);
+    if( rc==SQLITE_OK ){
+      full_fsync(dirfd, 0, 0);
+      robust_close(pFile, dirfd, __LINE__);
+    }else{
+      assert( rc==SQLITE_CANTOPEN );
+      rc = SQLITE_OK;
+    }
+    pFile->ctrlFlags &= ~UNIXFILE_DIRSYNC;
+  }
+  return rc;
+}
+
+/*
+** Truncate an open file to a specified size
+*/
+static int unixTruncate(sqlite3_file *id, i64 nByte){
+  unixFile *pFile = (unixFile *)id;
+  int rc;
+  assert( pFile );
+  SimulateIOError( return SQLITE_IOERR_TRUNCATE );
+
+  /* If the user has configured a chunk-size for this file, truncate the
+  ** file so that it consists of an integer number of chunks (i.e. the
+  ** actual file size after the operation may be larger than the requested
+  ** size).
+  */
+  if( pFile->szChunk>0 ){
+    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
+  }
+
+  rc = robust_ftruncate(pFile->h, nByte);
+  if( rc ){
+    storeLastErrno(pFile, errno);
+    return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath);
+  }else{
+#ifdef SQLITE_DEBUG
+    /* If we are doing a normal write to a database file (as opposed to
+    ** doing a hot-journal rollback or a write to some file other than a
+    ** normal database file) and we truncate the file to zero length,
+    ** that effectively updates the change counter.  This might happen
+    ** when restoring a database using the backup API from a zero-length
+    ** source.
+    */
+    if( pFile->inNormalWrite && nByte==0 ){
+      pFile->transCntrChng = 1;
+    }
+#endif
+
+#if SQLITE_MAX_MMAP_SIZE>0
+    /* If the file was just truncated to a size smaller than the currently
+    ** mapped region, reduce the effective mapping size as well. SQLite will
+    ** use read() and write() to access data beyond this point from now on.
+    */
+    if( nByte<pFile->mmapSize ){
+      pFile->mmapSize = nByte;
+    }
+#endif
+
+    return SQLITE_OK;
+  }
+}
+
+/*
+** Determine the current size of a file in bytes
+*/
+static int unixFileSize(sqlite3_file *id, i64 *pSize){
+  int rc;
+  struct stat buf;
+  assert( id );
+  rc = osFstat(((unixFile*)id)->h, &buf);
+  SimulateIOError( rc=1 );
+  if( rc!=0 ){
+    storeLastErrno((unixFile*)id, errno);
+    return SQLITE_IOERR_FSTAT;
+  }
+  *pSize = buf.st_size;
+
+  /* When opening a zero-size database, the findInodeInfo() procedure
+  ** writes a single byte into that file in order to work around a bug
+  ** in the OS-X msdos filesystem.  In order to avoid problems with upper
+  ** layers, we need to report this file size as zero even though it is
+  ** really 1.   Ticket #3260.
+  */
+  if( *pSize==1 ) *pSize = 0;
+
+
+  return SQLITE_OK;
+}
+
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+/*
+** Handler for proxy-locking file-control verbs.  Defined below in the
+** proxying locking division.
+*/
+static int proxyFileControl(sqlite3_file*,int,void*);
+#endif
+
+/*
+** This function is called to handle the SQLITE_FCNTL_SIZE_HINT
+** file-control operation.  Enlarge the database to nBytes in size
+** (rounded up to the next chunk-size).  If the database is already
+** nBytes or larger, this routine is a no-op.
+*/
+static int fcntlSizeHint(unixFile *pFile, i64 nByte){
+  if( pFile->szChunk>0 ){
+    i64 nSize;                    /* Required file size */
+    struct stat buf;              /* Used to hold return values of fstat() */
+
+    if( osFstat(pFile->h, &buf) ){
+      return SQLITE_IOERR_FSTAT;
+    }
+
+    nSize = ((nByte+pFile->szChunk-1) / pFile->szChunk) * pFile->szChunk;
+    if( nSize>(i64)buf.st_size ){
+
+#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE
+      /* The code below is handling the return value of osFallocate()
+      ** correctly. posix_fallocate() is defined to "returns zero on success,
+      ** or an error number on  failure". See the manpage for details. */
+      int err;
+      do{
+        err = osFallocate(pFile->h, buf.st_size, nSize-buf.st_size);
+      }while( err==EINTR );
+      if( err && err!=EINVAL ) return SQLITE_IOERR_WRITE;
+#else
+      /* If the OS does not have posix_fallocate(), fake it. Write a
+      ** single byte to the last byte in each block that falls entirely
+      ** within the extended region. Then, if required, a single byte
+      ** at offset (nSize-1), to set the size of the file correctly.
+      ** This is a similar technique to that used by glibc on systems
+      ** that do not have a real fallocate() call.
+      */
+      int nBlk = buf.st_blksize;  /* File-system block size */
+      int nWrite = 0;             /* Number of bytes written by seekAndWrite */
+      i64 iWrite;                 /* Next offset to write to */
+
+      iWrite = (buf.st_size/nBlk)*nBlk + nBlk - 1;
+      assert( iWrite>=buf.st_size );
+      assert( ((iWrite+1)%nBlk)==0 );
+      for(/*no-op*/; iWrite<nSize+nBlk-1; iWrite+=nBlk ){
+        if( iWrite>=nSize ) iWrite = nSize - 1;
+        nWrite = seekAndWrite(pFile, iWrite, "", 1);
+        if( nWrite!=1 ) return SQLITE_IOERR_WRITE;
+      }
+#endif
+    }
+  }
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFile->mmapSizeMax>0 && nByte>pFile->mmapSize ){
+    int rc;
+    if( pFile->szChunk<=0 ){
+      if( robust_ftruncate(pFile->h, nByte) ){
+        storeLastErrno(pFile, errno);
+        return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath);
+      }
+    }
+
+    rc = unixMapfile(pFile, nByte);
+    return rc;
+  }
+#endif
+
+  return SQLITE_OK;
+}
+
+/*
+** If *pArg is initially negative then this is a query.  Set *pArg to
+** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
+**
+** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
+*/
+static void unixModeBit(unixFile *pFile, unsigned char mask, int *pArg){
+  if( *pArg<0 ){
+    *pArg = (pFile->ctrlFlags & mask)!=0;
+  }else if( (*pArg)==0 ){
+    pFile->ctrlFlags &= ~mask;
+  }else{
+    pFile->ctrlFlags |= mask;
+  }
+}
+
+/* Forward declaration */
+static int unixGetTempname(int nBuf, char *zBuf);
+#if !defined(SQLITE_WASI) && !defined(SQLITE_OMIT_WAL)
+ static int unixFcntlExternalReader(unixFile*, int*);
+#endif
+
+/*
+** Information and control of an open file handle.
+*/
+static int unixFileControl(sqlite3_file *id, int op, void *pArg){
+  unixFile *pFile = (unixFile*)id;
+  switch( op ){
+#if defined(__linux__) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+    case SQLITE_FCNTL_BEGIN_ATOMIC_WRITE: {
+      int rc = osIoctl(pFile->h, F2FS_IOC_START_ATOMIC_WRITE);
+      return rc ? SQLITE_IOERR_BEGIN_ATOMIC : SQLITE_OK;
+    }
+    case SQLITE_FCNTL_COMMIT_ATOMIC_WRITE: {
+      int rc = osIoctl(pFile->h, F2FS_IOC_COMMIT_ATOMIC_WRITE);
+      return rc ? SQLITE_IOERR_COMMIT_ATOMIC : SQLITE_OK;
+    }
+    case SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE: {
+      int rc = osIoctl(pFile->h, F2FS_IOC_ABORT_VOLATILE_WRITE);
+      return rc ? SQLITE_IOERR_ROLLBACK_ATOMIC : SQLITE_OK;
+    }
+#endif /* __linux__ && SQLITE_ENABLE_BATCH_ATOMIC_WRITE */
+
+    case SQLITE_FCNTL_NULL_IO: {
+      osClose(pFile->h);
+      pFile->h = -1;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_LOCKSTATE: {
+      *(int*)pArg = pFile->eFileLock;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_LAST_ERRNO: {
+      *(int*)pArg = pFile->lastErrno;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_CHUNK_SIZE: {
+      pFile->szChunk = *(int *)pArg;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_SIZE_HINT: {
+      int rc;
+      SimulateIOErrorBenign(1);
+      rc = fcntlSizeHint(pFile, *(i64 *)pArg);
+      SimulateIOErrorBenign(0);
+      return rc;
+    }
+    case SQLITE_FCNTL_PERSIST_WAL: {
+      unixModeBit(pFile, UNIXFILE_PERSIST_WAL, (int*)pArg);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
+      unixModeBit(pFile, UNIXFILE_PSOW, (int*)pArg);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_VFSNAME: {
+      *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName);
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_TEMPFILENAME: {
+      char *zTFile = sqlite3_malloc64( pFile->pVfs->mxPathname );
+      if( zTFile ){
+        unixGetTempname(pFile->pVfs->mxPathname, zTFile);
+        *(char**)pArg = zTFile;
+      }
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_HAS_MOVED: {
+      *(int*)pArg = fileHasMoved(pFile);
+      return SQLITE_OK;
+    }
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    case SQLITE_FCNTL_LOCK_TIMEOUT: {
+      int iOld = pFile->iBusyTimeout;
+#if SQLITE_ENABLE_SETLK_TIMEOUT==1
+      pFile->iBusyTimeout = *(int*)pArg;
+#elif SQLITE_ENABLE_SETLK_TIMEOUT==2
+      pFile->iBusyTimeout = !!(*(int*)pArg);
+#else
+# error "SQLITE_ENABLE_SETLK_TIMEOUT must be set to 1 or 2"
+#endif
+      *(int*)pArg = iOld;
+      return SQLITE_OK;
+    }
+#endif
+#if SQLITE_MAX_MMAP_SIZE>0
+    case SQLITE_FCNTL_MMAP_SIZE: {
+      i64 newLimit = *(i64*)pArg;
+      int rc = SQLITE_OK;
+      if( newLimit>sqlite3GlobalConfig.mxMmap ){
+        newLimit = sqlite3GlobalConfig.mxMmap;
+      }
+
+      /* The value of newLimit may be eventually cast to (size_t) and passed
+      ** to mmap(). Restrict its value to 2GB if (size_t) is not at least a
+      ** 64-bit type. */
+      if( newLimit>0 && sizeof(size_t)<8 ){
+        newLimit = (newLimit & 0x7FFFFFFF);
+      }
+
+      *(i64*)pArg = pFile->mmapSizeMax;
+      if( newLimit>=0 && newLimit!=pFile->mmapSizeMax && pFile->nFetchOut==0 ){
+        pFile->mmapSizeMax = newLimit;
+        if( pFile->mmapSize>0 ){
+          unixUnmapfile(pFile);
+          rc = unixMapfile(pFile, -1);
+        }
+      }
+      return rc;
+    }
+#endif
+#ifdef SQLITE_DEBUG
+    /* The pager calls this method to signal that it has done
+    ** a rollback and that the database is therefore unchanged and
+    ** it hence it is OK for the transaction change counter to be
+    ** unchanged.
+    */
+    case SQLITE_FCNTL_DB_UNCHANGED: {
+      ((unixFile*)id)->dbUpdate = 0;
+      return SQLITE_OK;
+    }
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+    case SQLITE_FCNTL_SET_LOCKPROXYFILE:
+    case SQLITE_FCNTL_GET_LOCKPROXYFILE: {
+      return proxyFileControl(id,op,pArg);
+    }
+#endif /* SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) */
+
+    case SQLITE_FCNTL_EXTERNAL_READER: {
+#if !defined(SQLITE_WASI) && !defined(SQLITE_OMIT_WAL)
+      return unixFcntlExternalReader((unixFile*)id, (int*)pArg);
+#else
+      *(int*)pArg = 0;
+      return SQLITE_OK;
+#endif
+    }
+  }
+  return SQLITE_NOTFOUND;
+}
+
+/*
+** If pFd->sectorSize is non-zero when this function is called, it is a
+** no-op. Otherwise, the values of pFd->sectorSize and
+** pFd->deviceCharacteristics are set according to the file-system
+** characteristics.
+**
+** There are two versions of this function. One for QNX and one for all
+** other systems.
+*/
+#ifndef __QNXNTO__
+static void setDeviceCharacteristics(unixFile *pFd){
+  assert( pFd->deviceCharacteristics==0 || pFd->sectorSize!=0 );
+  if( pFd->sectorSize==0 ){
+#if defined(__linux__) && defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+    int res;
+    u32 f = 0;
+
+    /* Check for support for F2FS atomic batch writes. */
+    res = osIoctl(pFd->h, F2FS_IOC_GET_FEATURES, &f);
+    if( res==0 && (f & F2FS_FEATURE_ATOMIC_WRITE) ){
+      pFd->deviceCharacteristics = SQLITE_IOCAP_BATCH_ATOMIC;
+    }
+#endif /* __linux__ && SQLITE_ENABLE_BATCH_ATOMIC_WRITE */
+
+    /* Set the POWERSAFE_OVERWRITE flag if requested. */
+    if( pFd->ctrlFlags & UNIXFILE_PSOW ){
+      pFd->deviceCharacteristics |= SQLITE_IOCAP_POWERSAFE_OVERWRITE;
+    }
+    pFd->deviceCharacteristics |= SQLITE_IOCAP_SUBPAGE_READ;
+
+    pFd->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE;
+  }
+}
+#else
+#include <sys/dcmd_blk.h>
+#include <sys/statvfs.h>
+static void setDeviceCharacteristics(unixFile *pFile){
+  if( pFile->sectorSize == 0 ){
+    struct statvfs fsInfo;
+
+    /* Set defaults for non-supported filesystems */
+    pFile->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE;
+    pFile->deviceCharacteristics = 0;
+    if( fstatvfs(pFile->h, &fsInfo) == -1 ) {
+      return;
+    }
+
+    if( !strcmp(fsInfo.f_basetype, "tmp") ) {
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        SQLITE_IOCAP_ATOMIC4K |       /* All ram filesystem writes are atomic */
+        SQLITE_IOCAP_SAFE_APPEND |    /* growing the file does not occur until
+                                      ** the write succeeds */
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else if( strstr(fsInfo.f_basetype, "etfs") ){
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        /* etfs cluster size writes are atomic */
+        (pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) |
+        SQLITE_IOCAP_SAFE_APPEND |    /* growing the file does not occur until
+                                      ** the write succeeds */
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else if( !strcmp(fsInfo.f_basetype, "qnx6") ){
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        SQLITE_IOCAP_ATOMIC |         /* All filesystem writes are atomic */
+        SQLITE_IOCAP_SAFE_APPEND |    /* growing the file does not occur until
+                                      ** the write succeeds */
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else if( !strcmp(fsInfo.f_basetype, "qnx4") ){
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        /* full bitset of atomics from max sector size and smaller */
+        (((pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) << 1) - 2) |
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else if( strstr(fsInfo.f_basetype, "dos") ){
+      pFile->sectorSize = fsInfo.f_bsize;
+      pFile->deviceCharacteristics =
+        /* full bitset of atomics from max sector size and smaller */
+        (((pFile->sectorSize / 512 * SQLITE_IOCAP_ATOMIC512) << 1) - 2) |
+        SQLITE_IOCAP_SEQUENTIAL |     /* The ram filesystem has no write behind
+                                      ** so it is ordered */
+        0;
+    }else{
+      pFile->deviceCharacteristics =
+        SQLITE_IOCAP_ATOMIC512 |      /* blocks are atomic */
+        SQLITE_IOCAP_SAFE_APPEND |    /* growing the file does not occur until
+                                      ** the write succeeds */
+        0;
+    }
+  }
+  /* Last chance verification.  If the sector size isn't a multiple of 512
+  ** then it isn't valid.*/
+  if( pFile->sectorSize % 512 != 0 ){
+    pFile->deviceCharacteristics = 0;
+    pFile->sectorSize = SQLITE_DEFAULT_SECTOR_SIZE;
+  }
+}
+#endif
+
+/*
+** Return the sector size in bytes of the underlying block device for
+** the specified file. This is almost always 512 bytes, but may be
+** larger for some devices.
+**
+** SQLite code assumes this function cannot fail. It also assumes that
+** if two files are created in the same file-system directory (i.e.
+** a database and its journal file) that the sector size will be the
+** same for both.
+*/
+static int unixSectorSize(sqlite3_file *id){
+  unixFile *pFd = (unixFile*)id;
+  setDeviceCharacteristics(pFd);
+  return pFd->sectorSize;
+}
+
+/*
+** Return the device characteristics for the file.
+**
+** This VFS is set up to return SQLITE_IOCAP_POWERSAFE_OVERWRITE by default.
+** However, that choice is controversial since technically the underlying
+** file system does not always provide powersafe overwrites.  (In other
+** words, after a power-loss event, parts of the file that were never
+** written might end up being altered.)  However, non-PSOW behavior is very,
+** very rare.  And asserting PSOW makes a large reduction in the amount
+** of required I/O for journaling, since a lot of padding is eliminated.
+**  Hence, while POWERSAFE_OVERWRITE is on by default, there is a file-control
+** available to turn it off and URI query parameter available to turn it off.
+*/
+static int unixDeviceCharacteristics(sqlite3_file *id){
+  unixFile *pFd = (unixFile*)id;
+  setDeviceCharacteristics(pFd);
+  return pFd->deviceCharacteristics;
+}
+
+#if !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
+
+/*
+** Return the system page size.
+**
+** This function should not be called directly by other code in this file.
+** Instead, it should be called via macro osGetpagesize().
+*/
+static int unixGetpagesize(void){
+#if OS_VXWORKS
+  return 1024;
+#elif defined(_BSD_SOURCE)
+  return getpagesize();
+#else
+  return (int)sysconf(_SC_PAGESIZE);
+#endif
+}
+
+#endif /* !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0 */
+
+#if !defined(SQLITE_WASI) && !defined(SQLITE_OMIT_WAL)
+
+/*
+** Object used to represent an shared memory buffer.
+**
+** When multiple threads all reference the same wal-index, each thread
+** has its own unixShm object, but they all point to a single instance
+** of this unixShmNode object.  In other words, each wal-index is opened
+** only once per process.
+**
+** Each unixShmNode object is connected to a single unixInodeInfo object.
+** We could coalesce this object into unixInodeInfo, but that would mean
+** every open file that does not use shared memory (in other words, most
+** open files) would have to carry around this extra information.  So
+** the unixInodeInfo object contains a pointer to this unixShmNode object
+** and the unixShmNode object is created only when needed.
+**
+** unixMutexHeld() must be true when creating or destroying
+** this object or while reading or writing the following fields:
+**
+**      nRef
+**
+** The following fields are read-only after the object is created:
+**
+**      hShm
+**      zFilename
+**
+** Either unixShmNode.pShmMutex must be held or unixShmNode.nRef==0 and
+** unixMutexHeld() is true when reading or writing any other field
+** in this structure.
+**
+** aLock[SQLITE_SHM_NLOCK]:
+**   This array records the various locks held by clients on each of the
+**   SQLITE_SHM_NLOCK slots. If the aLock[] entry is set to 0, then no
+**   locks are held by the process on this slot. If it is set to -1, then
+**   some client holds an EXCLUSIVE lock on the locking slot. If the aLock[]
+**   value is set to a positive value, then it is the number of shared
+**   locks currently held on the slot.
+**
+** aMutex[SQLITE_SHM_NLOCK]:
+**   Normally, when SQLITE_ENABLE_SETLK_TIMEOUT is not defined, mutex
+**   pShmMutex is used to protect the aLock[] array and the right to
+**   call fcntl() on unixShmNode.hShm to obtain or release locks.
+**
+**   If SQLITE_ENABLE_SETLK_TIMEOUT is defined though, we use an array
+**   of mutexes - one for each locking slot. To read or write locking
+**   slot aLock[iSlot], the caller must hold the corresponding mutex
+**   aMutex[iSlot]. Similarly, to call fcntl() to obtain or release a
+**   lock corresponding to slot iSlot, mutex aMutex[iSlot] must be held.
+*/
+struct unixShmNode {
+  unixInodeInfo *pInode;     /* unixInodeInfo that owns this SHM node */
+  sqlite3_mutex *pShmMutex;  /* Mutex to access this object */
+  char *zFilename;           /* Name of the mmapped file */
+  int hShm;                  /* Open file descriptor */
+  int szRegion;              /* Size of shared-memory regions */
+  u16 nRegion;               /* Size of array apRegion */
+  u8 isReadonly;             /* True if read-only */
+  u8 isUnlocked;             /* True if no DMS lock held */
+  char **apRegion;           /* Array of mapped shared-memory regions */
+  int nRef;                  /* Number of unixShm objects pointing to this */
+  unixShm *pFirst;           /* All unixShm objects pointing to this */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  sqlite3_mutex *aMutex[SQLITE_SHM_NLOCK];
+#endif
+  int aLock[SQLITE_SHM_NLOCK];  /* # shared locks on slot, -1==excl lock */
+#ifdef SQLITE_DEBUG
+  u8 nextShmId;              /* Next available unixShm.id value */
+#endif
+};
+
+/*
+** Structure used internally by this VFS to record the state of an
+** open shared memory connection.
+**
+** The following fields are initialized when this object is created and
+** are read-only thereafter:
+**
+**    unixShm.pShmNode
+**    unixShm.id
+**
+** All other fields are read/write.  The unixShm.pShmNode->pShmMutex must
+** be held while accessing any read/write fields.
+*/
+struct unixShm {
+  unixShmNode *pShmNode;     /* The underlying unixShmNode object */
+  unixShm *pNext;            /* Next unixShm with the same unixShmNode */
+  u8 hasMutex;               /* True if holding the unixShmNode->pShmMutex */
+  u8 id;                     /* Id of this connection within its unixShmNode */
+  u16 sharedMask;            /* Mask of shared locks held */
+  u16 exclMask;              /* Mask of exclusive locks held */
+};
+
+/*
+** Constants used for locking
+*/
+#define UNIX_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)         /* first lock byte */
+#define UNIX_SHM_DMS    (UNIX_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */
+
+/*
+** Use F_GETLK to check whether or not there are any readers with open
+** wal-mode transactions in other processes on database file pFile. If
+** no error occurs, return SQLITE_OK and set (*piOut) to 1 if there are
+** such transactions, or 0 otherwise. If an error occurs, return an
+** SQLite error code. The final value of *piOut is undefined in this
+** case.
+*/
+static int unixFcntlExternalReader(unixFile *pFile, int *piOut){
+  int rc = SQLITE_OK;
+  *piOut = 0;
+  if( pFile->pShm){
+    unixShmNode *pShmNode = pFile->pShm->pShmNode;
+    struct flock f;
+
+    memset(&f, 0, sizeof(f));
+    f.l_type = F_WRLCK;
+    f.l_whence = SEEK_SET;
+    f.l_start = UNIX_SHM_BASE + 3;
+    f.l_len = SQLITE_SHM_NLOCK - 3;
+
+    sqlite3_mutex_enter(pShmNode->pShmMutex);
+    if( osFcntl(pShmNode->hShm, F_GETLK, &f)<0 ){
+      rc = SQLITE_IOERR_LOCK;
+    }else{
+      *piOut = (f.l_type!=F_UNLCK);
+    }
+    sqlite3_mutex_leave(pShmNode->pShmMutex);
+  }
+
+  return rc;
+}
+
+
+/*
+** Apply posix advisory locks for all bytes from ofst through ofst+n-1.
+**
+** Locks block if the mask is exactly UNIX_SHM_C and are non-blocking
+** otherwise.
+*/
+static int unixShmSystemLock(
+  unixFile *pFile,       /* Open connection to the WAL file */
+  int lockType,          /* F_UNLCK, F_RDLCK, or F_WRLCK */
+  int ofst,              /* First byte of the locking range */
+  int n                  /* Number of bytes to lock */
+){
+  unixShmNode *pShmNode; /* Apply locks to this open shared-memory segment */
+  struct flock f;        /* The posix advisory locking structure */
+  int rc = SQLITE_OK;    /* Result code form fcntl() */
+
+  pShmNode = pFile->pInode->pShmNode;
+
+  /* Assert that the parameters are within expected range and that the
+  ** correct mutex or mutexes are held. */
+  assert( pShmNode->nRef>=0 );
+  assert( (ofst==UNIX_SHM_DMS && n==1)
+       || (ofst>=UNIX_SHM_BASE && ofst+n<=(UNIX_SHM_BASE+SQLITE_SHM_NLOCK))
+  );
+  if( ofst==UNIX_SHM_DMS ){
+    assert( pShmNode->nRef>0 || unixMutexHeld() );
+    assert( pShmNode->nRef==0 || sqlite3_mutex_held(pShmNode->pShmMutex) );
+  }else{
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    int ii;
+    for(ii=ofst-UNIX_SHM_BASE; ii<ofst-UNIX_SHM_BASE+n; ii++){
+      assert( sqlite3_mutex_held(pShmNode->aMutex[ii]) );
+    }
+#else
+    assert( sqlite3_mutex_held(pShmNode->pShmMutex) );
+    assert( pShmNode->nRef>0 );
+#endif
+  }
+
+  /* Shared locks never span more than one byte */
+  assert( n==1 || lockType!=F_RDLCK );
+
+  /* Locks are within range */
+  assert( n>=1 && n<=SQLITE_SHM_NLOCK );
+  assert( ofst>=UNIX_SHM_BASE && ofst<=(UNIX_SHM_DMS+SQLITE_SHM_NLOCK) );
+
+  if( pShmNode->hShm>=0 ){
+    int res;
+    /* Initialize the locking parameters */
+    f.l_type = lockType;
+    f.l_whence = SEEK_SET;
+    f.l_start = ofst;
+    f.l_len = n;
+    res = osSetPosixAdvisoryLock(pShmNode->hShm, &f, pFile);
+    if( res==-1 ){
+#if defined(SQLITE_ENABLE_SETLK_TIMEOUT) && SQLITE_ENABLE_SETLK_TIMEOUT==1
+      rc = (pFile->iBusyTimeout ? SQLITE_BUSY_TIMEOUT : SQLITE_BUSY);
+#else
+      rc = SQLITE_BUSY;
+#endif
+    }
+  }
+
+  /* Do debug tracing */
+#ifdef SQLITE_DEBUG
+  OSTRACE(("SHM-LOCK "));
+  if( rc==SQLITE_OK ){
+    if( lockType==F_UNLCK ){
+      OSTRACE(("unlock %d..%d ok\n", ofst, ofst+n-1));
+    }else if( lockType==F_RDLCK ){
+      OSTRACE(("read-lock %d..%d ok\n", ofst, ofst+n-1));
+    }else{
+      assert( lockType==F_WRLCK );
+      OSTRACE(("write-lock %d..%d ok\n", ofst, ofst+n-1));
+    }
+  }else{
+    if( lockType==F_UNLCK ){
+      OSTRACE(("unlock %d..%d failed\n", ofst, ofst+n-1));
+    }else if( lockType==F_RDLCK ){
+      OSTRACE(("read-lock %d..%d failed\n", ofst, ofst+n-1));
+    }else{
+      assert( lockType==F_WRLCK );
+      OSTRACE(("write-lock %d..%d failed\n", ofst, ofst+n-1));
+    }
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** Return the minimum number of 32KB shm regions that should be mapped at
+** a time, assuming that each mapping must be an integer multiple of the
+** current system page-size.
+**
+** Usually, this is 1. The exception seems to be systems that are configured
+** to use 64KB pages - in this case each mapping must cover at least two
+** shm regions.
+*/
+static int unixShmRegionPerMap(void){
+  int shmsz = 32*1024;            /* SHM region size */
+  int pgsz = osGetpagesize();   /* System page size */
+  assert( ((pgsz-1)&pgsz)==0 );   /* Page size must be a power of 2 */
+  if( pgsz<shmsz ) return 1;
+  return pgsz/shmsz;
+}
+
+/*
+** Purge the unixShmNodeList list of all entries with unixShmNode.nRef==0.
+**
+** This is not a VFS shared-memory method; it is a utility function called
+** by VFS shared-memory methods.
+*/
+static void unixShmPurge(unixFile *pFd){
+  unixShmNode *p = pFd->pInode->pShmNode;
+  assert( unixMutexHeld() );
+  if( p && ALWAYS(p->nRef==0) ){
+    int nShmPerMap = unixShmRegionPerMap();
+    int i;
+    assert( p->pInode==pFd->pInode );
+    sqlite3_mutex_free(p->pShmMutex);
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    for(i=0; i<SQLITE_SHM_NLOCK; i++){
+      sqlite3_mutex_free(p->aMutex[i]);
+    }
+#endif
+    for(i=0; i<p->nRegion; i+=nShmPerMap){
+      if( p->hShm>=0 ){
+        osMunmap(p->apRegion[i], p->szRegion);
+      }else{
+        sqlite3_free(p->apRegion[i]);
+      }
+    }
+    sqlite3_free(p->apRegion);
+    if( p->hShm>=0 ){
+      robust_close(pFd, p->hShm, __LINE__);
+      p->hShm = -1;
+    }
+    p->pInode->pShmNode = 0;
+    sqlite3_free(p);
+  }
+}
+
+/*
+** The DMS lock has not yet been taken on shm file pShmNode. Attempt to
+** take it now. Return SQLITE_OK if successful, or an SQLite error
+** code otherwise.
+**
+** If the DMS cannot be locked because this is a readonly_shm=1
+** connection and no other process already holds a lock, return
+** SQLITE_READONLY_CANTINIT and set pShmNode->isUnlocked=1.
+*/
+static int unixLockSharedMemory(unixFile *pDbFd, unixShmNode *pShmNode){
+  struct flock lock;
+  int rc = SQLITE_OK;
+
+  /* Use F_GETLK to determine the locks other processes are holding
+  ** on the DMS byte. If it indicates that another process is holding
+  ** a SHARED lock, then this process may also take a SHARED lock
+  ** and proceed with opening the *-shm file.
+  **
+  ** Or, if no other process is holding any lock, then this process
+  ** is the first to open it. In this case take an EXCLUSIVE lock on the
+  ** DMS byte and truncate the *-shm file to zero bytes in size. Then
+  ** downgrade to a SHARED lock on the DMS byte.
+  **
+  ** If another process is holding an EXCLUSIVE lock on the DMS byte,
+  ** return SQLITE_BUSY to the caller (it will try again). An earlier
+  ** version of this code attempted the SHARED lock at this point. But
+  ** this introduced a subtle race condition: if the process holding
+  ** EXCLUSIVE failed just before truncating the *-shm file, then this
+  ** process might open and use the *-shm file without truncating it.
+  ** And if the *-shm file has been corrupted by a power failure or
+  ** system crash, the database itself may also become corrupt.  */
+  lock.l_whence = SEEK_SET;
+  lock.l_start = UNIX_SHM_DMS;
+  lock.l_len = 1;
+  lock.l_type = F_WRLCK;
+  if( osFcntl(pShmNode->hShm, F_GETLK, &lock)!=0 ) {
+    rc = SQLITE_IOERR_LOCK;
+  }else if( lock.l_type==F_UNLCK ){
+    if( pShmNode->isReadonly ){
+      pShmNode->isUnlocked = 1;
+      rc = SQLITE_READONLY_CANTINIT;
+    }else{
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+      /* Do not use a blocking lock here. If the lock cannot be obtained
+      ** immediately, it means some other connection is truncating the
+      ** *-shm file. And after it has done so, it will not release its
+      ** lock, but only downgrade it to a shared lock. So no point in
+      ** blocking here. The call below to obtain the shared DMS lock may
+      ** use a blocking lock. */
+      int iSaveTimeout = pDbFd->iBusyTimeout;
+      pDbFd->iBusyTimeout = 0;
+#endif
+      rc = unixShmSystemLock(pDbFd, F_WRLCK, UNIX_SHM_DMS, 1);
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+      pDbFd->iBusyTimeout = iSaveTimeout;
+#endif
+      /* The first connection to attach must truncate the -shm file.  We
+      ** truncate to 3 bytes (an arbitrary small number, less than the
+      ** -shm header size) rather than 0 as a system debugging aid, to
+      ** help detect if a -shm file truncation is legitimate or is the work
+      ** or a rogue process. */
+      if( rc==SQLITE_OK && robust_ftruncate(pShmNode->hShm, 3) ){
+        rc = unixLogError(SQLITE_IOERR_SHMOPEN,"ftruncate",pShmNode->zFilename);
+      }
+    }
+  }else if( lock.l_type==F_WRLCK ){
+    rc = SQLITE_BUSY;
+  }
+
+  if( rc==SQLITE_OK ){
+    assert( lock.l_type==F_UNLCK || lock.l_type==F_RDLCK );
+    rc = unixShmSystemLock(pDbFd, F_RDLCK, UNIX_SHM_DMS, 1);
+  }
+  return rc;
+}
+
+/*
+** Open a shared-memory area associated with open database file pDbFd.
+** This particular implementation uses mmapped files.
+**
+** The file used to implement shared-memory is in the same directory
+** as the open database file and has the same name as the open database
+** file with the "-shm" suffix added.  For example, if the database file
+** is "/home/user1/config.db" then the file that is created and mmapped
+** for shared memory will be called "/home/user1/config.db-shm".
+**
+** Another approach to is to use files in /dev/shm or /dev/tmp or an
+** some other tmpfs mount. But if a file in a different directory
+** from the database file is used, then differing access permissions
+** or a chroot() might cause two different processes on the same
+** database to end up using different files for shared memory -
+** meaning that their memory would not really be shared - resulting
+** in database corruption.  Nevertheless, this tmpfs file usage
+** can be enabled at compile-time using -DSQLITE_SHM_DIRECTORY="/dev/shm"
+** or the equivalent.  The use of the SQLITE_SHM_DIRECTORY compile-time
+** option results in an incompatible build of SQLite;  builds of SQLite
+** that with differing SQLITE_SHM_DIRECTORY settings attempt to use the
+** same database file at the same time, database corruption will likely
+** result. The SQLITE_SHM_DIRECTORY compile-time option is considered
+** "unsupported" and may go away in a future SQLite release.
+**
+** When opening a new shared-memory file, if no other instances of that
+** file are currently open, in this process or in other processes, then
+** the file must be truncated to zero length or have its header cleared.
+**
+** If the original database file (pDbFd) is using the "unix-excl" VFS
+** that means that an exclusive lock is held on the database file and
+** that no other processes are able to read or write the database.  In
+** that case, we do not really need shared memory.  No shared memory
+** file is created.  The shared memory will be simulated with heap memory.
+*/
+static int unixOpenSharedMemory(unixFile *pDbFd){
+  struct unixShm *p = 0;          /* The connection to be opened */
+  struct unixShmNode *pShmNode;   /* The underlying mmapped file */
+  int rc = SQLITE_OK;             /* Result code */
+  unixInodeInfo *pInode;          /* The inode of fd */
+  char *zShm;             /* Name of the file used for SHM */
+  int nShmFilename;               /* Size of the SHM filename in bytes */
+
+  /* Allocate space for the new unixShm object. */
+  p = sqlite3_malloc64( sizeof(*p) );
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  memset(p, 0, sizeof(*p));
+  assert( pDbFd->pShm==0 );
+
+  /* Check to see if a unixShmNode object already exists. Reuse an existing
+  ** one if present. Create a new one if necessary.
+  */
+  assert( unixFileMutexNotheld(pDbFd) );
+  unixEnterMutex();
+  pInode = pDbFd->pInode;
+  pShmNode = pInode->pShmNode;
+  if( pShmNode==0 ){
+    struct stat sStat;                 /* fstat() info for database file */
+#ifndef SQLITE_SHM_DIRECTORY
+    const char *zBasePath = pDbFd->zPath;
+#endif
+
+    /* Call fstat() to figure out the permissions on the database file. If
+    ** a new *-shm file is created, an attempt will be made to create it
+    ** with the same permissions.
+    */
+    if( osFstat(pDbFd->h, &sStat) ){
+      rc = SQLITE_IOERR_FSTAT;
+      goto shm_open_err;
+    }
+
+#ifdef SQLITE_SHM_DIRECTORY
+    nShmFilename = sizeof(SQLITE_SHM_DIRECTORY) + 31;
+#else
+    nShmFilename = 6 + (int)strlen(zBasePath);
+#endif
+    pShmNode = sqlite3_malloc64( sizeof(*pShmNode) + nShmFilename );
+    if( pShmNode==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto shm_open_err;
+    }
+    memset(pShmNode, 0, sizeof(*pShmNode)+nShmFilename);
+    zShm = pShmNode->zFilename = (char*)&pShmNode[1];
+#ifdef SQLITE_SHM_DIRECTORY
+    sqlite3_snprintf(nShmFilename, zShm,
+                     SQLITE_SHM_DIRECTORY "/sqlite-shm-%x-%x",
+                     (u32)sStat.st_ino, (u32)sStat.st_dev);
+#else
+    sqlite3_snprintf(nShmFilename, zShm, "%s-shm", zBasePath);
+    sqlite3FileSuffix3(pDbFd->zPath, zShm);
+#endif
+    pShmNode->hShm = -1;
+    pDbFd->pInode->pShmNode = pShmNode;
+    pShmNode->pInode = pDbFd->pInode;
+    if( sqlite3GlobalConfig.bCoreMutex ){
+      pShmNode->pShmMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+      if( pShmNode->pShmMutex==0 ){
+        rc = SQLITE_NOMEM_BKPT;
+        goto shm_open_err;
+      }
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+      {
+        int ii;
+        for(ii=0; ii<SQLITE_SHM_NLOCK; ii++){
+          pShmNode->aMutex[ii] = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+          if( pShmNode->aMutex[ii]==0 ){
+            rc = SQLITE_NOMEM_BKPT;
+            goto shm_open_err;
+          }
+        }
+      }
+#endif
+    }
+
+    if( pInode->bProcessLock==0 ){
+      if( 0==sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){
+        pShmNode->hShm = robust_open(zShm, O_RDWR|O_CREAT|O_NOFOLLOW,
+                                     (sStat.st_mode&0777));
+      }
+      if( pShmNode->hShm<0 ){
+        pShmNode->hShm = robust_open(zShm, O_RDONLY|O_NOFOLLOW,
+                                     (sStat.st_mode&0777));
+        if( pShmNode->hShm<0 ){
+          rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShm);
+          goto shm_open_err;
+        }
+        pShmNode->isReadonly = 1;
+      }
+
+      /* If this process is running as root, make sure that the SHM file
+      ** is owned by the same user that owns the original database.  Otherwise,
+      ** the original owner will not be able to connect.
+      */
+      robustFchown(pShmNode->hShm, sStat.st_uid, sStat.st_gid);
+
+      rc = unixLockSharedMemory(pDbFd, pShmNode);
+      if( rc!=SQLITE_OK && rc!=SQLITE_READONLY_CANTINIT ) goto shm_open_err;
+    }
+  }
+
+  /* Make the new connection a child of the unixShmNode */
+  p->pShmNode = pShmNode;
+#ifdef SQLITE_DEBUG
+  p->id = pShmNode->nextShmId++;
+#endif
+  pShmNode->nRef++;
+  pDbFd->pShm = p;
+  unixLeaveMutex();
+
+  /* The reference count on pShmNode has already been incremented under
+  ** the cover of the unixEnterMutex() mutex and the pointer from the
+  ** new (struct unixShm) object to the pShmNode has been set. All that is
+  ** left to do is to link the new object into the linked list starting
+  ** at pShmNode->pFirst. This must be done while holding the
+  ** pShmNode->pShmMutex.
+  */
+  sqlite3_mutex_enter(pShmNode->pShmMutex);
+  p->pNext = pShmNode->pFirst;
+  pShmNode->pFirst = p;
+  sqlite3_mutex_leave(pShmNode->pShmMutex);
+  return rc;
+
+  /* Jump here on any error */
+shm_open_err:
+  unixShmPurge(pDbFd);       /* This call frees pShmNode if required */
+  sqlite3_free(p);
+  unixLeaveMutex();
+  return rc;
+}
+
+/*
+** This function is called to obtain a pointer to region iRegion of the
+** shared-memory associated with the database file fd. Shared-memory regions
+** are numbered starting from zero. Each shared-memory region is szRegion
+** bytes in size.
+**
+** If an error occurs, an error code is returned and *pp is set to NULL.
+**
+** Otherwise, if the bExtend parameter is 0 and the requested shared-memory
+** region has not been allocated (by any client, including one running in a
+** separate process), then *pp is set to NULL and SQLITE_OK returned. If
+** bExtend is non-zero and the requested shared-memory region has not yet
+** been allocated, it is allocated by this function.
+**
+** If the shared-memory region has already been allocated or is allocated by
+** this call as described above, then it is mapped into this processes
+** address space (if it is not already), *pp is set to point to the mapped
+** memory and SQLITE_OK returned.
+*/
+static int unixShmMap(
+  sqlite3_file *fd,               /* Handle open on database file */
+  int iRegion,                    /* Region to retrieve */
+  int szRegion,                   /* Size of regions */
+  int bExtend,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Mapped memory */
+){
+  unixFile *pDbFd = (unixFile*)fd;
+  unixShm *p;
+  unixShmNode *pShmNode;
+  int rc = SQLITE_OK;
+  int nShmPerMap = unixShmRegionPerMap();
+  int nReqRegion;
+
+  /* If the shared-memory file has not yet been opened, open it now. */
+  if( pDbFd->pShm==0 ){
+    rc = unixOpenSharedMemory(pDbFd);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  p = pDbFd->pShm;
+  pShmNode = p->pShmNode;
+  sqlite3_mutex_enter(pShmNode->pShmMutex);
+  if( pShmNode->isUnlocked ){
+    rc = unixLockSharedMemory(pDbFd, pShmNode);
+    if( rc!=SQLITE_OK ) goto shmpage_out;
+    pShmNode->isUnlocked = 0;
+  }
+  assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
+  assert( pShmNode->pInode==pDbFd->pInode );
+  assert( pShmNode->hShm>=0 || pDbFd->pInode->bProcessLock==1 );
+  assert( pShmNode->hShm<0 || pDbFd->pInode->bProcessLock==0 );
+
+  /* Minimum number of regions required to be mapped. */
+  nReqRegion = ((iRegion+nShmPerMap) / nShmPerMap) * nShmPerMap;
+
+  if( pShmNode->nRegion<nReqRegion ){
+    char **apNew;                      /* New apRegion[] array */
+    int nByte = nReqRegion*szRegion;   /* Minimum required file size */
+    struct stat sStat;                 /* Used by fstat() */
+
+    pShmNode->szRegion = szRegion;
+
+    if( pShmNode->hShm>=0 ){
+      /* The requested region is not mapped into this processes address space.
+      ** Check to see if it has been allocated (i.e. if the wal-index file is
+      ** large enough to contain the requested region).
+      */
+      if( osFstat(pShmNode->hShm, &sStat) ){
+        rc = SQLITE_IOERR_SHMSIZE;
+        goto shmpage_out;
+      }
+
+      if( sStat.st_size<nByte ){
+        /* The requested memory region does not exist. If bExtend is set to
+        ** false, exit early. *pp will be set to NULL and SQLITE_OK returned.
+        */
+        if( !bExtend ){
+          goto shmpage_out;
+        }
+
+        /* Alternatively, if bExtend is true, extend the file. Do this by
+        ** writing a single byte to the end of each (OS) page being
+        ** allocated or extended. Technically, we need only write to the
+        ** last page in order to extend the file. But writing to all new
+        ** pages forces the OS to allocate them immediately, which reduces
+        ** the chances of SIGBUS while accessing the mapped region later on.
+        */
+        else{
+          static const int pgsz = 4096;
+          int iPg;
+
+          /* Write to the last byte of each newly allocated or extended page */
+          assert( (nByte % pgsz)==0 );
+          for(iPg=(sStat.st_size/pgsz); iPg<(nByte/pgsz); iPg++){
+            int x = 0;
+            if( seekAndWriteFd(pShmNode->hShm, iPg*pgsz + pgsz-1,"",1,&x)!=1 ){
+              const char *zFile = pShmNode->zFilename;
+              rc = unixLogError(SQLITE_IOERR_SHMSIZE, "write", zFile);
+              goto shmpage_out;
+            }
+          }
+        }
+      }
+    }
+
+    /* Map the requested memory region into this processes address space. */
+    apNew = (char **)sqlite3_realloc(
+        pShmNode->apRegion, nReqRegion*sizeof(char *)
+    );
+    if( !apNew ){
+      rc = SQLITE_IOERR_NOMEM_BKPT;
+      goto shmpage_out;
+    }
+    pShmNode->apRegion = apNew;
+    while( pShmNode->nRegion<nReqRegion ){
+      int nMap = szRegion*nShmPerMap;
+      int i;
+      void *pMem;
+      if( pShmNode->hShm>=0 ){
+        pMem = osMmap(0, nMap,
+            pShmNode->isReadonly ? PROT_READ : PROT_READ|PROT_WRITE,
+            MAP_SHARED, pShmNode->hShm, szRegion*(i64)pShmNode->nRegion
+        );
+        if( pMem==MAP_FAILED ){
+          rc = unixLogError(SQLITE_IOERR_SHMMAP, "mmap", pShmNode->zFilename);
+          goto shmpage_out;
+        }
+      }else{
+        pMem = sqlite3_malloc64(nMap);
+        if( pMem==0 ){
+          rc = SQLITE_NOMEM_BKPT;
+          goto shmpage_out;
+        }
+        memset(pMem, 0, nMap);
+      }
+
+      for(i=0; i<nShmPerMap; i++){
+        pShmNode->apRegion[pShmNode->nRegion+i] = &((char*)pMem)[szRegion*i];
+      }
+      pShmNode->nRegion += nShmPerMap;
+    }
+  }
+
+shmpage_out:
+  if( pShmNode->nRegion>iRegion ){
+    *pp = pShmNode->apRegion[iRegion];
+  }else{
+    *pp = 0;
+  }
+  if( pShmNode->isReadonly && rc==SQLITE_OK ) rc = SQLITE_READONLY;
+  sqlite3_mutex_leave(pShmNode->pShmMutex);
+  return rc;
+}
+
+/*
+** Check that the pShmNode->aLock[] array comports with the locking bitmasks
+** held by each client. Return true if it does, or false otherwise. This
+** is to be used in an assert(). e.g.
+**
+**     assert( assertLockingArrayOk(pShmNode) );
+*/
+#ifdef SQLITE_DEBUG
+static int assertLockingArrayOk(unixShmNode *pShmNode){
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  return 1;
+#else
+  unixShm *pX;
+  int aLock[SQLITE_SHM_NLOCK];
+
+  memset(aLock, 0, sizeof(aLock));
+  for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+    int i;
+    for(i=0; i<SQLITE_SHM_NLOCK; i++){
+      if( pX->exclMask & (1<<i) ){
+        assert( aLock[i]==0 );
+        aLock[i] = -1;
+      }else if( pX->sharedMask & (1<<i) ){
+        assert( aLock[i]>=0 );
+        aLock[i]++;
+      }
+    }
+  }
+
+  assert( 0==memcmp(pShmNode->aLock, aLock, sizeof(aLock)) );
+  return (memcmp(pShmNode->aLock, aLock, sizeof(aLock))==0);
+#endif
+}
+#endif
+
+/*
+** Change the lock state for a shared-memory segment.
+**
+** Note that the relationship between SHARED and EXCLUSIVE locks is a little
+** different here than in posix.  In xShmLock(), one can go from unlocked
+** to shared and back or from unlocked to exclusive and back.  But one may
+** not go from shared to exclusive or from exclusive to shared.
+*/
+static int unixShmLock(
+  sqlite3_file *fd,          /* Database file holding the shared memory */
+  int ofst,                  /* First lock to acquire or release */
+  int n,                     /* Number of locks to acquire or release */
+  int flags                  /* What to do with the lock */
+){
+  unixFile *pDbFd = (unixFile*)fd;      /* Connection holding shared memory */
+  unixShm *p;                           /* The shared memory being locked */
+  unixShmNode *pShmNode;                /* The underlying file iNode */
+  int rc = SQLITE_OK;                   /* Result code */
+  u16 mask = (1<<(ofst+n)) - (1<<ofst); /* Mask of locks to take or release */
+  int *aLock;
+
+  p = pDbFd->pShm;
+  if( p==0 ) return SQLITE_IOERR_SHMLOCK;
+  pShmNode = p->pShmNode;
+  if( NEVER(pShmNode==0) ) return SQLITE_IOERR_SHMLOCK;
+  aLock = pShmNode->aLock;
+
+  assert( pShmNode==pDbFd->pInode->pShmNode );
+  assert( pShmNode->pInode==pDbFd->pInode );
+  assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK );
+  assert( n>=1 );
+  assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) );
+  assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 );
+  assert( pShmNode->hShm>=0 || pDbFd->pInode->bProcessLock==1 );
+  assert( pShmNode->hShm<0 || pDbFd->pInode->bProcessLock==0 );
+
+  /* Check that, if this to be a blocking lock, no locks that occur later
+  ** in the following list than the lock being obtained are already held:
+  **
+  **   1. Checkpointer lock (ofst==1).
+  **   2. Write lock (ofst==0).
+  **   3. Read locks (ofst>=3 && ofst<SQLITE_SHM_NLOCK).
+  **
+  ** In other words, if this is a blocking lock, none of the locks that
+  ** occur later in the above list than the lock being obtained may be
+  ** held.
+  **
+  ** It is not permitted to block on the RECOVER lock.
+  */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  {
+    u16 lockMask = (p->exclMask|p->sharedMask);
+    assert( (flags & SQLITE_SHM_UNLOCK) || pDbFd->iBusyTimeout==0 || (
+          (ofst!=2)                                   /* not RECOVER */
+       && (ofst!=1 || lockMask==0 || lockMask==2)
+       && (ofst!=0 || lockMask<3)
+       && (ofst<3  || lockMask<(1<<ofst))
+    ));
+  }
+#endif
+
+  /* Check if there is any work to do. There are three cases:
+  **
+  **    a) An unlock operation where there are locks to unlock,
+  **    b) An shared lock where the requested lock is not already held
+  **    c) An exclusive lock where the requested lock is not already held
+  **
+  ** The SQLite core never requests an exclusive lock that it already holds.
+  ** This is assert()ed below.
+  */
+  assert( flags!=(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK)
+       || 0==(p->exclMask & mask)
+  );
+  if( ((flags & SQLITE_SHM_UNLOCK) && ((p->exclMask|p->sharedMask) & mask))
+   || (flags==(SQLITE_SHM_SHARED|SQLITE_SHM_LOCK) && 0==(p->sharedMask & mask))
+   || (flags==(SQLITE_SHM_EXCLUSIVE|SQLITE_SHM_LOCK))
+  ){
+
+    /* Take the required mutexes. In SETLK_TIMEOUT mode (blocking locks), if
+    ** this is an attempt on an exclusive lock use sqlite3_mutex_try(). If any
+    ** other thread is holding this mutex, then it is either holding or about
+    ** to hold a lock exclusive to the one being requested, and we may
+    ** therefore return SQLITE_BUSY to the caller.
+    **
+    ** Doing this prevents some deadlock scenarios. For example, thread 1 may
+    ** be a checkpointer blocked waiting on the WRITER lock. And thread 2
+    ** may be a normal SQL client upgrading to a write transaction. In this
+    ** case thread 2 does a non-blocking request for the WRITER lock. But -
+    ** if it were to use sqlite3_mutex_enter() then it would effectively
+    ** become a (doomed) blocking request, as thread 2 would block until thread
+    ** 1 obtained WRITER and released the mutex. Since thread 2 already holds
+    ** a lock on a read-locking slot at this point, this breaks the
+    ** anti-deadlock rules (see above).  */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    int iMutex;
+    for(iMutex=ofst; iMutex<ofst+n; iMutex++){
+      if( flags==(SQLITE_SHM_LOCK|SQLITE_SHM_EXCLUSIVE) ){
+        rc = sqlite3_mutex_try(pShmNode->aMutex[iMutex]);
+        if( rc!=SQLITE_OK ) goto leave_shmnode_mutexes;
+      }else{
+        sqlite3_mutex_enter(pShmNode->aMutex[iMutex]);
+      }
+    }
+#else
+    sqlite3_mutex_enter(pShmNode->pShmMutex);
+#endif
+
+    if( ALWAYS(rc==SQLITE_OK) ){
+      if( flags & SQLITE_SHM_UNLOCK ){
+        /* Case (a) - unlock.  */
+        int bUnlock = 1;
+        assert( (p->exclMask & p->sharedMask)==0 );
+        assert( !(flags & SQLITE_SHM_EXCLUSIVE) || (p->exclMask & mask)==mask );
+        assert( !(flags & SQLITE_SHM_SHARED) || (p->sharedMask & mask)==mask );
+
+        /* If this is a SHARED lock being unlocked, it is possible that other
+        ** clients within this process are holding the same SHARED lock. In
+        ** this case, set bUnlock to 0 so that the posix lock is not removed
+        ** from the file-descriptor below.  */
+        if( flags & SQLITE_SHM_SHARED ){
+          assert( n==1 );
+          assert( aLock[ofst]>=1 );
+          if( aLock[ofst]>1 ){
+            bUnlock = 0;
+            aLock[ofst]--;
+            p->sharedMask &= ~mask;
+          }
+        }
+
+        if( bUnlock ){
+          rc = unixShmSystemLock(pDbFd, F_UNLCK, ofst+UNIX_SHM_BASE, n);
+          if( rc==SQLITE_OK ){
+            memset(&aLock[ofst], 0, sizeof(int)*n);
+            p->sharedMask &= ~mask;
+            p->exclMask &= ~mask;
+          }
+        }
+      }else if( flags & SQLITE_SHM_SHARED ){
+        /* Case (b) - a shared lock.  */
+
+        if( aLock[ofst]<0 ){
+          /* An exclusive lock is held by some other connection. BUSY. */
+          rc = SQLITE_BUSY;
+        }else if( aLock[ofst]==0 ){
+          rc = unixShmSystemLock(pDbFd, F_RDLCK, ofst+UNIX_SHM_BASE, n);
+        }
+
+        /* Get the local shared locks */
+        if( rc==SQLITE_OK ){
+          p->sharedMask |= mask;
+          aLock[ofst]++;
+        }
+      }else{
+        /* Case (c) - an exclusive lock.  */
+        int ii;
+
+        assert( flags==(SQLITE_SHM_LOCK|SQLITE_SHM_EXCLUSIVE) );
+        assert( (p->sharedMask & mask)==0 );
+        assert( (p->exclMask & mask)==0 );
+
+        /* Make sure no sibling connections hold locks that will block this
+        ** lock.  If any do, return SQLITE_BUSY right away.  */
+        for(ii=ofst; ii<ofst+n; ii++){
+          if( aLock[ii] ){
+            rc = SQLITE_BUSY;
+            break;
+          }
+        }
+
+        /* Get the exclusive locks at the system level. Then if successful
+        ** also update the in-memory values. */
+        if( rc==SQLITE_OK ){
+          rc = unixShmSystemLock(pDbFd, F_WRLCK, ofst+UNIX_SHM_BASE, n);
+          if( rc==SQLITE_OK ){
+            p->exclMask |= mask;
+            for(ii=ofst; ii<ofst+n; ii++){
+              aLock[ii] = -1;
+            }
+          }
+        }
+      }
+      assert( assertLockingArrayOk(pShmNode) );
+    }
+
+    /* Drop the mutexes acquired above. */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  leave_shmnode_mutexes:
+    for(iMutex--; iMutex>=ofst; iMutex--){
+      sqlite3_mutex_leave(pShmNode->aMutex[iMutex]);
+    }
+#else
+    sqlite3_mutex_leave(pShmNode->pShmMutex);
+#endif
+  }
+
+  OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x\n",
+           p->id, osGetpid(0), p->sharedMask, p->exclMask));
+  return rc;
+}
+
+/*
+** Implement a memory barrier or memory fence on shared memory.
+**
+** All loads and stores begun before the barrier must complete before
+** any load or store begun after the barrier.
+*/
+static void unixShmBarrier(
+  sqlite3_file *fd                /* Database file holding the shared memory */
+){
+  UNUSED_PARAMETER(fd);
+  sqlite3MemoryBarrier();         /* compiler-defined memory barrier */
+  assert( fd->pMethods->xLock==nolockLock
+       || unixFileMutexNotheld((unixFile*)fd)
+  );
+  unixEnterMutex();               /* Also mutex, for redundancy */
+  unixLeaveMutex();
+}
+
+/*
+** Close a connection to shared-memory.  Delete the underlying
+** storage if deleteFlag is true.
+**
+** If there is no shared memory associated with the connection then this
+** routine is a harmless no-op.
+*/
+static int unixShmUnmap(
+  sqlite3_file *fd,               /* The underlying database file */
+  int deleteFlag                  /* Delete shared-memory if true */
+){
+  unixShm *p;                     /* The connection to be closed */
+  unixShmNode *pShmNode;          /* The underlying shared-memory file */
+  unixShm **pp;                   /* For looping over sibling connections */
+  unixFile *pDbFd;                /* The underlying database file */
+
+  pDbFd = (unixFile*)fd;
+  p = pDbFd->pShm;
+  if( p==0 ) return SQLITE_OK;
+  pShmNode = p->pShmNode;
+
+  assert( pShmNode==pDbFd->pInode->pShmNode );
+  assert( pShmNode->pInode==pDbFd->pInode );
+
+  /* Remove connection p from the set of connections associated
+  ** with pShmNode */
+  sqlite3_mutex_enter(pShmNode->pShmMutex);
+  for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
+  *pp = p->pNext;
+
+  /* Free the connection p */
+  sqlite3_free(p);
+  pDbFd->pShm = 0;
+  sqlite3_mutex_leave(pShmNode->pShmMutex);
+
+  /* If pShmNode->nRef has reached 0, then close the underlying
+  ** shared-memory file, too */
+  assert( unixFileMutexNotheld(pDbFd) );
+  unixEnterMutex();
+  assert( pShmNode->nRef>0 );
+  pShmNode->nRef--;
+  if( pShmNode->nRef==0 ){
+    if( deleteFlag && pShmNode->hShm>=0 ){
+      osUnlink(pShmNode->zFilename);
+    }
+    unixShmPurge(pDbFd);
+  }
+  unixLeaveMutex();
+
+  return SQLITE_OK;
+}
+
+
+#else
+# define unixShmMap     0
+# define unixShmLock    0
+# define unixShmBarrier 0
+# define unixShmUnmap   0
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/*
+** If it is currently memory mapped, unmap file pFd.
+*/
+static void unixUnmapfile(unixFile *pFd){
+  assert( pFd->nFetchOut==0 );
+  if( pFd->pMapRegion ){
+    osMunmap(pFd->pMapRegion, pFd->mmapSizeActual);
+    pFd->pMapRegion = 0;
+    pFd->mmapSize = 0;
+    pFd->mmapSizeActual = 0;
+  }
+}
+
+/*
+** Attempt to set the size of the memory mapping maintained by file
+** descriptor pFd to nNew bytes. Any existing mapping is discarded.
+**
+** If successful, this function sets the following variables:
+**
+**       unixFile.pMapRegion
+**       unixFile.mmapSize
+**       unixFile.mmapSizeActual
+**
+** If unsuccessful, an error message is logged via sqlite3_log() and
+** the three variables above are zeroed. In this case SQLite should
+** continue accessing the database using the xRead() and xWrite()
+** methods.
+*/
+static void unixRemapfile(
+  unixFile *pFd,                  /* File descriptor object */
+  i64 nNew                        /* Required mapping size */
+){
+  const char *zErr = "mmap";
+  int h = pFd->h;                      /* File descriptor open on db file */
+  u8 *pOrig = (u8 *)pFd->pMapRegion;   /* Pointer to current file mapping */
+  i64 nOrig = pFd->mmapSizeActual;     /* Size of pOrig region in bytes */
+  u8 *pNew = 0;                        /* Location of new mapping */
+  int flags = PROT_READ;               /* Flags to pass to mmap() */
+
+  assert( pFd->nFetchOut==0 );
+  assert( nNew>pFd->mmapSize );
+  assert( nNew<=pFd->mmapSizeMax );
+  assert( nNew>0 );
+  assert( pFd->mmapSizeActual>=pFd->mmapSize );
+  assert( MAP_FAILED!=0 );
+
+#ifdef SQLITE_MMAP_READWRITE
+  if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE;
+#endif
+
+  if( pOrig ){
+#if HAVE_MREMAP
+    i64 nReuse = pFd->mmapSize;
+#else
+    const int szSyspage = osGetpagesize();
+    i64 nReuse = (pFd->mmapSize & ~(szSyspage-1));
+#endif
+    u8 *pReq = &pOrig[nReuse];
+
+    /* Unmap any pages of the existing mapping that cannot be reused. */
+    if( nReuse!=nOrig ){
+      osMunmap(pReq, nOrig-nReuse);
+    }
+
+#if HAVE_MREMAP
+    pNew = osMremap(pOrig, nReuse, nNew, MREMAP_MAYMOVE);
+    zErr = "mremap";
+#else
+    pNew = osMmap(pReq, nNew-nReuse, flags, MAP_SHARED, h, nReuse);
+    if( pNew!=MAP_FAILED ){
+      if( pNew!=pReq ){
+        osMunmap(pNew, nNew - nReuse);
+        pNew = 0;
+      }else{
+        pNew = pOrig;
+      }
+    }
+#endif
+
+    /* The attempt to extend the existing mapping failed. Free it. */
+    if( pNew==MAP_FAILED || pNew==0 ){
+      osMunmap(pOrig, nReuse);
+    }
+  }
+
+  /* If pNew is still NULL, try to create an entirely new mapping. */
+  if( pNew==0 ){
+    pNew = osMmap(0, nNew, flags, MAP_SHARED, h, 0);
+  }
+
+  if( pNew==MAP_FAILED ){
+    pNew = 0;
+    nNew = 0;
+    unixLogError(SQLITE_OK, zErr, pFd->zPath);
+
+    /* If the mmap() above failed, assume that all subsequent mmap() calls
+    ** will probably fail too. Fall back to using xRead/xWrite exclusively
+    ** in this case.  */
+    pFd->mmapSizeMax = 0;
+  }
+  pFd->pMapRegion = (void *)pNew;
+  pFd->mmapSize = pFd->mmapSizeActual = nNew;
+}
+
+/*
+** Memory map or remap the file opened by file-descriptor pFd (if the file
+** is already mapped, the existing mapping is replaced by the new). Or, if
+** there already exists a mapping for this file, and there are still
+** outstanding xFetch() references to it, this function is a no-op.
+**
+** If parameter nByte is non-negative, then it is the requested size of
+** the mapping to create. Otherwise, if nByte is less than zero, then the
+** requested size is the size of the file on disk. The actual size of the
+** created mapping is either the requested size or the value configured
+** using SQLITE_FCNTL_MMAP_LIMIT, whichever is smaller.
+**
+** SQLITE_OK is returned if no error occurs (even if the mapping is not
+** recreated as a result of outstanding references) or an SQLite error
+** code otherwise.
+*/
+static int unixMapfile(unixFile *pFd, i64 nMap){
+  assert( nMap>=0 || pFd->nFetchOut==0 );
+  assert( nMap>0 || (pFd->mmapSize==0 && pFd->pMapRegion==0) );
+  if( pFd->nFetchOut>0 ) return SQLITE_OK;
+
+  if( nMap<0 ){
+    struct stat statbuf;          /* Low-level file information */
+    if( osFstat(pFd->h, &statbuf) ){
+      return SQLITE_IOERR_FSTAT;
+    }
+    nMap = statbuf.st_size;
+  }
+  if( nMap>pFd->mmapSizeMax ){
+    nMap = pFd->mmapSizeMax;
+  }
+
+  assert( nMap>0 || (pFd->mmapSize==0 && pFd->pMapRegion==0) );
+  if( nMap!=pFd->mmapSize ){
+    unixRemapfile(pFd, nMap);
+  }
+
+  return SQLITE_OK;
+}
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+
+/*
+** If possible, return a pointer to a mapping of file fd starting at offset
+** iOff. The mapping must be valid for at least nAmt bytes.
+**
+** If such a pointer can be obtained, store it in *pp and return SQLITE_OK.
+** Or, if one cannot but no error occurs, set *pp to 0 and return SQLITE_OK.
+** Finally, if an error does occur, return an SQLite error code. The final
+** value of *pp is undefined in this case.
+**
+** If this function does return a pointer, the caller must eventually
+** release the reference by calling unixUnfetch().
+*/
+static int unixFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){
+#if SQLITE_MAX_MMAP_SIZE>0
+  unixFile *pFd = (unixFile *)fd;   /* The underlying database file */
+#endif
+  *pp = 0;
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFd->mmapSizeMax>0 ){
+    /* Ensure that there is always at least a 256 byte buffer of addressable
+    ** memory following the returned page. If the database is corrupt,
+    ** SQLite may overread the page slightly (in practice only a few bytes,
+    ** but 256 is safe, round, number).  */
+    const int nEofBuffer = 256;
+    if( pFd->pMapRegion==0 ){
+      int rc = unixMapfile(pFd, -1);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    if( pFd->mmapSize >= (iOff+nAmt+nEofBuffer) ){
+      *pp = &((u8 *)pFd->pMapRegion)[iOff];
+      pFd->nFetchOut++;
+    }
+  }
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** If the third argument is non-NULL, then this function releases a
+** reference obtained by an earlier call to unixFetch(). The second
+** argument passed to this function must be the same as the corresponding
+** argument that was passed to the unixFetch() invocation.
+**
+** Or, if the third argument is NULL, then this function is being called
+** to inform the VFS layer that, according to POSIX, any existing mapping
+** may now be invalid and should be unmapped.
+*/
+static int unixUnfetch(sqlite3_file *fd, i64 iOff, void *p){
+#if SQLITE_MAX_MMAP_SIZE>0
+  unixFile *pFd = (unixFile *)fd;   /* The underlying database file */
+  UNUSED_PARAMETER(iOff);
+
+  /* If p==0 (unmap the entire file) then there must be no outstanding
+  ** xFetch references. Or, if p!=0 (meaning it is an xFetch reference),
+  ** then there must be at least one outstanding.  */
+  assert( (p==0)==(pFd->nFetchOut==0) );
+
+  /* If p!=0, it must match the iOff value. */
+  assert( p==0 || p==&((u8 *)pFd->pMapRegion)[iOff] );
+
+  if( p ){
+    pFd->nFetchOut--;
+  }else{
+    unixUnmapfile(pFd);
+  }
+
+  assert( pFd->nFetchOut>=0 );
+#else
+  UNUSED_PARAMETER(fd);
+  UNUSED_PARAMETER(p);
+  UNUSED_PARAMETER(iOff);
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Here ends the implementation of all sqlite3_file methods.
+**
+********************** End sqlite3_file Methods *******************************
+******************************************************************************/
+
+/*
+** This division contains definitions of sqlite3_io_methods objects that
+** implement various file locking strategies.  It also contains definitions
+** of "finder" functions.  A finder-function is used to locate the appropriate
+** sqlite3_io_methods object for a particular database file.  The pAppData
+** field of the sqlite3_vfs VFS objects are initialized to be pointers to
+** the correct finder-function for that VFS.
+**
+** Most finder functions return a pointer to a fixed sqlite3_io_methods
+** object.  The only interesting finder-function is autolockIoFinder, which
+** looks at the filesystem type and tries to guess the best locking
+** strategy from that.
+**
+** For finder-function F, two objects are created:
+**
+**    (1) The real finder-function named "FImpt()".
+**
+**    (2) A constant pointer to this function named just "F".
+**
+**
+** A pointer to the F pointer is used as the pAppData value for VFS
+** objects.  We have to do this instead of letting pAppData point
+** directly at the finder-function since C90 rules prevent a void*
+** from be cast into a function pointer.
+**
+**
+** Each instance of this macro generates two objects:
+**
+**   *  A constant sqlite3_io_methods object call METHOD that has locking
+**      methods CLOSE, LOCK, UNLOCK, CKRESLOCK.
+**
+**   *  An I/O method finder function called FINDER that returns a pointer
+**      to the METHOD object in the previous bullet.
+*/
+#define IOMETHODS(FINDER,METHOD,VERSION,CLOSE,LOCK,UNLOCK,CKLOCK,SHMMAP)     \
+static const sqlite3_io_methods METHOD = {                                   \
+   VERSION,                    /* iVersion */                                \
+   CLOSE,                      /* xClose */                                  \
+   unixRead,                   /* xRead */                                   \
+   unixWrite,                  /* xWrite */                                  \
+   unixTruncate,               /* xTruncate */                               \
+   unixSync,                   /* xSync */                                   \
+   unixFileSize,               /* xFileSize */                               \
+   LOCK,                       /* xLock */                                   \
+   UNLOCK,                     /* xUnlock */                                 \
+   CKLOCK,                     /* xCheckReservedLock */                      \
+   unixFileControl,            /* xFileControl */                            \
+   unixSectorSize,             /* xSectorSize */                             \
+   unixDeviceCharacteristics,  /* xDeviceCapabilities */                     \
+   SHMMAP,                     /* xShmMap */                                 \
+   unixShmLock,                /* xShmLock */                                \
+   unixShmBarrier,             /* xShmBarrier */                             \
+   unixShmUnmap,               /* xShmUnmap */                               \
+   unixFetch,                  /* xFetch */                                  \
+   unixUnfetch,                /* xUnfetch */                                \
+};                                                                           \
+static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){   \
+  UNUSED_PARAMETER(z); UNUSED_PARAMETER(p);                                  \
+  return &METHOD;                                                            \
+}                                                                            \
+static const sqlite3_io_methods *(*const FINDER)(const char*,unixFile *p)    \
+    = FINDER##Impl;
+
+/*
+** Here are all of the sqlite3_io_methods objects for each of the
+** locking strategies.  Functions that return pointers to these methods
+** are also created.
+*/
+IOMETHODS(
+  posixIoFinder,            /* Finder function name */
+  posixIoMethods,           /* sqlite3_io_methods object name */
+  3,                        /* shared memory and mmap are enabled */
+  unixClose,                /* xClose method */
+  unixLock,                 /* xLock method */
+  unixUnlock,               /* xUnlock method */
+  unixCheckReservedLock,    /* xCheckReservedLock method */
+  unixShmMap                /* xShmMap method */
+)
+IOMETHODS(
+  nolockIoFinder,           /* Finder function name */
+  nolockIoMethods,          /* sqlite3_io_methods object name */
+  3,                        /* shared memory and mmap are enabled */
+  nolockClose,              /* xClose method */
+  nolockLock,               /* xLock method */
+  nolockUnlock,             /* xUnlock method */
+  nolockCheckReservedLock,  /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+IOMETHODS(
+  dotlockIoFinder,          /* Finder function name */
+  dotlockIoMethods,         /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  dotlockClose,             /* xClose method */
+  dotlockLock,              /* xLock method */
+  dotlockUnlock,            /* xUnlock method */
+  dotlockCheckReservedLock, /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+
+#if SQLITE_ENABLE_LOCKING_STYLE
+IOMETHODS(
+  flockIoFinder,            /* Finder function name */
+  flockIoMethods,           /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  flockClose,               /* xClose method */
+  flockLock,                /* xLock method */
+  flockUnlock,              /* xUnlock method */
+  flockCheckReservedLock,   /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+#endif
+
+#if OS_VXWORKS
+IOMETHODS(
+  semIoFinder,              /* Finder function name */
+  semIoMethods,             /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  semXClose,                /* xClose method */
+  semXLock,                 /* xLock method */
+  semXUnlock,               /* xUnlock method */
+  semXCheckReservedLock,    /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+#endif
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+IOMETHODS(
+  afpIoFinder,              /* Finder function name */
+  afpIoMethods,             /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  afpClose,                 /* xClose method */
+  afpLock,                  /* xLock method */
+  afpUnlock,                /* xUnlock method */
+  afpCheckReservedLock,     /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+#endif
+
+/*
+** The proxy locking method is a "super-method" in the sense that it
+** opens secondary file descriptors for the conch and lock files and
+** it uses proxy, dot-file, AFP, and flock() locking methods on those
+** secondary files.  For this reason, the division that implements
+** proxy locking is located much further down in the file.  But we need
+** to go ahead and define the sqlite3_io_methods and finder function
+** for proxy locking here.  So we forward declare the I/O methods.
+*/
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+static int proxyClose(sqlite3_file*);
+static int proxyLock(sqlite3_file*, int);
+static int proxyUnlock(sqlite3_file*, int);
+static int proxyCheckReservedLock(sqlite3_file*, int*);
+IOMETHODS(
+  proxyIoFinder,            /* Finder function name */
+  proxyIoMethods,           /* sqlite3_io_methods object name */
+  1,                        /* shared memory is disabled */
+  proxyClose,               /* xClose method */
+  proxyLock,                /* xLock method */
+  proxyUnlock,              /* xUnlock method */
+  proxyCheckReservedLock,   /* xCheckReservedLock method */
+  0                         /* xShmMap method */
+)
+#endif
+
+/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+IOMETHODS(
+  nfsIoFinder,               /* Finder function name */
+  nfsIoMethods,              /* sqlite3_io_methods object name */
+  1,                         /* shared memory is disabled */
+  unixClose,                 /* xClose method */
+  unixLock,                  /* xLock method */
+  nfsUnlock,                 /* xUnlock method */
+  unixCheckReservedLock,     /* xCheckReservedLock method */
+  0                          /* xShmMap method */
+)
+#endif
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+/*
+** This "finder" function attempts to determine the best locking strategy
+** for the database file "filePath".  It then returns the sqlite3_io_methods
+** object that implements that strategy.
+**
+** This is for MacOSX only.
+*/
+static const sqlite3_io_methods *autolockIoFinderImpl(
+  const char *filePath,    /* name of the database file */
+  unixFile *pNew           /* open file object for the database file */
+){
+  static const struct Mapping {
+    const char *zFilesystem;              /* Filesystem type name */
+    const sqlite3_io_methods *pMethods;   /* Appropriate locking method */
+  } aMap[] = {
+    { "hfs",    &posixIoMethods },
+    { "ufs",    &posixIoMethods },
+    { "afpfs",  &afpIoMethods },
+    { "smbfs",  &afpIoMethods },
+    { "webdav", &nolockIoMethods },
+    { 0, 0 }
+  };
+  int i;
+  struct statfs fsInfo;
+  struct flock lockInfo;
+
+  if( !filePath ){
+    /* If filePath==NULL that means we are dealing with a transient file
+    ** that does not need to be locked. */
+    return &nolockIoMethods;
+  }
+  if( statfs(filePath, &fsInfo) != -1 ){
+    if( fsInfo.f_flags & MNT_RDONLY ){
+      return &nolockIoMethods;
+    }
+    for(i=0; aMap[i].zFilesystem; i++){
+      if( strcmp(fsInfo.f_fstypename, aMap[i].zFilesystem)==0 ){
+        return aMap[i].pMethods;
+      }
+    }
+  }
+
+  /* Default case. Handles, amongst others, "nfs".
+  ** Test byte-range lock using fcntl(). If the call succeeds,
+  ** assume that the file-system supports POSIX style locks.
+  */
+  lockInfo.l_len = 1;
+  lockInfo.l_start = 0;
+  lockInfo.l_whence = SEEK_SET;
+  lockInfo.l_type = F_RDLCK;
+  if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
+    if( strcmp(fsInfo.f_fstypename, "nfs")==0 ){
+      return &nfsIoMethods;
+    } else {
+      return &posixIoMethods;
+    }
+  }else{
+    return &dotlockIoMethods;
+  }
+}
+static const sqlite3_io_methods
+  *(*const autolockIoFinder)(const char*,unixFile*) = autolockIoFinderImpl;
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+
+#if OS_VXWORKS
+/*
+** This "finder" function for VxWorks checks to see if posix advisory
+** locking works.  If it does, then that is what is used.  If it does not
+** work, then fallback to named semaphore locking.
+*/
+static const sqlite3_io_methods *vxworksIoFinderImpl(
+  const char *filePath,    /* name of the database file */
+  unixFile *pNew           /* the open file object */
+){
+  struct flock lockInfo;
+
+  if( !filePath ){
+    /* If filePath==NULL that means we are dealing with a transient file
+    ** that does not need to be locked. */
+    return &nolockIoMethods;
+  }
+
+  /* Test if fcntl() is supported and use POSIX style locks.
+  ** Otherwise fall back to the named semaphore method.
+  */
+  lockInfo.l_len = 1;
+  lockInfo.l_start = 0;
+  lockInfo.l_whence = SEEK_SET;
+  lockInfo.l_type = F_RDLCK;
+  if( osFcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
+    return &posixIoMethods;
+  }else{
+    return &semIoMethods;
+  }
+}
+static const sqlite3_io_methods
+  *(*const vxworksIoFinder)(const char*,unixFile*) = vxworksIoFinderImpl;
+
+#endif /* OS_VXWORKS */
+
+/*
+** An abstract type for a pointer to an IO method finder function:
+*/
+typedef const sqlite3_io_methods *(*finder_type)(const char*,unixFile*);
+
+
+/****************************************************************************
+**************************** sqlite3_vfs methods ****************************
+**
+** This division contains the implementation of methods on the
+** sqlite3_vfs object.
+*/
+
+/*
+** Initialize the contents of the unixFile structure pointed to by pId.
+*/
+static int fillInUnixFile(
+  sqlite3_vfs *pVfs,      /* Pointer to vfs object */
+  int h,                  /* Open file descriptor of file being opened */
+  sqlite3_file *pId,      /* Write to the unixFile structure here */
+  const char *zFilename,  /* Name of the file being opened */
+  int ctrlFlags           /* Zero or more UNIXFILE_* values */
+){
+  const sqlite3_io_methods *pLockingStyle;
+  unixFile *pNew = (unixFile *)pId;
+  int rc = SQLITE_OK;
+
+  assert( pNew->pInode==NULL );
+
+  /* No locking occurs in temporary files */
+  assert( zFilename!=0 || (ctrlFlags & UNIXFILE_NOLOCK)!=0 );
+
+  OSTRACE(("OPEN    %-3d %s\n", h, zFilename));
+  pNew->h = h;
+  pNew->pVfs = pVfs;
+  pNew->zPath = zFilename;
+  pNew->ctrlFlags = (u8)ctrlFlags;
+#if SQLITE_MAX_MMAP_SIZE>0
+  pNew->mmapSizeMax = sqlite3GlobalConfig.szMmap;
+#endif
+  if( sqlite3_uri_boolean(((ctrlFlags & UNIXFILE_URI) ? zFilename : 0),
+                           "psow", SQLITE_POWERSAFE_OVERWRITE) ){
+    pNew->ctrlFlags |= UNIXFILE_PSOW;
+  }
+  if( strcmp(pVfs->zName,"unix-excl")==0 ){
+    pNew->ctrlFlags |= UNIXFILE_EXCL;
+  }
+
+#if OS_VXWORKS
+  pNew->pId = vxworksFindFileId(zFilename);
+  if( pNew->pId==0 ){
+    ctrlFlags |= UNIXFILE_NOLOCK;
+    rc = SQLITE_NOMEM_BKPT;
+  }
+#endif
+
+  if( ctrlFlags & UNIXFILE_NOLOCK ){
+    pLockingStyle = &nolockIoMethods;
+  }else{
+    pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew);
+#if SQLITE_ENABLE_LOCKING_STYLE
+    /* Cache zFilename in the locking context (AFP and dotlock override) for
+    ** proxyLock activation is possible (remote proxy is based on db name)
+    ** zFilename remains valid until file is closed, to support */
+    pNew->lockingContext = (void*)zFilename;
+#endif
+  }
+
+  if( pLockingStyle == &posixIoMethods
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+    || pLockingStyle == &nfsIoMethods
+#endif
+  ){
+    unixEnterMutex();
+    rc = findInodeInfo(pNew, &pNew->pInode);
+    if( rc!=SQLITE_OK ){
+      /* If an error occurred in findInodeInfo(), close the file descriptor
+      ** immediately, before releasing the mutex. findInodeInfo() may fail
+      ** in two scenarios:
+      **
+      **   (a) A call to fstat() failed.
+      **   (b) A malloc failed.
+      **
+      ** Scenario (b) may only occur if the process is holding no other
+      ** file descriptors open on the same file. If there were other file
+      ** descriptors on this file, then no malloc would be required by
+      ** findInodeInfo(). If this is the case, it is quite safe to close
+      ** handle h - as it is guaranteed that no posix locks will be released
+      ** by doing so.
+      **
+      ** If scenario (a) caused the error then things are not so safe. The
+      ** implicit assumption here is that if fstat() fails, things are in
+      ** such bad shape that dropping a lock or two doesn't matter much.
+      */
+      robust_close(pNew, h, __LINE__);
+      h = -1;
+    }
+    unixLeaveMutex();
+  }
+
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+  else if( pLockingStyle == &afpIoMethods ){
+    /* AFP locking uses the file path so it needs to be included in
+    ** the afpLockingContext.
+    */
+    afpLockingContext *pCtx;
+    pNew->lockingContext = pCtx = sqlite3_malloc64( sizeof(*pCtx) );
+    if( pCtx==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      /* NB: zFilename exists and remains valid until the file is closed
+      ** according to requirement F11141.  So we do not need to make a
+      ** copy of the filename. */
+      pCtx->dbPath = zFilename;
+      pCtx->reserved = 0;
+      srandomdev();
+      unixEnterMutex();
+      rc = findInodeInfo(pNew, &pNew->pInode);
+      if( rc!=SQLITE_OK ){
+        sqlite3_free(pNew->lockingContext);
+        robust_close(pNew, h, __LINE__);
+        h = -1;
+      }
+      unixLeaveMutex();
+    }
+  }
+#endif
+
+  else if( pLockingStyle == &dotlockIoMethods ){
+    /* Dotfile locking uses the file path so it needs to be included in
+    ** the dotlockLockingContext
+    */
+    char *zLockFile;
+    int nFilename;
+    assert( zFilename!=0 );
+    nFilename = (int)strlen(zFilename) + 6;
+    zLockFile = (char *)sqlite3_malloc64(nFilename);
+    if( zLockFile==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      sqlite3_snprintf(nFilename, zLockFile, "%s" DOTLOCK_SUFFIX, zFilename);
+    }
+    pNew->lockingContext = zLockFile;
+  }
+
+#if OS_VXWORKS
+  else if( pLockingStyle == &semIoMethods ){
+    /* Named semaphore locking uses the file path so it needs to be
+    ** included in the semLockingContext
+    */
+    unixEnterMutex();
+    rc = findInodeInfo(pNew, &pNew->pInode);
+    if( (rc==SQLITE_OK) && (pNew->pInode->pSem==NULL) ){
+      char *zSemName = pNew->pInode->aSemName;
+      int n;
+      sqlite3_snprintf(MAX_PATHNAME, zSemName, "/%s.sem",
+                       pNew->pId->zCanonicalName);
+      for( n=1; zSemName[n]; n++ )
+        if( zSemName[n]=='/' ) zSemName[n] = '_';
+      pNew->pInode->pSem = sem_open(zSemName, O_CREAT, 0666, 1);
+      if( pNew->pInode->pSem == SEM_FAILED ){
+        rc = SQLITE_NOMEM_BKPT;
+        pNew->pInode->aSemName[0] = '\0';
+      }
+    }
+    unixLeaveMutex();
+  }
+#endif
+
+  storeLastErrno(pNew, 0);
+#if OS_VXWORKS
+  if( rc!=SQLITE_OK ){
+    if( h>=0 ) robust_close(pNew, h, __LINE__);
+    h = -1;
+    osUnlink(zFilename);
+    pNew->ctrlFlags |= UNIXFILE_DELETE;
+  }
+#endif
+  if( rc!=SQLITE_OK ){
+    if( h>=0 ) robust_close(pNew, h, __LINE__);
+  }else{
+    pId->pMethods = pLockingStyle;
+    OpenCounter(+1);
+    verifyDbFile(pNew);
+  }
+  return rc;
+}
+
+/*
+** Directories to consider for temp files.
+*/
+static const char *azTempDirs[] = {
+  0,
+  0,
+  "/var/tmp",
+  "/usr/tmp",
+  "/tmp",
+  "."
+};
+
+/*
+** Initialize first two members of azTempDirs[] array.
+*/
+static void unixTempFileInit(void){
+  azTempDirs[0] = getenv("SQLITE_TMPDIR");
+  azTempDirs[1] = getenv("TMPDIR");
+}
+
+/*
+** Return the name of a directory in which to put temporary files.
+** If no suitable temporary file directory can be found, return NULL.
+*/
+static const char *unixTempFileDir(void){
+  unsigned int i = 0;
+  struct stat buf;
+  const char *zDir = sqlite3_temp_directory;
+
+  while(1){
+    if( zDir!=0
+     && osStat(zDir, &buf)==0
+     && S_ISDIR(buf.st_mode)
+     && osAccess(zDir, 03)==0
+    ){
+      return zDir;
+    }
+    if( i>=sizeof(azTempDirs)/sizeof(azTempDirs[0]) ) break;
+    zDir = azTempDirs[i++];
+  }
+  return 0;
+}
+
+/*
+** Create a temporary file name in zBuf.  zBuf must be allocated
+** by the calling process and must be big enough to hold at least
+** pVfs->mxPathname bytes.
+*/
+static int unixGetTempname(int nBuf, char *zBuf){
+  const char *zDir;
+  int iLimit = 0;
+  int rc = SQLITE_OK;
+
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing.
+  */
+  zBuf[0] = 0;
+  SimulateIOError( return SQLITE_IOERR );
+
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  zDir = unixTempFileDir();
+  if( zDir==0 ){
+    rc = SQLITE_IOERR_GETTEMPPATH;
+  }else{
+    do{
+      u64 r;
+      sqlite3_randomness(sizeof(r), &r);
+      assert( nBuf>2 );
+      zBuf[nBuf-2] = 0;
+      sqlite3_snprintf(nBuf, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX"%llx%c",
+                       zDir, r, 0);
+      if( zBuf[nBuf-2]!=0 || (iLimit++)>10 ){
+        rc = SQLITE_ERROR;
+        break;
+      }
+    }while( osAccess(zBuf,0)==0 );
+  }
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return rc;
+}
+
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+/*
+** Routine to transform a unixFile into a proxy-locking unixFile.
+** Implementation in the proxy-lock division, but used by unixOpen()
+** if SQLITE_PREFER_PROXY_LOCKING is defined.
+*/
+static int proxyTransformUnixFile(unixFile*, const char*);
+#endif
+
+/*
+** Search for an unused file descriptor that was opened on the database
+** file (not a journal or super-journal file) identified by pathname
+** zPath with SQLITE_OPEN_XXX flags matching those passed as the second
+** argument to this function.
+**
+** Such a file descriptor may exist if a database connection was closed
+** but the associated file descriptor could not be closed because some
+** other file descriptor open on the same file is holding a file-lock.
+** Refer to comments in the unixClose() function and the lengthy comment
+** describing "Posix Advisory Locking" at the start of this file for
+** further details. Also, ticket #4018.
+**
+** If a suitable file descriptor is found, then it is returned. If no
+** such file descriptor is located, -1 is returned.
+*/
+static UnixUnusedFd *findReusableFd(const char *zPath, int flags){
+  UnixUnusedFd *pUnused = 0;
+
+  /* Do not search for an unused file descriptor on vxworks. Not because
+  ** vxworks would not benefit from the change (it might, we're not sure),
+  ** but because no way to test it is currently available. It is better
+  ** not to risk breaking vxworks support for the sake of such an obscure
+  ** feature.  */
+#if !OS_VXWORKS
+  struct stat sStat;                   /* Results of stat() call */
+
+  unixEnterMutex();
+
+  /* A stat() call may fail for various reasons. If this happens, it is
+  ** almost certain that an open() call on the same path will also fail.
+  ** For this reason, if an error occurs in the stat() call here, it is
+  ** ignored and -1 is returned. The caller will try to open a new file
+  ** descriptor on the same path, fail, and return an error to SQLite.
+  **
+  ** Even if a subsequent open() call does succeed, the consequences of
+  ** not searching for a reusable file descriptor are not dire.  */
+  if( inodeList!=0 && 0==osStat(zPath, &sStat) ){
+    unixInodeInfo *pInode;
+
+    pInode = inodeList;
+    while( pInode && (pInode->fileId.dev!=sStat.st_dev
+                     || pInode->fileId.ino!=(u64)sStat.st_ino) ){
+       pInode = pInode->pNext;
+    }
+    if( pInode ){
+      UnixUnusedFd **pp;
+      assert( sqlite3_mutex_notheld(pInode->pLockMutex) );
+      sqlite3_mutex_enter(pInode->pLockMutex);
+      flags &= (SQLITE_OPEN_READONLY|SQLITE_OPEN_READWRITE);
+      for(pp=&pInode->pUnused; *pp && (*pp)->flags!=flags; pp=&((*pp)->pNext));
+      pUnused = *pp;
+      if( pUnused ){
+        *pp = pUnused->pNext;
+      }
+      sqlite3_mutex_leave(pInode->pLockMutex);
+    }
+  }
+  unixLeaveMutex();
+#endif    /* if !OS_VXWORKS */
+  return pUnused;
+}
+
+/*
+** Find the mode, uid and gid of file zFile.
+*/
+static int getFileMode(
+  const char *zFile,              /* File name */
+  mode_t *pMode,                  /* OUT: Permissions of zFile */
+  uid_t *pUid,                    /* OUT: uid of zFile. */
+  gid_t *pGid                     /* OUT: gid of zFile. */
+){
+  struct stat sStat;              /* Output of stat() on database file */
+  int rc = SQLITE_OK;
+  if( 0==osStat(zFile, &sStat) ){
+    *pMode = sStat.st_mode & 0777;
+    *pUid = sStat.st_uid;
+    *pGid = sStat.st_gid;
+  }else{
+    rc = SQLITE_IOERR_FSTAT;
+  }
+  return rc;
+}
+
+/*
+** This function is called by unixOpen() to determine the unix permissions
+** to create new files with. If no error occurs, then SQLITE_OK is returned
+** and a value suitable for passing as the third argument to open(2) is
+** written to *pMode. If an IO error occurs, an SQLite error code is
+** returned and the value of *pMode is not modified.
+**
+** In most cases, this routine sets *pMode to 0, which will become
+** an indication to robust_open() to create the file using
+** SQLITE_DEFAULT_FILE_PERMISSIONS adjusted by the umask.
+** But if the file being opened is a WAL or regular journal file, then
+** this function queries the file-system for the permissions on the
+** corresponding database file and sets *pMode to this value. Whenever
+** possible, WAL and journal files are created using the same permissions
+** as the associated database file.
+**
+** If the SQLITE_ENABLE_8_3_NAMES option is enabled, then the
+** original filename is unavailable.  But 8_3_NAMES is only used for
+** FAT filesystems and permissions do not matter there, so just use
+** the default permissions.  In 8_3_NAMES mode, leave *pMode set to zero.
+*/
+static int findCreateFileMode(
+  const char *zPath,              /* Path of file (possibly) being created */
+  int flags,                      /* Flags passed as 4th argument to xOpen() */
+  mode_t *pMode,                  /* OUT: Permissions to open file with */
+  uid_t *pUid,                    /* OUT: uid to set on the file */
+  gid_t *pGid                     /* OUT: gid to set on the file */
+){
+  int rc = SQLITE_OK;             /* Return Code */
+  *pMode = 0;
+  *pUid = 0;
+  *pGid = 0;
+  if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){
+    char zDb[MAX_PATHNAME+1];     /* Database file path */
+    int nDb;                      /* Number of valid bytes in zDb */
+
+    /* zPath is a path to a WAL or journal file. The following block derives
+    ** the path to the associated database file from zPath. This block handles
+    ** the following naming conventions:
+    **
+    **   "<path to db>-journal"
+    **   "<path to db>-wal"
+    **   "<path to db>-journalNN"
+    **   "<path to db>-walNN"
+    **
+    ** where NN is a decimal number. The NN naming schemes are
+    ** used by the test_multiplex.c module.
+    **
+    ** In normal operation, the journal file name will always contain
+    ** a '-' character.  However in 8+3 filename mode, or if a corrupt
+    ** rollback journal specifies a super-journal with a goofy name, then
+    ** the '-' might be missing or the '-' might be the first character in
+    ** the filename.  In that case, just return SQLITE_OK with *pMode==0.
+    */
+    nDb = sqlite3Strlen30(zPath) - 1;
+    while( nDb>0 && zPath[nDb]!='.' ){
+      if( zPath[nDb]=='-' ){
+        memcpy(zDb, zPath, nDb);
+        zDb[nDb] = '\0';
+        rc = getFileMode(zDb, pMode, pUid, pGid);
+        break;
+      }
+      nDb--;
+    }
+  }else if( flags & SQLITE_OPEN_DELETEONCLOSE ){
+    *pMode = 0600;
+  }else if( flags & SQLITE_OPEN_URI ){
+    /* If this is a main database file and the file was opened using a URI
+    ** filename, check for the "modeof" parameter. If present, interpret
+    ** its value as a filename and try to copy the mode, uid and gid from
+    ** that file.  */
+    const char *z = sqlite3_uri_parameter(zPath, "modeof");
+    if( z ){
+      rc = getFileMode(z, pMode, pUid, pGid);
+    }
+  }
+  return rc;
+}
+
+/*
+** Open the file zPath.
+**
+** Previously, the SQLite OS layer used three functions in place of this
+** one:
+**
+**     sqlite3OsOpenReadWrite();
+**     sqlite3OsOpenReadOnly();
+**     sqlite3OsOpenExclusive();
+**
+** These calls correspond to the following combinations of flags:
+**
+**     ReadWrite() ->     (READWRITE | CREATE)
+**     ReadOnly()  ->     (READONLY)
+**     OpenExclusive() -> (READWRITE | CREATE | EXCLUSIVE)
+**
+** The old OpenExclusive() accepted a boolean argument - "delFlag". If
+** true, the file was configured to be automatically deleted when the
+** file handle closed. To achieve the same effect using this new
+** interface, add the DELETEONCLOSE flag to those specified above for
+** OpenExclusive().
+*/
+static int unixOpen(
+  sqlite3_vfs *pVfs,           /* The VFS for which this is the xOpen method */
+  const char *zPath,           /* Pathname of file to be opened */
+  sqlite3_file *pFile,         /* The file descriptor to be filled in */
+  int flags,                   /* Input flags to control the opening */
+  int *pOutFlags               /* Output flags returned to SQLite core */
+){
+  unixFile *p = (unixFile *)pFile;
+  int fd = -1;                   /* File descriptor returned by open() */
+  int openFlags = 0;             /* Flags to pass to open() */
+  int eType = flags&0x0FFF00;  /* Type of file to open */
+  int noLock;                    /* True to omit locking primitives */
+  int rc = SQLITE_OK;            /* Function Return Code */
+  int ctrlFlags = 0;             /* UNIXFILE_* flags */
+
+  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
+  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
+  int isCreate     = (flags & SQLITE_OPEN_CREATE);
+  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
+  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
+#if SQLITE_ENABLE_LOCKING_STYLE
+  int isAutoProxy  = (flags & SQLITE_OPEN_AUTOPROXY);
+#endif
+#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
+  struct statfs fsInfo;
+#endif
+
+  /* If creating a super- or main-file journal, this function will open
+  ** a file-descriptor on the directory too. The first time unixSync()
+  ** is called the directory file descriptor will be fsync()ed and close()d.
+  */
+  int isNewJrnl = (isCreate && (
+        eType==SQLITE_OPEN_SUPER_JOURNAL
+     || eType==SQLITE_OPEN_MAIN_JOURNAL
+     || eType==SQLITE_OPEN_WAL
+  ));
+
+  /* If argument zPath is a NULL pointer, this function is required to open
+  ** a temporary file. Use this buffer to store the file name in.
+  */
+  char zTmpname[MAX_PATHNAME+2];
+  const char *zName = zPath;
+
+  /* Check the following statements are true:
+  **
+  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and
+  **   (b) if CREATE is set, then READWRITE must also be set, and
+  **   (c) if EXCLUSIVE is set, then CREATE must also be set.
+  **   (d) if DELETEONCLOSE is set, then CREATE must also be set.
+  */
+  assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly));
+  assert(isCreate==0 || isReadWrite);
+  assert(isExclusive==0 || isCreate);
+  assert(isDelete==0 || isCreate);
+
+  /* The main DB, main journal, WAL file and super-journal are never
+  ** automatically deleted. Nor are they ever temporary files.  */
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_DB );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_SUPER_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_WAL );
+
+  /* Assert that the upper layer has set one of the "file-type" flags. */
+  assert( eType==SQLITE_OPEN_MAIN_DB      || eType==SQLITE_OPEN_TEMP_DB
+       || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL
+       || eType==SQLITE_OPEN_SUBJOURNAL   || eType==SQLITE_OPEN_SUPER_JOURNAL
+       || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL
+  );
+
+  /* Detect a pid change and reset the PRNG.  There is a race condition
+  ** here such that two or more threads all trying to open databases at
+  ** the same instant might all reset the PRNG.  But multiple resets
+  ** are harmless.
+  */
+  if( randomnessPid!=osGetpid(0) ){
+    randomnessPid = osGetpid(0);
+    sqlite3_randomness(0,0);
+  }
+  memset(p, 0, sizeof(unixFile));
+
+#ifdef SQLITE_ASSERT_NO_FILES
+  /* Applications that never read or write a persistent disk files */
+  assert( zName==0 );
+#endif
+
+  if( eType==SQLITE_OPEN_MAIN_DB ){
+    UnixUnusedFd *pUnused;
+    pUnused = findReusableFd(zName, flags);
+    if( pUnused ){
+      fd = pUnused->fd;
+    }else{
+      pUnused = sqlite3_malloc64(sizeof(*pUnused));
+      if( !pUnused ){
+        return SQLITE_NOMEM_BKPT;
+      }
+    }
+    p->pPreallocatedUnused = pUnused;
+
+    /* Database filenames are double-zero terminated if they are not
+    ** URIs with parameters.  Hence, they can always be passed into
+    ** sqlite3_uri_parameter(). */
+    assert( (flags & SQLITE_OPEN_URI) || zName[strlen(zName)+1]==0 );
+
+  }else if( !zName ){
+    /* If zName is NULL, the upper layer is requesting a temp file. */
+    assert(isDelete && !isNewJrnl);
+    rc = unixGetTempname(pVfs->mxPathname, zTmpname);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    zName = zTmpname;
+
+    /* Generated temporary filenames are always double-zero terminated
+    ** for use by sqlite3_uri_parameter(). */
+    assert( zName[strlen(zName)+1]==0 );
+  }
+
+  /* Determine the value of the flags parameter passed to POSIX function
+  ** open(). These must be calculated even if open() is not called, as
+  ** they may be stored as part of the file handle and used by the
+  ** 'conch file' locking functions later on.  */
+  if( isReadonly )  openFlags |= O_RDONLY;
+  if( isReadWrite ) openFlags |= O_RDWR;
+  if( isCreate )    openFlags |= O_CREAT;
+  if( isExclusive ) openFlags |= (O_EXCL|O_NOFOLLOW);
+  openFlags |= (O_LARGEFILE|O_BINARY|O_NOFOLLOW);
+
+  if( fd<0 ){
+    mode_t openMode;              /* Permissions to create file with */
+    uid_t uid;                    /* Userid for the file */
+    gid_t gid;                    /* Groupid for the file */
+    rc = findCreateFileMode(zName, flags, &openMode, &uid, &gid);
+    if( rc!=SQLITE_OK ){
+      assert( !p->pPreallocatedUnused );
+      assert( eType==SQLITE_OPEN_WAL || eType==SQLITE_OPEN_MAIN_JOURNAL );
+      return rc;
+    }
+    fd = robust_open(zName, openFlags, openMode);
+    OSTRACE(("OPENX   %-3d %s 0%o\n", fd, zName, openFlags));
+    assert( !isExclusive || (openFlags & O_CREAT)!=0 );
+    if( fd<0 ){
+      if( isNewJrnl && errno==EACCES && osAccess(zName, F_OK) ){
+        /* If unable to create a journal because the directory is not
+        ** writable, change the error code to indicate that. */
+        rc = SQLITE_READONLY_DIRECTORY;
+      }else if( errno!=EISDIR && isReadWrite ){
+        /* Failed to open the file for read/write access. Try read-only. */
+        UnixUnusedFd *pReadonly = 0;
+        flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
+        openFlags &= ~(O_RDWR|O_CREAT);
+        flags |= SQLITE_OPEN_READONLY;
+        openFlags |= O_RDONLY;
+        isReadonly = 1;
+        pReadonly = findReusableFd(zName, flags);
+        if( pReadonly ){
+          fd = pReadonly->fd;
+          sqlite3_free(pReadonly);
+        }else{
+          fd = robust_open(zName, openFlags, openMode);
+        }
+      }
+    }
+    if( fd<0 ){
+      int rc2 = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zName);
+      if( rc==SQLITE_OK ) rc = rc2;
+      goto open_finished;
+    }
+
+    /* The owner of the rollback journal or WAL file should always be the
+    ** same as the owner of the database file.  Try to ensure that this is
+    ** the case.  The chown() system call will be a no-op if the current
+    ** process lacks root privileges, be we should at least try.  Without
+    ** this step, if a root process opens a database file, it can leave
+    ** behinds a journal/WAL that is owned by root and hence make the
+    ** database inaccessible to unprivileged processes.
+    **
+    ** If openMode==0, then that means uid and gid are not set correctly
+    ** (probably because SQLite is configured to use 8+3 filename mode) and
+    ** in that case we do not want to attempt the chown().
+    */
+    if( openMode && (flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL))!=0 ){
+      robustFchown(fd, uid, gid);
+    }
+  }
+  assert( fd>=0 );
+  if( pOutFlags ){
+    *pOutFlags = flags;
+  }
+
+  if( p->pPreallocatedUnused ){
+    p->pPreallocatedUnused->fd = fd;
+    p->pPreallocatedUnused->flags =
+                          flags & (SQLITE_OPEN_READONLY|SQLITE_OPEN_READWRITE);
+  }
+
+  if( isDelete ){
+#if OS_VXWORKS
+    zPath = zName;
+#elif defined(SQLITE_UNLINK_AFTER_CLOSE)
+    zPath = sqlite3_mprintf("%s", zName);
+    if( zPath==0 ){
+      robust_close(p, fd, __LINE__);
+      return SQLITE_NOMEM_BKPT;
+    }
+#else
+    osUnlink(zName);
+#endif
+  }
+#if SQLITE_ENABLE_LOCKING_STYLE
+  else{
+    p->openFlags = openFlags;
+  }
+#endif
+
+#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
+  if( fstatfs(fd, &fsInfo) == -1 ){
+    storeLastErrno(p, errno);
+    robust_close(p, fd, __LINE__);
+    return SQLITE_IOERR_ACCESS;
+  }
+  if (0 == strncmp("msdos", fsInfo.f_fstypename, 5)) {
+    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
+  }
+  if (0 == strncmp("exfat", fsInfo.f_fstypename, 5)) {
+    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
+  }
+#endif
+
+  /* Set up appropriate ctrlFlags */
+  if( isDelete )                ctrlFlags |= UNIXFILE_DELETE;
+  if( isReadonly )              ctrlFlags |= UNIXFILE_RDONLY;
+  noLock = eType!=SQLITE_OPEN_MAIN_DB;
+  if( noLock )                  ctrlFlags |= UNIXFILE_NOLOCK;
+  if( isNewJrnl )               ctrlFlags |= UNIXFILE_DIRSYNC;
+  if( flags & SQLITE_OPEN_URI ) ctrlFlags |= UNIXFILE_URI;
+
+#if SQLITE_ENABLE_LOCKING_STYLE
+#if SQLITE_PREFER_PROXY_LOCKING
+  isAutoProxy = 1;
+#endif
+  if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){
+    char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING");
+    int useProxy = 0;
+
+    /* SQLITE_FORCE_PROXY_LOCKING==1 means force always use proxy, 0 means
+    ** never use proxy, NULL means use proxy for non-local files only.  */
+    if( envforce!=NULL ){
+      useProxy = atoi(envforce)>0;
+    }else{
+      useProxy = !(fsInfo.f_flags&MNT_LOCAL);
+    }
+    if( useProxy ){
+      rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);
+      if( rc==SQLITE_OK ){
+        rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:");
+        if( rc!=SQLITE_OK ){
+          /* Use unixClose to clean up the resources added in fillInUnixFile
+          ** and clear all the structure's references.  Specifically,
+          ** pFile->pMethods will be NULL so sqlite3OsClose will be a no-op
+          */
+          unixClose(pFile);
+          return rc;
+        }
+      }
+      goto open_finished;
+    }
+  }
+#endif
+
+  assert( zPath==0 || zPath[0]=='/'
+      || eType==SQLITE_OPEN_SUPER_JOURNAL || eType==SQLITE_OPEN_MAIN_JOURNAL
+  );
+  rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);
+
+open_finished:
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(p->pPreallocatedUnused);
+  }
+  return rc;
+}
+
+
+/*
+** Delete the file at zPath. If the dirSync argument is true, fsync()
+** the directory after deleting the file.
+*/
+static int unixDelete(
+  sqlite3_vfs *NotUsed,     /* VFS containing this as the xDelete method */
+  const char *zPath,        /* Name of file to be deleted */
+  int dirSync               /* If true, fsync() directory after deleting file */
+){
+  int rc = SQLITE_OK;
+  UNUSED_PARAMETER(NotUsed);
+  SimulateIOError(return SQLITE_IOERR_DELETE);
+  if( osUnlink(zPath)==(-1) ){
+    if( errno==ENOENT
+#if OS_VXWORKS
+        || osAccess(zPath,0)!=0
+#endif
+    ){
+      rc = SQLITE_IOERR_DELETE_NOENT;
+    }else{
+      rc = unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
+    }
+    return rc;
+  }
+#ifndef SQLITE_DISABLE_DIRSYNC
+  if( (dirSync & 1)!=0 ){
+    int fd;
+    rc = osOpenDirectory(zPath, &fd);
+    if( rc==SQLITE_OK ){
+      if( full_fsync(fd,0,0) ){
+        rc = unixLogError(SQLITE_IOERR_DIR_FSYNC, "fsync", zPath);
+      }
+      robust_close(0, fd, __LINE__);
+    }else{
+      assert( rc==SQLITE_CANTOPEN );
+      rc = SQLITE_OK;
+    }
+  }
+#endif
+  return rc;
+}
+
+/*
+** Test the existence of or access permissions of file zPath. The
+** test performed depends on the value of flags:
+**
+**     SQLITE_ACCESS_EXISTS: Return 1 if the file exists
+**     SQLITE_ACCESS_READWRITE: Return 1 if the file is read and writable.
+**     SQLITE_ACCESS_READONLY: Return 1 if the file is readable.
+**
+** Otherwise return 0.
+*/
+static int unixAccess(
+  sqlite3_vfs *NotUsed,   /* The VFS containing this xAccess method */
+  const char *zPath,      /* Path of the file to examine */
+  int flags,              /* What do we want to learn about the zPath file? */
+  int *pResOut            /* Write result boolean here */
+){
+  UNUSED_PARAMETER(NotUsed);
+  SimulateIOError( return SQLITE_IOERR_ACCESS; );
+  assert( pResOut!=0 );
+
+  /* The spec says there are three possible values for flags.  But only
+  ** two of them are actually used */
+  assert( flags==SQLITE_ACCESS_EXISTS || flags==SQLITE_ACCESS_READWRITE );
+
+  if( flags==SQLITE_ACCESS_EXISTS ){
+    struct stat buf;
+    *pResOut = 0==osStat(zPath, &buf) &&
+                (!S_ISREG(buf.st_mode) || buf.st_size>0);
+  }else{
+    *pResOut = osAccess(zPath, W_OK|R_OK)==0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** A pathname under construction
+*/
+typedef struct DbPath DbPath;
+struct DbPath {
+  int rc;           /* Non-zero following any error */
+  int nSymlink;     /* Number of symlinks resolved */
+  char *zOut;       /* Write the pathname here */
+  int nOut;         /* Bytes of space available to zOut[] */
+  int nUsed;        /* Bytes of zOut[] currently being used */
+};
+
+/* Forward reference */
+static void appendAllPathElements(DbPath*,const char*);
+
+/*
+** Append a single path element to the DbPath under construction
+*/
+static void appendOnePathElement(
+  DbPath *pPath,       /* Path under construction, to which to append zName */
+  const char *zName,   /* Name to append to pPath.  Not zero-terminated */
+  int nName            /* Number of significant bytes in zName */
+){
+  assert( nName>0 );
+  assert( zName!=0 );
+  if( zName[0]=='.' ){
+    if( nName==1 ) return;
+    if( zName[1]=='.' && nName==2 ){
+      if( pPath->nUsed>1 ){
+        assert( pPath->zOut[0]=='/' );
+        while( pPath->zOut[--pPath->nUsed]!='/' ){}
+      }
+      return;
+    }
+  }
+  if( pPath->nUsed + nName + 2 >= pPath->nOut ){
+    pPath->rc = SQLITE_ERROR;
+    return;
+  }
+  pPath->zOut[pPath->nUsed++] = '/';
+  memcpy(&pPath->zOut[pPath->nUsed], zName, nName);
+  pPath->nUsed += nName;
+#if defined(HAVE_READLINK) && defined(HAVE_LSTAT)
+  if( pPath->rc==SQLITE_OK ){
+    const char *zIn;
+    struct stat buf;
+    pPath->zOut[pPath->nUsed] = 0;
+    zIn = pPath->zOut;
+    if( osLstat(zIn, &buf)!=0 ){
+      if( errno!=ENOENT ){
+        pPath->rc = unixLogError(SQLITE_CANTOPEN_BKPT, "lstat", zIn);
+      }
+    }else if( S_ISLNK(buf.st_mode) ){
+      ssize_t got;
+      char zLnk[SQLITE_MAX_PATHLEN+2];
+      if( pPath->nSymlink++ > SQLITE_MAX_SYMLINK ){
+        pPath->rc = SQLITE_CANTOPEN_BKPT;
+        return;
+      }
+      got = osReadlink(zIn, zLnk, sizeof(zLnk)-2);
+      if( got<=0 || got>=(ssize_t)sizeof(zLnk)-2 ){
+        pPath->rc = unixLogError(SQLITE_CANTOPEN_BKPT, "readlink", zIn);
+        return;
+      }
+      zLnk[got] = 0;
+      if( zLnk[0]=='/' ){
+        pPath->nUsed = 0;
+      }else{
+        pPath->nUsed -= nName + 1;
+      }
+      appendAllPathElements(pPath, zLnk);
+    }
+  }
+#endif
+}
+
+/*
+** Append all path elements in zPath to the DbPath under construction.
+*/
+static void appendAllPathElements(
+  DbPath *pPath,       /* Path under construction, to which to append zName */
+  const char *zPath    /* Path to append to pPath.  Is zero-terminated */
+){
+  int i = 0;
+  int j = 0;
+  do{
+    while( zPath[i] && zPath[i]!='/' ){ i++; }
+    if( i>j ){
+      appendOnePathElement(pPath, &zPath[j], i-j);
+    }
+    j = i+1;
+  }while( zPath[i++] );
+}
+
+/*
+** Turn a relative pathname into a full pathname. The relative path
+** is stored as a nul-terminated string in the buffer pointed to by
+** zPath.
+**
+** zOut points to a buffer of at least sqlite3_vfs.mxPathname bytes
+** (in this case, MAX_PATHNAME bytes). The full-path is written to
+** this buffer before returning.
+*/
+static int unixFullPathname(
+  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
+  const char *zPath,            /* Possibly relative input path */
+  int nOut,                     /* Size of output buffer in bytes */
+  char *zOut                    /* Output buffer */
+){
+  DbPath path;
+  UNUSED_PARAMETER(pVfs);
+  path.rc = 0;
+  path.nUsed = 0;
+  path.nSymlink = 0;
+  path.nOut = nOut;
+  path.zOut = zOut;
+  if( zPath[0]!='/' ){
+    char zPwd[SQLITE_MAX_PATHLEN+2];
+    if( osGetcwd(zPwd, sizeof(zPwd)-2)==0 ){
+      return unixLogError(SQLITE_CANTOPEN_BKPT, "getcwd", zPath);
+    }
+    appendAllPathElements(&path, zPwd);
+  }
+  appendAllPathElements(&path, zPath);
+  zOut[path.nUsed] = 0;
+  if( path.rc || path.nUsed<2 ) return SQLITE_CANTOPEN_BKPT;
+  if( path.nSymlink ) return SQLITE_OK_SYMLINK;
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Interfaces for opening a shared library, finding entry points
+** within the shared library, and closing the shared library.
+*/
+#include <dlfcn.h>
+static void *unixDlOpen(sqlite3_vfs *NotUsed, const char *zFilename){
+  UNUSED_PARAMETER(NotUsed);
+  return dlopen(zFilename, RTLD_NOW | RTLD_GLOBAL);
+}
+
+/*
+** SQLite calls this function immediately after a call to unixDlSym() or
+** unixDlOpen() fails (returns a null pointer). If a more detailed error
+** message is available, it is written to zBufOut. If no error message
+** is available, zBufOut is left unmodified and SQLite uses a default
+** error message.
+*/
+static void unixDlError(sqlite3_vfs *NotUsed, int nBuf, char *zBufOut){
+  const char *zErr;
+  UNUSED_PARAMETER(NotUsed);
+  unixEnterMutex();
+  zErr = dlerror();
+  if( zErr ){
+    sqlite3_snprintf(nBuf, zBufOut, "%s", zErr);
+  }
+  unixLeaveMutex();
+}
+static void (*unixDlSym(sqlite3_vfs *NotUsed, void *p, const char*zSym))(void){
+  /*
+  ** GCC with -pedantic-errors says that C90 does not allow a void* to be
+  ** cast into a pointer to a function.  And yet the library dlsym() routine
+  ** returns a void* which is really a pointer to a function.  So how do we
+  ** use dlsym() with -pedantic-errors?
+  **
+  ** Variable x below is defined to be a pointer to a function taking
+  ** parameters void* and const char* and returning a pointer to a function.
+  ** We initialize x by assigning it a pointer to the dlsym() function.
+  ** (That assignment requires a cast.)  Then we call the function that
+  ** x points to.
+  **
+  ** This work-around is unlikely to work correctly on any system where
+  ** you really cannot cast a function pointer into void*.  But then, on the
+  ** other hand, dlsym() will not work on such a system either, so we have
+  ** not really lost anything.
+  */
+  void (*(*x)(void*,const char*))(void);
+  UNUSED_PARAMETER(NotUsed);
+  x = (void(*(*)(void*,const char*))(void))dlsym;
+  return (*x)(p, zSym);
+}
+static void unixDlClose(sqlite3_vfs *NotUsed, void *pHandle){
+  UNUSED_PARAMETER(NotUsed);
+  dlclose(pHandle);
+}
+#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
+  #define unixDlOpen  0
+  #define unixDlError 0
+  #define unixDlSym   0
+  #define unixDlClose 0
+#endif
+
+/*
+** Write nBuf bytes of random data to the supplied buffer zBuf.
+*/
+static int unixRandomness(sqlite3_vfs *NotUsed, int nBuf, char *zBuf){
+  UNUSED_PARAMETER(NotUsed);
+  assert((size_t)nBuf>=(sizeof(time_t)+sizeof(int)));
+
+  /* We have to initialize zBuf to prevent valgrind from reporting
+  ** errors.  The reports issued by valgrind are incorrect - we would
+  ** prefer that the randomness be increased by making use of the
+  ** uninitialized space in zBuf - but valgrind errors tend to worry
+  ** some users.  Rather than argue, it seems easier just to initialize
+  ** the whole array and silence valgrind, even if that means less randomness
+  ** in the random seed.
+  **
+  ** When testing, initializing zBuf[] to zero is all we do.  That means
+  ** that we always use the same random number sequence.  This makes the
+  ** tests repeatable.
+  */
+  memset(zBuf, 0, nBuf);
+  randomnessPid = osGetpid(0);
+#if !defined(SQLITE_TEST) && !defined(SQLITE_OMIT_RANDOMNESS)
+  {
+    int fd, got;
+    fd = robust_open("/dev/urandom", O_RDONLY, 0);
+    if( fd<0 ){
+      time_t t;
+      time(&t);
+      memcpy(zBuf, &t, sizeof(t));
+      memcpy(&zBuf[sizeof(t)], &randomnessPid, sizeof(randomnessPid));
+      assert( sizeof(t)+sizeof(randomnessPid)<=(size_t)nBuf );
+      nBuf = sizeof(t) + sizeof(randomnessPid);
+    }else{
+      do{ got = osRead(fd, zBuf, nBuf); }while( got<0 && errno==EINTR );
+      robust_close(0, fd, __LINE__);
+    }
+  }
+#endif
+  return nBuf;
+}
+
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+** The argument is the number of microseconds we want to sleep.
+** The return value is the number of microseconds of sleep actually
+** requested from the underlying operating system, a number which
+** might be greater than or equal to the argument, but not less
+** than the argument.
+*/
+static int unixSleep(sqlite3_vfs *NotUsed, int microseconds){
+#if !defined(HAVE_NANOSLEEP) || HAVE_NANOSLEEP+0
+  struct timespec sp;
+  sp.tv_sec = microseconds / 1000000;
+  sp.tv_nsec = (microseconds % 1000000) * 1000;
+
+  /* Almost all modern unix systems support nanosleep().  But if you are
+  ** compiling for one of the rare exceptions, you can use
+  ** -DHAVE_NANOSLEEP=0 (perhaps in conjuction with -DHAVE_USLEEP if
+  ** usleep() is available) in order to bypass the use of nanosleep() */
+  nanosleep(&sp, NULL);
+
+  UNUSED_PARAMETER(NotUsed);
+  return microseconds;
+#elif defined(HAVE_USLEEP) && HAVE_USLEEP
+  if( microseconds>=1000000 ) sleep(microseconds/1000000);
+  if( microseconds%1000000 ) usleep(microseconds%1000000);
+  UNUSED_PARAMETER(NotUsed);
+  return microseconds;
+#else
+  int seconds = (microseconds+999999)/1000000;
+  sleep(seconds);
+  UNUSED_PARAMETER(NotUsed);
+  return seconds*1000000;
+#endif
+}
+
+/*
+** The following variable, if set to a non-zero value, is interpreted as
+** the number of seconds since 1970 and is used to set the result of
+** sqlite3OsCurrentTime() during testing.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_current_time = 0;  /* Fake system time in seconds since 1970. */
+#endif
+
+/*
+** Find the current time (in Universal Coordinated Time).  Write into *piNow
+** the current time and date as a Julian Day number times 86_400_000.  In
+** other words, write into *piNow the number of milliseconds since the Julian
+** epoch of noon in Greenwich on November 24, 4714 B.C according to the
+** proleptic Gregorian calendar.
+**
+** On success, return SQLITE_OK.  Return SQLITE_ERROR if the time and date
+** cannot be found.
+*/
+static int unixCurrentTimeInt64(sqlite3_vfs *NotUsed, sqlite3_int64 *piNow){
+  static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+  int rc = SQLITE_OK;
+#if defined(NO_GETTOD)
+  time_t t;
+  time(&t);
+  *piNow = ((sqlite3_int64)t)*1000 + unixEpoch;
+#elif OS_VXWORKS
+  struct timespec sNow;
+  clock_gettime(CLOCK_REALTIME, &sNow);
+  *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_nsec/1000000;
+#else
+  struct timeval sNow;
+  (void)gettimeofday(&sNow, 0);  /* Cannot fail given valid arguments */
+  *piNow = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_usec/1000;
+#endif
+
+#ifdef SQLITE_TEST
+  if( sqlite3_current_time ){
+    *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch;
+  }
+#endif
+  UNUSED_PARAMETER(NotUsed);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Find the current time (in Universal Coordinated Time).  Write the
+** current time and date as a Julian Day number into *prNow and
+** return 0.  Return 1 if the time and date cannot be found.
+*/
+static int unixCurrentTime(sqlite3_vfs *NotUsed, double *prNow){
+  sqlite3_int64 i = 0;
+  int rc;
+  UNUSED_PARAMETER(NotUsed);
+  rc = unixCurrentTimeInt64(0, &i);
+  *prNow = i/86400000.0;
+  return rc;
+}
+#else
+# define unixCurrentTime 0
+#endif
+
+/*
+** The xGetLastError() method is designed to return a better
+** low-level error message when operating-system problems come up
+** during SQLite operation.  Only the integer return code is currently
+** used.
+*/
+static int unixGetLastError(sqlite3_vfs *NotUsed, int NotUsed2, char *NotUsed3){
+  UNUSED_PARAMETER(NotUsed);
+  UNUSED_PARAMETER(NotUsed2);
+  UNUSED_PARAMETER(NotUsed3);
+  return errno;
+}
+
+
+/*
+************************ End of sqlite3_vfs methods ***************************
+******************************************************************************/
+
+/******************************************************************************
+************************** Begin Proxy Locking ********************************
+**
+** Proxy locking is a "uber-locking-method" in this sense:  It uses the
+** other locking methods on secondary lock files.  Proxy locking is a
+** meta-layer over top of the primitive locking implemented above.  For
+** this reason, the division that implements of proxy locking is deferred
+** until late in the file (here) after all of the other I/O methods have
+** been defined - so that the primitive locking methods are available
+** as services to help with the implementation of proxy locking.
+**
+****
+**
+** The default locking schemes in SQLite use byte-range locks on the
+** database file to coordinate safe, concurrent access by multiple readers
+** and writers [http://sqlite.org/lockingv3.html].  The five file locking
+** states (UNLOCKED, PENDING, SHARED, RESERVED, EXCLUSIVE) are implemented
+** as POSIX read & write locks over fixed set of locations (via fsctl),
+** on AFP and SMB only exclusive byte-range locks are available via fsctl
+** with _IOWR('z', 23, struct ByteRangeLockPB2) to track the same 5 states.
+** To simulate a F_RDLCK on the shared range, on AFP a randomly selected
+** address in the shared range is taken for a SHARED lock, the entire
+** shared range is taken for an EXCLUSIVE lock):
+**
+**      PENDING_BYTE        0x40000000
+**      RESERVED_BYTE       0x40000001
+**      SHARED_RANGE        0x40000002 -> 0x40000200
+**
+** This works well on the local file system, but shows a nearly 100x
+** slowdown in read performance on AFP because the AFP client disables
+** the read cache when byte-range locks are present.  Enabling the read
+** cache exposes a cache coherency problem that is present on all OS X
+** supported network file systems.  NFS and AFP both observe the
+** close-to-open semantics for ensuring cache coherency
+** [http://nfs.sourceforge.net/#faq_a8], which does not effectively
+** address the requirements for concurrent database access by multiple
+** readers and writers
+** [http://www.nabble.com/SQLite-on-NFS-cache-coherency-td15655701.html].
+**
+** To address the performance and cache coherency issues, proxy file locking
+** changes the way database access is controlled by limiting access to a
+** single host at a time and moving file locks off of the database file
+** and onto a proxy file on the local file system.
+**
+**
+** Using proxy locks
+** -----------------
+**
+** C APIs
+**
+**  sqlite3_file_control(db, dbname, SQLITE_FCNTL_SET_LOCKPROXYFILE,
+**                       <proxy_path> | ":auto:");
+**  sqlite3_file_control(db, dbname, SQLITE_FCNTL_GET_LOCKPROXYFILE,
+**                       &<proxy_path>);
+**
+**
+** SQL pragmas
+**
+**  PRAGMA [database.]lock_proxy_file=<proxy_path> | :auto:
+**  PRAGMA [database.]lock_proxy_file
+**
+** Specifying ":auto:" means that if there is a conch file with a matching
+** host ID in it, the proxy path in the conch file will be used, otherwise
+** a proxy path based on the user's temp dir
+** (via confstr(_CS_DARWIN_USER_TEMP_DIR,...)) will be used and the
+** actual proxy file name is generated from the name and path of the
+** database file.  For example:
+**
+**       For database path "/Users/me/foo.db"
+**       The lock path will be "<tmpdir>/sqliteplocks/_Users_me_foo.db:auto:")
+**
+** Once a lock proxy is configured for a database connection, it can not
+** be removed, however it may be switched to a different proxy path via
+** the above APIs (assuming the conch file is not being held by another
+** connection or process).
+**
+**
+** How proxy locking works
+** -----------------------
+**
+** Proxy file locking relies primarily on two new supporting files:
+**
+**   *  conch file to limit access to the database file to a single host
+**      at a time
+**
+**   *  proxy file to act as a proxy for the advisory locks normally
+**      taken on the database
+**
+** The conch file - to use a proxy file, sqlite must first "hold the conch"
+** by taking an sqlite-style shared lock on the conch file, reading the
+** contents and comparing the host's unique host ID (see below) and lock
+** proxy path against the values stored in the conch.  The conch file is
+** stored in the same directory as the database file and the file name
+** is patterned after the database file name as ".<databasename>-conch".
+** If the conch file does not exist, or its contents do not match the
+** host ID and/or proxy path, then the lock is escalated to an exclusive
+** lock and the conch file contents is updated with the host ID and proxy
+** path and the lock is downgraded to a shared lock again.  If the conch
+** is held by another process (with a shared lock), the exclusive lock
+** will fail and SQLITE_BUSY is returned.
+**
+** The proxy file - a single-byte file used for all advisory file locks
+** normally taken on the database file.   This allows for safe sharing
+** of the database file for multiple readers and writers on the same
+** host (the conch ensures that they all use the same local lock file).
+**
+** Requesting the lock proxy does not immediately take the conch, it is
+** only taken when the first request to lock database file is made.
+** This matches the semantics of the traditional locking behavior, where
+** opening a connection to a database file does not take a lock on it.
+** The shared lock and an open file descriptor are maintained until
+** the connection to the database is closed.
+**
+** The proxy file and the lock file are never deleted so they only need
+** to be created the first time they are used.
+**
+** Configuration options
+** ---------------------
+**
+**  SQLITE_PREFER_PROXY_LOCKING
+**
+**       Database files accessed on non-local file systems are
+**       automatically configured for proxy locking, lock files are
+**       named automatically using the same logic as
+**       PRAGMA lock_proxy_file=":auto:"
+**
+**  SQLITE_PROXY_DEBUG
+**
+**       Enables the logging of error messages during host id file
+**       retrieval and creation
+**
+**  LOCKPROXYDIR
+**
+**       Overrides the default directory used for lock proxy files that
+**       are named automatically via the ":auto:" setting
+**
+**  SQLITE_DEFAULT_PROXYDIR_PERMISSIONS
+**
+**       Permissions to use when creating a directory for storing the
+**       lock proxy files, only used when LOCKPROXYDIR is not set.
+**
+**
+** As mentioned above, when compiled with SQLITE_PREFER_PROXY_LOCKING,
+** setting the environment variable SQLITE_FORCE_PROXY_LOCKING to 1 will
+** force proxy locking to be used for every database file opened, and 0
+** will force automatic proxy locking to be disabled for all database
+** files (explicitly calling the SQLITE_FCNTL_SET_LOCKPROXYFILE pragma or
+** sqlite_file_control API is not affected by SQLITE_FORCE_PROXY_LOCKING).
+*/
+
+/*
+** Proxy locking is only available on MacOSX
+*/
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+
+/*
+** The proxyLockingContext has the path and file structures for the remote
+** and local proxy files in it
+*/
+typedef struct proxyLockingContext proxyLockingContext;
+struct proxyLockingContext {
+  unixFile *conchFile;         /* Open conch file */
+  char *conchFilePath;         /* Name of the conch file */
+  unixFile *lockProxy;         /* Open proxy lock file */
+  char *lockProxyPath;         /* Name of the proxy lock file */
+  char *dbPath;                /* Name of the open file */
+  int conchHeld;               /* 1 if the conch is held, -1 if lockless */
+  int nFails;                  /* Number of conch taking failures */
+  void *oldLockingContext;     /* Original lockingcontext to restore on close */
+  sqlite3_io_methods const *pOldMethod;     /* Original I/O methods for close */
+};
+
+/*
+** The proxy lock file path for the database at dbPath is written into lPath,
+** which must point to valid, writable memory large enough for a maxLen length
+** file path.
+*/
+static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
+  int len;
+  int dbLen;
+  int i;
+
+#ifdef LOCKPROXYDIR
+  len = strlcpy(lPath, LOCKPROXYDIR, maxLen);
+#else
+# ifdef _CS_DARWIN_USER_TEMP_DIR
+  {
+    if( !confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen) ){
+      OSTRACE(("GETLOCKPATH  failed %s errno=%d pid=%d\n",
+               lPath, errno, osGetpid(0)));
+      return SQLITE_IOERR_LOCK;
+    }
+    len = strlcat(lPath, "sqliteplocks", maxLen);
+  }
+# else
+  len = strlcpy(lPath, "/tmp/", maxLen);
+# endif
+#endif
+
+  if( lPath[len-1]!='/' ){
+    len = strlcat(lPath, "/", maxLen);
+  }
+
+  /* transform the db path to a unique cache name */
+  dbLen = (int)strlen(dbPath);
+  for( i=0; i<dbLen && (i+len+7)<(int)maxLen; i++){
+    char c = dbPath[i];
+    lPath[i+len] = (c=='/')?'_':c;
+  }
+  lPath[i+len]='\0';
+  strlcat(lPath, ":auto:", maxLen);
+  OSTRACE(("GETLOCKPATH  proxy lock path=%s pid=%d\n", lPath, osGetpid(0)));
+  return SQLITE_OK;
+}
+
+/*
+ ** Creates the lock file and any missing directories in lockPath
+ */
+static int proxyCreateLockPath(const char *lockPath){
+  int i, len;
+  char buf[MAXPATHLEN];
+  int start = 0;
+
+  assert(lockPath!=NULL);
+  /* try to create all the intermediate directories */
+  len = (int)strlen(lockPath);
+  buf[0] = lockPath[0];
+  for( i=1; i<len; i++ ){
+    if( lockPath[i] == '/' && (i - start > 0) ){
+      /* only mkdir if leaf dir != "." or "/" or ".." */
+      if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/')
+         || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){
+        buf[i]='\0';
+        if( osMkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
+          int err=errno;
+          if( err!=EEXIST ) {
+            OSTRACE(("CREATELOCKPATH  FAILED creating %s, "
+                     "'%s' proxy lock path=%s pid=%d\n",
+                     buf, strerror(err), lockPath, osGetpid(0)));
+            return err;
+          }
+        }
+      }
+      start=i+1;
+    }
+    buf[i] = lockPath[i];
+  }
+  OSTRACE(("CREATELOCKPATH  proxy lock path=%s pid=%d\n",lockPath,osGetpid(0)));
+  return 0;
+}
+
+/*
+** Create a new VFS file descriptor (stored in memory obtained from
+** sqlite3_malloc) and open the file named "path" in the file descriptor.
+**
+** The caller is responsible not only for closing the file descriptor
+** but also for freeing the memory associated with the file descriptor.
+*/
+static int proxyCreateUnixFile(
+    const char *path,        /* path for the new unixFile */
+    unixFile **ppFile,       /* unixFile created and returned by ref */
+    int islockfile           /* if non zero missing dirs will be created */
+) {
+  int fd = -1;
+  unixFile *pNew;
+  int rc = SQLITE_OK;
+  int openFlags = O_RDWR | O_CREAT | O_NOFOLLOW;
+  sqlite3_vfs dummyVfs;
+  int terrno = 0;
+  UnixUnusedFd *pUnused = NULL;
+
+  /* 1. first try to open/create the file
+  ** 2. if that fails, and this is a lock file (not-conch), try creating
+  ** the parent directories and then try again.
+  ** 3. if that fails, try to open the file read-only
+  ** otherwise return BUSY (if lock file) or CANTOPEN for the conch file
+  */
+  pUnused = findReusableFd(path, openFlags);
+  if( pUnused ){
+    fd = pUnused->fd;
+  }else{
+    pUnused = sqlite3_malloc64(sizeof(*pUnused));
+    if( !pUnused ){
+      return SQLITE_NOMEM_BKPT;
+    }
+  }
+  if( fd<0 ){
+    fd = robust_open(path, openFlags, 0);
+    terrno = errno;
+    if( fd<0 && errno==ENOENT && islockfile ){
+      if( proxyCreateLockPath(path) == SQLITE_OK ){
+        fd = robust_open(path, openFlags, 0);
+      }
+    }
+  }
+  if( fd<0 ){
+    openFlags = O_RDONLY | O_NOFOLLOW;
+    fd = robust_open(path, openFlags, 0);
+    terrno = errno;
+  }
+  if( fd<0 ){
+    if( islockfile ){
+      return SQLITE_BUSY;
+    }
+    switch (terrno) {
+      case EACCES:
+        return SQLITE_PERM;
+      case EIO:
+        return SQLITE_IOERR_LOCK; /* even though it is the conch */
+      default:
+        return SQLITE_CANTOPEN_BKPT;
+    }
+  }
+
+  pNew = (unixFile *)sqlite3_malloc64(sizeof(*pNew));
+  if( pNew==NULL ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto end_create_proxy;
+  }
+  memset(pNew, 0, sizeof(unixFile));
+  pNew->openFlags = openFlags;
+  memset(&dummyVfs, 0, sizeof(dummyVfs));
+  dummyVfs.pAppData = (void*)&autolockIoFinder;
+  dummyVfs.zName = "dummy";
+  pUnused->fd = fd;
+  pUnused->flags = openFlags;
+  pNew->pPreallocatedUnused = pUnused;
+
+  rc = fillInUnixFile(&dummyVfs, fd, (sqlite3_file*)pNew, path, 0);
+  if( rc==SQLITE_OK ){
+    *ppFile = pNew;
+    return SQLITE_OK;
+  }
+end_create_proxy:
+  robust_close(pNew, fd, __LINE__);
+  sqlite3_free(pNew);
+  sqlite3_free(pUnused);
+  return rc;
+}
+
+#ifdef SQLITE_TEST
+/* simulate multiple hosts by creating unique hostid file paths */
+SQLITE_API int sqlite3_hostid_num = 0;
+#endif
+
+#define PROXY_HOSTIDLEN    16  /* conch file host id length */
+
+#if HAVE_GETHOSTUUID
+/* Not always defined in the headers as it ought to be */
+extern int gethostuuid(uuid_t id, const struct timespec *wait);
+#endif
+
+/* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN
+** bytes of writable memory.
+*/
+static int proxyGetHostID(unsigned char *pHostID, int *pError){
+  assert(PROXY_HOSTIDLEN == sizeof(uuid_t));
+  memset(pHostID, 0, PROXY_HOSTIDLEN);
+#if HAVE_GETHOSTUUID
+  {
+    struct timespec timeout = {1, 0}; /* 1 sec timeout */
+    if( gethostuuid(pHostID, &timeout) ){
+      int err = errno;
+      if( pError ){
+        *pError = err;
+      }
+      return SQLITE_IOERR;
+    }
+  }
+#else
+  UNUSED_PARAMETER(pError);
+#endif
+#ifdef SQLITE_TEST
+  /* simulate multiple hosts by creating unique hostid file paths */
+  if( sqlite3_hostid_num != 0){
+    pHostID[0] = (char)(pHostID[0] + (char)(sqlite3_hostid_num & 0xFF));
+  }
+#endif
+
+  return SQLITE_OK;
+}
+
+/* The conch file contains the header, host id and lock file path
+ */
+#define PROXY_CONCHVERSION 2   /* 1-byte header, 16-byte host id, path */
+#define PROXY_HEADERLEN    1   /* conch file header length */
+#define PROXY_PATHINDEX    (PROXY_HEADERLEN+PROXY_HOSTIDLEN)
+#define PROXY_MAXCONCHLEN  (PROXY_HEADERLEN+PROXY_HOSTIDLEN+MAXPATHLEN)
+
+/*
+** Takes an open conch file, copies the contents to a new path and then moves
+** it back.  The newly created file's file descriptor is assigned to the
+** conch file structure and finally the original conch file descriptor is
+** closed.  Returns zero if successful.
+*/
+static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){
+  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+  unixFile *conchFile = pCtx->conchFile;
+  char tPath[MAXPATHLEN];
+  char buf[PROXY_MAXCONCHLEN];
+  char *cPath = pCtx->conchFilePath;
+  size_t readLen = 0;
+  size_t pathLen = 0;
+  char errmsg[64] = "";
+  int fd = -1;
+  int rc = -1;
+  UNUSED_PARAMETER(myHostID);
+
+  /* create a new path by replace the trailing '-conch' with '-break' */
+  pathLen = strlcpy(tPath, cPath, MAXPATHLEN);
+  if( pathLen>MAXPATHLEN || pathLen<6 ||
+     (strlcpy(&tPath[pathLen-5], "break", 6) != 5) ){
+    sqlite3_snprintf(sizeof(errmsg),errmsg,"path error (len %d)",(int)pathLen);
+    goto end_breaklock;
+  }
+  /* read the conch content */
+  readLen = osPread(conchFile->h, buf, PROXY_MAXCONCHLEN, 0);
+  if( readLen<PROXY_PATHINDEX ){
+    sqlite3_snprintf(sizeof(errmsg),errmsg,"read error (len %d)",(int)readLen);
+    goto end_breaklock;
+  }
+  /* write it out to the temporary break file */
+  fd = robust_open(tPath, (O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW), 0);
+  if( fd<0 ){
+    sqlite3_snprintf(sizeof(errmsg), errmsg, "create failed (%d)", errno);
+    goto end_breaklock;
+  }
+  if( osPwrite(fd, buf, readLen, 0) != (ssize_t)readLen ){
+    sqlite3_snprintf(sizeof(errmsg), errmsg, "write failed (%d)", errno);
+    goto end_breaklock;
+  }
+  if( rename(tPath, cPath) ){
+    sqlite3_snprintf(sizeof(errmsg), errmsg, "rename failed (%d)", errno);
+    goto end_breaklock;
+  }
+  rc = 0;
+  fprintf(stderr, "broke stale lock on %s\n", cPath);
+  robust_close(pFile, conchFile->h, __LINE__);
+  conchFile->h = fd;
+  conchFile->openFlags = O_RDWR | O_CREAT;
+
+end_breaklock:
+  if( rc ){
+    if( fd>=0 ){
+      osUnlink(tPath);
+      robust_close(pFile, fd, __LINE__);
+    }
+    fprintf(stderr, "failed to break stale lock on %s, %s\n", cPath, errmsg);
+  }
+  return rc;
+}
+
+/* Take the requested lock on the conch file and break a stale lock if the
+** host id matches.
+*/
+static int proxyConchLock(unixFile *pFile, uuid_t myHostID, int lockType){
+  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+  unixFile *conchFile = pCtx->conchFile;
+  int rc = SQLITE_OK;
+  int nTries = 0;
+  struct timespec conchModTime;
+
+  memset(&conchModTime, 0, sizeof(conchModTime));
+  do {
+    rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
+    nTries ++;
+    if( rc==SQLITE_BUSY ){
+      /* If the lock failed (busy):
+       * 1st try: get the mod time of the conch, wait 0.5s and try again.
+       * 2nd try: fail if the mod time changed or host id is different, wait
+       *           10 sec and try again
+       * 3rd try: break the lock unless the mod time has changed.
+       */
+      struct stat buf;
+      if( osFstat(conchFile->h, &buf) ){
+        storeLastErrno(pFile, errno);
+        return SQLITE_IOERR_LOCK;
+      }
+
+      if( nTries==1 ){
+        conchModTime = buf.st_mtimespec;
+        unixSleep(0,500000); /* wait 0.5 sec and try the lock again*/
+        continue;
+      }
+
+      assert( nTries>1 );
+      if( conchModTime.tv_sec != buf.st_mtimespec.tv_sec ||
+         conchModTime.tv_nsec != buf.st_mtimespec.tv_nsec ){
+        return SQLITE_BUSY;
+      }
+
+      if( nTries==2 ){
+        char tBuf[PROXY_MAXCONCHLEN];
+        int len = osPread(conchFile->h, tBuf, PROXY_MAXCONCHLEN, 0);
+        if( len<0 ){
+          storeLastErrno(pFile, errno);
+          return SQLITE_IOERR_LOCK;
+        }
+        if( len>PROXY_PATHINDEX && tBuf[0]==(char)PROXY_CONCHVERSION){
+          /* don't break the lock if the host id doesn't match */
+          if( 0!=memcmp(&tBuf[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN) ){
+            return SQLITE_BUSY;
+          }
+        }else{
+          /* don't break the lock on short read or a version mismatch */
+          return SQLITE_BUSY;
+        }
+        unixSleep(0,10000000); /* wait 10 sec and try the lock again */
+        continue;
+      }
+
+      assert( nTries==3 );
+      if( 0==proxyBreakConchLock(pFile, myHostID) ){
+        rc = SQLITE_OK;
+        if( lockType==EXCLUSIVE_LOCK ){
+          rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, SHARED_LOCK);
+        }
+        if( !rc ){
+          rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
+        }
+      }
+    }
+  } while( rc==SQLITE_BUSY && nTries<3 );
+
+  return rc;
+}
+
+/* Takes the conch by taking a shared lock and read the contents conch, if
+** lockPath is non-NULL, the host ID and lock file path must match.  A NULL
+** lockPath means that the lockPath in the conch file will be used if the
+** host IDs match, or a new lock path will be generated automatically
+** and written to the conch file.
+*/
+static int proxyTakeConch(unixFile *pFile){
+  proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+
+  if( pCtx->conchHeld!=0 ){
+    return SQLITE_OK;
+  }else{
+    unixFile *conchFile = pCtx->conchFile;
+    uuid_t myHostID;
+    int pError = 0;
+    char readBuf[PROXY_MAXCONCHLEN];
+    char lockPath[MAXPATHLEN];
+    char *tempLockPath = NULL;
+    int rc = SQLITE_OK;
+    int createConch = 0;
+    int hostIdMatch = 0;
+    int readLen = 0;
+    int tryOldLockPath = 0;
+    int forceNewLockPath = 0;
+
+    OSTRACE(("TAKECONCH  %d for %s pid=%d\n", conchFile->h,
+             (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"),
+             osGetpid(0)));
+
+    rc = proxyGetHostID(myHostID, &pError);
+    if( (rc&0xff)==SQLITE_IOERR ){
+      storeLastErrno(pFile, pError);
+      goto end_takeconch;
+    }
+    rc = proxyConchLock(pFile, myHostID, SHARED_LOCK);
+    if( rc!=SQLITE_OK ){
+      goto end_takeconch;
+    }
+    /* read the existing conch file */
+    readLen = seekAndRead((unixFile*)conchFile, 0, readBuf, PROXY_MAXCONCHLEN);
+    if( readLen<0 ){
+      /* I/O error: lastErrno set by seekAndRead */
+      storeLastErrno(pFile, conchFile->lastErrno);
+      rc = SQLITE_IOERR_READ;
+      goto end_takeconch;
+    }else if( readLen<=(PROXY_HEADERLEN+PROXY_HOSTIDLEN) ||
+             readBuf[0]!=(char)PROXY_CONCHVERSION ){
+      /* a short read or version format mismatch means we need to create a new
+      ** conch file.
+      */
+      createConch = 1;
+    }
+    /* if the host id matches and the lock path already exists in the conch
+    ** we'll try to use the path there, if we can't open that path, we'll
+    ** retry with a new auto-generated path
+    */
+    do { /* in case we need to try again for an :auto: named lock file */
+
+      if( !createConch && !forceNewLockPath ){
+        hostIdMatch = !memcmp(&readBuf[PROXY_HEADERLEN], myHostID,
+                                  PROXY_HOSTIDLEN);
+        /* if the conch has data compare the contents */
+        if( !pCtx->lockProxyPath ){
+          /* for auto-named local lock file, just check the host ID and we'll
+           ** use the local lock file path that's already in there
+           */
+          if( hostIdMatch ){
+            size_t pathLen = (readLen - PROXY_PATHINDEX);
+
+            if( pathLen>=MAXPATHLEN ){
+              pathLen=MAXPATHLEN-1;
+            }
+            memcpy(lockPath, &readBuf[PROXY_PATHINDEX], pathLen);
+            lockPath[pathLen] = 0;
+            tempLockPath = lockPath;
+            tryOldLockPath = 1;
+            /* create a copy of the lock path if the conch is taken */
+            goto end_takeconch;
+          }
+        }else if( hostIdMatch
+               && !strncmp(pCtx->lockProxyPath, &readBuf[PROXY_PATHINDEX],
+                           readLen-PROXY_PATHINDEX)
+        ){
+          /* conch host and lock path match */
+          goto end_takeconch;
+        }
+      }
+
+      /* if the conch isn't writable and doesn't match, we can't take it */
+      if( (conchFile->openFlags&O_RDWR) == 0 ){
+        rc = SQLITE_BUSY;
+        goto end_takeconch;
+      }
+
+      /* either the conch didn't match or we need to create a new one */
+      if( !pCtx->lockProxyPath ){
+        proxyGetLockPath(pCtx->dbPath, lockPath, MAXPATHLEN);
+        tempLockPath = lockPath;
+        /* create a copy of the lock path _only_ if the conch is taken */
+      }
+
+      /* update conch with host and path (this will fail if other process
+      ** has a shared lock already), if the host id matches, use the big
+      ** stick.
+      */
+      futimes(conchFile->h, NULL);
+      if( hostIdMatch && !createConch ){
+        if( conchFile->pInode && conchFile->pInode->nShared>1 ){
+          /* We are trying for an exclusive lock but another thread in this
+           ** same process is still holding a shared lock. */
+          rc = SQLITE_BUSY;
+        } else {
+          rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK);
+        }
+      }else{
+        rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK);
+      }
+      if( rc==SQLITE_OK ){
+        char writeBuffer[PROXY_MAXCONCHLEN];
+        int writeSize = 0;
+
+        writeBuffer[0] = (char)PROXY_CONCHVERSION;
+        memcpy(&writeBuffer[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN);
+        if( pCtx->lockProxyPath!=NULL ){
+          strlcpy(&writeBuffer[PROXY_PATHINDEX], pCtx->lockProxyPath,
+                  MAXPATHLEN);
+        }else{
+          strlcpy(&writeBuffer[PROXY_PATHINDEX], tempLockPath, MAXPATHLEN);
+        }
+        writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]);
+        robust_ftruncate(conchFile->h, writeSize);
+        rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0);
+        full_fsync(conchFile->h,0,0);
+        /* If we created a new conch file (not just updated the contents of a
+         ** valid conch file), try to match the permissions of the database
+         */
+        if( rc==SQLITE_OK && createConch ){
+          struct stat buf;
+          int err = osFstat(pFile->h, &buf);
+          if( err==0 ){
+            mode_t cmode = buf.st_mode&(S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP |
+                                        S_IROTH|S_IWOTH);
+            /* try to match the database file R/W permissions, ignore failure */
+#ifndef SQLITE_PROXY_DEBUG
+            osFchmod(conchFile->h, cmode);
+#else
+            do{
+              rc = osFchmod(conchFile->h, cmode);
+            }while( rc==(-1) && errno==EINTR );
+            if( rc!=0 ){
+              int code = errno;
+              fprintf(stderr, "fchmod %o FAILED with %d %s\n",
+                      cmode, code, strerror(code));
+            } else {
+              fprintf(stderr, "fchmod %o SUCCEDED\n",cmode);
+            }
+          }else{
+            int code = errno;
+            fprintf(stderr, "STAT FAILED[%d] with %d %s\n",
+                    err, code, strerror(code));
+#endif
+          }
+        }
+      }
+      conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK);
+
+    end_takeconch:
+      OSTRACE(("TRANSPROXY: CLOSE  %d\n", pFile->h));
+      if( rc==SQLITE_OK && pFile->openFlags ){
+        int fd;
+        if( pFile->h>=0 ){
+          robust_close(pFile, pFile->h, __LINE__);
+        }
+        pFile->h = -1;
+        fd = robust_open(pCtx->dbPath, pFile->openFlags, 0);
+        OSTRACE(("TRANSPROXY: OPEN  %d\n", fd));
+        if( fd>=0 ){
+          pFile->h = fd;
+        }else{
+          rc=SQLITE_CANTOPEN_BKPT; /* SQLITE_BUSY? proxyTakeConch called
+           during locking */
+        }
+      }
+      if( rc==SQLITE_OK && !pCtx->lockProxy ){
+        char *path = tempLockPath ? tempLockPath : pCtx->lockProxyPath;
+        rc = proxyCreateUnixFile(path, &pCtx->lockProxy, 1);
+        if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && tryOldLockPath ){
+          /* we couldn't create the proxy lock file with the old lock file path
+           ** so try again via auto-naming
+           */
+          forceNewLockPath = 1;
+          tryOldLockPath = 0;
+          continue; /* go back to the do {} while start point, try again */
+        }
+      }
+      if( rc==SQLITE_OK ){
+        /* Need to make a copy of path if we extracted the value
+         ** from the conch file or the path was allocated on the stack
+         */
+        if( tempLockPath ){
+          pCtx->lockProxyPath = sqlite3DbStrDup(0, tempLockPath);
+          if( !pCtx->lockProxyPath ){
+            rc = SQLITE_NOMEM_BKPT;
+          }
+        }
+      }
+      if( rc==SQLITE_OK ){
+        pCtx->conchHeld = 1;
+
+        if( pCtx->lockProxy->pMethod == &afpIoMethods ){
+          afpLockingContext *afpCtx;
+          afpCtx = (afpLockingContext *)pCtx->lockProxy->lockingContext;
+          afpCtx->dbPath = pCtx->lockProxyPath;
+        }
+      } else {
+        conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
+      }
+      OSTRACE(("TAKECONCH  %d %s\n", conchFile->h,
+               rc==SQLITE_OK?"ok":"failed"));
+      return rc;
+    } while (1); /* in case we need to retry the :auto: lock file -
+                 ** we should never get here except via the 'continue' call. */
+  }
+}
+
+/*
+** If pFile holds a lock on a conch file, then release that lock.
+*/
+static int proxyReleaseConch(unixFile *pFile){
+  int rc = SQLITE_OK;         /* Subroutine return code */
+  proxyLockingContext *pCtx;  /* The locking context for the proxy lock */
+  unixFile *conchFile;        /* Name of the conch file */
+
+  pCtx = (proxyLockingContext *)pFile->lockingContext;
+  conchFile = pCtx->conchFile;
+  OSTRACE(("RELEASECONCH  %d for %s pid=%d\n", conchFile->h,
+           (pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"),
+           osGetpid(0)));
+  if( pCtx->conchHeld>0 ){
+    rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
+  }
+  pCtx->conchHeld = 0;
+  OSTRACE(("RELEASECONCH  %d %s\n", conchFile->h,
+           (rc==SQLITE_OK ? "ok" : "failed")));
+  return rc;
+}
+
+/*
+** Given the name of a database file, compute the name of its conch file.
+** Store the conch filename in memory obtained from sqlite3_malloc64().
+** Make *pConchPath point to the new name.  Return SQLITE_OK on success
+** or SQLITE_NOMEM if unable to obtain memory.
+**
+** The caller is responsible for ensuring that the allocated memory
+** space is eventually freed.
+**
+** *pConchPath is set to NULL if a memory allocation error occurs.
+*/
+static int proxyCreateConchPathname(char *dbPath, char **pConchPath){
+  int i;                        /* Loop counter */
+  int len = (int)strlen(dbPath); /* Length of database filename - dbPath */
+  char *conchPath;              /* buffer in which to construct conch name */
+
+  /* Allocate space for the conch filename and initialize the name to
+  ** the name of the original database file. */
+  *pConchPath = conchPath = (char *)sqlite3_malloc64(len + 8);
+  if( conchPath==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  memcpy(conchPath, dbPath, len+1);
+
+  /* now insert a "." before the last / character */
+  for( i=(len-1); i>=0; i-- ){
+    if( conchPath[i]=='/' ){
+      i++;
+      break;
+    }
+  }
+  conchPath[i]='.';
+  while ( i<len ){
+    conchPath[i+1]=dbPath[i];
+    i++;
+  }
+
+  /* append the "-conch" suffix to the file */
+  memcpy(&conchPath[i+1], "-conch", 7);
+  assert( (int)strlen(conchPath) == len+7 );
+
+  return SQLITE_OK;
+}
+
+
+/* Takes a fully configured proxy locking-style unix file and switches
+** the local lock file path
+*/
+static int switchLockProxyPath(unixFile *pFile, const char *path) {
+  proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext;
+  char *oldPath = pCtx->lockProxyPath;
+  int rc = SQLITE_OK;
+
+  if( pFile->eFileLock!=NO_LOCK ){
+    return SQLITE_BUSY;
+  }
+
+  /* nothing to do if the path is NULL, :auto: or matches the existing path */
+  if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ||
+    (oldPath && !strncmp(oldPath, path, MAXPATHLEN)) ){
+    return SQLITE_OK;
+  }else{
+    unixFile *lockProxy = pCtx->lockProxy;
+    pCtx->lockProxy=NULL;
+    pCtx->conchHeld = 0;
+    if( lockProxy!=NULL ){
+      rc=lockProxy->pMethod->xClose((sqlite3_file *)lockProxy);
+      if( rc ) return rc;
+      sqlite3_free(lockProxy);
+    }
+    sqlite3_free(oldPath);
+    pCtx->lockProxyPath = sqlite3DbStrDup(0, path);
+  }
+
+  return rc;
+}
+
+/*
+** pFile is a file that has been opened by a prior xOpen call.  dbPath
+** is a string buffer at least MAXPATHLEN+1 characters in size.
+**
+** This routine find the filename associated with pFile and writes it
+** int dbPath.
+*/
+static int proxyGetDbPathForUnixFile(unixFile *pFile, char *dbPath){
+#if defined(__APPLE__)
+  if( pFile->pMethod == &afpIoMethods ){
+    /* afp style keeps a reference to the db path in the filePath field
+    ** of the struct */
+    assert( (int)strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
+    strlcpy(dbPath, ((afpLockingContext *)pFile->lockingContext)->dbPath,
+            MAXPATHLEN);
+  } else
+#endif
+  if( pFile->pMethod == &dotlockIoMethods ){
+    /* dot lock style uses the locking context to store the dot lock
+    ** file path */
+    int len = strlen((char *)pFile->lockingContext) - strlen(DOTLOCK_SUFFIX);
+    memcpy(dbPath, (char *)pFile->lockingContext, len + 1);
+  }else{
+    /* all other styles use the locking context to store the db file path */
+    assert( strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
+    strlcpy(dbPath, (char *)pFile->lockingContext, MAXPATHLEN);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Takes an already filled in unix file and alters it so all file locking
+** will be performed on the local proxy lock file.  The following fields
+** are preserved in the locking context so that they can be restored and
+** the unix structure properly cleaned up at close time:
+**  ->lockingContext
+**  ->pMethod
+*/
+static int proxyTransformUnixFile(unixFile *pFile, const char *path) {
+  proxyLockingContext *pCtx;
+  char dbPath[MAXPATHLEN+1];       /* Name of the database file */
+  char *lockPath=NULL;
+  int rc = SQLITE_OK;
+
+  if( pFile->eFileLock!=NO_LOCK ){
+    return SQLITE_BUSY;
+  }
+  proxyGetDbPathForUnixFile(pFile, dbPath);
+  if( !path || path[0]=='\0' || !strcmp(path, ":auto:") ){
+    lockPath=NULL;
+  }else{
+    lockPath=(char *)path;
+  }
+
+  OSTRACE(("TRANSPROXY  %d for %s pid=%d\n", pFile->h,
+           (lockPath ? lockPath : ":auto:"), osGetpid(0)));
+
+  pCtx = sqlite3_malloc64( sizeof(*pCtx) );
+  if( pCtx==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  memset(pCtx, 0, sizeof(*pCtx));
+
+  rc = proxyCreateConchPathname(dbPath, &pCtx->conchFilePath);
+  if( rc==SQLITE_OK ){
+    rc = proxyCreateUnixFile(pCtx->conchFilePath, &pCtx->conchFile, 0);
+    if( rc==SQLITE_CANTOPEN && ((pFile->openFlags&O_RDWR) == 0) ){
+      /* if (a) the open flags are not O_RDWR, (b) the conch isn't there, and
+      ** (c) the file system is read-only, then enable no-locking access.
+      ** Ugh, since O_RDONLY==0x0000 we test for !O_RDWR since unixOpen asserts
+      ** that openFlags will have only one of O_RDONLY or O_RDWR.
+      */
+      struct statfs fsInfo;
+      struct stat conchInfo;
+      int goLockless = 0;
+
+      if( osStat(pCtx->conchFilePath, &conchInfo) == -1 ) {
+        int err = errno;
+        if( (err==ENOENT) && (statfs(dbPath, &fsInfo) != -1) ){
+          goLockless = (fsInfo.f_flags&MNT_RDONLY) == MNT_RDONLY;
+        }
+      }
+      if( goLockless ){
+        pCtx->conchHeld = -1; /* read only FS/ lockless */
+        rc = SQLITE_OK;
+      }
+    }
+  }
+  if( rc==SQLITE_OK && lockPath ){
+    pCtx->lockProxyPath = sqlite3DbStrDup(0, lockPath);
+  }
+
+  if( rc==SQLITE_OK ){
+    pCtx->dbPath = sqlite3DbStrDup(0, dbPath);
+    if( pCtx->dbPath==NULL ){
+      rc = SQLITE_NOMEM_BKPT;
+    }
+  }
+  if( rc==SQLITE_OK ){
+    /* all memory is allocated, proxys are created and assigned,
+    ** switch the locking context and pMethod then return.
+    */
+    pCtx->oldLockingContext = pFile->lockingContext;
+    pFile->lockingContext = pCtx;
+    pCtx->pOldMethod = pFile->pMethod;
+    pFile->pMethod = &proxyIoMethods;
+  }else{
+    if( pCtx->conchFile ){
+      pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile);
+      sqlite3_free(pCtx->conchFile);
+    }
+    sqlite3DbFree(0, pCtx->lockProxyPath);
+    sqlite3_free(pCtx->conchFilePath);
+    sqlite3_free(pCtx);
+  }
+  OSTRACE(("TRANSPROXY  %d %s\n", pFile->h,
+           (rc==SQLITE_OK ? "ok" : "failed")));
+  return rc;
+}
+
+
+/*
+** This routine handles sqlite3_file_control() calls that are specific
+** to proxy locking.
+*/
+static int proxyFileControl(sqlite3_file *id, int op, void *pArg){
+  switch( op ){
+    case SQLITE_FCNTL_GET_LOCKPROXYFILE: {
+      unixFile *pFile = (unixFile*)id;
+      if( pFile->pMethod == &proxyIoMethods ){
+        proxyLockingContext *pCtx = (proxyLockingContext*)pFile->lockingContext;
+        proxyTakeConch(pFile);
+        if( pCtx->lockProxyPath ){
+          *(const char **)pArg = pCtx->lockProxyPath;
+        }else{
+          *(const char **)pArg = ":auto: (not held)";
+        }
+      } else {
+        *(const char **)pArg = NULL;
+      }
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_SET_LOCKPROXYFILE: {
+      unixFile *pFile = (unixFile*)id;
+      int rc = SQLITE_OK;
+      int isProxyStyle = (pFile->pMethod == &proxyIoMethods);
+      if( pArg==NULL || (const char *)pArg==0 ){
+        if( isProxyStyle ){
+          /* turn off proxy locking - not supported.  If support is added for
+          ** switching proxy locking mode off then it will need to fail if
+          ** the journal mode is WAL mode.
+          */
+          rc = SQLITE_ERROR /*SQLITE_PROTOCOL? SQLITE_MISUSE?*/;
+        }else{
+          /* turn off proxy locking - already off - NOOP */
+          rc = SQLITE_OK;
+        }
+      }else{
+        const char *proxyPath = (const char *)pArg;
+        if( isProxyStyle ){
+          proxyLockingContext *pCtx =
+            (proxyLockingContext*)pFile->lockingContext;
+          if( !strcmp(pArg, ":auto:")
+           || (pCtx->lockProxyPath &&
+               !strncmp(pCtx->lockProxyPath, proxyPath, MAXPATHLEN))
+          ){
+            rc = SQLITE_OK;
+          }else{
+            rc = switchLockProxyPath(pFile, proxyPath);
+          }
+        }else{
+          /* turn on proxy file locking */
+          rc = proxyTransformUnixFile(pFile, proxyPath);
+        }
+      }
+      return rc;
+    }
+    default: {
+      assert( 0 );  /* The call assures that only valid opcodes are sent */
+    }
+  }
+  /*NOTREACHED*/ assert(0);
+  return SQLITE_ERROR;
+}
+
+/*
+** Within this division (the proxying locking implementation) the procedures
+** above this point are all utilities.  The lock-related methods of the
+** proxy-locking sqlite3_io_method object follow.
+*/
+
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, set *pResOut
+** to a non-zero value otherwise *pResOut is set to zero.  The return value
+** is set to SQLITE_OK unless an I/O error occurs during lock checking.
+*/
+static int proxyCheckReservedLock(sqlite3_file *id, int *pResOut) {
+  unixFile *pFile = (unixFile*)id;
+  int rc = proxyTakeConch(pFile);
+  if( rc==SQLITE_OK ){
+    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+    if( pCtx->conchHeld>0 ){
+      unixFile *proxy = pCtx->lockProxy;
+      return proxy->pMethod->xCheckReservedLock((sqlite3_file*)proxy, pResOut);
+    }else{ /* conchHeld < 0 is lockless */
+      pResOut=0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Lock the file with the lock specified by parameter eFileLock - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  Use the sqlite3OsUnlock()
+** routine to lower a locking level.
+*/
+static int proxyLock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  int rc = proxyTakeConch(pFile);
+  if( rc==SQLITE_OK ){
+    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+    if( pCtx->conchHeld>0 ){
+      unixFile *proxy = pCtx->lockProxy;
+      rc = proxy->pMethod->xLock((sqlite3_file*)proxy, eFileLock);
+      pFile->eFileLock = proxy->eFileLock;
+    }else{
+      /* conchHeld < 0 is lockless */
+    }
+  }
+  return rc;
+}
+
+
+/*
+** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int proxyUnlock(sqlite3_file *id, int eFileLock) {
+  unixFile *pFile = (unixFile*)id;
+  int rc = proxyTakeConch(pFile);
+  if( rc==SQLITE_OK ){
+    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+    if( pCtx->conchHeld>0 ){
+      unixFile *proxy = pCtx->lockProxy;
+      rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, eFileLock);
+      pFile->eFileLock = proxy->eFileLock;
+    }else{
+      /* conchHeld < 0 is lockless */
+    }
+  }
+  return rc;
+}
+
+/*
+** Close a file that uses proxy locks.
+*/
+static int proxyClose(sqlite3_file *id) {
+  if( ALWAYS(id) ){
+    unixFile *pFile = (unixFile*)id;
+    proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+    unixFile *lockProxy = pCtx->lockProxy;
+    unixFile *conchFile = pCtx->conchFile;
+    int rc = SQLITE_OK;
+
+    if( lockProxy ){
+      rc = lockProxy->pMethod->xUnlock((sqlite3_file*)lockProxy, NO_LOCK);
+      if( rc ) return rc;
+      rc = lockProxy->pMethod->xClose((sqlite3_file*)lockProxy);
+      if( rc ) return rc;
+      sqlite3_free(lockProxy);
+      pCtx->lockProxy = 0;
+    }
+    if( conchFile ){
+      if( pCtx->conchHeld ){
+        rc = proxyReleaseConch(pFile);
+        if( rc ) return rc;
+      }
+      rc = conchFile->pMethod->xClose((sqlite3_file*)conchFile);
+      if( rc ) return rc;
+      sqlite3_free(conchFile);
+    }
+    sqlite3DbFree(0, pCtx->lockProxyPath);
+    sqlite3_free(pCtx->conchFilePath);
+    sqlite3DbFree(0, pCtx->dbPath);
+    /* restore the original locking context and pMethod then close it */
+    pFile->lockingContext = pCtx->oldLockingContext;
+    pFile->pMethod = pCtx->pOldMethod;
+    sqlite3_free(pCtx);
+    return pFile->pMethod->xClose(id);
+  }
+  return SQLITE_OK;
+}
+
+
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+/*
+** The proxy locking style is intended for use with AFP filesystems.
+** And since AFP is only supported on MacOSX, the proxy locking is also
+** restricted to MacOSX.
+**
+**
+******************* End of the proxy lock implementation **********************
+******************************************************************************/
+
+/*
+** Initialize the operating system interface.
+**
+** This routine registers all VFS implementations for unix-like operating
+** systems.  This routine, and the sqlite3_os_end() routine that follows,
+** should be the only routines in this file that are visible from other
+** files.
+**
+** This routine is called once during SQLite initialization and by a
+** single thread.  The memory allocation and mutex subsystems have not
+** necessarily been initialized when this routine is called, and so they
+** should not be used.
+*/
+SQLITE_API int sqlite3_os_init(void){
+  /*
+  ** The following macro defines an initializer for an sqlite3_vfs object.
+  ** The name of the VFS is NAME.  The pAppData is a pointer to a pointer
+  ** to the "finder" function.  (pAppData is a pointer to a pointer because
+  ** silly C90 rules prohibit a void* from being cast to a function pointer
+  ** and so we have to go through the intermediate pointer to avoid problems
+  ** when compiling with -pedantic-errors on GCC.)
+  **
+  ** The FINDER parameter to this macro is the name of the pointer to the
+  ** finder-function.  The finder-function returns a pointer to the
+  ** sqlite_io_methods object that implements the desired locking
+  ** behaviors.  See the division above that contains the IOMETHODS
+  ** macro for addition information on finder-functions.
+  **
+  ** Most finders simply return a pointer to a fixed sqlite3_io_methods
+  ** object.  But the "autolockIoFinder" available on MacOSX does a little
+  ** more than that; it looks at the filesystem type that hosts the
+  ** database file and tries to choose an locking method appropriate for
+  ** that filesystem time.
+  */
+  #define UNIXVFS(VFSNAME, FINDER) {                        \
+    3,                    /* iVersion */                    \
+    sizeof(unixFile),     /* szOsFile */                    \
+    MAX_PATHNAME,         /* mxPathname */                  \
+    0,                    /* pNext */                       \
+    VFSNAME,              /* zName */                       \
+    (void*)&FINDER,       /* pAppData */                    \
+    unixOpen,             /* xOpen */                       \
+    unixDelete,           /* xDelete */                     \
+    unixAccess,           /* xAccess */                     \
+    unixFullPathname,     /* xFullPathname */               \
+    unixDlOpen,           /* xDlOpen */                     \
+    unixDlError,          /* xDlError */                    \
+    unixDlSym,            /* xDlSym */                      \
+    unixDlClose,          /* xDlClose */                    \
+    unixRandomness,       /* xRandomness */                 \
+    unixSleep,            /* xSleep */                      \
+    unixCurrentTime,      /* xCurrentTime */                \
+    unixGetLastError,     /* xGetLastError */               \
+    unixCurrentTimeInt64, /* xCurrentTimeInt64 */           \
+    unixSetSystemCall,    /* xSetSystemCall */              \
+    unixGetSystemCall,    /* xGetSystemCall */              \
+    unixNextSystemCall,   /* xNextSystemCall */             \
+  }
+
+  /*
+  ** All default VFSes for unix are contained in the following array.
+  **
+  ** Note that the sqlite3_vfs.pNext field of the VFS object is modified
+  ** by the SQLite core when the VFS is registered.  So the following
+  ** array cannot be const.
+  */
+  static sqlite3_vfs aVfs[] = {
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+    UNIXVFS("unix",          autolockIoFinder ),
+#elif OS_VXWORKS
+    UNIXVFS("unix",          vxworksIoFinder ),
+#else
+    UNIXVFS("unix",          posixIoFinder ),
+#endif
+    UNIXVFS("unix-none",     nolockIoFinder ),
+    UNIXVFS("unix-dotfile",  dotlockIoFinder ),
+    UNIXVFS("unix-excl",     posixIoFinder ),
+#if OS_VXWORKS
+    UNIXVFS("unix-namedsem", semIoFinder ),
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE || OS_VXWORKS
+    UNIXVFS("unix-posix",    posixIoFinder ),
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE
+    UNIXVFS("unix-flock",    flockIoFinder ),
+#endif
+#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
+    UNIXVFS("unix-afp",      afpIoFinder ),
+    UNIXVFS("unix-nfs",      nfsIoFinder ),
+    UNIXVFS("unix-proxy",    proxyIoFinder ),
+#endif
+  };
+  unsigned int i;          /* Loop counter */
+
+  /* Double-check that the aSyscall[] array has been constructed
+  ** correctly.  See ticket [bb3a86e890c8e96ab] */
+  assert( ArraySize(aSyscall)==29 );
+
+  /* Register all VFSes defined in the aVfs[] array */
+  for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
+#ifdef SQLITE_DEFAULT_UNIX_VFS
+    sqlite3_vfs_register(&aVfs[i],
+           0==strcmp(aVfs[i].zName,SQLITE_DEFAULT_UNIX_VFS));
+#else
+    sqlite3_vfs_register(&aVfs[i], i==0);
+#endif
+  }
+#ifdef SQLITE_OS_KV_OPTIONAL
+  sqlite3KvvfsInit();
+#endif
+  unixBigLock = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
+
+#ifndef SQLITE_OMIT_WAL
+  /* Validate lock assumptions */
+  assert( SQLITE_SHM_NLOCK==8 );  /* Number of available locks */
+  assert( UNIX_SHM_BASE==120  );  /* Start of locking area */
+  /* Locks:
+  **    WRITE       UNIX_SHM_BASE      120
+  **    CKPT        UNIX_SHM_BASE+1    121
+  **    RECOVER     UNIX_SHM_BASE+2    122
+  **    READ-0      UNIX_SHM_BASE+3    123
+  **    READ-1      UNIX_SHM_BASE+4    124
+  **    READ-2      UNIX_SHM_BASE+5    125
+  **    READ-3      UNIX_SHM_BASE+6    126
+  **    READ-4      UNIX_SHM_BASE+7    127
+  **    DMS         UNIX_SHM_BASE+8    128
+  */
+  assert( UNIX_SHM_DMS==128   );  /* Byte offset of the deadman-switch */
+#endif
+
+  /* Initialize temp file dir array. */
+  unixTempFileInit();
+
+  return SQLITE_OK;
+}
+
+/*
+** Shutdown the operating system interface.
+**
+** Some operating systems might need to do some cleanup in this routine,
+** to release dynamically allocated objects.  But not on unix.
+** This routine is a no-op for unix.
+*/
+SQLITE_API int sqlite3_os_end(void){
+  unixBigLock = 0;
+  return SQLITE_OK;
+}
+
+#endif /* SQLITE_OS_UNIX */
+
+/************** End of os_unix.c *********************************************/
+/************** Begin file os_win.c ******************************************/
+/*
+** 2004 May 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code that is specific to Windows.
+*/
+/* #include "sqliteInt.h" */
+#if SQLITE_OS_WIN               /* This file is used for Windows only */
+
+/*
+** Include code that is common to all os_*.c files
+*/
+/* #include "os_common.h" */
+
+/*
+** Include the header file for the Windows VFS.
+*/
+/* #include "os_win.h" */
+
+/*
+** Compiling and using WAL mode requires several APIs that are only
+** available in Windows platforms based on the NT kernel.
+*/
+#if !SQLITE_OS_WINNT && !defined(SQLITE_OMIT_WAL)
+#  error "WAL mode requires support from the Windows NT kernel, compile\
+ with SQLITE_OMIT_WAL."
+#endif
+
+#if !SQLITE_OS_WINNT && SQLITE_MAX_MMAP_SIZE>0
+#  error "Memory mapped files require support from the Windows NT kernel,\
+ compile with SQLITE_MAX_MMAP_SIZE=0."
+#endif
+
+/*
+** Are most of the Win32 ANSI APIs available (i.e. with certain exceptions
+** based on the sub-platform)?
+*/
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && !defined(SQLITE_WIN32_NO_ANSI)
+#  define SQLITE_WIN32_HAS_ANSI
+#endif
+
+/*
+** Are most of the Win32 Unicode APIs available (i.e. with certain exceptions
+** based on the sub-platform)?
+*/
+#if (SQLITE_OS_WINCE || SQLITE_OS_WINNT || SQLITE_OS_WINRT) && \
+    !defined(SQLITE_WIN32_NO_WIDE)
+#  define SQLITE_WIN32_HAS_WIDE
+#endif
+
+/*
+** Make sure at least one set of Win32 APIs is available.
+*/
+#if !defined(SQLITE_WIN32_HAS_ANSI) && !defined(SQLITE_WIN32_HAS_WIDE)
+#  error "At least one of SQLITE_WIN32_HAS_ANSI and SQLITE_WIN32_HAS_WIDE\
+ must be defined."
+#endif
+
+/*
+** Define the required Windows SDK version constants if they are not
+** already available.
+*/
+#ifndef NTDDI_WIN8
+#  define NTDDI_WIN8                        0x06020000
+#endif
+
+#ifndef NTDDI_WINBLUE
+#  define NTDDI_WINBLUE                     0x06030000
+#endif
+
+#ifndef NTDDI_WINTHRESHOLD
+#  define NTDDI_WINTHRESHOLD                0x06040000
+#endif
+
+/*
+** Check to see if the GetVersionEx[AW] functions are deprecated on the
+** target system.  GetVersionEx was first deprecated in Win8.1.
+*/
+#ifndef SQLITE_WIN32_GETVERSIONEX
+#  if defined(NTDDI_VERSION) && NTDDI_VERSION >= NTDDI_WINBLUE
+#    define SQLITE_WIN32_GETVERSIONEX   0   /* GetVersionEx() is deprecated */
+#  else
+#    define SQLITE_WIN32_GETVERSIONEX   1   /* GetVersionEx() is current */
+#  endif
+#endif
+
+/*
+** Check to see if the CreateFileMappingA function is supported on the
+** target system.  It is unavailable when using "mincore.lib" on Win10.
+** When compiling for Windows 10, always assume "mincore.lib" is in use.
+*/
+#ifndef SQLITE_WIN32_CREATEFILEMAPPINGA
+#  if defined(NTDDI_VERSION) && NTDDI_VERSION >= NTDDI_WINTHRESHOLD
+#    define SQLITE_WIN32_CREATEFILEMAPPINGA   0
+#  else
+#    define SQLITE_WIN32_CREATEFILEMAPPINGA   1
+#  endif
+#endif
+
+/*
+** This constant should already be defined (in the "WinDef.h" SDK file).
+*/
+#ifndef MAX_PATH
+#  define MAX_PATH                      (260)
+#endif
+
+/*
+** Maximum pathname length (in chars) for Win32.  This should normally be
+** MAX_PATH.
+*/
+#ifndef SQLITE_WIN32_MAX_PATH_CHARS
+#  define SQLITE_WIN32_MAX_PATH_CHARS   (MAX_PATH)
+#endif
+
+/*
+** This constant should already be defined (in the "WinNT.h" SDK file).
+*/
+#ifndef UNICODE_STRING_MAX_CHARS
+#  define UNICODE_STRING_MAX_CHARS      (32767)
+#endif
+
+/*
+** Maximum pathname length (in chars) for WinNT.  This should normally be
+** UNICODE_STRING_MAX_CHARS.
+*/
+#ifndef SQLITE_WINNT_MAX_PATH_CHARS
+#  define SQLITE_WINNT_MAX_PATH_CHARS   (UNICODE_STRING_MAX_CHARS)
+#endif
+
+/*
+** Maximum pathname length (in bytes) for Win32.  The MAX_PATH macro is in
+** characters, so we allocate 4 bytes per character assuming worst-case of
+** 4-bytes-per-character for UTF8.
+*/
+#ifndef SQLITE_WIN32_MAX_PATH_BYTES
+#  define SQLITE_WIN32_MAX_PATH_BYTES   (SQLITE_WIN32_MAX_PATH_CHARS*4)
+#endif
+
+/*
+** Maximum pathname length (in bytes) for WinNT.  This should normally be
+** UNICODE_STRING_MAX_CHARS * sizeof(WCHAR).
+*/
+#ifndef SQLITE_WINNT_MAX_PATH_BYTES
+#  define SQLITE_WINNT_MAX_PATH_BYTES   \
+                            (sizeof(WCHAR) * SQLITE_WINNT_MAX_PATH_CHARS)
+#endif
+
+/*
+** Maximum error message length (in chars) for WinRT.
+*/
+#ifndef SQLITE_WIN32_MAX_ERRMSG_CHARS
+#  define SQLITE_WIN32_MAX_ERRMSG_CHARS (1024)
+#endif
+
+/*
+** Returns non-zero if the character should be treated as a directory
+** separator.
+*/
+#ifndef winIsDirSep
+#  define winIsDirSep(a)                (((a) == '/') || ((a) == '\\'))
+#endif
+
+/*
+** This macro is used when a local variable is set to a value that is
+** [sometimes] not used by the code (e.g. via conditional compilation).
+*/
+#ifndef UNUSED_VARIABLE_VALUE
+#  define UNUSED_VARIABLE_VALUE(x)      (void)(x)
+#endif
+
+/*
+** Returns the character that should be used as the directory separator.
+*/
+#ifndef winGetDirSep
+#  define winGetDirSep()                '\\'
+#endif
+
+/*
+** Do we need to manually define the Win32 file mapping APIs for use with WAL
+** mode or memory mapped files (e.g. these APIs are available in the Windows
+** CE SDK; however, they are not present in the header file)?
+*/
+#if SQLITE_WIN32_FILEMAPPING_API && \
+        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
+/*
+** Two of the file mapping APIs are different under WinRT.  Figure out which
+** set we need.
+*/
+#if SQLITE_OS_WINRT
+WINBASEAPI HANDLE WINAPI CreateFileMappingFromApp(HANDLE, \
+        LPSECURITY_ATTRIBUTES, ULONG, ULONG64, LPCWSTR);
+
+WINBASEAPI LPVOID WINAPI MapViewOfFileFromApp(HANDLE, ULONG, ULONG64, SIZE_T);
+#else
+#if defined(SQLITE_WIN32_HAS_ANSI)
+WINBASEAPI HANDLE WINAPI CreateFileMappingA(HANDLE, LPSECURITY_ATTRIBUTES, \
+        DWORD, DWORD, DWORD, LPCSTR);
+#endif /* defined(SQLITE_WIN32_HAS_ANSI) */
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+WINBASEAPI HANDLE WINAPI CreateFileMappingW(HANDLE, LPSECURITY_ATTRIBUTES, \
+        DWORD, DWORD, DWORD, LPCWSTR);
+#endif /* defined(SQLITE_WIN32_HAS_WIDE) */
+
+WINBASEAPI LPVOID WINAPI MapViewOfFile(HANDLE, DWORD, DWORD, DWORD, SIZE_T);
+#endif /* SQLITE_OS_WINRT */
+
+/*
+** These file mapping APIs are common to both Win32 and WinRT.
+*/
+
+WINBASEAPI BOOL WINAPI FlushViewOfFile(LPCVOID, SIZE_T);
+WINBASEAPI BOOL WINAPI UnmapViewOfFile(LPCVOID);
+#endif /* SQLITE_WIN32_FILEMAPPING_API */
+
+/*
+** Some Microsoft compilers lack this definition.
+*/
+#ifndef INVALID_FILE_ATTRIBUTES
+# define INVALID_FILE_ATTRIBUTES ((DWORD)-1)
+#endif
+
+#ifndef FILE_FLAG_MASK
+# define FILE_FLAG_MASK          (0xFF3C0000)
+#endif
+
+#ifndef FILE_ATTRIBUTE_MASK
+# define FILE_ATTRIBUTE_MASK     (0x0003FFF7)
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+/* Forward references to structures used for WAL */
+typedef struct winShm winShm;           /* A connection to shared-memory */
+typedef struct winShmNode winShmNode;   /* A region of shared-memory */
+#endif
+
+/*
+** WinCE lacks native support for file locking so we have to fake it
+** with some code of our own.
+*/
+#if SQLITE_OS_WINCE
+typedef struct winceLock {
+  int nReaders;       /* Number of reader locks obtained */
+  BOOL bPending;      /* Indicates a pending lock has been obtained */
+  BOOL bReserved;     /* Indicates a reserved lock has been obtained */
+  BOOL bExclusive;    /* Indicates an exclusive lock has been obtained */
+} winceLock;
+#endif
+
+/*
+** The winFile structure is a subclass of sqlite3_file* specific to the win32
+** portability layer.
+*/
+typedef struct winFile winFile;
+struct winFile {
+  const sqlite3_io_methods *pMethod; /*** Must be first ***/
+  sqlite3_vfs *pVfs;      /* The VFS used to open this file */
+  HANDLE h;               /* Handle for accessing the file */
+  u8 locktype;            /* Type of lock currently held on this file */
+  short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
+  u8 ctrlFlags;           /* Flags.  See WINFILE_* below */
+  DWORD lastErrno;        /* The Windows errno from the last I/O error */
+#ifndef SQLITE_OMIT_WAL
+  winShm *pShm;           /* Instance of shared memory on this file */
+#endif
+  const char *zPath;      /* Full pathname of this file */
+  int szChunk;            /* Chunk size configured by FCNTL_CHUNK_SIZE */
+#if SQLITE_OS_WINCE
+  LPWSTR zDeleteOnClose;  /* Name of file to delete when closing */
+  HANDLE hMutex;          /* Mutex used to control access to shared lock */
+  HANDLE hShared;         /* Shared memory segment used for locking */
+  winceLock local;        /* Locks obtained by this instance of winFile */
+  winceLock *shared;      /* Global shared lock memory for the file  */
+#endif
+#if SQLITE_MAX_MMAP_SIZE>0
+  int nFetchOut;                /* Number of outstanding xFetch references */
+  HANDLE hMap;                  /* Handle for accessing memory mapping */
+  void *pMapRegion;             /* Area memory mapped */
+  sqlite3_int64 mmapSize;       /* Size of mapped region */
+  sqlite3_int64 mmapSizeMax;    /* Configured FCNTL_MMAP_SIZE value */
+#endif
+};
+
+/*
+** The winVfsAppData structure is used for the pAppData member for all of the
+** Win32 VFS variants.
+*/
+typedef struct winVfsAppData winVfsAppData;
+struct winVfsAppData {
+  const sqlite3_io_methods *pMethod; /* The file I/O methods to use. */
+  void *pAppData;                    /* The extra pAppData, if any. */
+  BOOL bNoLock;                      /* Non-zero if locking is disabled. */
+};
+
+/*
+** Allowed values for winFile.ctrlFlags
+*/
+#define WINFILE_RDONLY          0x02   /* Connection is read only */
+#define WINFILE_PERSIST_WAL     0x04   /* Persistent WAL mode */
+#define WINFILE_PSOW            0x10   /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
+
+/*
+ * The size of the buffer used by sqlite3_win32_write_debug().
+ */
+#ifndef SQLITE_WIN32_DBG_BUF_SIZE
+#  define SQLITE_WIN32_DBG_BUF_SIZE   ((int)(4096-sizeof(DWORD)))
+#endif
+
+/*
+ * If compiled with SQLITE_WIN32_MALLOC on Windows, we will use the
+ * various Win32 API heap functions instead of our own.
+ */
+#ifdef SQLITE_WIN32_MALLOC
+
+/*
+ * If this is non-zero, an isolated heap will be created by the native Win32
+ * allocator subsystem; otherwise, the default process heap will be used.  This
+ * setting has no effect when compiling for WinRT.  By default, this is enabled
+ * and an isolated heap will be created to store all allocated data.
+ *
+ ******************************************************************************
+ * WARNING: It is important to note that when this setting is non-zero and the
+ *          winMemShutdown function is called (e.g. by the sqlite3_shutdown
+ *          function), all data that was allocated using the isolated heap will
+ *          be freed immediately and any attempt to access any of that freed
+ *          data will almost certainly result in an immediate access violation.
+ ******************************************************************************
+ */
+#ifndef SQLITE_WIN32_HEAP_CREATE
+#  define SQLITE_WIN32_HEAP_CREATE        (TRUE)
+#endif
+
+/*
+ * This is the maximum possible initial size of the Win32-specific heap, in
+ * bytes.
+ */
+#ifndef SQLITE_WIN32_HEAP_MAX_INIT_SIZE
+#  define SQLITE_WIN32_HEAP_MAX_INIT_SIZE (4294967295U)
+#endif
+
+/*
+ * This is the extra space for the initial size of the Win32-specific heap,
+ * in bytes.  This value may be zero.
+ */
+#ifndef SQLITE_WIN32_HEAP_INIT_EXTRA
+#  define SQLITE_WIN32_HEAP_INIT_EXTRA  (4194304)
+#endif
+
+/*
+ * Calculate the maximum legal cache size, in pages, based on the maximum
+ * possible initial heap size and the default page size, setting aside the
+ * needed extra space.
+ */
+#ifndef SQLITE_WIN32_MAX_CACHE_SIZE
+#  define SQLITE_WIN32_MAX_CACHE_SIZE   (((SQLITE_WIN32_HEAP_MAX_INIT_SIZE) - \
+                                          (SQLITE_WIN32_HEAP_INIT_EXTRA)) / \
+                                         (SQLITE_DEFAULT_PAGE_SIZE))
+#endif
+
+/*
+ * This is cache size used in the calculation of the initial size of the
+ * Win32-specific heap.  It cannot be negative.
+ */
+#ifndef SQLITE_WIN32_CACHE_SIZE
+#  if SQLITE_DEFAULT_CACHE_SIZE>=0
+#    define SQLITE_WIN32_CACHE_SIZE     (SQLITE_DEFAULT_CACHE_SIZE)
+#  else
+#    define SQLITE_WIN32_CACHE_SIZE     (-(SQLITE_DEFAULT_CACHE_SIZE))
+#  endif
+#endif
+
+/*
+ * Make sure that the calculated cache size, in pages, cannot cause the
+ * initial size of the Win32-specific heap to exceed the maximum amount
+ * of memory that can be specified in the call to HeapCreate.
+ */
+#if SQLITE_WIN32_CACHE_SIZE>SQLITE_WIN32_MAX_CACHE_SIZE
+#  undef SQLITE_WIN32_CACHE_SIZE
+#  define SQLITE_WIN32_CACHE_SIZE       (2000)
+#endif
+
+/*
+ * The initial size of the Win32-specific heap.  This value may be zero.
+ */
+#ifndef SQLITE_WIN32_HEAP_INIT_SIZE
+#  define SQLITE_WIN32_HEAP_INIT_SIZE   ((SQLITE_WIN32_CACHE_SIZE) * \
+                                         (SQLITE_DEFAULT_PAGE_SIZE) + \
+                                         (SQLITE_WIN32_HEAP_INIT_EXTRA))
+#endif
+
+/*
+ * The maximum size of the Win32-specific heap.  This value may be zero.
+ */
+#ifndef SQLITE_WIN32_HEAP_MAX_SIZE
+#  define SQLITE_WIN32_HEAP_MAX_SIZE    (0)
+#endif
+
+/*
+ * The extra flags to use in calls to the Win32 heap APIs.  This value may be
+ * zero for the default behavior.
+ */
+#ifndef SQLITE_WIN32_HEAP_FLAGS
+#  define SQLITE_WIN32_HEAP_FLAGS       (0)
+#endif
+
+
+/*
+** The winMemData structure stores information required by the Win32-specific
+** sqlite3_mem_methods implementation.
+*/
+typedef struct winMemData winMemData;
+struct winMemData {
+#ifndef NDEBUG
+  u32 magic1;   /* Magic number to detect structure corruption. */
+#endif
+  HANDLE hHeap; /* The handle to our heap. */
+  BOOL bOwned;  /* Do we own the heap (i.e. destroy it on shutdown)? */
+#ifndef NDEBUG
+  u32 magic2;   /* Magic number to detect structure corruption. */
+#endif
+};
+
+#ifndef NDEBUG
+#define WINMEM_MAGIC1     0x42b2830b
+#define WINMEM_MAGIC2     0xbd4d7cf4
+#endif
+
+static struct winMemData win_mem_data = {
+#ifndef NDEBUG
+  WINMEM_MAGIC1,
+#endif
+  NULL, FALSE
+#ifndef NDEBUG
+  ,WINMEM_MAGIC2
+#endif
+};
+
+#ifndef NDEBUG
+#define winMemAssertMagic1() assert( win_mem_data.magic1==WINMEM_MAGIC1 )
+#define winMemAssertMagic2() assert( win_mem_data.magic2==WINMEM_MAGIC2 )
+#define winMemAssertMagic()  winMemAssertMagic1(); winMemAssertMagic2();
+#else
+#define winMemAssertMagic()
+#endif
+
+#define winMemGetDataPtr()  &win_mem_data
+#define winMemGetHeap()     win_mem_data.hHeap
+#define winMemGetOwned()    win_mem_data.bOwned
+
+static void *winMemMalloc(int nBytes);
+static void winMemFree(void *pPrior);
+static void *winMemRealloc(void *pPrior, int nBytes);
+static int winMemSize(void *p);
+static int winMemRoundup(int n);
+static int winMemInit(void *pAppData);
+static void winMemShutdown(void *pAppData);
+
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetWin32(void);
+#endif /* SQLITE_WIN32_MALLOC */
+
+/*
+** The following variable is (normally) set once and never changes
+** thereafter.  It records whether the operating system is Win9x
+** or WinNT.
+**
+** 0:   Operating system unknown.
+** 1:   Operating system is Win9x.
+** 2:   Operating system is WinNT.
+**
+** In order to facilitate testing on a WinNT system, the test fixture
+** can manually set this value to 1 to emulate Win98 behavior.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API LONG SQLITE_WIN32_VOLATILE sqlite3_os_type = 0;
+#else
+static LONG SQLITE_WIN32_VOLATILE sqlite3_os_type = 0;
+#endif
+
+#ifndef SYSCALL
+#  define SYSCALL sqlite3_syscall_ptr
+#endif
+
+/*
+** This function is not available on Windows CE or WinRT.
+ */
+
+#if SQLITE_OS_WINCE || SQLITE_OS_WINRT
+#  define osAreFileApisANSI()       1
+#endif
+
+/*
+** Many system calls are accessed through pointer-to-functions so that
+** they may be overridden at runtime to facilitate fault injection during
+** testing and sandboxing.  The following array holds the names and pointers
+** to all overrideable system calls.
+*/
+static struct win_syscall {
+  const char *zName;            /* Name of the system call */
+  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
+  sqlite3_syscall_ptr pDefault; /* Default value */
+} aSyscall[] = {
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "AreFileApisANSI",         (SYSCALL)AreFileApisANSI,         0 },
+#else
+  { "AreFileApisANSI",         (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osAreFileApisANSI
+#define osAreFileApisANSI ((BOOL(WINAPI*)(VOID))aSyscall[0].pCurrent)
+#endif
+
+#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CharLowerW",              (SYSCALL)CharLowerW,              0 },
+#else
+  { "CharLowerW",              (SYSCALL)0,                       0 },
+#endif
+
+#define osCharLowerW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[1].pCurrent)
+
+#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CharUpperW",              (SYSCALL)CharUpperW,              0 },
+#else
+  { "CharUpperW",              (SYSCALL)0,                       0 },
+#endif
+
+#define osCharUpperW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[2].pCurrent)
+
+  { "CloseHandle",             (SYSCALL)CloseHandle,             0 },
+
+#define osCloseHandle ((BOOL(WINAPI*)(HANDLE))aSyscall[3].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "CreateFileA",             (SYSCALL)CreateFileA,             0 },
+#else
+  { "CreateFileA",             (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileA ((HANDLE(WINAPI*)(LPCSTR,DWORD,DWORD, \
+        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[4].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CreateFileW",             (SYSCALL)CreateFileW,             0 },
+#else
+  { "CreateFileW",             (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileW ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD, \
+        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[5].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_ANSI) && \
+        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0) && \
+        SQLITE_WIN32_CREATEFILEMAPPINGA
+  { "CreateFileMappingA",      (SYSCALL)CreateFileMappingA,      0 },
+#else
+  { "CreateFileMappingA",      (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileMappingA ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
+        DWORD,DWORD,DWORD,LPCSTR))aSyscall[6].pCurrent)
+
+#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
+        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0))
+  { "CreateFileMappingW",      (SYSCALL)CreateFileMappingW,      0 },
+#else
+  { "CreateFileMappingW",      (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFileMappingW ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
+        DWORD,DWORD,DWORD,LPCWSTR))aSyscall[7].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "CreateMutexW",            (SYSCALL)CreateMutexW,            0 },
+#else
+  { "CreateMutexW",            (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateMutexW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,BOOL, \
+        LPCWSTR))aSyscall[8].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "DeleteFileA",             (SYSCALL)DeleteFileA,             0 },
+#else
+  { "DeleteFileA",             (SYSCALL)0,                       0 },
+#endif
+
+#define osDeleteFileA ((BOOL(WINAPI*)(LPCSTR))aSyscall[9].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "DeleteFileW",             (SYSCALL)DeleteFileW,             0 },
+#else
+  { "DeleteFileW",             (SYSCALL)0,                       0 },
+#endif
+
+#define osDeleteFileW ((BOOL(WINAPI*)(LPCWSTR))aSyscall[10].pCurrent)
+
+#if SQLITE_OS_WINCE
+  { "FileTimeToLocalFileTime", (SYSCALL)FileTimeToLocalFileTime, 0 },
+#else
+  { "FileTimeToLocalFileTime", (SYSCALL)0,                       0 },
+#endif
+
+#define osFileTimeToLocalFileTime ((BOOL(WINAPI*)(CONST FILETIME*, \
+        LPFILETIME))aSyscall[11].pCurrent)
+
+#if SQLITE_OS_WINCE
+  { "FileTimeToSystemTime",    (SYSCALL)FileTimeToSystemTime,    0 },
+#else
+  { "FileTimeToSystemTime",    (SYSCALL)0,                       0 },
+#endif
+
+#define osFileTimeToSystemTime ((BOOL(WINAPI*)(CONST FILETIME*, \
+        LPSYSTEMTIME))aSyscall[12].pCurrent)
+
+  { "FlushFileBuffers",        (SYSCALL)FlushFileBuffers,        0 },
+
+#define osFlushFileBuffers ((BOOL(WINAPI*)(HANDLE))aSyscall[13].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "FormatMessageA",          (SYSCALL)FormatMessageA,          0 },
+#else
+  { "FormatMessageA",          (SYSCALL)0,                       0 },
+#endif
+
+#define osFormatMessageA ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPSTR, \
+        DWORD,va_list*))aSyscall[14].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "FormatMessageW",          (SYSCALL)FormatMessageW,          0 },
+#else
+  { "FormatMessageW",          (SYSCALL)0,                       0 },
+#endif
+
+#define osFormatMessageW ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPWSTR, \
+        DWORD,va_list*))aSyscall[15].pCurrent)
+
+#if !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  { "FreeLibrary",             (SYSCALL)FreeLibrary,             0 },
+#else
+  { "FreeLibrary",             (SYSCALL)0,                       0 },
+#endif
+
+#define osFreeLibrary ((BOOL(WINAPI*)(HMODULE))aSyscall[16].pCurrent)
+
+  { "GetCurrentProcessId",     (SYSCALL)GetCurrentProcessId,     0 },
+
+#define osGetCurrentProcessId ((DWORD(WINAPI*)(VOID))aSyscall[17].pCurrent)
+
+#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetDiskFreeSpaceA",       (SYSCALL)GetDiskFreeSpaceA,       0 },
+#else
+  { "GetDiskFreeSpaceA",       (SYSCALL)0,                       0 },
+#endif
+
+#define osGetDiskFreeSpaceA ((BOOL(WINAPI*)(LPCSTR,LPDWORD,LPDWORD,LPDWORD, \
+        LPDWORD))aSyscall[18].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetDiskFreeSpaceW",       (SYSCALL)GetDiskFreeSpaceW,       0 },
+#else
+  { "GetDiskFreeSpaceW",       (SYSCALL)0,                       0 },
+#endif
+
+#define osGetDiskFreeSpaceW ((BOOL(WINAPI*)(LPCWSTR,LPDWORD,LPDWORD,LPDWORD, \
+        LPDWORD))aSyscall[19].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetFileAttributesA",      (SYSCALL)GetFileAttributesA,      0 },
+#else
+  { "GetFileAttributesA",      (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileAttributesA ((DWORD(WINAPI*)(LPCSTR))aSyscall[20].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetFileAttributesW",      (SYSCALL)GetFileAttributesW,      0 },
+#else
+  { "GetFileAttributesW",      (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileAttributesW ((DWORD(WINAPI*)(LPCWSTR))aSyscall[21].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetFileAttributesExW",    (SYSCALL)GetFileAttributesExW,    0 },
+#else
+  { "GetFileAttributesExW",    (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileAttributesExW ((BOOL(WINAPI*)(LPCWSTR,GET_FILEEX_INFO_LEVELS, \
+        LPVOID))aSyscall[22].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "GetFileSize",             (SYSCALL)GetFileSize,             0 },
+#else
+  { "GetFileSize",             (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFileSize ((DWORD(WINAPI*)(HANDLE,LPDWORD))aSyscall[23].pCurrent)
+
+#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetFullPathNameA",        (SYSCALL)GetFullPathNameA,        0 },
+#else
+  { "GetFullPathNameA",        (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFullPathNameA ((DWORD(WINAPI*)(LPCSTR,DWORD,LPSTR, \
+        LPSTR*))aSyscall[24].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetFullPathNameW",        (SYSCALL)GetFullPathNameW,        0 },
+#else
+  { "GetFullPathNameW",        (SYSCALL)0,                       0 },
+#endif
+
+#define osGetFullPathNameW ((DWORD(WINAPI*)(LPCWSTR,DWORD,LPWSTR, \
+        LPWSTR*))aSyscall[25].pCurrent)
+
+  { "GetLastError",            (SYSCALL)GetLastError,            0 },
+
+#define osGetLastError ((DWORD(WINAPI*)(VOID))aSyscall[26].pCurrent)
+
+#if !defined(SQLITE_OMIT_LOAD_EXTENSION)
+#if SQLITE_OS_WINCE
+  /* The GetProcAddressA() routine is only available on Windows CE. */
+  { "GetProcAddressA",         (SYSCALL)GetProcAddressA,         0 },
+#else
+  /* All other Windows platforms expect GetProcAddress() to take
+  ** an ANSI string regardless of the _UNICODE setting */
+  { "GetProcAddressA",         (SYSCALL)GetProcAddress,          0 },
+#endif
+#else
+  { "GetProcAddressA",         (SYSCALL)0,                       0 },
+#endif
+
+#define osGetProcAddressA ((FARPROC(WINAPI*)(HMODULE, \
+        LPCSTR))aSyscall[27].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "GetSystemInfo",           (SYSCALL)GetSystemInfo,           0 },
+#else
+  { "GetSystemInfo",           (SYSCALL)0,                       0 },
+#endif
+
+#define osGetSystemInfo ((VOID(WINAPI*)(LPSYSTEM_INFO))aSyscall[28].pCurrent)
+
+  { "GetSystemTime",           (SYSCALL)GetSystemTime,           0 },
+
+#define osGetSystemTime ((VOID(WINAPI*)(LPSYSTEMTIME))aSyscall[29].pCurrent)
+
+#if !SQLITE_OS_WINCE
+  { "GetSystemTimeAsFileTime", (SYSCALL)GetSystemTimeAsFileTime, 0 },
+#else
+  { "GetSystemTimeAsFileTime", (SYSCALL)0,                       0 },
+#endif
+
+#define osGetSystemTimeAsFileTime ((VOID(WINAPI*)( \
+        LPFILETIME))aSyscall[30].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "GetTempPathA",            (SYSCALL)GetTempPathA,            0 },
+#else
+  { "GetTempPathA",            (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTempPathA ((DWORD(WINAPI*)(DWORD,LPSTR))aSyscall[31].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE)
+  { "GetTempPathW",            (SYSCALL)GetTempPathW,            0 },
+#else
+  { "GetTempPathW",            (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTempPathW ((DWORD(WINAPI*)(DWORD,LPWSTR))aSyscall[32].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "GetTickCount",            (SYSCALL)GetTickCount,            0 },
+#else
+  { "GetTickCount",            (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTickCount ((DWORD(WINAPI*)(VOID))aSyscall[33].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI) && SQLITE_WIN32_GETVERSIONEX
+  { "GetVersionExA",           (SYSCALL)GetVersionExA,           0 },
+#else
+  { "GetVersionExA",           (SYSCALL)0,                       0 },
+#endif
+
+#define osGetVersionExA ((BOOL(WINAPI*)( \
+        LPOSVERSIONINFOA))aSyscall[34].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
+        SQLITE_WIN32_GETVERSIONEX
+  { "GetVersionExW",           (SYSCALL)GetVersionExW,           0 },
+#else
+  { "GetVersionExW",           (SYSCALL)0,                       0 },
+#endif
+
+#define osGetVersionExW ((BOOL(WINAPI*)( \
+        LPOSVERSIONINFOW))aSyscall[35].pCurrent)
+
+  { "HeapAlloc",               (SYSCALL)HeapAlloc,               0 },
+
+#define osHeapAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD, \
+        SIZE_T))aSyscall[36].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "HeapCreate",              (SYSCALL)HeapCreate,              0 },
+#else
+  { "HeapCreate",              (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapCreate ((HANDLE(WINAPI*)(DWORD,SIZE_T, \
+        SIZE_T))aSyscall[37].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "HeapDestroy",             (SYSCALL)HeapDestroy,             0 },
+#else
+  { "HeapDestroy",             (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapDestroy ((BOOL(WINAPI*)(HANDLE))aSyscall[38].pCurrent)
+
+  { "HeapFree",                (SYSCALL)HeapFree,                0 },
+
+#define osHeapFree ((BOOL(WINAPI*)(HANDLE,DWORD,LPVOID))aSyscall[39].pCurrent)
+
+  { "HeapReAlloc",             (SYSCALL)HeapReAlloc,             0 },
+
+#define osHeapReAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD,LPVOID, \
+        SIZE_T))aSyscall[40].pCurrent)
+
+  { "HeapSize",                (SYSCALL)HeapSize,                0 },
+
+#define osHeapSize ((SIZE_T(WINAPI*)(HANDLE,DWORD, \
+        LPCVOID))aSyscall[41].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "HeapValidate",            (SYSCALL)HeapValidate,            0 },
+#else
+  { "HeapValidate",            (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapValidate ((BOOL(WINAPI*)(HANDLE,DWORD, \
+        LPCVOID))aSyscall[42].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "HeapCompact",             (SYSCALL)HeapCompact,             0 },
+#else
+  { "HeapCompact",             (SYSCALL)0,                       0 },
+#endif
+
+#define osHeapCompact ((UINT(WINAPI*)(HANDLE,DWORD))aSyscall[43].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  { "LoadLibraryA",            (SYSCALL)LoadLibraryA,            0 },
+#else
+  { "LoadLibraryA",            (SYSCALL)0,                       0 },
+#endif
+
+#define osLoadLibraryA ((HMODULE(WINAPI*)(LPCSTR))aSyscall[44].pCurrent)
+
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_HAS_WIDE) && \
+        !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  { "LoadLibraryW",            (SYSCALL)LoadLibraryW,            0 },
+#else
+  { "LoadLibraryW",            (SYSCALL)0,                       0 },
+#endif
+
+#define osLoadLibraryW ((HMODULE(WINAPI*)(LPCWSTR))aSyscall[45].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "LocalFree",               (SYSCALL)LocalFree,               0 },
+#else
+  { "LocalFree",               (SYSCALL)0,                       0 },
+#endif
+
+#define osLocalFree ((HLOCAL(WINAPI*)(HLOCAL))aSyscall[46].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "LockFile",                (SYSCALL)LockFile,                0 },
+#else
+  { "LockFile",                (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osLockFile
+#define osLockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        DWORD))aSyscall[47].pCurrent)
+#endif
+
+#if !SQLITE_OS_WINCE
+  { "LockFileEx",              (SYSCALL)LockFileEx,              0 },
+#else
+  { "LockFileEx",              (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osLockFileEx
+#define osLockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD,DWORD, \
+        LPOVERLAPPED))aSyscall[48].pCurrent)
+#endif
+
+#if SQLITE_OS_WINCE || (!SQLITE_OS_WINRT && \
+        (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0))
+  { "MapViewOfFile",           (SYSCALL)MapViewOfFile,           0 },
+#else
+  { "MapViewOfFile",           (SYSCALL)0,                       0 },
+#endif
+
+#define osMapViewOfFile ((LPVOID(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        SIZE_T))aSyscall[49].pCurrent)
+
+  { "MultiByteToWideChar",     (SYSCALL)MultiByteToWideChar,     0 },
+
+#define osMultiByteToWideChar ((int(WINAPI*)(UINT,DWORD,LPCSTR,int,LPWSTR, \
+        int))aSyscall[50].pCurrent)
+
+  { "QueryPerformanceCounter", (SYSCALL)QueryPerformanceCounter, 0 },
+
+#define osQueryPerformanceCounter ((BOOL(WINAPI*)( \
+        LARGE_INTEGER*))aSyscall[51].pCurrent)
+
+  { "ReadFile",                (SYSCALL)ReadFile,                0 },
+
+#define osReadFile ((BOOL(WINAPI*)(HANDLE,LPVOID,DWORD,LPDWORD, \
+        LPOVERLAPPED))aSyscall[52].pCurrent)
+
+  { "SetEndOfFile",            (SYSCALL)SetEndOfFile,            0 },
+
+#define osSetEndOfFile ((BOOL(WINAPI*)(HANDLE))aSyscall[53].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "SetFilePointer",          (SYSCALL)SetFilePointer,          0 },
+#else
+  { "SetFilePointer",          (SYSCALL)0,                       0 },
+#endif
+
+#define osSetFilePointer ((DWORD(WINAPI*)(HANDLE,LONG,PLONG, \
+        DWORD))aSyscall[54].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "Sleep",                   (SYSCALL)Sleep,                   0 },
+#else
+  { "Sleep",                   (SYSCALL)0,                       0 },
+#endif
+
+#define osSleep ((VOID(WINAPI*)(DWORD))aSyscall[55].pCurrent)
+
+  { "SystemTimeToFileTime",    (SYSCALL)SystemTimeToFileTime,    0 },
+
+#define osSystemTimeToFileTime ((BOOL(WINAPI*)(CONST SYSTEMTIME*, \
+        LPFILETIME))aSyscall[56].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  { "UnlockFile",              (SYSCALL)UnlockFile,              0 },
+#else
+  { "UnlockFile",              (SYSCALL)0,                       0 },
+#endif
+
+#ifndef osUnlockFile
+#define osUnlockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        DWORD))aSyscall[57].pCurrent)
+#endif
+
+#if !SQLITE_OS_WINCE
+  { "UnlockFileEx",            (SYSCALL)UnlockFileEx,            0 },
+#else
+  { "UnlockFileEx",            (SYSCALL)0,                       0 },
+#endif
+
+#define osUnlockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
+        LPOVERLAPPED))aSyscall[58].pCurrent)
+
+#if SQLITE_OS_WINCE || !defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0
+  { "UnmapViewOfFile",         (SYSCALL)UnmapViewOfFile,         0 },
+#else
+  { "UnmapViewOfFile",         (SYSCALL)0,                       0 },
+#endif
+
+#define osUnmapViewOfFile ((BOOL(WINAPI*)(LPCVOID))aSyscall[59].pCurrent)
+
+  { "WideCharToMultiByte",     (SYSCALL)WideCharToMultiByte,     0 },
+
+#define osWideCharToMultiByte ((int(WINAPI*)(UINT,DWORD,LPCWSTR,int,LPSTR,int, \
+        LPCSTR,LPBOOL))aSyscall[60].pCurrent)
+
+  { "WriteFile",               (SYSCALL)WriteFile,               0 },
+
+#define osWriteFile ((BOOL(WINAPI*)(HANDLE,LPCVOID,DWORD,LPDWORD, \
+        LPOVERLAPPED))aSyscall[61].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "CreateEventExW",          (SYSCALL)CreateEventExW,          0 },
+#else
+  { "CreateEventExW",          (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateEventExW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,LPCWSTR, \
+        DWORD,DWORD))aSyscall[62].pCurrent)
+
+#if !SQLITE_OS_WINRT
+  { "WaitForSingleObject",     (SYSCALL)WaitForSingleObject,     0 },
+#else
+  { "WaitForSingleObject",     (SYSCALL)0,                       0 },
+#endif
+
+#define osWaitForSingleObject ((DWORD(WINAPI*)(HANDLE, \
+        DWORD))aSyscall[63].pCurrent)
+
+#if !SQLITE_OS_WINCE
+  { "WaitForSingleObjectEx",   (SYSCALL)WaitForSingleObjectEx,   0 },
+#else
+  { "WaitForSingleObjectEx",   (SYSCALL)0,                       0 },
+#endif
+
+#define osWaitForSingleObjectEx ((DWORD(WINAPI*)(HANDLE,DWORD, \
+        BOOL))aSyscall[64].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "SetFilePointerEx",        (SYSCALL)SetFilePointerEx,        0 },
+#else
+  { "SetFilePointerEx",        (SYSCALL)0,                       0 },
+#endif
+
+#define osSetFilePointerEx ((BOOL(WINAPI*)(HANDLE,LARGE_INTEGER, \
+        PLARGE_INTEGER,DWORD))aSyscall[65].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "GetFileInformationByHandleEx", (SYSCALL)GetFileInformationByHandleEx, 0 },
+#else
+  { "GetFileInformationByHandleEx", (SYSCALL)0,                  0 },
+#endif
+
+#define osGetFileInformationByHandleEx ((BOOL(WINAPI*)(HANDLE, \
+        FILE_INFO_BY_HANDLE_CLASS,LPVOID,DWORD))aSyscall[66].pCurrent)
+
+#if SQLITE_OS_WINRT && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
+  { "MapViewOfFileFromApp",    (SYSCALL)MapViewOfFileFromApp,    0 },
+#else
+  { "MapViewOfFileFromApp",    (SYSCALL)0,                       0 },
+#endif
+
+#define osMapViewOfFileFromApp ((LPVOID(WINAPI*)(HANDLE,ULONG,ULONG64, \
+        SIZE_T))aSyscall[67].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "CreateFile2",             (SYSCALL)CreateFile2,             0 },
+#else
+  { "CreateFile2",             (SYSCALL)0,                       0 },
+#endif
+
+#define osCreateFile2 ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD,DWORD, \
+        LPCREATEFILE2_EXTENDED_PARAMETERS))aSyscall[68].pCurrent)
+
+#if SQLITE_OS_WINRT && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  { "LoadPackagedLibrary",     (SYSCALL)LoadPackagedLibrary,     0 },
+#else
+  { "LoadPackagedLibrary",     (SYSCALL)0,                       0 },
+#endif
+
+#define osLoadPackagedLibrary ((HMODULE(WINAPI*)(LPCWSTR, \
+        DWORD))aSyscall[69].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "GetTickCount64",          (SYSCALL)GetTickCount64,          0 },
+#else
+  { "GetTickCount64",          (SYSCALL)0,                       0 },
+#endif
+
+#define osGetTickCount64 ((ULONGLONG(WINAPI*)(VOID))aSyscall[70].pCurrent)
+
+#if SQLITE_OS_WINRT
+  { "GetNativeSystemInfo",     (SYSCALL)GetNativeSystemInfo,     0 },
+#else
+  { "GetNativeSystemInfo",     (SYSCALL)0,                       0 },
+#endif
+
+#define osGetNativeSystemInfo ((VOID(WINAPI*)( \
+        LPSYSTEM_INFO))aSyscall[71].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  { "OutputDebugStringA",      (SYSCALL)OutputDebugStringA,      0 },
+#else
+  { "OutputDebugStringA",      (SYSCALL)0,                       0 },
+#endif
+
+#define osOutputDebugStringA ((VOID(WINAPI*)(LPCSTR))aSyscall[72].pCurrent)
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  { "OutputDebugStringW",      (SYSCALL)OutputDebugStringW,      0 },
+#else
+  { "OutputDebugStringW",      (SYSCALL)0,                       0 },
+#endif
+
+#define osOutputDebugStringW ((VOID(WINAPI*)(LPCWSTR))aSyscall[73].pCurrent)
+
+  { "GetProcessHeap",          (SYSCALL)GetProcessHeap,          0 },
+
+#define osGetProcessHeap ((HANDLE(WINAPI*)(VOID))aSyscall[74].pCurrent)
+
+#if SQLITE_OS_WINRT && (!defined(SQLITE_OMIT_WAL) || SQLITE_MAX_MMAP_SIZE>0)
+  { "CreateFileMappingFromApp", (SYSCALL)CreateFileMappingFromApp, 0 },
+#else
+  { "CreateFileMappingFromApp", (SYSCALL)0,                      0 },
+#endif
+
+#define osCreateFileMappingFromApp ((HANDLE(WINAPI*)(HANDLE, \
+        LPSECURITY_ATTRIBUTES,ULONG,ULONG64,LPCWSTR))aSyscall[75].pCurrent)
+
+/*
+** NOTE: On some sub-platforms, the InterlockedCompareExchange "function"
+**       is really just a macro that uses a compiler intrinsic (e.g. x64).
+**       So do not try to make this is into a redefinable interface.
+*/
+#if defined(InterlockedCompareExchange)
+  { "InterlockedCompareExchange", (SYSCALL)0,                    0 },
+
+#define osInterlockedCompareExchange InterlockedCompareExchange
+#else
+  { "InterlockedCompareExchange", (SYSCALL)InterlockedCompareExchange, 0 },
+
+#define osInterlockedCompareExchange ((LONG(WINAPI*)(LONG \
+        SQLITE_WIN32_VOLATILE*, LONG,LONG))aSyscall[76].pCurrent)
+#endif /* defined(InterlockedCompareExchange) */
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_WIN32_USE_UUID
+  { "UuidCreate",               (SYSCALL)UuidCreate,             0 },
+#else
+  { "UuidCreate",               (SYSCALL)0,                      0 },
+#endif
+
+#define osUuidCreate ((RPC_STATUS(RPC_ENTRY*)(UUID*))aSyscall[77].pCurrent)
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_WIN32_USE_UUID
+  { "UuidCreateSequential",     (SYSCALL)UuidCreateSequential,   0 },
+#else
+  { "UuidCreateSequential",     (SYSCALL)0,                      0 },
+#endif
+
+#define osUuidCreateSequential \
+        ((RPC_STATUS(RPC_ENTRY*)(UUID*))aSyscall[78].pCurrent)
+
+#if !defined(SQLITE_NO_SYNC) && SQLITE_MAX_MMAP_SIZE>0
+  { "FlushViewOfFile",          (SYSCALL)FlushViewOfFile,        0 },
+#else
+  { "FlushViewOfFile",          (SYSCALL)0,                      0 },
+#endif
+
+#define osFlushViewOfFile \
+        ((BOOL(WINAPI*)(LPCVOID,SIZE_T))aSyscall[79].pCurrent)
+
+}; /* End of the overrideable system calls */
+
+/*
+** This is the xSetSystemCall() method of sqlite3_vfs for all of the
+** "win32" VFSes.  Return SQLITE_OK upon successfully updating the
+** system call pointer, or SQLITE_NOTFOUND if there is no configurable
+** system call named zName.
+*/
+static int winSetSystemCall(
+  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
+  const char *zName,            /* Name of system call to override */
+  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */
+){
+  unsigned int i;
+  int rc = SQLITE_NOTFOUND;
+
+  UNUSED_PARAMETER(pNotUsed);
+  if( zName==0 ){
+    /* If no zName is given, restore all system calls to their default
+    ** settings and return NULL
+    */
+    rc = SQLITE_OK;
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( aSyscall[i].pDefault ){
+        aSyscall[i].pCurrent = aSyscall[i].pDefault;
+      }
+    }
+  }else{
+    /* If zName is specified, operate on only the one system call
+    ** specified.
+    */
+    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ){
+        if( aSyscall[i].pDefault==0 ){
+          aSyscall[i].pDefault = aSyscall[i].pCurrent;
+        }
+        rc = SQLITE_OK;
+        if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault;
+        aSyscall[i].pCurrent = pNewFunc;
+        break;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the value of a system call.  Return NULL if zName is not a
+** recognized system call name.  NULL is also returned if the system call
+** is currently undefined.
+*/
+static sqlite3_syscall_ptr winGetSystemCall(
+  sqlite3_vfs *pNotUsed,
+  const char *zName
+){
+  unsigned int i;
+
+  UNUSED_PARAMETER(pNotUsed);
+  for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
+    if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent;
+  }
+  return 0;
+}
+
+/*
+** Return the name of the first system call after zName.  If zName==NULL
+** then return the name of the first system call.  Return NULL if zName
+** is the last system call or if zName is not the name of a valid
+** system call.
+*/
+static const char *winNextSystemCall(sqlite3_vfs *p, const char *zName){
+  int i = -1;
+
+  UNUSED_PARAMETER(p);
+  if( zName ){
+    for(i=0; i<ArraySize(aSyscall)-1; i++){
+      if( strcmp(zName, aSyscall[i].zName)==0 ) break;
+    }
+  }
+  for(i++; i<ArraySize(aSyscall); i++){
+    if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName;
+  }
+  return 0;
+}
+
+#ifdef SQLITE_WIN32_MALLOC
+/*
+** If a Win32 native heap has been configured, this function will attempt to
+** compact it.  Upon success, SQLITE_OK will be returned.  Upon failure, one
+** of SQLITE_NOMEM, SQLITE_ERROR, or SQLITE_NOTFOUND will be returned.  The
+** "pnLargest" argument, if non-zero, will be used to return the size of the
+** largest committed free block in the heap, in bytes.
+*/
+SQLITE_API int sqlite3_win32_compact_heap(LPUINT pnLargest){
+  int rc = SQLITE_OK;
+  UINT nLargest = 0;
+  HANDLE hHeap;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT
+  if( (nLargest=osHeapCompact(hHeap, SQLITE_WIN32_HEAP_FLAGS))==0 ){
+    DWORD lastErrno = osGetLastError();
+    if( lastErrno==NO_ERROR ){
+      sqlite3_log(SQLITE_NOMEM, "failed to HeapCompact (no space), heap=%p",
+                  (void*)hHeap);
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      sqlite3_log(SQLITE_ERROR, "failed to HeapCompact (%lu), heap=%p",
+                  osGetLastError(), (void*)hHeap);
+      rc = SQLITE_ERROR;
+    }
+  }
+#else
+  sqlite3_log(SQLITE_NOTFOUND, "failed to HeapCompact, heap=%p",
+              (void*)hHeap);
+  rc = SQLITE_NOTFOUND;
+#endif
+  if( pnLargest ) *pnLargest = nLargest;
+  return rc;
+}
+
+/*
+** If a Win32 native heap has been configured, this function will attempt to
+** destroy and recreate it.  If the Win32 native heap is not isolated and/or
+** the sqlite3_memory_used() function does not return zero, SQLITE_BUSY will
+** be returned and no changes will be made to the Win32 native heap.
+*/
+SQLITE_API int sqlite3_win32_reset_heap(){
+  int rc;
+  MUTEX_LOGIC( sqlite3_mutex *pMainMtx; ) /* The main static mutex */
+  MUTEX_LOGIC( sqlite3_mutex *pMem; )    /* The memsys static mutex */
+  MUTEX_LOGIC( pMainMtx = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  MUTEX_LOGIC( pMem = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM); )
+  sqlite3_mutex_enter(pMainMtx);
+  sqlite3_mutex_enter(pMem);
+  winMemAssertMagic();
+  if( winMemGetHeap()!=NULL && winMemGetOwned() && sqlite3_memory_used()==0 ){
+    /*
+    ** At this point, there should be no outstanding memory allocations on
+    ** the heap.  Also, since both the main and memsys locks are currently
+    ** being held by us, no other function (i.e. from another thread) should
+    ** be able to even access the heap.  Attempt to destroy and recreate our
+    ** isolated Win32 native heap now.
+    */
+    assert( winMemGetHeap()!=NULL );
+    assert( winMemGetOwned() );
+    assert( sqlite3_memory_used()==0 );
+    winMemShutdown(winMemGetDataPtr());
+    assert( winMemGetHeap()==NULL );
+    assert( !winMemGetOwned() );
+    assert( sqlite3_memory_used()==0 );
+    rc = winMemInit(winMemGetDataPtr());
+    assert( rc!=SQLITE_OK || winMemGetHeap()!=NULL );
+    assert( rc!=SQLITE_OK || winMemGetOwned() );
+    assert( rc!=SQLITE_OK || sqlite3_memory_used()==0 );
+  }else{
+    /*
+    ** The Win32 native heap cannot be modified because it may be in use.
+    */
+    rc = SQLITE_BUSY;
+  }
+  sqlite3_mutex_leave(pMem);
+  sqlite3_mutex_leave(pMainMtx);
+  return rc;
+}
+#endif /* SQLITE_WIN32_MALLOC */
+
+/*
+** This function outputs the specified (ANSI) string to the Win32 debugger
+** (if available).
+*/
+
+SQLITE_API void sqlite3_win32_write_debug(const char *zBuf, int nBuf){
+  char zDbgBuf[SQLITE_WIN32_DBG_BUF_SIZE];
+  int nMin = MIN(nBuf, (SQLITE_WIN32_DBG_BUF_SIZE - 1)); /* may be negative. */
+  if( nMin<-1 ) nMin = -1; /* all negative values become -1. */
+  assert( nMin==-1 || nMin==0 || nMin<SQLITE_WIN32_DBG_BUF_SIZE );
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zBuf ){
+    (void)SQLITE_MISUSE_BKPT;
+    return;
+  }
+#endif
+#if defined(SQLITE_WIN32_HAS_ANSI)
+  if( nMin>0 ){
+    memset(zDbgBuf, 0, SQLITE_WIN32_DBG_BUF_SIZE);
+    memcpy(zDbgBuf, zBuf, nMin);
+    osOutputDebugStringA(zDbgBuf);
+  }else{
+    osOutputDebugStringA(zBuf);
+  }
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+  memset(zDbgBuf, 0, SQLITE_WIN32_DBG_BUF_SIZE);
+  if ( osMultiByteToWideChar(
+          osAreFileApisANSI() ? CP_ACP : CP_OEMCP, 0, zBuf,
+          nMin, (LPWSTR)zDbgBuf, SQLITE_WIN32_DBG_BUF_SIZE/sizeof(WCHAR))<=0 ){
+    return;
+  }
+  osOutputDebugStringW((LPCWSTR)zDbgBuf);
+#else
+  if( nMin>0 ){
+    memset(zDbgBuf, 0, SQLITE_WIN32_DBG_BUF_SIZE);
+    memcpy(zDbgBuf, zBuf, nMin);
+    fprintf(stderr, "%s", zDbgBuf);
+  }else{
+    fprintf(stderr, "%s", zBuf);
+  }
+#endif
+}
+
+/*
+** The following routine suspends the current thread for at least ms
+** milliseconds.  This is equivalent to the Win32 Sleep() interface.
+*/
+#if SQLITE_OS_WINRT
+static HANDLE sleepObj = NULL;
+#endif
+
+SQLITE_API void sqlite3_win32_sleep(DWORD milliseconds){
+#if SQLITE_OS_WINRT
+  if ( sleepObj==NULL ){
+    sleepObj = osCreateEventExW(NULL, NULL, CREATE_EVENT_MANUAL_RESET,
+                                SYNCHRONIZE);
+  }
+  assert( sleepObj!=NULL );
+  osWaitForSingleObjectEx(sleepObj, milliseconds, FALSE);
+#else
+  osSleep(milliseconds);
+#endif
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0 && !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && \
+        SQLITE_THREADSAFE>0
+SQLITE_PRIVATE DWORD sqlite3Win32Wait(HANDLE hObject){
+  DWORD rc;
+  while( (rc = osWaitForSingleObjectEx(hObject, INFINITE,
+                                       TRUE))==WAIT_IO_COMPLETION ){}
+  return rc;
+}
+#endif
+
+/*
+** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
+** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
+**
+** Here is an interesting observation:  Win95, Win98, and WinME lack
+** the LockFileEx() API.  But we can still statically link against that
+** API as long as we don't call it when running Win95/98/ME.  A call to
+** this routine is used to determine if the host is Win95/98/ME or
+** WinNT/2K/XP so that we will know whether or not we can safely call
+** the LockFileEx() API.
+*/
+
+#if !SQLITE_WIN32_GETVERSIONEX
+# define osIsNT()  (1)
+#elif SQLITE_OS_WINCE || SQLITE_OS_WINRT || !defined(SQLITE_WIN32_HAS_ANSI)
+# define osIsNT()  (1)
+#elif !defined(SQLITE_WIN32_HAS_WIDE)
+# define osIsNT()  (0)
+#else
+# define osIsNT()  ((sqlite3_os_type==2) || sqlite3_win32_is_nt())
+#endif
+
+/*
+** This function determines if the machine is running a version of Windows
+** based on the NT kernel.
+*/
+SQLITE_API int sqlite3_win32_is_nt(void){
+#if SQLITE_OS_WINRT
+  /*
+  ** NOTE: The WinRT sub-platform is always assumed to be based on the NT
+  **       kernel.
+  */
+  return 1;
+#elif SQLITE_WIN32_GETVERSIONEX
+  if( osInterlockedCompareExchange(&sqlite3_os_type, 0, 0)==0 ){
+#if defined(SQLITE_WIN32_HAS_ANSI)
+    OSVERSIONINFOA sInfo;
+    sInfo.dwOSVersionInfoSize = sizeof(sInfo);
+    osGetVersionExA(&sInfo);
+    osInterlockedCompareExchange(&sqlite3_os_type,
+        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+    OSVERSIONINFOW sInfo;
+    sInfo.dwOSVersionInfoSize = sizeof(sInfo);
+    osGetVersionExW(&sInfo);
+    osInterlockedCompareExchange(&sqlite3_os_type,
+        (sInfo.dwPlatformId == VER_PLATFORM_WIN32_NT) ? 2 : 1, 0);
+#endif
+  }
+  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
+#elif SQLITE_TEST
+  return osInterlockedCompareExchange(&sqlite3_os_type, 2, 2)==2;
+#else
+  /*
+  ** NOTE: All sub-platforms where the GetVersionEx[AW] functions are
+  **       deprecated are always assumed to be based on the NT kernel.
+  */
+  return 1;
+#endif
+}
+
+#ifdef SQLITE_WIN32_MALLOC
+/*
+** Allocate nBytes of memory.
+*/
+static void *winMemMalloc(int nBytes){
+  HANDLE hHeap;
+  void *p;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+  assert( nBytes>=0 );
+  p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
+  if( !p ){
+    sqlite3_log(SQLITE_NOMEM, "failed to HeapAlloc %u bytes (%lu), heap=%p",
+                nBytes, osGetLastError(), (void*)hHeap);
+  }
+  return p;
+}
+
+/*
+** Free memory.
+*/
+static void winMemFree(void *pPrior){
+  HANDLE hHeap;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
+#endif
+  if( !pPrior ) return; /* Passing NULL to HeapFree is undefined. */
+  if( !osHeapFree(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) ){
+    sqlite3_log(SQLITE_NOMEM, "failed to HeapFree block %p (%lu), heap=%p",
+                pPrior, osGetLastError(), (void*)hHeap);
+  }
+}
+
+/*
+** Change the size of an existing memory allocation
+*/
+static void *winMemRealloc(void *pPrior, int nBytes){
+  HANDLE hHeap;
+  void *p;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
+#endif
+  assert( nBytes>=0 );
+  if( !pPrior ){
+    p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
+  }else{
+    p = osHeapReAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior, (SIZE_T)nBytes);
+  }
+  if( !p ){
+    sqlite3_log(SQLITE_NOMEM, "failed to %s %u bytes (%lu), heap=%p",
+                pPrior ? "HeapReAlloc" : "HeapAlloc", nBytes, osGetLastError(),
+                (void*)hHeap);
+  }
+  return p;
+}
+
+/*
+** Return the size of an outstanding allocation, in bytes.
+*/
+static int winMemSize(void *p){
+  HANDLE hHeap;
+  SIZE_T n;
+
+  winMemAssertMagic();
+  hHeap = winMemGetHeap();
+  assert( hHeap!=0 );
+  assert( hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, p) );
+#endif
+  if( !p ) return 0;
+  n = osHeapSize(hHeap, SQLITE_WIN32_HEAP_FLAGS, p);
+  if( n==(SIZE_T)-1 ){
+    sqlite3_log(SQLITE_NOMEM, "failed to HeapSize block %p (%lu), heap=%p",
+                p, osGetLastError(), (void*)hHeap);
+    return 0;
+  }
+  return (int)n;
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int winMemRoundup(int n){
+  return n;
+}
+
+/*
+** Initialize this module.
+*/
+static int winMemInit(void *pAppData){
+  winMemData *pWinMemData = (winMemData *)pAppData;
+
+  if( !pWinMemData ) return SQLITE_ERROR;
+  assert( pWinMemData->magic1==WINMEM_MAGIC1 );
+  assert( pWinMemData->magic2==WINMEM_MAGIC2 );
+
+#if !SQLITE_OS_WINRT && SQLITE_WIN32_HEAP_CREATE
+  if( !pWinMemData->hHeap ){
+    DWORD dwInitialSize = SQLITE_WIN32_HEAP_INIT_SIZE;
+    DWORD dwMaximumSize = (DWORD)sqlite3GlobalConfig.nHeap;
+    if( dwMaximumSize==0 ){
+      dwMaximumSize = SQLITE_WIN32_HEAP_MAX_SIZE;
+    }else if( dwInitialSize>dwMaximumSize ){
+      dwInitialSize = dwMaximumSize;
+    }
+    pWinMemData->hHeap = osHeapCreate(SQLITE_WIN32_HEAP_FLAGS,
+                                      dwInitialSize, dwMaximumSize);
+    if( !pWinMemData->hHeap ){
+      sqlite3_log(SQLITE_NOMEM,
+          "failed to HeapCreate (%lu), flags=%u, initSize=%lu, maxSize=%lu",
+          osGetLastError(), SQLITE_WIN32_HEAP_FLAGS, dwInitialSize,
+          dwMaximumSize);
+      return SQLITE_NOMEM_BKPT;
+    }
+    pWinMemData->bOwned = TRUE;
+    assert( pWinMemData->bOwned );
+  }
+#else
+  pWinMemData->hHeap = osGetProcessHeap();
+  if( !pWinMemData->hHeap ){
+    sqlite3_log(SQLITE_NOMEM,
+        "failed to GetProcessHeap (%lu)", osGetLastError());
+    return SQLITE_NOMEM_BKPT;
+  }
+  pWinMemData->bOwned = FALSE;
+  assert( !pWinMemData->bOwned );
+#endif
+  assert( pWinMemData->hHeap!=0 );
+  assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+  assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Deinitialize this module.
+*/
+static void winMemShutdown(void *pAppData){
+  winMemData *pWinMemData = (winMemData *)pAppData;
+
+  if( !pWinMemData ) return;
+  assert( pWinMemData->magic1==WINMEM_MAGIC1 );
+  assert( pWinMemData->magic2==WINMEM_MAGIC2 );
+
+  if( pWinMemData->hHeap ){
+    assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
+#if !SQLITE_OS_WINRT && defined(SQLITE_WIN32_MALLOC_VALIDATE)
+    assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
+#endif
+    if( pWinMemData->bOwned ){
+      if( !osHeapDestroy(pWinMemData->hHeap) ){
+        sqlite3_log(SQLITE_NOMEM, "failed to HeapDestroy (%lu), heap=%p",
+                    osGetLastError(), (void*)pWinMemData->hHeap);
+      }
+      pWinMemData->bOwned = FALSE;
+    }
+    pWinMemData->hHeap = NULL;
+  }
+}
+
+/*
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file. The
+** arguments specify the block of memory to manage.
+**
+** This routine is only called by sqlite3_config(), and therefore
+** is not required to be threadsafe (it is not).
+*/
+SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetWin32(void){
+  static const sqlite3_mem_methods winMemMethods = {
+    winMemMalloc,
+    winMemFree,
+    winMemRealloc,
+    winMemSize,
+    winMemRoundup,
+    winMemInit,
+    winMemShutdown,
+    &win_mem_data
+  };
+  return &winMemMethods;
+}
+
+SQLITE_PRIVATE void sqlite3MemSetDefault(void){
+  sqlite3_config(SQLITE_CONFIG_MALLOC, sqlite3MemGetWin32());
+}
+#endif /* SQLITE_WIN32_MALLOC */
+
+/*
+** Convert a UTF-8 string to Microsoft Unicode.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static LPWSTR winUtf8ToUnicode(const char *zText){
+  int nChar;
+  LPWSTR zWideText;
+
+  nChar = osMultiByteToWideChar(CP_UTF8, 0, zText, -1, NULL, 0);
+  if( nChar==0 ){
+    return 0;
+  }
+  zWideText = sqlite3MallocZero( nChar*sizeof(WCHAR) );
+  if( zWideText==0 ){
+    return 0;
+  }
+  nChar = osMultiByteToWideChar(CP_UTF8, 0, zText, -1, zWideText,
+                                nChar);
+  if( nChar==0 ){
+    sqlite3_free(zWideText);
+    zWideText = 0;
+  }
+  return zWideText;
+}
+
+/*
+** Convert a Microsoft Unicode string to UTF-8.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static char *winUnicodeToUtf8(LPCWSTR zWideText){
+  int nByte;
+  char *zText;
+
+  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideText, -1, 0, 0, 0, 0);
+  if( nByte == 0 ){
+    return 0;
+  }
+  zText = sqlite3MallocZero( nByte );
+  if( zText==0 ){
+    return 0;
+  }
+  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideText, -1, zText, nByte,
+                                0, 0);
+  if( nByte == 0 ){
+    sqlite3_free(zText);
+    zText = 0;
+  }
+  return zText;
+}
+
+/*
+** Convert an ANSI string to Microsoft Unicode, using the ANSI or OEM
+** code page.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static LPWSTR winMbcsToUnicode(const char *zText, int useAnsi){
+  int nByte;
+  LPWSTR zMbcsText;
+  int codepage = useAnsi ? CP_ACP : CP_OEMCP;
+
+  nByte = osMultiByteToWideChar(codepage, 0, zText, -1, NULL,
+                                0)*sizeof(WCHAR);
+  if( nByte==0 ){
+    return 0;
+  }
+  zMbcsText = sqlite3MallocZero( nByte*sizeof(WCHAR) );
+  if( zMbcsText==0 ){
+    return 0;
+  }
+  nByte = osMultiByteToWideChar(codepage, 0, zText, -1, zMbcsText,
+                                nByte);
+  if( nByte==0 ){
+    sqlite3_free(zMbcsText);
+    zMbcsText = 0;
+  }
+  return zMbcsText;
+}
+
+/*
+** Convert a Microsoft Unicode string to a multi-byte character string,
+** using the ANSI or OEM code page.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static char *winUnicodeToMbcs(LPCWSTR zWideText, int useAnsi){
+  int nByte;
+  char *zText;
+  int codepage = useAnsi ? CP_ACP : CP_OEMCP;
+
+  nByte = osWideCharToMultiByte(codepage, 0, zWideText, -1, 0, 0, 0, 0);
+  if( nByte == 0 ){
+    return 0;
+  }
+  zText = sqlite3MallocZero( nByte );
+  if( zText==0 ){
+    return 0;
+  }
+  nByte = osWideCharToMultiByte(codepage, 0, zWideText, -1, zText,
+                                nByte, 0, 0);
+  if( nByte == 0 ){
+    sqlite3_free(zText);
+    zText = 0;
+  }
+  return zText;
+}
+
+/*
+** Convert a multi-byte character string to UTF-8.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static char *winMbcsToUtf8(const char *zText, int useAnsi){
+  char *zTextUtf8;
+  LPWSTR zTmpWide;
+
+  zTmpWide = winMbcsToUnicode(zText, useAnsi);
+  if( zTmpWide==0 ){
+    return 0;
+  }
+  zTextUtf8 = winUnicodeToUtf8(zTmpWide);
+  sqlite3_free(zTmpWide);
+  return zTextUtf8;
+}
+
+/*
+** Convert a UTF-8 string to a multi-byte character string.
+**
+** Space to hold the returned string is obtained from sqlite3_malloc().
+*/
+static char *winUtf8ToMbcs(const char *zText, int useAnsi){
+  char *zTextMbcs;
+  LPWSTR zTmpWide;
+
+  zTmpWide = winUtf8ToUnicode(zText);
+  if( zTmpWide==0 ){
+    return 0;
+  }
+  zTextMbcs = winUnicodeToMbcs(zTmpWide, useAnsi);
+  sqlite3_free(zTmpWide);
+  return zTextMbcs;
+}
+
+/*
+** This is a public wrapper for the winUtf8ToUnicode() function.
+*/
+SQLITE_API LPWSTR sqlite3_win32_utf8_to_unicode(const char *zText){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winUtf8ToUnicode(zText);
+}
+
+/*
+** This is a public wrapper for the winUnicodeToUtf8() function.
+*/
+SQLITE_API char *sqlite3_win32_unicode_to_utf8(LPCWSTR zWideText){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zWideText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winUnicodeToUtf8(zWideText);
+}
+
+/*
+** This is a public wrapper for the winMbcsToUtf8() function.
+*/
+SQLITE_API char *sqlite3_win32_mbcs_to_utf8(const char *zText){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winMbcsToUtf8(zText, osAreFileApisANSI());
+}
+
+/*
+** This is a public wrapper for the winMbcsToUtf8() function.
+*/
+SQLITE_API char *sqlite3_win32_mbcs_to_utf8_v2(const char *zText, int useAnsi){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winMbcsToUtf8(zText, useAnsi);
+}
+
+/*
+** This is a public wrapper for the winUtf8ToMbcs() function.
+*/
+SQLITE_API char *sqlite3_win32_utf8_to_mbcs(const char *zText){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winUtf8ToMbcs(zText, osAreFileApisANSI());
+}
+
+/*
+** This is a public wrapper for the winUtf8ToMbcs() function.
+*/
+SQLITE_API char *sqlite3_win32_utf8_to_mbcs_v2(const char *zText, int useAnsi){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !zText ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize() ) return 0;
+#endif
+  return winUtf8ToMbcs(zText, useAnsi);
+}
+
+/*
+** This function is the same as sqlite3_win32_set_directory (below); however,
+** it accepts a UTF-8 string.
+*/
+SQLITE_API int sqlite3_win32_set_directory8(
+  unsigned long type, /* Identifier for directory being set or reset */
+  const char *zValue  /* New value for directory being set or reset */
+){
+  char **ppDirectory = 0;
+  int rc;
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  if( type==SQLITE_WIN32_DATA_DIRECTORY_TYPE ){
+    ppDirectory = &sqlite3_data_directory;
+  }else if( type==SQLITE_WIN32_TEMP_DIRECTORY_TYPE ){
+    ppDirectory = &sqlite3_temp_directory;
+  }
+  assert( !ppDirectory || type==SQLITE_WIN32_DATA_DIRECTORY_TYPE
+          || type==SQLITE_WIN32_TEMP_DIRECTORY_TYPE
+  );
+  assert( !ppDirectory || sqlite3MemdebugHasType(*ppDirectory, MEMTYPE_HEAP) );
+  if( ppDirectory ){
+    char *zCopy = 0;
+    if( zValue && zValue[0] ){
+      zCopy = sqlite3_mprintf("%s", zValue);
+      if ( zCopy==0 ){
+        rc = SQLITE_NOMEM_BKPT;
+        goto set_directory8_done;
+      }
+    }
+    sqlite3_free(*ppDirectory);
+    *ppDirectory = zCopy;
+    rc = SQLITE_OK;
+  }else{
+    rc = SQLITE_ERROR;
+  }
+set_directory8_done:
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return rc;
+}
+
+/*
+** This function is the same as sqlite3_win32_set_directory (below); however,
+** it accepts a UTF-16 string.
+*/
+SQLITE_API int sqlite3_win32_set_directory16(
+  unsigned long type, /* Identifier for directory being set or reset */
+  const void *zValue  /* New value for directory being set or reset */
+){
+  int rc;
+  char *zUtf8 = 0;
+  if( zValue ){
+    zUtf8 = sqlite3_win32_unicode_to_utf8(zValue);
+    if( zUtf8==0 ) return SQLITE_NOMEM_BKPT;
+  }
+  rc = sqlite3_win32_set_directory8(type, zUtf8);
+  if( zUtf8 ) sqlite3_free(zUtf8);
+  return rc;
+}
+
+/*
+** This function sets the data directory or the temporary directory based on
+** the provided arguments.  The type argument must be 1 in order to set the
+** data directory or 2 in order to set the temporary directory.  The zValue
+** argument is the name of the directory to use.  The return value will be
+** SQLITE_OK if successful.
+*/
+SQLITE_API int sqlite3_win32_set_directory(
+  unsigned long type, /* Identifier for directory being set or reset */
+  void *zValue        /* New value for directory being set or reset */
+){
+  return sqlite3_win32_set_directory16(type, zValue);
+}
+
+/*
+** The return value of winGetLastErrorMsg
+** is zero if the error message fits in the buffer, or non-zero
+** otherwise (if the message was truncated).
+*/
+static int winGetLastErrorMsg(DWORD lastErrno, int nBuf, char *zBuf){
+  /* FormatMessage returns 0 on failure.  Otherwise it
+  ** returns the number of TCHARs written to the output
+  ** buffer, excluding the terminating null char.
+  */
+  DWORD dwLen = 0;
+  char *zOut = 0;
+
+  if( osIsNT() ){
+#if SQLITE_OS_WINRT
+    WCHAR zTempWide[SQLITE_WIN32_MAX_ERRMSG_CHARS+1];
+    dwLen = osFormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL,
+                             lastErrno,
+                             0,
+                             zTempWide,
+                             SQLITE_WIN32_MAX_ERRMSG_CHARS,
+                             0);
+#else
+    LPWSTR zTempWide = NULL;
+    dwLen = osFormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                             FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL,
+                             lastErrno,
+                             0,
+                             (LPWSTR) &zTempWide,
+                             0,
+                             0);
+#endif
+    if( dwLen > 0 ){
+      /* allocate a buffer and convert to UTF8 */
+      sqlite3BeginBenignMalloc();
+      zOut = winUnicodeToUtf8(zTempWide);
+      sqlite3EndBenignMalloc();
+#if !SQLITE_OS_WINRT
+      /* free the system buffer allocated by FormatMessage */
+      osLocalFree(zTempWide);
+#endif
+    }
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    char *zTemp = NULL;
+    dwLen = osFormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                             FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL,
+                             lastErrno,
+                             0,
+                             (LPSTR) &zTemp,
+                             0,
+                             0);
+    if( dwLen > 0 ){
+      /* allocate a buffer and convert to UTF8 */
+      sqlite3BeginBenignMalloc();
+      zOut = winMbcsToUtf8(zTemp, osAreFileApisANSI());
+      sqlite3EndBenignMalloc();
+      /* free the system buffer allocated by FormatMessage */
+      osLocalFree(zTemp);
+    }
+  }
+#endif
+  if( 0 == dwLen ){
+    sqlite3_snprintf(nBuf, zBuf, "OsError 0x%lx (%lu)", lastErrno, lastErrno);
+  }else{
+    /* copy a maximum of nBuf chars to output buffer */
+    sqlite3_snprintf(nBuf, zBuf, "%s", zOut);
+    /* free the UTF8 buffer */
+    sqlite3_free(zOut);
+  }
+  return 0;
+}
+
+/*
+**
+** This function - winLogErrorAtLine() - is only ever called via the macro
+** winLogError().
+**
+** This routine is invoked after an error occurs in an OS function.
+** It logs a message using sqlite3_log() containing the current value of
+** error code and, if possible, the human-readable equivalent from
+** FormatMessage.
+**
+** The first argument passed to the macro should be the error code that
+** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN).
+** The two subsequent arguments should be the name of the OS function that
+** failed and the associated file-system path, if any.
+*/
+#define winLogError(a,b,c,d)   winLogErrorAtLine(a,b,c,d,__LINE__)
+static int winLogErrorAtLine(
+  int errcode,                    /* SQLite error code */
+  DWORD lastErrno,                /* Win32 last error */
+  const char *zFunc,              /* Name of OS function that failed */
+  const char *zPath,              /* File path associated with error */
+  int iLine                       /* Source line number where error occurred */
+){
+  char zMsg[500];                 /* Human readable error text */
+  int i;                          /* Loop counter */
+
+  zMsg[0] = 0;
+  winGetLastErrorMsg(lastErrno, sizeof(zMsg), zMsg);
+  assert( errcode!=SQLITE_OK );
+  if( zPath==0 ) zPath = "";
+  for(i=0; zMsg[i] && zMsg[i]!='\r' && zMsg[i]!='\n'; i++){}
+  zMsg[i] = 0;
+  sqlite3_log(errcode,
+      "os_win.c:%d: (%lu) %s(%s) - %s",
+      iLine, lastErrno, zFunc, zPath, zMsg
+  );
+
+  return errcode;
+}
+
+/*
+** The number of times that a ReadFile(), WriteFile(), and DeleteFile()
+** will be retried following a locking error - probably caused by
+** antivirus software.  Also the initial delay before the first retry.
+** The delay increases linearly with each retry.
+*/
+#ifndef SQLITE_WIN32_IOERR_RETRY
+# define SQLITE_WIN32_IOERR_RETRY 10
+#endif
+#ifndef SQLITE_WIN32_IOERR_RETRY_DELAY
+# define SQLITE_WIN32_IOERR_RETRY_DELAY 25
+#endif
+static int winIoerrRetry = SQLITE_WIN32_IOERR_RETRY;
+static int winIoerrRetryDelay = SQLITE_WIN32_IOERR_RETRY_DELAY;
+
+/*
+** The "winIoerrCanRetry1" macro is used to determine if a particular I/O
+** error code obtained via GetLastError() is eligible to be retried.  It
+** must accept the error code DWORD as its only argument and should return
+** non-zero if the error code is transient in nature and the operation
+** responsible for generating the original error might succeed upon being
+** retried.  The argument to this macro should be a variable.
+**
+** Additionally, a macro named "winIoerrCanRetry2" may be defined.  If it
+** is defined, it will be consulted only when the macro "winIoerrCanRetry1"
+** returns zero.  The "winIoerrCanRetry2" macro is completely optional and
+** may be used to include additional error codes in the set that should
+** result in the failing I/O operation being retried by the caller.  If
+** defined, the "winIoerrCanRetry2" macro must exhibit external semantics
+** identical to those of the "winIoerrCanRetry1" macro.
+*/
+#if !defined(winIoerrCanRetry1)
+#define winIoerrCanRetry1(a) (((a)==ERROR_ACCESS_DENIED)        || \
+                              ((a)==ERROR_SHARING_VIOLATION)    || \
+                              ((a)==ERROR_LOCK_VIOLATION)       || \
+                              ((a)==ERROR_DEV_NOT_EXIST)        || \
+                              ((a)==ERROR_NETNAME_DELETED)      || \
+                              ((a)==ERROR_SEM_TIMEOUT)          || \
+                              ((a)==ERROR_NETWORK_UNREACHABLE))
+#endif
+
+/*
+** If a ReadFile() or WriteFile() error occurs, invoke this routine
+** to see if it should be retried.  Return TRUE to retry.  Return FALSE
+** to give up with an error.
+*/
+static int winRetryIoerr(int *pnRetry, DWORD *pError){
+  DWORD e = osGetLastError();
+  if( *pnRetry>=winIoerrRetry ){
+    if( pError ){
+      *pError = e;
+    }
+    return 0;
+  }
+  if( winIoerrCanRetry1(e) ){
+    sqlite3_win32_sleep(winIoerrRetryDelay*(1+*pnRetry));
+    ++*pnRetry;
+    return 1;
+  }
+#if defined(winIoerrCanRetry2)
+  else if( winIoerrCanRetry2(e) ){
+    sqlite3_win32_sleep(winIoerrRetryDelay*(1+*pnRetry));
+    ++*pnRetry;
+    return 1;
+  }
+#endif
+  if( pError ){
+    *pError = e;
+  }
+  return 0;
+}
+
+/*
+** Log a I/O error retry episode.
+*/
+static void winLogIoerr(int nRetry, int lineno){
+  if( nRetry ){
+    sqlite3_log(SQLITE_NOTICE,
+      "delayed %dms for lock/sharing conflict at line %d",
+      winIoerrRetryDelay*nRetry*(nRetry+1)/2, lineno
+    );
+  }
+}
+
+/*
+** This #if does not rely on the SQLITE_OS_WINCE define because the
+** corresponding section in "date.c" cannot use it.
+*/
+#if !defined(SQLITE_OMIT_LOCALTIME) && defined(_WIN32_WCE) && \
+    (!defined(SQLITE_MSVC_LOCALTIME_API) || !SQLITE_MSVC_LOCALTIME_API)
+/*
+** The MSVC CRT on Windows CE may not have a localtime() function.
+** So define a substitute.
+*/
+/* #  include <time.h> */
+struct tm *__cdecl localtime(const time_t *t)
+{
+  static struct tm y;
+  FILETIME uTm, lTm;
+  SYSTEMTIME pTm;
+  sqlite3_int64 t64;
+  t64 = *t;
+  t64 = (t64 + 11644473600)*10000000;
+  uTm.dwLowDateTime = (DWORD)(t64 & 0xFFFFFFFF);
+  uTm.dwHighDateTime= (DWORD)(t64 >> 32);
+  osFileTimeToLocalFileTime(&uTm,&lTm);
+  osFileTimeToSystemTime(&lTm,&pTm);
+  y.tm_year = pTm.wYear - 1900;
+  y.tm_mon = pTm.wMonth - 1;
+  y.tm_wday = pTm.wDayOfWeek;
+  y.tm_mday = pTm.wDay;
+  y.tm_hour = pTm.wHour;
+  y.tm_min = pTm.wMinute;
+  y.tm_sec = pTm.wSecond;
+  return &y;
+}
+#endif
+
+#if SQLITE_OS_WINCE
+/*************************************************************************
+** This section contains code for WinCE only.
+*/
+#define HANDLE_TO_WINFILE(a) (winFile*)&((char*)a)[-(int)offsetof(winFile,h)]
+
+/*
+** Acquire a lock on the handle h
+*/
+static void winceMutexAcquire(HANDLE h){
+   DWORD dwErr;
+   do {
+     dwErr = osWaitForSingleObject(h, INFINITE);
+   } while (dwErr != WAIT_OBJECT_0 && dwErr != WAIT_ABANDONED);
+}
+/*
+** Release a lock acquired by winceMutexAcquire()
+*/
+#define winceMutexRelease(h) ReleaseMutex(h)
+
+/*
+** Create the mutex and shared memory used for locking in the file
+** descriptor pFile
+*/
+static int winceCreateLock(const char *zFilename, winFile *pFile){
+  LPWSTR zTok;
+  LPWSTR zName;
+  DWORD lastErrno;
+  BOOL bLogged = FALSE;
+  BOOL bInit = TRUE;
+
+  zName = winUtf8ToUnicode(zFilename);
+  if( zName==0 ){
+    /* out of memory */
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+
+  /* Initialize the local lockdata */
+  memset(&pFile->local, 0, sizeof(pFile->local));
+
+  /* Replace the backslashes from the filename and lowercase it
+  ** to derive a mutex name. */
+  zTok = osCharLowerW(zName);
+  for (;*zTok;zTok++){
+    if (*zTok == '\\') *zTok = '_';
+  }
+
+  /* Create/open the named mutex */
+  pFile->hMutex = osCreateMutexW(NULL, FALSE, zName);
+  if (!pFile->hMutex){
+    pFile->lastErrno = osGetLastError();
+    sqlite3_free(zName);
+    return winLogError(SQLITE_IOERR, pFile->lastErrno,
+                       "winceCreateLock1", zFilename);
+  }
+
+  /* Acquire the mutex before continuing */
+  winceMutexAcquire(pFile->hMutex);
+
+  /* Since the names of named mutexes, semaphores, file mappings etc are
+  ** case-sensitive, take advantage of that by uppercasing the mutex name
+  ** and using that as the shared filemapping name.
+  */
+  osCharUpperW(zName);
+  pFile->hShared = osCreateFileMappingW(INVALID_HANDLE_VALUE, NULL,
+                                        PAGE_READWRITE, 0, sizeof(winceLock),
+                                        zName);
+
+  /* Set a flag that indicates we're the first to create the memory so it
+  ** must be zero-initialized */
+  lastErrno = osGetLastError();
+  if (lastErrno == ERROR_ALREADY_EXISTS){
+    bInit = FALSE;
+  }
+
+  sqlite3_free(zName);
+
+  /* If we succeeded in making the shared memory handle, map it. */
+  if( pFile->hShared ){
+    pFile->shared = (winceLock*)osMapViewOfFile(pFile->hShared,
+             FILE_MAP_READ|FILE_MAP_WRITE, 0, 0, sizeof(winceLock));
+    /* If mapping failed, close the shared memory handle and erase it */
+    if( !pFile->shared ){
+      pFile->lastErrno = osGetLastError();
+      winLogError(SQLITE_IOERR, pFile->lastErrno,
+                  "winceCreateLock2", zFilename);
+      bLogged = TRUE;
+      osCloseHandle(pFile->hShared);
+      pFile->hShared = NULL;
+    }
+  }
+
+  /* If shared memory could not be created, then close the mutex and fail */
+  if( pFile->hShared==NULL ){
+    if( !bLogged ){
+      pFile->lastErrno = lastErrno;
+      winLogError(SQLITE_IOERR, pFile->lastErrno,
+                  "winceCreateLock3", zFilename);
+      bLogged = TRUE;
+    }
+    winceMutexRelease(pFile->hMutex);
+    osCloseHandle(pFile->hMutex);
+    pFile->hMutex = NULL;
+    return SQLITE_IOERR;
+  }
+
+  /* Initialize the shared memory if we're supposed to */
+  if( bInit ){
+    memset(pFile->shared, 0, sizeof(winceLock));
+  }
+
+  winceMutexRelease(pFile->hMutex);
+  return SQLITE_OK;
+}
+
+/*
+** Destroy the part of winFile that deals with wince locks
+*/
+static void winceDestroyLock(winFile *pFile){
+  if (pFile->hMutex){
+    /* Acquire the mutex */
+    winceMutexAcquire(pFile->hMutex);
+
+    /* The following blocks should probably assert in debug mode, but they
+       are to cleanup in case any locks remained open */
+    if (pFile->local.nReaders){
+      pFile->shared->nReaders --;
+    }
+    if (pFile->local.bReserved){
+      pFile->shared->bReserved = FALSE;
+    }
+    if (pFile->local.bPending){
+      pFile->shared->bPending = FALSE;
+    }
+    if (pFile->local.bExclusive){
+      pFile->shared->bExclusive = FALSE;
+    }
+
+    /* De-reference and close our copy of the shared memory handle */
+    osUnmapViewOfFile(pFile->shared);
+    osCloseHandle(pFile->hShared);
+
+    /* Done with the mutex */
+    winceMutexRelease(pFile->hMutex);
+    osCloseHandle(pFile->hMutex);
+    pFile->hMutex = NULL;
+  }
+}
+
+/*
+** An implementation of the LockFile() API of Windows for CE
+*/
+static BOOL winceLockFile(
+  LPHANDLE phFile,
+  DWORD dwFileOffsetLow,
+  DWORD dwFileOffsetHigh,
+  DWORD nNumberOfBytesToLockLow,
+  DWORD nNumberOfBytesToLockHigh
+){
+  winFile *pFile = HANDLE_TO_WINFILE(phFile);
+  BOOL bReturn = FALSE;
+
+  UNUSED_PARAMETER(dwFileOffsetHigh);
+  UNUSED_PARAMETER(nNumberOfBytesToLockHigh);
+
+  if (!pFile->hMutex) return TRUE;
+  winceMutexAcquire(pFile->hMutex);
+
+  /* Wanting an exclusive lock? */
+  if (dwFileOffsetLow == (DWORD)SHARED_FIRST
+       && nNumberOfBytesToLockLow == (DWORD)SHARED_SIZE){
+    if (pFile->shared->nReaders == 0 && pFile->shared->bExclusive == 0){
+       pFile->shared->bExclusive = TRUE;
+       pFile->local.bExclusive = TRUE;
+       bReturn = TRUE;
+    }
+  }
+
+  /* Want a read-only lock? */
+  else if (dwFileOffsetLow == (DWORD)SHARED_FIRST &&
+           nNumberOfBytesToLockLow == 1){
+    if (pFile->shared->bExclusive == 0){
+      pFile->local.nReaders ++;
+      if (pFile->local.nReaders == 1){
+        pFile->shared->nReaders ++;
+      }
+      bReturn = TRUE;
+    }
+  }
+
+  /* Want a pending lock? */
+  else if (dwFileOffsetLow == (DWORD)PENDING_BYTE
+           && nNumberOfBytesToLockLow == 1){
+    /* If no pending lock has been acquired, then acquire it */
+    if (pFile->shared->bPending == 0) {
+      pFile->shared->bPending = TRUE;
+      pFile->local.bPending = TRUE;
+      bReturn = TRUE;
+    }
+  }
+
+  /* Want a reserved lock? */
+  else if (dwFileOffsetLow == (DWORD)RESERVED_BYTE
+           && nNumberOfBytesToLockLow == 1){
+    if (pFile->shared->bReserved == 0) {
+      pFile->shared->bReserved = TRUE;
+      pFile->local.bReserved = TRUE;
+      bReturn = TRUE;
+    }
+  }
+
+  winceMutexRelease(pFile->hMutex);
+  return bReturn;
+}
+
+/*
+** An implementation of the UnlockFile API of Windows for CE
+*/
+static BOOL winceUnlockFile(
+  LPHANDLE phFile,
+  DWORD dwFileOffsetLow,
+  DWORD dwFileOffsetHigh,
+  DWORD nNumberOfBytesToUnlockLow,
+  DWORD nNumberOfBytesToUnlockHigh
+){
+  winFile *pFile = HANDLE_TO_WINFILE(phFile);
+  BOOL bReturn = FALSE;
+
+  UNUSED_PARAMETER(dwFileOffsetHigh);
+  UNUSED_PARAMETER(nNumberOfBytesToUnlockHigh);
+
+  if (!pFile->hMutex) return TRUE;
+  winceMutexAcquire(pFile->hMutex);
+
+  /* Releasing a reader lock or an exclusive lock */
+  if (dwFileOffsetLow == (DWORD)SHARED_FIRST){
+    /* Did we have an exclusive lock? */
+    if (pFile->local.bExclusive){
+      assert(nNumberOfBytesToUnlockLow == (DWORD)SHARED_SIZE);
+      pFile->local.bExclusive = FALSE;
+      pFile->shared->bExclusive = FALSE;
+      bReturn = TRUE;
+    }
+
+    /* Did we just have a reader lock? */
+    else if (pFile->local.nReaders){
+      assert(nNumberOfBytesToUnlockLow == (DWORD)SHARED_SIZE
+             || nNumberOfBytesToUnlockLow == 1);
+      pFile->local.nReaders --;
+      if (pFile->local.nReaders == 0)
+      {
+        pFile->shared->nReaders --;
+      }
+      bReturn = TRUE;
+    }
+  }
+
+  /* Releasing a pending lock */
+  else if (dwFileOffsetLow == (DWORD)PENDING_BYTE
+           && nNumberOfBytesToUnlockLow == 1){
+    if (pFile->local.bPending){
+      pFile->local.bPending = FALSE;
+      pFile->shared->bPending = FALSE;
+      bReturn = TRUE;
+    }
+  }
+  /* Releasing a reserved lock */
+  else if (dwFileOffsetLow == (DWORD)RESERVED_BYTE
+           && nNumberOfBytesToUnlockLow == 1){
+    if (pFile->local.bReserved) {
+      pFile->local.bReserved = FALSE;
+      pFile->shared->bReserved = FALSE;
+      bReturn = TRUE;
+    }
+  }
+
+  winceMutexRelease(pFile->hMutex);
+  return bReturn;
+}
+/*
+** End of the special code for wince
+*****************************************************************************/
+#endif /* SQLITE_OS_WINCE */
+
+/*
+** Lock a file region.
+*/
+static BOOL winLockFile(
+  LPHANDLE phFile,
+  DWORD flags,
+  DWORD offsetLow,
+  DWORD offsetHigh,
+  DWORD numBytesLow,
+  DWORD numBytesHigh
+){
+#if SQLITE_OS_WINCE
+  /*
+  ** NOTE: Windows CE is handled differently here due its lack of the Win32
+  **       API LockFile.
+  */
+  return winceLockFile(phFile, offsetLow, offsetHigh,
+                       numBytesLow, numBytesHigh);
+#else
+  if( osIsNT() ){
+    OVERLAPPED ovlp;
+    memset(&ovlp, 0, sizeof(OVERLAPPED));
+    ovlp.Offset = offsetLow;
+    ovlp.OffsetHigh = offsetHigh;
+    return osLockFileEx(*phFile, flags, 0, numBytesLow, numBytesHigh, &ovlp);
+  }else{
+    return osLockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
+                      numBytesHigh);
+  }
+#endif
+}
+
+/*
+** Unlock a file region.
+ */
+static BOOL winUnlockFile(
+  LPHANDLE phFile,
+  DWORD offsetLow,
+  DWORD offsetHigh,
+  DWORD numBytesLow,
+  DWORD numBytesHigh
+){
+#if SQLITE_OS_WINCE
+  /*
+  ** NOTE: Windows CE is handled differently here due its lack of the Win32
+  **       API UnlockFile.
+  */
+  return winceUnlockFile(phFile, offsetLow, offsetHigh,
+                         numBytesLow, numBytesHigh);
+#else
+  if( osIsNT() ){
+    OVERLAPPED ovlp;
+    memset(&ovlp, 0, sizeof(OVERLAPPED));
+    ovlp.Offset = offsetLow;
+    ovlp.OffsetHigh = offsetHigh;
+    return osUnlockFileEx(*phFile, 0, numBytesLow, numBytesHigh, &ovlp);
+  }else{
+    return osUnlockFile(*phFile, offsetLow, offsetHigh, numBytesLow,
+                        numBytesHigh);
+  }
+#endif
+}
+
+/*****************************************************************************
+** The next group of routines implement the I/O methods specified
+** by the sqlite3_io_methods object.
+******************************************************************************/
+
+/*
+** Some Microsoft compilers lack this definition.
+*/
+#ifndef INVALID_SET_FILE_POINTER
+# define INVALID_SET_FILE_POINTER ((DWORD)-1)
+#endif
+
+/*
+** Move the current position of the file handle passed as the first
+** argument to offset iOffset within the file. If successful, return 0.
+** Otherwise, set pFile->lastErrno and return non-zero.
+*/
+static int winSeekFile(winFile *pFile, sqlite3_int64 iOffset){
+#if !SQLITE_OS_WINRT
+  LONG upperBits;                 /* Most sig. 32 bits of new offset */
+  LONG lowerBits;                 /* Least sig. 32 bits of new offset */
+  DWORD dwRet;                    /* Value returned by SetFilePointer() */
+  DWORD lastErrno;                /* Value returned by GetLastError() */
+
+  OSTRACE(("SEEK file=%p, offset=%lld\n", pFile->h, iOffset));
+
+  upperBits = (LONG)((iOffset>>32) & 0x7fffffff);
+  lowerBits = (LONG)(iOffset & 0xffffffff);
+
+  /* API oddity: If successful, SetFilePointer() returns a dword
+  ** containing the lower 32-bits of the new file-offset. Or, if it fails,
+  ** it returns INVALID_SET_FILE_POINTER. However according to MSDN,
+  ** INVALID_SET_FILE_POINTER may also be a valid new offset. So to determine
+  ** whether an error has actually occurred, it is also necessary to call
+  ** GetLastError().
+  */
+  dwRet = osSetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
+
+  if( (dwRet==INVALID_SET_FILE_POINTER
+      && ((lastErrno = osGetLastError())!=NO_ERROR)) ){
+    pFile->lastErrno = lastErrno;
+    winLogError(SQLITE_IOERR_SEEK, pFile->lastErrno,
+                "winSeekFile", pFile->zPath);
+    OSTRACE(("SEEK file=%p, rc=SQLITE_IOERR_SEEK\n", pFile->h));
+    return 1;
+  }
+
+  OSTRACE(("SEEK file=%p, rc=SQLITE_OK\n", pFile->h));
+  return 0;
+#else
+  /*
+  ** Same as above, except that this implementation works for WinRT.
+  */
+
+  LARGE_INTEGER x;                /* The new offset */
+  BOOL bRet;                      /* Value returned by SetFilePointerEx() */
+
+  x.QuadPart = iOffset;
+  bRet = osSetFilePointerEx(pFile->h, x, 0, FILE_BEGIN);
+
+  if(!bRet){
+    pFile->lastErrno = osGetLastError();
+    winLogError(SQLITE_IOERR_SEEK, pFile->lastErrno,
+                "winSeekFile", pFile->zPath);
+    OSTRACE(("SEEK file=%p, rc=SQLITE_IOERR_SEEK\n", pFile->h));
+    return 1;
+  }
+
+  OSTRACE(("SEEK file=%p, rc=SQLITE_OK\n", pFile->h));
+  return 0;
+#endif
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/* Forward references to VFS helper methods used for memory mapped files */
+static int winMapfile(winFile*, sqlite3_int64);
+static int winUnmapfile(winFile*);
+#endif
+
+/*
+** Close a file.
+**
+** It is reported that an attempt to close a handle might sometimes
+** fail.  This is a very unreasonable result, but Windows is notorious
+** for being unreasonable so I do not doubt that it might happen.  If
+** the close fails, we pause for 100 milliseconds and try again.  As
+** many as MX_CLOSE_ATTEMPT attempts to close the handle are made before
+** giving up and returning an error.
+*/
+#define MX_CLOSE_ATTEMPT 3
+static int winClose(sqlite3_file *id){
+  int rc, cnt = 0;
+  winFile *pFile = (winFile*)id;
+
+  assert( id!=0 );
+#ifndef SQLITE_OMIT_WAL
+  assert( pFile->pShm==0 );
+#endif
+  assert( pFile->h!=NULL && pFile->h!=INVALID_HANDLE_VALUE );
+  OSTRACE(("CLOSE pid=%lu, pFile=%p, file=%p\n",
+           osGetCurrentProcessId(), pFile, pFile->h));
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  winUnmapfile(pFile);
+#endif
+
+  do{
+    rc = osCloseHandle(pFile->h);
+    /* SimulateIOError( rc=0; cnt=MX_CLOSE_ATTEMPT; ); */
+  }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (sqlite3_win32_sleep(100), 1) );
+#if SQLITE_OS_WINCE
+#define WINCE_DELETION_ATTEMPTS 3
+  {
+    winVfsAppData *pAppData = (winVfsAppData*)pFile->pVfs->pAppData;
+    if( pAppData==NULL || !pAppData->bNoLock ){
+      winceDestroyLock(pFile);
+    }
+  }
+  if( pFile->zDeleteOnClose ){
+    int cnt = 0;
+    while(
+           osDeleteFileW(pFile->zDeleteOnClose)==0
+        && osGetFileAttributesW(pFile->zDeleteOnClose)!=0xffffffff
+        && cnt++ < WINCE_DELETION_ATTEMPTS
+    ){
+       sqlite3_win32_sleep(100);  /* Wait a little before trying again */
+    }
+    sqlite3_free(pFile->zDeleteOnClose);
+  }
+#endif
+  if( rc ){
+    pFile->h = NULL;
+  }
+  OpenCounter(-1);
+  OSTRACE(("CLOSE pid=%lu, pFile=%p, file=%p, rc=%s\n",
+           osGetCurrentProcessId(), pFile, pFile->h, rc ? "ok" : "failed"));
+  return rc ? SQLITE_OK
+            : winLogError(SQLITE_IOERR_CLOSE, osGetLastError(),
+                          "winClose", pFile->zPath);
+}
+
+/*
+** Read data from a file into a buffer.  Return SQLITE_OK if all
+** bytes were read successfully and SQLITE_IOERR if anything goes
+** wrong.
+*/
+static int winRead(
+  sqlite3_file *id,          /* File to read from */
+  void *pBuf,                /* Write content into this buffer */
+  int amt,                   /* Number of bytes to read */
+  sqlite3_int64 offset       /* Begin reading at this offset */
+){
+#if !SQLITE_OS_WINCE && !defined(SQLITE_WIN32_NO_OVERLAPPED)
+  OVERLAPPED overlapped;          /* The offset for ReadFile. */
+#endif
+  winFile *pFile = (winFile*)id;  /* file handle */
+  DWORD nRead;                    /* Number of bytes actually read from file */
+  int nRetry = 0;                 /* Number of retrys */
+
+  assert( id!=0 );
+  assert( amt>0 );
+  assert( offset>=0 );
+  SimulateIOError(return SQLITE_IOERR_READ);
+  OSTRACE(("READ pid=%lu, pFile=%p, file=%p, buffer=%p, amount=%d, "
+           "offset=%lld, lock=%d\n", osGetCurrentProcessId(), pFile,
+           pFile->h, pBuf, amt, offset, pFile->locktype));
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  /* Deal with as much of this read request as possible by transferring
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt);
+      OSTRACE(("READ-MMAP pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+               osGetCurrentProcessId(), pFile, pFile->h));
+      return SQLITE_OK;
+    }else{
+      int nCopy = (int)(pFile->mmapSize - offset);
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+#endif
+
+#if SQLITE_OS_WINCE || defined(SQLITE_WIN32_NO_OVERLAPPED)
+  if( winSeekFile(pFile, offset) ){
+    OSTRACE(("READ pid=%lu, pFile=%p, file=%p, rc=SQLITE_FULL\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return SQLITE_FULL;
+  }
+  while( !osReadFile(pFile->h, pBuf, amt, &nRead, 0) ){
+#else
+  memset(&overlapped, 0, sizeof(OVERLAPPED));
+  overlapped.Offset = (LONG)(offset & 0xffffffff);
+  overlapped.OffsetHigh = (LONG)((offset>>32) & 0x7fffffff);
+  while( !osReadFile(pFile->h, pBuf, amt, &nRead, &overlapped) &&
+         osGetLastError()!=ERROR_HANDLE_EOF ){
+#endif
+    DWORD lastErrno;
+    if( winRetryIoerr(&nRetry, &lastErrno) ) continue;
+    pFile->lastErrno = lastErrno;
+    OSTRACE(("READ pid=%lu, pFile=%p, file=%p, rc=SQLITE_IOERR_READ\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return winLogError(SQLITE_IOERR_READ, pFile->lastErrno,
+                       "winRead", pFile->zPath);
+  }
+  winLogIoerr(nRetry, __LINE__);
+  if( nRead<(DWORD)amt ){
+    /* Unread parts of the buffer must be zero-filled */
+    memset(&((char*)pBuf)[nRead], 0, amt-nRead);
+    OSTRACE(("READ pid=%lu, pFile=%p, file=%p, rc=SQLITE_IOERR_SHORT_READ\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return SQLITE_IOERR_SHORT_READ;
+  }
+
+  OSTRACE(("READ pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFile, pFile->h));
+  return SQLITE_OK;
+}
+
+/*
+** Write data from a buffer into a file.  Return SQLITE_OK on success
+** or some other error code on failure.
+*/
+static int winWrite(
+  sqlite3_file *id,               /* File to write into */
+  const void *pBuf,               /* The bytes to be written */
+  int amt,                        /* Number of bytes to write */
+  sqlite3_int64 offset            /* Offset into the file to begin writing at */
+){
+  int rc = 0;                     /* True if error has occurred, else false */
+  winFile *pFile = (winFile*)id;  /* File handle */
+  int nRetry = 0;                 /* Number of retries */
+
+  assert( amt>0 );
+  assert( pFile );
+  SimulateIOError(return SQLITE_IOERR_WRITE);
+  SimulateDiskfullError(return SQLITE_FULL);
+
+  OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, buffer=%p, amount=%d, "
+           "offset=%lld, lock=%d\n", osGetCurrentProcessId(), pFile,
+           pFile->h, pBuf, amt, offset, pFile->locktype));
+
+#if defined(SQLITE_MMAP_READWRITE) && SQLITE_MAX_MMAP_SIZE>0
+  /* Deal with as much of this write request as possible by transferring
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt);
+      OSTRACE(("WRITE-MMAP pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+               osGetCurrentProcessId(), pFile, pFile->h));
+      return SQLITE_OK;
+    }else{
+      int nCopy = (int)(pFile->mmapSize - offset);
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+#endif
+
+#if SQLITE_OS_WINCE || defined(SQLITE_WIN32_NO_OVERLAPPED)
+  rc = winSeekFile(pFile, offset);
+  if( rc==0 ){
+#else
+  {
+#endif
+#if !SQLITE_OS_WINCE && !defined(SQLITE_WIN32_NO_OVERLAPPED)
+    OVERLAPPED overlapped;        /* The offset for WriteFile. */
+#endif
+    u8 *aRem = (u8 *)pBuf;        /* Data yet to be written */
+    int nRem = amt;               /* Number of bytes yet to be written */
+    DWORD nWrite;                 /* Bytes written by each WriteFile() call */
+    DWORD lastErrno = NO_ERROR;   /* Value returned by GetLastError() */
+
+#if !SQLITE_OS_WINCE && !defined(SQLITE_WIN32_NO_OVERLAPPED)
+    memset(&overlapped, 0, sizeof(OVERLAPPED));
+    overlapped.Offset = (LONG)(offset & 0xffffffff);
+    overlapped.OffsetHigh = (LONG)((offset>>32) & 0x7fffffff);
+#endif
+
+    while( nRem>0 ){
+#if SQLITE_OS_WINCE || defined(SQLITE_WIN32_NO_OVERLAPPED)
+      if( !osWriteFile(pFile->h, aRem, nRem, &nWrite, 0) ){
+#else
+      if( !osWriteFile(pFile->h, aRem, nRem, &nWrite, &overlapped) ){
+#endif
+        if( winRetryIoerr(&nRetry, &lastErrno) ) continue;
+        break;
+      }
+      assert( nWrite==0 || nWrite<=(DWORD)nRem );
+      if( nWrite==0 || nWrite>(DWORD)nRem ){
+        lastErrno = osGetLastError();
+        break;
+      }
+#if !SQLITE_OS_WINCE && !defined(SQLITE_WIN32_NO_OVERLAPPED)
+      offset += nWrite;
+      overlapped.Offset = (LONG)(offset & 0xffffffff);
+      overlapped.OffsetHigh = (LONG)((offset>>32) & 0x7fffffff);
+#endif
+      aRem += nWrite;
+      nRem -= nWrite;
+    }
+    if( nRem>0 ){
+      pFile->lastErrno = lastErrno;
+      rc = 1;
+    }
+  }
+
+  if( rc ){
+    if(   ( pFile->lastErrno==ERROR_HANDLE_DISK_FULL )
+       || ( pFile->lastErrno==ERROR_DISK_FULL )){
+      OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, rc=SQLITE_FULL\n",
+               osGetCurrentProcessId(), pFile, pFile->h));
+      return winLogError(SQLITE_FULL, pFile->lastErrno,
+                         "winWrite1", pFile->zPath);
+    }
+    OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, rc=SQLITE_IOERR_WRITE\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return winLogError(SQLITE_IOERR_WRITE, pFile->lastErrno,
+                       "winWrite2", pFile->zPath);
+  }else{
+    winLogIoerr(nRetry, __LINE__);
+  }
+  OSTRACE(("WRITE pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFile, pFile->h));
+  return SQLITE_OK;
+}
+
+/*
+** Truncate an open file to a specified size
+*/
+static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
+  winFile *pFile = (winFile*)id;  /* File handle object */
+  int rc = SQLITE_OK;             /* Return code for this function */
+  DWORD lastErrno;
+#if SQLITE_MAX_MMAP_SIZE>0
+  sqlite3_int64 oldMmapSize;
+  if( pFile->nFetchOut>0 ){
+    /* File truncation is a no-op if there are outstanding memory mapped
+    ** pages.  This is because truncating the file means temporarily unmapping
+    ** the file, and that might delete memory out from under existing cursors.
+    **
+    ** This can result in incremental vacuum not truncating the file,
+    ** if there is an active read cursor when the incremental vacuum occurs.
+    ** No real harm comes of this - the database file is not corrupted,
+    ** though some folks might complain that the file is bigger than it
+    ** needs to be.
+    **
+    ** The only feasible work-around is to defer the truncation until after
+    ** all references to memory-mapped content are closed.  That is doable,
+    ** but involves adding a few branches in the common write code path which
+    ** could slow down normal operations slightly.  Hence, we have decided for
+    ** now to simply make transactions a no-op if there are pending reads.  We
+    ** can maybe revisit this decision in the future.
+    */
+    return SQLITE_OK;
+  }
+#endif
+
+  assert( pFile );
+  SimulateIOError(return SQLITE_IOERR_TRUNCATE);
+  OSTRACE(("TRUNCATE pid=%lu, pFile=%p, file=%p, size=%lld, lock=%d\n",
+           osGetCurrentProcessId(), pFile, pFile->h, nByte, pFile->locktype));
+
+  /* If the user has configured a chunk-size for this file, truncate the
+  ** file so that it consists of an integer number of chunks (i.e. the
+  ** actual file size after the operation may be larger than the requested
+  ** size).
+  */
+  if( pFile->szChunk>0 ){
+    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
+  }
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFile->pMapRegion ){
+    oldMmapSize = pFile->mmapSize;
+  }else{
+    oldMmapSize = 0;
+  }
+  winUnmapfile(pFile);
+#endif
+
+  /* SetEndOfFile() returns non-zero when successful, or zero when it fails. */
+  if( winSeekFile(pFile, nByte) ){
+    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
+                     "winTruncate1", pFile->zPath);
+  }else if( 0==osSetEndOfFile(pFile->h) &&
+            ((lastErrno = osGetLastError())!=ERROR_USER_MAPPED_FILE) ){
+    pFile->lastErrno = lastErrno;
+    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
+                     "winTruncate2", pFile->zPath);
+  }
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( rc==SQLITE_OK && oldMmapSize>0 ){
+    if( oldMmapSize>nByte ){
+      winMapfile(pFile, -1);
+    }else{
+      winMapfile(pFile, oldMmapSize);
+    }
+  }
+#endif
+
+  OSTRACE(("TRUNCATE pid=%lu, pFile=%p, file=%p, rc=%s\n",
+           osGetCurrentProcessId(), pFile, pFile->h, sqlite3ErrName(rc)));
+  return rc;
+}
+
+#ifdef SQLITE_TEST
+/*
+** Count the number of fullsyncs and normal syncs.  This is used to test
+** that syncs and fullsyncs are occurring at the right times.
+*/
+SQLITE_API int sqlite3_sync_count = 0;
+SQLITE_API int sqlite3_fullsync_count = 0;
+#endif
+
+/*
+** Make sure all writes to a particular file are committed to disk.
+*/
+static int winSync(sqlite3_file *id, int flags){
+#ifndef SQLITE_NO_SYNC
+  /*
+  ** Used only when SQLITE_NO_SYNC is not defined.
+   */
+  BOOL rc;
+#endif
+#if !defined(NDEBUG) || !defined(SQLITE_NO_SYNC) || \
+    defined(SQLITE_HAVE_OS_TRACE)
+  /*
+  ** Used when SQLITE_NO_SYNC is not defined and by the assert() and/or
+  ** OSTRACE() macros.
+   */
+  winFile *pFile = (winFile*)id;
+#else
+  UNUSED_PARAMETER(id);
+#endif
+
+  assert( pFile );
+  /* Check that one of SQLITE_SYNC_NORMAL or FULL was passed */
+  assert((flags&0x0F)==SQLITE_SYNC_NORMAL
+      || (flags&0x0F)==SQLITE_SYNC_FULL
+  );
+
+  /* Unix cannot, but some systems may return SQLITE_FULL from here. This
+  ** line is to test that doing so does not cause any problems.
+  */
+  SimulateDiskfullError( return SQLITE_FULL );
+
+  OSTRACE(("SYNC pid=%lu, pFile=%p, file=%p, flags=%x, lock=%d\n",
+           osGetCurrentProcessId(), pFile, pFile->h, flags,
+           pFile->locktype));
+
+#ifndef SQLITE_TEST
+  UNUSED_PARAMETER(flags);
+#else
+  if( (flags&0x0F)==SQLITE_SYNC_FULL ){
+    sqlite3_fullsync_count++;
+  }
+  sqlite3_sync_count++;
+#endif
+
+  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
+  ** no-op
+  */
+#ifdef SQLITE_NO_SYNC
+  OSTRACE(("SYNC-NOP pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFile, pFile->h));
+  return SQLITE_OK;
+#else
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFile->pMapRegion ){
+    if( osFlushViewOfFile(pFile->pMapRegion, 0) ){
+      OSTRACE(("SYNC-MMAP pid=%lu, pFile=%p, pMapRegion=%p, "
+               "rc=SQLITE_OK\n", osGetCurrentProcessId(),
+               pFile, pFile->pMapRegion));
+    }else{
+      pFile->lastErrno = osGetLastError();
+      OSTRACE(("SYNC-MMAP pid=%lu, pFile=%p, pMapRegion=%p, "
+               "rc=SQLITE_IOERR_MMAP\n", osGetCurrentProcessId(),
+               pFile, pFile->pMapRegion));
+      return winLogError(SQLITE_IOERR_MMAP, pFile->lastErrno,
+                         "winSync1", pFile->zPath);
+    }
+  }
+#endif
+  rc = osFlushFileBuffers(pFile->h);
+  SimulateIOError( rc=FALSE );
+  if( rc ){
+    OSTRACE(("SYNC pid=%lu, pFile=%p, file=%p, rc=SQLITE_OK\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return SQLITE_OK;
+  }else{
+    pFile->lastErrno = osGetLastError();
+    OSTRACE(("SYNC pid=%lu, pFile=%p, file=%p, rc=SQLITE_IOERR_FSYNC\n",
+             osGetCurrentProcessId(), pFile, pFile->h));
+    return winLogError(SQLITE_IOERR_FSYNC, pFile->lastErrno,
+                       "winSync2", pFile->zPath);
+  }
+#endif
+}
+
+/*
+** Determine the current size of a file in bytes
+*/
+static int winFileSize(sqlite3_file *id, sqlite3_int64 *pSize){
+  winFile *pFile = (winFile*)id;
+  int rc = SQLITE_OK;
+
+  assert( id!=0 );
+  assert( pSize!=0 );
+  SimulateIOError(return SQLITE_IOERR_FSTAT);
+  OSTRACE(("SIZE file=%p, pSize=%p\n", pFile->h, pSize));
+
+#if SQLITE_OS_WINRT
+  {
+    FILE_STANDARD_INFO info;
+    if( osGetFileInformationByHandleEx(pFile->h, FileStandardInfo,
+                                     &info, sizeof(info)) ){
+      *pSize = info.EndOfFile.QuadPart;
+    }else{
+      pFile->lastErrno = osGetLastError();
+      rc = winLogError(SQLITE_IOERR_FSTAT, pFile->lastErrno,
+                       "winFileSize", pFile->zPath);
+    }
+  }
+#else
+  {
+    DWORD upperBits;
+    DWORD lowerBits;
+    DWORD lastErrno;
+
+    lowerBits = osGetFileSize(pFile->h, &upperBits);
+    *pSize = (((sqlite3_int64)upperBits)<<32) + lowerBits;
+    if(   (lowerBits == INVALID_FILE_SIZE)
+       && ((lastErrno = osGetLastError())!=NO_ERROR) ){
+      pFile->lastErrno = lastErrno;
+      rc = winLogError(SQLITE_IOERR_FSTAT, pFile->lastErrno,
+                       "winFileSize", pFile->zPath);
+    }
+  }
+#endif
+  OSTRACE(("SIZE file=%p, pSize=%p, *pSize=%lld, rc=%s\n",
+           pFile->h, pSize, *pSize, sqlite3ErrName(rc)));
+  return rc;
+}
+
+/*
+** LOCKFILE_FAIL_IMMEDIATELY is undefined on some Windows systems.
+*/
+#ifndef LOCKFILE_FAIL_IMMEDIATELY
+# define LOCKFILE_FAIL_IMMEDIATELY 1
+#endif
+
+#ifndef LOCKFILE_EXCLUSIVE_LOCK
+# define LOCKFILE_EXCLUSIVE_LOCK 2
+#endif
+
+/*
+** Historically, SQLite has used both the LockFile and LockFileEx functions.
+** When the LockFile function was used, it was always expected to fail
+** immediately if the lock could not be obtained.  Also, it always expected to
+** obtain an exclusive lock.  These flags are used with the LockFileEx function
+** and reflect those expectations; therefore, they should not be changed.
+*/
+#ifndef SQLITE_LOCKFILE_FLAGS
+# define SQLITE_LOCKFILE_FLAGS   (LOCKFILE_FAIL_IMMEDIATELY | \
+                                  LOCKFILE_EXCLUSIVE_LOCK)
+#endif
+
+/*
+** Currently, SQLite never calls the LockFileEx function without wanting the
+** call to fail immediately if the lock cannot be obtained.
+*/
+#ifndef SQLITE_LOCKFILEEX_FLAGS
+# define SQLITE_LOCKFILEEX_FLAGS (LOCKFILE_FAIL_IMMEDIATELY)
+#endif
+
+/*
+** Acquire a reader lock.
+** Different API routines are called depending on whether or not this
+** is Win9x or WinNT.
+*/
+static int winGetReadLock(winFile *pFile){
+  int res;
+  OSTRACE(("READ-LOCK file=%p, lock=%d\n", pFile->h, pFile->locktype));
+  if( osIsNT() ){
+#if SQLITE_OS_WINCE
+    /*
+    ** NOTE: Windows CE is handled differently here due its lack of the Win32
+    **       API LockFileEx.
+    */
+    res = winceLockFile(&pFile->h, SHARED_FIRST, 0, 1, 0);
+#else
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILEEX_FLAGS, SHARED_FIRST, 0,
+                      SHARED_SIZE, 0);
+#endif
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    int lk;
+    sqlite3_randomness(sizeof(lk), &lk);
+    pFile->sharedLockByte = (short)((lk & 0x7fffffff)%(SHARED_SIZE - 1));
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS,
+                      SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
+  }
+#endif
+  if( res == 0 ){
+    pFile->lastErrno = osGetLastError();
+    /* No need to log a failure to lock */
+  }
+  OSTRACE(("READ-LOCK file=%p, result=%d\n", pFile->h, res));
+  return res;
+}
+
+/*
+** Undo a readlock
+*/
+static int winUnlockReadLock(winFile *pFile){
+  int res;
+  DWORD lastErrno;
+  OSTRACE(("READ-UNLOCK file=%p, lock=%d\n", pFile->h, pFile->locktype));
+  if( osIsNT() ){
+    res = winUnlockFile(&pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    res = winUnlockFile(&pFile->h, SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
+  }
+#endif
+  if( res==0 && ((lastErrno = osGetLastError())!=ERROR_NOT_LOCKED) ){
+    pFile->lastErrno = lastErrno;
+    winLogError(SQLITE_IOERR_UNLOCK, pFile->lastErrno,
+                "winUnlockReadLock", pFile->zPath);
+  }
+  OSTRACE(("READ-UNLOCK file=%p, result=%d\n", pFile->h, res));
+  return res;
+}
+
+/*
+** Lock the file with the lock specified by parameter locktype - one
+** of the following:
+**
+**     (1) SHARED_LOCK
+**     (2) RESERVED_LOCK
+**     (3) PENDING_LOCK
+**     (4) EXCLUSIVE_LOCK
+**
+** Sometimes when requesting one lock state, additional lock states
+** are inserted in between.  The locking might fail on one of the later
+** transitions leaving the lock state different from what it started but
+** still short of its goal.  The following chart shows the allowed
+** transitions and the inserted intermediate states:
+**
+**    UNLOCKED -> SHARED
+**    SHARED -> RESERVED
+**    SHARED -> (PENDING) -> EXCLUSIVE
+**    RESERVED -> (PENDING) -> EXCLUSIVE
+**    PENDING -> EXCLUSIVE
+**
+** This routine will only increase a lock.  The winUnlock() routine
+** erases all locks at once and returns us immediately to locking level 0.
+** It is not possible to lower the locking level one step at a time.  You
+** must go straight to locking level 0.
+*/
+static int winLock(sqlite3_file *id, int locktype){
+  int rc = SQLITE_OK;    /* Return code from subroutines */
+  int res = 1;           /* Result of a Windows lock call */
+  int newLocktype;       /* Set pFile->locktype to this value before exiting */
+  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
+  winFile *pFile = (winFile*)id;
+  DWORD lastErrno = NO_ERROR;
+
+  assert( id!=0 );
+  OSTRACE(("LOCK file=%p, oldLock=%d(%d), newLock=%d\n",
+           pFile->h, pFile->locktype, pFile->sharedLockByte, locktype));
+
+  /* If there is already a lock of this type or more restrictive on the
+  ** OsFile, do nothing. Don't use the end_lock: exit path, as
+  ** sqlite3OsEnterMutex() hasn't been called yet.
+  */
+  if( pFile->locktype>=locktype ){
+    OSTRACE(("LOCK-HELD file=%p, rc=SQLITE_OK\n", pFile->h));
+    return SQLITE_OK;
+  }
+
+  /* Do not allow any kind of write-lock on a read-only database
+  */
+  if( (pFile->ctrlFlags & WINFILE_RDONLY)!=0 && locktype>=RESERVED_LOCK ){
+    return SQLITE_IOERR_LOCK;
+  }
+
+  /* Make sure the locking sequence is correct
+  */
+  assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
+  assert( locktype!=PENDING_LOCK );
+  assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
+
+  /* Lock the PENDING_LOCK byte if we need to acquire a PENDING lock or
+  ** a SHARED lock.  If we are acquiring a SHARED lock, the acquisition of
+  ** the PENDING_LOCK byte is temporary.
+  */
+  newLocktype = pFile->locktype;
+  if( pFile->locktype==NO_LOCK
+   || (locktype==EXCLUSIVE_LOCK && pFile->locktype<=RESERVED_LOCK)
+  ){
+    int cnt = 3;
+    while( cnt-->0 && (res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS,
+                                         PENDING_BYTE, 0, 1, 0))==0 ){
+      /* Try 3 times to get the pending lock.  This is needed to work
+      ** around problems caused by indexing and/or anti-virus software on
+      ** Windows systems.
+      ** If you are using this code as a model for alternative VFSes, do not
+      ** copy this retry logic.  It is a hack intended for Windows only.
+      */
+      lastErrno = osGetLastError();
+      OSTRACE(("LOCK-PENDING-FAIL file=%p, count=%d, result=%d\n",
+               pFile->h, cnt, res));
+      if( lastErrno==ERROR_INVALID_HANDLE ){
+        pFile->lastErrno = lastErrno;
+        rc = SQLITE_IOERR_LOCK;
+        OSTRACE(("LOCK-FAIL file=%p, count=%d, rc=%s\n",
+                 pFile->h, cnt, sqlite3ErrName(rc)));
+        return rc;
+      }
+      if( cnt ) sqlite3_win32_sleep(1);
+    }
+    gotPendingLock = res;
+    if( !res ){
+      lastErrno = osGetLastError();
+    }
+  }
+
+  /* Acquire a shared lock
+  */
+  if( locktype==SHARED_LOCK && res ){
+    assert( pFile->locktype==NO_LOCK );
+    res = winGetReadLock(pFile);
+    if( res ){
+      newLocktype = SHARED_LOCK;
+    }else{
+      lastErrno = osGetLastError();
+    }
+  }
+
+  /* Acquire a RESERVED lock
+  */
+  if( locktype==RESERVED_LOCK && res ){
+    assert( pFile->locktype==SHARED_LOCK );
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS, RESERVED_BYTE, 0, 1, 0);
+    if( res ){
+      newLocktype = RESERVED_LOCK;
+    }else{
+      lastErrno = osGetLastError();
+    }
+  }
+
+  /* Acquire a PENDING lock
+  */
+  if( locktype==EXCLUSIVE_LOCK && res ){
+    newLocktype = PENDING_LOCK;
+    gotPendingLock = 0;
+  }
+
+  /* Acquire an EXCLUSIVE lock
+  */
+  if( locktype==EXCLUSIVE_LOCK && res ){
+    assert( pFile->locktype>=SHARED_LOCK );
+    (void)winUnlockReadLock(pFile);
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILE_FLAGS, SHARED_FIRST, 0,
+                      SHARED_SIZE, 0);
+    if( res ){
+      newLocktype = EXCLUSIVE_LOCK;
+    }else{
+      lastErrno = osGetLastError();
+      winGetReadLock(pFile);
+    }
+  }
+
+  /* If we are holding a PENDING lock that ought to be released, then
+  ** release it now.
+  */
+  if( gotPendingLock && locktype==SHARED_LOCK ){
+    winUnlockFile(&pFile->h, PENDING_BYTE, 0, 1, 0);
+  }
+
+  /* Update the state of the lock has held in the file descriptor then
+  ** return the appropriate result code.
+  */
+  if( res ){
+    rc = SQLITE_OK;
+  }else{
+    pFile->lastErrno = lastErrno;
+    rc = SQLITE_BUSY;
+    OSTRACE(("LOCK-FAIL file=%p, wanted=%d, got=%d\n",
+             pFile->h, locktype, newLocktype));
+  }
+  pFile->locktype = (u8)newLocktype;
+  OSTRACE(("LOCK file=%p, lock=%d, rc=%s\n",
+           pFile->h, pFile->locktype, sqlite3ErrName(rc)));
+  return rc;
+}
+
+/*
+** This routine checks if there is a RESERVED lock held on the specified
+** file by this or any other process. If such a lock is held, return
+** non-zero, otherwise zero.
+*/
+static int winCheckReservedLock(sqlite3_file *id, int *pResOut){
+  int res;
+  winFile *pFile = (winFile*)id;
+
+  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
+  OSTRACE(("TEST-WR-LOCK file=%p, pResOut=%p\n", pFile->h, pResOut));
+
+  assert( id!=0 );
+  if( pFile->locktype>=RESERVED_LOCK ){
+    res = 1;
+    OSTRACE(("TEST-WR-LOCK file=%p, result=%d (local)\n", pFile->h, res));
+  }else{
+    res = winLockFile(&pFile->h, SQLITE_LOCKFILEEX_FLAGS,RESERVED_BYTE,0,1,0);
+    if( res ){
+      winUnlockFile(&pFile->h, RESERVED_BYTE, 0, 1, 0);
+    }
+    res = !res;
+    OSTRACE(("TEST-WR-LOCK file=%p, result=%d (remote)\n", pFile->h, res));
+  }
+  *pResOut = res;
+  OSTRACE(("TEST-WR-LOCK file=%p, pResOut=%p, *pResOut=%d, rc=SQLITE_OK\n",
+           pFile->h, pResOut, *pResOut));
+  return SQLITE_OK;
+}
+
+/*
+** Lower the locking level on file descriptor id to locktype.  locktype
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+**
+** It is not possible for this routine to fail if the second argument
+** is NO_LOCK.  If the second argument is SHARED_LOCK then this routine
+** might return SQLITE_IOERR;
+*/
+static int winUnlock(sqlite3_file *id, int locktype){
+  int type;
+  winFile *pFile = (winFile*)id;
+  int rc = SQLITE_OK;
+  assert( pFile!=0 );
+  assert( locktype<=SHARED_LOCK );
+  OSTRACE(("UNLOCK file=%p, oldLock=%d(%d), newLock=%d\n",
+           pFile->h, pFile->locktype, pFile->sharedLockByte, locktype));
+  type = pFile->locktype;
+  if( type>=EXCLUSIVE_LOCK ){
+    winUnlockFile(&pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
+    if( locktype==SHARED_LOCK && !winGetReadLock(pFile) ){
+      /* This should never happen.  We should always be able to
+      ** reacquire the read lock */
+      rc = winLogError(SQLITE_IOERR_UNLOCK, osGetLastError(),
+                       "winUnlock", pFile->zPath);
+    }
+  }
+  if( type>=RESERVED_LOCK ){
+    winUnlockFile(&pFile->h, RESERVED_BYTE, 0, 1, 0);
+  }
+  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
+    winUnlockReadLock(pFile);
+  }
+  if( type>=PENDING_LOCK ){
+    winUnlockFile(&pFile->h, PENDING_BYTE, 0, 1, 0);
+  }
+  pFile->locktype = (u8)locktype;
+  OSTRACE(("UNLOCK file=%p, lock=%d, rc=%s\n",
+           pFile->h, pFile->locktype, sqlite3ErrName(rc)));
+  return rc;
+}
+
+/******************************************************************************
+****************************** No-op Locking **********************************
+**
+** Of the various locking implementations available, this is by far the
+** simplest:  locking is ignored.  No attempt is made to lock the database
+** file for reading or writing.
+**
+** This locking mode is appropriate for use on read-only databases
+** (ex: databases that are burned into CD-ROM, for example.)  It can
+** also be used if the application employs some external mechanism to
+** prevent simultaneous access of the same database by two or more
+** database connections.  But there is a serious risk of database
+** corruption if this locking mode is used in situations where multiple
+** database connections are accessing the same database file at the same
+** time and one or more of those connections are writing.
+*/
+
+static int winNolockLock(sqlite3_file *id, int locktype){
+  UNUSED_PARAMETER(id);
+  UNUSED_PARAMETER(locktype);
+  return SQLITE_OK;
+}
+
+static int winNolockCheckReservedLock(sqlite3_file *id, int *pResOut){
+  UNUSED_PARAMETER(id);
+  UNUSED_PARAMETER(pResOut);
+  return SQLITE_OK;
+}
+
+static int winNolockUnlock(sqlite3_file *id, int locktype){
+  UNUSED_PARAMETER(id);
+  UNUSED_PARAMETER(locktype);
+  return SQLITE_OK;
+}
+
+/******************* End of the no-op lock implementation *********************
+******************************************************************************/
+
+/*
+** If *pArg is initially negative then this is a query.  Set *pArg to
+** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
+**
+** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
+*/
+static void winModeBit(winFile *pFile, unsigned char mask, int *pArg){
+  if( *pArg<0 ){
+    *pArg = (pFile->ctrlFlags & mask)!=0;
+  }else if( (*pArg)==0 ){
+    pFile->ctrlFlags &= ~mask;
+  }else{
+    pFile->ctrlFlags |= mask;
+  }
+}
+
+/* Forward references to VFS helper methods used for temporary files */
+static int winGetTempname(sqlite3_vfs *, char **);
+static int winIsDir(const void *);
+static BOOL winIsLongPathPrefix(const char *);
+static BOOL winIsDriveLetterAndColon(const char *);
+
+/*
+** Control and query of the open file handle.
+*/
+static int winFileControl(sqlite3_file *id, int op, void *pArg){
+  winFile *pFile = (winFile*)id;
+  OSTRACE(("FCNTL file=%p, op=%d, pArg=%p\n", pFile->h, op, pArg));
+  switch( op ){
+    case SQLITE_FCNTL_LOCKSTATE: {
+      *(int*)pArg = pFile->locktype;
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_LAST_ERRNO: {
+      *(int*)pArg = (int)pFile->lastErrno;
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_CHUNK_SIZE: {
+      pFile->szChunk = *(int *)pArg;
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_SIZE_HINT: {
+      if( pFile->szChunk>0 ){
+        sqlite3_int64 oldSz;
+        int rc = winFileSize(id, &oldSz);
+        if( rc==SQLITE_OK ){
+          sqlite3_int64 newSz = *(sqlite3_int64*)pArg;
+          if( newSz>oldSz ){
+            SimulateIOErrorBenign(1);
+            rc = winTruncate(id, newSz);
+            SimulateIOErrorBenign(0);
+          }
+        }
+        OSTRACE(("FCNTL file=%p, rc=%s\n", pFile->h, sqlite3ErrName(rc)));
+        return rc;
+      }
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_PERSIST_WAL: {
+      winModeBit(pFile, WINFILE_PERSIST_WAL, (int*)pArg);
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
+      winModeBit(pFile, WINFILE_PSOW, (int*)pArg);
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_VFSNAME: {
+      *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName);
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_WIN32_AV_RETRY: {
+      int *a = (int*)pArg;
+      if( a[0]>0 ){
+        winIoerrRetry = a[0];
+      }else{
+        a[0] = winIoerrRetry;
+      }
+      if( a[1]>0 ){
+        winIoerrRetryDelay = a[1];
+      }else{
+        a[1] = winIoerrRetryDelay;
+      }
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_WIN32_GET_HANDLE: {
+      LPHANDLE phFile = (LPHANDLE)pArg;
+      *phFile = pFile->h;
+      OSTRACE(("FCNTL file=%p, rc=SQLITE_OK\n", pFile->h));
+      return SQLITE_OK;
+    }
+#ifdef SQLITE_TEST
+    case SQLITE_FCNTL_WIN32_SET_HANDLE: {
+      LPHANDLE phFile = (LPHANDLE)pArg;
+      HANDLE hOldFile = pFile->h;
+      pFile->h = *phFile;
+      *phFile = hOldFile;
+      OSTRACE(("FCNTL oldFile=%p, newFile=%p, rc=SQLITE_OK\n",
+               hOldFile, pFile->h));
+      return SQLITE_OK;
+    }
+#endif
+    case SQLITE_FCNTL_NULL_IO: {
+      (void)osCloseHandle(pFile->h);
+      pFile->h = NULL;
+      return SQLITE_OK;
+    }
+    case SQLITE_FCNTL_TEMPFILENAME: {
+      char *zTFile = 0;
+      int rc = winGetTempname(pFile->pVfs, &zTFile);
+      if( rc==SQLITE_OK ){
+        *(char**)pArg = zTFile;
+      }
+      OSTRACE(("FCNTL file=%p, rc=%s\n", pFile->h, sqlite3ErrName(rc)));
+      return rc;
+    }
+#if SQLITE_MAX_MMAP_SIZE>0
+    case SQLITE_FCNTL_MMAP_SIZE: {
+      i64 newLimit = *(i64*)pArg;
+      int rc = SQLITE_OK;
+      if( newLimit>sqlite3GlobalConfig.mxMmap ){
+        newLimit = sqlite3GlobalConfig.mxMmap;
+      }
+
+      /* The value of newLimit may be eventually cast to (SIZE_T) and passed
+      ** to MapViewOfFile(). Restrict its value to 2GB if (SIZE_T) is not at
+      ** least a 64-bit type. */
+      if( newLimit>0 && sizeof(SIZE_T)<8 ){
+        newLimit = (newLimit & 0x7FFFFFFF);
+      }
+
+      *(i64*)pArg = pFile->mmapSizeMax;
+      if( newLimit>=0 && newLimit!=pFile->mmapSizeMax && pFile->nFetchOut==0 ){
+        pFile->mmapSizeMax = newLimit;
+        if( pFile->mmapSize>0 ){
+          winUnmapfile(pFile);
+          rc = winMapfile(pFile, -1);
+        }
+      }
+      OSTRACE(("FCNTL file=%p, rc=%s\n", pFile->h, sqlite3ErrName(rc)));
+      return rc;
+    }
+#endif
+  }
+  OSTRACE(("FCNTL file=%p, rc=SQLITE_NOTFOUND\n", pFile->h));
+  return SQLITE_NOTFOUND;
+}
+
+/*
+** Return the sector size in bytes of the underlying block device for
+** the specified file. This is almost always 512 bytes, but may be
+** larger for some devices.
+**
+** SQLite code assumes this function cannot fail. It also assumes that
+** if two files are created in the same file-system directory (i.e.
+** a database and its journal file) that the sector size will be the
+** same for both.
+*/
+static int winSectorSize(sqlite3_file *id){
+  (void)id;
+  return SQLITE_DEFAULT_SECTOR_SIZE;
+}
+
+/*
+** Return a vector of device characteristics.
+*/
+static int winDeviceCharacteristics(sqlite3_file *id){
+  winFile *p = (winFile*)id;
+  return SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN | SQLITE_IOCAP_SUBPAGE_READ |
+         ((p->ctrlFlags & WINFILE_PSOW)?SQLITE_IOCAP_POWERSAFE_OVERWRITE:0);
+}
+
+/*
+** Windows will only let you create file view mappings
+** on allocation size granularity boundaries.
+** During sqlite3_os_init() we do a GetSystemInfo()
+** to get the granularity size.
+*/
+static SYSTEM_INFO winSysInfo;
+
+#ifndef SQLITE_OMIT_WAL
+
+/*
+** Helper functions to obtain and relinquish the global mutex. The
+** global mutex is used to protect the winLockInfo objects used by
+** this file, all of which may be shared by multiple threads.
+**
+** Function winShmMutexHeld() is used to assert() that the global mutex
+** is held when required. This function is only used as part of assert()
+** statements. e.g.
+**
+**   winShmEnterMutex()
+**     assert( winShmMutexHeld() );
+**   winShmLeaveMutex()
+*/
+static sqlite3_mutex *winBigLock = 0;
+static void winShmEnterMutex(void){
+  sqlite3_mutex_enter(winBigLock);
+}
+static void winShmLeaveMutex(void){
+  sqlite3_mutex_leave(winBigLock);
+}
+#ifndef NDEBUG
+static int winShmMutexHeld(void) {
+  return sqlite3_mutex_held(winBigLock);
+}
+#endif
+
+/*
+** Object used to represent a single file opened and mmapped to provide
+** shared memory.  When multiple threads all reference the same
+** log-summary, each thread has its own winFile object, but they all
+** point to a single instance of this object.  In other words, each
+** log-summary is opened only once per process.
+**
+** winShmMutexHeld() must be true when creating or destroying
+** this object or while reading or writing the following fields:
+**
+**      nRef
+**      pNext
+**
+** The following fields are read-only after the object is created:
+**
+**      fid
+**      zFilename
+**
+** Either winShmNode.mutex must be held or winShmNode.nRef==0 and
+** winShmMutexHeld() is true when reading or writing any other field
+** in this structure.
+**
+*/
+struct winShmNode {
+  sqlite3_mutex *mutex;      /* Mutex to access this object */
+  char *zFilename;           /* Name of the file */
+  winFile hFile;             /* File handle from winOpen */
+
+  int szRegion;              /* Size of shared-memory regions */
+  int nRegion;               /* Size of array apRegion */
+  u8 isReadonly;             /* True if read-only */
+  u8 isUnlocked;             /* True if no DMS lock held */
+
+  struct ShmRegion {
+    HANDLE hMap;             /* File handle from CreateFileMapping */
+    void *pMap;
+  } *aRegion;
+  DWORD lastErrno;           /* The Windows errno from the last I/O error */
+
+  int nRef;                  /* Number of winShm objects pointing to this */
+  winShm *pFirst;            /* All winShm objects pointing to this */
+  winShmNode *pNext;         /* Next in list of all winShmNode objects */
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+  u8 nextShmId;              /* Next available winShm.id value */
+#endif
+};
+
+/*
+** A global array of all winShmNode objects.
+**
+** The winShmMutexHeld() must be true while reading or writing this list.
+*/
+static winShmNode *winShmNodeList = 0;
+
+/*
+** Structure used internally by this VFS to record the state of an
+** open shared memory connection.
+**
+** The following fields are initialized when this object is created and
+** are read-only thereafter:
+**
+**    winShm.pShmNode
+**    winShm.id
+**
+** All other fields are read/write.  The winShm.pShmNode->mutex must be held
+** while accessing any read/write fields.
+*/
+struct winShm {
+  winShmNode *pShmNode;      /* The underlying winShmNode object */
+  winShm *pNext;             /* Next winShm with the same winShmNode */
+  u8 hasMutex;               /* True if holding the winShmNode mutex */
+  u16 sharedMask;            /* Mask of shared locks held */
+  u16 exclMask;              /* Mask of exclusive locks held */
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+  u8 id;                     /* Id of this connection with its winShmNode */
+#endif
+};
+
+/*
+** Constants used for locking
+*/
+#define WIN_SHM_BASE   ((22+SQLITE_SHM_NLOCK)*4)        /* first lock byte */
+#define WIN_SHM_DMS    (WIN_SHM_BASE+SQLITE_SHM_NLOCK)  /* deadman switch */
+
+/*
+** Apply advisory locks for all n bytes beginning at ofst.
+*/
+#define WINSHM_UNLCK  1
+#define WINSHM_RDLCK  2
+#define WINSHM_WRLCK  3
+static int winShmSystemLock(
+  winShmNode *pFile,    /* Apply locks to this open shared-memory segment */
+  int lockType,         /* WINSHM_UNLCK, WINSHM_RDLCK, or WINSHM_WRLCK */
+  int ofst,             /* Offset to first byte to be locked/unlocked */
+  int nByte             /* Number of bytes to lock or unlock */
+){
+  int rc = 0;           /* Result code form Lock/UnlockFileEx() */
+
+  /* Access to the winShmNode object is serialized by the caller */
+  assert( pFile->nRef==0 || sqlite3_mutex_held(pFile->mutex) );
+
+  OSTRACE(("SHM-LOCK file=%p, lock=%d, offset=%d, size=%d\n",
+           pFile->hFile.h, lockType, ofst, nByte));
+
+  /* Release/Acquire the system-level lock */
+  if( lockType==WINSHM_UNLCK ){
+    rc = winUnlockFile(&pFile->hFile.h, ofst, 0, nByte, 0);
+  }else{
+    /* Initialize the locking parameters */
+    DWORD dwFlags = LOCKFILE_FAIL_IMMEDIATELY;
+    if( lockType == WINSHM_WRLCK ) dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;
+    rc = winLockFile(&pFile->hFile.h, dwFlags, ofst, 0, nByte, 0);
+  }
+
+  if( rc!= 0 ){
+    rc = SQLITE_OK;
+  }else{
+    pFile->lastErrno =  osGetLastError();
+    rc = SQLITE_BUSY;
+  }
+
+  OSTRACE(("SHM-LOCK file=%p, func=%s, errno=%lu, rc=%s\n",
+           pFile->hFile.h, (lockType == WINSHM_UNLCK) ? "winUnlockFile" :
+           "winLockFile", pFile->lastErrno, sqlite3ErrName(rc)));
+
+  return rc;
+}
+
+/* Forward references to VFS methods */
+static int winOpen(sqlite3_vfs*,const char*,sqlite3_file*,int,int*);
+static int winDelete(sqlite3_vfs *,const char*,int);
+
+/*
+** Purge the winShmNodeList list of all entries with winShmNode.nRef==0.
+**
+** This is not a VFS shared-memory method; it is a utility function called
+** by VFS shared-memory methods.
+*/
+static void winShmPurge(sqlite3_vfs *pVfs, int deleteFlag){
+  winShmNode **pp;
+  winShmNode *p;
+  assert( winShmMutexHeld() );
+  OSTRACE(("SHM-PURGE pid=%lu, deleteFlag=%d\n",
+           osGetCurrentProcessId(), deleteFlag));
+  pp = &winShmNodeList;
+  while( (p = *pp)!=0 ){
+    if( p->nRef==0 ){
+      int i;
+      if( p->mutex ){ sqlite3_mutex_free(p->mutex); }
+      for(i=0; i<p->nRegion; i++){
+        BOOL bRc = osUnmapViewOfFile(p->aRegion[i].pMap);
+        OSTRACE(("SHM-PURGE-UNMAP pid=%lu, region=%d, rc=%s\n",
+                 osGetCurrentProcessId(), i, bRc ? "ok" : "failed"));
+        UNUSED_VARIABLE_VALUE(bRc);
+        bRc = osCloseHandle(p->aRegion[i].hMap);
+        OSTRACE(("SHM-PURGE-CLOSE pid=%lu, region=%d, rc=%s\n",
+                 osGetCurrentProcessId(), i, bRc ? "ok" : "failed"));
+        UNUSED_VARIABLE_VALUE(bRc);
+      }
+      if( p->hFile.h!=NULL && p->hFile.h!=INVALID_HANDLE_VALUE ){
+        SimulateIOErrorBenign(1);
+        winClose((sqlite3_file *)&p->hFile);
+        SimulateIOErrorBenign(0);
+      }
+      if( deleteFlag ){
+        SimulateIOErrorBenign(1);
+        sqlite3BeginBenignMalloc();
+        winDelete(pVfs, p->zFilename, 0);
+        sqlite3EndBenignMalloc();
+        SimulateIOErrorBenign(0);
+      }
+      *pp = p->pNext;
+      sqlite3_free(p->aRegion);
+      sqlite3_free(p);
+    }else{
+      pp = &p->pNext;
+    }
+  }
+}
+
+/*
+** The DMS lock has not yet been taken on shm file pShmNode. Attempt to
+** take it now. Return SQLITE_OK if successful, or an SQLite error
+** code otherwise.
+**
+** If the DMS cannot be locked because this is a readonly_shm=1
+** connection and no other process already holds a lock, return
+** SQLITE_READONLY_CANTINIT and set pShmNode->isUnlocked=1.
+*/
+static int winLockSharedMemory(winShmNode *pShmNode){
+  int rc = winShmSystemLock(pShmNode, WINSHM_WRLCK, WIN_SHM_DMS, 1);
+
+  if( rc==SQLITE_OK ){
+    if( pShmNode->isReadonly ){
+      pShmNode->isUnlocked = 1;
+      winShmSystemLock(pShmNode, WINSHM_UNLCK, WIN_SHM_DMS, 1);
+      return SQLITE_READONLY_CANTINIT;
+    }else if( winTruncate((sqlite3_file*)&pShmNode->hFile, 0) ){
+      winShmSystemLock(pShmNode, WINSHM_UNLCK, WIN_SHM_DMS, 1);
+      return winLogError(SQLITE_IOERR_SHMOPEN, osGetLastError(),
+                         "winLockSharedMemory", pShmNode->zFilename);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    winShmSystemLock(pShmNode, WINSHM_UNLCK, WIN_SHM_DMS, 1);
+  }
+
+  return winShmSystemLock(pShmNode, WINSHM_RDLCK, WIN_SHM_DMS, 1);
+}
+
+/*
+** Open the shared-memory area associated with database file pDbFd.
+**
+** When opening a new shared-memory file, if no other instances of that
+** file are currently open, in this process or in other processes, then
+** the file must be truncated to zero length or have its header cleared.
+*/
+static int winOpenSharedMemory(winFile *pDbFd){
+  struct winShm *p;                  /* The connection to be opened */
+  winShmNode *pShmNode = 0;          /* The underlying mmapped file */
+  int rc = SQLITE_OK;                /* Result code */
+  winShmNode *pNew;                  /* Newly allocated winShmNode */
+  int nName;                         /* Size of zName in bytes */
+
+  assert( pDbFd->pShm==0 );    /* Not previously opened */
+
+  /* Allocate space for the new sqlite3_shm object.  Also speculatively
+  ** allocate space for a new winShmNode and filename.
+  */
+  p = sqlite3MallocZero( sizeof(*p) );
+  if( p==0 ) return SQLITE_IOERR_NOMEM_BKPT;
+  nName = sqlite3Strlen30(pDbFd->zPath);
+  pNew = sqlite3MallocZero( sizeof(*pShmNode) + nName + 17 );
+  if( pNew==0 ){
+    sqlite3_free(p);
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+  pNew->zFilename = (char*)&pNew[1];
+  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
+  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename);
+
+  /* Look to see if there is an existing winShmNode that can be used.
+  ** If no matching winShmNode currently exists, create a new one.
+  */
+  winShmEnterMutex();
+  for(pShmNode = winShmNodeList; pShmNode; pShmNode=pShmNode->pNext){
+    /* TBD need to come up with better match here.  Perhaps
+    ** use FILE_ID_BOTH_DIR_INFO Structure.
+    */
+    if( sqlite3StrICmp(pShmNode->zFilename, pNew->zFilename)==0 ) break;
+  }
+  if( pShmNode ){
+    sqlite3_free(pNew);
+  }else{
+    int inFlags = SQLITE_OPEN_WAL;
+    int outFlags = 0;
+
+    pShmNode = pNew;
+    pNew = 0;
+    ((winFile*)(&pShmNode->hFile))->h = INVALID_HANDLE_VALUE;
+    pShmNode->pNext = winShmNodeList;
+    winShmNodeList = pShmNode;
+
+    if( sqlite3GlobalConfig.bCoreMutex ){
+      pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+      if( pShmNode->mutex==0 ){
+        rc = SQLITE_IOERR_NOMEM_BKPT;
+        goto shm_open_err;
+      }
+    }
+
+    if( 0==sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){
+      inFlags |= SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE;
+    }else{
+      inFlags |= SQLITE_OPEN_READONLY;
+    }
+    rc = winOpen(pDbFd->pVfs, pShmNode->zFilename,
+                 (sqlite3_file*)&pShmNode->hFile,
+                 inFlags, &outFlags);
+    if( rc!=SQLITE_OK ){
+      rc = winLogError(rc, osGetLastError(), "winOpenShm",
+                       pShmNode->zFilename);
+      goto shm_open_err;
+    }
+    if( outFlags==SQLITE_OPEN_READONLY ) pShmNode->isReadonly = 1;
+
+    rc = winLockSharedMemory(pShmNode);
+    if( rc!=SQLITE_OK && rc!=SQLITE_READONLY_CANTINIT ) goto shm_open_err;
+  }
+
+  /* Make the new connection a child of the winShmNode */
+  p->pShmNode = pShmNode;
+#if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
+  p->id = pShmNode->nextShmId++;
+#endif
+  pShmNode->nRef++;
+  pDbFd->pShm = p;
+  winShmLeaveMutex();
+
+  /* The reference count on pShmNode has already been incremented under
+  ** the cover of the winShmEnterMutex() mutex and the pointer from the
+  ** new (struct winShm) object to the pShmNode has been set. All that is
+  ** left to do is to link the new object into the linked list starting
+  ** at pShmNode->pFirst. This must be done while holding the pShmNode->mutex
+  ** mutex.
+  */
+  sqlite3_mutex_enter(pShmNode->mutex);
+  p->pNext = pShmNode->pFirst;
+  pShmNode->pFirst = p;
+  sqlite3_mutex_leave(pShmNode->mutex);
+  return rc;
+
+  /* Jump here on any error */
+shm_open_err:
+  winShmSystemLock(pShmNode, WINSHM_UNLCK, WIN_SHM_DMS, 1);
+  winShmPurge(pDbFd->pVfs, 0);      /* This call frees pShmNode if required */
+  sqlite3_free(p);
+  sqlite3_free(pNew);
+  winShmLeaveMutex();
+  return rc;
+}
+
+/*
+** Close a connection to shared-memory.  Delete the underlying
+** storage if deleteFlag is true.
+*/
+static int winShmUnmap(
+  sqlite3_file *fd,          /* Database holding shared memory */
+  int deleteFlag             /* Delete after closing if true */
+){
+  winFile *pDbFd;       /* Database holding shared-memory */
+  winShm *p;            /* The connection to be closed */
+  winShmNode *pShmNode; /* The underlying shared-memory file */
+  winShm **pp;          /* For looping over sibling connections */
+
+  pDbFd = (winFile*)fd;
+  p = pDbFd->pShm;
+  if( p==0 ) return SQLITE_OK;
+  pShmNode = p->pShmNode;
+
+  /* Remove connection p from the set of connections associated
+  ** with pShmNode */
+  sqlite3_mutex_enter(pShmNode->mutex);
+  for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
+  *pp = p->pNext;
+
+  /* Free the connection p */
+  sqlite3_free(p);
+  pDbFd->pShm = 0;
+  sqlite3_mutex_leave(pShmNode->mutex);
+
+  /* If pShmNode->nRef has reached 0, then close the underlying
+  ** shared-memory file, too */
+  winShmEnterMutex();
+  assert( pShmNode->nRef>0 );
+  pShmNode->nRef--;
+  if( pShmNode->nRef==0 ){
+    winShmPurge(pDbFd->pVfs, deleteFlag);
+  }
+  winShmLeaveMutex();
+
+  return SQLITE_OK;
+}
+
+/*
+** Change the lock state for a shared-memory segment.
+*/
+static int winShmLock(
+  sqlite3_file *fd,          /* Database file holding the shared memory */
+  int ofst,                  /* First lock to acquire or release */
+  int n,                     /* Number of locks to acquire or release */
+  int flags                  /* What to do with the lock */
+){
+  winFile *pDbFd = (winFile*)fd;        /* Connection holding shared memory */
+  winShm *p = pDbFd->pShm;              /* The shared memory being locked */
+  winShm *pX;                           /* For looping over all siblings */
+  winShmNode *pShmNode;
+  int rc = SQLITE_OK;                   /* Result code */
+  u16 mask;                             /* Mask of locks to take or release */
+
+  if( p==0 ) return SQLITE_IOERR_SHMLOCK;
+  pShmNode = p->pShmNode;
+  if( NEVER(pShmNode==0) ) return SQLITE_IOERR_SHMLOCK;
+
+  assert( ofst>=0 && ofst+n<=SQLITE_SHM_NLOCK );
+  assert( n>=1 );
+  assert( flags==(SQLITE_SHM_LOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED)
+       || flags==(SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE) );
+  assert( n==1 || (flags & SQLITE_SHM_EXCLUSIVE)!=0 );
+
+  mask = (u16)((1U<<(ofst+n)) - (1U<<ofst));
+  assert( n>1 || mask==(1<<ofst) );
+  sqlite3_mutex_enter(pShmNode->mutex);
+  if( flags & SQLITE_SHM_UNLOCK ){
+    u16 allMask = 0; /* Mask of locks held by siblings */
+
+    /* See if any siblings hold this same lock */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( pX==p ) continue;
+      assert( (pX->exclMask & (p->exclMask|p->sharedMask))==0 );
+      allMask |= pX->sharedMask;
+    }
+
+    /* Unlock the system-level locks */
+    if( (mask & allMask)==0 ){
+      rc = winShmSystemLock(pShmNode, WINSHM_UNLCK, ofst+WIN_SHM_BASE, n);
+    }else{
+      rc = SQLITE_OK;
+    }
+
+    /* Undo the local locks */
+    if( rc==SQLITE_OK ){
+      p->exclMask &= ~mask;
+      p->sharedMask &= ~mask;
+    }
+  }else if( flags & SQLITE_SHM_SHARED ){
+    u16 allShared = 0;  /* Union of locks held by connections other than "p" */
+
+    /* Find out which shared locks are already held by sibling connections.
+    ** If any sibling already holds an exclusive lock, go ahead and return
+    ** SQLITE_BUSY.
+    */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( (pX->exclMask & mask)!=0 ){
+        rc = SQLITE_BUSY;
+        break;
+      }
+      allShared |= pX->sharedMask;
+    }
+
+    /* Get shared locks at the system level, if necessary */
+    if( rc==SQLITE_OK ){
+      if( (allShared & mask)==0 ){
+        rc = winShmSystemLock(pShmNode, WINSHM_RDLCK, ofst+WIN_SHM_BASE, n);
+      }else{
+        rc = SQLITE_OK;
+      }
+    }
+
+    /* Get the local shared locks */
+    if( rc==SQLITE_OK ){
+      p->sharedMask |= mask;
+    }
+  }else{
+    /* Make sure no sibling connections hold locks that will block this
+    ** lock.  If any do, return SQLITE_BUSY right away.
+    */
+    for(pX=pShmNode->pFirst; pX; pX=pX->pNext){
+      if( (pX->exclMask & mask)!=0 || (pX->sharedMask & mask)!=0 ){
+        rc = SQLITE_BUSY;
+        break;
+      }
+    }
+
+    /* Get the exclusive locks at the system level.  Then if successful
+    ** also mark the local connection as being locked.
+    */
+    if( rc==SQLITE_OK ){
+      rc = winShmSystemLock(pShmNode, WINSHM_WRLCK, ofst+WIN_SHM_BASE, n);
+      if( rc==SQLITE_OK ){
+        assert( (p->sharedMask & mask)==0 );
+        p->exclMask |= mask;
+      }
+    }
+  }
+  sqlite3_mutex_leave(pShmNode->mutex);
+  OSTRACE(("SHM-LOCK pid=%lu, id=%d, sharedMask=%03x, exclMask=%03x, rc=%s\n",
+           osGetCurrentProcessId(), p->id, p->sharedMask, p->exclMask,
+           sqlite3ErrName(rc)));
+  return rc;
+}
+
+/*
+** Implement a memory barrier or memory fence on shared memory.
+**
+** All loads and stores begun before the barrier must complete before
+** any load or store begun after the barrier.
+*/
+static void winShmBarrier(
+  sqlite3_file *fd          /* Database holding the shared memory */
+){
+  UNUSED_PARAMETER(fd);
+  sqlite3MemoryBarrier();   /* compiler-defined memory barrier */
+  winShmEnterMutex();       /* Also mutex, for redundancy */
+  winShmLeaveMutex();
+}
+
+/*
+** This function is called to obtain a pointer to region iRegion of the
+** shared-memory associated with the database file fd. Shared-memory regions
+** are numbered starting from zero. Each shared-memory region is szRegion
+** bytes in size.
+**
+** If an error occurs, an error code is returned and *pp is set to NULL.
+**
+** Otherwise, if the isWrite parameter is 0 and the requested shared-memory
+** region has not been allocated (by any client, including one running in a
+** separate process), then *pp is set to NULL and SQLITE_OK returned. If
+** isWrite is non-zero and the requested shared-memory region has not yet
+** been allocated, it is allocated by this function.
+**
+** If the shared-memory region has already been allocated or is allocated by
+** this call as described above, then it is mapped into this processes
+** address space (if it is not already), *pp is set to point to the mapped
+** memory and SQLITE_OK returned.
+*/
+static int winShmMap(
+  sqlite3_file *fd,               /* Handle open on database file */
+  int iRegion,                    /* Region to retrieve */
+  int szRegion,                   /* Size of regions */
+  int isWrite,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Mapped memory */
+){
+  winFile *pDbFd = (winFile*)fd;
+  winShm *pShm = pDbFd->pShm;
+  winShmNode *pShmNode;
+  DWORD protect = PAGE_READWRITE;
+  DWORD flags = FILE_MAP_WRITE | FILE_MAP_READ;
+  int rc = SQLITE_OK;
+
+  if( !pShm ){
+    rc = winOpenSharedMemory(pDbFd);
+    if( rc!=SQLITE_OK ) return rc;
+    pShm = pDbFd->pShm;
+    assert( pShm!=0 );
+  }
+  pShmNode = pShm->pShmNode;
+
+  sqlite3_mutex_enter(pShmNode->mutex);
+  if( pShmNode->isUnlocked ){
+    rc = winLockSharedMemory(pShmNode);
+    if( rc!=SQLITE_OK ) goto shmpage_out;
+    pShmNode->isUnlocked = 0;
+  }
+  assert( szRegion==pShmNode->szRegion || pShmNode->nRegion==0 );
+
+  if( pShmNode->nRegion<=iRegion ){
+    struct ShmRegion *apNew;           /* New aRegion[] array */
+    int nByte = (iRegion+1)*szRegion;  /* Minimum required file size */
+    sqlite3_int64 sz;                  /* Current size of wal-index file */
+
+    pShmNode->szRegion = szRegion;
+
+    /* The requested region is not mapped into this processes address space.
+    ** Check to see if it has been allocated (i.e. if the wal-index file is
+    ** large enough to contain the requested region).
+    */
+    rc = winFileSize((sqlite3_file *)&pShmNode->hFile, &sz);
+    if( rc!=SQLITE_OK ){
+      rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
+                       "winShmMap1", pDbFd->zPath);
+      goto shmpage_out;
+    }
+
+    if( sz<nByte ){
+      /* The requested memory region does not exist. If isWrite is set to
+      ** zero, exit early. *pp will be set to NULL and SQLITE_OK returned.
+      **
+      ** Alternatively, if isWrite is non-zero, use ftruncate() to allocate
+      ** the requested memory region.
+      */
+      if( !isWrite ) goto shmpage_out;
+      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, nByte);
+      if( rc!=SQLITE_OK ){
+        rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
+                         "winShmMap2", pDbFd->zPath);
+        goto shmpage_out;
+      }
+    }
+
+    /* Map the requested memory region into this processes address space. */
+    apNew = (struct ShmRegion *)sqlite3_realloc64(
+        pShmNode->aRegion, (iRegion+1)*sizeof(apNew[0])
+    );
+    if( !apNew ){
+      rc = SQLITE_IOERR_NOMEM_BKPT;
+      goto shmpage_out;
+    }
+    pShmNode->aRegion = apNew;
+
+    if( pShmNode->isReadonly ){
+      protect = PAGE_READONLY;
+      flags = FILE_MAP_READ;
+    }
+
+    while( pShmNode->nRegion<=iRegion ){
+      HANDLE hMap = NULL;         /* file-mapping handle */
+      void *pMap = 0;             /* Mapped memory region */
+
+#if SQLITE_OS_WINRT
+      hMap = osCreateFileMappingFromApp(pShmNode->hFile.h,
+          NULL, protect, nByte, NULL
+      );
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+      hMap = osCreateFileMappingW(pShmNode->hFile.h,
+          NULL, protect, 0, nByte, NULL
+      );
+#elif defined(SQLITE_WIN32_HAS_ANSI) && SQLITE_WIN32_CREATEFILEMAPPINGA
+      hMap = osCreateFileMappingA(pShmNode->hFile.h,
+          NULL, protect, 0, nByte, NULL
+      );
+#endif
+      OSTRACE(("SHM-MAP-CREATE pid=%lu, region=%d, size=%d, rc=%s\n",
+               osGetCurrentProcessId(), pShmNode->nRegion, nByte,
+               hMap ? "ok" : "failed"));
+      if( hMap ){
+        int iOffset = pShmNode->nRegion*szRegion;
+        int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
+#if SQLITE_OS_WINRT
+        pMap = osMapViewOfFileFromApp(hMap, flags,
+            iOffset - iOffsetShift, szRegion + iOffsetShift
+        );
+#else
+        pMap = osMapViewOfFile(hMap, flags,
+            0, iOffset - iOffsetShift, szRegion + iOffsetShift
+        );
+#endif
+        OSTRACE(("SHM-MAP-MAP pid=%lu, region=%d, offset=%d, size=%d, rc=%s\n",
+                 osGetCurrentProcessId(), pShmNode->nRegion, iOffset,
+                 szRegion, pMap ? "ok" : "failed"));
+      }
+      if( !pMap ){
+        pShmNode->lastErrno = osGetLastError();
+        rc = winLogError(SQLITE_IOERR_SHMMAP, pShmNode->lastErrno,
+                         "winShmMap3", pDbFd->zPath);
+        if( hMap ) osCloseHandle(hMap);
+        goto shmpage_out;
+      }
+
+      pShmNode->aRegion[pShmNode->nRegion].pMap = pMap;
+      pShmNode->aRegion[pShmNode->nRegion].hMap = hMap;
+      pShmNode->nRegion++;
+    }
+  }
+
+shmpage_out:
+  if( pShmNode->nRegion>iRegion ){
+    int iOffset = iRegion*szRegion;
+    int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
+    char *p = (char *)pShmNode->aRegion[iRegion].pMap;
+    *pp = (void *)&p[iOffsetShift];
+  }else{
+    *pp = 0;
+  }
+  if( pShmNode->isReadonly && rc==SQLITE_OK ) rc = SQLITE_READONLY;
+  sqlite3_mutex_leave(pShmNode->mutex);
+  return rc;
+}
+
+#else
+# define winShmMap     0
+# define winShmLock    0
+# define winShmBarrier 0
+# define winShmUnmap   0
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
+/*
+** Cleans up the mapped region of the specified file, if any.
+*/
+#if SQLITE_MAX_MMAP_SIZE>0
+static int winUnmapfile(winFile *pFile){
+  assert( pFile!=0 );
+  OSTRACE(("UNMAP-FILE pid=%lu, pFile=%p, hMap=%p, pMapRegion=%p, "
+           "mmapSize=%lld, mmapSizeMax=%lld\n",
+           osGetCurrentProcessId(), pFile, pFile->hMap, pFile->pMapRegion,
+           pFile->mmapSize, pFile->mmapSizeMax));
+  if( pFile->pMapRegion ){
+    if( !osUnmapViewOfFile(pFile->pMapRegion) ){
+      pFile->lastErrno = osGetLastError();
+      OSTRACE(("UNMAP-FILE pid=%lu, pFile=%p, pMapRegion=%p, "
+               "rc=SQLITE_IOERR_MMAP\n", osGetCurrentProcessId(), pFile,
+               pFile->pMapRegion));
+      return winLogError(SQLITE_IOERR_MMAP, pFile->lastErrno,
+                         "winUnmapfile1", pFile->zPath);
+    }
+    pFile->pMapRegion = 0;
+    pFile->mmapSize = 0;
+  }
+  if( pFile->hMap!=NULL ){
+    if( !osCloseHandle(pFile->hMap) ){
+      pFile->lastErrno = osGetLastError();
+      OSTRACE(("UNMAP-FILE pid=%lu, pFile=%p, hMap=%p, rc=SQLITE_IOERR_MMAP\n",
+               osGetCurrentProcessId(), pFile, pFile->hMap));
+      return winLogError(SQLITE_IOERR_MMAP, pFile->lastErrno,
+                         "winUnmapfile2", pFile->zPath);
+    }
+    pFile->hMap = NULL;
+  }
+  OSTRACE(("UNMAP-FILE pid=%lu, pFile=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFile));
+  return SQLITE_OK;
+}
+
+/*
+** Memory map or remap the file opened by file-descriptor pFd (if the file
+** is already mapped, the existing mapping is replaced by the new). Or, if
+** there already exists a mapping for this file, and there are still
+** outstanding xFetch() references to it, this function is a no-op.
+**
+** If parameter nByte is non-negative, then it is the requested size of
+** the mapping to create. Otherwise, if nByte is less than zero, then the
+** requested size is the size of the file on disk. The actual size of the
+** created mapping is either the requested size or the value configured
+** using SQLITE_FCNTL_MMAP_SIZE, whichever is smaller.
+**
+** SQLITE_OK is returned if no error occurs (even if the mapping is not
+** recreated as a result of outstanding references) or an SQLite error
+** code otherwise.
+*/
+static int winMapfile(winFile *pFd, sqlite3_int64 nByte){
+  sqlite3_int64 nMap = nByte;
+  int rc;
+
+  assert( nMap>=0 || pFd->nFetchOut==0 );
+  OSTRACE(("MAP-FILE pid=%lu, pFile=%p, size=%lld\n",
+           osGetCurrentProcessId(), pFd, nByte));
+
+  if( pFd->nFetchOut>0 ) return SQLITE_OK;
+
+  if( nMap<0 ){
+    rc = winFileSize((sqlite3_file*)pFd, &nMap);
+    if( rc ){
+      OSTRACE(("MAP-FILE pid=%lu, pFile=%p, rc=SQLITE_IOERR_FSTAT\n",
+               osGetCurrentProcessId(), pFd));
+      return SQLITE_IOERR_FSTAT;
+    }
+  }
+  if( nMap>pFd->mmapSizeMax ){
+    nMap = pFd->mmapSizeMax;
+  }
+  nMap &= ~(sqlite3_int64)(winSysInfo.dwPageSize - 1);
+
+  if( nMap==0 && pFd->mmapSize>0 ){
+    winUnmapfile(pFd);
+  }
+  if( nMap!=pFd->mmapSize ){
+    void *pNew = 0;
+    DWORD protect = PAGE_READONLY;
+    DWORD flags = FILE_MAP_READ;
+
+    winUnmapfile(pFd);
+#ifdef SQLITE_MMAP_READWRITE
+    if( (pFd->ctrlFlags & WINFILE_RDONLY)==0 ){
+      protect = PAGE_READWRITE;
+      flags |= FILE_MAP_WRITE;
+    }
+#endif
+#if SQLITE_OS_WINRT
+    pFd->hMap = osCreateFileMappingFromApp(pFd->h, NULL, protect, nMap, NULL);
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+    pFd->hMap = osCreateFileMappingW(pFd->h, NULL, protect,
+                                (DWORD)((nMap>>32) & 0xffffffff),
+                                (DWORD)(nMap & 0xffffffff), NULL);
+#elif defined(SQLITE_WIN32_HAS_ANSI) && SQLITE_WIN32_CREATEFILEMAPPINGA
+    pFd->hMap = osCreateFileMappingA(pFd->h, NULL, protect,
+                                (DWORD)((nMap>>32) & 0xffffffff),
+                                (DWORD)(nMap & 0xffffffff), NULL);
+#endif
+    if( pFd->hMap==NULL ){
+      pFd->lastErrno = osGetLastError();
+      rc = winLogError(SQLITE_IOERR_MMAP, pFd->lastErrno,
+                       "winMapfile1", pFd->zPath);
+      /* Log the error, but continue normal operation using xRead/xWrite */
+      OSTRACE(("MAP-FILE-CREATE pid=%lu, pFile=%p, rc=%s\n",
+               osGetCurrentProcessId(), pFd, sqlite3ErrName(rc)));
+      return SQLITE_OK;
+    }
+    assert( (nMap % winSysInfo.dwPageSize)==0 );
+    assert( sizeof(SIZE_T)==sizeof(sqlite3_int64) || nMap<=0xffffffff );
+#if SQLITE_OS_WINRT
+    pNew = osMapViewOfFileFromApp(pFd->hMap, flags, 0, (SIZE_T)nMap);
+#else
+    pNew = osMapViewOfFile(pFd->hMap, flags, 0, 0, (SIZE_T)nMap);
+#endif
+    if( pNew==NULL ){
+      osCloseHandle(pFd->hMap);
+      pFd->hMap = NULL;
+      pFd->lastErrno = osGetLastError();
+      rc = winLogError(SQLITE_IOERR_MMAP, pFd->lastErrno,
+                       "winMapfile2", pFd->zPath);
+      /* Log the error, but continue normal operation using xRead/xWrite */
+      OSTRACE(("MAP-FILE-MAP pid=%lu, pFile=%p, rc=%s\n",
+               osGetCurrentProcessId(), pFd, sqlite3ErrName(rc)));
+      return SQLITE_OK;
+    }
+    pFd->pMapRegion = pNew;
+    pFd->mmapSize = nMap;
+  }
+
+  OSTRACE(("MAP-FILE pid=%lu, pFile=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), pFd));
+  return SQLITE_OK;
+}
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+
+/*
+** If possible, return a pointer to a mapping of file fd starting at offset
+** iOff. The mapping must be valid for at least nAmt bytes.
+**
+** If such a pointer can be obtained, store it in *pp and return SQLITE_OK.
+** Or, if one cannot but no error occurs, set *pp to 0 and return SQLITE_OK.
+** Finally, if an error does occur, return an SQLite error code. The final
+** value of *pp is undefined in this case.
+**
+** If this function does return a pointer, the caller must eventually
+** release the reference by calling winUnfetch().
+*/
+static int winFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){
+#if SQLITE_MAX_MMAP_SIZE>0
+  winFile *pFd = (winFile*)fd;   /* The underlying database file */
+#endif
+  *pp = 0;
+
+  OSTRACE(("FETCH pid=%lu, pFile=%p, offset=%lld, amount=%d, pp=%p\n",
+           osGetCurrentProcessId(), fd, iOff, nAmt, pp));
+
+#if SQLITE_MAX_MMAP_SIZE>0
+  if( pFd->mmapSizeMax>0 ){
+    /* Ensure that there is always at least a 256 byte buffer of addressable
+    ** memory following the returned page. If the database is corrupt,
+    ** SQLite may overread the page slightly (in practice only a few bytes,
+    ** but 256 is safe, round, number).  */
+    const int nEofBuffer = 256;
+    if( pFd->pMapRegion==0 ){
+      int rc = winMapfile(pFd, -1);
+      if( rc!=SQLITE_OK ){
+        OSTRACE(("FETCH pid=%lu, pFile=%p, rc=%s\n",
+                 osGetCurrentProcessId(), pFd, sqlite3ErrName(rc)));
+        return rc;
+      }
+    }
+    if( pFd->mmapSize >= (iOff+nAmt+nEofBuffer) ){
+      assert( pFd->pMapRegion!=0 );
+      *pp = &((u8 *)pFd->pMapRegion)[iOff];
+      pFd->nFetchOut++;
+    }
+  }
+#endif
+
+  OSTRACE(("FETCH pid=%lu, pFile=%p, pp=%p, *pp=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), fd, pp, *pp));
+  return SQLITE_OK;
+}
+
+/*
+** If the third argument is non-NULL, then this function releases a
+** reference obtained by an earlier call to winFetch(). The second
+** argument passed to this function must be the same as the corresponding
+** argument that was passed to the winFetch() invocation.
+**
+** Or, if the third argument is NULL, then this function is being called
+** to inform the VFS layer that, according to POSIX, any existing mapping
+** may now be invalid and should be unmapped.
+*/
+static int winUnfetch(sqlite3_file *fd, i64 iOff, void *p){
+#if SQLITE_MAX_MMAP_SIZE>0
+  winFile *pFd = (winFile*)fd;   /* The underlying database file */
+
+  /* If p==0 (unmap the entire file) then there must be no outstanding
+  ** xFetch references. Or, if p!=0 (meaning it is an xFetch reference),
+  ** then there must be at least one outstanding.  */
+  assert( (p==0)==(pFd->nFetchOut==0) );
+
+  /* If p!=0, it must match the iOff value. */
+  assert( p==0 || p==&((u8 *)pFd->pMapRegion)[iOff] );
+
+  OSTRACE(("UNFETCH pid=%lu, pFile=%p, offset=%lld, p=%p\n",
+           osGetCurrentProcessId(), pFd, iOff, p));
+
+  if( p ){
+    pFd->nFetchOut--;
+  }else{
+    /* FIXME:  If Windows truly always prevents truncating or deleting a
+    ** file while a mapping is held, then the following winUnmapfile() call
+    ** is unnecessary can be omitted - potentially improving
+    ** performance.  */
+    winUnmapfile(pFd);
+  }
+
+  assert( pFd->nFetchOut>=0 );
+#endif
+
+  OSTRACE(("UNFETCH pid=%lu, pFile=%p, rc=SQLITE_OK\n",
+           osGetCurrentProcessId(), fd));
+  return SQLITE_OK;
+}
+
+/*
+** Here ends the implementation of all sqlite3_file methods.
+**
+********************** End sqlite3_file Methods *******************************
+******************************************************************************/
+
+/*
+** This vector defines all the methods that can operate on an
+** sqlite3_file for win32.
+*/
+static const sqlite3_io_methods winIoMethod = {
+  3,                              /* iVersion */
+  winClose,                       /* xClose */
+  winRead,                        /* xRead */
+  winWrite,                       /* xWrite */
+  winTruncate,                    /* xTruncate */
+  winSync,                        /* xSync */
+  winFileSize,                    /* xFileSize */
+  winLock,                        /* xLock */
+  winUnlock,                      /* xUnlock */
+  winCheckReservedLock,           /* xCheckReservedLock */
+  winFileControl,                 /* xFileControl */
+  winSectorSize,                  /* xSectorSize */
+  winDeviceCharacteristics,       /* xDeviceCharacteristics */
+  winShmMap,                      /* xShmMap */
+  winShmLock,                     /* xShmLock */
+  winShmBarrier,                  /* xShmBarrier */
+  winShmUnmap,                    /* xShmUnmap */
+  winFetch,                       /* xFetch */
+  winUnfetch                      /* xUnfetch */
+};
+
+/*
+** This vector defines all the methods that can operate on an
+** sqlite3_file for win32 without performing any locking.
+*/
+static const sqlite3_io_methods winIoNolockMethod = {
+  3,                              /* iVersion */
+  winClose,                       /* xClose */
+  winRead,                        /* xRead */
+  winWrite,                       /* xWrite */
+  winTruncate,                    /* xTruncate */
+  winSync,                        /* xSync */
+  winFileSize,                    /* xFileSize */
+  winNolockLock,                  /* xLock */
+  winNolockUnlock,                /* xUnlock */
+  winNolockCheckReservedLock,     /* xCheckReservedLock */
+  winFileControl,                 /* xFileControl */
+  winSectorSize,                  /* xSectorSize */
+  winDeviceCharacteristics,       /* xDeviceCharacteristics */
+  winShmMap,                      /* xShmMap */
+  winShmLock,                     /* xShmLock */
+  winShmBarrier,                  /* xShmBarrier */
+  winShmUnmap,                    /* xShmUnmap */
+  winFetch,                       /* xFetch */
+  winUnfetch                      /* xUnfetch */
+};
+
+static winVfsAppData winAppData = {
+  &winIoMethod,       /* pMethod */
+  0,                  /* pAppData */
+  0                   /* bNoLock */
+};
+
+static winVfsAppData winNolockAppData = {
+  &winIoNolockMethod, /* pMethod */
+  0,                  /* pAppData */
+  1                   /* bNoLock */
+};
+
+/****************************************************************************
+**************************** sqlite3_vfs methods ****************************
+**
+** This division contains the implementation of methods on the
+** sqlite3_vfs object.
+*/
+
+#if defined(__CYGWIN__)
+/*
+** Convert a filename from whatever the underlying operating system
+** supports for filenames into UTF-8.  Space to hold the result is
+** obtained from malloc and must be freed by the calling function.
+*/
+static char *winConvertToUtf8Filename(const void *zFilename){
+  char *zConverted = 0;
+  if( osIsNT() ){
+    zConverted = winUnicodeToUtf8(zFilename);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    zConverted = winMbcsToUtf8(zFilename, osAreFileApisANSI());
+  }
+#endif
+  /* caller will handle out of memory */
+  return zConverted;
+}
+#endif
+
+/*
+** Convert a UTF-8 filename into whatever form the underlying
+** operating system wants filenames in.  Space to hold the result
+** is obtained from malloc and must be freed by the calling
+** function.
+*/
+static void *winConvertFromUtf8Filename(const char *zFilename){
+  void *zConverted = 0;
+  if( osIsNT() ){
+    zConverted = winUtf8ToUnicode(zFilename);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    zConverted = winUtf8ToMbcs(zFilename, osAreFileApisANSI());
+  }
+#endif
+  /* caller will handle out of memory */
+  return zConverted;
+}
+
+/*
+** This function returns non-zero if the specified UTF-8 string buffer
+** ends with a directory separator character or one was successfully
+** added to it.
+*/
+static int winMakeEndInDirSep(int nBuf, char *zBuf){
+  if( zBuf ){
+    int nLen = sqlite3Strlen30(zBuf);
+    if( nLen>0 ){
+      if( winIsDirSep(zBuf[nLen-1]) ){
+        return 1;
+      }else if( nLen+1<nBuf ){
+        zBuf[nLen] = winGetDirSep();
+        zBuf[nLen+1] = '\0';
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** If sqlite3_temp_directory is defined, take the mutex and return true.
+**
+** If sqlite3_temp_directory is NULL (undefined), omit the mutex and
+** return false.
+*/
+static int winTempDirDefined(void){
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  if( sqlite3_temp_directory!=0 ) return 1;
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  return 0;
+}
+
+/*
+** Create a temporary file name and store the resulting pointer into pzBuf.
+** The pointer returned in pzBuf must be freed via sqlite3_free().
+*/
+static int winGetTempname(sqlite3_vfs *pVfs, char **pzBuf){
+  static char zChars[] =
+    "abcdefghijklmnopqrstuvwxyz"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "0123456789";
+  size_t i, j;
+  DWORD pid;
+  int nPre = sqlite3Strlen30(SQLITE_TEMP_FILE_PREFIX);
+  int nMax, nBuf, nDir, nLen;
+  char *zBuf;
+
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing.
+  */
+  SimulateIOError( return SQLITE_IOERR );
+
+  /* Allocate a temporary buffer to store the fully qualified file
+  ** name for the temporary file.  If this fails, we cannot continue.
+  */
+  nMax = pVfs->mxPathname; nBuf = nMax + 2;
+  zBuf = sqlite3MallocZero( nBuf );
+  if( !zBuf ){
+    OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+
+  /* Figure out the effective temporary directory.  First, check if one
+  ** has been explicitly set by the application; otherwise, use the one
+  ** configured by the operating system.
+  */
+  nDir = nMax - (nPre + 15);
+  assert( nDir>0 );
+  if( winTempDirDefined() ){
+    int nDirLen = sqlite3Strlen30(sqlite3_temp_directory);
+    if( nDirLen>0 ){
+      if( !winIsDirSep(sqlite3_temp_directory[nDirLen-1]) ){
+        nDirLen++;
+      }
+      if( nDirLen>nDir ){
+        sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+        sqlite3_free(zBuf);
+        OSTRACE(("TEMP-FILENAME rc=SQLITE_ERROR\n"));
+        return winLogError(SQLITE_ERROR, 0, "winGetTempname1", 0);
+      }
+      sqlite3_snprintf(nMax, zBuf, "%s", sqlite3_temp_directory);
+    }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+  }
+
+#if defined(__CYGWIN__)
+  else{
+    static const char *azDirs[] = {
+       0, /* getenv("SQLITE_TMPDIR") */
+       0, /* getenv("TMPDIR") */
+       0, /* getenv("TMP") */
+       0, /* getenv("TEMP") */
+       0, /* getenv("USERPROFILE") */
+       "/var/tmp",
+       "/usr/tmp",
+       "/tmp",
+       ".",
+       0        /* List terminator */
+    };
+    unsigned int i;
+    const char *zDir = 0;
+
+    if( !azDirs[0] ) azDirs[0] = getenv("SQLITE_TMPDIR");
+    if( !azDirs[1] ) azDirs[1] = getenv("TMPDIR");
+    if( !azDirs[2] ) azDirs[2] = getenv("TMP");
+    if( !azDirs[3] ) azDirs[3] = getenv("TEMP");
+    if( !azDirs[4] ) azDirs[4] = getenv("USERPROFILE");
+    for(i=0; i<sizeof(azDirs)/sizeof(azDirs[0]); zDir=azDirs[i++]){
+      void *zConverted;
+      if( zDir==0 ) continue;
+      /* If the path starts with a drive letter followed by the colon
+      ** character, assume it is already a native Win32 path; otherwise,
+      ** it must be converted to a native Win32 path via the Cygwin API
+      ** prior to using it.
+      */
+      if( winIsDriveLetterAndColon(zDir) ){
+        zConverted = winConvertFromUtf8Filename(zDir);
+        if( !zConverted ){
+          sqlite3_free(zBuf);
+          OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+          return SQLITE_IOERR_NOMEM_BKPT;
+        }
+        if( winIsDir(zConverted) ){
+          sqlite3_snprintf(nMax, zBuf, "%s", zDir);
+          sqlite3_free(zConverted);
+          break;
+        }
+        sqlite3_free(zConverted);
+      }else{
+        zConverted = sqlite3MallocZero( nMax+1 );
+        if( !zConverted ){
+          sqlite3_free(zBuf);
+          OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+          return SQLITE_IOERR_NOMEM_BKPT;
+        }
+        if( cygwin_conv_path(
+                osIsNT() ? CCP_POSIX_TO_WIN_W : CCP_POSIX_TO_WIN_A, zDir,
+                zConverted, nMax+1)<0 ){
+          sqlite3_free(zConverted);
+          sqlite3_free(zBuf);
+          OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_CONVPATH\n"));
+          return winLogError(SQLITE_IOERR_CONVPATH, (DWORD)errno,
+                             "winGetTempname2", zDir);
+        }
+        if( winIsDir(zConverted) ){
+          /* At this point, we know the candidate directory exists and should
+          ** be used.  However, we may need to convert the string containing
+          ** its name into UTF-8 (i.e. if it is UTF-16 right now).
+          */
+          char *zUtf8 = winConvertToUtf8Filename(zConverted);
+          if( !zUtf8 ){
+            sqlite3_free(zConverted);
+            sqlite3_free(zBuf);
+            OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+            return SQLITE_IOERR_NOMEM_BKPT;
+          }
+          sqlite3_snprintf(nMax, zBuf, "%s", zUtf8);
+          sqlite3_free(zUtf8);
+          sqlite3_free(zConverted);
+          break;
+        }
+        sqlite3_free(zConverted);
+      }
+    }
+  }
+#elif !SQLITE_OS_WINRT && !defined(__CYGWIN__)
+  else if( osIsNT() ){
+    char *zMulti;
+    LPWSTR zWidePath = sqlite3MallocZero( nMax*sizeof(WCHAR) );
+    if( !zWidePath ){
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    if( osGetTempPathW(nMax, zWidePath)==0 ){
+      sqlite3_free(zWidePath);
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_GETTEMPPATH\n"));
+      return winLogError(SQLITE_IOERR_GETTEMPPATH, osGetLastError(),
+                         "winGetTempname2", 0);
+    }
+    zMulti = winUnicodeToUtf8(zWidePath);
+    if( zMulti ){
+      sqlite3_snprintf(nMax, zBuf, "%s", zMulti);
+      sqlite3_free(zMulti);
+      sqlite3_free(zWidePath);
+    }else{
+      sqlite3_free(zWidePath);
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    char *zUtf8;
+    char *zMbcsPath = sqlite3MallocZero( nMax );
+    if( !zMbcsPath ){
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    if( osGetTempPathA(nMax, zMbcsPath)==0 ){
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_GETTEMPPATH\n"));
+      return winLogError(SQLITE_IOERR_GETTEMPPATH, osGetLastError(),
+                         "winGetTempname3", 0);
+    }
+    zUtf8 = winMbcsToUtf8(zMbcsPath, osAreFileApisANSI());
+    if( zUtf8 ){
+      sqlite3_snprintf(nMax, zBuf, "%s", zUtf8);
+      sqlite3_free(zUtf8);
+    }else{
+      sqlite3_free(zBuf);
+      OSTRACE(("TEMP-FILENAME rc=SQLITE_IOERR_NOMEM\n"));
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+  }
+#endif /* SQLITE_WIN32_HAS_ANSI */
+#endif /* !SQLITE_OS_WINRT */
+
+  /*
+  ** Check to make sure the temporary directory ends with an appropriate
+  ** separator.  If it does not and there is not enough space left to add
+  ** one, fail.
+  */
+  if( !winMakeEndInDirSep(nDir+1, zBuf) ){
+    sqlite3_free(zBuf);
+    OSTRACE(("TEMP-FILENAME rc=SQLITE_ERROR\n"));
+    return winLogError(SQLITE_ERROR, 0, "winGetTempname4", 0);
+  }
+
+  /*
+  ** Check that the output buffer is large enough for the temporary file
+  ** name in the following format:
+  **
+  **   "<temporary_directory>/etilqs_XXXXXXXXXXXXXXX\0\0"
+  **
+  ** If not, return SQLITE_ERROR.  The number 17 is used here in order to
+  ** account for the space used by the 15 character random suffix and the
+  ** two trailing NUL characters.  The final directory separator character
+  ** has already added if it was not already present.
+  */
+  nLen = sqlite3Strlen30(zBuf);
+  if( (nLen + nPre + 17) > nBuf ){
+    sqlite3_free(zBuf);
+    OSTRACE(("TEMP-FILENAME rc=SQLITE_ERROR\n"));
+    return winLogError(SQLITE_ERROR, 0, "winGetTempname5", 0);
+  }
+
+  sqlite3_snprintf(nBuf-16-nLen, zBuf+nLen, SQLITE_TEMP_FILE_PREFIX);
+
+  j = sqlite3Strlen30(zBuf);
+  sqlite3_randomness(15, &zBuf[j]);
+  pid = osGetCurrentProcessId();
+  for(i=0; i<15; i++, j++){
+    zBuf[j] += pid & 0xff;
+    pid >>= 8;
+    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
+  }
+  zBuf[j] = 0;
+  zBuf[j+1] = 0;
+  *pzBuf = zBuf;
+
+  OSTRACE(("TEMP-FILENAME name=%s, rc=SQLITE_OK\n", zBuf));
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the named file is really a directory.  Return false if
+** it is something other than a directory, or if there is any kind of memory
+** allocation failure.
+*/
+static int winIsDir(const void *zConverted){
+  DWORD attr;
+  int rc = 0;
+  DWORD lastErrno;
+
+  if( osIsNT() ){
+    int cnt = 0;
+    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+    memset(&sAttrData, 0, sizeof(sAttrData));
+    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
+                             GetFileExInfoStandard,
+                             &sAttrData)) && winRetryIoerr(&cnt, &lastErrno) ){}
+    if( !rc ){
+      return 0; /* Invalid name? */
+    }
+    attr = sAttrData.dwFileAttributes;
+#if SQLITE_OS_WINCE==0
+  }else{
+    attr = osGetFileAttributesA((char*)zConverted);
+#endif
+  }
+  return (attr!=INVALID_FILE_ATTRIBUTES) && (attr&FILE_ATTRIBUTE_DIRECTORY);
+}
+
+/* forward reference */
+static int winAccess(
+  sqlite3_vfs *pVfs,         /* Not used on win32 */
+  const char *zFilename,     /* Name of file to check */
+  int flags,                 /* Type of test to make on this file */
+  int *pResOut               /* OUT: Result */
+);
+
+/*
+** Open a file.
+*/
+static int winOpen(
+  sqlite3_vfs *pVfs,        /* Used to get maximum path length and AppData */
+  const char *zName,        /* Name of the file (UTF-8) */
+  sqlite3_file *id,         /* Write the SQLite file handle here */
+  int flags,                /* Open mode flags */
+  int *pOutFlags            /* Status return flags */
+){
+  HANDLE h;
+  DWORD lastErrno = 0;
+  DWORD dwDesiredAccess;
+  DWORD dwShareMode;
+  DWORD dwCreationDisposition;
+  DWORD dwFlagsAndAttributes = 0;
+#if SQLITE_OS_WINCE
+  int isTemp = 0;
+#endif
+  winVfsAppData *pAppData;
+  winFile *pFile = (winFile*)id;
+  void *zConverted;              /* Filename in OS encoding */
+  const char *zUtf8Name = zName; /* Filename in UTF-8 encoding */
+  int cnt = 0;
+
+  /* If argument zPath is a NULL pointer, this function is required to open
+  ** a temporary file. Use this buffer to store the file name in.
+  */
+  char *zTmpname = 0; /* For temporary filename, if necessary. */
+
+  int rc = SQLITE_OK;            /* Function Return Code */
+#if !defined(NDEBUG) || SQLITE_OS_WINCE
+  int eType = flags&0x0FFF00;  /* Type of file to open */
+#endif
+
+  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
+  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
+  int isCreate     = (flags & SQLITE_OPEN_CREATE);
+  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
+  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
+
+#ifndef NDEBUG
+  int isOpenJournal = (isCreate && (
+        eType==SQLITE_OPEN_SUPER_JOURNAL
+     || eType==SQLITE_OPEN_MAIN_JOURNAL
+     || eType==SQLITE_OPEN_WAL
+  ));
+#endif
+
+  OSTRACE(("OPEN name=%s, pFile=%p, flags=%x, pOutFlags=%p\n",
+           zUtf8Name, id, flags, pOutFlags));
+
+  /* Check the following statements are true:
+  **
+  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and
+  **   (b) if CREATE is set, then READWRITE must also be set, and
+  **   (c) if EXCLUSIVE is set, then CREATE must also be set.
+  **   (d) if DELETEONCLOSE is set, then CREATE must also be set.
+  */
+  assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly));
+  assert(isCreate==0 || isReadWrite);
+  assert(isExclusive==0 || isCreate);
+  assert(isDelete==0 || isCreate);
+
+  /* The main DB, main journal, WAL file and super-journal are never
+  ** automatically deleted. Nor are they ever temporary files.  */
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_DB );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_MAIN_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_SUPER_JOURNAL );
+  assert( (!isDelete && zName) || eType!=SQLITE_OPEN_WAL );
+
+  /* Assert that the upper layer has set one of the "file-type" flags. */
+  assert( eType==SQLITE_OPEN_MAIN_DB      || eType==SQLITE_OPEN_TEMP_DB
+       || eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL
+       || eType==SQLITE_OPEN_SUBJOURNAL   || eType==SQLITE_OPEN_SUPER_JOURNAL
+       || eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL
+  );
+
+  assert( pFile!=0 );
+  memset(pFile, 0, sizeof(winFile));
+  pFile->h = INVALID_HANDLE_VALUE;
+
+#if SQLITE_OS_WINRT
+  if( !zUtf8Name && !sqlite3_temp_directory ){
+    sqlite3_log(SQLITE_ERROR,
+        "sqlite3_temp_directory variable should be set for WinRT");
+  }
+#endif
+
+  /* If the second argument to this function is NULL, generate a
+  ** temporary file name to use
+  */
+  if( !zUtf8Name ){
+    assert( isDelete && !isOpenJournal );
+    rc = winGetTempname(pVfs, &zTmpname);
+    if( rc!=SQLITE_OK ){
+      OSTRACE(("OPEN name=%s, rc=%s", zUtf8Name, sqlite3ErrName(rc)));
+      return rc;
+    }
+    zUtf8Name = zTmpname;
+  }
+
+  /* Database filenames are double-zero terminated if they are not
+  ** URIs with parameters.  Hence, they can always be passed into
+  ** sqlite3_uri_parameter().
+  */
+  assert( (eType!=SQLITE_OPEN_MAIN_DB) || (flags & SQLITE_OPEN_URI) ||
+       zUtf8Name[sqlite3Strlen30(zUtf8Name)+1]==0 );
+
+  /* Convert the filename to the system encoding. */
+  zConverted = winConvertFromUtf8Filename(zUtf8Name);
+  if( zConverted==0 ){
+    sqlite3_free(zTmpname);
+    OSTRACE(("OPEN name=%s, rc=SQLITE_IOERR_NOMEM", zUtf8Name));
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+
+  if( winIsDir(zConverted) ){
+    sqlite3_free(zConverted);
+    sqlite3_free(zTmpname);
+    OSTRACE(("OPEN name=%s, rc=SQLITE_CANTOPEN_ISDIR", zUtf8Name));
+    return SQLITE_CANTOPEN_ISDIR;
+  }
+
+  if( isReadWrite ){
+    dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
+  }else{
+    dwDesiredAccess = GENERIC_READ;
+  }
+
+  /* SQLITE_OPEN_EXCLUSIVE is used to make sure that a new file is
+  ** created. SQLite doesn't use it to indicate "exclusive access"
+  ** as it is usually understood.
+  */
+  if( isExclusive ){
+    /* Creates a new file, only if it does not already exist. */
+    /* If the file exists, it fails. */
+    dwCreationDisposition = CREATE_NEW;
+  }else if( isCreate ){
+    /* Open existing file, or create if it doesn't exist */
+    dwCreationDisposition = OPEN_ALWAYS;
+  }else{
+    /* Opens a file, only if it exists. */
+    dwCreationDisposition = OPEN_EXISTING;
+  }
+
+  if( 0==sqlite3_uri_boolean(zName, "exclusive", 0) ){
+    dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;
+  }else{
+    dwShareMode = 0;
+  }
+
+  if( isDelete ){
+#if SQLITE_OS_WINCE
+    dwFlagsAndAttributes = FILE_ATTRIBUTE_HIDDEN;
+    isTemp = 1;
+#else
+    dwFlagsAndAttributes = FILE_ATTRIBUTE_TEMPORARY
+                               | FILE_ATTRIBUTE_HIDDEN
+                               | FILE_FLAG_DELETE_ON_CLOSE;
+#endif
+  }else{
+    dwFlagsAndAttributes = FILE_ATTRIBUTE_NORMAL;
+  }
+  /* Reports from the internet are that performance is always
+  ** better if FILE_FLAG_RANDOM_ACCESS is used.  Ticket #2699. */
+#if SQLITE_OS_WINCE
+  dwFlagsAndAttributes |= FILE_FLAG_RANDOM_ACCESS;
+#endif
+
+  if( osIsNT() ){
+#if SQLITE_OS_WINRT
+    CREATEFILE2_EXTENDED_PARAMETERS extendedParameters;
+    extendedParameters.dwSize = sizeof(CREATEFILE2_EXTENDED_PARAMETERS);
+    extendedParameters.dwFileAttributes =
+            dwFlagsAndAttributes & FILE_ATTRIBUTE_MASK;
+    extendedParameters.dwFileFlags = dwFlagsAndAttributes & FILE_FLAG_MASK;
+    extendedParameters.dwSecurityQosFlags = SECURITY_ANONYMOUS;
+    extendedParameters.lpSecurityAttributes = NULL;
+    extendedParameters.hTemplateFile = NULL;
+    do{
+      h = osCreateFile2((LPCWSTR)zConverted,
+                        dwDesiredAccess,
+                        dwShareMode,
+                        dwCreationDisposition,
+                        &extendedParameters);
+      if( h!=INVALID_HANDLE_VALUE ) break;
+      if( isReadWrite ){
+        int rc2, isRO = 0;
+        sqlite3BeginBenignMalloc();
+        rc2 = winAccess(pVfs, zUtf8Name, SQLITE_ACCESS_READ, &isRO);
+        sqlite3EndBenignMalloc();
+        if( rc2==SQLITE_OK && isRO ) break;
+      }
+    }while( winRetryIoerr(&cnt, &lastErrno) );
+#else
+    do{
+      h = osCreateFileW((LPCWSTR)zConverted,
+                        dwDesiredAccess,
+                        dwShareMode, NULL,
+                        dwCreationDisposition,
+                        dwFlagsAndAttributes,
+                        NULL);
+      if( h!=INVALID_HANDLE_VALUE ) break;
+      if( isReadWrite ){
+        int rc2, isRO = 0;
+        sqlite3BeginBenignMalloc();
+        rc2 = winAccess(pVfs, zUtf8Name, SQLITE_ACCESS_READ, &isRO);
+        sqlite3EndBenignMalloc();
+        if( rc2==SQLITE_OK && isRO ) break;
+      }
+    }while( winRetryIoerr(&cnt, &lastErrno) );
+#endif
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    do{
+      h = osCreateFileA((LPCSTR)zConverted,
+                        dwDesiredAccess,
+                        dwShareMode, NULL,
+                        dwCreationDisposition,
+                        dwFlagsAndAttributes,
+                        NULL);
+      if( h!=INVALID_HANDLE_VALUE ) break;
+      if( isReadWrite ){
+        int rc2, isRO = 0;
+        sqlite3BeginBenignMalloc();
+        rc2 = winAccess(pVfs, zUtf8Name, SQLITE_ACCESS_READ, &isRO);
+        sqlite3EndBenignMalloc();
+        if( rc2==SQLITE_OK && isRO ) break;
+      }
+    }while( winRetryIoerr(&cnt, &lastErrno) );
+  }
+#endif
+  winLogIoerr(cnt, __LINE__);
+
+  OSTRACE(("OPEN file=%p, name=%s, access=%lx, rc=%s\n", h, zUtf8Name,
+           dwDesiredAccess, (h==INVALID_HANDLE_VALUE) ? "failed" : "ok"));
+
+  if( h==INVALID_HANDLE_VALUE ){
+    sqlite3_free(zConverted);
+    sqlite3_free(zTmpname);
+    if( isReadWrite && !isExclusive ){
+      return winOpen(pVfs, zName, id,
+         ((flags|SQLITE_OPEN_READONLY) &
+                     ~(SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE)),
+         pOutFlags);
+    }else{
+      pFile->lastErrno = lastErrno;
+      winLogError(SQLITE_CANTOPEN, pFile->lastErrno, "winOpen", zUtf8Name);
+      return SQLITE_CANTOPEN_BKPT;
+    }
+  }
+
+  if( pOutFlags ){
+    if( isReadWrite ){
+      *pOutFlags = SQLITE_OPEN_READWRITE;
+    }else{
+      *pOutFlags = SQLITE_OPEN_READONLY;
+    }
+  }
+
+  OSTRACE(("OPEN file=%p, name=%s, access=%lx, pOutFlags=%p, *pOutFlags=%d, "
+           "rc=%s\n", h, zUtf8Name, dwDesiredAccess, pOutFlags, pOutFlags ?
+           *pOutFlags : 0, (h==INVALID_HANDLE_VALUE) ? "failed" : "ok"));
+
+  pAppData = (winVfsAppData*)pVfs->pAppData;
+
+#if SQLITE_OS_WINCE
+  {
+    if( isReadWrite && eType==SQLITE_OPEN_MAIN_DB
+         && ((pAppData==NULL) || !pAppData->bNoLock)
+         && (rc = winceCreateLock(zName, pFile))!=SQLITE_OK
+    ){
+      osCloseHandle(h);
+      sqlite3_free(zConverted);
+      sqlite3_free(zTmpname);
+      OSTRACE(("OPEN-CE-LOCK name=%s, rc=%s\n", zName, sqlite3ErrName(rc)));
+      return rc;
+    }
+  }
+  if( isTemp ){
+    pFile->zDeleteOnClose = zConverted;
+  }else
+#endif
+  {
+    sqlite3_free(zConverted);
+  }
+
+  sqlite3_free(zTmpname);
+  id->pMethods = pAppData ? pAppData->pMethod : &winIoMethod;
+  pFile->pVfs = pVfs;
+  pFile->h = h;
+  if( isReadonly ){
+    pFile->ctrlFlags |= WINFILE_RDONLY;
+  }
+  if( (flags & SQLITE_OPEN_MAIN_DB)
+   && sqlite3_uri_boolean(zName, "psow", SQLITE_POWERSAFE_OVERWRITE)
+  ){
+    pFile->ctrlFlags |= WINFILE_PSOW;
+  }
+  pFile->lastErrno = NO_ERROR;
+  pFile->zPath = zName;
+#if SQLITE_MAX_MMAP_SIZE>0
+  pFile->hMap = NULL;
+  pFile->pMapRegion = 0;
+  pFile->mmapSize = 0;
+  pFile->mmapSizeMax = sqlite3GlobalConfig.szMmap;
+#endif
+
+  OpenCounter(+1);
+  return rc;
+}
+
+/*
+** Delete the named file.
+**
+** Note that Windows does not allow a file to be deleted if some other
+** process has it open.  Sometimes a virus scanner or indexing program
+** will open a journal file shortly after it is created in order to do
+** whatever it does.  While this other process is holding the
+** file open, we will be unable to delete it.  To work around this
+** problem, we delay 100 milliseconds and try to delete again.  Up
+** to MX_DELETION_ATTEMPTs deletion attempts are run before giving
+** up and returning an error.
+*/
+static int winDelete(
+  sqlite3_vfs *pVfs,          /* Not used on win32 */
+  const char *zFilename,      /* Name of file to delete */
+  int syncDir                 /* Not used on win32 */
+){
+  int cnt = 0;
+  int rc;
+  DWORD attr;
+  DWORD lastErrno = 0;
+  void *zConverted;
+  UNUSED_PARAMETER(pVfs);
+  UNUSED_PARAMETER(syncDir);
+
+  SimulateIOError(return SQLITE_IOERR_DELETE);
+  OSTRACE(("DELETE name=%s, syncDir=%d\n", zFilename, syncDir));
+
+  zConverted = winConvertFromUtf8Filename(zFilename);
+  if( zConverted==0 ){
+    OSTRACE(("DELETE name=%s, rc=SQLITE_IOERR_NOMEM\n", zFilename));
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+  if( osIsNT() ){
+    do {
+#if SQLITE_OS_WINRT
+      WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+      memset(&sAttrData, 0, sizeof(sAttrData));
+      if ( osGetFileAttributesExW(zConverted, GetFileExInfoStandard,
+                                  &sAttrData) ){
+        attr = sAttrData.dwFileAttributes;
+      }else{
+        lastErrno = osGetLastError();
+        if( lastErrno==ERROR_FILE_NOT_FOUND
+         || lastErrno==ERROR_PATH_NOT_FOUND ){
+          rc = SQLITE_IOERR_DELETE_NOENT; /* Already gone? */
+        }else{
+          rc = SQLITE_ERROR;
+        }
+        break;
+      }
+#else
+      attr = osGetFileAttributesW(zConverted);
+#endif
+      if ( attr==INVALID_FILE_ATTRIBUTES ){
+        lastErrno = osGetLastError();
+        if( lastErrno==ERROR_FILE_NOT_FOUND
+         || lastErrno==ERROR_PATH_NOT_FOUND ){
+          rc = SQLITE_IOERR_DELETE_NOENT; /* Already gone? */
+        }else{
+          rc = SQLITE_ERROR;
+        }
+        break;
+      }
+      if ( attr&FILE_ATTRIBUTE_DIRECTORY ){
+        rc = SQLITE_ERROR; /* Files only. */
+        break;
+      }
+      if ( osDeleteFileW(zConverted) ){
+        rc = SQLITE_OK; /* Deleted OK. */
+        break;
+      }
+      if ( !winRetryIoerr(&cnt, &lastErrno) ){
+        rc = SQLITE_ERROR; /* No more retries. */
+        break;
+      }
+    } while(1);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    do {
+      attr = osGetFileAttributesA(zConverted);
+      if ( attr==INVALID_FILE_ATTRIBUTES ){
+        lastErrno = osGetLastError();
+        if( lastErrno==ERROR_FILE_NOT_FOUND
+         || lastErrno==ERROR_PATH_NOT_FOUND ){
+          rc = SQLITE_IOERR_DELETE_NOENT; /* Already gone? */
+        }else{
+          rc = SQLITE_ERROR;
+        }
+        break;
+      }
+      if ( attr&FILE_ATTRIBUTE_DIRECTORY ){
+        rc = SQLITE_ERROR; /* Files only. */
+        break;
+      }
+      if ( osDeleteFileA(zConverted) ){
+        rc = SQLITE_OK; /* Deleted OK. */
+        break;
+      }
+      if ( !winRetryIoerr(&cnt, &lastErrno) ){
+        rc = SQLITE_ERROR; /* No more retries. */
+        break;
+      }
+    } while(1);
+  }
+#endif
+  if( rc && rc!=SQLITE_IOERR_DELETE_NOENT ){
+    rc = winLogError(SQLITE_IOERR_DELETE, lastErrno, "winDelete", zFilename);
+  }else{
+    winLogIoerr(cnt, __LINE__);
+  }
+  sqlite3_free(zConverted);
+  OSTRACE(("DELETE name=%s, rc=%s\n", zFilename, sqlite3ErrName(rc)));
+  return rc;
+}
+
+/*
+** Check the existence and status of a file.
+*/
+static int winAccess(
+  sqlite3_vfs *pVfs,         /* Not used on win32 */
+  const char *zFilename,     /* Name of file to check */
+  int flags,                 /* Type of test to make on this file */
+  int *pResOut               /* OUT: Result */
+){
+  DWORD attr;
+  int rc = 0;
+  DWORD lastErrno = 0;
+  void *zConverted;
+  UNUSED_PARAMETER(pVfs);
+
+  SimulateIOError( return SQLITE_IOERR_ACCESS; );
+  OSTRACE(("ACCESS name=%s, flags=%x, pResOut=%p\n",
+           zFilename, flags, pResOut));
+
+  if( zFilename==0 ){
+    *pResOut = 0;
+    OSTRACE(("ACCESS name=%s, pResOut=%p, *pResOut=%d, rc=SQLITE_OK\n",
+             zFilename, pResOut, *pResOut));
+    return SQLITE_OK;
+  }
+
+  zConverted = winConvertFromUtf8Filename(zFilename);
+  if( zConverted==0 ){
+    OSTRACE(("ACCESS name=%s, rc=SQLITE_IOERR_NOMEM\n", zFilename));
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+  if( osIsNT() ){
+    int cnt = 0;
+    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+    memset(&sAttrData, 0, sizeof(sAttrData));
+    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
+                             GetFileExInfoStandard,
+                             &sAttrData)) && winRetryIoerr(&cnt, &lastErrno) ){}
+    if( rc ){
+      /* For an SQLITE_ACCESS_EXISTS query, treat a zero-length file
+      ** as if it does not exist.
+      */
+      if(    flags==SQLITE_ACCESS_EXISTS
+          && sAttrData.nFileSizeHigh==0
+          && sAttrData.nFileSizeLow==0 ){
+        attr = INVALID_FILE_ATTRIBUTES;
+      }else{
+        attr = sAttrData.dwFileAttributes;
+      }
+    }else{
+      winLogIoerr(cnt, __LINE__);
+      if( lastErrno!=ERROR_FILE_NOT_FOUND && lastErrno!=ERROR_PATH_NOT_FOUND ){
+        sqlite3_free(zConverted);
+        return winLogError(SQLITE_IOERR_ACCESS, lastErrno, "winAccess",
+                           zFilename);
+      }else{
+        attr = INVALID_FILE_ATTRIBUTES;
+      }
+    }
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    attr = osGetFileAttributesA((char*)zConverted);
+  }
+#endif
+  sqlite3_free(zConverted);
+  switch( flags ){
+    case SQLITE_ACCESS_READ:
+    case SQLITE_ACCESS_EXISTS:
+      rc = attr!=INVALID_FILE_ATTRIBUTES;
+      break;
+    case SQLITE_ACCESS_READWRITE:
+      rc = attr!=INVALID_FILE_ATTRIBUTES &&
+             (attr & FILE_ATTRIBUTE_READONLY)==0;
+      break;
+    default:
+      assert(!"Invalid flags argument");
+  }
+  *pResOut = rc;
+  OSTRACE(("ACCESS name=%s, pResOut=%p, *pResOut=%d, rc=SQLITE_OK\n",
+           zFilename, pResOut, *pResOut));
+  return SQLITE_OK;
+}
+
+/*
+** Returns non-zero if the specified path name starts with the "long path"
+** prefix.
+*/
+static BOOL winIsLongPathPrefix(
+  const char *zPathname
+){
+  return ( zPathname[0]=='\\' && zPathname[1]=='\\'
+        && zPathname[2]=='?'  && zPathname[3]=='\\' );
+}
+
+/*
+** Returns non-zero if the specified path name starts with a drive letter
+** followed by a colon character.
+*/
+static BOOL winIsDriveLetterAndColon(
+  const char *zPathname
+){
+  return ( sqlite3Isalpha(zPathname[0]) && zPathname[1]==':' );
+}
+
+/*
+** Returns non-zero if the specified path name should be used verbatim.  If
+** non-zero is returned from this function, the calling function must simply
+** use the provided path name verbatim -OR- resolve it into a full path name
+** using the GetFullPathName Win32 API function (if available).
+*/
+static BOOL winIsVerbatimPathname(
+  const char *zPathname
+){
+  /*
+  ** If the path name starts with a forward slash or a backslash, it is either
+  ** a legal UNC name, a volume relative path, or an absolute path name in the
+  ** "Unix" format on Windows.  There is no easy way to differentiate between
+  ** the final two cases; therefore, we return the safer return value of TRUE
+  ** so that callers of this function will simply use it verbatim.
+  */
+  if ( winIsDirSep(zPathname[0]) ){
+    return TRUE;
+  }
+
+  /*
+  ** If the path name starts with a letter and a colon it is either a volume
+  ** relative path or an absolute path.  Callers of this function must not
+  ** attempt to treat it as a relative path name (i.e. they should simply use
+  ** it verbatim).
+  */
+  if ( winIsDriveLetterAndColon(zPathname) ){
+    return TRUE;
+  }
+
+  /*
+  ** If we get to this point, the path name should almost certainly be a purely
+  ** relative one (i.e. not a UNC name, not absolute, and not volume relative).
+  */
+  return FALSE;
+}
+
+/*
+** Turn a relative pathname into a full pathname.  Write the full
+** pathname into zOut[].  zOut[] will be at least pVfs->mxPathname
+** bytes in size.
+*/
+static int winFullPathnameNoMutex(
+  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
+  const char *zRelative,        /* Possibly relative input path */
+  int nFull,                    /* Size of output buffer in bytes */
+  char *zFull                   /* Output buffer */
+){
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && !defined(__CYGWIN__)
+  DWORD nByte;
+  void *zConverted;
+  char *zOut;
+#endif
+
+  /* If this path name begins with "/X:" or "\\?\", where "X" is any
+  ** alphabetic character, discard the initial "/" from the pathname.
+  */
+  if( zRelative[0]=='/' && (winIsDriveLetterAndColon(zRelative+1)
+       || winIsLongPathPrefix(zRelative+1)) ){
+    zRelative++;
+  }
+
+#if defined(__CYGWIN__)
+  SimulateIOError( return SQLITE_ERROR );
+  UNUSED_PARAMETER(nFull);
+  assert( nFull>=pVfs->mxPathname );
+  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
+    /*
+    ** NOTE: We are dealing with a relative path name and the data
+    **       directory has been set.  Therefore, use it as the basis
+    **       for converting the relative path name to an absolute
+    **       one by prepending the data directory and a slash.
+    */
+    char *zOut = sqlite3MallocZero( pVfs->mxPathname+1 );
+    if( !zOut ){
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    if( cygwin_conv_path(
+            (osIsNT() ? CCP_POSIX_TO_WIN_W : CCP_POSIX_TO_WIN_A) |
+            CCP_RELATIVE, zRelative, zOut, pVfs->mxPathname+1)<0 ){
+      sqlite3_free(zOut);
+      return winLogError(SQLITE_CANTOPEN_CONVPATH, (DWORD)errno,
+                         "winFullPathname1", zRelative);
+    }else{
+      char *zUtf8 = winConvertToUtf8Filename(zOut);
+      if( !zUtf8 ){
+        sqlite3_free(zOut);
+        return SQLITE_IOERR_NOMEM_BKPT;
+      }
+      sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s%c%s",
+                       sqlite3_data_directory, winGetDirSep(), zUtf8);
+      sqlite3_free(zUtf8);
+      sqlite3_free(zOut);
+    }
+  }else{
+    char *zOut = sqlite3MallocZero( pVfs->mxPathname+1 );
+    if( !zOut ){
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    if( cygwin_conv_path(
+            (osIsNT() ? CCP_POSIX_TO_WIN_W : CCP_POSIX_TO_WIN_A),
+            zRelative, zOut, pVfs->mxPathname+1)<0 ){
+      sqlite3_free(zOut);
+      return winLogError(SQLITE_CANTOPEN_CONVPATH, (DWORD)errno,
+                         "winFullPathname2", zRelative);
+    }else{
+      char *zUtf8 = winConvertToUtf8Filename(zOut);
+      if( !zUtf8 ){
+        sqlite3_free(zOut);
+        return SQLITE_IOERR_NOMEM_BKPT;
+      }
+      sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zUtf8);
+      sqlite3_free(zUtf8);
+      sqlite3_free(zOut);
+    }
+  }
+  return SQLITE_OK;
+#endif
+
+#if (SQLITE_OS_WINCE || SQLITE_OS_WINRT) && !defined(__CYGWIN__)
+  SimulateIOError( return SQLITE_ERROR );
+  /* WinCE has no concept of a relative pathname, or so I am told. */
+  /* WinRT has no way to convert a relative path to an absolute one. */
+  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
+    /*
+    ** NOTE: We are dealing with a relative path name and the data
+    **       directory has been set.  Therefore, use it as the basis
+    **       for converting the relative path name to an absolute
+    **       one by prepending the data directory and a backslash.
+    */
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s%c%s",
+                     sqlite3_data_directory, winGetDirSep(), zRelative);
+  }else{
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zRelative);
+  }
+  return SQLITE_OK;
+#endif
+
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && !defined(__CYGWIN__)
+  /* It's odd to simulate an io-error here, but really this is just
+  ** using the io-error infrastructure to test that SQLite handles this
+  ** function failing. This function could fail if, for example, the
+  ** current working directory has been unlinked.
+  */
+  SimulateIOError( return SQLITE_ERROR );
+  if ( sqlite3_data_directory && !winIsVerbatimPathname(zRelative) ){
+    /*
+    ** NOTE: We are dealing with a relative path name and the data
+    **       directory has been set.  Therefore, use it as the basis
+    **       for converting the relative path name to an absolute
+    **       one by prepending the data directory and a backslash.
+    */
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s%c%s",
+                     sqlite3_data_directory, winGetDirSep(), zRelative);
+    return SQLITE_OK;
+  }
+  zConverted = winConvertFromUtf8Filename(zRelative);
+  if( zConverted==0 ){
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+  if( osIsNT() ){
+    LPWSTR zTemp;
+    nByte = osGetFullPathNameW((LPCWSTR)zConverted, 0, 0, 0);
+    if( nByte==0 ){
+      sqlite3_free(zConverted);
+      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
+                         "winFullPathname1", zRelative);
+    }
+    nByte += 3;
+    zTemp = sqlite3MallocZero( nByte*sizeof(zTemp[0]) );
+    if( zTemp==0 ){
+      sqlite3_free(zConverted);
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    nByte = osGetFullPathNameW((LPCWSTR)zConverted, nByte, zTemp, 0);
+    if( nByte==0 ){
+      sqlite3_free(zConverted);
+      sqlite3_free(zTemp);
+      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
+                         "winFullPathname2", zRelative);
+    }
+    sqlite3_free(zConverted);
+    zOut = winUnicodeToUtf8(zTemp);
+    sqlite3_free(zTemp);
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    char *zTemp;
+    nByte = osGetFullPathNameA((char*)zConverted, 0, 0, 0);
+    if( nByte==0 ){
+      sqlite3_free(zConverted);
+      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
+                         "winFullPathname3", zRelative);
+    }
+    nByte += 3;
+    zTemp = sqlite3MallocZero( nByte*sizeof(zTemp[0]) );
+    if( zTemp==0 ){
+      sqlite3_free(zConverted);
+      return SQLITE_IOERR_NOMEM_BKPT;
+    }
+    nByte = osGetFullPathNameA((char*)zConverted, nByte, zTemp, 0);
+    if( nByte==0 ){
+      sqlite3_free(zConverted);
+      sqlite3_free(zTemp);
+      return winLogError(SQLITE_CANTOPEN_FULLPATH, osGetLastError(),
+                         "winFullPathname4", zRelative);
+    }
+    sqlite3_free(zConverted);
+    zOut = winMbcsToUtf8(zTemp, osAreFileApisANSI());
+    sqlite3_free(zTemp);
+  }
+#endif
+  if( zOut ){
+    sqlite3_snprintf(MIN(nFull, pVfs->mxPathname), zFull, "%s", zOut);
+    sqlite3_free(zOut);
+    return SQLITE_OK;
+  }else{
+    return SQLITE_IOERR_NOMEM_BKPT;
+  }
+#endif
+}
+static int winFullPathname(
+  sqlite3_vfs *pVfs,            /* Pointer to vfs object */
+  const char *zRelative,        /* Possibly relative input path */
+  int nFull,                    /* Size of output buffer in bytes */
+  char *zFull                   /* Output buffer */
+){
+  int rc;
+  MUTEX_LOGIC( sqlite3_mutex *pMutex; )
+  MUTEX_LOGIC( pMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR); )
+  sqlite3_mutex_enter(pMutex);
+  rc = winFullPathnameNoMutex(pVfs, zRelative, nFull, zFull);
+  sqlite3_mutex_leave(pMutex);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Interfaces for opening a shared library, finding entry points
+** within the shared library, and closing the shared library.
+*/
+static void *winDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
+  HANDLE h;
+#if defined(__CYGWIN__)
+  int nFull = pVfs->mxPathname+1;
+  char *zFull = sqlite3MallocZero( nFull );
+  void *zConverted = 0;
+  if( zFull==0 ){
+    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
+    return 0;
+  }
+  if( winFullPathname(pVfs, zFilename, nFull, zFull)!=SQLITE_OK ){
+    sqlite3_free(zFull);
+    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
+    return 0;
+  }
+  zConverted = winConvertFromUtf8Filename(zFull);
+  sqlite3_free(zFull);
+#else
+  void *zConverted = winConvertFromUtf8Filename(zFilename);
+  UNUSED_PARAMETER(pVfs);
+#endif
+  if( zConverted==0 ){
+    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
+    return 0;
+  }
+  if( osIsNT() ){
+#if SQLITE_OS_WINRT
+    h = osLoadPackagedLibrary((LPCWSTR)zConverted, 0);
+#else
+    h = osLoadLibraryW((LPCWSTR)zConverted);
+#endif
+  }
+#ifdef SQLITE_WIN32_HAS_ANSI
+  else{
+    h = osLoadLibraryA((char*)zConverted);
+  }
+#endif
+  OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)h));
+  sqlite3_free(zConverted);
+  return (void*)h;
+}
+static void winDlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
+  UNUSED_PARAMETER(pVfs);
+  winGetLastErrorMsg(osGetLastError(), nBuf, zBufOut);
+}
+static void (*winDlSym(sqlite3_vfs *pVfs,void *pH,const char *zSym))(void){
+  FARPROC proc;
+  UNUSED_PARAMETER(pVfs);
+  proc = osGetProcAddressA((HANDLE)pH, zSym);
+  OSTRACE(("DLSYM handle=%p, symbol=%s, address=%p\n",
+           (void*)pH, zSym, (void*)proc));
+  return (void(*)(void))proc;
+}
+static void winDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  UNUSED_PARAMETER(pVfs);
+  osFreeLibrary((HANDLE)pHandle);
+  OSTRACE(("DLCLOSE handle=%p\n", (void*)pHandle));
+}
+#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
+  #define winDlOpen  0
+  #define winDlError 0
+  #define winDlSym   0
+  #define winDlClose 0
+#endif
+
+/* State information for the randomness gatherer. */
+typedef struct EntropyGatherer EntropyGatherer;
+struct EntropyGatherer {
+  unsigned char *a;   /* Gather entropy into this buffer */
+  int na;             /* Size of a[] in bytes */
+  int i;              /* XOR next input into a[i] */
+  int nXor;           /* Number of XOR operations done */
+};
+
+#if !defined(SQLITE_TEST) && !defined(SQLITE_OMIT_RANDOMNESS)
+/* Mix sz bytes of entropy into p. */
+static void xorMemory(EntropyGatherer *p, unsigned char *x, int sz){
+  int j, k;
+  for(j=0, k=p->i; j<sz; j++){
+    p->a[k++] ^= x[j];
+    if( k>=p->na ) k = 0;
+  }
+  p->i = k;
+  p->nXor += sz;
+}
+#endif /* !defined(SQLITE_TEST) && !defined(SQLITE_OMIT_RANDOMNESS) */
+
+/*
+** Write up to nBuf bytes of randomness into zBuf.
+*/
+static int winRandomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+#if defined(SQLITE_TEST) || defined(SQLITE_OMIT_RANDOMNESS)
+  UNUSED_PARAMETER(pVfs);
+  memset(zBuf, 0, nBuf);
+  return nBuf;
+#else
+  EntropyGatherer e;
+  UNUSED_PARAMETER(pVfs);
+  memset(zBuf, 0, nBuf);
+  e.a = (unsigned char*)zBuf;
+  e.na = nBuf;
+  e.nXor = 0;
+  e.i = 0;
+  {
+    SYSTEMTIME x;
+    osGetSystemTime(&x);
+    xorMemory(&e, (unsigned char*)&x, sizeof(SYSTEMTIME));
+  }
+  {
+    DWORD pid = osGetCurrentProcessId();
+    xorMemory(&e, (unsigned char*)&pid, sizeof(DWORD));
+  }
+#if SQLITE_OS_WINRT
+  {
+    ULONGLONG cnt = osGetTickCount64();
+    xorMemory(&e, (unsigned char*)&cnt, sizeof(ULONGLONG));
+  }
+#else
+  {
+    DWORD cnt = osGetTickCount();
+    xorMemory(&e, (unsigned char*)&cnt, sizeof(DWORD));
+  }
+#endif /* SQLITE_OS_WINRT */
+  {
+    LARGE_INTEGER i;
+    osQueryPerformanceCounter(&i);
+    xorMemory(&e, (unsigned char*)&i, sizeof(LARGE_INTEGER));
+  }
+#if !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_WIN32_USE_UUID
+  {
+    UUID id;
+    memset(&id, 0, sizeof(UUID));
+    osUuidCreate(&id);
+    xorMemory(&e, (unsigned char*)&id, sizeof(UUID));
+    memset(&id, 0, sizeof(UUID));
+    osUuidCreateSequential(&id);
+    xorMemory(&e, (unsigned char*)&id, sizeof(UUID));
+  }
+#endif /* !SQLITE_OS_WINCE && !SQLITE_OS_WINRT && SQLITE_WIN32_USE_UUID */
+  return e.nXor>nBuf ? nBuf : e.nXor;
+#endif /* defined(SQLITE_TEST) || defined(SQLITE_OMIT_RANDOMNESS) */
+}
+
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+*/
+static int winSleep(sqlite3_vfs *pVfs, int microsec){
+  sqlite3_win32_sleep((microsec+999)/1000);
+  UNUSED_PARAMETER(pVfs);
+  return ((microsec+999)/1000)*1000;
+}
+
+/*
+** The following variable, if set to a non-zero value, is interpreted as
+** the number of seconds since 1970 and is used to set the result of
+** sqlite3OsCurrentTime() during testing.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_current_time = 0;  /* Fake system time in seconds since 1970. */
+#endif
+
+/*
+** Find the current time (in Universal Coordinated Time).  Write into *piNow
+** the current time and date as a Julian Day number times 86_400_000.  In
+** other words, write into *piNow the number of milliseconds since the Julian
+** epoch of noon in Greenwich on November 24, 4714 B.C according to the
+** proleptic Gregorian calendar.
+**
+** On success, return SQLITE_OK.  Return SQLITE_ERROR if the time and date
+** cannot be found.
+*/
+static int winCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *piNow){
+  /* FILETIME structure is a 64-bit value representing the number of
+     100-nanosecond intervals since January 1, 1601 (= JD 2305813.5).
+  */
+  FILETIME ft;
+  static const sqlite3_int64 winFiletimeEpoch = 23058135*(sqlite3_int64)8640000;
+#ifdef SQLITE_TEST
+  static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+#endif
+  /* 2^32 - to avoid use of LL and warnings in gcc */
+  static const sqlite3_int64 max32BitValue =
+      (sqlite3_int64)2000000000 + (sqlite3_int64)2000000000 +
+      (sqlite3_int64)294967296;
+
+#if SQLITE_OS_WINCE
+  SYSTEMTIME time;
+  osGetSystemTime(&time);
+  /* if SystemTimeToFileTime() fails, it returns zero. */
+  if (!osSystemTimeToFileTime(&time,&ft)){
+    return SQLITE_ERROR;
+  }
+#else
+  osGetSystemTimeAsFileTime( &ft );
+#endif
+
+  *piNow = winFiletimeEpoch +
+            ((((sqlite3_int64)ft.dwHighDateTime)*max32BitValue) +
+               (sqlite3_int64)ft.dwLowDateTime)/(sqlite3_int64)10000;
+
+#ifdef SQLITE_TEST
+  if( sqlite3_current_time ){
+    *piNow = 1000*(sqlite3_int64)sqlite3_current_time + unixEpoch;
+  }
+#endif
+  UNUSED_PARAMETER(pVfs);
+  return SQLITE_OK;
+}
+
+/*
+** Find the current time (in Universal Coordinated Time).  Write the
+** current time and date as a Julian Day number into *prNow and
+** return 0.  Return 1 if the time and date cannot be found.
+*/
+static int winCurrentTime(sqlite3_vfs *pVfs, double *prNow){
+  int rc;
+  sqlite3_int64 i;
+  rc = winCurrentTimeInt64(pVfs, &i);
+  if( !rc ){
+    *prNow = i/86400000.0;
+  }
+  return rc;
+}
+
+/*
+** The idea is that this function works like a combination of
+** GetLastError() and FormatMessage() on Windows (or errno and
+** strerror_r() on Unix). After an error is returned by an OS
+** function, SQLite calls this function with zBuf pointing to
+** a buffer of nBuf bytes. The OS layer should populate the
+** buffer with a nul-terminated UTF-8 encoded error message
+** describing the last IO error to have occurred within the calling
+** thread.
+**
+** If the error message is too large for the supplied buffer,
+** it should be truncated. The return value of xGetLastError
+** is zero if the error message fits in the buffer, or non-zero
+** otherwise (if the message was truncated). If non-zero is returned,
+** then it is not necessary to include the nul-terminator character
+** in the output buffer.
+**
+** Not supplying an error message will have no adverse effect
+** on SQLite. It is fine to have an implementation that never
+** returns an error message:
+**
+**   int xGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+**     assert(zBuf[0]=='\0');
+**     return 0;
+**   }
+**
+** However if an error message is supplied, it will be incorporated
+** by sqlite into the error message available to the user using
+** sqlite3_errmsg(), possibly making IO errors easier to debug.
+*/
+static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
+  DWORD e = osGetLastError();
+  UNUSED_PARAMETER(pVfs);
+  if( nBuf>0 ) winGetLastErrorMsg(e, nBuf, zBuf);
+  return e;
+}
+
+/*
+** Initialize and deinitialize the operating system interface.
+*/
+SQLITE_API int sqlite3_os_init(void){
+  static sqlite3_vfs winVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WIN32_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32",               /* zName */
+    &winAppData,           /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  static sqlite3_vfs winLongPathVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WINNT_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32-longpath",      /* zName */
+    &winAppData,           /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#endif
+  static sqlite3_vfs winNolockVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WIN32_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32-none",          /* zName */
+    &winNolockAppData,     /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  static sqlite3_vfs winLongPathNolockVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WINNT_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32-longpath-none", /* zName */
+    &winNolockAppData,     /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#endif
+
+  /* Double-check that the aSyscall[] array has been constructed
+  ** correctly.  See ticket [bb3a86e890c8e96ab] */
+  assert( ArraySize(aSyscall)==80 );
+
+  /* get memory map allocation granularity */
+  memset(&winSysInfo, 0, sizeof(SYSTEM_INFO));
+#if SQLITE_OS_WINRT
+  osGetNativeSystemInfo(&winSysInfo);
+#else
+  osGetSystemInfo(&winSysInfo);
+#endif
+  assert( winSysInfo.dwAllocationGranularity>0 );
+  assert( winSysInfo.dwPageSize>0 );
+
+  sqlite3_vfs_register(&winVfs, 1);
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  sqlite3_vfs_register(&winLongPathVfs, 0);
+#endif
+
+  sqlite3_vfs_register(&winNolockVfs, 0);
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  sqlite3_vfs_register(&winLongPathNolockVfs, 0);
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+  winBigLock = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
+#endif
+
+  return SQLITE_OK;
+}
+
+SQLITE_API int sqlite3_os_end(void){
+#if SQLITE_OS_WINRT
+  if( sleepObj!=NULL ){
+    osCloseHandle(sleepObj);
+    sleepObj = NULL;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+  winBigLock = 0;
+#endif
+
+  return SQLITE_OK;
+}
+
+#endif /* SQLITE_OS_WIN */
+
+/************** End of os_win.c **********************************************/
+/************** Begin file memdb.c *******************************************/
+/*
+** 2016-09-07
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file implements an in-memory VFS. A database is held as a contiguous
+** block of memory.
+**
+** This file also implements interface sqlite3_serialize() and
+** sqlite3_deserialize().
+*/
+/* #include "sqliteInt.h" */
+#ifndef SQLITE_OMIT_DESERIALIZE
+
+/*
+** Forward declaration of objects used by this utility
+*/
+typedef struct sqlite3_vfs MemVfs;
+typedef struct MemFile MemFile;
+typedef struct MemStore MemStore;
+
+/* Access to a lower-level VFS that (might) implement dynamic loading,
+** access to randomness, etc.
+*/
+#define ORIGVFS(p) ((sqlite3_vfs*)((p)->pAppData))
+
+/* Storage for a memdb file.
+**
+** An memdb object can be shared or separate.  Shared memdb objects can be
+** used by more than one database connection.  Mutexes are used by shared
+** memdb objects to coordinate access.  Separate memdb objects are only
+** connected to a single database connection and do not require additional
+** mutexes.
+**
+** Shared memdb objects have .zFName!=0 and .pMutex!=0.  They are created
+** using "file:/name?vfs=memdb".  The first character of the name must be
+** "/" or else the object will be a separate memdb object.  All shared
+** memdb objects are stored in memdb_g.apMemStore[] in an arbitrary order.
+**
+** Separate memdb objects are created using a name that does not begin
+** with "/" or using sqlite3_deserialize().
+**
+** Access rules for shared MemStore objects:
+**
+**   *  .zFName is initialized when the object is created and afterwards
+**      is unchanged until the object is destroyed.  So it can be accessed
+**      at any time as long as we know the object is not being destroyed,
+**      which means while either the SQLITE_MUTEX_STATIC_VFS1 or
+**      .pMutex is held or the object is not part of memdb_g.apMemStore[].
+**
+**   *  Can .pMutex can only be changed while holding the
+**      SQLITE_MUTEX_STATIC_VFS1 mutex or while the object is not part
+**      of memdb_g.apMemStore[].
+**
+**   *  Other fields can only be changed while holding the .pMutex mutex
+**      or when the .nRef is less than zero and the object is not part of
+**      memdb_g.apMemStore[].
+**
+**   *  The .aData pointer has the added requirement that it can can only
+**      be changed (for resizing) when nMmap is zero.
+**
+*/
+struct MemStore {
+  sqlite3_int64 sz;               /* Size of the file */
+  sqlite3_int64 szAlloc;          /* Space allocated to aData */
+  sqlite3_int64 szMax;            /* Maximum allowed size of the file */
+  unsigned char *aData;           /* content of the file */
+  sqlite3_mutex *pMutex;          /* Used by shared stores only */
+  int nMmap;                      /* Number of memory mapped pages */
+  unsigned mFlags;                /* Flags */
+  int nRdLock;                    /* Number of readers */
+  int nWrLock;                    /* Number of writers.  (Always 0 or 1) */
+  int nRef;                       /* Number of users of this MemStore */
+  char *zFName;                   /* The filename for shared stores */
+};
+
+/* An open file */
+struct MemFile {
+  sqlite3_file base;              /* IO methods */
+  MemStore *pStore;               /* The storage */
+  int eLock;                      /* Most recent lock against this file */
+};
+
+/*
+** File-scope variables for holding the memdb files that are accessible
+** to multiple database connections in separate threads.
+**
+** Must hold SQLITE_MUTEX_STATIC_VFS1 to access any part of this object.
+*/
+static struct MemFS {
+  int nMemStore;                  /* Number of shared MemStore objects */
+  MemStore **apMemStore;          /* Array of all shared MemStore objects */
+} memdb_g;
+
+/*
+** Methods for MemFile
+*/
+static int memdbClose(sqlite3_file*);
+static int memdbRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int memdbWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
+static int memdbTruncate(sqlite3_file*, sqlite3_int64 size);
+static int memdbSync(sqlite3_file*, int flags);
+static int memdbFileSize(sqlite3_file*, sqlite3_int64 *pSize);
+static int memdbLock(sqlite3_file*, int);
+static int memdbUnlock(sqlite3_file*, int);
+/* static int memdbCheckReservedLock(sqlite3_file*, int *pResOut);// not used */
+static int memdbFileControl(sqlite3_file*, int op, void *pArg);
+/* static int memdbSectorSize(sqlite3_file*); // not used */
+static int memdbDeviceCharacteristics(sqlite3_file*);
+static int memdbFetch(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
+static int memdbUnfetch(sqlite3_file*, sqlite3_int64 iOfst, void *p);
+
+/*
+** Methods for MemVfs
+*/
+static int memdbOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
+/* static int memdbDelete(sqlite3_vfs*, const char *zName, int syncDir); */
+static int memdbAccess(sqlite3_vfs*, const char *zName, int flags, int *);
+static int memdbFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
+static void *memdbDlOpen(sqlite3_vfs*, const char *zFilename);
+static void memdbDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
+static void (*memdbDlSym(sqlite3_vfs *pVfs, void *p, const char*zSym))(void);
+static void memdbDlClose(sqlite3_vfs*, void*);
+static int memdbRandomness(sqlite3_vfs*, int nByte, char *zOut);
+static int memdbSleep(sqlite3_vfs*, int microseconds);
+/* static int memdbCurrentTime(sqlite3_vfs*, double*); */
+static int memdbGetLastError(sqlite3_vfs*, int, char *);
+static int memdbCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
+
+static sqlite3_vfs memdb_vfs = {
+  2,                           /* iVersion */
+  0,                           /* szOsFile (set when registered) */
+  1024,                        /* mxPathname */
+  0,                           /* pNext */
+  "memdb",                     /* zName */
+  0,                           /* pAppData (set when registered) */
+  memdbOpen,                   /* xOpen */
+  0, /* memdbDelete, */        /* xDelete */
+  memdbAccess,                 /* xAccess */
+  memdbFullPathname,           /* xFullPathname */
+  memdbDlOpen,                 /* xDlOpen */
+  memdbDlError,                /* xDlError */
+  memdbDlSym,                  /* xDlSym */
+  memdbDlClose,                /* xDlClose */
+  memdbRandomness,             /* xRandomness */
+  memdbSleep,                  /* xSleep */
+  0, /* memdbCurrentTime, */   /* xCurrentTime */
+  memdbGetLastError,           /* xGetLastError */
+  memdbCurrentTimeInt64,       /* xCurrentTimeInt64 */
+  0,                           /* xSetSystemCall */
+  0,                           /* xGetSystemCall */
+  0,                           /* xNextSystemCall */
+};
+
+static const sqlite3_io_methods memdb_io_methods = {
+  3,                              /* iVersion */
+  memdbClose,                      /* xClose */
+  memdbRead,                       /* xRead */
+  memdbWrite,                      /* xWrite */
+  memdbTruncate,                   /* xTruncate */
+  memdbSync,                       /* xSync */
+  memdbFileSize,                   /* xFileSize */
+  memdbLock,                       /* xLock */
+  memdbUnlock,                     /* xUnlock */
+  0, /* memdbCheckReservedLock, */ /* xCheckReservedLock */
+  memdbFileControl,                /* xFileControl */
+  0, /* memdbSectorSize,*/         /* xSectorSize */
+  memdbDeviceCharacteristics,      /* xDeviceCharacteristics */
+  0,                               /* xShmMap */
+  0,                               /* xShmLock */
+  0,                               /* xShmBarrier */
+  0,                               /* xShmUnmap */
+  memdbFetch,                      /* xFetch */
+  memdbUnfetch                     /* xUnfetch */
+};
+
+/*
+** Enter/leave the mutex on a MemStore
+*/
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE==0
+static void memdbEnter(MemStore *p){
+  UNUSED_PARAMETER(p);
+}
+static void memdbLeave(MemStore *p){
+  UNUSED_PARAMETER(p);
+}
+#else
+static void memdbEnter(MemStore *p){
+  sqlite3_mutex_enter(p->pMutex);
+}
+static void memdbLeave(MemStore *p){
+  sqlite3_mutex_leave(p->pMutex);
+}
+#endif
+
+
+
+/*
+** Close an memdb-file.
+** Free the underlying MemStore object when its refcount drops to zero
+** or less.
+*/
+static int memdbClose(sqlite3_file *pFile){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  if( p->zFName ){
+    int i;
+#ifndef SQLITE_MUTEX_OMIT
+    sqlite3_mutex *pVfsMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
+#endif
+    sqlite3_mutex_enter(pVfsMutex);
+    for(i=0; ALWAYS(i<memdb_g.nMemStore); i++){
+      if( memdb_g.apMemStore[i]==p ){
+        memdbEnter(p);
+        if( p->nRef==1 ){
+          memdb_g.apMemStore[i] = memdb_g.apMemStore[--memdb_g.nMemStore];
+          if( memdb_g.nMemStore==0 ){
+            sqlite3_free(memdb_g.apMemStore);
+            memdb_g.apMemStore = 0;
+          }
+        }
+        break;
+      }
+    }
+    sqlite3_mutex_leave(pVfsMutex);
+  }else{
+    memdbEnter(p);
+  }
+  p->nRef--;
+  if( p->nRef<=0 ){
+    if( p->mFlags & SQLITE_DESERIALIZE_FREEONCLOSE ){
+      sqlite3_free(p->aData);
+    }
+    memdbLeave(p);
+    sqlite3_mutex_free(p->pMutex);
+    sqlite3_free(p);
+  }else{
+    memdbLeave(p);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Read data from an memdb-file.
+*/
+static int memdbRead(
+  sqlite3_file *pFile,
+  void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  memdbEnter(p);
+  if( iOfst+iAmt>p->sz ){
+    memset(zBuf, 0, iAmt);
+    if( iOfst<p->sz ) memcpy(zBuf, p->aData+iOfst, p->sz - iOfst);
+    memdbLeave(p);
+    return SQLITE_IOERR_SHORT_READ;
+  }
+  memcpy(zBuf, p->aData+iOfst, iAmt);
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Try to enlarge the memory allocation to hold at least sz bytes
+*/
+static int memdbEnlarge(MemStore *p, sqlite3_int64 newSz){
+  unsigned char *pNew;
+  if( (p->mFlags & SQLITE_DESERIALIZE_RESIZEABLE)==0 || NEVER(p->nMmap>0) ){
+    return SQLITE_FULL;
+  }
+  if( newSz>p->szMax ){
+    return SQLITE_FULL;
+  }
+  newSz *= 2;
+  if( newSz>p->szMax ) newSz = p->szMax;
+  pNew = sqlite3Realloc(p->aData, newSz);
+  if( pNew==0 ) return SQLITE_IOERR_NOMEM;
+  p->aData = pNew;
+  p->szAlloc = newSz;
+  return SQLITE_OK;
+}
+
+/*
+** Write data to an memdb-file.
+*/
+static int memdbWrite(
+  sqlite3_file *pFile,
+  const void *z,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  memdbEnter(p);
+  if( NEVER(p->mFlags & SQLITE_DESERIALIZE_READONLY) ){
+    /* Can't happen: memdbLock() will return SQLITE_READONLY before
+    ** reaching this point */
+    memdbLeave(p);
+    return SQLITE_IOERR_WRITE;
+  }
+  if( iOfst+iAmt>p->sz ){
+    int rc;
+    if( iOfst+iAmt>p->szAlloc
+     && (rc = memdbEnlarge(p, iOfst+iAmt))!=SQLITE_OK
+    ){
+      memdbLeave(p);
+      return rc;
+    }
+    if( iOfst>p->sz ) memset(p->aData+p->sz, 0, iOfst-p->sz);
+    p->sz = iOfst+iAmt;
+  }
+  memcpy(p->aData+iOfst, z, iAmt);
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Truncate an memdb-file.
+**
+** In rollback mode (which is always the case for memdb, as it does not
+** support WAL mode) the truncate() method is only used to reduce
+** the size of a file, never to increase the size.
+*/
+static int memdbTruncate(sqlite3_file *pFile, sqlite_int64 size){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  int rc = SQLITE_OK;
+  memdbEnter(p);
+  if( size>p->sz ){
+    /* This can only happen with a corrupt wal mode db */
+    rc = SQLITE_CORRUPT;
+  }else{
+    p->sz = size;
+  }
+  memdbLeave(p);
+  return rc;
+}
+
+/*
+** Sync an memdb-file.
+*/
+static int memdbSync(sqlite3_file *pFile, int flags){
+  UNUSED_PARAMETER(pFile);
+  UNUSED_PARAMETER(flags);
+  return SQLITE_OK;
+}
+
+/*
+** Return the current file-size of an memdb-file.
+*/
+static int memdbFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  memdbEnter(p);
+  *pSize = p->sz;
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Lock an memdb-file.
+*/
+static int memdbLock(sqlite3_file *pFile, int eLock){
+  MemFile *pThis = (MemFile*)pFile;
+  MemStore *p = pThis->pStore;
+  int rc = SQLITE_OK;
+  if( eLock<=pThis->eLock ) return SQLITE_OK;
+  memdbEnter(p);
+
+  assert( p->nWrLock==0 || p->nWrLock==1 );
+  assert( pThis->eLock<=SQLITE_LOCK_SHARED || p->nWrLock==1 );
+  assert( pThis->eLock==SQLITE_LOCK_NONE || p->nRdLock>=1 );
+
+  if( eLock>SQLITE_LOCK_SHARED && (p->mFlags & SQLITE_DESERIALIZE_READONLY) ){
+    rc = SQLITE_READONLY;
+  }else{
+    switch( eLock ){
+      case SQLITE_LOCK_SHARED: {
+        assert( pThis->eLock==SQLITE_LOCK_NONE );
+        if( p->nWrLock>0 ){
+          rc = SQLITE_BUSY;
+        }else{
+          p->nRdLock++;
+        }
+        break;
+      };
+
+      case SQLITE_LOCK_RESERVED:
+      case SQLITE_LOCK_PENDING: {
+        assert( pThis->eLock>=SQLITE_LOCK_SHARED );
+        if( ALWAYS(pThis->eLock==SQLITE_LOCK_SHARED) ){
+          if( p->nWrLock>0 ){
+            rc = SQLITE_BUSY;
+          }else{
+            p->nWrLock = 1;
+          }
+        }
+        break;
+      }
+
+      default: {
+        assert(  eLock==SQLITE_LOCK_EXCLUSIVE );
+        assert( pThis->eLock>=SQLITE_LOCK_SHARED );
+        if( p->nRdLock>1 ){
+          rc = SQLITE_BUSY;
+        }else if( pThis->eLock==SQLITE_LOCK_SHARED ){
+          p->nWrLock = 1;
+        }
+        break;
+      }
+    }
+  }
+  if( rc==SQLITE_OK ) pThis->eLock = eLock;
+  memdbLeave(p);
+  return rc;
+}
+
+/*
+** Unlock an memdb-file.
+*/
+static int memdbUnlock(sqlite3_file *pFile, int eLock){
+  MemFile *pThis = (MemFile*)pFile;
+  MemStore *p = pThis->pStore;
+  if( eLock>=pThis->eLock ) return SQLITE_OK;
+  memdbEnter(p);
+
+  assert( eLock==SQLITE_LOCK_SHARED || eLock==SQLITE_LOCK_NONE );
+  if( eLock==SQLITE_LOCK_SHARED ){
+    if( ALWAYS(pThis->eLock>SQLITE_LOCK_SHARED) ){
+      p->nWrLock--;
+    }
+  }else{
+    if( pThis->eLock>SQLITE_LOCK_SHARED ){
+      p->nWrLock--;
+    }
+    p->nRdLock--;
+  }
+
+  pThis->eLock = eLock;
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+#if 0
+/*
+** This interface is only used for crash recovery, which does not
+** occur on an in-memory database.
+*/
+static int memdbCheckReservedLock(sqlite3_file *pFile, int *pResOut){
+  *pResOut = 0;
+  return SQLITE_OK;
+}
+#endif
+
+
+/*
+** File control method. For custom operations on an memdb-file.
+*/
+static int memdbFileControl(sqlite3_file *pFile, int op, void *pArg){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  int rc = SQLITE_NOTFOUND;
+  memdbEnter(p);
+  if( op==SQLITE_FCNTL_VFSNAME ){
+    *(char**)pArg = sqlite3_mprintf("memdb(%p,%lld)", p->aData, p->sz);
+    rc = SQLITE_OK;
+  }
+  if( op==SQLITE_FCNTL_SIZE_LIMIT ){
+    sqlite3_int64 iLimit = *(sqlite3_int64*)pArg;
+    if( iLimit<p->sz ){
+      if( iLimit<0 ){
+        iLimit = p->szMax;
+      }else{
+        iLimit = p->sz;
+      }
+    }
+    p->szMax = iLimit;
+    *(sqlite3_int64*)pArg = iLimit;
+    rc = SQLITE_OK;
+  }
+  memdbLeave(p);
+  return rc;
+}
+
+#if 0  /* Not used because of SQLITE_IOCAP_POWERSAFE_OVERWRITE */
+/*
+** Return the sector-size in bytes for an memdb-file.
+*/
+static int memdbSectorSize(sqlite3_file *pFile){
+  return 1024;
+}
+#endif
+
+/*
+** Return the device characteristic flags supported by an memdb-file.
+*/
+static int memdbDeviceCharacteristics(sqlite3_file *pFile){
+  UNUSED_PARAMETER(pFile);
+  return SQLITE_IOCAP_ATOMIC |
+         SQLITE_IOCAP_POWERSAFE_OVERWRITE |
+         SQLITE_IOCAP_SAFE_APPEND |
+         SQLITE_IOCAP_SEQUENTIAL;
+}
+
+/* Fetch a page of a memory-mapped file */
+static int memdbFetch(
+  sqlite3_file *pFile,
+  sqlite3_int64 iOfst,
+  int iAmt,
+  void **pp
+){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  memdbEnter(p);
+  if( iOfst+iAmt>p->sz || (p->mFlags & SQLITE_DESERIALIZE_RESIZEABLE)!=0 ){
+    *pp = 0;
+  }else{
+    p->nMmap++;
+    *pp = (void*)(p->aData + iOfst);
+  }
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/* Release a memory-mapped page */
+static int memdbUnfetch(sqlite3_file *pFile, sqlite3_int64 iOfst, void *pPage){
+  MemStore *p = ((MemFile*)pFile)->pStore;
+  UNUSED_PARAMETER(iOfst);
+  UNUSED_PARAMETER(pPage);
+  memdbEnter(p);
+  p->nMmap--;
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Open an mem file handle.
+*/
+static int memdbOpen(
+  sqlite3_vfs *pVfs,
+  const char *zName,
+  sqlite3_file *pFd,
+  int flags,
+  int *pOutFlags
+){
+  MemFile *pFile = (MemFile*)pFd;
+  MemStore *p = 0;
+  int szName;
+  UNUSED_PARAMETER(pVfs);
+
+  memset(pFile, 0, sizeof(*pFile));
+  szName = sqlite3Strlen30(zName);
+  if( szName>1 && (zName[0]=='/' || zName[0]=='\\') ){
+    int i;
+#ifndef SQLITE_MUTEX_OMIT
+    sqlite3_mutex *pVfsMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1);
+#endif
+    sqlite3_mutex_enter(pVfsMutex);
+    for(i=0; i<memdb_g.nMemStore; i++){
+      if( strcmp(memdb_g.apMemStore[i]->zFName,zName)==0 ){
+        p = memdb_g.apMemStore[i];
+        break;
+      }
+    }
+    if( p==0 ){
+      MemStore **apNew;
+      p = sqlite3Malloc( sizeof(*p) + szName + 3 );
+      if( p==0 ){
+        sqlite3_mutex_leave(pVfsMutex);
+        return SQLITE_NOMEM;
+      }
+      apNew = sqlite3Realloc(memdb_g.apMemStore,
+                             sizeof(apNew[0])*(memdb_g.nMemStore+1) );
+      if( apNew==0 ){
+        sqlite3_free(p);
+        sqlite3_mutex_leave(pVfsMutex);
+        return SQLITE_NOMEM;
+      }
+      apNew[memdb_g.nMemStore++] = p;
+      memdb_g.apMemStore = apNew;
+      memset(p, 0, sizeof(*p));
+      p->mFlags = SQLITE_DESERIALIZE_RESIZEABLE|SQLITE_DESERIALIZE_FREEONCLOSE;
+      p->szMax = sqlite3GlobalConfig.mxMemdbSize;
+      p->zFName = (char*)&p[1];
+      memcpy(p->zFName, zName, szName+1);
+      p->pMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+      if( p->pMutex==0 ){
+        memdb_g.nMemStore--;
+        sqlite3_free(p);
+        sqlite3_mutex_leave(pVfsMutex);
+        return SQLITE_NOMEM;
+      }
+      p->nRef = 1;
+      memdbEnter(p);
+    }else{
+      memdbEnter(p);
+      p->nRef++;
+    }
+    sqlite3_mutex_leave(pVfsMutex);
+  }else{
+    p = sqlite3Malloc( sizeof(*p) );
+    if( p==0 ){
+      return SQLITE_NOMEM;
+    }
+    memset(p, 0, sizeof(*p));
+    p->mFlags = SQLITE_DESERIALIZE_RESIZEABLE | SQLITE_DESERIALIZE_FREEONCLOSE;
+    p->szMax = sqlite3GlobalConfig.mxMemdbSize;
+  }
+  pFile->pStore = p;
+  if( pOutFlags!=0 ){
+    *pOutFlags = flags | SQLITE_OPEN_MEMORY;
+  }
+  pFd->pMethods = &memdb_io_methods;
+  memdbLeave(p);
+  return SQLITE_OK;
+}
+
+#if 0 /* Only used to delete rollback journals, super-journals, and WAL
+      ** files, none of which exist in memdb.  So this routine is never used */
+/*
+** Delete the file located at zPath. If the dirSync argument is true,
+** ensure the file-system modifications are synced to disk before
+** returning.
+*/
+static int memdbDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  return SQLITE_IOERR_DELETE;
+}
+#endif
+
+/*
+** Test for access permissions. Return true if the requested permission
+** is available, or false otherwise.
+**
+** With memdb, no files ever exist on disk.  So always return false.
+*/
+static int memdbAccess(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int flags,
+  int *pResOut
+){
+  UNUSED_PARAMETER(pVfs);
+  UNUSED_PARAMETER(zPath);
+  UNUSED_PARAMETER(flags);
+  *pResOut = 0;
+  return SQLITE_OK;
+}
+
+/*
+** Populate buffer zOut with the full canonical pathname corresponding
+** to the pathname in zPath. zOut is guaranteed to point to a buffer
+** of at least (INST_MAX_PATHNAME+1) bytes.
+*/
+static int memdbFullPathname(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int nOut,
+  char *zOut
+){
+  UNUSED_PARAMETER(pVfs);
+  sqlite3_snprintf(nOut, zOut, "%s", zPath);
+  return SQLITE_OK;
+}
+
+/*
+** Open the dynamic library located at zPath and return a handle.
+*/
+static void *memdbDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  return ORIGVFS(pVfs)->xDlOpen(ORIGVFS(pVfs), zPath);
+}
+
+/*
+** Populate the buffer zErrMsg (size nByte bytes) with a human readable
+** utf-8 string describing the most recent error encountered associated
+** with dynamic libraries.
+*/
+static void memdbDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
+  ORIGVFS(pVfs)->xDlError(ORIGVFS(pVfs), nByte, zErrMsg);
+}
+
+/*
+** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
+*/
+static void (*memdbDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
+  return ORIGVFS(pVfs)->xDlSym(ORIGVFS(pVfs), p, zSym);
+}
+
+/*
+** Close the dynamic library handle pHandle.
+*/
+static void memdbDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  ORIGVFS(pVfs)->xDlClose(ORIGVFS(pVfs), pHandle);
+}
+
+/*
+** Populate the buffer pointed to by zBufOut with nByte bytes of
+** random data.
+*/
+static int memdbRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  return ORIGVFS(pVfs)->xRandomness(ORIGVFS(pVfs), nByte, zBufOut);
+}
+
+/*
+** Sleep for nMicro microseconds. Return the number of microseconds
+** actually slept.
+*/
+static int memdbSleep(sqlite3_vfs *pVfs, int nMicro){
+  return ORIGVFS(pVfs)->xSleep(ORIGVFS(pVfs), nMicro);
+}
+
+#if 0  /* Never used.  Modern cores only call xCurrentTimeInt64() */
+/*
+** Return the current time as a Julian Day number in *pTimeOut.
+*/
+static int memdbCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+  return ORIGVFS(pVfs)->xCurrentTime(ORIGVFS(pVfs), pTimeOut);
+}
+#endif
+
+static int memdbGetLastError(sqlite3_vfs *pVfs, int a, char *b){
+  return ORIGVFS(pVfs)->xGetLastError(ORIGVFS(pVfs), a, b);
+}
+static int memdbCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *p){
+  return ORIGVFS(pVfs)->xCurrentTimeInt64(ORIGVFS(pVfs), p);
+}
+
+/*
+** Translate a database connection pointer and schema name into a
+** MemFile pointer.
+*/
+static MemFile *memdbFromDbSchema(sqlite3 *db, const char *zSchema){
+  MemFile *p = 0;
+  MemStore *pStore;
+  int rc = sqlite3_file_control(db, zSchema, SQLITE_FCNTL_FILE_POINTER, &p);
+  if( rc ) return 0;
+  if( p->base.pMethods!=&memdb_io_methods ) return 0;
+  pStore = p->pStore;
+  memdbEnter(pStore);
+  if( pStore->zFName!=0 ) p = 0;
+  memdbLeave(pStore);
+  return p;
+}
+
+/*
+** Return the serialization of a database
+*/
+SQLITE_API unsigned char *sqlite3_serialize(
+  sqlite3 *db,              /* The database connection */
+  const char *zSchema,      /* Which database within the connection */
+  sqlite3_int64 *piSize,    /* Write size here, if not NULL */
+  unsigned int mFlags       /* Maybe SQLITE_SERIALIZE_NOCOPY */
+){
+  MemFile *p;
+  int iDb;
+  Btree *pBt;
+  sqlite3_int64 sz;
+  int szPage = 0;
+  sqlite3_stmt *pStmt = 0;
+  unsigned char *pOut;
+  char *zSql;
+  int rc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+
+  if( zSchema==0 ) zSchema = db->aDb[0].zDbSName;
+  p = memdbFromDbSchema(db, zSchema);
+  iDb = sqlite3FindDbName(db, zSchema);
+  if( piSize ) *piSize = -1;
+  if( iDb<0 ) return 0;
+  if( p ){
+    MemStore *pStore = p->pStore;
+    assert( pStore->pMutex==0 );
+    if( piSize ) *piSize = pStore->sz;
+    if( mFlags & SQLITE_SERIALIZE_NOCOPY ){
+      pOut = pStore->aData;
+    }else{
+      pOut = sqlite3_malloc64( pStore->sz );
+      if( pOut ) memcpy(pOut, pStore->aData, pStore->sz);
+    }
+    return pOut;
+  }
+  pBt = db->aDb[iDb].pBt;
+  if( pBt==0 ) return 0;
+  szPage = sqlite3BtreeGetPageSize(pBt);
+  zSql = sqlite3_mprintf("PRAGMA \"%w\".page_count", zSchema);
+  rc = zSql ? sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0) : SQLITE_NOMEM;
+  sqlite3_free(zSql);
+  if( rc ) return 0;
+  rc = sqlite3_step(pStmt);
+  if( rc!=SQLITE_ROW ){
+    pOut = 0;
+  }else{
+    sz = sqlite3_column_int64(pStmt, 0)*szPage;
+    if( sz==0 ){
+      sqlite3_reset(pStmt);
+      sqlite3_exec(db, "BEGIN IMMEDIATE; COMMIT;", 0, 0, 0);
+      rc = sqlite3_step(pStmt);
+      if( rc==SQLITE_ROW ){
+        sz = sqlite3_column_int64(pStmt, 0)*szPage;
+      }
+    }
+    if( piSize ) *piSize = sz;
+    if( mFlags & SQLITE_SERIALIZE_NOCOPY ){
+      pOut = 0;
+    }else{
+      pOut = sqlite3_malloc64( sz );
+      if( pOut ){
+        int nPage = sqlite3_column_int(pStmt, 0);
+        Pager *pPager = sqlite3BtreePager(pBt);
+        int pgno;
+        for(pgno=1; pgno<=nPage; pgno++){
+          DbPage *pPage = 0;
+          unsigned char *pTo = pOut + szPage*(sqlite3_int64)(pgno-1);
+          rc = sqlite3PagerGet(pPager, pgno, (DbPage**)&pPage, 0);
+          if( rc==SQLITE_OK ){
+            memcpy(pTo, sqlite3PagerGetData(pPage), szPage);
+          }else{
+            memset(pTo, 0, szPage);
+          }
+          sqlite3PagerUnref(pPage);
+        }
+      }
+    }
+  }
+  sqlite3_finalize(pStmt);
+  return pOut;
+}
+
+/* Convert zSchema to a MemDB and initialize its content.
+*/
+SQLITE_API int sqlite3_deserialize(
+  sqlite3 *db,            /* The database connection */
+  const char *zSchema,    /* Which DB to reopen with the deserialization */
+  unsigned char *pData,   /* The serialized database content */
+  sqlite3_int64 szDb,     /* Number bytes in the deserialization */
+  sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
+  unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
+){
+  MemFile *p;
+  char *zSql;
+  sqlite3_stmt *pStmt = 0;
+  int rc;
+  int iDb;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  if( szDb<0 ) return SQLITE_MISUSE_BKPT;
+  if( szBuf<0 ) return SQLITE_MISUSE_BKPT;
+#endif
+
+  sqlite3_mutex_enter(db->mutex);
+  if( zSchema==0 ) zSchema = db->aDb[0].zDbSName;
+  iDb = sqlite3FindDbName(db, zSchema);
+  testcase( iDb==1 );
+  if( iDb<2 && iDb!=0 ){
+    rc = SQLITE_ERROR;
+    goto end_deserialize;
+  }
+  zSql = sqlite3_mprintf("ATTACH x AS %Q", zSchema);
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+    sqlite3_free(zSql);
+  }
+  if( rc ) goto end_deserialize;
+  db->init.iDb = (u8)iDb;
+  db->init.reopenMemdb = 1;
+  rc = sqlite3_step(pStmt);
+  db->init.reopenMemdb = 0;
+  if( rc!=SQLITE_DONE ){
+    rc = SQLITE_ERROR;
+    goto end_deserialize;
+  }
+  p = memdbFromDbSchema(db, zSchema);
+  if( p==0 ){
+    rc = SQLITE_ERROR;
+  }else{
+    MemStore *pStore = p->pStore;
+    pStore->aData = pData;
+    pData = 0;
+    pStore->sz = szDb;
+    pStore->szAlloc = szBuf;
+    pStore->szMax = szBuf;
+    if( pStore->szMax<sqlite3GlobalConfig.mxMemdbSize ){
+      pStore->szMax = sqlite3GlobalConfig.mxMemdbSize;
+    }
+    pStore->mFlags = mFlags;
+    rc = SQLITE_OK;
+  }
+
+end_deserialize:
+  sqlite3_finalize(pStmt);
+  if( pData && (mFlags & SQLITE_DESERIALIZE_FREEONCLOSE)!=0 ){
+    sqlite3_free(pData);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Return true if the VFS is the memvfs.
+*/
+SQLITE_PRIVATE int sqlite3IsMemdb(const sqlite3_vfs *pVfs){
+  return pVfs==&memdb_vfs;
+}
+
+/*
+** This routine is called when the extension is loaded.
+** Register the new VFS.
+*/
+SQLITE_PRIVATE int sqlite3MemdbInit(void){
+  sqlite3_vfs *pLower = sqlite3_vfs_find(0);
+  unsigned int sz;
+  if( NEVER(pLower==0) ) return SQLITE_ERROR;
+  sz = pLower->szOsFile;
+  memdb_vfs.pAppData = pLower;
+  /* The following conditional can only be true when compiled for
+  ** Windows x86 and SQLITE_MAX_MMAP_SIZE=0.  We always leave
+  ** it in, to be safe, but it is marked as NO_TEST since there
+  ** is no way to reach it under most builds. */
+  if( sz<sizeof(MemFile) ) sz = sizeof(MemFile); /*NO_TEST*/
+  memdb_vfs.szOsFile = sz;
+  return sqlite3_vfs_register(&memdb_vfs, 0);
+}
+#endif /* SQLITE_OMIT_DESERIALIZE */
+
+/************** End of memdb.c ***********************************************/
+/************** Begin file bitvec.c ******************************************/
+/*
+** 2008 February 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements an object that represents a fixed-length
+** bitmap.  Bits are numbered starting with 1.
+**
+** A bitmap is used to record which pages of a database file have been
+** journalled during a transaction, or which pages have the "dont-write"
+** property.  Usually only a few pages are meet either condition.
+** So the bitmap is usually sparse and has low cardinality.
+** But sometimes (for example when during a DROP of a large table) most
+** or all of the pages in a database can get journalled.  In those cases,
+** the bitmap becomes dense with high cardinality.  The algorithm needs
+** to handle both cases well.
+**
+** The size of the bitmap is fixed when the object is created.
+**
+** All bits are clear when the bitmap is created.  Individual bits
+** may be set or cleared one at a time.
+**
+** Test operations are about 100 times more common that set operations.
+** Clear operations are exceedingly rare.  There are usually between
+** 5 and 500 set operations per Bitvec object, though the number of sets can
+** sometimes grow into tens of thousands or larger.  The size of the
+** Bitvec object is the number of pages in the database file at the
+** start of a transaction, and is thus usually less than a few thousand,
+** but can be as large as 2 billion for a really big database.
+*/
+/* #include "sqliteInt.h" */
+
+/* Size of the Bitvec structure in bytes. */
+#define BITVEC_SZ        512
+
+/* Round the union size down to the nearest pointer boundary, since that's how
+** it will be aligned within the Bitvec struct. */
+#define BITVEC_USIZE \
+    (((BITVEC_SZ-(3*sizeof(u32)))/sizeof(Bitvec*))*sizeof(Bitvec*))
+
+/* Type of the array "element" for the bitmap representation.
+** Should be a power of 2, and ideally, evenly divide into BITVEC_USIZE.
+** Setting this to the "natural word" size of your CPU may improve
+** performance. */
+#define BITVEC_TELEM     u8
+/* Size, in bits, of the bitmap element. */
+#define BITVEC_SZELEM    8
+/* Number of elements in a bitmap array. */
+#define BITVEC_NELEM     (BITVEC_USIZE/sizeof(BITVEC_TELEM))
+/* Number of bits in the bitmap array. */
+#define BITVEC_NBIT      (BITVEC_NELEM*BITVEC_SZELEM)
+
+/* Number of u32 values in hash table. */
+#define BITVEC_NINT      (BITVEC_USIZE/sizeof(u32))
+/* Maximum number of entries in hash table before
+** sub-dividing and re-hashing. */
+#define BITVEC_MXHASH    (BITVEC_NINT/2)
+/* Hashing function for the aHash representation.
+** Empirical testing showed that the *37 multiplier
+** (an arbitrary prime)in the hash function provided
+** no fewer collisions than the no-op *1. */
+#define BITVEC_HASH(X)   (((X)*1)%BITVEC_NINT)
+
+#define BITVEC_NPTR      (BITVEC_USIZE/sizeof(Bitvec *))
+
+
+/*
+** A bitmap is an instance of the following structure.
+**
+** This bitmap records the existence of zero or more bits
+** with values between 1 and iSize, inclusive.
+**
+** There are three possible representations of the bitmap.
+** If iSize<=BITVEC_NBIT, then Bitvec.u.aBitmap[] is a straight
+** bitmap.  The least significant bit is bit 1.
+**
+** If iSize>BITVEC_NBIT and iDivisor==0 then Bitvec.u.aHash[] is
+** a hash table that will hold up to BITVEC_MXHASH distinct values.
+**
+** Otherwise, the value i is redirected into one of BITVEC_NPTR
+** sub-bitmaps pointed to by Bitvec.u.apSub[].  Each subbitmap
+** handles up to iDivisor separate values of i.  apSub[0] holds
+** values between 1 and iDivisor.  apSub[1] holds values between
+** iDivisor+1 and 2*iDivisor.  apSub[N] holds values between
+** N*iDivisor+1 and (N+1)*iDivisor.  Each subbitmap is normalized
+** to hold deal with values between 1 and iDivisor.
+*/
+struct Bitvec {
+  u32 iSize;      /* Maximum bit index.  Max iSize is 4,294,967,296. */
+  u32 nSet;       /* Number of bits that are set - only valid for aHash
+                  ** element.  Max is BITVEC_NINT.  For BITVEC_SZ of 512,
+                  ** this would be 125. */
+  u32 iDivisor;   /* Number of bits handled by each apSub[] entry. */
+                  /* Should >=0 for apSub element. */
+                  /* Max iDivisor is max(u32) / BITVEC_NPTR + 1.  */
+                  /* For a BITVEC_SZ of 512, this would be 34,359,739. */
+  union {
+    BITVEC_TELEM aBitmap[BITVEC_NELEM];    /* Bitmap representation */
+    u32 aHash[BITVEC_NINT];      /* Hash table representation */
+    Bitvec *apSub[BITVEC_NPTR];  /* Recursive representation */
+  } u;
+};
+
+/*
+** Create a new bitmap object able to handle bits between 0 and iSize,
+** inclusive.  Return a pointer to the new object.  Return NULL if
+** malloc fails.
+*/
+SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32 iSize){
+  Bitvec *p;
+  assert( sizeof(*p)==BITVEC_SZ );
+  p = sqlite3MallocZero( sizeof(*p) );
+  if( p ){
+    p->iSize = iSize;
+  }
+  return p;
+}
+
+/*
+** Check to see if the i-th bit is set.  Return true or false.
+** If p is NULL (if the bitmap has not been created) or if
+** i is out of range, then return false.
+*/
+SQLITE_PRIVATE int sqlite3BitvecTestNotNull(Bitvec *p, u32 i){
+  assert( p!=0 );
+  i--;
+  if( i>=p->iSize ) return 0;
+  while( p->iDivisor ){
+    u32 bin = i/p->iDivisor;
+    i = i%p->iDivisor;
+    p = p->u.apSub[bin];
+    if (!p) {
+      return 0;
+    }
+  }
+  if( p->iSize<=BITVEC_NBIT ){
+    return (p->u.aBitmap[i/BITVEC_SZELEM] & (1<<(i&(BITVEC_SZELEM-1))))!=0;
+  } else{
+    u32 h = BITVEC_HASH(i++);
+    while( p->u.aHash[h] ){
+      if( p->u.aHash[h]==i ) return 1;
+      h = (h+1) % BITVEC_NINT;
+    }
+    return 0;
+  }
+}
+SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec *p, u32 i){
+  return p!=0 && sqlite3BitvecTestNotNull(p,i);
+}
+
+/*
+** Set the i-th bit.  Return 0 on success and an error code if
+** anything goes wrong.
+**
+** This routine might cause sub-bitmaps to be allocated.  Failing
+** to get the memory needed to hold the sub-bitmap is the only
+** that can go wrong with an insert, assuming p and i are valid.
+**
+** The calling function must ensure that p is a valid Bitvec object
+** and that the value for "i" is within range of the Bitvec object.
+** Otherwise the behavior is undefined.
+*/
+SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec *p, u32 i){
+  u32 h;
+  if( p==0 ) return SQLITE_OK;
+  assert( i>0 );
+  assert( i<=p->iSize );
+  i--;
+  while((p->iSize > BITVEC_NBIT) && p->iDivisor) {
+    u32 bin = i/p->iDivisor;
+    i = i%p->iDivisor;
+    if( p->u.apSub[bin]==0 ){
+      p->u.apSub[bin] = sqlite3BitvecCreate( p->iDivisor );
+      if( p->u.apSub[bin]==0 ) return SQLITE_NOMEM_BKPT;
+    }
+    p = p->u.apSub[bin];
+  }
+  if( p->iSize<=BITVEC_NBIT ){
+    p->u.aBitmap[i/BITVEC_SZELEM] |= 1 << (i&(BITVEC_SZELEM-1));
+    return SQLITE_OK;
+  }
+  h = BITVEC_HASH(i++);
+  /* if there wasn't a hash collision, and this doesn't */
+  /* completely fill the hash, then just add it without */
+  /* worrying about sub-dividing and re-hashing. */
+  if( !p->u.aHash[h] ){
+    if (p->nSet<(BITVEC_NINT-1)) {
+      goto bitvec_set_end;
+    } else {
+      goto bitvec_set_rehash;
+    }
+  }
+  /* there was a collision, check to see if it's already */
+  /* in hash, if not, try to find a spot for it */
+  do {
+    if( p->u.aHash[h]==i ) return SQLITE_OK;
+    h++;
+    if( h>=BITVEC_NINT ) h = 0;
+  } while( p->u.aHash[h] );
+  /* we didn't find it in the hash.  h points to the first */
+  /* available free spot. check to see if this is going to */
+  /* make our hash too "full".  */
+bitvec_set_rehash:
+  if( p->nSet>=BITVEC_MXHASH ){
+    unsigned int j;
+    int rc;
+    u32 *aiValues = sqlite3StackAllocRaw(0, sizeof(p->u.aHash));
+    if( aiValues==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }else{
+      memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
+      memset(p->u.apSub, 0, sizeof(p->u.apSub));
+      p->iDivisor = (p->iSize + BITVEC_NPTR - 1)/BITVEC_NPTR;
+      rc = sqlite3BitvecSet(p, i);
+      for(j=0; j<BITVEC_NINT; j++){
+        if( aiValues[j] ) rc |= sqlite3BitvecSet(p, aiValues[j]);
+      }
+      sqlite3StackFree(0, aiValues);
+      return rc;
+    }
+  }
+bitvec_set_end:
+  p->nSet++;
+  p->u.aHash[h] = i;
+  return SQLITE_OK;
+}
+
+/*
+** Clear the i-th bit.
+**
+** pBuf must be a pointer to at least BITVEC_SZ bytes of temporary storage
+** that BitvecClear can use to rebuilt its hash table.
+*/
+SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec *p, u32 i, void *pBuf){
+  if( p==0 ) return;
+  assert( i>0 );
+  i--;
+  while( p->iDivisor ){
+    u32 bin = i/p->iDivisor;
+    i = i%p->iDivisor;
+    p = p->u.apSub[bin];
+    if (!p) {
+      return;
+    }
+  }
+  if( p->iSize<=BITVEC_NBIT ){
+    p->u.aBitmap[i/BITVEC_SZELEM] &= ~(1 << (i&(BITVEC_SZELEM-1)));
+  }else{
+    unsigned int j;
+    u32 *aiValues = pBuf;
+    memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
+    memset(p->u.aHash, 0, sizeof(p->u.aHash));
+    p->nSet = 0;
+    for(j=0; j<BITVEC_NINT; j++){
+      if( aiValues[j] && aiValues[j]!=(i+1) ){
+        u32 h = BITVEC_HASH(aiValues[j]-1);
+        p->nSet++;
+        while( p->u.aHash[h] ){
+          h++;
+          if( h>=BITVEC_NINT ) h = 0;
+        }
+        p->u.aHash[h] = aiValues[j];
+      }
+    }
+  }
+}
+
+/*
+** Destroy a bitmap object.  Reclaim all memory used.
+*/
+SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec *p){
+  if( p==0 ) return;
+  if( p->iDivisor ){
+    unsigned int i;
+    for(i=0; i<BITVEC_NPTR; i++){
+      sqlite3BitvecDestroy(p->u.apSub[i]);
+    }
+  }
+  sqlite3_free(p);
+}
+
+/*
+** Return the value of the iSize parameter specified when Bitvec *p
+** was created.
+*/
+SQLITE_PRIVATE u32 sqlite3BitvecSize(Bitvec *p){
+  return p->iSize;
+}
+
+#ifndef SQLITE_UNTESTABLE
+/*
+** Let V[] be an array of unsigned characters sufficient to hold
+** up to N bits.  Let I be an integer between 0 and N.  0<=I<N.
+** Then the following macros can be used to set, clear, or test
+** individual bits within V.
+*/
+#define SETBIT(V,I)      V[I>>3] |= (1<<(I&7))
+#define CLEARBIT(V,I)    V[I>>3] &= ~(1<<(I&7))
+#define TESTBIT(V,I)     (V[I>>3]&(1<<(I&7)))!=0
+
+/*
+** This routine runs an extensive test of the Bitvec code.
+**
+** The input is an array of integers that acts as a program
+** to test the Bitvec.  The integers are opcodes followed
+** by 0, 1, or 3 operands, depending on the opcode.  Another
+** opcode follows immediately after the last operand.
+**
+** There are 6 opcodes numbered from 0 through 5.  0 is the
+** "halt" opcode and causes the test to end.
+**
+**    0          Halt and return the number of errors
+**    1 N S X    Set N bits beginning with S and incrementing by X
+**    2 N S X    Clear N bits beginning with S and incrementing by X
+**    3 N        Set N randomly chosen bits
+**    4 N        Clear N randomly chosen bits
+**    5 N S X    Set N bits from S increment X in array only, not in bitvec
+**
+** The opcodes 1 through 4 perform set and clear operations are performed
+** on both a Bitvec object and on a linear array of bits obtained from malloc.
+** Opcode 5 works on the linear array only, not on the Bitvec.
+** Opcode 5 is used to deliberately induce a fault in order to
+** confirm that error detection works.
+**
+** At the conclusion of the test the linear array is compared
+** against the Bitvec object.  If there are any differences,
+** an error is returned.  If they are the same, zero is returned.
+**
+** If a memory allocation error occurs, return -1.
+*/
+SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int sz, int *aOp){
+  Bitvec *pBitvec = 0;
+  unsigned char *pV = 0;
+  int rc = -1;
+  int i, nx, pc, op;
+  void *pTmpSpace;
+
+  /* Allocate the Bitvec to be tested and a linear array of
+  ** bits to act as the reference */
+  pBitvec = sqlite3BitvecCreate( sz );
+  pV = sqlite3MallocZero( (sz+7)/8 + 1 );
+  pTmpSpace = sqlite3_malloc64(BITVEC_SZ);
+  if( pBitvec==0 || pV==0 || pTmpSpace==0  ) goto bitvec_end;
+
+  /* NULL pBitvec tests */
+  sqlite3BitvecSet(0, 1);
+  sqlite3BitvecClear(0, 1, pTmpSpace);
+
+  /* Run the program */
+  pc = i = 0;
+  while( (op = aOp[pc])!=0 ){
+    switch( op ){
+      case 1:
+      case 2:
+      case 5: {
+        nx = 4;
+        i = aOp[pc+2] - 1;
+        aOp[pc+2] += aOp[pc+3];
+        break;
+      }
+      case 3:
+      case 4:
+      default: {
+        nx = 2;
+        sqlite3_randomness(sizeof(i), &i);
+        break;
+      }
+    }
+    if( (--aOp[pc+1]) > 0 ) nx = 0;
+    pc += nx;
+    i = (i & 0x7fffffff)%sz;
+    if( (op & 1)!=0 ){
+      SETBIT(pV, (i+1));
+      if( op!=5 ){
+        if( sqlite3BitvecSet(pBitvec, i+1) ) goto bitvec_end;
+      }
+    }else{
+      CLEARBIT(pV, (i+1));
+      sqlite3BitvecClear(pBitvec, i+1, pTmpSpace);
+    }
+  }
+
+  /* Test to make sure the linear array exactly matches the
+  ** Bitvec object.  Start with the assumption that they do
+  ** match (rc==0).  Change rc to non-zero if a discrepancy
+  ** is found.
+  */
+  rc = sqlite3BitvecTest(0,0) + sqlite3BitvecTest(pBitvec, sz+1)
+          + sqlite3BitvecTest(pBitvec, 0)
+          + (sqlite3BitvecSize(pBitvec) - sz);
+  for(i=1; i<=sz; i++){
+    if(  (TESTBIT(pV,i))!=sqlite3BitvecTest(pBitvec,i) ){
+      rc = i;
+      break;
+    }
+  }
+
+  /* Free allocated structure */
+bitvec_end:
+  sqlite3_free(pTmpSpace);
+  sqlite3_free(pV);
+  sqlite3BitvecDestroy(pBitvec);
+  return rc;
+}
+#endif /* SQLITE_UNTESTABLE */
+
+/************** End of bitvec.c **********************************************/
+/************** Begin file pcache.c ******************************************/
+/*
+** 2008 August 05
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements that page cache.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** A complete page cache is an instance of this structure.  Every
+** entry in the cache holds a single page of the database file.  The
+** btree layer only operates on the cached copy of the database pages.
+**
+** A page cache entry is "clean" if it exactly matches what is currently
+** on disk.  A page is "dirty" if it has been modified and needs to be
+** persisted to disk.
+**
+** pDirty, pDirtyTail, pSynced:
+**   All dirty pages are linked into the doubly linked list using
+**   PgHdr.pDirtyNext and pDirtyPrev. The list is maintained in LRU order
+**   such that p was added to the list more recently than p->pDirtyNext.
+**   PCache.pDirty points to the first (newest) element in the list and
+**   pDirtyTail to the last (oldest).
+**
+**   The PCache.pSynced variable is used to optimize searching for a dirty
+**   page to eject from the cache mid-transaction. It is better to eject
+**   a page that does not require a journal sync than one that does.
+**   Therefore, pSynced is maintained so that it *almost* always points
+**   to either the oldest page in the pDirty/pDirtyTail list that has a
+**   clear PGHDR_NEED_SYNC flag or to a page that is older than this one
+**   (so that the right page to eject can be found by following pDirtyPrev
+**   pointers).
+*/
+struct PCache {
+  PgHdr *pDirty, *pDirtyTail;         /* List of dirty pages in LRU order */
+  PgHdr *pSynced;                     /* Last synced page in dirty page list */
+  i64 nRefSum;                        /* Sum of ref counts over all pages */
+  int szCache;                        /* Configured cache size */
+  int szSpill;                        /* Size before spilling occurs */
+  int szPage;                         /* Size of every page in this cache */
+  int szExtra;                        /* Size of extra space for each page */
+  u8 bPurgeable;                      /* True if pages are on backing store */
+  u8 eCreate;                         /* eCreate value for for xFetch() */
+  int (*xStress)(void*,PgHdr*);       /* Call to try make a page clean */
+  void *pStress;                      /* Argument to xStress */
+  sqlite3_pcache *pCache;             /* Pluggable cache module */
+};
+
+/********************************** Test and Debug Logic **********************/
+/*
+** Debug tracing macros.  Enable by by changing the "0" to "1" and
+** recompiling.
+**
+** When sqlite3PcacheTrace is 1, single line trace messages are issued.
+** When sqlite3PcacheTrace is 2, a dump of the pcache showing all cache entries
+** is displayed for many operations, resulting in a lot of output.
+*/
+#if defined(SQLITE_DEBUG) && 0
+  int sqlite3PcacheTrace = 2;       /* 0: off  1: simple  2: cache dumps */
+  int sqlite3PcacheMxDump = 9999;   /* Max cache entries for pcacheDump() */
+# define pcacheTrace(X) if(sqlite3PcacheTrace){sqlite3DebugPrintf X;}
+  static void pcachePageTrace(int i, sqlite3_pcache_page *pLower){
+    PgHdr *pPg;
+    unsigned char *a;
+    int j;
+    if( pLower==0 ){
+      printf("%3d: NULL\n", i);
+    }else{
+      pPg = (PgHdr*)pLower->pExtra;
+      printf("%3d: nRef %2lld flgs %02x data ", i, pPg->nRef, pPg->flags);
+      a = (unsigned char *)pLower->pBuf;
+      for(j=0; j<12; j++) printf("%02x", a[j]);
+      printf(" ptr %p\n", pPg);
+    }
+  }
+  static void pcacheDump(PCache *pCache){
+    int N;
+    int i;
+    sqlite3_pcache_page *pLower;
+
+    if( sqlite3PcacheTrace<2 ) return;
+    if( pCache->pCache==0 ) return;
+    N = sqlite3PcachePagecount(pCache);
+    if( N>sqlite3PcacheMxDump ) N = sqlite3PcacheMxDump;
+    for(i=1; i<=N; i++){
+       pLower = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, i, 0);
+       pcachePageTrace(i, pLower);
+       if( pLower && ((PgHdr*)pLower)->pPage==0 ){
+         sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, pLower, 0);
+       }
+    }
+  }
+#else
+# define pcacheTrace(X)
+# define pcachePageTrace(PGNO, X)
+# define pcacheDump(X)
+#endif
+
+/*
+** Return 1 if pPg is on the dirty list for pCache.  Return 0 if not.
+** This routine runs inside of assert() statements only.
+*/
+#if defined(SQLITE_ENABLE_EXPENSIVE_ASSERT)
+static int pageOnDirtyList(PCache *pCache, PgHdr *pPg){
+  PgHdr *p;
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    if( p==pPg ) return 1;
+  }
+  return 0;
+}
+static int pageNotOnDirtyList(PCache *pCache, PgHdr *pPg){
+  PgHdr *p;
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    if( p==pPg ) return 0;
+  }
+  return 1;
+}
+#else
+# define pageOnDirtyList(A,B)    1
+# define pageNotOnDirtyList(A,B) 1
+#endif
+
+/*
+** Check invariants on a PgHdr entry.  Return true if everything is OK.
+** Return false if any invariant is violated.
+**
+** This routine is for use inside of assert() statements only.  For
+** example:
+**
+**          assert( sqlite3PcachePageSanity(pPg) );
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3PcachePageSanity(PgHdr *pPg){
+  PCache *pCache;
+  assert( pPg!=0 );
+  assert( pPg->pgno>0 || pPg->pPager==0 );    /* Page number is 1 or more */
+  pCache = pPg->pCache;
+  assert( pCache!=0 );      /* Every page has an associated PCache */
+  if( pPg->flags & PGHDR_CLEAN ){
+    assert( (pPg->flags & PGHDR_DIRTY)==0 );/* Cannot be both CLEAN and DIRTY */
+    assert( pageNotOnDirtyList(pCache, pPg) );/* CLEAN pages not on dirtylist */
+  }else{
+    assert( (pPg->flags & PGHDR_DIRTY)!=0 );/* If not CLEAN must be DIRTY */
+    assert( pPg->pDirtyNext==0 || pPg->pDirtyNext->pDirtyPrev==pPg );
+    assert( pPg->pDirtyPrev==0 || pPg->pDirtyPrev->pDirtyNext==pPg );
+    assert( pPg->pDirtyPrev!=0 || pCache->pDirty==pPg );
+    assert( pageOnDirtyList(pCache, pPg) );
+  }
+  /* WRITEABLE pages must also be DIRTY */
+  if( pPg->flags & PGHDR_WRITEABLE ){
+    assert( pPg->flags & PGHDR_DIRTY );     /* WRITEABLE implies DIRTY */
+  }
+  /* NEED_SYNC can be set independently of WRITEABLE.  This can happen,
+  ** for example, when using the sqlite3PagerDontWrite() optimization:
+  **    (1)  Page X is journalled, and gets WRITEABLE and NEED_SEEK.
+  **    (2)  Page X moved to freelist, WRITEABLE is cleared
+  **    (3)  Page X reused, WRITEABLE is set again
+  ** If NEED_SYNC had been cleared in step 2, then it would not be reset
+  ** in step 3, and page might be written into the database without first
+  ** syncing the rollback journal, which might cause corruption on a power
+  ** loss.
+  **
+  ** Another example is when the database page size is smaller than the
+  ** disk sector size.  When any page of a sector is journalled, all pages
+  ** in that sector are marked NEED_SYNC even if they are still CLEAN, just
+  ** in case they are later modified, since all pages in the same sector
+  ** must be journalled and synced before any of those pages can be safely
+  ** written.
+  */
+  return 1;
+}
+#endif /* SQLITE_DEBUG */
+
+
+/********************************** Linked List Management ********************/
+
+/* Allowed values for second argument to pcacheManageDirtyList() */
+#define PCACHE_DIRTYLIST_REMOVE   1    /* Remove pPage from dirty list */
+#define PCACHE_DIRTYLIST_ADD      2    /* Add pPage to the dirty list */
+#define PCACHE_DIRTYLIST_FRONT    3    /* Move pPage to the front of the list */
+
+/*
+** Manage pPage's participation on the dirty list.  Bits of the addRemove
+** argument determines what operation to do.  The 0x01 bit means first
+** remove pPage from the dirty list.  The 0x02 means add pPage back to
+** the dirty list.  Doing both moves pPage to the front of the dirty list.
+*/
+static void pcacheManageDirtyList(PgHdr *pPage, u8 addRemove){
+  PCache *p = pPage->pCache;
+
+  pcacheTrace(("%p.DIRTYLIST.%s %d\n", p,
+                addRemove==1 ? "REMOVE" : addRemove==2 ? "ADD" : "FRONT",
+                pPage->pgno));
+  if( addRemove & PCACHE_DIRTYLIST_REMOVE ){
+    assert( pPage->pDirtyNext || pPage==p->pDirtyTail );
+    assert( pPage->pDirtyPrev || pPage==p->pDirty );
+
+    /* Update the PCache1.pSynced variable if necessary. */
+    if( p->pSynced==pPage ){
+      p->pSynced = pPage->pDirtyPrev;
+    }
+
+    if( pPage->pDirtyNext ){
+      pPage->pDirtyNext->pDirtyPrev = pPage->pDirtyPrev;
+    }else{
+      assert( pPage==p->pDirtyTail );
+      p->pDirtyTail = pPage->pDirtyPrev;
+    }
+    if( pPage->pDirtyPrev ){
+      pPage->pDirtyPrev->pDirtyNext = pPage->pDirtyNext;
+    }else{
+      /* If there are now no dirty pages in the cache, set eCreate to 2.
+      ** This is an optimization that allows sqlite3PcacheFetch() to skip
+      ** searching for a dirty page to eject from the cache when it might
+      ** otherwise have to.  */
+      assert( pPage==p->pDirty );
+      p->pDirty = pPage->pDirtyNext;
+      assert( p->bPurgeable || p->eCreate==2 );
+      if( p->pDirty==0 ){         /*OPTIMIZATION-IF-TRUE*/
+        assert( p->bPurgeable==0 || p->eCreate==1 );
+        p->eCreate = 2;
+      }
+    }
+  }
+  if( addRemove & PCACHE_DIRTYLIST_ADD ){
+    pPage->pDirtyPrev = 0;
+    pPage->pDirtyNext = p->pDirty;
+    if( pPage->pDirtyNext ){
+      assert( pPage->pDirtyNext->pDirtyPrev==0 );
+      pPage->pDirtyNext->pDirtyPrev = pPage;
+    }else{
+      p->pDirtyTail = pPage;
+      if( p->bPurgeable ){
+        assert( p->eCreate==2 );
+        p->eCreate = 1;
+      }
+    }
+    p->pDirty = pPage;
+
+    /* If pSynced is NULL and this page has a clear NEED_SYNC flag, set
+    ** pSynced to point to it. Checking the NEED_SYNC flag is an
+    ** optimization, as if pSynced points to a page with the NEED_SYNC
+    ** flag set sqlite3PcacheFetchStress() searches through all newer
+    ** entries of the dirty-list for a page with NEED_SYNC clear anyway.  */
+    if( !p->pSynced
+     && 0==(pPage->flags&PGHDR_NEED_SYNC)   /*OPTIMIZATION-IF-FALSE*/
+    ){
+      p->pSynced = pPage;
+    }
+  }
+  pcacheDump(p);
+}
+
+/*
+** Wrapper around the pluggable caches xUnpin method. If the cache is
+** being used for an in-memory database, this function is a no-op.
+*/
+static void pcacheUnpin(PgHdr *p){
+  if( p->pCache->bPurgeable ){
+    pcacheTrace(("%p.UNPIN %d\n", p->pCache, p->pgno));
+    sqlite3GlobalConfig.pcache2.xUnpin(p->pCache->pCache, p->pPage, 0);
+    pcacheDump(p->pCache);
+  }
+}
+
+/*
+** Compute the number of pages of cache requested.   p->szCache is the
+** cache size requested by the "PRAGMA cache_size" statement.
+*/
+static int numberOfCachePages(PCache *p){
+  if( p->szCache>=0 ){
+    /* IMPLEMENTATION-OF: R-42059-47211 If the argument N is positive then the
+    ** suggested cache size is set to N. */
+    return p->szCache;
+  }else{
+    i64 n;
+    /* IMPLEMENTATION-OF: R-59858-46238 If the argument N is negative, then the
+    ** number of cache pages is adjusted to be a number of pages that would
+    ** use approximately abs(N*1024) bytes of memory based on the current
+    ** page size. */
+    n = ((-1024*(i64)p->szCache)/(p->szPage+p->szExtra));
+    if( n>1000000000 ) n = 1000000000;
+    return (int)n;
+  }
+}
+
+/*************************************************** General Interfaces ******
+**
+** Initialize and shutdown the page cache subsystem. Neither of these
+** functions are threadsafe.
+*/
+SQLITE_PRIVATE int sqlite3PcacheInitialize(void){
+  if( sqlite3GlobalConfig.pcache2.xInit==0 ){
+    /* IMPLEMENTATION-OF: R-26801-64137 If the xInit() method is NULL, then the
+    ** built-in default page cache is used instead of the application defined
+    ** page cache. */
+    sqlite3PCacheSetDefault();
+    assert( sqlite3GlobalConfig.pcache2.xInit!=0 );
+  }
+  return sqlite3GlobalConfig.pcache2.xInit(sqlite3GlobalConfig.pcache2.pArg);
+}
+SQLITE_PRIVATE void sqlite3PcacheShutdown(void){
+  if( sqlite3GlobalConfig.pcache2.xShutdown ){
+    /* IMPLEMENTATION-OF: R-26000-56589 The xShutdown() method may be NULL. */
+    sqlite3GlobalConfig.pcache2.xShutdown(sqlite3GlobalConfig.pcache2.pArg);
+  }
+}
+
+/*
+** Return the size in bytes of a PCache object.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSize(void){ return sizeof(PCache); }
+
+/*
+** Create a new PCache object. Storage space to hold the object
+** has already been allocated and is passed in as the p pointer.
+** The caller discovers how much space needs to be allocated by
+** calling sqlite3PcacheSize().
+**
+** szExtra is some extra space allocated for each page.  The first
+** 8 bytes of the extra space will be zeroed as the page is allocated,
+** but remaining content will be uninitialized.  Though it is opaque
+** to this module, the extra space really ends up being the MemPage
+** structure in the pager.
+*/
+SQLITE_PRIVATE int sqlite3PcacheOpen(
+  int szPage,                  /* Size of every page */
+  int szExtra,                 /* Extra space associated with each page */
+  int bPurgeable,              /* True if pages are on backing store */
+  int (*xStress)(void*,PgHdr*),/* Call to try to make pages clean */
+  void *pStress,               /* Argument to xStress */
+  PCache *p                    /* Preallocated space for the PCache */
+){
+  memset(p, 0, sizeof(PCache));
+  p->szPage = 1;
+  p->szExtra = szExtra;
+  assert( szExtra>=8 );  /* First 8 bytes will be zeroed */
+  p->bPurgeable = bPurgeable;
+  p->eCreate = 2;
+  p->xStress = xStress;
+  p->pStress = pStress;
+  p->szCache = 100;
+  p->szSpill = 1;
+  pcacheTrace(("%p.OPEN szPage %d bPurgeable %d\n",p,szPage,bPurgeable));
+  return sqlite3PcacheSetPageSize(p, szPage);
+}
+
+/*
+** Change the page size for PCache object. The caller must ensure that there
+** are no outstanding page references when this function is called.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSetPageSize(PCache *pCache, int szPage){
+  assert( pCache->nRefSum==0 && pCache->pDirty==0 );
+  if( pCache->szPage ){
+    sqlite3_pcache *pNew;
+    pNew = sqlite3GlobalConfig.pcache2.xCreate(
+                szPage, pCache->szExtra + ROUND8(sizeof(PgHdr)),
+                pCache->bPurgeable
+    );
+    if( pNew==0 ) return SQLITE_NOMEM_BKPT;
+    sqlite3GlobalConfig.pcache2.xCachesize(pNew, numberOfCachePages(pCache));
+    if( pCache->pCache ){
+      sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
+    }
+    pCache->pCache = pNew;
+    pCache->szPage = szPage;
+    pcacheTrace(("%p.PAGESIZE %d\n",pCache,szPage));
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Try to obtain a page from the cache.
+**
+** This routine returns a pointer to an sqlite3_pcache_page object if
+** such an object is already in cache, or if a new one is created.
+** This routine returns a NULL pointer if the object was not in cache
+** and could not be created.
+**
+** The createFlags should be 0 to check for existing pages and should
+** be 3 (not 1, but 3) to try to create a new page.
+**
+** If the createFlag is 0, then NULL is always returned if the page
+** is not already in the cache.  If createFlag is 1, then a new page
+** is created only if that can be done without spilling dirty pages
+** and without exceeding the cache size limit.
+**
+** The caller needs to invoke sqlite3PcacheFetchFinish() to properly
+** initialize the sqlite3_pcache_page object and convert it into a
+** PgHdr object.  The sqlite3PcacheFetch() and sqlite3PcacheFetchFinish()
+** routines are split this way for performance reasons. When separated
+** they can both (usually) operate without having to push values to
+** the stack on entry and pop them back off on exit, which saves a
+** lot of pushing and popping.
+*/
+SQLITE_PRIVATE sqlite3_pcache_page *sqlite3PcacheFetch(
+  PCache *pCache,       /* Obtain the page from this cache */
+  Pgno pgno,            /* Page number to obtain */
+  int createFlag        /* If true, create page if it does not exist already */
+){
+  int eCreate;
+  sqlite3_pcache_page *pRes;
+
+  assert( pCache!=0 );
+  assert( pCache->pCache!=0 );
+  assert( createFlag==3 || createFlag==0 );
+  assert( pCache->eCreate==((pCache->bPurgeable && pCache->pDirty) ? 1 : 2) );
+
+  /* eCreate defines what to do if the page does not exist.
+  **    0     Do not allocate a new page.  (createFlag==0)
+  **    1     Allocate a new page if doing so is inexpensive.
+  **          (createFlag==1 AND bPurgeable AND pDirty)
+  **    2     Allocate a new page even it doing so is difficult.
+  **          (createFlag==1 AND !(bPurgeable AND pDirty)
+  */
+  eCreate = createFlag & pCache->eCreate;
+  assert( eCreate==0 || eCreate==1 || eCreate==2 );
+  assert( createFlag==0 || pCache->eCreate==eCreate );
+  assert( createFlag==0 || eCreate==1+(!pCache->bPurgeable||!pCache->pDirty) );
+  pRes = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
+  pcacheTrace(("%p.FETCH %d%s (result: %p) ",pCache,pgno,
+               createFlag?" create":"",pRes));
+  pcachePageTrace(pgno, pRes);
+  return pRes;
+}
+
+/*
+** If the sqlite3PcacheFetch() routine is unable to allocate a new
+** page because no clean pages are available for reuse and the cache
+** size limit has been reached, then this routine can be invoked to
+** try harder to allocate a page.  This routine might invoke the stress
+** callback to spill dirty pages to the journal.  It will then try to
+** allocate the new page and will only fail to allocate a new page on
+** an OOM error.
+**
+** This routine should be invoked only after sqlite3PcacheFetch() fails.
+*/
+SQLITE_PRIVATE int sqlite3PcacheFetchStress(
+  PCache *pCache,                 /* Obtain the page from this cache */
+  Pgno pgno,                      /* Page number to obtain */
+  sqlite3_pcache_page **ppPage    /* Write result here */
+){
+  PgHdr *pPg;
+  if( pCache->eCreate==2 ) return 0;
+
+  if( sqlite3PcachePagecount(pCache)>pCache->szSpill ){
+    /* Find a dirty page to write-out and recycle. First try to find a
+    ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC
+    ** cleared), but if that is not possible settle for any other
+    ** unreferenced dirty page.
+    **
+    ** If the LRU page in the dirty list that has a clear PGHDR_NEED_SYNC
+    ** flag is currently referenced, then the following may leave pSynced
+    ** set incorrectly (pointing to other than the LRU page with NEED_SYNC
+    ** cleared). This is Ok, as pSynced is just an optimization.  */
+    for(pPg=pCache->pSynced;
+        pPg && (pPg->nRef || (pPg->flags&PGHDR_NEED_SYNC));
+        pPg=pPg->pDirtyPrev
+    );
+    pCache->pSynced = pPg;
+    if( !pPg ){
+      for(pPg=pCache->pDirtyTail; pPg && pPg->nRef; pPg=pPg->pDirtyPrev);
+    }
+    if( pPg ){
+      int rc;
+#ifdef SQLITE_LOG_CACHE_SPILL
+      sqlite3_log(SQLITE_FULL,
+                  "spill page %d making room for %d - cache used: %d/%d",
+                  pPg->pgno, pgno,
+                  sqlite3GlobalConfig.pcache2.xPagecount(pCache->pCache),
+                numberOfCachePages(pCache));
+#endif
+      pcacheTrace(("%p.SPILL %d\n",pCache,pPg->pgno));
+      rc = pCache->xStress(pCache->pStress, pPg);
+      pcacheDump(pCache);
+      if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
+        return rc;
+      }
+    }
+  }
+  *ppPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, 2);
+  return *ppPage==0 ? SQLITE_NOMEM_BKPT : SQLITE_OK;
+}
+
+/*
+** This is a helper routine for sqlite3PcacheFetchFinish()
+**
+** In the uncommon case where the page being fetched has not been
+** initialized, this routine is invoked to do the initialization.
+** This routine is broken out into a separate function since it
+** requires extra stack manipulation that can be avoided in the common
+** case.
+*/
+static SQLITE_NOINLINE PgHdr *pcacheFetchFinishWithInit(
+  PCache *pCache,             /* Obtain the page from this cache */
+  Pgno pgno,                  /* Page number obtained */
+  sqlite3_pcache_page *pPage  /* Page obtained by prior PcacheFetch() call */
+){
+  PgHdr *pPgHdr;
+  assert( pPage!=0 );
+  pPgHdr = (PgHdr*)pPage->pExtra;
+  assert( pPgHdr->pPage==0 );
+  memset(&pPgHdr->pDirty, 0, sizeof(PgHdr) - offsetof(PgHdr,pDirty));
+  pPgHdr->pPage = pPage;
+  pPgHdr->pData = pPage->pBuf;
+  pPgHdr->pExtra = (void *)&pPgHdr[1];
+  memset(pPgHdr->pExtra, 0, 8);
+  assert( EIGHT_BYTE_ALIGNMENT( pPgHdr->pExtra ) );
+  pPgHdr->pCache = pCache;
+  pPgHdr->pgno = pgno;
+  pPgHdr->flags = PGHDR_CLEAN;
+  return sqlite3PcacheFetchFinish(pCache,pgno,pPage);
+}
+
+/*
+** This routine converts the sqlite3_pcache_page object returned by
+** sqlite3PcacheFetch() into an initialized PgHdr object.  This routine
+** must be called after sqlite3PcacheFetch() in order to get a usable
+** result.
+*/
+SQLITE_PRIVATE PgHdr *sqlite3PcacheFetchFinish(
+  PCache *pCache,             /* Obtain the page from this cache */
+  Pgno pgno,                  /* Page number obtained */
+  sqlite3_pcache_page *pPage  /* Page obtained by prior PcacheFetch() call */
+){
+  PgHdr *pPgHdr;
+
+  assert( pPage!=0 );
+  pPgHdr = (PgHdr *)pPage->pExtra;
+
+  if( !pPgHdr->pPage ){
+    return pcacheFetchFinishWithInit(pCache, pgno, pPage);
+  }
+  pCache->nRefSum++;
+  pPgHdr->nRef++;
+  assert( sqlite3PcachePageSanity(pPgHdr) );
+  return pPgHdr;
+}
+
+/*
+** Decrement the reference count on a page. If the page is clean and the
+** reference count drops to 0, then it is made eligible for recycling.
+*/
+SQLITE_PRIVATE void SQLITE_NOINLINE sqlite3PcacheRelease(PgHdr *p){
+  assert( p->nRef>0 );
+  p->pCache->nRefSum--;
+  if( (--p->nRef)==0 ){
+    if( p->flags&PGHDR_CLEAN ){
+      pcacheUnpin(p);
+    }else{
+      pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT);
+      assert( sqlite3PcachePageSanity(p) );
+    }
+  }
+}
+
+/*
+** Increase the reference count of a supplied page by 1.
+*/
+SQLITE_PRIVATE void sqlite3PcacheRef(PgHdr *p){
+  assert(p->nRef>0);
+  assert( sqlite3PcachePageSanity(p) );
+  p->nRef++;
+  p->pCache->nRefSum++;
+}
+
+/*
+** Drop a page from the cache. There must be exactly one reference to the
+** page. This function deletes that reference, so after it returns the
+** page pointed to by p is invalid.
+*/
+SQLITE_PRIVATE void sqlite3PcacheDrop(PgHdr *p){
+  assert( p->nRef==1 );
+  assert( sqlite3PcachePageSanity(p) );
+  if( p->flags&PGHDR_DIRTY ){
+    pcacheManageDirtyList(p, PCACHE_DIRTYLIST_REMOVE);
+  }
+  p->pCache->nRefSum--;
+  sqlite3GlobalConfig.pcache2.xUnpin(p->pCache->pCache, p->pPage, 1);
+}
+
+/*
+** Make sure the page is marked as dirty. If it isn't dirty already,
+** make it so.
+*/
+SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr *p){
+  assert( p->nRef>0 );
+  assert( sqlite3PcachePageSanity(p) );
+  if( p->flags & (PGHDR_CLEAN|PGHDR_DONT_WRITE) ){    /*OPTIMIZATION-IF-FALSE*/
+    p->flags &= ~PGHDR_DONT_WRITE;
+    if( p->flags & PGHDR_CLEAN ){
+      p->flags ^= (PGHDR_DIRTY|PGHDR_CLEAN);
+      pcacheTrace(("%p.DIRTY %d\n",p->pCache,p->pgno));
+      assert( (p->flags & (PGHDR_DIRTY|PGHDR_CLEAN))==PGHDR_DIRTY );
+      pcacheManageDirtyList(p, PCACHE_DIRTYLIST_ADD);
+      assert( sqlite3PcachePageSanity(p) );
+    }
+    assert( sqlite3PcachePageSanity(p) );
+  }
+}
+
+/*
+** Make sure the page is marked as clean. If it isn't clean already,
+** make it so.
+*/
+SQLITE_PRIVATE void sqlite3PcacheMakeClean(PgHdr *p){
+  assert( sqlite3PcachePageSanity(p) );
+  assert( (p->flags & PGHDR_DIRTY)!=0 );
+  assert( (p->flags & PGHDR_CLEAN)==0 );
+  pcacheManageDirtyList(p, PCACHE_DIRTYLIST_REMOVE);
+  p->flags &= ~(PGHDR_DIRTY|PGHDR_NEED_SYNC|PGHDR_WRITEABLE);
+  p->flags |= PGHDR_CLEAN;
+  pcacheTrace(("%p.CLEAN %d\n",p->pCache,p->pgno));
+  assert( sqlite3PcachePageSanity(p) );
+  if( p->nRef==0 ){
+    pcacheUnpin(p);
+  }
+}
+
+/*
+** Make every page in the cache clean.
+*/
+SQLITE_PRIVATE void sqlite3PcacheCleanAll(PCache *pCache){
+  PgHdr *p;
+  pcacheTrace(("%p.CLEAN-ALL\n",pCache));
+  while( (p = pCache->pDirty)!=0 ){
+    sqlite3PcacheMakeClean(p);
+  }
+}
+
+/*
+** Clear the PGHDR_NEED_SYNC and PGHDR_WRITEABLE flag from all dirty pages.
+*/
+SQLITE_PRIVATE void sqlite3PcacheClearWritable(PCache *pCache){
+  PgHdr *p;
+  pcacheTrace(("%p.CLEAR-WRITEABLE\n",pCache));
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    p->flags &= ~(PGHDR_NEED_SYNC|PGHDR_WRITEABLE);
+  }
+  pCache->pSynced = pCache->pDirtyTail;
+}
+
+/*
+** Clear the PGHDR_NEED_SYNC flag from all dirty pages.
+*/
+SQLITE_PRIVATE void sqlite3PcacheClearSyncFlags(PCache *pCache){
+  PgHdr *p;
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    p->flags &= ~PGHDR_NEED_SYNC;
+  }
+  pCache->pSynced = pCache->pDirtyTail;
+}
+
+/*
+** Change the page number of page p to newPgno.
+*/
+SQLITE_PRIVATE void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
+  PCache *pCache = p->pCache;
+  sqlite3_pcache_page *pOther;
+  assert( p->nRef>0 );
+  assert( newPgno>0 );
+  assert( sqlite3PcachePageSanity(p) );
+  pcacheTrace(("%p.MOVE %d -> %d\n",pCache,p->pgno,newPgno));
+  pOther = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, newPgno, 0);
+  if( pOther ){
+    PgHdr *pXPage = (PgHdr*)pOther->pExtra;
+    assert( pXPage->nRef==0 );
+    pXPage->nRef++;
+    pCache->nRefSum++;
+    sqlite3PcacheDrop(pXPage);
+  }
+  sqlite3GlobalConfig.pcache2.xRekey(pCache->pCache, p->pPage, p->pgno,newPgno);
+  p->pgno = newPgno;
+  if( (p->flags&PGHDR_DIRTY) && (p->flags&PGHDR_NEED_SYNC) ){
+    pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT);
+    assert( sqlite3PcachePageSanity(p) );
+  }
+}
+
+/*
+** Drop every cache entry whose page number is greater than "pgno". The
+** caller must ensure that there are no outstanding references to any pages
+** other than page 1 with a page number greater than pgno.
+**
+** If there is a reference to page 1 and the pgno parameter passed to this
+** function is 0, then the data area associated with page 1 is zeroed, but
+** the page object is not dropped.
+*/
+SQLITE_PRIVATE void sqlite3PcacheTruncate(PCache *pCache, Pgno pgno){
+  if( pCache->pCache ){
+    PgHdr *p;
+    PgHdr *pNext;
+    pcacheTrace(("%p.TRUNCATE %d\n",pCache,pgno));
+    for(p=pCache->pDirty; p; p=pNext){
+      pNext = p->pDirtyNext;
+      /* This routine never gets call with a positive pgno except right
+      ** after sqlite3PcacheCleanAll().  So if there are dirty pages,
+      ** it must be that pgno==0.
+      */
+      assert( p->pgno>0 );
+      if( p->pgno>pgno ){
+        assert( p->flags&PGHDR_DIRTY );
+        sqlite3PcacheMakeClean(p);
+      }
+    }
+    if( pgno==0 && pCache->nRefSum ){
+      sqlite3_pcache_page *pPage1;
+      pPage1 = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache,1,0);
+      if( ALWAYS(pPage1) ){  /* Page 1 is always available in cache, because
+                             ** pCache->nRefSum>0 */
+        memset(pPage1->pBuf, 0, pCache->szPage);
+        pgno = 1;
+      }
+    }
+    sqlite3GlobalConfig.pcache2.xTruncate(pCache->pCache, pgno+1);
+  }
+}
+
+/*
+** Close a cache.
+*/
+SQLITE_PRIVATE void sqlite3PcacheClose(PCache *pCache){
+  assert( pCache->pCache!=0 );
+  pcacheTrace(("%p.CLOSE\n",pCache));
+  sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
+}
+
+/*
+** Discard the contents of the cache.
+*/
+SQLITE_PRIVATE void sqlite3PcacheClear(PCache *pCache){
+  sqlite3PcacheTruncate(pCache, 0);
+}
+
+/*
+** Merge two lists of pages connected by pDirty and in pgno order.
+** Do not bother fixing the pDirtyPrev pointers.
+*/
+static PgHdr *pcacheMergeDirtyList(PgHdr *pA, PgHdr *pB){
+  PgHdr result, *pTail;
+  pTail = &result;
+  assert( pA!=0 && pB!=0 );
+  for(;;){
+    if( pA->pgno<pB->pgno ){
+      pTail->pDirty = pA;
+      pTail = pA;
+      pA = pA->pDirty;
+      if( pA==0 ){
+        pTail->pDirty = pB;
+        break;
+      }
+    }else{
+      pTail->pDirty = pB;
+      pTail = pB;
+      pB = pB->pDirty;
+      if( pB==0 ){
+        pTail->pDirty = pA;
+        break;
+      }
+    }
+  }
+  return result.pDirty;
+}
+
+/*
+** Sort the list of pages in ascending order by pgno.  Pages are
+** connected by pDirty pointers.  The pDirtyPrev pointers are
+** corrupted by this sort.
+**
+** Since there cannot be more than 2^31 distinct pages in a database,
+** there cannot be more than 31 buckets required by the merge sorter.
+** One extra bucket is added to catch overflow in case something
+** ever changes to make the previous sentence incorrect.
+*/
+#define N_SORT_BUCKET  32
+static PgHdr *pcacheSortDirtyList(PgHdr *pIn){
+  PgHdr *a[N_SORT_BUCKET], *p;
+  int i;
+  memset(a, 0, sizeof(a));
+  while( pIn ){
+    p = pIn;
+    pIn = p->pDirty;
+    p->pDirty = 0;
+    for(i=0; ALWAYS(i<N_SORT_BUCKET-1); i++){
+      if( a[i]==0 ){
+        a[i] = p;
+        break;
+      }else{
+        p = pcacheMergeDirtyList(a[i], p);
+        a[i] = 0;
+      }
+    }
+    if( NEVER(i==N_SORT_BUCKET-1) ){
+      /* To get here, there need to be 2^(N_SORT_BUCKET) elements in
+      ** the input list.  But that is impossible.
+      */
+      a[i] = pcacheMergeDirtyList(a[i], p);
+    }
+  }
+  p = a[0];
+  for(i=1; i<N_SORT_BUCKET; i++){
+    if( a[i]==0 ) continue;
+    p = p ? pcacheMergeDirtyList(p, a[i]) : a[i];
+  }
+  return p;
+}
+
+/*
+** Return a list of all dirty pages in the cache, sorted by page number.
+*/
+SQLITE_PRIVATE PgHdr *sqlite3PcacheDirtyList(PCache *pCache){
+  PgHdr *p;
+  for(p=pCache->pDirty; p; p=p->pDirtyNext){
+    p->pDirty = p->pDirtyNext;
+  }
+  return pcacheSortDirtyList(pCache->pDirty);
+}
+
+/*
+** Return the total number of references to all pages held by the cache.
+**
+** This is not the total number of pages referenced, but the sum of the
+** reference count for all pages.
+*/
+SQLITE_PRIVATE i64 sqlite3PcacheRefCount(PCache *pCache){
+  return pCache->nRefSum;
+}
+
+/*
+** Return the number of references to the page supplied as an argument.
+*/
+SQLITE_PRIVATE i64 sqlite3PcachePageRefcount(PgHdr *p){
+  return p->nRef;
+}
+
+/*
+** Return the total number of pages in the cache.
+*/
+SQLITE_PRIVATE int sqlite3PcachePagecount(PCache *pCache){
+  assert( pCache->pCache!=0 );
+  return sqlite3GlobalConfig.pcache2.xPagecount(pCache->pCache);
+}
+
+#ifdef SQLITE_TEST
+/*
+** Get the suggested cache-size value.
+*/
+SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *pCache){
+  return numberOfCachePages(pCache);
+}
+#endif
+
+/*
+** Set the suggested cache-size value.
+*/
+SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *pCache, int mxPage){
+  assert( pCache->pCache!=0 );
+  pCache->szCache = mxPage;
+  sqlite3GlobalConfig.pcache2.xCachesize(pCache->pCache,
+                                         numberOfCachePages(pCache));
+}
+
+/*
+** Set the suggested cache-spill value.  Make no changes if if the
+** argument is zero.  Return the effective cache-spill size, which will
+** be the larger of the szSpill and szCache.
+*/
+SQLITE_PRIVATE int sqlite3PcacheSetSpillsize(PCache *p, int mxPage){
+  int res;
+  assert( p->pCache!=0 );
+  if( mxPage ){
+    if( mxPage<0 ){
+      mxPage = (int)((-1024*(i64)mxPage)/(p->szPage+p->szExtra));
+    }
+    p->szSpill = mxPage;
+  }
+  res = numberOfCachePages(p);
+  if( res<p->szSpill ) res = p->szSpill;
+  return res;
+}
+
+/*
+** Free up as much memory as possible from the page cache.
+*/
+SQLITE_PRIVATE void sqlite3PcacheShrink(PCache *pCache){
+  assert( pCache->pCache!=0 );
+  sqlite3GlobalConfig.pcache2.xShrink(pCache->pCache);
+}
+
+/*
+** Return the size of the header added by this middleware layer
+** in the page-cache hierarchy.
+*/
+SQLITE_PRIVATE int sqlite3HeaderSizePcache(void){ return ROUND8(sizeof(PgHdr)); }
+
+/*
+** Return the number of dirty pages currently in the cache, as a percentage
+** of the configured cache size.
+*/
+SQLITE_PRIVATE int sqlite3PCachePercentDirty(PCache *pCache){
+  PgHdr *pDirty;
+  int nDirty = 0;
+  int nCache = numberOfCachePages(pCache);
+  for(pDirty=pCache->pDirty; pDirty; pDirty=pDirty->pDirtyNext) nDirty++;
+  return nCache ? (int)(((i64)nDirty * 100) / nCache) : 0;
+}
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+/*
+** Return true if there are one or more dirty pages in the cache. Else false.
+*/
+SQLITE_PRIVATE int sqlite3PCacheIsDirty(PCache *pCache){
+  return (pCache->pDirty!=0);
+}
+#endif
+
+#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
+/*
+** For all dirty pages currently in the cache, invoke the specified
+** callback. This is only used if the SQLITE_CHECK_PAGES macro is
+** defined.
+*/
+SQLITE_PRIVATE void sqlite3PcacheIterateDirty(PCache *pCache, void (*xIter)(PgHdr *)){
+  PgHdr *pDirty;
+  for(pDirty=pCache->pDirty; pDirty; pDirty=pDirty->pDirtyNext){
+    xIter(pDirty);
+  }
+}
+#endif
+
+/************** End of pcache.c **********************************************/
+/************** Begin file pcache1.c *****************************************/
+/*
+** 2008 November 05
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements the default page cache implementation (the
+** sqlite3_pcache interface). It also contains part of the implementation
+** of the SQLITE_CONFIG_PAGECACHE and sqlite3_release_memory() features.
+** If the default page cache implementation is overridden, then neither of
+** these two features are available.
+**
+** A Page cache line looks like this:
+**
+**  -------------------------------------------------------------
+**  |  database page content   |  PgHdr1  |  MemPage  |  PgHdr  |
+**  -------------------------------------------------------------
+**
+** The database page content is up front (so that buffer overreads tend to
+** flow harmlessly into the PgHdr1, MemPage, and PgHdr extensions).   MemPage
+** is the extension added by the btree.c module containing information such
+** as the database page number and how that database page is used.  PgHdr
+** is added by the pcache.c layer and contains information used to keep track
+** of which pages are "dirty".  PgHdr1 is an extension added by this
+** module (pcache1.c).  The PgHdr1 header is a subclass of sqlite3_pcache_page.
+** PgHdr1 contains information needed to look up a page by its page number.
+** The superclass sqlite3_pcache_page.pBuf points to the start of the
+** database page content and sqlite3_pcache_page.pExtra points to PgHdr.
+**
+** The size of the extension (MemPage+PgHdr+PgHdr1) can be determined at
+** runtime using sqlite3_config(SQLITE_CONFIG_PCACHE_HDRSZ, &size).  The
+** sizes of the extensions sum to 272 bytes on x64 for 3.8.10, but this
+** size can vary according to architecture, compile-time options, and
+** SQLite library version number.
+**
+** Historical note:  It used to be that if the SQLITE_PCACHE_SEPARATE_HEADER
+** was defined, then the page content would be held in a separate memory
+** allocation from the PgHdr1.  This was intended to avoid clownshoe memory
+** allocations.  However, the btree layer needs a small (16-byte) overrun
+** area after the page content buffer.  The header serves as that overrun
+** area.  Therefore SQLITE_PCACHE_SEPARATE_HEADER was discontinued to avoid
+** any possibility of a memory error.
+**
+** This module tracks pointers to PgHdr1 objects.  Only pcache.c communicates
+** with this module.  Information is passed back and forth as PgHdr1 pointers.
+**
+** The pcache.c and pager.c modules deal pointers to PgHdr objects.
+** The btree.c module deals with pointers to MemPage objects.
+**
+** SOURCE OF PAGE CACHE MEMORY:
+**
+** Memory for a page might come from any of three sources:
+**
+**    (1)  The general-purpose memory allocator - sqlite3Malloc()
+**    (2)  Global page-cache memory provided using sqlite3_config() with
+**         SQLITE_CONFIG_PAGECACHE.
+**    (3)  PCache-local bulk allocation.
+**
+** The third case is a chunk of heap memory (defaulting to 100 pages worth)
+** that is allocated when the page cache is created.  The size of the local
+** bulk allocation can be adjusted using
+**
+**     sqlite3_config(SQLITE_CONFIG_PAGECACHE, (void*)0, 0, N).
+**
+** If N is positive, then N pages worth of memory are allocated using a single
+** sqlite3Malloc() call and that memory is used for the first N pages allocated.
+** Or if N is negative, then -1024*N bytes of memory are allocated and used
+** for as many pages as can be accommodated.
+**
+** Only one of (2) or (3) can be used.  Once the memory available to (2) or
+** (3) is exhausted, subsequent allocations fail over to the general-purpose
+** memory allocator (1).
+**
+** Earlier versions of SQLite used only methods (1) and (2).  But experiments
+** show that method (3) with N==100 provides about a 5% performance boost for
+** common workloads.
+*/
+/* #include "sqliteInt.h" */
+
+typedef struct PCache1 PCache1;
+typedef struct PgHdr1 PgHdr1;
+typedef struct PgFreeslot PgFreeslot;
+typedef struct PGroup PGroup;
+
+/*
+** Each cache entry is represented by an instance of the following
+** structure. A buffer of PgHdr1.pCache->szPage bytes is allocated
+** directly before this structure and is used to cache the page content.
+**
+** When reading a corrupt database file, it is possible that SQLite might
+** read a few bytes (no more than 16 bytes) past the end of the page buffer.
+** It will only read past the end of the page buffer, never write.  This
+** object is positioned immediately after the page buffer to serve as an
+** overrun area, so that overreads are harmless.
+**
+** Variables isBulkLocal and isAnchor were once type "u8". That works,
+** but causes a 2-byte gap in the structure for most architectures (since
+** pointers must be either 4 or 8-byte aligned). As this structure is located
+** in memory directly after the associated page data, if the database is
+** corrupt, code at the b-tree layer may overread the page buffer and
+** read part of this structure before the corruption is detected. This
+** can cause a valgrind error if the uninitialized gap is accessed. Using u16
+** ensures there is no such gap, and therefore no bytes of uninitialized
+** memory in the structure.
+**
+** The pLruNext and pLruPrev pointers form a double-linked circular list
+** of all pages that are unpinned.  The PGroup.lru element (which should be
+** the only element on the list with PgHdr1.isAnchor set to 1) forms the
+** beginning and the end of the list.
+*/
+struct PgHdr1 {
+  sqlite3_pcache_page page; /* Base class. Must be first. pBuf & pExtra */
+  unsigned int iKey;        /* Key value (page number) */
+  u16 isBulkLocal;          /* This page from bulk local storage */
+  u16 isAnchor;             /* This is the PGroup.lru element */
+  PgHdr1 *pNext;            /* Next in hash table chain */
+  PCache1 *pCache;          /* Cache that currently owns this page */
+  PgHdr1 *pLruNext;         /* Next in circular LRU list of unpinned pages */
+  PgHdr1 *pLruPrev;         /* Previous in LRU list of unpinned pages */
+                            /* NB: pLruPrev is only valid if pLruNext!=0 */
+};
+
+/*
+** A page is pinned if it is not on the LRU list.  To be "pinned" means
+** that the page is in active use and must not be deallocated.
+*/
+#define PAGE_IS_PINNED(p)    ((p)->pLruNext==0)
+#define PAGE_IS_UNPINNED(p)  ((p)->pLruNext!=0)
+
+/* Each page cache (or PCache) belongs to a PGroup.  A PGroup is a set
+** of one or more PCaches that are able to recycle each other's unpinned
+** pages when they are under memory pressure.  A PGroup is an instance of
+** the following object.
+**
+** This page cache implementation works in one of two modes:
+**
+**   (1)  Every PCache is the sole member of its own PGroup.  There is
+**        one PGroup per PCache.
+**
+**   (2)  There is a single global PGroup that all PCaches are a member
+**        of.
+**
+** Mode 1 uses more memory (since PCache instances are not able to rob
+** unused pages from other PCaches) but it also operates without a mutex,
+** and is therefore often faster.  Mode 2 requires a mutex in order to be
+** threadsafe, but recycles pages more efficiently.
+**
+** For mode (1), PGroup.mutex is NULL.  For mode (2) there is only a single
+** PGroup which is the pcache1.grp global variable and its mutex is
+** SQLITE_MUTEX_STATIC_LRU.
+*/
+struct PGroup {
+  sqlite3_mutex *mutex;          /* MUTEX_STATIC_LRU or NULL */
+  unsigned int nMaxPage;         /* Sum of nMax for purgeable caches */
+  unsigned int nMinPage;         /* Sum of nMin for purgeable caches */
+  unsigned int mxPinned;         /* nMaxpage + 10 - nMinPage */
+  unsigned int nPurgeable;       /* Number of purgeable pages allocated */
+  PgHdr1 lru;                    /* The beginning and end of the LRU list */
+};
+
+/* Each page cache is an instance of the following object.  Every
+** open database file (including each in-memory database and each
+** temporary or transient database) has a single page cache which
+** is an instance of this object.
+**
+** Pointers to structures of this type are cast and returned as
+** opaque sqlite3_pcache* handles.
+*/
+struct PCache1 {
+  /* Cache configuration parameters. Page size (szPage) and the purgeable
+  ** flag (bPurgeable) and the pnPurgeable pointer are all set when the
+  ** cache is created and are never changed thereafter. nMax may be
+  ** modified at any time by a call to the pcache1Cachesize() method.
+  ** The PGroup mutex must be held when accessing nMax.
+  */
+  PGroup *pGroup;                     /* PGroup this cache belongs to */
+  unsigned int *pnPurgeable;          /* Pointer to pGroup->nPurgeable */
+  int szPage;                         /* Size of database content section */
+  int szExtra;                        /* sizeof(MemPage)+sizeof(PgHdr) */
+  int szAlloc;                        /* Total size of one pcache line */
+  int bPurgeable;                     /* True if cache is purgeable */
+  unsigned int nMin;                  /* Minimum number of pages reserved */
+  unsigned int nMax;                  /* Configured "cache_size" value */
+  unsigned int n90pct;                /* nMax*9/10 */
+  unsigned int iMaxKey;               /* Largest key seen since xTruncate() */
+  unsigned int nPurgeableDummy;       /* pnPurgeable points here when not used*/
+
+  /* Hash table of all pages. The following variables may only be accessed
+  ** when the accessor is holding the PGroup mutex.
+  */
+  unsigned int nRecyclable;           /* Number of pages in the LRU list */
+  unsigned int nPage;                 /* Total number of pages in apHash */
+  unsigned int nHash;                 /* Number of slots in apHash[] */
+  PgHdr1 **apHash;                    /* Hash table for fast lookup by key */
+  PgHdr1 *pFree;                      /* List of unused pcache-local pages */
+  void *pBulk;                        /* Bulk memory used by pcache-local */
+};
+
+/*
+** Free slots in the allocator used to divide up the global page cache
+** buffer provided using the SQLITE_CONFIG_PAGECACHE mechanism.
+*/
+struct PgFreeslot {
+  PgFreeslot *pNext;  /* Next free slot */
+};
+
+/*
+** Global data used by this cache.
+*/
+static SQLITE_WSD struct PCacheGlobal {
+  PGroup grp;                    /* The global PGroup for mode (2) */
+
+  /* Variables related to SQLITE_CONFIG_PAGECACHE settings.  The
+  ** szSlot, nSlot, pStart, pEnd, nReserve, and isInit values are all
+  ** fixed at sqlite3_initialize() time and do not require mutex protection.
+  ** The nFreeSlot and pFree values do require mutex protection.
+  */
+  int isInit;                    /* True if initialized */
+  int separateCache;             /* Use a new PGroup for each PCache */
+  int nInitPage;                 /* Initial bulk allocation size */
+  int szSlot;                    /* Size of each free slot */
+  int nSlot;                     /* The number of pcache slots */
+  int nReserve;                  /* Try to keep nFreeSlot above this */
+  void *pStart, *pEnd;           /* Bounds of global page cache memory */
+  /* Above requires no mutex.  Use mutex below for variable that follow. */
+  sqlite3_mutex *mutex;          /* Mutex for accessing the following: */
+  PgFreeslot *pFree;             /* Free page blocks */
+  int nFreeSlot;                 /* Number of unused pcache slots */
+  /* The following value requires a mutex to change.  We skip the mutex on
+  ** reading because (1) most platforms read a 32-bit integer atomically and
+  ** (2) even if an incorrect value is read, no great harm is done since this
+  ** is really just an optimization. */
+  int bUnderPressure;            /* True if low on PAGECACHE memory */
+} pcache1_g;
+
+/*
+** All code in this file should access the global structure above via the
+** alias "pcache1". This ensures that the WSD emulation is used when
+** compiling for systems that do not support real WSD.
+*/
+#define pcache1 (GLOBAL(struct PCacheGlobal, pcache1_g))
+
+/*
+** Macros to enter and leave the PCache LRU mutex.
+*/
+#if !defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) || SQLITE_THREADSAFE==0
+# define pcache1EnterMutex(X)  assert((X)->mutex==0)
+# define pcache1LeaveMutex(X)  assert((X)->mutex==0)
+# define PCACHE1_MIGHT_USE_GROUP_MUTEX 0
+#else
+# define pcache1EnterMutex(X) sqlite3_mutex_enter((X)->mutex)
+# define pcache1LeaveMutex(X) sqlite3_mutex_leave((X)->mutex)
+# define PCACHE1_MIGHT_USE_GROUP_MUTEX 1
+#endif
+
+/******************************************************************************/
+/******** Page Allocation/SQLITE_CONFIG_PCACHE Related Functions **************/
+
+
+/*
+** This function is called during initialization if a static buffer is
+** supplied to use for the page-cache by passing the SQLITE_CONFIG_PAGECACHE
+** verb to sqlite3_config(). Parameter pBuf points to an allocation large
+** enough to contain 'n' buffers of 'sz' bytes each.
+**
+** This routine is called from sqlite3_initialize() and so it is guaranteed
+** to be serialized already.  There is no need for further mutexing.
+*/
+SQLITE_PRIVATE void sqlite3PCacheBufferSetup(void *pBuf, int sz, int n){
+  if( pcache1.isInit ){
+    PgFreeslot *p;
+    if( pBuf==0 ) sz = n = 0;
+    if( n==0 ) sz = 0;
+    sz = ROUNDDOWN8(sz);
+    pcache1.szSlot = sz;
+    pcache1.nSlot = pcache1.nFreeSlot = n;
+    pcache1.nReserve = n>90 ? 10 : (n/10 + 1);
+    pcache1.pStart = pBuf;
+    pcache1.pFree = 0;
+    pcache1.bUnderPressure = 0;
+    while( n-- ){
+      p = (PgFreeslot*)pBuf;
+      p->pNext = pcache1.pFree;
+      pcache1.pFree = p;
+      pBuf = (void*)&((char*)pBuf)[sz];
+    }
+    pcache1.pEnd = pBuf;
+  }
+}
+
+/*
+** Try to initialize the pCache->pFree and pCache->pBulk fields.  Return
+** true if pCache->pFree ends up containing one or more free pages.
+*/
+static int pcache1InitBulk(PCache1 *pCache){
+  i64 szBulk;
+  char *zBulk;
+  if( pcache1.nInitPage==0 ) return 0;
+  /* Do not bother with a bulk allocation if the cache size very small */
+  if( pCache->nMax<3 ) return 0;
+  sqlite3BeginBenignMalloc();
+  if( pcache1.nInitPage>0 ){
+    szBulk = pCache->szAlloc * (i64)pcache1.nInitPage;
+  }else{
+    szBulk = -1024 * (i64)pcache1.nInitPage;
+  }
+  if( szBulk > pCache->szAlloc*(i64)pCache->nMax ){
+    szBulk = pCache->szAlloc*(i64)pCache->nMax;
+  }
+  zBulk = pCache->pBulk = sqlite3Malloc( szBulk );
+  sqlite3EndBenignMalloc();
+  if( zBulk ){
+    int nBulk = sqlite3MallocSize(zBulk)/pCache->szAlloc;
+    do{
+      PgHdr1 *pX = (PgHdr1*)&zBulk[pCache->szPage];
+      pX->page.pBuf = zBulk;
+      pX->page.pExtra = (u8*)pX + ROUND8(sizeof(*pX));
+      assert( EIGHT_BYTE_ALIGNMENT( pX->page.pExtra ) );
+      pX->isBulkLocal = 1;
+      pX->isAnchor = 0;
+      pX->pNext = pCache->pFree;
+      pX->pLruPrev = 0;           /* Initializing this saves a valgrind error */
+      pCache->pFree = pX;
+      zBulk += pCache->szAlloc;
+    }while( --nBulk );
+  }
+  return pCache->pFree!=0;
+}
+
+/*
+** Malloc function used within this file to allocate space from the buffer
+** configured using sqlite3_config(SQLITE_CONFIG_PAGECACHE) option. If no
+** such buffer exists or there is no space left in it, this function falls
+** back to sqlite3Malloc().
+**
+** Multiple threads can run this routine at the same time.  Global variables
+** in pcache1 need to be protected via mutex.
+*/
+static void *pcache1Alloc(int nByte){
+  void *p = 0;
+  assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
+  if( nByte<=pcache1.szSlot ){
+    sqlite3_mutex_enter(pcache1.mutex);
+    p = (PgHdr1 *)pcache1.pFree;
+    if( p ){
+      pcache1.pFree = pcache1.pFree->pNext;
+      pcache1.nFreeSlot--;
+      pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve;
+      assert( pcache1.nFreeSlot>=0 );
+      sqlite3StatusHighwater(SQLITE_STATUS_PAGECACHE_SIZE, nByte);
+      sqlite3StatusUp(SQLITE_STATUS_PAGECACHE_USED, 1);
+    }
+    sqlite3_mutex_leave(pcache1.mutex);
+  }
+  if( p==0 ){
+    /* Memory is not available in the SQLITE_CONFIG_PAGECACHE pool.  Get
+    ** it from sqlite3Malloc instead.
+    */
+    p = sqlite3Malloc(nByte);
+#ifndef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
+    if( p ){
+      int sz = sqlite3MallocSize(p);
+      sqlite3_mutex_enter(pcache1.mutex);
+      sqlite3StatusHighwater(SQLITE_STATUS_PAGECACHE_SIZE, nByte);
+      sqlite3StatusUp(SQLITE_STATUS_PAGECACHE_OVERFLOW, sz);
+      sqlite3_mutex_leave(pcache1.mutex);
+    }
+#endif
+    sqlite3MemdebugSetType(p, MEMTYPE_PCACHE);
+  }
+  return p;
+}
+
+/*
+** Free an allocated buffer obtained from pcache1Alloc().
+*/
+static void pcache1Free(void *p){
+  if( p==0 ) return;
+  if( SQLITE_WITHIN(p, pcache1.pStart, pcache1.pEnd) ){
+    PgFreeslot *pSlot;
+    sqlite3_mutex_enter(pcache1.mutex);
+    sqlite3StatusDown(SQLITE_STATUS_PAGECACHE_USED, 1);
+    pSlot = (PgFreeslot*)p;
+    pSlot->pNext = pcache1.pFree;
+    pcache1.pFree = pSlot;
+    pcache1.nFreeSlot++;
+    pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve;
+    assert( pcache1.nFreeSlot<=pcache1.nSlot );
+    sqlite3_mutex_leave(pcache1.mutex);
+  }else{
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
+    sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+#ifndef SQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
+    {
+      int nFreed = 0;
+      nFreed = sqlite3MallocSize(p);
+      sqlite3_mutex_enter(pcache1.mutex);
+      sqlite3StatusDown(SQLITE_STATUS_PAGECACHE_OVERFLOW, nFreed);
+      sqlite3_mutex_leave(pcache1.mutex);
+    }
+#endif
+    sqlite3_free(p);
+  }
+}
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/*
+** Return the size of a pcache allocation
+*/
+static int pcache1MemSize(void *p){
+  if( p>=pcache1.pStart && p<pcache1.pEnd ){
+    return pcache1.szSlot;
+  }else{
+    int iSize;
+    assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
+    sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
+    iSize = sqlite3MallocSize(p);
+    sqlite3MemdebugSetType(p, MEMTYPE_PCACHE);
+    return iSize;
+  }
+}
+#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */
+
+/*
+** Allocate a new page object initially associated with cache pCache.
+*/
+static PgHdr1 *pcache1AllocPage(PCache1 *pCache, int benignMalloc){
+  PgHdr1 *p = 0;
+  void *pPg;
+
+  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
+  if( pCache->pFree || (pCache->nPage==0 && pcache1InitBulk(pCache)) ){
+    assert( pCache->pFree!=0 );
+    p = pCache->pFree;
+    pCache->pFree = p->pNext;
+    p->pNext = 0;
+  }else{
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+    /* The group mutex must be released before pcache1Alloc() is called. This
+    ** is because it might call sqlite3_release_memory(), which assumes that
+    ** this mutex is not held. */
+    assert( pcache1.separateCache==0 );
+    assert( pCache->pGroup==&pcache1.grp );
+    pcache1LeaveMutex(pCache->pGroup);
+#endif
+    if( benignMalloc ){ sqlite3BeginBenignMalloc(); }
+    pPg = pcache1Alloc(pCache->szAlloc);
+    if( benignMalloc ){ sqlite3EndBenignMalloc(); }
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+    pcache1EnterMutex(pCache->pGroup);
+#endif
+    if( pPg==0 ) return 0;
+    p = (PgHdr1 *)&((u8 *)pPg)[pCache->szPage];
+    p->page.pBuf = pPg;
+    p->page.pExtra = (u8*)p + ROUND8(sizeof(*p));
+    assert( EIGHT_BYTE_ALIGNMENT( p->page.pExtra ) );
+    p->isBulkLocal = 0;
+    p->isAnchor = 0;
+    p->pLruPrev = 0;           /* Initializing this saves a valgrind error */
+  }
+  (*pCache->pnPurgeable)++;
+  return p;
+}
+
+/*
+** Free a page object allocated by pcache1AllocPage().
+*/
+static void pcache1FreePage(PgHdr1 *p){
+  PCache1 *pCache;
+  assert( p!=0 );
+  pCache = p->pCache;
+  assert( sqlite3_mutex_held(p->pCache->pGroup->mutex) );
+  if( p->isBulkLocal ){
+    p->pNext = pCache->pFree;
+    pCache->pFree = p;
+  }else{
+    pcache1Free(p->page.pBuf);
+  }
+  (*pCache->pnPurgeable)--;
+}
+
+/*
+** Malloc function used by SQLite to obtain space from the buffer configured
+** using sqlite3_config(SQLITE_CONFIG_PAGECACHE) option. If no such buffer
+** exists, this function falls back to sqlite3Malloc().
+*/
+SQLITE_PRIVATE void *sqlite3PageMalloc(int sz){
+  assert( sz<=65536+8 ); /* These allocations are never very large */
+  return pcache1Alloc(sz);
+}
+
+/*
+** Free an allocated buffer obtained from sqlite3PageMalloc().
+*/
+SQLITE_PRIVATE void sqlite3PageFree(void *p){
+  pcache1Free(p);
+}
+
+
+/*
+** Return true if it desirable to avoid allocating a new page cache
+** entry.
+**
+** If memory was allocated specifically to the page cache using
+** SQLITE_CONFIG_PAGECACHE but that memory has all been used, then
+** it is desirable to avoid allocating a new page cache entry because
+** presumably SQLITE_CONFIG_PAGECACHE was suppose to be sufficient
+** for all page cache needs and we should not need to spill the
+** allocation onto the heap.
+**
+** Or, the heap is used for all page cache memory but the heap is
+** under memory pressure, then again it is desirable to avoid
+** allocating a new page cache entry in order to avoid stressing
+** the heap even further.
+*/
+static int pcache1UnderMemoryPressure(PCache1 *pCache){
+  if( pcache1.nSlot && (pCache->szPage+pCache->szExtra)<=pcache1.szSlot ){
+    return pcache1.bUnderPressure;
+  }else{
+    return sqlite3HeapNearlyFull();
+  }
+}
+
+/******************************************************************************/
+/******** General Implementation Functions ************************************/
+
+/*
+** This function is used to resize the hash table used by the cache passed
+** as the first argument.
+**
+** The PCache mutex must be held when this function is called.
+*/
+static void pcache1ResizeHash(PCache1 *p){
+  PgHdr1 **apNew;
+  unsigned int nNew;
+  unsigned int i;
+
+  assert( sqlite3_mutex_held(p->pGroup->mutex) );
+
+  nNew = p->nHash*2;
+  if( nNew<256 ){
+    nNew = 256;
+  }
+
+  pcache1LeaveMutex(p->pGroup);
+  if( p->nHash ){ sqlite3BeginBenignMalloc(); }
+  apNew = (PgHdr1 **)sqlite3MallocZero(sizeof(PgHdr1 *)*nNew);
+  if( p->nHash ){ sqlite3EndBenignMalloc(); }
+  pcache1EnterMutex(p->pGroup);
+  if( apNew ){
+    for(i=0; i<p->nHash; i++){
+      PgHdr1 *pPage;
+      PgHdr1 *pNext = p->apHash[i];
+      while( (pPage = pNext)!=0 ){
+        unsigned int h = pPage->iKey % nNew;
+        pNext = pPage->pNext;
+        pPage->pNext = apNew[h];
+        apNew[h] = pPage;
+      }
+    }
+    sqlite3_free(p->apHash);
+    p->apHash = apNew;
+    p->nHash = nNew;
+  }
+}
+
+/*
+** This function is used internally to remove the page pPage from the
+** PGroup LRU list, if is part of it. If pPage is not part of the PGroup
+** LRU list, then this function is a no-op.
+**
+** The PGroup mutex must be held when this function is called.
+*/
+static PgHdr1 *pcache1PinPage(PgHdr1 *pPage){
+  assert( pPage!=0 );
+  assert( PAGE_IS_UNPINNED(pPage) );
+  assert( pPage->pLruNext );
+  assert( pPage->pLruPrev );
+  assert( sqlite3_mutex_held(pPage->pCache->pGroup->mutex) );
+  pPage->pLruPrev->pLruNext = pPage->pLruNext;
+  pPage->pLruNext->pLruPrev = pPage->pLruPrev;
+  pPage->pLruNext = 0;
+  /* pPage->pLruPrev = 0;
+  ** No need to clear pLruPrev as it is never accessed if pLruNext is 0 */
+  assert( pPage->isAnchor==0 );
+  assert( pPage->pCache->pGroup->lru.isAnchor==1 );
+  pPage->pCache->nRecyclable--;
+  return pPage;
+}
+
+
+/*
+** Remove the page supplied as an argument from the hash table
+** (PCache1.apHash structure) that it is currently stored in.
+** Also free the page if freePage is true.
+**
+** The PGroup mutex must be held when this function is called.
+*/
+static void pcache1RemoveFromHash(PgHdr1 *pPage, int freeFlag){
+  unsigned int h;
+  PCache1 *pCache = pPage->pCache;
+  PgHdr1 **pp;
+
+  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
+  h = pPage->iKey % pCache->nHash;
+  for(pp=&pCache->apHash[h]; (*pp)!=pPage; pp=&(*pp)->pNext);
+  *pp = (*pp)->pNext;
+
+  pCache->nPage--;
+  if( freeFlag ) pcache1FreePage(pPage);
+}
+
+/*
+** If there are currently more than nMaxPage pages allocated, try
+** to recycle pages to reduce the number allocated to nMaxPage.
+*/
+static void pcache1EnforceMaxPage(PCache1 *pCache){
+  PGroup *pGroup = pCache->pGroup;
+  PgHdr1 *p;
+  assert( sqlite3_mutex_held(pGroup->mutex) );
+  while( pGroup->nPurgeable>pGroup->nMaxPage
+      && (p=pGroup->lru.pLruPrev)->isAnchor==0
+  ){
+    assert( p->pCache->pGroup==pGroup );
+    assert( PAGE_IS_UNPINNED(p) );
+    pcache1PinPage(p);
+    pcache1RemoveFromHash(p, 1);
+  }
+  if( pCache->nPage==0 && pCache->pBulk ){
+    sqlite3_free(pCache->pBulk);
+    pCache->pBulk = pCache->pFree = 0;
+  }
+}
+
+/*
+** Discard all pages from cache pCache with a page number (key value)
+** greater than or equal to iLimit. Any pinned pages that meet this
+** criteria are unpinned before they are discarded.
+**
+** The PCache mutex must be held when this function is called.
+*/
+static void pcache1TruncateUnsafe(
+  PCache1 *pCache,             /* The cache to truncate */
+  unsigned int iLimit          /* Drop pages with this pgno or larger */
+){
+  TESTONLY( int nPage = 0; )  /* To assert pCache->nPage is correct */
+  unsigned int h, iStop;
+  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
+  assert( pCache->iMaxKey >= iLimit );
+  assert( pCache->nHash > 0 );
+  if( pCache->iMaxKey - iLimit < pCache->nHash ){
+    /* If we are just shaving the last few pages off the end of the
+    ** cache, then there is no point in scanning the entire hash table.
+    ** Only scan those hash slots that might contain pages that need to
+    ** be removed. */
+    h = iLimit % pCache->nHash;
+    iStop = pCache->iMaxKey % pCache->nHash;
+    TESTONLY( nPage = -10; )  /* Disable the pCache->nPage validity check */
+  }else{
+    /* This is the general case where many pages are being removed.
+    ** It is necessary to scan the entire hash table */
+    h = pCache->nHash/2;
+    iStop = h - 1;
+  }
+  for(;;){
+    PgHdr1 **pp;
+    PgHdr1 *pPage;
+    assert( h<pCache->nHash );
+    pp = &pCache->apHash[h];
+    while( (pPage = *pp)!=0 ){
+      if( pPage->iKey>=iLimit ){
+        pCache->nPage--;
+        *pp = pPage->pNext;
+        if( PAGE_IS_UNPINNED(pPage) ) pcache1PinPage(pPage);
+        pcache1FreePage(pPage);
+      }else{
+        pp = &pPage->pNext;
+        TESTONLY( if( nPage>=0 ) nPage++; )
+      }
+    }
+    if( h==iStop ) break;
+    h = (h+1) % pCache->nHash;
+  }
+  assert( nPage<0 || pCache->nPage==(unsigned)nPage );
+}
+
+/******************************************************************************/
+/******** sqlite3_pcache Methods **********************************************/
+
+/*
+** Implementation of the sqlite3_pcache.xInit method.
+*/
+static int pcache1Init(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  assert( pcache1.isInit==0 );
+  memset(&pcache1, 0, sizeof(pcache1));
+
+
+  /*
+  ** The pcache1.separateCache variable is true if each PCache has its own
+  ** private PGroup (mode-1).  pcache1.separateCache is false if the single
+  ** PGroup in pcache1.grp is used for all page caches (mode-2).
+  **
+  **   *  Always use a unified cache (mode-2) if ENABLE_MEMORY_MANAGEMENT
+  **
+  **   *  Use a unified cache in single-threaded applications that have
+  **      configured a start-time buffer for use as page-cache memory using
+  **      sqlite3_config(SQLITE_CONFIG_PAGECACHE, pBuf, sz, N) with non-NULL
+  **      pBuf argument.
+  **
+  **   *  Otherwise use separate caches (mode-1)
+  */
+#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT)
+  pcache1.separateCache = 0;
+#elif SQLITE_THREADSAFE
+  pcache1.separateCache = sqlite3GlobalConfig.pPage==0
+                          || sqlite3GlobalConfig.bCoreMutex>0;
+#else
+  pcache1.separateCache = sqlite3GlobalConfig.pPage==0;
+#endif
+
+#if SQLITE_THREADSAFE
+  if( sqlite3GlobalConfig.bCoreMutex ){
+    pcache1.grp.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_LRU);
+    pcache1.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_PMEM);
+  }
+#endif
+  if( pcache1.separateCache
+   && sqlite3GlobalConfig.nPage!=0
+   && sqlite3GlobalConfig.pPage==0
+  ){
+    pcache1.nInitPage = sqlite3GlobalConfig.nPage;
+  }else{
+    pcache1.nInitPage = 0;
+  }
+  pcache1.grp.mxPinned = 10;
+  pcache1.isInit = 1;
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of the sqlite3_pcache.xShutdown method.
+** Note that the static mutex allocated in xInit does
+** not need to be freed.
+*/
+static void pcache1Shutdown(void *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  assert( pcache1.isInit!=0 );
+  memset(&pcache1, 0, sizeof(pcache1));
+}
+
+/* forward declaration */
+static void pcache1Destroy(sqlite3_pcache *p);
+
+/*
+** Implementation of the sqlite3_pcache.xCreate method.
+**
+** Allocate a new cache.
+*/
+static sqlite3_pcache *pcache1Create(int szPage, int szExtra, int bPurgeable){
+  PCache1 *pCache;      /* The newly created page cache */
+  PGroup *pGroup;       /* The group the new page cache will belong to */
+  int sz;               /* Bytes of memory required to allocate the new cache */
+
+  assert( (szPage & (szPage-1))==0 && szPage>=512 && szPage<=65536 );
+  assert( szExtra < 300 );
+
+  sz = sizeof(PCache1) + sizeof(PGroup)*pcache1.separateCache;
+  pCache = (PCache1 *)sqlite3MallocZero(sz);
+  if( pCache ){
+    if( pcache1.separateCache ){
+      pGroup = (PGroup*)&pCache[1];
+      pGroup->mxPinned = 10;
+    }else{
+      pGroup = &pcache1.grp;
+    }
+    pcache1EnterMutex(pGroup);
+    if( pGroup->lru.isAnchor==0 ){
+      pGroup->lru.isAnchor = 1;
+      pGroup->lru.pLruPrev = pGroup->lru.pLruNext = &pGroup->lru;
+    }
+    pCache->pGroup = pGroup;
+    pCache->szPage = szPage;
+    pCache->szExtra = szExtra;
+    pCache->szAlloc = szPage + szExtra + ROUND8(sizeof(PgHdr1));
+    pCache->bPurgeable = (bPurgeable ? 1 : 0);
+    pcache1ResizeHash(pCache);
+    if( bPurgeable ){
+      pCache->nMin = 10;
+      pGroup->nMinPage += pCache->nMin;
+      pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
+      pCache->pnPurgeable = &pGroup->nPurgeable;
+    }else{
+      pCache->pnPurgeable = &pCache->nPurgeableDummy;
+    }
+    pcache1LeaveMutex(pGroup);
+    if( pCache->nHash==0 ){
+      pcache1Destroy((sqlite3_pcache*)pCache);
+      pCache = 0;
+    }
+  }
+  return (sqlite3_pcache *)pCache;
+}
+
+/*
+** Implementation of the sqlite3_pcache.xCachesize method.
+**
+** Configure the cache_size limit for a cache.
+*/
+static void pcache1Cachesize(sqlite3_pcache *p, int nMax){
+  PCache1 *pCache = (PCache1 *)p;
+  u32 n;
+  assert( nMax>=0 );
+  if( pCache->bPurgeable ){
+    PGroup *pGroup = pCache->pGroup;
+    pcache1EnterMutex(pGroup);
+    n = (u32)nMax;
+    if( n > 0x7fff0000 - pGroup->nMaxPage + pCache->nMax ){
+      n = 0x7fff0000 - pGroup->nMaxPage + pCache->nMax;
+    }
+    pGroup->nMaxPage += (n - pCache->nMax);
+    pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
+    pCache->nMax = n;
+    pCache->n90pct = pCache->nMax*9/10;
+    pcache1EnforceMaxPage(pCache);
+    pcache1LeaveMutex(pGroup);
+  }
+}
+
+/*
+** Implementation of the sqlite3_pcache.xShrink method.
+**
+** Free up as much memory as possible.
+*/
+static void pcache1Shrink(sqlite3_pcache *p){
+  PCache1 *pCache = (PCache1*)p;
+  if( pCache->bPurgeable ){
+    PGroup *pGroup = pCache->pGroup;
+    unsigned int savedMaxPage;
+    pcache1EnterMutex(pGroup);
+    savedMaxPage = pGroup->nMaxPage;
+    pGroup->nMaxPage = 0;
+    pcache1EnforceMaxPage(pCache);
+    pGroup->nMaxPage = savedMaxPage;
+    pcache1LeaveMutex(pGroup);
+  }
+}
+
+/*
+** Implementation of the sqlite3_pcache.xPagecount method.
+*/
+static int pcache1Pagecount(sqlite3_pcache *p){
+  int n;
+  PCache1 *pCache = (PCache1*)p;
+  pcache1EnterMutex(pCache->pGroup);
+  n = pCache->nPage;
+  pcache1LeaveMutex(pCache->pGroup);
+  return n;
+}
+
+
+/*
+** Implement steps 3, 4, and 5 of the pcache1Fetch() algorithm described
+** in the header of the pcache1Fetch() procedure.
+**
+** This steps are broken out into a separate procedure because they are
+** usually not needed, and by avoiding the stack initialization required
+** for these steps, the main pcache1Fetch() procedure can run faster.
+*/
+static SQLITE_NOINLINE PgHdr1 *pcache1FetchStage2(
+  PCache1 *pCache,
+  unsigned int iKey,
+  int createFlag
+){
+  unsigned int nPinned;
+  PGroup *pGroup = pCache->pGroup;
+  PgHdr1 *pPage = 0;
+
+  /* Step 3: Abort if createFlag is 1 but the cache is nearly full */
+  assert( pCache->nPage >= pCache->nRecyclable );
+  nPinned = pCache->nPage - pCache->nRecyclable;
+  assert( pGroup->mxPinned == pGroup->nMaxPage + 10 - pGroup->nMinPage );
+  assert( pCache->n90pct == pCache->nMax*9/10 );
+  if( createFlag==1 && (
+        nPinned>=pGroup->mxPinned
+     || nPinned>=pCache->n90pct
+     || (pcache1UnderMemoryPressure(pCache) && pCache->nRecyclable<nPinned)
+  )){
+    return 0;
+  }
+
+  if( pCache->nPage>=pCache->nHash ) pcache1ResizeHash(pCache);
+  assert( pCache->nHash>0 && pCache->apHash );
+
+  /* Step 4. Try to recycle a page. */
+  if( pCache->bPurgeable
+   && !pGroup->lru.pLruPrev->isAnchor
+   && ((pCache->nPage+1>=pCache->nMax) || pcache1UnderMemoryPressure(pCache))
+  ){
+    PCache1 *pOther;
+    pPage = pGroup->lru.pLruPrev;
+    assert( PAGE_IS_UNPINNED(pPage) );
+    pcache1RemoveFromHash(pPage, 0);
+    pcache1PinPage(pPage);
+    pOther = pPage->pCache;
+    if( pOther->szAlloc != pCache->szAlloc ){
+      pcache1FreePage(pPage);
+      pPage = 0;
+    }else{
+      pGroup->nPurgeable -= (pOther->bPurgeable - pCache->bPurgeable);
+    }
+  }
+
+  /* Step 5. If a usable page buffer has still not been found,
+  ** attempt to allocate a new one.
+  */
+  if( !pPage ){
+    pPage = pcache1AllocPage(pCache, createFlag==1);
+  }
+
+  if( pPage ){
+    unsigned int h = iKey % pCache->nHash;
+    pCache->nPage++;
+    pPage->iKey = iKey;
+    pPage->pNext = pCache->apHash[h];
+    pPage->pCache = pCache;
+    pPage->pLruNext = 0;
+    /* pPage->pLruPrev = 0;
+    ** No need to clear pLruPrev since it is not accessed when pLruNext==0 */
+    *(void **)pPage->page.pExtra = 0;
+    pCache->apHash[h] = pPage;
+    if( iKey>pCache->iMaxKey ){
+      pCache->iMaxKey = iKey;
+    }
+  }
+  return pPage;
+}
+
+/*
+** Implementation of the sqlite3_pcache.xFetch method.
+**
+** Fetch a page by key value.
+**
+** Whether or not a new page may be allocated by this function depends on
+** the value of the createFlag argument.  0 means do not allocate a new
+** page.  1 means allocate a new page if space is easily available.  2
+** means to try really hard to allocate a new page.
+**
+** For a non-purgeable cache (a cache used as the storage for an in-memory
+** database) there is really no difference between createFlag 1 and 2.  So
+** the calling function (pcache.c) will never have a createFlag of 1 on
+** a non-purgeable cache.
+**
+** There are three different approaches to obtaining space for a page,
+** depending on the value of parameter createFlag (which may be 0, 1 or 2).
+**
+**   1. Regardless of the value of createFlag, the cache is searched for a
+**      copy of the requested page. If one is found, it is returned.
+**
+**   2. If createFlag==0 and the page is not already in the cache, NULL is
+**      returned.
+**
+**   3. If createFlag is 1, and the page is not already in the cache, then
+**      return NULL (do not allocate a new page) if any of the following
+**      conditions are true:
+**
+**       (a) the number of pages pinned by the cache is greater than
+**           PCache1.nMax, or
+**
+**       (b) the number of pages pinned by the cache is greater than
+**           the sum of nMax for all purgeable caches, less the sum of
+**           nMin for all other purgeable caches, or
+**
+**   4. If none of the first three conditions apply and the cache is marked
+**      as purgeable, and if one of the following is true:
+**
+**       (a) The number of pages allocated for the cache is already
+**           PCache1.nMax, or
+**
+**       (b) The number of pages allocated for all purgeable caches is
+**           already equal to or greater than the sum of nMax for all
+**           purgeable caches,
+**
+**       (c) The system is under memory pressure and wants to avoid
+**           unnecessary pages cache entry allocations
+**
+**      then attempt to recycle a page from the LRU list. If it is the right
+**      size, return the recycled buffer. Otherwise, free the buffer and
+**      proceed to step 5.
+**
+**   5. Otherwise, allocate and return a new page buffer.
+**
+** There are two versions of this routine.  pcache1FetchWithMutex() is
+** the general case.  pcache1FetchNoMutex() is a faster implementation for
+** the common case where pGroup->mutex is NULL.  The pcache1Fetch() wrapper
+** invokes the appropriate routine.
+*/
+static PgHdr1 *pcache1FetchNoMutex(
+  sqlite3_pcache *p,
+  unsigned int iKey,
+  int createFlag
+){
+  PCache1 *pCache = (PCache1 *)p;
+  PgHdr1 *pPage = 0;
+
+  /* Step 1: Search the hash table for an existing entry. */
+  pPage = pCache->apHash[iKey % pCache->nHash];
+  while( pPage && pPage->iKey!=iKey ){ pPage = pPage->pNext; }
+
+  /* Step 2: If the page was found in the hash table, then return it.
+  ** If the page was not in the hash table and createFlag is 0, abort.
+  ** Otherwise (page not in hash and createFlag!=0) continue with
+  ** subsequent steps to try to create the page. */
+  if( pPage ){
+    if( PAGE_IS_UNPINNED(pPage) ){
+      return pcache1PinPage(pPage);
+    }else{
+      return pPage;
+    }
+  }else if( createFlag ){
+    /* Steps 3, 4, and 5 implemented by this subroutine */
+    return pcache1FetchStage2(pCache, iKey, createFlag);
+  }else{
+    return 0;
+  }
+}
+#if PCACHE1_MIGHT_USE_GROUP_MUTEX
+static PgHdr1 *pcache1FetchWithMutex(
+  sqlite3_pcache *p,
+  unsigned int iKey,
+  int createFlag
+){
+  PCache1 *pCache = (PCache1 *)p;
+  PgHdr1 *pPage;
+
+  pcache1EnterMutex(pCache->pGroup);
+  pPage = pcache1FetchNoMutex(p, iKey, createFlag);
+  assert( pPage==0 || pCache->iMaxKey>=iKey );
+  pcache1LeaveMutex(pCache->pGroup);
+  return pPage;
+}
+#endif
+static sqlite3_pcache_page *pcache1Fetch(
+  sqlite3_pcache *p,
+  unsigned int iKey,
+  int createFlag
+){
+#if PCACHE1_MIGHT_USE_GROUP_MUTEX || defined(SQLITE_DEBUG)
+  PCache1 *pCache = (PCache1 *)p;
+#endif
+
+  assert( offsetof(PgHdr1,page)==0 );
+  assert( pCache->bPurgeable || createFlag!=1 );
+  assert( pCache->bPurgeable || pCache->nMin==0 );
+  assert( pCache->bPurgeable==0 || pCache->nMin==10 );
+  assert( pCache->nMin==0 || pCache->bPurgeable );
+  assert( pCache->nHash>0 );
+#if PCACHE1_MIGHT_USE_GROUP_MUTEX
+  if( pCache->pGroup->mutex ){
+    return (sqlite3_pcache_page*)pcache1FetchWithMutex(p, iKey, createFlag);
+  }else
+#endif
+  {
+    return (sqlite3_pcache_page*)pcache1FetchNoMutex(p, iKey, createFlag);
+  }
+}
+
+
+/*
+** Implementation of the sqlite3_pcache.xUnpin method.
+**
+** Mark a page as unpinned (eligible for asynchronous recycling).
+*/
+static void pcache1Unpin(
+  sqlite3_pcache *p,
+  sqlite3_pcache_page *pPg,
+  int reuseUnlikely
+){
+  PCache1 *pCache = (PCache1 *)p;
+  PgHdr1 *pPage = (PgHdr1 *)pPg;
+  PGroup *pGroup = pCache->pGroup;
+
+  assert( pPage->pCache==pCache );
+  pcache1EnterMutex(pGroup);
+
+  /* It is an error to call this function if the page is already
+  ** part of the PGroup LRU list.
+  */
+  assert( pPage->pLruNext==0 );
+  assert( PAGE_IS_PINNED(pPage) );
+
+  if( reuseUnlikely || pGroup->nPurgeable>pGroup->nMaxPage ){
+    pcache1RemoveFromHash(pPage, 1);
+  }else{
+    /* Add the page to the PGroup LRU list. */
+    PgHdr1 **ppFirst = &pGroup->lru.pLruNext;
+    pPage->pLruPrev = &pGroup->lru;
+    (pPage->pLruNext = *ppFirst)->pLruPrev = pPage;
+    *ppFirst = pPage;
+    pCache->nRecyclable++;
+  }
+
+  pcache1LeaveMutex(pCache->pGroup);
+}
+
+/*
+** Implementation of the sqlite3_pcache.xRekey method.
+*/
+static void pcache1Rekey(
+  sqlite3_pcache *p,
+  sqlite3_pcache_page *pPg,
+  unsigned int iOld,
+  unsigned int iNew
+){
+  PCache1 *pCache = (PCache1 *)p;
+  PgHdr1 *pPage = (PgHdr1 *)pPg;
+  PgHdr1 **pp;
+  unsigned int hOld, hNew;
+  assert( pPage->iKey==iOld );
+  assert( pPage->pCache==pCache );
+  assert( iOld!=iNew );               /* The page number really is changing */
+
+  pcache1EnterMutex(pCache->pGroup);
+
+  assert( pcache1FetchNoMutex(p, iOld, 0)==pPage ); /* pPg really is iOld */
+  hOld = iOld%pCache->nHash;
+  pp = &pCache->apHash[hOld];
+  while( (*pp)!=pPage ){
+    pp = &(*pp)->pNext;
+  }
+  *pp = pPage->pNext;
+
+  assert( pcache1FetchNoMutex(p, iNew, 0)==0 ); /* iNew not in cache */
+  hNew = iNew%pCache->nHash;
+  pPage->iKey = iNew;
+  pPage->pNext = pCache->apHash[hNew];
+  pCache->apHash[hNew] = pPage;
+  if( iNew>pCache->iMaxKey ){
+    pCache->iMaxKey = iNew;
+  }
+
+  pcache1LeaveMutex(pCache->pGroup);
+}
+
+/*
+** Implementation of the sqlite3_pcache.xTruncate method.
+**
+** Discard all unpinned pages in the cache with a page number equal to
+** or greater than parameter iLimit. Any pinned pages with a page number
+** equal to or greater than iLimit are implicitly unpinned.
+*/
+static void pcache1Truncate(sqlite3_pcache *p, unsigned int iLimit){
+  PCache1 *pCache = (PCache1 *)p;
+  pcache1EnterMutex(pCache->pGroup);
+  if( iLimit<=pCache->iMaxKey ){
+    pcache1TruncateUnsafe(pCache, iLimit);
+    pCache->iMaxKey = iLimit-1;
+  }
+  pcache1LeaveMutex(pCache->pGroup);
+}
+
+/*
+** Implementation of the sqlite3_pcache.xDestroy method.
+**
+** Destroy a cache allocated using pcache1Create().
+*/
+static void pcache1Destroy(sqlite3_pcache *p){
+  PCache1 *pCache = (PCache1 *)p;
+  PGroup *pGroup = pCache->pGroup;
+  assert( pCache->bPurgeable || (pCache->nMax==0 && pCache->nMin==0) );
+  pcache1EnterMutex(pGroup);
+  if( pCache->nPage ) pcache1TruncateUnsafe(pCache, 0);
+  assert( pGroup->nMaxPage >= pCache->nMax );
+  pGroup->nMaxPage -= pCache->nMax;
+  assert( pGroup->nMinPage >= pCache->nMin );
+  pGroup->nMinPage -= pCache->nMin;
+  pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
+  pcache1EnforceMaxPage(pCache);
+  pcache1LeaveMutex(pGroup);
+  sqlite3_free(pCache->pBulk);
+  sqlite3_free(pCache->apHash);
+  sqlite3_free(pCache);
+}
+
+/*
+** This function is called during initialization (sqlite3_initialize()) to
+** install the default pluggable cache module, assuming the user has not
+** already provided an alternative.
+*/
+SQLITE_PRIVATE void sqlite3PCacheSetDefault(void){
+  static const sqlite3_pcache_methods2 defaultMethods = {
+    1,                       /* iVersion */
+    0,                       /* pArg */
+    pcache1Init,             /* xInit */
+    pcache1Shutdown,         /* xShutdown */
+    pcache1Create,           /* xCreate */
+    pcache1Cachesize,        /* xCachesize */
+    pcache1Pagecount,        /* xPagecount */
+    pcache1Fetch,            /* xFetch */
+    pcache1Unpin,            /* xUnpin */
+    pcache1Rekey,            /* xRekey */
+    pcache1Truncate,         /* xTruncate */
+    pcache1Destroy,          /* xDestroy */
+    pcache1Shrink            /* xShrink */
+  };
+  sqlite3_config(SQLITE_CONFIG_PCACHE2, &defaultMethods);
+}
+
+/*
+** Return the size of the header on each page of this PCACHE implementation.
+*/
+SQLITE_PRIVATE int sqlite3HeaderSizePcache1(void){ return ROUND8(sizeof(PgHdr1)); }
+
+/*
+** Return the global mutex used by this PCACHE implementation.  The
+** sqlite3_status() routine needs access to this mutex.
+*/
+SQLITE_PRIVATE sqlite3_mutex *sqlite3Pcache1Mutex(void){
+  return pcache1.mutex;
+}
+
+#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
+/*
+** This function is called to free superfluous dynamically allocated memory
+** held by the pager system. Memory in use by any SQLite pager allocated
+** by the current thread may be sqlite3_free()ed.
+**
+** nReq is the number of bytes of memory required. Once this much has
+** been released, the function returns. The return value is the total number
+** of bytes of memory released.
+*/
+SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int nReq){
+  int nFree = 0;
+  assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
+  assert( sqlite3_mutex_notheld(pcache1.mutex) );
+  if( sqlite3GlobalConfig.pPage==0 ){
+    PgHdr1 *p;
+    pcache1EnterMutex(&pcache1.grp);
+    while( (nReq<0 || nFree<nReq)
+       &&  (p=pcache1.grp.lru.pLruPrev)!=0
+       &&  p->isAnchor==0
+    ){
+      nFree += pcache1MemSize(p->page.pBuf);
+      assert( PAGE_IS_UNPINNED(p) );
+      pcache1PinPage(p);
+      pcache1RemoveFromHash(p, 1);
+    }
+    pcache1LeaveMutex(&pcache1.grp);
+  }
+  return nFree;
+}
+#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */
+
+#ifdef SQLITE_TEST
+/*
+** This function is used by test procedures to inspect the internal state
+** of the global cache.
+*/
+SQLITE_PRIVATE void sqlite3PcacheStats(
+  int *pnCurrent,      /* OUT: Total number of pages cached */
+  int *pnMax,          /* OUT: Global maximum cache size */
+  int *pnMin,          /* OUT: Sum of PCache1.nMin for purgeable caches */
+  int *pnRecyclable    /* OUT: Total number of pages available for recycling */
+){
+  PgHdr1 *p;
+  int nRecyclable = 0;
+  for(p=pcache1.grp.lru.pLruNext; p && !p->isAnchor; p=p->pLruNext){
+    assert( PAGE_IS_UNPINNED(p) );
+    nRecyclable++;
+  }
+  *pnCurrent = pcache1.grp.nPurgeable;
+  *pnMax = (int)pcache1.grp.nMaxPage;
+  *pnMin = (int)pcache1.grp.nMinPage;
+  *pnRecyclable = nRecyclable;
+}
+#endif
+
+/************** End of pcache1.c *********************************************/
+/************** Begin file rowset.c ******************************************/
+/*
+** 2008 December 3
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This module implements an object we call a "RowSet".
+**
+** The RowSet object is a collection of rowids.  Rowids
+** are inserted into the RowSet in an arbitrary order.  Inserts
+** can be intermixed with tests to see if a given rowid has been
+** previously inserted into the RowSet.
+**
+** After all inserts are finished, it is possible to extract the
+** elements of the RowSet in sorted order.  Once this extraction
+** process has started, no new elements may be inserted.
+**
+** Hence, the primitive operations for a RowSet are:
+**
+**    CREATE
+**    INSERT
+**    TEST
+**    SMALLEST
+**    DESTROY
+**
+** The CREATE and DESTROY primitives are the constructor and destructor,
+** obviously.  The INSERT primitive adds a new element to the RowSet.
+** TEST checks to see if an element is already in the RowSet.  SMALLEST
+** extracts the least value from the RowSet.
+**
+** The INSERT primitive might allocate additional memory.  Memory is
+** allocated in chunks so most INSERTs do no allocation.  There is an
+** upper bound on the size of allocated memory.  No memory is freed
+** until DESTROY.
+**
+** The TEST primitive includes a "batch" number.  The TEST primitive
+** will only see elements that were inserted before the last change
+** in the batch number.  In other words, if an INSERT occurs between
+** two TESTs where the TESTs have the same batch number, then the
+** value added by the INSERT will not be visible to the second TEST.
+** The initial batch number is zero, so if the very first TEST contains
+** a non-zero batch number, it will see all prior INSERTs.
+**
+** No INSERTs may occurs after a SMALLEST.  An assertion will fail if
+** that is attempted.
+**
+** The cost of an INSERT is roughly constant.  (Sometimes new memory
+** has to be allocated on an INSERT.)  The cost of a TEST with a new
+** batch number is O(NlogN) where N is the number of elements in the RowSet.
+** The cost of a TEST using the same batch number is O(logN).  The cost
+** of the first SMALLEST is O(NlogN).  Second and subsequent SMALLEST
+** primitives are constant time.  The cost of DESTROY is O(N).
+**
+** TEST and SMALLEST may not be used by the same RowSet.  This used to
+** be possible, but the feature was not used, so it was removed in order
+** to simplify the code.
+*/
+/* #include "sqliteInt.h" */
+
+
+/*
+** Target size for allocation chunks.
+*/
+#define ROWSET_ALLOCATION_SIZE 1024
+
+/*
+** The number of rowset entries per allocation chunk.
+*/
+#define ROWSET_ENTRY_PER_CHUNK  \
+                       ((ROWSET_ALLOCATION_SIZE-8)/sizeof(struct RowSetEntry))
+
+/*
+** Each entry in a RowSet is an instance of the following object.
+**
+** This same object is reused to store a linked list of trees of RowSetEntry
+** objects.  In that alternative use, pRight points to the next entry
+** in the list, pLeft points to the tree, and v is unused.  The
+** RowSet.pForest value points to the head of this forest list.
+*/
+struct RowSetEntry {
+  i64 v;                        /* ROWID value for this entry */
+  struct RowSetEntry *pRight;   /* Right subtree (larger entries) or list */
+  struct RowSetEntry *pLeft;    /* Left subtree (smaller entries) */
+};
+
+/*
+** RowSetEntry objects are allocated in large chunks (instances of the
+** following structure) to reduce memory allocation overhead.  The
+** chunks are kept on a linked list so that they can be deallocated
+** when the RowSet is destroyed.
+*/
+struct RowSetChunk {
+  struct RowSetChunk *pNextChunk;        /* Next chunk on list of them all */
+  struct RowSetEntry aEntry[ROWSET_ENTRY_PER_CHUNK]; /* Allocated entries */
+};
+
+/*
+** A RowSet in an instance of the following structure.
+**
+** A typedef of this structure if found in sqliteInt.h.
+*/
+struct RowSet {
+  struct RowSetChunk *pChunk;    /* List of all chunk allocations */
+  sqlite3 *db;                   /* The database connection */
+  struct RowSetEntry *pEntry;    /* List of entries using pRight */
+  struct RowSetEntry *pLast;     /* Last entry on the pEntry list */
+  struct RowSetEntry *pFresh;    /* Source of new entry objects */
+  struct RowSetEntry *pForest;   /* List of binary trees of entries */
+  u16 nFresh;                    /* Number of objects on pFresh */
+  u16 rsFlags;                   /* Various flags */
+  int iBatch;                    /* Current insert batch */
+};
+
+/*
+** Allowed values for RowSet.rsFlags
+*/
+#define ROWSET_SORTED  0x01   /* True if RowSet.pEntry is sorted */
+#define ROWSET_NEXT    0x02   /* True if sqlite3RowSetNext() has been called */
+
+/*
+** Allocate a RowSet object.  Return NULL if a memory allocation
+** error occurs.
+*/
+SQLITE_PRIVATE RowSet *sqlite3RowSetInit(sqlite3 *db){
+  RowSet *p = sqlite3DbMallocRawNN(db, sizeof(*p));
+  if( p ){
+    int N = sqlite3DbMallocSize(db, p);
+    p->pChunk = 0;
+    p->db = db;
+    p->pEntry = 0;
+    p->pLast = 0;
+    p->pForest = 0;
+    p->pFresh = (struct RowSetEntry*)(ROUND8(sizeof(*p)) + (char*)p);
+    p->nFresh = (u16)((N - ROUND8(sizeof(*p)))/sizeof(struct RowSetEntry));
+    p->rsFlags = ROWSET_SORTED;
+    p->iBatch = 0;
+  }
+  return p;
+}
+
+/*
+** Deallocate all chunks from a RowSet.  This frees all memory that
+** the RowSet has allocated over its lifetime.  This routine is
+** the destructor for the RowSet.
+*/
+SQLITE_PRIVATE void sqlite3RowSetClear(void *pArg){
+  RowSet *p = (RowSet*)pArg;
+  struct RowSetChunk *pChunk, *pNextChunk;
+  for(pChunk=p->pChunk; pChunk; pChunk = pNextChunk){
+    pNextChunk = pChunk->pNextChunk;
+    sqlite3DbFree(p->db, pChunk);
+  }
+  p->pChunk = 0;
+  p->nFresh = 0;
+  p->pEntry = 0;
+  p->pLast = 0;
+  p->pForest = 0;
+  p->rsFlags = ROWSET_SORTED;
+}
+
+/*
+** Deallocate all chunks from a RowSet.  This frees all memory that
+** the RowSet has allocated over its lifetime.  This routine is
+** the destructor for the RowSet.
+*/
+SQLITE_PRIVATE void sqlite3RowSetDelete(void *pArg){
+  sqlite3RowSetClear(pArg);
+  sqlite3DbFree(((RowSet*)pArg)->db, pArg);
+}
+
+/*
+** Allocate a new RowSetEntry object that is associated with the
+** given RowSet.  Return a pointer to the new and completely uninitialized
+** object.
+**
+** In an OOM situation, the RowSet.db->mallocFailed flag is set and this
+** routine returns NULL.
+*/
+static struct RowSetEntry *rowSetEntryAlloc(RowSet *p){
+  assert( p!=0 );
+  if( p->nFresh==0 ){  /*OPTIMIZATION-IF-FALSE*/
+    /* We could allocate a fresh RowSetEntry each time one is needed, but it
+    ** is more efficient to pull a preallocated entry from the pool */
+    struct RowSetChunk *pNew;
+    pNew = sqlite3DbMallocRawNN(p->db, sizeof(*pNew));
+    if( pNew==0 ){
+      return 0;
+    }
+    pNew->pNextChunk = p->pChunk;
+    p->pChunk = pNew;
+    p->pFresh = pNew->aEntry;
+    p->nFresh = ROWSET_ENTRY_PER_CHUNK;
+  }
+  p->nFresh--;
+  return p->pFresh++;
+}
+
+/*
+** Insert a new value into a RowSet.
+**
+** The mallocFailed flag of the database connection is set if a
+** memory allocation fails.
+*/
+SQLITE_PRIVATE void sqlite3RowSetInsert(RowSet *p, i64 rowid){
+  struct RowSetEntry *pEntry;  /* The new entry */
+  struct RowSetEntry *pLast;   /* The last prior entry */
+
+  /* This routine is never called after sqlite3RowSetNext() */
+  assert( p!=0 && (p->rsFlags & ROWSET_NEXT)==0 );
+
+  pEntry = rowSetEntryAlloc(p);
+  if( pEntry==0 ) return;
+  pEntry->v = rowid;
+  pEntry->pRight = 0;
+  pLast = p->pLast;
+  if( pLast ){
+    if( rowid<=pLast->v ){  /*OPTIMIZATION-IF-FALSE*/
+      /* Avoid unnecessary sorts by preserving the ROWSET_SORTED flags
+      ** where possible */
+      p->rsFlags &= ~ROWSET_SORTED;
+    }
+    pLast->pRight = pEntry;
+  }else{
+    p->pEntry = pEntry;
+  }
+  p->pLast = pEntry;
+}
+
+/*
+** Merge two lists of RowSetEntry objects.  Remove duplicates.
+**
+** The input lists are connected via pRight pointers and are
+** assumed to each already be in sorted order.
+*/
+static struct RowSetEntry *rowSetEntryMerge(
+  struct RowSetEntry *pA,    /* First sorted list to be merged */
+  struct RowSetEntry *pB     /* Second sorted list to be merged */
+){
+  struct RowSetEntry head;
+  struct RowSetEntry *pTail;
+
+  pTail = &head;
+  assert( pA!=0 && pB!=0 );
+  for(;;){
+    assert( pA->pRight==0 || pA->v<=pA->pRight->v );
+    assert( pB->pRight==0 || pB->v<=pB->pRight->v );
+    if( pA->v<=pB->v ){
+      if( pA->v<pB->v ) pTail = pTail->pRight = pA;
+      pA = pA->pRight;
+      if( pA==0 ){
+        pTail->pRight = pB;
+        break;
+      }
+    }else{
+      pTail = pTail->pRight = pB;
+      pB = pB->pRight;
+      if( pB==0 ){
+        pTail->pRight = pA;
+        break;
+      }
+    }
+  }
+  return head.pRight;
+}
+
+/*
+** Sort all elements on the list of RowSetEntry objects into order of
+** increasing v.
+*/
+static struct RowSetEntry *rowSetEntrySort(struct RowSetEntry *pIn){
+  unsigned int i;
+  struct RowSetEntry *pNext, *aBucket[40];
+
+  memset(aBucket, 0, sizeof(aBucket));
+  while( pIn ){
+    pNext = pIn->pRight;
+    pIn->pRight = 0;
+    for(i=0; aBucket[i]; i++){
+      pIn = rowSetEntryMerge(aBucket[i], pIn);
+      aBucket[i] = 0;
+    }
+    aBucket[i] = pIn;
+    pIn = pNext;
+  }
+  pIn = aBucket[0];
+  for(i=1; i<sizeof(aBucket)/sizeof(aBucket[0]); i++){
+    if( aBucket[i]==0 ) continue;
+    pIn = pIn ? rowSetEntryMerge(pIn, aBucket[i]) : aBucket[i];
+  }
+  return pIn;
+}
+
+
+/*
+** The input, pIn, is a binary tree (or subtree) of RowSetEntry objects.
+** Convert this tree into a linked list connected by the pRight pointers
+** and return pointers to the first and last elements of the new list.
+*/
+static void rowSetTreeToList(
+  struct RowSetEntry *pIn,         /* Root of the input tree */
+  struct RowSetEntry **ppFirst,    /* Write head of the output list here */
+  struct RowSetEntry **ppLast      /* Write tail of the output list here */
+){
+  assert( pIn!=0 );
+  if( pIn->pLeft ){
+    struct RowSetEntry *p;
+    rowSetTreeToList(pIn->pLeft, ppFirst, &p);
+    p->pRight = pIn;
+  }else{
+    *ppFirst = pIn;
+  }
+  if( pIn->pRight ){
+    rowSetTreeToList(pIn->pRight, &pIn->pRight, ppLast);
+  }else{
+    *ppLast = pIn;
+  }
+  assert( (*ppLast)->pRight==0 );
+}
+
+
+/*
+** Convert a sorted list of elements (connected by pRight) into a binary
+** tree with depth of iDepth.  A depth of 1 means the tree contains a single
+** node taken from the head of *ppList.  A depth of 2 means a tree with
+** three nodes.  And so forth.
+**
+** Use as many entries from the input list as required and update the
+** *ppList to point to the unused elements of the list.  If the input
+** list contains too few elements, then construct an incomplete tree
+** and leave *ppList set to NULL.
+**
+** Return a pointer to the root of the constructed binary tree.
+*/
+static struct RowSetEntry *rowSetNDeepTree(
+  struct RowSetEntry **ppList,
+  int iDepth
+){
+  struct RowSetEntry *p;         /* Root of the new tree */
+  struct RowSetEntry *pLeft;     /* Left subtree */
+  if( *ppList==0 ){ /*OPTIMIZATION-IF-TRUE*/
+    /* Prevent unnecessary deep recursion when we run out of entries */
+    return 0;
+  }
+  if( iDepth>1 ){   /*OPTIMIZATION-IF-TRUE*/
+    /* This branch causes a *balanced* tree to be generated.  A valid tree
+    ** is still generated without this branch, but the tree is wildly
+    ** unbalanced and inefficient. */
+    pLeft = rowSetNDeepTree(ppList, iDepth-1);
+    p = *ppList;
+    if( p==0 ){     /*OPTIMIZATION-IF-FALSE*/
+      /* It is safe to always return here, but the resulting tree
+      ** would be unbalanced */
+      return pLeft;
+    }
+    p->pLeft = pLeft;
+    *ppList = p->pRight;
+    p->pRight = rowSetNDeepTree(ppList, iDepth-1);
+  }else{
+    p = *ppList;
+    *ppList = p->pRight;
+    p->pLeft = p->pRight = 0;
+  }
+  return p;
+}
+
+/*
+** Convert a sorted list of elements into a binary tree. Make the tree
+** as deep as it needs to be in order to contain the entire list.
+*/
+static struct RowSetEntry *rowSetListToTree(struct RowSetEntry *pList){
+  int iDepth;           /* Depth of the tree so far */
+  struct RowSetEntry *p;       /* Current tree root */
+  struct RowSetEntry *pLeft;   /* Left subtree */
+
+  assert( pList!=0 );
+  p = pList;
+  pList = p->pRight;
+  p->pLeft = p->pRight = 0;
+  for(iDepth=1; pList; iDepth++){
+    pLeft = p;
+    p = pList;
+    pList = p->pRight;
+    p->pLeft = pLeft;
+    p->pRight = rowSetNDeepTree(&pList, iDepth);
+  }
+  return p;
+}
+
+/*
+** Extract the smallest element from the RowSet.
+** Write the element into *pRowid.  Return 1 on success.  Return
+** 0 if the RowSet is already empty.
+**
+** After this routine has been called, the sqlite3RowSetInsert()
+** routine may not be called again.
+**
+** This routine may not be called after sqlite3RowSetTest() has
+** been used.  Older versions of RowSet allowed that, but as the
+** capability was not used by the code generator, it was removed
+** for code economy.
+*/
+SQLITE_PRIVATE int sqlite3RowSetNext(RowSet *p, i64 *pRowid){
+  assert( p!=0 );
+  assert( p->pForest==0 );  /* Cannot be used with sqlite3RowSetText() */
+
+  /* Merge the forest into a single sorted list on first call */
+  if( (p->rsFlags & ROWSET_NEXT)==0 ){  /*OPTIMIZATION-IF-FALSE*/
+    if( (p->rsFlags & ROWSET_SORTED)==0 ){  /*OPTIMIZATION-IF-FALSE*/
+      p->pEntry = rowSetEntrySort(p->pEntry);
+    }
+    p->rsFlags |= ROWSET_SORTED|ROWSET_NEXT;
+  }
+
+  /* Return the next entry on the list */
+  if( p->pEntry ){
+    *pRowid = p->pEntry->v;
+    p->pEntry = p->pEntry->pRight;
+    if( p->pEntry==0 ){ /*OPTIMIZATION-IF-TRUE*/
+      /* Free memory immediately, rather than waiting on sqlite3_finalize() */
+      sqlite3RowSetClear(p);
+    }
+    return 1;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Check to see if element iRowid was inserted into the rowset as
+** part of any insert batch prior to iBatch.  Return 1 or 0.
+**
+** If this is the first test of a new batch and if there exist entries
+** on pRowSet->pEntry, then sort those entries into the forest at
+** pRowSet->pForest so that they can be tested.
+*/
+SQLITE_PRIVATE int sqlite3RowSetTest(RowSet *pRowSet, int iBatch, sqlite3_int64 iRowid){
+  struct RowSetEntry *p, *pTree;
+
+  /* This routine is never called after sqlite3RowSetNext() */
+  assert( pRowSet!=0 && (pRowSet->rsFlags & ROWSET_NEXT)==0 );
+
+  /* Sort entries into the forest on the first test of a new batch.
+  ** To save unnecessary work, only do this when the batch number changes.
+  */
+  if( iBatch!=pRowSet->iBatch ){  /*OPTIMIZATION-IF-FALSE*/
+    p = pRowSet->pEntry;
+    if( p ){
+      struct RowSetEntry **ppPrevTree = &pRowSet->pForest;
+      if( (pRowSet->rsFlags & ROWSET_SORTED)==0 ){ /*OPTIMIZATION-IF-FALSE*/
+        /* Only sort the current set of entries if they need it */
+        p = rowSetEntrySort(p);
+      }
+      for(pTree = pRowSet->pForest; pTree; pTree=pTree->pRight){
+        ppPrevTree = &pTree->pRight;
+        if( pTree->pLeft==0 ){
+          pTree->pLeft = rowSetListToTree(p);
+          break;
+        }else{
+          struct RowSetEntry *pAux, *pTail;
+          rowSetTreeToList(pTree->pLeft, &pAux, &pTail);
+          pTree->pLeft = 0;
+          p = rowSetEntryMerge(pAux, p);
+        }
+      }
+      if( pTree==0 ){
+        *ppPrevTree = pTree = rowSetEntryAlloc(pRowSet);
+        if( pTree ){
+          pTree->v = 0;
+          pTree->pRight = 0;
+          pTree->pLeft = rowSetListToTree(p);
+        }
+      }
+      pRowSet->pEntry = 0;
+      pRowSet->pLast = 0;
+      pRowSet->rsFlags |= ROWSET_SORTED;
+    }
+    pRowSet->iBatch = iBatch;
+  }
+
+  /* Test to see if the iRowid value appears anywhere in the forest.
+  ** Return 1 if it does and 0 if not.
+  */
+  for(pTree = pRowSet->pForest; pTree; pTree=pTree->pRight){
+    p = pTree->pLeft;
+    while( p ){
+      if( p->v<iRowid ){
+        p = p->pRight;
+      }else if( p->v>iRowid ){
+        p = p->pLeft;
+      }else{
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+/************** End of rowset.c **********************************************/
+/************** Begin file pager.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the implementation of the page cache subsystem or "pager".
+**
+** The pager is used to access a database disk file.  It implements
+** atomic commit and rollback through the use of a journal file that
+** is separate from the database file.  The pager also implements file
+** locking to prevent two processes from writing the same database
+** file simultaneously, or one process from reading the database while
+** another is writing.
+*/
+#ifndef SQLITE_OMIT_DISKIO
+/* #include "sqliteInt.h" */
+/************** Include wal.h in the middle of pager.c ***********************/
+/************** Begin file wal.h *********************************************/
+/*
+** 2010 February 1
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface to the write-ahead logging
+** system. Refer to the comments below and the header comment attached to
+** the implementation of each function in log.c for further details.
+*/
+
+#ifndef SQLITE_WAL_H
+#define SQLITE_WAL_H
+
+/* #include "sqliteInt.h" */
+
+/* Macros for extracting appropriate sync flags for either transaction
+** commits (WAL_SYNC_FLAGS(X)) or for checkpoint ops (CKPT_SYNC_FLAGS(X)):
+*/
+#define WAL_SYNC_FLAGS(X)   ((X)&0x03)
+#define CKPT_SYNC_FLAGS(X)  (((X)>>2)&0x03)
+
+#ifdef SQLITE_OMIT_WAL
+# define sqlite3WalOpen(x,y,z)                   0
+# define sqlite3WalLimit(x,y)
+# define sqlite3WalClose(v,w,x,y,z)              0
+# define sqlite3WalBeginReadTransaction(y,z)     0
+# define sqlite3WalEndReadTransaction(z)
+# define sqlite3WalDbsize(y)                     0
+# define sqlite3WalBeginWriteTransaction(y)      0
+# define sqlite3WalEndWriteTransaction(x)        0
+# define sqlite3WalUndo(x,y,z)                   0
+# define sqlite3WalSavepoint(y,z)
+# define sqlite3WalSavepointUndo(y,z)            0
+# define sqlite3WalFrames(u,v,w,x,y,z)           0
+# define sqlite3WalCheckpoint(q,r,s,t,u,v,w,x,y,z) 0
+# define sqlite3WalCallback(z)                   0
+# define sqlite3WalExclusiveMode(y,z)            0
+# define sqlite3WalHeapMemory(z)                 0
+# define sqlite3WalFramesize(z)                  0
+# define sqlite3WalFindFrame(x,y,z)              0
+# define sqlite3WalFile(x)                       0
+# undef SQLITE_USE_SEH
+#else
+
+#define WAL_SAVEPOINT_NDATA 4
+
+/* Connection to a write-ahead log (WAL) file.
+** There is one object of this type for each pager.
+*/
+typedef struct Wal Wal;
+
+/* Open and close a connection to a write-ahead log. */
+SQLITE_PRIVATE int sqlite3WalOpen(sqlite3_vfs*, sqlite3_file*, const char *, int, i64, Wal**);
+SQLITE_PRIVATE int sqlite3WalClose(Wal *pWal, sqlite3*, int sync_flags, int, u8 *);
+
+/* Set the limiting size of a WAL file. */
+SQLITE_PRIVATE void sqlite3WalLimit(Wal*, i64);
+
+/* Used by readers to open (lock) and close (unlock) a snapshot.  A
+** snapshot is like a read-transaction.  It is the state of the database
+** at an instant in time.  sqlite3WalOpenSnapshot gets a read lock and
+** preserves the current state even if the other threads or processes
+** write to or checkpoint the WAL.  sqlite3WalCloseSnapshot() closes the
+** transaction and releases the lock.
+*/
+SQLITE_PRIVATE int sqlite3WalBeginReadTransaction(Wal *pWal, int *);
+SQLITE_PRIVATE void sqlite3WalEndReadTransaction(Wal *pWal);
+
+/* Read a page from the write-ahead log, if it is present. */
+SQLITE_PRIVATE int sqlite3WalFindFrame(Wal *, Pgno, u32 *);
+SQLITE_PRIVATE int sqlite3WalReadFrame(Wal *, u32, int, u8 *);
+
+/* If the WAL is not empty, return the size of the database. */
+SQLITE_PRIVATE Pgno sqlite3WalDbsize(Wal *pWal);
+
+/* Obtain or release the WRITER lock. */
+SQLITE_PRIVATE int sqlite3WalBeginWriteTransaction(Wal *pWal);
+SQLITE_PRIVATE int sqlite3WalEndWriteTransaction(Wal *pWal);
+
+/* Undo any frames written (but not committed) to the log */
+SQLITE_PRIVATE int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx);
+
+/* Return an integer that records the current (uncommitted) write
+** position in the WAL */
+SQLITE_PRIVATE void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData);
+
+/* Move the write position of the WAL back to iFrame.  Called in
+** response to a ROLLBACK TO command. */
+SQLITE_PRIVATE int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData);
+
+/* Write a frame or frames to the log. */
+SQLITE_PRIVATE int sqlite3WalFrames(Wal *pWal, int, PgHdr *, Pgno, int, int);
+
+/* Copy pages from the log to the database file */
+SQLITE_PRIVATE int sqlite3WalCheckpoint(
+  Wal *pWal,                      /* Write-ahead log connection */
+  sqlite3 *db,                    /* Check this handle's interrupt flag */
+  int eMode,                      /* One of PASSIVE, FULL and RESTART */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags to sync db file with (or 0) */
+  int nBuf,                       /* Size of buffer nBuf */
+  u8 *zBuf,                       /* Temporary buffer to use */
+  int *pnLog,                     /* OUT: Number of frames in WAL */
+  int *pnCkpt                     /* OUT: Number of backfilled frames in WAL */
+);
+
+/* Return the value to pass to a sqlite3_wal_hook callback, the
+** number of frames in the WAL at the point of the last commit since
+** sqlite3WalCallback() was called.  If no commits have occurred since
+** the last call, then return 0.
+*/
+SQLITE_PRIVATE int sqlite3WalCallback(Wal *pWal);
+
+/* Tell the wal layer that an EXCLUSIVE lock has been obtained (or released)
+** by the pager layer on the database file.
+*/
+SQLITE_PRIVATE int sqlite3WalExclusiveMode(Wal *pWal, int op);
+
+/* Return true if the argument is non-NULL and the WAL module is using
+** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
+** WAL module is using shared-memory, return false.
+*/
+SQLITE_PRIVATE int sqlite3WalHeapMemory(Wal *pWal);
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+SQLITE_PRIVATE int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot);
+SQLITE_PRIVATE void sqlite3WalSnapshotOpen(Wal *pWal, sqlite3_snapshot *pSnapshot);
+SQLITE_PRIVATE int sqlite3WalSnapshotRecover(Wal *pWal);
+SQLITE_PRIVATE int sqlite3WalSnapshotCheck(Wal *pWal, sqlite3_snapshot *pSnapshot);
+SQLITE_PRIVATE void sqlite3WalSnapshotUnlock(Wal *pWal);
+#endif
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/* If the WAL file is not empty, return the number of bytes of content
+** stored in each frame (i.e. the db page-size when the WAL was created).
+*/
+SQLITE_PRIVATE int sqlite3WalFramesize(Wal *pWal);
+#endif
+
+/* Return the sqlite3_file object for the WAL file */
+SQLITE_PRIVATE sqlite3_file *sqlite3WalFile(Wal *pWal);
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+SQLITE_PRIVATE int sqlite3WalWriteLock(Wal *pWal, int bLock);
+SQLITE_PRIVATE void sqlite3WalDb(Wal *pWal, sqlite3 *db);
+#endif
+
+#ifdef SQLITE_USE_SEH
+SQLITE_PRIVATE int sqlite3WalSystemErrno(Wal*);
+#endif
+
+#endif /* ifndef SQLITE_OMIT_WAL */
+#endif /* SQLITE_WAL_H */
+
+/************** End of wal.h *************************************************/
+/************** Continuing where we left off in pager.c **********************/
+
+
+/******************* NOTES ON THE DESIGN OF THE PAGER ************************
+**
+** This comment block describes invariants that hold when using a rollback
+** journal.  These invariants do not apply for journal_mode=WAL,
+** journal_mode=MEMORY, or journal_mode=OFF.
+**
+** Within this comment block, a page is deemed to have been synced
+** automatically as soon as it is written when PRAGMA synchronous=OFF.
+** Otherwise, the page is not synced until the xSync method of the VFS
+** is called successfully on the file containing the page.
+**
+** Definition:  A page of the database file is said to be "overwriteable" if
+** one or more of the following are true about the page:
+**
+**     (a)  The original content of the page as it was at the beginning of
+**          the transaction has been written into the rollback journal and
+**          synced.
+**
+**     (b)  The page was a freelist leaf page at the start of the transaction.
+**
+**     (c)  The page number is greater than the largest page that existed in
+**          the database file at the start of the transaction.
+**
+** (1) A page of the database file is never overwritten unless one of the
+**     following are true:
+**
+**     (a) The page and all other pages on the same sector are overwriteable.
+**
+**     (b) The atomic page write optimization is enabled, and the entire
+**         transaction other than the update of the transaction sequence
+**         number consists of a single page change.
+**
+** (2) The content of a page written into the rollback journal exactly matches
+**     both the content in the database when the rollback journal was written
+**     and the content in the database at the beginning of the current
+**     transaction.
+**
+** (3) Writes to the database file are an integer multiple of the page size
+**     in length and are aligned on a page boundary.
+**
+** (4) Reads from the database file are either aligned on a page boundary and
+**     an integer multiple of the page size in length or are taken from the
+**     first 100 bytes of the database file.
+**
+** (5) All writes to the database file are synced prior to the rollback journal
+**     being deleted, truncated, or zeroed.
+**
+** (6) If a super-journal file is used, then all writes to the database file
+**     are synced prior to the super-journal being deleted.
+**
+** Definition: Two databases (or the same database at two points it time)
+** are said to be "logically equivalent" if they give the same answer to
+** all queries.  Note in particular the content of freelist leaf
+** pages can be changed arbitrarily without affecting the logical equivalence
+** of the database.
+**
+** (7) At any time, if any subset, including the empty set and the total set,
+**     of the unsynced changes to a rollback journal are removed and the
+**     journal is rolled back, the resulting database file will be logically
+**     equivalent to the database file at the beginning of the transaction.
+**
+** (8) When a transaction is rolled back, the xTruncate method of the VFS
+**     is called to restore the database file to the same size it was at
+**     the beginning of the transaction.  (In some VFSes, the xTruncate
+**     method is a no-op, but that does not change the fact the SQLite will
+**     invoke it.)
+**
+** (9) Whenever the database file is modified, at least one bit in the range
+**     of bytes from 24 through 39 inclusive will be changed prior to releasing
+**     the EXCLUSIVE lock, thus signaling other connections on the same
+**     database to flush their caches.
+**
+** (10) The pattern of bits in bytes 24 through 39 shall not repeat in less
+**      than one billion transactions.
+**
+** (11) A database file is well-formed at the beginning and at the conclusion
+**      of every transaction.
+**
+** (12) An EXCLUSIVE lock is held on the database file when writing to
+**      the database file.
+**
+** (13) A SHARED lock is held on the database file while reading any
+**      content out of the database file.
+**
+******************************************************************************/
+
+/*
+** Macros for troubleshooting.  Normally turned off
+*/
+#if 0
+int sqlite3PagerTrace=1;  /* True to enable tracing */
+#define sqlite3DebugPrintf printf
+#define PAGERTRACE(X)     if( sqlite3PagerTrace ){ sqlite3DebugPrintf X; }
+#else
+#define PAGERTRACE(X)
+#endif
+
+/*
+** The following two macros are used within the PAGERTRACE() macros above
+** to print out file-descriptors.
+**
+** PAGERID() takes a pointer to a Pager struct as its argument. The
+** associated file-descriptor is returned. FILEHANDLEID() takes an sqlite3_file
+** struct as its argument.
+*/
+#define PAGERID(p) (SQLITE_PTR_TO_INT(p->fd))
+#define FILEHANDLEID(fd) (SQLITE_PTR_TO_INT(fd))
+
+/*
+** The Pager.eState variable stores the current 'state' of a pager. A
+** pager may be in any one of the seven states shown in the following
+** state diagram.
+**
+**                            OPEN <------+------+
+**                              |         |      |
+**                              V         |      |
+**               +---------> READER-------+      |
+**               |              |                |
+**               |              V                |
+**               |<-------WRITER_LOCKED------> ERROR
+**               |              |                ^
+**               |              V                |
+**               |<------WRITER_CACHEMOD-------->|
+**               |              |                |
+**               |              V                |
+**               |<-------WRITER_DBMOD---------->|
+**               |              |                |
+**               |              V                |
+**               +<------WRITER_FINISHED-------->+
+**
+**
+** List of state transitions and the C [function] that performs each:
+**
+**   OPEN              -> READER              [sqlite3PagerSharedLock]
+**   READER            -> OPEN                [pager_unlock]
+**
+**   READER            -> WRITER_LOCKED       [sqlite3PagerBegin]
+**   WRITER_LOCKED     -> WRITER_CACHEMOD     [pager_open_journal]
+**   WRITER_CACHEMOD   -> WRITER_DBMOD        [syncJournal]
+**   WRITER_DBMOD      -> WRITER_FINISHED     [sqlite3PagerCommitPhaseOne]
+**   WRITER_***        -> READER              [pager_end_transaction]
+**
+**   WRITER_***        -> ERROR               [pager_error]
+**   ERROR             -> OPEN                [pager_unlock]
+**
+**
+**  OPEN:
+**
+**    The pager starts up in this state. Nothing is guaranteed in this
+**    state - the file may or may not be locked and the database size is
+**    unknown. The database may not be read or written.
+**
+**    * No read or write transaction is active.
+**    * Any lock, or no lock at all, may be held on the database file.
+**    * The dbSize, dbOrigSize and dbFileSize variables may not be trusted.
+**
+**  READER:
+**
+**    In this state all the requirements for reading the database in
+**    rollback (non-WAL) mode are met. Unless the pager is (or recently
+**    was) in exclusive-locking mode, a user-level read transaction is
+**    open. The database size is known in this state.
+**
+**    A connection running with locking_mode=normal enters this state when
+**    it opens a read-transaction on the database and returns to state
+**    OPEN after the read-transaction is completed. However a connection
+**    running in locking_mode=exclusive (including temp databases) remains in
+**    this state even after the read-transaction is closed. The only way
+**    a locking_mode=exclusive connection can transition from READER to OPEN
+**    is via the ERROR state (see below).
+**
+**    * A read transaction may be active (but a write-transaction cannot).
+**    * A SHARED or greater lock is held on the database file.
+**    * The dbSize variable may be trusted (even if a user-level read
+**      transaction is not active). The dbOrigSize and dbFileSize variables
+**      may not be trusted at this point.
+**    * If the database is a WAL database, then the WAL connection is open.
+**    * Even if a read-transaction is not open, it is guaranteed that
+**      there is no hot-journal in the file-system.
+**
+**  WRITER_LOCKED:
+**
+**    The pager moves to this state from READER when a write-transaction
+**    is first opened on the database. In WRITER_LOCKED state, all locks
+**    required to start a write-transaction are held, but no actual
+**    modifications to the cache or database have taken place.
+**
+**    In rollback mode, a RESERVED or (if the transaction was opened with
+**    BEGIN EXCLUSIVE) EXCLUSIVE lock is obtained on the database file when
+**    moving to this state, but the journal file is not written to or opened
+**    to in this state. If the transaction is committed or rolled back while
+**    in WRITER_LOCKED state, all that is required is to unlock the database
+**    file.
+**
+**    IN WAL mode, WalBeginWriteTransaction() is called to lock the log file.
+**    If the connection is running with locking_mode=exclusive, an attempt
+**    is made to obtain an EXCLUSIVE lock on the database file.
+**
+**    * A write transaction is active.
+**    * If the connection is open in rollback-mode, a RESERVED or greater
+**      lock is held on the database file.
+**    * If the connection is open in WAL-mode, a WAL write transaction
+**      is open (i.e. sqlite3WalBeginWriteTransaction() has been successfully
+**      called).
+**    * The dbSize, dbOrigSize and dbFileSize variables are all valid.
+**    * The contents of the pager cache have not been modified.
+**    * The journal file may or may not be open.
+**    * Nothing (not even the first header) has been written to the journal.
+**
+**  WRITER_CACHEMOD:
+**
+**    A pager moves from WRITER_LOCKED state to this state when a page is
+**    first modified by the upper layer. In rollback mode the journal file
+**    is opened (if it is not already open) and a header written to the
+**    start of it. The database file on disk has not been modified.
+**
+**    * A write transaction is active.
+**    * A RESERVED or greater lock is held on the database file.
+**    * The journal file is open and the first header has been written
+**      to it, but the header has not been synced to disk.
+**    * The contents of the page cache have been modified.
+**
+**  WRITER_DBMOD:
+**
+**    The pager transitions from WRITER_CACHEMOD into WRITER_DBMOD state
+**    when it modifies the contents of the database file. WAL connections
+**    never enter this state (since they do not modify the database file,
+**    just the log file).
+**
+**    * A write transaction is active.
+**    * An EXCLUSIVE or greater lock is held on the database file.
+**    * The journal file is open and the first header has been written
+**      and synced to disk.
+**    * The contents of the page cache have been modified (and possibly
+**      written to disk).
+**
+**  WRITER_FINISHED:
+**
+**    It is not possible for a WAL connection to enter this state.
+**
+**    A rollback-mode pager changes to WRITER_FINISHED state from WRITER_DBMOD
+**    state after the entire transaction has been successfully written into the
+**    database file. In this state the transaction may be committed simply
+**    by finalizing the journal file. Once in WRITER_FINISHED state, it is
+**    not possible to modify the database further. At this point, the upper
+**    layer must either commit or rollback the transaction.
+**
+**    * A write transaction is active.
+**    * An EXCLUSIVE or greater lock is held on the database file.
+**    * All writing and syncing of journal and database data has finished.
+**      If no error occurred, all that remains is to finalize the journal to
+**      commit the transaction. If an error did occur, the caller will need
+**      to rollback the transaction.
+**
+**  ERROR:
+**
+**    The ERROR state is entered when an IO or disk-full error (including
+**    SQLITE_IOERR_NOMEM) occurs at a point in the code that makes it
+**    difficult to be sure that the in-memory pager state (cache contents,
+**    db size etc.) are consistent with the contents of the file-system.
+**
+**    Temporary pager files may enter the ERROR state, but in-memory pagers
+**    cannot.
+**
+**    For example, if an IO error occurs while performing a rollback,
+**    the contents of the page-cache may be left in an inconsistent state.
+**    At this point it would be dangerous to change back to READER state
+**    (as usually happens after a rollback). Any subsequent readers might
+**    report database corruption (due to the inconsistent cache), and if
+**    they upgrade to writers, they may inadvertently corrupt the database
+**    file. To avoid this hazard, the pager switches into the ERROR state
+**    instead of READER following such an error.
+**
+**    Once it has entered the ERROR state, any attempt to use the pager
+**    to read or write data returns an error. Eventually, once all
+**    outstanding transactions have been abandoned, the pager is able to
+**    transition back to OPEN state, discarding the contents of the
+**    page-cache and any other in-memory state at the same time. Everything
+**    is reloaded from disk (and, if necessary, hot-journal rollback performed)
+**    when a read-transaction is next opened on the pager (transitioning
+**    the pager into READER state). At that point the system has recovered
+**    from the error.
+**
+**    Specifically, the pager jumps into the ERROR state if:
+**
+**      1. An error occurs while attempting a rollback. This happens in
+**         function sqlite3PagerRollback().
+**
+**      2. An error occurs while attempting to finalize a journal file
+**         following a commit in function sqlite3PagerCommitPhaseTwo().
+**
+**      3. An error occurs while attempting to write to the journal or
+**         database file in function pagerStress() in order to free up
+**         memory.
+**
+**    In other cases, the error is returned to the b-tree layer. The b-tree
+**    layer then attempts a rollback operation. If the error condition
+**    persists, the pager enters the ERROR state via condition (1) above.
+**
+**    Condition (3) is necessary because it can be triggered by a read-only
+**    statement executed within a transaction. In this case, if the error
+**    code were simply returned to the user, the b-tree layer would not
+**    automatically attempt a rollback, as it assumes that an error in a
+**    read-only statement cannot leave the pager in an internally inconsistent
+**    state.
+**
+**    * The Pager.errCode variable is set to something other than SQLITE_OK.
+**    * There are one or more outstanding references to pages (after the
+**      last reference is dropped the pager should move back to OPEN state).
+**    * The pager is not an in-memory pager.
+**
+**
+** Notes:
+**
+**   * A pager is never in WRITER_DBMOD or WRITER_FINISHED state if the
+**     connection is open in WAL mode. A WAL connection is always in one
+**     of the first four states.
+**
+**   * Normally, a connection open in exclusive mode is never in PAGER_OPEN
+**     state. There are two exceptions: immediately after exclusive-mode has
+**     been turned on (and before any read or write transactions are
+**     executed), and when the pager is leaving the "error state".
+**
+**   * See also: assert_pager_state().
+*/
+#define PAGER_OPEN                  0
+#define PAGER_READER                1
+#define PAGER_WRITER_LOCKED         2
+#define PAGER_WRITER_CACHEMOD       3
+#define PAGER_WRITER_DBMOD          4
+#define PAGER_WRITER_FINISHED       5
+#define PAGER_ERROR                 6
+
+/*
+** The Pager.eLock variable is almost always set to one of the
+** following locking-states, according to the lock currently held on
+** the database file: NO_LOCK, SHARED_LOCK, RESERVED_LOCK or EXCLUSIVE_LOCK.
+** This variable is kept up to date as locks are taken and released by
+** the pagerLockDb() and pagerUnlockDb() wrappers.
+**
+** If the VFS xLock() or xUnlock() returns an error other than SQLITE_BUSY
+** (i.e. one of the SQLITE_IOERR subtypes), it is not clear whether or not
+** the operation was successful. In these circumstances pagerLockDb() and
+** pagerUnlockDb() take a conservative approach - eLock is always updated
+** when unlocking the file, and only updated when locking the file if the
+** VFS call is successful. This way, the Pager.eLock variable may be set
+** to a less exclusive (lower) value than the lock that is actually held
+** at the system level, but it is never set to a more exclusive value.
+**
+** This is usually safe. If an xUnlock fails or appears to fail, there may
+** be a few redundant xLock() calls or a lock may be held for longer than
+** required, but nothing really goes wrong.
+**
+** The exception is when the database file is unlocked as the pager moves
+** from ERROR to OPEN state. At this point there may be a hot-journal file
+** in the file-system that needs to be rolled back (as part of an OPEN->SHARED
+** transition, by the same pager or any other). If the call to xUnlock()
+** fails at this point and the pager is left holding an EXCLUSIVE lock, this
+** can confuse the call to xCheckReservedLock() call made later as part
+** of hot-journal detection.
+**
+** xCheckReservedLock() is defined as returning true "if there is a RESERVED
+** lock held by this process or any others". So xCheckReservedLock may
+** return true because the caller itself is holding an EXCLUSIVE lock (but
+** doesn't know it because of a previous error in xUnlock). If this happens
+** a hot-journal may be mistaken for a journal being created by an active
+** transaction in another process, causing SQLite to read from the database
+** without rolling it back.
+**
+** To work around this, if a call to xUnlock() fails when unlocking the
+** database in the ERROR state, Pager.eLock is set to UNKNOWN_LOCK. It
+** is only changed back to a real locking state after a successful call
+** to xLock(EXCLUSIVE). Also, the code to do the OPEN->SHARED state transition
+** omits the check for a hot-journal if Pager.eLock is set to UNKNOWN_LOCK
+** lock. Instead, it assumes a hot-journal exists and obtains an EXCLUSIVE
+** lock on the database file before attempting to roll it back. See function
+** PagerSharedLock() for more detail.
+**
+** Pager.eLock may only be set to UNKNOWN_LOCK when the pager is in
+** PAGER_OPEN state.
+*/
+#define UNKNOWN_LOCK                (EXCLUSIVE_LOCK+1)
+
+/*
+** The maximum allowed sector size. 64KiB. If the xSectorsize() method
+** returns a value larger than this, then MAX_SECTOR_SIZE is used instead.
+** This could conceivably cause corruption following a power failure on
+** such a system. This is currently an undocumented limit.
+*/
+#define MAX_SECTOR_SIZE 0x10000
+
+
+/*
+** An instance of the following structure is allocated for each active
+** savepoint and statement transaction in the system. All such structures
+** are stored in the Pager.aSavepoint[] array, which is allocated and
+** resized using sqlite3Realloc().
+**
+** When a savepoint is created, the PagerSavepoint.iHdrOffset field is
+** set to 0. If a journal-header is written into the main journal while
+** the savepoint is active, then iHdrOffset is set to the byte offset
+** immediately following the last journal record written into the main
+** journal before the journal-header. This is required during savepoint
+** rollback (see pagerPlaybackSavepoint()).
+*/
+typedef struct PagerSavepoint PagerSavepoint;
+struct PagerSavepoint {
+  i64 iOffset;                 /* Starting offset in main journal */
+  i64 iHdrOffset;              /* See above */
+  Bitvec *pInSavepoint;        /* Set of pages in this savepoint */
+  Pgno nOrig;                  /* Original number of pages in file */
+  Pgno iSubRec;                /* Index of first record in sub-journal */
+  int bTruncateOnRelease;      /* If stmt journal may be truncated on RELEASE */
+#ifndef SQLITE_OMIT_WAL
+  u32 aWalData[WAL_SAVEPOINT_NDATA];        /* WAL savepoint context */
+#endif
+};
+
+/*
+** Bits of the Pager.doNotSpill flag.  See further description below.
+*/
+#define SPILLFLAG_OFF         0x01 /* Never spill cache.  Set via pragma */
+#define SPILLFLAG_ROLLBACK    0x02 /* Current rolling back, so do not spill */
+#define SPILLFLAG_NOSYNC      0x04 /* Spill is ok, but do not sync */
+
+/*
+** An open page cache is an instance of struct Pager. A description of
+** some of the more important member variables follows:
+**
+** eState
+**
+**   The current 'state' of the pager object. See the comment and state
+**   diagram above for a description of the pager state.
+**
+** eLock
+**
+**   For a real on-disk database, the current lock held on the database file -
+**   NO_LOCK, SHARED_LOCK, RESERVED_LOCK or EXCLUSIVE_LOCK.
+**
+**   For a temporary or in-memory database (neither of which require any
+**   locks), this variable is always set to EXCLUSIVE_LOCK. Since such
+**   databases always have Pager.exclusiveMode==1, this tricks the pager
+**   logic into thinking that it already has all the locks it will ever
+**   need (and no reason to release them).
+**
+**   In some (obscure) circumstances, this variable may also be set to
+**   UNKNOWN_LOCK. See the comment above the #define of UNKNOWN_LOCK for
+**   details.
+**
+** changeCountDone
+**
+**   This boolean variable is used to make sure that the change-counter
+**   (the 4-byte header field at byte offset 24 of the database file) is
+**   not updated more often than necessary.
+**
+**   It is set to true when the change-counter field is updated, which
+**   can only happen if an exclusive lock is held on the database file.
+**   It is cleared (set to false) whenever an exclusive lock is
+**   relinquished on the database file. Each time a transaction is committed,
+**   The changeCountDone flag is inspected. If it is true, the work of
+**   updating the change-counter is omitted for the current transaction.
+**
+**   This mechanism means that when running in exclusive mode, a connection
+**   need only update the change-counter once, for the first transaction
+**   committed.
+**
+** setSuper
+**
+**   When PagerCommitPhaseOne() is called to commit a transaction, it may
+**   (or may not) specify a super-journal name to be written into the
+**   journal file before it is synced to disk.
+**
+**   Whether or not a journal file contains a super-journal pointer affects
+**   the way in which the journal file is finalized after the transaction is
+**   committed or rolled back when running in "journal_mode=PERSIST" mode.
+**   If a journal file does not contain a super-journal pointer, it is
+**   finalized by overwriting the first journal header with zeroes. If
+**   it does contain a super-journal pointer the journal file is finalized
+**   by truncating it to zero bytes, just as if the connection were
+**   running in "journal_mode=truncate" mode.
+**
+**   Journal files that contain super-journal pointers cannot be finalized
+**   simply by overwriting the first journal-header with zeroes, as the
+**   super-journal pointer could interfere with hot-journal rollback of any
+**   subsequently interrupted transaction that reuses the journal file.
+**
+**   The flag is cleared as soon as the journal file is finalized (either
+**   by PagerCommitPhaseTwo or PagerRollback). If an IO error prevents the
+**   journal file from being successfully finalized, the setSuper flag
+**   is cleared anyway (and the pager will move to ERROR state).
+**
+** doNotSpill
+**
+**   This variables control the behavior of cache-spills  (calls made by
+**   the pcache module to the pagerStress() routine to write cached data
+**   to the file-system in order to free up memory).
+**
+**   When bits SPILLFLAG_OFF or SPILLFLAG_ROLLBACK of doNotSpill are set,
+**   writing to the database from pagerStress() is disabled altogether.
+**   The SPILLFLAG_ROLLBACK case is done in a very obscure case that
+**   comes up during savepoint rollback that requires the pcache module
+**   to allocate a new page to prevent the journal file from being written
+**   while it is being traversed by code in pager_playback().  The SPILLFLAG_OFF
+**   case is a user preference.
+**
+**   If the SPILLFLAG_NOSYNC bit is set, writing to the database from
+**   pagerStress() is permitted, but syncing the journal file is not.
+**   This flag is set by sqlite3PagerWrite() when the file-system sector-size
+**   is larger than the database page-size in order to prevent a journal sync
+**   from happening in between the journalling of two pages on the same sector.
+**
+** subjInMemory
+**
+**   This is a boolean variable. If true, then any required sub-journal
+**   is opened as an in-memory journal file. If false, then in-memory
+**   sub-journals are only used for in-memory pager files.
+**
+**   This variable is updated by the upper layer each time a new
+**   write-transaction is opened.
+**
+** dbSize, dbOrigSize, dbFileSize
+**
+**   Variable dbSize is set to the number of pages in the database file.
+**   It is valid in PAGER_READER and higher states (all states except for
+**   OPEN and ERROR).
+**
+**   dbSize is set based on the size of the database file, which may be
+**   larger than the size of the database (the value stored at offset
+**   28 of the database header by the btree). If the size of the file
+**   is not an integer multiple of the page-size, the value stored in
+**   dbSize is rounded down (i.e. a 5KB file with 2K page-size has dbSize==2).
+**   Except, any file that is greater than 0 bytes in size is considered
+**   to have at least one page. (i.e. a 1KB file with 2K page-size leads
+**   to dbSize==1).
+**
+**   During a write-transaction, if pages with page-numbers greater than
+**   dbSize are modified in the cache, dbSize is updated accordingly.
+**   Similarly, if the database is truncated using PagerTruncateImage(),
+**   dbSize is updated.
+**
+**   Variables dbOrigSize and dbFileSize are valid in states
+**   PAGER_WRITER_LOCKED and higher. dbOrigSize is a copy of the dbSize
+**   variable at the start of the transaction. It is used during rollback,
+**   and to determine whether or not pages need to be journalled before
+**   being modified.
+**
+**   Throughout a write-transaction, dbFileSize contains the size of
+**   the file on disk in pages. It is set to a copy of dbSize when the
+**   write-transaction is first opened, and updated when VFS calls are made
+**   to write or truncate the database file on disk.
+**
+**   The only reason the dbFileSize variable is required is to suppress
+**   unnecessary calls to xTruncate() after committing a transaction. If,
+**   when a transaction is committed, the dbFileSize variable indicates
+**   that the database file is larger than the database image (Pager.dbSize),
+**   pager_truncate() is called. The pager_truncate() call uses xFilesize()
+**   to measure the database file on disk, and then truncates it if required.
+**   dbFileSize is not used when rolling back a transaction. In this case
+**   pager_truncate() is called unconditionally (which means there may be
+**   a call to xFilesize() that is not strictly required). In either case,
+**   pager_truncate() may cause the file to become smaller or larger.
+**
+** dbHintSize
+**
+**   The dbHintSize variable is used to limit the number of calls made to
+**   the VFS xFileControl(FCNTL_SIZE_HINT) method.
+**
+**   dbHintSize is set to a copy of the dbSize variable when a
+**   write-transaction is opened (at the same time as dbFileSize and
+**   dbOrigSize). If the xFileControl(FCNTL_SIZE_HINT) method is called,
+**   dbHintSize is increased to the number of pages that correspond to the
+**   size-hint passed to the method call. See pager_write_pagelist() for
+**   details.
+**
+** errCode
+**
+**   The Pager.errCode variable is only ever used in PAGER_ERROR state. It
+**   is set to zero in all other states. In PAGER_ERROR state, Pager.errCode
+**   is always set to SQLITE_FULL, SQLITE_IOERR or one of the SQLITE_IOERR_XXX
+**   sub-codes.
+**
+** syncFlags, walSyncFlags
+**
+**   syncFlags is either SQLITE_SYNC_NORMAL (0x02) or SQLITE_SYNC_FULL (0x03).
+**   syncFlags is used for rollback mode.  walSyncFlags is used for WAL mode
+**   and contains the flags used to sync the checkpoint operations in the
+**   lower two bits, and sync flags used for transaction commits in the WAL
+**   file in bits 0x04 and 0x08.  In other words, to get the correct sync flags
+**   for checkpoint operations, use (walSyncFlags&0x03) and to get the correct
+**   sync flags for transaction commit, use ((walSyncFlags>>2)&0x03).  Note
+**   that with synchronous=NORMAL in WAL mode, transaction commit is not synced
+**   meaning that the 0x04 and 0x08 bits are both zero.
+*/
+struct Pager {
+  sqlite3_vfs *pVfs;          /* OS functions to use for IO */
+  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
+  u8 journalMode;             /* One of the PAGER_JOURNALMODE_* values */
+  u8 useJournal;              /* Use a rollback journal on this file */
+  u8 noSync;                  /* Do not sync the journal if true */
+  u8 fullSync;                /* Do extra syncs of the journal for robustness */
+  u8 extraSync;               /* sync directory after journal delete */
+  u8 syncFlags;               /* SYNC_NORMAL or SYNC_FULL otherwise */
+  u8 walSyncFlags;            /* See description above */
+  u8 tempFile;                /* zFilename is a temporary or immutable file */
+  u8 noLock;                  /* Do not lock (except in WAL mode) */
+  u8 readOnly;                /* True for a read-only database */
+  u8 memDb;                   /* True to inhibit all file I/O */
+  u8 memVfs;                  /* VFS-implemented memory database */
+
+  /**************************************************************************
+  ** The following block contains those class members that change during
+  ** routine operation.  Class members not in this block are either fixed
+  ** when the pager is first created or else only change when there is a
+  ** significant mode change (such as changing the page_size, locking_mode,
+  ** or the journal_mode).  From another view, these class members describe
+  ** the "state" of the pager, while other class members describe the
+  ** "configuration" of the pager.
+  */
+  u8 eState;                  /* Pager state (OPEN, READER, WRITER_LOCKED..) */
+  u8 eLock;                   /* Current lock held on database file */
+  u8 changeCountDone;         /* Set after incrementing the change-counter */
+  u8 setSuper;                /* Super-jrnl name is written into jrnl */
+  u8 doNotSpill;              /* Do not spill the cache when non-zero */
+  u8 subjInMemory;            /* True to use in-memory sub-journals */
+  u8 bUseFetch;               /* True to use xFetch() */
+  u8 hasHeldSharedLock;       /* True if a shared lock has ever been held */
+  Pgno dbSize;                /* Number of pages in the database */
+  Pgno dbOrigSize;            /* dbSize before the current transaction */
+  Pgno dbFileSize;            /* Number of pages in the database file */
+  Pgno dbHintSize;            /* Value passed to FCNTL_SIZE_HINT call */
+  int errCode;                /* One of several kinds of errors */
+  int nRec;                   /* Pages journalled since last j-header written */
+  u32 cksumInit;              /* Quasi-random value added to every checksum */
+  u32 nSubRec;                /* Number of records written to sub-journal */
+  Bitvec *pInJournal;         /* One bit for each page in the database file */
+  sqlite3_file *fd;           /* File descriptor for database */
+  sqlite3_file *jfd;          /* File descriptor for main journal */
+  sqlite3_file *sjfd;         /* File descriptor for sub-journal */
+  i64 journalOff;             /* Current write offset in the journal file */
+  i64 journalHdr;             /* Byte offset to previous journal header */
+  sqlite3_backup *pBackup;    /* Pointer to list of ongoing backup processes */
+  PagerSavepoint *aSavepoint; /* Array of active savepoints */
+  int nSavepoint;             /* Number of elements in aSavepoint[] */
+  u32 iDataVersion;           /* Changes whenever database content changes */
+  char dbFileVers[16];        /* Changes whenever database file changes */
+
+  int nMmapOut;               /* Number of mmap pages currently outstanding */
+  sqlite3_int64 szMmap;       /* Desired maximum mmap size */
+  PgHdr *pMmapFreelist;       /* List of free mmap page headers (pDirty) */
+  /*
+  ** End of the routinely-changing class members
+  ***************************************************************************/
+
+  u16 nExtra;                 /* Add this many bytes to each in-memory page */
+  i16 nReserve;               /* Number of unused bytes at end of each page */
+  u32 vfsFlags;               /* Flags for sqlite3_vfs.xOpen() */
+  u32 sectorSize;             /* Assumed sector size during rollback */
+  Pgno mxPgno;                /* Maximum allowed size of the database */
+  Pgno lckPgno;               /* Page number for the locking page */
+  i64 pageSize;               /* Number of bytes in a page */
+  i64 journalSizeLimit;       /* Size limit for persistent journal files */
+  char *zFilename;            /* Name of the database file */
+  char *zJournal;             /* Name of the journal file */
+  int (*xBusyHandler)(void*); /* Function to call when busy */
+  void *pBusyHandlerArg;      /* Context argument for xBusyHandler */
+  u32 aStat[4];               /* Total cache hits, misses, writes, spills */
+#ifdef SQLITE_TEST
+  int nRead;                  /* Database pages read */
+#endif
+  void (*xReiniter)(DbPage*); /* Call this routine when reloading pages */
+  int (*xGet)(Pager*,Pgno,DbPage**,int); /* Routine to fetch a patch */
+  char *pTmpSpace;            /* Pager.pageSize bytes of space for tmp use */
+  PCache *pPCache;            /* Pointer to page cache object */
+#ifndef SQLITE_OMIT_WAL
+  Wal *pWal;                  /* Write-ahead log used by "journal_mode=wal" */
+  char *zWal;                 /* File name for write-ahead log */
+#endif
+};
+
+/*
+** Indexes for use with Pager.aStat[]. The Pager.aStat[] array contains
+** the values accessed by passing SQLITE_DBSTATUS_CACHE_HIT, CACHE_MISS
+** or CACHE_WRITE to sqlite3_db_status().
+*/
+#define PAGER_STAT_HIT   0
+#define PAGER_STAT_MISS  1
+#define PAGER_STAT_WRITE 2
+#define PAGER_STAT_SPILL 3
+
+/*
+** The following global variables hold counters used for
+** testing purposes only.  These variables do not exist in
+** a non-testing build.  These variables are not thread-safe.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_pager_readdb_count = 0;    /* Number of full pages read from DB */
+SQLITE_API int sqlite3_pager_writedb_count = 0;   /* Number of full pages written to DB */
+SQLITE_API int sqlite3_pager_writej_count = 0;    /* Number of pages written to journal */
+# define PAGER_INCR(v)  v++
+#else
+# define PAGER_INCR(v)
+#endif
+
+
+
+/*
+** Journal files begin with the following magic string.  The data
+** was obtained from /dev/random.  It is used only as a sanity check.
+**
+** Since version 2.8.0, the journal format contains additional sanity
+** checking information.  If the power fails while the journal is being
+** written, semi-random garbage data might appear in the journal
+** file after power is restored.  If an attempt is then made
+** to roll the journal back, the database could be corrupted.  The additional
+** sanity checking data is an attempt to discover the garbage in the
+** journal and ignore it.
+**
+** The sanity checking information for the new journal format consists
+** of a 32-bit checksum on each page of data.  The checksum covers both
+** the page number and the pPager->pageSize bytes of data for the page.
+** This cksum is initialized to a 32-bit random value that appears in the
+** journal file right after the header.  The random initializer is important,
+** because garbage data that appears at the end of a journal is likely
+** data that was once in other files that have now been deleted.  If the
+** garbage data came from an obsolete journal file, the checksums might
+** be correct.  But by initializing the checksum to random value which
+** is different for every journal, we minimize that risk.
+*/
+static const unsigned char aJournalMagic[] = {
+  0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7,
+};
+
+/*
+** The size of the of each page record in the journal is given by
+** the following macro.
+*/
+#define JOURNAL_PG_SZ(pPager)  ((pPager->pageSize) + 8)
+
+/*
+** The journal header size for this pager. This is usually the same
+** size as a single disk sector. See also setSectorSize().
+*/
+#define JOURNAL_HDR_SZ(pPager) (pPager->sectorSize)
+
+/*
+** The macro MEMDB is true if we are dealing with an in-memory database.
+** We do this as a macro so that if the SQLITE_OMIT_MEMORYDB macro is set,
+** the value of MEMDB will be a constant and the compiler will optimize
+** out code that would never execute.
+*/
+#ifdef SQLITE_OMIT_MEMORYDB
+# define MEMDB 0
+#else
+# define MEMDB pPager->memDb
+#endif
+
+/*
+** The macro USEFETCH is true if we are allowed to use the xFetch and xUnfetch
+** interfaces to access the database using memory-mapped I/O.
+*/
+#if SQLITE_MAX_MMAP_SIZE>0
+# define USEFETCH(x) ((x)->bUseFetch)
+#else
+# define USEFETCH(x) 0
+#endif
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+/*
+** Return true if page pgno can be read directly from the database file
+** by the b-tree layer. This is the case if:
+**
+**   (1)  the database file is open
+**   (2)  the VFS for the database is able to do unaligned sub-page reads
+**   (3)  there are no dirty pages in the cache, and
+**   (4)  the desired page is not currently in the wal file.
+*/
+SQLITE_PRIVATE int sqlite3PagerDirectReadOk(Pager *pPager, Pgno pgno){
+  assert( pPager!=0 );
+  assert( pPager->fd!=0 );
+  if( pPager->fd->pMethods==0 ) return 0;  /* Case (1) */
+  if( sqlite3PCacheIsDirty(pPager->pPCache) ) return 0; /* Failed (3) */
+#ifndef SQLITE_OMIT_WAL
+  if( pPager->pWal ){
+    u32 iRead = 0;
+    (void)sqlite3WalFindFrame(pPager->pWal, pgno, &iRead);
+    if( iRead ) return 0;  /* Case (4) */
+  }
+#endif
+  assert( pPager->fd->pMethods->xDeviceCharacteristics!=0 );
+  if( (pPager->fd->pMethods->xDeviceCharacteristics(pPager->fd)
+        & SQLITE_IOCAP_SUBPAGE_READ)==0 ){
+    return 0; /* Case (2) */
+  }
+  return 1;
+}
+#endif
+
+#ifndef SQLITE_OMIT_WAL
+# define pagerUseWal(x) ((x)->pWal!=0)
+#else
+# define pagerUseWal(x) 0
+# define pagerRollbackWal(x) 0
+# define pagerWalFrames(v,w,x,y) 0
+# define pagerOpenWalIfPresent(z) SQLITE_OK
+# define pagerBeginReadTransaction(z) SQLITE_OK
+#endif
+
+#ifndef NDEBUG
+/*
+** Usage:
+**
+**   assert( assert_pager_state(pPager) );
+**
+** This function runs many asserts to try to find inconsistencies in
+** the internal state of the Pager object.
+*/
+static int assert_pager_state(Pager *p){
+  Pager *pPager = p;
+
+  /* State must be valid. */
+  assert( p->eState==PAGER_OPEN
+       || p->eState==PAGER_READER
+       || p->eState==PAGER_WRITER_LOCKED
+       || p->eState==PAGER_WRITER_CACHEMOD
+       || p->eState==PAGER_WRITER_DBMOD
+       || p->eState==PAGER_WRITER_FINISHED
+       || p->eState==PAGER_ERROR
+  );
+
+  /* Regardless of the current state, a temp-file connection always behaves
+  ** as if it has an exclusive lock on the database file. It never updates
+  ** the change-counter field, so the changeCountDone flag is always set.
+  */
+  assert( p->tempFile==0 || p->eLock==EXCLUSIVE_LOCK );
+  assert( p->tempFile==0 || pPager->changeCountDone );
+
+  /* If the useJournal flag is clear, the journal-mode must be "OFF".
+  ** And if the journal-mode is "OFF", the journal file must not be open.
+  */
+  assert( p->journalMode==PAGER_JOURNALMODE_OFF || p->useJournal );
+  assert( p->journalMode!=PAGER_JOURNALMODE_OFF || !isOpen(p->jfd) );
+
+  /* Check that MEMDB implies noSync. And an in-memory journal. Since
+  ** this means an in-memory pager performs no IO at all, it cannot encounter
+  ** either SQLITE_IOERR or SQLITE_FULL during rollback or while finalizing
+  ** a journal file. (although the in-memory journal implementation may
+  ** return SQLITE_IOERR_NOMEM while the journal file is being written). It
+  ** is therefore not possible for an in-memory pager to enter the ERROR
+  ** state.
+  */
+  if( MEMDB ){
+    assert( !isOpen(p->fd) );
+    assert( p->noSync );
+    assert( p->journalMode==PAGER_JOURNALMODE_OFF
+         || p->journalMode==PAGER_JOURNALMODE_MEMORY
+    );
+    assert( p->eState!=PAGER_ERROR && p->eState!=PAGER_OPEN );
+    assert( pagerUseWal(p)==0 );
+  }
+
+  /* If changeCountDone is set, a RESERVED lock or greater must be held
+  ** on the file.
+  */
+  assert( pPager->changeCountDone==0 || pPager->eLock>=RESERVED_LOCK );
+  assert( p->eLock!=PENDING_LOCK );
+
+  switch( p->eState ){
+    case PAGER_OPEN:
+      assert( !MEMDB );
+      assert( pPager->errCode==SQLITE_OK );
+      assert( sqlite3PcacheRefCount(pPager->pPCache)==0 || pPager->tempFile );
+      break;
+
+    case PAGER_READER:
+      assert( pPager->errCode==SQLITE_OK );
+      assert( p->eLock!=UNKNOWN_LOCK );
+      assert( p->eLock>=SHARED_LOCK );
+      break;
+
+    case PAGER_WRITER_LOCKED:
+      assert( p->eLock!=UNKNOWN_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      if( !pagerUseWal(pPager) ){
+        assert( p->eLock>=RESERVED_LOCK );
+      }
+      assert( pPager->dbSize==pPager->dbOrigSize );
+      assert( pPager->dbOrigSize==pPager->dbFileSize );
+      assert( pPager->dbOrigSize==pPager->dbHintSize );
+      assert( pPager->setSuper==0 );
+      break;
+
+    case PAGER_WRITER_CACHEMOD:
+      assert( p->eLock!=UNKNOWN_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      if( !pagerUseWal(pPager) ){
+        /* It is possible that if journal_mode=wal here that neither the
+        ** journal file nor the WAL file are open. This happens during
+        ** a rollback transaction that switches from journal_mode=off
+        ** to journal_mode=wal.
+        */
+        assert( p->eLock>=RESERVED_LOCK );
+        assert( isOpen(p->jfd)
+             || p->journalMode==PAGER_JOURNALMODE_OFF
+             || p->journalMode==PAGER_JOURNALMODE_WAL
+        );
+      }
+      assert( pPager->dbOrigSize==pPager->dbFileSize );
+      assert( pPager->dbOrigSize==pPager->dbHintSize );
+      break;
+
+    case PAGER_WRITER_DBMOD:
+      assert( p->eLock==EXCLUSIVE_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      assert( !pagerUseWal(pPager) );
+      assert( p->eLock>=EXCLUSIVE_LOCK );
+      assert( isOpen(p->jfd)
+           || p->journalMode==PAGER_JOURNALMODE_OFF
+           || p->journalMode==PAGER_JOURNALMODE_WAL
+           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
+      );
+      assert( pPager->dbOrigSize<=pPager->dbHintSize );
+      break;
+
+    case PAGER_WRITER_FINISHED:
+      assert( p->eLock==EXCLUSIVE_LOCK );
+      assert( pPager->errCode==SQLITE_OK );
+      assert( !pagerUseWal(pPager) );
+      assert( isOpen(p->jfd)
+           || p->journalMode==PAGER_JOURNALMODE_OFF
+           || p->journalMode==PAGER_JOURNALMODE_WAL
+           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
+      );
+      break;
+
+    case PAGER_ERROR:
+      /* There must be at least one outstanding reference to the pager if
+      ** in ERROR state. Otherwise the pager should have already dropped
+      ** back to OPEN state.
+      */
+      assert( pPager->errCode!=SQLITE_OK );
+      assert( sqlite3PcacheRefCount(pPager->pPCache)>0 || pPager->tempFile );
+      break;
+  }
+
+  return 1;
+}
+#endif /* ifndef NDEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+** Return a pointer to a human readable string in a static buffer
+** containing the state of the Pager object passed as an argument. This
+** is intended to be used within debuggers. For example, as an alternative
+** to "print *pPager" in gdb:
+**
+** (gdb) printf "%s", print_pager_state(pPager)
+**
+** This routine has external linkage in order to suppress compiler warnings
+** about an unused function.  It is enclosed within SQLITE_DEBUG and so does
+** not appear in normal builds.
+*/
+char *print_pager_state(Pager *p){
+  static char zRet[1024];
+
+  sqlite3_snprintf(1024, zRet,
+      "Filename:      %s\n"
+      "State:         %s errCode=%d\n"
+      "Lock:          %s\n"
+      "Locking mode:  locking_mode=%s\n"
+      "Journal mode:  journal_mode=%s\n"
+      "Backing store: tempFile=%d memDb=%d useJournal=%d\n"
+      "Journal:       journalOff=%lld journalHdr=%lld\n"
+      "Size:          dbsize=%d dbOrigSize=%d dbFileSize=%d\n"
+      , p->zFilename
+      , p->eState==PAGER_OPEN            ? "OPEN" :
+        p->eState==PAGER_READER          ? "READER" :
+        p->eState==PAGER_WRITER_LOCKED   ? "WRITER_LOCKED" :
+        p->eState==PAGER_WRITER_CACHEMOD ? "WRITER_CACHEMOD" :
+        p->eState==PAGER_WRITER_DBMOD    ? "WRITER_DBMOD" :
+        p->eState==PAGER_WRITER_FINISHED ? "WRITER_FINISHED" :
+        p->eState==PAGER_ERROR           ? "ERROR" : "?error?"
+      , (int)p->errCode
+      , p->eLock==NO_LOCK         ? "NO_LOCK" :
+        p->eLock==RESERVED_LOCK   ? "RESERVED" :
+        p->eLock==EXCLUSIVE_LOCK  ? "EXCLUSIVE" :
+        p->eLock==SHARED_LOCK     ? "SHARED" :
+        p->eLock==UNKNOWN_LOCK    ? "UNKNOWN" : "?error?"
+      , p->exclusiveMode ? "exclusive" : "normal"
+      , p->journalMode==PAGER_JOURNALMODE_MEMORY   ? "memory" :
+        p->journalMode==PAGER_JOURNALMODE_OFF      ? "off" :
+        p->journalMode==PAGER_JOURNALMODE_DELETE   ? "delete" :
+        p->journalMode==PAGER_JOURNALMODE_PERSIST  ? "persist" :
+        p->journalMode==PAGER_JOURNALMODE_TRUNCATE ? "truncate" :
+        p->journalMode==PAGER_JOURNALMODE_WAL      ? "wal" : "?error?"
+      , (int)p->tempFile, (int)p->memDb, (int)p->useJournal
+      , p->journalOff, p->journalHdr
+      , (int)p->dbSize, (int)p->dbOrigSize, (int)p->dbFileSize
+  );
+
+  return zRet;
+}
+#endif
+
+/* Forward references to the various page getters */
+static int getPageNormal(Pager*,Pgno,DbPage**,int);
+static int getPageError(Pager*,Pgno,DbPage**,int);
+#if SQLITE_MAX_MMAP_SIZE>0
+static int getPageMMap(Pager*,Pgno,DbPage**,int);
+#endif
+
+/*
+** Set the Pager.xGet method for the appropriate routine used to fetch
+** content from the pager.
+*/
+static void setGetterMethod(Pager *pPager){
+  if( pPager->errCode ){
+    pPager->xGet = getPageError;
+#if SQLITE_MAX_MMAP_SIZE>0
+  }else if( USEFETCH(pPager) ){
+    pPager->xGet = getPageMMap;
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+  }else{
+    pPager->xGet = getPageNormal;
+  }
+}
+
+/*
+** Return true if it is necessary to write page *pPg into the sub-journal.
+** A page needs to be written into the sub-journal if there exists one
+** or more open savepoints for which:
+**
+**   * The page-number is less than or equal to PagerSavepoint.nOrig, and
+**   * The bit corresponding to the page-number is not set in
+**     PagerSavepoint.pInSavepoint.
+*/
+static int subjRequiresPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  PagerSavepoint *p;
+  Pgno pgno = pPg->pgno;
+  int i;
+  for(i=0; i<pPager->nSavepoint; i++){
+    p = &pPager->aSavepoint[i];
+    if( p->nOrig>=pgno && 0==sqlite3BitvecTestNotNull(p->pInSavepoint, pgno) ){
+      for(i=i+1; i<pPager->nSavepoint; i++){
+        pPager->aSavepoint[i].bTruncateOnRelease = 0;
+      }
+      return 1;
+    }
+  }
+  return 0;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Return true if the page is already in the journal file.
+*/
+static int pageInJournal(Pager *pPager, PgHdr *pPg){
+  return sqlite3BitvecTest(pPager->pInJournal, pPg->pgno);
+}
+#endif
+
+/*
+** Read a 32-bit integer from the given file descriptor.  Store the integer
+** that is read in *pRes.  Return SQLITE_OK if everything worked, or an
+** error code is something goes wrong.
+**
+** All values are stored on disk as big-endian.
+*/
+static int read32bits(sqlite3_file *fd, i64 offset, u32 *pRes){
+  unsigned char ac[4];
+  int rc = sqlite3OsRead(fd, ac, sizeof(ac), offset);
+  if( rc==SQLITE_OK ){
+    *pRes = sqlite3Get4byte(ac);
+  }
+  return rc;
+}
+
+/*
+** Write a 32-bit integer into a string buffer in big-endian byte order.
+*/
+#define put32bits(A,B)  sqlite3Put4byte((u8*)A,B)
+
+
+/*
+** Write a 32-bit integer into the given file descriptor.  Return SQLITE_OK
+** on success or an error code is something goes wrong.
+*/
+static int write32bits(sqlite3_file *fd, i64 offset, u32 val){
+  char ac[4];
+  put32bits(ac, val);
+  return sqlite3OsWrite(fd, ac, 4, offset);
+}
+
+/*
+** Unlock the database file to level eLock, which must be either NO_LOCK
+** or SHARED_LOCK. Regardless of whether or not the call to xUnlock()
+** succeeds, set the Pager.eLock variable to match the (attempted) new lock.
+**
+** Except, if Pager.eLock is set to UNKNOWN_LOCK when this function is
+** called, do not modify it. See the comment above the #define of
+** UNKNOWN_LOCK for an explanation of this.
+*/
+static int pagerUnlockDb(Pager *pPager, int eLock){
+  int rc = SQLITE_OK;
+
+  assert( !pPager->exclusiveMode || pPager->eLock==eLock );
+  assert( eLock==NO_LOCK || eLock==SHARED_LOCK );
+  assert( eLock!=NO_LOCK || pagerUseWal(pPager)==0 );
+  if( isOpen(pPager->fd) ){
+    assert( pPager->eLock>=eLock );
+    rc = pPager->noLock ? SQLITE_OK : sqlite3OsUnlock(pPager->fd, eLock);
+    if( pPager->eLock!=UNKNOWN_LOCK ){
+      pPager->eLock = (u8)eLock;
+    }
+    IOTRACE(("UNLOCK %p %d\n", pPager, eLock))
+  }
+  pPager->changeCountDone = pPager->tempFile; /* ticket fb3b3024ea238d5c */
+  return rc;
+}
+
+/*
+** Lock the database file to level eLock, which must be either SHARED_LOCK,
+** RESERVED_LOCK or EXCLUSIVE_LOCK. If the caller is successful, set the
+** Pager.eLock variable to the new locking state.
+**
+** Except, if Pager.eLock is set to UNKNOWN_LOCK when this function is
+** called, do not modify it unless the new locking state is EXCLUSIVE_LOCK.
+** See the comment above the #define of UNKNOWN_LOCK for an explanation
+** of this.
+*/
+static int pagerLockDb(Pager *pPager, int eLock){
+  int rc = SQLITE_OK;
+
+  assert( eLock==SHARED_LOCK || eLock==RESERVED_LOCK || eLock==EXCLUSIVE_LOCK );
+  if( pPager->eLock<eLock || pPager->eLock==UNKNOWN_LOCK ){
+    rc = pPager->noLock ? SQLITE_OK : sqlite3OsLock(pPager->fd, eLock);
+    if( rc==SQLITE_OK && (pPager->eLock!=UNKNOWN_LOCK||eLock==EXCLUSIVE_LOCK) ){
+      pPager->eLock = (u8)eLock;
+      IOTRACE(("LOCK %p %d\n", pPager, eLock))
+    }
+  }
+  return rc;
+}
+
+/*
+** This function determines whether or not the atomic-write or
+** atomic-batch-write optimizations can be used with this pager. The
+** atomic-write optimization can be used if:
+**
+**  (a) the value returned by OsDeviceCharacteristics() indicates that
+**      a database page may be written atomically, and
+**  (b) the value returned by OsSectorSize() is less than or equal
+**      to the page size.
+**
+** If it can be used, then the value returned is the size of the journal
+** file when it contains rollback data for exactly one page.
+**
+** The atomic-batch-write optimization can be used if OsDeviceCharacteristics()
+** returns a value with the SQLITE_IOCAP_BATCH_ATOMIC bit set. -1 is
+** returned in this case.
+**
+** If neither optimization can be used, 0 is returned.
+*/
+static int jrnlBufferSize(Pager *pPager){
+  assert( !MEMDB );
+
+#if defined(SQLITE_ENABLE_ATOMIC_WRITE) \
+ || defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+  int dc;                           /* Device characteristics */
+
+  assert( isOpen(pPager->fd) );
+  dc = sqlite3OsDeviceCharacteristics(pPager->fd);
+#else
+  UNUSED_PARAMETER(pPager);
+#endif
+
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+  if( pPager->dbSize>0 && (dc&SQLITE_IOCAP_BATCH_ATOMIC) ){
+    return -1;
+  }
+#endif
+
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+  {
+    int nSector = pPager->sectorSize;
+    int szPage = pPager->pageSize;
+
+    assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
+    assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
+    if( 0==(dc&(SQLITE_IOCAP_ATOMIC|(szPage>>8)) || nSector>szPage) ){
+      return 0;
+    }
+  }
+
+  return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
+#endif
+
+  return 0;
+}
+
+/*
+** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
+** on the cache using a hash function.  This is used for testing
+** and debugging only.
+*/
+#ifdef SQLITE_CHECK_PAGES
+/*
+** Return a 32-bit hash of the page data for pPage.
+*/
+static u32 pager_datahash(int nByte, unsigned char *pData){
+  u32 hash = 0;
+  int i;
+  for(i=0; i<nByte; i++){
+    hash = (hash*1039) + pData[i];
+  }
+  return hash;
+}
+static u32 pager_pagehash(PgHdr *pPage){
+  return pager_datahash(pPage->pPager->pageSize, (unsigned char *)pPage->pData);
+}
+static void pager_set_pagehash(PgHdr *pPage){
+  pPage->pageHash = pager_pagehash(pPage);
+}
+
+/*
+** The CHECK_PAGE macro takes a PgHdr* as an argument. If SQLITE_CHECK_PAGES
+** is defined, and NDEBUG is not defined, an assert() statement checks
+** that the page is either dirty or still matches the calculated page-hash.
+*/
+#define CHECK_PAGE(x) checkPage(x)
+static void checkPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( (pPg->flags&PGHDR_DIRTY) || pPg->pageHash==pager_pagehash(pPg) );
+}
+
+#else
+#define pager_datahash(X,Y)  0
+#define pager_pagehash(X)  0
+#define pager_set_pagehash(X)
+#define CHECK_PAGE(x)
+#endif  /* SQLITE_CHECK_PAGES */
+
+/*
+** When this is called the journal file for pager pPager must be open.
+** This function attempts to read a super-journal file name from the
+** end of the file and, if successful, copies it into memory supplied
+** by the caller. See comments above writeSuperJournal() for the format
+** used to store a super-journal file name at the end of a journal file.
+**
+** zSuper must point to a buffer of at least nSuper bytes allocated by
+** the caller. This should be sqlite3_vfs.mxPathname+1 (to ensure there is
+** enough space to write the super-journal name). If the super-journal
+** name in the journal is longer than nSuper bytes (including a
+** nul-terminator), then this is handled as if no super-journal name
+** were present in the journal.
+**
+** If a super-journal file name is present at the end of the journal
+** file, then it is copied into the buffer pointed to by zSuper. A
+** nul-terminator byte is appended to the buffer following the
+** super-journal file name.
+**
+** If it is determined that no super-journal file name is present
+** zSuper[0] is set to 0 and SQLITE_OK returned.
+**
+** If an error occurs while reading from the journal file, an SQLite
+** error code is returned.
+*/
+static int readSuperJournal(sqlite3_file *pJrnl, char *zSuper, u32 nSuper){
+  int rc;                    /* Return code */
+  u32 len;                   /* Length in bytes of super-journal name */
+  i64 szJ;                   /* Total size in bytes of journal file pJrnl */
+  u32 cksum;                 /* MJ checksum value read from journal */
+  u32 u;                     /* Unsigned loop counter */
+  unsigned char aMagic[8];   /* A buffer to hold the magic header */
+  zSuper[0] = '\0';
+
+  if( SQLITE_OK!=(rc = sqlite3OsFileSize(pJrnl, &szJ))
+   || szJ<16
+   || SQLITE_OK!=(rc = read32bits(pJrnl, szJ-16, &len))
+   || len>=nSuper
+   || len>szJ-16
+   || len==0
+   || SQLITE_OK!=(rc = read32bits(pJrnl, szJ-12, &cksum))
+   || SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, aMagic, 8, szJ-8))
+   || memcmp(aMagic, aJournalMagic, 8)
+   || SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, zSuper, len, szJ-16-len))
+  ){
+    return rc;
+  }
+
+  /* See if the checksum matches the super-journal name */
+  for(u=0; u<len; u++){
+    cksum -= zSuper[u];
+  }
+  if( cksum ){
+    /* If the checksum doesn't add up, then one or more of the disk sectors
+    ** containing the super-journal filename is corrupted. This means
+    ** definitely roll back, so just return SQLITE_OK and report a (nul)
+    ** super-journal filename.
+    */
+    len = 0;
+  }
+  zSuper[len] = '\0';
+  zSuper[len+1] = '\0';
+
+  return SQLITE_OK;
+}
+
+/*
+** Return the offset of the sector boundary at or immediately
+** following the value in pPager->journalOff, assuming a sector
+** size of pPager->sectorSize bytes.
+**
+** i.e for a sector size of 512:
+**
+**   Pager.journalOff          Return value
+**   ---------------------------------------
+**   0                         0
+**   512                       512
+**   100                       512
+**   2000                      2048
+**
+*/
+static i64 journalHdrOffset(Pager *pPager){
+  i64 offset = 0;
+  i64 c = pPager->journalOff;
+  if( c ){
+    offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager);
+  }
+  assert( offset%JOURNAL_HDR_SZ(pPager)==0 );
+  assert( offset>=c );
+  assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
+  return offset;
+}
+
+/*
+** The journal file must be open when this function is called.
+**
+** This function is a no-op if the journal file has not been written to
+** within the current transaction (i.e. if Pager.journalOff==0).
+**
+** If doTruncate is non-zero or the Pager.journalSizeLimit variable is
+** set to 0, then truncate the journal file to zero bytes in size. Otherwise,
+** zero the 28-byte header at the start of the journal file. In either case,
+** if the pager is not in no-sync mode, sync the journal file immediately
+** after writing or truncating it.
+**
+** If Pager.journalSizeLimit is set to a positive, non-zero value, and
+** following the truncation or zeroing described above the size of the
+** journal file in bytes is larger than this value, then truncate the
+** journal file to Pager.journalSizeLimit bytes. The journal file does
+** not need to be synced following this operation.
+**
+** If an IO error occurs, abandon processing and return the IO error code.
+** Otherwise, return SQLITE_OK.
+*/
+static int zeroJournalHdr(Pager *pPager, int doTruncate){
+  int rc = SQLITE_OK;                               /* Return code */
+  assert( isOpen(pPager->jfd) );
+  assert( !sqlite3JournalIsInMemory(pPager->jfd) );
+  if( pPager->journalOff ){
+    const i64 iLimit = pPager->journalSizeLimit;    /* Local cache of jsl */
+
+    IOTRACE(("JZEROHDR %p\n", pPager))
+    if( doTruncate || iLimit==0 ){
+      rc = sqlite3OsTruncate(pPager->jfd, 0);
+    }else{
+      static const char zeroHdr[28] = {0};
+      rc = sqlite3OsWrite(pPager->jfd, zeroHdr, sizeof(zeroHdr), 0);
+    }
+    if( rc==SQLITE_OK && !pPager->noSync ){
+      rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_DATAONLY|pPager->syncFlags);
+    }
+
+    /* At this point the transaction is committed but the write lock
+    ** is still held on the file. If there is a size limit configured for
+    ** the persistent journal and the journal file currently consumes more
+    ** space than that limit allows for, truncate it now. There is no need
+    ** to sync the file following this operation.
+    */
+    if( rc==SQLITE_OK && iLimit>0 ){
+      i64 sz;
+      rc = sqlite3OsFileSize(pPager->jfd, &sz);
+      if( rc==SQLITE_OK && sz>iLimit ){
+        rc = sqlite3OsTruncate(pPager->jfd, iLimit);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** The journal file must be open when this routine is called. A journal
+** header (JOURNAL_HDR_SZ bytes) is written into the journal file at the
+** current location.
+**
+** The format for the journal header is as follows:
+** - 8 bytes: Magic identifying journal format.
+** - 4 bytes: Number of records in journal, or -1 no-sync mode is on.
+** - 4 bytes: Random number used for page hash.
+** - 4 bytes: Initial database page count.
+** - 4 bytes: Sector size used by the process that wrote this journal.
+** - 4 bytes: Database page size.
+**
+** Followed by (JOURNAL_HDR_SZ - 28) bytes of unused space.
+*/
+static int writeJournalHdr(Pager *pPager){
+  int rc = SQLITE_OK;                 /* Return code */
+  char *zHeader = pPager->pTmpSpace;  /* Temporary space used to build header */
+  u32 nHeader = (u32)pPager->pageSize;/* Size of buffer pointed to by zHeader */
+  u32 nWrite;                         /* Bytes of header sector written */
+  int ii;                             /* Loop counter */
+
+  assert( isOpen(pPager->jfd) );      /* Journal file must be open. */
+
+  if( nHeader>JOURNAL_HDR_SZ(pPager) ){
+    nHeader = JOURNAL_HDR_SZ(pPager);
+  }
+
+  /* If there are active savepoints and any of them were created
+  ** since the most recent journal header was written, update the
+  ** PagerSavepoint.iHdrOffset fields now.
+  */
+  for(ii=0; ii<pPager->nSavepoint; ii++){
+    if( pPager->aSavepoint[ii].iHdrOffset==0 ){
+      pPager->aSavepoint[ii].iHdrOffset = pPager->journalOff;
+    }
+  }
+
+  pPager->journalHdr = pPager->journalOff = journalHdrOffset(pPager);
+
+  /*
+  ** Write the nRec Field - the number of page records that follow this
+  ** journal header. Normally, zero is written to this value at this time.
+  ** After the records are added to the journal (and the journal synced,
+  ** if in full-sync mode), the zero is overwritten with the true number
+  ** of records (see syncJournal()).
+  **
+  ** A faster alternative is to write 0xFFFFFFFF to the nRec field. When
+  ** reading the journal this value tells SQLite to assume that the
+  ** rest of the journal file contains valid page records. This assumption
+  ** is dangerous, as if a failure occurred whilst writing to the journal
+  ** file it may contain some garbage data. There are two scenarios
+  ** where this risk can be ignored:
+  **
+  **   * When the pager is in no-sync mode. Corruption can follow a
+  **     power failure in this case anyway.
+  **
+  **   * When the SQLITE_IOCAP_SAFE_APPEND flag is set. This guarantees
+  **     that garbage data is never appended to the journal file.
+  */
+  assert( isOpen(pPager->fd) || pPager->noSync );
+  if( pPager->noSync || (pPager->journalMode==PAGER_JOURNALMODE_MEMORY)
+   || (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND)
+  ){
+    memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
+    put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
+  }else{
+    memset(zHeader, 0, sizeof(aJournalMagic)+4);
+  }
+
+
+
+  /* The random check-hash initializer */
+  if( pPager->journalMode!=PAGER_JOURNALMODE_MEMORY ){
+    sqlite3_randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
+  }
+#ifdef SQLITE_DEBUG
+  else{
+    /* The Pager.cksumInit variable is usually randomized above to protect
+    ** against there being existing records in the journal file. This is
+    ** dangerous, as following a crash they may be mistaken for records
+    ** written by the current transaction and rolled back into the database
+    ** file, causing corruption. The following assert statements verify
+    ** that this is not required in "journal_mode=memory" mode, as in that
+    ** case the journal file is always 0 bytes in size at this point.
+    ** It is advantageous to avoid the sqlite3_randomness() call if possible
+    ** as it takes the global PRNG mutex.  */
+    i64 sz = 0;
+    sqlite3OsFileSize(pPager->jfd, &sz);
+    assert( sz==0 );
+    assert( pPager->journalOff==journalHdrOffset(pPager) );
+    assert( sqlite3JournalIsInMemory(pPager->jfd) );
+  }
+#endif
+  put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
+
+  /* The initial database size */
+  put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbOrigSize);
+  /* The assumed sector size for this process */
+  put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);
+
+  /* The page size */
+  put32bits(&zHeader[sizeof(aJournalMagic)+16], pPager->pageSize);
+
+  /* Initializing the tail of the buffer is not necessary.  Everything
+  ** works find if the following memset() is omitted.  But initializing
+  ** the memory prevents valgrind from complaining, so we are willing to
+  ** take the performance hit.
+  */
+  memset(&zHeader[sizeof(aJournalMagic)+20], 0,
+         nHeader-(sizeof(aJournalMagic)+20));
+
+  /* In theory, it is only necessary to write the 28 bytes that the
+  ** journal header consumes to the journal file here. Then increment the
+  ** Pager.journalOff variable by JOURNAL_HDR_SZ so that the next
+  ** record is written to the following sector (leaving a gap in the file
+  ** that will be implicitly filled in by the OS).
+  **
+  ** However it has been discovered that on some systems this pattern can
+  ** be significantly slower than contiguously writing data to the file,
+  ** even if that means explicitly writing data to the block of
+  ** (JOURNAL_HDR_SZ - 28) bytes that will not be used. So that is what
+  ** is done.
+  **
+  ** The loop is required here in case the sector-size is larger than the
+  ** database page size. Since the zHeader buffer is only Pager.pageSize
+  ** bytes in size, more than one call to sqlite3OsWrite() may be required
+  ** to populate the entire journal header sector.
+  */
+  for(nWrite=0; rc==SQLITE_OK&&nWrite<JOURNAL_HDR_SZ(pPager); nWrite+=nHeader){
+    IOTRACE(("JHDR %p %lld %d\n", pPager, pPager->journalHdr, nHeader))
+    rc = sqlite3OsWrite(pPager->jfd, zHeader, nHeader, pPager->journalOff);
+    assert( pPager->journalHdr <= pPager->journalOff );
+    pPager->journalOff += nHeader;
+  }
+
+  return rc;
+}
+
+/*
+** The journal file must be open when this is called. A journal header file
+** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
+** file. The current location in the journal file is given by
+** pPager->journalOff. See comments above function writeJournalHdr() for
+** a description of the journal header format.
+**
+** If the header is read successfully, *pNRec is set to the number of
+** page records following this header and *pDbSize is set to the size of the
+** database before the transaction began, in pages. Also, pPager->cksumInit
+** is set to the value read from the journal header. SQLITE_OK is returned
+** in this case.
+**
+** If the journal header file appears to be corrupted, SQLITE_DONE is
+** returned and *pNRec and *PDbSize are undefined.  If JOURNAL_HDR_SZ bytes
+** cannot be read from the journal file an error code is returned.
+*/
+static int readJournalHdr(
+  Pager *pPager,               /* Pager object */
+  int isHot,
+  i64 journalSize,             /* Size of the open journal file in bytes */
+  u32 *pNRec,                  /* OUT: Value read from the nRec field */
+  u32 *pDbSize                 /* OUT: Value of original database size field */
+){
+  int rc;                      /* Return code */
+  unsigned char aMagic[8];     /* A buffer to hold the magic header */
+  i64 iHdrOff;                 /* Offset of journal header being read */
+
+  assert( isOpen(pPager->jfd) );      /* Journal file must be open. */
+
+  /* Advance Pager.journalOff to the start of the next sector. If the
+  ** journal file is too small for there to be a header stored at this
+  ** point, return SQLITE_DONE.
+  */
+  pPager->journalOff = journalHdrOffset(pPager);
+  if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
+    return SQLITE_DONE;
+  }
+  iHdrOff = pPager->journalOff;
+
+  /* Read in the first 8 bytes of the journal header. If they do not match
+  ** the  magic string found at the start of each journal header, return
+  ** SQLITE_DONE. If an IO error occurs, return an error code. Otherwise,
+  ** proceed.
+  */
+  if( isHot || iHdrOff!=pPager->journalHdr ){
+    rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic), iHdrOff);
+    if( rc ){
+      return rc;
+    }
+    if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
+      return SQLITE_DONE;
+    }
+  }
+
+  /* Read the first three 32-bit fields of the journal header: The nRec
+  ** field, the checksum-initializer and the database size at the start
+  ** of the transaction. Return an error code if anything goes wrong.
+  */
+  if( SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+8, pNRec))
+   || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+12, &pPager->cksumInit))
+   || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+16, pDbSize))
+  ){
+    return rc;
+  }
+
+  if( pPager->journalOff==0 ){
+    u32 iPageSize;               /* Page-size field of journal header */
+    u32 iSectorSize;             /* Sector-size field of journal header */
+
+    /* Read the page-size and sector-size journal header fields. */
+    if( SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+20, &iSectorSize))
+     || SQLITE_OK!=(rc = read32bits(pPager->jfd, iHdrOff+24, &iPageSize))
+    ){
+      return rc;
+    }
+
+    /* Versions of SQLite prior to 3.5.8 set the page-size field of the
+    ** journal header to zero. In this case, assume that the Pager.pageSize
+    ** variable is already set to the correct page size.
+    */
+    if( iPageSize==0 ){
+      iPageSize = pPager->pageSize;
+    }
+
+    /* Check that the values read from the page-size and sector-size fields
+    ** are within range. To be 'in range', both values need to be a power
+    ** of two greater than or equal to 512 or 32, and not greater than their
+    ** respective compile time maximum limits.
+    */
+    if( iPageSize<512                  || iSectorSize<32
+     || iPageSize>SQLITE_MAX_PAGE_SIZE || iSectorSize>MAX_SECTOR_SIZE
+     || ((iPageSize-1)&iPageSize)!=0   || ((iSectorSize-1)&iSectorSize)!=0
+    ){
+      /* If the either the page-size or sector-size in the journal-header is
+      ** invalid, then the process that wrote the journal-header must have
+      ** crashed before the header was synced. In this case stop reading
+      ** the journal file here.
+      */
+      return SQLITE_DONE;
+    }
+
+    /* Update the page-size to match the value read from the journal.
+    ** Use a testcase() macro to make sure that malloc failure within
+    ** PagerSetPagesize() is tested.
+    */
+    rc = sqlite3PagerSetPagesize(pPager, &iPageSize, -1);
+    testcase( rc!=SQLITE_OK );
+
+    /* Update the assumed sector-size to match the value used by
+    ** the process that created this journal. If this journal was
+    ** created by a process other than this one, then this routine
+    ** is being called from within pager_playback(). The local value
+    ** of Pager.sectorSize is restored at the end of that routine.
+    */
+    pPager->sectorSize = iSectorSize;
+  }
+
+  pPager->journalOff += JOURNAL_HDR_SZ(pPager);
+  return rc;
+}
+
+
+/*
+** Write the supplied super-journal name into the journal file for pager
+** pPager at the current location. The super-journal name must be the last
+** thing written to a journal file. If the pager is in full-sync mode, the
+** journal file descriptor is advanced to the next sector boundary before
+** anything is written. The format is:
+**
+**   + 4 bytes: PAGER_SJ_PGNO.
+**   + N bytes: super-journal filename in utf-8.
+**   + 4 bytes: N (length of super-journal name in bytes, no nul-terminator).
+**   + 4 bytes: super-journal name checksum.
+**   + 8 bytes: aJournalMagic[].
+**
+** The super-journal page checksum is the sum of the bytes in the super-journal
+** name, where each byte is interpreted as a signed 8-bit integer.
+**
+** If zSuper is a NULL pointer (occurs for a single database transaction),
+** this call is a no-op.
+*/
+static int writeSuperJournal(Pager *pPager, const char *zSuper){
+  int rc;                          /* Return code */
+  int nSuper;                      /* Length of string zSuper */
+  i64 iHdrOff;                     /* Offset of header in journal file */
+  i64 jrnlSize;                    /* Size of journal file on disk */
+  u32 cksum = 0;                   /* Checksum of string zSuper */
+
+  assert( pPager->setSuper==0 );
+  assert( !pagerUseWal(pPager) );
+
+  if( !zSuper
+   || pPager->journalMode==PAGER_JOURNALMODE_MEMORY
+   || !isOpen(pPager->jfd)
+  ){
+    return SQLITE_OK;
+  }
+  pPager->setSuper = 1;
+  assert( pPager->journalHdr <= pPager->journalOff );
+
+  /* Calculate the length in bytes and the checksum of zSuper */
+  for(nSuper=0; zSuper[nSuper]; nSuper++){
+    cksum += zSuper[nSuper];
+  }
+
+  /* If in full-sync mode, advance to the next disk sector before writing
+  ** the super-journal name. This is in case the previous page written to
+  ** the journal has already been synced.
+  */
+  if( pPager->fullSync ){
+    pPager->journalOff = journalHdrOffset(pPager);
+  }
+  iHdrOff = pPager->journalOff;
+
+  /* Write the super-journal data to the end of the journal file. If
+  ** an error occurs, return the error code to the caller.
+  */
+  if( (0 != (rc = write32bits(pPager->jfd, iHdrOff, PAGER_SJ_PGNO(pPager))))
+   || (0 != (rc = sqlite3OsWrite(pPager->jfd, zSuper, nSuper, iHdrOff+4)))
+   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nSuper, nSuper)))
+   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nSuper+4, cksum)))
+   || (0 != (rc = sqlite3OsWrite(pPager->jfd, aJournalMagic, 8,
+                                 iHdrOff+4+nSuper+8)))
+  ){
+    return rc;
+  }
+  pPager->journalOff += (nSuper+20);
+
+  /* If the pager is in persistent-journal mode, then the physical
+  ** journal-file may extend past the end of the super-journal name
+  ** and 8 bytes of magic data just written to the file. This is
+  ** dangerous because the code to rollback a hot-journal file
+  ** will not be able to find the super-journal name to determine
+  ** whether or not the journal is hot.
+  **
+  ** Easiest thing to do in this scenario is to truncate the journal
+  ** file to the required size.
+  */
+  if( SQLITE_OK==(rc = sqlite3OsFileSize(pPager->jfd, &jrnlSize))
+   && jrnlSize>pPager->journalOff
+  ){
+    rc = sqlite3OsTruncate(pPager->jfd, pPager->journalOff);
+  }
+  return rc;
+}
+
+/*
+** Discard the entire contents of the in-memory page-cache.
+*/
+static void pager_reset(Pager *pPager){
+  pPager->iDataVersion++;
+  sqlite3BackupRestart(pPager->pBackup);
+  sqlite3PcacheClear(pPager->pPCache);
+}
+
+/*
+** Return the pPager->iDataVersion value
+*/
+SQLITE_PRIVATE u32 sqlite3PagerDataVersion(Pager *pPager){
+  return pPager->iDataVersion;
+}
+
+/*
+** Free all structures in the Pager.aSavepoint[] array and set both
+** Pager.aSavepoint and Pager.nSavepoint to zero. Close the sub-journal
+** if it is open and the pager is not in exclusive mode.
+*/
+static void releaseAllSavepoints(Pager *pPager){
+  int ii;               /* Iterator for looping through Pager.aSavepoint */
+  for(ii=0; ii<pPager->nSavepoint; ii++){
+    sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
+  }
+  if( !pPager->exclusiveMode || sqlite3JournalIsInMemory(pPager->sjfd) ){
+    sqlite3OsClose(pPager->sjfd);
+  }
+  sqlite3_free(pPager->aSavepoint);
+  pPager->aSavepoint = 0;
+  pPager->nSavepoint = 0;
+  pPager->nSubRec = 0;
+}
+
+/*
+** Set the bit number pgno in the PagerSavepoint.pInSavepoint
+** bitvecs of all open savepoints. Return SQLITE_OK if successful
+** or SQLITE_NOMEM if a malloc failure occurs.
+*/
+static int addToSavepointBitvecs(Pager *pPager, Pgno pgno){
+  int ii;                   /* Loop counter */
+  int rc = SQLITE_OK;       /* Result code */
+
+  for(ii=0; ii<pPager->nSavepoint; ii++){
+    PagerSavepoint *p = &pPager->aSavepoint[ii];
+    if( pgno<=p->nOrig ){
+      rc |= sqlite3BitvecSet(p->pInSavepoint, pgno);
+      testcase( rc==SQLITE_NOMEM );
+      assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is a no-op if the pager is in exclusive mode and not
+** in the ERROR state. Otherwise, it switches the pager to PAGER_OPEN
+** state.
+**
+** If the pager is not in exclusive-access mode, the database file is
+** completely unlocked. If the file is unlocked and the file-system does
+** not exhibit the UNDELETABLE_WHEN_OPEN property, the journal file is
+** closed (if it is open).
+**
+** If the pager is in ERROR state when this function is called, the
+** contents of the pager cache are discarded before switching back to
+** the OPEN state. Regardless of whether the pager is in exclusive-mode
+** or not, any journal file left in the file-system will be treated
+** as a hot-journal and rolled back the next time a read-transaction
+** is opened (by this or by any other connection).
+*/
+static void pager_unlock(Pager *pPager){
+
+  assert( pPager->eState==PAGER_READER
+       || pPager->eState==PAGER_OPEN
+       || pPager->eState==PAGER_ERROR
+  );
+
+  sqlite3BitvecDestroy(pPager->pInJournal);
+  pPager->pInJournal = 0;
+  releaseAllSavepoints(pPager);
+
+  if( pagerUseWal(pPager) ){
+    assert( !isOpen(pPager->jfd) );
+    sqlite3WalEndReadTransaction(pPager->pWal);
+    pPager->eState = PAGER_OPEN;
+  }else if( !pPager->exclusiveMode ){
+    int rc;                       /* Error code returned by pagerUnlockDb() */
+    int iDc = isOpen(pPager->fd)?sqlite3OsDeviceCharacteristics(pPager->fd):0;
+
+    /* If the operating system support deletion of open files, then
+    ** close the journal file when dropping the database lock.  Otherwise
+    ** another connection with journal_mode=delete might delete the file
+    ** out from under us.
+    */
+    assert( (PAGER_JOURNALMODE_MEMORY   & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_OFF      & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_WAL      & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_DELETE   & 5)!=1 );
+    assert( (PAGER_JOURNALMODE_TRUNCATE & 5)==1 );
+    assert( (PAGER_JOURNALMODE_PERSIST  & 5)==1 );
+    if( 0==(iDc & SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN)
+     || 1!=(pPager->journalMode & 5)
+    ){
+      sqlite3OsClose(pPager->jfd);
+    }
+
+    /* If the pager is in the ERROR state and the call to unlock the database
+    ** file fails, set the current lock to UNKNOWN_LOCK. See the comment
+    ** above the #define for UNKNOWN_LOCK for an explanation of why this
+    ** is necessary.
+    */
+    rc = pagerUnlockDb(pPager, NO_LOCK);
+    if( rc!=SQLITE_OK && pPager->eState==PAGER_ERROR ){
+      pPager->eLock = UNKNOWN_LOCK;
+    }
+
+    /* The pager state may be changed from PAGER_ERROR to PAGER_OPEN here
+    ** without clearing the error code. This is intentional - the error
+    ** code is cleared and the cache reset in the block below.
+    */
+    assert( pPager->errCode || pPager->eState!=PAGER_ERROR );
+    pPager->eState = PAGER_OPEN;
+  }
+
+  /* If Pager.errCode is set, the contents of the pager cache cannot be
+  ** trusted. Now that there are no outstanding references to the pager,
+  ** it can safely move back to PAGER_OPEN state. This happens in both
+  ** normal and exclusive-locking mode.
+  */
+  assert( pPager->errCode==SQLITE_OK || !MEMDB );
+  if( pPager->errCode ){
+    if( pPager->tempFile==0 ){
+      pager_reset(pPager);
+      pPager->changeCountDone = 0;
+      pPager->eState = PAGER_OPEN;
+    }else{
+      pPager->eState = (isOpen(pPager->jfd) ? PAGER_OPEN : PAGER_READER);
+    }
+    if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);
+    pPager->errCode = SQLITE_OK;
+    setGetterMethod(pPager);
+  }
+
+  pPager->journalOff = 0;
+  pPager->journalHdr = 0;
+  pPager->setSuper = 0;
+}
+
+/*
+** This function is called whenever an IOERR or FULL error that requires
+** the pager to transition into the ERROR state may have occurred.
+** The first argument is a pointer to the pager structure, the second
+** the error-code about to be returned by a pager API function. The
+** value returned is a copy of the second argument to this function.
+**
+** If the second argument is SQLITE_FULL, SQLITE_IOERR or one of the
+** IOERR sub-codes, the pager enters the ERROR state and the error code
+** is stored in Pager.errCode. While the pager remains in the ERROR state,
+** all major API calls on the Pager will immediately return Pager.errCode.
+**
+** The ERROR state indicates that the contents of the pager-cache
+** cannot be trusted. This state can be cleared by completely discarding
+** the contents of the pager-cache. If a transaction was active when
+** the persistent error occurred, then the rollback journal may need
+** to be replayed to restore the contents of the database file (as if
+** it were a hot-journal).
+*/
+static int pager_error(Pager *pPager, int rc){
+  int rc2 = rc & 0xff;
+  assert( rc==SQLITE_OK || !MEMDB );
+  assert(
+       pPager->errCode==SQLITE_FULL ||
+       pPager->errCode==SQLITE_OK ||
+       (pPager->errCode & 0xff)==SQLITE_IOERR
+  );
+  if( rc2==SQLITE_FULL || rc2==SQLITE_IOERR ){
+    pPager->errCode = rc;
+    pPager->eState = PAGER_ERROR;
+    setGetterMethod(pPager);
+  }
+  return rc;
+}
+
+static int pager_truncate(Pager *pPager, Pgno nPage);
+
+/*
+** The write transaction open on pPager is being committed (bCommit==1)
+** or rolled back (bCommit==0).
+**
+** Return TRUE if and only if all dirty pages should be flushed to disk.
+**
+** Rules:
+**
+**   *  For non-TEMP databases, always sync to disk.  This is necessary
+**      for transactions to be durable.
+**
+**   *  Sync TEMP database only on a COMMIT (not a ROLLBACK) when the backing
+**      file has been created already (via a spill on pagerStress()) and
+**      when the number of dirty pages in memory exceeds 25% of the total
+**      cache size.
+*/
+static int pagerFlushOnCommit(Pager *pPager, int bCommit){
+  if( pPager->tempFile==0 ) return 1;
+  if( !bCommit ) return 0;
+  if( !isOpen(pPager->fd) ) return 0;
+  return (sqlite3PCachePercentDirty(pPager->pPCache)>=25);
+}
+
+/*
+** This routine ends a transaction. A transaction is usually ended by
+** either a COMMIT or a ROLLBACK operation. This routine may be called
+** after rollback of a hot-journal, or if an error occurs while opening
+** the journal file or writing the very first journal-header of a
+** database transaction.
+**
+** This routine is never called in PAGER_ERROR state. If it is called
+** in PAGER_NONE or PAGER_SHARED state and the lock held is less
+** exclusive than a RESERVED lock, it is a no-op.
+**
+** Otherwise, any active savepoints are released.
+**
+** If the journal file is open, then it is "finalized". Once a journal
+** file has been finalized it is not possible to use it to roll back a
+** transaction. Nor will it be considered to be a hot-journal by this
+** or any other database connection. Exactly how a journal is finalized
+** depends on whether or not the pager is running in exclusive mode and
+** the current journal-mode (Pager.journalMode value), as follows:
+**
+**   journalMode==MEMORY
+**     Journal file descriptor is simply closed. This destroys an
+**     in-memory journal.
+**
+**   journalMode==TRUNCATE
+**     Journal file is truncated to zero bytes in size.
+**
+**   journalMode==PERSIST
+**     The first 28 bytes of the journal file are zeroed. This invalidates
+**     the first journal header in the file, and hence the entire journal
+**     file. An invalid journal file cannot be rolled back.
+**
+**   journalMode==DELETE
+**     The journal file is closed and deleted using sqlite3OsDelete().
+**
+**     If the pager is running in exclusive mode, this method of finalizing
+**     the journal file is never used. Instead, if the journalMode is
+**     DELETE and the pager is in exclusive mode, the method described under
+**     journalMode==PERSIST is used instead.
+**
+** After the journal is finalized, the pager moves to PAGER_READER state.
+** If running in non-exclusive rollback mode, the lock on the file is
+** downgraded to a SHARED_LOCK.
+**
+** SQLITE_OK is returned if no error occurs. If an error occurs during
+** any of the IO operations to finalize the journal file or unlock the
+** database then the IO error code is returned to the user. If the
+** operation to finalize the journal file fails, then the code still
+** tries to unlock the database file if not in exclusive mode. If the
+** unlock operation fails as well, then the first error code related
+** to the first error encountered (the journal finalization one) is
+** returned.
+*/
+static int pager_end_transaction(Pager *pPager, int hasSuper, int bCommit){
+  int rc = SQLITE_OK;      /* Error code from journal finalization operation */
+  int rc2 = SQLITE_OK;     /* Error code from db file unlock operation */
+
+  /* Do nothing if the pager does not have an open write transaction
+  ** or at least a RESERVED lock. This function may be called when there
+  ** is no write-transaction active but a RESERVED or greater lock is
+  ** held under two circumstances:
+  **
+  **   1. After a successful hot-journal rollback, it is called with
+  **      eState==PAGER_NONE and eLock==EXCLUSIVE_LOCK.
+  **
+  **   2. If a connection with locking_mode=exclusive holding an EXCLUSIVE
+  **      lock switches back to locking_mode=normal and then executes a
+  **      read-transaction, this function is called with eState==PAGER_READER
+  **      and eLock==EXCLUSIVE_LOCK when the read-transaction is closed.
+  */
+  assert( assert_pager_state(pPager) );
+  assert( pPager->eState!=PAGER_ERROR );
+  if( pPager->eState<PAGER_WRITER_LOCKED && pPager->eLock<RESERVED_LOCK ){
+    return SQLITE_OK;
+  }
+
+  releaseAllSavepoints(pPager);
+  assert( isOpen(pPager->jfd) || pPager->pInJournal==0
+      || (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
+  );
+  if( isOpen(pPager->jfd) ){
+    assert( !pagerUseWal(pPager) );
+
+    /* Finalize the journal file. */
+    if( sqlite3JournalIsInMemory(pPager->jfd) ){
+      /* assert( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ); */
+      sqlite3OsClose(pPager->jfd);
+    }else if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE ){
+      if( pPager->journalOff==0 ){
+        rc = SQLITE_OK;
+      }else{
+        rc = sqlite3OsTruncate(pPager->jfd, 0);
+        if( rc==SQLITE_OK && pPager->fullSync ){
+          /* Make sure the new file size is written into the inode right away.
+          ** Otherwise the journal might resurrect following a power loss and
+          ** cause the last transaction to roll back.  See
+          ** https://bugzilla.mozilla.org/show_bug.cgi?id=1072773
+          */
+          rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags);
+        }
+      }
+      pPager->journalOff = 0;
+    }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
+      || (pPager->exclusiveMode && pPager->journalMode<PAGER_JOURNALMODE_WAL)
+    ){
+      rc = zeroJournalHdr(pPager, hasSuper||pPager->tempFile);
+      pPager->journalOff = 0;
+    }else{
+      /* This branch may be executed with Pager.journalMode==MEMORY if
+      ** a hot-journal was just rolled back. In this case the journal
+      ** file should be closed and deleted. If this connection writes to
+      ** the database file, it will do so using an in-memory journal.
+      */
+      int bDelete = !pPager->tempFile;
+      assert( sqlite3JournalIsInMemory(pPager->jfd)==0 );
+      assert( pPager->journalMode==PAGER_JOURNALMODE_DELETE
+           || pPager->journalMode==PAGER_JOURNALMODE_MEMORY
+           || pPager->journalMode==PAGER_JOURNALMODE_WAL
+      );
+      sqlite3OsClose(pPager->jfd);
+      if( bDelete ){
+        rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, pPager->extraSync);
+      }
+    }
+  }
+
+#ifdef SQLITE_CHECK_PAGES
+  sqlite3PcacheIterateDirty(pPager->pPCache, pager_set_pagehash);
+  if( pPager->dbSize==0 && sqlite3PcacheRefCount(pPager->pPCache)>0 ){
+    PgHdr *p = sqlite3PagerLookup(pPager, 1);
+    if( p ){
+      p->pageHash = 0;
+      sqlite3PagerUnrefNotNull(p);
+    }
+  }
+#endif
+
+  sqlite3BitvecDestroy(pPager->pInJournal);
+  pPager->pInJournal = 0;
+  pPager->nRec = 0;
+  if( rc==SQLITE_OK ){
+    if( MEMDB || pagerFlushOnCommit(pPager, bCommit) ){
+      sqlite3PcacheCleanAll(pPager->pPCache);
+    }else{
+      sqlite3PcacheClearWritable(pPager->pPCache);
+    }
+    sqlite3PcacheTruncate(pPager->pPCache, pPager->dbSize);
+  }
+
+  if( pagerUseWal(pPager) ){
+    /* Drop the WAL write-lock, if any. Also, if the connection was in
+    ** locking_mode=exclusive mode but is no longer, drop the EXCLUSIVE
+    ** lock held on the database file.
+    */
+    rc2 = sqlite3WalEndWriteTransaction(pPager->pWal);
+    assert( rc2==SQLITE_OK );
+  }else if( rc==SQLITE_OK && bCommit && pPager->dbFileSize>pPager->dbSize ){
+    /* This branch is taken when committing a transaction in rollback-journal
+    ** mode if the database file on disk is larger than the database image.
+    ** At this point the journal has been finalized and the transaction
+    ** successfully committed, but the EXCLUSIVE lock is still held on the
+    ** file. So it is safe to truncate the database file to its minimum
+    ** required size.  */
+    assert( pPager->eLock==EXCLUSIVE_LOCK );
+    rc = pager_truncate(pPager, pPager->dbSize);
+  }
+
+  if( rc==SQLITE_OK && bCommit ){
+    rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_COMMIT_PHASETWO, 0);
+    if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+  }
+
+  if( !pPager->exclusiveMode
+   && (!pagerUseWal(pPager) || sqlite3WalExclusiveMode(pPager->pWal, 0))
+  ){
+    rc2 = pagerUnlockDb(pPager, SHARED_LOCK);
+  }
+  pPager->eState = PAGER_READER;
+  pPager->setSuper = 0;
+
+  return (rc==SQLITE_OK?rc2:rc);
+}
+
+/* Forward reference */
+static int pager_playback(Pager *pPager, int isHot);
+
+/*
+** Execute a rollback if a transaction is active and unlock the
+** database file.
+**
+** If the pager has already entered the ERROR state, do not attempt
+** the rollback at this time. Instead, pager_unlock() is called. The
+** call to pager_unlock() will discard all in-memory pages, unlock
+** the database file and move the pager back to OPEN state. If this
+** means that there is a hot-journal left in the file-system, the next
+** connection to obtain a shared lock on the pager (which may be this one)
+** will roll it back.
+**
+** If the pager has not already entered the ERROR state, but an IO or
+** malloc error occurs during a rollback, then this will itself cause
+** the pager to enter the ERROR state. Which will be cleared by the
+** call to pager_unlock(), as described above.
+*/
+static void pagerUnlockAndRollback(Pager *pPager){
+  if( pPager->eState!=PAGER_ERROR && pPager->eState!=PAGER_OPEN ){
+    assert( assert_pager_state(pPager) );
+    if( pPager->eState>=PAGER_WRITER_LOCKED ){
+      sqlite3BeginBenignMalloc();
+      sqlite3PagerRollback(pPager);
+      sqlite3EndBenignMalloc();
+    }else if( !pPager->exclusiveMode ){
+      assert( pPager->eState==PAGER_READER );
+      pager_end_transaction(pPager, 0, 0);
+    }
+  }else if( pPager->eState==PAGER_ERROR
+         && pPager->journalMode==PAGER_JOURNALMODE_MEMORY
+         && isOpen(pPager->jfd)
+  ){
+    /* Special case for a ROLLBACK due to I/O error with an in-memory
+    ** journal:  We have to rollback immediately, before the journal is
+    ** closed, because once it is closed, all content is forgotten. */
+    int errCode = pPager->errCode;
+    u8 eLock = pPager->eLock;
+    pPager->eState = PAGER_OPEN;
+    pPager->errCode = SQLITE_OK;
+    pPager->eLock = EXCLUSIVE_LOCK;
+    pager_playback(pPager, 1);
+    pPager->errCode = errCode;
+    pPager->eLock = eLock;
+  }
+  pager_unlock(pPager);
+}
+
+/*
+** Parameter aData must point to a buffer of pPager->pageSize bytes
+** of data. Compute and return a checksum based on the contents of the
+** page of data and the current value of pPager->cksumInit.
+**
+** This is not a real checksum. It is really just the sum of the
+** random initial value (pPager->cksumInit) and every 200th byte
+** of the page data, starting with byte offset (pPager->pageSize%200).
+** Each byte is interpreted as an 8-bit unsigned integer.
+**
+** Changing the formula used to compute this checksum results in an
+** incompatible journal file format.
+**
+** If journal corruption occurs due to a power failure, the most likely
+** scenario is that one end or the other of the record will be changed.
+** It is much less likely that the two ends of the journal record will be
+** correct and the middle be corrupt.  Thus, this "checksum" scheme,
+** though fast and simple, catches the mostly likely kind of corruption.
+*/
+static u32 pager_cksum(Pager *pPager, const u8 *aData){
+  u32 cksum = pPager->cksumInit;         /* Checksum value to return */
+  int i = pPager->pageSize-200;          /* Loop counter */
+  while( i>0 ){
+    cksum += aData[i];
+    i -= 200;
+  }
+  return cksum;
+}
+
+/*
+** Read a single page from either the journal file (if isMainJrnl==1) or
+** from the sub-journal (if isMainJrnl==0) and playback that page.
+** The page begins at offset *pOffset into the file. The *pOffset
+** value is increased to the start of the next page in the journal.
+**
+** The main rollback journal uses checksums - the statement journal does
+** not.
+**
+** If the page number of the page record read from the (sub-)journal file
+** is greater than the current value of Pager.dbSize, then playback is
+** skipped and SQLITE_OK is returned.
+**
+** If pDone is not NULL, then it is a record of pages that have already
+** been played back.  If the page at *pOffset has already been played back
+** (if the corresponding pDone bit is set) then skip the playback.
+** Make sure the pDone bit corresponding to the *pOffset page is set
+** prior to returning.
+**
+** If the page record is successfully read from the (sub-)journal file
+** and played back, then SQLITE_OK is returned. If an IO error occurs
+** while reading the record from the (sub-)journal file or while writing
+** to the database file, then the IO error code is returned. If data
+** is successfully read from the (sub-)journal file but appears to be
+** corrupted, SQLITE_DONE is returned. Data is considered corrupted in
+** two circumstances:
+**
+**   * If the record page-number is illegal (0 or PAGER_SJ_PGNO), or
+**   * If the record is being rolled back from the main journal file
+**     and the checksum field does not match the record content.
+**
+** Neither of these two scenarios are possible during a savepoint rollback.
+**
+** If this is a savepoint rollback, then memory may have to be dynamically
+** allocated by this function. If this is the case and an allocation fails,
+** SQLITE_NOMEM is returned.
+*/
+static int pager_playback_one_page(
+  Pager *pPager,                /* The pager being played back */
+  i64 *pOffset,                 /* Offset of record to playback */
+  Bitvec *pDone,                /* Bitvec of pages already played back */
+  int isMainJrnl,               /* 1 -> main journal. 0 -> sub-journal. */
+  int isSavepnt                 /* True for a savepoint rollback */
+){
+  int rc;
+  PgHdr *pPg;                   /* An existing page in the cache */
+  Pgno pgno;                    /* The page number of a page in journal */
+  u32 cksum;                    /* Checksum used for sanity checking */
+  char *aData;                  /* Temporary storage for the page */
+  sqlite3_file *jfd;            /* The file descriptor for the journal file */
+  int isSynced;                 /* True if journal page is synced */
+
+  assert( (isMainJrnl&~1)==0 );      /* isMainJrnl is 0 or 1 */
+  assert( (isSavepnt&~1)==0 );       /* isSavepnt is 0 or 1 */
+  assert( isMainJrnl || pDone );     /* pDone always used on sub-journals */
+  assert( isSavepnt || pDone==0 );   /* pDone never used on non-savepoint */
+
+  aData = pPager->pTmpSpace;
+  assert( aData );         /* Temp storage must have already been allocated */
+  assert( pagerUseWal(pPager)==0 || (!isMainJrnl && isSavepnt) );
+
+  /* Either the state is greater than PAGER_WRITER_CACHEMOD (a transaction
+  ** or savepoint rollback done at the request of the caller) or this is
+  ** a hot-journal rollback. If it is a hot-journal rollback, the pager
+  ** is in state OPEN and holds an EXCLUSIVE lock. Hot-journal rollback
+  ** only reads from the main journal, not the sub-journal.
+  */
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD
+       || (pPager->eState==PAGER_OPEN && pPager->eLock==EXCLUSIVE_LOCK)
+  );
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD || isMainJrnl );
+
+  /* Read the page number and page data from the journal or sub-journal
+  ** file. Return an error code to the caller if an IO error occurs.
+  */
+  jfd = isMainJrnl ? pPager->jfd : pPager->sjfd;
+  rc = read32bits(jfd, *pOffset, &pgno);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = sqlite3OsRead(jfd, (u8*)aData, pPager->pageSize, (*pOffset)+4);
+  if( rc!=SQLITE_OK ) return rc;
+  *pOffset += pPager->pageSize + 4 + isMainJrnl*4;
+
+  /* Sanity checking on the page.  This is more important that I originally
+  ** thought.  If a power failure occurs while the journal is being written,
+  ** it could cause invalid data to be written into the journal.  We need to
+  ** detect this invalid data (with high probability) and ignore it.
+  */
+  if( pgno==0 || pgno==PAGER_SJ_PGNO(pPager) ){
+    assert( !isSavepnt );
+    return SQLITE_DONE;
+  }
+  if( pgno>(Pgno)pPager->dbSize || sqlite3BitvecTest(pDone, pgno) ){
+    return SQLITE_OK;
+  }
+  if( isMainJrnl ){
+    rc = read32bits(jfd, (*pOffset)-4, &cksum);
+    if( rc ) return rc;
+    if( !isSavepnt && pager_cksum(pPager, (u8*)aData)!=cksum ){
+      return SQLITE_DONE;
+    }
+  }
+
+  /* If this page has already been played back before during the current
+  ** rollback, then don't bother to play it back again.
+  */
+  if( pDone && (rc = sqlite3BitvecSet(pDone, pgno))!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* When playing back page 1, restore the nReserve setting
+  */
+  if( pgno==1 && pPager->nReserve!=((u8*)aData)[20] ){
+    pPager->nReserve = ((u8*)aData)[20];
+  }
+
+  /* If the pager is in CACHEMOD state, then there must be a copy of this
+  ** page in the pager cache. In this case just update the pager cache,
+  ** not the database file. The page is left marked dirty in this case.
+  **
+  ** An exception to the above rule: If the database is in no-sync mode
+  ** and a page is moved during an incremental vacuum then the page may
+  ** not be in the pager cache. Later: if a malloc() or IO error occurs
+  ** during a Movepage() call, then the page may not be in the cache
+  ** either. So the condition described in the above paragraph is not
+  ** assert()able.
+  **
+  ** If in WRITER_DBMOD, WRITER_FINISHED or OPEN state, then we update the
+  ** pager cache if it exists and the main file. The page is then marked
+  ** not dirty. Since this code is only executed in PAGER_OPEN state for
+  ** a hot-journal rollback, it is guaranteed that the page-cache is empty
+  ** if the pager is in OPEN state.
+  **
+  ** Ticket #1171:  The statement journal might contain page content that is
+  ** different from the page content at the start of the transaction.
+  ** This occurs when a page is changed prior to the start of a statement
+  ** then changed again within the statement.  When rolling back such a
+  ** statement we must not write to the original database unless we know
+  ** for certain that original page contents are synced into the main rollback
+  ** journal.  Otherwise, a power loss might leave modified data in the
+  ** database file without an entry in the rollback journal that can
+  ** restore the database to its original form.  Two conditions must be
+  ** met before writing to the database files. (1) the database must be
+  ** locked.  (2) we know that the original page content is fully synced
+  ** in the main journal either because the page is not in cache or else
+  ** the page is marked as needSync==0.
+  **
+  ** 2008-04-14:  When attempting to vacuum a corrupt database file, it
+  ** is possible to fail a statement on a database that does not yet exist.
+  ** Do not attempt to write if database file has never been opened.
+  */
+  if( pagerUseWal(pPager) ){
+    pPg = 0;
+  }else{
+    pPg = sqlite3PagerLookup(pPager, pgno);
+  }
+  assert( pPg || !MEMDB );
+  assert( pPager->eState!=PAGER_OPEN || pPg==0 || pPager->tempFile );
+  PAGERTRACE(("PLAYBACK %d page %d hash(%08x) %s\n",
+           PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, (u8*)aData),
+           (isMainJrnl?"main-journal":"sub-journal")
+  ));
+  if( isMainJrnl ){
+    isSynced = pPager->noSync || (*pOffset <= pPager->journalHdr);
+  }else{
+    isSynced = (pPg==0 || 0==(pPg->flags & PGHDR_NEED_SYNC));
+  }
+  if( isOpen(pPager->fd)
+   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
+   && isSynced
+  ){
+    i64 ofst = (pgno-1)*(i64)pPager->pageSize;
+    testcase( !isSavepnt && pPg!=0 && (pPg->flags&PGHDR_NEED_SYNC)!=0 );
+    assert( !pagerUseWal(pPager) );
+
+    /* Write the data read from the journal back into the database file.
+    ** This is usually safe even for an encrypted database - as the data
+    ** was encrypted before it was written to the journal file. The exception
+    ** is if the data was just read from an in-memory sub-journal. In that
+    ** case it must be encrypted here before it is copied into the database
+    ** file.  */
+    rc = sqlite3OsWrite(pPager->fd, (u8 *)aData, pPager->pageSize, ofst);
+
+    if( pgno>pPager->dbFileSize ){
+      pPager->dbFileSize = pgno;
+    }
+    if( pPager->pBackup ){
+      sqlite3BackupUpdate(pPager->pBackup, pgno, (u8*)aData);
+    }
+  }else if( !isMainJrnl && pPg==0 ){
+    /* If this is a rollback of a savepoint and data was not written to
+    ** the database and the page is not in-memory, there is a potential
+    ** problem. When the page is next fetched by the b-tree layer, it
+    ** will be read from the database file, which may or may not be
+    ** current.
+    **
+    ** There are a couple of different ways this can happen. All are quite
+    ** obscure. When running in synchronous mode, this can only happen
+    ** if the page is on the free-list at the start of the transaction, then
+    ** populated, then moved using sqlite3PagerMovepage().
+    **
+    ** The solution is to add an in-memory page to the cache containing
+    ** the data just read from the sub-journal. Mark the page as dirty
+    ** and if the pager requires a journal-sync, then mark the page as
+    ** requiring a journal-sync before it is written.
+    */
+    assert( isSavepnt );
+    assert( (pPager->doNotSpill & SPILLFLAG_ROLLBACK)==0 );
+    pPager->doNotSpill |= SPILLFLAG_ROLLBACK;
+    rc = sqlite3PagerGet(pPager, pgno, &pPg, 1);
+    assert( (pPager->doNotSpill & SPILLFLAG_ROLLBACK)!=0 );
+    pPager->doNotSpill &= ~SPILLFLAG_ROLLBACK;
+    if( rc!=SQLITE_OK ) return rc;
+    sqlite3PcacheMakeDirty(pPg);
+  }
+  if( pPg ){
+    /* No page should ever be explicitly rolled back that is in use, except
+    ** for page 1 which is held in use in order to keep the lock on the
+    ** database active. However such a page may be rolled back as a result
+    ** of an internal error resulting in an automatic call to
+    ** sqlite3PagerRollback().
+    */
+    void *pData;
+    pData = pPg->pData;
+    memcpy(pData, (u8*)aData, pPager->pageSize);
+    pPager->xReiniter(pPg);
+    /* It used to be that sqlite3PcacheMakeClean(pPg) was called here.  But
+    ** that call was dangerous and had no detectable benefit since the cache
+    ** is normally cleaned by sqlite3PcacheCleanAll() after rollback and so
+    ** has been removed. */
+    pager_set_pagehash(pPg);
+
+    /* If this was page 1, then restore the value of Pager.dbFileVers.
+    ** Do this before any decoding. */
+    if( pgno==1 ){
+      memcpy(&pPager->dbFileVers, &((u8*)pData)[24],sizeof(pPager->dbFileVers));
+    }
+    sqlite3PcacheRelease(pPg);
+  }
+  return rc;
+}
+
+/*
+** Parameter zSuper is the name of a super-journal file. A single journal
+** file that referred to the super-journal file has just been rolled back.
+** This routine checks if it is possible to delete the super-journal file,
+** and does so if it is.
+**
+** Argument zSuper may point to Pager.pTmpSpace. So that buffer is not
+** available for use within this function.
+**
+** When a super-journal file is created, it is populated with the names
+** of all of its child journals, one after another, formatted as utf-8
+** encoded text. The end of each child journal file is marked with a
+** nul-terminator byte (0x00). i.e. the entire contents of a super-journal
+** file for a transaction involving two databases might be:
+**
+**   "/home/bill/a.db-journal\x00/home/bill/b.db-journal\x00"
+**
+** A super-journal file may only be deleted once all of its child
+** journals have been rolled back.
+**
+** This function reads the contents of the super-journal file into
+** memory and loops through each of the child journal names. For
+** each child journal, it checks if:
+**
+**   * if the child journal exists, and if so
+**   * if the child journal contains a reference to super-journal
+**     file zSuper
+**
+** If a child journal can be found that matches both of the criteria
+** above, this function returns without doing anything. Otherwise, if
+** no such child journal can be found, file zSuper is deleted from
+** the file-system using sqlite3OsDelete().
+**
+** If an IO error within this function, an error code is returned. This
+** function allocates memory by calling sqlite3Malloc(). If an allocation
+** fails, SQLITE_NOMEM is returned. Otherwise, if no IO or malloc errors
+** occur, SQLITE_OK is returned.
+**
+** TODO: This function allocates a single block of memory to load
+** the entire contents of the super-journal file. This could be
+** a couple of kilobytes or so - potentially larger than the page
+** size.
+*/
+static int pager_delsuper(Pager *pPager, const char *zSuper){
+  sqlite3_vfs *pVfs = pPager->pVfs;
+  int rc;                   /* Return code */
+  sqlite3_file *pSuper;     /* Malloc'd super-journal file descriptor */
+  sqlite3_file *pJournal;   /* Malloc'd child-journal file descriptor */
+  char *zSuperJournal = 0;  /* Contents of super-journal file */
+  i64 nSuperJournal;        /* Size of super-journal file */
+  char *zJournal;           /* Pointer to one journal within MJ file */
+  char *zSuperPtr;          /* Space to hold super-journal filename */
+  char *zFree = 0;          /* Free this buffer */
+  int nSuperPtr;            /* Amount of space allocated to zSuperPtr[] */
+
+  /* Allocate space for both the pJournal and pSuper file descriptors.
+  ** If successful, open the super-journal file for reading.
+  */
+  pSuper = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile * 2);
+  if( !pSuper ){
+    rc = SQLITE_NOMEM_BKPT;
+    pJournal = 0;
+  }else{
+    const int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_SUPER_JOURNAL);
+    rc = sqlite3OsOpen(pVfs, zSuper, pSuper, flags, 0);
+    pJournal = (sqlite3_file *)(((u8 *)pSuper) + pVfs->szOsFile);
+  }
+  if( rc!=SQLITE_OK ) goto delsuper_out;
+
+  /* Load the entire super-journal file into space obtained from
+  ** sqlite3_malloc() and pointed to by zSuperJournal.   Also obtain
+  ** sufficient space (in zSuperPtr) to hold the names of super-journal
+  ** files extracted from regular rollback-journals.
+  */
+  rc = sqlite3OsFileSize(pSuper, &nSuperJournal);
+  if( rc!=SQLITE_OK ) goto delsuper_out;
+  nSuperPtr = pVfs->mxPathname+1;
+  zFree = sqlite3Malloc(4 + nSuperJournal + nSuperPtr + 2);
+  if( !zFree ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto delsuper_out;
+  }
+  zFree[0] = zFree[1] = zFree[2] = zFree[3] = 0;
+  zSuperJournal = &zFree[4];
+  zSuperPtr = &zSuperJournal[nSuperJournal+2];
+  rc = sqlite3OsRead(pSuper, zSuperJournal, (int)nSuperJournal, 0);
+  if( rc!=SQLITE_OK ) goto delsuper_out;
+  zSuperJournal[nSuperJournal] = 0;
+  zSuperJournal[nSuperJournal+1] = 0;
+
+  zJournal = zSuperJournal;
+  while( (zJournal-zSuperJournal)<nSuperJournal ){
+    int exists;
+    rc = sqlite3OsAccess(pVfs, zJournal, SQLITE_ACCESS_EXISTS, &exists);
+    if( rc!=SQLITE_OK ){
+      goto delsuper_out;
+    }
+    if( exists ){
+      /* One of the journals pointed to by the super-journal exists.
+      ** Open it and check if it points at the super-journal. If
+      ** so, return without deleting the super-journal file.
+      ** NB:  zJournal is really a MAIN_JOURNAL.  But call it a
+      ** SUPER_JOURNAL here so that the VFS will not send the zJournal
+      ** name into sqlite3_database_file_object().
+      */
+      int c;
+      int flags = (SQLITE_OPEN_READONLY|SQLITE_OPEN_SUPER_JOURNAL);
+      rc = sqlite3OsOpen(pVfs, zJournal, pJournal, flags, 0);
+      if( rc!=SQLITE_OK ){
+        goto delsuper_out;
+      }
+
+      rc = readSuperJournal(pJournal, zSuperPtr, nSuperPtr);
+      sqlite3OsClose(pJournal);
+      if( rc!=SQLITE_OK ){
+        goto delsuper_out;
+      }
+
+      c = zSuperPtr[0]!=0 && strcmp(zSuperPtr, zSuper)==0;
+      if( c ){
+        /* We have a match. Do not delete the super-journal file. */
+        goto delsuper_out;
+      }
+    }
+    zJournal += (sqlite3Strlen30(zJournal)+1);
+  }
+
+  sqlite3OsClose(pSuper);
+  rc = sqlite3OsDelete(pVfs, zSuper, 0);
+
+delsuper_out:
+  sqlite3_free(zFree);
+  if( pSuper ){
+    sqlite3OsClose(pSuper);
+    assert( !isOpen(pJournal) );
+    sqlite3_free(pSuper);
+  }
+  return rc;
+}
+
+
+/*
+** This function is used to change the actual size of the database
+** file in the file-system. This only happens when committing a transaction,
+** or rolling back a transaction (including rolling back a hot-journal).
+**
+** If the main database file is not open, or the pager is not in either
+** DBMOD or OPEN state, this function is a no-op. Otherwise, the size
+** of the file is changed to nPage pages (nPage*pPager->pageSize bytes).
+** If the file on disk is currently larger than nPage pages, then use the VFS
+** xTruncate() method to truncate it.
+**
+** Or, it might be the case that the file on disk is smaller than
+** nPage pages. Some operating system implementations can get confused if
+** you try to truncate a file to some size that is larger than it
+** currently is, so detect this case and write a single zero byte to
+** the end of the new file instead.
+**
+** If successful, return SQLITE_OK. If an IO error occurs while modifying
+** the database file, return the error code to the caller.
+*/
+static int pager_truncate(Pager *pPager, Pgno nPage){
+  int rc = SQLITE_OK;
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( pPager->eState!=PAGER_READER );
+  PAGERTRACE(("Truncate %d npage %u\n", PAGERID(pPager), nPage));
+
+
+  if( isOpen(pPager->fd)
+   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
+  ){
+    i64 currentSize, newSize;
+    int szPage = pPager->pageSize;
+    assert( pPager->eLock==EXCLUSIVE_LOCK );
+    /* TODO: Is it safe to use Pager.dbFileSize here? */
+    rc = sqlite3OsFileSize(pPager->fd, ¤tSize);
+    newSize = szPage*(i64)nPage;
+    if( rc==SQLITE_OK && currentSize!=newSize ){
+      if( currentSize>newSize ){
+        rc = sqlite3OsTruncate(pPager->fd, newSize);
+      }else if( (currentSize+szPage)<=newSize ){
+        char *pTmp = pPager->pTmpSpace;
+        memset(pTmp, 0, szPage);
+        testcase( (newSize-szPage) == currentSize );
+        testcase( (newSize-szPage) >  currentSize );
+        sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &newSize);
+        rc = sqlite3OsWrite(pPager->fd, pTmp, szPage, newSize-szPage);
+      }
+      if( rc==SQLITE_OK ){
+        pPager->dbFileSize = nPage;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Return a sanitized version of the sector-size of OS file pFile. The
+** return value is guaranteed to lie between 32 and MAX_SECTOR_SIZE.
+*/
+SQLITE_PRIVATE int sqlite3SectorSize(sqlite3_file *pFile){
+  int iRet = sqlite3OsSectorSize(pFile);
+  if( iRet<32 ){
+    iRet = 512;
+  }else if( iRet>MAX_SECTOR_SIZE ){
+    assert( MAX_SECTOR_SIZE>=512 );
+    iRet = MAX_SECTOR_SIZE;
+  }
+  return iRet;
+}
+
+/*
+** Set the value of the Pager.sectorSize variable for the given
+** pager based on the value returned by the xSectorSize method
+** of the open database file. The sector size will be used
+** to determine the size and alignment of journal header and
+** super-journal pointers within created journal files.
+**
+** For temporary files the effective sector size is always 512 bytes.
+**
+** Otherwise, for non-temporary files, the effective sector size is
+** the value returned by the xSectorSize() method rounded up to 32 if
+** it is less than 32, or rounded down to MAX_SECTOR_SIZE if it
+** is greater than MAX_SECTOR_SIZE.
+**
+** If the file has the SQLITE_IOCAP_POWERSAFE_OVERWRITE property, then set
+** the effective sector size to its minimum value (512).  The purpose of
+** pPager->sectorSize is to define the "blast radius" of bytes that
+** might change if a crash occurs while writing to a single byte in
+** that range.  But with POWERSAFE_OVERWRITE, the blast radius is zero
+** (that is what POWERSAFE_OVERWRITE means), so we minimize the sector
+** size.  For backwards compatibility of the rollback journal file format,
+** we cannot reduce the effective sector size below 512.
+*/
+static void setSectorSize(Pager *pPager){
+  assert( isOpen(pPager->fd) || pPager->tempFile );
+
+  if( pPager->tempFile
+   || (sqlite3OsDeviceCharacteristics(pPager->fd) &
+              SQLITE_IOCAP_POWERSAFE_OVERWRITE)!=0
+  ){
+    /* Sector size doesn't matter for temporary files. Also, the file
+    ** may not have been opened yet, in which case the OsSectorSize()
+    ** call will segfault. */
+    pPager->sectorSize = 512;
+  }else{
+    pPager->sectorSize = sqlite3SectorSize(pPager->fd);
+  }
+}
+
+/*
+** Playback the journal and thus restore the database file to
+** the state it was in before we started making changes.
+**
+** The journal file format is as follows:
+**
+**  (1)  8 byte prefix.  A copy of aJournalMagic[].
+**  (2)  4 byte big-endian integer which is the number of valid page records
+**       in the journal.  If this value is 0xffffffff, then compute the
+**       number of page records from the journal size.
+**  (3)  4 byte big-endian integer which is the initial value for the
+**       sanity checksum.
+**  (4)  4 byte integer which is the number of pages to truncate the
+**       database to during a rollback.
+**  (5)  4 byte big-endian integer which is the sector size.  The header
+**       is this many bytes in size.
+**  (6)  4 byte big-endian integer which is the page size.
+**  (7)  zero padding out to the next sector size.
+**  (8)  Zero or more pages instances, each as follows:
+**        +  4 byte page number.
+**        +  pPager->pageSize bytes of data.
+**        +  4 byte checksum
+**
+** When we speak of the journal header, we mean the first 7 items above.
+** Each entry in the journal is an instance of the 8th item.
+**
+** Call the value from the second bullet "nRec".  nRec is the number of
+** valid page entries in the journal.  In most cases, you can compute the
+** value of nRec from the size of the journal file.  But if a power
+** failure occurred while the journal was being written, it could be the
+** case that the size of the journal file had already been increased but
+** the extra entries had not yet made it safely to disk.  In such a case,
+** the value of nRec computed from the file size would be too large.  For
+** that reason, we always use the nRec value in the header.
+**
+** If the nRec value is 0xffffffff it means that nRec should be computed
+** from the file size.  This value is used when the user selects the
+** no-sync option for the journal.  A power failure could lead to corruption
+** in this case.  But for things like temporary table (which will be
+** deleted when the power is restored) we don't care.
+**
+** If the file opened as the journal file is not a well-formed
+** journal file then all pages up to the first corrupted page are rolled
+** back (or no pages if the journal header is corrupted). The journal file
+** is then deleted and SQLITE_OK returned, just as if no corruption had
+** been encountered.
+**
+** If an I/O or malloc() error occurs, the journal-file is not deleted
+** and an error code is returned.
+**
+** The isHot parameter indicates that we are trying to rollback a journal
+** that might be a hot journal.  Or, it could be that the journal is
+** preserved because of JOURNALMODE_PERSIST or JOURNALMODE_TRUNCATE.
+** If the journal really is hot, reset the pager cache prior rolling
+** back any content.  If the journal is merely persistent, no reset is
+** needed.
+*/
+static int pager_playback(Pager *pPager, int isHot){
+  sqlite3_vfs *pVfs = pPager->pVfs;
+  i64 szJ;                 /* Size of the journal file in bytes */
+  u32 nRec;                /* Number of Records in the journal */
+  u32 u;                   /* Unsigned loop counter */
+  Pgno mxPg = 0;           /* Size of the original file in pages */
+  int rc;                  /* Result code of a subroutine */
+  int res = 1;             /* Value returned by sqlite3OsAccess() */
+  char *zSuper = 0;        /* Name of super-journal file if any */
+  int needPagerReset;      /* True to reset page prior to first page rollback */
+  int nPlayback = 0;       /* Total number of pages restored from journal */
+  u32 savedPageSize = pPager->pageSize;
+
+  /* Figure out how many records are in the journal.  Abort early if
+  ** the journal is empty.
+  */
+  assert( isOpen(pPager->jfd) );
+  rc = sqlite3OsFileSize(pPager->jfd, &szJ);
+  if( rc!=SQLITE_OK ){
+    goto end_playback;
+  }
+
+  /* Read the super-journal name from the journal, if it is present.
+  ** If a super-journal file name is specified, but the file is not
+  ** present on disk, then the journal is not hot and does not need to be
+  ** played back.
+  **
+  ** TODO: Technically the following is an error because it assumes that
+  ** buffer Pager.pTmpSpace is (mxPathname+1) bytes or larger. i.e. that
+  ** (pPager->pageSize >= pPager->pVfs->mxPathname+1). Using os_unix.c,
+  ** mxPathname is 512, which is the same as the minimum allowable value
+  ** for pageSize.
+  */
+  zSuper = pPager->pTmpSpace;
+  rc = readSuperJournal(pPager->jfd, zSuper, pPager->pVfs->mxPathname+1);
+  if( rc==SQLITE_OK && zSuper[0] ){
+    rc = sqlite3OsAccess(pVfs, zSuper, SQLITE_ACCESS_EXISTS, &res);
+  }
+  zSuper = 0;
+  if( rc!=SQLITE_OK || !res ){
+    goto end_playback;
+  }
+  pPager->journalOff = 0;
+  needPagerReset = isHot;
+
+  /* This loop terminates either when a readJournalHdr() or
+  ** pager_playback_one_page() call returns SQLITE_DONE or an IO error
+  ** occurs.
+  */
+  while( 1 ){
+    /* Read the next journal header from the journal file.  If there are
+    ** not enough bytes left in the journal file for a complete header, or
+    ** it is corrupted, then a process must have failed while writing it.
+    ** This indicates nothing more needs to be rolled back.
+    */
+    rc = readJournalHdr(pPager, isHot, szJ, &nRec, &mxPg);
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_DONE ){
+        rc = SQLITE_OK;
+      }
+      goto end_playback;
+    }
+
+    /* If nRec is 0xffffffff, then this journal was created by a process
+    ** working in no-sync mode. This means that the rest of the journal
+    ** file consists of pages, there are no more journal headers. Compute
+    ** the value of nRec based on this assumption.
+    */
+    if( nRec==0xffffffff ){
+      assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
+      nRec = (int)((szJ - JOURNAL_HDR_SZ(pPager))/JOURNAL_PG_SZ(pPager));
+    }
+
+    /* If nRec is 0 and this rollback is of a transaction created by this
+    ** process and if this is the final header in the journal, then it means
+    ** that this part of the journal was being filled but has not yet been
+    ** synced to disk.  Compute the number of pages based on the remaining
+    ** size of the file.
+    **
+    ** The third term of the test was added to fix ticket #2565.
+    ** When rolling back a hot journal, nRec==0 always means that the next
+    ** chunk of the journal contains zero pages to be rolled back.  But
+    ** when doing a ROLLBACK and the nRec==0 chunk is the last chunk in
+    ** the journal, it means that the journal might contain additional
+    ** pages that need to be rolled back and that the number of pages
+    ** should be computed based on the journal file size.
+    */
+    if( nRec==0 && !isHot &&
+        pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff ){
+      nRec = (int)((szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager));
+    }
+
+    /* If this is the first header read from the journal, truncate the
+    ** database file back to its original size.
+    */
+    if( pPager->journalOff==JOURNAL_HDR_SZ(pPager) ){
+      rc = pager_truncate(pPager, mxPg);
+      if( rc!=SQLITE_OK ){
+        goto end_playback;
+      }
+      pPager->dbSize = mxPg;
+      if( pPager->mxPgno<mxPg ){
+        pPager->mxPgno = mxPg;
+      }
+    }
+
+    /* Copy original pages out of the journal and back into the
+    ** database file and/or page cache.
+    */
+    for(u=0; u<nRec; u++){
+      if( needPagerReset ){
+        pager_reset(pPager);
+        needPagerReset = 0;
+      }
+      rc = pager_playback_one_page(pPager,&pPager->journalOff,0,1,0);
+      if( rc==SQLITE_OK ){
+        nPlayback++;
+      }else{
+        if( rc==SQLITE_DONE ){
+          pPager->journalOff = szJ;
+          break;
+        }else if( rc==SQLITE_IOERR_SHORT_READ ){
+          /* If the journal has been truncated, simply stop reading and
+          ** processing the journal. This might happen if the journal was
+          ** not completely written and synced prior to a crash.  In that
+          ** case, the database should have never been written in the
+          ** first place so it is OK to simply abandon the rollback. */
+          rc = SQLITE_OK;
+          goto end_playback;
+        }else{
+          /* If we are unable to rollback, quit and return the error
+          ** code.  This will cause the pager to enter the error state
+          ** so that no further harm will be done.  Perhaps the next
+          ** process to come along will be able to rollback the database.
+          */
+          goto end_playback;
+        }
+      }
+    }
+  }
+  /*NOTREACHED*/
+  assert( 0 );
+
+end_playback:
+  if( rc==SQLITE_OK ){
+    rc = sqlite3PagerSetPagesize(pPager, &savedPageSize, -1);
+  }
+  /* Following a rollback, the database file should be back in its original
+  ** state prior to the start of the transaction, so invoke the
+  ** SQLITE_FCNTL_DB_UNCHANGED file-control method to disable the
+  ** assertion that the transaction counter was modified.
+  */
+#ifdef SQLITE_DEBUG
+  sqlite3OsFileControlHint(pPager->fd,SQLITE_FCNTL_DB_UNCHANGED,0);
+#endif
+
+  /* If this playback is happening automatically as a result of an IO or
+  ** malloc error that occurred after the change-counter was updated but
+  ** before the transaction was committed, then the change-counter
+  ** modification may just have been reverted. If this happens in exclusive
+  ** mode, then subsequent transactions performed by the connection will not
+  ** update the change-counter at all. This may lead to cache inconsistency
+  ** problems for other processes at some point in the future. So, just
+  ** in case this has happened, clear the changeCountDone flag now.
+  */
+  pPager->changeCountDone = pPager->tempFile;
+
+  if( rc==SQLITE_OK ){
+    /* Leave 4 bytes of space before the super-journal filename in memory.
+    ** This is because it may end up being passed to sqlite3OsOpen(), in
+    ** which case it requires 4 0x00 bytes in memory immediately before
+    ** the filename. */
+    zSuper = &pPager->pTmpSpace[4];
+    rc = readSuperJournal(pPager->jfd, zSuper, pPager->pVfs->mxPathname+1);
+    testcase( rc!=SQLITE_OK );
+  }
+  if( rc==SQLITE_OK
+   && (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
+  ){
+    rc = sqlite3PagerSync(pPager, 0);
+  }
+  if( rc==SQLITE_OK ){
+    rc = pager_end_transaction(pPager, zSuper[0]!='\0', 0);
+    testcase( rc!=SQLITE_OK );
+  }
+  if( rc==SQLITE_OK && zSuper[0] && res ){
+    /* If there was a super-journal and this routine will return success,
+    ** see if it is possible to delete the super-journal.
+    */
+    assert( zSuper==&pPager->pTmpSpace[4] );
+    memset(pPager->pTmpSpace, 0, 4);
+    rc = pager_delsuper(pPager, zSuper);
+    testcase( rc!=SQLITE_OK );
+  }
+  if( isHot && nPlayback ){
+    sqlite3_log(SQLITE_NOTICE_RECOVER_ROLLBACK, "recovered %d pages from %s",
+                nPlayback, pPager->zJournal);
+  }
+
+  /* The Pager.sectorSize variable may have been updated while rolling
+  ** back a journal created by a process with a different sector size
+  ** value. Reset it to the correct value for this process.
+  */
+  setSectorSize(pPager);
+  return rc;
+}
+
+
+/*
+** Read the content for page pPg out of the database file (or out of
+** the WAL if that is where the most recent copy if found) into
+** pPg->pData. A shared lock or greater must be held on the database
+** file before this function is called.
+**
+** If page 1 is read, then the value of Pager.dbFileVers[] is set to
+** the value read from the database file.
+**
+** If an IO error occurs, then the IO error is returned to the caller.
+** Otherwise, SQLITE_OK is returned.
+*/
+static int readDbPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager; /* Pager object associated with page pPg */
+  int rc = SQLITE_OK;          /* Return code */
+
+#ifndef SQLITE_OMIT_WAL
+  u32 iFrame = 0;              /* Frame of WAL containing pgno */
+
+  assert( pPager->eState>=PAGER_READER && !MEMDB );
+  assert( isOpen(pPager->fd) );
+
+  if( pagerUseWal(pPager) ){
+    rc = sqlite3WalFindFrame(pPager->pWal, pPg->pgno, &iFrame);
+    if( rc ) return rc;
+  }
+  if( iFrame ){
+    rc = sqlite3WalReadFrame(pPager->pWal, iFrame,pPager->pageSize,pPg->pData);
+  }else
+#endif
+  {
+    i64 iOffset = (pPg->pgno-1)*(i64)pPager->pageSize;
+    rc = sqlite3OsRead(pPager->fd, pPg->pData, pPager->pageSize, iOffset);
+    if( rc==SQLITE_IOERR_SHORT_READ ){
+      rc = SQLITE_OK;
+    }
+  }
+
+  if( pPg->pgno==1 ){
+    if( rc ){
+      /* If the read is unsuccessful, set the dbFileVers[] to something
+      ** that will never be a valid file version.  dbFileVers[] is a copy
+      ** of bytes 24..39 of the database.  Bytes 28..31 should always be
+      ** zero or the size of the database in page. Bytes 32..35 and 35..39
+      ** should be page numbers which are never 0xffffffff.  So filling
+      ** pPager->dbFileVers[] with all 0xff bytes should suffice.
+      **
+      ** For an encrypted database, the situation is more complex:  bytes
+      ** 24..39 of the database are white noise.  But the probability of
+      ** white noise equaling 16 bytes of 0xff is vanishingly small so
+      ** we should still be ok.
+      */
+      memset(pPager->dbFileVers, 0xff, sizeof(pPager->dbFileVers));
+    }else{
+      u8 *dbFileVers = &((u8*)pPg->pData)[24];
+      memcpy(&pPager->dbFileVers, dbFileVers, sizeof(pPager->dbFileVers));
+    }
+  }
+  PAGER_INCR(sqlite3_pager_readdb_count);
+  PAGER_INCR(pPager->nRead);
+  IOTRACE(("PGIN %p %d\n", pPager, pPg->pgno));
+  PAGERTRACE(("FETCH %d page %d hash(%08x)\n",
+               PAGERID(pPager), pPg->pgno, pager_pagehash(pPg)));
+
+  return rc;
+}
+
+/*
+** Update the value of the change-counter at offsets 24 and 92 in
+** the header and the sqlite version number at offset 96.
+**
+** This is an unconditional update.  See also the pager_incr_changecounter()
+** routine which only updates the change-counter if the update is actually
+** needed, as determined by the pPager->changeCountDone state variable.
+*/
+static void pager_write_changecounter(PgHdr *pPg){
+  u32 change_counter;
+  if( NEVER(pPg==0) ) return;
+
+  /* Increment the value just read and write it back to byte 24. */
+  change_counter = sqlite3Get4byte((u8*)pPg->pPager->dbFileVers)+1;
+  put32bits(((char*)pPg->pData)+24, change_counter);
+
+  /* Also store the SQLite version number in bytes 96..99 and in
+  ** bytes 92..95 store the change counter for which the version number
+  ** is valid. */
+  put32bits(((char*)pPg->pData)+92, change_counter);
+  put32bits(((char*)pPg->pData)+96, SQLITE_VERSION_NUMBER);
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** This function is invoked once for each page that has already been
+** written into the log file when a WAL transaction is rolled back.
+** Parameter iPg is the page number of said page. The pCtx argument
+** is actually a pointer to the Pager structure.
+**
+** If page iPg is present in the cache, and has no outstanding references,
+** it is discarded. Otherwise, if there are one or more outstanding
+** references, the page content is reloaded from the database. If the
+** attempt to reload content from the database is required and fails,
+** return an SQLite error code. Otherwise, SQLITE_OK.
+*/
+static int pagerUndoCallback(void *pCtx, Pgno iPg){
+  int rc = SQLITE_OK;
+  Pager *pPager = (Pager *)pCtx;
+  PgHdr *pPg;
+
+  assert( pagerUseWal(pPager) );
+  pPg = sqlite3PagerLookup(pPager, iPg);
+  if( pPg ){
+    if( sqlite3PcachePageRefcount(pPg)==1 ){
+      sqlite3PcacheDrop(pPg);
+    }else{
+      rc = readDbPage(pPg);
+      if( rc==SQLITE_OK ){
+        pPager->xReiniter(pPg);
+      }
+      sqlite3PagerUnrefNotNull(pPg);
+    }
+  }
+
+  /* Normally, if a transaction is rolled back, any backup processes are
+  ** updated as data is copied out of the rollback journal and into the
+  ** database. This is not generally possible with a WAL database, as
+  ** rollback involves simply truncating the log file. Therefore, if one
+  ** or more frames have already been written to the log (and therefore
+  ** also copied into the backup databases) as part of this transaction,
+  ** the backups must be restarted.
+  */
+  sqlite3BackupRestart(pPager->pBackup);
+
+  return rc;
+}
+
+/*
+** This function is called to rollback a transaction on a WAL database.
+*/
+static int pagerRollbackWal(Pager *pPager){
+  int rc;                         /* Return Code */
+  PgHdr *pList;                   /* List of dirty pages to revert */
+
+  /* For all pages in the cache that are currently dirty or have already
+  ** been written (but not committed) to the log file, do one of the
+  ** following:
+  **
+  **   + Discard the cached page (if refcount==0), or
+  **   + Reload page content from the database (if refcount>0).
+  */
+  pPager->dbSize = pPager->dbOrigSize;
+  rc = sqlite3WalUndo(pPager->pWal, pagerUndoCallback, (void *)pPager);
+  pList = sqlite3PcacheDirtyList(pPager->pPCache);
+  while( pList && rc==SQLITE_OK ){
+    PgHdr *pNext = pList->pDirty;
+    rc = pagerUndoCallback((void *)pPager, pList->pgno);
+    pList = pNext;
+  }
+
+  return rc;
+}
+
+/*
+** This function is a wrapper around sqlite3WalFrames(). As well as logging
+** the contents of the list of pages headed by pList (connected by pDirty),
+** this function notifies any active backup processes that the pages have
+** changed.
+**
+** The list of pages passed into this routine is always sorted by page number.
+** Hence, if page 1 appears anywhere on the list, it will be the first page.
+*/
+static int pagerWalFrames(
+  Pager *pPager,                  /* Pager object */
+  PgHdr *pList,                   /* List of frames to log */
+  Pgno nTruncate,                 /* Database size after this commit */
+  int isCommit                    /* True if this is a commit */
+){
+  int rc;                         /* Return code */
+  int nList;                      /* Number of pages in pList */
+  PgHdr *p;                       /* For looping over pages */
+
+  assert( pPager->pWal );
+  assert( pList );
+#ifdef SQLITE_DEBUG
+  /* Verify that the page list is in ascending order */
+  for(p=pList; p && p->pDirty; p=p->pDirty){
+    assert( p->pgno < p->pDirty->pgno );
+  }
+#endif
+
+  assert( pList->pDirty==0 || isCommit );
+  if( isCommit ){
+    /* If a WAL transaction is being committed, there is no point in writing
+    ** any pages with page numbers greater than nTruncate into the WAL file.
+    ** They will never be read by any client. So remove them from the pDirty
+    ** list here. */
+    PgHdr **ppNext = &pList;
+    nList = 0;
+    for(p=pList; (*ppNext = p)!=0; p=p->pDirty){
+      if( p->pgno<=nTruncate ){
+        ppNext = &p->pDirty;
+        nList++;
+      }
+    }
+    assert( pList );
+  }else{
+    nList = 1;
+  }
+  pPager->aStat[PAGER_STAT_WRITE] += nList;
+
+  if( pList->pgno==1 ) pager_write_changecounter(pList);
+  rc = sqlite3WalFrames(pPager->pWal,
+      pPager->pageSize, pList, nTruncate, isCommit, pPager->walSyncFlags
+  );
+  if( rc==SQLITE_OK && pPager->pBackup ){
+    for(p=pList; p; p=p->pDirty){
+      sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
+    }
+  }
+
+#ifdef SQLITE_CHECK_PAGES
+  pList = sqlite3PcacheDirtyList(pPager->pPCache);
+  for(p=pList; p; p=p->pDirty){
+    pager_set_pagehash(p);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** Begin a read transaction on the WAL.
+**
+** This routine used to be called "pagerOpenSnapshot()" because it essentially
+** makes a snapshot of the database at the current point in time and preserves
+** that snapshot for use by the reader in spite of concurrently changes by
+** other writers or checkpointers.
+*/
+static int pagerBeginReadTransaction(Pager *pPager){
+  int rc;                         /* Return code */
+  int changed = 0;                /* True if cache must be reset */
+
+  assert( pagerUseWal(pPager) );
+  assert( pPager->eState==PAGER_OPEN || pPager->eState==PAGER_READER );
+
+  /* sqlite3WalEndReadTransaction() was not called for the previous
+  ** transaction in locking_mode=EXCLUSIVE.  So call it now.  If we
+  ** are in locking_mode=NORMAL and EndRead() was previously called,
+  ** the duplicate call is harmless.
+  */
+  sqlite3WalEndReadTransaction(pPager->pWal);
+
+  rc = sqlite3WalBeginReadTransaction(pPager->pWal, &changed);
+  if( rc!=SQLITE_OK || changed ){
+    pager_reset(pPager);
+    if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);
+  }
+
+  return rc;
+}
+#endif
+
+/*
+** This function is called as part of the transition from PAGER_OPEN
+** to PAGER_READER state to determine the size of the database file
+** in pages (assuming the page size currently stored in Pager.pageSize).
+**
+** If no error occurs, SQLITE_OK is returned and the size of the database
+** in pages is stored in *pnPage. Otherwise, an error code (perhaps
+** SQLITE_IOERR_FSTAT) is returned and *pnPage is left unmodified.
+*/
+static int pagerPagecount(Pager *pPager, Pgno *pnPage){
+  Pgno nPage;                     /* Value to return via *pnPage */
+
+  /* Query the WAL sub-system for the database size. The WalDbsize()
+  ** function returns zero if the WAL is not open (i.e. Pager.pWal==0), or
+  ** if the database size is not available. The database size is not
+  ** available from the WAL sub-system if the log file is empty or
+  ** contains no valid committed transactions.
+  */
+  assert( pPager->eState==PAGER_OPEN );
+  assert( pPager->eLock>=SHARED_LOCK );
+  assert( isOpen(pPager->fd) );
+  assert( pPager->tempFile==0 );
+  nPage = sqlite3WalDbsize(pPager->pWal);
+
+  /* If the number of pages in the database is not available from the
+  ** WAL sub-system, determine the page count based on the size of
+  ** the database file.  If the size of the database file is not an
+  ** integer multiple of the page-size, round up the result.
+  */
+  if( nPage==0 && ALWAYS(isOpen(pPager->fd)) ){
+    i64 n = 0;                    /* Size of db file in bytes */
+    int rc = sqlite3OsFileSize(pPager->fd, &n);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    nPage = (Pgno)((n+pPager->pageSize-1) / pPager->pageSize);
+  }
+
+  /* If the current number of pages in the file is greater than the
+  ** configured maximum pager number, increase the allowed limit so
+  ** that the file can be read.
+  */
+  if( nPage>pPager->mxPgno ){
+    pPager->mxPgno = (Pgno)nPage;
+  }
+
+  *pnPage = nPage;
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** Check if the *-wal file that corresponds to the database opened by pPager
+** exists if the database is not empty, or verify that the *-wal file does
+** not exist (by deleting it) if the database file is empty.
+**
+** If the database is not empty and the *-wal file exists, open the pager
+** in WAL mode.  If the database is empty or if no *-wal file exists and
+** if no error occurs, make sure Pager.journalMode is not set to
+** PAGER_JOURNALMODE_WAL.
+**
+** Return SQLITE_OK or an error code.
+**
+** The caller must hold a SHARED lock on the database file to call this
+** function. Because an EXCLUSIVE lock on the db file is required to delete
+** a WAL on a none-empty database, this ensures there is no race condition
+** between the xAccess() below and an xDelete() being executed by some
+** other connection.
+*/
+static int pagerOpenWalIfPresent(Pager *pPager){
+  int rc = SQLITE_OK;
+  assert( pPager->eState==PAGER_OPEN );
+  assert( pPager->eLock>=SHARED_LOCK );
+
+  if( !pPager->tempFile ){
+    int isWal;                    /* True if WAL file exists */
+    rc = sqlite3OsAccess(
+        pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &isWal
+    );
+    if( rc==SQLITE_OK ){
+      if( isWal ){
+        Pgno nPage;                   /* Size of the database file */
+
+        rc = pagerPagecount(pPager, &nPage);
+        if( rc ) return rc;
+        if( nPage==0 ){
+          rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
+        }else{
+          testcase( sqlite3PcachePagecount(pPager->pPCache)==0 );
+          rc = sqlite3PagerOpenWal(pPager, 0);
+        }
+      }else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
+        pPager->journalMode = PAGER_JOURNALMODE_DELETE;
+      }
+    }
+  }
+  return rc;
+}
+#endif
+
+/*
+** Playback savepoint pSavepoint. Or, if pSavepoint==NULL, then playback
+** the entire super-journal file. The case pSavepoint==NULL occurs when
+** a ROLLBACK TO command is invoked on a SAVEPOINT that is a transaction
+** savepoint.
+**
+** When pSavepoint is not NULL (meaning a non-transaction savepoint is
+** being rolled back), then the rollback consists of up to three stages,
+** performed in the order specified:
+**
+**   * Pages are played back from the main journal starting at byte
+**     offset PagerSavepoint.iOffset and continuing to
+**     PagerSavepoint.iHdrOffset, or to the end of the main journal
+**     file if PagerSavepoint.iHdrOffset is zero.
+**
+**   * If PagerSavepoint.iHdrOffset is not zero, then pages are played
+**     back starting from the journal header immediately following
+**     PagerSavepoint.iHdrOffset to the end of the main journal file.
+**
+**   * Pages are then played back from the sub-journal file, starting
+**     with the PagerSavepoint.iSubRec and continuing to the end of
+**     the journal file.
+**
+** Throughout the rollback process, each time a page is rolled back, the
+** corresponding bit is set in a bitvec structure (variable pDone in the
+** implementation below). This is used to ensure that a page is only
+** rolled back the first time it is encountered in either journal.
+**
+** If pSavepoint is NULL, then pages are only played back from the main
+** journal file. There is no need for a bitvec in this case.
+**
+** In either case, before playback commences the Pager.dbSize variable
+** is reset to the value that it held at the start of the savepoint
+** (or transaction). No page with a page-number greater than this value
+** is played back. If one is encountered it is simply skipped.
+*/
+static int pagerPlaybackSavepoint(Pager *pPager, PagerSavepoint *pSavepoint){
+  i64 szJ;                 /* Effective size of the main journal */
+  i64 iHdrOff;             /* End of first segment of main-journal records */
+  int rc = SQLITE_OK;      /* Return code */
+  Bitvec *pDone = 0;       /* Bitvec to ensure pages played back only once */
+
+  assert( pPager->eState!=PAGER_ERROR );
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+
+  /* Allocate a bitvec to use to store the set of pages rolled back */
+  if( pSavepoint ){
+    pDone = sqlite3BitvecCreate(pSavepoint->nOrig);
+    if( !pDone ){
+      return SQLITE_NOMEM_BKPT;
+    }
+  }
+
+  /* Set the database size back to the value it was before the savepoint
+  ** being reverted was opened.
+  */
+  pPager->dbSize = pSavepoint ? pSavepoint->nOrig : pPager->dbOrigSize;
+  pPager->changeCountDone = pPager->tempFile;
+
+  if( !pSavepoint && pagerUseWal(pPager) ){
+    return pagerRollbackWal(pPager);
+  }
+
+  /* Use pPager->journalOff as the effective size of the main rollback
+  ** journal.  The actual file might be larger than this in
+  ** PAGER_JOURNALMODE_TRUNCATE or PAGER_JOURNALMODE_PERSIST.  But anything
+  ** past pPager->journalOff is off-limits to us.
+  */
+  szJ = pPager->journalOff;
+  assert( pagerUseWal(pPager)==0 || szJ==0 );
+
+  /* Begin by rolling back records from the main journal starting at
+  ** PagerSavepoint.iOffset and continuing to the next journal header.
+  ** There might be records in the main journal that have a page number
+  ** greater than the current database size (pPager->dbSize) but those
+  ** will be skipped automatically.  Pages are added to pDone as they
+  ** are played back.
+  */
+  if( pSavepoint && !pagerUseWal(pPager) ){
+    iHdrOff = pSavepoint->iHdrOffset ? pSavepoint->iHdrOffset : szJ;
+    pPager->journalOff = pSavepoint->iOffset;
+    while( rc==SQLITE_OK && pPager->journalOff<iHdrOff ){
+      rc = pager_playback_one_page(pPager, &pPager->journalOff, pDone, 1, 1);
+    }
+    assert( rc!=SQLITE_DONE );
+  }else{
+    pPager->journalOff = 0;
+  }
+
+  /* Continue rolling back records out of the main journal starting at
+  ** the first journal header seen and continuing until the effective end
+  ** of the main journal file.  Continue to skip out-of-range pages and
+  ** continue adding pages rolled back to pDone.
+  */
+  while( rc==SQLITE_OK && pPager->journalOff<szJ ){
+    u32 ii;            /* Loop counter */
+    u32 nJRec = 0;     /* Number of Journal Records */
+    u32 dummy;
+    rc = readJournalHdr(pPager, 0, szJ, &nJRec, &dummy);
+    assert( rc!=SQLITE_DONE );
+
+    /*
+    ** The "pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff"
+    ** test is related to ticket #2565.  See the discussion in the
+    ** pager_playback() function for additional information.
+    */
+    if( nJRec==0
+     && pPager->journalHdr+JOURNAL_HDR_SZ(pPager)==pPager->journalOff
+    ){
+      nJRec = (u32)((szJ - pPager->journalOff)/JOURNAL_PG_SZ(pPager));
+    }
+    for(ii=0; rc==SQLITE_OK && ii<nJRec && pPager->journalOff<szJ; ii++){
+      rc = pager_playback_one_page(pPager, &pPager->journalOff, pDone, 1, 1);
+    }
+    assert( rc!=SQLITE_DONE );
+  }
+  assert( rc!=SQLITE_OK || pPager->journalOff>=szJ );
+
+  /* Finally,  rollback pages from the sub-journal.  Page that were
+  ** previously rolled back out of the main journal (and are hence in pDone)
+  ** will be skipped.  Out-of-range pages are also skipped.
+  */
+  if( pSavepoint ){
+    u32 ii;            /* Loop counter */
+    i64 offset = (i64)pSavepoint->iSubRec*(4+pPager->pageSize);
+
+    if( pagerUseWal(pPager) ){
+      rc = sqlite3WalSavepointUndo(pPager->pWal, pSavepoint->aWalData);
+    }
+    for(ii=pSavepoint->iSubRec; rc==SQLITE_OK && ii<pPager->nSubRec; ii++){
+      assert( offset==(i64)ii*(4+pPager->pageSize) );
+      rc = pager_playback_one_page(pPager, &offset, pDone, 0, 1);
+    }
+    assert( rc!=SQLITE_DONE );
+  }
+
+  sqlite3BitvecDestroy(pDone);
+  if( rc==SQLITE_OK ){
+    pPager->journalOff = szJ;
+  }
+
+  return rc;
+}
+
+/*
+** Change the maximum number of in-memory pages that are allowed
+** before attempting to recycle clean and unused pages.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
+  sqlite3PcacheSetCachesize(pPager->pPCache, mxPage);
+}
+
+/*
+** Change the maximum number of in-memory pages that are allowed
+** before attempting to spill pages to journal.
+*/
+SQLITE_PRIVATE int sqlite3PagerSetSpillsize(Pager *pPager, int mxPage){
+  return sqlite3PcacheSetSpillsize(pPager->pPCache, mxPage);
+}
+
+/*
+** Invoke SQLITE_FCNTL_MMAP_SIZE based on the current value of szMmap.
+*/
+static void pagerFixMaplimit(Pager *pPager){
+#if SQLITE_MAX_MMAP_SIZE>0
+  sqlite3_file *fd = pPager->fd;
+  if( isOpen(fd) && fd->pMethods->iVersion>=3 ){
+    sqlite3_int64 sz;
+    sz = pPager->szMmap;
+    pPager->bUseFetch = (sz>0);
+    setGetterMethod(pPager);
+    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_MMAP_SIZE, &sz);
+  }
+#endif
+}
+
+/*
+** Change the maximum size of any memory mapping made of the database file.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetMmapLimit(Pager *pPager, sqlite3_int64 szMmap){
+  pPager->szMmap = szMmap;
+  pagerFixMaplimit(pPager);
+}
+
+/*
+** Free as much memory as possible from the pager.
+*/
+SQLITE_PRIVATE void sqlite3PagerShrink(Pager *pPager){
+  sqlite3PcacheShrink(pPager->pPCache);
+}
+
+/*
+** Adjust settings of the pager to those specified in the pgFlags parameter.
+**
+** The "level" in pgFlags & PAGER_SYNCHRONOUS_MASK sets the robustness
+** of the database to damage due to OS crashes or power failures by
+** changing the number of syncs()s when writing the journals.
+** There are four levels:
+**
+**    OFF       sqlite3OsSync() is never called.  This is the default
+**              for temporary and transient files.
+**
+**    NORMAL    The journal is synced once before writes begin on the
+**              database.  This is normally adequate protection, but
+**              it is theoretically possible, though very unlikely,
+**              that an inopertune power failure could leave the journal
+**              in a state which would cause damage to the database
+**              when it is rolled back.
+**
+**    FULL      The journal is synced twice before writes begin on the
+**              database (with some additional information - the nRec field
+**              of the journal header - being written in between the two
+**              syncs).  If we assume that writing a
+**              single disk sector is atomic, then this mode provides
+**              assurance that the journal will not be corrupted to the
+**              point of causing damage to the database during rollback.
+**
+**    EXTRA     This is like FULL except that is also syncs the directory
+**              that contains the rollback journal after the rollback
+**              journal is unlinked.
+**
+** The above is for a rollback-journal mode.  For WAL mode, OFF continues
+** to mean that no syncs ever occur.  NORMAL means that the WAL is synced
+** prior to the start of checkpoint and that the database file is synced
+** at the conclusion of the checkpoint if the entire content of the WAL
+** was written back into the database.  But no sync operations occur for
+** an ordinary commit in NORMAL mode with WAL.  FULL means that the WAL
+** file is synced following each commit operation, in addition to the
+** syncs associated with NORMAL.  There is no difference between FULL
+** and EXTRA for WAL mode.
+**
+** Do not confuse synchronous=FULL with SQLITE_SYNC_FULL.  The
+** SQLITE_SYNC_FULL macro means to use the MacOSX-style full-fsync
+** using fcntl(F_FULLFSYNC).  SQLITE_SYNC_NORMAL means to do an
+** ordinary fsync() call.  There is no difference between SQLITE_SYNC_FULL
+** and SQLITE_SYNC_NORMAL on platforms other than MacOSX.  But the
+** synchronous=FULL versus synchronous=NORMAL setting determines when
+** the xSync primitive is called and is relevant to all platforms.
+**
+** Numeric values associated with these states are OFF==1, NORMAL=2,
+** and FULL=3.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetFlags(
+  Pager *pPager,        /* The pager to set safety level for */
+  unsigned pgFlags      /* Various flags */
+){
+  unsigned level = pgFlags & PAGER_SYNCHRONOUS_MASK;
+  if( pPager->tempFile ){
+    pPager->noSync = 1;
+    pPager->fullSync = 0;
+    pPager->extraSync = 0;
+  }else{
+    pPager->noSync =  level==PAGER_SYNCHRONOUS_OFF ?1:0;
+    pPager->fullSync = level>=PAGER_SYNCHRONOUS_FULL ?1:0;
+    pPager->extraSync = level==PAGER_SYNCHRONOUS_EXTRA ?1:0;
+  }
+  if( pPager->noSync ){
+    pPager->syncFlags = 0;
+  }else if( pgFlags & PAGER_FULLFSYNC ){
+    pPager->syncFlags = SQLITE_SYNC_FULL;
+  }else{
+    pPager->syncFlags = SQLITE_SYNC_NORMAL;
+  }
+  pPager->walSyncFlags = (pPager->syncFlags<<2);
+  if( pPager->fullSync ){
+    pPager->walSyncFlags |= pPager->syncFlags;
+  }
+  if( (pgFlags & PAGER_CKPT_FULLFSYNC) && !pPager->noSync ){
+    pPager->walSyncFlags |= (SQLITE_SYNC_FULL<<2);
+  }
+  if( pgFlags & PAGER_CACHESPILL ){
+    pPager->doNotSpill &= ~SPILLFLAG_OFF;
+  }else{
+    pPager->doNotSpill |= SPILLFLAG_OFF;
+  }
+}
+
+/*
+** The following global variable is incremented whenever the library
+** attempts to open a temporary file.  This information is used for
+** testing and analysis only.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_opentemp_count = 0;
+#endif
+
+/*
+** Open a temporary file.
+**
+** Write the file descriptor into *pFile. Return SQLITE_OK on success
+** or some other error code if we fail. The OS will automatically
+** delete the temporary file when it is closed.
+**
+** The flags passed to the VFS layer xOpen() call are those specified
+** by parameter vfsFlags ORed with the following:
+**
+**     SQLITE_OPEN_READWRITE
+**     SQLITE_OPEN_CREATE
+**     SQLITE_OPEN_EXCLUSIVE
+**     SQLITE_OPEN_DELETEONCLOSE
+*/
+static int pagerOpentemp(
+  Pager *pPager,        /* The pager object */
+  sqlite3_file *pFile,  /* Write the file descriptor here */
+  int vfsFlags          /* Flags passed through to the VFS */
+){
+  int rc;               /* Return code */
+
+#ifdef SQLITE_TEST
+  sqlite3_opentemp_count++;  /* Used for testing and analysis only */
+#endif
+
+  vfsFlags |=  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
+            SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE;
+  rc = sqlite3OsOpen(pPager->pVfs, 0, pFile, vfsFlags, 0);
+  assert( rc!=SQLITE_OK || isOpen(pFile) );
+  return rc;
+}
+
+/*
+** Set the busy handler function.
+**
+** The pager invokes the busy-handler if sqlite3OsLock() returns
+** SQLITE_BUSY when trying to upgrade from no-lock to a SHARED lock,
+** or when trying to upgrade from a RESERVED lock to an EXCLUSIVE
+** lock. It does *not* invoke the busy handler when upgrading from
+** SHARED to RESERVED, or when upgrading from SHARED to EXCLUSIVE
+** (which occurs during hot-journal rollback). Summary:
+**
+**   Transition                        | Invokes xBusyHandler
+**   --------------------------------------------------------
+**   NO_LOCK       -> SHARED_LOCK      | Yes
+**   SHARED_LOCK   -> RESERVED_LOCK    | No
+**   SHARED_LOCK   -> EXCLUSIVE_LOCK   | No
+**   RESERVED_LOCK -> EXCLUSIVE_LOCK   | Yes
+**
+** If the busy-handler callback returns non-zero, the lock is
+** retried. If it returns zero, then the SQLITE_BUSY error is
+** returned to the caller of the pager API function.
+*/
+SQLITE_PRIVATE void sqlite3PagerSetBusyHandler(
+  Pager *pPager,                       /* Pager object */
+  int (*xBusyHandler)(void *),         /* Pointer to busy-handler function */
+  void *pBusyHandlerArg                /* Argument to pass to xBusyHandler */
+){
+  void **ap;
+  pPager->xBusyHandler = xBusyHandler;
+  pPager->pBusyHandlerArg = pBusyHandlerArg;
+  ap = (void **)&pPager->xBusyHandler;
+  assert( ((int(*)(void *))(ap[0]))==xBusyHandler );
+  assert( ap[1]==pBusyHandlerArg );
+  sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_BUSYHANDLER, (void *)ap);
+}
+
+/*
+** Change the page size used by the Pager object. The new page size
+** is passed in *pPageSize.
+**
+** If the pager is in the error state when this function is called, it
+** is a no-op. The value returned is the error state error code (i.e.
+** one of SQLITE_IOERR, an SQLITE_IOERR_xxx sub-code or SQLITE_FULL).
+**
+** Otherwise, if all of the following are true:
+**
+**   * the new page size (value of *pPageSize) is valid (a power
+**     of two between 512 and SQLITE_MAX_PAGE_SIZE, inclusive), and
+**
+**   * there are no outstanding page references, and
+**
+**   * the database is either not an in-memory database or it is
+**     an in-memory database that currently consists of zero pages.
+**
+** then the pager object page size is set to *pPageSize.
+**
+** If the page size is changed, then this function uses sqlite3PagerMalloc()
+** to obtain a new Pager.pTmpSpace buffer. If this allocation attempt
+** fails, SQLITE_NOMEM is returned and the page size remains unchanged.
+** In all other cases, SQLITE_OK is returned.
+**
+** If the page size is not changed, either because one of the enumerated
+** conditions above is not true, the pager was in error state when this
+** function was called, or because the memory allocation attempt failed,
+** then *pPageSize is set to the old, retained page size before returning.
+*/
+SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager *pPager, u32 *pPageSize, int nReserve){
+  int rc = SQLITE_OK;
+
+  /* It is not possible to do a full assert_pager_state() here, as this
+  ** function may be called from within PagerOpen(), before the state
+  ** of the Pager object is internally consistent.
+  **
+  ** At one point this function returned an error if the pager was in
+  ** PAGER_ERROR state. But since PAGER_ERROR state guarantees that
+  ** there is at least one outstanding page reference, this function
+  ** is a no-op for that case anyhow.
+  */
+
+  u32 pageSize = *pPageSize;
+  assert( pageSize==0 || (pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE) );
+  if( (pPager->memDb==0 || pPager->dbSize==0)
+   && sqlite3PcacheRefCount(pPager->pPCache)==0
+   && pageSize && pageSize!=(u32)pPager->pageSize
+  ){
+    char *pNew = NULL;             /* New temp space */
+    i64 nByte = 0;
+
+    if( pPager->eState>PAGER_OPEN && isOpen(pPager->fd) ){
+      rc = sqlite3OsFileSize(pPager->fd, &nByte);
+    }
+    if( rc==SQLITE_OK ){
+      /* 8 bytes of zeroed overrun space is sufficient so that the b-tree
+      * cell header parser will never run off the end of the allocation */
+      pNew = (char *)sqlite3PageMalloc(pageSize+8);
+      if( !pNew ){
+        rc = SQLITE_NOMEM_BKPT;
+      }else{
+        memset(pNew+pageSize, 0, 8);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      pager_reset(pPager);
+      rc = sqlite3PcacheSetPageSize(pPager->pPCache, pageSize);
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3PageFree(pPager->pTmpSpace);
+      pPager->pTmpSpace = pNew;
+      pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize);
+      pPager->pageSize = pageSize;
+      pPager->lckPgno = (Pgno)(PENDING_BYTE/pageSize) + 1;
+    }else{
+      sqlite3PageFree(pNew);
+    }
+  }
+
+  *pPageSize = pPager->pageSize;
+  if( rc==SQLITE_OK ){
+    if( nReserve<0 ) nReserve = pPager->nReserve;
+    assert( nReserve>=0 && nReserve<1000 );
+    pPager->nReserve = (i16)nReserve;
+    pagerFixMaplimit(pPager);
+  }
+  return rc;
+}
+
+/*
+** Return a pointer to the "temporary page" buffer held internally
+** by the pager.  This is a buffer that is big enough to hold the
+** entire content of a database page.  This buffer is used internally
+** during rollback and will be overwritten whenever a rollback
+** occurs.  But other modules are free to use it too, as long as
+** no rollbacks are happening.
+*/
+SQLITE_PRIVATE void *sqlite3PagerTempSpace(Pager *pPager){
+  return pPager->pTmpSpace;
+}
+
+/*
+** Attempt to set the maximum database page count if mxPage is positive.
+** Make no changes if mxPage is zero or negative.  And never reduce the
+** maximum page count below the current size of the database.
+**
+** Regardless of mxPage, return the current maximum page count.
+*/
+SQLITE_PRIVATE Pgno sqlite3PagerMaxPageCount(Pager *pPager, Pgno mxPage){
+  if( mxPage>0 ){
+    pPager->mxPgno = mxPage;
+  }
+  assert( pPager->eState!=PAGER_OPEN );      /* Called only by OP_MaxPgcnt */
+  /* assert( pPager->mxPgno>=pPager->dbSize ); */
+  /* OP_MaxPgcnt ensures that the parameter passed to this function is not
+  ** less than the total number of valid pages in the database. But this
+  ** may be less than Pager.dbSize, and so the assert() above is not valid */
+  return pPager->mxPgno;
+}
+
+/*
+** The following set of routines are used to disable the simulated
+** I/O error mechanism.  These routines are used to avoid simulated
+** errors in places where we do not care about errors.
+**
+** Unless -DSQLITE_TEST=1 is used, these routines are all no-ops
+** and generate no code.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API extern int sqlite3_io_error_pending;
+SQLITE_API extern int sqlite3_io_error_hit;
+static int saved_cnt;
+void disable_simulated_io_errors(void){
+  saved_cnt = sqlite3_io_error_pending;
+  sqlite3_io_error_pending = -1;
+}
+void enable_simulated_io_errors(void){
+  sqlite3_io_error_pending = saved_cnt;
+}
+#else
+# define disable_simulated_io_errors()
+# define enable_simulated_io_errors()
+#endif
+
+/*
+** Read the first N bytes from the beginning of the file into memory
+** that pDest points to.
+**
+** If the pager was opened on a transient file (zFilename==""), or
+** opened on a file less than N bytes in size, the output buffer is
+** zeroed and SQLITE_OK returned. The rationale for this is that this
+** function is used to read database headers, and a new transient or
+** zero sized database has a header than consists entirely of zeroes.
+**
+** If any IO error apart from SQLITE_IOERR_SHORT_READ is encountered,
+** the error code is returned to the caller and the contents of the
+** output buffer undefined.
+*/
+SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
+  int rc = SQLITE_OK;
+  memset(pDest, 0, N);
+  assert( isOpen(pPager->fd) || pPager->tempFile );
+
+  /* This routine is only called by btree immediately after creating
+  ** the Pager object.  There has not been an opportunity to transition
+  ** to WAL mode yet.
+  */
+  assert( !pagerUseWal(pPager) );
+
+  if( isOpen(pPager->fd) ){
+    IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
+    rc = sqlite3OsRead(pPager->fd, pDest, N, 0);
+    if( rc==SQLITE_IOERR_SHORT_READ ){
+      rc = SQLITE_OK;
+    }
+  }
+  return rc;
+}
+
+/*
+** This function may only be called when a read-transaction is open on
+** the pager. It returns the total number of pages in the database.
+**
+** However, if the file is between 1 and <page-size> bytes in size, then
+** this is considered a 1 page file.
+*/
+SQLITE_PRIVATE void sqlite3PagerPagecount(Pager *pPager, int *pnPage){
+  assert( pPager->eState>=PAGER_READER );
+  assert( pPager->eState!=PAGER_WRITER_FINISHED );
+  *pnPage = (int)pPager->dbSize;
+}
+
+
+/*
+** Try to obtain a lock of type locktype on the database file. If
+** a similar or greater lock is already held, this function is a no-op
+** (returning SQLITE_OK immediately).
+**
+** Otherwise, attempt to obtain the lock using sqlite3OsLock(). Invoke
+** the busy callback if the lock is currently not available. Repeat
+** until the busy callback returns false or until the attempt to
+** obtain the lock succeeds.
+**
+** Return SQLITE_OK on success and an error code if we cannot obtain
+** the lock. If the lock is obtained successfully, set the Pager.state
+** variable to locktype before returning.
+*/
+static int pager_wait_on_lock(Pager *pPager, int locktype){
+  int rc;                              /* Return code */
+
+  /* Check that this is either a no-op (because the requested lock is
+  ** already held), or one of the transitions that the busy-handler
+  ** may be invoked during, according to the comment above
+  ** sqlite3PagerSetBusyhandler().
+  */
+  assert( (pPager->eLock>=locktype)
+       || (pPager->eLock==NO_LOCK && locktype==SHARED_LOCK)
+       || (pPager->eLock==RESERVED_LOCK && locktype==EXCLUSIVE_LOCK)
+  );
+
+  do {
+    rc = pagerLockDb(pPager, locktype);
+  }while( rc==SQLITE_BUSY && pPager->xBusyHandler(pPager->pBusyHandlerArg) );
+  return rc;
+}
+
+/*
+** Function assertTruncateConstraint(pPager) checks that one of the
+** following is true for all dirty pages currently in the page-cache:
+**
+**   a) The page number is less than or equal to the size of the
+**      current database image, in pages, OR
+**
+**   b) if the page content were written at this time, it would not
+**      be necessary to write the current content out to the sub-journal.
+**
+** If the condition asserted by this function were not true, and the
+** dirty page were to be discarded from the cache via the pagerStress()
+** routine, pagerStress() would not write the current page content to
+** the database file. If a savepoint transaction were rolled back after
+** this happened, the correct behavior would be to restore the current
+** content of the page. However, since this content is not present in either
+** the database file or the portion of the rollback journal and
+** sub-journal rolled back the content could not be restored and the
+** database image would become corrupt. It is therefore fortunate that
+** this circumstance cannot arise.
+*/
+#if defined(SQLITE_DEBUG)
+static void assertTruncateConstraintCb(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  assert( pPg->flags&PGHDR_DIRTY );
+  if( pPg->pgno>pPager->dbSize ){      /* if (a) is false */
+    Pgno pgno = pPg->pgno;
+    int i;
+    for(i=0; i<pPg->pPager->nSavepoint; i++){
+      PagerSavepoint *p = &pPager->aSavepoint[i];
+      assert( p->nOrig<pgno || sqlite3BitvecTestNotNull(p->pInSavepoint,pgno) );
+    }
+  }
+}
+static void assertTruncateConstraint(Pager *pPager){
+  sqlite3PcacheIterateDirty(pPager->pPCache, assertTruncateConstraintCb);
+}
+#else
+# define assertTruncateConstraint(pPager)
+#endif
+
+/*
+** Truncate the in-memory database file image to nPage pages. This
+** function does not actually modify the database file on disk. It
+** just sets the internal state of the pager object so that the
+** truncation will be done when the current transaction is committed.
+**
+** This function is only called right before committing a transaction.
+** Once this function has been called, the transaction must either be
+** rolled back or committed. It is not safe to call this function and
+** then continue writing to the database.
+*/
+SQLITE_PRIVATE void sqlite3PagerTruncateImage(Pager *pPager, Pgno nPage){
+  assert( pPager->dbSize>=nPage || CORRUPT_DB );
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD );
+  pPager->dbSize = nPage;
+
+  /* At one point the code here called assertTruncateConstraint() to
+  ** ensure that all pages being truncated away by this operation are,
+  ** if one or more savepoints are open, present in the savepoint
+  ** journal so that they can be restored if the savepoint is rolled
+  ** back. This is no longer necessary as this function is now only
+  ** called right before committing a transaction. So although the
+  ** Pager object may still have open savepoints (Pager.nSavepoint!=0),
+  ** they cannot be rolled back. So the assertTruncateConstraint() call
+  ** is no longer correct. */
+}
+
+
+/*
+** This function is called before attempting a hot-journal rollback. It
+** syncs the journal file to disk, then sets pPager->journalHdr to the
+** size of the journal file so that the pager_playback() routine knows
+** that the entire journal file has been synced.
+**
+** Syncing a hot-journal to disk before attempting to roll it back ensures
+** that if a power-failure occurs during the rollback, the process that
+** attempts rollback following system recovery sees the same journal
+** content as this process.
+**
+** If everything goes as planned, SQLITE_OK is returned. Otherwise,
+** an SQLite error code.
+*/
+static int pagerSyncHotJournal(Pager *pPager){
+  int rc = SQLITE_OK;
+  if( !pPager->noSync ){
+    rc = sqlite3OsSync(pPager->jfd, SQLITE_SYNC_NORMAL);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3OsFileSize(pPager->jfd, &pPager->journalHdr);
+  }
+  return rc;
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/*
+** Obtain a reference to a memory mapped page object for page number pgno.
+** The new object will use the pointer pData, obtained from xFetch().
+** If successful, set *ppPage to point to the new page reference
+** and return SQLITE_OK. Otherwise, return an SQLite error code and set
+** *ppPage to zero.
+**
+** Page references obtained by calling this function should be released
+** by calling pagerReleaseMapPage().
+*/
+static int pagerAcquireMapPage(
+  Pager *pPager,                  /* Pager object */
+  Pgno pgno,                      /* Page number */
+  void *pData,                    /* xFetch()'d data for this page */
+  PgHdr **ppPage                  /* OUT: Acquired page object */
+){
+  PgHdr *p;                       /* Memory mapped page to return */
+
+  if( pPager->pMmapFreelist ){
+    *ppPage = p = pPager->pMmapFreelist;
+    pPager->pMmapFreelist = p->pDirty;
+    p->pDirty = 0;
+    assert( pPager->nExtra>=8 );
+    memset(p->pExtra, 0, 8);
+  }else{
+    *ppPage = p = (PgHdr *)sqlite3MallocZero(sizeof(PgHdr) + pPager->nExtra);
+    if( p==0 ){
+      sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1) * pPager->pageSize, pData);
+      return SQLITE_NOMEM_BKPT;
+    }
+    p->pExtra = (void *)&p[1];
+    assert( EIGHT_BYTE_ALIGNMENT( p->pExtra ) );
+    p->flags = PGHDR_MMAP;
+    p->nRef = 1;
+    p->pPager = pPager;
+  }
+
+  assert( p->pExtra==(void *)&p[1] );
+  assert( p->pPage==0 );
+  assert( p->flags==PGHDR_MMAP );
+  assert( p->pPager==pPager );
+  assert( p->nRef==1 );
+
+  p->pgno = pgno;
+  p->pData = pData;
+  pPager->nMmapOut++;
+
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Release a reference to page pPg. pPg must have been returned by an
+** earlier call to pagerAcquireMapPage().
+*/
+static void pagerReleaseMapPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  pPager->nMmapOut--;
+  pPg->pDirty = pPager->pMmapFreelist;
+  pPager->pMmapFreelist = pPg;
+
+  assert( pPager->fd->pMethods->iVersion>=3 );
+  sqlite3OsUnfetch(pPager->fd, (i64)(pPg->pgno-1)*pPager->pageSize, pPg->pData);
+}
+
+/*
+** Free all PgHdr objects stored in the Pager.pMmapFreelist list.
+*/
+static void pagerFreeMapHdrs(Pager *pPager){
+  PgHdr *p;
+  PgHdr *pNext;
+  for(p=pPager->pMmapFreelist; p; p=pNext){
+    pNext = p->pDirty;
+    sqlite3_free(p);
+  }
+}
+
+/* Verify that the database file has not be deleted or renamed out from
+** under the pager.  Return SQLITE_OK if the database is still where it ought
+** to be on disk.  Return non-zero (SQLITE_READONLY_DBMOVED or some other error
+** code from sqlite3OsAccess()) if the database has gone missing.
+*/
+static int databaseIsUnmoved(Pager *pPager){
+  int bHasMoved = 0;
+  int rc;
+
+  if( pPager->tempFile ) return SQLITE_OK;
+  if( pPager->dbSize==0 ) return SQLITE_OK;
+  assert( pPager->zFilename && pPager->zFilename[0] );
+  rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_HAS_MOVED, &bHasMoved);
+  if( rc==SQLITE_NOTFOUND ){
+    /* If the HAS_MOVED file-control is unimplemented, assume that the file
+    ** has not been moved.  That is the historical behavior of SQLite: prior to
+    ** version 3.8.3, it never checked */
+    rc = SQLITE_OK;
+  }else if( rc==SQLITE_OK && bHasMoved ){
+    rc = SQLITE_READONLY_DBMOVED;
+  }
+  return rc;
+}
+
+
+/*
+** Shutdown the page cache.  Free all memory and close all files.
+**
+** If a transaction was in progress when this routine is called, that
+** transaction is rolled back.  All outstanding pages are invalidated
+** and their memory is freed.  Any attempt to use a page associated
+** with this page cache after this function returns will likely
+** result in a coredump.
+**
+** This function always succeeds. If a transaction is active an attempt
+** is made to roll it back. If an error occurs during the rollback
+** a hot journal may be left in the filesystem but no error is returned
+** to the caller.
+*/
+SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager, sqlite3 *db){
+  u8 *pTmp = (u8*)pPager->pTmpSpace;
+  assert( db || pagerUseWal(pPager)==0 );
+  assert( assert_pager_state(pPager) );
+  disable_simulated_io_errors();
+  sqlite3BeginBenignMalloc();
+  pagerFreeMapHdrs(pPager);
+  /* pPager->errCode = 0; */
+  pPager->exclusiveMode = 0;
+#ifndef SQLITE_OMIT_WAL
+  {
+    u8 *a = 0;
+    assert( db || pPager->pWal==0 );
+    if( db && 0==(db->flags & SQLITE_NoCkptOnClose)
+     && SQLITE_OK==databaseIsUnmoved(pPager)
+    ){
+      a = pTmp;
+    }
+    sqlite3WalClose(pPager->pWal, db, pPager->walSyncFlags, pPager->pageSize,a);
+    pPager->pWal = 0;
+  }
+#endif
+  pager_reset(pPager);
+  if( MEMDB ){
+    pager_unlock(pPager);
+  }else{
+    /* If it is open, sync the journal file before calling UnlockAndRollback.
+    ** If this is not done, then an unsynced portion of the open journal
+    ** file may be played back into the database. If a power failure occurs
+    ** while this is happening, the database could become corrupt.
+    **
+    ** If an error occurs while trying to sync the journal, shift the pager
+    ** into the ERROR state. This causes UnlockAndRollback to unlock the
+    ** database and close the journal file without attempting to roll it
+    ** back or finalize it. The next database user will have to do hot-journal
+    ** rollback before accessing the database file.
+    */
+    if( isOpen(pPager->jfd) ){
+      pager_error(pPager, pagerSyncHotJournal(pPager));
+    }
+    pagerUnlockAndRollback(pPager);
+  }
+  sqlite3EndBenignMalloc();
+  enable_simulated_io_errors();
+  PAGERTRACE(("CLOSE %d\n", PAGERID(pPager)));
+  IOTRACE(("CLOSE %p\n", pPager))
+  sqlite3OsClose(pPager->jfd);
+  sqlite3OsClose(pPager->fd);
+  sqlite3PageFree(pTmp);
+  sqlite3PcacheClose(pPager->pPCache);
+  assert( !pPager->aSavepoint && !pPager->pInJournal );
+  assert( !isOpen(pPager->jfd) && !isOpen(pPager->sjfd) );
+
+  sqlite3_free(pPager);
+  return SQLITE_OK;
+}
+
+#if !defined(NDEBUG) || defined(SQLITE_TEST)
+/*
+** Return the page number for page pPg.
+*/
+SQLITE_PRIVATE Pgno sqlite3PagerPagenumber(DbPage *pPg){
+  return pPg->pgno;
+}
+#endif
+
+/*
+** Increment the reference count for page pPg.
+*/
+SQLITE_PRIVATE void sqlite3PagerRef(DbPage *pPg){
+  sqlite3PcacheRef(pPg);
+}
+
+/*
+** Sync the journal. In other words, make sure all the pages that have
+** been written to the journal have actually reached the surface of the
+** disk and can be restored in the event of a hot-journal rollback.
+**
+** If the Pager.noSync flag is set, then this function is a no-op.
+** Otherwise, the actions required depend on the journal-mode and the
+** device characteristics of the file-system, as follows:
+**
+**   * If the journal file is an in-memory journal file, no action need
+**     be taken.
+**
+**   * Otherwise, if the device does not support the SAFE_APPEND property,
+**     then the nRec field of the most recently written journal header
+**     is updated to contain the number of journal records that have
+**     been written following it. If the pager is operating in full-sync
+**     mode, then the journal file is synced before this field is updated.
+**
+**   * If the device does not support the SEQUENTIAL property, then
+**     journal file is synced.
+**
+** Or, in pseudo-code:
+**
+**   if( NOT <in-memory journal> ){
+**     if( NOT SAFE_APPEND ){
+**       if( <full-sync mode> ) xSync(<journal file>);
+**       <update nRec field>
+**     }
+**     if( NOT SEQUENTIAL ) xSync(<journal file>);
+**   }
+**
+** If successful, this routine clears the PGHDR_NEED_SYNC flag of every
+** page currently held in memory before returning SQLITE_OK. If an IO
+** error is encountered, then the IO error code is returned to the caller.
+*/
+static int syncJournal(Pager *pPager, int newHdr){
+  int rc;                         /* Return code */
+
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+  assert( !pagerUseWal(pPager) );
+
+  rc = sqlite3PagerExclusiveLock(pPager);
+  if( rc!=SQLITE_OK ) return rc;
+
+  if( !pPager->noSync ){
+    assert( !pPager->tempFile );
+    if( isOpen(pPager->jfd) && pPager->journalMode!=PAGER_JOURNALMODE_MEMORY ){
+      const int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
+      assert( isOpen(pPager->jfd) );
+
+      if( 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
+        /* This block deals with an obscure problem. If the last connection
+        ** that wrote to this database was operating in persistent-journal
+        ** mode, then the journal file may at this point actually be larger
+        ** than Pager.journalOff bytes. If the next thing in the journal
+        ** file happens to be a journal-header (written as part of the
+        ** previous connection's transaction), and a crash or power-failure
+        ** occurs after nRec is updated but before this connection writes
+        ** anything else to the journal file (or commits/rolls back its
+        ** transaction), then SQLite may become confused when doing the
+        ** hot-journal rollback following recovery. It may roll back all
+        ** of this connections data, then proceed to rolling back the old,
+        ** out-of-date data that follows it. Database corruption.
+        **
+        ** To work around this, if the journal file does appear to contain
+        ** a valid header following Pager.journalOff, then write a 0x00
+        ** byte to the start of it to prevent it from being recognized.
+        **
+        ** Variable iNextHdrOffset is set to the offset at which this
+        ** problematic header will occur, if it exists. aMagic is used
+        ** as a temporary buffer to inspect the first couple of bytes of
+        ** the potential journal header.
+        */
+        i64 iNextHdrOffset;
+        u8 aMagic[8];
+        u8 zHeader[sizeof(aJournalMagic)+4];
+
+        memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
+        put32bits(&zHeader[sizeof(aJournalMagic)], pPager->nRec);
+
+        iNextHdrOffset = journalHdrOffset(pPager);
+        rc = sqlite3OsRead(pPager->jfd, aMagic, 8, iNextHdrOffset);
+        if( rc==SQLITE_OK && 0==memcmp(aMagic, aJournalMagic, 8) ){
+          static const u8 zerobyte = 0;
+          rc = sqlite3OsWrite(pPager->jfd, &zerobyte, 1, iNextHdrOffset);
+        }
+        if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
+          return rc;
+        }
+
+        /* Write the nRec value into the journal file header. If in
+        ** full-synchronous mode, sync the journal first. This ensures that
+        ** all data has really hit the disk before nRec is updated to mark
+        ** it as a candidate for rollback.
+        **
+        ** This is not required if the persistent media supports the
+        ** SAFE_APPEND property. Because in this case it is not possible
+        ** for garbage data to be appended to the file, the nRec field
+        ** is populated with 0xFFFFFFFF when the journal header is written
+        ** and never needs to be updated.
+        */
+        if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
+          PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
+          IOTRACE(("JSYNC %p\n", pPager))
+          rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags);
+          if( rc!=SQLITE_OK ) return rc;
+        }
+        IOTRACE(("JHDR %p %lld\n", pPager, pPager->journalHdr));
+        rc = sqlite3OsWrite(
+            pPager->jfd, zHeader, sizeof(zHeader), pPager->journalHdr
+        );
+        if( rc!=SQLITE_OK ) return rc;
+      }
+      if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
+        PAGERTRACE(("SYNC journal of %d\n", PAGERID(pPager)));
+        IOTRACE(("JSYNC %p\n", pPager))
+        rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags|
+          (pPager->syncFlags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
+        );
+        if( rc!=SQLITE_OK ) return rc;
+      }
+
+      pPager->journalHdr = pPager->journalOff;
+      if( newHdr && 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
+        pPager->nRec = 0;
+        rc = writeJournalHdr(pPager);
+        if( rc!=SQLITE_OK ) return rc;
+      }
+    }else{
+      pPager->journalHdr = pPager->journalOff;
+    }
+  }
+
+  /* Unless the pager is in noSync mode, the journal file was just
+  ** successfully synced. Either way, clear the PGHDR_NEED_SYNC flag on
+  ** all pages.
+  */
+  sqlite3PcacheClearSyncFlags(pPager->pPCache);
+  pPager->eState = PAGER_WRITER_DBMOD;
+  assert( assert_pager_state(pPager) );
+  return SQLITE_OK;
+}
+
+/*
+** The argument is the first in a linked list of dirty pages connected
+** by the PgHdr.pDirty pointer. This function writes each one of the
+** in-memory pages in the list to the database file. The argument may
+** be NULL, representing an empty list. In this case this function is
+** a no-op.
+**
+** The pager must hold at least a RESERVED lock when this function
+** is called. Before writing anything to the database file, this lock
+** is upgraded to an EXCLUSIVE lock. If the lock cannot be obtained,
+** SQLITE_BUSY is returned and no data is written to the database file.
+**
+** If the pager is a temp-file pager and the actual file-system file
+** is not yet open, it is created and opened before any data is
+** written out.
+**
+** Once the lock has been upgraded and, if necessary, the file opened,
+** the pages are written out to the database file in list order. Writing
+** a page is skipped if it meets either of the following criteria:
+**
+**   * The page number is greater than Pager.dbSize, or
+**   * The PGHDR_DONT_WRITE flag is set on the page.
+**
+** If writing out a page causes the database file to grow, Pager.dbFileSize
+** is updated accordingly. If page 1 is written out, then the value cached
+** in Pager.dbFileVers[] is updated to match the new value stored in
+** the database file.
+**
+** If everything is successful, SQLITE_OK is returned. If an IO error
+** occurs, an IO error code is returned. Or, if the EXCLUSIVE lock cannot
+** be obtained, SQLITE_BUSY is returned.
+*/
+static int pager_write_pagelist(Pager *pPager, PgHdr *pList){
+  int rc = SQLITE_OK;                  /* Return code */
+
+  /* This function is only called for rollback pagers in WRITER_DBMOD state. */
+  assert( !pagerUseWal(pPager) );
+  assert( pPager->tempFile || pPager->eState==PAGER_WRITER_DBMOD );
+  assert( pPager->eLock==EXCLUSIVE_LOCK );
+  assert( isOpen(pPager->fd) || pList->pDirty==0 );
+
+  /* If the file is a temp-file has not yet been opened, open it now. It
+  ** is not possible for rc to be other than SQLITE_OK if this branch
+  ** is taken, as pager_wait_on_lock() is a no-op for temp-files.
+  */
+  if( !isOpen(pPager->fd) ){
+    assert( pPager->tempFile && rc==SQLITE_OK );
+    rc = pagerOpentemp(pPager, pPager->fd, pPager->vfsFlags);
+  }
+
+  /* Before the first write, give the VFS a hint of what the final
+  ** file size will be.
+  */
+  assert( rc!=SQLITE_OK || isOpen(pPager->fd) );
+  if( rc==SQLITE_OK
+   && pPager->dbHintSize<pPager->dbSize
+   && (pList->pDirty || pList->pgno>pPager->dbHintSize)
+  ){
+    sqlite3_int64 szFile = pPager->pageSize * (sqlite3_int64)pPager->dbSize;
+    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);
+    pPager->dbHintSize = pPager->dbSize;
+  }
+
+  while( rc==SQLITE_OK && pList ){
+    Pgno pgno = pList->pgno;
+
+    /* If there are dirty pages in the page cache with page numbers greater
+    ** than Pager.dbSize, this means sqlite3PagerTruncateImage() was called to
+    ** make the file smaller (presumably by auto-vacuum code). Do not write
+    ** any such pages to the file.
+    **
+    ** Also, do not write out any page that has the PGHDR_DONT_WRITE flag
+    ** set (set by sqlite3PagerDontWrite()).
+    */
+    if( pgno<=pPager->dbSize && 0==(pList->flags&PGHDR_DONT_WRITE) ){
+      i64 offset = (pgno-1)*(i64)pPager->pageSize;   /* Offset to write */
+      char *pData;                                   /* Data to write */
+
+      assert( (pList->flags&PGHDR_NEED_SYNC)==0 );
+      if( pList->pgno==1 ) pager_write_changecounter(pList);
+
+      pData = pList->pData;
+
+      /* Write out the page data. */
+      rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize, offset);
+
+      /* If page 1 was just written, update Pager.dbFileVers to match
+      ** the value now stored in the database file. If writing this
+      ** page caused the database file to grow, update dbFileSize.
+      */
+      if( pgno==1 ){
+        memcpy(&pPager->dbFileVers, &pData[24], sizeof(pPager->dbFileVers));
+      }
+      if( pgno>pPager->dbFileSize ){
+        pPager->dbFileSize = pgno;
+      }
+      pPager->aStat[PAGER_STAT_WRITE]++;
+
+      /* Update any backup objects copying the contents of this pager. */
+      sqlite3BackupUpdate(pPager->pBackup, pgno, (u8*)pList->pData);
+
+      PAGERTRACE(("STORE %d page %d hash(%08x)\n",
+                   PAGERID(pPager), pgno, pager_pagehash(pList)));
+      IOTRACE(("PGOUT %p %d\n", pPager, pgno));
+      PAGER_INCR(sqlite3_pager_writedb_count);
+    }else{
+      PAGERTRACE(("NOSTORE %d page %d\n", PAGERID(pPager), pgno));
+    }
+    pager_set_pagehash(pList);
+    pList = pList->pDirty;
+  }
+
+  return rc;
+}
+
+/*
+** Ensure that the sub-journal file is open. If it is already open, this
+** function is a no-op.
+**
+** SQLITE_OK is returned if everything goes according to plan. An
+** SQLITE_IOERR_XXX error code is returned if a call to sqlite3OsOpen()
+** fails.
+*/
+static int openSubJournal(Pager *pPager){
+  int rc = SQLITE_OK;
+  if( !isOpen(pPager->sjfd) ){
+    const int flags =  SQLITE_OPEN_SUBJOURNAL | SQLITE_OPEN_READWRITE
+      | SQLITE_OPEN_CREATE | SQLITE_OPEN_EXCLUSIVE
+      | SQLITE_OPEN_DELETEONCLOSE;
+    int nStmtSpill = sqlite3Config.nStmtSpill;
+    if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY || pPager->subjInMemory ){
+      nStmtSpill = -1;
+    }
+    rc = sqlite3JournalOpen(pPager->pVfs, 0, pPager->sjfd, flags, nStmtSpill);
+  }
+  return rc;
+}
+
+/*
+** Append a record of the current state of page pPg to the sub-journal.
+**
+** If successful, set the bit corresponding to pPg->pgno in the bitvecs
+** for all open savepoints before returning.
+**
+** This function returns SQLITE_OK if everything is successful, an IO
+** error code if the attempt to write to the sub-journal fails, or
+** SQLITE_NOMEM if a malloc fails while setting a bit in a savepoint
+** bitvec.
+*/
+static int subjournalPage(PgHdr *pPg){
+  int rc = SQLITE_OK;
+  Pager *pPager = pPg->pPager;
+  if( pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
+
+    /* Open the sub-journal, if it has not already been opened */
+    assert( pPager->useJournal );
+    assert( isOpen(pPager->jfd) || pagerUseWal(pPager) );
+    assert( isOpen(pPager->sjfd) || pPager->nSubRec==0 );
+    assert( pagerUseWal(pPager)
+         || pageInJournal(pPager, pPg)
+         || pPg->pgno>pPager->dbOrigSize
+    );
+    rc = openSubJournal(pPager);
+
+    /* If the sub-journal was opened successfully (or was already open),
+    ** write the journal record into the file.  */
+    if( rc==SQLITE_OK ){
+      void *pData = pPg->pData;
+      i64 offset = (i64)pPager->nSubRec*(4+pPager->pageSize);
+      char *pData2;
+      pData2 = pData;
+      PAGERTRACE(("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno));
+      rc = write32bits(pPager->sjfd, offset, pPg->pgno);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
+      }
+    }
+  }
+  if( rc==SQLITE_OK ){
+    pPager->nSubRec++;
+    assert( pPager->nSavepoint>0 );
+    rc = addToSavepointBitvecs(pPager, pPg->pgno);
+  }
+  return rc;
+}
+static int subjournalPageIfRequired(PgHdr *pPg){
+  if( subjRequiresPage(pPg) ){
+    return subjournalPage(pPg);
+  }else{
+    return SQLITE_OK;
+  }
+}
+
+/*
+** This function is called by the pcache layer when it has reached some
+** soft memory limit. The first argument is a pointer to a Pager object
+** (cast as a void*). The pager is always 'purgeable' (not an in-memory
+** database). The second argument is a reference to a page that is
+** currently dirty but has no outstanding references. The page
+** is always associated with the Pager object passed as the first
+** argument.
+**
+** The job of this function is to make pPg clean by writing its contents
+** out to the database file, if possible. This may involve syncing the
+** journal file.
+**
+** If successful, sqlite3PcacheMakeClean() is called on the page and
+** SQLITE_OK returned. If an IO error occurs while trying to make the
+** page clean, the IO error code is returned. If the page cannot be
+** made clean for some other reason, but no error occurs, then SQLITE_OK
+** is returned by sqlite3PcacheMakeClean() is not called.
+*/
+static int pagerStress(void *p, PgHdr *pPg){
+  Pager *pPager = (Pager *)p;
+  int rc = SQLITE_OK;
+
+  assert( pPg->pPager==pPager );
+  assert( pPg->flags&PGHDR_DIRTY );
+
+  /* The doNotSpill NOSYNC bit is set during times when doing a sync of
+  ** journal (and adding a new header) is not allowed.  This occurs
+  ** during calls to sqlite3PagerWrite() while trying to journal multiple
+  ** pages belonging to the same sector.
+  **
+  ** The doNotSpill ROLLBACK and OFF bits inhibits all cache spilling
+  ** regardless of whether or not a sync is required.  This is set during
+  ** a rollback or by user request, respectively.
+  **
+  ** Spilling is also prohibited when in an error state since that could
+  ** lead to database corruption.   In the current implementation it
+  ** is impossible for sqlite3PcacheFetch() to be called with createFlag==3
+  ** while in the error state, hence it is impossible for this routine to
+  ** be called in the error state.  Nevertheless, we include a NEVER()
+  ** test for the error state as a safeguard against future changes.
+  */
+  if( NEVER(pPager->errCode) ) return SQLITE_OK;
+  testcase( pPager->doNotSpill & SPILLFLAG_ROLLBACK );
+  testcase( pPager->doNotSpill & SPILLFLAG_OFF );
+  testcase( pPager->doNotSpill & SPILLFLAG_NOSYNC );
+  if( pPager->doNotSpill
+   && ((pPager->doNotSpill & (SPILLFLAG_ROLLBACK|SPILLFLAG_OFF))!=0
+      || (pPg->flags & PGHDR_NEED_SYNC)!=0)
+  ){
+    return SQLITE_OK;
+  }
+
+  pPager->aStat[PAGER_STAT_SPILL]++;
+  pPg->pDirty = 0;
+  if( pagerUseWal(pPager) ){
+    /* Write a single frame for this page to the log. */
+    rc = subjournalPageIfRequired(pPg);
+    if( rc==SQLITE_OK ){
+      rc = pagerWalFrames(pPager, pPg, 0, 0);
+    }
+  }else{
+
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+    if( pPager->tempFile==0 ){
+      rc = sqlite3JournalCreate(pPager->jfd);
+      if( rc!=SQLITE_OK ) return pager_error(pPager, rc);
+    }
+#endif
+
+    /* Sync the journal file if required. */
+    if( pPg->flags&PGHDR_NEED_SYNC
+     || pPager->eState==PAGER_WRITER_CACHEMOD
+    ){
+      rc = syncJournal(pPager, 1);
+    }
+
+    /* Write the contents of the page out to the database file. */
+    if( rc==SQLITE_OK ){
+      assert( (pPg->flags&PGHDR_NEED_SYNC)==0 );
+      rc = pager_write_pagelist(pPager, pPg);
+    }
+  }
+
+  /* Mark the page as clean. */
+  if( rc==SQLITE_OK ){
+    PAGERTRACE(("STRESS %d page %d\n", PAGERID(pPager), pPg->pgno));
+    sqlite3PcacheMakeClean(pPg);
+  }
+
+  return pager_error(pPager, rc);
+}
+
+/*
+** Flush all unreferenced dirty pages to disk.
+*/
+SQLITE_PRIVATE int sqlite3PagerFlush(Pager *pPager){
+  int rc = pPager->errCode;
+  if( !MEMDB ){
+    PgHdr *pList = sqlite3PcacheDirtyList(pPager->pPCache);
+    assert( assert_pager_state(pPager) );
+    while( rc==SQLITE_OK && pList ){
+      PgHdr *pNext = pList->pDirty;
+      if( pList->nRef==0 ){
+        rc = pagerStress((void*)pPager, pList);
+      }
+      pList = pNext;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Allocate and initialize a new Pager object and put a pointer to it
+** in *ppPager. The pager should eventually be freed by passing it
+** to sqlite3PagerClose().
+**
+** The zFilename argument is the path to the database file to open.
+** If zFilename is NULL then a randomly-named temporary file is created
+** and used as the file to be cached. Temporary files are be deleted
+** automatically when they are closed. If zFilename is ":memory:" then
+** all information is held in cache. It is never written to disk.
+** This can be used to implement an in-memory database.
+**
+** The nExtra parameter specifies the number of bytes of space allocated
+** along with each page reference. This space is available to the user
+** via the sqlite3PagerGetExtra() API.  When a new page is allocated, the
+** first 8 bytes of this space are zeroed but the remainder is uninitialized.
+** (The extra space is used by btree as the MemPage object.)
+**
+** The flags argument is used to specify properties that affect the
+** operation of the pager. It should be passed some bitwise combination
+** of the PAGER_* flags.
+**
+** The vfsFlags parameter is a bitmask to pass to the flags parameter
+** of the xOpen() method of the supplied VFS when opening files.
+**
+** If the pager object is allocated and the specified file opened
+** successfully, SQLITE_OK is returned and *ppPager set to point to
+** the new pager object. If an error occurs, *ppPager is set to NULL
+** and error code returned. This function may return SQLITE_NOMEM
+** (sqlite3Malloc() is used to allocate memory), SQLITE_CANTOPEN or
+** various SQLITE_IO_XXX errors.
+*/
+SQLITE_PRIVATE int sqlite3PagerOpen(
+  sqlite3_vfs *pVfs,       /* The virtual file system to use */
+  Pager **ppPager,         /* OUT: Return the Pager structure here */
+  const char *zFilename,   /* Name of the database file to open */
+  int nExtra,              /* Extra bytes append to each in-memory page */
+  int flags,               /* flags controlling this file */
+  int vfsFlags,            /* flags passed through to sqlite3_vfs.xOpen() */
+  void (*xReinit)(DbPage*) /* Function to reinitialize pages */
+){
+  u8 *pPtr;
+  Pager *pPager = 0;       /* Pager object to allocate and return */
+  int rc = SQLITE_OK;      /* Return code */
+  int tempFile = 0;        /* True for temp files (incl. in-memory files) */
+  int memDb = 0;           /* True if this is an in-memory file */
+  int memJM = 0;           /* Memory journal mode */
+  int readOnly = 0;        /* True if this is a read-only file */
+  int journalFileSize;     /* Bytes to allocate for each journal fd */
+  char *zPathname = 0;     /* Full path to database file */
+  int nPathname = 0;       /* Number of bytes in zPathname */
+  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0; /* False to omit journal */
+  int pcacheSize = sqlite3PcacheSize();       /* Bytes to allocate for PCache */
+  u32 szPageDflt = SQLITE_DEFAULT_PAGE_SIZE;  /* Default page size */
+  const char *zUri = 0;    /* URI args to copy */
+  int nUriByte = 1;        /* Number of bytes of URI args at *zUri */
+
+  /* Figure out how much space is required for each journal file-handle
+  ** (there are two of them, the main journal and the sub-journal).  */
+  journalFileSize = ROUND8(sqlite3JournalSize(pVfs));
+
+  /* Set the output variable to NULL in case an error occurs. */
+  *ppPager = 0;
+
+#ifndef SQLITE_OMIT_MEMORYDB
+  if( flags & PAGER_MEMORY ){
+    memDb = 1;
+    if( zFilename && zFilename[0] ){
+      zPathname = sqlite3DbStrDup(0, zFilename);
+      if( zPathname==0  ) return SQLITE_NOMEM_BKPT;
+      nPathname = sqlite3Strlen30(zPathname);
+      zFilename = 0;
+    }
+  }
+#endif
+
+  /* Compute and store the full pathname in an allocated buffer pointed
+  ** to by zPathname, length nPathname. Or, if this is a temporary file,
+  ** leave both nPathname and zPathname set to 0.
+  */
+  if( zFilename && zFilename[0] ){
+    const char *z;
+    nPathname = pVfs->mxPathname+1;
+    zPathname = sqlite3DbMallocRaw(0, nPathname*2);
+    if( zPathname==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    zPathname[0] = 0; /* Make sure initialized even if FullPathname() fails */
+    rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_OK_SYMLINK ){
+        if( vfsFlags & SQLITE_OPEN_NOFOLLOW ){
+          rc = SQLITE_CANTOPEN_SYMLINK;
+        }else{
+          rc = SQLITE_OK;
+        }
+      }
+    }
+    nPathname = sqlite3Strlen30(zPathname);
+    z = zUri = &zFilename[sqlite3Strlen30(zFilename)+1];
+    while( *z ){
+      z += strlen(z)+1;
+      z += strlen(z)+1;
+    }
+    nUriByte = (int)(&z[1] - zUri);
+    assert( nUriByte>=1 );
+    if( rc==SQLITE_OK && nPathname+8>pVfs->mxPathname ){
+      /* This branch is taken when the journal path required by
+      ** the database being opened will be more than pVfs->mxPathname
+      ** bytes in length. This means the database cannot be opened,
+      ** as it will not be possible to open the journal file or even
+      ** check for a hot-journal before reading.
+      */
+      rc = SQLITE_CANTOPEN_BKPT;
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3DbFree(0, zPathname);
+      return rc;
+    }
+  }
+
+  /* Allocate memory for the Pager structure, PCache object, the
+  ** three file descriptors, the database file name and the journal
+  ** file name. The layout in memory is as follows:
+  **
+  **     Pager object                    (sizeof(Pager) bytes)
+  **     PCache object                   (sqlite3PcacheSize() bytes)
+  **     Database file handle            (pVfs->szOsFile bytes)
+  **     Sub-journal file handle         (journalFileSize bytes)
+  **     Main journal file handle        (journalFileSize bytes)
+  **     Ptr back to the Pager           (sizeof(Pager*) bytes)
+  **     \0\0\0\0 database prefix        (4 bytes)
+  **     Database file name              (nPathname+1 bytes)
+  **     URI query parameters            (nUriByte bytes)
+  **     Journal filename                (nPathname+8+1 bytes)
+  **     WAL filename                    (nPathname+4+1 bytes)
+  **     \0\0\0 terminator               (3 bytes)
+  **
+  ** Some 3rd-party software, over which we have no control, depends on
+  ** the specific order of the filenames and the \0 separators between them
+  ** so that it can (for example) find the database filename given the WAL
+  ** filename without using the sqlite3_filename_database() API.  This is a
+  ** misuse of SQLite and a bug in the 3rd-party software, but the 3rd-party
+  ** software is in widespread use, so we try to avoid changing the filename
+  ** order and formatting if possible.  In particular, the details of the
+  ** filename format expected by 3rd-party software should be as follows:
+  **
+  **   - Main Database Path
+  **   - \0
+  **   - Multiple URI components consisting of:
+  **     - Key
+  **     - \0
+  **     - Value
+  **     - \0
+  **   - \0
+  **   - Journal Path
+  **   - \0
+  **   - WAL Path (zWALName)
+  **   - \0
+  **
+  ** The sqlite3_create_filename() interface and the databaseFilename() utility
+  ** that is used by sqlite3_filename_database() and kin also depend on the
+  ** specific formatting and order of the various filenames, so if the format
+  ** changes here, be sure to change it there as well.
+  */
+  assert( SQLITE_PTRSIZE==sizeof(Pager*) );
+  pPtr = (u8 *)sqlite3MallocZero(
+    ROUND8(sizeof(*pPager)) +            /* Pager structure */
+    ROUND8(pcacheSize) +                 /* PCache object */
+    ROUND8(pVfs->szOsFile) +             /* The main db file */
+    journalFileSize * 2 +                /* The two journal files */
+    SQLITE_PTRSIZE +                     /* Space to hold a pointer */
+    4 +                                  /* Database prefix */
+    nPathname + 1 +                      /* database filename */
+    nUriByte +                           /* query parameters */
+    nPathname + 8 + 1 +                  /* Journal filename */
+#ifndef SQLITE_OMIT_WAL
+    nPathname + 4 + 1 +                  /* WAL filename */
+#endif
+    3                                    /* Terminator */
+  );
+  assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
+  if( !pPtr ){
+    sqlite3DbFree(0, zPathname);
+    return SQLITE_NOMEM_BKPT;
+  }
+  pPager = (Pager*)pPtr;                  pPtr += ROUND8(sizeof(*pPager));
+  pPager->pPCache = (PCache*)pPtr;        pPtr += ROUND8(pcacheSize);
+  pPager->fd = (sqlite3_file*)pPtr;       pPtr += ROUND8(pVfs->szOsFile);
+  pPager->sjfd = (sqlite3_file*)pPtr;     pPtr += journalFileSize;
+  pPager->jfd =  (sqlite3_file*)pPtr;     pPtr += journalFileSize;
+  assert( EIGHT_BYTE_ALIGNMENT(pPager->jfd) );
+  memcpy(pPtr, &pPager, SQLITE_PTRSIZE);  pPtr += SQLITE_PTRSIZE;
+
+  /* Fill in the Pager.zFilename and pPager.zQueryParam fields */
+                                          pPtr += 4;  /* Skip zero prefix */
+  pPager->zFilename = (char*)pPtr;
+  if( nPathname>0 ){
+    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname + 1;
+    if( zUri ){
+      memcpy(pPtr, zUri, nUriByte);       pPtr += nUriByte;
+    }else{
+                                          pPtr++;
+    }
+  }
+
+
+  /* Fill in Pager.zJournal */
+  if( nPathname>0 ){
+    pPager->zJournal = (char*)pPtr;
+    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname;
+    memcpy(pPtr, "-journal",8);           pPtr += 8 + 1;
+#ifdef SQLITE_ENABLE_8_3_NAMES
+    sqlite3FileSuffix3(zFilename,pPager->zJournal);
+    pPtr = (u8*)(pPager->zJournal + sqlite3Strlen30(pPager->zJournal)+1);
+#endif
+  }else{
+    pPager->zJournal = 0;
+  }
+
+#ifndef SQLITE_OMIT_WAL
+  /* Fill in Pager.zWal */
+  if( nPathname>0 ){
+    pPager->zWal = (char*)pPtr;
+    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname;
+    memcpy(pPtr, "-wal", 4);              pPtr += 4 + 1;
+#ifdef SQLITE_ENABLE_8_3_NAMES
+    sqlite3FileSuffix3(zFilename, pPager->zWal);
+    pPtr = (u8*)(pPager->zWal + sqlite3Strlen30(pPager->zWal)+1);
+#endif
+  }else{
+    pPager->zWal = 0;
+  }
+#endif
+  (void)pPtr;  /* Suppress warning about unused pPtr value */
+
+  if( nPathname ) sqlite3DbFree(0, zPathname);
+  pPager->pVfs = pVfs;
+  pPager->vfsFlags = vfsFlags;
+
+  /* Open the pager file.
+  */
+  if( zFilename && zFilename[0] ){
+    int fout = 0;                    /* VFS flags returned by xOpen() */
+    rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd, vfsFlags, &fout);
+    assert( !memDb );
+    pPager->memVfs = memJM = (fout&SQLITE_OPEN_MEMORY)!=0;
+    readOnly = (fout&SQLITE_OPEN_READONLY)!=0;
+
+    /* If the file was successfully opened for read/write access,
+    ** choose a default page size in case we have to create the
+    ** database file. The default page size is the maximum of:
+    **
+    **    + SQLITE_DEFAULT_PAGE_SIZE,
+    **    + The value returned by sqlite3OsSectorSize()
+    **    + The largest page size that can be written atomically.
+    */
+    if( rc==SQLITE_OK ){
+      int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
+      if( !readOnly ){
+        setSectorSize(pPager);
+        assert(SQLITE_DEFAULT_PAGE_SIZE<=SQLITE_MAX_DEFAULT_PAGE_SIZE);
+        if( szPageDflt<pPager->sectorSize ){
+          if( pPager->sectorSize>SQLITE_MAX_DEFAULT_PAGE_SIZE ){
+            szPageDflt = SQLITE_MAX_DEFAULT_PAGE_SIZE;
+          }else{
+            szPageDflt = (u32)pPager->sectorSize;
+          }
+        }
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+        {
+          int ii;
+          assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
+          assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));
+          assert(SQLITE_MAX_DEFAULT_PAGE_SIZE<=65536);
+          for(ii=szPageDflt; ii<=SQLITE_MAX_DEFAULT_PAGE_SIZE; ii=ii*2){
+            if( iDc&(SQLITE_IOCAP_ATOMIC|(ii>>8)) ){
+              szPageDflt = ii;
+            }
+          }
+        }
+#endif
+      }
+      pPager->noLock = sqlite3_uri_boolean(pPager->zFilename, "nolock", 0);
+      if( (iDc & SQLITE_IOCAP_IMMUTABLE)!=0
+       || sqlite3_uri_boolean(pPager->zFilename, "immutable", 0) ){
+          vfsFlags |= SQLITE_OPEN_READONLY;
+          goto act_like_temp_file;
+      }
+    }
+  }else{
+    /* If a temporary file is requested, it is not opened immediately.
+    ** In this case we accept the default page size and delay actually
+    ** opening the file until the first call to OsWrite().
+    **
+    ** This branch is also run for an in-memory database. An in-memory
+    ** database is the same as a temp-file that is never written out to
+    ** disk and uses an in-memory rollback journal.
+    **
+    ** This branch also runs for files marked as immutable.
+    */
+act_like_temp_file:
+    tempFile = 1;
+    pPager->eState = PAGER_READER;     /* Pretend we already have a lock */
+    pPager->eLock = EXCLUSIVE_LOCK;    /* Pretend we are in EXCLUSIVE mode */
+    pPager->noLock = 1;                /* Do no locking */
+    readOnly = (vfsFlags&SQLITE_OPEN_READONLY);
+  }
+
+  /* The following call to PagerSetPagesize() serves to set the value of
+  ** Pager.pageSize and to allocate the Pager.pTmpSpace buffer.
+  */
+  if( rc==SQLITE_OK ){
+    assert( pPager->memDb==0 );
+    rc = sqlite3PagerSetPagesize(pPager, &szPageDflt, -1);
+    testcase( rc!=SQLITE_OK );
+  }
+
+  /* Initialize the PCache object. */
+  if( rc==SQLITE_OK ){
+    nExtra = ROUND8(nExtra);
+    assert( nExtra>=8 && nExtra<1000 );
+    rc = sqlite3PcacheOpen(szPageDflt, nExtra, !memDb,
+                       !memDb?pagerStress:0, (void *)pPager, pPager->pPCache);
+  }
+
+  /* If an error occurred above, free the  Pager structure and close the file.
+  */
+  if( rc!=SQLITE_OK ){
+    sqlite3OsClose(pPager->fd);
+    sqlite3PageFree(pPager->pTmpSpace);
+    sqlite3_free(pPager);
+    return rc;
+  }
+
+  PAGERTRACE(("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename));
+  IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename))
+
+  pPager->useJournal = (u8)useJournal;
+  /* pPager->stmtOpen = 0; */
+  /* pPager->stmtInUse = 0; */
+  /* pPager->nRef = 0; */
+  /* pPager->stmtSize = 0; */
+  /* pPager->stmtJSize = 0; */
+  /* pPager->nPage = 0; */
+  pPager->mxPgno = SQLITE_MAX_PAGE_COUNT;
+  /* pPager->state = PAGER_UNLOCK; */
+  /* pPager->errMask = 0; */
+  pPager->tempFile = (u8)tempFile;
+  assert( tempFile==PAGER_LOCKINGMODE_NORMAL
+          || tempFile==PAGER_LOCKINGMODE_EXCLUSIVE );
+  assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
+  pPager->exclusiveMode = (u8)tempFile;
+  pPager->changeCountDone = pPager->tempFile;
+  pPager->memDb = (u8)memDb;
+  pPager->readOnly = (u8)readOnly;
+  assert( useJournal || pPager->tempFile );
+  sqlite3PagerSetFlags(pPager, (SQLITE_DEFAULT_SYNCHRONOUS+1)|PAGER_CACHESPILL);
+  /* pPager->pFirst = 0; */
+  /* pPager->pFirstSynced = 0; */
+  /* pPager->pLast = 0; */
+  pPager->nExtra = (u16)nExtra;
+  pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
+  assert( isOpen(pPager->fd) || tempFile );
+  setSectorSize(pPager);
+  if( !useJournal ){
+    pPager->journalMode = PAGER_JOURNALMODE_OFF;
+  }else if( memDb || memJM ){
+    pPager->journalMode = PAGER_JOURNALMODE_MEMORY;
+  }
+  /* pPager->xBusyHandler = 0; */
+  /* pPager->pBusyHandlerArg = 0; */
+  pPager->xReiniter = xReinit;
+  setGetterMethod(pPager);
+  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
+  /* pPager->szMmap = SQLITE_DEFAULT_MMAP_SIZE // will be set by btree.c */
+
+  *ppPager = pPager;
+  return SQLITE_OK;
+}
+
+/*
+** Return the sqlite3_file for the main database given the name
+** of the corresponding WAL or Journal name as passed into
+** xOpen.
+*/
+SQLITE_API sqlite3_file *sqlite3_database_file_object(const char *zName){
+  Pager *pPager;
+  const char *p;
+  while( zName[-1]!=0 || zName[-2]!=0 || zName[-3]!=0 || zName[-4]!=0 ){
+    zName--;
+  }
+  p = zName - 4 - sizeof(Pager*);
+  assert( EIGHT_BYTE_ALIGNMENT(p) );
+  pPager = *(Pager**)p;
+  return pPager->fd;
+}
+
+
+/*
+** This function is called after transitioning from PAGER_UNLOCK to
+** PAGER_SHARED state. It tests if there is a hot journal present in
+** the file-system for the given pager. A hot journal is one that
+** needs to be played back. According to this function, a hot-journal
+** file exists if the following criteria are met:
+**
+**   * The journal file exists in the file system, and
+**   * No process holds a RESERVED or greater lock on the database file, and
+**   * The database file itself is greater than 0 bytes in size, and
+**   * The first byte of the journal file exists and is not 0x00.
+**
+** If the current size of the database file is 0 but a journal file
+** exists, that is probably an old journal left over from a prior
+** database with the same name. In this case the journal file is
+** just deleted using OsDelete, *pExists is set to 0 and SQLITE_OK
+** is returned.
+**
+** This routine does not check if there is a super-journal filename
+** at the end of the file. If there is, and that super-journal file
+** does not exist, then the journal file is not really hot. In this
+** case this routine will return a false-positive. The pager_playback()
+** routine will discover that the journal file is not really hot and
+** will not roll it back.
+**
+** If a hot-journal file is found to exist, *pExists is set to 1 and
+** SQLITE_OK returned. If no hot-journal file is present, *pExists is
+** set to 0 and SQLITE_OK returned. If an IO error occurs while trying
+** to determine whether or not a hot-journal file exists, the IO error
+** code is returned and the value of *pExists is undefined.
+*/
+static int hasHotJournal(Pager *pPager, int *pExists){
+  sqlite3_vfs * const pVfs = pPager->pVfs;
+  int rc = SQLITE_OK;           /* Return code */
+  int exists = 1;               /* True if a journal file is present */
+  int jrnlOpen = !!isOpen(pPager->jfd);
+
+  assert( pPager->useJournal );
+  assert( isOpen(pPager->fd) );
+  assert( pPager->eState==PAGER_OPEN );
+
+  assert( jrnlOpen==0 || ( sqlite3OsDeviceCharacteristics(pPager->jfd) &
+    SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
+  ));
+
+  *pExists = 0;
+  if( !jrnlOpen ){
+    rc = sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &exists);
+  }
+  if( rc==SQLITE_OK && exists ){
+    int locked = 0;             /* True if some process holds a RESERVED lock */
+
+    /* Race condition here:  Another process might have been holding the
+    ** the RESERVED lock and have a journal open at the sqlite3OsAccess()
+    ** call above, but then delete the journal and drop the lock before
+    ** we get to the following sqlite3OsCheckReservedLock() call.  If that
+    ** is the case, this routine might think there is a hot journal when
+    ** in fact there is none.  This results in a false-positive which will
+    ** be dealt with by the playback routine.  Ticket #3883.
+    */
+    rc = sqlite3OsCheckReservedLock(pPager->fd, &locked);
+    if( rc==SQLITE_OK && !locked ){
+      Pgno nPage;                 /* Number of pages in database file */
+
+      assert( pPager->tempFile==0 );
+      rc = pagerPagecount(pPager, &nPage);
+      if( rc==SQLITE_OK ){
+        /* If the database is zero pages in size, that means that either (1) the
+        ** journal is a remnant from a prior database with the same name where
+        ** the database file but not the journal was deleted, or (2) the initial
+        ** transaction that populates a new database is being rolled back.
+        ** In either case, the journal file can be deleted.  However, take care
+        ** not to delete the journal file if it is already open due to
+        ** journal_mode=PERSIST.
+        */
+        if( nPage==0 && !jrnlOpen ){
+          sqlite3BeginBenignMalloc();
+          if( pagerLockDb(pPager, RESERVED_LOCK)==SQLITE_OK ){
+            sqlite3OsDelete(pVfs, pPager->zJournal, 0);
+            if( !pPager->exclusiveMode ) pagerUnlockDb(pPager, SHARED_LOCK);
+          }
+          sqlite3EndBenignMalloc();
+        }else{
+          /* The journal file exists and no other connection has a reserved
+          ** or greater lock on the database file. Now check that there is
+          ** at least one non-zero bytes at the start of the journal file.
+          ** If there is, then we consider this journal to be hot. If not,
+          ** it can be ignored.
+          */
+          if( !jrnlOpen ){
+            int f = SQLITE_OPEN_READONLY|SQLITE_OPEN_MAIN_JOURNAL;
+            rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &f);
+          }
+          if( rc==SQLITE_OK ){
+            u8 first = 0;
+            rc = sqlite3OsRead(pPager->jfd, (void *)&first, 1, 0);
+            if( rc==SQLITE_IOERR_SHORT_READ ){
+              rc = SQLITE_OK;
+            }
+            if( !jrnlOpen ){
+              sqlite3OsClose(pPager->jfd);
+            }
+            *pExists = (first!=0);
+          }else if( rc==SQLITE_CANTOPEN ){
+            /* If we cannot open the rollback journal file in order to see if
+            ** it has a zero header, that might be due to an I/O error, or
+            ** it might be due to the race condition described above and in
+            ** ticket #3883.  Either way, assume that the journal is hot.
+            ** This might be a false positive.  But if it is, then the
+            ** automatic journal playback and recovery mechanism will deal
+            ** with it under an EXCLUSIVE lock where we do not need to
+            ** worry so much with race conditions.
+            */
+            *pExists = 1;
+            rc = SQLITE_OK;
+          }
+        }
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is called to obtain a shared lock on the database file.
+** It is illegal to call sqlite3PagerGet() until after this function
+** has been successfully called. If a shared-lock is already held when
+** this function is called, it is a no-op.
+**
+** The following operations are also performed by this function.
+**
+**   1) If the pager is currently in PAGER_OPEN state (no lock held
+**      on the database file), then an attempt is made to obtain a
+**      SHARED lock on the database file. Immediately after obtaining
+**      the SHARED lock, the file-system is checked for a hot-journal,
+**      which is played back if present. Following any hot-journal
+**      rollback, the contents of the cache are validated by checking
+**      the 'change-counter' field of the database file header and
+**      discarded if they are found to be invalid.
+**
+**   2) If the pager is running in exclusive-mode, and there are currently
+**      no outstanding references to any pages, and is in the error state,
+**      then an attempt is made to clear the error state by discarding
+**      the contents of the page cache and rolling back any open journal
+**      file.
+**
+** If everything is successful, SQLITE_OK is returned. If an IO error
+** occurs while locking the database, checking for a hot-journal file or
+** rolling back a journal file, the IO error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerSharedLock(Pager *pPager){
+  int rc = SQLITE_OK;                /* Return code */
+
+  /* This routine is only called from b-tree and only when there are no
+  ** outstanding pages. This implies that the pager state should either
+  ** be OPEN or READER. READER is only possible if the pager is or was in
+  ** exclusive access mode.  */
+  assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->eState==PAGER_OPEN || pPager->eState==PAGER_READER );
+  assert( pPager->errCode==SQLITE_OK );
+
+  if( !pagerUseWal(pPager) && pPager->eState==PAGER_OPEN ){
+    int bHotJournal = 1;          /* True if there exists a hot journal-file */
+
+    assert( !MEMDB );
+    assert( pPager->tempFile==0 || pPager->eLock==EXCLUSIVE_LOCK );
+
+    rc = pager_wait_on_lock(pPager, SHARED_LOCK);
+    if( rc!=SQLITE_OK ){
+      assert( pPager->eLock==NO_LOCK || pPager->eLock==UNKNOWN_LOCK );
+      goto failed;
+    }
+
+    /* If a journal file exists, and there is no RESERVED lock on the
+    ** database file, then it either needs to be played back or deleted.
+    */
+    if( pPager->eLock<=SHARED_LOCK ){
+      rc = hasHotJournal(pPager, &bHotJournal);
+    }
+    if( rc!=SQLITE_OK ){
+      goto failed;
+    }
+    if( bHotJournal ){
+      if( pPager->readOnly ){
+        rc = SQLITE_READONLY_ROLLBACK;
+        goto failed;
+      }
+
+      /* Get an EXCLUSIVE lock on the database file. At this point it is
+      ** important that a RESERVED lock is not obtained on the way to the
+      ** EXCLUSIVE lock. If it were, another process might open the
+      ** database file, detect the RESERVED lock, and conclude that the
+      ** database is safe to read while this process is still rolling the
+      ** hot-journal back.
+      **
+      ** Because the intermediate RESERVED lock is not requested, any
+      ** other process attempting to access the database file will get to
+      ** this point in the code and fail to obtain its own EXCLUSIVE lock
+      ** on the database file.
+      **
+      ** Unless the pager is in locking_mode=exclusive mode, the lock is
+      ** downgraded to SHARED_LOCK before this function returns.
+      */
+      rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
+      if( rc!=SQLITE_OK ){
+        goto failed;
+      }
+
+      /* If it is not already open and the file exists on disk, open the
+      ** journal for read/write access. Write access is required because
+      ** in exclusive-access mode the file descriptor will be kept open
+      ** and possibly used for a transaction later on. Also, write-access
+      ** is usually required to finalize the journal in journal_mode=persist
+      ** mode (and also for journal_mode=truncate on some systems).
+      **
+      ** If the journal does not exist, it usually means that some
+      ** other connection managed to get in and roll it back before
+      ** this connection obtained the exclusive lock above. Or, it
+      ** may mean that the pager was in the error-state when this
+      ** function was called and the journal file does not exist.
+      */
+      if( !isOpen(pPager->jfd) && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
+        sqlite3_vfs * const pVfs = pPager->pVfs;
+        int bExists;              /* True if journal file exists */
+        rc = sqlite3OsAccess(
+            pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &bExists);
+        if( rc==SQLITE_OK && bExists ){
+          int fout = 0;
+          int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
+          assert( !pPager->tempFile );
+          rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
+          assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
+          if( rc==SQLITE_OK && fout&SQLITE_OPEN_READONLY ){
+            rc = SQLITE_CANTOPEN_BKPT;
+            sqlite3OsClose(pPager->jfd);
+          }
+        }
+      }
+
+      /* Playback and delete the journal.  Drop the database write
+      ** lock and reacquire the read lock. Purge the cache before
+      ** playing back the hot-journal so that we don't end up with
+      ** an inconsistent cache.  Sync the hot journal before playing
+      ** it back since the process that crashed and left the hot journal
+      ** probably did not sync it and we are required to always sync
+      ** the journal before playing it back.
+      */
+      if( isOpen(pPager->jfd) ){
+        assert( rc==SQLITE_OK );
+        rc = pagerSyncHotJournal(pPager);
+        if( rc==SQLITE_OK ){
+          rc = pager_playback(pPager, !pPager->tempFile);
+          pPager->eState = PAGER_OPEN;
+        }
+      }else if( !pPager->exclusiveMode ){
+        pagerUnlockDb(pPager, SHARED_LOCK);
+      }
+
+      if( rc!=SQLITE_OK ){
+        /* This branch is taken if an error occurs while trying to open
+        ** or roll back a hot-journal while holding an EXCLUSIVE lock. The
+        ** pager_unlock() routine will be called before returning to unlock
+        ** the file. If the unlock attempt fails, then Pager.eLock must be
+        ** set to UNKNOWN_LOCK (see the comment above the #define for
+        ** UNKNOWN_LOCK above for an explanation).
+        **
+        ** In order to get pager_unlock() to do this, set Pager.eState to
+        ** PAGER_ERROR now. This is not actually counted as a transition
+        ** to ERROR state in the state diagram at the top of this file,
+        ** since we know that the same call to pager_unlock() will very
+        ** shortly transition the pager object to the OPEN state. Calling
+        ** assert_pager_state() would fail now, as it should not be possible
+        ** to be in ERROR state when there are zero outstanding page
+        ** references.
+        */
+        pager_error(pPager, rc);
+        goto failed;
+      }
+
+      assert( pPager->eState==PAGER_OPEN );
+      assert( (pPager->eLock==SHARED_LOCK)
+           || (pPager->exclusiveMode && pPager->eLock>SHARED_LOCK)
+      );
+    }
+
+    if( !pPager->tempFile && pPager->hasHeldSharedLock ){
+      /* The shared-lock has just been acquired then check to
+      ** see if the database has been modified.  If the database has changed,
+      ** flush the cache.  The hasHeldSharedLock flag prevents this from
+      ** occurring on the very first access to a file, in order to save a
+      ** single unnecessary sqlite3OsRead() call at the start-up.
+      **
+      ** Database changes are detected by looking at 15 bytes beginning
+      ** at offset 24 into the file.  The first 4 of these 16 bytes are
+      ** a 32-bit counter that is incremented with each change.  The
+      ** other bytes change randomly with each file change when
+      ** a codec is in use.
+      **
+      ** There is a vanishingly small chance that a change will not be
+      ** detected.  The chance of an undetected change is so small that
+      ** it can be neglected.
+      */
+      char dbFileVers[sizeof(pPager->dbFileVers)];
+
+      IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
+      rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
+      if( rc!=SQLITE_OK ){
+        if( rc!=SQLITE_IOERR_SHORT_READ ){
+          goto failed;
+        }
+        memset(dbFileVers, 0, sizeof(dbFileVers));
+      }
+
+      if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
+        pager_reset(pPager);
+
+        /* Unmap the database file. It is possible that external processes
+        ** may have truncated the database file and then extended it back
+        ** to its original size while this process was not holding a lock.
+        ** In this case there may exist a Pager.pMap mapping that appears
+        ** to be the right size but is not actually valid. Avoid this
+        ** possibility by unmapping the db here. */
+        if( USEFETCH(pPager) ){
+          sqlite3OsUnfetch(pPager->fd, 0, 0);
+        }
+      }
+    }
+
+    /* If there is a WAL file in the file-system, open this database in WAL
+    ** mode. Otherwise, the following function call is a no-op.
+    */
+    rc = pagerOpenWalIfPresent(pPager);
+#ifndef SQLITE_OMIT_WAL
+    assert( pPager->pWal==0 || rc==SQLITE_OK );
+#endif
+  }
+
+  if( pagerUseWal(pPager) ){
+    assert( rc==SQLITE_OK );
+    rc = pagerBeginReadTransaction(pPager);
+  }
+
+  if( pPager->tempFile==0 && pPager->eState==PAGER_OPEN && rc==SQLITE_OK ){
+    rc = pagerPagecount(pPager, &pPager->dbSize);
+  }
+
+ failed:
+  if( rc!=SQLITE_OK ){
+    assert( !MEMDB );
+    pager_unlock(pPager);
+    assert( pPager->eState==PAGER_OPEN );
+  }else{
+    pPager->eState = PAGER_READER;
+    pPager->hasHeldSharedLock = 1;
+  }
+  return rc;
+}
+
+/*
+** If the reference count has reached zero, rollback any active
+** transaction and unlock the pager.
+**
+** Except, in locking_mode=EXCLUSIVE when there is nothing to in
+** the rollback journal, the unlock is not performed and there is
+** nothing to rollback, so this routine is a no-op.
+*/
+static void pagerUnlockIfUnused(Pager *pPager){
+  if( sqlite3PcacheRefCount(pPager->pPCache)==0 ){
+    assert( pPager->nMmapOut==0 ); /* because page1 is never memory mapped */
+    pagerUnlockAndRollback(pPager);
+  }
+}
+
+/*
+** The page getter methods each try to acquire a reference to a
+** page with page number pgno. If the requested reference is
+** successfully obtained, it is copied to *ppPage and SQLITE_OK returned.
+**
+** There are different implementations of the getter method depending
+** on the current state of the pager.
+**
+**     getPageNormal()         --  The normal getter
+**     getPageError()          --  Used if the pager is in an error state
+**     getPageMmap()           --  Used if memory-mapped I/O is enabled
+**
+** If the requested page is already in the cache, it is returned.
+** Otherwise, a new page object is allocated and populated with data
+** read from the database file. In some cases, the pcache module may
+** choose not to allocate a new page object and may reuse an existing
+** object with no outstanding references.
+**
+** The extra data appended to a page is always initialized to zeros the
+** first time a page is loaded into memory. If the page requested is
+** already in the cache when this function is called, then the extra
+** data is left as it was when the page object was last used.
+**
+** If the database image is smaller than the requested page or if
+** the flags parameter contains the PAGER_GET_NOCONTENT bit and the
+** requested page is not already stored in the cache, then no
+** actual disk read occurs. In this case the memory image of the
+** page is initialized to all zeros.
+**
+** If PAGER_GET_NOCONTENT is true, it means that we do not care about
+** the contents of the page. This occurs in two scenarios:
+**
+**   a) When reading a free-list leaf page from the database, and
+**
+**   b) When a savepoint is being rolled back and we need to load
+**      a new page into the cache to be filled with the data read
+**      from the savepoint journal.
+**
+** If PAGER_GET_NOCONTENT is true, then the data returned is zeroed instead
+** of being read from the database. Additionally, the bits corresponding
+** to pgno in Pager.pInJournal (bitvec of pages already written to the
+** journal file) and the PagerSavepoint.pInSavepoint bitvecs of any open
+** savepoints are set. This means if the page is made writable at any
+** point in the future, using a call to sqlite3PagerWrite(), its contents
+** will not be journaled. This saves IO.
+**
+** The acquisition might fail for several reasons.  In all cases,
+** an appropriate error code is returned and *ppPage is set to NULL.
+**
+** See also sqlite3PagerLookup().  Both this routine and Lookup() attempt
+** to find a page in the in-memory cache first.  If the page is not already
+** in memory, this routine goes to disk to read it in whereas Lookup()
+** just returns 0.  This routine acquires a read-lock the first time it
+** has to go to disk, and could also playback an old journal if necessary.
+** Since Lookup() never goes to disk, it never has to deal with locks
+** or journal files.
+*/
+static int getPageNormal(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int flags           /* PAGER_GET_XXX flags */
+){
+  int rc = SQLITE_OK;
+  PgHdr *pPg;
+  u8 noContent;                   /* True if PAGER_GET_NOCONTENT is set */
+  sqlite3_pcache_page *pBase;
+
+  assert( pPager->errCode==SQLITE_OK );
+  assert( pPager->eState>=PAGER_READER );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->hasHeldSharedLock==1 );
+
+  if( pgno==0 ) return SQLITE_CORRUPT_BKPT;
+  pBase = sqlite3PcacheFetch(pPager->pPCache, pgno, 3);
+  if( pBase==0 ){
+    pPg = 0;
+    rc = sqlite3PcacheFetchStress(pPager->pPCache, pgno, &pBase);
+    if( rc!=SQLITE_OK ) goto pager_acquire_err;
+    if( pBase==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto pager_acquire_err;
+    }
+  }
+  pPg = *ppPage = sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pBase);
+  assert( pPg==(*ppPage) );
+  assert( pPg->pgno==pgno );
+  assert( pPg->pPager==pPager || pPg->pPager==0 );
+
+  noContent = (flags & PAGER_GET_NOCONTENT)!=0;
+  if( pPg->pPager && !noContent ){
+    /* In this case the pcache already contains an initialized copy of
+    ** the page. Return without further ado.  */
+    assert( pgno!=PAGER_SJ_PGNO(pPager) );
+    pPager->aStat[PAGER_STAT_HIT]++;
+    return SQLITE_OK;
+
+  }else{
+    /* The pager cache has created a new page. Its content needs to
+    ** be initialized. But first some error checks:
+    **
+    ** (*) obsolete.  Was: maximum page number is 2^31
+    ** (2) Never try to fetch the locking page
+    */
+    if( pgno==PAGER_SJ_PGNO(pPager) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto pager_acquire_err;
+    }
+
+    pPg->pPager = pPager;
+
+    assert( !isOpen(pPager->fd) || !MEMDB );
+    if( !isOpen(pPager->fd) || pPager->dbSize<pgno || noContent ){
+      if( pgno>pPager->mxPgno ){
+        rc = SQLITE_FULL;
+        if( pgno<=pPager->dbSize ){
+          sqlite3PcacheRelease(pPg);
+          pPg = 0;
+        }
+        goto pager_acquire_err;
+      }
+      if( noContent ){
+        /* Failure to set the bits in the InJournal bit-vectors is benign.
+        ** It merely means that we might do some extra work to journal a
+        ** page that does not need to be journaled.  Nevertheless, be sure
+        ** to test the case where a malloc error occurs while trying to set
+        ** a bit in a bit vector.
+        */
+        sqlite3BeginBenignMalloc();
+        if( pgno<=pPager->dbOrigSize ){
+          TESTONLY( rc = ) sqlite3BitvecSet(pPager->pInJournal, pgno);
+          testcase( rc==SQLITE_NOMEM );
+        }
+        TESTONLY( rc = ) addToSavepointBitvecs(pPager, pgno);
+        testcase( rc==SQLITE_NOMEM );
+        sqlite3EndBenignMalloc();
+      }
+      memset(pPg->pData, 0, pPager->pageSize);
+      IOTRACE(("ZERO %p %d\n", pPager, pgno));
+    }else{
+      assert( pPg->pPager==pPager );
+      pPager->aStat[PAGER_STAT_MISS]++;
+      rc = readDbPage(pPg);
+      if( rc!=SQLITE_OK ){
+        goto pager_acquire_err;
+      }
+    }
+    pager_set_pagehash(pPg);
+  }
+  return SQLITE_OK;
+
+pager_acquire_err:
+  assert( rc!=SQLITE_OK );
+  if( pPg ){
+    sqlite3PcacheDrop(pPg);
+  }
+  pagerUnlockIfUnused(pPager);
+  *ppPage = 0;
+  return rc;
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/* The page getter for when memory-mapped I/O is enabled */
+static int getPageMMap(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int flags           /* PAGER_GET_XXX flags */
+){
+  int rc = SQLITE_OK;
+  PgHdr *pPg = 0;
+  u32 iFrame = 0;                 /* Frame to read from WAL file */
+
+  /* It is acceptable to use a read-only (mmap) page for any page except
+  ** page 1 if there is no write-transaction open or the ACQUIRE_READONLY
+  ** flag was specified by the caller. And so long as the db is not a
+  ** temporary or in-memory database.  */
+  const int bMmapOk = (pgno>1
+   && (pPager->eState==PAGER_READER || (flags & PAGER_GET_READONLY))
+  );
+
+  assert( USEFETCH(pPager) );
+
+  /* Optimization note:  Adding the "pgno<=1" term before "pgno==0" here
+  ** allows the compiler optimizer to reuse the results of the "pgno>1"
+  ** test in the previous statement, and avoid testing pgno==0 in the
+  ** common case where pgno is large. */
+  if( pgno<=1 && pgno==0 ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  assert( pPager->eState>=PAGER_READER );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->hasHeldSharedLock==1 );
+  assert( pPager->errCode==SQLITE_OK );
+
+  if( bMmapOk && pagerUseWal(pPager) ){
+    rc = sqlite3WalFindFrame(pPager->pWal, pgno, &iFrame);
+    if( rc!=SQLITE_OK ){
+      *ppPage = 0;
+      return rc;
+    }
+  }
+  if( bMmapOk && iFrame==0 ){
+    void *pData = 0;
+    rc = sqlite3OsFetch(pPager->fd,
+        (i64)(pgno-1) * pPager->pageSize, pPager->pageSize, &pData
+    );
+    if( rc==SQLITE_OK && pData ){
+      if( pPager->eState>PAGER_READER || pPager->tempFile ){
+        pPg = sqlite3PagerLookup(pPager, pgno);
+      }
+      if( pPg==0 ){
+        rc = pagerAcquireMapPage(pPager, pgno, pData, &pPg);
+      }else{
+        sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1)*pPager->pageSize, pData);
+      }
+      if( pPg ){
+        assert( rc==SQLITE_OK );
+        *ppPage = pPg;
+        return SQLITE_OK;
+      }
+    }
+    if( rc!=SQLITE_OK ){
+      *ppPage = 0;
+      return rc;
+    }
+  }
+  return getPageNormal(pPager, pgno, ppPage, flags);
+}
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+
+/* The page getter method for when the pager is an error state */
+static int getPageError(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int flags           /* PAGER_GET_XXX flags */
+){
+  UNUSED_PARAMETER(pgno);
+  UNUSED_PARAMETER(flags);
+  assert( pPager->errCode!=SQLITE_OK );
+  *ppPage = 0;
+  return pPager->errCode;
+}
+
+
+/* Dispatch all page fetch requests to the appropriate getter method.
+*/
+SQLITE_PRIVATE int sqlite3PagerGet(
+  Pager *pPager,      /* The pager open on the database file */
+  Pgno pgno,          /* Page number to fetch */
+  DbPage **ppPage,    /* Write a pointer to the page here */
+  int flags           /* PAGER_GET_XXX flags */
+){
+#if 0   /* Trace page fetch by setting to 1 */
+  int rc;
+  printf("PAGE %u\n", pgno);
+  fflush(stdout);
+  rc = pPager->xGet(pPager, pgno, ppPage, flags);
+  if( rc ){
+    printf("PAGE %u failed with 0x%02x\n", pgno, rc);
+    fflush(stdout);
+  }
+  return rc;
+#else
+  /* Normal, high-speed version of sqlite3PagerGet() */
+  return pPager->xGet(pPager, pgno, ppPage, flags);
+#endif
+}
+
+/*
+** Acquire a page if it is already in the in-memory cache.  Do
+** not read the page from disk.  Return a pointer to the page,
+** or 0 if the page is not in cache.
+**
+** See also sqlite3PagerGet().  The difference between this routine
+** and sqlite3PagerGet() is that _get() will go to the disk and read
+** in the page if the page is not already in cache.  This routine
+** returns NULL if the page is not in cache or if a disk I/O error
+** has ever happened.
+*/
+SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
+  sqlite3_pcache_page *pPage;
+  assert( pPager!=0 );
+  assert( pgno!=0 );
+  assert( pPager->pPCache!=0 );
+  pPage = sqlite3PcacheFetch(pPager->pPCache, pgno, 0);
+  assert( pPage==0 || pPager->hasHeldSharedLock );
+  if( pPage==0 ) return 0;
+  return sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pPage);
+}
+
+/*
+** Release a page reference.
+**
+** The sqlite3PagerUnref() and sqlite3PagerUnrefNotNull() may only be used
+** if we know that the page being released is not the last reference to page1.
+** The btree layer always holds page1 open until the end, so these first
+** two routines can be used to release any page other than BtShared.pPage1.
+** The assert() at tag-20230419-2 proves that this constraint is always
+** honored.
+**
+** Use sqlite3PagerUnrefPageOne() to release page1.  This latter routine
+** checks the total number of outstanding pages and if the number of
+** pages reaches zero it drops the database lock.
+*/
+SQLITE_PRIVATE void sqlite3PagerUnrefNotNull(DbPage *pPg){
+  TESTONLY( Pager *pPager = pPg->pPager; )
+  assert( pPg!=0 );
+  if( pPg->flags & PGHDR_MMAP ){
+    assert( pPg->pgno!=1 );  /* Page1 is never memory mapped */
+    pagerReleaseMapPage(pPg);
+  }else{
+    sqlite3PcacheRelease(pPg);
+  }
+  /* Do not use this routine to release the last reference to page1 */
+  assert( sqlite3PcacheRefCount(pPager->pPCache)>0 ); /* tag-20230419-2 */
+}
+SQLITE_PRIVATE void sqlite3PagerUnref(DbPage *pPg){
+  if( pPg ) sqlite3PagerUnrefNotNull(pPg);
+}
+SQLITE_PRIVATE void sqlite3PagerUnrefPageOne(DbPage *pPg){
+  Pager *pPager;
+  assert( pPg!=0 );
+  assert( pPg->pgno==1 );
+  assert( (pPg->flags & PGHDR_MMAP)==0 ); /* Page1 is never memory mapped */
+  pPager = pPg->pPager;
+  sqlite3PcacheRelease(pPg);
+  pagerUnlockIfUnused(pPager);
+}
+
+/*
+** This function is called at the start of every write transaction.
+** There must already be a RESERVED or EXCLUSIVE lock on the database
+** file when this routine is called.
+**
+** Open the journal file for pager pPager and write a journal header
+** to the start of it. If there are active savepoints, open the sub-journal
+** as well. This function is only used when the journal file is being
+** opened to write a rollback log for a transaction. It is not used
+** when opening a hot journal file to roll it back.
+**
+** If the journal file is already open (as it may be in exclusive mode),
+** then this function just writes a journal header to the start of the
+** already open file.
+**
+** Whether or not the journal file is opened by this function, the
+** Pager.pInJournal bitvec structure is allocated.
+**
+** Return SQLITE_OK if everything is successful. Otherwise, return
+** SQLITE_NOMEM if the attempt to allocate Pager.pInJournal fails, or
+** an IO error code if opening or writing the journal file fails.
+*/
+static int pager_open_journal(Pager *pPager){
+  int rc = SQLITE_OK;                        /* Return code */
+  sqlite3_vfs * const pVfs = pPager->pVfs;   /* Local cache of vfs pointer */
+
+  assert( pPager->eState==PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->pInJournal==0 );
+
+  /* If already in the error state, this function is a no-op.  But on
+  ** the other hand, this routine is never called if we are already in
+  ** an error state. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
+
+  if( !pagerUseWal(pPager) && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
+    pPager->pInJournal = sqlite3BitvecCreate(pPager->dbSize);
+    if( pPager->pInJournal==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+
+    /* Open the journal file if it is not already open. */
+    if( !isOpen(pPager->jfd) ){
+      if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
+        sqlite3MemJournalOpen(pPager->jfd);
+      }else{
+        int flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE;
+        int nSpill;
+
+        if( pPager->tempFile ){
+          flags |= (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL);
+          flags |= SQLITE_OPEN_EXCLUSIVE;
+          nSpill = sqlite3Config.nStmtSpill;
+        }else{
+          flags |= SQLITE_OPEN_MAIN_JOURNAL;
+          nSpill = jrnlBufferSize(pPager);
+        }
+
+        /* Verify that the database still has the same name as it did when
+        ** it was originally opened. */
+        rc = databaseIsUnmoved(pPager);
+        if( rc==SQLITE_OK ){
+          rc = sqlite3JournalOpen (
+              pVfs, pPager->zJournal, pPager->jfd, flags, nSpill
+          );
+        }
+      }
+      assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
+    }
+
+
+    /* Write the first journal header to the journal file and open
+    ** the sub-journal if necessary.
+    */
+    if( rc==SQLITE_OK ){
+      /* TODO: Check if all of these are really required. */
+      pPager->nRec = 0;
+      pPager->journalOff = 0;
+      pPager->setSuper = 0;
+      pPager->journalHdr = 0;
+      rc = writeJournalHdr(pPager);
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3BitvecDestroy(pPager->pInJournal);
+    pPager->pInJournal = 0;
+    pPager->journalOff = 0;
+  }else{
+    assert( pPager->eState==PAGER_WRITER_LOCKED );
+    pPager->eState = PAGER_WRITER_CACHEMOD;
+  }
+
+  return rc;
+}
+
+/*
+** Begin a write-transaction on the specified pager object. If a
+** write-transaction has already been opened, this function is a no-op.
+**
+** If the exFlag argument is false, then acquire at least a RESERVED
+** lock on the database file. If exFlag is true, then acquire at least
+** an EXCLUSIVE lock. If such a lock is already held, no locking
+** functions need be called.
+**
+** If the subjInMemory argument is non-zero, then any sub-journal opened
+** within this transaction will be opened as an in-memory file. This
+** has no effect if the sub-journal is already opened (as it may be when
+** running in exclusive mode) or if the transaction does not require a
+** sub-journal. If the subjInMemory argument is zero, then any required
+** sub-journal is implemented in-memory if pPager is an in-memory database,
+** or using a temporary file otherwise.
+*/
+SQLITE_PRIVATE int sqlite3PagerBegin(Pager *pPager, int exFlag, int subjInMemory){
+  int rc = SQLITE_OK;
+
+  if( pPager->errCode ) return pPager->errCode;
+  assert( pPager->eState>=PAGER_READER && pPager->eState<PAGER_ERROR );
+  pPager->subjInMemory = (u8)subjInMemory;
+
+  if( pPager->eState==PAGER_READER ){
+    assert( pPager->pInJournal==0 );
+
+    if( pagerUseWal(pPager) ){
+      /* If the pager is configured to use locking_mode=exclusive, and an
+      ** exclusive lock on the database is not already held, obtain it now.
+      */
+      if( pPager->exclusiveMode && sqlite3WalExclusiveMode(pPager->pWal, -1) ){
+        rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        (void)sqlite3WalExclusiveMode(pPager->pWal, 1);
+      }
+
+      /* Grab the write lock on the log file. If successful, upgrade to
+      ** PAGER_RESERVED state. Otherwise, return an error code to the caller.
+      ** The busy-handler is not invoked if another connection already
+      ** holds the write-lock. If possible, the upper layer will call it.
+      */
+      rc = sqlite3WalBeginWriteTransaction(pPager->pWal);
+    }else{
+      /* Obtain a RESERVED lock on the database file. If the exFlag parameter
+      ** is true, then immediately upgrade this to an EXCLUSIVE lock. The
+      ** busy-handler callback can be used when upgrading to the EXCLUSIVE
+      ** lock, but not when obtaining the RESERVED lock.
+      */
+      rc = pagerLockDb(pPager, RESERVED_LOCK);
+      if( rc==SQLITE_OK && exFlag ){
+        rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      /* Change to WRITER_LOCKED state.
+      **
+      ** WAL mode sets Pager.eState to PAGER_WRITER_LOCKED or CACHEMOD
+      ** when it has an open transaction, but never to DBMOD or FINISHED.
+      ** This is because in those states the code to roll back savepoint
+      ** transactions may copy data from the sub-journal into the database
+      ** file as well as into the page cache. Which would be incorrect in
+      ** WAL mode.
+      */
+      pPager->eState = PAGER_WRITER_LOCKED;
+      pPager->dbHintSize = pPager->dbSize;
+      pPager->dbFileSize = pPager->dbSize;
+      pPager->dbOrigSize = pPager->dbSize;
+      pPager->journalOff = 0;
+    }
+
+    assert( rc==SQLITE_OK || pPager->eState==PAGER_READER );
+    assert( rc!=SQLITE_OK || pPager->eState==PAGER_WRITER_LOCKED );
+    assert( assert_pager_state(pPager) );
+  }
+
+  PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
+  return rc;
+}
+
+/*
+** Write page pPg onto the end of the rollback journal.
+*/
+static SQLITE_NOINLINE int pagerAddPageToRollbackJournal(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  int rc;
+  u32 cksum;
+  char *pData2;
+  i64 iOff = pPager->journalOff;
+
+  /* We should never write to the journal file the page that
+  ** contains the database locks.  The following assert verifies
+  ** that we do not. */
+  assert( pPg->pgno!=PAGER_SJ_PGNO(pPager) );
+
+  assert( pPager->journalHdr<=pPager->journalOff );
+  pData2 = pPg->pData;
+  cksum = pager_cksum(pPager, (u8*)pData2);
+
+  /* Even if an IO or diskfull error occurs while journalling the
+  ** page in the block above, set the need-sync flag for the page.
+  ** Otherwise, when the transaction is rolled back, the logic in
+  ** playback_one_page() will think that the page needs to be restored
+  ** in the database file. And if an IO error occurs while doing so,
+  ** then corruption may follow.
+  */
+  pPg->flags |= PGHDR_NEED_SYNC;
+
+  rc = write32bits(pPager->jfd, iOff, pPg->pgno);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize, iOff+4);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = write32bits(pPager->jfd, iOff+pPager->pageSize+4, cksum);
+  if( rc!=SQLITE_OK ) return rc;
+
+  IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno,
+           pPager->journalOff, pPager->pageSize));
+  PAGER_INCR(sqlite3_pager_writej_count);
+  PAGERTRACE(("JOURNAL %d page %d needSync=%d hash(%08x)\n",
+       PAGERID(pPager), pPg->pgno,
+       ((pPg->flags&PGHDR_NEED_SYNC)?1:0), pager_pagehash(pPg)));
+
+  pPager->journalOff += 8 + pPager->pageSize;
+  pPager->nRec++;
+  assert( pPager->pInJournal!=0 );
+  rc = sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
+  testcase( rc==SQLITE_NOMEM );
+  assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+  rc |= addToSavepointBitvecs(pPager, pPg->pgno);
+  assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+  return rc;
+}
+
+/*
+** Mark a single data page as writeable. The page is written into the
+** main journal or sub-journal as required. If the page is written into
+** one of the journals, the corresponding bit is set in the
+** Pager.pInJournal bitvec and the PagerSavepoint.pInSavepoint bitvecs
+** of any open savepoints as appropriate.
+*/
+static int pager_write(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  int rc = SQLITE_OK;
+
+  /* This routine is not called unless a write-transaction has already
+  ** been started. The journal file may or may not be open at this point.
+  ** It is never called in the ERROR state.
+  */
+  assert( pPager->eState==PAGER_WRITER_LOCKED
+       || pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+  assert( pPager->errCode==0 );
+  assert( pPager->readOnly==0 );
+  CHECK_PAGE(pPg);
+
+  /* The journal file needs to be opened. Higher level routines have already
+  ** obtained the necessary locks to begin the write-transaction, but the
+  ** rollback journal might not yet be open. Open it now if this is the case.
+  **
+  ** This is done before calling sqlite3PcacheMakeDirty() on the page.
+  ** Otherwise, if it were done after calling sqlite3PcacheMakeDirty(), then
+  ** an error might occur and the pager would end up in WRITER_LOCKED state
+  ** with pages marked as dirty in the cache.
+  */
+  if( pPager->eState==PAGER_WRITER_LOCKED ){
+    rc = pager_open_journal(pPager);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  assert( pPager->eState>=PAGER_WRITER_CACHEMOD );
+  assert( assert_pager_state(pPager) );
+
+  /* Mark the page that is about to be modified as dirty. */
+  sqlite3PcacheMakeDirty(pPg);
+
+  /* If a rollback journal is in use, them make sure the page that is about
+  ** to change is in the rollback journal, or if the page is a new page off
+  ** then end of the file, make sure it is marked as PGHDR_NEED_SYNC.
+  */
+  assert( (pPager->pInJournal!=0) == isOpen(pPager->jfd) );
+  if( pPager->pInJournal!=0
+   && sqlite3BitvecTestNotNull(pPager->pInJournal, pPg->pgno)==0
+  ){
+    assert( pagerUseWal(pPager)==0 );
+    if( pPg->pgno<=pPager->dbOrigSize ){
+      rc = pagerAddPageToRollbackJournal(pPg);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }else{
+      if( pPager->eState!=PAGER_WRITER_DBMOD ){
+        pPg->flags |= PGHDR_NEED_SYNC;
+      }
+      PAGERTRACE(("APPEND %d page %d needSync=%d\n",
+              PAGERID(pPager), pPg->pgno,
+             ((pPg->flags&PGHDR_NEED_SYNC)?1:0)));
+    }
+  }
+
+  /* The PGHDR_DIRTY bit is set above when the page was added to the dirty-list
+  ** and before writing the page into the rollback journal.  Wait until now,
+  ** after the page has been successfully journalled, before setting the
+  ** PGHDR_WRITEABLE bit that indicates that the page can be safely modified.
+  */
+  pPg->flags |= PGHDR_WRITEABLE;
+
+  /* If the statement journal is open and the page is not in it,
+  ** then write the page into the statement journal.
+  */
+  if( pPager->nSavepoint>0 ){
+    rc = subjournalPageIfRequired(pPg);
+  }
+
+  /* Update the database size and return. */
+  if( pPager->dbSize<pPg->pgno ){
+    pPager->dbSize = pPg->pgno;
+  }
+  return rc;
+}
+
+/*
+** This is a variant of sqlite3PagerWrite() that runs when the sector size
+** is larger than the page size.  SQLite makes the (reasonable) assumption that
+** all bytes of a sector are written together by hardware.  Hence, all bytes of
+** a sector need to be journalled in case of a power loss in the middle of
+** a write.
+**
+** Usually, the sector size is less than or equal to the page size, in which
+** case pages can be individually written.  This routine only runs in the
+** exceptional case where the page size is smaller than the sector size.
+*/
+static SQLITE_NOINLINE int pagerWriteLargeSector(PgHdr *pPg){
+  int rc = SQLITE_OK;          /* Return code */
+  Pgno nPageCount;             /* Total number of pages in database file */
+  Pgno pg1;                    /* First page of the sector pPg is located on. */
+  int nPage = 0;               /* Number of pages starting at pg1 to journal */
+  int ii;                      /* Loop counter */
+  int needSync = 0;            /* True if any page has PGHDR_NEED_SYNC */
+  Pager *pPager = pPg->pPager; /* The pager that owns pPg */
+  Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);
+
+  /* Set the doNotSpill NOSYNC bit to 1. This is because we cannot allow
+  ** a journal header to be written between the pages journaled by
+  ** this function.
+  */
+  assert( !MEMDB );
+  assert( (pPager->doNotSpill & SPILLFLAG_NOSYNC)==0 );
+  pPager->doNotSpill |= SPILLFLAG_NOSYNC;
+
+  /* This trick assumes that both the page-size and sector-size are
+  ** an integer power of 2. It sets variable pg1 to the identifier
+  ** of the first page of the sector pPg is located on.
+  */
+  pg1 = ((pPg->pgno-1) & ~(nPagePerSector-1)) + 1;
+
+  nPageCount = pPager->dbSize;
+  if( pPg->pgno>nPageCount ){
+    nPage = (pPg->pgno - pg1)+1;
+  }else if( (pg1+nPagePerSector-1)>nPageCount ){
+    nPage = nPageCount+1-pg1;
+  }else{
+    nPage = nPagePerSector;
+  }
+  assert(nPage>0);
+  assert(pg1<=pPg->pgno);
+  assert((pg1+nPage)>pPg->pgno);
+
+  for(ii=0; ii<nPage && rc==SQLITE_OK; ii++){
+    Pgno pg = pg1+ii;
+    PgHdr *pPage;
+    if( pg==pPg->pgno || !sqlite3BitvecTest(pPager->pInJournal, pg) ){
+      if( pg!=PAGER_SJ_PGNO(pPager) ){
+        rc = sqlite3PagerGet(pPager, pg, &pPage, 0);
+        if( rc==SQLITE_OK ){
+          rc = pager_write(pPage);
+          if( pPage->flags&PGHDR_NEED_SYNC ){
+            needSync = 1;
+          }
+          sqlite3PagerUnrefNotNull(pPage);
+        }
+      }
+    }else if( (pPage = sqlite3PagerLookup(pPager, pg))!=0 ){
+      if( pPage->flags&PGHDR_NEED_SYNC ){
+        needSync = 1;
+      }
+      sqlite3PagerUnrefNotNull(pPage);
+    }
+  }
+
+  /* If the PGHDR_NEED_SYNC flag is set for any of the nPage pages
+  ** starting at pg1, then it needs to be set for all of them. Because
+  ** writing to any of these nPage pages may damage the others, the
+  ** journal file must contain sync()ed copies of all of them
+  ** before any of them can be written out to the database file.
+  */
+  if( rc==SQLITE_OK && needSync ){
+    assert( !MEMDB );
+    for(ii=0; ii<nPage; ii++){
+      PgHdr *pPage = sqlite3PagerLookup(pPager, pg1+ii);
+      if( pPage ){
+        pPage->flags |= PGHDR_NEED_SYNC;
+        sqlite3PagerUnrefNotNull(pPage);
+      }
+    }
+  }
+
+  assert( (pPager->doNotSpill & SPILLFLAG_NOSYNC)!=0 );
+  pPager->doNotSpill &= ~SPILLFLAG_NOSYNC;
+  return rc;
+}
+
+/*
+** Mark a data page as writeable. This routine must be called before
+** making changes to a page. The caller must check the return value
+** of this function and be careful not to change any page data unless
+** this routine returns SQLITE_OK.
+**
+** The difference between this function and pager_write() is that this
+** function also deals with the special case where 2 or more pages
+** fit on a single disk sector. In this case all co-resident pages
+** must have been written to the journal file before returning.
+**
+** If an error occurs, SQLITE_NOMEM or an IO error code is returned
+** as appropriate. Otherwise, SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3PagerWrite(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  assert( (pPg->flags & PGHDR_MMAP)==0 );
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
+  if( (pPg->flags & PGHDR_WRITEABLE)!=0 && pPager->dbSize>=pPg->pgno ){
+    if( pPager->nSavepoint ) return subjournalPageIfRequired(pPg);
+    return SQLITE_OK;
+  }else if( pPager->errCode ){
+    return pPager->errCode;
+  }else if( pPager->sectorSize > (u32)pPager->pageSize ){
+    assert( pPager->tempFile==0 );
+    return pagerWriteLargeSector(pPg);
+  }else{
+    return pager_write(pPg);
+  }
+}
+
+/*
+** Return TRUE if the page given in the argument was previously passed
+** to sqlite3PagerWrite().  In other words, return TRUE if it is ok
+** to change the content of the page.
+*/
+#ifndef NDEBUG
+SQLITE_PRIVATE int sqlite3PagerIswriteable(DbPage *pPg){
+  return pPg->flags & PGHDR_WRITEABLE;
+}
+#endif
+
+/*
+** A call to this routine tells the pager that it is not necessary to
+** write the information on page pPg back to the disk, even though
+** that page might be marked as dirty.  This happens, for example, when
+** the page has been added as a leaf of the freelist and so its
+** content no longer matters.
+**
+** The overlying software layer calls this routine when all of the data
+** on the given page is unused. The pager marks the page as clean so
+** that it does not get written to disk.
+**
+** Tests show that this optimization can quadruple the speed of large
+** DELETE operations.
+**
+** This optimization cannot be used with a temp-file, as the page may
+** have been dirty at the start of the transaction. In that case, if
+** memory pressure forces page pPg out of the cache, the data does need
+** to be written out to disk so that it may be read back in if the
+** current transaction is rolled back.
+*/
+SQLITE_PRIVATE void sqlite3PagerDontWrite(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  if( !pPager->tempFile && (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){
+    PAGERTRACE(("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager)));
+    IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
+    pPg->flags |= PGHDR_DONT_WRITE;
+    pPg->flags &= ~PGHDR_WRITEABLE;
+    testcase( pPg->flags & PGHDR_NEED_SYNC );
+    pager_set_pagehash(pPg);
+  }
+}
+
+/*
+** This routine is called to increment the value of the database file
+** change-counter, stored as a 4-byte big-endian integer starting at
+** byte offset 24 of the pager file.  The secondary change counter at
+** 92 is also updated, as is the SQLite version number at offset 96.
+**
+** But this only happens if the pPager->changeCountDone flag is false.
+** To avoid excess churning of page 1, the update only happens once.
+** See also the pager_write_changecounter() routine that does an
+** unconditional update of the change counters.
+**
+** If the isDirectMode flag is zero, then this is done by calling
+** sqlite3PagerWrite() on page 1, then modifying the contents of the
+** page data. In this case the file will be updated when the current
+** transaction is committed.
+**
+** The isDirectMode flag may only be non-zero if the library was compiled
+** with the SQLITE_ENABLE_ATOMIC_WRITE macro defined. In this case,
+** if isDirect is non-zero, then the database file is updated directly
+** by writing an updated version of page 1 using a call to the
+** sqlite3OsWrite() function.
+*/
+static int pager_incr_changecounter(Pager *pPager, int isDirectMode){
+  int rc = SQLITE_OK;
+
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* Declare and initialize constant integer 'isDirect'. If the
+  ** atomic-write optimization is enabled in this build, then isDirect
+  ** is initialized to the value passed as the isDirectMode parameter
+  ** to this function. Otherwise, it is always set to zero.
+  **
+  ** The idea is that if the atomic-write optimization is not
+  ** enabled at compile time, the compiler can omit the tests of
+  ** 'isDirect' below, as well as the block enclosed in the
+  ** "if( isDirect )" condition.
+  */
+#ifndef SQLITE_ENABLE_ATOMIC_WRITE
+# define DIRECT_MODE 0
+  assert( isDirectMode==0 );
+  UNUSED_PARAMETER(isDirectMode);
+#else
+# define DIRECT_MODE isDirectMode
+#endif
+
+  if( !pPager->changeCountDone && pPager->dbSize>0 ){
+    PgHdr *pPgHdr;                /* Reference to page 1 */
+
+    assert( !pPager->tempFile && isOpen(pPager->fd) );
+
+    /* Open page 1 of the file for writing. */
+    rc = sqlite3PagerGet(pPager, 1, &pPgHdr, 0);
+    assert( pPgHdr==0 || rc==SQLITE_OK );
+
+    /* If page one was fetched successfully, and this function is not
+    ** operating in direct-mode, make page 1 writable.  When not in
+    ** direct mode, page 1 is always held in cache and hence the PagerGet()
+    ** above is always successful - hence the ALWAYS on rc==SQLITE_OK.
+    */
+    if( !DIRECT_MODE && ALWAYS(rc==SQLITE_OK) ){
+      rc = sqlite3PagerWrite(pPgHdr);
+    }
+
+    if( rc==SQLITE_OK ){
+      /* Actually do the update of the change counter */
+      pager_write_changecounter(pPgHdr);
+
+      /* If running in direct mode, write the contents of page 1 to the file. */
+      if( DIRECT_MODE ){
+        const void *zBuf;
+        assert( pPager->dbFileSize>0 );
+        zBuf = pPgHdr->pData;
+        if( rc==SQLITE_OK ){
+          rc = sqlite3OsWrite(pPager->fd, zBuf, pPager->pageSize, 0);
+          pPager->aStat[PAGER_STAT_WRITE]++;
+        }
+        if( rc==SQLITE_OK ){
+          /* Update the pager's copy of the change-counter. Otherwise, the
+          ** next time a read transaction is opened the cache will be
+          ** flushed (as the change-counter values will not match).  */
+          const void *pCopy = (const void *)&((const char *)zBuf)[24];
+          memcpy(&pPager->dbFileVers, pCopy, sizeof(pPager->dbFileVers));
+          pPager->changeCountDone = 1;
+        }
+      }else{
+        pPager->changeCountDone = 1;
+      }
+    }
+
+    /* Release the page reference. */
+    sqlite3PagerUnref(pPgHdr);
+  }
+  return rc;
+}
+
+/*
+** Sync the database file to disk. This is a no-op for in-memory databases
+** or pages with the Pager.noSync flag set.
+**
+** If successful, or if called on a pager for which it is a no-op, this
+** function returns SQLITE_OK. Otherwise, an IO error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager, const char *zSuper){
+  int rc = SQLITE_OK;
+  void *pArg = (void*)zSuper;
+  rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_SYNC, pArg);
+  if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+  if( rc==SQLITE_OK && !pPager->noSync ){
+    assert( !MEMDB );
+    rc = sqlite3OsSync(pPager->fd, pPager->syncFlags);
+  }
+  return rc;
+}
+
+/*
+** This function may only be called while a write-transaction is active in
+** rollback. If the connection is in WAL mode, this call is a no-op.
+** Otherwise, if the connection does not already have an EXCLUSIVE lock on
+** the database file, an attempt is made to obtain one.
+**
+** If the EXCLUSIVE lock is already held or the attempt to obtain it is
+** successful, or the connection is in WAL mode, SQLITE_OK is returned.
+** Otherwise, either SQLITE_BUSY or an SQLITE_IOERR_XXX error code is
+** returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerExclusiveLock(Pager *pPager){
+  int rc = pPager->errCode;
+  assert( assert_pager_state(pPager) );
+  if( rc==SQLITE_OK ){
+    assert( pPager->eState==PAGER_WRITER_CACHEMOD
+         || pPager->eState==PAGER_WRITER_DBMOD
+         || pPager->eState==PAGER_WRITER_LOCKED
+    );
+    assert( assert_pager_state(pPager) );
+    if( 0==pagerUseWal(pPager) ){
+      rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
+    }
+  }
+  return rc;
+}
+
+/*
+** Sync the database file for the pager pPager. zSuper points to the name
+** of a super-journal file that should be written into the individual
+** journal file. zSuper may be NULL, which is interpreted as no
+** super-journal (a single database transaction).
+**
+** This routine ensures that:
+**
+**   * The database file change-counter is updated,
+**   * the journal is synced (unless the atomic-write optimization is used),
+**   * all dirty pages are written to the database file,
+**   * the database file is truncated (if required), and
+**   * the database file synced.
+**
+** The only thing that remains to commit the transaction is to finalize
+** (delete, truncate or zero the first part of) the journal file (or
+** delete the super-journal file if specified).
+**
+** Note that if zSuper==NULL, this does not overwrite a previous value
+** passed to an sqlite3PagerCommitPhaseOne() call.
+**
+** If the final parameter - noSync - is true, then the database file itself
+** is not synced. The caller must call sqlite3PagerSync() directly to
+** sync the database file before calling CommitPhaseTwo() to delete the
+** journal file in this case.
+*/
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(
+  Pager *pPager,                  /* Pager object */
+  const char *zSuper,            /* If not NULL, the super-journal name */
+  int noSync                      /* True to omit the xSync on the db file */
+){
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( pPager->eState==PAGER_WRITER_LOCKED
+       || pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+       || pPager->eState==PAGER_ERROR
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* If a prior error occurred, report that error again. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
+
+  /* Provide the ability to easily simulate an I/O error during testing */
+  if( sqlite3FaultSim(400) ) return SQLITE_IOERR;
+
+  PAGERTRACE(("DATABASE SYNC: File=%s zSuper=%s nSize=%d\n",
+      pPager->zFilename, zSuper, pPager->dbSize));
+
+  /* If no database changes have been made, return early. */
+  if( pPager->eState<PAGER_WRITER_CACHEMOD ) return SQLITE_OK;
+
+  assert( MEMDB==0 || pPager->tempFile );
+  assert( isOpen(pPager->fd) || pPager->tempFile );
+  if( 0==pagerFlushOnCommit(pPager, 1) ){
+    /* If this is an in-memory db, or no pages have been written to, or this
+    ** function has already been called, it is mostly a no-op.  However, any
+    ** backup in progress needs to be restarted.  */
+    sqlite3BackupRestart(pPager->pBackup);
+  }else{
+    PgHdr *pList;
+    if( pagerUseWal(pPager) ){
+      PgHdr *pPageOne = 0;
+      pList = sqlite3PcacheDirtyList(pPager->pPCache);
+      if( pList==0 ){
+        /* Must have at least one page for the WAL commit flag.
+        ** Ticket [2d1a5c67dfc2363e44f29d9bbd57f] 2011-05-18 */
+        rc = sqlite3PagerGet(pPager, 1, &pPageOne, 0);
+        pList = pPageOne;
+        pList->pDirty = 0;
+      }
+      assert( rc==SQLITE_OK );
+      if( ALWAYS(pList) ){
+        rc = pagerWalFrames(pPager, pList, pPager->dbSize, 1);
+      }
+      sqlite3PagerUnref(pPageOne);
+      if( rc==SQLITE_OK ){
+        sqlite3PcacheCleanAll(pPager->pPCache);
+      }
+    }else{
+      /* The bBatch boolean is true if the batch-atomic-write commit method
+      ** should be used.  No rollback journal is created if batch-atomic-write
+      ** is enabled.
+      */
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+      sqlite3_file *fd = pPager->fd;
+      int bBatch = zSuper==0    /* An SQLITE_IOCAP_BATCH_ATOMIC commit */
+        && (sqlite3OsDeviceCharacteristics(fd) & SQLITE_IOCAP_BATCH_ATOMIC)
+        && !pPager->noSync
+        && sqlite3JournalIsInMemory(pPager->jfd);
+#else
+#     define bBatch 0
+#endif
+
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+      /* The following block updates the change-counter. Exactly how it
+      ** does this depends on whether or not the atomic-update optimization
+      ** was enabled at compile time, and if this transaction meets the
+      ** runtime criteria to use the operation:
+      **
+      **    * The file-system supports the atomic-write property for
+      **      blocks of size page-size, and
+      **    * This commit is not part of a multi-file transaction, and
+      **    * Exactly one page has been modified and store in the journal file.
+      **
+      ** If the optimization was not enabled at compile time, then the
+      ** pager_incr_changecounter() function is called to update the change
+      ** counter in 'indirect-mode'. If the optimization is compiled in but
+      ** is not applicable to this transaction, call sqlite3JournalCreate()
+      ** to make sure the journal file has actually been created, then call
+      ** pager_incr_changecounter() to update the change-counter in indirect
+      ** mode.
+      **
+      ** Otherwise, if the optimization is both enabled and applicable,
+      ** then call pager_incr_changecounter() to update the change-counter
+      ** in 'direct' mode. In this case the journal file will never be
+      ** created for this transaction.
+      */
+      if( bBatch==0 ){
+        PgHdr *pPg;
+        assert( isOpen(pPager->jfd)
+            || pPager->journalMode==PAGER_JOURNALMODE_OFF
+            || pPager->journalMode==PAGER_JOURNALMODE_WAL
+            );
+        if( !zSuper && isOpen(pPager->jfd)
+         && pPager->journalOff==jrnlBufferSize(pPager)
+         && pPager->dbSize>=pPager->dbOrigSize
+         && (!(pPg = sqlite3PcacheDirtyList(pPager->pPCache)) || 0==pPg->pDirty)
+        ){
+          /* Update the db file change counter via the direct-write method. The
+          ** following call will modify the in-memory representation of page 1
+          ** to include the updated change counter and then write page 1
+          ** directly to the database file. Because of the atomic-write
+          ** property of the host file-system, this is safe.
+          */
+          rc = pager_incr_changecounter(pPager, 1);
+        }else{
+          rc = sqlite3JournalCreate(pPager->jfd);
+          if( rc==SQLITE_OK ){
+            rc = pager_incr_changecounter(pPager, 0);
+          }
+        }
+      }
+#else  /* SQLITE_ENABLE_ATOMIC_WRITE */
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+      if( zSuper ){
+        rc = sqlite3JournalCreate(pPager->jfd);
+        if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+        assert( bBatch==0 );
+      }
+#endif
+      rc = pager_incr_changecounter(pPager, 0);
+#endif /* !SQLITE_ENABLE_ATOMIC_WRITE */
+      if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+
+      /* Write the super-journal name into the journal file. If a
+      ** super-journal file name has already been written to the journal file,
+      ** or if zSuper is NULL (no super-journal), then this call is a no-op.
+      */
+      rc = writeSuperJournal(pPager, zSuper);
+      if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+
+      /* Sync the journal file and write all dirty pages to the database.
+      ** If the atomic-update optimization is being used, this sync will not
+      ** create the journal file or perform any real IO.
+      **
+      ** Because the change-counter page was just modified, unless the
+      ** atomic-update optimization is used it is almost certain that the
+      ** journal requires a sync here. However, in locking_mode=exclusive
+      ** on a system under memory pressure it is just possible that this is
+      ** not the case. In this case it is likely enough that the redundant
+      ** xSync() call will be changed to a no-op by the OS anyhow.
+      */
+      rc = syncJournal(pPager, 0);
+      if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+
+      pList = sqlite3PcacheDirtyList(pPager->pPCache);
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+      if( bBatch ){
+        rc = sqlite3OsFileControl(fd, SQLITE_FCNTL_BEGIN_ATOMIC_WRITE, 0);
+        if( rc==SQLITE_OK ){
+          rc = pager_write_pagelist(pPager, pList);
+          if( rc==SQLITE_OK && pPager->dbSize>pPager->dbFileSize ){
+            char *pTmp = pPager->pTmpSpace;
+            int szPage = (int)pPager->pageSize;
+            memset(pTmp, 0, szPage);
+            rc = sqlite3OsWrite(pPager->fd, pTmp, szPage,
+                      ((i64)pPager->dbSize*pPager->pageSize)-szPage);
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3OsFileControl(fd, SQLITE_FCNTL_COMMIT_ATOMIC_WRITE, 0);
+          }
+          if( rc!=SQLITE_OK ){
+            sqlite3OsFileControlHint(fd, SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE, 0);
+          }
+        }
+
+        if( (rc&0xFF)==SQLITE_IOERR && rc!=SQLITE_IOERR_NOMEM ){
+          rc = sqlite3JournalCreate(pPager->jfd);
+          if( rc!=SQLITE_OK ){
+            sqlite3OsClose(pPager->jfd);
+            goto commit_phase_one_exit;
+          }
+          bBatch = 0;
+        }else{
+          sqlite3OsClose(pPager->jfd);
+        }
+      }
+#endif /* SQLITE_ENABLE_BATCH_ATOMIC_WRITE */
+
+      if( bBatch==0 ){
+        rc = pager_write_pagelist(pPager, pList);
+      }
+      if( rc!=SQLITE_OK ){
+        assert( rc!=SQLITE_IOERR_BLOCKED );
+        goto commit_phase_one_exit;
+      }
+      sqlite3PcacheCleanAll(pPager->pPCache);
+
+      /* If the file on disk is smaller than the database image, use
+      ** pager_truncate to grow the file here. This can happen if the database
+      ** image was extended as part of the current transaction and then the
+      ** last page in the db image moved to the free-list. In this case the
+      ** last page is never written out to disk, leaving the database file
+      ** undersized. Fix this now if it is the case.  */
+      if( pPager->dbSize>pPager->dbFileSize ){
+        Pgno nNew = pPager->dbSize - (pPager->dbSize==PAGER_SJ_PGNO(pPager));
+        assert( pPager->eState==PAGER_WRITER_DBMOD );
+        rc = pager_truncate(pPager, nNew);
+        if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
+      }
+
+      /* Finally, sync the database file. */
+      if( !noSync ){
+        rc = sqlite3PagerSync(pPager, zSuper);
+      }
+      IOTRACE(("DBSYNC %p\n", pPager))
+    }
+  }
+
+commit_phase_one_exit:
+  if( rc==SQLITE_OK && !pagerUseWal(pPager) ){
+    pPager->eState = PAGER_WRITER_FINISHED;
+  }
+  return rc;
+}
+
+
+/*
+** When this function is called, the database file has been completely
+** updated to reflect the changes made by the current transaction and
+** synced to disk. The journal file still exists in the file-system
+** though, and if a failure occurs at this point it will eventually
+** be used as a hot-journal and the current transaction rolled back.
+**
+** This function finalizes the journal file, either by deleting,
+** truncating or partially zeroing it, so that it cannot be used
+** for hot-journal rollback. Once this is done the transaction is
+** irrevocably committed.
+**
+** If an error occurs, an IO error code is returned and the pager
+** moves into the error state. Otherwise, SQLITE_OK is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager *pPager){
+  int rc = SQLITE_OK;                  /* Return code */
+
+  /* This routine should not be called if a prior error has occurred.
+  ** But if (due to a coding error elsewhere in the system) it does get
+  ** called, just return the same error code without doing anything. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
+  pPager->iDataVersion++;
+
+  assert( pPager->eState==PAGER_WRITER_LOCKED
+       || pPager->eState==PAGER_WRITER_FINISHED
+       || (pagerUseWal(pPager) && pPager->eState==PAGER_WRITER_CACHEMOD)
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* An optimization. If the database was not actually modified during
+  ** this transaction, the pager is running in exclusive-mode and is
+  ** using persistent journals, then this function is a no-op.
+  **
+  ** The start of the journal file currently contains a single journal
+  ** header with the nRec field set to 0. If such a journal is used as
+  ** a hot-journal during hot-journal rollback, 0 changes will be made
+  ** to the database file. So there is no need to zero the journal
+  ** header. Since the pager is in exclusive mode, there is no need
+  ** to drop any locks either.
+  */
+  if( pPager->eState==PAGER_WRITER_LOCKED
+   && pPager->exclusiveMode
+   && pPager->journalMode==PAGER_JOURNALMODE_PERSIST
+  ){
+    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) || !pPager->journalOff );
+    pPager->eState = PAGER_READER;
+    return SQLITE_OK;
+  }
+
+  PAGERTRACE(("COMMIT %d\n", PAGERID(pPager)));
+  rc = pager_end_transaction(pPager, pPager->setSuper, 1);
+  return pager_error(pPager, rc);
+}
+
+/*
+** If a write transaction is open, then all changes made within the
+** transaction are reverted and the current write-transaction is closed.
+** The pager falls back to PAGER_READER state if successful, or PAGER_ERROR
+** state if an error occurs.
+**
+** If the pager is already in PAGER_ERROR state when this function is called,
+** it returns Pager.errCode immediately. No work is performed in this case.
+**
+** Otherwise, in rollback mode, this function performs two functions:
+**
+**   1) It rolls back the journal file, restoring all database file and
+**      in-memory cache pages to the state they were in when the transaction
+**      was opened, and
+**
+**   2) It finalizes the journal file, so that it is not used for hot
+**      rollback at any point in the future.
+**
+** Finalization of the journal file (task 2) is only performed if the
+** rollback is successful.
+**
+** In WAL mode, all cache-entries containing data modified within the
+** current transaction are either expelled from the cache or reverted to
+** their pre-transaction state by re-reading data from the database or
+** WAL files. The WAL transaction is then closed.
+*/
+SQLITE_PRIVATE int sqlite3PagerRollback(Pager *pPager){
+  int rc = SQLITE_OK;                  /* Return code */
+  PAGERTRACE(("ROLLBACK %d\n", PAGERID(pPager)));
+
+  /* PagerRollback() is a no-op if called in READER or OPEN state. If
+  ** the pager is already in the ERROR state, the rollback is not
+  ** attempted here. Instead, the error code is returned to the caller.
+  */
+  assert( assert_pager_state(pPager) );
+  if( pPager->eState==PAGER_ERROR ) return pPager->errCode;
+  if( pPager->eState<=PAGER_READER ) return SQLITE_OK;
+
+  if( pagerUseWal(pPager) ){
+    int rc2;
+    rc = sqlite3PagerSavepoint(pPager, SAVEPOINT_ROLLBACK, -1);
+    rc2 = pager_end_transaction(pPager, pPager->setSuper, 0);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }else if( !isOpen(pPager->jfd) || pPager->eState==PAGER_WRITER_LOCKED ){
+    int eState = pPager->eState;
+    rc = pager_end_transaction(pPager, 0, 0);
+    if( !MEMDB && eState>PAGER_WRITER_LOCKED ){
+      /* This can happen using journal_mode=off. Move the pager to the error
+      ** state to indicate that the contents of the cache may not be trusted.
+      ** Any active readers will get SQLITE_ABORT.
+      */
+      pPager->errCode = SQLITE_ABORT;
+      pPager->eState = PAGER_ERROR;
+      setGetterMethod(pPager);
+      return rc;
+    }
+  }else{
+    rc = pager_playback(pPager, 0);
+  }
+
+  assert( pPager->eState==PAGER_READER || rc!=SQLITE_OK );
+  assert( rc==SQLITE_OK || rc==SQLITE_FULL || rc==SQLITE_CORRUPT
+          || rc==SQLITE_NOMEM || (rc&0xFF)==SQLITE_IOERR
+          || rc==SQLITE_CANTOPEN
+  );
+
+  /* If an error occurs during a ROLLBACK, we can no longer trust the pager
+  ** cache. So call pager_error() on the way out to make any error persistent.
+  */
+  return pager_error(pPager, rc);
+}
+
+/*
+** Return TRUE if the database file is opened read-only.  Return FALSE
+** if the database is (in theory) writable.
+*/
+SQLITE_PRIVATE u8 sqlite3PagerIsreadonly(Pager *pPager){
+  return pPager->readOnly;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Return the sum of the reference counts for all pages held by pPager.
+*/
+SQLITE_PRIVATE int sqlite3PagerRefcount(Pager *pPager){
+  return sqlite3PcacheRefCount(pPager->pPCache);
+}
+#endif
+
+/*
+** Return the approximate number of bytes of memory currently
+** used by the pager and its associated cache.
+*/
+SQLITE_PRIVATE int sqlite3PagerMemUsed(Pager *pPager){
+  int perPageSize = pPager->pageSize + pPager->nExtra
+    + (int)(sizeof(PgHdr) + 5*sizeof(void*));
+  return perPageSize*sqlite3PcachePagecount(pPager->pPCache)
+           + sqlite3MallocSize(pPager)
+           + pPager->pageSize;
+}
+
+/*
+** Return the number of references to the specified page.
+*/
+SQLITE_PRIVATE int sqlite3PagerPageRefcount(DbPage *pPage){
+  return sqlite3PcachePageRefcount(pPage);
+}
+
+#ifdef SQLITE_TEST
+/*
+** This routine is used for testing and analysis only.
+*/
+SQLITE_PRIVATE int *sqlite3PagerStats(Pager *pPager){
+  static int a[11];
+  a[0] = sqlite3PcacheRefCount(pPager->pPCache);
+  a[1] = sqlite3PcachePagecount(pPager->pPCache);
+  a[2] = sqlite3PcacheGetCachesize(pPager->pPCache);
+  a[3] = pPager->eState==PAGER_OPEN ? -1 : (int) pPager->dbSize;
+  a[4] = pPager->eState;
+  a[5] = pPager->errCode;
+  a[6] = (int)pPager->aStat[PAGER_STAT_HIT] & 0x7fffffff;
+  a[7] = (int)pPager->aStat[PAGER_STAT_MISS] & 0x7fffffff;
+  a[8] = 0;  /* Used to be pPager->nOvfl */
+  a[9] = pPager->nRead;
+  a[10] = (int)pPager->aStat[PAGER_STAT_WRITE] & 0x7fffffff;
+  return a;
+}
+#endif
+
+/*
+** Parameter eStat must be one of SQLITE_DBSTATUS_CACHE_HIT, _MISS, _WRITE,
+** or _WRITE+1.  The SQLITE_DBSTATUS_CACHE_WRITE+1 case is a translation
+** of SQLITE_DBSTATUS_CACHE_SPILL.  The _SPILL case is not contiguous because
+** it was added later.
+**
+** Before returning, *pnVal is incremented by the
+** current cache hit or miss count, according to the value of eStat. If the
+** reset parameter is non-zero, the cache hit or miss count is zeroed before
+** returning.
+*/
+SQLITE_PRIVATE void sqlite3PagerCacheStat(Pager *pPager, int eStat, int reset, u64 *pnVal){
+
+  assert( eStat==SQLITE_DBSTATUS_CACHE_HIT
+       || eStat==SQLITE_DBSTATUS_CACHE_MISS
+       || eStat==SQLITE_DBSTATUS_CACHE_WRITE
+       || eStat==SQLITE_DBSTATUS_CACHE_WRITE+1
+  );
+
+  assert( SQLITE_DBSTATUS_CACHE_HIT+1==SQLITE_DBSTATUS_CACHE_MISS );
+  assert( SQLITE_DBSTATUS_CACHE_HIT+2==SQLITE_DBSTATUS_CACHE_WRITE );
+  assert( PAGER_STAT_HIT==0 && PAGER_STAT_MISS==1
+           && PAGER_STAT_WRITE==2 && PAGER_STAT_SPILL==3 );
+
+  eStat -= SQLITE_DBSTATUS_CACHE_HIT;
+  *pnVal += pPager->aStat[eStat];
+  if( reset ){
+    pPager->aStat[eStat] = 0;
+  }
+}
+
+/*
+** Return true if this is an in-memory or temp-file backed pager.
+*/
+SQLITE_PRIVATE int sqlite3PagerIsMemdb(Pager *pPager){
+  return pPager->tempFile || pPager->memVfs;
+}
+
+/*
+** Check that there are at least nSavepoint savepoints open. If there are
+** currently less than nSavepoints open, then open one or more savepoints
+** to make up the difference. If the number of savepoints is already
+** equal to nSavepoint, then this function is a no-op.
+**
+** If a memory allocation fails, SQLITE_NOMEM is returned. If an error
+** occurs while opening the sub-journal file, then an IO error code is
+** returned. Otherwise, SQLITE_OK.
+*/
+static SQLITE_NOINLINE int pagerOpenSavepoint(Pager *pPager, int nSavepoint){
+  int rc = SQLITE_OK;                       /* Return code */
+  int nCurrent = pPager->nSavepoint;        /* Current number of savepoints */
+  int ii;                                   /* Iterator variable */
+  PagerSavepoint *aNew;                     /* New Pager.aSavepoint array */
+
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
+  assert( nSavepoint>nCurrent && pPager->useJournal );
+
+  /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
+  ** if the allocation fails. Otherwise, zero the new portion in case a
+  ** malloc failure occurs while populating it in the for(...) loop below.
+  */
+  aNew = (PagerSavepoint *)sqlite3Realloc(
+      pPager->aSavepoint, sizeof(PagerSavepoint)*nSavepoint
+  );
+  if( !aNew ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  memset(&aNew[nCurrent], 0, (nSavepoint-nCurrent) * sizeof(PagerSavepoint));
+  pPager->aSavepoint = aNew;
+
+  /* Populate the PagerSavepoint structures just allocated. */
+  for(ii=nCurrent; ii<nSavepoint; ii++){
+    aNew[ii].nOrig = pPager->dbSize;
+    if( isOpen(pPager->jfd) && pPager->journalOff>0 ){
+      aNew[ii].iOffset = pPager->journalOff;
+    }else{
+      aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
+    }
+    aNew[ii].iSubRec = pPager->nSubRec;
+    aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
+    aNew[ii].bTruncateOnRelease = 1;
+    if( !aNew[ii].pInSavepoint ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    if( pagerUseWal(pPager) ){
+      sqlite3WalSavepoint(pPager->pWal, aNew[ii].aWalData);
+    }
+    pPager->nSavepoint = ii+1;
+  }
+  assert( pPager->nSavepoint==nSavepoint );
+  assertTruncateConstraint(pPager);
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
+  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( assert_pager_state(pPager) );
+
+  if( nSavepoint>pPager->nSavepoint && pPager->useJournal ){
+    return pagerOpenSavepoint(pPager, nSavepoint);
+  }else{
+    return SQLITE_OK;
+  }
+}
+
+
+/*
+** This function is called to rollback or release (commit) a savepoint.
+** The savepoint to release or rollback need not be the most recently
+** created savepoint.
+**
+** Parameter op is always either SAVEPOINT_ROLLBACK or SAVEPOINT_RELEASE.
+** If it is SAVEPOINT_RELEASE, then release and destroy the savepoint with
+** index iSavepoint. If it is SAVEPOINT_ROLLBACK, then rollback all changes
+** that have occurred since the specified savepoint was created.
+**
+** The savepoint to rollback or release is identified by parameter
+** iSavepoint. A value of 0 means to operate on the outermost savepoint
+** (the first created). A value of (Pager.nSavepoint-1) means operate
+** on the most recently created savepoint. If iSavepoint is greater than
+** (Pager.nSavepoint-1), then this function is a no-op.
+**
+** If a negative value is passed to this function, then the current
+** transaction is rolled back. This is different to calling
+** sqlite3PagerRollback() because this function does not terminate
+** the transaction or unlock the database, it just restores the
+** contents of the database to its original state.
+**
+** In any case, all savepoints with an index greater than iSavepoint
+** are destroyed. If this is a release operation (op==SAVEPOINT_RELEASE),
+** then savepoint iSavepoint is also destroyed.
+**
+** This function may return SQLITE_NOMEM if a memory allocation fails,
+** or an IO error code if an IO error occurs while rolling back a
+** savepoint. If no errors occur, SQLITE_OK is returned.
+*/
+SQLITE_PRIVATE int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint){
+  int rc = pPager->errCode;
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+  if( op==SAVEPOINT_RELEASE ) rc = SQLITE_OK;
+#endif
+
+  assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
+  assert( iSavepoint>=0 || op==SAVEPOINT_ROLLBACK );
+
+  if( rc==SQLITE_OK && iSavepoint<pPager->nSavepoint ){
+    int ii;            /* Iterator variable */
+    int nNew;          /* Number of remaining savepoints after this op. */
+
+    /* Figure out how many savepoints will still be active after this
+    ** operation. Store this value in nNew. Then free resources associated
+    ** with any savepoints that are destroyed by this operation.
+    */
+    nNew = iSavepoint + (( op==SAVEPOINT_RELEASE ) ? 0 : 1);
+    for(ii=nNew; ii<pPager->nSavepoint; ii++){
+      sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
+    }
+    pPager->nSavepoint = nNew;
+
+    /* Truncate the sub-journal so that it only includes the parts
+    ** that are still in use. */
+    if( op==SAVEPOINT_RELEASE ){
+      PagerSavepoint *pRel = &pPager->aSavepoint[nNew];
+      if( pRel->bTruncateOnRelease && isOpen(pPager->sjfd) ){
+        /* Only truncate if it is an in-memory sub-journal. */
+        if( sqlite3JournalIsInMemory(pPager->sjfd) ){
+          i64 sz = (pPager->pageSize+4)*(i64)pRel->iSubRec;
+          rc = sqlite3OsTruncate(pPager->sjfd, sz);
+          assert( rc==SQLITE_OK );
+        }
+        pPager->nSubRec = pRel->iSubRec;
+      }
+    }
+    /* Else this is a rollback operation, playback the specified savepoint.
+    ** If this is a temp-file, it is possible that the journal file has
+    ** not yet been opened. In this case there have been no changes to
+    ** the database file, so the playback operation can be skipped.
+    */
+    else if( pagerUseWal(pPager) || isOpen(pPager->jfd) ){
+      PagerSavepoint *pSavepoint = (nNew==0)?0:&pPager->aSavepoint[nNew-1];
+      rc = pagerPlaybackSavepoint(pPager, pSavepoint);
+      assert(rc!=SQLITE_DONE);
+    }
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+    /* If the cache has been modified but the savepoint cannot be rolled
+    ** back journal_mode=off, put the pager in the error state. This way,
+    ** if the VFS used by this pager includes ZipVFS, the entire transaction
+    ** can be rolled back at the ZipVFS level.  */
+    else if(
+        pPager->journalMode==PAGER_JOURNALMODE_OFF
+     && pPager->eState>=PAGER_WRITER_CACHEMOD
+    ){
+      pPager->errCode = SQLITE_ABORT;
+      pPager->eState = PAGER_ERROR;
+      setGetterMethod(pPager);
+    }
+#endif
+  }
+
+  return rc;
+}
+
+/*
+** Return the full pathname of the database file.
+**
+** Except, if the pager is in-memory only, then return an empty string if
+** nullIfMemDb is true.  This routine is called with nullIfMemDb==1 when
+** used to report the filename to the user, for compatibility with legacy
+** behavior.  But when the Btree needs to know the filename for matching to
+** shared cache, it uses nullIfMemDb==0 so that in-memory databases can
+** participate in shared-cache.
+**
+** The return value to this routine is always safe to use with
+** sqlite3_uri_parameter() and sqlite3_filename_database() and friends.
+*/
+SQLITE_PRIVATE const char *sqlite3PagerFilename(const Pager *pPager, int nullIfMemDb){
+  static const char zFake[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
+  if( nullIfMemDb && (pPager->memDb || sqlite3IsMemdb(pPager->pVfs)) ){
+    return &zFake[4];
+  }else{
+    return pPager->zFilename;
+  }
+}
+
+/*
+** Return the VFS structure for the pager.
+*/
+SQLITE_PRIVATE sqlite3_vfs *sqlite3PagerVfs(Pager *pPager){
+  return pPager->pVfs;
+}
+
+/*
+** Return the file handle for the database file associated
+** with the pager.  This might return NULL if the file has
+** not yet been opened.
+*/
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerFile(Pager *pPager){
+  return pPager->fd;
+}
+
+/*
+** Return the file handle for the journal file (if it exists).
+** This will be either the rollback journal or the WAL file.
+*/
+SQLITE_PRIVATE sqlite3_file *sqlite3PagerJrnlFile(Pager *pPager){
+#ifdef SQLITE_OMIT_WAL
+  return pPager->jfd;
+#else
+  return pPager->pWal ? sqlite3WalFile(pPager->pWal) : pPager->jfd;
+#endif
+}
+
+/*
+** Return the full pathname of the journal file.
+*/
+SQLITE_PRIVATE const char *sqlite3PagerJournalname(Pager *pPager){
+  return pPager->zJournal;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Move the page pPg to location pgno in the file.
+**
+** There must be no references to the page previously located at
+** pgno (which we call pPgOld) though that page is allowed to be
+** in cache.  If the page previously located at pgno is not already
+** in the rollback journal, it is not put there by by this routine.
+**
+** References to the page pPg remain valid. Updating any
+** meta-data associated with pPg (i.e. data stored in the nExtra bytes
+** allocated along with the page) is the responsibility of the caller.
+**
+** A transaction must be active when this routine is called. It used to be
+** required that a statement transaction was not active, but this restriction
+** has been removed (CREATE INDEX needs to move a page when a statement
+** transaction is active).
+**
+** If the fourth argument, isCommit, is non-zero, then this page is being
+** moved as part of a database reorganization just before the transaction
+** is being committed. In this case, it is guaranteed that the database page
+** pPg refers to will not be written to again within this transaction.
+**
+** This function may return SQLITE_NOMEM or an IO error code if an error
+** occurs. Otherwise, it returns SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
+  PgHdr *pPgOld;               /* The page being overwritten. */
+  Pgno needSyncPgno = 0;       /* Old value of pPg->pgno, if sync is required */
+  int rc;                      /* Return code */
+  Pgno origPgno;               /* The original page number */
+
+  assert( pPg->nRef>0 );
+  assert( pPager->eState==PAGER_WRITER_CACHEMOD
+       || pPager->eState==PAGER_WRITER_DBMOD
+  );
+  assert( assert_pager_state(pPager) );
+
+  /* In order to be able to rollback, an in-memory database must journal
+  ** the page we are moving from.
+  */
+  assert( pPager->tempFile || !MEMDB );
+  if( pPager->tempFile ){
+    rc = sqlite3PagerWrite(pPg);
+    if( rc ) return rc;
+  }
+
+  /* If the page being moved is dirty and has not been saved by the latest
+  ** savepoint, then save the current contents of the page into the
+  ** sub-journal now. This is required to handle the following scenario:
+  **
+  **   BEGIN;
+  **     <journal page X, then modify it in memory>
+  **     SAVEPOINT one;
+  **       <Move page X to location Y>
+  **     ROLLBACK TO one;
+  **
+  ** If page X were not written to the sub-journal here, it would not
+  ** be possible to restore its contents when the "ROLLBACK TO one"
+  ** statement were is processed.
+  **
+  ** subjournalPage() may need to allocate space to store pPg->pgno into
+  ** one or more savepoint bitvecs. This is the reason this function
+  ** may return SQLITE_NOMEM.
+  */
+  if( (pPg->flags & PGHDR_DIRTY)!=0
+   && SQLITE_OK!=(rc = subjournalPageIfRequired(pPg))
+  ){
+    return rc;
+  }
+
+  PAGERTRACE(("MOVE %d page %d (needSync=%d) moves to %d\n",
+      PAGERID(pPager), pPg->pgno, (pPg->flags&PGHDR_NEED_SYNC)?1:0, pgno));
+  IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
+
+  /* If the journal needs to be sync()ed before page pPg->pgno can
+  ** be written to, store pPg->pgno in local variable needSyncPgno.
+  **
+  ** If the isCommit flag is set, there is no need to remember that
+  ** the journal needs to be sync()ed before database page pPg->pgno
+  ** can be written to. The caller has already promised not to write to it.
+  */
+  if( (pPg->flags&PGHDR_NEED_SYNC) && !isCommit ){
+    needSyncPgno = pPg->pgno;
+    assert( pPager->journalMode==PAGER_JOURNALMODE_OFF ||
+            pageInJournal(pPager, pPg) || pPg->pgno>pPager->dbOrigSize );
+    assert( pPg->flags&PGHDR_DIRTY );
+  }
+
+  /* If the cache contains a page with page-number pgno, remove it
+  ** from its hash chain. Also, if the PGHDR_NEED_SYNC flag was set for
+  ** page pgno before the 'move' operation, it needs to be retained
+  ** for the page moved there.
+  */
+  pPg->flags &= ~PGHDR_NEED_SYNC;
+  pPgOld = sqlite3PagerLookup(pPager, pgno);
+  assert( !pPgOld || pPgOld->nRef==1 || CORRUPT_DB );
+  if( pPgOld ){
+    if( NEVER(pPgOld->nRef>1) ){
+      sqlite3PagerUnrefNotNull(pPgOld);
+      return SQLITE_CORRUPT_BKPT;
+    }
+    pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
+    if( pPager->tempFile ){
+      /* Do not discard pages from an in-memory database since we might
+      ** need to rollback later.  Just move the page out of the way. */
+      sqlite3PcacheMove(pPgOld, pPager->dbSize+1);
+    }else{
+      sqlite3PcacheDrop(pPgOld);
+    }
+  }
+
+  origPgno = pPg->pgno;
+  sqlite3PcacheMove(pPg, pgno);
+  sqlite3PcacheMakeDirty(pPg);
+
+  /* For an in-memory database, make sure the original page continues
+  ** to exist, in case the transaction needs to roll back.  Use pPgOld
+  ** as the original page since it has already been allocated.
+  */
+  if( pPager->tempFile && pPgOld ){
+    sqlite3PcacheMove(pPgOld, origPgno);
+    sqlite3PagerUnrefNotNull(pPgOld);
+  }
+
+  if( needSyncPgno ){
+    /* If needSyncPgno is non-zero, then the journal file needs to be
+    ** sync()ed before any data is written to database file page needSyncPgno.
+    ** Currently, no such page exists in the page-cache and the
+    ** "is journaled" bitvec flag has been set. This needs to be remedied by
+    ** loading the page into the pager-cache and setting the PGHDR_NEED_SYNC
+    ** flag.
+    **
+    ** If the attempt to load the page into the page-cache fails, (due
+    ** to a malloc() or IO failure), clear the bit in the pInJournal[]
+    ** array. Otherwise, if the page is loaded and written again in
+    ** this transaction, it may be written to the database file before
+    ** it is synced into the journal file. This way, it may end up in
+    ** the journal file twice, but that is not a problem.
+    */
+    PgHdr *pPgHdr;
+    rc = sqlite3PagerGet(pPager, needSyncPgno, &pPgHdr, 0);
+    if( rc!=SQLITE_OK ){
+      if( needSyncPgno<=pPager->dbOrigSize ){
+        assert( pPager->pTmpSpace!=0 );
+        sqlite3BitvecClear(pPager->pInJournal, needSyncPgno, pPager->pTmpSpace);
+      }
+      return rc;
+    }
+    pPgHdr->flags |= PGHDR_NEED_SYNC;
+    sqlite3PcacheMakeDirty(pPgHdr);
+    sqlite3PagerUnrefNotNull(pPgHdr);
+  }
+
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** The page handle passed as the first argument refers to a dirty page
+** with a page number other than iNew. This function changes the page's
+** page number to iNew and sets the value of the PgHdr.flags field to
+** the value passed as the third parameter.
+*/
+SQLITE_PRIVATE void sqlite3PagerRekey(DbPage *pPg, Pgno iNew, u16 flags){
+  assert( pPg->pgno!=iNew );
+  pPg->flags = flags;
+  sqlite3PcacheMove(pPg, iNew);
+}
+
+/*
+** Return a pointer to the data for the specified page.
+*/
+SQLITE_PRIVATE void *sqlite3PagerGetData(DbPage *pPg){
+  assert( pPg->nRef>0 || pPg->pPager->memDb );
+  return pPg->pData;
+}
+
+/*
+** Return a pointer to the Pager.nExtra bytes of "extra" space
+** allocated along with the specified page.
+*/
+SQLITE_PRIVATE void *sqlite3PagerGetExtra(DbPage *pPg){
+  return pPg->pExtra;
+}
+
+/*
+** Get/set the locking-mode for this pager. Parameter eMode must be one
+** of PAGER_LOCKINGMODE_QUERY, PAGER_LOCKINGMODE_NORMAL or
+** PAGER_LOCKINGMODE_EXCLUSIVE. If the parameter is not _QUERY, then
+** the locking-mode is set to the value specified.
+**
+** The returned value is either PAGER_LOCKINGMODE_NORMAL or
+** PAGER_LOCKINGMODE_EXCLUSIVE, indicating the current (possibly updated)
+** locking-mode.
+*/
+SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *pPager, int eMode){
+  assert( eMode==PAGER_LOCKINGMODE_QUERY
+            || eMode==PAGER_LOCKINGMODE_NORMAL
+            || eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
+  assert( PAGER_LOCKINGMODE_QUERY<0 );
+  assert( PAGER_LOCKINGMODE_NORMAL>=0 && PAGER_LOCKINGMODE_EXCLUSIVE>=0 );
+  assert( pPager->exclusiveMode || 0==sqlite3WalHeapMemory(pPager->pWal) );
+  if( eMode>=0 && !pPager->tempFile && !sqlite3WalHeapMemory(pPager->pWal) ){
+    pPager->exclusiveMode = (u8)eMode;
+  }
+  return (int)pPager->exclusiveMode;
+}
+
+/*
+** Set the journal-mode for this pager. Parameter eMode must be one of:
+**
+**    PAGER_JOURNALMODE_DELETE
+**    PAGER_JOURNALMODE_TRUNCATE
+**    PAGER_JOURNALMODE_PERSIST
+**    PAGER_JOURNALMODE_OFF
+**    PAGER_JOURNALMODE_MEMORY
+**    PAGER_JOURNALMODE_WAL
+**
+** The journalmode is set to the value specified if the change is allowed.
+** The change may be disallowed for the following reasons:
+**
+**   *  An in-memory database can only have its journal_mode set to _OFF
+**      or _MEMORY.
+**
+**   *  Temporary databases cannot have _WAL journalmode.
+**
+** The returned indicate the current (possibly updated) journal-mode.
+*/
+SQLITE_PRIVATE int sqlite3PagerSetJournalMode(Pager *pPager, int eMode){
+  u8 eOld = pPager->journalMode;    /* Prior journalmode */
+
+  /* The eMode parameter is always valid */
+  assert(      eMode==PAGER_JOURNALMODE_DELETE    /* 0 */
+            || eMode==PAGER_JOURNALMODE_PERSIST   /* 1 */
+            || eMode==PAGER_JOURNALMODE_OFF       /* 2 */
+            || eMode==PAGER_JOURNALMODE_TRUNCATE  /* 3 */
+            || eMode==PAGER_JOURNALMODE_MEMORY    /* 4 */
+            || eMode==PAGER_JOURNALMODE_WAL       /* 5 */ );
+
+  /* This routine is only called from the OP_JournalMode opcode, and
+  ** the logic there will never allow a temporary file to be changed
+  ** to WAL mode.
+  */
+  assert( pPager->tempFile==0 || eMode!=PAGER_JOURNALMODE_WAL );
+
+  /* Do allow the journalmode of an in-memory database to be set to
+  ** anything other than MEMORY or OFF
+  */
+  if( MEMDB ){
+    assert( eOld==PAGER_JOURNALMODE_MEMORY || eOld==PAGER_JOURNALMODE_OFF );
+    if( eMode!=PAGER_JOURNALMODE_MEMORY && eMode!=PAGER_JOURNALMODE_OFF ){
+      eMode = eOld;
+    }
+  }
+
+  if( eMode!=eOld ){
+
+    /* Change the journal mode. */
+    assert( pPager->eState!=PAGER_ERROR );
+    pPager->journalMode = (u8)eMode;
+
+    /* When transitioning from TRUNCATE or PERSIST to any other journal
+    ** mode except WAL, unless the pager is in locking_mode=exclusive mode,
+    ** delete the journal file.
+    */
+    assert( (PAGER_JOURNALMODE_TRUNCATE & 5)==1 );
+    assert( (PAGER_JOURNALMODE_PERSIST & 5)==1 );
+    assert( (PAGER_JOURNALMODE_DELETE & 5)==0 );
+    assert( (PAGER_JOURNALMODE_MEMORY & 5)==4 );
+    assert( (PAGER_JOURNALMODE_OFF & 5)==0 );
+    assert( (PAGER_JOURNALMODE_WAL & 5)==5 );
+
+    assert( isOpen(pPager->fd) || pPager->exclusiveMode );
+    if( !pPager->exclusiveMode && (eOld & 5)==1 && (eMode & 1)==0 ){
+      /* In this case we would like to delete the journal file. If it is
+      ** not possible, then that is not a problem. Deleting the journal file
+      ** here is an optimization only.
+      **
+      ** Before deleting the journal file, obtain a RESERVED lock on the
+      ** database file. This ensures that the journal file is not deleted
+      ** while it is in use by some other client.
+      */
+      sqlite3OsClose(pPager->jfd);
+      if( pPager->eLock>=RESERVED_LOCK ){
+        sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
+      }else{
+        int rc = SQLITE_OK;
+        int state = pPager->eState;
+        assert( state==PAGER_OPEN || state==PAGER_READER );
+        if( state==PAGER_OPEN ){
+          rc = sqlite3PagerSharedLock(pPager);
+        }
+        if( pPager->eState==PAGER_READER ){
+          assert( rc==SQLITE_OK );
+          rc = pagerLockDb(pPager, RESERVED_LOCK);
+        }
+        if( rc==SQLITE_OK ){
+          sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
+        }
+        if( rc==SQLITE_OK && state==PAGER_READER ){
+          pagerUnlockDb(pPager, SHARED_LOCK);
+        }else if( state==PAGER_OPEN ){
+          pager_unlock(pPager);
+        }
+        assert( state==pPager->eState );
+      }
+    }else if( eMode==PAGER_JOURNALMODE_OFF || eMode==PAGER_JOURNALMODE_MEMORY ){
+      sqlite3OsClose(pPager->jfd);
+    }
+  }
+
+  /* Return the new journal mode */
+  return (int)pPager->journalMode;
+}
+
+/*
+** Return the current journal mode.
+*/
+SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager *pPager){
+  return (int)pPager->journalMode;
+}
+
+/*
+** Return TRUE if the pager is in a state where it is OK to change the
+** journalmode.  Journalmode changes can only happen when the database
+** is unmodified.
+*/
+SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager *pPager){
+  assert( assert_pager_state(pPager) );
+  if( pPager->eState>=PAGER_WRITER_CACHEMOD ) return 0;
+  if( NEVER(isOpen(pPager->jfd) && pPager->journalOff>0) ) return 0;
+  return 1;
+}
+
+/*
+** Get/set the size-limit used for persistent journal files.
+**
+** Setting the size limit to -1 means no limit is enforced.
+** An attempt to set a limit smaller than -1 is a no-op.
+*/
+SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *pPager, i64 iLimit){
+  if( iLimit>=-1 ){
+    pPager->journalSizeLimit = iLimit;
+    sqlite3WalLimit(pPager->pWal, iLimit);
+  }
+  return pPager->journalSizeLimit;
+}
+
+/*
+** Return a pointer to the pPager->pBackup variable. The backup module
+** in backup.c maintains the content of this variable. This module
+** uses it opaquely as an argument to sqlite3BackupRestart() and
+** sqlite3BackupUpdate() only.
+*/
+SQLITE_PRIVATE sqlite3_backup **sqlite3PagerBackupPtr(Pager *pPager){
+  return &pPager->pBackup;
+}
+
+#ifndef SQLITE_OMIT_VACUUM
+/*
+** Unless this is an in-memory or temporary database, clear the pager cache.
+*/
+SQLITE_PRIVATE void sqlite3PagerClearCache(Pager *pPager){
+  assert( MEMDB==0 || pPager->tempFile );
+  if( pPager->tempFile==0 ) pager_reset(pPager);
+}
+#endif
+
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** This function is called when the user invokes "PRAGMA wal_checkpoint",
+** "PRAGMA wal_blocking_checkpoint" or calls the sqlite3_wal_checkpoint()
+** or wal_blocking_checkpoint() API functions.
+**
+** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
+*/
+SQLITE_PRIVATE int sqlite3PagerCheckpoint(
+  Pager *pPager,                  /* Checkpoint on this pager */
+  sqlite3 *db,                    /* Db handle used to check for interrupts */
+  int eMode,                      /* Type of checkpoint */
+  int *pnLog,                     /* OUT: Final number of frames in log */
+  int *pnCkpt                     /* OUT: Final number of checkpointed frames */
+){
+  int rc = SQLITE_OK;
+  if( pPager->pWal==0 && pPager->journalMode==PAGER_JOURNALMODE_WAL ){
+    /* This only happens when a database file is zero bytes in size opened and
+    ** then "PRAGMA journal_mode=WAL" is run and then sqlite3_wal_checkpoint()
+    ** is invoked without any intervening transactions.  We need to start
+    ** a transaction to initialize pWal.  The PRAGMA table_list statement is
+    ** used for this since it starts transactions on every database file,
+    ** including all ATTACHed databases.  This seems expensive for a single
+    ** sqlite3_wal_checkpoint() call, but it happens very rarely.
+    ** https://sqlite.org/forum/forumpost/fd0f19d229156939
+    */
+    sqlite3_exec(db, "PRAGMA table_list",0,0,0);
+  }
+  if( pPager->pWal ){
+    rc = sqlite3WalCheckpoint(pPager->pWal, db, eMode,
+        (eMode==SQLITE_CHECKPOINT_PASSIVE ? 0 : pPager->xBusyHandler),
+        pPager->pBusyHandlerArg,
+        pPager->walSyncFlags, pPager->pageSize, (u8 *)pPager->pTmpSpace,
+        pnLog, pnCkpt
+    );
+  }
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3PagerWalCallback(Pager *pPager){
+  return sqlite3WalCallback(pPager->pWal);
+}
+
+/*
+** Return true if the underlying VFS for the given pager supports the
+** primitives necessary for write-ahead logging.
+*/
+SQLITE_PRIVATE int sqlite3PagerWalSupported(Pager *pPager){
+  const sqlite3_io_methods *pMethods = pPager->fd->pMethods;
+  if( pPager->noLock ) return 0;
+  return pPager->exclusiveMode || (pMethods->iVersion>=2 && pMethods->xShmMap);
+}
+
+/*
+** Attempt to take an exclusive lock on the database file. If a PENDING lock
+** is obtained instead, immediately release it.
+*/
+static int pagerExclusiveLock(Pager *pPager){
+  int rc;                         /* Return code */
+  u8 eOrigLock;                   /* Original lock */
+
+  assert( pPager->eLock>=SHARED_LOCK );
+  eOrigLock = pPager->eLock;
+  rc = pagerLockDb(pPager, EXCLUSIVE_LOCK);
+  if( rc!=SQLITE_OK ){
+    /* If the attempt to grab the exclusive lock failed, release the
+    ** pending lock that may have been obtained instead.  */
+    pagerUnlockDb(pPager, eOrigLock);
+  }
+
+  return rc;
+}
+
+/*
+** Call sqlite3WalOpen() to open the WAL handle. If the pager is in
+** exclusive-locking mode when this function is called, take an EXCLUSIVE
+** lock on the database file and use heap-memory to store the wal-index
+** in. Otherwise, use the normal shared-memory.
+*/
+static int pagerOpenWal(Pager *pPager){
+  int rc = SQLITE_OK;
+
+  assert( pPager->pWal==0 && pPager->tempFile==0 );
+  assert( pPager->eLock==SHARED_LOCK || pPager->eLock==EXCLUSIVE_LOCK );
+
+  /* If the pager is already in exclusive-mode, the WAL module will use
+  ** heap-memory for the wal-index instead of the VFS shared-memory
+  ** implementation. Take the exclusive lock now, before opening the WAL
+  ** file, to make sure this is safe.
+  */
+  if( pPager->exclusiveMode ){
+    rc = pagerExclusiveLock(pPager);
+  }
+
+  /* Open the connection to the log file. If this operation fails,
+  ** (e.g. due to malloc() failure), return an error code.
+  */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3WalOpen(pPager->pVfs,
+        pPager->fd, pPager->zWal, pPager->exclusiveMode,
+        pPager->journalSizeLimit, &pPager->pWal
+    );
+  }
+  pagerFixMaplimit(pPager);
+
+  return rc;
+}
+
+
+/*
+** The caller must be holding a SHARED lock on the database file to call
+** this function.
+**
+** If the pager passed as the first argument is open on a real database
+** file (not a temp file or an in-memory database), and the WAL file
+** is not already open, make an attempt to open it now. If successful,
+** return SQLITE_OK. If an error occurs or the VFS used by the pager does
+** not support the xShmXXX() methods, return an error code. *pbOpen is
+** not modified in either case.
+**
+** If the pager is open on a temp-file (or in-memory database), or if
+** the WAL file is already open, set *pbOpen to 1 and return SQLITE_OK
+** without doing anything.
+*/
+SQLITE_PRIVATE int sqlite3PagerOpenWal(
+  Pager *pPager,                  /* Pager object */
+  int *pbOpen                     /* OUT: Set to true if call is a no-op */
+){
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( assert_pager_state(pPager) );
+  assert( pPager->eState==PAGER_OPEN   || pbOpen );
+  assert( pPager->eState==PAGER_READER || !pbOpen );
+  assert( pbOpen==0 || *pbOpen==0 );
+  assert( pbOpen!=0 || (!pPager->tempFile && !pPager->pWal) );
+
+  if( !pPager->tempFile && !pPager->pWal ){
+    if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;
+
+    /* Close any rollback journal previously open */
+    sqlite3OsClose(pPager->jfd);
+
+    rc = pagerOpenWal(pPager);
+    if( rc==SQLITE_OK ){
+      pPager->journalMode = PAGER_JOURNALMODE_WAL;
+      pPager->eState = PAGER_OPEN;
+    }
+  }else{
+    *pbOpen = 1;
+  }
+
+  return rc;
+}
+
+/*
+** This function is called to close the connection to the log file prior
+** to switching from WAL to rollback mode.
+**
+** Before closing the log file, this function attempts to take an
+** EXCLUSIVE lock on the database file. If this cannot be obtained, an
+** error (SQLITE_BUSY) is returned and the log connection is not closed.
+** If successful, the EXCLUSIVE lock is not released before returning.
+*/
+SQLITE_PRIVATE int sqlite3PagerCloseWal(Pager *pPager, sqlite3 *db){
+  int rc = SQLITE_OK;
+
+  assert( pPager->journalMode==PAGER_JOURNALMODE_WAL );
+
+  /* If the log file is not already open, but does exist in the file-system,
+  ** it may need to be checkpointed before the connection can switch to
+  ** rollback mode. Open it now so this can happen.
+  */
+  if( !pPager->pWal ){
+    int logexists = 0;
+    rc = pagerLockDb(pPager, SHARED_LOCK);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3OsAccess(
+          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &logexists
+      );
+    }
+    if( rc==SQLITE_OK && logexists ){
+      rc = pagerOpenWal(pPager);
+    }
+  }
+
+  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
+  ** the database file, the log and log-summary files will be deleted.
+  */
+  if( rc==SQLITE_OK && pPager->pWal ){
+    rc = pagerExclusiveLock(pPager);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3WalClose(pPager->pWal, db, pPager->walSyncFlags,
+                           pPager->pageSize, (u8*)pPager->pTmpSpace);
+      pPager->pWal = 0;
+      pagerFixMaplimit(pPager);
+      if( rc && !pPager->exclusiveMode ) pagerUnlockDb(pPager, SHARED_LOCK);
+    }
+  }
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+/*
+** If pager pPager is a wal-mode database not in exclusive locking mode,
+** invoke the sqlite3WalWriteLock() function on the associated Wal object
+** with the same db and bLock parameters as were passed to this function.
+** Return an SQLite error code if an error occurs, or SQLITE_OK otherwise.
+*/
+SQLITE_PRIVATE int sqlite3PagerWalWriteLock(Pager *pPager, int bLock){
+  int rc = SQLITE_OK;
+  if( pagerUseWal(pPager) && pPager->exclusiveMode==0 ){
+    rc = sqlite3WalWriteLock(pPager->pWal, bLock);
+  }
+  return rc;
+}
+
+/*
+** Set the database handle used by the wal layer to determine if
+** blocking locks are required.
+*/
+SQLITE_PRIVATE void sqlite3PagerWalDb(Pager *pPager, sqlite3 *db){
+  if( pagerUseWal(pPager) ){
+    sqlite3WalDb(pPager->pWal, db);
+  }
+}
+#endif
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+/*
+** If this is a WAL database, obtain a snapshot handle for the snapshot
+** currently open. Otherwise, return an error.
+*/
+SQLITE_PRIVATE int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot){
+  int rc = SQLITE_ERROR;
+  if( pPager->pWal ){
+    rc = sqlite3WalSnapshotGet(pPager->pWal, ppSnapshot);
+  }
+  return rc;
+}
+
+/*
+** If this is a WAL database, store a pointer to pSnapshot. Next time a
+** read transaction is opened, attempt to read from the snapshot it
+** identifies. If this is not a WAL database, return an error.
+*/
+SQLITE_PRIVATE int sqlite3PagerSnapshotOpen(
+  Pager *pPager,
+  sqlite3_snapshot *pSnapshot
+){
+  int rc = SQLITE_OK;
+  if( pPager->pWal ){
+    sqlite3WalSnapshotOpen(pPager->pWal, pSnapshot);
+  }else{
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** If this is a WAL database, call sqlite3WalSnapshotRecover(). If this
+** is not a WAL database, return an error.
+*/
+SQLITE_PRIVATE int sqlite3PagerSnapshotRecover(Pager *pPager){
+  int rc;
+  if( pPager->pWal ){
+    rc = sqlite3WalSnapshotRecover(pPager->pWal);
+  }else{
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** The caller currently has a read transaction open on the database.
+** If this is not a WAL database, SQLITE_ERROR is returned. Otherwise,
+** this function takes a SHARED lock on the CHECKPOINTER slot and then
+** checks if the snapshot passed as the second argument is still
+** available. If so, SQLITE_OK is returned.
+**
+** If the snapshot is not available, SQLITE_ERROR is returned. Or, if
+** the CHECKPOINTER lock cannot be obtained, SQLITE_BUSY. If any error
+** occurs (any value other than SQLITE_OK is returned), the CHECKPOINTER
+** lock is released before returning.
+*/
+SQLITE_PRIVATE int sqlite3PagerSnapshotCheck(Pager *pPager, sqlite3_snapshot *pSnapshot){
+  int rc;
+  if( pPager->pWal ){
+    rc = sqlite3WalSnapshotCheck(pPager->pWal, pSnapshot);
+  }else{
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** Release a lock obtained by an earlier successful call to
+** sqlite3PagerSnapshotCheck().
+*/
+SQLITE_PRIVATE void sqlite3PagerSnapshotUnlock(Pager *pPager){
+  assert( pPager->pWal );
+  sqlite3WalSnapshotUnlock(pPager->pWal);
+}
+
+#endif /* SQLITE_ENABLE_SNAPSHOT */
+#endif /* !SQLITE_OMIT_WAL */
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/*
+** A read-lock must be held on the pager when this function is called. If
+** the pager is in WAL mode and the WAL file currently contains one or more
+** frames, return the size in bytes of the page images stored within the
+** WAL frames. Otherwise, if this is not a WAL database or the WAL file
+** is empty, return 0.
+*/
+SQLITE_PRIVATE int sqlite3PagerWalFramesize(Pager *pPager){
+  assert( pPager->eState>=PAGER_READER );
+  return sqlite3WalFramesize(pPager->pWal);
+}
+#endif
+
+#if defined(SQLITE_USE_SEH) && !defined(SQLITE_OMIT_WAL)
+SQLITE_PRIVATE int sqlite3PagerWalSystemErrno(Pager *pPager){
+  return sqlite3WalSystemErrno(pPager->pWal);
+}
+#endif
+
+#endif /* SQLITE_OMIT_DISKIO */
+
+/************** End of pager.c ***********************************************/
+/************** Begin file wal.c *********************************************/
+/*
+** 2010 February 1
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the implementation of a write-ahead log (WAL) used in
+** "journal_mode=WAL" mode.
+**
+** WRITE-AHEAD LOG (WAL) FILE FORMAT
+**
+** A WAL file consists of a header followed by zero or more "frames".
+** Each frame records the revised content of a single page from the
+** database file.  All changes to the database are recorded by writing
+** frames into the WAL.  Transactions commit when a frame is written that
+** contains a commit marker.  A single WAL can and usually does record
+** multiple transactions.  Periodically, the content of the WAL is
+** transferred back into the database file in an operation called a
+** "checkpoint".
+**
+** A single WAL file can be used multiple times.  In other words, the
+** WAL can fill up with frames and then be checkpointed and then new
+** frames can overwrite the old ones.  A WAL always grows from beginning
+** toward the end.  Checksums and counters attached to each frame are
+** used to determine which frames within the WAL are valid and which
+** are leftovers from prior checkpoints.
+**
+** The WAL header is 32 bytes in size and consists of the following eight
+** big-endian 32-bit unsigned integer values:
+**
+**     0: Magic number.  0x377f0682 or 0x377f0683
+**     4: File format version.  Currently 3007000
+**     8: Database page size.  Example: 1024
+**    12: Checkpoint sequence number
+**    16: Salt-1, random integer incremented with each checkpoint
+**    20: Salt-2, a different random integer changing with each ckpt
+**    24: Checksum-1 (first part of checksum for first 24 bytes of header).
+**    28: Checksum-2 (second part of checksum for first 24 bytes of header).
+**
+** Immediately following the wal-header are zero or more frames. Each
+** frame consists of a 24-byte frame-header followed by <page-size> bytes
+** of page data. The frame-header is six big-endian 32-bit unsigned
+** integer values, as follows:
+**
+**     0: Page number.
+**     4: For commit records, the size of the database image in pages
+**        after the commit. For all other records, zero.
+**     8: Salt-1 (copied from the header)
+**    12: Salt-2 (copied from the header)
+**    16: Checksum-1.
+**    20: Checksum-2.
+**
+** A frame is considered valid if and only if the following conditions are
+** true:
+**
+**    (1) The salt-1 and salt-2 values in the frame-header match
+**        salt values in the wal-header
+**
+**    (2) The checksum values in the final 8 bytes of the frame-header
+**        exactly match the checksum computed consecutively on the
+**        WAL header and the first 8 bytes and the content of all frames
+**        up to and including the current frame.
+**
+** The checksum is computed using 32-bit big-endian integers if the
+** magic number in the first 4 bytes of the WAL is 0x377f0683 and it
+** is computed using little-endian if the magic number is 0x377f0682.
+** The checksum values are always stored in the frame header in a
+** big-endian format regardless of which byte order is used to compute
+** the checksum.  The checksum is computed by interpreting the input as
+** an even number of unsigned 32-bit integers: x[0] through x[N].  The
+** algorithm used for the checksum is as follows:
+**
+**   for i from 0 to n-1 step 2:
+**     s0 += x[i] + s1;
+**     s1 += x[i+1] + s0;
+**   endfor
+**
+** Note that s0 and s1 are both weighted checksums using fibonacci weights
+** in reverse order (the largest fibonacci weight occurs on the first element
+** of the sequence being summed.)  The s1 value spans all 32-bit
+** terms of the sequence whereas s0 omits the final term.
+**
+** On a checkpoint, the WAL is first VFS.xSync-ed, then valid content of the
+** WAL is transferred into the database, then the database is VFS.xSync-ed.
+** The VFS.xSync operations serve as write barriers - all writes launched
+** before the xSync must complete before any write that launches after the
+** xSync begins.
+**
+** After each checkpoint, the salt-1 value is incremented and the salt-2
+** value is randomized.  This prevents old and new frames in the WAL from
+** being considered valid at the same time and being checkpointing together
+** following a crash.
+**
+** READER ALGORITHM
+**
+** To read a page from the database (call it page number P), a reader
+** first checks the WAL to see if it contains page P.  If so, then the
+** last valid instance of page P that is a followed by a commit frame
+** or is a commit frame itself becomes the value read.  If the WAL
+** contains no copies of page P that are valid and which are a commit
+** frame or are followed by a commit frame, then page P is read from
+** the database file.
+**
+** To start a read transaction, the reader records the index of the last
+** valid frame in the WAL.  The reader uses this recorded "mxFrame" value
+** for all subsequent read operations.  New transactions can be appended
+** to the WAL, but as long as the reader uses its original mxFrame value
+** and ignores the newly appended content, it will see a consistent snapshot
+** of the database from a single point in time.  This technique allows
+** multiple concurrent readers to view different versions of the database
+** content simultaneously.
+**
+** The reader algorithm in the previous paragraphs works correctly, but
+** because frames for page P can appear anywhere within the WAL, the
+** reader has to scan the entire WAL looking for page P frames.  If the
+** WAL is large (multiple megabytes is typical) that scan can be slow,
+** and read performance suffers.  To overcome this problem, a separate
+** data structure called the wal-index is maintained to expedite the
+** search for frames of a particular page.
+**
+** WAL-INDEX FORMAT
+**
+** Conceptually, the wal-index is shared memory, though VFS implementations
+** might choose to implement the wal-index using a mmapped file.  Because
+** the wal-index is shared memory, SQLite does not support journal_mode=WAL
+** on a network filesystem.  All users of the database must be able to
+** share memory.
+**
+** In the default unix and windows implementation, the wal-index is a mmapped
+** file whose name is the database name with a "-shm" suffix added.  For that
+** reason, the wal-index is sometimes called the "shm" file.
+**
+** The wal-index is transient.  After a crash, the wal-index can (and should
+** be) reconstructed from the original WAL file.  In fact, the VFS is required
+** to either truncate or zero the header of the wal-index when the last
+** connection to it closes.  Because the wal-index is transient, it can
+** use an architecture-specific format; it does not have to be cross-platform.
+** Hence, unlike the database and WAL file formats which store all values
+** as big endian, the wal-index can store multi-byte values in the native
+** byte order of the host computer.
+**
+** The purpose of the wal-index is to answer this question quickly:  Given
+** a page number P and a maximum frame index M, return the index of the
+** last frame in the wal before frame M for page P in the WAL, or return
+** NULL if there are no frames for page P in the WAL prior to M.
+**
+** The wal-index consists of a header region, followed by an one or
+** more index blocks.
+**
+** The wal-index header contains the total number of frames within the WAL
+** in the mxFrame field.
+**
+** Each index block except for the first contains information on
+** HASHTABLE_NPAGE frames. The first index block contains information on
+** HASHTABLE_NPAGE_ONE frames. The values of HASHTABLE_NPAGE_ONE and
+** HASHTABLE_NPAGE are selected so that together the wal-index header and
+** first index block are the same size as all other index blocks in the
+** wal-index.  The values are:
+**
+**   HASHTABLE_NPAGE      4096
+**   HASHTABLE_NPAGE_ONE  4062
+**
+** Each index block contains two sections, a page-mapping that contains the
+** database page number associated with each wal frame, and a hash-table
+** that allows readers to query an index block for a specific page number.
+** The page-mapping is an array of HASHTABLE_NPAGE (or HASHTABLE_NPAGE_ONE
+** for the first index block) 32-bit page numbers. The first entry in the
+** first index-block contains the database page number corresponding to the
+** first frame in the WAL file. The first entry in the second index block
+** in the WAL file corresponds to the (HASHTABLE_NPAGE_ONE+1)th frame in
+** the log, and so on.
+**
+** The last index block in a wal-index usually contains less than the full
+** complement of HASHTABLE_NPAGE (or HASHTABLE_NPAGE_ONE) page-numbers,
+** depending on the contents of the WAL file. This does not change the
+** allocated size of the page-mapping array - the page-mapping array merely
+** contains unused entries.
+**
+** Even without using the hash table, the last frame for page P
+** can be found by scanning the page-mapping sections of each index block
+** starting with the last index block and moving toward the first, and
+** within each index block, starting at the end and moving toward the
+** beginning.  The first entry that equals P corresponds to the frame
+** holding the content for that page.
+**
+** The hash table consists of HASHTABLE_NSLOT 16-bit unsigned integers.
+** HASHTABLE_NSLOT = 2*HASHTABLE_NPAGE, and there is one entry in the
+** hash table for each page number in the mapping section, so the hash
+** table is never more than half full.  The expected number of collisions
+** prior to finding a match is 1.  Each entry of the hash table is an
+** 1-based index of an entry in the mapping section of the same
+** index block.   Let K be the 1-based index of the largest entry in
+** the mapping section.  (For index blocks other than the last, K will
+** always be exactly HASHTABLE_NPAGE (4096) and for the last index block
+** K will be (mxFrame%HASHTABLE_NPAGE).)  Unused slots of the hash table
+** contain a value of 0.
+**
+** To look for page P in the hash table, first compute a hash iKey on
+** P as follows:
+**
+**      iKey = (P * 383) % HASHTABLE_NSLOT
+**
+** Then start scanning entries of the hash table, starting with iKey
+** (wrapping around to the beginning when the end of the hash table is
+** reached) until an unused hash slot is found. Let the first unused slot
+** be at index iUnused.  (iUnused might be less than iKey if there was
+** wrap-around.) Because the hash table is never more than half full,
+** the search is guaranteed to eventually hit an unused entry.  Let
+** iMax be the value between iKey and iUnused, closest to iUnused,
+** where aHash[iMax]==P.  If there is no iMax entry (if there exists
+** no hash slot such that aHash[i]==p) then page P is not in the
+** current index block.  Otherwise the iMax-th mapping entry of the
+** current index block corresponds to the last entry that references
+** page P.
+**
+** A hash search begins with the last index block and moves toward the
+** first index block, looking for entries corresponding to page P.  On
+** average, only two or three slots in each index block need to be
+** examined in order to either find the last entry for page P, or to
+** establish that no such entry exists in the block.  Each index block
+** holds over 4000 entries.  So two or three index blocks are sufficient
+** to cover a typical 10 megabyte WAL file, assuming 1K pages.  8 or 10
+** comparisons (on average) suffice to either locate a frame in the
+** WAL or to establish that the frame does not exist in the WAL.  This
+** is much faster than scanning the entire 10MB WAL.
+**
+** Note that entries are added in order of increasing K.  Hence, one
+** reader might be using some value K0 and a second reader that started
+** at a later time (after additional transactions were added to the WAL
+** and to the wal-index) might be using a different value K1, where K1>K0.
+** Both readers can use the same hash table and mapping section to get
+** the correct result.  There may be entries in the hash table with
+** K>K0 but to the first reader, those entries will appear to be unused
+** slots in the hash table and so the first reader will get an answer as
+** if no values greater than K0 had ever been inserted into the hash table
+** in the first place - which is what reader one wants.  Meanwhile, the
+** second reader using K1 will see additional values that were inserted
+** later, which is exactly what reader two wants.
+**
+** When a rollback occurs, the value of K is decreased. Hash table entries
+** that correspond to frames greater than the new K value are removed
+** from the hash table at this point.
+*/
+#ifndef SQLITE_OMIT_WAL
+
+/* #include "wal.h" */
+
+/*
+** Trace output macros
+*/
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+SQLITE_PRIVATE int sqlite3WalTrace = 0;
+# define WALTRACE(X)  if(sqlite3WalTrace) sqlite3DebugPrintf X
+#else
+# define WALTRACE(X)
+#endif
+
+/*
+** The maximum (and only) versions of the wal and wal-index formats
+** that may be interpreted by this version of SQLite.
+**
+** If a client begins recovering a WAL file and finds that (a) the checksum
+** values in the wal-header are correct and (b) the version field is not
+** WAL_MAX_VERSION, recovery fails and SQLite returns SQLITE_CANTOPEN.
+**
+** Similarly, if a client successfully reads a wal-index header (i.e. the
+** checksum test is successful) and finds that the version field is not
+** WALINDEX_MAX_VERSION, then no read-transaction is opened and SQLite
+** returns SQLITE_CANTOPEN.
+*/
+#define WAL_MAX_VERSION      3007000
+#define WALINDEX_MAX_VERSION 3007000
+
+/*
+** Index numbers for various locking bytes.   WAL_NREADER is the number
+** of available reader locks and should be at least 3.  The default
+** is SQLITE_SHM_NLOCK==8 and  WAL_NREADER==5.
+**
+** Technically, the various VFSes are free to implement these locks however
+** they see fit.  However, compatibility is encouraged so that VFSes can
+** interoperate.  The standard implementation used on both unix and windows
+** is for the index number to indicate a byte offset into the
+** WalCkptInfo.aLock[] array in the wal-index header.  In other words, all
+** locks are on the shm file.  The WALINDEX_LOCK_OFFSET constant (which
+** should be 120) is the location in the shm file for the first locking
+** byte.
+*/
+#define WAL_WRITE_LOCK         0
+#define WAL_ALL_BUT_WRITE      1
+#define WAL_CKPT_LOCK          1
+#define WAL_RECOVER_LOCK       2
+#define WAL_READ_LOCK(I)       (3+(I))
+#define WAL_NREADER            (SQLITE_SHM_NLOCK-3)
+
+
+/* Object declarations */
+typedef struct WalIndexHdr WalIndexHdr;
+typedef struct WalIterator WalIterator;
+typedef struct WalCkptInfo WalCkptInfo;
+
+
+/*
+** The following object holds a copy of the wal-index header content.
+**
+** The actual header in the wal-index consists of two copies of this
+** object followed by one instance of the WalCkptInfo object.
+** For all versions of SQLite through 3.10.0 and probably beyond,
+** the locking bytes (WalCkptInfo.aLock) start at offset 120 and
+** the total header size is 136 bytes.
+**
+** The szPage value can be any power of 2 between 512 and 32768, inclusive.
+** Or it can be 1 to represent a 65536-byte page.  The latter case was
+** added in 3.7.1 when support for 64K pages was added.
+*/
+struct WalIndexHdr {
+  u32 iVersion;                   /* Wal-index version */
+  u32 unused;                     /* Unused (padding) field */
+  u32 iChange;                    /* Counter incremented each transaction */
+  u8 isInit;                      /* 1 when initialized */
+  u8 bigEndCksum;                 /* True if checksums in WAL are big-endian */
+  u16 szPage;                     /* Database page size in bytes. 1==64K */
+  u32 mxFrame;                    /* Index of last valid frame in the WAL */
+  u32 nPage;                      /* Size of database in pages */
+  u32 aFrameCksum[2];             /* Checksum of last frame in log */
+  u32 aSalt[2];                   /* Two salt values copied from WAL header */
+  u32 aCksum[2];                  /* Checksum over all prior fields */
+};
+
+/*
+** A copy of the following object occurs in the wal-index immediately
+** following the second copy of the WalIndexHdr.  This object stores
+** information used by checkpoint.
+**
+** nBackfill is the number of frames in the WAL that have been written
+** back into the database. (We call the act of moving content from WAL to
+** database "backfilling".)  The nBackfill number is never greater than
+** WalIndexHdr.mxFrame.  nBackfill can only be increased by threads
+** holding the WAL_CKPT_LOCK lock (which includes a recovery thread).
+** However, a WAL_WRITE_LOCK thread can move the value of nBackfill from
+** mxFrame back to zero when the WAL is reset.
+**
+** nBackfillAttempted is the largest value of nBackfill that a checkpoint
+** has attempted to achieve.  Normally nBackfill==nBackfillAtempted, however
+** the nBackfillAttempted is set before any backfilling is done and the
+** nBackfill is only set after all backfilling completes.  So if a checkpoint
+** crashes, nBackfillAttempted might be larger than nBackfill.  The
+** WalIndexHdr.mxFrame must never be less than nBackfillAttempted.
+**
+** The aLock[] field is a set of bytes used for locking.  These bytes should
+** never be read or written.
+**
+** There is one entry in aReadMark[] for each reader lock.  If a reader
+** holds read-lock K, then the value in aReadMark[K] is no greater than
+** the mxFrame for that reader.  The value READMARK_NOT_USED (0xffffffff)
+** for any aReadMark[] means that entry is unused.  aReadMark[0] is
+** a special case; its value is never used and it exists as a place-holder
+** to avoid having to offset aReadMark[] indexes by one.  Readers holding
+** WAL_READ_LOCK(0) always ignore the entire WAL and read all content
+** directly from the database.
+**
+** The value of aReadMark[K] may only be changed by a thread that
+** is holding an exclusive lock on WAL_READ_LOCK(K).  Thus, the value of
+** aReadMark[K] cannot changed while there is a reader is using that mark
+** since the reader will be holding a shared lock on WAL_READ_LOCK(K).
+**
+** The checkpointer may only transfer frames from WAL to database where
+** the frame numbers are less than or equal to every aReadMark[] that is
+** in use (that is, every aReadMark[j] for which there is a corresponding
+** WAL_READ_LOCK(j)).  New readers (usually) pick the aReadMark[] with the
+** largest value and will increase an unused aReadMark[] to mxFrame if there
+** is not already an aReadMark[] equal to mxFrame.  The exception to the
+** previous sentence is when nBackfill equals mxFrame (meaning that everything
+** in the WAL has been backfilled into the database) then new readers
+** will choose aReadMark[0] which has value 0 and hence such reader will
+** get all their all content directly from the database file and ignore
+** the WAL.
+**
+** Writers normally append new frames to the end of the WAL.  However,
+** if nBackfill equals mxFrame (meaning that all WAL content has been
+** written back into the database) and if no readers are using the WAL
+** (in other words, if there are no WAL_READ_LOCK(i) where i>0) then
+** the writer will first "reset" the WAL back to the beginning and start
+** writing new content beginning at frame 1.
+**
+** We assume that 32-bit loads are atomic and so no locks are needed in
+** order to read from any aReadMark[] entries.
+*/
+struct WalCkptInfo {
+  u32 nBackfill;                  /* Number of WAL frames backfilled into DB */
+  u32 aReadMark[WAL_NREADER];     /* Reader marks */
+  u8 aLock[SQLITE_SHM_NLOCK];     /* Reserved space for locks */
+  u32 nBackfillAttempted;         /* WAL frames perhaps written, or maybe not */
+  u32 notUsed0;                   /* Available for future enhancements */
+};
+#define READMARK_NOT_USED  0xffffffff
+
+/*
+** This is a schematic view of the complete 136-byte header of the
+** wal-index file (also known as the -shm file):
+**
+**      +-----------------------------+
+**   0: | iVersion                    | \
+**      +-----------------------------+  |
+**   4: | (unused padding)            |  |
+**      +-----------------------------+  |
+**   8: | iChange                     |  |
+**      +-------+-------+-------------+  |
+**  12: | bInit |  bBig |   szPage    |  |
+**      +-------+-------+-------------+  |
+**  16: | mxFrame                     |  |  First copy of the
+**      +-----------------------------+  |  WalIndexHdr object
+**  20: | nPage                       |  |
+**      +-----------------------------+  |
+**  24: | aFrameCksum                 |  |
+**      |                             |  |
+**      +-----------------------------+  |
+**  32: | aSalt                       |  |
+**      |                             |  |
+**      +-----------------------------+  |
+**  40: | aCksum                      |  |
+**      |                             | /
+**      +-----------------------------+
+**  48: | iVersion                    | \
+**      +-----------------------------+  |
+**  52: | (unused padding)            |  |
+**      +-----------------------------+  |
+**  56: | iChange                     |  |
+**      +-------+-------+-------------+  |
+**  60: | bInit |  bBig |   szPage    |  |
+**      +-------+-------+-------------+  |  Second copy of the
+**  64: | mxFrame                     |  |  WalIndexHdr
+**      +-----------------------------+  |
+**  68: | nPage                       |  |
+**      +-----------------------------+  |
+**  72: | aFrameCksum                 |  |
+**      |                             |  |
+**      +-----------------------------+  |
+**  80: | aSalt                       |  |
+**      |                             |  |
+**      +-----------------------------+  |
+**  88: | aCksum                      |  |
+**      |                             | /
+**      +-----------------------------+
+**  96: | nBackfill                   |
+**      +-----------------------------+
+** 100: | 5 read marks                |
+**      |                             |
+**      |                             |
+**      |                             |
+**      |                             |
+**      +-------+-------+------+------+
+** 120: | Write | Ckpt  | Rcvr | Rd0  | \
+**      +-------+-------+------+------+  ) 8 lock bytes
+**      | Read1 | Read2 | Rd3  | Rd4  | /
+**      +-------+-------+------+------+
+** 128: | nBackfillAttempted          |
+**      +-----------------------------+
+** 132: | (unused padding)            |
+**      +-----------------------------+
+*/
+
+/* A block of WALINDEX_LOCK_RESERVED bytes beginning at
+** WALINDEX_LOCK_OFFSET is reserved for locks. Since some systems
+** only support mandatory file-locks, we do not read or write data
+** from the region of the file on which locks are applied.
+*/
+#define WALINDEX_LOCK_OFFSET (sizeof(WalIndexHdr)*2+offsetof(WalCkptInfo,aLock))
+#define WALINDEX_HDR_SIZE    (sizeof(WalIndexHdr)*2+sizeof(WalCkptInfo))
+
+/* Size of header before each frame in wal */
+#define WAL_FRAME_HDRSIZE 24
+
+/* Size of write ahead log header, including checksum. */
+#define WAL_HDRSIZE 32
+
+/* WAL magic value. Either this value, or the same value with the least
+** significant bit also set (WAL_MAGIC | 0x00000001) is stored in 32-bit
+** big-endian format in the first 4 bytes of a WAL file.
+**
+** If the LSB is set, then the checksums for each frame within the WAL
+** file are calculated by treating all data as an array of 32-bit
+** big-endian words. Otherwise, they are calculated by interpreting
+** all data as 32-bit little-endian words.
+*/
+#define WAL_MAGIC 0x377f0682
+
+/*
+** Return the offset of frame iFrame in the write-ahead log file,
+** assuming a database page size of szPage bytes. The offset returned
+** is to the start of the write-ahead log frame-header.
+*/
+#define walFrameOffset(iFrame, szPage) (                               \
+  WAL_HDRSIZE + ((iFrame)-1)*(i64)((szPage)+WAL_FRAME_HDRSIZE)         \
+)
+
+/*
+** An open write-ahead log file is represented by an instance of the
+** following object.
+*/
+struct Wal {
+  sqlite3_vfs *pVfs;         /* The VFS used to create pDbFd */
+  sqlite3_file *pDbFd;       /* File handle for the database file */
+  sqlite3_file *pWalFd;      /* File handle for WAL file */
+  u32 iCallback;             /* Value to pass to log callback (or 0) */
+  i64 mxWalSize;             /* Truncate WAL to this size upon reset */
+  int nWiData;               /* Size of array apWiData */
+  int szFirstBlock;          /* Size of first block written to WAL file */
+  volatile u32 **apWiData;   /* Pointer to wal-index content in memory */
+  u32 szPage;                /* Database page size */
+  i16 readLock;              /* Which read lock is being held.  -1 for none */
+  u8 syncFlags;              /* Flags to use to sync header writes */
+  u8 exclusiveMode;          /* Non-zero if connection is in exclusive mode */
+  u8 writeLock;              /* True if in a write transaction */
+  u8 ckptLock;               /* True if holding a checkpoint lock */
+  u8 readOnly;               /* WAL_RDWR, WAL_RDONLY, or WAL_SHM_RDONLY */
+  u8 truncateOnCommit;       /* True to truncate WAL file on commit */
+  u8 syncHeader;             /* Fsync the WAL header if true */
+  u8 padToSectorBoundary;    /* Pad transactions out to the next sector */
+  u8 bShmUnreliable;         /* SHM content is read-only and unreliable */
+  WalIndexHdr hdr;           /* Wal-index header for current transaction */
+  u32 minFrame;              /* Ignore wal frames before this one */
+  u32 iReCksum;              /* On commit, recalculate checksums from here */
+  const char *zWalName;      /* Name of WAL file */
+  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
+#ifdef SQLITE_USE_SEH
+  u32 lockMask;              /* Mask of locks held */
+  void *pFree;               /* Pointer to sqlite3_free() if exception thrown */
+  u32 *pWiValue;             /* Value to write into apWiData[iWiPg] */
+  int iWiPg;                 /* Write pWiValue into apWiData[iWiPg] */
+  int iSysErrno;             /* System error code following exception */
+#endif
+#ifdef SQLITE_DEBUG
+  int nSehTry;               /* Number of nested SEH_TRY{} blocks */
+  u8 lockError;              /* True if a locking error has occurred */
+#endif
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  WalIndexHdr *pSnapshot;    /* Start transaction here if not NULL */
+  int bGetSnapshot;          /* Transaction opened for sqlite3_get_snapshot() */
+#endif
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  sqlite3 *db;
+#endif
+};
+
+/*
+** Candidate values for Wal.exclusiveMode.
+*/
+#define WAL_NORMAL_MODE     0
+#define WAL_EXCLUSIVE_MODE  1
+#define WAL_HEAPMEMORY_MODE 2
+
+/*
+** Possible values for WAL.readOnly
+*/
+#define WAL_RDWR        0    /* Normal read/write connection */
+#define WAL_RDONLY      1    /* The WAL file is readonly */
+#define WAL_SHM_RDONLY  2    /* The SHM file is readonly */
+
+/*
+** Each page of the wal-index mapping contains a hash-table made up of
+** an array of HASHTABLE_NSLOT elements of the following type.
+*/
+typedef u16 ht_slot;
+
+/*
+** This structure is used to implement an iterator that loops through
+** all frames in the WAL in database page order. Where two or more frames
+** correspond to the same database page, the iterator visits only the
+** frame most recently written to the WAL (in other words, the frame with
+** the largest index).
+**
+** The internals of this structure are only accessed by:
+**
+**   walIteratorInit() - Create a new iterator,
+**   walIteratorNext() - Step an iterator,
+**   walIteratorFree() - Free an iterator.
+**
+** This functionality is used by the checkpoint code (see walCheckpoint()).
+*/
+struct WalIterator {
+  u32 iPrior;                     /* Last result returned from the iterator */
+  int nSegment;                   /* Number of entries in aSegment[] */
+  struct WalSegment {
+    int iNext;                    /* Next slot in aIndex[] not yet returned */
+    ht_slot *aIndex;              /* i0, i1, i2... such that aPgno[iN] ascend */
+    u32 *aPgno;                   /* Array of page numbers. */
+    int nEntry;                   /* Nr. of entries in aPgno[] and aIndex[] */
+    int iZero;                    /* Frame number associated with aPgno[0] */
+  } aSegment[1];                  /* One for every 32KB page in the wal-index */
+};
+
+/*
+** Define the parameters of the hash tables in the wal-index file. There
+** is a hash-table following every HASHTABLE_NPAGE page numbers in the
+** wal-index.
+**
+** Changing any of these constants will alter the wal-index format and
+** create incompatibilities.
+*/
+#define HASHTABLE_NPAGE      4096                 /* Must be power of 2 */
+#define HASHTABLE_HASH_1     383                  /* Should be prime */
+#define HASHTABLE_NSLOT      (HASHTABLE_NPAGE*2)  /* Must be a power of 2 */
+
+/*
+** The block of page numbers associated with the first hash-table in a
+** wal-index is smaller than usual. This is so that there is a complete
+** hash-table on each aligned 32KB page of the wal-index.
+*/
+#define HASHTABLE_NPAGE_ONE  (HASHTABLE_NPAGE - (WALINDEX_HDR_SIZE/sizeof(u32)))
+
+/* The wal-index is divided into pages of WALINDEX_PGSZ bytes each. */
+#define WALINDEX_PGSZ   (                                         \
+    sizeof(ht_slot)*HASHTABLE_NSLOT + HASHTABLE_NPAGE*sizeof(u32) \
+)
+
+/*
+** Structured Exception Handling (SEH) is a Windows-specific technique
+** for catching exceptions raised while accessing memory-mapped files.
+**
+** The -DSQLITE_USE_SEH compile-time option means to use SEH to catch and
+** deal with system-level errors that arise during WAL -shm file processing.
+** Without this compile-time option, any system-level faults that appear
+** while accessing the memory-mapped -shm file will cause a process-wide
+** signal to be deliver, which will more than likely cause the entire
+** process to exit.
+*/
+#ifdef SQLITE_USE_SEH
+#include <Windows.h>
+
+/* Beginning of a block of code in which an exception might occur */
+# define SEH_TRY    __try { \
+   assert( walAssertLockmask(pWal) && pWal->nSehTry==0 ); \
+   VVA_ONLY(pWal->nSehTry++);
+
+/* The end of a block of code in which an exception might occur */
+# define SEH_EXCEPT(X) \
+   VVA_ONLY(pWal->nSehTry--); \
+   assert( pWal->nSehTry==0 ); \
+   } __except( sehExceptionFilter(pWal, GetExceptionCode(), GetExceptionInformation() ) ){ X }
+
+/* Simulate a memory-mapping fault in the -shm file for testing purposes */
+# define SEH_INJECT_FAULT sehInjectFault(pWal)
+
+/*
+** The second argument is the return value of GetExceptionCode() for the
+** current exception. Return EXCEPTION_EXECUTE_HANDLER if the exception code
+** indicates that the exception may have been caused by accessing the *-shm
+** file mapping. Or EXCEPTION_CONTINUE_SEARCH otherwise.
+*/
+static int sehExceptionFilter(Wal *pWal, int eCode, EXCEPTION_POINTERS *p){
+  VVA_ONLY(pWal->nSehTry--);
+  if( eCode==EXCEPTION_IN_PAGE_ERROR ){
+    if( p && p->ExceptionRecord && p->ExceptionRecord->NumberParameters>=3 ){
+      /* From MSDN: For this type of exception, the first element of the
+      ** ExceptionInformation[] array is a read-write flag - 0 if the exception
+      ** was thrown while reading, 1 if while writing. The second element is
+      ** the virtual address being accessed. The "third array element specifies
+      ** the underlying NTSTATUS code that resulted in the exception". */
+      pWal->iSysErrno = (int)p->ExceptionRecord->ExceptionInformation[2];
+    }
+    return EXCEPTION_EXECUTE_HANDLER;
+  }
+  return EXCEPTION_CONTINUE_SEARCH;
+}
+
+/*
+** If one is configured, invoke the xTestCallback callback with 650 as
+** the argument. If it returns true, throw the same exception that is
+** thrown by the system if the *-shm file mapping is accessed after it
+** has been invalidated.
+*/
+static void sehInjectFault(Wal *pWal){
+  int res;
+  assert( pWal->nSehTry>0 );
+
+  res = sqlite3FaultSim(650);
+  if( res!=0 ){
+    ULONG_PTR aArg[3];
+    aArg[0] = 0;
+    aArg[1] = 0;
+    aArg[2] = (ULONG_PTR)res;
+    RaiseException(EXCEPTION_IN_PAGE_ERROR, 0, 3, (const ULONG_PTR*)aArg);
+  }
+}
+
+/*
+** There are two ways to use this macro. To set a pointer to be freed
+** if an exception is thrown:
+**
+**   SEH_FREE_ON_ERROR(0, pPtr);
+**
+** and to cancel the same:
+**
+**   SEH_FREE_ON_ERROR(pPtr, 0);
+**
+** In the first case, there must not already be a pointer registered to
+** be freed. In the second case, pPtr must be the registered pointer.
+*/
+#define SEH_FREE_ON_ERROR(X,Y) \
+  assert( (X==0 || Y==0) && pWal->pFree==X ); pWal->pFree = Y
+
+/*
+** There are two ways to use this macro. To arrange for pWal->apWiData[iPg]
+** to be set to pValue if an exception is thrown:
+**
+**   SEH_SET_ON_ERROR(iPg, pValue);
+**
+** and to cancel the same:
+**
+**   SEH_SET_ON_ERROR(0, 0);
+*/
+#define SEH_SET_ON_ERROR(X,Y)  pWal->iWiPg = X; pWal->pWiValue = Y
+
+#else
+# define SEH_TRY          VVA_ONLY(pWal->nSehTry++);
+# define SEH_EXCEPT(X)    VVA_ONLY(pWal->nSehTry--); assert( pWal->nSehTry==0 );
+# define SEH_INJECT_FAULT assert( pWal->nSehTry>0 );
+# define SEH_FREE_ON_ERROR(X,Y)
+# define SEH_SET_ON_ERROR(X,Y)
+#endif /* ifdef SQLITE_USE_SEH */
+
+
+/*
+** Obtain a pointer to the iPage'th page of the wal-index. The wal-index
+** is broken into pages of WALINDEX_PGSZ bytes. Wal-index pages are
+** numbered from zero.
+**
+** If the wal-index is currently smaller the iPage pages then the size
+** of the wal-index might be increased, but only if it is safe to do
+** so.  It is safe to enlarge the wal-index if pWal->writeLock is true
+** or pWal->exclusiveMode==WAL_HEAPMEMORY_MODE.
+**
+** Three possible result scenarios:
+**
+**   (1)  rc==SQLITE_OK    and *ppPage==Requested-Wal-Index-Page
+**   (2)  rc>=SQLITE_ERROR and *ppPage==NULL
+**   (3)  rc==SQLITE_OK    and *ppPage==NULL  // only if iPage==0
+**
+** Scenario (3) can only occur when pWal->writeLock is false and iPage==0
+*/
+static SQLITE_NOINLINE int walIndexPageRealloc(
+  Wal *pWal,               /* The WAL context */
+  int iPage,               /* The page we seek */
+  volatile u32 **ppPage    /* Write the page pointer here */
+){
+  int rc = SQLITE_OK;
+
+  /* Enlarge the pWal->apWiData[] array if required */
+  if( pWal->nWiData<=iPage ){
+    sqlite3_int64 nByte = sizeof(u32*)*(iPage+1);
+    volatile u32 **apNew;
+    apNew = (volatile u32 **)sqlite3Realloc((void *)pWal->apWiData, nByte);
+    if( !apNew ){
+      *ppPage = 0;
+      return SQLITE_NOMEM_BKPT;
+    }
+    memset((void*)&apNew[pWal->nWiData], 0,
+           sizeof(u32*)*(iPage+1-pWal->nWiData));
+    pWal->apWiData = apNew;
+    pWal->nWiData = iPage+1;
+  }
+
+  /* Request a pointer to the required page from the VFS */
+  assert( pWal->apWiData[iPage]==0 );
+  if( pWal->exclusiveMode==WAL_HEAPMEMORY_MODE ){
+    pWal->apWiData[iPage] = (u32 volatile *)sqlite3MallocZero(WALINDEX_PGSZ);
+    if( !pWal->apWiData[iPage] ) rc = SQLITE_NOMEM_BKPT;
+  }else{
+    rc = sqlite3OsShmMap(pWal->pDbFd, iPage, WALINDEX_PGSZ,
+        pWal->writeLock, (void volatile **)&pWal->apWiData[iPage]
+    );
+    assert( pWal->apWiData[iPage]!=0
+         || rc!=SQLITE_OK
+         || (pWal->writeLock==0 && iPage==0) );
+    testcase( pWal->apWiData[iPage]==0 && rc==SQLITE_OK );
+    if( rc==SQLITE_OK ){
+      if( iPage>0 && sqlite3FaultSim(600) ) rc = SQLITE_NOMEM;
+    }else if( (rc&0xff)==SQLITE_READONLY ){
+      pWal->readOnly |= WAL_SHM_RDONLY;
+      if( rc==SQLITE_READONLY ){
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+  *ppPage = pWal->apWiData[iPage];
+  assert( iPage==0 || *ppPage || rc!=SQLITE_OK );
+  return rc;
+}
+static int walIndexPage(
+  Wal *pWal,               /* The WAL context */
+  int iPage,               /* The page we seek */
+  volatile u32 **ppPage    /* Write the page pointer here */
+){
+  SEH_INJECT_FAULT;
+  if( pWal->nWiData<=iPage || (*ppPage = pWal->apWiData[iPage])==0 ){
+    return walIndexPageRealloc(pWal, iPage, ppPage);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return a pointer to the WalCkptInfo structure in the wal-index.
+*/
+static volatile WalCkptInfo *walCkptInfo(Wal *pWal){
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+  SEH_INJECT_FAULT;
+  return (volatile WalCkptInfo*)&(pWal->apWiData[0][sizeof(WalIndexHdr)/2]);
+}
+
+/*
+** Return a pointer to the WalIndexHdr structure in the wal-index.
+*/
+static volatile WalIndexHdr *walIndexHdr(Wal *pWal){
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+  SEH_INJECT_FAULT;
+  return (volatile WalIndexHdr*)pWal->apWiData[0];
+}
+
+/*
+** The argument to this macro must be of type u32. On a little-endian
+** architecture, it returns the u32 value that results from interpreting
+** the 4 bytes as a big-endian value. On a big-endian architecture, it
+** returns the value that would be produced by interpreting the 4 bytes
+** of the input value as a little-endian integer.
+*/
+#define BYTESWAP32(x) ( \
+    (((x)&0x000000FF)<<24) + (((x)&0x0000FF00)<<8)  \
+  + (((x)&0x00FF0000)>>8)  + (((x)&0xFF000000)>>24) \
+)
+
+/*
+** Generate or extend an 8 byte checksum based on the data in
+** array aByte[] and the initial values of aIn[0] and aIn[1] (or
+** initial values of 0 and 0 if aIn==NULL).
+**
+** The checksum is written back into aOut[] before returning.
+**
+** nByte must be a positive multiple of 8.
+*/
+static void walChecksumBytes(
+  int nativeCksum, /* True for native byte-order, false for non-native */
+  u8 *a,           /* Content to be checksummed */
+  int nByte,       /* Bytes of content in a[].  Must be a multiple of 8. */
+  const u32 *aIn,  /* Initial checksum value input */
+  u32 *aOut        /* OUT: Final checksum value output */
+){
+  u32 s1, s2;
+  u32 *aData = (u32 *)a;
+  u32 *aEnd = (u32 *)&a[nByte];
+
+  if( aIn ){
+    s1 = aIn[0];
+    s2 = aIn[1];
+  }else{
+    s1 = s2 = 0;
+  }
+
+  assert( nByte>=8 );
+  assert( (nByte&0x00000007)==0 );
+  assert( nByte<=65536 );
+  assert( nByte%4==0 );
+
+  if( !nativeCksum ){
+    do {
+      s1 += BYTESWAP32(aData[0]) + s2;
+      s2 += BYTESWAP32(aData[1]) + s1;
+      aData += 2;
+    }while( aData<aEnd );
+  }else if( nByte%64==0 ){
+    do {
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+    }while( aData<aEnd );
+  }else{
+    do {
+      s1 += *aData++ + s2;
+      s2 += *aData++ + s1;
+    }while( aData<aEnd );
+  }
+  assert( aData==aEnd );
+
+  aOut[0] = s1;
+  aOut[1] = s2;
+}
+
+/*
+** If there is the possibility of concurrent access to the SHM file
+** from multiple threads and/or processes, then do a memory barrier.
+*/
+static void walShmBarrier(Wal *pWal){
+  if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
+    sqlite3OsShmBarrier(pWal->pDbFd);
+  }
+}
+
+/*
+** Add the SQLITE_NO_TSAN as part of the return-type of a function
+** definition as a hint that the function contains constructs that
+** might give false-positive TSAN warnings.
+**
+** See tag-20200519-1.
+*/
+#if defined(__clang__) && !defined(SQLITE_NO_TSAN)
+# define SQLITE_NO_TSAN __attribute__((no_sanitize_thread))
+#else
+# define SQLITE_NO_TSAN
+#endif
+
+/*
+** Write the header information in pWal->hdr into the wal-index.
+**
+** The checksum on pWal->hdr is updated before it is written.
+*/
+static SQLITE_NO_TSAN void walIndexWriteHdr(Wal *pWal){
+  volatile WalIndexHdr *aHdr = walIndexHdr(pWal);
+  const int nCksum = offsetof(WalIndexHdr, aCksum);
+
+  assert( pWal->writeLock );
+  pWal->hdr.isInit = 1;
+  pWal->hdr.iVersion = WALINDEX_MAX_VERSION;
+  walChecksumBytes(1, (u8*)&pWal->hdr, nCksum, 0, pWal->hdr.aCksum);
+  /* Possible TSAN false-positive.  See tag-20200519-1 */
+  memcpy((void*)&aHdr[1], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
+  walShmBarrier(pWal);
+  memcpy((void*)&aHdr[0], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
+}
+
+/*
+** This function encodes a single frame header and writes it to a buffer
+** supplied by the caller. A frame-header is made up of a series of
+** 4-byte big-endian integers, as follows:
+**
+**     0: Page number.
+**     4: For commit records, the size of the database image in pages
+**        after the commit. For all other records, zero.
+**     8: Salt-1 (copied from the wal-header)
+**    12: Salt-2 (copied from the wal-header)
+**    16: Checksum-1.
+**    20: Checksum-2.
+*/
+static void walEncodeFrame(
+  Wal *pWal,                      /* The write-ahead log */
+  u32 iPage,                      /* Database page number for frame */
+  u32 nTruncate,                  /* New db size (or 0 for non-commit frames) */
+  u8 *aData,                      /* Pointer to page data */
+  u8 *aFrame                      /* OUT: Write encoded frame here */
+){
+  int nativeCksum;                /* True for native byte-order checksums */
+  u32 *aCksum = pWal->hdr.aFrameCksum;
+  assert( WAL_FRAME_HDRSIZE==24 );
+  sqlite3Put4byte(&aFrame[0], iPage);
+  sqlite3Put4byte(&aFrame[4], nTruncate);
+  if( pWal->iReCksum==0 ){
+    memcpy(&aFrame[8], pWal->hdr.aSalt, 8);
+
+    nativeCksum = (pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN);
+    walChecksumBytes(nativeCksum, aFrame, 8, aCksum, aCksum);
+    walChecksumBytes(nativeCksum, aData, pWal->szPage, aCksum, aCksum);
+
+    sqlite3Put4byte(&aFrame[16], aCksum[0]);
+    sqlite3Put4byte(&aFrame[20], aCksum[1]);
+  }else{
+    memset(&aFrame[8], 0, 16);
+  }
+}
+
+/*
+** Check to see if the frame with header in aFrame[] and content
+** in aData[] is valid.  If it is a valid frame, fill *piPage and
+** *pnTruncate and return true.  Return if the frame is not valid.
+*/
+static int walDecodeFrame(
+  Wal *pWal,                      /* The write-ahead log */
+  u32 *piPage,                    /* OUT: Database page number for frame */
+  u32 *pnTruncate,                /* OUT: New db size (or 0 if not commit) */
+  u8 *aData,                      /* Pointer to page data (for checksum) */
+  u8 *aFrame                      /* Frame data */
+){
+  int nativeCksum;                /* True for native byte-order checksums */
+  u32 *aCksum = pWal->hdr.aFrameCksum;
+  u32 pgno;                       /* Page number of the frame */
+  assert( WAL_FRAME_HDRSIZE==24 );
+
+  /* A frame is only valid if the salt values in the frame-header
+  ** match the salt values in the wal-header.
+  */
+  if( memcmp(&pWal->hdr.aSalt, &aFrame[8], 8)!=0 ){
+    return 0;
+  }
+
+  /* A frame is only valid if the page number is greater than zero.
+  */
+  pgno = sqlite3Get4byte(&aFrame[0]);
+  if( pgno==0 ){
+    return 0;
+  }
+
+  /* A frame is only valid if a checksum of the WAL header,
+  ** all prior frames, the first 16 bytes of this frame-header,
+  ** and the frame-data matches the checksum in the last 8
+  ** bytes of this frame-header.
+  */
+  nativeCksum = (pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN);
+  walChecksumBytes(nativeCksum, aFrame, 8, aCksum, aCksum);
+  walChecksumBytes(nativeCksum, aData, pWal->szPage, aCksum, aCksum);
+  if( aCksum[0]!=sqlite3Get4byte(&aFrame[16])
+   || aCksum[1]!=sqlite3Get4byte(&aFrame[20])
+  ){
+    /* Checksum failed. */
+    return 0;
+  }
+
+  /* If we reach this point, the frame is valid.  Return the page number
+  ** and the new database size.
+  */
+  *piPage = pgno;
+  *pnTruncate = sqlite3Get4byte(&aFrame[4]);
+  return 1;
+}
+
+
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+/*
+** Names of locks.  This routine is used to provide debugging output and is not
+** a part of an ordinary build.
+*/
+static const char *walLockName(int lockIdx){
+  if( lockIdx==WAL_WRITE_LOCK ){
+    return "WRITE-LOCK";
+  }else if( lockIdx==WAL_CKPT_LOCK ){
+    return "CKPT-LOCK";
+  }else if( lockIdx==WAL_RECOVER_LOCK ){
+    return "RECOVER-LOCK";
+  }else{
+    static char zName[15];
+    sqlite3_snprintf(sizeof(zName), zName, "READ-LOCK[%d]",
+                     lockIdx-WAL_READ_LOCK(0));
+    return zName;
+  }
+}
+#endif /*defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */
+
+
+/*
+** Set or release locks on the WAL.  Locks are either shared or exclusive.
+** A lock cannot be moved directly between shared and exclusive - it must go
+** through the unlocked state first.
+**
+** In locking_mode=EXCLUSIVE, all of these routines become no-ops.
+*/
+static int walLockShared(Wal *pWal, int lockIdx){
+  int rc;
+  if( pWal->exclusiveMode ) return SQLITE_OK;
+  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
+                        SQLITE_SHM_LOCK | SQLITE_SHM_SHARED);
+  WALTRACE(("WAL%p: acquire SHARED-%s %s\n", pWal,
+            walLockName(lockIdx), rc ? "failed" : "ok"));
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && (rc&0xFF)!=SQLITE_BUSY); )
+#ifdef SQLITE_USE_SEH
+  if( rc==SQLITE_OK ) pWal->lockMask |= (1 << lockIdx);
+#endif
+  return rc;
+}
+static void walUnlockShared(Wal *pWal, int lockIdx){
+  if( pWal->exclusiveMode ) return;
+  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, 1,
+                         SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED);
+#ifdef SQLITE_USE_SEH
+  pWal->lockMask &= ~(1 << lockIdx);
+#endif
+  WALTRACE(("WAL%p: release SHARED-%s\n", pWal, walLockName(lockIdx)));
+}
+static int walLockExclusive(Wal *pWal, int lockIdx, int n){
+  int rc;
+  if( pWal->exclusiveMode ) return SQLITE_OK;
+  rc = sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
+                        SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE);
+  WALTRACE(("WAL%p: acquire EXCLUSIVE-%s cnt=%d %s\n", pWal,
+            walLockName(lockIdx), n, rc ? "failed" : "ok"));
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && (rc&0xFF)!=SQLITE_BUSY); )
+#ifdef SQLITE_USE_SEH
+  if( rc==SQLITE_OK ){
+    pWal->lockMask |= (((1<<n)-1) << (SQLITE_SHM_NLOCK+lockIdx));
+  }
+#endif
+  return rc;
+}
+static void walUnlockExclusive(Wal *pWal, int lockIdx, int n){
+  if( pWal->exclusiveMode ) return;
+  (void)sqlite3OsShmLock(pWal->pDbFd, lockIdx, n,
+                         SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE);
+#ifdef SQLITE_USE_SEH
+  pWal->lockMask &= ~(((1<<n)-1) << (SQLITE_SHM_NLOCK+lockIdx));
+#endif
+  WALTRACE(("WAL%p: release EXCLUSIVE-%s cnt=%d\n", pWal,
+             walLockName(lockIdx), n));
+}
+
+/*
+** Compute a hash on a page number.  The resulting hash value must land
+** between 0 and (HASHTABLE_NSLOT-1).  The walHashNext() function advances
+** the hash to the next value in the event of a collision.
+*/
+static int walHash(u32 iPage){
+  assert( iPage>0 );
+  assert( (HASHTABLE_NSLOT & (HASHTABLE_NSLOT-1))==0 );
+  return (iPage*HASHTABLE_HASH_1) & (HASHTABLE_NSLOT-1);
+}
+static int walNextHash(int iPriorHash){
+  return (iPriorHash+1)&(HASHTABLE_NSLOT-1);
+}
+
+/*
+** An instance of the WalHashLoc object is used to describe the location
+** of a page hash table in the wal-index.  This becomes the return value
+** from walHashGet().
+*/
+typedef struct WalHashLoc WalHashLoc;
+struct WalHashLoc {
+  volatile ht_slot *aHash;  /* Start of the wal-index hash table */
+  volatile u32 *aPgno;      /* aPgno[1] is the page of first frame indexed */
+  u32 iZero;                /* One less than the frame number of first indexed*/
+};
+
+/*
+** Return pointers to the hash table and page number array stored on
+** page iHash of the wal-index. The wal-index is broken into 32KB pages
+** numbered starting from 0.
+**
+** Set output variable pLoc->aHash to point to the start of the hash table
+** in the wal-index file. Set pLoc->iZero to one less than the frame
+** number of the first frame indexed by this hash table. If a
+** slot in the hash table is set to N, it refers to frame number
+** (pLoc->iZero+N) in the log.
+**
+** Finally, set pLoc->aPgno so that pLoc->aPgno[0] is the page number of the
+** first frame indexed by the hash table, frame (pLoc->iZero).
+*/
+static int walHashGet(
+  Wal *pWal,                      /* WAL handle */
+  int iHash,                      /* Find the iHash'th table */
+  WalHashLoc *pLoc                /* OUT: Hash table location */
+){
+  int rc;                         /* Return code */
+
+  rc = walIndexPage(pWal, iHash, &pLoc->aPgno);
+  assert( rc==SQLITE_OK || iHash>0 );
+
+  if( pLoc->aPgno ){
+    pLoc->aHash = (volatile ht_slot *)&pLoc->aPgno[HASHTABLE_NPAGE];
+    if( iHash==0 ){
+      pLoc->aPgno = &pLoc->aPgno[WALINDEX_HDR_SIZE/sizeof(u32)];
+      pLoc->iZero = 0;
+    }else{
+      pLoc->iZero = HASHTABLE_NPAGE_ONE + (iHash-1)*HASHTABLE_NPAGE;
+    }
+  }else if( NEVER(rc==SQLITE_OK) ){
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** Return the number of the wal-index page that contains the hash-table
+** and page-number array that contain entries corresponding to WAL frame
+** iFrame. The wal-index is broken up into 32KB pages. Wal-index pages
+** are numbered starting from 0.
+*/
+static int walFramePage(u32 iFrame){
+  int iHash = (iFrame+HASHTABLE_NPAGE-HASHTABLE_NPAGE_ONE-1) / HASHTABLE_NPAGE;
+  assert( (iHash==0 || iFrame>HASHTABLE_NPAGE_ONE)
+       && (iHash>=1 || iFrame<=HASHTABLE_NPAGE_ONE)
+       && (iHash<=1 || iFrame>(HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE))
+       && (iHash>=2 || iFrame<=HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE)
+       && (iHash<=2 || iFrame>(HASHTABLE_NPAGE_ONE+2*HASHTABLE_NPAGE))
+  );
+  assert( iHash>=0 );
+  return iHash;
+}
+
+/*
+** Return the page number associated with frame iFrame in this WAL.
+*/
+static u32 walFramePgno(Wal *pWal, u32 iFrame){
+  int iHash = walFramePage(iFrame);
+  SEH_INJECT_FAULT;
+  if( iHash==0 ){
+    return pWal->apWiData[0][WALINDEX_HDR_SIZE/sizeof(u32) + iFrame - 1];
+  }
+  return pWal->apWiData[iHash][(iFrame-1-HASHTABLE_NPAGE_ONE)%HASHTABLE_NPAGE];
+}
+
+/*
+** Remove entries from the hash table that point to WAL slots greater
+** than pWal->hdr.mxFrame.
+**
+** This function is called whenever pWal->hdr.mxFrame is decreased due
+** to a rollback or savepoint.
+**
+** At most only the hash table containing pWal->hdr.mxFrame needs to be
+** updated.  Any later hash tables will be automatically cleared when
+** pWal->hdr.mxFrame advances to the point where those hash tables are
+** actually needed.
+*/
+static void walCleanupHash(Wal *pWal){
+  WalHashLoc sLoc;                /* Hash table location */
+  int iLimit = 0;                 /* Zero values greater than this */
+  int nByte;                      /* Number of bytes to zero in aPgno[] */
+  int i;                          /* Used to iterate through aHash[] */
+
+  assert( pWal->writeLock );
+  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE-1 );
+  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE );
+  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE+1 );
+
+  if( pWal->hdr.mxFrame==0 ) return;
+
+  /* Obtain pointers to the hash-table and page-number array containing
+  ** the entry that corresponds to frame pWal->hdr.mxFrame. It is guaranteed
+  ** that the page said hash-table and array reside on is already mapped.(1)
+  */
+  assert( pWal->nWiData>walFramePage(pWal->hdr.mxFrame) );
+  assert( pWal->apWiData[walFramePage(pWal->hdr.mxFrame)] );
+  i = walHashGet(pWal, walFramePage(pWal->hdr.mxFrame), &sLoc);
+  if( NEVER(i) ) return; /* Defense-in-depth, in case (1) above is wrong */
+
+  /* Zero all hash-table entries that correspond to frame numbers greater
+  ** than pWal->hdr.mxFrame.
+  */
+  iLimit = pWal->hdr.mxFrame - sLoc.iZero;
+  assert( iLimit>0 );
+  for(i=0; i<HASHTABLE_NSLOT; i++){
+    if( sLoc.aHash[i]>iLimit ){
+      sLoc.aHash[i] = 0;
+    }
+  }
+
+  /* Zero the entries in the aPgno array that correspond to frames with
+  ** frame numbers greater than pWal->hdr.mxFrame.
+  */
+  nByte = (int)((char *)sLoc.aHash - (char *)&sLoc.aPgno[iLimit]);
+  assert( nByte>=0 );
+  memset((void *)&sLoc.aPgno[iLimit], 0, nByte);
+
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+  /* Verify that the every entry in the mapping region is still reachable
+  ** via the hash table even after the cleanup.
+  */
+  if( iLimit ){
+    int j;           /* Loop counter */
+    int iKey;        /* Hash key */
+    for(j=0; j<iLimit; j++){
+      for(iKey=walHash(sLoc.aPgno[j]);sLoc.aHash[iKey];iKey=walNextHash(iKey)){
+        if( sLoc.aHash[iKey]==j+1 ) break;
+      }
+      assert( sLoc.aHash[iKey]==j+1 );
+    }
+  }
+#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
+}
+
+
+/*
+** Set an entry in the wal-index that will map database page number
+** pPage into WAL frame iFrame.
+*/
+static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
+  int rc;                         /* Return code */
+  WalHashLoc sLoc;                /* Wal-index hash table location */
+
+  rc = walHashGet(pWal, walFramePage(iFrame), &sLoc);
+
+  /* Assuming the wal-index file was successfully mapped, populate the
+  ** page number array and hash table entry.
+  */
+  if( rc==SQLITE_OK ){
+    int iKey;                     /* Hash table key */
+    int idx;                      /* Value to write to hash-table slot */
+    int nCollide;                 /* Number of hash collisions */
+
+    idx = iFrame - sLoc.iZero;
+    assert( idx <= HASHTABLE_NSLOT/2 + 1 );
+
+    /* If this is the first entry to be added to this hash-table, zero the
+    ** entire hash table and aPgno[] array before proceeding.
+    */
+    if( idx==1 ){
+      int nByte = (int)((u8*)&sLoc.aHash[HASHTABLE_NSLOT] - (u8*)sLoc.aPgno);
+      assert( nByte>=0 );
+      memset((void*)sLoc.aPgno, 0, nByte);
+    }
+
+    /* If the entry in aPgno[] is already set, then the previous writer
+    ** must have exited unexpectedly in the middle of a transaction (after
+    ** writing one or more dirty pages to the WAL to free up memory).
+    ** Remove the remnants of that writers uncommitted transaction from
+    ** the hash-table before writing any new entries.
+    */
+    if( sLoc.aPgno[idx-1] ){
+      walCleanupHash(pWal);
+      assert( !sLoc.aPgno[idx-1] );
+    }
+
+    /* Write the aPgno[] array entry and the hash-table slot. */
+    nCollide = idx;
+    for(iKey=walHash(iPage); sLoc.aHash[iKey]; iKey=walNextHash(iKey)){
+      if( (nCollide--)==0 ) return SQLITE_CORRUPT_BKPT;
+    }
+    sLoc.aPgno[idx-1] = iPage;
+    AtomicStore(&sLoc.aHash[iKey], (ht_slot)idx);
+
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+    /* Verify that the number of entries in the hash table exactly equals
+    ** the number of entries in the mapping region.
+    */
+    {
+      int i;           /* Loop counter */
+      int nEntry = 0;  /* Number of entries in the hash table */
+      for(i=0; i<HASHTABLE_NSLOT; i++){ if( sLoc.aHash[i] ) nEntry++; }
+      assert( nEntry==idx );
+    }
+
+    /* Verify that the every entry in the mapping region is reachable
+    ** via the hash table.  This turns out to be a really, really expensive
+    ** thing to check, so only do this occasionally - not on every
+    ** iteration.
+    */
+    if( (idx&0x3ff)==0 ){
+      int i;           /* Loop counter */
+      for(i=0; i<idx; i++){
+        for(iKey=walHash(sLoc.aPgno[i]);
+            sLoc.aHash[iKey];
+            iKey=walNextHash(iKey)){
+          if( sLoc.aHash[iKey]==i+1 ) break;
+        }
+        assert( sLoc.aHash[iKey]==i+1 );
+      }
+    }
+#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
+  }
+
+  return rc;
+}
+
+
+/*
+** Recover the wal-index by reading the write-ahead log file.
+**
+** This routine first tries to establish an exclusive lock on the
+** wal-index to prevent other threads/processes from doing anything
+** with the WAL or wal-index while recovery is running.  The
+** WAL_RECOVER_LOCK is also held so that other threads will know
+** that this thread is running recovery.  If unable to establish
+** the necessary locks, this routine returns SQLITE_BUSY.
+*/
+static int walIndexRecover(Wal *pWal){
+  int rc;                         /* Return Code */
+  i64 nSize;                      /* Size of log file */
+  u32 aFrameCksum[2] = {0, 0};
+  int iLock;                      /* Lock offset to lock for checkpoint */
+
+  /* Obtain an exclusive lock on all byte in the locking range not already
+  ** locked by the caller. The caller is guaranteed to have locked the
+  ** WAL_WRITE_LOCK byte, and may have also locked the WAL_CKPT_LOCK byte.
+  ** If successful, the same bytes that are locked here are unlocked before
+  ** this function returns.
+  */
+  assert( pWal->ckptLock==1 || pWal->ckptLock==0 );
+  assert( WAL_ALL_BUT_WRITE==WAL_WRITE_LOCK+1 );
+  assert( WAL_CKPT_LOCK==WAL_ALL_BUT_WRITE );
+  assert( pWal->writeLock );
+  iLock = WAL_ALL_BUT_WRITE + pWal->ckptLock;
+  rc = walLockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
+  if( rc ){
+    return rc;
+  }
+
+  WALTRACE(("WAL%p: recovery begin...\n", pWal));
+
+  memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
+
+  rc = sqlite3OsFileSize(pWal->pWalFd, &nSize);
+  if( rc!=SQLITE_OK ){
+    goto recovery_error;
+  }
+
+  if( nSize>WAL_HDRSIZE ){
+    u8 aBuf[WAL_HDRSIZE];         /* Buffer to load WAL header into */
+    u32 *aPrivate = 0;            /* Heap copy of *-shm hash being populated */
+    u8 *aFrame = 0;               /* Malloc'd buffer to load entire frame */
+    int szFrame;                  /* Number of bytes in buffer aFrame[] */
+    u8 *aData;                    /* Pointer to data part of aFrame buffer */
+    int szPage;                   /* Page size according to the log */
+    u32 magic;                    /* Magic value read from WAL header */
+    u32 version;                  /* Magic value read from WAL header */
+    int isValid;                  /* True if this frame is valid */
+    u32 iPg;                      /* Current 32KB wal-index page */
+    u32 iLastFrame;               /* Last frame in wal, based on nSize alone */
+
+    /* Read in the WAL header. */
+    rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
+    if( rc!=SQLITE_OK ){
+      goto recovery_error;
+    }
+
+    /* If the database page size is not a power of two, or is greater than
+    ** SQLITE_MAX_PAGE_SIZE, conclude that the WAL file contains no valid
+    ** data. Similarly, if the 'magic' value is invalid, ignore the whole
+    ** WAL file.
+    */
+    magic = sqlite3Get4byte(&aBuf[0]);
+    szPage = sqlite3Get4byte(&aBuf[8]);
+    if( (magic&0xFFFFFFFE)!=WAL_MAGIC
+     || szPage&(szPage-1)
+     || szPage>SQLITE_MAX_PAGE_SIZE
+     || szPage<512
+    ){
+      goto finished;
+    }
+    pWal->hdr.bigEndCksum = (u8)(magic&0x00000001);
+    pWal->szPage = szPage;
+    pWal->nCkpt = sqlite3Get4byte(&aBuf[12]);
+    memcpy(&pWal->hdr.aSalt, &aBuf[16], 8);
+
+    /* Verify that the WAL header checksum is correct */
+    walChecksumBytes(pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN,
+        aBuf, WAL_HDRSIZE-2*4, 0, pWal->hdr.aFrameCksum
+    );
+    if( pWal->hdr.aFrameCksum[0]!=sqlite3Get4byte(&aBuf[24])
+     || pWal->hdr.aFrameCksum[1]!=sqlite3Get4byte(&aBuf[28])
+    ){
+      goto finished;
+    }
+
+    /* Verify that the version number on the WAL format is one that
+    ** are able to understand */
+    version = sqlite3Get4byte(&aBuf[4]);
+    if( version!=WAL_MAX_VERSION ){
+      rc = SQLITE_CANTOPEN_BKPT;
+      goto finished;
+    }
+
+    /* Malloc a buffer to read frames into. */
+    szFrame = szPage + WAL_FRAME_HDRSIZE;
+    aFrame = (u8 *)sqlite3_malloc64(szFrame + WALINDEX_PGSZ);
+    SEH_FREE_ON_ERROR(0, aFrame);
+    if( !aFrame ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto recovery_error;
+    }
+    aData = &aFrame[WAL_FRAME_HDRSIZE];
+    aPrivate = (u32*)&aData[szPage];
+
+    /* Read all frames from the log file. */
+    iLastFrame = (nSize - WAL_HDRSIZE) / szFrame;
+    for(iPg=0; iPg<=(u32)walFramePage(iLastFrame); iPg++){
+      u32 *aShare;
+      u32 iFrame;                 /* Index of last frame read */
+      u32 iLast = MIN(iLastFrame, HASHTABLE_NPAGE_ONE+iPg*HASHTABLE_NPAGE);
+      u32 iFirst = 1 + (iPg==0?0:HASHTABLE_NPAGE_ONE+(iPg-1)*HASHTABLE_NPAGE);
+      u32 nHdr, nHdr32;
+      rc = walIndexPage(pWal, iPg, (volatile u32**)&aShare);
+      assert( aShare!=0 || rc!=SQLITE_OK );
+      if( aShare==0 ) break;
+      SEH_SET_ON_ERROR(iPg, aShare);
+      pWal->apWiData[iPg] = aPrivate;
+
+      for(iFrame=iFirst; iFrame<=iLast; iFrame++){
+        i64 iOffset = walFrameOffset(iFrame, szPage);
+        u32 pgno;                 /* Database page number for frame */
+        u32 nTruncate;            /* dbsize field from frame header */
+
+        /* Read and decode the next log frame. */
+        rc = sqlite3OsRead(pWal->pWalFd, aFrame, szFrame, iOffset);
+        if( rc!=SQLITE_OK ) break;
+        isValid = walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame);
+        if( !isValid ) break;
+        rc = walIndexAppend(pWal, iFrame, pgno);
+        if( NEVER(rc!=SQLITE_OK) ) break;
+
+        /* If nTruncate is non-zero, this is a commit record. */
+        if( nTruncate ){
+          pWal->hdr.mxFrame = iFrame;
+          pWal->hdr.nPage = nTruncate;
+          pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
+          testcase( szPage<=32768 );
+          testcase( szPage>=65536 );
+          aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
+          aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
+        }
+      }
+      pWal->apWiData[iPg] = aShare;
+      SEH_SET_ON_ERROR(0,0);
+      nHdr = (iPg==0 ? WALINDEX_HDR_SIZE : 0);
+      nHdr32 = nHdr / sizeof(u32);
+#ifndef SQLITE_SAFER_WALINDEX_RECOVERY
+      /* Memcpy() should work fine here, on all reasonable implementations.
+      ** Technically, memcpy() might change the destination to some
+      ** intermediate value before setting to the final value, and that might
+      ** cause a concurrent reader to malfunction.  Memcpy() is allowed to
+      ** do that, according to the spec, but no memcpy() implementation that
+      ** we know of actually does that, which is why we say that memcpy()
+      ** is safe for this.  Memcpy() is certainly a lot faster.
+      */
+      memcpy(&aShare[nHdr32], &aPrivate[nHdr32], WALINDEX_PGSZ-nHdr);
+#else
+      /* In the event that some platform is found for which memcpy()
+      ** changes the destination to some intermediate value before
+      ** setting the final value, this alternative copy routine is
+      ** provided.
+      */
+      {
+        int i;
+        for(i=nHdr32; i<WALINDEX_PGSZ/sizeof(u32); i++){
+          if( aShare[i]!=aPrivate[i] ){
+            /* Atomic memory operations are not required here because if
+            ** the value needs to be changed, that means it is not being
+            ** accessed concurrently. */
+            aShare[i] = aPrivate[i];
+          }
+        }
+      }
+#endif
+      SEH_INJECT_FAULT;
+      if( iFrame<=iLast ) break;
+    }
+
+    SEH_FREE_ON_ERROR(aFrame, 0);
+    sqlite3_free(aFrame);
+  }
+
+finished:
+  if( rc==SQLITE_OK ){
+    volatile WalCkptInfo *pInfo;
+    int i;
+    pWal->hdr.aFrameCksum[0] = aFrameCksum[0];
+    pWal->hdr.aFrameCksum[1] = aFrameCksum[1];
+    walIndexWriteHdr(pWal);
+
+    /* Reset the checkpoint-header. This is safe because this thread is
+    ** currently holding locks that exclude all other writers and
+    ** checkpointers. Then set the values of read-mark slots 1 through N.
+    */
+    pInfo = walCkptInfo(pWal);
+    pInfo->nBackfill = 0;
+    pInfo->nBackfillAttempted = pWal->hdr.mxFrame;
+    pInfo->aReadMark[0] = 0;
+    for(i=1; i<WAL_NREADER; i++){
+      rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
+      if( rc==SQLITE_OK ){
+        if( i==1 && pWal->hdr.mxFrame ){
+          pInfo->aReadMark[i] = pWal->hdr.mxFrame;
+        }else{
+          pInfo->aReadMark[i] = READMARK_NOT_USED;
+        }
+        SEH_INJECT_FAULT;
+        walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
+      }else if( rc!=SQLITE_BUSY ){
+        goto recovery_error;
+      }
+    }
+
+    /* If more than one frame was recovered from the log file, report an
+    ** event via sqlite3_log(). This is to help with identifying performance
+    ** problems caused by applications routinely shutting down without
+    ** checkpointing the log file.
+    */
+    if( pWal->hdr.nPage ){
+      sqlite3_log(SQLITE_NOTICE_RECOVER_WAL,
+          "recovered %d frames from WAL file %s",
+          pWal->hdr.mxFrame, pWal->zWalName
+      );
+    }
+  }
+
+recovery_error:
+  WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
+  walUnlockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
+  return rc;
+}
+
+/*
+** Close an open wal-index.
+*/
+static void walIndexClose(Wal *pWal, int isDelete){
+  if( pWal->exclusiveMode==WAL_HEAPMEMORY_MODE || pWal->bShmUnreliable ){
+    int i;
+    for(i=0; i<pWal->nWiData; i++){
+      sqlite3_free((void *)pWal->apWiData[i]);
+      pWal->apWiData[i] = 0;
+    }
+  }
+  if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
+    sqlite3OsShmUnmap(pWal->pDbFd, isDelete);
+  }
+}
+
+/*
+** Open a connection to the WAL file zWalName. The database file must
+** already be opened on connection pDbFd. The buffer that zWalName points
+** to must remain valid for the lifetime of the returned Wal* handle.
+**
+** A SHARED lock should be held on the database file when this function
+** is called. The purpose of this SHARED lock is to prevent any other
+** client from unlinking the WAL or wal-index file. If another process
+** were to do this just after this client opened one of these files, the
+** system would be badly broken.
+**
+** If the log file is successfully opened, SQLITE_OK is returned and
+** *ppWal is set to point to a new WAL handle. If an error occurs,
+** an SQLite error code is returned and *ppWal is left unmodified.
+*/
+SQLITE_PRIVATE int sqlite3WalOpen(
+  sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
+  sqlite3_file *pDbFd,            /* The open database file */
+  const char *zWalName,           /* Name of the WAL file */
+  int bNoShm,                     /* True to run in heap-memory mode */
+  i64 mxWalSize,                  /* Truncate WAL to this size on reset */
+  Wal **ppWal                     /* OUT: Allocated Wal handle */
+){
+  int rc;                         /* Return Code */
+  Wal *pRet;                      /* Object to allocate and return */
+  int flags;                      /* Flags passed to OsOpen() */
+
+  assert( zWalName && zWalName[0] );
+  assert( pDbFd );
+
+  /* Verify the values of various constants.  Any changes to the values
+  ** of these constants would result in an incompatible on-disk format
+  ** for the -shm file.  Any change that causes one of these asserts to
+  ** fail is a backward compatibility problem, even if the change otherwise
+  ** works.
+  **
+  ** This table also serves as a helpful cross-reference when trying to
+  ** interpret hex dumps of the -shm file.
+  */
+  assert(    48 ==  sizeof(WalIndexHdr)  );
+  assert(    40 ==  sizeof(WalCkptInfo)  );
+  assert(   120 ==  WALINDEX_LOCK_OFFSET );
+  assert(   136 ==  WALINDEX_HDR_SIZE    );
+  assert(  4096 ==  HASHTABLE_NPAGE      );
+  assert(  4062 ==  HASHTABLE_NPAGE_ONE  );
+  assert(  8192 ==  HASHTABLE_NSLOT      );
+  assert(   383 ==  HASHTABLE_HASH_1     );
+  assert( 32768 ==  WALINDEX_PGSZ        );
+  assert(     8 ==  SQLITE_SHM_NLOCK     );
+  assert(     5 ==  WAL_NREADER          );
+  assert(    24 ==  WAL_FRAME_HDRSIZE    );
+  assert(    32 ==  WAL_HDRSIZE          );
+  assert(   120 ==  WALINDEX_LOCK_OFFSET + WAL_WRITE_LOCK   );
+  assert(   121 ==  WALINDEX_LOCK_OFFSET + WAL_CKPT_LOCK    );
+  assert(   122 ==  WALINDEX_LOCK_OFFSET + WAL_RECOVER_LOCK );
+  assert(   123 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(0) );
+  assert(   124 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(1) );
+  assert(   125 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(2) );
+  assert(   126 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(3) );
+  assert(   127 ==  WALINDEX_LOCK_OFFSET + WAL_READ_LOCK(4) );
+
+  /* In the amalgamation, the os_unix.c and os_win.c source files come before
+  ** this source file.  Verify that the #defines of the locking byte offsets
+  ** in os_unix.c and os_win.c agree with the WALINDEX_LOCK_OFFSET value.
+  ** For that matter, if the lock offset ever changes from its initial design
+  ** value of 120, we need to know that so there is an assert() to check it.
+  */
+#ifdef WIN_SHM_BASE
+  assert( WIN_SHM_BASE==WALINDEX_LOCK_OFFSET );
+#endif
+#ifdef UNIX_SHM_BASE
+  assert( UNIX_SHM_BASE==WALINDEX_LOCK_OFFSET );
+#endif
+
+
+  /* Allocate an instance of struct Wal to return. */
+  *ppWal = 0;
+  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile);
+  if( !pRet ){
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  pRet->pVfs = pVfs;
+  pRet->pWalFd = (sqlite3_file *)&pRet[1];
+  pRet->pDbFd = pDbFd;
+  pRet->readLock = -1;
+  pRet->mxWalSize = mxWalSize;
+  pRet->zWalName = zWalName;
+  pRet->syncHeader = 1;
+  pRet->padToSectorBoundary = 1;
+  pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE);
+
+  /* Open file handle on the write-ahead log file. */
+  flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
+  rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags);
+  if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){
+    pRet->readOnly = WAL_RDONLY;
+  }
+
+  if( rc!=SQLITE_OK ){
+    walIndexClose(pRet, 0);
+    sqlite3OsClose(pRet->pWalFd);
+    sqlite3_free(pRet);
+  }else{
+    int iDC = sqlite3OsDeviceCharacteristics(pDbFd);
+    if( iDC & SQLITE_IOCAP_SEQUENTIAL ){ pRet->syncHeader = 0; }
+    if( iDC & SQLITE_IOCAP_POWERSAFE_OVERWRITE ){
+      pRet->padToSectorBoundary = 0;
+    }
+    *ppWal = pRet;
+    WALTRACE(("WAL%d: opened\n", pRet));
+  }
+  return rc;
+}
+
+/*
+** Change the size to which the WAL file is truncated on each reset.
+*/
+SQLITE_PRIVATE void sqlite3WalLimit(Wal *pWal, i64 iLimit){
+  if( pWal ) pWal->mxWalSize = iLimit;
+}
+
+/*
+** Find the smallest page number out of all pages held in the WAL that
+** has not been returned by any prior invocation of this method on the
+** same WalIterator object.   Write into *piFrame the frame index where
+** that page was last written into the WAL.  Write into *piPage the page
+** number.
+**
+** Return 0 on success.  If there are no pages in the WAL with a page
+** number larger than *piPage, then return 1.
+*/
+static int walIteratorNext(
+  WalIterator *p,               /* Iterator */
+  u32 *piPage,                  /* OUT: The page number of the next page */
+  u32 *piFrame                  /* OUT: Wal frame index of next page */
+){
+  u32 iMin;                     /* Result pgno must be greater than iMin */
+  u32 iRet = 0xFFFFFFFF;        /* 0xffffffff is never a valid page number */
+  int i;                        /* For looping through segments */
+
+  iMin = p->iPrior;
+  assert( iMin<0xffffffff );
+  for(i=p->nSegment-1; i>=0; i--){
+    struct WalSegment *pSegment = &p->aSegment[i];
+    while( pSegment->iNext<pSegment->nEntry ){
+      u32 iPg = pSegment->aPgno[pSegment->aIndex[pSegment->iNext]];
+      if( iPg>iMin ){
+        if( iPg<iRet ){
+          iRet = iPg;
+          *piFrame = pSegment->iZero + pSegment->aIndex[pSegment->iNext];
+        }
+        break;
+      }
+      pSegment->iNext++;
+    }
+  }
+
+  *piPage = p->iPrior = iRet;
+  return (iRet==0xFFFFFFFF);
+}
+
+/*
+** This function merges two sorted lists into a single sorted list.
+**
+** aLeft[] and aRight[] are arrays of indices.  The sort key is
+** aContent[aLeft[]] and aContent[aRight[]].  Upon entry, the following
+** is guaranteed for all J<K:
+**
+**        aContent[aLeft[J]] < aContent[aLeft[K]]
+**        aContent[aRight[J]] < aContent[aRight[K]]
+**
+** This routine overwrites aRight[] with a new (probably longer) sequence
+** of indices such that the aRight[] contains every index that appears in
+** either aLeft[] or the old aRight[] and such that the second condition
+** above is still met.
+**
+** The aContent[aLeft[X]] values will be unique for all X.  And the
+** aContent[aRight[X]] values will be unique too.  But there might be
+** one or more combinations of X and Y such that
+**
+**      aLeft[X]!=aRight[Y]  &&  aContent[aLeft[X]] == aContent[aRight[Y]]
+**
+** When that happens, omit the aLeft[X] and use the aRight[Y] index.
+*/
+static void walMerge(
+  const u32 *aContent,            /* Pages in wal - keys for the sort */
+  ht_slot *aLeft,                 /* IN: Left hand input list */
+  int nLeft,                      /* IN: Elements in array *paLeft */
+  ht_slot **paRight,              /* IN/OUT: Right hand input list */
+  int *pnRight,                   /* IN/OUT: Elements in *paRight */
+  ht_slot *aTmp                   /* Temporary buffer */
+){
+  int iLeft = 0;                  /* Current index in aLeft */
+  int iRight = 0;                 /* Current index in aRight */
+  int iOut = 0;                   /* Current index in output buffer */
+  int nRight = *pnRight;
+  ht_slot *aRight = *paRight;
+
+  assert( nLeft>0 && nRight>0 );
+  while( iRight<nRight || iLeft<nLeft ){
+    ht_slot logpage;
+    Pgno dbpage;
+
+    if( (iLeft<nLeft)
+     && (iRight>=nRight || aContent[aLeft[iLeft]]<aContent[aRight[iRight]])
+    ){
+      logpage = aLeft[iLeft++];
+    }else{
+      logpage = aRight[iRight++];
+    }
+    dbpage = aContent[logpage];
+
+    aTmp[iOut++] = logpage;
+    if( iLeft<nLeft && aContent[aLeft[iLeft]]==dbpage ) iLeft++;
+
+    assert( iLeft>=nLeft || aContent[aLeft[iLeft]]>dbpage );
+    assert( iRight>=nRight || aContent[aRight[iRight]]>dbpage );
+  }
+
+  *paRight = aLeft;
+  *pnRight = iOut;
+  memcpy(aLeft, aTmp, sizeof(aTmp[0])*iOut);
+}
+
+/*
+** Sort the elements in list aList using aContent[] as the sort key.
+** Remove elements with duplicate keys, preferring to keep the
+** larger aList[] values.
+**
+** The aList[] entries are indices into aContent[].  The values in
+** aList[] are to be sorted so that for all J<K:
+**
+**      aContent[aList[J]] < aContent[aList[K]]
+**
+** For any X and Y such that
+**
+**      aContent[aList[X]] == aContent[aList[Y]]
+**
+** Keep the larger of the two values aList[X] and aList[Y] and discard
+** the smaller.
+*/
+static void walMergesort(
+  const u32 *aContent,            /* Pages in wal */
+  ht_slot *aBuffer,               /* Buffer of at least *pnList items to use */
+  ht_slot *aList,                 /* IN/OUT: List to sort */
+  int *pnList                     /* IN/OUT: Number of elements in aList[] */
+){
+  struct Sublist {
+    int nList;                    /* Number of elements in aList */
+    ht_slot *aList;               /* Pointer to sub-list content */
+  };
+
+  const int nList = *pnList;      /* Size of input list */
+  int nMerge = 0;                 /* Number of elements in list aMerge */
+  ht_slot *aMerge = 0;            /* List to be merged */
+  int iList;                      /* Index into input list */
+  u32 iSub = 0;                   /* Index into aSub array */
+  struct Sublist aSub[13];        /* Array of sub-lists */
+
+  memset(aSub, 0, sizeof(aSub));
+  assert( nList<=HASHTABLE_NPAGE && nList>0 );
+  assert( HASHTABLE_NPAGE==(1<<(ArraySize(aSub)-1)) );
+
+  for(iList=0; iList<nList; iList++){
+    nMerge = 1;
+    aMerge = &aList[iList];
+    for(iSub=0; iList & (1<<iSub); iSub++){
+      struct Sublist *p;
+      assert( iSub<ArraySize(aSub) );
+      p = &aSub[iSub];
+      assert( p->aList && p->nList<=(1<<iSub) );
+      assert( p->aList==&aList[iList&~((2<<iSub)-1)] );
+      walMerge(aContent, p->aList, p->nList, &aMerge, &nMerge, aBuffer);
+    }
+    aSub[iSub].aList = aMerge;
+    aSub[iSub].nList = nMerge;
+  }
+
+  for(iSub++; iSub<ArraySize(aSub); iSub++){
+    if( nList & (1<<iSub) ){
+      struct Sublist *p;
+      assert( iSub<ArraySize(aSub) );
+      p = &aSub[iSub];
+      assert( p->nList<=(1<<iSub) );
+      assert( p->aList==&aList[nList&~((2<<iSub)-1)] );
+      walMerge(aContent, p->aList, p->nList, &aMerge, &nMerge, aBuffer);
+    }
+  }
+  assert( aMerge==aList );
+  *pnList = nMerge;
+
+#ifdef SQLITE_DEBUG
+  {
+    int i;
+    for(i=1; i<*pnList; i++){
+      assert( aContent[aList[i]] > aContent[aList[i-1]] );
+    }
+  }
+#endif
+}
+
+/*
+** Free an iterator allocated by walIteratorInit().
+*/
+static void walIteratorFree(WalIterator *p){
+  sqlite3_free(p);
+}
+
+/*
+** Construct a WalInterator object that can be used to loop over all
+** pages in the WAL following frame nBackfill in ascending order. Frames
+** nBackfill or earlier may be included - excluding them is an optimization
+** only. The caller must hold the checkpoint lock.
+**
+** On success, make *pp point to the newly allocated WalInterator object
+** return SQLITE_OK. Otherwise, return an error code. If this routine
+** returns an error, the value of *pp is undefined.
+**
+** The calling routine should invoke walIteratorFree() to destroy the
+** WalIterator object when it has finished with it.
+*/
+static int walIteratorInit(Wal *pWal, u32 nBackfill, WalIterator **pp){
+  WalIterator *p;                 /* Return value */
+  int nSegment;                   /* Number of segments to merge */
+  u32 iLast;                      /* Last frame in log */
+  sqlite3_int64 nByte;            /* Number of bytes to allocate */
+  int i;                          /* Iterator variable */
+  ht_slot *aTmp;                  /* Temp space used by merge-sort */
+  int rc = SQLITE_OK;             /* Return Code */
+
+  /* This routine only runs while holding the checkpoint lock. And
+  ** it only runs if there is actually content in the log (mxFrame>0).
+  */
+  assert( pWal->ckptLock && pWal->hdr.mxFrame>0 );
+  iLast = pWal->hdr.mxFrame;
+
+  /* Allocate space for the WalIterator object. */
+  nSegment = walFramePage(iLast) + 1;
+  nByte = sizeof(WalIterator)
+        + (nSegment-1)*sizeof(struct WalSegment)
+        + iLast*sizeof(ht_slot);
+  p = (WalIterator *)sqlite3_malloc64(nByte
+      + sizeof(ht_slot) * (iLast>HASHTABLE_NPAGE?HASHTABLE_NPAGE:iLast)
+  );
+  if( !p ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  memset(p, 0, nByte);
+  p->nSegment = nSegment;
+  aTmp = (ht_slot*)&(((u8*)p)[nByte]);
+  SEH_FREE_ON_ERROR(0, p);
+  for(i=walFramePage(nBackfill+1); rc==SQLITE_OK && i<nSegment; i++){
+    WalHashLoc sLoc;
+
+    rc = walHashGet(pWal, i, &sLoc);
+    if( rc==SQLITE_OK ){
+      int j;                      /* Counter variable */
+      int nEntry;                 /* Number of entries in this segment */
+      ht_slot *aIndex;            /* Sorted index for this segment */
+
+      if( (i+1)==nSegment ){
+        nEntry = (int)(iLast - sLoc.iZero);
+      }else{
+        nEntry = (int)((u32*)sLoc.aHash - (u32*)sLoc.aPgno);
+      }
+      aIndex = &((ht_slot *)&p->aSegment[p->nSegment])[sLoc.iZero];
+      sLoc.iZero++;
+
+      for(j=0; j<nEntry; j++){
+        aIndex[j] = (ht_slot)j;
+      }
+      walMergesort((u32 *)sLoc.aPgno, aTmp, aIndex, &nEntry);
+      p->aSegment[i].iZero = sLoc.iZero;
+      p->aSegment[i].nEntry = nEntry;
+      p->aSegment[i].aIndex = aIndex;
+      p->aSegment[i].aPgno = (u32 *)sLoc.aPgno;
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    SEH_FREE_ON_ERROR(p, 0);
+    walIteratorFree(p);
+    p = 0;
+  }
+  *pp = p;
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+
+
+/*
+** Attempt to enable blocking locks that block for nMs ms. Return 1 if
+** blocking locks are successfully enabled, or 0 otherwise.
+*/
+static int walEnableBlockingMs(Wal *pWal, int nMs){
+  int rc = sqlite3OsFileControl(
+      pWal->pDbFd, SQLITE_FCNTL_LOCK_TIMEOUT, (void*)&nMs
+  );
+  return (rc==SQLITE_OK);
+}
+
+/*
+** Attempt to enable blocking locks. Blocking locks are enabled only if (a)
+** they are supported by the VFS, and (b) the database handle is configured
+** with a busy-timeout. Return 1 if blocking locks are successfully enabled,
+** or 0 otherwise.
+*/
+static int walEnableBlocking(Wal *pWal){
+  int res = 0;
+  if( pWal->db ){
+    int tmout = pWal->db->busyTimeout;
+    if( tmout ){
+      res = walEnableBlockingMs(pWal, tmout);
+    }
+  }
+  return res;
+}
+
+/*
+** Disable blocking locks.
+*/
+static void walDisableBlocking(Wal *pWal){
+  int tmout = 0;
+  sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_LOCK_TIMEOUT, (void*)&tmout);
+}
+
+/*
+** If parameter bLock is true, attempt to enable blocking locks, take
+** the WRITER lock, and then disable blocking locks. If blocking locks
+** cannot be enabled, no attempt to obtain the WRITER lock is made. Return
+** an SQLite error code if an error occurs, or SQLITE_OK otherwise. It is not
+** an error if blocking locks can not be enabled.
+**
+** If the bLock parameter is false and the WRITER lock is held, release it.
+*/
+SQLITE_PRIVATE int sqlite3WalWriteLock(Wal *pWal, int bLock){
+  int rc = SQLITE_OK;
+  assert( pWal->readLock<0 || bLock==0 );
+  if( bLock ){
+    assert( pWal->db );
+    if( walEnableBlocking(pWal) ){
+      rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1);
+      if( rc==SQLITE_OK ){
+        pWal->writeLock = 1;
+      }
+      walDisableBlocking(pWal);
+    }
+  }else if( pWal->writeLock ){
+    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+    pWal->writeLock = 0;
+  }
+  return rc;
+}
+
+/*
+** Set the database handle used to determine if blocking locks are required.
+*/
+SQLITE_PRIVATE void sqlite3WalDb(Wal *pWal, sqlite3 *db){
+  pWal->db = db;
+}
+
+#else
+# define walEnableBlocking(x) 0
+# define walDisableBlocking(x)
+# define walEnableBlockingMs(pWal, ms) 0
+# define sqlite3WalDb(pWal, db)
+#endif   /* ifdef SQLITE_ENABLE_SETLK_TIMEOUT */
+
+
+/*
+** Attempt to obtain the exclusive WAL lock defined by parameters lockIdx and
+** n. If the attempt fails and parameter xBusy is not NULL, then it is a
+** busy-handler function. Invoke it and retry the lock until either the
+** lock is successfully obtained or the busy-handler returns 0.
+*/
+static int walBusyLock(
+  Wal *pWal,                      /* WAL connection */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int lockIdx,                    /* Offset of first byte to lock */
+  int n                           /* Number of bytes to lock */
+){
+  int rc;
+  do {
+    rc = walLockExclusive(pWal, lockIdx, n);
+  }while( xBusy && rc==SQLITE_BUSY && xBusy(pBusyArg) );
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  if( rc==SQLITE_BUSY_TIMEOUT ){
+    walDisableBlocking(pWal);
+    rc = SQLITE_BUSY;
+  }
+#endif
+  return rc;
+}
+
+/*
+** The cache of the wal-index header must be valid to call this function.
+** Return the page-size in bytes used by the database.
+*/
+static int walPagesize(Wal *pWal){
+  return (pWal->hdr.szPage&0xfe00) + ((pWal->hdr.szPage&0x0001)<<16);
+}
+
+/*
+** The following is guaranteed when this function is called:
+**
+**   a) the WRITER lock is held,
+**   b) the entire log file has been checkpointed, and
+**   c) any existing readers are reading exclusively from the database
+**      file - there are no readers that may attempt to read a frame from
+**      the log file.
+**
+** This function updates the shared-memory structures so that the next
+** client to write to the database (which may be this one) does so by
+** writing frames into the start of the log file.
+**
+** The value of parameter salt1 is used as the aSalt[1] value in the
+** new wal-index header. It should be passed a pseudo-random value (i.e.
+** one obtained from sqlite3_randomness()).
+*/
+static void walRestartHdr(Wal *pWal, u32 salt1){
+  volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
+  int i;                          /* Loop counter */
+  u32 *aSalt = pWal->hdr.aSalt;   /* Big-endian salt values */
+  pWal->nCkpt++;
+  pWal->hdr.mxFrame = 0;
+  sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
+  memcpy(&pWal->hdr.aSalt[1], &salt1, 4);
+  walIndexWriteHdr(pWal);
+  AtomicStore(&pInfo->nBackfill, 0);
+  pInfo->nBackfillAttempted = 0;
+  pInfo->aReadMark[1] = 0;
+  for(i=2; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
+  assert( pInfo->aReadMark[0]==0 );
+}
+
+/*
+** Copy as much content as we can from the WAL back into the database file
+** in response to an sqlite3_wal_checkpoint() request or the equivalent.
+**
+** The amount of information copies from WAL to database might be limited
+** by active readers.  This routine will never overwrite a database page
+** that a concurrent reader might be using.
+**
+** All I/O barrier operations (a.k.a fsyncs) occur in this routine when
+** SQLite is in WAL-mode in synchronous=NORMAL.  That means that if
+** checkpoints are always run by a background thread or background
+** process, foreground threads will never block on a lengthy fsync call.
+**
+** Fsync is called on the WAL before writing content out of the WAL and
+** into the database.  This ensures that if the new content is persistent
+** in the WAL and can be recovered following a power-loss or hard reset.
+**
+** Fsync is also called on the database file if (and only if) the entire
+** WAL content is copied into the database file.  This second fsync makes
+** it safe to delete the WAL since the new content will persist in the
+** database file.
+**
+** This routine uses and updates the nBackfill field of the wal-index header.
+** This is the only routine that will increase the value of nBackfill.
+** (A WAL reset or recovery will revert nBackfill to zero, but not increase
+** its value.)
+**
+** The caller must be holding sufficient locks to ensure that no other
+** checkpoint is running (in any other thread or process) at the same
+** time.
+*/
+static int walCheckpoint(
+  Wal *pWal,                      /* Wal connection */
+  sqlite3 *db,                    /* Check for interrupts on this handle */
+  int eMode,                      /* One of PASSIVE, FULL or RESTART */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags for OsSync() (or 0) */
+  u8 *zBuf                        /* Temporary buffer to use */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int szPage;                     /* Database page-size */
+  WalIterator *pIter = 0;         /* Wal iterator context */
+  u32 iDbpage = 0;                /* Next database page to write */
+  u32 iFrame = 0;                 /* Wal frame containing data for iDbpage */
+  u32 mxSafeFrame;                /* Max frame that can be backfilled */
+  u32 mxPage;                     /* Max database page to write */
+  int i;                          /* Loop counter */
+  volatile WalCkptInfo *pInfo;    /* The checkpoint status information */
+
+  szPage = walPagesize(pWal);
+  testcase( szPage<=32768 );
+  testcase( szPage>=65536 );
+  pInfo = walCkptInfo(pWal);
+  if( pInfo->nBackfill<pWal->hdr.mxFrame ){
+
+    /* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
+    ** in the SQLITE_CHECKPOINT_PASSIVE mode. */
+    assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );
+
+    /* Compute in mxSafeFrame the index of the last frame of the WAL that is
+    ** safe to write into the database.  Frames beyond mxSafeFrame might
+    ** overwrite database pages that are in use by active readers and thus
+    ** cannot be backfilled from the WAL.
+    */
+    mxSafeFrame = pWal->hdr.mxFrame;
+    mxPage = pWal->hdr.nPage;
+    for(i=1; i<WAL_NREADER; i++){
+      u32 y = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
+      if( mxSafeFrame>y ){
+        assert( y<=pWal->hdr.mxFrame );
+        rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
+        if( rc==SQLITE_OK ){
+          u32 iMark = (i==1 ? mxSafeFrame : READMARK_NOT_USED);
+          AtomicStore(pInfo->aReadMark+i, iMark); SEH_INJECT_FAULT;
+          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
+        }else if( rc==SQLITE_BUSY ){
+          mxSafeFrame = y;
+          xBusy = 0;
+        }else{
+          goto walcheckpoint_out;
+        }
+      }
+    }
+
+    /* Allocate the iterator */
+    if( pInfo->nBackfill<mxSafeFrame ){
+      rc = walIteratorInit(pWal, pInfo->nBackfill, &pIter);
+      assert( rc==SQLITE_OK || pIter==0 );
+    }
+
+    if( pIter
+     && (rc = walBusyLock(pWal,xBusy,pBusyArg,WAL_READ_LOCK(0),1))==SQLITE_OK
+    ){
+      u32 nBackfill = pInfo->nBackfill;
+      pInfo->nBackfillAttempted = mxSafeFrame; SEH_INJECT_FAULT;
+
+      /* Sync the WAL to disk */
+      rc = sqlite3OsSync(pWal->pWalFd, CKPT_SYNC_FLAGS(sync_flags));
+
+      /* If the database may grow as a result of this checkpoint, hint
+      ** about the eventual size of the db file to the VFS layer.
+      */
+      if( rc==SQLITE_OK ){
+        i64 nReq = ((i64)mxPage * szPage);
+        i64 nSize;                    /* Current size of database file */
+        sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_CKPT_START, 0);
+        rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
+        if( rc==SQLITE_OK && nSize<nReq ){
+          if( (nSize+65536+(i64)pWal->hdr.mxFrame*szPage)<nReq ){
+            /* If the size of the final database is larger than the current
+            ** database plus the amount of data in the wal file, plus the
+            ** maximum size of the pending-byte page (65536 bytes), then
+            ** must be corruption somewhere.  */
+            rc = SQLITE_CORRUPT_BKPT;
+          }else{
+            sqlite3OsFileControlHint(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT,&nReq);
+          }
+        }
+
+      }
+
+      /* Iterate through the contents of the WAL, copying data to the db file */
+      while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
+        i64 iOffset;
+        assert( walFramePgno(pWal, iFrame)==iDbpage );
+        SEH_INJECT_FAULT;
+        if( AtomicLoad(&db->u1.isInterrupted) ){
+          rc = db->mallocFailed ? SQLITE_NOMEM_BKPT : SQLITE_INTERRUPT;
+          break;
+        }
+        if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ){
+          continue;
+        }
+        iOffset = walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE;
+        /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL file */
+        rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, iOffset);
+        if( rc!=SQLITE_OK ) break;
+        iOffset = (iDbpage-1)*(i64)szPage;
+        testcase( IS_BIG_INT(iOffset) );
+        rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
+        if( rc!=SQLITE_OK ) break;
+      }
+      sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_CKPT_DONE, 0);
+
+      /* If work was actually accomplished... */
+      if( rc==SQLITE_OK ){
+        if( mxSafeFrame==walIndexHdr(pWal)->mxFrame ){
+          i64 szDb = pWal->hdr.nPage*(i64)szPage;
+          testcase( IS_BIG_INT(szDb) );
+          rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3OsSync(pWal->pDbFd, CKPT_SYNC_FLAGS(sync_flags));
+          }
+        }
+        if( rc==SQLITE_OK ){
+          AtomicStore(&pInfo->nBackfill, mxSafeFrame); SEH_INJECT_FAULT;
+        }
+      }
+
+      /* Release the reader lock held while backfilling */
+      walUnlockExclusive(pWal, WAL_READ_LOCK(0), 1);
+    }
+
+    if( rc==SQLITE_BUSY ){
+      /* Reset the return code so as not to report a checkpoint failure
+      ** just because there are active readers.  */
+      rc = SQLITE_OK;
+    }
+  }
+
+  /* If this is an SQLITE_CHECKPOINT_RESTART or TRUNCATE operation, and the
+  ** entire wal file has been copied into the database file, then block
+  ** until all readers have finished using the wal file. This ensures that
+  ** the next process to write to the database restarts the wal file.
+  */
+  if( rc==SQLITE_OK && eMode!=SQLITE_CHECKPOINT_PASSIVE ){
+    assert( pWal->writeLock );
+    SEH_INJECT_FAULT;
+    if( pInfo->nBackfill<pWal->hdr.mxFrame ){
+      rc = SQLITE_BUSY;
+    }else if( eMode>=SQLITE_CHECKPOINT_RESTART ){
+      u32 salt1;
+      sqlite3_randomness(4, &salt1);
+      assert( pInfo->nBackfill==pWal->hdr.mxFrame );
+      rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(1), WAL_NREADER-1);
+      if( rc==SQLITE_OK ){
+        if( eMode==SQLITE_CHECKPOINT_TRUNCATE ){
+          /* IMPLEMENTATION-OF: R-44699-57140 This mode works the same way as
+          ** SQLITE_CHECKPOINT_RESTART with the addition that it also
+          ** truncates the log file to zero bytes just prior to a
+          ** successful return.
+          **
+          ** In theory, it might be safe to do this without updating the
+          ** wal-index header in shared memory, as all subsequent reader or
+          ** writer clients should see that the entire log file has been
+          ** checkpointed and behave accordingly. This seems unsafe though,
+          ** as it would leave the system in a state where the contents of
+          ** the wal-index header do not match the contents of the
+          ** file-system. To avoid this, update the wal-index header to
+          ** indicate that the log file contains zero valid frames.  */
+          walRestartHdr(pWal, salt1);
+          rc = sqlite3OsTruncate(pWal->pWalFd, 0);
+        }
+        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
+      }
+    }
+  }
+
+ walcheckpoint_out:
+  SEH_FREE_ON_ERROR(pIter, 0);
+  walIteratorFree(pIter);
+  return rc;
+}
+
+/*
+** If the WAL file is currently larger than nMax bytes in size, truncate
+** it to exactly nMax bytes. If an error occurs while doing so, ignore it.
+*/
+static void walLimitSize(Wal *pWal, i64 nMax){
+  i64 sz;
+  int rx;
+  sqlite3BeginBenignMalloc();
+  rx = sqlite3OsFileSize(pWal->pWalFd, &sz);
+  if( rx==SQLITE_OK && (sz > nMax ) ){
+    rx = sqlite3OsTruncate(pWal->pWalFd, nMax);
+  }
+  sqlite3EndBenignMalloc();
+  if( rx ){
+    sqlite3_log(rx, "cannot limit WAL size: %s", pWal->zWalName);
+  }
+}
+
+#ifdef SQLITE_USE_SEH
+/*
+** This is the "standard" exception handler used in a few places to handle
+** an exception thrown by reading from the *-shm mapping after it has become
+** invalid in SQLITE_USE_SEH builds. It is used as follows:
+**
+**   SEH_TRY { ... }
+**   SEH_EXCEPT( rc = walHandleException(pWal); )
+**
+** This function does three things:
+**
+**   1) Determines the locks that should be held, based on the contents of
+**      the Wal.readLock, Wal.writeLock and Wal.ckptLock variables. All other
+**      held locks are assumed to be transient locks that would have been
+**      released had the exception not been thrown and are dropped.
+**
+**   2) Frees the pointer at Wal.pFree, if any, using sqlite3_free().
+**
+**   3) Set pWal->apWiData[pWal->iWiPg] to pWal->pWiValue if not NULL
+**
+**   4) Returns SQLITE_IOERR.
+*/
+static int walHandleException(Wal *pWal){
+  if( pWal->exclusiveMode==0 ){
+    static const int S = 1;
+    static const int E = (1<<SQLITE_SHM_NLOCK);
+    int ii;
+    u32 mUnlock = pWal->lockMask & ~(
+        (pWal->readLock<0 ? 0 : (S << WAL_READ_LOCK(pWal->readLock)))
+        | (pWal->writeLock ? (E << WAL_WRITE_LOCK) : 0)
+        | (pWal->ckptLock ? (E << WAL_CKPT_LOCK) : 0)
+        );
+    for(ii=0; ii<SQLITE_SHM_NLOCK; ii++){
+      if( (S<<ii) & mUnlock ) walUnlockShared(pWal, ii);
+      if( (E<<ii) & mUnlock ) walUnlockExclusive(pWal, ii, 1);
+    }
+  }
+  sqlite3_free(pWal->pFree);
+  pWal->pFree = 0;
+  if( pWal->pWiValue ){
+    pWal->apWiData[pWal->iWiPg] = pWal->pWiValue;
+    pWal->pWiValue = 0;
+  }
+  return SQLITE_IOERR_IN_PAGE;
+}
+
+/*
+** Assert that the Wal.lockMask mask, which indicates the locks held
+** by the connection, is consistent with the Wal.readLock, Wal.writeLock
+** and Wal.ckptLock variables. To be used as:
+**
+**   assert( walAssertLockmask(pWal) );
+*/
+static int walAssertLockmask(Wal *pWal){
+  if( pWal->exclusiveMode==0 ){
+    static const int S = 1;
+    static const int E = (1<<SQLITE_SHM_NLOCK);
+    u32 mExpect = (
+        (pWal->readLock<0 ? 0 : (S << WAL_READ_LOCK(pWal->readLock)))
+      | (pWal->writeLock ? (E << WAL_WRITE_LOCK) : 0)
+      | (pWal->ckptLock ? (E << WAL_CKPT_LOCK) : 0)
+#ifdef SQLITE_ENABLE_SNAPSHOT
+      | (pWal->pSnapshot ? (pWal->lockMask & (1 << WAL_CKPT_LOCK)) : 0)
+#endif
+    );
+    assert( mExpect==pWal->lockMask );
+  }
+  return 1;
+}
+
+/*
+** Return and zero the "system error" field set when an
+** EXCEPTION_IN_PAGE_ERROR exception is caught.
+*/
+SQLITE_PRIVATE int sqlite3WalSystemErrno(Wal *pWal){
+  int iRet = 0;
+  if( pWal ){
+    iRet = pWal->iSysErrno;
+    pWal->iSysErrno = 0;
+  }
+  return iRet;
+}
+
+#else
+# define walAssertLockmask(x) 1
+#endif /* ifdef SQLITE_USE_SEH */
+
+/*
+** Close a connection to a log file.
+*/
+SQLITE_PRIVATE int sqlite3WalClose(
+  Wal *pWal,                      /* Wal to close */
+  sqlite3 *db,                    /* For interrupt flag */
+  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */
+  int nBuf,
+  u8 *zBuf                        /* Buffer of at least nBuf bytes */
+){
+  int rc = SQLITE_OK;
+  if( pWal ){
+    int isDelete = 0;             /* True to unlink wal and wal-index files */
+
+    assert( walAssertLockmask(pWal) );
+
+    /* If an EXCLUSIVE lock can be obtained on the database file (using the
+    ** ordinary, rollback-mode locking methods, this guarantees that the
+    ** connection associated with this log file is the only connection to
+    ** the database. In this case checkpoint the database and unlink both
+    ** the wal and wal-index files.
+    **
+    ** The EXCLUSIVE lock is not released before returning.
+    */
+    if( zBuf!=0
+     && SQLITE_OK==(rc = sqlite3OsLock(pWal->pDbFd, SQLITE_LOCK_EXCLUSIVE))
+    ){
+      if( pWal->exclusiveMode==WAL_NORMAL_MODE ){
+        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
+      }
+      rc = sqlite3WalCheckpoint(pWal, db,
+          SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
+      );
+      if( rc==SQLITE_OK ){
+        int bPersist = -1;
+        sqlite3OsFileControlHint(
+            pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist
+        );
+        if( bPersist!=1 ){
+          /* Try to delete the WAL file if the checkpoint completed and
+          ** fsynced (rc==SQLITE_OK) and if we are not in persistent-wal
+          ** mode (!bPersist) */
+          isDelete = 1;
+        }else if( pWal->mxWalSize>=0 ){
+          /* Try to truncate the WAL file to zero bytes if the checkpoint
+          ** completed and fsynced (rc==SQLITE_OK) and we are in persistent
+          ** WAL mode (bPersist) and if the PRAGMA journal_size_limit is a
+          ** non-negative value (pWal->mxWalSize>=0).  Note that we truncate
+          ** to zero bytes as truncating to the journal_size_limit might
+          ** leave a corrupt WAL file on disk. */
+          walLimitSize(pWal, 0);
+        }
+      }
+    }
+
+    walIndexClose(pWal, isDelete);
+    sqlite3OsClose(pWal->pWalFd);
+    if( isDelete ){
+      sqlite3BeginBenignMalloc();
+      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
+      sqlite3EndBenignMalloc();
+    }
+    WALTRACE(("WAL%p: closed\n", pWal));
+    sqlite3_free((void *)pWal->apWiData);
+    sqlite3_free(pWal);
+  }
+  return rc;
+}
+
+/*
+** Try to read the wal-index header.  Return 0 on success and 1 if
+** there is a problem.
+**
+** The wal-index is in shared memory.  Another thread or process might
+** be writing the header at the same time this procedure is trying to
+** read it, which might result in inconsistency.  A dirty read is detected
+** by verifying that both copies of the header are the same and also by
+** a checksum on the header.
+**
+** If and only if the read is consistent and the header is different from
+** pWal->hdr, then pWal->hdr is updated to the content of the new header
+** and *pChanged is set to 1.
+**
+** If the checksum cannot be verified return non-zero. If the header
+** is read successfully and the checksum verified, return zero.
+*/
+static SQLITE_NO_TSAN int walIndexTryHdr(Wal *pWal, int *pChanged){
+  u32 aCksum[2];                  /* Checksum on the header content */
+  WalIndexHdr h1, h2;             /* Two copies of the header content */
+  WalIndexHdr volatile *aHdr;     /* Header in shared memory */
+
+  /* The first page of the wal-index must be mapped at this point. */
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+
+  /* Read the header. This might happen concurrently with a write to the
+  ** same area of shared memory on a different CPU in a SMP,
+  ** meaning it is possible that an inconsistent snapshot is read
+  ** from the file. If this happens, return non-zero.
+  **
+  ** tag-20200519-1:
+  ** There are two copies of the header at the beginning of the wal-index.
+  ** When reading, read [0] first then [1].  Writes are in the reverse order.
+  ** Memory barriers are used to prevent the compiler or the hardware from
+  ** reordering the reads and writes.  TSAN and similar tools can sometimes
+  ** give false-positive warnings about these accesses because the tools do not
+  ** account for the double-read and the memory barrier. The use of mutexes
+  ** here would be problematic as the memory being accessed is potentially
+  ** shared among multiple processes and not all mutex implementations work
+  ** reliably in that environment.
+  */
+  aHdr = walIndexHdr(pWal);
+  memcpy(&h1, (void *)&aHdr[0], sizeof(h1)); /* Possible TSAN false-positive */
+  walShmBarrier(pWal);
+  memcpy(&h2, (void *)&aHdr[1], sizeof(h2));
+
+  if( memcmp(&h1, &h2, sizeof(h1))!=0 ){
+    return 1;   /* Dirty read */
+  }
+  if( h1.isInit==0 ){
+    return 1;   /* Malformed header - probably all zeros */
+  }
+  walChecksumBytes(1, (u8*)&h1, sizeof(h1)-sizeof(h1.aCksum), 0, aCksum);
+  if( aCksum[0]!=h1.aCksum[0] || aCksum[1]!=h1.aCksum[1] ){
+    return 1;   /* Checksum does not match */
+  }
+
+  if( memcmp(&pWal->hdr, &h1, sizeof(WalIndexHdr)) ){
+    *pChanged = 1;
+    memcpy(&pWal->hdr, &h1, sizeof(WalIndexHdr));
+    pWal->szPage = (pWal->hdr.szPage&0xfe00) + ((pWal->hdr.szPage&0x0001)<<16);
+    testcase( pWal->szPage<=32768 );
+    testcase( pWal->szPage>=65536 );
+  }
+
+  /* The header was successfully read. Return zero. */
+  return 0;
+}
+
+/*
+** This is the value that walTryBeginRead returns when it needs to
+** be retried.
+*/
+#define WAL_RETRY  (-1)
+
+/*
+** Read the wal-index header from the wal-index and into pWal->hdr.
+** If the wal-header appears to be corrupt, try to reconstruct the
+** wal-index from the WAL before returning.
+**
+** Set *pChanged to 1 if the wal-index header value in pWal->hdr is
+** changed by this operation.  If pWal->hdr is unchanged, set *pChanged
+** to 0.
+**
+** If the wal-index header is successfully read, return SQLITE_OK.
+** Otherwise an SQLite error code.
+*/
+static int walIndexReadHdr(Wal *pWal, int *pChanged){
+  int rc;                         /* Return code */
+  int badHdr;                     /* True if a header read failed */
+  volatile u32 *page0;            /* Chunk of wal-index containing header */
+
+  /* Ensure that page 0 of the wal-index (the page that contains the
+  ** wal-index header) is mapped. Return early if an error occurs here.
+  */
+  assert( pChanged );
+  rc = walIndexPage(pWal, 0, &page0);
+  if( rc!=SQLITE_OK ){
+    assert( rc!=SQLITE_READONLY ); /* READONLY changed to OK in walIndexPage */
+    if( rc==SQLITE_READONLY_CANTINIT ){
+      /* The SQLITE_READONLY_CANTINIT return means that the shared-memory
+      ** was openable but is not writable, and this thread is unable to
+      ** confirm that another write-capable connection has the shared-memory
+      ** open, and hence the content of the shared-memory is unreliable,
+      ** since the shared-memory might be inconsistent with the WAL file
+      ** and there is no writer on hand to fix it. */
+      assert( page0==0 );
+      assert( pWal->writeLock==0 );
+      assert( pWal->readOnly & WAL_SHM_RDONLY );
+      pWal->bShmUnreliable = 1;
+      pWal->exclusiveMode = WAL_HEAPMEMORY_MODE;
+      *pChanged = 1;
+    }else{
+      return rc; /* Any other non-OK return is just an error */
+    }
+  }else{
+    /* page0 can be NULL if the SHM is zero bytes in size and pWal->writeLock
+    ** is zero, which prevents the SHM from growing */
+    testcase( page0!=0 );
+  }
+  assert( page0!=0 || pWal->writeLock==0 );
+
+  /* If the first page of the wal-index has been mapped, try to read the
+  ** wal-index header immediately, without holding any lock. This usually
+  ** works, but may fail if the wal-index header is corrupt or currently
+  ** being modified by another thread or process.
+  */
+  badHdr = (page0 ? walIndexTryHdr(pWal, pChanged) : 1);
+
+  /* If the first attempt failed, it might have been due to a race
+  ** with a writer.  So get a WRITE lock and try again.
+  */
+  if( badHdr ){
+    if( pWal->bShmUnreliable==0 && (pWal->readOnly & WAL_SHM_RDONLY) ){
+      if( SQLITE_OK==(rc = walLockShared(pWal, WAL_WRITE_LOCK)) ){
+        walUnlockShared(pWal, WAL_WRITE_LOCK);
+        rc = SQLITE_READONLY_RECOVERY;
+      }
+    }else{
+      int bWriteLock = pWal->writeLock;
+      if( bWriteLock
+       || SQLITE_OK==(rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1))
+      ){
+        pWal->writeLock = 1;
+        if( SQLITE_OK==(rc = walIndexPage(pWal, 0, &page0)) ){
+          badHdr = walIndexTryHdr(pWal, pChanged);
+          if( badHdr ){
+            /* If the wal-index header is still malformed even while holding
+            ** a WRITE lock, it can only mean that the header is corrupted and
+            ** needs to be reconstructed.  So run recovery to do exactly that.
+            ** Disable blocking locks first.  */
+            walDisableBlocking(pWal);
+            rc = walIndexRecover(pWal);
+            *pChanged = 1;
+          }
+        }
+        if( bWriteLock==0 ){
+          pWal->writeLock = 0;
+          walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+        }
+      }
+    }
+  }
+
+  /* If the header is read successfully, check the version number to make
+  ** sure the wal-index was not constructed with some future format that
+  ** this version of SQLite cannot understand.
+  */
+  if( badHdr==0 && pWal->hdr.iVersion!=WALINDEX_MAX_VERSION ){
+    rc = SQLITE_CANTOPEN_BKPT;
+  }
+  if( pWal->bShmUnreliable ){
+    if( rc!=SQLITE_OK ){
+      walIndexClose(pWal, 0);
+      pWal->bShmUnreliable = 0;
+      assert( pWal->nWiData>0 && pWal->apWiData[0]==0 );
+      /* walIndexRecover() might have returned SHORT_READ if a concurrent
+      ** writer truncated the WAL out from under it.  If that happens, it
+      ** indicates that a writer has fixed the SHM file for us, so retry */
+      if( rc==SQLITE_IOERR_SHORT_READ ) rc = WAL_RETRY;
+    }
+    pWal->exclusiveMode = WAL_NORMAL_MODE;
+  }
+
+  return rc;
+}
+
+/*
+** Open a transaction in a connection where the shared-memory is read-only
+** and where we cannot verify that there is a separate write-capable connection
+** on hand to keep the shared-memory up-to-date with the WAL file.
+**
+** This can happen, for example, when the shared-memory is implemented by
+** memory-mapping a *-shm file, where a prior writer has shut down and
+** left the *-shm file on disk, and now the present connection is trying
+** to use that database but lacks write permission on the *-shm file.
+** Other scenarios are also possible, depending on the VFS implementation.
+**
+** Precondition:
+**
+**    The *-wal file has been read and an appropriate wal-index has been
+**    constructed in pWal->apWiData[] using heap memory instead of shared
+**    memory.
+**
+** If this function returns SQLITE_OK, then the read transaction has
+** been successfully opened. In this case output variable (*pChanged)
+** is set to true before returning if the caller should discard the
+** contents of the page cache before proceeding. Or, if it returns
+** WAL_RETRY, then the heap memory wal-index has been discarded and
+** the caller should retry opening the read transaction from the
+** beginning (including attempting to map the *-shm file).
+**
+** If an error occurs, an SQLite error code is returned.
+*/
+static int walBeginShmUnreliable(Wal *pWal, int *pChanged){
+  i64 szWal;                      /* Size of wal file on disk in bytes */
+  i64 iOffset;                    /* Current offset when reading wal file */
+  u8 aBuf[WAL_HDRSIZE];           /* Buffer to load WAL header into */
+  u8 *aFrame = 0;                 /* Malloc'd buffer to load entire frame */
+  int szFrame;                    /* Number of bytes in buffer aFrame[] */
+  u8 *aData;                      /* Pointer to data part of aFrame buffer */
+  volatile void *pDummy;          /* Dummy argument for xShmMap */
+  int rc;                         /* Return code */
+  u32 aSaveCksum[2];              /* Saved copy of pWal->hdr.aFrameCksum */
+
+  assert( pWal->bShmUnreliable );
+  assert( pWal->readOnly & WAL_SHM_RDONLY );
+  assert( pWal->nWiData>0 && pWal->apWiData[0] );
+
+  /* Take WAL_READ_LOCK(0). This has the effect of preventing any
+  ** writers from running a checkpoint, but does not stop them
+  ** from running recovery.  */
+  rc = walLockShared(pWal, WAL_READ_LOCK(0));
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_BUSY ) rc = WAL_RETRY;
+    goto begin_unreliable_shm_out;
+  }
+  pWal->readLock = 0;
+
+  /* Check to see if a separate writer has attached to the shared-memory area,
+  ** thus making the shared-memory "reliable" again.  Do this by invoking
+  ** the xShmMap() routine of the VFS and looking to see if the return
+  ** is SQLITE_READONLY instead of SQLITE_READONLY_CANTINIT.
+  **
+  ** If the shared-memory is now "reliable" return WAL_RETRY, which will
+  ** cause the heap-memory WAL-index to be discarded and the actual
+  ** shared memory to be used in its place.
+  **
+  ** This step is important because, even though this connection is holding
+  ** the WAL_READ_LOCK(0) which prevents a checkpoint, a writer might
+  ** have already checkpointed the WAL file and, while the current
+  ** is active, wrap the WAL and start overwriting frames that this
+  ** process wants to use.
+  **
+  ** Once sqlite3OsShmMap() has been called for an sqlite3_file and has
+  ** returned any SQLITE_READONLY value, it must return only SQLITE_READONLY
+  ** or SQLITE_READONLY_CANTINIT or some error for all subsequent invocations,
+  ** even if some external agent does a "chmod" to make the shared-memory
+  ** writable by us, until sqlite3OsShmUnmap() has been called.
+  ** This is a requirement on the VFS implementation.
+   */
+  rc = sqlite3OsShmMap(pWal->pDbFd, 0, WALINDEX_PGSZ, 0, &pDummy);
+  assert( rc!=SQLITE_OK ); /* SQLITE_OK not possible for read-only connection */
+  if( rc!=SQLITE_READONLY_CANTINIT ){
+    rc = (rc==SQLITE_READONLY ? WAL_RETRY : rc);
+    goto begin_unreliable_shm_out;
+  }
+
+  /* We reach this point only if the real shared-memory is still unreliable.
+  ** Assume the in-memory WAL-index substitute is correct and load it
+  ** into pWal->hdr.
+  */
+  memcpy(&pWal->hdr, (void*)walIndexHdr(pWal), sizeof(WalIndexHdr));
+
+  /* Make sure some writer hasn't come in and changed the WAL file out
+  ** from under us, then disconnected, while we were not looking.
+  */
+  rc = sqlite3OsFileSize(pWal->pWalFd, &szWal);
+  if( rc!=SQLITE_OK ){
+    goto begin_unreliable_shm_out;
+  }
+  if( szWal<WAL_HDRSIZE ){
+    /* If the wal file is too small to contain a wal-header and the
+    ** wal-index header has mxFrame==0, then it must be safe to proceed
+    ** reading the database file only. However, the page cache cannot
+    ** be trusted, as a read/write connection may have connected, written
+    ** the db, run a checkpoint, truncated the wal file and disconnected
+    ** since this client's last read transaction.  */
+    *pChanged = 1;
+    rc = (pWal->hdr.mxFrame==0 ? SQLITE_OK : WAL_RETRY);
+    goto begin_unreliable_shm_out;
+  }
+
+  /* Check the salt keys at the start of the wal file still match. */
+  rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
+  if( rc!=SQLITE_OK ){
+    goto begin_unreliable_shm_out;
+  }
+  if( memcmp(&pWal->hdr.aSalt, &aBuf[16], 8) ){
+    /* Some writer has wrapped the WAL file while we were not looking.
+    ** Return WAL_RETRY which will cause the in-memory WAL-index to be
+    ** rebuilt. */
+    rc = WAL_RETRY;
+    goto begin_unreliable_shm_out;
+  }
+
+  /* Allocate a buffer to read frames into */
+  assert( (pWal->szPage & (pWal->szPage-1))==0 );
+  assert( pWal->szPage>=512 && pWal->szPage<=65536 );
+  szFrame = pWal->szPage + WAL_FRAME_HDRSIZE;
+  aFrame = (u8 *)sqlite3_malloc64(szFrame);
+  if( aFrame==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto begin_unreliable_shm_out;
+  }
+  aData = &aFrame[WAL_FRAME_HDRSIZE];
+
+  /* Check to see if a complete transaction has been appended to the
+  ** wal file since the heap-memory wal-index was created. If so, the
+  ** heap-memory wal-index is discarded and WAL_RETRY returned to
+  ** the caller.  */
+  aSaveCksum[0] = pWal->hdr.aFrameCksum[0];
+  aSaveCksum[1] = pWal->hdr.aFrameCksum[1];
+  for(iOffset=walFrameOffset(pWal->hdr.mxFrame+1, pWal->szPage);
+      iOffset+szFrame<=szWal;
+      iOffset+=szFrame
+  ){
+    u32 pgno;                   /* Database page number for frame */
+    u32 nTruncate;              /* dbsize field from frame header */
+
+    /* Read and decode the next log frame. */
+    rc = sqlite3OsRead(pWal->pWalFd, aFrame, szFrame, iOffset);
+    if( rc!=SQLITE_OK ) break;
+    if( !walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame) ) break;
+
+    /* If nTruncate is non-zero, then a complete transaction has been
+    ** appended to this wal file. Set rc to WAL_RETRY and break out of
+    ** the loop.  */
+    if( nTruncate ){
+      rc = WAL_RETRY;
+      break;
+    }
+  }
+  pWal->hdr.aFrameCksum[0] = aSaveCksum[0];
+  pWal->hdr.aFrameCksum[1] = aSaveCksum[1];
+
+ begin_unreliable_shm_out:
+  sqlite3_free(aFrame);
+  if( rc!=SQLITE_OK ){
+    int i;
+    for(i=0; i<pWal->nWiData; i++){
+      sqlite3_free((void*)pWal->apWiData[i]);
+      pWal->apWiData[i] = 0;
+    }
+    pWal->bShmUnreliable = 0;
+    sqlite3WalEndReadTransaction(pWal);
+    *pChanged = 1;
+  }
+  return rc;
+}
+
+/*
+** The final argument passed to walTryBeginRead() is of type (int*). The
+** caller should invoke walTryBeginRead as follows:
+**
+**   int cnt = 0;
+**   do {
+**     rc = walTryBeginRead(..., &cnt);
+**   }while( rc==WAL_RETRY );
+**
+** The final value of "cnt" is of no use to the caller. It is used by
+** the implementation of walTryBeginRead() as follows:
+**
+**   + Each time walTryBeginRead() is called, it is incremented. Once
+**     it reaches WAL_RETRY_PROTOCOL_LIMIT - indicating that walTryBeginRead()
+**     has many times been invoked and failed with WAL_RETRY - walTryBeginRead()
+**     returns SQLITE_PROTOCOL.
+**
+**   + If SQLITE_ENABLE_SETLK_TIMEOUT is defined and walTryBeginRead() failed
+**     because a blocking lock timed out (SQLITE_BUSY_TIMEOUT from the OS
+**     layer), the WAL_RETRY_BLOCKED_MASK bit is set in "cnt". In this case
+**     the next invocation of walTryBeginRead() may omit an expected call to
+**     sqlite3OsSleep(). There has already been a delay when the previous call
+**     waited on a lock.
+*/
+#define WAL_RETRY_PROTOCOL_LIMIT 100
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+# define WAL_RETRY_BLOCKED_MASK    0x10000000
+#else
+# define WAL_RETRY_BLOCKED_MASK    0
+#endif
+
+/*
+** Attempt to start a read transaction.  This might fail due to a race or
+** other transient condition.  When that happens, it returns WAL_RETRY to
+** indicate to the caller that it is safe to retry immediately.
+**
+** On success return SQLITE_OK.  On a permanent failure (such an
+** I/O error or an SQLITE_BUSY because another process is running
+** recovery) return a positive error code.
+**
+** The useWal parameter is true to force the use of the WAL and disable
+** the case where the WAL is bypassed because it has been completely
+** checkpointed.  If useWal==0 then this routine calls walIndexReadHdr()
+** to make a copy of the wal-index header into pWal->hdr.  If the
+** wal-index header has changed, *pChanged is set to 1 (as an indication
+** to the caller that the local page cache is obsolete and needs to be
+** flushed.)  When useWal==1, the wal-index header is assumed to already
+** be loaded and the pChanged parameter is unused.
+**
+** The caller must set the cnt parameter to the number of prior calls to
+** this routine during the current read attempt that returned WAL_RETRY.
+** This routine will start taking more aggressive measures to clear the
+** race conditions after multiple WAL_RETRY returns, and after an excessive
+** number of errors will ultimately return SQLITE_PROTOCOL.  The
+** SQLITE_PROTOCOL return indicates that some other process has gone rogue
+** and is not honoring the locking protocol.  There is a vanishingly small
+** chance that SQLITE_PROTOCOL could be returned because of a run of really
+** bad luck when there is lots of contention for the wal-index, but that
+** possibility is so small that it can be safely neglected, we believe.
+**
+** On success, this routine obtains a read lock on
+** WAL_READ_LOCK(pWal->readLock).  The pWal->readLock integer is
+** in the range 0 <= pWal->readLock < WAL_NREADER.  If pWal->readLock==(-1)
+** that means the Wal does not hold any read lock.  The reader must not
+** access any database page that is modified by a WAL frame up to and
+** including frame number aReadMark[pWal->readLock].  The reader will
+** use WAL frames up to and including pWal->hdr.mxFrame if pWal->readLock>0
+** Or if pWal->readLock==0, then the reader will ignore the WAL
+** completely and get all content directly from the database file.
+** If the useWal parameter is 1 then the WAL will never be ignored and
+** this routine will always set pWal->readLock>0 on success.
+** When the read transaction is completed, the caller must release the
+** lock on WAL_READ_LOCK(pWal->readLock) and set pWal->readLock to -1.
+**
+** This routine uses the nBackfill and aReadMark[] fields of the header
+** to select a particular WAL_READ_LOCK() that strives to let the
+** checkpoint process do as much work as possible.  This routine might
+** update values of the aReadMark[] array in the header, but if it does
+** so it takes care to hold an exclusive lock on the corresponding
+** WAL_READ_LOCK() while changing values.
+*/
+static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
+  volatile WalCkptInfo *pInfo;    /* Checkpoint information in wal-index */
+  int rc = SQLITE_OK;             /* Return code  */
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  int nBlockTmout = 0;
+#endif
+
+  assert( pWal->readLock<0 );     /* Not currently locked */
+
+  /* useWal may only be set for read/write connections */
+  assert( (pWal->readOnly & WAL_SHM_RDONLY)==0 || useWal==0 );
+
+  /* Take steps to avoid spinning forever if there is a protocol error.
+  **
+  ** Circumstances that cause a RETRY should only last for the briefest
+  ** instances of time.  No I/O or other system calls are done while the
+  ** locks are held, so the locks should not be held for very long. But
+  ** if we are unlucky, another process that is holding a lock might get
+  ** paged out or take a page-fault that is time-consuming to resolve,
+  ** during the few nanoseconds that it is holding the lock.  In that case,
+  ** it might take longer than normal for the lock to free.
+  **
+  ** After 5 RETRYs, we begin calling sqlite3OsSleep().  The first few
+  ** calls to sqlite3OsSleep() have a delay of 1 microsecond.  Really this
+  ** is more of a scheduler yield than an actual delay.  But on the 10th
+  ** an subsequent retries, the delays start becoming longer and longer,
+  ** so that on the 100th (and last) RETRY we delay for 323 milliseconds.
+  ** The total delay time before giving up is less than 10 seconds.
+  */
+  (*pCnt)++;
+  if( *pCnt>5 ){
+    int nDelay = 1;                      /* Pause time in microseconds */
+    int cnt = (*pCnt & ~WAL_RETRY_BLOCKED_MASK);
+    if( cnt>WAL_RETRY_PROTOCOL_LIMIT ){
+      VVA_ONLY( pWal->lockError = 1; )
+      return SQLITE_PROTOCOL;
+    }
+    if( *pCnt>=10 ) nDelay = (cnt-9)*(cnt-9)*39;
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    /* In SQLITE_ENABLE_SETLK_TIMEOUT builds, configure the file-descriptor
+    ** to block for locks for approximately nDelay us. This affects three
+    ** locks: (a) the shared lock taken on the DMS slot in os_unix.c (if
+    ** using os_unix.c), (b) the WRITER lock taken in walIndexReadHdr() if the
+    ** first attempted read fails, and (c) the shared lock taken on the
+    ** read-mark.
+    **
+    ** If the previous call failed due to an SQLITE_BUSY_TIMEOUT error,
+    ** then sleep for the minimum of 1us. The previous call already provided
+    ** an extra delay while it was blocking on the lock.
+    */
+    nBlockTmout = (nDelay+998) / 1000;
+    if( !useWal && walEnableBlockingMs(pWal, nBlockTmout) ){
+      if( *pCnt & WAL_RETRY_BLOCKED_MASK ) nDelay = 1;
+    }
+#endif
+    sqlite3OsSleep(pWal->pVfs, nDelay);
+    *pCnt &= ~WAL_RETRY_BLOCKED_MASK;
+  }
+
+  if( !useWal ){
+    assert( rc==SQLITE_OK );
+    if( pWal->bShmUnreliable==0 ){
+      rc = walIndexReadHdr(pWal, pChanged);
+    }
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    walDisableBlocking(pWal);
+    if( rc==SQLITE_BUSY_TIMEOUT ){
+      rc = SQLITE_BUSY;
+      *pCnt |= WAL_RETRY_BLOCKED_MASK;
+    }
+#endif
+    if( rc==SQLITE_BUSY ){
+      /* If there is not a recovery running in another thread or process
+      ** then convert BUSY errors to WAL_RETRY.  If recovery is known to
+      ** be running, convert BUSY to BUSY_RECOVERY.  There is a race here
+      ** which might cause WAL_RETRY to be returned even if BUSY_RECOVERY
+      ** would be technically correct.  But the race is benign since with
+      ** WAL_RETRY this routine will be called again and will probably be
+      ** right on the second iteration.
+      */
+      if( pWal->apWiData[0]==0 ){
+        /* This branch is taken when the xShmMap() method returns SQLITE_BUSY.
+        ** We assume this is a transient condition, so return WAL_RETRY. The
+        ** xShmMap() implementation used by the default unix and win32 VFS
+        ** modules may return SQLITE_BUSY due to a race condition in the
+        ** code that determines whether or not the shared-memory region
+        ** must be zeroed before the requested page is returned.
+        */
+        rc = WAL_RETRY;
+      }else if( SQLITE_OK==(rc = walLockShared(pWal, WAL_RECOVER_LOCK)) ){
+        walUnlockShared(pWal, WAL_RECOVER_LOCK);
+        rc = WAL_RETRY;
+      }else if( rc==SQLITE_BUSY ){
+        rc = SQLITE_BUSY_RECOVERY;
+      }
+    }
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    else if( pWal->bShmUnreliable ){
+      return walBeginShmUnreliable(pWal, pChanged);
+    }
+  }
+
+  assert( pWal->nWiData>0 );
+  assert( pWal->apWiData[0]!=0 );
+  pInfo = walCkptInfo(pWal);
+  SEH_INJECT_FAULT;
+  {
+    u32 mxReadMark;               /* Largest aReadMark[] value */
+    int mxI;                      /* Index of largest aReadMark[] value */
+    int i;                        /* Loop counter */
+    u32 mxFrame;                  /* Wal frame to lock to */
+    if( !useWal && AtomicLoad(&pInfo->nBackfill)==pWal->hdr.mxFrame
+#ifdef SQLITE_ENABLE_SNAPSHOT
+     && ((pWal->bGetSnapshot==0 && pWal->pSnapshot==0) || pWal->hdr.mxFrame==0)
+#endif
+    ){
+      /* The WAL has been completely backfilled (or it is empty).
+      ** and can be safely ignored.
+      */
+      rc = walLockShared(pWal, WAL_READ_LOCK(0));
+      walShmBarrier(pWal);
+      if( rc==SQLITE_OK ){
+        if( memcmp((void *)walIndexHdr(pWal), &pWal->hdr,sizeof(WalIndexHdr)) ){
+          /* It is not safe to allow the reader to continue here if frames
+          ** may have been appended to the log before READ_LOCK(0) was obtained.
+          ** When holding READ_LOCK(0), the reader ignores the entire log file,
+          ** which implies that the database file contains a trustworthy
+          ** snapshot. Since holding READ_LOCK(0) prevents a checkpoint from
+          ** happening, this is usually correct.
+          **
+          ** However, if frames have been appended to the log (or if the log
+          ** is wrapped and written for that matter) before the READ_LOCK(0)
+          ** is obtained, that is not necessarily true. A checkpointer may
+          ** have started to backfill the appended frames but crashed before
+          ** it finished. Leaving a corrupt image in the database file.
+          */
+          walUnlockShared(pWal, WAL_READ_LOCK(0));
+          return WAL_RETRY;
+        }
+        pWal->readLock = 0;
+        return SQLITE_OK;
+      }else if( rc!=SQLITE_BUSY ){
+        return rc;
+      }
+    }
+
+    /* If we get this far, it means that the reader will want to use
+    ** the WAL to get at content from recent commits.  The job now is
+    ** to select one of the aReadMark[] entries that is closest to
+    ** but not exceeding pWal->hdr.mxFrame and lock that entry.
+    */
+    mxReadMark = 0;
+    mxI = 0;
+    mxFrame = pWal->hdr.mxFrame;
+#ifdef SQLITE_ENABLE_SNAPSHOT
+    if( pWal->pSnapshot && pWal->pSnapshot->mxFrame<mxFrame ){
+      mxFrame = pWal->pSnapshot->mxFrame;
+    }
+#endif
+    for(i=1; i<WAL_NREADER; i++){
+      u32 thisMark = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
+      if( mxReadMark<=thisMark && thisMark<=mxFrame ){
+        assert( thisMark!=READMARK_NOT_USED );
+        mxReadMark = thisMark;
+        mxI = i;
+      }
+    }
+    if( (pWal->readOnly & WAL_SHM_RDONLY)==0
+     && (mxReadMark<mxFrame || mxI==0)
+    ){
+      for(i=1; i<WAL_NREADER; i++){
+        rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
+        if( rc==SQLITE_OK ){
+          AtomicStore(pInfo->aReadMark+i,mxFrame);
+          mxReadMark = mxFrame;
+          mxI = i;
+          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
+          break;
+        }else if( rc!=SQLITE_BUSY ){
+          return rc;
+        }
+      }
+    }
+    if( mxI==0 ){
+      assert( rc==SQLITE_BUSY || (pWal->readOnly & WAL_SHM_RDONLY)!=0 );
+      return rc==SQLITE_BUSY ? WAL_RETRY : SQLITE_READONLY_CANTINIT;
+    }
+
+    (void)walEnableBlockingMs(pWal, nBlockTmout);
+    rc = walLockShared(pWal, WAL_READ_LOCK(mxI));
+    walDisableBlocking(pWal);
+    if( rc ){
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+      if( rc==SQLITE_BUSY_TIMEOUT ){
+        *pCnt |= WAL_RETRY_BLOCKED_MASK;
+      }
+#else
+      assert( rc!=SQLITE_BUSY_TIMEOUT );
+#endif
+      assert((rc&0xFF)!=SQLITE_BUSY||rc==SQLITE_BUSY||rc==SQLITE_BUSY_TIMEOUT);
+      return (rc&0xFF)==SQLITE_BUSY ? WAL_RETRY : rc;
+    }
+    /* Now that the read-lock has been obtained, check that neither the
+    ** value in the aReadMark[] array or the contents of the wal-index
+    ** header have changed.
+    **
+    ** It is necessary to check that the wal-index header did not change
+    ** between the time it was read and when the shared-lock was obtained
+    ** on WAL_READ_LOCK(mxI) was obtained to account for the possibility
+    ** that the log file may have been wrapped by a writer, or that frames
+    ** that occur later in the log than pWal->hdr.mxFrame may have been
+    ** copied into the database by a checkpointer. If either of these things
+    ** happened, then reading the database with the current value of
+    ** pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry
+    ** instead.
+    **
+    ** Before checking that the live wal-index header has not changed
+    ** since it was read, set Wal.minFrame to the first frame in the wal
+    ** file that has not yet been checkpointed. This client will not need
+    ** to read any frames earlier than minFrame from the wal file - they
+    ** can be safely read directly from the database file.
+    **
+    ** Because a ShmBarrier() call is made between taking the copy of
+    ** nBackfill and checking that the wal-header in shared-memory still
+    ** matches the one cached in pWal->hdr, it is guaranteed that the
+    ** checkpointer that set nBackfill was not working with a wal-index
+    ** header newer than that cached in pWal->hdr. If it were, that could
+    ** cause a problem. The checkpointer could omit to checkpoint
+    ** a version of page X that lies before pWal->minFrame (call that version
+    ** A) on the basis that there is a newer version (version B) of the same
+    ** page later in the wal file. But if version B happens to like past
+    ** frame pWal->hdr.mxFrame - then the client would incorrectly assume
+    ** that it can read version A from the database file. However, since
+    ** we can guarantee that the checkpointer that set nBackfill could not
+    ** see any pages past pWal->hdr.mxFrame, this problem does not come up.
+    */
+    pWal->minFrame = AtomicLoad(&pInfo->nBackfill)+1; SEH_INJECT_FAULT;
+    walShmBarrier(pWal);
+    if( AtomicLoad(pInfo->aReadMark+mxI)!=mxReadMark
+     || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
+    ){
+      walUnlockShared(pWal, WAL_READ_LOCK(mxI));
+      return WAL_RETRY;
+    }else{
+      assert( mxReadMark<=pWal->hdr.mxFrame );
+      pWal->readLock = (i16)mxI;
+    }
+  }
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+/*
+** This function does the work of sqlite3WalSnapshotRecover().
+*/
+static int walSnapshotRecover(
+  Wal *pWal,                      /* WAL handle */
+  void *pBuf1,                    /* Temp buffer pWal->szPage bytes in size */
+  void *pBuf2                     /* Temp buffer pWal->szPage bytes in size */
+){
+  int szPage = (int)pWal->szPage;
+  int rc;
+  i64 szDb;                       /* Size of db file in bytes */
+
+  rc = sqlite3OsFileSize(pWal->pDbFd, &szDb);
+  if( rc==SQLITE_OK ){
+    volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
+    u32 i = pInfo->nBackfillAttempted;
+    for(i=pInfo->nBackfillAttempted; i>AtomicLoad(&pInfo->nBackfill); i--){
+      WalHashLoc sLoc;          /* Hash table location */
+      u32 pgno;                 /* Page number in db file */
+      i64 iDbOff;               /* Offset of db file entry */
+      i64 iWalOff;              /* Offset of wal file entry */
+
+      rc = walHashGet(pWal, walFramePage(i), &sLoc);
+      if( rc!=SQLITE_OK ) break;
+      assert( i - sLoc.iZero - 1 >=0 );
+      pgno = sLoc.aPgno[i-sLoc.iZero-1];
+      iDbOff = (i64)(pgno-1) * szPage;
+
+      if( iDbOff+szPage<=szDb ){
+        iWalOff = walFrameOffset(i, szPage) + WAL_FRAME_HDRSIZE;
+        rc = sqlite3OsRead(pWal->pWalFd, pBuf1, szPage, iWalOff);
+
+        if( rc==SQLITE_OK ){
+          rc = sqlite3OsRead(pWal->pDbFd, pBuf2, szPage, iDbOff);
+        }
+
+        if( rc!=SQLITE_OK || 0==memcmp(pBuf1, pBuf2, szPage) ){
+          break;
+        }
+      }
+
+      pInfo->nBackfillAttempted = i-1;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Attempt to reduce the value of the WalCkptInfo.nBackfillAttempted
+** variable so that older snapshots can be accessed. To do this, loop
+** through all wal frames from nBackfillAttempted to (nBackfill+1),
+** comparing their content to the corresponding page with the database
+** file, if any. Set nBackfillAttempted to the frame number of the
+** first frame for which the wal file content matches the db file.
+**
+** This is only really safe if the file-system is such that any page
+** writes made by earlier checkpointers were atomic operations, which
+** is not always true. It is also possible that nBackfillAttempted
+** may be left set to a value larger than expected, if a wal frame
+** contains content that duplicate of an earlier version of the same
+** page.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code if an
+** error occurs. It is not an error if nBackfillAttempted cannot be
+** decreased at all.
+*/
+SQLITE_PRIVATE int sqlite3WalSnapshotRecover(Wal *pWal){
+  int rc;
+
+  assert( pWal->readLock>=0 );
+  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
+  if( rc==SQLITE_OK ){
+    void *pBuf1 = sqlite3_malloc(pWal->szPage);
+    void *pBuf2 = sqlite3_malloc(pWal->szPage);
+    if( pBuf1==0 || pBuf2==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pWal->ckptLock = 1;
+      SEH_TRY {
+        rc = walSnapshotRecover(pWal, pBuf1, pBuf2);
+      }
+      SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+      pWal->ckptLock = 0;
+    }
+
+    sqlite3_free(pBuf1);
+    sqlite3_free(pBuf2);
+    walUnlockExclusive(pWal, WAL_CKPT_LOCK, 1);
+  }
+
+  return rc;
+}
+#endif /* SQLITE_ENABLE_SNAPSHOT */
+
+/*
+** This function does the work of sqlite3WalBeginReadTransaction() (see
+** below). That function simply calls this one inside an SEH_TRY{...} block.
+*/
+static int walBeginReadTransaction(Wal *pWal, int *pChanged){
+  int rc;                         /* Return code */
+  int cnt = 0;                    /* Number of TryBeginRead attempts */
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  int ckptLock = 0;
+  int bChanged = 0;
+  WalIndexHdr *pSnapshot = pWal->pSnapshot;
+#endif
+
+  assert( pWal->ckptLock==0 );
+  assert( pWal->nSehTry>0 );
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  if( pSnapshot ){
+    if( memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
+      bChanged = 1;
+    }
+
+    /* It is possible that there is a checkpointer thread running
+    ** concurrent with this code. If this is the case, it may be that the
+    ** checkpointer has already determined that it will checkpoint
+    ** snapshot X, where X is later in the wal file than pSnapshot, but
+    ** has not yet set the pInfo->nBackfillAttempted variable to indicate
+    ** its intent. To avoid the race condition this leads to, ensure that
+    ** there is no checkpointer process by taking a shared CKPT lock
+    ** before checking pInfo->nBackfillAttempted.  */
+    (void)walEnableBlocking(pWal);
+    rc = walLockShared(pWal, WAL_CKPT_LOCK);
+    walDisableBlocking(pWal);
+
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    ckptLock = 1;
+  }
+#endif
+
+  do{
+    rc = walTryBeginRead(pWal, pChanged, 0, &cnt);
+  }while( rc==WAL_RETRY );
+  testcase( (rc&0xff)==SQLITE_BUSY );
+  testcase( (rc&0xff)==SQLITE_IOERR );
+  testcase( rc==SQLITE_PROTOCOL );
+  testcase( rc==SQLITE_OK );
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+  if( rc==SQLITE_OK ){
+    if( pSnapshot && memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
+      /* At this point the client has a lock on an aReadMark[] slot holding
+      ** a value equal to or smaller than pSnapshot->mxFrame, but pWal->hdr
+      ** is populated with the wal-index header corresponding to the head
+      ** of the wal file. Verify that pSnapshot is still valid before
+      ** continuing.  Reasons why pSnapshot might no longer be valid:
+      **
+      **    (1)  The WAL file has been reset since the snapshot was taken.
+      **         In this case, the salt will have changed.
+      **
+      **    (2)  A checkpoint as been attempted that wrote frames past
+      **         pSnapshot->mxFrame into the database file.  Note that the
+      **         checkpoint need not have completed for this to cause problems.
+      */
+      volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
+
+      assert( pWal->readLock>0 || pWal->hdr.mxFrame==0 );
+      assert( pInfo->aReadMark[pWal->readLock]<=pSnapshot->mxFrame );
+
+      /* Check that the wal file has not been wrapped. Assuming that it has
+      ** not, also check that no checkpointer has attempted to checkpoint any
+      ** frames beyond pSnapshot->mxFrame. If either of these conditions are
+      ** true, return SQLITE_ERROR_SNAPSHOT. Otherwise, overwrite pWal->hdr
+      ** with *pSnapshot and set *pChanged as appropriate for opening the
+      ** snapshot.  */
+      if( !memcmp(pSnapshot->aSalt, pWal->hdr.aSalt, sizeof(pWal->hdr.aSalt))
+       && pSnapshot->mxFrame>=pInfo->nBackfillAttempted
+      ){
+        assert( pWal->readLock>0 );
+        memcpy(&pWal->hdr, pSnapshot, sizeof(WalIndexHdr));
+        *pChanged = bChanged;
+      }else{
+        rc = SQLITE_ERROR_SNAPSHOT;
+      }
+
+      /* A client using a non-current snapshot may not ignore any frames
+      ** from the start of the wal file. This is because, for a system
+      ** where (minFrame < iSnapshot < maxFrame), a checkpointer may
+      ** have omitted to checkpoint a frame earlier than minFrame in
+      ** the file because there exists a frame after iSnapshot that
+      ** is the same database page.  */
+      pWal->minFrame = 1;
+
+      if( rc!=SQLITE_OK ){
+        sqlite3WalEndReadTransaction(pWal);
+      }
+    }
+  }
+
+  /* Release the shared CKPT lock obtained above. */
+  if( ckptLock ){
+    assert( pSnapshot );
+    walUnlockShared(pWal, WAL_CKPT_LOCK);
+  }
+#endif
+  return rc;
+}
+
+/*
+** Begin a read transaction on the database.
+**
+** This routine used to be called sqlite3OpenSnapshot() and with good reason:
+** it takes a snapshot of the state of the WAL and wal-index for the current
+** instant in time.  The current thread will continue to use this snapshot.
+** Other threads might append new content to the WAL and wal-index but
+** that extra content is ignored by the current thread.
+**
+** If the database contents have changes since the previous read
+** transaction, then *pChanged is set to 1 before returning.  The
+** Pager layer will use this to know that its cache is stale and
+** needs to be flushed.
+*/
+SQLITE_PRIVATE int sqlite3WalBeginReadTransaction(Wal *pWal, int *pChanged){
+  int rc;
+  SEH_TRY {
+    rc = walBeginReadTransaction(pWal, pChanged);
+  }
+  SEH_EXCEPT( rc = walHandleException(pWal); )
+  return rc;
+}
+
+/*
+** Finish with a read transaction.  All this does is release the
+** read-lock.
+*/
+SQLITE_PRIVATE void sqlite3WalEndReadTransaction(Wal *pWal){
+  sqlite3WalEndWriteTransaction(pWal);
+  if( pWal->readLock>=0 ){
+    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
+    pWal->readLock = -1;
+  }
+}
+
+/*
+** Search the wal file for page pgno. If found, set *piRead to the frame that
+** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
+** to zero.
+**
+** Return SQLITE_OK if successful, or an error code if an error occurs. If an
+** error does occur, the final value of *piRead is undefined.
+*/
+static int walFindFrame(
+  Wal *pWal,                      /* WAL handle */
+  Pgno pgno,                      /* Database page number to read data for */
+  u32 *piRead                     /* OUT: Frame number (or zero) */
+){
+  u32 iRead = 0;                  /* If !=0, WAL frame to return data from */
+  u32 iLast = pWal->hdr.mxFrame;  /* Last page in WAL for this reader */
+  int iHash;                      /* Used to loop through N hash tables */
+  int iMinHash;
+
+  /* This routine is only be called from within a read transaction. */
+  assert( pWal->readLock>=0 || pWal->lockError );
+
+  /* If the "last page" field of the wal-index header snapshot is 0, then
+  ** no data will be read from the wal under any circumstances. Return early
+  ** in this case as an optimization.  Likewise, if pWal->readLock==0,
+  ** then the WAL is ignored by the reader so return early, as if the
+  ** WAL were empty.
+  */
+  if( iLast==0 || (pWal->readLock==0 && pWal->bShmUnreliable==0) ){
+    *piRead = 0;
+    return SQLITE_OK;
+  }
+
+  /* Search the hash table or tables for an entry matching page number
+  ** pgno. Each iteration of the following for() loop searches one
+  ** hash table (each hash table indexes up to HASHTABLE_NPAGE frames).
+  **
+  ** This code might run concurrently to the code in walIndexAppend()
+  ** that adds entries to the wal-index (and possibly to this hash
+  ** table). This means the value just read from the hash
+  ** slot (aHash[iKey]) may have been added before or after the
+  ** current read transaction was opened. Values added after the
+  ** read transaction was opened may have been written incorrectly -
+  ** i.e. these slots may contain garbage data. However, we assume
+  ** that any slots written before the current read transaction was
+  ** opened remain unmodified.
+  **
+  ** For the reasons above, the if(...) condition featured in the inner
+  ** loop of the following block is more stringent that would be required
+  ** if we had exclusive access to the hash-table:
+  **
+  **   (aPgno[iFrame]==pgno):
+  **     This condition filters out normal hash-table collisions.
+  **
+  **   (iFrame<=iLast):
+  **     This condition filters out entries that were added to the hash
+  **     table after the current read-transaction had started.
+  */
+  iMinHash = walFramePage(pWal->minFrame);
+  for(iHash=walFramePage(iLast); iHash>=iMinHash; iHash--){
+    WalHashLoc sLoc;              /* Hash table location */
+    int iKey;                     /* Hash slot index */
+    int nCollide;                 /* Number of hash collisions remaining */
+    int rc;                       /* Error code */
+    u32 iH;
+
+    rc = walHashGet(pWal, iHash, &sLoc);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    nCollide = HASHTABLE_NSLOT;
+    iKey = walHash(pgno);
+    SEH_INJECT_FAULT;
+    while( (iH = AtomicLoad(&sLoc.aHash[iKey]))!=0 ){
+      u32 iFrame = iH + sLoc.iZero;
+      if( iFrame<=iLast && iFrame>=pWal->minFrame && sLoc.aPgno[iH-1]==pgno ){
+        assert( iFrame>iRead || CORRUPT_DB );
+        iRead = iFrame;
+      }
+      if( (nCollide--)==0 ){
+        *piRead = 0;
+        return SQLITE_CORRUPT_BKPT;
+      }
+      iKey = walNextHash(iKey);
+    }
+    if( iRead ) break;
+  }
+
+#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
+  /* If expensive assert() statements are available, do a linear search
+  ** of the wal-index file content. Make sure the results agree with the
+  ** result obtained using the hash indexes above.  */
+  {
+    u32 iRead2 = 0;
+    u32 iTest;
+    assert( pWal->bShmUnreliable || pWal->minFrame>0 );
+    for(iTest=iLast; iTest>=pWal->minFrame && iTest>0; iTest--){
+      if( walFramePgno(pWal, iTest)==pgno ){
+        iRead2 = iTest;
+        break;
+      }
+    }
+    assert( iRead==iRead2 );
+  }
+#endif
+
+  *piRead = iRead;
+  return SQLITE_OK;
+}
+
+/*
+** Search the wal file for page pgno. If found, set *piRead to the frame that
+** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
+** to zero.
+**
+** Return SQLITE_OK if successful, or an error code if an error occurs. If an
+** error does occur, the final value of *piRead is undefined.
+**
+** The difference between this function and walFindFrame() is that this
+** function wraps walFindFrame() in an SEH_TRY{...} block.
+*/
+SQLITE_PRIVATE int sqlite3WalFindFrame(
+  Wal *pWal,                      /* WAL handle */
+  Pgno pgno,                      /* Database page number to read data for */
+  u32 *piRead                     /* OUT: Frame number (or zero) */
+){
+  int rc;
+  SEH_TRY {
+    rc = walFindFrame(pWal, pgno, piRead);
+  }
+  SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+  return rc;
+}
+
+/*
+** Read the contents of frame iRead from the wal file into buffer pOut
+** (which is nOut bytes in size). Return SQLITE_OK if successful, or an
+** error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3WalReadFrame(
+  Wal *pWal,                      /* WAL handle */
+  u32 iRead,                      /* Frame to read */
+  int nOut,                       /* Size of buffer pOut in bytes */
+  u8 *pOut                        /* Buffer to write page data to */
+){
+  int sz;
+  i64 iOffset;
+  sz = pWal->hdr.szPage;
+  sz = (sz&0xfe00) + ((sz&0x0001)<<16);
+  testcase( sz<=32768 );
+  testcase( sz>=65536 );
+  iOffset = walFrameOffset(iRead, sz) + WAL_FRAME_HDRSIZE;
+  /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
+  return sqlite3OsRead(pWal->pWalFd, pOut, (nOut>sz ? sz : nOut), iOffset);
+}
+
+/*
+** Return the size of the database in pages (or zero, if unknown).
+*/
+SQLITE_PRIVATE Pgno sqlite3WalDbsize(Wal *pWal){
+  if( pWal && ALWAYS(pWal->readLock>=0) ){
+    return pWal->hdr.nPage;
+  }
+  return 0;
+}
+
+
+/*
+** This function starts a write transaction on the WAL.
+**
+** A read transaction must have already been started by a prior call
+** to sqlite3WalBeginReadTransaction().
+**
+** If another thread or process has written into the database since
+** the read transaction was started, then it is not possible for this
+** thread to write as doing so would cause a fork.  So this routine
+** returns SQLITE_BUSY in that case and no write transaction is started.
+**
+** There can only be a single writer active at a time.
+*/
+SQLITE_PRIVATE int sqlite3WalBeginWriteTransaction(Wal *pWal){
+  int rc;
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  /* If the write-lock is already held, then it was obtained before the
+  ** read-transaction was even opened, making this call a no-op.
+  ** Return early. */
+  if( pWal->writeLock ){
+    assert( !memcmp(&pWal->hdr,(void *)walIndexHdr(pWal),sizeof(WalIndexHdr)) );
+    return SQLITE_OK;
+  }
+#endif
+
+  /* Cannot start a write transaction without first holding a read
+  ** transaction. */
+  assert( pWal->readLock>=0 );
+  assert( pWal->writeLock==0 && pWal->iReCksum==0 );
+
+  if( pWal->readOnly ){
+    return SQLITE_READONLY;
+  }
+
+  /* Only one writer allowed at a time.  Get the write lock.  Return
+  ** SQLITE_BUSY if unable.
+  */
+  rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1);
+  if( rc ){
+    return rc;
+  }
+  pWal->writeLock = 1;
+
+  /* If another connection has written to the database file since the
+  ** time the read transaction on this connection was started, then
+  ** the write is disallowed.
+  */
+  SEH_TRY {
+    if( memcmp(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr))!=0 ){
+      rc = SQLITE_BUSY_SNAPSHOT;
+    }
+  }
+  SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+
+  if( rc!=SQLITE_OK ){
+    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+    pWal->writeLock = 0;
+  }
+  return rc;
+}
+
+/*
+** End a write transaction.  The commit has already been done.  This
+** routine merely releases the lock.
+*/
+SQLITE_PRIVATE int sqlite3WalEndWriteTransaction(Wal *pWal){
+  if( pWal->writeLock ){
+    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
+    pWal->writeLock = 0;
+    pWal->iReCksum = 0;
+    pWal->truncateOnCommit = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** If any data has been written (but not committed) to the log file, this
+** function moves the write-pointer back to the start of the transaction.
+**
+** Additionally, the callback function is invoked for each frame written
+** to the WAL since the start of the transaction. If the callback returns
+** other than SQLITE_OK, it is not invoked again and the error code is
+** returned to the caller.
+**
+** Otherwise, if the callback function does not return an error, this
+** function returns SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
+  int rc = SQLITE_OK;
+  if( ALWAYS(pWal->writeLock) ){
+    Pgno iMax = pWal->hdr.mxFrame;
+    Pgno iFrame;
+
+    SEH_TRY {
+      /* Restore the clients cache of the wal-index header to the state it
+      ** was in before the client began writing to the database.
+      */
+      memcpy(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr));
+
+      for(iFrame=pWal->hdr.mxFrame+1;
+          ALWAYS(rc==SQLITE_OK) && iFrame<=iMax;
+          iFrame++
+      ){
+        /* This call cannot fail. Unless the page for which the page number
+        ** is passed as the second argument is (a) in the cache and
+        ** (b) has an outstanding reference, then xUndo is either a no-op
+        ** (if (a) is false) or simply expels the page from the cache (if (b)
+        ** is false).
+        **
+        ** If the upper layer is doing a rollback, it is guaranteed that there
+        ** are no outstanding references to any page other than page 1. And
+        ** page 1 is never written to the log until the transaction is
+        ** committed. As a result, the call to xUndo may not fail.
+        */
+        assert( walFramePgno(pWal, iFrame)!=1 );
+        rc = xUndo(pUndoCtx, walFramePgno(pWal, iFrame));
+      }
+      if( iMax!=pWal->hdr.mxFrame ) walCleanupHash(pWal);
+    }
+    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+  }
+  return rc;
+}
+
+/*
+** Argument aWalData must point to an array of WAL_SAVEPOINT_NDATA u32
+** values. This function populates the array with values required to
+** "rollback" the write position of the WAL handle back to the current
+** point in the event of a savepoint rollback (via WalSavepointUndo()).
+*/
+SQLITE_PRIVATE void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData){
+  assert( pWal->writeLock );
+  aWalData[0] = pWal->hdr.mxFrame;
+  aWalData[1] = pWal->hdr.aFrameCksum[0];
+  aWalData[2] = pWal->hdr.aFrameCksum[1];
+  aWalData[3] = pWal->nCkpt;
+}
+
+/*
+** Move the write position of the WAL back to the point identified by
+** the values in the aWalData[] array. aWalData must point to an array
+** of WAL_SAVEPOINT_NDATA u32 values that has been previously populated
+** by a call to WalSavepoint().
+*/
+SQLITE_PRIVATE int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData){
+  int rc = SQLITE_OK;
+
+  assert( pWal->writeLock );
+  assert( aWalData[3]!=pWal->nCkpt || aWalData[0]<=pWal->hdr.mxFrame );
+
+  if( aWalData[3]!=pWal->nCkpt ){
+    /* This savepoint was opened immediately after the write-transaction
+    ** was started. Right after that, the writer decided to wrap around
+    ** to the start of the log. Update the savepoint values to match.
+    */
+    aWalData[0] = 0;
+    aWalData[3] = pWal->nCkpt;
+  }
+
+  if( aWalData[0]<pWal->hdr.mxFrame ){
+    pWal->hdr.mxFrame = aWalData[0];
+    pWal->hdr.aFrameCksum[0] = aWalData[1];
+    pWal->hdr.aFrameCksum[1] = aWalData[2];
+    SEH_TRY {
+      walCleanupHash(pWal);
+    }
+    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
+  }
+
+  return rc;
+}
+
+/*
+** This function is called just before writing a set of frames to the log
+** file (see sqlite3WalFrames()). It checks to see if, instead of appending
+** to the current log file, it is possible to overwrite the start of the
+** existing log file with the new frames (i.e. "reset" the log). If so,
+** it sets pWal->hdr.mxFrame to 0. Otherwise, pWal->hdr.mxFrame is left
+** unchanged.
+**
+** SQLITE_OK is returned if no error is encountered (regardless of whether
+** or not pWal->hdr.mxFrame is modified). An SQLite error code is returned
+** if an error occurs.
+*/
+static int walRestartLog(Wal *pWal){
+  int rc = SQLITE_OK;
+  int cnt;
+
+  if( pWal->readLock==0 ){
+    volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
+    assert( pInfo->nBackfill==pWal->hdr.mxFrame );
+    if( pInfo->nBackfill>0 ){
+      u32 salt1;
+      sqlite3_randomness(4, &salt1);
+      rc = walLockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
+      if( rc==SQLITE_OK ){
+        /* If all readers are using WAL_READ_LOCK(0) (in other words if no
+        ** readers are currently using the WAL), then the transactions
+        ** frames will overwrite the start of the existing log. Update the
+        ** wal-index header to reflect this.
+        **
+        ** In theory it would be Ok to update the cache of the header only
+        ** at this point. But updating the actual wal-index header is also
+        ** safe and means there is no special case for sqlite3WalUndo()
+        ** to handle if this transaction is rolled back.  */
+        walRestartHdr(pWal, salt1);
+        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
+      }else if( rc!=SQLITE_BUSY ){
+        return rc;
+      }
+    }
+    walUnlockShared(pWal, WAL_READ_LOCK(0));
+    pWal->readLock = -1;
+    cnt = 0;
+    do{
+      int notUsed;
+      rc = walTryBeginRead(pWal, ¬Used, 1, &cnt);
+    }while( rc==WAL_RETRY );
+    assert( (rc&0xff)!=SQLITE_BUSY ); /* BUSY not possible when useWal==1 */
+    testcase( (rc&0xff)==SQLITE_IOERR );
+    testcase( rc==SQLITE_PROTOCOL );
+    testcase( rc==SQLITE_OK );
+  }
+  return rc;
+}
+
+/*
+** Information about the current state of the WAL file and where
+** the next fsync should occur - passed from sqlite3WalFrames() into
+** walWriteToLog().
+*/
+typedef struct WalWriter {
+  Wal *pWal;                   /* The complete WAL information */
+  sqlite3_file *pFd;           /* The WAL file to which we write */
+  sqlite3_int64 iSyncPoint;    /* Fsync at this offset */
+  int syncFlags;               /* Flags for the fsync */
+  int szPage;                  /* Size of one page */
+} WalWriter;
+
+/*
+** Write iAmt bytes of content into the WAL file beginning at iOffset.
+** Do a sync when crossing the p->iSyncPoint boundary.
+**
+** In other words, if iSyncPoint is in between iOffset and iOffset+iAmt,
+** first write the part before iSyncPoint, then sync, then write the
+** rest.
+*/
+static int walWriteToLog(
+  WalWriter *p,              /* WAL to write to */
+  void *pContent,            /* Content to be written */
+  int iAmt,                  /* Number of bytes to write */
+  sqlite3_int64 iOffset      /* Start writing at this offset */
+){
+  int rc;
+  if( iOffset<p->iSyncPoint && iOffset+iAmt>=p->iSyncPoint ){
+    int iFirstAmt = (int)(p->iSyncPoint - iOffset);
+    rc = sqlite3OsWrite(p->pFd, pContent, iFirstAmt, iOffset);
+    if( rc ) return rc;
+    iOffset += iFirstAmt;
+    iAmt -= iFirstAmt;
+    pContent = (void*)(iFirstAmt + (char*)pContent);
+    assert( WAL_SYNC_FLAGS(p->syncFlags)!=0 );
+    rc = sqlite3OsSync(p->pFd, WAL_SYNC_FLAGS(p->syncFlags));
+    if( iAmt==0 || rc ) return rc;
+  }
+  rc = sqlite3OsWrite(p->pFd, pContent, iAmt, iOffset);
+  return rc;
+}
+
+/*
+** Write out a single frame of the WAL
+*/
+static int walWriteOneFrame(
+  WalWriter *p,               /* Where to write the frame */
+  PgHdr *pPage,               /* The page of the frame to be written */
+  int nTruncate,              /* The commit flag.  Usually 0.  >0 for commit */
+  sqlite3_int64 iOffset       /* Byte offset at which to write */
+){
+  int rc;                         /* Result code from subfunctions */
+  void *pData;                    /* Data actually written */
+  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-header in */
+  pData = pPage->pData;
+  walEncodeFrame(p->pWal, pPage->pgno, nTruncate, pData, aFrame);
+  rc = walWriteToLog(p, aFrame, sizeof(aFrame), iOffset);
+  if( rc ) return rc;
+  /* Write the page data */
+  rc = walWriteToLog(p, pData, p->szPage, iOffset+sizeof(aFrame));
+  return rc;
+}
+
+/*
+** This function is called as part of committing a transaction within which
+** one or more frames have been overwritten. It updates the checksums for
+** all frames written to the wal file by the current transaction starting
+** with the earliest to have been overwritten.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+static int walRewriteChecksums(Wal *pWal, u32 iLast){
+  const int szPage = pWal->szPage;/* Database page size */
+  int rc = SQLITE_OK;             /* Return code */
+  u8 *aBuf;                       /* Buffer to load data from wal file into */
+  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-headers in */
+  u32 iRead;                      /* Next frame to read from wal file */
+  i64 iCksumOff;
+
+  aBuf = sqlite3_malloc(szPage + WAL_FRAME_HDRSIZE);
+  if( aBuf==0 ) return SQLITE_NOMEM_BKPT;
+
+  /* Find the checksum values to use as input for the recalculating the
+  ** first checksum. If the first frame is frame 1 (implying that the current
+  ** transaction restarted the wal file), these values must be read from the
+  ** wal-file header. Otherwise, read them from the frame header of the
+  ** previous frame.  */
+  assert( pWal->iReCksum>0 );
+  if( pWal->iReCksum==1 ){
+    iCksumOff = 24;
+  }else{
+    iCksumOff = walFrameOffset(pWal->iReCksum-1, szPage) + 16;
+  }
+  rc = sqlite3OsRead(pWal->pWalFd, aBuf, sizeof(u32)*2, iCksumOff);
+  pWal->hdr.aFrameCksum[0] = sqlite3Get4byte(aBuf);
+  pWal->hdr.aFrameCksum[1] = sqlite3Get4byte(&aBuf[sizeof(u32)]);
+
+  iRead = pWal->iReCksum;
+  pWal->iReCksum = 0;
+  for(; rc==SQLITE_OK && iRead<=iLast; iRead++){
+    i64 iOff = walFrameOffset(iRead, szPage);
+    rc = sqlite3OsRead(pWal->pWalFd, aBuf, szPage+WAL_FRAME_HDRSIZE, iOff);
+    if( rc==SQLITE_OK ){
+      u32 iPgno, nDbSize;
+      iPgno = sqlite3Get4byte(aBuf);
+      nDbSize = sqlite3Get4byte(&aBuf[4]);
+
+      walEncodeFrame(pWal, iPgno, nDbSize, &aBuf[WAL_FRAME_HDRSIZE], aFrame);
+      rc = sqlite3OsWrite(pWal->pWalFd, aFrame, sizeof(aFrame), iOff);
+    }
+  }
+
+  sqlite3_free(aBuf);
+  return rc;
+}
+
+/*
+** Write a set of frames to the log. The caller must hold the write-lock
+** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
+*/
+static int walFrames(
+  Wal *pWal,                      /* Wal handle to write to */
+  int szPage,                     /* Database page-size in bytes */
+  PgHdr *pList,                   /* List of dirty pages to write */
+  Pgno nTruncate,                 /* Database size after this commit */
+  int isCommit,                   /* True if this is a commit */
+  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
+){
+  int rc;                         /* Used to catch return codes */
+  u32 iFrame;                     /* Next frame address */
+  PgHdr *p;                       /* Iterator to run through pList with. */
+  PgHdr *pLast = 0;               /* Last frame in list */
+  int nExtra = 0;                 /* Number of extra copies of last page */
+  int szFrame;                    /* The size of a single frame */
+  i64 iOffset;                    /* Next byte to write in WAL file */
+  WalWriter w;                    /* The writer */
+  u32 iFirst = 0;                 /* First frame that may be overwritten */
+  WalIndexHdr *pLive;             /* Pointer to shared header */
+
+  assert( pList );
+  assert( pWal->writeLock );
+
+  /* If this frame set completes a transaction, then nTruncate>0.  If
+  ** nTruncate==0 then this frame set does not complete the transaction. */
+  assert( (isCommit!=0)==(nTruncate!=0) );
+
+#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
+  { int cnt; for(cnt=0, p=pList; p; p=p->pDirty, cnt++){}
+    WALTRACE(("WAL%p: frame write begin. %d frames. mxFrame=%d. %s\n",
+              pWal, cnt, pWal->hdr.mxFrame, isCommit ? "Commit" : "Spill"));
+  }
+#endif
+
+  pLive = (WalIndexHdr*)walIndexHdr(pWal);
+  if( memcmp(&pWal->hdr, (void *)pLive, sizeof(WalIndexHdr))!=0 ){
+    iFirst = pLive->mxFrame+1;
+  }
+
+  /* See if it is possible to write these frames into the start of the
+  ** log file, instead of appending to it at pWal->hdr.mxFrame.
+  */
+  if( SQLITE_OK!=(rc = walRestartLog(pWal)) ){
+    return rc;
+  }
+
+  /* If this is the first frame written into the log, write the WAL
+  ** header to the start of the WAL file. See comments at the top of
+  ** this source file for a description of the WAL header format.
+  */
+  iFrame = pWal->hdr.mxFrame;
+  if( iFrame==0 ){
+    u8 aWalHdr[WAL_HDRSIZE];      /* Buffer to assemble wal-header in */
+    u32 aCksum[2];                /* Checksum for wal-header */
+
+    sqlite3Put4byte(&aWalHdr[0], (WAL_MAGIC | SQLITE_BIGENDIAN));
+    sqlite3Put4byte(&aWalHdr[4], WAL_MAX_VERSION);
+    sqlite3Put4byte(&aWalHdr[8], szPage);
+    sqlite3Put4byte(&aWalHdr[12], pWal->nCkpt);
+    if( pWal->nCkpt==0 ) sqlite3_randomness(8, pWal->hdr.aSalt);
+    memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8);
+    walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum);
+    sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
+    sqlite3Put4byte(&aWalHdr[28], aCksum[1]);
+
+    pWal->szPage = szPage;
+    pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
+    pWal->hdr.aFrameCksum[0] = aCksum[0];
+    pWal->hdr.aFrameCksum[1] = aCksum[1];
+    pWal->truncateOnCommit = 1;
+
+    rc = sqlite3OsWrite(pWal->pWalFd, aWalHdr, sizeof(aWalHdr), 0);
+    WALTRACE(("WAL%p: wal-header write %s\n", pWal, rc ? "failed" : "ok"));
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    /* Sync the header (unless SQLITE_IOCAP_SEQUENTIAL is true or unless
+    ** all syncing is turned off by PRAGMA synchronous=OFF).  Otherwise
+    ** an out-of-order write following a WAL restart could result in
+    ** database corruption.  See the ticket:
+    **
+    **     https://sqlite.org/src/info/ff5be73dee
+    */
+    if( pWal->syncHeader ){
+      rc = sqlite3OsSync(pWal->pWalFd, CKPT_SYNC_FLAGS(sync_flags));
+      if( rc ) return rc;
+    }
+  }
+  if( (int)pWal->szPage!=szPage ){
+    return SQLITE_CORRUPT_BKPT;  /* TH3 test case: cov1/corrupt155.test */
+  }
+
+  /* Setup information needed to write frames into the WAL */
+  w.pWal = pWal;
+  w.pFd = pWal->pWalFd;
+  w.iSyncPoint = 0;
+  w.syncFlags = sync_flags;
+  w.szPage = szPage;
+  iOffset = walFrameOffset(iFrame+1, szPage);
+  szFrame = szPage + WAL_FRAME_HDRSIZE;
+
+  /* Write all frames into the log file exactly once */
+  for(p=pList; p; p=p->pDirty){
+    int nDbSize;   /* 0 normally.  Positive == commit flag */
+
+    /* Check if this page has already been written into the wal file by
+    ** the current transaction. If so, overwrite the existing frame and
+    ** set Wal.writeLock to WAL_WRITELOCK_RECKSUM - indicating that
+    ** checksums must be recomputed when the transaction is committed.  */
+    if( iFirst && (p->pDirty || isCommit==0) ){
+      u32 iWrite = 0;
+      VVA_ONLY(rc =) walFindFrame(pWal, p->pgno, &iWrite);
+      assert( rc==SQLITE_OK || iWrite==0 );
+      if( iWrite>=iFirst ){
+        i64 iOff = walFrameOffset(iWrite, szPage) + WAL_FRAME_HDRSIZE;
+        void *pData;
+        if( pWal->iReCksum==0 || iWrite<pWal->iReCksum ){
+          pWal->iReCksum = iWrite;
+        }
+        pData = p->pData;
+        rc = sqlite3OsWrite(pWal->pWalFd, pData, szPage, iOff);
+        if( rc ) return rc;
+        p->flags &= ~PGHDR_WAL_APPEND;
+        continue;
+      }
+    }
+
+    iFrame++;
+    assert( iOffset==walFrameOffset(iFrame, szPage) );
+    nDbSize = (isCommit && p->pDirty==0) ? nTruncate : 0;
+    rc = walWriteOneFrame(&w, p, nDbSize, iOffset);
+    if( rc ) return rc;
+    pLast = p;
+    iOffset += szFrame;
+    p->flags |= PGHDR_WAL_APPEND;
+  }
+
+  /* Recalculate checksums within the wal file if required. */
+  if( isCommit && pWal->iReCksum ){
+    rc = walRewriteChecksums(pWal, iFrame);
+    if( rc ) return rc;
+  }
+
+  /* If this is the end of a transaction, then we might need to pad
+  ** the transaction and/or sync the WAL file.
+  **
+  ** Padding and syncing only occur if this set of frames complete a
+  ** transaction and if PRAGMA synchronous=FULL.  If synchronous==NORMAL
+  ** or synchronous==OFF, then no padding or syncing are needed.
+  **
+  ** If SQLITE_IOCAP_POWERSAFE_OVERWRITE is defined, then padding is not
+  ** needed and only the sync is done.  If padding is needed, then the
+  ** final frame is repeated (with its commit mark) until the next sector
+  ** boundary is crossed.  Only the part of the WAL prior to the last
+  ** sector boundary is synced; the part of the last frame that extends
+  ** past the sector boundary is written after the sync.
+  */
+  if( isCommit && WAL_SYNC_FLAGS(sync_flags)!=0 ){
+    int bSync = 1;
+    if( pWal->padToSectorBoundary ){
+      int sectorSize = sqlite3SectorSize(pWal->pWalFd);
+      w.iSyncPoint = ((iOffset+sectorSize-1)/sectorSize)*sectorSize;
+      bSync = (w.iSyncPoint==iOffset);
+      testcase( bSync );
+      while( iOffset<w.iSyncPoint ){
+        rc = walWriteOneFrame(&w, pLast, nTruncate, iOffset);
+        if( rc ) return rc;
+        iOffset += szFrame;
+        nExtra++;
+        assert( pLast!=0 );
+      }
+    }
+    if( bSync ){
+      assert( rc==SQLITE_OK );
+      rc = sqlite3OsSync(w.pFd, WAL_SYNC_FLAGS(sync_flags));
+    }
+  }
+
+  /* If this frame set completes the first transaction in the WAL and
+  ** if PRAGMA journal_size_limit is set, then truncate the WAL to the
+  ** journal size limit, if possible.
+  */
+  if( isCommit && pWal->truncateOnCommit && pWal->mxWalSize>=0 ){
+    i64 sz = pWal->mxWalSize;
+    if( walFrameOffset(iFrame+nExtra+1, szPage)>pWal->mxWalSize ){
+      sz = walFrameOffset(iFrame+nExtra+1, szPage);
+    }
+    walLimitSize(pWal, sz);
+    pWal->truncateOnCommit = 0;
+  }
+
+  /* Append data to the wal-index. It is not necessary to lock the
+  ** wal-index to do this as the SQLITE_SHM_WRITE lock held on the wal-index
+  ** guarantees that there are no other writers, and no data that may
+  ** be in use by existing readers is being overwritten.
+  */
+  iFrame = pWal->hdr.mxFrame;
+  for(p=pList; p && rc==SQLITE_OK; p=p->pDirty){
+    if( (p->flags & PGHDR_WAL_APPEND)==0 ) continue;
+    iFrame++;
+    rc = walIndexAppend(pWal, iFrame, p->pgno);
+  }
+  assert( pLast!=0 || nExtra==0 );
+  while( rc==SQLITE_OK && nExtra>0 ){
+    iFrame++;
+    nExtra--;
+    rc = walIndexAppend(pWal, iFrame, pLast->pgno);
+  }
+
+  if( rc==SQLITE_OK ){
+    /* Update the private copy of the header. */
+    pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
+    testcase( szPage<=32768 );
+    testcase( szPage>=65536 );
+    pWal->hdr.mxFrame = iFrame;
+    if( isCommit ){
+      pWal->hdr.iChange++;
+      pWal->hdr.nPage = nTruncate;
+    }
+    /* If this is a commit, update the wal-index header too. */
+    if( isCommit ){
+      walIndexWriteHdr(pWal);
+      pWal->iCallback = iFrame;
+    }
+  }
+
+  WALTRACE(("WAL%p: frame write %s\n", pWal, rc ? "failed" : "ok"));
+  return rc;
+}
+
+/*
+** Write a set of frames to the log. The caller must hold the write-lock
+** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
+**
+** The difference between this function and walFrames() is that this
+** function wraps walFrames() in an SEH_TRY{...} block.
+*/
+SQLITE_PRIVATE int sqlite3WalFrames(
+  Wal *pWal,                      /* Wal handle to write to */
+  int szPage,                     /* Database page-size in bytes */
+  PgHdr *pList,                   /* List of dirty pages to write */
+  Pgno nTruncate,                 /* Database size after this commit */
+  int isCommit,                   /* True if this is a commit */
+  int sync_flags                  /* Flags to pass to OsSync() (or 0) */
+){
+  int rc;
+  SEH_TRY {
+    rc = walFrames(pWal, szPage, pList, nTruncate, isCommit, sync_flags);
+  }
+  SEH_EXCEPT( rc = walHandleException(pWal); )
+  return rc;
+}
+
+/*
+** This routine is called to implement sqlite3_wal_checkpoint() and
+** related interfaces.
+**
+** Obtain a CHECKPOINT lock and then backfill as much information as
+** we can from WAL into the database.
+**
+** If parameter xBusy is not NULL, it is a pointer to a busy-handler
+** callback. In this case this function runs a blocking checkpoint.
+*/
+SQLITE_PRIVATE int sqlite3WalCheckpoint(
+  Wal *pWal,                      /* Wal connection */
+  sqlite3 *db,                    /* Check this handle's interrupt flag */
+  int eMode,                      /* PASSIVE, FULL, RESTART, or TRUNCATE */
+  int (*xBusy)(void*),            /* Function to call when busy */
+  void *pBusyArg,                 /* Context argument for xBusyHandler */
+  int sync_flags,                 /* Flags to sync db file with (or 0) */
+  int nBuf,                       /* Size of temporary buffer */
+  u8 *zBuf,                       /* Temporary buffer to use */
+  int *pnLog,                     /* OUT: Number of frames in WAL */
+  int *pnCkpt                     /* OUT: Number of backfilled frames in WAL */
+){
+  int rc;                         /* Return code */
+  int isChanged = 0;              /* True if a new wal-index header is loaded */
+  int eMode2 = eMode;             /* Mode to pass to walCheckpoint() */
+  int (*xBusy2)(void*) = xBusy;   /* Busy handler for eMode2 */
+
+  assert( pWal->ckptLock==0 );
+  assert( pWal->writeLock==0 );
+
+  /* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
+  ** in the SQLITE_CHECKPOINT_PASSIVE mode. */
+  assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );
+
+  if( pWal->readOnly ) return SQLITE_READONLY;
+  WALTRACE(("WAL%p: checkpoint begins\n", pWal));
+
+  /* Enable blocking locks, if possible. */
+  sqlite3WalDb(pWal, db);
+  if( xBusy2 ) (void)walEnableBlocking(pWal);
+
+  /* IMPLEMENTATION-OF: R-62028-47212 All calls obtain an exclusive
+  ** "checkpoint" lock on the database file.
+  ** EVIDENCE-OF: R-10421-19736 If any other process is running a
+  ** checkpoint operation at the same time, the lock cannot be obtained and
+  ** SQLITE_BUSY is returned.
+  ** EVIDENCE-OF: R-53820-33897 Even if there is a busy-handler configured,
+  ** it will not be invoked in this case.
+  */
+  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
+  testcase( rc==SQLITE_BUSY );
+  testcase( rc!=SQLITE_OK && xBusy2!=0 );
+  if( rc==SQLITE_OK ){
+    pWal->ckptLock = 1;
+
+    /* IMPLEMENTATION-OF: R-59782-36818 The SQLITE_CHECKPOINT_FULL, RESTART and
+    ** TRUNCATE modes also obtain the exclusive "writer" lock on the database
+    ** file.
+    **
+    ** EVIDENCE-OF: R-60642-04082 If the writer lock cannot be obtained
+    ** immediately, and a busy-handler is configured, it is invoked and the
+    ** writer lock retried until either the busy-handler returns 0 or the
+    ** lock is successfully obtained.
+    */
+    if( eMode!=SQLITE_CHECKPOINT_PASSIVE ){
+      rc = walBusyLock(pWal, xBusy2, pBusyArg, WAL_WRITE_LOCK, 1);
+      if( rc==SQLITE_OK ){
+        pWal->writeLock = 1;
+      }else if( rc==SQLITE_BUSY ){
+        eMode2 = SQLITE_CHECKPOINT_PASSIVE;
+        xBusy2 = 0;
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+
+  /* Read the wal-index header. */
+  SEH_TRY {
+    if( rc==SQLITE_OK ){
+      /* For a passive checkpoint, do not re-enable blocking locks after
+      ** reading the wal-index header. A passive checkpoint should not block
+      ** or invoke the busy handler. The only lock such a checkpoint may
+      ** attempt to obtain is a lock on a read-slot, and it should give up
+      ** immediately and do a partial checkpoint if it cannot obtain it. */
+      walDisableBlocking(pWal);
+      rc = walIndexReadHdr(pWal, &isChanged);
+      if( eMode2!=SQLITE_CHECKPOINT_PASSIVE ) (void)walEnableBlocking(pWal);
+      if( isChanged && pWal->pDbFd->pMethods->iVersion>=3 ){
+        sqlite3OsUnfetch(pWal->pDbFd, 0, 0);
+      }
+    }
+
+    /* Copy data from the log to the database file. */
+    if( rc==SQLITE_OK ){
+      if( pWal->hdr.mxFrame && walPagesize(pWal)!=nBuf ){
+        rc = SQLITE_CORRUPT_BKPT;
+      }else{
+        rc = walCheckpoint(pWal, db, eMode2, xBusy2, pBusyArg, sync_flags,zBuf);
+      }
+
+      /* If no error occurred, set the output variables. */
+      if( rc==SQLITE_OK || rc==SQLITE_BUSY ){
+        if( pnLog ) *pnLog = (int)pWal->hdr.mxFrame;
+        SEH_INJECT_FAULT;
+        if( pnCkpt ) *pnCkpt = (int)(walCkptInfo(pWal)->nBackfill);
+      }
+    }
+  }
+  SEH_EXCEPT( rc = walHandleException(pWal); )
+
+  if( isChanged ){
+    /* If a new wal-index header was loaded before the checkpoint was
+    ** performed, then the pager-cache associated with pWal is now
+    ** out of date. So zero the cached wal-index header to ensure that
+    ** next time the pager opens a snapshot on this database it knows that
+    ** the cache needs to be reset.
+    */
+    memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
+  }
+
+  walDisableBlocking(pWal);
+  sqlite3WalDb(pWal, 0);
+
+  /* Release the locks. */
+  sqlite3WalEndWriteTransaction(pWal);
+  if( pWal->ckptLock ){
+    walUnlockExclusive(pWal, WAL_CKPT_LOCK, 1);
+    pWal->ckptLock = 0;
+  }
+  WALTRACE(("WAL%p: checkpoint %s\n", pWal, rc ? "failed" : "ok"));
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  if( rc==SQLITE_BUSY_TIMEOUT ) rc = SQLITE_BUSY;
+#endif
+  return (rc==SQLITE_OK && eMode!=eMode2 ? SQLITE_BUSY : rc);
+}
+
+/* Return the value to pass to a sqlite3_wal_hook callback, the
+** number of frames in the WAL at the point of the last commit since
+** sqlite3WalCallback() was called.  If no commits have occurred since
+** the last call, then return 0.
+*/
+SQLITE_PRIVATE int sqlite3WalCallback(Wal *pWal){
+  u32 ret = 0;
+  if( pWal ){
+    ret = pWal->iCallback;
+    pWal->iCallback = 0;
+  }
+  return (int)ret;
+}
+
+/*
+** This function is called to change the WAL subsystem into or out
+** of locking_mode=EXCLUSIVE.
+**
+** If op is zero, then attempt to change from locking_mode=EXCLUSIVE
+** into locking_mode=NORMAL.  This means that we must acquire a lock
+** on the pWal->readLock byte.  If the WAL is already in locking_mode=NORMAL
+** or if the acquisition of the lock fails, then return 0.  If the
+** transition out of exclusive-mode is successful, return 1.  This
+** operation must occur while the pager is still holding the exclusive
+** lock on the main database file.
+**
+** If op is one, then change from locking_mode=NORMAL into
+** locking_mode=EXCLUSIVE.  This means that the pWal->readLock must
+** be released.  Return 1 if the transition is made and 0 if the
+** WAL is already in exclusive-locking mode - meaning that this
+** routine is a no-op.  The pager must already hold the exclusive lock
+** on the main database file before invoking this operation.
+**
+** If op is negative, then do a dry-run of the op==1 case but do
+** not actually change anything. The pager uses this to see if it
+** should acquire the database exclusive lock prior to invoking
+** the op==1 case.
+*/
+SQLITE_PRIVATE int sqlite3WalExclusiveMode(Wal *pWal, int op){
+  int rc;
+  assert( pWal->writeLock==0 );
+  assert( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE || op==-1 );
+
+  /* pWal->readLock is usually set, but might be -1 if there was a
+  ** prior error while attempting to acquire are read-lock. This cannot
+  ** happen if the connection is actually in exclusive mode (as no xShmLock
+  ** locks are taken in this case). Nor should the pager attempt to
+  ** upgrade to exclusive-mode following such an error.
+  */
+#ifndef SQLITE_USE_SEH
+  assert( pWal->readLock>=0 || pWal->lockError );
+#endif
+  assert( pWal->readLock>=0 || (op<=0 && pWal->exclusiveMode==0) );
+
+  if( op==0 ){
+    if( pWal->exclusiveMode!=WAL_NORMAL_MODE ){
+      pWal->exclusiveMode = WAL_NORMAL_MODE;
+      if( walLockShared(pWal, WAL_READ_LOCK(pWal->readLock))!=SQLITE_OK ){
+        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
+      }
+      rc = pWal->exclusiveMode==WAL_NORMAL_MODE;
+    }else{
+      /* Already in locking_mode=NORMAL */
+      rc = 0;
+    }
+  }else if( op>0 ){
+    assert( pWal->exclusiveMode==WAL_NORMAL_MODE );
+    assert( pWal->readLock>=0 );
+    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
+    pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
+    rc = 1;
+  }else{
+    rc = pWal->exclusiveMode==WAL_NORMAL_MODE;
+  }
+  return rc;
+}
+
+/*
+** Return true if the argument is non-NULL and the WAL module is using
+** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
+** WAL module is using shared-memory, return false.
+*/
+SQLITE_PRIVATE int sqlite3WalHeapMemory(Wal *pWal){
+  return (pWal && pWal->exclusiveMode==WAL_HEAPMEMORY_MODE );
+}
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+/* Create a snapshot object.  The content of a snapshot is opaque to
+** every other subsystem, so the WAL module can put whatever it needs
+** in the object.
+*/
+SQLITE_PRIVATE int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot){
+  int rc = SQLITE_OK;
+  WalIndexHdr *pRet;
+  static const u32 aZero[4] = { 0, 0, 0, 0 };
+
+  assert( pWal->readLock>=0 && pWal->writeLock==0 );
+
+  if( memcmp(&pWal->hdr.aFrameCksum[0],aZero,16)==0 ){
+    *ppSnapshot = 0;
+    return SQLITE_ERROR;
+  }
+  pRet = (WalIndexHdr*)sqlite3_malloc(sizeof(WalIndexHdr));
+  if( pRet==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+  }else{
+    memcpy(pRet, &pWal->hdr, sizeof(WalIndexHdr));
+    *ppSnapshot = (sqlite3_snapshot*)pRet;
+  }
+
+  return rc;
+}
+
+/* Try to open on pSnapshot when the next read-transaction starts
+*/
+SQLITE_PRIVATE void sqlite3WalSnapshotOpen(
+  Wal *pWal,
+  sqlite3_snapshot *pSnapshot
+){
+  if( pSnapshot && ((WalIndexHdr*)pSnapshot)->iVersion==0 ){
+    /* iVersion==0 means that this is a call to sqlite3_snapshot_get().  In
+    ** this case set the bGetSnapshot flag so that if the call to
+    ** sqlite3_snapshot_get() is about to read transaction on this wal
+    ** file, it does not take read-lock 0 if the wal file has been completely
+    ** checkpointed. Taking read-lock 0 would work, but then it would be
+    ** possible for a subsequent writer to destroy the snapshot even while
+    ** this connection is holding its read-transaction open. This is contrary
+    ** to user expectations, so we avoid it by not taking read-lock 0. */
+    pWal->bGetSnapshot = 1;
+  }else{
+    pWal->pSnapshot = (WalIndexHdr*)pSnapshot;
+    pWal->bGetSnapshot = 0;
+  }
+}
+
+/*
+** Return a +ve value if snapshot p1 is newer than p2. A -ve value if
+** p1 is older than p2 and zero if p1 and p2 are the same snapshot.
+*/
+SQLITE_API int sqlite3_snapshot_cmp(sqlite3_snapshot *p1, sqlite3_snapshot *p2){
+  WalIndexHdr *pHdr1 = (WalIndexHdr*)p1;
+  WalIndexHdr *pHdr2 = (WalIndexHdr*)p2;
+
+  /* aSalt[0] is a copy of the value stored in the wal file header. It
+  ** is incremented each time the wal file is restarted.  */
+  if( pHdr1->aSalt[0]<pHdr2->aSalt[0] ) return -1;
+  if( pHdr1->aSalt[0]>pHdr2->aSalt[0] ) return +1;
+  if( pHdr1->mxFrame<pHdr2->mxFrame ) return -1;
+  if( pHdr1->mxFrame>pHdr2->mxFrame ) return +1;
+  return 0;
+}
+
+/*
+** The caller currently has a read transaction open on the database.
+** This function takes a SHARED lock on the CHECKPOINTER slot and then
+** checks if the snapshot passed as the second argument is still
+** available. If so, SQLITE_OK is returned.
+**
+** If the snapshot is not available, SQLITE_ERROR is returned. Or, if
+** the CHECKPOINTER lock cannot be obtained, SQLITE_BUSY. If any error
+** occurs (any value other than SQLITE_OK is returned), the CHECKPOINTER
+** lock is released before returning.
+*/
+SQLITE_PRIVATE int sqlite3WalSnapshotCheck(Wal *pWal, sqlite3_snapshot *pSnapshot){
+  int rc;
+  SEH_TRY {
+    rc = walLockShared(pWal, WAL_CKPT_LOCK);
+    if( rc==SQLITE_OK ){
+      WalIndexHdr *pNew = (WalIndexHdr*)pSnapshot;
+      if( memcmp(pNew->aSalt, pWal->hdr.aSalt, sizeof(pWal->hdr.aSalt))
+       || pNew->mxFrame<walCkptInfo(pWal)->nBackfillAttempted
+      ){
+        rc = SQLITE_ERROR_SNAPSHOT;
+        walUnlockShared(pWal, WAL_CKPT_LOCK);
+      }
+    }
+  }
+  SEH_EXCEPT( rc = walHandleException(pWal); )
+  return rc;
+}
+
+/*
+** Release a lock obtained by an earlier successful call to
+** sqlite3WalSnapshotCheck().
+*/
+SQLITE_PRIVATE void sqlite3WalSnapshotUnlock(Wal *pWal){
+  assert( pWal );
+  walUnlockShared(pWal, WAL_CKPT_LOCK);
+}
+
+
+#endif /* SQLITE_ENABLE_SNAPSHOT */
+
+#ifdef SQLITE_ENABLE_ZIPVFS
+/*
+** If the argument is not NULL, it points to a Wal object that holds a
+** read-lock. This function returns the database page-size if it is known,
+** or zero if it is not (or if pWal is NULL).
+*/
+SQLITE_PRIVATE int sqlite3WalFramesize(Wal *pWal){
+  assert( pWal==0 || pWal->readLock>=0 );
+  return (pWal ? pWal->szPage : 0);
+}
+#endif
+
+/* Return the sqlite3_file object for the WAL file
+*/
+SQLITE_PRIVATE sqlite3_file *sqlite3WalFile(Wal *pWal){
+  return pWal->pWalFd;
+}
+
+#endif /* #ifndef SQLITE_OMIT_WAL */
+
+/************** End of wal.c *************************************************/
+/************** Begin file btmutex.c *****************************************/
+/*
+** 2007 August 27
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code used to implement mutexes on Btree objects.
+** This code really belongs in btree.c.  But btree.c is getting too
+** big and we want to break it down some.  This packaged seemed like
+** a good breakout.
+*/
+/************** Include btreeInt.h in the middle of btmutex.c ****************/
+/************** Begin file btreeInt.h ****************************************/
+/*
+** 2004 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements an external (disk-based) database using BTrees.
+** For a detailed discussion of BTrees, refer to
+**
+**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
+**     "Sorting And Searching", pages 473-480. Addison-Wesley
+**     Publishing Company, Reading, Massachusetts.
+**
+** The basic idea is that each page of the file contains N database
+** entries and N+1 pointers to subpages.
+**
+**   ----------------------------------------------------------------
+**   |  Ptr(0) | Key(0) | Ptr(1) | Key(1) | ... | Key(N-1) | Ptr(N) |
+**   ----------------------------------------------------------------
+**
+** All of the keys on the page that Ptr(0) points to have values less
+** than Key(0).  All of the keys on page Ptr(1) and its subpages have
+** values greater than Key(0) and less than Key(1).  All of the keys
+** on Ptr(N) and its subpages have values greater than Key(N-1).  And
+** so forth.
+**
+** Finding a particular key requires reading O(log(M)) pages from the
+** disk where M is the number of entries in the tree.
+**
+** In this implementation, a single file can hold one or more separate
+** BTrees.  Each BTree is identified by the index of its root page.  The
+** key and data for any entry are combined to form the "payload".  A
+** fixed amount of payload can be carried directly on the database
+** page.  If the payload is larger than the preset amount then surplus
+** bytes are stored on overflow pages.  The payload for an entry
+** and the preceding pointer are combined to form a "Cell".  Each
+** page has a small header which contains the Ptr(N) pointer and other
+** information such as the size of key and data.
+**
+** FORMAT DETAILS
+**
+** The file is divided into pages.  The first page is called page 1,
+** the second is page 2, and so forth.  A page number of zero indicates
+** "no such page".  The page size can be any power of 2 between 512 and 65536.
+** Each page can be either a btree page, a freelist page, an overflow
+** page, or a pointer-map page.
+**
+** The first page is always a btree page.  The first 100 bytes of the first
+** page contain a special header (the "file header") that describes the file.
+** The format of the file header is as follows:
+**
+**   OFFSET   SIZE    DESCRIPTION
+**      0      16     Header string: "SQLite format 3\000"
+**     16       2     Page size in bytes.  (1 means 65536)
+**     18       1     File format write version
+**     19       1     File format read version
+**     20       1     Bytes of unused space at the end of each page
+**     21       1     Max embedded payload fraction (must be 64)
+**     22       1     Min embedded payload fraction (must be 32)
+**     23       1     Min leaf payload fraction (must be 32)
+**     24       4     File change counter
+**     28       4     The size of the database in pages
+**     32       4     First freelist page
+**     36       4     Number of freelist pages in the file
+**     40      60     15 4-byte meta values passed to higher layers
+**
+**     40       4     Schema cookie
+**     44       4     File format of schema layer
+**     48       4     Size of page cache
+**     52       4     Largest root-page (auto/incr_vacuum)
+**     56       4     1=UTF-8 2=UTF16le 3=UTF16be
+**     60       4     User version
+**     64       4     Incremental vacuum mode
+**     68       4     Application-ID
+**     72      20     unused
+**     92       4     The version-valid-for number
+**     96       4     SQLITE_VERSION_NUMBER
+**
+** All of the integer values are big-endian (most significant byte first).
+**
+** The file change counter is incremented when the database is changed
+** This counter allows other processes to know when the file has changed
+** and thus when they need to flush their cache.
+**
+** The max embedded payload fraction is the amount of the total usable
+** space in a page that can be consumed by a single cell for standard
+** B-tree (non-LEAFDATA) tables.  A value of 255 means 100%.  The default
+** is to limit the maximum cell size so that at least 4 cells will fit
+** on one page.  Thus the default max embedded payload fraction is 64.
+**
+** If the payload for a cell is larger than the max payload, then extra
+** payload is spilled to overflow pages.  Once an overflow page is allocated,
+** as many bytes as possible are moved into the overflow pages without letting
+** the cell size drop below the min embedded payload fraction.
+**
+** The min leaf payload fraction is like the min embedded payload fraction
+** except that it applies to leaf nodes in a LEAFDATA tree.  The maximum
+** payload fraction for a LEAFDATA tree is always 100% (or 255) and it
+** not specified in the header.
+**
+** Each btree pages is divided into three sections:  The header, the
+** cell pointer array, and the cell content area.  Page 1 also has a 100-byte
+** file header that occurs before the page header.
+**
+**      |----------------|
+**      | file header    |   100 bytes.  Page 1 only.
+**      |----------------|
+**      | page header    |   8 bytes for leaves.  12 bytes for interior nodes
+**      |----------------|
+**      | cell pointer   |   |  2 bytes per cell.  Sorted order.
+**      | array          |   |  Grows downward
+**      |                |   v
+**      |----------------|
+**      | unallocated    |
+**      | space          |
+**      |----------------|   ^  Grows upwards
+**      | cell content   |   |  Arbitrary order interspersed with freeblocks.
+**      | area           |   |  and free space fragments.
+**      |----------------|
+**
+** The page headers looks like this:
+**
+**   OFFSET   SIZE     DESCRIPTION
+**      0       1      Flags. 1: intkey, 2: zerodata, 4: leafdata, 8: leaf
+**      1       2      byte offset to the first freeblock
+**      3       2      number of cells on this page
+**      5       2      first byte of the cell content area
+**      7       1      number of fragmented free bytes
+**      8       4      Right child (the Ptr(N) value).  Omitted on leaves.
+**
+** The flags define the format of this btree page.  The leaf flag means that
+** this page has no children.  The zerodata flag means that this page carries
+** only keys and no data.  The intkey flag means that the key is an integer
+** which is stored in the key size entry of the cell header rather than in
+** the payload area.
+**
+** The cell pointer array begins on the first byte after the page header.
+** The cell pointer array contains zero or more 2-byte numbers which are
+** offsets from the beginning of the page to the cell content in the cell
+** content area.  The cell pointers occur in sorted order.  The system strives
+** to keep free space after the last cell pointer so that new cells can
+** be easily added without having to defragment the page.
+**
+** Cell content is stored at the very end of the page and grows toward the
+** beginning of the page.
+**
+** Unused space within the cell content area is collected into a linked list of
+** freeblocks.  Each freeblock is at least 4 bytes in size.  The byte offset
+** to the first freeblock is given in the header.  Freeblocks occur in
+** increasing order.  Because a freeblock must be at least 4 bytes in size,
+** any group of 3 or fewer unused bytes in the cell content area cannot
+** exist on the freeblock chain.  A group of 3 or fewer free bytes is called
+** a fragment.  The total number of bytes in all fragments is recorded.
+** in the page header at offset 7.
+**
+**    SIZE    DESCRIPTION
+**      2     Byte offset of the next freeblock
+**      2     Bytes in this freeblock
+**
+** Cells are of variable length.  Cells are stored in the cell content area at
+** the end of the page.  Pointers to the cells are in the cell pointer array
+** that immediately follows the page header.  Cells is not necessarily
+** contiguous or in order, but cell pointers are contiguous and in order.
+**
+** Cell content makes use of variable length integers.  A variable
+** length integer is 1 to 9 bytes where the lower 7 bits of each
+** byte are used.  The integer consists of all bytes that have bit 8 set and
+** the first byte with bit 8 clear.  The most significant byte of the integer
+** appears first.  A variable-length integer may not be more than 9 bytes long.
+** As a special case, all 8 bits of the 9th byte are used as data.  This
+** allows a 64-bit integer to be encoded in 9 bytes.
+**
+**    0x00                      becomes  0x00000000
+**    0x7f                      becomes  0x0000007f
+**    0x81 0x00                 becomes  0x00000080
+**    0x82 0x00                 becomes  0x00000100
+**    0x80 0x7f                 becomes  0x0000007f
+**    0x81 0x91 0xd1 0xac 0x78  becomes  0x12345678
+**    0x81 0x81 0x81 0x81 0x01  becomes  0x10204081
+**
+** Variable length integers are used for rowids and to hold the number of
+** bytes of key and data in a btree cell.
+**
+** The content of a cell looks like this:
+**
+**    SIZE    DESCRIPTION
+**      4     Page number of the left child. Omitted if leaf flag is set.
+**     var    Number of bytes of data. Omitted if the zerodata flag is set.
+**     var    Number of bytes of key. Or the key itself if intkey flag is set.
+**      *     Payload
+**      4     First page of the overflow chain.  Omitted if no overflow
+**
+** Overflow pages form a linked list.  Each page except the last is completely
+** filled with data (pagesize - 4 bytes).  The last page can have as little
+** as 1 byte of data.
+**
+**    SIZE    DESCRIPTION
+**      4     Page number of next overflow page
+**      *     Data
+**
+** Freelist pages come in two subtypes: trunk pages and leaf pages.  The
+** file header points to the first in a linked list of trunk page.  Each trunk
+** page points to multiple leaf pages.  The content of a leaf page is
+** unspecified.  A trunk page looks like this:
+**
+**    SIZE    DESCRIPTION
+**      4     Page number of next trunk page
+**      4     Number of leaf pointers on this page
+**      *     zero or more pages numbers of leaves
+*/
+/* #include "sqliteInt.h" */
+
+
+/* The following value is the maximum cell size assuming a maximum page
+** size give above.
+*/
+#define MX_CELL_SIZE(pBt)  ((int)(pBt->pageSize-8))
+
+/* The maximum number of cells on a single page of the database.  This
+** assumes a minimum cell size of 6 bytes  (4 bytes for the cell itself
+** plus 2 bytes for the index to the cell in the page header).  Such
+** small cells will be rare, but they are possible.
+*/
+#define MX_CELL(pBt) ((pBt->pageSize-8)/6)
+
+/* Forward declarations */
+typedef struct MemPage MemPage;
+typedef struct BtLock BtLock;
+typedef struct CellInfo CellInfo;
+
+/*
+** This is a magic string that appears at the beginning of every
+** SQLite database in order to identify the file as a real database.
+**
+** You can change this value at compile-time by specifying a
+** -DSQLITE_FILE_HEADER="..." on the compiler command-line.  The
+** header must be exactly 16 bytes including the zero-terminator so
+** the string itself should be 15 characters long.  If you change
+** the header, then your custom library will not be able to read
+** databases generated by the standard tools and the standard tools
+** will not be able to read databases created by your custom library.
+*/
+#ifndef SQLITE_FILE_HEADER /* 123456789 123456 */
+#  define SQLITE_FILE_HEADER "SQLite format 3"
+#endif
+
+/*
+** Page type flags.  An ORed combination of these flags appear as the
+** first byte of on-disk image of every BTree page.
+*/
+#define PTF_INTKEY    0x01
+#define PTF_ZERODATA  0x02
+#define PTF_LEAFDATA  0x04
+#define PTF_LEAF      0x08
+
+/*
+** An instance of this object stores information about each a single database
+** page that has been loaded into memory.  The information in this object
+** is derived from the raw on-disk page content.
+**
+** As each database page is loaded into memory, the pager allocates an
+** instance of this object and zeros the first 8 bytes.  (This is the
+** "extra" information associated with each page of the pager.)
+**
+** Access to all fields of this structure is controlled by the mutex
+** stored in MemPage.pBt->mutex.
+*/
+struct MemPage {
+  u8 isInit;           /* True if previously initialized. MUST BE FIRST! */
+  u8 intKey;           /* True if table b-trees.  False for index b-trees */
+  u8 intKeyLeaf;       /* True if the leaf of an intKey table */
+  Pgno pgno;           /* Page number for this page */
+  /* Only the first 8 bytes (above) are zeroed by pager.c when a new page
+  ** is allocated. All fields that follow must be initialized before use */
+  u8 leaf;             /* True if a leaf page */
+  u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
+  u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */
+  u8 max1bytePayload;  /* min(maxLocal,127) */
+  u8 nOverflow;        /* Number of overflow cell bodies in aCell[] */
+  u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
+  u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
+  u16 cellOffset;      /* Index in aData of first cell pointer */
+  int nFree;           /* Number of free bytes on the page. -1 for unknown */
+  u16 nCell;           /* Number of cells on this page, local and ovfl */
+  u16 maskPage;        /* Mask for page offset */
+  u16 aiOvfl[4];       /* Insert the i-th overflow cell before the aiOvfl-th
+                       ** non-overflow cell */
+  u8 *apOvfl[4];       /* Pointers to the body of overflow cells */
+  BtShared *pBt;       /* Pointer to BtShared that this page is part of */
+  u8 *aData;           /* Pointer to disk image of the page data */
+  u8 *aDataEnd;        /* One byte past the end of the entire page - not just
+                       ** the usable space, the entire page.  Used to prevent
+                       ** corruption-induced buffer overflow. */
+  u8 *aCellIdx;        /* The cell index area */
+  u8 *aDataOfst;       /* Same as aData for leaves.  aData+4 for interior */
+  DbPage *pDbPage;     /* Pager page handle */
+  u16 (*xCellSize)(MemPage*,u8*);             /* cellSizePtr method */
+  void (*xParseCell)(MemPage*,u8*,CellInfo*); /* btreeParseCell method */
+};
+
+/*
+** A linked list of the following structures is stored at BtShared.pLock.
+** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor
+** is opened on the table with root page BtShared.iTable. Locks are removed
+** from this list when a transaction is committed or rolled back, or when
+** a btree handle is closed.
+*/
+struct BtLock {
+  Btree *pBtree;        /* Btree handle holding this lock */
+  Pgno iTable;          /* Root page of table */
+  u8 eLock;             /* READ_LOCK or WRITE_LOCK */
+  BtLock *pNext;        /* Next in BtShared.pLock list */
+};
+
+/* Candidate values for BtLock.eLock */
+#define READ_LOCK     1
+#define WRITE_LOCK    2
+
+/* A Btree handle
+**
+** A database connection contains a pointer to an instance of
+** this object for every database file that it has open.  This structure
+** is opaque to the database connection.  The database connection cannot
+** see the internals of this structure and only deals with pointers to
+** this structure.
+**
+** For some database files, the same underlying database cache might be
+** shared between multiple connections.  In that case, each connection
+** has it own instance of this object.  But each instance of this object
+** points to the same BtShared object.  The database cache and the
+** schema associated with the database file are all contained within
+** the BtShared object.
+**
+** All fields in this structure are accessed under sqlite3.mutex.
+** The pBt pointer itself may not be changed while there exists cursors
+** in the referenced BtShared that point back to this Btree since those
+** cursors have to go through this Btree to find their BtShared and
+** they often do so without holding sqlite3.mutex.
+*/
+struct Btree {
+  sqlite3 *db;       /* The database connection holding this btree */
+  BtShared *pBt;     /* Sharable content of this btree */
+  u8 inTrans;        /* TRANS_NONE, TRANS_READ or TRANS_WRITE */
+  u8 sharable;       /* True if we can share pBt with another db */
+  u8 locked;         /* True if db currently has pBt locked */
+  u8 hasIncrblobCur; /* True if there are one or more Incrblob cursors */
+  int wantToLock;    /* Number of nested calls to sqlite3BtreeEnter() */
+  int nBackup;       /* Number of backup operations reading this btree */
+  u32 iBDataVersion; /* Combines with pBt->pPager->iDataVersion */
+  Btree *pNext;      /* List of other sharable Btrees from the same db */
+  Btree *pPrev;      /* Back pointer of the same list */
+#ifdef SQLITE_DEBUG
+  u64 nSeek;         /* Calls to sqlite3BtreeMovetoUnpacked() */
+#endif
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  BtLock lock;       /* Object used to lock page 1 */
+#endif
+};
+
+/*
+** Btree.inTrans may take one of the following values.
+**
+** If the shared-data extension is enabled, there may be multiple users
+** of the Btree structure. At most one of these may open a write transaction,
+** but any number may have active read transactions.
+**
+** These values must match SQLITE_TXN_NONE, SQLITE_TXN_READ, and
+** SQLITE_TXN_WRITE
+*/
+#define TRANS_NONE  0
+#define TRANS_READ  1
+#define TRANS_WRITE 2
+
+#if TRANS_NONE!=SQLITE_TXN_NONE
+# error wrong numeric code for no-transaction
+#endif
+#if TRANS_READ!=SQLITE_TXN_READ
+# error wrong numeric code for read-transaction
+#endif
+#if TRANS_WRITE!=SQLITE_TXN_WRITE
+# error wrong numeric code for write-transaction
+#endif
+
+
+/*
+** An instance of this object represents a single database file.
+**
+** A single database file can be in use at the same time by two
+** or more database connections.  When two or more connections are
+** sharing the same database file, each connection has it own
+** private Btree object for the file and each of those Btrees points
+** to this one BtShared object.  BtShared.nRef is the number of
+** connections currently sharing this database file.
+**
+** Fields in this structure are accessed under the BtShared.mutex
+** mutex, except for nRef and pNext which are accessed under the
+** global SQLITE_MUTEX_STATIC_MAIN mutex.  The pPager field
+** may not be modified once it is initially set as long as nRef>0.
+** The pSchema field may be set once under BtShared.mutex and
+** thereafter is unchanged as long as nRef>0.
+**
+** isPending:
+**
+**   If a BtShared client fails to obtain a write-lock on a database
+**   table (because there exists one or more read-locks on the table),
+**   the shared-cache enters 'pending-lock' state and isPending is
+**   set to true.
+**
+**   The shared-cache leaves the 'pending lock' state when either of
+**   the following occur:
+**
+**     1) The current writer (BtShared.pWriter) concludes its transaction, OR
+**     2) The number of locks held by other connections drops to zero.
+**
+**   while in the 'pending-lock' state, no connection may start a new
+**   transaction.
+**
+**   This feature is included to help prevent writer-starvation.
+*/
+struct BtShared {
+  Pager *pPager;        /* The page cache */
+  sqlite3 *db;          /* Database connection currently using this Btree */
+  BtCursor *pCursor;    /* A list of all open cursors */
+  MemPage *pPage1;      /* First page of the database */
+  u8 openFlags;         /* Flags to sqlite3BtreeOpen() */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  u8 autoVacuum;        /* True if auto-vacuum is enabled */
+  u8 incrVacuum;        /* True if incr-vacuum is enabled */
+  u8 bDoTruncate;       /* True to truncate db on commit */
+#endif
+  u8 inTransaction;     /* Transaction state */
+  u8 max1bytePayload;   /* Maximum first byte of cell for a 1-byte payload */
+  u8 nReserveWanted;    /* Desired number of extra bytes per page */
+  u16 btsFlags;         /* Boolean parameters.  See BTS_* macros below */
+  u16 maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
+  u16 minLocal;         /* Minimum local payload in non-LEAFDATA tables */
+  u16 maxLeaf;          /* Maximum local payload in a LEAFDATA table */
+  u16 minLeaf;          /* Minimum local payload in a LEAFDATA table */
+  u32 pageSize;         /* Total number of bytes on a page */
+  u32 usableSize;       /* Number of usable bytes on each page */
+  int nTransaction;     /* Number of open transactions (read + write) */
+  u32 nPage;            /* Number of pages in the database */
+  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
+  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
+  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this object */
+  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  int nRef;             /* Number of references to this structure */
+  BtShared *pNext;      /* Next on a list of sharable BtShared structs */
+  BtLock *pLock;        /* List of locks held on this shared-btree struct */
+  Btree *pWriter;       /* Btree with currently open write transaction */
+#endif
+  u8 *pTmpSpace;        /* Temp space sufficient to hold a single cell */
+  int nPreformatSize;   /* Size of last cell written by TransferRow() */
+};
+
+/*
+** Allowed values for BtShared.btsFlags
+*/
+#define BTS_READ_ONLY        0x0001   /* Underlying file is readonly */
+#define BTS_PAGESIZE_FIXED   0x0002   /* Page size can no longer be changed */
+#define BTS_SECURE_DELETE    0x0004   /* PRAGMA secure_delete is enabled */
+#define BTS_OVERWRITE        0x0008   /* Overwrite deleted content with zeros */
+#define BTS_FAST_SECURE      0x000c   /* Combination of the previous two */
+#define BTS_INITIALLY_EMPTY  0x0010   /* Database was empty at trans start */
+#define BTS_NO_WAL           0x0020   /* Do not open write-ahead-log files */
+#define BTS_EXCLUSIVE        0x0040   /* pWriter has an exclusive lock */
+#define BTS_PENDING          0x0080   /* Waiting for read-locks to clear */
+
+/*
+** An instance of the following structure is used to hold information
+** about a cell.  The parseCellPtr() function fills in this structure
+** based on information extract from the raw disk page.
+*/
+struct CellInfo {
+  i64 nKey;      /* The key for INTKEY tables, or nPayload otherwise */
+  u8 *pPayload;  /* Pointer to the start of payload */
+  u32 nPayload;  /* Bytes of payload */
+  u16 nLocal;    /* Amount of payload held locally, not on overflow */
+  u16 nSize;     /* Size of the cell content on the main b-tree page */
+};
+
+/*
+** Maximum depth of an SQLite B-Tree structure. Any B-Tree deeper than
+** this will be declared corrupt. This value is calculated based on a
+** maximum database size of 2^31 pages a minimum fanout of 2 for a
+** root-node and 3 for all other internal nodes.
+**
+** If a tree that appears to be taller than this is encountered, it is
+** assumed that the database is corrupt.
+*/
+#define BTCURSOR_MAX_DEPTH 20
+
+/*
+** A cursor is a pointer to a particular entry within a particular
+** b-tree within a database file.
+**
+** The entry is identified by its MemPage and the index in
+** MemPage.aCell[] of the entry.
+**
+** A single database file can be shared by two more database connections,
+** but cursors cannot be shared.  Each cursor is associated with a
+** particular database connection identified BtCursor.pBtree.db.
+**
+** Fields in this structure are accessed under the BtShared.mutex
+** found at self->pBt->mutex.
+**
+** skipNext meaning:
+** The meaning of skipNext depends on the value of eState:
+**
+**   eState            Meaning of skipNext
+**   VALID             skipNext is meaningless and is ignored
+**   INVALID           skipNext is meaningless and is ignored
+**   SKIPNEXT          sqlite3BtreeNext() is a no-op if skipNext>0 and
+**                     sqlite3BtreePrevious() is no-op if skipNext<0.
+**   REQUIRESEEK       restoreCursorPosition() restores the cursor to
+**                     eState=SKIPNEXT if skipNext!=0
+**   FAULT             skipNext holds the cursor fault error code.
+*/
+struct BtCursor {
+  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
+  u8 curFlags;              /* zero or more BTCF_* flags defined below */
+  u8 curPagerFlags;         /* Flags to send to sqlite3PagerGet() */
+  u8 hints;                 /* As configured by CursorSetHints() */
+  int skipNext;    /* Prev() is noop if negative. Next() is noop if positive.
+                   ** Error code if eState==CURSOR_FAULT */
+  Btree *pBtree;            /* The Btree to which this cursor belongs */
+  Pgno *aOverflow;          /* Cache of overflow page locations */
+  void *pKey;               /* Saved key that was cursor last known position */
+  /* All fields above are zeroed when the cursor is allocated.  See
+  ** sqlite3BtreeCursorZero().  Fields that follow must be manually
+  ** initialized. */
+#define BTCURSOR_FIRST_UNINIT pBt   /* Name of first uninitialized field */
+  BtShared *pBt;            /* The BtShared this cursor points to */
+  BtCursor *pNext;          /* Forms a linked list of all cursors */
+  CellInfo info;            /* A parse of the cell we are pointing at */
+  i64 nKey;                 /* Size of pKey, or last integer key */
+  Pgno pgnoRoot;            /* The root page of this tree */
+  i8 iPage;                 /* Index of current page in apPage */
+  u8 curIntKey;             /* Value of apPage[0]->intKey */
+  u16 ix;                   /* Current index for apPage[iPage] */
+  u16 aiIdx[BTCURSOR_MAX_DEPTH-1];     /* Current index in apPage[i] */
+  struct KeyInfo *pKeyInfo;            /* Arg passed to comparison function */
+  MemPage *pPage;                        /* Current page */
+  MemPage *apPage[BTCURSOR_MAX_DEPTH-1]; /* Stack of parents of current page */
+};
+
+/*
+** Legal values for BtCursor.curFlags
+*/
+#define BTCF_WriteFlag    0x01   /* True if a write cursor */
+#define BTCF_ValidNKey    0x02   /* True if info.nKey is valid */
+#define BTCF_ValidOvfl    0x04   /* True if aOverflow is valid */
+#define BTCF_AtLast       0x08   /* Cursor is pointing to the last entry */
+#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */
+#define BTCF_Multiple     0x20   /* Maybe another cursor on the same btree */
+#define BTCF_Pinned       0x40   /* Cursor is busy and cannot be moved */
+
+/*
+** Potential values for BtCursor.eState.
+**
+** CURSOR_INVALID:
+**   Cursor does not point to a valid entry. This can happen (for example)
+**   because the table is empty or because BtreeCursorFirst() has not been
+**   called.
+**
+** CURSOR_VALID:
+**   Cursor points to a valid entry. getPayload() etc. may be called.
+**
+** CURSOR_SKIPNEXT:
+**   Cursor is valid except that the Cursor.skipNext field is non-zero
+**   indicating that the next sqlite3BtreeNext() or sqlite3BtreePrevious()
+**   operation should be a no-op.
+**
+** CURSOR_REQUIRESEEK:
+**   The table that this cursor was opened on still exists, but has been
+**   modified since the cursor was last used. The cursor position is saved
+**   in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in
+**   this state, restoreCursorPosition() can be called to attempt to
+**   seek the cursor to the saved position.
+**
+** CURSOR_FAULT:
+**   An unrecoverable error (an I/O error or a malloc failure) has occurred
+**   on a different connection that shares the BtShared cache with this
+**   cursor.  The error has left the cache in an inconsistent state.
+**   Do nothing else with this cursor.  Any attempt to use the cursor
+**   should return the error code stored in BtCursor.skipNext
+*/
+#define CURSOR_VALID             0
+#define CURSOR_INVALID           1
+#define CURSOR_SKIPNEXT          2
+#define CURSOR_REQUIRESEEK       3
+#define CURSOR_FAULT             4
+
+/*
+** The database page the PENDING_BYTE occupies. This page is never used.
+*/
+#define PENDING_BYTE_PAGE(pBt)  ((Pgno)((PENDING_BYTE/((pBt)->pageSize))+1))
+
+/*
+** These macros define the location of the pointer-map entry for a
+** database page. The first argument to each is the number of usable
+** bytes on each page of the database (often 1024). The second is the
+** page number to look up in the pointer map.
+**
+** PTRMAP_PAGENO returns the database page number of the pointer-map
+** page that stores the required pointer. PTRMAP_PTROFFSET returns
+** the offset of the requested map entry.
+**
+** If the pgno argument passed to PTRMAP_PAGENO is a pointer-map page,
+** then pgno is returned. So (pgno==PTRMAP_PAGENO(pgsz, pgno)) can be
+** used to test if pgno is a pointer-map page. PTRMAP_ISPAGE implements
+** this test.
+*/
+#define PTRMAP_PAGENO(pBt, pgno) ptrmapPageno(pBt, pgno)
+#define PTRMAP_PTROFFSET(pgptrmap, pgno) (5*(pgno-pgptrmap-1))
+#define PTRMAP_ISPAGE(pBt, pgno) (PTRMAP_PAGENO((pBt),(pgno))==(pgno))
+
+/*
+** The pointer map is a lookup table that identifies the parent page for
+** each child page in the database file.  The parent page is the page that
+** contains a pointer to the child.  Every page in the database contains
+** 0 or 1 parent pages.  (In this context 'database page' refers
+** to any page that is not part of the pointer map itself.)  Each pointer map
+** entry consists of a single byte 'type' and a 4 byte parent page number.
+** The PTRMAP_XXX identifiers below are the valid types.
+**
+** The purpose of the pointer map is to facility moving pages from one
+** position in the file to another as part of autovacuum.  When a page
+** is moved, the pointer in its parent must be updated to point to the
+** new location.  The pointer map is used to locate the parent page quickly.
+**
+** PTRMAP_ROOTPAGE: The database page is a root-page. The page-number is not
+**                  used in this case.
+**
+** PTRMAP_FREEPAGE: The database page is an unused (free) page. The page-number
+**                  is not used in this case.
+**
+** PTRMAP_OVERFLOW1: The database page is the first page in a list of
+**                   overflow pages. The page number identifies the page that
+**                   contains the cell with a pointer to this overflow page.
+**
+** PTRMAP_OVERFLOW2: The database page is the second or later page in a list of
+**                   overflow pages. The page-number identifies the previous
+**                   page in the overflow page list.
+**
+** PTRMAP_BTREE: The database page is a non-root btree page. The page number
+**               identifies the parent page in the btree.
+*/
+#define PTRMAP_ROOTPAGE 1
+#define PTRMAP_FREEPAGE 2
+#define PTRMAP_OVERFLOW1 3
+#define PTRMAP_OVERFLOW2 4
+#define PTRMAP_BTREE 5
+
+/* A bunch of assert() statements to check the transaction state variables
+** of handle p (type Btree*) are internally consistent.
+*/
+#define btreeIntegrity(p) \
+  assert( p->pBt->inTransaction!=TRANS_NONE || p->pBt->nTransaction==0 ); \
+  assert( p->pBt->inTransaction>=p->inTrans );
+
+
+/*
+** The ISAUTOVACUUM macro is used within balance_nonroot() to determine
+** if the database supports auto-vacuum or not. Because it is used
+** within an expression that is an argument to another macro
+** (sqliteMallocRaw), it is not possible to use conditional compilation.
+** So, this macro is defined instead.
+*/
+#ifndef SQLITE_OMIT_AUTOVACUUM
+#define ISAUTOVACUUM(pBt) (pBt->autoVacuum)
+#else
+#define ISAUTOVACUUM(pBt) 0
+#endif
+
+
+/*
+** This structure is passed around through all the PRAGMA integrity_check
+** checking routines in order to keep track of some global state information.
+**
+** The aRef[] array is allocated so that there is 1 bit for each page in
+** the database. As the integrity-check proceeds, for each page used in
+** the database the corresponding bit is set. This allows integrity-check to
+** detect pages that are used twice and orphaned pages (both of which
+** indicate corruption).
+*/
+typedef struct IntegrityCk IntegrityCk;
+struct IntegrityCk {
+  BtShared *pBt;    /* The tree being checked out */
+  Pager *pPager;    /* The associated pager.  Also accessible by pBt->pPager */
+  u8 *aPgRef;       /* 1 bit per page in the db (see above) */
+  Pgno nCkPage;     /* Pages in the database.  0 for partial check */
+  int mxErr;        /* Stop accumulating errors when this reaches zero */
+  int nErr;         /* Number of messages written to zErrMsg so far */
+  int rc;           /* SQLITE_OK, SQLITE_NOMEM, or SQLITE_INTERRUPT */
+  u32 nStep;        /* Number of steps into the integrity_check process */
+  const char *zPfx; /* Error message prefix */
+  Pgno v0;          /* Value for first %u substitution in zPfx (root page) */
+  Pgno v1;          /* Value for second %u substitution in zPfx (current pg) */
+  int v2;           /* Value for third %d substitution in zPfx */
+  StrAccum errMsg;  /* Accumulate the error message text here */
+  u32 *heap;        /* Min-heap used for analyzing cell coverage */
+  sqlite3 *db;      /* Database connection running the check */
+  i64 nRow;         /* Number of rows visited in current tree */
+};
+
+/*
+** Routines to read or write a two- and four-byte big-endian integer values.
+*/
+#define get2byte(x)   ((x)[0]<<8 | (x)[1])
+#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
+#define get4byte sqlite3Get4byte
+#define put4byte sqlite3Put4byte
+
+/*
+** get2byteAligned(), unlike get2byte(), requires that its argument point to a
+** two-byte aligned address.  get2byteAligned() is only used for accessing the
+** cell addresses in a btree header.
+*/
+#if SQLITE_BYTEORDER==4321
+# define get2byteAligned(x)  (*(u16*)(x))
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4008000
+# define get2byteAligned(x)  __builtin_bswap16(*(u16*)(x))
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+# define get2byteAligned(x)  _byteswap_ushort(*(u16*)(x))
+#else
+# define get2byteAligned(x)  ((x)[0]<<8 | (x)[1])
+#endif
+
+/************** End of btreeInt.h ********************************************/
+/************** Continuing where we left off in btmutex.c ********************/
+#ifndef SQLITE_OMIT_SHARED_CACHE
+#if SQLITE_THREADSAFE
+
+/*
+** Obtain the BtShared mutex associated with B-Tree handle p. Also,
+** set BtShared.db to the database handle associated with p and the
+** p->locked boolean to true.
+*/
+static void lockBtreeMutex(Btree *p){
+  assert( p->locked==0 );
+  assert( sqlite3_mutex_notheld(p->pBt->mutex) );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+
+  sqlite3_mutex_enter(p->pBt->mutex);
+  p->pBt->db = p->db;
+  p->locked = 1;
+}
+
+/*
+** Release the BtShared mutex associated with B-Tree handle p and
+** clear the p->locked boolean.
+*/
+static void SQLITE_NOINLINE unlockBtreeMutex(Btree *p){
+  BtShared *pBt = p->pBt;
+  assert( p->locked==1 );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  assert( p->db==pBt->db );
+
+  sqlite3_mutex_leave(pBt->mutex);
+  p->locked = 0;
+}
+
+/* Forward reference */
+static void SQLITE_NOINLINE btreeLockCarefully(Btree *p);
+
+/*
+** Enter a mutex on the given BTree object.
+**
+** If the object is not sharable, then no mutex is ever required
+** and this routine is a no-op.  The underlying mutex is non-recursive.
+** But we keep a reference count in Btree.wantToLock so the behavior
+** of this interface is recursive.
+**
+** To avoid deadlocks, multiple Btrees are locked in the same order
+** by all database connections.  The p->pNext is a list of other
+** Btrees belonging to the same database connection as the p Btree
+** which need to be locked after p.  If we cannot get a lock on
+** p, then first unlock all of the others on p->pNext, then wait
+** for the lock to become available on p, then relock all of the
+** subsequent Btrees that desire a lock.
+*/
+SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
+  /* Some basic sanity checking on the Btree.  The list of Btrees
+  ** connected by pNext and pPrev should be in sorted order by
+  ** Btree.pBt value. All elements of the list should belong to
+  ** the same connection. Only shared Btrees are on the list. */
+  assert( p->pNext==0 || p->pNext->pBt>p->pBt );
+  assert( p->pPrev==0 || p->pPrev->pBt<p->pBt );
+  assert( p->pNext==0 || p->pNext->db==p->db );
+  assert( p->pPrev==0 || p->pPrev->db==p->db );
+  assert( p->sharable || (p->pNext==0 && p->pPrev==0) );
+
+  /* Check for locking consistency */
+  assert( !p->locked || p->wantToLock>0 );
+  assert( p->sharable || p->wantToLock==0 );
+
+  /* We should already hold a lock on the database connection */
+  assert( sqlite3_mutex_held(p->db->mutex) );
+
+  /* Unless the database is sharable and unlocked, then BtShared.db
+  ** should already be set correctly. */
+  assert( (p->locked==0 && p->sharable) || p->pBt->db==p->db );
+
+  if( !p->sharable ) return;
+  p->wantToLock++;
+  if( p->locked ) return;
+  btreeLockCarefully(p);
+}
+
+/* This is a helper function for sqlite3BtreeLock(). By moving
+** complex, but seldom used logic, out of sqlite3BtreeLock() and
+** into this routine, we avoid unnecessary stack pointer changes
+** and thus help the sqlite3BtreeLock() routine to run much faster
+** in the common case.
+*/
+static void SQLITE_NOINLINE btreeLockCarefully(Btree *p){
+  Btree *pLater;
+
+  /* In most cases, we should be able to acquire the lock we
+  ** want without having to go through the ascending lock
+  ** procedure that follows.  Just be sure not to block.
+  */
+  if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
+    p->pBt->db = p->db;
+    p->locked = 1;
+    return;
+  }
+
+  /* To avoid deadlock, first release all locks with a larger
+  ** BtShared address.  Then acquire our lock.  Then reacquire
+  ** the other BtShared locks that we used to hold in ascending
+  ** order.
+  */
+  for(pLater=p->pNext; pLater; pLater=pLater->pNext){
+    assert( pLater->sharable );
+    assert( pLater->pNext==0 || pLater->pNext->pBt>pLater->pBt );
+    assert( !pLater->locked || pLater->wantToLock>0 );
+    if( pLater->locked ){
+      unlockBtreeMutex(pLater);
+    }
+  }
+  lockBtreeMutex(p);
+  for(pLater=p->pNext; pLater; pLater=pLater->pNext){
+    if( pLater->wantToLock ){
+      lockBtreeMutex(pLater);
+    }
+  }
+}
+
+
+/*
+** Exit the recursive mutex on a Btree.
+*/
+SQLITE_PRIVATE void sqlite3BtreeLeave(Btree *p){
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  if( p->sharable ){
+    assert( p->wantToLock>0 );
+    p->wantToLock--;
+    if( p->wantToLock==0 ){
+      unlockBtreeMutex(p);
+    }
+  }
+}
+
+#ifndef NDEBUG
+/*
+** Return true if the BtShared mutex is held on the btree, or if the
+** B-Tree is not marked as sharable.
+**
+** This routine is used only from within assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3BtreeHoldsMutex(Btree *p){
+  assert( p->sharable==0 || p->locked==0 || p->wantToLock>0 );
+  assert( p->sharable==0 || p->locked==0 || p->db==p->pBt->db );
+  assert( p->sharable==0 || p->locked==0 || sqlite3_mutex_held(p->pBt->mutex) );
+  assert( p->sharable==0 || p->locked==0 || sqlite3_mutex_held(p->db->mutex) );
+
+  return (p->sharable==0 || p->locked);
+}
+#endif
+
+
+/*
+** Enter the mutex on every Btree associated with a database
+** connection.  This is needed (for example) prior to parsing
+** a statement since we will be comparing table and column names
+** against all schemas and we do not want those schemas being
+** reset out from under us.
+**
+** There is a corresponding leave-all procedures.
+**
+** Enter the mutexes in ascending order by BtShared pointer address
+** to avoid the possibility of deadlock when two threads with
+** two or more btrees in common both try to lock all their btrees
+** at the same instant.
+*/
+static void SQLITE_NOINLINE btreeEnterAll(sqlite3 *db){
+  int i;
+  int skipOk = 1;
+  Btree *p;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nDb; i++){
+    p = db->aDb[i].pBt;
+    if( p && p->sharable ){
+      sqlite3BtreeEnter(p);
+      skipOk = 0;
+    }
+  }
+  db->noSharedCache = skipOk;
+}
+SQLITE_PRIVATE void sqlite3BtreeEnterAll(sqlite3 *db){
+  if( db->noSharedCache==0 ) btreeEnterAll(db);
+}
+static void SQLITE_NOINLINE btreeLeaveAll(sqlite3 *db){
+  int i;
+  Btree *p;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nDb; i++){
+    p = db->aDb[i].pBt;
+    if( p ) sqlite3BtreeLeave(p);
+  }
+}
+SQLITE_PRIVATE void sqlite3BtreeLeaveAll(sqlite3 *db){
+  if( db->noSharedCache==0 ) btreeLeaveAll(db);
+}
+
+#ifndef NDEBUG
+/*
+** Return true if the current thread holds the database connection
+** mutex and all required BtShared mutexes.
+**
+** This routine is used inside assert() statements only.
+*/
+SQLITE_PRIVATE int sqlite3BtreeHoldsAllMutexes(sqlite3 *db){
+  int i;
+  if( !sqlite3_mutex_held(db->mutex) ){
+    return 0;
+  }
+  for(i=0; i<db->nDb; i++){
+    Btree *p;
+    p = db->aDb[i].pBt;
+    if( p && p->sharable &&
+         (p->wantToLock==0 || !sqlite3_mutex_held(p->pBt->mutex)) ){
+      return 0;
+    }
+  }
+  return 1;
+}
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/*
+** Return true if the correct mutexes are held for accessing the
+** db->aDb[iDb].pSchema structure.  The mutexes required for schema
+** access are:
+**
+**   (1) The mutex on db
+**   (2) if iDb!=1, then the mutex on db->aDb[iDb].pBt.
+**
+** If pSchema is not NULL, then iDb is computed from pSchema and
+** db using sqlite3SchemaToIndex().
+*/
+SQLITE_PRIVATE int sqlite3SchemaMutexHeld(sqlite3 *db, int iDb, Schema *pSchema){
+  Btree *p;
+  assert( db!=0 );
+  if( db->pVfs==0 && db->nDb==0 ) return 1;
+  if( pSchema ) iDb = sqlite3SchemaToIndex(db, pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+  if( !sqlite3_mutex_held(db->mutex) ) return 0;
+  if( iDb==1 ) return 1;
+  p = db->aDb[iDb].pBt;
+  assert( p!=0 );
+  return p->sharable==0 || p->locked==1;
+}
+#endif /* NDEBUG */
+
+#else /* SQLITE_THREADSAFE>0 above.  SQLITE_THREADSAFE==0 below */
+/*
+** The following are special cases for mutex enter routines for use
+** in single threaded applications that use shared cache.  Except for
+** these two routines, all mutex operations are no-ops in that case and
+** are null #defines in btree.h.
+**
+** If shared cache is disabled, then all btree mutex routines, including
+** the ones below, are no-ops and are null #defines in btree.h.
+*/
+
+SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
+  p->pBt->db = p->db;
+}
+SQLITE_PRIVATE void sqlite3BtreeEnterAll(sqlite3 *db){
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Btree *p = db->aDb[i].pBt;
+    if( p ){
+      p->pBt->db = p->db;
+    }
+  }
+}
+#endif /* if SQLITE_THREADSAFE */
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** Enter a mutex on a Btree given a cursor owned by that Btree.
+**
+** These entry points are used by incremental I/O only. Enter() is required
+** any time OMIT_SHARED_CACHE is not defined, regardless of whether or not
+** the build is threadsafe. Leave() is only required by threadsafe builds.
+*/
+SQLITE_PRIVATE void sqlite3BtreeEnterCursor(BtCursor *pCur){
+  sqlite3BtreeEnter(pCur->pBtree);
+}
+# if SQLITE_THREADSAFE
+SQLITE_PRIVATE void sqlite3BtreeLeaveCursor(BtCursor *pCur){
+  sqlite3BtreeLeave(pCur->pBtree);
+}
+# endif
+#endif /* ifndef SQLITE_OMIT_INCRBLOB */
+
+#endif /* ifndef SQLITE_OMIT_SHARED_CACHE */
+
+/************** End of btmutex.c *********************************************/
+/************** Begin file btree.c *******************************************/
+/*
+** 2004 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements an external (disk-based) database using BTrees.
+** See the header comment on "btreeInt.h" for additional information.
+** Including a description of file format and an overview of operation.
+*/
+/* #include "btreeInt.h" */
+
+/*
+** The header string that appears at the beginning of every
+** SQLite database.
+*/
+static const char zMagicHeader[] = SQLITE_FILE_HEADER;
+
+/*
+** Set this global variable to 1 to enable tracing using the TRACE
+** macro.
+*/
+#if 0
+int sqlite3BtreeTrace=1;  /* True to enable tracing */
+# define TRACE(X)  if(sqlite3BtreeTrace){printf X;fflush(stdout);}
+#else
+# define TRACE(X)
+#endif
+
+/*
+** Extract a 2-byte big-endian integer from an array of unsigned bytes.
+** But if the value is zero, make it 65536.
+**
+** This routine is used to extract the "offset to cell content area" value
+** from the header of a btree page.  If the page size is 65536 and the page
+** is empty, the offset should be 65536, but the 2-byte value stores zero.
+** This routine makes the necessary adjustment to 65536.
+*/
+#define get2byteNotZero(X)  (((((int)get2byte(X))-1)&0xffff)+1)
+
+/*
+** Values passed as the 5th argument to allocateBtreePage()
+*/
+#define BTALLOC_ANY   0           /* Allocate any page */
+#define BTALLOC_EXACT 1           /* Allocate exact page if possible */
+#define BTALLOC_LE    2           /* Allocate any page <= the parameter */
+
+/*
+** Macro IfNotOmitAV(x) returns (x) if SQLITE_OMIT_AUTOVACUUM is not
+** defined, or 0 if it is. For example:
+**
+**   bIncrVacuum = IfNotOmitAV(pBtShared->incrVacuum);
+*/
+#ifndef SQLITE_OMIT_AUTOVACUUM
+#define IfNotOmitAV(expr) (expr)
+#else
+#define IfNotOmitAV(expr) 0
+#endif
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** A list of BtShared objects that are eligible for participation
+** in shared cache.  This variable has file scope during normal builds,
+** but the test harness needs to access it so we make it global for
+** test builds.
+**
+** Access to this variable is protected by SQLITE_MUTEX_STATIC_MAIN.
+*/
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
+#else
+static BtShared *SQLITE_WSD sqlite3SharedCacheList = 0;
+#endif
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Enable or disable the shared pager and schema features.
+**
+** This routine has no effect on existing database connections.
+** The shared cache setting effects only future calls to
+** sqlite3_open(), sqlite3_open16(), or sqlite3_open_v2().
+*/
+SQLITE_API int sqlite3_enable_shared_cache(int enable){
+  sqlite3GlobalConfig.sharedCacheEnabled = enable;
+  return SQLITE_OK;
+}
+#endif
+
+
+
+#ifdef SQLITE_OMIT_SHARED_CACHE
+  /*
+  ** The functions querySharedCacheTableLock(), setSharedCacheTableLock(),
+  ** and clearAllSharedCacheTableLocks()
+  ** manipulate entries in the BtShared.pLock linked list used to store
+  ** shared-cache table level locks. If the library is compiled with the
+  ** shared-cache feature disabled, then there is only ever one user
+  ** of each BtShared structure and so this locking is not necessary.
+  ** So define the lock related functions as no-ops.
+  */
+  #define querySharedCacheTableLock(a,b,c) SQLITE_OK
+  #define setSharedCacheTableLock(a,b,c) SQLITE_OK
+  #define clearAllSharedCacheTableLocks(a)
+  #define downgradeAllSharedCacheTableLocks(a)
+  #define hasSharedCacheTableLock(a,b,c,d) 1
+  #define hasReadConflicts(a, b) 0
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Return and reset the seek counter for a Btree object.
+*/
+SQLITE_PRIVATE sqlite3_uint64 sqlite3BtreeSeekCount(Btree *pBt){
+  u64 n =  pBt->nSeek;
+  pBt->nSeek = 0;
+  return n;
+}
+#endif
+
+/*
+** Implementation of the SQLITE_CORRUPT_PAGE() macro. Takes a single
+** (MemPage*) as an argument. The (MemPage*) must not be NULL.
+**
+** If SQLITE_DEBUG is not defined, then this macro is equivalent to
+** SQLITE_CORRUPT_BKPT. Or, if SQLITE_DEBUG is set, then the log message
+** normally produced as a side-effect of SQLITE_CORRUPT_BKPT is augmented
+** with the page number and filename associated with the (MemPage*).
+*/
+#ifdef SQLITE_DEBUG
+int corruptPageError(int lineno, MemPage *p){
+  char *zMsg;
+  sqlite3BeginBenignMalloc();
+  zMsg = sqlite3_mprintf("database corruption page %u of %s",
+             p->pgno, sqlite3PagerFilename(p->pBt->pPager, 0)
+  );
+  sqlite3EndBenignMalloc();
+  if( zMsg ){
+    sqlite3ReportError(SQLITE_CORRUPT, lineno, zMsg);
+  }
+  sqlite3_free(zMsg);
+  return SQLITE_CORRUPT_BKPT;
+}
+# define SQLITE_CORRUPT_PAGE(pMemPage) corruptPageError(__LINE__, pMemPage)
+#else
+# define SQLITE_CORRUPT_PAGE(pMemPage) SQLITE_CORRUPT_PGNO(pMemPage->pgno)
+#endif
+
+/* Default value for SHARED_LOCK_TRACE macro if shared-cache is disabled
+** or if the lock tracking is disabled.  This is always the value for
+** release builds.
+*/
+#define SHARED_LOCK_TRACE(X,MSG,TAB,TYPE)  /*no-op*/
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+
+#if 0
+/*  ^----  Change to 1 and recompile to enable shared-lock tracing
+**         for debugging purposes.
+**
+** Print all shared-cache locks on a BtShared.  Debugging use only.
+*/
+static void sharedLockTrace(
+  BtShared *pBt,
+  const char *zMsg,
+  int iRoot,
+  int eLockType
+){
+  BtLock *pLock;
+  if( iRoot>0 ){
+    printf("%s-%p %u%s:", zMsg, pBt, iRoot, eLockType==READ_LOCK?"R":"W");
+  }else{
+    printf("%s-%p:", zMsg, pBt);
+  }
+  for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
+    printf(" %p/%u%s", pLock->pBtree, pLock->iTable,
+           pLock->eLock==READ_LOCK ? "R" : "W");
+    while( pLock->pNext && pLock->pBtree==pLock->pNext->pBtree ){
+      pLock = pLock->pNext;
+      printf(",%u%s", pLock->iTable, pLock->eLock==READ_LOCK ? "R" : "W");
+    }
+  }
+  printf("\n");
+  fflush(stdout);
+}
+#undef SHARED_LOCK_TRACE
+#define SHARED_LOCK_TRACE(X,MSG,TAB,TYPE)  sharedLockTrace(X,MSG,TAB,TYPE)
+#endif /* Shared-lock tracing */
+
+#ifdef SQLITE_DEBUG
+/*
+**** This function is only used as part of an assert() statement. ***
+**
+** Check to see if pBtree holds the required locks to read or write to the
+** table with root page iRoot.   Return 1 if it does and 0 if not.
+**
+** For example, when writing to a table with root-page iRoot via
+** Btree connection pBtree:
+**
+**    assert( hasSharedCacheTableLock(pBtree, iRoot, 0, WRITE_LOCK) );
+**
+** When writing to an index that resides in a sharable database, the
+** caller should have first obtained a lock specifying the root page of
+** the corresponding table. This makes things a bit more complicated,
+** as this module treats each table as a separate structure. To determine
+** the table corresponding to the index being written, this
+** function has to search through the database schema.
+**
+** Instead of a lock on the table/index rooted at page iRoot, the caller may
+** hold a write-lock on the schema table (root page 1). This is also
+** acceptable.
+*/
+static int hasSharedCacheTableLock(
+  Btree *pBtree,         /* Handle that must hold lock */
+  Pgno iRoot,            /* Root page of b-tree */
+  int isIndex,           /* True if iRoot is the root of an index b-tree */
+  int eLockType          /* Required lock type (READ_LOCK or WRITE_LOCK) */
+){
+  Schema *pSchema = (Schema *)pBtree->pBt->pSchema;
+  Pgno iTab = 0;
+  BtLock *pLock;
+
+  /* If this database is not shareable, or if the client is reading
+  ** and has the read-uncommitted flag set, then no lock is required.
+  ** Return true immediately.
+  */
+  if( (pBtree->sharable==0)
+   || (eLockType==READ_LOCK && (pBtree->db->flags & SQLITE_ReadUncommit))
+  ){
+    return 1;
+  }
+
+  /* If the client is reading  or writing an index and the schema is
+  ** not loaded, then it is too difficult to actually check to see if
+  ** the correct locks are held.  So do not bother - just return true.
+  ** This case does not come up very often anyhow.
+  */
+  if( isIndex && (!pSchema || (pSchema->schemaFlags&DB_SchemaLoaded)==0) ){
+    return 1;
+  }
+
+  /* Figure out the root-page that the lock should be held on. For table
+  ** b-trees, this is just the root page of the b-tree being read or
+  ** written. For index b-trees, it is the root page of the associated
+  ** table.  */
+  if( isIndex ){
+    HashElem *p;
+    int bSeen = 0;
+    for(p=sqliteHashFirst(&pSchema->idxHash); p; p=sqliteHashNext(p)){
+      Index *pIdx = (Index *)sqliteHashData(p);
+      if( pIdx->tnum==iRoot ){
+        if( bSeen ){
+          /* Two or more indexes share the same root page.  There must
+          ** be imposter tables.  So just return true.  The assert is not
+          ** useful in that case. */
+          return 1;
+        }
+        iTab = pIdx->pTable->tnum;
+        bSeen = 1;
+      }
+    }
+  }else{
+    iTab = iRoot;
+  }
+
+  SHARED_LOCK_TRACE(pBtree->pBt,"hasLock",iRoot,eLockType);
+
+  /* Search for the required lock. Either a write-lock on root-page iTab, a
+  ** write-lock on the schema table, or (if the client is reading) a
+  ** read-lock on iTab will suffice. Return 1 if any of these are found.  */
+  for(pLock=pBtree->pBt->pLock; pLock; pLock=pLock->pNext){
+    if( pLock->pBtree==pBtree
+     && (pLock->iTable==iTab || (pLock->eLock==WRITE_LOCK && pLock->iTable==1))
+     && pLock->eLock>=eLockType
+    ){
+      return 1;
+    }
+  }
+
+  /* Failed to find the required lock. */
+  return 0;
+}
+#endif /* SQLITE_DEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+**** This function may be used as part of assert() statements only. ****
+**
+** Return true if it would be illegal for pBtree to write into the
+** table or index rooted at iRoot because other shared connections are
+** simultaneously reading that same table or index.
+**
+** It is illegal for pBtree to write if some other Btree object that
+** shares the same BtShared object is currently reading or writing
+** the iRoot table.  Except, if the other Btree object has the
+** read-uncommitted flag set, then it is OK for the other object to
+** have a read cursor.
+**
+** For example, before writing to any part of the table or index
+** rooted at page iRoot, one should call:
+**
+**    assert( !hasReadConflicts(pBtree, iRoot) );
+*/
+static int hasReadConflicts(Btree *pBtree, Pgno iRoot){
+  BtCursor *p;
+  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
+    if( p->pgnoRoot==iRoot
+     && p->pBtree!=pBtree
+     && 0==(p->pBtree->db->flags & SQLITE_ReadUncommit)
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+#endif    /* #ifdef SQLITE_DEBUG */
+
+/*
+** Query to see if Btree handle p may obtain a lock of type eLock
+** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
+** SQLITE_OK if the lock may be obtained (by calling
+** setSharedCacheTableLock()), or SQLITE_LOCKED if not.
+*/
+static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){
+  BtShared *pBt = p->pBt;
+  BtLock *pIter;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
+  assert( p->db!=0 );
+  assert( !(p->db->flags&SQLITE_ReadUncommit)||eLock==WRITE_LOCK||iTab==1 );
+
+  /* If requesting a write-lock, then the Btree must have an open write
+  ** transaction on this file. And, obviously, for this to be so there
+  ** must be an open write transaction on the file itself.
+  */
+  assert( eLock==READ_LOCK || (p==pBt->pWriter && p->inTrans==TRANS_WRITE) );
+  assert( eLock==READ_LOCK || pBt->inTransaction==TRANS_WRITE );
+
+  /* This routine is a no-op if the shared-cache is not enabled */
+  if( !p->sharable ){
+    return SQLITE_OK;
+  }
+
+  /* If some other connection is holding an exclusive lock, the
+  ** requested lock may not be obtained.
+  */
+  if( pBt->pWriter!=p && (pBt->btsFlags & BTS_EXCLUSIVE)!=0 ){
+    sqlite3ConnectionBlocked(p->db, pBt->pWriter->db);
+    return SQLITE_LOCKED_SHAREDCACHE;
+  }
+
+  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+    /* The condition (pIter->eLock!=eLock) in the following if(...)
+    ** statement is a simplification of:
+    **
+    **   (eLock==WRITE_LOCK || pIter->eLock==WRITE_LOCK)
+    **
+    ** since we know that if eLock==WRITE_LOCK, then no other connection
+    ** may hold a WRITE_LOCK on any table in this file (since there can
+    ** only be a single writer).
+    */
+    assert( pIter->eLock==READ_LOCK || pIter->eLock==WRITE_LOCK );
+    assert( eLock==READ_LOCK || pIter->pBtree==p || pIter->eLock==READ_LOCK);
+    if( pIter->pBtree!=p && pIter->iTable==iTab && pIter->eLock!=eLock ){
+      sqlite3ConnectionBlocked(p->db, pIter->pBtree->db);
+      if( eLock==WRITE_LOCK ){
+        assert( p==pBt->pWriter );
+        pBt->btsFlags |= BTS_PENDING;
+      }
+      return SQLITE_LOCKED_SHAREDCACHE;
+    }
+  }
+  return SQLITE_OK;
+}
+#endif /* !SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Add a lock on the table with root-page iTable to the shared-btree used
+** by Btree handle p. Parameter eLock must be either READ_LOCK or
+** WRITE_LOCK.
+**
+** This function assumes the following:
+**
+**   (a) The specified Btree object p is connected to a sharable
+**       database (one with the BtShared.sharable flag set), and
+**
+**   (b) No other Btree objects hold a lock that conflicts
+**       with the requested lock (i.e. querySharedCacheTableLock() has
+**       already been called and returned SQLITE_OK).
+**
+** SQLITE_OK is returned if the lock is added successfully. SQLITE_NOMEM
+** is returned if a malloc attempt fails.
+*/
+static int setSharedCacheTableLock(Btree *p, Pgno iTable, u8 eLock){
+  BtShared *pBt = p->pBt;
+  BtLock *pLock = 0;
+  BtLock *pIter;
+
+  SHARED_LOCK_TRACE(pBt,"setLock", iTable, eLock);
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
+  assert( p->db!=0 );
+
+  /* A connection with the read-uncommitted flag set will never try to
+  ** obtain a read-lock using this function. The only read-lock obtained
+  ** by a connection in read-uncommitted mode is on the sqlite_schema
+  ** table, and that lock is obtained in BtreeBeginTrans().  */
+  assert( 0==(p->db->flags&SQLITE_ReadUncommit) || eLock==WRITE_LOCK );
+
+  /* This function should only be called on a sharable b-tree after it
+  ** has been determined that no other b-tree holds a conflicting lock.  */
+  assert( p->sharable );
+  assert( SQLITE_OK==querySharedCacheTableLock(p, iTable, eLock) );
+
+  /* First search the list for an existing lock on this table. */
+  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+    if( pIter->iTable==iTable && pIter->pBtree==p ){
+      pLock = pIter;
+      break;
+    }
+  }
+
+  /* If the above search did not find a BtLock struct associating Btree p
+  ** with table iTable, allocate one and link it into the list.
+  */
+  if( !pLock ){
+    pLock = (BtLock *)sqlite3MallocZero(sizeof(BtLock));
+    if( !pLock ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    pLock->iTable = iTable;
+    pLock->pBtree = p;
+    pLock->pNext = pBt->pLock;
+    pBt->pLock = pLock;
+  }
+
+  /* Set the BtLock.eLock variable to the maximum of the current lock
+  ** and the requested lock. This means if a write-lock was already held
+  ** and a read-lock requested, we don't incorrectly downgrade the lock.
+  */
+  assert( WRITE_LOCK>READ_LOCK );
+  if( eLock>pLock->eLock ){
+    pLock->eLock = eLock;
+  }
+
+  return SQLITE_OK;
+}
+#endif /* !SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Release all the table locks (locks obtained via calls to
+** the setSharedCacheTableLock() procedure) held by Btree object p.
+**
+** This function assumes that Btree p has an open read or write
+** transaction. If it does not, then the BTS_PENDING flag
+** may be incorrectly cleared.
+*/
+static void clearAllSharedCacheTableLocks(Btree *p){
+  BtShared *pBt = p->pBt;
+  BtLock **ppIter = &pBt->pLock;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( p->sharable || 0==*ppIter );
+  assert( p->inTrans>0 );
+
+  SHARED_LOCK_TRACE(pBt, "clearAllLocks", 0, 0);
+
+  while( *ppIter ){
+    BtLock *pLock = *ppIter;
+    assert( (pBt->btsFlags & BTS_EXCLUSIVE)==0 || pBt->pWriter==pLock->pBtree );
+    assert( pLock->pBtree->inTrans>=pLock->eLock );
+    if( pLock->pBtree==p ){
+      *ppIter = pLock->pNext;
+      assert( pLock->iTable!=1 || pLock==&p->lock );
+      if( pLock->iTable!=1 ){
+        sqlite3_free(pLock);
+      }
+    }else{
+      ppIter = &pLock->pNext;
+    }
+  }
+
+  assert( (pBt->btsFlags & BTS_PENDING)==0 || pBt->pWriter );
+  if( pBt->pWriter==p ){
+    pBt->pWriter = 0;
+    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
+  }else if( pBt->nTransaction==2 ){
+    /* This function is called when Btree p is concluding its
+    ** transaction. If there currently exists a writer, and p is not
+    ** that writer, then the number of locks held by connections other
+    ** than the writer must be about to drop to zero. In this case
+    ** set the BTS_PENDING flag to 0.
+    **
+    ** If there is not currently a writer, then BTS_PENDING must
+    ** be zero already. So this next line is harmless in that case.
+    */
+    pBt->btsFlags &= ~BTS_PENDING;
+  }
+}
+
+/*
+** This function changes all write-locks held by Btree p into read-locks.
+*/
+static void downgradeAllSharedCacheTableLocks(Btree *p){
+  BtShared *pBt = p->pBt;
+
+  SHARED_LOCK_TRACE(pBt, "downgradeLocks", 0, 0);
+
+  if( pBt->pWriter==p ){
+    BtLock *pLock;
+    pBt->pWriter = 0;
+    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
+    for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
+      assert( pLock->eLock==READ_LOCK || pLock->pBtree==p );
+      pLock->eLock = READ_LOCK;
+    }
+  }
+}
+
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+
+static void releasePage(MemPage *pPage);         /* Forward reference */
+static void releasePageOne(MemPage *pPage);      /* Forward reference */
+static void releasePageNotNull(MemPage *pPage);  /* Forward reference */
+
+/*
+***** This routine is used inside of assert() only ****
+**
+** Verify that the cursor holds the mutex on its BtShared
+*/
+#ifdef SQLITE_DEBUG
+static int cursorHoldsMutex(BtCursor *p){
+  return sqlite3_mutex_held(p->pBt->mutex);
+}
+
+/* Verify that the cursor and the BtShared agree about what is the current
+** database connetion. This is important in shared-cache mode. If the database
+** connection pointers get out-of-sync, it is possible for routines like
+** btreeInitPage() to reference an stale connection pointer that references a
+** a connection that has already closed.  This routine is used inside assert()
+** statements only and for the purpose of double-checking that the btree code
+** does keep the database connection pointers up-to-date.
+*/
+static int cursorOwnsBtShared(BtCursor *p){
+  assert( cursorHoldsMutex(p) );
+  return (p->pBtree->db==p->pBt->db);
+}
+#endif
+
+/*
+** Invalidate the overflow cache of the cursor passed as the first argument.
+** on the shared btree structure pBt.
+*/
+#define invalidateOverflowCache(pCur) (pCur->curFlags &= ~BTCF_ValidOvfl)
+
+/*
+** Invalidate the overflow page-list cache for all cursors opened
+** on the shared btree structure pBt.
+*/
+static void invalidateAllOverflowCache(BtShared *pBt){
+  BtCursor *p;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  for(p=pBt->pCursor; p; p=p->pNext){
+    invalidateOverflowCache(p);
+  }
+}
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** This function is called before modifying the contents of a table
+** to invalidate any incrblob cursors that are open on the
+** row or one of the rows being modified.
+**
+** If argument isClearTable is true, then the entire contents of the
+** table is about to be deleted. In this case invalidate all incrblob
+** cursors open on any row within the table with root-page pgnoRoot.
+**
+** Otherwise, if argument isClearTable is false, then the row with
+** rowid iRow is being replaced or deleted. In this case invalidate
+** only those incrblob cursors open on that specific row.
+*/
+static void invalidateIncrblobCursors(
+  Btree *pBtree,          /* The database file to check */
+  Pgno pgnoRoot,          /* The table that might be changing */
+  i64 iRow,               /* The rowid that might be changing */
+  int isClearTable        /* True if all rows are being deleted */
+){
+  BtCursor *p;
+  assert( pBtree->hasIncrblobCur );
+  assert( sqlite3BtreeHoldsMutex(pBtree) );
+  pBtree->hasIncrblobCur = 0;
+  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
+    if( (p->curFlags & BTCF_Incrblob)!=0 ){
+      pBtree->hasIncrblobCur = 1;
+      if( p->pgnoRoot==pgnoRoot && (isClearTable || p->info.nKey==iRow) ){
+        p->eState = CURSOR_INVALID;
+      }
+    }
+  }
+}
+
+#else
+  /* Stub function when INCRBLOB is omitted */
+  #define invalidateIncrblobCursors(w,x,y,z)
+#endif /* SQLITE_OMIT_INCRBLOB */
+
+/*
+** Set bit pgno of the BtShared.pHasContent bitvec. This is called
+** when a page that previously contained data becomes a free-list leaf
+** page.
+**
+** The BtShared.pHasContent bitvec exists to work around an obscure
+** bug caused by the interaction of two useful IO optimizations surrounding
+** free-list leaf pages:
+**
+**   1) When all data is deleted from a page and the page becomes
+**      a free-list leaf page, the page is not written to the database
+**      (as free-list leaf pages contain no meaningful data). Sometimes
+**      such a page is not even journalled (as it will not be modified,
+**      why bother journalling it?).
+**
+**   2) When a free-list leaf page is reused, its content is not read
+**      from the database or written to the journal file (why should it
+**      be, if it is not at all meaningful?).
+**
+** By themselves, these optimizations work fine and provide a handy
+** performance boost to bulk delete or insert operations. However, if
+** a page is moved to the free-list and then reused within the same
+** transaction, a problem comes up. If the page is not journalled when
+** it is moved to the free-list and it is also not journalled when it
+** is extracted from the free-list and reused, then the original data
+** may be lost. In the event of a rollback, it may not be possible
+** to restore the database to its original configuration.
+**
+** The solution is the BtShared.pHasContent bitvec. Whenever a page is
+** moved to become a free-list leaf page, the corresponding bit is
+** set in the bitvec. Whenever a leaf page is extracted from the free-list,
+** optimization 2 above is omitted if the corresponding bit is already
+** set in BtShared.pHasContent. The contents of the bitvec are cleared
+** at the end of every transaction.
+*/
+static int btreeSetHasContent(BtShared *pBt, Pgno pgno){
+  int rc = SQLITE_OK;
+  if( !pBt->pHasContent ){
+    assert( pgno<=pBt->nPage );
+    pBt->pHasContent = sqlite3BitvecCreate(pBt->nPage);
+    if( !pBt->pHasContent ){
+      rc = SQLITE_NOMEM_BKPT;
+    }
+  }
+  if( rc==SQLITE_OK && pgno<=sqlite3BitvecSize(pBt->pHasContent) ){
+    rc = sqlite3BitvecSet(pBt->pHasContent, pgno);
+  }
+  return rc;
+}
+
+/*
+** Query the BtShared.pHasContent vector.
+**
+** This function is called when a free-list leaf page is removed from the
+** free-list for reuse. It returns false if it is safe to retrieve the
+** page from the pager layer with the 'no-content' flag set. True otherwise.
+*/
+static int btreeGetHasContent(BtShared *pBt, Pgno pgno){
+  Bitvec *p = pBt->pHasContent;
+  return p && (pgno>sqlite3BitvecSize(p) || sqlite3BitvecTestNotNull(p, pgno));
+}
+
+/*
+** Clear (destroy) the BtShared.pHasContent bitvec. This should be
+** invoked at the conclusion of each write-transaction.
+*/
+static void btreeClearHasContent(BtShared *pBt){
+  sqlite3BitvecDestroy(pBt->pHasContent);
+  pBt->pHasContent = 0;
+}
+
+/*
+** Release all of the apPage[] pages for a cursor.
+*/
+static void btreeReleaseAllCursorPages(BtCursor *pCur){
+  int i;
+  if( pCur->iPage>=0 ){
+    for(i=0; i<pCur->iPage; i++){
+      releasePageNotNull(pCur->apPage[i]);
+    }
+    releasePageNotNull(pCur->pPage);
+    pCur->iPage = -1;
+  }
+}
+
+/*
+** The cursor passed as the only argument must point to a valid entry
+** when this function is called (i.e. have eState==CURSOR_VALID). This
+** function saves the current cursor key in variables pCur->nKey and
+** pCur->pKey. SQLITE_OK is returned if successful or an SQLite error
+** code otherwise.
+**
+** If the cursor is open on an intkey table, then the integer key
+** (the rowid) is stored in pCur->nKey and pCur->pKey is left set to
+** NULL. If the cursor is open on a non-intkey table, then pCur->pKey is
+** set to point to a malloced buffer pCur->nKey bytes in size containing
+** the key.
+*/
+static int saveCursorKey(BtCursor *pCur){
+  int rc = SQLITE_OK;
+  assert( CURSOR_VALID==pCur->eState );
+  assert( 0==pCur->pKey );
+  assert( cursorHoldsMutex(pCur) );
+
+  if( pCur->curIntKey ){
+    /* Only the rowid is required for a table btree */
+    pCur->nKey = sqlite3BtreeIntegerKey(pCur);
+  }else{
+    /* For an index btree, save the complete key content. It is possible
+    ** that the current key is corrupt. In that case, it is possible that
+    ** the sqlite3VdbeRecordUnpack() function may overread the buffer by
+    ** up to the size of 1 varint plus 1 8-byte value when the cursor
+    ** position is restored. Hence the 17 bytes of padding allocated
+    ** below. */
+    void *pKey;
+    pCur->nKey = sqlite3BtreePayloadSize(pCur);
+    pKey = sqlite3Malloc( pCur->nKey + 9 + 8 );
+    if( pKey ){
+      rc = sqlite3BtreePayload(pCur, 0, (int)pCur->nKey, pKey);
+      if( rc==SQLITE_OK ){
+        memset(((u8*)pKey)+pCur->nKey, 0, 9+8);
+        pCur->pKey = pKey;
+      }else{
+        sqlite3_free(pKey);
+      }
+    }else{
+      rc = SQLITE_NOMEM_BKPT;
+    }
+  }
+  assert( !pCur->curIntKey || !pCur->pKey );
+  return rc;
+}
+
+/*
+** Save the current cursor position in the variables BtCursor.nKey
+** and BtCursor.pKey. The cursor's state is set to CURSOR_REQUIRESEEK.
+**
+** The caller must ensure that the cursor is valid (has eState==CURSOR_VALID)
+** prior to calling this routine.
+*/
+static int saveCursorPosition(BtCursor *pCur){
+  int rc;
+
+  assert( CURSOR_VALID==pCur->eState || CURSOR_SKIPNEXT==pCur->eState );
+  assert( 0==pCur->pKey );
+  assert( cursorHoldsMutex(pCur) );
+
+  if( pCur->curFlags & BTCF_Pinned ){
+    return SQLITE_CONSTRAINT_PINNED;
+  }
+  if( pCur->eState==CURSOR_SKIPNEXT ){
+    pCur->eState = CURSOR_VALID;
+  }else{
+    pCur->skipNext = 0;
+  }
+
+  rc = saveCursorKey(pCur);
+  if( rc==SQLITE_OK ){
+    btreeReleaseAllCursorPages(pCur);
+    pCur->eState = CURSOR_REQUIRESEEK;
+  }
+
+  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl|BTCF_AtLast);
+  return rc;
+}
+
+/* Forward reference */
+static int SQLITE_NOINLINE saveCursorsOnList(BtCursor*,Pgno,BtCursor*);
+
+/*
+** Save the positions of all cursors (except pExcept) that are open on
+** the table with root-page iRoot.  "Saving the cursor position" means that
+** the location in the btree is remembered in such a way that it can be
+** moved back to the same spot after the btree has been modified.  This
+** routine is called just before cursor pExcept is used to modify the
+** table, for example in BtreeDelete() or BtreeInsert().
+**
+** If there are two or more cursors on the same btree, then all such
+** cursors should have their BTCF_Multiple flag set.  The btreeCursor()
+** routine enforces that rule.  This routine only needs to be called in
+** the uncommon case when pExpect has the BTCF_Multiple flag set.
+**
+** If pExpect!=NULL and if no other cursors are found on the same root-page,
+** then the BTCF_Multiple flag on pExpect is cleared, to avoid another
+** pointless call to this routine.
+**
+** Implementation note:  This routine merely checks to see if any cursors
+** need to be saved.  It calls out to saveCursorsOnList() in the (unusual)
+** event that cursors are in need to being saved.
+*/
+static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
+  BtCursor *p;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pExcept==0 || pExcept->pBt==pBt );
+  for(p=pBt->pCursor; p; p=p->pNext){
+    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ) break;
+  }
+  if( p ) return saveCursorsOnList(p, iRoot, pExcept);
+  if( pExcept ) pExcept->curFlags &= ~BTCF_Multiple;
+  return SQLITE_OK;
+}
+
+/* This helper routine to saveAllCursors does the actual work of saving
+** the cursors if and when a cursor is found that actually requires saving.
+** The common case is that no cursors need to be saved, so this routine is
+** broken out from its caller to avoid unnecessary stack pointer movement.
+*/
+static int SQLITE_NOINLINE saveCursorsOnList(
+  BtCursor *p,         /* The first cursor that needs saving */
+  Pgno iRoot,          /* Only save cursor with this iRoot. Save all if zero */
+  BtCursor *pExcept    /* Do not save this cursor */
+){
+  do{
+    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ){
+      if( p->eState==CURSOR_VALID || p->eState==CURSOR_SKIPNEXT ){
+        int rc = saveCursorPosition(p);
+        if( SQLITE_OK!=rc ){
+          return rc;
+        }
+      }else{
+        testcase( p->iPage>=0 );
+        btreeReleaseAllCursorPages(p);
+      }
+    }
+    p = p->pNext;
+  }while( p );
+  return SQLITE_OK;
+}
+
+/*
+** Clear the current cursor position.
+*/
+SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  sqlite3_free(pCur->pKey);
+  pCur->pKey = 0;
+  pCur->eState = CURSOR_INVALID;
+}
+
+/*
+** In this version of BtreeMoveto, pKey is a packed index record
+** such as is generated by the OP_MakeRecord opcode.  Unpack the
+** record and then call sqlite3BtreeIndexMoveto() to do the work.
+*/
+static int btreeMoveto(
+  BtCursor *pCur,     /* Cursor open on the btree to be searched */
+  const void *pKey,   /* Packed key if the btree is an index */
+  i64 nKey,           /* Integer key for tables.  Size of pKey for indices */
+  int bias,           /* Bias search to the high end */
+  int *pRes           /* Write search results here */
+){
+  int rc;                    /* Status code */
+  UnpackedRecord *pIdxKey;   /* Unpacked index key */
+
+  if( pKey ){
+    KeyInfo *pKeyInfo = pCur->pKeyInfo;
+    assert( nKey==(i64)(int)nKey );
+    pIdxKey = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
+    if( pIdxKey==0 ) return SQLITE_NOMEM_BKPT;
+    sqlite3VdbeRecordUnpack(pKeyInfo, (int)nKey, pKey, pIdxKey);
+    if( pIdxKey->nField==0 || pIdxKey->nField>pKeyInfo->nAllField ){
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      rc = sqlite3BtreeIndexMoveto(pCur, pIdxKey, pRes);
+    }
+    sqlite3DbFree(pCur->pKeyInfo->db, pIdxKey);
+  }else{
+    pIdxKey = 0;
+    rc = sqlite3BtreeTableMoveto(pCur, nKey, bias, pRes);
+  }
+  return rc;
+}
+
+/*
+** Restore the cursor to the position it was in (or as close to as possible)
+** when saveCursorPosition() was called. Note that this call deletes the
+** saved position info stored by saveCursorPosition(), so there can be
+** at most one effective restoreCursorPosition() call after each
+** saveCursorPosition().
+*/
+static int btreeRestoreCursorPosition(BtCursor *pCur){
+  int rc;
+  int skipNext = 0;
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState>=CURSOR_REQUIRESEEK );
+  if( pCur->eState==CURSOR_FAULT ){
+    return pCur->skipNext;
+  }
+  pCur->eState = CURSOR_INVALID;
+  if( sqlite3FaultSim(410) ){
+    rc = SQLITE_IOERR;
+  }else{
+    rc = btreeMoveto(pCur, pCur->pKey, pCur->nKey, 0, &skipNext);
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3_free(pCur->pKey);
+    pCur->pKey = 0;
+    assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_INVALID );
+    if( skipNext ) pCur->skipNext = skipNext;
+    if( pCur->skipNext && pCur->eState==CURSOR_VALID ){
+      pCur->eState = CURSOR_SKIPNEXT;
+    }
+  }
+  return rc;
+}
+
+#define restoreCursorPosition(p) \
+  (p->eState>=CURSOR_REQUIRESEEK ? \
+         btreeRestoreCursorPosition(p) : \
+         SQLITE_OK)
+
+/*
+** Determine whether or not a cursor has moved from the position where
+** it was last placed, or has been invalidated for any other reason.
+** Cursors can move when the row they are pointing at is deleted out
+** from under them, for example.  Cursor might also move if a btree
+** is rebalanced.
+**
+** Calling this routine with a NULL cursor pointer returns false.
+**
+** Use the separate sqlite3BtreeCursorRestore() routine to restore a cursor
+** back to where it ought to be if this routine returns true.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor *pCur){
+  assert( EIGHT_BYTE_ALIGNMENT(pCur)
+       || pCur==sqlite3BtreeFakeValidCursor() );
+  assert( offsetof(BtCursor, eState)==0 );
+  assert( sizeof(pCur->eState)==1 );
+  return CURSOR_VALID != *(u8*)pCur;
+}
+
+/*
+** Return a pointer to a fake BtCursor object that will always answer
+** false to the sqlite3BtreeCursorHasMoved() routine above.  The fake
+** cursor returned must not be used with any other Btree interface.
+*/
+SQLITE_PRIVATE BtCursor *sqlite3BtreeFakeValidCursor(void){
+  static u8 fakeCursor = CURSOR_VALID;
+  assert( offsetof(BtCursor, eState)==0 );
+  return (BtCursor*)&fakeCursor;
+}
+
+/*
+** This routine restores a cursor back to its original position after it
+** has been moved by some outside activity (such as a btree rebalance or
+** a row having been deleted out from under the cursor).
+**
+** On success, the *pDifferentRow parameter is false if the cursor is left
+** pointing at exactly the same row.  *pDifferntRow is the row the cursor
+** was pointing to has been deleted, forcing the cursor to point to some
+** nearby row.
+**
+** This routine should only be called for a cursor that just returned
+** TRUE from sqlite3BtreeCursorHasMoved().
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorRestore(BtCursor *pCur, int *pDifferentRow){
+  int rc;
+
+  assert( pCur!=0 );
+  assert( pCur->eState!=CURSOR_VALID );
+  rc = restoreCursorPosition(pCur);
+  if( rc ){
+    *pDifferentRow = 1;
+    return rc;
+  }
+  if( pCur->eState!=CURSOR_VALID ){
+    *pDifferentRow = 1;
+  }else{
+    *pDifferentRow = 0;
+  }
+  return SQLITE_OK;
+}
+
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/*
+** Provide hints to the cursor.  The particular hint given (and the type
+** and number of the varargs parameters) is determined by the eHintType
+** parameter.  See the definitions of the BTREE_HINT_* macros for details.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorHint(BtCursor *pCur, int eHintType, ...){
+  /* Used only by system that substitute their own storage engine */
+#ifdef SQLITE_DEBUG
+  if( ALWAYS(eHintType==BTREE_HINT_RANGE) ){
+    va_list ap;
+    Expr *pExpr;
+    Walker w;
+    memset(&w, 0, sizeof(w));
+    w.xExprCallback = sqlite3CursorRangeHintExprCheck;
+    va_start(ap, eHintType);
+    pExpr = va_arg(ap, Expr*);
+    w.u.aMem = va_arg(ap, Mem*);
+    va_end(ap);
+    assert( pExpr!=0 );
+    assert( w.u.aMem!=0 );
+    sqlite3WalkExpr(&w, pExpr);
+  }
+#endif /* SQLITE_DEBUG */
+}
+#endif /* SQLITE_ENABLE_CURSOR_HINTS */
+
+
+/*
+** Provide flag hints to the cursor.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorHintFlags(BtCursor *pCur, unsigned x){
+  assert( x==BTREE_SEEK_EQ || x==BTREE_BULKLOAD || x==0 );
+  pCur->hints = x;
+}
+
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Given a page number of a regular database page, return the page
+** number for the pointer-map page that contains the entry for the
+** input page number.
+**
+** Return 0 (not a valid page) for pgno==1 since there is
+** no pointer map associated with page 1.  The integrity_check logic
+** requires that ptrmapPageno(*,1)!=1.
+*/
+static Pgno ptrmapPageno(BtShared *pBt, Pgno pgno){
+  int nPagesPerMapPage;
+  Pgno iPtrMap, ret;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pgno<2 ) return 0;
+  nPagesPerMapPage = (pBt->usableSize/5)+1;
+  iPtrMap = (pgno-2)/nPagesPerMapPage;
+  ret = (iPtrMap*nPagesPerMapPage) + 2;
+  if( ret==PENDING_BYTE_PAGE(pBt) ){
+    ret++;
+  }
+  return ret;
+}
+
+/*
+** Write an entry into the pointer map.
+**
+** This routine updates the pointer map entry for page number 'key'
+** so that it maps to type 'eType' and parent page number 'pgno'.
+**
+** If *pRC is initially non-zero (non-SQLITE_OK) then this routine is
+** a no-op.  If an error occurs, the appropriate error code is written
+** into *pRC.
+*/
+static void ptrmapPut(BtShared *pBt, Pgno key, u8 eType, Pgno parent, int *pRC){
+  DbPage *pDbPage;  /* The pointer map page */
+  u8 *pPtrmap;      /* The pointer map data */
+  Pgno iPtrmap;     /* The pointer map page number */
+  int offset;       /* Offset in pointer map page */
+  int rc;           /* Return code from subfunctions */
+
+  if( *pRC ) return;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  /* The super-journal page number must never be used as a pointer map page */
+  assert( 0==PTRMAP_ISPAGE(pBt, PENDING_BYTE_PAGE(pBt)) );
+
+  assert( pBt->autoVacuum );
+  if( key==0 ){
+    *pRC = SQLITE_CORRUPT_BKPT;
+    return;
+  }
+  iPtrmap = PTRMAP_PAGENO(pBt, key);
+  rc = sqlite3PagerGet(pBt->pPager, iPtrmap, &pDbPage, 0);
+  if( rc!=SQLITE_OK ){
+    *pRC = rc;
+    return;
+  }
+  if( ((char*)sqlite3PagerGetExtra(pDbPage))[0]!=0 ){
+    /* The first byte of the extra data is the MemPage.isInit byte.
+    ** If that byte is set, it means this page is also being used
+    ** as a btree page. */
+    *pRC = SQLITE_CORRUPT_BKPT;
+    goto ptrmap_exit;
+  }
+  offset = PTRMAP_PTROFFSET(iPtrmap, key);
+  if( offset<0 ){
+    *pRC = SQLITE_CORRUPT_BKPT;
+    goto ptrmap_exit;
+  }
+  assert( offset <= (int)pBt->usableSize-5 );
+  pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
+
+  if( eType!=pPtrmap[offset] || get4byte(&pPtrmap[offset+1])!=parent ){
+    TRACE(("PTRMAP_UPDATE: %u->(%u,%u)\n", key, eType, parent));
+    *pRC= rc = sqlite3PagerWrite(pDbPage);
+    if( rc==SQLITE_OK ){
+      pPtrmap[offset] = eType;
+      put4byte(&pPtrmap[offset+1], parent);
+    }
+  }
+
+ptrmap_exit:
+  sqlite3PagerUnref(pDbPage);
+}
+
+/*
+** Read an entry from the pointer map.
+**
+** This routine retrieves the pointer map entry for page 'key', writing
+** the type and parent page number to *pEType and *pPgno respectively.
+** An error code is returned if something goes wrong, otherwise SQLITE_OK.
+*/
+static int ptrmapGet(BtShared *pBt, Pgno key, u8 *pEType, Pgno *pPgno){
+  DbPage *pDbPage;   /* The pointer map page */
+  int iPtrmap;       /* Pointer map page index */
+  u8 *pPtrmap;       /* Pointer map page data */
+  int offset;        /* Offset of entry in pointer map */
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+
+  iPtrmap = PTRMAP_PAGENO(pBt, key);
+  rc = sqlite3PagerGet(pBt->pPager, iPtrmap, &pDbPage, 0);
+  if( rc!=0 ){
+    return rc;
+  }
+  pPtrmap = (u8 *)sqlite3PagerGetData(pDbPage);
+
+  offset = PTRMAP_PTROFFSET(iPtrmap, key);
+  if( offset<0 ){
+    sqlite3PagerUnref(pDbPage);
+    return SQLITE_CORRUPT_BKPT;
+  }
+  assert( offset <= (int)pBt->usableSize-5 );
+  assert( pEType!=0 );
+  *pEType = pPtrmap[offset];
+  if( pPgno ) *pPgno = get4byte(&pPtrmap[offset+1]);
+
+  sqlite3PagerUnref(pDbPage);
+  if( *pEType<1 || *pEType>5 ) return SQLITE_CORRUPT_PGNO(iPtrmap);
+  return SQLITE_OK;
+}
+
+#else /* if defined SQLITE_OMIT_AUTOVACUUM */
+  #define ptrmapPut(w,x,y,z,rc)
+  #define ptrmapGet(w,x,y,z) SQLITE_OK
+  #define ptrmapPutOvflPtr(x, y, z, rc)
+#endif
+
+/*
+** Given a btree page and a cell index (0 means the first cell on
+** the page, 1 means the second cell, and so forth) return a pointer
+** to the cell content.
+**
+** findCellPastPtr() does the same except it skips past the initial
+** 4-byte child pointer found on interior pages, if there is one.
+**
+** This routine works only for pages that do not contain overflow cells.
+*/
+#define findCell(P,I) \
+  ((P)->aData + ((P)->maskPage & get2byteAligned(&(P)->aCellIdx[2*(I)])))
+#define findCellPastPtr(P,I) \
+  ((P)->aDataOfst + ((P)->maskPage & get2byteAligned(&(P)->aCellIdx[2*(I)])))
+
+
+/*
+** This is common tail processing for btreeParseCellPtr() and
+** btreeParseCellPtrIndex() for the case when the cell does not fit entirely
+** on a single B-tree page.  Make necessary adjustments to the CellInfo
+** structure.
+*/
+static SQLITE_NOINLINE void btreeParseCellAdjustSizeForOverflow(
+  MemPage *pPage,         /* Page containing the cell */
+  u8 *pCell,              /* Pointer to the cell text. */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  /* If the payload will not fit completely on the local page, we have
+  ** to decide how much to store locally and how much to spill onto
+  ** overflow pages.  The strategy is to minimize the amount of unused
+  ** space on overflow pages while keeping the amount of local storage
+  ** in between minLocal and maxLocal.
+  **
+  ** Warning:  changing the way overflow payload is distributed in any
+  ** way will result in an incompatible file format.
+  */
+  int minLocal;  /* Minimum amount of payload held locally */
+  int maxLocal;  /* Maximum amount of payload held locally */
+  int surplus;   /* Overflow payload available for local storage */
+
+  minLocal = pPage->minLocal;
+  maxLocal = pPage->maxLocal;
+  surplus = minLocal + (pInfo->nPayload - minLocal)%(pPage->pBt->usableSize-4);
+  testcase( surplus==maxLocal );
+  testcase( surplus==maxLocal+1 );
+  if( surplus <= maxLocal ){
+    pInfo->nLocal = (u16)surplus;
+  }else{
+    pInfo->nLocal = (u16)minLocal;
+  }
+  pInfo->nSize = (u16)(&pInfo->pPayload[pInfo->nLocal] - pCell) + 4;
+}
+
+/*
+** Given a record with nPayload bytes of payload stored within btree
+** page pPage, return the number of bytes of payload stored locally.
+*/
+static int btreePayloadToLocal(MemPage *pPage, i64 nPayload){
+  int maxLocal;  /* Maximum amount of payload held locally */
+  maxLocal = pPage->maxLocal;
+  if( nPayload<=maxLocal ){
+    return nPayload;
+  }else{
+    int minLocal;  /* Minimum amount of payload held locally */
+    int surplus;   /* Overflow payload available for local storage */
+    minLocal = pPage->minLocal;
+    surplus = minLocal + (nPayload - minLocal)%(pPage->pBt->usableSize-4);
+    return ( surplus <= maxLocal ) ? surplus : minLocal;
+  }
+}
+
+/*
+** The following routines are implementations of the MemPage.xParseCell()
+** method.
+**
+** Parse a cell content block and fill in the CellInfo structure.
+**
+** btreeParseCellPtr()        =>   table btree leaf nodes
+** btreeParseCellNoPayload()  =>   table btree internal nodes
+** btreeParseCellPtrIndex()   =>   index btree nodes
+**
+** There is also a wrapper function btreeParseCell() that works for
+** all MemPage types and that references the cell by index rather than
+** by pointer.
+*/
+static void btreeParseCellPtrNoPayload(
+  MemPage *pPage,         /* Page containing the cell */
+  u8 *pCell,              /* Pointer to the cell text. */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->leaf==0 );
+  assert( pPage->childPtrSize==4 );
+#ifndef SQLITE_DEBUG
+  UNUSED_PARAMETER(pPage);
+#endif
+  pInfo->nSize = 4 + getVarint(&pCell[4], (u64*)&pInfo->nKey);
+  pInfo->nPayload = 0;
+  pInfo->nLocal = 0;
+  pInfo->pPayload = 0;
+  return;
+}
+static void btreeParseCellPtr(
+  MemPage *pPage,         /* Page containing the cell */
+  u8 *pCell,              /* Pointer to the cell text. */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  u8 *pIter;              /* For scanning through pCell */
+  u32 nPayload;           /* Number of bytes of cell payload */
+  u64 iKey;               /* Extracted Key value */
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->leaf==0 || pPage->leaf==1 );
+  assert( pPage->intKeyLeaf );
+  assert( pPage->childPtrSize==0 );
+  pIter = pCell;
+
+  /* The next block of code is equivalent to:
+  **
+  **     pIter += getVarint32(pIter, nPayload);
+  **
+  ** The code is inlined to avoid a function call.
+  */
+  nPayload = *pIter;
+  if( nPayload>=0x80 ){
+    u8 *pEnd = &pIter[8];
+    nPayload &= 0x7f;
+    do{
+      nPayload = (nPayload<<7) | (*++pIter & 0x7f);
+    }while( (*pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+
+  /* The next block of code is equivalent to:
+  **
+  **     pIter += getVarint(pIter, (u64*)&pInfo->nKey);
+  **
+  ** The code is inlined and the loop is unrolled for performance.
+  ** This routine is a high-runner.
+  */
+  iKey = *pIter;
+  if( iKey>=0x80 ){
+    u8 x;
+    iKey = (iKey<<7) ^ (x = *++pIter);
+    if( x>=0x80 ){
+      iKey = (iKey<<7) ^ (x = *++pIter);
+      if( x>=0x80 ){
+        iKey = (iKey<<7) ^ 0x10204000 ^ (x = *++pIter);
+        if( x>=0x80 ){
+          iKey = (iKey<<7) ^ 0x4000 ^ (x = *++pIter);
+          if( x>=0x80 ){
+            iKey = (iKey<<7) ^ 0x4000 ^ (x = *++pIter);
+            if( x>=0x80 ){
+              iKey = (iKey<<7) ^ 0x4000 ^ (x = *++pIter);
+              if( x>=0x80 ){
+                iKey = (iKey<<7) ^ 0x4000 ^ (x = *++pIter);
+                if( x>=0x80 ){
+                  iKey = (iKey<<8) ^ 0x8000 ^ (*++pIter);
+                }
+              }
+            }
+          }
+        }
+      }else{
+        iKey ^= 0x204000;
+      }
+    }else{
+      iKey ^= 0x4000;
+    }
+  }
+  pIter++;
+
+  pInfo->nKey = *(i64*)&iKey;
+  pInfo->nPayload = nPayload;
+  pInfo->pPayload = pIter;
+  testcase( nPayload==pPage->maxLocal );
+  testcase( nPayload==(u32)pPage->maxLocal+1 );
+  if( nPayload<=pPage->maxLocal ){
+    /* This is the (easy) common case where the entire payload fits
+    ** on the local page.  No overflow is required.
+    */
+    pInfo->nSize = nPayload + (u16)(pIter - pCell);
+    if( pInfo->nSize<4 ) pInfo->nSize = 4;
+    pInfo->nLocal = (u16)nPayload;
+  }else{
+    btreeParseCellAdjustSizeForOverflow(pPage, pCell, pInfo);
+  }
+}
+static void btreeParseCellPtrIndex(
+  MemPage *pPage,         /* Page containing the cell */
+  u8 *pCell,              /* Pointer to the cell text. */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  u8 *pIter;              /* For scanning through pCell */
+  u32 nPayload;           /* Number of bytes of cell payload */
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->leaf==0 || pPage->leaf==1 );
+  assert( pPage->intKeyLeaf==0 );
+  pIter = pCell + pPage->childPtrSize;
+  nPayload = *pIter;
+  if( nPayload>=0x80 ){
+    u8 *pEnd = &pIter[8];
+    nPayload &= 0x7f;
+    do{
+      nPayload = (nPayload<<7) | (*++pIter & 0x7f);
+    }while( *(pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+  pInfo->nKey = nPayload;
+  pInfo->nPayload = nPayload;
+  pInfo->pPayload = pIter;
+  testcase( nPayload==pPage->maxLocal );
+  testcase( nPayload==(u32)pPage->maxLocal+1 );
+  if( nPayload<=pPage->maxLocal ){
+    /* This is the (easy) common case where the entire payload fits
+    ** on the local page.  No overflow is required.
+    */
+    pInfo->nSize = nPayload + (u16)(pIter - pCell);
+    if( pInfo->nSize<4 ) pInfo->nSize = 4;
+    pInfo->nLocal = (u16)nPayload;
+  }else{
+    btreeParseCellAdjustSizeForOverflow(pPage, pCell, pInfo);
+  }
+}
+static void btreeParseCell(
+  MemPage *pPage,         /* Page containing the cell */
+  int iCell,              /* The cell index.  First cell is 0 */
+  CellInfo *pInfo         /* Fill in this structure */
+){
+  pPage->xParseCell(pPage, findCell(pPage, iCell), pInfo);
+}
+
+/*
+** The following routines are implementations of the MemPage.xCellSize
+** method.
+**
+** Compute the total number of bytes that a Cell needs in the cell
+** data area of the btree-page.  The return number includes the cell
+** data header and the local payload, but not any overflow page or
+** the space used by the cell pointer.
+**
+** cellSizePtrNoPayload()    =>   table internal nodes
+** cellSizePtrTableLeaf()    =>   table leaf nodes
+** cellSizePtr()             =>   index internal nodes
+** cellSizeIdxLeaf()         =>   index leaf nodes
+*/
+static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell + 4;                   /* For looping over bytes of pCell */
+  u8 *pEnd;                                /* End mark for a varint */
+  u32 nSize;                               /* Size value to return */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  pPage->xParseCell(pPage, pCell, &debuginfo);
+#endif
+
+  assert( pPage->childPtrSize==4 );
+  nSize = *pIter;
+  if( nSize>=0x80 ){
+    pEnd = &pIter[8];
+    nSize &= 0x7f;
+    do{
+      nSize = (nSize<<7) | (*++pIter & 0x7f);
+    }while( *(pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+  testcase( nSize==pPage->maxLocal );
+  testcase( nSize==(u32)pPage->maxLocal+1 );
+  if( nSize<=pPage->maxLocal ){
+    nSize += (u32)(pIter - pCell);
+    assert( nSize>4 );
+  }else{
+    int minLocal = pPage->minLocal;
+    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
+    testcase( nSize==pPage->maxLocal );
+    testcase( nSize==(u32)pPage->maxLocal+1 );
+    if( nSize>pPage->maxLocal ){
+      nSize = minLocal;
+    }
+    nSize += 4 + (u16)(pIter - pCell);
+  }
+  assert( nSize==debuginfo.nSize || CORRUPT_DB );
+  return (u16)nSize;
+}
+static u16 cellSizePtrIdxLeaf(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell;                       /* For looping over bytes of pCell */
+  u8 *pEnd;                                /* End mark for a varint */
+  u32 nSize;                               /* Size value to return */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  pPage->xParseCell(pPage, pCell, &debuginfo);
+#endif
+
+  assert( pPage->childPtrSize==0 );
+  nSize = *pIter;
+  if( nSize>=0x80 ){
+    pEnd = &pIter[8];
+    nSize &= 0x7f;
+    do{
+      nSize = (nSize<<7) | (*++pIter & 0x7f);
+    }while( *(pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+  testcase( nSize==pPage->maxLocal );
+  testcase( nSize==(u32)pPage->maxLocal+1 );
+  if( nSize<=pPage->maxLocal ){
+    nSize += (u32)(pIter - pCell);
+    if( nSize<4 ) nSize = 4;
+  }else{
+    int minLocal = pPage->minLocal;
+    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
+    testcase( nSize==pPage->maxLocal );
+    testcase( nSize==(u32)pPage->maxLocal+1 );
+    if( nSize>pPage->maxLocal ){
+      nSize = minLocal;
+    }
+    nSize += 4 + (u16)(pIter - pCell);
+  }
+  assert( nSize==debuginfo.nSize || CORRUPT_DB );
+  return (u16)nSize;
+}
+static u16 cellSizePtrNoPayload(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell + 4; /* For looping over bytes of pCell */
+  u8 *pEnd;              /* End mark for a varint */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  pPage->xParseCell(pPage, pCell, &debuginfo);
+#else
+  UNUSED_PARAMETER(pPage);
+#endif
+
+  assert( pPage->childPtrSize==4 );
+  pEnd = pIter + 9;
+  while( (*pIter++)&0x80 && pIter<pEnd );
+  assert( debuginfo.nSize==(u16)(pIter - pCell) || CORRUPT_DB );
+  return (u16)(pIter - pCell);
+}
+static u16 cellSizePtrTableLeaf(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell;   /* For looping over bytes of pCell */
+  u8 *pEnd;            /* End mark for a varint */
+  u32 nSize;           /* Size value to return */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  pPage->xParseCell(pPage, pCell, &debuginfo);
+#endif
+
+  nSize = *pIter;
+  if( nSize>=0x80 ){
+    pEnd = &pIter[8];
+    nSize &= 0x7f;
+    do{
+      nSize = (nSize<<7) | (*++pIter & 0x7f);
+    }while( *(pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+  /* pIter now points at the 64-bit integer key value, a variable length
+  ** integer. The following block moves pIter to point at the first byte
+  ** past the end of the key value. */
+  if( (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80
+   && (*pIter++)&0x80 ){ pIter++; }
+  testcase( nSize==pPage->maxLocal );
+  testcase( nSize==(u32)pPage->maxLocal+1 );
+  if( nSize<=pPage->maxLocal ){
+    nSize += (u32)(pIter - pCell);
+    if( nSize<4 ) nSize = 4;
+  }else{
+    int minLocal = pPage->minLocal;
+    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
+    testcase( nSize==pPage->maxLocal );
+    testcase( nSize==(u32)pPage->maxLocal+1 );
+    if( nSize>pPage->maxLocal ){
+      nSize = minLocal;
+    }
+    nSize += 4 + (u16)(pIter - pCell);
+  }
+  assert( nSize==debuginfo.nSize || CORRUPT_DB );
+  return (u16)nSize;
+}
+
+
+#ifdef SQLITE_DEBUG
+/* This variation on cellSizePtr() is used inside of assert() statements
+** only. */
+static u16 cellSize(MemPage *pPage, int iCell){
+  return pPage->xCellSize(pPage, findCell(pPage, iCell));
+}
+#endif
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** The cell pCell is currently part of page pSrc but will ultimately be part
+** of pPage.  (pSrc and pPage are often the same.)  If pCell contains a
+** pointer to an overflow page, insert an entry into the pointer-map for
+** the overflow page that will be valid after pCell has been moved to pPage.
+*/
+static void ptrmapPutOvflPtr(MemPage *pPage, MemPage *pSrc, u8 *pCell,int *pRC){
+  CellInfo info;
+  if( *pRC ) return;
+  assert( pCell!=0 );
+  pPage->xParseCell(pPage, pCell, &info);
+  if( info.nLocal<info.nPayload ){
+    Pgno ovfl;
+    if( SQLITE_OVERFLOW(pSrc->aDataEnd, pCell, pCell+info.nLocal) ){
+      testcase( pSrc!=pPage );
+      *pRC = SQLITE_CORRUPT_BKPT;
+      return;
+    }
+    ovfl = get4byte(&pCell[info.nSize-4]);
+    ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
+  }
+}
+#endif
+
+
+/*
+** Defragment the page given. This routine reorganizes cells within the
+** page so that there are no free-blocks on the free-block list.
+**
+** Parameter nMaxFrag is the maximum amount of fragmented space that may be
+** present in the page after this routine returns.
+**
+** EVIDENCE-OF: R-44582-60138 SQLite may from time to time reorganize a
+** b-tree page so that there are no freeblocks or fragment bytes, all
+** unused bytes are contained in the unallocated space region, and all
+** cells are packed tightly at the end of the page.
+*/
+static int defragmentPage(MemPage *pPage, int nMaxFrag){
+  int i;                     /* Loop counter */
+  int pc;                    /* Address of the i-th cell */
+  int hdr;                   /* Offset to the page header */
+  int size;                  /* Size of a cell */
+  int usableSize;            /* Number of usable bytes on a page */
+  int cellOffset;            /* Offset to the cell pointer array */
+  int cbrk;                  /* Offset to the cell content area */
+  int nCell;                 /* Number of cells on the page */
+  unsigned char *data;       /* The page data */
+  unsigned char *temp;       /* Temp area for cell content */
+  unsigned char *src;        /* Source of content */
+  int iCellFirst;            /* First allowable cell index */
+  int iCellLast;             /* Last possible cell index */
+  int iCellStart;            /* First cell offset in input */
+
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( pPage->pBt!=0 );
+  assert( pPage->pBt->usableSize <= SQLITE_MAX_PAGE_SIZE );
+  assert( pPage->nOverflow==0 );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  data = pPage->aData;
+  hdr = pPage->hdrOffset;
+  cellOffset = pPage->cellOffset;
+  nCell = pPage->nCell;
+  assert( nCell==get2byte(&data[hdr+3]) || CORRUPT_DB );
+  iCellFirst = cellOffset + 2*nCell;
+  usableSize = pPage->pBt->usableSize;
+
+  /* This block handles pages with two or fewer free blocks and nMaxFrag
+  ** or fewer fragmented bytes. In this case it is faster to move the
+  ** two (or one) blocks of cells using memmove() and add the required
+  ** offsets to each pointer in the cell-pointer array than it is to
+  ** reconstruct the entire page.  */
+  if( (int)data[hdr+7]<=nMaxFrag ){
+    int iFree = get2byte(&data[hdr+1]);
+    if( iFree>usableSize-4 ) return SQLITE_CORRUPT_PAGE(pPage);
+    if( iFree ){
+      int iFree2 = get2byte(&data[iFree]);
+      if( iFree2>usableSize-4 ) return SQLITE_CORRUPT_PAGE(pPage);
+      if( 0==iFree2 || (data[iFree2]==0 && data[iFree2+1]==0) ){
+        u8 *pEnd = &data[cellOffset + nCell*2];
+        u8 *pAddr;
+        int sz2 = 0;
+        int sz = get2byte(&data[iFree+2]);
+        int top = get2byte(&data[hdr+5]);
+        if( top>=iFree ){
+          return SQLITE_CORRUPT_PAGE(pPage);
+        }
+        if( iFree2 ){
+          if( iFree+sz>iFree2 ) return SQLITE_CORRUPT_PAGE(pPage);
+          sz2 = get2byte(&data[iFree2+2]);
+          if( iFree2+sz2 > usableSize ) return SQLITE_CORRUPT_PAGE(pPage);
+          memmove(&data[iFree+sz+sz2], &data[iFree+sz], iFree2-(iFree+sz));
+          sz += sz2;
+        }else if( iFree+sz>usableSize ){
+          return SQLITE_CORRUPT_PAGE(pPage);
+        }
+
+        cbrk = top+sz;
+        assert( cbrk+(iFree-top) <= usableSize );
+        memmove(&data[cbrk], &data[top], iFree-top);
+        for(pAddr=&data[cellOffset]; pAddr<pEnd; pAddr+=2){
+          pc = get2byte(pAddr);
+          if( pc<iFree ){ put2byte(pAddr, pc+sz); }
+          else if( pc<iFree2 ){ put2byte(pAddr, pc+sz2); }
+        }
+        goto defragment_out;
+      }
+    }
+  }
+
+  cbrk = usableSize;
+  iCellLast = usableSize - 4;
+  iCellStart = get2byte(&data[hdr+5]);
+  if( nCell>0 ){
+    temp = sqlite3PagerTempSpace(pPage->pBt->pPager);
+    memcpy(temp, data, usableSize);
+    src = temp;
+    for(i=0; i<nCell; i++){
+      u8 *pAddr;     /* The i-th cell pointer */
+      pAddr = &data[cellOffset + i*2];
+      pc = get2byte(pAddr);
+      testcase( pc==iCellFirst );
+      testcase( pc==iCellLast );
+      /* These conditions have already been verified in btreeInitPage()
+      ** if PRAGMA cell_size_check=ON.
+      */
+      if( pc>iCellLast ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      assert( pc>=0 && pc<=iCellLast );
+      size = pPage->xCellSize(pPage, &src[pc]);
+      cbrk -= size;
+      if( cbrk<iCellStart || pc+size>usableSize ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      assert( cbrk+size<=usableSize && cbrk>=iCellStart );
+      testcase( cbrk+size==usableSize );
+      testcase( pc+size==usableSize );
+      put2byte(pAddr, cbrk);
+      memcpy(&data[cbrk], &src[pc], size);
+    }
+  }
+  data[hdr+7] = 0;
+
+defragment_out:
+  assert( pPage->nFree>=0 );
+  if( data[hdr+7]+cbrk-iCellFirst!=pPage->nFree ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  assert( cbrk>=iCellFirst );
+  put2byte(&data[hdr+5], cbrk);
+  data[hdr+1] = 0;
+  data[hdr+2] = 0;
+  memset(&data[iCellFirst], 0, cbrk-iCellFirst);
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  return SQLITE_OK;
+}
+
+/*
+** Search the free-list on page pPg for space to store a cell nByte bytes in
+** size. If one can be found, return a pointer to the space and remove it
+** from the free-list.
+**
+** If no suitable space can be found on the free-list, return NULL.
+**
+** This function may detect corruption within pPg.  If corruption is
+** detected then *pRc is set to SQLITE_CORRUPT and NULL is returned.
+**
+** Slots on the free list that are between 1 and 3 bytes larger than nByte
+** will be ignored if adding the extra space to the fragmentation count
+** causes the fragmentation count to exceed 60.
+*/
+static u8 *pageFindSlot(MemPage *pPg, int nByte, int *pRc){
+  const int hdr = pPg->hdrOffset;            /* Offset to page header */
+  u8 * const aData = pPg->aData;             /* Page data */
+  int iAddr = hdr + 1;                       /* Address of ptr to pc */
+  u8 *pTmp = &aData[iAddr];                  /* Temporary ptr into aData[] */
+  int pc = get2byte(pTmp);                   /* Address of a free slot */
+  int x;                                     /* Excess size of the slot */
+  int maxPC = pPg->pBt->usableSize - nByte;  /* Max address for a usable slot */
+  int size;                                  /* Size of the free slot */
+
+  assert( pc>0 );
+  while( pc<=maxPC ){
+    /* EVIDENCE-OF: R-22710-53328 The third and fourth bytes of each
+    ** freeblock form a big-endian integer which is the size of the freeblock
+    ** in bytes, including the 4-byte header. */
+    pTmp = &aData[pc+2];
+    size = get2byte(pTmp);
+    if( (x = size - nByte)>=0 ){
+      testcase( x==4 );
+      testcase( x==3 );
+      if( x<4 ){
+        /* EVIDENCE-OF: R-11498-58022 In a well-formed b-tree page, the total
+        ** number of bytes in fragments may not exceed 60. */
+        if( aData[hdr+7]>57 ) return 0;
+
+        /* Remove the slot from the free-list. Update the number of
+        ** fragmented bytes within the page. */
+        memcpy(&aData[iAddr], &aData[pc], 2);
+        aData[hdr+7] += (u8)x;
+        return &aData[pc];
+      }else if( x+pc > maxPC ){
+        /* This slot extends off the end of the usable part of the page */
+        *pRc = SQLITE_CORRUPT_PAGE(pPg);
+        return 0;
+      }else{
+        /* The slot remains on the free-list. Reduce its size to account
+        ** for the portion used by the new allocation. */
+        put2byte(&aData[pc+2], x);
+      }
+      return &aData[pc + x];
+    }
+    iAddr = pc;
+    pTmp = &aData[pc];
+    pc = get2byte(pTmp);
+    if( pc<=iAddr ){
+      if( pc ){
+        /* The next slot in the chain comes before the current slot */
+        *pRc = SQLITE_CORRUPT_PAGE(pPg);
+      }
+      return 0;
+    }
+  }
+  if( pc>maxPC+nByte-4 ){
+    /* The free slot chain extends off the end of the page */
+    *pRc = SQLITE_CORRUPT_PAGE(pPg);
+  }
+  return 0;
+}
+
+/*
+** Allocate nByte bytes of space from within the B-Tree page passed
+** as the first argument. Write into *pIdx the index into pPage->aData[]
+** of the first byte of allocated space. Return either SQLITE_OK or
+** an error code (usually SQLITE_CORRUPT).
+**
+** The caller guarantees that there is sufficient space to make the
+** allocation.  This routine might need to defragment in order to bring
+** all the space together, however.  This routine will avoid using
+** the first two bytes past the cell pointer area since presumably this
+** allocation is being made in order to insert a new cell, so we will
+** also end up needing a new cell pointer.
+*/
+static SQLITE_INLINE int allocateSpace(MemPage *pPage, int nByte, int *pIdx){
+  const int hdr = pPage->hdrOffset;    /* Local cache of pPage->hdrOffset */
+  u8 * const data = pPage->aData;      /* Local cache of pPage->aData */
+  int top;                             /* First byte of cell content area */
+  int rc = SQLITE_OK;                  /* Integer return code */
+  u8 *pTmp;                            /* Temp ptr into data[] */
+  int gap;        /* First byte of gap between cell pointers and cell content */
+
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( pPage->pBt );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( nByte>=0 );  /* Minimum cell size is 4 */
+  assert( pPage->nFree>=nByte );
+  assert( pPage->nOverflow==0 );
+  assert( nByte < (int)(pPage->pBt->usableSize-8) );
+
+  assert( pPage->cellOffset == hdr + 12 - 4*pPage->leaf );
+  gap = pPage->cellOffset + 2*pPage->nCell;
+  assert( gap<=65536 );
+  /* EVIDENCE-OF: R-29356-02391 If the database uses a 65536-byte page size
+  ** and the reserved space is zero (the usual value for reserved space)
+  ** then the cell content offset of an empty page wants to be 65536.
+  ** However, that integer is too large to be stored in a 2-byte unsigned
+  ** integer, so a value of 0 is used in its place. */
+  pTmp = &data[hdr+5];
+  top = get2byte(pTmp);
+  if( gap>top ){
+    if( top==0 && pPage->pBt->usableSize==65536 ){
+      top = 65536;
+    }else{
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }else if( top>(int)pPage->pBt->usableSize ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+
+  /* If there is enough space between gap and top for one more cell pointer,
+  ** and if the freelist is not empty, then search the
+  ** freelist looking for a slot big enough to satisfy the request.
+  */
+  testcase( gap+2==top );
+  testcase( gap+1==top );
+  testcase( gap==top );
+  if( (data[hdr+2] || data[hdr+1]) && gap+2<=top ){
+    u8 *pSpace = pageFindSlot(pPage, nByte, &rc);
+    if( pSpace ){
+      int g2;
+      assert( pSpace+nByte<=data+pPage->pBt->usableSize );
+      *pIdx = g2 = (int)(pSpace-data);
+      if( g2<=gap ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }else{
+        return SQLITE_OK;
+      }
+    }else if( rc ){
+      return rc;
+    }
+  }
+
+  /* The request could not be fulfilled using a freelist slot.  Check
+  ** to see if defragmentation is necessary.
+  */
+  testcase( gap+2+nByte==top );
+  if( gap+2+nByte>top ){
+    assert( pPage->nCell>0 || CORRUPT_DB );
+    assert( pPage->nFree>=0 );
+    rc = defragmentPage(pPage, MIN(4, pPage->nFree - (2+nByte)));
+    if( rc ) return rc;
+    top = get2byteNotZero(&data[hdr+5]);
+    assert( gap+2+nByte<=top );
+  }
+
+
+  /* Allocate memory from the gap in between the cell pointer array
+  ** and the cell content area.  The btreeComputeFreeSpace() call has already
+  ** validated the freelist.  Given that the freelist is valid, there
+  ** is no way that the allocation can extend off the end of the page.
+  ** The assert() below verifies the previous sentence.
+  */
+  top -= nByte;
+  put2byte(&data[hdr+5], top);
+  assert( top+nByte <= (int)pPage->pBt->usableSize );
+  *pIdx = top;
+  return SQLITE_OK;
+}
+
+/*
+** Return a section of the pPage->aData to the freelist.
+** The first byte of the new free block is pPage->aData[iStart]
+** and the size of the block is iSize bytes.
+**
+** Adjacent freeblocks are coalesced.
+**
+** Even though the freeblock list was checked by btreeComputeFreeSpace(),
+** that routine will not detect overlap between cells or freeblocks.  Nor
+** does it detect cells or freeblocks that encroach into the reserved bytes
+** at the end of the page.  So do additional corruption checks inside this
+** routine and return SQLITE_CORRUPT if any problems are found.
+*/
+static int freeSpace(MemPage *pPage, u16 iStart, u16 iSize){
+  u16 iPtr;                             /* Address of ptr to next freeblock */
+  u16 iFreeBlk;                         /* Address of the next freeblock */
+  u8 hdr;                               /* Page header size.  0 or 100 */
+  u8 nFrag = 0;                         /* Reduction in fragmentation */
+  u16 iOrigSize = iSize;                /* Original value of iSize */
+  u16 x;                                /* Offset to cell content area */
+  u32 iEnd = iStart + iSize;            /* First byte past the iStart buffer */
+  unsigned char *data = pPage->aData;   /* Page content */
+  u8 *pTmp;                             /* Temporary ptr into data[] */
+
+  assert( pPage->pBt!=0 );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( CORRUPT_DB || iStart>=pPage->hdrOffset+6+pPage->childPtrSize );
+  assert( CORRUPT_DB || iEnd <= pPage->pBt->usableSize );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( iSize>=4 );   /* Minimum cell size is 4 */
+  assert( CORRUPT_DB || iStart<=pPage->pBt->usableSize-4 );
+
+  /* The list of freeblocks must be in ascending order.  Find the
+  ** spot on the list where iStart should be inserted.
+  */
+  hdr = pPage->hdrOffset;
+  iPtr = hdr + 1;
+  if( data[iPtr+1]==0 && data[iPtr]==0 ){
+    iFreeBlk = 0;  /* Shortcut for the case when the freelist is empty */
+  }else{
+    while( (iFreeBlk = get2byte(&data[iPtr]))<iStart ){
+      if( iFreeBlk<=iPtr ){
+        if( iFreeBlk==0 ) break; /* TH3: corrupt082.100 */
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      iPtr = iFreeBlk;
+    }
+    if( iFreeBlk>pPage->pBt->usableSize-4 ){ /* TH3: corrupt081.100 */
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    assert( iFreeBlk>iPtr || iFreeBlk==0 || CORRUPT_DB );
+
+    /* At this point:
+    **    iFreeBlk:   First freeblock after iStart, or zero if none
+    **    iPtr:       The address of a pointer to iFreeBlk
+    **
+    ** Check to see if iFreeBlk should be coalesced onto the end of iStart.
+    */
+    if( iFreeBlk && iEnd+3>=iFreeBlk ){
+      nFrag = iFreeBlk - iEnd;
+      if( iEnd>iFreeBlk ) return SQLITE_CORRUPT_PAGE(pPage);
+      iEnd = iFreeBlk + get2byte(&data[iFreeBlk+2]);
+      if( iEnd > pPage->pBt->usableSize ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      iSize = iEnd - iStart;
+      iFreeBlk = get2byte(&data[iFreeBlk]);
+    }
+
+    /* If iPtr is another freeblock (that is, if iPtr is not the freelist
+    ** pointer in the page header) then check to see if iStart should be
+    ** coalesced onto the end of iPtr.
+    */
+    if( iPtr>hdr+1 ){
+      int iPtrEnd = iPtr + get2byte(&data[iPtr+2]);
+      if( iPtrEnd+3>=iStart ){
+        if( iPtrEnd>iStart ) return SQLITE_CORRUPT_PAGE(pPage);
+        nFrag += iStart - iPtrEnd;
+        iSize = iEnd - iPtr;
+        iStart = iPtr;
+      }
+    }
+    if( nFrag>data[hdr+7] ) return SQLITE_CORRUPT_PAGE(pPage);
+    data[hdr+7] -= nFrag;
+  }
+  pTmp = &data[hdr+5];
+  x = get2byte(pTmp);
+  if( pPage->pBt->btsFlags & BTS_FAST_SECURE ){
+    /* Overwrite deleted information with zeros when the secure_delete
+    ** option is enabled */
+    memset(&data[iStart], 0, iSize);
+  }
+  if( iStart<=x ){
+    /* The new freeblock is at the beginning of the cell content area,
+    ** so just extend the cell content area rather than create another
+    ** freelist entry */
+    if( iStart<x ) return SQLITE_CORRUPT_PAGE(pPage);
+    if( iPtr!=hdr+1 ) return SQLITE_CORRUPT_PAGE(pPage);
+    put2byte(&data[hdr+1], iFreeBlk);
+    put2byte(&data[hdr+5], iEnd);
+  }else{
+    /* Insert the new freeblock into the freelist */
+    put2byte(&data[iPtr], iStart);
+    put2byte(&data[iStart], iFreeBlk);
+    put2byte(&data[iStart+2], iSize);
+  }
+  pPage->nFree += iOrigSize;
+  return SQLITE_OK;
+}
+
+/*
+** Decode the flags byte (the first byte of the header) for a page
+** and initialize fields of the MemPage structure accordingly.
+**
+** Only the following combinations are supported.  Anything different
+** indicates a corrupt database files:
+**
+**         PTF_ZERODATA                             (0x02,  2)
+**         PTF_LEAFDATA | PTF_INTKEY                (0x05,  5)
+**         PTF_ZERODATA | PTF_LEAF                  (0x0a, 10)
+**         PTF_LEAFDATA | PTF_INTKEY | PTF_LEAF     (0x0d, 13)
+*/
+static int decodeFlags(MemPage *pPage, int flagByte){
+  BtShared *pBt;     /* A copy of pPage->pBt */
+
+  assert( pPage->hdrOffset==(pPage->pgno==1 ? 100 : 0) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  pBt = pPage->pBt;
+  pPage->max1bytePayload = pBt->max1bytePayload;
+  if( flagByte>=(PTF_ZERODATA | PTF_LEAF) ){
+    pPage->childPtrSize = 0;
+    pPage->leaf = 1;
+    if( flagByte==(PTF_LEAFDATA | PTF_INTKEY | PTF_LEAF) ){
+      pPage->intKeyLeaf = 1;
+      pPage->xCellSize = cellSizePtrTableLeaf;
+      pPage->xParseCell = btreeParseCellPtr;
+      pPage->intKey = 1;
+      pPage->maxLocal = pBt->maxLeaf;
+      pPage->minLocal = pBt->minLeaf;
+    }else if( flagByte==(PTF_ZERODATA | PTF_LEAF) ){
+      pPage->intKey = 0;
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtrIdxLeaf;
+      pPage->xParseCell = btreeParseCellPtrIndex;
+      pPage->maxLocal = pBt->maxLocal;
+      pPage->minLocal = pBt->minLocal;
+    }else{
+      pPage->intKey = 0;
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtrIdxLeaf;
+      pPage->xParseCell = btreeParseCellPtrIndex;
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }else{
+    pPage->childPtrSize = 4;
+    pPage->leaf = 0;
+    if( flagByte==(PTF_ZERODATA) ){
+      pPage->intKey = 0;
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtr;
+      pPage->xParseCell = btreeParseCellPtrIndex;
+      pPage->maxLocal = pBt->maxLocal;
+      pPage->minLocal = pBt->minLocal;
+    }else if( flagByte==(PTF_LEAFDATA | PTF_INTKEY) ){
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtrNoPayload;
+      pPage->xParseCell = btreeParseCellPtrNoPayload;
+      pPage->intKey = 1;
+      pPage->maxLocal = pBt->maxLeaf;
+      pPage->minLocal = pBt->minLeaf;
+    }else{
+      pPage->intKey = 0;
+      pPage->intKeyLeaf = 0;
+      pPage->xCellSize = cellSizePtr;
+      pPage->xParseCell = btreeParseCellPtrIndex;
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Compute the amount of freespace on the page.  In other words, fill
+** in the pPage->nFree field.
+*/
+static int btreeComputeFreeSpace(MemPage *pPage){
+  int pc;            /* Address of a freeblock within pPage->aData[] */
+  u8 hdr;            /* Offset to beginning of page header */
+  u8 *data;          /* Equal to pPage->aData */
+  int usableSize;    /* Amount of usable space on each page */
+  int nFree;         /* Number of unused bytes on the page */
+  int top;           /* First byte of the cell content area */
+  int iCellFirst;    /* First allowable cell or freeblock offset */
+  int iCellLast;     /* Last possible cell or freeblock offset */
+
+  assert( pPage->pBt!=0 );
+  assert( pPage->pBt->db!=0 );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->pgno==sqlite3PagerPagenumber(pPage->pDbPage) );
+  assert( pPage == sqlite3PagerGetExtra(pPage->pDbPage) );
+  assert( pPage->aData == sqlite3PagerGetData(pPage->pDbPage) );
+  assert( pPage->isInit==1 );
+  assert( pPage->nFree<0 );
+
+  usableSize = pPage->pBt->usableSize;
+  hdr = pPage->hdrOffset;
+  data = pPage->aData;
+  /* EVIDENCE-OF: R-58015-48175 The two-byte integer at offset 5 designates
+  ** the start of the cell content area. A zero value for this integer is
+  ** interpreted as 65536. */
+  top = get2byteNotZero(&data[hdr+5]);
+  iCellFirst = hdr + 8 + pPage->childPtrSize + 2*pPage->nCell;
+  iCellLast = usableSize - 4;
+
+  /* Compute the total free space on the page
+  ** EVIDENCE-OF: R-23588-34450 The two-byte integer at offset 1 gives the
+  ** start of the first freeblock on the page, or is zero if there are no
+  ** freeblocks. */
+  pc = get2byte(&data[hdr+1]);
+  nFree = data[hdr+7] + top;  /* Init nFree to non-freeblock free space */
+  if( pc>0 ){
+    u32 next, size;
+    if( pc<top ){
+      /* EVIDENCE-OF: R-55530-52930 In a well-formed b-tree page, there will
+      ** always be at least one cell before the first freeblock.
+      */
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    while( 1 ){
+      if( pc>iCellLast ){
+        /* Freeblock off the end of the page */
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      next = get2byte(&data[pc]);
+      size = get2byte(&data[pc+2]);
+      nFree = nFree + size;
+      if( next<=pc+size+3 ) break;
+      pc = next;
+    }
+    if( next>0 ){
+      /* Freeblock not in ascending order */
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    if( pc+size>(unsigned int)usableSize ){
+      /* Last freeblock extends past page end */
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }
+
+  /* At this point, nFree contains the sum of the offset to the start
+  ** of the cell-content area plus the number of free bytes within
+  ** the cell-content area. If this is greater than the usable-size
+  ** of the page, then the page must be corrupted. This check also
+  ** serves to verify that the offset to the start of the cell-content
+  ** area, according to the page header, lies within the page.
+  */
+  if( nFree>usableSize || nFree<iCellFirst ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  pPage->nFree = (u16)(nFree - iCellFirst);
+  return SQLITE_OK;
+}
+
+/*
+** Do additional sanity check after btreeInitPage() if
+** PRAGMA cell_size_check=ON
+*/
+static SQLITE_NOINLINE int btreeCellSizeCheck(MemPage *pPage){
+  int iCellFirst;    /* First allowable cell or freeblock offset */
+  int iCellLast;     /* Last possible cell or freeblock offset */
+  int i;             /* Index into the cell pointer array */
+  int sz;            /* Size of a cell */
+  int pc;            /* Address of a freeblock within pPage->aData[] */
+  u8 *data;          /* Equal to pPage->aData */
+  int usableSize;    /* Maximum usable space on the page */
+  int cellOffset;    /* Start of cell content area */
+
+  iCellFirst = pPage->cellOffset + 2*pPage->nCell;
+  usableSize = pPage->pBt->usableSize;
+  iCellLast = usableSize - 4;
+  data = pPage->aData;
+  cellOffset = pPage->cellOffset;
+  if( !pPage->leaf ) iCellLast--;
+  for(i=0; i<pPage->nCell; i++){
+    pc = get2byteAligned(&data[cellOffset+i*2]);
+    testcase( pc==iCellFirst );
+    testcase( pc==iCellLast );
+    if( pc<iCellFirst || pc>iCellLast ){
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    sz = pPage->xCellSize(pPage, &data[pc]);
+    testcase( pc+sz==usableSize );
+    if( pc+sz>usableSize ){
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Initialize the auxiliary information for a disk block.
+**
+** Return SQLITE_OK on success.  If we see that the page does
+** not contain a well-formed database page, then return
+** SQLITE_CORRUPT.  Note that a return of SQLITE_OK does not
+** guarantee that the page is well-formed.  It only shows that
+** we failed to detect any corruption.
+*/
+static int btreeInitPage(MemPage *pPage){
+  u8 *data;          /* Equal to pPage->aData */
+  BtShared *pBt;        /* The main btree structure */
+
+  assert( pPage->pBt!=0 );
+  assert( pPage->pBt->db!=0 );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->pgno==sqlite3PagerPagenumber(pPage->pDbPage) );
+  assert( pPage == sqlite3PagerGetExtra(pPage->pDbPage) );
+  assert( pPage->aData == sqlite3PagerGetData(pPage->pDbPage) );
+  assert( pPage->isInit==0 );
+
+  pBt = pPage->pBt;
+  data = pPage->aData + pPage->hdrOffset;
+  /* EVIDENCE-OF: R-28594-02890 The one-byte flag at offset 0 indicating
+  ** the b-tree page type. */
+  if( decodeFlags(pPage, data[0]) ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
+  pPage->maskPage = (u16)(pBt->pageSize - 1);
+  pPage->nOverflow = 0;
+  pPage->cellOffset = pPage->hdrOffset + 8 + pPage->childPtrSize;
+  pPage->aCellIdx = data + pPage->childPtrSize + 8;
+  pPage->aDataEnd = pPage->aData + pBt->pageSize;
+  pPage->aDataOfst = pPage->aData + pPage->childPtrSize;
+  /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the
+  ** number of cells on the page. */
+  pPage->nCell = get2byte(&data[3]);
+  if( pPage->nCell>MX_CELL(pBt) ){
+    /* To many cells for a single page.  The page must be corrupt */
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  testcase( pPage->nCell==MX_CELL(pBt) );
+  /* EVIDENCE-OF: R-24089-57979 If a page contains no cells (which is only
+  ** possible for a root page of a table that contains no rows) then the
+  ** offset to the cell content area will equal the page size minus the
+  ** bytes of reserved space. */
+  assert( pPage->nCell>0
+       || get2byteNotZero(&data[5])==(int)pBt->usableSize
+       || CORRUPT_DB );
+  pPage->nFree = -1;  /* Indicate that this value is yet uncomputed */
+  pPage->isInit = 1;
+  if( pBt->db->flags & SQLITE_CellSizeCk ){
+    return btreeCellSizeCheck(pPage);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Set up a raw page so that it looks like a database page holding
+** no entries.
+*/
+static void zeroPage(MemPage *pPage, int flags){
+  unsigned char *data = pPage->aData;
+  BtShared *pBt = pPage->pBt;
+  u8 hdr = pPage->hdrOffset;
+  u16 first;
+
+  assert( sqlite3PagerPagenumber(pPage->pDbPage)==pPage->pgno || CORRUPT_DB );
+  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
+  assert( sqlite3PagerGetData(pPage->pDbPage) == data );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pBt->btsFlags & BTS_FAST_SECURE ){
+    memset(&data[hdr], 0, pBt->usableSize - hdr);
+  }
+  data[hdr] = (char)flags;
+  first = hdr + ((flags&PTF_LEAF)==0 ? 12 : 8);
+  memset(&data[hdr+1], 0, 4);
+  data[hdr+7] = 0;
+  put2byte(&data[hdr+5], pBt->usableSize);
+  pPage->nFree = (u16)(pBt->usableSize - first);
+  decodeFlags(pPage, flags);
+  pPage->cellOffset = first;
+  pPage->aDataEnd = &data[pBt->pageSize];
+  pPage->aCellIdx = &data[first];
+  pPage->aDataOfst = &data[pPage->childPtrSize];
+  pPage->nOverflow = 0;
+  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
+  pPage->maskPage = (u16)(pBt->pageSize - 1);
+  pPage->nCell = 0;
+  pPage->isInit = 1;
+}
+
+
+/*
+** Convert a DbPage obtained from the pager into a MemPage used by
+** the btree layer.
+*/
+static MemPage *btreePageFromDbPage(DbPage *pDbPage, Pgno pgno, BtShared *pBt){
+  MemPage *pPage = (MemPage*)sqlite3PagerGetExtra(pDbPage);
+  if( pgno!=pPage->pgno ){
+    pPage->aData = sqlite3PagerGetData(pDbPage);
+    pPage->pDbPage = pDbPage;
+    pPage->pBt = pBt;
+    pPage->pgno = pgno;
+    pPage->hdrOffset = pgno==1 ? 100 : 0;
+  }
+  assert( pPage->aData==sqlite3PagerGetData(pDbPage) );
+  return pPage;
+}
+
+/*
+** Get a page from the pager.  Initialize the MemPage.pBt and
+** MemPage.aData elements if needed.  See also: btreeGetUnusedPage().
+**
+** If the PAGER_GET_NOCONTENT flag is set, it means that we do not care
+** about the content of the page at this time.  So do not go to the disk
+** to fetch the content.  Just fill in the content with zeros for now.
+** If in the future we call sqlite3PagerWrite() on this page, that
+** means we have started to be concerned about content and the disk
+** read should occur at that point.
+*/
+static int btreeGetPage(
+  BtShared *pBt,       /* The btree */
+  Pgno pgno,           /* Number of the page to fetch */
+  MemPage **ppPage,    /* Return the page in this parameter */
+  int flags            /* PAGER_GET_NOCONTENT or PAGER_GET_READONLY */
+){
+  int rc;
+  DbPage *pDbPage;
+
+  assert( flags==0 || flags==PAGER_GET_NOCONTENT || flags==PAGER_GET_READONLY );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  rc = sqlite3PagerGet(pBt->pPager, pgno, (DbPage**)&pDbPage, flags);
+  if( rc ) return rc;
+  *ppPage = btreePageFromDbPage(pDbPage, pgno, pBt);
+  return SQLITE_OK;
+}
+
+/*
+** Retrieve a page from the pager cache. If the requested page is not
+** already in the pager cache return NULL. Initialize the MemPage.pBt and
+** MemPage.aData elements if needed.
+*/
+static MemPage *btreePageLookup(BtShared *pBt, Pgno pgno){
+  DbPage *pDbPage;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  pDbPage = sqlite3PagerLookup(pBt->pPager, pgno);
+  if( pDbPage ){
+    return btreePageFromDbPage(pDbPage, pgno, pBt);
+  }
+  return 0;
+}
+
+/*
+** Return the size of the database file in pages. If there is any kind of
+** error, return ((unsigned int)-1).
+*/
+static Pgno btreePagecount(BtShared *pBt){
+  return pBt->nPage;
+}
+SQLITE_PRIVATE Pgno sqlite3BtreeLastPage(Btree *p){
+  assert( sqlite3BtreeHoldsMutex(p) );
+  return btreePagecount(p->pBt);
+}
+
+/*
+** Get a page from the pager and initialize it.
+*/
+static int getAndInitPage(
+  BtShared *pBt,                  /* The database file */
+  Pgno pgno,                      /* Number of the page to get */
+  MemPage **ppPage,               /* Write the page pointer here */
+  int bReadOnly                   /* True for a read-only page */
+){
+  int rc;
+  DbPage *pDbPage;
+  MemPage *pPage;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+
+  if( pgno>btreePagecount(pBt) ){
+    *ppPage = 0;
+    return SQLITE_CORRUPT_BKPT;
+  }
+  rc = sqlite3PagerGet(pBt->pPager, pgno, (DbPage**)&pDbPage, bReadOnly);
+  if( rc ){
+    *ppPage = 0;
+    return rc;
+  }
+  pPage = (MemPage*)sqlite3PagerGetExtra(pDbPage);
+  if( pPage->isInit==0 ){
+    btreePageFromDbPage(pDbPage, pgno, pBt);
+    rc = btreeInitPage(pPage);
+    if( rc!=SQLITE_OK ){
+      releasePage(pPage);
+      *ppPage = 0;
+      return rc;
+    }
+  }
+  assert( pPage->pgno==pgno || CORRUPT_DB );
+  assert( pPage->aData==sqlite3PagerGetData(pDbPage) );
+  *ppPage = pPage;
+  return SQLITE_OK;
+}
+
+/*
+** Release a MemPage.  This should be called once for each prior
+** call to btreeGetPage.
+**
+** Page1 is a special case and must be released using releasePageOne().
+*/
+static void releasePageNotNull(MemPage *pPage){
+  assert( pPage->aData );
+  assert( pPage->pBt );
+  assert( pPage->pDbPage!=0 );
+  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
+  assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  sqlite3PagerUnrefNotNull(pPage->pDbPage);
+}
+static void releasePage(MemPage *pPage){
+  if( pPage ) releasePageNotNull(pPage);
+}
+static void releasePageOne(MemPage *pPage){
+  assert( pPage!=0 );
+  assert( pPage->aData );
+  assert( pPage->pBt );
+  assert( pPage->pDbPage!=0 );
+  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
+  assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  sqlite3PagerUnrefPageOne(pPage->pDbPage);
+}
+
+/*
+** Get an unused page.
+**
+** This works just like btreeGetPage() with the addition:
+**
+**   *  If the page is already in use for some other purpose, immediately
+**      release it and return an SQLITE_CURRUPT error.
+**   *  Make sure the isInit flag is clear
+*/
+static int btreeGetUnusedPage(
+  BtShared *pBt,       /* The btree */
+  Pgno pgno,           /* Number of the page to fetch */
+  MemPage **ppPage,    /* Return the page in this parameter */
+  int flags            /* PAGER_GET_NOCONTENT or PAGER_GET_READONLY */
+){
+  int rc = btreeGetPage(pBt, pgno, ppPage, flags);
+  if( rc==SQLITE_OK ){
+    if( sqlite3PagerPageRefcount((*ppPage)->pDbPage)>1 ){
+      releasePage(*ppPage);
+      *ppPage = 0;
+      return SQLITE_CORRUPT_BKPT;
+    }
+    (*ppPage)->isInit = 0;
+  }else{
+    *ppPage = 0;
+  }
+  return rc;
+}
+
+
+/*
+** During a rollback, when the pager reloads information into the cache
+** so that the cache is restored to its original state at the start of
+** the transaction, for each page restored this routine is called.
+**
+** This routine needs to reset the extra data section at the end of the
+** page to agree with the restored data.
+*/
+static void pageReinit(DbPage *pData){
+  MemPage *pPage;
+  pPage = (MemPage *)sqlite3PagerGetExtra(pData);
+  assert( sqlite3PagerPageRefcount(pData)>0 );
+  if( pPage->isInit ){
+    assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+    pPage->isInit = 0;
+    if( sqlite3PagerPageRefcount(pData)>1 ){
+      /* pPage might not be a btree page;  it might be an overflow page
+      ** or ptrmap page or a free page.  In those cases, the following
+      ** call to btreeInitPage() will likely return SQLITE_CORRUPT.
+      ** But no harm is done by this.  And it is very important that
+      ** btreeInitPage() be called on every btree page so we make
+      ** the call for every page that comes in for re-initializing. */
+      btreeInitPage(pPage);
+    }
+  }
+}
+
+/*
+** Invoke the busy handler for a btree.
+*/
+static int btreeInvokeBusyHandler(void *pArg){
+  BtShared *pBt = (BtShared*)pArg;
+  assert( pBt->db );
+  assert( sqlite3_mutex_held(pBt->db->mutex) );
+  return sqlite3InvokeBusyHandler(&pBt->db->busyHandler);
+}
+
+/*
+** Open a database file.
+**
+** zFilename is the name of the database file.  If zFilename is NULL
+** then an ephemeral database is created.  The ephemeral database might
+** be exclusively in memory, or it might use a disk-based memory cache.
+** Either way, the ephemeral database will be automatically deleted
+** when sqlite3BtreeClose() is called.
+**
+** If zFilename is ":memory:" then an in-memory database is created
+** that is automatically destroyed when it is closed.
+**
+** The "flags" parameter is a bitmask that might contain bits like
+** BTREE_OMIT_JOURNAL and/or BTREE_MEMORY.
+**
+** If the database is already opened in the same database connection
+** and we are in shared cache mode, then the open will fail with an
+** SQLITE_CONSTRAINT error.  We cannot allow two or more BtShared
+** objects in the same database connection since doing so will lead
+** to problems with locking.
+*/
+SQLITE_PRIVATE int sqlite3BtreeOpen(
+  sqlite3_vfs *pVfs,      /* VFS to use for this b-tree */
+  const char *zFilename,  /* Name of the file containing the BTree database */
+  sqlite3 *db,            /* Associated database handle */
+  Btree **ppBtree,        /* Pointer to new Btree object written here */
+  int flags,              /* Options */
+  int vfsFlags            /* Flags passed through to sqlite3_vfs.xOpen() */
+){
+  BtShared *pBt = 0;             /* Shared part of btree structure */
+  Btree *p;                      /* Handle to return */
+  sqlite3_mutex *mutexOpen = 0;  /* Prevents a race condition. Ticket #3537 */
+  int rc = SQLITE_OK;            /* Result code from this function */
+  u8 nReserve;                   /* Byte of unused space on each page */
+  unsigned char zDbHeader[100];  /* Database header content */
+
+  /* True if opening an ephemeral, temporary database */
+  const int isTempDb = zFilename==0 || zFilename[0]==0;
+
+  /* Set the variable isMemdb to true for an in-memory database, or
+  ** false for a file-based database.
+  */
+#ifdef SQLITE_OMIT_MEMORYDB
+  const int isMemdb = 0;
+#else
+  const int isMemdb = (zFilename && strcmp(zFilename, ":memory:")==0)
+                       || (isTempDb && sqlite3TempInMemory(db))
+                       || (vfsFlags & SQLITE_OPEN_MEMORY)!=0;
+#endif
+
+  assert( db!=0 );
+  assert( pVfs!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( (flags&0xff)==flags );   /* flags fit in 8 bits */
+
+  /* Only a BTREE_SINGLE database can be BTREE_UNORDERED */
+  assert( (flags & BTREE_UNORDERED)==0 || (flags & BTREE_SINGLE)!=0 );
+
+  /* A BTREE_SINGLE database is always a temporary and/or ephemeral */
+  assert( (flags & BTREE_SINGLE)==0 || isTempDb );
+
+  if( isMemdb ){
+    flags |= BTREE_MEMORY;
+  }
+  if( (vfsFlags & SQLITE_OPEN_MAIN_DB)!=0 && (isMemdb || isTempDb) ){
+    vfsFlags = (vfsFlags & ~SQLITE_OPEN_MAIN_DB) | SQLITE_OPEN_TEMP_DB;
+  }
+  p = sqlite3MallocZero(sizeof(Btree));
+  if( !p ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  p->inTrans = TRANS_NONE;
+  p->db = db;
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  p->lock.pBtree = p;
+  p->lock.iTable = 1;
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
+  /*
+  ** If this Btree is a candidate for shared cache, try to find an
+  ** existing BtShared object that we can share with
+  */
+  if( isTempDb==0 && (isMemdb==0 || (vfsFlags&SQLITE_OPEN_URI)!=0) ){
+    if( vfsFlags & SQLITE_OPEN_SHAREDCACHE ){
+      int nFilename = sqlite3Strlen30(zFilename)+1;
+      int nFullPathname = pVfs->mxPathname+1;
+      char *zFullPathname = sqlite3Malloc(MAX(nFullPathname,nFilename));
+      MUTEX_LOGIC( sqlite3_mutex *mutexShared; )
+
+      p->sharable = 1;
+      if( !zFullPathname ){
+        sqlite3_free(p);
+        return SQLITE_NOMEM_BKPT;
+      }
+      if( isMemdb ){
+        memcpy(zFullPathname, zFilename, nFilename);
+      }else{
+        rc = sqlite3OsFullPathname(pVfs, zFilename,
+                                   nFullPathname, zFullPathname);
+        if( rc ){
+          if( rc==SQLITE_OK_SYMLINK ){
+            rc = SQLITE_OK;
+          }else{
+            sqlite3_free(zFullPathname);
+            sqlite3_free(p);
+            return rc;
+          }
+        }
+      }
+#if SQLITE_THREADSAFE
+      mutexOpen = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_OPEN);
+      sqlite3_mutex_enter(mutexOpen);
+      mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+      sqlite3_mutex_enter(mutexShared);
+#endif
+      for(pBt=GLOBAL(BtShared*,sqlite3SharedCacheList); pBt; pBt=pBt->pNext){
+        assert( pBt->nRef>0 );
+        if( 0==strcmp(zFullPathname, sqlite3PagerFilename(pBt->pPager, 0))
+                 && sqlite3PagerVfs(pBt->pPager)==pVfs ){
+          int iDb;
+          for(iDb=db->nDb-1; iDb>=0; iDb--){
+            Btree *pExisting = db->aDb[iDb].pBt;
+            if( pExisting && pExisting->pBt==pBt ){
+              sqlite3_mutex_leave(mutexShared);
+              sqlite3_mutex_leave(mutexOpen);
+              sqlite3_free(zFullPathname);
+              sqlite3_free(p);
+              return SQLITE_CONSTRAINT;
+            }
+          }
+          p->pBt = pBt;
+          pBt->nRef++;
+          break;
+        }
+      }
+      sqlite3_mutex_leave(mutexShared);
+      sqlite3_free(zFullPathname);
+    }
+#ifdef SQLITE_DEBUG
+    else{
+      /* In debug mode, we mark all persistent databases as sharable
+      ** even when they are not.  This exercises the locking code and
+      ** gives more opportunity for asserts(sqlite3_mutex_held())
+      ** statements to find locking problems.
+      */
+      p->sharable = 1;
+    }
+#endif
+  }
+#endif
+  if( pBt==0 ){
+    /*
+    ** The following asserts make sure that structures used by the btree are
+    ** the right size.  This is to guard against size changes that result
+    ** when compiling on a different architecture.
+    */
+    assert( sizeof(i64)==8 );
+    assert( sizeof(u64)==8 );
+    assert( sizeof(u32)==4 );
+    assert( sizeof(u16)==2 );
+    assert( sizeof(Pgno)==4 );
+
+    /* Suppress false-positive compiler warning from PVS-Studio */
+    memset(&zDbHeader[16], 0, 8);
+
+    pBt = sqlite3MallocZero( sizeof(*pBt) );
+    if( pBt==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto btree_open_out;
+    }
+    rc = sqlite3PagerOpen(pVfs, &pBt->pPager, zFilename,
+                          sizeof(MemPage), flags, vfsFlags, pageReinit);
+    if( rc==SQLITE_OK ){
+      sqlite3PagerSetMmapLimit(pBt->pPager, db->szMmap);
+      rc = sqlite3PagerReadFileheader(pBt->pPager,sizeof(zDbHeader),zDbHeader);
+    }
+    if( rc!=SQLITE_OK ){
+      goto btree_open_out;
+    }
+    pBt->openFlags = (u8)flags;
+    pBt->db = db;
+    sqlite3PagerSetBusyHandler(pBt->pPager, btreeInvokeBusyHandler, pBt);
+    p->pBt = pBt;
+
+    pBt->pCursor = 0;
+    pBt->pPage1 = 0;
+    if( sqlite3PagerIsreadonly(pBt->pPager) ) pBt->btsFlags |= BTS_READ_ONLY;
+#if defined(SQLITE_SECURE_DELETE)
+    pBt->btsFlags |= BTS_SECURE_DELETE;
+#elif defined(SQLITE_FAST_SECURE_DELETE)
+    pBt->btsFlags |= BTS_OVERWRITE;
+#endif
+    /* EVIDENCE-OF: R-51873-39618 The page size for a database file is
+    ** determined by the 2-byte integer located at an offset of 16 bytes from
+    ** the beginning of the database file. */
+    pBt->pageSize = (zDbHeader[16]<<8) | (zDbHeader[17]<<16);
+    if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
+         || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
+      pBt->pageSize = 0;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      /* If the magic name ":memory:" will create an in-memory database, then
+      ** leave the autoVacuum mode at 0 (do not auto-vacuum), even if
+      ** SQLITE_DEFAULT_AUTOVACUUM is true. On the other hand, if
+      ** SQLITE_OMIT_MEMORYDB has been defined, then ":memory:" is just a
+      ** regular file-name. In this case the auto-vacuum applies as per normal.
+      */
+      if( zFilename && !isMemdb ){
+        pBt->autoVacuum = (SQLITE_DEFAULT_AUTOVACUUM ? 1 : 0);
+        pBt->incrVacuum = (SQLITE_DEFAULT_AUTOVACUUM==2 ? 1 : 0);
+      }
+#endif
+      nReserve = 0;
+    }else{
+      /* EVIDENCE-OF: R-37497-42412 The size of the reserved region is
+      ** determined by the one-byte unsigned integer found at an offset of 20
+      ** into the database file header. */
+      nReserve = zDbHeader[20];
+      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
+      pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
+#endif
+    }
+    rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
+    if( rc ) goto btree_open_out;
+    pBt->usableSize = pBt->pageSize - nReserve;
+    assert( (pBt->pageSize & 7)==0 );  /* 8-byte alignment of pageSize */
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
+    /* Add the new BtShared object to the linked list sharable BtShareds.
+    */
+    pBt->nRef = 1;
+    if( p->sharable ){
+      MUTEX_LOGIC( sqlite3_mutex *mutexShared; )
+      MUTEX_LOGIC( mutexShared = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);)
+      if( SQLITE_THREADSAFE && sqlite3GlobalConfig.bCoreMutex ){
+        pBt->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_FAST);
+        if( pBt->mutex==0 ){
+          rc = SQLITE_NOMEM_BKPT;
+          goto btree_open_out;
+        }
+      }
+      sqlite3_mutex_enter(mutexShared);
+      pBt->pNext = GLOBAL(BtShared*,sqlite3SharedCacheList);
+      GLOBAL(BtShared*,sqlite3SharedCacheList) = pBt;
+      sqlite3_mutex_leave(mutexShared);
+    }
+#endif
+  }
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && !defined(SQLITE_OMIT_DISKIO)
+  /* If the new Btree uses a sharable pBtShared, then link the new
+  ** Btree into the list of all sharable Btrees for the same connection.
+  ** The list is kept in ascending order by pBt address.
+  */
+  if( p->sharable ){
+    int i;
+    Btree *pSib;
+    for(i=0; i<db->nDb; i++){
+      if( (pSib = db->aDb[i].pBt)!=0 && pSib->sharable ){
+        while( pSib->pPrev ){ pSib = pSib->pPrev; }
+        if( (uptr)p->pBt<(uptr)pSib->pBt ){
+          p->pNext = pSib;
+          p->pPrev = 0;
+          pSib->pPrev = p;
+        }else{
+          while( pSib->pNext && (uptr)pSib->pNext->pBt<(uptr)p->pBt ){
+            pSib = pSib->pNext;
+          }
+          p->pNext = pSib->pNext;
+          p->pPrev = pSib;
+          if( p->pNext ){
+            p->pNext->pPrev = p;
+          }
+          pSib->pNext = p;
+        }
+        break;
+      }
+    }
+  }
+#endif
+  *ppBtree = p;
+
+btree_open_out:
+  if( rc!=SQLITE_OK ){
+    if( pBt && pBt->pPager ){
+      sqlite3PagerClose(pBt->pPager, 0);
+    }
+    sqlite3_free(pBt);
+    sqlite3_free(p);
+    *ppBtree = 0;
+  }else{
+    sqlite3_file *pFile;
+
+    /* If the B-Tree was successfully opened, set the pager-cache size to the
+    ** default value. Except, when opening on an existing shared pager-cache,
+    ** do not change the pager-cache size.
+    */
+    if( sqlite3BtreeSchema(p, 0, 0)==0 ){
+      sqlite3BtreeSetCacheSize(p, SQLITE_DEFAULT_CACHE_SIZE);
+    }
+
+    pFile = sqlite3PagerFile(pBt->pPager);
+    if( pFile->pMethods ){
+      sqlite3OsFileControlHint(pFile, SQLITE_FCNTL_PDB, (void*)&pBt->db);
+    }
+  }
+  if( mutexOpen ){
+    assert( sqlite3_mutex_held(mutexOpen) );
+    sqlite3_mutex_leave(mutexOpen);
+  }
+  assert( rc!=SQLITE_OK || sqlite3BtreeConnectionCount(*ppBtree)>0 );
+  return rc;
+}
+
+/*
+** Decrement the BtShared.nRef counter.  When it reaches zero,
+** remove the BtShared structure from the sharing list.  Return
+** true if the BtShared.nRef counter reaches zero and return
+** false if it is still positive.
+*/
+static int removeFromSharingList(BtShared *pBt){
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  MUTEX_LOGIC( sqlite3_mutex *pMainMtx; )
+  BtShared *pList;
+  int removed = 0;
+
+  assert( sqlite3_mutex_notheld(pBt->mutex) );
+  MUTEX_LOGIC( pMainMtx = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  sqlite3_mutex_enter(pMainMtx);
+  pBt->nRef--;
+  if( pBt->nRef<=0 ){
+    if( GLOBAL(BtShared*,sqlite3SharedCacheList)==pBt ){
+      GLOBAL(BtShared*,sqlite3SharedCacheList) = pBt->pNext;
+    }else{
+      pList = GLOBAL(BtShared*,sqlite3SharedCacheList);
+      while( ALWAYS(pList) && pList->pNext!=pBt ){
+        pList=pList->pNext;
+      }
+      if( ALWAYS(pList) ){
+        pList->pNext = pBt->pNext;
+      }
+    }
+    if( SQLITE_THREADSAFE ){
+      sqlite3_mutex_free(pBt->mutex);
+    }
+    removed = 1;
+  }
+  sqlite3_mutex_leave(pMainMtx);
+  return removed;
+#else
+  return 1;
+#endif
+}
+
+/*
+** Make sure pBt->pTmpSpace points to an allocation of
+** MX_CELL_SIZE(pBt) bytes with a 4-byte prefix for a left-child
+** pointer.
+*/
+static SQLITE_NOINLINE int allocateTempSpace(BtShared *pBt){
+  assert( pBt!=0 );
+  assert( pBt->pTmpSpace==0 );
+  /* This routine is called only by btreeCursor() when allocating the
+  ** first write cursor for the BtShared object */
+  assert( pBt->pCursor!=0 && (pBt->pCursor->curFlags & BTCF_WriteFlag)!=0 );
+  pBt->pTmpSpace = sqlite3PageMalloc( pBt->pageSize );
+  if( pBt->pTmpSpace==0 ){
+    BtCursor *pCur = pBt->pCursor;
+    pBt->pCursor = pCur->pNext;  /* Unlink the cursor */
+    memset(pCur, 0, sizeof(*pCur));
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  /* One of the uses of pBt->pTmpSpace is to format cells before
+  ** inserting them into a leaf page (function fillInCell()). If
+  ** a cell is less than 4 bytes in size, it is rounded up to 4 bytes
+  ** by the various routines that manipulate binary cells. Which
+  ** can mean that fillInCell() only initializes the first 2 or 3
+  ** bytes of pTmpSpace, but that the first 4 bytes are copied from
+  ** it into a database page. This is not actually a problem, but it
+  ** does cause a valgrind error when the 1 or 2 bytes of uninitialized
+  ** data is passed to system call write(). So to avoid this error,
+  ** zero the first 4 bytes of temp space here.
+  **
+  ** Also:  Provide four bytes of initialized space before the
+  ** beginning of pTmpSpace as an area available to prepend the
+  ** left-child pointer to the beginning of a cell.
+  */
+  memset(pBt->pTmpSpace, 0, 8);
+  pBt->pTmpSpace += 4;
+  return SQLITE_OK;
+}
+
+/*
+** Free the pBt->pTmpSpace allocation
+*/
+static void freeTempSpace(BtShared *pBt){
+  if( pBt->pTmpSpace ){
+    pBt->pTmpSpace -= 4;
+    sqlite3PageFree(pBt->pTmpSpace);
+    pBt->pTmpSpace = 0;
+  }
+}
+
+/*
+** Close an open database and invalidate all cursors.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClose(Btree *p){
+  BtShared *pBt = p->pBt;
+
+  /* Close all cursors opened via this handle.  */
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+
+  /* Verify that no other cursors have this Btree open */
+#ifdef SQLITE_DEBUG
+  {
+    BtCursor *pCur = pBt->pCursor;
+    while( pCur ){
+      BtCursor *pTmp = pCur;
+      pCur = pCur->pNext;
+      assert( pTmp->pBtree!=p );
+
+    }
+  }
+#endif
+
+  /* Rollback any active transaction and free the handle structure.
+  ** The call to sqlite3BtreeRollback() drops any table-locks held by
+  ** this handle.
+  */
+  sqlite3BtreeRollback(p, SQLITE_OK, 0);
+  sqlite3BtreeLeave(p);
+
+  /* If there are still other outstanding references to the shared-btree
+  ** structure, return now. The remainder of this procedure cleans
+  ** up the shared-btree.
+  */
+  assert( p->wantToLock==0 && p->locked==0 );
+  if( !p->sharable || removeFromSharingList(pBt) ){
+    /* The pBt is no longer on the sharing list, so we can access
+    ** it without having to hold the mutex.
+    **
+    ** Clean out and delete the BtShared object.
+    */
+    assert( !pBt->pCursor );
+    sqlite3PagerClose(pBt->pPager, p->db);
+    if( pBt->xFreeSchema && pBt->pSchema ){
+      pBt->xFreeSchema(pBt->pSchema);
+    }
+    sqlite3DbFree(0, pBt->pSchema);
+    freeTempSpace(pBt);
+    sqlite3_free(pBt);
+  }
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  assert( p->wantToLock==0 );
+  assert( p->locked==0 );
+  if( p->pPrev ) p->pPrev->pNext = p->pNext;
+  if( p->pNext ) p->pNext->pPrev = p->pPrev;
+#endif
+
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Change the "soft" limit on the number of pages in the cache.
+** Unused and unmodified pages will be recycled when the number of
+** pages in the cache exceeds this soft limit.  But the size of the
+** cache is allowed to grow larger than this limit if it contains
+** dirty pages or pages still in active use.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree *p, int mxPage){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  sqlite3PagerSetCachesize(pBt->pPager, mxPage);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Change the "spill" limit on the number of pages in the cache.
+** If the number of pages exceeds this limit during a write transaction,
+** the pager might attempt to "spill" pages to the journal early in
+** order to free up memory.
+**
+** The value returned is the current spill size.  If zero is passed
+** as an argument, no changes are made to the spill size setting, so
+** using mxPage of 0 is a way to query the current spill size.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetSpillSize(Btree *p, int mxPage){
+  BtShared *pBt = p->pBt;
+  int res;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  res = sqlite3PagerSetSpillsize(pBt->pPager, mxPage);
+  sqlite3BtreeLeave(p);
+  return res;
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/*
+** Change the limit on the amount of the database file that may be
+** memory mapped.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetMmapLimit(Btree *p, sqlite3_int64 szMmap){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  sqlite3PagerSetMmapLimit(pBt->pPager, szMmap);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+#endif /* SQLITE_MAX_MMAP_SIZE>0 */
+
+/*
+** Change the way data is synced to disk in order to increase or decrease
+** how well the database resists damage due to OS crashes and power
+** failures.  Level 1 is the same as asynchronous (no syncs() occur and
+** there is a high probability of damage)  Level 2 is the default.  There
+** is a very low but non-zero probability of damage.  Level 3 reduces the
+** probability of damage to near zero but with a write performance reduction.
+*/
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+SQLITE_PRIVATE int sqlite3BtreeSetPagerFlags(
+  Btree *p,              /* The btree to set the safety level on */
+  unsigned pgFlags       /* Various PAGER_* flags */
+){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  sqlite3PagerSetFlags(pBt->pPager, pgFlags);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Change the default pages size and the number of reserved bytes per page.
+** Or, if the page size has already been fixed, return SQLITE_READONLY
+** without changing anything.
+**
+** The page size must be a power of 2 between 512 and 65536.  If the page
+** size supplied does not meet this constraint then the page size is not
+** changed.
+**
+** Page sizes are constrained to be a power of two so that the region
+** of the database file used for locking (beginning at PENDING_BYTE,
+** the first byte past the 1GB boundary, 0x40000000) needs to occur
+** at the beginning of a page.
+**
+** If parameter nReserve is less than zero, then the number of reserved
+** bytes per page is left unchanged.
+**
+** If the iFix!=0 then the BTS_PAGESIZE_FIXED flag is set so that the page size
+** and autovacuum mode can no longer be changed.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
+  int rc = SQLITE_OK;
+  int x;
+  BtShared *pBt = p->pBt;
+  assert( nReserve>=0 && nReserve<=255 );
+  sqlite3BtreeEnter(p);
+  pBt->nReserveWanted = nReserve;
+  x = pBt->pageSize - pBt->usableSize;
+  if( nReserve<x ) nReserve = x;
+  if( pBt->btsFlags & BTS_PAGESIZE_FIXED ){
+    sqlite3BtreeLeave(p);
+    return SQLITE_READONLY;
+  }
+  assert( nReserve>=0 && nReserve<=255 );
+  if( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE &&
+        ((pageSize-1)&pageSize)==0 ){
+    assert( (pageSize & 7)==0 );
+    assert( !pBt->pCursor );
+    if( nReserve>32 && pageSize==512 ) pageSize = 1024;
+    pBt->pageSize = (u32)pageSize;
+    freeTempSpace(pBt);
+  }
+  rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
+  pBt->usableSize = pBt->pageSize - (u16)nReserve;
+  if( iFix ) pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Return the currently defined page size
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetPageSize(Btree *p){
+  return p->pBt->pageSize;
+}
+
+/*
+** This function is similar to sqlite3BtreeGetReserve(), except that it
+** may only be called if it is guaranteed that the b-tree mutex is already
+** held.
+**
+** This is useful in one special case in the backup API code where it is
+** known that the shared b-tree mutex is held, but the mutex on the
+** database handle that owns *p is not. In this case if sqlite3BtreeEnter()
+** were to be called, it might collide with some other operation on the
+** database handle that owns *p, causing undefined behavior.
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetReserveNoMutex(Btree *p){
+  int n;
+  assert( sqlite3_mutex_held(p->pBt->mutex) );
+  n = p->pBt->pageSize - p->pBt->usableSize;
+  return n;
+}
+
+/*
+** Return the number of bytes of space at the end of every page that
+** are intentionally left unused.  This is the "reserved" space that is
+** sometimes used by extensions.
+**
+** The value returned is the larger of the current reserve size and
+** the latest reserve size requested by SQLITE_FILECTRL_RESERVE_BYTES.
+** The amount of reserve can only grow - never shrink.
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetRequestedReserve(Btree *p){
+  int n1, n2;
+  sqlite3BtreeEnter(p);
+  n1 = (int)p->pBt->nReserveWanted;
+  n2 = sqlite3BtreeGetReserveNoMutex(p);
+  sqlite3BtreeLeave(p);
+  return n1>n2 ? n1 : n2;
+}
+
+
+/*
+** Set the maximum page count for a database if mxPage is positive.
+** No changes are made if mxPage is 0 or negative.
+** Regardless of the value of mxPage, return the maximum page count.
+*/
+SQLITE_PRIVATE Pgno sqlite3BtreeMaxPageCount(Btree *p, Pgno mxPage){
+  Pgno n;
+  sqlite3BtreeEnter(p);
+  n = sqlite3PagerMaxPageCount(p->pBt->pPager, mxPage);
+  sqlite3BtreeLeave(p);
+  return n;
+}
+
+/*
+** Change the values for the BTS_SECURE_DELETE and BTS_OVERWRITE flags:
+**
+**    newFlag==0       Both BTS_SECURE_DELETE and BTS_OVERWRITE are cleared
+**    newFlag==1       BTS_SECURE_DELETE set and BTS_OVERWRITE is cleared
+**    newFlag==2       BTS_SECURE_DELETE cleared and BTS_OVERWRITE is set
+**    newFlag==(-1)    No changes
+**
+** This routine acts as a query if newFlag is less than zero
+**
+** With BTS_OVERWRITE set, deleted content is overwritten by zeros, but
+** freelist leaf pages are not written back to the database.  Thus in-page
+** deleted content is cleared, but freelist deleted content is not.
+**
+** With BTS_SECURE_DELETE, operation is like BTS_OVERWRITE with the addition
+** that freelist leaf pages are written back into the database, increasing
+** the amount of disk I/O.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSecureDelete(Btree *p, int newFlag){
+  int b;
+  if( p==0 ) return 0;
+  sqlite3BtreeEnter(p);
+  assert( BTS_OVERWRITE==BTS_SECURE_DELETE*2 );
+  assert( BTS_FAST_SECURE==(BTS_OVERWRITE|BTS_SECURE_DELETE) );
+  if( newFlag>=0 ){
+    p->pBt->btsFlags &= ~BTS_FAST_SECURE;
+    p->pBt->btsFlags |= BTS_SECURE_DELETE*newFlag;
+  }
+  b = (p->pBt->btsFlags & BTS_FAST_SECURE)/BTS_SECURE_DELETE;
+  sqlite3BtreeLeave(p);
+  return b;
+}
+
+/*
+** Change the 'auto-vacuum' property of the database. If the 'autoVacuum'
+** parameter is non-zero, then auto-vacuum mode is enabled. If zero, it
+** is disabled. The default value for the auto-vacuum property is
+** determined by the SQLITE_DEFAULT_AUTOVACUUM macro.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetAutoVacuum(Btree *p, int autoVacuum){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  return SQLITE_READONLY;
+#else
+  BtShared *pBt = p->pBt;
+  int rc = SQLITE_OK;
+  u8 av = (u8)autoVacuum;
+
+  sqlite3BtreeEnter(p);
+  if( (pBt->btsFlags & BTS_PAGESIZE_FIXED)!=0 && (av ?1:0)!=pBt->autoVacuum ){
+    rc = SQLITE_READONLY;
+  }else{
+    pBt->autoVacuum = av ?1:0;
+    pBt->incrVacuum = av==2 ?1:0;
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+#endif
+}
+
+/*
+** Return the value of the 'auto-vacuum' property. If auto-vacuum is
+** enabled 1 is returned. Otherwise 0.
+*/
+SQLITE_PRIVATE int sqlite3BtreeGetAutoVacuum(Btree *p){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  return BTREE_AUTOVACUUM_NONE;
+#else
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = (
+    (!p->pBt->autoVacuum)?BTREE_AUTOVACUUM_NONE:
+    (!p->pBt->incrVacuum)?BTREE_AUTOVACUUM_FULL:
+    BTREE_AUTOVACUUM_INCR
+  );
+  sqlite3BtreeLeave(p);
+  return rc;
+#endif
+}
+
+/*
+** If the user has not set the safety-level for this database connection
+** using "PRAGMA synchronous", and if the safety-level is not already
+** set to the value passed to this function as the second parameter,
+** set it so.
+*/
+#if SQLITE_DEFAULT_SYNCHRONOUS!=SQLITE_DEFAULT_WAL_SYNCHRONOUS \
+    && !defined(SQLITE_OMIT_WAL)
+static void setDefaultSyncFlag(BtShared *pBt, u8 safety_level){
+  sqlite3 *db;
+  Db *pDb;
+  if( (db=pBt->db)!=0 && (pDb=db->aDb)!=0 ){
+    while( pDb->pBt==0 || pDb->pBt->pBt!=pBt ){ pDb++; }
+    if( pDb->bSyncSet==0
+     && pDb->safety_level!=safety_level
+     && pDb!=&db->aDb[1]
+    ){
+      pDb->safety_level = safety_level;
+      sqlite3PagerSetFlags(pBt->pPager,
+          pDb->safety_level | (db->flags & PAGER_FLAGS_MASK));
+    }
+  }
+}
+#else
+# define setDefaultSyncFlag(pBt,safety_level)
+#endif
+
+/* Forward declaration */
+static int newDatabase(BtShared*);
+
+
+/*
+** Get a reference to pPage1 of the database file.  This will
+** also acquire a readlock on that file.
+**
+** SQLITE_OK is returned on success.  If the file is not a
+** well-formed database file, then SQLITE_CORRUPT is returned.
+** SQLITE_BUSY is returned if the database is locked.  SQLITE_NOMEM
+** is returned if we run out of memory.
+*/
+static int lockBtree(BtShared *pBt){
+  int rc;              /* Result code from subfunctions */
+  MemPage *pPage1;     /* Page 1 of the database file */
+  u32 nPage;           /* Number of pages in the database */
+  u32 nPageFile = 0;   /* Number of pages in the database file */
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pBt->pPage1==0 );
+  rc = sqlite3PagerSharedLock(pBt->pPager);
+  if( rc!=SQLITE_OK ) return rc;
+  rc = btreeGetPage(pBt, 1, &pPage1, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Do some checking to help insure the file we opened really is
+  ** a valid database file.
+  */
+  nPage = get4byte(28+(u8*)pPage1->aData);
+  sqlite3PagerPagecount(pBt->pPager, (int*)&nPageFile);
+  if( nPage==0 || memcmp(24+(u8*)pPage1->aData, 92+(u8*)pPage1->aData,4)!=0 ){
+    nPage = nPageFile;
+  }
+  if( (pBt->db->flags & SQLITE_ResetDatabase)!=0 ){
+    nPage = 0;
+  }
+  if( nPage>0 ){
+    u32 pageSize;
+    u32 usableSize;
+    u8 *page1 = pPage1->aData;
+    rc = SQLITE_NOTADB;
+    /* EVIDENCE-OF: R-43737-39999 Every valid SQLite database file begins
+    ** with the following 16 bytes (in hex): 53 51 4c 69 74 65 20 66 6f 72 6d
+    ** 61 74 20 33 00. */
+    if( memcmp(page1, zMagicHeader, 16)!=0 ){
+      goto page1_init_failed;
+    }
+
+#ifdef SQLITE_OMIT_WAL
+    if( page1[18]>1 ){
+      pBt->btsFlags |= BTS_READ_ONLY;
+    }
+    if( page1[19]>1 ){
+      goto page1_init_failed;
+    }
+#else
+    if( page1[18]>2 ){
+      pBt->btsFlags |= BTS_READ_ONLY;
+    }
+    if( page1[19]>2 ){
+      goto page1_init_failed;
+    }
+
+    /* If the read version is set to 2, this database should be accessed
+    ** in WAL mode. If the log is not already open, open it now. Then
+    ** return SQLITE_OK and return without populating BtShared.pPage1.
+    ** The caller detects this and calls this function again. This is
+    ** required as the version of page 1 currently in the page1 buffer
+    ** may not be the latest version - there may be a newer one in the log
+    ** file.
+    */
+    if( page1[19]==2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
+      int isOpen = 0;
+      rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
+      if( rc!=SQLITE_OK ){
+        goto page1_init_failed;
+      }else{
+        setDefaultSyncFlag(pBt, SQLITE_DEFAULT_WAL_SYNCHRONOUS+1);
+        if( isOpen==0 ){
+          releasePageOne(pPage1);
+          return SQLITE_OK;
+        }
+      }
+      rc = SQLITE_NOTADB;
+    }else{
+      setDefaultSyncFlag(pBt, SQLITE_DEFAULT_SYNCHRONOUS+1);
+    }
+#endif
+
+    /* EVIDENCE-OF: R-15465-20813 The maximum and minimum embedded payload
+    ** fractions and the leaf payload fraction values must be 64, 32, and 32.
+    **
+    ** The original design allowed these amounts to vary, but as of
+    ** version 3.6.0, we require them to be fixed.
+    */
+    if( memcmp(&page1[21], "\100\040\040",3)!=0 ){
+      goto page1_init_failed;
+    }
+    /* EVIDENCE-OF: R-51873-39618 The page size for a database file is
+    ** determined by the 2-byte integer located at an offset of 16 bytes from
+    ** the beginning of the database file. */
+    pageSize = (page1[16]<<8) | (page1[17]<<16);
+    /* EVIDENCE-OF: R-25008-21688 The size of a page is a power of two
+    ** between 512 and 65536 inclusive. */
+    if( ((pageSize-1)&pageSize)!=0
+     || pageSize>SQLITE_MAX_PAGE_SIZE
+     || pageSize<=256
+    ){
+      goto page1_init_failed;
+    }
+    assert( (pageSize & 7)==0 );
+    /* EVIDENCE-OF: R-59310-51205 The "reserved space" size in the 1-byte
+    ** integer at offset 20 is the number of bytes of space at the end of
+    ** each page to reserve for extensions.
+    **
+    ** EVIDENCE-OF: R-37497-42412 The size of the reserved region is
+    ** determined by the one-byte unsigned integer found at an offset of 20
+    ** into the database file header. */
+    usableSize = pageSize - page1[20];
+    if( (u32)pageSize!=pBt->pageSize ){
+      /* After reading the first page of the database assuming a page size
+      ** of BtShared.pageSize, we have discovered that the page-size is
+      ** actually pageSize. Unlock the database, leave pBt->pPage1 at
+      ** zero and return SQLITE_OK. The caller will call this function
+      ** again with the correct page-size.
+      */
+      releasePageOne(pPage1);
+      pBt->usableSize = usableSize;
+      pBt->pageSize = pageSize;
+      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+      freeTempSpace(pBt);
+      rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize,
+                                   pageSize-usableSize);
+      return rc;
+    }
+    if( nPage>nPageFile ){
+      if( sqlite3WritableSchema(pBt->db)==0 ){
+        rc = SQLITE_CORRUPT_BKPT;
+        goto page1_init_failed;
+      }else{
+        nPage = nPageFile;
+      }
+    }
+    /* EVIDENCE-OF: R-28312-64704 However, the usable size is not allowed to
+    ** be less than 480. In other words, if the page size is 512, then the
+    ** reserved space size cannot exceed 32. */
+    if( usableSize<480 ){
+      goto page1_init_failed;
+    }
+    pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+    pBt->pageSize = pageSize;
+    pBt->usableSize = usableSize;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    pBt->autoVacuum = (get4byte(&page1[36 + 4*4])?1:0);
+    pBt->incrVacuum = (get4byte(&page1[36 + 7*4])?1:0);
+#endif
+  }
+
+  /* maxLocal is the maximum amount of payload to store locally for
+  ** a cell.  Make sure it is small enough so that at least minFanout
+  ** cells can will fit on one page.  We assume a 10-byte page header.
+  ** Besides the payload, the cell must store:
+  **     2-byte pointer to the cell
+  **     4-byte child pointer
+  **     9-byte nKey value
+  **     4-byte nData value
+  **     4-byte overflow page pointer
+  ** So a cell consists of a 2-byte pointer, a header which is as much as
+  ** 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow
+  ** page pointer.
+  */
+  pBt->maxLocal = (u16)((pBt->usableSize-12)*64/255 - 23);
+  pBt->minLocal = (u16)((pBt->usableSize-12)*32/255 - 23);
+  pBt->maxLeaf = (u16)(pBt->usableSize - 35);
+  pBt->minLeaf = (u16)((pBt->usableSize-12)*32/255 - 23);
+  if( pBt->maxLocal>127 ){
+    pBt->max1bytePayload = 127;
+  }else{
+    pBt->max1bytePayload = (u8)pBt->maxLocal;
+  }
+  assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) );
+  pBt->pPage1 = pPage1;
+  pBt->nPage = nPage;
+  return SQLITE_OK;
+
+page1_init_failed:
+  releasePageOne(pPage1);
+  pBt->pPage1 = 0;
+  return rc;
+}
+
+#ifndef NDEBUG
+/*
+** Return the number of cursors open on pBt. This is for use
+** in assert() expressions, so it is only compiled if NDEBUG is not
+** defined.
+**
+** Only write cursors are counted if wrOnly is true.  If wrOnly is
+** false then all cursors are counted.
+**
+** For the purposes of this routine, a cursor is any cursor that
+** is capable of reading or writing to the database.  Cursors that
+** have been tripped into the CURSOR_FAULT state are not counted.
+*/
+static int countValidCursors(BtShared *pBt, int wrOnly){
+  BtCursor *pCur;
+  int r = 0;
+  for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
+    if( (wrOnly==0 || (pCur->curFlags & BTCF_WriteFlag)!=0)
+     && pCur->eState!=CURSOR_FAULT ) r++;
+  }
+  return r;
+}
+#endif
+
+/*
+** If there are no outstanding cursors and we are not in the middle
+** of a transaction but there is a read lock on the database, then
+** this routine unrefs the first page of the database file which
+** has the effect of releasing the read lock.
+**
+** If there is a transaction in progress, this routine is a no-op.
+*/
+static void unlockBtreeIfUnused(BtShared *pBt){
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( countValidCursors(pBt,0)==0 || pBt->inTransaction>TRANS_NONE );
+  if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){
+    MemPage *pPage1 = pBt->pPage1;
+    assert( pPage1->aData );
+    assert( sqlite3PagerRefcount(pBt->pPager)==1 );
+    pBt->pPage1 = 0;
+    releasePageOne(pPage1);
+  }
+}
+
+/*
+** If pBt points to an empty file then convert that empty file
+** into a new empty database by initializing the first page of
+** the database.
+*/
+static int newDatabase(BtShared *pBt){
+  MemPage *pP1;
+  unsigned char *data;
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pBt->nPage>0 ){
+    return SQLITE_OK;
+  }
+  pP1 = pBt->pPage1;
+  assert( pP1!=0 );
+  data = pP1->aData;
+  rc = sqlite3PagerWrite(pP1->pDbPage);
+  if( rc ) return rc;
+  memcpy(data, zMagicHeader, sizeof(zMagicHeader));
+  assert( sizeof(zMagicHeader)==16 );
+  data[16] = (u8)((pBt->pageSize>>8)&0xff);
+  data[17] = (u8)((pBt->pageSize>>16)&0xff);
+  data[18] = 1;
+  data[19] = 1;
+  assert( pBt->usableSize<=pBt->pageSize && pBt->usableSize+255>=pBt->pageSize);
+  data[20] = (u8)(pBt->pageSize - pBt->usableSize);
+  data[21] = 64;
+  data[22] = 32;
+  data[23] = 32;
+  memset(&data[24], 0, 100-24);
+  zeroPage(pP1, PTF_INTKEY|PTF_LEAF|PTF_LEAFDATA );
+  pBt->btsFlags |= BTS_PAGESIZE_FIXED;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  assert( pBt->autoVacuum==1 || pBt->autoVacuum==0 );
+  assert( pBt->incrVacuum==1 || pBt->incrVacuum==0 );
+  put4byte(&data[36 + 4*4], pBt->autoVacuum);
+  put4byte(&data[36 + 7*4], pBt->incrVacuum);
+#endif
+  pBt->nPage = 1;
+  data[31] = 1;
+  return SQLITE_OK;
+}
+
+/*
+** Initialize the first page of the database file (creating a database
+** consisting of a single page and no schema objects). Return SQLITE_OK
+** if successful, or an SQLite error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3BtreeNewDb(Btree *p){
+  int rc;
+  sqlite3BtreeEnter(p);
+  p->pBt->nPage = 0;
+  rc = newDatabase(p->pBt);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Attempt to start a new transaction. A write-transaction
+** is started if the second argument is nonzero, otherwise a read-
+** transaction.  If the second argument is 2 or more and exclusive
+** transaction is started, meaning that no other process is allowed
+** to access the database.  A preexisting transaction may not be
+** upgraded to exclusive by calling this routine a second time - the
+** exclusivity flag only works for a new transaction.
+**
+** A write-transaction must be started before attempting any
+** changes to the database.  None of the following routines
+** will work unless a transaction is started first:
+**
+**      sqlite3BtreeCreateTable()
+**      sqlite3BtreeCreateIndex()
+**      sqlite3BtreeClearTable()
+**      sqlite3BtreeDropTable()
+**      sqlite3BtreeInsert()
+**      sqlite3BtreeDelete()
+**      sqlite3BtreeUpdateMeta()
+**
+** If an initial attempt to acquire the lock fails because of lock contention
+** and the database was previously unlocked, then invoke the busy handler
+** if there is one.  But if there was previously a read-lock, do not
+** invoke the busy handler - just return SQLITE_BUSY.  SQLITE_BUSY is
+** returned when there is already a read-lock in order to avoid a deadlock.
+**
+** Suppose there are two processes A and B.  A has a read lock and B has
+** a reserved lock.  B tries to promote to exclusive but is blocked because
+** of A's read lock.  A tries to promote to reserved but is blocked by B.
+** One or the other of the two processes must give way or there can be
+** no progress.  By returning SQLITE_BUSY and not invoking the busy callback
+** when A already has a read lock, we encourage A to give up and let B
+** proceed.
+*/
+static SQLITE_NOINLINE int btreeBeginTrans(
+  Btree *p,                 /* The btree in which to start the transaction */
+  int wrflag,               /* True to start a write transaction */
+  int *pSchemaVersion       /* Put schema version number here, if not NULL */
+){
+  BtShared *pBt = p->pBt;
+  Pager *pPager = pBt->pPager;
+  int rc = SQLITE_OK;
+
+  sqlite3BtreeEnter(p);
+  btreeIntegrity(p);
+
+  /* If the btree is already in a write-transaction, or it
+  ** is already in a read-transaction and a read-transaction
+  ** is requested, this is a no-op.
+  */
+  if( p->inTrans==TRANS_WRITE || (p->inTrans==TRANS_READ && !wrflag) ){
+    goto trans_begun;
+  }
+  assert( pBt->inTransaction==TRANS_WRITE || IfNotOmitAV(pBt->bDoTruncate)==0 );
+
+  if( (p->db->flags & SQLITE_ResetDatabase)
+   && sqlite3PagerIsreadonly(pPager)==0
+  ){
+    pBt->btsFlags &= ~BTS_READ_ONLY;
+  }
+
+  /* Write transactions are not possible on a read-only database */
+  if( (pBt->btsFlags & BTS_READ_ONLY)!=0 && wrflag ){
+    rc = SQLITE_READONLY;
+    goto trans_begun;
+  }
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  {
+    sqlite3 *pBlock = 0;
+    /* If another database handle has already opened a write transaction
+    ** on this shared-btree structure and a second write transaction is
+    ** requested, return SQLITE_LOCKED.
+    */
+    if( (wrflag && pBt->inTransaction==TRANS_WRITE)
+     || (pBt->btsFlags & BTS_PENDING)!=0
+    ){
+      pBlock = pBt->pWriter->db;
+    }else if( wrflag>1 ){
+      BtLock *pIter;
+      for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
+        if( pIter->pBtree!=p ){
+          pBlock = pIter->pBtree->db;
+          break;
+        }
+      }
+    }
+    if( pBlock ){
+      sqlite3ConnectionBlocked(p->db, pBlock);
+      rc = SQLITE_LOCKED_SHAREDCACHE;
+      goto trans_begun;
+    }
+  }
+#endif
+
+  /* Any read-only or read-write transaction implies a read-lock on
+  ** page 1. So if some other shared-cache client already has a write-lock
+  ** on page 1, the transaction cannot be opened. */
+  rc = querySharedCacheTableLock(p, SCHEMA_ROOT, READ_LOCK);
+  if( SQLITE_OK!=rc ) goto trans_begun;
+
+  pBt->btsFlags &= ~BTS_INITIALLY_EMPTY;
+  if( pBt->nPage==0 ) pBt->btsFlags |= BTS_INITIALLY_EMPTY;
+  do {
+    sqlite3PagerWalDb(pPager, p->db);
+
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+    /* If transitioning from no transaction directly to a write transaction,
+    ** block for the WRITER lock first if possible. */
+    if( pBt->pPage1==0 && wrflag ){
+      assert( pBt->inTransaction==TRANS_NONE );
+      rc = sqlite3PagerWalWriteLock(pPager, 1);
+      if( rc!=SQLITE_BUSY && rc!=SQLITE_OK ) break;
+    }
+#endif
+
+    /* Call lockBtree() until either pBt->pPage1 is populated or
+    ** lockBtree() returns something other than SQLITE_OK. lockBtree()
+    ** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
+    ** reading page 1 it discovers that the page-size of the database
+    ** file is not pBt->pageSize. In this case lockBtree() will update
+    ** pBt->pageSize to the page-size of the file on disk.
+    */
+    while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );
+
+    if( rc==SQLITE_OK && wrflag ){
+      if( (pBt->btsFlags & BTS_READ_ONLY)!=0 ){
+        rc = SQLITE_READONLY;
+      }else{
+        rc = sqlite3PagerBegin(pPager, wrflag>1, sqlite3TempInMemory(p->db));
+        if( rc==SQLITE_OK ){
+          rc = newDatabase(pBt);
+        }else if( rc==SQLITE_BUSY_SNAPSHOT && pBt->inTransaction==TRANS_NONE ){
+          /* if there was no transaction opened when this function was
+          ** called and SQLITE_BUSY_SNAPSHOT is returned, change the error
+          ** code to SQLITE_BUSY. */
+          rc = SQLITE_BUSY;
+        }
+      }
+    }
+
+    if( rc!=SQLITE_OK ){
+      (void)sqlite3PagerWalWriteLock(pPager, 0);
+      unlockBtreeIfUnused(pBt);
+    }
+  }while( (rc&0xFF)==SQLITE_BUSY && pBt->inTransaction==TRANS_NONE &&
+          btreeInvokeBusyHandler(pBt) );
+  sqlite3PagerWalDb(pPager, 0);
+#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
+  if( rc==SQLITE_BUSY_TIMEOUT ) rc = SQLITE_BUSY;
+#endif
+
+  if( rc==SQLITE_OK ){
+    if( p->inTrans==TRANS_NONE ){
+      pBt->nTransaction++;
+#ifndef SQLITE_OMIT_SHARED_CACHE
+      if( p->sharable ){
+        assert( p->lock.pBtree==p && p->lock.iTable==1 );
+        p->lock.eLock = READ_LOCK;
+        p->lock.pNext = pBt->pLock;
+        pBt->pLock = &p->lock;
+      }
+#endif
+    }
+    p->inTrans = (wrflag?TRANS_WRITE:TRANS_READ);
+    if( p->inTrans>pBt->inTransaction ){
+      pBt->inTransaction = p->inTrans;
+    }
+    if( wrflag ){
+      MemPage *pPage1 = pBt->pPage1;
+#ifndef SQLITE_OMIT_SHARED_CACHE
+      assert( !pBt->pWriter );
+      pBt->pWriter = p;
+      pBt->btsFlags &= ~BTS_EXCLUSIVE;
+      if( wrflag>1 ) pBt->btsFlags |= BTS_EXCLUSIVE;
+#endif
+
+      /* If the db-size header field is incorrect (as it may be if an old
+      ** client has been writing the database file), update it now. Doing
+      ** this sooner rather than later means the database size can safely
+      ** re-read the database size from page 1 if a savepoint or transaction
+      ** rollback occurs within the transaction.
+      */
+      if( pBt->nPage!=get4byte(&pPage1->aData[28]) ){
+        rc = sqlite3PagerWrite(pPage1->pDbPage);
+        if( rc==SQLITE_OK ){
+          put4byte(&pPage1->aData[28], pBt->nPage);
+        }
+      }
+    }
+  }
+
+trans_begun:
+  if( rc==SQLITE_OK ){
+    if( pSchemaVersion ){
+      *pSchemaVersion = get4byte(&pBt->pPage1->aData[40]);
+    }
+    if( wrflag ){
+      /* This call makes sure that the pager has the correct number of
+      ** open savepoints. If the second parameter is greater than 0 and
+      ** the sub-journal is not already open, then it will be opened here.
+      */
+      rc = sqlite3PagerOpenSavepoint(pPager, p->db->nSavepoint);
+    }
+  }
+
+  btreeIntegrity(p);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag, int *pSchemaVersion){
+  BtShared *pBt;
+  if( p->sharable
+   || p->inTrans==TRANS_NONE
+   || (p->inTrans==TRANS_READ && wrflag!=0)
+  ){
+    return btreeBeginTrans(p,wrflag,pSchemaVersion);
+  }
+  pBt = p->pBt;
+  if( pSchemaVersion ){
+    *pSchemaVersion = get4byte(&pBt->pPage1->aData[40]);
+  }
+  if( wrflag ){
+    /* This call makes sure that the pager has the correct number of
+    ** open savepoints. If the second parameter is greater than 0 and
+    ** the sub-journal is not already open, then it will be opened here.
+    */
+    return sqlite3PagerOpenSavepoint(pBt->pPager, p->db->nSavepoint);
+  }else{
+    return SQLITE_OK;
+  }
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+
+/*
+** Set the pointer-map entries for all children of page pPage. Also, if
+** pPage contains cells that point to overflow pages, set the pointer
+** map entries for the overflow pages as well.
+*/
+static int setChildPtrmaps(MemPage *pPage){
+  int i;                             /* Counter variable */
+  int nCell;                         /* Number of cells in page pPage */
+  int rc;                            /* Return code */
+  BtShared *pBt = pPage->pBt;
+  Pgno pgno = pPage->pgno;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  rc = pPage->isInit ? SQLITE_OK : btreeInitPage(pPage);
+  if( rc!=SQLITE_OK ) return rc;
+  nCell = pPage->nCell;
+
+  for(i=0; i<nCell; i++){
+    u8 *pCell = findCell(pPage, i);
+
+    ptrmapPutOvflPtr(pPage, pPage, pCell, &rc);
+
+    if( !pPage->leaf ){
+      Pgno childPgno = get4byte(pCell);
+      ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno, &rc);
+    }
+  }
+
+  if( !pPage->leaf ){
+    Pgno childPgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    ptrmapPut(pBt, childPgno, PTRMAP_BTREE, pgno, &rc);
+  }
+
+  return rc;
+}
+
+/*
+** Somewhere on pPage is a pointer to page iFrom.  Modify this pointer so
+** that it points to iTo. Parameter eType describes the type of pointer to
+** be modified, as  follows:
+**
+** PTRMAP_BTREE:     pPage is a btree-page. The pointer points at a child
+**                   page of pPage.
+**
+** PTRMAP_OVERFLOW1: pPage is a btree-page. The pointer points at an overflow
+**                   page pointed to by one of the cells on pPage.
+**
+** PTRMAP_OVERFLOW2: pPage is an overflow-page. The pointer points at the next
+**                   overflow page in the list.
+*/
+static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  if( eType==PTRMAP_OVERFLOW2 ){
+    /* The pointer is always the first 4 bytes of the page in this case.  */
+    if( get4byte(pPage->aData)!=iFrom ){
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    put4byte(pPage->aData, iTo);
+  }else{
+    int i;
+    int nCell;
+    int rc;
+
+    rc = pPage->isInit ? SQLITE_OK : btreeInitPage(pPage);
+    if( rc ) return rc;
+    nCell = pPage->nCell;
+
+    for(i=0; i<nCell; i++){
+      u8 *pCell = findCell(pPage, i);
+      if( eType==PTRMAP_OVERFLOW1 ){
+        CellInfo info;
+        pPage->xParseCell(pPage, pCell, &info);
+        if( info.nLocal<info.nPayload ){
+          if( pCell+info.nSize > pPage->aData+pPage->pBt->usableSize ){
+            return SQLITE_CORRUPT_PAGE(pPage);
+          }
+          if( iFrom==get4byte(pCell+info.nSize-4) ){
+            put4byte(pCell+info.nSize-4, iTo);
+            break;
+          }
+        }
+      }else{
+        if( pCell+4 > pPage->aData+pPage->pBt->usableSize ){
+          return SQLITE_CORRUPT_PAGE(pPage);
+        }
+        if( get4byte(pCell)==iFrom ){
+          put4byte(pCell, iTo);
+          break;
+        }
+      }
+    }
+
+    if( i==nCell ){
+      if( eType!=PTRMAP_BTREE ||
+          get4byte(&pPage->aData[pPage->hdrOffset+8])!=iFrom ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      put4byte(&pPage->aData[pPage->hdrOffset+8], iTo);
+    }
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** Move the open database page pDbPage to location iFreePage in the
+** database. The pDbPage reference remains valid.
+**
+** The isCommit flag indicates that there is no need to remember that
+** the journal needs to be sync()ed before database page pDbPage->pgno
+** can be written to. The caller has already promised not to write to that
+** page.
+*/
+static int relocatePage(
+  BtShared *pBt,           /* Btree */
+  MemPage *pDbPage,        /* Open page to move */
+  u8 eType,                /* Pointer map 'type' entry for pDbPage */
+  Pgno iPtrPage,           /* Pointer map 'page-no' entry for pDbPage */
+  Pgno iFreePage,          /* The location to move pDbPage to */
+  int isCommit             /* isCommit flag passed to sqlite3PagerMovepage */
+){
+  MemPage *pPtrPage;   /* The page that contains a pointer to pDbPage */
+  Pgno iDbPage = pDbPage->pgno;
+  Pager *pPager = pBt->pPager;
+  int rc;
+
+  assert( eType==PTRMAP_OVERFLOW2 || eType==PTRMAP_OVERFLOW1 ||
+      eType==PTRMAP_BTREE || eType==PTRMAP_ROOTPAGE );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( pDbPage->pBt==pBt );
+  if( iDbPage<3 ) return SQLITE_CORRUPT_BKPT;
+
+  /* Move page iDbPage from its current location to page number iFreePage */
+  TRACE(("AUTOVACUUM: Moving %u to free page %u (ptr page %u type %u)\n",
+      iDbPage, iFreePage, iPtrPage, eType));
+  rc = sqlite3PagerMovepage(pPager, pDbPage->pDbPage, iFreePage, isCommit);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  pDbPage->pgno = iFreePage;
+
+  /* If pDbPage was a btree-page, then it may have child pages and/or cells
+  ** that point to overflow pages. The pointer map entries for all these
+  ** pages need to be changed.
+  **
+  ** If pDbPage is an overflow page, then the first 4 bytes may store a
+  ** pointer to a subsequent overflow page. If this is the case, then
+  ** the pointer map needs to be updated for the subsequent overflow page.
+  */
+  if( eType==PTRMAP_BTREE || eType==PTRMAP_ROOTPAGE ){
+    rc = setChildPtrmaps(pDbPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+  }else{
+    Pgno nextOvfl = get4byte(pDbPage->aData);
+    if( nextOvfl!=0 ){
+      ptrmapPut(pBt, nextOvfl, PTRMAP_OVERFLOW2, iFreePage, &rc);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }
+  }
+
+  /* Fix the database pointer on page iPtrPage that pointed at iDbPage so
+  ** that it points at iFreePage. Also fix the pointer map entry for
+  ** iPtrPage.
+  */
+  if( eType!=PTRMAP_ROOTPAGE ){
+    rc = btreeGetPage(pBt, iPtrPage, &pPtrPage, 0);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    rc = sqlite3PagerWrite(pPtrPage->pDbPage);
+    if( rc!=SQLITE_OK ){
+      releasePage(pPtrPage);
+      return rc;
+    }
+    rc = modifyPagePointer(pPtrPage, iDbPage, iFreePage, eType);
+    releasePage(pPtrPage);
+    if( rc==SQLITE_OK ){
+      ptrmapPut(pBt, iFreePage, eType, iPtrPage, &rc);
+    }
+  }
+  return rc;
+}
+
+/* Forward declaration required by incrVacuumStep(). */
+static int allocateBtreePage(BtShared *, MemPage **, Pgno *, Pgno, u8);
+
+/*
+** Perform a single step of an incremental-vacuum. If successful, return
+** SQLITE_OK. If there is no work to do (and therefore no point in
+** calling this function again), return SQLITE_DONE. Or, if an error
+** occurs, return some other error code.
+**
+** More specifically, this function attempts to re-organize the database so
+** that the last page of the file currently in use is no longer in use.
+**
+** Parameter nFin is the number of pages that this database would contain
+** were this function called until it returns SQLITE_DONE.
+**
+** If the bCommit parameter is non-zero, this function assumes that the
+** caller will keep calling incrVacuumStep() until it returns SQLITE_DONE
+** or an error. bCommit is passed true for an auto-vacuum-on-commit
+** operation, or false for an incremental vacuum.
+*/
+static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg, int bCommit){
+  Pgno nFreeList;           /* Number of pages still on the free-list */
+  int rc;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( iLastPg>nFin );
+
+  if( !PTRMAP_ISPAGE(pBt, iLastPg) && iLastPg!=PENDING_BYTE_PAGE(pBt) ){
+    u8 eType;
+    Pgno iPtrPage;
+
+    nFreeList = get4byte(&pBt->pPage1->aData[36]);
+    if( nFreeList==0 ){
+      return SQLITE_DONE;
+    }
+
+    rc = ptrmapGet(pBt, iLastPg, &eType, &iPtrPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( eType==PTRMAP_ROOTPAGE ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+
+    if( eType==PTRMAP_FREEPAGE ){
+      if( bCommit==0 ){
+        /* Remove the page from the files free-list. This is not required
+        ** if bCommit is non-zero. In that case, the free-list will be
+        ** truncated to zero after this function returns, so it doesn't
+        ** matter if it still contains some garbage entries.
+        */
+        Pgno iFreePg;
+        MemPage *pFreePg;
+        rc = allocateBtreePage(pBt, &pFreePg, &iFreePg, iLastPg, BTALLOC_EXACT);
+        if( rc!=SQLITE_OK ){
+          return rc;
+        }
+        assert( iFreePg==iLastPg );
+        releasePage(pFreePg);
+      }
+    } else {
+      Pgno iFreePg;             /* Index of free page to move pLastPg to */
+      MemPage *pLastPg;
+      u8 eMode = BTALLOC_ANY;   /* Mode parameter for allocateBtreePage() */
+      Pgno iNear = 0;           /* nearby parameter for allocateBtreePage() */
+
+      rc = btreeGetPage(pBt, iLastPg, &pLastPg, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+
+      /* If bCommit is zero, this loop runs exactly once and page pLastPg
+      ** is swapped with the first free page pulled off the free list.
+      **
+      ** On the other hand, if bCommit is greater than zero, then keep
+      ** looping until a free-page located within the first nFin pages
+      ** of the file is found.
+      */
+      if( bCommit==0 ){
+        eMode = BTALLOC_LE;
+        iNear = nFin;
+      }
+      do {
+        MemPage *pFreePg;
+        Pgno dbSize = btreePagecount(pBt);
+        rc = allocateBtreePage(pBt, &pFreePg, &iFreePg, iNear, eMode);
+        if( rc!=SQLITE_OK ){
+          releasePage(pLastPg);
+          return rc;
+        }
+        releasePage(pFreePg);
+        if( iFreePg>dbSize ){
+          releasePage(pLastPg);
+          return SQLITE_CORRUPT_BKPT;
+        }
+      }while( bCommit && iFreePg>nFin );
+      assert( iFreePg<iLastPg );
+
+      rc = relocatePage(pBt, pLastPg, eType, iPtrPage, iFreePg, bCommit);
+      releasePage(pLastPg);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }
+  }
+
+  if( bCommit==0 ){
+    do {
+      iLastPg--;
+    }while( iLastPg==PENDING_BYTE_PAGE(pBt) || PTRMAP_ISPAGE(pBt, iLastPg) );
+    pBt->bDoTruncate = 1;
+    pBt->nPage = iLastPg;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The database opened by the first argument is an auto-vacuum database
+** nOrig pages in size containing nFree free pages. Return the expected
+** size of the database in pages following an auto-vacuum operation.
+*/
+static Pgno finalDbSize(BtShared *pBt, Pgno nOrig, Pgno nFree){
+  int nEntry;                     /* Number of entries on one ptrmap page */
+  Pgno nPtrmap;                   /* Number of PtrMap pages to be freed */
+  Pgno nFin;                      /* Return value */
+
+  nEntry = pBt->usableSize/5;
+  nPtrmap = (nFree-nOrig+PTRMAP_PAGENO(pBt, nOrig)+nEntry)/nEntry;
+  nFin = nOrig - nFree - nPtrmap;
+  if( nOrig>PENDING_BYTE_PAGE(pBt) && nFin<PENDING_BYTE_PAGE(pBt) ){
+    nFin--;
+  }
+  while( PTRMAP_ISPAGE(pBt, nFin) || nFin==PENDING_BYTE_PAGE(pBt) ){
+    nFin--;
+  }
+
+  return nFin;
+}
+
+/*
+** A write-transaction must be opened before calling this function.
+** It performs a single unit of work towards an incremental vacuum.
+**
+** If the incremental vacuum is finished after this function has run,
+** SQLITE_DONE is returned. If it is not finished, but no error occurred,
+** SQLITE_OK is returned. Otherwise an SQLite error code.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *p){
+  int rc;
+  BtShared *pBt = p->pBt;
+
+  sqlite3BtreeEnter(p);
+  assert( pBt->inTransaction==TRANS_WRITE && p->inTrans==TRANS_WRITE );
+  if( !pBt->autoVacuum ){
+    rc = SQLITE_DONE;
+  }else{
+    Pgno nOrig = btreePagecount(pBt);
+    Pgno nFree = get4byte(&pBt->pPage1->aData[36]);
+    Pgno nFin = finalDbSize(pBt, nOrig, nFree);
+
+    if( nOrig<nFin || nFree>=nOrig ){
+      rc = SQLITE_CORRUPT_BKPT;
+    }else if( nFree>0 ){
+      rc = saveAllCursors(pBt, 0, 0);
+      if( rc==SQLITE_OK ){
+        invalidateAllOverflowCache(pBt);
+        rc = incrVacuumStep(pBt, nFin, nOrig, 0);
+      }
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+        put4byte(&pBt->pPage1->aData[28], pBt->nPage);
+      }
+    }else{
+      rc = SQLITE_DONE;
+    }
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** This routine is called prior to sqlite3PagerCommit when a transaction
+** is committed for an auto-vacuum database.
+*/
+static int autoVacuumCommit(Btree *p){
+  int rc = SQLITE_OK;
+  Pager *pPager;
+  BtShared *pBt;
+  sqlite3 *db;
+  VVA_ONLY( int nRef );
+
+  assert( p!=0 );
+  pBt = p->pBt;
+  pPager = pBt->pPager;
+  VVA_ONLY( nRef = sqlite3PagerRefcount(pPager); )
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  invalidateAllOverflowCache(pBt);
+  assert(pBt->autoVacuum);
+  if( !pBt->incrVacuum ){
+    Pgno nFin;         /* Number of pages in database after autovacuuming */
+    Pgno nFree;        /* Number of pages on the freelist initially */
+    Pgno nVac;         /* Number of pages to vacuum */
+    Pgno iFree;        /* The next page to be freed */
+    Pgno nOrig;        /* Database size before freeing */
+
+    nOrig = btreePagecount(pBt);
+    if( PTRMAP_ISPAGE(pBt, nOrig) || nOrig==PENDING_BYTE_PAGE(pBt) ){
+      /* It is not possible to create a database for which the final page
+      ** is either a pointer-map page or the pending-byte page. If one
+      ** is encountered, this indicates corruption.
+      */
+      return SQLITE_CORRUPT_BKPT;
+    }
+
+    nFree = get4byte(&pBt->pPage1->aData[36]);
+    db = p->db;
+    if( db->xAutovacPages ){
+      int iDb;
+      for(iDb=0; ALWAYS(iDb<db->nDb); iDb++){
+        if( db->aDb[iDb].pBt==p ) break;
+      }
+      nVac = db->xAutovacPages(
+        db->pAutovacPagesArg,
+        db->aDb[iDb].zDbSName,
+        nOrig,
+        nFree,
+        pBt->pageSize
+      );
+      if( nVac>nFree ){
+        nVac = nFree;
+      }
+      if( nVac==0 ){
+        return SQLITE_OK;
+      }
+    }else{
+      nVac = nFree;
+    }
+    nFin = finalDbSize(pBt, nOrig, nVac);
+    if( nFin>nOrig ) return SQLITE_CORRUPT_BKPT;
+    if( nFin<nOrig ){
+      rc = saveAllCursors(pBt, 0, 0);
+    }
+    for(iFree=nOrig; iFree>nFin && rc==SQLITE_OK; iFree--){
+      rc = incrVacuumStep(pBt, nFin, iFree, nVac==nFree);
+    }
+    if( (rc==SQLITE_DONE || rc==SQLITE_OK) && nFree>0 ){
+      rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+      if( nVac==nFree ){
+        put4byte(&pBt->pPage1->aData[32], 0);
+        put4byte(&pBt->pPage1->aData[36], 0);
+      }
+      put4byte(&pBt->pPage1->aData[28], nFin);
+      pBt->bDoTruncate = 1;
+      pBt->nPage = nFin;
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3PagerRollback(pPager);
+    }
+  }
+
+  assert( nRef>=sqlite3PagerRefcount(pPager) );
+  return rc;
+}
+
+#else /* ifndef SQLITE_OMIT_AUTOVACUUM */
+# define setChildPtrmaps(x) SQLITE_OK
+#endif
+
+/*
+** This routine does the first phase of a two-phase commit.  This routine
+** causes a rollback journal to be created (if it does not already exist)
+** and populated with enough information so that if a power loss occurs
+** the database can be restored to its original state by playing back
+** the journal.  Then the contents of the journal are flushed out to
+** the disk.  After the journal is safely on oxide, the changes to the
+** database are written into the database file and flushed to oxide.
+** At the end of this call, the rollback journal still exists on the
+** disk and we are still holding all locks, so the transaction has not
+** committed.  See sqlite3BtreeCommitPhaseTwo() for the second phase of the
+** commit process.
+**
+** This call is a no-op if no write-transaction is currently active on pBt.
+**
+** Otherwise, sync the database file for the btree pBt. zSuperJrnl points to
+** the name of a super-journal file that should be written into the
+** individual journal file, or is NULL, indicating no super-journal file
+** (single database transaction).
+**
+** When this is called, the super-journal should already have been
+** created, populated with this journal pointer and synced to disk.
+**
+** Once this is routine has returned, the only thing required to commit
+** the write-transaction for this database file is to delete the journal.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseOne(Btree *p, const char *zSuperJrnl){
+  int rc = SQLITE_OK;
+  if( p->inTrans==TRANS_WRITE ){
+    BtShared *pBt = p->pBt;
+    sqlite3BtreeEnter(p);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum ){
+      rc = autoVacuumCommit(p);
+      if( rc!=SQLITE_OK ){
+        sqlite3BtreeLeave(p);
+        return rc;
+      }
+    }
+    if( pBt->bDoTruncate ){
+      sqlite3PagerTruncateImage(pBt->pPager, pBt->nPage);
+    }
+#endif
+    rc = sqlite3PagerCommitPhaseOne(pBt->pPager, zSuperJrnl, 0);
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+
+/*
+** This function is called from both BtreeCommitPhaseTwo() and BtreeRollback()
+** at the conclusion of a transaction.
+*/
+static void btreeEndTransaction(Btree *p){
+  BtShared *pBt = p->pBt;
+  sqlite3 *db = p->db;
+  assert( sqlite3BtreeHoldsMutex(p) );
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  pBt->bDoTruncate = 0;
+#endif
+  if( p->inTrans>TRANS_NONE && db->nVdbeRead>1 ){
+    /* If there are other active statements that belong to this database
+    ** handle, downgrade to a read-only transaction. The other statements
+    ** may still be reading from the database.  */
+    downgradeAllSharedCacheTableLocks(p);
+    p->inTrans = TRANS_READ;
+  }else{
+    /* If the handle had any kind of transaction open, decrement the
+    ** transaction count of the shared btree. If the transaction count
+    ** reaches 0, set the shared state to TRANS_NONE. The unlockBtreeIfUnused()
+    ** call below will unlock the pager.  */
+    if( p->inTrans!=TRANS_NONE ){
+      clearAllSharedCacheTableLocks(p);
+      pBt->nTransaction--;
+      if( 0==pBt->nTransaction ){
+        pBt->inTransaction = TRANS_NONE;
+      }
+    }
+
+    /* Set the current transaction state to TRANS_NONE and unlock the
+    ** pager if this call closed the only read or write transaction.  */
+    p->inTrans = TRANS_NONE;
+    unlockBtreeIfUnused(pBt);
+  }
+
+  btreeIntegrity(p);
+}
+
+/*
+** Commit the transaction currently in progress.
+**
+** This routine implements the second phase of a 2-phase commit.  The
+** sqlite3BtreeCommitPhaseOne() routine does the first phase and should
+** be invoked prior to calling this routine.  The sqlite3BtreeCommitPhaseOne()
+** routine did all the work of writing information out to disk and flushing the
+** contents so that they are written onto the disk platter.  All this
+** routine has to do is delete or truncate or zero the header in the
+** the rollback journal (which causes the transaction to commit) and
+** drop locks.
+**
+** Normally, if an error occurs while the pager layer is attempting to
+** finalize the underlying journal file, this function returns an error and
+** the upper layer will attempt a rollback. However, if the second argument
+** is non-zero then this b-tree transaction is part of a multi-file
+** transaction. In this case, the transaction has already been committed
+** (by deleting a super-journal file) and the caller will ignore this
+** functions return code. So, even if an error occurs in the pager layer,
+** reset the b-tree objects internal state to indicate that the write
+** transaction has been closed. This is quite safe, as the pager will have
+** transitioned to the error state.
+**
+** This will release the write lock on the database file.  If there
+** are no active cursors, it also releases the read lock.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree *p, int bCleanup){
+
+  if( p->inTrans==TRANS_NONE ) return SQLITE_OK;
+  sqlite3BtreeEnter(p);
+  btreeIntegrity(p);
+
+  /* If the handle has a write-transaction open, commit the shared-btrees
+  ** transaction and set the shared state to TRANS_READ.
+  */
+  if( p->inTrans==TRANS_WRITE ){
+    int rc;
+    BtShared *pBt = p->pBt;
+    assert( pBt->inTransaction==TRANS_WRITE );
+    assert( pBt->nTransaction>0 );
+    rc = sqlite3PagerCommitPhaseTwo(pBt->pPager);
+    if( rc!=SQLITE_OK && bCleanup==0 ){
+      sqlite3BtreeLeave(p);
+      return rc;
+    }
+    p->iBDataVersion--;  /* Compensate for pPager->iDataVersion++; */
+    pBt->inTransaction = TRANS_READ;
+    btreeClearHasContent(pBt);
+  }
+
+  btreeEndTransaction(p);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+
+/*
+** Do both phases of a commit.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCommit(Btree *p){
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = sqlite3BtreeCommitPhaseOne(p, 0);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3BtreeCommitPhaseTwo(p, 0);
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** This routine sets the state to CURSOR_FAULT and the error
+** code to errCode for every cursor on any BtShared that pBtree
+** references.  Or if the writeOnly flag is set to 1, then only
+** trip write cursors and leave read cursors unchanged.
+**
+** Every cursor is a candidate to be tripped, including cursors
+** that belong to other database connections that happen to be
+** sharing the cache with pBtree.
+**
+** This routine gets called when a rollback occurs. If the writeOnly
+** flag is true, then only write-cursors need be tripped - read-only
+** cursors save their current positions so that they may continue
+** following the rollback. Or, if writeOnly is false, all cursors are
+** tripped. In general, writeOnly is false if the transaction being
+** rolled back modified the database schema. In this case b-tree root
+** pages may be moved or deleted from the database altogether, making
+** it unsafe for read cursors to continue.
+**
+** If the writeOnly flag is true and an error is encountered while
+** saving the current position of a read-only cursor, all cursors,
+** including all read-cursors are tripped.
+**
+** SQLITE_OK is returned if successful, or if an error occurs while
+** saving a cursor position, an SQLite error code.
+*/
+SQLITE_PRIVATE int sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode, int writeOnly){
+  BtCursor *p;
+  int rc = SQLITE_OK;
+
+  assert( (writeOnly==0 || writeOnly==1) && BTCF_WriteFlag==1 );
+  if( pBtree ){
+    sqlite3BtreeEnter(pBtree);
+    for(p=pBtree->pBt->pCursor; p; p=p->pNext){
+      if( writeOnly && (p->curFlags & BTCF_WriteFlag)==0 ){
+        if( p->eState==CURSOR_VALID || p->eState==CURSOR_SKIPNEXT ){
+          rc = saveCursorPosition(p);
+          if( rc!=SQLITE_OK ){
+            (void)sqlite3BtreeTripAllCursors(pBtree, rc, 0);
+            break;
+          }
+        }
+      }else{
+        sqlite3BtreeClearCursor(p);
+        p->eState = CURSOR_FAULT;
+        p->skipNext = errCode;
+      }
+      btreeReleaseAllCursorPages(p);
+    }
+    sqlite3BtreeLeave(pBtree);
+  }
+  return rc;
+}
+
+/*
+** Set the pBt->nPage field correctly, according to the current
+** state of the database.  Assume pBt->pPage1 is valid.
+*/
+static void btreeSetNPage(BtShared *pBt, MemPage *pPage1){
+  int nPage = get4byte(&pPage1->aData[28]);
+  testcase( nPage==0 );
+  if( nPage==0 ) sqlite3PagerPagecount(pBt->pPager, &nPage);
+  testcase( pBt->nPage!=(u32)nPage );
+  pBt->nPage = nPage;
+}
+
+/*
+** Rollback the transaction in progress.
+**
+** If tripCode is not SQLITE_OK then cursors will be invalidated (tripped).
+** Only write cursors are tripped if writeOnly is true but all cursors are
+** tripped if writeOnly is false.  Any attempt to use
+** a tripped cursor will result in an error.
+**
+** This will release the write lock on the database file.  If there
+** are no active cursors, it also releases the read lock.
+*/
+SQLITE_PRIVATE int sqlite3BtreeRollback(Btree *p, int tripCode, int writeOnly){
+  int rc;
+  BtShared *pBt = p->pBt;
+  MemPage *pPage1;
+
+  assert( writeOnly==1 || writeOnly==0 );
+  assert( tripCode==SQLITE_ABORT_ROLLBACK || tripCode==SQLITE_OK );
+  sqlite3BtreeEnter(p);
+  if( tripCode==SQLITE_OK ){
+    rc = tripCode = saveAllCursors(pBt, 0, 0);
+    if( rc ) writeOnly = 0;
+  }else{
+    rc = SQLITE_OK;
+  }
+  if( tripCode ){
+    int rc2 = sqlite3BtreeTripAllCursors(p, tripCode, writeOnly);
+    assert( rc==SQLITE_OK || (writeOnly==0 && rc2==SQLITE_OK) );
+    if( rc2!=SQLITE_OK ) rc = rc2;
+  }
+  btreeIntegrity(p);
+
+  if( p->inTrans==TRANS_WRITE ){
+    int rc2;
+
+    assert( TRANS_WRITE==pBt->inTransaction );
+    rc2 = sqlite3PagerRollback(pBt->pPager);
+    if( rc2!=SQLITE_OK ){
+      rc = rc2;
+    }
+
+    /* The rollback may have destroyed the pPage1->aData value.  So
+    ** call btreeGetPage() on page 1 again to make
+    ** sure pPage1->aData is set correctly. */
+    if( btreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){
+      btreeSetNPage(pBt, pPage1);
+      releasePageOne(pPage1);
+    }
+    assert( countValidCursors(pBt, 1)==0 );
+    pBt->inTransaction = TRANS_READ;
+    btreeClearHasContent(pBt);
+  }
+
+  btreeEndTransaction(p);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Start a statement subtransaction. The subtransaction can be rolled
+** back independently of the main transaction. You must start a transaction
+** before starting a subtransaction. The subtransaction is ended automatically
+** if the main transaction commits or rolls back.
+**
+** Statement subtransactions are used around individual SQL statements
+** that are contained within a BEGIN...COMMIT block.  If a constraint
+** error occurs within the statement, the effect of that one statement
+** can be rolled back without having to rollback the entire transaction.
+**
+** A statement sub-transaction is implemented as an anonymous savepoint. The
+** value passed as the second parameter is the total number of savepoints,
+** including the new anonymous savepoint, open on the B-Tree. i.e. if there
+** are no active savepoints and no other statement-transactions open,
+** iStatement is 1. This anonymous savepoint can be released or rolled back
+** using the sqlite3BtreeSavepoint() function.
+*/
+SQLITE_PRIVATE int sqlite3BtreeBeginStmt(Btree *p, int iStatement){
+  int rc;
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans==TRANS_WRITE );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
+  assert( iStatement>0 );
+  assert( iStatement>p->db->nSavepoint );
+  assert( pBt->inTransaction==TRANS_WRITE );
+  /* At the pager level, a statement transaction is a savepoint with
+  ** an index greater than all savepoints created explicitly using
+  ** SQL statements. It is illegal to open, release or rollback any
+  ** such savepoints while the statement transaction savepoint is active.
+  */
+  rc = sqlite3PagerOpenSavepoint(pBt->pPager, iStatement);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** The second argument to this function, op, is always SAVEPOINT_ROLLBACK
+** or SAVEPOINT_RELEASE. This function either releases or rolls back the
+** savepoint identified by parameter iSavepoint, depending on the value
+** of op.
+**
+** Normally, iSavepoint is greater than or equal to zero. However, if op is
+** SAVEPOINT_ROLLBACK, then iSavepoint may also be -1. In this case the
+** contents of the entire transaction are rolled back. This is different
+** from a normal transaction rollback, as no locks are released and the
+** transaction remains open.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
+  int rc = SQLITE_OK;
+  if( p && p->inTrans==TRANS_WRITE ){
+    BtShared *pBt = p->pBt;
+    assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
+    assert( iSavepoint>=0 || (iSavepoint==-1 && op==SAVEPOINT_ROLLBACK) );
+    sqlite3BtreeEnter(p);
+    if( op==SAVEPOINT_ROLLBACK ){
+      rc = saveAllCursors(pBt, 0, 0);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3PagerSavepoint(pBt->pPager, op, iSavepoint);
+    }
+    if( rc==SQLITE_OK ){
+      if( iSavepoint<0 && (pBt->btsFlags & BTS_INITIALLY_EMPTY)!=0 ){
+        pBt->nPage = 0;
+      }
+      rc = newDatabase(pBt);
+      btreeSetNPage(pBt, pBt->pPage1);
+
+      /* pBt->nPage might be zero if the database was corrupt when
+      ** the transaction was started. Otherwise, it must be at least 1.  */
+      assert( CORRUPT_DB || pBt->nPage>0 );
+    }
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+
+/*
+** Create a new cursor for the BTree whose root is on the page
+** iTable. If a read-only cursor is requested, it is assumed that
+** the caller already has at least a read-only transaction open
+** on the database already. If a write-cursor is requested, then
+** the caller is assumed to have an open write transaction.
+**
+** If the BTREE_WRCSR bit of wrFlag is clear, then the cursor can only
+** be used for reading.  If the BTREE_WRCSR bit is set, then the cursor
+** can be used for reading or for writing if other conditions for writing
+** are also met.  These are the conditions that must be met in order
+** for writing to be allowed:
+**
+** 1:  The cursor must have been opened with wrFlag containing BTREE_WRCSR
+**
+** 2:  Other database connections that share the same pager cache
+**     but which are not in the READ_UNCOMMITTED state may not have
+**     cursors open with wrFlag==0 on the same table.  Otherwise
+**     the changes made by this write cursor would be visible to
+**     the read cursors in the other database connection.
+**
+** 3:  The database must be writable (not on read-only media)
+**
+** 4:  There must be an active transaction.
+**
+** The BTREE_FORDELETE bit of wrFlag may optionally be set if BTREE_WRCSR
+** is set.  If FORDELETE is set, that is a hint to the implementation that
+** this cursor will only be used to seek to and delete entries of an index
+** as part of a larger DELETE statement.  The FORDELETE hint is not used by
+** this implementation.  But in a hypothetical alternative storage engine
+** in which index entries are automatically deleted when corresponding table
+** rows are deleted, the FORDELETE flag is a hint that all SEEK and DELETE
+** operations on this cursor can be no-ops and all READ operations can
+** return a null row (2-bytes: 0x01 0x00).
+**
+** No checking is done to make sure that page iTable really is the
+** root page of a b-tree.  If it is not, then the cursor acquired
+** will not work correctly.
+**
+** It is assumed that the sqlite3BtreeCursorZero() has been called
+** on pCur to initialize the memory space prior to invoking this routine.
+*/
+static int btreeCursor(
+  Btree *p,                              /* The btree */
+  Pgno iTable,                           /* Root page of table to open */
+  int wrFlag,                            /* 1 to write. 0 read-only */
+  struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
+  BtCursor *pCur                         /* Space for new cursor */
+){
+  BtShared *pBt = p->pBt;                /* Shared b-tree handle */
+  BtCursor *pX;                          /* Looping over other all cursors */
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( wrFlag==0
+       || wrFlag==BTREE_WRCSR
+       || wrFlag==(BTREE_WRCSR|BTREE_FORDELETE)
+  );
+
+  /* The following assert statements verify that if this is a sharable
+  ** b-tree database, the connection is holding the required table locks,
+  ** and that no other connection has any open cursor that conflicts with
+  ** this lock.  The iTable<1 term disables the check for corrupt schemas. */
+  assert( hasSharedCacheTableLock(p, iTable, pKeyInfo!=0, (wrFlag?2:1))
+          || iTable<1 );
+  assert( wrFlag==0 || !hasReadConflicts(p, iTable) );
+
+  /* Assert that the caller has opened the required transaction. */
+  assert( p->inTrans>TRANS_NONE );
+  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
+  assert( pBt->pPage1 && pBt->pPage1->aData );
+  assert( wrFlag==0 || (pBt->btsFlags & BTS_READ_ONLY)==0 );
+
+  if( iTable<=1 ){
+    if( iTable<1 ){
+      return SQLITE_CORRUPT_BKPT;
+    }else if( btreePagecount(pBt)==0 ){
+      assert( wrFlag==0 );
+      iTable = 0;
+    }
+  }
+
+  /* Now that no other errors can occur, finish filling in the BtCursor
+  ** variables and link the cursor into the BtShared list.  */
+  pCur->pgnoRoot = iTable;
+  pCur->iPage = -1;
+  pCur->pKeyInfo = pKeyInfo;
+  pCur->pBtree = p;
+  pCur->pBt = pBt;
+  pCur->curFlags = 0;
+  /* If there are two or more cursors on the same btree, then all such
+  ** cursors *must* have the BTCF_Multiple flag set. */
+  for(pX=pBt->pCursor; pX; pX=pX->pNext){
+    if( pX->pgnoRoot==iTable ){
+      pX->curFlags |= BTCF_Multiple;
+      pCur->curFlags = BTCF_Multiple;
+    }
+  }
+  pCur->eState = CURSOR_INVALID;
+  pCur->pNext = pBt->pCursor;
+  pBt->pCursor = pCur;
+  if( wrFlag ){
+    pCur->curFlags |= BTCF_WriteFlag;
+    pCur->curPagerFlags = 0;
+    if( pBt->pTmpSpace==0 ) return allocateTempSpace(pBt);
+  }else{
+    pCur->curPagerFlags = PAGER_GET_READONLY;
+  }
+  return SQLITE_OK;
+}
+static int btreeCursorWithLock(
+  Btree *p,                              /* The btree */
+  Pgno iTable,                           /* Root page of table to open */
+  int wrFlag,                            /* 1 to write. 0 read-only */
+  struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
+  BtCursor *pCur                         /* Space for new cursor */
+){
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeCursor(
+  Btree *p,                                   /* The btree */
+  Pgno iTable,                                /* Root page of table to open */
+  int wrFlag,                                 /* 1 to write. 0 read-only */
+  struct KeyInfo *pKeyInfo,                   /* First arg to xCompare() */
+  BtCursor *pCur                              /* Write new cursor here */
+){
+  if( p->sharable ){
+    return btreeCursorWithLock(p, iTable, wrFlag, pKeyInfo, pCur);
+  }else{
+    return btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
+  }
+}
+
+/*
+** Return the size of a BtCursor object in bytes.
+**
+** This interfaces is needed so that users of cursors can preallocate
+** sufficient storage to hold a cursor.  The BtCursor object is opaque
+** to users so they cannot do the sizeof() themselves - they must call
+** this routine.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorSize(void){
+  return ROUND8(sizeof(BtCursor));
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Return true if and only if the Btree object will be automatically
+** closed with the BtCursor closes.  This is used within assert() statements
+** only.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClosesWithCursor(
+  Btree *pBtree,       /* the btree object */
+  BtCursor *pCur       /* Corresponding cursor */
+){
+  BtShared *pBt = pBtree->pBt;
+  if( (pBt->openFlags & BTREE_SINGLE)==0 ) return 0;
+  if( pBt->pCursor!=pCur ) return 0;
+  if( pCur->pNext!=0 ) return 0;
+  if( pCur->pBtree!=pBtree ) return 0;
+  return 1;
+}
+#endif
+
+/*
+** Initialize memory that will be converted into a BtCursor object.
+**
+** The simple approach here would be to memset() the entire object
+** to zero.  But it turns out that the apPage[] and aiIdx[] arrays
+** do not need to be zeroed and they are large, so we can save a lot
+** of run-time by skipping the initialization of those elements.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor *p){
+  memset(p, 0, offsetof(BtCursor, BTCURSOR_FIRST_UNINIT));
+}
+
+/*
+** Close a cursor.  The read lock on the database file is released
+** when the last cursor is closed.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor *pCur){
+  Btree *pBtree = pCur->pBtree;
+  if( pBtree ){
+    BtShared *pBt = pCur->pBt;
+    sqlite3BtreeEnter(pBtree);
+    assert( pBt->pCursor!=0 );
+    if( pBt->pCursor==pCur ){
+      pBt->pCursor = pCur->pNext;
+    }else{
+      BtCursor *pPrev = pBt->pCursor;
+      do{
+        if( pPrev->pNext==pCur ){
+          pPrev->pNext = pCur->pNext;
+          break;
+        }
+        pPrev = pPrev->pNext;
+      }while( ALWAYS(pPrev) );
+    }
+    btreeReleaseAllCursorPages(pCur);
+    unlockBtreeIfUnused(pBt);
+    sqlite3_free(pCur->aOverflow);
+    sqlite3_free(pCur->pKey);
+    if( (pBt->openFlags & BTREE_SINGLE) && pBt->pCursor==0 ){
+      /* Since the BtShared is not sharable, there is no need to
+      ** worry about the missing sqlite3BtreeLeave() call here.  */
+      assert( pBtree->sharable==0 );
+      sqlite3BtreeClose(pBtree);
+    }else{
+      sqlite3BtreeLeave(pBtree);
+    }
+    pCur->pBtree = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Make sure the BtCursor* given in the argument has a valid
+** BtCursor.info structure.  If it is not already valid, call
+** btreeParseCell() to fill it in.
+**
+** BtCursor.info is a cache of the information in the current cell.
+** Using this cache reduces the number of calls to btreeParseCell().
+*/
+#ifndef NDEBUG
+  static int cellInfoEqual(CellInfo *a, CellInfo *b){
+    if( a->nKey!=b->nKey ) return 0;
+    if( a->pPayload!=b->pPayload ) return 0;
+    if( a->nPayload!=b->nPayload ) return 0;
+    if( a->nLocal!=b->nLocal ) return 0;
+    if( a->nSize!=b->nSize ) return 0;
+    return 1;
+  }
+  static void assertCellInfo(BtCursor *pCur){
+    CellInfo info;
+    memset(&info, 0, sizeof(info));
+    btreeParseCell(pCur->pPage, pCur->ix, &info);
+    assert( CORRUPT_DB || cellInfoEqual(&info, &pCur->info) );
+  }
+#else
+  #define assertCellInfo(x)
+#endif
+static SQLITE_NOINLINE void getCellInfo(BtCursor *pCur){
+  if( pCur->info.nSize==0 ){
+    pCur->curFlags |= BTCF_ValidNKey;
+    btreeParseCell(pCur->pPage,pCur->ix,&pCur->info);
+  }else{
+    assertCellInfo(pCur);
+  }
+}
+
+#ifndef NDEBUG  /* The next routine used only within assert() statements */
+/*
+** Return true if the given BtCursor is valid.  A valid cursor is one
+** that is currently pointing to a row in a (non-empty) table.
+** This is a verification routine is used only within assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValid(BtCursor *pCur){
+  return pCur && pCur->eState==CURSOR_VALID;
+}
+#endif /* NDEBUG */
+SQLITE_PRIVATE int sqlite3BtreeCursorIsValidNN(BtCursor *pCur){
+  assert( pCur!=0 );
+  return pCur->eState==CURSOR_VALID;
+}
+
+/*
+** Return the value of the integer key or "rowid" for a table btree.
+** This routine is only valid for a cursor that is pointing into a
+** ordinary table btree.  If the cursor points to an index btree or
+** is invalid, the result of this routine is undefined.
+*/
+SQLITE_PRIVATE i64 sqlite3BtreeIntegerKey(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->curIntKey );
+  getCellInfo(pCur);
+  return pCur->info.nKey;
+}
+
+/*
+** Pin or unpin a cursor.
+*/
+SQLITE_PRIVATE void sqlite3BtreeCursorPin(BtCursor *pCur){
+  assert( (pCur->curFlags & BTCF_Pinned)==0 );
+  pCur->curFlags |= BTCF_Pinned;
+}
+SQLITE_PRIVATE void sqlite3BtreeCursorUnpin(BtCursor *pCur){
+  assert( (pCur->curFlags & BTCF_Pinned)!=0 );
+  pCur->curFlags &= ~BTCF_Pinned;
+}
+
+/*
+** Return the offset into the database file for the start of the
+** payload to which the cursor is pointing.
+*/
+SQLITE_PRIVATE i64 sqlite3BtreeOffset(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  getCellInfo(pCur);
+  return (i64)pCur->pBt->pageSize*((i64)pCur->pPage->pgno - 1) +
+         (i64)(pCur->info.pPayload - pCur->pPage->aData);
+}
+
+/*
+** Return the number of bytes of payload for the entry that pCur is
+** currently pointing to.  For table btrees, this will be the amount
+** of data.  For index btrees, this will be the size of the key.
+**
+** The caller must guarantee that the cursor is pointing to a non-NULL
+** valid entry.  In other words, the calling procedure must guarantee
+** that the cursor has Cursor.eState==CURSOR_VALID.
+*/
+SQLITE_PRIVATE u32 sqlite3BtreePayloadSize(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  getCellInfo(pCur);
+  return pCur->info.nPayload;
+}
+
+/*
+** Return an upper bound on the size of any record for the table
+** that the cursor is pointing into.
+**
+** This is an optimization.  Everything will still work if this
+** routine always returns 2147483647 (which is the largest record
+** that SQLite can handle) or more.  But returning a smaller value might
+** prevent large memory allocations when trying to interpret a
+** corrupt database.
+**
+** The current implementation merely returns the size of the underlying
+** database file.
+*/
+SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  return pCur->pBt->pageSize * (sqlite3_int64)pCur->pBt->nPage;
+}
+
+/*
+** Given the page number of an overflow page in the database (parameter
+** ovfl), this function finds the page number of the next page in the
+** linked list of overflow pages. If possible, it uses the auto-vacuum
+** pointer-map data instead of reading the content of page ovfl to do so.
+**
+** If an error occurs an SQLite error code is returned. Otherwise:
+**
+** The page number of the next overflow page in the linked list is
+** written to *pPgnoNext. If page ovfl is the last page in its linked
+** list, *pPgnoNext is set to zero.
+**
+** If ppPage is not NULL, and a reference to the MemPage object corresponding
+** to page number pOvfl was obtained, then *ppPage is set to point to that
+** reference. It is the responsibility of the caller to call releasePage()
+** on *ppPage to free the reference. In no reference was obtained (because
+** the pointer-map was used to obtain the value for *pPgnoNext), then
+** *ppPage is set to zero.
+*/
+static int getOverflowPage(
+  BtShared *pBt,               /* The database file */
+  Pgno ovfl,                   /* Current overflow page number */
+  MemPage **ppPage,            /* OUT: MemPage handle (may be NULL) */
+  Pgno *pPgnoNext              /* OUT: Next overflow page number */
+){
+  Pgno next = 0;
+  MemPage *pPage = 0;
+  int rc = SQLITE_OK;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert(pPgnoNext);
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  /* Try to find the next page in the overflow list using the
+  ** autovacuum pointer-map pages. Guess that the next page in
+  ** the overflow list is page number (ovfl+1). If that guess turns
+  ** out to be wrong, fall back to loading the data of page
+  ** number ovfl to determine the next page number.
+  */
+  if( pBt->autoVacuum ){
+    Pgno pgno;
+    Pgno iGuess = ovfl+1;
+    u8 eType;
+
+    while( PTRMAP_ISPAGE(pBt, iGuess) || iGuess==PENDING_BYTE_PAGE(pBt) ){
+      iGuess++;
+    }
+
+    if( iGuess<=btreePagecount(pBt) ){
+      rc = ptrmapGet(pBt, iGuess, &eType, &pgno);
+      if( rc==SQLITE_OK && eType==PTRMAP_OVERFLOW2 && pgno==ovfl ){
+        next = iGuess;
+        rc = SQLITE_DONE;
+      }
+    }
+  }
+#endif
+
+  assert( next==0 || rc==SQLITE_DONE );
+  if( rc==SQLITE_OK ){
+    rc = btreeGetPage(pBt, ovfl, &pPage, (ppPage==0) ? PAGER_GET_READONLY : 0);
+    assert( rc==SQLITE_OK || pPage==0 );
+    if( rc==SQLITE_OK ){
+      next = get4byte(pPage->aData);
+    }
+  }
+
+  *pPgnoNext = next;
+  if( ppPage ){
+    *ppPage = pPage;
+  }else{
+    releasePage(pPage);
+  }
+  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
+}
+
+/*
+** Copy data from a buffer to a page, or from a page to a buffer.
+**
+** pPayload is a pointer to data stored on database page pDbPage.
+** If argument eOp is false, then nByte bytes of data are copied
+** from pPayload to the buffer pointed at by pBuf. If eOp is true,
+** then sqlite3PagerWrite() is called on pDbPage and nByte bytes
+** of data are copied from the buffer pBuf to pPayload.
+**
+** SQLITE_OK is returned on success, otherwise an error code.
+*/
+static int copyPayload(
+  void *pPayload,           /* Pointer to page data */
+  void *pBuf,               /* Pointer to buffer */
+  int nByte,                /* Number of bytes to copy */
+  int eOp,                  /* 0 -> copy from page, 1 -> copy to page */
+  DbPage *pDbPage           /* Page containing pPayload */
+){
+  if( eOp ){
+    /* Copy data from buffer to page (a write operation) */
+    int rc = sqlite3PagerWrite(pDbPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    memcpy(pPayload, pBuf, nByte);
+  }else{
+    /* Copy data from page to buffer (a read operation) */
+    memcpy(pBuf, pPayload, nByte);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is used to read or overwrite payload information
+** for the entry that the pCur cursor is pointing to. The eOp
+** argument is interpreted as follows:
+**
+**   0: The operation is a read. Populate the overflow cache.
+**   1: The operation is a write. Populate the overflow cache.
+**
+** A total of "amt" bytes are read or written beginning at "offset".
+** Data is read to or from the buffer pBuf.
+**
+** The content being read or written might appear on the main page
+** or be scattered out on multiple overflow pages.
+**
+** If the current cursor entry uses one or more overflow pages
+** this function may allocate space for and lazily populate
+** the overflow page-list cache array (BtCursor.aOverflow).
+** Subsequent calls use this cache to make seeking to the supplied offset
+** more efficient.
+**
+** Once an overflow page-list cache has been allocated, it must be
+** invalidated if some other cursor writes to the same table, or if
+** the cursor is moved to a different row. Additionally, in auto-vacuum
+** mode, the following events may invalidate an overflow page-list cache.
+**
+**   * An incremental vacuum,
+**   * A commit in auto_vacuum="full" mode,
+**   * Creating a table (may require moving an overflow page).
+*/
+static int accessPayload(
+  BtCursor *pCur,      /* Cursor pointing to entry to read from */
+  u32 offset,          /* Begin reading this far into payload */
+  u32 amt,             /* Read this many bytes */
+  unsigned char *pBuf, /* Write the bytes into this buffer */
+  int eOp              /* zero to read. non-zero to write. */
+){
+  unsigned char *aPayload;
+  int rc = SQLITE_OK;
+  int iIdx = 0;
+  MemPage *pPage = pCur->pPage;               /* Btree page of current entry */
+  BtShared *pBt = pCur->pBt;                  /* Btree this cursor belongs to */
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+  unsigned char * const pBufStart = pBuf;     /* Start of original out buffer */
+#endif
+
+  assert( pPage );
+  assert( eOp==0 || eOp==1 );
+  assert( pCur->eState==CURSOR_VALID );
+  if( pCur->ix>=pPage->nCell ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  assert( cursorHoldsMutex(pCur) );
+
+  getCellInfo(pCur);
+  aPayload = pCur->info.pPayload;
+  assert( offset+amt <= pCur->info.nPayload );
+
+  assert( aPayload > pPage->aData );
+  if( (uptr)(aPayload - pPage->aData) > (pBt->usableSize - pCur->info.nLocal) ){
+    /* Trying to read or write past the end of the data is an error.  The
+    ** conditional above is really:
+    **    &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
+    ** but is recast into its current form to avoid integer overflow problems
+    */
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+
+  /* Check if data must be read/written to/from the btree page itself. */
+  if( offset<pCur->info.nLocal ){
+    int a = amt;
+    if( a+offset>pCur->info.nLocal ){
+      a = pCur->info.nLocal - offset;
+    }
+    rc = copyPayload(&aPayload[offset], pBuf, a, eOp, pPage->pDbPage);
+    offset = 0;
+    pBuf += a;
+    amt -= a;
+  }else{
+    offset -= pCur->info.nLocal;
+  }
+
+
+  if( rc==SQLITE_OK && amt>0 ){
+    const u32 ovflSize = pBt->usableSize - 4;  /* Bytes content per ovfl page */
+    Pgno nextPage;
+
+    nextPage = get4byte(&aPayload[pCur->info.nLocal]);
+
+    /* If the BtCursor.aOverflow[] has not been allocated, allocate it now.
+    **
+    ** The aOverflow[] array is sized at one entry for each overflow page
+    ** in the overflow chain. The page number of the first overflow page is
+    ** stored in aOverflow[0], etc. A value of 0 in the aOverflow[] array
+    ** means "not yet known" (the cache is lazily populated).
+    */
+    if( (pCur->curFlags & BTCF_ValidOvfl)==0 ){
+      int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
+      if( pCur->aOverflow==0
+       || nOvfl*(int)sizeof(Pgno) > sqlite3MallocSize(pCur->aOverflow)
+      ){
+        Pgno *aNew;
+        if( sqlite3FaultSim(413) ){
+          aNew = 0;
+        }else{
+          aNew = (Pgno*)sqlite3Realloc(pCur->aOverflow, nOvfl*2*sizeof(Pgno));
+        }
+        if( aNew==0 ){
+          return SQLITE_NOMEM_BKPT;
+        }else{
+          pCur->aOverflow = aNew;
+        }
+      }
+      memset(pCur->aOverflow, 0, nOvfl*sizeof(Pgno));
+      pCur->curFlags |= BTCF_ValidOvfl;
+    }else{
+      /* Sanity check the validity of the overflow page cache */
+      assert( pCur->aOverflow[0]==nextPage
+           || pCur->aOverflow[0]==0
+           || CORRUPT_DB );
+      assert( pCur->aOverflow[0]!=0 || pCur->aOverflow[offset/ovflSize]==0 );
+
+      /* If the overflow page-list cache has been allocated and the
+      ** entry for the first required overflow page is valid, skip
+      ** directly to it.
+      */
+      if( pCur->aOverflow[offset/ovflSize] ){
+        iIdx = (offset/ovflSize);
+        nextPage = pCur->aOverflow[iIdx];
+        offset = (offset%ovflSize);
+      }
+    }
+
+    assert( rc==SQLITE_OK && amt>0 );
+    while( nextPage ){
+      /* If required, populate the overflow page-list cache. */
+      if( nextPage > pBt->nPage ) return SQLITE_CORRUPT_BKPT;
+      assert( pCur->aOverflow[iIdx]==0
+              || pCur->aOverflow[iIdx]==nextPage
+              || CORRUPT_DB );
+      pCur->aOverflow[iIdx] = nextPage;
+
+      if( offset>=ovflSize ){
+        /* The only reason to read this page is to obtain the page
+        ** number for the next page in the overflow chain. The page
+        ** data is not required. So first try to lookup the overflow
+        ** page-list cache, if any, then fall back to the getOverflowPage()
+        ** function.
+        */
+        assert( pCur->curFlags & BTCF_ValidOvfl );
+        assert( pCur->pBtree->db==pBt->db );
+        if( pCur->aOverflow[iIdx+1] ){
+          nextPage = pCur->aOverflow[iIdx+1];
+        }else{
+          rc = getOverflowPage(pBt, nextPage, 0, &nextPage);
+        }
+        offset -= ovflSize;
+      }else{
+        /* Need to read this page properly. It contains some of the
+        ** range of data that is being read (eOp==0) or written (eOp!=0).
+        */
+        int a = amt;
+        if( a + offset > ovflSize ){
+          a = ovflSize - offset;
+        }
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+        /* If all the following are true:
+        **
+        **   1) this is a read operation, and
+        **   2) data is required from the start of this overflow page, and
+        **   3) there are no dirty pages in the page-cache
+        **   4) the database is file-backed, and
+        **   5) the page is not in the WAL file
+        **   6) at least 4 bytes have already been read into the output buffer
+        **
+        ** then data can be read directly from the database file into the
+        ** output buffer, bypassing the page-cache altogether. This speeds
+        ** up loading large records that span many overflow pages.
+        */
+        if( eOp==0                                             /* (1) */
+         && offset==0                                          /* (2) */
+         && sqlite3PagerDirectReadOk(pBt->pPager, nextPage)    /* (3,4,5) */
+         && &pBuf[-4]>=pBufStart                               /* (6) */
+        ){
+          sqlite3_file *fd = sqlite3PagerFile(pBt->pPager);
+          u8 aSave[4];
+          u8 *aWrite = &pBuf[-4];
+          assert( aWrite>=pBufStart );                         /* due to (6) */
+          memcpy(aSave, aWrite, 4);
+          rc = sqlite3OsRead(fd, aWrite, a+4, (i64)pBt->pageSize*(nextPage-1));
+          nextPage = get4byte(aWrite);
+          memcpy(aWrite, aSave, 4);
+        }else
+#endif
+
+        {
+          DbPage *pDbPage;
+          rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage,
+              (eOp==0 ? PAGER_GET_READONLY : 0)
+          );
+          if( rc==SQLITE_OK ){
+            aPayload = sqlite3PagerGetData(pDbPage);
+            nextPage = get4byte(aPayload);
+            rc = copyPayload(&aPayload[offset+4], pBuf, a, eOp, pDbPage);
+            sqlite3PagerUnref(pDbPage);
+            offset = 0;
+          }
+        }
+        amt -= a;
+        if( amt==0 ) return rc;
+        pBuf += a;
+      }
+      if( rc ) break;
+      iIdx++;
+    }
+  }
+
+  if( rc==SQLITE_OK && amt>0 ){
+    /* Overflow chain ends prematurely */
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  return rc;
+}
+
+/*
+** Read part of the payload for the row at which that cursor pCur is currently
+** pointing.  "amt" bytes will be transferred into pBuf[].  The transfer
+** begins at "offset".
+**
+** pCur can be pointing to either a table or an index b-tree.
+** If pointing to a table btree, then the content section is read.  If
+** pCur is pointing to an index b-tree then the key section is read.
+**
+** For sqlite3BtreePayload(), the caller must ensure that pCur is pointing
+** to a valid row in the table.  For sqlite3BtreePayloadChecked(), the
+** cursor might be invalid or might need to be restored before being read.
+**
+** Return SQLITE_OK on success or an error code if anything goes
+** wrong.  An error is returned if "offset+amt" is larger than
+** the available payload.
+*/
+SQLITE_PRIVATE int sqlite3BtreePayload(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
+  assert( cursorHoldsMutex(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->iPage>=0 && pCur->pPage );
+  return accessPayload(pCur, offset, amt, (unsigned char*)pBuf, 0);
+}
+
+/*
+** This variant of sqlite3BtreePayload() works even if the cursor has not
+** in the CURSOR_VALID state.  It is only used by the sqlite3_blob_read()
+** interface.
+*/
+#ifndef SQLITE_OMIT_INCRBLOB
+static SQLITE_NOINLINE int accessPayloadChecked(
+  BtCursor *pCur,
+  u32 offset,
+  u32 amt,
+  void *pBuf
+){
+  int rc;
+  if ( pCur->eState==CURSOR_INVALID ){
+    return SQLITE_ABORT;
+  }
+  assert( cursorOwnsBtShared(pCur) );
+  rc = btreeRestoreCursorPosition(pCur);
+  return rc ? rc : accessPayload(pCur, offset, amt, pBuf, 0);
+}
+SQLITE_PRIVATE int sqlite3BtreePayloadChecked(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
+  if( pCur->eState==CURSOR_VALID ){
+    assert( cursorOwnsBtShared(pCur) );
+    return accessPayload(pCur, offset, amt, pBuf, 0);
+  }else{
+    return accessPayloadChecked(pCur, offset, amt, pBuf);
+  }
+}
+#endif /* SQLITE_OMIT_INCRBLOB */
+
+/*
+** Return a pointer to payload information from the entry that the
+** pCur cursor is pointing to.  The pointer is to the beginning of
+** the key if index btrees (pPage->intKey==0) and is the data for
+** table btrees (pPage->intKey==1). The number of bytes of available
+** key/data is written into *pAmt.  If *pAmt==0, then the value
+** returned will not be a valid pointer.
+**
+** This routine is an optimization.  It is common for the entire key
+** and data to fit on the local page and for there to be no overflow
+** pages.  When that is so, this routine can be used to access the
+** key and data without making a copy.  If the key and/or data spills
+** onto overflow pages, then accessPayload() must be used to reassemble
+** the key/data and copy it into a preallocated buffer.
+**
+** The pointer returned by this routine looks directly into the cached
+** page of the database.  The data might change or move the next time
+** any btree routine is called.
+*/
+static const void *fetchPayload(
+  BtCursor *pCur,      /* Cursor pointing to entry to read from */
+  u32 *pAmt            /* Write the number of available bytes here */
+){
+  int amt;
+  assert( pCur!=0 && pCur->iPage>=0 && pCur->pPage);
+  assert( pCur->eState==CURSOR_VALID );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->ix<pCur->pPage->nCell || CORRUPT_DB );
+  assert( pCur->info.nSize>0 );
+  assert( pCur->info.pPayload>pCur->pPage->aData || CORRUPT_DB );
+  assert( pCur->info.pPayload<pCur->pPage->aDataEnd ||CORRUPT_DB);
+  amt = pCur->info.nLocal;
+  if( amt>(int)(pCur->pPage->aDataEnd - pCur->info.pPayload) ){
+    /* There is too little space on the page for the expected amount
+    ** of local content. Database must be corrupt. */
+    assert( CORRUPT_DB );
+    amt = MAX(0, (int)(pCur->pPage->aDataEnd - pCur->info.pPayload));
+  }
+  *pAmt = (u32)amt;
+  return (void*)pCur->info.pPayload;
+}
+
+
+/*
+** For the entry that cursor pCur is point to, return as
+** many bytes of the key or data as are available on the local
+** b-tree page.  Write the number of available bytes into *pAmt.
+**
+** The pointer returned is ephemeral.  The key/data may move
+** or be destroyed on the next call to any Btree routine,
+** including calls from other threads against the same cache.
+** Hence, a mutex on the BtShared should be held prior to calling
+** this routine.
+**
+** These routines is used to get quick access to key and data
+** in the common case where no overflow pages are used.
+*/
+SQLITE_PRIVATE const void *sqlite3BtreePayloadFetch(BtCursor *pCur, u32 *pAmt){
+  return fetchPayload(pCur, pAmt);
+}
+
+
+/*
+** Move the cursor down to a new child page.  The newPgno argument is the
+** page number of the child page to move to.
+**
+** This function returns SQLITE_CORRUPT if the page-header flags field of
+** the new child page does not match the flags field of the parent (i.e.
+** if an intkey page appears to be the parent of a non-intkey page, or
+** vice-versa).
+*/
+static int moveToChild(BtCursor *pCur, u32 newPgno){
+  int rc;
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
+  assert( pCur->iPage>=0 );
+  if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  pCur->info.nSize = 0;
+  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+  pCur->aiIdx[pCur->iPage] = pCur->ix;
+  pCur->apPage[pCur->iPage] = pCur->pPage;
+  pCur->ix = 0;
+  pCur->iPage++;
+  rc = getAndInitPage(pCur->pBt, newPgno, &pCur->pPage, pCur->curPagerFlags);
+  assert( pCur->pPage!=0 || rc!=SQLITE_OK );
+  if( rc==SQLITE_OK
+   && (pCur->pPage->nCell<1 || pCur->pPage->intKey!=pCur->curIntKey)
+  ){
+    releasePage(pCur->pPage);
+    rc = SQLITE_CORRUPT_PGNO(newPgno);
+  }
+  if( rc ){
+    pCur->pPage = pCur->apPage[--pCur->iPage];
+  }
+  return rc;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Page pParent is an internal (non-leaf) tree page. This function
+** asserts that page number iChild is the left-child if the iIdx'th
+** cell in page pParent. Or, if iIdx is equal to the total number of
+** cells in pParent, that page number iChild is the right-child of
+** the page.
+*/
+static void assertParentIndex(MemPage *pParent, int iIdx, Pgno iChild){
+  if( CORRUPT_DB ) return;  /* The conditions tested below might not be true
+                            ** in a corrupt database */
+  assert( iIdx<=pParent->nCell );
+  if( iIdx==pParent->nCell ){
+    assert( get4byte(&pParent->aData[pParent->hdrOffset+8])==iChild );
+  }else{
+    assert( get4byte(findCell(pParent, iIdx))==iChild );
+  }
+}
+#else
+#  define assertParentIndex(x,y,z)
+#endif
+
+/*
+** Move the cursor up to the parent page.
+**
+** pCur->idx is set to the cell index that contains the pointer
+** to the page we are coming from.  If we are coming from the
+** right-most child page then pCur->idx is set to one more than
+** the largest cell index.
+*/
+static void moveToParent(BtCursor *pCur){
+  MemPage *pLeaf;
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->iPage>0 );
+  assert( pCur->pPage );
+  assertParentIndex(
+    pCur->apPage[pCur->iPage-1],
+    pCur->aiIdx[pCur->iPage-1],
+    pCur->pPage->pgno
+  );
+  testcase( pCur->aiIdx[pCur->iPage-1] > pCur->apPage[pCur->iPage-1]->nCell );
+  pCur->info.nSize = 0;
+  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+  pCur->ix = pCur->aiIdx[pCur->iPage-1];
+  pLeaf = pCur->pPage;
+  pCur->pPage = pCur->apPage[--pCur->iPage];
+  releasePageNotNull(pLeaf);
+}
+
+/*
+** Move the cursor to point to the root page of its b-tree structure.
+**
+** If the table has a virtual root page, then the cursor is moved to point
+** to the virtual root page instead of the actual root page. A table has a
+** virtual root page when the actual root page contains no cells and a
+** single child page. This can only happen with the table rooted at page 1.
+**
+** If the b-tree structure is empty, the cursor state is set to
+** CURSOR_INVALID and this routine returns SQLITE_EMPTY. Otherwise,
+** the cursor is set to point to the first cell located on the root
+** (or virtual root) page and the cursor state is set to CURSOR_VALID.
+**
+** If this function returns successfully, it may be assumed that the
+** page-header flags indicate that the [virtual] root-page is the expected
+** kind of b-tree page (i.e. if when opening the cursor the caller did not
+** specify a KeyInfo structure the flags byte is set to 0x05 or 0x0D,
+** indicating a table b-tree, or if the caller did specify a KeyInfo
+** structure the flags byte is set to 0x02 or 0x0A, indicating an index
+** b-tree).
+*/
+static int moveToRoot(BtCursor *pCur){
+  MemPage *pRoot;
+  int rc = SQLITE_OK;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( CURSOR_INVALID < CURSOR_REQUIRESEEK );
+  assert( CURSOR_VALID   < CURSOR_REQUIRESEEK );
+  assert( CURSOR_FAULT   > CURSOR_REQUIRESEEK );
+  assert( pCur->eState < CURSOR_REQUIRESEEK || pCur->iPage<0 );
+  assert( pCur->pgnoRoot>0 || pCur->iPage<0 );
+
+  if( pCur->iPage>=0 ){
+    if( pCur->iPage ){
+      releasePageNotNull(pCur->pPage);
+      while( --pCur->iPage ){
+        releasePageNotNull(pCur->apPage[pCur->iPage]);
+      }
+      pRoot = pCur->pPage = pCur->apPage[0];
+      goto skip_init;
+    }
+  }else if( pCur->pgnoRoot==0 ){
+    pCur->eState = CURSOR_INVALID;
+    return SQLITE_EMPTY;
+  }else{
+    assert( pCur->iPage==(-1) );
+    if( pCur->eState>=CURSOR_REQUIRESEEK ){
+      if( pCur->eState==CURSOR_FAULT ){
+        assert( pCur->skipNext!=SQLITE_OK );
+        return pCur->skipNext;
+      }
+      sqlite3BtreeClearCursor(pCur);
+    }
+    rc = getAndInitPage(pCur->pBt, pCur->pgnoRoot, &pCur->pPage,
+                        pCur->curPagerFlags);
+    if( rc!=SQLITE_OK ){
+      pCur->eState = CURSOR_INVALID;
+      return rc;
+    }
+    pCur->iPage = 0;
+    pCur->curIntKey = pCur->pPage->intKey;
+  }
+  pRoot = pCur->pPage;
+  assert( pRoot->pgno==pCur->pgnoRoot || CORRUPT_DB );
+
+  /* If pCur->pKeyInfo is not NULL, then the caller that opened this cursor
+  ** expected to open it on an index b-tree. Otherwise, if pKeyInfo is
+  ** NULL, the caller expects a table b-tree. If this is not the case,
+  ** return an SQLITE_CORRUPT error.
+  **
+  ** Earlier versions of SQLite assumed that this test could not fail
+  ** if the root page was already loaded when this function was called (i.e.
+  ** if pCur->iPage>=0). But this is not so if the database is corrupted
+  ** in such a way that page pRoot is linked into a second b-tree table
+  ** (or the freelist).  */
+  assert( pRoot->intKey==1 || pRoot->intKey==0 );
+  if( pRoot->isInit==0 || (pCur->pKeyInfo==0)!=pRoot->intKey ){
+    return SQLITE_CORRUPT_PAGE(pCur->pPage);
+  }
+
+skip_init:
+  pCur->ix = 0;
+  pCur->info.nSize = 0;
+  pCur->curFlags &= ~(BTCF_AtLast|BTCF_ValidNKey|BTCF_ValidOvfl);
+
+  if( pRoot->nCell>0 ){
+    pCur->eState = CURSOR_VALID;
+  }else if( !pRoot->leaf ){
+    Pgno subpage;
+    if( pRoot->pgno!=1 ) return SQLITE_CORRUPT_BKPT;
+    subpage = get4byte(&pRoot->aData[pRoot->hdrOffset+8]);
+    pCur->eState = CURSOR_VALID;
+    rc = moveToChild(pCur, subpage);
+  }else{
+    pCur->eState = CURSOR_INVALID;
+    rc = SQLITE_EMPTY;
+  }
+  return rc;
+}
+
+/*
+** Move the cursor down to the left-most leaf entry beneath the
+** entry to which it is currently pointing.
+**
+** The left-most leaf is the one with the smallest key - the first
+** in ascending order.
+*/
+static int moveToLeftmost(BtCursor *pCur){
+  Pgno pgno;
+  int rc = SQLITE_OK;
+  MemPage *pPage;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  while( rc==SQLITE_OK && !(pPage = pCur->pPage)->leaf ){
+    assert( pCur->ix<pPage->nCell );
+    pgno = get4byte(findCell(pPage, pCur->ix));
+    rc = moveToChild(pCur, pgno);
+  }
+  return rc;
+}
+
+/*
+** Move the cursor down to the right-most leaf entry beneath the
+** page to which it is currently pointing.  Notice the difference
+** between moveToLeftmost() and moveToRightmost().  moveToLeftmost()
+** finds the left-most entry beneath the *entry* whereas moveToRightmost()
+** finds the right-most entry beneath the *page*.
+**
+** The right-most entry is the one with the largest key - the last
+** key in ascending order.
+*/
+static int moveToRightmost(BtCursor *pCur){
+  Pgno pgno;
+  int rc = SQLITE_OK;
+  MemPage *pPage = 0;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pCur->eState==CURSOR_VALID );
+  while( !(pPage = pCur->pPage)->leaf ){
+    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    pCur->ix = pPage->nCell;
+    rc = moveToChild(pCur, pgno);
+    if( rc ) return rc;
+  }
+  pCur->ix = pPage->nCell-1;
+  assert( pCur->info.nSize==0 );
+  assert( (pCur->curFlags & BTCF_ValidNKey)==0 );
+  return SQLITE_OK;
+}
+
+/* Move the cursor to the first entry in the table.  Return SQLITE_OK
+** on success.  Set *pRes to 0 if the cursor actually points to something
+** or set *pRes to 1 if the table is empty.
+*/
+SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
+  int rc;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  rc = moveToRoot(pCur);
+  if( rc==SQLITE_OK ){
+    assert( pCur->pPage->nCell>0 );
+    *pRes = 0;
+    rc = moveToLeftmost(pCur);
+  }else if( rc==SQLITE_EMPTY ){
+    assert( pCur->pgnoRoot==0 || (pCur->pPage!=0 && pCur->pPage->nCell==0) );
+    *pRes = 1;
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+
+#ifdef SQLITE_DEBUG
+/* The cursors is CURSOR_VALID and has BTCF_AtLast set.  Verify that
+** this flags are true for a consistent database.
+**
+** This routine is is called from within assert() statements only.
+** It is an internal verification routine and does not appear in production
+** builds.
+*/
+static int cursorIsAtLastEntry(BtCursor *pCur){
+  int ii;
+  for(ii=0; ii<pCur->iPage; ii++){
+    if( pCur->aiIdx[ii]!=pCur->apPage[ii]->nCell ) return 0;
+  }
+  return pCur->ix==pCur->pPage->nCell-1 && pCur->pPage->leaf!=0;
+}
+#endif
+
+/* Move the cursor to the last entry in the table.  Return SQLITE_OK
+** on success.  Set *pRes to 0 if the cursor actually points to something
+** or set *pRes to 1 if the table is empty.
+*/
+static SQLITE_NOINLINE int btreeLast(BtCursor *pCur, int *pRes){
+  int rc = moveToRoot(pCur);
+  if( rc==SQLITE_OK ){
+    assert( pCur->eState==CURSOR_VALID );
+    *pRes = 0;
+    rc = moveToRightmost(pCur);
+    if( rc==SQLITE_OK ){
+      pCur->curFlags |= BTCF_AtLast;
+    }else{
+      pCur->curFlags &= ~BTCF_AtLast;
+    }
+  }else if( rc==SQLITE_EMPTY ){
+    assert( pCur->pgnoRoot==0 || pCur->pPage->nCell==0 );
+    *pRes = 1;
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor *pCur, int *pRes){
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+
+  /* If the cursor already points to the last entry, this is a no-op. */
+  if( CURSOR_VALID==pCur->eState && (pCur->curFlags & BTCF_AtLast)!=0 ){
+    assert( cursorIsAtLastEntry(pCur) || CORRUPT_DB );
+    *pRes = 0;
+    return SQLITE_OK;
+  }
+  return btreeLast(pCur, pRes);
+}
+
+/* Move the cursor so that it points to an entry in a table (a.k.a INTKEY)
+** table near the key intKey.   Return a success code.
+**
+** If an exact match is not found, then the cursor is always
+** left pointing at a leaf page which would hold the entry if it
+** were present.  The cursor might point to an entry that comes
+** before or after the key.
+**
+** An integer is written into *pRes which is the result of
+** comparing the key with the entry to which the cursor is
+** pointing.  The meaning of the integer written into
+** *pRes is as follows:
+**
+**     *pRes<0      The cursor is left pointing at an entry that
+**                  is smaller than intKey or if the table is empty
+**                  and the cursor is therefore left point to nothing.
+**
+**     *pRes==0     The cursor is left pointing at an entry that
+**                  exactly matches intKey.
+**
+**     *pRes>0      The cursor is left pointing at an entry that
+**                  is larger than intKey.
+*/
+SQLITE_PRIVATE int sqlite3BtreeTableMoveto(
+  BtCursor *pCur,          /* The cursor to be moved */
+  i64 intKey,              /* The table key */
+  int biasRight,           /* If true, bias the search to the high end */
+  int *pRes                /* Write search results here */
+){
+  int rc;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  assert( pRes );
+  assert( pCur->pKeyInfo==0 );
+  assert( pCur->eState!=CURSOR_VALID || pCur->curIntKey!=0 );
+
+  /* If the cursor is already positioned at the point we are trying
+  ** to move to, then just return without doing any work */
+  if( pCur->eState==CURSOR_VALID && (pCur->curFlags & BTCF_ValidNKey)!=0 ){
+    if( pCur->info.nKey==intKey ){
+      *pRes = 0;
+      return SQLITE_OK;
+    }
+    if( pCur->info.nKey<intKey ){
+      if( (pCur->curFlags & BTCF_AtLast)!=0 ){
+        assert( cursorIsAtLastEntry(pCur) || CORRUPT_DB );
+        *pRes = -1;
+        return SQLITE_OK;
+      }
+      /* If the requested key is one more than the previous key, then
+      ** try to get there using sqlite3BtreeNext() rather than a full
+      ** binary search.  This is an optimization only.  The correct answer
+      ** is still obtained without this case, only a little more slowly. */
+      if( pCur->info.nKey+1==intKey ){
+        *pRes = 0;
+        rc = sqlite3BtreeNext(pCur, 0);
+        if( rc==SQLITE_OK ){
+          getCellInfo(pCur);
+          if( pCur->info.nKey==intKey ){
+            return SQLITE_OK;
+          }
+        }else if( rc!=SQLITE_DONE ){
+          return rc;
+        }
+      }
+    }
+  }
+
+#ifdef SQLITE_DEBUG
+  pCur->pBtree->nSeek++;   /* Performance measurement during testing */
+#endif
+
+  rc = moveToRoot(pCur);
+  if( rc ){
+    if( rc==SQLITE_EMPTY ){
+      assert( pCur->pgnoRoot==0 || pCur->pPage->nCell==0 );
+      *pRes = -1;
+      return SQLITE_OK;
+    }
+    return rc;
+  }
+  assert( pCur->pPage );
+  assert( pCur->pPage->isInit );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->pPage->nCell > 0 );
+  assert( pCur->iPage==0 || pCur->apPage[0]->intKey==pCur->curIntKey );
+  assert( pCur->curIntKey );
+
+  for(;;){
+    int lwr, upr, idx, c;
+    Pgno chldPg;
+    MemPage *pPage = pCur->pPage;
+    u8 *pCell;                          /* Pointer to current cell in pPage */
+
+    /* pPage->nCell must be greater than zero. If this is the root-page
+    ** the cursor would have been INVALID above and this for(;;) loop
+    ** not run. If this is not the root-page, then the moveToChild() routine
+    ** would have already detected db corruption. Similarly, pPage must
+    ** be the right kind (index or table) of b-tree page. Otherwise
+    ** a moveToChild() or moveToRoot() call would have detected corruption.  */
+    assert( pPage->nCell>0 );
+    assert( pPage->intKey );
+    lwr = 0;
+    upr = pPage->nCell-1;
+    assert( biasRight==0 || biasRight==1 );
+    idx = upr>>(1-biasRight); /* idx = biasRight ? upr : (lwr+upr)/2; */
+    for(;;){
+      i64 nCellKey;
+      pCell = findCellPastPtr(pPage, idx);
+      if( pPage->intKeyLeaf ){
+        while( 0x80 <= *(pCell++) ){
+          if( pCell>=pPage->aDataEnd ){
+            return SQLITE_CORRUPT_PAGE(pPage);
+          }
+        }
+      }
+      getVarint(pCell, (u64*)&nCellKey);
+      if( nCellKey<intKey ){
+        lwr = idx+1;
+        if( lwr>upr ){ c = -1; break; }
+      }else if( nCellKey>intKey ){
+        upr = idx-1;
+        if( lwr>upr ){ c = +1; break; }
+      }else{
+        assert( nCellKey==intKey );
+        pCur->ix = (u16)idx;
+        if( !pPage->leaf ){
+          lwr = idx;
+          goto moveto_table_next_layer;
+        }else{
+          pCur->curFlags |= BTCF_ValidNKey;
+          pCur->info.nKey = nCellKey;
+          pCur->info.nSize = 0;
+          *pRes = 0;
+          return SQLITE_OK;
+        }
+      }
+      assert( lwr+upr>=0 );
+      idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2; */
+    }
+    assert( lwr==upr+1 || !pPage->leaf );
+    assert( pPage->isInit );
+    if( pPage->leaf ){
+      assert( pCur->ix<pCur->pPage->nCell );
+      pCur->ix = (u16)idx;
+      *pRes = c;
+      rc = SQLITE_OK;
+      goto moveto_table_finish;
+    }
+moveto_table_next_layer:
+    if( lwr>=pPage->nCell ){
+      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    }else{
+      chldPg = get4byte(findCell(pPage, lwr));
+    }
+    pCur->ix = (u16)lwr;
+    rc = moveToChild(pCur, chldPg);
+    if( rc ) break;
+  }
+moveto_table_finish:
+  pCur->info.nSize = 0;
+  assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
+  return rc;
+}
+
+/*
+** Compare the "idx"-th cell on the page the cursor pCur is currently
+** pointing to to pIdxKey using xRecordCompare.  Return negative or
+** zero if the cell is less than or equal pIdxKey.  Return positive
+** if unknown.
+**
+**    Return value negative:     Cell at pCur[idx] less than pIdxKey
+**
+**    Return value is zero:      Cell at pCur[idx] equals pIdxKey
+**
+**    Return value positive:     Nothing is known about the relationship
+**                               of the cell at pCur[idx] and pIdxKey.
+**
+** This routine is part of an optimization.  It is always safe to return
+** a positive value as that will cause the optimization to be skipped.
+*/
+static int indexCellCompare(
+  BtCursor *pCur,
+  int idx,
+  UnpackedRecord *pIdxKey,
+  RecordCompare xRecordCompare
+){
+  MemPage *pPage = pCur->pPage;
+  int c;
+  int nCell;  /* Size of the pCell cell in bytes */
+  u8 *pCell = findCellPastPtr(pPage, idx);
+
+  nCell = pCell[0];
+  if( nCell<=pPage->max1bytePayload ){
+    /* This branch runs if the record-size field of the cell is a
+    ** single byte varint and the record fits entirely on the main
+    ** b-tree page.  */
+    testcase( pCell+nCell+1==pPage->aDataEnd );
+    c = xRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
+  }else if( !(pCell[1] & 0x80)
+    && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
+  ){
+    /* The record-size field is a 2 byte varint and the record
+    ** fits entirely on the main b-tree page.  */
+    testcase( pCell+nCell+2==pPage->aDataEnd );
+    c = xRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
+  }else{
+    /* If the record extends into overflow pages, do not attempt
+    ** the optimization. */
+    c = 99;
+  }
+  return c;
+}
+
+/*
+** Return true (non-zero) if pCur is current pointing to the last
+** page of a table.
+*/
+static int cursorOnLastPage(BtCursor *pCur){
+  int i;
+  assert( pCur->eState==CURSOR_VALID );
+  for(i=0; i<pCur->iPage; i++){
+    MemPage *pPage = pCur->apPage[i];
+    if( pCur->aiIdx[i]<pPage->nCell ) return 0;
+  }
+  return 1;
+}
+
+/* Move the cursor so that it points to an entry in an index table
+** near the key pIdxKey.   Return a success code.
+**
+** If an exact match is not found, then the cursor is always
+** left pointing at a leaf page which would hold the entry if it
+** were present.  The cursor might point to an entry that comes
+** before or after the key.
+**
+** An integer is written into *pRes which is the result of
+** comparing the key with the entry to which the cursor is
+** pointing.  The meaning of the integer written into
+** *pRes is as follows:
+**
+**     *pRes<0      The cursor is left pointing at an entry that
+**                  is smaller than pIdxKey or if the table is empty
+**                  and the cursor is therefore left point to nothing.
+**
+**     *pRes==0     The cursor is left pointing at an entry that
+**                  exactly matches pIdxKey.
+**
+**     *pRes>0      The cursor is left pointing at an entry that
+**                  is larger than pIdxKey.
+**
+** The pIdxKey->eqSeen field is set to 1 if there
+** exists an entry in the table that exactly matches pIdxKey.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIndexMoveto(
+  BtCursor *pCur,          /* The cursor to be moved */
+  UnpackedRecord *pIdxKey, /* Unpacked index key */
+  int *pRes                /* Write search results here */
+){
+  int rc;
+  RecordCompare xRecordCompare;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+  assert( pRes );
+  assert( pCur->pKeyInfo!=0 );
+
+#ifdef SQLITE_DEBUG
+  pCur->pBtree->nSeek++;   /* Performance measurement during testing */
+#endif
+
+  xRecordCompare = sqlite3VdbeFindCompare(pIdxKey);
+  pIdxKey->errCode = 0;
+  assert( pIdxKey->default_rc==1
+       || pIdxKey->default_rc==0
+       || pIdxKey->default_rc==-1
+  );
+
+
+  /* Check to see if we can skip a lot of work.  Two cases:
+  **
+  **    (1) If the cursor is already pointing to the very last cell
+  **        in the table and the pIdxKey search key is greater than or
+  **        equal to that last cell, then no movement is required.
+  **
+  **    (2) If the cursor is on the last page of the table and the first
+  **        cell on that last page is less than or equal to the pIdxKey
+  **        search key, then we can start the search on the current page
+  **        without needing to go back to root.
+  */
+  if( pCur->eState==CURSOR_VALID
+   && pCur->pPage->leaf
+   && cursorOnLastPage(pCur)
+  ){
+    int c;
+    if( pCur->ix==pCur->pPage->nCell-1
+     && (c = indexCellCompare(pCur, pCur->ix, pIdxKey, xRecordCompare))<=0
+     && pIdxKey->errCode==SQLITE_OK
+    ){
+      *pRes = c;
+      return SQLITE_OK;  /* Cursor already pointing at the correct spot */
+    }
+    if( pCur->iPage>0
+     && indexCellCompare(pCur, 0, pIdxKey, xRecordCompare)<=0
+     && pIdxKey->errCode==SQLITE_OK
+    ){
+      pCur->curFlags &= ~(BTCF_ValidOvfl|BTCF_AtLast);
+      if( !pCur->pPage->isInit ){
+        return SQLITE_CORRUPT_BKPT;
+      }
+      goto bypass_moveto_root;  /* Start search on the current page */
+    }
+    pIdxKey->errCode = SQLITE_OK;
+  }
+
+  rc = moveToRoot(pCur);
+  if( rc ){
+    if( rc==SQLITE_EMPTY ){
+      assert( pCur->pgnoRoot==0 || pCur->pPage->nCell==0 );
+      *pRes = -1;
+      return SQLITE_OK;
+    }
+    return rc;
+  }
+
+bypass_moveto_root:
+  assert( pCur->pPage );
+  assert( pCur->pPage->isInit );
+  assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->pPage->nCell > 0 );
+  assert( pCur->curIntKey==0 );
+  assert( pIdxKey!=0 );
+  for(;;){
+    int lwr, upr, idx, c;
+    Pgno chldPg;
+    MemPage *pPage = pCur->pPage;
+    u8 *pCell;                          /* Pointer to current cell in pPage */
+
+    /* pPage->nCell must be greater than zero. If this is the root-page
+    ** the cursor would have been INVALID above and this for(;;) loop
+    ** not run. If this is not the root-page, then the moveToChild() routine
+    ** would have already detected db corruption. Similarly, pPage must
+    ** be the right kind (index or table) of b-tree page. Otherwise
+    ** a moveToChild() or moveToRoot() call would have detected corruption.  */
+    assert( pPage->nCell>0 );
+    assert( pPage->intKey==0 );
+    lwr = 0;
+    upr = pPage->nCell-1;
+    idx = upr>>1; /* idx = (lwr+upr)/2; */
+    for(;;){
+      int nCell;  /* Size of the pCell cell in bytes */
+      pCell = findCellPastPtr(pPage, idx);
+
+      /* The maximum supported page-size is 65536 bytes. This means that
+      ** the maximum number of record bytes stored on an index B-Tree
+      ** page is less than 16384 bytes and may be stored as a 2-byte
+      ** varint. This information is used to attempt to avoid parsing
+      ** the entire cell by checking for the cases where the record is
+      ** stored entirely within the b-tree page by inspecting the first
+      ** 2 bytes of the cell.
+      */
+      nCell = pCell[0];
+      if( nCell<=pPage->max1bytePayload ){
+        /* This branch runs if the record-size field of the cell is a
+        ** single byte varint and the record fits entirely on the main
+        ** b-tree page.  */
+        testcase( pCell+nCell+1==pPage->aDataEnd );
+        c = xRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
+      }else if( !(pCell[1] & 0x80)
+        && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
+      ){
+        /* The record-size field is a 2 byte varint and the record
+        ** fits entirely on the main b-tree page.  */
+        testcase( pCell+nCell+2==pPage->aDataEnd );
+        c = xRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
+      }else{
+        /* The record flows over onto one or more overflow pages. In
+        ** this case the whole cell needs to be parsed, a buffer allocated
+        ** and accessPayload() used to retrieve the record into the
+        ** buffer before VdbeRecordCompare() can be called.
+        **
+        ** If the record is corrupt, the xRecordCompare routine may read
+        ** up to two varints past the end of the buffer. An extra 18
+        ** bytes of padding is allocated at the end of the buffer in
+        ** case this happens.  */
+        void *pCellKey;
+        u8 * const pCellBody = pCell - pPage->childPtrSize;
+        const int nOverrun = 18;  /* Size of the overrun padding */
+        pPage->xParseCell(pPage, pCellBody, &pCur->info);
+        nCell = (int)pCur->info.nKey;
+        testcase( nCell<0 );   /* True if key size is 2^32 or more */
+        testcase( nCell==0 );  /* Invalid key size:  0x80 0x80 0x00 */
+        testcase( nCell==1 );  /* Invalid key size:  0x80 0x80 0x01 */
+        testcase( nCell==2 );  /* Minimum legal index key size */
+        if( nCell<2 || nCell/pCur->pBt->usableSize>pCur->pBt->nPage ){
+          rc = SQLITE_CORRUPT_PAGE(pPage);
+          goto moveto_index_finish;
+        }
+        pCellKey = sqlite3Malloc( nCell+nOverrun );
+        if( pCellKey==0 ){
+          rc = SQLITE_NOMEM_BKPT;
+          goto moveto_index_finish;
+        }
+        pCur->ix = (u16)idx;
+        rc = accessPayload(pCur, 0, nCell, (unsigned char*)pCellKey, 0);
+        memset(((u8*)pCellKey)+nCell,0,nOverrun); /* Fix uninit warnings */
+        pCur->curFlags &= ~BTCF_ValidOvfl;
+        if( rc ){
+          sqlite3_free(pCellKey);
+          goto moveto_index_finish;
+        }
+        c = sqlite3VdbeRecordCompare(nCell, pCellKey, pIdxKey);
+        sqlite3_free(pCellKey);
+      }
+      assert(
+          (pIdxKey->errCode!=SQLITE_CORRUPT || c==0)
+       && (pIdxKey->errCode!=SQLITE_NOMEM || pCur->pBtree->db->mallocFailed)
+      );
+      if( c<0 ){
+        lwr = idx+1;
+      }else if( c>0 ){
+        upr = idx-1;
+      }else{
+        assert( c==0 );
+        *pRes = 0;
+        rc = SQLITE_OK;
+        pCur->ix = (u16)idx;
+        if( pIdxKey->errCode ) rc = SQLITE_CORRUPT_BKPT;
+        goto moveto_index_finish;
+      }
+      if( lwr>upr ) break;
+      assert( lwr+upr>=0 );
+      idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2 */
+    }
+    assert( lwr==upr+1 || (pPage->intKey && !pPage->leaf) );
+    assert( pPage->isInit );
+    if( pPage->leaf ){
+      assert( pCur->ix<pCur->pPage->nCell || CORRUPT_DB );
+      pCur->ix = (u16)idx;
+      *pRes = c;
+      rc = SQLITE_OK;
+      goto moveto_index_finish;
+    }
+    if( lwr>=pPage->nCell ){
+      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    }else{
+      chldPg = get4byte(findCell(pPage, lwr));
+    }
+
+    /* This block is similar to an in-lined version of:
+    **
+    **    pCur->ix = (u16)lwr;
+    **    rc = moveToChild(pCur, chldPg);
+    **    if( rc ) break;
+    */
+    pCur->info.nSize = 0;
+    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+    if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+    pCur->aiIdx[pCur->iPage] = (u16)lwr;
+    pCur->apPage[pCur->iPage] = pCur->pPage;
+    pCur->ix = 0;
+    pCur->iPage++;
+    rc = getAndInitPage(pCur->pBt, chldPg, &pCur->pPage, pCur->curPagerFlags);
+    if( rc==SQLITE_OK
+     && (pCur->pPage->nCell<1 || pCur->pPage->intKey!=pCur->curIntKey)
+    ){
+      releasePage(pCur->pPage);
+      rc = SQLITE_CORRUPT_PGNO(chldPg);
+    }
+    if( rc ){
+      pCur->pPage = pCur->apPage[--pCur->iPage];
+      break;
+    }
+    /*
+    ***** End of in-lined moveToChild() call */
+ }
+moveto_index_finish:
+  pCur->info.nSize = 0;
+  assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
+  return rc;
+}
+
+
+/*
+** Return TRUE if the cursor is not pointing at an entry of the table.
+**
+** TRUE will be returned after a call to sqlite3BtreeNext() moves
+** past the last entry in the table or sqlite3BtreePrev() moves past
+** the first entry.  TRUE is also returned if the table is empty.
+*/
+SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor *pCur){
+  /* TODO: What if the cursor is in CURSOR_REQUIRESEEK but all table entries
+  ** have been deleted? This API will need to change to return an error code
+  ** as well as the boolean result value.
+  */
+  return (CURSOR_VALID!=pCur->eState);
+}
+
+/*
+** Return an estimate for the number of rows in the table that pCur is
+** pointing to.  Return a negative number if no estimate is currently
+** available.
+*/
+SQLITE_PRIVATE i64 sqlite3BtreeRowCountEst(BtCursor *pCur){
+  i64 n;
+  u8 i;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
+
+  /* Currently this interface is only called by the OP_IfSizeBetween
+  ** opcode and the OP_Count opcode with P3=1.  In either case,
+  ** the cursor will always be valid unless the btree is empty. */
+  if( pCur->eState!=CURSOR_VALID ) return 0;
+  if( NEVER(pCur->pPage->leaf==0) ) return -1;
+
+  n = pCur->pPage->nCell;
+  for(i=0; i<pCur->iPage; i++){
+    n *= pCur->apPage[i]->nCell;
+  }
+  return n;
+}
+
+/*
+** Advance the cursor to the next entry in the database.
+** Return value:
+**
+**    SQLITE_OK        success
+**    SQLITE_DONE      cursor is already pointing at the last element
+**    otherwise        some kind of error occurred
+**
+** The main entry point is sqlite3BtreeNext().  That routine is optimized
+** for the common case of merely incrementing the cell counter BtCursor.aiIdx
+** to the next cell on the current page.  The (slower) btreeNext() helper
+** routine is called when it is necessary to move to a different page or
+** to restore the cursor.
+**
+** If bit 0x01 of the F argument in sqlite3BtreeNext(C,F) is 1, then the
+** cursor corresponds to an SQL index and this routine could have been
+** skipped if the SQL index had been a unique index.  The F argument
+** is a hint to the implement.  SQLite btree implementation does not use
+** this hint, but COMDB2 does.
+*/
+static SQLITE_NOINLINE int btreeNext(BtCursor *pCur){
+  int rc;
+  int idx;
+  MemPage *pPage;
+
+  assert( cursorOwnsBtShared(pCur) );
+  if( pCur->eState!=CURSOR_VALID ){
+    assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
+    rc = restoreCursorPosition(pCur);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( CURSOR_INVALID==pCur->eState ){
+      return SQLITE_DONE;
+    }
+    if( pCur->eState==CURSOR_SKIPNEXT ){
+      pCur->eState = CURSOR_VALID;
+      if( pCur->skipNext>0 ) return SQLITE_OK;
+    }
+  }
+
+  pPage = pCur->pPage;
+  idx = ++pCur->ix;
+  if( sqlite3FaultSim(412) ) pPage->isInit = 0;
+  if( !pPage->isInit ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+
+  if( idx>=pPage->nCell ){
+    if( !pPage->leaf ){
+      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
+      if( rc ) return rc;
+      return moveToLeftmost(pCur);
+    }
+    do{
+      if( pCur->iPage==0 ){
+        pCur->eState = CURSOR_INVALID;
+        return SQLITE_DONE;
+      }
+      moveToParent(pCur);
+      pPage = pCur->pPage;
+    }while( pCur->ix>=pPage->nCell );
+    if( pPage->intKey ){
+      return sqlite3BtreeNext(pCur, 0);
+    }else{
+      return SQLITE_OK;
+    }
+  }
+  if( pPage->leaf ){
+    return SQLITE_OK;
+  }else{
+    return moveToLeftmost(pCur);
+  }
+}
+SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor *pCur, int flags){
+  MemPage *pPage;
+  UNUSED_PARAMETER( flags );  /* Used in COMDB2 but not native SQLite */
+  assert( cursorOwnsBtShared(pCur) );
+  assert( flags==0 || flags==1 );
+  pCur->info.nSize = 0;
+  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+  if( pCur->eState!=CURSOR_VALID ) return btreeNext(pCur);
+  pPage = pCur->pPage;
+  if( (++pCur->ix)>=pPage->nCell ){
+    pCur->ix--;
+    return btreeNext(pCur);
+  }
+  if( pPage->leaf ){
+    return SQLITE_OK;
+  }else{
+    return moveToLeftmost(pCur);
+  }
+}
+
+/*
+** Step the cursor to the back to the previous entry in the database.
+** Return values:
+**
+**     SQLITE_OK     success
+**     SQLITE_DONE   the cursor is already on the first element of the table
+**     otherwise     some kind of error occurred
+**
+** The main entry point is sqlite3BtreePrevious().  That routine is optimized
+** for the common case of merely decrementing the cell counter BtCursor.aiIdx
+** to the previous cell on the current page.  The (slower) btreePrevious()
+** helper routine is called when it is necessary to move to a different page
+** or to restore the cursor.
+**
+** If bit 0x01 of the F argument to sqlite3BtreePrevious(C,F) is 1, then
+** the cursor corresponds to an SQL index and this routine could have been
+** skipped if the SQL index had been a unique index.  The F argument is a
+** hint to the implement.  The native SQLite btree implementation does not
+** use this hint, but COMDB2 does.
+*/
+static SQLITE_NOINLINE int btreePrevious(BtCursor *pCur){
+  int rc;
+  MemPage *pPage;
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( (pCur->curFlags & (BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey))==0 );
+  assert( pCur->info.nSize==0 );
+  if( pCur->eState!=CURSOR_VALID ){
+    rc = restoreCursorPosition(pCur);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( CURSOR_INVALID==pCur->eState ){
+      return SQLITE_DONE;
+    }
+    if( CURSOR_SKIPNEXT==pCur->eState ){
+      pCur->eState = CURSOR_VALID;
+      if( pCur->skipNext<0 ) return SQLITE_OK;
+    }
+  }
+
+  pPage = pCur->pPage;
+  if( sqlite3FaultSim(412) ) pPage->isInit = 0;
+  if( !pPage->isInit ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( !pPage->leaf ){
+    int idx = pCur->ix;
+    rc = moveToChild(pCur, get4byte(findCell(pPage, idx)));
+    if( rc ) return rc;
+    rc = moveToRightmost(pCur);
+  }else{
+    while( pCur->ix==0 ){
+      if( pCur->iPage==0 ){
+        pCur->eState = CURSOR_INVALID;
+        return SQLITE_DONE;
+      }
+      moveToParent(pCur);
+    }
+    assert( pCur->info.nSize==0 );
+    assert( (pCur->curFlags & (BTCF_ValidOvfl))==0 );
+
+    pCur->ix--;
+    pPage = pCur->pPage;
+    if( pPage->intKey && !pPage->leaf ){
+      rc = sqlite3BtreePrevious(pCur, 0);
+    }else{
+      rc = SQLITE_OK;
+    }
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor *pCur, int flags){
+  assert( cursorOwnsBtShared(pCur) );
+  assert( flags==0 || flags==1 );
+  UNUSED_PARAMETER( flags );  /* Used in COMDB2 but not native SQLite */
+  pCur->curFlags &= ~(BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey);
+  pCur->info.nSize = 0;
+  if( pCur->eState!=CURSOR_VALID
+   || pCur->ix==0
+   || pCur->pPage->leaf==0
+  ){
+    return btreePrevious(pCur);
+  }
+  pCur->ix--;
+  return SQLITE_OK;
+}
+
+/*
+** Allocate a new page from the database file.
+**
+** The new page is marked as dirty.  (In other words, sqlite3PagerWrite()
+** has already been called on the new page.)  The new page has also
+** been referenced and the calling routine is responsible for calling
+** sqlite3PagerUnref() on the new page when it is done.
+**
+** SQLITE_OK is returned on success.  Any other return value indicates
+** an error.  *ppPage is set to NULL in the event of an error.
+**
+** If the "nearby" parameter is not 0, then an effort is made to
+** locate a page close to the page number "nearby".  This can be used in an
+** attempt to keep related pages close to each other in the database file,
+** which in turn can make database access faster.
+**
+** If the eMode parameter is BTALLOC_EXACT and the nearby page exists
+** anywhere on the free-list, then it is guaranteed to be returned.  If
+** eMode is BTALLOC_LT then the page returned will be less than or equal
+** to nearby if any such page exists.  If eMode is BTALLOC_ANY then there
+** are no restrictions on which page is returned.
+*/
+static int allocateBtreePage(
+  BtShared *pBt,         /* The btree */
+  MemPage **ppPage,      /* Store pointer to the allocated page here */
+  Pgno *pPgno,           /* Store the page number here */
+  Pgno nearby,           /* Search for a page near this one */
+  u8 eMode               /* BTALLOC_EXACT, BTALLOC_LT, or BTALLOC_ANY */
+){
+  MemPage *pPage1;
+  int rc;
+  u32 n;     /* Number of pages on the freelist */
+  u32 k;     /* Number of leaves on the trunk of the freelist */
+  MemPage *pTrunk = 0;
+  MemPage *pPrevTrunk = 0;
+  Pgno mxPage;     /* Total size of the database file */
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( eMode==BTALLOC_ANY || (nearby>0 && IfNotOmitAV(pBt->autoVacuum)) );
+  pPage1 = pBt->pPage1;
+  mxPage = btreePagecount(pBt);
+  /* EVIDENCE-OF: R-21003-45125 The 4-byte big-endian integer at offset 36
+  ** stores the total number of pages on the freelist. */
+  n = get4byte(&pPage1->aData[36]);
+  testcase( n==mxPage-1 );
+  if( n>=mxPage ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( n>0 ){
+    /* There are pages on the freelist.  Reuse one of those pages. */
+    Pgno iTrunk;
+    u8 searchList = 0; /* If the free-list must be searched for 'nearby' */
+    u32 nSearch = 0;   /* Count of the number of search attempts */
+
+    /* If eMode==BTALLOC_EXACT and a query of the pointer-map
+    ** shows that the page 'nearby' is somewhere on the free-list, then
+    ** the entire-list will be searched for that page.
+    */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( eMode==BTALLOC_EXACT ){
+      if( nearby<=mxPage ){
+        u8 eType;
+        assert( nearby>0 );
+        assert( pBt->autoVacuum );
+        rc = ptrmapGet(pBt, nearby, &eType, 0);
+        if( rc ) return rc;
+        if( eType==PTRMAP_FREEPAGE ){
+          searchList = 1;
+        }
+      }
+    }else if( eMode==BTALLOC_LE ){
+      searchList = 1;
+    }
+#endif
+
+    /* Decrement the free-list count by 1. Set iTrunk to the index of the
+    ** first free-list trunk page. iPrevTrunk is initially 1.
+    */
+    rc = sqlite3PagerWrite(pPage1->pDbPage);
+    if( rc ) return rc;
+    put4byte(&pPage1->aData[36], n-1);
+
+    /* The code within this loop is run only once if the 'searchList' variable
+    ** is not true. Otherwise, it runs once for each trunk-page on the
+    ** free-list until the page 'nearby' is located (eMode==BTALLOC_EXACT)
+    ** or until a page less than 'nearby' is located (eMode==BTALLOC_LT)
+    */
+    do {
+      pPrevTrunk = pTrunk;
+      if( pPrevTrunk ){
+        /* EVIDENCE-OF: R-01506-11053 The first integer on a freelist trunk page
+        ** is the page number of the next freelist trunk page in the list or
+        ** zero if this is the last freelist trunk page. */
+        iTrunk = get4byte(&pPrevTrunk->aData[0]);
+      }else{
+        /* EVIDENCE-OF: R-59841-13798 The 4-byte big-endian integer at offset 32
+        ** stores the page number of the first page of the freelist, or zero if
+        ** the freelist is empty. */
+        iTrunk = get4byte(&pPage1->aData[32]);
+      }
+      testcase( iTrunk==mxPage );
+      if( iTrunk>mxPage || nSearch++ > n ){
+        rc = SQLITE_CORRUPT_PGNO(pPrevTrunk ? pPrevTrunk->pgno : 1);
+      }else{
+        rc = btreeGetUnusedPage(pBt, iTrunk, &pTrunk, 0);
+      }
+      if( rc ){
+        pTrunk = 0;
+        goto end_allocate_page;
+      }
+      assert( pTrunk!=0 );
+      assert( pTrunk->aData!=0 );
+      /* EVIDENCE-OF: R-13523-04394 The second integer on a freelist trunk page
+      ** is the number of leaf page pointers to follow. */
+      k = get4byte(&pTrunk->aData[4]);
+      if( k==0 && !searchList ){
+        /* The trunk has no leaves and the list is not being searched.
+        ** So extract the trunk page itself and use it as the newly
+        ** allocated page */
+        assert( pPrevTrunk==0 );
+        rc = sqlite3PagerWrite(pTrunk->pDbPage);
+        if( rc ){
+          goto end_allocate_page;
+        }
+        *pPgno = iTrunk;
+        memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
+        *ppPage = pTrunk;
+        pTrunk = 0;
+        TRACE(("ALLOCATE: %u trunk - %u free pages left\n", *pPgno, n-1));
+      }else if( k>(u32)(pBt->usableSize/4 - 2) ){
+        /* Value of k is out of range.  Database corruption */
+        rc = SQLITE_CORRUPT_PGNO(iTrunk);
+        goto end_allocate_page;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      }else if( searchList
+            && (nearby==iTrunk || (iTrunk<nearby && eMode==BTALLOC_LE))
+      ){
+        /* The list is being searched and this trunk page is the page
+        ** to allocate, regardless of whether it has leaves.
+        */
+        *pPgno = iTrunk;
+        *ppPage = pTrunk;
+        searchList = 0;
+        rc = sqlite3PagerWrite(pTrunk->pDbPage);
+        if( rc ){
+          goto end_allocate_page;
+        }
+        if( k==0 ){
+          if( !pPrevTrunk ){
+            memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
+          }else{
+            rc = sqlite3PagerWrite(pPrevTrunk->pDbPage);
+            if( rc!=SQLITE_OK ){
+              goto end_allocate_page;
+            }
+            memcpy(&pPrevTrunk->aData[0], &pTrunk->aData[0], 4);
+          }
+        }else{
+          /* The trunk page is required by the caller but it contains
+          ** pointers to free-list leaves. The first leaf becomes a trunk
+          ** page in this case.
+          */
+          MemPage *pNewTrunk;
+          Pgno iNewTrunk = get4byte(&pTrunk->aData[8]);
+          if( iNewTrunk>mxPage ){
+            rc = SQLITE_CORRUPT_PGNO(iTrunk);
+            goto end_allocate_page;
+          }
+          testcase( iNewTrunk==mxPage );
+          rc = btreeGetUnusedPage(pBt, iNewTrunk, &pNewTrunk, 0);
+          if( rc!=SQLITE_OK ){
+            goto end_allocate_page;
+          }
+          rc = sqlite3PagerWrite(pNewTrunk->pDbPage);
+          if( rc!=SQLITE_OK ){
+            releasePage(pNewTrunk);
+            goto end_allocate_page;
+          }
+          memcpy(&pNewTrunk->aData[0], &pTrunk->aData[0], 4);
+          put4byte(&pNewTrunk->aData[4], k-1);
+          memcpy(&pNewTrunk->aData[8], &pTrunk->aData[12], (k-1)*4);
+          releasePage(pNewTrunk);
+          if( !pPrevTrunk ){
+            assert( sqlite3PagerIswriteable(pPage1->pDbPage) );
+            put4byte(&pPage1->aData[32], iNewTrunk);
+          }else{
+            rc = sqlite3PagerWrite(pPrevTrunk->pDbPage);
+            if( rc ){
+              goto end_allocate_page;
+            }
+            put4byte(&pPrevTrunk->aData[0], iNewTrunk);
+          }
+        }
+        pTrunk = 0;
+        TRACE(("ALLOCATE: %u trunk - %u free pages left\n", *pPgno, n-1));
+#endif
+      }else if( k>0 ){
+        /* Extract a leaf from the trunk */
+        u32 closest;
+        Pgno iPage;
+        unsigned char *aData = pTrunk->aData;
+        if( nearby>0 ){
+          u32 i;
+          closest = 0;
+          if( eMode==BTALLOC_LE ){
+            for(i=0; i<k; i++){
+              iPage = get4byte(&aData[8+i*4]);
+              if( iPage<=nearby ){
+                closest = i;
+                break;
+              }
+            }
+          }else{
+            int dist;
+            dist = sqlite3AbsInt32(get4byte(&aData[8]) - nearby);
+            for(i=1; i<k; i++){
+              int d2 = sqlite3AbsInt32(get4byte(&aData[8+i*4]) - nearby);
+              if( d2<dist ){
+                closest = i;
+                dist = d2;
+              }
+            }
+          }
+        }else{
+          closest = 0;
+        }
+
+        iPage = get4byte(&aData[8+closest*4]);
+        testcase( iPage==mxPage );
+        if( iPage>mxPage || iPage<2 ){
+          rc = SQLITE_CORRUPT_PGNO(iTrunk);
+          goto end_allocate_page;
+        }
+        testcase( iPage==mxPage );
+        if( !searchList
+         || (iPage==nearby || (iPage<nearby && eMode==BTALLOC_LE))
+        ){
+          int noContent;
+          *pPgno = iPage;
+          TRACE(("ALLOCATE: %u was leaf %u of %u on trunk %u"
+                 ": %u more free pages\n",
+                 *pPgno, closest+1, k, pTrunk->pgno, n-1));
+          rc = sqlite3PagerWrite(pTrunk->pDbPage);
+          if( rc ) goto end_allocate_page;
+          if( closest<k-1 ){
+            memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
+          }
+          put4byte(&aData[4], k-1);
+          noContent = !btreeGetHasContent(pBt, *pPgno)? PAGER_GET_NOCONTENT : 0;
+          rc = btreeGetUnusedPage(pBt, *pPgno, ppPage, noContent);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3PagerWrite((*ppPage)->pDbPage);
+            if( rc!=SQLITE_OK ){
+              releasePage(*ppPage);
+              *ppPage = 0;
+            }
+          }
+          searchList = 0;
+        }
+      }
+      releasePage(pPrevTrunk);
+      pPrevTrunk = 0;
+    }while( searchList );
+  }else{
+    /* There are no pages on the freelist, so append a new page to the
+    ** database image.
+    **
+    ** Normally, new pages allocated by this block can be requested from the
+    ** pager layer with the 'no-content' flag set. This prevents the pager
+    ** from trying to read the pages content from disk. However, if the
+    ** current transaction has already run one or more incremental-vacuum
+    ** steps, then the page we are about to allocate may contain content
+    ** that is required in the event of a rollback. In this case, do
+    ** not set the no-content flag. This causes the pager to load and journal
+    ** the current page content before overwriting it.
+    **
+    ** Note that the pager will not actually attempt to load or journal
+    ** content for any page that really does lie past the end of the database
+    ** file on disk. So the effects of disabling the no-content optimization
+    ** here are confined to those pages that lie between the end of the
+    ** database image and the end of the database file.
+    */
+    int bNoContent = (0==IfNotOmitAV(pBt->bDoTruncate))? PAGER_GET_NOCONTENT:0;
+
+    rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+    if( rc ) return rc;
+    pBt->nPage++;
+    if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ) pBt->nPage++;
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum && PTRMAP_ISPAGE(pBt, pBt->nPage) ){
+      /* If *pPgno refers to a pointer-map page, allocate two new pages
+      ** at the end of the file instead of one. The first allocated page
+      ** becomes a new pointer-map page, the second is used by the caller.
+      */
+      MemPage *pPg = 0;
+      TRACE(("ALLOCATE: %u from end of file (pointer-map page)\n", pBt->nPage));
+      assert( pBt->nPage!=PENDING_BYTE_PAGE(pBt) );
+      rc = btreeGetUnusedPage(pBt, pBt->nPage, &pPg, bNoContent);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pPg->pDbPage);
+        releasePage(pPg);
+      }
+      if( rc ) return rc;
+      pBt->nPage++;
+      if( pBt->nPage==PENDING_BYTE_PAGE(pBt) ){ pBt->nPage++; }
+    }
+#endif
+    put4byte(28 + (u8*)pBt->pPage1->aData, pBt->nPage);
+    *pPgno = pBt->nPage;
+
+    assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
+    rc = btreeGetUnusedPage(pBt, *pPgno, ppPage, bNoContent);
+    if( rc ) return rc;
+    rc = sqlite3PagerWrite((*ppPage)->pDbPage);
+    if( rc!=SQLITE_OK ){
+      releasePage(*ppPage);
+      *ppPage = 0;
+    }
+    TRACE(("ALLOCATE: %u from end of file\n", *pPgno));
+  }
+
+  assert( CORRUPT_DB || *pPgno!=PENDING_BYTE_PAGE(pBt) );
+
+end_allocate_page:
+  releasePage(pTrunk);
+  releasePage(pPrevTrunk);
+  assert( rc!=SQLITE_OK || sqlite3PagerPageRefcount((*ppPage)->pDbPage)<=1 );
+  assert( rc!=SQLITE_OK || (*ppPage)->isInit==0 );
+  return rc;
+}
+
+/*
+** This function is used to add page iPage to the database file free-list.
+** It is assumed that the page is not already a part of the free-list.
+**
+** The value passed as the second argument to this function is optional.
+** If the caller happens to have a pointer to the MemPage object
+** corresponding to page iPage handy, it may pass it as the second value.
+** Otherwise, it may pass NULL.
+**
+** If a pointer to a MemPage object is passed as the second argument,
+** its reference count is not altered by this function.
+*/
+static int freePage2(BtShared *pBt, MemPage *pMemPage, Pgno iPage){
+  MemPage *pTrunk = 0;                /* Free-list trunk page */
+  Pgno iTrunk = 0;                    /* Page number of free-list trunk page */
+  MemPage *pPage1 = pBt->pPage1;      /* Local reference to page 1 */
+  MemPage *pPage;                     /* Page being freed. May be NULL. */
+  int rc;                             /* Return Code */
+  u32 nFree;                          /* Initial number of pages on free-list */
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( CORRUPT_DB || iPage>1 );
+  assert( !pMemPage || pMemPage->pgno==iPage );
+
+  if( iPage<2 || iPage>pBt->nPage ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( pMemPage ){
+    pPage = pMemPage;
+    sqlite3PagerRef(pPage->pDbPage);
+  }else{
+    pPage = btreePageLookup(pBt, iPage);
+  }
+
+  /* Increment the free page count on pPage1 */
+  rc = sqlite3PagerWrite(pPage1->pDbPage);
+  if( rc ) goto freepage_out;
+  nFree = get4byte(&pPage1->aData[36]);
+  put4byte(&pPage1->aData[36], nFree+1);
+
+  if( pBt->btsFlags & BTS_SECURE_DELETE ){
+    /* If the secure_delete option is enabled, then
+    ** always fully overwrite deleted information with zeros.
+    */
+    if( (!pPage && ((rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0) )
+     ||            ((rc = sqlite3PagerWrite(pPage->pDbPage))!=0)
+    ){
+      goto freepage_out;
+    }
+    memset(pPage->aData, 0, pPage->pBt->pageSize);
+  }
+
+  /* If the database supports auto-vacuum, write an entry in the pointer-map
+  ** to indicate that the page is free.
+  */
+  if( ISAUTOVACUUM(pBt) ){
+    ptrmapPut(pBt, iPage, PTRMAP_FREEPAGE, 0, &rc);
+    if( rc ) goto freepage_out;
+  }
+
+  /* Now manipulate the actual database free-list structure. There are two
+  ** possibilities. If the free-list is currently empty, or if the first
+  ** trunk page in the free-list is full, then this page will become a
+  ** new free-list trunk page. Otherwise, it will become a leaf of the
+  ** first trunk page in the current free-list. This block tests if it
+  ** is possible to add the page as a new free-list leaf.
+  */
+  if( nFree!=0 ){
+    u32 nLeaf;                /* Initial number of leaf cells on trunk page */
+
+    iTrunk = get4byte(&pPage1->aData[32]);
+    if( iTrunk>btreePagecount(pBt) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto freepage_out;
+    }
+    rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
+    if( rc!=SQLITE_OK ){
+      goto freepage_out;
+    }
+
+    nLeaf = get4byte(&pTrunk->aData[4]);
+    assert( pBt->usableSize>32 );
+    if( nLeaf > (u32)pBt->usableSize/4 - 2 ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto freepage_out;
+    }
+    if( nLeaf < (u32)pBt->usableSize/4 - 8 ){
+      /* In this case there is room on the trunk page to insert the page
+      ** being freed as a new leaf.
+      **
+      ** Note that the trunk page is not really full until it contains
+      ** usableSize/4 - 2 entries, not usableSize/4 - 8 entries as we have
+      ** coded.  But due to a coding error in versions of SQLite prior to
+      ** 3.6.0, databases with freelist trunk pages holding more than
+      ** usableSize/4 - 8 entries will be reported as corrupt.  In order
+      ** to maintain backwards compatibility with older versions of SQLite,
+      ** we will continue to restrict the number of entries to usableSize/4 - 8
+      ** for now.  At some point in the future (once everyone has upgraded
+      ** to 3.6.0 or later) we should consider fixing the conditional above
+      ** to read "usableSize/4-2" instead of "usableSize/4-8".
+      **
+      ** EVIDENCE-OF: R-19920-11576 However, newer versions of SQLite still
+      ** avoid using the last six entries in the freelist trunk page array in
+      ** order that database files created by newer versions of SQLite can be
+      ** read by older versions of SQLite.
+      */
+      rc = sqlite3PagerWrite(pTrunk->pDbPage);
+      if( rc==SQLITE_OK ){
+        put4byte(&pTrunk->aData[4], nLeaf+1);
+        put4byte(&pTrunk->aData[8+nLeaf*4], iPage);
+        if( pPage && (pBt->btsFlags & BTS_SECURE_DELETE)==0 ){
+          sqlite3PagerDontWrite(pPage->pDbPage);
+        }
+        rc = btreeSetHasContent(pBt, iPage);
+      }
+      TRACE(("FREE-PAGE: %u leaf on trunk page %u\n",pPage->pgno,pTrunk->pgno));
+      goto freepage_out;
+    }
+  }
+
+  /* If control flows to this point, then it was not possible to add the
+  ** the page being freed as a leaf page of the first trunk in the free-list.
+  ** Possibly because the free-list is empty, or possibly because the
+  ** first trunk in the free-list is full. Either way, the page being freed
+  ** will become the new first trunk page in the free-list.
+  */
+  if( pPage==0 && SQLITE_OK!=(rc = btreeGetPage(pBt, iPage, &pPage, 0)) ){
+    goto freepage_out;
+  }
+  rc = sqlite3PagerWrite(pPage->pDbPage);
+  if( rc!=SQLITE_OK ){
+    goto freepage_out;
+  }
+  put4byte(pPage->aData, iTrunk);
+  put4byte(&pPage->aData[4], 0);
+  put4byte(&pPage1->aData[32], iPage);
+  TRACE(("FREE-PAGE: %u new trunk page replacing %u\n", pPage->pgno, iTrunk));
+
+freepage_out:
+  if( pPage ){
+    pPage->isInit = 0;
+  }
+  releasePage(pPage);
+  releasePage(pTrunk);
+  return rc;
+}
+static void freePage(MemPage *pPage, int *pRC){
+  if( (*pRC)==SQLITE_OK ){
+    *pRC = freePage2(pPage->pBt, pPage, pPage->pgno);
+  }
+}
+
+/*
+** Free the overflow pages associated with the given Cell.
+*/
+static SQLITE_NOINLINE int clearCellOverflow(
+  MemPage *pPage,          /* The page that contains the Cell */
+  unsigned char *pCell,    /* First byte of the Cell */
+  CellInfo *pInfo          /* Size information about the cell */
+){
+  BtShared *pBt;
+  Pgno ovflPgno;
+  int rc;
+  int nOvfl;
+  u32 ovflPageSize;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pInfo->nLocal!=pInfo->nPayload );
+  testcase( pCell + pInfo->nSize == pPage->aDataEnd );
+  testcase( pCell + (pInfo->nSize-1) == pPage->aDataEnd );
+  if( pCell + pInfo->nSize > pPage->aDataEnd ){
+    /* Cell extends past end of page */
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  ovflPgno = get4byte(pCell + pInfo->nSize - 4);
+  pBt = pPage->pBt;
+  assert( pBt->usableSize > 4 );
+  ovflPageSize = pBt->usableSize - 4;
+  nOvfl = (pInfo->nPayload - pInfo->nLocal + ovflPageSize - 1)/ovflPageSize;
+  assert( nOvfl>0 ||
+    (CORRUPT_DB && (pInfo->nPayload + ovflPageSize)<ovflPageSize)
+  );
+  while( nOvfl-- ){
+    Pgno iNext = 0;
+    MemPage *pOvfl = 0;
+    if( ovflPgno<2 || ovflPgno>btreePagecount(pBt) ){
+      /* 0 is not a legal page number and page 1 cannot be an
+      ** overflow page. Therefore if ovflPgno<2 or past the end of the
+      ** file the database must be corrupt. */
+      return SQLITE_CORRUPT_BKPT;
+    }
+    if( nOvfl ){
+      rc = getOverflowPage(pBt, ovflPgno, &pOvfl, &iNext);
+      if( rc ) return rc;
+    }
+
+    if( ( pOvfl || ((pOvfl = btreePageLookup(pBt, ovflPgno))!=0) )
+     && sqlite3PagerPageRefcount(pOvfl->pDbPage)!=1
+    ){
+      /* There is no reason any cursor should have an outstanding reference
+      ** to an overflow page belonging to a cell that is being deleted/updated.
+      ** So if there exists more than one reference to this page, then it
+      ** must not really be an overflow page and the database must be corrupt.
+      ** It is helpful to detect this before calling freePage2(), as
+      ** freePage2() may zero the page contents if secure-delete mode is
+      ** enabled. If this 'overflow' page happens to be a page that the
+      ** caller is iterating through or using in some other way, this
+      ** can be problematic.
+      */
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      rc = freePage2(pBt, pOvfl, ovflPgno);
+    }
+
+    if( pOvfl ){
+      sqlite3PagerUnref(pOvfl->pDbPage);
+    }
+    if( rc ) return rc;
+    ovflPgno = iNext;
+  }
+  return SQLITE_OK;
+}
+
+/* Call xParseCell to compute the size of a cell.  If the cell contains
+** overflow, then invoke cellClearOverflow to clear out that overflow.
+** Store the result code (SQLITE_OK or some error code) in rc.
+**
+** Implemented as macro to force inlining for performance.
+*/
+#define BTREE_CLEAR_CELL(rc, pPage, pCell, sInfo)   \
+  pPage->xParseCell(pPage, pCell, &sInfo);          \
+  if( sInfo.nLocal!=sInfo.nPayload ){               \
+    rc = clearCellOverflow(pPage, pCell, &sInfo);   \
+  }else{                                            \
+    rc = SQLITE_OK;                                 \
+  }
+
+
+/*
+** Create the byte sequence used to represent a cell on page pPage
+** and write that byte sequence into pCell[].  Overflow pages are
+** allocated and filled in as necessary.  The calling procedure
+** is responsible for making sure sufficient space has been allocated
+** for pCell[].
+**
+** Note that pCell does not necessary need to point to the pPage->aData
+** area.  pCell might point to some temporary storage.  The cell will
+** be constructed in this temporary area then copied into pPage->aData
+** later.
+*/
+static int fillInCell(
+  MemPage *pPage,                /* The page that contains the cell */
+  unsigned char *pCell,          /* Complete text of the cell */
+  const BtreePayload *pX,        /* Payload with which to construct the cell */
+  int *pnSize                    /* Write cell size here */
+){
+  int nPayload;
+  const u8 *pSrc;
+  int nSrc, n, rc, mn;
+  int spaceLeft;
+  MemPage *pToRelease;
+  unsigned char *pPrior;
+  unsigned char *pPayload;
+  BtShared *pBt;
+  Pgno pgnoOvfl;
+  int nHeader;
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+
+  /* pPage is not necessarily writeable since pCell might be auxiliary
+  ** buffer space that is separate from the pPage buffer area */
+  assert( pCell<pPage->aData || pCell>=&pPage->aData[pPage->pBt->pageSize]
+            || sqlite3PagerIswriteable(pPage->pDbPage) );
+
+  /* Fill in the header. */
+  nHeader = pPage->childPtrSize;
+  if( pPage->intKey ){
+    nPayload = pX->nData + pX->nZero;
+    pSrc = pX->pData;
+    nSrc = pX->nData;
+    assert( pPage->intKeyLeaf ); /* fillInCell() only called for leaves */
+    nHeader += putVarint32(&pCell[nHeader], nPayload);
+    nHeader += putVarint(&pCell[nHeader], *(u64*)&pX->nKey);
+  }else{
+    assert( pX->nKey<=0x7fffffff && pX->pKey!=0 );
+    nSrc = nPayload = (int)pX->nKey;
+    pSrc = pX->pKey;
+    nHeader += putVarint32(&pCell[nHeader], nPayload);
+  }
+
+  /* Fill in the payload */
+  pPayload = &pCell[nHeader];
+  if( nPayload<=pPage->maxLocal ){
+    /* This is the common case where everything fits on the btree page
+    ** and no overflow pages are required. */
+    n = nHeader + nPayload;
+    testcase( n==3 );
+    testcase( n==4 );
+    if( n<4 ){
+      n = 4;
+      pPayload[nPayload] = 0;
+    }
+    *pnSize = n;
+    assert( nSrc<=nPayload );
+    testcase( nSrc<nPayload );
+    memcpy(pPayload, pSrc, nSrc);
+    memset(pPayload+nSrc, 0, nPayload-nSrc);
+    return SQLITE_OK;
+  }
+
+  /* If we reach this point, it means that some of the content will need
+  ** to spill onto overflow pages.
+  */
+  mn = pPage->minLocal;
+  n = mn + (nPayload - mn) % (pPage->pBt->usableSize - 4);
+  testcase( n==pPage->maxLocal );
+  testcase( n==pPage->maxLocal+1 );
+  if( n > pPage->maxLocal ) n = mn;
+  spaceLeft = n;
+  *pnSize = n + nHeader + 4;
+  pPrior = &pCell[nHeader+n];
+  pToRelease = 0;
+  pgnoOvfl = 0;
+  pBt = pPage->pBt;
+
+  /* At this point variables should be set as follows:
+  **
+  **   nPayload           Total payload size in bytes
+  **   pPayload           Begin writing payload here
+  **   spaceLeft          Space available at pPayload.  If nPayload>spaceLeft,
+  **                      that means content must spill into overflow pages.
+  **   *pnSize            Size of the local cell (not counting overflow pages)
+  **   pPrior             Where to write the pgno of the first overflow page
+  **
+  ** Use a call to btreeParseCellPtr() to verify that the values above
+  ** were computed correctly.
+  */
+#ifdef SQLITE_DEBUG
+  {
+    CellInfo info;
+    pPage->xParseCell(pPage, pCell, &info);
+    assert( nHeader==(int)(info.pPayload - pCell) );
+    assert( info.nKey==pX->nKey );
+    assert( *pnSize == info.nSize );
+    assert( spaceLeft == info.nLocal );
+  }
+#endif
+
+  /* Write the payload into the local Cell and any extra into overflow pages */
+  while( 1 ){
+    n = nPayload;
+    if( n>spaceLeft ) n = spaceLeft;
+
+    /* If pToRelease is not zero than pPayload points into the data area
+    ** of pToRelease.  Make sure pToRelease is still writeable. */
+    assert( pToRelease==0 || sqlite3PagerIswriteable(pToRelease->pDbPage) );
+
+    /* If pPayload is part of the data area of pPage, then make sure pPage
+    ** is still writeable */
+    assert( pPayload<pPage->aData || pPayload>=&pPage->aData[pBt->pageSize]
+            || sqlite3PagerIswriteable(pPage->pDbPage) );
+
+    if( nSrc>=n ){
+      memcpy(pPayload, pSrc, n);
+    }else if( nSrc>0 ){
+      n = nSrc;
+      memcpy(pPayload, pSrc, n);
+    }else{
+      memset(pPayload, 0, n);
+    }
+    nPayload -= n;
+    if( nPayload<=0 ) break;
+    pPayload += n;
+    pSrc += n;
+    nSrc -= n;
+    spaceLeft -= n;
+    if( spaceLeft==0 ){
+      MemPage *pOvfl = 0;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      Pgno pgnoPtrmap = pgnoOvfl; /* Overflow page pointer-map entry page */
+      if( pBt->autoVacuum ){
+        do{
+          pgnoOvfl++;
+        } while(
+          PTRMAP_ISPAGE(pBt, pgnoOvfl) || pgnoOvfl==PENDING_BYTE_PAGE(pBt)
+        );
+      }
+#endif
+      rc = allocateBtreePage(pBt, &pOvfl, &pgnoOvfl, pgnoOvfl, 0);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      /* If the database supports auto-vacuum, and the second or subsequent
+      ** overflow page is being allocated, add an entry to the pointer-map
+      ** for that page now.
+      **
+      ** If this is the first overflow page, then write a partial entry
+      ** to the pointer-map. If we write nothing to this pointer-map slot,
+      ** then the optimistic overflow chain processing in clearCell()
+      ** may misinterpret the uninitialized values and delete the
+      ** wrong pages from the database.
+      */
+      if( pBt->autoVacuum && rc==SQLITE_OK ){
+        u8 eType = (pgnoPtrmap?PTRMAP_OVERFLOW2:PTRMAP_OVERFLOW1);
+        ptrmapPut(pBt, pgnoOvfl, eType, pgnoPtrmap, &rc);
+        if( rc ){
+          releasePage(pOvfl);
+        }
+      }
+#endif
+      if( rc ){
+        releasePage(pToRelease);
+        return rc;
+      }
+
+      /* If pToRelease is not zero than pPrior points into the data area
+      ** of pToRelease.  Make sure pToRelease is still writeable. */
+      assert( pToRelease==0 || sqlite3PagerIswriteable(pToRelease->pDbPage) );
+
+      /* If pPrior is part of the data area of pPage, then make sure pPage
+      ** is still writeable */
+      assert( pPrior<pPage->aData || pPrior>=&pPage->aData[pBt->pageSize]
+            || sqlite3PagerIswriteable(pPage->pDbPage) );
+
+      put4byte(pPrior, pgnoOvfl);
+      releasePage(pToRelease);
+      pToRelease = pOvfl;
+      pPrior = pOvfl->aData;
+      put4byte(pPrior, 0);
+      pPayload = &pOvfl->aData[4];
+      spaceLeft = pBt->usableSize - 4;
+    }
+  }
+  releasePage(pToRelease);
+  return SQLITE_OK;
+}
+
+/*
+** Remove the i-th cell from pPage.  This routine effects pPage only.
+** The cell content is not freed or deallocated.  It is assumed that
+** the cell content has been copied someplace else.  This routine just
+** removes the reference to the cell from pPage.
+**
+** "sz" must be the number of bytes in the cell.
+*/
+static void dropCell(MemPage *pPage, int idx, int sz, int *pRC){
+  u32 pc;         /* Offset to cell content of cell being deleted */
+  u8 *data;       /* pPage->aData */
+  u8 *ptr;        /* Used to move bytes around within data[] */
+  int rc;         /* The return code */
+  int hdr;        /* Beginning of the header.  0 most pages.  100 page 1 */
+
+  if( *pRC ) return;
+  assert( idx>=0 );
+  assert( idx<pPage->nCell );
+  assert( CORRUPT_DB || sz==cellSize(pPage, idx) );
+  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( pPage->nFree>=0 );
+  data = pPage->aData;
+  ptr = &pPage->aCellIdx[2*idx];
+  assert( pPage->pBt->usableSize > (u32)(ptr-data) );
+  pc = get2byte(ptr);
+  hdr = pPage->hdrOffset;
+  testcase( pc==(u32)get2byte(&data[hdr+5]) );
+  testcase( pc+sz==pPage->pBt->usableSize );
+  if( pc+sz > pPage->pBt->usableSize ){
+    *pRC = SQLITE_CORRUPT_BKPT;
+    return;
+  }
+  rc = freeSpace(pPage, pc, sz);
+  if( rc ){
+    *pRC = rc;
+    return;
+  }
+  pPage->nCell--;
+  if( pPage->nCell==0 ){
+    memset(&data[hdr+1], 0, 4);
+    data[hdr+7] = 0;
+    put2byte(&data[hdr+5], pPage->pBt->usableSize);
+    pPage->nFree = pPage->pBt->usableSize - pPage->hdrOffset
+                       - pPage->childPtrSize - 8;
+  }else{
+    memmove(ptr, ptr+2, 2*(pPage->nCell - idx));
+    put2byte(&data[hdr+3], pPage->nCell);
+    pPage->nFree += 2;
+  }
+}
+
+/*
+** Insert a new cell on pPage at cell index "i".  pCell points to the
+** content of the cell.
+**
+** If the cell content will fit on the page, then put it there.  If it
+** will not fit, then make a copy of the cell content into pTemp if
+** pTemp is not null.  Regardless of pTemp, allocate a new entry
+** in pPage->apOvfl[] and make it point to the cell content (either
+** in pTemp or the original pCell) and also record its index.
+** Allocating a new entry in pPage->aCell[] implies that
+** pPage->nOverflow is incremented.
+**
+** The insertCellFast() routine below works exactly the same as
+** insertCell() except that it lacks the pTemp and iChild parameters
+** which are assumed zero.  Other than that, the two routines are the
+** same.
+**
+** Fixes or enhancements to this routine should be reflected in
+** insertCellFast()!
+*/
+static int insertCell(
+  MemPage *pPage,   /* Page into which we are copying */
+  int i,            /* New cell becomes the i-th cell of the page */
+  u8 *pCell,        /* Content of the new cell */
+  int sz,           /* Bytes of content in pCell */
+  u8 *pTemp,        /* Temp storage space for pCell, if needed */
+  Pgno iChild       /* If non-zero, replace first 4 bytes with this value */
+){
+  int idx = 0;      /* Where to write new cell content in data[] */
+  int j;            /* Loop counter */
+  u8 *data;         /* The content of the whole page */
+  u8 *pIns;         /* The point in pPage->aCellIdx[] where no cell inserted */
+
+  assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
+  assert( MX_CELL(pPage->pBt)<=10921 );
+  assert( pPage->nCell<=MX_CELL(pPage->pBt) || CORRUPT_DB );
+  assert( pPage->nOverflow<=ArraySize(pPage->apOvfl) );
+  assert( ArraySize(pPage->apOvfl)==ArraySize(pPage->aiOvfl) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( sz==pPage->xCellSize(pPage, pCell) || CORRUPT_DB );
+  assert( pPage->nFree>=0 );
+  assert( iChild>0 );
+  if( pPage->nOverflow || sz+2>pPage->nFree ){
+    if( pTemp ){
+      memcpy(pTemp, pCell, sz);
+      pCell = pTemp;
+    }
+    put4byte(pCell, iChild);
+    j = pPage->nOverflow++;
+    /* Comparison against ArraySize-1 since we hold back one extra slot
+    ** as a contingency.  In other words, never need more than 3 overflow
+    ** slots but 4 are allocated, just to be safe. */
+    assert( j < ArraySize(pPage->apOvfl)-1 );
+    pPage->apOvfl[j] = pCell;
+    pPage->aiOvfl[j] = (u16)i;
+
+    /* When multiple overflows occur, they are always sequential and in
+    ** sorted order.  This invariants arise because multiple overflows can
+    ** only occur when inserting divider cells into the parent page during
+    ** balancing, and the dividers are adjacent and sorted.
+    */
+    assert( j==0 || pPage->aiOvfl[j-1]<(u16)i ); /* Overflows in sorted order */
+    assert( j==0 || i==pPage->aiOvfl[j-1]+1 );   /* Overflows are sequential */
+  }else{
+    int rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( NEVER(rc!=SQLITE_OK) ){
+      return rc;
+    }
+    assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+    data = pPage->aData;
+    assert( &data[pPage->cellOffset]==pPage->aCellIdx );
+    rc = allocateSpace(pPage, sz, &idx);
+    if( rc ){ return rc; }
+    /* The allocateSpace() routine guarantees the following properties
+    ** if it returns successfully */
+    assert( idx >= 0 );
+    assert( idx >= pPage->cellOffset+2*pPage->nCell+2 || CORRUPT_DB );
+    assert( idx+sz <= (int)pPage->pBt->usableSize );
+    pPage->nFree -= (u16)(2 + sz);
+    /* In a corrupt database where an entry in the cell index section of
+    ** a btree page has a value of 3 or less, the pCell value might point
+    ** as many as 4 bytes in front of the start of the aData buffer for
+    ** the source page.  Make sure this does not cause problems by not
+    ** reading the first 4 bytes */
+    memcpy(&data[idx+4], pCell+4, sz-4);
+    put4byte(&data[idx], iChild);
+    pIns = pPage->aCellIdx + i*2;
+    memmove(pIns+2, pIns, 2*(pPage->nCell - i));
+    put2byte(pIns, idx);
+    pPage->nCell++;
+    /* increment the cell count */
+    if( (++data[pPage->hdrOffset+4])==0 ) data[pPage->hdrOffset+3]++;
+    assert( get2byte(&data[pPage->hdrOffset+3])==pPage->nCell || CORRUPT_DB );
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pPage->pBt->autoVacuum ){
+      int rc2 = SQLITE_OK;
+      /* The cell may contain a pointer to an overflow page. If so, write
+      ** the entry for the overflow page into the pointer map.
+      */
+      ptrmapPutOvflPtr(pPage, pPage, pCell, &rc2);
+      if( rc2 ) return rc2;
+    }
+#endif
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This variant of insertCell() assumes that the pTemp and iChild
+** parameters are both zero.  Use this variant in sqlite3BtreeInsert()
+** for performance improvement, and also so that this variant is only
+** called from that one place, and is thus inlined, and thus runs must
+** faster.
+**
+** Fixes or enhancements to this routine should be reflected into
+** the insertCell() routine.
+*/
+static int insertCellFast(
+  MemPage *pPage,   /* Page into which we are copying */
+  int i,            /* New cell becomes the i-th cell of the page */
+  u8 *pCell,        /* Content of the new cell */
+  int sz            /* Bytes of content in pCell */
+){
+  int idx = 0;      /* Where to write new cell content in data[] */
+  int j;            /* Loop counter */
+  u8 *data;         /* The content of the whole page */
+  u8 *pIns;         /* The point in pPage->aCellIdx[] where no cell inserted */
+
+  assert( i>=0 && i<=pPage->nCell+pPage->nOverflow );
+  assert( MX_CELL(pPage->pBt)<=10921 );
+  assert( pPage->nCell<=MX_CELL(pPage->pBt) || CORRUPT_DB );
+  assert( pPage->nOverflow<=ArraySize(pPage->apOvfl) );
+  assert( ArraySize(pPage->apOvfl)==ArraySize(pPage->aiOvfl) );
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( sz==pPage->xCellSize(pPage, pCell) || CORRUPT_DB );
+  assert( pPage->nFree>=0 );
+  assert( pPage->nOverflow==0 );
+  if( sz+2>pPage->nFree ){
+    j = pPage->nOverflow++;
+    /* Comparison against ArraySize-1 since we hold back one extra slot
+    ** as a contingency.  In other words, never need more than 3 overflow
+    ** slots but 4 are allocated, just to be safe. */
+    assert( j < ArraySize(pPage->apOvfl)-1 );
+    pPage->apOvfl[j] = pCell;
+    pPage->aiOvfl[j] = (u16)i;
+
+    /* When multiple overflows occur, they are always sequential and in
+    ** sorted order.  This invariants arise because multiple overflows can
+    ** only occur when inserting divider cells into the parent page during
+    ** balancing, and the dividers are adjacent and sorted.
+    */
+    assert( j==0 || pPage->aiOvfl[j-1]<(u16)i ); /* Overflows in sorted order */
+    assert( j==0 || i==pPage->aiOvfl[j-1]+1 );   /* Overflows are sequential */
+  }else{
+    int rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    assert( sqlite3PagerIswriteable(pPage->pDbPage) );
+    data = pPage->aData;
+    assert( &data[pPage->cellOffset]==pPage->aCellIdx );
+    rc = allocateSpace(pPage, sz, &idx);
+    if( rc ){ return rc; }
+    /* The allocateSpace() routine guarantees the following properties
+    ** if it returns successfully */
+    assert( idx >= 0 );
+    assert( idx >= pPage->cellOffset+2*pPage->nCell+2 || CORRUPT_DB );
+    assert( idx+sz <= (int)pPage->pBt->usableSize );
+    pPage->nFree -= (u16)(2 + sz);
+    memcpy(&data[idx], pCell, sz);
+    pIns = pPage->aCellIdx + i*2;
+    memmove(pIns+2, pIns, 2*(pPage->nCell - i));
+    put2byte(pIns, idx);
+    pPage->nCell++;
+    /* increment the cell count */
+    if( (++data[pPage->hdrOffset+4])==0 ) data[pPage->hdrOffset+3]++;
+    assert( get2byte(&data[pPage->hdrOffset+3])==pPage->nCell || CORRUPT_DB );
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pPage->pBt->autoVacuum ){
+      int rc2 = SQLITE_OK;
+      /* The cell may contain a pointer to an overflow page. If so, write
+      ** the entry for the overflow page into the pointer map.
+      */
+      ptrmapPutOvflPtr(pPage, pPage, pCell, &rc2);
+      if( rc2 ) return rc2;
+    }
+#endif
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The following parameters determine how many adjacent pages get involved
+** in a balancing operation.  NN is the number of neighbors on either side
+** of the page that participate in the balancing operation.  NB is the
+** total number of pages that participate, including the target page and
+** NN neighbors on either side.
+**
+** The minimum value of NN is 1 (of course).  Increasing NN above 1
+** (to 2 or 3) gives a modest improvement in SELECT and DELETE performance
+** in exchange for a larger degradation in INSERT and UPDATE performance.
+** The value of NN appears to give the best results overall.
+**
+** (Later:) The description above makes it seem as if these values are
+** tunable - as if you could change them and recompile and it would all work.
+** But that is unlikely.  NB has been 3 since the inception of SQLite and
+** we have never tested any other value.
+*/
+#define NN 1             /* Number of neighbors on either side of pPage */
+#define NB 3             /* (NN*2+1): Total pages involved in the balance */
+
+/*
+** A CellArray object contains a cache of pointers and sizes for a
+** consecutive sequence of cells that might be held on multiple pages.
+**
+** The cells in this array are the divider cell or cells from the pParent
+** page plus up to three child pages.  There are a total of nCell cells.
+**
+** pRef is a pointer to one of the pages that contributes cells.  This is
+** used to access information such as MemPage.intKey and MemPage.pBt->pageSize
+** which should be common to all pages that contribute cells to this array.
+**
+** apCell[] and szCell[] hold, respectively, pointers to the start of each
+** cell and the size of each cell.  Some of the apCell[] pointers might refer
+** to overflow cells.  In other words, some apCel[] pointers might not point
+** to content area of the pages.
+**
+** A szCell[] of zero means the size of that cell has not yet been computed.
+**
+** The cells come from as many as four different pages:
+**
+**             -----------
+**             | Parent  |
+**             -----------
+**            /     |     \
+**           /      |      \
+**  ---------   ---------   ---------
+**  |Child-1|   |Child-2|   |Child-3|
+**  ---------   ---------   ---------
+**
+** The order of cells is in the array is for an index btree is:
+**
+**       1.  All cells from Child-1 in order
+**       2.  The first divider cell from Parent
+**       3.  All cells from Child-2 in order
+**       4.  The second divider cell from Parent
+**       5.  All cells from Child-3 in order
+**
+** For a table-btree (with rowids) the items 2 and 4 are empty because
+** content exists only in leaves and there are no divider cells.
+**
+** For an index btree, the apEnd[] array holds pointer to the end of page
+** for Child-1, the Parent, Child-2, the Parent (again), and Child-3,
+** respectively. The ixNx[] array holds the number of cells contained in
+** each of these 5 stages, and all stages to the left.  Hence:
+**
+**    ixNx[0] = Number of cells in Child-1.
+**    ixNx[1] = Number of cells in Child-1 plus 1 for first divider.
+**    ixNx[2] = Number of cells in Child-1 and Child-2 + 1 for 1st divider.
+**    ixNx[3] = Number of cells in Child-1 and Child-2 + both divider cells
+**    ixNx[4] = Total number of cells.
+**
+** For a table-btree, the concept is similar, except only apEnd[0]..apEnd[2]
+** are used and they point to the leaf pages only, and the ixNx value are:
+**
+**    ixNx[0] = Number of cells in Child-1.
+**    ixNx[1] = Number of cells in Child-1 and Child-2.
+**    ixNx[2] = Total number of cells.
+**
+** Sometimes when deleting, a child page can have zero cells.  In those
+** cases, ixNx[] entries with higher indexes, and the corresponding apEnd[]
+** entries, shift down.  The end result is that each ixNx[] entry should
+** be larger than the previous
+*/
+typedef struct CellArray CellArray;
+struct CellArray {
+  int nCell;              /* Number of cells in apCell[] */
+  MemPage *pRef;          /* Reference page */
+  u8 **apCell;            /* All cells begin balanced */
+  u16 *szCell;            /* Local size of all cells in apCell[] */
+  u8 *apEnd[NB*2];        /* MemPage.aDataEnd values */
+  int ixNx[NB*2];         /* Index of at which we move to the next apEnd[] */
+};
+
+/*
+** Make sure the cell sizes at idx, idx+1, ..., idx+N-1 have been
+** computed.
+*/
+static void populateCellCache(CellArray *p, int idx, int N){
+  MemPage *pRef = p->pRef;
+  u16 *szCell = p->szCell;
+  assert( idx>=0 && idx+N<=p->nCell );
+  while( N>0 ){
+    assert( p->apCell[idx]!=0 );
+    if( szCell[idx]==0 ){
+      szCell[idx] = pRef->xCellSize(pRef, p->apCell[idx]);
+    }else{
+      assert( CORRUPT_DB ||
+              szCell[idx]==pRef->xCellSize(pRef, p->apCell[idx]) );
+    }
+    idx++;
+    N--;
+  }
+}
+
+/*
+** Return the size of the Nth element of the cell array
+*/
+static SQLITE_NOINLINE u16 computeCellSize(CellArray *p, int N){
+  assert( N>=0 && N<p->nCell );
+  assert( p->szCell[N]==0 );
+  p->szCell[N] = p->pRef->xCellSize(p->pRef, p->apCell[N]);
+  return p->szCell[N];
+}
+static u16 cachedCellSize(CellArray *p, int N){
+  assert( N>=0 && N<p->nCell );
+  if( p->szCell[N] ) return p->szCell[N];
+  return computeCellSize(p, N);
+}
+
+/*
+** Array apCell[] contains pointers to nCell b-tree page cells. The
+** szCell[] array contains the size in bytes of each cell. This function
+** replaces the current contents of page pPg with the contents of the cell
+** array.
+**
+** Some of the cells in apCell[] may currently be stored in pPg. This
+** function works around problems caused by this by making a copy of any
+** such cells before overwriting the page data.
+**
+** The MemPage.nFree field is invalidated by this function. It is the
+** responsibility of the caller to set it correctly.
+*/
+static int rebuildPage(
+  CellArray *pCArray,             /* Content to be added to page pPg */
+  int iFirst,                     /* First cell in pCArray to use */
+  int nCell,                      /* Final number of cells on page */
+  MemPage *pPg                    /* The page to be reconstructed */
+){
+  const int hdr = pPg->hdrOffset;          /* Offset of header on pPg */
+  u8 * const aData = pPg->aData;           /* Pointer to data for pPg */
+  const int usableSize = pPg->pBt->usableSize;
+  u8 * const pEnd = &aData[usableSize];
+  int i = iFirst;                 /* Which cell to copy from pCArray*/
+  u32 j;                          /* Start of cell content area */
+  int iEnd = i+nCell;             /* Loop terminator */
+  u8 *pCellptr = pPg->aCellIdx;
+  u8 *pTmp = sqlite3PagerTempSpace(pPg->pBt->pPager);
+  u8 *pData;
+  int k;                          /* Current slot in pCArray->apEnd[] */
+  u8 *pSrcEnd;                    /* Current pCArray->apEnd[k] value */
+
+  assert( nCell>0 );
+  assert( i<iEnd );
+  j = get2byte(&aData[hdr+5]);
+  if( j>(u32)usableSize ){ j = 0; }
+  memcpy(&pTmp[j], &aData[j], usableSize - j);
+
+  assert( pCArray->ixNx[NB*2-1]>i );
+  for(k=0; pCArray->ixNx[k]<=i; k++){}
+  pSrcEnd = pCArray->apEnd[k];
+
+  pData = pEnd;
+  while( 1/*exit by break*/ ){
+    u8 *pCell = pCArray->apCell[i];
+    u16 sz = pCArray->szCell[i];
+    assert( sz>0 );
+    if( SQLITE_WITHIN(pCell,aData+j,pEnd) ){
+      if( ((uptr)(pCell+sz))>(uptr)pEnd ) return SQLITE_CORRUPT_BKPT;
+      pCell = &pTmp[pCell - aData];
+    }else if( (uptr)(pCell+sz)>(uptr)pSrcEnd
+           && (uptr)(pCell)<(uptr)pSrcEnd
+    ){
+      return SQLITE_CORRUPT_BKPT;
+    }
+
+    pData -= sz;
+    put2byte(pCellptr, (pData - aData));
+    pCellptr += 2;
+    if( pData < pCellptr ) return SQLITE_CORRUPT_BKPT;
+    memmove(pData, pCell, sz);
+    assert( sz==pPg->xCellSize(pPg, pCell) || CORRUPT_DB );
+    i++;
+    if( i>=iEnd ) break;
+    if( pCArray->ixNx[k]<=i ){
+      k++;
+      pSrcEnd = pCArray->apEnd[k];
+    }
+  }
+
+  /* The pPg->nFree field is now set incorrectly. The caller will fix it. */
+  pPg->nCell = nCell;
+  pPg->nOverflow = 0;
+
+  put2byte(&aData[hdr+1], 0);
+  put2byte(&aData[hdr+3], pPg->nCell);
+  put2byte(&aData[hdr+5], pData - aData);
+  aData[hdr+7] = 0x00;
+  return SQLITE_OK;
+}
+
+/*
+** The pCArray objects contains pointers to b-tree cells and the cell sizes.
+** This function attempts to add the cells stored in the array to page pPg.
+** If it cannot (because the page needs to be defragmented before the cells
+** will fit), non-zero is returned. Otherwise, if the cells are added
+** successfully, zero is returned.
+**
+** Argument pCellptr points to the first entry in the cell-pointer array
+** (part of page pPg) to populate. After cell apCell[0] is written to the
+** page body, a 16-bit offset is written to pCellptr. And so on, for each
+** cell in the array. It is the responsibility of the caller to ensure
+** that it is safe to overwrite this part of the cell-pointer array.
+**
+** When this function is called, *ppData points to the start of the
+** content area on page pPg. If the size of the content area is extended,
+** *ppData is updated to point to the new start of the content area
+** before returning.
+**
+** Finally, argument pBegin points to the byte immediately following the
+** end of the space required by this page for the cell-pointer area (for
+** all cells - not just those inserted by the current call). If the content
+** area must be extended to before this point in order to accommodate all
+** cells in apCell[], then the cells do not fit and non-zero is returned.
+*/
+static int pageInsertArray(
+  MemPage *pPg,                   /* Page to add cells to */
+  u8 *pBegin,                     /* End of cell-pointer array */
+  u8 **ppData,                    /* IN/OUT: Page content-area pointer */
+  u8 *pCellptr,                   /* Pointer to cell-pointer area */
+  int iFirst,                     /* Index of first cell to add */
+  int nCell,                      /* Number of cells to add to pPg */
+  CellArray *pCArray              /* Array of cells */
+){
+  int i = iFirst;                 /* Loop counter - cell index to insert */
+  u8 *aData = pPg->aData;         /* Complete page */
+  u8 *pData = *ppData;            /* Content area.  A subset of aData[] */
+  int iEnd = iFirst + nCell;      /* End of loop. One past last cell to ins */
+  int k;                          /* Current slot in pCArray->apEnd[] */
+  u8 *pEnd;                       /* Maximum extent of cell data */
+  assert( CORRUPT_DB || pPg->hdrOffset==0 );    /* Never called on page 1 */
+  if( iEnd<=iFirst ) return 0;
+  assert( pCArray->ixNx[NB*2-1]>i );
+  for(k=0; pCArray->ixNx[k]<=i ; k++){}
+  pEnd = pCArray->apEnd[k];
+  while( 1 /*Exit by break*/ ){
+    int sz, rc;
+    u8 *pSlot;
+    assert( pCArray->szCell[i]!=0 );
+    sz = pCArray->szCell[i];
+    if( (aData[1]==0 && aData[2]==0) || (pSlot = pageFindSlot(pPg,sz,&rc))==0 ){
+      if( (pData - pBegin)<sz ) return 1;
+      pData -= sz;
+      pSlot = pData;
+    }
+    /* pSlot and pCArray->apCell[i] will never overlap on a well-formed
+    ** database.  But they might for a corrupt database.  Hence use memmove()
+    ** since memcpy() sends SIGABORT with overlapping buffers on OpenBSD */
+    assert( (pSlot+sz)<=pCArray->apCell[i]
+         || pSlot>=(pCArray->apCell[i]+sz)
+         || CORRUPT_DB );
+    if( (uptr)(pCArray->apCell[i]+sz)>(uptr)pEnd
+     && (uptr)(pCArray->apCell[i])<(uptr)pEnd
+    ){
+      assert( CORRUPT_DB );
+      (void)SQLITE_CORRUPT_BKPT;
+      return 1;
+    }
+    memmove(pSlot, pCArray->apCell[i], sz);
+    put2byte(pCellptr, (pSlot - aData));
+    pCellptr += 2;
+    i++;
+    if( i>=iEnd ) break;
+    if( pCArray->ixNx[k]<=i ){
+      k++;
+      pEnd = pCArray->apEnd[k];
+    }
+  }
+  *ppData = pData;
+  return 0;
+}
+
+/*
+** The pCArray object contains pointers to b-tree cells and their sizes.
+**
+** This function adds the space associated with each cell in the array
+** that is currently stored within the body of pPg to the pPg free-list.
+** The cell-pointers and other fields of the page are not updated.
+**
+** This function returns the total number of cells added to the free-list.
+*/
+static int pageFreeArray(
+  MemPage *pPg,                   /* Page to edit */
+  int iFirst,                     /* First cell to delete */
+  int nCell,                      /* Cells to delete */
+  CellArray *pCArray              /* Array of cells */
+){
+  u8 * const aData = pPg->aData;
+  u8 * const pEnd = &aData[pPg->pBt->usableSize];
+  u8 * const pStart = &aData[pPg->hdrOffset + 8 + pPg->childPtrSize];
+  int nRet = 0;
+  int i, j;
+  int iEnd = iFirst + nCell;
+  int nFree = 0;
+  int aOfst[10];
+  int aAfter[10];
+
+  for(i=iFirst; i<iEnd; i++){
+    u8 *pCell = pCArray->apCell[i];
+    if( SQLITE_WITHIN(pCell, pStart, pEnd) ){
+      int sz;
+      int iAfter;
+      int iOfst;
+      /* No need to use cachedCellSize() here.  The sizes of all cells that
+      ** are to be freed have already been computing while deciding which
+      ** cells need freeing */
+      sz = pCArray->szCell[i];  assert( sz>0 );
+      iOfst = (u16)(pCell - aData);
+      iAfter = iOfst+sz;
+      for(j=0; j<nFree; j++){
+        if( aOfst[j]==iAfter ){
+          aOfst[j] = iOfst;
+          break;
+        }else if( aAfter[j]==iOfst ){
+          aAfter[j] = iAfter;
+          break;
+        }
+      }
+      if( j>=nFree ){
+        if( nFree>=(int)(sizeof(aOfst)/sizeof(aOfst[0])) ){
+          for(j=0; j<nFree; j++){
+            freeSpace(pPg, aOfst[j], aAfter[j]-aOfst[j]);
+          }
+          nFree = 0;
+        }
+        aOfst[nFree] = iOfst;
+        aAfter[nFree] = iAfter;
+        if( &aData[iAfter]>pEnd ) return 0;
+        nFree++;
+      }
+      nRet++;
+    }
+  }
+  for(j=0; j<nFree; j++){
+    freeSpace(pPg, aOfst[j], aAfter[j]-aOfst[j]);
+  }
+  return nRet;
+}
+
+/*
+** pCArray contains pointers to and sizes of all cells in the page being
+** balanced.  The current page, pPg, has pPg->nCell cells starting with
+** pCArray->apCell[iOld].  After balancing, this page should hold nNew cells
+** starting at apCell[iNew].
+**
+** This routine makes the necessary adjustments to pPg so that it contains
+** the correct cells after being balanced.
+**
+** The pPg->nFree field is invalid when this function returns. It is the
+** responsibility of the caller to set it correctly.
+*/
+static int editPage(
+  MemPage *pPg,                   /* Edit this page */
+  int iOld,                       /* Index of first cell currently on page */
+  int iNew,                       /* Index of new first cell on page */
+  int nNew,                       /* Final number of cells on page */
+  CellArray *pCArray              /* Array of cells and sizes */
+){
+  u8 * const aData = pPg->aData;
+  const int hdr = pPg->hdrOffset;
+  u8 *pBegin = &pPg->aCellIdx[nNew * 2];
+  int nCell = pPg->nCell;       /* Cells stored on pPg */
+  u8 *pData;
+  u8 *pCellptr;
+  int i;
+  int iOldEnd = iOld + pPg->nCell + pPg->nOverflow;
+  int iNewEnd = iNew + nNew;
+
+#ifdef SQLITE_DEBUG
+  u8 *pTmp = sqlite3PagerTempSpace(pPg->pBt->pPager);
+  memcpy(pTmp, aData, pPg->pBt->usableSize);
+#endif
+
+  /* Remove cells from the start and end of the page */
+  assert( nCell>=0 );
+  if( iOld<iNew ){
+    int nShift = pageFreeArray(pPg, iOld, iNew-iOld, pCArray);
+    if( NEVER(nShift>nCell) ) return SQLITE_CORRUPT_BKPT;
+    memmove(pPg->aCellIdx, &pPg->aCellIdx[nShift*2], nCell*2);
+    nCell -= nShift;
+  }
+  if( iNewEnd < iOldEnd ){
+    int nTail = pageFreeArray(pPg, iNewEnd, iOldEnd - iNewEnd, pCArray);
+    assert( nCell>=nTail );
+    nCell -= nTail;
+  }
+
+  pData = &aData[get2byte(&aData[hdr+5])];
+  if( pData<pBegin ) goto editpage_fail;
+  if( NEVER(pData>pPg->aDataEnd) ) goto editpage_fail;
+
+  /* Add cells to the start of the page */
+  if( iNew<iOld ){
+    int nAdd = MIN(nNew,iOld-iNew);
+    assert( (iOld-iNew)<nNew || nCell==0 || CORRUPT_DB );
+    assert( nAdd>=0 );
+    pCellptr = pPg->aCellIdx;
+    memmove(&pCellptr[nAdd*2], pCellptr, nCell*2);
+    if( pageInsertArray(
+          pPg, pBegin, &pData, pCellptr,
+          iNew, nAdd, pCArray
+    ) ) goto editpage_fail;
+    nCell += nAdd;
+  }
+
+  /* Add any overflow cells */
+  for(i=0; i<pPg->nOverflow; i++){
+    int iCell = (iOld + pPg->aiOvfl[i]) - iNew;
+    if( iCell>=0 && iCell<nNew ){
+      pCellptr = &pPg->aCellIdx[iCell * 2];
+      if( nCell>iCell ){
+        memmove(&pCellptr[2], pCellptr, (nCell - iCell) * 2);
+      }
+      nCell++;
+      cachedCellSize(pCArray, iCell+iNew);
+      if( pageInsertArray(
+            pPg, pBegin, &pData, pCellptr,
+            iCell+iNew, 1, pCArray
+      ) ) goto editpage_fail;
+    }
+  }
+
+  /* Append cells to the end of the page */
+  assert( nCell>=0 );
+  pCellptr = &pPg->aCellIdx[nCell*2];
+  if( pageInsertArray(
+        pPg, pBegin, &pData, pCellptr,
+        iNew+nCell, nNew-nCell, pCArray
+  ) ) goto editpage_fail;
+
+  pPg->nCell = nNew;
+  pPg->nOverflow = 0;
+
+  put2byte(&aData[hdr+3], pPg->nCell);
+  put2byte(&aData[hdr+5], pData - aData);
+
+#ifdef SQLITE_DEBUG
+  for(i=0; i<nNew && !CORRUPT_DB; i++){
+    u8 *pCell = pCArray->apCell[i+iNew];
+    int iOff = get2byteAligned(&pPg->aCellIdx[i*2]);
+    if( SQLITE_WITHIN(pCell, aData, &aData[pPg->pBt->usableSize]) ){
+      pCell = &pTmp[pCell - aData];
+    }
+    assert( 0==memcmp(pCell, &aData[iOff],
+            pCArray->pRef->xCellSize(pCArray->pRef, pCArray->apCell[i+iNew])) );
+  }
+#endif
+
+  return SQLITE_OK;
+ editpage_fail:
+  /* Unable to edit this page. Rebuild it from scratch instead. */
+  if( nNew<1 ) return SQLITE_CORRUPT_BKPT;
+  populateCellCache(pCArray, iNew, nNew);
+  return rebuildPage(pCArray, iNew, nNew, pPg);
+}
+
+
+#ifndef SQLITE_OMIT_QUICKBALANCE
+/*
+** This version of balance() handles the common special case where
+** a new entry is being inserted on the extreme right-end of the
+** tree, in other words, when the new entry will become the largest
+** entry in the tree.
+**
+** Instead of trying to balance the 3 right-most leaf pages, just add
+** a new page to the right-hand side and put the one new entry in
+** that page.  This leaves the right side of the tree somewhat
+** unbalanced.  But odds are that we will be inserting new entries
+** at the end soon afterwards so the nearly empty page will quickly
+** fill up.  On average.
+**
+** pPage is the leaf page which is the right-most page in the tree.
+** pParent is its parent.  pPage must have a single overflow entry
+** which is also the right-most entry on the page.
+**
+** The pSpace buffer is used to store a temporary copy of the divider
+** cell that will be inserted into pParent. Such a cell consists of a 4
+** byte page number followed by a variable length integer. In other
+** words, at most 13 bytes. Hence the pSpace buffer must be at
+** least 13 bytes in size.
+*/
+static int balance_quick(MemPage *pParent, MemPage *pPage, u8 *pSpace){
+  BtShared *const pBt = pPage->pBt;    /* B-Tree Database */
+  MemPage *pNew;                       /* Newly allocated page */
+  int rc;                              /* Return Code */
+  Pgno pgnoNew;                        /* Page number of pNew */
+
+  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+  assert( pPage->nOverflow==1 );
+
+  if( pPage->nCell==0 ) return SQLITE_CORRUPT_BKPT;  /* dbfuzz001.test */
+  assert( pPage->nFree>=0 );
+  assert( pParent->nFree>=0 );
+
+  /* Allocate a new page. This page will become the right-sibling of
+  ** pPage. Make the parent page writable, so that the new divider cell
+  ** may be inserted. If both these operations are successful, proceed.
+  */
+  rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
+
+  if( rc==SQLITE_OK ){
+
+    u8 *pOut = &pSpace[4];
+    u8 *pCell = pPage->apOvfl[0];
+    u16 szCell = pPage->xCellSize(pPage, pCell);
+    u8 *pStop;
+    CellArray b;
+
+    assert( sqlite3PagerIswriteable(pNew->pDbPage) );
+    assert( CORRUPT_DB || pPage->aData[0]==(PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF) );
+    zeroPage(pNew, PTF_INTKEY|PTF_LEAFDATA|PTF_LEAF);
+    b.nCell = 1;
+    b.pRef = pPage;
+    b.apCell = &pCell;
+    b.szCell = &szCell;
+    b.apEnd[0] = pPage->aDataEnd;
+    b.ixNx[0] = 2;
+    b.ixNx[NB*2-1] = 0x7fffffff;
+    rc = rebuildPage(&b, 0, 1, pNew);
+    if( NEVER(rc) ){
+      releasePage(pNew);
+      return rc;
+    }
+    pNew->nFree = pBt->usableSize - pNew->cellOffset - 2 - szCell;
+
+    /* If this is an auto-vacuum database, update the pointer map
+    ** with entries for the new page, and any pointer from the
+    ** cell on the page to an overflow page. If either of these
+    ** operations fails, the return code is set, but the contents
+    ** of the parent page are still manipulated by the code below.
+    ** That is Ok, at this point the parent page is guaranteed to
+    ** be marked as dirty. Returning an error code will cause a
+    ** rollback, undoing any changes made to the parent page.
+    */
+    if( ISAUTOVACUUM(pBt) ){
+      ptrmapPut(pBt, pgnoNew, PTRMAP_BTREE, pParent->pgno, &rc);
+      if( szCell>pNew->minLocal ){
+        ptrmapPutOvflPtr(pNew, pNew, pCell, &rc);
+      }
+    }
+
+    /* Create a divider cell to insert into pParent. The divider cell
+    ** consists of a 4-byte page number (the page number of pPage) and
+    ** a variable length key value (which must be the same value as the
+    ** largest key on pPage).
+    **
+    ** To find the largest key value on pPage, first find the right-most
+    ** cell on pPage. The first two fields of this cell are the
+    ** record-length (a variable length integer at most 32-bits in size)
+    ** and the key value (a variable length integer, may have any value).
+    ** The first of the while(...) loops below skips over the record-length
+    ** field. The second while(...) loop copies the key value from the
+    ** cell on pPage into the pSpace buffer.
+    */
+    pCell = findCell(pPage, pPage->nCell-1);
+    pStop = &pCell[9];
+    while( (*(pCell++)&0x80) && pCell<pStop );
+    pStop = &pCell[9];
+    while( ((*(pOut++) = *(pCell++))&0x80) && pCell<pStop );
+
+    /* Insert the new divider cell into pParent. */
+    if( rc==SQLITE_OK ){
+      rc = insertCell(pParent, pParent->nCell, pSpace, (int)(pOut-pSpace),
+                      0, pPage->pgno);
+    }
+
+    /* Set the right-child pointer of pParent to point to the new page. */
+    put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew);
+
+    /* Release the reference to the new page. */
+    releasePage(pNew);
+  }
+
+  return rc;
+}
+#endif /* SQLITE_OMIT_QUICKBALANCE */
+
+#if 0
+/*
+** This function does not contribute anything to the operation of SQLite.
+** it is sometimes activated temporarily while debugging code responsible
+** for setting pointer-map entries.
+*/
+static int ptrmapCheckPages(MemPage **apPage, int nPage){
+  int i, j;
+  for(i=0; i<nPage; i++){
+    Pgno n;
+    u8 e;
+    MemPage *pPage = apPage[i];
+    BtShared *pBt = pPage->pBt;
+    assert( pPage->isInit );
+
+    for(j=0; j<pPage->nCell; j++){
+      CellInfo info;
+      u8 *z;
+
+      z = findCell(pPage, j);
+      pPage->xParseCell(pPage, z, &info);
+      if( info.nLocal<info.nPayload ){
+        Pgno ovfl = get4byte(&z[info.nSize-4]);
+        ptrmapGet(pBt, ovfl, &e, &n);
+        assert( n==pPage->pgno && e==PTRMAP_OVERFLOW1 );
+      }
+      if( !pPage->leaf ){
+        Pgno child = get4byte(z);
+        ptrmapGet(pBt, child, &e, &n);
+        assert( n==pPage->pgno && e==PTRMAP_BTREE );
+      }
+    }
+    if( !pPage->leaf ){
+      Pgno child = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+      ptrmapGet(pBt, child, &e, &n);
+      assert( n==pPage->pgno && e==PTRMAP_BTREE );
+    }
+  }
+  return 1;
+}
+#endif
+
+/*
+** This function is used to copy the contents of the b-tree node stored
+** on page pFrom to page pTo. If page pFrom was not a leaf page, then
+** the pointer-map entries for each child page are updated so that the
+** parent page stored in the pointer map is page pTo. If pFrom contained
+** any cells with overflow page pointers, then the corresponding pointer
+** map entries are also updated so that the parent page is page pTo.
+**
+** If pFrom is currently carrying any overflow cells (entries in the
+** MemPage.apOvfl[] array), they are not copied to pTo.
+**
+** Before returning, page pTo is reinitialized using btreeInitPage().
+**
+** The performance of this function is not critical. It is only used by
+** the balance_shallower() and balance_deeper() procedures, neither of
+** which are called often under normal circumstances.
+*/
+static void copyNodeContent(MemPage *pFrom, MemPage *pTo, int *pRC){
+  if( (*pRC)==SQLITE_OK ){
+    BtShared * const pBt = pFrom->pBt;
+    u8 * const aFrom = pFrom->aData;
+    u8 * const aTo = pTo->aData;
+    int const iFromHdr = pFrom->hdrOffset;
+    int const iToHdr = ((pTo->pgno==1) ? 100 : 0);
+    int rc;
+    int iData;
+
+
+    assert( pFrom->isInit );
+    assert( pFrom->nFree>=iToHdr );
+    assert( get2byte(&aFrom[iFromHdr+5]) <= (int)pBt->usableSize );
+
+    /* Copy the b-tree node content from page pFrom to page pTo. */
+    iData = get2byte(&aFrom[iFromHdr+5]);
+    memcpy(&aTo[iData], &aFrom[iData], pBt->usableSize-iData);
+    memcpy(&aTo[iToHdr], &aFrom[iFromHdr], pFrom->cellOffset + 2*pFrom->nCell);
+
+    /* Reinitialize page pTo so that the contents of the MemPage structure
+    ** match the new data. The initialization of pTo can actually fail under
+    ** fairly obscure circumstances, even though it is a copy of initialized
+    ** page pFrom.
+    */
+    pTo->isInit = 0;
+    rc = btreeInitPage(pTo);
+    if( rc==SQLITE_OK ) rc = btreeComputeFreeSpace(pTo);
+    if( rc!=SQLITE_OK ){
+      *pRC = rc;
+      return;
+    }
+
+    /* If this is an auto-vacuum database, update the pointer-map entries
+    ** for any b-tree or overflow pages that pTo now contains the pointers to.
+    */
+    if( ISAUTOVACUUM(pBt) ){
+      *pRC = setChildPtrmaps(pTo);
+    }
+  }
+}
+
+/*
+** This routine redistributes cells on the iParentIdx'th child of pParent
+** (hereafter "the page") and up to 2 siblings so that all pages have about the
+** same amount of free space. Usually a single sibling on either side of the
+** page are used in the balancing, though both siblings might come from one
+** side if the page is the first or last child of its parent. If the page
+** has fewer than 2 siblings (something which can only happen if the page
+** is a root page or a child of a root page) then all available siblings
+** participate in the balancing.
+**
+** The number of siblings of the page might be increased or decreased by
+** one or two in an effort to keep pages nearly full but not over full.
+**
+** Note that when this routine is called, some of the cells on the page
+** might not actually be stored in MemPage.aData[]. This can happen
+** if the page is overfull. This routine ensures that all cells allocated
+** to the page and its siblings fit into MemPage.aData[] before returning.
+**
+** In the course of balancing the page and its siblings, cells may be
+** inserted into or removed from the parent page (pParent). Doing so
+** may cause the parent page to become overfull or underfull. If this
+** happens, it is the responsibility of the caller to invoke the correct
+** balancing routine to fix this problem (see the balance() routine).
+**
+** If this routine fails for any reason, it might leave the database
+** in a corrupted state. So if this routine fails, the database should
+** be rolled back.
+**
+** The third argument to this function, aOvflSpace, is a pointer to a
+** buffer big enough to hold one page. If while inserting cells into the parent
+** page (pParent) the parent page becomes overfull, this buffer is
+** used to store the parent's overflow cells. Because this function inserts
+** a maximum of four divider cells into the parent page, and the maximum
+** size of a cell stored within an internal node is always less than 1/4
+** of the page-size, the aOvflSpace[] buffer is guaranteed to be large
+** enough for all overflow cells.
+**
+** If aOvflSpace is set to a null pointer, this function returns
+** SQLITE_NOMEM.
+*/
+static int balance_nonroot(
+  MemPage *pParent,               /* Parent page of siblings being balanced */
+  int iParentIdx,                 /* Index of "the page" in pParent */
+  u8 *aOvflSpace,                 /* page-size bytes of space for parent ovfl */
+  int isRoot,                     /* True if pParent is a root-page */
+  int bBulk                       /* True if this call is part of a bulk load */
+){
+  BtShared *pBt;               /* The whole database */
+  int nMaxCells = 0;           /* Allocated size of apCell, szCell, aFrom. */
+  int nNew = 0;                /* Number of pages in apNew[] */
+  int nOld;                    /* Number of pages in apOld[] */
+  int i, j, k;                 /* Loop counters */
+  int nxDiv;                   /* Next divider slot in pParent->aCell[] */
+  int rc = SQLITE_OK;          /* The return code */
+  u16 leafCorrection;          /* 4 if pPage is a leaf.  0 if not */
+  int leafData;                /* True if pPage is a leaf of a LEAFDATA tree */
+  int usableSpace;             /* Bytes in pPage beyond the header */
+  int pageFlags;               /* Value of pPage->aData[0] */
+  int iSpace1 = 0;             /* First unused byte of aSpace1[] */
+  int iOvflSpace = 0;          /* First unused byte of aOvflSpace[] */
+  int szScratch;               /* Size of scratch memory requested */
+  MemPage *apOld[NB];          /* pPage and up to two siblings */
+  MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
+  u8 *pRight;                  /* Location in parent of right-sibling pointer */
+  u8 *apDiv[NB-1];             /* Divider cells in pParent */
+  int cntNew[NB+2];            /* Index in b.paCell[] of cell after i-th page */
+  int cntOld[NB+2];            /* Old index in b.apCell[] */
+  int szNew[NB+2];             /* Combined size of cells placed on i-th page */
+  u8 *aSpace1;                 /* Space for copies of dividers cells */
+  Pgno pgno;                   /* Temp var to store a page number in */
+  u8 abDone[NB+2];             /* True after i'th new page is populated */
+  Pgno aPgno[NB+2];            /* Page numbers of new pages before shuffling */
+  CellArray b;                 /* Parsed information on cells being balanced */
+
+  memset(abDone, 0, sizeof(abDone));
+  assert( sizeof(b) - sizeof(b.ixNx) == offsetof(CellArray,ixNx) );
+  memset(&b, 0, sizeof(b)-sizeof(b.ixNx[0]));
+  b.ixNx[NB*2-1] = 0x7fffffff;
+  pBt = pParent->pBt;
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+
+  /* At this point pParent may have at most one overflow cell. And if
+  ** this overflow cell is present, it must be the cell with
+  ** index iParentIdx. This scenario comes about when this function
+  ** is called (indirectly) from sqlite3BtreeDelete().
+  */
+  assert( pParent->nOverflow==0 || pParent->nOverflow==1 );
+  assert( pParent->nOverflow==0 || pParent->aiOvfl[0]==iParentIdx );
+
+  if( !aOvflSpace ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( pParent->nFree>=0 );
+
+  /* Find the sibling pages to balance. Also locate the cells in pParent
+  ** that divide the siblings. An attempt is made to find NN siblings on
+  ** either side of pPage. More siblings are taken from one side, however,
+  ** if there are fewer than NN siblings on the other side. If pParent
+  ** has NB or fewer children then all children of pParent are taken.
+  **
+  ** This loop also drops the divider cells from the parent page. This
+  ** way, the remainder of the function does not have to deal with any
+  ** overflow cells in the parent page, since if any existed they will
+  ** have already been removed.
+  */
+  i = pParent->nOverflow + pParent->nCell;
+  if( i<2 ){
+    nxDiv = 0;
+  }else{
+    assert( bBulk==0 || bBulk==1 );
+    if( iParentIdx==0 ){
+      nxDiv = 0;
+    }else if( iParentIdx==i ){
+      nxDiv = i-2+bBulk;
+    }else{
+      nxDiv = iParentIdx-1;
+    }
+    i = 2-bBulk;
+  }
+  nOld = i+1;
+  if( (i+nxDiv-pParent->nOverflow)==pParent->nCell ){
+    pRight = &pParent->aData[pParent->hdrOffset+8];
+  }else{
+    pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
+  }
+  pgno = get4byte(pRight);
+  while( 1 ){
+    if( rc==SQLITE_OK ){
+      rc = getAndInitPage(pBt, pgno, &apOld[i], 0);
+    }
+    if( rc ){
+      memset(apOld, 0, (i+1)*sizeof(MemPage*));
+      goto balance_cleanup;
+    }
+    if( apOld[i]->nFree<0 ){
+      rc = btreeComputeFreeSpace(apOld[i]);
+      if( rc ){
+        memset(apOld, 0, (i)*sizeof(MemPage*));
+        goto balance_cleanup;
+      }
+    }
+    nMaxCells += apOld[i]->nCell + ArraySize(pParent->apOvfl);
+    if( (i--)==0 ) break;
+
+    if( pParent->nOverflow && i+nxDiv==pParent->aiOvfl[0] ){
+      apDiv[i] = pParent->apOvfl[0];
+      pgno = get4byte(apDiv[i]);
+      szNew[i] = pParent->xCellSize(pParent, apDiv[i]);
+      pParent->nOverflow = 0;
+    }else{
+      apDiv[i] = findCell(pParent, i+nxDiv-pParent->nOverflow);
+      pgno = get4byte(apDiv[i]);
+      szNew[i] = pParent->xCellSize(pParent, apDiv[i]);
+
+      /* Drop the cell from the parent page. apDiv[i] still points to
+      ** the cell within the parent, even though it has been dropped.
+      ** This is safe because dropping a cell only overwrites the first
+      ** four bytes of it, and this function does not need the first
+      ** four bytes of the divider cell. So the pointer is safe to use
+      ** later on.
+      **
+      ** But not if we are in secure-delete mode. In secure-delete mode,
+      ** the dropCell() routine will overwrite the entire cell with zeroes.
+      ** In this case, temporarily copy the cell into the aOvflSpace[]
+      ** buffer. It will be copied out again as soon as the aSpace[] buffer
+      ** is allocated.  */
+      if( pBt->btsFlags & BTS_FAST_SECURE ){
+        int iOff;
+
+        /* If the following if() condition is not true, the db is corrupted.
+        ** The call to dropCell() below will detect this.  */
+        iOff = SQLITE_PTR_TO_INT(apDiv[i]) - SQLITE_PTR_TO_INT(pParent->aData);
+        if( (iOff+szNew[i])<=(int)pBt->usableSize ){
+          memcpy(&aOvflSpace[iOff], apDiv[i], szNew[i]);
+          apDiv[i] = &aOvflSpace[apDiv[i]-pParent->aData];
+        }
+      }
+      dropCell(pParent, i+nxDiv-pParent->nOverflow, szNew[i], &rc);
+    }
+  }
+
+  /* Make nMaxCells a multiple of 4 in order to preserve 8-byte
+  ** alignment */
+  nMaxCells = (nMaxCells + 3)&~3;
+
+  /*
+  ** Allocate space for memory structures
+  */
+  szScratch =
+       nMaxCells*sizeof(u8*)                       /* b.apCell */
+     + nMaxCells*sizeof(u16)                       /* b.szCell */
+     + pBt->pageSize;                              /* aSpace1 */
+
+  assert( szScratch<=7*(int)pBt->pageSize );
+  b.apCell = sqlite3StackAllocRaw(0, szScratch );
+  if( b.apCell==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto balance_cleanup;
+  }
+  b.szCell = (u16*)&b.apCell[nMaxCells];
+  aSpace1 = (u8*)&b.szCell[nMaxCells];
+  assert( EIGHT_BYTE_ALIGNMENT(aSpace1) );
+
+  /*
+  ** Load pointers to all cells on sibling pages and the divider cells
+  ** into the local b.apCell[] array.  Make copies of the divider cells
+  ** into space obtained from aSpace1[]. The divider cells have already
+  ** been removed from pParent.
+  **
+  ** If the siblings are on leaf pages, then the child pointers of the
+  ** divider cells are stripped from the cells before they are copied
+  ** into aSpace1[].  In this way, all cells in b.apCell[] are without
+  ** child pointers.  If siblings are not leaves, then all cell in
+  ** b.apCell[] include child pointers.  Either way, all cells in b.apCell[]
+  ** are alike.
+  **
+  ** leafCorrection:  4 if pPage is a leaf.  0 if pPage is not a leaf.
+  **       leafData:  1 if pPage holds key+data and pParent holds only keys.
+  */
+  b.pRef = apOld[0];
+  leafCorrection = b.pRef->leaf*4;
+  leafData = b.pRef->intKeyLeaf;
+  for(i=0; i<nOld; i++){
+    MemPage *pOld = apOld[i];
+    int limit = pOld->nCell;
+    u8 *aData = pOld->aData;
+    u16 maskPage = pOld->maskPage;
+    u8 *piCell = aData + pOld->cellOffset;
+    u8 *piEnd;
+    VVA_ONLY( int nCellAtStart = b.nCell; )
+
+    /* Verify that all sibling pages are of the same "type" (table-leaf,
+    ** table-interior, index-leaf, or index-interior).
+    */
+    if( pOld->aData[0]!=apOld[0]->aData[0] ){
+      rc = SQLITE_CORRUPT_PAGE(pOld);
+      goto balance_cleanup;
+    }
+
+    /* Load b.apCell[] with pointers to all cells in pOld.  If pOld
+    ** contains overflow cells, include them in the b.apCell[] array
+    ** in the correct spot.
+    **
+    ** Note that when there are multiple overflow cells, it is always the
+    ** case that they are sequential and adjacent.  This invariant arises
+    ** because multiple overflows can only occurs when inserting divider
+    ** cells into a parent on a prior balance, and divider cells are always
+    ** adjacent and are inserted in order.  There is an assert() tagged
+    ** with "NOTE 1" in the overflow cell insertion loop to prove this
+    ** invariant.
+    **
+    ** This must be done in advance.  Once the balance starts, the cell
+    ** offset section of the btree page will be overwritten and we will no
+    ** long be able to find the cells if a pointer to each cell is not saved
+    ** first.
+    */
+    memset(&b.szCell[b.nCell], 0, sizeof(b.szCell[0])*(limit+pOld->nOverflow));
+    if( pOld->nOverflow>0 ){
+      if( NEVER(limit<pOld->aiOvfl[0]) ){
+        rc = SQLITE_CORRUPT_PAGE(pOld);
+        goto balance_cleanup;
+      }
+      limit = pOld->aiOvfl[0];
+      for(j=0; j<limit; j++){
+        b.apCell[b.nCell] = aData + (maskPage & get2byteAligned(piCell));
+        piCell += 2;
+        b.nCell++;
+      }
+      for(k=0; k<pOld->nOverflow; k++){
+        assert( k==0 || pOld->aiOvfl[k-1]+1==pOld->aiOvfl[k] );/* NOTE 1 */
+        b.apCell[b.nCell] = pOld->apOvfl[k];
+        b.nCell++;
+      }
+    }
+    piEnd = aData + pOld->cellOffset + 2*pOld->nCell;
+    while( piCell<piEnd ){
+      assert( b.nCell<nMaxCells );
+      b.apCell[b.nCell] = aData + (maskPage & get2byteAligned(piCell));
+      piCell += 2;
+      b.nCell++;
+    }
+    assert( (b.nCell-nCellAtStart)==(pOld->nCell+pOld->nOverflow) );
+
+    cntOld[i] = b.nCell;
+    if( i<nOld-1 && !leafData){
+      u16 sz = (u16)szNew[i];
+      u8 *pTemp;
+      assert( b.nCell<nMaxCells );
+      b.szCell[b.nCell] = sz;
+      pTemp = &aSpace1[iSpace1];
+      iSpace1 += sz;
+      assert( sz<=pBt->maxLocal+23 );
+      assert( iSpace1 <= (int)pBt->pageSize );
+      memcpy(pTemp, apDiv[i], sz);
+      b.apCell[b.nCell] = pTemp+leafCorrection;
+      assert( leafCorrection==0 || leafCorrection==4 );
+      b.szCell[b.nCell] = b.szCell[b.nCell] - leafCorrection;
+      if( !pOld->leaf ){
+        assert( leafCorrection==0 );
+        assert( pOld->hdrOffset==0 || CORRUPT_DB );
+        /* The right pointer of the child page pOld becomes the left
+        ** pointer of the divider cell */
+        memcpy(b.apCell[b.nCell], &pOld->aData[8], 4);
+      }else{
+        assert( leafCorrection==4 );
+        while( b.szCell[b.nCell]<4 ){
+          /* Do not allow any cells smaller than 4 bytes. If a smaller cell
+          ** does exist, pad it with 0x00 bytes. */
+          assert( b.szCell[b.nCell]==3 || CORRUPT_DB );
+          assert( b.apCell[b.nCell]==&aSpace1[iSpace1-3] || CORRUPT_DB );
+          aSpace1[iSpace1++] = 0x00;
+          b.szCell[b.nCell]++;
+        }
+      }
+      b.nCell++;
+    }
+  }
+
+  /*
+  ** Figure out the number of pages needed to hold all b.nCell cells.
+  ** Store this number in "k".  Also compute szNew[] which is the total
+  ** size of all cells on the i-th page and cntNew[] which is the index
+  ** in b.apCell[] of the cell that divides page i from page i+1.
+  ** cntNew[k] should equal b.nCell.
+  **
+  ** Values computed by this block:
+  **
+  **           k: The total number of sibling pages
+  **    szNew[i]: Spaced used on the i-th sibling page.
+  **   cntNew[i]: Index in b.apCell[] and b.szCell[] for the first cell to
+  **              the right of the i-th sibling page.
+  ** usableSpace: Number of bytes of space available on each sibling.
+  **
+  */
+  usableSpace = pBt->usableSize - 12 + leafCorrection;
+  for(i=k=0; i<nOld; i++, k++){
+    MemPage *p = apOld[i];
+    b.apEnd[k] = p->aDataEnd;
+    b.ixNx[k] = cntOld[i];
+    if( k && b.ixNx[k]==b.ixNx[k-1] ){
+      k--;  /* Omit b.ixNx[] entry for child pages with no cells */
+    }
+    if( !leafData ){
+      k++;
+      b.apEnd[k] = pParent->aDataEnd;
+      b.ixNx[k] = cntOld[i]+1;
+    }
+    assert( p->nFree>=0 );
+    szNew[i] = usableSpace - p->nFree;
+    for(j=0; j<p->nOverflow; j++){
+      szNew[i] += 2 + p->xCellSize(p, p->apOvfl[j]);
+    }
+    cntNew[i] = cntOld[i];
+  }
+  k = nOld;
+  for(i=0; i<k; i++){
+    int sz;
+    while( szNew[i]>usableSpace ){
+      if( i+1>=k ){
+        k = i+2;
+        if( k>NB+2 ){ rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; }
+        szNew[k-1] = 0;
+        cntNew[k-1] = b.nCell;
+      }
+      sz = 2 + cachedCellSize(&b, cntNew[i]-1);
+      szNew[i] -= sz;
+      if( !leafData ){
+        if( cntNew[i]<b.nCell ){
+          sz = 2 + cachedCellSize(&b, cntNew[i]);
+        }else{
+          sz = 0;
+        }
+      }
+      szNew[i+1] += sz;
+      cntNew[i]--;
+    }
+    while( cntNew[i]<b.nCell ){
+      sz = 2 + cachedCellSize(&b, cntNew[i]);
+      if( szNew[i]+sz>usableSpace ) break;
+      szNew[i] += sz;
+      cntNew[i]++;
+      if( !leafData ){
+        if( cntNew[i]<b.nCell ){
+          sz = 2 + cachedCellSize(&b, cntNew[i]);
+        }else{
+          sz = 0;
+        }
+      }
+      szNew[i+1] -= sz;
+    }
+    if( cntNew[i]>=b.nCell ){
+      k = i+1;
+    }else if( cntNew[i] <= (i>0 ? cntNew[i-1] : 0) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto balance_cleanup;
+    }
+  }
+
+  /*
+  ** The packing computed by the previous block is biased toward the siblings
+  ** on the left side (siblings with smaller keys). The left siblings are
+  ** always nearly full, while the right-most sibling might be nearly empty.
+  ** The next block of code attempts to adjust the packing of siblings to
+  ** get a better balance.
+  **
+  ** This adjustment is more than an optimization.  The packing above might
+  ** be so out of balance as to be illegal.  For example, the right-most
+  ** sibling might be completely empty.  This adjustment is not optional.
+  */
+  for(i=k-1; i>0; i--){
+    int szRight = szNew[i];  /* Size of sibling on the right */
+    int szLeft = szNew[i-1]; /* Size of sibling on the left */
+    int r;              /* Index of right-most cell in left sibling */
+    int d;              /* Index of first cell to the left of right sibling */
+
+    r = cntNew[i-1] - 1;
+    d = r + 1 - leafData;
+    (void)cachedCellSize(&b, d);
+    do{
+      int szR, szD;
+      assert( d<nMaxCells );
+      assert( r<nMaxCells );
+      szR = cachedCellSize(&b, r);
+      szD = b.szCell[d];
+      if( szRight!=0
+       && (bBulk || szRight+szD+2 > szLeft-(szR+(i==k-1?0:2)))){
+        break;
+      }
+      szRight += szD + 2;
+      szLeft -= szR + 2;
+      cntNew[i-1] = r;
+      r--;
+      d--;
+    }while( r>=0 );
+    szNew[i] = szRight;
+    szNew[i-1] = szLeft;
+    if( cntNew[i-1] <= (i>1 ? cntNew[i-2] : 0) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto balance_cleanup;
+    }
+  }
+
+  /* Sanity check:  For a non-corrupt database file one of the following
+  ** must be true:
+  **    (1) We found one or more cells (cntNew[0])>0), or
+  **    (2) pPage is a virtual root page.  A virtual root page is when
+  **        the real root page is page 1 and we are the only child of
+  **        that page.
+  */
+  assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) || CORRUPT_DB);
+  TRACE(("BALANCE: old: %u(nc=%u) %u(nc=%u) %u(nc=%u)\n",
+    apOld[0]->pgno, apOld[0]->nCell,
+    nOld>=2 ? apOld[1]->pgno : 0, nOld>=2 ? apOld[1]->nCell : 0,
+    nOld>=3 ? apOld[2]->pgno : 0, nOld>=3 ? apOld[2]->nCell : 0
+  ));
+
+  /*
+  ** Allocate k new pages.  Reuse old pages where possible.
+  */
+  pageFlags = apOld[0]->aData[0];
+  for(i=0; i<k; i++){
+    MemPage *pNew;
+    if( i<nOld ){
+      pNew = apNew[i] = apOld[i];
+      apOld[i] = 0;
+      rc = sqlite3PagerWrite(pNew->pDbPage);
+      nNew++;
+      if( sqlite3PagerPageRefcount(pNew->pDbPage)!=1+(i==(iParentIdx-nxDiv))
+       && rc==SQLITE_OK
+      ){
+        rc = SQLITE_CORRUPT_BKPT;
+      }
+      if( rc ) goto balance_cleanup;
+    }else{
+      assert( i>0 );
+      rc = allocateBtreePage(pBt, &pNew, &pgno, (bBulk ? 1 : pgno), 0);
+      if( rc ) goto balance_cleanup;
+      zeroPage(pNew, pageFlags);
+      apNew[i] = pNew;
+      nNew++;
+      cntOld[i] = b.nCell;
+
+      /* Set the pointer-map entry for the new sibling page. */
+      if( ISAUTOVACUUM(pBt) ){
+        ptrmapPut(pBt, pNew->pgno, PTRMAP_BTREE, pParent->pgno, &rc);
+        if( rc!=SQLITE_OK ){
+          goto balance_cleanup;
+        }
+      }
+    }
+  }
+
+  /*
+  ** Reassign page numbers so that the new pages are in ascending order.
+  ** This helps to keep entries in the disk file in order so that a scan
+  ** of the table is closer to a linear scan through the file. That in turn
+  ** helps the operating system to deliver pages from the disk more rapidly.
+  **
+  ** An O(N*N) sort algorithm is used, but since N is never more than NB+2
+  ** (5), that is not a performance concern.
+  **
+  ** When NB==3, this one optimization makes the database about 25% faster
+  ** for large insertions and deletions.
+  */
+  for(i=0; i<nNew; i++){
+    aPgno[i] = apNew[i]->pgno;
+    assert( apNew[i]->pDbPage->flags & PGHDR_WRITEABLE );
+    assert( apNew[i]->pDbPage->flags & PGHDR_DIRTY );
+  }
+  for(i=0; i<nNew-1; i++){
+    int iB = i;
+    for(j=i+1; j<nNew; j++){
+      if( apNew[j]->pgno < apNew[iB]->pgno ) iB = j;
+    }
+
+    /* If apNew[i] has a page number that is bigger than any of the
+    ** subsequence apNew[i] entries, then swap apNew[i] with the subsequent
+    ** entry that has the smallest page number (which we know to be
+    ** entry apNew[iB]).
+    */
+    if( iB!=i ){
+      Pgno pgnoA = apNew[i]->pgno;
+      Pgno pgnoB = apNew[iB]->pgno;
+      Pgno pgnoTemp = (PENDING_BYTE/pBt->pageSize)+1;
+      u16 fgA = apNew[i]->pDbPage->flags;
+      u16 fgB = apNew[iB]->pDbPage->flags;
+      sqlite3PagerRekey(apNew[i]->pDbPage, pgnoTemp, fgB);
+      sqlite3PagerRekey(apNew[iB]->pDbPage, pgnoA, fgA);
+      sqlite3PagerRekey(apNew[i]->pDbPage, pgnoB, fgB);
+      apNew[i]->pgno = pgnoB;
+      apNew[iB]->pgno = pgnoA;
+    }
+  }
+
+  TRACE(("BALANCE: new: %u(%u nc=%u) %u(%u nc=%u) %u(%u nc=%u) "
+         "%u(%u nc=%u) %u(%u nc=%u)\n",
+    apNew[0]->pgno, szNew[0], cntNew[0],
+    nNew>=2 ? apNew[1]->pgno : 0, nNew>=2 ? szNew[1] : 0,
+    nNew>=2 ? cntNew[1] - cntNew[0] - !leafData : 0,
+    nNew>=3 ? apNew[2]->pgno : 0, nNew>=3 ? szNew[2] : 0,
+    nNew>=3 ? cntNew[2] - cntNew[1] - !leafData : 0,
+    nNew>=4 ? apNew[3]->pgno : 0, nNew>=4 ? szNew[3] : 0,
+    nNew>=4 ? cntNew[3] - cntNew[2] - !leafData : 0,
+    nNew>=5 ? apNew[4]->pgno : 0, nNew>=5 ? szNew[4] : 0,
+    nNew>=5 ? cntNew[4] - cntNew[3] - !leafData : 0
+  ));
+
+  assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+  assert( nNew>=1 && nNew<=ArraySize(apNew) );
+  assert( apNew[nNew-1]!=0 );
+  put4byte(pRight, apNew[nNew-1]->pgno);
+
+  /* If the sibling pages are not leaves, ensure that the right-child pointer
+  ** of the right-most new sibling page is set to the value that was
+  ** originally in the same field of the right-most old sibling page. */
+  if( (pageFlags & PTF_LEAF)==0 && nOld!=nNew ){
+    MemPage *pOld = (nNew>nOld ? apNew : apOld)[nOld-1];
+    memcpy(&apNew[nNew-1]->aData[8], &pOld->aData[8], 4);
+  }
+
+  /* Make any required updates to pointer map entries associated with
+  ** cells stored on sibling pages following the balance operation. Pointer
+  ** map entries associated with divider cells are set by the insertCell()
+  ** routine. The associated pointer map entries are:
+  **
+  **   a) if the cell contains a reference to an overflow chain, the
+  **      entry associated with the first page in the overflow chain, and
+  **
+  **   b) if the sibling pages are not leaves, the child page associated
+  **      with the cell.
+  **
+  ** If the sibling pages are not leaves, then the pointer map entry
+  ** associated with the right-child of each sibling may also need to be
+  ** updated. This happens below, after the sibling pages have been
+  ** populated, not here.
+  */
+  if( ISAUTOVACUUM(pBt) ){
+    MemPage *pOld;
+    MemPage *pNew = pOld = apNew[0];
+    int cntOldNext = pNew->nCell + pNew->nOverflow;
+    int iNew = 0;
+    int iOld = 0;
+
+    for(i=0; i<b.nCell; i++){
+      u8 *pCell = b.apCell[i];
+      while( i==cntOldNext ){
+        iOld++;
+        assert( iOld<nNew || iOld<nOld );
+        assert( iOld>=0 && iOld<NB );
+        pOld = iOld<nNew ? apNew[iOld] : apOld[iOld];
+        cntOldNext += pOld->nCell + pOld->nOverflow + !leafData;
+      }
+      if( i==cntNew[iNew] ){
+        pNew = apNew[++iNew];
+        if( !leafData ) continue;
+      }
+
+      /* Cell pCell is destined for new sibling page pNew. Originally, it
+      ** was either part of sibling page iOld (possibly an overflow cell),
+      ** or else the divider cell to the left of sibling page iOld. So,
+      ** if sibling page iOld had the same page number as pNew, and if
+      ** pCell really was a part of sibling page iOld (not a divider or
+      ** overflow cell), we can skip updating the pointer map entries.  */
+      if( iOld>=nNew
+       || pNew->pgno!=aPgno[iOld]
+       || !SQLITE_WITHIN(pCell,pOld->aData,pOld->aDataEnd)
+      ){
+        if( !leafCorrection ){
+          ptrmapPut(pBt, get4byte(pCell), PTRMAP_BTREE, pNew->pgno, &rc);
+        }
+        if( cachedCellSize(&b,i)>pNew->minLocal ){
+          ptrmapPutOvflPtr(pNew, pOld, pCell, &rc);
+        }
+        if( rc ) goto balance_cleanup;
+      }
+    }
+  }
+
+  /* Insert new divider cells into pParent. */
+  for(i=0; i<nNew-1; i++){
+    u8 *pCell;
+    u8 *pTemp;
+    int sz;
+    u8 *pSrcEnd;
+    MemPage *pNew = apNew[i];
+    j = cntNew[i];
+
+    assert( j<nMaxCells );
+    assert( b.apCell[j]!=0 );
+    pCell = b.apCell[j];
+    sz = b.szCell[j] + leafCorrection;
+    pTemp = &aOvflSpace[iOvflSpace];
+    if( !pNew->leaf ){
+      memcpy(&pNew->aData[8], pCell, 4);
+    }else if( leafData ){
+      /* If the tree is a leaf-data tree, and the siblings are leaves,
+      ** then there is no divider cell in b.apCell[]. Instead, the divider
+      ** cell consists of the integer key for the right-most cell of
+      ** the sibling-page assembled above only.
+      */
+      CellInfo info;
+      j--;
+      pNew->xParseCell(pNew, b.apCell[j], &info);
+      pCell = pTemp;
+      sz = 4 + putVarint(&pCell[4], info.nKey);
+      pTemp = 0;
+    }else{
+      pCell -= 4;
+      /* Obscure case for non-leaf-data trees: If the cell at pCell was
+      ** previously stored on a leaf node, and its reported size was 4
+      ** bytes, then it may actually be smaller than this
+      ** (see btreeParseCellPtr(), 4 bytes is the minimum size of
+      ** any cell). But it is important to pass the correct size to
+      ** insertCell(), so reparse the cell now.
+      **
+      ** This can only happen for b-trees used to evaluate "IN (SELECT ...)"
+      ** and WITHOUT ROWID tables with exactly one column which is the
+      ** primary key.
+      */
+      if( b.szCell[j]==4 ){
+        assert(leafCorrection==4);
+        sz = pParent->xCellSize(pParent, pCell);
+      }
+    }
+    iOvflSpace += sz;
+    assert( sz<=pBt->maxLocal+23 );
+    assert( iOvflSpace <= (int)pBt->pageSize );
+    assert( b.ixNx[NB*2-1]>j );
+    for(k=0; b.ixNx[k]<=j; k++){}
+    pSrcEnd = b.apEnd[k];
+    if( SQLITE_OVERFLOW(pSrcEnd, pCell, pCell+sz) ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto balance_cleanup;
+    }
+    rc = insertCell(pParent, nxDiv+i, pCell, sz, pTemp, pNew->pgno);
+    if( rc!=SQLITE_OK ) goto balance_cleanup;
+    assert( sqlite3PagerIswriteable(pParent->pDbPage) );
+  }
+
+  /* Now update the actual sibling pages. The order in which they are updated
+  ** is important, as this code needs to avoid disrupting any page from which
+  ** cells may still to be read. In practice, this means:
+  **
+  **  (1) If cells are moving left (from apNew[iPg] to apNew[iPg-1])
+  **      then it is not safe to update page apNew[iPg] until after
+  **      the left-hand sibling apNew[iPg-1] has been updated.
+  **
+  **  (2) If cells are moving right (from apNew[iPg] to apNew[iPg+1])
+  **      then it is not safe to update page apNew[iPg] until after
+  **      the right-hand sibling apNew[iPg+1] has been updated.
+  **
+  ** If neither of the above apply, the page is safe to update.
+  **
+  ** The iPg value in the following loop starts at nNew-1 goes down
+  ** to 0, then back up to nNew-1 again, thus making two passes over
+  ** the pages.  On the initial downward pass, only condition (1) above
+  ** needs to be tested because (2) will always be true from the previous
+  ** step.  On the upward pass, both conditions are always true, so the
+  ** upwards pass simply processes pages that were missed on the downward
+  ** pass.
+  */
+  for(i=1-nNew; i<nNew; i++){
+    int iPg = i<0 ? -i : i;
+    assert( iPg>=0 && iPg<nNew );
+    assert( iPg>=1 || i>=0 );
+    assert( iPg<ArraySize(cntOld) );
+    if( abDone[iPg] ) continue;         /* Skip pages already processed */
+    if( i>=0                            /* On the upwards pass, or... */
+     || cntOld[iPg-1]>=cntNew[iPg-1]    /* Condition (1) is true */
+    ){
+      int iNew;
+      int iOld;
+      int nNewCell;
+
+      /* Verify condition (1):  If cells are moving left, update iPg
+      ** only after iPg-1 has already been updated. */
+      assert( iPg==0 || cntOld[iPg-1]>=cntNew[iPg-1] || abDone[iPg-1] );
+
+      /* Verify condition (2):  If cells are moving right, update iPg
+      ** only after iPg+1 has already been updated. */
+      assert( cntNew[iPg]>=cntOld[iPg] || abDone[iPg+1] );
+
+      if( iPg==0 ){
+        iNew = iOld = 0;
+        nNewCell = cntNew[0];
+      }else{
+        iOld = iPg<nOld ? (cntOld[iPg-1] + !leafData) : b.nCell;
+        iNew = cntNew[iPg-1] + !leafData;
+        nNewCell = cntNew[iPg] - iNew;
+      }
+
+      rc = editPage(apNew[iPg], iOld, iNew, nNewCell, &b);
+      if( rc ) goto balance_cleanup;
+      abDone[iPg]++;
+      apNew[iPg]->nFree = usableSpace-szNew[iPg];
+      assert( apNew[iPg]->nOverflow==0 );
+      assert( apNew[iPg]->nCell==nNewCell );
+    }
+  }
+
+  /* All pages have been processed exactly once */
+  assert( memcmp(abDone, "\01\01\01\01\01", nNew)==0 );
+
+  assert( nOld>0 );
+  assert( nNew>0 );
+
+  if( isRoot && pParent->nCell==0 && pParent->hdrOffset<=apNew[0]->nFree ){
+    /* The root page of the b-tree now contains no cells. The only sibling
+    ** page is the right-child of the parent. Copy the contents of the
+    ** child page into the parent, decreasing the overall height of the
+    ** b-tree structure by one. This is described as the "balance-shallower"
+    ** sub-algorithm in some documentation.
+    **
+    ** If this is an auto-vacuum database, the call to copyNodeContent()
+    ** sets all pointer-map entries corresponding to database image pages
+    ** for which the pointer is stored within the content being copied.
+    **
+    ** It is critical that the child page be defragmented before being
+    ** copied into the parent, because if the parent is page 1 then it will
+    ** by smaller than the child due to the database header, and so all the
+    ** free space needs to be up front.
+    */
+    assert( nNew==1 || CORRUPT_DB );
+    rc = defragmentPage(apNew[0], -1);
+    testcase( rc!=SQLITE_OK );
+    assert( apNew[0]->nFree ==
+        (get2byteNotZero(&apNew[0]->aData[5]) - apNew[0]->cellOffset
+          - apNew[0]->nCell*2)
+      || rc!=SQLITE_OK
+    );
+    copyNodeContent(apNew[0], pParent, &rc);
+    freePage(apNew[0], &rc);
+  }else if( ISAUTOVACUUM(pBt) && !leafCorrection ){
+    /* Fix the pointer map entries associated with the right-child of each
+    ** sibling page. All other pointer map entries have already been taken
+    ** care of.  */
+    for(i=0; i<nNew; i++){
+      u32 key = get4byte(&apNew[i]->aData[8]);
+      ptrmapPut(pBt, key, PTRMAP_BTREE, apNew[i]->pgno, &rc);
+    }
+  }
+
+  assert( pParent->isInit );
+  TRACE(("BALANCE: finished: old=%u new=%u cells=%u\n",
+          nOld, nNew, b.nCell));
+
+  /* Free any old pages that were not reused as new pages.
+  */
+  for(i=nNew; i<nOld; i++){
+    freePage(apOld[i], &rc);
+  }
+
+#if 0
+  if( ISAUTOVACUUM(pBt) && rc==SQLITE_OK && apNew[0]->isInit ){
+    /* The ptrmapCheckPages() contains assert() statements that verify that
+    ** all pointer map pages are set correctly. This is helpful while
+    ** debugging. This is usually disabled because a corrupt database may
+    ** cause an assert() statement to fail.  */
+    ptrmapCheckPages(apNew, nNew);
+    ptrmapCheckPages(&pParent, 1);
+  }
+#endif
+
+  /*
+  ** Cleanup before returning.
+  */
+balance_cleanup:
+  sqlite3StackFree(0, b.apCell);
+  for(i=0; i<nOld; i++){
+    releasePage(apOld[i]);
+  }
+  for(i=0; i<nNew; i++){
+    releasePage(apNew[i]);
+  }
+
+  return rc;
+}
+
+
+/*
+** This function is called when the root page of a b-tree structure is
+** overfull (has one or more overflow pages).
+**
+** A new child page is allocated and the contents of the current root
+** page, including overflow cells, are copied into the child. The root
+** page is then overwritten to make it an empty page with the right-child
+** pointer pointing to the new page.
+**
+** Before returning, all pointer-map entries corresponding to pages
+** that the new child-page now contains pointers to are updated. The
+** entry corresponding to the new right-child pointer of the root
+** page is also updated.
+**
+** If successful, *ppChild is set to contain a reference to the child
+** page and SQLITE_OK is returned. In this case the caller is required
+** to call releasePage() on *ppChild exactly once. If an error occurs,
+** an error code is returned and *ppChild is set to 0.
+*/
+static int balance_deeper(MemPage *pRoot, MemPage **ppChild){
+  int rc;                        /* Return value from subprocedures */
+  MemPage *pChild = 0;           /* Pointer to a new child page */
+  Pgno pgnoChild = 0;            /* Page number of the new child page */
+  BtShared *pBt = pRoot->pBt;    /* The BTree */
+
+  assert( pRoot->nOverflow>0 );
+  assert( sqlite3_mutex_held(pBt->mutex) );
+
+  /* Make pRoot, the root page of the b-tree, writable. Allocate a new
+  ** page that will become the new right-child of pPage. Copy the contents
+  ** of the node stored on pRoot into the new child page.
+  */
+  rc = sqlite3PagerWrite(pRoot->pDbPage);
+  if( rc==SQLITE_OK ){
+    rc = allocateBtreePage(pBt,&pChild,&pgnoChild,pRoot->pgno,0);
+    copyNodeContent(pRoot, pChild, &rc);
+    if( ISAUTOVACUUM(pBt) ){
+      ptrmapPut(pBt, pgnoChild, PTRMAP_BTREE, pRoot->pgno, &rc);
+    }
+  }
+  if( rc ){
+    *ppChild = 0;
+    releasePage(pChild);
+    return rc;
+  }
+  assert( sqlite3PagerIswriteable(pChild->pDbPage) );
+  assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
+  assert( pChild->nCell==pRoot->nCell || CORRUPT_DB );
+
+  TRACE(("BALANCE: copy root %u into %u\n", pRoot->pgno, pChild->pgno));
+
+  /* Copy the overflow cells from pRoot to pChild */
+  memcpy(pChild->aiOvfl, pRoot->aiOvfl,
+         pRoot->nOverflow*sizeof(pRoot->aiOvfl[0]));
+  memcpy(pChild->apOvfl, pRoot->apOvfl,
+         pRoot->nOverflow*sizeof(pRoot->apOvfl[0]));
+  pChild->nOverflow = pRoot->nOverflow;
+
+  /* Zero the contents of pRoot. Then install pChild as the right-child. */
+  zeroPage(pRoot, pChild->aData[0] & ~PTF_LEAF);
+  put4byte(&pRoot->aData[pRoot->hdrOffset+8], pgnoChild);
+
+  *ppChild = pChild;
+  return SQLITE_OK;
+}
+
+/*
+** Return SQLITE_CORRUPT if any cursor other than pCur is currently valid
+** on the same B-tree as pCur.
+**
+** This can occur if a database is corrupt with two or more SQL tables
+** pointing to the same b-tree.  If an insert occurs on one SQL table
+** and causes a BEFORE TRIGGER to do a secondary insert on the other SQL
+** table linked to the same b-tree.  If the secondary insert causes a
+** rebalance, that can change content out from under the cursor on the
+** first SQL table, violating invariants on the first insert.
+*/
+static int anotherValidCursor(BtCursor *pCur){
+  BtCursor *pOther;
+  for(pOther=pCur->pBt->pCursor; pOther; pOther=pOther->pNext){
+    if( pOther!=pCur
+     && pOther->eState==CURSOR_VALID
+     && pOther->pPage==pCur->pPage
+    ){
+      return SQLITE_CORRUPT_PAGE(pCur->pPage);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The page that pCur currently points to has just been modified in
+** some way. This function figures out if this modification means the
+** tree needs to be balanced, and if so calls the appropriate balancing
+** routine. Balancing routines are:
+**
+**   balance_quick()
+**   balance_deeper()
+**   balance_nonroot()
+*/
+static int balance(BtCursor *pCur){
+  int rc = SQLITE_OK;
+  u8 aBalanceQuickSpace[13];
+  u8 *pFree = 0;
+
+  VVA_ONLY( int balance_quick_called = 0 );
+  VVA_ONLY( int balance_deeper_called = 0 );
+
+  do {
+    int iPage;
+    MemPage *pPage = pCur->pPage;
+
+    if( NEVER(pPage->nFree<0) && btreeComputeFreeSpace(pPage) ) break;
+    if( pPage->nOverflow==0 && pPage->nFree*3<=(int)pCur->pBt->usableSize*2 ){
+      /* No rebalance required as long as:
+      **   (1) There are no overflow cells
+      **   (2) The amount of free space on the page is less than 2/3rds of
+      **       the total usable space on the page. */
+      break;
+    }else if( (iPage = pCur->iPage)==0 ){
+      if( pPage->nOverflow && (rc = anotherValidCursor(pCur))==SQLITE_OK ){
+        /* The root page of the b-tree is overfull. In this case call the
+        ** balance_deeper() function to create a new child for the root-page
+        ** and copy the current contents of the root-page to it. The
+        ** next iteration of the do-loop will balance the child page.
+        */
+        assert( balance_deeper_called==0 );
+        VVA_ONLY( balance_deeper_called++ );
+        rc = balance_deeper(pPage, &pCur->apPage[1]);
+        if( rc==SQLITE_OK ){
+          pCur->iPage = 1;
+          pCur->ix = 0;
+          pCur->aiIdx[0] = 0;
+          pCur->apPage[0] = pPage;
+          pCur->pPage = pCur->apPage[1];
+          assert( pCur->pPage->nOverflow );
+        }
+      }else{
+        break;
+      }
+    }else if( sqlite3PagerPageRefcount(pPage->pDbPage)>1 ){
+      /* The page being written is not a root page, and there is currently
+      ** more than one reference to it. This only happens if the page is one
+      ** of its own ancestor pages. Corruption. */
+      rc = SQLITE_CORRUPT_PAGE(pPage);
+    }else{
+      MemPage * const pParent = pCur->apPage[iPage-1];
+      int const iIdx = pCur->aiIdx[iPage-1];
+
+      rc = sqlite3PagerWrite(pParent->pDbPage);
+      if( rc==SQLITE_OK && pParent->nFree<0 ){
+        rc = btreeComputeFreeSpace(pParent);
+      }
+      if( rc==SQLITE_OK ){
+#ifndef SQLITE_OMIT_QUICKBALANCE
+        if( pPage->intKeyLeaf
+         && pPage->nOverflow==1
+         && pPage->aiOvfl[0]==pPage->nCell
+         && pParent->pgno!=1
+         && pParent->nCell==iIdx
+        ){
+          /* Call balance_quick() to create a new sibling of pPage on which
+          ** to store the overflow cell. balance_quick() inserts a new cell
+          ** into pParent, which may cause pParent overflow. If this
+          ** happens, the next iteration of the do-loop will balance pParent
+          ** use either balance_nonroot() or balance_deeper(). Until this
+          ** happens, the overflow cell is stored in the aBalanceQuickSpace[]
+          ** buffer.
+          **
+          ** The purpose of the following assert() is to check that only a
+          ** single call to balance_quick() is made for each call to this
+          ** function. If this were not verified, a subtle bug involving reuse
+          ** of the aBalanceQuickSpace[] might sneak in.
+          */
+          assert( balance_quick_called==0 );
+          VVA_ONLY( balance_quick_called++ );
+          rc = balance_quick(pParent, pPage, aBalanceQuickSpace);
+        }else
+#endif
+        {
+          /* In this case, call balance_nonroot() to redistribute cells
+          ** between pPage and up to 2 of its sibling pages. This involves
+          ** modifying the contents of pParent, which may cause pParent to
+          ** become overfull or underfull. The next iteration of the do-loop
+          ** will balance the parent page to correct this.
+          **
+          ** If the parent page becomes overfull, the overflow cell or cells
+          ** are stored in the pSpace buffer allocated immediately below.
+          ** A subsequent iteration of the do-loop will deal with this by
+          ** calling balance_nonroot() (balance_deeper() may be called first,
+          ** but it doesn't deal with overflow cells - just moves them to a
+          ** different page). Once this subsequent call to balance_nonroot()
+          ** has completed, it is safe to release the pSpace buffer used by
+          ** the previous call, as the overflow cell data will have been
+          ** copied either into the body of a database page or into the new
+          ** pSpace buffer passed to the latter call to balance_nonroot().
+          */
+          u8 *pSpace = sqlite3PageMalloc(pCur->pBt->pageSize);
+          rc = balance_nonroot(pParent, iIdx, pSpace, iPage==1,
+                               pCur->hints&BTREE_BULKLOAD);
+          if( pFree ){
+            /* If pFree is not NULL, it points to the pSpace buffer used
+            ** by a previous call to balance_nonroot(). Its contents are
+            ** now stored either on real database pages or within the
+            ** new pSpace buffer, so it may be safely freed here. */
+            sqlite3PageFree(pFree);
+          }
+
+          /* The pSpace buffer will be freed after the next call to
+          ** balance_nonroot(), or just before this function returns, whichever
+          ** comes first. */
+          pFree = pSpace;
+        }
+      }
+
+      pPage->nOverflow = 0;
+
+      /* The next iteration of the do-loop balances the parent page. */
+      releasePage(pPage);
+      pCur->iPage--;
+      assert( pCur->iPage>=0 );
+      pCur->pPage = pCur->apPage[pCur->iPage];
+    }
+  }while( rc==SQLITE_OK );
+
+  if( pFree ){
+    sqlite3PageFree(pFree);
+  }
+  return rc;
+}
+
+/* Overwrite content from pX into pDest.  Only do the write if the
+** content is different from what is already there.
+*/
+static int btreeOverwriteContent(
+  MemPage *pPage,           /* MemPage on which writing will occur */
+  u8 *pDest,                /* Pointer to the place to start writing */
+  const BtreePayload *pX,   /* Source of data to write */
+  int iOffset,              /* Offset of first byte to write */
+  int iAmt                  /* Number of bytes to be written */
+){
+  int nData = pX->nData - iOffset;
+  if( nData<=0 ){
+    /* Overwriting with zeros */
+    int i;
+    for(i=0; i<iAmt && pDest[i]==0; i++){}
+    if( i<iAmt ){
+      int rc = sqlite3PagerWrite(pPage->pDbPage);
+      if( rc ) return rc;
+      memset(pDest + i, 0, iAmt - i);
+    }
+  }else{
+    if( nData<iAmt ){
+      /* Mixed read data and zeros at the end.  Make a recursive call
+      ** to write the zeros then fall through to write the real data */
+      int rc = btreeOverwriteContent(pPage, pDest+nData, pX, iOffset+nData,
+                                 iAmt-nData);
+      if( rc ) return rc;
+      iAmt = nData;
+    }
+    if( memcmp(pDest, ((u8*)pX->pData) + iOffset, iAmt)!=0 ){
+      int rc = sqlite3PagerWrite(pPage->pDbPage);
+      if( rc ) return rc;
+      /* In a corrupt database, it is possible for the source and destination
+      ** buffers to overlap.  This is harmless since the database is already
+      ** corrupt but it does cause valgrind and ASAN warnings.  So use
+      ** memmove(). */
+      memmove(pDest, ((u8*)pX->pData) + iOffset, iAmt);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Overwrite the cell that cursor pCur is pointing to with fresh content
+** contained in pX.  In this variant, pCur is pointing to an overflow
+** cell.
+*/
+static SQLITE_NOINLINE int btreeOverwriteOverflowCell(
+  BtCursor *pCur,                     /* Cursor pointing to cell to overwrite */
+  const BtreePayload *pX              /* Content to write into the cell */
+){
+  int iOffset;                        /* Next byte of pX->pData to write */
+  int nTotal = pX->nData + pX->nZero; /* Total bytes of to write */
+  int rc;                             /* Return code */
+  MemPage *pPage = pCur->pPage;       /* Page being written */
+  BtShared *pBt;                      /* Btree */
+  Pgno ovflPgno;                      /* Next overflow page to write */
+  u32 ovflPageSize;                   /* Size to write on overflow page */
+
+  assert( pCur->info.nLocal<nTotal );  /* pCur is an overflow cell */
+
+  /* Overwrite the local portion first */
+  rc = btreeOverwriteContent(pPage, pCur->info.pPayload, pX,
+                             0, pCur->info.nLocal);
+  if( rc ) return rc;
+
+  /* Now overwrite the overflow pages */
+  iOffset = pCur->info.nLocal;
+  assert( nTotal>=0 );
+  assert( iOffset>=0 );
+  ovflPgno = get4byte(pCur->info.pPayload + iOffset);
+  pBt = pPage->pBt;
+  ovflPageSize = pBt->usableSize - 4;
+  do{
+    rc = btreeGetPage(pBt, ovflPgno, &pPage, 0);
+    if( rc ) return rc;
+    if( sqlite3PagerPageRefcount(pPage->pDbPage)!=1 || pPage->isInit ){
+      rc = SQLITE_CORRUPT_PAGE(pPage);
+    }else{
+      if( iOffset+ovflPageSize<(u32)nTotal ){
+        ovflPgno = get4byte(pPage->aData);
+      }else{
+        ovflPageSize = nTotal - iOffset;
+      }
+      rc = btreeOverwriteContent(pPage, pPage->aData+4, pX,
+                                 iOffset, ovflPageSize);
+    }
+    sqlite3PagerUnref(pPage->pDbPage);
+    if( rc ) return rc;
+    iOffset += ovflPageSize;
+  }while( iOffset<nTotal );
+  return SQLITE_OK;
+}
+
+/*
+** Overwrite the cell that cursor pCur is pointing to with fresh content
+** contained in pX.
+*/
+static int btreeOverwriteCell(BtCursor *pCur, const BtreePayload *pX){
+  int nTotal = pX->nData + pX->nZero; /* Total bytes of to write */
+  MemPage *pPage = pCur->pPage;       /* Page being written */
+
+  if( pCur->info.pPayload + pCur->info.nLocal > pPage->aDataEnd
+   || pCur->info.pPayload < pPage->aData + pPage->cellOffset
+  ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  if( pCur->info.nLocal==nTotal ){
+    /* The entire cell is local */
+    return btreeOverwriteContent(pPage, pCur->info.pPayload, pX,
+                                 0, pCur->info.nLocal);
+  }else{
+    /* The cell contains overflow content */
+    return btreeOverwriteOverflowCell(pCur, pX);
+  }
+}
+
+
+/*
+** Insert a new record into the BTree.  The content of the new record
+** is described by the pX object.  The pCur cursor is used only to
+** define what table the record should be inserted into, and is left
+** pointing at a random location.
+**
+** For a table btree (used for rowid tables), only the pX.nKey value of
+** the key is used. The pX.pKey value must be NULL.  The pX.nKey is the
+** rowid or INTEGER PRIMARY KEY of the row.  The pX.nData,pData,nZero fields
+** hold the content of the row.
+**
+** For an index btree (used for indexes and WITHOUT ROWID tables), the
+** key is an arbitrary byte sequence stored in pX.pKey,nKey.  The
+** pX.pData,nData,nZero fields must be zero.
+**
+** If the seekResult parameter is non-zero, then a successful call to
+** sqlite3BtreeIndexMoveto() to seek cursor pCur to (pKey,nKey) has already
+** been performed.  In other words, if seekResult!=0 then the cursor
+** is currently pointing to a cell that will be adjacent to the cell
+** to be inserted.  If seekResult<0 then pCur points to a cell that is
+** smaller then (pKey,nKey).  If seekResult>0 then pCur points to a cell
+** that is larger than (pKey,nKey).
+**
+** If seekResult==0, that means pCur is pointing at some unknown location.
+** In that case, this routine must seek the cursor to the correct insertion
+** point for (pKey,nKey) before doing the insertion.  For index btrees,
+** if pX->nMem is non-zero, then pX->aMem contains pointers to the unpacked
+** key values and pX->aMem can be used instead of pX->pKey to avoid having
+** to decode the key.
+*/
+SQLITE_PRIVATE int sqlite3BtreeInsert(
+  BtCursor *pCur,                /* Insert data into the table of this cursor */
+  const BtreePayload *pX,        /* Content of the row to be inserted */
+  int flags,                     /* True if this is likely an append */
+  int seekResult                 /* Result of prior IndexMoveto() call */
+){
+  int rc;
+  int loc = seekResult;          /* -1: before desired location  +1: after */
+  int szNew = 0;
+  int idx;
+  MemPage *pPage;
+  Btree *p = pCur->pBtree;
+  unsigned char *oldCell;
+  unsigned char *newCell = 0;
+
+  assert( (flags & (BTREE_SAVEPOSITION|BTREE_APPEND|BTREE_PREFORMAT))==flags );
+  assert( (flags & BTREE_PREFORMAT)==0 || seekResult || pCur->pKeyInfo==0 );
+
+  /* Save the positions of any other cursors open on this table.
+  **
+  ** In some cases, the call to btreeMoveto() below is a no-op. For
+  ** example, when inserting data into a table with auto-generated integer
+  ** keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the
+  ** integer key to use. It then calls this function to actually insert the
+  ** data into the intkey B-Tree. In this case btreeMoveto() recognizes
+  ** that the cursor is already where it needs to be and returns without
+  ** doing any work. To avoid thwarting these optimizations, it is important
+  ** not to clear the cursor here.
+  */
+  if( pCur->curFlags & BTCF_Multiple ){
+    rc = saveAllCursors(p->pBt, pCur->pgnoRoot, pCur);
+    if( rc ) return rc;
+    if( loc && pCur->iPage<0 ){
+      /* This can only happen if the schema is corrupt such that there is more
+      ** than one table or index with the same root page as used by the cursor.
+      ** Which can only happen if the SQLITE_NoSchemaError flag was set when
+      ** the schema was loaded. This cannot be asserted though, as a user might
+      ** set the flag, load the schema, and then unset the flag.  */
+      return SQLITE_CORRUPT_PGNO(pCur->pgnoRoot);
+    }
+  }
+
+  /* Ensure that the cursor is not in the CURSOR_FAULT state and that it
+  ** points to a valid cell.
+  */
+  if( pCur->eState>=CURSOR_REQUIRESEEK ){
+    testcase( pCur->eState==CURSOR_REQUIRESEEK );
+    testcase( pCur->eState==CURSOR_FAULT );
+    rc = moveToRoot(pCur);
+    if( rc && rc!=SQLITE_EMPTY ) return rc;
+  }
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( (pCur->curFlags & BTCF_WriteFlag)!=0
+              && p->pBt->inTransaction==TRANS_WRITE
+              && (p->pBt->btsFlags & BTS_READ_ONLY)==0 );
+  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
+
+  /* Assert that the caller has been consistent. If this cursor was opened
+  ** expecting an index b-tree, then the caller should be inserting blob
+  ** keys with no associated data. If the cursor was opened expecting an
+  ** intkey table, the caller should be inserting integer keys with a
+  ** blob of associated data.  */
+  assert( (flags & BTREE_PREFORMAT) || (pX->pKey==0)==(pCur->pKeyInfo==0) );
+
+  if( pCur->pKeyInfo==0 ){
+    assert( pX->pKey==0 );
+    /* If this is an insert into a table b-tree, invalidate any incrblob
+    ** cursors open on the row being replaced */
+    if( p->hasIncrblobCur ){
+      invalidateIncrblobCursors(p, pCur->pgnoRoot, pX->nKey, 0);
+    }
+
+    /* If BTREE_SAVEPOSITION is set, the cursor must already be pointing
+    ** to a row with the same key as the new entry being inserted.
+    */
+#ifdef SQLITE_DEBUG
+    if( flags & BTREE_SAVEPOSITION ){
+      assert( pCur->curFlags & BTCF_ValidNKey );
+      assert( pX->nKey==pCur->info.nKey );
+      assert( loc==0 );
+    }
+#endif
+
+    /* On the other hand, BTREE_SAVEPOSITION==0 does not imply
+    ** that the cursor is not pointing to a row to be overwritten.
+    ** So do a complete check.
+    */
+    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && pX->nKey==pCur->info.nKey ){
+      /* The cursor is pointing to the entry that is to be
+      ** overwritten */
+      assert( pX->nData>=0 && pX->nZero>=0 );
+      if( pCur->info.nSize!=0
+       && pCur->info.nPayload==(u32)pX->nData+pX->nZero
+      ){
+        /* New entry is the same size as the old.  Do an overwrite */
+        return btreeOverwriteCell(pCur, pX);
+      }
+      assert( loc==0 );
+    }else if( loc==0 ){
+      /* The cursor is *not* pointing to the cell to be overwritten, nor
+      ** to an adjacent cell.  Move the cursor so that it is pointing either
+      ** to the cell to be overwritten or an adjacent cell.
+      */
+      rc = sqlite3BtreeTableMoveto(pCur, pX->nKey,
+               (flags & BTREE_APPEND)!=0, &loc);
+      if( rc ) return rc;
+    }
+  }else{
+    /* This is an index or a WITHOUT ROWID table */
+
+    /* If BTREE_SAVEPOSITION is set, the cursor must already be pointing
+    ** to a row with the same key as the new entry being inserted.
+    */
+    assert( (flags & BTREE_SAVEPOSITION)==0 || loc==0 );
+
+    /* If the cursor is not already pointing either to the cell to be
+    ** overwritten, or if a new cell is being inserted, if the cursor is
+    ** not pointing to an immediately adjacent cell, then move the cursor
+    ** so that it does.
+    */
+    if( loc==0 && (flags & BTREE_SAVEPOSITION)==0 ){
+      if( pX->nMem ){
+        UnpackedRecord r;
+        r.pKeyInfo = pCur->pKeyInfo;
+        r.aMem = pX->aMem;
+        r.nField = pX->nMem;
+        r.default_rc = 0;
+        r.eqSeen = 0;
+        rc = sqlite3BtreeIndexMoveto(pCur, &r, &loc);
+      }else{
+        rc = btreeMoveto(pCur, pX->pKey, pX->nKey,
+                    (flags & BTREE_APPEND)!=0, &loc);
+      }
+      if( rc ) return rc;
+    }
+
+    /* If the cursor is currently pointing to an entry to be overwritten
+    ** and the new content is the same as as the old, then use the
+    ** overwrite optimization.
+    */
+    if( loc==0 ){
+      getCellInfo(pCur);
+      if( pCur->info.nKey==pX->nKey ){
+        BtreePayload x2;
+        x2.pData = pX->pKey;
+        x2.nData = pX->nKey;
+        x2.nZero = 0;
+        return btreeOverwriteCell(pCur, &x2);
+      }
+    }
+  }
+  assert( pCur->eState==CURSOR_VALID
+       || (pCur->eState==CURSOR_INVALID && loc) || CORRUPT_DB );
+
+  pPage = pCur->pPage;
+  assert( pPage->intKey || pX->nKey>=0 || (flags & BTREE_PREFORMAT) );
+  assert( pPage->leaf || !pPage->intKey );
+  if( pPage->nFree<0 ){
+    if( NEVER(pCur->eState>CURSOR_INVALID) ){
+     /* ^^^^^--- due to the moveToRoot() call above */
+      rc = SQLITE_CORRUPT_PAGE(pPage);
+    }else{
+      rc = btreeComputeFreeSpace(pPage);
+    }
+    if( rc ) return rc;
+  }
+
+  TRACE(("INSERT: table=%u nkey=%lld ndata=%u page=%u %s\n",
+          pCur->pgnoRoot, pX->nKey, pX->nData, pPage->pgno,
+          loc==0 ? "overwrite" : "new entry"));
+  assert( pPage->isInit || CORRUPT_DB );
+  newCell = p->pBt->pTmpSpace;
+  assert( newCell!=0 );
+  assert( BTREE_PREFORMAT==OPFLAG_PREFORMAT );
+  if( flags & BTREE_PREFORMAT ){
+    rc = SQLITE_OK;
+    szNew = p->pBt->nPreformatSize;
+    if( szNew<4 ){
+      szNew = 4;
+      newCell[3] = 0;
+    }
+    if( ISAUTOVACUUM(p->pBt) && szNew>pPage->maxLocal ){
+      CellInfo info;
+      pPage->xParseCell(pPage, newCell, &info);
+      if( info.nPayload!=info.nLocal ){
+        Pgno ovfl = get4byte(&newCell[szNew-4]);
+        ptrmapPut(p->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, &rc);
+        if( NEVER(rc) ) goto end_insert;
+      }
+    }
+  }else{
+    rc = fillInCell(pPage, newCell, pX, &szNew);
+    if( rc ) goto end_insert;
+  }
+  assert( szNew==pPage->xCellSize(pPage, newCell) );
+  assert( szNew <= MX_CELL_SIZE(p->pBt) );
+  idx = pCur->ix;
+  pCur->info.nSize = 0;
+  if( loc==0 ){
+    CellInfo info;
+    assert( idx>=0 );
+    if( idx>=pPage->nCell ){
+      return SQLITE_CORRUPT_PAGE(pPage);
+    }
+    rc = sqlite3PagerWrite(pPage->pDbPage);
+    if( rc ){
+      goto end_insert;
+    }
+    oldCell = findCell(pPage, idx);
+    if( !pPage->leaf ){
+      memcpy(newCell, oldCell, 4);
+    }
+    BTREE_CLEAR_CELL(rc, pPage, oldCell, info);
+    testcase( pCur->curFlags & BTCF_ValidOvfl );
+    invalidateOverflowCache(pCur);
+    if( info.nSize==szNew && info.nLocal==info.nPayload
+     && (!ISAUTOVACUUM(p->pBt) || szNew<pPage->minLocal)
+    ){
+      /* Overwrite the old cell with the new if they are the same size.
+      ** We could also try to do this if the old cell is smaller, then add
+      ** the leftover space to the free list.  But experiments show that
+      ** doing that is no faster then skipping this optimization and just
+      ** calling dropCell() and insertCell().
+      **
+      ** This optimization cannot be used on an autovacuum database if the
+      ** new entry uses overflow pages, as the insertCell() call below is
+      ** necessary to add the PTRMAP_OVERFLOW1 pointer-map entry.  */
+      assert( rc==SQLITE_OK ); /* clearCell never fails when nLocal==nPayload */
+      if( oldCell < pPage->aData+pPage->hdrOffset+10 ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      if( oldCell+szNew > pPage->aDataEnd ){
+        return SQLITE_CORRUPT_PAGE(pPage);
+      }
+      memcpy(oldCell, newCell, szNew);
+      return SQLITE_OK;
+    }
+    dropCell(pPage, idx, info.nSize, &rc);
+    if( rc ) goto end_insert;
+  }else if( loc<0 && pPage->nCell>0 ){
+    assert( pPage->leaf );
+    idx = ++pCur->ix;
+    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+  }else{
+    assert( pPage->leaf );
+  }
+  rc = insertCellFast(pPage, idx, newCell, szNew);
+  assert( pPage->nOverflow==0 || rc==SQLITE_OK );
+  assert( rc!=SQLITE_OK || pPage->nCell>0 || pPage->nOverflow>0 );
+
+  /* If no error has occurred and pPage has an overflow cell, call balance()
+  ** to redistribute the cells within the tree. Since balance() may move
+  ** the cursor, zero the BtCursor.info.nSize and BTCF_ValidNKey
+  ** variables.
+  **
+  ** Previous versions of SQLite called moveToRoot() to move the cursor
+  ** back to the root page as balance() used to invalidate the contents
+  ** of BtCursor.apPage[] and BtCursor.aiIdx[]. Instead of doing that,
+  ** set the cursor state to "invalid". This makes common insert operations
+  ** slightly faster.
+  **
+  ** There is a subtle but important optimization here too. When inserting
+  ** multiple records into an intkey b-tree using a single cursor (as can
+  ** happen while processing an "INSERT INTO ... SELECT" statement), it
+  ** is advantageous to leave the cursor pointing to the last entry in
+  ** the b-tree if possible. If the cursor is left pointing to the last
+  ** entry in the table, and the next row inserted has an integer key
+  ** larger than the largest existing key, it is possible to insert the
+  ** row without seeking the cursor. This can be a big performance boost.
+  */
+  if( pPage->nOverflow ){
+    assert( rc==SQLITE_OK );
+    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
+    rc = balance(pCur);
+
+    /* Must make sure nOverflow is reset to zero even if the balance()
+    ** fails. Internal data structure corruption will result otherwise.
+    ** Also, set the cursor state to invalid. This stops saveCursorPosition()
+    ** from trying to save the current position of the cursor.  */
+    pCur->pPage->nOverflow = 0;
+    pCur->eState = CURSOR_INVALID;
+    if( (flags & BTREE_SAVEPOSITION) && rc==SQLITE_OK ){
+      btreeReleaseAllCursorPages(pCur);
+      if( pCur->pKeyInfo ){
+        assert( pCur->pKey==0 );
+        pCur->pKey = sqlite3Malloc( pX->nKey );
+        if( pCur->pKey==0 ){
+          rc = SQLITE_NOMEM;
+        }else{
+          memcpy(pCur->pKey, pX->pKey, pX->nKey);
+        }
+      }
+      pCur->eState = CURSOR_REQUIRESEEK;
+      pCur->nKey = pX->nKey;
+    }
+  }
+  assert( pCur->iPage<0 || pCur->pPage->nOverflow==0 );
+
+end_insert:
+  return rc;
+}
+
+/*
+** This function is used as part of copying the current row from cursor
+** pSrc into cursor pDest. If the cursors are open on intkey tables, then
+** parameter iKey is used as the rowid value when the record is copied
+** into pDest. Otherwise, the record is copied verbatim.
+**
+** This function does not actually write the new value to cursor pDest.
+** Instead, it creates and populates any required overflow pages and
+** writes the data for the new cell into the BtShared.pTmpSpace buffer
+** for the destination database. The size of the cell, in bytes, is left
+** in BtShared.nPreformatSize. The caller completes the insertion by
+** calling sqlite3BtreeInsert() with the BTREE_PREFORMAT flag specified.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3BtreeTransferRow(BtCursor *pDest, BtCursor *pSrc, i64 iKey){
+  BtShared *pBt = pDest->pBt;
+  u8 *aOut = pBt->pTmpSpace;    /* Pointer to next output buffer */
+  const u8 *aIn;                /* Pointer to next input buffer */
+  u32 nIn;                      /* Size of input buffer aIn[] */
+  u32 nRem;                     /* Bytes of data still to copy */
+
+  getCellInfo(pSrc);
+  if( pSrc->info.nPayload<0x80 ){
+    *(aOut++) = pSrc->info.nPayload;
+  }else{
+    aOut += sqlite3PutVarint(aOut, pSrc->info.nPayload);
+  }
+  if( pDest->pKeyInfo==0 ) aOut += putVarint(aOut, iKey);
+  nIn = pSrc->info.nLocal;
+  aIn = pSrc->info.pPayload;
+  if( aIn+nIn>pSrc->pPage->aDataEnd ){
+    return SQLITE_CORRUPT_PAGE(pSrc->pPage);
+  }
+  nRem = pSrc->info.nPayload;
+  if( nIn==nRem && nIn<pDest->pPage->maxLocal ){
+    memcpy(aOut, aIn, nIn);
+    pBt->nPreformatSize = nIn + (aOut - pBt->pTmpSpace);
+    return SQLITE_OK;
+  }else{
+    int rc = SQLITE_OK;
+    Pager *pSrcPager = pSrc->pBt->pPager;
+    u8 *pPgnoOut = 0;
+    Pgno ovflIn = 0;
+    DbPage *pPageIn = 0;
+    MemPage *pPageOut = 0;
+    u32 nOut;                     /* Size of output buffer aOut[] */
+
+    nOut = btreePayloadToLocal(pDest->pPage, pSrc->info.nPayload);
+    pBt->nPreformatSize = nOut + (aOut - pBt->pTmpSpace);
+    if( nOut<pSrc->info.nPayload ){
+      pPgnoOut = &aOut[nOut];
+      pBt->nPreformatSize += 4;
+    }
+
+    if( nRem>nIn ){
+      if( aIn+nIn+4>pSrc->pPage->aDataEnd ){
+        return SQLITE_CORRUPT_PAGE(pSrc->pPage);
+      }
+      ovflIn = get4byte(&pSrc->info.pPayload[nIn]);
+    }
+
+    do {
+      nRem -= nOut;
+      do{
+        assert( nOut>0 );
+        if( nIn>0 ){
+          int nCopy = MIN(nOut, nIn);
+          memcpy(aOut, aIn, nCopy);
+          nOut -= nCopy;
+          nIn -= nCopy;
+          aOut += nCopy;
+          aIn += nCopy;
+        }
+        if( nOut>0 ){
+          sqlite3PagerUnref(pPageIn);
+          pPageIn = 0;
+          rc = sqlite3PagerGet(pSrcPager, ovflIn, &pPageIn, PAGER_GET_READONLY);
+          if( rc==SQLITE_OK ){
+            aIn = (const u8*)sqlite3PagerGetData(pPageIn);
+            ovflIn = get4byte(aIn);
+            aIn += 4;
+            nIn = pSrc->pBt->usableSize - 4;
+          }
+        }
+      }while( rc==SQLITE_OK && nOut>0 );
+
+      if( rc==SQLITE_OK && nRem>0 && ALWAYS(pPgnoOut) ){
+        Pgno pgnoNew;
+        MemPage *pNew = 0;
+        rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
+        put4byte(pPgnoOut, pgnoNew);
+        if( ISAUTOVACUUM(pBt) && pPageOut ){
+          ptrmapPut(pBt, pgnoNew, PTRMAP_OVERFLOW2, pPageOut->pgno, &rc);
+        }
+        releasePage(pPageOut);
+        pPageOut = pNew;
+        if( pPageOut ){
+          pPgnoOut = pPageOut->aData;
+          put4byte(pPgnoOut, 0);
+          aOut = &pPgnoOut[4];
+          nOut = MIN(pBt->usableSize - 4, nRem);
+        }
+      }
+    }while( nRem>0 && rc==SQLITE_OK );
+
+    releasePage(pPageOut);
+    sqlite3PagerUnref(pPageIn);
+    return rc;
+  }
+}
+
+/*
+** Delete the entry that the cursor is pointing to.
+**
+** If the BTREE_SAVEPOSITION bit of the flags parameter is zero, then
+** the cursor is left pointing at an arbitrary location after the delete.
+** But if that bit is set, then the cursor is left in a state such that
+** the next call to BtreeNext() or BtreePrev() moves it to the same row
+** as it would have been on if the call to BtreeDelete() had been omitted.
+**
+** The BTREE_AUXDELETE bit of flags indicates that is one of several deletes
+** associated with a single table entry and its indexes.  Only one of those
+** deletes is considered the "primary" delete.  The primary delete occurs
+** on a cursor that is not a BTREE_FORDELETE cursor.  All but one delete
+** operation on non-FORDELETE cursors is tagged with the AUXDELETE flag.
+** The BTREE_AUXDELETE bit is a hint that is not used by this implementation,
+** but which might be used by alternative storage engines.
+*/
+SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor *pCur, u8 flags){
+  Btree *p = pCur->pBtree;
+  BtShared *pBt = p->pBt;
+  int rc;                    /* Return code */
+  MemPage *pPage;            /* Page to delete cell from */
+  unsigned char *pCell;      /* Pointer to cell to delete */
+  int iCellIdx;              /* Index of cell to delete */
+  int iCellDepth;            /* Depth of node containing pCell */
+  CellInfo info;             /* Size of the cell being deleted */
+  u8 bPreserve;              /* Keep cursor valid.  2 for CURSOR_SKIPNEXT */
+
+  assert( cursorOwnsBtShared(pCur) );
+  assert( pBt->inTransaction==TRANS_WRITE );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
+  assert( pCur->curFlags & BTCF_WriteFlag );
+  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
+  assert( !hasReadConflicts(p, pCur->pgnoRoot) );
+  assert( (flags & ~(BTREE_SAVEPOSITION | BTREE_AUXDELETE))==0 );
+  if( pCur->eState!=CURSOR_VALID ){
+    if( pCur->eState>=CURSOR_REQUIRESEEK ){
+      rc = btreeRestoreCursorPosition(pCur);
+      assert( rc!=SQLITE_OK || CORRUPT_DB || pCur->eState==CURSOR_VALID );
+      if( rc || pCur->eState!=CURSOR_VALID ) return rc;
+    }else{
+      return SQLITE_CORRUPT_PGNO(pCur->pgnoRoot);
+    }
+  }
+  assert( pCur->eState==CURSOR_VALID );
+
+  iCellDepth = pCur->iPage;
+  iCellIdx = pCur->ix;
+  pPage = pCur->pPage;
+  if( pPage->nCell<=iCellIdx ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  pCell = findCell(pPage, iCellIdx);
+  if( pPage->nFree<0 && btreeComputeFreeSpace(pPage) ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+  if( pCell<&pPage->aCellIdx[pPage->nCell] ){
+    return SQLITE_CORRUPT_PAGE(pPage);
+  }
+
+  /* If the BTREE_SAVEPOSITION bit is on, then the cursor position must
+  ** be preserved following this delete operation. If the current delete
+  ** will cause a b-tree rebalance, then this is done by saving the cursor
+  ** key and leaving the cursor in CURSOR_REQUIRESEEK state before
+  ** returning.
+  **
+  ** If the current delete will not cause a rebalance, then the cursor
+  ** will be left in CURSOR_SKIPNEXT state pointing to the entry immediately
+  ** before or after the deleted entry.
+  **
+  ** The bPreserve value records which path is required:
+  **
+  **    bPreserve==0         Not necessary to save the cursor position
+  **    bPreserve==1         Use CURSOR_REQUIRESEEK to save the cursor position
+  **    bPreserve==2         Cursor won't move.  Set CURSOR_SKIPNEXT.
+  */
+  bPreserve = (flags & BTREE_SAVEPOSITION)!=0;
+  if( bPreserve ){
+    if( !pPage->leaf
+     || (pPage->nFree+pPage->xCellSize(pPage,pCell)+2) >
+                                                   (int)(pBt->usableSize*2/3)
+     || pPage->nCell==1  /* See dbfuzz001.test for a test case */
+    ){
+      /* A b-tree rebalance will be required after deleting this entry.
+      ** Save the cursor key.  */
+      rc = saveCursorKey(pCur);
+      if( rc ) return rc;
+    }else{
+      bPreserve = 2;
+    }
+  }
+
+  /* If the page containing the entry to delete is not a leaf page, move
+  ** the cursor to the largest entry in the tree that is smaller than
+  ** the entry being deleted. This cell will replace the cell being deleted
+  ** from the internal node. The 'previous' entry is used for this instead
+  ** of the 'next' entry, as the previous entry is always a part of the
+  ** sub-tree headed by the child page of the cell being deleted. This makes
+  ** balancing the tree following the delete operation easier.  */
+  if( !pPage->leaf ){
+    rc = sqlite3BtreePrevious(pCur, 0);
+    assert( rc!=SQLITE_DONE );
+    if( rc ) return rc;
+  }
+
+  /* Save the positions of any other cursors open on this table before
+  ** making any modifications.  */
+  if( pCur->curFlags & BTCF_Multiple ){
+    rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
+    if( rc ) return rc;
+  }
+
+  /* If this is a delete operation to remove a row from a table b-tree,
+  ** invalidate any incrblob cursors open on the row being deleted.  */
+  if( pCur->pKeyInfo==0 && p->hasIncrblobCur ){
+    invalidateIncrblobCursors(p, pCur->pgnoRoot, pCur->info.nKey, 0);
+  }
+
+  /* Make the page containing the entry to be deleted writable. Then free any
+  ** overflow pages associated with the entry and finally remove the cell
+  ** itself from within the page.  */
+  rc = sqlite3PagerWrite(pPage->pDbPage);
+  if( rc ) return rc;
+  BTREE_CLEAR_CELL(rc, pPage, pCell, info);
+  dropCell(pPage, iCellIdx, info.nSize, &rc);
+  if( rc ) return rc;
+
+  /* If the cell deleted was not located on a leaf page, then the cursor
+  ** is currently pointing to the largest entry in the sub-tree headed
+  ** by the child-page of the cell that was just deleted from an internal
+  ** node. The cell from the leaf node needs to be moved to the internal
+  ** node to replace the deleted cell.  */
+  if( !pPage->leaf ){
+    MemPage *pLeaf = pCur->pPage;
+    int nCell;
+    Pgno n;
+    unsigned char *pTmp;
+
+    if( pLeaf->nFree<0 ){
+      rc = btreeComputeFreeSpace(pLeaf);
+      if( rc ) return rc;
+    }
+    if( iCellDepth<pCur->iPage-1 ){
+      n = pCur->apPage[iCellDepth+1]->pgno;
+    }else{
+      n = pCur->pPage->pgno;
+    }
+    pCell = findCell(pLeaf, pLeaf->nCell-1);
+    if( pCell<&pLeaf->aData[4] ) return SQLITE_CORRUPT_PAGE(pLeaf);
+    nCell = pLeaf->xCellSize(pLeaf, pCell);
+    assert( MX_CELL_SIZE(pBt) >= nCell );
+    pTmp = pBt->pTmpSpace;
+    assert( pTmp!=0 );
+    rc = sqlite3PagerWrite(pLeaf->pDbPage);
+    if( rc==SQLITE_OK ){
+      rc = insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n);
+    }
+    dropCell(pLeaf, pLeaf->nCell-1, nCell, &rc);
+    if( rc ) return rc;
+  }
+
+  /* Balance the tree. If the entry deleted was located on a leaf page,
+  ** then the cursor still points to that page. In this case the first
+  ** call to balance() repairs the tree, and the if(...) condition is
+  ** never true.
+  **
+  ** Otherwise, if the entry deleted was on an internal node page, then
+  ** pCur is pointing to the leaf page from which a cell was removed to
+  ** replace the cell deleted from the internal node. This is slightly
+  ** tricky as the leaf node may be underfull, and the internal node may
+  ** be either under or overfull. In this case run the balancing algorithm
+  ** on the leaf node first. If the balance proceeds far enough up the
+  ** tree that we can be sure that any problem in the internal node has
+  ** been corrected, so be it. Otherwise, after balancing the leaf node,
+  ** walk the cursor up the tree to the internal node and balance it as
+  ** well.  */
+  assert( pCur->pPage->nOverflow==0 );
+  assert( pCur->pPage->nFree>=0 );
+  if( pCur->pPage->nFree*3<=(int)pCur->pBt->usableSize*2 ){
+    /* Optimization: If the free space is less than 2/3rds of the page,
+    ** then balance() will always be a no-op.  No need to invoke it. */
+    rc = SQLITE_OK;
+  }else{
+    rc = balance(pCur);
+  }
+  if( rc==SQLITE_OK && pCur->iPage>iCellDepth ){
+    releasePageNotNull(pCur->pPage);
+    pCur->iPage--;
+    while( pCur->iPage>iCellDepth ){
+      releasePage(pCur->apPage[pCur->iPage--]);
+    }
+    pCur->pPage = pCur->apPage[pCur->iPage];
+    rc = balance(pCur);
+  }
+
+  if( rc==SQLITE_OK ){
+    if( bPreserve>1 ){
+      assert( (pCur->iPage==iCellDepth || CORRUPT_DB) );
+      assert( pPage==pCur->pPage || CORRUPT_DB );
+      assert( (pPage->nCell>0 || CORRUPT_DB) && iCellIdx<=pPage->nCell );
+      pCur->eState = CURSOR_SKIPNEXT;
+      if( iCellIdx>=pPage->nCell ){
+        pCur->skipNext = -1;
+        pCur->ix = pPage->nCell-1;
+      }else{
+        pCur->skipNext = 1;
+      }
+    }else{
+      rc = moveToRoot(pCur);
+      if( bPreserve ){
+        btreeReleaseAllCursorPages(pCur);
+        pCur->eState = CURSOR_REQUIRESEEK;
+      }
+      if( rc==SQLITE_EMPTY ) rc = SQLITE_OK;
+    }
+  }
+  return rc;
+}
+
+/*
+** Create a new BTree table.  Write into *piTable the page
+** number for the root page of the new table.
+**
+** The type of type is determined by the flags parameter.  Only the
+** following values of flags are currently in use.  Other values for
+** flags might not work:
+**
+**     BTREE_INTKEY|BTREE_LEAFDATA     Used for SQL tables with rowid keys
+**     BTREE_ZERODATA                  Used for SQL indices
+*/
+static int btreeCreateTable(Btree *p, Pgno *piTable, int createTabFlags){
+  BtShared *pBt = p->pBt;
+  MemPage *pRoot;
+  Pgno pgnoRoot;
+  int rc;
+  int ptfFlags;          /* Page-type flags for the root page of new table */
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( pBt->inTransaction==TRANS_WRITE );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
+
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
+  if( rc ){
+    return rc;
+  }
+#else
+  if( pBt->autoVacuum ){
+    Pgno pgnoMove;      /* Move a page here to make room for the root-page */
+    MemPage *pPageMove; /* The page to move to. */
+
+    /* Creating a new table may probably require moving an existing database
+    ** to make room for the new tables root page. In case this page turns
+    ** out to be an overflow page, delete all overflow page-map caches
+    ** held by open cursors.
+    */
+    invalidateAllOverflowCache(pBt);
+
+    /* Read the value of meta[3] from the database to determine where the
+    ** root page of the new table should go. meta[3] is the largest root-page
+    ** created so far, so the new root-page is (meta[3]+1).
+    */
+    sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &pgnoRoot);
+    if( pgnoRoot>btreePagecount(pBt) ){
+      return SQLITE_CORRUPT_PGNO(pgnoRoot);
+    }
+    pgnoRoot++;
+
+    /* The new root-page may not be allocated on a pointer-map page, or the
+    ** PENDING_BYTE page.
+    */
+    while( pgnoRoot==PTRMAP_PAGENO(pBt, pgnoRoot) ||
+        pgnoRoot==PENDING_BYTE_PAGE(pBt) ){
+      pgnoRoot++;
+    }
+    assert( pgnoRoot>=3 );
+
+    /* Allocate a page. The page that currently resides at pgnoRoot will
+    ** be moved to the allocated page (unless the allocated page happens
+    ** to reside at pgnoRoot).
+    */
+    rc = allocateBtreePage(pBt, &pPageMove, &pgnoMove, pgnoRoot, BTALLOC_EXACT);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    if( pgnoMove!=pgnoRoot ){
+      /* pgnoRoot is the page that will be used for the root-page of
+      ** the new table (assuming an error did not occur). But we were
+      ** allocated pgnoMove. If required (i.e. if it was not allocated
+      ** by extending the file), the current page at position pgnoMove
+      ** is already journaled.
+      */
+      u8 eType = 0;
+      Pgno iPtrPage = 0;
+
+      /* Save the positions of any open cursors. This is required in
+      ** case they are holding a reference to an xFetch reference
+      ** corresponding to page pgnoRoot.  */
+      rc = saveAllCursors(pBt, 0, 0);
+      releasePage(pPageMove);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+
+      /* Move the page currently at pgnoRoot to pgnoMove. */
+      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = ptrmapGet(pBt, pgnoRoot, &eType, &iPtrPage);
+      if( eType==PTRMAP_ROOTPAGE || eType==PTRMAP_FREEPAGE ){
+        rc = SQLITE_CORRUPT_PGNO(pgnoRoot);
+      }
+      if( rc!=SQLITE_OK ){
+        releasePage(pRoot);
+        return rc;
+      }
+      assert( eType!=PTRMAP_ROOTPAGE );
+      assert( eType!=PTRMAP_FREEPAGE );
+      rc = relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove, 0);
+      releasePage(pRoot);
+
+      /* Obtain the page at pgnoRoot */
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = sqlite3PagerWrite(pRoot->pDbPage);
+      if( rc!=SQLITE_OK ){
+        releasePage(pRoot);
+        return rc;
+      }
+    }else{
+      pRoot = pPageMove;
+    }
+
+    /* Update the pointer-map and meta-data with the new root-page number. */
+    ptrmapPut(pBt, pgnoRoot, PTRMAP_ROOTPAGE, 0, &rc);
+    if( rc ){
+      releasePage(pRoot);
+      return rc;
+    }
+
+    /* When the new root page was allocated, page 1 was made writable in
+    ** order either to increase the database filesize, or to decrement the
+    ** freelist count.  Hence, the sqlite3BtreeUpdateMeta() call cannot fail.
+    */
+    assert( sqlite3PagerIswriteable(pBt->pPage1->pDbPage) );
+    rc = sqlite3BtreeUpdateMeta(p, 4, pgnoRoot);
+    if( NEVER(rc) ){
+      releasePage(pRoot);
+      return rc;
+    }
+
+  }else{
+    rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
+    if( rc ) return rc;
+  }
+#endif
+  assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
+  if( createTabFlags & BTREE_INTKEY ){
+    ptfFlags = PTF_INTKEY | PTF_LEAFDATA | PTF_LEAF;
+  }else{
+    ptfFlags = PTF_ZERODATA | PTF_LEAF;
+  }
+  zeroPage(pRoot, ptfFlags);
+  sqlite3PagerUnref(pRoot->pDbPage);
+  assert( (pBt->openFlags & BTREE_SINGLE)==0 || pgnoRoot==2 );
+  *piTable = pgnoRoot;
+  return SQLITE_OK;
+}
+SQLITE_PRIVATE int sqlite3BtreeCreateTable(Btree *p, Pgno *piTable, int flags){
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = btreeCreateTable(p, piTable, flags);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Erase the given database page and all its children.  Return
+** the page to the freelist.
+*/
+static int clearDatabasePage(
+  BtShared *pBt,           /* The BTree that contains the table */
+  Pgno pgno,               /* Page number to clear */
+  int freePageFlag,        /* Deallocate page if true */
+  i64 *pnChange            /* Add number of Cells freed to this counter */
+){
+  MemPage *pPage;
+  int rc;
+  unsigned char *pCell;
+  int i;
+  int hdr;
+  CellInfo info;
+
+  assert( sqlite3_mutex_held(pBt->mutex) );
+  if( pgno>btreePagecount(pBt) ){
+    return SQLITE_CORRUPT_PGNO(pgno);
+  }
+  rc = getAndInitPage(pBt, pgno, &pPage, 0);
+  if( rc ) return rc;
+  if( (pBt->openFlags & BTREE_SINGLE)==0
+   && sqlite3PagerPageRefcount(pPage->pDbPage) != (1 + (pgno==1))
+  ){
+    rc = SQLITE_CORRUPT_PAGE(pPage);
+    goto cleardatabasepage_out;
+  }
+  hdr = pPage->hdrOffset;
+  for(i=0; i<pPage->nCell; i++){
+    pCell = findCell(pPage, i);
+    if( !pPage->leaf ){
+      rc = clearDatabasePage(pBt, get4byte(pCell), 1, pnChange);
+      if( rc ) goto cleardatabasepage_out;
+    }
+    BTREE_CLEAR_CELL(rc, pPage, pCell, info);
+    if( rc ) goto cleardatabasepage_out;
+  }
+  if( !pPage->leaf ){
+    rc = clearDatabasePage(pBt, get4byte(&pPage->aData[hdr+8]), 1, pnChange);
+    if( rc ) goto cleardatabasepage_out;
+    if( pPage->intKey ) pnChange = 0;
+  }
+  if( pnChange ){
+    testcase( !pPage->intKey );
+    *pnChange += pPage->nCell;
+  }
+  if( freePageFlag ){
+    freePage(pPage, &rc);
+  }else if( (rc = sqlite3PagerWrite(pPage->pDbPage))==0 ){
+    zeroPage(pPage, pPage->aData[hdr] | PTF_LEAF);
+  }
+
+cleardatabasepage_out:
+  releasePage(pPage);
+  return rc;
+}
+
+/*
+** Delete all information from a single table in the database.  iTable is
+** the page number of the root of the table.  After this routine returns,
+** the root page is empty, but still exists.
+**
+** This routine will fail with SQLITE_LOCKED if there are any open
+** read cursors on the table.  Open write cursors are moved to the
+** root of the table.
+**
+** If pnChange is not NULL, then the integer value pointed to by pnChange
+** is incremented by the number of entries in the table.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree *p, int iTable, i64 *pnChange){
+  int rc;
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans==TRANS_WRITE );
+
+  rc = saveAllCursors(pBt, (Pgno)iTable, 0);
+
+  if( SQLITE_OK==rc ){
+    /* Invalidate all incrblob cursors open on table iTable (assuming iTable
+    ** is the root of a table b-tree - if it is not, the following call is
+    ** a no-op).  */
+    if( p->hasIncrblobCur ){
+      invalidateIncrblobCursors(p, (Pgno)iTable, 0, 1);
+    }
+    rc = clearDatabasePage(pBt, (Pgno)iTable, 0, pnChange);
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** Delete all information from the single table that pCur is open on.
+**
+** This routine only work for pCur on an ephemeral table.
+*/
+SQLITE_PRIVATE int sqlite3BtreeClearTableOfCursor(BtCursor *pCur){
+  return sqlite3BtreeClearTable(pCur->pBtree, pCur->pgnoRoot, 0);
+}
+
+/*
+** Erase all information in a table and add the root of the table to
+** the freelist.  Except, the root of the principle table (the one on
+** page 1) is never added to the freelist.
+**
+** This routine will fail with SQLITE_LOCKED if there are any open
+** cursors on the table.
+**
+** If AUTOVACUUM is enabled and the page at iTable is not the last
+** root page in the database file, then the last root page
+** in the database file is moved into the slot formerly occupied by
+** iTable and that last slot formerly occupied by the last root page
+** is added to the freelist instead of iTable.  In this say, all
+** root pages are kept at the beginning of the database file, which
+** is necessary for AUTOVACUUM to work right.  *piMoved is set to the
+** page number that used to be the last root page in the file before
+** the move.  If no page gets moved, *piMoved is set to 0.
+** The last root page is recorded in meta[3] and the value of
+** meta[3] is updated by this procedure.
+*/
+static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
+  int rc;
+  MemPage *pPage = 0;
+  BtShared *pBt = p->pBt;
+
+  assert( sqlite3BtreeHoldsMutex(p) );
+  assert( p->inTrans==TRANS_WRITE );
+  assert( iTable>=2 );
+  if( iTable>btreePagecount(pBt) ){
+    return SQLITE_CORRUPT_PGNO(iTable);
+  }
+
+  rc = sqlite3BtreeClearTable(p, iTable, 0);
+  if( rc ) return rc;
+  rc = btreeGetPage(pBt, (Pgno)iTable, &pPage, 0);
+  if( NEVER(rc) ){
+    releasePage(pPage);
+    return rc;
+  }
+
+  *piMoved = 0;
+
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  freePage(pPage, &rc);
+  releasePage(pPage);
+#else
+  if( pBt->autoVacuum ){
+    Pgno maxRootPgno;
+    sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &maxRootPgno);
+
+    if( iTable==maxRootPgno ){
+      /* If the table being dropped is the table with the largest root-page
+      ** number in the database, put the root page on the free list.
+      */
+      freePage(pPage, &rc);
+      releasePage(pPage);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+    }else{
+      /* The table being dropped does not have the largest root-page
+      ** number in the database. So move the page that does into the
+      ** gap left by the deleted root-page.
+      */
+      MemPage *pMove;
+      releasePage(pPage);
+      rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      rc = relocatePage(pBt, pMove, PTRMAP_ROOTPAGE, 0, iTable, 0);
+      releasePage(pMove);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      pMove = 0;
+      rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
+      freePage(pMove, &rc);
+      releasePage(pMove);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      *piMoved = maxRootPgno;
+    }
+
+    /* Set the new 'max-root-page' value in the database header. This
+    ** is the old value less one, less one more if that happens to
+    ** be a root-page number, less one again if that is the
+    ** PENDING_BYTE_PAGE.
+    */
+    maxRootPgno--;
+    while( maxRootPgno==PENDING_BYTE_PAGE(pBt)
+           || PTRMAP_ISPAGE(pBt, maxRootPgno) ){
+      maxRootPgno--;
+    }
+    assert( maxRootPgno!=PENDING_BYTE_PAGE(pBt) );
+
+    rc = sqlite3BtreeUpdateMeta(p, 4, maxRootPgno);
+  }else{
+    freePage(pPage, &rc);
+    releasePage(pPage);
+  }
+#endif
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree *p, int iTable, int *piMoved){
+  int rc;
+  sqlite3BtreeEnter(p);
+  rc = btreeDropTable(p, iTable, piMoved);
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+
+/*
+** This function may only be called if the b-tree connection already
+** has a read or write transaction open on the database.
+**
+** Read the meta-information out of a database file.  Meta[0]
+** is the number of free pages currently in the database.  Meta[1]
+** through meta[15] are available for use by higher layers.  Meta[0]
+** is read-only, the others are read/write.
+**
+** The schema layer numbers meta values differently.  At the schema
+** layer (and the SetCookie and ReadCookie opcodes) the number of
+** free pages is not visible.  So Cookie[0] is the same as Meta[1].
+**
+** This routine treats Meta[BTREE_DATA_VERSION] as a special case.  Instead
+** of reading the value out of the header, it instead loads the "DataVersion"
+** from the pager.  The BTREE_DATA_VERSION value is not actually stored in the
+** database file.  It is a number computed by the pager.  But its access
+** pattern is the same as header meta values, and so it is convenient to
+** read it from this routine.
+*/
+SQLITE_PRIVATE void sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
+  BtShared *pBt = p->pBt;
+
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans>TRANS_NONE );
+  assert( SQLITE_OK==querySharedCacheTableLock(p, SCHEMA_ROOT, READ_LOCK) );
+  assert( pBt->pPage1 );
+  assert( idx>=0 && idx<=15 );
+
+  if( idx==BTREE_DATA_VERSION ){
+    *pMeta = sqlite3PagerDataVersion(pBt->pPager) + p->iBDataVersion;
+  }else{
+    *pMeta = get4byte(&pBt->pPage1->aData[36 + idx*4]);
+  }
+
+  /* If auto-vacuum is disabled in this build and this is an auto-vacuum
+  ** database, mark the database as read-only.  */
+#ifdef SQLITE_OMIT_AUTOVACUUM
+  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ){
+    pBt->btsFlags |= BTS_READ_ONLY;
+  }
+#endif
+
+  sqlite3BtreeLeave(p);
+}
+
+/*
+** Write meta-information back into the database.  Meta[0] is
+** read-only and may not be written.
+*/
+SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree *p, int idx, u32 iMeta){
+  BtShared *pBt = p->pBt;
+  unsigned char *pP1;
+  int rc;
+  assert( idx>=1 && idx<=15 );
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans==TRANS_WRITE );
+  assert( pBt->pPage1!=0 );
+  pP1 = pBt->pPage1->aData;
+  rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+  if( rc==SQLITE_OK ){
+    put4byte(&pP1[36 + idx*4], iMeta);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( idx==BTREE_INCR_VACUUM ){
+      assert( pBt->autoVacuum || iMeta==0 );
+      assert( iMeta==0 || iMeta==1 );
+      pBt->incrVacuum = (u8)iMeta;
+    }
+#endif
+  }
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+/*
+** The first argument, pCur, is a cursor opened on some b-tree. Count the
+** number of entries in the b-tree and write the result to *pnEntry.
+**
+** SQLITE_OK is returned if the operation is successfully executed.
+** Otherwise, if an error is encountered (i.e. an IO error or database
+** corruption) an SQLite error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCount(sqlite3 *db, BtCursor *pCur, i64 *pnEntry){
+  i64 nEntry = 0;                      /* Value to return in *pnEntry */
+  int rc;                              /* Return code */
+
+  rc = moveToRoot(pCur);
+  if( rc==SQLITE_EMPTY ){
+    *pnEntry = 0;
+    return SQLITE_OK;
+  }
+
+  /* Unless an error occurs, the following loop runs one iteration for each
+  ** page in the B-Tree structure (not including overflow pages).
+  */
+  while( rc==SQLITE_OK && !AtomicLoad(&db->u1.isInterrupted) ){
+    int iIdx;                          /* Index of child node in parent */
+    MemPage *pPage;                    /* Current page of the b-tree */
+
+    /* If this is a leaf page or the tree is not an int-key tree, then
+    ** this page contains countable entries. Increment the entry counter
+    ** accordingly.
+    */
+    pPage = pCur->pPage;
+    if( pPage->leaf || !pPage->intKey ){
+      nEntry += pPage->nCell;
+    }
+
+    /* pPage is a leaf node. This loop navigates the cursor so that it
+    ** points to the first interior cell that it points to the parent of
+    ** the next page in the tree that has not yet been visited. The
+    ** pCur->aiIdx[pCur->iPage] value is set to the index of the parent cell
+    ** of the page, or to the number of cells in the page if the next page
+    ** to visit is the right-child of its parent.
+    **
+    ** If all pages in the tree have been visited, return SQLITE_OK to the
+    ** caller.
+    */
+    if( pPage->leaf ){
+      do {
+        if( pCur->iPage==0 ){
+          /* All pages of the b-tree have been visited. Return successfully. */
+          *pnEntry = nEntry;
+          return moveToRoot(pCur);
+        }
+        moveToParent(pCur);
+      }while ( pCur->ix>=pCur->pPage->nCell );
+
+      pCur->ix++;
+      pPage = pCur->pPage;
+    }
+
+    /* Descend to the child node of the cell that the cursor currently
+    ** points at. This is the right-child if (iIdx==pPage->nCell).
+    */
+    iIdx = pCur->ix;
+    if( iIdx==pPage->nCell ){
+      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
+    }else{
+      rc = moveToChild(pCur, get4byte(findCell(pPage, iIdx)));
+    }
+  }
+
+  /* An error has occurred. Return an error code. */
+  return rc;
+}
+
+/*
+** Return the pager associated with a BTree.  This routine is used for
+** testing and debugging only.
+*/
+SQLITE_PRIVATE Pager *sqlite3BtreePager(Btree *p){
+  return p->pBt->pPager;
+}
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** Record an OOM error during integrity_check
+*/
+static void checkOom(IntegrityCk *pCheck){
+  pCheck->rc = SQLITE_NOMEM;
+  pCheck->mxErr = 0;  /* Causes integrity_check processing to stop */
+  if( pCheck->nErr==0 ) pCheck->nErr++;
+}
+
+/*
+** Invoke the progress handler, if appropriate.  Also check for an
+** interrupt.
+*/
+static void checkProgress(IntegrityCk *pCheck){
+  sqlite3 *db = pCheck->db;
+  if( AtomicLoad(&db->u1.isInterrupted) ){
+    pCheck->rc = SQLITE_INTERRUPT;
+    pCheck->nErr++;
+    pCheck->mxErr = 0;
+  }
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  if( db->xProgress ){
+    assert( db->nProgressOps>0 );
+    pCheck->nStep++;
+    if( (pCheck->nStep % db->nProgressOps)==0
+     && db->xProgress(db->pProgressArg)
+    ){
+      pCheck->rc = SQLITE_INTERRUPT;
+      pCheck->nErr++;
+      pCheck->mxErr = 0;
+    }
+  }
+#endif
+}
+
+/*
+** Append a message to the error message string.
+*/
+static void checkAppendMsg(
+  IntegrityCk *pCheck,
+  const char *zFormat,
+  ...
+){
+  va_list ap;
+  checkProgress(pCheck);
+  if( !pCheck->mxErr ) return;
+  pCheck->mxErr--;
+  pCheck->nErr++;
+  va_start(ap, zFormat);
+  if( pCheck->errMsg.nChar ){
+    sqlite3_str_append(&pCheck->errMsg, "\n", 1);
+  }
+  if( pCheck->zPfx ){
+    sqlite3_str_appendf(&pCheck->errMsg, pCheck->zPfx,
+                        pCheck->v0, pCheck->v1, pCheck->v2);
+  }
+  sqlite3_str_vappendf(&pCheck->errMsg, zFormat, ap);
+  va_end(ap);
+  if( pCheck->errMsg.accError==SQLITE_NOMEM ){
+    checkOom(pCheck);
+  }
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+
+/*
+** Return non-zero if the bit in the IntegrityCk.aPgRef[] array that
+** corresponds to page iPg is already set.
+*/
+static int getPageReferenced(IntegrityCk *pCheck, Pgno iPg){
+  assert( pCheck->aPgRef!=0 );
+  assert( iPg<=pCheck->nCkPage && sizeof(pCheck->aPgRef[0])==1 );
+  return (pCheck->aPgRef[iPg/8] & (1 << (iPg & 0x07)));
+}
+
+/*
+** Set the bit in the IntegrityCk.aPgRef[] array that corresponds to page iPg.
+*/
+static void setPageReferenced(IntegrityCk *pCheck, Pgno iPg){
+  assert( pCheck->aPgRef!=0 );
+  assert( iPg<=pCheck->nCkPage && sizeof(pCheck->aPgRef[0])==1 );
+  pCheck->aPgRef[iPg/8] |= (1 << (iPg & 0x07));
+}
+
+
+/*
+** Add 1 to the reference count for page iPage.  If this is the second
+** reference to the page, add an error message to pCheck->zErrMsg.
+** Return 1 if there are 2 or more references to the page and 0 if
+** if this is the first reference to the page.
+**
+** Also check that the page number is in bounds.
+*/
+static int checkRef(IntegrityCk *pCheck, Pgno iPage){
+  if( iPage>pCheck->nCkPage || iPage==0 ){
+    checkAppendMsg(pCheck, "invalid page number %u", iPage);
+    return 1;
+  }
+  if( getPageReferenced(pCheck, iPage) ){
+    checkAppendMsg(pCheck, "2nd reference to page %u", iPage);
+    return 1;
+  }
+  setPageReferenced(pCheck, iPage);
+  return 0;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Check that the entry in the pointer-map for page iChild maps to
+** page iParent, pointer type ptrType. If not, append an error message
+** to pCheck.
+*/
+static void checkPtrmap(
+  IntegrityCk *pCheck,   /* Integrity check context */
+  Pgno iChild,           /* Child page number */
+  u8 eType,              /* Expected pointer map type */
+  Pgno iParent           /* Expected pointer map parent page number */
+){
+  int rc;
+  u8 ePtrmapType;
+  Pgno iPtrmapParent;
+
+  rc = ptrmapGet(pCheck->pBt, iChild, &ePtrmapType, &iPtrmapParent);
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ) checkOom(pCheck);
+    checkAppendMsg(pCheck, "Failed to read ptrmap key=%u", iChild);
+    return;
+  }
+
+  if( ePtrmapType!=eType || iPtrmapParent!=iParent ){
+    checkAppendMsg(pCheck,
+      "Bad ptr map entry key=%u expected=(%u,%u) got=(%u,%u)",
+      iChild, eType, iParent, ePtrmapType, iPtrmapParent);
+  }
+}
+#endif
+
+/*
+** Check the integrity of the freelist or of an overflow page list.
+** Verify that the number of pages on the list is N.
+*/
+static void checkList(
+  IntegrityCk *pCheck,  /* Integrity checking context */
+  int isFreeList,       /* True for a freelist.  False for overflow page list */
+  Pgno iPage,           /* Page number for first page in the list */
+  u32 N                 /* Expected number of pages in the list */
+){
+  int i;
+  u32 expected = N;
+  int nErrAtStart = pCheck->nErr;
+  while( iPage!=0 && pCheck->mxErr ){
+    DbPage *pOvflPage;
+    unsigned char *pOvflData;
+    if( checkRef(pCheck, iPage) ) break;
+    N--;
+    if( sqlite3PagerGet(pCheck->pPager, (Pgno)iPage, &pOvflPage, 0) ){
+      checkAppendMsg(pCheck, "failed to get page %u", iPage);
+      break;
+    }
+    pOvflData = (unsigned char *)sqlite3PagerGetData(pOvflPage);
+    if( isFreeList ){
+      u32 n = (u32)get4byte(&pOvflData[4]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pCheck->pBt->autoVacuum ){
+        checkPtrmap(pCheck, iPage, PTRMAP_FREEPAGE, 0);
+      }
+#endif
+      if( n>pCheck->pBt->usableSize/4-2 ){
+        checkAppendMsg(pCheck,
+           "freelist leaf count too big on page %u", iPage);
+        N--;
+      }else{
+        for(i=0; i<(int)n; i++){
+          Pgno iFreePage = get4byte(&pOvflData[8+i*4]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+          if( pCheck->pBt->autoVacuum ){
+            checkPtrmap(pCheck, iFreePage, PTRMAP_FREEPAGE, 0);
+          }
+#endif
+          checkRef(pCheck, iFreePage);
+        }
+        N -= n;
+      }
+    }
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    else{
+      /* If this database supports auto-vacuum and iPage is not the last
+      ** page in this overflow list, check that the pointer-map entry for
+      ** the following page matches iPage.
+      */
+      if( pCheck->pBt->autoVacuum && N>0 ){
+        i = get4byte(pOvflData);
+        checkPtrmap(pCheck, i, PTRMAP_OVERFLOW2, iPage);
+      }
+    }
+#endif
+    iPage = get4byte(pOvflData);
+    sqlite3PagerUnref(pOvflPage);
+  }
+  if( N && nErrAtStart==pCheck->nErr ){
+    checkAppendMsg(pCheck,
+      "%s is %u but should be %u",
+      isFreeList ? "size" : "overflow list length",
+      expected-N, expected);
+  }
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+/*
+** An implementation of a min-heap.
+**
+** aHeap[0] is the number of elements on the heap.  aHeap[1] is the
+** root element.  The daughter nodes of aHeap[N] are aHeap[N*2]
+** and aHeap[N*2+1].
+**
+** The heap property is this:  Every node is less than or equal to both
+** of its daughter nodes.  A consequence of the heap property is that the
+** root node aHeap[1] is always the minimum value currently in the heap.
+**
+** The btreeHeapInsert() routine inserts an unsigned 32-bit number onto
+** the heap, preserving the heap property.  The btreeHeapPull() routine
+** removes the root element from the heap (the minimum value in the heap)
+** and then moves other nodes around as necessary to preserve the heap
+** property.
+**
+** This heap is used for cell overlap and coverage testing.  Each u32
+** entry represents the span of a cell or freeblock on a btree page.
+** The upper 16 bits are the index of the first byte of a range and the
+** lower 16 bits are the index of the last byte of that range.
+*/
+static void btreeHeapInsert(u32 *aHeap, u32 x){
+  u32 j, i;
+  assert( aHeap!=0 );
+  i = ++aHeap[0];
+  aHeap[i] = x;
+  while( (j = i/2)>0 && aHeap[j]>aHeap[i] ){
+    x = aHeap[j];
+    aHeap[j] = aHeap[i];
+    aHeap[i] = x;
+    i = j;
+  }
+}
+static int btreeHeapPull(u32 *aHeap, u32 *pOut){
+  u32 j, i, x;
+  if( (x = aHeap[0])==0 ) return 0;
+  *pOut = aHeap[1];
+  aHeap[1] = aHeap[x];
+  aHeap[x] = 0xffffffff;
+  aHeap[0]--;
+  i = 1;
+  while( (j = i*2)<=aHeap[0] ){
+    if( aHeap[j]>aHeap[j+1] ) j++;
+    if( aHeap[i]<aHeap[j] ) break;
+    x = aHeap[i];
+    aHeap[i] = aHeap[j];
+    aHeap[j] = x;
+    i = j;
+  }
+  return 1;
+}
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** Do various sanity checks on a single page of a tree.  Return
+** the tree depth.  Root pages return 0.  Parents of root pages
+** return 1, and so forth.
+**
+** These checks are done:
+**
+**      1.  Make sure that cells and freeblocks do not overlap
+**          but combine to completely cover the page.
+**      2.  Make sure integer cell keys are in order.
+**      3.  Check the integrity of overflow pages.
+**      4.  Recursively call checkTreePage on all children.
+**      5.  Verify that the depth of all children is the same.
+*/
+static int checkTreePage(
+  IntegrityCk *pCheck,  /* Context for the sanity check */
+  Pgno iPage,           /* Page number of the page to check */
+  i64 *piMinKey,        /* Write minimum integer primary key here */
+  i64 maxKey            /* Error if integer primary key greater than this */
+){
+  MemPage *pPage = 0;      /* The page being analyzed */
+  int i;                   /* Loop counter */
+  int rc;                  /* Result code from subroutine call */
+  int depth = -1, d2;      /* Depth of a subtree */
+  int pgno;                /* Page number */
+  int nFrag;               /* Number of fragmented bytes on the page */
+  int hdr;                 /* Offset to the page header */
+  int cellStart;           /* Offset to the start of the cell pointer array */
+  int nCell;               /* Number of cells */
+  int doCoverageCheck = 1; /* True if cell coverage checking should be done */
+  int keyCanBeEqual = 1;   /* True if IPK can be equal to maxKey
+                           ** False if IPK must be strictly less than maxKey */
+  u8 *data;                /* Page content */
+  u8 *pCell;               /* Cell content */
+  u8 *pCellIdx;            /* Next element of the cell pointer array */
+  BtShared *pBt;           /* The BtShared object that owns pPage */
+  u32 pc;                  /* Address of a cell */
+  u32 usableSize;          /* Usable size of the page */
+  u32 contentOffset;       /* Offset to the start of the cell content area */
+  u32 *heap = 0;           /* Min-heap used for checking cell coverage */
+  u32 x, prev = 0;         /* Next and previous entry on the min-heap */
+  const char *saved_zPfx = pCheck->zPfx;
+  int saved_v1 = pCheck->v1;
+  int saved_v2 = pCheck->v2;
+  u8 savedIsInit = 0;
+
+  /* Check that the page exists
+  */
+  checkProgress(pCheck);
+  if( pCheck->mxErr==0 ) goto end_of_check;
+  pBt = pCheck->pBt;
+  usableSize = pBt->usableSize;
+  if( iPage==0 ) return 0;
+  if( checkRef(pCheck, iPage) ) return 0;
+  pCheck->zPfx = "Tree %u page %u: ";
+  pCheck->v1 = iPage;
+  if( (rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0 ){
+    checkAppendMsg(pCheck,
+       "unable to get the page. error code=%d", rc);
+    if( rc==SQLITE_IOERR_NOMEM ) pCheck->rc = SQLITE_NOMEM;
+    goto end_of_check;
+  }
+
+  /* Clear MemPage.isInit to make sure the corruption detection code in
+  ** btreeInitPage() is executed.  */
+  savedIsInit = pPage->isInit;
+  pPage->isInit = 0;
+  if( (rc = btreeInitPage(pPage))!=0 ){
+    assert( rc==SQLITE_CORRUPT );  /* The only possible error from InitPage */
+    checkAppendMsg(pCheck,
+                   "btreeInitPage() returns error code %d", rc);
+    goto end_of_check;
+  }
+  if( (rc = btreeComputeFreeSpace(pPage))!=0 ){
+    assert( rc==SQLITE_CORRUPT );
+    checkAppendMsg(pCheck, "free space corruption", rc);
+    goto end_of_check;
+  }
+  data = pPage->aData;
+  hdr = pPage->hdrOffset;
+
+  /* Set up for cell analysis */
+  pCheck->zPfx = "Tree %u page %u cell %u: ";
+  contentOffset = get2byteNotZero(&data[hdr+5]);
+  assert( contentOffset<=usableSize );  /* Enforced by btreeInitPage() */
+
+  /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the
+  ** number of cells on the page. */
+  nCell = get2byte(&data[hdr+3]);
+  assert( pPage->nCell==nCell );
+  if( pPage->leaf || pPage->intKey==0 ){
+    pCheck->nRow += nCell;
+  }
+
+  /* EVIDENCE-OF: R-23882-45353 The cell pointer array of a b-tree page
+  ** immediately follows the b-tree page header. */
+  cellStart = hdr + 12 - 4*pPage->leaf;
+  assert( pPage->aCellIdx==&data[cellStart] );
+  pCellIdx = &data[cellStart + 2*(nCell-1)];
+
+  if( !pPage->leaf ){
+    /* Analyze the right-child page of internal pages */
+    pgno = get4byte(&data[hdr+8]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pBt->autoVacuum ){
+      pCheck->zPfx = "Tree %u page %u right child: ";
+      checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage);
+    }
+#endif
+    depth = checkTreePage(pCheck, pgno, &maxKey, maxKey);
+    keyCanBeEqual = 0;
+  }else{
+    /* For leaf pages, the coverage check will occur in the same loop
+    ** as the other cell checks, so initialize the heap.  */
+    heap = pCheck->heap;
+    heap[0] = 0;
+  }
+
+  /* EVIDENCE-OF: R-02776-14802 The cell pointer array consists of K 2-byte
+  ** integer offsets to the cell contents. */
+  for(i=nCell-1; i>=0 && pCheck->mxErr; i--){
+    CellInfo info;
+
+    /* Check cell size */
+    pCheck->v2 = i;
+    assert( pCellIdx==&data[cellStart + i*2] );
+    pc = get2byteAligned(pCellIdx);
+    pCellIdx -= 2;
+    if( pc<contentOffset || pc>usableSize-4 ){
+      checkAppendMsg(pCheck, "Offset %u out of range %u..%u",
+                             pc, contentOffset, usableSize-4);
+      doCoverageCheck = 0;
+      continue;
+    }
+    pCell = &data[pc];
+    pPage->xParseCell(pPage, pCell, &info);
+    if( pc+info.nSize>usableSize ){
+      checkAppendMsg(pCheck, "Extends off end of page");
+      doCoverageCheck = 0;
+      continue;
+    }
+
+    /* Check for integer primary key out of range */
+    if( pPage->intKey ){
+      if( keyCanBeEqual ? (info.nKey > maxKey) : (info.nKey >= maxKey) ){
+        checkAppendMsg(pCheck, "Rowid %lld out of order", info.nKey);
+      }
+      maxKey = info.nKey;
+      keyCanBeEqual = 0;     /* Only the first key on the page may ==maxKey */
+    }
+
+    /* Check the content overflow list */
+    if( info.nPayload>info.nLocal ){
+      u32 nPage;       /* Number of pages on the overflow chain */
+      Pgno pgnoOvfl;   /* First page of the overflow chain */
+      assert( pc + info.nSize - 4 <= usableSize );
+      nPage = (info.nPayload - info.nLocal + usableSize - 5)/(usableSize - 4);
+      pgnoOvfl = get4byte(&pCell[info.nSize - 4]);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pBt->autoVacuum ){
+        checkPtrmap(pCheck, pgnoOvfl, PTRMAP_OVERFLOW1, iPage);
+      }
+#endif
+      checkList(pCheck, 0, pgnoOvfl, nPage);
+    }
+
+    if( !pPage->leaf ){
+      /* Check sanity of left child page for internal pages */
+      pgno = get4byte(pCell);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pBt->autoVacuum ){
+        checkPtrmap(pCheck, pgno, PTRMAP_BTREE, iPage);
+      }
+#endif
+      d2 = checkTreePage(pCheck, pgno, &maxKey, maxKey);
+      keyCanBeEqual = 0;
+      if( d2!=depth ){
+        checkAppendMsg(pCheck, "Child page depth differs");
+        depth = d2;
+      }
+    }else{
+      /* Populate the coverage-checking heap for leaf pages */
+      btreeHeapInsert(heap, (pc<<16)|(pc+info.nSize-1));
+    }
+  }
+  *piMinKey = maxKey;
+
+  /* Check for complete coverage of the page
+  */
+  pCheck->zPfx = 0;
+  if( doCoverageCheck && pCheck->mxErr>0 ){
+    /* For leaf pages, the min-heap has already been initialized and the
+    ** cells have already been inserted.  But for internal pages, that has
+    ** not yet been done, so do it now */
+    if( !pPage->leaf ){
+      heap = pCheck->heap;
+      heap[0] = 0;
+      for(i=nCell-1; i>=0; i--){
+        u32 size;
+        pc = get2byteAligned(&data[cellStart+i*2]);
+        size = pPage->xCellSize(pPage, &data[pc]);
+        btreeHeapInsert(heap, (pc<<16)|(pc+size-1));
+      }
+    }
+    assert( heap!=0 );
+    /* Add the freeblocks to the min-heap
+    **
+    ** EVIDENCE-OF: R-20690-50594 The second field of the b-tree page header
+    ** is the offset of the first freeblock, or zero if there are no
+    ** freeblocks on the page.
+    */
+    i = get2byte(&data[hdr+1]);
+    while( i>0 ){
+      int size, j;
+      assert( (u32)i<=usableSize-4 ); /* Enforced by btreeComputeFreeSpace() */
+      size = get2byte(&data[i+2]);
+      assert( (u32)(i+size)<=usableSize ); /* due to btreeComputeFreeSpace() */
+      btreeHeapInsert(heap, (((u32)i)<<16)|(i+size-1));
+      /* EVIDENCE-OF: R-58208-19414 The first 2 bytes of a freeblock are a
+      ** big-endian integer which is the offset in the b-tree page of the next
+      ** freeblock in the chain, or zero if the freeblock is the last on the
+      ** chain. */
+      j = get2byte(&data[i]);
+      /* EVIDENCE-OF: R-06866-39125 Freeblocks are always connected in order of
+      ** increasing offset. */
+      assert( j==0 || j>i+size );     /* Enforced by btreeComputeFreeSpace() */
+      assert( (u32)j<=usableSize-4 ); /* Enforced by btreeComputeFreeSpace() */
+      i = j;
+    }
+    /* Analyze the min-heap looking for overlap between cells and/or
+    ** freeblocks, and counting the number of untracked bytes in nFrag.
+    **
+    ** Each min-heap entry is of the form:    (start_address<<16)|end_address.
+    ** There is an implied first entry the covers the page header, the cell
+    ** pointer index, and the gap between the cell pointer index and the start
+    ** of cell content.
+    **
+    ** The loop below pulls entries from the min-heap in order and compares
+    ** the start_address against the previous end_address.  If there is an
+    ** overlap, that means bytes are used multiple times.  If there is a gap,
+    ** that gap is added to the fragmentation count.
+    */
+    nFrag = 0;
+    prev = contentOffset - 1;   /* Implied first min-heap entry */
+    while( btreeHeapPull(heap,&x) ){
+      if( (prev&0xffff)>=(x>>16) ){
+        checkAppendMsg(pCheck,
+          "Multiple uses for byte %u of page %u", x>>16, iPage);
+        break;
+      }else{
+        nFrag += (x>>16) - (prev&0xffff) - 1;
+        prev = x;
+      }
+    }
+    nFrag += usableSize - (prev&0xffff) - 1;
+    /* EVIDENCE-OF: R-43263-13491 The total number of bytes in all fragments
+    ** is stored in the fifth field of the b-tree page header.
+    ** EVIDENCE-OF: R-07161-27322 The one-byte integer at offset 7 gives the
+    ** number of fragmented free bytes within the cell content area.
+    */
+    if( heap[0]==0 && nFrag!=data[hdr+7] ){
+      checkAppendMsg(pCheck,
+          "Fragmentation of %u bytes reported as %u on page %u",
+          nFrag, data[hdr+7], iPage);
+    }
+  }
+
+end_of_check:
+  if( !doCoverageCheck ) pPage->isInit = savedIsInit;
+  releasePage(pPage);
+  pCheck->zPfx = saved_zPfx;
+  pCheck->v1 = saved_v1;
+  pCheck->v2 = saved_v2;
+  return depth+1;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/*
+** This routine does a complete check of the given BTree file.  aRoot[] is
+** an array of pages numbers were each page number is the root page of
+** a table.  nRoot is the number of entries in aRoot.
+**
+** A read-only or read-write transaction must be opened before calling
+** this function.
+**
+** Write the number of error seen in *pnErr.  Except for some memory
+** allocation errors,  an error message held in memory obtained from
+** malloc is returned if *pnErr is non-zero.  If *pnErr==0 then NULL is
+** returned.  If a memory allocation error occurs, NULL is returned.
+**
+** If the first entry in aRoot[] is 0, that indicates that the list of
+** root pages is incomplete.  This is a "partial integrity-check".  This
+** happens when performing an integrity check on a single table.  The
+** zero is skipped, of course.  But in addition, the freelist checks
+** and the checks to make sure every page is referenced are also skipped,
+** since obviously it is not possible to know which pages are covered by
+** the unverified btrees.  Except, if aRoot[1] is 1, then the freelist
+** checks are still performed.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIntegrityCheck(
+  sqlite3 *db,  /* Database connection that is running the check */
+  Btree *p,     /* The btree to be checked */
+  Pgno *aRoot,  /* An array of root pages numbers for individual trees */
+  Mem *aCnt,    /* Memory cells to write counts for each tree to */
+  int nRoot,    /* Number of entries in aRoot[] */
+  int mxErr,    /* Stop reporting errors after this many */
+  int *pnErr,   /* OUT: Write number of errors seen to this variable */
+  char **pzOut  /* OUT: Write the error message string here */
+){
+  Pgno i;
+  IntegrityCk sCheck;
+  BtShared *pBt = p->pBt;
+  u64 savedDbFlags = pBt->db->flags;
+  char zErr[100];
+  int bPartial = 0;            /* True if not checking all btrees */
+  int bCkFreelist = 1;         /* True to scan the freelist */
+  VVA_ONLY( int nRef );
+
+  assert( nRoot>0 );
+  assert( aCnt!=0 );
+
+  /* aRoot[0]==0 means this is a partial check */
+  if( aRoot[0]==0 ){
+    assert( nRoot>1 );
+    bPartial = 1;
+    if( aRoot[1]!=1 ) bCkFreelist = 0;
+  }
+
+  sqlite3BtreeEnter(p);
+  assert( p->inTrans>TRANS_NONE && pBt->inTransaction>TRANS_NONE );
+  VVA_ONLY( nRef = sqlite3PagerRefcount(pBt->pPager) );
+  assert( nRef>=0 );
+  memset(&sCheck, 0, sizeof(sCheck));
+  sCheck.db = db;
+  sCheck.pBt = pBt;
+  sCheck.pPager = pBt->pPager;
+  sCheck.nCkPage = btreePagecount(sCheck.pBt);
+  sCheck.mxErr = mxErr;
+  sqlite3StrAccumInit(&sCheck.errMsg, 0, zErr, sizeof(zErr), SQLITE_MAX_LENGTH);
+  sCheck.errMsg.printfFlags = SQLITE_PRINTF_INTERNAL;
+  if( sCheck.nCkPage==0 ){
+    goto integrity_ck_cleanup;
+  }
+
+  sCheck.aPgRef = sqlite3MallocZero((sCheck.nCkPage / 8)+ 1);
+  if( !sCheck.aPgRef ){
+    checkOom(&sCheck);
+    goto integrity_ck_cleanup;
+  }
+  sCheck.heap = (u32*)sqlite3PageMalloc( pBt->pageSize );
+  if( sCheck.heap==0 ){
+    checkOom(&sCheck);
+    goto integrity_ck_cleanup;
+  }
+
+  i = PENDING_BYTE_PAGE(pBt);
+  if( i<=sCheck.nCkPage ) setPageReferenced(&sCheck, i);
+
+  /* Check the integrity of the freelist
+  */
+  if( bCkFreelist ){
+    sCheck.zPfx = "Freelist: ";
+    checkList(&sCheck, 1, get4byte(&pBt->pPage1->aData[32]),
+              get4byte(&pBt->pPage1->aData[36]));
+    sCheck.zPfx = 0;
+  }
+
+  /* Check all the tables.
+  */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  if( !bPartial ){
+    if( pBt->autoVacuum ){
+      Pgno mx = 0;
+      Pgno mxInHdr;
+      for(i=0; (int)i<nRoot; i++) if( mx<aRoot[i] ) mx = aRoot[i];
+      mxInHdr = get4byte(&pBt->pPage1->aData[52]);
+      if( mx!=mxInHdr ){
+        checkAppendMsg(&sCheck,
+          "max rootpage (%u) disagrees with header (%u)",
+          mx, mxInHdr
+        );
+      }
+    }else if( get4byte(&pBt->pPage1->aData[64])!=0 ){
+      checkAppendMsg(&sCheck,
+        "incremental_vacuum enabled with a max rootpage of zero"
+      );
+    }
+  }
+#endif
+  testcase( pBt->db->flags & SQLITE_CellSizeCk );
+  pBt->db->flags &= ~(u64)SQLITE_CellSizeCk;
+  for(i=0; (int)i<nRoot && sCheck.mxErr; i++){
+    sCheck.nRow = 0;
+    if( aRoot[i] ){
+      i64 notUsed;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+      if( pBt->autoVacuum && aRoot[i]>1 && !bPartial ){
+        checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0);
+      }
+#endif
+      sCheck.v0 = aRoot[i];
+      checkTreePage(&sCheck, aRoot[i], ¬Used, LARGEST_INT64);
+    }
+    sqlite3MemSetArrayInt64(aCnt, i, sCheck.nRow);
+  }
+  pBt->db->flags = savedDbFlags;
+
+  /* Make sure every page in the file is referenced
+  */
+  if( !bPartial ){
+    for(i=1; i<=sCheck.nCkPage && sCheck.mxErr; i++){
+#ifdef SQLITE_OMIT_AUTOVACUUM
+      if( getPageReferenced(&sCheck, i)==0 ){
+        checkAppendMsg(&sCheck, "Page %u: never used", i);
+      }
+#else
+      /* If the database supports auto-vacuum, make sure no tables contain
+      ** references to pointer-map pages.
+      */
+      if( getPageReferenced(&sCheck, i)==0 &&
+         (PTRMAP_PAGENO(pBt, i)!=i || !pBt->autoVacuum) ){
+        checkAppendMsg(&sCheck, "Page %u: never used", i);
+      }
+      if( getPageReferenced(&sCheck, i)!=0 &&
+         (PTRMAP_PAGENO(pBt, i)==i && pBt->autoVacuum) ){
+        checkAppendMsg(&sCheck, "Page %u: pointer map referenced", i);
+      }
+#endif
+    }
+  }
+
+  /* Clean  up and report errors.
+  */
+integrity_ck_cleanup:
+  sqlite3PageFree(sCheck.heap);
+  sqlite3_free(sCheck.aPgRef);
+  *pnErr = sCheck.nErr;
+  if( sCheck.nErr==0 ){
+    sqlite3_str_reset(&sCheck.errMsg);
+    *pzOut = 0;
+  }else{
+    *pzOut = sqlite3StrAccumFinish(&sCheck.errMsg);
+  }
+  /* Make sure this analysis did not leave any unref() pages. */
+  assert( nRef==sqlite3PagerRefcount(pBt->pPager) );
+  sqlite3BtreeLeave(p);
+  return sCheck.rc;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+/*
+** Return the full pathname of the underlying database file.  Return
+** an empty string if the database is in-memory or a TEMP database.
+**
+** The pager filename is invariant as long as the pager is
+** open so it is safe to access without the BtShared mutex.
+*/
+SQLITE_PRIVATE const char *sqlite3BtreeGetFilename(Btree *p){
+  assert( p->pBt->pPager!=0 );
+  return sqlite3PagerFilename(p->pBt->pPager, 1);
+}
+
+/*
+** Return the pathname of the journal file for this database. The return
+** value of this routine is the same regardless of whether the journal file
+** has been created or not.
+**
+** The pager journal filename is invariant as long as the pager is
+** open so it is safe to access without the BtShared mutex.
+*/
+SQLITE_PRIVATE const char *sqlite3BtreeGetJournalname(Btree *p){
+  assert( p->pBt->pPager!=0 );
+  return sqlite3PagerJournalname(p->pBt->pPager);
+}
+
+/*
+** Return one of SQLITE_TXN_NONE, SQLITE_TXN_READ, or SQLITE_TXN_WRITE
+** to describe the current transaction state of Btree p.
+*/
+SQLITE_PRIVATE int sqlite3BtreeTxnState(Btree *p){
+  assert( p==0 || sqlite3_mutex_held(p->db->mutex) );
+  return p ? p->inTrans : 0;
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** Run a checkpoint on the Btree passed as the first argument.
+**
+** Return SQLITE_LOCKED if this or any other connection has an open
+** transaction on the shared-cache the argument Btree is connected to.
+**
+** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCheckpoint(Btree *p, int eMode, int *pnLog, int *pnCkpt){
+  int rc = SQLITE_OK;
+  if( p ){
+    BtShared *pBt = p->pBt;
+    sqlite3BtreeEnter(p);
+    if( pBt->inTransaction!=TRANS_NONE ){
+      rc = SQLITE_LOCKED;
+    }else{
+      rc = sqlite3PagerCheckpoint(pBt->pPager, p->db, eMode, pnLog, pnCkpt);
+    }
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+#endif
+
+/*
+** Return true if there is currently a backup running on Btree p.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIsInBackup(Btree *p){
+  assert( p );
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  return p->nBackup!=0;
+}
+
+/*
+** This function returns a pointer to a blob of memory associated with
+** a single shared-btree. The memory is used by client code for its own
+** purposes (for example, to store a high-level schema associated with
+** the shared-btree). The btree layer manages reference counting issues.
+**
+** The first time this is called on a shared-btree, nBytes bytes of memory
+** are allocated, zeroed, and returned to the caller. For each subsequent
+** call the nBytes parameter is ignored and a pointer to the same blob
+** of memory returned.
+**
+** If the nBytes parameter is 0 and the blob of memory has not yet been
+** allocated, a null pointer is returned. If the blob has already been
+** allocated, it is returned as normal.
+**
+** Just before the shared-btree is closed, the function passed as the
+** xFree argument when the memory allocation was made is invoked on the
+** blob of allocated memory. The xFree function should not call sqlite3_free()
+** on the memory, the btree layer does that.
+*/
+SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *p, int nBytes, void(*xFree)(void *)){
+  BtShared *pBt = p->pBt;
+  sqlite3BtreeEnter(p);
+  if( !pBt->pSchema && nBytes ){
+    pBt->pSchema = sqlite3DbMallocZero(0, nBytes);
+    pBt->xFreeSchema = xFree;
+  }
+  sqlite3BtreeLeave(p);
+  return pBt->pSchema;
+}
+
+/*
+** Return SQLITE_LOCKED_SHAREDCACHE if another user of the same shared
+** btree as the argument handle holds an exclusive lock on the
+** sqlite_schema table. Otherwise SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *p){
+  int rc;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  rc = querySharedCacheTableLock(p, SCHEMA_ROOT, READ_LOCK);
+  assert( rc==SQLITE_OK || rc==SQLITE_LOCKED_SHAREDCACHE );
+  sqlite3BtreeLeave(p);
+  return rc;
+}
+
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** Obtain a lock on the table whose root page is iTab.  The
+** lock is a write lock if isWritelock is true or a read lock
+** if it is false.
+*/
+SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *p, int iTab, u8 isWriteLock){
+  int rc = SQLITE_OK;
+  assert( p->inTrans!=TRANS_NONE );
+  if( p->sharable ){
+    u8 lockType = READ_LOCK + isWriteLock;
+    assert( READ_LOCK+1==WRITE_LOCK );
+    assert( isWriteLock==0 || isWriteLock==1 );
+
+    sqlite3BtreeEnter(p);
+    rc = querySharedCacheTableLock(p, iTab, lockType);
+    if( rc==SQLITE_OK ){
+      rc = setSharedCacheTableLock(p, iTab, lockType);
+    }
+    sqlite3BtreeLeave(p);
+  }
+  return rc;
+}
+#endif
+
+#ifndef SQLITE_OMIT_INCRBLOB
+/*
+** Argument pCsr must be a cursor opened for writing on an
+** INTKEY table currently pointing at a valid table entry.
+** This function modifies the data stored as part of that entry.
+**
+** Only the data content may only be modified, it is not possible to
+** change the length of the data stored. If this function is called with
+** parameters that attempt to write past the end of the existing data,
+** no modifications are made and SQLITE_CORRUPT is returned.
+*/
+SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void *z){
+  int rc;
+  assert( cursorOwnsBtShared(pCsr) );
+  assert( sqlite3_mutex_held(pCsr->pBtree->db->mutex) );
+  assert( pCsr->curFlags & BTCF_Incrblob );
+
+  rc = restoreCursorPosition(pCsr);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+  assert( pCsr->eState!=CURSOR_REQUIRESEEK );
+  if( pCsr->eState!=CURSOR_VALID ){
+    return SQLITE_ABORT;
+  }
+
+  /* Save the positions of all other cursors open on this table. This is
+  ** required in case any of them are holding references to an xFetch
+  ** version of the b-tree page modified by the accessPayload call below.
+  **
+  ** Note that pCsr must be open on a INTKEY table and saveCursorPosition()
+  ** and hence saveAllCursors() cannot fail on a BTREE_INTKEY table, hence
+  ** saveAllCursors can only return SQLITE_OK.
+  */
+  VVA_ONLY(rc =) saveAllCursors(pCsr->pBt, pCsr->pgnoRoot, pCsr);
+  assert( rc==SQLITE_OK );
+
+  /* Check some assumptions:
+  **   (a) the cursor is open for writing,
+  **   (b) there is a read/write transaction open,
+  **   (c) the connection holds a write-lock on the table (if required),
+  **   (d) there are no conflicting read-locks, and
+  **   (e) the cursor points at a valid row of an intKey table.
+  */
+  if( (pCsr->curFlags & BTCF_WriteFlag)==0 ){
+    return SQLITE_READONLY;
+  }
+  assert( (pCsr->pBt->btsFlags & BTS_READ_ONLY)==0
+              && pCsr->pBt->inTransaction==TRANS_WRITE );
+  assert( hasSharedCacheTableLock(pCsr->pBtree, pCsr->pgnoRoot, 0, 2) );
+  assert( !hasReadConflicts(pCsr->pBtree, pCsr->pgnoRoot) );
+  assert( pCsr->pPage->intKey );
+
+  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 1);
+}
+
+/*
+** Mark this cursor as an incremental blob cursor.
+*/
+SQLITE_PRIVATE void sqlite3BtreeIncrblobCursor(BtCursor *pCur){
+  pCur->curFlags |= BTCF_Incrblob;
+  pCur->pBtree->hasIncrblobCur = 1;
+}
+#endif
+
+/*
+** Set both the "read version" (single byte at byte offset 18) and
+** "write version" (single byte at byte offset 19) fields in the database
+** header to iVersion.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
+  BtShared *pBt = pBtree->pBt;
+  int rc;                         /* Return code */
+
+  assert( iVersion==1 || iVersion==2 );
+
+  /* If setting the version fields to 1, do not automatically open the
+  ** WAL connection, even if the version fields are currently set to 2.
+  */
+  pBt->btsFlags &= ~BTS_NO_WAL;
+  if( iVersion==1 ) pBt->btsFlags |= BTS_NO_WAL;
+
+  rc = sqlite3BtreeBeginTrans(pBtree, 0, 0);
+  if( rc==SQLITE_OK ){
+    u8 *aData = pBt->pPage1->aData;
+    if( aData[18]!=(u8)iVersion || aData[19]!=(u8)iVersion ){
+      rc = sqlite3BtreeBeginTrans(pBtree, 2, 0);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
+        if( rc==SQLITE_OK ){
+          aData[18] = (u8)iVersion;
+          aData[19] = (u8)iVersion;
+        }
+      }
+    }
+  }
+
+  pBt->btsFlags &= ~BTS_NO_WAL;
+  return rc;
+}
+
+/*
+** Return true if the cursor has a hint specified.  This routine is
+** only used from within assert() statements
+*/
+SQLITE_PRIVATE int sqlite3BtreeCursorHasHint(BtCursor *pCsr, unsigned int mask){
+  return (pCsr->hints & mask)!=0;
+}
+
+/*
+** Return true if the given Btree is read-only.
+*/
+SQLITE_PRIVATE int sqlite3BtreeIsReadonly(Btree *p){
+  return (p->pBt->btsFlags & BTS_READ_ONLY)!=0;
+}
+
+/*
+** Return the size of the header added to each page by this module.
+*/
+SQLITE_PRIVATE int sqlite3HeaderSizeBtree(void){ return ROUND8(sizeof(MemPage)); }
+
+/*
+** If no transaction is active and the database is not a temp-db, clear
+** the in-memory pager cache.
+*/
+SQLITE_PRIVATE void sqlite3BtreeClearCache(Btree *p){
+  BtShared *pBt = p->pBt;
+  if( pBt->inTransaction==TRANS_NONE ){
+    sqlite3PagerClearCache(pBt->pPager);
+  }
+}
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE)
+/*
+** Return true if the Btree passed as the only argument is sharable.
+*/
+SQLITE_PRIVATE int sqlite3BtreeSharable(Btree *p){
+  return p->sharable;
+}
+
+/*
+** Return the number of connections to the BtShared object accessed by
+** the Btree handle passed as the only argument. For private caches
+** this is always 1. For shared caches it may be 1 or greater.
+*/
+SQLITE_PRIVATE int sqlite3BtreeConnectionCount(Btree *p){
+  testcase( p->sharable );
+  return p->pBt->nRef;
+}
+#endif
+
+/************** End of btree.c ***********************************************/
+/************** Begin file backup.c ******************************************/
+/*
+** 2009 January 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the implementation of the sqlite3_backup_XXX()
+** API functions and the related features.
+*/
+/* #include "sqliteInt.h" */
+/* #include "btreeInt.h" */
+
+/*
+** Structure allocated for each backup operation.
+*/
+struct sqlite3_backup {
+  sqlite3* pDestDb;        /* Destination database handle */
+  Btree *pDest;            /* Destination b-tree file */
+  u32 iDestSchema;         /* Original schema cookie in destination */
+  int bDestLocked;         /* True once a write-transaction is open on pDest */
+
+  Pgno iNext;              /* Page number of the next source page to copy */
+  sqlite3* pSrcDb;         /* Source database handle */
+  Btree *pSrc;             /* Source b-tree file */
+
+  int rc;                  /* Backup process error code */
+
+  /* These two variables are set by every call to backup_step(). They are
+  ** read by calls to backup_remaining() and backup_pagecount().
+  */
+  Pgno nRemaining;         /* Number of pages left to copy */
+  Pgno nPagecount;         /* Total number of pages to copy */
+
+  int isAttached;          /* True once backup has been registered with pager */
+  sqlite3_backup *pNext;   /* Next backup associated with source pager */
+};
+
+/*
+** THREAD SAFETY NOTES:
+**
+**   Once it has been created using backup_init(), a single sqlite3_backup
+**   structure may be accessed via two groups of thread-safe entry points:
+**
+**     * Via the sqlite3_backup_XXX() API function backup_step() and
+**       backup_finish(). Both these functions obtain the source database
+**       handle mutex and the mutex associated with the source BtShared
+**       structure, in that order.
+**
+**     * Via the BackupUpdate() and BackupRestart() functions, which are
+**       invoked by the pager layer to report various state changes in
+**       the page cache associated with the source database. The mutex
+**       associated with the source database BtShared structure will always
+**       be held when either of these functions are invoked.
+**
+**   The other sqlite3_backup_XXX() API functions, backup_remaining() and
+**   backup_pagecount() are not thread-safe functions. If they are called
+**   while some other thread is calling backup_step() or backup_finish(),
+**   the values returned may be invalid. There is no way for a call to
+**   BackupUpdate() or BackupRestart() to interfere with backup_remaining()
+**   or backup_pagecount().
+**
+**   Depending on the SQLite configuration, the database handles and/or
+**   the Btree objects may have their own mutexes that require locking.
+**   Non-sharable Btrees (in-memory databases for example), do not have
+**   associated mutexes.
+*/
+
+/*
+** Return a pointer corresponding to database zDb (i.e. "main", "temp")
+** in connection handle pDb. If such a database cannot be found, return
+** a NULL pointer and write an error message to pErrorDb.
+**
+** If the "temp" database is requested, it may need to be opened by this
+** function. If an error occurs while doing so, return 0 and write an
+** error message to pErrorDb.
+*/
+static Btree *findBtree(sqlite3 *pErrorDb, sqlite3 *pDb, const char *zDb){
+  int i = sqlite3FindDbName(pDb, zDb);
+
+  if( i==1 ){
+    Parse sParse;
+    int rc = 0;
+    sqlite3ParseObjectInit(&sParse,pDb);
+    if( sqlite3OpenTempDatabase(&sParse) ){
+      sqlite3ErrorWithMsg(pErrorDb, sParse.rc, "%s", sParse.zErrMsg);
+      rc = SQLITE_ERROR;
+    }
+    sqlite3DbFree(pErrorDb, sParse.zErrMsg);
+    sqlite3ParseObjectReset(&sParse);
+    if( rc ){
+      return 0;
+    }
+  }
+
+  if( i<0 ){
+    sqlite3ErrorWithMsg(pErrorDb, SQLITE_ERROR, "unknown database %s", zDb);
+    return 0;
+  }
+
+  return pDb->aDb[i].pBt;
+}
+
+/*
+** Attempt to set the page size of the destination to match the page size
+** of the source.
+*/
+static int setDestPgsz(sqlite3_backup *p){
+  int rc;
+  rc = sqlite3BtreeSetPageSize(p->pDest,sqlite3BtreeGetPageSize(p->pSrc),0,0);
+  return rc;
+}
+
+/*
+** Check that there is no open read-transaction on the b-tree passed as the
+** second argument. If there is not, return SQLITE_OK. Otherwise, if there
+** is an open read-transaction, return SQLITE_ERROR and leave an error
+** message in database handle db.
+*/
+static int checkReadTransaction(sqlite3 *db, Btree *p){
+  if( sqlite3BtreeTxnState(p)!=SQLITE_TXN_NONE ){
+    sqlite3ErrorWithMsg(db, SQLITE_ERROR, "destination database is in use");
+    return SQLITE_ERROR;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Create an sqlite3_backup process to copy the contents of zSrcDb from
+** connection handle pSrcDb to zDestDb in pDestDb. If successful, return
+** a pointer to the new sqlite3_backup object.
+**
+** If an error occurs, NULL is returned and an error code and error message
+** stored in database handle pDestDb.
+*/
+SQLITE_API sqlite3_backup *sqlite3_backup_init(
+  sqlite3* pDestDb,                     /* Database to write to */
+  const char *zDestDb,                  /* Name of database within pDestDb */
+  sqlite3* pSrcDb,                      /* Database connection to read from */
+  const char *zSrcDb                    /* Name of database within pSrcDb */
+){
+  sqlite3_backup *p;                    /* Value to return */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(pSrcDb)||!sqlite3SafetyCheckOk(pDestDb) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+
+  /* Lock the source database handle. The destination database
+  ** handle is not locked in this routine, but it is locked in
+  ** sqlite3_backup_step(). The user is required to ensure that no
+  ** other thread accesses the destination handle for the duration
+  ** of the backup operation.  Any attempt to use the destination
+  ** database connection while a backup is in progress may cause
+  ** a malfunction or a deadlock.
+  */
+  sqlite3_mutex_enter(pSrcDb->mutex);
+  sqlite3_mutex_enter(pDestDb->mutex);
+
+  if( pSrcDb==pDestDb ){
+    sqlite3ErrorWithMsg(
+        pDestDb, SQLITE_ERROR, "source and destination must be distinct"
+    );
+    p = 0;
+  }else {
+    /* Allocate space for a new sqlite3_backup object...
+    ** EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a
+    ** call to sqlite3_backup_init() and is destroyed by a call to
+    ** sqlite3_backup_finish(). */
+    p = (sqlite3_backup *)sqlite3MallocZero(sizeof(sqlite3_backup));
+    if( !p ){
+      sqlite3Error(pDestDb, SQLITE_NOMEM_BKPT);
+    }
+  }
+
+  /* If the allocation succeeded, populate the new object. */
+  if( p ){
+    p->pSrc = findBtree(pDestDb, pSrcDb, zSrcDb);
+    p->pDest = findBtree(pDestDb, pDestDb, zDestDb);
+    p->pDestDb = pDestDb;
+    p->pSrcDb = pSrcDb;
+    p->iNext = 1;
+    p->isAttached = 0;
+
+    if( 0==p->pSrc || 0==p->pDest
+     || checkReadTransaction(pDestDb, p->pDest)!=SQLITE_OK
+     ){
+      /* One (or both) of the named databases did not exist or an OOM
+      ** error was hit. Or there is a transaction open on the destination
+      ** database. The error has already been written into the pDestDb
+      ** handle. All that is left to do here is free the sqlite3_backup
+      ** structure.  */
+      sqlite3_free(p);
+      p = 0;
+    }
+  }
+  if( p ){
+    p->pSrc->nBackup++;
+  }
+
+  sqlite3_mutex_leave(pDestDb->mutex);
+  sqlite3_mutex_leave(pSrcDb->mutex);
+  return p;
+}
+
+/*
+** Argument rc is an SQLite error code. Return true if this error is
+** considered fatal if encountered during a backup operation. All errors
+** are considered fatal except for SQLITE_BUSY and SQLITE_LOCKED.
+*/
+static int isFatalError(int rc){
+  return (rc!=SQLITE_OK && rc!=SQLITE_BUSY && ALWAYS(rc!=SQLITE_LOCKED));
+}
+
+/*
+** Parameter zSrcData points to a buffer containing the data for
+** page iSrcPg from the source database. Copy this data into the
+** destination database.
+*/
+static int backupOnePage(
+  sqlite3_backup *p,              /* Backup handle */
+  Pgno iSrcPg,                    /* Source database page to backup */
+  const u8 *zSrcData,             /* Source database page data */
+  int bUpdate                     /* True for an update, false otherwise */
+){
+  Pager * const pDestPager = sqlite3BtreePager(p->pDest);
+  const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc);
+  int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest);
+  const int nCopy = MIN(nSrcPgsz, nDestPgsz);
+  const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz;
+  int rc = SQLITE_OK;
+  i64 iOff;
+
+  assert( sqlite3BtreeGetReserveNoMutex(p->pSrc)>=0 );
+  assert( p->bDestLocked );
+  assert( !isFatalError(p->rc) );
+  assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) );
+  assert( zSrcData );
+  assert( nSrcPgsz==nDestPgsz || sqlite3PagerIsMemdb(pDestPager)==0 );
+
+  /* This loop runs once for each destination page spanned by the source
+  ** page. For each iteration, variable iOff is set to the byte offset
+  ** of the destination page.
+  */
+  for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){
+    DbPage *pDestPg = 0;
+    Pgno iDest = (Pgno)(iOff/nDestPgsz)+1;
+    if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue;
+    if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg, 0))
+     && SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg))
+    ){
+      const u8 *zIn = &zSrcData[iOff%nSrcPgsz];
+      u8 *zDestData = sqlite3PagerGetData(pDestPg);
+      u8 *zOut = &zDestData[iOff%nDestPgsz];
+
+      /* Copy the data from the source page into the destination page.
+      ** Then clear the Btree layer MemPage.isInit flag. Both this module
+      ** and the pager code use this trick (clearing the first byte
+      ** of the page 'extra' space to invalidate the Btree layers
+      ** cached parse of the page). MemPage.isInit is marked
+      ** "MUST BE FIRST" for this purpose.
+      */
+      memcpy(zOut, zIn, nCopy);
+      ((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0;
+      if( iOff==0 && bUpdate==0 ){
+        sqlite3Put4byte(&zOut[28], sqlite3BtreeLastPage(p->pSrc));
+      }
+    }
+    sqlite3PagerUnref(pDestPg);
+  }
+
+  return rc;
+}
+
+/*
+** If pFile is currently larger than iSize bytes, then truncate it to
+** exactly iSize bytes. If pFile is not larger than iSize bytes, then
+** this function is a no-op.
+**
+** Return SQLITE_OK if everything is successful, or an SQLite error
+** code if an error occurs.
+*/
+static int backupTruncateFile(sqlite3_file *pFile, i64 iSize){
+  i64 iCurrent;
+  int rc = sqlite3OsFileSize(pFile, &iCurrent);
+  if( rc==SQLITE_OK && iCurrent>iSize ){
+    rc = sqlite3OsTruncate(pFile, iSize);
+  }
+  return rc;
+}
+
+/*
+** Register this backup object with the associated source pager for
+** callbacks when pages are changed or the cache invalidated.
+*/
+static void attachBackupObject(sqlite3_backup *p){
+  sqlite3_backup **pp;
+  assert( sqlite3BtreeHoldsMutex(p->pSrc) );
+  pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
+  p->pNext = *pp;
+  *pp = p;
+  p->isAttached = 1;
+}
+
+/*
+** Copy nPage pages from the source b-tree to the destination.
+*/
+SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage){
+  int rc;
+  int destMode;       /* Destination journal mode */
+  int pgszSrc = 0;    /* Source page size */
+  int pgszDest = 0;   /* Destination page size */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(p->pSrcDb->mutex);
+  sqlite3BtreeEnter(p->pSrc);
+  if( p->pDestDb ){
+    sqlite3_mutex_enter(p->pDestDb->mutex);
+  }
+
+  rc = p->rc;
+  if( !isFatalError(rc) ){
+    Pager * const pSrcPager = sqlite3BtreePager(p->pSrc);     /* Source pager */
+    Pager * const pDestPager = sqlite3BtreePager(p->pDest);   /* Dest pager */
+    int ii;                            /* Iterator variable */
+    int nSrcPage = -1;                 /* Size of source db in pages */
+    int bCloseTrans = 0;               /* True if src db requires unlocking */
+
+    /* If the source pager is currently in a write-transaction, return
+    ** SQLITE_BUSY immediately.
+    */
+    if( p->pDestDb && p->pSrc->pBt->inTransaction==TRANS_WRITE ){
+      rc = SQLITE_BUSY;
+    }else{
+      rc = SQLITE_OK;
+    }
+
+    /* If there is no open read-transaction on the source database, open
+    ** one now. If a transaction is opened here, then it will be closed
+    ** before this function exits.
+    */
+    if( rc==SQLITE_OK && SQLITE_TXN_NONE==sqlite3BtreeTxnState(p->pSrc) ){
+      rc = sqlite3BtreeBeginTrans(p->pSrc, 0, 0);
+      bCloseTrans = 1;
+    }
+
+    /* If the destination database has not yet been locked (i.e. if this
+    ** is the first call to backup_step() for the current backup operation),
+    ** try to set its page size to the same as the source database. This
+    ** is especially important on ZipVFS systems, as in that case it is
+    ** not possible to create a database file that uses one page size by
+    ** writing to it with another.  */
+    if( p->bDestLocked==0 && rc==SQLITE_OK && setDestPgsz(p)==SQLITE_NOMEM ){
+      rc = SQLITE_NOMEM;
+    }
+
+    /* Lock the destination database, if it is not locked already. */
+    if( SQLITE_OK==rc && p->bDestLocked==0
+     && SQLITE_OK==(rc = sqlite3BtreeBeginTrans(p->pDest, 2,
+                                                (int*)&p->iDestSchema))
+    ){
+      p->bDestLocked = 1;
+    }
+
+    /* Do not allow backup if the destination database is in WAL mode
+    ** and the page sizes are different between source and destination */
+    pgszSrc = sqlite3BtreeGetPageSize(p->pSrc);
+    pgszDest = sqlite3BtreeGetPageSize(p->pDest);
+    destMode = sqlite3PagerGetJournalMode(sqlite3BtreePager(p->pDest));
+    if( SQLITE_OK==rc
+     && (destMode==PAGER_JOURNALMODE_WAL || sqlite3PagerIsMemdb(pDestPager))
+     && pgszSrc!=pgszDest
+    ){
+      rc = SQLITE_READONLY;
+    }
+
+    /* Now that there is a read-lock on the source database, query the
+    ** source pager for the number of pages in the database.
+    */
+    nSrcPage = (int)sqlite3BtreeLastPage(p->pSrc);
+    assert( nSrcPage>=0 );
+    for(ii=0; (nPage<0 || ii<nPage) && p->iNext<=(Pgno)nSrcPage && !rc; ii++){
+      const Pgno iSrcPg = p->iNext;                 /* Source page number */
+      if( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ){
+        DbPage *pSrcPg;                             /* Source page object */
+        rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg,PAGER_GET_READONLY);
+        if( rc==SQLITE_OK ){
+          rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg), 0);
+          sqlite3PagerUnref(pSrcPg);
+        }
+      }
+      p->iNext++;
+    }
+    if( rc==SQLITE_OK ){
+      p->nPagecount = nSrcPage;
+      p->nRemaining = nSrcPage+1-p->iNext;
+      if( p->iNext>(Pgno)nSrcPage ){
+        rc = SQLITE_DONE;
+      }else if( !p->isAttached ){
+        attachBackupObject(p);
+      }
+    }
+
+    /* Update the schema version field in the destination database. This
+    ** is to make sure that the schema-version really does change in
+    ** the case where the source and destination databases have the
+    ** same schema version.
+    */
+    if( rc==SQLITE_DONE ){
+      if( nSrcPage==0 ){
+        rc = sqlite3BtreeNewDb(p->pDest);
+        nSrcPage = 1;
+      }
+      if( rc==SQLITE_OK || rc==SQLITE_DONE ){
+        rc = sqlite3BtreeUpdateMeta(p->pDest,1,p->iDestSchema+1);
+      }
+      if( rc==SQLITE_OK ){
+        if( p->pDestDb ){
+          sqlite3ResetAllSchemasOfConnection(p->pDestDb);
+        }
+        if( destMode==PAGER_JOURNALMODE_WAL ){
+          rc = sqlite3BtreeSetVersion(p->pDest, 2);
+        }
+      }
+      if( rc==SQLITE_OK ){
+        int nDestTruncate;
+        /* Set nDestTruncate to the final number of pages in the destination
+        ** database. The complication here is that the destination page
+        ** size may be different to the source page size.
+        **
+        ** If the source page size is smaller than the destination page size,
+        ** round up. In this case the call to sqlite3OsTruncate() below will
+        ** fix the size of the file. However it is important to call
+        ** sqlite3PagerTruncateImage() here so that any pages in the
+        ** destination file that lie beyond the nDestTruncate page mark are
+        ** journalled by PagerCommitPhaseOne() before they are destroyed
+        ** by the file truncation.
+        */
+        assert( pgszSrc==sqlite3BtreeGetPageSize(p->pSrc) );
+        assert( pgszDest==sqlite3BtreeGetPageSize(p->pDest) );
+        if( pgszSrc<pgszDest ){
+          int ratio = pgszDest/pgszSrc;
+          nDestTruncate = (nSrcPage+ratio-1)/ratio;
+          if( nDestTruncate==(int)PENDING_BYTE_PAGE(p->pDest->pBt) ){
+            nDestTruncate--;
+          }
+        }else{
+          nDestTruncate = nSrcPage * (pgszSrc/pgszDest);
+        }
+        assert( nDestTruncate>0 );
+
+        if( pgszSrc<pgszDest ){
+          /* If the source page-size is smaller than the destination page-size,
+          ** two extra things may need to happen:
+          **
+          **   * The destination may need to be truncated, and
+          **
+          **   * Data stored on the pages immediately following the
+          **     pending-byte page in the source database may need to be
+          **     copied into the destination database.
+          */
+          const i64 iSize = (i64)pgszSrc * (i64)nSrcPage;
+          sqlite3_file * const pFile = sqlite3PagerFile(pDestPager);
+          Pgno iPg;
+          int nDstPage;
+          i64 iOff;
+          i64 iEnd;
+
+          assert( pFile );
+          assert( nDestTruncate==0
+              || (i64)nDestTruncate*(i64)pgszDest >= iSize || (
+                nDestTruncate==(int)(PENDING_BYTE_PAGE(p->pDest->pBt)-1)
+             && iSize>=PENDING_BYTE && iSize<=PENDING_BYTE+pgszDest
+          ));
+
+          /* This block ensures that all data required to recreate the original
+          ** database has been stored in the journal for pDestPager and the
+          ** journal synced to disk. So at this point we may safely modify
+          ** the database file in any way, knowing that if a power failure
+          ** occurs, the original database will be reconstructed from the
+          ** journal file.  */
+          sqlite3PagerPagecount(pDestPager, &nDstPage);
+          for(iPg=nDestTruncate; rc==SQLITE_OK && iPg<=(Pgno)nDstPage; iPg++){
+            if( iPg!=PENDING_BYTE_PAGE(p->pDest->pBt) ){
+              DbPage *pPg;
+              rc = sqlite3PagerGet(pDestPager, iPg, &pPg, 0);
+              if( rc==SQLITE_OK ){
+                rc = sqlite3PagerWrite(pPg);
+                sqlite3PagerUnref(pPg);
+              }
+            }
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 1);
+          }
+
+          /* Write the extra pages and truncate the database file as required */
+          iEnd = MIN(PENDING_BYTE + pgszDest, iSize);
+          for(
+            iOff=PENDING_BYTE+pgszSrc;
+            rc==SQLITE_OK && iOff<iEnd;
+            iOff+=pgszSrc
+          ){
+            PgHdr *pSrcPg = 0;
+            const Pgno iSrcPg = (Pgno)((iOff/pgszSrc)+1);
+            rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg, 0);
+            if( rc==SQLITE_OK ){
+              u8 *zData = sqlite3PagerGetData(pSrcPg);
+              rc = sqlite3OsWrite(pFile, zData, pgszSrc, iOff);
+            }
+            sqlite3PagerUnref(pSrcPg);
+          }
+          if( rc==SQLITE_OK ){
+            rc = backupTruncateFile(pFile, iSize);
+          }
+
+          /* Sync the database file to disk. */
+          if( rc==SQLITE_OK ){
+            rc = sqlite3PagerSync(pDestPager, 0);
+          }
+        }else{
+          sqlite3PagerTruncateImage(pDestPager, nDestTruncate);
+          rc = sqlite3PagerCommitPhaseOne(pDestPager, 0, 0);
+        }
+
+        /* Finish committing the transaction to the destination database. */
+        if( SQLITE_OK==rc
+         && SQLITE_OK==(rc = sqlite3BtreeCommitPhaseTwo(p->pDest, 0))
+        ){
+          rc = SQLITE_DONE;
+        }
+      }
+    }
+
+    /* If bCloseTrans is true, then this function opened a read transaction
+    ** on the source database. Close the read transaction here. There is
+    ** no need to check the return values of the btree methods here, as
+    ** "committing" a read-only transaction cannot fail.
+    */
+    if( bCloseTrans ){
+      TESTONLY( int rc2 );
+      TESTONLY( rc2  = ) sqlite3BtreeCommitPhaseOne(p->pSrc, 0);
+      TESTONLY( rc2 |= ) sqlite3BtreeCommitPhaseTwo(p->pSrc, 0);
+      assert( rc2==SQLITE_OK );
+    }
+
+    if( rc==SQLITE_IOERR_NOMEM ){
+      rc = SQLITE_NOMEM_BKPT;
+    }
+    p->rc = rc;
+  }
+  if( p->pDestDb ){
+    sqlite3_mutex_leave(p->pDestDb->mutex);
+  }
+  sqlite3BtreeLeave(p->pSrc);
+  sqlite3_mutex_leave(p->pSrcDb->mutex);
+  return rc;
+}
+
+/*
+** Release all resources associated with an sqlite3_backup* handle.
+*/
+SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p){
+  sqlite3_backup **pp;                 /* Ptr to head of pagers backup list */
+  sqlite3 *pSrcDb;                     /* Source database connection */
+  int rc;                              /* Value to return */
+
+  /* Enter the mutexes */
+  if( p==0 ) return SQLITE_OK;
+  pSrcDb = p->pSrcDb;
+  sqlite3_mutex_enter(pSrcDb->mutex);
+  sqlite3BtreeEnter(p->pSrc);
+  if( p->pDestDb ){
+    sqlite3_mutex_enter(p->pDestDb->mutex);
+  }
+
+  /* Detach this backup from the source pager. */
+  if( p->pDestDb ){
+    p->pSrc->nBackup--;
+  }
+  if( p->isAttached ){
+    pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
+    assert( pp!=0 );
+    while( *pp!=p ){
+      pp = &(*pp)->pNext;
+      assert( pp!=0 );
+    }
+    *pp = p->pNext;
+  }
+
+  /* If a transaction is still open on the Btree, roll it back. */
+  sqlite3BtreeRollback(p->pDest, SQLITE_OK, 0);
+
+  /* Set the error code of the destination database handle. */
+  rc = (p->rc==SQLITE_DONE) ? SQLITE_OK : p->rc;
+  if( p->pDestDb ){
+    sqlite3Error(p->pDestDb, rc);
+
+    /* Exit the mutexes and free the backup context structure. */
+    sqlite3LeaveMutexAndCloseZombie(p->pDestDb);
+  }
+  sqlite3BtreeLeave(p->pSrc);
+  if( p->pDestDb ){
+    /* EVIDENCE-OF: R-64852-21591 The sqlite3_backup object is created by a
+    ** call to sqlite3_backup_init() and is destroyed by a call to
+    ** sqlite3_backup_finish(). */
+    sqlite3_free(p);
+  }
+  sqlite3LeaveMutexAndCloseZombie(pSrcDb);
+  return rc;
+}
+
+/*
+** Return the number of pages still to be backed up as of the most recent
+** call to sqlite3_backup_step().
+*/
+SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return p->nRemaining;
+}
+
+/*
+** Return the total number of pages in the source database as of the most
+** recent call to sqlite3_backup_step().
+*/
+SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return p->nPagecount;
+}
+
+/*
+** This function is called after the contents of page iPage of the
+** source database have been modified. If page iPage has already been
+** copied into the destination database, then the data written to the
+** destination is now invalidated. The destination copy of iPage needs
+** to be updated with the new data before the backup operation is
+** complete.
+**
+** It is assumed that the mutex associated with the BtShared object
+** corresponding to the source database is held when this function is
+** called.
+*/
+static SQLITE_NOINLINE void backupUpdate(
+  sqlite3_backup *p,
+  Pgno iPage,
+  const u8 *aData
+){
+  assert( p!=0 );
+  do{
+    assert( sqlite3_mutex_held(p->pSrc->pBt->mutex) );
+    if( !isFatalError(p->rc) && iPage<p->iNext ){
+      /* The backup process p has already copied page iPage. But now it
+      ** has been modified by a transaction on the source pager. Copy
+      ** the new data into the backup.
+      */
+      int rc;
+      assert( p->pDestDb );
+      sqlite3_mutex_enter(p->pDestDb->mutex);
+      rc = backupOnePage(p, iPage, aData, 1);
+      sqlite3_mutex_leave(p->pDestDb->mutex);
+      assert( rc!=SQLITE_BUSY && rc!=SQLITE_LOCKED );
+      if( rc!=SQLITE_OK ){
+        p->rc = rc;
+      }
+    }
+  }while( (p = p->pNext)!=0 );
+}
+SQLITE_PRIVATE void sqlite3BackupUpdate(sqlite3_backup *pBackup, Pgno iPage, const u8 *aData){
+  if( pBackup ) backupUpdate(pBackup, iPage, aData);
+}
+
+/*
+** Restart the backup process. This is called when the pager layer
+** detects that the database has been modified by an external database
+** connection. In this case there is no way of knowing which of the
+** pages that have been copied into the destination database are still
+** valid and which are not, so the entire process needs to be restarted.
+**
+** It is assumed that the mutex associated with the BtShared object
+** corresponding to the source database is held when this function is
+** called.
+*/
+SQLITE_PRIVATE void sqlite3BackupRestart(sqlite3_backup *pBackup){
+  sqlite3_backup *p;                   /* Iterator variable */
+  for(p=pBackup; p; p=p->pNext){
+    assert( sqlite3_mutex_held(p->pSrc->pBt->mutex) );
+    p->iNext = 1;
+  }
+}
+
+#ifndef SQLITE_OMIT_VACUUM
+/*
+** Copy the complete content of pBtFrom into pBtTo.  A transaction
+** must be active for both files.
+**
+** The size of file pTo may be reduced by this operation. If anything
+** goes wrong, the transaction on pTo is rolled back. If successful, the
+** transaction is committed before returning.
+*/
+SQLITE_PRIVATE int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){
+  int rc;
+  sqlite3_file *pFd;              /* File descriptor for database pTo */
+  sqlite3_backup b;
+  sqlite3BtreeEnter(pTo);
+  sqlite3BtreeEnter(pFrom);
+
+  assert( sqlite3BtreeTxnState(pTo)==SQLITE_TXN_WRITE );
+  pFd = sqlite3PagerFile(sqlite3BtreePager(pTo));
+  if( pFd->pMethods ){
+    i64 nByte = sqlite3BtreeGetPageSize(pFrom)*(i64)sqlite3BtreeLastPage(pFrom);
+    rc = sqlite3OsFileControl(pFd, SQLITE_FCNTL_OVERWRITE, &nByte);
+    if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+    if( rc ) goto copy_finished;
+  }
+
+  /* Set up an sqlite3_backup object. sqlite3_backup.pDestDb must be set
+  ** to 0. This is used by the implementations of sqlite3_backup_step()
+  ** and sqlite3_backup_finish() to detect that they are being called
+  ** from this function, not directly by the user.
+  */
+  memset(&b, 0, sizeof(b));
+  b.pSrcDb = pFrom->db;
+  b.pSrc = pFrom;
+  b.pDest = pTo;
+  b.iNext = 1;
+
+  /* 0x7FFFFFFF is the hard limit for the number of pages in a database
+  ** file. By passing this as the number of pages to copy to
+  ** sqlite3_backup_step(), we can guarantee that the copy finishes
+  ** within a single call (unless an error occurs). The assert() statement
+  ** checks this assumption - (p->rc) should be set to either SQLITE_DONE
+  ** or an error code.  */
+  sqlite3_backup_step(&b, 0x7FFFFFFF);
+  assert( b.rc!=SQLITE_OK );
+
+  rc = sqlite3_backup_finish(&b);
+  if( rc==SQLITE_OK ){
+    pTo->pBt->btsFlags &= ~BTS_PAGESIZE_FIXED;
+  }else{
+    sqlite3PagerClearCache(sqlite3BtreePager(b.pDest));
+  }
+
+  assert( sqlite3BtreeTxnState(pTo)!=SQLITE_TXN_WRITE );
+copy_finished:
+  sqlite3BtreeLeave(pFrom);
+  sqlite3BtreeLeave(pTo);
+  return rc;
+}
+#endif /* SQLITE_OMIT_VACUUM */
+
+/************** End of backup.c **********************************************/
+/************** Begin file vdbemem.c *****************************************/
+/*
+** 2004 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code use to manipulate "Mem" structure.  A "Mem"
+** stores a single value in the VDBE.  Mem is an opaque structure visible
+** only within the VDBE.  Interface routines refer to a Mem using the
+** name sqlite_value
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+/* True if X is a power of two.  0 is considered a power of two here.
+** In other words, return true if X has at most one bit set.
+*/
+#define ISPOWEROF2(X)  (((X)&((X)-1))==0)
+
+#ifdef SQLITE_DEBUG
+/*
+** Check invariants on a Mem object.
+**
+** This routine is intended for use inside of assert() statements, like
+** this:    assert( sqlite3VdbeCheckMemInvariants(pMem) );
+*/
+SQLITE_PRIVATE int sqlite3VdbeCheckMemInvariants(Mem *p){
+  /* If MEM_Dyn is set then Mem.xDel!=0.
+  ** Mem.xDel might not be initialized if MEM_Dyn is clear.
+  */
+  assert( (p->flags & MEM_Dyn)==0 || p->xDel!=0 );
+
+  /* MEM_Dyn may only be set if Mem.szMalloc==0.  In this way we
+  ** ensure that if Mem.szMalloc>0 then it is safe to do
+  ** Mem.z = Mem.zMalloc without having to check Mem.flags&MEM_Dyn.
+  ** That saves a few cycles in inner loops. */
+  assert( (p->flags & MEM_Dyn)==0 || p->szMalloc==0 );
+
+  /* Cannot have more than one of MEM_Int, MEM_Real, or MEM_IntReal */
+  assert( ISPOWEROF2(p->flags & (MEM_Int|MEM_Real|MEM_IntReal)) );
+
+  if( p->flags & MEM_Null ){
+    /* Cannot be both MEM_Null and some other type */
+    assert( (p->flags & (MEM_Int|MEM_Real|MEM_Str|MEM_Blob|MEM_Agg))==0 );
+
+    /* If MEM_Null is set, then either the value is a pure NULL (the usual
+    ** case) or it is a pointer set using sqlite3_bind_pointer() or
+    ** sqlite3_result_pointer().  If a pointer, then MEM_Term must also be
+    ** set.
+    */
+    if( (p->flags & (MEM_Term|MEM_Subtype))==(MEM_Term|MEM_Subtype) ){
+      /* This is a pointer type.  There may be a flag to indicate what to
+      ** do with the pointer. */
+      assert( ((p->flags&MEM_Dyn)!=0 ? 1 : 0) +
+              ((p->flags&MEM_Ephem)!=0 ? 1 : 0) +
+              ((p->flags&MEM_Static)!=0 ? 1 : 0) <= 1 );
+
+      /* No other bits set */
+      assert( (p->flags & ~(MEM_Null|MEM_Term|MEM_Subtype|MEM_FromBind
+                           |MEM_Dyn|MEM_Ephem|MEM_Static))==0 );
+    }else{
+      /* A pure NULL might have other flags, such as MEM_Static, MEM_Dyn,
+      ** MEM_Ephem, MEM_Cleared, or MEM_Subtype */
+    }
+  }else{
+    /* The MEM_Cleared bit is only allowed on NULLs */
+    assert( (p->flags & MEM_Cleared)==0 );
+  }
+
+  /* The szMalloc field holds the correct memory allocation size */
+  assert( p->szMalloc==0
+       || (p->flags==MEM_Undefined
+           && p->szMalloc<=sqlite3DbMallocSize(p->db,p->zMalloc))
+       || p->szMalloc==sqlite3DbMallocSize(p->db,p->zMalloc));
+
+  /* If p holds a string or blob, the Mem.z must point to exactly
+  ** one of the following:
+  **
+  **   (1) Memory in Mem.zMalloc and managed by the Mem object
+  **   (2) Memory to be freed using Mem.xDel
+  **   (3) An ephemeral string or blob
+  **   (4) A static string or blob
+  */
+  if( (p->flags & (MEM_Str|MEM_Blob)) && p->n>0 ){
+    assert(
+      ((p->szMalloc>0 && p->z==p->zMalloc)? 1 : 0) +
+      ((p->flags&MEM_Dyn)!=0 ? 1 : 0) +
+      ((p->flags&MEM_Ephem)!=0 ? 1 : 0) +
+      ((p->flags&MEM_Static)!=0 ? 1 : 0) == 1
+    );
+  }
+  return 1;
+}
+#endif
+
+/*
+** Render a Mem object which is one of MEM_Int, MEM_Real, or MEM_IntReal
+** into a buffer.
+*/
+static void vdbeMemRenderNum(int sz, char *zBuf, Mem *p){
+  StrAccum acc;
+  assert( p->flags & (MEM_Int|MEM_Real|MEM_IntReal) );
+  assert( sz>22 );
+  if( p->flags & MEM_Int ){
+#if GCC_VERSION>=7000000
+    /* Work-around for GCC bug
+    ** https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96270 */
+    i64 x;
+    assert( (p->flags&MEM_Int)*2==sizeof(x) );
+    memcpy(&x, (char*)&p->u, (p->flags&MEM_Int)*2);
+    p->n = sqlite3Int64ToText(x, zBuf);
+#else
+    p->n = sqlite3Int64ToText(p->u.i, zBuf);
+#endif
+  }else{
+    sqlite3StrAccumInit(&acc, 0, zBuf, sz, 0);
+    sqlite3_str_appendf(&acc, "%!.15g",
+         (p->flags & MEM_IntReal)!=0 ? (double)p->u.i : p->u.r);
+    assert( acc.zText==zBuf && acc.mxAlloc<=0 );
+    zBuf[acc.nChar] = 0; /* Fast version of sqlite3StrAccumFinish(&acc) */
+    p->n = acc.nChar;
+  }
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Validity checks on pMem.  pMem holds a string.
+**
+** (1) Check that string value of pMem agrees with its integer or real value.
+** (2) Check that the string is correctly zero terminated
+**
+** A single int or real value always converts to the same strings.  But
+** many different strings can be converted into the same int or real.
+** If a table contains a numeric value and an index is based on the
+** corresponding string value, then it is important that the string be
+** derived from the numeric value, not the other way around, to ensure
+** that the index and table are consistent.  See ticket
+** https://www.sqlite.org/src/info/343634942dd54ab (2018-01-31) for
+** an example.
+**
+** This routine looks at pMem to verify that if it has both a numeric
+** representation and a string representation then the string rep has
+** been derived from the numeric and not the other way around.  It returns
+** true if everything is ok and false if there is a problem.
+**
+** This routine is for use inside of assert() statements only.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemValidStrRep(Mem *p){
+  Mem tmp;
+  char zBuf[100];
+  char *z;
+  int i, j, incr;
+  if( (p->flags & MEM_Str)==0 ) return 1;
+  if( p->db && p->db->mallocFailed ) return 1;
+  if( p->flags & MEM_Term ){
+    /* Insure that the string is properly zero-terminated.  Pay particular
+    ** attention to the case where p->n is odd */
+    if( p->szMalloc>0 && p->z==p->zMalloc ){
+      assert( p->enc==SQLITE_UTF8 || p->szMalloc >= ((p->n+1)&~1)+2 );
+      assert( p->enc!=SQLITE_UTF8 || p->szMalloc >= p->n+1 );
+    }
+    assert( p->z[p->n]==0 );
+    assert( p->enc==SQLITE_UTF8 || p->z[(p->n+1)&~1]==0 );
+    assert( p->enc==SQLITE_UTF8 || p->z[((p->n+1)&~1)+1]==0 );
+  }
+  if( (p->flags & (MEM_Int|MEM_Real|MEM_IntReal))==0 ) return 1;
+  memcpy(&tmp, p, sizeof(tmp));
+  vdbeMemRenderNum(sizeof(zBuf), zBuf, &tmp);
+  z = p->z;
+  i = j = 0;
+  incr = 1;
+  if( p->enc!=SQLITE_UTF8 ){
+    incr = 2;
+    if( p->enc==SQLITE_UTF16BE ) z++;
+  }
+  while( zBuf[j] ){
+    if( zBuf[j++]!=z[i] ) return 0;
+    i += incr;
+  }
+  return 1;
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** If pMem is an object with a valid string representation, this routine
+** ensures the internal encoding for the string representation is
+** 'desiredEnc', one of SQLITE_UTF8, SQLITE_UTF16LE or SQLITE_UTF16BE.
+**
+** If pMem is not a string object, or the encoding of the string
+** representation is already stored using the requested encoding, then this
+** routine is a no-op.
+**
+** SQLITE_OK is returned if the conversion is successful (or not required).
+** SQLITE_NOMEM may be returned if a malloc() fails during conversion
+** between formats.
+*/
+SQLITE_PRIVATE int sqlite3VdbeChangeEncoding(Mem *pMem, int desiredEnc){
+#ifndef SQLITE_OMIT_UTF16
+  int rc;
+#endif
+  assert( pMem!=0 );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( desiredEnc==SQLITE_UTF8 || desiredEnc==SQLITE_UTF16LE
+           || desiredEnc==SQLITE_UTF16BE );
+  if( !(pMem->flags&MEM_Str) ){
+    pMem->enc = desiredEnc;
+    return SQLITE_OK;
+  }
+  if( pMem->enc==desiredEnc ){
+    return SQLITE_OK;
+  }
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+#ifdef SQLITE_OMIT_UTF16
+  return SQLITE_ERROR;
+#else
+
+  /* MemTranslate() may return SQLITE_OK or SQLITE_NOMEM. If NOMEM is returned,
+  ** then the encoding of the value may not have changed.
+  */
+  rc = sqlite3VdbeMemTranslate(pMem, (u8)desiredEnc);
+  assert(rc==SQLITE_OK    || rc==SQLITE_NOMEM);
+  assert(rc==SQLITE_OK    || pMem->enc!=desiredEnc);
+  assert(rc==SQLITE_NOMEM || pMem->enc==desiredEnc);
+  return rc;
+#endif
+}
+
+/*
+** Make sure pMem->z points to a writable allocation of at least n bytes.
+**
+** If the bPreserve argument is true, then copy of the content of
+** pMem->z into the new allocation.  pMem must be either a string or
+** blob if bPreserve is true.  If bPreserve is false, any prior content
+** in pMem->z is discarded.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3VdbeMemGrow(Mem *pMem, int n, int bPreserve){
+  assert( sqlite3VdbeCheckMemInvariants(pMem) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  testcase( pMem->db==0 );
+
+  /* If the bPreserve flag is set to true, then the memory cell must already
+  ** contain a valid string or blob value.  */
+  assert( bPreserve==0 || pMem->flags&(MEM_Blob|MEM_Str) );
+  testcase( bPreserve && pMem->z==0 );
+
+  assert( pMem->szMalloc==0
+       || (pMem->flags==MEM_Undefined
+           && pMem->szMalloc<=sqlite3DbMallocSize(pMem->db,pMem->zMalloc))
+       || pMem->szMalloc==sqlite3DbMallocSize(pMem->db,pMem->zMalloc));
+  if( pMem->szMalloc>0 && bPreserve && pMem->z==pMem->zMalloc ){
+    if( pMem->db ){
+      pMem->z = pMem->zMalloc = sqlite3DbReallocOrFree(pMem->db, pMem->z, n);
+    }else{
+      pMem->zMalloc = sqlite3Realloc(pMem->z, n);
+      if( pMem->zMalloc==0 ) sqlite3_free(pMem->z);
+      pMem->z = pMem->zMalloc;
+    }
+    bPreserve = 0;
+  }else{
+    if( pMem->szMalloc>0 ) sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
+    pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, n);
+  }
+  if( pMem->zMalloc==0 ){
+    sqlite3VdbeMemSetNull(pMem);
+    pMem->z = 0;
+    pMem->szMalloc = 0;
+    return SQLITE_NOMEM_BKPT;
+  }else{
+    pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->zMalloc);
+  }
+
+  if( bPreserve && pMem->z ){
+    assert( pMem->z!=pMem->zMalloc );
+    memcpy(pMem->zMalloc, pMem->z, pMem->n);
+  }
+  if( (pMem->flags&MEM_Dyn)!=0 ){
+    assert( pMem->xDel!=0 && pMem->xDel!=SQLITE_DYNAMIC );
+    pMem->xDel((void *)(pMem->z));
+  }
+
+  pMem->z = pMem->zMalloc;
+  pMem->flags &= ~(MEM_Dyn|MEM_Ephem|MEM_Static);
+  return SQLITE_OK;
+}
+
+/*
+** Change the pMem->zMalloc allocation to be at least szNew bytes.
+** If pMem->zMalloc already meets or exceeds the requested size, this
+** routine is a no-op.
+**
+** Any prior string or blob content in the pMem object may be discarded.
+** The pMem->xDel destructor is called, if it exists.  Though MEM_Str
+** and MEM_Blob values may be discarded, MEM_Int, MEM_Real, MEM_IntReal,
+** and MEM_Null values are preserved.
+**
+** Return SQLITE_OK on success or an error code (probably SQLITE_NOMEM)
+** if unable to complete the resizing.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemClearAndResize(Mem *pMem, int szNew){
+  assert( CORRUPT_DB || szNew>0 );
+  assert( (pMem->flags & MEM_Dyn)==0 || pMem->szMalloc==0 );
+  if( pMem->szMalloc<szNew ){
+    return sqlite3VdbeMemGrow(pMem, szNew, 0);
+  }
+  assert( (pMem->flags & MEM_Dyn)==0 );
+  pMem->z = pMem->zMalloc;
+  pMem->flags &= (MEM_Null|MEM_Int|MEM_Real|MEM_IntReal);
+  return SQLITE_OK;
+}
+
+/*
+** If pMem is already a string, detect if it is a zero-terminated
+** string, or make it into one if possible, and mark it as such.
+**
+** This is an optimization.  Correct operation continues even if
+** this routine is a no-op.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemZeroTerminateIfAble(Mem *pMem){
+  if( (pMem->flags & (MEM_Str|MEM_Term|MEM_Ephem|MEM_Static))!=MEM_Str ){
+    /* pMem must be a string, and it cannot be an ephemeral or static string */
+    return;
+  }
+  if( pMem->enc!=SQLITE_UTF8 ) return;
+  if( NEVER(pMem->z==0) ) return;
+  if( pMem->flags & MEM_Dyn ){
+    if( pMem->xDel==sqlite3_free
+     && sqlite3_msize(pMem->z) >= (u64)(pMem->n+1)
+    ){
+      pMem->z[pMem->n] = 0;
+      pMem->flags |= MEM_Term;
+      return;
+    }
+    if( pMem->xDel==sqlite3RCStrUnref ){
+      /* Blindly assume that all RCStr objects are zero-terminated */
+      pMem->flags |= MEM_Term;
+      return;
+    }
+  }else if( pMem->szMalloc >= pMem->n+1 ){
+    pMem->z[pMem->n] = 0;
+    pMem->flags |= MEM_Term;
+    return;
+  }
+}
+
+/*
+** It is already known that pMem contains an unterminated string.
+** Add the zero terminator.
+**
+** Three bytes of zero are added.  In this way, there is guaranteed
+** to be a double-zero byte at an even byte boundary in order to
+** terminate a UTF16 string, even if the initial size of the buffer
+** is an odd number of bytes.
+*/
+static SQLITE_NOINLINE int vdbeMemAddTerminator(Mem *pMem){
+  if( sqlite3VdbeMemGrow(pMem, pMem->n+3, 1) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  pMem->z[pMem->n] = 0;
+  pMem->z[pMem->n+1] = 0;
+  pMem->z[pMem->n+2] = 0;
+  pMem->flags |= MEM_Term;
+  return SQLITE_OK;
+}
+
+/*
+** Change pMem so that its MEM_Str or MEM_Blob value is stored in
+** MEM.zMalloc, where it can be safely written.
+**
+** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemMakeWriteable(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  if( (pMem->flags & (MEM_Str|MEM_Blob))!=0 ){
+    if( ExpandBlob(pMem) ) return SQLITE_NOMEM;
+    if( pMem->szMalloc==0 || pMem->z!=pMem->zMalloc ){
+      int rc = vdbeMemAddTerminator(pMem);
+      if( rc ) return rc;
+    }
+  }
+  pMem->flags &= ~MEM_Ephem;
+#ifdef SQLITE_DEBUG
+  pMem->pScopyFrom = 0;
+#endif
+
+  return SQLITE_OK;
+}
+
+/*
+** If the given Mem* has a zero-filled tail, turn it into an ordinary
+** blob stored in dynamically allocated space.
+*/
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE int sqlite3VdbeMemExpandBlob(Mem *pMem){
+  int nByte;
+  assert( pMem!=0 );
+  assert( pMem->flags & MEM_Zero );
+  assert( (pMem->flags&MEM_Blob)!=0 || MemNullNochng(pMem) );
+  testcase( sqlite3_value_nochange(pMem) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+
+  /* Set nByte to the number of bytes required to store the expanded blob. */
+  nByte = pMem->n + pMem->u.nZero;
+  if( nByte<=0 ){
+    if( (pMem->flags & MEM_Blob)==0 ) return SQLITE_OK;
+    nByte = 1;
+  }
+  if( sqlite3VdbeMemGrow(pMem, nByte, 1) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( pMem->z!=0 );
+  assert( sqlite3DbMallocSize(pMem->db,pMem->z) >= nByte );
+
+  memset(&pMem->z[pMem->n], 0, pMem->u.nZero);
+  pMem->n += pMem->u.nZero;
+  pMem->flags &= ~(MEM_Zero|MEM_Term);
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Make sure the given Mem is \u0000 terminated.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemNulTerminate(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  testcase( (pMem->flags & (MEM_Term|MEM_Str))==(MEM_Term|MEM_Str) );
+  testcase( (pMem->flags & (MEM_Term|MEM_Str))==0 );
+  if( (pMem->flags & (MEM_Term|MEM_Str))!=MEM_Str ){
+    return SQLITE_OK;   /* Nothing to do */
+  }else{
+    return vdbeMemAddTerminator(pMem);
+  }
+}
+
+/*
+** Add MEM_Str to the set of representations for the given Mem.  This
+** routine is only called if pMem is a number of some kind, not a NULL
+** or a BLOB.
+**
+** Existing representations MEM_Int, MEM_Real, or MEM_IntReal are invalidated
+** if bForce is true but are retained if bForce is false.
+**
+** A MEM_Null value will never be passed to this function. This function is
+** used for converting values to text for returning to the user (i.e. via
+** sqlite3_value_text()), or for ensuring that values to be used as btree
+** keys are strings. In the former case a NULL pointer is returned the
+** user and the latter is an internal programming error.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemStringify(Mem *pMem, u8 enc, u8 bForce){
+  const int nByte = 32;
+
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !(pMem->flags&MEM_Zero) );
+  assert( !(pMem->flags&(MEM_Str|MEM_Blob)) );
+  assert( pMem->flags&(MEM_Int|MEM_Real|MEM_IntReal) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+
+  if( sqlite3VdbeMemClearAndResize(pMem, nByte) ){
+    pMem->enc = 0;
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  vdbeMemRenderNum(nByte, pMem->z, pMem);
+  assert( pMem->z!=0 );
+  assert( pMem->n==(int)sqlite3Strlen30NN(pMem->z) );
+  pMem->enc = SQLITE_UTF8;
+  pMem->flags |= MEM_Str|MEM_Term;
+  if( bForce ) pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal);
+  sqlite3VdbeChangeEncoding(pMem, enc);
+  return SQLITE_OK;
+}
+
+/*
+** Memory cell pMem contains the context of an aggregate function.
+** This routine calls the finalize method for that function.  The
+** result of the aggregate is stored back into pMem.
+**
+** Return SQLITE_ERROR if the finalizer reports an error.  SQLITE_OK
+** otherwise.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
+  sqlite3_context ctx;
+  Mem t;
+  assert( pFunc!=0 );
+  assert( pMem!=0 );
+  assert( pMem->db!=0 );
+  assert( pFunc->xFinalize!=0 );
+  assert( (pMem->flags & MEM_Null)!=0 || pFunc==pMem->u.pDef );
+  assert( sqlite3_mutex_held(pMem->db->mutex) );
+  memset(&ctx, 0, sizeof(ctx));
+  memset(&t, 0, sizeof(t));
+  t.flags = MEM_Null;
+  t.db = pMem->db;
+  ctx.pOut = &t;
+  ctx.pMem = pMem;
+  ctx.pFunc = pFunc;
+  ctx.enc = ENC(t.db);
+  pFunc->xFinalize(&ctx); /* IMP: R-24505-23230 */
+  assert( (pMem->flags & MEM_Dyn)==0 );
+  if( pMem->szMalloc>0 ) sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
+  memcpy(pMem, &t, sizeof(t));
+  return ctx.isError;
+}
+
+/*
+** Memory cell pAccum contains the context of an aggregate function.
+** This routine calls the xValue method for that function and stores
+** the results in memory cell pMem.
+**
+** SQLITE_ERROR is returned if xValue() reports an error. SQLITE_OK
+** otherwise.
+*/
+#ifndef SQLITE_OMIT_WINDOWFUNC
+SQLITE_PRIVATE int sqlite3VdbeMemAggValue(Mem *pAccum, Mem *pOut, FuncDef *pFunc){
+  sqlite3_context ctx;
+  assert( pFunc!=0 );
+  assert( pFunc->xValue!=0 );
+  assert( (pAccum->flags & MEM_Null)!=0 || pFunc==pAccum->u.pDef );
+  assert( pAccum->db!=0 );
+  assert( sqlite3_mutex_held(pAccum->db->mutex) );
+  memset(&ctx, 0, sizeof(ctx));
+  sqlite3VdbeMemSetNull(pOut);
+  ctx.pOut = pOut;
+  ctx.pMem = pAccum;
+  ctx.pFunc = pFunc;
+  ctx.enc = ENC(pAccum->db);
+  pFunc->xValue(&ctx);
+  return ctx.isError;
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** If the memory cell contains a value that must be freed by
+** invoking the external callback in Mem.xDel, then this routine
+** will free that value.  It also sets Mem.flags to MEM_Null.
+**
+** This is a helper routine for sqlite3VdbeMemSetNull() and
+** for sqlite3VdbeMemRelease().  Use those other routines as the
+** entry point for releasing Mem resources.
+*/
+static SQLITE_NOINLINE void vdbeMemClearExternAndSetNull(Mem *p){
+  assert( p->db==0 || sqlite3_mutex_held(p->db->mutex) );
+  assert( VdbeMemDynamic(p) );
+  if( p->flags&MEM_Agg ){
+    sqlite3VdbeMemFinalize(p, p->u.pDef);
+    assert( (p->flags & MEM_Agg)==0 );
+    testcase( p->flags & MEM_Dyn );
+  }
+  if( p->flags&MEM_Dyn ){
+    assert( p->xDel!=SQLITE_DYNAMIC && p->xDel!=0 );
+    p->xDel((void *)p->z);
+  }
+  p->flags = MEM_Null;
+}
+
+/*
+** Release memory held by the Mem p, both external memory cleared
+** by p->xDel and memory in p->zMalloc.
+**
+** This is a helper routine invoked by sqlite3VdbeMemRelease() in
+** the unusual case where there really is memory in p that needs
+** to be freed.
+*/
+static SQLITE_NOINLINE void vdbeMemClear(Mem *p){
+  if( VdbeMemDynamic(p) ){
+    vdbeMemClearExternAndSetNull(p);
+  }
+  if( p->szMalloc ){
+    sqlite3DbFreeNN(p->db, p->zMalloc);
+    p->szMalloc = 0;
+  }
+  p->z = 0;
+}
+
+/*
+** Release any memory resources held by the Mem.  Both the memory that is
+** free by Mem.xDel and the Mem.zMalloc allocation are freed.
+**
+** Use this routine prior to clean up prior to abandoning a Mem, or to
+** reset a Mem back to its minimum memory utilization.
+**
+** Use sqlite3VdbeMemSetNull() to release just the Mem.xDel space
+** prior to inserting new content into the Mem.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p){
+  assert( sqlite3VdbeCheckMemInvariants(p) );
+  if( VdbeMemDynamic(p) || p->szMalloc ){
+    vdbeMemClear(p);
+  }
+}
+
+/* Like sqlite3VdbeMemRelease() but faster for cases where we
+** know in advance that the Mem is not MEM_Dyn or MEM_Agg.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemReleaseMalloc(Mem *p){
+  assert( !VdbeMemDynamic(p) );
+  if( p->szMalloc ) vdbeMemClear(p);
+}
+
+/*
+** Return some kind of integer value which is the best we can do
+** at representing the value that *pMem describes as an integer.
+** If pMem is an integer, then the value is exact.  If pMem is
+** a floating-point then the value returned is the integer part.
+** If pMem is a string or blob, then we make an attempt to convert
+** it into an integer and return that.  If pMem represents an
+** an SQL-NULL value, return 0.
+**
+** If pMem represents a string value, its encoding might be changed.
+*/
+static SQLITE_NOINLINE i64 memIntValue(const Mem *pMem){
+  i64 value = 0;
+  sqlite3Atoi64(pMem->z, &value, pMem->n, pMem->enc);
+  return value;
+}
+SQLITE_PRIVATE i64 sqlite3VdbeIntValue(const Mem *pMem){
+  int flags;
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+  flags = pMem->flags;
+  if( flags & (MEM_Int|MEM_IntReal) ){
+    testcase( flags & MEM_IntReal );
+    return pMem->u.i;
+  }else if( flags & MEM_Real ){
+    return sqlite3RealToI64(pMem->u.r);
+  }else if( (flags & (MEM_Str|MEM_Blob))!=0 && pMem->z!=0 ){
+    return memIntValue(pMem);
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Return the best representation of pMem that we can get into a
+** double.  If pMem is already a double or an integer, return its
+** value.  If it is a string or blob, try to convert it to a double.
+** If it is a NULL, return 0.0.
+*/
+static SQLITE_NOINLINE double memRealValue(Mem *pMem){
+  /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+  double val = (double)0;
+  sqlite3AtoF(pMem->z, &val, pMem->n, pMem->enc);
+  return val;
+}
+SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+  if( pMem->flags & MEM_Real ){
+    return pMem->u.r;
+  }else if( pMem->flags & (MEM_Int|MEM_IntReal) ){
+    testcase( pMem->flags & MEM_IntReal );
+    return (double)pMem->u.i;
+  }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
+    return memRealValue(pMem);
+  }else{
+    /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+    return (double)0;
+  }
+}
+
+/*
+** Return 1 if pMem represents true, and return 0 if pMem represents false.
+** Return the value ifNull if pMem is NULL.
+*/
+SQLITE_PRIVATE int sqlite3VdbeBooleanValue(Mem *pMem, int ifNull){
+  testcase( pMem->flags & MEM_IntReal );
+  if( pMem->flags & (MEM_Int|MEM_IntReal) ) return pMem->u.i!=0;
+  if( pMem->flags & MEM_Null ) return ifNull;
+  return sqlite3VdbeRealValue(pMem)!=0.0;
+}
+
+/*
+** The MEM structure is already a MEM_Real or MEM_IntReal. Try to
+** make it a MEM_Int if we can.
+*/
+SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->flags & (MEM_Real|MEM_IntReal) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+  if( pMem->flags & MEM_IntReal ){
+    MemSetTypeFlag(pMem, MEM_Int);
+  }else{
+    i64 ix = sqlite3RealToI64(pMem->u.r);
+
+    /* Only mark the value as an integer if
+    **
+    **    (1) the round-trip conversion real->int->real is a no-op, and
+    **    (2) The integer is neither the largest nor the smallest
+    **        possible integer (ticket #3922)
+    **
+    ** The second and third terms in the following conditional enforces
+    ** the second condition under the assumption that addition overflow causes
+    ** values to wrap around.
+    */
+    if( pMem->u.r==ix && ix>SMALLEST_INT64 && ix<LARGEST_INT64 ){
+      pMem->u.i = ix;
+      MemSetTypeFlag(pMem, MEM_Int);
+    }
+  }
+}
+
+/*
+** Convert pMem to type integer.  Invalidate any prior representations.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemIntegerify(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+  pMem->u.i = sqlite3VdbeIntValue(pMem);
+  MemSetTypeFlag(pMem, MEM_Int);
+  return SQLITE_OK;
+}
+
+/*
+** Convert pMem so that it is of type MEM_Real.
+** Invalidate any prior representations.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+  pMem->u.r = sqlite3VdbeRealValue(pMem);
+  MemSetTypeFlag(pMem, MEM_Real);
+  return SQLITE_OK;
+}
+
+/* Compare a floating point value to an integer.  Return true if the two
+** values are the same within the precision of the floating point value.
+**
+** This function assumes that i was obtained by assignment from r1.
+**
+** For some versions of GCC on 32-bit machines, if you do the more obvious
+** comparison of "r1==(double)i" you sometimes get an answer of false even
+** though the r1 and (double)i values are bit-for-bit the same.
+*/
+SQLITE_PRIVATE int sqlite3RealSameAsInt(double r1, sqlite3_int64 i){
+  double r2 = (double)i;
+  return r1==0.0
+      || (memcmp(&r1, &r2, sizeof(r1))==0
+          && i >= -2251799813685248LL && i < 2251799813685248LL);
+}
+
+/* Convert a floating point value to its closest integer.  Do so in
+** a way that avoids 'outside the range of representable values' warnings
+** from UBSAN.
+*/
+SQLITE_PRIVATE i64 sqlite3RealToI64(double r){
+  if( r<-9223372036854774784.0 ) return SMALLEST_INT64;
+  if( r>+9223372036854774784.0 ) return LARGEST_INT64;
+  return (i64)r;
+}
+
+/*
+** Convert pMem so that it has type MEM_Real or MEM_Int.
+** Invalidate any prior representations.
+**
+** Every effort is made to force the conversion, even if the input
+** is a string that does not look completely like a number.  Convert
+** as much of the string as we can and ignore the rest.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem *pMem){
+  assert( pMem!=0 );
+  testcase( pMem->flags & MEM_Int );
+  testcase( pMem->flags & MEM_Real );
+  testcase( pMem->flags & MEM_IntReal );
+  testcase( pMem->flags & MEM_Null );
+  if( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))==0 ){
+    int rc;
+    sqlite3_int64 ix;
+    assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
+    assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+    rc = sqlite3AtoF(pMem->z, &pMem->u.r, pMem->n, pMem->enc);
+    if( ((rc==0 || rc==1) && sqlite3Atoi64(pMem->z, &ix, pMem->n, pMem->enc)<=1)
+     || sqlite3RealSameAsInt(pMem->u.r, (ix = sqlite3RealToI64(pMem->u.r)))
+    ){
+      pMem->u.i = ix;
+      MemSetTypeFlag(pMem, MEM_Int);
+    }else{
+      MemSetTypeFlag(pMem, MEM_Real);
+    }
+  }
+  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))!=0 );
+  pMem->flags &= ~(MEM_Str|MEM_Blob|MEM_Zero);
+  return SQLITE_OK;
+}
+
+/*
+** Cast the datatype of the value in pMem according to the affinity
+** "aff".  Casting is different from applying affinity in that a cast
+** is forced.  In other words, the value is converted into the desired
+** affinity even if that results in loss of data.  This routine is
+** used (for example) to implement the SQL "cast()" operator.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemCast(Mem *pMem, u8 aff, u8 encoding){
+  if( pMem->flags & MEM_Null ) return SQLITE_OK;
+  switch( aff ){
+    case SQLITE_AFF_BLOB: {   /* Really a cast to BLOB */
+      if( (pMem->flags & MEM_Blob)==0 ){
+        sqlite3ValueApplyAffinity(pMem, SQLITE_AFF_TEXT, encoding);
+        assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
+        if( pMem->flags & MEM_Str ) MemSetTypeFlag(pMem, MEM_Blob);
+      }else{
+        pMem->flags &= ~(MEM_TypeMask&~MEM_Blob);
+      }
+      break;
+    }
+    case SQLITE_AFF_NUMERIC: {
+      sqlite3VdbeMemNumerify(pMem);
+      break;
+    }
+    case SQLITE_AFF_INTEGER: {
+      sqlite3VdbeMemIntegerify(pMem);
+      break;
+    }
+    case SQLITE_AFF_REAL: {
+      sqlite3VdbeMemRealify(pMem);
+      break;
+    }
+    default: {
+      int rc;
+      assert( aff==SQLITE_AFF_TEXT );
+      assert( MEM_Str==(MEM_Blob>>3) );
+      pMem->flags |= (pMem->flags&MEM_Blob)>>3;
+      sqlite3ValueApplyAffinity(pMem, SQLITE_AFF_TEXT, encoding);
+      assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
+      pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal|MEM_Blob|MEM_Zero);
+      if( encoding!=SQLITE_UTF8 ) pMem->n &= ~1;
+      rc = sqlite3VdbeChangeEncoding(pMem, encoding);
+      if( rc ) return rc;
+      sqlite3VdbeMemZeroTerminateIfAble(pMem);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Initialize bulk memory to be a consistent Mem object.
+**
+** The minimum amount of initialization feasible is performed.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemInit(Mem *pMem, sqlite3 *db, u16 flags){
+  assert( (flags & ~MEM_TypeMask)==0 );
+  pMem->flags = flags;
+  pMem->db = db;
+  pMem->szMalloc = 0;
+}
+
+
+/*
+** Delete any previous value and set the value stored in *pMem to NULL.
+**
+** This routine calls the Mem.xDel destructor to dispose of values that
+** require the destructor.  But it preserves the Mem.zMalloc memory allocation.
+** To free all resources, use sqlite3VdbeMemRelease(), which both calls this
+** routine to invoke the destructor and deallocates Mem.zMalloc.
+**
+** Use this routine to reset the Mem prior to insert a new value.
+**
+** Use sqlite3VdbeMemRelease() to complete erase the Mem prior to abandoning it.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetNull(Mem *pMem){
+  if( VdbeMemDynamic(pMem) ){
+    vdbeMemClearExternAndSetNull(pMem);
+  }else{
+    pMem->flags = MEM_Null;
+  }
+}
+SQLITE_PRIVATE void sqlite3ValueSetNull(sqlite3_value *p){
+  sqlite3VdbeMemSetNull((Mem*)p);
+}
+
+/*
+** Delete any previous value and set the value to be a BLOB of length
+** n containing all zeros.
+*/
+#ifndef SQLITE_OMIT_INCRBLOB
+SQLITE_PRIVATE void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
+  sqlite3VdbeMemRelease(pMem);
+  pMem->flags = MEM_Blob|MEM_Zero;
+  pMem->n = 0;
+  if( n<0 ) n = 0;
+  pMem->u.nZero = n;
+  pMem->enc = SQLITE_UTF8;
+  pMem->z = 0;
+}
+#else
+SQLITE_PRIVATE int sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
+  int nByte = n>0?n:1;
+  if( sqlite3VdbeMemGrow(pMem, nByte, 0) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( pMem->z!=0 );
+  assert( sqlite3DbMallocSize(pMem->db, pMem->z)>=nByte );
+  memset(pMem->z, 0, nByte);
+  pMem->n = n>0?n:0;
+  pMem->flags = MEM_Blob;
+  pMem->enc = SQLITE_UTF8;
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** The pMem is known to contain content that needs to be destroyed prior
+** to a value change.  So invoke the destructor, then set the value to
+** a 64-bit integer.
+*/
+static SQLITE_NOINLINE void vdbeReleaseAndSetInt64(Mem *pMem, i64 val){
+  sqlite3VdbeMemSetNull(pMem);
+  pMem->u.i = val;
+  pMem->flags = MEM_Int;
+}
+
+/*
+** Delete any previous value and set the value stored in *pMem to val,
+** manifest type INTEGER.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
+  if( VdbeMemDynamic(pMem) ){
+    vdbeReleaseAndSetInt64(pMem, val);
+  }else{
+    pMem->u.i = val;
+    pMem->flags = MEM_Int;
+  }
+}
+
+/*
+** Set the iIdx'th entry of array aMem[] to contain integer value val.
+*/
+SQLITE_PRIVATE void sqlite3MemSetArrayInt64(sqlite3_value *aMem, int iIdx, i64 val){
+  sqlite3VdbeMemSetInt64(&aMem[iIdx], val);
+}
+
+/* A no-op destructor */
+SQLITE_PRIVATE void sqlite3NoopDestructor(void *p){ UNUSED_PARAMETER(p); }
+
+/*
+** Set the value stored in *pMem should already be a NULL.
+** Also store a pointer to go with it.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetPointer(
+  Mem *pMem,
+  void *pPtr,
+  const char *zPType,
+  void (*xDestructor)(void*)
+){
+  assert( pMem->flags==MEM_Null );
+  vdbeMemClear(pMem);
+  pMem->u.zPType = zPType ? zPType : "";
+  pMem->z = pPtr;
+  pMem->flags = MEM_Null|MEM_Dyn|MEM_Subtype|MEM_Term;
+  pMem->eSubtype = 'p';
+  pMem->xDel = xDestructor ? xDestructor : sqlite3NoopDestructor;
+}
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Delete any previous value and set the value stored in *pMem to val,
+** manifest type REAL.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
+  sqlite3VdbeMemSetNull(pMem);
+  if( !sqlite3IsNaN(val) ){
+    pMem->u.r = val;
+    pMem->flags = MEM_Real;
+  }
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Return true if the Mem holds a RowSet object.  This routine is intended
+** for use inside of assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemIsRowSet(const Mem *pMem){
+  return (pMem->flags&(MEM_Blob|MEM_Dyn))==(MEM_Blob|MEM_Dyn)
+         && pMem->xDel==sqlite3RowSetDelete;
+}
+#endif
+
+/*
+** Delete any previous value and set the value of pMem to be an
+** empty boolean index.
+**
+** Return SQLITE_OK on success and SQLITE_NOMEM if a memory allocation
+** error occurs.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemSetRowSet(Mem *pMem){
+  sqlite3 *db = pMem->db;
+  RowSet *p;
+  assert( db!=0 );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  sqlite3VdbeMemRelease(pMem);
+  p = sqlite3RowSetInit(db);
+  if( p==0 ) return SQLITE_NOMEM;
+  pMem->z = (char*)p;
+  pMem->flags = MEM_Blob|MEM_Dyn;
+  pMem->xDel = sqlite3RowSetDelete;
+  return SQLITE_OK;
+}
+
+/*
+** Return true if the Mem object contains a TEXT or BLOB that is
+** too large - whose size exceeds SQLITE_MAX_LENGTH.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemTooBig(Mem *p){
+  assert( p->db!=0 );
+  if( p->flags & (MEM_Str|MEM_Blob) ){
+    int n = p->n;
+    if( p->flags & MEM_Zero ){
+      n += p->u.nZero;
+    }
+    return n>p->db->aLimit[SQLITE_LIMIT_LENGTH];
+  }
+  return 0;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** This routine prepares a memory cell for modification by breaking
+** its link to a shallow copy and by marking any current shallow
+** copies of this cell as invalid.
+**
+** This is used for testing and debugging only - to help ensure that shallow
+** copies (created by OP_SCopy) are not misused.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
+  int i;
+  Mem *pX;
+  if( pMem->bScopy ){
+    for(i=1, pX=pVdbe->aMem+1; i<pVdbe->nMem; i++, pX++){
+      if( pX->pScopyFrom==pMem ){
+        u16 mFlags;
+        if( pVdbe->db->flags & SQLITE_VdbeTrace ){
+          sqlite3DebugPrintf("Invalidate R[%d] due to change in R[%d]\n",
+            (int)(pX - pVdbe->aMem), (int)(pMem - pVdbe->aMem));
+        }
+        /* If pX is marked as a shallow copy of pMem, then try to verify that
+        ** no significant changes have been made to pX since the OP_SCopy.
+        ** A significant change would indicated a missed call to this
+        ** function for pX.  Minor changes, such as adding or removing a
+        ** dual type, are allowed, as long as the underlying value is the
+        ** same. */
+        mFlags = pMem->flags & pX->flags & pX->mScopyFlags;
+        assert( (mFlags&(MEM_Int|MEM_IntReal))==0 || pMem->u.i==pX->u.i );
+
+        /* pMem is the register that is changing.  But also mark pX as
+        ** undefined so that we can quickly detect the shallow-copy error */
+        pX->flags = MEM_Undefined;
+        pX->pScopyFrom = 0;
+      }
+    }
+    pMem->bScopy = 0;
+  }
+  pMem->pScopyFrom = 0;
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** Make an shallow copy of pFrom into pTo.  Prior contents of
+** pTo are freed.  The pFrom->z field is not duplicated.  If
+** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
+** and flags gets srcType (either MEM_Ephem or MEM_Static).
+*/
+static SQLITE_NOINLINE void vdbeClrCopy(Mem *pTo, const Mem *pFrom, int eType){
+  vdbeMemClearExternAndSetNull(pTo);
+  assert( !VdbeMemDynamic(pTo) );
+  sqlite3VdbeMemShallowCopy(pTo, pFrom, eType);
+}
+SQLITE_PRIVATE void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
+  assert( !sqlite3VdbeMemIsRowSet(pFrom) );
+  assert( pTo->db==pFrom->db );
+  if( VdbeMemDynamic(pTo) ){ vdbeClrCopy(pTo,pFrom,srcType); return; }
+  memcpy(pTo, pFrom, MEMCELLSIZE);
+  if( (pFrom->flags&MEM_Static)==0 ){
+    pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
+    assert( srcType==MEM_Ephem || srcType==MEM_Static );
+    pTo->flags |= srcType;
+  }
+}
+
+/*
+** Make a full copy of pFrom into pTo.  Prior contents of pTo are
+** freed before the copy is made.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
+  int rc = SQLITE_OK;
+
+  assert( !sqlite3VdbeMemIsRowSet(pFrom) );
+  if( VdbeMemDynamic(pTo) ) vdbeMemClearExternAndSetNull(pTo);
+  memcpy(pTo, pFrom, MEMCELLSIZE);
+  pTo->flags &= ~MEM_Dyn;
+  if( pTo->flags&(MEM_Str|MEM_Blob) ){
+    if( 0==(pFrom->flags&MEM_Static) ){
+      pTo->flags |= MEM_Ephem;
+      rc = sqlite3VdbeMemMakeWriteable(pTo);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Transfer the contents of pFrom to pTo. Any existing value in pTo is
+** freed. If pFrom contains ephemeral data, a copy is made.
+**
+** pFrom contains an SQL NULL when this routine returns.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemMove(Mem *pTo, Mem *pFrom){
+  assert( pFrom->db==0 || sqlite3_mutex_held(pFrom->db->mutex) );
+  assert( pTo->db==0 || sqlite3_mutex_held(pTo->db->mutex) );
+  assert( pFrom->db==0 || pTo->db==0 || pFrom->db==pTo->db );
+
+  sqlite3VdbeMemRelease(pTo);
+  memcpy(pTo, pFrom, sizeof(Mem));
+  pFrom->flags = MEM_Null;
+  pFrom->szMalloc = 0;
+}
+
+/*
+** Change the value of a Mem to be a string or a BLOB.
+**
+** The memory management strategy depends on the value of the xDel
+** parameter. If the value passed is SQLITE_TRANSIENT, then the
+** string is copied into a (possibly existing) buffer managed by the
+** Mem structure. Otherwise, any existing buffer is freed and the
+** pointer copied.
+**
+** If the string is too large (if it exceeds the SQLITE_LIMIT_LENGTH
+** size limit) then no memory allocation occurs.  If the string can be
+** stored without allocating memory, then it is.  If a memory allocation
+** is required to store the string, then value of pMem is unchanged.  In
+** either case, SQLITE_TOOBIG is returned.
+**
+** The "enc" parameter is the text encoding for the string, or zero
+** to store a blob.
+**
+** If n is negative, then the string consists of all bytes up to but
+** excluding the first zero character.  The n parameter must be
+** non-negative for blobs.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemSetStr(
+  Mem *pMem,          /* Memory cell to set to string value */
+  const char *z,      /* String pointer */
+  i64 n,              /* Bytes in string, or negative */
+  u8 enc,             /* Encoding of z.  0 for BLOBs */
+  void (*xDel)(void*) /* Destructor function */
+){
+  i64 nByte = n;      /* New value for pMem->n */
+  int iLimit;         /* Maximum allowed string or blob size */
+  u16 flags;          /* New value for pMem->flags */
+
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( enc!=0 || n>=0 );
+
+  /* If z is a NULL pointer, set pMem to contain an SQL NULL. */
+  if( !z ){
+    sqlite3VdbeMemSetNull(pMem);
+    return SQLITE_OK;
+  }
+
+  if( pMem->db ){
+    iLimit = pMem->db->aLimit[SQLITE_LIMIT_LENGTH];
+  }else{
+    iLimit = SQLITE_MAX_LENGTH;
+  }
+  if( nByte<0 ){
+    assert( enc!=0 );
+    if( enc==SQLITE_UTF8 ){
+      nByte = strlen(z);
+    }else{
+      for(nByte=0; nByte<=iLimit && (z[nByte] | z[nByte+1]); nByte+=2){}
+    }
+    flags= MEM_Str|MEM_Term;
+  }else if( enc==0 ){
+    flags = MEM_Blob;
+    enc = SQLITE_UTF8;
+  }else{
+    flags = MEM_Str;
+  }
+  if( nByte>iLimit ){
+    if( xDel && xDel!=SQLITE_TRANSIENT ){
+      if( xDel==SQLITE_DYNAMIC ){
+        sqlite3DbFree(pMem->db, (void*)z);
+      }else{
+        xDel((void*)z);
+      }
+    }
+    sqlite3VdbeMemSetNull(pMem);
+    return sqlite3ErrorToParser(pMem->db, SQLITE_TOOBIG);
+  }
+
+  /* The following block sets the new values of Mem.z and Mem.xDel. It
+  ** also sets a flag in local variable "flags" to indicate the memory
+  ** management (one of MEM_Dyn or MEM_Static).
+  */
+  if( xDel==SQLITE_TRANSIENT ){
+    i64 nAlloc = nByte;
+    if( flags&MEM_Term ){
+      nAlloc += (enc==SQLITE_UTF8?1:2);
+    }
+    testcase( nAlloc==0 );
+    testcase( nAlloc==31 );
+    testcase( nAlloc==32 );
+    if( sqlite3VdbeMemClearAndResize(pMem, (int)MAX(nAlloc,32)) ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    memcpy(pMem->z, z, nAlloc);
+  }else{
+    sqlite3VdbeMemRelease(pMem);
+    pMem->z = (char *)z;
+    if( xDel==SQLITE_DYNAMIC ){
+      pMem->zMalloc = pMem->z;
+      pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->zMalloc);
+    }else{
+      pMem->xDel = xDel;
+      flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
+    }
+  }
+
+  pMem->n = (int)(nByte & 0x7fffffff);
+  pMem->flags = flags;
+  pMem->enc = enc;
+
+#ifndef SQLITE_OMIT_UTF16
+  if( enc>SQLITE_UTF8 && sqlite3VdbeMemHandleBom(pMem) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+#endif
+
+
+  return SQLITE_OK;
+}
+
+/*
+** Move data out of a btree key or data field and into a Mem structure.
+** The data is payload from the entry that pCur is currently pointing
+** to.  offset and amt determine what portion of the data or key to retrieve.
+** The result is written into the pMem element.
+**
+** The pMem object must have been initialized.  This routine will use
+** pMem->zMalloc to hold the content from the btree, if possible.  New
+** pMem->zMalloc space will be allocated if necessary.  The calling routine
+** is responsible for making sure that the pMem object is eventually
+** destroyed.
+**
+** If this routine fails for any reason (malloc returns NULL or unable
+** to read from the disk) then the pMem is left in an inconsistent state.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(
+  BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
+  u32 offset,       /* Offset from the start of data to return bytes from. */
+  u32 amt,          /* Number of bytes to return. */
+  Mem *pMem         /* OUT: Return data in this Mem structure. */
+){
+  int rc;
+  pMem->flags = MEM_Null;
+  if( sqlite3BtreeMaxRecordSize(pCur)<offset+amt ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( SQLITE_OK==(rc = sqlite3VdbeMemClearAndResize(pMem, amt+1)) ){
+    rc = sqlite3BtreePayload(pCur, offset, amt, pMem->z);
+    if( rc==SQLITE_OK ){
+      pMem->z[amt] = 0;   /* Overrun area used when reading malformed records */
+      pMem->flags = MEM_Blob;
+      pMem->n = (int)amt;
+    }else{
+      sqlite3VdbeMemRelease(pMem);
+    }
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3VdbeMemFromBtreeZeroOffset(
+  BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
+  u32 amt,          /* Number of bytes to return. */
+  Mem *pMem         /* OUT: Return data in this Mem structure. */
+){
+  u32 available = 0;  /* Number of bytes available on the local btree page */
+  int rc = SQLITE_OK; /* Return code */
+
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+  assert( !VdbeMemDynamic(pMem) );
+
+  /* Note: the calls to BtreeKeyFetch() and DataFetch() below assert()
+  ** that both the BtShared and database handle mutexes are held. */
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  pMem->z = (char *)sqlite3BtreePayloadFetch(pCur, &available);
+  assert( pMem->z!=0 );
+
+  if( amt<=available ){
+    pMem->flags = MEM_Blob|MEM_Ephem;
+    pMem->n = (int)amt;
+  }else{
+    rc = sqlite3VdbeMemFromBtree(pCur, 0, amt, pMem);
+  }
+
+  return rc;
+}
+
+/*
+** The pVal argument is known to be a value other than NULL.
+** Convert it into a string with encoding enc and return a pointer
+** to a zero-terminated version of that string.
+*/
+static SQLITE_NOINLINE const void *valueToText(sqlite3_value* pVal, u8 enc){
+  assert( pVal!=0 );
+  assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
+  assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
+  assert( !sqlite3VdbeMemIsRowSet(pVal) );
+  assert( (pVal->flags & (MEM_Null))==0 );
+  if( pVal->flags & (MEM_Blob|MEM_Str) ){
+    if( ExpandBlob(pVal) ) return 0;
+    pVal->flags |= MEM_Str;
+    if( pVal->enc != (enc & ~SQLITE_UTF16_ALIGNED) ){
+      sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
+    }
+    if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
+      assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
+      if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
+        return 0;
+      }
+    }
+    sqlite3VdbeMemNulTerminate(pVal); /* IMP: R-31275-44060 */
+  }else{
+    sqlite3VdbeMemStringify(pVal, enc, 0);
+    assert( 0==(1&SQLITE_PTR_TO_INT(pVal->z)) );
+  }
+  assert(pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) || pVal->db==0
+              || pVal->db->mallocFailed );
+  if( pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) ){
+    assert( sqlite3VdbeMemValidStrRep(pVal) );
+    return pVal->z;
+  }else{
+    return 0;
+  }
+}
+
+/* This function is only available internally, it is not part of the
+** external API. It works in a similar way to sqlite3_value_text(),
+** except the data returned is in the encoding specified by the second
+** parameter, which must be one of SQLITE_UTF16BE, SQLITE_UTF16LE or
+** SQLITE_UTF8.
+**
+** (2006-02-16:)  The enc value can be or-ed with SQLITE_UTF16_ALIGNED.
+** If that is the case, then the result must be aligned on an even byte
+** boundary.
+*/
+SQLITE_PRIVATE const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
+  if( !pVal ) return 0;
+  assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
+  assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
+  assert( !sqlite3VdbeMemIsRowSet(pVal) );
+  if( (pVal->flags&(MEM_Str|MEM_Term))==(MEM_Str|MEM_Term) && pVal->enc==enc ){
+    assert( sqlite3VdbeMemValidStrRep(pVal) );
+    return pVal->z;
+  }
+  if( pVal->flags&MEM_Null ){
+    return 0;
+  }
+  return valueToText(pVal, enc);
+}
+
+/* Return true if sqlit3_value object pVal is a string or blob value
+** that uses the destructor specified in the second argument.
+**
+** TODO:  Maybe someday promote this interface into a published API so
+** that third-party extensions can get access to it?
+*/
+SQLITE_PRIVATE int sqlite3ValueIsOfClass(const sqlite3_value *pVal, void(*xFree)(void*)){
+  if( ALWAYS(pVal!=0)
+   && ALWAYS((pVal->flags & (MEM_Str|MEM_Blob))!=0)
+   && (pVal->flags & MEM_Dyn)!=0
+   && pVal->xDel==xFree
+  ){
+    return 1;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Create a new sqlite3_value object.
+*/
+SQLITE_PRIVATE sqlite3_value *sqlite3ValueNew(sqlite3 *db){
+  Mem *p = sqlite3DbMallocZero(db, sizeof(*p));
+  if( p ){
+    p->flags = MEM_Null;
+    p->db = db;
+  }
+  return p;
+}
+
+/*
+** Context object passed by sqlite3Stat4ProbeSetValue() through to
+** valueNew(). See comments above valueNew() for details.
+*/
+struct ValueNewStat4Ctx {
+  Parse *pParse;
+  Index *pIdx;
+  UnpackedRecord **ppRec;
+  int iVal;
+};
+
+/*
+** Allocate and return a pointer to a new sqlite3_value object. If
+** the second argument to this function is NULL, the object is allocated
+** by calling sqlite3ValueNew().
+**
+** Otherwise, if the second argument is non-zero, then this function is
+** being called indirectly by sqlite3Stat4ProbeSetValue(). If it has not
+** already been allocated, allocate the UnpackedRecord structure that
+** that function will return to its caller here. Then return a pointer to
+** an sqlite3_value within the UnpackedRecord.a[] array.
+*/
+static sqlite3_value *valueNew(sqlite3 *db, struct ValueNewStat4Ctx *p){
+#ifdef SQLITE_ENABLE_STAT4
+  if( p ){
+    UnpackedRecord *pRec = p->ppRec[0];
+
+    if( pRec==0 ){
+      Index *pIdx = p->pIdx;      /* Index being probed */
+      int nByte;                  /* Bytes of space to allocate */
+      int i;                      /* Counter variable */
+      int nCol = pIdx->nColumn;   /* Number of index columns including rowid */
+
+      nByte = sizeof(Mem) * nCol + ROUND8(sizeof(UnpackedRecord));
+      pRec = (UnpackedRecord*)sqlite3DbMallocZero(db, nByte);
+      if( pRec ){
+        pRec->pKeyInfo = sqlite3KeyInfoOfIndex(p->pParse, pIdx);
+        if( pRec->pKeyInfo ){
+          assert( pRec->pKeyInfo->nAllField==nCol );
+          assert( pRec->pKeyInfo->enc==ENC(db) );
+          pRec->aMem = (Mem *)((u8*)pRec + ROUND8(sizeof(UnpackedRecord)));
+          for(i=0; i<nCol; i++){
+            pRec->aMem[i].flags = MEM_Null;
+            pRec->aMem[i].db = db;
+          }
+        }else{
+          sqlite3DbFreeNN(db, pRec);
+          pRec = 0;
+        }
+      }
+      if( pRec==0 ) return 0;
+      p->ppRec[0] = pRec;
+    }
+
+    pRec->nField = p->iVal+1;
+    sqlite3VdbeMemSetNull(&pRec->aMem[p->iVal]);
+    return &pRec->aMem[p->iVal];
+  }
+#else
+  UNUSED_PARAMETER(p);
+#endif /* defined(SQLITE_ENABLE_STAT4) */
+  return sqlite3ValueNew(db);
+}
+
+/*
+** The expression object indicated by the second argument is guaranteed
+** to be a scalar SQL function. If
+**
+**   * all function arguments are SQL literals,
+**   * one of the SQLITE_FUNC_CONSTANT or _SLOCHNG function flags is set, and
+**   * the SQLITE_FUNC_NEEDCOLL function flag is not set,
+**
+** then this routine attempts to invoke the SQL function. Assuming no
+** error occurs, output parameter (*ppVal) is set to point to a value
+** object containing the result before returning SQLITE_OK.
+**
+** Affinity aff is applied to the result of the function before returning.
+** If the result is a text value, the sqlite3_value object uses encoding
+** enc.
+**
+** If the conditions above are not met, this function returns SQLITE_OK
+** and sets (*ppVal) to NULL. Or, if an error occurs, (*ppVal) is set to
+** NULL and an SQLite error code returned.
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static int valueFromFunction(
+  sqlite3 *db,                    /* The database connection */
+  const Expr *p,                  /* The expression to evaluate */
+  u8 enc,                         /* Encoding to use */
+  u8 aff,                         /* Affinity to use */
+  sqlite3_value **ppVal,          /* Write the new value here */
+  struct ValueNewStat4Ctx *pCtx   /* Second argument for valueNew() */
+){
+  sqlite3_context ctx;            /* Context object for function invocation */
+  sqlite3_value **apVal = 0;      /* Function arguments */
+  int nVal = 0;                   /* Size of apVal[] array */
+  FuncDef *pFunc = 0;             /* Function definition */
+  sqlite3_value *pVal = 0;        /* New value */
+  int rc = SQLITE_OK;             /* Return code */
+  ExprList *pList = 0;            /* Function arguments */
+  int i;                          /* Iterator variable */
+
+  assert( pCtx!=0 );
+  assert( (p->flags & EP_TokenOnly)==0 );
+  assert( ExprUseXList(p) );
+  pList = p->x.pList;
+  if( pList ) nVal = pList->nExpr;
+  assert( !ExprHasProperty(p, EP_IntValue) );
+  pFunc = sqlite3FindFunction(db, p->u.zToken, nVal, enc, 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+  if( pFunc==0 ) return SQLITE_OK;
+#endif
+  assert( pFunc );
+  if( (pFunc->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG))==0
+   || (pFunc->funcFlags & (SQLITE_FUNC_NEEDCOLL|SQLITE_FUNC_RUNONLY))!=0
+  ){
+    return SQLITE_OK;
+  }
+
+  if( pList ){
+    apVal = (sqlite3_value**)sqlite3DbMallocZero(db, sizeof(apVal[0]) * nVal);
+    if( apVal==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto value_from_function_out;
+    }
+    for(i=0; i<nVal; i++){
+      rc = sqlite3Stat4ValueFromExpr(pCtx->pParse, pList->a[i].pExpr, aff,
+                                     &apVal[i]);
+      if( apVal[i]==0 || rc!=SQLITE_OK ) goto value_from_function_out;
+    }
+  }
+
+  pVal = valueNew(db, pCtx);
+  if( pVal==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto value_from_function_out;
+  }
+
+  memset(&ctx, 0, sizeof(ctx));
+  ctx.pOut = pVal;
+  ctx.pFunc = pFunc;
+  ctx.enc = ENC(db);
+  pFunc->xSFunc(&ctx, nVal, apVal);
+  if( ctx.isError ){
+    rc = ctx.isError;
+    sqlite3ErrorMsg(pCtx->pParse, "%s", sqlite3_value_text(pVal));
+  }else{
+    sqlite3ValueApplyAffinity(pVal, aff, SQLITE_UTF8);
+    assert( rc==SQLITE_OK );
+    rc = sqlite3VdbeChangeEncoding(pVal, enc);
+    if( NEVER(rc==SQLITE_OK && sqlite3VdbeMemTooBig(pVal)) ){
+      rc = SQLITE_TOOBIG;
+      pCtx->pParse->nErr++;
+    }
+  }
+
+ value_from_function_out:
+  if( rc!=SQLITE_OK ){
+    pVal = 0;
+    pCtx->pParse->rc = rc;
+  }
+  if( apVal ){
+    for(i=0; i<nVal; i++){
+      sqlite3ValueFree(apVal[i]);
+    }
+    sqlite3DbFreeNN(db, apVal);
+  }
+
+  *ppVal = pVal;
+  return rc;
+}
+#else
+# define valueFromFunction(a,b,c,d,e,f) SQLITE_OK
+#endif /* defined(SQLITE_ENABLE_STAT4) */
+
+/*
+** Extract a value from the supplied expression in the manner described
+** above sqlite3ValueFromExpr(). Allocate the sqlite3_value object
+** using valueNew().
+**
+** If pCtx is NULL and an error occurs after the sqlite3_value object
+** has been allocated, it is freed before returning. Or, if pCtx is not
+** NULL, it is assumed that the caller will free any allocated object
+** in all cases.
+*/
+static int valueFromExpr(
+  sqlite3 *db,                    /* The database connection */
+  const Expr *pExpr,              /* The expression to evaluate */
+  u8 enc,                         /* Encoding to use */
+  u8 affinity,                    /* Affinity to use */
+  sqlite3_value **ppVal,          /* Write the new value here */
+  struct ValueNewStat4Ctx *pCtx   /* Second argument for valueNew() */
+){
+  int op;
+  char *zVal = 0;
+  sqlite3_value *pVal = 0;
+  int negInt = 1;
+  const char *zNeg = "";
+  int rc = SQLITE_OK;
+
+  assert( pExpr!=0 );
+  while( (op = pExpr->op)==TK_UPLUS || op==TK_SPAN ) pExpr = pExpr->pLeft;
+  if( op==TK_REGISTER ) op = pExpr->op2;
+
+  /* Compressed expressions only appear when parsing the DEFAULT clause
+  ** on a table column definition, and hence only when pCtx==0.  This
+  ** check ensures that an EP_TokenOnly expression is never passed down
+  ** into valueFromFunction(). */
+  assert( (pExpr->flags & EP_TokenOnly)==0 || pCtx==0 );
+
+  if( op==TK_CAST ){
+    u8 aff;
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    aff = sqlite3AffinityType(pExpr->u.zToken,0);
+    rc = valueFromExpr(db, pExpr->pLeft, enc, aff, ppVal, pCtx);
+    testcase( rc!=SQLITE_OK );
+    if( *ppVal ){
+#ifdef SQLITE_ENABLE_STAT4
+      rc = ExpandBlob(*ppVal);
+#else
+      /* zero-blobs only come from functions, not literal values.  And
+      ** functions are only processed under STAT4 */
+      assert( (ppVal[0][0].flags & MEM_Zero)==0 );
+#endif
+      sqlite3VdbeMemCast(*ppVal, aff, enc);
+      sqlite3ValueApplyAffinity(*ppVal, affinity, enc);
+    }
+    return rc;
+  }
+
+  /* Handle negative integers in a single step.  This is needed in the
+  ** case when the value is -9223372036854775808. Except - do not do this
+  ** for hexadecimal literals.  */
+  if( op==TK_UMINUS ){
+    Expr *pLeft = pExpr->pLeft;
+    if( (pLeft->op==TK_INTEGER || pLeft->op==TK_FLOAT) ){
+      if( ExprHasProperty(pLeft, EP_IntValue)
+       || pLeft->u.zToken[0]!='0' || (pLeft->u.zToken[1] & ~0x20)!='X'
+      ){
+        pExpr = pLeft;
+        op = pExpr->op;
+        negInt = -1;
+        zNeg = "-";
+      }
+    }
+  }
+
+  if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
+    pVal = valueNew(db, pCtx);
+    if( pVal==0 ) goto no_mem;
+    if( ExprHasProperty(pExpr, EP_IntValue) ){
+      sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue*negInt);
+    }else{
+      i64 iVal;
+      if( op==TK_INTEGER && 0==sqlite3DecOrHexToI64(pExpr->u.zToken, &iVal) ){
+        sqlite3VdbeMemSetInt64(pVal, iVal*negInt);
+      }else{
+        zVal = sqlite3MPrintf(db, "%s%s", zNeg, pExpr->u.zToken);
+        if( zVal==0 ) goto no_mem;
+        sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
+      }
+    }
+    if( affinity==SQLITE_AFF_BLOB ){
+      if( op==TK_FLOAT ){
+        assert( pVal && pVal->z && pVal->flags==(MEM_Str|MEM_Term) );
+        sqlite3AtoF(pVal->z, &pVal->u.r, pVal->n, SQLITE_UTF8);
+        pVal->flags = MEM_Real;
+      }else if( op==TK_INTEGER ){
+        /* This case is required by -9223372036854775808 and other strings
+        ** that look like integers but cannot be handled by the
+        ** sqlite3DecOrHexToI64() call above.  */
+        sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
+      }
+    }else{
+      sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
+    }
+    assert( (pVal->flags & MEM_IntReal)==0 );
+    if( pVal->flags & (MEM_Int|MEM_IntReal|MEM_Real) ){
+      testcase( pVal->flags & MEM_Int );
+      testcase( pVal->flags & MEM_Real );
+      pVal->flags &= ~MEM_Str;
+    }
+    if( enc!=SQLITE_UTF8 ){
+      rc = sqlite3VdbeChangeEncoding(pVal, enc);
+    }
+  }else if( op==TK_UMINUS ) {
+    /* This branch happens for multiple negative signs.  Ex: -(-5) */
+    if( SQLITE_OK==valueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal,pCtx)
+     && pVal!=0
+    ){
+      sqlite3VdbeMemNumerify(pVal);
+      if( pVal->flags & MEM_Real ){
+        pVal->u.r = -pVal->u.r;
+      }else if( pVal->u.i==SMALLEST_INT64 ){
+#ifndef SQLITE_OMIT_FLOATING_POINT
+        pVal->u.r = -(double)SMALLEST_INT64;
+#else
+        pVal->u.r = LARGEST_INT64;
+#endif
+        MemSetTypeFlag(pVal, MEM_Real);
+      }else{
+        pVal->u.i = -pVal->u.i;
+      }
+      sqlite3ValueApplyAffinity(pVal, affinity, enc);
+    }
+  }else if( op==TK_NULL ){
+    pVal = valueNew(db, pCtx);
+    if( pVal==0 ) goto no_mem;
+    sqlite3VdbeMemSetNull(pVal);
+  }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+  else if( op==TK_BLOB ){
+    int nVal;
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
+    assert( pExpr->u.zToken[1]=='\'' );
+    pVal = valueNew(db, pCtx);
+    if( !pVal ) goto no_mem;
+    zVal = &pExpr->u.zToken[2];
+    nVal = sqlite3Strlen30(zVal)-1;
+    assert( zVal[nVal]=='\'' );
+    sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
+                         0, SQLITE_DYNAMIC);
+  }
+#endif
+#ifdef SQLITE_ENABLE_STAT4
+  else if( op==TK_FUNCTION && pCtx!=0 ){
+    rc = valueFromFunction(db, pExpr, enc, affinity, &pVal, pCtx);
+  }
+#endif
+  else if( op==TK_TRUEFALSE ){
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    pVal = valueNew(db, pCtx);
+    if( pVal ){
+      pVal->flags = MEM_Int;
+      pVal->u.i = pExpr->u.zToken[4]==0;
+      sqlite3ValueApplyAffinity(pVal, affinity, enc);
+    }
+  }
+
+  *ppVal = pVal;
+  return rc;
+
+no_mem:
+#ifdef SQLITE_ENABLE_STAT4
+  if( pCtx==0 || NEVER(pCtx->pParse->nErr==0) )
+#endif
+    sqlite3OomFault(db);
+  sqlite3DbFree(db, zVal);
+  assert( *ppVal==0 );
+#ifdef SQLITE_ENABLE_STAT4
+  if( pCtx==0 ) sqlite3ValueFree(pVal);
+#else
+  assert( pCtx==0 ); sqlite3ValueFree(pVal);
+#endif
+  return SQLITE_NOMEM_BKPT;
+}
+
+/*
+** Create a new sqlite3_value object, containing the value of pExpr.
+**
+** This only works for very simple expressions that consist of one constant
+** token (i.e. "5", "5.1", "'a string'"). If the expression can
+** be converted directly into a value, then the value is allocated and
+** a pointer written to *ppVal. The caller is responsible for deallocating
+** the value by passing it to sqlite3ValueFree() later on. If the expression
+** cannot be converted to a value, then *ppVal is set to NULL.
+*/
+SQLITE_PRIVATE int sqlite3ValueFromExpr(
+  sqlite3 *db,              /* The database connection */
+  const Expr *pExpr,        /* The expression to evaluate */
+  u8 enc,                   /* Encoding to use */
+  u8 affinity,              /* Affinity to use */
+  sqlite3_value **ppVal     /* Write the new value here */
+){
+  return pExpr ? valueFromExpr(db, pExpr, enc, affinity, ppVal, 0) : 0;
+}
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Attempt to extract a value from pExpr and use it to construct *ppVal.
+**
+** If pAlloc is not NULL, then an UnpackedRecord object is created for
+** pAlloc if one does not exist and the new value is added to the
+** UnpackedRecord object.
+**
+** A value is extracted in the following cases:
+**
+**  * (pExpr==0). In this case the value is assumed to be an SQL NULL,
+**
+**  * The expression is a bound variable, and this is a reprepare, or
+**
+**  * The expression is a literal value.
+**
+** On success, *ppVal is made to point to the extracted value.  The caller
+** is responsible for ensuring that the value is eventually freed.
+*/
+static int stat4ValueFromExpr(
+  Parse *pParse,                  /* Parse context */
+  Expr *pExpr,                    /* The expression to extract a value from */
+  u8 affinity,                    /* Affinity to use */
+  struct ValueNewStat4Ctx *pAlloc,/* How to allocate space.  Or NULL */
+  sqlite3_value **ppVal           /* OUT: New value object (or NULL) */
+){
+  int rc = SQLITE_OK;
+  sqlite3_value *pVal = 0;
+  sqlite3 *db = pParse->db;
+
+  /* Skip over any TK_COLLATE nodes */
+  pExpr = sqlite3ExprSkipCollate(pExpr);
+
+  assert( pExpr==0 || pExpr->op!=TK_REGISTER || pExpr->op2!=TK_VARIABLE );
+  if( !pExpr ){
+    pVal = valueNew(db, pAlloc);
+    if( pVal ){
+      sqlite3VdbeMemSetNull((Mem*)pVal);
+    }
+  }else if( pExpr->op==TK_VARIABLE && (db->flags & SQLITE_EnableQPSG)==0 ){
+    Vdbe *v;
+    int iBindVar = pExpr->iColumn;
+    sqlite3VdbeSetVarmask(pParse->pVdbe, iBindVar);
+    if( (v = pParse->pReprepare)!=0 ){
+      pVal = valueNew(db, pAlloc);
+      if( pVal ){
+        rc = sqlite3VdbeMemCopy((Mem*)pVal, &v->aVar[iBindVar-1]);
+        sqlite3ValueApplyAffinity(pVal, affinity, ENC(db));
+        pVal->db = pParse->db;
+      }
+    }
+  }else{
+    rc = valueFromExpr(db, pExpr, ENC(db), affinity, &pVal, pAlloc);
+  }
+
+  assert( pVal==0 || pVal->db==db );
+  *ppVal = pVal;
+  return rc;
+}
+
+/*
+** This function is used to allocate and populate UnpackedRecord
+** structures intended to be compared against sample index keys stored
+** in the sqlite_stat4 table.
+**
+** A single call to this function populates zero or more fields of the
+** record starting with field iVal (fields are numbered from left to
+** right starting with 0). A single field is populated if:
+**
+**  * (pExpr==0). In this case the value is assumed to be an SQL NULL,
+**
+**  * The expression is a bound variable, and this is a reprepare, or
+**
+**  * The sqlite3ValueFromExpr() function is able to extract a value
+**    from the expression (i.e. the expression is a literal value).
+**
+** Or, if pExpr is a TK_VECTOR, one field is populated for each of the
+** vector components that match either of the two latter criteria listed
+** above.
+**
+** Before any value is appended to the record, the affinity of the
+** corresponding column within index pIdx is applied to it. Before
+** this function returns, output parameter *pnExtract is set to the
+** number of values appended to the record.
+**
+** When this function is called, *ppRec must either point to an object
+** allocated by an earlier call to this function, or must be NULL. If it
+** is NULL and a value can be successfully extracted, a new UnpackedRecord
+** is allocated (and *ppRec set to point to it) before returning.
+**
+** Unless an error is encountered, SQLITE_OK is returned. It is not an
+** error if a value cannot be extracted from pExpr. If an error does
+** occur, an SQLite error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3Stat4ProbeSetValue(
+  Parse *pParse,                  /* Parse context */
+  Index *pIdx,                    /* Index being probed */
+  UnpackedRecord **ppRec,         /* IN/OUT: Probe record */
+  Expr *pExpr,                    /* The expression to extract a value from */
+  int nElem,                      /* Maximum number of values to append */
+  int iVal,                       /* Array element to populate */
+  int *pnExtract                  /* OUT: Values appended to the record */
+){
+  int rc = SQLITE_OK;
+  int nExtract = 0;
+
+  if( pExpr==0 || pExpr->op!=TK_SELECT ){
+    int i;
+    struct ValueNewStat4Ctx alloc;
+
+    alloc.pParse = pParse;
+    alloc.pIdx = pIdx;
+    alloc.ppRec = ppRec;
+
+    for(i=0; i<nElem; i++){
+      sqlite3_value *pVal = 0;
+      Expr *pElem = (pExpr ? sqlite3VectorFieldSubexpr(pExpr, i) : 0);
+      u8 aff = sqlite3IndexColumnAffinity(pParse->db, pIdx, iVal+i);
+      alloc.iVal = iVal+i;
+      rc = stat4ValueFromExpr(pParse, pElem, aff, &alloc, &pVal);
+      if( !pVal ) break;
+      nExtract++;
+    }
+  }
+
+  *pnExtract = nExtract;
+  return rc;
+}
+
+/*
+** Attempt to extract a value from expression pExpr using the methods
+** as described for sqlite3Stat4ProbeSetValue() above.
+**
+** If successful, set *ppVal to point to a new value object and return
+** SQLITE_OK. If no value can be extracted, but no other error occurs
+** (e.g. OOM), return SQLITE_OK and set *ppVal to NULL. Or, if an error
+** does occur, return an SQLite error code. The final value of *ppVal
+** is undefined in this case.
+*/
+SQLITE_PRIVATE int sqlite3Stat4ValueFromExpr(
+  Parse *pParse,                  /* Parse context */
+  Expr *pExpr,                    /* The expression to extract a value from */
+  u8 affinity,                    /* Affinity to use */
+  sqlite3_value **ppVal           /* OUT: New value object (or NULL) */
+){
+  return stat4ValueFromExpr(pParse, pExpr, affinity, 0, ppVal);
+}
+
+/*
+** Extract the iCol-th column from the nRec-byte record in pRec.  Write
+** the column value into *ppVal.  If *ppVal is initially NULL then a new
+** sqlite3_value object is allocated.
+**
+** If *ppVal is initially NULL then the caller is responsible for
+** ensuring that the value written into *ppVal is eventually freed.
+*/
+SQLITE_PRIVATE int sqlite3Stat4Column(
+  sqlite3 *db,                    /* Database handle */
+  const void *pRec,               /* Pointer to buffer containing record */
+  int nRec,                       /* Size of buffer pRec in bytes */
+  int iCol,                       /* Column to extract */
+  sqlite3_value **ppVal           /* OUT: Extracted value */
+){
+  u32 t = 0;                      /* a column type code */
+  u32 nHdr;                       /* Size of the header in the record */
+  u32 iHdr;                       /* Next unread header byte */
+  i64 iField;                     /* Next unread data byte */
+  u32 szField = 0;                /* Size of the current data field */
+  int i;                          /* Column index */
+  u8 *a = (u8*)pRec;              /* Typecast byte array */
+  Mem *pMem = *ppVal;             /* Write result into this Mem object */
+
+  assert( iCol>0 );
+  iHdr = getVarint32(a, nHdr);
+  if( nHdr>(u32)nRec || iHdr>=nHdr ) return SQLITE_CORRUPT_BKPT;
+  iField = nHdr;
+  for(i=0; i<=iCol; i++){
+    iHdr += getVarint32(&a[iHdr], t);
+    testcase( iHdr==nHdr );
+    testcase( iHdr==nHdr+1 );
+    if( iHdr>nHdr ) return SQLITE_CORRUPT_BKPT;
+    szField = sqlite3VdbeSerialTypeLen(t);
+    iField += szField;
+  }
+  testcase( iField==nRec );
+  testcase( iField==nRec+1 );
+  if( iField>nRec ) return SQLITE_CORRUPT_BKPT;
+  if( pMem==0 ){
+    pMem = *ppVal = sqlite3ValueNew(db);
+    if( pMem==0 ) return SQLITE_NOMEM_BKPT;
+  }
+  sqlite3VdbeSerialGet(&a[iField-szField], t, pMem);
+  pMem->enc = ENC(db);
+  return SQLITE_OK;
+}
+
+/*
+** Unless it is NULL, the argument must be an UnpackedRecord object returned
+** by an earlier call to sqlite3Stat4ProbeSetValue(). This call deletes
+** the object.
+*/
+SQLITE_PRIVATE void sqlite3Stat4ProbeFree(UnpackedRecord *pRec){
+  if( pRec ){
+    int i;
+    int nCol = pRec->pKeyInfo->nAllField;
+    Mem *aMem = pRec->aMem;
+    sqlite3 *db = aMem[0].db;
+    for(i=0; i<nCol; i++){
+      sqlite3VdbeMemRelease(&aMem[i]);
+    }
+    sqlite3KeyInfoUnref(pRec->pKeyInfo);
+    sqlite3DbFreeNN(db, pRec);
+  }
+}
+#endif /* ifdef SQLITE_ENABLE_STAT4 */
+
+/*
+** Change the string value of an sqlite3_value object
+*/
+SQLITE_PRIVATE void sqlite3ValueSetStr(
+  sqlite3_value *v,     /* Value to be set */
+  int n,                /* Length of string z */
+  const void *z,        /* Text of the new string */
+  u8 enc,               /* Encoding to use */
+  void (*xDel)(void*)   /* Destructor for the string */
+){
+  if( v ) sqlite3VdbeMemSetStr((Mem *)v, z, n, enc, xDel);
+}
+
+/*
+** Free an sqlite3_value object
+*/
+SQLITE_PRIVATE void sqlite3ValueFree(sqlite3_value *v){
+  if( !v ) return;
+  sqlite3VdbeMemRelease((Mem *)v);
+  sqlite3DbFreeNN(((Mem*)v)->db, v);
+}
+
+/*
+** The sqlite3ValueBytes() routine returns the number of bytes in the
+** sqlite3_value object assuming that it uses the encoding "enc".
+** The valueBytes() routine is a helper function.
+*/
+static SQLITE_NOINLINE int valueBytes(sqlite3_value *pVal, u8 enc){
+  return valueToText(pVal, enc)!=0 ? pVal->n : 0;
+}
+SQLITE_PRIVATE int sqlite3ValueBytes(sqlite3_value *pVal, u8 enc){
+  Mem *p = (Mem*)pVal;
+  assert( (p->flags & MEM_Null)==0 || (p->flags & (MEM_Str|MEM_Blob))==0 );
+  if( (p->flags & MEM_Str)!=0 && pVal->enc==enc ){
+    return p->n;
+  }
+  if( (p->flags & MEM_Str)!=0 && enc!=SQLITE_UTF8 && pVal->enc!=SQLITE_UTF8 ){
+    return p->n;
+  }
+  if( (p->flags & MEM_Blob)!=0 ){
+    if( p->flags & MEM_Zero ){
+      return p->n + p->u.nZero;
+    }else{
+      return p->n;
+    }
+  }
+  if( p->flags & MEM_Null ) return 0;
+  return valueBytes(pVal, enc);
+}
+
+/************** End of vdbemem.c *********************************************/
+/************** Begin file vdbeaux.c *****************************************/
+/*
+** 2003 September 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used for creating, destroying, and populating
+** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+/* Forward references */
+static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef);
+static void vdbeFreeOpArray(sqlite3 *, Op *, int);
+
+/*
+** Create a new virtual database engine.
+*/
+SQLITE_PRIVATE Vdbe *sqlite3VdbeCreate(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  Vdbe *p;
+  p = sqlite3DbMallocRawNN(db, sizeof(Vdbe) );
+  if( p==0 ) return 0;
+  memset(&p->aOp, 0, sizeof(Vdbe)-offsetof(Vdbe,aOp));
+  p->db = db;
+  if( db->pVdbe ){
+    db->pVdbe->ppVPrev = &p->pVNext;
+  }
+  p->pVNext = db->pVdbe;
+  p->ppVPrev = &db->pVdbe;
+  db->pVdbe = p;
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  p->pParse = pParse;
+  pParse->pVdbe = p;
+  assert( pParse->aLabel==0 );
+  assert( pParse->nLabel==0 );
+  assert( p->nOpAlloc==0 );
+  assert( pParse->szOpAlloc==0 );
+  sqlite3VdbeAddOp2(p, OP_Init, 0, 1);
+  return p;
+}
+
+/*
+** Return the Parse object that owns a Vdbe object.
+*/
+SQLITE_PRIVATE Parse *sqlite3VdbeParser(Vdbe *p){
+  return p->pParse;
+}
+
+/*
+** Change the error string stored in Vdbe.zErrMsg
+*/
+SQLITE_PRIVATE void sqlite3VdbeError(Vdbe *p, const char *zFormat, ...){
+  va_list ap;
+  sqlite3DbFree(p->db, p->zErrMsg);
+  va_start(ap, zFormat);
+  p->zErrMsg = sqlite3VMPrintf(p->db, zFormat, ap);
+  va_end(ap);
+}
+
+/*
+** Remember the SQL string for a prepared statement.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetSql(Vdbe *p, const char *z, int n, u8 prepFlags){
+  if( p==0 ) return;
+  p->prepFlags = prepFlags;
+  if( (prepFlags & SQLITE_PREPARE_SAVESQL)==0 ){
+    p->expmask = 0;
+  }
+  assert( p->zSql==0 );
+  p->zSql = sqlite3DbStrNDup(p->db, z, n);
+}
+
+#ifdef SQLITE_ENABLE_NORMALIZE
+/*
+** Add a new element to the Vdbe->pDblStr list.
+*/
+SQLITE_PRIVATE void sqlite3VdbeAddDblquoteStr(sqlite3 *db, Vdbe *p, const char *z){
+  if( p ){
+    int n = sqlite3Strlen30(z);
+    DblquoteStr *pStr = sqlite3DbMallocRawNN(db,
+                            sizeof(*pStr)+n+1-sizeof(pStr->z));
+    if( pStr ){
+      pStr->pNextStr = p->pDblStr;
+      p->pDblStr = pStr;
+      memcpy(pStr->z, z, n+1);
+    }
+  }
+}
+#endif
+
+#ifdef SQLITE_ENABLE_NORMALIZE
+/*
+** zId of length nId is a double-quoted identifier.  Check to see if
+** that identifier is really used as a string literal.
+*/
+SQLITE_PRIVATE int sqlite3VdbeUsesDoubleQuotedString(
+  Vdbe *pVdbe,            /* The prepared statement */
+  const char *zId         /* The double-quoted identifier, already dequoted */
+){
+  DblquoteStr *pStr;
+  assert( zId!=0 );
+  if( pVdbe->pDblStr==0 ) return 0;
+  for(pStr=pVdbe->pDblStr; pStr; pStr=pStr->pNextStr){
+    if( strcmp(zId, pStr->z)==0 ) return 1;
+  }
+  return 0;
+}
+#endif
+
+/*
+** Swap byte-code between two VDBE structures.
+**
+** This happens after pB was previously run and returned
+** SQLITE_SCHEMA.  The statement was then reprepared in pA.
+** This routine transfers the new bytecode in pA over to pB
+** so that pB can be run again.  The old pB byte code is
+** moved back to pA so that it will be cleaned up when pA is
+** finalized.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSwap(Vdbe *pA, Vdbe *pB){
+  Vdbe tmp, *pTmp, **ppTmp;
+  char *zTmp;
+  assert( pA->db==pB->db );
+  tmp = *pA;
+  *pA = *pB;
+  *pB = tmp;
+  pTmp = pA->pVNext;
+  pA->pVNext = pB->pVNext;
+  pB->pVNext = pTmp;
+  ppTmp = pA->ppVPrev;
+  pA->ppVPrev = pB->ppVPrev;
+  pB->ppVPrev = ppTmp;
+  zTmp = pA->zSql;
+  pA->zSql = pB->zSql;
+  pB->zSql = zTmp;
+#ifdef SQLITE_ENABLE_NORMALIZE
+  zTmp = pA->zNormSql;
+  pA->zNormSql = pB->zNormSql;
+  pB->zNormSql = zTmp;
+#endif
+  pB->expmask = pA->expmask;
+  pB->prepFlags = pA->prepFlags;
+  memcpy(pB->aCounter, pA->aCounter, sizeof(pB->aCounter));
+  pB->aCounter[SQLITE_STMTSTATUS_REPREPARE]++;
+}
+
+/*
+** Resize the Vdbe.aOp array so that it is at least nOp elements larger
+** than its current size. nOp is guaranteed to be less than or equal
+** to 1024/sizeof(Op).
+**
+** If an out-of-memory error occurs while resizing the array, return
+** SQLITE_NOMEM. In this case Vdbe.aOp and Vdbe.nOpAlloc remain
+** unchanged (this is so that any opcodes already allocated can be
+** correctly deallocated along with the rest of the Vdbe).
+*/
+static int growOpArray(Vdbe *v, int nOp){
+  VdbeOp *pNew;
+  Parse *p = v->pParse;
+
+  /* The SQLITE_TEST_REALLOC_STRESS compile-time option is designed to force
+  ** more frequent reallocs and hence provide more opportunities for
+  ** simulated OOM faults.  SQLITE_TEST_REALLOC_STRESS is generally used
+  ** during testing only.  With SQLITE_TEST_REALLOC_STRESS grow the op array
+  ** by the minimum* amount required until the size reaches 512.  Normal
+  ** operation (without SQLITE_TEST_REALLOC_STRESS) is to double the current
+  ** size of the op array or add 1KB of space, whichever is smaller. */
+#ifdef SQLITE_TEST_REALLOC_STRESS
+  sqlite3_int64 nNew = (v->nOpAlloc>=512 ? 2*(sqlite3_int64)v->nOpAlloc
+                        : (sqlite3_int64)v->nOpAlloc+nOp);
+#else
+  sqlite3_int64 nNew = (v->nOpAlloc ? 2*(sqlite3_int64)v->nOpAlloc
+                        : (sqlite3_int64)(1024/sizeof(Op)));
+  UNUSED_PARAMETER(nOp);
+#endif
+
+  /* Ensure that the size of a VDBE does not grow too large */
+  if( nNew > p->db->aLimit[SQLITE_LIMIT_VDBE_OP] ){
+    sqlite3OomFault(p->db);
+    return SQLITE_NOMEM;
+  }
+
+  assert( nOp<=(int)(1024/sizeof(Op)) );
+  assert( nNew>=(v->nOpAlloc+nOp) );
+  pNew = sqlite3DbRealloc(p->db, v->aOp, nNew*sizeof(Op));
+  if( pNew ){
+    p->szOpAlloc = sqlite3DbMallocSize(p->db, pNew);
+    v->nOpAlloc = p->szOpAlloc/sizeof(Op);
+    v->aOp = pNew;
+  }
+  return (pNew ? SQLITE_OK : SQLITE_NOMEM_BKPT);
+}
+
+#ifdef SQLITE_DEBUG
+/* This routine is just a convenient place to set a breakpoint that will
+** fire after each opcode is inserted and displayed using
+** "PRAGMA vdbe_addoptrace=on".  Parameters "pc" (program counter) and
+** pOp are available to make the breakpoint conditional.
+**
+** Other useful labels for breakpoints include:
+**   test_trace_breakpoint(pc,pOp)
+**   sqlite3CorruptError(lineno)
+**   sqlite3MisuseError(lineno)
+**   sqlite3CantopenError(lineno)
+*/
+static void test_addop_breakpoint(int pc, Op *pOp){
+  static u64 n = 0;
+  (void)pc;
+  (void)pOp;
+  n++;
+  if( n==LARGEST_UINT64 ) abort(); /* so that n is used, preventing a warning */
+}
+#endif
+
+/*
+** Slow paths for sqlite3VdbeAddOp3() and sqlite3VdbeAddOp4Int() for the
+** unusual case when we need to increase the size of the Vdbe.aOp[] array
+** before adding the new opcode.
+*/
+static SQLITE_NOINLINE int growOp3(Vdbe *p, int op, int p1, int p2, int p3){
+  assert( p->nOpAlloc<=p->nOp );
+  if( growOpArray(p, 1) ) return 1;
+  assert( p->nOpAlloc>p->nOp );
+  return sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+}
+static SQLITE_NOINLINE int addOp4IntSlow(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  int p4              /* The P4 operand as an integer */
+){
+  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+  if( p->db->mallocFailed==0 ){
+    VdbeOp *pOp = &p->aOp[addr];
+    pOp->p4type = P4_INT32;
+    pOp->p4.i = p4;
+  }
+  return addr;
+}
+
+
+/*
+** Add a new instruction to the list of instructions current in the
+** VDBE.  Return the address of the new instruction.
+**
+** Parameters:
+**
+**    p               Pointer to the VDBE
+**
+**    op              The opcode for this instruction
+**
+**    p1, p2, p3, p4  Operands
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp0(Vdbe *p, int op){
+  return sqlite3VdbeAddOp3(p, op, 0, 0, 0);
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp1(Vdbe *p, int op, int p1){
+  return sqlite3VdbeAddOp3(p, op, p1, 0, 0);
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp2(Vdbe *p, int op, int p1, int p2){
+  return sqlite3VdbeAddOp3(p, op, p1, p2, 0);
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){
+  int i;
+  VdbeOp *pOp;
+
+  i = p->nOp;
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  assert( op>=0 && op<0xff );
+  if( p->nOpAlloc<=i ){
+    return growOp3(p, op, p1, p2, p3);
+  }
+  assert( p->aOp!=0 );
+  p->nOp++;
+  pOp = &p->aOp[i];
+  assert( pOp!=0 );
+  pOp->opcode = (u8)op;
+  pOp->p5 = 0;
+  pOp->p1 = p1;
+  pOp->p2 = p2;
+  pOp->p3 = p3;
+  pOp->p4.p = 0;
+  pOp->p4type = P4_NOTUSED;
+
+  /* Replicate this logic in sqlite3VdbeAddOp4Int()
+  ** vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv   */
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  pOp->zComment = 0;
+#endif
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
+  pOp->nExec = 0;
+  pOp->nCycle = 0;
+#endif
+#ifdef SQLITE_DEBUG
+  if( p->db->flags & SQLITE_VdbeAddopTrace ){
+    sqlite3VdbePrintOp(0, i, &p->aOp[i]);
+    test_addop_breakpoint(i, &p->aOp[i]);
+  }
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  pOp->iSrcLine = 0;
+#endif
+  /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  ** Replicate in sqlite3VdbeAddOp4Int() */
+
+  return i;
+}
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Int(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  int p4              /* The P4 operand as an integer */
+){
+  int i;
+  VdbeOp *pOp;
+
+  i = p->nOp;
+  if( p->nOpAlloc<=i ){
+    return addOp4IntSlow(p, op, p1, p2, p3, p4);
+  }
+  p->nOp++;
+  pOp = &p->aOp[i];
+  assert( pOp!=0 );
+  pOp->opcode = (u8)op;
+  pOp->p5 = 0;
+  pOp->p1 = p1;
+  pOp->p2 = p2;
+  pOp->p3 = p3;
+  pOp->p4.i = p4;
+  pOp->p4type = P4_INT32;
+
+  /* Replicate this logic in sqlite3VdbeAddOp3()
+  ** vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv   */
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  pOp->zComment = 0;
+#endif
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
+  pOp->nExec = 0;
+  pOp->nCycle = 0;
+#endif
+#ifdef SQLITE_DEBUG
+  if( p->db->flags & SQLITE_VdbeAddopTrace ){
+    sqlite3VdbePrintOp(0, i, &p->aOp[i]);
+    test_addop_breakpoint(i, &p->aOp[i]);
+  }
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+  pOp->iSrcLine = 0;
+#endif
+  /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  ** Replicate in sqlite3VdbeAddOp3() */
+
+  return i;
+}
+
+/* Generate code for an unconditional jump to instruction iDest
+*/
+SQLITE_PRIVATE int sqlite3VdbeGoto(Vdbe *p, int iDest){
+  return sqlite3VdbeAddOp3(p, OP_Goto, 0, iDest, 0);
+}
+
+/* Generate code to cause the string zStr to be loaded into
+** register iDest
+*/
+SQLITE_PRIVATE int sqlite3VdbeLoadString(Vdbe *p, int iDest, const char *zStr){
+  return sqlite3VdbeAddOp4(p, OP_String8, 0, iDest, 0, zStr, 0);
+}
+
+/*
+** Generate code that initializes multiple registers to string or integer
+** constants.  The registers begin with iDest and increase consecutively.
+** One register is initialized for each characgter in zTypes[].  For each
+** "s" character in zTypes[], the register is a string if the argument is
+** not NULL, or OP_Null if the value is a null pointer.  For each "i" character
+** in zTypes[], the register is initialized to an integer.
+**
+** If the input string does not end with "X" then an OP_ResultRow instruction
+** is generated for the values inserted.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMultiLoad(Vdbe *p, int iDest, const char *zTypes, ...){
+  va_list ap;
+  int i;
+  char c;
+  va_start(ap, zTypes);
+  for(i=0; (c = zTypes[i])!=0; i++){
+    if( c=='s' ){
+      const char *z = va_arg(ap, const char*);
+      sqlite3VdbeAddOp4(p, z==0 ? OP_Null : OP_String8, 0, iDest+i, 0, z, 0);
+    }else if( c=='i' ){
+      sqlite3VdbeAddOp2(p, OP_Integer, va_arg(ap, int), iDest+i);
+    }else{
+      goto skip_op_resultrow;
+    }
+  }
+  sqlite3VdbeAddOp2(p, OP_ResultRow, iDest, i);
+skip_op_resultrow:
+  va_end(ap);
+}
+
+/*
+** Add an opcode that includes the p4 value as a pointer.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp4(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  const char *zP4,    /* The P4 operand */
+  int p4type          /* P4 operand type */
+){
+  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
+  sqlite3VdbeChangeP4(p, addr, zP4, p4type);
+  return addr;
+}
+
+/*
+** Add an OP_Function or OP_PureFunc opcode.
+**
+** The eCallCtx argument is information (typically taken from Expr.op2)
+** that describes the calling context of the function.  0 means a general
+** function call.  NC_IsCheck means called by a check constraint,
+** NC_IdxExpr means called as part of an index expression.  NC_PartIdx
+** means in the WHERE clause of a partial index.  NC_GenCol means called
+** while computing a generated column value.  0 is the usual case.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddFunctionCall(
+  Parse *pParse,        /* Parsing context */
+  int p1,               /* Constant argument mask */
+  int p2,               /* First argument register */
+  int p3,               /* Register into which results are written */
+  int nArg,             /* Number of argument */
+  const FuncDef *pFunc, /* The function to be invoked */
+  int eCallCtx          /* Calling context */
+){
+  Vdbe *v = pParse->pVdbe;
+  int nByte;
+  int addr;
+  sqlite3_context *pCtx;
+  assert( v );
+  nByte = sizeof(*pCtx) + (nArg-1)*sizeof(sqlite3_value*);
+  pCtx = sqlite3DbMallocRawNN(pParse->db, nByte);
+  if( pCtx==0 ){
+    assert( pParse->db->mallocFailed );
+    freeEphemeralFunction(pParse->db, (FuncDef*)pFunc);
+    return 0;
+  }
+  pCtx->pOut = 0;
+  pCtx->pFunc = (FuncDef*)pFunc;
+  pCtx->pVdbe = 0;
+  pCtx->isError = 0;
+  pCtx->argc = nArg;
+  pCtx->iOp = sqlite3VdbeCurrentAddr(v);
+  addr = sqlite3VdbeAddOp4(v, eCallCtx ? OP_PureFunc : OP_Function,
+                           p1, p2, p3, (char*)pCtx, P4_FUNCCTX);
+  sqlite3VdbeChangeP5(v, eCallCtx & NC_SelfRef);
+  sqlite3MayAbort(pParse);
+  return addr;
+}
+
+/*
+** Add an opcode that includes the p4 value with a P4_INT64 or
+** P4_REAL type.
+*/
+SQLITE_PRIVATE int sqlite3VdbeAddOp4Dup8(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  const u8 *zP4,      /* The P4 operand */
+  int p4type          /* P4 operand type */
+){
+  char *p4copy = sqlite3DbMallocRawNN(sqlite3VdbeDb(p), 8);
+  if( p4copy ) memcpy(p4copy, zP4, 8);
+  return sqlite3VdbeAddOp4(p, op, p1, p2, p3, p4copy, p4type);
+}
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Return the address of the current EXPLAIN QUERY PLAN baseline.
+** 0 means "none".
+*/
+SQLITE_PRIVATE int sqlite3VdbeExplainParent(Parse *pParse){
+  VdbeOp *pOp;
+  if( pParse->addrExplain==0 ) return 0;
+  pOp = sqlite3VdbeGetOp(pParse->pVdbe, pParse->addrExplain);
+  return pOp->p2;
+}
+
+/*
+** Set a debugger breakpoint on the following routine in order to
+** monitor the EXPLAIN QUERY PLAN code generation.
+*/
+#if defined(SQLITE_DEBUG)
+SQLITE_PRIVATE void sqlite3ExplainBreakpoint(const char *z1, const char *z2){
+  (void)z1;
+  (void)z2;
+}
+#endif
+
+/*
+** Add a new OP_Explain opcode.
+**
+** If the bPush flag is true, then make this opcode the parent for
+** subsequent Explains until sqlite3VdbeExplainPop() is called.
+*/
+SQLITE_PRIVATE int sqlite3VdbeExplain(Parse *pParse, u8 bPush, const char *zFmt, ...){
+  int addr = 0;
+#if !defined(SQLITE_DEBUG)
+  /* Always include the OP_Explain opcodes if SQLITE_DEBUG is defined.
+  ** But omit them (for performance) during production builds */
+  if( pParse->explain==2 || IS_STMT_SCANSTATUS(pParse->db) )
+#endif
+  {
+    char *zMsg;
+    Vdbe *v;
+    va_list ap;
+    int iThis;
+    va_start(ap, zFmt);
+    zMsg = sqlite3VMPrintf(pParse->db, zFmt, ap);
+    va_end(ap);
+    v = pParse->pVdbe;
+    iThis = v->nOp;
+    addr = sqlite3VdbeAddOp4(v, OP_Explain, iThis, pParse->addrExplain, 0,
+                      zMsg, P4_DYNAMIC);
+    sqlite3ExplainBreakpoint(bPush?"PUSH":"", sqlite3VdbeGetLastOp(v)->p4.z);
+    if( bPush){
+      pParse->addrExplain = iThis;
+    }
+    sqlite3VdbeScanStatus(v, iThis, -1, -1, 0, 0);
+  }
+  return addr;
+}
+
+/*
+** Pop the EXPLAIN QUERY PLAN stack one level.
+*/
+SQLITE_PRIVATE void sqlite3VdbeExplainPop(Parse *pParse){
+  sqlite3ExplainBreakpoint("POP", 0);
+  pParse->addrExplain = sqlite3VdbeExplainParent(pParse);
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+
+/*
+** Add an OP_ParseSchema opcode.  This routine is broken out from
+** sqlite3VdbeAddOp4() since it needs to also needs to mark all btrees
+** as having been used.
+**
+** The zWhere string must have been obtained from sqlite3_malloc().
+** This routine will take ownership of the allocated memory.
+*/
+SQLITE_PRIVATE void sqlite3VdbeAddParseSchemaOp(Vdbe *p, int iDb, char *zWhere, u16 p5){
+  int j;
+  sqlite3VdbeAddOp4(p, OP_ParseSchema, iDb, 0, 0, zWhere, P4_DYNAMIC);
+  sqlite3VdbeChangeP5(p, p5);
+  for(j=0; j<p->db->nDb; j++) sqlite3VdbeUsesBtree(p, j);
+  sqlite3MayAbort(p->pParse);
+}
+
+/* Insert the end of a co-routine
+*/
+SQLITE_PRIVATE void sqlite3VdbeEndCoroutine(Vdbe *v, int regYield){
+  sqlite3VdbeAddOp1(v, OP_EndCoroutine, regYield);
+
+  /* Clear the temporary register cache, thereby ensuring that each
+  ** co-routine has its own independent set of registers, because co-routines
+  ** might expect their registers to be preserved across an OP_Yield, and
+  ** that could cause problems if two or more co-routines are using the same
+  ** temporary register.
+  */
+  v->pParse->nTempReg = 0;
+  v->pParse->nRangeReg = 0;
+}
+
+/*
+** Create a new symbolic label for an instruction that has yet to be
+** coded.  The symbolic label is really just a negative number.  The
+** label can be used as the P2 value of an operation.  Later, when
+** the label is resolved to a specific address, the VDBE will scan
+** through its operation list and change all values of P2 which match
+** the label into the resolved address.
+**
+** The VDBE knows that a P2 value is a label because labels are
+** always negative and P2 values are suppose to be non-negative.
+** Hence, a negative P2 value is a label that has yet to be resolved.
+** (Later:) This is only true for opcodes that have the OPFLG_JUMP
+** property.
+**
+** Variable usage notes:
+**
+**     Parse.aLabel[x]     Stores the address that the x-th label resolves
+**                         into.  For testing (SQLITE_DEBUG), unresolved
+**                         labels stores -1, but that is not required.
+**     Parse.nLabelAlloc   Number of slots allocated to Parse.aLabel[]
+**     Parse.nLabel        The *negative* of the number of labels that have
+**                         been issued.  The negative is stored because
+**                         that gives a performance improvement over storing
+**                         the equivalent positive value.
+*/
+SQLITE_PRIVATE int sqlite3VdbeMakeLabel(Parse *pParse){
+  return --pParse->nLabel;
+}
+
+/*
+** Resolve label "x" to be the address of the next instruction to
+** be inserted.  The parameter "x" must have been obtained from
+** a prior call to sqlite3VdbeMakeLabel().
+*/
+static SQLITE_NOINLINE void resizeResolveLabel(Parse *p, Vdbe *v, int j){
+  int nNewSize = 10 - p->nLabel;
+  p->aLabel = sqlite3DbReallocOrFree(p->db, p->aLabel,
+                     nNewSize*sizeof(p->aLabel[0]));
+  if( p->aLabel==0 ){
+    p->nLabelAlloc = 0;
+  }else{
+#ifdef SQLITE_DEBUG
+    int i;
+    for(i=p->nLabelAlloc; i<nNewSize; i++) p->aLabel[i] = -1;
+#endif
+    if( nNewSize>=100 && (nNewSize/100)>(p->nLabelAlloc/100) ){
+      sqlite3ProgressCheck(p);
+    }
+    p->nLabelAlloc = nNewSize;
+    p->aLabel[j] = v->nOp;
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeResolveLabel(Vdbe *v, int x){
+  Parse *p = v->pParse;
+  int j = ADDR(x);
+  assert( v->eVdbeState==VDBE_INIT_STATE );
+  assert( j<-p->nLabel );
+  assert( j>=0 );
+#ifdef SQLITE_DEBUG
+  if( p->db->flags & SQLITE_VdbeAddopTrace ){
+    printf("RESOLVE LABEL %d to %d\n", x, v->nOp);
+  }
+#endif
+  if( p->nLabelAlloc + p->nLabel < 0 ){
+    resizeResolveLabel(p,v,j);
+  }else{
+    assert( p->aLabel[j]==(-1) ); /* Labels may only be resolved once */
+    p->aLabel[j] = v->nOp;
+  }
+}
+
+/*
+** Mark the VDBE as one that can only be run one time.
+*/
+SQLITE_PRIVATE void sqlite3VdbeRunOnlyOnce(Vdbe *p){
+  sqlite3VdbeAddOp2(p, OP_Expire, 1, 1);
+}
+
+/*
+** Mark the VDBE as one that can be run multiple times.
+*/
+SQLITE_PRIVATE void sqlite3VdbeReusable(Vdbe *p){
+  int i;
+  for(i=1; ALWAYS(i<p->nOp); i++){
+    if( ALWAYS(p->aOp[i].opcode==OP_Expire) ){
+      p->aOp[1].opcode = OP_Noop;
+      break;
+    }
+  }
+}
+
+#ifdef SQLITE_DEBUG /* sqlite3AssertMayAbort() logic */
+
+/*
+** The following type and function are used to iterate through all opcodes
+** in a Vdbe main program and each of the sub-programs (triggers) it may
+** invoke directly or indirectly. It should be used as follows:
+**
+**   Op *pOp;
+**   VdbeOpIter sIter;
+**
+**   memset(&sIter, 0, sizeof(sIter));
+**   sIter.v = v;                            // v is of type Vdbe*
+**   while( (pOp = opIterNext(&sIter)) ){
+**     // Do something with pOp
+**   }
+**   sqlite3DbFree(v->db, sIter.apSub);
+**
+*/
+typedef struct VdbeOpIter VdbeOpIter;
+struct VdbeOpIter {
+  Vdbe *v;                   /* Vdbe to iterate through the opcodes of */
+  SubProgram **apSub;        /* Array of subprograms */
+  int nSub;                  /* Number of entries in apSub */
+  int iAddr;                 /* Address of next instruction to return */
+  int iSub;                  /* 0 = main program, 1 = first sub-program etc. */
+};
+static Op *opIterNext(VdbeOpIter *p){
+  Vdbe *v = p->v;
+  Op *pRet = 0;
+  Op *aOp;
+  int nOp;
+
+  if( p->iSub<=p->nSub ){
+
+    if( p->iSub==0 ){
+      aOp = v->aOp;
+      nOp = v->nOp;
+    }else{
+      aOp = p->apSub[p->iSub-1]->aOp;
+      nOp = p->apSub[p->iSub-1]->nOp;
+    }
+    assert( p->iAddr<nOp );
+
+    pRet = &aOp[p->iAddr];
+    p->iAddr++;
+    if( p->iAddr==nOp ){
+      p->iSub++;
+      p->iAddr = 0;
+    }
+
+    if( pRet->p4type==P4_SUBPROGRAM ){
+      int nByte = (p->nSub+1)*sizeof(SubProgram*);
+      int j;
+      for(j=0; j<p->nSub; j++){
+        if( p->apSub[j]==pRet->p4.pProgram ) break;
+      }
+      if( j==p->nSub ){
+        p->apSub = sqlite3DbReallocOrFree(v->db, p->apSub, nByte);
+        if( !p->apSub ){
+          pRet = 0;
+        }else{
+          p->apSub[p->nSub++] = pRet->p4.pProgram;
+        }
+      }
+    }
+  }
+
+  return pRet;
+}
+
+/*
+** Check if the program stored in the VM associated with pParse may
+** throw an ABORT exception (causing the statement, but not entire transaction
+** to be rolled back). This condition is true if the main program or any
+** sub-programs contains any of the following:
+**
+**   *  OP_Halt with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
+**   *  OP_HaltIfNull with P1=SQLITE_CONSTRAINT and P2=OE_Abort.
+**   *  OP_Destroy
+**   *  OP_VUpdate
+**   *  OP_VCreate
+**   *  OP_VRename
+**   *  OP_FkCounter with P2==0 (immediate foreign key constraint)
+**   *  OP_CreateBtree/BTREE_INTKEY and OP_InitCoroutine
+**      (for CREATE TABLE AS SELECT ...)
+**
+** Then check that the value of Parse.mayAbort is true if an
+** ABORT may be thrown, or false otherwise. Return true if it does
+** match, or false otherwise. This function is intended to be used as
+** part of an assert statement in the compiler. Similar to:
+**
+**   assert( sqlite3VdbeAssertMayAbort(pParse->pVdbe, pParse->mayAbort) );
+*/
+SQLITE_PRIVATE int sqlite3VdbeAssertMayAbort(Vdbe *v, int mayAbort){
+  int hasAbort = 0;
+  int hasFkCounter = 0;
+  int hasCreateTable = 0;
+  int hasCreateIndex = 0;
+  int hasInitCoroutine = 0;
+  Op *pOp;
+  VdbeOpIter sIter;
+
+  if( v==0 ) return 0;
+  memset(&sIter, 0, sizeof(sIter));
+  sIter.v = v;
+
+  while( (pOp = opIterNext(&sIter))!=0 ){
+    int opcode = pOp->opcode;
+    if( opcode==OP_Destroy || opcode==OP_VUpdate || opcode==OP_VRename
+     || opcode==OP_VDestroy
+     || opcode==OP_VCreate
+     || opcode==OP_ParseSchema
+     || opcode==OP_Function || opcode==OP_PureFunc
+     || ((opcode==OP_Halt || opcode==OP_HaltIfNull)
+      && ((pOp->p1)!=SQLITE_OK && pOp->p2==OE_Abort))
+    ){
+      hasAbort = 1;
+      break;
+    }
+    if( opcode==OP_CreateBtree && pOp->p3==BTREE_INTKEY ) hasCreateTable = 1;
+    if( mayAbort ){
+      /* hasCreateIndex may also be set for some DELETE statements that use
+      ** OP_Clear. So this routine may end up returning true in the case
+      ** where a "DELETE FROM tbl" has a statement-journal but does not
+      ** require one. This is not so bad - it is an inefficiency, not a bug. */
+      if( opcode==OP_CreateBtree && pOp->p3==BTREE_BLOBKEY ) hasCreateIndex = 1;
+      if( opcode==OP_Clear ) hasCreateIndex = 1;
+    }
+    if( opcode==OP_InitCoroutine ) hasInitCoroutine = 1;
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+    if( opcode==OP_FkCounter && pOp->p1==0 && pOp->p2==1 ){
+      hasFkCounter = 1;
+    }
+#endif
+  }
+  sqlite3DbFree(v->db, sIter.apSub);
+
+  /* Return true if hasAbort==mayAbort. Or if a malloc failure occurred.
+  ** If malloc failed, then the while() loop above may not have iterated
+  ** through all opcodes and hasAbort may be set incorrectly. Return
+  ** true for this case to prevent the assert() in the callers frame
+  ** from failing.  */
+  return ( v->db->mallocFailed || hasAbort==mayAbort || hasFkCounter
+        || (hasCreateTable && hasInitCoroutine) || hasCreateIndex
+  );
+}
+#endif /* SQLITE_DEBUG - the sqlite3AssertMayAbort() function */
+
+#ifdef SQLITE_DEBUG
+/*
+** Increment the nWrite counter in the VDBE if the cursor is not an
+** ephemeral cursor, or if the cursor argument is NULL.
+*/
+SQLITE_PRIVATE void sqlite3VdbeIncrWriteCounter(Vdbe *p, VdbeCursor *pC){
+  if( pC==0
+   || (pC->eCurType!=CURTYPE_SORTER
+       && pC->eCurType!=CURTYPE_PSEUDO
+       && !pC->isEphemeral)
+  ){
+    p->nWrite++;
+  }
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Assert if an Abort at this point in time might result in a corrupt
+** database.
+*/
+SQLITE_PRIVATE void sqlite3VdbeAssertAbortable(Vdbe *p){
+  assert( p->nWrite==0 || p->usesStmtJournal );
+}
+#endif
+
+/*
+** This routine is called after all opcodes have been inserted.  It loops
+** through all the opcodes and fixes up some details.
+**
+** (1) For each jump instruction with a negative P2 value (a label)
+**     resolve the P2 value to an actual address.
+**
+** (2) Compute the maximum number of arguments used by any SQL function
+**     and store that value in *pMaxFuncArgs.
+**
+** (3) Update the Vdbe.readOnly and Vdbe.bIsReader flags to accurately
+**     indicate what the prepared statement actually does.
+**
+** (4) (discontinued)
+**
+** (5) Reclaim the memory allocated for storing labels.
+**
+** This routine will only function correctly if the mkopcodeh.tcl generator
+** script numbers the opcodes correctly.  Changes to this routine must be
+** coordinated with changes to mkopcodeh.tcl.
+*/
+static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
+  int nMaxArgs = *pMaxFuncArgs;
+  Op *pOp;
+  Parse *pParse = p->pParse;
+  int *aLabel = pParse->aLabel;
+
+  assert( pParse->db->mallocFailed==0 ); /* tag-20230419-1 */
+  p->readOnly = 1;
+  p->bIsReader = 0;
+  pOp = &p->aOp[p->nOp-1];
+  assert( p->aOp[0].opcode==OP_Init );
+  while( 1 /* Loop terminates when it reaches the OP_Init opcode */ ){
+    /* Only JUMP opcodes and the short list of special opcodes in the switch
+    ** below need to be considered.  The mkopcodeh.tcl generator script groups
+    ** all these opcodes together near the front of the opcode list.  Skip
+    ** any opcode that does not need processing by virtual of the fact that
+    ** it is larger than SQLITE_MX_JUMP_OPCODE, as a performance optimization.
+    */
+    if( pOp->opcode<=SQLITE_MX_JUMP_OPCODE ){
+      /* NOTE: Be sure to update mkopcodeh.tcl when adding or removing
+      ** cases from this switch! */
+      switch( pOp->opcode ){
+        case OP_Transaction: {
+          if( pOp->p2!=0 ) p->readOnly = 0;
+          /* no break */ deliberate_fall_through
+        }
+        case OP_AutoCommit:
+        case OP_Savepoint: {
+          p->bIsReader = 1;
+          break;
+        }
+#ifndef SQLITE_OMIT_WAL
+        case OP_Checkpoint:
+#endif
+        case OP_Vacuum:
+        case OP_JournalMode: {
+          p->readOnly = 0;
+          p->bIsReader = 1;
+          break;
+        }
+        case OP_Init: {
+          assert( pOp->p2>=0 );
+          goto resolve_p2_values_loop_exit;
+        }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+        case OP_VUpdate: {
+          if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
+          break;
+        }
+        case OP_VFilter: {
+          int n;
+          assert( (pOp - p->aOp) >= 3 );
+          assert( pOp[-1].opcode==OP_Integer );
+          n = pOp[-1].p1;
+          if( n>nMaxArgs ) nMaxArgs = n;
+          /* Fall through into the default case */
+          /* no break */ deliberate_fall_through
+        }
+#endif
+        default: {
+          if( pOp->p2<0 ){
+            /* The mkopcodeh.tcl script has so arranged things that the only
+            ** non-jump opcodes less than SQLITE_MX_JUMP_CODE are guaranteed to
+            ** have non-negative values for P2. */
+            assert( (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_JUMP)!=0 );
+            assert( ADDR(pOp->p2)<-pParse->nLabel );
+            assert( aLabel!=0 );  /* True because of tag-20230419-1 */
+            pOp->p2 = aLabel[ADDR(pOp->p2)];
+          }
+
+          /* OPFLG_JUMP opcodes never have P2==0, though OPFLG_JUMP0 opcodes
+          ** might */
+          assert( pOp->p2>0
+                  || (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_JUMP0)!=0 );
+
+          /* Jumps never go off the end of the bytecode array */
+          assert( pOp->p2<p->nOp
+                  || (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_JUMP)==0 );
+          break;
+        }
+      }
+      /* The mkopcodeh.tcl script has so arranged things that the only
+      ** non-jump opcodes less than SQLITE_MX_JUMP_CODE are guaranteed to
+      ** have non-negative values for P2. */
+      assert( (sqlite3OpcodeProperty[pOp->opcode]&OPFLG_JUMP)==0 || pOp->p2>=0);
+    }
+    assert( pOp>p->aOp );
+    pOp--;
+  }
+resolve_p2_values_loop_exit:
+  if( aLabel ){
+    sqlite3DbNNFreeNN(p->db, pParse->aLabel);
+    pParse->aLabel = 0;
+  }
+  pParse->nLabel = 0;
+  *pMaxFuncArgs = nMaxArgs;
+  assert( p->bIsReader!=0 || DbMaskAllZero(p->btreeMask) );
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Check to see if a subroutine contains a jump to a location outside of
+** the subroutine.  If a jump outside the subroutine is detected, add code
+** that will cause the program to halt with an error message.
+**
+** The subroutine consists of opcodes between iFirst and iLast.  Jumps to
+** locations within the subroutine are acceptable.  iRetReg is a register
+** that contains the return address.  Jumps to outside the range of iFirst
+** through iLast are also acceptable as long as the jump destination is
+** an OP_Return to iReturnAddr.
+**
+** A jump to an unresolved label means that the jump destination will be
+** beyond the current address.  That is normally a jump to an early
+** termination and is consider acceptable.
+**
+** This routine only runs during debug builds.  The purpose is (of course)
+** to detect invalid escapes out of a subroutine.  The OP_Halt opcode
+** is generated rather than an assert() or other error, so that ".eqp full"
+** will still work to show the original bytecode, to aid in debugging.
+*/
+SQLITE_PRIVATE void sqlite3VdbeNoJumpsOutsideSubrtn(
+  Vdbe *v,          /* The byte-code program under construction */
+  int iFirst,       /* First opcode of the subroutine */
+  int iLast,        /* Last opcode of the subroutine */
+  int iRetReg       /* Subroutine return address register */
+){
+  VdbeOp *pOp;
+  Parse *pParse;
+  int i;
+  sqlite3_str *pErr = 0;
+  assert( v!=0 );
+  pParse = v->pParse;
+  assert( pParse!=0 );
+  if( pParse->nErr ) return;
+  assert( iLast>=iFirst );
+  assert( iLast<v->nOp );
+  pOp = &v->aOp[iFirst];
+  for(i=iFirst; i<=iLast; i++, pOp++){
+    if( (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_JUMP)!=0 ){
+      int iDest = pOp->p2;   /* Jump destination */
+      if( iDest==0 ) continue;
+      if( pOp->opcode==OP_Gosub ) continue;
+      if( pOp->p3==20230325 && pOp->opcode==OP_NotNull ){
+        /* This is a deliberately taken illegal branch.  tag-20230325-2 */
+        continue;
+      }
+      if( iDest<0 ){
+        int j = ADDR(iDest);
+        assert( j>=0 );
+        if( j>=-pParse->nLabel || pParse->aLabel[j]<0 ){
+          continue;
+        }
+        iDest = pParse->aLabel[j];
+      }
+      if( iDest<iFirst || iDest>iLast ){
+        int j = iDest;
+        for(; j<v->nOp; j++){
+          VdbeOp *pX = &v->aOp[j];
+          if( pX->opcode==OP_Return ){
+            if( pX->p1==iRetReg ) break;
+            continue;
+          }
+          if( pX->opcode==OP_Noop ) continue;
+          if( pX->opcode==OP_Explain ) continue;
+          if( pErr==0 ){
+            pErr = sqlite3_str_new(0);
+          }else{
+            sqlite3_str_appendchar(pErr, 1, '\n');
+          }
+          sqlite3_str_appendf(pErr,
+              "Opcode at %d jumps to %d which is outside the "
+              "subroutine at %d..%d",
+              i, iDest, iFirst, iLast);
+          break;
+        }
+      }
+    }
+  }
+  if( pErr ){
+    char *zErr = sqlite3_str_finish(pErr);
+    sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_INTERNAL, OE_Abort, 0, zErr, 0);
+    sqlite3_free(zErr);
+    sqlite3MayAbort(pParse);
+  }
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** Return the address of the next instruction to be inserted.
+*/
+SQLITE_PRIVATE int sqlite3VdbeCurrentAddr(Vdbe *p){
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  return p->nOp;
+}
+
+/*
+** Verify that at least N opcode slots are available in p without
+** having to malloc for more space (except when compiled using
+** SQLITE_TEST_REALLOC_STRESS).  This interface is used during testing
+** to verify that certain calls to sqlite3VdbeAddOpList() can never
+** fail due to a OOM fault and hence that the return value from
+** sqlite3VdbeAddOpList() will always be non-NULL.
+*/
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_TEST_REALLOC_STRESS)
+SQLITE_PRIVATE void sqlite3VdbeVerifyNoMallocRequired(Vdbe *p, int N){
+  assert( p->nOp + N <= p->nOpAlloc );
+}
+#endif
+
+/*
+** Verify that the VM passed as the only argument does not contain
+** an OP_ResultRow opcode. Fail an assert() if it does. This is used
+** by code in pragma.c to ensure that the implementation of certain
+** pragmas comports with the flags specified in the mkpragmatab.tcl
+** script.
+*/
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_TEST_REALLOC_STRESS)
+SQLITE_PRIVATE void sqlite3VdbeVerifyNoResultRow(Vdbe *p){
+  int i;
+  for(i=0; i<p->nOp; i++){
+    assert( p->aOp[i].opcode!=OP_ResultRow );
+  }
+}
+#endif
+
+/*
+** Generate code (a single OP_Abortable opcode) that will
+** verify that the VDBE program can safely call Abort in the current
+** context.
+*/
+#if defined(SQLITE_DEBUG)
+SQLITE_PRIVATE void sqlite3VdbeVerifyAbortable(Vdbe *p, int onError){
+  if( onError==OE_Abort ) sqlite3VdbeAddOp0(p, OP_Abortable);
+}
+#endif
+
+/*
+** This function returns a pointer to the array of opcodes associated with
+** the Vdbe passed as the first argument. It is the callers responsibility
+** to arrange for the returned array to be eventually freed using the
+** vdbeFreeOpArray() function.
+**
+** Before returning, *pnOp is set to the number of entries in the returned
+** array. Also, *pnMaxArg is set to the larger of its current value and
+** the number of entries in the Vdbe.apArg[] array required to execute the
+** returned program.
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeTakeOpArray(Vdbe *p, int *pnOp, int *pnMaxArg){
+  VdbeOp *aOp = p->aOp;
+  assert( aOp && !p->db->mallocFailed );
+
+  /* Check that sqlite3VdbeUsesBtree() was not called on this VM */
+  assert( DbMaskAllZero(p->btreeMask) );
+
+  resolveP2Values(p, pnMaxArg);
+  *pnOp = p->nOp;
+  p->aOp = 0;
+  return aOp;
+}
+
+/*
+** Add a whole list of operations to the operation stack.  Return a
+** pointer to the first operation inserted.
+**
+** Non-zero P2 arguments to jump instructions are automatically adjusted
+** so that the jump target is relative to the first operation inserted.
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeAddOpList(
+  Vdbe *p,                     /* Add opcodes to the prepared statement */
+  int nOp,                     /* Number of opcodes to add */
+  VdbeOpList const *aOp,       /* The opcodes to be added */
+  int iLineno                  /* Source-file line number of first opcode */
+){
+  int i;
+  VdbeOp *pOut, *pFirst;
+  assert( nOp>0 );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  if( p->nOp + nOp > p->nOpAlloc && growOpArray(p, nOp) ){
+    return 0;
+  }
+  pFirst = pOut = &p->aOp[p->nOp];
+  for(i=0; i<nOp; i++, aOp++, pOut++){
+    pOut->opcode = aOp->opcode;
+    pOut->p1 = aOp->p1;
+    pOut->p2 = aOp->p2;
+    assert( aOp->p2>=0 );
+    if( (sqlite3OpcodeProperty[aOp->opcode] & OPFLG_JUMP)!=0 && aOp->p2>0 ){
+      pOut->p2 += p->nOp;
+    }
+    pOut->p3 = aOp->p3;
+    pOut->p4type = P4_NOTUSED;
+    pOut->p4.p = 0;
+    pOut->p5 = 0;
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+    pOut->zComment = 0;
+#endif
+#ifdef SQLITE_VDBE_COVERAGE
+    pOut->iSrcLine = iLineno+i;
+#else
+    (void)iLineno;
+#endif
+#ifdef SQLITE_DEBUG
+    if( p->db->flags & SQLITE_VdbeAddopTrace ){
+      sqlite3VdbePrintOp(0, i+p->nOp, &p->aOp[i+p->nOp]);
+    }
+#endif
+  }
+  p->nOp += nOp;
+  return pFirst;
+}
+
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+/*
+** Add an entry to the array of counters managed by sqlite3_stmt_scanstatus().
+*/
+SQLITE_PRIVATE void sqlite3VdbeScanStatus(
+  Vdbe *p,                        /* VM to add scanstatus() to */
+  int addrExplain,                /* Address of OP_Explain (or 0) */
+  int addrLoop,                   /* Address of loop counter */
+  int addrVisit,                  /* Address of rows visited counter */
+  LogEst nEst,                    /* Estimated number of output rows */
+  const char *zName               /* Name of table or index being scanned */
+){
+  if( IS_STMT_SCANSTATUS(p->db) ){
+    sqlite3_int64 nByte = (p->nScan+1) * sizeof(ScanStatus);
+    ScanStatus *aNew;
+    aNew = (ScanStatus*)sqlite3DbRealloc(p->db, p->aScan, nByte);
+    if( aNew ){
+      ScanStatus *pNew = &aNew[p->nScan++];
+      memset(pNew, 0, sizeof(ScanStatus));
+      pNew->addrExplain = addrExplain;
+      pNew->addrLoop = addrLoop;
+      pNew->addrVisit = addrVisit;
+      pNew->nEst = nEst;
+      pNew->zName = sqlite3DbStrDup(p->db, zName);
+      p->aScan = aNew;
+    }
+  }
+}
+
+/*
+** Add the range of instructions from addrStart to addrEnd (inclusive) to
+** the set of those corresponding to the sqlite3_stmt_scanstatus() counters
+** associated with the OP_Explain instruction at addrExplain. The
+** sum of the sqlite3Hwtime() values for each of these instructions
+** will be returned for SQLITE_SCANSTAT_NCYCLE requests.
+*/
+SQLITE_PRIVATE void sqlite3VdbeScanStatusRange(
+  Vdbe *p,
+  int addrExplain,
+  int addrStart,
+  int addrEnd
+){
+  if( IS_STMT_SCANSTATUS(p->db) ){
+    ScanStatus *pScan = 0;
+    int ii;
+    for(ii=p->nScan-1; ii>=0; ii--){
+      pScan = &p->aScan[ii];
+      if( pScan->addrExplain==addrExplain ) break;
+      pScan = 0;
+    }
+    if( pScan ){
+      if( addrEnd<0 ) addrEnd = sqlite3VdbeCurrentAddr(p)-1;
+      for(ii=0; ii<ArraySize(pScan->aAddrRange); ii+=2){
+        if( pScan->aAddrRange[ii]==0 ){
+          pScan->aAddrRange[ii] = addrStart;
+          pScan->aAddrRange[ii+1] = addrEnd;
+          break;
+        }
+      }
+    }
+  }
+}
+
+/*
+** Set the addresses for the SQLITE_SCANSTAT_NLOOP and SQLITE_SCANSTAT_NROW
+** counters for the query element associated with the OP_Explain at
+** addrExplain.
+*/
+SQLITE_PRIVATE void sqlite3VdbeScanStatusCounters(
+  Vdbe *p,
+  int addrExplain,
+  int addrLoop,
+  int addrVisit
+){
+  if( IS_STMT_SCANSTATUS(p->db) ){
+    ScanStatus *pScan = 0;
+    int ii;
+    for(ii=p->nScan-1; ii>=0; ii--){
+      pScan = &p->aScan[ii];
+      if( pScan->addrExplain==addrExplain ) break;
+      pScan = 0;
+    }
+    if( pScan ){
+      if( addrLoop>0 ) pScan->addrLoop = addrLoop;
+      if( addrVisit>0 ) pScan->addrVisit = addrVisit;
+    }
+  }
+}
+#endif /* defined(SQLITE_ENABLE_STMT_SCANSTATUS) */
+
+
+/*
+** Change the value of the opcode, or P1, P2, P3, or P5 operands
+** for a specific instruction.
+*/
+SQLITE_PRIVATE void sqlite3VdbeChangeOpcode(Vdbe *p, int addr, u8 iNewOpcode){
+  assert( addr>=0 );
+  sqlite3VdbeGetOp(p,addr)->opcode = iNewOpcode;
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP1(Vdbe *p, int addr, int val){
+  assert( addr>=0 );
+  sqlite3VdbeGetOp(p,addr)->p1 = val;
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP2(Vdbe *p, int addr, int val){
+  assert( addr>=0 || p->db->mallocFailed );
+  sqlite3VdbeGetOp(p,addr)->p2 = val;
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP3(Vdbe *p, int addr, int val){
+  assert( addr>=0 );
+  sqlite3VdbeGetOp(p,addr)->p3 = val;
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP5(Vdbe *p, u16 p5){
+  assert( p->nOp>0 || p->db->mallocFailed );
+  if( p->nOp>0 ) p->aOp[p->nOp-1].p5 = p5;
+}
+
+/*
+** If the previous opcode is an OP_Column that delivers results
+** into register iDest, then add the OPFLAG_TYPEOFARG flag to that
+** opcode.
+*/
+SQLITE_PRIVATE void sqlite3VdbeTypeofColumn(Vdbe *p, int iDest){
+  VdbeOp *pOp = sqlite3VdbeGetLastOp(p);
+  if( pOp->p3==iDest && pOp->opcode==OP_Column ){
+    pOp->p5 |= OPFLAG_TYPEOFARG;
+  }
+}
+
+/*
+** Change the P2 operand of instruction addr so that it points to
+** the address of the next instruction to be coded.
+*/
+SQLITE_PRIVATE void sqlite3VdbeJumpHere(Vdbe *p, int addr){
+  sqlite3VdbeChangeP2(p, addr, p->nOp);
+}
+
+/*
+** Change the P2 operand of the jump instruction at addr so that
+** the jump lands on the next opcode.  Or if the jump instruction was
+** the previous opcode (and is thus a no-op) then simply back up
+** the next instruction counter by one slot so that the jump is
+** overwritten by the next inserted opcode.
+**
+** This routine is an optimization of sqlite3VdbeJumpHere() that
+** strives to omit useless byte-code like this:
+**
+**        7   Once 0 8 0
+**        8   ...
+*/
+SQLITE_PRIVATE void sqlite3VdbeJumpHereOrPopInst(Vdbe *p, int addr){
+  if( addr==p->nOp-1 ){
+    assert( p->aOp[addr].opcode==OP_Once
+         || p->aOp[addr].opcode==OP_If
+         || p->aOp[addr].opcode==OP_FkIfZero );
+    assert( p->aOp[addr].p4type==0 );
+#ifdef SQLITE_VDBE_COVERAGE
+    sqlite3VdbeGetLastOp(p)->iSrcLine = 0;  /* Erase VdbeCoverage() macros */
+#endif
+    p->nOp--;
+  }else{
+    sqlite3VdbeChangeP2(p, addr, p->nOp);
+  }
+}
+
+
+/*
+** If the input FuncDef structure is ephemeral, then free it.  If
+** the FuncDef is not ephemeral, then do nothing.
+*/
+static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef){
+  assert( db!=0 );
+  if( (pDef->funcFlags & SQLITE_FUNC_EPHEM)!=0 ){
+    sqlite3DbNNFreeNN(db, pDef);
+  }
+}
+
+/*
+** Delete a P4 value if necessary.
+*/
+static SQLITE_NOINLINE void freeP4Mem(sqlite3 *db, Mem *p){
+  if( p->szMalloc ) sqlite3DbFree(db, p->zMalloc);
+  sqlite3DbNNFreeNN(db, p);
+}
+static SQLITE_NOINLINE void freeP4FuncCtx(sqlite3 *db, sqlite3_context *p){
+  assert( db!=0 );
+  freeEphemeralFunction(db, p->pFunc);
+  sqlite3DbNNFreeNN(db, p);
+}
+static void freeP4(sqlite3 *db, int p4type, void *p4){
+  assert( db );
+  switch( p4type ){
+    case P4_FUNCCTX: {
+      freeP4FuncCtx(db, (sqlite3_context*)p4);
+      break;
+    }
+    case P4_REAL:
+    case P4_INT64:
+    case P4_DYNAMIC:
+    case P4_INTARRAY: {
+      if( p4 ) sqlite3DbNNFreeNN(db, p4);
+      break;
+    }
+    case P4_KEYINFO: {
+      if( db->pnBytesFreed==0 ) sqlite3KeyInfoUnref((KeyInfo*)p4);
+      break;
+    }
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+    case P4_EXPR: {
+      sqlite3ExprDelete(db, (Expr*)p4);
+      break;
+    }
+#endif
+    case P4_FUNCDEF: {
+      freeEphemeralFunction(db, (FuncDef*)p4);
+      break;
+    }
+    case P4_MEM: {
+      if( db->pnBytesFreed==0 ){
+        sqlite3ValueFree((sqlite3_value*)p4);
+      }else{
+        freeP4Mem(db, (Mem*)p4);
+      }
+      break;
+    }
+    case P4_VTAB : {
+      if( db->pnBytesFreed==0 ) sqlite3VtabUnlock((VTable *)p4);
+      break;
+    }
+    case P4_TABLEREF: {
+      if( db->pnBytesFreed==0 ) sqlite3DeleteTable(db, (Table*)p4);
+      break;
+    }
+    case P4_SUBRTNSIG: {
+      SubrtnSig *pSig = (SubrtnSig*)p4;
+      sqlite3DbFree(db, pSig->zAff);
+      sqlite3DbFree(db, pSig);
+      break;
+    }
+  }
+}
+
+/*
+** Free the space allocated for aOp and any p4 values allocated for the
+** opcodes contained within. If aOp is not NULL it is assumed to contain
+** nOp entries.
+*/
+static void vdbeFreeOpArray(sqlite3 *db, Op *aOp, int nOp){
+  assert( nOp>=0 );
+  assert( db!=0 );
+  if( aOp ){
+    Op *pOp = &aOp[nOp-1];
+    while(1){  /* Exit via break */
+      if( pOp->p4type <= P4_FREE_IF_LE ) freeP4(db, pOp->p4type, pOp->p4.p);
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+      sqlite3DbFree(db, pOp->zComment);
+#endif
+      if( pOp==aOp ) break;
+      pOp--;
+    }
+    sqlite3DbNNFreeNN(db, aOp);
+  }
+}
+
+/*
+** Link the SubProgram object passed as the second argument into the linked
+** list at Vdbe.pSubProgram. This list is used to delete all sub-program
+** objects when the VM is no longer required.
+*/
+SQLITE_PRIVATE void sqlite3VdbeLinkSubProgram(Vdbe *pVdbe, SubProgram *p){
+  p->pNext = pVdbe->pProgram;
+  pVdbe->pProgram = p;
+}
+
+/*
+** Return true if the given Vdbe has any SubPrograms.
+*/
+SQLITE_PRIVATE int sqlite3VdbeHasSubProgram(Vdbe *pVdbe){
+  return pVdbe->pProgram!=0;
+}
+
+/*
+** Change the opcode at addr into OP_Noop
+*/
+SQLITE_PRIVATE int sqlite3VdbeChangeToNoop(Vdbe *p, int addr){
+  VdbeOp *pOp;
+  if( p->db->mallocFailed ) return 0;
+  assert( addr>=0 && addr<p->nOp );
+  pOp = &p->aOp[addr];
+  freeP4(p->db, pOp->p4type, pOp->p4.p);
+  pOp->p4type = P4_NOTUSED;
+  pOp->p4.z = 0;
+  pOp->opcode = OP_Noop;
+  return 1;
+}
+
+/*
+** If the last opcode is "op" and it is not a jump destination,
+** then remove it.  Return true if and only if an opcode was removed.
+*/
+SQLITE_PRIVATE int sqlite3VdbeDeletePriorOpcode(Vdbe *p, u8 op){
+  if( p->nOp>0 && p->aOp[p->nOp-1].opcode==op ){
+    return sqlite3VdbeChangeToNoop(p, p->nOp-1);
+  }else{
+    return 0;
+  }
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Generate an OP_ReleaseReg opcode to indicate that a range of
+** registers, except any identified by mask, are no longer in use.
+*/
+SQLITE_PRIVATE void sqlite3VdbeReleaseRegisters(
+  Parse *pParse,       /* Parsing context */
+  int iFirst,          /* Index of first register to be released */
+  int N,               /* Number of registers to release */
+  u32 mask,            /* Mask of registers to NOT release */
+  int bUndefine        /* If true, mark registers as undefined */
+){
+  if( N==0 || OptimizationDisabled(pParse->db, SQLITE_ReleaseReg) ) return;
+  assert( pParse->pVdbe );
+  assert( iFirst>=1 );
+  assert( iFirst+N-1<=pParse->nMem );
+  if( N<=31 && mask!=0 ){
+    while( N>0 && (mask&1)!=0 ){
+      mask >>= 1;
+      iFirst++;
+      N--;
+    }
+    while( N>0 && N<=32 && (mask & MASKBIT32(N-1))!=0 ){
+      mask &= ~MASKBIT32(N-1);
+      N--;
+    }
+  }
+  if( N>0 ){
+    sqlite3VdbeAddOp3(pParse->pVdbe, OP_ReleaseReg, iFirst, N, *(int*)&mask);
+    if( bUndefine ) sqlite3VdbeChangeP5(pParse->pVdbe, 1);
+  }
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** Change the value of the P4 operand for a specific instruction.
+** This routine is useful when a large program is loaded from a
+** static array using sqlite3VdbeAddOpList but we want to make a
+** few minor changes to the program.
+**
+** If n>=0 then the P4 operand is dynamic, meaning that a copy of
+** the string is made into memory obtained from sqlite3_malloc().
+** A value of n==0 means copy bytes of zP4 up to and including the
+** first null byte.  If n>0 then copy n+1 bytes of zP4.
+**
+** Other values of n (P4_STATIC, P4_COLLSEQ etc.) indicate that zP4 points
+** to a string or structure that is guaranteed to exist for the lifetime of
+** the Vdbe. In these cases we can just copy the pointer.
+**
+** If addr<0 then change P4 on the most recently inserted instruction.
+*/
+static void SQLITE_NOINLINE vdbeChangeP4Full(
+  Vdbe *p,
+  Op *pOp,
+  const char *zP4,
+  int n
+){
+  if( pOp->p4type ){
+    assert( pOp->p4type > P4_FREE_IF_LE );
+    pOp->p4type = 0;
+    pOp->p4.p = 0;
+  }
+  if( n<0 ){
+    sqlite3VdbeChangeP4(p, (int)(pOp - p->aOp), zP4, n);
+  }else{
+    if( n==0 ) n = sqlite3Strlen30(zP4);
+    pOp->p4.z = sqlite3DbStrNDup(p->db, zP4, n);
+    pOp->p4type = P4_DYNAMIC;
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int n){
+  Op *pOp;
+  sqlite3 *db;
+  assert( p!=0 );
+  db = p->db;
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  assert( p->aOp!=0 || db->mallocFailed );
+  if( db->mallocFailed ){
+    if( n!=P4_VTAB ) freeP4(db, n, (void*)*(char**)&zP4);
+    return;
+  }
+  assert( p->nOp>0 );
+  assert( addr<p->nOp );
+  if( addr<0 ){
+    addr = p->nOp - 1;
+  }
+  pOp = &p->aOp[addr];
+  if( n>=0 || pOp->p4type ){
+    vdbeChangeP4Full(p, pOp, zP4, n);
+    return;
+  }
+  if( n==P4_INT32 ){
+    /* Note: this cast is safe, because the origin data point was an int
+    ** that was cast to a (const char *). */
+    pOp->p4.i = SQLITE_PTR_TO_INT(zP4);
+    pOp->p4type = P4_INT32;
+  }else if( zP4!=0 ){
+    assert( n<0 );
+    pOp->p4.p = (void*)zP4;
+    pOp->p4type = (signed char)n;
+    if( n==P4_VTAB ) sqlite3VtabLock((VTable*)zP4);
+  }
+}
+
+/*
+** Change the P4 operand of the most recently coded instruction
+** to the value defined by the arguments.  This is a high-speed
+** version of sqlite3VdbeChangeP4().
+**
+** The P4 operand must not have been previously defined.  And the new
+** P4 must not be P4_INT32.  Use sqlite3VdbeChangeP4() in either of
+** those cases.
+*/
+SQLITE_PRIVATE void sqlite3VdbeAppendP4(Vdbe *p, void *pP4, int n){
+  VdbeOp *pOp;
+  assert( n!=P4_INT32 && n!=P4_VTAB );
+  assert( n<=0 );
+  if( p->db->mallocFailed ){
+    freeP4(p->db, n, pP4);
+  }else{
+    assert( pP4!=0 || n==P4_DYNAMIC );
+    assert( p->nOp>0 );
+    pOp = &p->aOp[p->nOp-1];
+    assert( pOp->p4type==P4_NOTUSED );
+    pOp->p4type = n;
+    pOp->p4.p = pP4;
+  }
+}
+
+/*
+** Set the P4 on the most recently added opcode to the KeyInfo for the
+** index given.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetP4KeyInfo(Parse *pParse, Index *pIdx){
+  Vdbe *v = pParse->pVdbe;
+  KeyInfo *pKeyInfo;
+  assert( v!=0 );
+  assert( pIdx!=0 );
+  pKeyInfo = sqlite3KeyInfoOfIndex(pParse, pIdx);
+  if( pKeyInfo ) sqlite3VdbeAppendP4(v, pKeyInfo, P4_KEYINFO);
+}
+
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+/*
+** Change the comment on the most recently coded instruction.  Or
+** insert a No-op and add the comment to that new instruction.  This
+** makes the code easier to read during debugging.  None of this happens
+** in a production build.
+*/
+static void vdbeVComment(Vdbe *p, const char *zFormat, va_list ap){
+  assert( p->nOp>0 || p->aOp==0 );
+  assert( p->aOp==0 || p->aOp[p->nOp-1].zComment==0 || p->pParse->nErr>0 );
+  if( p->nOp ){
+    assert( p->aOp );
+    sqlite3DbFree(p->db, p->aOp[p->nOp-1].zComment);
+    p->aOp[p->nOp-1].zComment = sqlite3VMPrintf(p->db, zFormat, ap);
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
+  va_list ap;
+  if( p ){
+    va_start(ap, zFormat);
+    vdbeVComment(p, zFormat, ap);
+    va_end(ap);
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeNoopComment(Vdbe *p, const char *zFormat, ...){
+  va_list ap;
+  if( p ){
+    sqlite3VdbeAddOp0(p, OP_Noop);
+    va_start(ap, zFormat);
+    vdbeVComment(p, zFormat, ap);
+    va_end(ap);
+  }
+}
+#endif  /* NDEBUG */
+
+#ifdef SQLITE_VDBE_COVERAGE
+/*
+** Set the value if the iSrcLine field for the previously coded instruction.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetLineNumber(Vdbe *v, int iLine){
+  sqlite3VdbeGetLastOp(v)->iSrcLine = iLine;
+}
+#endif /* SQLITE_VDBE_COVERAGE */
+
+/*
+** Return the opcode for a given address.  The address must be non-negative.
+** See sqlite3VdbeGetLastOp() to get the most recently added opcode.
+**
+** If a memory allocation error has occurred prior to the calling of this
+** routine, then a pointer to a dummy VdbeOp will be returned.  That opcode
+** is readable but not writable, though it is cast to a writable value.
+** The return of a dummy opcode allows the call to continue functioning
+** after an OOM fault without having to check to see if the return from
+** this routine is a valid pointer.  But because the dummy.opcode is 0,
+** dummy will never be written to.  This is verified by code inspection and
+** by running with Valgrind.
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
+  /* C89 specifies that the constant "dummy" will be initialized to all
+  ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
+  static VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
+  if( p->db->mallocFailed ){
+    return (VdbeOp*)&dummy;
+  }else{
+    return &p->aOp[addr];
+  }
+}
+
+/* Return the most recently added opcode
+*/
+SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetLastOp(Vdbe *p){
+  return sqlite3VdbeGetOp(p, p->nOp - 1);
+}
+
+#if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS)
+/*
+** Return an integer value for one of the parameters to the opcode pOp
+** determined by character c.
+*/
+static int translateP(char c, const Op *pOp){
+  if( c=='1' ) return pOp->p1;
+  if( c=='2' ) return pOp->p2;
+  if( c=='3' ) return pOp->p3;
+  if( c=='4' ) return pOp->p4.i;
+  return pOp->p5;
+}
+
+/*
+** Compute a string for the "comment" field of a VDBE opcode listing.
+**
+** The Synopsis: field in comments in the vdbe.c source file gets converted
+** to an extra string that is appended to the sqlite3OpcodeName().  In the
+** absence of other comments, this synopsis becomes the comment on the opcode.
+** Some translation occurs:
+**
+**       "PX"      ->  "r[X]"
+**       "PX@PY"   ->  "r[X..X+Y-1]"  or "r[x]" if y is 0 or 1
+**       "PX@PY+1" ->  "r[X..X+Y]"    or "r[x]" if y is 0
+**       "PY..PY"  ->  "r[X..Y]"      or "r[x]" if y<=x
+*/
+SQLITE_PRIVATE char *sqlite3VdbeDisplayComment(
+  sqlite3 *db,       /* Optional - Oom error reporting only */
+  const Op *pOp,     /* The opcode to be commented */
+  const char *zP4    /* Previously obtained value for P4 */
+){
+  const char *zOpName;
+  const char *zSynopsis;
+  int nOpName;
+  int ii;
+  char zAlt[50];
+  StrAccum x;
+
+  sqlite3StrAccumInit(&x, 0, 0, 0, SQLITE_MAX_LENGTH);
+  zOpName = sqlite3OpcodeName(pOp->opcode);
+  nOpName = sqlite3Strlen30(zOpName);
+  if( zOpName[nOpName+1] ){
+    int seenCom = 0;
+    char c;
+    zSynopsis = zOpName + nOpName + 1;
+    if( strncmp(zSynopsis,"IF ",3)==0 ){
+      sqlite3_snprintf(sizeof(zAlt), zAlt, "if %s goto P2", zSynopsis+3);
+      zSynopsis = zAlt;
+    }
+    for(ii=0; (c = zSynopsis[ii])!=0; ii++){
+      if( c=='P' ){
+        c = zSynopsis[++ii];
+        if( c=='4' ){
+          sqlite3_str_appendall(&x, zP4);
+        }else if( c=='X' ){
+          if( pOp->zComment && pOp->zComment[0] ){
+            sqlite3_str_appendall(&x, pOp->zComment);
+            seenCom = 1;
+            break;
+          }
+        }else{
+          int v1 = translateP(c, pOp);
+          int v2;
+          if( strncmp(zSynopsis+ii+1, "@P", 2)==0 ){
+            ii += 3;
+            v2 = translateP(zSynopsis[ii], pOp);
+            if( strncmp(zSynopsis+ii+1,"+1",2)==0 ){
+              ii += 2;
+              v2++;
+            }
+            if( v2<2 ){
+              sqlite3_str_appendf(&x, "%d", v1);
+            }else{
+              sqlite3_str_appendf(&x, "%d..%d", v1, v1+v2-1);
+            }
+          }else if( strncmp(zSynopsis+ii+1, "@NP", 3)==0 ){
+            sqlite3_context *pCtx = pOp->p4.pCtx;
+            if( pOp->p4type!=P4_FUNCCTX || pCtx->argc==1 ){
+              sqlite3_str_appendf(&x, "%d", v1);
+            }else if( pCtx->argc>1 ){
+              sqlite3_str_appendf(&x, "%d..%d", v1, v1+pCtx->argc-1);
+            }else if( x.accError==0 ){
+              assert( x.nChar>2 );
+              x.nChar -= 2;
+              ii++;
+            }
+            ii += 3;
+          }else{
+            sqlite3_str_appendf(&x, "%d", v1);
+            if( strncmp(zSynopsis+ii+1, "..P3", 4)==0 && pOp->p3==0 ){
+              ii += 4;
+            }
+          }
+        }
+      }else{
+        sqlite3_str_appendchar(&x, 1, c);
+      }
+    }
+    if( !seenCom && pOp->zComment ){
+      sqlite3_str_appendf(&x, "; %s", pOp->zComment);
+    }
+  }else if( pOp->zComment ){
+    sqlite3_str_appendall(&x, pOp->zComment);
+  }
+  if( (x.accError & SQLITE_NOMEM)!=0 && db!=0 ){
+    sqlite3OomFault(db);
+  }
+  return sqlite3StrAccumFinish(&x);
+}
+#endif /* SQLITE_ENABLE_EXPLAIN_COMMENTS */
+
+#if VDBE_DISPLAY_P4 && defined(SQLITE_ENABLE_CURSOR_HINTS)
+/*
+** Translate the P4.pExpr value for an OP_CursorHint opcode into text
+** that can be displayed in the P4 column of EXPLAIN output.
+*/
+static void displayP4Expr(StrAccum *p, Expr *pExpr){
+  const char *zOp = 0;
+  switch( pExpr->op ){
+    case TK_STRING:
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3_str_appendf(p, "%Q", pExpr->u.zToken);
+      break;
+    case TK_INTEGER:
+      sqlite3_str_appendf(p, "%d", pExpr->u.iValue);
+      break;
+    case TK_NULL:
+      sqlite3_str_appendf(p, "NULL");
+      break;
+    case TK_REGISTER: {
+      sqlite3_str_appendf(p, "r[%d]", pExpr->iTable);
+      break;
+    }
+    case TK_COLUMN: {
+      if( pExpr->iColumn<0 ){
+        sqlite3_str_appendf(p, "rowid");
+      }else{
+        sqlite3_str_appendf(p, "c%d", (int)pExpr->iColumn);
+      }
+      break;
+    }
+    case TK_LT:      zOp = "LT";      break;
+    case TK_LE:      zOp = "LE";      break;
+    case TK_GT:      zOp = "GT";      break;
+    case TK_GE:      zOp = "GE";      break;
+    case TK_NE:      zOp = "NE";      break;
+    case TK_EQ:      zOp = "EQ";      break;
+    case TK_IS:      zOp = "IS";      break;
+    case TK_ISNOT:   zOp = "ISNOT";   break;
+    case TK_AND:     zOp = "AND";     break;
+    case TK_OR:      zOp = "OR";      break;
+    case TK_PLUS:    zOp = "ADD";     break;
+    case TK_STAR:    zOp = "MUL";     break;
+    case TK_MINUS:   zOp = "SUB";     break;
+    case TK_REM:     zOp = "REM";     break;
+    case TK_BITAND:  zOp = "BITAND";  break;
+    case TK_BITOR:   zOp = "BITOR";   break;
+    case TK_SLASH:   zOp = "DIV";     break;
+    case TK_LSHIFT:  zOp = "LSHIFT";  break;
+    case TK_RSHIFT:  zOp = "RSHIFT";  break;
+    case TK_CONCAT:  zOp = "CONCAT";  break;
+    case TK_UMINUS:  zOp = "MINUS";   break;
+    case TK_UPLUS:   zOp = "PLUS";    break;
+    case TK_BITNOT:  zOp = "BITNOT";  break;
+    case TK_NOT:     zOp = "NOT";     break;
+    case TK_ISNULL:  zOp = "ISNULL";  break;
+    case TK_NOTNULL: zOp = "NOTNULL"; break;
+
+    default:
+      sqlite3_str_appendf(p, "%s", "expr");
+      break;
+  }
+
+  if( zOp ){
+    sqlite3_str_appendf(p, "%s(", zOp);
+    displayP4Expr(p, pExpr->pLeft);
+    if( pExpr->pRight ){
+      sqlite3_str_append(p, ",", 1);
+      displayP4Expr(p, pExpr->pRight);
+    }
+    sqlite3_str_append(p, ")", 1);
+  }
+}
+#endif /* VDBE_DISPLAY_P4 && defined(SQLITE_ENABLE_CURSOR_HINTS) */
+
+
+#if VDBE_DISPLAY_P4
+/*
+** Compute a string that describes the P4 parameter for an opcode.
+** Use zTemp for any required temporary buffer space.
+*/
+SQLITE_PRIVATE char *sqlite3VdbeDisplayP4(sqlite3 *db, Op *pOp){
+  char *zP4 = 0;
+  StrAccum x;
+
+  sqlite3StrAccumInit(&x, 0, 0, 0, SQLITE_MAX_LENGTH);
+  switch( pOp->p4type ){
+    case P4_KEYINFO: {
+      int j;
+      KeyInfo *pKeyInfo = pOp->p4.pKeyInfo;
+      assert( pKeyInfo->aSortFlags!=0 );
+      sqlite3_str_appendf(&x, "k(%d", pKeyInfo->nKeyField);
+      for(j=0; j<pKeyInfo->nKeyField; j++){
+        CollSeq *pColl = pKeyInfo->aColl[j];
+        const char *zColl = pColl ? pColl->zName : "";
+        if( strcmp(zColl, "BINARY")==0 ) zColl = "B";
+        sqlite3_str_appendf(&x, ",%s%s%s",
+               (pKeyInfo->aSortFlags[j] & KEYINFO_ORDER_DESC) ? "-" : "",
+               (pKeyInfo->aSortFlags[j] & KEYINFO_ORDER_BIGNULL)? "N." : "",
+               zColl);
+      }
+      sqlite3_str_append(&x, ")", 1);
+      break;
+    }
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+    case P4_EXPR: {
+      displayP4Expr(&x, pOp->p4.pExpr);
+      break;
+    }
+#endif
+    case P4_COLLSEQ: {
+      static const char *const encnames[] = {"?", "8", "16LE", "16BE"};
+      CollSeq *pColl = pOp->p4.pColl;
+      assert( pColl->enc<4 );
+      sqlite3_str_appendf(&x, "%.18s-%s", pColl->zName,
+                          encnames[pColl->enc]);
+      break;
+    }
+    case P4_FUNCDEF: {
+      FuncDef *pDef = pOp->p4.pFunc;
+      sqlite3_str_appendf(&x, "%s(%d)", pDef->zName, pDef->nArg);
+      break;
+    }
+    case P4_FUNCCTX: {
+      FuncDef *pDef = pOp->p4.pCtx->pFunc;
+      sqlite3_str_appendf(&x, "%s(%d)", pDef->zName, pDef->nArg);
+      break;
+    }
+    case P4_INT64: {
+      sqlite3_str_appendf(&x, "%lld", *pOp->p4.pI64);
+      break;
+    }
+    case P4_INT32: {
+      sqlite3_str_appendf(&x, "%d", pOp->p4.i);
+      break;
+    }
+    case P4_REAL: {
+      sqlite3_str_appendf(&x, "%.16g", *pOp->p4.pReal);
+      break;
+    }
+    case P4_MEM: {
+      Mem *pMem = pOp->p4.pMem;
+      if( pMem->flags & MEM_Str ){
+        zP4 = pMem->z;
+      }else if( pMem->flags & (MEM_Int|MEM_IntReal) ){
+        sqlite3_str_appendf(&x, "%lld", pMem->u.i);
+      }else if( pMem->flags & MEM_Real ){
+        sqlite3_str_appendf(&x, "%.16g", pMem->u.r);
+      }else if( pMem->flags & MEM_Null ){
+        zP4 = "NULL";
+      }else{
+        assert( pMem->flags & MEM_Blob );
+        zP4 = "(blob)";
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    case P4_VTAB: {
+      sqlite3_vtab *pVtab = pOp->p4.pVtab->pVtab;
+      sqlite3_str_appendf(&x, "vtab:%p", pVtab);
+      break;
+    }
+#endif
+    case P4_INTARRAY: {
+      u32 i;
+      u32 *ai = pOp->p4.ai;
+      u32 n = ai[0];   /* The first element of an INTARRAY is always the
+                       ** count of the number of elements to follow */
+      for(i=1; i<=n; i++){
+        sqlite3_str_appendf(&x, "%c%u", (i==1 ? '[' : ','), ai[i]);
+      }
+      sqlite3_str_append(&x, "]", 1);
+      break;
+    }
+    case P4_SUBPROGRAM: {
+      zP4 = "program";
+      break;
+    }
+    case P4_TABLE: {
+      zP4 = pOp->p4.pTab->zName;
+      break;
+    }
+    case P4_SUBRTNSIG: {
+      SubrtnSig *pSig = pOp->p4.pSubrtnSig;
+      sqlite3_str_appendf(&x, "subrtnsig:%d,%s", pSig->selId, pSig->zAff);
+      break;
+    }
+    default: {
+      zP4 = pOp->p4.z;
+    }
+  }
+  if( zP4 ) sqlite3_str_appendall(&x, zP4);
+  if( (x.accError & SQLITE_NOMEM)!=0 ){
+    sqlite3OomFault(db);
+  }
+  return sqlite3StrAccumFinish(&x);
+}
+#endif /* VDBE_DISPLAY_P4 */
+
+/*
+** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
+**
+** The prepared statements need to know in advance the complete set of
+** attached databases that will be use.  A mask of these databases
+** is maintained in p->btreeMask.  The p->lockMask value is the subset of
+** p->btreeMask of databases that will require a lock.
+*/
+SQLITE_PRIVATE void sqlite3VdbeUsesBtree(Vdbe *p, int i){
+  assert( i>=0 && i<p->db->nDb && i<(int)sizeof(yDbMask)*8 );
+  assert( i<(int)sizeof(p->btreeMask)*8 );
+  DbMaskSet(p->btreeMask, i);
+  if( i!=1 && sqlite3BtreeSharable(p->db->aDb[i].pBt) ){
+    DbMaskSet(p->lockMask, i);
+  }
+}
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE)
+/*
+** If SQLite is compiled to support shared-cache mode and to be threadsafe,
+** this routine obtains the mutex associated with each BtShared structure
+** that may be accessed by the VM passed as an argument. In doing so it also
+** sets the BtShared.db member of each of the BtShared structures, ensuring
+** that the correct busy-handler callback is invoked if required.
+**
+** If SQLite is not threadsafe but does support shared-cache mode, then
+** sqlite3BtreeEnter() is invoked to set the BtShared.db variables
+** of all of BtShared structures accessible via the database handle
+** associated with the VM.
+**
+** If SQLite is not threadsafe and does not support shared-cache mode, this
+** function is a no-op.
+**
+** The p->btreeMask field is a bitmask of all btrees that the prepared
+** statement p will ever use.  Let N be the number of bits in p->btreeMask
+** corresponding to btrees that use shared cache.  Then the runtime of
+** this routine is N*N.  But as N is rarely more than 1, this should not
+** be a problem.
+*/
+SQLITE_PRIVATE void sqlite3VdbeEnter(Vdbe *p){
+  int i;
+  sqlite3 *db;
+  Db *aDb;
+  int nDb;
+  if( DbMaskAllZero(p->lockMask) ) return;  /* The common case */
+  db = p->db;
+  aDb = db->aDb;
+  nDb = db->nDb;
+  for(i=0; i<nDb; i++){
+    if( i!=1 && DbMaskTest(p->lockMask,i) && ALWAYS(aDb[i].pBt!=0) ){
+      sqlite3BtreeEnter(aDb[i].pBt);
+    }
+  }
+}
+#endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0
+/*
+** Unlock all of the btrees previously locked by a call to sqlite3VdbeEnter().
+*/
+static SQLITE_NOINLINE void vdbeLeave(Vdbe *p){
+  int i;
+  sqlite3 *db;
+  Db *aDb;
+  int nDb;
+  db = p->db;
+  aDb = db->aDb;
+  nDb = db->nDb;
+  for(i=0; i<nDb; i++){
+    if( i!=1 && DbMaskTest(p->lockMask,i) && ALWAYS(aDb[i].pBt!=0) ){
+      sqlite3BtreeLeave(aDb[i].pBt);
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3VdbeLeave(Vdbe *p){
+  if( DbMaskAllZero(p->lockMask) ) return;  /* The common case */
+  vdbeLeave(p);
+}
+#endif
+
+#if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+/*
+** Print a single opcode.  This routine is used for debugging only.
+*/
+SQLITE_PRIVATE void sqlite3VdbePrintOp(FILE *pOut, int pc, VdbeOp *pOp){
+  char *zP4;
+  char *zCom;
+  sqlite3 dummyDb;
+  static const char *zFormat1 = "%4d %-13s %4d %4d %4d %-13s %.2X %s\n";
+  if( pOut==0 ) pOut = stdout;
+  sqlite3BeginBenignMalloc();
+  dummyDb.mallocFailed = 1;
+  zP4 = sqlite3VdbeDisplayP4(&dummyDb, pOp);
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  zCom = sqlite3VdbeDisplayComment(0, pOp, zP4);
+#else
+  zCom = 0;
+#endif
+  /* NB:  The sqlite3OpcodeName() function is implemented by code created
+  ** by the mkopcodeh.awk and mkopcodec.awk scripts which extract the
+  ** information from the vdbe.c source text */
+  fprintf(pOut, zFormat1, pc,
+      sqlite3OpcodeName(pOp->opcode), pOp->p1, pOp->p2, pOp->p3,
+      zP4 ? zP4 : "", pOp->p5,
+      zCom ? zCom : ""
+  );
+  fflush(pOut);
+  sqlite3_free(zP4);
+  sqlite3_free(zCom);
+  sqlite3EndBenignMalloc();
+}
+#endif
+
+/*
+** Initialize an array of N Mem element.
+**
+** This is a high-runner, so only those fields that really do need to
+** be initialized are set.  The Mem structure is organized so that
+** the fields that get initialized are nearby and hopefully on the same
+** cache line.
+**
+**    Mem.flags = flags
+**    Mem.db = db
+**    Mem.szMalloc = 0
+**
+** All other fields of Mem can safely remain uninitialized for now.  They
+** will be initialized before use.
+*/
+static void initMemArray(Mem *p, int N, sqlite3 *db, u16 flags){
+  assert( db!=0 );
+  if( N>0 ){
+    do{
+      p->flags = flags;
+      p->db = db;
+      p->szMalloc = 0;
+#ifdef SQLITE_DEBUG
+      p->pScopyFrom = 0;
+      p->bScopy = 0;
+#endif
+      p++;
+    }while( (--N)>0 );
+  }
+}
+
+/*
+** Release auxiliary memory held in an array of N Mem elements.
+**
+** After this routine returns, all Mem elements in the array will still
+** be valid.  Those Mem elements that were not holding auxiliary resources
+** will be unchanged.  Mem elements which had something freed will be
+** set to MEM_Undefined.
+*/
+static void releaseMemArray(Mem *p, int N){
+  if( p && N ){
+    Mem *pEnd = &p[N];
+    sqlite3 *db = p->db;
+    assert( db!=0 );
+    if( db->pnBytesFreed ){
+      do{
+        if( p->szMalloc ) sqlite3DbFree(db, p->zMalloc);
+      }while( (++p)<pEnd );
+      return;
+    }
+    do{
+      assert( (&p[1])==pEnd || p[0].db==p[1].db );
+      assert( sqlite3VdbeCheckMemInvariants(p) );
+
+      /* This block is really an inlined version of sqlite3VdbeMemRelease()
+      ** that takes advantage of the fact that the memory cell value is
+      ** being set to NULL after releasing any dynamic resources.
+      **
+      ** The justification for duplicating code is that according to
+      ** callgrind, this causes a certain test case to hit the CPU 4.7
+      ** percent less (x86 linux, gcc version 4.1.2, -O6) than if
+      ** sqlite3MemRelease() were called from here. With -O2, this jumps
+      ** to 6.6 percent. The test case is inserting 1000 rows into a table
+      ** with no indexes using a single prepared INSERT statement, bind()
+      ** and reset(). Inserts are grouped into a transaction.
+      */
+      testcase( p->flags & MEM_Agg );
+      testcase( p->flags & MEM_Dyn );
+      if( p->flags&(MEM_Agg|MEM_Dyn) ){
+        testcase( (p->flags & MEM_Dyn)!=0 && p->xDel==sqlite3VdbeFrameMemDel );
+        sqlite3VdbeMemRelease(p);
+        p->flags = MEM_Undefined;
+      }else if( p->szMalloc ){
+        sqlite3DbNNFreeNN(db, p->zMalloc);
+        p->szMalloc = 0;
+        p->flags = MEM_Undefined;
+      }
+#ifdef SQLITE_DEBUG
+      else{
+        p->flags = MEM_Undefined;
+      }
+#endif
+    }while( (++p)<pEnd );
+  }
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Verify that pFrame is a valid VdbeFrame pointer.  Return true if it is
+** and false if something is wrong.
+**
+** This routine is intended for use inside of assert() statements only.
+*/
+SQLITE_PRIVATE int sqlite3VdbeFrameIsValid(VdbeFrame *pFrame){
+  if( pFrame->iFrameMagic!=SQLITE_FRAME_MAGIC ) return 0;
+  return 1;
+}
+#endif
+
+
+/*
+** This is a destructor on a Mem object (which is really an sqlite3_value)
+** that deletes the Frame object that is attached to it as a blob.
+**
+** This routine does not delete the Frame right away.  It merely adds the
+** frame to a list of frames to be deleted when the Vdbe halts.
+*/
+SQLITE_PRIVATE void sqlite3VdbeFrameMemDel(void *pArg){
+  VdbeFrame *pFrame = (VdbeFrame*)pArg;
+  assert( sqlite3VdbeFrameIsValid(pFrame) );
+  pFrame->pParent = pFrame->v->pDelFrame;
+  pFrame->v->pDelFrame = pFrame;
+}
+
+#if defined(SQLITE_ENABLE_BYTECODE_VTAB) || !defined(SQLITE_OMIT_EXPLAIN)
+/*
+** Locate the next opcode to be displayed in EXPLAIN or EXPLAIN
+** QUERY PLAN output.
+**
+** Return SQLITE_ROW on success.  Return SQLITE_DONE if there are no
+** more opcodes to be displayed.
+*/
+SQLITE_PRIVATE int sqlite3VdbeNextOpcode(
+  Vdbe *p,         /* The statement being explained */
+  Mem *pSub,       /* Storage for keeping track of subprogram nesting */
+  int eMode,       /* 0: normal.  1: EQP.  2:  TablesUsed */
+  int *piPc,       /* IN/OUT: Current rowid.  Overwritten with next rowid */
+  int *piAddr,     /* OUT: Write index into (*paOp)[] here */
+  Op **paOp        /* OUT: Write the opcode array here */
+){
+  int nRow;                            /* Stop when row count reaches this */
+  int nSub = 0;                        /* Number of sub-vdbes seen so far */
+  SubProgram **apSub = 0;              /* Array of sub-vdbes */
+  int i;                               /* Next instruction address */
+  int rc = SQLITE_OK;                  /* Result code */
+  Op *aOp = 0;                         /* Opcode array */
+  int iPc;                             /* Rowid.  Copy of value in *piPc */
+
+  /* When the number of output rows reaches nRow, that means the
+  ** listing has finished and sqlite3_step() should return SQLITE_DONE.
+  ** nRow is the sum of the number of rows in the main program, plus
+  ** the sum of the number of rows in all trigger subprograms encountered
+  ** so far.  The nRow value will increase as new trigger subprograms are
+  ** encountered, but p->pc will eventually catch up to nRow.
+  */
+  nRow = p->nOp;
+  if( pSub!=0 ){
+    if( pSub->flags&MEM_Blob ){
+      /* pSub is initiallly NULL.  It is initialized to a BLOB by
+      ** the P4_SUBPROGRAM processing logic below */
+      nSub = pSub->n/sizeof(Vdbe*);
+      apSub = (SubProgram **)pSub->z;
+    }
+    for(i=0; i<nSub; i++){
+      nRow += apSub[i]->nOp;
+    }
+  }
+  iPc = *piPc;
+  while(1){  /* Loop exits via break */
+    i = iPc++;
+    if( i>=nRow ){
+      p->rc = SQLITE_OK;
+      rc = SQLITE_DONE;
+      break;
+    }
+    if( i<p->nOp ){
+      /* The rowid is small enough that we are still in the
+      ** main program. */
+      aOp = p->aOp;
+    }else{
+      /* We are currently listing subprograms.  Figure out which one and
+      ** pick up the appropriate opcode. */
+      int j;
+      i -= p->nOp;
+      assert( apSub!=0 );
+      assert( nSub>0 );
+      for(j=0; i>=apSub[j]->nOp; j++){
+        i -= apSub[j]->nOp;
+        assert( i<apSub[j]->nOp || j+1<nSub );
+      }
+      aOp = apSub[j]->aOp;
+    }
+
+    /* When an OP_Program opcode is encounter (the only opcode that has
+    ** a P4_SUBPROGRAM argument), expand the size of the array of subprograms
+    ** kept in p->aMem[9].z to hold the new program - assuming this subprogram
+    ** has not already been seen.
+    */
+    if( pSub!=0 && aOp[i].p4type==P4_SUBPROGRAM ){
+      int nByte = (nSub+1)*sizeof(SubProgram*);
+      int j;
+      for(j=0; j<nSub; j++){
+        if( apSub[j]==aOp[i].p4.pProgram ) break;
+      }
+      if( j==nSub ){
+        p->rc = sqlite3VdbeMemGrow(pSub, nByte, nSub!=0);
+        if( p->rc!=SQLITE_OK ){
+          rc = SQLITE_ERROR;
+          break;
+        }
+        apSub = (SubProgram **)pSub->z;
+        apSub[nSub++] = aOp[i].p4.pProgram;
+        MemSetTypeFlag(pSub, MEM_Blob);
+        pSub->n = nSub*sizeof(SubProgram*);
+        nRow += aOp[i].p4.pProgram->nOp;
+      }
+    }
+    if( eMode==0 ) break;
+#ifdef SQLITE_ENABLE_BYTECODE_VTAB
+    if( eMode==2 ){
+      Op *pOp = aOp + i;
+      if( pOp->opcode==OP_OpenRead ) break;
+      if( pOp->opcode==OP_OpenWrite && (pOp->p5 & OPFLAG_P2ISREG)==0 ) break;
+      if( pOp->opcode==OP_ReopenIdx ) break;
+    }else
+#endif
+    {
+      assert( eMode==1 );
+      if( aOp[i].opcode==OP_Explain ) break;
+      if( aOp[i].opcode==OP_Init && iPc>1 ) break;
+    }
+  }
+  *piPc = iPc;
+  *piAddr = i;
+  *paOp = aOp;
+  return rc;
+}
+#endif /* SQLITE_ENABLE_BYTECODE_VTAB || !SQLITE_OMIT_EXPLAIN */
+
+
+/*
+** Delete a VdbeFrame object and its contents. VdbeFrame objects are
+** allocated by the OP_Program opcode in sqlite3VdbeExec().
+*/
+SQLITE_PRIVATE void sqlite3VdbeFrameDelete(VdbeFrame *p){
+  int i;
+  Mem *aMem = VdbeFrameMem(p);
+  VdbeCursor **apCsr = (VdbeCursor **)&aMem[p->nChildMem];
+  assert( sqlite3VdbeFrameIsValid(p) );
+  for(i=0; i<p->nChildCsr; i++){
+    if( apCsr[i] ) sqlite3VdbeFreeCursorNN(p->v, apCsr[i]);
+  }
+  releaseMemArray(aMem, p->nChildMem);
+  sqlite3VdbeDeleteAuxData(p->v->db, &p->pAuxData, -1, 0);
+  sqlite3DbFree(p->v->db, p);
+}
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Give a listing of the program in the virtual machine.
+**
+** The interface is the same as sqlite3VdbeExec().  But instead of
+** running the code, it invokes the callback once for each instruction.
+** This feature is used to implement "EXPLAIN".
+**
+** When p->explain==1, each instruction is listed.  When
+** p->explain==2, only OP_Explain instructions are listed and these
+** are shown in a different format.  p->explain==2 is used to implement
+** EXPLAIN QUERY PLAN.
+** 2018-04-24:  In p->explain==2 mode, the OP_Init opcodes of triggers
+** are also shown, so that the boundaries between the main program and
+** each trigger are clear.
+**
+** When p->explain==1, first the main program is listed, then each of
+** the trigger subprograms are listed one by one.
+*/
+SQLITE_PRIVATE int sqlite3VdbeList(
+  Vdbe *p                   /* The VDBE */
+){
+  Mem *pSub = 0;                       /* Memory cell hold array of subprogs */
+  sqlite3 *db = p->db;                 /* The database connection */
+  int i;                               /* Loop counter */
+  int rc = SQLITE_OK;                  /* Return code */
+  Mem *pMem = &p->aMem[1];             /* First Mem of result set */
+  int bListSubprogs = (p->explain==1 || (db->flags & SQLITE_TriggerEQP)!=0);
+  Op *aOp;                             /* Array of opcodes */
+  Op *pOp;                             /* Current opcode */
+
+  assert( p->explain );
+  assert( p->eVdbeState==VDBE_RUN_STATE );
+  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY || p->rc==SQLITE_NOMEM );
+
+  /* Even though this opcode does not use dynamic strings for
+  ** the result, result columns may become dynamic if the user calls
+  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
+  */
+  releaseMemArray(pMem, 8);
+
+  if( p->rc==SQLITE_NOMEM ){
+    /* This happens if a malloc() inside a call to sqlite3_column_text() or
+    ** sqlite3_column_text16() failed.  */
+    sqlite3OomFault(db);
+    return SQLITE_ERROR;
+  }
+
+  if( bListSubprogs ){
+    /* The first 8 memory cells are used for the result set.  So we will
+    ** commandeer the 9th cell to use as storage for an array of pointers
+    ** to trigger subprograms.  The VDBE is guaranteed to have at least 9
+    ** cells.  */
+    assert( p->nMem>9 );
+    pSub = &p->aMem[9];
+  }else{
+    pSub = 0;
+  }
+
+  /* Figure out which opcode is next to display */
+  rc = sqlite3VdbeNextOpcode(p, pSub, p->explain==2, &p->pc, &i, &aOp);
+
+  if( rc==SQLITE_OK ){
+    pOp = aOp + i;
+    if( AtomicLoad(&db->u1.isInterrupted) ){
+      p->rc = SQLITE_INTERRUPT;
+      rc = SQLITE_ERROR;
+      sqlite3VdbeError(p, sqlite3ErrStr(p->rc));
+    }else{
+      char *zP4 = sqlite3VdbeDisplayP4(db, pOp);
+      if( p->explain==2 ){
+        sqlite3VdbeMemSetInt64(pMem, pOp->p1);
+        sqlite3VdbeMemSetInt64(pMem+1, pOp->p2);
+        sqlite3VdbeMemSetInt64(pMem+2, pOp->p3);
+        sqlite3VdbeMemSetStr(pMem+3, zP4, -1, SQLITE_UTF8, sqlite3_free);
+        assert( p->nResColumn==4 );
+      }else{
+        sqlite3VdbeMemSetInt64(pMem+0, i);
+        sqlite3VdbeMemSetStr(pMem+1, (char*)sqlite3OpcodeName(pOp->opcode),
+                             -1, SQLITE_UTF8, SQLITE_STATIC);
+        sqlite3VdbeMemSetInt64(pMem+2, pOp->p1);
+        sqlite3VdbeMemSetInt64(pMem+3, pOp->p2);
+        sqlite3VdbeMemSetInt64(pMem+4, pOp->p3);
+        /* pMem+5 for p4 is done last */
+        sqlite3VdbeMemSetInt64(pMem+6, pOp->p5);
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+        {
+          char *zCom = sqlite3VdbeDisplayComment(db, pOp, zP4);
+          sqlite3VdbeMemSetStr(pMem+7, zCom, -1, SQLITE_UTF8, sqlite3_free);
+        }
+#else
+        sqlite3VdbeMemSetNull(pMem+7);
+#endif
+        sqlite3VdbeMemSetStr(pMem+5, zP4, -1, SQLITE_UTF8, sqlite3_free);
+        assert( p->nResColumn==8 );
+      }
+      p->pResultRow = pMem;
+      if( db->mallocFailed ){
+        p->rc = SQLITE_NOMEM;
+        rc = SQLITE_ERROR;
+      }else{
+        p->rc = SQLITE_OK;
+        rc = SQLITE_ROW;
+      }
+    }
+  }
+  return rc;
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+
+#ifdef SQLITE_DEBUG
+/*
+** Print the SQL that was used to generate a VDBE program.
+*/
+SQLITE_PRIVATE void sqlite3VdbePrintSql(Vdbe *p){
+  const char *z = 0;
+  if( p->zSql ){
+    z = p->zSql;
+  }else if( p->nOp>=1 ){
+    const VdbeOp *pOp = &p->aOp[0];
+    if( pOp->opcode==OP_Init && pOp->p4.z!=0 ){
+      z = pOp->p4.z;
+      while( sqlite3Isspace(*z) ) z++;
+    }
+  }
+  if( z ) printf("SQL: [%s]\n", z);
+}
+#endif
+
+#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
+/*
+** Print an IOTRACE message showing SQL content.
+*/
+SQLITE_PRIVATE void sqlite3VdbeIOTraceSql(Vdbe *p){
+  int nOp = p->nOp;
+  VdbeOp *pOp;
+  if( sqlite3IoTrace==0 ) return;
+  if( nOp<1 ) return;
+  pOp = &p->aOp[0];
+  if( pOp->opcode==OP_Init && pOp->p4.z!=0 ){
+    int i, j;
+    char z[1000];
+    sqlite3_snprintf(sizeof(z), z, "%s", pOp->p4.z);
+    for(i=0; sqlite3Isspace(z[i]); i++){}
+    for(j=0; z[i]; i++){
+      if( sqlite3Isspace(z[i]) ){
+        if( z[i-1]!=' ' ){
+          z[j++] = ' ';
+        }
+      }else{
+        z[j++] = z[i];
+      }
+    }
+    z[j] = 0;
+    sqlite3IoTrace("SQL %s\n", z);
+  }
+}
+#endif /* !SQLITE_OMIT_TRACE && SQLITE_ENABLE_IOTRACE */
+
+/* An instance of this object describes bulk memory available for use
+** by subcomponents of a prepared statement.  Space is allocated out
+** of a ReusableSpace object by the allocSpace() routine below.
+*/
+struct ReusableSpace {
+  u8 *pSpace;            /* Available memory */
+  sqlite3_int64 nFree;   /* Bytes of available memory */
+  sqlite3_int64 nNeeded; /* Total bytes that could not be allocated */
+};
+
+/* Try to allocate nByte bytes of 8-byte aligned bulk memory for pBuf
+** from the ReusableSpace object.  Return a pointer to the allocated
+** memory on success.  If insufficient memory is available in the
+** ReusableSpace object, increase the ReusableSpace.nNeeded
+** value by the amount needed and return NULL.
+**
+** If pBuf is not initially NULL, that means that the memory has already
+** been allocated by a prior call to this routine, so just return a copy
+** of pBuf and leave ReusableSpace unchanged.
+**
+** This allocator is employed to repurpose unused slots at the end of the
+** opcode array of prepared state for other memory needs of the prepared
+** statement.
+*/
+static void *allocSpace(
+  struct ReusableSpace *p,  /* Bulk memory available for allocation */
+  void *pBuf,               /* Pointer to a prior allocation */
+  sqlite3_int64 nByte       /* Bytes of memory needed. */
+){
+  assert( EIGHT_BYTE_ALIGNMENT(p->pSpace) );
+  if( pBuf==0 ){
+    nByte = ROUND8P(nByte);
+    if( nByte <= p->nFree ){
+      p->nFree -= nByte;
+      pBuf = &p->pSpace[p->nFree];
+    }else{
+      p->nNeeded += nByte;
+    }
+  }
+  assert( EIGHT_BYTE_ALIGNMENT(pBuf) );
+  return pBuf;
+}
+
+/*
+** Rewind the VDBE back to the beginning in preparation for
+** running it.
+*/
+SQLITE_PRIVATE void sqlite3VdbeRewind(Vdbe *p){
+#if defined(SQLITE_DEBUG)
+  int i;
+#endif
+  assert( p!=0 );
+  assert( p->eVdbeState==VDBE_INIT_STATE
+       || p->eVdbeState==VDBE_READY_STATE
+       || p->eVdbeState==VDBE_HALT_STATE );
+
+  /* There should be at least one opcode.
+  */
+  assert( p->nOp>0 );
+
+  p->eVdbeState = VDBE_READY_STATE;
+
+#ifdef SQLITE_DEBUG
+  for(i=0; i<p->nMem; i++){
+    assert( p->aMem[i].db==p->db );
+  }
+#endif
+  p->pc = -1;
+  p->rc = SQLITE_OK;
+  p->errorAction = OE_Abort;
+  p->nChange = 0;
+  p->cacheCtr = 1;
+  p->minWriteFileFormat = 255;
+  p->iStatement = 0;
+  p->nFkConstraint = 0;
+#ifdef VDBE_PROFILE
+  for(i=0; i<p->nOp; i++){
+    p->aOp[i].nExec = 0;
+    p->aOp[i].nCycle = 0;
+  }
+#endif
+}
+
+/*
+** Prepare a virtual machine for execution for the first time after
+** creating the virtual machine.  This involves things such
+** as allocating registers and initializing the program counter.
+** After the VDBE has be prepped, it can be executed by one or more
+** calls to sqlite3VdbeExec().
+**
+** This function may be called exactly once on each virtual machine.
+** After this routine is called the VM has been "packaged" and is ready
+** to run.  After this routine is called, further calls to
+** sqlite3VdbeAddOp() functions are prohibited.  This routine disconnects
+** the Vdbe from the Parse object that helped generate it so that the
+** the Vdbe becomes an independent entity and the Parse object can be
+** destroyed.
+**
+** Use the sqlite3VdbeRewind() procedure to restore a virtual machine back
+** to its initial state after it has been run.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMakeReady(
+  Vdbe *p,                       /* The VDBE */
+  Parse *pParse                  /* Parsing context */
+){
+  sqlite3 *db;                   /* The database connection */
+  int nVar;                      /* Number of parameters */
+  int nMem;                      /* Number of VM memory registers */
+  int nCursor;                   /* Number of cursors required */
+  int nArg;                      /* Number of arguments in subprograms */
+  int n;                         /* Loop counter */
+  struct ReusableSpace x;        /* Reusable bulk memory */
+
+  assert( p!=0 );
+  assert( p->nOp>0 );
+  assert( pParse!=0 );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
+  assert( pParse==p->pParse );
+  assert( pParse->db==p->db );
+  p->pVList = pParse->pVList;
+  pParse->pVList =  0;
+  db = p->db;
+  assert( db->mallocFailed==0 );
+  nVar = pParse->nVar;
+  nMem = pParse->nMem;
+  nCursor = pParse->nTab;
+  nArg = pParse->nMaxArg;
+
+  /* Each cursor uses a memory cell.  The first cursor (cursor 0) can
+  ** use aMem[0] which is not otherwise used by the VDBE program.  Allocate
+  ** space at the end of aMem[] for cursors 1 and greater.
+  ** See also: allocateCursor().
+  */
+  nMem += nCursor;
+  if( nCursor==0 && nMem>0 ) nMem++;  /* Space for aMem[0] even if not used */
+
+  /* Figure out how much reusable memory is available at the end of the
+  ** opcode array.  This extra memory will be reallocated for other elements
+  ** of the prepared statement.
+  */
+  n = ROUND8P(sizeof(Op)*p->nOp);             /* Bytes of opcode memory used */
+  x.pSpace = &((u8*)p->aOp)[n];               /* Unused opcode memory */
+  assert( EIGHT_BYTE_ALIGNMENT(x.pSpace) );
+  x.nFree = ROUNDDOWN8(pParse->szOpAlloc - n);  /* Bytes of unused memory */
+  assert( x.nFree>=0 );
+  assert( EIGHT_BYTE_ALIGNMENT(&x.pSpace[x.nFree]) );
+
+  resolveP2Values(p, &nArg);
+  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
+  if( pParse->explain ){
+    if( nMem<10 ) nMem = 10;
+    p->explain = pParse->explain;
+    p->nResColumn = 12 - 4*p->explain;
+  }
+  p->expired = 0;
+
+  /* Memory for registers, parameters, cursor, etc, is allocated in one or two
+  ** passes.  On the first pass, we try to reuse unused memory at the
+  ** end of the opcode array.  If we are unable to satisfy all memory
+  ** requirements by reusing the opcode array tail, then the second
+  ** pass will fill in the remainder using a fresh memory allocation.
+  **
+  ** This two-pass approach that reuses as much memory as possible from
+  ** the leftover memory at the end of the opcode array.  This can significantly
+  ** reduce the amount of memory held by a prepared statement.
+  */
+  x.nNeeded = 0;
+  p->aMem = allocSpace(&x, 0, nMem*sizeof(Mem));
+  p->aVar = allocSpace(&x, 0, nVar*sizeof(Mem));
+  p->apArg = allocSpace(&x, 0, nArg*sizeof(Mem*));
+  p->apCsr = allocSpace(&x, 0, nCursor*sizeof(VdbeCursor*));
+  if( x.nNeeded ){
+    x.pSpace = p->pFree = sqlite3DbMallocRawNN(db, x.nNeeded);
+    x.nFree = x.nNeeded;
+    if( !db->mallocFailed ){
+      p->aMem = allocSpace(&x, p->aMem, nMem*sizeof(Mem));
+      p->aVar = allocSpace(&x, p->aVar, nVar*sizeof(Mem));
+      p->apArg = allocSpace(&x, p->apArg, nArg*sizeof(Mem*));
+      p->apCsr = allocSpace(&x, p->apCsr, nCursor*sizeof(VdbeCursor*));
+    }
+  }
+
+  if( db->mallocFailed ){
+    p->nVar = 0;
+    p->nCursor = 0;
+    p->nMem = 0;
+  }else{
+    p->nCursor = nCursor;
+    p->nVar = (ynVar)nVar;
+    initMemArray(p->aVar, nVar, db, MEM_Null);
+    p->nMem = nMem;
+    initMemArray(p->aMem, nMem, db, MEM_Undefined);
+    memset(p->apCsr, 0, nCursor*sizeof(VdbeCursor*));
+  }
+  sqlite3VdbeRewind(p);
+}
+
+/*
+** Close a VDBE cursor and release all the resources that cursor
+** happens to hold.
+*/
+SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *p, VdbeCursor *pCx){
+  if( pCx ) sqlite3VdbeFreeCursorNN(p,pCx);
+}
+static SQLITE_NOINLINE void freeCursorWithCache(Vdbe *p, VdbeCursor *pCx){
+  VdbeTxtBlbCache *pCache = pCx->pCache;
+  assert( pCx->colCache );
+  pCx->colCache = 0;
+  pCx->pCache = 0;
+  if( pCache->pCValue ){
+    sqlite3RCStrUnref(pCache->pCValue);
+    pCache->pCValue = 0;
+  }
+  sqlite3DbFree(p->db, pCache);
+  sqlite3VdbeFreeCursorNN(p, pCx);
+}
+SQLITE_PRIVATE void sqlite3VdbeFreeCursorNN(Vdbe *p, VdbeCursor *pCx){
+  if( pCx->colCache ){
+    freeCursorWithCache(p, pCx);
+    return;
+  }
+  switch( pCx->eCurType ){
+    case CURTYPE_SORTER: {
+      sqlite3VdbeSorterClose(p->db, pCx);
+      break;
+    }
+    case CURTYPE_BTREE: {
+      assert( pCx->uc.pCursor!=0 );
+      sqlite3BtreeCloseCursor(pCx->uc.pCursor);
+      break;
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    case CURTYPE_VTAB: {
+      sqlite3_vtab_cursor *pVCur = pCx->uc.pVCur;
+      const sqlite3_module *pModule = pVCur->pVtab->pModule;
+      assert( pVCur->pVtab->nRef>0 );
+      pVCur->pVtab->nRef--;
+      pModule->xClose(pVCur);
+      break;
+    }
+#endif
+  }
+}
+
+/*
+** Close all cursors in the current frame.
+*/
+static void closeCursorsInFrame(Vdbe *p){
+  int i;
+  for(i=0; i<p->nCursor; i++){
+    VdbeCursor *pC = p->apCsr[i];
+    if( pC ){
+      sqlite3VdbeFreeCursorNN(p, pC);
+      p->apCsr[i] = 0;
+    }
+  }
+}
+
+/*
+** Copy the values stored in the VdbeFrame structure to its Vdbe. This
+** is used, for example, when a trigger sub-program is halted to restore
+** control to the main program.
+*/
+SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *pFrame){
+  Vdbe *v = pFrame->v;
+  closeCursorsInFrame(v);
+  v->aOp = pFrame->aOp;
+  v->nOp = pFrame->nOp;
+  v->aMem = pFrame->aMem;
+  v->nMem = pFrame->nMem;
+  v->apCsr = pFrame->apCsr;
+  v->nCursor = pFrame->nCursor;
+  v->db->lastRowid = pFrame->lastRowid;
+  v->nChange = pFrame->nChange;
+  v->db->nChange = pFrame->nDbChange;
+  sqlite3VdbeDeleteAuxData(v->db, &v->pAuxData, -1, 0);
+  v->pAuxData = pFrame->pAuxData;
+  pFrame->pAuxData = 0;
+  return pFrame->pc;
+}
+
+/*
+** Close all cursors.
+**
+** Also release any dynamic memory held by the VM in the Vdbe.aMem memory
+** cell array. This is necessary as the memory cell array may contain
+** pointers to VdbeFrame objects, which may in turn contain pointers to
+** open cursors.
+*/
+static void closeAllCursors(Vdbe *p){
+  if( p->pFrame ){
+    VdbeFrame *pFrame;
+    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
+    sqlite3VdbeFrameRestore(pFrame);
+    p->pFrame = 0;
+    p->nFrame = 0;
+  }
+  assert( p->nFrame==0 );
+  closeCursorsInFrame(p);
+  releaseMemArray(p->aMem, p->nMem);
+  while( p->pDelFrame ){
+    VdbeFrame *pDel = p->pDelFrame;
+    p->pDelFrame = pDel->pParent;
+    sqlite3VdbeFrameDelete(pDel);
+  }
+
+  /* Delete any auxdata allocations made by the VM */
+  if( p->pAuxData ) sqlite3VdbeDeleteAuxData(p->db, &p->pAuxData, -1, 0);
+  assert( p->pAuxData==0 );
+}
+
+/*
+** Set the number of result columns that will be returned by this SQL
+** statement. This is now set at compile time, rather than during
+** execution of the vdbe program so that sqlite3_column_count() can
+** be called on an SQL statement before sqlite3_step().
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
+  int n;
+  sqlite3 *db = p->db;
+
+  if( p->nResAlloc ){
+    releaseMemArray(p->aColName, p->nResAlloc*COLNAME_N);
+    sqlite3DbFree(db, p->aColName);
+  }
+  n = nResColumn*COLNAME_N;
+  p->nResColumn = p->nResAlloc = (u16)nResColumn;
+  p->aColName = (Mem*)sqlite3DbMallocRawNN(db, sizeof(Mem)*n );
+  if( p->aColName==0 ) return;
+  initMemArray(p->aColName, n, db, MEM_Null);
+}
+
+/*
+** Set the name of the idx'th column to be returned by the SQL statement.
+** zName must be a pointer to a nul terminated string.
+**
+** This call must be made after a call to sqlite3VdbeSetNumCols().
+**
+** The final parameter, xDel, must be one of SQLITE_DYNAMIC, SQLITE_STATIC
+** or SQLITE_TRANSIENT. If it is SQLITE_DYNAMIC, then the buffer pointed
+** to by zName will be freed by sqlite3DbFree() when the vdbe is destroyed.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSetColName(
+  Vdbe *p,                         /* Vdbe being configured */
+  int idx,                         /* Index of column zName applies to */
+  int var,                         /* One of the COLNAME_* constants */
+  const char *zName,               /* Pointer to buffer containing name */
+  void (*xDel)(void*)              /* Memory management strategy for zName */
+){
+  int rc;
+  Mem *pColName;
+  assert( idx<p->nResAlloc );
+  assert( var<COLNAME_N );
+  if( p->db->mallocFailed ){
+    assert( !zName || xDel!=SQLITE_DYNAMIC );
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( p->aColName!=0 );
+  pColName = &(p->aColName[idx+var*p->nResAlloc]);
+  rc = sqlite3VdbeMemSetStr(pColName, zName, -1, SQLITE_UTF8, xDel);
+  assert( rc!=0 || !zName || (pColName->flags&MEM_Term)!=0 );
+  return rc;
+}
+
+/*
+** A read or write transaction may or may not be active on database handle
+** db. If a transaction is active, commit it. If there is a
+** write-transaction spanning more than one database file, this routine
+** takes care of the super-journal trickery.
+*/
+static int vdbeCommit(sqlite3 *db, Vdbe *p){
+  int i;
+  int nTrans = 0;  /* Number of databases with an active write-transaction
+                   ** that are candidates for a two-phase commit using a
+                   ** super-journal */
+  int rc = SQLITE_OK;
+  int needXcommit = 0;
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+  /* With this option, sqlite3VtabSync() is defined to be simply
+  ** SQLITE_OK so p is not used.
+  */
+  UNUSED_PARAMETER(p);
+#endif
+
+  /* Before doing anything else, call the xSync() callback for any
+  ** virtual module tables written in this transaction. This has to
+  ** be done before determining whether a super-journal file is
+  ** required, as an xSync() callback may add an attached database
+  ** to the transaction.
+  */
+  rc = sqlite3VtabSync(db, p);
+
+  /* This loop determines (a) if the commit hook should be invoked and
+  ** (b) how many database files have open write transactions, not
+  ** including the temp database. (b) is important because if more than
+  ** one database file has an open write transaction, a super-journal
+  ** file is required for an atomic commit.
+  */
+  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( sqlite3BtreeTxnState(pBt)==SQLITE_TXN_WRITE ){
+      /* Whether or not a database might need a super-journal depends upon
+      ** its journal mode (among other things).  This matrix determines which
+      ** journal modes use a super-journal and which do not */
+      static const u8 aMJNeeded[] = {
+        /* DELETE   */  1,
+        /* PERSIST   */ 1,
+        /* OFF       */ 0,
+        /* TRUNCATE  */ 1,
+        /* MEMORY    */ 0,
+        /* WAL       */ 0
+      };
+      Pager *pPager;   /* Pager associated with pBt */
+      needXcommit = 1;
+      sqlite3BtreeEnter(pBt);
+      pPager = sqlite3BtreePager(pBt);
+      if( db->aDb[i].safety_level!=PAGER_SYNCHRONOUS_OFF
+       && aMJNeeded[sqlite3PagerGetJournalMode(pPager)]
+       && sqlite3PagerIsMemdb(pPager)==0
+      ){
+        assert( i!=1 );
+        nTrans++;
+      }
+      rc = sqlite3PagerExclusiveLock(pPager);
+      sqlite3BtreeLeave(pBt);
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* If there are any write-transactions at all, invoke the commit hook */
+  if( needXcommit && db->xCommitCallback ){
+    rc = db->xCommitCallback(db->pCommitArg);
+    if( rc ){
+      return SQLITE_CONSTRAINT_COMMITHOOK;
+    }
+  }
+
+  /* The simple case - no more than one database file (not counting the
+  ** TEMP database) has a transaction active.   There is no need for the
+  ** super-journal.
+  **
+  ** If the return value of sqlite3BtreeGetFilename() is a zero length
+  ** string, it means the main database is :memory: or a temp file.  In
+  ** that case we do not support atomic multi-file commits, so use the
+  ** simple case then too.
+  */
+  if( 0==sqlite3Strlen30(sqlite3BtreeGetFilename(db->aDb[0].pBt))
+   || nTrans<=1
+  ){
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeCommitPhaseOne(pBt, 0);
+      }
+    }
+
+    /* Do the commit only if all databases successfully complete phase 1.
+    ** If one of the BtreeCommitPhaseOne() calls fails, this indicates an
+    ** IO error while deleting or truncating a journal file. It is unlikely,
+    ** but could happen. In this case abandon processing and return the error.
+    */
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeCommitPhaseTwo(pBt, 0);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3VtabCommit(db);
+    }
+  }
+
+  /* The complex case - There is a multi-file write-transaction active.
+  ** This requires a super-journal file to ensure the transaction is
+  ** committed atomically.
+  */
+#ifndef SQLITE_OMIT_DISKIO
+  else{
+    sqlite3_vfs *pVfs = db->pVfs;
+    char *zSuper = 0;   /* File-name for the super-journal */
+    char const *zMainFile = sqlite3BtreeGetFilename(db->aDb[0].pBt);
+    sqlite3_file *pSuperJrnl = 0;
+    i64 offset = 0;
+    int res;
+    int retryCount = 0;
+    int nMainFile;
+
+    /* Select a super-journal file name */
+    nMainFile = sqlite3Strlen30(zMainFile);
+    zSuper = sqlite3MPrintf(db, "%.4c%s%.16c", 0,zMainFile,0);
+    if( zSuper==0 ) return SQLITE_NOMEM_BKPT;
+    zSuper += 4;
+    do {
+      u32 iRandom;
+      if( retryCount ){
+        if( retryCount>100 ){
+          sqlite3_log(SQLITE_FULL, "MJ delete: %s", zSuper);
+          sqlite3OsDelete(pVfs, zSuper, 0);
+          break;
+        }else if( retryCount==1 ){
+          sqlite3_log(SQLITE_FULL, "MJ collide: %s", zSuper);
+        }
+      }
+      retryCount++;
+      sqlite3_randomness(sizeof(iRandom), &iRandom);
+      sqlite3_snprintf(13, &zSuper[nMainFile], "-mj%06X9%02X",
+                               (iRandom>>8)&0xffffff, iRandom&0xff);
+      /* The antipenultimate character of the super-journal name must
+      ** be "9" to avoid name collisions when using 8+3 filenames. */
+      assert( zSuper[sqlite3Strlen30(zSuper)-3]=='9' );
+      sqlite3FileSuffix3(zMainFile, zSuper);
+      rc = sqlite3OsAccess(pVfs, zSuper, SQLITE_ACCESS_EXISTS, &res);
+    }while( rc==SQLITE_OK && res );
+    if( rc==SQLITE_OK ){
+      /* Open the super-journal. */
+      rc = sqlite3OsOpenMalloc(pVfs, zSuper, &pSuperJrnl,
+          SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|
+          SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_SUPER_JOURNAL, 0
+      );
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3DbFree(db, zSuper-4);
+      return rc;
+    }
+
+    /* Write the name of each database file in the transaction into the new
+    ** super-journal file. If an error occurs at this point close
+    ** and delete the super-journal file. All the individual journal files
+    ** still have 'null' as the super-journal pointer, so they will roll
+    ** back independently if a failure occurs.
+    */
+    for(i=0; i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( sqlite3BtreeTxnState(pBt)==SQLITE_TXN_WRITE ){
+        char const *zFile = sqlite3BtreeGetJournalname(pBt);
+        if( zFile==0 ){
+          continue;  /* Ignore TEMP and :memory: databases */
+        }
+        assert( zFile[0]!=0 );
+        rc = sqlite3OsWrite(pSuperJrnl, zFile, sqlite3Strlen30(zFile)+1,offset);
+        offset += sqlite3Strlen30(zFile)+1;
+        if( rc!=SQLITE_OK ){
+          sqlite3OsCloseFree(pSuperJrnl);
+          sqlite3OsDelete(pVfs, zSuper, 0);
+          sqlite3DbFree(db, zSuper-4);
+          return rc;
+        }
+      }
+    }
+
+    /* Sync the super-journal file. If the IOCAP_SEQUENTIAL device
+    ** flag is set this is not required.
+    */
+    if( 0==(sqlite3OsDeviceCharacteristics(pSuperJrnl)&SQLITE_IOCAP_SEQUENTIAL)
+     && SQLITE_OK!=(rc = sqlite3OsSync(pSuperJrnl, SQLITE_SYNC_NORMAL))
+    ){
+      sqlite3OsCloseFree(pSuperJrnl);
+      sqlite3OsDelete(pVfs, zSuper, 0);
+      sqlite3DbFree(db, zSuper-4);
+      return rc;
+    }
+
+    /* Sync all the db files involved in the transaction. The same call
+    ** sets the super-journal pointer in each individual journal. If
+    ** an error occurs here, do not delete the super-journal file.
+    **
+    ** If the error occurs during the first call to
+    ** sqlite3BtreeCommitPhaseOne(), then there is a chance that the
+    ** super-journal file will be orphaned. But we cannot delete it,
+    ** in case the super-journal file name was written into the journal
+    ** file before the failure occurred.
+    */
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeCommitPhaseOne(pBt, zSuper);
+      }
+    }
+    sqlite3OsCloseFree(pSuperJrnl);
+    assert( rc!=SQLITE_BUSY );
+    if( rc!=SQLITE_OK ){
+      sqlite3DbFree(db, zSuper-4);
+      return rc;
+    }
+
+    /* Delete the super-journal file. This commits the transaction. After
+    ** doing this the directory is synced again before any individual
+    ** transaction files are deleted.
+    */
+    rc = sqlite3OsDelete(pVfs, zSuper, 1);
+    sqlite3DbFree(db, zSuper-4);
+    zSuper = 0;
+    if( rc ){
+      return rc;
+    }
+
+    /* All files and directories have already been synced, so the following
+    ** calls to sqlite3BtreeCommitPhaseTwo() are only closing files and
+    ** deleting or truncating journals. If something goes wrong while
+    ** this is happening we don't really care. The integrity of the
+    ** transaction is already guaranteed, but some stray 'cold' journals
+    ** may be lying around. Returning an error code won't help matters.
+    */
+    disable_simulated_io_errors();
+    sqlite3BeginBenignMalloc();
+    for(i=0; i<db->nDb; i++){
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        sqlite3BtreeCommitPhaseTwo(pBt, 1);
+      }
+    }
+    sqlite3EndBenignMalloc();
+    enable_simulated_io_errors();
+
+    sqlite3VtabCommit(db);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** This routine checks that the sqlite3.nVdbeActive count variable
+** matches the number of vdbe's in the list sqlite3.pVdbe that are
+** currently active. An assertion fails if the two counts do not match.
+** This is an internal self-check only - it is not an essential processing
+** step.
+**
+** This is a no-op if NDEBUG is defined.
+*/
+#ifndef NDEBUG
+static void checkActiveVdbeCnt(sqlite3 *db){
+  Vdbe *p;
+  int cnt = 0;
+  int nWrite = 0;
+  int nRead = 0;
+  p = db->pVdbe;
+  while( p ){
+    if( sqlite3_stmt_busy((sqlite3_stmt*)p) ){
+      cnt++;
+      if( p->readOnly==0 ) nWrite++;
+      if( p->bIsReader ) nRead++;
+    }
+    p = p->pVNext;
+  }
+  assert( cnt==db->nVdbeActive );
+  assert( nWrite==db->nVdbeWrite );
+  assert( nRead==db->nVdbeRead );
+}
+#else
+#define checkActiveVdbeCnt(x)
+#endif
+
+/*
+** If the Vdbe passed as the first argument opened a statement-transaction,
+** close it now. Argument eOp must be either SAVEPOINT_ROLLBACK or
+** SAVEPOINT_RELEASE. If it is SAVEPOINT_ROLLBACK, then the statement
+** transaction is rolled back. If eOp is SAVEPOINT_RELEASE, then the
+** statement transaction is committed.
+**
+** If an IO error occurs, an SQLITE_IOERR_XXX error code is returned.
+** Otherwise SQLITE_OK.
+*/
+static SQLITE_NOINLINE int vdbeCloseStatement(Vdbe *p, int eOp){
+  sqlite3 *const db = p->db;
+  int rc = SQLITE_OK;
+  int i;
+  const int iSavepoint = p->iStatement-1;
+
+  assert( eOp==SAVEPOINT_ROLLBACK || eOp==SAVEPOINT_RELEASE);
+  assert( db->nStatement>0 );
+  assert( p->iStatement==(db->nStatement+db->nSavepoint) );
+
+  for(i=0; i<db->nDb; i++){
+    int rc2 = SQLITE_OK;
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      if( eOp==SAVEPOINT_ROLLBACK ){
+        rc2 = sqlite3BtreeSavepoint(pBt, SAVEPOINT_ROLLBACK, iSavepoint);
+      }
+      if( rc2==SQLITE_OK ){
+        rc2 = sqlite3BtreeSavepoint(pBt, SAVEPOINT_RELEASE, iSavepoint);
+      }
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+  }
+  db->nStatement--;
+  p->iStatement = 0;
+
+  if( rc==SQLITE_OK ){
+    if( eOp==SAVEPOINT_ROLLBACK ){
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_ROLLBACK, iSavepoint);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_RELEASE, iSavepoint);
+    }
+  }
+
+  /* If the statement transaction is being rolled back, also restore the
+  ** database handles deferred constraint counter to the value it had when
+  ** the statement transaction was opened.  */
+  if( eOp==SAVEPOINT_ROLLBACK ){
+    db->nDeferredCons = p->nStmtDefCons;
+    db->nDeferredImmCons = p->nStmtDefImmCons;
+  }
+  return rc;
+}
+SQLITE_PRIVATE int sqlite3VdbeCloseStatement(Vdbe *p, int eOp){
+  if( p->db->nStatement && p->iStatement ){
+    return vdbeCloseStatement(p, eOp);
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** This function is called when a transaction opened by the database
+** handle associated with the VM passed as an argument is about to be
+** committed. If there are outstanding deferred foreign key constraint
+** violations, return SQLITE_ERROR. Otherwise, SQLITE_OK.
+**
+** If there are outstanding FK violations and this function returns
+** SQLITE_ERROR, set the result of the VM to SQLITE_CONSTRAINT_FOREIGNKEY
+** and write an error message to it. Then return SQLITE_ERROR.
+*/
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+SQLITE_PRIVATE int sqlite3VdbeCheckFk(Vdbe *p, int deferred){
+  sqlite3 *db = p->db;
+  if( (deferred && (db->nDeferredCons+db->nDeferredImmCons)>0)
+   || (!deferred && p->nFkConstraint>0)
+  ){
+    p->rc = SQLITE_CONSTRAINT_FOREIGNKEY;
+    p->errorAction = OE_Abort;
+    sqlite3VdbeError(p, "FOREIGN KEY constraint failed");
+    if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)==0 ) return SQLITE_ERROR;
+    return SQLITE_CONSTRAINT_FOREIGNKEY;
+  }
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** This routine is called the when a VDBE tries to halt.  If the VDBE
+** has made changes and is in autocommit mode, then commit those
+** changes.  If a rollback is needed, then do the rollback.
+**
+** This routine is the only way to move the sqlite3eOpenState of a VM from
+** SQLITE_STATE_RUN to SQLITE_STATE_HALT.  It is harmless to
+** call this on a VM that is in the SQLITE_STATE_HALT state.
+**
+** Return an error code.  If the commit could not complete because of
+** lock contention, return SQLITE_BUSY.  If SQLITE_BUSY is returned, it
+** means the close did not happen and needs to be repeated.
+*/
+SQLITE_PRIVATE int sqlite3VdbeHalt(Vdbe *p){
+  int rc;                         /* Used to store transient return codes */
+  sqlite3 *db = p->db;
+
+  /* This function contains the logic that determines if a statement or
+  ** transaction will be committed or rolled back as a result of the
+  ** execution of this virtual machine.
+  **
+  ** If any of the following errors occur:
+  **
+  **     SQLITE_NOMEM
+  **     SQLITE_IOERR
+  **     SQLITE_FULL
+  **     SQLITE_INTERRUPT
+  **
+  ** Then the internal cache might have been left in an inconsistent
+  ** state.  We need to rollback the statement transaction, if there is
+  ** one, or the complete transaction if there is no statement transaction.
+  */
+
+  assert( p->eVdbeState==VDBE_RUN_STATE );
+  if( db->mallocFailed ){
+    p->rc = SQLITE_NOMEM_BKPT;
+  }
+  closeAllCursors(p);
+  checkActiveVdbeCnt(db);
+
+  /* No commit or rollback needed if the program never started or if the
+  ** SQL statement does not read or write a database file.  */
+  if( p->bIsReader ){
+    int mrc;   /* Primary error code from p->rc */
+    int eStatementOp = 0;
+    int isSpecialError;            /* Set to true if a 'special' error */
+
+    /* Lock all btrees used by the statement */
+    sqlite3VdbeEnter(p);
+
+    /* Check for one of the special errors */
+    if( p->rc ){
+      mrc = p->rc & 0xff;
+      isSpecialError = mrc==SQLITE_NOMEM
+                    || mrc==SQLITE_IOERR
+                    || mrc==SQLITE_INTERRUPT
+                    || mrc==SQLITE_FULL;
+    }else{
+      mrc = isSpecialError = 0;
+    }
+    if( isSpecialError ){
+      /* If the query was read-only and the error code is SQLITE_INTERRUPT,
+      ** no rollback is necessary. Otherwise, at least a savepoint
+      ** transaction must be rolled back to restore the database to a
+      ** consistent state.
+      **
+      ** Even if the statement is read-only, it is important to perform
+      ** a statement or transaction rollback operation. If the error
+      ** occurred while writing to the journal, sub-journal or database
+      ** file as part of an effort to free up cache space (see function
+      ** pagerStress() in pager.c), the rollback is required to restore
+      ** the pager to a consistent state.
+      */
+      if( !p->readOnly || mrc!=SQLITE_INTERRUPT ){
+        if( (mrc==SQLITE_NOMEM || mrc==SQLITE_FULL) && p->usesStmtJournal ){
+          eStatementOp = SAVEPOINT_ROLLBACK;
+        }else{
+          /* We are forced to roll back the active transaction. Before doing
+          ** so, abort any other statements this handle currently has active.
+          */
+          sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
+          sqlite3CloseSavepoints(db);
+          db->autoCommit = 1;
+          p->nChange = 0;
+        }
+      }
+    }
+
+    /* Check for immediate foreign key violations. */
+    if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
+      (void)sqlite3VdbeCheckFk(p, 0);
+    }
+
+    /* If the auto-commit flag is set and this is the only active writer
+    ** VM, then we do either a commit or rollback of the current transaction.
+    **
+    ** Note: This block also runs if one of the special errors handled
+    ** above has occurred.
+    */
+    if( !sqlite3VtabInSync(db)
+     && db->autoCommit
+     && db->nVdbeWrite==(p->readOnly==0)
+    ){
+      if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
+        rc = sqlite3VdbeCheckFk(p, 1);
+        if( rc!=SQLITE_OK ){
+          if( NEVER(p->readOnly) ){
+            sqlite3VdbeLeave(p);
+            return SQLITE_ERROR;
+          }
+          rc = SQLITE_CONSTRAINT_FOREIGNKEY;
+        }else if( db->flags & SQLITE_CorruptRdOnly ){
+          rc = SQLITE_CORRUPT;
+          db->flags &= ~SQLITE_CorruptRdOnly;
+        }else{
+          /* The auto-commit flag is true, the vdbe program was successful
+          ** or hit an 'OR FAIL' constraint and there are no deferred foreign
+          ** key constraints to hold up the transaction. This means a commit
+          ** is required. */
+          rc = vdbeCommit(db, p);
+        }
+        if( rc==SQLITE_BUSY && p->readOnly ){
+          sqlite3VdbeLeave(p);
+          return SQLITE_BUSY;
+        }else if( rc!=SQLITE_OK ){
+          sqlite3SystemError(db, rc);
+          p->rc = rc;
+          sqlite3RollbackAll(db, SQLITE_OK);
+          p->nChange = 0;
+        }else{
+          db->nDeferredCons = 0;
+          db->nDeferredImmCons = 0;
+          db->flags &= ~(u64)SQLITE_DeferFKs;
+          sqlite3CommitInternalChanges(db);
+        }
+      }else if( p->rc==SQLITE_SCHEMA && db->nVdbeActive>1 ){
+        p->nChange = 0;
+      }else{
+        sqlite3RollbackAll(db, SQLITE_OK);
+        p->nChange = 0;
+      }
+      db->nStatement = 0;
+    }else if( eStatementOp==0 ){
+      if( p->rc==SQLITE_OK || p->errorAction==OE_Fail ){
+        eStatementOp = SAVEPOINT_RELEASE;
+      }else if( p->errorAction==OE_Abort ){
+        eStatementOp = SAVEPOINT_ROLLBACK;
+      }else{
+        sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
+        sqlite3CloseSavepoints(db);
+        db->autoCommit = 1;
+        p->nChange = 0;
+      }
+    }
+
+    /* If eStatementOp is non-zero, then a statement transaction needs to
+    ** be committed or rolled back. Call sqlite3VdbeCloseStatement() to
+    ** do so. If this operation returns an error, and the current statement
+    ** error code is SQLITE_OK or SQLITE_CONSTRAINT, then promote the
+    ** current statement error code.
+    */
+    if( eStatementOp ){
+      rc = sqlite3VdbeCloseStatement(p, eStatementOp);
+      if( rc ){
+        if( p->rc==SQLITE_OK || (p->rc&0xff)==SQLITE_CONSTRAINT ){
+          p->rc = rc;
+          sqlite3DbFree(db, p->zErrMsg);
+          p->zErrMsg = 0;
+        }
+        sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
+        sqlite3CloseSavepoints(db);
+        db->autoCommit = 1;
+        p->nChange = 0;
+      }
+    }
+
+    /* If this was an INSERT, UPDATE or DELETE and no statement transaction
+    ** has been rolled back, update the database connection change-counter.
+    */
+    if( p->changeCntOn ){
+      if( eStatementOp!=SAVEPOINT_ROLLBACK ){
+        sqlite3VdbeSetChanges(db, p->nChange);
+      }else{
+        sqlite3VdbeSetChanges(db, 0);
+      }
+      p->nChange = 0;
+    }
+
+    /* Release the locks */
+    sqlite3VdbeLeave(p);
+  }
+
+  /* We have successfully halted and closed the VM.  Record this fact. */
+  db->nVdbeActive--;
+  if( !p->readOnly ) db->nVdbeWrite--;
+  if( p->bIsReader ) db->nVdbeRead--;
+  assert( db->nVdbeActive>=db->nVdbeRead );
+  assert( db->nVdbeRead>=db->nVdbeWrite );
+  assert( db->nVdbeWrite>=0 );
+  p->eVdbeState = VDBE_HALT_STATE;
+  checkActiveVdbeCnt(db);
+  if( db->mallocFailed ){
+    p->rc = SQLITE_NOMEM_BKPT;
+  }
+
+  /* If the auto-commit flag is set to true, then any locks that were held
+  ** by connection db have now been released. Call sqlite3ConnectionUnlocked()
+  ** to invoke any required unlock-notify callbacks.
+  */
+  if( db->autoCommit ){
+    sqlite3ConnectionUnlocked(db);
+  }
+
+  assert( db->nVdbeActive>0 || db->autoCommit==0 || db->nStatement==0 );
+  return (p->rc==SQLITE_BUSY ? SQLITE_BUSY : SQLITE_OK);
+}
+
+
+/*
+** Each VDBE holds the result of the most recent sqlite3_step() call
+** in p->rc.  This routine sets that result back to SQLITE_OK.
+*/
+SQLITE_PRIVATE void sqlite3VdbeResetStepResult(Vdbe *p){
+  p->rc = SQLITE_OK;
+}
+
+/*
+** Copy the error code and error message belonging to the VDBE passed
+** as the first argument to its database handle (so that they will be
+** returned by calls to sqlite3_errcode() and sqlite3_errmsg()).
+**
+** This function does not clear the VDBE error code or message, just
+** copies them to the database handle.
+*/
+SQLITE_PRIVATE int sqlite3VdbeTransferError(Vdbe *p){
+  sqlite3 *db = p->db;
+  int rc = p->rc;
+  if( p->zErrMsg ){
+    db->bBenignMalloc++;
+    sqlite3BeginBenignMalloc();
+    if( db->pErr==0 ) db->pErr = sqlite3ValueNew(db);
+    sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, SQLITE_TRANSIENT);
+    sqlite3EndBenignMalloc();
+    db->bBenignMalloc--;
+  }else if( db->pErr ){
+    sqlite3ValueSetNull(db->pErr);
+  }
+  db->errCode = rc;
+  db->errByteOffset = -1;
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_SQLLOG
+/*
+** If an SQLITE_CONFIG_SQLLOG hook is registered and the VM has been run,
+** invoke it.
+*/
+static void vdbeInvokeSqllog(Vdbe *v){
+  if( sqlite3GlobalConfig.xSqllog && v->rc==SQLITE_OK && v->zSql && v->pc>=0 ){
+    char *zExpanded = sqlite3VdbeExpandSql(v, v->zSql);
+    assert( v->db->init.busy==0 );
+    if( zExpanded ){
+      sqlite3GlobalConfig.xSqllog(
+          sqlite3GlobalConfig.pSqllogArg, v->db, zExpanded, 1
+      );
+      sqlite3DbFree(v->db, zExpanded);
+    }
+  }
+}
+#else
+# define vdbeInvokeSqllog(x)
+#endif
+
+/*
+** Clean up a VDBE after execution but do not delete the VDBE just yet.
+** Write any error messages into *pzErrMsg.  Return the result code.
+**
+** After this routine is run, the VDBE should be ready to be executed
+** again.
+**
+** To look at it another way, this routine resets the state of the
+** virtual machine from VDBE_RUN_STATE or VDBE_HALT_STATE back to
+** VDBE_READY_STATE.
+*/
+SQLITE_PRIVATE int sqlite3VdbeReset(Vdbe *p){
+#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
+  int i;
+#endif
+
+  sqlite3 *db;
+  db = p->db;
+
+  /* If the VM did not run to completion or if it encountered an
+  ** error, then it might not have been halted properly.  So halt
+  ** it now.
+  */
+  if( p->eVdbeState==VDBE_RUN_STATE ) sqlite3VdbeHalt(p);
+
+  /* If the VDBE has been run even partially, then transfer the error code
+  ** and error message from the VDBE into the main database structure.  But
+  ** if the VDBE has just been set to run but has not actually executed any
+  ** instructions yet, leave the main database error information unchanged.
+  */
+  if( p->pc>=0 ){
+    vdbeInvokeSqllog(p);
+    if( db->pErr || p->zErrMsg ){
+      sqlite3VdbeTransferError(p);
+    }else{
+      db->errCode = p->rc;
+    }
+  }
+
+  /* Reset register contents and reclaim error message memory.
+  */
+#ifdef SQLITE_DEBUG
+  /* Execute assert() statements to ensure that the Vdbe.apCsr[] and
+  ** Vdbe.aMem[] arrays have already been cleaned up.  */
+  if( p->apCsr ) for(i=0; i<p->nCursor; i++) assert( p->apCsr[i]==0 );
+  if( p->aMem ){
+    for(i=0; i<p->nMem; i++) assert( p->aMem[i].flags==MEM_Undefined );
+  }
+#endif
+  if( p->zErrMsg ){
+    sqlite3DbFree(db, p->zErrMsg);
+    p->zErrMsg = 0;
+  }
+  p->pResultRow = 0;
+#ifdef SQLITE_DEBUG
+  p->nWrite = 0;
+#endif
+
+  /* Save profiling information from this VDBE run.
+  */
+#ifdef VDBE_PROFILE
+  {
+    FILE *out = fopen("vdbe_profile.out", "a");
+    if( out ){
+      fprintf(out, "---- ");
+      for(i=0; i<p->nOp; i++){
+        fprintf(out, "%02x", p->aOp[i].opcode);
+      }
+      fprintf(out, "\n");
+      if( p->zSql ){
+        char c, pc = 0;
+        fprintf(out, "-- ");
+        for(i=0; (c = p->zSql[i])!=0; i++){
+          if( pc=='\n' ) fprintf(out, "-- ");
+          putc(c, out);
+          pc = c;
+        }
+        if( pc!='\n' ) fprintf(out, "\n");
+      }
+      for(i=0; i<p->nOp; i++){
+        char zHdr[100];
+        i64 cnt = p->aOp[i].nExec;
+        i64 cycles = p->aOp[i].nCycle;
+        sqlite3_snprintf(sizeof(zHdr), zHdr, "%6u %12llu %8llu ",
+           cnt,
+           cycles,
+           cnt>0 ? cycles/cnt : 0
+        );
+        fprintf(out, "%s", zHdr);
+        sqlite3VdbePrintOp(out, i, &p->aOp[i]);
+      }
+      fclose(out);
+    }
+  }
+#endif
+  return p->rc & db->errMask;
+}
+
+/*
+** Clean up and delete a VDBE after execution.  Return an integer which is
+** the result code.  Write any error message text into *pzErrMsg.
+*/
+SQLITE_PRIVATE int sqlite3VdbeFinalize(Vdbe *p){
+  int rc = SQLITE_OK;
+  assert( VDBE_RUN_STATE>VDBE_READY_STATE );
+  assert( VDBE_HALT_STATE>VDBE_READY_STATE );
+  assert( VDBE_INIT_STATE<VDBE_READY_STATE );
+  if( p->eVdbeState>=VDBE_READY_STATE ){
+    rc = sqlite3VdbeReset(p);
+    assert( (rc & p->db->errMask)==rc );
+  }
+  sqlite3VdbeDelete(p);
+  return rc;
+}
+
+/*
+** If parameter iOp is less than zero, then invoke the destructor for
+** all auxiliary data pointers currently cached by the VM passed as
+** the first argument.
+**
+** Or, if iOp is greater than or equal to zero, then the destructor is
+** only invoked for those auxiliary data pointers created by the user
+** function invoked by the OP_Function opcode at instruction iOp of
+** VM pVdbe, and only then if:
+**
+**    * the associated function parameter is the 32nd or later (counting
+**      from left to right), or
+**
+**    * the corresponding bit in argument mask is clear (where the first
+**      function parameter corresponds to bit 0 etc.).
+*/
+SQLITE_PRIVATE void sqlite3VdbeDeleteAuxData(sqlite3 *db, AuxData **pp, int iOp, int mask){
+  while( *pp ){
+    AuxData *pAux = *pp;
+    if( (iOp<0)
+     || (pAux->iAuxOp==iOp
+          && pAux->iAuxArg>=0
+          && (pAux->iAuxArg>31 || !(mask & MASKBIT32(pAux->iAuxArg))))
+    ){
+      testcase( pAux->iAuxArg==31 );
+      if( pAux->xDeleteAux ){
+        pAux->xDeleteAux(pAux->pAux);
+      }
+      *pp = pAux->pNextAux;
+      sqlite3DbFree(db, pAux);
+    }else{
+      pp= &pAux->pNextAux;
+    }
+  }
+}
+
+/*
+** Free all memory associated with the Vdbe passed as the second argument,
+** except for object itself, which is preserved.
+**
+** The difference between this function and sqlite3VdbeDelete() is that
+** VdbeDelete() also unlinks the Vdbe from the list of VMs associated with
+** the database connection and frees the object itself.
+*/
+static void sqlite3VdbeClearObject(sqlite3 *db, Vdbe *p){
+  SubProgram *pSub, *pNext;
+  assert( db!=0 );
+  assert( p->db==0 || p->db==db );
+  if( p->aColName ){
+    releaseMemArray(p->aColName, p->nResAlloc*COLNAME_N);
+    sqlite3DbNNFreeNN(db, p->aColName);
+  }
+  for(pSub=p->pProgram; pSub; pSub=pNext){
+    pNext = pSub->pNext;
+    vdbeFreeOpArray(db, pSub->aOp, pSub->nOp);
+    sqlite3DbFree(db, pSub);
+  }
+  if( p->eVdbeState!=VDBE_INIT_STATE ){
+    releaseMemArray(p->aVar, p->nVar);
+    if( p->pVList ) sqlite3DbNNFreeNN(db, p->pVList);
+    if( p->pFree ) sqlite3DbNNFreeNN(db, p->pFree);
+  }
+  vdbeFreeOpArray(db, p->aOp, p->nOp);
+  if( p->zSql ) sqlite3DbNNFreeNN(db, p->zSql);
+#ifdef SQLITE_ENABLE_NORMALIZE
+  sqlite3DbFree(db, p->zNormSql);
+  {
+    DblquoteStr *pThis, *pNxt;
+    for(pThis=p->pDblStr; pThis; pThis=pNxt){
+      pNxt = pThis->pNextStr;
+      sqlite3DbFree(db, pThis);
+    }
+  }
+#endif
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  {
+    int i;
+    for(i=0; i<p->nScan; i++){
+      sqlite3DbFree(db, p->aScan[i].zName);
+    }
+    sqlite3DbFree(db, p->aScan);
+  }
+#endif
+}
+
+/*
+** Delete an entire VDBE.
+*/
+SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe *p){
+  sqlite3 *db;
+
+  assert( p!=0 );
+  db = p->db;
+  assert( db!=0 );
+  assert( sqlite3_mutex_held(db->mutex) );
+  sqlite3VdbeClearObject(db, p);
+  if( db->pnBytesFreed==0 ){
+    assert( p->ppVPrev!=0 );
+    *p->ppVPrev = p->pVNext;
+    if( p->pVNext ){
+      p->pVNext->ppVPrev = p->ppVPrev;
+    }
+  }
+  sqlite3DbNNFreeNN(db, p);
+}
+
+/*
+** The cursor "p" has a pending seek operation that has not yet been
+** carried out.  Seek the cursor now.  If an error occurs, return
+** the appropriate error code.
+*/
+SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeFinishMoveto(VdbeCursor *p){
+  int res, rc;
+#ifdef SQLITE_TEST
+  extern int sqlite3_search_count;
+#endif
+  assert( p->deferredMoveto );
+  assert( p->isTable );
+  assert( p->eCurType==CURTYPE_BTREE );
+  rc = sqlite3BtreeTableMoveto(p->uc.pCursor, p->movetoTarget, 0, &res);
+  if( rc ) return rc;
+  if( res!=0 ) return SQLITE_CORRUPT_BKPT;
+#ifdef SQLITE_TEST
+  sqlite3_search_count++;
+#endif
+  p->deferredMoveto = 0;
+  p->cacheStatus = CACHE_STALE;
+  return SQLITE_OK;
+}
+
+/*
+** Something has moved cursor "p" out of place.  Maybe the row it was
+** pointed to was deleted out from under it.  Or maybe the btree was
+** rebalanced.  Whatever the cause, try to restore "p" to the place it
+** is supposed to be pointing.  If the row was deleted out from under the
+** cursor, set the cursor to point to a NULL row.
+*/
+SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeHandleMovedCursor(VdbeCursor *p){
+  int isDifferentRow, rc;
+  assert( p->eCurType==CURTYPE_BTREE );
+  assert( p->uc.pCursor!=0 );
+  assert( sqlite3BtreeCursorHasMoved(p->uc.pCursor) );
+  rc = sqlite3BtreeCursorRestore(p->uc.pCursor, &isDifferentRow);
+  p->cacheStatus = CACHE_STALE;
+  if( isDifferentRow ) p->nullRow = 1;
+  return rc;
+}
+
+/*
+** Check to ensure that the cursor is valid.  Restore the cursor
+** if need be.  Return any I/O error from the restore operation.
+*/
+SQLITE_PRIVATE int sqlite3VdbeCursorRestore(VdbeCursor *p){
+  assert( p->eCurType==CURTYPE_BTREE || IsNullCursor(p) );
+  if( sqlite3BtreeCursorHasMoved(p->uc.pCursor) ){
+    return sqlite3VdbeHandleMovedCursor(p);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The following functions:
+**
+** sqlite3VdbeSerialType()
+** sqlite3VdbeSerialTypeLen()
+** sqlite3VdbeSerialLen()
+** sqlite3VdbeSerialPut()  <--- in-lined into OP_MakeRecord as of 2022-04-02
+** sqlite3VdbeSerialGet()
+**
+** encapsulate the code that serializes values for storage in SQLite
+** data and index records. Each serialized value consists of a
+** 'serial-type' and a blob of data. The serial type is an 8-byte unsigned
+** integer, stored as a varint.
+**
+** In an SQLite index record, the serial type is stored directly before
+** the blob of data that it corresponds to. In a table record, all serial
+** types are stored at the start of the record, and the blobs of data at
+** the end. Hence these functions allow the caller to handle the
+** serial-type and data blob separately.
+**
+** The following table describes the various storage classes for data:
+**
+**   serial type        bytes of data      type
+**   --------------     ---------------    ---------------
+**      0                     0            NULL
+**      1                     1            signed integer
+**      2                     2            signed integer
+**      3                     3            signed integer
+**      4                     4            signed integer
+**      5                     6            signed integer
+**      6                     8            signed integer
+**      7                     8            IEEE float
+**      8                     0            Integer constant 0
+**      9                     0            Integer constant 1
+**     10,11                               reserved for expansion
+**    N>=12 and even       (N-12)/2        BLOB
+**    N>=13 and odd        (N-13)/2        text
+**
+** The 8 and 9 types were added in 3.3.0, file format 4.  Prior versions
+** of SQLite will not understand those serial types.
+*/
+
+#if 0 /* Inlined into the OP_MakeRecord opcode */
+/*
+** Return the serial-type for the value stored in pMem.
+**
+** This routine might convert a large MEM_IntReal value into MEM_Real.
+**
+** 2019-07-11:  The primary user of this subroutine was the OP_MakeRecord
+** opcode in the byte-code engine.  But by moving this routine in-line, we
+** can omit some redundant tests and make that opcode a lot faster.  So
+** this routine is now only used by the STAT3 logic and STAT3 support has
+** ended.  The code is kept here for historical reference only.
+*/
+SQLITE_PRIVATE u32 sqlite3VdbeSerialType(Mem *pMem, int file_format, u32 *pLen){
+  int flags = pMem->flags;
+  u32 n;
+
+  assert( pLen!=0 );
+  if( flags&MEM_Null ){
+    *pLen = 0;
+    return 0;
+  }
+  if( flags&(MEM_Int|MEM_IntReal) ){
+    /* Figure out whether to use 1, 2, 4, 6 or 8 bytes. */
+#   define MAX_6BYTE ((((i64)0x00008000)<<32)-1)
+    i64 i = pMem->u.i;
+    u64 u;
+    testcase( flags & MEM_Int );
+    testcase( flags & MEM_IntReal );
+    if( i<0 ){
+      u = ~i;
+    }else{
+      u = i;
+    }
+    if( u<=127 ){
+      if( (i&1)==i && file_format>=4 ){
+        *pLen = 0;
+        return 8+(u32)u;
+      }else{
+        *pLen = 1;
+        return 1;
+      }
+    }
+    if( u<=32767 ){ *pLen = 2; return 2; }
+    if( u<=8388607 ){ *pLen = 3; return 3; }
+    if( u<=2147483647 ){ *pLen = 4; return 4; }
+    if( u<=MAX_6BYTE ){ *pLen = 6; return 5; }
+    *pLen = 8;
+    if( flags&MEM_IntReal ){
+      /* If the value is IntReal and is going to take up 8 bytes to store
+      ** as an integer, then we might as well make it an 8-byte floating
+      ** point value */
+      pMem->u.r = (double)pMem->u.i;
+      pMem->flags &= ~MEM_IntReal;
+      pMem->flags |= MEM_Real;
+      return 7;
+    }
+    return 6;
+  }
+  if( flags&MEM_Real ){
+    *pLen = 8;
+    return 7;
+  }
+  assert( pMem->db->mallocFailed || flags&(MEM_Str|MEM_Blob) );
+  assert( pMem->n>=0 );
+  n = (u32)pMem->n;
+  if( flags & MEM_Zero ){
+    n += pMem->u.nZero;
+  }
+  *pLen = n;
+  return ((n*2) + 12 + ((flags&MEM_Str)!=0));
+}
+#endif /* inlined into OP_MakeRecord */
+
+/*
+** The sizes for serial types less than 128
+*/
+SQLITE_PRIVATE const u8 sqlite3SmallTypeSizes[128] = {
+        /*  0   1   2   3   4   5   6   7   8   9 */
+/*   0 */   0,  1,  2,  3,  4,  6,  8,  8,  0,  0,
+/*  10 */   0,  0,  0,  0,  1,  1,  2,  2,  3,  3,
+/*  20 */   4,  4,  5,  5,  6,  6,  7,  7,  8,  8,
+/*  30 */   9,  9, 10, 10, 11, 11, 12, 12, 13, 13,
+/*  40 */  14, 14, 15, 15, 16, 16, 17, 17, 18, 18,
+/*  50 */  19, 19, 20, 20, 21, 21, 22, 22, 23, 23,
+/*  60 */  24, 24, 25, 25, 26, 26, 27, 27, 28, 28,
+/*  70 */  29, 29, 30, 30, 31, 31, 32, 32, 33, 33,
+/*  80 */  34, 34, 35, 35, 36, 36, 37, 37, 38, 38,
+/*  90 */  39, 39, 40, 40, 41, 41, 42, 42, 43, 43,
+/* 100 */  44, 44, 45, 45, 46, 46, 47, 47, 48, 48,
+/* 110 */  49, 49, 50, 50, 51, 51, 52, 52, 53, 53,
+/* 120 */  54, 54, 55, 55, 56, 56, 57, 57
+};
+
+/*
+** Return the length of the data corresponding to the supplied serial-type.
+*/
+SQLITE_PRIVATE u32 sqlite3VdbeSerialTypeLen(u32 serial_type){
+  if( serial_type>=128 ){
+    return (serial_type-12)/2;
+  }else{
+    assert( serial_type<12
+            || sqlite3SmallTypeSizes[serial_type]==(serial_type - 12)/2 );
+    return sqlite3SmallTypeSizes[serial_type];
+  }
+}
+SQLITE_PRIVATE u8 sqlite3VdbeOneByteSerialTypeLen(u8 serial_type){
+  assert( serial_type<128 );
+  return sqlite3SmallTypeSizes[serial_type];
+}
+
+/*
+** If we are on an architecture with mixed-endian floating
+** points (ex: ARM7) then swap the lower 4 bytes with the
+** upper 4 bytes.  Return the result.
+**
+** For most architectures, this is a no-op.
+**
+** (later):  It is reported to me that the mixed-endian problem
+** on ARM7 is an issue with GCC, not with the ARM7 chip.  It seems
+** that early versions of GCC stored the two words of a 64-bit
+** float in the wrong order.  And that error has been propagated
+** ever since.  The blame is not necessarily with GCC, though.
+** GCC might have just copying the problem from a prior compiler.
+** I am also told that newer versions of GCC that follow a different
+** ABI get the byte order right.
+**
+** Developers using SQLite on an ARM7 should compile and run their
+** application using -DSQLITE_DEBUG=1 at least once.  With DEBUG
+** enabled, some asserts below will ensure that the byte order of
+** floating point values is correct.
+**
+** (2007-08-30)  Frank van Vugt has studied this problem closely
+** and has send his findings to the SQLite developers.  Frank
+** writes that some Linux kernels offer floating point hardware
+** emulation that uses only 32-bit mantissas instead of a full
+** 48-bits as required by the IEEE standard.  (This is the
+** CONFIG_FPE_FASTFPE option.)  On such systems, floating point
+** byte swapping becomes very complicated.  To avoid problems,
+** the necessary byte swapping is carried out using a 64-bit integer
+** rather than a 64-bit float.  Frank assures us that the code here
+** works for him.  We, the developers, have no way to independently
+** verify this, but Frank seems to know what he is talking about
+** so we trust him.
+*/
+#ifdef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
+SQLITE_PRIVATE u64 sqlite3FloatSwap(u64 in){
+  union {
+    u64 r;
+    u32 i[2];
+  } u;
+  u32 t;
+
+  u.r = in;
+  t = u.i[0];
+  u.i[0] = u.i[1];
+  u.i[1] = t;
+  return u.r;
+}
+#endif /* SQLITE_MIXED_ENDIAN_64BIT_FLOAT */
+
+
+/* Input "x" is a sequence of unsigned characters that represent a
+** big-endian integer.  Return the equivalent native integer
+*/
+#define ONE_BYTE_INT(x)    ((i8)(x)[0])
+#define TWO_BYTE_INT(x)    (256*(i8)((x)[0])|(x)[1])
+#define THREE_BYTE_INT(x)  (65536*(i8)((x)[0])|((x)[1]<<8)|(x)[2])
+#define FOUR_BYTE_UINT(x)  (((u32)(x)[0]<<24)|((x)[1]<<16)|((x)[2]<<8)|(x)[3])
+#define FOUR_BYTE_INT(x) (16777216*(i8)((x)[0])|((x)[1]<<16)|((x)[2]<<8)|(x)[3])
+
+/*
+** Deserialize the data blob pointed to by buf as serial type serial_type
+** and store the result in pMem.
+**
+** This function is implemented as two separate routines for performance.
+** The few cases that require local variables are broken out into a separate
+** routine so that in most cases the overhead of moving the stack pointer
+** is avoided.
+*/
+static void serialGet(
+  const unsigned char *buf,     /* Buffer to deserialize from */
+  u32 serial_type,              /* Serial type to deserialize */
+  Mem *pMem                     /* Memory cell to write value into */
+){
+  u64 x = FOUR_BYTE_UINT(buf);
+  u32 y = FOUR_BYTE_UINT(buf+4);
+  x = (x<<32) + y;
+  if( serial_type==6 ){
+    /* EVIDENCE-OF: R-29851-52272 Value is a big-endian 64-bit
+    ** twos-complement integer. */
+    pMem->u.i = *(i64*)&x;
+    pMem->flags = MEM_Int;
+    testcase( pMem->u.i<0 );
+  }else{
+    /* EVIDENCE-OF: R-57343-49114 Value is a big-endian IEEE 754-2008 64-bit
+    ** floating point number. */
+#if !defined(NDEBUG) && !defined(SQLITE_OMIT_FLOATING_POINT)
+    /* Verify that integers and floating point values use the same
+    ** byte order.  Or, that if SQLITE_MIXED_ENDIAN_64BIT_FLOAT is
+    ** defined that 64-bit floating point values really are mixed
+    ** endian.
+    */
+    static const u64 t1 = ((u64)0x3ff00000)<<32;
+    static const double r1 = 1.0;
+    u64 t2 = t1;
+    swapMixedEndianFloat(t2);
+    assert( sizeof(r1)==sizeof(t2) && memcmp(&r1, &t2, sizeof(r1))==0 );
+#endif
+    assert( sizeof(x)==8 && sizeof(pMem->u.r)==8 );
+    swapMixedEndianFloat(x);
+    memcpy(&pMem->u.r, &x, sizeof(x));
+    pMem->flags = IsNaN(x) ? MEM_Null : MEM_Real;
+  }
+}
+static int serialGet7(
+  const unsigned char *buf,     /* Buffer to deserialize from */
+  Mem *pMem                     /* Memory cell to write value into */
+){
+  u64 x = FOUR_BYTE_UINT(buf);
+  u32 y = FOUR_BYTE_UINT(buf+4);
+  x = (x<<32) + y;
+  assert( sizeof(x)==8 && sizeof(pMem->u.r)==8 );
+  swapMixedEndianFloat(x);
+  memcpy(&pMem->u.r, &x, sizeof(x));
+  if( IsNaN(x) ){
+    pMem->flags = MEM_Null;
+    return 1;
+  }
+  pMem->flags = MEM_Real;
+  return 0;
+}
+SQLITE_PRIVATE void sqlite3VdbeSerialGet(
+  const unsigned char *buf,     /* Buffer to deserialize from */
+  u32 serial_type,              /* Serial type to deserialize */
+  Mem *pMem                     /* Memory cell to write value into */
+){
+  switch( serial_type ){
+    case 10: { /* Internal use only: NULL with virtual table
+               ** UPDATE no-change flag set */
+      pMem->flags = MEM_Null|MEM_Zero;
+      pMem->n = 0;
+      pMem->u.nZero = 0;
+      return;
+    }
+    case 11:   /* Reserved for future use */
+    case 0: {  /* Null */
+      /* EVIDENCE-OF: R-24078-09375 Value is a NULL. */
+      pMem->flags = MEM_Null;
+      return;
+    }
+    case 1: {
+      /* EVIDENCE-OF: R-44885-25196 Value is an 8-bit twos-complement
+      ** integer. */
+      pMem->u.i = ONE_BYTE_INT(buf);
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 2: { /* 2-byte signed integer */
+      /* EVIDENCE-OF: R-49794-35026 Value is a big-endian 16-bit
+      ** twos-complement integer. */
+      pMem->u.i = TWO_BYTE_INT(buf);
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 3: { /* 3-byte signed integer */
+      /* EVIDENCE-OF: R-37839-54301 Value is a big-endian 24-bit
+      ** twos-complement integer. */
+      pMem->u.i = THREE_BYTE_INT(buf);
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 4: { /* 4-byte signed integer */
+      /* EVIDENCE-OF: R-01849-26079 Value is a big-endian 32-bit
+      ** twos-complement integer. */
+      pMem->u.i = FOUR_BYTE_INT(buf);
+#ifdef __HP_cc
+      /* Work around a sign-extension bug in the HP compiler for HP/UX */
+      if( buf[0]&0x80 ) pMem->u.i |= 0xffffffff80000000LL;
+#endif
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 5: { /* 6-byte signed integer */
+      /* EVIDENCE-OF: R-50385-09674 Value is a big-endian 48-bit
+      ** twos-complement integer. */
+      pMem->u.i = FOUR_BYTE_UINT(buf+2) + (((i64)1)<<32)*TWO_BYTE_INT(buf);
+      pMem->flags = MEM_Int;
+      testcase( pMem->u.i<0 );
+      return;
+    }
+    case 6:   /* 8-byte signed integer */
+    case 7: { /* IEEE floating point */
+      /* These use local variables, so do them in a separate routine
+      ** to avoid having to move the frame pointer in the common case */
+      serialGet(buf,serial_type,pMem);
+      return;
+    }
+    case 8:    /* Integer 0 */
+    case 9: {  /* Integer 1 */
+      /* EVIDENCE-OF: R-12976-22893 Value is the integer 0. */
+      /* EVIDENCE-OF: R-18143-12121 Value is the integer 1. */
+      pMem->u.i = serial_type-8;
+      pMem->flags = MEM_Int;
+      return;
+    }
+    default: {
+      /* EVIDENCE-OF: R-14606-31564 Value is a BLOB that is (N-12)/2 bytes in
+      ** length.
+      ** EVIDENCE-OF: R-28401-00140 Value is a string in the text encoding and
+      ** (N-13)/2 bytes in length. */
+      static const u16 aFlag[] = { MEM_Blob|MEM_Ephem, MEM_Str|MEM_Ephem };
+      pMem->z = (char *)buf;
+      pMem->n = (serial_type-12)/2;
+      pMem->flags = aFlag[serial_type&1];
+      return;
+    }
+  }
+  return;
+}
+/*
+** This routine is used to allocate sufficient space for an UnpackedRecord
+** structure large enough to be used with sqlite3VdbeRecordUnpack() if
+** the first argument is a pointer to KeyInfo structure pKeyInfo.
+**
+** The space is either allocated using sqlite3DbMallocRaw() or from within
+** the unaligned buffer passed via the second and third arguments (presumably
+** stack space). If the former, then *ppFree is set to a pointer that should
+** be eventually freed by the caller using sqlite3DbFree(). Or, if the
+** allocation comes from the pSpace/szSpace buffer, *ppFree is set to NULL
+** before returning.
+**
+** If an OOM error occurs, NULL is returned.
+*/
+SQLITE_PRIVATE UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(
+  KeyInfo *pKeyInfo               /* Description of the record */
+){
+  UnpackedRecord *p;              /* Unpacked record to return */
+  int nByte;                      /* Number of bytes required for *p */
+  nByte = ROUND8P(sizeof(UnpackedRecord)) + sizeof(Mem)*(pKeyInfo->nKeyField+1);
+  p = (UnpackedRecord *)sqlite3DbMallocRaw(pKeyInfo->db, nByte);
+  if( !p ) return 0;
+  p->aMem = (Mem*)&((char*)p)[ROUND8P(sizeof(UnpackedRecord))];
+  assert( pKeyInfo->aSortFlags!=0 );
+  p->pKeyInfo = pKeyInfo;
+  p->nField = pKeyInfo->nKeyField + 1;
+  return p;
+}
+
+/*
+** Given the nKey-byte encoding of a record in pKey[], populate the
+** UnpackedRecord structure indicated by the fourth argument with the
+** contents of the decoded record.
+*/
+SQLITE_PRIVATE void sqlite3VdbeRecordUnpack(
+  KeyInfo *pKeyInfo,     /* Information about the record format */
+  int nKey,              /* Size of the binary record */
+  const void *pKey,      /* The binary record */
+  UnpackedRecord *p      /* Populate this structure before returning. */
+){
+  const unsigned char *aKey = (const unsigned char *)pKey;
+  u32 d;
+  u32 idx;                        /* Offset in aKey[] to read from */
+  u16 u;                          /* Unsigned loop counter */
+  u32 szHdr;
+  Mem *pMem = p->aMem;
+
+  p->default_rc = 0;
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+  idx = getVarint32(aKey, szHdr);
+  d = szHdr;
+  u = 0;
+  while( idx<szHdr && d<=(u32)nKey ){
+    u32 serial_type;
+
+    idx += getVarint32(&aKey[idx], serial_type);
+    pMem->enc = pKeyInfo->enc;
+    pMem->db = pKeyInfo->db;
+    /* pMem->flags = 0; // sqlite3VdbeSerialGet() will set this for us */
+    pMem->szMalloc = 0;
+    pMem->z = 0;
+    sqlite3VdbeSerialGet(&aKey[d], serial_type, pMem);
+    d += sqlite3VdbeSerialTypeLen(serial_type);
+    pMem++;
+    if( (++u)>=p->nField ) break;
+  }
+  if( d>(u32)nKey && u ){
+    assert( CORRUPT_DB );
+    /* In a corrupt record entry, the last pMem might have been set up using
+    ** uninitialized memory. Overwrite its value with NULL, to prevent
+    ** warnings from MSAN. */
+    sqlite3VdbeMemSetNull(pMem-1);
+  }
+  assert( u<=pKeyInfo->nKeyField + 1 );
+  p->nField = u;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** This function compares two index or table record keys in the same way
+** as the sqlite3VdbeRecordCompare() routine. Unlike VdbeRecordCompare(),
+** this function deserializes and compares values using the
+** sqlite3VdbeSerialGet() and sqlite3MemCompare() functions. It is used
+** in assert() statements to ensure that the optimized code in
+** sqlite3VdbeRecordCompare() returns results with these two primitives.
+**
+** Return true if the result of comparison is equivalent to desiredResult.
+** Return false if there is a disagreement.
+*/
+static int vdbeRecordCompareDebug(
+  int nKey1, const void *pKey1, /* Left key */
+  const UnpackedRecord *pPKey2, /* Right key */
+  int desiredResult             /* Correct answer */
+){
+  u32 d1;            /* Offset into aKey[] of next data element */
+  u32 idx1;          /* Offset into aKey[] of next header element */
+  u32 szHdr1;        /* Number of bytes in header */
+  int i = 0;
+  int rc = 0;
+  const unsigned char *aKey1 = (const unsigned char *)pKey1;
+  KeyInfo *pKeyInfo;
+  Mem mem1;
+
+  pKeyInfo = pPKey2->pKeyInfo;
+  if( pKeyInfo->db==0 ) return 1;
+  mem1.enc = pKeyInfo->enc;
+  mem1.db = pKeyInfo->db;
+  /* mem1.flags = 0;  // Will be initialized by sqlite3VdbeSerialGet() */
+  VVA_ONLY( mem1.szMalloc = 0; ) /* Only needed by assert() statements */
+
+  /* Compilers may complain that mem1.u.i is potentially uninitialized.
+  ** We could initialize it, as shown here, to silence those complaints.
+  ** But in fact, mem1.u.i will never actually be used uninitialized, and doing
+  ** the unnecessary initialization has a measurable negative performance
+  ** impact, since this routine is a very high runner.  And so, we choose
+  ** to ignore the compiler warnings and leave this variable uninitialized.
+  */
+  /*  mem1.u.i = 0;  // not needed, here to silence compiler warning */
+
+  idx1 = getVarint32(aKey1, szHdr1);
+  if( szHdr1>98307 ) return SQLITE_CORRUPT;
+  d1 = szHdr1;
+  assert( pKeyInfo->nAllField>=pPKey2->nField || CORRUPT_DB );
+  assert( pKeyInfo->aSortFlags!=0 );
+  assert( pKeyInfo->nKeyField>0 );
+  assert( idx1<=szHdr1 || CORRUPT_DB );
+  do{
+    u32 serial_type1;
+
+    /* Read the serial types for the next element in each key. */
+    idx1 += getVarint32( aKey1+idx1, serial_type1 );
+
+    /* Verify that there is enough key space remaining to avoid
+    ** a buffer overread.  The "d1+serial_type1+2" subexpression will
+    ** always be greater than or equal to the amount of required key space.
+    ** Use that approximation to avoid the more expensive call to
+    ** sqlite3VdbeSerialTypeLen() in the common case.
+    */
+    if( d1+(u64)serial_type1+2>(u64)nKey1
+     && d1+(u64)sqlite3VdbeSerialTypeLen(serial_type1)>(u64)nKey1
+    ){
+      if( serial_type1>=1
+       && serial_type1<=7
+       && d1+(u64)sqlite3VdbeSerialTypeLen(serial_type1)<=(u64)nKey1+8
+       && CORRUPT_DB
+      ){
+        return 1;  /* corrupt record not detected by
+                   ** sqlite3VdbeRecordCompareWithSkip().  Return true
+                   ** to avoid firing the assert() */
+      }
+      break;
+    }
+
+    /* Extract the values to be compared.
+    */
+    sqlite3VdbeSerialGet(&aKey1[d1], serial_type1, &mem1);
+    d1 += sqlite3VdbeSerialTypeLen(serial_type1);
+
+    /* Do the comparison
+    */
+    rc = sqlite3MemCompare(&mem1, &pPKey2->aMem[i],
+                           pKeyInfo->nAllField>i ? pKeyInfo->aColl[i] : 0);
+    if( rc!=0 ){
+      assert( mem1.szMalloc==0 );  /* See comment below */
+      if( (pKeyInfo->aSortFlags[i] & KEYINFO_ORDER_BIGNULL)
+       && ((mem1.flags & MEM_Null) || (pPKey2->aMem[i].flags & MEM_Null))
+      ){
+        rc = -rc;
+      }
+      if( pKeyInfo->aSortFlags[i] & KEYINFO_ORDER_DESC ){
+        rc = -rc;  /* Invert the result for DESC sort order. */
+      }
+      goto debugCompareEnd;
+    }
+    i++;
+  }while( idx1<szHdr1 && i<pPKey2->nField );
+
+  /* No memory allocation is ever used on mem1.  Prove this using
+  ** the following assert().  If the assert() fails, it indicates a
+  ** memory leak and a need to call sqlite3VdbeMemRelease(&mem1).
+  */
+  assert( mem1.szMalloc==0 );
+
+  /* rc==0 here means that one of the keys ran out of fields and
+  ** all the fields up to that point were equal. Return the default_rc
+  ** value.  */
+  rc = pPKey2->default_rc;
+
+debugCompareEnd:
+  if( desiredResult==0 && rc==0 ) return 1;
+  if( desiredResult<0 && rc<0 ) return 1;
+  if( desiredResult>0 && rc>0 ) return 1;
+  if( CORRUPT_DB ) return 1;
+  if( pKeyInfo->db->mallocFailed ) return 1;
+  return 0;
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Count the number of fields (a.k.a. columns) in the record given by
+** pKey,nKey.  The verify that this count is less than or equal to the
+** limit given by pKeyInfo->nAllField.
+**
+** If this constraint is not satisfied, it means that the high-speed
+** vdbeRecordCompareInt() and vdbeRecordCompareString() routines will
+** not work correctly.  If this assert() ever fires, it probably means
+** that the KeyInfo.nKeyField or KeyInfo.nAllField values were computed
+** incorrectly.
+*/
+static void vdbeAssertFieldCountWithinLimits(
+  int nKey, const void *pKey,   /* The record to verify */
+  const KeyInfo *pKeyInfo       /* Compare size with this KeyInfo */
+){
+  int nField = 0;
+  u32 szHdr;
+  u32 idx;
+  u32 notUsed;
+  const unsigned char *aKey = (const unsigned char*)pKey;
+
+  if( CORRUPT_DB ) return;
+  idx = getVarint32(aKey, szHdr);
+  assert( nKey>=0 );
+  assert( szHdr<=(u32)nKey );
+  while( idx<szHdr ){
+    idx += getVarint32(aKey+idx, notUsed);
+    nField++;
+  }
+  assert( nField <= pKeyInfo->nAllField );
+}
+#else
+# define vdbeAssertFieldCountWithinLimits(A,B,C)
+#endif
+
+/*
+** Both *pMem1 and *pMem2 contain string values. Compare the two values
+** using the collation sequence pColl. As usual, return a negative , zero
+** or positive value if *pMem1 is less than, equal to or greater than
+** *pMem2, respectively. Similar in spirit to "rc = (*pMem1) - (*pMem2);".
+*/
+static int vdbeCompareMemString(
+  const Mem *pMem1,
+  const Mem *pMem2,
+  const CollSeq *pColl,
+  u8 *prcErr                      /* If an OOM occurs, set to SQLITE_NOMEM */
+){
+  if( pMem1->enc==pColl->enc ){
+    /* The strings are already in the correct encoding.  Call the
+     ** comparison function directly */
+    return pColl->xCmp(pColl->pUser,pMem1->n,pMem1->z,pMem2->n,pMem2->z);
+  }else{
+    int rc;
+    const void *v1, *v2;
+    Mem c1;
+    Mem c2;
+    sqlite3VdbeMemInit(&c1, pMem1->db, MEM_Null);
+    sqlite3VdbeMemInit(&c2, pMem1->db, MEM_Null);
+    sqlite3VdbeMemShallowCopy(&c1, pMem1, MEM_Ephem);
+    sqlite3VdbeMemShallowCopy(&c2, pMem2, MEM_Ephem);
+    v1 = sqlite3ValueText((sqlite3_value*)&c1, pColl->enc);
+    v2 = sqlite3ValueText((sqlite3_value*)&c2, pColl->enc);
+    if( (v1==0 || v2==0) ){
+      if( prcErr ) *prcErr = SQLITE_NOMEM_BKPT;
+      rc = 0;
+    }else{
+      rc = pColl->xCmp(pColl->pUser, c1.n, v1, c2.n, v2);
+    }
+    sqlite3VdbeMemReleaseMalloc(&c1);
+    sqlite3VdbeMemReleaseMalloc(&c2);
+    return rc;
+  }
+}
+
+/*
+** The input pBlob is guaranteed to be a Blob that is not marked
+** with MEM_Zero.  Return true if it could be a zero-blob.
+*/
+static int isAllZero(const char *z, int n){
+  int i;
+  for(i=0; i<n; i++){
+    if( z[i] ) return 0;
+  }
+  return 1;
+}
+
+/*
+** Compare two blobs.  Return negative, zero, or positive if the first
+** is less than, equal to, or greater than the second, respectively.
+** If one blob is a prefix of the other, then the shorter is the lessor.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3BlobCompare(const Mem *pB1, const Mem *pB2){
+  int c;
+  int n1 = pB1->n;
+  int n2 = pB2->n;
+
+  /* It is possible to have a Blob value that has some non-zero content
+  ** followed by zero content.  But that only comes up for Blobs formed
+  ** by the OP_MakeRecord opcode, and such Blobs never get passed into
+  ** sqlite3MemCompare(). */
+  assert( (pB1->flags & MEM_Zero)==0 || n1==0 );
+  assert( (pB2->flags & MEM_Zero)==0 || n2==0 );
+
+  if( (pB1->flags|pB2->flags) & MEM_Zero ){
+    if( pB1->flags & pB2->flags & MEM_Zero ){
+      return pB1->u.nZero - pB2->u.nZero;
+    }else if( pB1->flags & MEM_Zero ){
+      if( !isAllZero(pB2->z, pB2->n) ) return -1;
+      return pB1->u.nZero - n2;
+    }else{
+      if( !isAllZero(pB1->z, pB1->n) ) return +1;
+      return n1 - pB2->u.nZero;
+    }
+  }
+  c = memcmp(pB1->z, pB2->z, n1>n2 ? n2 : n1);
+  if( c ) return c;
+  return n1 - n2;
+}
+
+/* The following two functions are used only within testcase() to prove
+** test coverage.  These functions do no exist for production builds.
+** We must use separate SQLITE_NOINLINE functions here, since otherwise
+** optimizer code movement causes gcov to become very confused.
+*/
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_DEBUG)
+static int SQLITE_NOINLINE doubleLt(double a, double b){ return a<b; }
+static int SQLITE_NOINLINE doubleEq(double a, double b){ return a==b; }
+#endif
+
+/*
+** Do a comparison between a 64-bit signed integer and a 64-bit floating-point
+** number.  Return negative, zero, or positive if the first (i64) is less than,
+** equal to, or greater than the second (double).
+*/
+SQLITE_PRIVATE int sqlite3IntFloatCompare(i64 i, double r){
+  if( sqlite3IsNaN(r) ){
+    /* SQLite considers NaN to be a NULL. And all integer values are greater
+    ** than NULL */
+    return 1;
+  }else{
+    i64 y;
+    if( r<-9223372036854775808.0 ) return +1;
+    if( r>=9223372036854775808.0 ) return -1;
+    y = (i64)r;
+    if( i<y ) return -1;
+    if( i>y ) return +1;
+    testcase( doubleLt(((double)i),r) );
+    testcase( doubleLt(r,((double)i)) );
+    testcase( doubleEq(r,((double)i)) );
+    return (((double)i)<r) ? -1 : (((double)i)>r);
+  }
+}
+
+/*
+** Compare the values contained by the two memory cells, returning
+** negative, zero or positive if pMem1 is less than, equal to, or greater
+** than pMem2. Sorting order is NULL's first, followed by numbers (integers
+** and reals) sorted numerically, followed by text ordered by the collating
+** sequence pColl and finally blob's ordered by memcmp().
+**
+** Two NULL values are considered equal by this function.
+*/
+SQLITE_PRIVATE int sqlite3MemCompare(const Mem *pMem1, const Mem *pMem2, const CollSeq *pColl){
+  int f1, f2;
+  int combined_flags;
+
+  f1 = pMem1->flags;
+  f2 = pMem2->flags;
+  combined_flags = f1|f2;
+  assert( !sqlite3VdbeMemIsRowSet(pMem1) && !sqlite3VdbeMemIsRowSet(pMem2) );
+
+  /* If one value is NULL, it is less than the other. If both values
+  ** are NULL, return 0.
+  */
+  if( combined_flags&MEM_Null ){
+    return (f2&MEM_Null) - (f1&MEM_Null);
+  }
+
+  /* At least one of the two values is a number
+  */
+  if( combined_flags&(MEM_Int|MEM_Real|MEM_IntReal) ){
+    testcase( combined_flags & MEM_Int );
+    testcase( combined_flags & MEM_Real );
+    testcase( combined_flags & MEM_IntReal );
+    if( (f1 & f2 & (MEM_Int|MEM_IntReal))!=0 ){
+      testcase( f1 & f2 & MEM_Int );
+      testcase( f1 & f2 & MEM_IntReal );
+      if( pMem1->u.i < pMem2->u.i ) return -1;
+      if( pMem1->u.i > pMem2->u.i ) return +1;
+      return 0;
+    }
+    if( (f1 & f2 & MEM_Real)!=0 ){
+      if( pMem1->u.r < pMem2->u.r ) return -1;
+      if( pMem1->u.r > pMem2->u.r ) return +1;
+      return 0;
+    }
+    if( (f1&(MEM_Int|MEM_IntReal))!=0 ){
+      testcase( f1 & MEM_Int );
+      testcase( f1 & MEM_IntReal );
+      if( (f2&MEM_Real)!=0 ){
+        return sqlite3IntFloatCompare(pMem1->u.i, pMem2->u.r);
+      }else if( (f2&(MEM_Int|MEM_IntReal))!=0 ){
+        if( pMem1->u.i < pMem2->u.i ) return -1;
+        if( pMem1->u.i > pMem2->u.i ) return +1;
+        return 0;
+      }else{
+        return -1;
+      }
+    }
+    if( (f1&MEM_Real)!=0 ){
+      if( (f2&(MEM_Int|MEM_IntReal))!=0 ){
+        testcase( f2 & MEM_Int );
+        testcase( f2 & MEM_IntReal );
+        return -sqlite3IntFloatCompare(pMem2->u.i, pMem1->u.r);
+      }else{
+        return -1;
+      }
+    }
+    return +1;
+  }
+
+  /* If one value is a string and the other is a blob, the string is less.
+  ** If both are strings, compare using the collating functions.
+  */
+  if( combined_flags&MEM_Str ){
+    if( (f1 & MEM_Str)==0 ){
+      return 1;
+    }
+    if( (f2 & MEM_Str)==0 ){
+      return -1;
+    }
+
+    assert( pMem1->enc==pMem2->enc || pMem1->db->mallocFailed );
+    assert( pMem1->enc==SQLITE_UTF8 ||
+            pMem1->enc==SQLITE_UTF16LE || pMem1->enc==SQLITE_UTF16BE );
+
+    /* The collation sequence must be defined at this point, even if
+    ** the user deletes the collation sequence after the vdbe program is
+    ** compiled (this was not always the case).
+    */
+    assert( !pColl || pColl->xCmp );
+
+    if( pColl ){
+      return vdbeCompareMemString(pMem1, pMem2, pColl, 0);
+    }
+    /* If a NULL pointer was passed as the collate function, fall through
+    ** to the blob case and use memcmp().  */
+  }
+
+  /* Both values must be blobs.  Compare using memcmp().  */
+  return sqlite3BlobCompare(pMem1, pMem2);
+}
+
+
+/*
+** The first argument passed to this function is a serial-type that
+** corresponds to an integer - all values between 1 and 9 inclusive
+** except 7. The second points to a buffer containing an integer value
+** serialized according to serial_type. This function deserializes
+** and returns the value.
+*/
+static i64 vdbeRecordDecodeInt(u32 serial_type, const u8 *aKey){
+  u32 y;
+  assert( CORRUPT_DB || (serial_type>=1 && serial_type<=9 && serial_type!=7) );
+  switch( serial_type ){
+    case 0:
+    case 1:
+      testcase( aKey[0]&0x80 );
+      return ONE_BYTE_INT(aKey);
+    case 2:
+      testcase( aKey[0]&0x80 );
+      return TWO_BYTE_INT(aKey);
+    case 3:
+      testcase( aKey[0]&0x80 );
+      return THREE_BYTE_INT(aKey);
+    case 4: {
+      testcase( aKey[0]&0x80 );
+      y = FOUR_BYTE_UINT(aKey);
+      return (i64)*(int*)&y;
+    }
+    case 5: {
+      testcase( aKey[0]&0x80 );
+      return FOUR_BYTE_UINT(aKey+2) + (((i64)1)<<32)*TWO_BYTE_INT(aKey);
+    }
+    case 6: {
+      u64 x = FOUR_BYTE_UINT(aKey);
+      testcase( aKey[0]&0x80 );
+      x = (x<<32) | FOUR_BYTE_UINT(aKey+4);
+      return (i64)*(i64*)&x;
+    }
+  }
+
+  return (serial_type - 8);
+}
+
+/*
+** This function compares the two table rows or index records
+** specified by {nKey1, pKey1} and pPKey2.  It returns a negative, zero
+** or positive integer if key1 is less than, equal to or
+** greater than key2.  The {nKey1, pKey1} key must be a blob
+** created by the OP_MakeRecord opcode of the VDBE.  The pPKey2
+** key must be a parsed key such as obtained from
+** sqlite3VdbeParseRecord.
+**
+** If argument bSkip is non-zero, it is assumed that the caller has already
+** determined that the first fields of the keys are equal.
+**
+** Key1 and Key2 do not have to contain the same number of fields. If all
+** fields that appear in both keys are equal, then pPKey2->default_rc is
+** returned.
+**
+** If database corruption is discovered, set pPKey2->errCode to
+** SQLITE_CORRUPT and return 0. If an OOM error is encountered,
+** pPKey2->errCode is set to SQLITE_NOMEM and, if it is not NULL, the
+** malloc-failed flag set on database handle (pPKey2->pKeyInfo->db).
+*/
+SQLITE_PRIVATE int sqlite3VdbeRecordCompareWithSkip(
+  int nKey1, const void *pKey1,   /* Left key */
+  UnpackedRecord *pPKey2,         /* Right key */
+  int bSkip                       /* If true, skip the first field */
+){
+  u32 d1;                         /* Offset into aKey[] of next data element */
+  int i;                          /* Index of next field to compare */
+  u32 szHdr1;                     /* Size of record header in bytes */
+  u32 idx1;                       /* Offset of first type in header */
+  int rc = 0;                     /* Return value */
+  Mem *pRhs = pPKey2->aMem;       /* Next field of pPKey2 to compare */
+  KeyInfo *pKeyInfo;
+  const unsigned char *aKey1 = (const unsigned char *)pKey1;
+  Mem mem1;
+
+  /* If bSkip is true, then the caller has already determined that the first
+  ** two elements in the keys are equal. Fix the various stack variables so
+  ** that this routine begins comparing at the second field. */
+  if( bSkip ){
+    u32 s1 = aKey1[1];
+    if( s1<0x80 ){
+      idx1 = 2;
+    }else{
+      idx1 = 1 + sqlite3GetVarint32(&aKey1[1], &s1);
+    }
+    szHdr1 = aKey1[0];
+    d1 = szHdr1 + sqlite3VdbeSerialTypeLen(s1);
+    i = 1;
+    pRhs++;
+  }else{
+    if( (szHdr1 = aKey1[0])<0x80 ){
+      idx1 = 1;
+    }else{
+      idx1 = sqlite3GetVarint32(aKey1, &szHdr1);
+    }
+    d1 = szHdr1;
+    i = 0;
+  }
+  if( d1>(unsigned)nKey1 ){
+    pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+    return 0;  /* Corruption */
+  }
+
+  VVA_ONLY( mem1.szMalloc = 0; ) /* Only needed by assert() statements */
+  assert( pPKey2->pKeyInfo->nAllField>=pPKey2->nField
+       || CORRUPT_DB );
+  assert( pPKey2->pKeyInfo->aSortFlags!=0 );
+  assert( pPKey2->pKeyInfo->nKeyField>0 );
+  assert( idx1<=szHdr1 || CORRUPT_DB );
+  while( 1 /*exit-by-break*/ ){
+    u32 serial_type;
+
+    /* RHS is an integer */
+    if( pRhs->flags & (MEM_Int|MEM_IntReal) ){
+      testcase( pRhs->flags & MEM_Int );
+      testcase( pRhs->flags & MEM_IntReal );
+      serial_type = aKey1[idx1];
+      testcase( serial_type==12 );
+      if( serial_type>=10 ){
+        rc = serial_type==10 ? -1 : +1;
+      }else if( serial_type==0 ){
+        rc = -1;
+      }else if( serial_type==7 ){
+        serialGet7(&aKey1[d1], &mem1);
+        rc = -sqlite3IntFloatCompare(pRhs->u.i, mem1.u.r);
+      }else{
+        i64 lhs = vdbeRecordDecodeInt(serial_type, &aKey1[d1]);
+        i64 rhs = pRhs->u.i;
+        if( lhs<rhs ){
+          rc = -1;
+        }else if( lhs>rhs ){
+          rc = +1;
+        }
+      }
+    }
+
+    /* RHS is real */
+    else if( pRhs->flags & MEM_Real ){
+      serial_type = aKey1[idx1];
+      if( serial_type>=10 ){
+        /* Serial types 12 or greater are strings and blobs (greater than
+        ** numbers). Types 10 and 11 are currently "reserved for future
+        ** use", so it doesn't really matter what the results of comparing
+        ** them to numeric values are.  */
+        rc = serial_type==10 ? -1 : +1;
+      }else if( serial_type==0 ){
+        rc = -1;
+      }else{
+        if( serial_type==7 ){
+          if( serialGet7(&aKey1[d1], &mem1) ){
+            rc = -1;  /* mem1 is a NaN */
+          }else if( mem1.u.r<pRhs->u.r ){
+            rc = -1;
+          }else if( mem1.u.r>pRhs->u.r ){
+            rc = +1;
+          }else{
+            assert( rc==0 );
+          }
+        }else{
+          sqlite3VdbeSerialGet(&aKey1[d1], serial_type, &mem1);
+          rc = sqlite3IntFloatCompare(mem1.u.i, pRhs->u.r);
+        }
+      }
+    }
+
+    /* RHS is a string */
+    else if( pRhs->flags & MEM_Str ){
+      getVarint32NR(&aKey1[idx1], serial_type);
+      testcase( serial_type==12 );
+      if( serial_type<12 ){
+        rc = -1;
+      }else if( !(serial_type & 0x01) ){
+        rc = +1;
+      }else{
+        mem1.n = (serial_type - 12) / 2;
+        testcase( (d1+mem1.n)==(unsigned)nKey1 );
+        testcase( (d1+mem1.n+1)==(unsigned)nKey1 );
+        if( (d1+mem1.n) > (unsigned)nKey1
+         || (pKeyInfo = pPKey2->pKeyInfo)->nAllField<=i
+        ){
+          pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+          return 0;                /* Corruption */
+        }else if( pKeyInfo->aColl[i] ){
+          mem1.enc = pKeyInfo->enc;
+          mem1.db = pKeyInfo->db;
+          mem1.flags = MEM_Str;
+          mem1.z = (char*)&aKey1[d1];
+          rc = vdbeCompareMemString(
+              &mem1, pRhs, pKeyInfo->aColl[i], &pPKey2->errCode
+          );
+        }else{
+          int nCmp = MIN(mem1.n, pRhs->n);
+          rc = memcmp(&aKey1[d1], pRhs->z, nCmp);
+          if( rc==0 ) rc = mem1.n - pRhs->n;
+        }
+      }
+    }
+
+    /* RHS is a blob */
+    else if( pRhs->flags & MEM_Blob ){
+      assert( (pRhs->flags & MEM_Zero)==0 || pRhs->n==0 );
+      getVarint32NR(&aKey1[idx1], serial_type);
+      testcase( serial_type==12 );
+      if( serial_type<12 || (serial_type & 0x01) ){
+        rc = -1;
+      }else{
+        int nStr = (serial_type - 12) / 2;
+        testcase( (d1+nStr)==(unsigned)nKey1 );
+        testcase( (d1+nStr+1)==(unsigned)nKey1 );
+        if( (d1+nStr) > (unsigned)nKey1 ){
+          pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+          return 0;                /* Corruption */
+        }else if( pRhs->flags & MEM_Zero ){
+          if( !isAllZero((const char*)&aKey1[d1],nStr) ){
+            rc = 1;
+          }else{
+            rc = nStr - pRhs->u.nZero;
+          }
+        }else{
+          int nCmp = MIN(nStr, pRhs->n);
+          rc = memcmp(&aKey1[d1], pRhs->z, nCmp);
+          if( rc==0 ) rc = nStr - pRhs->n;
+        }
+      }
+    }
+
+    /* RHS is null */
+    else{
+      serial_type = aKey1[idx1];
+      if( serial_type==0
+       || serial_type==10
+       || (serial_type==7 && serialGet7(&aKey1[d1], &mem1)!=0)
+      ){
+        assert( rc==0 );
+      }else{
+        rc = 1;
+      }
+    }
+
+    if( rc!=0 ){
+      int sortFlags = pPKey2->pKeyInfo->aSortFlags[i];
+      if( sortFlags ){
+        if( (sortFlags & KEYINFO_ORDER_BIGNULL)==0
+         || ((sortFlags & KEYINFO_ORDER_DESC)
+           !=(serial_type==0 || (pRhs->flags&MEM_Null)))
+        ){
+          rc = -rc;
+        }
+      }
+      assert( vdbeRecordCompareDebug(nKey1, pKey1, pPKey2, rc) );
+      assert( mem1.szMalloc==0 );  /* See comment below */
+      return rc;
+    }
+
+    i++;
+    if( i==pPKey2->nField ) break;
+    pRhs++;
+    d1 += sqlite3VdbeSerialTypeLen(serial_type);
+    if( d1>(unsigned)nKey1 ) break;
+    idx1 += sqlite3VarintLen(serial_type);
+    if( idx1>=(unsigned)szHdr1 ){
+      pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+      return 0;  /* Corrupt index */
+    }
+  }
+
+  /* No memory allocation is ever used on mem1.  Prove this using
+  ** the following assert().  If the assert() fails, it indicates a
+  ** memory leak and a need to call sqlite3VdbeMemRelease(&mem1).  */
+  assert( mem1.szMalloc==0 );
+
+  /* rc==0 here means that one or both of the keys ran out of fields and
+  ** all the fields up to that point were equal. Return the default_rc
+  ** value.  */
+  assert( CORRUPT_DB
+       || vdbeRecordCompareDebug(nKey1, pKey1, pPKey2, pPKey2->default_rc)
+       || pPKey2->pKeyInfo->db->mallocFailed
+  );
+  pPKey2->eqSeen = 1;
+  return pPKey2->default_rc;
+}
+SQLITE_PRIVATE int sqlite3VdbeRecordCompare(
+  int nKey1, const void *pKey1,   /* Left key */
+  UnpackedRecord *pPKey2          /* Right key */
+){
+  return sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, pPKey2, 0);
+}
+
+
+/*
+** This function is an optimized version of sqlite3VdbeRecordCompare()
+** that (a) the first field of pPKey2 is an integer, and (b) the
+** size-of-header varint at the start of (pKey1/nKey1) fits in a single
+** byte (i.e. is less than 128).
+**
+** To avoid concerns about buffer overreads, this routine is only used
+** on schemas where the maximum valid header size is 63 bytes or less.
+*/
+static int vdbeRecordCompareInt(
+  int nKey1, const void *pKey1, /* Left key */
+  UnpackedRecord *pPKey2        /* Right key */
+){
+  const u8 *aKey = &((const u8*)pKey1)[*(const u8*)pKey1 & 0x3F];
+  int serial_type = ((const u8*)pKey1)[1];
+  int res;
+  u32 y;
+  u64 x;
+  i64 v;
+  i64 lhs;
+
+  vdbeAssertFieldCountWithinLimits(nKey1, pKey1, pPKey2->pKeyInfo);
+  assert( (*(u8*)pKey1)<=0x3F || CORRUPT_DB );
+  switch( serial_type ){
+    case 1: { /* 1-byte signed integer */
+      lhs = ONE_BYTE_INT(aKey);
+      testcase( lhs<0 );
+      break;
+    }
+    case 2: { /* 2-byte signed integer */
+      lhs = TWO_BYTE_INT(aKey);
+      testcase( lhs<0 );
+      break;
+    }
+    case 3: { /* 3-byte signed integer */
+      lhs = THREE_BYTE_INT(aKey);
+      testcase( lhs<0 );
+      break;
+    }
+    case 4: { /* 4-byte signed integer */
+      y = FOUR_BYTE_UINT(aKey);
+      lhs = (i64)*(int*)&y;
+      testcase( lhs<0 );
+      break;
+    }
+    case 5: { /* 6-byte signed integer */
+      lhs = FOUR_BYTE_UINT(aKey+2) + (((i64)1)<<32)*TWO_BYTE_INT(aKey);
+      testcase( lhs<0 );
+      break;
+    }
+    case 6: { /* 8-byte signed integer */
+      x = FOUR_BYTE_UINT(aKey);
+      x = (x<<32) | FOUR_BYTE_UINT(aKey+4);
+      lhs = *(i64*)&x;
+      testcase( lhs<0 );
+      break;
+    }
+    case 8:
+      lhs = 0;
+      break;
+    case 9:
+      lhs = 1;
+      break;
+
+    /* This case could be removed without changing the results of running
+    ** this code. Including it causes gcc to generate a faster switch
+    ** statement (since the range of switch targets now starts at zero and
+    ** is contiguous) but does not cause any duplicate code to be generated
+    ** (as gcc is clever enough to combine the two like cases). Other
+    ** compilers might be similar.  */
+    case 0: case 7:
+      return sqlite3VdbeRecordCompare(nKey1, pKey1, pPKey2);
+
+    default:
+      return sqlite3VdbeRecordCompare(nKey1, pKey1, pPKey2);
+  }
+
+  assert( pPKey2->u.i == pPKey2->aMem[0].u.i );
+  v = pPKey2->u.i;
+  if( v>lhs ){
+    res = pPKey2->r1;
+  }else if( v<lhs ){
+    res = pPKey2->r2;
+  }else if( pPKey2->nField>1 ){
+    /* The first fields of the two keys are equal. Compare the trailing
+    ** fields.  */
+    res = sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, pPKey2, 1);
+  }else{
+    /* The first fields of the two keys are equal and there are no trailing
+    ** fields. Return pPKey2->default_rc in this case. */
+    res = pPKey2->default_rc;
+    pPKey2->eqSeen = 1;
+  }
+
+  assert( vdbeRecordCompareDebug(nKey1, pKey1, pPKey2, res) );
+  return res;
+}
+
+/*
+** This function is an optimized version of sqlite3VdbeRecordCompare()
+** that (a) the first field of pPKey2 is a string, that (b) the first field
+** uses the collation sequence BINARY and (c) that the size-of-header varint
+** at the start of (pKey1/nKey1) fits in a single byte.
+*/
+static int vdbeRecordCompareString(
+  int nKey1, const void *pKey1, /* Left key */
+  UnpackedRecord *pPKey2        /* Right key */
+){
+  const u8 *aKey1 = (const u8*)pKey1;
+  int serial_type;
+  int res;
+
+  assert( pPKey2->aMem[0].flags & MEM_Str );
+  assert( pPKey2->aMem[0].n == pPKey2->n );
+  assert( pPKey2->aMem[0].z == pPKey2->u.z );
+  vdbeAssertFieldCountWithinLimits(nKey1, pKey1, pPKey2->pKeyInfo);
+  serial_type = (signed char)(aKey1[1]);
+
+vrcs_restart:
+  if( serial_type<12 ){
+    if( serial_type<0 ){
+      sqlite3GetVarint32(&aKey1[1], (u32*)&serial_type);
+      if( serial_type>=12 ) goto vrcs_restart;
+      assert( CORRUPT_DB );
+    }
+    res = pPKey2->r1;      /* (pKey1/nKey1) is a number or a null */
+  }else if( !(serial_type & 0x01) ){
+    res = pPKey2->r2;      /* (pKey1/nKey1) is a blob */
+  }else{
+    int nCmp;
+    int nStr;
+    int szHdr = aKey1[0];
+
+    nStr = (serial_type-12) / 2;
+    if( (szHdr + nStr) > nKey1 ){
+      pPKey2->errCode = (u8)SQLITE_CORRUPT_BKPT;
+      return 0;    /* Corruption */
+    }
+    nCmp = MIN( pPKey2->n, nStr );
+    res = memcmp(&aKey1[szHdr], pPKey2->u.z, nCmp);
+
+    if( res>0 ){
+      res = pPKey2->r2;
+    }else if( res<0 ){
+      res = pPKey2->r1;
+    }else{
+      res = nStr - pPKey2->n;
+      if( res==0 ){
+        if( pPKey2->nField>1 ){
+          res = sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, pPKey2, 1);
+        }else{
+          res = pPKey2->default_rc;
+          pPKey2->eqSeen = 1;
+        }
+      }else if( res>0 ){
+        res = pPKey2->r2;
+      }else{
+        res = pPKey2->r1;
+      }
+    }
+  }
+
+  assert( vdbeRecordCompareDebug(nKey1, pKey1, pPKey2, res)
+       || CORRUPT_DB
+       || pPKey2->pKeyInfo->db->mallocFailed
+  );
+  return res;
+}
+
+/*
+** Return a pointer to an sqlite3VdbeRecordCompare() compatible function
+** suitable for comparing serialized records to the unpacked record passed
+** as the only argument.
+*/
+SQLITE_PRIVATE RecordCompare sqlite3VdbeFindCompare(UnpackedRecord *p){
+  /* varintRecordCompareInt() and varintRecordCompareString() both assume
+  ** that the size-of-header varint that occurs at the start of each record
+  ** fits in a single byte (i.e. is 127 or less). varintRecordCompareInt()
+  ** also assumes that it is safe to overread a buffer by at least the
+  ** maximum possible legal header size plus 8 bytes. Because there is
+  ** guaranteed to be at least 74 (but not 136) bytes of padding following each
+  ** buffer passed to varintRecordCompareInt() this makes it convenient to
+  ** limit the size of the header to 64 bytes in cases where the first field
+  ** is an integer.
+  **
+  ** The easiest way to enforce this limit is to consider only records with
+  ** 13 fields or less. If the first field is an integer, the maximum legal
+  ** header size is (12*5 + 1 + 1) bytes.  */
+  if( p->pKeyInfo->nAllField<=13 ){
+    int flags = p->aMem[0].flags;
+    if( p->pKeyInfo->aSortFlags[0] ){
+      if( p->pKeyInfo->aSortFlags[0] & KEYINFO_ORDER_BIGNULL ){
+        return sqlite3VdbeRecordCompare;
+      }
+      p->r1 = 1;
+      p->r2 = -1;
+    }else{
+      p->r1 = -1;
+      p->r2 = 1;
+    }
+    if( (flags & MEM_Int) ){
+      p->u.i = p->aMem[0].u.i;
+      return vdbeRecordCompareInt;
+    }
+    testcase( flags & MEM_Real );
+    testcase( flags & MEM_Null );
+    testcase( flags & MEM_Blob );
+    if( (flags & (MEM_Real|MEM_IntReal|MEM_Null|MEM_Blob))==0
+     && p->pKeyInfo->aColl[0]==0
+    ){
+      assert( flags & MEM_Str );
+      p->u.z = p->aMem[0].z;
+      p->n = p->aMem[0].n;
+      return vdbeRecordCompareString;
+    }
+  }
+
+  return sqlite3VdbeRecordCompare;
+}
+
+/*
+** pCur points at an index entry created using the OP_MakeRecord opcode.
+** Read the rowid (the last field in the record) and store it in *rowid.
+** Return SQLITE_OK if everything works, or an error code otherwise.
+**
+** pCur might be pointing to text obtained from a corrupt database file.
+** So the content cannot be trusted.  Do appropriate checks on the content.
+*/
+SQLITE_PRIVATE int sqlite3VdbeIdxRowid(sqlite3 *db, BtCursor *pCur, i64 *rowid){
+  i64 nCellKey = 0;
+  int rc;
+  u32 szHdr;        /* Size of the header */
+  u32 typeRowid;    /* Serial type of the rowid */
+  u32 lenRowid;     /* Size of the rowid */
+  Mem m, v;
+
+  /* Get the size of the index entry.  Only indices entries of less
+  ** than 2GiB are support - anything large must be database corruption.
+  ** Any corruption is detected in sqlite3BtreeParseCellPtr(), though, so
+  ** this code can safely assume that nCellKey is 32-bits
+  */
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+  nCellKey = sqlite3BtreePayloadSize(pCur);
+  assert( (nCellKey & SQLITE_MAX_U32)==(u64)nCellKey );
+
+  /* Read in the complete content of the index entry */
+  sqlite3VdbeMemInit(&m, db, 0);
+  rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
+  if( rc ){
+    return rc;
+  }
+
+  /* The index entry must begin with a header size */
+  getVarint32NR((u8*)m.z, szHdr);
+  testcase( szHdr==3 );
+  testcase( szHdr==(u32)m.n );
+  testcase( szHdr>0x7fffffff );
+  assert( m.n>=0 );
+  if( unlikely(szHdr<3 || szHdr>(unsigned)m.n) ){
+    goto idx_rowid_corruption;
+  }
+
+  /* The last field of the index should be an integer - the ROWID.
+  ** Verify that the last entry really is an integer. */
+  getVarint32NR((u8*)&m.z[szHdr-1], typeRowid);
+  testcase( typeRowid==1 );
+  testcase( typeRowid==2 );
+  testcase( typeRowid==3 );
+  testcase( typeRowid==4 );
+  testcase( typeRowid==5 );
+  testcase( typeRowid==6 );
+  testcase( typeRowid==8 );
+  testcase( typeRowid==9 );
+  if( unlikely(typeRowid<1 || typeRowid>9 || typeRowid==7) ){
+    goto idx_rowid_corruption;
+  }
+  lenRowid = sqlite3SmallTypeSizes[typeRowid];
+  testcase( (u32)m.n==szHdr+lenRowid );
+  if( unlikely((u32)m.n<szHdr+lenRowid) ){
+    goto idx_rowid_corruption;
+  }
+
+  /* Fetch the integer off the end of the index record */
+  sqlite3VdbeSerialGet((u8*)&m.z[m.n-lenRowid], typeRowid, &v);
+  *rowid = v.u.i;
+  sqlite3VdbeMemReleaseMalloc(&m);
+  return SQLITE_OK;
+
+  /* Jump here if database corruption is detected after m has been
+  ** allocated.  Free the m object and return SQLITE_CORRUPT. */
+idx_rowid_corruption:
+  testcase( m.szMalloc!=0 );
+  sqlite3VdbeMemReleaseMalloc(&m);
+  return SQLITE_CORRUPT_BKPT;
+}
+
+/*
+** Compare the key of the index entry that cursor pC is pointing to against
+** the key string in pUnpacked.  Write into *pRes a number
+** that is negative, zero, or positive if pC is less than, equal to,
+** or greater than pUnpacked.  Return SQLITE_OK on success.
+**
+** pUnpacked is either created without a rowid or is truncated so that it
+** omits the rowid at the end.  The rowid at the end of the index entry
+** is ignored as well.  Hence, this routine only compares the prefixes
+** of the keys prior to the final rowid, not the entire key.
+*/
+SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(
+  sqlite3 *db,                     /* Database connection */
+  VdbeCursor *pC,                  /* The cursor to compare against */
+  UnpackedRecord *pUnpacked,       /* Unpacked version of key */
+  int *res                         /* Write the comparison result here */
+){
+  i64 nCellKey = 0;
+  int rc;
+  BtCursor *pCur;
+  Mem m;
+
+  assert( pC->eCurType==CURTYPE_BTREE );
+  pCur = pC->uc.pCursor;
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+  nCellKey = sqlite3BtreePayloadSize(pCur);
+  /* nCellKey will always be between 0 and 0xffffffff because of the way
+  ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
+  if( nCellKey<=0 || nCellKey>0x7fffffff ){
+    *res = 0;
+    return SQLITE_CORRUPT_BKPT;
+  }
+  sqlite3VdbeMemInit(&m, db, 0);
+  rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
+  if( rc ){
+    return rc;
+  }
+  *res = sqlite3VdbeRecordCompareWithSkip(m.n, m.z, pUnpacked, 0);
+  sqlite3VdbeMemReleaseMalloc(&m);
+  return SQLITE_OK;
+}
+
+/*
+** This routine sets the value to be returned by subsequent calls to
+** sqlite3_changes() on the database handle 'db'.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetChanges(sqlite3 *db, i64 nChange){
+  assert( sqlite3_mutex_held(db->mutex) );
+  db->nChange = nChange;
+  db->nTotalChange += nChange;
+}
+
+/*
+** Set a flag in the vdbe to update the change counter when it is finalised
+** or reset.
+*/
+SQLITE_PRIVATE void sqlite3VdbeCountChanges(Vdbe *v){
+  v->changeCntOn = 1;
+}
+
+/*
+** Mark every prepared statement associated with a database connection
+** as expired.
+**
+** An expired statement means that recompilation of the statement is
+** recommend.  Statements expire when things happen that make their
+** programs obsolete.  Removing user-defined functions or collating
+** sequences, or changing an authorization function are the types of
+** things that make prepared statements obsolete.
+**
+** If iCode is 1, then expiration is advisory.  The statement should
+** be reprepared before being restarted, but if it is already running
+** it is allowed to run to completion.
+**
+** Internally, this function just sets the Vdbe.expired flag on all
+** prepared statements.  The flag is set to 1 for an immediate expiration
+** and set to 2 for an advisory expiration.
+*/
+SQLITE_PRIVATE void sqlite3ExpirePreparedStatements(sqlite3 *db, int iCode){
+  Vdbe *p;
+  for(p = db->pVdbe; p; p=p->pVNext){
+    p->expired = iCode+1;
+  }
+}
+
+/*
+** Return the database associated with the Vdbe.
+*/
+SQLITE_PRIVATE sqlite3 *sqlite3VdbeDb(Vdbe *v){
+  return v->db;
+}
+
+/*
+** Return the SQLITE_PREPARE flags for a Vdbe.
+*/
+SQLITE_PRIVATE u8 sqlite3VdbePrepareFlags(Vdbe *v){
+  return v->prepFlags;
+}
+
+/*
+** Return a pointer to an sqlite3_value structure containing the value bound
+** parameter iVar of VM v. Except, if the value is an SQL NULL, return
+** 0 instead. Unless it is NULL, apply affinity aff (one of the SQLITE_AFF_*
+** constants) to the value before returning it.
+**
+** The returned value must be freed by the caller using sqlite3ValueFree().
+*/
+SQLITE_PRIVATE sqlite3_value *sqlite3VdbeGetBoundValue(Vdbe *v, int iVar, u8 aff){
+  assert( iVar>0 );
+  if( v ){
+    Mem *pMem = &v->aVar[iVar-1];
+    assert( (v->db->flags & SQLITE_EnableQPSG)==0
+         || (v->db->mDbFlags & DBFLAG_InternalFunc)!=0 );
+    if( 0==(pMem->flags & MEM_Null) ){
+      sqlite3_value *pRet = sqlite3ValueNew(v->db);
+      if( pRet ){
+        sqlite3VdbeMemCopy((Mem *)pRet, pMem);
+        sqlite3ValueApplyAffinity(pRet, aff, SQLITE_UTF8);
+      }
+      return pRet;
+    }
+  }
+  return 0;
+}
+
+/*
+** Configure SQL variable iVar so that binding a new value to it signals
+** to sqlite3_reoptimize() that re-preparing the statement may result
+** in a better query plan.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSetVarmask(Vdbe *v, int iVar){
+  assert( iVar>0 );
+  assert( (v->db->flags & SQLITE_EnableQPSG)==0
+       || (v->db->mDbFlags & DBFLAG_InternalFunc)!=0 );
+  if( iVar>=32 ){
+    v->expmask |= 0x80000000;
+  }else{
+    v->expmask |= ((u32)1 << (iVar-1));
+  }
+}
+
+/*
+** Cause a function to throw an error if it was call from OP_PureFunc
+** rather than OP_Function.
+**
+** OP_PureFunc means that the function must be deterministic, and should
+** throw an error if it is given inputs that would make it non-deterministic.
+** This routine is invoked by date/time functions that use non-deterministic
+** features such as 'now'.
+*/
+SQLITE_PRIVATE int sqlite3NotPureFunc(sqlite3_context *pCtx){
+  const VdbeOp *pOp;
+#ifdef SQLITE_ENABLE_STAT4
+  if( pCtx->pVdbe==0 ) return 1;
+#endif
+  pOp = pCtx->pVdbe->aOp + pCtx->iOp;
+  if( pOp->opcode==OP_PureFunc ){
+    const char *zContext;
+    char *zMsg;
+    if( pOp->p5 & NC_IsCheck ){
+      zContext = "a CHECK constraint";
+    }else if( pOp->p5 & NC_GenCol ){
+      zContext = "a generated column";
+    }else{
+      zContext = "an index";
+    }
+    zMsg = sqlite3_mprintf("non-deterministic use of %s() in %s",
+                           pCtx->pFunc->zName, zContext);
+    sqlite3_result_error(pCtx, zMsg, -1);
+    sqlite3_free(zMsg);
+    return 0;
+  }
+  return 1;
+}
+
+#if defined(SQLITE_ENABLE_CURSOR_HINTS) && defined(SQLITE_DEBUG)
+/*
+** This Walker callback is used to help verify that calls to
+** sqlite3BtreeCursorHint() with opcode BTREE_HINT_RANGE have
+** byte-code register values correctly initialized.
+*/
+SQLITE_PRIVATE int sqlite3CursorRangeHintExprCheck(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_REGISTER ){
+    assert( (pWalker->u.aMem[pExpr->iTable].flags & MEM_Undefined)==0 );
+  }
+  return WRC_Continue;
+}
+#endif /* SQLITE_ENABLE_CURSOR_HINTS && SQLITE_DEBUG */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Transfer error message text from an sqlite3_vtab.zErrMsg (text stored
+** in memory obtained from sqlite3_malloc) into a Vdbe.zErrMsg (text stored
+** in memory obtained from sqlite3DbMalloc).
+*/
+SQLITE_PRIVATE void sqlite3VtabImportErrmsg(Vdbe *p, sqlite3_vtab *pVtab){
+  if( pVtab->zErrMsg ){
+    sqlite3 *db = p->db;
+    sqlite3DbFree(db, p->zErrMsg);
+    p->zErrMsg = sqlite3DbStrDup(db, pVtab->zErrMsg);
+    sqlite3_free(pVtab->zErrMsg);
+    pVtab->zErrMsg = 0;
+  }
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+
+/*
+** If the second argument is not NULL, release any allocations associated
+** with the memory cells in the p->aMem[] array. Also free the UnpackedRecord
+** structure itself, using sqlite3DbFree().
+**
+** This function is used to free UnpackedRecord structures allocated by
+** the vdbeUnpackRecord() function found in vdbeapi.c.
+*/
+static void vdbeFreeUnpacked(sqlite3 *db, int nField, UnpackedRecord *p){
+  assert( db!=0 );
+  if( p ){
+    int i;
+    for(i=0; i<nField; i++){
+      Mem *pMem = &p->aMem[i];
+      if( pMem->zMalloc ) sqlite3VdbeMemReleaseMalloc(pMem);
+    }
+    sqlite3DbNNFreeNN(db, p);
+  }
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** Invoke the pre-update hook. If this is an UPDATE or DELETE pre-update call,
+** then cursor passed as the second argument should point to the row about
+** to be update or deleted. If the application calls sqlite3_preupdate_old(),
+** the required value will be read from the row the cursor points to.
+*/
+SQLITE_PRIVATE void sqlite3VdbePreUpdateHook(
+  Vdbe *v,                        /* Vdbe pre-update hook is invoked by */
+  VdbeCursor *pCsr,               /* Cursor to grab old.* values from */
+  int op,                         /* SQLITE_INSERT, UPDATE or DELETE */
+  const char *zDb,                /* Database name */
+  Table *pTab,                    /* Modified table */
+  i64 iKey1,                      /* Initial key value */
+  int iReg,                       /* Register for new.* record */
+  int iBlobWrite
+){
+  sqlite3 *db = v->db;
+  i64 iKey2;
+  PreUpdate preupdate;
+  const char *zTbl = pTab->zName;
+  static const u8 fakeSortOrder = 0;
+#ifdef SQLITE_DEBUG
+  int nRealCol;
+  if( pTab->tabFlags & TF_WithoutRowid ){
+    nRealCol = sqlite3PrimaryKeyIndex(pTab)->nColumn;
+  }else if( pTab->tabFlags & TF_HasVirtual ){
+    nRealCol = pTab->nNVCol;
+  }else{
+    nRealCol = pTab->nCol;
+  }
+#endif
+
+  assert( db->pPreUpdate==0 );
+  memset(&preupdate, 0, sizeof(PreUpdate));
+  if( HasRowid(pTab)==0 ){
+    iKey1 = iKey2 = 0;
+    preupdate.pPk = sqlite3PrimaryKeyIndex(pTab);
+  }else{
+    if( op==SQLITE_UPDATE ){
+      iKey2 = v->aMem[iReg].u.i;
+    }else{
+      iKey2 = iKey1;
+    }
+  }
+
+  assert( pCsr!=0 );
+  assert( pCsr->eCurType==CURTYPE_BTREE );
+  assert( pCsr->nField==nRealCol
+       || (pCsr->nField==nRealCol+1 && op==SQLITE_DELETE && iReg==-1)
+  );
+
+  preupdate.v = v;
+  preupdate.pCsr = pCsr;
+  preupdate.op = op;
+  preupdate.iNewReg = iReg;
+  preupdate.keyinfo.db = db;
+  preupdate.keyinfo.enc = ENC(db);
+  preupdate.keyinfo.nKeyField = pTab->nCol;
+  preupdate.keyinfo.aSortFlags = (u8*)&fakeSortOrder;
+  preupdate.iKey1 = iKey1;
+  preupdate.iKey2 = iKey2;
+  preupdate.pTab = pTab;
+  preupdate.iBlobWrite = iBlobWrite;
+
+  db->pPreUpdate = &preupdate;
+  db->xPreUpdateCallback(db->pPreUpdateArg, db, op, zDb, zTbl, iKey1, iKey2);
+  db->pPreUpdate = 0;
+  sqlite3DbFree(db, preupdate.aRecord);
+  vdbeFreeUnpacked(db, preupdate.keyinfo.nKeyField+1, preupdate.pUnpacked);
+  vdbeFreeUnpacked(db, preupdate.keyinfo.nKeyField+1, preupdate.pNewUnpacked);
+  sqlite3VdbeMemRelease(&preupdate.oldipk);
+  if( preupdate.aNew ){
+    int i;
+    for(i=0; i<pCsr->nField; i++){
+      sqlite3VdbeMemRelease(&preupdate.aNew[i]);
+    }
+    sqlite3DbNNFreeNN(db, preupdate.aNew);
+  }
+  if( preupdate.apDflt ){
+    int i;
+    for(i=0; i<pTab->nCol; i++){
+      sqlite3ValueFree(preupdate.apDflt[i]);
+    }
+    sqlite3DbFree(db, preupdate.apDflt);
+  }
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+/************** End of vdbeaux.c *********************************************/
+/************** Begin file vdbeapi.c *****************************************/
+/*
+** 2004 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code use to implement APIs that are part of the
+** VDBE.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+/* #include "opcodes.h" */
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Return TRUE (non-zero) of the statement supplied as an argument needs
+** to be recompiled.  A statement needs to be recompiled whenever the
+** execution environment changes in a way that would alter the program
+** that sqlite3_prepare() generates.  For example, if new functions or
+** collating sequences are registered or if an authorizer function is
+** added or changed.
+*/
+SQLITE_API int sqlite3_expired(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe*)pStmt;
+  return p==0 || p->expired;
+}
+#endif
+
+/*
+** Check on a Vdbe to make sure it has not been finalized.  Log
+** an error and return true if it has been finalized (or is otherwise
+** invalid).  Return false if it is ok.
+*/
+static int vdbeSafety(Vdbe *p){
+  if( p->db==0 ){
+    sqlite3_log(SQLITE_MISUSE, "API called with finalized prepared statement");
+    return 1;
+  }else{
+    return 0;
+  }
+}
+static int vdbeSafetyNotNull(Vdbe *p){
+  if( p==0 ){
+    sqlite3_log(SQLITE_MISUSE, "API called with NULL prepared statement");
+    return 1;
+  }else{
+    return vdbeSafety(p);
+  }
+}
+
+#ifndef SQLITE_OMIT_TRACE
+/*
+** Invoke the profile callback.  This routine is only called if we already
+** know that the profile callback is defined and needs to be invoked.
+*/
+static SQLITE_NOINLINE void invokeProfileCallback(sqlite3 *db, Vdbe *p){
+  sqlite3_int64 iNow;
+  sqlite3_int64 iElapse;
+  assert( p->startTime>0 );
+  assert( db->init.busy==0 );
+  assert( p->zSql!=0 );
+  sqlite3OsCurrentTimeInt64(db->pVfs, &iNow);
+  iElapse = (iNow - p->startTime)*1000000;
+#ifndef SQLITE_OMIT_DEPRECATED
+  if( db->xProfile ){
+    db->xProfile(db->pProfileArg, p->zSql, iElapse);
+  }
+#endif
+  if( db->mTrace & SQLITE_TRACE_PROFILE ){
+    db->trace.xV2(SQLITE_TRACE_PROFILE, db->pTraceArg, p, (void*)&iElapse);
+  }
+  p->startTime = 0;
+}
+/*
+** The checkProfileCallback(DB,P) macro checks to see if a profile callback
+** is needed, and it invokes the callback if it is needed.
+*/
+# define checkProfileCallback(DB,P) \
+   if( ((P)->startTime)>0 ){ invokeProfileCallback(DB,P); }
+#else
+# define checkProfileCallback(DB,P)  /*no-op*/
+#endif
+
+/*
+** The following routine destroys a virtual machine that is created by
+** the sqlite3_compile() routine. The integer returned is an SQLITE_
+** success/failure code that describes the result of executing the virtual
+** machine.
+**
+** This routine sets the error code and string returned by
+** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
+*/
+SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt){
+  int rc;
+  if( pStmt==0 ){
+    /* IMPLEMENTATION-OF: R-57228-12904 Invoking sqlite3_finalize() on a NULL
+    ** pointer is a harmless no-op. */
+    rc = SQLITE_OK;
+  }else{
+    Vdbe *v = (Vdbe*)pStmt;
+    sqlite3 *db = v->db;
+    if( vdbeSafety(v) ) return SQLITE_MISUSE_BKPT;
+    sqlite3_mutex_enter(db->mutex);
+    checkProfileCallback(db, v);
+    assert( v->eVdbeState>=VDBE_READY_STATE );
+    rc = sqlite3VdbeReset(v);
+    sqlite3VdbeDelete(v);
+    rc = sqlite3ApiExit(db, rc);
+    sqlite3LeaveMutexAndCloseZombie(db);
+  }
+  return rc;
+}
+
+/*
+** Terminate the current execution of an SQL statement and reset it
+** back to its starting state so that it can be reused. A success code from
+** the prior execution is returned.
+**
+** This routine sets the error code and string returned by
+** sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16().
+*/
+SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt){
+  int rc;
+  if( pStmt==0 ){
+    rc = SQLITE_OK;
+  }else{
+    Vdbe *v = (Vdbe*)pStmt;
+    sqlite3 *db = v->db;
+    sqlite3_mutex_enter(db->mutex);
+    checkProfileCallback(db, v);
+    rc = sqlite3VdbeReset(v);
+    sqlite3VdbeRewind(v);
+    assert( (rc & (db->errMask))==rc );
+    rc = sqlite3ApiExit(db, rc);
+    sqlite3_mutex_leave(db->mutex);
+  }
+  return rc;
+}
+
+/*
+** Set all the parameters in the compiled SQL statement to NULL.
+*/
+SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt *pStmt){
+  int i;
+  int rc = SQLITE_OK;
+  Vdbe *p = (Vdbe*)pStmt;
+#if SQLITE_THREADSAFE
+  sqlite3_mutex *mutex;
+#endif
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pStmt==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+#if SQLITE_THREADSAFE
+  mutex = p->db->mutex;
+#endif
+  sqlite3_mutex_enter(mutex);
+  for(i=0; i<p->nVar; i++){
+    sqlite3VdbeMemRelease(&p->aVar[i]);
+    p->aVar[i].flags = MEM_Null;
+  }
+  assert( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || p->expmask==0 );
+  if( p->expmask ){
+    p->expired = 1;
+  }
+  sqlite3_mutex_leave(mutex);
+  return rc;
+}
+
+
+/**************************** sqlite3_value_  *******************************
+** The following routines extract information from a Mem or sqlite3_value
+** structure.
+*/
+SQLITE_API const void *sqlite3_value_blob(sqlite3_value *pVal){
+  Mem *p = (Mem*)pVal;
+  if( p->flags & (MEM_Blob|MEM_Str) ){
+    if( ExpandBlob(p)!=SQLITE_OK ){
+      assert( p->flags==MEM_Null && p->z==0 );
+      return 0;
+    }
+    p->flags |= MEM_Blob;
+    return p->n ? p->z : 0;
+  }else{
+    return sqlite3_value_text(pVal);
+  }
+}
+SQLITE_API int sqlite3_value_bytes(sqlite3_value *pVal){
+  return sqlite3ValueBytes(pVal, SQLITE_UTF8);
+}
+SQLITE_API int sqlite3_value_bytes16(sqlite3_value *pVal){
+  return sqlite3ValueBytes(pVal, SQLITE_UTF16NATIVE);
+}
+SQLITE_API double sqlite3_value_double(sqlite3_value *pVal){
+  return sqlite3VdbeRealValue((Mem*)pVal);
+}
+SQLITE_API int sqlite3_value_int(sqlite3_value *pVal){
+  return (int)sqlite3VdbeIntValue((Mem*)pVal);
+}
+SQLITE_API sqlite_int64 sqlite3_value_int64(sqlite3_value *pVal){
+  return sqlite3VdbeIntValue((Mem*)pVal);
+}
+SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value *pVal){
+  Mem *pMem = (Mem*)pVal;
+  return ((pMem->flags & MEM_Subtype) ? pMem->eSubtype : 0);
+}
+SQLITE_API void *sqlite3_value_pointer(sqlite3_value *pVal, const char *zPType){
+  Mem *p = (Mem*)pVal;
+  if( (p->flags&(MEM_TypeMask|MEM_Term|MEM_Subtype)) ==
+                 (MEM_Null|MEM_Term|MEM_Subtype)
+   && zPType!=0
+   && p->eSubtype=='p'
+   && strcmp(p->u.zPType, zPType)==0
+  ){
+    return (void*)p->z;
+  }else{
+    return 0;
+  }
+}
+SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value *pVal){
+  return (const unsigned char *)sqlite3ValueText(pVal, SQLITE_UTF8);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_value_text16(sqlite3_value* pVal){
+  return sqlite3ValueText(pVal, SQLITE_UTF16NATIVE);
+}
+SQLITE_API const void *sqlite3_value_text16be(sqlite3_value *pVal){
+  return sqlite3ValueText(pVal, SQLITE_UTF16BE);
+}
+SQLITE_API const void *sqlite3_value_text16le(sqlite3_value *pVal){
+  return sqlite3ValueText(pVal, SQLITE_UTF16LE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+/* EVIDENCE-OF: R-12793-43283 Every value in SQLite has one of five
+** fundamental datatypes: 64-bit signed integer 64-bit IEEE floating
+** point number string BLOB NULL
+*/
+SQLITE_API int sqlite3_value_type(sqlite3_value* pVal){
+  static const u8 aType[] = {
+     SQLITE_BLOB,     /* 0x00 (not possible) */
+     SQLITE_NULL,     /* 0x01 NULL */
+     SQLITE_TEXT,     /* 0x02 TEXT */
+     SQLITE_NULL,     /* 0x03 (not possible) */
+     SQLITE_INTEGER,  /* 0x04 INTEGER */
+     SQLITE_NULL,     /* 0x05 (not possible) */
+     SQLITE_INTEGER,  /* 0x06 INTEGER + TEXT */
+     SQLITE_NULL,     /* 0x07 (not possible) */
+     SQLITE_FLOAT,    /* 0x08 FLOAT */
+     SQLITE_NULL,     /* 0x09 (not possible) */
+     SQLITE_FLOAT,    /* 0x0a FLOAT + TEXT */
+     SQLITE_NULL,     /* 0x0b (not possible) */
+     SQLITE_INTEGER,  /* 0x0c (not possible) */
+     SQLITE_NULL,     /* 0x0d (not possible) */
+     SQLITE_INTEGER,  /* 0x0e (not possible) */
+     SQLITE_NULL,     /* 0x0f (not possible) */
+     SQLITE_BLOB,     /* 0x10 BLOB */
+     SQLITE_NULL,     /* 0x11 (not possible) */
+     SQLITE_TEXT,     /* 0x12 (not possible) */
+     SQLITE_NULL,     /* 0x13 (not possible) */
+     SQLITE_INTEGER,  /* 0x14 INTEGER + BLOB */
+     SQLITE_NULL,     /* 0x15 (not possible) */
+     SQLITE_INTEGER,  /* 0x16 (not possible) */
+     SQLITE_NULL,     /* 0x17 (not possible) */
+     SQLITE_FLOAT,    /* 0x18 FLOAT + BLOB */
+     SQLITE_NULL,     /* 0x19 (not possible) */
+     SQLITE_FLOAT,    /* 0x1a (not possible) */
+     SQLITE_NULL,     /* 0x1b (not possible) */
+     SQLITE_INTEGER,  /* 0x1c (not possible) */
+     SQLITE_NULL,     /* 0x1d (not possible) */
+     SQLITE_INTEGER,  /* 0x1e (not possible) */
+     SQLITE_NULL,     /* 0x1f (not possible) */
+     SQLITE_FLOAT,    /* 0x20 INTREAL */
+     SQLITE_NULL,     /* 0x21 (not possible) */
+     SQLITE_FLOAT,    /* 0x22 INTREAL + TEXT */
+     SQLITE_NULL,     /* 0x23 (not possible) */
+     SQLITE_FLOAT,    /* 0x24 (not possible) */
+     SQLITE_NULL,     /* 0x25 (not possible) */
+     SQLITE_FLOAT,    /* 0x26 (not possible) */
+     SQLITE_NULL,     /* 0x27 (not possible) */
+     SQLITE_FLOAT,    /* 0x28 (not possible) */
+     SQLITE_NULL,     /* 0x29 (not possible) */
+     SQLITE_FLOAT,    /* 0x2a (not possible) */
+     SQLITE_NULL,     /* 0x2b (not possible) */
+     SQLITE_FLOAT,    /* 0x2c (not possible) */
+     SQLITE_NULL,     /* 0x2d (not possible) */
+     SQLITE_FLOAT,    /* 0x2e (not possible) */
+     SQLITE_NULL,     /* 0x2f (not possible) */
+     SQLITE_BLOB,     /* 0x30 (not possible) */
+     SQLITE_NULL,     /* 0x31 (not possible) */
+     SQLITE_TEXT,     /* 0x32 (not possible) */
+     SQLITE_NULL,     /* 0x33 (not possible) */
+     SQLITE_FLOAT,    /* 0x34 (not possible) */
+     SQLITE_NULL,     /* 0x35 (not possible) */
+     SQLITE_FLOAT,    /* 0x36 (not possible) */
+     SQLITE_NULL,     /* 0x37 (not possible) */
+     SQLITE_FLOAT,    /* 0x38 (not possible) */
+     SQLITE_NULL,     /* 0x39 (not possible) */
+     SQLITE_FLOAT,    /* 0x3a (not possible) */
+     SQLITE_NULL,     /* 0x3b (not possible) */
+     SQLITE_FLOAT,    /* 0x3c (not possible) */
+     SQLITE_NULL,     /* 0x3d (not possible) */
+     SQLITE_FLOAT,    /* 0x3e (not possible) */
+     SQLITE_NULL,     /* 0x3f (not possible) */
+  };
+#ifdef SQLITE_DEBUG
+  {
+    int eType = SQLITE_BLOB;
+    if( pVal->flags & MEM_Null ){
+      eType = SQLITE_NULL;
+    }else if( pVal->flags & (MEM_Real|MEM_IntReal) ){
+      eType = SQLITE_FLOAT;
+    }else if( pVal->flags & MEM_Int ){
+      eType = SQLITE_INTEGER;
+    }else if( pVal->flags & MEM_Str ){
+      eType = SQLITE_TEXT;
+    }
+    assert( eType == aType[pVal->flags&MEM_AffMask] );
+  }
+#endif
+  return aType[pVal->flags&MEM_AffMask];
+}
+SQLITE_API int sqlite3_value_encoding(sqlite3_value *pVal){
+  return pVal->enc;
+}
+
+/* Return true if a parameter to xUpdate represents an unchanged column */
+SQLITE_API int sqlite3_value_nochange(sqlite3_value *pVal){
+  return (pVal->flags&(MEM_Null|MEM_Zero))==(MEM_Null|MEM_Zero);
+}
+
+/* Return true if a parameter value originated from an sqlite3_bind() */
+SQLITE_API int sqlite3_value_frombind(sqlite3_value *pVal){
+  return (pVal->flags&MEM_FromBind)!=0;
+}
+
+/* Make a copy of an sqlite3_value object
+*/
+SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value *pOrig){
+  sqlite3_value *pNew;
+  if( pOrig==0 ) return 0;
+  pNew = sqlite3_malloc( sizeof(*pNew) );
+  if( pNew==0 ) return 0;
+  memset(pNew, 0, sizeof(*pNew));
+  memcpy(pNew, pOrig, MEMCELLSIZE);
+  pNew->flags &= ~MEM_Dyn;
+  pNew->db = 0;
+  if( pNew->flags&(MEM_Str|MEM_Blob) ){
+    pNew->flags &= ~(MEM_Static|MEM_Dyn);
+    pNew->flags |= MEM_Ephem;
+    if( sqlite3VdbeMemMakeWriteable(pNew)!=SQLITE_OK ){
+      sqlite3ValueFree(pNew);
+      pNew = 0;
+    }
+  }else if( pNew->flags & MEM_Null ){
+    /* Do not duplicate pointer values */
+    pNew->flags &= ~(MEM_Term|MEM_Subtype);
+  }
+  return pNew;
+}
+
+/* Destroy an sqlite3_value object previously obtained from
+** sqlite3_value_dup().
+*/
+SQLITE_API void sqlite3_value_free(sqlite3_value *pOld){
+  sqlite3ValueFree(pOld);
+}
+
+
+/**************************** sqlite3_result_  *******************************
+** The following routines are used by user-defined functions to specify
+** the function result.
+**
+** The setStrOrError() function calls sqlite3VdbeMemSetStr() to store the
+** result as a string or blob.  Appropriate errors are set if the string/blob
+** is too big or if an OOM occurs.
+**
+** The invokeValueDestructor(P,X) routine invokes destructor function X()
+** on value P if P is not going to be used and need to be destroyed.
+*/
+static void setResultStrOrError(
+  sqlite3_context *pCtx,  /* Function context */
+  const char *z,          /* String pointer */
+  int n,                  /* Bytes in string, or negative */
+  u8 enc,                 /* Encoding of z.  0 for BLOBs */
+  void (*xDel)(void*)     /* Destructor function */
+){
+  Mem *pOut = pCtx->pOut;
+  int rc = sqlite3VdbeMemSetStr(pOut, z, n, enc, xDel);
+  if( rc ){
+    if( rc==SQLITE_TOOBIG ){
+      sqlite3_result_error_toobig(pCtx);
+    }else{
+      /* The only errors possible from sqlite3VdbeMemSetStr are
+      ** SQLITE_TOOBIG and SQLITE_NOMEM */
+      assert( rc==SQLITE_NOMEM );
+      sqlite3_result_error_nomem(pCtx);
+    }
+    return;
+  }
+  sqlite3VdbeChangeEncoding(pOut, pCtx->enc);
+  if( sqlite3VdbeMemTooBig(pOut) ){
+    sqlite3_result_error_toobig(pCtx);
+  }
+}
+static int invokeValueDestructor(
+  const void *p,             /* Value to destroy */
+  void (*xDel)(void*),       /* The destructor */
+  sqlite3_context *pCtx      /* Set a SQLITE_TOOBIG error if not NULL */
+){
+  assert( xDel!=SQLITE_DYNAMIC );
+  if( xDel==0 ){
+    /* noop */
+  }else if( xDel==SQLITE_TRANSIENT ){
+    /* noop */
+  }else{
+    xDel((void*)p);
+  }
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx!=0 ){
+    sqlite3_result_error_toobig(pCtx);
+  }
+#else
+  assert( pCtx!=0 );
+  sqlite3_result_error_toobig(pCtx);
+#endif
+  return SQLITE_TOOBIG;
+}
+SQLITE_API void sqlite3_result_blob(
+  sqlite3_context *pCtx,
+  const void *z,
+  int n,
+  void (*xDel)(void *)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 || n<0 ){
+    invokeValueDestructor(z, xDel, pCtx);
+    return;
+  }
+#endif
+  assert( n>=0 );
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n, 0, xDel);
+}
+SQLITE_API void sqlite3_result_blob64(
+  sqlite3_context *pCtx,
+  const void *z,
+  sqlite3_uint64 n,
+  void (*xDel)(void *)
+){
+  assert( xDel!=SQLITE_DYNAMIC );
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ){
+    invokeValueDestructor(z, xDel, 0);
+    return;
+  }
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  if( n>0x7fffffff ){
+    (void)invokeValueDestructor(z, xDel, pCtx);
+  }else{
+    setResultStrOrError(pCtx, z, (int)n, 0, xDel);
+  }
+}
+SQLITE_API void sqlite3_result_double(sqlite3_context *pCtx, double rVal){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetDouble(pCtx->pOut, rVal);
+}
+SQLITE_API void sqlite3_result_error(sqlite3_context *pCtx, const char *z, int n){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  pCtx->isError = SQLITE_ERROR;
+  sqlite3VdbeMemSetStr(pCtx->pOut, z, n, SQLITE_UTF8, SQLITE_TRANSIENT);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API void sqlite3_result_error16(sqlite3_context *pCtx, const void *z, int n){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  pCtx->isError = SQLITE_ERROR;
+  sqlite3VdbeMemSetStr(pCtx->pOut, z, n, SQLITE_UTF16NATIVE, SQLITE_TRANSIENT);
+}
+#endif
+SQLITE_API void sqlite3_result_int(sqlite3_context *pCtx, int iVal){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetInt64(pCtx->pOut, (i64)iVal);
+}
+SQLITE_API void sqlite3_result_int64(sqlite3_context *pCtx, i64 iVal){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetInt64(pCtx->pOut, iVal);
+}
+SQLITE_API void sqlite3_result_null(sqlite3_context *pCtx){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetNull(pCtx->pOut);
+}
+SQLITE_API void sqlite3_result_pointer(
+  sqlite3_context *pCtx,
+  void *pPtr,
+  const char *zPType,
+  void (*xDestructor)(void*)
+){
+  Mem *pOut;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ){
+    invokeValueDestructor(pPtr, xDestructor, 0);
+    return;
+  }
+#endif
+  pOut = pCtx->pOut;
+  assert( sqlite3_mutex_held(pOut->db->mutex) );
+  sqlite3VdbeMemRelease(pOut);
+  pOut->flags = MEM_Null;
+  sqlite3VdbeMemSetPointer(pOut, pPtr, zPType, xDestructor);
+}
+SQLITE_API void sqlite3_result_subtype(sqlite3_context *pCtx, unsigned int eSubtype){
+  Mem *pOut;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+#if defined(SQLITE_STRICT_SUBTYPE) && SQLITE_STRICT_SUBTYPE+0!=0
+  if( pCtx->pFunc!=0
+   && (pCtx->pFunc->funcFlags & SQLITE_RESULT_SUBTYPE)==0
+  ){
+    char zErr[200];
+    sqlite3_snprintf(sizeof(zErr), zErr,
+                     "misuse of sqlite3_result_subtype() by %s()",
+                     pCtx->pFunc->zName);
+    sqlite3_result_error(pCtx, zErr, -1);
+    return;
+  }
+#endif /* SQLITE_STRICT_SUBTYPE */
+  pOut = pCtx->pOut;
+  assert( sqlite3_mutex_held(pOut->db->mutex) );
+  pOut->eSubtype = eSubtype & 0xff;
+  pOut->flags |= MEM_Subtype;
+}
+SQLITE_API void sqlite3_result_text(
+  sqlite3_context *pCtx,
+  const char *z,
+  int n,
+  void (*xDel)(void *)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ){
+    invokeValueDestructor(z, xDel, 0);
+    return;
+  }
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n, SQLITE_UTF8, xDel);
+}
+SQLITE_API void sqlite3_result_text64(
+  sqlite3_context *pCtx,
+  const char *z,
+  sqlite3_uint64 n,
+  void (*xDel)(void *),
+  unsigned char enc
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ){
+    invokeValueDestructor(z, xDel, 0);
+    return;
+  }
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  assert( xDel!=SQLITE_DYNAMIC );
+  if( enc!=SQLITE_UTF8 ){
+    if( enc==SQLITE_UTF16 ) enc = SQLITE_UTF16NATIVE;
+    n &= ~(u64)1;
+  }
+  if( n>0x7fffffff ){
+    (void)invokeValueDestructor(z, xDel, pCtx);
+  }else{
+    setResultStrOrError(pCtx, z, (int)n, enc, xDel);
+    sqlite3VdbeMemZeroTerminateIfAble(pCtx->pOut);
+  }
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API void sqlite3_result_text16(
+  sqlite3_context *pCtx,
+  const void *z,
+  int n,
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n & ~(u64)1, SQLITE_UTF16NATIVE, xDel);
+}
+SQLITE_API void sqlite3_result_text16be(
+  sqlite3_context *pCtx,
+  const void *z,
+  int n,
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n & ~(u64)1, SQLITE_UTF16BE, xDel);
+}
+SQLITE_API void sqlite3_result_text16le(
+  sqlite3_context *pCtx,
+  const void *z,
+  int n,
+  void (*xDel)(void *)
+){
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  setResultStrOrError(pCtx, z, n & ~(u64)1, SQLITE_UTF16LE, xDel);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API void sqlite3_result_value(sqlite3_context *pCtx, sqlite3_value *pValue){
+  Mem *pOut;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+  if( pValue==0 ){
+    sqlite3_result_null(pCtx);
+    return;
+  }
+#endif
+  pOut = pCtx->pOut;
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemCopy(pOut, pValue);
+  sqlite3VdbeChangeEncoding(pOut, pCtx->enc);
+  if( sqlite3VdbeMemTooBig(pOut) ){
+    sqlite3_result_error_toobig(pCtx);
+  }
+}
+SQLITE_API void sqlite3_result_zeroblob(sqlite3_context *pCtx, int n){
+  sqlite3_result_zeroblob64(pCtx, n>0 ? n : 0);
+}
+SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context *pCtx, u64 n){
+  Mem *pOut;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  pOut = pCtx->pOut;
+  assert( sqlite3_mutex_held(pOut->db->mutex) );
+  if( n>(u64)pOut->db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    sqlite3_result_error_toobig(pCtx);
+    return SQLITE_TOOBIG;
+  }
+#ifndef SQLITE_OMIT_INCRBLOB
+  sqlite3VdbeMemSetZeroBlob(pCtx->pOut, (int)n);
+  return SQLITE_OK;
+#else
+  return sqlite3VdbeMemSetZeroBlob(pCtx->pOut, (int)n);
+#endif
+}
+SQLITE_API void sqlite3_result_error_code(sqlite3_context *pCtx, int errCode){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  pCtx->isError = errCode ? errCode : -1;
+#ifdef SQLITE_DEBUG
+  if( pCtx->pVdbe ) pCtx->pVdbe->rcApp = errCode;
+#endif
+  if( pCtx->pOut->flags & MEM_Null ){
+    setResultStrOrError(pCtx, sqlite3ErrStr(errCode), -1, SQLITE_UTF8,
+                        SQLITE_STATIC);
+  }
+}
+
+/* Force an SQLITE_TOOBIG error. */
+SQLITE_API void sqlite3_result_error_toobig(sqlite3_context *pCtx){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  pCtx->isError = SQLITE_TOOBIG;
+  sqlite3VdbeMemSetStr(pCtx->pOut, "string or blob too big", -1,
+                       SQLITE_UTF8, SQLITE_STATIC);
+}
+
+/* An SQLITE_NOMEM error. */
+SQLITE_API void sqlite3_result_error_nomem(sqlite3_context *pCtx){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  sqlite3VdbeMemSetNull(pCtx->pOut);
+  pCtx->isError = SQLITE_NOMEM_BKPT;
+  sqlite3OomFault(pCtx->pOut->db);
+}
+
+#ifndef SQLITE_UNTESTABLE
+/* Force the INT64 value currently stored as the result to be
+** a MEM_IntReal value.  See the SQLITE_TESTCTRL_RESULT_INTREAL
+** test-control.
+*/
+SQLITE_PRIVATE void sqlite3ResultIntReal(sqlite3_context *pCtx){
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+  if( pCtx->pOut->flags & MEM_Int ){
+    pCtx->pOut->flags &= ~MEM_Int;
+    pCtx->pOut->flags |= MEM_IntReal;
+  }
+}
+#endif
+
+
+/*
+** This function is called after a transaction has been committed. It
+** invokes callbacks registered with sqlite3_wal_hook() as required.
+*/
+static int doWalCallbacks(sqlite3 *db){
+  int rc = SQLITE_OK;
+#ifndef SQLITE_OMIT_WAL
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      int nEntry;
+      sqlite3BtreeEnter(pBt);
+      nEntry = sqlite3PagerWalCallback(sqlite3BtreePager(pBt));
+      sqlite3BtreeLeave(pBt);
+      if( nEntry>0 && db->xWalCallback && rc==SQLITE_OK ){
+        rc = db->xWalCallback(db->pWalArg, db, db->aDb[i].zDbSName, nEntry);
+      }
+    }
+  }
+#endif
+  return rc;
+}
+
+
+/*
+** Execute the statement pStmt, either until a row of data is ready, the
+** statement is completely executed or an error occurs.
+**
+** This routine implements the bulk of the logic behind the sqlite_step()
+** API.  The only thing omitted is the automatic recompile if a
+** schema change has occurred.  That detail is handled by the
+** outer sqlite3_step() wrapper procedure.
+*/
+static int sqlite3Step(Vdbe *p){
+  sqlite3 *db;
+  int rc;
+
+  assert(p);
+  db = p->db;
+  if( p->eVdbeState!=VDBE_RUN_STATE ){
+    restart_step:
+    if( p->eVdbeState==VDBE_READY_STATE ){
+      if( p->expired ){
+        p->rc = SQLITE_SCHEMA;
+        rc = SQLITE_ERROR;
+        if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ){
+          /* If this statement was prepared using saved SQL and an
+          ** error has occurred, then return the error code in p->rc to the
+          ** caller. Set the error code in the database handle to the same
+          ** value.
+          */
+          rc = sqlite3VdbeTransferError(p);
+        }
+        goto end_of_step;
+      }
+
+      /* If there are no other statements currently running, then
+      ** reset the interrupt flag.  This prevents a call to sqlite3_interrupt
+      ** from interrupting a statement that has not yet started.
+      */
+      if( db->nVdbeActive==0 ){
+        AtomicStore(&db->u1.isInterrupted, 0);
+      }
+
+      assert( db->nVdbeWrite>0 || db->autoCommit==0
+          || ((db->nDeferredCons + db->nDeferredImmCons)==0)
+      );
+
+#ifndef SQLITE_OMIT_TRACE
+      if( (db->mTrace & (SQLITE_TRACE_PROFILE|SQLITE_TRACE_XPROFILE))!=0
+          && !db->init.busy && p->zSql ){
+        sqlite3OsCurrentTimeInt64(db->pVfs, &p->startTime);
+      }else{
+        assert( p->startTime==0 );
+      }
+#endif
+
+      db->nVdbeActive++;
+      if( p->readOnly==0 ) db->nVdbeWrite++;
+      if( p->bIsReader ) db->nVdbeRead++;
+      p->pc = 0;
+      p->eVdbeState = VDBE_RUN_STATE;
+    }else
+
+    if( ALWAYS(p->eVdbeState==VDBE_HALT_STATE) ){
+      /* We used to require that sqlite3_reset() be called before retrying
+      ** sqlite3_step() after any error or after SQLITE_DONE.  But beginning
+      ** with version 3.7.0, we changed this so that sqlite3_reset() would
+      ** be called automatically instead of throwing the SQLITE_MISUSE error.
+      ** This "automatic-reset" change is not technically an incompatibility,
+      ** since any application that receives an SQLITE_MISUSE is broken by
+      ** definition.
+      **
+      ** Nevertheless, some published applications that were originally written
+      ** for version 3.6.23 or earlier do in fact depend on SQLITE_MISUSE
+      ** returns, and those were broken by the automatic-reset change.  As a
+      ** a work-around, the SQLITE_OMIT_AUTORESET compile-time restores the
+      ** legacy behavior of returning SQLITE_MISUSE for cases where the
+      ** previous sqlite3_step() returned something other than a SQLITE_LOCKED
+      ** or SQLITE_BUSY error.
+      */
+#ifdef SQLITE_OMIT_AUTORESET
+      if( (rc = p->rc&0xff)==SQLITE_BUSY || rc==SQLITE_LOCKED ){
+        sqlite3_reset((sqlite3_stmt*)p);
+      }else{
+        return SQLITE_MISUSE_BKPT;
+      }
+#else
+      sqlite3_reset((sqlite3_stmt*)p);
+#endif
+      assert( p->eVdbeState==VDBE_READY_STATE );
+      goto restart_step;
+    }
+  }
+
+#ifdef SQLITE_DEBUG
+  p->rcApp = SQLITE_OK;
+#endif
+#ifndef SQLITE_OMIT_EXPLAIN
+  if( p->explain ){
+    rc = sqlite3VdbeList(p);
+  }else
+#endif /* SQLITE_OMIT_EXPLAIN */
+  {
+    db->nVdbeExec++;
+    rc = sqlite3VdbeExec(p);
+    db->nVdbeExec--;
+  }
+
+  if( rc==SQLITE_ROW ){
+    assert( p->rc==SQLITE_OK );
+    assert( db->mallocFailed==0 );
+    db->errCode = SQLITE_ROW;
+    return SQLITE_ROW;
+  }else{
+#ifndef SQLITE_OMIT_TRACE
+    /* If the statement completed successfully, invoke the profile callback */
+    checkProfileCallback(db, p);
+#endif
+    p->pResultRow = 0;
+    if( rc==SQLITE_DONE && db->autoCommit ){
+      assert( p->rc==SQLITE_OK );
+      p->rc = doWalCallbacks(db);
+      if( p->rc!=SQLITE_OK ){
+        rc = SQLITE_ERROR;
+      }
+    }else if( rc!=SQLITE_DONE && (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ){
+      /* If this statement was prepared using saved SQL and an
+      ** error has occurred, then return the error code in p->rc to the
+      ** caller. Set the error code in the database handle to the same value.
+      */
+      rc = sqlite3VdbeTransferError(p);
+    }
+  }
+
+  db->errCode = rc;
+  if( SQLITE_NOMEM==sqlite3ApiExit(p->db, p->rc) ){
+    p->rc = SQLITE_NOMEM_BKPT;
+    if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ) rc = p->rc;
+  }
+end_of_step:
+  /* There are only a limited number of result codes allowed from the
+  ** statements prepared using the legacy sqlite3_prepare() interface */
+  assert( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0
+       || rc==SQLITE_ROW  || rc==SQLITE_DONE   || rc==SQLITE_ERROR
+       || (rc&0xff)==SQLITE_BUSY || rc==SQLITE_MISUSE
+  );
+  return (rc&db->errMask);
+}
+
+/*
+** This is the top-level implementation of sqlite3_step().  Call
+** sqlite3Step() to do most of the work.  If a schema error occurs,
+** call sqlite3Reprepare() and try again.
+*/
+SQLITE_API int sqlite3_step(sqlite3_stmt *pStmt){
+  int rc = SQLITE_OK;      /* Result from sqlite3Step() */
+  Vdbe *v = (Vdbe*)pStmt;  /* the prepared statement */
+  int cnt = 0;             /* Counter to prevent infinite loop of reprepares */
+  sqlite3 *db;             /* The database connection */
+
+  if( vdbeSafetyNotNull(v) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  db = v->db;
+  sqlite3_mutex_enter(db->mutex);
+  while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
+         && cnt++ < SQLITE_MAX_SCHEMA_RETRY ){
+    int savedPc = v->pc;
+    rc = sqlite3Reprepare(v);
+    if( rc!=SQLITE_OK ){
+      /* This case occurs after failing to recompile an sql statement.
+      ** The error message from the SQL compiler has already been loaded
+      ** into the database handle. This block copies the error message
+      ** from the database handle into the statement and sets the statement
+      ** program counter to 0 to ensure that when the statement is
+      ** finalized or reset the parser error message is available via
+      ** sqlite3_errmsg() and sqlite3_errcode().
+      */
+      const char *zErr = (const char *)sqlite3_value_text(db->pErr);
+      sqlite3DbFree(db, v->zErrMsg);
+      if( !db->mallocFailed ){
+        v->zErrMsg = sqlite3DbStrDup(db, zErr);
+        v->rc = rc = sqlite3ApiExit(db, rc);
+      } else {
+        v->zErrMsg = 0;
+        v->rc = rc = SQLITE_NOMEM_BKPT;
+      }
+      break;
+    }
+    sqlite3_reset(pStmt);
+    if( savedPc>=0 ){
+      /* Setting minWriteFileFormat to 254 is a signal to the OP_Init and
+      ** OP_Trace opcodes to *not* perform SQLITE_TRACE_STMT because it has
+      ** already been done once on a prior invocation that failed due to
+      ** SQLITE_SCHEMA.   tag-20220401a  */
+      v->minWriteFileFormat = 254;
+    }
+    assert( v->expired==0 );
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+
+/*
+** Extract the user data from a sqlite3_context structure and return a
+** pointer to it.
+*/
+SQLITE_API void *sqlite3_user_data(sqlite3_context *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return 0;
+#endif
+  assert( p && p->pFunc );
+  return p->pFunc->pUserData;
+}
+
+/*
+** Extract the user data from a sqlite3_context structure and return a
+** pointer to it.
+**
+** IMPLEMENTATION-OF: R-46798-50301 The sqlite3_context_db_handle() interface
+** returns a copy of the pointer to the database connection (the 1st
+** parameter) of the sqlite3_create_function() and
+** sqlite3_create_function16() routines that originally registered the
+** application defined function.
+*/
+SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return 0;
+#else
+  assert( p && p->pOut );
+#endif
+  return p->pOut->db;
+}
+
+/*
+** If this routine is invoked from within an xColumn method of a virtual
+** table, then it returns true if and only if the the call is during an
+** UPDATE operation and the value of the column will not be modified
+** by the UPDATE.
+**
+** If this routine is called from any context other than within the
+** xColumn method of a virtual table, then the return value is meaningless
+** and arbitrary.
+**
+** Virtual table implements might use this routine to optimize their
+** performance by substituting a NULL result, or some other light-weight
+** value, as a signal to the xUpdate routine that the column is unchanged.
+*/
+SQLITE_API int sqlite3_vtab_nochange(sqlite3_context *p){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return 0;
+#else
+  assert( p );
+#endif
+  return sqlite3_value_nochange(p->pOut);
+}
+
+/*
+** The destructor function for a ValueList object.  This needs to be
+** a separate function, unknowable to the application, to ensure that
+** calls to sqlite3_vtab_in_first()/sqlite3_vtab_in_next() that are not
+** preceded by activation of IN processing via sqlite3_vtab_int() do not
+** try to access a fake ValueList object inserted by a hostile extension.
+*/
+SQLITE_PRIVATE void sqlite3VdbeValueListFree(void *pToDelete){
+  sqlite3_free(pToDelete);
+}
+
+/*
+** Implementation of sqlite3_vtab_in_first() (if bNext==0) and
+** sqlite3_vtab_in_next() (if bNext!=0).
+*/
+static int valueFromValueList(
+  sqlite3_value *pVal,        /* Pointer to the ValueList object */
+  sqlite3_value **ppOut,      /* Store the next value from the list here */
+  int bNext                   /* 1 for _next(). 0 for _first() */
+){
+  int rc;
+  ValueList *pRhs;
+
+  *ppOut = 0;
+  if( pVal==0 ) return SQLITE_MISUSE_BKPT;
+  if( (pVal->flags & MEM_Dyn)==0 || pVal->xDel!=sqlite3VdbeValueListFree ){
+    return SQLITE_ERROR;
+  }else{
+    assert( (pVal->flags&(MEM_TypeMask|MEM_Term|MEM_Subtype)) ==
+                 (MEM_Null|MEM_Term|MEM_Subtype) );
+    assert( pVal->eSubtype=='p' );
+    assert( pVal->u.zPType!=0 && strcmp(pVal->u.zPType,"ValueList")==0 );
+    pRhs = (ValueList*)pVal->z;
+  }
+  if( bNext ){
+    rc = sqlite3BtreeNext(pRhs->pCsr, 0);
+  }else{
+    int dummy = 0;
+    rc = sqlite3BtreeFirst(pRhs->pCsr, &dummy);
+    assert( rc==SQLITE_OK || sqlite3BtreeEof(pRhs->pCsr) );
+    if( sqlite3BtreeEof(pRhs->pCsr) ) rc = SQLITE_DONE;
+  }
+  if( rc==SQLITE_OK ){
+    u32 sz;       /* Size of current row in bytes */
+    Mem sMem;     /* Raw content of current row */
+    memset(&sMem, 0, sizeof(sMem));
+    sz = sqlite3BtreePayloadSize(pRhs->pCsr);
+    rc = sqlite3VdbeMemFromBtreeZeroOffset(pRhs->pCsr,(int)sz,&sMem);
+    if( rc==SQLITE_OK ){
+      u8 *zBuf = (u8*)sMem.z;
+      u32 iSerial;
+      sqlite3_value *pOut = pRhs->pOut;
+      int iOff = 1 + getVarint32(&zBuf[1], iSerial);
+      sqlite3VdbeSerialGet(&zBuf[iOff], iSerial, pOut);
+      pOut->enc = ENC(pOut->db);
+      if( (pOut->flags & MEM_Ephem)!=0 && sqlite3VdbeMemMakeWriteable(pOut) ){
+        rc = SQLITE_NOMEM;
+      }else{
+        *ppOut = pOut;
+      }
+    }
+    sqlite3VdbeMemRelease(&sMem);
+  }
+  return rc;
+}
+
+/*
+** Set the iterator value pVal to point to the first value in the set.
+** Set (*ppOut) to point to this value before returning.
+*/
+SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut){
+  return valueFromValueList(pVal, ppOut, 0);
+}
+
+/*
+** Set the iterator value pVal to point to the next value in the set.
+** Set (*ppOut) to point to this value before returning.
+*/
+SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut){
+  return valueFromValueList(pVal, ppOut, 1);
+}
+
+/*
+** Return the current time for a statement.  If the current time
+** is requested more than once within the same run of a single prepared
+** statement, the exact same time is returned for each invocation regardless
+** of the amount of time that elapses between invocations.  In other words,
+** the time returned is always the time of the first call.
+*/
+SQLITE_PRIVATE sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context *p){
+  int rc;
+#ifndef SQLITE_ENABLE_STAT4
+  sqlite3_int64 *piTime = &p->pVdbe->iCurrentTime;
+  assert( p->pVdbe!=0 );
+#else
+  sqlite3_int64 iTime = 0;
+  sqlite3_int64 *piTime = p->pVdbe!=0 ? &p->pVdbe->iCurrentTime : &iTime;
+#endif
+  if( *piTime==0 ){
+    rc = sqlite3OsCurrentTimeInt64(p->pOut->db->pVfs, piTime);
+    if( rc ) *piTime = 0;
+  }
+  return *piTime;
+}
+
+/*
+** Create a new aggregate context for p and return a pointer to
+** its pMem->z element.
+*/
+static SQLITE_NOINLINE void *createAggContext(sqlite3_context *p, int nByte){
+  Mem *pMem = p->pMem;
+  assert( (pMem->flags & MEM_Agg)==0 );
+  if( nByte<=0 ){
+    sqlite3VdbeMemSetNull(pMem);
+    pMem->z = 0;
+  }else{
+    sqlite3VdbeMemClearAndResize(pMem, nByte);
+    pMem->flags = MEM_Agg;
+    pMem->u.pDef = p->pFunc;
+    if( pMem->z ){
+      memset(pMem->z, 0, nByte);
+    }
+  }
+  return (void*)pMem->z;
+}
+
+/*
+** Allocate or return the aggregate context for a user function.  A new
+** context is allocated on the first call.  Subsequent calls return the
+** same context that was returned on prior calls.
+*/
+SQLITE_API void *sqlite3_aggregate_context(sqlite3_context *p, int nByte){
+  assert( p && p->pFunc && p->pFunc->xFinalize );
+  assert( sqlite3_mutex_held(p->pOut->db->mutex) );
+  testcase( nByte<0 );
+  if( (p->pMem->flags & MEM_Agg)==0 ){
+    return createAggContext(p, nByte);
+  }else{
+    return (void*)p->pMem->z;
+  }
+}
+
+/*
+** Return the auxiliary data pointer, if any, for the iArg'th argument to
+** the user-function defined by pCtx.
+**
+** The left-most argument is 0.
+**
+** Undocumented behavior:  If iArg is negative then access a cache of
+** auxiliary data pointers that is available to all functions within a
+** single prepared statement.  The iArg values must match.
+*/
+SQLITE_API void *sqlite3_get_auxdata(sqlite3_context *pCtx, int iArg){
+  AuxData *pAuxData;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return 0;
+#endif
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+#if SQLITE_ENABLE_STAT4
+  if( pCtx->pVdbe==0 ) return 0;
+#else
+  assert( pCtx->pVdbe!=0 );
+#endif
+  for(pAuxData=pCtx->pVdbe->pAuxData; pAuxData; pAuxData=pAuxData->pNextAux){
+    if(  pAuxData->iAuxArg==iArg && (pAuxData->iAuxOp==pCtx->iOp || iArg<0) ){
+      return pAuxData->pAux;
+    }
+  }
+  return 0;
+}
+
+/*
+** Set the auxiliary data pointer and delete function, for the iArg'th
+** argument to the user-function defined by pCtx. Any previous value is
+** deleted by calling the delete function specified when it was set.
+**
+** The left-most argument is 0.
+**
+** Undocumented behavior:  If iArg is negative then make the data available
+** to all functions within the current prepared statement using iArg as an
+** access code.
+*/
+SQLITE_API void sqlite3_set_auxdata(
+  sqlite3_context *pCtx,
+  int iArg,
+  void *pAux,
+  void (*xDelete)(void*)
+){
+  AuxData *pAuxData;
+  Vdbe *pVdbe;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pCtx==0 ) return;
+#endif
+  pVdbe= pCtx->pVdbe;
+  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
+#ifdef SQLITE_ENABLE_STAT4
+  if( pVdbe==0 ) goto failed;
+#else
+  assert( pVdbe!=0 );
+#endif
+
+  for(pAuxData=pVdbe->pAuxData; pAuxData; pAuxData=pAuxData->pNextAux){
+    if( pAuxData->iAuxArg==iArg && (pAuxData->iAuxOp==pCtx->iOp || iArg<0) ){
+      break;
+    }
+  }
+  if( pAuxData==0 ){
+    pAuxData = sqlite3DbMallocZero(pVdbe->db, sizeof(AuxData));
+    if( !pAuxData ) goto failed;
+    pAuxData->iAuxOp = pCtx->iOp;
+    pAuxData->iAuxArg = iArg;
+    pAuxData->pNextAux = pVdbe->pAuxData;
+    pVdbe->pAuxData = pAuxData;
+    if( pCtx->isError==0 ) pCtx->isError = -1;
+  }else if( pAuxData->xDeleteAux ){
+    pAuxData->xDeleteAux(pAuxData->pAux);
+  }
+
+  pAuxData->pAux = pAux;
+  pAuxData->xDeleteAux = xDelete;
+  return;
+
+failed:
+  if( xDelete ){
+    xDelete(pAux);
+  }
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Return the number of times the Step function of an aggregate has been
+** called.
+**
+** This function is deprecated.  Do not use it for new code.  It is
+** provide only to avoid breaking legacy code.  New aggregate function
+** implementations should keep their own counts within their aggregate
+** context.
+*/
+SQLITE_API int sqlite3_aggregate_count(sqlite3_context *p){
+  assert( p && p->pMem && p->pFunc && p->pFunc->xFinalize );
+  return p->pMem->n;
+}
+#endif
+
+/*
+** Return the number of columns in the result set for the statement pStmt.
+*/
+SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt){
+  Vdbe *pVm = (Vdbe *)pStmt;
+  if( pVm==0 ) return 0;
+  return pVm->nResColumn;
+}
+
+/*
+** Return the number of values available from the current row of the
+** currently executing statement pStmt.
+*/
+SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt){
+  Vdbe *pVm = (Vdbe *)pStmt;
+  if( pVm==0 || pVm->pResultRow==0 ) return 0;
+  return pVm->nResColumn;
+}
+
+/*
+** Return a pointer to static memory containing an SQL NULL value.
+*/
+static const Mem *columnNullValue(void){
+  /* Even though the Mem structure contains an element
+  ** of type i64, on certain architectures (x86) with certain compiler
+  ** switches (-Os), gcc may align this Mem object on a 4-byte boundary
+  ** instead of an 8-byte one. This all works fine, except that when
+  ** running with SQLITE_DEBUG defined the SQLite code sometimes assert()s
+  ** that a Mem structure is located on an 8-byte boundary. To prevent
+  ** these assert()s from failing, when building with SQLITE_DEBUG defined
+  ** using gcc, we force nullMem to be 8-byte aligned using the magical
+  ** __attribute__((aligned(8))) macro.  */
+  static const Mem nullMem
+#if defined(SQLITE_DEBUG) && defined(__GNUC__)
+    __attribute__((aligned(8)))
+#endif
+    = {
+        /* .u          = */ {0},
+        /* .z          = */ (char*)0,
+        /* .n          = */ (int)0,
+        /* .flags      = */ (u16)MEM_Null,
+        /* .enc        = */ (u8)0,
+        /* .eSubtype   = */ (u8)0,
+        /* .db         = */ (sqlite3*)0,
+        /* .szMalloc   = */ (int)0,
+        /* .uTemp      = */ (u32)0,
+        /* .zMalloc    = */ (char*)0,
+        /* .xDel       = */ (void(*)(void*))0,
+#ifdef SQLITE_DEBUG
+        /* .pScopyFrom = */ (Mem*)0,
+        /* .mScopyFlags= */ 0,
+        /* .bScopy     = */ 0,
+#endif
+      };
+  return &nullMem;
+}
+
+/*
+** Check to see if column iCol of the given statement is valid.  If
+** it is, return a pointer to the Mem for the value of that column.
+** If iCol is not valid, return a pointer to a Mem which has a value
+** of NULL.
+*/
+static Mem *columnMem(sqlite3_stmt *pStmt, int i){
+  Vdbe *pVm;
+  Mem *pOut;
+
+  pVm = (Vdbe *)pStmt;
+  if( pVm==0 ) return (Mem*)columnNullValue();
+  assert( pVm->db );
+  sqlite3_mutex_enter(pVm->db->mutex);
+  if( pVm->pResultRow!=0 && i<pVm->nResColumn && i>=0 ){
+    pOut = &pVm->pResultRow[i];
+  }else{
+    sqlite3Error(pVm->db, SQLITE_RANGE);
+    pOut = (Mem*)columnNullValue();
+  }
+  return pOut;
+}
+
+/*
+** This function is called after invoking an sqlite3_value_XXX function on a
+** column value (i.e. a value returned by evaluating an SQL expression in the
+** select list of a SELECT statement) that may cause a malloc() failure. If
+** malloc() has failed, the threads mallocFailed flag is cleared and the result
+** code of statement pStmt set to SQLITE_NOMEM.
+**
+** Specifically, this is called from within:
+**
+**     sqlite3_column_int()
+**     sqlite3_column_int64()
+**     sqlite3_column_text()
+**     sqlite3_column_text16()
+**     sqlite3_column_double()
+**     sqlite3_column_bytes()
+**     sqlite3_column_bytes16()
+**     sqlite3_column_blob()
+*/
+static void columnMallocFailure(sqlite3_stmt *pStmt)
+{
+  /* If malloc() failed during an encoding conversion within an
+  ** sqlite3_column_XXX API, then set the return code of the statement to
+  ** SQLITE_NOMEM. The next call to _step() (if any) will return SQLITE_ERROR
+  ** and _finalize() will return NOMEM.
+  */
+  Vdbe *p = (Vdbe *)pStmt;
+  if( p ){
+    assert( p->db!=0 );
+    assert( sqlite3_mutex_held(p->db->mutex) );
+    p->rc = sqlite3ApiExit(p->db, p->rc);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+}
+
+/**************************** sqlite3_column_  *******************************
+** The following routines are used to access elements of the current row
+** in the result set.
+*/
+SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt *pStmt, int i){
+  const void *val;
+  val = sqlite3_value_blob( columnMem(pStmt,i) );
+  /* Even though there is no encoding conversion, value_blob() might
+  ** need to call malloc() to expand the result of a zeroblob()
+  ** expression.
+  */
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API int sqlite3_column_bytes(sqlite3_stmt *pStmt, int i){
+  int val = sqlite3_value_bytes( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt *pStmt, int i){
+  int val = sqlite3_value_bytes16( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API double sqlite3_column_double(sqlite3_stmt *pStmt, int i){
+  double val = sqlite3_value_double( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API int sqlite3_column_int(sqlite3_stmt *pStmt, int i){
+  int val = sqlite3_value_int( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API sqlite_int64 sqlite3_column_int64(sqlite3_stmt *pStmt, int i){
+  sqlite_int64 val = sqlite3_value_int64( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt *pStmt, int i){
+  const unsigned char *val = sqlite3_value_text( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt *pStmt, int i){
+  Mem *pOut = columnMem(pStmt, i);
+  if( pOut->flags&MEM_Static ){
+    pOut->flags &= ~MEM_Static;
+    pOut->flags |= MEM_Ephem;
+  }
+  columnMallocFailure(pStmt);
+  return (sqlite3_value *)pOut;
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt *pStmt, int i){
+  const void *val = sqlite3_value_text16( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return val;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API int sqlite3_column_type(sqlite3_stmt *pStmt, int i){
+  int iType = sqlite3_value_type( columnMem(pStmt,i) );
+  columnMallocFailure(pStmt);
+  return iType;
+}
+
+/*
+** Column names appropriate for EXPLAIN or EXPLAIN QUERY PLAN.
+*/
+static const char * const azExplainColNames8[] = {
+   "addr", "opcode", "p1", "p2", "p3", "p4", "p5", "comment",  /* EXPLAIN */
+   "id", "parent", "notused", "detail"                         /* EQP */
+};
+static const u16 azExplainColNames16data[] = {
+  /*   0 */  'a', 'd', 'd', 'r',                0,
+  /*   5 */  'o', 'p', 'c', 'o', 'd', 'e',      0,
+  /*  12 */  'p', '1',                          0,
+  /*  15 */  'p', '2',                          0,
+  /*  18 */  'p', '3',                          0,
+  /*  21 */  'p', '4',                          0,
+  /*  24 */  'p', '5',                          0,
+  /*  27 */  'c', 'o', 'm', 'm', 'e', 'n', 't', 0,
+  /*  35 */  'i', 'd',                          0,
+  /*  38 */  'p', 'a', 'r', 'e', 'n', 't',      0,
+  /*  45 */  'n', 'o', 't', 'u', 's', 'e', 'd', 0,
+  /*  53 */  'd', 'e', 't', 'a', 'i', 'l',      0
+};
+static const u8 iExplainColNames16[] = {
+  0, 5, 12, 15, 18, 21, 24, 27,
+  35, 38, 45, 53
+};
+
+/*
+** Convert the N-th element of pStmt->pColName[] into a string using
+** xFunc() then return that string.  If N is out of range, return 0.
+**
+** There are up to 5 names for each column.  useType determines which
+** name is returned.  Here are the names:
+**
+**    0      The column name as it should be displayed for output
+**    1      The datatype name for the column
+**    2      The name of the database that the column derives from
+**    3      The name of the table that the column derives from
+**    4      The name of the table column that the result column derives from
+**
+** If the result is not a simple column reference (if it is an expression
+** or a constant) then useTypes 2, 3, and 4 return NULL.
+*/
+static const void *columnName(
+  sqlite3_stmt *pStmt,     /* The statement */
+  int N,                   /* Which column to get the name for */
+  int useUtf16,            /* True to return the name as UTF16 */
+  int useType              /* What type of name */
+){
+  const void *ret;
+  Vdbe *p;
+  int n;
+  sqlite3 *db;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pStmt==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  if( N<0 ) return 0;
+  ret = 0;
+  p = (Vdbe *)pStmt;
+  db = p->db;
+  assert( db!=0 );
+  sqlite3_mutex_enter(db->mutex);
+
+  if( p->explain ){
+    if( useType>0 ) goto columnName_end;
+    n = p->explain==1 ? 8 : 4;
+    if( N>=n ) goto columnName_end;
+    if( useUtf16 ){
+      int i = iExplainColNames16[N + 8*p->explain - 8];
+      ret = (void*)&azExplainColNames16data[i];
+    }else{
+      ret = (void*)azExplainColNames8[N + 8*p->explain - 8];
+    }
+    goto columnName_end;
+  }
+  n = p->nResColumn;
+  if( N<n ){
+    u8 prior_mallocFailed = db->mallocFailed;
+    N += useType*n;
+#ifndef SQLITE_OMIT_UTF16
+    if( useUtf16 ){
+      ret = sqlite3_value_text16((sqlite3_value*)&p->aColName[N]);
+    }else
+#endif
+    {
+      ret = sqlite3_value_text((sqlite3_value*)&p->aColName[N]);
+    }
+    /* A malloc may have failed inside of the _text() call. If this
+    ** is the case, clear the mallocFailed flag and return NULL.
+    */
+    assert( db->mallocFailed==0 || db->mallocFailed==1 );
+    if( db->mallocFailed > prior_mallocFailed ){
+      sqlite3OomClear(db);
+      ret = 0;
+    }
+  }
+columnName_end:
+  sqlite3_mutex_leave(db->mutex);
+  return ret;
+}
+
+/*
+** Return the name of the Nth column of the result set returned by SQL
+** statement pStmt.
+*/
+SQLITE_API const char *sqlite3_column_name(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_NAME);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_NAME);
+}
+#endif
+
+/*
+** Constraint:  If you have ENABLE_COLUMN_METADATA then you must
+** not define OMIT_DECLTYPE.
+*/
+#if defined(SQLITE_OMIT_DECLTYPE) && defined(SQLITE_ENABLE_COLUMN_METADATA)
+# error "Must not define both SQLITE_OMIT_DECLTYPE \
+         and SQLITE_ENABLE_COLUMN_METADATA"
+#endif
+
+#ifndef SQLITE_OMIT_DECLTYPE
+/*
+** Return the column declaration type (if applicable) of the 'i'th column
+** of the result set of SQL statement pStmt.
+*/
+SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_DECLTYPE);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_DECLTYPE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+#endif /* SQLITE_OMIT_DECLTYPE */
+
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+/*
+** Return the name of the database from which a result column derives.
+** NULL is returned if the result column is an expression or constant or
+** anything else which is not an unambiguous reference to a database column.
+*/
+SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_DATABASE);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_DATABASE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Return the name of the table from which a result column derives.
+** NULL is returned if the result column is an expression or constant or
+** anything else which is not an unambiguous reference to a database column.
+*/
+SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_TABLE);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_TABLE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Return the name of the table column from which a result column derives.
+** NULL is returned if the result column is an expression or constant or
+** anything else which is not an unambiguous reference to a database column.
+*/
+SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 0, COLNAME_COLUMN);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt *pStmt, int N){
+  return columnName(pStmt, N, 1, COLNAME_COLUMN);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+#endif /* SQLITE_ENABLE_COLUMN_METADATA */
+
+
+/******************************* sqlite3_bind_  ***************************
+**
+** Routines used to attach values to wildcards in a compiled SQL statement.
+*/
+/*
+** Unbind the value bound to variable i in virtual machine p. This is the
+** the same as binding a NULL value to the column. If the "i" parameter is
+** out of range, then SQLITE_RANGE is returned. Otherwise SQLITE_OK.
+**
+** A successful evaluation of this routine acquires the mutex on p.
+** the mutex is released if any kind of error occurs.
+**
+** The error code stored in database p->db is overwritten with the return
+** value in any case.
+**
+** (tag-20240917-01) If  vdbeUnbind(p,(u32)(i-1))  returns SQLITE_OK,
+** that means all of the the following will be true:
+**
+**     p!=0
+**     p->pVar!=0
+**     i>0
+**     i<=p->nVar
+**
+** An assert() is normally added after vdbeUnbind() to help static analyzers
+** realize this.
+*/
+static int vdbeUnbind(Vdbe *p, unsigned int i){
+  Mem *pVar;
+  if( vdbeSafetyNotNull(p) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  sqlite3_mutex_enter(p->db->mutex);
+  if( p->eVdbeState!=VDBE_READY_STATE ){
+    sqlite3Error(p->db, SQLITE_MISUSE_BKPT);
+    sqlite3_mutex_leave(p->db->mutex);
+    sqlite3_log(SQLITE_MISUSE,
+        "bind on a busy prepared statement: [%s]", p->zSql);
+    return SQLITE_MISUSE_BKPT;
+  }
+  if( i>=(unsigned int)p->nVar ){
+    sqlite3Error(p->db, SQLITE_RANGE);
+    sqlite3_mutex_leave(p->db->mutex);
+    return SQLITE_RANGE;
+  }
+  pVar = &p->aVar[i];
+  sqlite3VdbeMemRelease(pVar);
+  pVar->flags = MEM_Null;
+  p->db->errCode = SQLITE_OK;
+
+  /* If the bit corresponding to this variable in Vdbe.expmask is set, then
+  ** binding a new value to this variable invalidates the current query plan.
+  **
+  ** IMPLEMENTATION-OF: R-57496-20354 If the specific value bound to a host
+  ** parameter in the WHERE clause might influence the choice of query plan
+  ** for a statement, then the statement will be automatically recompiled,
+  ** as if there had been a schema change, on the first sqlite3_step() call
+  ** following any change to the bindings of that parameter.
+  */
+  assert( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || p->expmask==0 );
+  if( p->expmask!=0 && (p->expmask & (i>=31 ? 0x80000000 : (u32)1<<i))!=0 ){
+    p->expired = 1;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Bind a text or BLOB value.
+*/
+static int bindText(
+  sqlite3_stmt *pStmt,   /* The statement to bind against */
+  int i,                 /* Index of the parameter to bind */
+  const void *zData,     /* Pointer to the data to be bound */
+  i64 nData,             /* Number of bytes of data to be bound */
+  void (*xDel)(void*),   /* Destructor for the data */
+  u8 encoding            /* Encoding for the data */
+){
+  Vdbe *p = (Vdbe *)pStmt;
+  Mem *pVar;
+  int rc;
+
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    if( zData!=0 ){
+      pVar = &p->aVar[i-1];
+      rc = sqlite3VdbeMemSetStr(pVar, zData, nData, encoding, xDel);
+      if( rc==SQLITE_OK && encoding!=0 ){
+        rc = sqlite3VdbeChangeEncoding(pVar, ENC(p->db));
+      }
+      if( rc ){
+        sqlite3Error(p->db, rc);
+        rc = sqlite3ApiExit(p->db, rc);
+      }
+    }
+    sqlite3_mutex_leave(p->db->mutex);
+  }else if( xDel!=SQLITE_STATIC && xDel!=SQLITE_TRANSIENT ){
+    xDel((void*)zData);
+  }
+  return rc;
+}
+
+
+/*
+** Bind a blob value to an SQL statement variable.
+*/
+SQLITE_API int sqlite3_bind_blob(
+  sqlite3_stmt *pStmt,
+  int i,
+  const void *zData,
+  int nData,
+  void (*xDel)(void*)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( nData<0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  return bindText(pStmt, i, zData, nData, xDel, 0);
+}
+SQLITE_API int sqlite3_bind_blob64(
+  sqlite3_stmt *pStmt,
+  int i,
+  const void *zData,
+  sqlite3_uint64 nData,
+  void (*xDel)(void*)
+){
+  assert( xDel!=SQLITE_DYNAMIC );
+  return bindText(pStmt, i, zData, nData, xDel, 0);
+}
+SQLITE_API int sqlite3_bind_double(sqlite3_stmt *pStmt, int i, double rValue){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    sqlite3VdbeMemSetDouble(&p->aVar[i-1], rValue);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_int(sqlite3_stmt *p, int i, int iValue){
+  return sqlite3_bind_int64(p, i, (i64)iValue);
+}
+SQLITE_API int sqlite3_bind_int64(sqlite3_stmt *pStmt, int i, sqlite_int64 iValue){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    sqlite3VdbeMemSetInt64(&p->aVar[i-1], iValue);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_null(sqlite3_stmt *pStmt, int i){
+  int rc;
+  Vdbe *p = (Vdbe*)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_pointer(
+  sqlite3_stmt *pStmt,
+  int i,
+  void *pPtr,
+  const char *zPTtype,
+  void (*xDestructor)(void*)
+){
+  int rc;
+  Vdbe *p = (Vdbe*)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+    sqlite3VdbeMemSetPointer(&p->aVar[i-1], pPtr, zPTtype, xDestructor);
+    sqlite3_mutex_leave(p->db->mutex);
+  }else if( xDestructor ){
+    xDestructor(pPtr);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_text(
+  sqlite3_stmt *pStmt,
+  int i,
+  const char *zData,
+  int nData,
+  void (*xDel)(void*)
+){
+  return bindText(pStmt, i, zData, nData, xDel, SQLITE_UTF8);
+}
+SQLITE_API int sqlite3_bind_text64(
+  sqlite3_stmt *pStmt,
+  int i,
+  const char *zData,
+  sqlite3_uint64 nData,
+  void (*xDel)(void*),
+  unsigned char enc
+){
+  assert( xDel!=SQLITE_DYNAMIC );
+  if( enc!=SQLITE_UTF8 ){
+    if( enc==SQLITE_UTF16 ) enc = SQLITE_UTF16NATIVE;
+    nData &= ~(u16)1;
+  }
+  return bindText(pStmt, i, zData, nData, xDel, enc);
+}
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API int sqlite3_bind_text16(
+  sqlite3_stmt *pStmt,
+  int i,
+  const void *zData,
+  int n,
+  void (*xDel)(void*)
+){
+  return bindText(pStmt, i, zData, n & ~(u64)1, xDel, SQLITE_UTF16NATIVE);
+}
+#endif /* SQLITE_OMIT_UTF16 */
+SQLITE_API int sqlite3_bind_value(sqlite3_stmt *pStmt, int i, const sqlite3_value *pValue){
+  int rc;
+  switch( sqlite3_value_type((sqlite3_value*)pValue) ){
+    case SQLITE_INTEGER: {
+      rc = sqlite3_bind_int64(pStmt, i, pValue->u.i);
+      break;
+    }
+    case SQLITE_FLOAT: {
+      assert( pValue->flags & (MEM_Real|MEM_IntReal) );
+      rc = sqlite3_bind_double(pStmt, i,
+          (pValue->flags & MEM_Real) ? pValue->u.r : (double)pValue->u.i
+      );
+      break;
+    }
+    case SQLITE_BLOB: {
+      if( pValue->flags & MEM_Zero ){
+        rc = sqlite3_bind_zeroblob(pStmt, i, pValue->u.nZero);
+      }else{
+        rc = sqlite3_bind_blob(pStmt, i, pValue->z, pValue->n,SQLITE_TRANSIENT);
+      }
+      break;
+    }
+    case SQLITE_TEXT: {
+      rc = bindText(pStmt,i,  pValue->z, pValue->n, SQLITE_TRANSIENT,
+                              pValue->enc);
+      break;
+    }
+    default: {
+      rc = sqlite3_bind_null(pStmt, i);
+      break;
+    }
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt *pStmt, int i, int n){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+  rc = vdbeUnbind(p, (u32)(i-1));
+  if( rc==SQLITE_OK ){
+    assert( p!=0 && p->aVar!=0 && i>0 && i<=p->nVar ); /* tag-20240917-01 */
+#ifndef SQLITE_OMIT_INCRBLOB
+    sqlite3VdbeMemSetZeroBlob(&p->aVar[i-1], n);
+#else
+    rc = sqlite3VdbeMemSetZeroBlob(&p->aVar[i-1], n);
+#endif
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return rc;
+}
+SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt *pStmt, int i, sqlite3_uint64 n){
+  int rc;
+  Vdbe *p = (Vdbe *)pStmt;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(p->db->mutex);
+  if( n>(u64)p->db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    rc = SQLITE_TOOBIG;
+  }else{
+    assert( (n & 0x7FFFFFFF)==n );
+    rc = sqlite3_bind_zeroblob(pStmt, i, n);
+  }
+  rc = sqlite3ApiExit(p->db, rc);
+  sqlite3_mutex_leave(p->db->mutex);
+  return rc;
+}
+
+/*
+** Return the number of wildcards that can be potentially bound to.
+** This routine is added to support DBD::SQLite.
+*/
+SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe*)pStmt;
+  return p ? p->nVar : 0;
+}
+
+/*
+** Return the name of a wildcard parameter.  Return NULL if the index
+** is out of range or if the wildcard is unnamed.
+**
+** The result is always UTF-8.
+*/
+SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt *pStmt, int i){
+  Vdbe *p = (Vdbe*)pStmt;
+  if( p==0 ) return 0;
+  return sqlite3VListNumToName(p->pVList, i);
+}
+
+/*
+** Given a wildcard parameter name, return the index of the variable
+** with that name.  If there is no variable with the given name,
+** return 0.
+*/
+SQLITE_PRIVATE int sqlite3VdbeParameterIndex(Vdbe *p, const char *zName, int nName){
+  if( p==0 || zName==0 ) return 0;
+  return sqlite3VListNameToNum(p->pVList, zName, nName);
+}
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt *pStmt, const char *zName){
+  return sqlite3VdbeParameterIndex((Vdbe*)pStmt, zName, sqlite3Strlen30(zName));
+}
+
+/*
+** Transfer all bindings from the first statement over to the second.
+*/
+SQLITE_PRIVATE int sqlite3TransferBindings(sqlite3_stmt *pFromStmt, sqlite3_stmt *pToStmt){
+  Vdbe *pFrom = (Vdbe*)pFromStmt;
+  Vdbe *pTo = (Vdbe*)pToStmt;
+  int i;
+  assert( pTo->db==pFrom->db );
+  assert( pTo->nVar==pFrom->nVar );
+  sqlite3_mutex_enter(pTo->db->mutex);
+  for(i=0; i<pFrom->nVar; i++){
+    sqlite3VdbeMemMove(&pTo->aVar[i], &pFrom->aVar[i]);
+  }
+  sqlite3_mutex_leave(pTo->db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Deprecated external interface.  Internal/core SQLite code
+** should call sqlite3TransferBindings.
+**
+** It is misuse to call this routine with statements from different
+** database connections.  But as this is a deprecated interface, we
+** will not bother to check for that condition.
+**
+** If the two statements contain a different number of bindings, then
+** an SQLITE_ERROR is returned.  Nothing else can go wrong, so otherwise
+** SQLITE_OK is returned.
+*/
+SQLITE_API int sqlite3_transfer_bindings(sqlite3_stmt *pFromStmt, sqlite3_stmt *pToStmt){
+  Vdbe *pFrom = (Vdbe*)pFromStmt;
+  Vdbe *pTo = (Vdbe*)pToStmt;
+  if( pFrom->nVar!=pTo->nVar ){
+    return SQLITE_ERROR;
+  }
+  assert( (pTo->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || pTo->expmask==0 );
+  if( pTo->expmask ){
+    pTo->expired = 1;
+  }
+  assert( (pFrom->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 || pFrom->expmask==0 );
+  if( pFrom->expmask ){
+    pFrom->expired = 1;
+  }
+  return sqlite3TransferBindings(pFromStmt, pToStmt);
+}
+#endif
+
+/*
+** Return the sqlite3* database handle to which the prepared statement given
+** in the argument belongs.  This is the same database handle that was
+** the first argument to the sqlite3_prepare() that was used to create
+** the statement in the first place.
+*/
+SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt *pStmt){
+  return pStmt ? ((Vdbe*)pStmt)->db : 0;
+}
+
+/*
+** Return true if the prepared statement is guaranteed to not modify the
+** database.
+*/
+SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt){
+  return pStmt ? ((Vdbe*)pStmt)->readOnly : 1;
+}
+
+/*
+** Return 1 if the statement is an EXPLAIN and return 2 if the
+** statement is an EXPLAIN QUERY PLAN
+*/
+SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt){
+  return pStmt ? ((Vdbe*)pStmt)->explain : 0;
+}
+
+/*
+** Set the explain mode for a statement.
+*/
+SQLITE_API int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode){
+  Vdbe *v = (Vdbe*)pStmt;
+  int rc;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( pStmt==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(v->db->mutex);
+  if( ((int)v->explain)==eMode ){
+    rc = SQLITE_OK;
+  }else if( eMode<0 || eMode>2 ){
+    rc = SQLITE_ERROR;
+  }else if( (v->prepFlags & SQLITE_PREPARE_SAVESQL)==0 ){
+    rc = SQLITE_ERROR;
+  }else if( v->eVdbeState!=VDBE_READY_STATE ){
+    rc = SQLITE_BUSY;
+  }else if( v->nMem>=10 && (eMode!=2 || v->haveEqpOps) ){
+    /* No reprepare necessary */
+    v->explain = eMode;
+    rc = SQLITE_OK;
+  }else{
+    v->explain = eMode;
+    rc = sqlite3Reprepare(v);
+    v->haveEqpOps = eMode==2;
+  }
+  if( v->explain ){
+    v->nResColumn = 12 - 4*v->explain;
+  }else{
+    v->nResColumn = v->nResAlloc;
+  }
+  sqlite3_mutex_leave(v->db->mutex);
+  return rc;
+}
+
+/*
+** Return true if the prepared statement is in need of being reset.
+*/
+SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt *pStmt){
+  Vdbe *v = (Vdbe*)pStmt;
+  return v!=0 && v->eVdbeState==VDBE_RUN_STATE;
+}
+
+/*
+** Return a pointer to the next prepared statement after pStmt associated
+** with database connection pDb.  If pStmt is NULL, return the first
+** prepared statement for the database connection.  Return NULL if there
+** are no more.
+*/
+SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt){
+  sqlite3_stmt *pNext;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(pDb) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(pDb->mutex);
+  if( pStmt==0 ){
+    pNext = (sqlite3_stmt*)pDb->pVdbe;
+  }else{
+    pNext = (sqlite3_stmt*)((Vdbe*)pStmt)->pVNext;
+  }
+  sqlite3_mutex_leave(pDb->mutex);
+  return pNext;
+}
+
+/*
+** Return the value of a status counter for a prepared statement
+*/
+SQLITE_API int sqlite3_stmt_status(sqlite3_stmt *pStmt, int op, int resetFlag){
+  Vdbe *pVdbe = (Vdbe*)pStmt;
+  u32 v;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !pStmt
+   || (op!=SQLITE_STMTSTATUS_MEMUSED && (op<0||op>=ArraySize(pVdbe->aCounter)))
+  ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  if( op==SQLITE_STMTSTATUS_MEMUSED ){
+    sqlite3 *db = pVdbe->db;
+    sqlite3_mutex_enter(db->mutex);
+    v = 0;
+    db->pnBytesFreed = (int*)&v;
+    assert( db->lookaside.pEnd==db->lookaside.pTrueEnd );
+    db->lookaside.pEnd = db->lookaside.pStart;
+    sqlite3VdbeDelete(pVdbe);
+    db->pnBytesFreed = 0;
+    db->lookaside.pEnd = db->lookaside.pTrueEnd;
+    sqlite3_mutex_leave(db->mutex);
+  }else{
+    v = pVdbe->aCounter[op];
+    if( resetFlag ) pVdbe->aCounter[op] = 0;
+  }
+  return (int)v;
+}
+
+/*
+** Return the SQL associated with a prepared statement
+*/
+SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe *)pStmt;
+  return p ? p->zSql : 0;
+}
+
+/*
+** Return the SQL associated with a prepared statement with
+** bound parameters expanded.  Space to hold the returned string is
+** obtained from sqlite3_malloc().  The caller is responsible for
+** freeing the returned string by passing it to sqlite3_free().
+**
+** The SQLITE_TRACE_SIZE_LIMIT puts an upper bound on the size of
+** expanded bound parameters.
+*/
+SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt){
+#ifdef SQLITE_OMIT_TRACE
+  return 0;
+#else
+  char *z = 0;
+  const char *zSql = sqlite3_sql(pStmt);
+  if( zSql ){
+    Vdbe *p = (Vdbe *)pStmt;
+    sqlite3_mutex_enter(p->db->mutex);
+    z = sqlite3VdbeExpandSql(p, zSql);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return z;
+#endif
+}
+
+#ifdef SQLITE_ENABLE_NORMALIZE
+/*
+** Return the normalized SQL associated with a prepared statement.
+*/
+SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe *)pStmt;
+  if( p==0 ) return 0;
+  if( p->zNormSql==0 && ALWAYS(p->zSql!=0) ){
+    sqlite3_mutex_enter(p->db->mutex);
+    p->zNormSql = sqlite3Normalize(p, p->zSql);
+    sqlite3_mutex_leave(p->db->mutex);
+  }
+  return p->zNormSql;
+}
+#endif /* SQLITE_ENABLE_NORMALIZE */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** Allocate and populate an UnpackedRecord structure based on the serialized
+** record in nKey/pKey. Return a pointer to the new UnpackedRecord structure
+** if successful, or a NULL pointer if an OOM error is encountered.
+*/
+static UnpackedRecord *vdbeUnpackRecord(
+  KeyInfo *pKeyInfo,
+  int nKey,
+  const void *pKey
+){
+  UnpackedRecord *pRet;           /* Return value */
+
+  pRet = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
+  if( pRet ){
+    memset(pRet->aMem, 0, sizeof(Mem)*(pKeyInfo->nKeyField+1));
+    sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, pRet);
+  }
+  return pRet;
+}
+
+/*
+** This function is called from within a pre-update callback to retrieve
+** a field of the row currently being updated or deleted.
+*/
+SQLITE_API int sqlite3_preupdate_old(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
+  PreUpdate *p;
+  Mem *pMem;
+  int rc = SQLITE_OK;
+  int iStore = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( db==0 || ppValue==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  p = db->pPreUpdate;
+  /* Test that this call is being made from within an SQLITE_DELETE or
+  ** SQLITE_UPDATE pre-update callback, and that iIdx is within range. */
+  if( !p || p->op==SQLITE_INSERT ){
+    rc = SQLITE_MISUSE_BKPT;
+    goto preupdate_old_out;
+  }
+  if( p->pPk ){
+    iStore = sqlite3TableColumnToIndex(p->pPk, iIdx);
+  }else{
+    iStore = sqlite3TableColumnToStorage(p->pTab, iIdx);
+  }
+  if( iStore>=p->pCsr->nField || iStore<0 ){
+    rc = SQLITE_RANGE;
+    goto preupdate_old_out;
+  }
+
+  if( iIdx==p->pTab->iPKey ){
+    *ppValue = pMem = &p->oldipk;
+    sqlite3VdbeMemSetInt64(pMem, p->iKey1);
+  }else{
+
+    /* If the old.* record has not yet been loaded into memory, do so now. */
+    if( p->pUnpacked==0 ){
+      u32 nRec;
+      u8 *aRec;
+
+      assert( p->pCsr->eCurType==CURTYPE_BTREE );
+      nRec = sqlite3BtreePayloadSize(p->pCsr->uc.pCursor);
+      aRec = sqlite3DbMallocRaw(db, nRec);
+      if( !aRec ) goto preupdate_old_out;
+      rc = sqlite3BtreePayload(p->pCsr->uc.pCursor, 0, nRec, aRec);
+      if( rc==SQLITE_OK ){
+        p->pUnpacked = vdbeUnpackRecord(&p->keyinfo, nRec, aRec);
+        if( !p->pUnpacked ) rc = SQLITE_NOMEM;
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3DbFree(db, aRec);
+        goto preupdate_old_out;
+      }
+      p->aRecord = aRec;
+    }
+
+    pMem = *ppValue = &p->pUnpacked->aMem[iStore];
+    if( iStore>=p->pUnpacked->nField ){
+      /* This occurs when the table has been extended using ALTER TABLE
+      ** ADD COLUMN. The value to return is the default value of the column. */
+      Column *pCol = &p->pTab->aCol[iIdx];
+      if( pCol->iDflt>0 ){
+        if( p->apDflt==0 ){
+          int nByte = sizeof(sqlite3_value*)*p->pTab->nCol;
+          p->apDflt = (sqlite3_value**)sqlite3DbMallocZero(db, nByte);
+          if( p->apDflt==0 ) goto preupdate_old_out;
+        }
+        if( p->apDflt[iIdx]==0 ){
+          sqlite3_value *pVal = 0;
+          Expr *pDflt;
+          assert( p->pTab!=0 && IsOrdinaryTable(p->pTab) );
+          pDflt = p->pTab->u.tab.pDfltList->a[pCol->iDflt-1].pExpr;
+          rc = sqlite3ValueFromExpr(db, pDflt, ENC(db), pCol->affinity, &pVal);
+          if( rc==SQLITE_OK && pVal==0 ){
+            rc = SQLITE_CORRUPT_BKPT;
+          }
+          p->apDflt[iIdx] = pVal;
+        }
+        *ppValue = p->apDflt[iIdx];
+      }else{
+        *ppValue = (sqlite3_value *)columnNullValue();
+      }
+    }else if( p->pTab->aCol[iIdx].affinity==SQLITE_AFF_REAL ){
+      if( pMem->flags & (MEM_Int|MEM_IntReal) ){
+        testcase( pMem->flags & MEM_Int );
+        testcase( pMem->flags & MEM_IntReal );
+        sqlite3VdbeMemRealify(pMem);
+      }
+    }
+  }
+
+ preupdate_old_out:
+  sqlite3Error(db, rc);
+  return sqlite3ApiExit(db, rc);
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** This function is called from within a pre-update callback to retrieve
+** the number of columns in the row being updated, deleted or inserted.
+*/
+SQLITE_API int sqlite3_preupdate_count(sqlite3 *db){
+  PreUpdate *p;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  p = db!=0 ? db->pPreUpdate : 0;
+#else
+  p = db->pPreUpdate;
+#endif
+  return (p ? p->keyinfo.nKeyField : 0);
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** This function is designed to be called from within a pre-update callback
+** only. It returns zero if the change that caused the callback was made
+** immediately by a user SQL statement. Or, if the change was made by a
+** trigger program, it returns the number of trigger programs currently
+** on the stack (1 for a top-level trigger, 2 for a trigger fired by a
+** top-level trigger etc.).
+**
+** For the purposes of the previous paragraph, a foreign key CASCADE, SET NULL
+** or SET DEFAULT action is considered a trigger.
+*/
+SQLITE_API int sqlite3_preupdate_depth(sqlite3 *db){
+  PreUpdate *p;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  p = db!=0 ? db->pPreUpdate : 0;
+#else
+  p = db->pPreUpdate;
+#endif
+  return (p ? p->v->nFrame : 0);
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** This function is designed to be called from within a pre-update callback
+** only.
+*/
+SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *db){
+  PreUpdate *p;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  p = db!=0 ? db->pPreUpdate : 0;
+#else
+  p = db->pPreUpdate;
+#endif
+  return (p ? p->iBlobWrite : -1);
+}
+#endif
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** This function is called from within a pre-update callback to retrieve
+** a field of the row currently being updated or inserted.
+*/
+SQLITE_API int sqlite3_preupdate_new(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
+  PreUpdate *p;
+  int rc = SQLITE_OK;
+  Mem *pMem;
+  int iStore = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( db==0 || ppValue==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  p = db->pPreUpdate;
+  if( !p || p->op==SQLITE_DELETE ){
+    rc = SQLITE_MISUSE_BKPT;
+    goto preupdate_new_out;
+  }
+  if( p->pPk && p->op!=SQLITE_UPDATE ){
+    iStore = sqlite3TableColumnToIndex(p->pPk, iIdx);
+  }else{
+    iStore = sqlite3TableColumnToStorage(p->pTab, iIdx);
+  }
+
+  if( iStore>=p->pCsr->nField || iStore<0 ){
+    rc = SQLITE_RANGE;
+    goto preupdate_new_out;
+  }
+
+  if( p->op==SQLITE_INSERT ){
+    /* For an INSERT, memory cell p->iNewReg contains the serialized record
+    ** that is being inserted. Deserialize it. */
+    UnpackedRecord *pUnpack = p->pNewUnpacked;
+    if( !pUnpack ){
+      Mem *pData = &p->v->aMem[p->iNewReg];
+      rc = ExpandBlob(pData);
+      if( rc!=SQLITE_OK ) goto preupdate_new_out;
+      pUnpack = vdbeUnpackRecord(&p->keyinfo, pData->n, pData->z);
+      if( !pUnpack ){
+        rc = SQLITE_NOMEM;
+        goto preupdate_new_out;
+      }
+      p->pNewUnpacked = pUnpack;
+    }
+    pMem = &pUnpack->aMem[iStore];
+    if( iIdx==p->pTab->iPKey ){
+      sqlite3VdbeMemSetInt64(pMem, p->iKey2);
+    }else if( iStore>=pUnpack->nField ){
+      pMem = (sqlite3_value *)columnNullValue();
+    }
+  }else{
+    /* For an UPDATE, memory cell (p->iNewReg+1+iStore) contains the required
+    ** value. Make a copy of the cell contents and return a pointer to it.
+    ** It is not safe to return a pointer to the memory cell itself as the
+    ** caller may modify the value text encoding.
+    */
+    assert( p->op==SQLITE_UPDATE );
+    if( !p->aNew ){
+      p->aNew = (Mem *)sqlite3DbMallocZero(db, sizeof(Mem) * p->pCsr->nField);
+      if( !p->aNew ){
+        rc = SQLITE_NOMEM;
+        goto preupdate_new_out;
+      }
+    }
+    assert( iStore>=0 && iStore<p->pCsr->nField );
+    pMem = &p->aNew[iStore];
+    if( pMem->flags==0 ){
+      if( iIdx==p->pTab->iPKey ){
+        sqlite3VdbeMemSetInt64(pMem, p->iKey2);
+      }else{
+        rc = sqlite3VdbeMemCopy(pMem, &p->v->aMem[p->iNewReg+1+iStore]);
+        if( rc!=SQLITE_OK ) goto preupdate_new_out;
+      }
+    }
+  }
+  *ppValue = pMem;
+
+ preupdate_new_out:
+  sqlite3Error(db, rc);
+  return sqlite3ApiExit(db, rc);
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+/*
+** Return status data for a single loop within query pStmt.
+*/
+SQLITE_API int sqlite3_stmt_scanstatus_v2(
+  sqlite3_stmt *pStmt,            /* Prepared statement being queried */
+  int iScan,                      /* Index of loop to report on */
+  int iScanStatusOp,              /* Which metric to return */
+  int flags,
+  void *pOut                      /* OUT: Write the answer here */
+){
+  Vdbe *p = (Vdbe*)pStmt;
+  VdbeOp *aOp;
+  int nOp;
+  ScanStatus *pScan = 0;
+  int idx;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( p==0 || pOut==0
+      || iScanStatusOp<SQLITE_SCANSTAT_NLOOP
+      || iScanStatusOp>SQLITE_SCANSTAT_NCYCLE ){
+    return 1;
+  }
+#endif
+  aOp = p->aOp;
+  nOp = p->nOp;
+  if( p->pFrame ){
+    VdbeFrame *pFrame;
+    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
+    aOp = pFrame->aOp;
+    nOp = pFrame->nOp;
+  }
+
+  if( iScan<0 ){
+    int ii;
+    if( iScanStatusOp==SQLITE_SCANSTAT_NCYCLE ){
+      i64 res = 0;
+      for(ii=0; ii<nOp; ii++){
+        res += aOp[ii].nCycle;
+      }
+      *(i64*)pOut = res;
+      return 0;
+    }
+    return 1;
+  }
+  if( flags & SQLITE_SCANSTAT_COMPLEX ){
+    idx = iScan;
+  }else{
+    /* If the COMPLEX flag is clear, then this function must ignore any
+    ** ScanStatus structures with ScanStatus.addrLoop set to 0. */
+    for(idx=0; idx<p->nScan; idx++){
+      pScan = &p->aScan[idx];
+      if( pScan->zName ){
+        iScan--;
+        if( iScan<0 ) break;
+      }
+    }
+  }
+  if( idx>=p->nScan ) return 1;
+  assert( pScan==0 || pScan==&p->aScan[idx] );
+  pScan = &p->aScan[idx];
+
+  switch( iScanStatusOp ){
+    case SQLITE_SCANSTAT_NLOOP: {
+      if( pScan->addrLoop>0 ){
+        *(sqlite3_int64*)pOut = aOp[pScan->addrLoop].nExec;
+      }else{
+        *(sqlite3_int64*)pOut = -1;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_NVISIT: {
+      if( pScan->addrVisit>0 ){
+        *(sqlite3_int64*)pOut = aOp[pScan->addrVisit].nExec;
+      }else{
+        *(sqlite3_int64*)pOut = -1;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_EST: {
+      double r = 1.0;
+      LogEst x = pScan->nEst;
+      while( x<100 ){
+        x += 10;
+        r *= 0.5;
+      }
+      *(double*)pOut = r*sqlite3LogEstToInt(x);
+      break;
+    }
+    case SQLITE_SCANSTAT_NAME: {
+      *(const char**)pOut = pScan->zName;
+      break;
+    }
+    case SQLITE_SCANSTAT_EXPLAIN: {
+      if( pScan->addrExplain ){
+        *(const char**)pOut = aOp[ pScan->addrExplain ].p4.z;
+      }else{
+        *(const char**)pOut = 0;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_SELECTID: {
+      if( pScan->addrExplain ){
+        *(int*)pOut = aOp[ pScan->addrExplain ].p1;
+      }else{
+        *(int*)pOut = -1;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_PARENTID: {
+      if( pScan->addrExplain ){
+        *(int*)pOut = aOp[ pScan->addrExplain ].p2;
+      }else{
+        *(int*)pOut = -1;
+      }
+      break;
+    }
+    case SQLITE_SCANSTAT_NCYCLE: {
+      i64 res = 0;
+      if( pScan->aAddrRange[0]==0 ){
+        res = -1;
+      }else{
+        int ii;
+        for(ii=0; ii<ArraySize(pScan->aAddrRange); ii+=2){
+          int iIns = pScan->aAddrRange[ii];
+          int iEnd = pScan->aAddrRange[ii+1];
+          if( iIns==0 ) break;
+          if( iIns>0 ){
+            while( iIns<=iEnd ){
+              res += aOp[iIns].nCycle;
+              iIns++;
+            }
+          }else{
+            int iOp;
+            for(iOp=0; iOp<nOp; iOp++){
+              Op *pOp = &aOp[iOp];
+              if( pOp->p1!=iEnd ) continue;
+              if( (sqlite3OpcodeProperty[pOp->opcode] & OPFLG_NCYCLE)==0 ){
+                continue;
+              }
+              res += aOp[iOp].nCycle;
+            }
+          }
+        }
+      }
+      *(i64*)pOut = res;
+      break;
+    }
+    default: {
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Return status data for a single loop within query pStmt.
+*/
+SQLITE_API int sqlite3_stmt_scanstatus(
+  sqlite3_stmt *pStmt,            /* Prepared statement being queried */
+  int iScan,                      /* Index of loop to report on */
+  int iScanStatusOp,              /* Which metric to return */
+  void *pOut                      /* OUT: Write the answer here */
+){
+  return sqlite3_stmt_scanstatus_v2(pStmt, iScan, iScanStatusOp, 0, pOut);
+}
+
+/*
+** Zero all counters associated with the sqlite3_stmt_scanstatus() data.
+*/
+SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt *pStmt){
+  Vdbe *p = (Vdbe*)pStmt;
+  int ii;
+  for(ii=0; p!=0 && ii<p->nOp; ii++){
+    Op *pOp = &p->aOp[ii];
+    pOp->nExec = 0;
+    pOp->nCycle = 0;
+  }
+}
+#endif /* SQLITE_ENABLE_STMT_SCANSTATUS */
+
+/************** End of vdbeapi.c *********************************************/
+/************** Begin file vdbetrace.c ***************************************/
+/*
+** 2009 November 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code used to insert the values of host parameters
+** (aka "wildcards") into the SQL text output by sqlite3_trace().
+**
+** The Vdbe parse-tree explainer is also found here.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+#ifndef SQLITE_OMIT_TRACE
+
+/*
+** zSql is a zero-terminated string of UTF-8 SQL text.  Return the number of
+** bytes in this text up to but excluding the first character in
+** a host parameter.  If the text contains no host parameters, return
+** the total number of bytes in the text.
+*/
+static int findNextHostParameter(const char *zSql, int *pnToken){
+  int tokenType;
+  int nTotal = 0;
+  int n;
+
+  *pnToken = 0;
+  while( zSql[0] ){
+    n = sqlite3GetToken((u8*)zSql, &tokenType);
+    assert( n>0 && tokenType!=TK_ILLEGAL );
+    if( tokenType==TK_VARIABLE ){
+      *pnToken = n;
+      break;
+    }
+    nTotal += n;
+    zSql += n;
+  }
+  return nTotal;
+}
+
+/*
+** This function returns a pointer to a nul-terminated string in memory
+** obtained from sqlite3DbMalloc(). If sqlite3.nVdbeExec is 1, then the
+** string contains a copy of zRawSql but with host parameters expanded to
+** their current bindings. Or, if sqlite3.nVdbeExec is greater than 1,
+** then the returned string holds a copy of zRawSql with "-- " prepended
+** to each line of text.
+**
+** If the SQLITE_TRACE_SIZE_LIMIT macro is defined to an integer, then
+** then long strings and blobs are truncated to that many bytes.  This
+** can be used to prevent unreasonably large trace strings when dealing
+** with large (multi-megabyte) strings and blobs.
+**
+** The calling function is responsible for making sure the memory returned
+** is eventually freed.
+**
+** ALGORITHM:  Scan the input string looking for host parameters in any of
+** these forms:  ?, ?N, $A, @A, :A.  Take care to avoid text within
+** string literals, quoted identifier names, and comments.  For text forms,
+** the host parameter index is found by scanning the prepared
+** statement for the corresponding OP_Variable opcode.  Once the host
+** parameter index is known, locate the value in p->aVar[].  Then render
+** the value as a literal in place of the host parameter name.
+*/
+SQLITE_PRIVATE char *sqlite3VdbeExpandSql(
+  Vdbe *p,                 /* The prepared statement being evaluated */
+  const char *zRawSql      /* Raw text of the SQL statement */
+){
+  sqlite3 *db;             /* The database connection */
+  int idx = 0;             /* Index of a host parameter */
+  int nextIndex = 1;       /* Index of next ? host parameter */
+  int n;                   /* Length of a token prefix */
+  int nToken;              /* Length of the parameter token */
+  int i;                   /* Loop counter */
+  Mem *pVar;               /* Value of a host parameter */
+  StrAccum out;            /* Accumulate the output here */
+#ifndef SQLITE_OMIT_UTF16
+  Mem utf8;                /* Used to convert UTF16 into UTF8 for display */
+#endif
+
+  db = p->db;
+  sqlite3StrAccumInit(&out, 0, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
+  if( db->nVdbeExec>1 ){
+    while( *zRawSql ){
+      const char *zStart = zRawSql;
+      while( *(zRawSql++)!='\n' && *zRawSql );
+      sqlite3_str_append(&out, "-- ", 3);
+      assert( (zRawSql - zStart) > 0 );
+      sqlite3_str_append(&out, zStart, (int)(zRawSql-zStart));
+    }
+  }else if( p->nVar==0 ){
+    sqlite3_str_append(&out, zRawSql, sqlite3Strlen30(zRawSql));
+  }else{
+    while( zRawSql[0] ){
+      n = findNextHostParameter(zRawSql, &nToken);
+      assert( n>0 );
+      sqlite3_str_append(&out, zRawSql, n);
+      zRawSql += n;
+      assert( zRawSql[0] || nToken==0 );
+      if( nToken==0 ) break;
+      if( zRawSql[0]=='?' ){
+        if( nToken>1 ){
+          assert( sqlite3Isdigit(zRawSql[1]) );
+          sqlite3GetInt32(&zRawSql[1], &idx);
+        }else{
+          idx = nextIndex;
+        }
+      }else{
+        assert( zRawSql[0]==':' || zRawSql[0]=='$' ||
+                zRawSql[0]=='@' || zRawSql[0]=='#' );
+        testcase( zRawSql[0]==':' );
+        testcase( zRawSql[0]=='$' );
+        testcase( zRawSql[0]=='@' );
+        testcase( zRawSql[0]=='#' );
+        idx = sqlite3VdbeParameterIndex(p, zRawSql, nToken);
+        assert( idx>0 );
+      }
+      zRawSql += nToken;
+      nextIndex = MAX(idx + 1, nextIndex);
+      assert( idx>0 && idx<=p->nVar );
+      pVar = &p->aVar[idx-1];
+      if( pVar->flags & MEM_Null ){
+        sqlite3_str_append(&out, "NULL", 4);
+      }else if( pVar->flags & (MEM_Int|MEM_IntReal) ){
+        sqlite3_str_appendf(&out, "%lld", pVar->u.i);
+      }else if( pVar->flags & MEM_Real ){
+        sqlite3_str_appendf(&out, "%!.15g", pVar->u.r);
+      }else if( pVar->flags & MEM_Str ){
+        int nOut;  /* Number of bytes of the string text to include in output */
+#ifndef SQLITE_OMIT_UTF16
+        u8 enc = ENC(db);
+        if( enc!=SQLITE_UTF8 ){
+          memset(&utf8, 0, sizeof(utf8));
+          utf8.db = db;
+          sqlite3VdbeMemSetStr(&utf8, pVar->z, pVar->n, enc, SQLITE_STATIC);
+          if( SQLITE_NOMEM==sqlite3VdbeChangeEncoding(&utf8, SQLITE_UTF8) ){
+            out.accError = SQLITE_NOMEM;
+            out.nAlloc = 0;
+          }
+          pVar = &utf8;
+        }
+#endif
+        nOut = pVar->n;
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut>SQLITE_TRACE_SIZE_LIMIT ){
+          nOut = SQLITE_TRACE_SIZE_LIMIT;
+          while( nOut<pVar->n && (pVar->z[nOut]&0xc0)==0x80 ){ nOut++; }
+        }
+#endif
+        sqlite3_str_appendf(&out, "'%.*q'", nOut, pVar->z);
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut<pVar->n ){
+          sqlite3_str_appendf(&out, "/*+%d bytes*/", pVar->n-nOut);
+        }
+#endif
+#ifndef SQLITE_OMIT_UTF16
+        if( enc!=SQLITE_UTF8 ) sqlite3VdbeMemRelease(&utf8);
+#endif
+      }else if( pVar->flags & MEM_Zero ){
+        sqlite3_str_appendf(&out, "zeroblob(%d)", pVar->u.nZero);
+      }else{
+        int nOut;  /* Number of bytes of the blob to include in output */
+        assert( pVar->flags & MEM_Blob );
+        sqlite3_str_append(&out, "x'", 2);
+        nOut = pVar->n;
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut>SQLITE_TRACE_SIZE_LIMIT ) nOut = SQLITE_TRACE_SIZE_LIMIT;
+#endif
+        for(i=0; i<nOut; i++){
+          sqlite3_str_appendf(&out, "%02x", pVar->z[i]&0xff);
+        }
+        sqlite3_str_append(&out, "'", 1);
+#ifdef SQLITE_TRACE_SIZE_LIMIT
+        if( nOut<pVar->n ){
+          sqlite3_str_appendf(&out, "/*+%d bytes*/", pVar->n-nOut);
+        }
+#endif
+      }
+    }
+  }
+  if( out.accError ) sqlite3_str_reset(&out);
+  return sqlite3StrAccumFinish(&out);
+}
+
+#endif /* #ifndef SQLITE_OMIT_TRACE */
+
+/************** End of vdbetrace.c *******************************************/
+/************** Begin file vdbe.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** The code in this file implements the function that runs the
+** bytecode of a prepared statement.
+**
+** Various scripts scan this source file in order to generate HTML
+** documentation, headers files, or other derived files.  The formatting
+** of the code in this file is, therefore, important.  See other comments
+** in this file for details.  If in doubt, do not deviate from existing
+** commenting and indentation practices when changing or adding code.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+/*
+** High-resolution hardware timer used for debugging and testing only.
+*/
+#if defined(VDBE_PROFILE)  \
+ || defined(SQLITE_PERFORMANCE_TRACE) \
+ || defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+/************** Include hwtime.h in the middle of vdbe.c *********************/
+/************** Begin file hwtime.h ******************************************/
+/*
+** 2008 May 27
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains inline asm code for retrieving "high-performance"
+** counters for x86 and x86_64 class CPUs.
+*/
+#ifndef SQLITE_HWTIME_H
+#define SQLITE_HWTIME_H
+
+/*
+** The following routine only works on Pentium-class (or newer) processors.
+** It uses the RDTSC opcode to read the cycle count value out of the
+** processor and returns that value.  This can be used for high-res
+** profiling.
+*/
+#if !defined(__STRICT_ANSI__) && \
+    (defined(__GNUC__) || defined(_MSC_VER)) && \
+    (defined(i386) || defined(__i386__) || defined(_M_IX86))
+
+  #if defined(__GNUC__)
+
+  __inline__ sqlite_uint64 sqlite3Hwtime(void){
+     unsigned int lo, hi;
+     __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
+     return (sqlite_uint64)hi << 32 | lo;
+  }
+
+  #elif defined(_MSC_VER)
+
+  __declspec(naked) __inline sqlite_uint64 __cdecl sqlite3Hwtime(void){
+     __asm {
+        rdtsc
+        ret       ; return value at EDX:EAX
+     }
+  }
+
+  #endif
+
+#elif !defined(__STRICT_ANSI__) && (defined(__GNUC__) && defined(__x86_64__))
+
+  __inline__ sqlite_uint64 sqlite3Hwtime(void){
+     unsigned int lo, hi;
+     __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
+     return (sqlite_uint64)hi << 32 | lo;
+  }
+
+#elif !defined(__STRICT_ANSI__) && (defined(__GNUC__) && defined(__ppc__))
+
+  __inline__ sqlite_uint64 sqlite3Hwtime(void){
+      unsigned long long retval;
+      unsigned long junk;
+      __asm__ __volatile__ ("\n\
+          1:      mftbu   %1\n\
+                  mftb    %L0\n\
+                  mftbu   %0\n\
+                  cmpw    %0,%1\n\
+                  bne     1b"
+                  : "=r" (retval), "=r" (junk));
+      return retval;
+  }
+
+#else
+
+  /*
+  ** asm() is needed for hardware timing support.  Without asm(),
+  ** disable the sqlite3Hwtime() routine.
+  **
+  ** sqlite3Hwtime() is only used for some obscure debugging
+  ** and analysis configurations, not in any deliverable, so this
+  ** should not be a great loss.
+  */
+SQLITE_PRIVATE   sqlite_uint64 sqlite3Hwtime(void){ return ((sqlite_uint64)0); }
+
+#endif
+
+#endif /* !defined(SQLITE_HWTIME_H) */
+
+/************** End of hwtime.h **********************************************/
+/************** Continuing where we left off in vdbe.c ***********************/
+#endif
+
+/*
+** Invoke this macro on memory cells just prior to changing the
+** value of the cell.  This macro verifies that shallow copies are
+** not misused.  A shallow copy of a string or blob just copies a
+** pointer to the string or blob, not the content.  If the original
+** is changed while the copy is still in use, the string or blob might
+** be changed out from under the copy.  This macro verifies that nothing
+** like that ever happens.
+*/
+#ifdef SQLITE_DEBUG
+# define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
+#else
+# define memAboutToChange(P,M)
+#endif
+
+/*
+** The following global variable is incremented every time a cursor
+** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
+** procedures use this information to make sure that indices are
+** working correctly.  This variable has no function other than to
+** help verify the correct operation of the library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_search_count = 0;
+#endif
+
+/*
+** When this global variable is positive, it gets decremented once before
+** each instruction in the VDBE.  When it reaches zero, the u1.isInterrupted
+** field of the sqlite3 structure is set in order to simulate an interrupt.
+**
+** This facility is used for testing purposes only.  It does not function
+** in an ordinary build.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_interrupt_count = 0;
+#endif
+
+/*
+** The next global variable is incremented each type the OP_Sort opcode
+** is executed.  The test procedures use this information to make sure that
+** sorting is occurring or not occurring at appropriate times.   This variable
+** has no function other than to help verify the correct operation of the
+** library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_sort_count = 0;
+#endif
+
+/*
+** The next global variable records the size of the largest MEM_Blob
+** or MEM_Str that has been used by a VDBE opcode.  The test procedures
+** use this information to make sure that the zero-blob functionality
+** is working correctly.   This variable has no function other than to
+** help verify the correct operation of the library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_max_blobsize = 0;
+static void updateMaxBlobsize(Mem *p){
+  if( (p->flags & (MEM_Str|MEM_Blob))!=0 && p->n>sqlite3_max_blobsize ){
+    sqlite3_max_blobsize = p->n;
+  }
+}
+#endif
+
+/*
+** This macro evaluates to true if either the update hook or the preupdate
+** hook are enabled for database connect DB.
+*/
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+# define HAS_UPDATE_HOOK(DB) ((DB)->xPreUpdateCallback||(DB)->xUpdateCallback)
+#else
+# define HAS_UPDATE_HOOK(DB) ((DB)->xUpdateCallback)
+#endif
+
+/*
+** The next global variable is incremented each time the OP_Found opcode
+** is executed. This is used to test whether or not the foreign key
+** operation implemented using OP_FkIsZero is working. This variable
+** has no function other than to help verify the correct operation of the
+** library.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_found_count = 0;
+#endif
+
+/*
+** Test a register to see if it exceeds the current maximum blob size.
+** If it does, record the new maximum blob size.
+*/
+#if defined(SQLITE_TEST) && !defined(SQLITE_UNTESTABLE)
+# define UPDATE_MAX_BLOBSIZE(P)  updateMaxBlobsize(P)
+#else
+# define UPDATE_MAX_BLOBSIZE(P)
+#endif
+
+#ifdef SQLITE_DEBUG
+/* This routine provides a convenient place to set a breakpoint during
+** tracing with PRAGMA vdbe_trace=on.  The breakpoint fires right after
+** each opcode is printed.  Variables "pc" (program counter) and pOp are
+** available to add conditionals to the breakpoint.  GDB example:
+**
+**         break test_trace_breakpoint if pc=22
+**
+** Other useful labels for breakpoints include:
+**   test_addop_breakpoint(pc,pOp)
+**   sqlite3CorruptError(lineno)
+**   sqlite3MisuseError(lineno)
+**   sqlite3CantopenError(lineno)
+*/
+static void test_trace_breakpoint(int pc, Op *pOp, Vdbe *v){
+  static u64 n = 0;
+  (void)pc;
+  (void)pOp;
+  (void)v;
+  n++;
+  if( n==LARGEST_UINT64 ) abort(); /* So that n is used, preventing a warning */
+}
+#endif
+
+/*
+** Invoke the VDBE coverage callback, if that callback is defined.  This
+** feature is used for test suite validation only and does not appear an
+** production builds.
+**
+** M is the type of branch.  I is the direction taken for this instance of
+** the branch.
+**
+**   M: 2 - two-way branch (I=0: fall-thru   1: jump                )
+**      3 - two-way + NULL (I=0: fall-thru   1: jump      2: NULL   )
+**      4 - OP_Jump        (I=0: jump p1     1: jump p2   2: jump p3)
+**
+** In other words, if M is 2, then I is either 0 (for fall-through) or
+** 1 (for when the branch is taken).  If M is 3, the I is 0 for an
+** ordinary fall-through, I is 1 if the branch was taken, and I is 2
+** if the result of comparison is NULL.  For M=3, I=2 the jump may or
+** may not be taken, depending on the SQLITE_JUMPIFNULL flags in p5.
+** When M is 4, that means that an OP_Jump is being run.  I is 0, 1, or 2
+** depending on if the operands are less than, equal, or greater than.
+**
+** iSrcLine is the source code line (from the __LINE__ macro) that
+** generated the VDBE instruction combined with flag bits.  The source
+** code line number is in the lower 24 bits of iSrcLine and the upper
+** 8 bytes are flags.  The lower three bits of the flags indicate
+** values for I that should never occur.  For example, if the branch is
+** always taken, the flags should be 0x05 since the fall-through and
+** alternate branch are never taken.  If a branch is never taken then
+** flags should be 0x06 since only the fall-through approach is allowed.
+**
+** Bit 0x08 of the flags indicates an OP_Jump opcode that is only
+** interested in equal or not-equal.  In other words, I==0 and I==2
+** should be treated as equivalent
+**
+** Since only a line number is retained, not the filename, this macro
+** only works for amalgamation builds.  But that is ok, since these macros
+** should be no-ops except for special builds used to measure test coverage.
+*/
+#if !defined(SQLITE_VDBE_COVERAGE)
+# define VdbeBranchTaken(I,M)
+#else
+# define VdbeBranchTaken(I,M) vdbeTakeBranch(pOp->iSrcLine,I,M)
+  static void vdbeTakeBranch(u32 iSrcLine, u8 I, u8 M){
+    u8 mNever;
+    assert( I<=2 );  /* 0: fall through,  1: taken,  2: alternate taken */
+    assert( M<=4 );  /* 2: two-way branch, 3: three-way branch, 4: OP_Jump */
+    assert( I<M );   /* I can only be 2 if M is 3 or 4 */
+    /* Transform I from a integer [0,1,2] into a bitmask of [1,2,4] */
+    I = 1<<I;
+    /* The upper 8 bits of iSrcLine are flags.  The lower three bits of
+    ** the flags indicate directions that the branch can never go.  If
+    ** a branch really does go in one of those directions, assert right
+    ** away. */
+    mNever = iSrcLine >> 24;
+    assert( (I & mNever)==0 );
+    if( sqlite3GlobalConfig.xVdbeBranch==0 ) return;  /*NO_TEST*/
+    /* Invoke the branch coverage callback with three arguments:
+    **    iSrcLine - the line number of the VdbeCoverage() macro, with
+    **               flags removed.
+    **    I        - Mask of bits 0x07 indicating which cases are are
+    **               fulfilled by this instance of the jump.  0x01 means
+    **               fall-thru, 0x02 means taken, 0x04 means NULL.  Any
+    **               impossible cases (ex: if the comparison is never NULL)
+    **               are filled in automatically so that the coverage
+    **               measurement logic does not flag those impossible cases
+    **               as missed coverage.
+    **    M        - Type of jump.  Same as M argument above
+    */
+    I |= mNever;
+    if( M==2 ) I |= 0x04;
+    if( M==4 ){
+      I |= 0x08;
+      if( (mNever&0x08)!=0 && (I&0x05)!=0) I |= 0x05; /*NO_TEST*/
+    }
+    sqlite3GlobalConfig.xVdbeBranch(sqlite3GlobalConfig.pVdbeBranchArg,
+                                    iSrcLine&0xffffff, I, M);
+  }
+#endif
+
+/*
+** An ephemeral string value (signified by the MEM_Ephem flag) contains
+** a pointer to a dynamically allocated string where some other entity
+** is responsible for deallocating that string.  Because the register
+** does not control the string, it might be deleted without the register
+** knowing it.
+**
+** This routine converts an ephemeral string into a dynamically allocated
+** string that the register itself controls.  In other words, it
+** converts an MEM_Ephem string into a string with P.z==P.zMalloc.
+*/
+#define Deephemeralize(P) \
+   if( ((P)->flags&MEM_Ephem)!=0 \
+       && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}
+
+/* Return true if the cursor was opened using the OP_OpenSorter opcode. */
+#define isSorter(x) ((x)->eCurType==CURTYPE_SORTER)
+
+/*
+** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
+** if we run out of memory.
+*/
+static VdbeCursor *allocateCursor(
+  Vdbe *p,              /* The virtual machine */
+  int iCur,             /* Index of the new VdbeCursor */
+  int nField,           /* Number of fields in the table or index */
+  u8 eCurType           /* Type of the new cursor */
+){
+  /* Find the memory cell that will be used to store the blob of memory
+  ** required for this VdbeCursor structure. It is convenient to use a
+  ** vdbe memory cell to manage the memory allocation required for a
+  ** VdbeCursor structure for the following reasons:
+  **
+  **   * Sometimes cursor numbers are used for a couple of different
+  **     purposes in a vdbe program. The different uses might require
+  **     different sized allocations. Memory cells provide growable
+  **     allocations.
+  **
+  **   * When using ENABLE_MEMORY_MANAGEMENT, memory cell buffers can
+  **     be freed lazily via the sqlite3_release_memory() API. This
+  **     minimizes the number of malloc calls made by the system.
+  **
+  ** The memory cell for cursor 0 is aMem[0]. The rest are allocated from
+  ** the top of the register space.  Cursor 1 is at Mem[p->nMem-1].
+  ** Cursor 2 is at Mem[p->nMem-2]. And so forth.
+  */
+  Mem *pMem = iCur>0 ? &p->aMem[p->nMem-iCur] : p->aMem;
+
+  int nByte;
+  VdbeCursor *pCx = 0;
+  nByte =
+      ROUND8P(sizeof(VdbeCursor)) + 2*sizeof(u32)*nField +
+      (eCurType==CURTYPE_BTREE?sqlite3BtreeCursorSize():0);
+
+  assert( iCur>=0 && iCur<p->nCursor );
+  if( p->apCsr[iCur] ){ /*OPTIMIZATION-IF-FALSE*/
+    sqlite3VdbeFreeCursorNN(p, p->apCsr[iCur]);
+    p->apCsr[iCur] = 0;
+  }
+
+  /* There used to be a call to sqlite3VdbeMemClearAndResize() to make sure
+  ** the pMem used to hold space for the cursor has enough storage available
+  ** in pMem->zMalloc.  But for the special case of the aMem[] entries used
+  ** to hold cursors, it is faster to in-line the logic. */
+  assert( pMem->flags==MEM_Undefined );
+  assert( (pMem->flags & MEM_Dyn)==0 );
+  assert( pMem->szMalloc==0 || pMem->z==pMem->zMalloc );
+  if( pMem->szMalloc<nByte ){
+    if( pMem->szMalloc>0 ){
+      sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
+    }
+    pMem->z = pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, nByte);
+    if( pMem->zMalloc==0 ){
+      pMem->szMalloc = 0;
+      return 0;
+    }
+    pMem->szMalloc = nByte;
+  }
+
+  p->apCsr[iCur] = pCx = (VdbeCursor*)pMem->zMalloc;
+  memset(pCx, 0, offsetof(VdbeCursor,pAltCursor));
+  pCx->eCurType = eCurType;
+  pCx->nField = nField;
+  pCx->aOffset = &pCx->aType[nField];
+  if( eCurType==CURTYPE_BTREE ){
+    pCx->uc.pCursor = (BtCursor*)
+        &pMem->z[ROUND8P(sizeof(VdbeCursor))+2*sizeof(u32)*nField];
+    sqlite3BtreeCursorZero(pCx->uc.pCursor);
+  }
+  return pCx;
+}
+
+/*
+** The string in pRec is known to look like an integer and to have a
+** floating point value of rValue.  Return true and set *piValue to the
+** integer value if the string is in range to be an integer.  Otherwise,
+** return false.
+*/
+static int alsoAnInt(Mem *pRec, double rValue, i64 *piValue){
+  i64 iValue;
+  iValue = sqlite3RealToI64(rValue);
+  if( sqlite3RealSameAsInt(rValue,iValue) ){
+    *piValue = iValue;
+    return 1;
+  }
+  return 0==sqlite3Atoi64(pRec->z, piValue, pRec->n, pRec->enc);
+}
+
+/*
+** Try to convert a value into a numeric representation if we can
+** do so without loss of information.  In other words, if the string
+** looks like a number, convert it into a number.  If it does not
+** look like a number, leave it alone.
+**
+** If the bTryForInt flag is true, then extra effort is made to give
+** an integer representation.  Strings that look like floating point
+** values but which have no fractional component (example: '48.00')
+** will have a MEM_Int representation when bTryForInt is true.
+**
+** If bTryForInt is false, then if the input string contains a decimal
+** point or exponential notation, the result is only MEM_Real, even
+** if there is an exact integer representation of the quantity.
+*/
+static void applyNumericAffinity(Mem *pRec, int bTryForInt){
+  double rValue;
+  u8 enc = pRec->enc;
+  int rc;
+  assert( (pRec->flags & (MEM_Str|MEM_Int|MEM_Real|MEM_IntReal))==MEM_Str );
+  rc = sqlite3AtoF(pRec->z, &rValue, pRec->n, enc);
+  if( rc<=0 ) return;
+  if( rc==1 && alsoAnInt(pRec, rValue, &pRec->u.i) ){
+    pRec->flags |= MEM_Int;
+  }else{
+    pRec->u.r = rValue;
+    pRec->flags |= MEM_Real;
+    if( bTryForInt ) sqlite3VdbeIntegerAffinity(pRec);
+  }
+  /* TEXT->NUMERIC is many->one.  Hence, it is important to invalidate the
+  ** string representation after computing a numeric equivalent, because the
+  ** string representation might not be the canonical representation for the
+  ** numeric value.  Ticket [343634942dd54ab57b7024] 2018-01-31. */
+  pRec->flags &= ~MEM_Str;
+}
+
+/*
+** Processing is determine by the affinity parameter:
+**
+** SQLITE_AFF_INTEGER:
+** SQLITE_AFF_REAL:
+** SQLITE_AFF_NUMERIC:
+**    Try to convert pRec to an integer representation or a
+**    floating-point representation if an integer representation
+**    is not possible.  Note that the integer representation is
+**    always preferred, even if the affinity is REAL, because
+**    an integer representation is more space efficient on disk.
+**
+** SQLITE_AFF_FLEXNUM:
+**    If the value is text, then try to convert it into a number of
+**    some kind (integer or real) but do not make any other changes.
+**
+** SQLITE_AFF_TEXT:
+**    Convert pRec to a text representation.
+**
+** SQLITE_AFF_BLOB:
+** SQLITE_AFF_NONE:
+**    No-op.  pRec is unchanged.
+*/
+static void applyAffinity(
+  Mem *pRec,          /* The value to apply affinity to */
+  char affinity,      /* The affinity to be applied */
+  u8 enc              /* Use this text encoding */
+){
+  if( affinity>=SQLITE_AFF_NUMERIC ){
+    assert( affinity==SQLITE_AFF_INTEGER || affinity==SQLITE_AFF_REAL
+             || affinity==SQLITE_AFF_NUMERIC || affinity==SQLITE_AFF_FLEXNUM );
+    if( (pRec->flags & MEM_Int)==0 ){ /*OPTIMIZATION-IF-FALSE*/
+      if( (pRec->flags & (MEM_Real|MEM_IntReal))==0 ){
+        if( pRec->flags & MEM_Str ) applyNumericAffinity(pRec,1);
+      }else if( affinity<=SQLITE_AFF_REAL ){
+        sqlite3VdbeIntegerAffinity(pRec);
+      }
+    }
+  }else if( affinity==SQLITE_AFF_TEXT ){
+    /* Only attempt the conversion to TEXT if there is an integer or real
+    ** representation (blob and NULL do not get converted) but no string
+    ** representation.  It would be harmless to repeat the conversion if
+    ** there is already a string rep, but it is pointless to waste those
+    ** CPU cycles. */
+    if( 0==(pRec->flags&MEM_Str) ){ /*OPTIMIZATION-IF-FALSE*/
+      if( (pRec->flags&(MEM_Real|MEM_Int|MEM_IntReal)) ){
+        testcase( pRec->flags & MEM_Int );
+        testcase( pRec->flags & MEM_Real );
+        testcase( pRec->flags & MEM_IntReal );
+        sqlite3VdbeMemStringify(pRec, enc, 1);
+      }
+    }
+    pRec->flags &= ~(MEM_Real|MEM_Int|MEM_IntReal);
+  }
+}
+
+/*
+** Try to convert the type of a function argument or a result column
+** into a numeric representation.  Use either INTEGER or REAL whichever
+** is appropriate.  But only do the conversion if it is possible without
+** loss of information and return the revised type of the argument.
+*/
+SQLITE_API int sqlite3_value_numeric_type(sqlite3_value *pVal){
+  int eType = sqlite3_value_type(pVal);
+  if( eType==SQLITE_TEXT ){
+    Mem *pMem = (Mem*)pVal;
+    applyNumericAffinity(pMem, 0);
+    eType = sqlite3_value_type(pVal);
+  }
+  return eType;
+}
+
+/*
+** Exported version of applyAffinity(). This one works on sqlite3_value*,
+** not the internal Mem* type.
+*/
+SQLITE_PRIVATE void sqlite3ValueApplyAffinity(
+  sqlite3_value *pVal,
+  u8 affinity,
+  u8 enc
+){
+  applyAffinity((Mem *)pVal, affinity, enc);
+}
+
+/*
+** pMem currently only holds a string type (or maybe a BLOB that we can
+** interpret as a string if we want to).  Compute its corresponding
+** numeric type, if has one.  Set the pMem->u.r and pMem->u.i fields
+** accordingly.
+*/
+static u16 SQLITE_NOINLINE computeNumericType(Mem *pMem){
+  int rc;
+  sqlite3_int64 ix;
+  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal))==0 );
+  assert( (pMem->flags & (MEM_Str|MEM_Blob))!=0 );
+  if( ExpandBlob(pMem) ){
+    pMem->u.i = 0;
+    return MEM_Int;
+  }
+  rc = sqlite3AtoF(pMem->z, &pMem->u.r, pMem->n, pMem->enc);
+  if( rc<=0 ){
+    if( rc==0 && sqlite3Atoi64(pMem->z, &ix, pMem->n, pMem->enc)<=1 ){
+      pMem->u.i = ix;
+      return MEM_Int;
+    }else{
+      return MEM_Real;
+    }
+  }else if( rc==1 && sqlite3Atoi64(pMem->z, &ix, pMem->n, pMem->enc)==0 ){
+    pMem->u.i = ix;
+    return MEM_Int;
+  }
+  return MEM_Real;
+}
+
+/*
+** Return the numeric type for pMem, either MEM_Int or MEM_Real or both or
+** none.
+**
+** Unlike applyNumericAffinity(), this routine does not modify pMem->flags.
+** But it does set pMem->u.r and pMem->u.i appropriately.
+*/
+static u16 numericType(Mem *pMem){
+  assert( (pMem->flags & MEM_Null)==0
+       || pMem->db==0 || pMem->db->mallocFailed );
+  if( pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null) ){
+    testcase( pMem->flags & MEM_Int );
+    testcase( pMem->flags & MEM_Real );
+    testcase( pMem->flags & MEM_IntReal );
+    return pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null);
+  }
+  assert( pMem->flags & (MEM_Str|MEM_Blob) );
+  testcase( pMem->flags & MEM_Str );
+  testcase( pMem->flags & MEM_Blob );
+  return computeNumericType(pMem);
+  return 0;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Write a nice string representation of the contents of cell pMem
+** into buffer zBuf, length nBuf.
+*/
+SQLITE_PRIVATE void sqlite3VdbeMemPrettyPrint(Mem *pMem, StrAccum *pStr){
+  int f = pMem->flags;
+  static const char *const encnames[] = {"(X)", "(8)", "(16LE)", "(16BE)"};
+  if( f&MEM_Blob ){
+    int i;
+    char c;
+    if( f & MEM_Dyn ){
+      c = 'z';
+      assert( (f & (MEM_Static|MEM_Ephem))==0 );
+    }else if( f & MEM_Static ){
+      c = 't';
+      assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
+    }else if( f & MEM_Ephem ){
+      c = 'e';
+      assert( (f & (MEM_Static|MEM_Dyn))==0 );
+    }else{
+      c = 's';
+    }
+    sqlite3_str_appendf(pStr, "%cx[", c);
+    for(i=0; i<25 && i<pMem->n; i++){
+      sqlite3_str_appendf(pStr, "%02X", ((int)pMem->z[i] & 0xFF));
+    }
+    sqlite3_str_appendf(pStr, "|");
+    for(i=0; i<25 && i<pMem->n; i++){
+      char z = pMem->z[i];
+      sqlite3_str_appendchar(pStr, 1, (z<32||z>126)?'.':z);
+    }
+    sqlite3_str_appendf(pStr,"]");
+    if( f & MEM_Zero ){
+      sqlite3_str_appendf(pStr, "+%dz",pMem->u.nZero);
+    }
+  }else if( f & MEM_Str ){
+    int j;
+    u8 c;
+    if( f & MEM_Dyn ){
+      c = 'z';
+      assert( (f & (MEM_Static|MEM_Ephem))==0 );
+    }else if( f & MEM_Static ){
+      c = 't';
+      assert( (f & (MEM_Dyn|MEM_Ephem))==0 );
+    }else if( f & MEM_Ephem ){
+      c = 'e';
+      assert( (f & (MEM_Static|MEM_Dyn))==0 );
+    }else{
+      c = 's';
+    }
+    sqlite3_str_appendf(pStr, " %c%d[", c, pMem->n);
+    for(j=0; j<25 && j<pMem->n; j++){
+      c = pMem->z[j];
+      sqlite3_str_appendchar(pStr, 1, (c>=0x20&&c<=0x7f) ? c : '.');
+    }
+    sqlite3_str_appendf(pStr, "]%s", encnames[pMem->enc]);
+    if( f & MEM_Term ){
+      sqlite3_str_appendf(pStr, "(0-term)");
+    }
+  }
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Print the value of a register for tracing purposes:
+*/
+static void memTracePrint(Mem *p){
+  if( p->flags & MEM_Undefined ){
+    printf(" undefined");
+  }else if( p->flags & MEM_Null ){
+    printf(p->flags & MEM_Zero ? " NULL-nochng" : " NULL");
+  }else if( (p->flags & (MEM_Int|MEM_Str))==(MEM_Int|MEM_Str) ){
+    printf(" si:%lld", p->u.i);
+  }else if( (p->flags & (MEM_IntReal))!=0 ){
+    printf(" ir:%lld", p->u.i);
+  }else if( p->flags & MEM_Int ){
+    printf(" i:%lld", p->u.i);
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  }else if( p->flags & MEM_Real ){
+    printf(" r:%.17g", p->u.r);
+#endif
+  }else if( sqlite3VdbeMemIsRowSet(p) ){
+    printf(" (rowset)");
+  }else{
+    StrAccum acc;
+    char zBuf[1000];
+    sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+    sqlite3VdbeMemPrettyPrint(p, &acc);
+    printf(" %s", sqlite3StrAccumFinish(&acc));
+  }
+  if( p->flags & MEM_Subtype ) printf(" subtype=0x%02x", p->eSubtype);
+}
+static void registerTrace(int iReg, Mem *p){
+  printf("R[%d] = ", iReg);
+  memTracePrint(p);
+  if( p->pScopyFrom ){
+    assert( p->pScopyFrom->bScopy );
+    printf(" <== R[%d]", (int)(p->pScopyFrom - &p[-iReg]));
+  }
+  printf("\n");
+  sqlite3VdbeCheckMemInvariants(p);
+}
+/**/ void sqlite3PrintMem(Mem *pMem){
+  memTracePrint(pMem);
+  printf("\n");
+  fflush(stdout);
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Show the values of all registers in the virtual machine.  Used for
+** interactive debugging.
+*/
+SQLITE_PRIVATE void sqlite3VdbeRegisterDump(Vdbe *v){
+  int i;
+  for(i=1; i<v->nMem; i++) registerTrace(i, v->aMem+i);
+}
+#endif /* SQLITE_DEBUG */
+
+
+#ifdef SQLITE_DEBUG
+#  define REGISTER_TRACE(R,M) if(db->flags&SQLITE_VdbeTrace)registerTrace(R,M)
+#else
+#  define REGISTER_TRACE(R,M)
+#endif
+
+#ifndef NDEBUG
+/*
+** This function is only called from within an assert() expression. It
+** checks that the sqlite3.nTransaction variable is correctly set to
+** the number of non-transaction savepoints currently in the
+** linked list starting at sqlite3.pSavepoint.
+**
+** Usage:
+**
+**     assert( checkSavepointCount(db) );
+*/
+static int checkSavepointCount(sqlite3 *db){
+  int n = 0;
+  Savepoint *p;
+  for(p=db->pSavepoint; p; p=p->pNext) n++;
+  assert( n==(db->nSavepoint + db->isTransactionSavepoint) );
+  return 1;
+}
+#endif
+
+/*
+** Return the register of pOp->p2 after first preparing it to be
+** overwritten with an integer value.
+*/
+static SQLITE_NOINLINE Mem *out2PrereleaseWithClear(Mem *pOut){
+  sqlite3VdbeMemSetNull(pOut);
+  pOut->flags = MEM_Int;
+  return pOut;
+}
+static Mem *out2Prerelease(Vdbe *p, VdbeOp *pOp){
+  Mem *pOut;
+  assert( pOp->p2>0 );
+  assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
+  pOut = &p->aMem[pOp->p2];
+  memAboutToChange(p, pOut);
+  if( VdbeMemDynamic(pOut) ){ /*OPTIMIZATION-IF-FALSE*/
+    return out2PrereleaseWithClear(pOut);
+  }else{
+    pOut->flags = MEM_Int;
+    return pOut;
+  }
+}
+
+/*
+** Compute a bloom filter hash using pOp->p4.i registers from aMem[] beginning
+** with pOp->p3.  Return the hash.
+*/
+static u64 filterHash(const Mem *aMem, const Op *pOp){
+  int i, mx;
+  u64 h = 0;
+
+  assert( pOp->p4type==P4_INT32 );
+  for(i=pOp->p3, mx=i+pOp->p4.i; i<mx; i++){
+    const Mem *p = &aMem[i];
+    if( p->flags & (MEM_Int|MEM_IntReal) ){
+      h += p->u.i;
+    }else if( p->flags & MEM_Real ){
+      h += sqlite3VdbeIntValue(p);
+    }else if( p->flags & (MEM_Str|MEM_Blob) ){
+      /* All strings have the same hash and all blobs have the same hash,
+      ** though, at least, those hashes are different from each other and
+      ** from NULL. */
+      h += 4093 + (p->flags & (MEM_Str|MEM_Blob));
+    }
+  }
+  return h;
+}
+
+
+/*
+** For OP_Column, factor out the case where content is loaded from
+** overflow pages, so that the code to implement this case is separate
+** the common case where all content fits on the page.  Factoring out
+** the code reduces register pressure and helps the common case
+** to run faster.
+*/
+static SQLITE_NOINLINE int vdbeColumnFromOverflow(
+  VdbeCursor *pC,       /* The BTree cursor from which we are reading */
+  int iCol,             /* The column to read */
+  int t,                /* The serial-type code for the column value */
+  i64 iOffset,          /* Offset to the start of the content value */
+  u32 cacheStatus,      /* Current Vdbe.cacheCtr value */
+  u32 colCacheCtr,      /* Current value of the column cache counter */
+  Mem *pDest            /* Store the value into this register. */
+){
+  int rc;
+  sqlite3 *db = pDest->db;
+  int encoding = pDest->enc;
+  int len = sqlite3VdbeSerialTypeLen(t);
+  assert( pC->eCurType==CURTYPE_BTREE );
+  if( len>db->aLimit[SQLITE_LIMIT_LENGTH] ) return SQLITE_TOOBIG;
+  if( len > 4000 && pC->pKeyInfo==0 ){
+    /* Cache large column values that are on overflow pages using
+    ** an RCStr (reference counted string) so that if they are reloaded,
+    ** that do not have to be copied a second time.  The overhead of
+    ** creating and managing the cache is such that this is only
+    ** profitable for larger TEXT and BLOB values.
+    **
+    ** Only do this on table-btrees so that writes to index-btrees do not
+    ** need to clear the cache.  This buys performance in the common case
+    ** in exchange for generality.
+    */
+    VdbeTxtBlbCache *pCache;
+    char *pBuf;
+    if( pC->colCache==0 ){
+      pC->pCache = sqlite3DbMallocZero(db, sizeof(VdbeTxtBlbCache) );
+      if( pC->pCache==0 ) return SQLITE_NOMEM;
+      pC->colCache = 1;
+    }
+    pCache = pC->pCache;
+    if( pCache->pCValue==0
+     || pCache->iCol!=iCol
+     || pCache->cacheStatus!=cacheStatus
+     || pCache->colCacheCtr!=colCacheCtr
+     || pCache->iOffset!=sqlite3BtreeOffset(pC->uc.pCursor)
+    ){
+      if( pCache->pCValue ) sqlite3RCStrUnref(pCache->pCValue);
+      pBuf = pCache->pCValue = sqlite3RCStrNew( len+3 );
+      if( pBuf==0 ) return SQLITE_NOMEM;
+      rc = sqlite3BtreePayload(pC->uc.pCursor, iOffset, len, pBuf);
+      if( rc ) return rc;
+      pBuf[len] = 0;
+      pBuf[len+1] = 0;
+      pBuf[len+2] = 0;
+      pCache->iCol = iCol;
+      pCache->cacheStatus = cacheStatus;
+      pCache->colCacheCtr = colCacheCtr;
+      pCache->iOffset = sqlite3BtreeOffset(pC->uc.pCursor);
+    }else{
+      pBuf = pCache->pCValue;
+    }
+    assert( t>=12 );
+    sqlite3RCStrRef(pBuf);
+    if( t&1 ){
+      rc = sqlite3VdbeMemSetStr(pDest, pBuf, len, encoding,
+                                sqlite3RCStrUnref);
+      pDest->flags |= MEM_Term;
+    }else{
+      rc = sqlite3VdbeMemSetStr(pDest, pBuf, len, 0,
+                                sqlite3RCStrUnref);
+    }
+  }else{
+    rc = sqlite3VdbeMemFromBtree(pC->uc.pCursor, iOffset, len, pDest);
+    if( rc ) return rc;
+    sqlite3VdbeSerialGet((const u8*)pDest->z, t, pDest);
+    if( (t&1)!=0 && encoding==SQLITE_UTF8 ){
+      pDest->z[len] = 0;
+      pDest->flags |= MEM_Term;
+    }
+  }
+  pDest->flags &= ~MEM_Ephem;
+  return rc;
+}
+
+
+/*
+** Return the symbolic name for the data type of a pMem
+*/
+static const char *vdbeMemTypeName(Mem *pMem){
+  static const char *azTypes[] = {
+      /* SQLITE_INTEGER */ "INT",
+      /* SQLITE_FLOAT   */ "REAL",
+      /* SQLITE_TEXT    */ "TEXT",
+      /* SQLITE_BLOB    */ "BLOB",
+      /* SQLITE_NULL    */ "NULL"
+  };
+  return azTypes[sqlite3_value_type(pMem)-1];
+}
+
+/*
+** Execute as much of a VDBE program as we can.
+** This is the core of sqlite3_step().
+*/
+SQLITE_PRIVATE int sqlite3VdbeExec(
+  Vdbe *p                    /* The VDBE */
+){
+  Op *aOp = p->aOp;          /* Copy of p->aOp */
+  Op *pOp = aOp;             /* Current operation */
+#ifdef SQLITE_DEBUG
+  Op *pOrigOp;               /* Value of pOp at the top of the loop */
+  int nExtraDelete = 0;      /* Verifies FORDELETE and AUXDELETE flags */
+  u8 iCompareIsInit = 0;     /* iCompare is initialized */
+#endif
+  int rc = SQLITE_OK;        /* Value to return */
+  sqlite3 *db = p->db;       /* The database */
+  u8 resetSchemaOnFault = 0; /* Reset schema after an error if positive */
+  u8 encoding = ENC(db);     /* The database encoding */
+  int iCompare = 0;          /* Result of last comparison */
+  u64 nVmStep = 0;           /* Number of virtual machine steps */
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  u64 nProgressLimit;        /* Invoke xProgress() when nVmStep reaches this */
+#endif
+  Mem *aMem = p->aMem;       /* Copy of p->aMem */
+  Mem *pIn1 = 0;             /* 1st input operand */
+  Mem *pIn2 = 0;             /* 2nd input operand */
+  Mem *pIn3 = 0;             /* 3rd input operand */
+  Mem *pOut = 0;             /* Output operand */
+  u32 colCacheCtr = 0;       /* Column cache counter */
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
+  u64 *pnCycle = 0;
+  int bStmtScanStatus = IS_STMT_SCANSTATUS(db)!=0;
+#endif
+  /*** INSERT STACK UNION HERE ***/
+
+  assert( p->eVdbeState==VDBE_RUN_STATE );  /* sqlite3_step() verifies this */
+  if( DbMaskNonZero(p->lockMask) ){
+    sqlite3VdbeEnter(p);
+  }
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  if( db->xProgress ){
+    u32 iPrior = p->aCounter[SQLITE_STMTSTATUS_VM_STEP];
+    assert( 0 < db->nProgressOps );
+    nProgressLimit = db->nProgressOps - (iPrior % db->nProgressOps);
+  }else{
+    nProgressLimit = LARGEST_UINT64;
+  }
+#endif
+  if( p->rc==SQLITE_NOMEM ){
+    /* This happens if a malloc() inside a call to sqlite3_column_text() or
+    ** sqlite3_column_text16() failed.  */
+    goto no_mem;
+  }
+  assert( p->rc==SQLITE_OK || (p->rc&0xff)==SQLITE_BUSY );
+  testcase( p->rc!=SQLITE_OK );
+  p->rc = SQLITE_OK;
+  assert( p->bIsReader || p->readOnly!=0 );
+  p->iCurrentTime = 0;
+  assert( p->explain==0 );
+  db->busyHandler.nBusy = 0;
+  if( AtomicLoad(&db->u1.isInterrupted) ) goto abort_due_to_interrupt;
+  sqlite3VdbeIOTraceSql(p);
+#ifdef SQLITE_DEBUG
+  sqlite3BeginBenignMalloc();
+  if( p->pc==0
+   && (p->db->flags & (SQLITE_VdbeListing|SQLITE_VdbeEQP|SQLITE_VdbeTrace))!=0
+  ){
+    int i;
+    int once = 1;
+    sqlite3VdbePrintSql(p);
+    if( p->db->flags & SQLITE_VdbeListing ){
+      printf("VDBE Program Listing:\n");
+      for(i=0; i<p->nOp; i++){
+        sqlite3VdbePrintOp(stdout, i, &aOp[i]);
+      }
+    }
+    if( p->db->flags & SQLITE_VdbeEQP ){
+      for(i=0; i<p->nOp; i++){
+        if( aOp[i].opcode==OP_Explain ){
+          if( once ) printf("VDBE Query Plan:\n");
+          printf("%s\n", aOp[i].p4.z);
+          once = 0;
+        }
+      }
+    }
+    if( p->db->flags & SQLITE_VdbeTrace )  printf("VDBE Trace:\n");
+  }
+  sqlite3EndBenignMalloc();
+#endif
+  for(pOp=&aOp[p->pc]; 1; pOp++){
+    /* Errors are detected by individual opcodes, with an immediate
+    ** jumps to abort_due_to_error. */
+    assert( rc==SQLITE_OK );
+
+    assert( pOp>=aOp && pOp<&aOp[p->nOp]);
+    nVmStep++;
+
+#if defined(VDBE_PROFILE)
+    pOp->nExec++;
+    pnCycle = &pOp->nCycle;
+    if( sqlite3NProfileCnt==0 ) *pnCycle -= sqlite3Hwtime();
+#elif defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+    if( bStmtScanStatus ){
+      pOp->nExec++;
+      pnCycle = &pOp->nCycle;
+      *pnCycle -= sqlite3Hwtime();
+    }
+#endif
+
+    /* Only allow tracing if SQLITE_DEBUG is defined.
+    */
+#ifdef SQLITE_DEBUG
+    if( db->flags & SQLITE_VdbeTrace ){
+      sqlite3VdbePrintOp(stdout, (int)(pOp - aOp), pOp);
+      test_trace_breakpoint((int)(pOp - aOp),pOp,p);
+    }
+#endif
+
+
+    /* Check to see if we need to simulate an interrupt.  This only happens
+    ** if we have a special test build.
+    */
+#ifdef SQLITE_TEST
+    if( sqlite3_interrupt_count>0 ){
+      sqlite3_interrupt_count--;
+      if( sqlite3_interrupt_count==0 ){
+        sqlite3_interrupt(db);
+      }
+    }
+#endif
+
+    /* Sanity checking on other operands */
+#ifdef SQLITE_DEBUG
+    {
+      u8 opProperty = sqlite3OpcodeProperty[pOp->opcode];
+      if( (opProperty & OPFLG_IN1)!=0 ){
+        assert( pOp->p1>0 );
+        assert( pOp->p1<=(p->nMem+1 - p->nCursor) );
+        assert( memIsValid(&aMem[pOp->p1]) );
+        assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p1]) );
+        REGISTER_TRACE(pOp->p1, &aMem[pOp->p1]);
+      }
+      if( (opProperty & OPFLG_IN2)!=0 ){
+        assert( pOp->p2>0 );
+        assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
+        assert( memIsValid(&aMem[pOp->p2]) );
+        assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p2]) );
+        REGISTER_TRACE(pOp->p2, &aMem[pOp->p2]);
+      }
+      if( (opProperty & OPFLG_IN3)!=0 ){
+        assert( pOp->p3>0 );
+        assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+        assert( memIsValid(&aMem[pOp->p3]) );
+        assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p3]) );
+        REGISTER_TRACE(pOp->p3, &aMem[pOp->p3]);
+      }
+      if( (opProperty & OPFLG_OUT2)!=0 ){
+        assert( pOp->p2>0 );
+        assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
+        memAboutToChange(p, &aMem[pOp->p2]);
+      }
+      if( (opProperty & OPFLG_OUT3)!=0 ){
+        assert( pOp->p3>0 );
+        assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+        memAboutToChange(p, &aMem[pOp->p3]);
+      }
+    }
+#endif
+#ifdef SQLITE_DEBUG
+    pOrigOp = pOp;
+#endif
+
+    switch( pOp->opcode ){
+
+/*****************************************************************************
+** What follows is a massive switch statement where each case implements a
+** separate instruction in the virtual machine.  If we follow the usual
+** indentation conventions, each case should be indented by 6 spaces.  But
+** that is a lot of wasted space on the left margin.  So the code within
+** the switch statement will break with convention and be flush-left. Another
+** big comment (similar to this one) will mark the point in the code where
+** we transition back to normal indentation.
+**
+** The formatting of each case is important.  The makefile for SQLite
+** generates two C files "opcodes.h" and "opcodes.c" by scanning this
+** file looking for lines that begin with "case OP_".  The opcodes.h files
+** will be filled with #defines that give unique integer values to each
+** opcode and the opcodes.c file is filled with an array of strings where
+** each string is the symbolic name for the corresponding opcode.  If the
+** case statement is followed by a comment of the form "/# same as ... #/"
+** that comment is used to determine the particular value of the opcode.
+**
+** Other keywords in the comment that follows each case are used to
+** construct the OPFLG_INITIALIZER value that initializes opcodeProperty[].
+** Keywords include: in1, in2, in3, out2, out3.  See
+** the mkopcodeh.awk script for additional information.
+**
+** Documentation about VDBE opcodes is generated by scanning this file
+** for lines of that contain "Opcode:".  That line and all subsequent
+** comment lines are used in the generation of the opcode.html documentation
+** file.
+**
+** SUMMARY:
+**
+**     Formatting is important to scripts that scan this file.
+**     Do not deviate from the formatting style currently in use.
+**
+*****************************************************************************/
+
+/* Opcode:  Goto * P2 * * *
+**
+** An unconditional jump to address P2.
+** The next instruction executed will be
+** the one at index P2 from the beginning of
+** the program.
+**
+** The P1 parameter is not actually used by this opcode.  However, it
+** is sometimes set to 1 instead of 0 as a hint to the command-line shell
+** that this Goto is the bottom of a loop and that the lines from P2 down
+** to the current line should be indented for EXPLAIN output.
+*/
+case OP_Goto: {             /* jump */
+
+#ifdef SQLITE_DEBUG
+  /* In debugging mode, when the p5 flags is set on an OP_Goto, that
+  ** means we should really jump back to the preceding OP_ReleaseReg
+  ** instruction. */
+  if( pOp->p5 ){
+    assert( pOp->p2 < (int)(pOp - aOp) );
+    assert( pOp->p2 > 1 );
+    pOp = &aOp[pOp->p2 - 2];
+    assert( pOp[1].opcode==OP_ReleaseReg );
+    goto check_for_interrupt;
+  }
+#endif
+
+jump_to_p2_and_check_for_interrupt:
+  pOp = &aOp[pOp->p2 - 1];
+
+  /* Opcodes that are used as the bottom of a loop (OP_Next, OP_Prev,
+  ** OP_VNext, or OP_SorterNext) all jump here upon
+  ** completion.  Check to see if sqlite3_interrupt() has been called
+  ** or if the progress callback needs to be invoked.
+  **
+  ** This code uses unstructured "goto" statements and does not look clean.
+  ** But that is not due to sloppy coding habits. The code is written this
+  ** way for performance, to avoid having to run the interrupt and progress
+  ** checks on every opcode.  This helps sqlite3_step() to run about 1.5%
+  ** faster according to "valgrind --tool=cachegrind" */
+check_for_interrupt:
+  if( AtomicLoad(&db->u1.isInterrupted) ) goto abort_due_to_interrupt;
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  /* Call the progress callback if it is configured and the required number
+  ** of VDBE ops have been executed (either since this invocation of
+  ** sqlite3VdbeExec() or since last time the progress callback was called).
+  ** If the progress callback returns non-zero, exit the virtual machine with
+  ** a return code SQLITE_ABORT.
+  */
+  while( nVmStep>=nProgressLimit && db->xProgress!=0 ){
+    assert( db->nProgressOps!=0 );
+    nProgressLimit += db->nProgressOps;
+    if( db->xProgress(db->pProgressArg) ){
+      nProgressLimit = LARGEST_UINT64;
+      rc = SQLITE_INTERRUPT;
+      goto abort_due_to_error;
+    }
+  }
+#endif
+
+  break;
+}
+
+/* Opcode:  Gosub P1 P2 * * *
+**
+** Write the current address onto register P1
+** and then jump to address P2.
+*/
+case OP_Gosub: {            /* jump */
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  pIn1 = &aMem[pOp->p1];
+  assert( VdbeMemDynamic(pIn1)==0 );
+  memAboutToChange(p, pIn1);
+  pIn1->flags = MEM_Int;
+  pIn1->u.i = (int)(pOp-aOp);
+  REGISTER_TRACE(pOp->p1, pIn1);
+  goto jump_to_p2_and_check_for_interrupt;
+}
+
+/* Opcode:  Return P1 P2 P3 * *
+**
+** Jump to the address stored in register P1.  If P1 is a return address
+** register, then this accomplishes a return from a subroutine.
+**
+** If P3 is 1, then the jump is only taken if register P1 holds an integer
+** values, otherwise execution falls through to the next opcode, and the
+** OP_Return becomes a no-op. If P3 is 0, then register P1 must hold an
+** integer or else an assert() is raised.  P3 should be set to 1 when
+** this opcode is used in combination with OP_BeginSubrtn, and set to 0
+** otherwise.
+**
+** The value in register P1 is unchanged by this opcode.
+**
+** P2 is not used by the byte-code engine.  However, if P2 is positive
+** and also less than the current address, then the "EXPLAIN" output
+** formatter in the CLI will indent all opcodes from the P2 opcode up
+** to be not including the current Return.   P2 should be the first opcode
+** in the subroutine from which this opcode is returning.  Thus the P2
+** value is a byte-code indentation hint.  See tag-20220407a in
+** wherecode.c and shell.c.
+*/
+case OP_Return: {           /* in1 */
+  pIn1 = &aMem[pOp->p1];
+  if( pIn1->flags & MEM_Int ){
+    if( pOp->p3 ){ VdbeBranchTaken(1, 2); }
+    pOp = &aOp[pIn1->u.i];
+  }else if( ALWAYS(pOp->p3) ){
+    VdbeBranchTaken(0, 2);
+  }
+  break;
+}
+
+/* Opcode: InitCoroutine P1 P2 P3 * *
+**
+** Set up register P1 so that it will Yield to the coroutine
+** located at address P3.
+**
+** If P2!=0 then the coroutine implementation immediately follows
+** this opcode.  So jump over the coroutine implementation to
+** address P2.
+**
+** See also: EndCoroutine
+*/
+case OP_InitCoroutine: {     /* jump0 */
+  assert( pOp->p1>0 &&  pOp->p1<=(p->nMem+1 - p->nCursor) );
+  assert( pOp->p2>=0 && pOp->p2<p->nOp );
+  assert( pOp->p3>=0 && pOp->p3<p->nOp );
+  pOut = &aMem[pOp->p1];
+  assert( !VdbeMemDynamic(pOut) );
+  pOut->u.i = pOp->p3 - 1;
+  pOut->flags = MEM_Int;
+  if( pOp->p2==0 ) break;
+
+  /* Most jump operations do a goto to this spot in order to update
+  ** the pOp pointer. */
+jump_to_p2:
+  assert( pOp->p2>0 );       /* There are never any jumps to instruction 0 */
+  assert( pOp->p2<p->nOp );  /* Jumps must be in range */
+  pOp = &aOp[pOp->p2 - 1];
+  break;
+}
+
+/* Opcode:  EndCoroutine P1 * * * *
+**
+** The instruction at the address in register P1 is a Yield.
+** Jump to the P2 parameter of that Yield.
+** After the jump, the value register P1 is left with a value
+** such that subsequent OP_Yields go back to the this same
+** OP_EndCoroutine instruction.
+**
+** See also: InitCoroutine
+*/
+case OP_EndCoroutine: {           /* in1 */
+  VdbeOp *pCaller;
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags==MEM_Int );
+  assert( pIn1->u.i>=0 && pIn1->u.i<p->nOp );
+  pCaller = &aOp[pIn1->u.i];
+  assert( pCaller->opcode==OP_Yield );
+  assert( pCaller->p2>=0 && pCaller->p2<p->nOp );
+  pIn1->u.i = (int)(pOp - p->aOp) - 1;
+  pOp = &aOp[pCaller->p2 - 1];
+  break;
+}
+
+/* Opcode:  Yield P1 P2 * * *
+**
+** Swap the program counter with the value in register P1.  This
+** has the effect of yielding to a coroutine.
+**
+** If the coroutine that is launched by this instruction ends with
+** Yield or Return then continue to the next instruction.  But if
+** the coroutine launched by this instruction ends with
+** EndCoroutine, then jump to P2 rather than continuing with the
+** next instruction.
+**
+** See also: InitCoroutine
+*/
+case OP_Yield: {            /* in1, jump0 */
+  int pcDest;
+  pIn1 = &aMem[pOp->p1];
+  assert( VdbeMemDynamic(pIn1)==0 );
+  pIn1->flags = MEM_Int;
+  pcDest = (int)pIn1->u.i;
+  pIn1->u.i = (int)(pOp - aOp);
+  REGISTER_TRACE(pOp->p1, pIn1);
+  pOp = &aOp[pcDest];
+  break;
+}
+
+/* Opcode:  HaltIfNull  P1 P2 P3 P4 P5
+** Synopsis: if r[P3]=null halt
+**
+** Check the value in register P3.  If it is NULL then Halt using
+** parameter P1, P2, and P4 as if this were a Halt instruction.  If the
+** value in register P3 is not NULL, then this routine is a no-op.
+** The P5 parameter should be 1.
+*/
+case OP_HaltIfNull: {      /* in3 */
+  pIn3 = &aMem[pOp->p3];
+#ifdef SQLITE_DEBUG
+  if( pOp->p2==OE_Abort ){ sqlite3VdbeAssertAbortable(p); }
+#endif
+  if( (pIn3->flags & MEM_Null)==0 ) break;
+  /* Fall through into OP_Halt */
+  /* no break */ deliberate_fall_through
+}
+
+/* Opcode:  Halt P1 P2 P3 P4 P5
+**
+** Exit immediately.  All open cursors, etc are closed
+** automatically.
+**
+** P1 is the result code returned by sqlite3_exec(), sqlite3_reset(),
+** or sqlite3_finalize().  For a normal halt, this should be SQLITE_OK (0).
+** For errors, it can be some other value.  If P1!=0 then P2 will determine
+** whether or not to rollback the current transaction.  Do not rollback
+** if P2==OE_Fail. Do the rollback if P2==OE_Rollback.  If P2==OE_Abort,
+** then back out all changes that have occurred during this execution of the
+** VDBE, but do not rollback the transaction.
+**
+** If P3 is not zero and P4 is NULL, then P3 is a register that holds the
+** text of an error message.
+**
+** If P3 is zero and P4 is not null then the error message string is held
+** in P4.
+**
+** P5 is a value between 1 and 4, inclusive, then the P4 error message
+** string is modified as follows:
+**
+**    1:  NOT NULL constraint failed: P4
+**    2:  UNIQUE constraint failed: P4
+**    3:  CHECK constraint failed: P4
+**    4:  FOREIGN KEY constraint failed: P4
+**
+** If P3 is zero and P5 is not zero and P4 is NULL, then everything after
+** the ":" is omitted.
+**
+** There is an implied "Halt 0 0 0" instruction inserted at the very end of
+** every program.  So a jump past the last instruction of the program
+** is the same as executing Halt.
+*/
+case OP_Halt: {
+  VdbeFrame *pFrame;
+  int pcx;
+
+#ifdef SQLITE_DEBUG
+  if( pOp->p2==OE_Abort ){ sqlite3VdbeAssertAbortable(p); }
+#endif
+  assert( pOp->p4type==P4_NOTUSED
+       || pOp->p4type==P4_STATIC
+       || pOp->p4type==P4_DYNAMIC );
+
+  /* A deliberately coded "OP_Halt SQLITE_INTERNAL * * * *" opcode indicates
+  ** something is wrong with the code generator.  Raise an assertion in order
+  ** to bring this to the attention of fuzzers and other testing tools. */
+  assert( pOp->p1!=SQLITE_INTERNAL );
+
+  if( p->pFrame && pOp->p1==SQLITE_OK ){
+    /* Halt the sub-program. Return control to the parent frame. */
+    pFrame = p->pFrame;
+    p->pFrame = pFrame->pParent;
+    p->nFrame--;
+    sqlite3VdbeSetChanges(db, p->nChange);
+    pcx = sqlite3VdbeFrameRestore(pFrame);
+    if( pOp->p2==OE_Ignore ){
+      /* Instruction pcx is the OP_Program that invoked the sub-program
+      ** currently being halted. If the p2 instruction of this OP_Halt
+      ** instruction is set to OE_Ignore, then the sub-program is throwing
+      ** an IGNORE exception. In this case jump to the address specified
+      ** as the p2 of the calling OP_Program.  */
+      pcx = p->aOp[pcx].p2-1;
+    }
+    aOp = p->aOp;
+    aMem = p->aMem;
+    pOp = &aOp[pcx];
+    break;
+  }
+  p->rc = pOp->p1;
+  p->errorAction = (u8)pOp->p2;
+  assert( pOp->p5<=4 );
+  if( p->rc ){
+    if( pOp->p3>0 && pOp->p4type==P4_NOTUSED ){
+      const char *zErr;
+      assert( pOp->p3<=(p->nMem + 1 - p->nCursor) );
+      zErr = sqlite3ValueText(&aMem[pOp->p3], SQLITE_UTF8);
+      sqlite3VdbeError(p, "%s", zErr);
+    }else if( pOp->p5 ){
+      static const char * const azType[] = { "NOT NULL", "UNIQUE", "CHECK",
+                                             "FOREIGN KEY" };
+      testcase( pOp->p5==1 );
+      testcase( pOp->p5==2 );
+      testcase( pOp->p5==3 );
+      testcase( pOp->p5==4 );
+      sqlite3VdbeError(p, "%s constraint failed", azType[pOp->p5-1]);
+      if( pOp->p4.z ){
+        p->zErrMsg = sqlite3MPrintf(db, "%z: %s", p->zErrMsg, pOp->p4.z);
+      }
+    }else{
+      sqlite3VdbeError(p, "%s", pOp->p4.z);
+    }
+    pcx = (int)(pOp - aOp);
+    sqlite3_log(pOp->p1, "abort at %d in [%s]: %s", pcx, p->zSql, p->zErrMsg);
+  }
+  rc = sqlite3VdbeHalt(p);
+  assert( rc==SQLITE_BUSY || rc==SQLITE_OK || rc==SQLITE_ERROR );
+  if( rc==SQLITE_BUSY ){
+    p->rc = SQLITE_BUSY;
+  }else{
+    assert( rc==SQLITE_OK || (p->rc&0xff)==SQLITE_CONSTRAINT );
+    assert( rc==SQLITE_OK || db->nDeferredCons>0 || db->nDeferredImmCons>0 );
+    rc = p->rc ? SQLITE_ERROR : SQLITE_DONE;
+  }
+  goto vdbe_return;
+}
+
+/* Opcode: Integer P1 P2 * * *
+** Synopsis: r[P2]=P1
+**
+** The 32-bit integer value P1 is written into register P2.
+*/
+case OP_Integer: {         /* out2 */
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = pOp->p1;
+  break;
+}
+
+/* Opcode: Int64 * P2 * P4 *
+** Synopsis: r[P2]=P4
+**
+** P4 is a pointer to a 64-bit integer value.
+** Write that value into register P2.
+*/
+case OP_Int64: {           /* out2 */
+  pOut = out2Prerelease(p, pOp);
+  assert( pOp->p4.pI64!=0 );
+  pOut->u.i = *pOp->p4.pI64;
+  break;
+}
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/* Opcode: Real * P2 * P4 *
+** Synopsis: r[P2]=P4
+**
+** P4 is a pointer to a 64-bit floating point value.
+** Write that value into register P2.
+*/
+case OP_Real: {            /* same as TK_FLOAT, out2 */
+  pOut = out2Prerelease(p, pOp);
+  pOut->flags = MEM_Real;
+  assert( !sqlite3IsNaN(*pOp->p4.pReal) );
+  pOut->u.r = *pOp->p4.pReal;
+  break;
+}
+#endif
+
+/* Opcode: String8 * P2 * P4 *
+** Synopsis: r[P2]='P4'
+**
+** P4 points to a nul terminated UTF-8 string. This opcode is transformed
+** into a String opcode before it is executed for the first time.  During
+** this transformation, the length of string P4 is computed and stored
+** as the P1 parameter.
+*/
+case OP_String8: {         /* same as TK_STRING, out2 */
+  assert( pOp->p4.z!=0 );
+  pOut = out2Prerelease(p, pOp);
+  pOp->p1 = sqlite3Strlen30(pOp->p4.z);
+
+#ifndef SQLITE_OMIT_UTF16
+  if( encoding!=SQLITE_UTF8 ){
+    rc = sqlite3VdbeMemSetStr(pOut, pOp->p4.z, -1, SQLITE_UTF8, SQLITE_STATIC);
+    assert( rc==SQLITE_OK || rc==SQLITE_TOOBIG );
+    if( rc ) goto too_big;
+    if( SQLITE_OK!=sqlite3VdbeChangeEncoding(pOut, encoding) ) goto no_mem;
+    assert( pOut->szMalloc>0 && pOut->zMalloc==pOut->z );
+    assert( VdbeMemDynamic(pOut)==0 );
+    pOut->szMalloc = 0;
+    pOut->flags |= MEM_Static;
+    if( pOp->p4type==P4_DYNAMIC ){
+      sqlite3DbFree(db, pOp->p4.z);
+    }
+    pOp->p4type = P4_DYNAMIC;
+    pOp->p4.z = pOut->z;
+    pOp->p1 = pOut->n;
+  }
+#endif
+  if( pOp->p1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+  pOp->opcode = OP_String;
+  assert( rc==SQLITE_OK );
+  /* Fall through to the next case, OP_String */
+  /* no break */ deliberate_fall_through
+}
+
+/* Opcode: String P1 P2 P3 P4 P5
+** Synopsis: r[P2]='P4' (len=P1)
+**
+** The string value P4 of length P1 (bytes) is stored in register P2.
+**
+** If P3 is not zero and the content of register P3 is equal to P5, then
+** the datatype of the register P2 is converted to BLOB.  The content is
+** the same sequence of bytes, it is merely interpreted as a BLOB instead
+** of a string, as if it had been CAST.  In other words:
+**
+** if( P3!=0 and reg[P3]==P5 ) reg[P2] := CAST(reg[P2] as BLOB)
+*/
+case OP_String: {          /* out2 */
+  assert( pOp->p4.z!=0 );
+  pOut = out2Prerelease(p, pOp);
+  pOut->flags = MEM_Str|MEM_Static|MEM_Term;
+  pOut->z = pOp->p4.z;
+  pOut->n = pOp->p1;
+  pOut->enc = encoding;
+  UPDATE_MAX_BLOBSIZE(pOut);
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+  if( pOp->p3>0 ){
+    assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+    pIn3 = &aMem[pOp->p3];
+    assert( pIn3->flags & MEM_Int );
+    if( pIn3->u.i==pOp->p5 ) pOut->flags = MEM_Blob|MEM_Static|MEM_Term;
+  }
+#endif
+  break;
+}
+
+/* Opcode: BeginSubrtn * P2 * * *
+** Synopsis: r[P2]=NULL
+**
+** Mark the beginning of a subroutine that can be entered in-line
+** or that can be called using OP_Gosub.  The subroutine should
+** be terminated by an OP_Return instruction that has a P1 operand that
+** is the same as the P2 operand to this opcode and that has P3 set to 1.
+** If the subroutine is entered in-line, then the OP_Return will simply
+** fall through.  But if the subroutine is entered using OP_Gosub, then
+** the OP_Return will jump back to the first instruction after the OP_Gosub.
+**
+** This routine works by loading a NULL into the P2 register.  When the
+** return address register contains a NULL, the OP_Return instruction is
+** a no-op that simply falls through to the next instruction (assuming that
+** the OP_Return opcode has a P3 value of 1).  Thus if the subroutine is
+** entered in-line, then the OP_Return will cause in-line execution to
+** continue.  But if the subroutine is entered via OP_Gosub, then the
+** OP_Return will cause a return to the address following the OP_Gosub.
+**
+** This opcode is identical to OP_Null.  It has a different name
+** only to make the byte code easier to read and verify.
+*/
+/* Opcode: Null P1 P2 P3 * *
+** Synopsis: r[P2..P3]=NULL
+**
+** Write a NULL into registers P2.  If P3 greater than P2, then also write
+** NULL into register P3 and every register in between P2 and P3.  If P3
+** is less than P2 (typically P3 is zero) then only register P2 is
+** set to NULL.
+**
+** If the P1 value is non-zero, then also set the MEM_Cleared flag so that
+** NULL values will not compare equal even if SQLITE_NULLEQ is set on
+** OP_Ne or OP_Eq.
+*/
+case OP_BeginSubrtn:
+case OP_Null: {           /* out2 */
+  int cnt;
+  u16 nullFlag;
+  pOut = out2Prerelease(p, pOp);
+  cnt = pOp->p3-pOp->p2;
+  assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+  pOut->flags = nullFlag = pOp->p1 ? (MEM_Null|MEM_Cleared) : MEM_Null;
+  pOut->n = 0;
+#ifdef SQLITE_DEBUG
+  pOut->uTemp = 0;
+#endif
+  while( cnt>0 ){
+    pOut++;
+    memAboutToChange(p, pOut);
+    sqlite3VdbeMemSetNull(pOut);
+    pOut->flags = nullFlag;
+    pOut->n = 0;
+    cnt--;
+  }
+  break;
+}
+
+/* Opcode: SoftNull P1 * * * *
+** Synopsis: r[P1]=NULL
+**
+** Set register P1 to have the value NULL as seen by the OP_MakeRecord
+** instruction, but do not free any string or blob memory associated with
+** the register, so that if the value was a string or blob that was
+** previously copied using OP_SCopy, the copies will continue to be valid.
+*/
+case OP_SoftNull: {
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  pOut = &aMem[pOp->p1];
+  pOut->flags = (pOut->flags&~(MEM_Undefined|MEM_AffMask))|MEM_Null;
+  break;
+}
+
+/* Opcode: Blob P1 P2 * P4 *
+** Synopsis: r[P2]=P4 (len=P1)
+**
+** P4 points to a blob of data P1 bytes long.  Store this
+** blob in register P2.  If P4 is a NULL pointer, then construct
+** a zero-filled blob that is P1 bytes long in P2.
+*/
+case OP_Blob: {                /* out2 */
+  assert( pOp->p1 <= SQLITE_MAX_LENGTH );
+  pOut = out2Prerelease(p, pOp);
+  if( pOp->p4.z==0 ){
+    sqlite3VdbeMemSetZeroBlob(pOut, pOp->p1);
+    if( sqlite3VdbeMemExpandBlob(pOut) ) goto no_mem;
+  }else{
+    sqlite3VdbeMemSetStr(pOut, pOp->p4.z, pOp->p1, 0, 0);
+  }
+  pOut->enc = encoding;
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Variable P1 P2 * * *
+** Synopsis: r[P2]=parameter(P1)
+**
+** Transfer the values of bound parameter P1 into register P2
+*/
+case OP_Variable: {            /* out2 */
+  Mem *pVar;       /* Value being transferred */
+
+  assert( pOp->p1>0 && pOp->p1<=p->nVar );
+  pVar = &p->aVar[pOp->p1 - 1];
+  if( sqlite3VdbeMemTooBig(pVar) ){
+    goto too_big;
+  }
+  pOut = &aMem[pOp->p2];
+  if( VdbeMemDynamic(pOut) ) sqlite3VdbeMemSetNull(pOut);
+  memcpy(pOut, pVar, MEMCELLSIZE);
+  pOut->flags &= ~(MEM_Dyn|MEM_Ephem);
+  pOut->flags |= MEM_Static|MEM_FromBind;
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Move P1 P2 P3 * *
+** Synopsis: r[P2@P3]=r[P1@P3]
+**
+** Move the P3 values in register P1..P1+P3-1 over into
+** registers P2..P2+P3-1.  Registers P1..P1+P3-1 are
+** left holding a NULL.  It is an error for register ranges
+** P1..P1+P3-1 and P2..P2+P3-1 to overlap.  It is an error
+** for P3 to be less than 1.
+*/
+case OP_Move: {
+  int n;           /* Number of registers left to copy */
+  int p1;          /* Register to copy from */
+  int p2;          /* Register to copy to */
+
+  n = pOp->p3;
+  p1 = pOp->p1;
+  p2 = pOp->p2;
+  assert( n>0 && p1>0 && p2>0 );
+  assert( p1+n<=p2 || p2+n<=p1 );
+
+  pIn1 = &aMem[p1];
+  pOut = &aMem[p2];
+  do{
+    assert( pOut<=&aMem[(p->nMem+1 - p->nCursor)] );
+    assert( pIn1<=&aMem[(p->nMem+1 - p->nCursor)] );
+    assert( memIsValid(pIn1) );
+    memAboutToChange(p, pOut);
+    sqlite3VdbeMemMove(pOut, pIn1);
+#ifdef SQLITE_DEBUG
+    pIn1->pScopyFrom = 0;
+    { int i;
+      for(i=1; i<p->nMem; i++){
+        if( aMem[i].pScopyFrom==pIn1 ){
+          assert( aMem[i].bScopy );
+          aMem[i].pScopyFrom = pOut;
+        }
+      }
+    }
+#endif
+    Deephemeralize(pOut);
+    REGISTER_TRACE(p2++, pOut);
+    pIn1++;
+    pOut++;
+  }while( --n );
+  break;
+}
+
+/* Opcode: Copy P1 P2 P3 * P5
+** Synopsis: r[P2@P3+1]=r[P1@P3+1]
+**
+** Make a copy of registers P1..P1+P3 into registers P2..P2+P3.
+**
+** If the 0x0002 bit of P5 is set then also clear the MEM_Subtype flag in the
+** destination.  The 0x0001 bit of P5 indicates that this Copy opcode cannot
+** be merged.  The 0x0001 bit is used by the query planner and does not
+** come into play during query execution.
+**
+** This instruction makes a deep copy of the value.  A duplicate
+** is made of any string or blob constant.  See also OP_SCopy.
+*/
+case OP_Copy: {
+  int n;
+
+  n = pOp->p3;
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  assert( pOut!=pIn1 );
+  while( 1 ){
+    memAboutToChange(p, pOut);
+    sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
+    Deephemeralize(pOut);
+    if( (pOut->flags & MEM_Subtype)!=0 &&  (pOp->p5 & 0x0002)!=0 ){
+      pOut->flags &= ~MEM_Subtype;
+    }
+#ifdef SQLITE_DEBUG
+    pOut->pScopyFrom = 0;
+#endif
+    REGISTER_TRACE(pOp->p2+pOp->p3-n, pOut);
+    if( (n--)==0 ) break;
+    pOut++;
+    pIn1++;
+  }
+  break;
+}
+
+/* Opcode: SCopy P1 P2 * * *
+** Synopsis: r[P2]=r[P1]
+**
+** Make a shallow copy of register P1 into register P2.
+**
+** This instruction makes a shallow copy of the value.  If the value
+** is a string or blob, then the copy is only a pointer to the
+** original and hence if the original changes so will the copy.
+** Worse, if the original is deallocated, the copy becomes invalid.
+** Thus the program must guarantee that the original will not change
+** during the lifetime of the copy.  Use OP_Copy to make a complete
+** copy.
+*/
+case OP_SCopy: {            /* out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  assert( pOut!=pIn1 );
+  sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
+#ifdef SQLITE_DEBUG
+  pOut->pScopyFrom = pIn1;
+  pOut->mScopyFlags = pIn1->flags;
+  pIn1->bScopy = 1;
+#endif
+  break;
+}
+
+/* Opcode: IntCopy P1 P2 * * *
+** Synopsis: r[P2]=r[P1]
+**
+** Transfer the integer value held in register P1 into register P2.
+**
+** This is an optimized version of SCopy that works only for integer
+** values.
+*/
+case OP_IntCopy: {            /* out2 */
+  pIn1 = &aMem[pOp->p1];
+  assert( (pIn1->flags & MEM_Int)!=0 );
+  pOut = &aMem[pOp->p2];
+  sqlite3VdbeMemSetInt64(pOut, pIn1->u.i);
+  break;
+}
+
+/* Opcode: FkCheck * * * * *
+**
+** Halt with an SQLITE_CONSTRAINT error if there are any unresolved
+** foreign key constraint violations.  If there are no foreign key
+** constraint violations, this is a no-op.
+**
+** FK constraint violations are also checked when the prepared statement
+** exits.  This opcode is used to raise foreign key constraint errors prior
+** to returning results such as a row change count or the result of a
+** RETURNING clause.
+*/
+case OP_FkCheck: {
+  if( (rc = sqlite3VdbeCheckFk(p,0))!=SQLITE_OK ){
+    goto abort_due_to_error;
+  }
+  break;
+}
+
+/* Opcode: ResultRow P1 P2 * * *
+** Synopsis: output=r[P1@P2]
+**
+** The registers P1 through P1+P2-1 contain a single row of
+** results. This opcode causes the sqlite3_step() call to terminate
+** with an SQLITE_ROW return code and it sets up the sqlite3_stmt
+** structure to provide access to the r(P1)..r(P1+P2-1) values as
+** the result row.
+*/
+case OP_ResultRow: {
+  assert( p->nResColumn==pOp->p2 );
+  assert( pOp->p1>0 || CORRUPT_DB );
+  assert( pOp->p1+pOp->p2<=(p->nMem+1 - p->nCursor)+1 );
+
+  p->cacheCtr = (p->cacheCtr + 2)|1;
+  p->pResultRow = &aMem[pOp->p1];
+#ifdef SQLITE_DEBUG
+  {
+    Mem *pMem = p->pResultRow;
+    int i;
+    for(i=0; i<pOp->p2; i++){
+      assert( memIsValid(&pMem[i]) );
+      REGISTER_TRACE(pOp->p1+i, &pMem[i]);
+      /* The registers in the result will not be used again when the
+      ** prepared statement restarts.  This is because sqlite3_column()
+      ** APIs might have caused type conversions of made other changes to
+      ** the register values.  Therefore, we can go ahead and break any
+      ** OP_SCopy dependencies. */
+      pMem[i].pScopyFrom = 0;
+    }
+  }
+#endif
+  if( db->mallocFailed ) goto no_mem;
+  if( db->mTrace & SQLITE_TRACE_ROW ){
+    db->trace.xV2(SQLITE_TRACE_ROW, db->pTraceArg, p, 0);
+  }
+  p->pc = (int)(pOp - aOp) + 1;
+  rc = SQLITE_ROW;
+  goto vdbe_return;
+}
+
+/* Opcode: Concat P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]+r[P1]
+**
+** Add the text in register P1 onto the end of the text in
+** register P2 and store the result in register P3.
+** If either the P1 or P2 text are NULL then store NULL in P3.
+**
+**   P3 = P2 || P1
+**
+** It is illegal for P1 and P3 to be the same register. Sometimes,
+** if P3 is the same register as P2, the implementation is able
+** to avoid a memcpy().
+*/
+case OP_Concat: {           /* same as TK_CONCAT, in1, in2, out3 */
+  i64 nByte;          /* Total size of the output string or blob */
+  u16 flags1;         /* Initial flags for P1 */
+  u16 flags2;         /* Initial flags for P2 */
+
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  pOut = &aMem[pOp->p3];
+  testcase( pOut==pIn2 );
+  assert( pIn1!=pOut );
+  flags1 = pIn1->flags;
+  testcase( flags1 & MEM_Null );
+  testcase( pIn2->flags & MEM_Null );
+  if( (flags1 | pIn2->flags) & MEM_Null ){
+    sqlite3VdbeMemSetNull(pOut);
+    break;
+  }
+  if( (flags1 & (MEM_Str|MEM_Blob))==0 ){
+    if( sqlite3VdbeMemStringify(pIn1,encoding,0) ) goto no_mem;
+    flags1 = pIn1->flags & ~MEM_Str;
+  }else if( (flags1 & MEM_Zero)!=0 ){
+    if( sqlite3VdbeMemExpandBlob(pIn1) ) goto no_mem;
+    flags1 = pIn1->flags & ~MEM_Str;
+  }
+  flags2 = pIn2->flags;
+  if( (flags2 & (MEM_Str|MEM_Blob))==0 ){
+    if( sqlite3VdbeMemStringify(pIn2,encoding,0) ) goto no_mem;
+    flags2 = pIn2->flags & ~MEM_Str;
+  }else if( (flags2 & MEM_Zero)!=0 ){
+    if( sqlite3VdbeMemExpandBlob(pIn2) ) goto no_mem;
+    flags2 = pIn2->flags & ~MEM_Str;
+  }
+  nByte = pIn1->n + pIn2->n;
+  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+  if( sqlite3VdbeMemGrow(pOut, (int)nByte+2, pOut==pIn2) ){
+    goto no_mem;
+  }
+  MemSetTypeFlag(pOut, MEM_Str);
+  if( pOut!=pIn2 ){
+    memcpy(pOut->z, pIn2->z, pIn2->n);
+    assert( (pIn2->flags & MEM_Dyn) == (flags2 & MEM_Dyn) );
+    pIn2->flags = flags2;
+  }
+  memcpy(&pOut->z[pIn2->n], pIn1->z, pIn1->n);
+  assert( (pIn1->flags & MEM_Dyn) == (flags1 & MEM_Dyn) );
+  pIn1->flags = flags1;
+  if( encoding>SQLITE_UTF8 ) nByte &= ~1;
+  pOut->z[nByte]=0;
+  pOut->z[nByte+1] = 0;
+  pOut->flags |= MEM_Term;
+  pOut->n = (int)nByte;
+  pOut->enc = encoding;
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: Add P1 P2 P3 * *
+** Synopsis: r[P3]=r[P1]+r[P2]
+**
+** Add the value in register P1 to the value in register P2
+** and store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Multiply P1 P2 P3 * *
+** Synopsis: r[P3]=r[P1]*r[P2]
+**
+**
+** Multiply the value in register P1 by the value in register P2
+** and store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Subtract P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]-r[P1]
+**
+** Subtract the value in register P1 from the value in register P2
+** and store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: Divide P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]/r[P1]
+**
+** Divide the value in register P1 by the value in register P2
+** and store the result in register P3 (P3=P2/P1). If the value in
+** register P1 is zero, then the result is NULL. If either input is
+** NULL, the result is NULL.
+*/
+/* Opcode: Remainder P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]%r[P1]
+**
+** Compute the remainder after integer register P2 is divided by
+** register P1 and store the result in register P3.
+** If the value in register P1 is zero the result is NULL.
+** If either operand is NULL, the result is NULL.
+*/
+case OP_Add:                   /* same as TK_PLUS, in1, in2, out3 */
+case OP_Subtract:              /* same as TK_MINUS, in1, in2, out3 */
+case OP_Multiply:              /* same as TK_STAR, in1, in2, out3 */
+case OP_Divide:                /* same as TK_SLASH, in1, in2, out3 */
+case OP_Remainder: {           /* same as TK_REM, in1, in2, out3 */
+  u16 type1;      /* Numeric type of left operand */
+  u16 type2;      /* Numeric type of right operand */
+  i64 iA;         /* Integer value of left operand */
+  i64 iB;         /* Integer value of right operand */
+  double rA;      /* Real value of left operand */
+  double rB;      /* Real value of right operand */
+
+  pIn1 = &aMem[pOp->p1];
+  type1 = pIn1->flags;
+  pIn2 = &aMem[pOp->p2];
+  type2 = pIn2->flags;
+  pOut = &aMem[pOp->p3];
+  if( (type1 & type2 & MEM_Int)!=0 ){
+int_math:
+    iA = pIn1->u.i;
+    iB = pIn2->u.i;
+    switch( pOp->opcode ){
+      case OP_Add:       if( sqlite3AddInt64(&iB,iA) ) goto fp_math;  break;
+      case OP_Subtract:  if( sqlite3SubInt64(&iB,iA) ) goto fp_math;  break;
+      case OP_Multiply:  if( sqlite3MulInt64(&iB,iA) ) goto fp_math;  break;
+      case OP_Divide: {
+        if( iA==0 ) goto arithmetic_result_is_null;
+        if( iA==-1 && iB==SMALLEST_INT64 ) goto fp_math;
+        iB /= iA;
+        break;
+      }
+      default: {
+        if( iA==0 ) goto arithmetic_result_is_null;
+        if( iA==-1 ) iA = 1;
+        iB %= iA;
+        break;
+      }
+    }
+    pOut->u.i = iB;
+    MemSetTypeFlag(pOut, MEM_Int);
+  }else if( ((type1 | type2) & MEM_Null)!=0 ){
+    goto arithmetic_result_is_null;
+  }else{
+    type1 = numericType(pIn1);
+    type2 = numericType(pIn2);
+    if( (type1 & type2 & MEM_Int)!=0 ) goto int_math;
+fp_math:
+    rA = sqlite3VdbeRealValue(pIn1);
+    rB = sqlite3VdbeRealValue(pIn2);
+    switch( pOp->opcode ){
+      case OP_Add:         rB += rA;       break;
+      case OP_Subtract:    rB -= rA;       break;
+      case OP_Multiply:    rB *= rA;       break;
+      case OP_Divide: {
+        /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+        if( rA==(double)0 ) goto arithmetic_result_is_null;
+        rB /= rA;
+        break;
+      }
+      default: {
+        iA = sqlite3VdbeIntValue(pIn1);
+        iB = sqlite3VdbeIntValue(pIn2);
+        if( iA==0 ) goto arithmetic_result_is_null;
+        if( iA==-1 ) iA = 1;
+        rB = (double)(iB % iA);
+        break;
+      }
+    }
+#ifdef SQLITE_OMIT_FLOATING_POINT
+    pOut->u.i = rB;
+    MemSetTypeFlag(pOut, MEM_Int);
+#else
+    if( sqlite3IsNaN(rB) ){
+      goto arithmetic_result_is_null;
+    }
+    pOut->u.r = rB;
+    MemSetTypeFlag(pOut, MEM_Real);
+#endif
+  }
+  break;
+
+arithmetic_result_is_null:
+  sqlite3VdbeMemSetNull(pOut);
+  break;
+}
+
+/* Opcode: CollSeq P1 * * P4
+**
+** P4 is a pointer to a CollSeq object. If the next call to a user function
+** or aggregate calls sqlite3GetFuncCollSeq(), this collation sequence will
+** be returned. This is used by the built-in min(), max() and nullif()
+** functions.
+**
+** If P1 is not zero, then it is a register that a subsequent min() or
+** max() aggregate will set to 1 if the current row is not the minimum or
+** maximum.  The P1 register is initialized to 0 by this instruction.
+**
+** The interface used by the implementation of the aforementioned functions
+** to retrieve the collation sequence set by this opcode is not available
+** publicly.  Only built-in functions have access to this feature.
+*/
+case OP_CollSeq: {
+  assert( pOp->p4type==P4_COLLSEQ );
+  if( pOp->p1 ){
+    sqlite3VdbeMemSetInt64(&aMem[pOp->p1], 0);
+  }
+  break;
+}
+
+/* Opcode: BitAnd P1 P2 P3 * *
+** Synopsis: r[P3]=r[P1]&r[P2]
+**
+** Take the bit-wise AND of the values in register P1 and P2 and
+** store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: BitOr P1 P2 P3 * *
+** Synopsis: r[P3]=r[P1]|r[P2]
+**
+** Take the bit-wise OR of the values in register P1 and P2 and
+** store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: ShiftLeft P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]<<r[P1]
+**
+** Shift the integer value in register P2 to the left by the
+** number of bits specified by the integer in register P1.
+** Store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+/* Opcode: ShiftRight P1 P2 P3 * *
+** Synopsis: r[P3]=r[P2]>>r[P1]
+**
+** Shift the integer value in register P2 to the right by the
+** number of bits specified by the integer in register P1.
+** Store the result in register P3.
+** If either input is NULL, the result is NULL.
+*/
+case OP_BitAnd:                 /* same as TK_BITAND, in1, in2, out3 */
+case OP_BitOr:                  /* same as TK_BITOR, in1, in2, out3 */
+case OP_ShiftLeft:              /* same as TK_LSHIFT, in1, in2, out3 */
+case OP_ShiftRight: {           /* same as TK_RSHIFT, in1, in2, out3 */
+  i64 iA;
+  u64 uA;
+  i64 iB;
+  u8 op;
+
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  pOut = &aMem[pOp->p3];
+  if( (pIn1->flags | pIn2->flags) & MEM_Null ){
+    sqlite3VdbeMemSetNull(pOut);
+    break;
+  }
+  iA = sqlite3VdbeIntValue(pIn2);
+  iB = sqlite3VdbeIntValue(pIn1);
+  op = pOp->opcode;
+  if( op==OP_BitAnd ){
+    iA &= iB;
+  }else if( op==OP_BitOr ){
+    iA |= iB;
+  }else if( iB!=0 ){
+    assert( op==OP_ShiftRight || op==OP_ShiftLeft );
+
+    /* If shifting by a negative amount, shift in the other direction */
+    if( iB<0 ){
+      assert( OP_ShiftRight==OP_ShiftLeft+1 );
+      op = 2*OP_ShiftLeft + 1 - op;
+      iB = iB>(-64) ? -iB : 64;
+    }
+
+    if( iB>=64 ){
+      iA = (iA>=0 || op==OP_ShiftLeft) ? 0 : -1;
+    }else{
+      memcpy(&uA, &iA, sizeof(uA));
+      if( op==OP_ShiftLeft ){
+        uA <<= iB;
+      }else{
+        uA >>= iB;
+        /* Sign-extend on a right shift of a negative number */
+        if( iA<0 ) uA |= ((((u64)0xffffffff)<<32)|0xffffffff) << (64-iB);
+      }
+      memcpy(&iA, &uA, sizeof(iA));
+    }
+  }
+  pOut->u.i = iA;
+  MemSetTypeFlag(pOut, MEM_Int);
+  break;
+}
+
+/* Opcode: AddImm  P1 P2 * * *
+** Synopsis: r[P1]=r[P1]+P2
+**
+** Add the constant P2 to the value in register P1.
+** The result is always an integer.
+**
+** To force any register to be an integer, just add 0.
+*/
+case OP_AddImm: {            /* in1 */
+  pIn1 = &aMem[pOp->p1];
+  memAboutToChange(p, pIn1);
+  sqlite3VdbeMemIntegerify(pIn1);
+  *(u64*)&pIn1->u.i += (u64)pOp->p2;
+  break;
+}
+
+/* Opcode: MustBeInt P1 P2 * * *
+**
+** Force the value in register P1 to be an integer.  If the value
+** in P1 is not an integer and cannot be converted into an integer
+** without data loss, then jump immediately to P2, or if P2==0
+** raise an SQLITE_MISMATCH exception.
+*/
+case OP_MustBeInt: {            /* jump0, in1 */
+  pIn1 = &aMem[pOp->p1];
+  if( (pIn1->flags & MEM_Int)==0 ){
+    applyAffinity(pIn1, SQLITE_AFF_NUMERIC, encoding);
+    if( (pIn1->flags & MEM_Int)==0 ){
+      VdbeBranchTaken(1, 2);
+      if( pOp->p2==0 ){
+        rc = SQLITE_MISMATCH;
+        goto abort_due_to_error;
+      }else{
+        goto jump_to_p2;
+      }
+    }
+  }
+  VdbeBranchTaken(0, 2);
+  MemSetTypeFlag(pIn1, MEM_Int);
+  break;
+}
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/* Opcode: RealAffinity P1 * * * *
+**
+** If register P1 holds an integer convert it to a real value.
+**
+** This opcode is used when extracting information from a column that
+** has REAL affinity.  Such column values may still be stored as
+** integers, for space efficiency, but after extraction we want them
+** to have only a real value.
+*/
+case OP_RealAffinity: {                  /* in1 */
+  pIn1 = &aMem[pOp->p1];
+  if( pIn1->flags & (MEM_Int|MEM_IntReal) ){
+    testcase( pIn1->flags & MEM_Int );
+    testcase( pIn1->flags & MEM_IntReal );
+    sqlite3VdbeMemRealify(pIn1);
+    REGISTER_TRACE(pOp->p1, pIn1);
+  }
+  break;
+}
+#endif
+
+#if !defined(SQLITE_OMIT_CAST) || !defined(SQLITE_OMIT_ANALYZE)
+/* Opcode: Cast P1 P2 * * *
+** Synopsis: affinity(r[P1])
+**
+** Force the value in register P1 to be the type defined by P2.
+**
+** <ul>
+** <li> P2=='A' → BLOB
+** <li> P2=='B' → TEXT
+** <li> P2=='C' → NUMERIC
+** <li> P2=='D' → INTEGER
+** <li> P2=='E' → REAL
+** </ul>
+**
+** A NULL value is not changed by this routine.  It remains NULL.
+*/
+case OP_Cast: {                  /* in1 */
+  assert( pOp->p2>=SQLITE_AFF_BLOB && pOp->p2<=SQLITE_AFF_REAL );
+  testcase( pOp->p2==SQLITE_AFF_TEXT );
+  testcase( pOp->p2==SQLITE_AFF_BLOB );
+  testcase( pOp->p2==SQLITE_AFF_NUMERIC );
+  testcase( pOp->p2==SQLITE_AFF_INTEGER );
+  testcase( pOp->p2==SQLITE_AFF_REAL );
+  pIn1 = &aMem[pOp->p1];
+  memAboutToChange(p, pIn1);
+  rc = ExpandBlob(pIn1);
+  if( rc ) goto abort_due_to_error;
+  rc = sqlite3VdbeMemCast(pIn1, pOp->p2, encoding);
+  if( rc ) goto abort_due_to_error;
+  UPDATE_MAX_BLOBSIZE(pIn1);
+  REGISTER_TRACE(pOp->p1, pIn1);
+  break;
+}
+#endif /* SQLITE_OMIT_CAST */
+
+/* Opcode: Eq P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]==r[P1]
+**
+** Compare the values in register P1 and P3.  If reg(P3)==reg(P1) then
+** jump to address P2.
+**
+** The SQLITE_AFF_MASK portion of P5 must be an affinity character -
+** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made
+** to coerce both inputs according to this affinity before the
+** comparison is made. If the SQLITE_AFF_MASK is 0x00, then numeric
+** affinity is used. Note that the affinity conversions are stored
+** back into the input registers P1 and P3.  So this opcode can cause
+** persistent changes to registers P1 and P3.
+**
+** Once any conversions have taken place, and neither value is NULL,
+** the values are compared. If both values are blobs then memcmp() is
+** used to determine the results of the comparison.  If both values
+** are text, then the appropriate collating function specified in
+** P4 is used to do the comparison.  If P4 is not specified then
+** memcmp() is used to compare text string.  If both values are
+** numeric, then a numeric comparison is used. If the two values
+** are of different types, then numbers are considered less than
+** strings and strings are considered less than blobs.
+**
+** If SQLITE_NULLEQ is set in P5 then the result of comparison is always either
+** true or false and is never NULL.  If both operands are NULL then the result
+** of comparison is true.  If either operand is NULL then the result is false.
+** If neither operand is NULL the result is the same as it would be if
+** the SQLITE_NULLEQ flag were omitted from P5.
+**
+** This opcode saves the result of comparison for use by the new
+** OP_Jump opcode.
+*/
+/* Opcode: Ne P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]!=r[P1]
+**
+** This works just like the Eq opcode except that the jump is taken if
+** the operands in registers P1 and P3 are not equal.  See the Eq opcode for
+** additional information.
+*/
+/* Opcode: Lt P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]<r[P1]
+**
+** Compare the values in register P1 and P3.  If reg(P3)<reg(P1) then
+** jump to address P2.
+**
+** If the SQLITE_JUMPIFNULL bit of P5 is set and either reg(P1) or
+** reg(P3) is NULL then the take the jump.  If the SQLITE_JUMPIFNULL
+** bit is clear then fall through if either operand is NULL.
+**
+** The SQLITE_AFF_MASK portion of P5 must be an affinity character -
+** SQLITE_AFF_TEXT, SQLITE_AFF_INTEGER, and so forth. An attempt is made
+** to coerce both inputs according to this affinity before the
+** comparison is made. If the SQLITE_AFF_MASK is 0x00, then numeric
+** affinity is used. Note that the affinity conversions are stored
+** back into the input registers P1 and P3.  So this opcode can cause
+** persistent changes to registers P1 and P3.
+**
+** Once any conversions have taken place, and neither value is NULL,
+** the values are compared. If both values are blobs then memcmp() is
+** used to determine the results of the comparison.  If both values
+** are text, then the appropriate collating function specified in
+** P4 is  used to do the comparison.  If P4 is not specified then
+** memcmp() is used to compare text string.  If both values are
+** numeric, then a numeric comparison is used. If the two values
+** are of different types, then numbers are considered less than
+** strings and strings are considered less than blobs.
+**
+** This opcode saves the result of comparison for use by the new
+** OP_Jump opcode.
+*/
+/* Opcode: Le P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]<=r[P1]
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the content of register P3 is less than or equal to the content of
+** register P1.  See the Lt opcode for additional information.
+*/
+/* Opcode: Gt P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]>r[P1]
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the content of register P3 is greater than the content of
+** register P1.  See the Lt opcode for additional information.
+*/
+/* Opcode: Ge P1 P2 P3 P4 P5
+** Synopsis: IF r[P3]>=r[P1]
+**
+** This works just like the Lt opcode except that the jump is taken if
+** the content of register P3 is greater than or equal to the content of
+** register P1.  See the Lt opcode for additional information.
+*/
+case OP_Eq:               /* same as TK_EQ, jump, in1, in3 */
+case OP_Ne:               /* same as TK_NE, jump, in1, in3 */
+case OP_Lt:               /* same as TK_LT, jump, in1, in3 */
+case OP_Le:               /* same as TK_LE, jump, in1, in3 */
+case OP_Gt:               /* same as TK_GT, jump, in1, in3 */
+case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
+  int res, res2;      /* Result of the comparison of pIn1 against pIn3 */
+  char affinity;      /* Affinity to use for comparison */
+  u16 flags1;         /* Copy of initial value of pIn1->flags */
+  u16 flags3;         /* Copy of initial value of pIn3->flags */
+
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
+  flags1 = pIn1->flags;
+  flags3 = pIn3->flags;
+  if( (flags1 & flags3 & MEM_Int)!=0 ){
+    /* Common case of comparison of two integers */
+    if( pIn3->u.i > pIn1->u.i ){
+      if( sqlite3aGTb[pOp->opcode] ){
+        VdbeBranchTaken(1, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+        goto jump_to_p2;
+      }
+      iCompare = +1;
+      VVA_ONLY( iCompareIsInit = 1; )
+    }else if( pIn3->u.i < pIn1->u.i ){
+      if( sqlite3aLTb[pOp->opcode] ){
+        VdbeBranchTaken(1, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+        goto jump_to_p2;
+      }
+      iCompare = -1;
+      VVA_ONLY( iCompareIsInit = 1; )
+    }else{
+      if( sqlite3aEQb[pOp->opcode] ){
+        VdbeBranchTaken(1, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+        goto jump_to_p2;
+      }
+      iCompare = 0;
+      VVA_ONLY( iCompareIsInit = 1; )
+    }
+    VdbeBranchTaken(0, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+    break;
+  }
+  if( (flags1 | flags3)&MEM_Null ){
+    /* One or both operands are NULL */
+    if( pOp->p5 & SQLITE_NULLEQ ){
+      /* If SQLITE_NULLEQ is set (which will only happen if the operator is
+      ** OP_Eq or OP_Ne) then take the jump or not depending on whether
+      ** or not both operands are null.
+      */
+      assert( (flags1 & MEM_Cleared)==0 );
+      assert( (pOp->p5 & SQLITE_JUMPIFNULL)==0 || CORRUPT_DB );
+      testcase( (pOp->p5 & SQLITE_JUMPIFNULL)!=0 );
+      if( (flags1&flags3&MEM_Null)!=0
+       && (flags3&MEM_Cleared)==0
+      ){
+        res = 0;  /* Operands are equal */
+      }else{
+        res = ((flags3 & MEM_Null) ? -1 : +1);  /* Operands are not equal */
+      }
+    }else{
+      /* SQLITE_NULLEQ is clear and at least one operand is NULL,
+      ** then the result is always NULL.
+      ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
+      */
+      VdbeBranchTaken(2,3);
+      if( pOp->p5 & SQLITE_JUMPIFNULL ){
+        goto jump_to_p2;
+      }
+      iCompare = 1;    /* Operands are not equal */
+      VVA_ONLY( iCompareIsInit = 1; )
+      break;
+    }
+  }else{
+    /* Neither operand is NULL and we couldn't do the special high-speed
+    ** integer comparison case.  So do a general-case comparison. */
+    affinity = pOp->p5 & SQLITE_AFF_MASK;
+    if( affinity>=SQLITE_AFF_NUMERIC ){
+      if( (flags1 | flags3)&MEM_Str ){
+        if( (flags1 & (MEM_Int|MEM_IntReal|MEM_Real|MEM_Str))==MEM_Str ){
+          applyNumericAffinity(pIn1,0);
+          assert( flags3==pIn3->flags || CORRUPT_DB );
+          flags3 = pIn3->flags;
+        }
+        if( (flags3 & (MEM_Int|MEM_IntReal|MEM_Real|MEM_Str))==MEM_Str ){
+          applyNumericAffinity(pIn3,0);
+        }
+      }
+    }else if( affinity==SQLITE_AFF_TEXT && ((flags1 | flags3) & MEM_Str)!=0 ){
+      if( (flags1 & MEM_Str)!=0 ){
+        pIn1->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal);
+      }else if( (flags1&(MEM_Int|MEM_Real|MEM_IntReal))!=0 ){
+        testcase( pIn1->flags & MEM_Int );
+        testcase( pIn1->flags & MEM_Real );
+        testcase( pIn1->flags & MEM_IntReal );
+        sqlite3VdbeMemStringify(pIn1, encoding, 1);
+        testcase( (flags1&MEM_Dyn) != (pIn1->flags&MEM_Dyn) );
+        flags1 = (pIn1->flags & ~MEM_TypeMask) | (flags1 & MEM_TypeMask);
+        if( NEVER(pIn1==pIn3) ) flags3 = flags1 | MEM_Str;
+      }
+      if( (flags3 & MEM_Str)!=0 ){
+        pIn3->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal);
+      }else if( (flags3&(MEM_Int|MEM_Real|MEM_IntReal))!=0 ){
+        testcase( pIn3->flags & MEM_Int );
+        testcase( pIn3->flags & MEM_Real );
+        testcase( pIn3->flags & MEM_IntReal );
+        sqlite3VdbeMemStringify(pIn3, encoding, 1);
+        testcase( (flags3&MEM_Dyn) != (pIn3->flags&MEM_Dyn) );
+        flags3 = (pIn3->flags & ~MEM_TypeMask) | (flags3 & MEM_TypeMask);
+      }
+    }
+    assert( pOp->p4type==P4_COLLSEQ || pOp->p4.pColl==0 );
+    res = sqlite3MemCompare(pIn3, pIn1, pOp->p4.pColl);
+  }
+
+  /* At this point, res is negative, zero, or positive if reg[P1] is
+  ** less than, equal to, or greater than reg[P3], respectively.  Compute
+  ** the answer to this operator in res2, depending on what the comparison
+  ** operator actually is.  The next block of code depends on the fact
+  ** that the 6 comparison operators are consecutive integers in this
+  ** order:  NE, EQ, GT, LE, LT, GE */
+  assert( OP_Eq==OP_Ne+1 ); assert( OP_Gt==OP_Ne+2 ); assert( OP_Le==OP_Ne+3 );
+  assert( OP_Lt==OP_Ne+4 ); assert( OP_Ge==OP_Ne+5 );
+  if( res<0 ){
+    res2 = sqlite3aLTb[pOp->opcode];
+  }else if( res==0 ){
+    res2 = sqlite3aEQb[pOp->opcode];
+  }else{
+    res2 = sqlite3aGTb[pOp->opcode];
+  }
+  iCompare = res;
+  VVA_ONLY( iCompareIsInit = 1; )
+
+  /* Undo any changes made by applyAffinity() to the input registers. */
+  assert( (pIn3->flags & MEM_Dyn) == (flags3 & MEM_Dyn) );
+  pIn3->flags = flags3;
+  assert( (pIn1->flags & MEM_Dyn) == (flags1 & MEM_Dyn) );
+  pIn1->flags = flags1;
+
+  VdbeBranchTaken(res2!=0, (pOp->p5 & SQLITE_NULLEQ)?2:3);
+  if( res2 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: ElseEq * P2 * * *
+**
+** This opcode must follow an OP_Lt or OP_Gt comparison operator.  There
+** can be zero or more OP_ReleaseReg opcodes intervening, but no other
+** opcodes are allowed to occur between this instruction and the previous
+** OP_Lt or OP_Gt.
+**
+** If the result of an OP_Eq comparison on the same two operands as
+** the prior OP_Lt or OP_Gt would have been true, then jump to P2.  If
+** the result of an OP_Eq comparison on the two previous operands
+** would have been false or NULL, then fall through.
+*/
+case OP_ElseEq: {       /* same as TK_ESCAPE, jump */
+
+#ifdef SQLITE_DEBUG
+  /* Verify the preconditions of this opcode - that it follows an OP_Lt or
+  ** OP_Gt with zero or more intervening OP_ReleaseReg opcodes */
+  int iAddr;
+  for(iAddr = (int)(pOp - aOp) - 1; ALWAYS(iAddr>=0); iAddr--){
+    if( aOp[iAddr].opcode==OP_ReleaseReg ) continue;
+    assert( aOp[iAddr].opcode==OP_Lt || aOp[iAddr].opcode==OP_Gt );
+    break;
+  }
+#endif /* SQLITE_DEBUG */
+  assert( iCompareIsInit );
+  VdbeBranchTaken(iCompare==0, 2);
+  if( iCompare==0 ) goto jump_to_p2;
+  break;
+}
+
+
+/* Opcode: Permutation * * * P4 *
+**
+** Set the permutation used by the OP_Compare operator in the next
+** instruction.  The permutation is stored in the P4 operand.
+**
+** The permutation is only valid for the next opcode which must be
+** an OP_Compare that has the OPFLAG_PERMUTE bit set in P5.
+**
+** The first integer in the P4 integer array is the length of the array
+** and does not become part of the permutation.
+*/
+case OP_Permutation: {
+  assert( pOp->p4type==P4_INTARRAY );
+  assert( pOp->p4.ai );
+  assert( pOp[1].opcode==OP_Compare );
+  assert( pOp[1].p5 & OPFLAG_PERMUTE );
+  break;
+}
+
+/* Opcode: Compare P1 P2 P3 P4 P5
+** Synopsis: r[P1@P3] <-> r[P2@P3]
+**
+** Compare two vectors of registers in reg(P1)..reg(P1+P3-1) (call this
+** vector "A") and in reg(P2)..reg(P2+P3-1) ("B").  Save the result of
+** the comparison for use by the next OP_Jump instruct.
+**
+** If P5 has the OPFLAG_PERMUTE bit set, then the order of comparison is
+** determined by the most recent OP_Permutation operator.  If the
+** OPFLAG_PERMUTE bit is clear, then register are compared in sequential
+** order.
+**
+** P4 is a KeyInfo structure that defines collating sequences and sort
+** orders for the comparison.  The permutation applies to registers
+** only.  The KeyInfo elements are used sequentially.
+**
+** The comparison is a sort comparison, so NULLs compare equal,
+** NULLs are less than numbers, numbers are less than strings,
+** and strings are less than blobs.
+**
+** This opcode must be immediately followed by an OP_Jump opcode.
+*/
+case OP_Compare: {
+  int n;
+  int i;
+  int p1;
+  int p2;
+  const KeyInfo *pKeyInfo;
+  u32 idx;
+  CollSeq *pColl;    /* Collating sequence to use on this term */
+  int bRev;          /* True for DESCENDING sort order */
+  u32 *aPermute;     /* The permutation */
+
+  if( (pOp->p5 & OPFLAG_PERMUTE)==0 ){
+    aPermute = 0;
+  }else{
+    assert( pOp>aOp );
+    assert( pOp[-1].opcode==OP_Permutation );
+    assert( pOp[-1].p4type==P4_INTARRAY );
+    aPermute = pOp[-1].p4.ai + 1;
+    assert( aPermute!=0 );
+  }
+  n = pOp->p3;
+  pKeyInfo = pOp->p4.pKeyInfo;
+  assert( n>0 );
+  assert( pKeyInfo!=0 );
+  p1 = pOp->p1;
+  p2 = pOp->p2;
+#ifdef SQLITE_DEBUG
+  if( aPermute ){
+    int k, mx = 0;
+    for(k=0; k<n; k++) if( aPermute[k]>(u32)mx ) mx = aPermute[k];
+    assert( p1>0 && p1+mx<=(p->nMem+1 - p->nCursor)+1 );
+    assert( p2>0 && p2+mx<=(p->nMem+1 - p->nCursor)+1 );
+  }else{
+    assert( p1>0 && p1+n<=(p->nMem+1 - p->nCursor)+1 );
+    assert( p2>0 && p2+n<=(p->nMem+1 - p->nCursor)+1 );
+  }
+#endif /* SQLITE_DEBUG */
+  for(i=0; i<n; i++){
+    idx = aPermute ? aPermute[i] : (u32)i;
+    assert( memIsValid(&aMem[p1+idx]) );
+    assert( memIsValid(&aMem[p2+idx]) );
+    REGISTER_TRACE(p1+idx, &aMem[p1+idx]);
+    REGISTER_TRACE(p2+idx, &aMem[p2+idx]);
+    assert( i<pKeyInfo->nKeyField );
+    pColl = pKeyInfo->aColl[i];
+    bRev = (pKeyInfo->aSortFlags[i] & KEYINFO_ORDER_DESC);
+    iCompare = sqlite3MemCompare(&aMem[p1+idx], &aMem[p2+idx], pColl);
+    VVA_ONLY( iCompareIsInit = 1; )
+    if( iCompare ){
+      if( (pKeyInfo->aSortFlags[i] & KEYINFO_ORDER_BIGNULL)
+       && ((aMem[p1+idx].flags & MEM_Null) || (aMem[p2+idx].flags & MEM_Null))
+      ){
+        iCompare = -iCompare;
+      }
+      if( bRev ) iCompare = -iCompare;
+      break;
+    }
+  }
+  assert( pOp[1].opcode==OP_Jump );
+  break;
+}
+
+/* Opcode: Jump P1 P2 P3 * *
+**
+** Jump to the instruction at address P1, P2, or P3 depending on whether
+** in the most recent OP_Compare instruction the P1 vector was less than,
+** equal to, or greater than the P2 vector, respectively.
+**
+** This opcode must immediately follow an OP_Compare opcode.
+*/
+case OP_Jump: {             /* jump */
+  assert( pOp>aOp && pOp[-1].opcode==OP_Compare );
+  assert( iCompareIsInit );
+  if( iCompare<0 ){
+    VdbeBranchTaken(0,4); pOp = &aOp[pOp->p1 - 1];
+  }else if( iCompare==0 ){
+    VdbeBranchTaken(1,4); pOp = &aOp[pOp->p2 - 1];
+  }else{
+    VdbeBranchTaken(2,4); pOp = &aOp[pOp->p3 - 1];
+  }
+  break;
+}
+
+/* Opcode: And P1 P2 P3 * *
+** Synopsis: r[P3]=(r[P1] && r[P2])
+**
+** Take the logical AND of the values in registers P1 and P2 and
+** write the result into register P3.
+**
+** If either P1 or P2 is 0 (false) then the result is 0 even if
+** the other input is NULL.  A NULL and true or two NULLs give
+** a NULL output.
+*/
+/* Opcode: Or P1 P2 P3 * *
+** Synopsis: r[P3]=(r[P1] || r[P2])
+**
+** Take the logical OR of the values in register P1 and P2 and
+** store the answer in register P3.
+**
+** If either P1 or P2 is nonzero (true) then the result is 1 (true)
+** even if the other input is NULL.  A NULL and false or two NULLs
+** give a NULL output.
+*/
+case OP_And:              /* same as TK_AND, in1, in2, out3 */
+case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
+  int v1;    /* Left operand:  0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+  int v2;    /* Right operand: 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
+
+  v1 = sqlite3VdbeBooleanValue(&aMem[pOp->p1], 2);
+  v2 = sqlite3VdbeBooleanValue(&aMem[pOp->p2], 2);
+  if( pOp->opcode==OP_And ){
+    static const unsigned char and_logic[] = { 0, 0, 0, 0, 1, 2, 0, 2, 2 };
+    v1 = and_logic[v1*3+v2];
+  }else{
+    static const unsigned char or_logic[] = { 0, 1, 2, 1, 1, 1, 2, 1, 2 };
+    v1 = or_logic[v1*3+v2];
+  }
+  pOut = &aMem[pOp->p3];
+  if( v1==2 ){
+    MemSetTypeFlag(pOut, MEM_Null);
+  }else{
+    pOut->u.i = v1;
+    MemSetTypeFlag(pOut, MEM_Int);
+  }
+  break;
+}
+
+/* Opcode: IsTrue P1 P2 P3 P4 *
+** Synopsis: r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4
+**
+** This opcode implements the IS TRUE, IS FALSE, IS NOT TRUE, and
+** IS NOT FALSE operators.
+**
+** Interpret the value in register P1 as a boolean value.  Store that
+** boolean (a 0 or 1) in register P2.  Or if the value in register P1 is
+** NULL, then the P3 is stored in register P2.  Invert the answer if P4
+** is 1.
+**
+** The logic is summarized like this:
+**
+** <ul>
+** <li> If P3==0 and P4==0  then  r[P2] := r[P1] IS TRUE
+** <li> If P3==1 and P4==1  then  r[P2] := r[P1] IS FALSE
+** <li> If P3==0 and P4==1  then  r[P2] := r[P1] IS NOT TRUE
+** <li> If P3==1 and P4==0  then  r[P2] := r[P1] IS NOT FALSE
+** </ul>
+*/
+case OP_IsTrue: {               /* in1, out2 */
+  assert( pOp->p4type==P4_INT32 );
+  assert( pOp->p4.i==0 || pOp->p4.i==1 );
+  assert( pOp->p3==0 || pOp->p3==1 );
+  sqlite3VdbeMemSetInt64(&aMem[pOp->p2],
+      sqlite3VdbeBooleanValue(&aMem[pOp->p1], pOp->p3) ^ pOp->p4.i);
+  break;
+}
+
+/* Opcode: Not P1 P2 * * *
+** Synopsis: r[P2]= !r[P1]
+**
+** Interpret the value in register P1 as a boolean value.  Store the
+** boolean complement in register P2.  If the value in register P1 is
+** NULL, then a NULL is stored in P2.
+*/
+case OP_Not: {                /* same as TK_NOT, in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  if( (pIn1->flags & MEM_Null)==0 ){
+    sqlite3VdbeMemSetInt64(pOut, !sqlite3VdbeBooleanValue(pIn1,0));
+  }else{
+    sqlite3VdbeMemSetNull(pOut);
+  }
+  break;
+}
+
+/* Opcode: BitNot P1 P2 * * *
+** Synopsis: r[P2]= ~r[P1]
+**
+** Interpret the content of register P1 as an integer.  Store the
+** ones-complement of the P1 value into register P2.  If P1 holds
+** a NULL then store a NULL in P2.
+*/
+case OP_BitNot: {             /* same as TK_BITNOT, in1, out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  sqlite3VdbeMemSetNull(pOut);
+  if( (pIn1->flags & MEM_Null)==0 ){
+    pOut->flags = MEM_Int;
+    pOut->u.i = ~sqlite3VdbeIntValue(pIn1);
+  }
+  break;
+}
+
+/* Opcode: Once P1 P2 * * *
+**
+** Fall through to the next instruction the first time this opcode is
+** encountered on each invocation of the byte-code program.  Jump to P2
+** on the second and all subsequent encounters during the same invocation.
+**
+** Top-level programs determine first invocation by comparing the P1
+** operand against the P1 operand on the OP_Init opcode at the beginning
+** of the program.  If the P1 values differ, then fall through and make
+** the P1 of this opcode equal to the P1 of OP_Init.  If P1 values are
+** the same then take the jump.
+**
+** For subprograms, there is a bitmask in the VdbeFrame that determines
+** whether or not the jump should be taken.  The bitmask is necessary
+** because the self-altering code trick does not work for recursive
+** triggers.
+*/
+case OP_Once: {             /* jump */
+  u32 iAddr;                /* Address of this instruction */
+  assert( p->aOp[0].opcode==OP_Init );
+  if( p->pFrame ){
+    iAddr = (int)(pOp - p->aOp);
+    if( (p->pFrame->aOnce[iAddr/8] & (1<<(iAddr & 7)))!=0 ){
+      VdbeBranchTaken(1, 2);
+      goto jump_to_p2;
+    }
+    p->pFrame->aOnce[iAddr/8] |= 1<<(iAddr & 7);
+  }else{
+    if( p->aOp[0].p1==pOp->p1 ){
+      VdbeBranchTaken(1, 2);
+      goto jump_to_p2;
+    }
+  }
+  VdbeBranchTaken(0, 2);
+  pOp->p1 = p->aOp[0].p1;
+  break;
+}
+
+/* Opcode: If P1 P2 P3 * *
+**
+** Jump to P2 if the value in register P1 is true.  The value
+** is considered true if it is numeric and non-zero.  If the value
+** in P1 is NULL then take the jump if and only if P3 is non-zero.
+*/
+case OP_If:  {               /* jump, in1 */
+  int c;
+  c = sqlite3VdbeBooleanValue(&aMem[pOp->p1], pOp->p3);
+  VdbeBranchTaken(c!=0, 2);
+  if( c ) goto jump_to_p2;
+  break;
+}
+
+/* Opcode: IfNot P1 P2 P3 * *
+**
+** Jump to P2 if the value in register P1 is False.  The value
+** is considered false if it has a numeric value of zero.  If the value
+** in P1 is NULL then take the jump if and only if P3 is non-zero.
+*/
+case OP_IfNot: {            /* jump, in1 */
+  int c;
+  c = !sqlite3VdbeBooleanValue(&aMem[pOp->p1], !pOp->p3);
+  VdbeBranchTaken(c!=0, 2);
+  if( c ) goto jump_to_p2;
+  break;
+}
+
+/* Opcode: IsNull P1 P2 * * *
+** Synopsis: if r[P1]==NULL goto P2
+**
+** Jump to P2 if the value in register P1 is NULL.
+*/
+case OP_IsNull: {            /* same as TK_ISNULL, jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  VdbeBranchTaken( (pIn1->flags & MEM_Null)!=0, 2);
+  if( (pIn1->flags & MEM_Null)!=0 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: IsType P1 P2 P3 P4 P5
+** Synopsis: if typeof(P1.P3) in P5 goto P2
+**
+** Jump to P2 if the type of a column in a btree is one of the types specified
+** by the P5 bitmask.
+**
+** P1 is normally a cursor on a btree for which the row decode cache is
+** valid through at least column P3.  In other words, there should have been
+** a prior OP_Column for column P3 or greater.  If the cursor is not valid,
+** then this opcode might give spurious results.
+** The the btree row has fewer than P3 columns, then use P4 as the
+** datatype.
+**
+** If P1 is -1, then P3 is a register number and the datatype is taken
+** from the value in that register.
+**
+** P5 is a bitmask of data types.  SQLITE_INTEGER is the least significant
+** (0x01) bit. SQLITE_FLOAT is the 0x02 bit. SQLITE_TEXT is 0x04.
+** SQLITE_BLOB is 0x08.  SQLITE_NULL is 0x10.
+**
+** WARNING: This opcode does not reliably distinguish between NULL and REAL
+** when P1>=0.  If the database contains a NaN value, this opcode will think
+** that the datatype is REAL when it should be NULL.  When P1<0 and the value
+** is already stored in register P3, then this opcode does reliably
+** distinguish between NULL and REAL.  The problem only arises then P1>=0.
+**
+** Take the jump to address P2 if and only if the datatype of the
+** value determined by P1 and P3 corresponds to one of the bits in the
+** P5 bitmask.
+**
+*/
+case OP_IsType: {        /* jump */
+  VdbeCursor *pC;
+  u16 typeMask;
+  u32 serialType;
+
+  assert( pOp->p1>=(-1) && pOp->p1<p->nCursor );
+  assert( pOp->p1>=0 || (pOp->p3>=0 && pOp->p3<=(p->nMem+1 - p->nCursor)) );
+  if( pOp->p1>=0 ){
+    pC = p->apCsr[pOp->p1];
+    assert( pC!=0 );
+    assert( pOp->p3>=0 );
+    if( pOp->p3<pC->nHdrParsed ){
+      serialType = pC->aType[pOp->p3];
+      if( serialType>=12 ){
+        if( serialType&1 ){
+          typeMask = 0x04;   /* SQLITE_TEXT */
+        }else{
+          typeMask = 0x08;   /* SQLITE_BLOB */
+        }
+      }else{
+        static const unsigned char aMask[] = {
+           0x10, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x2,
+           0x01, 0x01, 0x10, 0x10
+        };
+        testcase( serialType==0 );
+        testcase( serialType==1 );
+        testcase( serialType==2 );
+        testcase( serialType==3 );
+        testcase( serialType==4 );
+        testcase( serialType==5 );
+        testcase( serialType==6 );
+        testcase( serialType==7 );
+        testcase( serialType==8 );
+        testcase( serialType==9 );
+        testcase( serialType==10 );
+        testcase( serialType==11 );
+        typeMask = aMask[serialType];
+      }
+    }else{
+      typeMask = 1 << (pOp->p4.i - 1);
+      testcase( typeMask==0x01 );
+      testcase( typeMask==0x02 );
+      testcase( typeMask==0x04 );
+      testcase( typeMask==0x08 );
+      testcase( typeMask==0x10 );
+    }
+  }else{
+    assert( memIsValid(&aMem[pOp->p3]) );
+    typeMask = 1 << (sqlite3_value_type((sqlite3_value*)&aMem[pOp->p3])-1);
+    testcase( typeMask==0x01 );
+    testcase( typeMask==0x02 );
+    testcase( typeMask==0x04 );
+    testcase( typeMask==0x08 );
+    testcase( typeMask==0x10 );
+  }
+  VdbeBranchTaken( (typeMask & pOp->p5)!=0, 2);
+  if( typeMask & pOp->p5 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: ZeroOrNull P1 P2 P3 * *
+** Synopsis: r[P2] = 0 OR NULL
+**
+** If both registers P1 and P3 are NOT NULL, then store a zero in
+** register P2.  If either registers P1 or P3 are NULL then put
+** a NULL in register P2.
+*/
+case OP_ZeroOrNull: {            /* in1, in2, out2, in3 */
+  if( (aMem[pOp->p1].flags & MEM_Null)!=0
+   || (aMem[pOp->p3].flags & MEM_Null)!=0
+  ){
+    sqlite3VdbeMemSetNull(aMem + pOp->p2);
+  }else{
+    sqlite3VdbeMemSetInt64(aMem + pOp->p2, 0);
+  }
+  break;
+}
+
+/* Opcode: NotNull P1 P2 * * *
+** Synopsis: if r[P1]!=NULL goto P2
+**
+** Jump to P2 if the value in register P1 is not NULL.
+*/
+case OP_NotNull: {            /* same as TK_NOTNULL, jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  VdbeBranchTaken( (pIn1->flags & MEM_Null)==0, 2);
+  if( (pIn1->flags & MEM_Null)==0 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: IfNullRow P1 P2 P3 * *
+** Synopsis: if P1.nullRow then r[P3]=NULL, goto P2
+**
+** Check the cursor P1 to see if it is currently pointing at a NULL row.
+** If it is, then set register P3 to NULL and jump immediately to P2.
+** If P1 is not on a NULL row, then fall through without making any
+** changes.
+**
+** If P1 is not an open cursor, then this opcode is a no-op.
+*/
+case OP_IfNullRow: {         /* jump */
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  if( pC && pC->nullRow ){
+    sqlite3VdbeMemSetNull(aMem + pOp->p3);
+    goto jump_to_p2;
+  }
+  break;
+}
+
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+/* Opcode: Offset P1 P2 P3 * *
+** Synopsis: r[P3] = sqlite_offset(P1)
+**
+** Store in register r[P3] the byte offset into the database file that is the
+** start of the payload for the record at which that cursor P1 is currently
+** pointing.
+**
+** P2 is the column number for the argument to the sqlite_offset() function.
+** This opcode does not use P2 itself, but the P2 value is used by the
+** code generator.  The P1, P2, and P3 operands to this opcode are the
+** same as for OP_Column.
+**
+** This opcode is only available if SQLite is compiled with the
+** -DSQLITE_ENABLE_OFFSET_SQL_FUNC option.
+*/
+case OP_Offset: {          /* out3 */
+  VdbeCursor *pC;    /* The VDBE cursor */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  pOut = &p->aMem[pOp->p3];
+  if( pC==0 || pC->eCurType!=CURTYPE_BTREE ){
+    sqlite3VdbeMemSetNull(pOut);
+  }else{
+    if( pC->deferredMoveto ){
+      rc = sqlite3VdbeFinishMoveto(pC);
+      if( rc ) goto abort_due_to_error;
+    }
+    if( sqlite3BtreeEof(pC->uc.pCursor) ){
+      sqlite3VdbeMemSetNull(pOut);
+    }else{
+      sqlite3VdbeMemSetInt64(pOut, sqlite3BtreeOffset(pC->uc.pCursor));
+    }
+  }
+  break;
+}
+#endif /* SQLITE_ENABLE_OFFSET_SQL_FUNC */
+
+/* Opcode: Column P1 P2 P3 P4 P5
+** Synopsis: r[P3]=PX cursor P1 column P2
+**
+** Interpret the data that cursor P1 points to as a structure built using
+** the MakeRecord instruction.  (See the MakeRecord opcode for additional
+** information about the format of the data.)  Extract the P2-th column
+** from this record.  If there are less than (P2+1)
+** values in the record, extract a NULL.
+**
+** The value extracted is stored in register P3.
+**
+** If the record contains fewer than P2 fields, then extract a NULL.  Or,
+** if the P4 argument is a P4_MEM use the value of the P4 argument as
+** the result.
+**
+** If the OPFLAG_LENGTHARG bit is set in P5 then the result is guaranteed
+** to only be used by the length() function or the equivalent.  The content
+** of large blobs is not loaded, thus saving CPU cycles.  If the
+** OPFLAG_TYPEOFARG bit is set then the result will only be used by the
+** typeof() function or the IS NULL or IS NOT NULL operators or the
+** equivalent.  In this case, all content loading can be omitted.
+*/
+case OP_Column: {            /* ncycle */
+  u32 p2;            /* column number to retrieve */
+  VdbeCursor *pC;    /* The VDBE cursor */
+  BtCursor *pCrsr;   /* The B-Tree cursor corresponding to pC */
+  u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
+  int len;           /* The length of the serialized data for the column */
+  int i;             /* Loop counter */
+  Mem *pDest;        /* Where to write the extracted value */
+  Mem sMem;          /* For storing the record being decoded */
+  const u8 *zData;   /* Part of the record being decoded */
+  const u8 *zHdr;    /* Next unparsed byte of the header */
+  const u8 *zEndHdr; /* Pointer to first byte after the header */
+  u64 offset64;      /* 64-bit offset */
+  u32 t;             /* A type code from the record header */
+  Mem *pReg;         /* PseudoTable input register */
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  pC = p->apCsr[pOp->p1];
+  p2 = (u32)pOp->p2;
+
+op_column_restart:
+  assert( pC!=0 );
+  assert( p2<(u32)pC->nField
+       || (pC->eCurType==CURTYPE_PSEUDO && pC->seekResult==0) );
+  aOffset = pC->aOffset;
+  assert( aOffset==pC->aType+pC->nField );
+  assert( pC->eCurType!=CURTYPE_VTAB );
+  assert( pC->eCurType!=CURTYPE_PSEUDO || pC->nullRow );
+  assert( pC->eCurType!=CURTYPE_SORTER );
+
+  if( pC->cacheStatus!=p->cacheCtr ){                /*OPTIMIZATION-IF-FALSE*/
+    if( pC->nullRow ){
+      if( pC->eCurType==CURTYPE_PSEUDO && pC->seekResult>0 ){
+        /* For the special case of as pseudo-cursor, the seekResult field
+        ** identifies the register that holds the record */
+        pReg = &aMem[pC->seekResult];
+        assert( pReg->flags & MEM_Blob );
+        assert( memIsValid(pReg) );
+        pC->payloadSize = pC->szRow = pReg->n;
+        pC->aRow = (u8*)pReg->z;
+      }else{
+        pDest = &aMem[pOp->p3];
+        memAboutToChange(p, pDest);
+        sqlite3VdbeMemSetNull(pDest);
+        goto op_column_out;
+      }
+    }else{
+      pCrsr = pC->uc.pCursor;
+      if( pC->deferredMoveto ){
+        u32 iMap;
+        assert( !pC->isEphemeral );
+        if( pC->ub.aAltMap && (iMap = pC->ub.aAltMap[1+p2])>0  ){
+          pC = pC->pAltCursor;
+          p2 = iMap - 1;
+          goto op_column_restart;
+        }
+        rc = sqlite3VdbeFinishMoveto(pC);
+        if( rc ) goto abort_due_to_error;
+      }else if( sqlite3BtreeCursorHasMoved(pCrsr) ){
+        rc = sqlite3VdbeHandleMovedCursor(pC);
+        if( rc ) goto abort_due_to_error;
+        goto op_column_restart;
+      }
+      assert( pC->eCurType==CURTYPE_BTREE );
+      assert( pCrsr );
+      assert( sqlite3BtreeCursorIsValid(pCrsr) );
+      pC->payloadSize = sqlite3BtreePayloadSize(pCrsr);
+      pC->aRow = sqlite3BtreePayloadFetch(pCrsr, &pC->szRow);
+      assert( pC->szRow<=pC->payloadSize );
+      assert( pC->szRow<=65536 );  /* Maximum page size is 64KiB */
+    }
+    pC->cacheStatus = p->cacheCtr;
+    if( (aOffset[0] = pC->aRow[0])<0x80 ){
+      pC->iHdrOffset = 1;
+    }else{
+      pC->iHdrOffset = sqlite3GetVarint32(pC->aRow, aOffset);
+    }
+    pC->nHdrParsed = 0;
+
+    if( pC->szRow<aOffset[0] ){      /*OPTIMIZATION-IF-FALSE*/
+      /* pC->aRow does not have to hold the entire row, but it does at least
+      ** need to cover the header of the record.  If pC->aRow does not contain
+      ** the complete header, then set it to zero, forcing the header to be
+      ** dynamically allocated. */
+      pC->aRow = 0;
+      pC->szRow = 0;
+
+      /* Make sure a corrupt database has not given us an oversize header.
+      ** Do this now to avoid an oversize memory allocation.
+      **
+      ** Type entries can be between 1 and 5 bytes each.  But 4 and 5 byte
+      ** types use so much data space that there can only be 4096 and 32 of
+      ** them, respectively.  So the maximum header length results from a
+      ** 3-byte type for each of the maximum of 32768 columns plus three
+      ** extra bytes for the header length itself.  32768*3 + 3 = 98307.
+      */
+      if( aOffset[0] > 98307 || aOffset[0] > pC->payloadSize ){
+        goto op_column_corrupt;
+      }
+    }else{
+      /* This is an optimization.  By skipping over the first few tests
+      ** (ex: pC->nHdrParsed<=p2) in the next section, we achieve a
+      ** measurable performance gain.
+      **
+      ** This branch is taken even if aOffset[0]==0.  Such a record is never
+      ** generated by SQLite, and could be considered corruption, but we
+      ** accept it for historical reasons.  When aOffset[0]==0, the code this
+      ** branch jumps to reads past the end of the record, but never more
+      ** than a few bytes.  Even if the record occurs at the end of the page
+      ** content area, the "page header" comes after the page content and so
+      ** this overread is harmless.  Similar overreads can occur for a corrupt
+      ** database file.
+      */
+      zData = pC->aRow;
+      assert( pC->nHdrParsed<=p2 );         /* Conditional skipped */
+      testcase( aOffset[0]==0 );
+      goto op_column_read_header;
+    }
+  }else if( sqlite3BtreeCursorHasMoved(pC->uc.pCursor) ){
+    rc = sqlite3VdbeHandleMovedCursor(pC);
+    if( rc ) goto abort_due_to_error;
+    goto op_column_restart;
+  }
+
+  /* Make sure at least the first p2+1 entries of the header have been
+  ** parsed and valid information is in aOffset[] and pC->aType[].
+  */
+  if( pC->nHdrParsed<=p2 ){
+    /* If there is more header available for parsing in the record, try
+    ** to extract additional fields up through the p2+1-th field
+    */
+    if( pC->iHdrOffset<aOffset[0] ){
+      /* Make sure zData points to enough of the record to cover the header. */
+      if( pC->aRow==0 ){
+        memset(&sMem, 0, sizeof(sMem));
+        rc = sqlite3VdbeMemFromBtreeZeroOffset(pC->uc.pCursor,aOffset[0],&sMem);
+        if( rc!=SQLITE_OK ) goto abort_due_to_error;
+        zData = (u8*)sMem.z;
+      }else{
+        zData = pC->aRow;
+      }
+
+      /* Fill in pC->aType[i] and aOffset[i] values through the p2-th field. */
+    op_column_read_header:
+      i = pC->nHdrParsed;
+      offset64 = aOffset[i];
+      zHdr = zData + pC->iHdrOffset;
+      zEndHdr = zData + aOffset[0];
+      testcase( zHdr>=zEndHdr );
+      do{
+        if( (pC->aType[i] = t = zHdr[0])<0x80 ){
+          zHdr++;
+          offset64 += sqlite3VdbeOneByteSerialTypeLen(t);
+        }else{
+          zHdr += sqlite3GetVarint32(zHdr, &t);
+          pC->aType[i] = t;
+          offset64 += sqlite3VdbeSerialTypeLen(t);
+        }
+        aOffset[++i] = (u32)(offset64 & 0xffffffff);
+      }while( (u32)i<=p2 && zHdr<zEndHdr );
+
+      /* The record is corrupt if any of the following are true:
+      ** (1) the bytes of the header extend past the declared header size
+      ** (2) the entire header was used but not all data was used
+      ** (3) the end of the data extends beyond the end of the record.
+      */
+      if( (zHdr>=zEndHdr && (zHdr>zEndHdr || offset64!=pC->payloadSize))
+       || (offset64 > pC->payloadSize)
+      ){
+        if( aOffset[0]==0 ){
+          i = 0;
+          zHdr = zEndHdr;
+        }else{
+          if( pC->aRow==0 ) sqlite3VdbeMemRelease(&sMem);
+          goto op_column_corrupt;
+        }
+      }
+
+      pC->nHdrParsed = i;
+      pC->iHdrOffset = (u32)(zHdr - zData);
+      if( pC->aRow==0 ) sqlite3VdbeMemRelease(&sMem);
+    }else{
+      t = 0;
+    }
+
+    /* If after trying to extract new entries from the header, nHdrParsed is
+    ** still not up to p2, that means that the record has fewer than p2
+    ** columns.  So the result will be either the default value or a NULL.
+    */
+    if( pC->nHdrParsed<=p2 ){
+      pDest = &aMem[pOp->p3];
+      memAboutToChange(p, pDest);
+      if( pOp->p4type==P4_MEM ){
+        sqlite3VdbeMemShallowCopy(pDest, pOp->p4.pMem, MEM_Static);
+      }else{
+        sqlite3VdbeMemSetNull(pDest);
+      }
+      goto op_column_out;
+    }
+  }else{
+    t = pC->aType[p2];
+  }
+
+  /* Extract the content for the p2+1-th column.  Control can only
+  ** reach this point if aOffset[p2], aOffset[p2+1], and pC->aType[p2] are
+  ** all valid.
+  */
+  assert( p2<pC->nHdrParsed );
+  assert( rc==SQLITE_OK );
+  pDest = &aMem[pOp->p3];
+  memAboutToChange(p, pDest);
+  assert( sqlite3VdbeCheckMemInvariants(pDest) );
+  if( VdbeMemDynamic(pDest) ){
+    sqlite3VdbeMemSetNull(pDest);
+  }
+  assert( t==pC->aType[p2] );
+  if( pC->szRow>=aOffset[p2+1] ){
+    /* This is the common case where the desired content fits on the original
+    ** page - where the content is not on an overflow page */
+    zData = pC->aRow + aOffset[p2];
+    if( t<12 ){
+      sqlite3VdbeSerialGet(zData, t, pDest);
+    }else{
+      /* If the column value is a string, we need a persistent value, not
+      ** a MEM_Ephem value.  This branch is a fast short-cut that is equivalent
+      ** to calling sqlite3VdbeSerialGet() and sqlite3VdbeDeephemeralize().
+      */
+      static const u16 aFlag[] = { MEM_Blob, MEM_Str|MEM_Term };
+      pDest->n = len = (t-12)/2;
+      pDest->enc = encoding;
+      if( pDest->szMalloc < len+2 ){
+        if( len>db->aLimit[SQLITE_LIMIT_LENGTH] ) goto too_big;
+        pDest->flags = MEM_Null;
+        if( sqlite3VdbeMemGrow(pDest, len+2, 0) ) goto no_mem;
+      }else{
+        pDest->z = pDest->zMalloc;
+      }
+      memcpy(pDest->z, zData, len);
+      pDest->z[len] = 0;
+      pDest->z[len+1] = 0;
+      pDest->flags = aFlag[t&1];
+    }
+  }else{
+    u8 p5;
+    pDest->enc = encoding;
+    assert( pDest->db==db );
+    /* This branch happens only when content is on overflow pages */
+    if( ((p5 = (pOp->p5 & OPFLAG_BYTELENARG))!=0
+          && (p5==OPFLAG_TYPEOFARG
+              || (t>=12 && ((t&1)==0 || p5==OPFLAG_BYTELENARG))
+             )
+        )
+     || sqlite3VdbeSerialTypeLen(t)==0
+    ){
+      /* Content is irrelevant for
+      **    1. the typeof() function,
+      **    2. the length(X) function if X is a blob, and
+      **    3. if the content length is zero.
+      ** So we might as well use bogus content rather than reading
+      ** content from disk.
+      **
+      ** Although sqlite3VdbeSerialGet() may read at most 8 bytes from the
+      ** buffer passed to it, debugging function VdbeMemPrettyPrint() may
+      ** read more.  Use the global constant sqlite3CtypeMap[] as the array,
+      ** as that array is 256 bytes long (plenty for VdbeMemPrettyPrint())
+      ** and it begins with a bunch of zeros.
+      */
+      sqlite3VdbeSerialGet((u8*)sqlite3CtypeMap, t, pDest);
+    }else{
+      rc = vdbeColumnFromOverflow(pC, p2, t, aOffset[p2],
+                p->cacheCtr, colCacheCtr, pDest);
+      if( rc ){
+        if( rc==SQLITE_NOMEM ) goto no_mem;
+        if( rc==SQLITE_TOOBIG ) goto too_big;
+        goto abort_due_to_error;
+      }
+    }
+  }
+
+op_column_out:
+  UPDATE_MAX_BLOBSIZE(pDest);
+  REGISTER_TRACE(pOp->p3, pDest);
+  break;
+
+op_column_corrupt:
+  if( aOp[0].p3>0 ){
+    pOp = &aOp[aOp[0].p3-1];
+    break;
+  }else{
+    rc = SQLITE_CORRUPT_BKPT;
+    goto abort_due_to_error;
+  }
+}
+
+/* Opcode: TypeCheck P1 P2 P3 P4 *
+** Synopsis: typecheck(r[P1@P2])
+**
+** Apply affinities to the range of P2 registers beginning with P1.
+** Take the affinities from the Table object in P4.  If any value
+** cannot be coerced into the correct type, then raise an error.
+**
+** This opcode is similar to OP_Affinity except that this opcode
+** forces the register type to the Table column type.  This is used
+** to implement "strict affinity".
+**
+** GENERATED ALWAYS AS ... STATIC columns are only checked if P3
+** is zero.  When P3 is non-zero, no type checking occurs for
+** static generated columns.  Virtual columns are computed at query time
+** and so they are never checked.
+**
+** Preconditions:
+**
+** <ul>
+** <li> P2 should be the number of non-virtual columns in the
+**      table of P4.
+** <li> Table P4 should be a STRICT table.
+** </ul>
+**
+** If any precondition is false, an assertion fault occurs.
+*/
+case OP_TypeCheck: {
+  Table *pTab;
+  Column *aCol;
+  int i;
+
+  assert( pOp->p4type==P4_TABLE );
+  pTab = pOp->p4.pTab;
+  assert( pTab->tabFlags & TF_Strict );
+  assert( pTab->nNVCol==pOp->p2 );
+  aCol = pTab->aCol;
+  pIn1 = &aMem[pOp->p1];
+  for(i=0; i<pTab->nCol; i++){
+    if( aCol[i].colFlags & COLFLAG_GENERATED ){
+      if( aCol[i].colFlags & COLFLAG_VIRTUAL ) continue;
+      if( pOp->p3 ){ pIn1++; continue; }
+    }
+    assert( pIn1 < &aMem[pOp->p1+pOp->p2] );
+    applyAffinity(pIn1, aCol[i].affinity, encoding);
+    if( (pIn1->flags & MEM_Null)==0 ){
+      switch( aCol[i].eCType ){
+        case COLTYPE_BLOB: {
+          if( (pIn1->flags & MEM_Blob)==0 ) goto vdbe_type_error;
+          break;
+        }
+        case COLTYPE_INTEGER:
+        case COLTYPE_INT: {
+          if( (pIn1->flags & MEM_Int)==0 ) goto vdbe_type_error;
+          break;
+        }
+        case COLTYPE_TEXT: {
+          if( (pIn1->flags & MEM_Str)==0 ) goto vdbe_type_error;
+          break;
+        }
+        case COLTYPE_REAL: {
+          testcase( (pIn1->flags & (MEM_Real|MEM_IntReal))==MEM_Real );
+          assert( (pIn1->flags & MEM_IntReal)==0 );
+          if( pIn1->flags & MEM_Int ){
+            /* When applying REAL affinity, if the result is still an MEM_Int
+            ** that will fit in 6 bytes, then change the type to MEM_IntReal
+            ** so that we keep the high-resolution integer value but know that
+            ** the type really wants to be REAL. */
+            testcase( pIn1->u.i==140737488355328LL );
+            testcase( pIn1->u.i==140737488355327LL );
+            testcase( pIn1->u.i==-140737488355328LL );
+            testcase( pIn1->u.i==-140737488355329LL );
+            if( pIn1->u.i<=140737488355327LL && pIn1->u.i>=-140737488355328LL){
+              pIn1->flags |= MEM_IntReal;
+              pIn1->flags &= ~MEM_Int;
+            }else{
+              pIn1->u.r = (double)pIn1->u.i;
+              pIn1->flags |= MEM_Real;
+              pIn1->flags &= ~MEM_Int;
+            }
+          }else if( (pIn1->flags & (MEM_Real|MEM_IntReal))==0 ){
+            goto vdbe_type_error;
+          }
+          break;
+        }
+        default: {
+          /* COLTYPE_ANY.  Accept anything. */
+          break;
+        }
+      }
+    }
+    REGISTER_TRACE((int)(pIn1-aMem), pIn1);
+    pIn1++;
+  }
+  assert( pIn1 == &aMem[pOp->p1+pOp->p2] );
+  break;
+
+vdbe_type_error:
+  sqlite3VdbeError(p, "cannot store %s value in %s column %s.%s",
+     vdbeMemTypeName(pIn1), sqlite3StdType[aCol[i].eCType-1],
+     pTab->zName, aCol[i].zCnName);
+  rc = SQLITE_CONSTRAINT_DATATYPE;
+  goto abort_due_to_error;
+}
+
+/* Opcode: Affinity P1 P2 * P4 *
+** Synopsis: affinity(r[P1@P2])
+**
+** Apply affinities to a range of P2 registers starting with P1.
+**
+** P4 is a string that is P2 characters long. The N-th character of the
+** string indicates the column affinity that should be used for the N-th
+** memory cell in the range.
+*/
+case OP_Affinity: {
+  const char *zAffinity;   /* The affinity to be applied */
+
+  zAffinity = pOp->p4.z;
+  assert( zAffinity!=0 );
+  assert( pOp->p2>0 );
+  assert( zAffinity[pOp->p2]==0 );
+  pIn1 = &aMem[pOp->p1];
+  while( 1 /*exit-by-break*/ ){
+    assert( pIn1 <= &p->aMem[(p->nMem+1 - p->nCursor)] );
+    assert( zAffinity[0]==SQLITE_AFF_NONE || memIsValid(pIn1) );
+    applyAffinity(pIn1, zAffinity[0], encoding);
+    if( zAffinity[0]==SQLITE_AFF_REAL && (pIn1->flags & MEM_Int)!=0 ){
+      /* When applying REAL affinity, if the result is still an MEM_Int
+      ** that will fit in 6 bytes, then change the type to MEM_IntReal
+      ** so that we keep the high-resolution integer value but know that
+      ** the type really wants to be REAL. */
+      testcase( pIn1->u.i==140737488355328LL );
+      testcase( pIn1->u.i==140737488355327LL );
+      testcase( pIn1->u.i==-140737488355328LL );
+      testcase( pIn1->u.i==-140737488355329LL );
+      if( pIn1->u.i<=140737488355327LL && pIn1->u.i>=-140737488355328LL ){
+        pIn1->flags |= MEM_IntReal;
+        pIn1->flags &= ~MEM_Int;
+      }else{
+        pIn1->u.r = (double)pIn1->u.i;
+        pIn1->flags |= MEM_Real;
+        pIn1->flags &= ~(MEM_Int|MEM_Str);
+      }
+    }
+    REGISTER_TRACE((int)(pIn1-aMem), pIn1);
+    zAffinity++;
+    if( zAffinity[0]==0 ) break;
+    pIn1++;
+  }
+  break;
+}
+
+/* Opcode: MakeRecord P1 P2 P3 P4 *
+** Synopsis: r[P3]=mkrec(r[P1@P2])
+**
+** Convert P2 registers beginning with P1 into the [record format]
+** use as a data record in a database table or as a key
+** in an index.  The OP_Column opcode can decode the record later.
+**
+** P4 may be a string that is P2 characters long.  The N-th character of the
+** string indicates the column affinity that should be used for the N-th
+** field of the index key.
+**
+** The mapping from character to affinity is given by the SQLITE_AFF_
+** macros defined in sqliteInt.h.
+**
+** If P4 is NULL then all index fields have the affinity BLOB.
+**
+** The meaning of P5 depends on whether or not the SQLITE_ENABLE_NULL_TRIM
+** compile-time option is enabled:
+**
+**   * If SQLITE_ENABLE_NULL_TRIM is enabled, then the P5 is the index
+**     of the right-most table that can be null-trimmed.
+**
+**   * If SQLITE_ENABLE_NULL_TRIM is omitted, then P5 has the value
+**     OPFLAG_NOCHNG_MAGIC if the OP_MakeRecord opcode is allowed to
+**     accept no-change records with serial_type 10.  This value is
+**     only used inside an assert() and does not affect the end result.
+*/
+case OP_MakeRecord: {
+  Mem *pRec;             /* The new record */
+  u64 nData;             /* Number of bytes of data space */
+  int nHdr;              /* Number of bytes of header space */
+  i64 nByte;             /* Data space required for this record */
+  i64 nZero;             /* Number of zero bytes at the end of the record */
+  int nVarint;           /* Number of bytes in a varint */
+  u32 serial_type;       /* Type field */
+  Mem *pData0;           /* First field to be combined into the record */
+  Mem *pLast;            /* Last field of the record */
+  int nField;            /* Number of fields in the record */
+  char *zAffinity;       /* The affinity string for the record */
+  u32 len;               /* Length of a field */
+  u8 *zHdr;              /* Where to write next byte of the header */
+  u8 *zPayload;          /* Where to write next byte of the payload */
+
+  /* Assuming the record contains N fields, the record format looks
+  ** like this:
+  **
+  ** ------------------------------------------------------------------------
+  ** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 |
+  ** ------------------------------------------------------------------------
+  **
+  ** Data(0) is taken from register P1.  Data(1) comes from register P1+1
+  ** and so forth.
+  **
+  ** Each type field is a varint representing the serial type of the
+  ** corresponding data element (see sqlite3VdbeSerialType()). The
+  ** hdr-size field is also a varint which is the offset from the beginning
+  ** of the record to data0.
+  */
+  nData = 0;         /* Number of bytes of data space */
+  nHdr = 0;          /* Number of bytes of header space */
+  nZero = 0;         /* Number of zero bytes at the end of the record */
+  nField = pOp->p1;
+  zAffinity = pOp->p4.z;
+  assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=(p->nMem+1 - p->nCursor)+1 );
+  pData0 = &aMem[nField];
+  nField = pOp->p2;
+  pLast = &pData0[nField-1];
+
+  /* Identify the output register */
+  assert( pOp->p3<pOp->p1 || pOp->p3>=pOp->p1+pOp->p2 );
+  pOut = &aMem[pOp->p3];
+  memAboutToChange(p, pOut);
+
+  /* Apply the requested affinity to all inputs
+  */
+  assert( pData0<=pLast );
+  if( zAffinity ){
+    pRec = pData0;
+    do{
+      applyAffinity(pRec, zAffinity[0], encoding);
+      if( zAffinity[0]==SQLITE_AFF_REAL && (pRec->flags & MEM_Int) ){
+        pRec->flags |= MEM_IntReal;
+        pRec->flags &= ~(MEM_Int);
+      }
+      REGISTER_TRACE((int)(pRec-aMem), pRec);
+      zAffinity++;
+      pRec++;
+      assert( zAffinity[0]==0 || pRec<=pLast );
+    }while( zAffinity[0] );
+  }
+
+#ifdef SQLITE_ENABLE_NULL_TRIM
+  /* NULLs can be safely trimmed from the end of the record, as long as
+  ** as the schema format is 2 or more and none of the omitted columns
+  ** have a non-NULL default value.  Also, the record must be left with
+  ** at least one field.  If P5>0 then it will be one more than the
+  ** index of the right-most column with a non-NULL default value */
+  if( pOp->p5 ){
+    while( (pLast->flags & MEM_Null)!=0 && nField>pOp->p5 ){
+      pLast--;
+      nField--;
+    }
+  }
+#endif
+
+  /* Loop through the elements that will make up the record to figure
+  ** out how much space is required for the new record.  After this loop,
+  ** the Mem.uTemp field of each term should hold the serial-type that will
+  ** be used for that term in the generated record:
+  **
+  **   Mem.uTemp value    type
+  **   ---------------    ---------------
+  **      0               NULL
+  **      1               1-byte signed integer
+  **      2               2-byte signed integer
+  **      3               3-byte signed integer
+  **      4               4-byte signed integer
+  **      5               6-byte signed integer
+  **      6               8-byte signed integer
+  **      7               IEEE float
+  **      8               Integer constant 0
+  **      9               Integer constant 1
+  **     10,11            reserved for expansion
+  **    N>=12 and even    BLOB
+  **    N>=13 and odd     text
+  **
+  ** The following additional values are computed:
+  **     nHdr        Number of bytes needed for the record header
+  **     nData       Number of bytes of data space needed for the record
+  **     nZero       Zero bytes at the end of the record
+  */
+  pRec = pLast;
+  do{
+    assert( memIsValid(pRec) );
+    if( pRec->flags & MEM_Null ){
+      if( pRec->flags & MEM_Zero ){
+        /* Values with MEM_Null and MEM_Zero are created by xColumn virtual
+        ** table methods that never invoke sqlite3_result_xxxxx() while
+        ** computing an unchanging column value in an UPDATE statement.
+        ** Give such values a special internal-use-only serial-type of 10
+        ** so that they can be passed through to xUpdate and have
+        ** a true sqlite3_value_nochange(). */
+#ifndef SQLITE_ENABLE_NULL_TRIM
+        assert( pOp->p5==OPFLAG_NOCHNG_MAGIC || CORRUPT_DB );
+#endif
+        pRec->uTemp = 10;
+      }else{
+        pRec->uTemp = 0;
+      }
+      nHdr++;
+    }else if( pRec->flags & (MEM_Int|MEM_IntReal) ){
+      /* Figure out whether to use 1, 2, 4, 6 or 8 bytes. */
+      i64 i = pRec->u.i;
+      u64 uu;
+      testcase( pRec->flags & MEM_Int );
+      testcase( pRec->flags & MEM_IntReal );
+      if( i<0 ){
+        uu = ~i;
+      }else{
+        uu = i;
+      }
+      nHdr++;
+      testcase( uu==127 );               testcase( uu==128 );
+      testcase( uu==32767 );             testcase( uu==32768 );
+      testcase( uu==8388607 );           testcase( uu==8388608 );
+      testcase( uu==2147483647 );        testcase( uu==2147483648LL );
+      testcase( uu==140737488355327LL ); testcase( uu==140737488355328LL );
+      if( uu<=127 ){
+        if( (i&1)==i && p->minWriteFileFormat>=4 ){
+          pRec->uTemp = 8+(u32)uu;
+        }else{
+          nData++;
+          pRec->uTemp = 1;
+        }
+      }else if( uu<=32767 ){
+        nData += 2;
+        pRec->uTemp = 2;
+      }else if( uu<=8388607 ){
+        nData += 3;
+        pRec->uTemp = 3;
+      }else if( uu<=2147483647 ){
+        nData += 4;
+        pRec->uTemp = 4;
+      }else if( uu<=140737488355327LL ){
+        nData += 6;
+        pRec->uTemp = 5;
+      }else{
+        nData += 8;
+        if( pRec->flags & MEM_IntReal ){
+          /* If the value is IntReal and is going to take up 8 bytes to store
+          ** as an integer, then we might as well make it an 8-byte floating
+          ** point value */
+          pRec->u.r = (double)pRec->u.i;
+          pRec->flags &= ~MEM_IntReal;
+          pRec->flags |= MEM_Real;
+          pRec->uTemp = 7;
+        }else{
+          pRec->uTemp = 6;
+        }
+      }
+    }else if( pRec->flags & MEM_Real ){
+      nHdr++;
+      nData += 8;
+      pRec->uTemp = 7;
+    }else{
+      assert( db->mallocFailed || pRec->flags&(MEM_Str|MEM_Blob) );
+      assert( pRec->n>=0 );
+      len = (u32)pRec->n;
+      serial_type = (len*2) + 12 + ((pRec->flags & MEM_Str)!=0);
+      if( pRec->flags & MEM_Zero ){
+        serial_type += pRec->u.nZero*2;
+        if( nData ){
+          if( sqlite3VdbeMemExpandBlob(pRec) ) goto no_mem;
+          len += pRec->u.nZero;
+        }else{
+          nZero += pRec->u.nZero;
+        }
+      }
+      nData += len;
+      nHdr += sqlite3VarintLen(serial_type);
+      pRec->uTemp = serial_type;
+    }
+    if( pRec==pData0 ) break;
+    pRec--;
+  }while(1);
+
+  /* EVIDENCE-OF: R-22564-11647 The header begins with a single varint
+  ** which determines the total number of bytes in the header. The varint
+  ** value is the size of the header in bytes including the size varint
+  ** itself. */
+  testcase( nHdr==126 );
+  testcase( nHdr==127 );
+  if( nHdr<=126 ){
+    /* The common case */
+    nHdr += 1;
+  }else{
+    /* Rare case of a really large header */
+    nVarint = sqlite3VarintLen(nHdr);
+    nHdr += nVarint;
+    if( nVarint<sqlite3VarintLen(nHdr) ) nHdr++;
+  }
+  nByte = nHdr+nData;
+
+  /* Make sure the output register has a buffer large enough to store
+  ** the new record. The output register (pOp->p3) is not allowed to
+  ** be one of the input registers (because the following call to
+  ** sqlite3VdbeMemClearAndResize() could clobber the value before it is used).
+  */
+  if( nByte+nZero<=pOut->szMalloc ){
+    /* The output register is already large enough to hold the record.
+    ** No error checks or buffer enlargement is required */
+    pOut->z = pOut->zMalloc;
+  }else{
+    /* Need to make sure that the output is not too big and then enlarge
+    ** the output register to hold the full result */
+    if( nByte+nZero>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+      goto too_big;
+    }
+    if( sqlite3VdbeMemClearAndResize(pOut, (int)nByte) ){
+      goto no_mem;
+    }
+  }
+  pOut->n = (int)nByte;
+  pOut->flags = MEM_Blob;
+  if( nZero ){
+    pOut->u.nZero = nZero;
+    pOut->flags |= MEM_Zero;
+  }
+  UPDATE_MAX_BLOBSIZE(pOut);
+  zHdr = (u8 *)pOut->z;
+  zPayload = zHdr + nHdr;
+
+  /* Write the record */
+  if( nHdr<0x80 ){
+    *(zHdr++) = nHdr;
+  }else{
+    zHdr += sqlite3PutVarint(zHdr,nHdr);
+  }
+  assert( pData0<=pLast );
+  pRec = pData0;
+  while( 1 /*exit-by-break*/ ){
+    serial_type = pRec->uTemp;
+    /* EVIDENCE-OF: R-06529-47362 Following the size varint are one or more
+    ** additional varints, one per column.
+    ** EVIDENCE-OF: R-64536-51728 The values for each column in the record
+    ** immediately follow the header. */
+    if( serial_type<=7 ){
+      *(zHdr++) = serial_type;
+      if( serial_type==0 ){
+        /* NULL value.  No change in zPayload */
+      }else{
+        u64 v;
+        if( serial_type==7 ){
+          assert( sizeof(v)==sizeof(pRec->u.r) );
+          memcpy(&v, &pRec->u.r, sizeof(v));
+          swapMixedEndianFloat(v);
+        }else{
+          v = pRec->u.i;
+        }
+        len = sqlite3SmallTypeSizes[serial_type];
+        assert( len>=1 && len<=8 && len!=5 && len!=7 );
+        switch( len ){
+          default: zPayload[7] = (u8)(v&0xff); v >>= 8;
+                   zPayload[6] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 6:  zPayload[5] = (u8)(v&0xff); v >>= 8;
+                   zPayload[4] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 4:  zPayload[3] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 3:  zPayload[2] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 2:  zPayload[1] = (u8)(v&0xff); v >>= 8;
+                   /* no break */ deliberate_fall_through
+          case 1:  zPayload[0] = (u8)(v&0xff);
+        }
+        zPayload += len;
+      }
+    }else if( serial_type<0x80 ){
+      *(zHdr++) = serial_type;
+      if( serial_type>=14 && pRec->n>0 ){
+        assert( pRec->z!=0 );
+        memcpy(zPayload, pRec->z, pRec->n);
+        zPayload += pRec->n;
+      }
+    }else{
+      zHdr += sqlite3PutVarint(zHdr, serial_type);
+      if( pRec->n ){
+        assert( pRec->z!=0 );
+        assert( pRec->z!=(const char*)sqlite3CtypeMap );
+        memcpy(zPayload, pRec->z, pRec->n);
+        zPayload += pRec->n;
+      }
+    }
+    if( pRec==pLast ) break;
+    pRec++;
+  }
+  assert( nHdr==(int)(zHdr - (u8*)pOut->z) );
+  assert( nByte==(int)(zPayload - (u8*)pOut->z) );
+
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  REGISTER_TRACE(pOp->p3, pOut);
+  break;
+}
+
+/* Opcode: Count P1 P2 P3 * *
+** Synopsis: r[P2]=count()
+**
+** Store the number of entries (an integer value) in the table or index
+** opened by cursor P1 in register P2.
+**
+** If P3==0, then an exact count is obtained, which involves visiting
+** every btree page of the table.  But if P3 is non-zero, an estimate
+** is returned based on the current cursor position.
+*/
+case OP_Count: {         /* out2 */
+  i64 nEntry;
+  BtCursor *pCrsr;
+
+  assert( p->apCsr[pOp->p1]->eCurType==CURTYPE_BTREE );
+  pCrsr = p->apCsr[pOp->p1]->uc.pCursor;
+  assert( pCrsr );
+  if( pOp->p3 ){
+    nEntry = sqlite3BtreeRowCountEst(pCrsr);
+  }else{
+    nEntry = 0;  /* Not needed.  Only used to silence a warning. */
+    rc = sqlite3BtreeCount(db, pCrsr, &nEntry);
+    if( rc ) goto abort_due_to_error;
+  }
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = nEntry;
+  goto check_for_interrupt;
+}
+
+/* Opcode: Savepoint P1 * * P4 *
+**
+** Open, release or rollback the savepoint named by parameter P4, depending
+** on the value of P1. To open a new savepoint set P1==0 (SAVEPOINT_BEGIN).
+** To release (commit) an existing savepoint set P1==1 (SAVEPOINT_RELEASE).
+** To rollback an existing savepoint set P1==2 (SAVEPOINT_ROLLBACK).
+*/
+case OP_Savepoint: {
+  int p1;                         /* Value of P1 operand */
+  char *zName;                    /* Name of savepoint */
+  int nName;
+  Savepoint *pNew;
+  Savepoint *pSavepoint;
+  Savepoint *pTmp;
+  int iSavepoint;
+  int ii;
+
+  p1 = pOp->p1;
+  zName = pOp->p4.z;
+
+  /* Assert that the p1 parameter is valid. Also that if there is no open
+  ** transaction, then there cannot be any savepoints.
+  */
+  assert( db->pSavepoint==0 || db->autoCommit==0 );
+  assert( p1==SAVEPOINT_BEGIN||p1==SAVEPOINT_RELEASE||p1==SAVEPOINT_ROLLBACK );
+  assert( db->pSavepoint || db->isTransactionSavepoint==0 );
+  assert( checkSavepointCount(db) );
+  assert( p->bIsReader );
+
+  if( p1==SAVEPOINT_BEGIN ){
+    if( db->nVdbeWrite>0 ){
+      /* A new savepoint cannot be created if there are active write
+      ** statements (i.e. open read/write incremental blob handles).
+      */
+      sqlite3VdbeError(p, "cannot open savepoint - SQL statements in progress");
+      rc = SQLITE_BUSY;
+    }else{
+      nName = sqlite3Strlen30(zName);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      /* This call is Ok even if this savepoint is actually a transaction
+      ** savepoint (and therefore should not prompt xSavepoint()) callbacks.
+      ** If this is a transaction savepoint being opened, it is guaranteed
+      ** that the db->aVTrans[] array is empty.  */
+      assert( db->autoCommit==0 || db->nVTrans==0 );
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN,
+                                db->nStatement+db->nSavepoint);
+      if( rc!=SQLITE_OK ) goto abort_due_to_error;
+#endif
+
+      /* Create a new savepoint structure. */
+      pNew = sqlite3DbMallocRawNN(db, sizeof(Savepoint)+nName+1);
+      if( pNew ){
+        pNew->zName = (char *)&pNew[1];
+        memcpy(pNew->zName, zName, nName+1);
+
+        /* If there is no open transaction, then mark this as a special
+        ** "transaction savepoint". */
+        if( db->autoCommit ){
+          db->autoCommit = 0;
+          db->isTransactionSavepoint = 1;
+        }else{
+          db->nSavepoint++;
+        }
+
+        /* Link the new savepoint into the database handle's list. */
+        pNew->pNext = db->pSavepoint;
+        db->pSavepoint = pNew;
+        pNew->nDeferredCons = db->nDeferredCons;
+        pNew->nDeferredImmCons = db->nDeferredImmCons;
+      }
+    }
+  }else{
+    assert( p1==SAVEPOINT_RELEASE || p1==SAVEPOINT_ROLLBACK );
+    iSavepoint = 0;
+
+    /* Find the named savepoint. If there is no such savepoint, then an
+    ** an error is returned to the user.  */
+    for(
+      pSavepoint = db->pSavepoint;
+      pSavepoint && sqlite3StrICmp(pSavepoint->zName, zName);
+      pSavepoint = pSavepoint->pNext
+    ){
+      iSavepoint++;
+    }
+    if( !pSavepoint ){
+      sqlite3VdbeError(p, "no such savepoint: %s", zName);
+      rc = SQLITE_ERROR;
+    }else if( db->nVdbeWrite>0 && p1==SAVEPOINT_RELEASE ){
+      /* It is not possible to release (commit) a savepoint if there are
+      ** active write statements.
+      */
+      sqlite3VdbeError(p, "cannot release savepoint - "
+                          "SQL statements in progress");
+      rc = SQLITE_BUSY;
+    }else{
+
+      /* Determine whether or not this is a transaction savepoint. If so,
+      ** and this is a RELEASE command, then the current transaction
+      ** is committed.
+      */
+      int isTransaction = pSavepoint->pNext==0 && db->isTransactionSavepoint;
+      if( isTransaction && p1==SAVEPOINT_RELEASE ){
+        if( (rc = sqlite3VdbeCheckFk(p, 1))!=SQLITE_OK ){
+          goto vdbe_return;
+        }
+        db->autoCommit = 1;
+        if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
+          p->pc = (int)(pOp - aOp);
+          db->autoCommit = 0;
+          p->rc = rc = SQLITE_BUSY;
+          goto vdbe_return;
+        }
+        rc = p->rc;
+        if( rc ){
+          db->autoCommit = 0;
+        }else{
+          db->isTransactionSavepoint = 0;
+        }
+      }else{
+        int isSchemaChange;
+        iSavepoint = db->nSavepoint - iSavepoint - 1;
+        if( p1==SAVEPOINT_ROLLBACK ){
+          isSchemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0;
+          for(ii=0; ii<db->nDb; ii++){
+            rc = sqlite3BtreeTripAllCursors(db->aDb[ii].pBt,
+                                       SQLITE_ABORT_ROLLBACK,
+                                       isSchemaChange==0);
+            if( rc!=SQLITE_OK ) goto abort_due_to_error;
+          }
+        }else{
+          assert( p1==SAVEPOINT_RELEASE );
+          isSchemaChange = 0;
+        }
+        for(ii=0; ii<db->nDb; ii++){
+          rc = sqlite3BtreeSavepoint(db->aDb[ii].pBt, p1, iSavepoint);
+          if( rc!=SQLITE_OK ){
+            goto abort_due_to_error;
+          }
+        }
+        if( isSchemaChange ){
+          sqlite3ExpirePreparedStatements(db, 0);
+          sqlite3ResetAllSchemasOfConnection(db);
+          db->mDbFlags |= DBFLAG_SchemaChange;
+        }
+      }
+      if( rc ) goto abort_due_to_error;
+
+      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all
+      ** savepoints nested inside of the savepoint being operated on. */
+      while( db->pSavepoint!=pSavepoint ){
+        pTmp = db->pSavepoint;
+        db->pSavepoint = pTmp->pNext;
+        sqlite3DbFree(db, pTmp);
+        db->nSavepoint--;
+      }
+
+      /* If it is a RELEASE, then destroy the savepoint being operated on
+      ** too. If it is a ROLLBACK TO, then set the number of deferred
+      ** constraint violations present in the database to the value stored
+      ** when the savepoint was created.  */
+      if( p1==SAVEPOINT_RELEASE ){
+        assert( pSavepoint==db->pSavepoint );
+        db->pSavepoint = pSavepoint->pNext;
+        sqlite3DbFree(db, pSavepoint);
+        if( !isTransaction ){
+          db->nSavepoint--;
+        }
+      }else{
+        assert( p1==SAVEPOINT_ROLLBACK );
+        db->nDeferredCons = pSavepoint->nDeferredCons;
+        db->nDeferredImmCons = pSavepoint->nDeferredImmCons;
+      }
+
+      if( !isTransaction || p1==SAVEPOINT_ROLLBACK ){
+        rc = sqlite3VtabSavepoint(db, p1, iSavepoint);
+        if( rc!=SQLITE_OK ) goto abort_due_to_error;
+      }
+    }
+  }
+  if( rc ) goto abort_due_to_error;
+  if( p->eVdbeState==VDBE_HALT_STATE ){
+    rc = SQLITE_DONE;
+    goto vdbe_return;
+  }
+  break;
+}
+
+/* Opcode: AutoCommit P1 P2 * * *
+**
+** Set the database auto-commit flag to P1 (1 or 0). If P2 is true, roll
+** back any currently active btree transactions. If there are any active
+** VMs (apart from this one), then a ROLLBACK fails.  A COMMIT fails if
+** there are active writing VMs or active VMs that use shared cache.
+**
+** This instruction causes the VM to halt.
+*/
+case OP_AutoCommit: {
+  int desiredAutoCommit;
+  int iRollback;
+
+  desiredAutoCommit = pOp->p1;
+  iRollback = pOp->p2;
+  assert( desiredAutoCommit==1 || desiredAutoCommit==0 );
+  assert( desiredAutoCommit==1 || iRollback==0 );
+  assert( db->nVdbeActive>0 );  /* At least this one VM is active */
+  assert( p->bIsReader );
+
+  if( desiredAutoCommit!=db->autoCommit ){
+    if( iRollback ){
+      assert( desiredAutoCommit==1 );
+      sqlite3RollbackAll(db, SQLITE_ABORT_ROLLBACK);
+      db->autoCommit = 1;
+    }else if( desiredAutoCommit && db->nVdbeWrite>0 ){
+      /* If this instruction implements a COMMIT and other VMs are writing
+      ** return an error indicating that the other VMs must complete first.
+      */
+      sqlite3VdbeError(p, "cannot commit transaction - "
+                          "SQL statements in progress");
+      rc = SQLITE_BUSY;
+      goto abort_due_to_error;
+    }else if( (rc = sqlite3VdbeCheckFk(p, 1))!=SQLITE_OK ){
+      goto vdbe_return;
+    }else{
+      db->autoCommit = (u8)desiredAutoCommit;
+    }
+    if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
+      p->pc = (int)(pOp - aOp);
+      db->autoCommit = (u8)(1-desiredAutoCommit);
+      p->rc = rc = SQLITE_BUSY;
+      goto vdbe_return;
+    }
+    sqlite3CloseSavepoints(db);
+    if( p->rc==SQLITE_OK ){
+      rc = SQLITE_DONE;
+    }else{
+      rc = SQLITE_ERROR;
+    }
+    goto vdbe_return;
+  }else{
+    sqlite3VdbeError(p,
+        (!desiredAutoCommit)?"cannot start a transaction within a transaction":(
+        (iRollback)?"cannot rollback - no transaction is active":
+                   "cannot commit - no transaction is active"));
+
+    rc = SQLITE_ERROR;
+    goto abort_due_to_error;
+  }
+  /*NOTREACHED*/ assert(0);
+}
+
+/* Opcode: Transaction P1 P2 P3 P4 P5
+**
+** Begin a transaction on database P1 if a transaction is not already
+** active.
+** If P2 is non-zero, then a write-transaction is started, or if a
+** read-transaction is already active, it is upgraded to a write-transaction.
+** If P2 is zero, then a read-transaction is started.  If P2 is 2 or more
+** then an exclusive transaction is started.
+**
+** P1 is the index of the database file on which the transaction is
+** started.  Index 0 is the main database file and index 1 is the
+** file used for temporary tables.  Indices of 2 or more are used for
+** attached databases.
+**
+** If a write-transaction is started and the Vdbe.usesStmtJournal flag is
+** true (this flag is set if the Vdbe may modify more than one row and may
+** throw an ABORT exception), a statement transaction may also be opened.
+** More specifically, a statement transaction is opened iff the database
+** connection is currently not in autocommit mode, or if there are other
+** active statements. A statement transaction allows the changes made by this
+** VDBE to be rolled back after an error without having to roll back the
+** entire transaction. If no error is encountered, the statement transaction
+** will automatically commit when the VDBE halts.
+**
+** If P5!=0 then this opcode also checks the schema cookie against P3
+** and the schema generation counter against P4.
+** The cookie changes its value whenever the database schema changes.
+** This operation is used to detect when that the cookie has changed
+** and that the current process needs to reread the schema.  If the schema
+** cookie in P3 differs from the schema cookie in the database header or
+** if the schema generation counter in P4 differs from the current
+** generation counter, then an SQLITE_SCHEMA error is raised and execution
+** halts.  The sqlite3_step() wrapper function might then reprepare the
+** statement and rerun it from the beginning.
+*/
+case OP_Transaction: {
+  Btree *pBt;
+  Db *pDb;
+  int iMeta = 0;
+
+  assert( p->bIsReader );
+  assert( p->readOnly==0 || pOp->p2==0 );
+  assert( pOp->p2>=0 && pOp->p2<=2 );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p1) );
+  assert( rc==SQLITE_OK );
+  if( pOp->p2 && (db->flags & (SQLITE_QueryOnly|SQLITE_CorruptRdOnly))!=0 ){
+    if( db->flags & SQLITE_QueryOnly ){
+      /* Writes prohibited by the "PRAGMA query_only=TRUE" statement */
+      rc = SQLITE_READONLY;
+    }else{
+      /* Writes prohibited due to a prior SQLITE_CORRUPT in the current
+      ** transaction */
+      rc = SQLITE_CORRUPT;
+    }
+    goto abort_due_to_error;
+  }
+  pDb = &db->aDb[pOp->p1];
+  pBt = pDb->pBt;
+
+  if( pBt ){
+    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2, &iMeta);
+    testcase( rc==SQLITE_BUSY_SNAPSHOT );
+    testcase( rc==SQLITE_BUSY_RECOVERY );
+    if( rc!=SQLITE_OK ){
+      if( (rc&0xff)==SQLITE_BUSY ){
+        p->pc = (int)(pOp - aOp);
+        p->rc = rc;
+        goto vdbe_return;
+      }
+      goto abort_due_to_error;
+    }
+
+    if( p->usesStmtJournal
+     && pOp->p2
+     && (db->autoCommit==0 || db->nVdbeRead>1)
+    ){
+      assert( sqlite3BtreeTxnState(pBt)==SQLITE_TXN_WRITE );
+      if( p->iStatement==0 ){
+        assert( db->nStatement>=0 && db->nSavepoint>=0 );
+        db->nStatement++;
+        p->iStatement = db->nSavepoint + db->nStatement;
+      }
+
+      rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN, p->iStatement-1);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3BtreeBeginStmt(pBt, p->iStatement);
+      }
+
+      /* Store the current value of the database handles deferred constraint
+      ** counter. If the statement transaction needs to be rolled back,
+      ** the value of this counter needs to be restored too.  */
+      p->nStmtDefCons = db->nDeferredCons;
+      p->nStmtDefImmCons = db->nDeferredImmCons;
+    }
+  }
+  assert( pOp->p5==0 || pOp->p4type==P4_INT32 );
+  if( rc==SQLITE_OK
+   && pOp->p5
+   && (iMeta!=pOp->p3 || pDb->pSchema->iGeneration!=pOp->p4.i)
+  ){
+    /*
+    ** IMPLEMENTATION-OF: R-03189-51135 As each SQL statement runs, the schema
+    ** version is checked to ensure that the schema has not changed since the
+    ** SQL statement was prepared.
+    */
+    sqlite3DbFree(db, p->zErrMsg);
+    p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
+    /* If the schema-cookie from the database file matches the cookie
+    ** stored with the in-memory representation of the schema, do
+    ** not reload the schema from the database file.
+    **
+    ** If virtual-tables are in use, this is not just an optimization.
+    ** Often, v-tables store their data in other SQLite tables, which
+    ** are queried from within xNext() and other v-table methods using
+    ** prepared queries. If such a query is out-of-date, we do not want to
+    ** discard the database schema, as the user code implementing the
+    ** v-table would have to be ready for the sqlite3_vtab structure itself
+    ** to be invalidated whenever sqlite3_step() is called from within
+    ** a v-table method.
+    */
+    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
+      sqlite3ResetOneSchema(db, pOp->p1);
+    }
+    p->expired = 1;
+    rc = SQLITE_SCHEMA;
+
+    /* Set changeCntOn to 0 to prevent the value returned by sqlite3_changes()
+    ** from being modified in sqlite3VdbeHalt(). If this statement is
+    ** reprepared, changeCntOn will be set again. */
+    p->changeCntOn = 0;
+  }
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: ReadCookie P1 P2 P3 * *
+**
+** Read cookie number P3 from database P1 and write it into register P2.
+** P3==1 is the schema version.  P3==2 is the database format.
+** P3==3 is the recommended pager cache size, and so forth.  P1==0 is
+** the main database file and P1==1 is the database file used to store
+** temporary tables.
+**
+** There must be a read-lock on the database (either a transaction
+** must be started or there must be an open cursor) before
+** executing this instruction.
+*/
+case OP_ReadCookie: {               /* out2 */
+  int iMeta;
+  int iDb;
+  int iCookie;
+
+  assert( p->bIsReader );
+  iDb = pOp->p1;
+  iCookie = pOp->p3;
+  assert( pOp->p3<SQLITE_N_BTREE_META );
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( db->aDb[iDb].pBt!=0 );
+  assert( DbMaskTest(p->btreeMask, iDb) );
+
+  sqlite3BtreeGetMeta(db->aDb[iDb].pBt, iCookie, (u32 *)&iMeta);
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = iMeta;
+  break;
+}
+
+/* Opcode: SetCookie P1 P2 P3 * P5
+**
+** Write the integer value P3 into cookie number P2 of database P1.
+** P2==1 is the schema version.  P2==2 is the database format.
+** P2==3 is the recommended pager cache
+** size, and so forth.  P1==0 is the main database file and P1==1 is the
+** database file used to store temporary tables.
+**
+** A transaction must be started before executing this opcode.
+**
+** If P2 is the SCHEMA_VERSION cookie (cookie number 1) then the internal
+** schema version is set to P3-P5.  The "PRAGMA schema_version=N" statement
+** has P5 set to 1, so that the internal schema version will be different
+** from the database schema version, resulting in a schema reset.
+*/
+case OP_SetCookie: {
+  Db *pDb;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  assert( pOp->p2<SQLITE_N_BTREE_META );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p1) );
+  assert( p->readOnly==0 );
+  pDb = &db->aDb[pOp->p1];
+  assert( pDb->pBt!=0 );
+  assert( sqlite3SchemaMutexHeld(db, pOp->p1, 0) );
+  /* See note about index shifting on OP_ReadCookie */
+  rc = sqlite3BtreeUpdateMeta(pDb->pBt, pOp->p2, pOp->p3);
+  if( pOp->p2==BTREE_SCHEMA_VERSION ){
+    /* When the schema cookie changes, record the new cookie internally */
+    *(u32*)&pDb->pSchema->schema_cookie = *(u32*)&pOp->p3 - pOp->p5;
+    db->mDbFlags |= DBFLAG_SchemaChange;
+    sqlite3FkClearTriggerCache(db, pOp->p1);
+  }else if( pOp->p2==BTREE_FILE_FORMAT ){
+    /* Record changes in the file format */
+    pDb->pSchema->file_format = pOp->p3;
+  }
+  if( pOp->p1==1 ){
+    /* Invalidate all prepared statements whenever the TEMP database
+    ** schema is changed.  Ticket #1644 */
+    sqlite3ExpirePreparedStatements(db, 0);
+    p->expired = 0;
+  }
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: OpenRead P1 P2 P3 P4 P5
+** Synopsis: root=P2 iDb=P3
+**
+** Open a read-only cursor for the database table whose root page is
+** P2 in a database file.  The database file is determined by P3.
+** P3==0 means the main database, P3==1 means the database used for
+** temporary tables, and P3>1 means used the corresponding attached
+** database.  Give the new cursor an identifier of P1.  The P1
+** values need not be contiguous but all P1 values should be small integers.
+** It is an error for P1 to be negative.
+**
+** Allowed P5 bits:
+** <ul>
+** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
+**       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
+**       of OP_SeekLE/OP_IdxLT)
+** </ul>
+**
+** The P4 value may be either an integer (P4_INT32) or a pointer to
+** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo
+** object, then table being opened must be an [index b-tree] where the
+** KeyInfo object defines the content and collating
+** sequence of that index b-tree. Otherwise, if P4 is an integer
+** value, then the table being opened must be a [table b-tree] with a
+** number of columns no less than the value of P4.
+**
+** See also: OpenWrite, ReopenIdx
+*/
+/* Opcode: ReopenIdx P1 P2 P3 P4 P5
+** Synopsis: root=P2 iDb=P3
+**
+** The ReopenIdx opcode works like OP_OpenRead except that it first
+** checks to see if the cursor on P1 is already open on the same
+** b-tree and if it is this opcode becomes a no-op.  In other words,
+** if the cursor is already open, do not reopen it.
+**
+** The ReopenIdx opcode may only be used with P5==0 or P5==OPFLAG_SEEKEQ
+** and with P4 being a P4_KEYINFO object.  Furthermore, the P3 value must
+** be the same as every other ReopenIdx or OpenRead for the same cursor
+** number.
+**
+** Allowed P5 bits:
+** <ul>
+** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
+**       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
+**       of OP_SeekLE/OP_IdxLT)
+** </ul>
+**
+** See also: OP_OpenRead, OP_OpenWrite
+*/
+/* Opcode: OpenWrite P1 P2 P3 P4 P5
+** Synopsis: root=P2 iDb=P3
+**
+** Open a read/write cursor named P1 on the table or index whose root
+** page is P2 (or whose root page is held in register P2 if the
+** OPFLAG_P2ISREG bit is set in P5 - see below).
+**
+** The P4 value may be either an integer (P4_INT32) or a pointer to
+** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo
+** object, then table being opened must be an [index b-tree] where the
+** KeyInfo object defines the content and collating
+** sequence of that index b-tree. Otherwise, if P4 is an integer
+** value, then the table being opened must be a [table b-tree] with a
+** number of columns no less than the value of P4.
+**
+** Allowed P5 bits:
+** <ul>
+** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
+**       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
+**       of OP_SeekLE/OP_IdxLT)
+** <li>  <b>0x08 OPFLAG_FORDELETE</b>: This cursor is used only to seek
+**       and subsequently delete entries in an index btree.  This is a
+**       hint to the storage engine that the storage engine is allowed to
+**       ignore.  The hint is not used by the official SQLite b*tree storage
+**       engine, but is used by COMDB2.
+** <li>  <b>0x10 OPFLAG_P2ISREG</b>: Use the content of register P2
+**       as the root page, not the value of P2 itself.
+** </ul>
+**
+** This instruction works like OpenRead except that it opens the cursor
+** in read/write mode.
+**
+** See also: OP_OpenRead, OP_ReopenIdx
+*/
+case OP_ReopenIdx: {         /* ncycle */
+  int nField;
+  KeyInfo *pKeyInfo;
+  u32 p2;
+  int iDb;
+  int wrFlag;
+  Btree *pX;
+  VdbeCursor *pCur;
+  Db *pDb;
+
+  assert( pOp->p5==0 || pOp->p5==OPFLAG_SEEKEQ );
+  assert( pOp->p4type==P4_KEYINFO );
+  pCur = p->apCsr[pOp->p1];
+  if( pCur && pCur->pgnoRoot==(u32)pOp->p2 ){
+    assert( pCur->iDb==pOp->p3 );      /* Guaranteed by the code generator */
+    assert( pCur->eCurType==CURTYPE_BTREE );
+    sqlite3BtreeClearCursor(pCur->uc.pCursor);
+    goto open_cursor_set_hints;
+  }
+  /* If the cursor is not currently open or is open on a different
+  ** index, then fall through into OP_OpenRead to force a reopen */
+case OP_OpenRead:            /* ncycle */
+case OP_OpenWrite:
+
+  assert( pOp->opcode==OP_OpenWrite || pOp->p5==0 || pOp->p5==OPFLAG_SEEKEQ );
+  assert( p->bIsReader );
+  assert( pOp->opcode==OP_OpenRead || pOp->opcode==OP_ReopenIdx
+          || p->readOnly==0 );
+
+  if( p->expired==1 ){
+    rc = SQLITE_ABORT_ROLLBACK;
+    goto abort_due_to_error;
+  }
+
+  nField = 0;
+  pKeyInfo = 0;
+  p2 = (u32)pOp->p2;
+  iDb = pOp->p3;
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( DbMaskTest(p->btreeMask, iDb) );
+  pDb = &db->aDb[iDb];
+  pX = pDb->pBt;
+  assert( pX!=0 );
+  if( pOp->opcode==OP_OpenWrite ){
+    assert( OPFLAG_FORDELETE==BTREE_FORDELETE );
+    wrFlag = BTREE_WRCSR | (pOp->p5 & OPFLAG_FORDELETE);
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( pDb->pSchema->file_format < p->minWriteFileFormat ){
+      p->minWriteFileFormat = pDb->pSchema->file_format;
+    }
+    if( pOp->p5 & OPFLAG_P2ISREG ){
+      assert( p2>0 );
+      assert( p2<=(u32)(p->nMem+1 - p->nCursor) );
+      pIn2 = &aMem[p2];
+      assert( memIsValid(pIn2) );
+      assert( (pIn2->flags & MEM_Int)!=0 );
+      sqlite3VdbeMemIntegerify(pIn2);
+      p2 = (int)pIn2->u.i;
+      /* The p2 value always comes from a prior OP_CreateBtree opcode and
+      ** that opcode will always set the p2 value to 2 or more or else fail.
+      ** If there were a failure, the prepared statement would have halted
+      ** before reaching this instruction. */
+      assert( p2>=2 );
+    }
+  }else{
+    wrFlag = 0;
+    assert( (pOp->p5 & OPFLAG_P2ISREG)==0 );
+  }
+  if( pOp->p4type==P4_KEYINFO ){
+    pKeyInfo = pOp->p4.pKeyInfo;
+    assert( pKeyInfo->enc==ENC(db) );
+    assert( pKeyInfo->db==db );
+    nField = pKeyInfo->nAllField;
+  }else if( pOp->p4type==P4_INT32 ){
+    nField = pOp->p4.i;
+  }
+  assert( pOp->p1>=0 );
+  assert( nField>=0 );
+  testcase( nField==0 );  /* Table with INTEGER PRIMARY KEY and nothing else */
+  pCur = allocateCursor(p, pOp->p1, nField, CURTYPE_BTREE);
+  if( pCur==0 ) goto no_mem;
+  pCur->iDb = iDb;
+  pCur->nullRow = 1;
+  pCur->isOrdered = 1;
+  pCur->pgnoRoot = p2;
+#ifdef SQLITE_DEBUG
+  pCur->wrFlag = wrFlag;
+#endif
+  rc = sqlite3BtreeCursor(pX, p2, wrFlag, pKeyInfo, pCur->uc.pCursor);
+  pCur->pKeyInfo = pKeyInfo;
+  /* Set the VdbeCursor.isTable variable. Previous versions of
+  ** SQLite used to check if the root-page flags were sane at this point
+  ** and report database corruption if they were not, but this check has
+  ** since moved into the btree layer.  */
+  pCur->isTable = pOp->p4type!=P4_KEYINFO;
+
+open_cursor_set_hints:
+  assert( OPFLAG_BULKCSR==BTREE_BULKLOAD );
+  assert( OPFLAG_SEEKEQ==BTREE_SEEK_EQ );
+  testcase( pOp->p5 & OPFLAG_BULKCSR );
+  testcase( pOp->p2 & OPFLAG_SEEKEQ );
+  sqlite3BtreeCursorHintFlags(pCur->uc.pCursor,
+                               (pOp->p5 & (OPFLAG_BULKCSR|OPFLAG_SEEKEQ)));
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: OpenDup P1 P2 * * *
+**
+** Open a new cursor P1 that points to the same ephemeral table as
+** cursor P2.  The P2 cursor must have been opened by a prior OP_OpenEphemeral
+** opcode.  Only ephemeral cursors may be duplicated.
+**
+** Duplicate ephemeral cursors are used for self-joins of materialized views.
+*/
+case OP_OpenDup: {           /* ncycle */
+  VdbeCursor *pOrig;    /* The original cursor to be duplicated */
+  VdbeCursor *pCx;      /* The new cursor */
+
+  pOrig = p->apCsr[pOp->p2];
+  assert( pOrig );
+  assert( pOrig->isEphemeral );  /* Only ephemeral cursors can be duplicated */
+
+  pCx = allocateCursor(p, pOp->p1, pOrig->nField, CURTYPE_BTREE);
+  if( pCx==0 ) goto no_mem;
+  pCx->nullRow = 1;
+  pCx->isEphemeral = 1;
+  pCx->pKeyInfo = pOrig->pKeyInfo;
+  pCx->isTable = pOrig->isTable;
+  pCx->pgnoRoot = pOrig->pgnoRoot;
+  pCx->isOrdered = pOrig->isOrdered;
+  pCx->ub.pBtx = pOrig->ub.pBtx;
+  pCx->noReuse = 1;
+  pOrig->noReuse = 1;
+  rc = sqlite3BtreeCursor(pCx->ub.pBtx, pCx->pgnoRoot, BTREE_WRCSR,
+                          pCx->pKeyInfo, pCx->uc.pCursor);
+  /* The sqlite3BtreeCursor() routine can only fail for the first cursor
+  ** opened for a database.  Since there is already an open cursor when this
+  ** opcode is run, the sqlite3BtreeCursor() cannot fail */
+  assert( rc==SQLITE_OK );
+  break;
+}
+
+
+/* Opcode: OpenEphemeral P1 P2 P3 P4 P5
+** Synopsis: nColumn=P2
+**
+** Open a new cursor P1 to a transient table.
+** The cursor is always opened read/write even if
+** the main database is read-only.  The ephemeral
+** table is deleted automatically when the cursor is closed.
+**
+** If the cursor P1 is already opened on an ephemeral table, the table
+** is cleared (all content is erased).
+**
+** P2 is the number of columns in the ephemeral table.
+** The cursor points to a BTree table if P4==0 and to a BTree index
+** if P4 is not 0.  If P4 is not NULL, it points to a KeyInfo structure
+** that defines the format of keys in the index.
+**
+** The P5 parameter can be a mask of the BTREE_* flags defined
+** in btree.h.  These flags control aspects of the operation of
+** the btree.  The BTREE_OMIT_JOURNAL and BTREE_SINGLE flags are
+** added automatically.
+**
+** If P3 is positive, then reg[P3] is modified slightly so that it
+** can be used as zero-length data for OP_Insert.  This is an optimization
+** that avoids an extra OP_Blob opcode to initialize that register.
+*/
+/* Opcode: OpenAutoindex P1 P2 * P4 *
+** Synopsis: nColumn=P2
+**
+** This opcode works the same as OP_OpenEphemeral.  It has a
+** different name to distinguish its use.  Tables created using
+** by this opcode will be used for automatically created transient
+** indices in joins.
+*/
+case OP_OpenAutoindex:       /* ncycle */
+case OP_OpenEphemeral: {     /* ncycle */
+  VdbeCursor *pCx;
+  KeyInfo *pKeyInfo;
+
+  static const int vfsFlags =
+      SQLITE_OPEN_READWRITE |
+      SQLITE_OPEN_CREATE |
+      SQLITE_OPEN_EXCLUSIVE |
+      SQLITE_OPEN_DELETEONCLOSE |
+      SQLITE_OPEN_TRANSIENT_DB;
+  assert( pOp->p1>=0 );
+  assert( pOp->p2>=0 );
+  if( pOp->p3>0 ){
+    /* Make register reg[P3] into a value that can be used as the data
+    ** form sqlite3BtreeInsert() where the length of the data is zero. */
+    assert( pOp->p2==0 ); /* Only used when number of columns is zero */
+    assert( pOp->opcode==OP_OpenEphemeral );
+    assert( aMem[pOp->p3].flags & MEM_Null );
+    aMem[pOp->p3].n = 0;
+    aMem[pOp->p3].z = "";
+  }
+  pCx = p->apCsr[pOp->p1];
+  if( pCx && !pCx->noReuse &&  ALWAYS(pOp->p2<=pCx->nField) ){
+    /* If the ephemeral table is already open and has no duplicates from
+    ** OP_OpenDup, then erase all existing content so that the table is
+    ** empty again, rather than creating a new table. */
+    assert( pCx->isEphemeral );
+    pCx->seqCount = 0;
+    pCx->cacheStatus = CACHE_STALE;
+    rc = sqlite3BtreeClearTable(pCx->ub.pBtx, pCx->pgnoRoot, 0);
+  }else{
+    pCx = allocateCursor(p, pOp->p1, pOp->p2, CURTYPE_BTREE);
+    if( pCx==0 ) goto no_mem;
+    pCx->isEphemeral = 1;
+    rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pCx->ub.pBtx,
+                          BTREE_OMIT_JOURNAL | BTREE_SINGLE | pOp->p5,
+                          vfsFlags);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3BtreeBeginTrans(pCx->ub.pBtx, 1, 0);
+      if( rc==SQLITE_OK ){
+        /* If a transient index is required, create it by calling
+        ** sqlite3BtreeCreateTable() with the BTREE_BLOBKEY flag before
+        ** opening it. If a transient table is required, just use the
+        ** automatically created table with root-page 1 (an BLOB_INTKEY table).
+        */
+        if( (pCx->pKeyInfo = pKeyInfo = pOp->p4.pKeyInfo)!=0 ){
+          assert( pOp->p4type==P4_KEYINFO );
+          rc = sqlite3BtreeCreateTable(pCx->ub.pBtx, &pCx->pgnoRoot,
+              BTREE_BLOBKEY | pOp->p5);
+          if( rc==SQLITE_OK ){
+            assert( pCx->pgnoRoot==SCHEMA_ROOT+1 );
+            assert( pKeyInfo->db==db );
+            assert( pKeyInfo->enc==ENC(db) );
+            rc = sqlite3BtreeCursor(pCx->ub.pBtx, pCx->pgnoRoot, BTREE_WRCSR,
+                pKeyInfo, pCx->uc.pCursor);
+          }
+          pCx->isTable = 0;
+        }else{
+          pCx->pgnoRoot = SCHEMA_ROOT;
+          rc = sqlite3BtreeCursor(pCx->ub.pBtx, SCHEMA_ROOT, BTREE_WRCSR,
+              0, pCx->uc.pCursor);
+          pCx->isTable = 1;
+        }
+      }
+      pCx->isOrdered = (pOp->p5!=BTREE_UNORDERED);
+      assert( p->apCsr[pOp->p1]==pCx );
+      if( rc ){
+        assert( !sqlite3BtreeClosesWithCursor(pCx->ub.pBtx, pCx->uc.pCursor) );
+        sqlite3BtreeClose(pCx->ub.pBtx);
+        p->apCsr[pOp->p1] = 0;  /* Not required; helps with static analysis */
+      }else{
+        assert( sqlite3BtreeClosesWithCursor(pCx->ub.pBtx, pCx->uc.pCursor) );
+      }
+    }
+  }
+  if( rc ) goto abort_due_to_error;
+  pCx->nullRow = 1;
+  break;
+}
+
+/* Opcode: SorterOpen P1 P2 P3 P4 *
+**
+** This opcode works like OP_OpenEphemeral except that it opens
+** a transient index that is specifically designed to sort large
+** tables using an external merge-sort algorithm.
+**
+** If argument P3 is non-zero, then it indicates that the sorter may
+** assume that a stable sort considering the first P3 fields of each
+** key is sufficient to produce the required results.
+*/
+case OP_SorterOpen: {
+  VdbeCursor *pCx;
+
+  assert( pOp->p1>=0 );
+  assert( pOp->p2>=0 );
+  pCx = allocateCursor(p, pOp->p1, pOp->p2, CURTYPE_SORTER);
+  if( pCx==0 ) goto no_mem;
+  pCx->pKeyInfo = pOp->p4.pKeyInfo;
+  assert( pCx->pKeyInfo->db==db );
+  assert( pCx->pKeyInfo->enc==ENC(db) );
+  rc = sqlite3VdbeSorterInit(db, pOp->p3, pCx);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: SequenceTest P1 P2 * * *
+** Synopsis: if( cursor[P1].ctr++ ) pc = P2
+**
+** P1 is a sorter cursor. If the sequence counter is currently zero, jump
+** to P2. Regardless of whether or not the jump is taken, increment the
+** the sequence value.
+*/
+case OP_SequenceTest: {
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( isSorter(pC) );
+  if( (pC->seqCount++)==0 ){
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: OpenPseudo P1 P2 P3 * *
+** Synopsis: P3 columns in r[P2]
+**
+** Open a new cursor that points to a fake table that contains a single
+** row of data.  The content of that one row is the content of memory
+** register P2.  In other words, cursor P1 becomes an alias for the
+** MEM_Blob content contained in register P2.
+**
+** A pseudo-table created by this opcode is used to hold a single
+** row output from the sorter so that the row can be decomposed into
+** individual columns using the OP_Column opcode.  The OP_Column opcode
+** is the only cursor opcode that works with a pseudo-table.
+**
+** P3 is the number of fields in the records that will be stored by
+** the pseudo-table.  If P2 is 0 or negative then the pseudo-cursor
+** will return NULL for every column.
+*/
+case OP_OpenPseudo: {
+  VdbeCursor *pCx;
+
+  assert( pOp->p1>=0 );
+  assert( pOp->p3>=0 );
+  pCx = allocateCursor(p, pOp->p1, pOp->p3, CURTYPE_PSEUDO);
+  if( pCx==0 ) goto no_mem;
+  pCx->nullRow = 1;
+  pCx->seekResult = pOp->p2;
+  pCx->isTable = 1;
+  /* Give this pseudo-cursor a fake BtCursor pointer so that pCx
+  ** can be safely passed to sqlite3VdbeCursorMoveto().  This avoids a test
+  ** for pCx->eCurType==CURTYPE_BTREE inside of sqlite3VdbeCursorMoveto()
+  ** which is a performance optimization */
+  pCx->uc.pCursor = sqlite3BtreeFakeValidCursor();
+  assert( pOp->p5==0 );
+  break;
+}
+
+/* Opcode: Close P1 * * * *
+**
+** Close a cursor previously opened as P1.  If P1 is not
+** currently open, this instruction is a no-op.
+*/
+case OP_Close: {             /* ncycle */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  sqlite3VdbeFreeCursor(p, p->apCsr[pOp->p1]);
+  p->apCsr[pOp->p1] = 0;
+  break;
+}
+
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+/* Opcode: ColumnsUsed P1 * * P4 *
+**
+** This opcode (which only exists if SQLite was compiled with
+** SQLITE_ENABLE_COLUMN_USED_MASK) identifies which columns of the
+** table or index for cursor P1 are used.  P4 is a 64-bit integer
+** (P4_INT64) in which the first 63 bits are one for each of the
+** first 63 columns of the table or index that are actually used
+** by the cursor.  The high-order bit is set if any column after
+** the 64th is used.
+*/
+case OP_ColumnsUsed: {
+  VdbeCursor *pC;
+  pC = p->apCsr[pOp->p1];
+  assert( pC->eCurType==CURTYPE_BTREE );
+  pC->maskUsed = *(u64*)pOp->p4.pI64;
+  break;
+}
+#endif
+
+/* Opcode: SeekGE P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
+** use the value in register P3 as the key.  If cursor P1 refers
+** to an SQL index, then P3 is the first in an array of P4 registers
+** that are used as an unpacked index key.
+**
+** Reposition cursor P1 so that  it points to the smallest entry that
+** is greater than or equal to the key value. If there are no records
+** greater than or equal to the key and P2 is not zero, then jump to P2.
+**
+** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
+** opcode will either land on a record that exactly matches the key, or
+** else it will cause a jump to P2.  When the cursor is OPFLAG_SEEKEQ,
+** this opcode must be followed by an IdxLE opcode with the same arguments.
+** The IdxGT opcode will be skipped if this opcode succeeds, but the
+** IdxGT opcode will be used on subsequent loop iterations.  The
+** OPFLAG_SEEKEQ flags is a hint to the btree layer to say that this
+** is an equality search.
+**
+** This opcode leaves the cursor configured to move in forward order,
+** from the beginning toward the end.  In other words, the cursor is
+** configured to use Next, not Prev.
+**
+** See also: Found, NotFound, SeekLt, SeekGt, SeekLe
+*/
+/* Opcode: SeekGT P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
+** use the value in register P3 as a key. If cursor P1 refers
+** to an SQL index, then P3 is the first in an array of P4 registers
+** that are used as an unpacked index key.
+**
+** Reposition cursor P1 so that it points to the smallest entry that
+** is greater than the key value. If there are no records greater than
+** the key and P2 is not zero, then jump to P2.
+**
+** This opcode leaves the cursor configured to move in forward order,
+** from the beginning toward the end.  In other words, the cursor is
+** configured to use Next, not Prev.
+**
+** See also: Found, NotFound, SeekLt, SeekGe, SeekLe
+*/
+/* Opcode: SeekLT P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
+** use the value in register P3 as a key. If cursor P1 refers
+** to an SQL index, then P3 is the first in an array of P4 registers
+** that are used as an unpacked index key.
+**
+** Reposition cursor P1 so that  it points to the largest entry that
+** is less than the key value. If there are no records less than
+** the key and P2 is not zero, then jump to P2.
+**
+** This opcode leaves the cursor configured to move in reverse order,
+** from the end toward the beginning.  In other words, the cursor is
+** configured to use Prev, not Next.
+**
+** See also: Found, NotFound, SeekGt, SeekGe, SeekLe
+*/
+/* Opcode: SeekLE P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
+** use the value in register P3 as a key. If cursor P1 refers
+** to an SQL index, then P3 is the first in an array of P4 registers
+** that are used as an unpacked index key.
+**
+** Reposition cursor P1 so that it points to the largest entry that
+** is less than or equal to the key value. If there are no records
+** less than or equal to the key and P2 is not zero, then jump to P2.
+**
+** This opcode leaves the cursor configured to move in reverse order,
+** from the end toward the beginning.  In other words, the cursor is
+** configured to use Prev, not Next.
+**
+** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
+** opcode will either land on a record that exactly matches the key, or
+** else it will cause a jump to P2.  When the cursor is OPFLAG_SEEKEQ,
+** this opcode must be followed by an IdxLE opcode with the same arguments.
+** The IdxGE opcode will be skipped if this opcode succeeds, but the
+** IdxGE opcode will be used on subsequent loop iterations.  The
+** OPFLAG_SEEKEQ flags is a hint to the btree layer to say that this
+** is an equality search.
+**
+** See also: Found, NotFound, SeekGt, SeekGe, SeekLt
+*/
+case OP_SeekLT:         /* jump0, in3, group, ncycle */
+case OP_SeekLE:         /* jump0, in3, group, ncycle */
+case OP_SeekGE:         /* jump0, in3, group, ncycle */
+case OP_SeekGT: {       /* jump0, in3, group, ncycle */
+  int res;           /* Comparison result */
+  int oc;            /* Opcode */
+  VdbeCursor *pC;    /* The cursor to seek */
+  UnpackedRecord r;  /* The key to seek for */
+  int nField;        /* Number of columns or fields in the key */
+  i64 iKey;          /* The rowid we are to seek to */
+  int eqOnly;        /* Only interested in == results */
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p2!=0 );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( OP_SeekLE == OP_SeekLT+1 );
+  assert( OP_SeekGE == OP_SeekLT+2 );
+  assert( OP_SeekGT == OP_SeekLT+3 );
+  assert( pC->isOrdered );
+  assert( pC->uc.pCursor!=0 );
+  oc = pOp->opcode;
+  eqOnly = 0;
+  pC->nullRow = 0;
+#ifdef SQLITE_DEBUG
+  pC->seekOp = pOp->opcode;
+#endif
+
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+  if( pC->isTable ){
+    u16 flags3, newType;
+    /* The OPFLAG_SEEKEQ/BTREE_SEEK_EQ flag is only set on index cursors */
+    assert( sqlite3BtreeCursorHasHint(pC->uc.pCursor, BTREE_SEEK_EQ)==0
+              || CORRUPT_DB );
+
+    /* The input value in P3 might be of any type: integer, real, string,
+    ** blob, or NULL.  But it needs to be an integer before we can do
+    ** the seek, so convert it. */
+    pIn3 = &aMem[pOp->p3];
+    flags3 = pIn3->flags;
+    if( (flags3 & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Str))==MEM_Str ){
+      applyNumericAffinity(pIn3, 0);
+    }
+    iKey = sqlite3VdbeIntValue(pIn3); /* Get the integer key value */
+    newType = pIn3->flags; /* Record the type after applying numeric affinity */
+    pIn3->flags = flags3;  /* But convert the type back to its original */
+
+    /* If the P3 value could not be converted into an integer without
+    ** loss of information, then special processing is required... */
+    if( (newType & (MEM_Int|MEM_IntReal))==0 ){
+      int c;
+      if( (newType & MEM_Real)==0 ){
+        if( (newType & MEM_Null) || oc>=OP_SeekGE ){
+          VdbeBranchTaken(1,2);
+          goto jump_to_p2;
+        }else{
+          rc = sqlite3BtreeLast(pC->uc.pCursor, &res);
+          if( rc!=SQLITE_OK ) goto abort_due_to_error;
+          goto seek_not_found;
+        }
+      }
+      c = sqlite3IntFloatCompare(iKey, pIn3->u.r);
+
+      /* If the approximation iKey is larger than the actual real search
+      ** term, substitute >= for > and < for <=. e.g. if the search term
+      ** is 4.9 and the integer approximation 5:
+      **
+      **        (x >  4.9)    ->     (x >= 5)
+      **        (x <= 4.9)    ->     (x <  5)
+      */
+      if( c>0 ){
+        assert( OP_SeekGE==(OP_SeekGT-1) );
+        assert( OP_SeekLT==(OP_SeekLE-1) );
+        assert( (OP_SeekLE & 0x0001)==(OP_SeekGT & 0x0001) );
+        if( (oc & 0x0001)==(OP_SeekGT & 0x0001) ) oc--;
+      }
+
+      /* If the approximation iKey is smaller than the actual real search
+      ** term, substitute <= for < and > for >=.  */
+      else if( c<0 ){
+        assert( OP_SeekLE==(OP_SeekLT+1) );
+        assert( OP_SeekGT==(OP_SeekGE+1) );
+        assert( (OP_SeekLT & 0x0001)==(OP_SeekGE & 0x0001) );
+        if( (oc & 0x0001)==(OP_SeekLT & 0x0001) ) oc++;
+      }
+    }
+    rc = sqlite3BtreeTableMoveto(pC->uc.pCursor, (u64)iKey, 0, &res);
+    pC->movetoTarget = iKey;  /* Used by OP_Delete */
+    if( rc!=SQLITE_OK ){
+      goto abort_due_to_error;
+    }
+  }else{
+    /* For a cursor with the OPFLAG_SEEKEQ/BTREE_SEEK_EQ hint, only the
+    ** OP_SeekGE and OP_SeekLE opcodes are allowed, and these must be
+    ** immediately followed by an OP_IdxGT or OP_IdxLT opcode, respectively,
+    ** with the same key.
+    */
+    if( sqlite3BtreeCursorHasHint(pC->uc.pCursor, BTREE_SEEK_EQ) ){
+      eqOnly = 1;
+      assert( pOp->opcode==OP_SeekGE || pOp->opcode==OP_SeekLE );
+      assert( pOp[1].opcode==OP_IdxLT || pOp[1].opcode==OP_IdxGT );
+      assert( pOp->opcode==OP_SeekGE || pOp[1].opcode==OP_IdxLT );
+      assert( pOp->opcode==OP_SeekLE || pOp[1].opcode==OP_IdxGT );
+      assert( pOp[1].p1==pOp[0].p1 );
+      assert( pOp[1].p2==pOp[0].p2 );
+      assert( pOp[1].p3==pOp[0].p3 );
+      assert( pOp[1].p4.i==pOp[0].p4.i );
+    }
+
+    nField = pOp->p4.i;
+    assert( pOp->p4type==P4_INT32 );
+    assert( nField>0 );
+    r.pKeyInfo = pC->pKeyInfo;
+    r.nField = (u16)nField;
+
+    /* The next line of code computes as follows, only faster:
+    **   if( oc==OP_SeekGT || oc==OP_SeekLE ){
+    **     r.default_rc = -1;
+    **   }else{
+    **     r.default_rc = +1;
+    **   }
+    */
+    r.default_rc = ((1 & (oc - OP_SeekLT)) ? -1 : +1);
+    assert( oc!=OP_SeekGT || r.default_rc==-1 );
+    assert( oc!=OP_SeekLE || r.default_rc==-1 );
+    assert( oc!=OP_SeekGE || r.default_rc==+1 );
+    assert( oc!=OP_SeekLT || r.default_rc==+1 );
+
+    r.aMem = &aMem[pOp->p3];
+#ifdef SQLITE_DEBUG
+    {
+      int i;
+      for(i=0; i<r.nField; i++){
+        assert( memIsValid(&r.aMem[i]) );
+        if( i>0 ) REGISTER_TRACE(pOp->p3+i, &r.aMem[i]);
+      }
+    }
+#endif
+    r.eqSeen = 0;
+    rc = sqlite3BtreeIndexMoveto(pC->uc.pCursor, &r, &res);
+    if( rc!=SQLITE_OK ){
+      goto abort_due_to_error;
+    }
+    if( eqOnly && r.eqSeen==0 ){
+      assert( res!=0 );
+      goto seek_not_found;
+    }
+  }
+#ifdef SQLITE_TEST
+  sqlite3_search_count++;
+#endif
+  if( oc>=OP_SeekGE ){  assert( oc==OP_SeekGE || oc==OP_SeekGT );
+    if( res<0 || (res==0 && oc==OP_SeekGT) ){
+      res = 0;
+      rc = sqlite3BtreeNext(pC->uc.pCursor, 0);
+      if( rc!=SQLITE_OK ){
+        if( rc==SQLITE_DONE ){
+          rc = SQLITE_OK;
+          res = 1;
+        }else{
+          goto abort_due_to_error;
+        }
+      }
+    }else{
+      res = 0;
+    }
+  }else{
+    assert( oc==OP_SeekLT || oc==OP_SeekLE );
+    if( res>0 || (res==0 && oc==OP_SeekLT) ){
+      res = 0;
+      rc = sqlite3BtreePrevious(pC->uc.pCursor, 0);
+      if( rc!=SQLITE_OK ){
+        if( rc==SQLITE_DONE ){
+          rc = SQLITE_OK;
+          res = 1;
+        }else{
+          goto abort_due_to_error;
+        }
+      }
+    }else{
+      /* res might be negative because the table is empty.  Check to
+      ** see if this is the case.
+      */
+      res = sqlite3BtreeEof(pC->uc.pCursor);
+    }
+  }
+seek_not_found:
+  assert( pOp->p2>0 );
+  VdbeBranchTaken(res!=0,2);
+  if( res ){
+    goto jump_to_p2;
+  }else if( eqOnly ){
+    assert( pOp[1].opcode==OP_IdxLT || pOp[1].opcode==OP_IdxGT );
+    pOp++; /* Skip the OP_IdxLt or OP_IdxGT that follows */
+  }
+  break;
+}
+
+
+/* Opcode: SeekScan  P1 P2 * * P5
+** Synopsis: Scan-ahead up to P1 rows
+**
+** This opcode is a prefix opcode to OP_SeekGE.  In other words, this
+** opcode must be immediately followed by OP_SeekGE. This constraint is
+** checked by assert() statements.
+**
+** This opcode uses the P1 through P4 operands of the subsequent
+** OP_SeekGE.  In the text that follows, the operands of the subsequent
+** OP_SeekGE opcode are denoted as SeekOP.P1 through SeekOP.P4.   Only
+** the P1, P2 and P5 operands of this opcode are also used, and  are called
+** This.P1, This.P2 and This.P5.
+**
+** This opcode helps to optimize IN operators on a multi-column index
+** where the IN operator is on the later terms of the index by avoiding
+** unnecessary seeks on the btree, substituting steps to the next row
+** of the b-tree instead.  A correct answer is obtained if this opcode
+** is omitted or is a no-op.
+**
+** The SeekGE.P3 and SeekGE.P4 operands identify an unpacked key which
+** is the desired entry that we want the cursor SeekGE.P1 to be pointing
+** to.  Call this SeekGE.P3/P4 row the "target".
+**
+** If the SeekGE.P1 cursor is not currently pointing to a valid row,
+** then this opcode is a no-op and control passes through into the OP_SeekGE.
+**
+** If the SeekGE.P1 cursor is pointing to a valid row, then that row
+** might be the target row, or it might be near and slightly before the
+** target row, or it might be after the target row.  If the cursor is
+** currently before the target row, then this opcode attempts to position
+** the cursor on or after the target row by invoking sqlite3BtreeStep()
+** on the cursor between 1 and This.P1 times.
+**
+** The This.P5 parameter is a flag that indicates what to do if the
+** cursor ends up pointing at a valid row that is past the target
+** row.  If This.P5 is false (0) then a jump is made to SeekGE.P2.  If
+** This.P5 is true (non-zero) then a jump is made to This.P2.  The P5==0
+** case occurs when there are no inequality constraints to the right of
+** the IN constraint.  The jump to SeekGE.P2 ends the loop.  The P5!=0 case
+** occurs when there are inequality constraints to the right of the IN
+** operator.  In that case, the This.P2 will point either directly to or
+** to setup code prior to the OP_IdxGT or OP_IdxGE opcode that checks for
+** loop terminate.
+**
+** Possible outcomes from this opcode:<ol>
+**
+** <li> If the cursor is initially not pointed to any valid row, then
+**      fall through into the subsequent OP_SeekGE opcode.
+**
+** <li> If the cursor is left pointing to a row that is before the target
+**      row, even after making as many as This.P1 calls to
+**      sqlite3BtreeNext(), then also fall through into OP_SeekGE.
+**
+** <li> If the cursor is left pointing at the target row, either because it
+**      was at the target row to begin with or because one or more
+**      sqlite3BtreeNext() calls moved the cursor to the target row,
+**      then jump to This.P2..,
+**
+** <li> If the cursor started out before the target row and a call to
+**      to sqlite3BtreeNext() moved the cursor off the end of the index
+**      (indicating that the target row definitely does not exist in the
+**      btree) then jump to SeekGE.P2, ending the loop.
+**
+** <li> If the cursor ends up on a valid row that is past the target row
+**      (indicating that the target row does not exist in the btree) then
+**      jump to SeekOP.P2 if This.P5==0 or to This.P2 if This.P5>0.
+** </ol>
+*/
+case OP_SeekScan: {          /* ncycle */
+  VdbeCursor *pC;
+  int res;
+  int nStep;
+  UnpackedRecord r;
+
+  assert( pOp[1].opcode==OP_SeekGE );
+
+  /* If pOp->p5 is clear, then pOp->p2 points to the first instruction past the
+  ** OP_IdxGT that follows the OP_SeekGE. Otherwise, it points to the first
+  ** opcode past the OP_SeekGE itself.  */
+  assert( pOp->p2>=(int)(pOp-aOp)+2 );
+#ifdef SQLITE_DEBUG
+  if( pOp->p5==0 ){
+    /* There are no inequality constraints following the IN constraint. */
+    assert( pOp[1].p1==aOp[pOp->p2-1].p1 );
+    assert( pOp[1].p2==aOp[pOp->p2-1].p2 );
+    assert( pOp[1].p3==aOp[pOp->p2-1].p3 );
+    assert( aOp[pOp->p2-1].opcode==OP_IdxGT
+         || aOp[pOp->p2-1].opcode==OP_IdxGE );
+    testcase( aOp[pOp->p2-1].opcode==OP_IdxGE );
+  }else{
+    /* There are inequality constraints.  */
+    assert( pOp->p2==(int)(pOp-aOp)+2 );
+    assert( aOp[pOp->p2-1].opcode==OP_SeekGE );
+  }
+#endif
+
+  assert( pOp->p1>0 );
+  pC = p->apCsr[pOp[1].p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( !pC->isTable );
+  if( !sqlite3BtreeCursorIsValidNN(pC->uc.pCursor) ){
+#ifdef SQLITE_DEBUG
+     if( db->flags&SQLITE_VdbeTrace ){
+       printf("... cursor not valid - fall through\n");
+     }
+#endif
+    break;
+  }
+  nStep = pOp->p1;
+  assert( nStep>=1 );
+  r.pKeyInfo = pC->pKeyInfo;
+  r.nField = (u16)pOp[1].p4.i;
+  r.default_rc = 0;
+  r.aMem = &aMem[pOp[1].p3];
+#ifdef SQLITE_DEBUG
+  {
+    int i;
+    for(i=0; i<r.nField; i++){
+      assert( memIsValid(&r.aMem[i]) );
+      REGISTER_TRACE(pOp[1].p3+i, &aMem[pOp[1].p3+i]);
+    }
+  }
+#endif
+  res = 0;  /* Not needed.  Only used to silence a warning. */
+  while(1){
+    rc = sqlite3VdbeIdxKeyCompare(db, pC, &r, &res);
+    if( rc ) goto abort_due_to_error;
+    if( res>0 && pOp->p5==0 ){
+      seekscan_search_fail:
+      /* Jump to SeekGE.P2, ending the loop */
+#ifdef SQLITE_DEBUG
+      if( db->flags&SQLITE_VdbeTrace ){
+        printf("... %d steps and then skip\n", pOp->p1 - nStep);
+      }
+#endif
+      VdbeBranchTaken(1,3);
+      pOp++;
+      goto jump_to_p2;
+    }
+    if( res>=0 ){
+      /* Jump to This.P2, bypassing the OP_SeekGE opcode */
+#ifdef SQLITE_DEBUG
+      if( db->flags&SQLITE_VdbeTrace ){
+        printf("... %d steps and then success\n", pOp->p1 - nStep);
+      }
+#endif
+      VdbeBranchTaken(2,3);
+      goto jump_to_p2;
+      break;
+    }
+    if( nStep<=0 ){
+#ifdef SQLITE_DEBUG
+      if( db->flags&SQLITE_VdbeTrace ){
+        printf("... fall through after %d steps\n", pOp->p1);
+      }
+#endif
+      VdbeBranchTaken(0,3);
+      break;
+    }
+    nStep--;
+    pC->cacheStatus = CACHE_STALE;
+    rc = sqlite3BtreeNext(pC->uc.pCursor, 0);
+    if( rc ){
+      if( rc==SQLITE_DONE ){
+        rc = SQLITE_OK;
+        goto seekscan_search_fail;
+      }else{
+        goto abort_due_to_error;
+      }
+    }
+  }
+
+  break;
+}
+
+
+/* Opcode: SeekHit P1 P2 P3 * *
+** Synopsis: set P2<=seekHit<=P3
+**
+** Increase or decrease the seekHit value for cursor P1, if necessary,
+** so that it is no less than P2 and no greater than P3.
+**
+** The seekHit integer represents the maximum of terms in an index for which
+** there is known to be at least one match.  If the seekHit value is smaller
+** than the total number of equality terms in an index lookup, then the
+** OP_IfNoHope opcode might run to see if the IN loop can be abandoned
+** early, thus saving work.  This is part of the IN-early-out optimization.
+**
+** P1 must be a valid b-tree cursor.
+*/
+case OP_SeekHit: {           /* ncycle */
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pOp->p3>=pOp->p2 );
+  if( pC->seekHit<pOp->p2 ){
+#ifdef SQLITE_DEBUG
+    if( db->flags&SQLITE_VdbeTrace ){
+      printf("seekHit changes from %d to %d\n", pC->seekHit, pOp->p2);
+    }
+#endif
+    pC->seekHit = pOp->p2;
+  }else if( pC->seekHit>pOp->p3 ){
+#ifdef SQLITE_DEBUG
+    if( db->flags&SQLITE_VdbeTrace ){
+      printf("seekHit changes from %d to %d\n", pC->seekHit, pOp->p3);
+    }
+#endif
+    pC->seekHit = pOp->p3;
+  }
+  break;
+}
+
+/* Opcode: IfNotOpen P1 P2 * * *
+** Synopsis: if( !csr[P1] ) goto P2
+**
+** If cursor P1 is not open or if P1 is set to a NULL row using the
+** OP_NullRow opcode, then jump to instruction P2. Otherwise, fall through.
+*/
+case OP_IfNotOpen: {        /* jump */
+  VdbeCursor *pCur;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pCur = p->apCsr[pOp->p1];
+  VdbeBranchTaken(pCur==0 || pCur->nullRow, 2);
+  if( pCur==0 || pCur->nullRow ){
+    goto jump_to_p2_and_check_for_interrupt;
+  }
+  break;
+}
+
+/* Opcode: Found P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
+**
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** is a prefix of any entry in P1 then a jump is made to P2 and
+** P1 is left pointing at the matching entry.
+**
+** This operation leaves the cursor in a state where it can be
+** advanced in the forward direction.  The Next instruction will work,
+** but not the Prev instruction.
+**
+** See also: NotFound, NoConflict, NotExists. SeekGe
+*/
+/* Opcode: NotFound P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
+**
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** is not the prefix of any entry in P1 then a jump is made to P2.  If P1
+** does contain an entry whose prefix matches the P3/P4 record then control
+** falls through to the next instruction and P1 is left pointing at the
+** matching entry.
+**
+** This operation leaves the cursor in a state where it cannot be
+** advanced in either direction.  In other words, the Next and Prev
+** opcodes do not work after this operation.
+**
+** See also: Found, NotExists, NoConflict, IfNoHope
+*/
+/* Opcode: IfNoHope P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** Register P3 is the first of P4 registers that form an unpacked
+** record.  Cursor P1 is an index btree.  P2 is a jump destination.
+** In other words, the operands to this opcode are the same as the
+** operands to OP_NotFound and OP_IdxGT.
+**
+** This opcode is an optimization attempt only.  If this opcode always
+** falls through, the correct answer is still obtained, but extra work
+** is performed.
+**
+** A value of N in the seekHit flag of cursor P1 means that there exists
+** a key P3:N that will match some record in the index.  We want to know
+** if it is possible for a record P3:P4 to match some record in the
+** index.  If it is not possible, we can skip some work.  So if seekHit
+** is less than P4, attempt to find out if a match is possible by running
+** OP_NotFound.
+**
+** This opcode is used in IN clause processing for a multi-column key.
+** If an IN clause is attached to an element of the key other than the
+** left-most element, and if there are no matches on the most recent
+** seek over the whole key, then it might be that one of the key element
+** to the left is prohibiting a match, and hence there is "no hope" of
+** any match regardless of how many IN clause elements are checked.
+** In such a case, we abandon the IN clause search early, using this
+** opcode.  The opcode name comes from the fact that the
+** jump is taken if there is "no hope" of achieving a match.
+**
+** See also: NotFound, SeekHit
+*/
+/* Opcode: NoConflict P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
+** P4>0 then register P3 is the first of P4 registers that form an unpacked
+** record.
+**
+** Cursor P1 is on an index btree.  If the record identified by P3 and P4
+** contains any NULL value, jump immediately to P2.  If all terms of the
+** record are not-NULL then a check is done to determine if any row in the
+** P1 index btree has a matching key prefix.  If there are no matches, jump
+** immediately to P2.  If there is a match, fall through and leave the P1
+** cursor pointing to the matching row.
+**
+** This opcode is similar to OP_NotFound with the exceptions that the
+** branch is always taken if any part of the search key input is NULL.
+**
+** This operation leaves the cursor in a state where it cannot be
+** advanced in either direction.  In other words, the Next and Prev
+** opcodes do not work after this operation.
+**
+** See also: NotFound, Found, NotExists
+*/
+case OP_IfNoHope: {     /* jump, in3, ncycle */
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+#ifdef SQLITE_DEBUG
+  if( db->flags&SQLITE_VdbeTrace ){
+    printf("seekHit is %d\n", pC->seekHit);
+  }
+#endif
+  if( pC->seekHit>=pOp->p4.i ) break;
+  /* Fall through into OP_NotFound */
+  /* no break */ deliberate_fall_through
+}
+case OP_NoConflict:     /* jump, in3, ncycle */
+case OP_NotFound:       /* jump, in3, ncycle */
+case OP_Found: {        /* jump, in3, ncycle */
+  int alreadyExists;
+  int ii;
+  VdbeCursor *pC;
+  UnpackedRecord *pIdxKey;
+  UnpackedRecord r;
+
+#ifdef SQLITE_TEST
+  if( pOp->opcode!=OP_NoConflict ) sqlite3_found_count++;
+#endif
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p4type==P4_INT32 );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+#ifdef SQLITE_DEBUG
+  pC->seekOp = pOp->opcode;
+#endif
+  r.aMem = &aMem[pOp->p3];
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->uc.pCursor!=0 );
+  assert( pC->isTable==0 );
+  r.nField = (u16)pOp->p4.i;
+  if( r.nField>0 ){
+    /* Key values in an array of registers */
+    r.pKeyInfo = pC->pKeyInfo;
+    r.default_rc = 0;
+#ifdef SQLITE_DEBUG
+    (void)sqlite3FaultSim(50);  /* For use by --counter in TH3 */
+    for(ii=0; ii<r.nField; ii++){
+      assert( memIsValid(&r.aMem[ii]) );
+      assert( (r.aMem[ii].flags & MEM_Zero)==0 || r.aMem[ii].n==0 );
+      if( ii ) REGISTER_TRACE(pOp->p3+ii, &r.aMem[ii]);
+    }
+#endif
+    rc = sqlite3BtreeIndexMoveto(pC->uc.pCursor, &r, &pC->seekResult);
+  }else{
+    /* Composite key generated by OP_MakeRecord */
+    assert( r.aMem->flags & MEM_Blob );
+    assert( pOp->opcode!=OP_NoConflict );
+    rc = ExpandBlob(r.aMem);
+    assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+    if( rc ) goto no_mem;
+    pIdxKey = sqlite3VdbeAllocUnpackedRecord(pC->pKeyInfo);
+    if( pIdxKey==0 ) goto no_mem;
+    sqlite3VdbeRecordUnpack(pC->pKeyInfo, r.aMem->n, r.aMem->z, pIdxKey);
+    pIdxKey->default_rc = 0;
+    rc = sqlite3BtreeIndexMoveto(pC->uc.pCursor, pIdxKey, &pC->seekResult);
+    sqlite3DbFreeNN(db, pIdxKey);
+  }
+  if( rc!=SQLITE_OK ){
+    goto abort_due_to_error;
+  }
+  alreadyExists = (pC->seekResult==0);
+  pC->nullRow = 1-alreadyExists;
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+  if( pOp->opcode==OP_Found ){
+    VdbeBranchTaken(alreadyExists!=0,2);
+    if( alreadyExists ) goto jump_to_p2;
+  }else{
+    if( !alreadyExists ){
+      VdbeBranchTaken(1,2);
+      goto jump_to_p2;
+    }
+    if( pOp->opcode==OP_NoConflict ){
+      /* For the OP_NoConflict opcode, take the jump if any of the
+      ** input fields are NULL, since any key with a NULL will not
+      ** conflict */
+      for(ii=0; ii<r.nField; ii++){
+        if( r.aMem[ii].flags & MEM_Null ){
+          VdbeBranchTaken(1,2);
+          goto jump_to_p2;
+        }
+      }
+    }
+    VdbeBranchTaken(0,2);
+    if( pOp->opcode==OP_IfNoHope ){
+      pC->seekHit = pOp->p4.i;
+    }
+  }
+  break;
+}
+
+/* Opcode: SeekRowid P1 P2 P3 * *
+** Synopsis: intkey=r[P3]
+**
+** P1 is the index of a cursor open on an SQL table btree (with integer
+** keys).  If register P3 does not contain an integer or if P1 does not
+** contain a record with rowid P3 then jump immediately to P2.
+** Or, if P2 is 0, raise an SQLITE_CORRUPT error. If P1 does contain
+** a record with rowid P3 then
+** leave the cursor pointing at that record and fall through to the next
+** instruction.
+**
+** The OP_NotExists opcode performs the same operation, but with OP_NotExists
+** the P3 register must be guaranteed to contain an integer value.  With this
+** opcode, register P3 might not contain an integer.
+**
+** The OP_NotFound opcode performs the same operation on index btrees
+** (with arbitrary multi-value keys).
+**
+** This opcode leaves the cursor in a state where it cannot be advanced
+** in either direction.  In other words, the Next and Prev opcodes will
+** not work following this opcode.
+**
+** See also: Found, NotFound, NoConflict, SeekRowid
+*/
+/* Opcode: NotExists P1 P2 P3 * *
+** Synopsis: intkey=r[P3]
+**
+** P1 is the index of a cursor open on an SQL table btree (with integer
+** keys).  P3 is an integer rowid.  If P1 does not contain a record with
+** rowid P3 then jump immediately to P2.  Or, if P2 is 0, raise an
+** SQLITE_CORRUPT error. If P1 does contain a record with rowid P3 then
+** leave the cursor pointing at that record and fall through to the next
+** instruction.
+**
+** The OP_SeekRowid opcode performs the same operation but also allows the
+** P3 register to contain a non-integer value, in which case the jump is
+** always taken.  This opcode requires that P3 always contain an integer.
+**
+** The OP_NotFound opcode performs the same operation on index btrees
+** (with arbitrary multi-value keys).
+**
+** This opcode leaves the cursor in a state where it cannot be advanced
+** in either direction.  In other words, the Next and Prev opcodes will
+** not work following this opcode.
+**
+** See also: Found, NotFound, NoConflict, SeekRowid
+*/
+case OP_SeekRowid: {        /* jump0, in3, ncycle */
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+  u64 iKey;
+
+  pIn3 = &aMem[pOp->p3];
+  testcase( pIn3->flags & MEM_Int );
+  testcase( pIn3->flags & MEM_IntReal );
+  testcase( pIn3->flags & MEM_Real );
+  testcase( (pIn3->flags & (MEM_Str|MEM_Int))==MEM_Str );
+  if( (pIn3->flags & (MEM_Int|MEM_IntReal))==0 ){
+    /* If pIn3->u.i does not contain an integer, compute iKey as the
+    ** integer value of pIn3.  Jump to P2 if pIn3 cannot be converted
+    ** into an integer without loss of information.  Take care to avoid
+    ** changing the datatype of pIn3, however, as it is used by other
+    ** parts of the prepared statement. */
+    Mem x = pIn3[0];
+    applyAffinity(&x, SQLITE_AFF_NUMERIC, encoding);
+    if( (x.flags & MEM_Int)==0 ) goto jump_to_p2;
+    iKey = x.u.i;
+    goto notExistsWithKey;
+  }
+  /* Fall through into OP_NotExists */
+  /* no break */ deliberate_fall_through
+case OP_NotExists:          /* jump, in3, ncycle */
+  pIn3 = &aMem[pOp->p3];
+  assert( (pIn3->flags & MEM_Int)!=0 || pOp->opcode==OP_SeekRowid );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  iKey = pIn3->u.i;
+notExistsWithKey:
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+#ifdef SQLITE_DEBUG
+  if( pOp->opcode==OP_SeekRowid ) pC->seekOp = OP_SeekRowid;
+#endif
+  assert( pC->isTable );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  pCrsr = pC->uc.pCursor;
+  assert( pCrsr!=0 );
+  res = 0;
+  rc = sqlite3BtreeTableMoveto(pCrsr, iKey, 0, &res);
+  assert( rc==SQLITE_OK || res==0 );
+  pC->movetoTarget = iKey;  /* Used by OP_Delete */
+  pC->nullRow = 0;
+  pC->cacheStatus = CACHE_STALE;
+  pC->deferredMoveto = 0;
+  VdbeBranchTaken(res!=0,2);
+  pC->seekResult = res;
+  if( res!=0 ){
+    assert( rc==SQLITE_OK );
+    if( pOp->p2==0 ){
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      goto jump_to_p2;
+    }
+  }
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: Sequence P1 P2 * * *
+** Synopsis: r[P2]=cursor[P1].ctr++
+**
+** Find the next available sequence number for cursor P1.
+** Write the sequence number into register P2.
+** The sequence number on the cursor is incremented after this
+** instruction.
+*/
+case OP_Sequence: {           /* out2 */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( p->apCsr[pOp->p1]!=0 );
+  assert( p->apCsr[pOp->p1]->eCurType!=CURTYPE_VTAB );
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = p->apCsr[pOp->p1]->seqCount++;
+  break;
+}
+
+
+/* Opcode: NewRowid P1 P2 P3 * *
+** Synopsis: r[P2]=rowid
+**
+** Get a new integer record number (a.k.a "rowid") used as the key to a table.
+** The record number is not previously used as a key in the database
+** table that cursor P1 points to.  The new record number is written
+** written to register P2.
+**
+** If P3>0 then P3 is a register in the root frame of this VDBE that holds
+** the largest previously generated record number. No new record numbers are
+** allowed to be less than this value. When this value reaches its maximum,
+** an SQLITE_FULL error is generated. The P3 register is updated with the '
+** generated record number. This P3 mechanism is used to help implement the
+** AUTOINCREMENT feature.
+*/
+case OP_NewRowid: {           /* out2 */
+  i64 v;                 /* The new rowid */
+  VdbeCursor *pC;        /* Cursor of table to get the new rowid */
+  int res;               /* Result of an sqlite3BtreeLast() */
+  int cnt;               /* Counter to limit the number of searches */
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+  Mem *pMem;             /* Register holding largest rowid for AUTOINCREMENT */
+  VdbeFrame *pFrame;     /* Root frame of VDBE */
+#endif
+
+  v = 0;
+  res = 0;
+  pOut = out2Prerelease(p, pOp);
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->isTable );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->uc.pCursor!=0 );
+  {
+    /* The next rowid or record number (different terms for the same
+    ** thing) is obtained in a two-step algorithm.
+    **
+    ** First we attempt to find the largest existing rowid and add one
+    ** to that.  But if the largest existing rowid is already the maximum
+    ** positive integer, we have to fall through to the second
+    ** probabilistic algorithm
+    **
+    ** The second algorithm is to select a rowid at random and see if
+    ** it already exists in the table.  If it does not exist, we have
+    ** succeeded.  If the random rowid does exist, we select a new one
+    ** and try again, up to 100 times.
+    */
+    assert( pC->isTable );
+
+#ifdef SQLITE_32BIT_ROWID
+#   define MAX_ROWID 0x7fffffff
+#else
+    /* Some compilers complain about constants of the form 0x7fffffffffffffff.
+    ** Others complain about 0x7ffffffffffffffffLL.  The following macro seems
+    ** to provide the constant while making all compilers happy.
+    */
+#   define MAX_ROWID  (i64)( (((u64)0x7fffffff)<<32) | (u64)0xffffffff )
+#endif
+
+    if( !pC->useRandomRowid ){
+      rc = sqlite3BtreeLast(pC->uc.pCursor, &res);
+      if( rc!=SQLITE_OK ){
+        goto abort_due_to_error;
+      }
+      if( res ){
+        v = 1;   /* IMP: R-61914-48074 */
+      }else{
+        assert( sqlite3BtreeCursorIsValid(pC->uc.pCursor) );
+        v = sqlite3BtreeIntegerKey(pC->uc.pCursor);
+        if( v>=MAX_ROWID ){
+          pC->useRandomRowid = 1;
+        }else{
+          v++;   /* IMP: R-29538-34987 */
+        }
+      }
+    }
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    if( pOp->p3 ){
+      /* Assert that P3 is a valid memory cell. */
+      assert( pOp->p3>0 );
+      if( p->pFrame ){
+        for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
+        /* Assert that P3 is a valid memory cell. */
+        assert( pOp->p3<=pFrame->nMem );
+        pMem = &pFrame->aMem[pOp->p3];
+      }else{
+        /* Assert that P3 is a valid memory cell. */
+        assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
+        pMem = &aMem[pOp->p3];
+        memAboutToChange(p, pMem);
+      }
+      assert( memIsValid(pMem) );
+
+      REGISTER_TRACE(pOp->p3, pMem);
+      sqlite3VdbeMemIntegerify(pMem);
+      assert( (pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
+      if( pMem->u.i==MAX_ROWID || pC->useRandomRowid ){
+        rc = SQLITE_FULL;   /* IMP: R-17817-00630 */
+        goto abort_due_to_error;
+      }
+      if( v<pMem->u.i+1 ){
+        v = pMem->u.i + 1;
+      }
+      pMem->u.i = v;
+    }
+#endif
+    if( pC->useRandomRowid ){
+      /* IMPLEMENTATION-OF: R-07677-41881 If the largest ROWID is equal to the
+      ** largest possible integer (9223372036854775807) then the database
+      ** engine starts picking positive candidate ROWIDs at random until
+      ** it finds one that is not previously used. */
+      assert( pOp->p3==0 );  /* We cannot be in random rowid mode if this is
+                             ** an AUTOINCREMENT table. */
+      cnt = 0;
+      do{
+        sqlite3_randomness(sizeof(v), &v);
+        v &= (MAX_ROWID>>1); v++;  /* Ensure that v is greater than zero */
+      }while(  ((rc = sqlite3BtreeTableMoveto(pC->uc.pCursor, (u64)v,
+                                                 0, &res))==SQLITE_OK)
+            && (res==0)
+            && (++cnt<100));
+      if( rc ) goto abort_due_to_error;
+      if( res==0 ){
+        rc = SQLITE_FULL;   /* IMP: R-38219-53002 */
+        goto abort_due_to_error;
+      }
+      assert( v>0 );  /* EV: R-40812-03570 */
+    }
+    pC->deferredMoveto = 0;
+    pC->cacheStatus = CACHE_STALE;
+  }
+  pOut->u.i = v;
+  break;
+}
+
+/* Opcode: Insert P1 P2 P3 P4 P5
+** Synopsis: intkey=r[P3] data=r[P2]
+**
+** Write an entry into the table of cursor P1.  A new entry is
+** created if it doesn't already exist or the data for an existing
+** entry is overwritten.  The data is the value MEM_Blob stored in register
+** number P2. The key is stored in register P3. The key must
+** be a MEM_Int.
+**
+** If the OPFLAG_NCHANGE flag of P5 is set, then the row change count is
+** incremented (otherwise not).  If the OPFLAG_LASTROWID flag of P5 is set,
+** then rowid is stored for subsequent return by the
+** sqlite3_last_insert_rowid() function (otherwise it is unmodified).
+**
+** If the OPFLAG_USESEEKRESULT flag of P5 is set, the implementation might
+** run faster by avoiding an unnecessary seek on cursor P1.  However,
+** the OPFLAG_USESEEKRESULT flag must only be set if there have been no prior
+** seeks on the cursor or if the most recent seek used a key equal to P3.
+**
+** If the OPFLAG_ISUPDATE flag is set, then this opcode is part of an
+** UPDATE operation.  Otherwise (if the flag is clear) then this opcode
+** is part of an INSERT operation.  The difference is only important to
+** the update hook.
+**
+** Parameter P4 may point to a Table structure, or may be NULL. If it is
+** not NULL, then the update-hook (sqlite3.xUpdateCallback) is invoked
+** following a successful insert.
+**
+** (WARNING/TODO: If P1 is a pseudo-cursor and P2 is dynamically
+** allocated, then ownership of P2 is transferred to the pseudo-cursor
+** and register P2 becomes ephemeral.  If the cursor is changed, the
+** value of register P2 will then change.  Make sure this does not
+** cause any problems.)
+**
+** This instruction only works on tables.  The equivalent instruction
+** for indices is OP_IdxInsert.
+*/
+case OP_Insert: {
+  Mem *pData;       /* MEM cell holding data for the record to be inserted */
+  Mem *pKey;        /* MEM cell holding key  for the record */
+  VdbeCursor *pC;   /* Cursor to table into which insert is written */
+  int seekResult;   /* Result of prior seek or 0 if no USESEEKRESULT flag */
+  const char *zDb;  /* database name - used by the update hook */
+  Table *pTab;      /* Table structure - used by update and pre-update hooks */
+  BtreePayload x;   /* Payload to be inserted */
+
+  pData = &aMem[pOp->p2];
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( memIsValid(pData) );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->deferredMoveto==0 );
+  assert( pC->uc.pCursor!=0 );
+  assert( (pOp->p5 & OPFLAG_ISNOOP) || pC->isTable );
+  assert( pOp->p4type==P4_TABLE || pOp->p4type>=P4_STATIC );
+  REGISTER_TRACE(pOp->p2, pData);
+  sqlite3VdbeIncrWriteCounter(p, pC);
+
+  pKey = &aMem[pOp->p3];
+  assert( pKey->flags & MEM_Int );
+  assert( memIsValid(pKey) );
+  REGISTER_TRACE(pOp->p3, pKey);
+  x.nKey = pKey->u.i;
+
+  if( pOp->p4type==P4_TABLE && HAS_UPDATE_HOOK(db) ){
+    assert( pC->iDb>=0 );
+    zDb = db->aDb[pC->iDb].zDbSName;
+    pTab = pOp->p4.pTab;
+    assert( (pOp->p5 & OPFLAG_ISNOOP) || HasRowid(pTab) );
+  }else{
+    pTab = 0;
+    zDb = 0;
+  }
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  /* Invoke the pre-update hook, if any */
+  if( pTab ){
+    if( db->xPreUpdateCallback && !(pOp->p5 & OPFLAG_ISUPDATE) ){
+      sqlite3VdbePreUpdateHook(p,pC,SQLITE_INSERT,zDb,pTab,x.nKey,pOp->p2,-1);
+    }
+    if( db->xUpdateCallback==0 || pTab->aCol==0 ){
+      /* Prevent post-update hook from running in cases when it should not */
+      pTab = 0;
+    }
+  }
+  if( pOp->p5 & OPFLAG_ISNOOP ) break;
+#endif
+
+  assert( (pOp->p5 & OPFLAG_LASTROWID)==0 || (pOp->p5 & OPFLAG_NCHANGE)!=0 );
+  if( pOp->p5 & OPFLAG_NCHANGE ){
+    p->nChange++;
+    if( pOp->p5 & OPFLAG_LASTROWID ) db->lastRowid = x.nKey;
+  }
+  assert( (pData->flags & (MEM_Blob|MEM_Str))!=0 || pData->n==0 );
+  x.pData = pData->z;
+  x.nData = pData->n;
+  seekResult = ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0);
+  if( pData->flags & MEM_Zero ){
+    x.nZero = pData->u.nZero;
+  }else{
+    x.nZero = 0;
+  }
+  x.pKey = 0;
+  assert( BTREE_PREFORMAT==OPFLAG_PREFORMAT );
+  rc = sqlite3BtreeInsert(pC->uc.pCursor, &x,
+      (pOp->p5 & (OPFLAG_APPEND|OPFLAG_SAVEPOSITION|OPFLAG_PREFORMAT)),
+      seekResult
+  );
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+  colCacheCtr++;
+
+  /* Invoke the update-hook if required. */
+  if( rc ) goto abort_due_to_error;
+  if( pTab ){
+    assert( db->xUpdateCallback!=0 );
+    assert( pTab->aCol!=0 );
+    db->xUpdateCallback(db->pUpdateArg,
+           (pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT,
+           zDb, pTab->zName, x.nKey);
+  }
+  break;
+}
+
+/* Opcode: RowCell P1 P2 P3 * *
+**
+** P1 and P2 are both open cursors. Both must be opened on the same type
+** of table - intkey or index. This opcode is used as part of copying
+** the current row from P2 into P1. If the cursors are opened on intkey
+** tables, register P3 contains the rowid to use with the new record in
+** P1. If they are opened on index tables, P3 is not used.
+**
+** This opcode must be followed by either an Insert or InsertIdx opcode
+** with the OPFLAG_PREFORMAT flag set to complete the insert operation.
+*/
+case OP_RowCell: {
+  VdbeCursor *pDest;              /* Cursor to write to */
+  VdbeCursor *pSrc;               /* Cursor to read from */
+  i64 iKey;                       /* Rowid value to insert with */
+  assert( pOp[1].opcode==OP_Insert || pOp[1].opcode==OP_IdxInsert );
+  assert( pOp[1].opcode==OP_Insert    || pOp->p3==0 );
+  assert( pOp[1].opcode==OP_IdxInsert || pOp->p3>0 );
+  assert( pOp[1].p5 & OPFLAG_PREFORMAT );
+  pDest = p->apCsr[pOp->p1];
+  pSrc = p->apCsr[pOp->p2];
+  iKey = pOp->p3 ? aMem[pOp->p3].u.i : 0;
+  rc = sqlite3BtreeTransferRow(pDest->uc.pCursor, pSrc->uc.pCursor, iKey);
+  if( rc!=SQLITE_OK ) goto abort_due_to_error;
+  break;
+};
+
+/* Opcode: Delete P1 P2 P3 P4 P5
+**
+** Delete the record at which the P1 cursor is currently pointing.
+**
+** If the OPFLAG_SAVEPOSITION bit of the P5 parameter is set, then
+** the cursor will be left pointing at  either the next or the previous
+** record in the table. If it is left pointing at the next record, then
+** the next Next instruction will be a no-op. As a result, in this case
+** it is ok to delete a record from within a Next loop. If
+** OPFLAG_SAVEPOSITION bit of P5 is clear, then the cursor will be
+** left in an undefined state.
+**
+** If the OPFLAG_AUXDELETE bit is set on P5, that indicates that this
+** delete is one of several associated with deleting a table row and
+** all its associated index entries.  Exactly one of those deletes is
+** the "primary" delete.  The others are all on OPFLAG_FORDELETE
+** cursors or else are marked with the AUXDELETE flag.
+**
+** If the OPFLAG_NCHANGE (0x01) flag of P2 (NB: P2 not P5) is set, then
+** the row change count is incremented (otherwise not).
+**
+** If the OPFLAG_ISNOOP (0x40) flag of P2 (not P5!) is set, then the
+** pre-update-hook for deletes is run, but the btree is otherwise unchanged.
+** This happens when the OP_Delete is to be shortly followed by an OP_Insert
+** with the same key, causing the btree entry to be overwritten.
+**
+** P1 must not be pseudo-table.  It has to be a real table with
+** multiple rows.
+**
+** If P4 is not NULL then it points to a Table object. In this case either
+** the update or pre-update hook, or both, may be invoked. The P1 cursor must
+** have been positioned using OP_NotFound prior to invoking this opcode in
+** this case. Specifically, if one is configured, the pre-update hook is
+** invoked if P4 is not NULL. The update-hook is invoked if one is configured,
+** P4 is not NULL, and the OPFLAG_NCHANGE flag is set in P2.
+**
+** If the OPFLAG_ISUPDATE flag is set in P2, then P3 contains the address
+** of the memory cell that contains the value that the rowid of the row will
+** be set to by the update.
+*/
+case OP_Delete: {
+  VdbeCursor *pC;
+  const char *zDb;
+  Table *pTab;
+  int opflags;
+
+  opflags = pOp->p2;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->uc.pCursor!=0 );
+  assert( pC->deferredMoveto==0 );
+  sqlite3VdbeIncrWriteCounter(p, pC);
+
+#ifdef SQLITE_DEBUG
+  if( pOp->p4type==P4_TABLE
+   && HasRowid(pOp->p4.pTab)
+   && pOp->p5==0
+   && sqlite3BtreeCursorIsValidNN(pC->uc.pCursor)
+  ){
+    /* If p5 is zero, the seek operation that positioned the cursor prior to
+    ** OP_Delete will have also set the pC->movetoTarget field to the rowid of
+    ** the row that is being deleted */
+    i64 iKey = sqlite3BtreeIntegerKey(pC->uc.pCursor);
+    assert( CORRUPT_DB || pC->movetoTarget==iKey );
+  }
+#endif
+
+  /* If the update-hook or pre-update-hook will be invoked, set zDb to
+  ** the name of the db to pass as to it. Also set local pTab to a copy
+  ** of p4.pTab. Finally, if p5 is true, indicating that this cursor was
+  ** last moved with OP_Next or OP_Prev, not Seek or NotFound, set
+  ** VdbeCursor.movetoTarget to the current rowid.  */
+  if( pOp->p4type==P4_TABLE && HAS_UPDATE_HOOK(db) ){
+    assert( pC->iDb>=0 );
+    assert( pOp->p4.pTab!=0 );
+    zDb = db->aDb[pC->iDb].zDbSName;
+    pTab = pOp->p4.pTab;
+    if( (pOp->p5 & OPFLAG_SAVEPOSITION)!=0 && pC->isTable ){
+      pC->movetoTarget = sqlite3BtreeIntegerKey(pC->uc.pCursor);
+    }
+  }else{
+    zDb = 0;
+    pTab = 0;
+  }
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  /* Invoke the pre-update-hook if required. */
+  assert( db->xPreUpdateCallback==0 || pTab==pOp->p4.pTab );
+  if( db->xPreUpdateCallback && pTab ){
+    assert( !(opflags & OPFLAG_ISUPDATE)
+         || HasRowid(pTab)==0
+         || (aMem[pOp->p3].flags & MEM_Int)
+    );
+    sqlite3VdbePreUpdateHook(p, pC,
+        (opflags & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_DELETE,
+        zDb, pTab, pC->movetoTarget,
+        pOp->p3, -1
+    );
+  }
+  if( opflags & OPFLAG_ISNOOP ) break;
+#endif
+
+  /* Only flags that can be set are SAVEPOISTION and AUXDELETE */
+  assert( (pOp->p5 & ~(OPFLAG_SAVEPOSITION|OPFLAG_AUXDELETE))==0 );
+  assert( OPFLAG_SAVEPOSITION==BTREE_SAVEPOSITION );
+  assert( OPFLAG_AUXDELETE==BTREE_AUXDELETE );
+
+#ifdef SQLITE_DEBUG
+  if( p->pFrame==0 ){
+    if( pC->isEphemeral==0
+        && (pOp->p5 & OPFLAG_AUXDELETE)==0
+        && (pC->wrFlag & OPFLAG_FORDELETE)==0
+      ){
+      nExtraDelete++;
+    }
+    if( pOp->p2 & OPFLAG_NCHANGE ){
+      nExtraDelete--;
+    }
+  }
+#endif
+
+  rc = sqlite3BtreeDelete(pC->uc.pCursor, pOp->p5);
+  pC->cacheStatus = CACHE_STALE;
+  colCacheCtr++;
+  pC->seekResult = 0;
+  if( rc ) goto abort_due_to_error;
+
+  /* Invoke the update-hook if required. */
+  if( opflags & OPFLAG_NCHANGE ){
+    p->nChange++;
+    if( db->xUpdateCallback && ALWAYS(pTab!=0) && HasRowid(pTab) ){
+      db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, pTab->zName,
+          pC->movetoTarget);
+      assert( pC->iDb>=0 );
+    }
+  }
+
+  break;
+}
+/* Opcode: ResetCount * * * * *
+**
+** The value of the change counter is copied to the database handle
+** change counter (returned by subsequent calls to sqlite3_changes()).
+** Then the VMs internal change counter resets to 0.
+** This is used by trigger programs.
+*/
+case OP_ResetCount: {
+  sqlite3VdbeSetChanges(db, p->nChange);
+  p->nChange = 0;
+  break;
+}
+
+/* Opcode: SorterCompare P1 P2 P3 P4
+** Synopsis: if key(P1)!=trim(r[P3],P4) goto P2
+**
+** P1 is a sorter cursor. This instruction compares a prefix of the
+** record blob in register P3 against a prefix of the entry that
+** the sorter cursor currently points to.  Only the first P4 fields
+** of r[P3] and the sorter record are compared.
+**
+** If either P3 or the sorter contains a NULL in one of their significant
+** fields (not counting the P4 fields at the end which are ignored) then
+** the comparison is assumed to be equal.
+**
+** Fall through to next instruction if the two records compare equal to
+** each other.  Jump to P2 if they are different.
+*/
+case OP_SorterCompare: {
+  VdbeCursor *pC;
+  int res;
+  int nKeyCol;
+
+  pC = p->apCsr[pOp->p1];
+  assert( isSorter(pC) );
+  assert( pOp->p4type==P4_INT32 );
+  pIn3 = &aMem[pOp->p3];
+  nKeyCol = pOp->p4.i;
+  res = 0;
+  rc = sqlite3VdbeSorterCompare(pC, pIn3, nKeyCol, &res);
+  VdbeBranchTaken(res!=0,2);
+  if( rc ) goto abort_due_to_error;
+  if( res ) goto jump_to_p2;
+  break;
+};
+
+/* Opcode: SorterData P1 P2 P3 * *
+** Synopsis: r[P2]=data
+**
+** Write into register P2 the current sorter data for sorter cursor P1.
+** Then clear the column header cache on cursor P3.
+**
+** This opcode is normally used to move a record out of the sorter and into
+** a register that is the source for a pseudo-table cursor created using
+** OpenPseudo.  That pseudo-table cursor is the one that is identified by
+** parameter P3.  Clearing the P3 column cache as part of this opcode saves
+** us from having to issue a separate NullRow instruction to clear that cache.
+*/
+case OP_SorterData: {       /* ncycle */
+  VdbeCursor *pC;
+
+  pOut = &aMem[pOp->p2];
+  pC = p->apCsr[pOp->p1];
+  assert( isSorter(pC) );
+  rc = sqlite3VdbeSorterRowkey(pC, pOut);
+  assert( rc!=SQLITE_OK || (pOut->flags & MEM_Blob) );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  if( rc ) goto abort_due_to_error;
+  p->apCsr[pOp->p3]->cacheStatus = CACHE_STALE;
+  break;
+}
+
+/* Opcode: RowData P1 P2 P3 * *
+** Synopsis: r[P2]=data
+**
+** Write into register P2 the complete row content for the row at
+** which cursor P1 is currently pointing.
+** There is no interpretation of the data.
+** It is just copied onto the P2 register exactly as
+** it is found in the database file.
+**
+** If cursor P1 is an index, then the content is the key of the row.
+** If cursor P2 is a table, then the content extracted is the data.
+**
+** If the P1 cursor must be pointing to a valid row (not a NULL row)
+** of a real table, not a pseudo-table.
+**
+** If P3!=0 then this opcode is allowed to make an ephemeral pointer
+** into the database page.  That means that the content of the output
+** register will be invalidated as soon as the cursor moves - including
+** moves caused by other cursors that "save" the current cursors
+** position in order that they can write to the same table.  If P3==0
+** then a copy of the data is made into memory.  P3!=0 is faster, but
+** P3==0 is safer.
+**
+** If P3!=0 then the content of the P2 register is unsuitable for use
+** in OP_Result and any OP_Result will invalidate the P2 register content.
+** The P2 register content is invalidated by opcodes like OP_Function or
+** by any use of another cursor pointing to the same table.
+*/
+case OP_RowData: {
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  u32 n;
+
+  pOut = out2Prerelease(p, pOp);
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( isSorter(pC)==0 );
+  assert( pC->nullRow==0 );
+  assert( pC->uc.pCursor!=0 );
+  pCrsr = pC->uc.pCursor;
+
+  /* The OP_RowData opcodes always follow OP_NotExists or
+  ** OP_SeekRowid or OP_Rewind/Op_Next with no intervening instructions
+  ** that might invalidate the cursor.
+  ** If this where not the case, on of the following assert()s
+  ** would fail.  Should this ever change (because of changes in the code
+  ** generator) then the fix would be to insert a call to
+  ** sqlite3VdbeCursorMoveto().
+  */
+  assert( pC->deferredMoveto==0 );
+  assert( sqlite3BtreeCursorIsValid(pCrsr) );
+
+  n = sqlite3BtreePayloadSize(pCrsr);
+  if( n>(u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
+  }
+  testcase( n==0 );
+  rc = sqlite3VdbeMemFromBtreeZeroOffset(pCrsr, n, pOut);
+  if( rc ) goto abort_due_to_error;
+  if( !pOp->p3 ) Deephemeralize(pOut);
+  UPDATE_MAX_BLOBSIZE(pOut);
+  REGISTER_TRACE(pOp->p2, pOut);
+  break;
+}
+
+/* Opcode: Rowid P1 P2 * * *
+** Synopsis: r[P2]=PX rowid of P1
+**
+** Store in register P2 an integer which is the key of the table entry that
+** P1 is currently point to.
+**
+** P1 can be either an ordinary table or a virtual table.  There used to
+** be a separate OP_VRowid opcode for use with virtual tables, but this
+** one opcode now works for both table types.
+*/
+case OP_Rowid: {                 /* out2, ncycle */
+  VdbeCursor *pC;
+  i64 v;
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+
+  pOut = out2Prerelease(p, pOp);
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType!=CURTYPE_PSEUDO || pC->nullRow );
+  if( pC->nullRow ){
+    pOut->flags = MEM_Null;
+    break;
+  }else if( pC->deferredMoveto ){
+    v = pC->movetoTarget;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  }else if( pC->eCurType==CURTYPE_VTAB ){
+    assert( pC->uc.pVCur!=0 );
+    pVtab = pC->uc.pVCur->pVtab;
+    pModule = pVtab->pModule;
+    assert( pModule->xRowid );
+    rc = pModule->xRowid(pC->uc.pVCur, &v);
+    sqlite3VtabImportErrmsg(p, pVtab);
+    if( rc ) goto abort_due_to_error;
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+  }else{
+    assert( pC->eCurType==CURTYPE_BTREE );
+    assert( pC->uc.pCursor!=0 );
+    rc = sqlite3VdbeCursorRestore(pC);
+    if( rc ) goto abort_due_to_error;
+    if( pC->nullRow ){
+      pOut->flags = MEM_Null;
+      break;
+    }
+    v = sqlite3BtreeIntegerKey(pC->uc.pCursor);
+  }
+  pOut->u.i = v;
+  break;
+}
+
+/* Opcode: NullRow P1 * * * *
+**
+** Move the cursor P1 to a null row.  Any OP_Column operations
+** that occur while the cursor is on the null row will always
+** write a NULL.
+**
+** If cursor P1 is not previously opened, open it now to a special
+** pseudo-cursor that always returns NULL for every column.
+*/
+case OP_NullRow: {
+  VdbeCursor *pC;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  if( pC==0 ){
+    /* If the cursor is not already open, create a special kind of
+    ** pseudo-cursor that always gives null rows. */
+    pC = allocateCursor(p, pOp->p1, 1, CURTYPE_PSEUDO);
+    if( pC==0 ) goto no_mem;
+    pC->seekResult = 0;
+    pC->isTable = 1;
+    pC->noReuse = 1;
+    pC->uc.pCursor = sqlite3BtreeFakeValidCursor();
+  }
+  pC->nullRow = 1;
+  pC->cacheStatus = CACHE_STALE;
+  if( pC->eCurType==CURTYPE_BTREE ){
+    assert( pC->uc.pCursor!=0 );
+    sqlite3BtreeClearCursor(pC->uc.pCursor);
+  }
+#ifdef SQLITE_DEBUG
+  if( pC->seekOp==0 ) pC->seekOp = OP_NullRow;
+#endif
+  break;
+}
+
+/* Opcode: SeekEnd P1 * * * *
+**
+** Position cursor P1 at the end of the btree for the purpose of
+** appending a new entry onto the btree.
+**
+** It is assumed that the cursor is used only for appending and so
+** if the cursor is valid, then the cursor must already be pointing
+** at the end of the btree and so no changes are made to
+** the cursor.
+*/
+/* Opcode: Last P1 P2 * * *
+**
+** The next use of the Rowid or Column or Prev instruction for P1
+** will refer to the last entry in the database table or index.
+** If the table or index is empty and P2>0, then jump immediately to P2.
+** If P2 is 0 or if the table or index is not empty, fall through
+** to the following instruction.
+**
+** This opcode leaves the cursor configured to move in reverse order,
+** from the end toward the beginning.  In other words, the cursor is
+** configured to use Prev, not Next.
+*/
+case OP_SeekEnd:             /* ncycle */
+case OP_Last: {              /* jump0, ncycle */
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  pCrsr = pC->uc.pCursor;
+  res = 0;
+  assert( pCrsr!=0 );
+#ifdef SQLITE_DEBUG
+  pC->seekOp = pOp->opcode;
+#endif
+  if( pOp->opcode==OP_SeekEnd ){
+    assert( pOp->p2==0 );
+    pC->seekResult = -1;
+    if( sqlite3BtreeCursorIsValidNN(pCrsr) ){
+      break;
+    }
+  }
+  rc = sqlite3BtreeLast(pCrsr, &res);
+  pC->nullRow = (u8)res;
+  pC->deferredMoveto = 0;
+  pC->cacheStatus = CACHE_STALE;
+  if( rc ) goto abort_due_to_error;
+  if( pOp->p2>0 ){
+    VdbeBranchTaken(res!=0,2);
+    if( res ) goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: IfSizeBetween P1 P2 P3 P4 *
+**
+** Let N be the approximate number of rows in the table or index
+** with cursor P1 and let X be 10*log2(N) if N is positive or -1
+** if N is zero.
+**
+** Jump to P2 if X is in between P3 and P4, inclusive.
+*/
+case OP_IfSizeBetween: {        /* jump */
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+  i64 sz;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p4type==P4_INT32 );
+  assert( pOp->p3>=-1 && pOp->p3<=640*2 );
+  assert( pOp->p4.i>=-1 && pOp->p4.i<=640*2 );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  pCrsr = pC->uc.pCursor;
+  assert( pCrsr );
+  rc = sqlite3BtreeFirst(pCrsr, &res);
+  if( rc ) goto abort_due_to_error;
+  if( res!=0 ){
+    sz = -1;  /* -Infinity encoding */
+  }else{
+    sz = sqlite3BtreeRowCountEst(pCrsr);
+    assert( sz>0 );
+    sz = sqlite3LogEst((u64)sz);
+  }
+  res = sz>=pOp->p3 && sz<=pOp->p4.i;
+  VdbeBranchTaken(res!=0,2);
+  if( res ) goto jump_to_p2;
+  break;
+}
+
+
+/* Opcode: SorterSort P1 P2 * * *
+**
+** After all records have been inserted into the Sorter object
+** identified by P1, invoke this opcode to actually do the sorting.
+** Jump to P2 if there are no records to be sorted.
+**
+** This opcode is an alias for OP_Sort and OP_Rewind that is used
+** for Sorter objects.
+*/
+/* Opcode: Sort P1 P2 * * *
+**
+** This opcode does exactly the same thing as OP_Rewind except that
+** it increments an undocumented global variable used for testing.
+**
+** Sorting is accomplished by writing records into a sorting index,
+** then rewinding that index and playing it back from beginning to
+** end.  We use the OP_Sort opcode instead of OP_Rewind to do the
+** rewinding so that the global variable will be incremented and
+** regression tests can determine whether or not the optimizer is
+** correctly optimizing out sorts.
+*/
+case OP_SorterSort:    /* jump ncycle */
+case OP_Sort: {        /* jump ncycle */
+#ifdef SQLITE_TEST
+  sqlite3_sort_count++;
+  sqlite3_search_count--;
+#endif
+  p->aCounter[SQLITE_STMTSTATUS_SORT]++;
+  /* Fall through into OP_Rewind */
+  /* no break */ deliberate_fall_through
+}
+/* Opcode: Rewind P1 P2 * * *
+**
+** The next use of the Rowid or Column or Next instruction for P1
+** will refer to the first entry in the database table or index.
+** If the table or index is empty, jump immediately to P2.
+** If the table or index is not empty, fall through to the following
+** instruction.
+**
+** If P2 is zero, that is an assertion that the P1 table is never
+** empty and hence the jump will never be taken.
+**
+** This opcode leaves the cursor configured to move in forward order,
+** from the beginning toward the end.  In other words, the cursor is
+** configured to use Next, not Prev.
+*/
+case OP_Rewind: {        /* jump0, ncycle */
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p5==0 );
+  assert( pOp->p2>=0 && pOp->p2<p->nOp );
+
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( isSorter(pC)==(pOp->opcode==OP_SorterSort) );
+  res = 1;
+#ifdef SQLITE_DEBUG
+  pC->seekOp = OP_Rewind;
+#endif
+  if( isSorter(pC) ){
+    rc = sqlite3VdbeSorterRewind(pC, &res);
+  }else{
+    assert( pC->eCurType==CURTYPE_BTREE );
+    pCrsr = pC->uc.pCursor;
+    assert( pCrsr );
+    rc = sqlite3BtreeFirst(pCrsr, &res);
+    pC->deferredMoveto = 0;
+    pC->cacheStatus = CACHE_STALE;
+  }
+  if( rc ) goto abort_due_to_error;
+  pC->nullRow = (u8)res;
+  if( pOp->p2>0 ){
+    VdbeBranchTaken(res!=0,2);
+    if( res ) goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: Next P1 P2 P3 * P5
+**
+** Advance cursor P1 so that it points to the next key/data pair in its
+** table or index.  If there are no more key/value pairs then fall through
+** to the following instruction.  But if the cursor advance was successful,
+** jump immediately to P2.
+**
+** The Next opcode is only valid following an SeekGT, SeekGE, or
+** OP_Rewind opcode used to position the cursor.  Next is not allowed
+** to follow SeekLT, SeekLE, or OP_Last.
+**
+** The P1 cursor must be for a real table, not a pseudo-table.  P1 must have
+** been opened prior to this opcode or the program will segfault.
+**
+** The P3 value is a hint to the btree implementation. If P3==1, that
+** means P1 is an SQL index and that this instruction could have been
+** omitted if that index had been unique.  P3 is usually 0.  P3 is
+** always either 0 or 1.
+**
+** If P5 is positive and the jump is taken, then event counter
+** number P5-1 in the prepared statement is incremented.
+**
+** See also: Prev
+*/
+/* Opcode: Prev P1 P2 P3 * P5
+**
+** Back up cursor P1 so that it points to the previous key/data pair in its
+** table or index.  If there is no previous key/value pairs then fall through
+** to the following instruction.  But if the cursor backup was successful,
+** jump immediately to P2.
+**
+**
+** The Prev opcode is only valid following an SeekLT, SeekLE, or
+** OP_Last opcode used to position the cursor.  Prev is not allowed
+** to follow SeekGT, SeekGE, or OP_Rewind.
+**
+** The P1 cursor must be for a real table, not a pseudo-table.  If P1 is
+** not open then the behavior is undefined.
+**
+** The P3 value is a hint to the btree implementation. If P3==1, that
+** means P1 is an SQL index and that this instruction could have been
+** omitted if that index had been unique.  P3 is usually 0.  P3 is
+** always either 0 or 1.
+**
+** If P5 is positive and the jump is taken, then event counter
+** number P5-1 in the prepared statement is incremented.
+*/
+/* Opcode: SorterNext P1 P2 * * P5
+**
+** This opcode works just like OP_Next except that P1 must be a
+** sorter object for which the OP_SorterSort opcode has been
+** invoked.  This opcode advances the cursor to the next sorted
+** record, or jumps to P2 if there are no more sorted records.
+*/
+case OP_SorterNext: {  /* jump */
+  VdbeCursor *pC;
+
+  pC = p->apCsr[pOp->p1];
+  assert( isSorter(pC) );
+  rc = sqlite3VdbeSorterNext(db, pC);
+  goto next_tail;
+
+case OP_Prev:          /* jump, ncycle */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p5==0
+       || pOp->p5==SQLITE_STMTSTATUS_FULLSCAN_STEP
+       || pOp->p5==SQLITE_STMTSTATUS_AUTOINDEX);
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->deferredMoveto==0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->seekOp==OP_SeekLT || pC->seekOp==OP_SeekLE
+       || pC->seekOp==OP_Last   || pC->seekOp==OP_IfNoHope
+       || pC->seekOp==OP_NullRow);
+  rc = sqlite3BtreePrevious(pC->uc.pCursor, pOp->p3);
+  goto next_tail;
+
+case OP_Next:          /* jump, ncycle */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p5==0
+       || pOp->p5==SQLITE_STMTSTATUS_FULLSCAN_STEP
+       || pOp->p5==SQLITE_STMTSTATUS_AUTOINDEX);
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->deferredMoveto==0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->seekOp==OP_SeekGT || pC->seekOp==OP_SeekGE
+       || pC->seekOp==OP_Rewind || pC->seekOp==OP_Found
+       || pC->seekOp==OP_NullRow|| pC->seekOp==OP_SeekRowid
+       || pC->seekOp==OP_IfNoHope);
+  rc = sqlite3BtreeNext(pC->uc.pCursor, pOp->p3);
+
+next_tail:
+  pC->cacheStatus = CACHE_STALE;
+  VdbeBranchTaken(rc==SQLITE_OK,2);
+  if( rc==SQLITE_OK ){
+    pC->nullRow = 0;
+    p->aCounter[pOp->p5]++;
+#ifdef SQLITE_TEST
+    sqlite3_search_count++;
+#endif
+    goto jump_to_p2_and_check_for_interrupt;
+  }
+  if( rc!=SQLITE_DONE ) goto abort_due_to_error;
+  rc = SQLITE_OK;
+  pC->nullRow = 1;
+  goto check_for_interrupt;
+}
+
+/* Opcode: IdxInsert P1 P2 P3 P4 P5
+** Synopsis: key=r[P2]
+**
+** Register P2 holds an SQL index key made using the
+** MakeRecord instructions.  This opcode writes that key
+** into the index P1.  Data for the entry is nil.
+**
+** If P4 is not zero, then it is the number of values in the unpacked
+** key of reg(P2).  In that case, P3 is the index of the first register
+** for the unpacked key.  The availability of the unpacked key can sometimes
+** be an optimization.
+**
+** If P5 has the OPFLAG_APPEND bit set, that is a hint to the b-tree layer
+** that this insert is likely to be an append.
+**
+** If P5 has the OPFLAG_NCHANGE bit set, then the change counter is
+** incremented by this instruction.  If the OPFLAG_NCHANGE bit is clear,
+** then the change counter is unchanged.
+**
+** If the OPFLAG_USESEEKRESULT flag of P5 is set, the implementation might
+** run faster by avoiding an unnecessary seek on cursor P1.  However,
+** the OPFLAG_USESEEKRESULT flag must only be set if there have been no prior
+** seeks on the cursor or if the most recent seek used a key equivalent
+** to P2.
+**
+** This instruction only works for indices.  The equivalent instruction
+** for tables is OP_Insert.
+*/
+case OP_IdxInsert: {        /* in2 */
+  VdbeCursor *pC;
+  BtreePayload x;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  sqlite3VdbeIncrWriteCounter(p, pC);
+  assert( pC!=0 );
+  assert( !isSorter(pC) );
+  pIn2 = &aMem[pOp->p2];
+  assert( (pIn2->flags & MEM_Blob) || (pOp->p5 & OPFLAG_PREFORMAT) );
+  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->isTable==0 );
+  rc = ExpandBlob(pIn2);
+  if( rc ) goto abort_due_to_error;
+  x.nKey = pIn2->n;
+  x.pKey = pIn2->z;
+  x.aMem = aMem + pOp->p3;
+  x.nMem = (u16)pOp->p4.i;
+  rc = sqlite3BtreeInsert(pC->uc.pCursor, &x,
+       (pOp->p5 & (OPFLAG_APPEND|OPFLAG_SAVEPOSITION|OPFLAG_PREFORMAT)),
+      ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
+      );
+  assert( pC->deferredMoveto==0 );
+  pC->cacheStatus = CACHE_STALE;
+  if( rc) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: SorterInsert P1 P2 * * *
+** Synopsis: key=r[P2]
+**
+** Register P2 holds an SQL index key made using the
+** MakeRecord instructions.  This opcode writes that key
+** into the sorter P1.  Data for the entry is nil.
+*/
+case OP_SorterInsert: {     /* in2 */
+  VdbeCursor *pC;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  sqlite3VdbeIncrWriteCounter(p, pC);
+  assert( pC!=0 );
+  assert( isSorter(pC) );
+  pIn2 = &aMem[pOp->p2];
+  assert( pIn2->flags & MEM_Blob );
+  assert( pC->isTable==0 );
+  rc = ExpandBlob(pIn2);
+  if( rc ) goto abort_due_to_error;
+  rc = sqlite3VdbeSorterWrite(pC, pIn2);
+  if( rc) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: IdxDelete P1 P2 P3 * P5
+** Synopsis: key=r[P2@P3]
+**
+** The content of P3 registers starting at register P2 form
+** an unpacked index key. This opcode removes that entry from the
+** index opened by cursor P1.
+**
+** If P5 is not zero, then raise an SQLITE_CORRUPT_INDEX error
+** if no matching index entry is found.  This happens when running
+** an UPDATE or DELETE statement and the index entry to be updated
+** or deleted is not found.  For some uses of IdxDelete
+** (example:  the EXCEPT operator) it does not matter that no matching
+** entry is found.  For those cases, P5 is zero.  Also, do not raise
+** this (self-correcting and non-critical) error if in writable_schema mode.
+*/
+case OP_IdxDelete: {
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int res;
+  UnpackedRecord r;
+
+  assert( pOp->p3>0 );
+  assert( pOp->p2>0 && pOp->p2+pOp->p3<=(p->nMem+1 - p->nCursor)+1 );
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  sqlite3VdbeIncrWriteCounter(p, pC);
+  pCrsr = pC->uc.pCursor;
+  assert( pCrsr!=0 );
+  r.pKeyInfo = pC->pKeyInfo;
+  r.nField = (u16)pOp->p3;
+  r.default_rc = 0;
+  r.aMem = &aMem[pOp->p2];
+  rc = sqlite3BtreeIndexMoveto(pCrsr, &r, &res);
+  if( rc ) goto abort_due_to_error;
+  if( res==0 ){
+    rc = sqlite3BtreeDelete(pCrsr, BTREE_AUXDELETE);
+    if( rc ) goto abort_due_to_error;
+  }else if( pOp->p5 && !sqlite3WritableSchema(db) ){
+    rc = sqlite3ReportError(SQLITE_CORRUPT_INDEX, __LINE__, "index corruption");
+    goto abort_due_to_error;
+  }
+  assert( pC->deferredMoveto==0 );
+  pC->cacheStatus = CACHE_STALE;
+  pC->seekResult = 0;
+  break;
+}
+
+/* Opcode: DeferredSeek P1 * P3 P4 *
+** Synopsis: Move P3 to P1.rowid if needed
+**
+** P1 is an open index cursor and P3 is a cursor on the corresponding
+** table.  This opcode does a deferred seek of the P3 table cursor
+** to the row that corresponds to the current row of P1.
+**
+** This is a deferred seek.  Nothing actually happens until
+** the cursor is used to read a record.  That way, if no reads
+** occur, no unnecessary I/O happens.
+**
+** P4 may be an array of integers (type P4_INTARRAY) containing
+** one entry for each column in the P3 table.  If array entry a(i)
+** is non-zero, then reading column a(i)-1 from cursor P3 is
+** equivalent to performing the deferred seek and then reading column i
+** from P1.  This information is stored in P3 and used to redirect
+** reads against P3 over to P1, thus possibly avoiding the need to
+** seek and read cursor P3.
+*/
+/* Opcode: IdxRowid P1 P2 * * *
+** Synopsis: r[P2]=rowid
+**
+** Write into register P2 an integer which is the last entry in the record at
+** the end of the index key pointed to by cursor P1.  This integer should be
+** the rowid of the table entry to which this index entry points.
+**
+** See also: Rowid, MakeRecord.
+*/
+case OP_DeferredSeek:         /* ncycle */
+case OP_IdxRowid: {           /* out2, ncycle */
+  VdbeCursor *pC;             /* The P1 index cursor */
+  VdbeCursor *pTabCur;        /* The P2 table cursor (OP_DeferredSeek only) */
+  i64 rowid;                  /* Rowid that P1 current points to */
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE || IsNullCursor(pC) );
+  assert( pC->uc.pCursor!=0 );
+  assert( pC->isTable==0 || IsNullCursor(pC) );
+  assert( pC->deferredMoveto==0 );
+  assert( !pC->nullRow || pOp->opcode==OP_IdxRowid );
+
+  /* The IdxRowid and Seek opcodes are combined because of the commonality
+  ** of sqlite3VdbeCursorRestore() and sqlite3VdbeIdxRowid(). */
+  rc = sqlite3VdbeCursorRestore(pC);
+
+  /* sqlite3VdbeCursorRestore() may fail if the cursor has been disturbed
+  ** since it was last positioned and an error (e.g. OOM or an IO error)
+  ** occurs while trying to reposition it. */
+  if( rc!=SQLITE_OK ) goto abort_due_to_error;
+
+  if( !pC->nullRow ){
+    rowid = 0;  /* Not needed.  Only used to silence a warning. */
+    rc = sqlite3VdbeIdxRowid(db, pC->uc.pCursor, &rowid);
+    if( rc!=SQLITE_OK ){
+      goto abort_due_to_error;
+    }
+    if( pOp->opcode==OP_DeferredSeek ){
+      assert( pOp->p3>=0 && pOp->p3<p->nCursor );
+      pTabCur = p->apCsr[pOp->p3];
+      assert( pTabCur!=0 );
+      assert( pTabCur->eCurType==CURTYPE_BTREE );
+      assert( pTabCur->uc.pCursor!=0 );
+      assert( pTabCur->isTable );
+      pTabCur->nullRow = 0;
+      pTabCur->movetoTarget = rowid;
+      pTabCur->deferredMoveto = 1;
+      pTabCur->cacheStatus = CACHE_STALE;
+      assert( pOp->p4type==P4_INTARRAY || pOp->p4.ai==0 );
+      assert( !pTabCur->isEphemeral );
+      pTabCur->ub.aAltMap = pOp->p4.ai;
+      assert( !pC->isEphemeral );
+      pTabCur->pAltCursor = pC;
+    }else{
+      pOut = out2Prerelease(p, pOp);
+      pOut->u.i = rowid;
+    }
+  }else{
+    assert( pOp->opcode==OP_IdxRowid );
+    sqlite3VdbeMemSetNull(&aMem[pOp->p2]);
+  }
+  break;
+}
+
+/* Opcode: FinishSeek P1 * * * *
+**
+** If cursor P1 was previously moved via OP_DeferredSeek, complete that
+** seek operation now, without further delay.  If the cursor seek has
+** already occurred, this instruction is a no-op.
+*/
+case OP_FinishSeek: {        /* ncycle */
+  VdbeCursor *pC;            /* The P1 index cursor */
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  if( pC->deferredMoveto ){
+    rc = sqlite3VdbeFinishMoveto(pC);
+    if( rc ) goto abort_due_to_error;
+  }
+  break;
+}
+
+/* Opcode: IdxGE P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** The P4 register values beginning with P3 form an unpacked index
+** key that omits the PRIMARY KEY.  Compare this key value against the index
+** that P1 is currently pointing to, ignoring the PRIMARY KEY or ROWID
+** fields at the end.
+**
+** If the P1 index entry is greater than or equal to the key value
+** then jump to P2.  Otherwise fall through to the next instruction.
+*/
+/* Opcode: IdxGT P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** The P4 register values beginning with P3 form an unpacked index
+** key that omits the PRIMARY KEY.  Compare this key value against the index
+** that P1 is currently pointing to, ignoring the PRIMARY KEY or ROWID
+** fields at the end.
+**
+** If the P1 index entry is greater than the key value
+** then jump to P2.  Otherwise fall through to the next instruction.
+*/
+/* Opcode: IdxLT P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** The P4 register values beginning with P3 form an unpacked index
+** key that omits the PRIMARY KEY or ROWID.  Compare this key value against
+** the index that P1 is currently pointing to, ignoring the PRIMARY KEY or
+** ROWID on the P1 index.
+**
+** If the P1 index entry is less than the key value then jump to P2.
+** Otherwise fall through to the next instruction.
+*/
+/* Opcode: IdxLE P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** The P4 register values beginning with P3 form an unpacked index
+** key that omits the PRIMARY KEY or ROWID.  Compare this key value against
+** the index that P1 is currently pointing to, ignoring the PRIMARY KEY or
+** ROWID on the P1 index.
+**
+** If the P1 index entry is less than or equal to the key value then jump
+** to P2. Otherwise fall through to the next instruction.
+*/
+case OP_IdxLE:          /* jump, ncycle */
+case OP_IdxGT:          /* jump, ncycle */
+case OP_IdxLT:          /* jump, ncycle */
+case OP_IdxGE:  {       /* jump, ncycle */
+  VdbeCursor *pC;
+  int res;
+  UnpackedRecord r;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->isOrdered );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->uc.pCursor!=0);
+  assert( pC->deferredMoveto==0 );
+  assert( pOp->p4type==P4_INT32 );
+  r.pKeyInfo = pC->pKeyInfo;
+  r.nField = (u16)pOp->p4.i;
+  if( pOp->opcode<OP_IdxLT ){
+    assert( pOp->opcode==OP_IdxLE || pOp->opcode==OP_IdxGT );
+    r.default_rc = -1;
+  }else{
+    assert( pOp->opcode==OP_IdxGE || pOp->opcode==OP_IdxLT );
+    r.default_rc = 0;
+  }
+  r.aMem = &aMem[pOp->p3];
+#ifdef SQLITE_DEBUG
+  {
+    int i;
+    for(i=0; i<r.nField; i++){
+      assert( memIsValid(&r.aMem[i]) );
+      REGISTER_TRACE(pOp->p3+i, &aMem[pOp->p3+i]);
+    }
+  }
+#endif
+
+  /* Inlined version of sqlite3VdbeIdxKeyCompare() */
+  {
+    i64 nCellKey = 0;
+    BtCursor *pCur;
+    Mem m;
+
+    assert( pC->eCurType==CURTYPE_BTREE );
+    pCur = pC->uc.pCursor;
+    assert( sqlite3BtreeCursorIsValid(pCur) );
+    nCellKey = sqlite3BtreePayloadSize(pCur);
+    /* nCellKey will always be between 0 and 0xffffffff because of the way
+    ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
+    if( nCellKey<=0 || nCellKey>0x7fffffff ){
+      rc = SQLITE_CORRUPT_BKPT;
+      goto abort_due_to_error;
+    }
+    sqlite3VdbeMemInit(&m, db, 0);
+    rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
+    if( rc ) goto abort_due_to_error;
+    res = sqlite3VdbeRecordCompareWithSkip(m.n, m.z, &r, 0);
+    sqlite3VdbeMemReleaseMalloc(&m);
+  }
+  /* End of inlined sqlite3VdbeIdxKeyCompare() */
+
+  assert( (OP_IdxLE&1)==(OP_IdxLT&1) && (OP_IdxGE&1)==(OP_IdxGT&1) );
+  if( (pOp->opcode&1)==(OP_IdxLT&1) ){
+    assert( pOp->opcode==OP_IdxLE || pOp->opcode==OP_IdxLT );
+    res = -res;
+  }else{
+    assert( pOp->opcode==OP_IdxGE || pOp->opcode==OP_IdxGT );
+    res++;
+  }
+  VdbeBranchTaken(res>0,2);
+  assert( rc==SQLITE_OK );
+  if( res>0 ) goto jump_to_p2;
+  break;
+}
+
+/* Opcode: Destroy P1 P2 P3 * *
+**
+** Delete an entire database table or index whose root page in the database
+** file is given by P1.
+**
+** The table being destroyed is in the main database file if P3==0.  If
+** P3==1 then the table to be destroyed is in the auxiliary database file
+** that is used to store tables create using CREATE TEMPORARY TABLE.
+**
+** If AUTOVACUUM is enabled then it is possible that another root page
+** might be moved into the newly deleted root page in order to keep all
+** root pages contiguous at the beginning of the database.  The former
+** value of the root page that moved - its value before the move occurred -
+** is stored in register P2. If no page movement was required (because the
+** table being dropped was already the last one in the database) then a
+** zero is stored in register P2.  If AUTOVACUUM is disabled then a zero
+** is stored in register P2.
+**
+** This opcode throws an error if there are any active reader VMs when
+** it is invoked. This is done to avoid the difficulty associated with
+** updating existing cursors when a root page is moved in an AUTOVACUUM
+** database. This error is thrown even if the database is not an AUTOVACUUM
+** db in order to avoid introducing an incompatibility between autovacuum
+** and non-autovacuum modes.
+**
+** See also: Clear
+*/
+case OP_Destroy: {     /* out2 */
+  int iMoved;
+  int iDb;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  assert( p->readOnly==0 );
+  assert( pOp->p1>1 );
+  pOut = out2Prerelease(p, pOp);
+  pOut->flags = MEM_Null;
+  if( db->nVdbeRead > db->nVDestroy+1 ){
+    rc = SQLITE_LOCKED;
+    p->errorAction = OE_Abort;
+    goto abort_due_to_error;
+  }else{
+    iDb = pOp->p3;
+    assert( DbMaskTest(p->btreeMask, iDb) );
+    iMoved = 0;  /* Not needed.  Only to silence a warning. */
+    rc = sqlite3BtreeDropTable(db->aDb[iDb].pBt, pOp->p1, &iMoved);
+    pOut->flags = MEM_Int;
+    pOut->u.i = iMoved;
+    if( rc ) goto abort_due_to_error;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( iMoved!=0 ){
+      sqlite3RootPageMoved(db, iDb, iMoved, pOp->p1);
+      /* All OP_Destroy operations occur on the same btree */
+      assert( resetSchemaOnFault==0 || resetSchemaOnFault==iDb+1 );
+      resetSchemaOnFault = iDb+1;
+    }
+#endif
+  }
+  break;
+}
+
+/* Opcode: Clear P1 P2 P3
+**
+** Delete all contents of the database table or index whose root page
+** in the database file is given by P1.  But, unlike Destroy, do not
+** remove the table or index from the database file.
+**
+** The table being cleared is in the main database file if P2==0.  If
+** P2==1 then the table to be cleared is in the auxiliary database file
+** that is used to store tables create using CREATE TEMPORARY TABLE.
+**
+** If the P3 value is non-zero, then the row change count is incremented
+** by the number of rows in the table being cleared. If P3 is greater
+** than zero, then the value stored in register P3 is also incremented
+** by the number of rows in the table being cleared.
+**
+** See also: Destroy
+*/
+case OP_Clear: {
+  i64 nChange;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  nChange = 0;
+  assert( p->readOnly==0 );
+  assert( DbMaskTest(p->btreeMask, pOp->p2) );
+  rc = sqlite3BtreeClearTable(db->aDb[pOp->p2].pBt, (u32)pOp->p1, &nChange);
+  if( pOp->p3 ){
+    p->nChange += nChange;
+    if( pOp->p3>0 ){
+      assert( memIsValid(&aMem[pOp->p3]) );
+      memAboutToChange(p, &aMem[pOp->p3]);
+      aMem[pOp->p3].u.i += nChange;
+    }
+  }
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+
+/* Opcode: ResetSorter P1 * * * *
+**
+** Delete all contents from the ephemeral table or sorter
+** that is open on cursor P1.
+**
+** This opcode only works for cursors used for sorting and
+** opened with OP_OpenEphemeral or OP_SorterOpen.
+*/
+case OP_ResetSorter: {
+  VdbeCursor *pC;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  if( isSorter(pC) ){
+    sqlite3VdbeSorterReset(db, pC->uc.pSorter);
+  }else{
+    assert( pC->eCurType==CURTYPE_BTREE );
+    assert( pC->isEphemeral );
+    rc = sqlite3BtreeClearTableOfCursor(pC->uc.pCursor);
+    if( rc ) goto abort_due_to_error;
+  }
+  break;
+}
+
+/* Opcode: CreateBtree P1 P2 P3 * *
+** Synopsis: r[P2]=root iDb=P1 flags=P3
+**
+** Allocate a new b-tree in the main database file if P1==0 or in the
+** TEMP database file if P1==1 or in an attached database if
+** P1>1.  The P3 argument must be 1 (BTREE_INTKEY) for a rowid table
+** it must be 2 (BTREE_BLOBKEY) for an index or WITHOUT ROWID table.
+** The root page number of the new b-tree is stored in register P2.
+*/
+case OP_CreateBtree: {          /* out2 */
+  Pgno pgno;
+  Db *pDb;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  pOut = out2Prerelease(p, pOp);
+  pgno = 0;
+  assert( pOp->p3==BTREE_INTKEY || pOp->p3==BTREE_BLOBKEY );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p1) );
+  assert( p->readOnly==0 );
+  pDb = &db->aDb[pOp->p1];
+  assert( pDb->pBt!=0 );
+  rc = sqlite3BtreeCreateTable(pDb->pBt, &pgno, pOp->p3);
+  if( rc ) goto abort_due_to_error;
+  pOut->u.i = pgno;
+  break;
+}
+
+/* Opcode: SqlExec P1 P2 * P4 *
+**
+** Run the SQL statement or statements specified in the P4 string.
+**
+** The P1 parameter is a bitmask of options:
+**
+**    0x0001     Disable Auth and Trace callbacks while the statements
+**               in P4 are running.
+**
+**    0x0002     Set db->nAnalysisLimit to P2 while the statements in
+**               P4 are running.
+**
+*/
+case OP_SqlExec: {
+  char *zErr;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth;
+#endif
+  u8 mTrace;
+  int savedAnalysisLimit;
+
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  db->nSqlExec++;
+  zErr = 0;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  xAuth = db->xAuth;
+#endif
+  mTrace = db->mTrace;
+  savedAnalysisLimit = db->nAnalysisLimit;
+  if( pOp->p1 & 0x0001 ){
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    db->xAuth = 0;
+#endif
+    db->mTrace = 0;
+  }
+  if( pOp->p1 & 0x0002 ){
+    db->nAnalysisLimit = pOp->p2;
+  }
+  rc = sqlite3_exec(db, pOp->p4.z, 0, 0, &zErr);
+  db->nSqlExec--;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+  db->mTrace = mTrace;
+  db->nAnalysisLimit = savedAnalysisLimit;
+  if( zErr || rc ){
+    sqlite3VdbeError(p, "%s", zErr);
+    sqlite3_free(zErr);
+    if( rc==SQLITE_NOMEM ) goto no_mem;
+    goto abort_due_to_error;
+  }
+  break;
+}
+
+/* Opcode: ParseSchema P1 * * P4 *
+**
+** Read and parse all entries from the schema table of database P1
+** that match the WHERE clause P4.  If P4 is a NULL pointer, then the
+** entire schema for P1 is reparsed.
+**
+** This opcode invokes the parser to create a new virtual machine,
+** then runs the new virtual machine.  It is thus a re-entrant opcode.
+*/
+case OP_ParseSchema: {
+  int iDb;
+  const char *zSchema;
+  char *zSql;
+  InitData initData;
+
+  /* Any prepared statement that invokes this opcode will hold mutexes
+  ** on every btree.  This is a prerequisite for invoking
+  ** sqlite3InitCallback().
+  */
+#ifdef SQLITE_DEBUG
+  for(iDb=0; iDb<db->nDb; iDb++){
+    assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
+  }
+#endif
+
+  iDb = pOp->p1;
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( DbHasProperty(db, iDb, DB_SchemaLoaded)
+           || db->mallocFailed
+           || (CORRUPT_DB && (db->flags & SQLITE_NoSchemaError)!=0) );
+
+#ifndef SQLITE_OMIT_ALTERTABLE
+  if( pOp->p4.z==0 ){
+    sqlite3SchemaClear(db->aDb[iDb].pSchema);
+    db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
+    rc = sqlite3InitOne(db, iDb, &p->zErrMsg, pOp->p5);
+    db->mDbFlags |= DBFLAG_SchemaChange;
+    p->expired = 0;
+  }else
+#endif
+  {
+    zSchema = LEGACY_SCHEMA_TABLE;
+    initData.db = db;
+    initData.iDb = iDb;
+    initData.pzErrMsg = &p->zErrMsg;
+    initData.mInitFlags = 0;
+    initData.mxPage = sqlite3BtreeLastPage(db->aDb[iDb].pBt);
+    zSql = sqlite3MPrintf(db,
+       "SELECT*FROM\"%w\".%s WHERE %s ORDER BY rowid",
+       db->aDb[iDb].zDbSName, zSchema, pOp->p4.z);
+    if( zSql==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      assert( db->init.busy==0 );
+      db->init.busy = 1;
+      initData.rc = SQLITE_OK;
+      initData.nInitRow = 0;
+      assert( !db->mallocFailed );
+      rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
+      if( rc==SQLITE_OK ) rc = initData.rc;
+      if( rc==SQLITE_OK && initData.nInitRow==0 ){
+        /* The OP_ParseSchema opcode with a non-NULL P4 argument should parse
+        ** at least one SQL statement. Any less than that indicates that
+        ** the sqlite_schema table is corrupt. */
+        rc = SQLITE_CORRUPT_BKPT;
+      }
+      sqlite3DbFreeNN(db, zSql);
+      db->init.busy = 0;
+    }
+  }
+  if( rc ){
+    sqlite3ResetAllSchemasOfConnection(db);
+    if( rc==SQLITE_NOMEM ){
+      goto no_mem;
+    }
+    goto abort_due_to_error;
+  }
+  break;
+}
+
+#if !defined(SQLITE_OMIT_ANALYZE)
+/* Opcode: LoadAnalysis P1 * * * *
+**
+** Read the sqlite_stat1 table for database P1 and load the content
+** of that table into the internal index hash table.  This will cause
+** the analysis to be used when preparing all subsequent queries.
+*/
+case OP_LoadAnalysis: {
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  rc = sqlite3AnalysisLoad(db, pOp->p1);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* !defined(SQLITE_OMIT_ANALYZE) */
+
+/* Opcode: DropTable P1 * * P4 *
+**
+** Remove the internal (in-memory) data structures that describe
+** the table named P4 in database P1.  This is called after a table
+** is dropped from disk (using the Destroy opcode) in order to keep
+** the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropTable: {
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  sqlite3UnlinkAndDeleteTable(db, pOp->p1, pOp->p4.z);
+  break;
+}
+
+/* Opcode: DropIndex P1 * * P4 *
+**
+** Remove the internal (in-memory) data structures that describe
+** the index named P4 in database P1.  This is called after an index
+** is dropped from disk (using the Destroy opcode)
+** in order to keep the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropIndex: {
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  sqlite3UnlinkAndDeleteIndex(db, pOp->p1, pOp->p4.z);
+  break;
+}
+
+/* Opcode: DropTrigger P1 * * P4 *
+**
+** Remove the internal (in-memory) data structures that describe
+** the trigger named P4 in database P1.  This is called after a trigger
+** is dropped from disk (using the Destroy opcode) in order to keep
+** the internal representation of the
+** schema consistent with what is on disk.
+*/
+case OP_DropTrigger: {
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  sqlite3UnlinkAndDeleteTrigger(db, pOp->p1, pOp->p4.z);
+  break;
+}
+
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+/* Opcode: IntegrityCk P1 P2 P3 P4 P5
+**
+** Do an analysis of the currently open database.  Store in
+** register (P1+1) the text of an error message describing any problems.
+** If no problems are found, store a NULL in register (P1+1).
+**
+** The register (P1) contains one less than the maximum number of allowed
+** errors.  At most reg(P1) errors will be reported.
+** In other words, the analysis stops as soon as reg(P1) errors are
+** seen.  Reg(P1) is updated with the number of errors remaining.
+**
+** The root page numbers of all tables in the database are integers
+** stored in P4_INTARRAY argument.
+**
+** If P5 is not zero, the check is done on the auxiliary database
+** file, not the main database file.
+**
+** This opcode is used to implement the integrity_check pragma.
+*/
+case OP_IntegrityCk: {
+  int nRoot;      /* Number of tables to check.  (Number of root pages.) */
+  Pgno *aRoot;    /* Array of rootpage numbers for tables to be checked */
+  int nErr;       /* Number of errors reported */
+  char *z;        /* Text of the error report */
+  Mem *pnErr;     /* Register keeping track of errors remaining */
+
+  assert( p->bIsReader );
+  assert( pOp->p4type==P4_INTARRAY );
+  nRoot = pOp->p2;
+  aRoot = pOp->p4.ai;
+  assert( nRoot>0 );
+  assert( aRoot!=0 );
+  assert( aRoot[0]==(Pgno)nRoot );
+  assert( pOp->p1>0 && (pOp->p1+1)<=(p->nMem+1 - p->nCursor) );
+  pnErr = &aMem[pOp->p1];
+  assert( (pnErr->flags & MEM_Int)!=0 );
+  assert( (pnErr->flags & (MEM_Str|MEM_Blob))==0 );
+  pIn1 = &aMem[pOp->p1+1];
+  assert( pOp->p5<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p5) );
+  rc = sqlite3BtreeIntegrityCheck(db, db->aDb[pOp->p5].pBt, &aRoot[1],
+      &aMem[pOp->p3], nRoot, (int)pnErr->u.i+1, &nErr, &z);
+  sqlite3VdbeMemSetNull(pIn1);
+  if( nErr==0 ){
+    assert( z==0 );
+  }else if( rc ){
+    sqlite3_free(z);
+    goto abort_due_to_error;
+  }else{
+    pnErr->u.i -= nErr-1;
+    sqlite3VdbeMemSetStr(pIn1, z, -1, SQLITE_UTF8, sqlite3_free);
+  }
+  UPDATE_MAX_BLOBSIZE(pIn1);
+  sqlite3VdbeChangeEncoding(pIn1, encoding);
+  goto check_for_interrupt;
+}
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+/* Opcode: RowSetAdd P1 P2 * * *
+** Synopsis: rowset(P1)=r[P2]
+**
+** Insert the integer value held by register P2 into a RowSet object
+** held in register P1.
+**
+** An assertion fails if P2 is not an integer.
+*/
+case OP_RowSetAdd: {       /* in1, in2 */
+  pIn1 = &aMem[pOp->p1];
+  pIn2 = &aMem[pOp->p2];
+  assert( (pIn2->flags & MEM_Int)!=0 );
+  if( (pIn1->flags & MEM_Blob)==0 ){
+    if( sqlite3VdbeMemSetRowSet(pIn1) ) goto no_mem;
+  }
+  assert( sqlite3VdbeMemIsRowSet(pIn1) );
+  sqlite3RowSetInsert((RowSet*)pIn1->z, pIn2->u.i);
+  break;
+}
+
+/* Opcode: RowSetRead P1 P2 P3 * *
+** Synopsis: r[P3]=rowset(P1)
+**
+** Extract the smallest value from the RowSet object in P1
+** and put that value into register P3.
+** Or, if RowSet object P1 is initially empty, leave P3
+** unchanged and jump to instruction P2.
+*/
+case OP_RowSetRead: {       /* jump, in1, out3 */
+  i64 val;
+
+  pIn1 = &aMem[pOp->p1];
+  assert( (pIn1->flags & MEM_Blob)==0 || sqlite3VdbeMemIsRowSet(pIn1) );
+  if( (pIn1->flags & MEM_Blob)==0
+   || sqlite3RowSetNext((RowSet*)pIn1->z, &val)==0
+  ){
+    /* The boolean index is empty */
+    sqlite3VdbeMemSetNull(pIn1);
+    VdbeBranchTaken(1,2);
+    goto jump_to_p2_and_check_for_interrupt;
+  }else{
+    /* A value was pulled from the index */
+    VdbeBranchTaken(0,2);
+    sqlite3VdbeMemSetInt64(&aMem[pOp->p3], val);
+  }
+  goto check_for_interrupt;
+}
+
+/* Opcode: RowSetTest P1 P2 P3 P4
+** Synopsis: if r[P3] in rowset(P1) goto P2
+**
+** Register P3 is assumed to hold a 64-bit integer value. If register P1
+** contains a RowSet object and that RowSet object contains
+** the value held in P3, jump to register P2. Otherwise, insert the
+** integer in P3 into the RowSet and continue on to the
+** next opcode.
+**
+** The RowSet object is optimized for the case where sets of integers
+** are inserted in distinct phases, which each set contains no duplicates.
+** Each set is identified by a unique P4 value. The first set
+** must have P4==0, the final set must have P4==-1, and for all other sets
+** must have P4>0.
+**
+** This allows optimizations: (a) when P4==0 there is no need to test
+** the RowSet object for P3, as it is guaranteed not to contain it,
+** (b) when P4==-1 there is no need to insert the value, as it will
+** never be tested for, and (c) when a value that is part of set X is
+** inserted, there is no need to search to see if the same value was
+** previously inserted as part of set X (only if it was previously
+** inserted as part of some other set).
+*/
+case OP_RowSetTest: {                     /* jump, in1, in3 */
+  int iSet;
+  int exists;
+
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
+  iSet = pOp->p4.i;
+  assert( pIn3->flags&MEM_Int );
+
+  /* If there is anything other than a rowset object in memory cell P1,
+  ** delete it now and initialize P1 with an empty rowset
+  */
+  if( (pIn1->flags & MEM_Blob)==0 ){
+    if( sqlite3VdbeMemSetRowSet(pIn1) ) goto no_mem;
+  }
+  assert( sqlite3VdbeMemIsRowSet(pIn1) );
+  assert( pOp->p4type==P4_INT32 );
+  assert( iSet==-1 || iSet>=0 );
+  if( iSet ){
+    exists = sqlite3RowSetTest((RowSet*)pIn1->z, iSet, pIn3->u.i);
+    VdbeBranchTaken(exists!=0,2);
+    if( exists ) goto jump_to_p2;
+  }
+  if( iSet>=0 ){
+    sqlite3RowSetInsert((RowSet*)pIn1->z, pIn3->u.i);
+  }
+  break;
+}
+
+
+#ifndef SQLITE_OMIT_TRIGGER
+
+/* Opcode: Program P1 P2 P3 P4 P5
+**
+** Execute the trigger program passed as P4 (type P4_SUBPROGRAM).
+**
+** P1 contains the address of the memory cell that contains the first memory
+** cell in an array of values used as arguments to the sub-program. P2
+** contains the address to jump to if the sub-program throws an IGNORE
+** exception using the RAISE() function. P2 might be zero, if there is
+** no possibility that an IGNORE exception will be raised.
+** Register P3 contains the address
+** of a memory cell in this (the parent) VM that is used to allocate the
+** memory required by the sub-vdbe at runtime.
+**
+** P4 is a pointer to the VM containing the trigger program.
+**
+** If P5 is non-zero, then recursive program invocation is enabled.
+*/
+case OP_Program: {        /* jump0 */
+  int nMem;               /* Number of memory registers for sub-program */
+  int nByte;              /* Bytes of runtime space required for sub-program */
+  Mem *pRt;               /* Register to allocate runtime space */
+  Mem *pMem;              /* Used to iterate through memory cells */
+  Mem *pEnd;              /* Last memory cell in new array */
+  VdbeFrame *pFrame;      /* New vdbe frame to execute in */
+  SubProgram *pProgram;   /* Sub-program to execute */
+  void *t;                /* Token identifying trigger */
+
+  pProgram = pOp->p4.pProgram;
+  pRt = &aMem[pOp->p3];
+  assert( pProgram->nOp>0 );
+
+  /* If the p5 flag is clear, then recursive invocation of triggers is
+  ** disabled for backwards compatibility (p5 is set if this sub-program
+  ** is really a trigger, not a foreign key action, and the flag set
+  ** and cleared by the "PRAGMA recursive_triggers" command is clear).
+  **
+  ** It is recursive invocation of triggers, at the SQL level, that is
+  ** disabled. In some cases a single trigger may generate more than one
+  ** SubProgram (if the trigger may be executed with more than one different
+  ** ON CONFLICT algorithm). SubProgram structures associated with a
+  ** single trigger all have the same value for the SubProgram.token
+  ** variable.  */
+  if( pOp->p5 ){
+    t = pProgram->token;
+    for(pFrame=p->pFrame; pFrame && pFrame->token!=t; pFrame=pFrame->pParent);
+    if( pFrame ) break;
+  }
+
+  if( p->nFrame>=db->aLimit[SQLITE_LIMIT_TRIGGER_DEPTH] ){
+    rc = SQLITE_ERROR;
+    sqlite3VdbeError(p, "too many levels of trigger recursion");
+    goto abort_due_to_error;
+  }
+
+  /* Register pRt is used to store the memory required to save the state
+  ** of the current program, and the memory required at runtime to execute
+  ** the trigger program. If this trigger has been fired before, then pRt
+  ** is already allocated. Otherwise, it must be initialized.  */
+  if( (pRt->flags&MEM_Blob)==0 ){
+    /* SubProgram.nMem is set to the number of memory cells used by the
+    ** program stored in SubProgram.aOp. As well as these, one memory
+    ** cell is required for each cursor used by the program. Set local
+    ** variable nMem (and later, VdbeFrame.nChildMem) to this value.
+    */
+    nMem = pProgram->nMem + pProgram->nCsr;
+    assert( nMem>0 );
+    if( pProgram->nCsr==0 ) nMem++;
+    nByte = ROUND8(sizeof(VdbeFrame))
+              + nMem * sizeof(Mem)
+              + pProgram->nCsr * sizeof(VdbeCursor*)
+              + (pProgram->nOp + 7)/8;
+    pFrame = sqlite3DbMallocZero(db, nByte);
+    if( !pFrame ){
+      goto no_mem;
+    }
+    sqlite3VdbeMemRelease(pRt);
+    pRt->flags = MEM_Blob|MEM_Dyn;
+    pRt->z = (char*)pFrame;
+    pRt->n = nByte;
+    pRt->xDel = sqlite3VdbeFrameMemDel;
+
+    pFrame->v = p;
+    pFrame->nChildMem = nMem;
+    pFrame->nChildCsr = pProgram->nCsr;
+    pFrame->pc = (int)(pOp - aOp);
+    pFrame->aMem = p->aMem;
+    pFrame->nMem = p->nMem;
+    pFrame->apCsr = p->apCsr;
+    pFrame->nCursor = p->nCursor;
+    pFrame->aOp = p->aOp;
+    pFrame->nOp = p->nOp;
+    pFrame->token = pProgram->token;
+#ifdef SQLITE_DEBUG
+    pFrame->iFrameMagic = SQLITE_FRAME_MAGIC;
+#endif
+
+    pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
+    for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
+      pMem->flags = MEM_Undefined;
+      pMem->db = db;
+    }
+  }else{
+    pFrame = (VdbeFrame*)pRt->z;
+    assert( pRt->xDel==sqlite3VdbeFrameMemDel );
+    assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem
+        || (pProgram->nCsr==0 && pProgram->nMem+1==pFrame->nChildMem) );
+    assert( pProgram->nCsr==pFrame->nChildCsr );
+    assert( (int)(pOp - aOp)==pFrame->pc );
+  }
+
+  p->nFrame++;
+  pFrame->pParent = p->pFrame;
+  pFrame->lastRowid = db->lastRowid;
+  pFrame->nChange = p->nChange;
+  pFrame->nDbChange = p->db->nChange;
+  assert( pFrame->pAuxData==0 );
+  pFrame->pAuxData = p->pAuxData;
+  p->pAuxData = 0;
+  p->nChange = 0;
+  p->pFrame = pFrame;
+  p->aMem = aMem = VdbeFrameMem(pFrame);
+  p->nMem = pFrame->nChildMem;
+  p->nCursor = (u16)pFrame->nChildCsr;
+  p->apCsr = (VdbeCursor **)&aMem[p->nMem];
+  pFrame->aOnce = (u8*)&p->apCsr[pProgram->nCsr];
+  memset(pFrame->aOnce, 0, (pProgram->nOp + 7)/8);
+  p->aOp = aOp = pProgram->aOp;
+  p->nOp = pProgram->nOp;
+#ifdef SQLITE_DEBUG
+  /* Verify that second and subsequent executions of the same trigger do not
+  ** try to reuse register values from the first use. */
+  {
+    int i;
+    for(i=0; i<p->nMem; i++){
+      aMem[i].pScopyFrom = 0;  /* Prevent false-positive AboutToChange() errs */
+      MemSetTypeFlag(&aMem[i], MEM_Undefined); /* Fault if this reg is reused */
+    }
+  }
+#endif
+  pOp = &aOp[-1];
+  goto check_for_interrupt;
+}
+
+/* Opcode: Param P1 P2 * * *
+**
+** This opcode is only ever present in sub-programs called via the
+** OP_Program instruction. Copy a value currently stored in a memory
+** cell of the calling (parent) frame to cell P2 in the current frames
+** address space. This is used by trigger programs to access the new.*
+** and old.* values.
+**
+** The address of the cell in the parent frame is determined by adding
+** the value of the P1 argument to the value of the P1 argument to the
+** calling OP_Program instruction.
+*/
+case OP_Param: {           /* out2 */
+  VdbeFrame *pFrame;
+  Mem *pIn;
+  pOut = out2Prerelease(p, pOp);
+  pFrame = p->pFrame;
+  pIn = &pFrame->aMem[pOp->p1 + pFrame->aOp[pFrame->pc].p1];
+  sqlite3VdbeMemShallowCopy(pOut, pIn, MEM_Ephem);
+  break;
+}
+
+#endif /* #ifndef SQLITE_OMIT_TRIGGER */
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+/* Opcode: FkCounter P1 P2 * * *
+** Synopsis: fkctr[P1]+=P2
+**
+** Increment a "constraint counter" by P2 (P2 may be negative or positive).
+** If P1 is non-zero, the database constraint counter is incremented
+** (deferred foreign key constraints). Otherwise, if P1 is zero, the
+** statement counter is incremented (immediate foreign key constraints).
+*/
+case OP_FkCounter: {
+  if( db->flags & SQLITE_DeferFKs ){
+    db->nDeferredImmCons += pOp->p2;
+  }else if( pOp->p1 ){
+    db->nDeferredCons += pOp->p2;
+  }else{
+    p->nFkConstraint += pOp->p2;
+  }
+  break;
+}
+
+/* Opcode: FkIfZero P1 P2 * * *
+** Synopsis: if fkctr[P1]==0 goto P2
+**
+** This opcode tests if a foreign key constraint-counter is currently zero.
+** If so, jump to instruction P2. Otherwise, fall through to the next
+** instruction.
+**
+** If P1 is non-zero, then the jump is taken if the database constraint-counter
+** is zero (the one that counts deferred constraint violations). If P1 is
+** zero, the jump is taken if the statement constraint-counter is zero
+** (immediate foreign key constraint violations).
+*/
+case OP_FkIfZero: {         /* jump */
+  if( pOp->p1 ){
+    VdbeBranchTaken(db->nDeferredCons==0 && db->nDeferredImmCons==0, 2);
+    if( db->nDeferredCons==0 && db->nDeferredImmCons==0 ) goto jump_to_p2;
+  }else{
+    VdbeBranchTaken(p->nFkConstraint==0 && db->nDeferredImmCons==0, 2);
+    if( p->nFkConstraint==0 && db->nDeferredImmCons==0 ) goto jump_to_p2;
+  }
+  break;
+}
+#endif /* #ifndef SQLITE_OMIT_FOREIGN_KEY */
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+/* Opcode: MemMax P1 P2 * * *
+** Synopsis: r[P1]=max(r[P1],r[P2])
+**
+** P1 is a register in the root frame of this VM (the root frame is
+** different from the current frame if this instruction is being executed
+** within a sub-program). Set the value of register P1 to the maximum of
+** its current value and the value in register P2.
+**
+** This instruction throws an error if the memory cell is not initially
+** an integer.
+*/
+case OP_MemMax: {        /* in2 */
+  VdbeFrame *pFrame;
+  if( p->pFrame ){
+    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
+    pIn1 = &pFrame->aMem[pOp->p1];
+  }else{
+    pIn1 = &aMem[pOp->p1];
+  }
+  assert( memIsValid(pIn1) );
+  sqlite3VdbeMemIntegerify(pIn1);
+  pIn2 = &aMem[pOp->p2];
+  sqlite3VdbeMemIntegerify(pIn2);
+  if( pIn1->u.i<pIn2->u.i){
+    pIn1->u.i = pIn2->u.i;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_AUTOINCREMENT */
+
+/* Opcode: IfPos P1 P2 P3 * *
+** Synopsis: if r[P1]>0 then r[P1]-=P3, goto P2
+**
+** Register P1 must contain an integer.
+** If the value of register P1 is 1 or greater, subtract P3 from the
+** value in P1 and jump to P2.
+**
+** If the initial value of register P1 is less than 1, then the
+** value is unchanged and control passes through to the next instruction.
+*/
+case OP_IfPos: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags&MEM_Int );
+  VdbeBranchTaken( pIn1->u.i>0, 2);
+  if( pIn1->u.i>0 ){
+    pIn1->u.i -= pOp->p3;
+    goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: OffsetLimit P1 P2 P3 * *
+** Synopsis: if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1)
+**
+** This opcode performs a commonly used computation associated with
+** LIMIT and OFFSET processing.  r[P1] holds the limit counter.  r[P3]
+** holds the offset counter.  The opcode computes the combined value
+** of the LIMIT and OFFSET and stores that value in r[P2].  The r[P2]
+** value computed is the total number of rows that will need to be
+** visited in order to complete the query.
+**
+** If r[P3] is zero or negative, that means there is no OFFSET
+** and r[P2] is set to be the value of the LIMIT, r[P1].
+**
+** if r[P1] is zero or negative, that means there is no LIMIT
+** and r[P2] is set to -1.
+**
+** Otherwise, r[P2] is set to the sum of r[P1] and r[P3].
+*/
+case OP_OffsetLimit: {    /* in1, out2, in3 */
+  i64 x;
+  pIn1 = &aMem[pOp->p1];
+  pIn3 = &aMem[pOp->p3];
+  pOut = out2Prerelease(p, pOp);
+  assert( pIn1->flags & MEM_Int );
+  assert( pIn3->flags & MEM_Int );
+  x = pIn1->u.i;
+  if( x<=0 || sqlite3AddInt64(&x, pIn3->u.i>0?pIn3->u.i:0) ){
+    /* If the LIMIT is less than or equal to zero, loop forever.  This
+    ** is documented.  But also, if the LIMIT+OFFSET exceeds 2^63 then
+    ** also loop forever.  This is undocumented.  In fact, one could argue
+    ** that the loop should terminate.  But assuming 1 billion iterations
+    ** per second (far exceeding the capabilities of any current hardware)
+    ** it would take nearly 300 years to actually reach the limit.  So
+    ** looping forever is a reasonable approximation. */
+    pOut->u.i = -1;
+  }else{
+    pOut->u.i = x;
+  }
+  break;
+}
+
+/* Opcode: IfNotZero P1 P2 * * *
+** Synopsis: if r[P1]!=0 then r[P1]--, goto P2
+**
+** Register P1 must contain an integer.  If the content of register P1 is
+** initially greater than zero, then decrement the value in register P1.
+** If it is non-zero (negative or positive) and then also jump to P2.
+** If register P1 is initially zero, leave it unchanged and fall through.
+*/
+case OP_IfNotZero: {        /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags&MEM_Int );
+  VdbeBranchTaken(pIn1->u.i<0, 2);
+  if( pIn1->u.i ){
+     if( pIn1->u.i>0 ) pIn1->u.i--;
+     goto jump_to_p2;
+  }
+  break;
+}
+
+/* Opcode: DecrJumpZero P1 P2 * * *
+** Synopsis: if (--r[P1])==0 goto P2
+**
+** Register P1 must hold an integer.  Decrement the value in P1
+** and jump to P2 if the new value is exactly zero.
+*/
+case OP_DecrJumpZero: {      /* jump, in1 */
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags&MEM_Int );
+  if( pIn1->u.i>SMALLEST_INT64 ) pIn1->u.i--;
+  VdbeBranchTaken(pIn1->u.i==0, 2);
+  if( pIn1->u.i==0 ) goto jump_to_p2;
+  break;
+}
+
+
+/* Opcode: AggStep * P2 P3 P4 P5
+** Synopsis: accum=r[P3] step(r[P2@P5])
+**
+** Execute the xStep function for an aggregate.
+** The function has P5 arguments.  P4 is a pointer to the
+** FuncDef structure that specifies the function.  Register P3 is the
+** accumulator.
+**
+** The P5 arguments are taken from register P2 and its
+** successors.
+*/
+/* Opcode: AggInverse * P2 P3 P4 P5
+** Synopsis: accum=r[P3] inverse(r[P2@P5])
+**
+** Execute the xInverse function for an aggregate.
+** The function has P5 arguments.  P4 is a pointer to the
+** FuncDef structure that specifies the function.  Register P3 is the
+** accumulator.
+**
+** The P5 arguments are taken from register P2 and its
+** successors.
+*/
+/* Opcode: AggStep1 P1 P2 P3 P4 P5
+** Synopsis: accum=r[P3] step(r[P2@P5])
+**
+** Execute the xStep (if P1==0) or xInverse (if P1!=0) function for an
+** aggregate.  The function has P5 arguments.  P4 is a pointer to the
+** FuncDef structure that specifies the function.  Register P3 is the
+** accumulator.
+**
+** The P5 arguments are taken from register P2 and its
+** successors.
+**
+** This opcode is initially coded as OP_AggStep0.  On first evaluation,
+** the FuncDef stored in P4 is converted into an sqlite3_context and
+** the opcode is changed.  In this way, the initialization of the
+** sqlite3_context only happens once, instead of on each call to the
+** step function.
+*/
+case OP_AggInverse:
+case OP_AggStep: {
+  int n;
+  sqlite3_context *pCtx;
+  u64 nAlloc;
+
+  assert( pOp->p4type==P4_FUNCDEF );
+  n = pOp->p5;
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem+1 - p->nCursor)+1) );
+  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
+
+  /* Allocate space for (a) the context object and (n-1) extra pointers
+  ** to append to the sqlite3_context.argv[1] array, and (b) a memory
+  ** cell in which to store the accumulation. Be careful that the memory
+  ** cell is 8-byte aligned, even on platforms where a pointer is 32-bits.
+  **
+  ** Note: We could avoid this by using a regular memory cell from aMem[] for
+  ** the accumulator, instead of allocating one here. */
+  nAlloc = ROUND8P( sizeof(pCtx[0]) + (n-1)*sizeof(sqlite3_value*) );
+  pCtx = sqlite3DbMallocRawNN(db, nAlloc + sizeof(Mem));
+  if( pCtx==0 ) goto no_mem;
+  pCtx->pOut = (Mem*)((u8*)pCtx + nAlloc);
+  assert( EIGHT_BYTE_ALIGNMENT(pCtx->pOut) );
+
+  sqlite3VdbeMemInit(pCtx->pOut, db, MEM_Null);
+  pCtx->pMem = 0;
+  pCtx->pFunc = pOp->p4.pFunc;
+  pCtx->iOp = (int)(pOp - aOp);
+  pCtx->pVdbe = p;
+  pCtx->skipFlag = 0;
+  pCtx->isError = 0;
+  pCtx->enc = encoding;
+  pCtx->argc = n;
+  pOp->p4type = P4_FUNCCTX;
+  pOp->p4.pCtx = pCtx;
+
+  /* OP_AggInverse must have P1==1 and OP_AggStep must have P1==0 */
+  assert( pOp->p1==(pOp->opcode==OP_AggInverse) );
+
+  pOp->opcode = OP_AggStep1;
+  /* Fall through into OP_AggStep */
+  /* no break */ deliberate_fall_through
+}
+case OP_AggStep1: {
+  int i;
+  sqlite3_context *pCtx;
+  Mem *pMem;
+
+  assert( pOp->p4type==P4_FUNCCTX );
+  pCtx = pOp->p4.pCtx;
+  pMem = &aMem[pOp->p3];
+
+#ifdef SQLITE_DEBUG
+  if( pOp->p1 ){
+    /* This is an OP_AggInverse call.  Verify that xStep has always
+    ** been called at least once prior to any xInverse call. */
+    assert( pMem->uTemp==0x1122e0e3 );
+  }else{
+    /* This is an OP_AggStep call.  Mark it as such. */
+    pMem->uTemp = 0x1122e0e3;
+  }
+#endif
+
+  /* If this function is inside of a trigger, the register array in aMem[]
+  ** might change from one evaluation to the next.  The next block of code
+  ** checks to see if the register array has changed, and if so it
+  ** reinitializes the relevant parts of the sqlite3_context object */
+  if( pCtx->pMem != pMem ){
+    pCtx->pMem = pMem;
+    for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
+  }
+
+#ifdef SQLITE_DEBUG
+  for(i=0; i<pCtx->argc; i++){
+    assert( memIsValid(pCtx->argv[i]) );
+    REGISTER_TRACE(pOp->p2+i, pCtx->argv[i]);
+  }
+#endif
+
+  pMem->n++;
+  assert( pCtx->pOut->flags==MEM_Null );
+  assert( pCtx->isError==0 );
+  assert( pCtx->skipFlag==0 );
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( pOp->p1 ){
+    (pCtx->pFunc->xInverse)(pCtx,pCtx->argc,pCtx->argv);
+  }else
+#endif
+  (pCtx->pFunc->xSFunc)(pCtx,pCtx->argc,pCtx->argv); /* IMP: R-24505-23230 */
+
+  if( pCtx->isError ){
+    if( pCtx->isError>0 ){
+      sqlite3VdbeError(p, "%s", sqlite3_value_text(pCtx->pOut));
+      rc = pCtx->isError;
+    }
+    if( pCtx->skipFlag ){
+      assert( pOp[-1].opcode==OP_CollSeq );
+      i = pOp[-1].p1;
+      if( i ) sqlite3VdbeMemSetInt64(&aMem[i], 1);
+      pCtx->skipFlag = 0;
+    }
+    sqlite3VdbeMemRelease(pCtx->pOut);
+    pCtx->pOut->flags = MEM_Null;
+    pCtx->isError = 0;
+    if( rc ) goto abort_due_to_error;
+  }
+  assert( pCtx->pOut->flags==MEM_Null );
+  assert( pCtx->skipFlag==0 );
+  break;
+}
+
+/* Opcode: AggFinal P1 P2 * P4 *
+** Synopsis: accum=r[P1] N=P2
+**
+** P1 is the memory location that is the accumulator for an aggregate
+** or window function.  Execute the finalizer function
+** for an aggregate and store the result in P1.
+**
+** P2 is the number of arguments that the step function takes and
+** P4 is a pointer to the FuncDef for this function.  The P2
+** argument is not used by this opcode.  It is only there to disambiguate
+** functions that can take varying numbers of arguments.  The
+** P4 argument is only needed for the case where
+** the step function was not previously called.
+*/
+/* Opcode: AggValue * P2 P3 P4 *
+** Synopsis: r[P3]=value N=P2
+**
+** Invoke the xValue() function and store the result in register P3.
+**
+** P2 is the number of arguments that the step function takes and
+** P4 is a pointer to the FuncDef for this function.  The P2
+** argument is not used by this opcode.  It is only there to disambiguate
+** functions that can take varying numbers of arguments.  The
+** P4 argument is only needed for the case where
+** the step function was not previously called.
+*/
+case OP_AggValue:
+case OP_AggFinal: {
+  Mem *pMem;
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  assert( pOp->p3==0 || pOp->opcode==OP_AggValue );
+  pMem = &aMem[pOp->p1];
+  assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( pOp->p3 ){
+    memAboutToChange(p, &aMem[pOp->p3]);
+    rc = sqlite3VdbeMemAggValue(pMem, &aMem[pOp->p3], pOp->p4.pFunc);
+    pMem = &aMem[pOp->p3];
+  }else
+#endif
+  {
+    rc = sqlite3VdbeMemFinalize(pMem, pOp->p4.pFunc);
+  }
+
+  if( rc ){
+    sqlite3VdbeError(p, "%s", sqlite3_value_text(pMem));
+    goto abort_due_to_error;
+  }
+  sqlite3VdbeChangeEncoding(pMem, encoding);
+  UPDATE_MAX_BLOBSIZE(pMem);
+  REGISTER_TRACE((int)(pMem-aMem), pMem);
+  break;
+}
+
+#ifndef SQLITE_OMIT_WAL
+/* Opcode: Checkpoint P1 P2 P3 * *
+**
+** Checkpoint database P1. This is a no-op if P1 is not currently in
+** WAL mode. Parameter P2 is one of SQLITE_CHECKPOINT_PASSIVE, FULL,
+** RESTART, or TRUNCATE.  Write 1 or 0 into mem[P3] if the checkpoint returns
+** SQLITE_BUSY or not, respectively.  Write the number of pages in the
+** WAL after the checkpoint into mem[P3+1] and the number of pages
+** in the WAL that have been checkpointed after the checkpoint
+** completes into mem[P3+2].  However on an error, mem[P3+1] and
+** mem[P3+2] are initialized to -1.
+*/
+case OP_Checkpoint: {
+  int i;                          /* Loop counter */
+  int aRes[3];                    /* Results */
+  Mem *pMem;                      /* Write results here */
+
+  assert( p->readOnly==0 );
+  aRes[0] = 0;
+  aRes[1] = aRes[2] = -1;
+  assert( pOp->p2==SQLITE_CHECKPOINT_PASSIVE
+       || pOp->p2==SQLITE_CHECKPOINT_FULL
+       || pOp->p2==SQLITE_CHECKPOINT_RESTART
+       || pOp->p2==SQLITE_CHECKPOINT_TRUNCATE
+  );
+  rc = sqlite3Checkpoint(db, pOp->p1, pOp->p2, &aRes[1], &aRes[2]);
+  if( rc ){
+    if( rc!=SQLITE_BUSY ) goto abort_due_to_error;
+    rc = SQLITE_OK;
+    aRes[0] = 1;
+  }
+  for(i=0, pMem = &aMem[pOp->p3]; i<3; i++, pMem++){
+    sqlite3VdbeMemSetInt64(pMem, (i64)aRes[i]);
+  }
+  break;
+};
+#endif
+
+#ifndef SQLITE_OMIT_PRAGMA
+/* Opcode: JournalMode P1 P2 P3 * *
+**
+** Change the journal mode of database P1 to P3. P3 must be one of the
+** PAGER_JOURNALMODE_XXX values. If changing between the various rollback
+** modes (delete, truncate, persist, off and memory), this is a simple
+** operation. No IO is required.
+**
+** If changing into or out of WAL mode the procedure is more complicated.
+**
+** Write a string containing the final journal-mode to register P2.
+*/
+case OP_JournalMode: {    /* out2 */
+  Btree *pBt;                     /* Btree to change journal mode of */
+  Pager *pPager;                  /* Pager associated with pBt */
+  int eNew;                       /* New journal mode */
+  int eOld;                       /* The old journal mode */
+#ifndef SQLITE_OMIT_WAL
+  const char *zFilename;          /* Name of database file for pPager */
+#endif
+
+  pOut = out2Prerelease(p, pOp);
+  eNew = pOp->p3;
+  assert( eNew==PAGER_JOURNALMODE_DELETE
+       || eNew==PAGER_JOURNALMODE_TRUNCATE
+       || eNew==PAGER_JOURNALMODE_PERSIST
+       || eNew==PAGER_JOURNALMODE_OFF
+       || eNew==PAGER_JOURNALMODE_MEMORY
+       || eNew==PAGER_JOURNALMODE_WAL
+       || eNew==PAGER_JOURNALMODE_QUERY
+  );
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( p->readOnly==0 );
+
+  pBt = db->aDb[pOp->p1].pBt;
+  pPager = sqlite3BtreePager(pBt);
+  eOld = sqlite3PagerGetJournalMode(pPager);
+  if( eNew==PAGER_JOURNALMODE_QUERY ) eNew = eOld;
+  assert( sqlite3BtreeHoldsMutex(pBt) );
+  if( !sqlite3PagerOkToChangeJournalMode(pPager) ) eNew = eOld;
+
+#ifndef SQLITE_OMIT_WAL
+  zFilename = sqlite3PagerFilename(pPager, 1);
+
+  /* Do not allow a transition to journal_mode=WAL for a database
+  ** in temporary storage or if the VFS does not support shared memory
+  */
+  if( eNew==PAGER_JOURNALMODE_WAL
+   && (sqlite3Strlen30(zFilename)==0           /* Temp file */
+       || !sqlite3PagerWalSupported(pPager))   /* No shared-memory support */
+  ){
+    eNew = eOld;
+  }
+
+  if( (eNew!=eOld)
+   && (eOld==PAGER_JOURNALMODE_WAL || eNew==PAGER_JOURNALMODE_WAL)
+  ){
+    if( !db->autoCommit || db->nVdbeRead>1 ){
+      rc = SQLITE_ERROR;
+      sqlite3VdbeError(p,
+          "cannot change %s wal mode from within a transaction",
+          (eNew==PAGER_JOURNALMODE_WAL ? "into" : "out of")
+      );
+      goto abort_due_to_error;
+    }else{
+
+      if( eOld==PAGER_JOURNALMODE_WAL ){
+        /* If leaving WAL mode, close the log file. If successful, the call
+        ** to PagerCloseWal() checkpoints and deletes the write-ahead-log
+        ** file. An EXCLUSIVE lock may still be held on the database file
+        ** after a successful return.
+        */
+        rc = sqlite3PagerCloseWal(pPager, db);
+        if( rc==SQLITE_OK ){
+          sqlite3PagerSetJournalMode(pPager, eNew);
+        }
+      }else if( eOld==PAGER_JOURNALMODE_MEMORY ){
+        /* Cannot transition directly from MEMORY to WAL.  Use mode OFF
+        ** as an intermediate */
+        sqlite3PagerSetJournalMode(pPager, PAGER_JOURNALMODE_OFF);
+      }
+
+      /* Open a transaction on the database file. Regardless of the journal
+      ** mode, this transaction always uses a rollback journal.
+      */
+      assert( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_WRITE );
+      if( rc==SQLITE_OK ){
+        rc = sqlite3BtreeSetVersion(pBt, (eNew==PAGER_JOURNALMODE_WAL ? 2 : 1));
+      }
+    }
+  }
+#endif /* ifndef SQLITE_OMIT_WAL */
+
+  if( rc ) eNew = eOld;
+  eNew = sqlite3PagerSetJournalMode(pPager, eNew);
+
+  pOut->flags = MEM_Str|MEM_Static|MEM_Term;
+  pOut->z = (char *)sqlite3JournalModename(eNew);
+  pOut->n = sqlite3Strlen30(pOut->z);
+  pOut->enc = SQLITE_UTF8;
+  sqlite3VdbeChangeEncoding(pOut, encoding);
+  if( rc ) goto abort_due_to_error;
+  break;
+};
+#endif /* SQLITE_OMIT_PRAGMA */
+
+#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
+/* Opcode: Vacuum P1 P2 * * *
+**
+** Vacuum the entire database P1.  P1 is 0 for "main", and 2 or more
+** for an attached database.  The "temp" database may not be vacuumed.
+**
+** If P2 is not zero, then it is a register holding a string which is
+** the file into which the result of vacuum should be written.  When
+** P2 is zero, the vacuum overwrites the original database.
+*/
+case OP_Vacuum: {
+  assert( p->readOnly==0 );
+  rc = sqlite3RunVacuum(&p->zErrMsg, db, pOp->p1,
+                        pOp->p2 ? &aMem[pOp->p2] : 0);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif
+
+#if !defined(SQLITE_OMIT_AUTOVACUUM)
+/* Opcode: IncrVacuum P1 P2 * * *
+**
+** Perform a single step of the incremental vacuum procedure on
+** the P1 database. If the vacuum has finished, jump to instruction
+** P2. Otherwise, fall through to the next instruction.
+*/
+case OP_IncrVacuum: {        /* jump */
+  Btree *pBt;
+
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  assert( DbMaskTest(p->btreeMask, pOp->p1) );
+  assert( p->readOnly==0 );
+  pBt = db->aDb[pOp->p1].pBt;
+  rc = sqlite3BtreeIncrVacuum(pBt);
+  VdbeBranchTaken(rc==SQLITE_DONE,2);
+  if( rc ){
+    if( rc!=SQLITE_DONE ) goto abort_due_to_error;
+    rc = SQLITE_OK;
+    goto jump_to_p2;
+  }
+  break;
+}
+#endif
+
+/* Opcode: Expire P1 P2 * * *
+**
+** Cause precompiled statements to expire.  When an expired statement
+** is executed using sqlite3_step() it will either automatically
+** reprepare itself (if it was originally created using sqlite3_prepare_v2())
+** or it will fail with SQLITE_SCHEMA.
+**
+** If P1 is 0, then all SQL statements become expired. If P1 is non-zero,
+** then only the currently executing statement is expired.
+**
+** If P2 is 0, then SQL statements are expired immediately.  If P2 is 1,
+** then running SQL statements are allowed to continue to run to completion.
+** The P2==1 case occurs when a CREATE INDEX or similar schema change happens
+** that might help the statement run faster but which does not affect the
+** correctness of operation.
+*/
+case OP_Expire: {
+  assert( pOp->p2==0 || pOp->p2==1 );
+  if( !pOp->p1 ){
+    sqlite3ExpirePreparedStatements(db, pOp->p2);
+  }else{
+    p->expired = pOp->p2+1;
+  }
+  break;
+}
+
+/* Opcode: CursorLock P1 * * * *
+**
+** Lock the btree to which cursor P1 is pointing so that the btree cannot be
+** written by an other cursor.
+*/
+case OP_CursorLock: {
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  sqlite3BtreeCursorPin(pC->uc.pCursor);
+  break;
+}
+
+/* Opcode: CursorUnlock P1 * * * *
+**
+** Unlock the btree to which cursor P1 is pointing so that it can be
+** written by other cursors.
+*/
+case OP_CursorUnlock: {
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  sqlite3BtreeCursorUnpin(pC->uc.pCursor);
+  break;
+}
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/* Opcode: TableLock P1 P2 P3 P4 *
+** Synopsis: iDb=P1 root=P2 write=P3
+**
+** Obtain a lock on a particular table. This instruction is only used when
+** the shared-cache feature is enabled.
+**
+** P1 is the index of the database in sqlite3.aDb[] of the database
+** on which the lock is acquired.  A readlock is obtained if P3==0 or
+** a write lock if P3==1.
+**
+** P2 contains the root-page of the table to lock.
+**
+** P4 contains a pointer to the name of the table being locked. This is only
+** used to generate an error message if the lock cannot be obtained.
+*/
+case OP_TableLock: {
+  u8 isWriteLock = (u8)pOp->p3;
+  if( isWriteLock || 0==(db->flags&SQLITE_ReadUncommit) ){
+    int p1 = pOp->p1;
+    assert( p1>=0 && p1<db->nDb );
+    assert( DbMaskTest(p->btreeMask, p1) );
+    assert( isWriteLock==0 || isWriteLock==1 );
+    rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
+    if( rc ){
+      if( (rc&0xFF)==SQLITE_LOCKED ){
+        const char *z = pOp->p4.z;
+        sqlite3VdbeError(p, "database table is locked: %s", z);
+      }
+      goto abort_due_to_error;
+    }
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_SHARED_CACHE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VBegin * * * P4 *
+**
+** P4 may be a pointer to an sqlite3_vtab structure. If so, call the
+** xBegin method for that table.
+**
+** Also, whether or not P4 is set, check that this is not being called from
+** within a callback to a virtual table xSync() method. If it is, the error
+** code will be set to SQLITE_LOCKED.
+*/
+case OP_VBegin: {
+  VTable *pVTab;
+  pVTab = pOp->p4.pVtab;
+  rc = sqlite3VtabBegin(db, pVTab);
+  if( pVTab ) sqlite3VtabImportErrmsg(p, pVTab->pVtab);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VCreate P1 P2 * * *
+**
+** P2 is a register that holds the name of a virtual table in database
+** P1. Call the xCreate method for that table.
+*/
+case OP_VCreate: {
+  Mem sMem;          /* For storing the record being decoded */
+  const char *zTab;  /* Name of the virtual table */
+
+  memset(&sMem, 0, sizeof(sMem));
+  sMem.db = db;
+  /* Because P2 is always a static string, it is impossible for the
+  ** sqlite3VdbeMemCopy() to fail */
+  assert( (aMem[pOp->p2].flags & MEM_Str)!=0 );
+  assert( (aMem[pOp->p2].flags & MEM_Static)!=0 );
+  rc = sqlite3VdbeMemCopy(&sMem, &aMem[pOp->p2]);
+  assert( rc==SQLITE_OK );
+  zTab = (const char*)sqlite3_value_text(&sMem);
+  assert( zTab || db->mallocFailed );
+  if( zTab ){
+    rc = sqlite3VtabCallCreate(db, pOp->p1, zTab, &p->zErrMsg);
+  }
+  sqlite3VdbeMemRelease(&sMem);
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VDestroy P1 * * P4 *
+**
+** P4 is the name of a virtual table in database P1.  Call the xDestroy method
+** of that table.
+*/
+case OP_VDestroy: {
+  db->nVDestroy++;
+  rc = sqlite3VtabCallDestroy(db, pOp->p1, pOp->p4.z);
+  db->nVDestroy--;
+  assert( p->errorAction==OE_Abort && p->usesStmtJournal );
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VOpen P1 * * P4 *
+**
+** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** P1 is a cursor number.  This opcode opens a cursor to the virtual
+** table and stores that cursor in P1.
+*/
+case OP_VOpen: {             /* ncycle */
+  VdbeCursor *pCur;
+  sqlite3_vtab_cursor *pVCur;
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+
+  assert( p->bIsReader );
+  pCur = 0;
+  pVCur = 0;
+  pVtab = pOp->p4.pVtab->pVtab;
+  if( pVtab==0 || NEVER(pVtab->pModule==0) ){
+    rc = SQLITE_LOCKED;
+    goto abort_due_to_error;
+  }
+  pModule = pVtab->pModule;
+  rc = pModule->xOpen(pVtab, &pVCur);
+  sqlite3VtabImportErrmsg(p, pVtab);
+  if( rc ) goto abort_due_to_error;
+
+  /* Initialize sqlite3_vtab_cursor base class */
+  pVCur->pVtab = pVtab;
+
+  /* Initialize vdbe cursor object */
+  pCur = allocateCursor(p, pOp->p1, 0, CURTYPE_VTAB);
+  if( pCur ){
+    pCur->uc.pVCur = pVCur;
+    pVtab->nRef++;
+  }else{
+    assert( db->mallocFailed );
+    pModule->xClose(pVCur);
+    goto no_mem;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VCheck P1 P2 P3 P4 *
+**
+** P4 is a pointer to a Table object that is a virtual table in schema P1
+** that supports the xIntegrity() method.  This opcode runs the xIntegrity()
+** method for that virtual table, using P3 as the integer argument.  If
+** an error is reported back, the table name is prepended to the error
+** message and that message is stored in P2.  If no errors are seen,
+** register P2 is set to NULL.
+*/
+case OP_VCheck: {             /* out2 */
+  Table *pTab;
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+  char *zErr = 0;
+
+  pOut = &aMem[pOp->p2];
+  sqlite3VdbeMemSetNull(pOut);  /* Innocent until proven guilty */
+  assert( pOp->p4type==P4_TABLEREF );
+  pTab = pOp->p4.pTab;
+  assert( pTab!=0 );
+  assert( pTab->nTabRef>0 );
+  assert( IsVirtual(pTab) );
+  if( pTab->u.vtab.p==0 ) break;
+  pVtab = pTab->u.vtab.p->pVtab;
+  assert( pVtab!=0 );
+  pModule = pVtab->pModule;
+  assert( pModule!=0 );
+  assert( pModule->iVersion>=4 );
+  assert( pModule->xIntegrity!=0 );
+  sqlite3VtabLock(pTab->u.vtab.p);
+  assert( pOp->p1>=0 && pOp->p1<db->nDb );
+  rc = pModule->xIntegrity(pVtab, db->aDb[pOp->p1].zDbSName, pTab->zName,
+                           pOp->p3, &zErr);
+  sqlite3VtabUnlock(pTab->u.vtab.p);
+  if( rc ){
+    sqlite3_free(zErr);
+    goto abort_due_to_error;
+  }
+  if( zErr ){
+    sqlite3VdbeMemSetStr(pOut, zErr, -1, SQLITE_UTF8, sqlite3_free);
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VInitIn P1 P2 P3 * *
+** Synopsis: r[P2]=ValueList(P1,P3)
+**
+** Set register P2 to be a pointer to a ValueList object for cursor P1
+** with cache register P3 and output register P3+1.  This ValueList object
+** can be used as the first argument to sqlite3_vtab_in_first() and
+** sqlite3_vtab_in_next() to extract all of the values stored in the P1
+** cursor.  Register P3 is used to hold the values returned by
+** sqlite3_vtab_in_first() and sqlite3_vtab_in_next().
+*/
+case OP_VInitIn: {        /* out2, ncycle */
+  VdbeCursor *pC;         /* The cursor containing the RHS values */
+  ValueList *pRhs;        /* New ValueList object to put in reg[P2] */
+
+  pC = p->apCsr[pOp->p1];
+  pRhs = sqlite3_malloc64( sizeof(*pRhs) );
+  if( pRhs==0 ) goto no_mem;
+  pRhs->pCsr = pC->uc.pCursor;
+  pRhs->pOut = &aMem[pOp->p3];
+  pOut = out2Prerelease(p, pOp);
+  pOut->flags = MEM_Null;
+  sqlite3VdbeMemSetPointer(pOut, pRhs, "ValueList", sqlite3VdbeValueListFree);
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VFilter P1 P2 P3 P4 *
+** Synopsis: iplan=r[P3] zplan='P4'
+**
+** P1 is a cursor opened using VOpen.  P2 is an address to jump to if
+** the filtered result set is empty.
+**
+** P4 is either NULL or a string that was generated by the xBestIndex
+** method of the module.  The interpretation of the P4 string is left
+** to the module implementation.
+**
+** This opcode invokes the xFilter method on the virtual table specified
+** by P1.  The integer query plan parameter to xFilter is stored in register
+** P3. Register P3+1 stores the argc parameter to be passed to the
+** xFilter method. Registers P3+2..P3+1+argc are the argc
+** additional parameters which are passed to
+** xFilter as argv. Register P3+2 becomes argv[0] when passed to xFilter.
+**
+** A jump is made to P2 if the result set after filtering would be empty.
+*/
+case OP_VFilter: {   /* jump, ncycle */
+  int nArg;
+  int iQuery;
+  const sqlite3_module *pModule;
+  Mem *pQuery;
+  Mem *pArgc;
+  sqlite3_vtab_cursor *pVCur;
+  sqlite3_vtab *pVtab;
+  VdbeCursor *pCur;
+  int res;
+  int i;
+  Mem **apArg;
+
+  pQuery = &aMem[pOp->p3];
+  pArgc = &pQuery[1];
+  pCur = p->apCsr[pOp->p1];
+  assert( memIsValid(pQuery) );
+  REGISTER_TRACE(pOp->p3, pQuery);
+  assert( pCur!=0 );
+  assert( pCur->eCurType==CURTYPE_VTAB );
+  pVCur = pCur->uc.pVCur;
+  pVtab = pVCur->pVtab;
+  pModule = pVtab->pModule;
+
+  /* Grab the index number and argc parameters */
+  assert( (pQuery->flags&MEM_Int)!=0 && pArgc->flags==MEM_Int );
+  nArg = (int)pArgc->u.i;
+  iQuery = (int)pQuery->u.i;
+
+  /* Invoke the xFilter method */
+  apArg = p->apArg;
+  for(i = 0; i<nArg; i++){
+    apArg[i] = &pArgc[i+1];
+  }
+  rc = pModule->xFilter(pVCur, iQuery, pOp->p4.z, nArg, apArg);
+  sqlite3VtabImportErrmsg(p, pVtab);
+  if( rc ) goto abort_due_to_error;
+  res = pModule->xEof(pVCur);
+  pCur->nullRow = 0;
+  VdbeBranchTaken(res!=0,2);
+  if( res ) goto jump_to_p2;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VColumn P1 P2 P3 * P5
+** Synopsis: r[P3]=vcolumn(P2)
+**
+** Store in register P3 the value of the P2-th column of
+** the current row of the virtual-table of cursor P1.
+**
+** If the VColumn opcode is being used to fetch the value of
+** an unchanging column during an UPDATE operation, then the P5
+** value is OPFLAG_NOCHNG.  This will cause the sqlite3_vtab_nochange()
+** function to return true inside the xColumn method of the virtual
+** table implementation.  The P5 column might also contain other
+** bits (OPFLAG_LENGTHARG or OPFLAG_TYPEOFARG) but those bits are
+** unused by OP_VColumn.
+*/
+case OP_VColumn: {           /* ncycle */
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+  Mem *pDest;
+  sqlite3_context sContext;
+  FuncDef nullFunc;
+
+  VdbeCursor *pCur = p->apCsr[pOp->p1];
+  assert( pCur!=0 );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  pDest = &aMem[pOp->p3];
+  memAboutToChange(p, pDest);
+  if( pCur->nullRow ){
+    sqlite3VdbeMemSetNull(pDest);
+    break;
+  }
+  assert( pCur->eCurType==CURTYPE_VTAB );
+  pVtab = pCur->uc.pVCur->pVtab;
+  pModule = pVtab->pModule;
+  assert( pModule->xColumn );
+  memset(&sContext, 0, sizeof(sContext));
+  sContext.pOut = pDest;
+  sContext.enc = encoding;
+  nullFunc.pUserData = 0;
+  nullFunc.funcFlags = SQLITE_RESULT_SUBTYPE;
+  sContext.pFunc = &nullFunc;
+  assert( pOp->p5==OPFLAG_NOCHNG || pOp->p5==0 );
+  if( pOp->p5 & OPFLAG_NOCHNG ){
+    sqlite3VdbeMemSetNull(pDest);
+    pDest->flags = MEM_Null|MEM_Zero;
+    pDest->u.nZero = 0;
+  }else{
+    MemSetTypeFlag(pDest, MEM_Null);
+  }
+  rc = pModule->xColumn(pCur->uc.pVCur, &sContext, pOp->p2);
+  sqlite3VtabImportErrmsg(p, pVtab);
+  if( sContext.isError>0 ){
+    sqlite3VdbeError(p, "%s", sqlite3_value_text(pDest));
+    rc = sContext.isError;
+  }
+  sqlite3VdbeChangeEncoding(pDest, encoding);
+  REGISTER_TRACE(pOp->p3, pDest);
+  UPDATE_MAX_BLOBSIZE(pDest);
+
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VNext P1 P2 * * *
+**
+** Advance virtual table P1 to the next row in its result set and
+** jump to instruction P2.  Or, if the virtual table has reached
+** the end of its result set, then fall through to the next instruction.
+*/
+case OP_VNext: {   /* jump, ncycle */
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+  int res;
+  VdbeCursor *pCur;
+
+  pCur = p->apCsr[pOp->p1];
+  assert( pCur!=0 );
+  assert( pCur->eCurType==CURTYPE_VTAB );
+  if( pCur->nullRow ){
+    break;
+  }
+  pVtab = pCur->uc.pVCur->pVtab;
+  pModule = pVtab->pModule;
+  assert( pModule->xNext );
+
+  /* Invoke the xNext() method of the module. There is no way for the
+  ** underlying implementation to return an error if one occurs during
+  ** xNext(). Instead, if an error occurs, true is returned (indicating that
+  ** data is available) and the error code returned when xColumn or
+  ** some other method is next invoked on the save virtual table cursor.
+  */
+  rc = pModule->xNext(pCur->uc.pVCur);
+  sqlite3VtabImportErrmsg(p, pVtab);
+  if( rc ) goto abort_due_to_error;
+  res = pModule->xEof(pCur->uc.pVCur);
+  VdbeBranchTaken(!res,2);
+  if( !res ){
+    /* If there is data, jump to P2 */
+    goto jump_to_p2_and_check_for_interrupt;
+  }
+  goto check_for_interrupt;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VRename P1 * * P4 *
+**
+** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** This opcode invokes the corresponding xRename method. The value
+** in register P1 is passed as the zName argument to the xRename method.
+*/
+case OP_VRename: {
+  sqlite3_vtab *pVtab;
+  Mem *pName;
+  int isLegacy;
+
+  isLegacy = (db->flags & SQLITE_LegacyAlter);
+  db->flags |= SQLITE_LegacyAlter;
+  pVtab = pOp->p4.pVtab->pVtab;
+  pName = &aMem[pOp->p1];
+  assert( pVtab->pModule->xRename );
+  assert( memIsValid(pName) );
+  assert( p->readOnly==0 );
+  REGISTER_TRACE(pOp->p1, pName);
+  assert( pName->flags & MEM_Str );
+  testcase( pName->enc==SQLITE_UTF8 );
+  testcase( pName->enc==SQLITE_UTF16BE );
+  testcase( pName->enc==SQLITE_UTF16LE );
+  rc = sqlite3VdbeChangeEncoding(pName, SQLITE_UTF8);
+  if( rc ) goto abort_due_to_error;
+  rc = pVtab->pModule->xRename(pVtab, pName->z);
+  if( isLegacy==0 ) db->flags &= ~(u64)SQLITE_LegacyAlter;
+  sqlite3VtabImportErrmsg(p, pVtab);
+  p->expired = 0;
+  if( rc ) goto abort_due_to_error;
+  break;
+}
+#endif
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Opcode: VUpdate P1 P2 P3 P4 P5
+** Synopsis: data=r[P3@P2]
+**
+** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
+** This opcode invokes the corresponding xUpdate method. P2 values
+** are contiguous memory cells starting at P3 to pass to the xUpdate
+** invocation. The value in register (P3+P2-1) corresponds to the
+** p2th element of the argv array passed to xUpdate.
+**
+** The xUpdate method will do a DELETE or an INSERT or both.
+** The argv[0] element (which corresponds to memory cell P3)
+** is the rowid of a row to delete.  If argv[0] is NULL then no
+** deletion occurs.  The argv[1] element is the rowid of the new
+** row.  This can be NULL to have the virtual table select the new
+** rowid for itself.  The subsequent elements in the array are
+** the values of columns in the new row.
+**
+** If P2==1 then no insert is performed.  argv[0] is the rowid of
+** a row to delete.
+**
+** P1 is a boolean flag. If it is set to true and the xUpdate call
+** is successful, then the value returned by sqlite3_last_insert_rowid()
+** is set to the value of the rowid for the row just inserted.
+**
+** P5 is the error actions (OE_Replace, OE_Fail, OE_Ignore, etc) to
+** apply in the case of a constraint failure on an insert or update.
+*/
+case OP_VUpdate: {
+  sqlite3_vtab *pVtab;
+  const sqlite3_module *pModule;
+  int nArg;
+  int i;
+  sqlite_int64 rowid = 0;
+  Mem **apArg;
+  Mem *pX;
+
+  assert( pOp->p2==1        || pOp->p5==OE_Fail   || pOp->p5==OE_Rollback
+       || pOp->p5==OE_Abort || pOp->p5==OE_Ignore || pOp->p5==OE_Replace
+  );
+  assert( p->readOnly==0 );
+  if( db->mallocFailed ) goto no_mem;
+  sqlite3VdbeIncrWriteCounter(p, 0);
+  pVtab = pOp->p4.pVtab->pVtab;
+  if( pVtab==0 || NEVER(pVtab->pModule==0) ){
+    rc = SQLITE_LOCKED;
+    goto abort_due_to_error;
+  }
+  pModule = pVtab->pModule;
+  nArg = pOp->p2;
+  assert( pOp->p4type==P4_VTAB );
+  if( ALWAYS(pModule->xUpdate) ){
+    u8 vtabOnConflict = db->vtabOnConflict;
+    apArg = p->apArg;
+    pX = &aMem[pOp->p3];
+    for(i=0; i<nArg; i++){
+      assert( memIsValid(pX) );
+      memAboutToChange(p, pX);
+      apArg[i] = pX;
+      pX++;
+    }
+    db->vtabOnConflict = pOp->p5;
+    rc = pModule->xUpdate(pVtab, nArg, apArg, &rowid);
+    db->vtabOnConflict = vtabOnConflict;
+    sqlite3VtabImportErrmsg(p, pVtab);
+    if( rc==SQLITE_OK && pOp->p1 ){
+      assert( nArg>1 && apArg[0] && (apArg[0]->flags&MEM_Null) );
+      db->lastRowid = rowid;
+    }
+    if( (rc&0xff)==SQLITE_CONSTRAINT && pOp->p4.pVtab->bConstraint ){
+      if( pOp->p5==OE_Ignore ){
+        rc = SQLITE_OK;
+      }else{
+        p->errorAction = ((pOp->p5==OE_Replace) ? OE_Abort : pOp->p5);
+      }
+    }else{
+      p->nChange++;
+    }
+    if( rc ) goto abort_due_to_error;
+  }
+  break;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef  SQLITE_OMIT_PAGER_PRAGMAS
+/* Opcode: Pagecount P1 P2 * * *
+**
+** Write the current number of pages in database P1 to memory cell P2.
+*/
+case OP_Pagecount: {            /* out2 */
+  pOut = out2Prerelease(p, pOp);
+  pOut->u.i = sqlite3BtreeLastPage(db->aDb[pOp->p1].pBt);
+  break;
+}
+#endif
+
+
+#ifndef  SQLITE_OMIT_PAGER_PRAGMAS
+/* Opcode: MaxPgcnt P1 P2 P3 * *
+**
+** Try to set the maximum page count for database P1 to the value in P3.
+** Do not let the maximum page count fall below the current page count and
+** do not change the maximum page count value if P3==0.
+**
+** Store the maximum page count after the change in register P2.
+*/
+case OP_MaxPgcnt: {            /* out2 */
+  unsigned int newMax;
+  Btree *pBt;
+
+  pOut = out2Prerelease(p, pOp);
+  pBt = db->aDb[pOp->p1].pBt;
+  newMax = 0;
+  if( pOp->p3 ){
+    newMax = sqlite3BtreeLastPage(pBt);
+    if( newMax < (unsigned)pOp->p3 ) newMax = (unsigned)pOp->p3;
+  }
+  pOut->u.i = sqlite3BtreeMaxPageCount(pBt, newMax);
+  break;
+}
+#endif
+
+/* Opcode: Function P1 P2 P3 P4 *
+** Synopsis: r[P3]=func(r[P2@NP])
+**
+** Invoke a user function (P4 is a pointer to an sqlite3_context object that
+** contains a pointer to the function to be run) with arguments taken
+** from register P2 and successors.  The number of arguments is in
+** the sqlite3_context object that P4 points to.
+** The result of the function is stored
+** in register P3.  Register P3 must not be one of the function inputs.
+**
+** P1 is a 32-bit bitmask indicating whether or not each argument to the
+** function was determined to be constant at compile time. If the first
+** argument was constant then bit 0 of P1 is set. This is used to determine
+** whether meta data associated with a user function argument using the
+** sqlite3_set_auxdata() API may be safely retained until the next
+** invocation of this opcode.
+**
+** See also: AggStep, AggFinal, PureFunc
+*/
+/* Opcode: PureFunc P1 P2 P3 P4 *
+** Synopsis: r[P3]=func(r[P2@NP])
+**
+** Invoke a user function (P4 is a pointer to an sqlite3_context object that
+** contains a pointer to the function to be run) with arguments taken
+** from register P2 and successors.  The number of arguments is in
+** the sqlite3_context object that P4 points to.
+** The result of the function is stored
+** in register P3.  Register P3 must not be one of the function inputs.
+**
+** P1 is a 32-bit bitmask indicating whether or not each argument to the
+** function was determined to be constant at compile time. If the first
+** argument was constant then bit 0 of P1 is set. This is used to determine
+** whether meta data associated with a user function argument using the
+** sqlite3_set_auxdata() API may be safely retained until the next
+** invocation of this opcode.
+**
+** This opcode works exactly like OP_Function.  The only difference is in
+** its name.  This opcode is used in places where the function must be
+** purely non-deterministic.  Some built-in date/time functions can be
+** either deterministic of non-deterministic, depending on their arguments.
+** When those function are used in a non-deterministic way, they will check
+** to see if they were called using OP_PureFunc instead of OP_Function, and
+** if they were, they throw an error.
+**
+** See also: AggStep, AggFinal, Function
+*/
+case OP_PureFunc:              /* group */
+case OP_Function: {            /* group */
+  int i;
+  sqlite3_context *pCtx;
+
+  assert( pOp->p4type==P4_FUNCCTX );
+  pCtx = pOp->p4.pCtx;
+
+  /* If this function is inside of a trigger, the register array in aMem[]
+  ** might change from one evaluation to the next.  The next block of code
+  ** checks to see if the register array has changed, and if so it
+  ** reinitializes the relevant parts of the sqlite3_context object */
+  pOut = &aMem[pOp->p3];
+  if( pCtx->pOut != pOut ){
+    pCtx->pVdbe = p;
+    pCtx->pOut = pOut;
+    pCtx->enc = encoding;
+    for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
+  }
+  assert( pCtx->pVdbe==p );
+
+  memAboutToChange(p, pOut);
+#ifdef SQLITE_DEBUG
+  for(i=0; i<pCtx->argc; i++){
+    assert( memIsValid(pCtx->argv[i]) );
+    REGISTER_TRACE(pOp->p2+i, pCtx->argv[i]);
+  }
+#endif
+  MemSetTypeFlag(pOut, MEM_Null);
+  assert( pCtx->isError==0 );
+  (*pCtx->pFunc->xSFunc)(pCtx, pCtx->argc, pCtx->argv);/* IMP: R-24505-23230 */
+
+  /* If the function returned an error, throw an exception */
+  if( pCtx->isError ){
+    if( pCtx->isError>0 ){
+      sqlite3VdbeError(p, "%s", sqlite3_value_text(pOut));
+      rc = pCtx->isError;
+    }
+    sqlite3VdbeDeleteAuxData(db, &p->pAuxData, pCtx->iOp, pOp->p1);
+    pCtx->isError = 0;
+    if( rc ) goto abort_due_to_error;
+  }
+
+  assert( (pOut->flags&MEM_Str)==0
+       || pOut->enc==encoding
+       || db->mallocFailed );
+  assert( !sqlite3VdbeMemTooBig(pOut) );
+
+  REGISTER_TRACE(pOp->p3, pOut);
+  UPDATE_MAX_BLOBSIZE(pOut);
+  break;
+}
+
+/* Opcode: ClrSubtype P1 * * * *
+** Synopsis:  r[P1].subtype = 0
+**
+** Clear the subtype from register P1.
+*/
+case OP_ClrSubtype: {   /* in1 */
+  pIn1 = &aMem[pOp->p1];
+  pIn1->flags &= ~MEM_Subtype;
+  break;
+}
+
+/* Opcode: GetSubtype P1 P2 * * *
+** Synopsis:  r[P2] = r[P1].subtype
+**
+** Extract the subtype value from register P1 and write that subtype
+** into register P2.  If P1 has no subtype, then P1 gets a NULL.
+*/
+case OP_GetSubtype: {   /* in1 out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  if( pIn1->flags & MEM_Subtype ){
+    sqlite3VdbeMemSetInt64(pOut, pIn1->eSubtype);
+  }else{
+    sqlite3VdbeMemSetNull(pOut);
+  }
+  break;
+}
+
+/* Opcode: SetSubtype P1 P2 * * *
+** Synopsis:  r[P2].subtype = r[P1]
+**
+** Set the subtype value of register P2 to the integer from register P1.
+** If P1 is NULL, clear the subtype from p2.
+*/
+case OP_SetSubtype: {   /* in1 out2 */
+  pIn1 = &aMem[pOp->p1];
+  pOut = &aMem[pOp->p2];
+  if( pIn1->flags & MEM_Null ){
+    pOut->flags &= ~MEM_Subtype;
+  }else{
+    assert( pIn1->flags & MEM_Int );
+    pOut->flags |= MEM_Subtype;
+    pOut->eSubtype = (u8)(pIn1->u.i & 0xff);
+  }
+  break;
+}
+
+/* Opcode: FilterAdd P1 * P3 P4 *
+** Synopsis: filter(P1) += key(P3@P4)
+**
+** Compute a hash on the P4 registers starting with r[P3] and
+** add that hash to the bloom filter contained in r[P1].
+*/
+case OP_FilterAdd: {
+  u64 h;
+
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  pIn1 = &aMem[pOp->p1];
+  assert( pIn1->flags & MEM_Blob );
+  assert( pIn1->n>0 );
+  h = filterHash(aMem, pOp);
+#ifdef SQLITE_DEBUG
+  if( db->flags&SQLITE_VdbeTrace ){
+    int ii;
+    for(ii=pOp->p3; ii<pOp->p3+pOp->p4.i; ii++){
+      registerTrace(ii, &aMem[ii]);
+    }
+    printf("hash: %llu modulo %d -> %u\n", h, pIn1->n, (int)(h%pIn1->n));
+  }
+#endif
+  h %= (pIn1->n*8);
+  pIn1->z[h/8] |= 1<<(h&7);
+  break;
+}
+
+/* Opcode: Filter P1 P2 P3 P4 *
+** Synopsis: if key(P3@P4) not in filter(P1) goto P2
+**
+** Compute a hash on the key contained in the P4 registers starting
+** with r[P3].  Check to see if that hash is found in the
+** bloom filter hosted by register P1.  If it is not present then
+** maybe jump to P2.  Otherwise fall through.
+**
+** False negatives are harmless.  It is always safe to fall through,
+** even if the value is in the bloom filter.  A false negative causes
+** more CPU cycles to be used, but it should still yield the correct
+** answer.  However, an incorrect answer may well arise from a
+** false positive - if the jump is taken when it should fall through.
+*/
+case OP_Filter: {          /* jump */
+  u64 h;
+
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
+  pIn1 = &aMem[pOp->p1];
+  assert( (pIn1->flags & MEM_Blob)!=0 );
+  assert( pIn1->n >= 1 );
+  h = filterHash(aMem, pOp);
+#ifdef SQLITE_DEBUG
+  if( db->flags&SQLITE_VdbeTrace ){
+    int ii;
+    for(ii=pOp->p3; ii<pOp->p3+pOp->p4.i; ii++){
+      registerTrace(ii, &aMem[ii]);
+    }
+    printf("hash: %llu modulo %d -> %u\n", h, pIn1->n, (int)(h%pIn1->n));
+  }
+#endif
+  h %= (pIn1->n*8);
+  if( (pIn1->z[h/8] & (1<<(h&7)))==0 ){
+    VdbeBranchTaken(1, 2);
+    p->aCounter[SQLITE_STMTSTATUS_FILTER_HIT]++;
+    goto jump_to_p2;
+  }else{
+    p->aCounter[SQLITE_STMTSTATUS_FILTER_MISS]++;
+    VdbeBranchTaken(0, 2);
+  }
+  break;
+}
+
+/* Opcode: Trace P1 P2 * P4 *
+**
+** Write P4 on the statement trace output if statement tracing is
+** enabled.
+**
+** Operand P1 must be 0x7fffffff and P2 must positive.
+*/
+/* Opcode: Init P1 P2 P3 P4 *
+** Synopsis: Start at P2
+**
+** Programs contain a single instance of this opcode as the very first
+** opcode.
+**
+** If tracing is enabled (by the sqlite3_trace()) interface, then
+** the UTF-8 string contained in P4 is emitted on the trace callback.
+** Or if P4 is blank, use the string returned by sqlite3_sql().
+**
+** If P2 is not zero, jump to instruction P2.
+**
+** Increment the value of P1 so that OP_Once opcodes will jump the
+** first time they are evaluated for this run.
+**
+** If P3 is not zero, then it is an address to jump to if an SQLITE_CORRUPT
+** error is encountered.
+*/
+case OP_Trace:
+case OP_Init: {          /* jump0 */
+  int i;
+#ifndef SQLITE_OMIT_TRACE
+  char *zTrace;
+#endif
+
+  /* If the P4 argument is not NULL, then it must be an SQL comment string.
+  ** The "--" string is broken up to prevent false-positives with srcck1.c.
+  **
+  ** This assert() provides evidence for:
+  ** EVIDENCE-OF: R-50676-09860 The callback can compute the same text that
+  ** would have been returned by the legacy sqlite3_trace() interface by
+  ** using the X argument when X begins with "--" and invoking
+  ** sqlite3_expanded_sql(P) otherwise.
+  */
+  assert( pOp->p4.z==0 || strncmp(pOp->p4.z, "-" "- ", 3)==0 );
+
+  /* OP_Init is always instruction 0 */
+  assert( pOp==p->aOp || pOp->opcode==OP_Trace );
+
+#ifndef SQLITE_OMIT_TRACE
+  if( (db->mTrace & (SQLITE_TRACE_STMT|SQLITE_TRACE_LEGACY))!=0
+   && p->minWriteFileFormat!=254  /* tag-20220401a */
+   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
+  ){
+#ifndef SQLITE_OMIT_DEPRECATED
+    if( db->mTrace & SQLITE_TRACE_LEGACY ){
+      char *z = sqlite3VdbeExpandSql(p, zTrace);
+      db->trace.xLegacy(db->pTraceArg, z);
+      sqlite3_free(z);
+    }else
+#endif
+    if( db->nVdbeExec>1 ){
+      char *z = sqlite3MPrintf(db, "-- %s", zTrace);
+      (void)db->trace.xV2(SQLITE_TRACE_STMT, db->pTraceArg, p, z);
+      sqlite3DbFree(db, z);
+    }else{
+      (void)db->trace.xV2(SQLITE_TRACE_STMT, db->pTraceArg, p, zTrace);
+    }
+  }
+#ifdef SQLITE_USE_FCNTL_TRACE
+  zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql);
+  if( zTrace ){
+    int j;
+    for(j=0; j<db->nDb; j++){
+      if( DbMaskTest(p->btreeMask, j)==0 ) continue;
+      sqlite3_file_control(db, db->aDb[j].zDbSName, SQLITE_FCNTL_TRACE, zTrace);
+    }
+  }
+#endif /* SQLITE_USE_FCNTL_TRACE */
+#ifdef SQLITE_DEBUG
+  if( (db->flags & SQLITE_SqlTrace)!=0
+   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
+  ){
+    sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
+  }
+#endif /* SQLITE_DEBUG */
+#endif /* SQLITE_OMIT_TRACE */
+  assert( pOp->p2>0 );
+  if( pOp->p1>=sqlite3GlobalConfig.iOnceResetThreshold ){
+    if( pOp->opcode==OP_Trace ) break;
+    for(i=1; i<p->nOp; i++){
+      if( p->aOp[i].opcode==OP_Once ) p->aOp[i].p1 = 0;
+    }
+    pOp->p1 = 0;
+  }
+  pOp->p1++;
+  p->aCounter[SQLITE_STMTSTATUS_RUN]++;
+  goto jump_to_p2;
+}
+
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/* Opcode: CursorHint P1 * * P4 *
+**
+** Provide a hint to cursor P1 that it only needs to return rows that
+** satisfy the Expr in P4.  TK_REGISTER terms in the P4 expression refer
+** to values currently held in registers.  TK_COLUMN terms in the P4
+** expression refer to columns in the b-tree to which cursor P1 is pointing.
+*/
+case OP_CursorHint: {
+  VdbeCursor *pC;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p4type==P4_EXPR );
+  pC = p->apCsr[pOp->p1];
+  if( pC ){
+    assert( pC->eCurType==CURTYPE_BTREE );
+    sqlite3BtreeCursorHint(pC->uc.pCursor, BTREE_HINT_RANGE,
+                           pOp->p4.pExpr, aMem);
+  }
+  break;
+}
+#endif /* SQLITE_ENABLE_CURSOR_HINTS */
+
+#ifdef SQLITE_DEBUG
+/* Opcode:  Abortable   * * * * *
+**
+** Verify that an Abort can happen.  Assert if an Abort at this point
+** might cause database corruption.  This opcode only appears in debugging
+** builds.
+**
+** An Abort is safe if either there have been no writes, or if there is
+** an active statement journal.
+*/
+case OP_Abortable: {
+  sqlite3VdbeAssertAbortable(p);
+  break;
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/* Opcode:  ReleaseReg   P1 P2 P3 * P5
+** Synopsis: release r[P1@P2] mask P3
+**
+** Release registers from service.  Any content that was in the
+** the registers is unreliable after this opcode completes.
+**
+** The registers released will be the P2 registers starting at P1,
+** except if bit ii of P3 set, then do not release register P1+ii.
+** In other words, P3 is a mask of registers to preserve.
+**
+** Releasing a register clears the Mem.pScopyFrom pointer.  That means
+** that if the content of the released register was set using OP_SCopy,
+** a change to the value of the source register for the OP_SCopy will no longer
+** generate an assertion fault in sqlite3VdbeMemAboutToChange().
+**
+** If P5 is set, then all released registers have their type set
+** to MEM_Undefined so that any subsequent attempt to read the released
+** register (before it is reinitialized) will generate an assertion fault.
+**
+** P5 ought to be set on every call to this opcode.
+** However, there are places in the code generator will release registers
+** before their are used, under the (valid) assumption that the registers
+** will not be reallocated for some other purpose before they are used and
+** hence are safe to release.
+**
+** This opcode is only available in testing and debugging builds.  It is
+** not generated for release builds.  The purpose of this opcode is to help
+** validate the generated bytecode.  This opcode does not actually contribute
+** to computing an answer.
+*/
+case OP_ReleaseReg: {
+  Mem *pMem;
+  int i;
+  u32 constMask;
+  assert( pOp->p1>0 );
+  assert( pOp->p1+pOp->p2<=(p->nMem+1 - p->nCursor)+1 );
+  pMem = &aMem[pOp->p1];
+  constMask = pOp->p3;
+  for(i=0; i<pOp->p2; i++, pMem++){
+    if( i>=32 || (constMask & MASKBIT32(i))==0 ){
+      pMem->pScopyFrom = 0;
+      if( i<32 && pOp->p5 ) MemSetTypeFlag(pMem, MEM_Undefined);
+    }
+  }
+  break;
+}
+#endif
+
+/* Opcode: Noop * * * * *
+**
+** Do nothing.  Continue downward to the next opcode.
+*/
+/* Opcode: Explain P1 P2 P3 P4 *
+**
+** This is the same as OP_Noop during normal query execution.  The
+** purpose of this opcode is to hold information about the query
+** plan for the purpose of EXPLAIN QUERY PLAN output.
+**
+** The P4 value is human-readable text that describes the query plan
+** element.  Something like "SCAN t1" or "SEARCH t2 USING INDEX t2x1".
+**
+** The P1 value is the ID of the current element and P2 is the parent
+** element for the case of nested query plan elements.  If P2 is zero
+** then this element is a top-level element.
+**
+** For loop elements, P3 is the estimated code of each invocation of this
+** element.
+**
+** As with all opcodes, the meanings of the parameters for OP_Explain
+** are subject to change from one release to the next.  Applications
+** should not attempt to interpret or use any of the information
+** contained in the OP_Explain opcode.  The information provided by this
+** opcode is intended for testing and debugging use only.
+*/
+default: {          /* This is really OP_Noop, OP_Explain */
+  assert( pOp->opcode==OP_Noop || pOp->opcode==OP_Explain );
+
+  break;
+}
+
+/*****************************************************************************
+** The cases of the switch statement above this line should all be indented
+** by 6 spaces.  But the left-most 6 spaces have been removed to improve the
+** readability.  From this point on down, the normal indentation rules are
+** restored.
+*****************************************************************************/
+    }
+
+#if defined(VDBE_PROFILE)
+    *pnCycle += sqlite3NProfileCnt ? sqlite3NProfileCnt : sqlite3Hwtime();
+    pnCycle = 0;
+#elif defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+    if( pnCycle ){
+      *pnCycle += sqlite3Hwtime();
+      pnCycle = 0;
+    }
+#endif
+
+    /* The following code adds nothing to the actual functionality
+    ** of the program.  It is only here for testing and debugging.
+    ** On the other hand, it does burn CPU cycles every time through
+    ** the evaluator loop.  So we can leave it out when NDEBUG is defined.
+    */
+#ifndef NDEBUG
+    assert( pOp>=&aOp[-1] && pOp<&aOp[p->nOp-1] );
+
+#ifdef SQLITE_DEBUG
+    if( db->flags & SQLITE_VdbeTrace ){
+      u8 opProperty = sqlite3OpcodeProperty[pOrigOp->opcode];
+      if( rc!=0 ) printf("rc=%d\n",rc);
+      if( opProperty & (OPFLG_OUT2) ){
+        registerTrace(pOrigOp->p2, &aMem[pOrigOp->p2]);
+      }
+      if( opProperty & OPFLG_OUT3 ){
+        registerTrace(pOrigOp->p3, &aMem[pOrigOp->p3]);
+      }
+      if( opProperty==0xff ){
+        /* Never happens.  This code exists to avoid a harmless linkage
+        ** warning about sqlite3VdbeRegisterDump() being defined but not
+        ** used. */
+        sqlite3VdbeRegisterDump(p);
+      }
+    }
+#endif  /* SQLITE_DEBUG */
+#endif  /* NDEBUG */
+  }  /* The end of the for(;;) loop the loops through opcodes */
+
+  /* If we reach this point, it means that execution is finished with
+  ** an error of some kind.
+  */
+abort_due_to_error:
+  if( db->mallocFailed ){
+    rc = SQLITE_NOMEM_BKPT;
+  }else if( rc==SQLITE_IOERR_CORRUPTFS ){
+    rc = SQLITE_CORRUPT_BKPT;
+  }
+  assert( rc );
+#ifdef SQLITE_DEBUG
+  if( db->flags & SQLITE_VdbeTrace ){
+    const char *zTrace = p->zSql;
+    if( zTrace==0 ){
+      if( aOp[0].opcode==OP_Trace ){
+        zTrace = aOp[0].p4.z;
+      }
+      if( zTrace==0 ) zTrace = "???";
+    }
+    printf("ABORT-due-to-error (rc=%d): %s\n", rc, zTrace);
+  }
+#endif
+  if( p->zErrMsg==0 && rc!=SQLITE_IOERR_NOMEM ){
+    sqlite3VdbeError(p, "%s", sqlite3ErrStr(rc));
+  }
+  p->rc = rc;
+  sqlite3SystemError(db, rc);
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  sqlite3_log(rc, "statement aborts at %d: [%s] %s",
+                   (int)(pOp - aOp), p->zSql, p->zErrMsg);
+  if( p->eVdbeState==VDBE_RUN_STATE ) sqlite3VdbeHalt(p);
+  if( rc==SQLITE_IOERR_NOMEM ) sqlite3OomFault(db);
+  if( rc==SQLITE_CORRUPT && db->autoCommit==0 ){
+    db->flags |= SQLITE_CorruptRdOnly;
+  }
+  rc = SQLITE_ERROR;
+  if( resetSchemaOnFault>0 ){
+    sqlite3ResetOneSchema(db, resetSchemaOnFault-1);
+  }
+
+  /* This is the only way out of this procedure.  We have to
+  ** release the mutexes on btrees that were acquired at the
+  ** top. */
+vdbe_return:
+#if defined(VDBE_PROFILE)
+  if( pnCycle ){
+    *pnCycle += sqlite3NProfileCnt ? sqlite3NProfileCnt : sqlite3Hwtime();
+    pnCycle = 0;
+  }
+#elif defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+  if( pnCycle ){
+    *pnCycle += sqlite3Hwtime();
+    pnCycle = 0;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+  while( nVmStep>=nProgressLimit && db->xProgress!=0 ){
+    nProgressLimit += db->nProgressOps;
+    if( db->xProgress(db->pProgressArg) ){
+      nProgressLimit = LARGEST_UINT64;
+      rc = SQLITE_INTERRUPT;
+      goto abort_due_to_error;
+    }
+  }
+#endif
+  p->aCounter[SQLITE_STMTSTATUS_VM_STEP] += (int)nVmStep;
+  if( DbMaskNonZero(p->lockMask) ){
+    sqlite3VdbeLeave(p);
+  }
+  assert( rc!=SQLITE_OK || nExtraDelete==0
+       || sqlite3_strlike("DELETE%",p->zSql,0)!=0
+  );
+  return rc;
+
+  /* Jump to here if a string or blob larger than SQLITE_MAX_LENGTH
+  ** is encountered.
+  */
+too_big:
+  sqlite3VdbeError(p, "string or blob too big");
+  rc = SQLITE_TOOBIG;
+  goto abort_due_to_error;
+
+  /* Jump to here if a malloc() fails.
+  */
+no_mem:
+  sqlite3OomFault(db);
+  sqlite3VdbeError(p, "out of memory");
+  rc = SQLITE_NOMEM_BKPT;
+  goto abort_due_to_error;
+
+  /* Jump to here if the sqlite3_interrupt() API sets the interrupt
+  ** flag.
+  */
+abort_due_to_interrupt:
+  assert( AtomicLoad(&db->u1.isInterrupted) );
+  rc = SQLITE_INTERRUPT;
+  goto abort_due_to_error;
+}
+
+
+/************** End of vdbe.c ************************************************/
+/************** Begin file vdbeblob.c ****************************************/
+/*
+** 2007 May 1
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code used to implement incremental BLOB I/O.
+*/
+
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+#ifndef SQLITE_OMIT_INCRBLOB
+
+/*
+** Valid sqlite3_blob* handles point to Incrblob structures.
+*/
+typedef struct Incrblob Incrblob;
+struct Incrblob {
+  int nByte;              /* Size of open blob, in bytes */
+  int iOffset;            /* Byte offset of blob in cursor data */
+  u16 iCol;               /* Table column this handle is open on */
+  BtCursor *pCsr;         /* Cursor pointing at blob row */
+  sqlite3_stmt *pStmt;    /* Statement holding cursor open */
+  sqlite3 *db;            /* The associated database */
+  char *zDb;              /* Database name */
+  Table *pTab;            /* Table object */
+};
+
+
+/*
+** This function is used by both blob_open() and blob_reopen(). It seeks
+** the b-tree cursor associated with blob handle p to point to row iRow.
+** If successful, SQLITE_OK is returned and subsequent calls to
+** sqlite3_blob_read() or sqlite3_blob_write() access the specified row.
+**
+** If an error occurs, or if the specified row does not exist or does not
+** contain a value of type TEXT or BLOB in the column nominated when the
+** blob handle was opened, then an error code is returned and *pzErr may
+** be set to point to a buffer containing an error message. It is the
+** responsibility of the caller to free the error message buffer using
+** sqlite3DbFree().
+**
+** If an error does occur, then the b-tree cursor is closed. All subsequent
+** calls to sqlite3_blob_read(), blob_write() or blob_reopen() will
+** immediately return SQLITE_ABORT.
+*/
+static int blobSeekToRow(Incrblob *p, sqlite3_int64 iRow, char **pzErr){
+  int rc;                         /* Error code */
+  char *zErr = 0;                 /* Error message */
+  Vdbe *v = (Vdbe *)p->pStmt;
+
+  /* Set the value of register r[1] in the SQL statement to integer iRow.
+  ** This is done directly as a performance optimization
+  */
+  sqlite3VdbeMemSetInt64(&v->aMem[1], iRow);
+
+  /* If the statement has been run before (and is paused at the OP_ResultRow)
+  ** then back it up to the point where it does the OP_NotExists.  This could
+  ** have been down with an extra OP_Goto, but simply setting the program
+  ** counter is faster. */
+  if( v->pc>4 ){
+    v->pc = 4;
+    assert( v->aOp[v->pc].opcode==OP_NotExists );
+    rc = sqlite3VdbeExec(v);
+  }else{
+    rc = sqlite3_step(p->pStmt);
+  }
+  if( rc==SQLITE_ROW ){
+    VdbeCursor *pC = v->apCsr[0];
+    u32 type;
+    assert( pC!=0 );
+    assert( pC->eCurType==CURTYPE_BTREE );
+    type = pC->nHdrParsed>p->iCol ? pC->aType[p->iCol] : 0;
+    testcase( pC->nHdrParsed==p->iCol );
+    testcase( pC->nHdrParsed==p->iCol+1 );
+    if( type<12 ){
+      zErr = sqlite3MPrintf(p->db, "cannot open value of type %s",
+          type==0?"null": type==7?"real": "integer"
+      );
+      rc = SQLITE_ERROR;
+      sqlite3_finalize(p->pStmt);
+      p->pStmt = 0;
+    }else{
+      p->iOffset = pC->aType[p->iCol + pC->nField];
+      p->nByte = sqlite3VdbeSerialTypeLen(type);
+      p->pCsr =  pC->uc.pCursor;
+      sqlite3BtreeIncrblobCursor(p->pCsr);
+    }
+  }
+
+  if( rc==SQLITE_ROW ){
+    rc = SQLITE_OK;
+  }else if( p->pStmt ){
+    rc = sqlite3_finalize(p->pStmt);
+    p->pStmt = 0;
+    if( rc==SQLITE_OK ){
+      zErr = sqlite3MPrintf(p->db, "no such rowid: %lld", iRow);
+      rc = SQLITE_ERROR;
+    }else{
+      zErr = sqlite3MPrintf(p->db, "%s", sqlite3_errmsg(p->db));
+    }
+  }
+
+  assert( rc!=SQLITE_OK || zErr==0 );
+  assert( rc!=SQLITE_ROW && rc!=SQLITE_DONE );
+
+  *pzErr = zErr;
+  return rc;
+}
+
+/*
+** Open a blob handle.
+*/
+SQLITE_API int sqlite3_blob_open(
+  sqlite3* db,            /* The database connection */
+  const char *zDb,        /* The attached database containing the blob */
+  const char *zTable,     /* The table containing the blob */
+  const char *zColumn,    /* The column containing the blob */
+  sqlite_int64 iRow,      /* The row containing the glob */
+  int wrFlag,             /* True -> read/write access, false -> read-only */
+  sqlite3_blob **ppBlob   /* Handle for accessing the blob returned here */
+){
+  int nAttempt = 0;
+  int iCol;               /* Index of zColumn in row-record */
+  int rc = SQLITE_OK;
+  char *zErr = 0;
+  Table *pTab;
+  Incrblob *pBlob = 0;
+  Parse sParse;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppBlob==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  *ppBlob = 0;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zTable==0 || zColumn==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  wrFlag = !!wrFlag;                /* wrFlag = (wrFlag ? 1 : 0); */
+
+  sqlite3_mutex_enter(db->mutex);
+
+  pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
+  while(1){
+    sqlite3ParseObjectInit(&sParse,db);
+    if( !pBlob ) goto blob_open_out;
+    sqlite3DbFree(db, zErr);
+    zErr = 0;
+
+    sqlite3BtreeEnterAll(db);
+    pTab = sqlite3LocateTable(&sParse, 0, zTable, zDb);
+    if( pTab && IsVirtual(pTab) ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open virtual table: %s", zTable);
+    }
+    if( pTab && !HasRowid(pTab) ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open table without rowid: %s", zTable);
+    }
+    if( pTab && (pTab->tabFlags&TF_HasGenerated)!=0 ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open table with generated columns: %s",
+                      zTable);
+    }
+#ifndef SQLITE_OMIT_VIEW
+    if( pTab && IsView(pTab) ){
+      pTab = 0;
+      sqlite3ErrorMsg(&sParse, "cannot open view: %s", zTable);
+    }
+#endif
+    if( !pTab ){
+      if( sParse.zErrMsg ){
+        sqlite3DbFree(db, zErr);
+        zErr = sParse.zErrMsg;
+        sParse.zErrMsg = 0;
+      }
+      rc = SQLITE_ERROR;
+      sqlite3BtreeLeaveAll(db);
+      goto blob_open_out;
+    }
+    pBlob->pTab = pTab;
+    pBlob->zDb = db->aDb[sqlite3SchemaToIndex(db, pTab->pSchema)].zDbSName;
+
+    /* Now search pTab for the exact column. */
+    for(iCol=0; iCol<pTab->nCol; iCol++) {
+      if( sqlite3StrICmp(pTab->aCol[iCol].zCnName, zColumn)==0 ){
+        break;
+      }
+    }
+    if( iCol==pTab->nCol ){
+      sqlite3DbFree(db, zErr);
+      zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
+      rc = SQLITE_ERROR;
+      sqlite3BtreeLeaveAll(db);
+      goto blob_open_out;
+    }
+
+    /* If the value is being opened for writing, check that the
+    ** column is not indexed, and that it is not part of a foreign key.
+    */
+    if( wrFlag ){
+      const char *zFault = 0;
+      Index *pIdx;
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+      if( db->flags&SQLITE_ForeignKeys ){
+        /* Check that the column is not part of an FK child key definition. It
+        ** is not necessary to check if it is part of a parent key, as parent
+        ** key columns must be indexed. The check below will pick up this
+        ** case.  */
+        FKey *pFKey;
+        assert( IsOrdinaryTable(pTab) );
+        for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+          int j;
+          for(j=0; j<pFKey->nCol; j++){
+            if( pFKey->aCol[j].iFrom==iCol ){
+              zFault = "foreign key";
+            }
+          }
+        }
+      }
+#endif
+      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+        int j;
+        for(j=0; j<pIdx->nKeyCol; j++){
+          /* FIXME: Be smarter about indexes that use expressions */
+          if( pIdx->aiColumn[j]==iCol || pIdx->aiColumn[j]==XN_EXPR ){
+            zFault = "indexed";
+          }
+        }
+      }
+      if( zFault ){
+        sqlite3DbFree(db, zErr);
+        zErr = sqlite3MPrintf(db, "cannot open %s column for writing", zFault);
+        rc = SQLITE_ERROR;
+        sqlite3BtreeLeaveAll(db);
+        goto blob_open_out;
+      }
+    }
+
+    pBlob->pStmt = (sqlite3_stmt *)sqlite3VdbeCreate(&sParse);
+    assert( pBlob->pStmt || db->mallocFailed );
+    if( pBlob->pStmt ){
+
+      /* This VDBE program seeks a btree cursor to the identified
+      ** db/table/row entry. The reason for using a vdbe program instead
+      ** of writing code to use the b-tree layer directly is that the
+      ** vdbe program will take advantage of the various transaction,
+      ** locking and error handling infrastructure built into the vdbe.
+      **
+      ** After seeking the cursor, the vdbe executes an OP_ResultRow.
+      ** Code external to the Vdbe then "borrows" the b-tree cursor and
+      ** uses it to implement the blob_read(), blob_write() and
+      ** blob_bytes() functions.
+      **
+      ** The sqlite3_blob_close() function finalizes the vdbe program,
+      ** which closes the b-tree cursor and (possibly) commits the
+      ** transaction.
+      */
+      static const int iLn = VDBE_OFFSET_LINENO(2);
+      static const VdbeOpList openBlob[] = {
+        {OP_TableLock,      0, 0, 0},  /* 0: Acquire a read or write lock */
+        {OP_OpenRead,       0, 0, 0},  /* 1: Open a cursor */
+        /* blobSeekToRow() will initialize r[1] to the desired rowid */
+        {OP_NotExists,      0, 5, 1},  /* 2: Seek the cursor to rowid=r[1] */
+        {OP_Column,         0, 0, 1},  /* 3  */
+        {OP_ResultRow,      1, 0, 0},  /* 4  */
+        {OP_Halt,           0, 0, 0},  /* 5  */
+      };
+      Vdbe *v = (Vdbe *)pBlob->pStmt;
+      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      VdbeOp *aOp;
+
+      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, wrFlag,
+                           pTab->pSchema->schema_cookie,
+                           pTab->pSchema->iGeneration);
+      sqlite3VdbeChangeP5(v, 1);
+      assert( sqlite3VdbeCurrentAddr(v)==2 || db->mallocFailed );
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(openBlob), openBlob, iLn);
+
+      /* Make sure a mutex is held on the table to be accessed */
+      sqlite3VdbeUsesBtree(v, iDb);
+
+      if( db->mallocFailed==0 ){
+        assert( aOp!=0 );
+        /* Configure the OP_TableLock instruction */
+#ifdef SQLITE_OMIT_SHARED_CACHE
+        aOp[0].opcode = OP_Noop;
+#else
+        aOp[0].p1 = iDb;
+        aOp[0].p2 = pTab->tnum;
+        aOp[0].p3 = wrFlag;
+        sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
+      }
+      if( db->mallocFailed==0 ){
+#endif
+
+        /* Remove either the OP_OpenWrite or OpenRead. Set the P2
+        ** parameter of the other to pTab->tnum.  */
+        if( wrFlag ) aOp[1].opcode = OP_OpenWrite;
+        aOp[1].p2 = pTab->tnum;
+        aOp[1].p3 = iDb;
+
+        /* Configure the number of columns. Configure the cursor to
+        ** think that the table has one more column than it really
+        ** does. An OP_Column to retrieve this imaginary column will
+        ** always return an SQL NULL. This is useful because it means
+        ** we can invoke OP_Column to fill in the vdbe cursors type
+        ** and offset cache without causing any IO.
+        */
+        aOp[1].p4type = P4_INT32;
+        aOp[1].p4.i = pTab->nCol+1;
+        aOp[3].p2 = pTab->nCol;
+
+        sParse.nVar = 0;
+        sParse.nMem = 1;
+        sParse.nTab = 1;
+        sqlite3VdbeMakeReady(v, &sParse);
+      }
+    }
+
+    pBlob->iCol = iCol;
+    pBlob->db = db;
+    sqlite3BtreeLeaveAll(db);
+    if( db->mallocFailed ){
+      goto blob_open_out;
+    }
+    rc = blobSeekToRow(pBlob, iRow, &zErr);
+    if( (++nAttempt)>=SQLITE_MAX_SCHEMA_RETRY || rc!=SQLITE_SCHEMA ) break;
+    sqlite3ParseObjectReset(&sParse);
+  }
+
+blob_open_out:
+  if( rc==SQLITE_OK && db->mallocFailed==0 ){
+    *ppBlob = (sqlite3_blob *)pBlob;
+  }else{
+    if( pBlob && pBlob->pStmt ) sqlite3VdbeFinalize((Vdbe *)pBlob->pStmt);
+    sqlite3DbFree(db, pBlob);
+  }
+  sqlite3ErrorWithMsg(db, rc, (zErr ? "%s" : (char*)0), zErr);
+  sqlite3DbFree(db, zErr);
+  sqlite3ParseObjectReset(&sParse);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Close a blob handle that was previously created using
+** sqlite3_blob_open().
+*/
+SQLITE_API int sqlite3_blob_close(sqlite3_blob *pBlob){
+  Incrblob *p = (Incrblob *)pBlob;
+  int rc;
+  sqlite3 *db;
+
+  if( p ){
+    sqlite3_stmt *pStmt = p->pStmt;
+    db = p->db;
+    sqlite3_mutex_enter(db->mutex);
+    sqlite3DbFree(db, p);
+    sqlite3_mutex_leave(db->mutex);
+    rc = sqlite3_finalize(pStmt);
+  }else{
+    rc = SQLITE_OK;
+  }
+  return rc;
+}
+
+/*
+** Perform a read or write operation on a blob
+*/
+static int blobReadWrite(
+  sqlite3_blob *pBlob,
+  void *z,
+  int n,
+  int iOffset,
+  int (*xCall)(BtCursor*, u32, u32, void*)
+){
+  int rc;
+  Incrblob *p = (Incrblob *)pBlob;
+  Vdbe *v;
+  sqlite3 *db;
+
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+  db = p->db;
+  sqlite3_mutex_enter(db->mutex);
+  v = (Vdbe*)p->pStmt;
+
+  if( n<0 || iOffset<0 || ((sqlite3_int64)iOffset+n)>p->nByte ){
+    /* Request is out of range. Return a transient error. */
+    rc = SQLITE_ERROR;
+  }else if( v==0 ){
+    /* If there is no statement handle, then the blob-handle has
+    ** already been invalidated. Return SQLITE_ABORT in this case.
+    */
+    rc = SQLITE_ABORT;
+  }else{
+    /* Call either BtreeData() or BtreePutData(). If SQLITE_ABORT is
+    ** returned, clean-up the statement handle.
+    */
+    assert( db == v->db );
+    sqlite3BtreeEnterCursor(p->pCsr);
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    if( xCall==sqlite3BtreePutData && db->xPreUpdateCallback ){
+      /* If a pre-update hook is registered and this is a write cursor,
+      ** invoke it here.
+      **
+      ** TODO: The preupdate-hook is passed SQLITE_DELETE, even though this
+      ** operation should really be an SQLITE_UPDATE. This is probably
+      ** incorrect, but is convenient because at this point the new.* values
+      ** are not easily obtainable. And for the sessions module, an
+      ** SQLITE_UPDATE where the PK columns do not change is handled in the
+      ** same way as an SQLITE_DELETE (the SQLITE_DELETE code is actually
+      ** slightly more efficient). Since you cannot write to a PK column
+      ** using the incremental-blob API, this works. For the sessions module
+      ** anyhow.
+      */
+      sqlite3_int64 iKey;
+      iKey = sqlite3BtreeIntegerKey(p->pCsr);
+      assert( v->apCsr[0]!=0 );
+      assert( v->apCsr[0]->eCurType==CURTYPE_BTREE );
+      sqlite3VdbePreUpdateHook(
+          v, v->apCsr[0], SQLITE_DELETE, p->zDb, p->pTab, iKey, -1, p->iCol
+      );
+    }
+#endif
+
+    rc = xCall(p->pCsr, iOffset+p->iOffset, n, z);
+    sqlite3BtreeLeaveCursor(p->pCsr);
+    if( rc==SQLITE_ABORT ){
+      sqlite3VdbeFinalize(v);
+      p->pStmt = 0;
+    }else{
+      v->rc = rc;
+    }
+  }
+  sqlite3Error(db, rc);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Read data from a blob handle.
+*/
+SQLITE_API int sqlite3_blob_read(sqlite3_blob *pBlob, void *z, int n, int iOffset){
+  return blobReadWrite(pBlob, z, n, iOffset, sqlite3BtreePayloadChecked);
+}
+
+/*
+** Write data to a blob handle.
+*/
+SQLITE_API int sqlite3_blob_write(sqlite3_blob *pBlob, const void *z, int n, int iOffset){
+  return blobReadWrite(pBlob, (void *)z, n, iOffset, sqlite3BtreePutData);
+}
+
+/*
+** Query a blob handle for the size of the data.
+**
+** The Incrblob.nByte field is fixed for the lifetime of the Incrblob
+** so no mutex is required for access.
+*/
+SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *pBlob){
+  Incrblob *p = (Incrblob *)pBlob;
+  return (p && p->pStmt) ? p->nByte : 0;
+}
+
+/*
+** Move an existing blob handle to point to a different row of the same
+** database table.
+**
+** If an error occurs, or if the specified row does not exist or does not
+** contain a blob or text value, then an error code is returned and the
+** database handle error code and message set. If this happens, then all
+** subsequent calls to sqlite3_blob_xxx() functions (except blob_close())
+** immediately return SQLITE_ABORT.
+*/
+SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *pBlob, sqlite3_int64 iRow){
+  int rc;
+  Incrblob *p = (Incrblob *)pBlob;
+  sqlite3 *db;
+
+  if( p==0 ) return SQLITE_MISUSE_BKPT;
+  db = p->db;
+  sqlite3_mutex_enter(db->mutex);
+
+  if( p->pStmt==0 ){
+    /* If there is no statement handle, then the blob-handle has
+    ** already been invalidated. Return SQLITE_ABORT in this case.
+    */
+    rc = SQLITE_ABORT;
+  }else{
+    char *zErr;
+    ((Vdbe*)p->pStmt)->rc = SQLITE_OK;
+    rc = blobSeekToRow(p, iRow, &zErr);
+    if( rc!=SQLITE_OK ){
+      sqlite3ErrorWithMsg(db, rc, (zErr ? "%s" : (char*)0), zErr);
+      sqlite3DbFree(db, zErr);
+    }
+    assert( rc!=SQLITE_SCHEMA );
+  }
+
+  rc = sqlite3ApiExit(db, rc);
+  assert( rc==SQLITE_OK || p->pStmt==0 );
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+#endif /* #ifndef SQLITE_OMIT_INCRBLOB */
+
+/************** End of vdbeblob.c ********************************************/
+/************** Begin file vdbesort.c ****************************************/
+/*
+** 2011-07-09
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code for the VdbeSorter object, used in concert with
+** a VdbeCursor to sort large numbers of keys for CREATE INDEX statements
+** or by SELECT statements with ORDER BY clauses that cannot be satisfied
+** using indexes and without LIMIT clauses.
+**
+** The VdbeSorter object implements a multi-threaded external merge sort
+** algorithm that is efficient even if the number of elements being sorted
+** exceeds the available memory.
+**
+** Here is the (internal, non-API) interface between this module and the
+** rest of the SQLite system:
+**
+**    sqlite3VdbeSorterInit()       Create a new VdbeSorter object.
+**
+**    sqlite3VdbeSorterWrite()      Add a single new row to the VdbeSorter
+**                                  object.  The row is a binary blob in the
+**                                  OP_MakeRecord format that contains both
+**                                  the ORDER BY key columns and result columns
+**                                  in the case of a SELECT w/ ORDER BY, or
+**                                  the complete record for an index entry
+**                                  in the case of a CREATE INDEX.
+**
+**    sqlite3VdbeSorterRewind()     Sort all content previously added.
+**                                  Position the read cursor on the
+**                                  first sorted element.
+**
+**    sqlite3VdbeSorterNext()       Advance the read cursor to the next sorted
+**                                  element.
+**
+**    sqlite3VdbeSorterRowkey()     Return the complete binary blob for the
+**                                  row currently under the read cursor.
+**
+**    sqlite3VdbeSorterCompare()    Compare the binary blob for the row
+**                                  currently under the read cursor against
+**                                  another binary blob X and report if
+**                                  X is strictly less than the read cursor.
+**                                  Used to enforce uniqueness in a
+**                                  CREATE UNIQUE INDEX statement.
+**
+**    sqlite3VdbeSorterClose()      Close the VdbeSorter object and reclaim
+**                                  all resources.
+**
+**    sqlite3VdbeSorterReset()      Refurbish the VdbeSorter for reuse.  This
+**                                  is like Close() followed by Init() only
+**                                  much faster.
+**
+** The interfaces above must be called in a particular order.  Write() can
+** only occur in between Init()/Reset() and Rewind().  Next(), Rowkey(), and
+** Compare() can only occur in between Rewind() and Close()/Reset(). i.e.
+**
+**   Init()
+**   for each record: Write()
+**   Rewind()
+**     Rowkey()/Compare()
+**   Next()
+**   Close()
+**
+** Algorithm:
+**
+** Records passed to the sorter via calls to Write() are initially held
+** unsorted in main memory. Assuming the amount of memory used never exceeds
+** a threshold, when Rewind() is called the set of records is sorted using
+** an in-memory merge sort. In this case, no temporary files are required
+** and subsequent calls to Rowkey(), Next() and Compare() read records
+** directly from main memory.
+**
+** If the amount of space used to store records in main memory exceeds the
+** threshold, then the set of records currently in memory are sorted and
+** written to a temporary file in "Packed Memory Array" (PMA) format.
+** A PMA created at this point is known as a "level-0 PMA". Higher levels
+** of PMAs may be created by merging existing PMAs together - for example
+** merging two or more level-0 PMAs together creates a level-1 PMA.
+**
+** The threshold for the amount of main memory to use before flushing
+** records to a PMA is roughly the same as the limit configured for the
+** page-cache of the main database. Specifically, the threshold is set to
+** the value returned by "PRAGMA main.page_size" multiplied by
+** that returned by "PRAGMA main.cache_size", in bytes.
+**
+** If the sorter is running in single-threaded mode, then all PMAs generated
+** are appended to a single temporary file. Or, if the sorter is running in
+** multi-threaded mode then up to (N+1) temporary files may be opened, where
+** N is the configured number of worker threads. In this case, instead of
+** sorting the records and writing the PMA to a temporary file itself, the
+** calling thread usually launches a worker thread to do so. Except, if
+** there are already N worker threads running, the main thread does the work
+** itself.
+**
+** The sorter is running in multi-threaded mode if (a) the library was built
+** with pre-processor symbol SQLITE_MAX_WORKER_THREADS set to a value greater
+** than zero, and (b) worker threads have been enabled at runtime by calling
+** "PRAGMA threads=N" with some value of N greater than 0.
+**
+** When Rewind() is called, any data remaining in memory is flushed to a
+** final PMA. So at this point the data is stored in some number of sorted
+** PMAs within temporary files on disk.
+**
+** If there are fewer than SORTER_MAX_MERGE_COUNT PMAs in total and the
+** sorter is running in single-threaded mode, then these PMAs are merged
+** incrementally as keys are retrieved from the sorter by the VDBE.  The
+** MergeEngine object, described in further detail below, performs this
+** merge.
+**
+** Or, if running in multi-threaded mode, then a background thread is
+** launched to merge the existing PMAs. Once the background thread has
+** merged T bytes of data into a single sorted PMA, the main thread
+** begins reading keys from that PMA while the background thread proceeds
+** with merging the next T bytes of data. And so on.
+**
+** Parameter T is set to half the value of the memory threshold used
+** by Write() above to determine when to create a new PMA.
+**
+** If there are more than SORTER_MAX_MERGE_COUNT PMAs in total when
+** Rewind() is called, then a hierarchy of incremental-merges is used.
+** First, T bytes of data from the first SORTER_MAX_MERGE_COUNT PMAs on
+** disk are merged together. Then T bytes of data from the second set, and
+** so on, such that no operation ever merges more than SORTER_MAX_MERGE_COUNT
+** PMAs at a time. This done is to improve locality.
+**
+** If running in multi-threaded mode and there are more than
+** SORTER_MAX_MERGE_COUNT PMAs on disk when Rewind() is called, then more
+** than one background thread may be created. Specifically, there may be
+** one background thread for each temporary file on disk, and one background
+** thread to merge the output of each of the others to a single PMA for
+** the main thread to read from.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+/*
+** If SQLITE_DEBUG_SORTER_THREADS is defined, this module outputs various
+** messages to stderr that may be helpful in understanding the performance
+** characteristics of the sorter in multi-threaded mode.
+*/
+#if 0
+# define SQLITE_DEBUG_SORTER_THREADS 1
+#endif
+
+/*
+** Hard-coded maximum amount of data to accumulate in memory before flushing
+** to a level 0 PMA. The purpose of this limit is to prevent various integer
+** overflows. 512MiB.
+*/
+#define SQLITE_MAX_PMASZ    (1<<29)
+
+/*
+** Private objects used by the sorter
+*/
+typedef struct MergeEngine MergeEngine;     /* Merge PMAs together */
+typedef struct PmaReader PmaReader;         /* Incrementally read one PMA */
+typedef struct PmaWriter PmaWriter;         /* Incrementally write one PMA */
+typedef struct SorterRecord SorterRecord;   /* A record being sorted */
+typedef struct SortSubtask SortSubtask;     /* A sub-task in the sort process */
+typedef struct SorterFile SorterFile;       /* Temporary file object wrapper */
+typedef struct SorterList SorterList;       /* In-memory list of records */
+typedef struct IncrMerger IncrMerger;       /* Read & merge multiple PMAs */
+
+/*
+** A container for a temp file handle and the current amount of data
+** stored in the file.
+*/
+struct SorterFile {
+  sqlite3_file *pFd;              /* File handle */
+  i64 iEof;                       /* Bytes of data stored in pFd */
+};
+
+/*
+** An in-memory list of objects to be sorted.
+**
+** If aMemory==0 then each object is allocated separately and the objects
+** are connected using SorterRecord.u.pNext.  If aMemory!=0 then all objects
+** are stored in the aMemory[] bulk memory, one right after the other, and
+** are connected using SorterRecord.u.iNext.
+*/
+struct SorterList {
+  SorterRecord *pList;            /* Linked list of records */
+  u8 *aMemory;                    /* If non-NULL, bulk memory to hold pList */
+  i64 szPMA;                      /* Size of pList as PMA in bytes */
+};
+
+/*
+** The MergeEngine object is used to combine two or more smaller PMAs into
+** one big PMA using a merge operation.  Separate PMAs all need to be
+** combined into one big PMA in order to be able to step through the sorted
+** records in order.
+**
+** The aReadr[] array contains a PmaReader object for each of the PMAs being
+** merged.  An aReadr[] object either points to a valid key or else is at EOF.
+** ("EOF" means "End Of File".  When aReadr[] is at EOF there is no more data.)
+** For the purposes of the paragraphs below, we assume that the array is
+** actually N elements in size, where N is the smallest power of 2 greater
+** to or equal to the number of PMAs being merged. The extra aReadr[] elements
+** are treated as if they are empty (always at EOF).
+**
+** The aTree[] array is also N elements in size. The value of N is stored in
+** the MergeEngine.nTree variable.
+**
+** The final (N/2) elements of aTree[] contain the results of comparing
+** pairs of PMA keys together. Element i contains the result of
+** comparing aReadr[2*i-N] and aReadr[2*i-N+1]. Whichever key is smaller, the
+** aTree element is set to the index of it.
+**
+** For the purposes of this comparison, EOF is considered greater than any
+** other key value. If the keys are equal (only possible with two EOF
+** values), it doesn't matter which index is stored.
+**
+** The (N/4) elements of aTree[] that precede the final (N/2) described
+** above contains the index of the smallest of each block of 4 PmaReaders
+** And so on. So that aTree[1] contains the index of the PmaReader that
+** currently points to the smallest key value. aTree[0] is unused.
+**
+** Example:
+**
+**     aReadr[0] -> Banana
+**     aReadr[1] -> Feijoa
+**     aReadr[2] -> Elderberry
+**     aReadr[3] -> Currant
+**     aReadr[4] -> Grapefruit
+**     aReadr[5] -> Apple
+**     aReadr[6] -> Durian
+**     aReadr[7] -> EOF
+**
+**     aTree[] = { X, 5   0, 5    0, 3, 5, 6 }
+**
+** The current element is "Apple" (the value of the key indicated by
+** PmaReader 5). When the Next() operation is invoked, PmaReader 5 will
+** be advanced to the next key in its segment. Say the next key is
+** "Eggplant":
+**
+**     aReadr[5] -> Eggplant
+**
+** The contents of aTree[] are updated first by comparing the new PmaReader
+** 5 key to the current key of PmaReader 4 (still "Grapefruit"). The PmaReader
+** 5 value is still smaller, so aTree[6] is set to 5. And so on up the tree.
+** The value of PmaReader 6 - "Durian" - is now smaller than that of PmaReader
+** 5, so aTree[3] is set to 6. Key 0 is smaller than key 6 (Banana<Durian),
+** so the value written into element 1 of the array is 0. As follows:
+**
+**     aTree[] = { X, 0   0, 6    0, 3, 5, 6 }
+**
+** In other words, each time we advance to the next sorter element, log2(N)
+** key comparison operations are required, where N is the number of segments
+** being merged (rounded up to the next power of 2).
+*/
+struct MergeEngine {
+  int nTree;                 /* Used size of aTree/aReadr (power of 2) */
+  SortSubtask *pTask;        /* Used by this thread only */
+  int *aTree;                /* Current state of incremental merge */
+  PmaReader *aReadr;         /* Array of PmaReaders to merge data from */
+};
+
+/*
+** This object represents a single thread of control in a sort operation.
+** Exactly VdbeSorter.nTask instances of this object are allocated
+** as part of each VdbeSorter object. Instances are never allocated any
+** other way. VdbeSorter.nTask is set to the number of worker threads allowed
+** (see SQLITE_CONFIG_WORKER_THREADS) plus one (the main thread).  Thus for
+** single-threaded operation, there is exactly one instance of this object
+** and for multi-threaded operation there are two or more instances.
+**
+** Essentially, this structure contains all those fields of the VdbeSorter
+** structure for which each thread requires a separate instance. For example,
+** each thread requeries its own UnpackedRecord object to unpack records in
+** as part of comparison operations.
+**
+** Before a background thread is launched, variable bDone is set to 0. Then,
+** right before it exits, the thread itself sets bDone to 1. This is used for
+** two purposes:
+**
+**   1. When flushing the contents of memory to a level-0 PMA on disk, to
+**      attempt to select a SortSubtask for which there is not already an
+**      active background thread (since doing so causes the main thread
+**      to block until it finishes).
+**
+**   2. If SQLITE_DEBUG_SORTER_THREADS is defined, to determine if a call
+**      to sqlite3ThreadJoin() is likely to block. Cases that are likely to
+**      block provoke debugging output.
+**
+** In both cases, the effects of the main thread seeing (bDone==0) even
+** after the thread has finished are not dire. So we don't worry about
+** memory barriers and such here.
+*/
+typedef int (*SorterCompare)(SortSubtask*,int*,const void*,int,const void*,int);
+struct SortSubtask {
+  SQLiteThread *pThread;          /* Background thread, if any */
+  int bDone;                      /* Set if thread is finished but not joined */
+  int nPMA;                       /* Number of PMAs currently in file */
+  VdbeSorter *pSorter;            /* Sorter that owns this sub-task */
+  UnpackedRecord *pUnpacked;      /* Space to unpack a record */
+  SorterList list;                /* List for thread to write to a PMA */
+  SorterCompare xCompare;         /* Compare function to use */
+  SorterFile file;                /* Temp file for level-0 PMAs */
+  SorterFile file2;               /* Space for other PMAs */
+};
+
+
+/*
+** Main sorter structure. A single instance of this is allocated for each
+** sorter cursor created by the VDBE.
+**
+** mxKeysize:
+**   As records are added to the sorter by calls to sqlite3VdbeSorterWrite(),
+**   this variable is updated so as to be set to the size on disk of the
+**   largest record in the sorter.
+*/
+struct VdbeSorter {
+  int mnPmaSize;                  /* Minimum PMA size, in bytes */
+  int mxPmaSize;                  /* Maximum PMA size, in bytes.  0==no limit */
+  int mxKeysize;                  /* Largest serialized key seen so far */
+  int pgsz;                       /* Main database page size */
+  PmaReader *pReader;             /* Readr data from here after Rewind() */
+  MergeEngine *pMerger;           /* Or here, if bUseThreads==0 */
+  sqlite3 *db;                    /* Database connection */
+  KeyInfo *pKeyInfo;              /* How to compare records */
+  UnpackedRecord *pUnpacked;      /* Used by VdbeSorterCompare() */
+  SorterList list;                /* List of in-memory records */
+  int iMemory;                    /* Offset of free space in list.aMemory */
+  int nMemory;                    /* Size of list.aMemory allocation in bytes */
+  u8 bUsePMA;                     /* True if one or more PMAs created */
+  u8 bUseThreads;                 /* True to use background threads */
+  u8 iPrev;                       /* Previous thread used to flush PMA */
+  u8 nTask;                       /* Size of aTask[] array */
+  u8 typeMask;
+  SortSubtask aTask[1];           /* One or more subtasks */
+};
+
+#define SORTER_TYPE_INTEGER 0x01
+#define SORTER_TYPE_TEXT    0x02
+
+/*
+** An instance of the following object is used to read records out of a
+** PMA, in sorted order.  The next key to be read is cached in nKey/aKey.
+** aKey might point into aMap or into aBuffer.  If neither of those locations
+** contain a contiguous representation of the key, then aAlloc is allocated
+** and the key is copied into aAlloc and aKey is made to point to aAlloc.
+**
+** pFd==0 at EOF.
+*/
+struct PmaReader {
+  i64 iReadOff;               /* Current read offset */
+  i64 iEof;                   /* 1 byte past EOF for this PmaReader */
+  int nAlloc;                 /* Bytes of space at aAlloc */
+  int nKey;                   /* Number of bytes in key */
+  sqlite3_file *pFd;          /* File handle we are reading from */
+  u8 *aAlloc;                 /* Space for aKey if aBuffer and pMap wont work */
+  u8 *aKey;                   /* Pointer to current key */
+  u8 *aBuffer;                /* Current read buffer */
+  int nBuffer;                /* Size of read buffer in bytes */
+  u8 *aMap;                   /* Pointer to mapping of entire file */
+  IncrMerger *pIncr;          /* Incremental merger */
+};
+
+/*
+** Normally, a PmaReader object iterates through an existing PMA stored
+** within a temp file. However, if the PmaReader.pIncr variable points to
+** an object of the following type, it may be used to iterate/merge through
+** multiple PMAs simultaneously.
+**
+** There are two types of IncrMerger object - single (bUseThread==0) and
+** multi-threaded (bUseThread==1).
+**
+** A multi-threaded IncrMerger object uses two temporary files - aFile[0]
+** and aFile[1]. Neither file is allowed to grow to more than mxSz bytes in
+** size. When the IncrMerger is initialized, it reads enough data from
+** pMerger to populate aFile[0]. It then sets variables within the
+** corresponding PmaReader object to read from that file and kicks off
+** a background thread to populate aFile[1] with the next mxSz bytes of
+** sorted record data from pMerger.
+**
+** When the PmaReader reaches the end of aFile[0], it blocks until the
+** background thread has finished populating aFile[1]. It then exchanges
+** the contents of the aFile[0] and aFile[1] variables within this structure,
+** sets the PmaReader fields to read from the new aFile[0] and kicks off
+** another background thread to populate the new aFile[1]. And so on, until
+** the contents of pMerger are exhausted.
+**
+** A single-threaded IncrMerger does not open any temporary files of its
+** own. Instead, it has exclusive access to mxSz bytes of space beginning
+** at offset iStartOff of file pTask->file2. And instead of using a
+** background thread to prepare data for the PmaReader, with a single
+** threaded IncrMerger the allocate part of pTask->file2 is "refilled" with
+** keys from pMerger by the calling thread whenever the PmaReader runs out
+** of data.
+*/
+struct IncrMerger {
+  SortSubtask *pTask;             /* Task that owns this merger */
+  MergeEngine *pMerger;           /* Merge engine thread reads data from */
+  i64 iStartOff;                  /* Offset to start writing file at */
+  int mxSz;                       /* Maximum bytes of data to store */
+  int bEof;                       /* Set to true when merge is finished */
+  int bUseThread;                 /* True to use a bg thread for this object */
+  SorterFile aFile[2];            /* aFile[0] for reading, [1] for writing */
+};
+
+/*
+** An instance of this object is used for writing a PMA.
+**
+** The PMA is written one record at a time.  Each record is of an arbitrary
+** size.  But I/O is more efficient if it occurs in page-sized blocks where
+** each block is aligned on a page boundary.  This object caches writes to
+** the PMA so that aligned, page-size blocks are written.
+*/
+struct PmaWriter {
+  int eFWErr;                     /* Non-zero if in an error state */
+  u8 *aBuffer;                    /* Pointer to write buffer */
+  int nBuffer;                    /* Size of write buffer in bytes */
+  int iBufStart;                  /* First byte of buffer to write */
+  int iBufEnd;                    /* Last byte of buffer to write */
+  i64 iWriteOff;                  /* Offset of start of buffer in file */
+  sqlite3_file *pFd;              /* File handle to write to */
+};
+
+/*
+** This object is the header on a single record while that record is being
+** held in memory and prior to being written out as part of a PMA.
+**
+** How the linked list is connected depends on how memory is being managed
+** by this module. If using a separate allocation for each in-memory record
+** (VdbeSorter.list.aMemory==0), then the list is always connected using the
+** SorterRecord.u.pNext pointers.
+**
+** Or, if using the single large allocation method (VdbeSorter.list.aMemory!=0),
+** then while records are being accumulated the list is linked using the
+** SorterRecord.u.iNext offset. This is because the aMemory[] array may
+** be sqlite3Realloc()ed while records are being accumulated. Once the VM
+** has finished passing records to the sorter, or when the in-memory buffer
+** is full, the list is sorted. As part of the sorting process, it is
+** converted to use the SorterRecord.u.pNext pointers. See function
+** vdbeSorterSort() for details.
+*/
+struct SorterRecord {
+  int nVal;                       /* Size of the record in bytes */
+  union {
+    SorterRecord *pNext;          /* Pointer to next record in list */
+    int iNext;                    /* Offset within aMemory of next record */
+  } u;
+  /* The data for the record immediately follows this header */
+};
+
+/* Return a pointer to the buffer containing the record data for SorterRecord
+** object p. Should be used as if:
+**
+**   void *SRVAL(SorterRecord *p) { return (void*)&p[1]; }
+*/
+#define SRVAL(p) ((void*)((SorterRecord*)(p) + 1))
+
+
+/* Maximum number of PMAs that a single MergeEngine can merge */
+#define SORTER_MAX_MERGE_COUNT 16
+
+static int vdbeIncrSwap(IncrMerger*);
+static void vdbeIncrFree(IncrMerger *);
+
+/*
+** Free all memory belonging to the PmaReader object passed as the
+** argument. All structure fields are set to zero before returning.
+*/
+static void vdbePmaReaderClear(PmaReader *pReadr){
+  sqlite3_free(pReadr->aAlloc);
+  sqlite3_free(pReadr->aBuffer);
+  if( pReadr->aMap ) sqlite3OsUnfetch(pReadr->pFd, 0, pReadr->aMap);
+  vdbeIncrFree(pReadr->pIncr);
+  memset(pReadr, 0, sizeof(PmaReader));
+}
+
+/*
+** Read the next nByte bytes of data from the PMA p.
+** If successful, set *ppOut to point to a buffer containing the data
+** and return SQLITE_OK. Otherwise, if an error occurs, return an SQLite
+** error code.
+**
+** The buffer returned in *ppOut is only valid until the
+** next call to this function.
+*/
+static int vdbePmaReadBlob(
+  PmaReader *p,                   /* PmaReader from which to take the blob */
+  int nByte,                      /* Bytes of data to read */
+  u8 **ppOut                      /* OUT: Pointer to buffer containing data */
+){
+  int iBuf;                       /* Offset within buffer to read from */
+  int nAvail;                     /* Bytes of data available in buffer */
+
+  if( p->aMap ){
+    *ppOut = &p->aMap[p->iReadOff];
+    p->iReadOff += nByte;
+    return SQLITE_OK;
+  }
+
+  assert( p->aBuffer );
+
+  /* If there is no more data to be read from the buffer, read the next
+  ** p->nBuffer bytes of data from the file into it. Or, if there are less
+  ** than p->nBuffer bytes remaining in the PMA, read all remaining data.  */
+  iBuf = p->iReadOff % p->nBuffer;
+  if( iBuf==0 ){
+    int nRead;                    /* Bytes to read from disk */
+    int rc;                       /* sqlite3OsRead() return code */
+
+    /* Determine how many bytes of data to read. */
+    if( (p->iEof - p->iReadOff) > (i64)p->nBuffer ){
+      nRead = p->nBuffer;
+    }else{
+      nRead = (int)(p->iEof - p->iReadOff);
+    }
+    assert( nRead>0 );
+
+    /* Readr data from the file. Return early if an error occurs. */
+    rc = sqlite3OsRead(p->pFd, p->aBuffer, nRead, p->iReadOff);
+    assert( rc!=SQLITE_IOERR_SHORT_READ );
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  nAvail = p->nBuffer - iBuf;
+
+  if( nByte<=nAvail ){
+    /* The requested data is available in the in-memory buffer. In this
+    ** case there is no need to make a copy of the data, just return a
+    ** pointer into the buffer to the caller.  */
+    *ppOut = &p->aBuffer[iBuf];
+    p->iReadOff += nByte;
+  }else{
+    /* The requested data is not all available in the in-memory buffer.
+    ** In this case, allocate space at p->aAlloc[] to copy the requested
+    ** range into. Then return a copy of pointer p->aAlloc to the caller.  */
+    int nRem;                     /* Bytes remaining to copy */
+
+    /* Extend the p->aAlloc[] allocation if required. */
+    if( p->nAlloc<nByte ){
+      u8 *aNew;
+      sqlite3_int64 nNew = MAX(128, 2*(sqlite3_int64)p->nAlloc);
+      while( nByte>nNew ) nNew = nNew*2;
+      aNew = sqlite3Realloc(p->aAlloc, nNew);
+      if( !aNew ) return SQLITE_NOMEM_BKPT;
+      p->nAlloc = nNew;
+      p->aAlloc = aNew;
+    }
+
+    /* Copy as much data as is available in the buffer into the start of
+    ** p->aAlloc[].  */
+    memcpy(p->aAlloc, &p->aBuffer[iBuf], nAvail);
+    p->iReadOff += nAvail;
+    nRem = nByte - nAvail;
+
+    /* The following loop copies up to p->nBuffer bytes per iteration into
+    ** the p->aAlloc[] buffer.  */
+    while( nRem>0 ){
+      int rc;                     /* vdbePmaReadBlob() return code */
+      int nCopy;                  /* Number of bytes to copy */
+      u8 *aNext = 0;              /* Pointer to buffer to copy data from */
+
+      nCopy = nRem;
+      if( nRem>p->nBuffer ) nCopy = p->nBuffer;
+      rc = vdbePmaReadBlob(p, nCopy, &aNext);
+      if( rc!=SQLITE_OK ) return rc;
+      assert( aNext!=p->aAlloc );
+      assert( aNext!=0 );
+      memcpy(&p->aAlloc[nByte - nRem], aNext, nCopy);
+      nRem -= nCopy;
+    }
+
+    *ppOut = p->aAlloc;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Read a varint from the stream of data accessed by p. Set *pnOut to
+** the value read.
+*/
+static int vdbePmaReadVarint(PmaReader *p, u64 *pnOut){
+  int iBuf;
+
+  if( p->aMap ){
+    p->iReadOff += sqlite3GetVarint(&p->aMap[p->iReadOff], pnOut);
+  }else{
+    iBuf = p->iReadOff % p->nBuffer;
+    if( iBuf && (p->nBuffer-iBuf)>=9 ){
+      p->iReadOff += sqlite3GetVarint(&p->aBuffer[iBuf], pnOut);
+    }else{
+      u8 aVarint[16], *a;
+      int i = 0, rc;
+      do{
+        rc = vdbePmaReadBlob(p, 1, &a);
+        if( rc ) return rc;
+        aVarint[(i++)&0xf] = a[0];
+      }while( (a[0]&0x80)!=0 );
+      sqlite3GetVarint(aVarint, pnOut);
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Attempt to memory map file pFile. If successful, set *pp to point to the
+** new mapping and return SQLITE_OK. If the mapping is not attempted
+** (because the file is too large or the VFS layer is configured not to use
+** mmap), return SQLITE_OK and set *pp to NULL.
+**
+** Or, if an error occurs, return an SQLite error code. The final value of
+** *pp is undefined in this case.
+*/
+static int vdbeSorterMapFile(SortSubtask *pTask, SorterFile *pFile, u8 **pp){
+  int rc = SQLITE_OK;
+  if( pFile->iEof<=(i64)(pTask->pSorter->db->nMaxSorterMmap) ){
+    sqlite3_file *pFd = pFile->pFd;
+    if( pFd->pMethods->iVersion>=3 ){
+      rc = sqlite3OsFetch(pFd, 0, (int)pFile->iEof, (void**)pp);
+      testcase( rc!=SQLITE_OK );
+    }
+  }
+  return rc;
+}
+
+/*
+** Attach PmaReader pReadr to file pFile (if it is not already attached to
+** that file) and seek it to offset iOff within the file.  Return SQLITE_OK
+** if successful, or an SQLite error code if an error occurs.
+*/
+static int vdbePmaReaderSeek(
+  SortSubtask *pTask,             /* Task context */
+  PmaReader *pReadr,              /* Reader whose cursor is to be moved */
+  SorterFile *pFile,              /* Sorter file to read from */
+  i64 iOff                        /* Offset in pFile */
+){
+  int rc = SQLITE_OK;
+
+  assert( pReadr->pIncr==0 || pReadr->pIncr->bEof==0 );
+
+  if( sqlite3FaultSim(201) ) return SQLITE_IOERR_READ;
+  if( pReadr->aMap ){
+    sqlite3OsUnfetch(pReadr->pFd, 0, pReadr->aMap);
+    pReadr->aMap = 0;
+  }
+  pReadr->iReadOff = iOff;
+  pReadr->iEof = pFile->iEof;
+  pReadr->pFd = pFile->pFd;
+
+  rc = vdbeSorterMapFile(pTask, pFile, &pReadr->aMap);
+  if( rc==SQLITE_OK && pReadr->aMap==0 ){
+    int pgsz = pTask->pSorter->pgsz;
+    int iBuf = pReadr->iReadOff % pgsz;
+    if( pReadr->aBuffer==0 ){
+      pReadr->aBuffer = (u8*)sqlite3Malloc(pgsz);
+      if( pReadr->aBuffer==0 ) rc = SQLITE_NOMEM_BKPT;
+      pReadr->nBuffer = pgsz;
+    }
+    if( rc==SQLITE_OK && iBuf ){
+      int nRead = pgsz - iBuf;
+      if( (pReadr->iReadOff + nRead) > pReadr->iEof ){
+        nRead = (int)(pReadr->iEof - pReadr->iReadOff);
+      }
+      rc = sqlite3OsRead(
+          pReadr->pFd, &pReadr->aBuffer[iBuf], nRead, pReadr->iReadOff
+      );
+      testcase( rc!=SQLITE_OK );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Advance PmaReader pReadr to the next key in its PMA. Return SQLITE_OK if
+** no error occurs, or an SQLite error code if one does.
+*/
+static int vdbePmaReaderNext(PmaReader *pReadr){
+  int rc = SQLITE_OK;             /* Return Code */
+  u64 nRec = 0;                   /* Size of record in bytes */
+
+
+  if( pReadr->iReadOff>=pReadr->iEof ){
+    IncrMerger *pIncr = pReadr->pIncr;
+    int bEof = 1;
+    if( pIncr ){
+      rc = vdbeIncrSwap(pIncr);
+      if( rc==SQLITE_OK && pIncr->bEof==0 ){
+        rc = vdbePmaReaderSeek(
+            pIncr->pTask, pReadr, &pIncr->aFile[0], pIncr->iStartOff
+        );
+        bEof = 0;
+      }
+    }
+
+    if( bEof ){
+      /* This is an EOF condition */
+      vdbePmaReaderClear(pReadr);
+      testcase( rc!=SQLITE_OK );
+      return rc;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = vdbePmaReadVarint(pReadr, &nRec);
+  }
+  if( rc==SQLITE_OK ){
+    pReadr->nKey = (int)nRec;
+    rc = vdbePmaReadBlob(pReadr, (int)nRec, &pReadr->aKey);
+    testcase( rc!=SQLITE_OK );
+  }
+
+  return rc;
+}
+
+/*
+** Initialize PmaReader pReadr to scan through the PMA stored in file pFile
+** starting at offset iStart and ending at offset iEof-1. This function
+** leaves the PmaReader pointing to the first key in the PMA (or EOF if the
+** PMA is empty).
+**
+** If the pnByte parameter is NULL, then it is assumed that the file
+** contains a single PMA, and that that PMA omits the initial length varint.
+*/
+static int vdbePmaReaderInit(
+  SortSubtask *pTask,             /* Task context */
+  SorterFile *pFile,              /* Sorter file to read from */
+  i64 iStart,                     /* Start offset in pFile */
+  PmaReader *pReadr,              /* PmaReader to populate */
+  i64 *pnByte                     /* IN/OUT: Increment this value by PMA size */
+){
+  int rc;
+
+  assert( pFile->iEof>iStart );
+  assert( pReadr->aAlloc==0 && pReadr->nAlloc==0 );
+  assert( pReadr->aBuffer==0 );
+  assert( pReadr->aMap==0 );
+
+  rc = vdbePmaReaderSeek(pTask, pReadr, pFile, iStart);
+  if( rc==SQLITE_OK ){
+    u64 nByte = 0;                 /* Size of PMA in bytes */
+    rc = vdbePmaReadVarint(pReadr, &nByte);
+    pReadr->iEof = pReadr->iReadOff + nByte;
+    *pnByte += nByte;
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = vdbePmaReaderNext(pReadr);
+  }
+  return rc;
+}
+
+/*
+** A version of vdbeSorterCompare() that assumes that it has already been
+** determined that the first field of key1 is equal to the first field of
+** key2.
+*/
+static int vdbeSorterCompareTail(
+  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
+  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
+  const void *pKey1, int nKey1,   /* Left side of comparison */
+  const void *pKey2, int nKey2    /* Right side of comparison */
+){
+  UnpackedRecord *r2 = pTask->pUnpacked;
+  if( *pbKey2Cached==0 ){
+    sqlite3VdbeRecordUnpack(pTask->pSorter->pKeyInfo, nKey2, pKey2, r2);
+    *pbKey2Cached = 1;
+  }
+  return sqlite3VdbeRecordCompareWithSkip(nKey1, pKey1, r2, 1);
+}
+
+/*
+** Compare key1 (buffer pKey1, size nKey1 bytes) with key2 (buffer pKey2,
+** size nKey2 bytes). Use (pTask->pKeyInfo) for the collation sequences
+** used by the comparison. Return the result of the comparison.
+**
+** If IN/OUT parameter *pbKey2Cached is true when this function is called,
+** it is assumed that (pTask->pUnpacked) contains the unpacked version
+** of key2. If it is false, (pTask->pUnpacked) is populated with the unpacked
+** version of key2 and *pbKey2Cached set to true before returning.
+**
+** If an OOM error is encountered, (pTask->pUnpacked->error_rc) is set
+** to SQLITE_NOMEM.
+*/
+static int vdbeSorterCompare(
+  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
+  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
+  const void *pKey1, int nKey1,   /* Left side of comparison */
+  const void *pKey2, int nKey2    /* Right side of comparison */
+){
+  UnpackedRecord *r2 = pTask->pUnpacked;
+  if( !*pbKey2Cached ){
+    sqlite3VdbeRecordUnpack(pTask->pSorter->pKeyInfo, nKey2, pKey2, r2);
+    *pbKey2Cached = 1;
+  }
+  return sqlite3VdbeRecordCompare(nKey1, pKey1, r2);
+}
+
+/*
+** A specially optimized version of vdbeSorterCompare() that assumes that
+** the first field of each key is a TEXT value and that the collation
+** sequence to compare them with is BINARY.
+*/
+static int vdbeSorterCompareText(
+  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
+  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
+  const void *pKey1, int nKey1,   /* Left side of comparison */
+  const void *pKey2, int nKey2    /* Right side of comparison */
+){
+  const u8 * const p1 = (const u8 * const)pKey1;
+  const u8 * const p2 = (const u8 * const)pKey2;
+  const u8 * const v1 = &p1[ p1[0] ];   /* Pointer to value 1 */
+  const u8 * const v2 = &p2[ p2[0] ];   /* Pointer to value 2 */
+
+  int n1;
+  int n2;
+  int res;
+
+  getVarint32NR(&p1[1], n1);
+  getVarint32NR(&p2[1], n2);
+  res = memcmp(v1, v2, (MIN(n1, n2) - 13)/2);
+  if( res==0 ){
+    res = n1 - n2;
+  }
+
+  if( res==0 ){
+    if( pTask->pSorter->pKeyInfo->nKeyField>1 ){
+      res = vdbeSorterCompareTail(
+          pTask, pbKey2Cached, pKey1, nKey1, pKey2, nKey2
+      );
+    }
+  }else{
+    assert( !(pTask->pSorter->pKeyInfo->aSortFlags[0]&KEYINFO_ORDER_BIGNULL) );
+    if( pTask->pSorter->pKeyInfo->aSortFlags[0] ){
+      res = res * -1;
+    }
+  }
+
+  return res;
+}
+
+/*
+** A specially optimized version of vdbeSorterCompare() that assumes that
+** the first field of each key is an INTEGER value.
+*/
+static int vdbeSorterCompareInt(
+  SortSubtask *pTask,             /* Subtask context (for pKeyInfo) */
+  int *pbKey2Cached,              /* True if pTask->pUnpacked is pKey2 */
+  const void *pKey1, int nKey1,   /* Left side of comparison */
+  const void *pKey2, int nKey2    /* Right side of comparison */
+){
+  const u8 * const p1 = (const u8 * const)pKey1;
+  const u8 * const p2 = (const u8 * const)pKey2;
+  const int s1 = p1[1];                 /* Left hand serial type */
+  const int s2 = p2[1];                 /* Right hand serial type */
+  const u8 * const v1 = &p1[ p1[0] ];   /* Pointer to value 1 */
+  const u8 * const v2 = &p2[ p2[0] ];   /* Pointer to value 2 */
+  int res;                              /* Return value */
+
+  assert( (s1>0 && s1<7) || s1==8 || s1==9 );
+  assert( (s2>0 && s2<7) || s2==8 || s2==9 );
+
+  if( s1==s2 ){
+    /* The two values have the same sign. Compare using memcmp(). */
+    static const u8 aLen[] = {0, 1, 2, 3, 4, 6, 8, 0, 0, 0 };
+    const u8 n = aLen[s1];
+    int i;
+    res = 0;
+    for(i=0; i<n; i++){
+      if( (res = v1[i] - v2[i])!=0 ){
+        if( ((v1[0] ^ v2[0]) & 0x80)!=0 ){
+          res = v1[0] & 0x80 ? -1 : +1;
+        }
+        break;
+      }
+    }
+  }else if( s1>7 && s2>7 ){
+    res = s1 - s2;
+  }else{
+    if( s2>7 ){
+      res = +1;
+    }else if( s1>7 ){
+      res = -1;
+    }else{
+      res = s1 - s2;
+    }
+    assert( res!=0 );
+
+    if( res>0 ){
+      if( *v1 & 0x80 ) res = -1;
+    }else{
+      if( *v2 & 0x80 ) res = +1;
+    }
+  }
+
+  if( res==0 ){
+    if( pTask->pSorter->pKeyInfo->nKeyField>1 ){
+      res = vdbeSorterCompareTail(
+          pTask, pbKey2Cached, pKey1, nKey1, pKey2, nKey2
+      );
+    }
+  }else if( pTask->pSorter->pKeyInfo->aSortFlags[0] ){
+    assert( !(pTask->pSorter->pKeyInfo->aSortFlags[0]&KEYINFO_ORDER_BIGNULL) );
+    res = res * -1;
+  }
+
+  return res;
+}
+
+/*
+** Initialize the temporary index cursor just opened as a sorter cursor.
+**
+** Usually, the sorter module uses the value of (pCsr->pKeyInfo->nKeyField)
+** to determine the number of fields that should be compared from the
+** records being sorted. However, if the value passed as argument nField
+** is non-zero and the sorter is able to guarantee a stable sort, nField
+** is used instead. This is used when sorting records for a CREATE INDEX
+** statement. In this case, keys are always delivered to the sorter in
+** order of the primary key, which happens to be make up the final part
+** of the records being sorted. So if the sort is stable, there is never
+** any reason to compare PK fields and they can be ignored for a small
+** performance boost.
+**
+** The sorter can guarantee a stable sort when running in single-threaded
+** mode, but not in multi-threaded mode.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterInit(
+  sqlite3 *db,                    /* Database connection (for malloc()) */
+  int nField,                     /* Number of key fields in each record */
+  VdbeCursor *pCsr                /* Cursor that holds the new sorter */
+){
+  int pgsz;                       /* Page size of main database */
+  int i;                          /* Used to iterate through aTask[] */
+  VdbeSorter *pSorter;            /* The new sorter */
+  KeyInfo *pKeyInfo;              /* Copy of pCsr->pKeyInfo with db==0 */
+  int szKeyInfo;                  /* Size of pCsr->pKeyInfo in bytes */
+  int sz;                         /* Size of pSorter in bytes */
+  int rc = SQLITE_OK;
+#if SQLITE_MAX_WORKER_THREADS==0
+# define nWorker 0
+#else
+  int nWorker;
+#endif
+
+  /* Initialize the upper limit on the number of worker threads */
+#if SQLITE_MAX_WORKER_THREADS>0
+  if( sqlite3TempInMemory(db) || sqlite3GlobalConfig.bCoreMutex==0 ){
+    nWorker = 0;
+  }else{
+    nWorker = db->aLimit[SQLITE_LIMIT_WORKER_THREADS];
+  }
+#endif
+
+  /* Do not allow the total number of threads (main thread + all workers)
+  ** to exceed the maximum merge count */
+#if SQLITE_MAX_WORKER_THREADS>=SORTER_MAX_MERGE_COUNT
+  if( nWorker>=SORTER_MAX_MERGE_COUNT ){
+    nWorker = SORTER_MAX_MERGE_COUNT-1;
+  }
+#endif
+
+  assert( pCsr->pKeyInfo );
+  assert( !pCsr->isEphemeral );
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  szKeyInfo = sizeof(KeyInfo) + (pCsr->pKeyInfo->nKeyField-1)*sizeof(CollSeq*);
+  sz = sizeof(VdbeSorter) + nWorker * sizeof(SortSubtask);
+
+  pSorter = (VdbeSorter*)sqlite3DbMallocZero(db, sz + szKeyInfo);
+  pCsr->uc.pSorter = pSorter;
+  if( pSorter==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+  }else{
+    Btree *pBt = db->aDb[0].pBt;
+    pSorter->pKeyInfo = pKeyInfo = (KeyInfo*)((u8*)pSorter + sz);
+    memcpy(pKeyInfo, pCsr->pKeyInfo, szKeyInfo);
+    pKeyInfo->db = 0;
+    if( nField && nWorker==0 ){
+      pKeyInfo->nKeyField = nField;
+    }
+    sqlite3BtreeEnter(pBt);
+    pSorter->pgsz = pgsz = sqlite3BtreeGetPageSize(pBt);
+    sqlite3BtreeLeave(pBt);
+    pSorter->nTask = nWorker + 1;
+    pSorter->iPrev = (u8)(nWorker - 1);
+    pSorter->bUseThreads = (pSorter->nTask>1);
+    pSorter->db = db;
+    for(i=0; i<pSorter->nTask; i++){
+      SortSubtask *pTask = &pSorter->aTask[i];
+      pTask->pSorter = pSorter;
+    }
+
+    if( !sqlite3TempInMemory(db) ){
+      i64 mxCache;                /* Cache size in bytes*/
+      u32 szPma = sqlite3GlobalConfig.szPma;
+      pSorter->mnPmaSize = szPma * pgsz;
+
+      mxCache = db->aDb[0].pSchema->cache_size;
+      if( mxCache<0 ){
+        /* A negative cache-size value C indicates that the cache is abs(C)
+        ** KiB in size.  */
+        mxCache = mxCache * -1024;
+      }else{
+        mxCache = mxCache * pgsz;
+      }
+      mxCache = MIN(mxCache, SQLITE_MAX_PMASZ);
+      pSorter->mxPmaSize = MAX(pSorter->mnPmaSize, (int)mxCache);
+
+      /* Avoid large memory allocations if the application has requested
+      ** SQLITE_CONFIG_SMALL_MALLOC. */
+      if( sqlite3GlobalConfig.bSmallMalloc==0 ){
+        assert( pSorter->iMemory==0 );
+        pSorter->nMemory = pgsz;
+        pSorter->list.aMemory = (u8*)sqlite3Malloc(pgsz);
+        if( !pSorter->list.aMemory ) rc = SQLITE_NOMEM_BKPT;
+      }
+    }
+
+    if( pKeyInfo->nAllField<13
+     && (pKeyInfo->aColl[0]==0 || pKeyInfo->aColl[0]==db->pDfltColl)
+     && (pKeyInfo->aSortFlags[0] & KEYINFO_ORDER_BIGNULL)==0
+    ){
+      pSorter->typeMask = SORTER_TYPE_INTEGER | SORTER_TYPE_TEXT;
+    }
+  }
+
+  return rc;
+}
+#undef nWorker   /* Defined at the top of this function */
+
+/*
+** Free the list of sorted records starting at pRecord.
+*/
+static void vdbeSorterRecordFree(sqlite3 *db, SorterRecord *pRecord){
+  SorterRecord *p;
+  SorterRecord *pNext;
+  for(p=pRecord; p; p=pNext){
+    pNext = p->u.pNext;
+    sqlite3DbFree(db, p);
+  }
+}
+
+/*
+** Free all resources owned by the object indicated by argument pTask. All
+** fields of *pTask are zeroed before returning.
+*/
+static void vdbeSortSubtaskCleanup(sqlite3 *db, SortSubtask *pTask){
+  sqlite3DbFree(db, pTask->pUnpacked);
+#if SQLITE_MAX_WORKER_THREADS>0
+  /* pTask->list.aMemory can only be non-zero if it was handed memory
+  ** from the main thread.  That only occurs SQLITE_MAX_WORKER_THREADS>0 */
+  if( pTask->list.aMemory ){
+    sqlite3_free(pTask->list.aMemory);
+  }else
+#endif
+  {
+    assert( pTask->list.aMemory==0 );
+    vdbeSorterRecordFree(0, pTask->list.pList);
+  }
+  if( pTask->file.pFd ){
+    sqlite3OsCloseFree(pTask->file.pFd);
+  }
+  if( pTask->file2.pFd ){
+    sqlite3OsCloseFree(pTask->file2.pFd);
+  }
+  memset(pTask, 0, sizeof(SortSubtask));
+}
+
+#ifdef SQLITE_DEBUG_SORTER_THREADS
+static void vdbeSorterWorkDebug(SortSubtask *pTask, const char *zEvent){
+  i64 t;
+  int iTask = (pTask - pTask->pSorter->aTask);
+  sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t);
+  fprintf(stderr, "%lld:%d %s\n", t, iTask, zEvent);
+}
+static void vdbeSorterRewindDebug(const char *zEvent){
+  i64 t = 0;
+  sqlite3_vfs *pVfs = sqlite3_vfs_find(0);
+  if( ALWAYS(pVfs) ) sqlite3OsCurrentTimeInt64(pVfs, &t);
+  fprintf(stderr, "%lld:X %s\n", t, zEvent);
+}
+static void vdbeSorterPopulateDebug(
+  SortSubtask *pTask,
+  const char *zEvent
+){
+  i64 t;
+  int iTask = (pTask - pTask->pSorter->aTask);
+  sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t);
+  fprintf(stderr, "%lld:bg%d %s\n", t, iTask, zEvent);
+}
+static void vdbeSorterBlockDebug(
+  SortSubtask *pTask,
+  int bBlocked,
+  const char *zEvent
+){
+  if( bBlocked ){
+    i64 t;
+    sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t);
+    fprintf(stderr, "%lld:main %s\n", t, zEvent);
+  }
+}
+#else
+# define vdbeSorterWorkDebug(x,y)
+# define vdbeSorterRewindDebug(y)
+# define vdbeSorterPopulateDebug(x,y)
+# define vdbeSorterBlockDebug(x,y,z)
+#endif
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** Join thread pTask->thread.
+*/
+static int vdbeSorterJoinThread(SortSubtask *pTask){
+  int rc = SQLITE_OK;
+  if( pTask->pThread ){
+#ifdef SQLITE_DEBUG_SORTER_THREADS
+    int bDone = pTask->bDone;
+#endif
+    void *pRet = SQLITE_INT_TO_PTR(SQLITE_ERROR);
+    vdbeSorterBlockDebug(pTask, !bDone, "enter");
+    (void)sqlite3ThreadJoin(pTask->pThread, &pRet);
+    vdbeSorterBlockDebug(pTask, !bDone, "exit");
+    rc = SQLITE_PTR_TO_INT(pRet);
+    assert( pTask->bDone==1 );
+    pTask->bDone = 0;
+    pTask->pThread = 0;
+  }
+  return rc;
+}
+
+/*
+** Launch a background thread to run xTask(pIn).
+*/
+static int vdbeSorterCreateThread(
+  SortSubtask *pTask,             /* Thread will use this task object */
+  void *(*xTask)(void*),          /* Routine to run in a separate thread */
+  void *pIn                       /* Argument passed into xTask() */
+){
+  assert( pTask->pThread==0 && pTask->bDone==0 );
+  return sqlite3ThreadCreate(&pTask->pThread, xTask, pIn);
+}
+
+/*
+** Join all outstanding threads launched by SorterWrite() to create
+** level-0 PMAs.
+*/
+static int vdbeSorterJoinAll(VdbeSorter *pSorter, int rcin){
+  int rc = rcin;
+  int i;
+
+  /* This function is always called by the main user thread.
+  **
+  ** If this function is being called after SorterRewind() has been called,
+  ** it is possible that thread pSorter->aTask[pSorter->nTask-1].pThread
+  ** is currently attempt to join one of the other threads. To avoid a race
+  ** condition where this thread also attempts to join the same object, join
+  ** thread pSorter->aTask[pSorter->nTask-1].pThread first. */
+  for(i=pSorter->nTask-1; i>=0; i--){
+    SortSubtask *pTask = &pSorter->aTask[i];
+    int rc2 = vdbeSorterJoinThread(pTask);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+  return rc;
+}
+#else
+# define vdbeSorterJoinAll(x,rcin) (rcin)
+# define vdbeSorterJoinThread(pTask) SQLITE_OK
+#endif
+
+/*
+** Allocate a new MergeEngine object capable of handling up to
+** nReader PmaReader inputs.
+**
+** nReader is automatically rounded up to the next power of two.
+** nReader may not exceed SORTER_MAX_MERGE_COUNT even after rounding up.
+*/
+static MergeEngine *vdbeMergeEngineNew(int nReader){
+  int N = 2;                      /* Smallest power of two >= nReader */
+  int nByte;                      /* Total bytes of space to allocate */
+  MergeEngine *pNew;              /* Pointer to allocated object to return */
+
+  assert( nReader<=SORTER_MAX_MERGE_COUNT );
+
+  while( N<nReader ) N += N;
+  nByte = sizeof(MergeEngine) + N * (sizeof(int) + sizeof(PmaReader));
+
+  pNew = sqlite3FaultSim(100) ? 0 : (MergeEngine*)sqlite3MallocZero(nByte);
+  if( pNew ){
+    pNew->nTree = N;
+    pNew->pTask = 0;
+    pNew->aReadr = (PmaReader*)&pNew[1];
+    pNew->aTree = (int*)&pNew->aReadr[N];
+  }
+  return pNew;
+}
+
+/*
+** Free the MergeEngine object passed as the only argument.
+*/
+static void vdbeMergeEngineFree(MergeEngine *pMerger){
+  int i;
+  if( pMerger ){
+    for(i=0; i<pMerger->nTree; i++){
+      vdbePmaReaderClear(&pMerger->aReadr[i]);
+    }
+  }
+  sqlite3_free(pMerger);
+}
+
+/*
+** Free all resources associated with the IncrMerger object indicated by
+** the first argument.
+*/
+static void vdbeIncrFree(IncrMerger *pIncr){
+  if( pIncr ){
+#if SQLITE_MAX_WORKER_THREADS>0
+    if( pIncr->bUseThread ){
+      vdbeSorterJoinThread(pIncr->pTask);
+      if( pIncr->aFile[0].pFd ) sqlite3OsCloseFree(pIncr->aFile[0].pFd);
+      if( pIncr->aFile[1].pFd ) sqlite3OsCloseFree(pIncr->aFile[1].pFd);
+    }
+#endif
+    vdbeMergeEngineFree(pIncr->pMerger);
+    sqlite3_free(pIncr);
+  }
+}
+
+/*
+** Reset a sorting cursor back to its original empty state.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSorterReset(sqlite3 *db, VdbeSorter *pSorter){
+  int i;
+  (void)vdbeSorterJoinAll(pSorter, SQLITE_OK);
+  assert( pSorter->bUseThreads || pSorter->pReader==0 );
+#if SQLITE_MAX_WORKER_THREADS>0
+  if( pSorter->pReader ){
+    vdbePmaReaderClear(pSorter->pReader);
+    sqlite3DbFree(db, pSorter->pReader);
+    pSorter->pReader = 0;
+  }
+#endif
+  vdbeMergeEngineFree(pSorter->pMerger);
+  pSorter->pMerger = 0;
+  for(i=0; i<pSorter->nTask; i++){
+    SortSubtask *pTask = &pSorter->aTask[i];
+    vdbeSortSubtaskCleanup(db, pTask);
+    pTask->pSorter = pSorter;
+  }
+  if( pSorter->list.aMemory==0 ){
+    vdbeSorterRecordFree(0, pSorter->list.pList);
+  }
+  pSorter->list.pList = 0;
+  pSorter->list.szPMA = 0;
+  pSorter->bUsePMA = 0;
+  pSorter->iMemory = 0;
+  pSorter->mxKeysize = 0;
+  sqlite3DbFree(db, pSorter->pUnpacked);
+  pSorter->pUnpacked = 0;
+}
+
+/*
+** Free any cursor components allocated by sqlite3VdbeSorterXXX routines.
+*/
+SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *db, VdbeCursor *pCsr){
+  VdbeSorter *pSorter;
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  if( pSorter ){
+    sqlite3VdbeSorterReset(db, pSorter);
+    sqlite3_free(pSorter->list.aMemory);
+    sqlite3DbFree(db, pSorter);
+    pCsr->uc.pSorter = 0;
+  }
+}
+
+#if SQLITE_MAX_MMAP_SIZE>0
+/*
+** The first argument is a file-handle open on a temporary file. The file
+** is guaranteed to be nByte bytes or smaller in size. This function
+** attempts to extend the file to nByte bytes in size and to ensure that
+** the VFS has memory mapped it.
+**
+** Whether or not the file does end up memory mapped of course depends on
+** the specific VFS implementation.
+*/
+static void vdbeSorterExtendFile(sqlite3 *db, sqlite3_file *pFd, i64 nByte){
+  if( nByte<=(i64)(db->nMaxSorterMmap) && pFd->pMethods->iVersion>=3 ){
+    void *p = 0;
+    int chunksize = 4*1024;
+    sqlite3OsFileControlHint(pFd, SQLITE_FCNTL_CHUNK_SIZE, &chunksize);
+    sqlite3OsFileControlHint(pFd, SQLITE_FCNTL_SIZE_HINT, &nByte);
+    sqlite3OsFetch(pFd, 0, (int)nByte, &p);
+    if( p ) sqlite3OsUnfetch(pFd, 0, p);
+  }
+}
+#else
+# define vdbeSorterExtendFile(x,y,z)
+#endif
+
+/*
+** Allocate space for a file-handle and open a temporary file. If successful,
+** set *ppFd to point to the malloc'd file-handle and return SQLITE_OK.
+** Otherwise, set *ppFd to 0 and return an SQLite error code.
+*/
+static int vdbeSorterOpenTempFile(
+  sqlite3 *db,                    /* Database handle doing sort */
+  i64 nExtend,                    /* Attempt to extend file to this size */
+  sqlite3_file **ppFd
+){
+  int rc;
+  if( sqlite3FaultSim(202) ) return SQLITE_IOERR_ACCESS;
+  rc = sqlite3OsOpenMalloc(db->pVfs, 0, ppFd,
+      SQLITE_OPEN_TEMP_JOURNAL |
+      SQLITE_OPEN_READWRITE    | SQLITE_OPEN_CREATE |
+      SQLITE_OPEN_EXCLUSIVE    | SQLITE_OPEN_DELETEONCLOSE, &rc
+  );
+  if( rc==SQLITE_OK ){
+    i64 max = SQLITE_MAX_MMAP_SIZE;
+    sqlite3OsFileControlHint(*ppFd, SQLITE_FCNTL_MMAP_SIZE, (void*)&max);
+    if( nExtend>0 ){
+      vdbeSorterExtendFile(db, *ppFd, nExtend);
+    }
+  }
+  return rc;
+}
+
+/*
+** If it has not already been allocated, allocate the UnpackedRecord
+** structure at pTask->pUnpacked. Return SQLITE_OK if successful (or
+** if no allocation was required), or SQLITE_NOMEM otherwise.
+*/
+static int vdbeSortAllocUnpacked(SortSubtask *pTask){
+  if( pTask->pUnpacked==0 ){
+    pTask->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pTask->pSorter->pKeyInfo);
+    if( pTask->pUnpacked==0 ) return SQLITE_NOMEM_BKPT;
+    pTask->pUnpacked->nField = pTask->pSorter->pKeyInfo->nKeyField;
+    pTask->pUnpacked->errCode = 0;
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** Merge the two sorted lists p1 and p2 into a single list.
+*/
+static SorterRecord *vdbeSorterMerge(
+  SortSubtask *pTask,             /* Calling thread context */
+  SorterRecord *p1,               /* First list to merge */
+  SorterRecord *p2                /* Second list to merge */
+){
+  SorterRecord *pFinal = 0;
+  SorterRecord **pp = &pFinal;
+  int bCached = 0;
+
+  assert( p1!=0 && p2!=0 );
+  for(;;){
+    int res;
+    res = pTask->xCompare(
+        pTask, &bCached, SRVAL(p1), p1->nVal, SRVAL(p2), p2->nVal
+    );
+
+    if( res<=0 ){
+      *pp = p1;
+      pp = &p1->u.pNext;
+      p1 = p1->u.pNext;
+      if( p1==0 ){
+        *pp = p2;
+        break;
+      }
+    }else{
+      *pp = p2;
+      pp = &p2->u.pNext;
+      p2 = p2->u.pNext;
+      bCached = 0;
+      if( p2==0 ){
+        *pp = p1;
+        break;
+      }
+    }
+  }
+  return pFinal;
+}
+
+/*
+** Return the SorterCompare function to compare values collected by the
+** sorter object passed as the only argument.
+*/
+static SorterCompare vdbeSorterGetCompare(VdbeSorter *p){
+  if( p->typeMask==SORTER_TYPE_INTEGER ){
+    return vdbeSorterCompareInt;
+  }else if( p->typeMask==SORTER_TYPE_TEXT ){
+    return vdbeSorterCompareText;
+  }
+  return vdbeSorterCompare;
+}
+
+/*
+** Sort the linked list of records headed at pTask->pList. Return
+** SQLITE_OK if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if
+** an error occurs.
+*/
+static int vdbeSorterSort(SortSubtask *pTask, SorterList *pList){
+  int i;
+  SorterRecord *p;
+  int rc;
+  SorterRecord *aSlot[64];
+
+  rc = vdbeSortAllocUnpacked(pTask);
+  if( rc!=SQLITE_OK ) return rc;
+
+  p = pList->pList;
+  pTask->xCompare = vdbeSorterGetCompare(pTask->pSorter);
+  memset(aSlot, 0, sizeof(aSlot));
+
+  while( p ){
+    SorterRecord *pNext;
+    if( pList->aMemory ){
+      if( (u8*)p==pList->aMemory ){
+        pNext = 0;
+      }else{
+        assert( p->u.iNext<sqlite3MallocSize(pList->aMemory) );
+        pNext = (SorterRecord*)&pList->aMemory[p->u.iNext];
+      }
+    }else{
+      pNext = p->u.pNext;
+    }
+
+    p->u.pNext = 0;
+    for(i=0; aSlot[i]; i++){
+      p = vdbeSorterMerge(pTask, p, aSlot[i]);
+      aSlot[i] = 0;
+    }
+    aSlot[i] = p;
+    p = pNext;
+  }
+
+  p = 0;
+  for(i=0; i<ArraySize(aSlot); i++){
+    if( aSlot[i]==0 ) continue;
+    p = p ? vdbeSorterMerge(pTask, p, aSlot[i]) : aSlot[i];
+  }
+  pList->pList = p;
+
+  assert( pTask->pUnpacked->errCode==SQLITE_OK
+       || pTask->pUnpacked->errCode==SQLITE_NOMEM
+  );
+  return pTask->pUnpacked->errCode;
+}
+
+/*
+** Initialize a PMA-writer object.
+*/
+static void vdbePmaWriterInit(
+  sqlite3_file *pFd,              /* File handle to write to */
+  PmaWriter *p,                   /* Object to populate */
+  int nBuf,                       /* Buffer size */
+  i64 iStart                      /* Offset of pFd to begin writing at */
+){
+  memset(p, 0, sizeof(PmaWriter));
+  p->aBuffer = (u8*)sqlite3Malloc(nBuf);
+  if( !p->aBuffer ){
+    p->eFWErr = SQLITE_NOMEM_BKPT;
+  }else{
+    p->iBufEnd = p->iBufStart = (iStart % nBuf);
+    p->iWriteOff = iStart - p->iBufStart;
+    p->nBuffer = nBuf;
+    p->pFd = pFd;
+  }
+}
+
+/*
+** Write nData bytes of data to the PMA. Return SQLITE_OK
+** if successful, or an SQLite error code if an error occurs.
+*/
+static void vdbePmaWriteBlob(PmaWriter *p, u8 *pData, int nData){
+  int nRem = nData;
+  while( nRem>0 && p->eFWErr==0 ){
+    int nCopy = nRem;
+    if( nCopy>(p->nBuffer - p->iBufEnd) ){
+      nCopy = p->nBuffer - p->iBufEnd;
+    }
+
+    memcpy(&p->aBuffer[p->iBufEnd], &pData[nData-nRem], nCopy);
+    p->iBufEnd += nCopy;
+    if( p->iBufEnd==p->nBuffer ){
+      p->eFWErr = sqlite3OsWrite(p->pFd,
+          &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart,
+          p->iWriteOff + p->iBufStart
+      );
+      p->iBufStart = p->iBufEnd = 0;
+      p->iWriteOff += p->nBuffer;
+    }
+    assert( p->iBufEnd<p->nBuffer );
+
+    nRem -= nCopy;
+  }
+}
+
+/*
+** Flush any buffered data to disk and clean up the PMA-writer object.
+** The results of using the PMA-writer after this call are undefined.
+** Return SQLITE_OK if flushing the buffered data succeeds or is not
+** required. Otherwise, return an SQLite error code.
+**
+** Before returning, set *piEof to the offset immediately following the
+** last byte written to the file.
+*/
+static int vdbePmaWriterFinish(PmaWriter *p, i64 *piEof){
+  int rc;
+  if( p->eFWErr==0 && ALWAYS(p->aBuffer) && p->iBufEnd>p->iBufStart ){
+    p->eFWErr = sqlite3OsWrite(p->pFd,
+        &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart,
+        p->iWriteOff + p->iBufStart
+    );
+  }
+  *piEof = (p->iWriteOff + p->iBufEnd);
+  sqlite3_free(p->aBuffer);
+  rc = p->eFWErr;
+  memset(p, 0, sizeof(PmaWriter));
+  return rc;
+}
+
+/*
+** Write value iVal encoded as a varint to the PMA. Return
+** SQLITE_OK if successful, or an SQLite error code if an error occurs.
+*/
+static void vdbePmaWriteVarint(PmaWriter *p, u64 iVal){
+  int nByte;
+  u8 aByte[10];
+  nByte = sqlite3PutVarint(aByte, iVal);
+  vdbePmaWriteBlob(p, aByte, nByte);
+}
+
+/*
+** Write the current contents of in-memory linked-list pList to a level-0
+** PMA in the temp file belonging to sub-task pTask. Return SQLITE_OK if
+** successful, or an SQLite error code otherwise.
+**
+** The format of a PMA is:
+**
+**     * A varint. This varint contains the total number of bytes of content
+**       in the PMA (not including the varint itself).
+**
+**     * One or more records packed end-to-end in order of ascending keys.
+**       Each record consists of a varint followed by a blob of data (the
+**       key). The varint is the number of bytes in the blob of data.
+*/
+static int vdbeSorterListToPMA(SortSubtask *pTask, SorterList *pList){
+  sqlite3 *db = pTask->pSorter->db;
+  int rc = SQLITE_OK;             /* Return code */
+  PmaWriter writer;               /* Object used to write to the file */
+
+#ifdef SQLITE_DEBUG
+  /* Set iSz to the expected size of file pTask->file after writing the PMA.
+  ** This is used by an assert() statement at the end of this function.  */
+  i64 iSz = pList->szPMA + sqlite3VarintLen(pList->szPMA) + pTask->file.iEof;
+#endif
+
+  vdbeSorterWorkDebug(pTask, "enter");
+  memset(&writer, 0, sizeof(PmaWriter));
+  assert( pList->szPMA>0 );
+
+  /* If the first temporary PMA file has not been opened, open it now. */
+  if( pTask->file.pFd==0 ){
+    rc = vdbeSorterOpenTempFile(db, 0, &pTask->file.pFd);
+    assert( rc!=SQLITE_OK || pTask->file.pFd );
+    assert( pTask->file.iEof==0 );
+    assert( pTask->nPMA==0 );
+  }
+
+  /* Try to get the file to memory map */
+  if( rc==SQLITE_OK ){
+    vdbeSorterExtendFile(db, pTask->file.pFd, pTask->file.iEof+pList->szPMA+9);
+  }
+
+  /* Sort the list */
+  if( rc==SQLITE_OK ){
+    rc = vdbeSorterSort(pTask, pList);
+  }
+
+  if( rc==SQLITE_OK ){
+    SorterRecord *p;
+    SorterRecord *pNext = 0;
+
+    vdbePmaWriterInit(pTask->file.pFd, &writer, pTask->pSorter->pgsz,
+                      pTask->file.iEof);
+    pTask->nPMA++;
+    vdbePmaWriteVarint(&writer, pList->szPMA);
+    for(p=pList->pList; p; p=pNext){
+      pNext = p->u.pNext;
+      vdbePmaWriteVarint(&writer, p->nVal);
+      vdbePmaWriteBlob(&writer, SRVAL(p), p->nVal);
+      if( pList->aMemory==0 ) sqlite3_free(p);
+    }
+    pList->pList = p;
+    rc = vdbePmaWriterFinish(&writer, &pTask->file.iEof);
+  }
+
+  vdbeSorterWorkDebug(pTask, "exit");
+  assert( rc!=SQLITE_OK || pList->pList==0 );
+  assert( rc!=SQLITE_OK || pTask->file.iEof==iSz );
+  return rc;
+}
+
+/*
+** Advance the MergeEngine to its next entry.
+** Set *pbEof to true there is no next entry because
+** the MergeEngine has reached the end of all its inputs.
+**
+** Return SQLITE_OK if successful or an error code if an error occurs.
+*/
+static int vdbeMergeEngineStep(
+  MergeEngine *pMerger,      /* The merge engine to advance to the next row */
+  int *pbEof                 /* Set TRUE at EOF.  Set false for more content */
+){
+  int rc;
+  int iPrev = pMerger->aTree[1];/* Index of PmaReader to advance */
+  SortSubtask *pTask = pMerger->pTask;
+
+  /* Advance the current PmaReader */
+  rc = vdbePmaReaderNext(&pMerger->aReadr[iPrev]);
+
+  /* Update contents of aTree[] */
+  if( rc==SQLITE_OK ){
+    int i;                      /* Index of aTree[] to recalculate */
+    PmaReader *pReadr1;         /* First PmaReader to compare */
+    PmaReader *pReadr2;         /* Second PmaReader to compare */
+    int bCached = 0;
+
+    /* Find the first two PmaReaders to compare. The one that was just
+    ** advanced (iPrev) and the one next to it in the array.  */
+    pReadr1 = &pMerger->aReadr[(iPrev & 0xFFFE)];
+    pReadr2 = &pMerger->aReadr[(iPrev | 0x0001)];
+
+    for(i=(pMerger->nTree+iPrev)/2; i>0; i=i/2){
+      /* Compare pReadr1 and pReadr2. Store the result in variable iRes. */
+      int iRes;
+      if( pReadr1->pFd==0 ){
+        iRes = +1;
+      }else if( pReadr2->pFd==0 ){
+        iRes = -1;
+      }else{
+        iRes = pTask->xCompare(pTask, &bCached,
+            pReadr1->aKey, pReadr1->nKey, pReadr2->aKey, pReadr2->nKey
+        );
+      }
+
+      /* If pReadr1 contained the smaller value, set aTree[i] to its index.
+      ** Then set pReadr2 to the next PmaReader to compare to pReadr1. In this
+      ** case there is no cache of pReadr2 in pTask->pUnpacked, so set
+      ** pKey2 to point to the record belonging to pReadr2.
+      **
+      ** Alternatively, if pReadr2 contains the smaller of the two values,
+      ** set aTree[i] to its index and update pReadr1. If vdbeSorterCompare()
+      ** was actually called above, then pTask->pUnpacked now contains
+      ** a value equivalent to pReadr2. So set pKey2 to NULL to prevent
+      ** vdbeSorterCompare() from decoding pReadr2 again.
+      **
+      ** If the two values were equal, then the value from the oldest
+      ** PMA should be considered smaller. The VdbeSorter.aReadr[] array
+      ** is sorted from oldest to newest, so pReadr1 contains older values
+      ** than pReadr2 iff (pReadr1<pReadr2).  */
+      if( iRes<0 || (iRes==0 && pReadr1<pReadr2) ){
+        pMerger->aTree[i] = (int)(pReadr1 - pMerger->aReadr);
+        pReadr2 = &pMerger->aReadr[ pMerger->aTree[i ^ 0x0001] ];
+        bCached = 0;
+      }else{
+        if( pReadr1->pFd ) bCached = 0;
+        pMerger->aTree[i] = (int)(pReadr2 - pMerger->aReadr);
+        pReadr1 = &pMerger->aReadr[ pMerger->aTree[i ^ 0x0001] ];
+      }
+    }
+    *pbEof = (pMerger->aReadr[pMerger->aTree[1]].pFd==0);
+  }
+
+  return (rc==SQLITE_OK ? pTask->pUnpacked->errCode : rc);
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** The main routine for background threads that write level-0 PMAs.
+*/
+static void *vdbeSorterFlushThread(void *pCtx){
+  SortSubtask *pTask = (SortSubtask*)pCtx;
+  int rc;                         /* Return code */
+  assert( pTask->bDone==0 );
+  rc = vdbeSorterListToPMA(pTask, &pTask->list);
+  pTask->bDone = 1;
+  return SQLITE_INT_TO_PTR(rc);
+}
+#endif /* SQLITE_MAX_WORKER_THREADS>0 */
+
+/*
+** Flush the current contents of VdbeSorter.list to a new PMA, possibly
+** using a background thread.
+*/
+static int vdbeSorterFlushPMA(VdbeSorter *pSorter){
+#if SQLITE_MAX_WORKER_THREADS==0
+  pSorter->bUsePMA = 1;
+  return vdbeSorterListToPMA(&pSorter->aTask[0], &pSorter->list);
+#else
+  int rc = SQLITE_OK;
+  int i;
+  SortSubtask *pTask = 0;    /* Thread context used to create new PMA */
+  int nWorker = (pSorter->nTask-1);
+
+  /* Set the flag to indicate that at least one PMA has been written.
+  ** Or will be, anyhow.  */
+  pSorter->bUsePMA = 1;
+
+  /* Select a sub-task to sort and flush the current list of in-memory
+  ** records to disk. If the sorter is running in multi-threaded mode,
+  ** round-robin between the first (pSorter->nTask-1) tasks. Except, if
+  ** the background thread from a sub-tasks previous turn is still running,
+  ** skip it. If the first (pSorter->nTask-1) sub-tasks are all still busy,
+  ** fall back to using the final sub-task. The first (pSorter->nTask-1)
+  ** sub-tasks are preferred as they use background threads - the final
+  ** sub-task uses the main thread. */
+  for(i=0; i<nWorker; i++){
+    int iTest = (pSorter->iPrev + i + 1) % nWorker;
+    pTask = &pSorter->aTask[iTest];
+    if( pTask->bDone ){
+      rc = vdbeSorterJoinThread(pTask);
+    }
+    if( rc!=SQLITE_OK || pTask->pThread==0 ) break;
+  }
+
+  if( rc==SQLITE_OK ){
+    if( i==nWorker ){
+      /* Use the foreground thread for this operation */
+      rc = vdbeSorterListToPMA(&pSorter->aTask[nWorker], &pSorter->list);
+    }else{
+      /* Launch a background thread for this operation */
+      u8 *aMem;
+      void *pCtx;
+
+      assert( pTask!=0 );
+      assert( pTask->pThread==0 && pTask->bDone==0 );
+      assert( pTask->list.pList==0 );
+      assert( pTask->list.aMemory==0 || pSorter->list.aMemory!=0 );
+
+      aMem = pTask->list.aMemory;
+      pCtx = (void*)pTask;
+      pSorter->iPrev = (u8)(pTask - pSorter->aTask);
+      pTask->list = pSorter->list;
+      pSorter->list.pList = 0;
+      pSorter->list.szPMA = 0;
+      if( aMem ){
+        pSorter->list.aMemory = aMem;
+        pSorter->nMemory = sqlite3MallocSize(aMem);
+      }else if( pSorter->list.aMemory ){
+        pSorter->list.aMemory = sqlite3Malloc(pSorter->nMemory);
+        if( !pSorter->list.aMemory ) return SQLITE_NOMEM_BKPT;
+      }
+
+      rc = vdbeSorterCreateThread(pTask, vdbeSorterFlushThread, pCtx);
+    }
+  }
+
+  return rc;
+#endif /* SQLITE_MAX_WORKER_THREADS!=0 */
+}
+
+/*
+** Add a record to the sorter.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterWrite(
+  const VdbeCursor *pCsr,         /* Sorter cursor */
+  Mem *pVal                       /* Memory cell containing record */
+){
+  VdbeSorter *pSorter;
+  int rc = SQLITE_OK;             /* Return Code */
+  SorterRecord *pNew;             /* New list element */
+  int bFlush;                     /* True to flush contents of memory to PMA */
+  i64 nReq;                       /* Bytes of memory required */
+  i64 nPMA;                       /* Bytes of PMA space required */
+  int t;                          /* serial type of first record field */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  getVarint32NR((const u8*)&pVal->z[1], t);
+  if( t>0 && t<10 && t!=7 ){
+    pSorter->typeMask &= SORTER_TYPE_INTEGER;
+  }else if( t>10 && (t & 0x01) ){
+    pSorter->typeMask &= SORTER_TYPE_TEXT;
+  }else{
+    pSorter->typeMask = 0;
+  }
+
+  assert( pSorter );
+
+  /* Figure out whether or not the current contents of memory should be
+  ** flushed to a PMA before continuing. If so, do so.
+  **
+  ** If using the single large allocation mode (pSorter->aMemory!=0), then
+  ** flush the contents of memory to a new PMA if (a) at least one value is
+  ** already in memory and (b) the new value will not fit in memory.
+  **
+  ** Or, if using separate allocations for each record, flush the contents
+  ** of memory to a PMA if either of the following are true:
+  **
+  **   * The total memory allocated for the in-memory list is greater
+  **     than (page-size * cache-size), or
+  **
+  **   * The total memory allocated for the in-memory list is greater
+  **     than (page-size * 10) and sqlite3HeapNearlyFull() returns true.
+  */
+  nReq = pVal->n + sizeof(SorterRecord);
+  nPMA = pVal->n + sqlite3VarintLen(pVal->n);
+  if( pSorter->mxPmaSize ){
+    if( pSorter->list.aMemory ){
+      bFlush = pSorter->iMemory && (pSorter->iMemory+nReq) > pSorter->mxPmaSize;
+    }else{
+      bFlush = (
+          (pSorter->list.szPMA > pSorter->mxPmaSize)
+       || (pSorter->list.szPMA > pSorter->mnPmaSize && sqlite3HeapNearlyFull())
+      );
+    }
+    if( bFlush ){
+      rc = vdbeSorterFlushPMA(pSorter);
+      pSorter->list.szPMA = 0;
+      pSorter->iMemory = 0;
+      assert( rc!=SQLITE_OK || pSorter->list.pList==0 );
+    }
+  }
+
+  pSorter->list.szPMA += nPMA;
+  if( nPMA>pSorter->mxKeysize ){
+    pSorter->mxKeysize = nPMA;
+  }
+
+  if( pSorter->list.aMemory ){
+    int nMin = pSorter->iMemory + nReq;
+
+    if( nMin>pSorter->nMemory ){
+      u8 *aNew;
+      sqlite3_int64 nNew = 2 * (sqlite3_int64)pSorter->nMemory;
+      int iListOff = -1;
+      if( pSorter->list.pList ){
+        iListOff = (u8*)pSorter->list.pList - pSorter->list.aMemory;
+      }
+      while( nNew < nMin ) nNew = nNew*2;
+      if( nNew > pSorter->mxPmaSize ) nNew = pSorter->mxPmaSize;
+      if( nNew < nMin ) nNew = nMin;
+      aNew = sqlite3Realloc(pSorter->list.aMemory, nNew);
+      if( !aNew ) return SQLITE_NOMEM_BKPT;
+      if( iListOff>=0 ){
+        pSorter->list.pList = (SorterRecord*)&aNew[iListOff];
+      }
+      pSorter->list.aMemory = aNew;
+      pSorter->nMemory = nNew;
+    }
+
+    pNew = (SorterRecord*)&pSorter->list.aMemory[pSorter->iMemory];
+    pSorter->iMemory += ROUND8(nReq);
+    if( pSorter->list.pList ){
+      pNew->u.iNext = (int)((u8*)(pSorter->list.pList) - pSorter->list.aMemory);
+    }
+  }else{
+    pNew = (SorterRecord *)sqlite3Malloc(nReq);
+    if( pNew==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    pNew->u.pNext = pSorter->list.pList;
+  }
+
+  memcpy(SRVAL(pNew), pVal->z, pVal->n);
+  pNew->nVal = pVal->n;
+  pSorter->list.pList = pNew;
+
+  return rc;
+}
+
+/*
+** Read keys from pIncr->pMerger and populate pIncr->aFile[1]. The format
+** of the data stored in aFile[1] is the same as that used by regular PMAs,
+** except that the number-of-bytes varint is omitted from the start.
+*/
+static int vdbeIncrPopulate(IncrMerger *pIncr){
+  int rc = SQLITE_OK;
+  int rc2;
+  i64 iStart = pIncr->iStartOff;
+  SorterFile *pOut = &pIncr->aFile[1];
+  SortSubtask *pTask = pIncr->pTask;
+  MergeEngine *pMerger = pIncr->pMerger;
+  PmaWriter writer;
+  assert( pIncr->bEof==0 );
+
+  vdbeSorterPopulateDebug(pTask, "enter");
+
+  vdbePmaWriterInit(pOut->pFd, &writer, pTask->pSorter->pgsz, iStart);
+  while( rc==SQLITE_OK ){
+    int dummy;
+    PmaReader *pReader = &pMerger->aReadr[ pMerger->aTree[1] ];
+    int nKey = pReader->nKey;
+    i64 iEof = writer.iWriteOff + writer.iBufEnd;
+
+    /* Check if the output file is full or if the input has been exhausted.
+    ** In either case exit the loop. */
+    if( pReader->pFd==0 ) break;
+    if( (iEof + nKey + sqlite3VarintLen(nKey))>(iStart + pIncr->mxSz) ) break;
+
+    /* Write the next key to the output. */
+    vdbePmaWriteVarint(&writer, nKey);
+    vdbePmaWriteBlob(&writer, pReader->aKey, nKey);
+    assert( pIncr->pMerger->pTask==pTask );
+    rc = vdbeMergeEngineStep(pIncr->pMerger, &dummy);
+  }
+
+  rc2 = vdbePmaWriterFinish(&writer, &pOut->iEof);
+  if( rc==SQLITE_OK ) rc = rc2;
+  vdbeSorterPopulateDebug(pTask, "exit");
+  return rc;
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** The main routine for background threads that populate aFile[1] of
+** multi-threaded IncrMerger objects.
+*/
+static void *vdbeIncrPopulateThread(void *pCtx){
+  IncrMerger *pIncr = (IncrMerger*)pCtx;
+  void *pRet = SQLITE_INT_TO_PTR( vdbeIncrPopulate(pIncr) );
+  pIncr->pTask->bDone = 1;
+  return pRet;
+}
+
+/*
+** Launch a background thread to populate aFile[1] of pIncr.
+*/
+static int vdbeIncrBgPopulate(IncrMerger *pIncr){
+  void *p = (void*)pIncr;
+  assert( pIncr->bUseThread );
+  return vdbeSorterCreateThread(pIncr->pTask, vdbeIncrPopulateThread, p);
+}
+#endif
+
+/*
+** This function is called when the PmaReader corresponding to pIncr has
+** finished reading the contents of aFile[0]. Its purpose is to "refill"
+** aFile[0] such that the PmaReader should start rereading it from the
+** beginning.
+**
+** For single-threaded objects, this is accomplished by literally reading
+** keys from pIncr->pMerger and repopulating aFile[0].
+**
+** For multi-threaded objects, all that is required is to wait until the
+** background thread is finished (if it is not already) and then swap
+** aFile[0] and aFile[1] in place. If the contents of pMerger have not
+** been exhausted, this function also launches a new background thread
+** to populate the new aFile[1].
+**
+** SQLITE_OK is returned on success, or an SQLite error code otherwise.
+*/
+static int vdbeIncrSwap(IncrMerger *pIncr){
+  int rc = SQLITE_OK;
+
+#if SQLITE_MAX_WORKER_THREADS>0
+  if( pIncr->bUseThread ){
+    rc = vdbeSorterJoinThread(pIncr->pTask);
+
+    if( rc==SQLITE_OK ){
+      SorterFile f0 = pIncr->aFile[0];
+      pIncr->aFile[0] = pIncr->aFile[1];
+      pIncr->aFile[1] = f0;
+    }
+
+    if( rc==SQLITE_OK ){
+      if( pIncr->aFile[0].iEof==pIncr->iStartOff ){
+        pIncr->bEof = 1;
+      }else{
+        rc = vdbeIncrBgPopulate(pIncr);
+      }
+    }
+  }else
+#endif
+  {
+    rc = vdbeIncrPopulate(pIncr);
+    pIncr->aFile[0] = pIncr->aFile[1];
+    if( pIncr->aFile[0].iEof==pIncr->iStartOff ){
+      pIncr->bEof = 1;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Allocate and return a new IncrMerger object to read data from pMerger.
+**
+** If an OOM condition is encountered, return NULL. In this case free the
+** pMerger argument before returning.
+*/
+static int vdbeIncrMergerNew(
+  SortSubtask *pTask,     /* The thread that will be using the new IncrMerger */
+  MergeEngine *pMerger,   /* The MergeEngine that the IncrMerger will control */
+  IncrMerger **ppOut      /* Write the new IncrMerger here */
+){
+  int rc = SQLITE_OK;
+  IncrMerger *pIncr = *ppOut = (IncrMerger*)
+       (sqlite3FaultSim(100) ? 0 : sqlite3MallocZero(sizeof(*pIncr)));
+  if( pIncr ){
+    pIncr->pMerger = pMerger;
+    pIncr->pTask = pTask;
+    pIncr->mxSz = MAX(pTask->pSorter->mxKeysize+9,pTask->pSorter->mxPmaSize/2);
+    pTask->file2.iEof += pIncr->mxSz;
+  }else{
+    vdbeMergeEngineFree(pMerger);
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  assert( *ppOut!=0 || rc!=SQLITE_OK );
+  return rc;
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** Set the "use-threads" flag on object pIncr.
+*/
+static void vdbeIncrMergerSetThreads(IncrMerger *pIncr){
+  pIncr->bUseThread = 1;
+  pIncr->pTask->file2.iEof -= pIncr->mxSz;
+}
+#endif /* SQLITE_MAX_WORKER_THREADS>0 */
+
+
+
+/*
+** Recompute pMerger->aTree[iOut] by comparing the next keys on the
+** two PmaReaders that feed that entry.  Neither of the PmaReaders
+** are advanced.  This routine merely does the comparison.
+*/
+static void vdbeMergeEngineCompare(
+  MergeEngine *pMerger,  /* Merge engine containing PmaReaders to compare */
+  int iOut               /* Store the result in pMerger->aTree[iOut] */
+){
+  int i1;
+  int i2;
+  int iRes;
+  PmaReader *p1;
+  PmaReader *p2;
+
+  assert( iOut<pMerger->nTree && iOut>0 );
+
+  if( iOut>=(pMerger->nTree/2) ){
+    i1 = (iOut - pMerger->nTree/2) * 2;
+    i2 = i1 + 1;
+  }else{
+    i1 = pMerger->aTree[iOut*2];
+    i2 = pMerger->aTree[iOut*2+1];
+  }
+
+  p1 = &pMerger->aReadr[i1];
+  p2 = &pMerger->aReadr[i2];
+
+  if( p1->pFd==0 ){
+    iRes = i2;
+  }else if( p2->pFd==0 ){
+    iRes = i1;
+  }else{
+    SortSubtask *pTask = pMerger->pTask;
+    int bCached = 0;
+    int res;
+    assert( pTask->pUnpacked!=0 );  /* from vdbeSortSubtaskMain() */
+    res = pTask->xCompare(
+        pTask, &bCached, p1->aKey, p1->nKey, p2->aKey, p2->nKey
+    );
+    if( res<=0 ){
+      iRes = i1;
+    }else{
+      iRes = i2;
+    }
+  }
+
+  pMerger->aTree[iOut] = iRes;
+}
+
+/*
+** Allowed values for the eMode parameter to vdbeMergeEngineInit()
+** and vdbePmaReaderIncrMergeInit().
+**
+** Only INCRINIT_NORMAL is valid in single-threaded builds (when
+** SQLITE_MAX_WORKER_THREADS==0).  The other values are only used
+** when there exists one or more separate worker threads.
+*/
+#define INCRINIT_NORMAL 0
+#define INCRINIT_TASK   1
+#define INCRINIT_ROOT   2
+
+/*
+** Forward reference required as the vdbeIncrMergeInit() and
+** vdbePmaReaderIncrInit() routines are called mutually recursively when
+** building a merge tree.
+*/
+static int vdbePmaReaderIncrInit(PmaReader *pReadr, int eMode);
+
+/*
+** Initialize the MergeEngine object passed as the second argument. Once this
+** function returns, the first key of merged data may be read from the
+** MergeEngine object in the usual fashion.
+**
+** If argument eMode is INCRINIT_ROOT, then it is assumed that any IncrMerge
+** objects attached to the PmaReader objects that the merger reads from have
+** already been populated, but that they have not yet populated aFile[0] and
+** set the PmaReader objects up to read from it. In this case all that is
+** required is to call vdbePmaReaderNext() on each PmaReader to point it at
+** its first key.
+**
+** Otherwise, if eMode is any value other than INCRINIT_ROOT, then use
+** vdbePmaReaderIncrMergeInit() to initialize each PmaReader that feeds data
+** to pMerger.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+static int vdbeMergeEngineInit(
+  SortSubtask *pTask,             /* Thread that will run pMerger */
+  MergeEngine *pMerger,           /* MergeEngine to initialize */
+  int eMode                       /* One of the INCRINIT_XXX constants */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* For looping over PmaReader objects */
+  int nTree;                      /* Number of subtrees to merge */
+
+  /* Failure to allocate the merge would have been detected prior to
+  ** invoking this routine */
+  assert( pMerger!=0 );
+
+  /* eMode is always INCRINIT_NORMAL in single-threaded mode */
+  assert( SQLITE_MAX_WORKER_THREADS>0 || eMode==INCRINIT_NORMAL );
+
+  /* Verify that the MergeEngine is assigned to a single thread */
+  assert( pMerger->pTask==0 );
+  pMerger->pTask = pTask;
+
+  nTree = pMerger->nTree;
+  for(i=0; i<nTree; i++){
+    if( SQLITE_MAX_WORKER_THREADS>0 && eMode==INCRINIT_ROOT ){
+      /* PmaReaders should be normally initialized in order, as if they are
+      ** reading from the same temp file this makes for more linear file IO.
+      ** However, in the INCRINIT_ROOT case, if PmaReader aReadr[nTask-1] is
+      ** in use it will block the vdbePmaReaderNext() call while it uses
+      ** the main thread to fill its buffer. So calling PmaReaderNext()
+      ** on this PmaReader before any of the multi-threaded PmaReaders takes
+      ** better advantage of multi-processor hardware. */
+      rc = vdbePmaReaderNext(&pMerger->aReadr[nTree-i-1]);
+    }else{
+      rc = vdbePmaReaderIncrInit(&pMerger->aReadr[i], INCRINIT_NORMAL);
+    }
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  for(i=pMerger->nTree-1; i>0; i--){
+    vdbeMergeEngineCompare(pMerger, i);
+  }
+  return pTask->pUnpacked->errCode;
+}
+
+/*
+** The PmaReader passed as the first argument is guaranteed to be an
+** incremental-reader (pReadr->pIncr!=0). This function serves to open
+** and/or initialize the temp file related fields of the IncrMerge
+** object at (pReadr->pIncr).
+**
+** If argument eMode is set to INCRINIT_NORMAL, then all PmaReaders
+** in the sub-tree headed by pReadr are also initialized. Data is then
+** loaded into the buffers belonging to pReadr and it is set to point to
+** the first key in its range.
+**
+** If argument eMode is set to INCRINIT_TASK, then pReadr is guaranteed
+** to be a multi-threaded PmaReader and this function is being called in a
+** background thread. In this case all PmaReaders in the sub-tree are
+** initialized as for INCRINIT_NORMAL and the aFile[1] buffer belonging to
+** pReadr is populated. However, pReadr itself is not set up to point
+** to its first key. A call to vdbePmaReaderNext() is still required to do
+** that.
+**
+** The reason this function does not call vdbePmaReaderNext() immediately
+** in the INCRINIT_TASK case is that vdbePmaReaderNext() assumes that it has
+** to block on thread (pTask->thread) before accessing aFile[1]. But, since
+** this entire function is being run by thread (pTask->thread), that will
+** lead to the current background thread attempting to join itself.
+**
+** Finally, if argument eMode is set to INCRINIT_ROOT, it may be assumed
+** that pReadr->pIncr is a multi-threaded IncrMerge objects, and that all
+** child-trees have already been initialized using IncrInit(INCRINIT_TASK).
+** In this case vdbePmaReaderNext() is called on all child PmaReaders and
+** the current PmaReader set to point to the first key in its range.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+static int vdbePmaReaderIncrMergeInit(PmaReader *pReadr, int eMode){
+  int rc = SQLITE_OK;
+  IncrMerger *pIncr = pReadr->pIncr;
+  SortSubtask *pTask = pIncr->pTask;
+  sqlite3 *db = pTask->pSorter->db;
+
+  /* eMode is always INCRINIT_NORMAL in single-threaded mode */
+  assert( SQLITE_MAX_WORKER_THREADS>0 || eMode==INCRINIT_NORMAL );
+
+  rc = vdbeMergeEngineInit(pTask, pIncr->pMerger, eMode);
+
+  /* Set up the required files for pIncr. A multi-threaded IncrMerge object
+  ** requires two temp files to itself, whereas a single-threaded object
+  ** only requires a region of pTask->file2. */
+  if( rc==SQLITE_OK ){
+    int mxSz = pIncr->mxSz;
+#if SQLITE_MAX_WORKER_THREADS>0
+    if( pIncr->bUseThread ){
+      rc = vdbeSorterOpenTempFile(db, mxSz, &pIncr->aFile[0].pFd);
+      if( rc==SQLITE_OK ){
+        rc = vdbeSorterOpenTempFile(db, mxSz, &pIncr->aFile[1].pFd);
+      }
+    }else
+#endif
+    /*if( !pIncr->bUseThread )*/{
+      if( pTask->file2.pFd==0 ){
+        assert( pTask->file2.iEof>0 );
+        rc = vdbeSorterOpenTempFile(db, pTask->file2.iEof, &pTask->file2.pFd);
+        pTask->file2.iEof = 0;
+      }
+      if( rc==SQLITE_OK ){
+        pIncr->aFile[1].pFd = pTask->file2.pFd;
+        pIncr->iStartOff = pTask->file2.iEof;
+        pTask->file2.iEof += mxSz;
+      }
+    }
+  }
+
+#if SQLITE_MAX_WORKER_THREADS>0
+  if( rc==SQLITE_OK && pIncr->bUseThread ){
+    /* Use the current thread to populate aFile[1], even though this
+    ** PmaReader is multi-threaded. If this is an INCRINIT_TASK object,
+    ** then this function is already running in background thread
+    ** pIncr->pTask->thread.
+    **
+    ** If this is the INCRINIT_ROOT object, then it is running in the
+    ** main VDBE thread. But that is Ok, as that thread cannot return
+    ** control to the VDBE or proceed with anything useful until the
+    ** first results are ready from this merger object anyway.
+    */
+    assert( eMode==INCRINIT_ROOT || eMode==INCRINIT_TASK );
+    rc = vdbeIncrPopulate(pIncr);
+  }
+#endif
+
+  if( rc==SQLITE_OK && (SQLITE_MAX_WORKER_THREADS==0 || eMode!=INCRINIT_TASK) ){
+    rc = vdbePmaReaderNext(pReadr);
+  }
+
+  return rc;
+}
+
+#if SQLITE_MAX_WORKER_THREADS>0
+/*
+** The main routine for vdbePmaReaderIncrMergeInit() operations run in
+** background threads.
+*/
+static void *vdbePmaReaderBgIncrInit(void *pCtx){
+  PmaReader *pReader = (PmaReader*)pCtx;
+  void *pRet = SQLITE_INT_TO_PTR(
+                  vdbePmaReaderIncrMergeInit(pReader,INCRINIT_TASK)
+               );
+  pReader->pIncr->pTask->bDone = 1;
+  return pRet;
+}
+#endif
+
+/*
+** If the PmaReader passed as the first argument is not an incremental-reader
+** (if pReadr->pIncr==0), then this function is a no-op. Otherwise, it invokes
+** the vdbePmaReaderIncrMergeInit() function with the parameters passed to
+** this routine to initialize the incremental merge.
+**
+** If the IncrMerger object is multi-threaded (IncrMerger.bUseThread==1),
+** then a background thread is launched to call vdbePmaReaderIncrMergeInit().
+** Or, if the IncrMerger is single threaded, the same function is called
+** using the current thread.
+*/
+static int vdbePmaReaderIncrInit(PmaReader *pReadr, int eMode){
+  IncrMerger *pIncr = pReadr->pIncr;   /* Incremental merger */
+  int rc = SQLITE_OK;                  /* Return code */
+  if( pIncr ){
+#if SQLITE_MAX_WORKER_THREADS>0
+    assert( pIncr->bUseThread==0 || eMode==INCRINIT_TASK );
+    if( pIncr->bUseThread ){
+      void *pCtx = (void*)pReadr;
+      rc = vdbeSorterCreateThread(pIncr->pTask, vdbePmaReaderBgIncrInit, pCtx);
+    }else
+#endif
+    {
+      rc = vdbePmaReaderIncrMergeInit(pReadr, eMode);
+    }
+  }
+  return rc;
+}
+
+/*
+** Allocate a new MergeEngine object to merge the contents of nPMA level-0
+** PMAs from pTask->file. If no error occurs, set *ppOut to point to
+** the new object and return SQLITE_OK. Or, if an error does occur, set *ppOut
+** to NULL and return an SQLite error code.
+**
+** When this function is called, *piOffset is set to the offset of the
+** first PMA to read from pTask->file. Assuming no error occurs, it is
+** set to the offset immediately following the last byte of the last
+** PMA before returning. If an error does occur, then the final value of
+** *piOffset is undefined.
+*/
+static int vdbeMergeEngineLevel0(
+  SortSubtask *pTask,             /* Sorter task to read from */
+  int nPMA,                       /* Number of PMAs to read */
+  i64 *piOffset,                  /* IN/OUT: Readr offset in pTask->file */
+  MergeEngine **ppOut             /* OUT: New merge-engine */
+){
+  MergeEngine *pNew;              /* Merge engine to return */
+  i64 iOff = *piOffset;
+  int i;
+  int rc = SQLITE_OK;
+
+  *ppOut = pNew = vdbeMergeEngineNew(nPMA);
+  if( pNew==0 ) rc = SQLITE_NOMEM_BKPT;
+
+  for(i=0; i<nPMA && rc==SQLITE_OK; i++){
+    i64 nDummy = 0;
+    PmaReader *pReadr = &pNew->aReadr[i];
+    rc = vdbePmaReaderInit(pTask, &pTask->file, iOff, pReadr, &nDummy);
+    iOff = pReadr->iEof;
+  }
+
+  if( rc!=SQLITE_OK ){
+    vdbeMergeEngineFree(pNew);
+    *ppOut = 0;
+  }
+  *piOffset = iOff;
+  return rc;
+}
+
+/*
+** Return the depth of a tree comprising nPMA PMAs, assuming a fanout of
+** SORTER_MAX_MERGE_COUNT. The returned value does not include leaf nodes.
+**
+** i.e.
+**
+**   nPMA<=16    -> TreeDepth() == 0
+**   nPMA<=256   -> TreeDepth() == 1
+**   nPMA<=65536 -> TreeDepth() == 2
+*/
+static int vdbeSorterTreeDepth(int nPMA){
+  int nDepth = 0;
+  i64 nDiv = SORTER_MAX_MERGE_COUNT;
+  while( nDiv < (i64)nPMA ){
+    nDiv = nDiv * SORTER_MAX_MERGE_COUNT;
+    nDepth++;
+  }
+  return nDepth;
+}
+
+/*
+** pRoot is the root of an incremental merge-tree with depth nDepth (according
+** to vdbeSorterTreeDepth()). pLeaf is the iSeq'th leaf to be added to the
+** tree, counting from zero. This function adds pLeaf to the tree.
+**
+** If successful, SQLITE_OK is returned. If an error occurs, an SQLite error
+** code is returned and pLeaf is freed.
+*/
+static int vdbeSorterAddToTree(
+  SortSubtask *pTask,             /* Task context */
+  int nDepth,                     /* Depth of tree according to TreeDepth() */
+  int iSeq,                       /* Sequence number of leaf within tree */
+  MergeEngine *pRoot,             /* Root of tree */
+  MergeEngine *pLeaf              /* Leaf to add to tree */
+){
+  int rc = SQLITE_OK;
+  int nDiv = 1;
+  int i;
+  MergeEngine *p = pRoot;
+  IncrMerger *pIncr;
+
+  rc = vdbeIncrMergerNew(pTask, pLeaf, &pIncr);
+
+  for(i=1; i<nDepth; i++){
+    nDiv = nDiv * SORTER_MAX_MERGE_COUNT;
+  }
+
+  for(i=1; i<nDepth && rc==SQLITE_OK; i++){
+    int iIter = (iSeq / nDiv) % SORTER_MAX_MERGE_COUNT;
+    PmaReader *pReadr = &p->aReadr[iIter];
+
+    if( pReadr->pIncr==0 ){
+      MergeEngine *pNew = vdbeMergeEngineNew(SORTER_MAX_MERGE_COUNT);
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM_BKPT;
+      }else{
+        rc = vdbeIncrMergerNew(pTask, pNew, &pReadr->pIncr);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      p = pReadr->pIncr->pMerger;
+      nDiv = nDiv / SORTER_MAX_MERGE_COUNT;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    p->aReadr[iSeq % SORTER_MAX_MERGE_COUNT].pIncr = pIncr;
+  }else{
+    vdbeIncrFree(pIncr);
+  }
+  return rc;
+}
+
+/*
+** This function is called as part of a SorterRewind() operation on a sorter
+** that has already written two or more level-0 PMAs to one or more temp
+** files. It builds a tree of MergeEngine/IncrMerger/PmaReader objects that
+** can be used to incrementally merge all PMAs on disk.
+**
+** If successful, SQLITE_OK is returned and *ppOut set to point to the
+** MergeEngine object at the root of the tree before returning. Or, if an
+** error occurs, an SQLite error code is returned and the final value
+** of *ppOut is undefined.
+*/
+static int vdbeSorterMergeTreeBuild(
+  VdbeSorter *pSorter,       /* The VDBE cursor that implements the sort */
+  MergeEngine **ppOut        /* Write the MergeEngine here */
+){
+  MergeEngine *pMain = 0;
+  int rc = SQLITE_OK;
+  int iTask;
+
+#if SQLITE_MAX_WORKER_THREADS>0
+  /* If the sorter uses more than one task, then create the top-level
+  ** MergeEngine here. This MergeEngine will read data from exactly
+  ** one PmaReader per sub-task.  */
+  assert( pSorter->bUseThreads || pSorter->nTask==1 );
+  if( pSorter->nTask>1 ){
+    pMain = vdbeMergeEngineNew(pSorter->nTask);
+    if( pMain==0 ) rc = SQLITE_NOMEM_BKPT;
+  }
+#endif
+
+  for(iTask=0; rc==SQLITE_OK && iTask<pSorter->nTask; iTask++){
+    SortSubtask *pTask = &pSorter->aTask[iTask];
+    assert( pTask->nPMA>0 || SQLITE_MAX_WORKER_THREADS>0 );
+    if( SQLITE_MAX_WORKER_THREADS==0 || pTask->nPMA ){
+      MergeEngine *pRoot = 0;     /* Root node of tree for this task */
+      int nDepth = vdbeSorterTreeDepth(pTask->nPMA);
+      i64 iReadOff = 0;
+
+      if( pTask->nPMA<=SORTER_MAX_MERGE_COUNT ){
+        rc = vdbeMergeEngineLevel0(pTask, pTask->nPMA, &iReadOff, &pRoot);
+      }else{
+        int i;
+        int iSeq = 0;
+        pRoot = vdbeMergeEngineNew(SORTER_MAX_MERGE_COUNT);
+        if( pRoot==0 ) rc = SQLITE_NOMEM_BKPT;
+        for(i=0; i<pTask->nPMA && rc==SQLITE_OK; i += SORTER_MAX_MERGE_COUNT){
+          MergeEngine *pMerger = 0; /* New level-0 PMA merger */
+          int nReader;              /* Number of level-0 PMAs to merge */
+
+          nReader = MIN(pTask->nPMA - i, SORTER_MAX_MERGE_COUNT);
+          rc = vdbeMergeEngineLevel0(pTask, nReader, &iReadOff, &pMerger);
+          if( rc==SQLITE_OK ){
+            rc = vdbeSorterAddToTree(pTask, nDepth, iSeq++, pRoot, pMerger);
+          }
+        }
+      }
+
+      if( rc==SQLITE_OK ){
+#if SQLITE_MAX_WORKER_THREADS>0
+        if( pMain!=0 ){
+          rc = vdbeIncrMergerNew(pTask, pRoot, &pMain->aReadr[iTask].pIncr);
+        }else
+#endif
+        {
+          assert( pMain==0 );
+          pMain = pRoot;
+        }
+      }else{
+        vdbeMergeEngineFree(pRoot);
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    vdbeMergeEngineFree(pMain);
+    pMain = 0;
+  }
+  *ppOut = pMain;
+  return rc;
+}
+
+/*
+** This function is called as part of an sqlite3VdbeSorterRewind() operation
+** on a sorter that has written two or more PMAs to temporary files. It sets
+** up either VdbeSorter.pMerger (for single threaded sorters) or pReader
+** (for multi-threaded sorters) so that it can be used to iterate through
+** all records stored in the sorter.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+static int vdbeSorterSetupMerge(VdbeSorter *pSorter){
+  int rc;                         /* Return code */
+  SortSubtask *pTask0 = &pSorter->aTask[0];
+  MergeEngine *pMain = 0;
+#if SQLITE_MAX_WORKER_THREADS
+  sqlite3 *db = pTask0->pSorter->db;
+  int i;
+  SorterCompare xCompare = vdbeSorterGetCompare(pSorter);
+  for(i=0; i<pSorter->nTask; i++){
+    pSorter->aTask[i].xCompare = xCompare;
+  }
+#endif
+
+  rc = vdbeSorterMergeTreeBuild(pSorter, &pMain);
+  if( rc==SQLITE_OK ){
+#if SQLITE_MAX_WORKER_THREADS
+    assert( pSorter->bUseThreads==0 || pSorter->nTask>1 );
+    if( pSorter->bUseThreads ){
+      int iTask;
+      PmaReader *pReadr = 0;
+      SortSubtask *pLast = &pSorter->aTask[pSorter->nTask-1];
+      rc = vdbeSortAllocUnpacked(pLast);
+      if( rc==SQLITE_OK ){
+        pReadr = (PmaReader*)sqlite3DbMallocZero(db, sizeof(PmaReader));
+        pSorter->pReader = pReadr;
+        if( pReadr==0 ) rc = SQLITE_NOMEM_BKPT;
+      }
+      if( rc==SQLITE_OK ){
+        rc = vdbeIncrMergerNew(pLast, pMain, &pReadr->pIncr);
+        if( rc==SQLITE_OK ){
+          vdbeIncrMergerSetThreads(pReadr->pIncr);
+          for(iTask=0; iTask<(pSorter->nTask-1); iTask++){
+            IncrMerger *pIncr;
+            if( (pIncr = pMain->aReadr[iTask].pIncr) ){
+              vdbeIncrMergerSetThreads(pIncr);
+              assert( pIncr->pTask!=pLast );
+            }
+          }
+          for(iTask=0; rc==SQLITE_OK && iTask<pSorter->nTask; iTask++){
+            /* Check that:
+            **
+            **   a) The incremental merge object is configured to use the
+            **      right task, and
+            **   b) If it is using task (nTask-1), it is configured to run
+            **      in single-threaded mode. This is important, as the
+            **      root merge (INCRINIT_ROOT) will be using the same task
+            **      object.
+            */
+            PmaReader *p = &pMain->aReadr[iTask];
+            assert( p->pIncr==0 || (
+                (p->pIncr->pTask==&pSorter->aTask[iTask])             /* a */
+             && (iTask!=pSorter->nTask-1 || p->pIncr->bUseThread==0)  /* b */
+            ));
+            rc = vdbePmaReaderIncrInit(p, INCRINIT_TASK);
+          }
+        }
+        pMain = 0;
+      }
+      if( rc==SQLITE_OK ){
+        rc = vdbePmaReaderIncrMergeInit(pReadr, INCRINIT_ROOT);
+      }
+    }else
+#endif
+    {
+      rc = vdbeMergeEngineInit(pTask0, pMain, INCRINIT_NORMAL);
+      pSorter->pMerger = pMain;
+      pMain = 0;
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    vdbeMergeEngineFree(pMain);
+  }
+  return rc;
+}
+
+
+/*
+** Once the sorter has been populated by calls to sqlite3VdbeSorterWrite,
+** this function is called to prepare for iterating through the records
+** in sorted order.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterRewind(const VdbeCursor *pCsr, int *pbEof){
+  VdbeSorter *pSorter;
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  assert( pSorter );
+
+  /* If no data has been written to disk, then do not do so now. Instead,
+  ** sort the VdbeSorter.pRecord list. The vdbe layer will read data directly
+  ** from the in-memory list.  */
+  if( pSorter->bUsePMA==0 ){
+    if( pSorter->list.pList ){
+      *pbEof = 0;
+      rc = vdbeSorterSort(&pSorter->aTask[0], &pSorter->list);
+    }else{
+      *pbEof = 1;
+    }
+    return rc;
+  }
+
+  /* Write the current in-memory list to a PMA. When the VdbeSorterWrite()
+  ** function flushes the contents of memory to disk, it immediately always
+  ** creates a new list consisting of a single key immediately afterwards.
+  ** So the list is never empty at this point.  */
+  assert( pSorter->list.pList );
+  rc = vdbeSorterFlushPMA(pSorter);
+
+  /* Join all threads */
+  rc = vdbeSorterJoinAll(pSorter, rc);
+
+  vdbeSorterRewindDebug("rewind");
+
+  /* Assuming no errors have occurred, set up a merger structure to
+  ** incrementally read and merge all remaining PMAs.  */
+  assert( pSorter->pReader==0 );
+  if( rc==SQLITE_OK ){
+    rc = vdbeSorterSetupMerge(pSorter);
+    *pbEof = 0;
+  }
+
+  vdbeSorterRewindDebug("rewinddone");
+  return rc;
+}
+
+/*
+** Advance to the next element in the sorter.  Return value:
+**
+**    SQLITE_OK     success
+**    SQLITE_DONE   end of data
+**    otherwise     some kind of error.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterNext(sqlite3 *db, const VdbeCursor *pCsr){
+  VdbeSorter *pSorter;
+  int rc;                         /* Return code */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  assert( pSorter->bUsePMA || (pSorter->pReader==0 && pSorter->pMerger==0) );
+  if( pSorter->bUsePMA ){
+    assert( pSorter->pReader==0 || pSorter->pMerger==0 );
+    assert( pSorter->bUseThreads==0 || pSorter->pReader );
+    assert( pSorter->bUseThreads==1 || pSorter->pMerger );
+#if SQLITE_MAX_WORKER_THREADS>0
+    if( pSorter->bUseThreads ){
+      rc = vdbePmaReaderNext(pSorter->pReader);
+      if( rc==SQLITE_OK && pSorter->pReader->pFd==0 ) rc = SQLITE_DONE;
+    }else
+#endif
+    /*if( !pSorter->bUseThreads )*/ {
+      int res = 0;
+      assert( pSorter->pMerger!=0 );
+      assert( pSorter->pMerger->pTask==(&pSorter->aTask[0]) );
+      rc = vdbeMergeEngineStep(pSorter->pMerger, &res);
+      if( rc==SQLITE_OK && res ) rc = SQLITE_DONE;
+    }
+  }else{
+    SorterRecord *pFree = pSorter->list.pList;
+    pSorter->list.pList = pFree->u.pNext;
+    pFree->u.pNext = 0;
+    if( pSorter->list.aMemory==0 ) vdbeSorterRecordFree(db, pFree);
+    rc = pSorter->list.pList ? SQLITE_OK : SQLITE_DONE;
+  }
+  return rc;
+}
+
+/*
+** Return a pointer to a buffer owned by the sorter that contains the
+** current key.
+*/
+static void *vdbeSorterRowkey(
+  const VdbeSorter *pSorter,      /* Sorter object */
+  int *pnKey                      /* OUT: Size of current key in bytes */
+){
+  void *pKey;
+  if( pSorter->bUsePMA ){
+    PmaReader *pReader;
+#if SQLITE_MAX_WORKER_THREADS>0
+    if( pSorter->bUseThreads ){
+      pReader = pSorter->pReader;
+    }else
+#endif
+    /*if( !pSorter->bUseThreads )*/{
+      pReader = &pSorter->pMerger->aReadr[pSorter->pMerger->aTree[1]];
+    }
+    *pnKey = pReader->nKey;
+    pKey = pReader->aKey;
+  }else{
+    *pnKey = pSorter->list.pList->nVal;
+    pKey = SRVAL(pSorter->list.pList);
+  }
+  return pKey;
+}
+
+/*
+** Copy the current sorter key into the memory cell pOut.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(const VdbeCursor *pCsr, Mem *pOut){
+  VdbeSorter *pSorter;
+  void *pKey; int nKey;           /* Sorter key to copy into pOut */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  pKey = vdbeSorterRowkey(pSorter, &nKey);
+  if( sqlite3VdbeMemClearAndResize(pOut, nKey) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  pOut->n = nKey;
+  MemSetTypeFlag(pOut, MEM_Blob);
+  memcpy(pOut->z, pKey, nKey);
+
+  return SQLITE_OK;
+}
+
+/*
+** Compare the key in memory cell pVal with the key that the sorter cursor
+** passed as the first argument currently points to. For the purposes of
+** the comparison, ignore the rowid field at the end of each record.
+**
+** If the sorter cursor key contains any NULL values, consider it to be
+** less than pVal. Even if pVal also contains NULL values.
+**
+** If an error occurs, return an SQLite error code (i.e. SQLITE_NOMEM).
+** Otherwise, set *pRes to a negative, zero or positive value if the
+** key in pVal is smaller than, equal to or larger than the current sorter
+** key.
+**
+** This routine forms the core of the OP_SorterCompare opcode, which in
+** turn is used to verify uniqueness when constructing a UNIQUE INDEX.
+*/
+SQLITE_PRIVATE int sqlite3VdbeSorterCompare(
+  const VdbeCursor *pCsr,         /* Sorter cursor */
+  Mem *pVal,                      /* Value to compare to current sorter key */
+  int nKeyCol,                    /* Compare this many columns */
+  int *pRes                       /* OUT: Result of comparison */
+){
+  VdbeSorter *pSorter;
+  UnpackedRecord *r2;
+  KeyInfo *pKeyInfo;
+  int i;
+  void *pKey; int nKey;           /* Sorter key to compare pVal with */
+
+  assert( pCsr->eCurType==CURTYPE_SORTER );
+  pSorter = pCsr->uc.pSorter;
+  r2 = pSorter->pUnpacked;
+  pKeyInfo = pCsr->pKeyInfo;
+  if( r2==0 ){
+    r2 = pSorter->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
+    if( r2==0 ) return SQLITE_NOMEM_BKPT;
+    r2->nField = nKeyCol;
+  }
+  assert( r2->nField==nKeyCol );
+
+  pKey = vdbeSorterRowkey(pSorter, &nKey);
+  sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, r2);
+  for(i=0; i<nKeyCol; i++){
+    if( r2->aMem[i].flags & MEM_Null ){
+      *pRes = -1;
+      return SQLITE_OK;
+    }
+  }
+
+  *pRes = sqlite3VdbeRecordCompare(pVal->n, pVal->z, r2);
+  return SQLITE_OK;
+}
+
+/************** End of vdbesort.c ********************************************/
+/************** Begin file vdbevtab.c ****************************************/
+/*
+** 2020-03-23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements virtual-tables for examining the bytecode content
+** of a prepared statement.
+*/
+/* #include "sqliteInt.h" */
+#if defined(SQLITE_ENABLE_BYTECODE_VTAB) && !defined(SQLITE_OMIT_VIRTUALTABLE)
+/* #include "vdbeInt.h" */
+
+/* An instance of the bytecode() table-valued function.
+*/
+typedef struct bytecodevtab bytecodevtab;
+struct bytecodevtab {
+  sqlite3_vtab base;     /* Base class - must be first */
+  sqlite3 *db;           /* Database connection */
+  int bTablesUsed;       /* 2 for tables_used().  0 for bytecode(). */
+};
+
+/* A cursor for scanning through the bytecode
+*/
+typedef struct bytecodevtab_cursor bytecodevtab_cursor;
+struct bytecodevtab_cursor {
+  sqlite3_vtab_cursor base;  /* Base class - must be first */
+  sqlite3_stmt *pStmt;       /* The statement whose bytecode is displayed */
+  int iRowid;                /* The rowid of the output table */
+  int iAddr;                 /* Address */
+  int needFinalize;          /* Cursors owns pStmt and must finalize it */
+  int showSubprograms;       /* Provide a listing of subprograms */
+  Op *aOp;                   /* Operand array */
+  char *zP4;                 /* Rendered P4 value */
+  const char *zType;         /* tables_used.type */
+  const char *zSchema;       /* tables_used.schema */
+  const char *zName;         /* tables_used.name */
+  Mem sub;                   /* Subprograms */
+};
+
+/*
+** Create a new bytecode() table-valued function.
+*/
+static int bytecodevtabConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  bytecodevtab *pNew;
+  int rc;
+  int isTabUsed = pAux!=0;
+  const char *azSchema[2] = {
+    /* bytecode() schema */
+    "CREATE TABLE x("
+      "addr INT,"
+      "opcode TEXT,"
+      "p1 INT,"
+      "p2 INT,"
+      "p3 INT,"
+      "p4 TEXT,"
+      "p5 INT,"
+      "comment TEXT,"
+      "subprog TEXT,"
+      "nexec INT,"
+      "ncycle INT,"
+      "stmt HIDDEN"
+    ");",
+
+    /* Tables_used() schema */
+    "CREATE TABLE x("
+      "type TEXT,"
+      "schema TEXT,"
+      "name TEXT,"
+      "wr INT,"
+      "subprog TEXT,"
+      "stmt HIDDEN"
+   ");"
+  };
+
+  (void)argc;
+  (void)argv;
+  (void)pzErr;
+  rc = sqlite3_declare_vtab(db, azSchema[isTabUsed]);
+  if( rc==SQLITE_OK ){
+    pNew = sqlite3_malloc( sizeof(*pNew) );
+    *ppVtab = (sqlite3_vtab*)pNew;
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, sizeof(*pNew));
+    pNew->db = db;
+    pNew->bTablesUsed = isTabUsed*2;
+  }
+  return rc;
+}
+
+/*
+** This method is the destructor for bytecodevtab objects.
+*/
+static int bytecodevtabDisconnect(sqlite3_vtab *pVtab){
+  bytecodevtab *p = (bytecodevtab*)pVtab;
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Constructor for a new bytecodevtab_cursor object.
+*/
+static int bytecodevtabOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+  bytecodevtab *pVTab = (bytecodevtab*)p;
+  bytecodevtab_cursor *pCur;
+  pCur = sqlite3_malloc( sizeof(*pCur) );
+  if( pCur==0 ) return SQLITE_NOMEM;
+  memset(pCur, 0, sizeof(*pCur));
+  sqlite3VdbeMemInit(&pCur->sub, pVTab->db, 1);
+  *ppCursor = &pCur->base;
+  return SQLITE_OK;
+}
+
+/*
+** Clear all internal content from a bytecodevtab cursor.
+*/
+static void bytecodevtabCursorClear(bytecodevtab_cursor *pCur){
+  sqlite3_free(pCur->zP4);
+  pCur->zP4 = 0;
+  sqlite3VdbeMemRelease(&pCur->sub);
+  sqlite3VdbeMemSetNull(&pCur->sub);
+  if( pCur->needFinalize ){
+    sqlite3_finalize(pCur->pStmt);
+  }
+  pCur->pStmt = 0;
+  pCur->needFinalize = 0;
+  pCur->zType = 0;
+  pCur->zSchema = 0;
+  pCur->zName = 0;
+}
+
+/*
+** Destructor for a bytecodevtab_cursor.
+*/
+static int bytecodevtabClose(sqlite3_vtab_cursor *cur){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  bytecodevtabCursorClear(pCur);
+  sqlite3_free(pCur);
+  return SQLITE_OK;
+}
+
+
+/*
+** Advance a bytecodevtab_cursor to its next row of output.
+*/
+static int bytecodevtabNext(sqlite3_vtab_cursor *cur){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  bytecodevtab *pTab = (bytecodevtab*)cur->pVtab;
+  int rc;
+  if( pCur->zP4 ){
+    sqlite3_free(pCur->zP4);
+    pCur->zP4 = 0;
+  }
+  if( pCur->zName ){
+    pCur->zName = 0;
+    pCur->zType = 0;
+    pCur->zSchema = 0;
+  }
+  rc = sqlite3VdbeNextOpcode(
+           (Vdbe*)pCur->pStmt,
+           pCur->showSubprograms ? &pCur->sub : 0,
+           pTab->bTablesUsed,
+           &pCur->iRowid,
+           &pCur->iAddr,
+           &pCur->aOp);
+  if( rc!=SQLITE_OK ){
+    sqlite3VdbeMemSetNull(&pCur->sub);
+    pCur->aOp = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the cursor has been moved off of the last
+** row of output.
+*/
+static int bytecodevtabEof(sqlite3_vtab_cursor *cur){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  return pCur->aOp==0;
+}
+
+/*
+** Return values of columns for the row at which the bytecodevtab_cursor
+** is currently pointing.
+*/
+static int bytecodevtabColumn(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int i                       /* Which column to return */
+){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  bytecodevtab *pVTab = (bytecodevtab*)cur->pVtab;
+  Op *pOp = pCur->aOp + pCur->iAddr;
+  if( pVTab->bTablesUsed ){
+    if( i==4 ){
+      i = 8;
+    }else{
+      if( i<=2 && pCur->zType==0 ){
+        Schema *pSchema;
+        HashElem *k;
+        int iDb = pOp->p3;
+        Pgno iRoot = (Pgno)pOp->p2;
+        sqlite3 *db = pVTab->db;
+        pSchema = db->aDb[iDb].pSchema;
+        pCur->zSchema = db->aDb[iDb].zDbSName;
+        for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
+          Table *pTab = (Table*)sqliteHashData(k);
+          if( !IsVirtual(pTab) && pTab->tnum==iRoot ){
+            pCur->zName = pTab->zName;
+            pCur->zType = "table";
+            break;
+          }
+        }
+        if( pCur->zName==0 ){
+          for(k=sqliteHashFirst(&pSchema->idxHash); k; k=sqliteHashNext(k)){
+            Index *pIdx = (Index*)sqliteHashData(k);
+            if( pIdx->tnum==iRoot ){
+              pCur->zName = pIdx->zName;
+              pCur->zType = "index";
+            }
+          }
+        }
+      }
+      i += 20;
+    }
+  }
+  switch( i ){
+    case 0:   /* addr */
+      sqlite3_result_int(ctx, pCur->iAddr);
+      break;
+    case 1:   /* opcode */
+      sqlite3_result_text(ctx, (char*)sqlite3OpcodeName(pOp->opcode),
+                          -1, SQLITE_STATIC);
+      break;
+    case 2:   /* p1 */
+      sqlite3_result_int(ctx, pOp->p1);
+      break;
+    case 3:   /* p2 */
+      sqlite3_result_int(ctx, pOp->p2);
+      break;
+    case 4:   /* p3 */
+      sqlite3_result_int(ctx, pOp->p3);
+      break;
+    case 5:   /* p4 */
+    case 7:   /* comment */
+      if( pCur->zP4==0 ){
+        pCur->zP4 = sqlite3VdbeDisplayP4(pVTab->db, pOp);
+      }
+      if( i==5 ){
+        sqlite3_result_text(ctx, pCur->zP4, -1, SQLITE_STATIC);
+      }else{
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+        char *zCom = sqlite3VdbeDisplayComment(pVTab->db, pOp, pCur->zP4);
+        sqlite3_result_text(ctx, zCom, -1, sqlite3_free);
+#endif
+      }
+      break;
+    case 6:     /* p5 */
+      sqlite3_result_int(ctx, pOp->p5);
+      break;
+    case 8: {   /* subprog */
+      Op *aOp = pCur->aOp;
+      assert( aOp[0].opcode==OP_Init );
+      assert( aOp[0].p4.z==0 || strncmp(aOp[0].p4.z,"-" "- ",3)==0 );
+      if( pCur->iRowid==pCur->iAddr+1 ){
+        break;  /* Result is NULL for the main program */
+      }else if( aOp[0].p4.z!=0 ){
+         sqlite3_result_text(ctx, aOp[0].p4.z+3, -1, SQLITE_STATIC);
+      }else{
+         sqlite3_result_text(ctx, "(FK)", 4, SQLITE_STATIC);
+      }
+      break;
+    }
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+    case 9:     /* nexec */
+      sqlite3_result_int64(ctx, pOp->nExec);
+      break;
+    case 10:    /* ncycle */
+      sqlite3_result_int64(ctx, pOp->nCycle);
+      break;
+#else
+    case 9:     /* nexec */
+    case 10:    /* ncycle */
+      sqlite3_result_int(ctx, 0);
+      break;
+#endif
+
+    case 20:  /* tables_used.type */
+      sqlite3_result_text(ctx, pCur->zType, -1, SQLITE_STATIC);
+      break;
+    case 21:  /* tables_used.schema */
+      sqlite3_result_text(ctx, pCur->zSchema, -1, SQLITE_STATIC);
+      break;
+    case 22:  /* tables_used.name */
+      sqlite3_result_text(ctx, pCur->zName, -1, SQLITE_STATIC);
+      break;
+    case 23:  /* tables_used.wr */
+      sqlite3_result_int(ctx, pOp->opcode==OP_OpenWrite);
+      break;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return the rowid for the current row.  In this implementation, the
+** rowid is the same as the output value.
+*/
+static int bytecodevtabRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
+  *pRowid = pCur->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Initialize a cursor.
+**
+**    idxNum==0     means show all subprograms
+**    idxNum==1     means show only the main bytecode and omit subprograms.
+*/
+static int bytecodevtabFilter(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  bytecodevtab_cursor *pCur = (bytecodevtab_cursor *)pVtabCursor;
+  bytecodevtab *pVTab = (bytecodevtab *)pVtabCursor->pVtab;
+  int rc = SQLITE_OK;
+  (void)idxStr;
+
+  bytecodevtabCursorClear(pCur);
+  pCur->iRowid = 0;
+  pCur->iAddr = 0;
+  pCur->showSubprograms = idxNum==0;
+  assert( argc==1 );
+  if( sqlite3_value_type(argv[0])==SQLITE_TEXT ){
+    const char *zSql = (const char*)sqlite3_value_text(argv[0]);
+    if( zSql==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(pVTab->db, zSql, -1, &pCur->pStmt, 0);
+      pCur->needFinalize = 1;
+    }
+  }else{
+    pCur->pStmt = (sqlite3_stmt*)sqlite3_value_pointer(argv[0],"stmt-pointer");
+  }
+  if( pCur->pStmt==0 ){
+    pVTab->base.zErrMsg = sqlite3_mprintf(
+       "argument to %s() is not a valid SQL statement",
+       pVTab->bTablesUsed ? "tables_used" : "bytecode"
+    );
+    rc = SQLITE_ERROR;
+  }else{
+    bytecodevtabNext(pVtabCursor);
+  }
+  return rc;
+}
+
+/*
+** We must have a single stmt=? constraint that will be passed through
+** into the xFilter method.  If there is no valid stmt=? constraint,
+** then return an SQLITE_CONSTRAINT error.
+*/
+static int bytecodevtabBestIndex(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  int i;
+  int rc = SQLITE_CONSTRAINT;
+  struct sqlite3_index_constraint *p;
+  bytecodevtab *pVTab = (bytecodevtab*)tab;
+  int iBaseCol = pVTab->bTablesUsed ? 4 : 10;
+  pIdxInfo->estimatedCost = (double)100;
+  pIdxInfo->estimatedRows = 100;
+  pIdxInfo->idxNum = 0;
+  for(i=0, p=pIdxInfo->aConstraint; i<pIdxInfo->nConstraint; i++, p++){
+    if( p->usable==0 ) continue;
+    if( p->op==SQLITE_INDEX_CONSTRAINT_EQ && p->iColumn==iBaseCol+1 ){
+      rc = SQLITE_OK;
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
+    }
+    if( p->op==SQLITE_INDEX_CONSTRAINT_ISNULL && p->iColumn==iBaseCol ){
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      pIdxInfo->idxNum = 1;
+    }
+  }
+  return rc;
+}
+
+/*
+** This following structure defines all the methods for the
+** virtual table.
+*/
+static sqlite3_module bytecodevtabModule = {
+  /* iVersion    */ 0,
+  /* xCreate     */ 0,
+  /* xConnect    */ bytecodevtabConnect,
+  /* xBestIndex  */ bytecodevtabBestIndex,
+  /* xDisconnect */ bytecodevtabDisconnect,
+  /* xDestroy    */ 0,
+  /* xOpen       */ bytecodevtabOpen,
+  /* xClose      */ bytecodevtabClose,
+  /* xFilter     */ bytecodevtabFilter,
+  /* xNext       */ bytecodevtabNext,
+  /* xEof        */ bytecodevtabEof,
+  /* xColumn     */ bytecodevtabColumn,
+  /* xRowid      */ bytecodevtabRowid,
+  /* xUpdate     */ 0,
+  /* xBegin      */ 0,
+  /* xSync       */ 0,
+  /* xCommit     */ 0,
+  /* xRollback   */ 0,
+  /* xFindMethod */ 0,
+  /* xRename     */ 0,
+  /* xSavepoint  */ 0,
+  /* xRelease    */ 0,
+  /* xRollbackTo */ 0,
+  /* xShadowName */ 0,
+  /* xIntegrity  */ 0
+};
+
+
+SQLITE_PRIVATE int sqlite3VdbeBytecodeVtabInit(sqlite3 *db){
+  int rc;
+  rc = sqlite3_create_module(db, "bytecode", &bytecodevtabModule, 0);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_module(db, "tables_used", &bytecodevtabModule, &db);
+  }
+  return rc;
+}
+#elif defined(SQLITE_ENABLE_BYTECODE_VTAB)
+SQLITE_PRIVATE int sqlite3VdbeBytecodeVtabInit(sqlite3 *db){ return SQLITE_OK; }
+#endif /* SQLITE_ENABLE_BYTECODE_VTAB */
+
+/************** End of vdbevtab.c ********************************************/
+/************** Begin file memjournal.c **************************************/
+/*
+** 2008 October 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains code use to implement an in-memory rollback journal.
+** The in-memory rollback journal is used to journal transactions for
+** ":memory:" databases and when the journal_mode=MEMORY pragma is used.
+**
+** Update:  The in-memory journal is also used to temporarily cache
+** smaller journals that are not critical for power-loss recovery.
+** For example, statement journals that are not too big will be held
+** entirely in memory, thus reducing the number of file I/O calls, and
+** more importantly, reducing temporary file creation events.  If these
+** journals become too large for memory, they are spilled to disk.  But
+** in the common case, they are usually small and no file I/O needs to
+** occur.
+*/
+/* #include "sqliteInt.h" */
+
+/* Forward references to internal structures */
+typedef struct MemJournal MemJournal;
+typedef struct FilePoint FilePoint;
+typedef struct FileChunk FileChunk;
+
+/*
+** The rollback journal is composed of a linked list of these structures.
+**
+** The zChunk array is always at least 8 bytes in size - usually much more.
+** Its actual size is stored in the MemJournal.nChunkSize variable.
+*/
+struct FileChunk {
+  FileChunk *pNext;               /* Next chunk in the journal */
+  u8 zChunk[8];                   /* Content of this chunk */
+};
+
+/*
+** By default, allocate this many bytes of memory for each FileChunk object.
+*/
+#define MEMJOURNAL_DFLT_FILECHUNKSIZE 1024
+
+/*
+** For chunk size nChunkSize, return the number of bytes that should
+** be allocated for each FileChunk structure.
+*/
+#define fileChunkSize(nChunkSize) (sizeof(FileChunk) + ((nChunkSize)-8))
+
+/*
+** An instance of this object serves as a cursor into the rollback journal.
+** The cursor can be either for reading or writing.
+*/
+struct FilePoint {
+  sqlite3_int64 iOffset;          /* Offset from the beginning of the file */
+  FileChunk *pChunk;              /* Specific chunk into which cursor points */
+};
+
+/*
+** This structure is a subclass of sqlite3_file. Each open memory-journal
+** is an instance of this class.
+*/
+struct MemJournal {
+  const sqlite3_io_methods *pMethod; /* Parent class. MUST BE FIRST */
+  int nChunkSize;                 /* In-memory chunk-size */
+
+  int nSpill;                     /* Bytes of data before flushing */
+  FileChunk *pFirst;              /* Head of in-memory chunk-list */
+  FilePoint endpoint;             /* Pointer to the end of the file */
+  FilePoint readpoint;            /* Pointer to the end of the last xRead() */
+
+  int flags;                      /* xOpen flags */
+  sqlite3_vfs *pVfs;              /* The "real" underlying VFS */
+  const char *zJournal;           /* Name of the journal file */
+};
+
+/*
+** Read data from the in-memory journal file.  This is the implementation
+** of the sqlite3_vfs.xRead method.
+*/
+static int memjrnlRead(
+  sqlite3_file *pJfd,    /* The journal file from which to read */
+  void *zBuf,            /* Put the results here */
+  int iAmt,              /* Number of bytes to read */
+  sqlite_int64 iOfst     /* Begin reading at this offset */
+){
+  MemJournal *p = (MemJournal *)pJfd;
+  u8 *zOut = zBuf;
+  int nRead = iAmt;
+  int iChunkOffset;
+  FileChunk *pChunk;
+
+  if( (iAmt+iOfst)>p->endpoint.iOffset ){
+    return SQLITE_IOERR_SHORT_READ;
+  }
+  assert( p->readpoint.iOffset==0 || p->readpoint.pChunk!=0 );
+  if( p->readpoint.iOffset!=iOfst || iOfst==0 ){
+    sqlite3_int64 iOff = 0;
+    for(pChunk=p->pFirst;
+        ALWAYS(pChunk) && (iOff+p->nChunkSize)<=iOfst;
+        pChunk=pChunk->pNext
+    ){
+      iOff += p->nChunkSize;
+    }
+  }else{
+    pChunk = p->readpoint.pChunk;
+    assert( pChunk!=0 );
+  }
+
+  iChunkOffset = (int)(iOfst%p->nChunkSize);
+  do {
+    int iSpace = p->nChunkSize - iChunkOffset;
+    int nCopy = MIN(nRead, (p->nChunkSize - iChunkOffset));
+    memcpy(zOut, (u8*)pChunk->zChunk + iChunkOffset, nCopy);
+    zOut += nCopy;
+    nRead -= iSpace;
+    iChunkOffset = 0;
+  } while( nRead>=0 && (pChunk=pChunk->pNext)!=0 && nRead>0 );
+  p->readpoint.iOffset = pChunk ? iOfst+iAmt : 0;
+  p->readpoint.pChunk = pChunk;
+
+  return SQLITE_OK;
+}
+
+/*
+** Free the list of FileChunk structures headed at MemJournal.pFirst.
+*/
+static void memjrnlFreeChunks(FileChunk *pFirst){
+  FileChunk *pIter;
+  FileChunk *pNext;
+  for(pIter=pFirst; pIter; pIter=pNext){
+    pNext = pIter->pNext;
+    sqlite3_free(pIter);
+  }
+}
+
+/*
+** Flush the contents of memory to a real file on disk.
+*/
+static int memjrnlCreateFile(MemJournal *p){
+  int rc;
+  sqlite3_file *pReal = (sqlite3_file*)p;
+  MemJournal copy = *p;
+
+  memset(p, 0, sizeof(MemJournal));
+  rc = sqlite3OsOpen(copy.pVfs, copy.zJournal, pReal, copy.flags, 0);
+  if( rc==SQLITE_OK ){
+    int nChunk = copy.nChunkSize;
+    i64 iOff = 0;
+    FileChunk *pIter;
+    for(pIter=copy.pFirst; pIter; pIter=pIter->pNext){
+      if( iOff + nChunk > copy.endpoint.iOffset ){
+        nChunk = copy.endpoint.iOffset - iOff;
+      }
+      rc = sqlite3OsWrite(pReal, (u8*)pIter->zChunk, nChunk, iOff);
+      if( rc ) break;
+      iOff += nChunk;
+    }
+    if( rc==SQLITE_OK ){
+      /* No error has occurred. Free the in-memory buffers. */
+      memjrnlFreeChunks(copy.pFirst);
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    /* If an error occurred while creating or writing to the file, restore
+    ** the original before returning. This way, SQLite uses the in-memory
+    ** journal data to roll back changes made to the internal page-cache
+    ** before this function was called.  */
+    sqlite3OsClose(pReal);
+    *p = copy;
+  }
+  return rc;
+}
+
+
+/* Forward reference */
+static int memjrnlTruncate(sqlite3_file *pJfd, sqlite_int64 size);
+
+/*
+** Write data to the file.
+*/
+static int memjrnlWrite(
+  sqlite3_file *pJfd,    /* The journal file into which to write */
+  const void *zBuf,      /* Take data to be written from here */
+  int iAmt,              /* Number of bytes to write */
+  sqlite_int64 iOfst     /* Begin writing at this offset into the file */
+){
+  MemJournal *p = (MemJournal *)pJfd;
+  int nWrite = iAmt;
+  u8 *zWrite = (u8 *)zBuf;
+
+  /* If the file should be created now, create it and write the new data
+  ** into the file on disk. */
+  if( p->nSpill>0 && (iAmt+iOfst)>p->nSpill ){
+    int rc = memjrnlCreateFile(p);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3OsWrite(pJfd, zBuf, iAmt, iOfst);
+    }
+    return rc;
+  }
+
+  /* If the contents of this write should be stored in memory */
+  else{
+    /* An in-memory journal file should only ever be appended to. Random
+    ** access writes are not required. The only exception to this is when
+    ** the in-memory journal is being used by a connection using the
+    ** atomic-write optimization. In this case the first 28 bytes of the
+    ** journal file may be written as part of committing the transaction. */
+    assert( iOfst<=p->endpoint.iOffset );
+    if( iOfst>0 && iOfst!=p->endpoint.iOffset ){
+      memjrnlTruncate(pJfd, iOfst);
+    }
+    if( iOfst==0 && p->pFirst ){
+      assert( p->nChunkSize>iAmt );
+      memcpy((u8*)p->pFirst->zChunk, zBuf, iAmt);
+    }else{
+      while( nWrite>0 ){
+        FileChunk *pChunk = p->endpoint.pChunk;
+        int iChunkOffset = (int)(p->endpoint.iOffset%p->nChunkSize);
+        int iSpace = MIN(nWrite, p->nChunkSize - iChunkOffset);
+
+        assert( pChunk!=0 || iChunkOffset==0 );
+        if( iChunkOffset==0 ){
+          /* New chunk is required to extend the file. */
+          FileChunk *pNew = sqlite3_malloc(fileChunkSize(p->nChunkSize));
+          if( !pNew ){
+            return SQLITE_IOERR_NOMEM_BKPT;
+          }
+          pNew->pNext = 0;
+          if( pChunk ){
+            assert( p->pFirst );
+            pChunk->pNext = pNew;
+          }else{
+            assert( !p->pFirst );
+            p->pFirst = pNew;
+          }
+          pChunk = p->endpoint.pChunk = pNew;
+        }
+
+        assert( pChunk!=0 );
+        memcpy((u8*)pChunk->zChunk + iChunkOffset, zWrite, iSpace);
+        zWrite += iSpace;
+        nWrite -= iSpace;
+        p->endpoint.iOffset += iSpace;
+      }
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Truncate the in-memory file.
+*/
+static int memjrnlTruncate(sqlite3_file *pJfd, sqlite_int64 size){
+  MemJournal *p = (MemJournal *)pJfd;
+  assert( p->endpoint.pChunk==0 || p->endpoint.pChunk->pNext==0 );
+  if( size<p->endpoint.iOffset ){
+    FileChunk *pIter = 0;
+    if( size==0 ){
+      memjrnlFreeChunks(p->pFirst);
+      p->pFirst = 0;
+    }else{
+      i64 iOff = p->nChunkSize;
+      for(pIter=p->pFirst; ALWAYS(pIter) && iOff<size; pIter=pIter->pNext){
+        iOff += p->nChunkSize;
+      }
+      if( ALWAYS(pIter) ){
+        memjrnlFreeChunks(pIter->pNext);
+        pIter->pNext = 0;
+      }
+    }
+
+    p->endpoint.pChunk = pIter;
+    p->endpoint.iOffset = size;
+    p->readpoint.pChunk = 0;
+    p->readpoint.iOffset = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Close the file.
+*/
+static int memjrnlClose(sqlite3_file *pJfd){
+  MemJournal *p = (MemJournal *)pJfd;
+  memjrnlFreeChunks(p->pFirst);
+  return SQLITE_OK;
+}
+
+/*
+** Sync the file.
+**
+** If the real file has been created, call its xSync method. Otherwise,
+** syncing an in-memory journal is a no-op.
+*/
+static int memjrnlSync(sqlite3_file *pJfd, int flags){
+  UNUSED_PARAMETER2(pJfd, flags);
+  return SQLITE_OK;
+}
+
+/*
+** Query the size of the file in bytes.
+*/
+static int memjrnlFileSize(sqlite3_file *pJfd, sqlite_int64 *pSize){
+  MemJournal *p = (MemJournal *)pJfd;
+  *pSize = (sqlite_int64) p->endpoint.iOffset;
+  return SQLITE_OK;
+}
+
+/*
+** Table of methods for MemJournal sqlite3_file object.
+*/
+static const struct sqlite3_io_methods MemJournalMethods = {
+  1,                /* iVersion */
+  memjrnlClose,     /* xClose */
+  memjrnlRead,      /* xRead */
+  memjrnlWrite,     /* xWrite */
+  memjrnlTruncate,  /* xTruncate */
+  memjrnlSync,      /* xSync */
+  memjrnlFileSize,  /* xFileSize */
+  0,                /* xLock */
+  0,                /* xUnlock */
+  0,                /* xCheckReservedLock */
+  0,                /* xFileControl */
+  0,                /* xSectorSize */
+  0,                /* xDeviceCharacteristics */
+  0,                /* xShmMap */
+  0,                /* xShmLock */
+  0,                /* xShmBarrier */
+  0,                /* xShmUnmap */
+  0,                /* xFetch */
+  0                 /* xUnfetch */
+};
+
+/*
+** Open a journal file.
+**
+** The behaviour of the journal file depends on the value of parameter
+** nSpill. If nSpill is 0, then the journal file is always create and
+** accessed using the underlying VFS. If nSpill is less than zero, then
+** all content is always stored in main-memory. Finally, if nSpill is a
+** positive value, then the journal file is initially created in-memory
+** but may be flushed to disk later on. In this case the journal file is
+** flushed to disk either when it grows larger than nSpill bytes in size,
+** or when sqlite3JournalCreate() is called.
+*/
+SQLITE_PRIVATE int sqlite3JournalOpen(
+  sqlite3_vfs *pVfs,         /* The VFS to use for actual file I/O */
+  const char *zName,         /* Name of the journal file */
+  sqlite3_file *pJfd,        /* Preallocated, blank file handle */
+  int flags,                 /* Opening flags */
+  int nSpill                 /* Bytes buffered before opening the file */
+){
+  MemJournal *p = (MemJournal*)pJfd;
+
+  assert( zName || nSpill<0 || (flags & SQLITE_OPEN_EXCLUSIVE) );
+
+  /* Zero the file-handle object. If nSpill was passed zero, initialize
+  ** it using the sqlite3OsOpen() function of the underlying VFS. In this
+  ** case none of the code in this module is executed as a result of calls
+  ** made on the journal file-handle.  */
+  memset(p, 0, sizeof(MemJournal));
+  if( nSpill==0 ){
+    return sqlite3OsOpen(pVfs, zName, pJfd, flags, 0);
+  }
+
+  if( nSpill>0 ){
+    p->nChunkSize = nSpill;
+  }else{
+    p->nChunkSize = 8 + MEMJOURNAL_DFLT_FILECHUNKSIZE - sizeof(FileChunk);
+    assert( MEMJOURNAL_DFLT_FILECHUNKSIZE==fileChunkSize(p->nChunkSize) );
+  }
+
+  pJfd->pMethods = (const sqlite3_io_methods*)&MemJournalMethods;
+  p->nSpill = nSpill;
+  p->flags = flags;
+  p->zJournal = zName;
+  p->pVfs = pVfs;
+  return SQLITE_OK;
+}
+
+/*
+** Open an in-memory journal file.
+*/
+SQLITE_PRIVATE void sqlite3MemJournalOpen(sqlite3_file *pJfd){
+  sqlite3JournalOpen(0, 0, pJfd, 0, -1);
+}
+
+#if defined(SQLITE_ENABLE_ATOMIC_WRITE) \
+ || defined(SQLITE_ENABLE_BATCH_ATOMIC_WRITE)
+/*
+** If the argument p points to a MemJournal structure that is not an
+** in-memory-only journal file (i.e. is one that was opened with a +ve
+** nSpill parameter or as SQLITE_OPEN_MAIN_JOURNAL), and the underlying
+** file has not yet been created, create it now.
+*/
+SQLITE_PRIVATE int sqlite3JournalCreate(sqlite3_file *pJfd){
+  int rc = SQLITE_OK;
+  MemJournal *p = (MemJournal*)pJfd;
+  if( pJfd->pMethods==&MemJournalMethods && (
+#ifdef SQLITE_ENABLE_ATOMIC_WRITE
+     p->nSpill>0
+#else
+     /* While this appears to not be possible without ATOMIC_WRITE, the
+     ** paths are complex, so it seems prudent to leave the test in as
+     ** a NEVER(), in case our analysis is subtly flawed. */
+     NEVER(p->nSpill>0)
+#endif
+#ifdef SQLITE_ENABLE_BATCH_ATOMIC_WRITE
+     || (p->flags & SQLITE_OPEN_MAIN_JOURNAL)
+#endif
+  )){
+    rc = memjrnlCreateFile(p);
+  }
+  return rc;
+}
+#endif
+
+/*
+** The file-handle passed as the only argument is open on a journal file.
+** Return true if this "journal file" is currently stored in heap memory,
+** or false otherwise.
+*/
+SQLITE_PRIVATE int sqlite3JournalIsInMemory(sqlite3_file *p){
+  return p->pMethods==&MemJournalMethods;
+}
+
+/*
+** Return the number of bytes required to store a JournalFile that uses vfs
+** pVfs to create the underlying on-disk files.
+*/
+SQLITE_PRIVATE int sqlite3JournalSize(sqlite3_vfs *pVfs){
+  return MAX(pVfs->szOsFile, (int)sizeof(MemJournal));
+}
+
+/************** End of memjournal.c ******************************************/
+/************** Begin file walker.c ******************************************/
+/*
+** 2008 August 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used for walking the parser tree for
+** an SQL statement.
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdlib.h> */
+/* #include <string.h> */
+
+
+#if !defined(SQLITE_OMIT_WINDOWFUNC)
+/*
+** Walk all expressions linked into the list of Window objects passed
+** as the second argument.
+*/
+static int walkWindowList(Walker *pWalker, Window *pList, int bOneOnly){
+  Window *pWin;
+  for(pWin=pList; pWin; pWin=pWin->pNextWin){
+    int rc;
+    rc = sqlite3WalkExprList(pWalker, pWin->pOrderBy);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExprList(pWalker, pWin->pPartition);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExpr(pWalker, pWin->pFilter);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExpr(pWalker, pWin->pStart);
+    if( rc ) return WRC_Abort;
+    rc = sqlite3WalkExpr(pWalker, pWin->pEnd);
+    if( rc ) return WRC_Abort;
+    if( bOneOnly ) break;
+  }
+  return WRC_Continue;
+}
+#endif
+
+/*
+** Walk an expression tree.  Invoke the callback once for each node
+** of the expression, while descending.  (In other words, the callback
+** is invoked before visiting children.)
+**
+** The return value from the callback should be one of the WRC_*
+** constants to specify how to proceed with the walk.
+**
+**    WRC_Continue      Continue descending down the tree.
+**
+**    WRC_Prune         Do not descend into child nodes, but allow
+**                      the walk to continue with sibling nodes.
+**
+**    WRC_Abort         Do no more callbacks.  Unwind the stack and
+**                      return from the top-level walk call.
+**
+** The return value from this routine is WRC_Abort to abandon the tree walk
+** and WRC_Continue to continue.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3WalkExprNN(Walker *pWalker, Expr *pExpr){
+  int rc;
+  testcase( ExprHasProperty(pExpr, EP_TokenOnly) );
+  testcase( ExprHasProperty(pExpr, EP_Reduced) );
+  while(1){
+    rc = pWalker->xExprCallback(pWalker, pExpr);
+    if( rc ) return rc & WRC_Abort;
+    if( !ExprHasProperty(pExpr,(EP_TokenOnly|EP_Leaf)) ){
+      assert( pExpr->x.pList==0 || pExpr->pRight==0 );
+      if( pExpr->pLeft && sqlite3WalkExprNN(pWalker, pExpr->pLeft) ){
+        return WRC_Abort;
+      }
+      if( pExpr->pRight ){
+        assert( !ExprHasProperty(pExpr, EP_WinFunc) );
+        pExpr = pExpr->pRight;
+        continue;
+      }else if( ExprUseXSelect(pExpr) ){
+        assert( !ExprHasProperty(pExpr, EP_WinFunc) );
+        if( sqlite3WalkSelect(pWalker, pExpr->x.pSelect) ) return WRC_Abort;
+      }else{
+        if( pExpr->x.pList ){
+          if( sqlite3WalkExprList(pWalker, pExpr->x.pList) ) return WRC_Abort;
+        }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        if( ExprHasProperty(pExpr, EP_WinFunc) ){
+          if( walkWindowList(pWalker, pExpr->y.pWin, 1) ) return WRC_Abort;
+        }
+#endif
+      }
+    }
+    break;
+  }
+  return WRC_Continue;
+}
+SQLITE_PRIVATE int sqlite3WalkExpr(Walker *pWalker, Expr *pExpr){
+  return pExpr ? sqlite3WalkExprNN(pWalker,pExpr) : WRC_Continue;
+}
+
+/*
+** Call sqlite3WalkExpr() for every expression in list p or until
+** an abort request is seen.
+*/
+SQLITE_PRIVATE int sqlite3WalkExprList(Walker *pWalker, ExprList *p){
+  int i;
+  struct ExprList_item *pItem;
+  if( p ){
+    for(i=p->nExpr, pItem=p->a; i>0; i--, pItem++){
+      if( sqlite3WalkExpr(pWalker, pItem->pExpr) ) return WRC_Abort;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** This is a no-op callback for Walker->xSelectCallback2.  If this
+** callback is set, then the Select->pWinDefn list is traversed.
+*/
+SQLITE_PRIVATE void sqlite3WalkWinDefnDummyCallback(Walker *pWalker, Select *p){
+  UNUSED_PARAMETER(pWalker);
+  UNUSED_PARAMETER(p);
+  /* No-op */
+}
+
+/*
+** Walk all expressions associated with SELECT statement p.  Do
+** not invoke the SELECT callback on p, but do (of course) invoke
+** any expr callbacks and SELECT callbacks that come from subqueries.
+** Return WRC_Abort or WRC_Continue.
+*/
+SQLITE_PRIVATE int sqlite3WalkSelectExpr(Walker *pWalker, Select *p){
+  if( sqlite3WalkExprList(pWalker, p->pEList) ) return WRC_Abort;
+  if( sqlite3WalkExpr(pWalker, p->pWhere) ) return WRC_Abort;
+  if( sqlite3WalkExprList(pWalker, p->pGroupBy) ) return WRC_Abort;
+  if( sqlite3WalkExpr(pWalker, p->pHaving) ) return WRC_Abort;
+  if( sqlite3WalkExprList(pWalker, p->pOrderBy) ) return WRC_Abort;
+  if( sqlite3WalkExpr(pWalker, p->pLimit) ) return WRC_Abort;
+#if !defined(SQLITE_OMIT_WINDOWFUNC)
+  if( p->pWinDefn ){
+    Parse *pParse;
+    if( pWalker->xSelectCallback2==sqlite3WalkWinDefnDummyCallback
+     || ((pParse = pWalker->pParse)!=0 && IN_RENAME_OBJECT)
+#ifndef SQLITE_OMIT_CTE
+     || pWalker->xSelectCallback2==sqlite3SelectPopWith
+#endif
+    ){
+      /* The following may return WRC_Abort if there are unresolvable
+      ** symbols (e.g. a table that does not exist) in a window definition. */
+      int rc = walkWindowList(pWalker, p->pWinDefn, 0);
+      return rc;
+    }
+  }
+#endif
+  return WRC_Continue;
+}
+
+/*
+** Walk the parse trees associated with all subqueries in the
+** FROM clause of SELECT statement p.  Do not invoke the select
+** callback on p, but do invoke it on each FROM clause subquery
+** and on any subqueries further down in the tree.  Return
+** WRC_Abort or WRC_Continue;
+*/
+SQLITE_PRIVATE int sqlite3WalkSelectFrom(Walker *pWalker, Select *p){
+  SrcList *pSrc;
+  int i;
+  SrcItem *pItem;
+
+  pSrc = p->pSrc;
+  if( ALWAYS(pSrc) ){
+    for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
+      if( pItem->fg.isSubquery
+       && sqlite3WalkSelect(pWalker, pItem->u4.pSubq->pSelect)
+      ){
+        return WRC_Abort;
+      }
+      if( pItem->fg.isTabFunc
+       && sqlite3WalkExprList(pWalker, pItem->u1.pFuncArg)
+      ){
+        return WRC_Abort;
+      }
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Call sqlite3WalkExpr() for every expression in Select statement p.
+** Invoke sqlite3WalkSelect() for subqueries in the FROM clause and
+** on the compound select chain, p->pPrior.
+**
+** If it is not NULL, the xSelectCallback() callback is invoked before
+** the walk of the expressions and FROM clause. The xSelectCallback2()
+** method is invoked following the walk of the expressions and FROM clause,
+** but only if both xSelectCallback and xSelectCallback2 are both non-NULL
+** and if the expressions and FROM clause both return WRC_Continue;
+**
+** Return WRC_Continue under normal conditions.  Return WRC_Abort if
+** there is an abort request.
+**
+** If the Walker does not have an xSelectCallback() then this routine
+** is a no-op returning WRC_Continue.
+*/
+SQLITE_PRIVATE int sqlite3WalkSelect(Walker *pWalker, Select *p){
+  int rc;
+  if( p==0 ) return WRC_Continue;
+  if( pWalker->xSelectCallback==0 ) return WRC_Continue;
+  do{
+    rc = pWalker->xSelectCallback(pWalker, p);
+    if( rc ) return rc & WRC_Abort;
+    if( sqlite3WalkSelectExpr(pWalker, p)
+     || sqlite3WalkSelectFrom(pWalker, p)
+    ){
+      return WRC_Abort;
+    }
+    if( pWalker->xSelectCallback2 ){
+      pWalker->xSelectCallback2(pWalker, p);
+    }
+    p = p->pPrior;
+  }while( p!=0 );
+  return WRC_Continue;
+}
+
+/* Increase the walkerDepth when entering a subquery, and
+** decrease when leaving the subquery.
+*/
+SQLITE_PRIVATE int sqlite3WalkerDepthIncrease(Walker *pWalker, Select *pSelect){
+  UNUSED_PARAMETER(pSelect);
+  pWalker->walkerDepth++;
+  return WRC_Continue;
+}
+SQLITE_PRIVATE void sqlite3WalkerDepthDecrease(Walker *pWalker, Select *pSelect){
+  UNUSED_PARAMETER(pSelect);
+  pWalker->walkerDepth--;
+}
+
+
+/*
+** No-op routine for the parse-tree walker.
+**
+** When this routine is the Walker.xExprCallback then expression trees
+** are walked without any actions being taken at each node.  Presumably,
+** when this routine is used for Walker.xExprCallback then
+** Walker.xSelectCallback is set to do something useful for every
+** subquery in the parser tree.
+*/
+SQLITE_PRIVATE int sqlite3ExprWalkNoop(Walker *NotUsed, Expr *NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  return WRC_Continue;
+}
+
+/*
+** No-op routine for the parse-tree walker for SELECT statements.
+** subquery in the parser tree.
+*/
+SQLITE_PRIVATE int sqlite3SelectWalkNoop(Walker *NotUsed, Select *NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  return WRC_Continue;
+}
+
+/************** End of walker.c **********************************************/
+/************** Begin file resolve.c *****************************************/
+/*
+** 2008 August 18
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains routines used for walking the parser tree and
+** resolve all identifiers by associating them with a particular
+** table and column.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** Magic table number to mean the EXCLUDED table in an UPSERT statement.
+*/
+#define EXCLUDED_TABLE_NUMBER  2
+
+/*
+** Walk the expression tree pExpr and increase the aggregate function
+** depth (the Expr.op2 field) by N on every TK_AGG_FUNCTION node.
+** This needs to occur when copying a TK_AGG_FUNCTION node from an
+** outer query into an inner subquery.
+**
+** incrAggFunctionDepth(pExpr,n) is the main routine.  incrAggDepth(..)
+** is a helper function - a callback for the tree walker.
+**
+** See also the sqlite3WindowExtraAggFuncDepth() routine in window.c
+*/
+static int incrAggDepth(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_AGG_FUNCTION ) pExpr->op2 += pWalker->u.n;
+  return WRC_Continue;
+}
+static void incrAggFunctionDepth(Expr *pExpr, int N){
+  if( N>0 ){
+    Walker w;
+    memset(&w, 0, sizeof(w));
+    w.xExprCallback = incrAggDepth;
+    w.u.n = N;
+    sqlite3WalkExpr(&w, pExpr);
+  }
+}
+
+/*
+** Turn the pExpr expression into an alias for the iCol-th column of the
+** result set in pEList.
+**
+** If the reference is followed by a COLLATE operator, then make sure
+** the COLLATE operator is preserved.  For example:
+**
+**     SELECT a+b, c+d FROM t1 ORDER BY 1 COLLATE nocase;
+**
+** Should be transformed into:
+**
+**     SELECT a+b, c+d FROM t1 ORDER BY (a+b) COLLATE nocase;
+**
+** The nSubquery parameter specifies how many levels of subquery the
+** alias is removed from the original expression.  The usual value is
+** zero but it might be more if the alias is contained within a subquery
+** of the original expression.  The Expr.op2 field of TK_AGG_FUNCTION
+** structures must be increased by the nSubquery amount.
+*/
+static void resolveAlias(
+  Parse *pParse,         /* Parsing context */
+  ExprList *pEList,      /* A result set */
+  int iCol,              /* A column in the result set.  0..pEList->nExpr-1 */
+  Expr *pExpr,           /* Transform this into an alias to the result set */
+  int nSubquery          /* Number of subqueries that the label is moving */
+){
+  Expr *pOrig;           /* The iCol-th column of the result set */
+  Expr *pDup;            /* Copy of pOrig */
+  sqlite3 *db;           /* The database connection */
+
+  assert( iCol>=0 && iCol<pEList->nExpr );
+  pOrig = pEList->a[iCol].pExpr;
+  assert( pOrig!=0 );
+  assert( !ExprHasProperty(pExpr, EP_Reduced|EP_TokenOnly) );
+  if( pExpr->pAggInfo ) return;
+  db = pParse->db;
+  pDup = sqlite3ExprDup(db, pOrig, 0);
+  if( db->mallocFailed ){
+    sqlite3ExprDelete(db, pDup);
+    pDup = 0;
+  }else{
+    Expr temp;
+    incrAggFunctionDepth(pDup, nSubquery);
+    if( pExpr->op==TK_COLLATE ){
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      pDup = sqlite3ExprAddCollateString(pParse, pDup, pExpr->u.zToken);
+    }
+    memcpy(&temp, pDup, sizeof(Expr));
+    memcpy(pDup, pExpr, sizeof(Expr));
+    memcpy(pExpr, &temp, sizeof(Expr));
+    if( ExprHasProperty(pExpr, EP_WinFunc) ){
+      if( ALWAYS(pExpr->y.pWin!=0) ){
+        pExpr->y.pWin->pOwner = pExpr;
+      }
+    }
+    sqlite3ExprDeferredDelete(pParse, pDup);
+  }
+}
+
+/*
+** Subqueries store the original database, table and column names for their
+** result sets in ExprList.a[].zSpan, in the form "DATABASE.TABLE.COLUMN",
+** and mark the expression-list item by setting ExprList.a[].fg.eEName
+** to ENAME_TAB.
+**
+** Check to see if the zSpan/eEName of the expression-list item passed to this
+** routine matches the zDb, zTab, and zCol.  If any of zDb, zTab, and zCol are
+** NULL then those fields will match anything. Return true if there is a match,
+** or false otherwise.
+**
+** SF_NestedFrom subqueries also store an entry for the implicit rowid (or
+** _rowid_, or oid) column by setting ExprList.a[].fg.eEName to ENAME_ROWID,
+** and setting zSpan to "DATABASE.TABLE.<rowid-alias>". This type of pItem
+** argument matches if zCol is a rowid alias. If it is not NULL, (*pbRowid)
+** is set to 1 if there is this kind of match.
+*/
+SQLITE_PRIVATE int sqlite3MatchEName(
+  const struct ExprList_item *pItem,
+  const char *zCol,
+  const char *zTab,
+  const char *zDb,
+  int *pbRowid
+){
+  int n;
+  const char *zSpan;
+  int eEName = pItem->fg.eEName;
+  if( eEName!=ENAME_TAB && (eEName!=ENAME_ROWID || NEVER(pbRowid==0)) ){
+    return 0;
+  }
+  assert( pbRowid==0 || *pbRowid==0 );
+  zSpan = pItem->zEName;
+  for(n=0; ALWAYS(zSpan[n]) && zSpan[n]!='.'; n++){}
+  if( zDb && (sqlite3StrNICmp(zSpan, zDb, n)!=0 || zDb[n]!=0) ){
+    return 0;
+  }
+  zSpan += n+1;
+  for(n=0; ALWAYS(zSpan[n]) && zSpan[n]!='.'; n++){}
+  if( zTab && (sqlite3StrNICmp(zSpan, zTab, n)!=0 || zTab[n]!=0) ){
+    return 0;
+  }
+  zSpan += n+1;
+  if( zCol ){
+    if( eEName==ENAME_TAB && sqlite3StrICmp(zSpan, zCol)!=0 ) return 0;
+    if( eEName==ENAME_ROWID && sqlite3IsRowid(zCol)==0 ) return 0;
+  }
+  if( eEName==ENAME_ROWID ) *pbRowid = 1;
+  return 1;
+}
+
+/*
+** Return TRUE if the double-quoted string  mis-feature should be supported.
+*/
+static int areDoubleQuotedStringsEnabled(sqlite3 *db, NameContext *pTopNC){
+  if( db->init.busy ) return 1;  /* Always support for legacy schemas */
+  if( pTopNC->ncFlags & NC_IsDDL ){
+    /* Currently parsing a DDL statement */
+    if( sqlite3WritableSchema(db) && (db->flags & SQLITE_DqsDML)!=0 ){
+      return 1;
+    }
+    return (db->flags & SQLITE_DqsDDL)!=0;
+  }else{
+    /* Currently parsing a DML statement */
+    return (db->flags & SQLITE_DqsDML)!=0;
+  }
+}
+
+/*
+** The argument is guaranteed to be a non-NULL Expr node of type TK_COLUMN.
+** return the appropriate colUsed mask.
+*/
+SQLITE_PRIVATE Bitmask sqlite3ExprColUsed(Expr *pExpr){
+  int n;
+  Table *pExTab;
+
+  n = pExpr->iColumn;
+  assert( ExprUseYTab(pExpr) );
+  pExTab = pExpr->y.pTab;
+  assert( pExTab!=0 );
+  assert( n < pExTab->nCol );
+  if( (pExTab->tabFlags & TF_HasGenerated)!=0
+   && (pExTab->aCol[n].colFlags & COLFLAG_GENERATED)!=0
+  ){
+    testcase( pExTab->nCol==BMS-1 );
+    testcase( pExTab->nCol==BMS );
+    return pExTab->nCol>=BMS ? ALLBITS : MASKBIT(pExTab->nCol)-1;
+  }else{
+    testcase( n==BMS-1 );
+    testcase( n==BMS );
+    if( n>=BMS ) n = BMS-1;
+    return ((Bitmask)1)<<n;
+  }
+}
+
+/*
+** Create a new expression term for the column specified by pMatch and
+** iColumn.  Append this new expression term to the FULL JOIN Match set
+** in *ppList.  Create a new *ppList if this is the first term in the
+** set.
+*/
+static void extendFJMatch(
+  Parse *pParse,          /* Parsing context */
+  ExprList **ppList,      /* ExprList to extend */
+  SrcItem *pMatch,        /* Source table containing the column */
+  i16 iColumn             /* The column number */
+){
+  Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0);
+  if( pNew ){
+    pNew->iTable = pMatch->iCursor;
+    pNew->iColumn = iColumn;
+    pNew->y.pTab = pMatch->pSTab;
+    assert( (pMatch->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 );
+    ExprSetProperty(pNew, EP_CanBeNull);
+    *ppList = sqlite3ExprListAppend(pParse, *ppList, pNew);
+  }
+}
+
+/*
+** Return TRUE (non-zero) if zTab is a valid name for the schema table pTab.
+*/
+static SQLITE_NOINLINE int isValidSchemaTableName(
+  const char *zTab,         /* Name as it appears in the SQL */
+  Table *pTab,              /* The schema table we are trying to match */
+  const char *zDb           /* non-NULL if a database qualifier is present */
+){
+  const char *zLegacy;
+  assert( pTab!=0 );
+  assert( pTab->tnum==1 );
+  if( sqlite3StrNICmp(zTab, "sqlite_", 7)!=0 ) return 0;
+  zLegacy = pTab->zName;
+  if( strcmp(zLegacy+7, &LEGACY_TEMP_SCHEMA_TABLE[7])==0 ){
+    if( sqlite3StrICmp(zTab+7, &PREFERRED_TEMP_SCHEMA_TABLE[7])==0 ){
+      return 1;
+    }
+    if( zDb==0 ) return 0;
+    if( sqlite3StrICmp(zTab+7, &LEGACY_SCHEMA_TABLE[7])==0 ) return 1;
+    if( sqlite3StrICmp(zTab+7, &PREFERRED_SCHEMA_TABLE[7])==0 ) return 1;
+  }else{
+    if( sqlite3StrICmp(zTab+7, &PREFERRED_SCHEMA_TABLE[7])==0 ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
+** that name in the set of source tables in pSrcList and make the pExpr
+** expression node refer back to that source column.  The following changes
+** are made to pExpr:
+**
+**    pExpr->iDb           Set the index in db->aDb[] of the database X
+**                         (even if X is implied).
+**    pExpr->iTable        Set to the cursor number for the table obtained
+**                         from pSrcList.
+**    pExpr->y.pTab        Points to the Table structure of X.Y (even if
+**                         X and/or Y are implied.)
+**    pExpr->iColumn       Set to the column number within the table.
+**    pExpr->op            Set to TK_COLUMN.
+**    pExpr->pLeft         Any expression this points to is deleted
+**    pExpr->pRight        Any expression this points to is deleted.
+**
+** The zDb variable is the name of the database (the "X").  This value may be
+** NULL meaning that name is of the form Y.Z or Z.  Any available database
+** can be used.  The zTable variable is the name of the table (the "Y").  This
+** value can be NULL if zDb is also NULL.  If zTable is NULL it
+** means that the form of the name is Z and that columns from any table
+** can be used.
+**
+** If the name cannot be resolved unambiguously, leave an error message
+** in pParse and return WRC_Abort.  Return WRC_Prune on success.
+*/
+static int lookupName(
+  Parse *pParse,       /* The parsing context */
+  const char *zDb,     /* Name of the database containing table, or NULL */
+  const char *zTab,    /* Name of table containing column, or NULL */
+  const Expr *pRight,  /* Name of the column. */
+  NameContext *pNC,    /* The name context used to resolve the name */
+  Expr *pExpr          /* Make this EXPR node point to the selected column */
+){
+  int i, j;                         /* Loop counters */
+  int cnt = 0;                      /* Number of matching column names */
+  int cntTab = 0;                   /* Number of potential "rowid" matches */
+  int nSubquery = 0;                /* How many levels of subquery */
+  sqlite3 *db = pParse->db;         /* The database connection */
+  SrcItem *pItem;                   /* Use for looping over pSrcList items */
+  SrcItem *pMatch = 0;              /* The matching pSrcList item */
+  NameContext *pTopNC = pNC;        /* First namecontext in the list */
+  Schema *pSchema = 0;              /* Schema of the expression */
+  int eNewExprOp = TK_COLUMN;       /* New value for pExpr->op on success */
+  Table *pTab = 0;                  /* Table holding the row */
+  Column *pCol;                     /* A column of pTab */
+  ExprList *pFJMatch = 0;           /* Matches for FULL JOIN .. USING */
+  const char *zCol = pRight->u.zToken;
+
+  assert( pNC );     /* the name context cannot be NULL. */
+  assert( zCol );    /* The Z in X.Y.Z cannot be NULL */
+  assert( zDb==0 || zTab!=0 );
+  assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+
+  /* Initialize the node to no-match */
+  pExpr->iTable = -1;
+  ExprSetVVAProperty(pExpr, EP_NoReduce);
+
+  /* Translate the schema name in zDb into a pointer to the corresponding
+  ** schema.  If not found, pSchema will remain NULL and nothing will match
+  ** resulting in an appropriate error message toward the end of this routine
+  */
+  if( zDb ){
+    testcase( pNC->ncFlags & NC_PartIdx );
+    testcase( pNC->ncFlags & NC_IsCheck );
+    if( (pNC->ncFlags & (NC_PartIdx|NC_IsCheck))!=0 ){
+      /* Silently ignore database qualifiers inside CHECK constraints and
+      ** partial indices.  Do not raise errors because that might break
+      ** legacy and because it does not hurt anything to just ignore the
+      ** database name. */
+      zDb = 0;
+    }else{
+      for(i=0; i<db->nDb; i++){
+        assert( db->aDb[i].zDbSName );
+        if( sqlite3StrICmp(db->aDb[i].zDbSName,zDb)==0 ){
+          pSchema = db->aDb[i].pSchema;
+          break;
+        }
+      }
+      if( i==db->nDb && sqlite3StrICmp("main", zDb)==0 ){
+        /* This branch is taken when the main database has been renamed
+        ** using SQLITE_DBCONFIG_MAINDBNAME. */
+        pSchema = db->aDb[0].pSchema;
+        zDb = db->aDb[0].zDbSName;
+      }
+    }
+  }
+
+  /* Start at the inner-most context and move outward until a match is found */
+  assert( pNC && cnt==0 );
+  do{
+    ExprList *pEList;
+    SrcList *pSrcList = pNC->pSrcList;
+
+    if( pSrcList ){
+      for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
+        u8 hCol;
+        pTab = pItem->pSTab;
+        assert( pTab!=0 && pTab->zName!=0 );
+        assert( pTab->nCol>0 || pParse->nErr );
+        assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem));
+        if( pItem->fg.isNestedFrom ){
+          /* In this case, pItem is a subquery that has been formed from a
+          ** parenthesized subset of the FROM clause terms.  Example:
+          **   .... FROM t1 LEFT JOIN (t2 RIGHT JOIN t3 USING(x)) USING(y) ...
+          **                          \_________________________/
+          **             This pItem -------------^
+          */
+          int hit = 0;
+          Select *pSel;
+          assert( pItem->fg.isSubquery );
+          assert( pItem->u4.pSubq!=0 );
+          pSel = pItem->u4.pSubq->pSelect;
+          assert( pSel!=0 );
+          pEList = pSel->pEList;
+          assert( pEList!=0 );
+          assert( pEList->nExpr==pTab->nCol );
+          for(j=0; j<pEList->nExpr; j++){
+            int bRowid = 0;       /* True if possible rowid match */
+            if( !sqlite3MatchEName(&pEList->a[j], zCol, zTab, zDb, &bRowid) ){
+              continue;
+            }
+            if( bRowid==0 ){
+              if( cnt>0 ){
+                if( pItem->fg.isUsing==0
+                 || sqlite3IdListIndex(pItem->u3.pUsing, zCol)<0
+                ){
+                  /* Two or more tables have the same column name which is
+                  ** not joined by USING.  This is an error.  Signal as much
+                  ** by clearing pFJMatch and letting cnt go above 1. */
+                  sqlite3ExprListDelete(db, pFJMatch);
+                  pFJMatch = 0;
+                }else
+                if( (pItem->fg.jointype & JT_RIGHT)==0 ){
+                  /* An INNER or LEFT JOIN.  Use the left-most table */
+                  continue;
+                }else
+                if( (pItem->fg.jointype & JT_LEFT)==0 ){
+                  /* A RIGHT JOIN.  Use the right-most table */
+                  cnt = 0;
+                  sqlite3ExprListDelete(db, pFJMatch);
+                  pFJMatch = 0;
+                }else{
+                  /* For a FULL JOIN, we must construct a coalesce() func */
+                  extendFJMatch(pParse, &pFJMatch, pMatch, pExpr->iColumn);
+                }
+              }
+              cnt++;
+              hit = 1;
+            }else if( cnt>0 ){
+              /* This is a potential rowid match, but there has already been
+              ** a real match found. So this can be ignored.  */
+              continue;
+            }
+            cntTab++;
+            pMatch = pItem;
+            pExpr->iColumn = j;
+            pEList->a[j].fg.bUsed = 1;
+
+            /* rowid cannot be part of a USING clause - assert() this. */
+            assert( bRowid==0 || pEList->a[j].fg.bUsingTerm==0 );
+            if( pEList->a[j].fg.bUsingTerm ) break;
+          }
+          if( hit || zTab==0 ) continue;
+        }
+        assert( zDb==0 || zTab!=0 );
+        if( zTab ){
+          if( zDb ){
+            if( pTab->pSchema!=pSchema ) continue;
+            if( pSchema==0 && strcmp(zDb,"*")!=0 ) continue;
+          }
+          if( pItem->zAlias!=0 ){
+            if( sqlite3StrICmp(zTab, pItem->zAlias)!=0 ){
+              continue;
+            }
+          }else if( sqlite3StrICmp(zTab, pTab->zName)!=0 ){
+            if( pTab->tnum!=1 ) continue;
+            if( !isValidSchemaTableName(zTab, pTab, zDb) ) continue;
+          }
+          assert( ExprUseYTab(pExpr) );
+          if( IN_RENAME_OBJECT && pItem->zAlias ){
+            sqlite3RenameTokenRemap(pParse, 0, (void*)&pExpr->y.pTab);
+          }
+        }
+        hCol = sqlite3StrIHash(zCol);
+        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
+          if( pCol->hName==hCol
+           && sqlite3StrICmp(pCol->zCnName, zCol)==0
+          ){
+            if( cnt>0 ){
+              if( pItem->fg.isUsing==0
+               || sqlite3IdListIndex(pItem->u3.pUsing, zCol)<0
+              ){
+                /* Two or more tables have the same column name which is
+                ** not joined by USING.  This is an error.  Signal as much
+                ** by clearing pFJMatch and letting cnt go above 1. */
+                sqlite3ExprListDelete(db, pFJMatch);
+                pFJMatch = 0;
+              }else
+              if( (pItem->fg.jointype & JT_RIGHT)==0 ){
+                /* An INNER or LEFT JOIN.  Use the left-most table */
+                continue;
+              }else
+              if( (pItem->fg.jointype & JT_LEFT)==0 ){
+                /* A RIGHT JOIN.  Use the right-most table */
+                cnt = 0;
+                sqlite3ExprListDelete(db, pFJMatch);
+                pFJMatch = 0;
+              }else{
+                /* For a FULL JOIN, we must construct a coalesce() func */
+                extendFJMatch(pParse, &pFJMatch, pMatch, pExpr->iColumn);
+              }
+            }
+            cnt++;
+            pMatch = pItem;
+            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
+            pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
+            if( pItem->fg.isNestedFrom ){
+              sqlite3SrcItemColumnUsed(pItem, j);
+            }
+            break;
+          }
+        }
+        if( 0==cnt && VisibleRowid(pTab) ){
+          /* pTab is a potential ROWID match.  Keep track of it and match
+          ** the ROWID later if that seems appropriate.  (Search for "cntTab"
+          ** to find related code.)  Only allow a ROWID match if there is
+          ** a single ROWID match candidate.
+          */
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+          /* In SQLITE_ALLOW_ROWID_IN_VIEW mode, allow a ROWID match
+          ** if there is a single VIEW candidate or if there is a single
+          ** non-VIEW candidate plus multiple VIEW candidates.  In other
+          ** words non-VIEW candidate terms take precedence over VIEWs.
+          */
+          if( cntTab==0
+           || (cntTab==1
+               && pMatch!=0
+               && ALWAYS(pMatch->pSTab!=0)
+               && (pMatch->pSTab->tabFlags & TF_Ephemeral)!=0
+               && (pTab->tabFlags & TF_Ephemeral)==0)
+          ){
+            cntTab = 1;
+            pMatch = pItem;
+          }else{
+            cntTab++;
+          }
+#else
+          /* The (much more common) non-SQLITE_ALLOW_ROWID_IN_VIEW case is
+          ** simpler since we require exactly one candidate, which will
+          ** always be a non-VIEW
+          */
+          cntTab++;
+          pMatch = pItem;
+#endif
+        }
+      }
+      if( pMatch ){
+        pExpr->iTable = pMatch->iCursor;
+        assert( ExprUseYTab(pExpr) );
+        pExpr->y.pTab = pMatch->pSTab;
+        if( (pMatch->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 ){
+          ExprSetProperty(pExpr, EP_CanBeNull);
+        }
+        pSchema = pExpr->y.pTab->pSchema;
+      }
+    } /* if( pSrcList ) */
+
+#if !defined(SQLITE_OMIT_TRIGGER) || !defined(SQLITE_OMIT_UPSERT)
+    /* If we have not already resolved the name, then maybe
+    ** it is a new.* or old.* trigger argument reference.  Or
+    ** maybe it is an excluded.* from an upsert.  Or maybe it is
+    ** a reference in the RETURNING clause to a table being modified.
+    */
+    if( cnt==0 && zDb==0 ){
+      pTab = 0;
+#ifndef SQLITE_OMIT_TRIGGER
+      if( pParse->pTriggerTab!=0 ){
+        int op = pParse->eTriggerOp;
+        assert( op==TK_DELETE || op==TK_UPDATE || op==TK_INSERT );
+        if( pParse->bReturning ){
+          if( (pNC->ncFlags & NC_UBaseReg)!=0
+           && ALWAYS(zTab==0
+                     || sqlite3StrICmp(zTab,pParse->pTriggerTab->zName)==0
+                     || isValidSchemaTableName(zTab, pParse->pTriggerTab, 0))
+          ){
+            pExpr->iTable = op!=TK_DELETE;
+            pTab = pParse->pTriggerTab;
+          }
+        }else if( op!=TK_DELETE && zTab && sqlite3StrICmp("new",zTab) == 0 ){
+          pExpr->iTable = 1;
+          pTab = pParse->pTriggerTab;
+        }else if( op!=TK_INSERT && zTab && sqlite3StrICmp("old",zTab)==0 ){
+          pExpr->iTable = 0;
+          pTab = pParse->pTriggerTab;
+        }
+      }
+#endif /* SQLITE_OMIT_TRIGGER */
+#ifndef SQLITE_OMIT_UPSERT
+      if( (pNC->ncFlags & NC_UUpsert)!=0 && zTab!=0 ){
+        Upsert *pUpsert = pNC->uNC.pUpsert;
+        if( pUpsert && sqlite3StrICmp("excluded",zTab)==0 ){
+          pTab = pUpsert->pUpsertSrc->a[0].pSTab;
+          pExpr->iTable = EXCLUDED_TABLE_NUMBER;
+        }
+      }
+#endif /* SQLITE_OMIT_UPSERT */
+
+      if( pTab ){
+        int iCol;
+        u8 hCol = sqlite3StrIHash(zCol);
+        pSchema = pTab->pSchema;
+        cntTab++;
+        for(iCol=0, pCol=pTab->aCol; iCol<pTab->nCol; iCol++, pCol++){
+          if( pCol->hName==hCol
+           && sqlite3StrICmp(pCol->zCnName, zCol)==0
+          ){
+            if( iCol==pTab->iPKey ){
+              iCol = -1;
+            }
+            break;
+          }
+        }
+        if( iCol>=pTab->nCol && sqlite3IsRowid(zCol) && VisibleRowid(pTab) ){
+          /* IMP: R-51414-32910 */
+          iCol = -1;
+        }
+        if( iCol<pTab->nCol ){
+          cnt++;
+          pMatch = 0;
+#ifndef SQLITE_OMIT_UPSERT
+          if( pExpr->iTable==EXCLUDED_TABLE_NUMBER ){
+            testcase( iCol==(-1) );
+            assert( ExprUseYTab(pExpr) );
+            if( IN_RENAME_OBJECT ){
+              pExpr->iColumn = iCol;
+              pExpr->y.pTab = pTab;
+              eNewExprOp = TK_COLUMN;
+            }else{
+              pExpr->iTable = pNC->uNC.pUpsert->regData +
+                 sqlite3TableColumnToStorage(pTab, iCol);
+              eNewExprOp = TK_REGISTER;
+            }
+          }else
+#endif /* SQLITE_OMIT_UPSERT */
+          {
+            assert( ExprUseYTab(pExpr) );
+            pExpr->y.pTab = pTab;
+            if( pParse->bReturning ){
+              eNewExprOp = TK_REGISTER;
+              pExpr->op2 = TK_COLUMN;
+              pExpr->iColumn = iCol;
+              pExpr->iTable = pNC->uNC.iBaseReg + (pTab->nCol+1)*pExpr->iTable +
+                 sqlite3TableColumnToStorage(pTab, iCol) + 1;
+            }else{
+              pExpr->iColumn = (i16)iCol;
+              eNewExprOp = TK_TRIGGER;
+#ifndef SQLITE_OMIT_TRIGGER
+              if( iCol<0 ){
+                pExpr->affExpr = SQLITE_AFF_INTEGER;
+              }else if( pExpr->iTable==0 ){
+                testcase( iCol==31 );
+                testcase( iCol==32 );
+                pParse->oldmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
+              }else{
+                testcase( iCol==31 );
+                testcase( iCol==32 );
+                pParse->newmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
+              }
+#endif /* SQLITE_OMIT_TRIGGER */
+            }
+          }
+        }
+      }
+    }
+#endif /* !defined(SQLITE_OMIT_TRIGGER) || !defined(SQLITE_OMIT_UPSERT) */
+
+    /*
+    ** Perhaps the name is a reference to the ROWID
+    */
+    if( cnt==0
+     && cntTab>=1
+     && pMatch
+     && (pNC->ncFlags & (NC_IdxExpr|NC_GenCol))==0
+     && sqlite3IsRowid(zCol)
+     && ALWAYS(VisibleRowid(pMatch->pSTab) || pMatch->fg.isNestedFrom)
+    ){
+      cnt = cntTab;
+#if SQLITE_ALLOW_ROWID_IN_VIEW+0==2
+      if( pMatch->pSTab!=0 && IsView(pMatch->pSTab) ){
+        eNewExprOp = TK_NULL;
+      }
+#endif
+      if( pMatch->fg.isNestedFrom==0 ) pExpr->iColumn = -1;
+      pExpr->affExpr = SQLITE_AFF_INTEGER;
+    }
+
+    /*
+    ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
+    ** might refer to an result-set alias.  This happens, for example, when
+    ** we are resolving names in the WHERE clause of the following command:
+    **
+    **     SELECT a+b AS x FROM table WHERE x<10;
+    **
+    ** In cases like this, replace pExpr with a copy of the expression that
+    ** forms the result set entry ("a+b" in the example) and return immediately.
+    ** Note that the expression in the result set should have already been
+    ** resolved by the time the WHERE clause is resolved.
+    **
+    ** The ability to use an output result-set column in the WHERE, GROUP BY,
+    ** or HAVING clauses, or as part of a larger expression in the ORDER BY
+    ** clause is not standard SQL.  This is a (goofy) SQLite extension, that
+    ** is supported for backwards compatibility only. Hence, we issue a warning
+    ** on sqlite3_log() whenever the capability is used.
+    */
+    if( cnt==0
+     && (pNC->ncFlags & NC_UEList)!=0
+     && zTab==0
+    ){
+      pEList = pNC->uNC.pEList;
+      assert( pEList!=0 );
+      for(j=0; j<pEList->nExpr; j++){
+        char *zAs = pEList->a[j].zEName;
+        if( pEList->a[j].fg.eEName==ENAME_NAME
+         && sqlite3_stricmp(zAs, zCol)==0
+        ){
+          Expr *pOrig;
+          assert( pExpr->pLeft==0 && pExpr->pRight==0 );
+          assert( ExprUseXList(pExpr)==0 || pExpr->x.pList==0 );
+          assert( ExprUseXSelect(pExpr)==0 || pExpr->x.pSelect==0 );
+          pOrig = pEList->a[j].pExpr;
+          if( (pNC->ncFlags&NC_AllowAgg)==0 && ExprHasProperty(pOrig, EP_Agg) ){
+            sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
+            return WRC_Abort;
+          }
+          if( ExprHasProperty(pOrig, EP_Win)
+           && ((pNC->ncFlags&NC_AllowWin)==0 || pNC!=pTopNC )
+          ){
+            sqlite3ErrorMsg(pParse, "misuse of aliased window function %s",zAs);
+            return WRC_Abort;
+          }
+          if( sqlite3ExprVectorSize(pOrig)!=1 ){
+            sqlite3ErrorMsg(pParse, "row value misused");
+            return WRC_Abort;
+          }
+          resolveAlias(pParse, pEList, j, pExpr, nSubquery);
+          cnt = 1;
+          pMatch = 0;
+          assert( zTab==0 && zDb==0 );
+          if( IN_RENAME_OBJECT ){
+            sqlite3RenameTokenRemap(pParse, 0, (void*)pExpr);
+          }
+          goto lookupname_end;
+        }
+      }
+    }
+
+    /* Advance to the next name context.  The loop will exit when either
+    ** we have a match (cnt>0) or when we run out of name contexts.
+    */
+    if( cnt ) break;
+    pNC = pNC->pNext;
+    nSubquery++;
+  }while( pNC );
+
+
+  /*
+  ** If X and Y are NULL (in other words if only the column name Z is
+  ** supplied) and the value of Z is enclosed in double-quotes, then
+  ** Z is a string literal if it doesn't match any column names.  In that
+  ** case, we need to return right away and not make any changes to
+  ** pExpr.
+  **
+  ** Because no reference was made to outer contexts, the pNC->nRef
+  ** fields are not changed in any context.
+  */
+  if( cnt==0 && zTab==0 ){
+    assert( pExpr->op==TK_ID );
+    if( ExprHasProperty(pExpr,EP_DblQuoted)
+     && areDoubleQuotedStringsEnabled(db, pTopNC)
+    ){
+      /* If a double-quoted identifier does not match any known column name,
+      ** then treat it as a string.
+      **
+      ** This hack was added in the early days of SQLite in a misguided attempt
+      ** to be compatible with MySQL 3.x, which used double-quotes for strings.
+      ** I now sorely regret putting in this hack. The effect of this hack is
+      ** that misspelled identifier names are silently converted into strings
+      ** rather than causing an error, to the frustration of countless
+      ** programmers. To all those frustrated programmers, my apologies.
+      **
+      ** Someday, I hope to get rid of this hack. Unfortunately there is
+      ** a huge amount of legacy SQL that uses it. So for now, we just
+      ** issue a warning.
+      */
+      sqlite3_log(SQLITE_WARNING,
+        "double-quoted string literal: \"%w\"", zCol);
+#ifdef SQLITE_ENABLE_NORMALIZE
+      sqlite3VdbeAddDblquoteStr(db, pParse->pVdbe, zCol);
+#endif
+      pExpr->op = TK_STRING;
+      memset(&pExpr->y, 0, sizeof(pExpr->y));
+      return WRC_Prune;
+    }
+    if( sqlite3ExprIdToTrueFalse(pExpr) ){
+      return WRC_Prune;
+    }
+  }
+
+  /*
+  ** cnt==0 means there was not match.
+  ** cnt>1 means there were two or more matches.
+  **
+  ** cnt==0 is always an error.  cnt>1 is often an error, but might
+  ** be multiple matches for a NATURAL LEFT JOIN or a LEFT JOIN USING.
+  */
+  assert( pFJMatch==0 || cnt>0 );
+  assert( !ExprHasProperty(pExpr, EP_xIsSelect|EP_IntValue) );
+  if( cnt!=1 ){
+    const char *zErr;
+    if( pFJMatch ){
+      if( pFJMatch->nExpr==cnt-1 ){
+        if( ExprHasProperty(pExpr,EP_Leaf) ){
+          ExprClearProperty(pExpr,EP_Leaf);
+        }else{
+          sqlite3ExprDelete(db, pExpr->pLeft);
+          pExpr->pLeft = 0;
+          sqlite3ExprDelete(db, pExpr->pRight);
+          pExpr->pRight = 0;
+        }
+        extendFJMatch(pParse, &pFJMatch, pMatch, pExpr->iColumn);
+        pExpr->op = TK_FUNCTION;
+        pExpr->u.zToken = "coalesce";
+        pExpr->x.pList = pFJMatch;
+        cnt = 1;
+        goto lookupname_end;
+      }else{
+        sqlite3ExprListDelete(db, pFJMatch);
+        pFJMatch = 0;
+      }
+    }
+    zErr = cnt==0 ? "no such column" : "ambiguous column name";
+    if( zDb ){
+      sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol);
+    }else if( zTab ){
+      sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol);
+    }else if( cnt==0 && ExprHasProperty(pRight,EP_DblQuoted) ){
+      sqlite3ErrorMsg(pParse, "%s: \"%s\" - should this be a"
+                              " string literal in single-quotes?",
+                              zErr, zCol);
+    }else{
+      sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
+    }
+    sqlite3RecordErrorOffsetOfExpr(pParse->db, pExpr);
+    pParse->checkSchema = 1;
+    pTopNC->nNcErr++;
+    eNewExprOp = TK_NULL;
+  }
+  assert( pFJMatch==0 );
+
+  /* Remove all substructure from pExpr */
+  if( !ExprHasProperty(pExpr,(EP_TokenOnly|EP_Leaf)) ){
+    sqlite3ExprDelete(db, pExpr->pLeft);
+    pExpr->pLeft = 0;
+    sqlite3ExprDelete(db, pExpr->pRight);
+    pExpr->pRight = 0;
+    ExprSetProperty(pExpr, EP_Leaf);
+  }
+
+  /* If a column from a table in pSrcList is referenced, then record
+  ** this fact in the pSrcList.a[].colUsed bitmask.  Column 0 causes
+  ** bit 0 to be set.  Column 1 sets bit 1.  And so forth.  Bit 63 is
+  ** set if the 63rd or any subsequent column is used.
+  **
+  ** The colUsed mask is an optimization used to help determine if an
+  ** index is a covering index.  The correct answer is still obtained
+  ** if the mask contains extra set bits.  However, it is important to
+  ** avoid setting bits beyond the maximum column number of the table.
+  ** (See ticket [b92e5e8ec2cdbaa1]).
+  **
+  ** If a generated column is referenced, set bits for every column
+  ** of the table.
+  */
+  if( pMatch ){
+    if( pExpr->iColumn>=0 ){
+      pMatch->colUsed |= sqlite3ExprColUsed(pExpr);
+    }else{
+      pMatch->fg.rowidUsed = 1;
+    }
+  }
+
+  pExpr->op = eNewExprOp;
+lookupname_end:
+  if( cnt==1 ){
+    assert( pNC!=0 );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    if( pParse->db->xAuth
+     && (pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER)
+    ){
+      sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
+    }
+#endif
+    /* Increment the nRef value on all name contexts from TopNC up to
+    ** the point where the name matched. */
+    for(;;){
+      assert( pTopNC!=0 );
+      pTopNC->nRef++;
+      if( pTopNC==pNC ) break;
+      pTopNC = pTopNC->pNext;
+    }
+    return WRC_Prune;
+  } else {
+    return WRC_Abort;
+  }
+}
+
+/*
+** Allocate and return a pointer to an expression to load the column iCol
+** from datasource iSrc in SrcList pSrc.
+*/
+SQLITE_PRIVATE Expr *sqlite3CreateColumnExpr(sqlite3 *db, SrcList *pSrc, int iSrc, int iCol){
+  Expr *p = sqlite3ExprAlloc(db, TK_COLUMN, 0, 0);
+  if( p ){
+    SrcItem *pItem = &pSrc->a[iSrc];
+    Table *pTab;
+    assert( ExprUseYTab(p) );
+    pTab = p->y.pTab = pItem->pSTab;
+    p->iTable = pItem->iCursor;
+    if( p->y.pTab->iPKey==iCol ){
+      p->iColumn = -1;
+    }else{
+      p->iColumn = (ynVar)iCol;
+      if( (pTab->tabFlags & TF_HasGenerated)!=0
+       && (pTab->aCol[iCol].colFlags & COLFLAG_GENERATED)!=0
+      ){
+        testcase( pTab->nCol==63 );
+        testcase( pTab->nCol==64 );
+        pItem->colUsed = pTab->nCol>=64 ? ALLBITS : MASKBIT(pTab->nCol)-1;
+      }else{
+        testcase( iCol==BMS );
+        testcase( iCol==BMS-1 );
+        pItem->colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol);
+      }
+    }
+  }
+  return p;
+}
+
+/*
+** Report an error that an expression is not valid for some set of
+** pNC->ncFlags values determined by validMask.
+**
+** static void notValid(
+**   Parse *pParse,       // Leave error message here
+**   NameContext *pNC,    // The name context
+**   const char *zMsg,    // Type of error
+**   int validMask,       // Set of contexts for which prohibited
+**   Expr *pExpr          // Invalidate this expression on error
+** ){...}
+**
+** As an optimization, since the conditional is almost always false
+** (because errors are rare), the conditional is moved outside of the
+** function call using a macro.
+*/
+static void notValidImpl(
+   Parse *pParse,       /* Leave error message here */
+   NameContext *pNC,    /* The name context */
+   const char *zMsg,    /* Type of error */
+   Expr *pExpr,         /* Invalidate this expression on error */
+   Expr *pError         /* Associate error with this expression */
+){
+  const char *zIn = "partial index WHERE clauses";
+  if( pNC->ncFlags & NC_IdxExpr )      zIn = "index expressions";
+#ifndef SQLITE_OMIT_CHECK
+  else if( pNC->ncFlags & NC_IsCheck ) zIn = "CHECK constraints";
+#endif
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  else if( pNC->ncFlags & NC_GenCol ) zIn = "generated columns";
+#endif
+  sqlite3ErrorMsg(pParse, "%s prohibited in %s", zMsg, zIn);
+  if( pExpr ) pExpr->op = TK_NULL;
+  sqlite3RecordErrorOffsetOfExpr(pParse->db, pError);
+}
+#define sqlite3ResolveNotValid(P,N,M,X,E,R) \
+  assert( ((X)&~(NC_IsCheck|NC_PartIdx|NC_IdxExpr|NC_GenCol))==0 ); \
+  if( ((N)->ncFlags & (X))!=0 ) notValidImpl(P,N,M,E,R);
+
+/*
+** Expression p should encode a floating point value between 1.0 and 0.0.
+** Return 1024 times this value.  Or return -1 if p is not a floating point
+** value between 1.0 and 0.0.
+*/
+static int exprProbability(Expr *p){
+  double r = -1.0;
+  if( p->op!=TK_FLOAT ) return -1;
+  assert( !ExprHasProperty(p, EP_IntValue) );
+  sqlite3AtoF(p->u.zToken, &r, sqlite3Strlen30(p->u.zToken), SQLITE_UTF8);
+  assert( r>=0.0 );
+  if( r>1.0 ) return -1;
+  return (int)(r*134217728.0);
+}
+
+/*
+** This routine is callback for sqlite3WalkExpr().
+**
+** Resolve symbolic names into TK_COLUMN operators for the current
+** node in the expression tree.  Return 0 to continue the search down
+** the tree or 2 to abort the tree walk.
+**
+** This routine also does error checking and name resolution for
+** function names.  The operator for aggregate functions is changed
+** to TK_AGG_FUNCTION.
+*/
+static int resolveExprStep(Walker *pWalker, Expr *pExpr){
+  NameContext *pNC;
+  Parse *pParse;
+
+  pNC = pWalker->u.pNC;
+  assert( pNC!=0 );
+  pParse = pNC->pParse;
+  assert( pParse==pWalker->pParse );
+
+#ifndef NDEBUG
+  if( pNC->pSrcList && pNC->pSrcList->nAlloc>0 ){
+    SrcList *pSrcList = pNC->pSrcList;
+    int i;
+    for(i=0; i<pNC->pSrcList->nSrc; i++){
+      assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
+    }
+  }
+#endif
+  switch( pExpr->op ){
+
+    /* The special operator TK_ROW means use the rowid for the first
+    ** column in the FROM clause.  This is used by the LIMIT and ORDER BY
+    ** clause processing on UPDATE and DELETE statements, and by
+    ** UPDATE ... FROM statement processing.
+    */
+    case TK_ROW: {
+      SrcList *pSrcList = pNC->pSrcList;
+      SrcItem *pItem;
+      assert( pSrcList && pSrcList->nSrc>=1 );
+      pItem = pSrcList->a;
+      pExpr->op = TK_COLUMN;
+      assert( ExprUseYTab(pExpr) );
+      pExpr->y.pTab = pItem->pSTab;
+      pExpr->iTable = pItem->iCursor;
+      pExpr->iColumn--;
+      pExpr->affExpr = SQLITE_AFF_INTEGER;
+      break;
+    }
+
+    /* An optimization:  Attempt to convert
+    **
+    **      "expr IS NOT NULL"  -->  "TRUE"
+    **      "expr IS NULL"      -->  "FALSE"
+    **
+    ** if we can prove that "expr" is never NULL.  Call this the
+    ** "NOT NULL strength reduction optimization".
+    **
+    ** If this optimization occurs, also restore the NameContext ref-counts
+    ** to the state they where in before the "column" LHS expression was
+    ** resolved.  This prevents "column" from being counted as having been
+    ** referenced, which might prevent a SELECT from being erroneously
+    ** marked as correlated.
+    **
+    ** 2024-03-28: Beware of aggregates.  A bare column of aggregated table
+    ** can still evaluate to NULL even though it is marked as NOT NULL.
+    ** Example:
+    **
+    **       CREATE TABLE t1(a INT NOT NULL);
+    **       SELECT a, a IS NULL, a IS NOT NULL, count(*) FROM t1;
+    **
+    ** The "a IS NULL" and "a IS NOT NULL" expressions cannot be optimized
+    ** here because at the time this case is hit, we do not yet know whether
+    ** or not t1 is being aggregated.  We have to assume the worst and omit
+    ** the optimization.  The only time it is safe to apply this optimization
+    ** is within the WHERE clause.
+    */
+    case TK_NOTNULL:
+    case TK_ISNULL: {
+      int anRef[8];
+      NameContext *p;
+      int i;
+      for(i=0, p=pNC; p && i<ArraySize(anRef); p=p->pNext, i++){
+        anRef[i] = p->nRef;
+      }
+      sqlite3WalkExpr(pWalker, pExpr->pLeft);
+      if( IN_RENAME_OBJECT ) return WRC_Prune;
+      if( sqlite3ExprCanBeNull(pExpr->pLeft) ){
+        /* The expression can be NULL.  So the optimization does not apply */
+        return WRC_Prune;
+      }
+
+      for(i=0, p=pNC; p; p=p->pNext, i++){
+        if( (p->ncFlags & NC_Where)==0 ){
+          return WRC_Prune;  /* Not in a WHERE clause.  Unsafe to optimize. */
+        }
+      }
+      testcase( ExprHasProperty(pExpr, EP_OuterON) );
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+#if TREETRACE_ENABLED
+      if( sqlite3TreeTrace & 0x80000 ){
+        sqlite3DebugPrintf(
+           "NOT NULL strength reduction converts the following to %d:\n",
+           pExpr->op==TK_NOTNULL
+        );
+        sqlite3ShowExpr(pExpr);
+      }
+#endif /* TREETRACE_ENABLED */
+      pExpr->u.iValue = (pExpr->op==TK_NOTNULL);
+      pExpr->flags |= EP_IntValue;
+      pExpr->op = TK_INTEGER;
+      for(i=0, p=pNC; p && i<ArraySize(anRef); p=p->pNext, i++){
+        p->nRef = anRef[i];
+      }
+      sqlite3ExprDelete(pParse->db, pExpr->pLeft);
+      pExpr->pLeft = 0;
+      return WRC_Prune;
+    }
+
+    /* A column name:                    ID
+    ** Or table name and column name:    ID.ID
+    ** Or a database, table and column:  ID.ID.ID
+    **
+    ** The TK_ID and TK_OUT cases are combined so that there will only
+    ** be one call to lookupName().  Then the compiler will in-line
+    ** lookupName() for a size reduction and performance increase.
+    */
+    case TK_ID:
+    case TK_DOT: {
+      const char *zTable;
+      const char *zDb;
+      Expr *pRight;
+
+      if( pExpr->op==TK_ID ){
+        zDb = 0;
+        zTable = 0;
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        pRight = pExpr;
+      }else{
+        Expr *pLeft = pExpr->pLeft;
+        testcase( pNC->ncFlags & NC_IdxExpr );
+        testcase( pNC->ncFlags & NC_GenCol );
+        sqlite3ResolveNotValid(pParse, pNC, "the \".\" operator",
+                               NC_IdxExpr|NC_GenCol, 0, pExpr);
+        pRight = pExpr->pRight;
+        if( pRight->op==TK_ID ){
+          zDb = 0;
+        }else{
+          assert( pRight->op==TK_DOT );
+          assert( !ExprHasProperty(pRight, EP_IntValue) );
+          zDb = pLeft->u.zToken;
+          pLeft = pRight->pLeft;
+          pRight = pRight->pRight;
+        }
+        assert( ExprUseUToken(pLeft) && ExprUseUToken(pRight) );
+        zTable = pLeft->u.zToken;
+        assert( ExprUseYTab(pExpr) );
+        if( IN_RENAME_OBJECT ){
+          sqlite3RenameTokenRemap(pParse, (void*)pExpr, (void*)pRight);
+          sqlite3RenameTokenRemap(pParse, (void*)&pExpr->y.pTab, (void*)pLeft);
+        }
+      }
+      return lookupName(pParse, zDb, zTable, pRight, pNC, pExpr);
+    }
+
+    /* Resolve function names
+    */
+    case TK_FUNCTION: {
+      ExprList *pList;            /* The argument list */
+      int n;                      /* Number of arguments */
+      int no_such_func = 0;       /* True if no such function exists */
+      int wrong_num_args = 0;     /* True if wrong number of arguments */
+      int is_agg = 0;             /* True if is an aggregate function */
+      const char *zId;            /* The function name. */
+      FuncDef *pDef;              /* Information about the function */
+      u8 enc = ENC(pParse->db);   /* The database encoding */
+      int savedAllowFlags = (pNC->ncFlags & (NC_AllowAgg | NC_AllowWin));
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      Window *pWin = (IsWindowFunc(pExpr) ? pExpr->y.pWin : 0);
+#endif
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect|EP_IntValue) );
+      assert( pExpr->pLeft==0 || pExpr->pLeft->op==TK_ORDER );
+      pList = pExpr->x.pList;
+      n = pList ? pList->nExpr : 0;
+      zId = pExpr->u.zToken;
+      pDef = sqlite3FindFunction(pParse->db, zId, n, enc, 0);
+      if( pDef==0 ){
+        pDef = sqlite3FindFunction(pParse->db, zId, -2, enc, 0);
+        if( pDef==0 ){
+          no_such_func = 1;
+        }else{
+          wrong_num_args = 1;
+        }
+      }else{
+        is_agg = pDef->xFinalize!=0;
+        if( pDef->funcFlags & SQLITE_FUNC_UNLIKELY ){
+          ExprSetProperty(pExpr, EP_Unlikely);
+          if( n==2 ){
+            pExpr->iTable = exprProbability(pList->a[1].pExpr);
+            if( pExpr->iTable<0 ){
+              sqlite3ErrorMsg(pParse,
+                "second argument to %#T() must be a "
+                "constant between 0.0 and 1.0", pExpr);
+              pNC->nNcErr++;
+            }
+          }else{
+            /* EVIDENCE-OF: R-61304-29449 The unlikely(X) function is
+            ** equivalent to likelihood(X, 0.0625).
+            ** EVIDENCE-OF: R-01283-11636 The unlikely(X) function is
+            ** short-hand for likelihood(X,0.0625).
+            ** EVIDENCE-OF: R-36850-34127 The likely(X) function is short-hand
+            ** for likelihood(X,0.9375).
+            ** EVIDENCE-OF: R-53436-40973 The likely(X) function is equivalent
+            ** to likelihood(X,0.9375). */
+            /* TUNING: unlikely() probability is 0.0625.  likely() is 0.9375 */
+            pExpr->iTable = pDef->zName[0]=='u' ? 8388608 : 125829120;
+          }
+        }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+        {
+          int auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0,pDef->zName,0);
+          if( auth!=SQLITE_OK ){
+            if( auth==SQLITE_DENY ){
+              sqlite3ErrorMsg(pParse, "not authorized to use function: %#T",
+                                      pExpr);
+              pNC->nNcErr++;
+            }
+            pExpr->op = TK_NULL;
+            return WRC_Prune;
+          }
+        }
+#endif
+
+        /* If the function may call sqlite3_value_subtype(), then set the
+        ** EP_SubtArg flag on all of its argument expressions. This prevents
+        ** where.c from replacing the expression with a value read from an
+        ** index on the same expression, which will not have the correct
+        ** subtype. Also set the flag if the function expression itself is
+        ** an EP_SubtArg expression. In this case subtypes are required as
+        ** the function may return a value with a subtype back to its
+        ** caller using sqlite3_result_value().  */
+        if( (pDef->funcFlags & SQLITE_SUBTYPE)
+         || ExprHasProperty(pExpr, EP_SubtArg)
+        ){
+          int ii;
+          for(ii=0; ii<n; ii++){
+            ExprSetProperty(pList->a[ii].pExpr, EP_SubtArg);
+          }
+        }
+
+        if( pDef->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG) ){
+          /* For the purposes of the EP_ConstFunc flag, date and time
+          ** functions and other functions that change slowly are considered
+          ** constant because they are constant for the duration of one query.
+          ** This allows them to be factored out of inner loops. */
+          ExprSetProperty(pExpr,EP_ConstFunc);
+        }
+        if( (pDef->funcFlags & SQLITE_FUNC_CONSTANT)==0 ){
+          /* Clearly non-deterministic functions like random(), but also
+          ** date/time functions that use 'now', and other functions like
+          ** sqlite_version() that might change over time cannot be used
+          ** in an index or generated column.  Curiously, they can be used
+          ** in a CHECK constraint.  SQLServer, MySQL, and PostgreSQL all
+          ** all this. */
+          sqlite3ResolveNotValid(pParse, pNC, "non-deterministic functions",
+                                 NC_IdxExpr|NC_PartIdx|NC_GenCol, 0, pExpr);
+        }else{
+          assert( (NC_SelfRef & 0xff)==NC_SelfRef ); /* Must fit in 8 bits */
+          pExpr->op2 = pNC->ncFlags & NC_SelfRef;
+          if( pNC->ncFlags & NC_FromDDL ) ExprSetProperty(pExpr, EP_FromDDL);
+        }
+        if( (pDef->funcFlags & SQLITE_FUNC_INTERNAL)!=0
+         && pParse->nested==0
+         && (pParse->db->mDbFlags & DBFLAG_InternalFunc)==0
+        ){
+          /* Internal-use-only functions are disallowed unless the
+          ** SQL is being compiled using sqlite3NestedParse() or
+          ** the SQLITE_TESTCTRL_INTERNAL_FUNCTIONS test-control has be
+          ** used to activate internal functions for testing purposes */
+          no_such_func = 1;
+          pDef = 0;
+        }else
+        if( (pDef->funcFlags & (SQLITE_FUNC_DIRECT|SQLITE_FUNC_UNSAFE))!=0
+         && !IN_RENAME_OBJECT
+        ){
+          sqlite3ExprFunctionUsable(pParse, pExpr, pDef);
+        }
+      }
+
+      if( 0==IN_RENAME_OBJECT ){
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        assert( is_agg==0 || (pDef->funcFlags & SQLITE_FUNC_MINMAX)
+          || (pDef->xValue==0 && pDef->xInverse==0)
+          || (pDef->xValue && pDef->xInverse && pDef->xSFunc && pDef->xFinalize)
+        );
+        if( pDef && pDef->xValue==0 && pWin ){
+          sqlite3ErrorMsg(pParse,
+              "%#T() may not be used as a window function", pExpr
+          );
+          pNC->nNcErr++;
+        }else if(
+              (is_agg && (pNC->ncFlags & NC_AllowAgg)==0)
+           || (is_agg && (pDef->funcFlags&SQLITE_FUNC_WINDOW) && !pWin)
+           || (is_agg && pWin && (pNC->ncFlags & NC_AllowWin)==0)
+        ){
+          const char *zType;
+          if( (pDef->funcFlags & SQLITE_FUNC_WINDOW) || pWin ){
+            zType = "window";
+          }else{
+            zType = "aggregate";
+          }
+          sqlite3ErrorMsg(pParse, "misuse of %s function %#T()",zType,pExpr);
+          pNC->nNcErr++;
+          is_agg = 0;
+        }
+#else
+        if( (is_agg && (pNC->ncFlags & NC_AllowAgg)==0) ){
+          sqlite3ErrorMsg(pParse,"misuse of aggregate function %#T()",pExpr);
+          pNC->nNcErr++;
+          is_agg = 0;
+        }
+#endif
+        else if( no_such_func && pParse->db->init.busy==0
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+                  && pParse->explain==0
+#endif
+        ){
+          sqlite3ErrorMsg(pParse, "no such function: %#T", pExpr);
+          pNC->nNcErr++;
+        }else if( wrong_num_args ){
+          sqlite3ErrorMsg(pParse,"wrong number of arguments to function %#T()",
+               pExpr);
+          pNC->nNcErr++;
+        }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        else if( is_agg==0 && ExprHasProperty(pExpr, EP_WinFunc) ){
+          sqlite3ErrorMsg(pParse,
+              "FILTER may not be used with non-aggregate %#T()",
+              pExpr
+          );
+          pNC->nNcErr++;
+        }
+#endif
+        else if( is_agg==0 && pExpr->pLeft ){
+          sqlite3ExprOrderByAggregateError(pParse, pExpr);
+          pNC->nNcErr++;
+        }
+        if( is_agg ){
+          /* Window functions may not be arguments of aggregate functions.
+          ** Or arguments of other window functions. But aggregate functions
+          ** may be arguments for window functions.  */
+#ifndef SQLITE_OMIT_WINDOWFUNC
+          pNC->ncFlags &= ~(NC_AllowWin | (!pWin ? NC_AllowAgg : 0));
+#else
+          pNC->ncFlags &= ~NC_AllowAgg;
+#endif
+        }
+      }
+      else if( ExprHasProperty(pExpr, EP_WinFunc) || pExpr->pLeft ){
+        is_agg = 1;
+      }
+      sqlite3WalkExprList(pWalker, pList);
+      if( is_agg ){
+        if( pExpr->pLeft ){
+          assert( pExpr->pLeft->op==TK_ORDER );
+          assert( ExprUseXList(pExpr->pLeft) );
+          sqlite3WalkExprList(pWalker, pExpr->pLeft->x.pList);
+        }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        if( pWin && pParse->nErr==0 ){
+          Select *pSel = pNC->pWinSelect;
+          assert( ExprUseYWin(pExpr) && pWin==pExpr->y.pWin );
+          if( IN_RENAME_OBJECT==0 ){
+            sqlite3WindowUpdate(pParse, pSel ? pSel->pWinDefn : 0, pWin, pDef);
+            if( pParse->db->mallocFailed ) break;
+          }
+          sqlite3WalkExprList(pWalker, pWin->pPartition);
+          sqlite3WalkExprList(pWalker, pWin->pOrderBy);
+          sqlite3WalkExpr(pWalker, pWin->pFilter);
+          sqlite3WindowLink(pSel, pWin);
+          pNC->ncFlags |= NC_HasWin;
+        }else
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+        {
+          NameContext *pNC2;          /* For looping up thru outer contexts */
+          pExpr->op = TK_AGG_FUNCTION;
+          pExpr->op2 = 0;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+          if( ExprHasProperty(pExpr, EP_WinFunc) ){
+            sqlite3WalkExpr(pWalker, pExpr->y.pWin->pFilter);
+          }
+#endif
+          pNC2 = pNC;
+          while( pNC2
+              && sqlite3ReferencesSrcList(pParse, pExpr, pNC2->pSrcList)==0
+          ){
+            pExpr->op2 += (1 + pNC2->nNestedSelect);
+            pNC2 = pNC2->pNext;
+          }
+          assert( pDef!=0 || IN_RENAME_OBJECT );
+          if( pNC2 && pDef ){
+            pExpr->op2 += pNC2->nNestedSelect;
+            assert( SQLITE_FUNC_MINMAX==NC_MinMaxAgg );
+            assert( SQLITE_FUNC_ANYORDER==NC_OrderAgg );
+            testcase( (pDef->funcFlags & SQLITE_FUNC_MINMAX)!=0 );
+            testcase( (pDef->funcFlags & SQLITE_FUNC_ANYORDER)!=0 );
+            pNC2->ncFlags |= NC_HasAgg
+              | ((pDef->funcFlags^SQLITE_FUNC_ANYORDER)
+                  & (SQLITE_FUNC_MINMAX|SQLITE_FUNC_ANYORDER));
+          }
+        }
+        pNC->ncFlags |= savedAllowFlags;
+      }
+      /* FIX ME:  Compute pExpr->affinity based on the expected return
+      ** type of the function
+      */
+      return WRC_Prune;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_SELECT:
+    case TK_EXISTS:  testcase( pExpr->op==TK_EXISTS );
+#endif
+    case TK_IN: {
+      testcase( pExpr->op==TK_IN );
+      if( ExprUseXSelect(pExpr) ){
+        int nRef = pNC->nRef;
+        testcase( pNC->ncFlags & NC_IsCheck );
+        testcase( pNC->ncFlags & NC_PartIdx );
+        testcase( pNC->ncFlags & NC_IdxExpr );
+        testcase( pNC->ncFlags & NC_GenCol );
+        assert( pExpr->x.pSelect );
+        if( pNC->ncFlags & NC_SelfRef ){
+          notValidImpl(pParse, pNC, "subqueries", pExpr, pExpr);
+        }else{
+          sqlite3WalkSelect(pWalker, pExpr->x.pSelect);
+        }
+        assert( pNC->nRef>=nRef );
+        if( nRef!=pNC->nRef ){
+          ExprSetProperty(pExpr, EP_VarSelect);
+          pExpr->x.pSelect->selFlags |= SF_Correlated;
+        }
+        pNC->ncFlags |= NC_Subquery;
+      }
+      break;
+    }
+    case TK_VARIABLE: {
+      testcase( pNC->ncFlags & NC_IsCheck );
+      testcase( pNC->ncFlags & NC_PartIdx );
+      testcase( pNC->ncFlags & NC_IdxExpr );
+      testcase( pNC->ncFlags & NC_GenCol );
+      sqlite3ResolveNotValid(pParse, pNC, "parameters",
+               NC_IsCheck|NC_PartIdx|NC_IdxExpr|NC_GenCol, pExpr, pExpr);
+      break;
+    }
+    case TK_IS:
+    case TK_ISNOT: {
+      Expr *pRight = sqlite3ExprSkipCollateAndLikely(pExpr->pRight);
+      assert( !ExprHasProperty(pExpr, EP_Reduced) );
+      /* Handle special cases of "x IS TRUE", "x IS FALSE", "x IS NOT TRUE",
+      ** and "x IS NOT FALSE". */
+      if( ALWAYS(pRight) && (pRight->op==TK_ID || pRight->op==TK_TRUEFALSE) ){
+        int rc = resolveExprStep(pWalker, pRight);
+        if( rc==WRC_Abort ) return WRC_Abort;
+        if( pRight->op==TK_TRUEFALSE ){
+          pExpr->op2 = pExpr->op;
+          pExpr->op = TK_TRUTH;
+          return WRC_Continue;
+        }
+      }
+      /* no break */ deliberate_fall_through
+    }
+    case TK_BETWEEN:
+    case TK_EQ:
+    case TK_NE:
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE: {
+      int nLeft, nRight;
+      if( pParse->db->mallocFailed ) break;
+      assert( pExpr->pLeft!=0 );
+      nLeft = sqlite3ExprVectorSize(pExpr->pLeft);
+      if( pExpr->op==TK_BETWEEN ){
+        assert( ExprUseXList(pExpr) );
+        nRight = sqlite3ExprVectorSize(pExpr->x.pList->a[0].pExpr);
+        if( nRight==nLeft ){
+          nRight = sqlite3ExprVectorSize(pExpr->x.pList->a[1].pExpr);
+        }
+      }else{
+        assert( pExpr->pRight!=0 );
+        nRight = sqlite3ExprVectorSize(pExpr->pRight);
+      }
+      if( nLeft!=nRight ){
+        testcase( pExpr->op==TK_EQ );
+        testcase( pExpr->op==TK_NE );
+        testcase( pExpr->op==TK_LT );
+        testcase( pExpr->op==TK_LE );
+        testcase( pExpr->op==TK_GT );
+        testcase( pExpr->op==TK_GE );
+        testcase( pExpr->op==TK_IS );
+        testcase( pExpr->op==TK_ISNOT );
+        testcase( pExpr->op==TK_BETWEEN );
+        sqlite3ErrorMsg(pParse, "row value misused");
+        sqlite3RecordErrorOffsetOfExpr(pParse->db, pExpr);
+      }
+      break;
+    }
+  }
+  assert( pParse->db->mallocFailed==0 || pParse->nErr!=0 );
+  return pParse->nErr ? WRC_Abort : WRC_Continue;
+}
+
+/*
+** pEList is a list of expressions which are really the result set of the
+** a SELECT statement.  pE is a term in an ORDER BY or GROUP BY clause.
+** This routine checks to see if pE is a simple identifier which corresponds
+** to the AS-name of one of the terms of the expression list.  If it is,
+** this routine return an integer between 1 and N where N is the number of
+** elements in pEList, corresponding to the matching entry.  If there is
+** no match, or if pE is not a simple identifier, then this routine
+** return 0.
+**
+** pEList has been resolved.  pE has not.
+*/
+static int resolveAsName(
+  Parse *pParse,     /* Parsing context for error messages */
+  ExprList *pEList,  /* List of expressions to scan */
+  Expr *pE           /* Expression we are trying to match */
+){
+  int i;             /* Loop counter */
+
+  UNUSED_PARAMETER(pParse);
+
+  if( pE->op==TK_ID ){
+    const char *zCol;
+    assert( !ExprHasProperty(pE, EP_IntValue) );
+    zCol = pE->u.zToken;
+    for(i=0; i<pEList->nExpr; i++){
+      if( pEList->a[i].fg.eEName==ENAME_NAME
+       && sqlite3_stricmp(pEList->a[i].zEName, zCol)==0
+      ){
+        return i+1;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** pE is a pointer to an expression which is a single term in the
+** ORDER BY of a compound SELECT.  The expression has not been
+** name resolved.
+**
+** At the point this routine is called, we already know that the
+** ORDER BY term is not an integer index into the result set.  That
+** case is handled by the calling routine.
+**
+** Attempt to match pE against result set columns in the left-most
+** SELECT statement.  Return the index i of the matching column,
+** as an indication to the caller that it should sort by the i-th column.
+** The left-most column is 1.  In other words, the value returned is the
+** same integer value that would be used in the SQL statement to indicate
+** the column.
+**
+** If there is no match, return 0.  Return -1 if an error occurs.
+*/
+static int resolveOrderByTermToExprList(
+  Parse *pParse,     /* Parsing context for error messages */
+  Select *pSelect,   /* The SELECT statement with the ORDER BY clause */
+  Expr *pE           /* The specific ORDER BY term */
+){
+  int i;             /* Loop counter */
+  ExprList *pEList;  /* The columns of the result set */
+  NameContext nc;    /* Name context for resolving pE */
+  sqlite3 *db;       /* Database connection */
+  int rc;            /* Return code from subprocedures */
+  u8 savedSuppErr;   /* Saved value of db->suppressErr */
+
+  assert( sqlite3ExprIsInteger(pE, &i, 0)==0 );
+  pEList = pSelect->pEList;
+
+  /* Resolve all names in the ORDER BY term expression
+  */
+  memset(&nc, 0, sizeof(nc));
+  nc.pParse = pParse;
+  nc.pSrcList = pSelect->pSrc;
+  nc.uNC.pEList = pEList;
+  nc.ncFlags = NC_AllowAgg|NC_UEList|NC_NoSelect;
+  nc.nNcErr = 0;
+  db = pParse->db;
+  savedSuppErr = db->suppressErr;
+  db->suppressErr = 1;
+  rc = sqlite3ResolveExprNames(&nc, pE);
+  db->suppressErr = savedSuppErr;
+  if( rc ) return 0;
+
+  /* Try to match the ORDER BY expression against an expression
+  ** in the result set.  Return an 1-based index of the matching
+  ** result-set entry.
+  */
+  for(i=0; i<pEList->nExpr; i++){
+    if( sqlite3ExprCompare(0, pEList->a[i].pExpr, pE, -1)<2 ){
+      return i+1;
+    }
+  }
+
+  /* If no match, return 0. */
+  return 0;
+}
+
+/*
+** Generate an ORDER BY or GROUP BY term out-of-range error.
+*/
+static void resolveOutOfRangeError(
+  Parse *pParse,         /* The error context into which to write the error */
+  const char *zType,     /* "ORDER" or "GROUP" */
+  int i,                 /* The index (1-based) of the term out of range */
+  int mx,                /* Largest permissible value of i */
+  Expr *pError           /* Associate the error with the expression */
+){
+  sqlite3ErrorMsg(pParse,
+    "%r %s BY term out of range - should be "
+    "between 1 and %d", i, zType, mx);
+  sqlite3RecordErrorOffsetOfExpr(pParse->db, pError);
+}
+
+/*
+** Analyze the ORDER BY clause in a compound SELECT statement.   Modify
+** each term of the ORDER BY clause is a constant integer between 1
+** and N where N is the number of columns in the compound SELECT.
+**
+** ORDER BY terms that are already an integer between 1 and N are
+** unmodified.  ORDER BY terms that are integers outside the range of
+** 1 through N generate an error.  ORDER BY terms that are expressions
+** are matched against result set expressions of compound SELECT
+** beginning with the left-most SELECT and working toward the right.
+** At the first match, the ORDER BY expression is transformed into
+** the integer column number.
+**
+** Return the number of errors seen.
+*/
+static int resolveCompoundOrderBy(
+  Parse *pParse,        /* Parsing context.  Leave error messages here */
+  Select *pSelect       /* The SELECT statement containing the ORDER BY */
+){
+  int i;
+  ExprList *pOrderBy;
+  ExprList *pEList;
+  sqlite3 *db;
+  int moreToDo = 1;
+
+  pOrderBy = pSelect->pOrderBy;
+  if( pOrderBy==0 ) return 0;
+  db = pParse->db;
+  if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many terms in ORDER BY clause");
+    return 1;
+  }
+  for(i=0; i<pOrderBy->nExpr; i++){
+    pOrderBy->a[i].fg.done = 0;
+  }
+  pSelect->pNext = 0;
+  while( pSelect->pPrior ){
+    pSelect->pPrior->pNext = pSelect;
+    pSelect = pSelect->pPrior;
+  }
+  while( pSelect && moreToDo ){
+    struct ExprList_item *pItem;
+    moreToDo = 0;
+    pEList = pSelect->pEList;
+    assert( pEList!=0 );
+    for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
+      int iCol = -1;
+      Expr *pE, *pDup;
+      if( pItem->fg.done ) continue;
+      pE = sqlite3ExprSkipCollateAndLikely(pItem->pExpr);
+      if( NEVER(pE==0) ) continue;
+      if( sqlite3ExprIsInteger(pE, &iCol, 0) ){
+        if( iCol<=0 || iCol>pEList->nExpr ){
+          resolveOutOfRangeError(pParse, "ORDER", i+1, pEList->nExpr, pE);
+          return 1;
+        }
+      }else{
+        iCol = resolveAsName(pParse, pEList, pE);
+        if( iCol==0 ){
+          /* Now test if expression pE matches one of the values returned
+          ** by pSelect. In the usual case this is done by duplicating the
+          ** expression, resolving any symbols in it, and then comparing
+          ** it against each expression returned by the SELECT statement.
+          ** Once the comparisons are finished, the duplicate expression
+          ** is deleted.
+          **
+          ** If this is running as part of an ALTER TABLE operation and
+          ** the symbols resolve successfully, also resolve the symbols in the
+          ** actual expression. This allows the code in alter.c to modify
+          ** column references within the ORDER BY expression as required.  */
+          pDup = sqlite3ExprDup(db, pE, 0);
+          if( !db->mallocFailed ){
+            assert(pDup);
+            iCol = resolveOrderByTermToExprList(pParse, pSelect, pDup);
+            if( IN_RENAME_OBJECT && iCol>0 ){
+              resolveOrderByTermToExprList(pParse, pSelect, pE);
+            }
+          }
+          sqlite3ExprDelete(db, pDup);
+        }
+      }
+      if( iCol>0 ){
+        /* Convert the ORDER BY term into an integer column number iCol,
+        ** taking care to preserve the COLLATE clause if it exists. */
+        if( !IN_RENAME_OBJECT ){
+          Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
+          if( pNew==0 ) return 1;
+          pNew->flags |= EP_IntValue;
+          pNew->u.iValue = iCol;
+          if( pItem->pExpr==pE ){
+            pItem->pExpr = pNew;
+          }else{
+            Expr *pParent = pItem->pExpr;
+            assert( pParent->op==TK_COLLATE );
+            while( pParent->pLeft->op==TK_COLLATE ) pParent = pParent->pLeft;
+            assert( pParent->pLeft==pE );
+            pParent->pLeft = pNew;
+          }
+          sqlite3ExprDelete(db, pE);
+          pItem->u.x.iOrderByCol = (u16)iCol;
+        }
+        pItem->fg.done = 1;
+      }else{
+        moreToDo = 1;
+      }
+    }
+    pSelect = pSelect->pNext;
+  }
+  for(i=0; i<pOrderBy->nExpr; i++){
+    if( pOrderBy->a[i].fg.done==0 ){
+      sqlite3ErrorMsg(pParse, "%r ORDER BY term does not match any "
+            "column in the result set", i+1);
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Check every term in the ORDER BY or GROUP BY clause pOrderBy of
+** the SELECT statement pSelect.  If any term is reference to a
+** result set expression (as determined by the ExprList.a.u.x.iOrderByCol
+** field) then convert that term into a copy of the corresponding result set
+** column.
+**
+** If any errors are detected, add an error message to pParse and
+** return non-zero.  Return zero if no errors are seen.
+*/
+SQLITE_PRIVATE int sqlite3ResolveOrderGroupBy(
+  Parse *pParse,        /* Parsing context.  Leave error messages here */
+  Select *pSelect,      /* The SELECT statement containing the clause */
+  ExprList *pOrderBy,   /* The ORDER BY or GROUP BY clause to be processed */
+  const char *zType     /* "ORDER" or "GROUP" */
+){
+  int i;
+  sqlite3 *db = pParse->db;
+  ExprList *pEList;
+  struct ExprList_item *pItem;
+
+  if( pOrderBy==0 || pParse->db->mallocFailed || IN_RENAME_OBJECT ) return 0;
+  if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
+    return 1;
+  }
+  pEList = pSelect->pEList;
+  assert( pEList!=0 );  /* sqlite3SelectNew() guarantees this */
+  for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
+    if( pItem->u.x.iOrderByCol ){
+      if( pItem->u.x.iOrderByCol>pEList->nExpr ){
+        resolveOutOfRangeError(pParse, zType, i+1, pEList->nExpr, 0);
+        return 1;
+      }
+      resolveAlias(pParse, pEList, pItem->u.x.iOrderByCol-1, pItem->pExpr,0);
+    }
+  }
+  return 0;
+}
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Walker callback for windowRemoveExprFromSelect().
+*/
+static int resolveRemoveWindowsCb(Walker *pWalker, Expr *pExpr){
+  UNUSED_PARAMETER(pWalker);
+  if( ExprHasProperty(pExpr, EP_WinFunc) ){
+    Window *pWin = pExpr->y.pWin;
+    sqlite3WindowUnlinkFromSelect(pWin);
+  }
+  return WRC_Continue;
+}
+
+/*
+** Remove any Window objects owned by the expression pExpr from the
+** Select.pWin list of Select object pSelect.
+*/
+static void windowRemoveExprFromSelect(Select *pSelect, Expr *pExpr){
+  if( pSelect->pWin ){
+    Walker sWalker;
+    memset(&sWalker, 0, sizeof(Walker));
+    sWalker.xExprCallback = resolveRemoveWindowsCb;
+    sWalker.u.pSelect = pSelect;
+    sqlite3WalkExpr(&sWalker, pExpr);
+  }
+}
+#else
+# define windowRemoveExprFromSelect(a, b)
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** pOrderBy is an ORDER BY or GROUP BY clause in SELECT statement pSelect.
+** The Name context of the SELECT statement is pNC.  zType is either
+** "ORDER" or "GROUP" depending on which type of clause pOrderBy is.
+**
+** This routine resolves each term of the clause into an expression.
+** If the order-by term is an integer I between 1 and N (where N is the
+** number of columns in the result set of the SELECT) then the expression
+** in the resolution is a copy of the I-th result-set expression.  If
+** the order-by term is an identifier that corresponds to the AS-name of
+** a result-set expression, then the term resolves to a copy of the
+** result-set expression.  Otherwise, the expression is resolved in
+** the usual way - using sqlite3ResolveExprNames().
+**
+** This routine returns the number of errors.  If errors occur, then
+** an appropriate error message might be left in pParse.  (OOM errors
+** excepted.)
+*/
+static int resolveOrderGroupBy(
+  NameContext *pNC,     /* The name context of the SELECT statement */
+  Select *pSelect,      /* The SELECT statement holding pOrderBy */
+  ExprList *pOrderBy,   /* An ORDER BY or GROUP BY clause to resolve */
+  const char *zType     /* Either "ORDER" or "GROUP", as appropriate */
+){
+  int i, j;                      /* Loop counters */
+  int iCol;                      /* Column number */
+  struct ExprList_item *pItem;   /* A term of the ORDER BY clause */
+  Parse *pParse;                 /* Parsing context */
+  int nResult;                   /* Number of terms in the result set */
+
+  assert( pOrderBy!=0 );
+  nResult = pSelect->pEList->nExpr;
+  pParse = pNC->pParse;
+  for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
+    Expr *pE = pItem->pExpr;
+    Expr *pE2 = sqlite3ExprSkipCollateAndLikely(pE);
+    if( NEVER(pE2==0) ) continue;
+    if( zType[0]!='G' ){
+      iCol = resolveAsName(pParse, pSelect->pEList, pE2);
+      if( iCol>0 ){
+        /* If an AS-name match is found, mark this ORDER BY column as being
+        ** a copy of the iCol-th result-set column.  The subsequent call to
+        ** sqlite3ResolveOrderGroupBy() will convert the expression to a
+        ** copy of the iCol-th result-set expression. */
+        pItem->u.x.iOrderByCol = (u16)iCol;
+        continue;
+      }
+    }
+    if( sqlite3ExprIsInteger(pE2, &iCol, 0) ){
+      /* The ORDER BY term is an integer constant.  Again, set the column
+      ** number so that sqlite3ResolveOrderGroupBy() will convert the
+      ** order-by term to a copy of the result-set expression */
+      if( iCol<1 || iCol>0xffff ){
+        resolveOutOfRangeError(pParse, zType, i+1, nResult, pE2);
+        return 1;
+      }
+      pItem->u.x.iOrderByCol = (u16)iCol;
+      continue;
+    }
+
+    /* Otherwise, treat the ORDER BY term as an ordinary expression */
+    pItem->u.x.iOrderByCol = 0;
+    if( sqlite3ResolveExprNames(pNC, pE) ){
+      return 1;
+    }
+    for(j=0; j<pSelect->pEList->nExpr; j++){
+      if( sqlite3ExprCompare(0, pE, pSelect->pEList->a[j].pExpr, -1)==0 ){
+        /* Since this expression is being changed into a reference
+        ** to an identical expression in the result set, remove all Window
+        ** objects belonging to the expression from the Select.pWin list. */
+        windowRemoveExprFromSelect(pSelect, pE);
+        pItem->u.x.iOrderByCol = j+1;
+      }
+    }
+  }
+  return sqlite3ResolveOrderGroupBy(pParse, pSelect, pOrderBy, zType);
+}
+
+/*
+** Resolve names in the SELECT statement p and all of its descendants.
+*/
+static int resolveSelectStep(Walker *pWalker, Select *p){
+  NameContext *pOuterNC;  /* Context that contains this SELECT */
+  NameContext sNC;        /* Name context of this SELECT */
+  int isCompound;         /* True if p is a compound select */
+  int nCompound;          /* Number of compound terms processed so far */
+  Parse *pParse;          /* Parsing context */
+  int i;                  /* Loop counter */
+  ExprList *pGroupBy;     /* The GROUP BY clause */
+  Select *pLeftmost;      /* Left-most of SELECT of a compound */
+  sqlite3 *db;            /* Database connection */
+
+
+  assert( p!=0 );
+  if( p->selFlags & SF_Resolved ){
+    return WRC_Prune;
+  }
+  pOuterNC = pWalker->u.pNC;
+  pParse = pWalker->pParse;
+  db = pParse->db;
+
+  /* Normally sqlite3SelectExpand() will be called first and will have
+  ** already expanded this SELECT.  However, if this is a subquery within
+  ** an expression, sqlite3ResolveExprNames() will be called without a
+  ** prior call to sqlite3SelectExpand().  When that happens, let
+  ** sqlite3SelectPrep() do all of the processing for this SELECT.
+  ** sqlite3SelectPrep() will invoke both sqlite3SelectExpand() and
+  ** this routine in the correct order.
+  */
+  if( (p->selFlags & SF_Expanded)==0 ){
+    sqlite3SelectPrep(pParse, p, pOuterNC);
+    return pParse->nErr ? WRC_Abort : WRC_Prune;
+  }
+
+  isCompound = p->pPrior!=0;
+  nCompound = 0;
+  pLeftmost = p;
+  while( p ){
+    assert( (p->selFlags & SF_Expanded)!=0 );
+    assert( (p->selFlags & SF_Resolved)==0 );
+    p->selFlags |= SF_Resolved;
+
+    /* Resolve the expressions in the LIMIT and OFFSET clauses. These
+    ** are not allowed to refer to any names, so pass an empty NameContext.
+    */
+    memset(&sNC, 0, sizeof(sNC));
+    sNC.pParse = pParse;
+    sNC.pWinSelect = p;
+    if( sqlite3ResolveExprNames(&sNC, p->pLimit) ){
+      return WRC_Abort;
+    }
+
+    /* If the SF_Converted flags is set, then this Select object was
+    ** was created by the convertCompoundSelectToSubquery() function.
+    ** In this case the ORDER BY clause (p->pOrderBy) should be resolved
+    ** as if it were part of the sub-query, not the parent. This block
+    ** moves the pOrderBy down to the sub-query. It will be moved back
+    ** after the names have been resolved.  */
+    if( p->selFlags & SF_Converted ){
+      Select *pSub;
+      assert( p->pSrc->a[0].fg.isSubquery );
+      assert( p->pSrc->a[0].u4.pSubq!=0 );
+      pSub = p->pSrc->a[0].u4.pSubq->pSelect;
+      assert( pSub!=0 );
+      assert( p->pSrc->nSrc==1 && p->pOrderBy );
+      assert( pSub->pPrior && pSub->pOrderBy==0 );
+      pSub->pOrderBy = p->pOrderBy;
+      p->pOrderBy = 0;
+    }
+
+    /* Recursively resolve names in all subqueries in the FROM clause
+    */
+    if( pOuterNC ) pOuterNC->nNestedSelect++;
+    for(i=0; i<p->pSrc->nSrc; i++){
+      SrcItem *pItem = &p->pSrc->a[i];
+      assert( pItem->zName!=0
+              || pItem->fg.isSubquery );  /* Test of tag-20240424-1*/
+      if( pItem->fg.isSubquery
+       && (pItem->u4.pSubq->pSelect->selFlags & SF_Resolved)==0
+      ){
+        int nRef = pOuterNC ? pOuterNC->nRef : 0;
+        const char *zSavedContext = pParse->zAuthContext;
+
+        if( pItem->zName ) pParse->zAuthContext = pItem->zName;
+        sqlite3ResolveSelectNames(pParse, pItem->u4.pSubq->pSelect, pOuterNC);
+        pParse->zAuthContext = zSavedContext;
+        if( pParse->nErr ) return WRC_Abort;
+        assert( db->mallocFailed==0 );
+
+        /* If the number of references to the outer context changed when
+        ** expressions in the sub-select were resolved, the sub-select
+        ** is correlated. It is not required to check the refcount on any
+        ** but the innermost outer context object, as lookupName() increments
+        ** the refcount on all contexts between the current one and the
+        ** context containing the column when it resolves a name. */
+        if( pOuterNC ){
+          assert( pItem->fg.isCorrelated==0 && pOuterNC->nRef>=nRef );
+          pItem->fg.isCorrelated = (pOuterNC->nRef>nRef);
+        }
+      }
+    }
+    if( pOuterNC && ALWAYS(pOuterNC->nNestedSelect>0) ){
+      pOuterNC->nNestedSelect--;
+    }
+
+    /* Set up the local name-context to pass to sqlite3ResolveExprNames() to
+    ** resolve the result-set expression list.
+    */
+    sNC.ncFlags = NC_AllowAgg|NC_AllowWin;
+    sNC.pSrcList = p->pSrc;
+    sNC.pNext = pOuterNC;
+
+    /* Resolve names in the result set. */
+    if( sqlite3ResolveExprListNames(&sNC, p->pEList) ) return WRC_Abort;
+    sNC.ncFlags &= ~NC_AllowWin;
+
+    /* If there are no aggregate functions in the result-set, and no GROUP BY
+    ** expression, do not allow aggregates in any of the other expressions.
+    */
+    assert( (p->selFlags & SF_Aggregate)==0 );
+    pGroupBy = p->pGroupBy;
+    if( pGroupBy || (sNC.ncFlags & NC_HasAgg)!=0 ){
+      assert( NC_MinMaxAgg==SF_MinMaxAgg );
+      assert( NC_OrderAgg==SF_OrderByReqd );
+      p->selFlags |= SF_Aggregate | (sNC.ncFlags&(NC_MinMaxAgg|NC_OrderAgg));
+    }else{
+      sNC.ncFlags &= ~NC_AllowAgg;
+    }
+
+    /* Add the output column list to the name-context before parsing the
+    ** other expressions in the SELECT statement. This is so that
+    ** expressions in the WHERE clause (etc.) can refer to expressions by
+    ** aliases in the result set.
+    **
+    ** Minor point: If this is the case, then the expression will be
+    ** re-evaluated for each reference to it.
+    */
+    assert( (sNC.ncFlags & (NC_UAggInfo|NC_UUpsert|NC_UBaseReg))==0 );
+    sNC.uNC.pEList = p->pEList;
+    sNC.ncFlags |= NC_UEList;
+    if( p->pHaving ){
+      if( (p->selFlags & SF_Aggregate)==0 ){
+        sqlite3ErrorMsg(pParse, "HAVING clause on a non-aggregate query");
+        return WRC_Abort;
+      }
+      if( sqlite3ResolveExprNames(&sNC, p->pHaving) ) return WRC_Abort;
+    }
+    sNC.ncFlags |= NC_Where;
+    if( sqlite3ResolveExprNames(&sNC, p->pWhere) ) return WRC_Abort;
+    sNC.ncFlags &= ~NC_Where;
+
+    /* Resolve names in table-valued-function arguments */
+    for(i=0; i<p->pSrc->nSrc; i++){
+      SrcItem *pItem = &p->pSrc->a[i];
+      if( pItem->fg.isTabFunc
+       && sqlite3ResolveExprListNames(&sNC, pItem->u1.pFuncArg)
+      ){
+        return WRC_Abort;
+      }
+    }
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( IN_RENAME_OBJECT ){
+      Window *pWin;
+      for(pWin=p->pWinDefn; pWin; pWin=pWin->pNextWin){
+        if( sqlite3ResolveExprListNames(&sNC, pWin->pOrderBy)
+         || sqlite3ResolveExprListNames(&sNC, pWin->pPartition)
+        ){
+          return WRC_Abort;
+        }
+      }
+    }
+#endif
+
+    /* The ORDER BY and GROUP BY clauses may not refer to terms in
+    ** outer queries
+    */
+    sNC.pNext = 0;
+    sNC.ncFlags |= NC_AllowAgg|NC_AllowWin;
+
+    /* If this is a converted compound query, move the ORDER BY clause from
+    ** the sub-query back to the parent query. At this point each term
+    ** within the ORDER BY clause has been transformed to an integer value.
+    ** These integers will be replaced by copies of the corresponding result
+    ** set expressions by the call to resolveOrderGroupBy() below.  */
+    if( p->selFlags & SF_Converted ){
+      Select *pSub;
+      assert( p->pSrc->a[0].fg.isSubquery );
+      pSub = p->pSrc->a[0].u4.pSubq->pSelect;
+      assert( pSub!=0 );
+      p->pOrderBy = pSub->pOrderBy;
+      pSub->pOrderBy = 0;
+    }
+
+    /* Process the ORDER BY clause for singleton SELECT statements.
+    ** The ORDER BY clause for compounds SELECT statements is handled
+    ** below, after all of the result-sets for all of the elements of
+    ** the compound have been resolved.
+    **
+    ** If there is an ORDER BY clause on a term of a compound-select other
+    ** than the right-most term, then that is a syntax error.  But the error
+    ** is not detected until much later, and so we need to go ahead and
+    ** resolve those symbols on the incorrect ORDER BY for consistency.
+    */
+    if( p->pOrderBy!=0
+     && isCompound<=nCompound  /* Defer right-most ORDER BY of a compound */
+     && resolveOrderGroupBy(&sNC, p, p->pOrderBy, "ORDER")
+    ){
+      return WRC_Abort;
+    }
+    if( db->mallocFailed ){
+      return WRC_Abort;
+    }
+    sNC.ncFlags &= ~NC_AllowWin;
+
+    /* Resolve the GROUP BY clause.  At the same time, make sure
+    ** the GROUP BY clause does not contain aggregate functions.
+    */
+    if( pGroupBy ){
+      struct ExprList_item *pItem;
+
+      if( resolveOrderGroupBy(&sNC, p, pGroupBy, "GROUP") || db->mallocFailed ){
+        return WRC_Abort;
+      }
+      for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
+        if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
+          sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
+              "the GROUP BY clause");
+          return WRC_Abort;
+        }
+      }
+    }
+
+    /* If this is part of a compound SELECT, check that it has the right
+    ** number of expressions in the select list. */
+    if( p->pNext && p->pEList->nExpr!=p->pNext->pEList->nExpr ){
+      sqlite3SelectWrongNumTermsError(pParse, p->pNext);
+      return WRC_Abort;
+    }
+
+    /* Advance to the next term of the compound
+    */
+    p = p->pPrior;
+    nCompound++;
+  }
+
+  /* Resolve the ORDER BY on a compound SELECT after all terms of
+  ** the compound have been resolved.
+  */
+  if( isCompound && resolveCompoundOrderBy(pParse, pLeftmost) ){
+    return WRC_Abort;
+  }
+
+  return WRC_Prune;
+}
+
+/*
+** This routine walks an expression tree and resolves references to
+** table columns and result-set columns.  At the same time, do error
+** checking on function usage and set a flag if any aggregate functions
+** are seen.
+**
+** To resolve table columns references we look for nodes (or subtrees) of the
+** form X.Y.Z or Y.Z or just Z where
+**
+**      X:   The name of a database.  Ex:  "main" or "temp" or
+**           the symbolic name assigned to an ATTACH-ed database.
+**
+**      Y:   The name of a table in a FROM clause.  Or in a trigger
+**           one of the special names "old" or "new".
+**
+**      Z:   The name of a column in table Y.
+**
+** The node at the root of the subtree is modified as follows:
+**
+**    Expr.op        Changed to TK_COLUMN
+**    Expr.pTab      Points to the Table object for X.Y
+**    Expr.iColumn   The column index in X.Y.  -1 for the rowid.
+**    Expr.iTable    The VDBE cursor number for X.Y
+**
+**
+** To resolve result-set references, look for expression nodes of the
+** form Z (with no X and Y prefix) where the Z matches the right-hand
+** size of an AS clause in the result-set of a SELECT.  The Z expression
+** is replaced by a copy of the left-hand side of the result-set expression.
+** Table-name and function resolution occurs on the substituted expression
+** tree.  For example, in:
+**
+**      SELECT a+b AS x, c+d AS y FROM t1 ORDER BY x;
+**
+** The "x" term of the order by is replaced by "a+b" to render:
+**
+**      SELECT a+b AS x, c+d AS y FROM t1 ORDER BY a+b;
+**
+** Function calls are checked to make sure that the function is
+** defined and that the correct number of arguments are specified.
+** If the function is an aggregate function, then the NC_HasAgg flag is
+** set and the opcode is changed from TK_FUNCTION to TK_AGG_FUNCTION.
+** If an expression contains aggregate functions then the EP_Agg
+** property on the expression is set.
+**
+** An error message is left in pParse if anything is amiss.  The number
+** if errors is returned.
+*/
+SQLITE_PRIVATE int sqlite3ResolveExprNames(
+  NameContext *pNC,       /* Namespace to resolve expressions in. */
+  Expr *pExpr             /* The expression to be analyzed. */
+){
+  int savedHasAgg;
+  Walker w;
+
+  if( pExpr==0 ) return SQLITE_OK;
+  savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+  pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+  w.pParse = pNC->pParse;
+  w.xExprCallback = resolveExprStep;
+  w.xSelectCallback = (pNC->ncFlags & NC_NoSelect) ? 0 : resolveSelectStep;
+  w.xSelectCallback2 = 0;
+  w.u.pNC = pNC;
+#if SQLITE_MAX_EXPR_DEPTH>0
+  w.pParse->nHeight += pExpr->nHeight;
+  if( sqlite3ExprCheckHeight(w.pParse, w.pParse->nHeight) ){
+    return SQLITE_ERROR;
+  }
+#endif
+  assert( pExpr!=0 );
+  sqlite3WalkExprNN(&w, pExpr);
+#if SQLITE_MAX_EXPR_DEPTH>0
+  w.pParse->nHeight -= pExpr->nHeight;
+#endif
+  assert( EP_Agg==NC_HasAgg );
+  assert( EP_Win==NC_HasWin );
+  testcase( pNC->ncFlags & NC_HasAgg );
+  testcase( pNC->ncFlags & NC_HasWin );
+  ExprSetProperty(pExpr, pNC->ncFlags & (NC_HasAgg|NC_HasWin) );
+  pNC->ncFlags |= savedHasAgg;
+  return pNC->nNcErr>0 || w.pParse->nErr>0;
+}
+
+/*
+** Resolve all names for all expression in an expression list.  This is
+** just like sqlite3ResolveExprNames() except that it works for an expression
+** list rather than a single expression.
+**
+** The return value is SQLITE_OK (0) for success or SQLITE_ERROR (1) for a
+** failure.
+*/
+SQLITE_PRIVATE int sqlite3ResolveExprListNames(
+  NameContext *pNC,       /* Namespace to resolve expressions in. */
+  ExprList *pList         /* The expression list to be analyzed. */
+){
+  int i;
+  int savedHasAgg = 0;
+  Walker w;
+  if( pList==0 ) return SQLITE_OK;
+  w.pParse = pNC->pParse;
+  w.xExprCallback = resolveExprStep;
+  w.xSelectCallback = resolveSelectStep;
+  w.xSelectCallback2 = 0;
+  w.u.pNC = pNC;
+  savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+  pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+  for(i=0; i<pList->nExpr; i++){
+    Expr *pExpr = pList->a[i].pExpr;
+    if( pExpr==0 ) continue;
+#if SQLITE_MAX_EXPR_DEPTH>0
+    w.pParse->nHeight += pExpr->nHeight;
+    if( sqlite3ExprCheckHeight(w.pParse, w.pParse->nHeight) ){
+      return SQLITE_ERROR;
+    }
+#endif
+    sqlite3WalkExprNN(&w, pExpr);
+#if SQLITE_MAX_EXPR_DEPTH>0
+    w.pParse->nHeight -= pExpr->nHeight;
+#endif
+    assert( EP_Agg==NC_HasAgg );
+    assert( EP_Win==NC_HasWin );
+    testcase( pNC->ncFlags & NC_HasAgg );
+    testcase( pNC->ncFlags & NC_HasWin );
+    if( pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg) ){
+      ExprSetProperty(pExpr, pNC->ncFlags & (NC_HasAgg|NC_HasWin) );
+      savedHasAgg |= pNC->ncFlags &
+                          (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+      pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
+    }
+    if( w.pParse->nErr>0 ) return SQLITE_ERROR;
+  }
+  pNC->ncFlags |= savedHasAgg;
+  return SQLITE_OK;
+}
+
+/*
+** Resolve all names in all expressions of a SELECT and in all
+** descendants of the SELECT, including compounds off of p->pPrior,
+** subqueries in expressions, and subqueries used as FROM clause
+** terms.
+**
+** See sqlite3ResolveExprNames() for a description of the kinds of
+** transformations that occur.
+**
+** All SELECT statements should have been expanded using
+** sqlite3SelectExpand() prior to invoking this routine.
+*/
+SQLITE_PRIVATE void sqlite3ResolveSelectNames(
+  Parse *pParse,         /* The parser context */
+  Select *p,             /* The SELECT statement being coded. */
+  NameContext *pOuterNC  /* Name context for parent SELECT statement */
+){
+  Walker w;
+
+  assert( p!=0 );
+  w.xExprCallback = resolveExprStep;
+  w.xSelectCallback = resolveSelectStep;
+  w.xSelectCallback2 = 0;
+  w.pParse = pParse;
+  w.u.pNC = pOuterNC;
+  sqlite3WalkSelect(&w, p);
+}
+
+/*
+** Resolve names in expressions that can only reference a single table
+** or which cannot reference any tables at all.  Examples:
+**
+**                                                    "type" flag
+**                                                    ------------
+**    (1)   CHECK constraints                         NC_IsCheck
+**    (2)   WHERE clauses on partial indices          NC_PartIdx
+**    (3)   Expressions in indexes on expressions     NC_IdxExpr
+**    (4)   Expression arguments to VACUUM INTO.      0
+**    (5)   GENERATED ALWAYS as expressions           NC_GenCol
+**
+** In all cases except (4), the Expr.iTable value for Expr.op==TK_COLUMN
+** nodes of the expression is set to -1 and the Expr.iColumn value is
+** set to the column number.  In case (4), TK_COLUMN nodes cause an error.
+**
+** Any errors cause an error message to be set in pParse.
+*/
+SQLITE_PRIVATE int sqlite3ResolveSelfReference(
+  Parse *pParse,   /* Parsing context */
+  Table *pTab,     /* The table being referenced, or NULL */
+  int type,        /* NC_IsCheck, NC_PartIdx, NC_IdxExpr, NC_GenCol, or 0 */
+  Expr *pExpr,     /* Expression to resolve.  May be NULL. */
+  ExprList *pList  /* Expression list to resolve.  May be NULL. */
+){
+  SrcList sSrc;                   /* Fake SrcList for pParse->pNewTable */
+  NameContext sNC;                /* Name context for pParse->pNewTable */
+  int rc;
+
+  assert( type==0 || pTab!=0 );
+  assert( type==NC_IsCheck || type==NC_PartIdx || type==NC_IdxExpr
+          || type==NC_GenCol || pTab==0 );
+  memset(&sNC, 0, sizeof(sNC));
+  memset(&sSrc, 0, sizeof(sSrc));
+  if( pTab ){
+    sSrc.nSrc = 1;
+    sSrc.a[0].zName = pTab->zName;
+    sSrc.a[0].pSTab = pTab;
+    sSrc.a[0].iCursor = -1;
+    if( pTab->pSchema!=pParse->db->aDb[1].pSchema ){
+      /* Cause EP_FromDDL to be set on TK_FUNCTION nodes of non-TEMP
+      ** schema elements */
+      type |= NC_FromDDL;
+    }
+  }
+  sNC.pParse = pParse;
+  sNC.pSrcList = &sSrc;
+  sNC.ncFlags = type | NC_IsDDL;
+  if( (rc = sqlite3ResolveExprNames(&sNC, pExpr))!=SQLITE_OK ) return rc;
+  if( pList ) rc = sqlite3ResolveExprListNames(&sNC, pList);
+  return rc;
+}
+
+/************** End of resolve.c *********************************************/
+/************** Begin file expr.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains routines used for analyzing expressions and
+** for generating VDBE code that evaluates expressions in SQLite.
+*/
+/* #include "sqliteInt.h" */
+
+/* Forward declarations */
+static void exprCodeBetween(Parse*,Expr*,int,void(*)(Parse*,Expr*,int,int),int);
+static int exprCodeVector(Parse *pParse, Expr *p, int *piToFree);
+
+/*
+** Return the affinity character for a single column of a table.
+*/
+SQLITE_PRIVATE char sqlite3TableColumnAffinity(const Table *pTab, int iCol){
+  if( iCol<0 || NEVER(iCol>=pTab->nCol) ) return SQLITE_AFF_INTEGER;
+  return pTab->aCol[iCol].affinity;
+}
+
+/*
+** Return the 'affinity' of the expression pExpr if any.
+**
+** If pExpr is a column, a reference to a column via an 'AS' alias,
+** or a sub-select with a column as the return value, then the
+** affinity of that column is returned. Otherwise, 0x00 is returned,
+** indicating no affinity for the expression.
+**
+** i.e. the WHERE clause expressions in the following statements all
+** have an affinity:
+**
+** CREATE TABLE t1(a);
+** SELECT * FROM t1 WHERE a;
+** SELECT a AS b FROM t1 WHERE b;
+** SELECT * FROM t1 WHERE (select a from t1);
+*/
+SQLITE_PRIVATE char sqlite3ExprAffinity(const Expr *pExpr){
+  int op;
+  op = pExpr->op;
+  while( 1 /* exit-by-break */ ){
+    if( op==TK_COLUMN || (op==TK_AGG_COLUMN && pExpr->y.pTab!=0) ){
+      assert( ExprUseYTab(pExpr) );
+      assert( pExpr->y.pTab!=0 );
+      return sqlite3TableColumnAffinity(pExpr->y.pTab, pExpr->iColumn);
+    }
+    if( op==TK_SELECT ){
+      assert( ExprUseXSelect(pExpr) );
+      assert( pExpr->x.pSelect!=0 );
+      assert( pExpr->x.pSelect->pEList!=0 );
+      assert( pExpr->x.pSelect->pEList->a[0].pExpr!=0 );
+      return sqlite3ExprAffinity(pExpr->x.pSelect->pEList->a[0].pExpr);
+    }
+#ifndef SQLITE_OMIT_CAST
+    if( op==TK_CAST ){
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      return sqlite3AffinityType(pExpr->u.zToken, 0);
+    }
+#endif
+    if( op==TK_SELECT_COLUMN ){
+      assert( pExpr->pLeft!=0 && ExprUseXSelect(pExpr->pLeft) );
+      assert( pExpr->iColumn < pExpr->iTable );
+      assert( pExpr->iColumn >= 0 );
+      assert( pExpr->iTable==pExpr->pLeft->x.pSelect->pEList->nExpr );
+      return sqlite3ExprAffinity(
+          pExpr->pLeft->x.pSelect->pEList->a[pExpr->iColumn].pExpr
+      );
+    }
+    if( op==TK_VECTOR ){
+      assert( ExprUseXList(pExpr) );
+      return sqlite3ExprAffinity(pExpr->x.pList->a[0].pExpr);
+    }
+    if( ExprHasProperty(pExpr, EP_Skip|EP_IfNullRow) ){
+      assert( pExpr->op==TK_COLLATE
+           || pExpr->op==TK_IF_NULL_ROW
+           || (pExpr->op==TK_REGISTER && pExpr->op2==TK_IF_NULL_ROW) );
+      pExpr = pExpr->pLeft;
+      op = pExpr->op;
+      continue;
+    }
+    if( op!=TK_REGISTER ) break;
+    op = pExpr->op2;
+    if( NEVER( op==TK_REGISTER ) ) break;
+  }
+  return pExpr->affExpr;
+}
+
+/*
+** Make a guess at all the possible datatypes of the result that could
+** be returned by an expression.  Return a bitmask indicating the answer:
+**
+**     0x01         Numeric
+**     0x02         Text
+**     0x04         Blob
+**
+** If the expression must return NULL, then 0x00 is returned.
+*/
+SQLITE_PRIVATE int sqlite3ExprDataType(const Expr *pExpr){
+  while( pExpr ){
+    switch( pExpr->op ){
+      case TK_COLLATE:
+      case TK_IF_NULL_ROW:
+      case TK_UPLUS:  {
+        pExpr = pExpr->pLeft;
+        break;
+      }
+      case TK_NULL: {
+        pExpr = 0;
+        break;
+      }
+      case TK_STRING: {
+        return 0x02;
+      }
+      case TK_BLOB: {
+        return 0x04;
+      }
+      case TK_CONCAT: {
+        return 0x06;
+      }
+      case TK_VARIABLE:
+      case TK_AGG_FUNCTION:
+      case TK_FUNCTION: {
+        return 0x07;
+      }
+      case TK_COLUMN:
+      case TK_AGG_COLUMN:
+      case TK_SELECT:
+      case TK_CAST:
+      case TK_SELECT_COLUMN:
+      case TK_VECTOR:  {
+        int aff = sqlite3ExprAffinity(pExpr);
+        if( aff>=SQLITE_AFF_NUMERIC ) return 0x05;
+        if( aff==SQLITE_AFF_TEXT )    return 0x06;
+        return 0x07;
+      }
+      case TK_CASE: {
+        int res = 0;
+        int ii;
+        ExprList *pList = pExpr->x.pList;
+        assert( ExprUseXList(pExpr) && pList!=0 );
+        assert( pList->nExpr > 0);
+        for(ii=1; ii<pList->nExpr; ii+=2){
+          res |= sqlite3ExprDataType(pList->a[ii].pExpr);
+        }
+        if( pList->nExpr % 2 ){
+          res |= sqlite3ExprDataType(pList->a[pList->nExpr-1].pExpr);
+        }
+        return res;
+      }
+      default: {
+        return 0x01;
+      }
+    } /* End of switch(op) */
+  } /* End of while(pExpr) */
+  return 0x00;
+}
+
+/*
+** Set the collating sequence for expression pExpr to be the collating
+** sequence named by pToken.   Return a pointer to a new Expr node that
+** implements the COLLATE operator.
+**
+** If a memory allocation error occurs, that fact is recorded in pParse->db
+** and the pExpr parameter is returned unchanged.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprAddCollateToken(
+  const Parse *pParse,     /* Parsing context */
+  Expr *pExpr,             /* Add the "COLLATE" clause to this expression */
+  const Token *pCollName,  /* Name of collating sequence */
+  int dequote              /* True to dequote pCollName */
+){
+  if( pCollName->n>0 ){
+    Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLLATE, pCollName, dequote);
+    if( pNew ){
+      pNew->pLeft = pExpr;
+      pNew->flags |= EP_Collate|EP_Skip;
+      pExpr = pNew;
+    }
+  }
+  return pExpr;
+}
+SQLITE_PRIVATE Expr *sqlite3ExprAddCollateString(
+  const Parse *pParse,  /* Parsing context */
+  Expr *pExpr,          /* Add the "COLLATE" clause to this expression */
+  const char *zC        /* The collating sequence name */
+){
+  Token s;
+  assert( zC!=0 );
+  sqlite3TokenInit(&s, (char*)zC);
+  return sqlite3ExprAddCollateToken(pParse, pExpr, &s, 0);
+}
+
+/*
+** Skip over any TK_COLLATE operators.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprSkipCollate(Expr *pExpr){
+  while( pExpr && ExprHasProperty(pExpr, EP_Skip) ){
+    assert( pExpr->op==TK_COLLATE );
+    pExpr = pExpr->pLeft;
+  }
+  return pExpr;
+}
+
+/*
+** Skip over any TK_COLLATE operators and/or any unlikely()
+** or likelihood() or likely() functions at the root of an
+** expression.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprSkipCollateAndLikely(Expr *pExpr){
+  while( pExpr && ExprHasProperty(pExpr, EP_Skip|EP_Unlikely) ){
+    if( ExprHasProperty(pExpr, EP_Unlikely) ){
+      assert( ExprUseXList(pExpr) );
+      assert( pExpr->x.pList->nExpr>0 );
+      assert( pExpr->op==TK_FUNCTION );
+      pExpr = pExpr->x.pList->a[0].pExpr;
+    }else if( pExpr->op==TK_COLLATE ){
+      pExpr = pExpr->pLeft;
+    }else{
+      break;
+    }
+  }
+  return pExpr;
+}
+
+/*
+** Return the collation sequence for the expression pExpr. If
+** there is no defined collating sequence, return NULL.
+**
+** See also: sqlite3ExprNNCollSeq()
+**
+** The sqlite3ExprNNCollSeq() works the same exact that it returns the
+** default collation if pExpr has no defined collation.
+**
+** The collating sequence might be determined by a COLLATE operator
+** or by the presence of a column with a defined collating sequence.
+** COLLATE operators take first precedence.  Left operands take
+** precedence over right operands.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, const Expr *pExpr){
+  sqlite3 *db = pParse->db;
+  CollSeq *pColl = 0;
+  const Expr *p = pExpr;
+  while( p ){
+    int op = p->op;
+    if( op==TK_REGISTER ) op = p->op2;
+    if( (op==TK_AGG_COLUMN && p->y.pTab!=0)
+     || op==TK_COLUMN || op==TK_TRIGGER
+    ){
+      int j;
+      assert( ExprUseYTab(p) );
+      assert( p->y.pTab!=0 );
+      if( (j = p->iColumn)>=0 ){
+        const char *zColl = sqlite3ColumnColl(&p->y.pTab->aCol[j]);
+        pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);
+      }
+      break;
+    }
+    if( op==TK_CAST || op==TK_UPLUS ){
+      p = p->pLeft;
+      continue;
+    }
+    if( op==TK_VECTOR ){
+      assert( ExprUseXList(p) );
+      p = p->x.pList->a[0].pExpr;
+      continue;
+    }
+    if( op==TK_COLLATE ){
+      assert( !ExprHasProperty(p, EP_IntValue) );
+      pColl = sqlite3GetCollSeq(pParse, ENC(db), 0, p->u.zToken);
+      break;
+    }
+    if( p->flags & EP_Collate ){
+      if( p->pLeft && (p->pLeft->flags & EP_Collate)!=0 ){
+        p = p->pLeft;
+      }else{
+        Expr *pNext  = p->pRight;
+        /* The Expr.x union is never used at the same time as Expr.pRight */
+        assert( !ExprUseXList(p) || p->x.pList==0 || p->pRight==0 );
+        if( ExprUseXList(p) && p->x.pList!=0 && !db->mallocFailed ){
+          int i;
+          for(i=0; i<p->x.pList->nExpr; i++){
+            if( ExprHasProperty(p->x.pList->a[i].pExpr, EP_Collate) ){
+              pNext = p->x.pList->a[i].pExpr;
+              break;
+            }
+          }
+        }
+        p = pNext;
+      }
+    }else{
+      break;
+    }
+  }
+  if( sqlite3CheckCollSeq(pParse, pColl) ){
+    pColl = 0;
+  }
+  return pColl;
+}
+
+/*
+** Return the collation sequence for the expression pExpr. If
+** there is no defined collating sequence, return a pointer to the
+** default collation sequence.
+**
+** See also: sqlite3ExprCollSeq()
+**
+** The sqlite3ExprCollSeq() routine works the same except that it
+** returns NULL if there is no defined collation.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3ExprNNCollSeq(Parse *pParse, const Expr *pExpr){
+  CollSeq *p = sqlite3ExprCollSeq(pParse, pExpr);
+  if( p==0 ) p = pParse->db->pDfltColl;
+  assert( p!=0 );
+  return p;
+}
+
+/*
+** Return TRUE if the two expressions have equivalent collating sequences.
+*/
+SQLITE_PRIVATE int sqlite3ExprCollSeqMatch(Parse *pParse, const Expr *pE1, const Expr *pE2){
+  CollSeq *pColl1 = sqlite3ExprNNCollSeq(pParse, pE1);
+  CollSeq *pColl2 = sqlite3ExprNNCollSeq(pParse, pE2);
+  return sqlite3StrICmp(pColl1->zName, pColl2->zName)==0;
+}
+
+/*
+** pExpr is an operand of a comparison operator.  aff2 is the
+** type affinity of the other operand.  This routine returns the
+** type affinity that should be used for the comparison operator.
+*/
+SQLITE_PRIVATE char sqlite3CompareAffinity(const Expr *pExpr, char aff2){
+  char aff1 = sqlite3ExprAffinity(pExpr);
+  if( aff1>SQLITE_AFF_NONE && aff2>SQLITE_AFF_NONE ){
+    /* Both sides of the comparison are columns. If one has numeric
+    ** affinity, use that. Otherwise use no affinity.
+    */
+    if( sqlite3IsNumericAffinity(aff1) || sqlite3IsNumericAffinity(aff2) ){
+      return SQLITE_AFF_NUMERIC;
+    }else{
+      return SQLITE_AFF_BLOB;
+    }
+  }else{
+    /* One side is a column, the other is not. Use the columns affinity. */
+    assert( aff1<=SQLITE_AFF_NONE || aff2<=SQLITE_AFF_NONE );
+    return (aff1<=SQLITE_AFF_NONE ? aff2 : aff1) | SQLITE_AFF_NONE;
+  }
+}
+
+/*
+** pExpr is a comparison operator.  Return the type affinity that should
+** be applied to both operands prior to doing the comparison.
+*/
+static char comparisonAffinity(const Expr *pExpr){
+  char aff;
+  assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
+          pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
+          pExpr->op==TK_NE || pExpr->op==TK_IS || pExpr->op==TK_ISNOT );
+  assert( pExpr->pLeft );
+  aff = sqlite3ExprAffinity(pExpr->pLeft);
+  if( pExpr->pRight ){
+    aff = sqlite3CompareAffinity(pExpr->pRight, aff);
+  }else if( ExprUseXSelect(pExpr) ){
+    aff = sqlite3CompareAffinity(pExpr->x.pSelect->pEList->a[0].pExpr, aff);
+  }else if( aff==0 ){
+    aff = SQLITE_AFF_BLOB;
+  }
+  return aff;
+}
+
+/*
+** pExpr is a comparison expression, eg. '=', '<', IN(...) etc.
+** idx_affinity is the affinity of an indexed column. Return true
+** if the index with affinity idx_affinity may be used to implement
+** the comparison in pExpr.
+*/
+SQLITE_PRIVATE int sqlite3IndexAffinityOk(const Expr *pExpr, char idx_affinity){
+  char aff = comparisonAffinity(pExpr);
+  if( aff<SQLITE_AFF_TEXT ){
+    return 1;
+  }
+  if( aff==SQLITE_AFF_TEXT ){
+    return idx_affinity==SQLITE_AFF_TEXT;
+  }
+  return sqlite3IsNumericAffinity(idx_affinity);
+}
+
+/*
+** Return the P5 value that should be used for a binary comparison
+** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.
+*/
+static u8 binaryCompareP5(
+  const Expr *pExpr1,   /* Left operand */
+  const Expr *pExpr2,   /* Right operand */
+  int jumpIfNull        /* Extra flags added to P5 */
+){
+  u8 aff = (char)sqlite3ExprAffinity(pExpr2);
+  aff = (u8)sqlite3CompareAffinity(pExpr1, aff) | (u8)jumpIfNull;
+  return aff;
+}
+
+/*
+** Return a pointer to the collation sequence that should be used by
+** a binary comparison operator comparing pLeft and pRight.
+**
+** If the left hand expression has a collating sequence type, then it is
+** used. Otherwise the collation sequence for the right hand expression
+** is used, or the default (BINARY) if neither expression has a collating
+** type.
+**
+** Argument pRight (but not pLeft) may be a null pointer. In this case,
+** it is not considered.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3BinaryCompareCollSeq(
+  Parse *pParse,
+  const Expr *pLeft,
+  const Expr *pRight
+){
+  CollSeq *pColl;
+  assert( pLeft );
+  if( pLeft->flags & EP_Collate ){
+    pColl = sqlite3ExprCollSeq(pParse, pLeft);
+  }else if( pRight && (pRight->flags & EP_Collate)!=0 ){
+    pColl = sqlite3ExprCollSeq(pParse, pRight);
+  }else{
+    pColl = sqlite3ExprCollSeq(pParse, pLeft);
+    if( !pColl ){
+      pColl = sqlite3ExprCollSeq(pParse, pRight);
+    }
+  }
+  return pColl;
+}
+
+/* Expression p is a comparison operator.  Return a collation sequence
+** appropriate for the comparison operator.
+**
+** This is normally just a wrapper around sqlite3BinaryCompareCollSeq().
+** However, if the OP_Commuted flag is set, then the order of the operands
+** is reversed in the sqlite3BinaryCompareCollSeq() call so that the
+** correct collating sequence is found.
+*/
+SQLITE_PRIVATE CollSeq *sqlite3ExprCompareCollSeq(Parse *pParse, const Expr *p){
+  if( ExprHasProperty(p, EP_Commuted) ){
+    return sqlite3BinaryCompareCollSeq(pParse, p->pRight, p->pLeft);
+  }else{
+    return sqlite3BinaryCompareCollSeq(pParse, p->pLeft, p->pRight);
+  }
+}
+
+/*
+** Generate code for a comparison operator.
+*/
+static int codeCompare(
+  Parse *pParse,    /* The parsing (and code generating) context */
+  Expr *pLeft,      /* The left operand */
+  Expr *pRight,     /* The right operand */
+  int opcode,       /* The comparison opcode */
+  int in1, int in2, /* Register holding operands */
+  int dest,         /* Jump here if true.  */
+  int jumpIfNull,   /* If true, jump if either operand is NULL */
+  int isCommuted    /* The comparison has been commuted */
+){
+  int p5;
+  int addr;
+  CollSeq *p4;
+
+  if( pParse->nErr ) return 0;
+  if( isCommuted ){
+    p4 = sqlite3BinaryCompareCollSeq(pParse, pRight, pLeft);
+  }else{
+    p4 = sqlite3BinaryCompareCollSeq(pParse, pLeft, pRight);
+  }
+  p5 = binaryCompareP5(pLeft, pRight, jumpIfNull);
+  addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
+                           (void*)p4, P4_COLLSEQ);
+  sqlite3VdbeChangeP5(pParse->pVdbe, (u16)p5);
+  return addr;
+}
+
+/*
+** Return true if expression pExpr is a vector, or false otherwise.
+**
+** A vector is defined as any expression that results in two or more
+** columns of result.  Every TK_VECTOR node is an vector because the
+** parser will not generate a TK_VECTOR with fewer than two entries.
+** But a TK_SELECT might be either a vector or a scalar. It is only
+** considered a vector if it has two or more result columns.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsVector(const Expr *pExpr){
+  return sqlite3ExprVectorSize(pExpr)>1;
+}
+
+/*
+** If the expression passed as the only argument is of type TK_VECTOR
+** return the number of expressions in the vector. Or, if the expression
+** is a sub-select, return the number of columns in the sub-select. For
+** any other type of expression, return 1.
+*/
+SQLITE_PRIVATE int sqlite3ExprVectorSize(const Expr *pExpr){
+  u8 op = pExpr->op;
+  if( op==TK_REGISTER ) op = pExpr->op2;
+  if( op==TK_VECTOR ){
+    assert( ExprUseXList(pExpr) );
+    return pExpr->x.pList->nExpr;
+  }else if( op==TK_SELECT ){
+    assert( ExprUseXSelect(pExpr) );
+    return pExpr->x.pSelect->pEList->nExpr;
+  }else{
+    return 1;
+  }
+}
+
+/*
+** Return a pointer to a subexpression of pVector that is the i-th
+** column of the vector (numbered starting with 0).  The caller must
+** ensure that i is within range.
+**
+** If pVector is really a scalar (and "scalar" here includes subqueries
+** that return a single column!) then return pVector unmodified.
+**
+** pVector retains ownership of the returned subexpression.
+**
+** If the vector is a (SELECT ...) then the expression returned is
+** just the expression for the i-th term of the result set, and may
+** not be ready for evaluation because the table cursor has not yet
+** been positioned.
+*/
+SQLITE_PRIVATE Expr *sqlite3VectorFieldSubexpr(Expr *pVector, int i){
+  assert( i<sqlite3ExprVectorSize(pVector) || pVector->op==TK_ERROR );
+  if( sqlite3ExprIsVector(pVector) ){
+    assert( pVector->op2==0 || pVector->op==TK_REGISTER );
+    if( pVector->op==TK_SELECT || pVector->op2==TK_SELECT ){
+      assert( ExprUseXSelect(pVector) );
+      return pVector->x.pSelect->pEList->a[i].pExpr;
+    }else{
+      assert( ExprUseXList(pVector) );
+      return pVector->x.pList->a[i].pExpr;
+    }
+  }
+  return pVector;
+}
+
+/*
+** Compute and return a new Expr object which when passed to
+** sqlite3ExprCode() will generate all necessary code to compute
+** the iField-th column of the vector expression pVector.
+**
+** It is ok for pVector to be a scalar (as long as iField==0).
+** In that case, this routine works like sqlite3ExprDup().
+**
+** The caller owns the returned Expr object and is responsible for
+** ensuring that the returned value eventually gets freed.
+**
+** The caller retains ownership of pVector.  If pVector is a TK_SELECT,
+** then the returned object will reference pVector and so pVector must remain
+** valid for the life of the returned object.  If pVector is a TK_VECTOR
+** or a scalar expression, then it can be deleted as soon as this routine
+** returns.
+**
+** A trick to cause a TK_SELECT pVector to be deleted together with
+** the returned Expr object is to attach the pVector to the pRight field
+** of the returned TK_SELECT_COLUMN Expr object.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprForVectorField(
+  Parse *pParse,       /* Parsing context */
+  Expr *pVector,       /* The vector.  List of expressions or a sub-SELECT */
+  int iField,          /* Which column of the vector to return */
+  int nField           /* Total number of columns in the vector */
+){
+  Expr *pRet;
+  if( pVector->op==TK_SELECT ){
+    assert( ExprUseXSelect(pVector) );
+    /* The TK_SELECT_COLUMN Expr node:
+    **
+    ** pLeft:           pVector containing TK_SELECT.  Not deleted.
+    ** pRight:          not used.  But recursively deleted.
+    ** iColumn:         Index of a column in pVector
+    ** iTable:          0 or the number of columns on the LHS of an assignment
+    ** pLeft->iTable:   First in an array of register holding result, or 0
+    **                  if the result is not yet computed.
+    **
+    ** sqlite3ExprDelete() specifically skips the recursive delete of
+    ** pLeft on TK_SELECT_COLUMN nodes.  But pRight is followed, so pVector
+    ** can be attached to pRight to cause this node to take ownership of
+    ** pVector.  Typically there will be multiple TK_SELECT_COLUMN nodes
+    ** with the same pLeft pointer to the pVector, but only one of them
+    ** will own the pVector.
+    */
+    pRet = sqlite3PExpr(pParse, TK_SELECT_COLUMN, 0, 0);
+    if( pRet ){
+      ExprSetProperty(pRet, EP_FullSize);
+      pRet->iTable = nField;
+      pRet->iColumn = iField;
+      pRet->pLeft = pVector;
+    }
+  }else{
+    if( pVector->op==TK_VECTOR ){
+      Expr **ppVector;
+      assert( ExprUseXList(pVector) );
+      ppVector = &pVector->x.pList->a[iField].pExpr;
+      pVector = *ppVector;
+      if( IN_RENAME_OBJECT ){
+        /* This must be a vector UPDATE inside a trigger */
+        *ppVector = 0;
+        return pVector;
+      }
+    }
+    pRet = sqlite3ExprDup(pParse->db, pVector, 0);
+  }
+  return pRet;
+}
+
+/*
+** If expression pExpr is of type TK_SELECT, generate code to evaluate
+** it. Return the register in which the result is stored (or, if the
+** sub-select returns more than one column, the first in an array
+** of registers in which the result is stored).
+**
+** If pExpr is not a TK_SELECT expression, return 0.
+*/
+static int exprCodeSubselect(Parse *pParse, Expr *pExpr){
+  int reg = 0;
+#ifndef SQLITE_OMIT_SUBQUERY
+  if( pExpr->op==TK_SELECT ){
+    reg = sqlite3CodeSubselect(pParse, pExpr);
+  }
+#endif
+  return reg;
+}
+
+/*
+** Argument pVector points to a vector expression - either a TK_VECTOR
+** or TK_SELECT that returns more than one column. This function returns
+** the register number of a register that contains the value of
+** element iField of the vector.
+**
+** If pVector is a TK_SELECT expression, then code for it must have
+** already been generated using the exprCodeSubselect() routine. In this
+** case parameter regSelect should be the first in an array of registers
+** containing the results of the sub-select.
+**
+** If pVector is of type TK_VECTOR, then code for the requested field
+** is generated. In this case (*pRegFree) may be set to the number of
+** a temporary register to be freed by the caller before returning.
+**
+** Before returning, output parameter (*ppExpr) is set to point to the
+** Expr object corresponding to element iElem of the vector.
+*/
+static int exprVectorRegister(
+  Parse *pParse,                  /* Parse context */
+  Expr *pVector,                  /* Vector to extract element from */
+  int iField,                     /* Field to extract from pVector */
+  int regSelect,                  /* First in array of registers */
+  Expr **ppExpr,                  /* OUT: Expression element */
+  int *pRegFree                   /* OUT: Temp register to free */
+){
+  u8 op = pVector->op;
+  assert( op==TK_VECTOR || op==TK_REGISTER || op==TK_SELECT || op==TK_ERROR );
+  if( op==TK_REGISTER ){
+    *ppExpr = sqlite3VectorFieldSubexpr(pVector, iField);
+    return pVector->iTable+iField;
+  }
+  if( op==TK_SELECT ){
+    assert( ExprUseXSelect(pVector) );
+    *ppExpr = pVector->x.pSelect->pEList->a[iField].pExpr;
+     return regSelect+iField;
+  }
+  if( op==TK_VECTOR ){
+    assert( ExprUseXList(pVector) );
+    *ppExpr = pVector->x.pList->a[iField].pExpr;
+    return sqlite3ExprCodeTemp(pParse, *ppExpr, pRegFree);
+  }
+  return 0;
+}
+
+/*
+** Expression pExpr is a comparison between two vector values. Compute
+** the result of the comparison (1, 0, or NULL) and write that
+** result into register dest.
+**
+** The caller must satisfy the following preconditions:
+**
+**    if pExpr->op==TK_IS:      op==TK_EQ and p5==SQLITE_NULLEQ
+**    if pExpr->op==TK_ISNOT:   op==TK_NE and p5==SQLITE_NULLEQ
+**    otherwise:                op==pExpr->op and p5==0
+*/
+static void codeVectorCompare(
+  Parse *pParse,        /* Code generator context */
+  Expr *pExpr,          /* The comparison operation */
+  int dest,             /* Write results into this register */
+  u8 op,                /* Comparison operator */
+  u8 p5                 /* SQLITE_NULLEQ or zero */
+){
+  Vdbe *v = pParse->pVdbe;
+  Expr *pLeft = pExpr->pLeft;
+  Expr *pRight = pExpr->pRight;
+  int nLeft = sqlite3ExprVectorSize(pLeft);
+  int i;
+  int regLeft = 0;
+  int regRight = 0;
+  u8 opx = op;
+  int addrCmp = 0;
+  int addrDone = sqlite3VdbeMakeLabel(pParse);
+  int isCommuted = ExprHasProperty(pExpr,EP_Commuted);
+
+  assert( !ExprHasVVAProperty(pExpr,EP_Immutable) );
+  if( pParse->nErr ) return;
+  if( nLeft!=sqlite3ExprVectorSize(pRight) ){
+    sqlite3ErrorMsg(pParse, "row value misused");
+    return;
+  }
+  assert( pExpr->op==TK_EQ || pExpr->op==TK_NE
+       || pExpr->op==TK_IS || pExpr->op==TK_ISNOT
+       || pExpr->op==TK_LT || pExpr->op==TK_GT
+       || pExpr->op==TK_LE || pExpr->op==TK_GE
+  );
+  assert( pExpr->op==op || (pExpr->op==TK_IS && op==TK_EQ)
+            || (pExpr->op==TK_ISNOT && op==TK_NE) );
+  assert( p5==0 || pExpr->op!=op );
+  assert( p5==SQLITE_NULLEQ || pExpr->op==op );
+
+  if( op==TK_LE ) opx = TK_LT;
+  if( op==TK_GE ) opx = TK_GT;
+  if( op==TK_NE ) opx = TK_EQ;
+
+  regLeft = exprCodeSubselect(pParse, pLeft);
+  regRight = exprCodeSubselect(pParse, pRight);
+
+  sqlite3VdbeAddOp2(v, OP_Integer, 1, dest);
+  for(i=0; 1 /*Loop exits by "break"*/; i++){
+    int regFree1 = 0, regFree2 = 0;
+    Expr *pL = 0, *pR = 0;
+    int r1, r2;
+    assert( i>=0 && i<nLeft );
+    if( addrCmp ) sqlite3VdbeJumpHere(v, addrCmp);
+    r1 = exprVectorRegister(pParse, pLeft, i, regLeft, &pL, ®Free1);
+    r2 = exprVectorRegister(pParse, pRight, i, regRight, &pR, ®Free2);
+    addrCmp = sqlite3VdbeCurrentAddr(v);
+    codeCompare(pParse, pL, pR, opx, r1, r2, addrDone, p5, isCommuted);
+    testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+    testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+    testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+    testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+    testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
+    testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
+    sqlite3ReleaseTempReg(pParse, regFree1);
+    sqlite3ReleaseTempReg(pParse, regFree2);
+    if( (opx==TK_LT || opx==TK_GT) && i<nLeft-1 ){
+      addrCmp = sqlite3VdbeAddOp0(v, OP_ElseEq);
+      testcase(opx==TK_LT); VdbeCoverageIf(v,opx==TK_LT);
+      testcase(opx==TK_GT); VdbeCoverageIf(v,opx==TK_GT);
+    }
+    if( p5==SQLITE_NULLEQ ){
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, dest);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_ZeroOrNull, r1, dest, r2);
+    }
+    if( i==nLeft-1 ){
+      break;
+    }
+    if( opx==TK_EQ ){
+      sqlite3VdbeAddOp2(v, OP_NotNull, dest, addrDone); VdbeCoverage(v);
+    }else{
+      assert( op==TK_LT || op==TK_GT || op==TK_LE || op==TK_GE );
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrDone);
+      if( i==nLeft-2 ) opx = op;
+    }
+  }
+  sqlite3VdbeJumpHere(v, addrCmp);
+  sqlite3VdbeResolveLabel(v, addrDone);
+  if( op==TK_NE ){
+    sqlite3VdbeAddOp2(v, OP_Not, dest, dest);
+  }
+}
+
+#if SQLITE_MAX_EXPR_DEPTH>0
+/*
+** Check that argument nHeight is less than or equal to the maximum
+** expression depth allowed. If it is not, leave an error message in
+** pParse.
+*/
+SQLITE_PRIVATE int sqlite3ExprCheckHeight(Parse *pParse, int nHeight){
+  int rc = SQLITE_OK;
+  int mxHeight = pParse->db->aLimit[SQLITE_LIMIT_EXPR_DEPTH];
+  if( nHeight>mxHeight ){
+    sqlite3ErrorMsg(pParse,
+       "Expression tree is too large (maximum depth %d)", mxHeight
+    );
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/* The following three functions, heightOfExpr(), heightOfExprList()
+** and heightOfSelect(), are used to determine the maximum height
+** of any expression tree referenced by the structure passed as the
+** first argument.
+**
+** If this maximum height is greater than the current value pointed
+** to by pnHeight, the second parameter, then set *pnHeight to that
+** value.
+*/
+static void heightOfExpr(const Expr *p, int *pnHeight){
+  if( p ){
+    if( p->nHeight>*pnHeight ){
+      *pnHeight = p->nHeight;
+    }
+  }
+}
+static void heightOfExprList(const ExprList *p, int *pnHeight){
+  if( p ){
+    int i;
+    for(i=0; i<p->nExpr; i++){
+      heightOfExpr(p->a[i].pExpr, pnHeight);
+    }
+  }
+}
+static void heightOfSelect(const Select *pSelect, int *pnHeight){
+  const Select *p;
+  for(p=pSelect; p; p=p->pPrior){
+    heightOfExpr(p->pWhere, pnHeight);
+    heightOfExpr(p->pHaving, pnHeight);
+    heightOfExpr(p->pLimit, pnHeight);
+    heightOfExprList(p->pEList, pnHeight);
+    heightOfExprList(p->pGroupBy, pnHeight);
+    heightOfExprList(p->pOrderBy, pnHeight);
+  }
+}
+
+/*
+** Set the Expr.nHeight variable in the structure passed as an
+** argument. An expression with no children, Expr.pList or
+** Expr.pSelect member has a height of 1. Any other expression
+** has a height equal to the maximum height of any other
+** referenced Expr plus one.
+**
+** Also propagate EP_Propagate flags up from Expr.x.pList to Expr.flags,
+** if appropriate.
+*/
+static void exprSetHeight(Expr *p){
+  int nHeight = p->pLeft ? p->pLeft->nHeight : 0;
+  if( NEVER(p->pRight) && p->pRight->nHeight>nHeight ){
+    nHeight = p->pRight->nHeight;
+  }
+  if( ExprUseXSelect(p) ){
+    heightOfSelect(p->x.pSelect, &nHeight);
+  }else if( p->x.pList ){
+    heightOfExprList(p->x.pList, &nHeight);
+    p->flags |= EP_Propagate & sqlite3ExprListFlags(p->x.pList);
+  }
+  p->nHeight = nHeight + 1;
+}
+
+/*
+** Set the Expr.nHeight variable using the exprSetHeight() function. If
+** the height is greater than the maximum allowed expression depth,
+** leave an error in pParse.
+**
+** Also propagate all EP_Propagate flags from the Expr.x.pList into
+** Expr.flags.
+*/
+SQLITE_PRIVATE void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p){
+  if( pParse->nErr ) return;
+  exprSetHeight(p);
+  sqlite3ExprCheckHeight(pParse, p->nHeight);
+}
+
+/*
+** Return the maximum height of any expression tree referenced
+** by the select statement passed as an argument.
+*/
+SQLITE_PRIVATE int sqlite3SelectExprHeight(const Select *p){
+  int nHeight = 0;
+  heightOfSelect(p, &nHeight);
+  return nHeight;
+}
+#else /* ABOVE:  Height enforcement enabled.  BELOW: Height enforcement off */
+/*
+** Propagate all EP_Propagate flags from the Expr.x.pList into
+** Expr.flags.
+*/
+SQLITE_PRIVATE void sqlite3ExprSetHeightAndFlags(Parse *pParse, Expr *p){
+  if( pParse->nErr ) return;
+  if( p && ExprUseXList(p) && p->x.pList ){
+    p->flags |= EP_Propagate & sqlite3ExprListFlags(p->x.pList);
+  }
+}
+#define exprSetHeight(y)
+#endif /* SQLITE_MAX_EXPR_DEPTH>0 */
+
+/*
+** Set the error offset for an Expr node, if possible.
+*/
+SQLITE_PRIVATE void sqlite3ExprSetErrorOffset(Expr *pExpr, int iOfst){
+  if( pExpr==0 ) return;
+  if( NEVER(ExprUseWJoin(pExpr)) ) return;
+  pExpr->w.iOfst = iOfst;
+}
+
+/*
+** This routine is the core allocator for Expr nodes.
+**
+** Construct a new expression node and return a pointer to it.  Memory
+** for this node and for the pToken argument is a single allocation
+** obtained from sqlite3DbMalloc().  The calling function
+** is responsible for making sure the node eventually gets freed.
+**
+** If dequote is true, then the token (if it exists) is dequoted.
+** If dequote is false, no dequoting is performed.  The deQuote
+** parameter is ignored if pToken is NULL or if the token does not
+** appear to be quoted.  If the quotes were of the form "..." (double-quotes)
+** then the EP_DblQuoted flag is set on the expression node.
+**
+** Special case (tag-20240227-a):  If op==TK_INTEGER and pToken points to
+** a string that can be translated into a 32-bit integer, then the token is
+** not stored in u.zToken.  Instead, the integer values is written
+** into u.iValue and the EP_IntValue flag is set. No extra storage
+** is allocated to hold the integer text and the dequote flag is ignored.
+** See also tag-20240227-b.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprAlloc(
+  sqlite3 *db,            /* Handle for sqlite3DbMallocRawNN() */
+  int op,                 /* Expression opcode */
+  const Token *pToken,    /* Token argument.  Might be NULL */
+  int dequote             /* True to dequote */
+){
+  Expr *pNew;
+  int nExtra = 0;
+  int iValue = 0;
+
+  assert( db!=0 );
+  if( pToken ){
+    if( op!=TK_INTEGER || pToken->z==0
+          || sqlite3GetInt32(pToken->z, &iValue)==0 ){
+      nExtra = pToken->n+1;  /* tag-20240227-a */
+      assert( iValue>=0 );
+    }
+  }
+  pNew = sqlite3DbMallocRawNN(db, sizeof(Expr)+nExtra);
+  if( pNew ){
+    memset(pNew, 0, sizeof(Expr));
+    pNew->op = (u8)op;
+    pNew->iAgg = -1;
+    if( pToken ){
+      if( nExtra==0 ){
+        pNew->flags |= EP_IntValue|EP_Leaf|(iValue?EP_IsTrue:EP_IsFalse);
+        pNew->u.iValue = iValue;
+      }else{
+        pNew->u.zToken = (char*)&pNew[1];
+        assert( pToken->z!=0 || pToken->n==0 );
+        if( pToken->n ) memcpy(pNew->u.zToken, pToken->z, pToken->n);
+        pNew->u.zToken[pToken->n] = 0;
+        if( dequote && sqlite3Isquote(pNew->u.zToken[0]) ){
+          sqlite3DequoteExpr(pNew);
+        }
+      }
+    }
+#if SQLITE_MAX_EXPR_DEPTH>0
+    pNew->nHeight = 1;
+#endif
+  }
+  return pNew;
+}
+
+/*
+** Allocate a new expression node from a zero-terminated token that has
+** already been dequoted.
+*/
+SQLITE_PRIVATE Expr *sqlite3Expr(
+  sqlite3 *db,            /* Handle for sqlite3DbMallocZero() (may be null) */
+  int op,                 /* Expression opcode */
+  const char *zToken      /* Token argument.  Might be NULL */
+){
+  Token x;
+  x.z = zToken;
+  x.n = sqlite3Strlen30(zToken);
+  return sqlite3ExprAlloc(db, op, &x, 0);
+}
+
+/*
+** Attach subtrees pLeft and pRight to the Expr node pRoot.
+**
+** If pRoot==NULL that means that a memory allocation error has occurred.
+** In that case, delete the subtrees pLeft and pRight.
+*/
+SQLITE_PRIVATE void sqlite3ExprAttachSubtrees(
+  sqlite3 *db,
+  Expr *pRoot,
+  Expr *pLeft,
+  Expr *pRight
+){
+  if( pRoot==0 ){
+    assert( db->mallocFailed );
+    sqlite3ExprDelete(db, pLeft);
+    sqlite3ExprDelete(db, pRight);
+  }else{
+    assert( ExprUseXList(pRoot) );
+    assert( pRoot->x.pSelect==0 );
+    if( pRight ){
+      pRoot->pRight = pRight;
+      pRoot->flags |= EP_Propagate & pRight->flags;
+#if SQLITE_MAX_EXPR_DEPTH>0
+      pRoot->nHeight = pRight->nHeight+1;
+    }else{
+      pRoot->nHeight = 1;
+#endif
+    }
+    if( pLeft ){
+      pRoot->pLeft = pLeft;
+      pRoot->flags |= EP_Propagate & pLeft->flags;
+#if SQLITE_MAX_EXPR_DEPTH>0
+      if( pLeft->nHeight>=pRoot->nHeight ){
+        pRoot->nHeight = pLeft->nHeight+1;
+      }
+#endif
+    }
+  }
+}
+
+/*
+** Allocate an Expr node which joins as many as two subtrees.
+**
+** One or both of the subtrees can be NULL.  Return a pointer to the new
+** Expr node.  Or, if an OOM error occurs, set pParse->db->mallocFailed,
+** free the subtrees and return NULL.
+*/
+SQLITE_PRIVATE Expr *sqlite3PExpr(
+  Parse *pParse,          /* Parsing context */
+  int op,                 /* Expression opcode */
+  Expr *pLeft,            /* Left operand */
+  Expr *pRight            /* Right operand */
+){
+  Expr *p;
+  p = sqlite3DbMallocRawNN(pParse->db, sizeof(Expr));
+  if( p ){
+    memset(p, 0, sizeof(Expr));
+    p->op = op & 0xff;
+    p->iAgg = -1;
+    sqlite3ExprAttachSubtrees(pParse->db, p, pLeft, pRight);
+    sqlite3ExprCheckHeight(pParse, p->nHeight);
+  }else{
+    sqlite3ExprDelete(pParse->db, pLeft);
+    sqlite3ExprDelete(pParse->db, pRight);
+  }
+  return p;
+}
+
+/*
+** Add pSelect to the Expr.x.pSelect field.  Or, if pExpr is NULL (due
+** do a memory allocation failure) then delete the pSelect object.
+*/
+SQLITE_PRIVATE void sqlite3PExprAddSelect(Parse *pParse, Expr *pExpr, Select *pSelect){
+  if( pExpr ){
+    pExpr->x.pSelect = pSelect;
+    ExprSetProperty(pExpr, EP_xIsSelect|EP_Subquery);
+    sqlite3ExprSetHeightAndFlags(pParse, pExpr);
+  }else{
+    assert( pParse->db->mallocFailed );
+    sqlite3SelectDelete(pParse->db, pSelect);
+  }
+}
+
+/*
+** Expression list pEList is a list of vector values. This function
+** converts the contents of pEList to a VALUES(...) Select statement
+** returning 1 row for each element of the list. For example, the
+** expression list:
+**
+**   ( (1,2), (3,4) (5,6) )
+**
+** is translated to the equivalent of:
+**
+**   VALUES(1,2), (3,4), (5,6)
+**
+** Each of the vector values in pEList must contain exactly nElem terms.
+** If a list element that is not a vector or does not contain nElem terms,
+** an error message is left in pParse.
+**
+** This is used as part of processing IN(...) expressions with a list
+** of vectors on the RHS. e.g. "... IN ((1,2), (3,4), (5,6))".
+*/
+SQLITE_PRIVATE Select *sqlite3ExprListToValues(Parse *pParse, int nElem, ExprList *pEList){
+  int ii;
+  Select *pRet = 0;
+  assert( nElem>1 );
+  for(ii=0; ii<pEList->nExpr; ii++){
+    Select *pSel;
+    Expr *pExpr = pEList->a[ii].pExpr;
+    int nExprElem;
+    if( pExpr->op==TK_VECTOR ){
+      assert( ExprUseXList(pExpr) );
+      nExprElem = pExpr->x.pList->nExpr;
+    }else{
+      nExprElem = 1;
+    }
+    if( nExprElem!=nElem ){
+      sqlite3ErrorMsg(pParse, "IN(...) element has %d term%s - expected %d",
+          nExprElem, nExprElem>1?"s":"", nElem
+      );
+      break;
+    }
+    assert( ExprUseXList(pExpr) );
+    pSel = sqlite3SelectNew(pParse, pExpr->x.pList, 0, 0, 0, 0, 0, SF_Values,0);
+    pExpr->x.pList = 0;
+    if( pSel ){
+      if( pRet ){
+        pSel->op = TK_ALL;
+        pSel->pPrior = pRet;
+      }
+      pRet = pSel;
+    }
+  }
+
+  if( pRet && pRet->pPrior ){
+    pRet->selFlags |= SF_MultiValue;
+  }
+  sqlite3ExprListDelete(pParse->db, pEList);
+  return pRet;
+}
+
+/*
+** Join two expressions using an AND operator.  If either expression is
+** NULL, then just return the other expression.
+**
+** If one side or the other of the AND is known to be false, and neither side
+** is part of an ON clause, then instead of returning an AND expression,
+** just return a constant expression with a value of false.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprAnd(Parse *pParse, Expr *pLeft, Expr *pRight){
+  sqlite3 *db = pParse->db;
+  if( pLeft==0  ){
+    return pRight;
+  }else if( pRight==0 ){
+    return pLeft;
+  }else{
+    u32 f = pLeft->flags | pRight->flags;
+    if( (f&(EP_OuterON|EP_InnerON|EP_IsFalse))==EP_IsFalse
+     && !IN_RENAME_OBJECT
+    ){
+      sqlite3ExprDeferredDelete(pParse, pLeft);
+      sqlite3ExprDeferredDelete(pParse, pRight);
+      return sqlite3Expr(db, TK_INTEGER, "0");
+    }else{
+      return sqlite3PExpr(pParse, TK_AND, pLeft, pRight);
+    }
+  }
+}
+
+/*
+** Construct a new expression node for a function with multiple
+** arguments.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprFunction(
+  Parse *pParse,        /* Parsing context */
+  ExprList *pList,      /* Argument list */
+  const Token *pToken,  /* Name of the function */
+  int eDistinct         /* SF_Distinct or SF_ALL or 0 */
+){
+  Expr *pNew;
+  sqlite3 *db = pParse->db;
+  assert( pToken );
+  pNew = sqlite3ExprAlloc(db, TK_FUNCTION, pToken, 1);
+  if( pNew==0 ){
+    sqlite3ExprListDelete(db, pList); /* Avoid memory leak when malloc fails */
+    return 0;
+  }
+  assert( !ExprHasProperty(pNew, EP_InnerON|EP_OuterON) );
+  pNew->w.iOfst = (int)(pToken->z - pParse->zTail);
+  if( pList
+   && pList->nExpr > pParse->db->aLimit[SQLITE_LIMIT_FUNCTION_ARG]
+   && !pParse->nested
+  ){
+    sqlite3ErrorMsg(pParse, "too many arguments on function %T", pToken);
+  }
+  pNew->x.pList = pList;
+  ExprSetProperty(pNew, EP_HasFunc);
+  assert( ExprUseXList(pNew) );
+  sqlite3ExprSetHeightAndFlags(pParse, pNew);
+  if( eDistinct==SF_Distinct ) ExprSetProperty(pNew, EP_Distinct);
+  return pNew;
+}
+
+/*
+** Report an error when attempting to use an ORDER BY clause within
+** the arguments of a non-aggregate function.
+*/
+SQLITE_PRIVATE void sqlite3ExprOrderByAggregateError(Parse *pParse, Expr *p){
+  sqlite3ErrorMsg(pParse,
+     "ORDER BY may not be used with non-aggregate %#T()", p
+  );
+}
+
+/*
+** Attach an ORDER BY clause to a function call.
+**
+**     functionname( arguments ORDER BY sortlist )
+**     \_____________________/          \______/
+**             pExpr                    pOrderBy
+**
+** The ORDER BY clause is inserted into a new Expr node of type TK_ORDER
+** and added to the Expr.pLeft field of the parent TK_FUNCTION node.
+*/
+SQLITE_PRIVATE void sqlite3ExprAddFunctionOrderBy(
+  Parse *pParse,        /* Parsing context */
+  Expr *pExpr,          /* The function call to which ORDER BY is to be added */
+  ExprList *pOrderBy    /* The ORDER BY clause to add */
+){
+  Expr *pOB;
+  sqlite3 *db = pParse->db;
+  if( NEVER(pOrderBy==0) ){
+    assert( db->mallocFailed );
+    return;
+  }
+  if( pExpr==0 ){
+    assert( db->mallocFailed );
+    sqlite3ExprListDelete(db, pOrderBy);
+    return;
+  }
+  assert( pExpr->op==TK_FUNCTION );
+  assert( pExpr->pLeft==0 );
+  assert( ExprUseXList(pExpr) );
+  if( pExpr->x.pList==0 || NEVER(pExpr->x.pList->nExpr==0) ){
+    /* Ignore ORDER BY on zero-argument aggregates */
+    sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric, pOrderBy);
+    return;
+  }
+  if( IsWindowFunc(pExpr) ){
+    sqlite3ExprOrderByAggregateError(pParse, pExpr);
+    sqlite3ExprListDelete(db, pOrderBy);
+    return;
+  }
+
+  pOB = sqlite3ExprAlloc(db, TK_ORDER, 0, 0);
+  if( pOB==0 ){
+    sqlite3ExprListDelete(db, pOrderBy);
+    return;
+  }
+  pOB->x.pList = pOrderBy;
+  assert( ExprUseXList(pOB) );
+  pExpr->pLeft = pOB;
+  ExprSetProperty(pOB, EP_FullSize);
+}
+
+/*
+** Check to see if a function is usable according to current access
+** rules:
+**
+**    SQLITE_FUNC_DIRECT    -     Only usable from top-level SQL
+**
+**    SQLITE_FUNC_UNSAFE    -     Usable if TRUSTED_SCHEMA or from
+**                                top-level SQL
+**
+** If the function is not usable, create an error.
+*/
+SQLITE_PRIVATE void sqlite3ExprFunctionUsable(
+  Parse *pParse,         /* Parsing and code generating context */
+  const Expr *pExpr,     /* The function invocation */
+  const FuncDef *pDef    /* The function being invoked */
+){
+  assert( !IN_RENAME_OBJECT );
+  assert( (pDef->funcFlags & (SQLITE_FUNC_DIRECT|SQLITE_FUNC_UNSAFE))!=0 );
+  if( ExprHasProperty(pExpr, EP_FromDDL) ){
+    if( (pDef->funcFlags & SQLITE_FUNC_DIRECT)!=0
+     || (pParse->db->flags & SQLITE_TrustedSchema)==0
+    ){
+      /* Functions prohibited in triggers and views if:
+      **     (1) tagged with SQLITE_DIRECTONLY
+      **     (2) not tagged with SQLITE_INNOCUOUS (which means it
+      **         is tagged with SQLITE_FUNC_UNSAFE) and
+      **         SQLITE_DBCONFIG_TRUSTED_SCHEMA is off (meaning
+      **         that the schema is possibly tainted).
+      */
+      sqlite3ErrorMsg(pParse, "unsafe use of %#T()", pExpr);
+    }
+  }
+}
+
+/*
+** Assign a variable number to an expression that encodes a wildcard
+** in the original SQL statement.
+**
+** Wildcards consisting of a single "?" are assigned the next sequential
+** variable number.
+**
+** Wildcards of the form "?nnn" are assigned the number "nnn".  We make
+** sure "nnn" is not too big to avoid a denial of service attack when
+** the SQL statement comes from an external source.
+**
+** Wildcards of the form ":aaa", "@aaa", or "$aaa" are assigned the same number
+** as the previous instance of the same wildcard.  Or if this is the first
+** instance of the wildcard, the next sequential variable number is
+** assigned.
+*/
+SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr, u32 n){
+  sqlite3 *db = pParse->db;
+  const char *z;
+  ynVar x;
+
+  if( pExpr==0 ) return;
+  assert( !ExprHasProperty(pExpr, EP_IntValue|EP_Reduced|EP_TokenOnly) );
+  z = pExpr->u.zToken;
+  assert( z!=0 );
+  assert( z[0]!=0 );
+  assert( n==(u32)sqlite3Strlen30(z) );
+  if( z[1]==0 ){
+    /* Wildcard of the form "?".  Assign the next variable number */
+    assert( z[0]=='?' );
+    x = (ynVar)(++pParse->nVar);
+  }else{
+    int doAdd = 0;
+    if( z[0]=='?' ){
+      /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
+      ** use it as the variable number */
+      i64 i;
+      int bOk;
+      if( n==2 ){ /*OPTIMIZATION-IF-TRUE*/
+        i = z[1]-'0';  /* The common case of ?N for a single digit N */
+        bOk = 1;
+      }else{
+        bOk = 0==sqlite3Atoi64(&z[1], &i, n-1, SQLITE_UTF8);
+      }
+      testcase( i==0 );
+      testcase( i==1 );
+      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
+      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
+      if( bOk==0 || i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+        sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
+            db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
+        sqlite3RecordErrorOffsetOfExpr(pParse->db, pExpr);
+        return;
+      }
+      x = (ynVar)i;
+      if( x>pParse->nVar ){
+        pParse->nVar = (int)x;
+        doAdd = 1;
+      }else if( sqlite3VListNumToName(pParse->pVList, x)==0 ){
+        doAdd = 1;
+      }
+    }else{
+      /* Wildcards like ":aaa", "$aaa" or "@aaa".  Reuse the same variable
+      ** number as the prior appearance of the same name, or if the name
+      ** has never appeared before, reuse the same variable number
+      */
+      x = (ynVar)sqlite3VListNameToNum(pParse->pVList, z, n);
+      if( x==0 ){
+        x = (ynVar)(++pParse->nVar);
+        doAdd = 1;
+      }
+    }
+    if( doAdd ){
+      pParse->pVList = sqlite3VListAdd(db, pParse->pVList, z, n, x);
+    }
+  }
+  pExpr->iColumn = x;
+  if( x>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+    sqlite3ErrorMsg(pParse, "too many SQL variables");
+    sqlite3RecordErrorOffsetOfExpr(pParse->db, pExpr);
+  }
+}
+
+/*
+** Recursively delete an expression tree.
+*/
+static SQLITE_NOINLINE void sqlite3ExprDeleteNN(sqlite3 *db, Expr *p){
+  assert( p!=0 );
+  assert( db!=0 );
+exprDeleteRestart:
+  assert( !ExprUseUValue(p) || p->u.iValue>=0 );
+  assert( !ExprUseYWin(p) || !ExprUseYSub(p) );
+  assert( !ExprUseYWin(p) || p->y.pWin!=0 || db->mallocFailed );
+  assert( p->op!=TK_FUNCTION || !ExprUseYSub(p) );
+#ifdef SQLITE_DEBUG
+  if( ExprHasProperty(p, EP_Leaf) && !ExprHasProperty(p, EP_TokenOnly) ){
+    assert( p->pLeft==0 );
+    assert( p->pRight==0 );
+    assert( !ExprUseXSelect(p) || p->x.pSelect==0 );
+    assert( !ExprUseXList(p) || p->x.pList==0 );
+  }
+#endif
+  if( !ExprHasProperty(p, (EP_TokenOnly|EP_Leaf)) ){
+    /* The Expr.x union is never used at the same time as Expr.pRight */
+    assert( (ExprUseXList(p) && p->x.pList==0) || p->pRight==0 );
+    if( p->pRight ){
+      assert( !ExprHasProperty(p, EP_WinFunc) );
+      sqlite3ExprDeleteNN(db, p->pRight);
+    }else if( ExprUseXSelect(p) ){
+      assert( !ExprHasProperty(p, EP_WinFunc) );
+      sqlite3SelectDelete(db, p->x.pSelect);
+    }else{
+      sqlite3ExprListDelete(db, p->x.pList);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( ExprHasProperty(p, EP_WinFunc) ){
+        sqlite3WindowDelete(db, p->y.pWin);
+      }
+#endif
+    }
+    if( p->pLeft && p->op!=TK_SELECT_COLUMN ){
+      Expr *pLeft = p->pLeft;
+      if( !ExprHasProperty(p, EP_Static)
+       && !ExprHasProperty(pLeft, EP_Static)
+      ){
+        /* Avoid unnecessary recursion on unary operators */
+        sqlite3DbNNFreeNN(db, p);
+        p = pLeft;
+        goto exprDeleteRestart;
+      }else{
+        sqlite3ExprDeleteNN(db, pLeft);
+      }
+    }
+  }
+  if( !ExprHasProperty(p, EP_Static) ){
+    sqlite3DbNNFreeNN(db, p);
+  }
+}
+SQLITE_PRIVATE void sqlite3ExprDelete(sqlite3 *db, Expr *p){
+  if( p ) sqlite3ExprDeleteNN(db, p);
+}
+SQLITE_PRIVATE void sqlite3ExprDeleteGeneric(sqlite3 *db, void *p){
+  if( ALWAYS(p) ) sqlite3ExprDeleteNN(db, (Expr*)p);
+}
+
+/*
+** Clear both elements of an OnOrUsing object
+*/
+SQLITE_PRIVATE void sqlite3ClearOnOrUsing(sqlite3 *db, OnOrUsing *p){
+  if( p==0 ){
+    /* Nothing to clear */
+  }else if( p->pOn ){
+    sqlite3ExprDeleteNN(db, p->pOn);
+  }else if( p->pUsing ){
+    sqlite3IdListDelete(db, p->pUsing);
+  }
+}
+
+/*
+** Arrange to cause pExpr to be deleted when the pParse is deleted.
+** This is similar to sqlite3ExprDelete() except that the delete is
+** deferred until the pParse is deleted.
+**
+** The pExpr might be deleted immediately on an OOM error.
+**
+** Return 0 if the delete was successfully deferred.  Return non-zero
+** if the delete happened immediately because of an OOM.
+*/
+SQLITE_PRIVATE int sqlite3ExprDeferredDelete(Parse *pParse, Expr *pExpr){
+  return 0==sqlite3ParserAddCleanup(pParse, sqlite3ExprDeleteGeneric, pExpr);
+}
+
+/* Invoke sqlite3RenameExprUnmap() and sqlite3ExprDelete() on the
+** expression.
+*/
+SQLITE_PRIVATE void sqlite3ExprUnmapAndDelete(Parse *pParse, Expr *p){
+  if( p ){
+    if( IN_RENAME_OBJECT ){
+      sqlite3RenameExprUnmap(pParse, p);
+    }
+    sqlite3ExprDeleteNN(pParse->db, p);
+  }
+}
+
+/*
+** Return the number of bytes allocated for the expression structure
+** passed as the first argument. This is always one of EXPR_FULLSIZE,
+** EXPR_REDUCEDSIZE or EXPR_TOKENONLYSIZE.
+*/
+static int exprStructSize(const Expr *p){
+  if( ExprHasProperty(p, EP_TokenOnly) ) return EXPR_TOKENONLYSIZE;
+  if( ExprHasProperty(p, EP_Reduced) ) return EXPR_REDUCEDSIZE;
+  return EXPR_FULLSIZE;
+}
+
+/*
+** The dupedExpr*Size() routines each return the number of bytes required
+** to store a copy of an expression or expression tree.  They differ in
+** how much of the tree is measured.
+**
+**     dupedExprStructSize()     Size of only the Expr structure
+**     dupedExprNodeSize()       Size of Expr + space for token
+**     dupedExprSize()           Expr + token + subtree components
+**
+***************************************************************************
+**
+** The dupedExprStructSize() function returns two values OR-ed together:
+** (1) the space required for a copy of the Expr structure only and
+** (2) the EP_xxx flags that indicate what the structure size should be.
+** The return values is always one of:
+**
+**      EXPR_FULLSIZE
+**      EXPR_REDUCEDSIZE   | EP_Reduced
+**      EXPR_TOKENONLYSIZE | EP_TokenOnly
+**
+** The size of the structure can be found by masking the return value
+** of this routine with 0xfff.  The flags can be found by masking the
+** return value with EP_Reduced|EP_TokenOnly.
+**
+** Note that with flags==EXPRDUP_REDUCE, this routines works on full-size
+** (unreduced) Expr objects as they or originally constructed by the parser.
+** During expression analysis, extra information is computed and moved into
+** later parts of the Expr object and that extra information might get chopped
+** off if the expression is reduced.  Note also that it does not work to
+** make an EXPRDUP_REDUCE copy of a reduced expression.  It is only legal
+** to reduce a pristine expression tree from the parser.  The implementation
+** of dupedExprStructSize() contain multiple assert() statements that attempt
+** to enforce this constraint.
+*/
+static int dupedExprStructSize(const Expr *p, int flags){
+  int nSize;
+  assert( flags==EXPRDUP_REDUCE || flags==0 ); /* Only one flag value allowed */
+  assert( EXPR_FULLSIZE<=0xfff );
+  assert( (0xfff & (EP_Reduced|EP_TokenOnly))==0 );
+  if( 0==flags || ExprHasProperty(p, EP_FullSize) ){
+    nSize = EXPR_FULLSIZE;
+  }else{
+    assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
+    assert( !ExprHasProperty(p, EP_OuterON) );
+    assert( !ExprHasVVAProperty(p, EP_NoReduce) );
+    if( p->pLeft || p->x.pList ){
+      nSize = EXPR_REDUCEDSIZE | EP_Reduced;
+    }else{
+      assert( p->pRight==0 );
+      nSize = EXPR_TOKENONLYSIZE | EP_TokenOnly;
+    }
+  }
+  return nSize;
+}
+
+/*
+** This function returns the space in bytes required to store the copy
+** of the Expr structure and a copy of the Expr.u.zToken string (if that
+** string is defined.)
+*/
+static int dupedExprNodeSize(const Expr *p, int flags){
+  int nByte = dupedExprStructSize(p, flags) & 0xfff;
+  if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+    nByte += sqlite3Strlen30NN(p->u.zToken)+1;
+  }
+  return ROUND8(nByte);
+}
+
+/*
+** Return the number of bytes required to create a duplicate of the
+** expression passed as the first argument.
+**
+** The value returned includes space to create a copy of the Expr struct
+** itself and the buffer referred to by Expr.u.zToken, if any.
+**
+** The return value includes space to duplicate all Expr nodes in the
+** tree formed by Expr.pLeft and Expr.pRight, but not any other
+** substructure such as Expr.x.pList, Expr.x.pSelect, and Expr.y.pWin.
+*/
+static int dupedExprSize(const Expr *p){
+  int nByte;
+  assert( p!=0 );
+  nByte = dupedExprNodeSize(p, EXPRDUP_REDUCE);
+  if( p->pLeft ) nByte += dupedExprSize(p->pLeft);
+  if( p->pRight ) nByte += dupedExprSize(p->pRight);
+  assert( nByte==ROUND8(nByte) );
+  return nByte;
+}
+
+/*
+** An EdupBuf is a memory allocation used to stored multiple Expr objects
+** together with their Expr.zToken content.  This is used to help implement
+** compression while doing sqlite3ExprDup().  The top-level Expr does the
+** allocation for itself and many of its decendents, then passes an instance
+** of the structure down into exprDup() so that they decendents can have
+** access to that memory.
+*/
+typedef struct EdupBuf EdupBuf;
+struct EdupBuf {
+  u8 *zAlloc;          /* Memory space available for storage */
+#ifdef SQLITE_DEBUG
+  u8 *zEnd;            /* First byte past the end of memory */
+#endif
+};
+
+/*
+** This function is similar to sqlite3ExprDup(), except that if pEdupBuf
+** is not NULL then it points to memory that can be used to store a copy
+** of the input Expr p together with its p->u.zToken (if any).  pEdupBuf
+** is updated with the new buffer tail prior to returning.
+*/
+static Expr *exprDup(
+  sqlite3 *db,          /* Database connection (for memory allocation) */
+  const Expr *p,        /* Expr tree to be duplicated */
+  int dupFlags,         /* EXPRDUP_REDUCE for compression.  0 if not */
+  EdupBuf *pEdupBuf     /* Preallocated storage space, or NULL */
+){
+  Expr *pNew;           /* Value to return */
+  EdupBuf sEdupBuf;     /* Memory space from which to build Expr object */
+  u32 staticFlag;       /* EP_Static if space not obtained from malloc */
+  int nToken = -1;       /* Space needed for p->u.zToken.  -1 means unknown */
+
+  assert( db!=0 );
+  assert( p );
+  assert( dupFlags==0 || dupFlags==EXPRDUP_REDUCE );
+  assert( pEdupBuf==0 || dupFlags==EXPRDUP_REDUCE );
+
+  /* Figure out where to write the new Expr structure. */
+  if( pEdupBuf ){
+    sEdupBuf.zAlloc = pEdupBuf->zAlloc;
+#ifdef SQLITE_DEBUG
+    sEdupBuf.zEnd = pEdupBuf->zEnd;
+#endif
+    staticFlag = EP_Static;
+    assert( sEdupBuf.zAlloc!=0 );
+    assert( dupFlags==EXPRDUP_REDUCE );
+  }else{
+    int nAlloc;
+    if( dupFlags ){
+      nAlloc = dupedExprSize(p);
+    }else if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+      nToken = sqlite3Strlen30NN(p->u.zToken)+1;
+      nAlloc = ROUND8(EXPR_FULLSIZE + nToken);
+    }else{
+      nToken = 0;
+      nAlloc = ROUND8(EXPR_FULLSIZE);
+    }
+    assert( nAlloc==ROUND8(nAlloc) );
+    sEdupBuf.zAlloc = sqlite3DbMallocRawNN(db, nAlloc);
+#ifdef SQLITE_DEBUG
+    sEdupBuf.zEnd = sEdupBuf.zAlloc ? sEdupBuf.zAlloc+nAlloc : 0;
+#endif
+
+    staticFlag = 0;
+  }
+  pNew = (Expr *)sEdupBuf.zAlloc;
+  assert( EIGHT_BYTE_ALIGNMENT(pNew) );
+
+  if( pNew ){
+    /* Set nNewSize to the size allocated for the structure pointed to
+    ** by pNew. This is either EXPR_FULLSIZE, EXPR_REDUCEDSIZE or
+    ** EXPR_TOKENONLYSIZE. nToken is set to the number of bytes consumed
+    ** by the copy of the p->u.zToken string (if any).
+    */
+    const unsigned nStructSize = dupedExprStructSize(p, dupFlags);
+    int nNewSize = nStructSize & 0xfff;
+    if( nToken<0 ){
+      if( !ExprHasProperty(p, EP_IntValue) && p->u.zToken ){
+        nToken = sqlite3Strlen30(p->u.zToken) + 1;
+      }else{
+        nToken = 0;
+      }
+    }
+    if( dupFlags ){
+      assert( (int)(sEdupBuf.zEnd - sEdupBuf.zAlloc) >= nNewSize+nToken );
+      assert( ExprHasProperty(p, EP_Reduced)==0 );
+      memcpy(sEdupBuf.zAlloc, p, nNewSize);
+    }else{
+      u32 nSize = (u32)exprStructSize(p);
+      assert( (int)(sEdupBuf.zEnd - sEdupBuf.zAlloc) >=
+                                                   (int)EXPR_FULLSIZE+nToken );
+      memcpy(sEdupBuf.zAlloc, p, nSize);
+      if( nSize<EXPR_FULLSIZE ){
+        memset(&sEdupBuf.zAlloc[nSize], 0, EXPR_FULLSIZE-nSize);
+      }
+      nNewSize = EXPR_FULLSIZE;
+    }
+
+    /* Set the EP_Reduced, EP_TokenOnly, and EP_Static flags appropriately. */
+    pNew->flags &= ~(EP_Reduced|EP_TokenOnly|EP_Static);
+    pNew->flags |= nStructSize & (EP_Reduced|EP_TokenOnly);
+    pNew->flags |= staticFlag;
+    ExprClearVVAProperties(pNew);
+    if( dupFlags ){
+      ExprSetVVAProperty(pNew, EP_Immutable);
+    }
+
+    /* Copy the p->u.zToken string, if any. */
+    assert( nToken>=0 );
+    if( nToken>0 ){
+      char *zToken = pNew->u.zToken = (char*)&sEdupBuf.zAlloc[nNewSize];
+      memcpy(zToken, p->u.zToken, nToken);
+      nNewSize += nToken;
+    }
+    sEdupBuf.zAlloc += ROUND8(nNewSize);
+
+    if( ((p->flags|pNew->flags)&(EP_TokenOnly|EP_Leaf))==0 ){
+
+      /* Fill in the pNew->x.pSelect or pNew->x.pList member. */
+      if( ExprUseXSelect(p) ){
+        pNew->x.pSelect = sqlite3SelectDup(db, p->x.pSelect, dupFlags);
+      }else{
+        pNew->x.pList = sqlite3ExprListDup(db, p->x.pList,
+                           p->op!=TK_ORDER ? dupFlags : 0);
+      }
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( ExprHasProperty(p, EP_WinFunc) ){
+        pNew->y.pWin = sqlite3WindowDup(db, pNew, p->y.pWin);
+        assert( ExprHasProperty(pNew, EP_WinFunc) );
+      }
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+      /* Fill in pNew->pLeft and pNew->pRight. */
+      if( dupFlags ){
+        if( p->op==TK_SELECT_COLUMN ){
+          pNew->pLeft = p->pLeft;
+          assert( p->pRight==0
+               || p->pRight==p->pLeft
+               || ExprHasProperty(p->pLeft, EP_Subquery) );
+        }else{
+          pNew->pLeft = p->pLeft ?
+                      exprDup(db, p->pLeft, EXPRDUP_REDUCE, &sEdupBuf) : 0;
+        }
+        pNew->pRight = p->pRight ?
+                       exprDup(db, p->pRight, EXPRDUP_REDUCE, &sEdupBuf) : 0;
+      }else{
+        if( p->op==TK_SELECT_COLUMN ){
+          pNew->pLeft = p->pLeft;
+          assert( p->pRight==0
+               || p->pRight==p->pLeft
+               || ExprHasProperty(p->pLeft, EP_Subquery) );
+        }else{
+          pNew->pLeft = sqlite3ExprDup(db, p->pLeft, 0);
+        }
+        pNew->pRight = sqlite3ExprDup(db, p->pRight, 0);
+      }
+    }
+  }
+  if( pEdupBuf ) memcpy(pEdupBuf, &sEdupBuf, sizeof(sEdupBuf));
+  assert( sEdupBuf.zAlloc <= sEdupBuf.zEnd );
+  return pNew;
+}
+
+/*
+** Create and return a deep copy of the object passed as the second
+** argument. If an OOM condition is encountered, NULL is returned
+** and the db->mallocFailed flag set.
+*/
+#ifndef SQLITE_OMIT_CTE
+SQLITE_PRIVATE With *sqlite3WithDup(sqlite3 *db, With *p){
+  With *pRet = 0;
+  if( p ){
+    sqlite3_int64 nByte = sizeof(*p) + sizeof(p->a[0]) * (p->nCte-1);
+    pRet = sqlite3DbMallocZero(db, nByte);
+    if( pRet ){
+      int i;
+      pRet->nCte = p->nCte;
+      for(i=0; i<p->nCte; i++){
+        pRet->a[i].pSelect = sqlite3SelectDup(db, p->a[i].pSelect, 0);
+        pRet->a[i].pCols = sqlite3ExprListDup(db, p->a[i].pCols, 0);
+        pRet->a[i].zName = sqlite3DbStrDup(db, p->a[i].zName);
+        pRet->a[i].eM10d = p->a[i].eM10d;
+      }
+    }
+  }
+  return pRet;
+}
+#else
+# define sqlite3WithDup(x,y) 0
+#endif
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** The gatherSelectWindows() procedure and its helper routine
+** gatherSelectWindowsCallback() are used to scan all the expressions
+** an a newly duplicated SELECT statement and gather all of the Window
+** objects found there, assembling them onto the linked list at Select->pWin.
+*/
+static int gatherSelectWindowsCallback(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_FUNCTION && ExprHasProperty(pExpr, EP_WinFunc) ){
+    Select *pSelect = pWalker->u.pSelect;
+    Window *pWin = pExpr->y.pWin;
+    assert( pWin );
+    assert( IsWindowFunc(pExpr) );
+    assert( pWin->ppThis==0 );
+    sqlite3WindowLink(pSelect, pWin);
+  }
+  return WRC_Continue;
+}
+static int gatherSelectWindowsSelectCallback(Walker *pWalker, Select *p){
+  return p==pWalker->u.pSelect ? WRC_Continue : WRC_Prune;
+}
+static void gatherSelectWindows(Select *p){
+  Walker w;
+  w.xExprCallback = gatherSelectWindowsCallback;
+  w.xSelectCallback = gatherSelectWindowsSelectCallback;
+  w.xSelectCallback2 = 0;
+  w.pParse = 0;
+  w.u.pSelect = p;
+  sqlite3WalkSelect(&w, p);
+}
+#endif
+
+
+/*
+** The following group of routines make deep copies of expressions,
+** expression lists, ID lists, and select statements.  The copies can
+** be deleted (by being passed to their respective ...Delete() routines)
+** without effecting the originals.
+**
+** The expression list, ID, and source lists return by sqlite3ExprListDup(),
+** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded
+** by subsequent calls to sqlite*ListAppend() routines.
+**
+** Any tables that the SrcList might point to are not duplicated.
+**
+** The flags parameter contains a combination of the EXPRDUP_XXX flags.
+** If the EXPRDUP_REDUCE flag is set, then the structure returned is a
+** truncated version of the usual Expr structure that will be stored as
+** part of the in-memory representation of the database schema.
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3 *db, const Expr *p, int flags){
+  assert( flags==0 || flags==EXPRDUP_REDUCE );
+  return p ? exprDup(db, p, flags, 0) : 0;
+}
+SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3 *db, const ExprList *p, int flags){
+  ExprList *pNew;
+  struct ExprList_item *pItem;
+  const struct ExprList_item *pOldItem;
+  int i;
+  Expr *pPriorSelectColOld = 0;
+  Expr *pPriorSelectColNew = 0;
+  assert( db!=0 );
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRawNN(db, sqlite3DbMallocSize(db, p));
+  if( pNew==0 ) return 0;
+  pNew->nExpr = p->nExpr;
+  pNew->nAlloc = p->nAlloc;
+  pItem = pNew->a;
+  pOldItem = p->a;
+  for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
+    Expr *pOldExpr = pOldItem->pExpr;
+    Expr *pNewExpr;
+    pItem->pExpr = sqlite3ExprDup(db, pOldExpr, flags);
+    if( pOldExpr
+     && pOldExpr->op==TK_SELECT_COLUMN
+     && (pNewExpr = pItem->pExpr)!=0
+    ){
+      if( pNewExpr->pRight ){
+        pPriorSelectColOld = pOldExpr->pRight;
+        pPriorSelectColNew = pNewExpr->pRight;
+        pNewExpr->pLeft = pNewExpr->pRight;
+      }else{
+        if( pOldExpr->pLeft!=pPriorSelectColOld ){
+          pPriorSelectColOld = pOldExpr->pLeft;
+          pPriorSelectColNew = sqlite3ExprDup(db, pPriorSelectColOld, flags);
+          pNewExpr->pRight = pPriorSelectColNew;
+        }
+        pNewExpr->pLeft = pPriorSelectColNew;
+      }
+    }
+    pItem->zEName = sqlite3DbStrDup(db, pOldItem->zEName);
+    pItem->fg = pOldItem->fg;
+    pItem->fg.done = 0;
+    pItem->u = pOldItem->u;
+  }
+  return pNew;
+}
+
+/*
+** If cursors, triggers, views and subqueries are all omitted from
+** the build, then none of the following routines, except for
+** sqlite3SelectDup(), can be called. sqlite3SelectDup() is sometimes
+** called with a NULL argument.
+*/
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
+ || !defined(SQLITE_OMIT_SUBQUERY)
+SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
+  SrcList *pNew;
+  int i;
+  int nByte;
+  assert( db!=0 );
+  if( p==0 ) return 0;
+  nByte = sizeof(*p) + (p->nSrc>0 ? sizeof(p->a[0]) * (p->nSrc-1) : 0);
+  pNew = sqlite3DbMallocRawNN(db, nByte );
+  if( pNew==0 ) return 0;
+  pNew->nSrc = pNew->nAlloc = p->nSrc;
+  for(i=0; i<p->nSrc; i++){
+    SrcItem *pNewItem = &pNew->a[i];
+    const SrcItem *pOldItem = &p->a[i];
+    Table *pTab;
+    pNewItem->fg = pOldItem->fg;
+    if( pOldItem->fg.isSubquery ){
+      Subquery *pNewSubq = sqlite3DbMallocRaw(db, sizeof(Subquery));
+      if( pNewSubq==0 ){
+        assert( db->mallocFailed );
+        pNewItem->fg.isSubquery = 0;
+      }else{
+        memcpy(pNewSubq, pOldItem->u4.pSubq, sizeof(*pNewSubq));
+        pNewSubq->pSelect = sqlite3SelectDup(db, pNewSubq->pSelect, flags);
+        if( pNewSubq->pSelect==0 ){
+          sqlite3DbFree(db, pNewSubq);
+          pNewSubq = 0;
+          pNewItem->fg.isSubquery = 0;
+        }
+      }
+      pNewItem->u4.pSubq = pNewSubq;
+    }else if( pOldItem->fg.fixedSchema ){
+      pNewItem->u4.pSchema = pOldItem->u4.pSchema;
+    }else{
+      pNewItem->u4.zDatabase = sqlite3DbStrDup(db, pOldItem->u4.zDatabase);
+    }
+    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
+    pNewItem->iCursor = pOldItem->iCursor;
+    if( pNewItem->fg.isIndexedBy ){
+      pNewItem->u1.zIndexedBy = sqlite3DbStrDup(db, pOldItem->u1.zIndexedBy);
+    }else if( pNewItem->fg.isTabFunc ){
+      pNewItem->u1.pFuncArg =
+          sqlite3ExprListDup(db, pOldItem->u1.pFuncArg, flags);
+    }else{
+      pNewItem->u1.nRow = pOldItem->u1.nRow;
+    }
+    pNewItem->u2 = pOldItem->u2;
+    if( pNewItem->fg.isCte ){
+      pNewItem->u2.pCteUse->nUse++;
+    }
+    pTab = pNewItem->pSTab = pOldItem->pSTab;
+    if( pTab ){
+      pTab->nTabRef++;
+    }
+    if( pOldItem->fg.isUsing ){
+      assert( pNewItem->fg.isUsing );
+      pNewItem->u3.pUsing = sqlite3IdListDup(db, pOldItem->u3.pUsing);
+    }else{
+      pNewItem->u3.pOn = sqlite3ExprDup(db, pOldItem->u3.pOn, flags);
+    }
+    pNewItem->colUsed = pOldItem->colUsed;
+  }
+  return pNew;
+}
+SQLITE_PRIVATE IdList *sqlite3IdListDup(sqlite3 *db, const IdList *p){
+  IdList *pNew;
+  int i;
+  assert( db!=0 );
+  if( p==0 ) return 0;
+  pNew = sqlite3DbMallocRawNN(db, sizeof(*pNew)+(p->nId-1)*sizeof(p->a[0]) );
+  if( pNew==0 ) return 0;
+  pNew->nId = p->nId;
+  for(i=0; i<p->nId; i++){
+    struct IdList_item *pNewItem = &pNew->a[i];
+    const struct IdList_item *pOldItem = &p->a[i];
+    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
+  }
+  return pNew;
+}
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, const Select *pDup, int flags){
+  Select *pRet = 0;
+  Select *pNext = 0;
+  Select **pp = &pRet;
+  const Select *p;
+
+  assert( db!=0 );
+  for(p=pDup; p; p=p->pPrior){
+    Select *pNew = sqlite3DbMallocRawNN(db, sizeof(*p) );
+    if( pNew==0 ) break;
+    pNew->pEList = sqlite3ExprListDup(db, p->pEList, flags);
+    pNew->pSrc = sqlite3SrcListDup(db, p->pSrc, flags);
+    pNew->pWhere = sqlite3ExprDup(db, p->pWhere, flags);
+    pNew->pGroupBy = sqlite3ExprListDup(db, p->pGroupBy, flags);
+    pNew->pHaving = sqlite3ExprDup(db, p->pHaving, flags);
+    pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy, flags);
+    pNew->op = p->op;
+    pNew->pNext = pNext;
+    pNew->pPrior = 0;
+    pNew->pLimit = sqlite3ExprDup(db, p->pLimit, flags);
+    pNew->iLimit = 0;
+    pNew->iOffset = 0;
+    pNew->selFlags = p->selFlags & ~SF_UsesEphemeral;
+    pNew->addrOpenEphm[0] = -1;
+    pNew->addrOpenEphm[1] = -1;
+    pNew->nSelectRow = p->nSelectRow;
+    pNew->pWith = sqlite3WithDup(db, p->pWith);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    pNew->pWin = 0;
+    pNew->pWinDefn = sqlite3WindowListDup(db, p->pWinDefn);
+    if( p->pWin && db->mallocFailed==0 ) gatherSelectWindows(pNew);
+#endif
+    pNew->selId = p->selId;
+    if( db->mallocFailed ){
+      /* Any prior OOM might have left the Select object incomplete.
+      ** Delete the whole thing rather than allow an incomplete Select
+      ** to be used by the code generator. */
+      pNew->pNext = 0;
+      sqlite3SelectDelete(db, pNew);
+      break;
+    }
+    *pp = pNew;
+    pp = &pNew->pPrior;
+    pNext = pNew;
+  }
+  return pRet;
+}
+#else
+SQLITE_PRIVATE Select *sqlite3SelectDup(sqlite3 *db, const Select *p, int flags){
+  assert( p==0 );
+  return 0;
+}
+#endif
+
+
+/*
+** Add a new element to the end of an expression list.  If pList is
+** initially NULL, then create a new expression list.
+**
+** The pList argument must be either NULL or a pointer to an ExprList
+** obtained from a prior call to sqlite3ExprListAppend().
+**
+** If a memory allocation error occurs, the entire list is freed and
+** NULL is returned.  If non-NULL is returned, then it is guaranteed
+** that the new entry was successfully appended.
+*/
+static const struct ExprList_item zeroItem = {0};
+SQLITE_PRIVATE SQLITE_NOINLINE ExprList *sqlite3ExprListAppendNew(
+  sqlite3 *db,            /* Database handle.  Used for memory allocation */
+  Expr *pExpr             /* Expression to be appended. Might be NULL */
+){
+  struct ExprList_item *pItem;
+  ExprList *pList;
+
+  pList = sqlite3DbMallocRawNN(db, sizeof(ExprList)+sizeof(pList->a[0])*4 );
+  if( pList==0 ){
+    sqlite3ExprDelete(db, pExpr);
+    return 0;
+  }
+  pList->nAlloc = 4;
+  pList->nExpr = 1;
+  pItem = &pList->a[0];
+  *pItem = zeroItem;
+  pItem->pExpr = pExpr;
+  return pList;
+}
+SQLITE_PRIVATE SQLITE_NOINLINE ExprList *sqlite3ExprListAppendGrow(
+  sqlite3 *db,            /* Database handle.  Used for memory allocation */
+  ExprList *pList,        /* List to which to append. Might be NULL */
+  Expr *pExpr             /* Expression to be appended. Might be NULL */
+){
+  struct ExprList_item *pItem;
+  ExprList *pNew;
+  pList->nAlloc *= 2;
+  pNew = sqlite3DbRealloc(db, pList,
+       sizeof(*pList)+(pList->nAlloc-1)*sizeof(pList->a[0]));
+  if( pNew==0 ){
+    sqlite3ExprListDelete(db, pList);
+    sqlite3ExprDelete(db, pExpr);
+    return 0;
+  }else{
+    pList = pNew;
+  }
+  pItem = &pList->a[pList->nExpr++];
+  *pItem = zeroItem;
+  pItem->pExpr = pExpr;
+  return pList;
+}
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppend(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to append. Might be NULL */
+  Expr *pExpr             /* Expression to be appended. Might be NULL */
+){
+  struct ExprList_item *pItem;
+  if( pList==0 ){
+    return sqlite3ExprListAppendNew(pParse->db,pExpr);
+  }
+  if( pList->nAlloc<pList->nExpr+1 ){
+    return sqlite3ExprListAppendGrow(pParse->db,pList,pExpr);
+  }
+  pItem = &pList->a[pList->nExpr++];
+  *pItem = zeroItem;
+  pItem->pExpr = pExpr;
+  return pList;
+}
+
+/*
+** pColumns and pExpr form a vector assignment which is part of the SET
+** clause of an UPDATE statement.  Like this:
+**
+**        (a,b,c) = (expr1,expr2,expr3)
+** Or:    (a,b,c) = (SELECT x,y,z FROM ....)
+**
+** For each term of the vector assignment, append new entries to the
+** expression list pList.  In the case of a subquery on the RHS, append
+** TK_SELECT_COLUMN expressions.
+*/
+SQLITE_PRIVATE ExprList *sqlite3ExprListAppendVector(
+  Parse *pParse,         /* Parsing context */
+  ExprList *pList,       /* List to which to append. Might be NULL */
+  IdList *pColumns,      /* List of names of LHS of the assignment */
+  Expr *pExpr            /* Vector expression to be appended. Might be NULL */
+){
+  sqlite3 *db = pParse->db;
+  int n;
+  int i;
+  int iFirst = pList ? pList->nExpr : 0;
+  /* pColumns can only be NULL due to an OOM but an OOM will cause an
+  ** exit prior to this routine being invoked */
+  if( NEVER(pColumns==0) ) goto vector_append_error;
+  if( pExpr==0 ) goto vector_append_error;
+
+  /* If the RHS is a vector, then we can immediately check to see that
+  ** the size of the RHS and LHS match.  But if the RHS is a SELECT,
+  ** wildcards ("*") in the result set of the SELECT must be expanded before
+  ** we can do the size check, so defer the size check until code generation.
+  */
+  if( pExpr->op!=TK_SELECT && pColumns->nId!=(n=sqlite3ExprVectorSize(pExpr)) ){
+    sqlite3ErrorMsg(pParse, "%d columns assigned %d values",
+                    pColumns->nId, n);
+    goto vector_append_error;
+  }
+
+  for(i=0; i<pColumns->nId; i++){
+    Expr *pSubExpr = sqlite3ExprForVectorField(pParse, pExpr, i, pColumns->nId);
+    assert( pSubExpr!=0 || db->mallocFailed );
+    if( pSubExpr==0 ) continue;
+    pList = sqlite3ExprListAppend(pParse, pList, pSubExpr);
+    if( pList ){
+      assert( pList->nExpr==iFirst+i+1 );
+      pList->a[pList->nExpr-1].zEName = pColumns->a[i].zName;
+      pColumns->a[i].zName = 0;
+    }
+  }
+
+  if( !db->mallocFailed && pExpr->op==TK_SELECT && ALWAYS(pList!=0) ){
+    Expr *pFirst = pList->a[iFirst].pExpr;
+    assert( pFirst!=0 );
+    assert( pFirst->op==TK_SELECT_COLUMN );
+
+    /* Store the SELECT statement in pRight so it will be deleted when
+    ** sqlite3ExprListDelete() is called */
+    pFirst->pRight = pExpr;
+    pExpr = 0;
+
+    /* Remember the size of the LHS in iTable so that we can check that
+    ** the RHS and LHS sizes match during code generation. */
+    pFirst->iTable = pColumns->nId;
+  }
+
+vector_append_error:
+  sqlite3ExprUnmapAndDelete(pParse, pExpr);
+  sqlite3IdListDelete(db, pColumns);
+  return pList;
+}
+
+/*
+** Set the sort order for the last element on the given ExprList.
+*/
+SQLITE_PRIVATE void sqlite3ExprListSetSortOrder(ExprList *p, int iSortOrder, int eNulls){
+  struct ExprList_item *pItem;
+  if( p==0 ) return;
+  assert( p->nExpr>0 );
+
+  assert( SQLITE_SO_UNDEFINED<0 && SQLITE_SO_ASC==0 && SQLITE_SO_DESC>0 );
+  assert( iSortOrder==SQLITE_SO_UNDEFINED
+       || iSortOrder==SQLITE_SO_ASC
+       || iSortOrder==SQLITE_SO_DESC
+  );
+  assert( eNulls==SQLITE_SO_UNDEFINED
+       || eNulls==SQLITE_SO_ASC
+       || eNulls==SQLITE_SO_DESC
+  );
+
+  pItem = &p->a[p->nExpr-1];
+  assert( pItem->fg.bNulls==0 );
+  if( iSortOrder==SQLITE_SO_UNDEFINED ){
+    iSortOrder = SQLITE_SO_ASC;
+  }
+  pItem->fg.sortFlags = (u8)iSortOrder;
+
+  if( eNulls!=SQLITE_SO_UNDEFINED ){
+    pItem->fg.bNulls = 1;
+    if( iSortOrder!=eNulls ){
+      pItem->fg.sortFlags |= KEYINFO_ORDER_BIGNULL;
+    }
+  }
+}
+
+/*
+** Set the ExprList.a[].zEName element of the most recently added item
+** on the expression list.
+**
+** pList might be NULL following an OOM error.  But pName should never be
+** NULL.  If a memory allocation fails, the pParse->db->mallocFailed flag
+** is set.
+*/
+SQLITE_PRIVATE void sqlite3ExprListSetName(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to add the span. */
+  const Token *pName,     /* Name to be added */
+  int dequote             /* True to cause the name to be dequoted */
+){
+  assert( pList!=0 || pParse->db->mallocFailed!=0 );
+  assert( pParse->eParseMode!=PARSE_MODE_UNMAP || dequote==0 );
+  if( pList ){
+    struct ExprList_item *pItem;
+    assert( pList->nExpr>0 );
+    pItem = &pList->a[pList->nExpr-1];
+    assert( pItem->zEName==0 );
+    assert( pItem->fg.eEName==ENAME_NAME );
+    pItem->zEName = sqlite3DbStrNDup(pParse->db, pName->z, pName->n);
+    if( dequote ){
+      /* If dequote==0, then pName->z does not point to part of a DDL
+      ** statement handled by the parser. And so no token need be added
+      ** to the token-map.  */
+      sqlite3Dequote(pItem->zEName);
+      if( IN_RENAME_OBJECT ){
+        sqlite3RenameTokenMap(pParse, (const void*)pItem->zEName, pName);
+      }
+    }
+  }
+}
+
+/*
+** Set the ExprList.a[].zSpan element of the most recently added item
+** on the expression list.
+**
+** pList might be NULL following an OOM error.  But pSpan should never be
+** NULL.  If a memory allocation fails, the pParse->db->mallocFailed flag
+** is set.
+*/
+SQLITE_PRIVATE void sqlite3ExprListSetSpan(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to add the span. */
+  const char *zStart,     /* Start of the span */
+  const char *zEnd        /* End of the span */
+){
+  sqlite3 *db = pParse->db;
+  assert( pList!=0 || db->mallocFailed!=0 );
+  if( pList ){
+    struct ExprList_item *pItem = &pList->a[pList->nExpr-1];
+    assert( pList->nExpr>0 );
+    if( pItem->zEName==0 ){
+      pItem->zEName = sqlite3DbSpanDup(db, zStart, zEnd);
+      pItem->fg.eEName = ENAME_SPAN;
+    }
+  }
+}
+
+/*
+** If the expression list pEList contains more than iLimit elements,
+** leave an error message in pParse.
+*/
+SQLITE_PRIVATE void sqlite3ExprListCheckLength(
+  Parse *pParse,
+  ExprList *pEList,
+  const char *zObject
+){
+  int mx = pParse->db->aLimit[SQLITE_LIMIT_COLUMN];
+  testcase( pEList && pEList->nExpr==mx );
+  testcase( pEList && pEList->nExpr==mx+1 );
+  if( pEList && pEList->nExpr>mx ){
+    sqlite3ErrorMsg(pParse, "too many columns in %s", zObject);
+  }
+}
+
+/*
+** Delete an entire expression list.
+*/
+static SQLITE_NOINLINE void exprListDeleteNN(sqlite3 *db, ExprList *pList){
+  int i = pList->nExpr;
+  struct ExprList_item *pItem =  pList->a;
+  assert( pList->nExpr>0 );
+  assert( db!=0 );
+  do{
+    sqlite3ExprDelete(db, pItem->pExpr);
+    if( pItem->zEName ) sqlite3DbNNFreeNN(db, pItem->zEName);
+    pItem++;
+  }while( --i>0 );
+  sqlite3DbNNFreeNN(db, pList);
+}
+SQLITE_PRIVATE void sqlite3ExprListDelete(sqlite3 *db, ExprList *pList){
+  if( pList ) exprListDeleteNN(db, pList);
+}
+SQLITE_PRIVATE void sqlite3ExprListDeleteGeneric(sqlite3 *db, void *pList){
+  if( ALWAYS(pList) ) exprListDeleteNN(db, (ExprList*)pList);
+}
+
+/*
+** Return the bitwise-OR of all Expr.flags fields in the given
+** ExprList.
+*/
+SQLITE_PRIVATE u32 sqlite3ExprListFlags(const ExprList *pList){
+  int i;
+  u32 m = 0;
+  assert( pList!=0 );
+  for(i=0; i<pList->nExpr; i++){
+     Expr *pExpr = pList->a[i].pExpr;
+     assert( pExpr!=0 );
+     m |= pExpr->flags;
+  }
+  return m;
+}
+
+/*
+** This is a SELECT-node callback for the expression walker that
+** always "fails".  By "fail" in this case, we mean set
+** pWalker->eCode to zero and abort.
+**
+** This callback is used by multiple expression walkers.
+*/
+SQLITE_PRIVATE int sqlite3SelectWalkFail(Walker *pWalker, Select *NotUsed){
+  UNUSED_PARAMETER(NotUsed);
+  pWalker->eCode = 0;
+  return WRC_Abort;
+}
+
+/*
+** Check the input string to see if it is "true" or "false" (in any case).
+**
+**       If the string is....           Return
+**         "true"                         EP_IsTrue
+**         "false"                        EP_IsFalse
+**         anything else                  0
+*/
+SQLITE_PRIVATE u32 sqlite3IsTrueOrFalse(const char *zIn){
+  if( sqlite3StrICmp(zIn, "true")==0  ) return EP_IsTrue;
+  if( sqlite3StrICmp(zIn, "false")==0 ) return EP_IsFalse;
+  return 0;
+}
+
+
+/*
+** If the input expression is an ID with the name "true" or "false"
+** then convert it into an TK_TRUEFALSE term.  Return non-zero if
+** the conversion happened, and zero if the expression is unaltered.
+*/
+SQLITE_PRIVATE int sqlite3ExprIdToTrueFalse(Expr *pExpr){
+  u32 v;
+  assert( pExpr->op==TK_ID || pExpr->op==TK_STRING );
+  if( !ExprHasProperty(pExpr, EP_Quoted|EP_IntValue)
+   && (v = sqlite3IsTrueOrFalse(pExpr->u.zToken))!=0
+  ){
+    pExpr->op = TK_TRUEFALSE;
+    ExprSetProperty(pExpr, v);
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** The argument must be a TK_TRUEFALSE Expr node.  Return 1 if it is TRUE
+** and 0 if it is FALSE.
+*/
+SQLITE_PRIVATE int sqlite3ExprTruthValue(const Expr *pExpr){
+  pExpr = sqlite3ExprSkipCollateAndLikely((Expr*)pExpr);
+  assert( pExpr->op==TK_TRUEFALSE );
+  assert( !ExprHasProperty(pExpr, EP_IntValue) );
+  assert( sqlite3StrICmp(pExpr->u.zToken,"true")==0
+       || sqlite3StrICmp(pExpr->u.zToken,"false")==0 );
+  return pExpr->u.zToken[4]==0;
+}
+
+/*
+** If pExpr is an AND or OR expression, try to simplify it by eliminating
+** terms that are always true or false.  Return the simplified expression.
+** Or return the original expression if no simplification is possible.
+**
+** Examples:
+**
+**     (x<10) AND true                =>   (x<10)
+**     (x<10) AND false               =>   false
+**     (x<10) AND (y=22 OR false)     =>   (x<10) AND (y=22)
+**     (x<10) AND (y=22 OR true)      =>   (x<10)
+**     (y=22) OR true                 =>   true
+*/
+SQLITE_PRIVATE Expr *sqlite3ExprSimplifiedAndOr(Expr *pExpr){
+  assert( pExpr!=0 );
+  if( pExpr->op==TK_AND || pExpr->op==TK_OR ){
+    Expr *pRight = sqlite3ExprSimplifiedAndOr(pExpr->pRight);
+    Expr *pLeft = sqlite3ExprSimplifiedAndOr(pExpr->pLeft);
+    if( ExprAlwaysTrue(pLeft) || ExprAlwaysFalse(pRight) ){
+      pExpr = pExpr->op==TK_AND ? pRight : pLeft;
+    }else if( ExprAlwaysTrue(pRight) || ExprAlwaysFalse(pLeft) ){
+      pExpr = pExpr->op==TK_AND ? pLeft : pRight;
+    }
+  }
+  return pExpr;
+}
+
+/*
+** pExpr is a TK_FUNCTION node.  Try to determine whether or not the
+** function is a constant function.  A function is constant if all of
+** the following are true:
+**
+**    (1)  It is a scalar function (not an aggregate or window function)
+**    (2)  It has either the SQLITE_FUNC_CONSTANT or SQLITE_FUNC_SLOCHNG
+**         property.
+**    (3)  All of its arguments are constants
+**
+** This routine sets pWalker->eCode to 0 if pExpr is not a constant.
+** It makes no changes to pWalker->eCode if pExpr is constant.  In
+** every case, it returns WRC_Abort.
+**
+** Called as a service subroutine from exprNodeIsConstant().
+*/
+static SQLITE_NOINLINE int exprNodeIsConstantFunction(
+  Walker *pWalker,
+  Expr *pExpr
+){
+  int n;             /* Number of arguments */
+  ExprList *pList;   /* List of arguments */
+  FuncDef *pDef;     /* The function */
+  sqlite3 *db;       /* The database */
+
+  assert( pExpr->op==TK_FUNCTION );
+  if( ExprHasProperty(pExpr, EP_TokenOnly)
+   || (pList = pExpr->x.pList)==0
+  ){;
+    n = 0;
+  }else{
+    n = pList->nExpr;
+    sqlite3WalkExprList(pWalker, pList);
+    if( pWalker->eCode==0 ) return WRC_Abort;
+  }
+  db = pWalker->pParse->db;
+  pDef = sqlite3FindFunction(db, pExpr->u.zToken, n, ENC(db), 0);
+  if( pDef==0
+   || pDef->xFinalize!=0
+   || (pDef->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG))==0
+   || ExprHasProperty(pExpr, EP_WinFunc)
+  ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+  return WRC_Prune;
+}
+
+
+/*
+** These routines are Walker callbacks used to check expressions to
+** see if they are "constant" for some definition of constant.  The
+** Walker.eCode value determines the type of "constant" we are looking
+** for.
+**
+** These callback routines are used to implement the following:
+**
+**     sqlite3ExprIsConstant()                  pWalker->eCode==1
+**     sqlite3ExprIsConstantNotJoin()           pWalker->eCode==2
+**     sqlite3ExprIsTableConstant()             pWalker->eCode==3
+**     sqlite3ExprIsConstantOrFunction()        pWalker->eCode==4 or 5
+**
+** In all cases, the callbacks set Walker.eCode=0 and abort if the expression
+** is found to not be a constant.
+**
+** The sqlite3ExprIsConstantOrFunction() is used for evaluating DEFAULT
+** expressions in a CREATE TABLE statement.  The Walker.eCode value is 5
+** when parsing an existing schema out of the sqlite_schema table and 4
+** when processing a new CREATE TABLE statement.  A bound parameter raises
+** an error for new statements, but is silently converted
+** to NULL for existing schemas.  This allows sqlite_schema tables that
+** contain a bound parameter because they were generated by older versions
+** of SQLite to be parsed by newer versions of SQLite without raising a
+** malformed schema error.
+*/
+static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){
+  assert( pWalker->eCode>0 );
+
+  /* If pWalker->eCode is 2 then any term of the expression that comes from
+  ** the ON or USING clauses of an outer join disqualifies the expression
+  ** from being considered constant. */
+  if( pWalker->eCode==2 && ExprHasProperty(pExpr, EP_OuterON) ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+
+  switch( pExpr->op ){
+    /* Consider functions to be constant if all their arguments are constant
+    ** and either pWalker->eCode==4 or 5 or the function has the
+    ** SQLITE_FUNC_CONST flag. */
+    case TK_FUNCTION:
+      if( (pWalker->eCode>=4 || ExprHasProperty(pExpr,EP_ConstFunc))
+       && !ExprHasProperty(pExpr, EP_WinFunc)
+      ){
+        if( pWalker->eCode==5 ) ExprSetProperty(pExpr, EP_FromDDL);
+        return WRC_Continue;
+      }else if( pWalker->pParse ){
+        return exprNodeIsConstantFunction(pWalker, pExpr);
+      }else{
+        pWalker->eCode = 0;
+        return WRC_Abort;
+      }
+    case TK_ID:
+      /* Convert "true" or "false" in a DEFAULT clause into the
+      ** appropriate TK_TRUEFALSE operator */
+      if( sqlite3ExprIdToTrueFalse(pExpr) ){
+        return WRC_Prune;
+      }
+      /* no break */ deliberate_fall_through
+    case TK_COLUMN:
+    case TK_AGG_FUNCTION:
+    case TK_AGG_COLUMN:
+      testcase( pExpr->op==TK_ID );
+      testcase( pExpr->op==TK_COLUMN );
+      testcase( pExpr->op==TK_AGG_FUNCTION );
+      testcase( pExpr->op==TK_AGG_COLUMN );
+      if( ExprHasProperty(pExpr, EP_FixedCol) && pWalker->eCode!=2 ){
+        return WRC_Continue;
+      }
+      if( pWalker->eCode==3 && pExpr->iTable==pWalker->u.iCur ){
+        return WRC_Continue;
+      }
+      /* no break */ deliberate_fall_through
+    case TK_IF_NULL_ROW:
+    case TK_REGISTER:
+    case TK_DOT:
+    case TK_RAISE:
+      testcase( pExpr->op==TK_REGISTER );
+      testcase( pExpr->op==TK_IF_NULL_ROW );
+      testcase( pExpr->op==TK_DOT );
+      testcase( pExpr->op==TK_RAISE );
+      pWalker->eCode = 0;
+      return WRC_Abort;
+    case TK_VARIABLE:
+      if( pWalker->eCode==5 ){
+        /* Silently convert bound parameters that appear inside of CREATE
+        ** statements into a NULL when parsing the CREATE statement text out
+        ** of the sqlite_schema table */
+        pExpr->op = TK_NULL;
+      }else if( pWalker->eCode==4 ){
+        /* A bound parameter in a CREATE statement that originates from
+        ** sqlite3_prepare() causes an error */
+        pWalker->eCode = 0;
+        return WRC_Abort;
+      }
+      /* no break */ deliberate_fall_through
+    default:
+      testcase( pExpr->op==TK_SELECT ); /* sqlite3SelectWalkFail() disallows */
+      testcase( pExpr->op==TK_EXISTS ); /* sqlite3SelectWalkFail() disallows */
+      return WRC_Continue;
+  }
+}
+static int exprIsConst(Parse *pParse, Expr *p, int initFlag){
+  Walker w;
+  w.eCode = initFlag;
+  w.pParse = pParse;
+  w.xExprCallback = exprNodeIsConstant;
+  w.xSelectCallback = sqlite3SelectWalkFail;
+#ifdef SQLITE_DEBUG
+  w.xSelectCallback2 = sqlite3SelectWalkAssert2;
+#endif
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+/*
+** Walk an expression tree.  Return non-zero if the expression is constant
+** and 0 if it involves variables or function calls.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+**
+** The pParse parameter may be NULL.  But if it is NULL, there is no way
+** to determine if function calls are constant or not, and hence all
+** function calls will be considered to be non-constant.  If pParse is
+** not NULL, then a function call might be constant, depending on the
+** function and on its parameters.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsConstant(Parse *pParse, Expr *p){
+  return exprIsConst(pParse, p, 1);
+}
+
+/*
+** Walk an expression tree.  Return non-zero if
+**
+**   (1) the expression is constant, and
+**   (2) the expression does originate in the ON or USING clause
+**       of a LEFT JOIN, and
+**   (3) the expression does not contain any EP_FixedCol TK_COLUMN
+**       operands created by the constant propagation optimization.
+**
+** When this routine returns true, it indicates that the expression
+** can be added to the pParse->pConstExpr list and evaluated once when
+** the prepared statement starts up.  See sqlite3ExprCodeRunJustOnce().
+*/
+static int sqlite3ExprIsConstantNotJoin(Parse *pParse, Expr *p){
+  return exprIsConst(pParse, p, 2);
+}
+
+/*
+** This routine examines sub-SELECT statements as an expression is being
+** walked as part of sqlite3ExprIsTableConstant().  Sub-SELECTs are considered
+** constant as long as they are uncorrelated - meaning that they do not
+** contain any terms from outer contexts.
+*/
+static int exprSelectWalkTableConstant(Walker *pWalker, Select *pSelect){
+  assert( pSelect!=0 );
+  assert( pWalker->eCode==3 || pWalker->eCode==0 );
+  if( (pSelect->selFlags & SF_Correlated)!=0 ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+  return WRC_Prune;
+}
+
+/*
+** Walk an expression tree.  Return non-zero if the expression is constant
+** for any single row of the table with cursor iCur.  In other words, the
+** expression must not refer to any non-deterministic function nor any
+** table other than iCur.
+**
+** Consider uncorrelated subqueries to be constants if the bAllowSubq
+** parameter is true.
+*/
+static int sqlite3ExprIsTableConstant(Expr *p, int iCur, int bAllowSubq){
+  Walker w;
+  w.eCode = 3;
+  w.pParse = 0;
+  w.xExprCallback = exprNodeIsConstant;
+  if( bAllowSubq ){
+    w.xSelectCallback = exprSelectWalkTableConstant;
+  }else{
+    w.xSelectCallback = sqlite3SelectWalkFail;
+#ifdef SQLITE_DEBUG
+    w.xSelectCallback2 = sqlite3SelectWalkAssert2;
+#endif
+  }
+  w.u.iCur = iCur;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+/*
+** Check pExpr to see if it is an constraint on the single data source
+** pSrc = &pSrcList->a[iSrc].  In other words, check to see if pExpr
+** constrains pSrc but does not depend on any other tables or data
+** sources anywhere else in the query.  Return true (non-zero) if pExpr
+** is a constraint on pSrc only.
+**
+** This is an optimization.  False negatives will perhaps cause slower
+** queries, but false positives will yield incorrect answers.  So when in
+** doubt, return 0.
+**
+** To be an single-source constraint, the following must be true:
+**
+**   (1)  pExpr cannot refer to any table other than pSrc->iCursor.
+**
+**   (2a) pExpr cannot use subqueries unless the bAllowSubq parameter is
+**        true and the subquery is non-correlated
+**
+**   (2b) pExpr cannot use non-deterministic functions.
+**
+**   (3)  pSrc cannot be part of the left operand for a RIGHT JOIN.
+**        (Is there some way to relax this constraint?)
+**
+**   (4)  If pSrc is the right operand of a LEFT JOIN, then...
+**         (4a)  pExpr must come from an ON clause..
+**         (4b)  and specifically the ON clause associated with the LEFT JOIN.
+**
+**   (5)  If pSrc is the right operand of a LEFT JOIN or the left
+**        operand of a RIGHT JOIN, then pExpr must be from the WHERE
+**        clause, not an ON clause.
+**
+**   (6) Either:
+**
+**       (6a) pExpr does not originate in an ON or USING clause, or
+**
+**       (6b) The ON or USING clause from which pExpr is derived is
+**            not to the left of a RIGHT JOIN (or FULL JOIN).
+**
+**       Without this restriction, accepting pExpr as a single-table
+**       constraint might move the the ON/USING filter expression
+**       from the left side of a RIGHT JOIN over to the right side,
+**       which leads to incorrect answers.  See also restriction (9)
+**       on push-down.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsSingleTableConstraint(
+  Expr *pExpr,                 /* The constraint */
+  const SrcList *pSrcList,     /* Complete FROM clause */
+  int iSrc,                    /* Which element of pSrcList to use */
+  int bAllowSubq               /* Allow non-correlated subqueries */
+){
+  const SrcItem *pSrc = &pSrcList->a[iSrc];
+  if( pSrc->fg.jointype & JT_LTORJ ){
+    return 0;  /* rule (3) */
+  }
+  if( pSrc->fg.jointype & JT_LEFT ){
+    if( !ExprHasProperty(pExpr, EP_OuterON) ) return 0;   /* rule (4a) */
+    if( pExpr->w.iJoin!=pSrc->iCursor ) return 0;         /* rule (4b) */
+  }else{
+    if( ExprHasProperty(pExpr, EP_OuterON) ) return 0;    /* rule (5) */
+  }
+  if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON)  /* (6a) */
+   && (pSrcList->a[0].fg.jointype & JT_LTORJ)!=0     /* Fast pre-test of (6b) */
+  ){
+    int jj;
+    for(jj=0; jj<iSrc; jj++){
+      if( pExpr->w.iJoin==pSrcList->a[jj].iCursor ){
+        if( (pSrcList->a[jj].fg.jointype & JT_LTORJ)!=0 ){
+          return 0;  /* restriction (6) */
+        }
+        break;
+      }
+    }
+  }
+  /* Rules (1), (2a), and (2b) handled by the following: */
+  return sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor, bAllowSubq);
+}
+
+
+/*
+** sqlite3WalkExpr() callback used by sqlite3ExprIsConstantOrGroupBy().
+*/
+static int exprNodeIsConstantOrGroupBy(Walker *pWalker, Expr *pExpr){
+  ExprList *pGroupBy = pWalker->u.pGroupBy;
+  int i;
+
+  /* Check if pExpr is identical to any GROUP BY term. If so, consider
+  ** it constant.  */
+  for(i=0; i<pGroupBy->nExpr; i++){
+    Expr *p = pGroupBy->a[i].pExpr;
+    if( sqlite3ExprCompare(0, pExpr, p, -1)<2 ){
+      CollSeq *pColl = sqlite3ExprNNCollSeq(pWalker->pParse, p);
+      if( sqlite3IsBinary(pColl) ){
+        return WRC_Prune;
+      }
+    }
+  }
+
+  /* Check if pExpr is a sub-select. If so, consider it variable. */
+  if( ExprUseXSelect(pExpr) ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+
+  return exprNodeIsConstant(pWalker, pExpr);
+}
+
+/*
+** Walk the expression tree passed as the first argument. Return non-zero
+** if the expression consists entirely of constants or copies of terms
+** in pGroupBy that sort with the BINARY collation sequence.
+**
+** This routine is used to determine if a term of the HAVING clause can
+** be promoted into the WHERE clause.  In order for such a promotion to work,
+** the value of the HAVING clause term must be the same for all members of
+** a "group".  The requirement that the GROUP BY term must be BINARY
+** assumes that no other collating sequence will have a finer-grained
+** grouping than binary.  In other words (A=B COLLATE binary) implies
+** A=B in every other collating sequence.  The requirement that the
+** GROUP BY be BINARY is stricter than necessary.  It would also work
+** to promote HAVING clauses that use the same alternative collating
+** sequence as the GROUP BY term, but that is much harder to check,
+** alternative collating sequences are uncommon, and this is only an
+** optimization, so we take the easy way out and simply require the
+** GROUP BY to use the BINARY collating sequence.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrGroupBy(Parse *pParse, Expr *p, ExprList *pGroupBy){
+  Walker w;
+  w.eCode = 1;
+  w.xExprCallback = exprNodeIsConstantOrGroupBy;
+  w.xSelectCallback = 0;
+  w.u.pGroupBy = pGroupBy;
+  w.pParse = pParse;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+/*
+** Walk an expression tree for the DEFAULT field of a column definition
+** in a CREATE TABLE statement.  Return non-zero if the expression is
+** acceptable for use as a DEFAULT.  That is to say, return non-zero if
+** the expression is constant or a function call with constant arguments.
+** Return and 0 if there are any variables.
+**
+** isInit is true when parsing from sqlite_schema.  isInit is false when
+** processing a new CREATE TABLE statement.  When isInit is true, parameters
+** (such as ? or $abc) in the expression are converted into NULL.  When
+** isInit is false, parameters raise an error.  Parameters should not be
+** allowed in a CREATE TABLE statement, but some legacy versions of SQLite
+** allowed it, so we need to support it when reading sqlite_schema for
+** backwards compatibility.
+**
+** If isInit is true, set EP_FromDDL on every TK_FUNCTION node.
+**
+** For the purposes of this function, a double-quoted string (ex: "abc")
+** is considered a variable but a single-quoted string (ex: 'abc') is
+** a constant.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsConstantOrFunction(Expr *p, u8 isInit){
+  assert( isInit==0 || isInit==1 );
+  return exprIsConst(0, p, 4+isInit);
+}
+
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/*
+** Walk an expression tree.  Return 1 if the expression contains a
+** subquery of some kind.  Return 0 if there are no subqueries.
+*/
+SQLITE_PRIVATE int sqlite3ExprContainsSubquery(Expr *p){
+  Walker w;
+  w.eCode = 1;
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.xSelectCallback = sqlite3SelectWalkFail;
+#ifdef SQLITE_DEBUG
+  w.xSelectCallback2 = sqlite3SelectWalkAssert2;
+#endif
+  sqlite3WalkExpr(&w, p);
+  return w.eCode==0;
+}
+#endif
+
+/*
+** If the expression p codes a constant integer that is small enough
+** to fit in a 32-bit integer, return 1 and put the value of the integer
+** in *pValue.  If the expression is not an integer or if it is too big
+** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
+**
+** If the pParse pointer is provided, then allow the expression p to be
+** a parameter (TK_VARIABLE) that is bound to an integer.
+** But if pParse is NULL, then p must be a pure integer literal.
+*/
+SQLITE_PRIVATE int sqlite3ExprIsInteger(const Expr *p, int *pValue, Parse *pParse){
+  int rc = 0;
+  if( NEVER(p==0) ) return 0;  /* Used to only happen following on OOM */
+
+  /* If an expression is an integer literal that fits in a signed 32-bit
+  ** integer, then the EP_IntValue flag will have already been set */
+  assert( p->op!=TK_INTEGER || (p->flags & EP_IntValue)!=0
+           || sqlite3GetInt32(p->u.zToken, &rc)==0 );
+
+  if( p->flags & EP_IntValue ){
+    *pValue = p->u.iValue;
+    return 1;
+  }
+  switch( p->op ){
+    case TK_UPLUS: {
+      rc = sqlite3ExprIsInteger(p->pLeft, pValue, 0);
+      break;
+    }
+    case TK_UMINUS: {
+      int v = 0;
+      if( sqlite3ExprIsInteger(p->pLeft, &v, 0) ){
+        assert( ((unsigned int)v)!=0x80000000 );
+        *pValue = -v;
+        rc = 1;
+      }
+      break;
+    }
+    case TK_VARIABLE: {
+      sqlite3_value *pVal;
+      if( pParse==0 ) break;
+      if( NEVER(pParse->pVdbe==0) ) break;
+      if( (pParse->db->flags & SQLITE_EnableQPSG)!=0 ) break;
+      sqlite3VdbeSetVarmask(pParse->pVdbe, p->iColumn);
+      pVal = sqlite3VdbeGetBoundValue(pParse->pReprepare, p->iColumn,
+                                      SQLITE_AFF_BLOB);
+      if( pVal ){
+        if( sqlite3_value_type(pVal)==SQLITE_INTEGER ){
+          sqlite3_int64 vv = sqlite3_value_int64(pVal);
+          if( vv == (vv & 0x7fffffff) ){ /* non-negative numbers only */
+            *pValue = (int)vv;
+            rc = 1;
+          }
+        }
+        sqlite3ValueFree(pVal);
+      }
+      break;
+    }
+    default: break;
+  }
+  return rc;
+}
+
+/*
+** Return FALSE if there is no chance that the expression can be NULL.
+**
+** If the expression might be NULL or if the expression is too complex
+** to tell return TRUE.
+**
+** This routine is used as an optimization, to skip OP_IsNull opcodes
+** when we know that a value cannot be NULL.  Hence, a false positive
+** (returning TRUE when in fact the expression can never be NULL) might
+** be a small performance hit but is otherwise harmless.  On the other
+** hand, a false negative (returning FALSE when the result could be NULL)
+** will likely result in an incorrect answer.  So when in doubt, return
+** TRUE.
+*/
+SQLITE_PRIVATE int sqlite3ExprCanBeNull(const Expr *p){
+  u8 op;
+  assert( p!=0 );
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){
+    p = p->pLeft;
+    assert( p!=0 );
+  }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER:
+    case TK_STRING:
+    case TK_FLOAT:
+    case TK_BLOB:
+      return 0;
+    case TK_COLUMN:
+      assert( ExprUseYTab(p) );
+      return ExprHasProperty(p, EP_CanBeNull)
+          || NEVER(p->y.pTab==0) /* Reference to column of index on expr */
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+          || (p->iColumn==XN_ROWID && IsView(p->y.pTab))
+#endif
+          || (p->iColumn>=0
+              && p->y.pTab->aCol!=0 /* Possible due to prior error */
+              && ALWAYS(p->iColumn<p->y.pTab->nCol)
+              && p->y.pTab->aCol[p->iColumn].notNull==0);
+    default:
+      return 1;
+  }
+}
+
+/*
+** Return TRUE if the given expression is a constant which would be
+** unchanged by OP_Affinity with the affinity given in the second
+** argument.
+**
+** This routine is used to determine if the OP_Affinity operation
+** can be omitted.  When in doubt return FALSE.  A false negative
+** is harmless.  A false positive, however, can result in the wrong
+** answer.
+*/
+SQLITE_PRIVATE int sqlite3ExprNeedsNoAffinityChange(const Expr *p, char aff){
+  u8 op;
+  int unaryMinus = 0;
+  if( aff==SQLITE_AFF_BLOB ) return 1;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){
+    if( p->op==TK_UMINUS ) unaryMinus = 1;
+    p = p->pLeft;
+  }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER: {
+      return aff>=SQLITE_AFF_NUMERIC;
+    }
+    case TK_FLOAT: {
+      return aff>=SQLITE_AFF_NUMERIC;
+    }
+    case TK_STRING: {
+      return !unaryMinus && aff==SQLITE_AFF_TEXT;
+    }
+    case TK_BLOB: {
+      return !unaryMinus;
+    }
+    case TK_COLUMN: {
+      assert( p->iTable>=0 );  /* p cannot be part of a CHECK constraint */
+      return aff>=SQLITE_AFF_NUMERIC && p->iColumn<0;
+    }
+    default: {
+      return 0;
+    }
+  }
+}
+
+/*
+** Return TRUE if the given string is a row-id column name.
+*/
+SQLITE_PRIVATE int sqlite3IsRowid(const char *z){
+  if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1;
+  if( sqlite3StrICmp(z, "ROWID")==0 ) return 1;
+  if( sqlite3StrICmp(z, "OID")==0 ) return 1;
+  return 0;
+}
+
+/*
+** Return a pointer to a buffer containing a usable rowid alias for table
+** pTab. An alias is usable if there is not an explicit user-defined column
+** of the same name.
+*/
+SQLITE_PRIVATE const char *sqlite3RowidAlias(Table *pTab){
+  const char *azOpt[] = {"_ROWID_", "ROWID", "OID"};
+  int ii;
+  assert( VisibleRowid(pTab) );
+  for(ii=0; ii<ArraySize(azOpt); ii++){
+    int iCol;
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      if( sqlite3_stricmp(azOpt[ii], pTab->aCol[iCol].zCnName)==0 ) break;
+    }
+    if( iCol==pTab->nCol ){
+      return azOpt[ii];
+    }
+  }
+  return 0;
+}
+
+/*
+** pX is the RHS of an IN operator.  If pX is a SELECT statement
+** that can be simplified to a direct table access, then return
+** a pointer to the SELECT statement.  If pX is not a SELECT statement,
+** or if the SELECT statement needs to be materialized into a transient
+** table, then return NULL.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+static Select *isCandidateForInOpt(const Expr *pX){
+  Select *p;
+  SrcList *pSrc;
+  ExprList *pEList;
+  Table *pTab;
+  int i;
+  if( !ExprUseXSelect(pX) ) return 0;                 /* Not a subquery */
+  if( ExprHasProperty(pX, EP_VarSelect)  ) return 0;  /* Correlated subq */
+  p = pX->x.pSelect;
+  if( p->pPrior ) return 0;              /* Not a compound SELECT */
+  if( p->selFlags & (SF_Distinct|SF_Aggregate) ){
+    testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
+    testcase( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
+    return 0; /* No DISTINCT keyword and no aggregate functions */
+  }
+  assert( p->pGroupBy==0 );              /* Has no GROUP BY clause */
+  if( p->pLimit ) return 0;              /* Has no LIMIT clause */
+  if( p->pWhere ) return 0;              /* Has no WHERE clause */
+  pSrc = p->pSrc;
+  assert( pSrc!=0 );
+  if( pSrc->nSrc!=1 ) return 0;          /* Single term in FROM clause */
+  if( pSrc->a[0].fg.isSubquery) return 0;/* FROM is not a subquery or view */
+  pTab = pSrc->a[0].pSTab;
+  assert( pTab!=0 );
+  assert( !IsView(pTab)  );              /* FROM clause is not a view */
+  if( IsVirtual(pTab) ) return 0;        /* FROM clause not a virtual table */
+  pEList = p->pEList;
+  assert( pEList!=0 );
+  /* All SELECT results must be columns. */
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *pRes = pEList->a[i].pExpr;
+    if( pRes->op!=TK_COLUMN ) return 0;
+    assert( pRes->iTable==pSrc->a[0].iCursor );  /* Not a correlated subquery */
+  }
+  return p;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code that checks the left-most column of index table iCur to see if
+** it contains any NULL entries.  Cause the register at regHasNull to be set
+** to a non-NULL value if iCur contains no NULLs.  Cause register regHasNull
+** to be set to NULL if iCur contains one or more NULL values.
+*/
+static void sqlite3SetHasNullFlag(Vdbe *v, int iCur, int regHasNull){
+  int addr1;
+  sqlite3VdbeAddOp2(v, OP_Integer, 0, regHasNull);
+  addr1 = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
+  sqlite3VdbeAddOp3(v, OP_Column, iCur, 0, regHasNull);
+  sqlite3VdbeChangeP5(v, OPFLAG_TYPEOFARG);
+  VdbeComment((v, "first_entry_in(%d)", iCur));
+  sqlite3VdbeJumpHere(v, addr1);
+}
+#endif
+
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** The argument is an IN operator with a list (not a subquery) on the
+** right-hand side.  Return TRUE if that list is constant.
+*/
+static int sqlite3InRhsIsConstant(Parse *pParse, Expr *pIn){
+  Expr *pLHS;
+  int res;
+  assert( !ExprHasProperty(pIn, EP_xIsSelect) );
+  pLHS = pIn->pLeft;
+  pIn->pLeft = 0;
+  res = sqlite3ExprIsConstant(pParse, pIn);
+  pIn->pLeft = pLHS;
+  return res;
+}
+#endif
+
+/*
+** This function is used by the implementation of the IN (...) operator.
+** The pX parameter is the expression on the RHS of the IN operator, which
+** might be either a list of expressions or a subquery.
+**
+** The job of this routine is to find or create a b-tree object that can
+** be used either to test for membership in the RHS set or to iterate through
+** all members of the RHS set, skipping duplicates.
+**
+** A cursor is opened on the b-tree object that is the RHS of the IN operator
+** and the *piTab parameter is set to the index of that cursor.
+**
+** The returned value of this function indicates the b-tree type, as follows:
+**
+**   IN_INDEX_ROWID      - The cursor was opened on a database table.
+**   IN_INDEX_INDEX_ASC  - The cursor was opened on an ascending index.
+**   IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
+**   IN_INDEX_EPH        - The cursor was opened on a specially created and
+**                         populated ephemeral table.
+**   IN_INDEX_NOOP       - No cursor was allocated.  The IN operator must be
+**                         implemented as a sequence of comparisons.
+**
+** An existing b-tree might be used if the RHS expression pX is a simple
+** subquery such as:
+**
+**     SELECT <column1>, <column2>... FROM <table>
+**
+** If the RHS of the IN operator is a list or a more complex subquery, then
+** an ephemeral table might need to be generated from the RHS and then
+** pX->iTable made to point to the ephemeral table instead of an
+** existing table.  In this case, the creation and initialization of the
+** ephemeral table might be put inside of a subroutine, the EP_Subrtn flag
+** will be set on pX and the pX->y.sub fields will be set to show where
+** the subroutine is coded.
+**
+** The inFlags parameter must contain, at a minimum, one of the bits
+** IN_INDEX_MEMBERSHIP or IN_INDEX_LOOP but not both.  If inFlags contains
+** IN_INDEX_MEMBERSHIP, then the generated table will be used for a fast
+** membership test.  When the IN_INDEX_LOOP bit is set, the IN index will
+** be used to loop over all values of the RHS of the IN operator.
+**
+** When IN_INDEX_LOOP is used (and the b-tree will be used to iterate
+** through the set members) then the b-tree must not contain duplicates.
+** An ephemeral table will be created unless the selected columns are guaranteed
+** to be unique - either because it is an INTEGER PRIMARY KEY or due to
+** a UNIQUE constraint or index.
+**
+** When IN_INDEX_MEMBERSHIP is used (and the b-tree will be used
+** for fast set membership tests) then an ephemeral table must
+** be used unless <columns> is a single INTEGER PRIMARY KEY column or an
+** index can be found with the specified <columns> as its left-most.
+**
+** If the IN_INDEX_NOOP_OK and IN_INDEX_MEMBERSHIP are both set and
+** if the RHS of the IN operator is a list (not a subquery) then this
+** routine might decide that creating an ephemeral b-tree for membership
+** testing is too expensive and return IN_INDEX_NOOP.  In that case, the
+** calling routine should implement the IN operator using a sequence
+** of Eq or Ne comparison operations.
+**
+** When the b-tree is being used for membership tests, the calling function
+** might need to know whether or not the RHS side of the IN operator
+** contains a NULL.  If prRhsHasNull is not a NULL pointer and
+** if there is any chance that the (...) might contain a NULL value at
+** runtime, then a register is allocated and the register number written
+** to *prRhsHasNull. If there is no chance that the (...) contains a
+** NULL value, then *prRhsHasNull is left unchanged.
+**
+** If a register is allocated and its location stored in *prRhsHasNull, then
+** the value in that register will be NULL if the b-tree contains one or more
+** NULL values, and it will be some non-NULL value if the b-tree contains no
+** NULL values.
+**
+** If the aiMap parameter is not NULL, it must point to an array containing
+** one element for each column returned by the SELECT statement on the RHS
+** of the IN(...) operator. The i'th entry of the array is populated with the
+** offset of the index column that matches the i'th column returned by the
+** SELECT. For example, if the expression and selected index are:
+**
+**   (?,?,?) IN (SELECT a, b, c FROM t1)
+**   CREATE INDEX i1 ON t1(b, c, a);
+**
+** then aiMap[] is populated with {2, 0, 1}.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+SQLITE_PRIVATE int sqlite3FindInIndex(
+  Parse *pParse,             /* Parsing context */
+  Expr *pX,                  /* The IN expression */
+  u32 inFlags,               /* IN_INDEX_LOOP, _MEMBERSHIP, and/or _NOOP_OK */
+  int *prRhsHasNull,         /* Register holding NULL status.  See notes */
+  int *aiMap,                /* Mapping from Index fields to RHS fields */
+  int *piTab                 /* OUT: index to use */
+){
+  Select *p;                            /* SELECT to the right of IN operator */
+  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
+  int iTab;                             /* Cursor of the RHS table */
+  int mustBeUnique;                     /* True if RHS must be unique */
+  Vdbe *v = sqlite3GetVdbe(pParse);     /* Virtual machine being coded */
+
+  assert( pX->op==TK_IN );
+  mustBeUnique = (inFlags & IN_INDEX_LOOP)!=0;
+  iTab = pParse->nTab++;
+
+  /* If the RHS of this IN(...) operator is a SELECT, and if it matters
+  ** whether or not the SELECT result contains NULL values, check whether
+  ** or not NULL is actually possible (it may not be, for example, due
+  ** to NOT NULL constraints in the schema). If no NULL values are possible,
+  ** set prRhsHasNull to 0 before continuing.  */
+  if( prRhsHasNull && ExprUseXSelect(pX) ){
+    int i;
+    ExprList *pEList = pX->x.pSelect->pEList;
+    for(i=0; i<pEList->nExpr; i++){
+      if( sqlite3ExprCanBeNull(pEList->a[i].pExpr) ) break;
+    }
+    if( i==pEList->nExpr ){
+      prRhsHasNull = 0;
+    }
+  }
+
+  /* Check to see if an existing table or index can be used to
+  ** satisfy the query.  This is preferable to generating a new
+  ** ephemeral table.  */
+  if( pParse->nErr==0 && (p = isCandidateForInOpt(pX))!=0 ){
+    sqlite3 *db = pParse->db;              /* Database connection */
+    Table *pTab;                           /* Table <table>. */
+    int iDb;                               /* Database idx for pTab */
+    ExprList *pEList = p->pEList;
+    int nExpr = pEList->nExpr;
+
+    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
+    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
+    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
+    pTab = p->pSrc->a[0].pSTab;
+
+    /* Code an OP_Transaction and OP_TableLock for <table>. */
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    assert( iDb>=0 && iDb<SQLITE_MAX_DB );
+    sqlite3CodeVerifySchema(pParse, iDb);
+    sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+
+    assert(v);  /* sqlite3GetVdbe() has always been previously called */
+    if( nExpr==1 && pEList->a[0].pExpr->iColumn<0 ){
+      /* The "x IN (SELECT rowid FROM table)" case */
+      int iAddr = sqlite3VdbeAddOp0(v, OP_Once);
+      VdbeCoverage(v);
+
+      sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
+      eType = IN_INDEX_ROWID;
+      ExplainQueryPlan((pParse, 0,
+            "USING ROWID SEARCH ON TABLE %s FOR IN-OPERATOR",pTab->zName));
+      sqlite3VdbeJumpHere(v, iAddr);
+    }else{
+      Index *pIdx;                         /* Iterator variable */
+      int affinity_ok = 1;
+      int i;
+
+      /* Check that the affinity that will be used to perform each
+      ** comparison is the same as the affinity of each column in table
+      ** on the RHS of the IN operator.  If it not, it is not possible to
+      ** use any index of the RHS table.  */
+      for(i=0; i<nExpr && affinity_ok; i++){
+        Expr *pLhs = sqlite3VectorFieldSubexpr(pX->pLeft, i);
+        int iCol = pEList->a[i].pExpr->iColumn;
+        char idxaff = sqlite3TableColumnAffinity(pTab,iCol); /* RHS table */
+        char cmpaff = sqlite3CompareAffinity(pLhs, idxaff);
+        testcase( cmpaff==SQLITE_AFF_BLOB );
+        testcase( cmpaff==SQLITE_AFF_TEXT );
+        switch( cmpaff ){
+          case SQLITE_AFF_BLOB:
+            break;
+          case SQLITE_AFF_TEXT:
+            /* sqlite3CompareAffinity() only returns TEXT if one side or the
+            ** other has no affinity and the other side is TEXT.  Hence,
+            ** the only way for cmpaff to be TEXT is for idxaff to be TEXT
+            ** and for the term on the LHS of the IN to have no affinity. */
+            assert( idxaff==SQLITE_AFF_TEXT );
+            break;
+          default:
+            affinity_ok = sqlite3IsNumericAffinity(idxaff);
+        }
+      }
+
+      if( affinity_ok ){
+        /* Search for an existing index that will work for this IN operator */
+        for(pIdx=pTab->pIndex; pIdx && eType==0; pIdx=pIdx->pNext){
+          Bitmask colUsed;      /* Columns of the index used */
+          Bitmask mCol;         /* Mask for the current column */
+          if( pIdx->nColumn<nExpr ) continue;
+          if( pIdx->pPartIdxWhere!=0 ) continue;
+          /* Maximum nColumn is BMS-2, not BMS-1, so that we can compute
+          ** BITMASK(nExpr) without overflowing */
+          testcase( pIdx->nColumn==BMS-2 );
+          testcase( pIdx->nColumn==BMS-1 );
+          if( pIdx->nColumn>=BMS-1 ) continue;
+          if( mustBeUnique ){
+            if( pIdx->nKeyCol>nExpr
+             ||(pIdx->nColumn>nExpr && !IsUniqueIndex(pIdx))
+            ){
+              continue;  /* This index is not unique over the IN RHS columns */
+            }
+          }
+
+          colUsed = 0;   /* Columns of index used so far */
+          for(i=0; i<nExpr; i++){
+            Expr *pLhs = sqlite3VectorFieldSubexpr(pX->pLeft, i);
+            Expr *pRhs = pEList->a[i].pExpr;
+            CollSeq *pReq = sqlite3BinaryCompareCollSeq(pParse, pLhs, pRhs);
+            int j;
+
+            for(j=0; j<nExpr; j++){
+              if( pIdx->aiColumn[j]!=pRhs->iColumn ) continue;
+              assert( pIdx->azColl[j] );
+              if( pReq!=0 && sqlite3StrICmp(pReq->zName, pIdx->azColl[j])!=0 ){
+                continue;
+              }
+              break;
+            }
+            if( j==nExpr ) break;
+            mCol = MASKBIT(j);
+            if( mCol & colUsed ) break; /* Each column used only once */
+            colUsed |= mCol;
+            if( aiMap ) aiMap[i] = j;
+          }
+
+          assert( nExpr>0 && nExpr<BMS );
+          assert( i==nExpr || colUsed!=(MASKBIT(nExpr)-1) );
+          if( colUsed==(MASKBIT(nExpr)-1) ){
+            /* If we reach this point, that means the index pIdx is usable */
+            int iAddr = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+            ExplainQueryPlan((pParse, 0,
+                              "USING INDEX %s FOR IN-OPERATOR",pIdx->zName));
+            sqlite3VdbeAddOp3(v, OP_OpenRead, iTab, pIdx->tnum, iDb);
+            sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+            VdbeComment((v, "%s", pIdx->zName));
+            assert( IN_INDEX_INDEX_DESC == IN_INDEX_INDEX_ASC+1 );
+            eType = IN_INDEX_INDEX_ASC + pIdx->aSortOrder[0];
+
+            if( prRhsHasNull ){
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+              i64 mask = (1<<nExpr)-1;
+              sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed,
+                  iTab, 0, 0, (u8*)&mask, P4_INT64);
+#endif
+              *prRhsHasNull = ++pParse->nMem;
+              if( nExpr==1 ){
+                sqlite3SetHasNullFlag(v, iTab, *prRhsHasNull);
+              }
+            }
+            sqlite3VdbeJumpHere(v, iAddr);
+          }
+        } /* End loop over indexes */
+      } /* End if( affinity_ok ) */
+    } /* End if not an rowid index */
+  } /* End attempt to optimize using an index */
+
+  /* If no preexisting index is available for the IN clause
+  ** and IN_INDEX_NOOP is an allowed reply
+  ** and the RHS of the IN operator is a list, not a subquery
+  ** and the RHS is not constant or has two or fewer terms,
+  ** then it is not worth creating an ephemeral table to evaluate
+  ** the IN operator so return IN_INDEX_NOOP.
+  */
+  if( eType==0
+   && (inFlags & IN_INDEX_NOOP_OK)
+   && ExprUseXList(pX)
+   && (!sqlite3InRhsIsConstant(pParse,pX) || pX->x.pList->nExpr<=2)
+  ){
+    pParse->nTab--;  /* Back out the allocation of the unused cursor */
+    iTab = -1;       /* Cursor is not allocated */
+    eType = IN_INDEX_NOOP;
+  }
+
+  if( eType==0 ){
+    /* Could not find an existing table or index to use as the RHS b-tree.
+    ** We will have to generate an ephemeral table to do the job.
+    */
+    u32 savedNQueryLoop = pParse->nQueryLoop;
+    int rMayHaveNull = 0;
+    eType = IN_INDEX_EPH;
+    if( inFlags & IN_INDEX_LOOP ){
+      pParse->nQueryLoop = 0;
+    }else if( prRhsHasNull ){
+      *prRhsHasNull = rMayHaveNull = ++pParse->nMem;
+    }
+    assert( pX->op==TK_IN );
+    sqlite3CodeRhsOfIN(pParse, pX, iTab);
+    if( rMayHaveNull ){
+      sqlite3SetHasNullFlag(v, iTab, rMayHaveNull);
+    }
+    pParse->nQueryLoop = savedNQueryLoop;
+  }
+
+  if( aiMap && eType!=IN_INDEX_INDEX_ASC && eType!=IN_INDEX_INDEX_DESC ){
+    int i, n;
+    n = sqlite3ExprVectorSize(pX->pLeft);
+    for(i=0; i<n; i++) aiMap[i] = i;
+  }
+  *piTab = iTab;
+  return eType;
+}
+#endif
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Argument pExpr is an (?, ?...) IN(...) expression. This
+** function allocates and returns a nul-terminated string containing
+** the affinities to be used for each column of the comparison.
+**
+** It is the responsibility of the caller to ensure that the returned
+** string is eventually freed using sqlite3DbFree().
+*/
+static char *exprINAffinity(Parse *pParse, const Expr *pExpr){
+  Expr *pLeft = pExpr->pLeft;
+  int nVal = sqlite3ExprVectorSize(pLeft);
+  Select *pSelect = ExprUseXSelect(pExpr) ? pExpr->x.pSelect : 0;
+  char *zRet;
+
+  assert( pExpr->op==TK_IN );
+  zRet = sqlite3DbMallocRaw(pParse->db, nVal+1);
+  if( zRet ){
+    int i;
+    for(i=0; i<nVal; i++){
+      Expr *pA = sqlite3VectorFieldSubexpr(pLeft, i);
+      char a = sqlite3ExprAffinity(pA);
+      if( pSelect ){
+        zRet[i] = sqlite3CompareAffinity(pSelect->pEList->a[i].pExpr, a);
+      }else{
+        zRet[i] = a;
+      }
+    }
+    zRet[nVal] = '\0';
+  }
+  return zRet;
+}
+#endif
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Load the Parse object passed as the first argument with an error
+** message of the form:
+**
+**   "sub-select returns N columns - expected M"
+*/
+SQLITE_PRIVATE void sqlite3SubselectError(Parse *pParse, int nActual, int nExpect){
+  if( pParse->nErr==0 ){
+    const char *zFmt = "sub-select returns %d columns - expected %d";
+    sqlite3ErrorMsg(pParse, zFmt, nActual, nExpect);
+  }
+}
+#endif
+
+/*
+** Expression pExpr is a vector that has been used in a context where
+** it is not permitted. If pExpr is a sub-select vector, this routine
+** loads the Parse object with a message of the form:
+**
+**   "sub-select returns N columns - expected 1"
+**
+** Or, if it is a regular scalar vector:
+**
+**   "row value misused"
+*/
+SQLITE_PRIVATE void sqlite3VectorErrorMsg(Parse *pParse, Expr *pExpr){
+#ifndef SQLITE_OMIT_SUBQUERY
+  if( ExprUseXSelect(pExpr) ){
+    sqlite3SubselectError(pParse, pExpr->x.pSelect->pEList->nExpr, 1);
+  }else
+#endif
+  {
+    sqlite3ErrorMsg(pParse, "row value misused");
+  }
+}
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Scan all previously generated bytecode looking for an OP_BeginSubrtn
+** that is compatible with pExpr.  If found, add the y.sub values
+** to pExpr and return true.  If not found, return false.
+*/
+static int findCompatibleInRhsSubrtn(
+  Parse *pParse,          /* Parsing context */
+  Expr *pExpr,            /* IN operator with RHS that we want to reuse */
+  SubrtnSig *pNewSig      /* Signature for the IN operator */
+){
+  VdbeOp *pOp, *pEnd;
+  SubrtnSig *pSig;
+  Vdbe *v;
+
+  if( pNewSig==0 ) return 0;
+  if( (pParse->mSubrtnSig & (1<<(pNewSig->selId&7)))==0 ) return 0;
+  assert( pExpr->op==TK_IN );
+  assert( !ExprUseYSub(pExpr) );
+  assert( ExprUseXSelect(pExpr) );
+  assert( pExpr->x.pSelect!=0 );
+  assert( (pExpr->x.pSelect->selFlags & SF_All)==0 );
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  pOp = sqlite3VdbeGetOp(v, 1);
+  pEnd = sqlite3VdbeGetLastOp(v);
+  for(; pOp<pEnd; pOp++){
+    if( pOp->p4type!=P4_SUBRTNSIG ) continue;
+    assert( pOp->opcode==OP_BeginSubrtn );
+    pSig = pOp->p4.pSubrtnSig;
+    assert( pSig!=0 );
+    if( !pSig->bComplete ) continue;
+    if( pNewSig->selId!=pSig->selId ) continue;
+    if( strcmp(pNewSig->zAff,pSig->zAff)!=0 ) continue;
+    pExpr->y.sub.iAddr = pSig->iAddr;
+    pExpr->y.sub.regReturn = pSig->regReturn;
+    pExpr->iTable = pSig->iTable;
+    ExprSetProperty(pExpr, EP_Subrtn);
+    return 1;
+  }
+  return 0;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code that will construct an ephemeral table containing all terms
+** in the RHS of an IN operator.  The IN operator can be in either of two
+** forms:
+**
+**     x IN (4,5,11)              -- IN operator with list on right-hand side
+**     x IN (SELECT a FROM b)     -- IN operator with subquery on the right
+**
+** The pExpr parameter is the IN operator.  The cursor number for the
+** constructed ephemeral table is returned.  The first time the ephemeral
+** table is computed, the cursor number is also stored in pExpr->iTable,
+** however the cursor number returned might not be the same, as it might
+** have been duplicated using OP_OpenDup.
+**
+** If the LHS expression ("x" in the examples) is a column value, or
+** the SELECT statement returns a column value, then the affinity of that
+** column is used to build the index keys. If both 'x' and the
+** SELECT... statement are columns, then numeric affinity is used
+** if either column has NUMERIC or INTEGER affinity. If neither
+** 'x' nor the SELECT... statement are columns, then numeric affinity
+** is used.
+*/
+SQLITE_PRIVATE void sqlite3CodeRhsOfIN(
+  Parse *pParse,          /* Parsing context */
+  Expr *pExpr,            /* The IN operator */
+  int iTab                /* Use this cursor number */
+){
+  int addrOnce = 0;           /* Address of the OP_Once instruction at top */
+  int addr;                   /* Address of OP_OpenEphemeral instruction */
+  Expr *pLeft;                /* the LHS of the IN operator */
+  KeyInfo *pKeyInfo = 0;      /* Key information */
+  int nVal;                   /* Size of vector pLeft */
+  Vdbe *v;                    /* The prepared statement under construction */
+  SubrtnSig *pSig = 0;        /* Signature for this subroutine */
+
+  v = pParse->pVdbe;
+  assert( v!=0 );
+
+  /* The evaluation of the IN must be repeated every time it
+  ** is encountered if any of the following is true:
+  **
+  **    *  The right-hand side is a correlated subquery
+  **    *  The right-hand side is an expression list containing variables
+  **    *  We are inside a trigger
+  **
+  ** If all of the above are false, then we can compute the RHS just once
+  ** and reuse it many names.
+  */
+  if( !ExprHasProperty(pExpr, EP_VarSelect) && pParse->iSelfTab==0 ){
+    /* Reuse of the RHS is allowed
+    **
+    ** Compute a signature for the RHS of the IN operator to facility
+    ** finding and reusing prior instances of the same IN operator.
+    */
+    assert( !ExprUseXSelect(pExpr) || pExpr->x.pSelect!=0 );
+    if( ExprUseXSelect(pExpr) && (pExpr->x.pSelect->selFlags & SF_All)==0 ){
+      pSig = sqlite3DbMallocRawNN(pParse->db, sizeof(pSig[0]));
+      if( pSig ){
+        pSig->selId = pExpr->x.pSelect->selId;
+        pSig->zAff = exprINAffinity(pParse, pExpr);
+      }
+    }
+
+    /* Check to see if there is a prior materialization of the RHS of
+    ** this IN operator.  If there is, then make use of that prior
+    ** materialization rather than recomputing it.
+    */
+    if( ExprHasProperty(pExpr, EP_Subrtn)
+     || findCompatibleInRhsSubrtn(pParse, pExpr, pSig)
+    ){
+      addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+      if( ExprUseXSelect(pExpr) ){
+        ExplainQueryPlan((pParse, 0, "REUSE LIST SUBQUERY %d",
+              pExpr->x.pSelect->selId));
+      }
+      assert( ExprUseYSub(pExpr) );
+      sqlite3VdbeAddOp2(v, OP_Gosub, pExpr->y.sub.regReturn,
+                        pExpr->y.sub.iAddr);
+      assert( iTab!=pExpr->iTable );
+      sqlite3VdbeAddOp2(v, OP_OpenDup, iTab, pExpr->iTable);
+      sqlite3VdbeJumpHere(v, addrOnce);
+      if( pSig ){
+        sqlite3DbFree(pParse->db, pSig->zAff);
+        sqlite3DbFree(pParse->db, pSig);
+      }
+      return;
+    }
+
+    /* Begin coding the subroutine */
+    assert( !ExprUseYWin(pExpr) );
+    ExprSetProperty(pExpr, EP_Subrtn);
+    assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+    pExpr->y.sub.regReturn = ++pParse->nMem;
+    pExpr->y.sub.iAddr =
+      sqlite3VdbeAddOp2(v, OP_BeginSubrtn, 0, pExpr->y.sub.regReturn) + 1;
+    if( pSig ){
+      pSig->bComplete = 0;
+      pSig->iAddr = pExpr->y.sub.iAddr;
+      pSig->regReturn = pExpr->y.sub.regReturn;
+      pSig->iTable = iTab;
+      pParse->mSubrtnSig = 1 << (pSig->selId&7);
+      sqlite3VdbeChangeP4(v, -1, (const char*)pSig, P4_SUBRTNSIG);
+    }
+    addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+  }
+
+  /* Check to see if this is a vector IN operator */
+  pLeft = pExpr->pLeft;
+  nVal = sqlite3ExprVectorSize(pLeft);
+
+  /* Construct the ephemeral table that will contain the content of
+  ** RHS of the IN operator.
+  */
+  pExpr->iTable = iTab;
+  addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pExpr->iTable, nVal);
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+  if( ExprUseXSelect(pExpr) ){
+    VdbeComment((v, "Result of SELECT %u", pExpr->x.pSelect->selId));
+  }else{
+    VdbeComment((v, "RHS of IN operator"));
+  }
+#endif
+  pKeyInfo = sqlite3KeyInfoAlloc(pParse->db, nVal, 1);
+
+  if( ExprUseXSelect(pExpr) ){
+    /* Case 1:     expr IN (SELECT ...)
+    **
+    ** Generate code to write the results of the select into the temporary
+    ** table allocated and opened above.
+    */
+    Select *pSelect = pExpr->x.pSelect;
+    ExprList *pEList = pSelect->pEList;
+
+    ExplainQueryPlan((pParse, 1, "%sLIST SUBQUERY %d",
+        addrOnce?"":"CORRELATED ", pSelect->selId
+    ));
+    /* If the LHS and RHS of the IN operator do not match, that
+    ** error will have been caught long before we reach this point. */
+    if( ALWAYS(pEList->nExpr==nVal) ){
+      Select *pCopy;
+      SelectDest dest;
+      int i;
+      int rc;
+      int addrBloom = 0;
+      sqlite3SelectDestInit(&dest, SRT_Set, iTab);
+      dest.zAffSdst = exprINAffinity(pParse, pExpr);
+      pSelect->iLimit = 0;
+      if( addrOnce && OptimizationEnabled(pParse->db, SQLITE_BloomFilter) ){
+        int regBloom = ++pParse->nMem;
+        addrBloom = sqlite3VdbeAddOp2(v, OP_Blob, 10000, regBloom);
+        VdbeComment((v, "Bloom filter"));
+        dest.iSDParm2 = regBloom;
+      }
+      testcase( pSelect->selFlags & SF_Distinct );
+      testcase( pKeyInfo==0 ); /* Caused by OOM in sqlite3KeyInfoAlloc() */
+      pCopy = sqlite3SelectDup(pParse->db, pSelect, 0);
+      rc = pParse->db->mallocFailed ? 1 :sqlite3Select(pParse, pCopy, &dest);
+      sqlite3SelectDelete(pParse->db, pCopy);
+      sqlite3DbFree(pParse->db, dest.zAffSdst);
+      if( addrBloom ){
+        sqlite3VdbeGetOp(v, addrOnce)->p3 = dest.iSDParm2;
+        if( dest.iSDParm2==0 ){
+          sqlite3VdbeChangeToNoop(v, addrBloom);
+        }else{
+          sqlite3VdbeGetOp(v, addrOnce)->p3 = dest.iSDParm2;
+        }
+      }
+      if( rc ){
+        sqlite3KeyInfoUnref(pKeyInfo);
+        return;
+      }
+      assert( pKeyInfo!=0 ); /* OOM will cause exit after sqlite3Select() */
+      assert( pEList!=0 );
+      assert( pEList->nExpr>0 );
+      assert( sqlite3KeyInfoIsWriteable(pKeyInfo) );
+      for(i=0; i<nVal; i++){
+        Expr *p = sqlite3VectorFieldSubexpr(pLeft, i);
+        pKeyInfo->aColl[i] = sqlite3BinaryCompareCollSeq(
+            pParse, p, pEList->a[i].pExpr
+        );
+      }
+    }
+  }else if( ALWAYS(pExpr->x.pList!=0) ){
+    /* Case 2:     expr IN (exprlist)
+    **
+    ** For each expression, build an index key from the evaluation and
+    ** store it in the temporary table. If <expr> is a column, then use
+    ** that columns affinity when building index keys. If <expr> is not
+    ** a column, use numeric affinity.
+    */
+    char affinity;            /* Affinity of the LHS of the IN */
+    int i;
+    ExprList *pList = pExpr->x.pList;
+    struct ExprList_item *pItem;
+    int r1, r2;
+    affinity = sqlite3ExprAffinity(pLeft);
+    if( affinity<=SQLITE_AFF_NONE ){
+      affinity = SQLITE_AFF_BLOB;
+    }else if( affinity==SQLITE_AFF_REAL ){
+      affinity = SQLITE_AFF_NUMERIC;
+    }
+    if( pKeyInfo ){
+      assert( sqlite3KeyInfoIsWriteable(pKeyInfo) );
+      pKeyInfo->aColl[0] = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+    }
+
+    /* Loop through each expression in <exprlist>. */
+    r1 = sqlite3GetTempReg(pParse);
+    r2 = sqlite3GetTempReg(pParse);
+    for(i=pList->nExpr, pItem=pList->a; i>0; i--, pItem++){
+      Expr *pE2 = pItem->pExpr;
+
+      /* If the expression is not constant then we will need to
+      ** disable the test that was generated above that makes sure
+      ** this code only executes once.  Because for a non-constant
+      ** expression we need to rerun this code each time.
+      */
+      if( addrOnce && !sqlite3ExprIsConstant(pParse, pE2) ){
+        sqlite3VdbeChangeToNoop(v, addrOnce-1);
+        sqlite3VdbeChangeToNoop(v, addrOnce);
+        ExprClearProperty(pExpr, EP_Subrtn);
+        addrOnce = 0;
+      }
+
+      /* Evaluate the expression and insert it into the temp table */
+      sqlite3ExprCode(pParse, pE2, r1);
+      sqlite3VdbeAddOp4(v, OP_MakeRecord, r1, 1, r2, &affinity, 1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iTab, r2, r1, 1);
+    }
+    sqlite3ReleaseTempReg(pParse, r1);
+    sqlite3ReleaseTempReg(pParse, r2);
+  }
+  if( pSig ) pSig->bComplete = 1;
+  if( pKeyInfo ){
+    sqlite3VdbeChangeP4(v, addr, (void *)pKeyInfo, P4_KEYINFO);
+  }
+  if( addrOnce ){
+    sqlite3VdbeAddOp1(v, OP_NullRow, iTab);
+    sqlite3VdbeJumpHere(v, addrOnce);
+    /* Subroutine return */
+    assert( ExprUseYSub(pExpr) );
+    assert( sqlite3VdbeGetOp(v,pExpr->y.sub.iAddr-1)->opcode==OP_BeginSubrtn
+            || pParse->nErr );
+    sqlite3VdbeAddOp3(v, OP_Return, pExpr->y.sub.regReturn,
+                      pExpr->y.sub.iAddr, 1);
+    VdbeCoverage(v);
+    sqlite3ClearTempRegCache(pParse);
+  }
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+/*
+** Generate code for scalar subqueries used as a subquery expression
+** or EXISTS operator:
+**
+**     (SELECT a FROM b)          -- subquery
+**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
+**
+** The pExpr parameter is the SELECT or EXISTS operator to be coded.
+**
+** Return the register that holds the result.  For a multi-column SELECT,
+** the result is stored in a contiguous array of registers and the
+** return value is the register of the left-most result column.
+** Return 0 if an error occurs.
+*/
+#ifndef SQLITE_OMIT_SUBQUERY
+SQLITE_PRIVATE int sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
+  int addrOnce = 0;           /* Address of OP_Once at top of subroutine */
+  int rReg = 0;               /* Register storing resulting */
+  Select *pSel;               /* SELECT statement to encode */
+  SelectDest dest;            /* How to deal with SELECT result */
+  int nReg;                   /* Registers to allocate */
+  Expr *pLimit;               /* New limit expression */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrExplain;            /* Address of OP_Explain instruction */
+#endif
+
+  Vdbe *v = pParse->pVdbe;
+  assert( v!=0 );
+  if( pParse->nErr ) return 0;
+  testcase( pExpr->op==TK_EXISTS );
+  testcase( pExpr->op==TK_SELECT );
+  assert( pExpr->op==TK_EXISTS || pExpr->op==TK_SELECT );
+  assert( ExprUseXSelect(pExpr) );
+  pSel = pExpr->x.pSelect;
+
+  /* If this routine has already been coded, then invoke it as a
+  ** subroutine. */
+  if( ExprHasProperty(pExpr, EP_Subrtn) ){
+    ExplainQueryPlan((pParse, 0, "REUSE SUBQUERY %d", pSel->selId));
+    assert( ExprUseYSub(pExpr) );
+    sqlite3VdbeAddOp2(v, OP_Gosub, pExpr->y.sub.regReturn,
+                      pExpr->y.sub.iAddr);
+    return pExpr->iTable;
+  }
+
+  /* Begin coding the subroutine */
+  assert( !ExprUseYWin(pExpr) );
+  assert( !ExprHasProperty(pExpr, EP_Reduced|EP_TokenOnly) );
+  ExprSetProperty(pExpr, EP_Subrtn);
+  pExpr->y.sub.regReturn = ++pParse->nMem;
+  pExpr->y.sub.iAddr =
+    sqlite3VdbeAddOp2(v, OP_BeginSubrtn, 0, pExpr->y.sub.regReturn) + 1;
+
+  /* The evaluation of the EXISTS/SELECT must be repeated every time it
+  ** is encountered if any of the following is true:
+  **
+  **    *  The right-hand side is a correlated subquery
+  **    *  The right-hand side is an expression list containing variables
+  **    *  We are inside a trigger
+  **
+  ** If all of the above are false, then we can run this code just once
+  ** save the results, and reuse the same result on subsequent invocations.
+  */
+  if( !ExprHasProperty(pExpr, EP_VarSelect) ){
+    addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+  }
+
+  /* For a SELECT, generate code to put the values for all columns of
+  ** the first row into an array of registers and return the index of
+  ** the first register.
+  **
+  ** If this is an EXISTS, write an integer 0 (not exists) or 1 (exists)
+  ** into a register and return that register number.
+  **
+  ** In both cases, the query is augmented with "LIMIT 1".  Any
+  ** preexisting limit is discarded in place of the new LIMIT 1.
+  */
+  ExplainQueryPlan2(addrExplain, (pParse, 1, "%sSCALAR SUBQUERY %d",
+        addrOnce?"":"CORRELATED ", pSel->selId));
+  sqlite3VdbeScanStatusCounters(v, addrExplain, addrExplain, -1);
+  nReg = pExpr->op==TK_SELECT ? pSel->pEList->nExpr : 1;
+  sqlite3SelectDestInit(&dest, 0, pParse->nMem+1);
+  pParse->nMem += nReg;
+  if( pExpr->op==TK_SELECT ){
+    dest.eDest = SRT_Mem;
+    dest.iSdst = dest.iSDParm;
+    dest.nSdst = nReg;
+    sqlite3VdbeAddOp3(v, OP_Null, 0, dest.iSDParm, dest.iSDParm+nReg-1);
+    VdbeComment((v, "Init subquery result"));
+  }else{
+    dest.eDest = SRT_Exists;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iSDParm);
+    VdbeComment((v, "Init EXISTS result"));
+  }
+  if( pSel->pLimit ){
+    /* The subquery already has a limit.  If the pre-existing limit is X
+    ** then make the new limit X<>0 so that the new limit is either 1 or 0 */
+    sqlite3 *db = pParse->db;
+    pLimit = sqlite3Expr(db, TK_INTEGER, "0");
+    if( pLimit ){
+      pLimit->affExpr = SQLITE_AFF_NUMERIC;
+      pLimit = sqlite3PExpr(pParse, TK_NE,
+                            sqlite3ExprDup(db, pSel->pLimit->pLeft, 0), pLimit);
+    }
+    sqlite3ExprDeferredDelete(pParse, pSel->pLimit->pLeft);
+    pSel->pLimit->pLeft = pLimit;
+  }else{
+    /* If there is no pre-existing limit add a limit of 1 */
+    pLimit = sqlite3Expr(pParse->db, TK_INTEGER, "1");
+    pSel->pLimit = sqlite3PExpr(pParse, TK_LIMIT, pLimit, 0);
+  }
+  pSel->iLimit = 0;
+  if( sqlite3Select(pParse, pSel, &dest) ){
+    pExpr->op2 = pExpr->op;
+    pExpr->op = TK_ERROR;
+    return 0;
+  }
+  pExpr->iTable = rReg = dest.iSDParm;
+  ExprSetVVAProperty(pExpr, EP_NoReduce);
+  if( addrOnce ){
+    sqlite3VdbeJumpHere(v, addrOnce);
+  }
+  sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1);
+
+  /* Subroutine return */
+  assert( ExprUseYSub(pExpr) );
+  assert( sqlite3VdbeGetOp(v,pExpr->y.sub.iAddr-1)->opcode==OP_BeginSubrtn
+          || pParse->nErr );
+  sqlite3VdbeAddOp3(v, OP_Return, pExpr->y.sub.regReturn,
+                    pExpr->y.sub.iAddr, 1);
+  VdbeCoverage(v);
+  sqlite3ClearTempRegCache(pParse);
+  return rReg;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Expr pIn is an IN(...) expression. This function checks that the
+** sub-select on the RHS of the IN() operator has the same number of
+** columns as the vector on the LHS. Or, if the RHS of the IN() is not
+** a sub-query, that the LHS is a vector of size 1.
+*/
+SQLITE_PRIVATE int sqlite3ExprCheckIN(Parse *pParse, Expr *pIn){
+  int nVector = sqlite3ExprVectorSize(pIn->pLeft);
+  if( ExprUseXSelect(pIn) && !pParse->db->mallocFailed ){
+    if( nVector!=pIn->x.pSelect->pEList->nExpr ){
+      sqlite3SubselectError(pParse, pIn->x.pSelect->pEList->nExpr, nVector);
+      return 1;
+    }
+  }else if( nVector!=1 ){
+    sqlite3VectorErrorMsg(pParse, pIn->pLeft);
+    return 1;
+  }
+  return 0;
+}
+#endif
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code for an IN expression.
+**
+**      x IN (SELECT ...)
+**      x IN (value, value, ...)
+**
+** The left-hand side (LHS) is a scalar or vector expression.  The
+** right-hand side (RHS) is an array of zero or more scalar values, or a
+** subquery.  If the RHS is a subquery, the number of result columns must
+** match the number of columns in the vector on the LHS.  If the RHS is
+** a list of values, the LHS must be a scalar.
+**
+** The IN operator is true if the LHS value is contained within the RHS.
+** The result is false if the LHS is definitely not in the RHS.  The
+** result is NULL if the presence of the LHS in the RHS cannot be
+** determined due to NULLs.
+**
+** This routine generates code that jumps to destIfFalse if the LHS is not
+** contained within the RHS.  If due to NULLs we cannot determine if the LHS
+** is contained in the RHS then jump to destIfNull.  If the LHS is contained
+** within the RHS then fall through.
+**
+** See the separate in-operator.md documentation file in the canonical
+** SQLite source tree for additional information.
+*/
+static void sqlite3ExprCodeIN(
+  Parse *pParse,        /* Parsing and code generating context */
+  Expr *pExpr,          /* The IN expression */
+  int destIfFalse,      /* Jump here if LHS is not contained in the RHS */
+  int destIfNull        /* Jump here if the results are unknown due to NULLs */
+){
+  int rRhsHasNull = 0;  /* Register that is true if RHS contains NULL values */
+  int eType;            /* Type of the RHS */
+  int rLhs;             /* Register(s) holding the LHS values */
+  int rLhsOrig;         /* LHS values prior to reordering by aiMap[] */
+  Vdbe *v;              /* Statement under construction */
+  int *aiMap = 0;       /* Map from vector field to index column */
+  char *zAff = 0;       /* Affinity string for comparisons */
+  int nVector;          /* Size of vectors for this IN operator */
+  int iDummy;           /* Dummy parameter to exprCodeVector() */
+  Expr *pLeft;          /* The LHS of the IN operator */
+  int i;                /* loop counter */
+  int destStep2;        /* Where to jump when NULLs seen in step 2 */
+  int destStep6 = 0;    /* Start of code for Step 6 */
+  int addrTruthOp;      /* Address of opcode that determines the IN is true */
+  int destNotNull;      /* Jump here if a comparison is not true in step 6 */
+  int addrTop;          /* Top of the step-6 loop */
+  int iTab = 0;         /* Index to use */
+  u8 okConstFactor = pParse->okConstFactor;
+
+  assert( !ExprHasVVAProperty(pExpr,EP_Immutable) );
+  pLeft = pExpr->pLeft;
+  if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
+  zAff = exprINAffinity(pParse, pExpr);
+  nVector = sqlite3ExprVectorSize(pExpr->pLeft);
+  aiMap = (int*)sqlite3DbMallocZero(pParse->db, nVector*sizeof(int));
+  if( pParse->db->mallocFailed ) goto sqlite3ExprCodeIN_oom_error;
+
+  /* Attempt to compute the RHS. After this step, if anything other than
+  ** IN_INDEX_NOOP is returned, the table opened with cursor iTab
+  ** contains the values that make up the RHS. If IN_INDEX_NOOP is returned,
+  ** the RHS has not yet been coded.  */
+  v = pParse->pVdbe;
+  assert( v!=0 );       /* OOM detected prior to this routine */
+  VdbeNoopComment((v, "begin IN expr"));
+  eType = sqlite3FindInIndex(pParse, pExpr,
+                             IN_INDEX_MEMBERSHIP | IN_INDEX_NOOP_OK,
+                             destIfFalse==destIfNull ? 0 : &rRhsHasNull,
+                             aiMap, &iTab);
+
+  assert( pParse->nErr || nVector==1 || eType==IN_INDEX_EPH
+       || eType==IN_INDEX_INDEX_ASC || eType==IN_INDEX_INDEX_DESC
+  );
+#ifdef SQLITE_DEBUG
+  /* Confirm that aiMap[] contains nVector integer values between 0 and
+  ** nVector-1. */
+  for(i=0; i<nVector; i++){
+    int j, cnt;
+    for(cnt=j=0; j<nVector; j++) if( aiMap[j]==i ) cnt++;
+    assert( cnt==1 );
+  }
+#endif
+
+  /* Code the LHS, the <expr> from "<expr> IN (...)". If the LHS is a
+  ** vector, then it is stored in an array of nVector registers starting
+  ** at r1.
+  **
+  ** sqlite3FindInIndex() might have reordered the fields of the LHS vector
+  ** so that the fields are in the same order as an existing index.   The
+  ** aiMap[] array contains a mapping from the original LHS field order to
+  ** the field order that matches the RHS index.
+  **
+  ** Avoid factoring the LHS of the IN(...) expression out of the loop,
+  ** even if it is constant, as OP_Affinity may be used on the register
+  ** by code generated below.  */
+  assert( pParse->okConstFactor==okConstFactor );
+  pParse->okConstFactor = 0;
+  rLhsOrig = exprCodeVector(pParse, pLeft, &iDummy);
+  pParse->okConstFactor = okConstFactor;
+  for(i=0; i<nVector && aiMap[i]==i; i++){} /* Are LHS fields reordered? */
+  if( i==nVector ){
+    /* LHS fields are not reordered */
+    rLhs = rLhsOrig;
+  }else{
+    /* Need to reorder the LHS fields according to aiMap */
+    rLhs = sqlite3GetTempRange(pParse, nVector);
+    for(i=0; i<nVector; i++){
+      sqlite3VdbeAddOp3(v, OP_Copy, rLhsOrig+i, rLhs+aiMap[i], 0);
+    }
+  }
+
+  /* If sqlite3FindInIndex() did not find or create an index that is
+  ** suitable for evaluating the IN operator, then evaluate using a
+  ** sequence of comparisons.
+  **
+  ** This is step (1) in the in-operator.md optimized algorithm.
+  */
+  if( eType==IN_INDEX_NOOP ){
+    ExprList *pList;
+    CollSeq *pColl;
+    int labelOk = sqlite3VdbeMakeLabel(pParse);
+    int r2, regToFree;
+    int regCkNull = 0;
+    int ii;
+    assert( ExprUseXList(pExpr) );
+    pList = pExpr->x.pList;
+    pColl = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
+    if( destIfNull!=destIfFalse ){
+      regCkNull = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_BitAnd, rLhs, rLhs, regCkNull);
+    }
+    for(ii=0; ii<pList->nExpr; ii++){
+      r2 = sqlite3ExprCodeTemp(pParse, pList->a[ii].pExpr, ®ToFree);
+      if( regCkNull && sqlite3ExprCanBeNull(pList->a[ii].pExpr) ){
+        sqlite3VdbeAddOp3(v, OP_BitAnd, regCkNull, r2, regCkNull);
+      }
+      sqlite3ReleaseTempReg(pParse, regToFree);
+      if( ii<pList->nExpr-1 || destIfNull!=destIfFalse ){
+        int op = rLhs!=r2 ? OP_Eq : OP_NotNull;
+        sqlite3VdbeAddOp4(v, op, rLhs, labelOk, r2,
+                          (void*)pColl, P4_COLLSEQ);
+        VdbeCoverageIf(v, ii<pList->nExpr-1 && op==OP_Eq);
+        VdbeCoverageIf(v, ii==pList->nExpr-1 && op==OP_Eq);
+        VdbeCoverageIf(v, ii<pList->nExpr-1 && op==OP_NotNull);
+        VdbeCoverageIf(v, ii==pList->nExpr-1 && op==OP_NotNull);
+        sqlite3VdbeChangeP5(v, zAff[0]);
+      }else{
+        int op = rLhs!=r2 ? OP_Ne : OP_IsNull;
+        assert( destIfNull==destIfFalse );
+        sqlite3VdbeAddOp4(v, op, rLhs, destIfFalse, r2,
+                          (void*)pColl, P4_COLLSEQ);
+        VdbeCoverageIf(v, op==OP_Ne);
+        VdbeCoverageIf(v, op==OP_IsNull);
+        sqlite3VdbeChangeP5(v, zAff[0] | SQLITE_JUMPIFNULL);
+      }
+    }
+    if( regCkNull ){
+      sqlite3VdbeAddOp2(v, OP_IsNull, regCkNull, destIfNull); VdbeCoverage(v);
+      sqlite3VdbeGoto(v, destIfFalse);
+    }
+    sqlite3VdbeResolveLabel(v, labelOk);
+    sqlite3ReleaseTempReg(pParse, regCkNull);
+    goto sqlite3ExprCodeIN_finished;
+  }
+
+  /* Step 2: Check to see if the LHS contains any NULL columns.  If the
+  ** LHS does contain NULLs then the result must be either FALSE or NULL.
+  ** We will then skip the binary search of the RHS.
+  */
+  if( destIfNull==destIfFalse ){
+    destStep2 = destIfFalse;
+  }else{
+    destStep2 = destStep6 = sqlite3VdbeMakeLabel(pParse);
+  }
+  for(i=0; i<nVector; i++){
+    Expr *p = sqlite3VectorFieldSubexpr(pExpr->pLeft, i);
+    if( pParse->nErr ) goto sqlite3ExprCodeIN_oom_error;
+    if( sqlite3ExprCanBeNull(p) ){
+      sqlite3VdbeAddOp2(v, OP_IsNull, rLhs+i, destStep2);
+      VdbeCoverage(v);
+    }
+  }
+
+  /* Step 3.  The LHS is now known to be non-NULL.  Do the binary search
+  ** of the RHS using the LHS as a probe.  If found, the result is
+  ** true.
+  */
+  if( eType==IN_INDEX_ROWID ){
+    /* In this case, the RHS is the ROWID of table b-tree and so we also
+    ** know that the RHS is non-NULL.  Hence, we combine steps 3 and 4
+    ** into a single opcode. */
+    sqlite3VdbeAddOp3(v, OP_SeekRowid, iTab, destIfFalse, rLhs);
+    VdbeCoverage(v);
+    addrTruthOp = sqlite3VdbeAddOp0(v, OP_Goto);  /* Return True */
+  }else{
+    sqlite3VdbeAddOp4(v, OP_Affinity, rLhs, nVector, 0, zAff, nVector);
+    if( destIfFalse==destIfNull ){
+      /* Combine Step 3 and Step 5 into a single opcode */
+      if( ExprHasProperty(pExpr, EP_Subrtn) ){
+        const VdbeOp *pOp = sqlite3VdbeGetOp(v, pExpr->y.sub.iAddr);
+        assert( pOp->opcode==OP_Once || pParse->nErr );
+        if( pOp->opcode==OP_Once && pOp->p3>0 ){
+          assert( OptimizationEnabled(pParse->db, SQLITE_BloomFilter) );
+          sqlite3VdbeAddOp4Int(v, OP_Filter, pOp->p3, destIfFalse,
+                               rLhs, nVector); VdbeCoverage(v);
+        }
+      }
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, iTab, destIfFalse,
+                           rLhs, nVector); VdbeCoverage(v);
+      goto sqlite3ExprCodeIN_finished;
+    }
+    /* Ordinary Step 3, for the case where FALSE and NULL are distinct */
+    addrTruthOp = sqlite3VdbeAddOp4Int(v, OP_Found, iTab, 0,
+                                      rLhs, nVector); VdbeCoverage(v);
+  }
+
+  /* Step 4.  If the RHS is known to be non-NULL and we did not find
+  ** an match on the search above, then the result must be FALSE.
+  */
+  if( rRhsHasNull && nVector==1 ){
+    sqlite3VdbeAddOp2(v, OP_NotNull, rRhsHasNull, destIfFalse);
+    VdbeCoverage(v);
+  }
+
+  /* Step 5.  If we do not care about the difference between NULL and
+  ** FALSE, then just return false.
+  */
+  if( destIfFalse==destIfNull ) sqlite3VdbeGoto(v, destIfFalse);
+
+  /* Step 6: Loop through rows of the RHS.  Compare each row to the LHS.
+  ** If any comparison is NULL, then the result is NULL.  If all
+  ** comparisons are FALSE then the final result is FALSE.
+  **
+  ** For a scalar LHS, it is sufficient to check just the first row
+  ** of the RHS.
+  */
+  if( destStep6 ) sqlite3VdbeResolveLabel(v, destStep6);
+  addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, destIfFalse);
+  VdbeCoverage(v);
+  if( nVector>1 ){
+    destNotNull = sqlite3VdbeMakeLabel(pParse);
+  }else{
+    /* For nVector==1, combine steps 6 and 7 by immediately returning
+    ** FALSE if the first comparison is not NULL */
+    destNotNull = destIfFalse;
+  }
+  for(i=0; i<nVector; i++){
+    Expr *p;
+    CollSeq *pColl;
+    int r3 = sqlite3GetTempReg(pParse);
+    p = sqlite3VectorFieldSubexpr(pLeft, i);
+    pColl = sqlite3ExprCollSeq(pParse, p);
+    sqlite3VdbeAddOp3(v, OP_Column, iTab, i, r3);
+    sqlite3VdbeAddOp4(v, OP_Ne, rLhs+i, destNotNull, r3,
+                      (void*)pColl, P4_COLLSEQ);
+    VdbeCoverage(v);
+    sqlite3ReleaseTempReg(pParse, r3);
+  }
+  sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfNull);
+  if( nVector>1 ){
+    sqlite3VdbeResolveLabel(v, destNotNull);
+    sqlite3VdbeAddOp2(v, OP_Next, iTab, addrTop+1);
+    VdbeCoverage(v);
+
+    /* Step 7:  If we reach this point, we know that the result must
+    ** be false. */
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse);
+  }
+
+  /* Jumps here in order to return true. */
+  sqlite3VdbeJumpHere(v, addrTruthOp);
+
+sqlite3ExprCodeIN_finished:
+  if( rLhs!=rLhsOrig ) sqlite3ReleaseTempReg(pParse, rLhs);
+  VdbeComment((v, "end IN expr"));
+sqlite3ExprCodeIN_oom_error:
+  sqlite3DbFree(pParse->db, aiMap);
+  sqlite3DbFree(pParse->db, zAff);
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Generate an instruction that will put the floating point
+** value described by z[0..n-1] into register iMem.
+**
+** The z[] string will probably not be zero-terminated.  But the
+** z[n] character is guaranteed to be something that does not look
+** like the continuation of the number.
+*/
+static void codeReal(Vdbe *v, const char *z, int negateFlag, int iMem){
+  if( ALWAYS(z!=0) ){
+    double value;
+    sqlite3AtoF(z, &value, sqlite3Strlen30(z), SQLITE_UTF8);
+    assert( !sqlite3IsNaN(value) ); /* The new AtoF never returns NaN */
+    if( negateFlag ) value = -value;
+    sqlite3VdbeAddOp4Dup8(v, OP_Real, 0, iMem, 0, (u8*)&value, P4_REAL);
+  }
+}
+#endif
+
+
+/*
+** Generate an instruction that will put the integer describe by
+** text z[0..n-1] into register iMem.
+**
+** Expr.u.zToken is always UTF8 and zero-terminated.
+*/
+static void codeInteger(Parse *pParse, Expr *pExpr, int negFlag, int iMem){
+  Vdbe *v = pParse->pVdbe;
+  if( pExpr->flags & EP_IntValue ){
+    int i = pExpr->u.iValue;
+    assert( i>=0 );
+    if( negFlag ) i = -i;
+    sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
+  }else{
+    int c;
+    i64 value;
+    const char *z = pExpr->u.zToken;
+    assert( z!=0 );
+    c = sqlite3DecOrHexToI64(z, &value);
+    if( (c==3 && !negFlag) || (c==2) || (negFlag && value==SMALLEST_INT64)){
+#ifdef SQLITE_OMIT_FLOATING_POINT
+      sqlite3ErrorMsg(pParse, "oversized integer: %s%#T", negFlag?"-":"",pExpr);
+#else
+#ifndef SQLITE_OMIT_HEX_INTEGER
+      if( sqlite3_strnicmp(z,"0x",2)==0 ){
+        sqlite3ErrorMsg(pParse, "hex literal too big: %s%#T",
+                        negFlag?"-":"",pExpr);
+      }else
+#endif
+      {
+        codeReal(v, z, negFlag, iMem);
+      }
+#endif
+    }else{
+      if( negFlag ){ value = c==3 ? SMALLEST_INT64 : -value; }
+      sqlite3VdbeAddOp4Dup8(v, OP_Int64, 0, iMem, 0, (u8*)&value, P4_INT64);
+    }
+  }
+}
+
+
+/* Generate code that will load into register regOut a value that is
+** appropriate for the iIdxCol-th column of index pIdx.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeLoadIndexColumn(
+  Parse *pParse,  /* The parsing context */
+  Index *pIdx,    /* The index whose column is to be loaded */
+  int iTabCur,    /* Cursor pointing to a table row */
+  int iIdxCol,    /* The column of the index to be loaded */
+  int regOut      /* Store the index column value in this register */
+){
+  i16 iTabCol = pIdx->aiColumn[iIdxCol];
+  if( iTabCol==XN_EXPR ){
+    assert( pIdx->aColExpr );
+    assert( pIdx->aColExpr->nExpr>iIdxCol );
+    pParse->iSelfTab = iTabCur + 1;
+    sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[iIdxCol].pExpr, regOut);
+    pParse->iSelfTab = 0;
+  }else{
+    sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pIdx->pTable, iTabCur,
+                                    iTabCol, regOut);
+  }
+}
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+/*
+** Generate code that will compute the value of generated column pCol
+** and store the result in register regOut
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeGeneratedColumn(
+  Parse *pParse,     /* Parsing context */
+  Table *pTab,       /* Table containing the generated column */
+  Column *pCol,      /* The generated column */
+  int regOut         /* Put the result in this register */
+){
+  int iAddr;
+  Vdbe *v = pParse->pVdbe;
+  int nErr = pParse->nErr;
+  assert( v!=0 );
+  assert( pParse->iSelfTab!=0 );
+  if( pParse->iSelfTab>0 ){
+    iAddr = sqlite3VdbeAddOp3(v, OP_IfNullRow, pParse->iSelfTab-1, 0, regOut);
+  }else{
+    iAddr = 0;
+  }
+  sqlite3ExprCodeCopy(pParse, sqlite3ColumnExpr(pTab,pCol), regOut);
+  if( pCol->affinity>=SQLITE_AFF_TEXT ){
+    sqlite3VdbeAddOp4(v, OP_Affinity, regOut, 1, 0, &pCol->affinity, 1);
+  }
+  if( iAddr ) sqlite3VdbeJumpHere(v, iAddr);
+  if( pParse->nErr>nErr ) pParse->db->errByteOffset = -1;
+}
+#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
+
+/*
+** Generate code to extract the value of the iCol-th column of a table.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeGetColumnOfTable(
+  Vdbe *v,        /* Parsing context */
+  Table *pTab,    /* The table containing the value */
+  int iTabCur,    /* The table cursor.  Or the PK cursor for WITHOUT ROWID */
+  int iCol,       /* Index of the column to extract */
+  int regOut      /* Extract the value into this register */
+){
+  Column *pCol;
+  assert( v!=0 );
+  assert( pTab!=0 );
+  assert( iCol!=XN_EXPR );
+  if( iCol<0 || iCol==pTab->iPKey ){
+    sqlite3VdbeAddOp2(v, OP_Rowid, iTabCur, regOut);
+    VdbeComment((v, "%s.rowid", pTab->zName));
+  }else{
+    int op;
+    int x;
+    if( IsVirtual(pTab) ){
+      op = OP_VColumn;
+      x = iCol;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    }else if( (pCol = &pTab->aCol[iCol])->colFlags & COLFLAG_VIRTUAL ){
+      Parse *pParse = sqlite3VdbeParser(v);
+      if( pCol->colFlags & COLFLAG_BUSY ){
+        sqlite3ErrorMsg(pParse, "generated column loop on \"%s\"",
+                        pCol->zCnName);
+      }else{
+        int savedSelfTab = pParse->iSelfTab;
+        pCol->colFlags |= COLFLAG_BUSY;
+        pParse->iSelfTab = iTabCur+1;
+        sqlite3ExprCodeGeneratedColumn(pParse, pTab, pCol, regOut);
+        pParse->iSelfTab = savedSelfTab;
+        pCol->colFlags &= ~COLFLAG_BUSY;
+      }
+      return;
+#endif
+    }else if( !HasRowid(pTab) ){
+      testcase( iCol!=sqlite3TableColumnToStorage(pTab, iCol) );
+      x = sqlite3TableColumnToIndex(sqlite3PrimaryKeyIndex(pTab), iCol);
+      op = OP_Column;
+    }else{
+      x = sqlite3TableColumnToStorage(pTab,iCol);
+      testcase( x!=iCol );
+      op = OP_Column;
+    }
+    sqlite3VdbeAddOp3(v, op, iTabCur, x, regOut);
+    sqlite3ColumnDefault(v, pTab, iCol, regOut);
+  }
+}
+
+/*
+** Generate code that will extract the iColumn-th column from
+** table pTab and store the column value in register iReg.
+**
+** There must be an open cursor to pTab in iTable when this routine
+** is called.  If iColumn<0 then code is generated that extracts the rowid.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(
+  Parse *pParse,   /* Parsing and code generating context */
+  Table *pTab,     /* Description of the table we are reading from */
+  int iColumn,     /* Index of the table column */
+  int iTable,      /* The cursor pointing to the table */
+  int iReg,        /* Store results here */
+  u8 p5            /* P5 value for OP_Column + FLAGS */
+){
+  assert( pParse->pVdbe!=0 );
+  assert( (p5 & (OPFLAG_NOCHNG|OPFLAG_TYPEOFARG|OPFLAG_LENGTHARG))==p5 );
+  assert( IsVirtual(pTab) || (p5 & OPFLAG_NOCHNG)==0 );
+  sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pTab, iTable, iColumn, iReg);
+  if( p5 ){
+    VdbeOp *pOp = sqlite3VdbeGetLastOp(pParse->pVdbe);
+    if( pOp->opcode==OP_Column ) pOp->p5 = p5;
+    if( pOp->opcode==OP_VColumn ) pOp->p5 = (p5 & OPFLAG_NOCHNG);
+  }
+  return iReg;
+}
+
+/*
+** Generate code to move content from registers iFrom...iFrom+nReg-1
+** over to iTo..iTo+nReg-1.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
+  sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);
+}
+
+/*
+** Convert a scalar expression node to a TK_REGISTER referencing
+** register iReg.  The caller must ensure that iReg already contains
+** the correct value for the expression.
+*/
+SQLITE_PRIVATE void sqlite3ExprToRegister(Expr *pExpr, int iReg){
+  Expr *p = sqlite3ExprSkipCollateAndLikely(pExpr);
+  if( NEVER(p==0) ) return;
+  if( p->op==TK_REGISTER ){
+    assert( p->iTable==iReg );
+  }else{
+    p->op2 = p->op;
+    p->op = TK_REGISTER;
+    p->iTable = iReg;
+    ExprClearProperty(p, EP_Skip);
+  }
+}
+
+/*
+** Evaluate an expression (either a vector or a scalar expression) and store
+** the result in contiguous temporary registers.  Return the index of
+** the first register used to store the result.
+**
+** If the returned result register is a temporary scalar, then also write
+** that register number into *piFreeable.  If the returned result register
+** is not a temporary or if the expression is a vector set *piFreeable
+** to 0.
+*/
+static int exprCodeVector(Parse *pParse, Expr *p, int *piFreeable){
+  int iResult;
+  int nResult = sqlite3ExprVectorSize(p);
+  if( nResult==1 ){
+    iResult = sqlite3ExprCodeTemp(pParse, p, piFreeable);
+  }else{
+    *piFreeable = 0;
+    if( p->op==TK_SELECT ){
+#if SQLITE_OMIT_SUBQUERY
+      iResult = 0;
+#else
+      iResult = sqlite3CodeSubselect(pParse, p);
+#endif
+    }else{
+      int i;
+      iResult = pParse->nMem+1;
+      pParse->nMem += nResult;
+      assert( ExprUseXList(p) );
+      for(i=0; i<nResult; i++){
+        sqlite3ExprCodeFactorable(pParse, p->x.pList->a[i].pExpr, i+iResult);
+      }
+    }
+  }
+  return iResult;
+}
+
+/*
+** If the last opcode is a OP_Copy, then set the do-not-merge flag (p5)
+** so that a subsequent copy will not be merged into this one.
+*/
+static void setDoNotMergeFlagOnCopy(Vdbe *v){
+  if( sqlite3VdbeGetLastOp(v)->opcode==OP_Copy ){
+    sqlite3VdbeChangeP5(v, 1);  /* Tag trailing OP_Copy as not mergeable */
+  }
+}
+
+/*
+** Generate code to implement special SQL functions that are implemented
+** in-line rather than by using the usual callbacks.
+*/
+static int exprCodeInlineFunction(
+  Parse *pParse,        /* Parsing context */
+  ExprList *pFarg,      /* List of function arguments */
+  int iFuncId,          /* Function ID.  One of the INTFUNC_... values */
+  int target            /* Store function result in this register */
+){
+  int nFarg;
+  Vdbe *v = pParse->pVdbe;
+  assert( v!=0 );
+  assert( pFarg!=0 );
+  nFarg = pFarg->nExpr;
+  assert( nFarg>0 );  /* All in-line functions have at least one argument */
+  switch( iFuncId ){
+    case INLINEFUNC_coalesce: {
+      /* Attempt a direct implementation of the built-in COALESCE() and
+      ** IFNULL() functions.  This avoids unnecessary evaluation of
+      ** arguments past the first non-NULL argument.
+      */
+      int endCoalesce = sqlite3VdbeMakeLabel(pParse);
+      int i;
+      assert( nFarg>=2 );
+      sqlite3ExprCode(pParse, pFarg->a[0].pExpr, target);
+      for(i=1; i<nFarg; i++){
+        sqlite3VdbeAddOp2(v, OP_NotNull, target, endCoalesce);
+        VdbeCoverage(v);
+        sqlite3ExprCode(pParse, pFarg->a[i].pExpr, target);
+      }
+      setDoNotMergeFlagOnCopy(v);
+      sqlite3VdbeResolveLabel(v, endCoalesce);
+      break;
+    }
+    case INLINEFUNC_iif: {
+      Expr caseExpr;
+      memset(&caseExpr, 0, sizeof(caseExpr));
+      caseExpr.op = TK_CASE;
+      caseExpr.x.pList = pFarg;
+      return sqlite3ExprCodeTarget(pParse, &caseExpr, target);
+    }
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+    case INLINEFUNC_sqlite_offset: {
+      Expr *pArg = pFarg->a[0].pExpr;
+      if( pArg->op==TK_COLUMN && pArg->iTable>=0 ){
+        sqlite3VdbeAddOp3(v, OP_Offset, pArg->iTable, pArg->iColumn, target);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      }
+      break;
+    }
+#endif
+    default: {
+      /* The UNLIKELY() function is a no-op.  The result is the value
+      ** of the first argument.
+      */
+      assert( nFarg==1 || nFarg==2 );
+      target = sqlite3ExprCodeTarget(pParse, pFarg->a[0].pExpr, target);
+      break;
+    }
+
+  /***********************************************************************
+  ** Test-only SQL functions that are only usable if enabled
+  ** via SQLITE_TESTCTRL_INTERNAL_FUNCTIONS
+  */
+#if !defined(SQLITE_UNTESTABLE)
+    case INLINEFUNC_expr_compare: {
+      /* Compare two expressions using sqlite3ExprCompare() */
+      assert( nFarg==2 );
+      sqlite3VdbeAddOp2(v, OP_Integer,
+         sqlite3ExprCompare(0,pFarg->a[0].pExpr, pFarg->a[1].pExpr,-1),
+         target);
+      break;
+    }
+
+    case INLINEFUNC_expr_implies_expr: {
+      /* Compare two expressions using sqlite3ExprImpliesExpr() */
+      assert( nFarg==2 );
+      sqlite3VdbeAddOp2(v, OP_Integer,
+         sqlite3ExprImpliesExpr(pParse,pFarg->a[0].pExpr, pFarg->a[1].pExpr,-1),
+         target);
+      break;
+    }
+
+    case INLINEFUNC_implies_nonnull_row: {
+      /* Result of sqlite3ExprImpliesNonNullRow() */
+      Expr *pA1;
+      assert( nFarg==2 );
+      pA1 = pFarg->a[1].pExpr;
+      if( pA1->op==TK_COLUMN ){
+        sqlite3VdbeAddOp2(v, OP_Integer,
+           sqlite3ExprImpliesNonNullRow(pFarg->a[0].pExpr,pA1->iTable,1),
+           target);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      }
+      break;
+    }
+
+    case INLINEFUNC_affinity: {
+      /* The AFFINITY() function evaluates to a string that describes
+      ** the type affinity of the argument.  This is used for testing of
+      ** the SQLite type logic.
+      */
+      const char *azAff[] = { "blob", "text", "numeric", "integer",
+                              "real", "flexnum" };
+      char aff;
+      assert( nFarg==1 );
+      aff = sqlite3ExprAffinity(pFarg->a[0].pExpr);
+      assert( aff<=SQLITE_AFF_NONE
+           || (aff>=SQLITE_AFF_BLOB && aff<=SQLITE_AFF_FLEXNUM) );
+      sqlite3VdbeLoadString(v, target,
+              (aff<=SQLITE_AFF_NONE) ? "none" : azAff[aff-SQLITE_AFF_BLOB]);
+      break;
+    }
+#endif /* !defined(SQLITE_UNTESTABLE) */
+  }
+  return target;
+}
+
+/*
+** Expression Node callback for sqlite3ExprCanReturnSubtype().
+**
+** Only a function call is able to return a subtype.  So if the node
+** is not a function call, return WRC_Prune immediately.
+**
+** A function call is able to return a subtype if it has the
+** SQLITE_RESULT_SUBTYPE property.
+**
+** Assume that every function is able to pass-through a subtype from
+** one of its argument (using sqlite3_result_value()).  Most functions
+** are not this way, but we don't have a mechanism to distinguish those
+** that are from those that are not, so assume they all work this way.
+** That means that if one of its arguments is another function and that
+** other function is able to return a subtype, then this function is
+** able to return a subtype.
+*/
+static int exprNodeCanReturnSubtype(Walker *pWalker, Expr *pExpr){
+  int n;
+  FuncDef *pDef;
+  sqlite3 *db;
+  if( pExpr->op!=TK_FUNCTION ){
+    return WRC_Prune;
+  }
+  assert( ExprUseXList(pExpr) );
+  db = pWalker->pParse->db;
+  n = ALWAYS(pExpr->x.pList) ? pExpr->x.pList->nExpr : 0;
+  pDef = sqlite3FindFunction(db, pExpr->u.zToken, n, ENC(db), 0);
+  if( NEVER(pDef==0) || (pDef->funcFlags & SQLITE_RESULT_SUBTYPE)!=0 ){
+    pWalker->eCode = 1;
+    return WRC_Prune;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Return TRUE if expression pExpr is able to return a subtype.
+**
+** A TRUE return does not guarantee that a subtype will be returned.
+** It only indicates that a subtype return is possible.  False positives
+** are acceptable as they only disable an optimization.  False negatives,
+** on the other hand, can lead to incorrect answers.
+*/
+static int sqlite3ExprCanReturnSubtype(Parse *pParse, Expr *pExpr){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.pParse = pParse;
+  w.xExprCallback = exprNodeCanReturnSubtype;
+  sqlite3WalkExpr(&w, pExpr);
+  return w.eCode;
+}
+
+
+/*
+** Check to see if pExpr is one of the indexed expressions on pParse->pIdxEpr.
+** If it is, then resolve the expression by reading from the index and
+** return the register into which the value has been read.  If pExpr is
+** not an indexed expression, then return negative.
+*/
+static SQLITE_NOINLINE int sqlite3IndexedExprLookup(
+  Parse *pParse,   /* The parsing context */
+  Expr *pExpr,     /* The expression to potentially bypass */
+  int target       /* Where to store the result of the expression */
+){
+  IndexedExpr *p;
+  Vdbe *v;
+  for(p=pParse->pIdxEpr; p; p=p->pIENext){
+    u8 exprAff;
+    int iDataCur = p->iDataCur;
+    if( iDataCur<0 ) continue;
+    if( pParse->iSelfTab ){
+      if( p->iDataCur!=pParse->iSelfTab-1 ) continue;
+      iDataCur = -1;
+    }
+    if( sqlite3ExprCompare(0, pExpr, p->pExpr, iDataCur)!=0 ) continue;
+    assert( p->aff>=SQLITE_AFF_BLOB && p->aff<=SQLITE_AFF_NUMERIC );
+    exprAff = sqlite3ExprAffinity(pExpr);
+    if( (exprAff<=SQLITE_AFF_BLOB && p->aff!=SQLITE_AFF_BLOB)
+     || (exprAff==SQLITE_AFF_TEXT && p->aff!=SQLITE_AFF_TEXT)
+     || (exprAff>=SQLITE_AFF_NUMERIC && p->aff!=SQLITE_AFF_NUMERIC)
+    ){
+      /* Affinity mismatch on a generated column */
+      continue;
+    }
+
+
+    /* Functions that might set a subtype should not be replaced by the
+    ** value taken from an expression index if they are themselves an
+    ** argument to another scalar function or aggregate.
+    ** https://sqlite.org/forum/forumpost/68d284c86b082c3e */
+    if( ExprHasProperty(pExpr, EP_SubtArg)
+     && sqlite3ExprCanReturnSubtype(pParse, pExpr)
+    ){
+      continue;
+    }
+
+    v = pParse->pVdbe;
+    assert( v!=0 );
+    if( p->bMaybeNullRow ){
+      /* If the index is on a NULL row due to an outer join, then we
+      ** cannot extract the value from the index.  The value must be
+      ** computed using the original expression. */
+      int addr = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp3(v, OP_IfNullRow, p->iIdxCur, addr+3, target);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_Column, p->iIdxCur, p->iIdxCol, target);
+      VdbeComment((v, "%s expr-column %d", p->zIdxName, p->iIdxCol));
+      sqlite3VdbeGoto(v, 0);
+      p = pParse->pIdxEpr;
+      pParse->pIdxEpr = 0;
+      sqlite3ExprCode(pParse, pExpr, target);
+      pParse->pIdxEpr = p;
+      sqlite3VdbeJumpHere(v, addr+2);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_Column, p->iIdxCur, p->iIdxCol, target);
+      VdbeComment((v, "%s expr-column %d", p->zIdxName, p->iIdxCol));
+    }
+    return target;
+  }
+  return -1;  /* Not found */
+}
+
+
+/*
+** Expresion pExpr is guaranteed to be a TK_COLUMN or equivalent. This
+** function checks the Parse.pIdxPartExpr list to see if this column
+** can be replaced with a constant value. If so, it generates code to
+** put the constant value in a register (ideally, but not necessarily,
+** register iTarget) and returns the register number.
+**
+** Or, if the TK_COLUMN cannot be replaced by a constant, zero is
+** returned.
+*/
+static int exprPartidxExprLookup(Parse *pParse, Expr *pExpr, int iTarget){
+  IndexedExpr *p;
+  for(p=pParse->pIdxPartExpr; p; p=p->pIENext){
+    if( pExpr->iColumn==p->iIdxCol && pExpr->iTable==p->iDataCur ){
+      Vdbe *v = pParse->pVdbe;
+      int addr = 0;
+      int ret;
+
+      if( p->bMaybeNullRow ){
+        addr = sqlite3VdbeAddOp1(v, OP_IfNullRow, p->iIdxCur);
+      }
+      ret = sqlite3ExprCodeTarget(pParse, p->pExpr, iTarget);
+      sqlite3VdbeAddOp4(pParse->pVdbe, OP_Affinity, ret, 1, 0,
+                        (const char*)&p->aff, 1);
+      if( addr ){
+        sqlite3VdbeJumpHere(v, addr);
+        sqlite3VdbeChangeP3(v, addr, ret);
+      }
+      return ret;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** Generate code into the current Vdbe to evaluate the given
+** expression.  Attempt to store the results in register "target".
+** Return the register where results are stored.
+**
+** With this routine, there is no guarantee that results will
+** be stored in target.  The result might be stored in some other
+** register if it is convenient to do so.  The calling function
+** must check the return code and move the results to the desired
+** register.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
+  Vdbe *v = pParse->pVdbe;  /* The VM under construction */
+  int op;                   /* The opcode being coded */
+  int inReg = target;       /* Results stored in register inReg */
+  int regFree1 = 0;         /* If non-zero free this temporary register */
+  int regFree2 = 0;         /* If non-zero free this temporary register */
+  int r1, r2;               /* Various register numbers */
+  Expr tempX;               /* Temporary expression node */
+  int p5 = 0;
+
+  assert( target>0 && target<=pParse->nMem );
+  assert( v!=0 );
+
+expr_code_doover:
+  if( pExpr==0 ){
+    op = TK_NULL;
+  }else if( pParse->pIdxEpr!=0
+   && !ExprHasProperty(pExpr, EP_Leaf)
+   && (r1 = sqlite3IndexedExprLookup(pParse, pExpr, target))>=0
+  ){
+    return r1;
+  }else{
+    assert( !ExprHasVVAProperty(pExpr,EP_Immutable) );
+    op = pExpr->op;
+  }
+  assert( op!=TK_ORDER );
+  switch( op ){
+    case TK_AGG_COLUMN: {
+      AggInfo *pAggInfo = pExpr->pAggInfo;
+      struct AggInfo_col *pCol;
+      assert( pAggInfo!=0 );
+      assert( pExpr->iAgg>=0 );
+      if( pExpr->iAgg>=pAggInfo->nColumn ){
+        /* Happens when the left table of a RIGHT JOIN is null and
+        ** is using an expression index */
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+#ifdef SQLITE_VDBE_COVERAGE
+        /* Verify that the OP_Null above is exercised by tests
+        ** tag-20230325-2 */
+        sqlite3VdbeAddOp3(v, OP_NotNull, target, 1, 20230325);
+        VdbeCoverageNeverTaken(v);
+#endif
+        break;
+      }
+      pCol = &pAggInfo->aCol[pExpr->iAgg];
+      if( !pAggInfo->directMode ){
+        return AggInfoColumnReg(pAggInfo, pExpr->iAgg);
+      }else if( pAggInfo->useSortingIdx ){
+        Table *pTab = pCol->pTab;
+        sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdxPTab,
+                              pCol->iSorterColumn, target);
+        if( pTab==0 ){
+          /* No comment added */
+        }else if( pCol->iColumn<0 ){
+          VdbeComment((v,"%s.rowid",pTab->zName));
+        }else{
+          VdbeComment((v,"%s.%s",
+              pTab->zName, pTab->aCol[pCol->iColumn].zCnName));
+          if( pTab->aCol[pCol->iColumn].affinity==SQLITE_AFF_REAL ){
+            sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
+          }
+        }
+        return target;
+      }else if( pExpr->y.pTab==0 ){
+        /* This case happens when the argument to an aggregate function
+        ** is rewritten by aggregateConvertIndexedExprRefToColumn() */
+        sqlite3VdbeAddOp3(v, OP_Column, pExpr->iTable, pExpr->iColumn, target);
+        return target;
+      }
+      /* Otherwise, fall thru into the TK_COLUMN case */
+      /* no break */ deliberate_fall_through
+    }
+    case TK_COLUMN: {
+      int iTab = pExpr->iTable;
+      int iReg;
+      if( ExprHasProperty(pExpr, EP_FixedCol) ){
+        /* This COLUMN expression is really a constant due to WHERE clause
+        ** constraints, and that constant is coded by the pExpr->pLeft
+        ** expression.  However, make sure the constant has the correct
+        ** datatype by applying the Affinity of the table column to the
+        ** constant.
+        */
+        int aff;
+        iReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft,target);
+        assert( ExprUseYTab(pExpr) );
+        assert( pExpr->y.pTab!=0 );
+        aff = sqlite3TableColumnAffinity(pExpr->y.pTab, pExpr->iColumn);
+        if( aff>SQLITE_AFF_BLOB ){
+          static const char zAff[] = "B\000C\000D\000E\000F";
+          assert( SQLITE_AFF_BLOB=='A' );
+          assert( SQLITE_AFF_TEXT=='B' );
+          sqlite3VdbeAddOp4(v, OP_Affinity, iReg, 1, 0,
+                            &zAff[(aff-'B')*2], P4_STATIC);
+        }
+        return iReg;
+      }
+      if( iTab<0 ){
+        if( pParse->iSelfTab<0 ){
+          /* Other columns in the same row for CHECK constraints or
+          ** generated columns or for inserting into partial index.
+          ** The row is unpacked into registers beginning at
+          ** 0-(pParse->iSelfTab).  The rowid (if any) is in a register
+          ** immediately prior to the first column.
+          */
+          Column *pCol;
+          Table *pTab;
+          int iSrc;
+          int iCol = pExpr->iColumn;
+          assert( ExprUseYTab(pExpr) );
+          pTab = pExpr->y.pTab;
+          assert( pTab!=0 );
+          assert( iCol>=XN_ROWID );
+          assert( iCol<pTab->nCol );
+          if( iCol<0 ){
+            return -1-pParse->iSelfTab;
+          }
+          pCol = pTab->aCol + iCol;
+          testcase( iCol!=sqlite3TableColumnToStorage(pTab,iCol) );
+          iSrc = sqlite3TableColumnToStorage(pTab, iCol) - pParse->iSelfTab;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+          if( pCol->colFlags & COLFLAG_GENERATED ){
+            if( pCol->colFlags & COLFLAG_BUSY ){
+              sqlite3ErrorMsg(pParse, "generated column loop on \"%s\"",
+                              pCol->zCnName);
+              return 0;
+            }
+            pCol->colFlags |= COLFLAG_BUSY;
+            if( pCol->colFlags & COLFLAG_NOTAVAIL ){
+              sqlite3ExprCodeGeneratedColumn(pParse, pTab, pCol, iSrc);
+            }
+            pCol->colFlags &= ~(COLFLAG_BUSY|COLFLAG_NOTAVAIL);
+            return iSrc;
+          }else
+#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
+          if( pCol->affinity==SQLITE_AFF_REAL ){
+            sqlite3VdbeAddOp2(v, OP_SCopy, iSrc, target);
+            sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
+            return target;
+          }else{
+            return iSrc;
+          }
+        }else{
+          /* Coding an expression that is part of an index where column names
+          ** in the index refer to the table to which the index belongs */
+          iTab = pParse->iSelfTab - 1;
+        }
+      }
+      else if( pParse->pIdxPartExpr
+       && 0!=(r1 = exprPartidxExprLookup(pParse, pExpr, target))
+      ){
+        return r1;
+      }
+      assert( ExprUseYTab(pExpr) );
+      assert( pExpr->y.pTab!=0 );
+      iReg = sqlite3ExprCodeGetColumn(pParse, pExpr->y.pTab,
+                               pExpr->iColumn, iTab, target,
+                               pExpr->op2);
+      return iReg;
+    }
+    case TK_INTEGER: {
+      codeInteger(pParse, pExpr, 0, target);
+      return target;
+    }
+    case TK_TRUEFALSE: {
+      sqlite3VdbeAddOp2(v, OP_Integer, sqlite3ExprTruthValue(pExpr), target);
+      return target;
+    }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    case TK_FLOAT: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      codeReal(v, pExpr->u.zToken, 0, target);
+      return target;
+    }
+#endif
+    case TK_STRING: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3VdbeLoadString(v, target, pExpr->u.zToken);
+      return target;
+    }
+    default: {
+      /* Make NULL the default case so that if a bug causes an illegal
+      ** Expr node to be passed into this function, it will be handled
+      ** sanely and not crash.  But keep the assert() to bring the problem
+      ** to the attention of the developers. */
+      assert( op==TK_NULL || op==TK_ERROR || pParse->db->mallocFailed );
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      return target;
+    }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+    case TK_BLOB: {
+      int n;
+      const char *z;
+      char *zBlob;
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
+      assert( pExpr->u.zToken[1]=='\'' );
+      z = &pExpr->u.zToken[2];
+      n = sqlite3Strlen30(z) - 1;
+      assert( z[n]=='\'' );
+      zBlob = sqlite3HexToBlob(sqlite3VdbeDb(v), z, n);
+      sqlite3VdbeAddOp4(v, OP_Blob, n/2, target, 0, zBlob, P4_DYNAMIC);
+      return target;
+    }
+#endif
+    case TK_VARIABLE: {
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      assert( pExpr->u.zToken!=0 );
+      assert( pExpr->u.zToken[0]!=0 );
+      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iColumn, target);
+      return target;
+    }
+    case TK_REGISTER: {
+      return pExpr->iTable;
+    }
+#ifndef SQLITE_OMIT_CAST
+    case TK_CAST: {
+      /* Expressions of the form:   CAST(pLeft AS token) */
+      sqlite3ExprCode(pParse, pExpr->pLeft, target);
+      assert( inReg==target );
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      sqlite3VdbeAddOp2(v, OP_Cast, target,
+                        sqlite3AffinityType(pExpr->u.zToken, 0));
+      return inReg;
+    }
+#endif /* SQLITE_OMIT_CAST */
+    case TK_IS:
+    case TK_ISNOT:
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      p5 = SQLITE_NULLEQ;
+      /* fall-through */
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      Expr *pLeft = pExpr->pLeft;
+      if( sqlite3ExprIsVector(pLeft) ){
+        codeVectorCompare(pParse, pExpr, target, op, p5);
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pLeft, ®Free1);
+        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, ®Free2);
+        sqlite3VdbeAddOp2(v, OP_Integer, 1, inReg);
+        codeCompare(pParse, pLeft, pExpr->pRight, op, r1, r2,
+            sqlite3VdbeCurrentAddr(v)+2, p5,
+            ExprHasProperty(pExpr,EP_Commuted));
+        assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+        assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+        assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+        assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+        assert(TK_EQ==OP_Eq); testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
+        assert(TK_NE==OP_Ne); testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
+        if( p5==SQLITE_NULLEQ ){
+          sqlite3VdbeAddOp2(v, OP_Integer, 0, inReg);
+        }else{
+          sqlite3VdbeAddOp3(v, OP_ZeroOrNull, r1, inReg, r2);
+        }
+        testcase( regFree1==0 );
+        testcase( regFree2==0 );
+      }
+      break;
+    }
+    case TK_AND:
+    case TK_OR:
+    case TK_PLUS:
+    case TK_STAR:
+    case TK_MINUS:
+    case TK_REM:
+    case TK_BITAND:
+    case TK_BITOR:
+    case TK_SLASH:
+    case TK_LSHIFT:
+    case TK_RSHIFT:
+    case TK_CONCAT: {
+      assert( TK_AND==OP_And );            testcase( op==TK_AND );
+      assert( TK_OR==OP_Or );              testcase( op==TK_OR );
+      assert( TK_PLUS==OP_Add );           testcase( op==TK_PLUS );
+      assert( TK_MINUS==OP_Subtract );     testcase( op==TK_MINUS );
+      assert( TK_REM==OP_Remainder );      testcase( op==TK_REM );
+      assert( TK_BITAND==OP_BitAnd );      testcase( op==TK_BITAND );
+      assert( TK_BITOR==OP_BitOr );        testcase( op==TK_BITOR );
+      assert( TK_SLASH==OP_Divide );       testcase( op==TK_SLASH );
+      assert( TK_LSHIFT==OP_ShiftLeft );   testcase( op==TK_LSHIFT );
+      assert( TK_RSHIFT==OP_ShiftRight );  testcase( op==TK_RSHIFT );
+      assert( TK_CONCAT==OP_Concat );      testcase( op==TK_CONCAT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, ®Free2);
+      sqlite3VdbeAddOp3(v, op, r2, r1, target);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_UMINUS: {
+      Expr *pLeft = pExpr->pLeft;
+      assert( pLeft );
+      if( pLeft->op==TK_INTEGER ){
+        codeInteger(pParse, pLeft, 1, target);
+        return target;
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      }else if( pLeft->op==TK_FLOAT ){
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        codeReal(v, pLeft->u.zToken, 1, target);
+        return target;
+#endif
+      }else{
+        tempX.op = TK_INTEGER;
+        tempX.flags = EP_IntValue|EP_TokenOnly;
+        tempX.u.iValue = 0;
+        ExprClearVVAProperties(&tempX);
+        r1 = sqlite3ExprCodeTemp(pParse, &tempX, ®Free1);
+        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free2);
+        sqlite3VdbeAddOp3(v, OP_Subtract, r2, r1, target);
+        testcase( regFree2==0 );
+      }
+      break;
+    }
+    case TK_BITNOT:
+    case TK_NOT: {
+      assert( TK_BITNOT==OP_BitNot );   testcase( op==TK_BITNOT );
+      assert( TK_NOT==OP_Not );         testcase( op==TK_NOT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      testcase( regFree1==0 );
+      sqlite3VdbeAddOp2(v, op, r1, inReg);
+      break;
+    }
+    case TK_TRUTH: {
+      int isTrue;    /* IS TRUE or IS NOT TRUE */
+      int bNormal;   /* IS TRUE or IS FALSE */
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      testcase( regFree1==0 );
+      isTrue = sqlite3ExprTruthValue(pExpr->pRight);
+      bNormal = pExpr->op2==TK_IS;
+      testcase( isTrue && bNormal);
+      testcase( !isTrue && bNormal);
+      sqlite3VdbeAddOp4Int(v, OP_IsTrue, r1, inReg, !isTrue, isTrue ^ bNormal);
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      int addr;
+      assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
+      assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      testcase( regFree1==0 );
+      addr = sqlite3VdbeAddOp1(v, op, r1);
+      VdbeCoverageIf(v, op==TK_ISNULL);
+      VdbeCoverageIf(v, op==TK_NOTNULL);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, target);
+      sqlite3VdbeJumpHere(v, addr);
+      break;
+    }
+    case TK_AGG_FUNCTION: {
+      AggInfo *pInfo = pExpr->pAggInfo;
+      if( pInfo==0
+       || NEVER(pExpr->iAgg<0)
+       || NEVER(pExpr->iAgg>=pInfo->nFunc)
+      ){
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        sqlite3ErrorMsg(pParse, "misuse of aggregate: %#T()", pExpr);
+      }else{
+        return AggInfoFuncReg(pInfo, pExpr->iAgg);
+      }
+      break;
+    }
+    case TK_FUNCTION: {
+      ExprList *pFarg;       /* List of function arguments */
+      int nFarg;             /* Number of function arguments */
+      FuncDef *pDef;         /* The function definition object */
+      const char *zId;       /* The function name */
+      u32 constMask = 0;     /* Mask of function arguments that are constant */
+      int i;                 /* Loop counter */
+      sqlite3 *db = pParse->db;  /* The database connection */
+      u8 enc = ENC(db);      /* The text encoding used by this database */
+      CollSeq *pColl = 0;    /* A collating sequence */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( ExprHasProperty(pExpr, EP_WinFunc) ){
+        return pExpr->y.pWin->regResult;
+      }
+#endif
+
+      if( ConstFactorOk(pParse)
+       && sqlite3ExprIsConstantNotJoin(pParse,pExpr)
+      ){
+        /* SQL functions can be expensive. So try to avoid running them
+        ** multiple times if we know they always give the same result */
+        return sqlite3ExprCodeRunJustOnce(pParse, pExpr, -1);
+      }
+      assert( !ExprHasProperty(pExpr, EP_TokenOnly) );
+      assert( ExprUseXList(pExpr) );
+      pFarg = pExpr->x.pList;
+      nFarg = pFarg ? pFarg->nExpr : 0;
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      zId = pExpr->u.zToken;
+      pDef = sqlite3FindFunction(db, zId, nFarg, enc, 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+      if( pDef==0 && pParse->explain ){
+        pDef = sqlite3FindFunction(db, "unknown", nFarg, enc, 0);
+      }
+#endif
+      if( pDef==0 || pDef->xFinalize!=0 ){
+        sqlite3ErrorMsg(pParse, "unknown function: %#T()", pExpr);
+        break;
+      }
+      if( (pDef->funcFlags & SQLITE_FUNC_INLINE)!=0 && ALWAYS(pFarg!=0) ){
+        assert( (pDef->funcFlags & SQLITE_FUNC_UNSAFE)==0 );
+        assert( (pDef->funcFlags & SQLITE_FUNC_DIRECT)==0 );
+        return exprCodeInlineFunction(pParse, pFarg,
+             SQLITE_PTR_TO_INT(pDef->pUserData), target);
+      }else if( pDef->funcFlags & (SQLITE_FUNC_DIRECT|SQLITE_FUNC_UNSAFE) ){
+        sqlite3ExprFunctionUsable(pParse, pExpr, pDef);
+      }
+
+      for(i=0; i<nFarg; i++){
+        if( i<32 && sqlite3ExprIsConstant(pParse, pFarg->a[i].pExpr) ){
+          testcase( i==31 );
+          constMask |= MASKBIT32(i);
+        }
+        if( (pDef->funcFlags & SQLITE_FUNC_NEEDCOLL)!=0 && !pColl ){
+          pColl = sqlite3ExprCollSeq(pParse, pFarg->a[i].pExpr);
+        }
+      }
+      if( pFarg ){
+        if( constMask ){
+          r1 = pParse->nMem+1;
+          pParse->nMem += nFarg;
+        }else{
+          r1 = sqlite3GetTempRange(pParse, nFarg);
+        }
+
+        /* For length() and typeof() and octet_length() functions,
+        ** set the P5 parameter to the OP_Column opcode to OPFLAG_LENGTHARG
+        ** or OPFLAG_TYPEOFARG or OPFLAG_BYTELENARG respectively, to avoid
+        ** unnecessary data loading.
+        */
+        if( (pDef->funcFlags & (SQLITE_FUNC_LENGTH|SQLITE_FUNC_TYPEOF))!=0 ){
+          u8 exprOp;
+          assert( nFarg==1 );
+          assert( pFarg->a[0].pExpr!=0 );
+          exprOp = pFarg->a[0].pExpr->op;
+          if( exprOp==TK_COLUMN || exprOp==TK_AGG_COLUMN ){
+            assert( SQLITE_FUNC_LENGTH==OPFLAG_LENGTHARG );
+            assert( SQLITE_FUNC_TYPEOF==OPFLAG_TYPEOFARG );
+            assert( SQLITE_FUNC_BYTELEN==OPFLAG_BYTELENARG );
+            assert( (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG)==OPFLAG_BYTELENARG );
+            testcase( (pDef->funcFlags & OPFLAG_BYTELENARG)==OPFLAG_LENGTHARG );
+            testcase( (pDef->funcFlags & OPFLAG_BYTELENARG)==OPFLAG_TYPEOFARG );
+            testcase( (pDef->funcFlags & OPFLAG_BYTELENARG)==OPFLAG_BYTELENARG);
+            pFarg->a[0].pExpr->op2 = pDef->funcFlags & OPFLAG_BYTELENARG;
+          }
+        }
+
+        sqlite3ExprCodeExprList(pParse, pFarg, r1, 0, SQLITE_ECEL_FACTOR);
+      }else{
+        r1 = 0;
+      }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      /* Possibly overload the function if the first argument is
+      ** a virtual table column.
+      **
+      ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
+      ** second argument, not the first, as the argument to test to
+      ** see if it is a column in a virtual table.  This is done because
+      ** the left operand of infix functions (the operand we want to
+      ** control overloading) ends up as the second argument to the
+      ** function.  The expression "A glob B" is equivalent to
+      ** "glob(B,A).  We want to use the A in "A glob B" to test
+      ** for function overloading.  But we use the B term in "glob(B,A)".
+      */
+      if( nFarg>=2 && ExprHasProperty(pExpr, EP_InfixFunc) ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[1].pExpr);
+      }else if( nFarg>0 ){
+        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[0].pExpr);
+      }
+#endif
+      if( pDef->funcFlags & SQLITE_FUNC_NEEDCOLL ){
+        if( !pColl ) pColl = db->pDfltColl;
+        sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
+      }
+      sqlite3VdbeAddFunctionCall(pParse, constMask, r1, target, nFarg,
+                                 pDef, pExpr->op2);
+      if( nFarg ){
+        if( constMask==0 ){
+          sqlite3ReleaseTempRange(pParse, r1, nFarg);
+        }else{
+          sqlite3VdbeReleaseRegisters(pParse, r1, nFarg, constMask, 1);
+        }
+      }
+      return target;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_EXISTS:
+    case TK_SELECT: {
+      int nCol;
+      testcase( op==TK_EXISTS );
+      testcase( op==TK_SELECT );
+      if( pParse->db->mallocFailed ){
+        return 0;
+      }else if( op==TK_SELECT
+             && ALWAYS( ExprUseXSelect(pExpr) )
+             && (nCol = pExpr->x.pSelect->pEList->nExpr)!=1
+      ){
+        sqlite3SubselectError(pParse, nCol, 1);
+      }else{
+        return sqlite3CodeSubselect(pParse, pExpr);
+      }
+      break;
+    }
+    case TK_SELECT_COLUMN: {
+      int n;
+      Expr *pLeft = pExpr->pLeft;
+      if( pLeft->iTable==0 || pParse->withinRJSubrtn > pLeft->op2 ){
+        pLeft->iTable = sqlite3CodeSubselect(pParse, pLeft);
+        pLeft->op2 = pParse->withinRJSubrtn;
+      }
+      assert( pLeft->op==TK_SELECT || pLeft->op==TK_ERROR );
+      n = sqlite3ExprVectorSize(pLeft);
+      if( pExpr->iTable!=n ){
+        sqlite3ErrorMsg(pParse, "%d columns assigned %d values",
+                                pExpr->iTable, n);
+      }
+      return pLeft->iTable + pExpr->iColumn;
+    }
+    case TK_IN: {
+      int destIfFalse = sqlite3VdbeMakeLabel(pParse);
+      int destIfNull = sqlite3VdbeMakeLabel(pParse);
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      sqlite3VdbeAddOp2(v, OP_AddImm, target, 0);
+      sqlite3VdbeResolveLabel(v, destIfNull);
+      return target;
+    }
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+
+    /*
+    **    x BETWEEN y AND z
+    **
+    ** This is equivalent to
+    **
+    **    x>=y AND x<=z
+    **
+    ** X is stored in pExpr->pLeft.
+    ** Y is stored in pExpr->pList->a[0].pExpr.
+    ** Z is stored in pExpr->pList->a[1].pExpr.
+    */
+    case TK_BETWEEN: {
+      exprCodeBetween(pParse, pExpr, target, 0, 0);
+      return target;
+    }
+    case TK_COLLATE: {
+      if( !ExprHasProperty(pExpr, EP_Collate) ){
+        /* A TK_COLLATE Expr node without the EP_Collate tag is a so-called
+        ** "SOFT-COLLATE" that is added to constraints that are pushed down
+        ** from outer queries into sub-queries by the WHERE-clause push-down
+        ** optimization. Clear subtypes as subtypes may not cross a subquery
+        ** boundary.
+        */
+        assert( pExpr->pLeft );
+        sqlite3ExprCode(pParse, pExpr->pLeft, target);
+        sqlite3VdbeAddOp1(v, OP_ClrSubtype, target);
+        return target;
+      }else{
+        pExpr = pExpr->pLeft;
+        goto expr_code_doover; /* 2018-04-28: Prevent deep recursion. */
+      }
+    }
+    case TK_SPAN:
+    case TK_UPLUS: {
+      pExpr = pExpr->pLeft;
+      goto expr_code_doover; /* 2018-04-28: Prevent deep recursion. OSSFuzz. */
+    }
+
+    case TK_TRIGGER: {
+      /* If the opcode is TK_TRIGGER, then the expression is a reference
+      ** to a column in the new.* or old.* pseudo-tables available to
+      ** trigger programs. In this case Expr.iTable is set to 1 for the
+      ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
+      ** is set to the column of the pseudo-table to read, or to -1 to
+      ** read the rowid field.
+      **
+      ** The expression is implemented using an OP_Param opcode. The p1
+      ** parameter is set to 0 for an old.rowid reference, or to (i+1)
+      ** to reference another column of the old.* pseudo-table, where
+      ** i is the index of the column. For a new.rowid reference, p1 is
+      ** set to (n+1), where n is the number of columns in each pseudo-table.
+      ** For a reference to any other column in the new.* pseudo-table, p1
+      ** is set to (n+2+i), where n and i are as defined previously. For
+      ** example, if the table on which triggers are being fired is
+      ** declared as:
+      **
+      **   CREATE TABLE t1(a, b);
+      **
+      ** Then p1 is interpreted as follows:
+      **
+      **   p1==0   ->    old.rowid     p1==3   ->    new.rowid
+      **   p1==1   ->    old.a         p1==4   ->    new.a
+      **   p1==2   ->    old.b         p1==5   ->    new.b
+      */
+      Table *pTab;
+      int iCol;
+      int p1;
+
+      assert( ExprUseYTab(pExpr) );
+      pTab = pExpr->y.pTab;
+      iCol = pExpr->iColumn;
+      p1 = pExpr->iTable * (pTab->nCol+1) + 1
+                     + sqlite3TableColumnToStorage(pTab, iCol);
+
+      assert( pExpr->iTable==0 || pExpr->iTable==1 );
+      assert( iCol>=-1 && iCol<pTab->nCol );
+      assert( pTab->iPKey<0 || iCol!=pTab->iPKey );
+      assert( p1>=0 && p1<(pTab->nCol*2+2) );
+
+      sqlite3VdbeAddOp2(v, OP_Param, p1, target);
+      VdbeComment((v, "r[%d]=%s.%s", target,
+        (pExpr->iTable ? "new" : "old"),
+        (pExpr->iColumn<0 ? "rowid" : pExpr->y.pTab->aCol[iCol].zCnName)
+      ));
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      /* If the column has REAL affinity, it may currently be stored as an
+      ** integer. Use OP_RealAffinity to make sure it is really real.
+      **
+      ** EVIDENCE-OF: R-60985-57662 SQLite will convert the value back to
+      ** floating point when extracting it from the record.  */
+      if( iCol>=0 && pTab->aCol[iCol].affinity==SQLITE_AFF_REAL ){
+        sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
+      }
+#endif
+      break;
+    }
+
+    case TK_VECTOR: {
+      sqlite3ErrorMsg(pParse, "row value misused");
+      break;
+    }
+
+    /* TK_IF_NULL_ROW Expr nodes are inserted ahead of expressions
+    ** that derive from the right-hand table of a LEFT JOIN.  The
+    ** Expr.iTable value is the table number for the right-hand table.
+    ** The expression is only evaluated if that table is not currently
+    ** on a LEFT JOIN NULL row.
+    */
+    case TK_IF_NULL_ROW: {
+      int addrINR;
+      u8 okConstFactor = pParse->okConstFactor;
+      AggInfo *pAggInfo = pExpr->pAggInfo;
+      if( pAggInfo ){
+        assert( pExpr->iAgg>=0 && pExpr->iAgg<pAggInfo->nColumn );
+        if( !pAggInfo->directMode ){
+          inReg = AggInfoColumnReg(pAggInfo, pExpr->iAgg);
+          break;
+        }
+        if( pExpr->pAggInfo->useSortingIdx ){
+          sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdxPTab,
+                            pAggInfo->aCol[pExpr->iAgg].iSorterColumn,
+                            target);
+          inReg = target;
+          break;
+        }
+      }
+      addrINR = sqlite3VdbeAddOp3(v, OP_IfNullRow, pExpr->iTable, 0, target);
+      /* The OP_IfNullRow opcode above can overwrite the result register with
+      ** NULL.  So we have to ensure that the result register is not a value
+      ** that is suppose to be a constant.  Two defenses are needed:
+      **   (1)  Temporarily disable factoring of constant expressions
+      **   (2)  Make sure the computed value really is stored in register
+      **        "target" and not someplace else.
+      */
+      pParse->okConstFactor = 0;   /* note (1) above */
+      sqlite3ExprCode(pParse, pExpr->pLeft, target);
+      assert( target==inReg );
+      pParse->okConstFactor = okConstFactor;
+      sqlite3VdbeJumpHere(v, addrINR);
+      break;
+    }
+
+    /*
+    ** Form A:
+    **   CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
+    **
+    ** Form B:
+    **   CASE WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
+    **
+    ** Form A is can be transformed into the equivalent form B as follows:
+    **   CASE WHEN x=e1 THEN r1 WHEN x=e2 THEN r2 ...
+    **        WHEN x=eN THEN rN ELSE y END
+    **
+    ** X (if it exists) is in pExpr->pLeft.
+    ** Y is in the last element of pExpr->x.pList if pExpr->x.pList->nExpr is
+    ** odd.  The Y is also optional.  If the number of elements in x.pList
+    ** is even, then Y is omitted and the "otherwise" result is NULL.
+    ** Ei is in pExpr->pList->a[i*2] and Ri is pExpr->pList->a[i*2+1].
+    **
+    ** The result of the expression is the Ri for the first matching Ei,
+    ** or if there is no matching Ei, the ELSE term Y, or if there is
+    ** no ELSE term, NULL.
+    */
+    case TK_CASE: {
+      int endLabel;                     /* GOTO label for end of CASE stmt */
+      int nextCase;                     /* GOTO label for next WHEN clause */
+      int nExpr;                        /* 2x number of WHEN terms */
+      int i;                            /* Loop counter */
+      ExprList *pEList;                 /* List of WHEN terms */
+      struct ExprList_item *aListelem;  /* Array of WHEN terms */
+      Expr opCompare;                   /* The X==Ei expression */
+      Expr *pX;                         /* The X expression */
+      Expr *pTest = 0;                  /* X==Ei (form A) or just Ei (form B) */
+      Expr *pDel = 0;
+      sqlite3 *db = pParse->db;
+
+      assert( ExprUseXList(pExpr) && pExpr->x.pList!=0 );
+      assert(pExpr->x.pList->nExpr > 0);
+      pEList = pExpr->x.pList;
+      aListelem = pEList->a;
+      nExpr = pEList->nExpr;
+      endLabel = sqlite3VdbeMakeLabel(pParse);
+      if( (pX = pExpr->pLeft)!=0 ){
+        pDel = sqlite3ExprDup(db, pX, 0);
+        if( db->mallocFailed ){
+          sqlite3ExprDelete(db, pDel);
+          break;
+        }
+        testcase( pX->op==TK_COLUMN );
+        sqlite3ExprToRegister(pDel, exprCodeVector(pParse, pDel, ®Free1));
+        testcase( regFree1==0 );
+        memset(&opCompare, 0, sizeof(opCompare));
+        opCompare.op = TK_EQ;
+        opCompare.pLeft = pDel;
+        pTest = &opCompare;
+        /* Ticket b351d95f9cd5ef17e9d9dbae18f5ca8611190001:
+        ** The value in regFree1 might get SCopy-ed into the file result.
+        ** So make sure that the regFree1 register is not reused for other
+        ** purposes and possibly overwritten.  */
+        regFree1 = 0;
+      }
+      for(i=0; i<nExpr-1; i=i+2){
+        if( pX ){
+          assert( pTest!=0 );
+          opCompare.pRight = aListelem[i].pExpr;
+        }else{
+          pTest = aListelem[i].pExpr;
+        }
+        nextCase = sqlite3VdbeMakeLabel(pParse);
+        testcase( pTest->op==TK_COLUMN );
+        sqlite3ExprIfFalse(pParse, pTest, nextCase, SQLITE_JUMPIFNULL);
+        testcase( aListelem[i+1].pExpr->op==TK_COLUMN );
+        sqlite3ExprCode(pParse, aListelem[i+1].pExpr, target);
+        sqlite3VdbeGoto(v, endLabel);
+        sqlite3VdbeResolveLabel(v, nextCase);
+      }
+      if( (nExpr&1)!=0 ){
+        sqlite3ExprCode(pParse, pEList->a[nExpr-1].pExpr, target);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      }
+      sqlite3ExprDelete(db, pDel);
+      setDoNotMergeFlagOnCopy(v);
+      sqlite3VdbeResolveLabel(v, endLabel);
+      break;
+    }
+#ifndef SQLITE_OMIT_TRIGGER
+    case TK_RAISE: {
+      assert( pExpr->affExpr==OE_Rollback
+           || pExpr->affExpr==OE_Abort
+           || pExpr->affExpr==OE_Fail
+           || pExpr->affExpr==OE_Ignore
+      );
+      if( !pParse->pTriggerTab && !pParse->nested ){
+        sqlite3ErrorMsg(pParse,
+                       "RAISE() may only be used within a trigger-program");
+        return 0;
+      }
+      if( pExpr->affExpr==OE_Abort ){
+        sqlite3MayAbort(pParse);
+      }
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      if( pExpr->affExpr==OE_Ignore ){
+        sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, OE_Ignore);
+        VdbeCoverage(v);
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+        sqlite3VdbeAddOp3(v, OP_Halt,
+             pParse->pTriggerTab ? SQLITE_CONSTRAINT_TRIGGER : SQLITE_ERROR,
+             pExpr->affExpr, r1);
+      }
+      break;
+    }
+#endif
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+  return inReg;
+}
+
+/*
+** Generate code that will evaluate expression pExpr just one time
+** per prepared statement execution.
+**
+** If the expression uses functions (that might throw an exception) then
+** guard them with an OP_Once opcode to ensure that the code is only executed
+** once. If no functions are involved, then factor the code out and put it at
+** the end of the prepared statement in the initialization section.
+**
+** If regDest>0 then the result is always stored in that register and the
+** result is not reusable.  If regDest<0 then this routine is free to
+** store the value wherever it wants.  The register where the expression
+** is stored is returned.  When regDest<0, two identical expressions might
+** code to the same register, if they do not contain function calls and hence
+** are factored out into the initialization section at the end of the
+** prepared statement.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeRunJustOnce(
+  Parse *pParse,    /* Parsing context */
+  Expr *pExpr,      /* The expression to code when the VDBE initializes */
+  int regDest       /* Store the value in this register */
+){
+  ExprList *p;
+  assert( ConstFactorOk(pParse) );
+  assert( regDest!=0 );
+  p = pParse->pConstExpr;
+  if( regDest<0 && p ){
+    struct ExprList_item *pItem;
+    int i;
+    for(pItem=p->a, i=p->nExpr; i>0; pItem++, i--){
+      if( pItem->fg.reusable
+       && sqlite3ExprCompare(0,pItem->pExpr,pExpr,-1)==0
+      ){
+        return pItem->u.iConstExprReg;
+      }
+    }
+  }
+  pExpr = sqlite3ExprDup(pParse->db, pExpr, 0);
+  if( pExpr!=0 && ExprHasProperty(pExpr, EP_HasFunc) ){
+    Vdbe *v = pParse->pVdbe;
+    int addr;
+    assert( v );
+    addr = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+    pParse->okConstFactor = 0;
+    if( !pParse->db->mallocFailed ){
+      if( regDest<0 ) regDest = ++pParse->nMem;
+      sqlite3ExprCode(pParse, pExpr, regDest);
+    }
+    pParse->okConstFactor = 1;
+    sqlite3ExprDelete(pParse->db, pExpr);
+    sqlite3VdbeJumpHere(v, addr);
+  }else{
+    p = sqlite3ExprListAppend(pParse, p, pExpr);
+    if( p ){
+       struct ExprList_item *pItem = &p->a[p->nExpr-1];
+       pItem->fg.reusable = regDest<0;
+       if( regDest<0 ) regDest = ++pParse->nMem;
+       pItem->u.iConstExprReg = regDest;
+    }
+    pParse->pConstExpr = p;
+  }
+  return regDest;
+}
+
+/*
+** Generate code to evaluate an expression and store the results
+** into a register.  Return the register number where the results
+** are stored.
+**
+** If the register is a temporary register that can be deallocated,
+** then write its number into *pReg.  If the result register is not
+** a temporary, then set *pReg to zero.
+**
+** If pExpr is a constant, then this routine might generate this
+** code to fill the register in the initialization section of the
+** VDBE program, in order to factor it out of the evaluation loop.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeTemp(Parse *pParse, Expr *pExpr, int *pReg){
+  int r2;
+  pExpr = sqlite3ExprSkipCollateAndLikely(pExpr);
+  if( ConstFactorOk(pParse)
+   && ALWAYS(pExpr!=0)
+   && pExpr->op!=TK_REGISTER
+   && sqlite3ExprIsConstantNotJoin(pParse, pExpr)
+  ){
+    *pReg  = 0;
+    r2 = sqlite3ExprCodeRunJustOnce(pParse, pExpr, -1);
+  }else{
+    int r1 = sqlite3GetTempReg(pParse);
+    r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
+    if( r2==r1 ){
+      *pReg = r1;
+    }else{
+      sqlite3ReleaseTempReg(pParse, r1);
+      *pReg = 0;
+    }
+  }
+  return r2;
+}
+
+/*
+** Generate code that will evaluate expression pExpr and store the
+** results in register target.  The results are guaranteed to appear
+** in register target.
+*/
+SQLITE_PRIVATE void sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
+  int inReg;
+
+  assert( pExpr==0 || !ExprHasVVAProperty(pExpr,EP_Immutable) );
+  assert( target>0 && target<=pParse->nMem );
+  assert( pParse->pVdbe!=0 || pParse->db->mallocFailed );
+  if( pParse->pVdbe==0 ) return;
+  inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
+  if( inReg!=target ){
+    u8 op;
+    Expr *pX = sqlite3ExprSkipCollateAndLikely(pExpr);
+    testcase( pX!=pExpr );
+    if( ALWAYS(pX)
+     && (ExprHasProperty(pX,EP_Subquery) || pX->op==TK_REGISTER)
+    ){
+      op = OP_Copy;
+    }else{
+      op = OP_SCopy;
+    }
+    sqlite3VdbeAddOp2(pParse->pVdbe, op, inReg, target);
+  }
+}
+
+/*
+** Make a transient copy of expression pExpr and then code it using
+** sqlite3ExprCode().  This routine works just like sqlite3ExprCode()
+** except that the input expression is guaranteed to be unchanged.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeCopy(Parse *pParse, Expr *pExpr, int target){
+  sqlite3 *db = pParse->db;
+  pExpr = sqlite3ExprDup(db, pExpr, 0);
+  if( !db->mallocFailed ) sqlite3ExprCode(pParse, pExpr, target);
+  sqlite3ExprDelete(db, pExpr);
+}
+
+/*
+** Generate code that will evaluate expression pExpr and store the
+** results in register target.  The results are guaranteed to appear
+** in register target.  If the expression is constant, then this routine
+** might choose to code the expression at initialization time.
+*/
+SQLITE_PRIVATE void sqlite3ExprCodeFactorable(Parse *pParse, Expr *pExpr, int target){
+  if( pParse->okConstFactor && sqlite3ExprIsConstantNotJoin(pParse,pExpr) ){
+    sqlite3ExprCodeRunJustOnce(pParse, pExpr, target);
+  }else{
+    sqlite3ExprCodeCopy(pParse, pExpr, target);
+  }
+}
+
+/*
+** Generate code that pushes the value of every element of the given
+** expression list into a sequence of registers beginning at target.
+**
+** Return the number of elements evaluated.  The number returned will
+** usually be pList->nExpr but might be reduced if SQLITE_ECEL_OMITREF
+** is defined.
+**
+** The SQLITE_ECEL_DUP flag prevents the arguments from being
+** filled using OP_SCopy.  OP_Copy must be used instead.
+**
+** The SQLITE_ECEL_FACTOR argument allows constant arguments to be
+** factored out into initialization code.
+**
+** The SQLITE_ECEL_REF flag means that expressions in the list with
+** ExprList.a[].u.x.iOrderByCol>0 have already been evaluated and stored
+** in registers at srcReg, and so the value can be copied from there.
+** If SQLITE_ECEL_OMITREF is also set, then the values with u.x.iOrderByCol>0
+** are simply omitted rather than being copied from srcReg.
+*/
+SQLITE_PRIVATE int sqlite3ExprCodeExprList(
+  Parse *pParse,     /* Parsing context */
+  ExprList *pList,   /* The expression list to be coded */
+  int target,        /* Where to write results */
+  int srcReg,        /* Source registers if SQLITE_ECEL_REF */
+  u8 flags           /* SQLITE_ECEL_* flags */
+){
+  struct ExprList_item *pItem;
+  int i, j, n;
+  u8 copyOp = (flags & SQLITE_ECEL_DUP) ? OP_Copy : OP_SCopy;
+  Vdbe *v = pParse->pVdbe;
+  assert( pList!=0 );
+  assert( target>0 );
+  assert( pParse->pVdbe!=0 );  /* Never gets this far otherwise */
+  n = pList->nExpr;
+  if( !ConstFactorOk(pParse) ) flags &= ~SQLITE_ECEL_FACTOR;
+  for(pItem=pList->a, i=0; i<n; i++, pItem++){
+    Expr *pExpr = pItem->pExpr;
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( pItem->fg.bSorterRef ){
+      i--;
+      n--;
+    }else
+#endif
+    if( (flags & SQLITE_ECEL_REF)!=0 && (j = pItem->u.x.iOrderByCol)>0 ){
+      if( flags & SQLITE_ECEL_OMITREF ){
+        i--;
+        n--;
+      }else{
+        sqlite3VdbeAddOp2(v, copyOp, j+srcReg-1, target+i);
+      }
+    }else if( (flags & SQLITE_ECEL_FACTOR)!=0
+           && sqlite3ExprIsConstantNotJoin(pParse,pExpr)
+    ){
+      sqlite3ExprCodeRunJustOnce(pParse, pExpr, target+i);
+    }else{
+      int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
+      if( inReg!=target+i ){
+        VdbeOp *pOp;
+        if( copyOp==OP_Copy
+         && (pOp=sqlite3VdbeGetLastOp(v))->opcode==OP_Copy
+         && pOp->p1+pOp->p3+1==inReg
+         && pOp->p2+pOp->p3+1==target+i
+         && pOp->p5==0  /* The do-not-merge flag must be clear */
+        ){
+          pOp->p3++;
+        }else{
+          sqlite3VdbeAddOp2(v, copyOp, inReg, target+i);
+        }
+      }
+    }
+  }
+  return n;
+}
+
+/*
+** Generate code for a BETWEEN operator.
+**
+**    x BETWEEN y AND z
+**
+** The above is equivalent to
+**
+**    x>=y AND x<=z
+**
+** Code it as such, taking care to do the common subexpression
+** elimination of x.
+**
+** The xJumpIf parameter determines details:
+**
+**    NULL:                   Store the boolean result in reg[dest]
+**    sqlite3ExprIfTrue:      Jump to dest if true
+**    sqlite3ExprIfFalse:     Jump to dest if false
+**
+** The jumpIfNull parameter is ignored if xJumpIf is NULL.
+*/
+static void exprCodeBetween(
+  Parse *pParse,    /* Parsing and code generating context */
+  Expr *pExpr,      /* The BETWEEN expression */
+  int dest,         /* Jump destination or storage location */
+  void (*xJump)(Parse*,Expr*,int,int), /* Action to take */
+  int jumpIfNull    /* Take the jump if the BETWEEN is NULL */
+){
+  Expr exprAnd;     /* The AND operator in  x>=y AND x<=z  */
+  Expr compLeft;    /* The  x>=y  term */
+  Expr compRight;   /* The  x<=z  term */
+  int regFree1 = 0; /* Temporary use register */
+  Expr *pDel = 0;
+  sqlite3 *db = pParse->db;
+
+  memset(&compLeft, 0, sizeof(Expr));
+  memset(&compRight, 0, sizeof(Expr));
+  memset(&exprAnd, 0, sizeof(Expr));
+
+  assert( ExprUseXList(pExpr) );
+  pDel = sqlite3ExprDup(db, pExpr->pLeft, 0);
+  if( db->mallocFailed==0 ){
+    exprAnd.op = TK_AND;
+    exprAnd.pLeft = &compLeft;
+    exprAnd.pRight = &compRight;
+    compLeft.op = TK_GE;
+    compLeft.pLeft = pDel;
+    compLeft.pRight = pExpr->x.pList->a[0].pExpr;
+    compRight.op = TK_LE;
+    compRight.pLeft = pDel;
+    compRight.pRight = pExpr->x.pList->a[1].pExpr;
+    sqlite3ExprToRegister(pDel, exprCodeVector(pParse, pDel, ®Free1));
+    if( xJump ){
+      xJump(pParse, &exprAnd, dest, jumpIfNull);
+    }else{
+      /* Mark the expression is being from the ON or USING clause of a join
+      ** so that the sqlite3ExprCodeTarget() routine will not attempt to move
+      ** it into the Parse.pConstExpr list.  We should use a new bit for this,
+      ** for clarity, but we are out of bits in the Expr.flags field so we
+      ** have to reuse the EP_OuterON bit.  Bummer. */
+      pDel->flags |= EP_OuterON;
+      sqlite3ExprCodeTarget(pParse, &exprAnd, dest);
+    }
+    sqlite3ReleaseTempReg(pParse, regFree1);
+  }
+  sqlite3ExprDelete(db, pDel);
+
+  /* Ensure adequate test coverage */
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull==0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull==0 && regFree1!=0 );
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull!=0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfTrue  && jumpIfNull!=0 && regFree1!=0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull==0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull==0 && regFree1!=0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull!=0 && regFree1==0 );
+  testcase( xJump==sqlite3ExprIfFalse && jumpIfNull!=0 && regFree1!=0 );
+  testcase( xJump==0 );
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is true but execution
+** continues straight thru if the expression is false.
+**
+** If the expression evaluates to NULL (neither true nor false), then
+** take the jump if the jumpIfNull flag is SQLITE_JUMPIFNULL.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align.  Assert()s in the code
+** below verify that the numbers are aligned correctly.
+*/
+SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  int regFree1 = 0;
+  int regFree2 = 0;
+  int r1, r2;
+
+  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
+  if( NEVER(v==0) )     return;  /* Existence of VDBE checked by caller */
+  if( NEVER(pExpr==0) ) return;  /* No way this can happen */
+  assert( !ExprHasVVAProperty(pExpr, EP_Immutable) );
+  op = pExpr->op;
+  switch( op ){
+    case TK_AND:
+    case TK_OR: {
+      Expr *pAlt = sqlite3ExprSimplifiedAndOr(pExpr);
+      if( pAlt!=pExpr ){
+        sqlite3ExprIfTrue(pParse, pAlt, dest, jumpIfNull);
+      }else if( op==TK_AND ){
+        int d2 = sqlite3VdbeMakeLabel(pParse);
+        testcase( jumpIfNull==0 );
+        sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,
+                           jumpIfNull^SQLITE_JUMPIFNULL);
+        sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+        sqlite3VdbeResolveLabel(v, d2);
+      }else{
+        testcase( jumpIfNull==0 );
+        sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+        sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+      }
+      break;
+    }
+    case TK_NOT: {
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_TRUTH: {
+      int isNot;      /* IS NOT TRUE or IS NOT FALSE */
+      int isTrue;     /* IS TRUE or IS NOT TRUE */
+      testcase( jumpIfNull==0 );
+      isNot = pExpr->op2==TK_ISNOT;
+      isTrue = sqlite3ExprTruthValue(pExpr->pRight);
+      testcase( isTrue && isNot );
+      testcase( !isTrue && isNot );
+      if( isTrue ^ isNot ){
+        sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest,
+                          isNot ? SQLITE_JUMPIFNULL : 0);
+      }else{
+        sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest,
+                           isNot ? SQLITE_JUMPIFNULL : 0);
+      }
+      break;
+    }
+    case TK_IS:
+    case TK_ISNOT:
+      testcase( op==TK_IS );
+      testcase( op==TK_ISNOT );
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      jumpIfNull = SQLITE_NULLEQ;
+      /* no break */ deliberate_fall_through
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
+      testcase( jumpIfNull==0 );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, ®Free2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, jumpIfNull, ExprHasProperty(pExpr,EP_Commuted));
+      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+      assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+      assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull==SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull!=SQLITE_NULLEQ);
+      assert(TK_NE==OP_Ne); testcase(op==OP_Ne);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull==SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull!=SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
+      assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      assert( regFree1==0 || regFree1==r1 );
+      if( regFree1 ) sqlite3VdbeTypeofColumn(v, r1);
+      sqlite3VdbeAddOp2(v, op, r1, dest);
+      VdbeCoverageIf(v, op==TK_ISNULL);
+      VdbeCoverageIf(v, op==TK_NOTNULL);
+      break;
+    }
+    case TK_BETWEEN: {
+      testcase( jumpIfNull==0 );
+      exprCodeBetween(pParse, pExpr, dest, sqlite3ExprIfTrue, jumpIfNull);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_IN: {
+      int destIfFalse = sqlite3VdbeMakeLabel(pParse);
+      int destIfNull = jumpIfNull ? dest : destIfFalse;
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeGoto(v, dest);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      break;
+    }
+#endif
+    default: {
+    default_expr:
+      if( ExprAlwaysTrue(pExpr) ){
+        sqlite3VdbeGoto(v, dest);
+      }else if( ExprAlwaysFalse(pExpr) ){
+        /* No-op */
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pExpr, ®Free1);
+        sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0);
+        VdbeCoverage(v);
+        testcase( regFree1==0 );
+        testcase( jumpIfNull==0 );
+      }
+      break;
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+}
+
+/*
+** Generate code for a boolean expression such that a jump is made
+** to the label "dest" if the expression is false but execution
+** continues straight thru if the expression is true.
+**
+** If the expression evaluates to NULL (neither true nor false) then
+** jump if jumpIfNull is SQLITE_JUMPIFNULL or fall through if jumpIfNull
+** is 0.
+*/
+SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
+  Vdbe *v = pParse->pVdbe;
+  int op = 0;
+  int regFree1 = 0;
+  int regFree2 = 0;
+  int r1, r2;
+
+  assert( jumpIfNull==SQLITE_JUMPIFNULL || jumpIfNull==0 );
+  if( NEVER(v==0) ) return; /* Existence of VDBE checked by caller */
+  if( pExpr==0 )    return;
+  assert( !ExprHasVVAProperty(pExpr,EP_Immutable) );
+
+  /* The value of pExpr->op and op are related as follows:
+  **
+  **       pExpr->op            op
+  **       ---------          ----------
+  **       TK_ISNULL          OP_NotNull
+  **       TK_NOTNULL         OP_IsNull
+  **       TK_NE              OP_Eq
+  **       TK_EQ              OP_Ne
+  **       TK_GT              OP_Le
+  **       TK_LE              OP_Gt
+  **       TK_GE              OP_Lt
+  **       TK_LT              OP_Ge
+  **
+  ** For other values of pExpr->op, op is undefined and unused.
+  ** The value of TK_ and OP_ constants are arranged such that we
+  ** can compute the mapping above using the following expression.
+  ** Assert()s verify that the computation is correct.
+  */
+  op = ((pExpr->op+(TK_ISNULL&1))^1)-(TK_ISNULL&1);
+
+  /* Verify correct alignment of TK_ and OP_ constants
+  */
+  assert( pExpr->op!=TK_ISNULL || op==OP_NotNull );
+  assert( pExpr->op!=TK_NOTNULL || op==OP_IsNull );
+  assert( pExpr->op!=TK_NE || op==OP_Eq );
+  assert( pExpr->op!=TK_EQ || op==OP_Ne );
+  assert( pExpr->op!=TK_LT || op==OP_Ge );
+  assert( pExpr->op!=TK_LE || op==OP_Gt );
+  assert( pExpr->op!=TK_GT || op==OP_Le );
+  assert( pExpr->op!=TK_GE || op==OP_Lt );
+
+  switch( pExpr->op ){
+    case TK_AND:
+    case TK_OR: {
+      Expr *pAlt = sqlite3ExprSimplifiedAndOr(pExpr);
+      if( pAlt!=pExpr ){
+        sqlite3ExprIfFalse(pParse, pAlt, dest, jumpIfNull);
+      }else if( pExpr->op==TK_AND ){
+        testcase( jumpIfNull==0 );
+        sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
+        sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+      }else{
+        int d2 = sqlite3VdbeMakeLabel(pParse);
+        testcase( jumpIfNull==0 );
+        sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2,
+                          jumpIfNull^SQLITE_JUMPIFNULL);
+        sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
+        sqlite3VdbeResolveLabel(v, d2);
+      }
+      break;
+    }
+    case TK_NOT: {
+      testcase( jumpIfNull==0 );
+      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
+      break;
+    }
+    case TK_TRUTH: {
+      int isNot;   /* IS NOT TRUE or IS NOT FALSE */
+      int isTrue;  /* IS TRUE or IS NOT TRUE */
+      testcase( jumpIfNull==0 );
+      isNot = pExpr->op2==TK_ISNOT;
+      isTrue = sqlite3ExprTruthValue(pExpr->pRight);
+      testcase( isTrue && isNot );
+      testcase( !isTrue && isNot );
+      if( isTrue ^ isNot ){
+        /* IS TRUE and IS NOT FALSE */
+        sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest,
+                           isNot ? 0 : SQLITE_JUMPIFNULL);
+
+      }else{
+        /* IS FALSE and IS NOT TRUE */
+        sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest,
+                          isNot ? 0 : SQLITE_JUMPIFNULL);
+      }
+      break;
+    }
+    case TK_IS:
+    case TK_ISNOT:
+      testcase( pExpr->op==TK_IS );
+      testcase( pExpr->op==TK_ISNOT );
+      op = (pExpr->op==TK_IS) ? TK_NE : TK_EQ;
+      jumpIfNull = SQLITE_NULLEQ;
+      /* no break */ deliberate_fall_through
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_NE:
+    case TK_EQ: {
+      if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
+      testcase( jumpIfNull==0 );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, ®Free2);
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, jumpIfNull,ExprHasProperty(pExpr,EP_Commuted));
+      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
+      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
+      assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
+      assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
+      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull!=SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull==SQLITE_NULLEQ);
+      assert(TK_NE==OP_Ne); testcase(op==OP_Ne);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull!=SQLITE_NULLEQ);
+      VdbeCoverageIf(v, op==OP_Ne && jumpIfNull==SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
+    case TK_ISNULL:
+    case TK_NOTNULL: {
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, ®Free1);
+      assert( regFree1==0 || regFree1==r1 );
+      if( regFree1 ) sqlite3VdbeTypeofColumn(v, r1);
+      sqlite3VdbeAddOp2(v, op, r1, dest);
+      testcase( op==TK_ISNULL );   VdbeCoverageIf(v, op==TK_ISNULL);
+      testcase( op==TK_NOTNULL );  VdbeCoverageIf(v, op==TK_NOTNULL);
+      break;
+    }
+    case TK_BETWEEN: {
+      testcase( jumpIfNull==0 );
+      exprCodeBetween(pParse, pExpr, dest, sqlite3ExprIfFalse, jumpIfNull);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_IN: {
+      if( jumpIfNull ){
+        sqlite3ExprCodeIN(pParse, pExpr, dest, dest);
+      }else{
+        int destIfNull = sqlite3VdbeMakeLabel(pParse);
+        sqlite3ExprCodeIN(pParse, pExpr, dest, destIfNull);
+        sqlite3VdbeResolveLabel(v, destIfNull);
+      }
+      break;
+    }
+#endif
+    default: {
+    default_expr:
+      if( ExprAlwaysFalse(pExpr) ){
+        sqlite3VdbeGoto(v, dest);
+      }else if( ExprAlwaysTrue(pExpr) ){
+        /* no-op */
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pExpr, ®Free1);
+        sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0);
+        VdbeCoverage(v);
+        testcase( regFree1==0 );
+        testcase( jumpIfNull==0 );
+      }
+      break;
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+  sqlite3ReleaseTempReg(pParse, regFree2);
+}
+
+/*
+** Like sqlite3ExprIfFalse() except that a copy is made of pExpr before
+** code generation, and that copy is deleted after code generation. This
+** ensures that the original pExpr is unchanged.
+*/
+SQLITE_PRIVATE void sqlite3ExprIfFalseDup(Parse *pParse, Expr *pExpr, int dest,int jumpIfNull){
+  sqlite3 *db = pParse->db;
+  Expr *pCopy = sqlite3ExprDup(db, pExpr, 0);
+  if( db->mallocFailed==0 ){
+    sqlite3ExprIfFalse(pParse, pCopy, dest, jumpIfNull);
+  }
+  sqlite3ExprDelete(db, pCopy);
+}
+
+/*
+** Expression pVar is guaranteed to be an SQL variable. pExpr may be any
+** type of expression.
+**
+** If pExpr is a simple SQL value - an integer, real, string, blob
+** or NULL value - then the VDBE currently being prepared is configured
+** to re-prepare each time a new value is bound to variable pVar.
+**
+** Additionally, if pExpr is a simple SQL value and the value is the
+** same as that currently bound to variable pVar, non-zero is returned.
+** Otherwise, if the values are not the same or if pExpr is not a simple
+** SQL value, zero is returned.
+**
+** If the SQLITE_EnableQPSG flag is set on the database connection, then
+** this routine always returns false.
+*/
+static SQLITE_NOINLINE int exprCompareVariable(
+  const Parse *pParse,
+  const Expr *pVar,
+  const Expr *pExpr
+){
+  int res = 2;
+  int iVar;
+  sqlite3_value *pL, *pR = 0;
+
+  if( pExpr->op==TK_VARIABLE && pVar->iColumn==pExpr->iColumn ){
+    return 0;
+  }
+  if( (pParse->db->flags & SQLITE_EnableQPSG)!=0 ) return 2;
+  sqlite3ValueFromExpr(pParse->db, pExpr, SQLITE_UTF8, SQLITE_AFF_BLOB, &pR);
+  if( pR ){
+    iVar = pVar->iColumn;
+    sqlite3VdbeSetVarmask(pParse->pVdbe, iVar);
+    pL = sqlite3VdbeGetBoundValue(pParse->pReprepare, iVar, SQLITE_AFF_BLOB);
+    if( pL ){
+      if( sqlite3_value_type(pL)==SQLITE_TEXT ){
+        sqlite3_value_text(pL); /* Make sure the encoding is UTF-8 */
+      }
+      res = sqlite3MemCompare(pL, pR, 0) ? 2 : 0;
+    }
+    sqlite3ValueFree(pR);
+    sqlite3ValueFree(pL);
+  }
+  return res;
+}
+
+/*
+** Do a deep comparison of two expression trees.  Return 0 if the two
+** expressions are completely identical.  Return 1 if they differ only
+** by a COLLATE operator at the top level.  Return 2 if there are differences
+** other than the top-level COLLATE operator.
+**
+** If any subelement of pB has Expr.iTable==(-1) then it is allowed
+** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
+**
+** The pA side might be using TK_REGISTER.  If that is the case and pB is
+** not using TK_REGISTER but is otherwise equivalent, then still return 0.
+**
+** Sometimes this routine will return 2 even if the two expressions
+** really are equivalent.  If we cannot prove that the expressions are
+** identical, we return 2 just to be safe.  So if this routine
+** returns 2, then you do not really know for certain if the two
+** expressions are the same.  But if you get a 0 or 1 return, then you
+** can be sure the expressions are the same.  In the places where
+** this routine is used, it does not hurt to get an extra 2 - that
+** just might result in some slightly slower code.  But returning
+** an incorrect 0 or 1 could lead to a malfunction.
+**
+** If pParse is not NULL and SQLITE_EnableQPSG is off then TK_VARIABLE
+** terms in pA with bindings in pParse->pReprepare can be matched against
+** literals in pB.  The pParse->pVdbe->expmask bitmask is updated for
+** each variable referenced.
+*/
+SQLITE_PRIVATE int sqlite3ExprCompare(
+  const Parse *pParse,
+  const Expr *pA,
+  const Expr *pB,
+  int iTab
+){
+  u32 combinedFlags;
+  if( pA==0 || pB==0 ){
+    return pB==pA ? 0 : 2;
+  }
+  if( pParse && pA->op==TK_VARIABLE ){
+    return exprCompareVariable(pParse, pA, pB);
+  }
+  combinedFlags = pA->flags | pB->flags;
+  if( combinedFlags & EP_IntValue ){
+    if( (pA->flags&pB->flags&EP_IntValue)!=0 && pA->u.iValue==pB->u.iValue ){
+      return 0;
+    }
+    return 2;
+  }
+  if( pA->op!=pB->op || pA->op==TK_RAISE ){
+    if( pA->op==TK_COLLATE && sqlite3ExprCompare(pParse, pA->pLeft,pB,iTab)<2 ){
+      return 1;
+    }
+    if( pB->op==TK_COLLATE && sqlite3ExprCompare(pParse, pA,pB->pLeft,iTab)<2 ){
+      return 1;
+    }
+    if( pA->op==TK_AGG_COLUMN && pB->op==TK_COLUMN
+     && pB->iTable<0 && pA->iTable==iTab
+    ){
+      /* fall through */
+    }else{
+      return 2;
+    }
+  }
+  assert( !ExprHasProperty(pA, EP_IntValue) );
+  assert( !ExprHasProperty(pB, EP_IntValue) );
+  if( pA->u.zToken ){
+    if( pA->op==TK_FUNCTION || pA->op==TK_AGG_FUNCTION ){
+      if( sqlite3StrICmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      assert( pA->op==pB->op );
+      if( ExprHasProperty(pA,EP_WinFunc)!=ExprHasProperty(pB,EP_WinFunc) ){
+        return 2;
+      }
+      if( ExprHasProperty(pA,EP_WinFunc) ){
+        if( sqlite3WindowCompare(pParse, pA->y.pWin, pB->y.pWin, 1)!=0 ){
+          return 2;
+        }
+      }
+#endif
+    }else if( pA->op==TK_NULL ){
+      return 0;
+    }else if( pA->op==TK_COLLATE ){
+      if( sqlite3_stricmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
+    }else
+    if( pB->u.zToken!=0
+     && pA->op!=TK_COLUMN
+     && pA->op!=TK_AGG_COLUMN
+     && strcmp(pA->u.zToken,pB->u.zToken)!=0
+    ){
+      return 2;
+    }
+  }
+  if( (pA->flags & (EP_Distinct|EP_Commuted))
+     != (pB->flags & (EP_Distinct|EP_Commuted)) ) return 2;
+  if( ALWAYS((combinedFlags & EP_TokenOnly)==0) ){
+    if( combinedFlags & EP_xIsSelect ) return 2;
+    if( (combinedFlags & EP_FixedCol)==0
+     && sqlite3ExprCompare(pParse, pA->pLeft, pB->pLeft, iTab) ) return 2;
+    if( sqlite3ExprCompare(pParse, pA->pRight, pB->pRight, iTab) ) return 2;
+    if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList, iTab) ) return 2;
+    if( pA->op!=TK_STRING
+     && pA->op!=TK_TRUEFALSE
+     && ALWAYS((combinedFlags & EP_Reduced)==0)
+    ){
+      if( pA->iColumn!=pB->iColumn ) return 2;
+      if( pA->op2!=pB->op2 && pA->op==TK_TRUTH ) return 2;
+      if( pA->op!=TK_IN && pA->iTable!=pB->iTable && pA->iTable!=iTab ){
+        return 2;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Compare two ExprList objects.  Return 0 if they are identical, 1
+** if they are certainly different, or 2 if it is not possible to
+** determine if they are identical or not.
+**
+** If any subelement of pB has Expr.iTable==(-1) then it is allowed
+** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
+**
+** This routine might return non-zero for equivalent ExprLists.  The
+** only consequence will be disabled optimizations.  But this routine
+** must never return 0 if the two ExprList objects are different, or
+** a malfunction will result.
+**
+** Two NULL pointers are considered to be the same.  But a NULL pointer
+** always differs from a non-NULL pointer.
+*/
+SQLITE_PRIVATE int sqlite3ExprListCompare(const ExprList *pA, const ExprList *pB, int iTab){
+  int i;
+  if( pA==0 && pB==0 ) return 0;
+  if( pA==0 || pB==0 ) return 1;
+  if( pA->nExpr!=pB->nExpr ) return 1;
+  for(i=0; i<pA->nExpr; i++){
+    int res;
+    Expr *pExprA = pA->a[i].pExpr;
+    Expr *pExprB = pB->a[i].pExpr;
+    if( pA->a[i].fg.sortFlags!=pB->a[i].fg.sortFlags ) return 1;
+    if( (res = sqlite3ExprCompare(0, pExprA, pExprB, iTab)) ) return res;
+  }
+  return 0;
+}
+
+/*
+** Like sqlite3ExprCompare() except COLLATE operators at the top-level
+** are ignored.
+*/
+SQLITE_PRIVATE int sqlite3ExprCompareSkip(Expr *pA,Expr *pB, int iTab){
+  return sqlite3ExprCompare(0,
+             sqlite3ExprSkipCollate(pA),
+             sqlite3ExprSkipCollate(pB),
+             iTab);
+}
+
+/*
+** Return non-zero if Expr p can only be true if pNN is not NULL.
+**
+** Or if seenNot is true, return non-zero if Expr p can only be
+** non-NULL if pNN is not NULL
+*/
+static int exprImpliesNotNull(
+  const Parse *pParse,/* Parsing context */
+  const Expr *p,      /* The expression to be checked */
+  const Expr *pNN,    /* The expression that is NOT NULL */
+  int iTab,           /* Table being evaluated */
+  int seenNot         /* Return true only if p can be any non-NULL value */
+){
+  assert( p );
+  assert( pNN );
+  if( sqlite3ExprCompare(pParse, p, pNN, iTab)==0 ){
+    return pNN->op!=TK_NULL;
+  }
+  switch( p->op ){
+    case TK_IN: {
+      if( seenNot && ExprHasProperty(p, EP_xIsSelect) ) return 0;
+      assert( ExprUseXSelect(p) || (p->x.pList!=0 && p->x.pList->nExpr>0) );
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, 1);
+    }
+    case TK_BETWEEN: {
+      ExprList *pList;
+      assert( ExprUseXList(p) );
+      pList = p->x.pList;
+      assert( pList!=0 );
+      assert( pList->nExpr==2 );
+      if( seenNot ) return 0;
+      if( exprImpliesNotNull(pParse, pList->a[0].pExpr, pNN, iTab, 1)
+       || exprImpliesNotNull(pParse, pList->a[1].pExpr, pNN, iTab, 1)
+      ){
+        return 1;
+      }
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, 1);
+    }
+    case TK_EQ:
+    case TK_NE:
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE:
+    case TK_PLUS:
+    case TK_MINUS:
+    case TK_BITOR:
+    case TK_LSHIFT:
+    case TK_RSHIFT:
+    case TK_CONCAT:
+      seenNot = 1;
+      /* no break */ deliberate_fall_through
+    case TK_STAR:
+    case TK_REM:
+    case TK_BITAND:
+    case TK_SLASH: {
+      if( exprImpliesNotNull(pParse, p->pRight, pNN, iTab, seenNot) ) return 1;
+      /* no break */ deliberate_fall_through
+    }
+    case TK_SPAN:
+    case TK_COLLATE:
+    case TK_UPLUS:
+    case TK_UMINUS: {
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, seenNot);
+    }
+    case TK_TRUTH: {
+      if( seenNot ) return 0;
+      if( p->op2!=TK_IS ) return 0;
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, 1);
+    }
+    case TK_BITNOT:
+    case TK_NOT: {
+      return exprImpliesNotNull(pParse, p->pLeft, pNN, iTab, 1);
+    }
+  }
+  return 0;
+}
+
+/*
+** Return true if the boolean value of the expression is always either
+** FALSE or NULL.
+*/
+static int sqlite3ExprIsNotTrue(Expr *pExpr){
+  int v;
+  if( pExpr->op==TK_NULL ) return 1;
+  if( pExpr->op==TK_TRUEFALSE && sqlite3ExprTruthValue(pExpr)==0 ) return 1;
+  v = 1;
+  if( sqlite3ExprIsInteger(pExpr, &v, 0) && v==0 ) return 1;
+  return 0;
+}
+
+/*
+** Return true if the expression is one of the following:
+**
+**    CASE WHEN x THEN y END
+**    CASE WHEN x THEN y ELSE NULL END
+**    CASE WHEN x THEN y ELSE false END
+**    iif(x,y)
+**    iif(x,y,NULL)
+**    iif(x,y,false)
+*/
+static int sqlite3ExprIsIIF(sqlite3 *db, const Expr *pExpr){
+  ExprList *pList;
+  if( pExpr->op==TK_FUNCTION ){
+    const char *z = pExpr->u.zToken;
+    FuncDef *pDef;
+    if( (z[0]!='i' && z[0]!='I') ) return 0;
+    if( pExpr->x.pList==0 ) return 0;
+    pDef = sqlite3FindFunction(db, z, pExpr->x.pList->nExpr, ENC(db), 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+    if( pDef==0 ) return 0;
+#else
+    if( NEVER(pDef==0) ) return 0;
+#endif
+    if( (pDef->funcFlags & SQLITE_FUNC_INLINE)==0 ) return 0;
+    if( SQLITE_PTR_TO_INT(pDef->pUserData)!=INLINEFUNC_iif ) return 0;
+  }else if( pExpr->op==TK_CASE ){
+    if( pExpr->pLeft!=0 ) return 0;
+  }else{
+    return 0;
+  }
+  pList = pExpr->x.pList;
+  assert( pList!=0 );
+  if( pList->nExpr==2 ) return 1;
+  if( pList->nExpr==3 && sqlite3ExprIsNotTrue(pList->a[2].pExpr) ) return 1;
+  return 0;
+}
+
+/*
+** Return true if we can prove the pE2 will always be true if pE1 is
+** true.  Return false if we cannot complete the proof or if pE2 might
+** be false.  Examples:
+**
+**     pE1: x==5        pE2: x==5             Result: true
+**     pE1: x>0         pE2: x==5             Result: false
+**     pE1: x=21        pE2: x=21 OR y=43     Result: true
+**     pE1: x!=123      pE2: x IS NOT NULL    Result: true
+**     pE1: x!=?1       pE2: x IS NOT NULL    Result: true
+**     pE1: x IS NULL   pE2: x IS NOT NULL    Result: false
+**     pE1: x IS ?2     pE2: x IS NOT NULL    Result: false
+**     pE1: iif(x,y)    pE2: x                Result: true
+**     PE1: iif(x,y,0)  pE2: x                Result: true
+**
+** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has
+** Expr.iTable<0 then assume a table number given by iTab.
+**
+** If pParse is not NULL, then the values of bound variables in pE1 are
+** compared against literal values in pE2 and pParse->pVdbe->expmask is
+** modified to record which bound variables are referenced.  If pParse
+** is NULL, then false will be returned if pE1 contains any bound variables.
+**
+** When in doubt, return false.  Returning true might give a performance
+** improvement.  Returning false might cause a performance reduction, but
+** it will always give the correct answer and is hence always safe.
+*/
+SQLITE_PRIVATE int sqlite3ExprImpliesExpr(
+  const Parse *pParse,
+  const Expr *pE1,
+  const Expr *pE2,
+  int iTab
+){
+  if( sqlite3ExprCompare(pParse, pE1, pE2, iTab)==0 ){
+    return 1;
+  }
+  if( pE2->op==TK_OR
+   && (sqlite3ExprImpliesExpr(pParse, pE1, pE2->pLeft, iTab)
+             || sqlite3ExprImpliesExpr(pParse, pE1, pE2->pRight, iTab) )
+  ){
+    return 1;
+  }
+  if( pE2->op==TK_NOTNULL
+   && exprImpliesNotNull(pParse, pE1, pE2->pLeft, iTab, 0)
+  ){
+    return 1;
+  }
+  if( sqlite3ExprIsIIF(pParse->db, pE1) ){
+    return sqlite3ExprImpliesExpr(pParse,pE1->x.pList->a[0].pExpr,pE2,iTab);
+  }
+  return 0;
+}
+
+/* This is a helper function to impliesNotNullRow().  In this routine,
+** set pWalker->eCode to one only if *both* of the input expressions
+** separately have the implies-not-null-row property.
+*/
+static void bothImplyNotNullRow(Walker *pWalker, Expr *pE1, Expr *pE2){
+  if( pWalker->eCode==0 ){
+    sqlite3WalkExpr(pWalker, pE1);
+    if( pWalker->eCode ){
+      pWalker->eCode = 0;
+      sqlite3WalkExpr(pWalker, pE2);
+    }
+  }
+}
+
+/*
+** This is the Expr node callback for sqlite3ExprImpliesNonNullRow().
+** If the expression node requires that the table at pWalker->iCur
+** have one or more non-NULL column, then set pWalker->eCode to 1 and abort.
+**
+** pWalker->mWFlags is non-zero if this inquiry is being undertaking on
+** behalf of a RIGHT JOIN (or FULL JOIN).  That makes a difference when
+** evaluating terms in the ON clause of an inner join.
+**
+** This routine controls an optimization.  False positives (setting
+** pWalker->eCode to 1 when it should not be) are deadly, but false-negatives
+** (never setting pWalker->eCode) is a harmless missed optimization.
+*/
+static int impliesNotNullRow(Walker *pWalker, Expr *pExpr){
+  testcase( pExpr->op==TK_AGG_COLUMN );
+  testcase( pExpr->op==TK_AGG_FUNCTION );
+  if( ExprHasProperty(pExpr, EP_OuterON) ) return WRC_Prune;
+  if( ExprHasProperty(pExpr, EP_InnerON) && pWalker->mWFlags ){
+    /* If iCur is used in an inner-join ON clause to the left of a
+    ** RIGHT JOIN, that does *not* mean that the table must be non-null.
+    ** But it is difficult to check for that condition precisely.
+    ** To keep things simple, any use of iCur from any inner-join is
+    ** ignored while attempting to simplify a RIGHT JOIN. */
+    return WRC_Prune;
+  }
+  switch( pExpr->op ){
+    case TK_ISNOT:
+    case TK_ISNULL:
+    case TK_NOTNULL:
+    case TK_IS:
+    case TK_VECTOR:
+    case TK_FUNCTION:
+    case TK_TRUTH:
+    case TK_CASE:
+      testcase( pExpr->op==TK_ISNOT );
+      testcase( pExpr->op==TK_ISNULL );
+      testcase( pExpr->op==TK_NOTNULL );
+      testcase( pExpr->op==TK_IS );
+      testcase( pExpr->op==TK_VECTOR );
+      testcase( pExpr->op==TK_FUNCTION );
+      testcase( pExpr->op==TK_TRUTH );
+      testcase( pExpr->op==TK_CASE );
+      return WRC_Prune;
+
+    case TK_COLUMN:
+      if( pWalker->u.iCur==pExpr->iTable ){
+        pWalker->eCode = 1;
+        return WRC_Abort;
+      }
+      return WRC_Prune;
+
+    case TK_OR:
+    case TK_AND:
+      /* Both sides of an AND or OR must separately imply non-null-row.
+      ** Consider these cases:
+      **    1.  NOT (x AND y)
+      **    2.  x OR y
+      ** If only one of x or y is non-null-row, then the overall expression
+      ** can be true if the other arm is false (case 1) or true (case 2).
+      */
+      testcase( pExpr->op==TK_OR );
+      testcase( pExpr->op==TK_AND );
+      bothImplyNotNullRow(pWalker, pExpr->pLeft, pExpr->pRight);
+      return WRC_Prune;
+
+    case TK_IN:
+      /* Beware of "x NOT IN ()" and "x NOT IN (SELECT 1 WHERE false)",
+      ** both of which can be true.  But apart from these cases, if
+      ** the left-hand side of the IN is NULL then the IN itself will be
+      ** NULL. */
+      if( ExprUseXList(pExpr) && ALWAYS(pExpr->x.pList->nExpr>0) ){
+        sqlite3WalkExpr(pWalker, pExpr->pLeft);
+      }
+      return WRC_Prune;
+
+    case TK_BETWEEN:
+      /* In "x NOT BETWEEN y AND z" either x must be non-null-row or else
+      ** both y and z must be non-null row */
+      assert( ExprUseXList(pExpr) );
+      assert( pExpr->x.pList->nExpr==2 );
+      sqlite3WalkExpr(pWalker, pExpr->pLeft);
+      bothImplyNotNullRow(pWalker, pExpr->x.pList->a[0].pExpr,
+                                   pExpr->x.pList->a[1].pExpr);
+      return WRC_Prune;
+
+    /* Virtual tables are allowed to use constraints like x=NULL.  So
+    ** a term of the form x=y does not prove that y is not null if x
+    ** is the column of a virtual table */
+    case TK_EQ:
+    case TK_NE:
+    case TK_LT:
+    case TK_LE:
+    case TK_GT:
+    case TK_GE: {
+      Expr *pLeft = pExpr->pLeft;
+      Expr *pRight = pExpr->pRight;
+      testcase( pExpr->op==TK_EQ );
+      testcase( pExpr->op==TK_NE );
+      testcase( pExpr->op==TK_LT );
+      testcase( pExpr->op==TK_LE );
+      testcase( pExpr->op==TK_GT );
+      testcase( pExpr->op==TK_GE );
+      /* The y.pTab=0 assignment in wherecode.c always happens after the
+      ** impliesNotNullRow() test */
+      assert( pLeft->op!=TK_COLUMN || ExprUseYTab(pLeft) );
+      assert( pRight->op!=TK_COLUMN || ExprUseYTab(pRight) );
+      if( (pLeft->op==TK_COLUMN
+           && ALWAYS(pLeft->y.pTab!=0)
+           && IsVirtual(pLeft->y.pTab))
+       || (pRight->op==TK_COLUMN
+           && ALWAYS(pRight->y.pTab!=0)
+           && IsVirtual(pRight->y.pTab))
+      ){
+        return WRC_Prune;
+      }
+      /* no break */ deliberate_fall_through
+    }
+    default:
+      return WRC_Continue;
+  }
+}
+
+/*
+** Return true (non-zero) if expression p can only be true if at least
+** one column of table iTab is non-null.  In other words, return true
+** if expression p will always be NULL or false if every column of iTab
+** is NULL.
+**
+** False negatives are acceptable.  In other words, it is ok to return
+** zero even if expression p will never be true of every column of iTab
+** is NULL.  A false negative is merely a missed optimization opportunity.
+**
+** False positives are not allowed, however.  A false positive may result
+** in an incorrect answer.
+**
+** Terms of p that are marked with EP_OuterON (and hence that come from
+** the ON or USING clauses of OUTER JOINS) are excluded from the analysis.
+**
+** This routine is used to check if a LEFT JOIN can be converted into
+** an ordinary JOIN.  The p argument is the WHERE clause.  If the WHERE
+** clause requires that some column of the right table of the LEFT JOIN
+** be non-NULL, then the LEFT JOIN can be safely converted into an
+** ordinary join.
+*/
+SQLITE_PRIVATE int sqlite3ExprImpliesNonNullRow(Expr *p, int iTab, int isRJ){
+  Walker w;
+  p = sqlite3ExprSkipCollateAndLikely(p);
+  if( p==0 ) return 0;
+  if( p->op==TK_NOTNULL ){
+    p = p->pLeft;
+  }else{
+    while( p->op==TK_AND ){
+      if( sqlite3ExprImpliesNonNullRow(p->pLeft, iTab, isRJ) ) return 1;
+      p = p->pRight;
+    }
+  }
+  w.xExprCallback = impliesNotNullRow;
+  w.xSelectCallback = 0;
+  w.xSelectCallback2 = 0;
+  w.eCode = 0;
+  w.mWFlags = isRJ!=0;
+  w.u.iCur = iTab;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+/*
+** An instance of the following structure is used by the tree walker
+** to determine if an expression can be evaluated by reference to the
+** index only, without having to do a search for the corresponding
+** table entry.  The IdxCover.pIdx field is the index.  IdxCover.iCur
+** is the cursor for the table.
+*/
+struct IdxCover {
+  Index *pIdx;     /* The index to be tested for coverage */
+  int iCur;        /* Cursor number for the table corresponding to the index */
+};
+
+/*
+** Check to see if there are references to columns in table
+** pWalker->u.pIdxCover->iCur can be satisfied using the index
+** pWalker->u.pIdxCover->pIdx.
+*/
+static int exprIdxCover(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_COLUMN
+   && pExpr->iTable==pWalker->u.pIdxCover->iCur
+   && sqlite3TableColumnToIndex(pWalker->u.pIdxCover->pIdx, pExpr->iColumn)<0
+  ){
+    pWalker->eCode = 1;
+    return WRC_Abort;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Determine if an index pIdx on table with cursor iCur contains will
+** the expression pExpr.  Return true if the index does cover the
+** expression and false if the pExpr expression references table columns
+** that are not found in the index pIdx.
+**
+** An index covering an expression means that the expression can be
+** evaluated using only the index and without having to lookup the
+** corresponding table entry.
+*/
+SQLITE_PRIVATE int sqlite3ExprCoveredByIndex(
+  Expr *pExpr,        /* The index to be tested */
+  int iCur,           /* The cursor number for the corresponding table */
+  Index *pIdx         /* The index that might be used for coverage */
+){
+  Walker w;
+  struct IdxCover xcov;
+  memset(&w, 0, sizeof(w));
+  xcov.iCur = iCur;
+  xcov.pIdx = pIdx;
+  w.xExprCallback = exprIdxCover;
+  w.u.pIdxCover = &xcov;
+  sqlite3WalkExpr(&w, pExpr);
+  return !w.eCode;
+}
+
+
+/* Structure used to pass information throughout the Walker in order to
+** implement sqlite3ReferencesSrcList().
+*/
+struct RefSrcList {
+  sqlite3 *db;         /* Database connection used for sqlite3DbRealloc() */
+  SrcList *pRef;       /* Looking for references to these tables */
+  i64 nExclude;        /* Number of tables to exclude from the search */
+  int *aiExclude;      /* Cursor IDs for tables to exclude from the search */
+};
+
+/*
+** Walker SELECT callbacks for sqlite3ReferencesSrcList().
+**
+** When entering a new subquery on the pExpr argument, add all FROM clause
+** entries for that subquery to the exclude list.
+**
+** When leaving the subquery, remove those entries from the exclude list.
+*/
+static int selectRefEnter(Walker *pWalker, Select *pSelect){
+  struct RefSrcList *p = pWalker->u.pRefSrcList;
+  SrcList *pSrc = pSelect->pSrc;
+  i64 i, j;
+  int *piNew;
+  if( pSrc->nSrc==0 ) return WRC_Continue;
+  j = p->nExclude;
+  p->nExclude += pSrc->nSrc;
+  piNew = sqlite3DbRealloc(p->db, p->aiExclude, p->nExclude*sizeof(int));
+  if( piNew==0 ){
+    p->nExclude = 0;
+    return WRC_Abort;
+  }else{
+    p->aiExclude = piNew;
+  }
+  for(i=0; i<pSrc->nSrc; i++, j++){
+     p->aiExclude[j] = pSrc->a[i].iCursor;
+  }
+  return WRC_Continue;
+}
+static void selectRefLeave(Walker *pWalker, Select *pSelect){
+  struct RefSrcList *p = pWalker->u.pRefSrcList;
+  SrcList *pSrc = pSelect->pSrc;
+  if( p->nExclude ){
+    assert( p->nExclude>=pSrc->nSrc );
+    p->nExclude -= pSrc->nSrc;
+  }
+}
+
+/* This is the Walker EXPR callback for sqlite3ReferencesSrcList().
+**
+** Set the 0x01 bit of pWalker->eCode if there is a reference to any
+** of the tables shown in RefSrcList.pRef.
+**
+** Set the 0x02 bit of pWalker->eCode if there is a reference to a
+** table is in neither RefSrcList.pRef nor RefSrcList.aiExclude.
+*/
+static int exprRefToSrcList(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_COLUMN
+   || pExpr->op==TK_AGG_COLUMN
+  ){
+    int i;
+    struct RefSrcList *p = pWalker->u.pRefSrcList;
+    SrcList *pSrc = p->pRef;
+    int nSrc = pSrc ? pSrc->nSrc : 0;
+    for(i=0; i<nSrc; i++){
+      if( pExpr->iTable==pSrc->a[i].iCursor ){
+        pWalker->eCode |= 1;
+        return WRC_Continue;
+      }
+    }
+    for(i=0; i<p->nExclude && p->aiExclude[i]!=pExpr->iTable; i++){}
+    if( i>=p->nExclude ){
+      pWalker->eCode |= 2;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Check to see if pExpr references any tables in pSrcList.
+** Possible return values:
+**
+**    1         pExpr does references a table in pSrcList.
+**
+**    0         pExpr references some table that is not defined in either
+**              pSrcList or in subqueries of pExpr itself.
+**
+**   -1         pExpr only references no tables at all, or it only
+**              references tables defined in subqueries of pExpr itself.
+**
+** As currently used, pExpr is always an aggregate function call.  That
+** fact is exploited for efficiency.
+*/
+SQLITE_PRIVATE int sqlite3ReferencesSrcList(Parse *pParse, Expr *pExpr, SrcList *pSrcList){
+  Walker w;
+  struct RefSrcList x;
+  assert( pParse->db!=0 );
+  memset(&w, 0, sizeof(w));
+  memset(&x, 0, sizeof(x));
+  w.xExprCallback = exprRefToSrcList;
+  w.xSelectCallback = selectRefEnter;
+  w.xSelectCallback2 = selectRefLeave;
+  w.u.pRefSrcList = &x;
+  x.db = pParse->db;
+  x.pRef = pSrcList;
+  assert( pExpr->op==TK_AGG_FUNCTION );
+  assert( ExprUseXList(pExpr) );
+  sqlite3WalkExprList(&w, pExpr->x.pList);
+  if( pExpr->pLeft ){
+    assert( pExpr->pLeft->op==TK_ORDER );
+    assert( ExprUseXList(pExpr->pLeft) );
+    assert( pExpr->pLeft->x.pList!=0 );
+    sqlite3WalkExprList(&w, pExpr->pLeft->x.pList);
+  }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( ExprHasProperty(pExpr, EP_WinFunc) ){
+    sqlite3WalkExpr(&w, pExpr->y.pWin->pFilter);
+  }
+#endif
+  if( x.aiExclude ) sqlite3DbNNFreeNN(pParse->db, x.aiExclude);
+  if( w.eCode & 0x01 ){
+    return 1;
+  }else if( w.eCode ){
+    return 0;
+  }else{
+    return -1;
+  }
+}
+
+/*
+** This is a Walker expression node callback.
+**
+** For Expr nodes that contain pAggInfo pointers, make sure the AggInfo
+** object that is referenced does not refer directly to the Expr.  If
+** it does, make a copy.  This is done because the pExpr argument is
+** subject to change.
+**
+** The copy is scheduled for deletion using the sqlite3ExprDeferredDelete()
+** which builds on the sqlite3ParserAddCleanup() mechanism.
+*/
+static int agginfoPersistExprCb(Walker *pWalker, Expr *pExpr){
+  if( ALWAYS(!ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced))
+   && pExpr->pAggInfo!=0
+  ){
+    AggInfo *pAggInfo = pExpr->pAggInfo;
+    int iAgg = pExpr->iAgg;
+    Parse *pParse = pWalker->pParse;
+    sqlite3 *db = pParse->db;
+    assert( iAgg>=0 );
+    if( pExpr->op!=TK_AGG_FUNCTION ){
+      if( iAgg<pAggInfo->nColumn
+       && pAggInfo->aCol[iAgg].pCExpr==pExpr
+      ){
+        pExpr = sqlite3ExprDup(db, pExpr, 0);
+        if( pExpr && !sqlite3ExprDeferredDelete(pParse, pExpr) ){
+          pAggInfo->aCol[iAgg].pCExpr = pExpr;
+        }
+      }
+    }else{
+      assert( pExpr->op==TK_AGG_FUNCTION );
+      if( ALWAYS(iAgg<pAggInfo->nFunc)
+       && pAggInfo->aFunc[iAgg].pFExpr==pExpr
+      ){
+        pExpr = sqlite3ExprDup(db, pExpr, 0);
+        if( pExpr && !sqlite3ExprDeferredDelete(pParse, pExpr) ){
+          pAggInfo->aFunc[iAgg].pFExpr = pExpr;
+        }
+      }
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Initialize a Walker object so that will persist AggInfo entries referenced
+** by the tree that is walked.
+*/
+SQLITE_PRIVATE void sqlite3AggInfoPersistWalkerInit(Walker *pWalker, Parse *pParse){
+  memset(pWalker, 0, sizeof(*pWalker));
+  pWalker->pParse = pParse;
+  pWalker->xExprCallback = agginfoPersistExprCb;
+  pWalker->xSelectCallback = sqlite3SelectWalkNoop;
+}
+
+/*
+** Add a new element to the pAggInfo->aCol[] array.  Return the index of
+** the new element.  Return a negative number if malloc fails.
+*/
+static int addAggInfoColumn(sqlite3 *db, AggInfo *pInfo){
+  int i;
+  pInfo->aCol = sqlite3ArrayAllocate(
+       db,
+       pInfo->aCol,
+       sizeof(pInfo->aCol[0]),
+       &pInfo->nColumn,
+       &i
+  );
+  return i;
+}
+
+/*
+** Add a new element to the pAggInfo->aFunc[] array.  Return the index of
+** the new element.  Return a negative number if malloc fails.
+*/
+static int addAggInfoFunc(sqlite3 *db, AggInfo *pInfo){
+  int i;
+  pInfo->aFunc = sqlite3ArrayAllocate(
+       db,
+       pInfo->aFunc,
+       sizeof(pInfo->aFunc[0]),
+       &pInfo->nFunc,
+       &i
+  );
+  return i;
+}
+
+/*
+** Search the AggInfo object for an aCol[] entry that has iTable and iColumn.
+** Return the index in aCol[] of the entry that describes that column.
+**
+** If no prior entry is found, create a new one and return -1.  The
+** new column will have an index of pAggInfo->nColumn-1.
+*/
+static void findOrCreateAggInfoColumn(
+  Parse *pParse,       /* Parsing context */
+  AggInfo *pAggInfo,   /* The AggInfo object to search and/or modify */
+  Expr *pExpr          /* Expr describing the column to find or insert */
+){
+  struct AggInfo_col *pCol;
+  int k;
+
+  assert( pAggInfo->iFirstReg==0 );
+  pCol = pAggInfo->aCol;
+  for(k=0; k<pAggInfo->nColumn; k++, pCol++){
+    if( pCol->pCExpr==pExpr ) return;
+    if( pCol->iTable==pExpr->iTable
+     && pCol->iColumn==pExpr->iColumn
+     && pExpr->op!=TK_IF_NULL_ROW
+    ){
+      goto fix_up_expr;
+    }
+  }
+  k = addAggInfoColumn(pParse->db, pAggInfo);
+  if( k<0 ){
+    /* OOM on resize */
+    assert( pParse->db->mallocFailed );
+    return;
+  }
+  pCol = &pAggInfo->aCol[k];
+  assert( ExprUseYTab(pExpr) );
+  pCol->pTab = pExpr->y.pTab;
+  pCol->iTable = pExpr->iTable;
+  pCol->iColumn = pExpr->iColumn;
+  pCol->iSorterColumn = -1;
+  pCol->pCExpr = pExpr;
+  if( pAggInfo->pGroupBy && pExpr->op!=TK_IF_NULL_ROW ){
+    int j, n;
+    ExprList *pGB = pAggInfo->pGroupBy;
+    struct ExprList_item *pTerm = pGB->a;
+    n = pGB->nExpr;
+    for(j=0; j<n; j++, pTerm++){
+      Expr *pE = pTerm->pExpr;
+      if( pE->op==TK_COLUMN
+       && pE->iTable==pExpr->iTable
+       && pE->iColumn==pExpr->iColumn
+      ){
+        pCol->iSorterColumn = j;
+        break;
+      }
+    }
+  }
+  if( pCol->iSorterColumn<0 ){
+    pCol->iSorterColumn = pAggInfo->nSortingColumn++;
+  }
+fix_up_expr:
+  ExprSetVVAProperty(pExpr, EP_NoReduce);
+  assert( pExpr->pAggInfo==0 || pExpr->pAggInfo==pAggInfo );
+  pExpr->pAggInfo = pAggInfo;
+  if( pExpr->op==TK_COLUMN ){
+    pExpr->op = TK_AGG_COLUMN;
+  }
+  pExpr->iAgg = (i16)k;
+}
+
+/*
+** This is the xExprCallback for a tree walker.  It is used to
+** implement sqlite3ExprAnalyzeAggregates().  See sqlite3ExprAnalyzeAggregates
+** for additional information.
+*/
+static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
+  int i;
+  NameContext *pNC = pWalker->u.pNC;
+  Parse *pParse = pNC->pParse;
+  SrcList *pSrcList = pNC->pSrcList;
+  AggInfo *pAggInfo = pNC->uNC.pAggInfo;
+
+  assert( pNC->ncFlags & NC_UAggInfo );
+  assert( pAggInfo->iFirstReg==0 );
+  switch( pExpr->op ){
+    default: {
+      IndexedExpr *pIEpr;
+      Expr tmp;
+      assert( pParse->iSelfTab==0 );
+      if( (pNC->ncFlags & NC_InAggFunc)==0 ) break;
+      if( pParse->pIdxEpr==0 ) break;
+      for(pIEpr=pParse->pIdxEpr; pIEpr; pIEpr=pIEpr->pIENext){
+        int iDataCur = pIEpr->iDataCur;
+        if( iDataCur<0 ) continue;
+        if( sqlite3ExprCompare(0, pExpr, pIEpr->pExpr, iDataCur)==0 ) break;
+      }
+      if( pIEpr==0 ) break;
+      if( NEVER(!ExprUseYTab(pExpr)) ) break;
+      for(i=0; i<pSrcList->nSrc; i++){
+         if( pSrcList->a[0].iCursor==pIEpr->iDataCur ) break;
+      }
+      if( i>=pSrcList->nSrc ) break;
+      if( NEVER(pExpr->pAggInfo!=0) ) break; /* Resolved by outer context */
+      if( pParse->nErr ){ return WRC_Abort; }
+
+      /* If we reach this point, it means that expression pExpr can be
+      ** translated into a reference to an index column as described by
+      ** pIEpr.
+      */
+      memset(&tmp, 0, sizeof(tmp));
+      tmp.op = TK_AGG_COLUMN;
+      tmp.iTable = pIEpr->iIdxCur;
+      tmp.iColumn = pIEpr->iIdxCol;
+      findOrCreateAggInfoColumn(pParse, pAggInfo, &tmp);
+      if( pParse->nErr ){ return WRC_Abort; }
+      assert( pAggInfo->aCol!=0 );
+      assert( tmp.iAgg<pAggInfo->nColumn );
+      pAggInfo->aCol[tmp.iAgg].pCExpr = pExpr;
+      pExpr->pAggInfo = pAggInfo;
+      pExpr->iAgg = tmp.iAgg;
+      return WRC_Prune;
+    }
+    case TK_IF_NULL_ROW:
+    case TK_AGG_COLUMN:
+    case TK_COLUMN: {
+      testcase( pExpr->op==TK_AGG_COLUMN );
+      testcase( pExpr->op==TK_COLUMN );
+      testcase( pExpr->op==TK_IF_NULL_ROW );
+      /* Check to see if the column is in one of the tables in the FROM
+      ** clause of the aggregate query */
+      if( ALWAYS(pSrcList!=0) ){
+        SrcItem *pItem = pSrcList->a;
+        for(i=0; i<pSrcList->nSrc; i++, pItem++){
+          assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+          if( pExpr->iTable==pItem->iCursor ){
+            findOrCreateAggInfoColumn(pParse, pAggInfo, pExpr);
+            break;
+          } /* endif pExpr->iTable==pItem->iCursor */
+        } /* end loop over pSrcList */
+      }
+      return WRC_Continue;
+    }
+    case TK_AGG_FUNCTION: {
+      if( (pNC->ncFlags & NC_InAggFunc)==0
+       && pWalker->walkerDepth==pExpr->op2
+       && pExpr->pAggInfo==0
+      ){
+        /* Check to see if pExpr is a duplicate of another aggregate
+        ** function that is already in the pAggInfo structure
+        */
+        struct AggInfo_func *pItem = pAggInfo->aFunc;
+        for(i=0; i<pAggInfo->nFunc; i++, pItem++){
+          if( NEVER(pItem->pFExpr==pExpr) ) break;
+          if( sqlite3ExprCompare(0, pItem->pFExpr, pExpr, -1)==0 ){
+            break;
+          }
+        }
+        if( i>=pAggInfo->nFunc ){
+          /* pExpr is original.  Make a new entry in pAggInfo->aFunc[]
+          */
+          u8 enc = ENC(pParse->db);
+          i = addAggInfoFunc(pParse->db, pAggInfo);
+          if( i>=0 ){
+            int nArg;
+            assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+            pItem = &pAggInfo->aFunc[i];
+            pItem->pFExpr = pExpr;
+            assert( ExprUseUToken(pExpr) );
+            nArg = pExpr->x.pList ? pExpr->x.pList->nExpr : 0;
+            pItem->pFunc = sqlite3FindFunction(pParse->db,
+                                         pExpr->u.zToken, nArg, enc, 0);
+            assert( pItem->bOBUnique==0 );
+            if( pExpr->pLeft
+             && (pItem->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL)==0
+            ){
+              /* The NEEDCOLL test above causes any ORDER BY clause on
+              ** aggregate min() or max() to be ignored. */
+              ExprList *pOBList;
+              assert( nArg>0 );
+              assert( pExpr->pLeft->op==TK_ORDER );
+              assert( ExprUseXList(pExpr->pLeft) );
+              pItem->iOBTab = pParse->nTab++;
+              pOBList = pExpr->pLeft->x.pList;
+              assert( pOBList->nExpr>0 );
+              assert( pItem->bOBUnique==0 );
+              if( pOBList->nExpr==1
+               && nArg==1
+               && sqlite3ExprCompare(0,pOBList->a[0].pExpr,
+                               pExpr->x.pList->a[0].pExpr,0)==0
+              ){
+                pItem->bOBPayload = 0;
+                pItem->bOBUnique = ExprHasProperty(pExpr, EP_Distinct);
+              }else{
+                pItem->bOBPayload = 1;
+              }
+              pItem->bUseSubtype =
+                    (pItem->pFunc->funcFlags & SQLITE_SUBTYPE)!=0;
+            }else{
+              pItem->iOBTab = -1;
+            }
+            if( ExprHasProperty(pExpr, EP_Distinct) && !pItem->bOBUnique ){
+              pItem->iDistinct = pParse->nTab++;
+            }else{
+              pItem->iDistinct = -1;
+            }
+          }
+        }
+        /* Make pExpr point to the appropriate pAggInfo->aFunc[] entry
+        */
+        assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
+        ExprSetVVAProperty(pExpr, EP_NoReduce);
+        pExpr->iAgg = (i16)i;
+        pExpr->pAggInfo = pAggInfo;
+        return WRC_Prune;
+      }else{
+        return WRC_Continue;
+      }
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Analyze the pExpr expression looking for aggregate functions and
+** for variables that need to be added to AggInfo object that pNC->pAggInfo
+** points to.  Additional entries are made on the AggInfo object as
+** necessary.
+**
+** This routine should only be called after the expression has been
+** analyzed by sqlite3ResolveExprNames().
+*/
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
+  Walker w;
+  w.xExprCallback = analyzeAggregate;
+  w.xSelectCallback = sqlite3WalkerDepthIncrease;
+  w.xSelectCallback2 = sqlite3WalkerDepthDecrease;
+  w.walkerDepth = 0;
+  w.u.pNC = pNC;
+  w.pParse = 0;
+  assert( pNC->pSrcList!=0 );
+  sqlite3WalkExpr(&w, pExpr);
+}
+
+/*
+** Call sqlite3ExprAnalyzeAggregates() for every expression in an
+** expression list.  Return the number of errors.
+**
+** If an error is found, the analysis is cut short.
+*/
+SQLITE_PRIVATE void sqlite3ExprAnalyzeAggList(NameContext *pNC, ExprList *pList){
+  struct ExprList_item *pItem;
+  int i;
+  if( pList ){
+    for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
+      sqlite3ExprAnalyzeAggregates(pNC, pItem->pExpr);
+    }
+  }
+}
+
+/*
+** Allocate a single new register for use to hold some intermediate result.
+*/
+SQLITE_PRIVATE int sqlite3GetTempReg(Parse *pParse){
+  if( pParse->nTempReg==0 ){
+    return ++pParse->nMem;
+  }
+  return pParse->aTempReg[--pParse->nTempReg];
+}
+
+/*
+** Deallocate a register, making available for reuse for some other
+** purpose.
+*/
+SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
+  if( iReg ){
+    sqlite3VdbeReleaseRegisters(pParse, iReg, 1, 0, 0);
+    if( pParse->nTempReg<ArraySize(pParse->aTempReg) ){
+      pParse->aTempReg[pParse->nTempReg++] = iReg;
+    }
+  }
+}
+
+/*
+** Allocate or deallocate a block of nReg consecutive registers.
+*/
+SQLITE_PRIVATE int sqlite3GetTempRange(Parse *pParse, int nReg){
+  int i, n;
+  if( nReg==1 ) return sqlite3GetTempReg(pParse);
+  i = pParse->iRangeReg;
+  n = pParse->nRangeReg;
+  if( nReg<=n ){
+    pParse->iRangeReg += nReg;
+    pParse->nRangeReg -= nReg;
+  }else{
+    i = pParse->nMem+1;
+    pParse->nMem += nReg;
+  }
+  return i;
+}
+SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse *pParse, int iReg, int nReg){
+  if( nReg==1 ){
+    sqlite3ReleaseTempReg(pParse, iReg);
+    return;
+  }
+  sqlite3VdbeReleaseRegisters(pParse, iReg, nReg, 0, 0);
+  if( nReg>pParse->nRangeReg ){
+    pParse->nRangeReg = nReg;
+    pParse->iRangeReg = iReg;
+  }
+}
+
+/*
+** Mark all temporary registers as being unavailable for reuse.
+**
+** Always invoke this procedure after coding a subroutine or co-routine
+** that might be invoked from other parts of the code, to ensure that
+** the sub/co-routine does not use registers in common with the code that
+** invokes the sub/co-routine.
+*/
+SQLITE_PRIVATE void sqlite3ClearTempRegCache(Parse *pParse){
+  pParse->nTempReg = 0;
+  pParse->nRangeReg = 0;
+}
+
+/*
+** Make sure sufficient registers have been allocated so that
+** iReg is a valid register number.
+*/
+SQLITE_PRIVATE void sqlite3TouchRegister(Parse *pParse, int iReg){
+  if( pParse->nMem<iReg ) pParse->nMem = iReg;
+}
+
+#if defined(SQLITE_ENABLE_STAT4) || defined(SQLITE_DEBUG)
+/*
+** Return the latest reusable register in the set of all registers.
+** The value returned is no less than iMin.  If any register iMin or
+** greater is in permanent use, then return one more than that last
+** permanent register.
+*/
+SQLITE_PRIVATE int sqlite3FirstAvailableRegister(Parse *pParse, int iMin){
+  const ExprList *pList = pParse->pConstExpr;
+  if( pList ){
+    int i;
+    for(i=0; i<pList->nExpr; i++){
+      if( pList->a[i].u.iConstExprReg>=iMin ){
+        iMin = pList->a[i].u.iConstExprReg + 1;
+      }
+    }
+  }
+  pParse->nTempReg = 0;
+  pParse->nRangeReg = 0;
+  return iMin;
+}
+#endif /* SQLITE_ENABLE_STAT4 || SQLITE_DEBUG */
+
+/*
+** Validate that no temporary register falls within the range of
+** iFirst..iLast, inclusive.  This routine is only call from within assert()
+** statements.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3NoTempsInRange(Parse *pParse, int iFirst, int iLast){
+  int i;
+  if( pParse->nRangeReg>0
+   && pParse->iRangeReg+pParse->nRangeReg > iFirst
+   && pParse->iRangeReg <= iLast
+  ){
+     return 0;
+  }
+  for(i=0; i<pParse->nTempReg; i++){
+    if( pParse->aTempReg[i]>=iFirst && pParse->aTempReg[i]<=iLast ){
+      return 0;
+    }
+  }
+  if( pParse->pConstExpr ){
+    ExprList *pList = pParse->pConstExpr;
+    for(i=0; i<pList->nExpr; i++){
+      int iReg = pList->a[i].u.iConstExprReg;
+      if( iReg==0 ) continue;
+      if( iReg>=iFirst && iReg<=iLast ) return 0;
+    }
+  }
+  return 1;
+}
+#endif /* SQLITE_DEBUG */
+
+/************** End of expr.c ************************************************/
+/************** Begin file alter.c *******************************************/
+/*
+** 2005 February 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that used to generate VDBE code
+** that implements the ALTER TABLE command.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** The code in this file only exists if we are not omitting the
+** ALTER TABLE logic from the build.
+*/
+#ifndef SQLITE_OMIT_ALTERTABLE
+
+/*
+** Parameter zName is the name of a table that is about to be altered
+** (either with ALTER TABLE ... RENAME TO or ALTER TABLE ... ADD COLUMN).
+** If the table is a system table, this function leaves an error message
+** in pParse->zErr (system tables may not be altered) and returns non-zero.
+**
+** Or, if zName is not a system table, zero is returned.
+*/
+static int isAlterableTable(Parse *pParse, Table *pTab){
+  if( 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7)
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+   || (pTab->tabFlags & TF_Eponymous)!=0
+   || ( (pTab->tabFlags & TF_Shadow)!=0
+        && sqlite3ReadOnlyShadowTables(pParse->db)
+   )
+#endif
+  ){
+    sqlite3ErrorMsg(pParse, "table %s may not be altered", pTab->zName);
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Generate code to verify that the schemas of database zDb and, if
+** bTemp is not true, database "temp", can still be parsed. This is
+** called at the end of the generation of an ALTER TABLE ... RENAME ...
+** statement to ensure that the operation has not rendered any schema
+** objects unusable.
+*/
+static void renameTestSchema(
+  Parse *pParse,                  /* Parse context */
+  const char *zDb,                /* Name of db to verify schema of */
+  int bTemp,                      /* True if this is the temp db */
+  const char *zWhen,              /* "when" part of error message */
+  int bNoDQS                      /* Do not allow DQS in the schema */
+){
+  pParse->colNamesSet = 1;
+  sqlite3NestedParse(pParse,
+      "SELECT 1 "
+      "FROM \"%w\"." LEGACY_SCHEMA_TABLE " "
+      "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+      " AND sql NOT LIKE 'create virtual%%'"
+      " AND sqlite_rename_test(%Q, sql, type, name, %d, %Q, %d)=NULL ",
+      zDb,
+      zDb, bTemp, zWhen, bNoDQS
+  );
+
+  if( bTemp==0 ){
+    sqlite3NestedParse(pParse,
+        "SELECT 1 "
+        "FROM temp." LEGACY_SCHEMA_TABLE " "
+        "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+        " AND sql NOT LIKE 'create virtual%%'"
+        " AND sqlite_rename_test(%Q, sql, type, name, 1, %Q, %d)=NULL ",
+        zDb, zWhen, bNoDQS
+    );
+  }
+}
+
+/*
+** Generate VM code to replace any double-quoted strings (but not double-quoted
+** identifiers) within the "sql" column of the sqlite_schema table in
+** database zDb with their single-quoted equivalents. If argument bTemp is
+** not true, similarly update all SQL statements in the sqlite_schema table
+** of the temp db.
+*/
+static void renameFixQuotes(Parse *pParse, const char *zDb, int bTemp){
+  sqlite3NestedParse(pParse,
+      "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE
+      " SET sql = sqlite_rename_quotefix(%Q, sql)"
+      "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+      " AND sql NOT LIKE 'create virtual%%'" , zDb, zDb
+  );
+  if( bTemp==0 ){
+    sqlite3NestedParse(pParse,
+      "UPDATE temp." LEGACY_SCHEMA_TABLE
+      " SET sql = sqlite_rename_quotefix('temp', sql)"
+      "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+      " AND sql NOT LIKE 'create virtual%%'"
+    );
+  }
+}
+
+/*
+** Generate code to reload the schema for database iDb. And, if iDb!=1, for
+** the temp database as well.
+*/
+static void renameReloadSchema(Parse *pParse, int iDb, u16 p5){
+  Vdbe *v = pParse->pVdbe;
+  if( v ){
+    sqlite3ChangeCookie(pParse, iDb);
+    sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, iDb, 0, p5);
+    if( iDb!=1 ) sqlite3VdbeAddParseSchemaOp(pParse->pVdbe, 1, 0, p5);
+  }
+}
+
+/*
+** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy"
+** command.
+*/
+SQLITE_PRIVATE void sqlite3AlterRenameTable(
+  Parse *pParse,            /* Parser context. */
+  SrcList *pSrc,            /* The table to rename. */
+  Token *pName              /* The new table name. */
+){
+  int iDb;                  /* Database that contains the table */
+  char *zDb;                /* Name of database iDb */
+  Table *pTab;              /* Table being renamed */
+  char *zName = 0;          /* NULL-terminated version of pName */
+  sqlite3 *db = pParse->db; /* Database connection */
+  int nTabName;             /* Number of UTF-8 characters in zTabName */
+  const char *zTabName;     /* Original name of the table */
+  Vdbe *v;
+  VTable *pVTab = 0;        /* Non-zero if this is a v-tab with an xRename() */
+
+  if( NEVER(db->mallocFailed) ) goto exit_rename_table;
+  assert( pSrc->nSrc==1 );
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+
+  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
+  if( !pTab ) goto exit_rename_table;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  zDb = db->aDb[iDb].zDbSName;
+
+  /* Get a NULL terminated version of the new table name. */
+  zName = sqlite3NameFromToken(db, pName);
+  if( !zName ) goto exit_rename_table;
+
+  /* Check that a table or index named 'zName' does not already exist
+  ** in database iDb. If so, this is an error.
+  */
+  if( sqlite3FindTable(db, zName, zDb)
+   || sqlite3FindIndex(db, zName, zDb)
+   || sqlite3IsShadowTableOf(db, pTab, zName)
+  ){
+    sqlite3ErrorMsg(pParse,
+        "there is already another table or index with this name: %s", zName);
+    goto exit_rename_table;
+  }
+
+  /* Make sure it is not a system table being altered, or a reserved name
+  ** that the table is being renamed to.
+  */
+  if( SQLITE_OK!=isAlterableTable(pParse, pTab) ){
+    goto exit_rename_table;
+  }
+  if( SQLITE_OK!=sqlite3CheckObjectName(pParse,zName,"table",zName) ){
+    goto exit_rename_table;
+  }
+
+#ifndef SQLITE_OMIT_VIEW
+  if( IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "view %s may not be altered", pTab->zName);
+    goto exit_rename_table;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
+    goto exit_rename_table;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto exit_rename_table;
+  }
+  if( IsVirtual(pTab) ){
+    pVTab = sqlite3GetVTable(db, pTab);
+    if( pVTab->pVtab->pModule->xRename==0 ){
+      pVTab = 0;
+    }
+  }
+#endif
+
+  /* Begin a transaction for database iDb. Then modify the schema cookie
+  ** (since the ALTER TABLE modifies the schema). Call sqlite3MayAbort(),
+  ** as the scalar functions (e.g. sqlite_rename_table()) invoked by the
+  ** nested SQL may raise an exception.  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ){
+    goto exit_rename_table;
+  }
+  sqlite3MayAbort(pParse);
+
+  /* figure out how many UTF-8 characters are in zName */
+  zTabName = pTab->zName;
+  nTabName = sqlite3Utf8CharLen(zTabName, -1);
+
+  /* Rewrite all CREATE TABLE, INDEX, TRIGGER or VIEW statements in
+  ** the schema to use the new table name.  */
+  sqlite3NestedParse(pParse,
+      "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE " SET "
+      "sql = sqlite_rename_table(%Q, type, name, sql, %Q, %Q, %d) "
+      "WHERE (type!='index' OR tbl_name=%Q COLLATE nocase)"
+      "AND   name NOT LIKE 'sqliteX_%%' ESCAPE 'X'"
+      , zDb, zDb, zTabName, zName, (iDb==1), zTabName
+  );
+
+  /* Update the tbl_name and name columns of the sqlite_schema table
+  ** as required.  */
+  sqlite3NestedParse(pParse,
+      "UPDATE %Q." LEGACY_SCHEMA_TABLE " SET "
+          "tbl_name = %Q, "
+          "name = CASE "
+            "WHEN type='table' THEN %Q "
+            "WHEN name LIKE 'sqliteX_autoindex%%' ESCAPE 'X' "
+            "     AND type='index' THEN "
+             "'sqlite_autoindex_' || %Q || substr(name,%d+18) "
+            "ELSE name END "
+      "WHERE tbl_name=%Q COLLATE nocase AND "
+          "(type='table' OR type='index' OR type='trigger');",
+      zDb,
+      zName, zName, zName,
+      nTabName, zTabName
+  );
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+  /* If the sqlite_sequence table exists in this database, then update
+  ** it with the new table name.
+  */
+  if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
+    sqlite3NestedParse(pParse,
+        "UPDATE \"%w\".sqlite_sequence set name = %Q WHERE name = %Q",
+        zDb, zName, pTab->zName);
+  }
+#endif
+
+  /* If the table being renamed is not itself part of the temp database,
+  ** edit view and trigger definitions within the temp database
+  ** as required.  */
+  if( iDb!=1 ){
+    sqlite3NestedParse(pParse,
+        "UPDATE sqlite_temp_schema SET "
+            "sql = sqlite_rename_table(%Q, type, name, sql, %Q, %Q, 1), "
+            "tbl_name = "
+              "CASE WHEN tbl_name=%Q COLLATE nocase AND "
+              "  sqlite_rename_test(%Q, sql, type, name, 1, 'after rename', 0) "
+              "THEN %Q ELSE tbl_name END "
+            "WHERE type IN ('view', 'trigger')"
+        , zDb, zTabName, zName, zTabName, zDb, zName);
+  }
+
+  /* If this is a virtual table, invoke the xRename() function if
+  ** one is defined. The xRename() callback will modify the names
+  ** of any resources used by the v-table implementation (including other
+  ** SQLite tables) that are identified by the name of the virtual table.
+  */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( pVTab ){
+    int i = ++pParse->nMem;
+    sqlite3VdbeLoadString(v, i, zName);
+    sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0,(const char*)pVTab, P4_VTAB);
+  }
+#endif
+
+  renameReloadSchema(pParse, iDb, INITFLAG_AlterRename);
+  renameTestSchema(pParse, zDb, iDb==1, "after rename", 0);
+
+exit_rename_table:
+  sqlite3SrcListDelete(db, pSrc);
+  sqlite3DbFree(db, zName);
+}
+
+/*
+** Write code that will raise an error if the table described by
+** zDb and zTab is not empty.
+*/
+static void sqlite3ErrorIfNotEmpty(
+  Parse *pParse,        /* Parsing context */
+  const char *zDb,      /* Schema holding the table */
+  const char *zTab,     /* Table to check for empty */
+  const char *zErr      /* Error message text */
+){
+  sqlite3NestedParse(pParse,
+     "SELECT raise(ABORT,%Q) FROM \"%w\".\"%w\"",
+     zErr, zDb, zTab
+  );
+}
+
+/*
+** This function is called after an "ALTER TABLE ... ADD" statement
+** has been parsed. Argument pColDef contains the text of the new
+** column definition.
+**
+** The Table structure pParse->pNewTable was extended to include
+** the new column during parsing.
+*/
+SQLITE_PRIVATE void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
+  Table *pNew;              /* Copy of pParse->pNewTable */
+  Table *pTab;              /* Table being altered */
+  int iDb;                  /* Database number */
+  const char *zDb;          /* Database name */
+  const char *zTab;         /* Table name */
+  char *zCol;               /* Null-terminated column definition */
+  Column *pCol;             /* The new column */
+  Expr *pDflt;              /* Default value for the new column */
+  sqlite3 *db;              /* The database connection; */
+  Vdbe *v;                  /* The prepared statement under construction */
+  int r1;                   /* Temporary registers */
+
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nErr ) return;
+  assert( db->mallocFailed==0 );
+  pNew = pParse->pNewTable;
+  assert( pNew );
+
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  iDb = sqlite3SchemaToIndex(db, pNew->pSchema);
+  zDb = db->aDb[iDb].zDbSName;
+  zTab = &pNew->zName[16];  /* Skip the "sqlite_altertab_" prefix on the name */
+  pCol = &pNew->aCol[pNew->nCol-1];
+  pDflt = sqlite3ColumnExpr(pNew, pCol);
+  pTab = sqlite3FindTable(db, zTab, zDb);
+  assert( pTab );
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
+    return;
+  }
+#endif
+
+
+  /* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
+  ** If there is a NOT NULL constraint, then the default value for the
+  ** column must not be NULL.
+  */
+  if( pCol->colFlags & COLFLAG_PRIMKEY ){
+    sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
+    return;
+  }
+  if( pNew->pIndex ){
+    sqlite3ErrorMsg(pParse,
+         "Cannot add a UNIQUE column");
+    return;
+  }
+  if( (pCol->colFlags & COLFLAG_GENERATED)==0 ){
+    /* If the default value for the new column was specified with a
+    ** literal NULL, then set pDflt to 0. This simplifies checking
+    ** for an SQL NULL default below.
+    */
+    assert( pDflt==0 || pDflt->op==TK_SPAN );
+    if( pDflt && pDflt->pLeft->op==TK_NULL ){
+      pDflt = 0;
+    }
+    assert( IsOrdinaryTable(pNew) );
+    if( (db->flags&SQLITE_ForeignKeys) && pNew->u.tab.pFKey && pDflt ){
+      sqlite3ErrorIfNotEmpty(pParse, zDb, zTab,
+          "Cannot add a REFERENCES column with non-NULL default value");
+    }
+    if( pCol->notNull && !pDflt ){
+      sqlite3ErrorIfNotEmpty(pParse, zDb, zTab,
+          "Cannot add a NOT NULL column with default value NULL");
+    }
+
+
+    /* Ensure the default expression is something that sqlite3ValueFromExpr()
+    ** can handle (i.e. not CURRENT_TIME etc.)
+    */
+    if( pDflt ){
+      sqlite3_value *pVal = 0;
+      int rc;
+      rc = sqlite3ValueFromExpr(db, pDflt, SQLITE_UTF8, SQLITE_AFF_BLOB, &pVal);
+      assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
+      if( rc!=SQLITE_OK ){
+        assert( db->mallocFailed == 1 );
+        return;
+      }
+      if( !pVal ){
+        sqlite3ErrorIfNotEmpty(pParse, zDb, zTab,
+           "Cannot add a column with non-constant default");
+      }
+      sqlite3ValueFree(pVal);
+    }
+  }else if( pCol->colFlags & COLFLAG_STORED ){
+    sqlite3ErrorIfNotEmpty(pParse, zDb, zTab, "cannot add a STORED column");
+  }
+
+
+  /* Modify the CREATE TABLE statement. */
+  zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
+  if( zCol ){
+    char *zEnd = &zCol[pColDef->n-1];
+    while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
+      *zEnd-- = '\0';
+    }
+    /* substr() operations on characters, but addColOffset is in bytes. So we
+    ** have to use printf() to translate between these units: */
+    assert( IsOrdinaryTable(pTab) );
+    assert( IsOrdinaryTable(pNew) );
+    sqlite3NestedParse(pParse,
+        "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE " SET "
+          "sql = printf('%%.%ds, ',sql) || %Q"
+          " || substr(sql,1+length(printf('%%.%ds',sql))) "
+        "WHERE type = 'table' AND name = %Q",
+      zDb, pNew->u.tab.addColOffset, zCol, pNew->u.tab.addColOffset,
+      zTab
+    );
+    sqlite3DbFree(db, zCol);
+  }
+
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    /* Make sure the schema version is at least 3.  But do not upgrade
+    ** from less than 3 to 4, as that will corrupt any preexisting DESC
+    ** index.
+    */
+    r1 = sqlite3GetTempReg(pParse);
+    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, BTREE_FILE_FORMAT);
+    sqlite3VdbeUsesBtree(v, iDb);
+    sqlite3VdbeAddOp2(v, OP_AddImm, r1, -2);
+    sqlite3VdbeAddOp2(v, OP_IfPos, r1, sqlite3VdbeCurrentAddr(v)+2);
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, 3);
+    sqlite3ReleaseTempReg(pParse, r1);
+
+    /* Reload the table definition */
+    renameReloadSchema(pParse, iDb, INITFLAG_AlterAdd);
+
+    /* Verify that constraints are still satisfied */
+    if( pNew->pCheck!=0
+     || (pCol->notNull && (pCol->colFlags & COLFLAG_GENERATED)!=0)
+     || (pTab->tabFlags & TF_Strict)!=0
+    ){
+      sqlite3NestedParse(pParse,
+        "SELECT CASE WHEN quick_check GLOB 'CHECK*'"
+        " THEN raise(ABORT,'CHECK constraint failed')"
+        " WHEN quick_check GLOB 'non-* value in*'"
+        " THEN raise(ABORT,'type mismatch on DEFAULT')"
+        " ELSE raise(ABORT,'NOT NULL constraint failed')"
+        " END"
+        "  FROM pragma_quick_check(%Q,%Q)"
+        " WHERE quick_check GLOB 'CHECK*'"
+        " OR quick_check GLOB 'NULL*'"
+        " OR quick_check GLOB 'non-* value in*'",
+        zTab, zDb
+      );
+    }
+  }
+}
+
+/*
+** This function is called by the parser after the table-name in
+** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument
+** pSrc is the full-name of the table being altered.
+**
+** This routine makes a (partial) copy of the Table structure
+** for the table being altered and sets Parse.pNewTable to point
+** to it. Routines called by the parser as the column definition
+** is parsed (i.e. sqlite3AddColumn()) add the new Column data to
+** the copy. The copy of the Table structure is deleted by tokenize.c
+** after parsing is finished.
+**
+** Routine sqlite3AlterFinishAddColumn() will be called to complete
+** coding the "ALTER TABLE ... ADD" statement.
+*/
+SQLITE_PRIVATE void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
+  Table *pNew;
+  Table *pTab;
+  int iDb;
+  int i;
+  int nAlloc;
+  sqlite3 *db = pParse->db;
+
+  /* Look up the table being altered. */
+  assert( pParse->pNewTable==0 );
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  if( db->mallocFailed ) goto exit_begin_add_column;
+  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
+  if( !pTab ) goto exit_begin_add_column;
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
+    goto exit_begin_add_column;
+  }
+#endif
+
+  /* Make sure this is not an attempt to ALTER a view. */
+  if( IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
+    goto exit_begin_add_column;
+  }
+  if( SQLITE_OK!=isAlterableTable(pParse, pTab) ){
+    goto exit_begin_add_column;
+  }
+
+  sqlite3MayAbort(pParse);
+  assert( IsOrdinaryTable(pTab) );
+  assert( pTab->u.tab.addColOffset>0 );
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+
+  /* Put a copy of the Table struct in Parse.pNewTable for the
+  ** sqlite3AddColumn() function and friends to modify.  But modify
+  ** the name by adding an "sqlite_altertab_" prefix.  By adding this
+  ** prefix, we insure that the name will not collide with an existing
+  ** table because user table are not allowed to have the "sqlite_"
+  ** prefix on their name.
+  */
+  pNew = (Table*)sqlite3DbMallocZero(db, sizeof(Table));
+  if( !pNew ) goto exit_begin_add_column;
+  pParse->pNewTable = pNew;
+  pNew->nTabRef = 1;
+  pNew->nCol = pTab->nCol;
+  assert( pNew->nCol>0 );
+  nAlloc = (((pNew->nCol-1)/8)*8)+8;
+  assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
+  pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*nAlloc);
+  pNew->zName = sqlite3MPrintf(db, "sqlite_altertab_%s", pTab->zName);
+  if( !pNew->aCol || !pNew->zName ){
+    assert( db->mallocFailed );
+    goto exit_begin_add_column;
+  }
+  memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
+  for(i=0; i<pNew->nCol; i++){
+    Column *pCol = &pNew->aCol[i];
+    pCol->zCnName = sqlite3DbStrDup(db, pCol->zCnName);
+    pCol->hName = sqlite3StrIHash(pCol->zCnName);
+  }
+  assert( IsOrdinaryTable(pNew) );
+  pNew->u.tab.pDfltList = sqlite3ExprListDup(db, pTab->u.tab.pDfltList, 0);
+  pNew->pSchema = db->aDb[iDb].pSchema;
+  pNew->u.tab.addColOffset = pTab->u.tab.addColOffset;
+  assert( pNew->nTabRef==1 );
+
+exit_begin_add_column:
+  sqlite3SrcListDelete(db, pSrc);
+  return;
+}
+
+/*
+** Parameter pTab is the subject of an ALTER TABLE ... RENAME COLUMN
+** command. This function checks if the table is a view or virtual
+** table (columns of views or virtual tables may not be renamed). If so,
+** it loads an error message into pParse and returns non-zero.
+**
+** Or, if pTab is not a view or virtual table, zero is returned.
+*/
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+static int isRealTable(Parse *pParse, Table *pTab, int bDrop){
+  const char *zType = 0;
+#ifndef SQLITE_OMIT_VIEW
+  if( IsView(pTab) ){
+    zType = "view";
+  }
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    zType = "virtual table";
+  }
+#endif
+  if( zType ){
+    sqlite3ErrorMsg(pParse, "cannot %s %s \"%s\"",
+        (bDrop ? "drop column from" : "rename columns of"),
+        zType, pTab->zName
+    );
+    return 1;
+  }
+  return 0;
+}
+#else /* !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE) */
+# define isRealTable(x,y,z) (0)
+#endif
+
+/*
+** Handles the following parser reduction:
+**
+**  cmd ::= ALTER TABLE pSrc RENAME COLUMN pOld TO pNew
+*/
+SQLITE_PRIVATE void sqlite3AlterRenameColumn(
+  Parse *pParse,                  /* Parsing context */
+  SrcList *pSrc,                  /* Table being altered.  pSrc->nSrc==1 */
+  Token *pOld,                    /* Name of column being changed */
+  Token *pNew                     /* New column name */
+){
+  sqlite3 *db = pParse->db;       /* Database connection */
+  Table *pTab;                    /* Table being updated */
+  int iCol;                       /* Index of column being renamed */
+  char *zOld = 0;                 /* Old column name */
+  char *zNew = 0;                 /* New column name */
+  const char *zDb;                /* Name of schema containing the table */
+  int iSchema;                    /* Index of the schema */
+  int bQuote;                     /* True to quote the new name */
+
+  /* Locate the table to be altered */
+  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
+  if( !pTab ) goto exit_rename_column;
+
+  /* Cannot alter a system table */
+  if( SQLITE_OK!=isAlterableTable(pParse, pTab) ) goto exit_rename_column;
+  if( SQLITE_OK!=isRealTable(pParse, pTab, 0) ) goto exit_rename_column;
+
+  /* Which schema holds the table to be altered */
+  iSchema = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iSchema>=0 );
+  zDb = db->aDb[iSchema].zDbSName;
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
+    goto exit_rename_column;
+  }
+#endif
+
+  /* Make sure the old name really is a column name in the table to be
+  ** altered.  Set iCol to be the index of the column being renamed */
+  zOld = sqlite3NameFromToken(db, pOld);
+  if( !zOld ) goto exit_rename_column;
+  for(iCol=0; iCol<pTab->nCol; iCol++){
+    if( 0==sqlite3StrICmp(pTab->aCol[iCol].zCnName, zOld) ) break;
+  }
+  if( iCol==pTab->nCol ){
+    sqlite3ErrorMsg(pParse, "no such column: \"%T\"", pOld);
+    goto exit_rename_column;
+  }
+
+  /* Ensure the schema contains no double-quoted strings */
+  renameTestSchema(pParse, zDb, iSchema==1, "", 0);
+  renameFixQuotes(pParse, zDb, iSchema==1);
+
+  /* Do the rename operation using a recursive UPDATE statement that
+  ** uses the sqlite_rename_column() SQL function to compute the new
+  ** CREATE statement text for the sqlite_schema table.
+  */
+  sqlite3MayAbort(pParse);
+  zNew = sqlite3NameFromToken(db, pNew);
+  if( !zNew ) goto exit_rename_column;
+  assert( pNew->n>0 );
+  bQuote = sqlite3Isquote(pNew->z[0]);
+  sqlite3NestedParse(pParse,
+      "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE " SET "
+      "sql = sqlite_rename_column(sql, type, name, %Q, %Q, %d, %Q, %d, %d) "
+      "WHERE name NOT LIKE 'sqliteX_%%' ESCAPE 'X' "
+      " AND (type != 'index' OR tbl_name = %Q)",
+      zDb,
+      zDb, pTab->zName, iCol, zNew, bQuote, iSchema==1,
+      pTab->zName
+  );
+
+  sqlite3NestedParse(pParse,
+      "UPDATE temp." LEGACY_SCHEMA_TABLE " SET "
+      "sql = sqlite_rename_column(sql, type, name, %Q, %Q, %d, %Q, %d, 1) "
+      "WHERE type IN ('trigger', 'view')",
+      zDb, pTab->zName, iCol, zNew, bQuote
+  );
+
+  /* Drop and reload the database schema. */
+  renameReloadSchema(pParse, iSchema, INITFLAG_AlterRename);
+  renameTestSchema(pParse, zDb, iSchema==1, "after rename", 1);
+
+ exit_rename_column:
+  sqlite3SrcListDelete(db, pSrc);
+  sqlite3DbFree(db, zOld);
+  sqlite3DbFree(db, zNew);
+  return;
+}
+
+/*
+** Each RenameToken object maps an element of the parse tree into
+** the token that generated that element.  The parse tree element
+** might be one of:
+**
+**     *  A pointer to an Expr that represents an ID
+**     *  The name of a table column in Column.zName
+**
+** A list of RenameToken objects can be constructed during parsing.
+** Each new object is created by sqlite3RenameTokenMap().
+** As the parse tree is transformed, the sqlite3RenameTokenRemap()
+** routine is used to keep the mapping current.
+**
+** After the parse finishes, renameTokenFind() routine can be used
+** to look up the actual token value that created some element in
+** the parse tree.
+*/
+struct RenameToken {
+  const void *p;         /* Parse tree element created by token t */
+  Token t;               /* The token that created parse tree element p */
+  RenameToken *pNext;    /* Next is a list of all RenameToken objects */
+};
+
+/*
+** The context of an ALTER TABLE RENAME COLUMN operation that gets passed
+** down into the Walker.
+*/
+typedef struct RenameCtx RenameCtx;
+struct RenameCtx {
+  RenameToken *pList;             /* List of tokens to overwrite */
+  int nList;                      /* Number of tokens in pList */
+  int iCol;                       /* Index of column being renamed */
+  Table *pTab;                    /* Table being ALTERed */
+  const char *zOld;               /* Old column name */
+};
+
+#ifdef SQLITE_DEBUG
+/*
+** This function is only for debugging. It performs two tasks:
+**
+**   1. Checks that pointer pPtr does not already appear in the
+**      rename-token list.
+**
+**   2. Dereferences each pointer in the rename-token list.
+**
+** The second is most effective when debugging under valgrind or
+** address-sanitizer or similar. If any of these pointers no longer
+** point to valid objects, an exception is raised by the memory-checking
+** tool.
+**
+** The point of this is to prevent comparisons of invalid pointer values.
+** Even though this always seems to work, it is undefined according to the
+** C standard. Example of undefined comparison:
+**
+**     sqlite3_free(x);
+**     if( x==y ) ...
+**
+** Technically, as x no longer points into a valid object or to the byte
+** following a valid object, it may not be used in comparison operations.
+*/
+static void renameTokenCheckAll(Parse *pParse, const void *pPtr){
+  assert( pParse==pParse->db->pParse );
+  assert( pParse->db->mallocFailed==0 || pParse->nErr!=0 );
+  if( pParse->nErr==0 ){
+    const RenameToken *p;
+    u32 i = 1;
+    for(p=pParse->pRename; p; p=p->pNext){
+      if( p->p ){
+        assert( p->p!=pPtr );
+        i += *(u8*)(p->p) | 1;
+      }
+    }
+    assert( i>0 );
+  }
+}
+#else
+# define renameTokenCheckAll(x,y)
+#endif
+
+/*
+** Remember that the parser tree element pPtr was created using
+** the token pToken.
+**
+** In other words, construct a new RenameToken object and add it
+** to the list of RenameToken objects currently being built up
+** in pParse->pRename.
+**
+** The pPtr argument is returned so that this routine can be used
+** with tail recursion in tokenExpr() routine, for a small performance
+** improvement.
+*/
+SQLITE_PRIVATE const void *sqlite3RenameTokenMap(
+  Parse *pParse,
+  const void *pPtr,
+  const Token *pToken
+){
+  RenameToken *pNew;
+  assert( pPtr || pParse->db->mallocFailed );
+  renameTokenCheckAll(pParse, pPtr);
+  if( ALWAYS(pParse->eParseMode!=PARSE_MODE_UNMAP) ){
+    pNew = sqlite3DbMallocZero(pParse->db, sizeof(RenameToken));
+    if( pNew ){
+      pNew->p = pPtr;
+      pNew->t = *pToken;
+      pNew->pNext = pParse->pRename;
+      pParse->pRename = pNew;
+    }
+  }
+
+  return pPtr;
+}
+
+/*
+** It is assumed that there is already a RenameToken object associated
+** with parse tree element pFrom. This function remaps the associated token
+** to parse tree element pTo.
+*/
+SQLITE_PRIVATE void sqlite3RenameTokenRemap(Parse *pParse, const void *pTo, const void *pFrom){
+  RenameToken *p;
+  renameTokenCheckAll(pParse, pTo);
+  for(p=pParse->pRename; p; p=p->pNext){
+    if( p->p==pFrom ){
+      p->p = pTo;
+      break;
+    }
+  }
+}
+
+/*
+** Walker callback used by sqlite3RenameExprUnmap().
+*/
+static int renameUnmapExprCb(Walker *pWalker, Expr *pExpr){
+  Parse *pParse = pWalker->pParse;
+  sqlite3RenameTokenRemap(pParse, 0, (const void*)pExpr);
+  if( ExprUseYTab(pExpr) ){
+    sqlite3RenameTokenRemap(pParse, 0, (const void*)&pExpr->y.pTab);
+  }
+  return WRC_Continue;
+}
+
+/*
+** Iterate through the Select objects that are part of WITH clauses attached
+** to select statement pSelect.
+*/
+static void renameWalkWith(Walker *pWalker, Select *pSelect){
+  With *pWith = pSelect->pWith;
+  if( pWith ){
+    Parse *pParse = pWalker->pParse;
+    int i;
+    With *pCopy = 0;
+    assert( pWith->nCte>0 );
+    if( (pWith->a[0].pSelect->selFlags & SF_Expanded)==0 ){
+      /* Push a copy of the With object onto the with-stack. We use a copy
+      ** here as the original will be expanded and resolved (flags SF_Expanded
+      ** and SF_Resolved) below. And the parser code that uses the with-stack
+      ** fails if the Select objects on it have already been expanded and
+      ** resolved.  */
+      pCopy = sqlite3WithDup(pParse->db, pWith);
+      pCopy = sqlite3WithPush(pParse, pCopy, 1);
+    }
+    for(i=0; i<pWith->nCte; i++){
+      Select *p = pWith->a[i].pSelect;
+      NameContext sNC;
+      memset(&sNC, 0, sizeof(sNC));
+      sNC.pParse = pParse;
+      if( pCopy ) sqlite3SelectPrep(sNC.pParse, p, &sNC);
+      if( sNC.pParse->db->mallocFailed ) return;
+      sqlite3WalkSelect(pWalker, p);
+      sqlite3RenameExprlistUnmap(pParse, pWith->a[i].pCols);
+    }
+    if( pCopy && pParse->pWith==pCopy ){
+      pParse->pWith = pCopy->pOuter;
+    }
+  }
+}
+
+/*
+** Unmap all tokens in the IdList object passed as the second argument.
+*/
+static void unmapColumnIdlistNames(
+  Parse *pParse,
+  const IdList *pIdList
+){
+  int ii;
+  assert( pIdList!=0 );
+  for(ii=0; ii<pIdList->nId; ii++){
+    sqlite3RenameTokenRemap(pParse, 0, (const void*)pIdList->a[ii].zName);
+  }
+}
+
+/*
+** Walker callback used by sqlite3RenameExprUnmap().
+*/
+static int renameUnmapSelectCb(Walker *pWalker, Select *p){
+  Parse *pParse = pWalker->pParse;
+  int i;
+  if( pParse->nErr ) return WRC_Abort;
+  testcase( p->selFlags & SF_View );
+  testcase( p->selFlags & SF_CopyCte );
+  if( p->selFlags & (SF_View|SF_CopyCte) ){
+    return WRC_Prune;
+  }
+  if( ALWAYS(p->pEList) ){
+    ExprList *pList = p->pEList;
+    for(i=0; i<pList->nExpr; i++){
+      if( pList->a[i].zEName && pList->a[i].fg.eEName==ENAME_NAME ){
+        sqlite3RenameTokenRemap(pParse, 0, (void*)pList->a[i].zEName);
+      }
+    }
+  }
+  if( ALWAYS(p->pSrc) ){  /* Every Select as a SrcList, even if it is empty */
+    SrcList *pSrc = p->pSrc;
+    for(i=0; i<pSrc->nSrc; i++){
+      sqlite3RenameTokenRemap(pParse, 0, (void*)pSrc->a[i].zName);
+      if( pSrc->a[i].fg.isUsing==0 ){
+        sqlite3WalkExpr(pWalker, pSrc->a[i].u3.pOn);
+      }else{
+        unmapColumnIdlistNames(pParse, pSrc->a[i].u3.pUsing);
+      }
+    }
+  }
+
+  renameWalkWith(pWalker, p);
+  return WRC_Continue;
+}
+
+/*
+** Remove all nodes that are part of expression pExpr from the rename list.
+*/
+SQLITE_PRIVATE void sqlite3RenameExprUnmap(Parse *pParse, Expr *pExpr){
+  u8 eMode = pParse->eParseMode;
+  Walker sWalker;
+  memset(&sWalker, 0, sizeof(Walker));
+  sWalker.pParse = pParse;
+  sWalker.xExprCallback = renameUnmapExprCb;
+  sWalker.xSelectCallback = renameUnmapSelectCb;
+  pParse->eParseMode = PARSE_MODE_UNMAP;
+  sqlite3WalkExpr(&sWalker, pExpr);
+  pParse->eParseMode = eMode;
+}
+
+/*
+** Remove all nodes that are part of expression-list pEList from the
+** rename list.
+*/
+SQLITE_PRIVATE void sqlite3RenameExprlistUnmap(Parse *pParse, ExprList *pEList){
+  if( pEList ){
+    int i;
+    Walker sWalker;
+    memset(&sWalker, 0, sizeof(Walker));
+    sWalker.pParse = pParse;
+    sWalker.xExprCallback = renameUnmapExprCb;
+    sqlite3WalkExprList(&sWalker, pEList);
+    for(i=0; i<pEList->nExpr; i++){
+      if( ALWAYS(pEList->a[i].fg.eEName==ENAME_NAME) ){
+        sqlite3RenameTokenRemap(pParse, 0, (void*)pEList->a[i].zEName);
+      }
+    }
+  }
+}
+
+/*
+** Free the list of RenameToken objects given in the second argument
+*/
+static void renameTokenFree(sqlite3 *db, RenameToken *pToken){
+  RenameToken *pNext;
+  RenameToken *p;
+  for(p=pToken; p; p=pNext){
+    pNext = p->pNext;
+    sqlite3DbFree(db, p);
+  }
+}
+
+/*
+** Search the Parse object passed as the first argument for a RenameToken
+** object associated with parse tree element pPtr. If found, return a pointer
+** to it. Otherwise, return NULL.
+**
+** If the second argument passed to this function is not NULL and a matching
+** RenameToken object is found, remove it from the Parse object and add it to
+** the list maintained by the RenameCtx object.
+*/
+static RenameToken *renameTokenFind(
+  Parse *pParse,
+  struct RenameCtx *pCtx,
+  const void *pPtr
+){
+  RenameToken **pp;
+  if( NEVER(pPtr==0) ){
+    return 0;
+  }
+  for(pp=&pParse->pRename; (*pp); pp=&(*pp)->pNext){
+    if( (*pp)->p==pPtr ){
+      RenameToken *pToken = *pp;
+      if( pCtx ){
+        *pp = pToken->pNext;
+        pToken->pNext = pCtx->pList;
+        pCtx->pList = pToken;
+        pCtx->nList++;
+      }
+      return pToken;
+    }
+  }
+  return 0;
+}
+
+/*
+** This is a Walker select callback. It does nothing. It is only required
+** because without a dummy callback, sqlite3WalkExpr() and similar do not
+** descend into sub-select statements.
+*/
+static int renameColumnSelectCb(Walker *pWalker, Select *p){
+  if( p->selFlags & (SF_View|SF_CopyCte) ){
+    testcase( p->selFlags & SF_View );
+    testcase( p->selFlags & SF_CopyCte );
+    return WRC_Prune;
+  }
+  renameWalkWith(pWalker, p);
+  return WRC_Continue;
+}
+
+/*
+** This is a Walker expression callback.
+**
+** For every TK_COLUMN node in the expression tree, search to see
+** if the column being references is the column being renamed by an
+** ALTER TABLE statement.  If it is, then attach its associated
+** RenameToken object to the list of RenameToken objects being
+** constructed in RenameCtx object at pWalker->u.pRename.
+*/
+static int renameColumnExprCb(Walker *pWalker, Expr *pExpr){
+  RenameCtx *p = pWalker->u.pRename;
+  if( pExpr->op==TK_TRIGGER
+   && pExpr->iColumn==p->iCol
+   && pWalker->pParse->pTriggerTab==p->pTab
+  ){
+    renameTokenFind(pWalker->pParse, p, (void*)pExpr);
+  }else if( pExpr->op==TK_COLUMN
+   && pExpr->iColumn==p->iCol
+   && ALWAYS(ExprUseYTab(pExpr))
+   && p->pTab==pExpr->y.pTab
+  ){
+    renameTokenFind(pWalker->pParse, p, (void*)pExpr);
+  }
+  return WRC_Continue;
+}
+
+/*
+** The RenameCtx contains a list of tokens that reference a column that
+** is being renamed by an ALTER TABLE statement.  Return the "last"
+** RenameToken in the RenameCtx and remove that RenameToken from the
+** RenameContext.  "Last" means the last RenameToken encountered when
+** the input SQL is parsed from left to right.  Repeated calls to this routine
+** return all column name tokens in the order that they are encountered
+** in the SQL statement.
+*/
+static RenameToken *renameColumnTokenNext(RenameCtx *pCtx){
+  RenameToken *pBest = pCtx->pList;
+  RenameToken *pToken;
+  RenameToken **pp;
+
+  for(pToken=pBest->pNext; pToken; pToken=pToken->pNext){
+    if( pToken->t.z>pBest->t.z ) pBest = pToken;
+  }
+  for(pp=&pCtx->pList; *pp!=pBest; pp=&(*pp)->pNext);
+  *pp = pBest->pNext;
+
+  return pBest;
+}
+
+/*
+** An error occurred while parsing or otherwise processing a database
+** object (either pParse->pNewTable, pNewIndex or pNewTrigger) as part of an
+** ALTER TABLE RENAME COLUMN program. The error message emitted by the
+** sub-routine is currently stored in pParse->zErrMsg. This function
+** adds context to the error message and then stores it in pCtx.
+*/
+static void renameColumnParseError(
+  sqlite3_context *pCtx,
+  const char *zWhen,
+  sqlite3_value *pType,
+  sqlite3_value *pObject,
+  Parse *pParse
+){
+  const char *zT = (const char*)sqlite3_value_text(pType);
+  const char *zN = (const char*)sqlite3_value_text(pObject);
+  char *zErr;
+
+  zErr = sqlite3MPrintf(pParse->db, "error in %s %s%s%s: %s",
+      zT, zN, (zWhen[0] ? " " : ""), zWhen,
+      pParse->zErrMsg
+  );
+  sqlite3_result_error(pCtx, zErr, -1);
+  sqlite3DbFree(pParse->db, zErr);
+}
+
+/*
+** For each name in the the expression-list pEList (i.e. each
+** pEList->a[i].zName) that matches the string in zOld, extract the
+** corresponding rename-token from Parse object pParse and add it
+** to the RenameCtx pCtx.
+*/
+static void renameColumnElistNames(
+  Parse *pParse,
+  RenameCtx *pCtx,
+  const ExprList *pEList,
+  const char *zOld
+){
+  if( pEList ){
+    int i;
+    for(i=0; i<pEList->nExpr; i++){
+      const char *zName = pEList->a[i].zEName;
+      if( ALWAYS(pEList->a[i].fg.eEName==ENAME_NAME)
+       && ALWAYS(zName!=0)
+       && 0==sqlite3_stricmp(zName, zOld)
+      ){
+        renameTokenFind(pParse, pCtx, (const void*)zName);
+      }
+    }
+  }
+}
+
+/*
+** For each name in the the id-list pIdList (i.e. each pIdList->a[i].zName)
+** that matches the string in zOld, extract the corresponding rename-token
+** from Parse object pParse and add it to the RenameCtx pCtx.
+*/
+static void renameColumnIdlistNames(
+  Parse *pParse,
+  RenameCtx *pCtx,
+  const IdList *pIdList,
+  const char *zOld
+){
+  if( pIdList ){
+    int i;
+    for(i=0; i<pIdList->nId; i++){
+      const char *zName = pIdList->a[i].zName;
+      if( 0==sqlite3_stricmp(zName, zOld) ){
+        renameTokenFind(pParse, pCtx, (const void*)zName);
+      }
+    }
+  }
+}
+
+
+/*
+** Parse the SQL statement zSql using Parse object (*p). The Parse object
+** is initialized by this function before it is used.
+*/
+static int renameParseSql(
+  Parse *p,                       /* Memory to use for Parse object */
+  const char *zDb,                /* Name of schema SQL belongs to */
+  sqlite3 *db,                    /* Database handle */
+  const char *zSql,               /* SQL to parse */
+  int bTemp                       /* True if SQL is from temp schema */
+){
+  int rc;
+
+  sqlite3ParseObjectInit(p, db);
+  if( zSql==0 ){
+    return SQLITE_NOMEM;
+  }
+  if( sqlite3StrNICmp(zSql,"CREATE ",7)!=0 ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  db->init.iDb = bTemp ? 1 : sqlite3FindDbName(db, zDb);
+  p->eParseMode = PARSE_MODE_RENAME;
+  p->db = db;
+  p->nQueryLoop = 1;
+  rc = sqlite3RunParser(p, zSql);
+  if( db->mallocFailed ) rc = SQLITE_NOMEM;
+  if( rc==SQLITE_OK
+   && NEVER(p->pNewTable==0 && p->pNewIndex==0 && p->pNewTrigger==0)
+  ){
+    rc = SQLITE_CORRUPT_BKPT;
+  }
+
+#ifdef SQLITE_DEBUG
+  /* Ensure that all mappings in the Parse.pRename list really do map to
+  ** a part of the input string.  */
+  if( rc==SQLITE_OK ){
+    int nSql = sqlite3Strlen30(zSql);
+    RenameToken *pToken;
+    for(pToken=p->pRename; pToken; pToken=pToken->pNext){
+      assert( pToken->t.z>=zSql && &pToken->t.z[pToken->t.n]<=&zSql[nSql] );
+    }
+  }
+#endif
+
+  db->init.iDb = 0;
+  return rc;
+}
+
+/*
+** This function edits SQL statement zSql, replacing each token identified
+** by the linked list pRename with the text of zNew. If argument bQuote is
+** true, then zNew is always quoted first. If no error occurs, the result
+** is loaded into context object pCtx as the result.
+**
+** Or, if an error occurs (i.e. an OOM condition), an error is left in
+** pCtx and an SQLite error code returned.
+*/
+static int renameEditSql(
+  sqlite3_context *pCtx,          /* Return result here */
+  RenameCtx *pRename,             /* Rename context */
+  const char *zSql,               /* SQL statement to edit */
+  const char *zNew,               /* New token text */
+  int bQuote                      /* True to always quote token */
+){
+  i64 nNew = sqlite3Strlen30(zNew);
+  i64 nSql = sqlite3Strlen30(zSql);
+  sqlite3 *db = sqlite3_context_db_handle(pCtx);
+  int rc = SQLITE_OK;
+  char *zQuot = 0;
+  char *zOut;
+  i64 nQuot = 0;
+  char *zBuf1 = 0;
+  char *zBuf2 = 0;
+
+  if( zNew ){
+    /* Set zQuot to point to a buffer containing a quoted copy of the
+    ** identifier zNew. If the corresponding identifier in the original
+    ** ALTER TABLE statement was quoted (bQuote==1), then set zNew to
+    ** point to zQuot so that all substitutions are made using the
+    ** quoted version of the new column name.  */
+    zQuot = sqlite3MPrintf(db, "\"%w\" ", zNew);
+    if( zQuot==0 ){
+      return SQLITE_NOMEM;
+    }else{
+      nQuot = sqlite3Strlen30(zQuot)-1;
+    }
+
+    assert( nQuot>=nNew );
+    zOut = sqlite3DbMallocZero(db, nSql + pRename->nList*nQuot + 1);
+  }else{
+    zOut = (char*)sqlite3DbMallocZero(db, (nSql*2+1) * 3);
+    if( zOut ){
+      zBuf1 = &zOut[nSql*2+1];
+      zBuf2 = &zOut[nSql*4+2];
+    }
+  }
+
+  /* At this point pRename->pList contains a list of RenameToken objects
+  ** corresponding to all tokens in the input SQL that must be replaced
+  ** with the new column name, or with single-quoted versions of themselves.
+  ** All that remains is to construct and return the edited SQL string. */
+  if( zOut ){
+    int nOut = nSql;
+    memcpy(zOut, zSql, nSql);
+    while( pRename->pList ){
+      int iOff;                   /* Offset of token to replace in zOut */
+      u32 nReplace;
+      const char *zReplace;
+      RenameToken *pBest = renameColumnTokenNext(pRename);
+
+      if( zNew ){
+        if( bQuote==0 && sqlite3IsIdChar(*pBest->t.z) ){
+          nReplace = nNew;
+          zReplace = zNew;
+        }else{
+          nReplace = nQuot;
+          zReplace = zQuot;
+          if( pBest->t.z[pBest->t.n]=='"' ) nReplace++;
+        }
+      }else{
+        /* Dequote the double-quoted token. Then requote it again, this time
+        ** using single quotes. If the character immediately following the
+        ** original token within the input SQL was a single quote ('), then
+        ** add another space after the new, single-quoted version of the
+        ** token. This is so that (SELECT "string"'alias') maps to
+        ** (SELECT 'string' 'alias'), and not (SELECT 'string''alias').  */
+        memcpy(zBuf1, pBest->t.z, pBest->t.n);
+        zBuf1[pBest->t.n] = 0;
+        sqlite3Dequote(zBuf1);
+        sqlite3_snprintf(nSql*2, zBuf2, "%Q%s", zBuf1,
+            pBest->t.z[pBest->t.n]=='\'' ? " " : ""
+        );
+        zReplace = zBuf2;
+        nReplace = sqlite3Strlen30(zReplace);
+      }
+
+      iOff = pBest->t.z - zSql;
+      if( pBest->t.n!=nReplace ){
+        memmove(&zOut[iOff + nReplace], &zOut[iOff + pBest->t.n],
+            nOut - (iOff + pBest->t.n)
+        );
+        nOut += nReplace - pBest->t.n;
+        zOut[nOut] = '\0';
+      }
+      memcpy(&zOut[iOff], zReplace, nReplace);
+      sqlite3DbFree(db, pBest);
+    }
+
+    sqlite3_result_text(pCtx, zOut, -1, SQLITE_TRANSIENT);
+    sqlite3DbFree(db, zOut);
+  }else{
+    rc = SQLITE_NOMEM;
+  }
+
+  sqlite3_free(zQuot);
+  return rc;
+}
+
+/*
+** Set all pEList->a[].fg.eEName fields in the expression-list to val.
+*/
+static void renameSetENames(ExprList *pEList, int val){
+  if( pEList ){
+    int i;
+    for(i=0; i<pEList->nExpr; i++){
+      assert( val==ENAME_NAME || pEList->a[i].fg.eEName==ENAME_NAME );
+      pEList->a[i].fg.eEName = val;
+    }
+  }
+}
+
+/*
+** Resolve all symbols in the trigger at pParse->pNewTrigger, assuming
+** it was read from the schema of database zDb. Return SQLITE_OK if
+** successful. Otherwise, return an SQLite error code and leave an error
+** message in the Parse object.
+*/
+static int renameResolveTrigger(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  Trigger *pNew = pParse->pNewTrigger;
+  TriggerStep *pStep;
+  NameContext sNC;
+  int rc = SQLITE_OK;
+
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  assert( pNew->pTabSchema );
+  pParse->pTriggerTab = sqlite3FindTable(db, pNew->table,
+      db->aDb[sqlite3SchemaToIndex(db, pNew->pTabSchema)].zDbSName
+  );
+  pParse->eTriggerOp = pNew->op;
+  /* ALWAYS() because if the table of the trigger does not exist, the
+  ** error would have been hit before this point */
+  if( ALWAYS(pParse->pTriggerTab) ){
+    rc = sqlite3ViewGetColumnNames(pParse, pParse->pTriggerTab)!=0;
+  }
+
+  /* Resolve symbols in WHEN clause */
+  if( rc==SQLITE_OK && pNew->pWhen ){
+    rc = sqlite3ResolveExprNames(&sNC, pNew->pWhen);
+  }
+
+  for(pStep=pNew->step_list; rc==SQLITE_OK && pStep; pStep=pStep->pNext){
+    if( pStep->pSelect ){
+      sqlite3SelectPrep(pParse, pStep->pSelect, &sNC);
+      if( pParse->nErr ) rc = pParse->rc;
+    }
+    if( rc==SQLITE_OK && pStep->zTarget ){
+      SrcList *pSrc = sqlite3TriggerStepSrc(pParse, pStep);
+      if( pSrc ){
+        Select *pSel = sqlite3SelectNew(
+            pParse, pStep->pExprList, pSrc, 0, 0, 0, 0, 0, 0
+        );
+        if( pSel==0 ){
+          pStep->pExprList = 0;
+          pSrc = 0;
+          rc = SQLITE_NOMEM;
+        }else{
+          /* pStep->pExprList contains an expression-list used for an UPDATE
+          ** statement. So the a[].zEName values are the RHS of the
+          ** "<col> = <expr>" clauses of the UPDATE statement. So, before
+          ** running SelectPrep(), change all the eEName values in
+          ** pStep->pExprList to ENAME_SPAN (from their current value of
+          ** ENAME_NAME). This is to prevent any ids in ON() clauses that are
+          ** part of pSrc from being incorrectly resolved against the
+          ** a[].zEName values as if they were column aliases.  */
+          renameSetENames(pStep->pExprList, ENAME_SPAN);
+          sqlite3SelectPrep(pParse, pSel, 0);
+          renameSetENames(pStep->pExprList, ENAME_NAME);
+          rc = pParse->nErr ? SQLITE_ERROR : SQLITE_OK;
+          assert( pStep->pExprList==0 || pStep->pExprList==pSel->pEList );
+          assert( pSrc==pSel->pSrc );
+          if( pStep->pExprList ) pSel->pEList = 0;
+          pSel->pSrc = 0;
+          sqlite3SelectDelete(db, pSel);
+        }
+        if( pStep->pFrom ){
+          int i;
+          for(i=0; i<pStep->pFrom->nSrc && rc==SQLITE_OK; i++){
+            SrcItem *p = &pStep->pFrom->a[i];
+            if( p->fg.isSubquery ){
+              assert( p->u4.pSubq!=0 );
+              sqlite3SelectPrep(pParse, p->u4.pSubq->pSelect, 0);
+            }
+          }
+        }
+
+        if(  db->mallocFailed ){
+          rc = SQLITE_NOMEM;
+        }
+        sNC.pSrcList = pSrc;
+        if( rc==SQLITE_OK && pStep->pWhere ){
+          rc = sqlite3ResolveExprNames(&sNC, pStep->pWhere);
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3ResolveExprListNames(&sNC, pStep->pExprList);
+        }
+        assert( !pStep->pUpsert || (!pStep->pWhere && !pStep->pExprList) );
+        if( pStep->pUpsert && rc==SQLITE_OK ){
+          Upsert *pUpsert = pStep->pUpsert;
+          pUpsert->pUpsertSrc = pSrc;
+          sNC.uNC.pUpsert = pUpsert;
+          sNC.ncFlags = NC_UUpsert;
+          rc = sqlite3ResolveExprListNames(&sNC, pUpsert->pUpsertTarget);
+          if( rc==SQLITE_OK ){
+            ExprList *pUpsertSet = pUpsert->pUpsertSet;
+            rc = sqlite3ResolveExprListNames(&sNC, pUpsertSet);
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3ResolveExprNames(&sNC, pUpsert->pUpsertWhere);
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3ResolveExprNames(&sNC, pUpsert->pUpsertTargetWhere);
+          }
+          sNC.ncFlags = 0;
+        }
+        sNC.pSrcList = 0;
+        sqlite3SrcListDelete(db, pSrc);
+      }else{
+        rc = SQLITE_NOMEM;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Invoke sqlite3WalkExpr() or sqlite3WalkSelect() on all Select or Expr
+** objects that are part of the trigger passed as the second argument.
+*/
+static void renameWalkTrigger(Walker *pWalker, Trigger *pTrigger){
+  TriggerStep *pStep;
+
+  /* Find tokens to edit in WHEN clause */
+  sqlite3WalkExpr(pWalker, pTrigger->pWhen);
+
+  /* Find tokens to edit in trigger steps */
+  for(pStep=pTrigger->step_list; pStep; pStep=pStep->pNext){
+    sqlite3WalkSelect(pWalker, pStep->pSelect);
+    sqlite3WalkExpr(pWalker, pStep->pWhere);
+    sqlite3WalkExprList(pWalker, pStep->pExprList);
+    if( pStep->pUpsert ){
+      Upsert *pUpsert = pStep->pUpsert;
+      sqlite3WalkExprList(pWalker, pUpsert->pUpsertTarget);
+      sqlite3WalkExprList(pWalker, pUpsert->pUpsertSet);
+      sqlite3WalkExpr(pWalker, pUpsert->pUpsertWhere);
+      sqlite3WalkExpr(pWalker, pUpsert->pUpsertTargetWhere);
+    }
+    if( pStep->pFrom ){
+      int i;
+      SrcList *pFrom = pStep->pFrom;
+      for(i=0; i<pFrom->nSrc; i++){
+        if( pFrom->a[i].fg.isSubquery ){
+          assert( pFrom->a[i].u4.pSubq!=0 );
+          sqlite3WalkSelect(pWalker, pFrom->a[i].u4.pSubq->pSelect);
+        }
+      }
+    }
+  }
+}
+
+/*
+** Free the contents of Parse object (*pParse). Do not free the memory
+** occupied by the Parse object itself.
+*/
+static void renameParseCleanup(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  Index *pIdx;
+  if( pParse->pVdbe ){
+    sqlite3VdbeFinalize(pParse->pVdbe);
+  }
+  sqlite3DeleteTable(db, pParse->pNewTable);
+  while( (pIdx = pParse->pNewIndex)!=0 ){
+    pParse->pNewIndex = pIdx->pNext;
+    sqlite3FreeIndex(db, pIdx);
+  }
+  sqlite3DeleteTrigger(db, pParse->pNewTrigger);
+  sqlite3DbFree(db, pParse->zErrMsg);
+  renameTokenFree(db, pParse->pRename);
+  sqlite3ParseObjectReset(pParse);
+}
+
+/*
+** SQL function:
+**
+**     sqlite_rename_column(SQL,TYPE,OBJ,DB,TABLE,COL,NEWNAME,QUOTE,TEMP)
+**
+**   0. zSql:     SQL statement to rewrite
+**   1. type:     Type of object ("table", "view" etc.)
+**   2. object:   Name of object
+**   3. Database: Database name (e.g. "main")
+**   4. Table:    Table name
+**   5. iCol:     Index of column to rename
+**   6. zNew:     New column name
+**   7. bQuote:   Non-zero if the new column name should be quoted.
+**   8. bTemp:    True if zSql comes from temp schema
+**
+** Do a column rename operation on the CREATE statement given in zSql.
+** The iCol-th column (left-most is 0) of table zTable is renamed from zCol
+** into zNew.  The name should be quoted if bQuote is true.
+**
+** This function is used internally by the ALTER TABLE RENAME COLUMN command.
+** It is only accessible to SQL created using sqlite3NestedParse().  It is
+** not reachable from ordinary SQL passed into sqlite3_prepare() unless the
+** SQLITE_TESTCTRL_INTERNAL_FUNCTIONS test setting is enabled.
+*/
+static void renameColumnFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  RenameCtx sCtx;
+  const char *zSql = (const char*)sqlite3_value_text(argv[0]);
+  const char *zDb = (const char*)sqlite3_value_text(argv[3]);
+  const char *zTable = (const char*)sqlite3_value_text(argv[4]);
+  int iCol = sqlite3_value_int(argv[5]);
+  const char *zNew = (const char*)sqlite3_value_text(argv[6]);
+  int bQuote = sqlite3_value_int(argv[7]);
+  int bTemp = sqlite3_value_int(argv[8]);
+  const char *zOld;
+  int rc;
+  Parse sParse;
+  Walker sWalker;
+  Index *pIdx;
+  int i;
+  Table *pTab;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth = db->xAuth;
+#endif
+
+  UNUSED_PARAMETER(NotUsed);
+  if( zSql==0 ) return;
+  if( zTable==0 ) return;
+  if( zNew==0 ) return;
+  if( iCol<0 ) return;
+  sqlite3BtreeEnterAll(db);
+  pTab = sqlite3FindTable(db, zTable, zDb);
+  if( pTab==0 || iCol>=pTab->nCol ){
+    sqlite3BtreeLeaveAll(db);
+    return;
+  }
+  zOld = pTab->aCol[iCol].zCnName;
+  memset(&sCtx, 0, sizeof(sCtx));
+  sCtx.iCol = ((iCol==pTab->iPKey) ? -1 : iCol);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = 0;
+#endif
+  rc = renameParseSql(&sParse, zDb, db, zSql, bTemp);
+
+  /* Find tokens that need to be replaced. */
+  memset(&sWalker, 0, sizeof(Walker));
+  sWalker.pParse = &sParse;
+  sWalker.xExprCallback = renameColumnExprCb;
+  sWalker.xSelectCallback = renameColumnSelectCb;
+  sWalker.u.pRename = &sCtx;
+
+  sCtx.pTab = pTab;
+  if( rc!=SQLITE_OK ) goto renameColumnFunc_done;
+  if( sParse.pNewTable ){
+    if( IsView(sParse.pNewTable) ){
+      Select *pSelect = sParse.pNewTable->u.view.pSelect;
+      pSelect->selFlags &= ~SF_View;
+      sParse.rc = SQLITE_OK;
+      sqlite3SelectPrep(&sParse, pSelect, 0);
+      rc = (db->mallocFailed ? SQLITE_NOMEM : sParse.rc);
+      if( rc==SQLITE_OK ){
+        sqlite3WalkSelect(&sWalker, pSelect);
+      }
+      if( rc!=SQLITE_OK ) goto renameColumnFunc_done;
+    }else if( IsOrdinaryTable(sParse.pNewTable) ){
+      /* A regular table */
+      int bFKOnly = sqlite3_stricmp(zTable, sParse.pNewTable->zName);
+      FKey *pFKey;
+      sCtx.pTab = sParse.pNewTable;
+      if( bFKOnly==0 ){
+        if( iCol<sParse.pNewTable->nCol ){
+          renameTokenFind(
+              &sParse, &sCtx, (void*)sParse.pNewTable->aCol[iCol].zCnName
+          );
+        }
+        if( sCtx.iCol<0 ){
+          renameTokenFind(&sParse, &sCtx, (void*)&sParse.pNewTable->iPKey);
+        }
+        sqlite3WalkExprList(&sWalker, sParse.pNewTable->pCheck);
+        for(pIdx=sParse.pNewTable->pIndex; pIdx; pIdx=pIdx->pNext){
+          sqlite3WalkExprList(&sWalker, pIdx->aColExpr);
+        }
+        for(pIdx=sParse.pNewIndex; pIdx; pIdx=pIdx->pNext){
+          sqlite3WalkExprList(&sWalker, pIdx->aColExpr);
+        }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+        for(i=0; i<sParse.pNewTable->nCol; i++){
+          Expr *pExpr = sqlite3ColumnExpr(sParse.pNewTable,
+                                                  &sParse.pNewTable->aCol[i]);
+          sqlite3WalkExpr(&sWalker, pExpr);
+        }
+#endif
+      }
+
+      assert( IsOrdinaryTable(sParse.pNewTable) );
+      for(pFKey=sParse.pNewTable->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+        for(i=0; i<pFKey->nCol; i++){
+          if( bFKOnly==0 && pFKey->aCol[i].iFrom==iCol ){
+            renameTokenFind(&sParse, &sCtx, (void*)&pFKey->aCol[i]);
+          }
+          if( 0==sqlite3_stricmp(pFKey->zTo, zTable)
+           && 0==sqlite3_stricmp(pFKey->aCol[i].zCol, zOld)
+          ){
+            renameTokenFind(&sParse, &sCtx, (void*)pFKey->aCol[i].zCol);
+          }
+        }
+      }
+    }
+  }else if( sParse.pNewIndex ){
+    sqlite3WalkExprList(&sWalker, sParse.pNewIndex->aColExpr);
+    sqlite3WalkExpr(&sWalker, sParse.pNewIndex->pPartIdxWhere);
+  }else{
+    /* A trigger */
+    TriggerStep *pStep;
+    rc = renameResolveTrigger(&sParse);
+    if( rc!=SQLITE_OK ) goto renameColumnFunc_done;
+
+    for(pStep=sParse.pNewTrigger->step_list; pStep; pStep=pStep->pNext){
+      if( pStep->zTarget ){
+        Table *pTarget = sqlite3LocateTable(&sParse, 0, pStep->zTarget, zDb);
+        if( pTarget==pTab ){
+          if( pStep->pUpsert ){
+            ExprList *pUpsertSet = pStep->pUpsert->pUpsertSet;
+            renameColumnElistNames(&sParse, &sCtx, pUpsertSet, zOld);
+          }
+          renameColumnIdlistNames(&sParse, &sCtx, pStep->pIdList, zOld);
+          renameColumnElistNames(&sParse, &sCtx, pStep->pExprList, zOld);
+        }
+      }
+    }
+
+
+    /* Find tokens to edit in UPDATE OF clause */
+    if( sParse.pTriggerTab==pTab ){
+      renameColumnIdlistNames(&sParse, &sCtx,sParse.pNewTrigger->pColumns,zOld);
+    }
+
+    /* Find tokens to edit in various expressions and selects */
+    renameWalkTrigger(&sWalker, sParse.pNewTrigger);
+  }
+
+  assert( rc==SQLITE_OK );
+  rc = renameEditSql(context, &sCtx, zSql, zNew, bQuote);
+
+renameColumnFunc_done:
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_ERROR && sqlite3WritableSchema(db) ){
+      sqlite3_result_value(context, argv[0]);
+    }else if( sParse.zErrMsg ){
+      renameColumnParseError(context, "", argv[1], argv[2], &sParse);
+    }else{
+      sqlite3_result_error_code(context, rc);
+    }
+  }
+
+  renameParseCleanup(&sParse);
+  renameTokenFree(db, sCtx.pList);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+  sqlite3BtreeLeaveAll(db);
+}
+
+/*
+** Walker expression callback used by "RENAME TABLE".
+*/
+static int renameTableExprCb(Walker *pWalker, Expr *pExpr){
+  RenameCtx *p = pWalker->u.pRename;
+  if( pExpr->op==TK_COLUMN
+   && ALWAYS(ExprUseYTab(pExpr))
+   && p->pTab==pExpr->y.pTab
+  ){
+    renameTokenFind(pWalker->pParse, p, (void*)&pExpr->y.pTab);
+  }
+  return WRC_Continue;
+}
+
+/*
+** Walker select callback used by "RENAME TABLE".
+*/
+static int renameTableSelectCb(Walker *pWalker, Select *pSelect){
+  int i;
+  RenameCtx *p = pWalker->u.pRename;
+  SrcList *pSrc = pSelect->pSrc;
+  if( pSelect->selFlags & (SF_View|SF_CopyCte) ){
+    testcase( pSelect->selFlags & SF_View );
+    testcase( pSelect->selFlags & SF_CopyCte );
+    return WRC_Prune;
+  }
+  if( NEVER(pSrc==0) ){
+    assert( pWalker->pParse->db->mallocFailed );
+    return WRC_Abort;
+  }
+  for(i=0; i<pSrc->nSrc; i++){
+    SrcItem *pItem = &pSrc->a[i];
+    if( pItem->pSTab==p->pTab ){
+      renameTokenFind(pWalker->pParse, p, pItem->zName);
+    }
+  }
+  renameWalkWith(pWalker, pSelect);
+
+  return WRC_Continue;
+}
+
+
+/*
+** This C function implements an SQL user function that is used by SQL code
+** generated by the ALTER TABLE ... RENAME command to modify the definition
+** of any foreign key constraints that use the table being renamed as the
+** parent table. It is passed three arguments:
+**
+**   0: The database containing the table being renamed.
+**   1. type:     Type of object ("table", "view" etc.)
+**   2. object:   Name of object
+**   3: The complete text of the schema statement being modified,
+**   4: The old name of the table being renamed, and
+**   5: The new name of the table being renamed.
+**   6: True if the schema statement comes from the temp db.
+**
+** It returns the new schema statement. For example:
+**
+** sqlite_rename_table('main', 'CREATE TABLE t1(a REFERENCES t2)','t2','t3',0)
+**       -> 'CREATE TABLE t1(a REFERENCES t3)'
+*/
+static void renameTableFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  const char *zDb = (const char*)sqlite3_value_text(argv[0]);
+  const char *zInput = (const char*)sqlite3_value_text(argv[3]);
+  const char *zOld = (const char*)sqlite3_value_text(argv[4]);
+  const char *zNew = (const char*)sqlite3_value_text(argv[5]);
+  int bTemp = sqlite3_value_int(argv[6]);
+  UNUSED_PARAMETER(NotUsed);
+
+  if( zInput && zOld && zNew ){
+    Parse sParse;
+    int rc;
+    int bQuote = 1;
+    RenameCtx sCtx;
+    Walker sWalker;
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    sqlite3_xauth xAuth = db->xAuth;
+    db->xAuth = 0;
+#endif
+
+    sqlite3BtreeEnterAll(db);
+
+    memset(&sCtx, 0, sizeof(RenameCtx));
+    sCtx.pTab = sqlite3FindTable(db, zOld, zDb);
+    memset(&sWalker, 0, sizeof(Walker));
+    sWalker.pParse = &sParse;
+    sWalker.xExprCallback = renameTableExprCb;
+    sWalker.xSelectCallback = renameTableSelectCb;
+    sWalker.u.pRename = &sCtx;
+
+    rc = renameParseSql(&sParse, zDb, db, zInput, bTemp);
+
+    if( rc==SQLITE_OK ){
+      int isLegacy = (db->flags & SQLITE_LegacyAlter);
+      if( sParse.pNewTable ){
+        Table *pTab = sParse.pNewTable;
+
+        if( IsView(pTab) ){
+          if( isLegacy==0 ){
+            Select *pSelect = pTab->u.view.pSelect;
+            NameContext sNC;
+            memset(&sNC, 0, sizeof(sNC));
+            sNC.pParse = &sParse;
+
+            assert( pSelect->selFlags & SF_View );
+            pSelect->selFlags &= ~SF_View;
+            sqlite3SelectPrep(&sParse, pTab->u.view.pSelect, &sNC);
+            if( sParse.nErr ){
+              rc = sParse.rc;
+            }else{
+              sqlite3WalkSelect(&sWalker, pTab->u.view.pSelect);
+            }
+          }
+        }else{
+          /* Modify any FK definitions to point to the new table. */
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+          if( (isLegacy==0 || (db->flags & SQLITE_ForeignKeys))
+           && !IsVirtual(pTab)
+          ){
+            FKey *pFKey;
+            assert( IsOrdinaryTable(pTab) );
+            for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+              if( sqlite3_stricmp(pFKey->zTo, zOld)==0 ){
+                renameTokenFind(&sParse, &sCtx, (void*)pFKey->zTo);
+              }
+            }
+          }
+#endif
+
+          /* If this is the table being altered, fix any table refs in CHECK
+          ** expressions. Also update the name that appears right after the
+          ** "CREATE [VIRTUAL] TABLE" bit. */
+          if( sqlite3_stricmp(zOld, pTab->zName)==0 ){
+            sCtx.pTab = pTab;
+            if( isLegacy==0 ){
+              sqlite3WalkExprList(&sWalker, pTab->pCheck);
+            }
+            renameTokenFind(&sParse, &sCtx, pTab->zName);
+          }
+        }
+      }
+
+      else if( sParse.pNewIndex ){
+        renameTokenFind(&sParse, &sCtx, sParse.pNewIndex->zName);
+        if( isLegacy==0 ){
+          sqlite3WalkExpr(&sWalker, sParse.pNewIndex->pPartIdxWhere);
+        }
+      }
+
+#ifndef SQLITE_OMIT_TRIGGER
+      else{
+        Trigger *pTrigger = sParse.pNewTrigger;
+        TriggerStep *pStep;
+        if( 0==sqlite3_stricmp(sParse.pNewTrigger->table, zOld)
+            && sCtx.pTab->pSchema==pTrigger->pTabSchema
+          ){
+          renameTokenFind(&sParse, &sCtx, sParse.pNewTrigger->table);
+        }
+
+        if( isLegacy==0 ){
+          rc = renameResolveTrigger(&sParse);
+          if( rc==SQLITE_OK ){
+            renameWalkTrigger(&sWalker, pTrigger);
+            for(pStep=pTrigger->step_list; pStep; pStep=pStep->pNext){
+              if( pStep->zTarget && 0==sqlite3_stricmp(pStep->zTarget, zOld) ){
+                renameTokenFind(&sParse, &sCtx, pStep->zTarget);
+              }
+              if( pStep->pFrom ){
+                int i;
+                for(i=0; i<pStep->pFrom->nSrc; i++){
+                  SrcItem *pItem = &pStep->pFrom->a[i];
+                  if( 0==sqlite3_stricmp(pItem->zName, zOld) ){
+                    renameTokenFind(&sParse, &sCtx, pItem->zName);
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+#endif
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = renameEditSql(context, &sCtx, zInput, zNew, bQuote);
+    }
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_ERROR && sqlite3WritableSchema(db) ){
+        sqlite3_result_value(context, argv[3]);
+      }else if( sParse.zErrMsg ){
+        renameColumnParseError(context, "", argv[1], argv[2], &sParse);
+      }else{
+        sqlite3_result_error_code(context, rc);
+      }
+    }
+
+    renameParseCleanup(&sParse);
+    renameTokenFree(db, sCtx.pList);
+    sqlite3BtreeLeaveAll(db);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    db->xAuth = xAuth;
+#endif
+  }
+
+  return;
+}
+
+static int renameQuotefixExprCb(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_STRING && (pExpr->flags & EP_DblQuoted) ){
+    renameTokenFind(pWalker->pParse, pWalker->u.pRename, (const void*)pExpr);
+  }
+  return WRC_Continue;
+}
+
+/* SQL function: sqlite_rename_quotefix(DB,SQL)
+**
+** Rewrite the DDL statement "SQL" so that any string literals that use
+** double-quotes use single quotes instead.
+**
+** Two arguments must be passed:
+**
+**   0: Database name ("main", "temp" etc.).
+**   1: SQL statement to edit.
+**
+** The returned value is the modified SQL statement. For example, given
+** the database schema:
+**
+**   CREATE TABLE t1(a, b, c);
+**
+**   SELECT sqlite_rename_quotefix('main',
+**       'CREATE VIEW v1 AS SELECT "a", "string" FROM t1'
+**   );
+**
+** returns the string:
+**
+**   CREATE VIEW v1 AS SELECT "a", 'string' FROM t1
+**
+** If there is a error in the input SQL, then raise an error, except
+** if PRAGMA writable_schema=ON, then just return the input string
+** unmodified following an error.
+*/
+static void renameQuotefixFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  char const *zDb = (const char*)sqlite3_value_text(argv[0]);
+  char const *zInput = (const char*)sqlite3_value_text(argv[1]);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth = db->xAuth;
+  db->xAuth = 0;
+#endif
+
+  sqlite3BtreeEnterAll(db);
+
+  UNUSED_PARAMETER(NotUsed);
+  if( zDb && zInput ){
+    int rc;
+    Parse sParse;
+    rc = renameParseSql(&sParse, zDb, db, zInput, 0);
+
+    if( rc==SQLITE_OK ){
+      RenameCtx sCtx;
+      Walker sWalker;
+
+      /* Walker to find tokens that need to be replaced. */
+      memset(&sCtx, 0, sizeof(RenameCtx));
+      memset(&sWalker, 0, sizeof(Walker));
+      sWalker.pParse = &sParse;
+      sWalker.xExprCallback = renameQuotefixExprCb;
+      sWalker.xSelectCallback = renameColumnSelectCb;
+      sWalker.u.pRename = &sCtx;
+
+      if( sParse.pNewTable ){
+        if( IsView(sParse.pNewTable) ){
+          Select *pSelect = sParse.pNewTable->u.view.pSelect;
+          pSelect->selFlags &= ~SF_View;
+          sParse.rc = SQLITE_OK;
+          sqlite3SelectPrep(&sParse, pSelect, 0);
+          rc = (db->mallocFailed ? SQLITE_NOMEM : sParse.rc);
+          if( rc==SQLITE_OK ){
+            sqlite3WalkSelect(&sWalker, pSelect);
+          }
+        }else{
+          int i;
+          sqlite3WalkExprList(&sWalker, sParse.pNewTable->pCheck);
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+          for(i=0; i<sParse.pNewTable->nCol; i++){
+            sqlite3WalkExpr(&sWalker,
+               sqlite3ColumnExpr(sParse.pNewTable,
+                                         &sParse.pNewTable->aCol[i]));
+          }
+#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
+        }
+      }else if( sParse.pNewIndex ){
+        sqlite3WalkExprList(&sWalker, sParse.pNewIndex->aColExpr);
+        sqlite3WalkExpr(&sWalker, sParse.pNewIndex->pPartIdxWhere);
+      }else{
+#ifndef SQLITE_OMIT_TRIGGER
+        rc = renameResolveTrigger(&sParse);
+        if( rc==SQLITE_OK ){
+          renameWalkTrigger(&sWalker, sParse.pNewTrigger);
+        }
+#endif /* SQLITE_OMIT_TRIGGER */
+      }
+
+      if( rc==SQLITE_OK ){
+        rc = renameEditSql(context, &sCtx, zInput, 0, 0);
+      }
+      renameTokenFree(db, sCtx.pList);
+    }
+    if( rc!=SQLITE_OK ){
+      if( sqlite3WritableSchema(db) && rc==SQLITE_ERROR ){
+        sqlite3_result_value(context, argv[1]);
+      }else{
+        sqlite3_result_error_code(context, rc);
+      }
+    }
+    renameParseCleanup(&sParse);
+  }
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+
+  sqlite3BtreeLeaveAll(db);
+}
+
+/* Function:  sqlite_rename_test(DB,SQL,TYPE,NAME,ISTEMP,WHEN,DQS)
+**
+** An SQL user function that checks that there are no parse or symbol
+** resolution problems in a CREATE TRIGGER|TABLE|VIEW|INDEX statement.
+** After an ALTER TABLE .. RENAME operation is performed and the schema
+** reloaded, this function is called on each SQL statement in the schema
+** to ensure that it is still usable.
+**
+**   0: Database name ("main", "temp" etc.).
+**   1: SQL statement.
+**   2: Object type ("view", "table", "trigger" or "index").
+**   3: Object name.
+**   4: True if object is from temp schema.
+**   5: "when" part of error message.
+**   6: True to disable the DQS quirk when parsing SQL.
+**
+** The return value is computed as follows:
+**
+**   A. If an error is seen and not in PRAGMA writable_schema=ON mode,
+**      then raise the error.
+**   B. Else if a trigger is created and the the table that the trigger is
+**      attached to is in database zDb, then return 1.
+**   C. Otherwise return NULL.
+*/
+static void renameTableTest(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  char const *zDb = (const char*)sqlite3_value_text(argv[0]);
+  char const *zInput = (const char*)sqlite3_value_text(argv[1]);
+  int bTemp = sqlite3_value_int(argv[4]);
+  int isLegacy = (db->flags & SQLITE_LegacyAlter);
+  char const *zWhen = (const char*)sqlite3_value_text(argv[5]);
+  int bNoDQS = sqlite3_value_int(argv[6]);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth = db->xAuth;
+  db->xAuth = 0;
+#endif
+
+  UNUSED_PARAMETER(NotUsed);
+
+  if( zDb && zInput ){
+    int rc;
+    Parse sParse;
+    int flags = db->flags;
+    if( bNoDQS ) db->flags &= ~(SQLITE_DqsDML|SQLITE_DqsDDL);
+    rc = renameParseSql(&sParse, zDb, db, zInput, bTemp);
+    db->flags |= (flags & (SQLITE_DqsDML|SQLITE_DqsDDL));
+    if( rc==SQLITE_OK ){
+      if( isLegacy==0 && sParse.pNewTable && IsView(sParse.pNewTable) ){
+        NameContext sNC;
+        memset(&sNC, 0, sizeof(sNC));
+        sNC.pParse = &sParse;
+        sqlite3SelectPrep(&sParse, sParse.pNewTable->u.view.pSelect, &sNC);
+        if( sParse.nErr ) rc = sParse.rc;
+      }
+
+      else if( sParse.pNewTrigger ){
+        if( isLegacy==0 ){
+          rc = renameResolveTrigger(&sParse);
+        }
+        if( rc==SQLITE_OK ){
+          int i1 = sqlite3SchemaToIndex(db, sParse.pNewTrigger->pTabSchema);
+          int i2 = sqlite3FindDbName(db, zDb);
+          if( i1==i2 ){
+            /* Handle output case B */
+            sqlite3_result_int(context, 1);
+          }
+        }
+      }
+    }
+
+    if( rc!=SQLITE_OK && zWhen && !sqlite3WritableSchema(db) ){
+      /* Output case A */
+      renameColumnParseError(context, zWhen, argv[2], argv[3],&sParse);
+    }
+    renameParseCleanup(&sParse);
+  }
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+}
+
+/*
+** The implementation of internal UDF sqlite_drop_column().
+**
+** Arguments:
+**
+**  argv[0]: An integer - the index of the schema containing the table
+**  argv[1]: CREATE TABLE statement to modify.
+**  argv[2]: An integer - the index of the column to remove.
+**
+** The value returned is a string containing the CREATE TABLE statement
+** with column argv[2] removed.
+*/
+static void dropColumnFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  int iSchema = sqlite3_value_int(argv[0]);
+  const char *zSql = (const char*)sqlite3_value_text(argv[1]);
+  int iCol = sqlite3_value_int(argv[2]);
+  const char *zDb = db->aDb[iSchema].zDbSName;
+  int rc;
+  Parse sParse;
+  RenameToken *pCol;
+  Table *pTab;
+  const char *zEnd;
+  char *zNew = 0;
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth = db->xAuth;
+  db->xAuth = 0;
+#endif
+
+  UNUSED_PARAMETER(NotUsed);
+  rc = renameParseSql(&sParse, zDb, db, zSql, iSchema==1);
+  if( rc!=SQLITE_OK ) goto drop_column_done;
+  pTab = sParse.pNewTable;
+  if( pTab==0 || pTab->nCol==1 || iCol>=pTab->nCol ){
+    /* This can happen if the sqlite_schema table is corrupt */
+    rc = SQLITE_CORRUPT_BKPT;
+    goto drop_column_done;
+  }
+
+  pCol = renameTokenFind(&sParse, 0, (void*)pTab->aCol[iCol].zCnName);
+  if( iCol<pTab->nCol-1 ){
+    RenameToken *pEnd;
+    pEnd = renameTokenFind(&sParse, 0, (void*)pTab->aCol[iCol+1].zCnName);
+    zEnd = (const char*)pEnd->t.z;
+  }else{
+    assert( IsOrdinaryTable(pTab) );
+    zEnd = (const char*)&zSql[pTab->u.tab.addColOffset];
+    while( ALWAYS(pCol->t.z[0]!=0) && pCol->t.z[0]!=',' ) pCol->t.z--;
+  }
+
+  zNew = sqlite3MPrintf(db, "%.*s%s", pCol->t.z-zSql, zSql, zEnd);
+  sqlite3_result_text(context, zNew, -1, SQLITE_TRANSIENT);
+  sqlite3_free(zNew);
+
+drop_column_done:
+  renameParseCleanup(&sParse);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  db->xAuth = xAuth;
+#endif
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(context, rc);
+  }
+}
+
+/*
+** This function is called by the parser upon parsing an
+**
+**     ALTER TABLE pSrc DROP COLUMN pName
+**
+** statement. Argument pSrc contains the possibly qualified name of the
+** table being edited, and token pName the name of the column to drop.
+*/
+SQLITE_PRIVATE void sqlite3AlterDropColumn(Parse *pParse, SrcList *pSrc, const Token *pName){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  Table *pTab;                    /* Table to modify */
+  int iDb;                        /* Index of db containing pTab in aDb[] */
+  const char *zDb;                /* Database containing pTab ("main" etc.) */
+  char *zCol = 0;                 /* Name of column to drop */
+  int iCol;                       /* Index of column zCol in pTab->aCol[] */
+
+  /* Look up the table being altered. */
+  assert( pParse->pNewTable==0 );
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  if( NEVER(db->mallocFailed) ) goto exit_drop_column;
+  pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
+  if( !pTab ) goto exit_drop_column;
+
+  /* Make sure this is not an attempt to ALTER a view, virtual table or
+  ** system table. */
+  if( SQLITE_OK!=isAlterableTable(pParse, pTab) ) goto exit_drop_column;
+  if( SQLITE_OK!=isRealTable(pParse, pTab, 1) ) goto exit_drop_column;
+
+  /* Find the index of the column being dropped. */
+  zCol = sqlite3NameFromToken(db, pName);
+  if( zCol==0 ){
+    assert( db->mallocFailed );
+    goto exit_drop_column;
+  }
+  iCol = sqlite3ColumnIndex(pTab, zCol);
+  if( iCol<0 ){
+    sqlite3ErrorMsg(pParse, "no such column: \"%T\"", pName);
+    goto exit_drop_column;
+  }
+
+  /* Do not allow the user to drop a PRIMARY KEY column or a column
+  ** constrained by a UNIQUE constraint.  */
+  if( pTab->aCol[iCol].colFlags & (COLFLAG_PRIMKEY|COLFLAG_UNIQUE) ){
+    sqlite3ErrorMsg(pParse, "cannot drop %s column: \"%s\"",
+        (pTab->aCol[iCol].colFlags&COLFLAG_PRIMKEY) ? "PRIMARY KEY" : "UNIQUE",
+        zCol
+    );
+    goto exit_drop_column;
+  }
+
+  /* Do not allow the number of columns to go to zero */
+  if( pTab->nCol<=1 ){
+    sqlite3ErrorMsg(pParse, "cannot drop column \"%s\": no other columns exist",zCol);
+    goto exit_drop_column;
+  }
+
+  /* Edit the sqlite_schema table */
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb>=0 );
+  zDb = db->aDb[iDb].zDbSName;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Invoke the authorization callback. */
+  if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, zCol) ){
+    goto exit_drop_column;
+  }
+#endif
+  renameTestSchema(pParse, zDb, iDb==1, "", 0);
+  renameFixQuotes(pParse, zDb, iDb==1);
+  sqlite3NestedParse(pParse,
+      "UPDATE \"%w\"." LEGACY_SCHEMA_TABLE " SET "
+      "sql = sqlite_drop_column(%d, sql, %d) "
+      "WHERE (type=='table' AND tbl_name=%Q COLLATE nocase)"
+      , zDb, iDb, iCol, pTab->zName
+  );
+
+  /* Drop and reload the database schema. */
+  renameReloadSchema(pParse, iDb, INITFLAG_AlterDrop);
+  renameTestSchema(pParse, zDb, iDb==1, "after drop column", 1);
+
+  /* Edit rows of table on disk */
+  if( pParse->nErr==0 && (pTab->aCol[iCol].colFlags & COLFLAG_VIRTUAL)==0 ){
+    int i;
+    int addr;
+    int reg;
+    int regRec;
+    Index *pPk = 0;
+    int nField = 0;               /* Number of non-virtual columns after drop */
+    int iCur;
+    Vdbe *v = sqlite3GetVdbe(pParse);
+    iCur = pParse->nTab++;
+    sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite);
+    addr = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
+    reg = ++pParse->nMem;
+    if( HasRowid(pTab) ){
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, reg);
+      pParse->nMem += pTab->nCol;
+    }else{
+      pPk = sqlite3PrimaryKeyIndex(pTab);
+      pParse->nMem += pPk->nColumn;
+      for(i=0; i<pPk->nKeyCol; i++){
+        sqlite3VdbeAddOp3(v, OP_Column, iCur, i, reg+i+1);
+      }
+      nField = pPk->nKeyCol;
+    }
+    regRec = ++pParse->nMem;
+    for(i=0; i<pTab->nCol; i++){
+      if( i!=iCol && (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0 ){
+        int regOut;
+        if( pPk ){
+          int iPos = sqlite3TableColumnToIndex(pPk, i);
+          int iColPos = sqlite3TableColumnToIndex(pPk, iCol);
+          if( iPos<pPk->nKeyCol ) continue;
+          regOut = reg+1+iPos-(iPos>iColPos);
+        }else{
+          regOut = reg+1+nField;
+        }
+        if( i==pTab->iPKey ){
+          sqlite3VdbeAddOp2(v, OP_Null, 0, regOut);
+        }else{
+          char aff = pTab->aCol[i].affinity;
+          if( aff==SQLITE_AFF_REAL ){
+            pTab->aCol[i].affinity = SQLITE_AFF_NUMERIC;
+          }
+          sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, i, regOut);
+          pTab->aCol[i].affinity = aff;
+        }
+        nField++;
+      }
+    }
+    if( nField==0 ){
+      /* dbsqlfuzz 5f09e7bcc78b4954d06bf9f2400d7715f48d1fef */
+      pParse->nMem++;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, reg+1);
+      nField = 1;
+    }
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, reg+1, nField, regRec);
+    if( pPk ){
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iCur, regRec, reg+1, pPk->nKeyCol);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_Insert, iCur, regRec, reg);
+    }
+    sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION);
+
+    sqlite3VdbeAddOp2(v, OP_Next, iCur, addr+1); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr);
+  }
+
+exit_drop_column:
+  sqlite3DbFree(db, zCol);
+  sqlite3SrcListDelete(db, pSrc);
+}
+
+/*
+** Register built-in functions used to help implement ALTER TABLE
+*/
+SQLITE_PRIVATE void sqlite3AlterFunctions(void){
+  static FuncDef aAlterTableFuncs[] = {
+    INTERNAL_FUNCTION(sqlite_rename_column,  9, renameColumnFunc),
+    INTERNAL_FUNCTION(sqlite_rename_table,   7, renameTableFunc),
+    INTERNAL_FUNCTION(sqlite_rename_test,    7, renameTableTest),
+    INTERNAL_FUNCTION(sqlite_drop_column,    3, dropColumnFunc),
+    INTERNAL_FUNCTION(sqlite_rename_quotefix,2, renameQuotefixFunc),
+  };
+  sqlite3InsertBuiltinFuncs(aAlterTableFuncs, ArraySize(aAlterTableFuncs));
+}
+#endif  /* SQLITE_ALTER_TABLE */
+
+/************** End of alter.c ***********************************************/
+/************** Begin file analyze.c *****************************************/
+/*
+** 2005-07-08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code associated with the ANALYZE command.
+**
+** The ANALYZE command gather statistics about the content of tables
+** and indices.  These statistics are made available to the query planner
+** to help it make better decisions about how to perform queries.
+**
+** The following system tables are or have been supported:
+**
+**    CREATE TABLE sqlite_stat1(tbl, idx, stat);
+**    CREATE TABLE sqlite_stat2(tbl, idx, sampleno, sample);
+**    CREATE TABLE sqlite_stat3(tbl, idx, nEq, nLt, nDLt, sample);
+**    CREATE TABLE sqlite_stat4(tbl, idx, nEq, nLt, nDLt, sample);
+**
+** Additional tables might be added in future releases of SQLite.
+** The sqlite_stat2 table is not created or used unless the SQLite version
+** is between 3.6.18 and 3.7.8, inclusive, and unless SQLite is compiled
+** with SQLITE_ENABLE_STAT2.  The sqlite_stat2 table is deprecated.
+** The sqlite_stat2 table is superseded by sqlite_stat3, which is only
+** created and used by SQLite versions 3.7.9 through 3.29.0 when
+** SQLITE_ENABLE_STAT3 defined.  The functionality of sqlite_stat3
+** is a superset of sqlite_stat2 and is also now deprecated.  The
+** sqlite_stat4 is an enhanced version of sqlite_stat3 and is only
+** available when compiled with SQLITE_ENABLE_STAT4 and in SQLite
+** versions 3.8.1 and later.  STAT4 is the only variant that is still
+** supported.
+**
+** For most applications, sqlite_stat1 provides all the statistics required
+** for the query planner to make good choices.
+**
+** Format of sqlite_stat1:
+**
+** There is normally one row per index, with the index identified by the
+** name in the idx column.  The tbl column is the name of the table to
+** which the index belongs.  In each such row, the stat column will be
+** a string consisting of a list of integers.  The first integer in this
+** list is the number of rows in the index.  (This is the same as the
+** number of rows in the table, except for partial indices.)  The second
+** integer is the average number of rows in the index that have the same
+** value in the first column of the index.  The third integer is the average
+** number of rows in the index that have the same value for the first two
+** columns.  The N-th integer (for N>1) is the average number of rows in
+** the index which have the same value for the first N-1 columns.  For
+** a K-column index, there will be K+1 integers in the stat column.  If
+** the index is unique, then the last integer will be 1.
+**
+** The list of integers in the stat column can optionally be followed
+** by the keyword "unordered".  The "unordered" keyword, if it is present,
+** must be separated from the last integer by a single space.  If the
+** "unordered" keyword is present, then the query planner assumes that
+** the index is unordered and will not use the index for a range query.
+**
+** If the sqlite_stat1.idx column is NULL, then the sqlite_stat1.stat
+** column contains a single integer which is the (estimated) number of
+** rows in the table identified by sqlite_stat1.tbl.
+**
+** Format of sqlite_stat2:
+**
+** The sqlite_stat2 is only created and is only used if SQLite is compiled
+** with SQLITE_ENABLE_STAT2 and if the SQLite version number is between
+** 3.6.18 and 3.7.8.  The "stat2" table contains additional information
+** about the distribution of keys within an index.  The index is identified by
+** the "idx" column and the "tbl" column is the name of the table to which
+** the index belongs.  There are usually 10 rows in the sqlite_stat2
+** table for each index.
+**
+** The sqlite_stat2 entries for an index that have sampleno between 0 and 9
+** inclusive are samples of the left-most key value in the index taken at
+** evenly spaced points along the index.  Let the number of samples be S
+** (10 in the standard build) and let C be the number of rows in the index.
+** Then the sampled rows are given by:
+**
+**     rownumber = (i*C*2 + C)/(S*2)
+**
+** For i between 0 and S-1.  Conceptually, the index space is divided into
+** S uniform buckets and the samples are the middle row from each bucket.
+**
+** The format for sqlite_stat2 is recorded here for legacy reference.  This
+** version of SQLite does not support sqlite_stat2.  It neither reads nor
+** writes the sqlite_stat2 table.  This version of SQLite only supports
+** sqlite_stat3.
+**
+** Format for sqlite_stat3:
+**
+** The sqlite_stat3 format is a subset of sqlite_stat4.  Hence, the
+** sqlite_stat4 format will be described first.  Further information
+** about sqlite_stat3 follows the sqlite_stat4 description.
+**
+** Format for sqlite_stat4:
+**
+** As with sqlite_stat2, the sqlite_stat4 table contains histogram data
+** to aid the query planner in choosing good indices based on the values
+** that indexed columns are compared against in the WHERE clauses of
+** queries.
+**
+** The sqlite_stat4 table contains multiple entries for each index.
+** The idx column names the index and the tbl column is the table of the
+** index.  If the idx and tbl columns are the same, then the sample is
+** of the INTEGER PRIMARY KEY.  The sample column is a blob which is the
+** binary encoding of a key from the index.  The nEq column is a
+** list of integers.  The first integer is the approximate number
+** of entries in the index whose left-most column exactly matches
+** the left-most column of the sample.  The second integer in nEq
+** is the approximate number of entries in the index where the
+** first two columns match the first two columns of the sample.
+** And so forth.  nLt is another list of integers that show the approximate
+** number of entries that are strictly less than the sample.  The first
+** integer in nLt contains the number of entries in the index where the
+** left-most column is less than the left-most column of the sample.
+** The K-th integer in the nLt entry is the number of index entries
+** where the first K columns are less than the first K columns of the
+** sample.  The nDLt column is like nLt except that it contains the
+** number of distinct entries in the index that are less than the
+** sample.
+**
+** There can be an arbitrary number of sqlite_stat4 entries per index.
+** The ANALYZE command will typically generate sqlite_stat4 tables
+** that contain between 10 and 40 samples which are distributed across
+** the key space, though not uniformly, and which include samples with
+** large nEq values.
+**
+** Format for sqlite_stat3 redux:
+**
+** The sqlite_stat3 table is like sqlite_stat4 except that it only
+** looks at the left-most column of the index.  The sqlite_stat3.sample
+** column contains the actual value of the left-most column instead
+** of a blob encoding of the complete index key as is found in
+** sqlite_stat4.sample.  The nEq, nLt, and nDLt entries of sqlite_stat3
+** all contain just a single integer which is the same as the first
+** integer in the equivalent columns in sqlite_stat4.
+*/
+#ifndef SQLITE_OMIT_ANALYZE
+/* #include "sqliteInt.h" */
+
+#if defined(SQLITE_ENABLE_STAT4)
+# define IsStat4     1
+#else
+# define IsStat4     0
+# undef SQLITE_STAT4_SAMPLES
+# define SQLITE_STAT4_SAMPLES 1
+#endif
+
+/*
+** This routine generates code that opens the sqlite_statN tables.
+** The sqlite_stat1 table is always relevant.  sqlite_stat2 is now
+** obsolete.  sqlite_stat3 and sqlite_stat4 are only opened when
+** appropriate compile-time options are provided.
+**
+** If the sqlite_statN tables do not previously exist, it is created.
+**
+** Argument zWhere may be a pointer to a buffer containing a table name,
+** or it may be a NULL pointer. If it is not NULL, then all entries in
+** the sqlite_statN tables associated with the named table are deleted.
+** If zWhere==0, then code is generated to delete all stat table entries.
+*/
+static void openStatTable(
+  Parse *pParse,          /* Parsing context */
+  int iDb,                /* The database we are looking in */
+  int iStatCur,           /* Open the sqlite_stat1 table on this cursor */
+  const char *zWhere,     /* Delete entries for this table or index */
+  const char *zWhereType  /* Either "tbl" or "idx" */
+){
+  static const struct {
+    const char *zName;
+    const char *zCols;
+  } aTable[] = {
+    { "sqlite_stat1", "tbl,idx,stat" },
+#if defined(SQLITE_ENABLE_STAT4)
+    { "sqlite_stat4", "tbl,idx,neq,nlt,ndlt,sample" },
+#else
+    { "sqlite_stat4", 0 },
+#endif
+    { "sqlite_stat3", 0 },
+  };
+  int i;
+  sqlite3 *db = pParse->db;
+  Db *pDb;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  u32 aRoot[ArraySize(aTable)];
+  u8 aCreateTbl[ArraySize(aTable)];
+#ifdef SQLITE_ENABLE_STAT4
+  const int nToOpen = OptimizationEnabled(db,SQLITE_Stat4) ? 2 : 1;
+#else
+  const int nToOpen = 1;
+#endif
+
+  if( v==0 ) return;
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  assert( sqlite3VdbeDb(v)==db );
+  pDb = &db->aDb[iDb];
+
+  /* Create new statistic tables if they do not exist, or clear them
+  ** if they do already exist.
+  */
+  for(i=0; i<ArraySize(aTable); i++){
+    const char *zTab = aTable[i].zName;
+    Table *pStat;
+    aCreateTbl[i] = 0;
+    if( (pStat = sqlite3FindTable(db, zTab, pDb->zDbSName))==0 ){
+      if( i<nToOpen ){
+        /* The sqlite_statN table does not exist. Create it. Note that a
+        ** side-effect of the CREATE TABLE statement is to leave the rootpage
+        ** of the new table in register pParse->regRoot. This is important
+        ** because the OpenWrite opcode below will be needing it. */
+        sqlite3NestedParse(pParse,
+            "CREATE TABLE %Q.%s(%s)", pDb->zDbSName, zTab, aTable[i].zCols
+        );
+        aRoot[i] = (u32)pParse->regRoot;
+        aCreateTbl[i] = OPFLAG_P2ISREG;
+      }
+    }else{
+      /* The table already exists. If zWhere is not NULL, delete all entries
+      ** associated with the table zWhere. If zWhere is NULL, delete the
+      ** entire contents of the table. */
+      aRoot[i] = pStat->tnum;
+      sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab);
+      if( zWhere ){
+        sqlite3NestedParse(pParse,
+           "DELETE FROM %Q.%s WHERE %s=%Q",
+           pDb->zDbSName, zTab, zWhereType, zWhere
+        );
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+      }else if( db->xPreUpdateCallback ){
+        sqlite3NestedParse(pParse, "DELETE FROM %Q.%s", pDb->zDbSName, zTab);
+#endif
+      }else{
+        /* The sqlite_stat[134] table already exists.  Delete all rows. */
+        sqlite3VdbeAddOp2(v, OP_Clear, (int)aRoot[i], iDb);
+      }
+    }
+  }
+
+  /* Open the sqlite_stat[134] tables for writing. */
+  for(i=0; i<nToOpen; i++){
+    assert( i<ArraySize(aTable) );
+    sqlite3VdbeAddOp4Int(v, OP_OpenWrite, iStatCur+i, (int)aRoot[i], iDb, 3);
+    sqlite3VdbeChangeP5(v, aCreateTbl[i]);
+    VdbeComment((v, aTable[i].zName));
+  }
+}
+
+/*
+** Recommended number of samples for sqlite_stat4
+*/
+#ifndef SQLITE_STAT4_SAMPLES
+# define SQLITE_STAT4_SAMPLES 24
+#endif
+
+/*
+** Three SQL functions - stat_init(), stat_push(), and stat_get() -
+** share an instance of the following structure to hold their state
+** information.
+*/
+typedef struct StatAccum StatAccum;
+typedef struct StatSample StatSample;
+struct StatSample {
+  tRowcnt *anDLt;                 /* sqlite_stat4.nDLt */
+#ifdef SQLITE_ENABLE_STAT4
+  tRowcnt *anEq;                  /* sqlite_stat4.nEq */
+  tRowcnt *anLt;                  /* sqlite_stat4.nLt */
+  union {
+    i64 iRowid;                     /* Rowid in main table of the key */
+    u8 *aRowid;                     /* Key for WITHOUT ROWID tables */
+  } u;
+  u32 nRowid;                     /* Sizeof aRowid[] */
+  u8 isPSample;                   /* True if a periodic sample */
+  int iCol;                       /* If !isPSample, the reason for inclusion */
+  u32 iHash;                      /* Tiebreaker hash */
+#endif
+};
+struct StatAccum {
+  sqlite3 *db;              /* Database connection, for malloc() */
+  tRowcnt nEst;             /* Estimated number of rows */
+  tRowcnt nRow;             /* Number of rows visited so far */
+  int nLimit;               /* Analysis row-scan limit */
+  int nCol;                 /* Number of columns in index + pk/rowid */
+  int nKeyCol;              /* Number of index columns w/o the pk/rowid */
+  u8 nSkipAhead;            /* Number of times of skip-ahead */
+  StatSample current;       /* Current row as a StatSample */
+#ifdef SQLITE_ENABLE_STAT4
+  tRowcnt nPSample;         /* How often to do a periodic sample */
+  int mxSample;             /* Maximum number of samples to accumulate */
+  u32 iPrn;                 /* Pseudo-random number used for sampling */
+  StatSample *aBest;        /* Array of nCol best samples */
+  int iMin;                 /* Index in a[] of entry with minimum score */
+  int nSample;              /* Current number of samples */
+  int nMaxEqZero;           /* Max leading 0 in anEq[] for any a[] entry */
+  int iGet;                 /* Index of current sample accessed by stat_get() */
+  StatSample *a;            /* Array of mxSample StatSample objects */
+#endif
+};
+
+/* Reclaim memory used by a StatSample
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static void sampleClear(sqlite3 *db, StatSample *p){
+  assert( db!=0 );
+  if( p->nRowid ){
+    sqlite3DbFree(db, p->u.aRowid);
+    p->nRowid = 0;
+  }
+}
+#endif
+
+/* Initialize the BLOB value of a ROWID
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static void sampleSetRowid(sqlite3 *db, StatSample *p, int n, const u8 *pData){
+  assert( db!=0 );
+  if( p->nRowid ) sqlite3DbFree(db, p->u.aRowid);
+  p->u.aRowid = sqlite3DbMallocRawNN(db, n);
+  if( p->u.aRowid ){
+    p->nRowid = n;
+    memcpy(p->u.aRowid, pData, n);
+  }else{
+    p->nRowid = 0;
+  }
+}
+#endif
+
+/* Initialize the INTEGER value of a ROWID.
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static void sampleSetRowidInt64(sqlite3 *db, StatSample *p, i64 iRowid){
+  assert( db!=0 );
+  if( p->nRowid ) sqlite3DbFree(db, p->u.aRowid);
+  p->nRowid = 0;
+  p->u.iRowid = iRowid;
+}
+#endif
+
+
+/*
+** Copy the contents of object (*pFrom) into (*pTo).
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static void sampleCopy(StatAccum *p, StatSample *pTo, StatSample *pFrom){
+  pTo->isPSample = pFrom->isPSample;
+  pTo->iCol = pFrom->iCol;
+  pTo->iHash = pFrom->iHash;
+  memcpy(pTo->anEq, pFrom->anEq, sizeof(tRowcnt)*p->nCol);
+  memcpy(pTo->anLt, pFrom->anLt, sizeof(tRowcnt)*p->nCol);
+  memcpy(pTo->anDLt, pFrom->anDLt, sizeof(tRowcnt)*p->nCol);
+  if( pFrom->nRowid ){
+    sampleSetRowid(p->db, pTo, pFrom->nRowid, pFrom->u.aRowid);
+  }else{
+    sampleSetRowidInt64(p->db, pTo, pFrom->u.iRowid);
+  }
+}
+#endif
+
+/*
+** Reclaim all memory of a StatAccum structure.
+*/
+static void statAccumDestructor(void *pOld){
+  StatAccum *p = (StatAccum*)pOld;
+#ifdef SQLITE_ENABLE_STAT4
+  if( p->mxSample ){
+    int i;
+    for(i=0; i<p->nCol; i++) sampleClear(p->db, p->aBest+i);
+    for(i=0; i<p->mxSample; i++) sampleClear(p->db, p->a+i);
+    sampleClear(p->db, &p->current);
+  }
+#endif
+  sqlite3DbFree(p->db, p);
+}
+
+/*
+** Implementation of the stat_init(N,K,C,L) SQL function. The four parameters
+** are:
+**     N:    The number of columns in the index including the rowid/pk (note 1)
+**     K:    The number of columns in the index excluding the rowid/pk.
+**     C:    Estimated number of rows in the index
+**     L:    A limit on the number of rows to scan, or 0 for no-limit
+**
+** Note 1:  In the special case of the covering index that implements a
+** WITHOUT ROWID table, N is the number of PRIMARY KEY columns, not the
+** total number of columns in the table.
+**
+** For indexes on ordinary rowid tables, N==K+1.  But for indexes on
+** WITHOUT ROWID tables, N=K+P where P is the number of columns in the
+** PRIMARY KEY of the table.  The covering index that implements the
+** original WITHOUT ROWID table as N==K as a special case.
+**
+** This routine allocates the StatAccum object in heap memory. The return
+** value is a pointer to the StatAccum object.  The datatype of the
+** return value is BLOB, but it is really just a pointer to the StatAccum
+** object.
+*/
+static void statInit(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  StatAccum *p;
+  int nCol;                       /* Number of columns in index being sampled */
+  int nKeyCol;                    /* Number of key columns */
+  int nColUp;                     /* nCol rounded up for alignment */
+  int n;                          /* Bytes of space to allocate */
+  sqlite3 *db = sqlite3_context_db_handle(context);   /* Database connection */
+#ifdef SQLITE_ENABLE_STAT4
+  /* Maximum number of samples.  0 if STAT4 data is not collected */
+  int mxSample = OptimizationEnabled(db,SQLITE_Stat4) ?SQLITE_STAT4_SAMPLES :0;
+#endif
+
+  /* Decode the three function arguments */
+  UNUSED_PARAMETER(argc);
+  nCol = sqlite3_value_int(argv[0]);
+  assert( nCol>0 );
+  nColUp = sizeof(tRowcnt)<8 ? (nCol+1)&~1 : nCol;
+  nKeyCol = sqlite3_value_int(argv[1]);
+  assert( nKeyCol<=nCol );
+  assert( nKeyCol>0 );
+
+  /* Allocate the space required for the StatAccum object */
+  n = sizeof(*p)
+    + sizeof(tRowcnt)*nColUp;                    /* StatAccum.anDLt */
+#ifdef SQLITE_ENABLE_STAT4
+  n += sizeof(tRowcnt)*nColUp;                   /* StatAccum.anEq */
+  if( mxSample ){
+    n += sizeof(tRowcnt)*nColUp                  /* StatAccum.anLt */
+      + sizeof(StatSample)*(nCol+mxSample)       /* StatAccum.aBest[], a[] */
+      + sizeof(tRowcnt)*3*nColUp*(nCol+mxSample);
+  }
+#endif
+  p = sqlite3DbMallocZero(db, n);
+  if( p==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+
+  p->db = db;
+  p->nEst = sqlite3_value_int64(argv[2]);
+  p->nRow = 0;
+  p->nLimit = sqlite3_value_int64(argv[3]);
+  p->nCol = nCol;
+  p->nKeyCol = nKeyCol;
+  p->nSkipAhead = 0;
+  p->current.anDLt = (tRowcnt*)&p[1];
+
+#ifdef SQLITE_ENABLE_STAT4
+  p->current.anEq = &p->current.anDLt[nColUp];
+  p->mxSample = p->nLimit==0 ? mxSample : 0;
+  if( mxSample ){
+    u8 *pSpace;                     /* Allocated space not yet assigned */
+    int i;                          /* Used to iterate through p->aSample[] */
+
+    p->iGet = -1;
+    p->nPSample = (tRowcnt)(p->nEst/(mxSample/3+1) + 1);
+    p->current.anLt = &p->current.anEq[nColUp];
+    p->iPrn = 0x689e962d*(u32)nCol ^ 0xd0944565*(u32)sqlite3_value_int(argv[2]);
+
+    /* Set up the StatAccum.a[] and aBest[] arrays */
+    p->a = (struct StatSample*)&p->current.anLt[nColUp];
+    p->aBest = &p->a[mxSample];
+    pSpace = (u8*)(&p->a[mxSample+nCol]);
+    for(i=0; i<(mxSample+nCol); i++){
+      p->a[i].anEq = (tRowcnt *)pSpace; pSpace += (sizeof(tRowcnt) * nColUp);
+      p->a[i].anLt = (tRowcnt *)pSpace; pSpace += (sizeof(tRowcnt) * nColUp);
+      p->a[i].anDLt = (tRowcnt *)pSpace; pSpace += (sizeof(tRowcnt) * nColUp);
+    }
+    assert( (pSpace - (u8*)p)==n );
+
+    for(i=0; i<nCol; i++){
+      p->aBest[i].iCol = i;
+    }
+  }
+#endif
+
+  /* Return a pointer to the allocated object to the caller.  Note that
+  ** only the pointer (the 2nd parameter) matters.  The size of the object
+  ** (given by the 3rd parameter) is never used and can be any positive
+  ** value. */
+  sqlite3_result_blob(context, p, sizeof(*p), statAccumDestructor);
+}
+static const FuncDef statInitFuncdef = {
+  4,               /* nArg */
+  SQLITE_UTF8,     /* funcFlags */
+  0,               /* pUserData */
+  0,               /* pNext */
+  statInit,        /* xSFunc */
+  0,               /* xFinalize */
+  0, 0,            /* xValue, xInverse */
+  "stat_init",     /* zName */
+  {0}
+};
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** pNew and pOld are both candidate non-periodic samples selected for
+** the same column (pNew->iCol==pOld->iCol). Ignoring this column and
+** considering only any trailing columns and the sample hash value, this
+** function returns true if sample pNew is to be preferred over pOld.
+** In other words, if we assume that the cardinalities of the selected
+** column for pNew and pOld are equal, is pNew to be preferred over pOld.
+**
+** This function assumes that for each argument sample, the contents of
+** the anEq[] array from pSample->anEq[pSample->iCol+1] onwards are valid.
+*/
+static int sampleIsBetterPost(
+  StatAccum *pAccum,
+  StatSample *pNew,
+  StatSample *pOld
+){
+  int nCol = pAccum->nCol;
+  int i;
+  assert( pNew->iCol==pOld->iCol );
+  for(i=pNew->iCol+1; i<nCol; i++){
+    if( pNew->anEq[i]>pOld->anEq[i] ) return 1;
+    if( pNew->anEq[i]<pOld->anEq[i] ) return 0;
+  }
+  if( pNew->iHash>pOld->iHash ) return 1;
+  return 0;
+}
+#endif
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Return true if pNew is to be preferred over pOld.
+**
+** This function assumes that for each argument sample, the contents of
+** the anEq[] array from pSample->anEq[pSample->iCol] onwards are valid.
+*/
+static int sampleIsBetter(
+  StatAccum *pAccum,
+  StatSample *pNew,
+  StatSample *pOld
+){
+  tRowcnt nEqNew = pNew->anEq[pNew->iCol];
+  tRowcnt nEqOld = pOld->anEq[pOld->iCol];
+
+  assert( pOld->isPSample==0 && pNew->isPSample==0 );
+  assert( IsStat4 || (pNew->iCol==0 && pOld->iCol==0) );
+
+  if( (nEqNew>nEqOld) ) return 1;
+  if( nEqNew==nEqOld ){
+    if( pNew->iCol<pOld->iCol ) return 1;
+    return (pNew->iCol==pOld->iCol && sampleIsBetterPost(pAccum, pNew, pOld));
+  }
+  return 0;
+}
+
+/*
+** Copy the contents of sample *pNew into the p->a[] array. If necessary,
+** remove the least desirable sample from p->a[] to make room.
+*/
+static void sampleInsert(StatAccum *p, StatSample *pNew, int nEqZero){
+  StatSample *pSample = 0;
+  int i;
+
+  assert( IsStat4 || nEqZero==0 );
+
+  /* StatAccum.nMaxEqZero is set to the maximum number of leading 0
+  ** values in the anEq[] array of any sample in StatAccum.a[]. In
+  ** other words, if nMaxEqZero is n, then it is guaranteed that there
+  ** are no samples with StatSample.anEq[m]==0 for (m>=n). */
+  if( nEqZero>p->nMaxEqZero ){
+    p->nMaxEqZero = nEqZero;
+  }
+  if( pNew->isPSample==0 ){
+    StatSample *pUpgrade = 0;
+    assert( pNew->anEq[pNew->iCol]>0 );
+
+    /* This sample is being added because the prefix that ends in column
+    ** iCol occurs many times in the table. However, if we have already
+    ** added a sample that shares this prefix, there is no need to add
+    ** this one. Instead, upgrade the priority of the highest priority
+    ** existing sample that shares this prefix.  */
+    for(i=p->nSample-1; i>=0; i--){
+      StatSample *pOld = &p->a[i];
+      if( pOld->anEq[pNew->iCol]==0 ){
+        if( pOld->isPSample ) return;
+        assert( pOld->iCol>pNew->iCol );
+        assert( sampleIsBetter(p, pNew, pOld) );
+        if( pUpgrade==0 || sampleIsBetter(p, pOld, pUpgrade) ){
+          pUpgrade = pOld;
+        }
+      }
+    }
+    if( pUpgrade ){
+      pUpgrade->iCol = pNew->iCol;
+      pUpgrade->anEq[pUpgrade->iCol] = pNew->anEq[pUpgrade->iCol];
+      goto find_new_min;
+    }
+  }
+
+  /* If necessary, remove sample iMin to make room for the new sample. */
+  if( p->nSample>=p->mxSample ){
+    StatSample *pMin = &p->a[p->iMin];
+    tRowcnt *anEq = pMin->anEq;
+    tRowcnt *anLt = pMin->anLt;
+    tRowcnt *anDLt = pMin->anDLt;
+    sampleClear(p->db, pMin);
+    memmove(pMin, &pMin[1], sizeof(p->a[0])*(p->nSample-p->iMin-1));
+    pSample = &p->a[p->nSample-1];
+    pSample->nRowid = 0;
+    pSample->anEq = anEq;
+    pSample->anDLt = anDLt;
+    pSample->anLt = anLt;
+    p->nSample = p->mxSample-1;
+  }
+
+  /* The "rows less-than" for the rowid column must be greater than that
+  ** for the last sample in the p->a[] array. Otherwise, the samples would
+  ** be out of order. */
+  assert( p->nSample==0
+       || pNew->anLt[p->nCol-1] > p->a[p->nSample-1].anLt[p->nCol-1] );
+
+  /* Insert the new sample */
+  pSample = &p->a[p->nSample];
+  sampleCopy(p, pSample, pNew);
+  p->nSample++;
+
+  /* Zero the first nEqZero entries in the anEq[] array. */
+  memset(pSample->anEq, 0, sizeof(tRowcnt)*nEqZero);
+
+find_new_min:
+  if( p->nSample>=p->mxSample ){
+    int iMin = -1;
+    for(i=0; i<p->mxSample; i++){
+      if( p->a[i].isPSample ) continue;
+      if( iMin<0 || sampleIsBetter(p, &p->a[iMin], &p->a[i]) ){
+        iMin = i;
+      }
+    }
+    assert( iMin>=0 );
+    p->iMin = iMin;
+  }
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Field iChng of the index being scanned has changed. So at this point
+** p->current contains a sample that reflects the previous row of the
+** index. The value of anEq[iChng] and subsequent anEq[] elements are
+** correct at this point.
+*/
+static void samplePushPrevious(StatAccum *p, int iChng){
+  int i;
+
+  /* Check if any samples from the aBest[] array should be pushed
+  ** into IndexSample.a[] at this point.  */
+  for(i=(p->nCol-2); i>=iChng; i--){
+    StatSample *pBest = &p->aBest[i];
+    pBest->anEq[i] = p->current.anEq[i];
+    if( p->nSample<p->mxSample || sampleIsBetter(p, pBest, &p->a[p->iMin]) ){
+      sampleInsert(p, pBest, i);
+    }
+  }
+
+  /* Check that no sample contains an anEq[] entry with an index of
+  ** p->nMaxEqZero or greater set to zero. */
+  for(i=p->nSample-1; i>=0; i--){
+    int j;
+    for(j=p->nMaxEqZero; j<p->nCol; j++) assert( p->a[i].anEq[j]>0 );
+  }
+
+  /* Update the anEq[] fields of any samples already collected. */
+  if( iChng<p->nMaxEqZero ){
+    for(i=p->nSample-1; i>=0; i--){
+      int j;
+      for(j=iChng; j<p->nCol; j++){
+        if( p->a[i].anEq[j]==0 ) p->a[i].anEq[j] = p->current.anEq[j];
+      }
+    }
+    p->nMaxEqZero = iChng;
+  }
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+/*
+** Implementation of the stat_push SQL function:  stat_push(P,C,R)
+** Arguments:
+**
+**    P     Pointer to the StatAccum object created by stat_init()
+**    C     Index of left-most column to differ from previous row
+**    R     Rowid for the current row.  Might be a key record for
+**          WITHOUT ROWID tables.
+**
+** The purpose of this routine is to collect statistical data and/or
+** samples from the index being analyzed into the StatAccum object.
+** The stat_get() SQL function will be used afterwards to
+** retrieve the information gathered.
+**
+** This SQL function usually returns NULL, but might return an integer
+** if it wants the byte-code to do special processing.
+**
+** The R parameter is only used for STAT4
+*/
+static void statPush(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+
+  /* The three function arguments */
+  StatAccum *p = (StatAccum*)sqlite3_value_blob(argv[0]);
+  int iChng = sqlite3_value_int(argv[1]);
+
+  UNUSED_PARAMETER( argc );
+  UNUSED_PARAMETER( context );
+  assert( p->nCol>0 );
+  assert( iChng<p->nCol );
+
+  if( p->nRow==0 ){
+    /* This is the first call to this function. Do initialization. */
+#ifdef SQLITE_ENABLE_STAT4
+    for(i=0; i<p->nCol; i++) p->current.anEq[i] = 1;
+#endif
+  }else{
+    /* Second and subsequent calls get processed here */
+#ifdef SQLITE_ENABLE_STAT4
+    if( p->mxSample ) samplePushPrevious(p, iChng);
+#endif
+
+    /* Update anDLt[], anLt[] and anEq[] to reflect the values that apply
+    ** to the current row of the index. */
+#ifdef SQLITE_ENABLE_STAT4
+    for(i=0; i<iChng; i++){
+      p->current.anEq[i]++;
+    }
+#endif
+    for(i=iChng; i<p->nCol; i++){
+      p->current.anDLt[i]++;
+#ifdef SQLITE_ENABLE_STAT4
+      if( p->mxSample ) p->current.anLt[i] += p->current.anEq[i];
+      p->current.anEq[i] = 1;
+#endif
+    }
+  }
+
+  p->nRow++;
+#ifdef SQLITE_ENABLE_STAT4
+  if( p->mxSample ){
+    tRowcnt nLt;
+    if( sqlite3_value_type(argv[2])==SQLITE_INTEGER ){
+      sampleSetRowidInt64(p->db, &p->current, sqlite3_value_int64(argv[2]));
+    }else{
+      sampleSetRowid(p->db, &p->current, sqlite3_value_bytes(argv[2]),
+                                         sqlite3_value_blob(argv[2]));
+    }
+    p->current.iHash = p->iPrn = p->iPrn*1103515245 + 12345;
+
+    nLt = p->current.anLt[p->nCol-1];
+    /* Check if this is to be a periodic sample. If so, add it. */
+    if( (nLt/p->nPSample)!=(nLt+1)/p->nPSample ){
+      p->current.isPSample = 1;
+      p->current.iCol = 0;
+      sampleInsert(p, &p->current, p->nCol-1);
+      p->current.isPSample = 0;
+    }
+
+    /* Update the aBest[] array. */
+    for(i=0; i<(p->nCol-1); i++){
+      p->current.iCol = i;
+      if( i>=iChng || sampleIsBetterPost(p, &p->current, &p->aBest[i]) ){
+        sampleCopy(p, &p->aBest[i], &p->current);
+      }
+    }
+  }else
+#endif
+  if( p->nLimit && p->nRow>(tRowcnt)p->nLimit*(p->nSkipAhead+1) ){
+    p->nSkipAhead++;
+    sqlite3_result_int(context, p->current.anDLt[0]>0);
+  }
+}
+
+static const FuncDef statPushFuncdef = {
+  2+IsStat4,       /* nArg */
+  SQLITE_UTF8,     /* funcFlags */
+  0,               /* pUserData */
+  0,               /* pNext */
+  statPush,        /* xSFunc */
+  0,               /* xFinalize */
+  0, 0,            /* xValue, xInverse */
+  "stat_push",     /* zName */
+  {0}
+};
+
+#define STAT_GET_STAT1 0          /* "stat" column of stat1 table */
+#define STAT_GET_ROWID 1          /* "rowid" column of stat[34] entry */
+#define STAT_GET_NEQ   2          /* "neq" column of stat[34] entry */
+#define STAT_GET_NLT   3          /* "nlt" column of stat[34] entry */
+#define STAT_GET_NDLT  4          /* "ndlt" column of stat[34] entry */
+
+/*
+** Implementation of the stat_get(P,J) SQL function.  This routine is
+** used to query statistical information that has been gathered into
+** the StatAccum object by prior calls to stat_push().  The P parameter
+** has type BLOB but it is really just a pointer to the StatAccum object.
+** The content to returned is determined by the parameter J
+** which is one of the STAT_GET_xxxx values defined above.
+**
+** The stat_get(P,J) function is not available to generic SQL.  It is
+** inserted as part of a manually constructed bytecode program.  (See
+** the callStatGet() routine below.)  It is guaranteed that the P
+** parameter will always be a pointer to a StatAccum object, never a
+** NULL.
+**
+** If STAT4 is not enabled, then J is always
+** STAT_GET_STAT1 and is hence omitted and this routine becomes
+** a one-parameter function, stat_get(P), that always returns the
+** stat1 table entry information.
+*/
+static void statGet(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  StatAccum *p = (StatAccum*)sqlite3_value_blob(argv[0]);
+#ifdef SQLITE_ENABLE_STAT4
+  /* STAT4 has a parameter on this routine. */
+  int eCall = sqlite3_value_int(argv[1]);
+  assert( argc==2 );
+  assert( eCall==STAT_GET_STAT1 || eCall==STAT_GET_NEQ
+       || eCall==STAT_GET_ROWID || eCall==STAT_GET_NLT
+       || eCall==STAT_GET_NDLT
+  );
+  assert( eCall==STAT_GET_STAT1 || p->mxSample );
+  if( eCall==STAT_GET_STAT1 )
+#else
+  assert( argc==1 );
+#endif
+  {
+    /* Return the value to store in the "stat" column of the sqlite_stat1
+    ** table for this index.
+    **
+    ** The value is a string composed of a list of integers describing
+    ** the index. The first integer in the list is the total number of
+    ** entries in the index. There is one additional integer in the list
+    ** for each indexed column. This additional integer is an estimate of
+    ** the number of rows matched by a equality query on the index using
+    ** a key with the corresponding number of fields. In other words,
+    ** if the index is on columns (a,b) and the sqlite_stat1 value is
+    ** "100 10 2", then SQLite estimates that:
+    **
+    **   * the index contains 100 rows,
+    **   * "WHERE a=?" matches 10 rows, and
+    **   * "WHERE a=? AND b=?" matches 2 rows.
+    **
+    ** If D is the count of distinct values and K is the total number of
+    ** rows, then each estimate is usually computed as:
+    **
+    **        I = (K+D-1)/D
+    **
+    ** In other words, I is K/D rounded up to the next whole integer.
+    ** However, if I is between 1.0 and 1.1 (in other words if I is
+    ** close to 1.0 but just a little larger) then do not round up but
+    ** instead keep the I value at 1.0.
+    */
+    sqlite3_str sStat;   /* Text of the constructed "stat" line */
+    int i;               /* Loop counter */
+
+    sqlite3StrAccumInit(&sStat, 0, 0, 0, (p->nKeyCol+1)*100);
+    sqlite3_str_appendf(&sStat, "%llu",
+        p->nSkipAhead ? (u64)p->nEst : (u64)p->nRow);
+    for(i=0; i<p->nKeyCol; i++){
+      u64 nDistinct = p->current.anDLt[i] + 1;
+      u64 iVal = (p->nRow + nDistinct - 1) / nDistinct;
+      if( iVal==2 && p->nRow*10 <= nDistinct*11 ) iVal = 1;
+      sqlite3_str_appendf(&sStat, " %llu", iVal);
+#ifdef SQLITE_ENABLE_STAT4
+      assert( p->current.anEq[i] || p->nRow==0 );
+#endif
+    }
+    sqlite3ResultStrAccum(context, &sStat);
+  }
+#ifdef SQLITE_ENABLE_STAT4
+  else if( eCall==STAT_GET_ROWID ){
+    if( p->iGet<0 ){
+      samplePushPrevious(p, 0);
+      p->iGet = 0;
+    }
+    if( p->iGet<p->nSample ){
+      StatSample *pS = p->a + p->iGet;
+      if( pS->nRowid==0 ){
+        sqlite3_result_int64(context, pS->u.iRowid);
+      }else{
+        sqlite3_result_blob(context, pS->u.aRowid, pS->nRowid,
+                            SQLITE_TRANSIENT);
+      }
+    }
+  }else{
+    tRowcnt *aCnt = 0;
+    sqlite3_str sStat;
+    int i;
+
+    assert( p->iGet<p->nSample );
+    switch( eCall ){
+      case STAT_GET_NEQ:  aCnt = p->a[p->iGet].anEq; break;
+      case STAT_GET_NLT:  aCnt = p->a[p->iGet].anLt; break;
+      default: {
+        aCnt = p->a[p->iGet].anDLt;
+        p->iGet++;
+        break;
+      }
+    }
+    sqlite3StrAccumInit(&sStat, 0, 0, 0, p->nCol*100);
+    for(i=0; i<p->nCol; i++){
+      sqlite3_str_appendf(&sStat, "%llu ", (u64)aCnt[i]);
+    }
+    if( sStat.nChar ) sStat.nChar--;
+    sqlite3ResultStrAccum(context, &sStat);
+  }
+#endif /* SQLITE_ENABLE_STAT4 */
+#ifndef SQLITE_DEBUG
+  UNUSED_PARAMETER( argc );
+#endif
+}
+static const FuncDef statGetFuncdef = {
+  1+IsStat4,       /* nArg */
+  SQLITE_UTF8,     /* funcFlags */
+  0,               /* pUserData */
+  0,               /* pNext */
+  statGet,         /* xSFunc */
+  0,               /* xFinalize */
+  0, 0,            /* xValue, xInverse */
+  "stat_get",      /* zName */
+  {0}
+};
+
+static void callStatGet(Parse *pParse, int regStat, int iParam, int regOut){
+#ifdef SQLITE_ENABLE_STAT4
+  sqlite3VdbeAddOp2(pParse->pVdbe, OP_Integer, iParam, regStat+1);
+#elif SQLITE_DEBUG
+  assert( iParam==STAT_GET_STAT1 );
+#else
+  UNUSED_PARAMETER( iParam );
+#endif
+  assert( regOut!=regStat && regOut!=regStat+1 );
+  sqlite3VdbeAddFunctionCall(pParse, 0, regStat, regOut, 1+IsStat4,
+                             &statGetFuncdef, 0);
+}
+
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+/* Add a comment to the most recent VDBE opcode that is the name
+** of the k-th column of the pIdx index.
+*/
+static void analyzeVdbeCommentIndexWithColumnName(
+  Vdbe *v,         /* Prepared statement under construction */
+  Index *pIdx,     /* Index whose column is being loaded */
+  int k            /* Which column index */
+){
+  int i;           /* Index of column in the table */
+  assert( k>=0 && k<pIdx->nColumn );
+  i = pIdx->aiColumn[k];
+  if( NEVER(i==XN_ROWID) ){
+    VdbeComment((v,"%s.rowid",pIdx->zName));
+  }else if( i==XN_EXPR ){
+    assert( pIdx->bHasExpr );
+    VdbeComment((v,"%s.expr(%d)",pIdx->zName, k));
+  }else{
+    VdbeComment((v,"%s.%s", pIdx->zName, pIdx->pTable->aCol[i].zCnName));
+  }
+}
+#else
+# define analyzeVdbeCommentIndexWithColumnName(a,b,c)
+#endif /* SQLITE_DEBUG */
+
+/*
+** Generate code to do an analysis of all indices associated with
+** a single table.
+*/
+static void analyzeOneTable(
+  Parse *pParse,   /* Parser context */
+  Table *pTab,     /* Table whose indices are to be analyzed */
+  Index *pOnlyIdx, /* If not NULL, only analyze this one index */
+  int iStatCur,    /* Index of VdbeCursor that writes the sqlite_stat1 table */
+  int iMem,        /* Available memory locations begin here */
+  int iTab         /* Next available cursor */
+){
+  sqlite3 *db = pParse->db;    /* Database handle */
+  Index *pIdx;                 /* An index to being analyzed */
+  int iIdxCur;                 /* Cursor open on index being analyzed */
+  int iTabCur;                 /* Table cursor */
+  Vdbe *v;                     /* The virtual machine being built up */
+  int i;                       /* Loop counter */
+  int jZeroRows = -1;          /* Jump from here if number of rows is zero */
+  int iDb;                     /* Index of database containing pTab */
+  u8 needTableCnt = 1;         /* True to count the table */
+  int regNewRowid = iMem++;    /* Rowid for the inserted record */
+  int regStat = iMem++;        /* Register to hold StatAccum object */
+  int regChng = iMem++;        /* Index of changed index field */
+  int regRowid = iMem++;       /* Rowid argument passed to stat_push() */
+  int regTemp = iMem++;        /* Temporary use register */
+  int regTemp2 = iMem++;       /* Second temporary use register */
+  int regTabname = iMem++;     /* Register containing table name */
+  int regIdxname = iMem++;     /* Register containing index name */
+  int regStat1 = iMem++;       /* Value for the stat column of sqlite_stat1 */
+  int regPrev = iMem;          /* MUST BE LAST (see below) */
+#ifdef SQLITE_ENABLE_STAT4
+  int doOnce = 1;              /* Flag for a one-time computation */
+#endif
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  Table *pStat1 = 0;
+#endif
+
+  sqlite3TouchRegister(pParse, iMem);
+  assert( sqlite3NoTempsInRange(pParse, regNewRowid, iMem) );
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 || NEVER(pTab==0) ){
+    return;
+  }
+  if( !IsOrdinaryTable(pTab) ){
+    /* Do not gather statistics on views or virtual tables */
+    return;
+  }
+  if( sqlite3_strlike("sqlite\\_%", pTab->zName, '\\')==0 ){
+    /* Do not gather statistics on system tables */
+    return;
+  }
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb>=0 );
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0,
+      db->aDb[iDb].zDbSName ) ){
+    return;
+  }
+#endif
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+  if( db->xPreUpdateCallback ){
+    pStat1 = (Table*)sqlite3DbMallocZero(db, sizeof(Table) + 13);
+    if( pStat1==0 ) return;
+    pStat1->zName = (char*)&pStat1[1];
+    memcpy(pStat1->zName, "sqlite_stat1", 13);
+    pStat1->nCol = 3;
+    pStat1->iPKey = -1;
+    sqlite3VdbeAddOp4(pParse->pVdbe, OP_Noop, 0, 0, 0,(char*)pStat1,P4_DYNAMIC);
+  }
+#endif
+
+  /* Establish a read-lock on the table at the shared-cache level.
+  ** Open a read-only cursor on the table. Also allocate a cursor number
+  ** to use for scanning indexes (iIdxCur). No index cursor is opened at
+  ** this time though.  */
+  sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+  iTabCur = iTab++;
+  iIdxCur = iTab++;
+  pParse->nTab = MAX(pParse->nTab, iTab);
+  sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead);
+  sqlite3VdbeLoadString(v, regTabname, pTab->zName);
+
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    int nCol;                     /* Number of columns in pIdx. "N" */
+    int addrGotoEnd;               /* Address of "OP_Rewind iIdxCur" */
+    int addrNextRow;              /* Address of "next_row:" */
+    const char *zIdxName;         /* Name of the index */
+    int nColTest;                 /* Number of columns to test for changes */
+
+    if( pOnlyIdx && pOnlyIdx!=pIdx ) continue;
+    if( pIdx->pPartIdxWhere==0 ) needTableCnt = 0;
+    if( !HasRowid(pTab) && IsPrimaryKeyIndex(pIdx) ){
+      nCol = pIdx->nKeyCol;
+      zIdxName = pTab->zName;
+      nColTest = nCol - 1;
+    }else{
+      nCol = pIdx->nColumn;
+      zIdxName = pIdx->zName;
+      nColTest = pIdx->uniqNotNull ? pIdx->nKeyCol-1 : nCol-1;
+    }
+
+    /* Populate the register containing the index name. */
+    sqlite3VdbeLoadString(v, regIdxname, zIdxName);
+    VdbeComment((v, "Analysis for %s.%s", pTab->zName, zIdxName));
+
+    /*
+    ** Pseudo-code for loop that calls stat_push():
+    **
+    **   regChng = 0
+    **   Rewind csr
+    **   if eof(csr){
+    **      stat_init() with count = 0;
+    **      goto end_of_scan;
+    **   }
+    **   count()
+    **   stat_init()
+    **   goto chng_addr_0;
+    **
+    **  next_row:
+    **   regChng = 0
+    **   if( idx(0) != regPrev(0) ) goto chng_addr_0
+    **   regChng = 1
+    **   if( idx(1) != regPrev(1) ) goto chng_addr_1
+    **   ...
+    **   regChng = N
+    **   goto chng_addr_N
+    **
+    **  chng_addr_0:
+    **   regPrev(0) = idx(0)
+    **  chng_addr_1:
+    **   regPrev(1) = idx(1)
+    **  ...
+    **
+    **  endDistinctTest:
+    **   regRowid = idx(rowid)
+    **   stat_push(P, regChng, regRowid)
+    **   Next csr
+    **   if !eof(csr) goto next_row;
+    **
+    **  end_of_scan:
+    */
+
+    /* Make sure there are enough memory cells allocated to accommodate
+    ** the regPrev array and a trailing rowid (the rowid slot is required
+    ** when building a record to insert into the sample column of
+    ** the sqlite_stat4 table.  */
+    sqlite3TouchRegister(pParse, regPrev+nColTest);
+
+    /* Open a read-only cursor on the index being analyzed. */
+    assert( iDb==sqlite3SchemaToIndex(db, pIdx->pSchema) );
+    sqlite3VdbeAddOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb);
+    sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+    VdbeComment((v, "%s", pIdx->zName));
+
+    /* Implementation of the following:
+    **
+    **   regChng = 0
+    **   Rewind csr
+    **   if eof(csr){
+    **      stat_init() with count = 0;
+    **      goto end_of_scan;
+    **   }
+    **   count()
+    **   stat_init()
+    **   goto chng_addr_0;
+    */
+    assert( regTemp2==regStat+4 );
+    sqlite3VdbeAddOp2(v, OP_Integer, db->nAnalysisLimit, regTemp2);
+
+    /* Arguments to stat_init():
+    **    (1) the number of columns in the index including the rowid
+    **        (or for a WITHOUT ROWID table, the number of PK columns),
+    **    (2) the number of columns in the key without the rowid/pk
+    **    (3) estimated number of rows in the index. */
+    sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat+1);
+    assert( regRowid==regStat+2 );
+    sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regRowid);
+    sqlite3VdbeAddOp3(v, OP_Count, iIdxCur, regTemp,
+                      OptimizationDisabled(db, SQLITE_Stat4));
+    sqlite3VdbeAddFunctionCall(pParse, 0, regStat+1, regStat, 4,
+                               &statInitFuncdef, 0);
+    addrGotoEnd = sqlite3VdbeAddOp1(v, OP_Rewind, iIdxCur);
+    VdbeCoverage(v);
+
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regChng);
+    addrNextRow = sqlite3VdbeCurrentAddr(v);
+
+    if( nColTest>0 ){
+      int endDistinctTest = sqlite3VdbeMakeLabel(pParse);
+      int *aGotoChng;               /* Array of jump instruction addresses */
+      aGotoChng = sqlite3DbMallocRawNN(db, sizeof(int)*nColTest);
+      if( aGotoChng==0 ) continue;
+
+      /*
+      **  next_row:
+      **   regChng = 0
+      **   if( idx(0) != regPrev(0) ) goto chng_addr_0
+      **   regChng = 1
+      **   if( idx(1) != regPrev(1) ) goto chng_addr_1
+      **   ...
+      **   regChng = N
+      **   goto endDistinctTest
+      */
+      sqlite3VdbeAddOp0(v, OP_Goto);
+      addrNextRow = sqlite3VdbeCurrentAddr(v);
+      if( nColTest==1 && pIdx->nKeyCol==1 && IsUniqueIndex(pIdx) ){
+        /* For a single-column UNIQUE index, once we have found a non-NULL
+        ** row, we know that all the rest will be distinct, so skip
+        ** subsequent distinctness tests. */
+        sqlite3VdbeAddOp2(v, OP_NotNull, regPrev, endDistinctTest);
+        VdbeCoverage(v);
+      }
+      for(i=0; i<nColTest; i++){
+        char *pColl = (char*)sqlite3LocateCollSeq(pParse, pIdx->azColl[i]);
+        sqlite3VdbeAddOp2(v, OP_Integer, i, regChng);
+        sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regTemp);
+        analyzeVdbeCommentIndexWithColumnName(v,pIdx,i);
+        aGotoChng[i] =
+        sqlite3VdbeAddOp4(v, OP_Ne, regTemp, 0, regPrev+i, pColl, P4_COLLSEQ);
+        sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
+        VdbeCoverage(v);
+      }
+      sqlite3VdbeAddOp2(v, OP_Integer, nColTest, regChng);
+      sqlite3VdbeGoto(v, endDistinctTest);
+
+
+      /*
+      **  chng_addr_0:
+      **   regPrev(0) = idx(0)
+      **  chng_addr_1:
+      **   regPrev(1) = idx(1)
+      **  ...
+      */
+      sqlite3VdbeJumpHere(v, addrNextRow-1);
+      for(i=0; i<nColTest; i++){
+        sqlite3VdbeJumpHere(v, aGotoChng[i]);
+        sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regPrev+i);
+        analyzeVdbeCommentIndexWithColumnName(v,pIdx,i);
+      }
+      sqlite3VdbeResolveLabel(v, endDistinctTest);
+      sqlite3DbFree(db, aGotoChng);
+    }
+
+    /*
+    **  chng_addr_N:
+    **   regRowid = idx(rowid)            // STAT4 only
+    **   stat_push(P, regChng, regRowid)  // 3rd parameter STAT4 only
+    **   Next csr
+    **   if !eof(csr) goto next_row;
+    */
+#ifdef SQLITE_ENABLE_STAT4
+    if( OptimizationEnabled(db, SQLITE_Stat4) ){
+      assert( regRowid==(regStat+2) );
+      if( HasRowid(pTab) ){
+        sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, regRowid);
+      }else{
+        Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable);
+        int j, k, regKey;
+        regKey = sqlite3GetTempRange(pParse, pPk->nKeyCol);
+        for(j=0; j<pPk->nKeyCol; j++){
+          k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[j]);
+          assert( k>=0 && k<pIdx->nColumn );
+          sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, regKey+j);
+          analyzeVdbeCommentIndexWithColumnName(v,pIdx,k);
+        }
+        sqlite3VdbeAddOp3(v, OP_MakeRecord, regKey, pPk->nKeyCol, regRowid);
+        sqlite3ReleaseTempRange(pParse, regKey, pPk->nKeyCol);
+      }
+    }
+#endif
+    assert( regChng==(regStat+1) );
+    {
+      sqlite3VdbeAddFunctionCall(pParse, 1, regStat, regTemp, 2+IsStat4,
+                                 &statPushFuncdef, 0);
+      if( db->nAnalysisLimit ){
+        int j1, j2, j3;
+        j1 = sqlite3VdbeAddOp1(v, OP_IsNull, regTemp); VdbeCoverage(v);
+        j2 = sqlite3VdbeAddOp1(v, OP_If, regTemp); VdbeCoverage(v);
+        j3 = sqlite3VdbeAddOp4Int(v, OP_SeekGT, iIdxCur, 0, regPrev, 1);
+        VdbeCoverage(v);
+        sqlite3VdbeJumpHere(v, j1);
+        sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);
+        sqlite3VdbeJumpHere(v, j2);
+        sqlite3VdbeJumpHere(v, j3);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);
+      }
+    }
+
+    /* Add the entry to the stat1 table. */
+    if( pIdx->pPartIdxWhere ){
+      /* Partial indexes might get a zero-entry in sqlite_stat1.  But
+      ** an empty table is omitted from sqlite_stat1. */
+      sqlite3VdbeJumpHere(v, addrGotoEnd);
+      addrGotoEnd = 0;
+    }
+    callStatGet(pParse, regStat, STAT_GET_STAT1, regStat1);
+    assert( "BBB"[0]==SQLITE_AFF_TEXT );
+    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "BBB", 0);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
+    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regTemp, regNewRowid);
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    sqlite3VdbeChangeP4(v, -1, (char*)pStat1, P4_TABLE);
+#endif
+    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+
+    /* Add the entries to the stat4 table. */
+#ifdef SQLITE_ENABLE_STAT4
+    if( OptimizationEnabled(db, SQLITE_Stat4) && db->nAnalysisLimit==0 ){
+      int regEq = regStat1;
+      int regLt = regStat1+1;
+      int regDLt = regStat1+2;
+      int regSample = regStat1+3;
+      int regCol = regStat1+4;
+      int regSampleRowid = regCol + nCol;
+      int addrNext;
+      int addrIsNull;
+      u8 seekOp = HasRowid(pTab) ? OP_NotExists : OP_NotFound;
+
+      /* No STAT4 data is generated if the number of rows is zero */
+      if( addrGotoEnd==0 ){
+        sqlite3VdbeAddOp2(v, OP_Cast, regStat1, SQLITE_AFF_INTEGER);
+        addrGotoEnd = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1);
+        VdbeCoverage(v);
+      }
+
+      if( doOnce ){
+        int mxCol = nCol;
+        Index *pX;
+
+        /* Compute the maximum number of columns in any index */
+        for(pX=pTab->pIndex; pX; pX=pX->pNext){
+          int nColX;                     /* Number of columns in pX */
+          if( !HasRowid(pTab) && IsPrimaryKeyIndex(pX) ){
+            nColX = pX->nKeyCol;
+          }else{
+            nColX = pX->nColumn;
+          }
+          if( nColX>mxCol ) mxCol = nColX;
+        }
+
+        /* Allocate space to compute results for the largest index */
+        sqlite3TouchRegister(pParse, regCol+mxCol);
+        doOnce = 0;
+#ifdef SQLITE_DEBUG
+        /* Verify that the call to sqlite3ClearTempRegCache() below
+        ** really is needed.
+        ** https://sqlite.org/forum/forumpost/83cb4a95a0 (2023-03-25)
+        */
+        testcase( !sqlite3NoTempsInRange(pParse, regEq, regCol+mxCol) );
+#endif
+        sqlite3ClearTempRegCache(pParse);  /* tag-20230325-1 */
+        assert( sqlite3NoTempsInRange(pParse, regEq, regCol+mxCol) );
+      }
+      assert( sqlite3NoTempsInRange(pParse, regEq, regCol+nCol) );
+
+      addrNext = sqlite3VdbeCurrentAddr(v);
+      callStatGet(pParse, regStat, STAT_GET_ROWID, regSampleRowid);
+      addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, regSampleRowid);
+      VdbeCoverage(v);
+      callStatGet(pParse, regStat, STAT_GET_NEQ, regEq);
+      callStatGet(pParse, regStat, STAT_GET_NLT, regLt);
+      callStatGet(pParse, regStat, STAT_GET_NDLT, regDLt);
+      sqlite3VdbeAddOp4Int(v, seekOp, iTabCur, addrNext, regSampleRowid, 0);
+      VdbeCoverage(v);
+      for(i=0; i<nCol; i++){
+        sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iTabCur, i, regCol+i);
+      }
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regCol, nCol, regSample);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regTabname, 6, regTemp);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur+1, regNewRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, iStatCur+1, regTemp, regNewRowid);
+      sqlite3VdbeAddOp2(v, OP_Goto, 1, addrNext); /* P1==1 for end-of-loop */
+      sqlite3VdbeJumpHere(v, addrIsNull);
+    }
+#endif /* SQLITE_ENABLE_STAT4 */
+
+    /* End of analysis */
+    if( addrGotoEnd ) sqlite3VdbeJumpHere(v, addrGotoEnd);
+  }
+
+
+  /* Create a single sqlite_stat1 entry containing NULL as the index
+  ** name and the row count as the content.
+  */
+  if( pOnlyIdx==0 && needTableCnt ){
+    VdbeComment((v, "%s", pTab->zName));
+    sqlite3VdbeAddOp2(v, OP_Count, iTabCur, regStat1);
+    jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1); VdbeCoverage(v);
+    sqlite3VdbeAddOp2(v, OP_Null, 0, regIdxname);
+    assert( "BBB"[0]==SQLITE_AFF_TEXT );
+    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "BBB", 0);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
+    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regTemp, regNewRowid);
+    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    sqlite3VdbeChangeP4(v, -1, (char*)pStat1, P4_TABLE);
+#endif
+    sqlite3VdbeJumpHere(v, jZeroRows);
+  }
+}
+
+
+/*
+** Generate code that will cause the most recent index analysis to
+** be loaded into internal hash tables where is can be used.
+*/
+static void loadAnalysis(Parse *pParse, int iDb){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp1(v, OP_LoadAnalysis, iDb);
+  }
+}
+
+/*
+** Generate code that will do an analysis of an entire database
+*/
+static void analyzeDatabase(Parse *pParse, int iDb){
+  sqlite3 *db = pParse->db;
+  Schema *pSchema = db->aDb[iDb].pSchema;    /* Schema of database iDb */
+  HashElem *k;
+  int iStatCur;
+  int iMem;
+  int iTab;
+
+  sqlite3BeginWriteOperation(pParse, 0, iDb);
+  iStatCur = pParse->nTab;
+  pParse->nTab += 3;
+  openStatTable(pParse, iDb, iStatCur, 0, 0);
+  iMem = pParse->nMem+1;
+  iTab = pParse->nTab;
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
+    Table *pTab = (Table*)sqliteHashData(k);
+    analyzeOneTable(pParse, pTab, 0, iStatCur, iMem, iTab);
+#ifdef SQLITE_ENABLE_STAT4
+    iMem = sqlite3FirstAvailableRegister(pParse, iMem);
+#else
+    assert( iMem==sqlite3FirstAvailableRegister(pParse,iMem) );
+#endif
+  }
+  loadAnalysis(pParse, iDb);
+}
+
+/*
+** Generate code that will do an analysis of a single table in
+** a database.  If pOnlyIdx is not NULL then it is a single index
+** in pTab that should be analyzed.
+*/
+static void analyzeTable(Parse *pParse, Table *pTab, Index *pOnlyIdx){
+  int iDb;
+  int iStatCur;
+
+  assert( pTab!=0 );
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  sqlite3BeginWriteOperation(pParse, 0, iDb);
+  iStatCur = pParse->nTab;
+  pParse->nTab += 3;
+  if( pOnlyIdx ){
+    openStatTable(pParse, iDb, iStatCur, pOnlyIdx->zName, "idx");
+  }else{
+    openStatTable(pParse, iDb, iStatCur, pTab->zName, "tbl");
+  }
+  analyzeOneTable(pParse, pTab, pOnlyIdx, iStatCur,pParse->nMem+1,pParse->nTab);
+  loadAnalysis(pParse, iDb);
+}
+
+/*
+** Generate code for the ANALYZE command.  The parser calls this routine
+** when it recognizes an ANALYZE command.
+**
+**        ANALYZE                            -- 1
+**        ANALYZE  <database>                -- 2
+**        ANALYZE  ?<database>.?<tablename>  -- 3
+**
+** Form 1 causes all indices in all attached databases to be analyzed.
+** Form 2 analyzes all indices the single database named.
+** Form 3 analyzes all indices associated with the named table.
+*/
+SQLITE_PRIVATE void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){
+  sqlite3 *db = pParse->db;
+  int iDb;
+  int i;
+  char *z, *zDb;
+  Table *pTab;
+  Index *pIdx;
+  Token *pTableName;
+  Vdbe *v;
+
+  /* Read the database schema. If an error occurs, leave an error message
+  ** and code in pParse and return NULL. */
+  assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    return;
+  }
+
+  assert( pName2!=0 || pName1==0 );
+  if( pName1==0 ){
+    /* Form 1:  Analyze everything */
+    for(i=0; i<db->nDb; i++){
+      if( i==1 ) continue;  /* Do not analyze the TEMP database */
+      analyzeDatabase(pParse, i);
+    }
+  }else if( pName2->n==0 && (iDb = sqlite3FindDb(db, pName1))>=0 ){
+    /* Analyze the schema named as the argument */
+    analyzeDatabase(pParse, iDb);
+  }else{
+    /* Form 3: Analyze the table or index named as an argument */
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pTableName);
+    if( iDb>=0 ){
+      zDb = pName2->n ? db->aDb[iDb].zDbSName : 0;
+      z = sqlite3NameFromToken(db, pTableName);
+      if( z ){
+        if( (pIdx = sqlite3FindIndex(db, z, zDb))!=0 ){
+          analyzeTable(pParse, pIdx->pTable, pIdx);
+        }else if( (pTab = sqlite3LocateTable(pParse, 0, z, zDb))!=0 ){
+          analyzeTable(pParse, pTab, 0);
+        }
+        sqlite3DbFree(db, z);
+      }
+    }
+  }
+  if( db->nSqlExec==0 && (v = sqlite3GetVdbe(pParse))!=0 ){
+    sqlite3VdbeAddOp0(v, OP_Expire);
+  }
+}
+
+/*
+** Used to pass information from the analyzer reader through to the
+** callback routine.
+*/
+typedef struct analysisInfo analysisInfo;
+struct analysisInfo {
+  sqlite3 *db;
+  const char *zDatabase;
+};
+
+/*
+** The first argument points to a nul-terminated string containing a
+** list of space separated integers. Read the first nOut of these into
+** the array aOut[].
+*/
+static void decodeIntArray(
+  char *zIntArray,       /* String containing int array to decode */
+  int nOut,              /* Number of slots in aOut[] */
+  tRowcnt *aOut,         /* Store integers here */
+  LogEst *aLog,          /* Or, if aOut==0, here */
+  Index *pIndex          /* Handle extra flags for this index, if not NULL */
+){
+  char *z = zIntArray;
+  int c;
+  int i;
+  tRowcnt v;
+
+#ifdef SQLITE_ENABLE_STAT4
+  if( z==0 ) z = "";
+#else
+  assert( z!=0 );
+#endif
+  for(i=0; *z && i<nOut; i++){
+    v = 0;
+    while( (c=z[0])>='0' && c<='9' ){
+      v = v*10 + c - '0';
+      z++;
+    }
+#ifdef SQLITE_ENABLE_STAT4
+    if( aOut ) aOut[i] = v;
+    if( aLog ) aLog[i] = sqlite3LogEst(v);
+#else
+    assert( aOut==0 );
+    UNUSED_PARAMETER(aOut);
+    assert( aLog!=0 );
+    aLog[i] = sqlite3LogEst(v);
+#endif
+    if( *z==' ' ) z++;
+  }
+#ifndef SQLITE_ENABLE_STAT4
+  assert( pIndex!=0 ); {
+#else
+  if( pIndex ){
+#endif
+    pIndex->bUnordered = 0;
+    pIndex->noSkipScan = 0;
+    while( z[0] ){
+      if( sqlite3_strglob("unordered*", z)==0 ){
+        pIndex->bUnordered = 1;
+      }else if( sqlite3_strglob("sz=[0-9]*", z)==0 ){
+        int sz = sqlite3Atoi(z+3);
+        if( sz<2 ) sz = 2;
+        pIndex->szIdxRow = sqlite3LogEst(sz);
+      }else if( sqlite3_strglob("noskipscan*", z)==0 ){
+        pIndex->noSkipScan = 1;
+      }
+#ifdef SQLITE_ENABLE_COSTMULT
+      else if( sqlite3_strglob("costmult=[0-9]*",z)==0 ){
+        pIndex->pTable->costMult = sqlite3LogEst(sqlite3Atoi(z+9));
+      }
+#endif
+      while( z[0]!=0 && z[0]!=' ' ) z++;
+      while( z[0]==' ' ) z++;
+    }
+
+    /* Set the bLowQual flag if the peak number of rows obtained
+    ** from a full equality match is so large that a full table scan
+    ** seems likely to be faster than using the index.
+    */
+    if( aLog[0] > 66              /* Index has more than 100 rows */
+     && aLog[0] <= aLog[nOut-1]   /* And only a single value seen */
+    ){
+      pIndex->bLowQual = 1;
+    }
+  }
+}
+
+/*
+** This callback is invoked once for each index when reading the
+** sqlite_stat1 table.
+**
+**     argv[0] = name of the table
+**     argv[1] = name of the index (might be NULL)
+**     argv[2] = results of analysis - on integer for each column
+**
+** Entries for which argv[1]==NULL simply record the number of rows in
+** the table.
+*/
+static int analysisLoader(void *pData, int argc, char **argv, char **NotUsed){
+  analysisInfo *pInfo = (analysisInfo*)pData;
+  Index *pIndex;
+  Table *pTable;
+  const char *z;
+
+  assert( argc==3 );
+  UNUSED_PARAMETER2(NotUsed, argc);
+
+  if( argv==0 || argv[0]==0 || argv[2]==0 ){
+    return 0;
+  }
+  pTable = sqlite3FindTable(pInfo->db, argv[0], pInfo->zDatabase);
+  if( pTable==0 ){
+    return 0;
+  }
+  if( argv[1]==0 ){
+    pIndex = 0;
+  }else if( sqlite3_stricmp(argv[0],argv[1])==0 ){
+    pIndex = sqlite3PrimaryKeyIndex(pTable);
+  }else{
+    pIndex = sqlite3FindIndex(pInfo->db, argv[1], pInfo->zDatabase);
+  }
+  z = argv[2];
+
+  if( pIndex ){
+    tRowcnt *aiRowEst = 0;
+    int nCol = pIndex->nKeyCol+1;
+#ifdef SQLITE_ENABLE_STAT4
+    /* Index.aiRowEst may already be set here if there are duplicate
+    ** sqlite_stat1 entries for this index. In that case just clobber
+    ** the old data with the new instead of allocating a new array.  */
+    if( pIndex->aiRowEst==0 ){
+      pIndex->aiRowEst = (tRowcnt*)sqlite3MallocZero(sizeof(tRowcnt) * nCol);
+      if( pIndex->aiRowEst==0 ) sqlite3OomFault(pInfo->db);
+    }
+    aiRowEst = pIndex->aiRowEst;
+#endif
+    pIndex->bUnordered = 0;
+    decodeIntArray((char*)z, nCol, aiRowEst, pIndex->aiRowLogEst, pIndex);
+    pIndex->hasStat1 = 1;
+    if( pIndex->pPartIdxWhere==0 ){
+      pTable->nRowLogEst = pIndex->aiRowLogEst[0];
+      pTable->tabFlags |= TF_HasStat1;
+    }
+  }else{
+    Index fakeIdx;
+    fakeIdx.szIdxRow = pTable->szTabRow;
+#ifdef SQLITE_ENABLE_COSTMULT
+    fakeIdx.pTable = pTable;
+#endif
+    decodeIntArray((char*)z, 1, 0, &pTable->nRowLogEst, &fakeIdx);
+    pTable->szTabRow = fakeIdx.szIdxRow;
+    pTable->tabFlags |= TF_HasStat1;
+  }
+
+  return 0;
+}
+
+/*
+** If the Index.aSample variable is not NULL, delete the aSample[] array
+** and its contents.
+*/
+SQLITE_PRIVATE void sqlite3DeleteIndexSamples(sqlite3 *db, Index *pIdx){
+  assert( db!=0 );
+  assert( pIdx!=0 );
+#ifdef SQLITE_ENABLE_STAT4
+  if( pIdx->aSample ){
+    int j;
+    for(j=0; j<pIdx->nSample; j++){
+      IndexSample *p = &pIdx->aSample[j];
+      sqlite3DbFree(db, p->p);
+    }
+    sqlite3DbFree(db, pIdx->aSample);
+  }
+  if( db->pnBytesFreed==0 ){
+    pIdx->nSample = 0;
+    pIdx->aSample = 0;
+  }
+#else
+  UNUSED_PARAMETER(db);
+  UNUSED_PARAMETER(pIdx);
+#endif /* SQLITE_ENABLE_STAT4 */
+}
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Populate the pIdx->aAvgEq[] array based on the samples currently
+** stored in pIdx->aSample[].
+*/
+static void initAvgEq(Index *pIdx){
+  if( pIdx ){
+    IndexSample *aSample = pIdx->aSample;
+    IndexSample *pFinal = &aSample[pIdx->nSample-1];
+    int iCol;
+    int nCol = 1;
+    if( pIdx->nSampleCol>1 ){
+      /* If this is stat4 data, then calculate aAvgEq[] values for all
+      ** sample columns except the last. The last is always set to 1, as
+      ** once the trailing PK fields are considered all index keys are
+      ** unique.  */
+      nCol = pIdx->nSampleCol-1;
+      pIdx->aAvgEq[nCol] = 1;
+    }
+    for(iCol=0; iCol<nCol; iCol++){
+      int nSample = pIdx->nSample;
+      int i;                    /* Used to iterate through samples */
+      tRowcnt sumEq = 0;        /* Sum of the nEq values */
+      tRowcnt avgEq = 0;
+      tRowcnt nRow;             /* Number of rows in index */
+      i64 nSum100 = 0;          /* Number of terms contributing to sumEq */
+      i64 nDist100;             /* Number of distinct values in index */
+
+      if( !pIdx->aiRowEst || iCol>=pIdx->nKeyCol || pIdx->aiRowEst[iCol+1]==0 ){
+        nRow = pFinal->anLt[iCol];
+        nDist100 = (i64)100 * pFinal->anDLt[iCol];
+        nSample--;
+      }else{
+        nRow = pIdx->aiRowEst[0];
+        nDist100 = ((i64)100 * pIdx->aiRowEst[0]) / pIdx->aiRowEst[iCol+1];
+      }
+      pIdx->nRowEst0 = nRow;
+
+      /* Set nSum to the number of distinct (iCol+1) field prefixes that
+      ** occur in the stat4 table for this index. Set sumEq to the sum of
+      ** the nEq values for column iCol for the same set (adding the value
+      ** only once where there exist duplicate prefixes).  */
+      for(i=0; i<nSample; i++){
+        if( i==(pIdx->nSample-1)
+         || aSample[i].anDLt[iCol]!=aSample[i+1].anDLt[iCol]
+        ){
+          sumEq += aSample[i].anEq[iCol];
+          nSum100 += 100;
+        }
+      }
+
+      if( nDist100>nSum100 && sumEq<nRow ){
+        avgEq = ((i64)100 * (nRow - sumEq))/(nDist100 - nSum100);
+      }
+      if( avgEq==0 ) avgEq = 1;
+      pIdx->aAvgEq[iCol] = avgEq;
+    }
+  }
+}
+
+/*
+** Look up an index by name.  Or, if the name of a WITHOUT ROWID table
+** is supplied instead, find the PRIMARY KEY index for that table.
+*/
+static Index *findIndexOrPrimaryKey(
+  sqlite3 *db,
+  const char *zName,
+  const char *zDb
+){
+  Index *pIdx = sqlite3FindIndex(db, zName, zDb);
+  if( pIdx==0 ){
+    Table *pTab = sqlite3FindTable(db, zName, zDb);
+    if( pTab && !HasRowid(pTab) ) pIdx = sqlite3PrimaryKeyIndex(pTab);
+  }
+  return pIdx;
+}
+
+/*
+** Load the content from either the sqlite_stat4
+** into the relevant Index.aSample[] arrays.
+**
+** Arguments zSql1 and zSql2 must point to SQL statements that return
+** data equivalent to the following:
+**
+**    zSql1: SELECT idx,count(*) FROM %Q.sqlite_stat4 GROUP BY idx
+**    zSql2: SELECT idx,neq,nlt,ndlt,sample FROM %Q.sqlite_stat4
+**
+** where %Q is replaced with the database name before the SQL is executed.
+*/
+static int loadStatTbl(
+  sqlite3 *db,                  /* Database handle */
+  const char *zSql1,            /* SQL statement 1 (see above) */
+  const char *zSql2,            /* SQL statement 2 (see above) */
+  const char *zDb               /* Database name (e.g. "main") */
+){
+  int rc;                       /* Result codes from subroutines */
+  sqlite3_stmt *pStmt = 0;      /* An SQL statement being run */
+  char *zSql;                   /* Text of the SQL statement */
+  Index *pPrevIdx = 0;          /* Previous index in the loop */
+  IndexSample *pSample;         /* A slot in pIdx->aSample[] */
+
+  assert( db->lookaside.bDisable );
+  zSql = sqlite3MPrintf(db, zSql1, zDb);
+  if( !zSql ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+  sqlite3DbFree(db, zSql);
+  if( rc ) return rc;
+
+  while( sqlite3_step(pStmt)==SQLITE_ROW ){
+    int nIdxCol = 1;              /* Number of columns in stat4 records */
+
+    char *zIndex;    /* Index name */
+    Index *pIdx;     /* Pointer to the index object */
+    int nSample;     /* Number of samples */
+    i64 nByte;       /* Bytes of space required */
+    i64 i;           /* Bytes of space required */
+    tRowcnt *pSpace; /* Available allocated memory space */
+    u8 *pPtr;        /* Available memory as a u8 for easier manipulation */
+
+    zIndex = (char *)sqlite3_column_text(pStmt, 0);
+    if( zIndex==0 ) continue;
+    nSample = sqlite3_column_int(pStmt, 1);
+    pIdx = findIndexOrPrimaryKey(db, zIndex, zDb);
+    assert( pIdx==0 || pIdx->nSample==0 );
+    if( pIdx==0 ) continue;
+    if( pIdx->aSample!=0 ){
+      /* The same index appears in sqlite_stat4 under multiple names */
+      continue;
+    }
+    assert( !HasRowid(pIdx->pTable) || pIdx->nColumn==pIdx->nKeyCol+1 );
+    if( !HasRowid(pIdx->pTable) && IsPrimaryKeyIndex(pIdx) ){
+      nIdxCol = pIdx->nKeyCol;
+    }else{
+      nIdxCol = pIdx->nColumn;
+    }
+    pIdx->nSampleCol = nIdxCol;
+    pIdx->mxSample = nSample;
+    nByte = ROUND8(sizeof(IndexSample) * nSample);
+    nByte += sizeof(tRowcnt) * nIdxCol * 3 * nSample;
+    nByte += nIdxCol * sizeof(tRowcnt);     /* Space for Index.aAvgEq[] */
+
+    pIdx->aSample = sqlite3DbMallocZero(db, nByte);
+    if( pIdx->aSample==0 ){
+      sqlite3_finalize(pStmt);
+      return SQLITE_NOMEM_BKPT;
+    }
+    pPtr = (u8*)pIdx->aSample;
+    pPtr += ROUND8(nSample*sizeof(pIdx->aSample[0]));
+    pSpace = (tRowcnt*)pPtr;
+    assert( EIGHT_BYTE_ALIGNMENT( pSpace ) );
+    pIdx->aAvgEq = pSpace; pSpace += nIdxCol;
+    pIdx->pTable->tabFlags |= TF_HasStat4;
+    for(i=0; i<nSample; i++){
+      pIdx->aSample[i].anEq = pSpace; pSpace += nIdxCol;
+      pIdx->aSample[i].anLt = pSpace; pSpace += nIdxCol;
+      pIdx->aSample[i].anDLt = pSpace; pSpace += nIdxCol;
+    }
+    assert( ((u8*)pSpace)-nByte==(u8*)(pIdx->aSample) );
+  }
+  rc = sqlite3_finalize(pStmt);
+  if( rc ) return rc;
+
+  zSql = sqlite3MPrintf(db, zSql2, zDb);
+  if( !zSql ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+  sqlite3DbFree(db, zSql);
+  if( rc ) return rc;
+
+  while( sqlite3_step(pStmt)==SQLITE_ROW ){
+    char *zIndex;                 /* Index name */
+    Index *pIdx;                  /* Pointer to the index object */
+    int nCol = 1;                 /* Number of columns in index */
+
+    zIndex = (char *)sqlite3_column_text(pStmt, 0);
+    if( zIndex==0 ) continue;
+    pIdx = findIndexOrPrimaryKey(db, zIndex, zDb);
+    if( pIdx==0 ) continue;
+    if( pIdx->nSample>=pIdx->mxSample ){
+      /* Too many slots used because the same index appears in
+      ** sqlite_stat4 using multiple names */
+      continue;
+    }
+    /* This next condition is true if data has already been loaded from
+    ** the sqlite_stat4 table. */
+    nCol = pIdx->nSampleCol;
+    if( pIdx!=pPrevIdx ){
+      initAvgEq(pPrevIdx);
+      pPrevIdx = pIdx;
+    }
+    pSample = &pIdx->aSample[pIdx->nSample];
+    decodeIntArray((char*)sqlite3_column_text(pStmt,1),nCol,pSample->anEq,0,0);
+    decodeIntArray((char*)sqlite3_column_text(pStmt,2),nCol,pSample->anLt,0,0);
+    decodeIntArray((char*)sqlite3_column_text(pStmt,3),nCol,pSample->anDLt,0,0);
+
+    /* Take a copy of the sample. Add 8 extra 0x00 bytes the end of the buffer.
+    ** This is in case the sample record is corrupted. In that case, the
+    ** sqlite3VdbeRecordCompare() may read up to two varints past the
+    ** end of the allocated buffer before it realizes it is dealing with
+    ** a corrupt record.  Or it might try to read a large integer from the
+    ** buffer.  In any case, eight 0x00 bytes prevents this from causing
+    ** a buffer overread.  */
+    pSample->n = sqlite3_column_bytes(pStmt, 4);
+    pSample->p = sqlite3DbMallocZero(db, pSample->n + 8);
+    if( pSample->p==0 ){
+      sqlite3_finalize(pStmt);
+      return SQLITE_NOMEM_BKPT;
+    }
+    if( pSample->n ){
+      memcpy(pSample->p, sqlite3_column_blob(pStmt, 4), pSample->n);
+    }
+    pIdx->nSample++;
+  }
+  rc = sqlite3_finalize(pStmt);
+  if( rc==SQLITE_OK ) initAvgEq(pPrevIdx);
+  return rc;
+}
+
+/*
+** Load content from the sqlite_stat4 table into
+** the Index.aSample[] arrays of all indices.
+*/
+static int loadStat4(sqlite3 *db, const char *zDb){
+  int rc = SQLITE_OK;             /* Result codes from subroutines */
+  const Table *pStat4;
+
+  assert( db->lookaside.bDisable );
+  if( OptimizationEnabled(db, SQLITE_Stat4)
+   && (pStat4 = sqlite3FindTable(db, "sqlite_stat4", zDb))!=0
+   && IsOrdinaryTable(pStat4)
+  ){
+    rc = loadStatTbl(db,
+      "SELECT idx,count(*) FROM %Q.sqlite_stat4 GROUP BY idx COLLATE nocase",
+      "SELECT idx,neq,nlt,ndlt,sample FROM %Q.sqlite_stat4",
+      zDb
+    );
+  }
+  return rc;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+/*
+** Load the content of the sqlite_stat1 and sqlite_stat4 tables. The
+** contents of sqlite_stat1 are used to populate the Index.aiRowEst[]
+** arrays. The contents of sqlite_stat4 are used to populate the
+** Index.aSample[] arrays.
+**
+** If the sqlite_stat1 table is not present in the database, SQLITE_ERROR
+** is returned. In this case, even if SQLITE_ENABLE_STAT4 was defined
+** during compilation and the sqlite_stat4 table is present, no data is
+** read from it.
+**
+** If SQLITE_ENABLE_STAT4 was defined during compilation and the
+** sqlite_stat4 table is not present in the database, SQLITE_ERROR is
+** returned. However, in this case, data is read from the sqlite_stat1
+** table (if it is present) before returning.
+**
+** If an OOM error occurs, this function always sets db->mallocFailed.
+** This means if the caller does not care about other errors, the return
+** code may be ignored.
+*/
+SQLITE_PRIVATE int sqlite3AnalysisLoad(sqlite3 *db, int iDb){
+  analysisInfo sInfo;
+  HashElem *i;
+  char *zSql;
+  int rc = SQLITE_OK;
+  Schema *pSchema = db->aDb[iDb].pSchema;
+  const Table *pStat1;
+
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( db->aDb[iDb].pBt!=0 );
+
+  /* Clear any prior statistics */
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  for(i=sqliteHashFirst(&pSchema->tblHash); i; i=sqliteHashNext(i)){
+    Table *pTab = sqliteHashData(i);
+    pTab->tabFlags &= ~TF_HasStat1;
+  }
+  for(i=sqliteHashFirst(&pSchema->idxHash); i; i=sqliteHashNext(i)){
+    Index *pIdx = sqliteHashData(i);
+    pIdx->hasStat1 = 0;
+#ifdef SQLITE_ENABLE_STAT4
+    sqlite3DeleteIndexSamples(db, pIdx);
+    pIdx->aSample = 0;
+#endif
+  }
+
+  /* Load new statistics out of the sqlite_stat1 table */
+  sInfo.db = db;
+  sInfo.zDatabase = db->aDb[iDb].zDbSName;
+  if( (pStat1 = sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase))
+   && IsOrdinaryTable(pStat1)
+  ){
+    zSql = sqlite3MPrintf(db,
+        "SELECT tbl,idx,stat FROM %Q.sqlite_stat1", sInfo.zDatabase);
+    if( zSql==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0);
+      sqlite3DbFree(db, zSql);
+    }
+  }
+
+  /* Set appropriate defaults on all indexes not in the sqlite_stat1 table */
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  for(i=sqliteHashFirst(&pSchema->idxHash); i; i=sqliteHashNext(i)){
+    Index *pIdx = sqliteHashData(i);
+    if( !pIdx->hasStat1 ) sqlite3DefaultRowEst(pIdx);
+  }
+
+  /* Load the statistics from the sqlite_stat4 table. */
+#ifdef SQLITE_ENABLE_STAT4
+  if( rc==SQLITE_OK ){
+    DisableLookaside;
+    rc = loadStat4(db, sInfo.zDatabase);
+    EnableLookaside;
+  }
+  for(i=sqliteHashFirst(&pSchema->idxHash); i; i=sqliteHashNext(i)){
+    Index *pIdx = sqliteHashData(i);
+    sqlite3_free(pIdx->aiRowEst);
+    pIdx->aiRowEst = 0;
+  }
+#endif
+
+  if( rc==SQLITE_NOMEM ){
+    sqlite3OomFault(db);
+  }
+  return rc;
+}
+
+
+#endif /* SQLITE_OMIT_ANALYZE */
+
+/************** End of analyze.c *********************************************/
+/************** Begin file attach.c ******************************************/
+/*
+** 2003 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the ATTACH and DETACH commands.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_ATTACH
+/*
+** Resolve an expression that was part of an ATTACH or DETACH statement. This
+** is slightly different from resolving a normal SQL expression, because simple
+** identifiers are treated as strings, not possible column names or aliases.
+**
+** i.e. if the parser sees:
+**
+**     ATTACH DATABASE abc AS def
+**
+** it treats the two expressions as literal strings 'abc' and 'def' instead of
+** looking for columns of the same name.
+**
+** This only applies to the root node of pExpr, so the statement:
+**
+**     ATTACH DATABASE abc||def AS 'db2'
+**
+** will fail because neither abc or def can be resolved.
+*/
+static int resolveAttachExpr(NameContext *pName, Expr *pExpr)
+{
+  int rc = SQLITE_OK;
+  if( pExpr ){
+    if( pExpr->op!=TK_ID ){
+      rc = sqlite3ResolveExprNames(pName, pExpr);
+    }else{
+      pExpr->op = TK_STRING;
+    }
+  }
+  return rc;
+}
+
+/*
+** Return true if zName points to a name that may be used to refer to
+** database iDb attached to handle db.
+*/
+SQLITE_PRIVATE int sqlite3DbIsNamed(sqlite3 *db, int iDb, const char *zName){
+  return (
+      sqlite3StrICmp(db->aDb[iDb].zDbSName, zName)==0
+   || (iDb==0 && sqlite3StrICmp("main", zName)==0)
+  );
+}
+
+/*
+** An SQL user-function registered to do the work of an ATTACH statement. The
+** three arguments to the function come directly from an attach statement:
+**
+**     ATTACH DATABASE x AS y KEY z
+**
+**     SELECT sqlite_attach(x, y, z)
+**
+** If the optional "KEY z" syntax is omitted, an SQL NULL is passed as the
+** third argument.
+**
+** If the db->init.reopenMemdb flags is set, then instead of attaching a
+** new database, close the database on db->init.iDb and reopen it as an
+** empty MemDB.
+*/
+static void attachFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  int i;
+  int rc = 0;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  const char *zName;
+  const char *zFile;
+  char *zPath = 0;
+  char *zErr = 0;
+  unsigned int flags;
+  Db *aNew;                 /* New array of Db pointers */
+  Db *pNew = 0;             /* Db object for the newly attached database */
+  char *zErrDyn = 0;
+  sqlite3_vfs *pVfs;
+
+  UNUSED_PARAMETER(NotUsed);
+  zFile = (const char *)sqlite3_value_text(argv[0]);
+  zName = (const char *)sqlite3_value_text(argv[1]);
+  if( zFile==0 ) zFile = "";
+  if( zName==0 ) zName = "";
+
+#ifndef SQLITE_OMIT_DESERIALIZE
+# define REOPEN_AS_MEMDB(db)  (db->init.reopenMemdb)
+#else
+# define REOPEN_AS_MEMDB(db)  (0)
+#endif
+
+  if( REOPEN_AS_MEMDB(db) ){
+    /* This is not a real ATTACH.  Instead, this routine is being called
+    ** from sqlite3_deserialize() to close database db->init.iDb and
+    ** reopen it as a MemDB */
+    Btree *pNewBt = 0;
+    pVfs = sqlite3_vfs_find("memdb");
+    if( pVfs==0 ) return;
+    rc = sqlite3BtreeOpen(pVfs, "x\0", db, &pNewBt, 0, SQLITE_OPEN_MAIN_DB);
+    if( rc==SQLITE_OK ){
+      Schema *pNewSchema = sqlite3SchemaGet(db, pNewBt);
+      if( pNewSchema ){
+        /* Both the Btree and the new Schema were allocated successfully.
+        ** Close the old db and update the aDb[] slot with the new memdb
+        ** values.  */
+        pNew = &db->aDb[db->init.iDb];
+        if( ALWAYS(pNew->pBt) ) sqlite3BtreeClose(pNew->pBt);
+        pNew->pBt = pNewBt;
+        pNew->pSchema = pNewSchema;
+      }else{
+        sqlite3BtreeClose(pNewBt);
+        rc = SQLITE_NOMEM;
+      }
+    }
+    if( rc ) goto attach_error;
+  }else{
+    /* This is a real ATTACH
+    **
+    ** Check for the following errors:
+    **
+    **     * Too many attached databases,
+    **     * Transaction currently open
+    **     * Specified database name already being used.
+    */
+    if( db->nDb>=db->aLimit[SQLITE_LIMIT_ATTACHED]+2 ){
+      zErrDyn = sqlite3MPrintf(db, "too many attached databases - max %d",
+        db->aLimit[SQLITE_LIMIT_ATTACHED]
+      );
+      goto attach_error;
+    }
+    for(i=0; i<db->nDb; i++){
+      assert( zName );
+      if( sqlite3DbIsNamed(db, i, zName) ){
+        zErrDyn = sqlite3MPrintf(db, "database %s is already in use", zName);
+        goto attach_error;
+      }
+    }
+
+    /* Allocate the new entry in the db->aDb[] array and initialize the schema
+    ** hash tables.
+    */
+    if( db->aDb==db->aDbStatic ){
+      aNew = sqlite3DbMallocRawNN(db, sizeof(db->aDb[0])*3 );
+      if( aNew==0 ) return;
+      memcpy(aNew, db->aDb, sizeof(db->aDb[0])*2);
+    }else{
+      aNew = sqlite3DbRealloc(db, db->aDb, sizeof(db->aDb[0])*(db->nDb+1) );
+      if( aNew==0 ) return;
+    }
+    db->aDb = aNew;
+    pNew = &db->aDb[db->nDb];
+    memset(pNew, 0, sizeof(*pNew));
+
+    /* Open the database file. If the btree is successfully opened, use
+    ** it to obtain the database schema. At this point the schema may
+    ** or may not be initialized.
+    */
+    flags = db->openFlags;
+    rc = sqlite3ParseUri(db->pVfs->zName, zFile, &flags, &pVfs, &zPath, &zErr);
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
+      sqlite3_result_error(context, zErr, -1);
+      sqlite3_free(zErr);
+      return;
+    }
+    if( (db->flags & SQLITE_AttachWrite)==0 ){
+      flags &= ~(SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE);
+      flags |= SQLITE_OPEN_READONLY;
+    }else if( (db->flags & SQLITE_AttachCreate)==0 ){
+      flags &= ~SQLITE_OPEN_CREATE;
+    }
+    assert( pVfs );
+    flags |= SQLITE_OPEN_MAIN_DB;
+    rc = sqlite3BtreeOpen(pVfs, zPath, db, &pNew->pBt, 0, flags);
+    db->nDb++;
+    pNew->zDbSName = sqlite3DbStrDup(db, zName);
+  }
+  db->noSharedCache = 0;
+  if( rc==SQLITE_CONSTRAINT ){
+    rc = SQLITE_ERROR;
+    zErrDyn = sqlite3MPrintf(db, "database is already attached");
+  }else if( rc==SQLITE_OK ){
+    Pager *pPager;
+    pNew->pSchema = sqlite3SchemaGet(db, pNew->pBt);
+    if( !pNew->pSchema ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else if( pNew->pSchema->file_format && pNew->pSchema->enc!=ENC(db) ){
+      zErrDyn = sqlite3MPrintf(db,
+        "attached databases must use the same text encoding as main database");
+      rc = SQLITE_ERROR;
+    }
+    sqlite3BtreeEnter(pNew->pBt);
+    pPager = sqlite3BtreePager(pNew->pBt);
+    sqlite3PagerLockingMode(pPager, db->dfltLockMode);
+    sqlite3BtreeSecureDelete(pNew->pBt,
+                             sqlite3BtreeSecureDelete(db->aDb[0].pBt,-1) );
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+    sqlite3BtreeSetPagerFlags(pNew->pBt,
+                      PAGER_SYNCHRONOUS_FULL | (db->flags & PAGER_FLAGS_MASK));
+#endif
+    sqlite3BtreeLeave(pNew->pBt);
+  }
+  pNew->safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
+  if( rc==SQLITE_OK && pNew->zDbSName==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  sqlite3_free_filename( zPath );
+
+  /* If the file was opened successfully, read the schema for the new database.
+  ** If this fails, or if opening the file failed, then close the file and
+  ** remove the entry from the db->aDb[] array. i.e. put everything back the
+  ** way we found it.
+  */
+  if( rc==SQLITE_OK ){
+    sqlite3BtreeEnterAll(db);
+    db->init.iDb = 0;
+    db->mDbFlags &= ~(DBFLAG_SchemaKnownOk);
+    if( !REOPEN_AS_MEMDB(db) ){
+      rc = sqlite3Init(db, &zErrDyn);
+    }
+    sqlite3BtreeLeaveAll(db);
+    assert( zErrDyn==0 || rc!=SQLITE_OK );
+  }
+  if( rc ){
+    if( ALWAYS(!REOPEN_AS_MEMDB(db)) ){
+      int iDb = db->nDb - 1;
+      assert( iDb>=2 );
+      if( db->aDb[iDb].pBt ){
+        sqlite3BtreeClose(db->aDb[iDb].pBt);
+        db->aDb[iDb].pBt = 0;
+        db->aDb[iDb].pSchema = 0;
+      }
+      sqlite3ResetAllSchemasOfConnection(db);
+      db->nDb = iDb;
+      if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
+        sqlite3OomFault(db);
+        sqlite3DbFree(db, zErrDyn);
+        zErrDyn = sqlite3MPrintf(db, "out of memory");
+      }else if( zErrDyn==0 ){
+        zErrDyn = sqlite3MPrintf(db, "unable to open database: %s", zFile);
+      }
+    }
+    goto attach_error;
+  }
+
+  return;
+
+attach_error:
+  /* Return an error if we get here */
+  if( zErrDyn ){
+    sqlite3_result_error(context, zErrDyn, -1);
+    sqlite3DbFree(db, zErrDyn);
+  }
+  if( rc ) sqlite3_result_error_code(context, rc);
+}
+
+/*
+** An SQL user-function registered to do the work of an DETACH statement. The
+** three arguments to the function come directly from a detach statement:
+**
+**     DETACH DATABASE x
+**
+**     SELECT sqlite_detach(x)
+*/
+static void detachFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  const char *zName = (const char *)sqlite3_value_text(argv[0]);
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  int i;
+  Db *pDb = 0;
+  HashElem *pEntry;
+  char zErr[128];
+
+  UNUSED_PARAMETER(NotUsed);
+
+  if( zName==0 ) zName = "";
+  for(i=0; i<db->nDb; i++){
+    pDb = &db->aDb[i];
+    if( pDb->pBt==0 ) continue;
+    if( sqlite3DbIsNamed(db, i, zName) ) break;
+  }
+
+  if( i>=db->nDb ){
+    sqlite3_snprintf(sizeof(zErr),zErr, "no such database: %s", zName);
+    goto detach_error;
+  }
+  if( i<2 ){
+    sqlite3_snprintf(sizeof(zErr),zErr, "cannot detach database %s", zName);
+    goto detach_error;
+  }
+  if( sqlite3BtreeTxnState(pDb->pBt)!=SQLITE_TXN_NONE
+   || sqlite3BtreeIsInBackup(pDb->pBt)
+  ){
+    sqlite3_snprintf(sizeof(zErr),zErr, "database %s is locked", zName);
+    goto detach_error;
+  }
+
+  /* If any TEMP triggers reference the schema being detached, move those
+  ** triggers to reference the TEMP schema itself. */
+  assert( db->aDb[1].pSchema );
+  pEntry = sqliteHashFirst(&db->aDb[1].pSchema->trigHash);
+  while( pEntry ){
+    Trigger *pTrig = (Trigger*)sqliteHashData(pEntry);
+    if( pTrig->pTabSchema==pDb->pSchema ){
+      pTrig->pTabSchema = pTrig->pSchema;
+    }
+    pEntry = sqliteHashNext(pEntry);
+  }
+
+  sqlite3BtreeClose(pDb->pBt);
+  pDb->pBt = 0;
+  pDb->pSchema = 0;
+  sqlite3CollapseDatabaseArray(db);
+  return;
+
+detach_error:
+  sqlite3_result_error(context, zErr, -1);
+}
+
+/*
+** This procedure generates VDBE code for a single invocation of either the
+** sqlite_detach() or sqlite_attach() SQL user functions.
+*/
+static void codeAttach(
+  Parse *pParse,       /* The parser context */
+  int type,            /* Either SQLITE_ATTACH or SQLITE_DETACH */
+  FuncDef const *pFunc,/* FuncDef wrapper for detachFunc() or attachFunc() */
+  Expr *pAuthArg,      /* Expression to pass to authorization callback */
+  Expr *pFilename,     /* Name of database file */
+  Expr *pDbname,       /* Name of the database to use internally */
+  Expr *pKey           /* Database key for encryption extension */
+){
+  int rc;
+  NameContext sName;
+  Vdbe *v;
+  sqlite3* db = pParse->db;
+  int regArgs;
+
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ) goto attach_end;
+
+  if( pParse->nErr ) goto attach_end;
+  memset(&sName, 0, sizeof(NameContext));
+  sName.pParse = pParse;
+
+  if(
+      SQLITE_OK!=resolveAttachExpr(&sName, pFilename) ||
+      SQLITE_OK!=resolveAttachExpr(&sName, pDbname) ||
+      SQLITE_OK!=resolveAttachExpr(&sName, pKey)
+  ){
+    goto attach_end;
+  }
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( ALWAYS(pAuthArg) ){
+    char *zAuthArg;
+    if( pAuthArg->op==TK_STRING ){
+      assert( !ExprHasProperty(pAuthArg, EP_IntValue) );
+      zAuthArg = pAuthArg->u.zToken;
+    }else{
+      zAuthArg = 0;
+    }
+    rc = sqlite3AuthCheck(pParse, type, zAuthArg, 0, 0);
+    if(rc!=SQLITE_OK ){
+      goto attach_end;
+    }
+  }
+#endif /* SQLITE_OMIT_AUTHORIZATION */
+
+
+  v = sqlite3GetVdbe(pParse);
+  regArgs = sqlite3GetTempRange(pParse, 4);
+  sqlite3ExprCode(pParse, pFilename, regArgs);
+  sqlite3ExprCode(pParse, pDbname, regArgs+1);
+  sqlite3ExprCode(pParse, pKey, regArgs+2);
+
+  assert( v || db->mallocFailed );
+  if( v ){
+    sqlite3VdbeAddFunctionCall(pParse, 0, regArgs+3-pFunc->nArg, regArgs+3,
+                               pFunc->nArg, pFunc, 0);
+    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
+    ** statement only). For DETACH, set it to false (expire all existing
+    ** statements).
+    */
+    sqlite3VdbeAddOp1(v, OP_Expire, (type==SQLITE_ATTACH));
+  }
+
+attach_end:
+  sqlite3ExprDelete(db, pFilename);
+  sqlite3ExprDelete(db, pDbname);
+  sqlite3ExprDelete(db, pKey);
+}
+
+/*
+** Called by the parser to compile a DETACH statement.
+**
+**     DETACH pDbname
+*/
+SQLITE_PRIVATE void sqlite3Detach(Parse *pParse, Expr *pDbname){
+  static const FuncDef detach_func = {
+    1,                /* nArg */
+    SQLITE_UTF8,      /* funcFlags */
+    0,                /* pUserData */
+    0,                /* pNext */
+    detachFunc,       /* xSFunc */
+    0,                /* xFinalize */
+    0, 0,             /* xValue, xInverse */
+    "sqlite_detach",  /* zName */
+    {0}
+  };
+  codeAttach(pParse, SQLITE_DETACH, &detach_func, pDbname, 0, 0, pDbname);
+}
+
+/*
+** Called by the parser to compile an ATTACH statement.
+**
+**     ATTACH p AS pDbname KEY pKey
+*/
+SQLITE_PRIVATE void sqlite3Attach(Parse *pParse, Expr *p, Expr *pDbname, Expr *pKey){
+  static const FuncDef attach_func = {
+    3,                /* nArg */
+    SQLITE_UTF8,      /* funcFlags */
+    0,                /* pUserData */
+    0,                /* pNext */
+    attachFunc,       /* xSFunc */
+    0,                /* xFinalize */
+    0, 0,             /* xValue, xInverse */
+    "sqlite_attach",  /* zName */
+    {0}
+  };
+  codeAttach(pParse, SQLITE_ATTACH, &attach_func, p, p, pDbname, pKey);
+}
+#endif /* SQLITE_OMIT_ATTACH */
+
+/*
+** Expression callback used by sqlite3FixAAAA() routines.
+*/
+static int fixExprCb(Walker *p, Expr *pExpr){
+  DbFixer *pFix = p->u.pFix;
+  if( !pFix->bTemp ) ExprSetProperty(pExpr, EP_FromDDL);
+  if( pExpr->op==TK_VARIABLE ){
+    if( pFix->pParse->db->init.busy ){
+      pExpr->op = TK_NULL;
+    }else{
+      sqlite3ErrorMsg(pFix->pParse, "%s cannot use variables", pFix->zType);
+      return WRC_Abort;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Select callback used by sqlite3FixAAAA() routines.
+*/
+static int fixSelectCb(Walker *p, Select *pSelect){
+  DbFixer *pFix = p->u.pFix;
+  int i;
+  SrcItem *pItem;
+  sqlite3 *db = pFix->pParse->db;
+  int iDb = sqlite3FindDbName(db, pFix->zDb);
+  SrcList *pList = pSelect->pSrc;
+
+  if( NEVER(pList==0) ) return WRC_Continue;
+  for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
+    if( pFix->bTemp==0 && pItem->fg.isSubquery==0 ){
+      if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+        if( iDb!=sqlite3FindDbName(db, pItem->u4.zDatabase) ){
+          sqlite3ErrorMsg(pFix->pParse,
+              "%s %T cannot reference objects in database %s",
+              pFix->zType, pFix->pName, pItem->u4.zDatabase);
+          return WRC_Abort;
+        }
+        sqlite3DbFree(db, pItem->u4.zDatabase);
+        pItem->fg.notCte = 1;
+        pItem->fg.hadSchema = 1;
+      }
+      pItem->u4.pSchema = pFix->pSchema;
+      pItem->fg.fromDDL = 1;
+      pItem->fg.fixedSchema = 1;
+    }
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
+    if( pList->a[i].fg.isUsing==0
+     && sqlite3WalkExpr(&pFix->w, pList->a[i].u3.pOn)
+    ){
+      return WRC_Abort;
+    }
+#endif
+  }
+  if( pSelect->pWith ){
+    for(i=0; i<pSelect->pWith->nCte; i++){
+      if( sqlite3WalkSelect(p, pSelect->pWith->a[i].pSelect) ){
+        return WRC_Abort;
+      }
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Initialize a DbFixer structure.  This routine must be called prior
+** to passing the structure to one of the sqliteFixAAAA() routines below.
+*/
+SQLITE_PRIVATE void sqlite3FixInit(
+  DbFixer *pFix,      /* The fixer to be initialized */
+  Parse *pParse,      /* Error messages will be written here */
+  int iDb,            /* This is the database that must be used */
+  const char *zType,  /* "view", "trigger", or "index" */
+  const Token *pName  /* Name of the view, trigger, or index */
+){
+  sqlite3 *db = pParse->db;
+  assert( db->nDb>iDb );
+  pFix->pParse = pParse;
+  pFix->zDb = db->aDb[iDb].zDbSName;
+  pFix->pSchema = db->aDb[iDb].pSchema;
+  pFix->zType = zType;
+  pFix->pName = pName;
+  pFix->bTemp = (iDb==1);
+  pFix->w.pParse = pParse;
+  pFix->w.xExprCallback = fixExprCb;
+  pFix->w.xSelectCallback = fixSelectCb;
+  pFix->w.xSelectCallback2 = sqlite3WalkWinDefnDummyCallback;
+  pFix->w.walkerDepth = 0;
+  pFix->w.eCode = 0;
+  pFix->w.u.pFix = pFix;
+}
+
+/*
+** The following set of routines walk through the parse tree and assign
+** a specific database to all table references where the database name
+** was left unspecified in the original SQL statement.  The pFix structure
+** must have been initialized by a prior call to sqlite3FixInit().
+**
+** These routines are used to make sure that an index, trigger, or
+** view in one database does not refer to objects in a different database.
+** (Exception: indices, triggers, and views in the TEMP database are
+** allowed to refer to anything.)  If a reference is explicitly made
+** to an object in a different database, an error message is added to
+** pParse->zErrMsg and these routines return non-zero.  If everything
+** checks out, these routines return 0.
+*/
+SQLITE_PRIVATE int sqlite3FixSrcList(
+  DbFixer *pFix,       /* Context of the fixation */
+  SrcList *pList       /* The Source list to check and modify */
+){
+  int res = 0;
+  if( pList ){
+    Select s;
+    memset(&s, 0, sizeof(s));
+    s.pSrc = pList;
+    res = sqlite3WalkSelect(&pFix->w, &s);
+  }
+  return res;
+}
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
+SQLITE_PRIVATE int sqlite3FixSelect(
+  DbFixer *pFix,       /* Context of the fixation */
+  Select *pSelect      /* The SELECT statement to be fixed to one database */
+){
+  return sqlite3WalkSelect(&pFix->w, pSelect);
+}
+SQLITE_PRIVATE int sqlite3FixExpr(
+  DbFixer *pFix,     /* Context of the fixation */
+  Expr *pExpr        /* The expression to be fixed to one database */
+){
+  return sqlite3WalkExpr(&pFix->w, pExpr);
+}
+#endif
+
+#ifndef SQLITE_OMIT_TRIGGER
+SQLITE_PRIVATE int sqlite3FixTriggerStep(
+  DbFixer *pFix,     /* Context of the fixation */
+  TriggerStep *pStep /* The trigger step be fixed to one database */
+){
+  while( pStep ){
+    if( sqlite3WalkSelect(&pFix->w, pStep->pSelect)
+     || sqlite3WalkExpr(&pFix->w, pStep->pWhere)
+     || sqlite3WalkExprList(&pFix->w, pStep->pExprList)
+     || sqlite3FixSrcList(pFix, pStep->pFrom)
+    ){
+      return 1;
+    }
+#ifndef SQLITE_OMIT_UPSERT
+    {
+      Upsert *pUp;
+      for(pUp=pStep->pUpsert; pUp; pUp=pUp->pNextUpsert){
+        if( sqlite3WalkExprList(&pFix->w, pUp->pUpsertTarget)
+         || sqlite3WalkExpr(&pFix->w, pUp->pUpsertTargetWhere)
+         || sqlite3WalkExprList(&pFix->w, pUp->pUpsertSet)
+         || sqlite3WalkExpr(&pFix->w, pUp->pUpsertWhere)
+        ){
+          return 1;
+        }
+      }
+    }
+#endif
+    pStep = pStep->pNext;
+  }
+
+  return 0;
+}
+#endif
+
+/************** End of attach.c **********************************************/
+/************** Begin file auth.c ********************************************/
+/*
+** 2003 January 11
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the sqlite3_set_authorizer()
+** API.  This facility is an optional feature of the library.  Embedded
+** systems that do not need this facility may omit it by recompiling
+** the library with -DSQLITE_OMIT_AUTHORIZATION=1
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** All of the code in this file may be omitted by defining a single
+** macro.
+*/
+#ifndef SQLITE_OMIT_AUTHORIZATION
+
+/*
+** Set or clear the access authorization function.
+**
+** The access authorization function is be called during the compilation
+** phase to verify that the user has read and/or write access permission on
+** various fields of the database.  The first argument to the auth function
+** is a copy of the 3rd argument to this routine.  The second argument
+** to the auth function is one of these constants:
+**
+**       SQLITE_CREATE_INDEX
+**       SQLITE_CREATE_TABLE
+**       SQLITE_CREATE_TEMP_INDEX
+**       SQLITE_CREATE_TEMP_TABLE
+**       SQLITE_CREATE_TEMP_TRIGGER
+**       SQLITE_CREATE_TEMP_VIEW
+**       SQLITE_CREATE_TRIGGER
+**       SQLITE_CREATE_VIEW
+**       SQLITE_DELETE
+**       SQLITE_DROP_INDEX
+**       SQLITE_DROP_TABLE
+**       SQLITE_DROP_TEMP_INDEX
+**       SQLITE_DROP_TEMP_TABLE
+**       SQLITE_DROP_TEMP_TRIGGER
+**       SQLITE_DROP_TEMP_VIEW
+**       SQLITE_DROP_TRIGGER
+**       SQLITE_DROP_VIEW
+**       SQLITE_INSERT
+**       SQLITE_PRAGMA
+**       SQLITE_READ
+**       SQLITE_SELECT
+**       SQLITE_TRANSACTION
+**       SQLITE_UPDATE
+**
+** The third and fourth arguments to the auth function are the name of
+** the table and the column that are being accessed.  The auth function
+** should return either SQLITE_OK, SQLITE_DENY, or SQLITE_IGNORE.  If
+** SQLITE_OK is returned, it means that access is allowed.  SQLITE_DENY
+** means that the SQL statement will never-run - the sqlite3_exec() call
+** will return with an error.  SQLITE_IGNORE means that the SQL statement
+** should run but attempts to read the specified column will return NULL
+** and attempts to write the column will be ignored.
+**
+** Setting the auth function to NULL disables this hook.  The default
+** setting of the auth function is NULL.
+*/
+SQLITE_API int sqlite3_set_authorizer(
+  sqlite3 *db,
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
+  void *pArg
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->xAuth = (sqlite3_xauth)xAuth;
+  db->pAuthArg = pArg;
+  if( db->xAuth ) sqlite3ExpirePreparedStatements(db, 1);
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Write an error message into pParse->zErrMsg that explains that the
+** user-supplied authorization function returned an illegal value.
+*/
+static void sqliteAuthBadReturnCode(Parse *pParse){
+  sqlite3ErrorMsg(pParse, "authorizer malfunction");
+  pParse->rc = SQLITE_ERROR;
+}
+
+/*
+** Invoke the authorization callback for permission to read column zCol from
+** table zTab in database zDb. This function assumes that an authorization
+** callback has been registered (i.e. that sqlite3.xAuth is not NULL).
+**
+** If SQLITE_IGNORE is returned and pExpr is not NULL, then pExpr is changed
+** to an SQL NULL expression. Otherwise, if pExpr is NULL, then SQLITE_IGNORE
+** is treated as SQLITE_DENY. In this case an error is left in pParse.
+*/
+SQLITE_PRIVATE int sqlite3AuthReadCol(
+  Parse *pParse,                  /* The parser context */
+  const char *zTab,               /* Table name */
+  const char *zCol,               /* Column name */
+  int iDb                         /* Index of containing database. */
+){
+  sqlite3 *db = pParse->db;          /* Database handle */
+  char *zDb = db->aDb[iDb].zDbSName; /* Schema name of attached database */
+  int rc;                            /* Auth callback return code */
+
+  if( db->init.busy ) return SQLITE_OK;
+  rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext);
+  if( rc==SQLITE_DENY ){
+    char *z = sqlite3_mprintf("%s.%s", zTab, zCol);
+    if( db->nDb>2 || iDb!=0 ) z = sqlite3_mprintf("%s.%z", zDb, z);
+    sqlite3ErrorMsg(pParse, "access to %z is prohibited", z);
+    pParse->rc = SQLITE_AUTH;
+  }else if( rc!=SQLITE_IGNORE && rc!=SQLITE_OK ){
+    sqliteAuthBadReturnCode(pParse);
+  }
+  return rc;
+}
+
+/*
+** The pExpr should be a TK_COLUMN expression.  The table referred to
+** is in pTabList or else it is the NEW or OLD table of a trigger.
+** Check to see if it is OK to read this particular column.
+**
+** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN
+** instruction into a TK_NULL.  If the auth function returns SQLITE_DENY,
+** then generate an error.
+*/
+SQLITE_PRIVATE void sqlite3AuthRead(
+  Parse *pParse,        /* The parser context */
+  Expr *pExpr,          /* The expression to check authorization on */
+  Schema *pSchema,      /* The schema of the expression */
+  SrcList *pTabList     /* All table that pExpr might refer to */
+){
+  Table *pTab = 0;      /* The table being read */
+  const char *zCol;     /* Name of the column of the table */
+  int iSrc;             /* Index in pTabList->a[] of table being read */
+  int iDb;              /* The index of the database the expression refers to */
+  int iCol;             /* Index of column in table */
+
+  assert( pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER );
+  assert( !IN_RENAME_OBJECT );
+  assert( pParse->db->xAuth!=0 );
+  iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
+  if( iDb<0 ){
+    /* An attempt to read a column out of a subquery or other
+    ** temporary table. */
+    return;
+  }
+
+  if( pExpr->op==TK_TRIGGER ){
+    pTab = pParse->pTriggerTab;
+  }else{
+    assert( pTabList );
+    for(iSrc=0; iSrc<pTabList->nSrc; iSrc++){
+      if( pExpr->iTable==pTabList->a[iSrc].iCursor ){
+        pTab = pTabList->a[iSrc].pSTab;
+        break;
+      }
+    }
+  }
+  iCol = pExpr->iColumn;
+  if( pTab==0 ) return;
+
+  if( iCol>=0 ){
+    assert( iCol<pTab->nCol );
+    zCol = pTab->aCol[iCol].zCnName;
+  }else if( pTab->iPKey>=0 ){
+    assert( pTab->iPKey<pTab->nCol );
+    zCol = pTab->aCol[pTab->iPKey].zCnName;
+  }else{
+    zCol = "ROWID";
+  }
+  assert( iDb>=0 && iDb<pParse->db->nDb );
+  if( SQLITE_IGNORE==sqlite3AuthReadCol(pParse, pTab->zName, zCol, iDb) ){
+    pExpr->op = TK_NULL;
+  }
+}
+
+/*
+** Do an authorization check using the code and arguments given.  Return
+** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY.  If SQLITE_DENY
+** is returned, then the error count and error message in pParse are
+** modified appropriately.
+*/
+SQLITE_PRIVATE int sqlite3AuthCheck(
+  Parse *pParse,
+  int code,
+  const char *zArg1,
+  const char *zArg2,
+  const char *zArg3
+){
+  sqlite3 *db = pParse->db;
+  int rc;
+
+  /* Don't do any authorization checks if the database is initializing
+  ** or if the parser is being invoked from within sqlite3_declare_vtab.
+  */
+  assert( !IN_RENAME_OBJECT || db->xAuth==0 );
+  if( db->xAuth==0 || db->init.busy || IN_SPECIAL_PARSE ){
+    return SQLITE_OK;
+  }
+
+  /* EVIDENCE-OF: R-43249-19882 The third through sixth parameters to the
+  ** callback are either NULL pointers or zero-terminated strings that
+  ** contain additional details about the action to be authorized.
+  **
+  ** The following testcase() macros show that any of the 3rd through 6th
+  ** parameters can be either NULL or a string. */
+  testcase( zArg1==0 );
+  testcase( zArg2==0 );
+  testcase( zArg3==0 );
+  testcase( pParse->zAuthContext==0 );
+
+  rc = db->xAuth(db->pAuthArg,code,zArg1,zArg2,zArg3,pParse->zAuthContext);
+  if( rc==SQLITE_DENY ){
+    sqlite3ErrorMsg(pParse, "not authorized");
+    pParse->rc = SQLITE_AUTH;
+  }else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
+    rc = SQLITE_DENY;
+    sqliteAuthBadReturnCode(pParse);
+  }
+  return rc;
+}
+
+/*
+** Push an authorization context.  After this routine is called, the
+** zArg3 argument to authorization callbacks will be zContext until
+** popped.  Or if pParse==0, this routine is a no-op.
+*/
+SQLITE_PRIVATE void sqlite3AuthContextPush(
+  Parse *pParse,
+  AuthContext *pContext,
+  const char *zContext
+){
+  assert( pParse );
+  pContext->pParse = pParse;
+  pContext->zAuthContext = pParse->zAuthContext;
+  pParse->zAuthContext = zContext;
+}
+
+/*
+** Pop an authorization context that was previously pushed
+** by sqlite3AuthContextPush
+*/
+SQLITE_PRIVATE void sqlite3AuthContextPop(AuthContext *pContext){
+  if( pContext->pParse ){
+    pContext->pParse->zAuthContext = pContext->zAuthContext;
+    pContext->pParse = 0;
+  }
+}
+
+#endif /* SQLITE_OMIT_AUTHORIZATION */
+
+/************** End of auth.c ************************************************/
+/************** Begin file build.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the SQLite parser
+** when syntax rules are reduced.  The routines in this file handle the
+** following kinds of SQL syntax:
+**
+**     CREATE TABLE
+**     DROP TABLE
+**     CREATE INDEX
+**     DROP INDEX
+**     creating ID lists
+**     BEGIN TRANSACTION
+**     COMMIT
+**     ROLLBACK
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+/*
+** The TableLock structure is only used by the sqlite3TableLock() and
+** codeTableLocks() functions.
+*/
+struct TableLock {
+  int iDb;               /* The database containing the table to be locked */
+  Pgno iTab;             /* The root page of the table to be locked */
+  u8 isWriteLock;        /* True for write lock.  False for a read lock */
+  const char *zLockName; /* Name of the table */
+};
+
+/*
+** Record the fact that we want to lock a table at run-time.
+**
+** The table to be locked has root page iTab and is found in database iDb.
+** A read or a write lock can be taken depending on isWritelock.
+**
+** This routine just records the fact that the lock is desired.  The
+** code to make the lock occur is generated by a later call to
+** codeTableLocks() which occurs during sqlite3FinishCoding().
+*/
+static SQLITE_NOINLINE void lockTable(
+  Parse *pParse,     /* Parsing context */
+  int iDb,           /* Index of the database containing the table to lock */
+  Pgno iTab,         /* Root page number of the table to be locked */
+  u8 isWriteLock,    /* True for a write lock */
+  const char *zName  /* Name of the table to be locked */
+){
+  Parse *pToplevel;
+  int i;
+  int nBytes;
+  TableLock *p;
+  assert( iDb>=0 );
+
+  pToplevel = sqlite3ParseToplevel(pParse);
+  for(i=0; i<pToplevel->nTableLock; i++){
+    p = &pToplevel->aTableLock[i];
+    if( p->iDb==iDb && p->iTab==iTab ){
+      p->isWriteLock = (p->isWriteLock || isWriteLock);
+      return;
+    }
+  }
+
+  nBytes = sizeof(TableLock) * (pToplevel->nTableLock+1);
+  pToplevel->aTableLock =
+      sqlite3DbReallocOrFree(pToplevel->db, pToplevel->aTableLock, nBytes);
+  if( pToplevel->aTableLock ){
+    p = &pToplevel->aTableLock[pToplevel->nTableLock++];
+    p->iDb = iDb;
+    p->iTab = iTab;
+    p->isWriteLock = isWriteLock;
+    p->zLockName = zName;
+  }else{
+    pToplevel->nTableLock = 0;
+    sqlite3OomFault(pToplevel->db);
+  }
+}
+SQLITE_PRIVATE void sqlite3TableLock(
+  Parse *pParse,     /* Parsing context */
+  int iDb,           /* Index of the database containing the table to lock */
+  Pgno iTab,         /* Root page number of the table to be locked */
+  u8 isWriteLock,    /* True for a write lock */
+  const char *zName  /* Name of the table to be locked */
+){
+  if( iDb==1 ) return;
+  if( !sqlite3BtreeSharable(pParse->db->aDb[iDb].pBt) ) return;
+  lockTable(pParse, iDb, iTab, isWriteLock, zName);
+}
+
+/*
+** Code an OP_TableLock instruction for each table locked by the
+** statement (configured by calls to sqlite3TableLock()).
+*/
+static void codeTableLocks(Parse *pParse){
+  int i;
+  Vdbe *pVdbe = pParse->pVdbe;
+  assert( pVdbe!=0 );
+
+  for(i=0; i<pParse->nTableLock; i++){
+    TableLock *p = &pParse->aTableLock[i];
+    int p1 = p->iDb;
+    sqlite3VdbeAddOp4(pVdbe, OP_TableLock, p1, p->iTab, p->isWriteLock,
+                      p->zLockName, P4_STATIC);
+  }
+}
+#else
+  #define codeTableLocks(x)
+#endif
+
+/*
+** Return TRUE if the given yDbMask object is empty - if it contains no
+** 1 bits.  This routine is used by the DbMaskAllZero() and DbMaskNotZero()
+** macros when SQLITE_MAX_ATTACHED is greater than 30.
+*/
+#if SQLITE_MAX_ATTACHED>30
+SQLITE_PRIVATE int sqlite3DbMaskAllZero(yDbMask m){
+  int i;
+  for(i=0; i<sizeof(yDbMask); i++) if( m[i] ) return 0;
+  return 1;
+}
+#endif
+
+/*
+** This routine is called after a single SQL statement has been
+** parsed and a VDBE program to execute that statement has been
+** prepared.  This routine puts the finishing touches on the
+** VDBE program and resets the pParse structure for the next
+** parse.
+**
+** Note that if an error occurred, it might be the case that
+** no VDBE code was generated.
+*/
+SQLITE_PRIVATE void sqlite3FinishCoding(Parse *pParse){
+  sqlite3 *db;
+  Vdbe *v;
+  int iDb, i;
+
+  assert( pParse->pToplevel==0 );
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nested ) return;
+  if( pParse->nErr ){
+    if( db->mallocFailed ) pParse->rc = SQLITE_NOMEM;
+    return;
+  }
+  assert( db->mallocFailed==0 );
+
+  /* Begin by generating some termination code at the end of the
+  ** vdbe program
+  */
+  v = pParse->pVdbe;
+  if( v==0 ){
+    if( db->init.busy ){
+      pParse->rc = SQLITE_DONE;
+      return;
+    }
+    v = sqlite3GetVdbe(pParse);
+    if( v==0 ) pParse->rc = SQLITE_ERROR;
+  }
+  assert( !pParse->isMultiWrite
+       || sqlite3VdbeAssertMayAbort(v, pParse->mayAbort));
+  if( v ){
+    if( pParse->bReturning ){
+      Returning *pReturning = pParse->u1.pReturning;
+      int addrRewind;
+      int reg;
+
+      if( pReturning->nRetCol ){
+        sqlite3VdbeAddOp0(v, OP_FkCheck);
+        addrRewind =
+           sqlite3VdbeAddOp1(v, OP_Rewind, pReturning->iRetCur);
+        VdbeCoverage(v);
+        reg = pReturning->iRetReg;
+        for(i=0; i<pReturning->nRetCol; i++){
+          sqlite3VdbeAddOp3(v, OP_Column, pReturning->iRetCur, i, reg+i);
+        }
+        sqlite3VdbeAddOp2(v, OP_ResultRow, reg, i);
+        sqlite3VdbeAddOp2(v, OP_Next, pReturning->iRetCur, addrRewind+1);
+        VdbeCoverage(v);
+        sqlite3VdbeJumpHere(v, addrRewind);
+      }
+    }
+    sqlite3VdbeAddOp0(v, OP_Halt);
+
+    /* The cookie mask contains one bit for each database file open.
+    ** (Bit 0 is for main, bit 1 is for temp, and so forth.)  Bits are
+    ** set for each database that is used.  Generate code to start a
+    ** transaction on each used database and to verify the schema cookie
+    ** on each used database.
+    */
+    assert( pParse->nErr>0 || sqlite3VdbeGetOp(v, 0)->opcode==OP_Init );
+    sqlite3VdbeJumpHere(v, 0);
+    assert( db->nDb>0 );
+    iDb = 0;
+    do{
+      Schema *pSchema;
+      if( DbMaskTest(pParse->cookieMask, iDb)==0 ) continue;
+      sqlite3VdbeUsesBtree(v, iDb);
+      pSchema = db->aDb[iDb].pSchema;
+      sqlite3VdbeAddOp4Int(v,
+        OP_Transaction,                    /* Opcode */
+        iDb,                               /* P1 */
+        DbMaskTest(pParse->writeMask,iDb), /* P2 */
+        pSchema->schema_cookie,            /* P3 */
+        pSchema->iGeneration               /* P4 */
+      );
+      if( db->init.busy==0 ) sqlite3VdbeChangeP5(v, 1);
+      VdbeComment((v,
+            "usesStmtJournal=%d", pParse->mayAbort && pParse->isMultiWrite));
+    }while( ++iDb<db->nDb );
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    for(i=0; i<pParse->nVtabLock; i++){
+      char *vtab = (char *)sqlite3GetVTable(db, pParse->apVtabLock[i]);
+      sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
+    }
+    pParse->nVtabLock = 0;
+#endif
+
+#ifndef SQLITE_OMIT_SHARED_CACHE
+    /* Once all the cookies have been verified and transactions opened,
+    ** obtain the required table-locks. This is a no-op unless the
+    ** shared-cache feature is enabled.
+    */
+    if( pParse->nTableLock ) codeTableLocks(pParse);
+#endif
+
+    /* Initialize any AUTOINCREMENT data structures required.
+    */
+    if( pParse->pAinc ) sqlite3AutoincrementBegin(pParse);
+
+    /* Code constant expressions that were factored out of inner loops.
+    */
+    if( pParse->pConstExpr ){
+      ExprList *pEL = pParse->pConstExpr;
+      pParse->okConstFactor = 0;
+      for(i=0; i<pEL->nExpr; i++){
+        assert( pEL->a[i].u.iConstExprReg>0 );
+        sqlite3ExprCode(pParse, pEL->a[i].pExpr, pEL->a[i].u.iConstExprReg);
+      }
+    }
+
+    if( pParse->bReturning ){
+      Returning *pRet = pParse->u1.pReturning;
+      if( pRet->nRetCol ){
+        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRet->iRetCur, pRet->nRetCol);
+      }
+    }
+
+    /* Finally, jump back to the beginning of the executable code. */
+    sqlite3VdbeGoto(v, 1);
+  }
+
+  /* Get the VDBE program ready for execution
+  */
+  assert( v!=0 || pParse->nErr );
+  assert( db->mallocFailed==0 || pParse->nErr );
+  if( pParse->nErr==0 ){
+    /* A minimum of one cursor is required if autoincrement is used
+    *  See ticket [a696379c1f08866] */
+    assert( pParse->pAinc==0 || pParse->nTab>0 );
+    sqlite3VdbeMakeReady(v, pParse);
+    pParse->rc = SQLITE_DONE;
+  }else{
+    pParse->rc = SQLITE_ERROR;
+  }
+}
+
+/*
+** Run the parser and code generator recursively in order to generate
+** code for the SQL statement given onto the end of the pParse context
+** currently under construction.  Notes:
+**
+**   *  The final OP_Halt is not appended and other initialization
+**      and finalization steps are omitted because those are handling by the
+**      outermost parser.
+**
+**   *  Built-in SQL functions always take precedence over application-defined
+**      SQL functions.  In other words, it is not possible to override a
+**      built-in function.
+*/
+SQLITE_PRIVATE void sqlite3NestedParse(Parse *pParse, const char *zFormat, ...){
+  va_list ap;
+  char *zSql;
+  sqlite3 *db = pParse->db;
+  u32 savedDbFlags = db->mDbFlags;
+  char saveBuf[PARSE_TAIL_SZ];
+
+  if( pParse->nErr ) return;
+  if( pParse->eParseMode ) return;
+  assert( pParse->nested<10 );  /* Nesting should only be of limited depth */
+  va_start(ap, zFormat);
+  zSql = sqlite3VMPrintf(db, zFormat, ap);
+  va_end(ap);
+  if( zSql==0 ){
+    /* This can result either from an OOM or because the formatted string
+    ** exceeds SQLITE_LIMIT_LENGTH.  In the latter case, we need to set
+    ** an error */
+    if( !db->mallocFailed ) pParse->rc = SQLITE_TOOBIG;
+    pParse->nErr++;
+    return;
+  }
+  pParse->nested++;
+  memcpy(saveBuf, PARSE_TAIL(pParse), PARSE_TAIL_SZ);
+  memset(PARSE_TAIL(pParse), 0, PARSE_TAIL_SZ);
+  db->mDbFlags |= DBFLAG_PreferBuiltin;
+  sqlite3RunParser(pParse, zSql);
+  db->mDbFlags = savedDbFlags;
+  sqlite3DbFree(db, zSql);
+  memcpy(PARSE_TAIL(pParse), saveBuf, PARSE_TAIL_SZ);
+  pParse->nested--;
+}
+
+/*
+** Locate the in-memory structure that describes a particular database
+** table given the name of that table and (optionally) the name of the
+** database containing the table.  Return NULL if not found.
+**
+** If zDatabase is 0, all databases are searched for the table and the
+** first matching table is returned.  (No checking for duplicate table
+** names is done.)  The search order is TEMP first, then MAIN, then any
+** auxiliary databases added using the ATTACH command.
+**
+** See also sqlite3LocateTable().
+*/
+SQLITE_PRIVATE Table *sqlite3FindTable(sqlite3 *db, const char *zName, const char *zDatabase){
+  Table *p = 0;
+  int i;
+
+  /* All mutexes are required for schema access.  Make sure we hold them. */
+  assert( zDatabase!=0 || sqlite3BtreeHoldsAllMutexes(db) );
+  if( zDatabase ){
+    for(i=0; i<db->nDb; i++){
+      if( sqlite3StrICmp(zDatabase, db->aDb[i].zDbSName)==0 ) break;
+    }
+    if( i>=db->nDb ){
+      /* No match against the official names.  But always match "main"
+      ** to schema 0 as a legacy fallback. */
+      if( sqlite3StrICmp(zDatabase,"main")==0 ){
+        i = 0;
+      }else{
+        return 0;
+      }
+    }
+    p = sqlite3HashFind(&db->aDb[i].pSchema->tblHash, zName);
+    if( p==0 && sqlite3StrNICmp(zName, "sqlite_", 7)==0 ){
+      if( i==1 ){
+        if( sqlite3StrICmp(zName+7, &PREFERRED_TEMP_SCHEMA_TABLE[7])==0
+         || sqlite3StrICmp(zName+7, &PREFERRED_SCHEMA_TABLE[7])==0
+         || sqlite3StrICmp(zName+7, &LEGACY_SCHEMA_TABLE[7])==0
+        ){
+          p = sqlite3HashFind(&db->aDb[1].pSchema->tblHash,
+                              LEGACY_TEMP_SCHEMA_TABLE);
+        }
+      }else{
+        if( sqlite3StrICmp(zName+7, &PREFERRED_SCHEMA_TABLE[7])==0 ){
+          p = sqlite3HashFind(&db->aDb[i].pSchema->tblHash,
+                              LEGACY_SCHEMA_TABLE);
+        }
+      }
+    }
+  }else{
+    /* Match against TEMP first */
+    p = sqlite3HashFind(&db->aDb[1].pSchema->tblHash, zName);
+    if( p ) return p;
+    /* The main database is second */
+    p = sqlite3HashFind(&db->aDb[0].pSchema->tblHash, zName);
+    if( p ) return p;
+    /* Attached databases are in order of attachment */
+    for(i=2; i<db->nDb; i++){
+      assert( sqlite3SchemaMutexHeld(db, i, 0) );
+      p = sqlite3HashFind(&db->aDb[i].pSchema->tblHash, zName);
+      if( p ) break;
+    }
+    if( p==0 && sqlite3StrNICmp(zName, "sqlite_", 7)==0 ){
+      if( sqlite3StrICmp(zName+7, &PREFERRED_SCHEMA_TABLE[7])==0 ){
+        p = sqlite3HashFind(&db->aDb[0].pSchema->tblHash, LEGACY_SCHEMA_TABLE);
+      }else if( sqlite3StrICmp(zName+7, &PREFERRED_TEMP_SCHEMA_TABLE[7])==0 ){
+        p = sqlite3HashFind(&db->aDb[1].pSchema->tblHash,
+                            LEGACY_TEMP_SCHEMA_TABLE);
+      }
+    }
+  }
+  return p;
+}
+
+/*
+** Locate the in-memory structure that describes a particular database
+** table given the name of that table and (optionally) the name of the
+** database containing the table.  Return NULL if not found.  Also leave an
+** error message in pParse->zErrMsg.
+**
+** The difference between this routine and sqlite3FindTable() is that this
+** routine leaves an error message in pParse->zErrMsg where
+** sqlite3FindTable() does not.
+*/
+SQLITE_PRIVATE Table *sqlite3LocateTable(
+  Parse *pParse,         /* context in which to report errors */
+  u32 flags,             /* LOCATE_VIEW or LOCATE_NOERR */
+  const char *zName,     /* Name of the table we are looking for */
+  const char *zDbase     /* Name of the database.  Might be NULL */
+){
+  Table *p;
+  sqlite3 *db = pParse->db;
+
+  /* Read the database schema. If an error occurs, leave an error message
+  ** and code in pParse and return NULL. */
+  if( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0
+   && SQLITE_OK!=sqlite3ReadSchema(pParse)
+  ){
+    return 0;
+  }
+
+  p = sqlite3FindTable(db, zName, zDbase);
+  if( p==0 ){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    /* If zName is the not the name of a table in the schema created using
+    ** CREATE, then check to see if it is the name of an virtual table that
+    ** can be an eponymous virtual table. */
+    if( (pParse->prepFlags & SQLITE_PREPARE_NO_VTAB)==0 && db->init.busy==0 ){
+      Module *pMod = (Module*)sqlite3HashFind(&db->aModule, zName);
+      if( pMod==0 && sqlite3_strnicmp(zName, "pragma_", 7)==0 ){
+        pMod = sqlite3PragmaVtabRegister(db, zName);
+      }
+      if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
+        testcase( pMod->pEpoTab==0 );
+        return pMod->pEpoTab;
+      }
+    }
+#endif
+    if( flags & LOCATE_NOERR ) return 0;
+    pParse->checkSchema = 1;
+  }else if( IsVirtual(p) && (pParse->prepFlags & SQLITE_PREPARE_NO_VTAB)!=0 ){
+    p = 0;
+  }
+
+  if( p==0 ){
+    const char *zMsg = flags & LOCATE_VIEW ? "no such view" : "no such table";
+    if( zDbase ){
+      sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
+    }else{
+      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
+    }
+  }else{
+    assert( HasRowid(p) || p->iPKey<0 );
+  }
+
+  return p;
+}
+
+/*
+** Locate the table identified by *p.
+**
+** This is a wrapper around sqlite3LocateTable(). The difference between
+** sqlite3LocateTable() and this function is that this function restricts
+** the search to schema (p->pSchema) if it is not NULL. p->pSchema may be
+** non-NULL if it is part of a view or trigger program definition. See
+** sqlite3FixSrcList() for details.
+*/
+SQLITE_PRIVATE Table *sqlite3LocateTableItem(
+  Parse *pParse,
+  u32 flags,
+  SrcItem *p
+){
+  const char *zDb;
+  if( p->fg.fixedSchema ){
+    int iDb = sqlite3SchemaToIndex(pParse->db, p->u4.pSchema);
+    zDb = pParse->db->aDb[iDb].zDbSName;
+  }else{
+    assert( !p->fg.isSubquery );
+    zDb = p->u4.zDatabase;
+  }
+  return sqlite3LocateTable(pParse, flags, p->zName, zDb);
+}
+
+/*
+** Return the preferred table name for system tables.  Translate legacy
+** names into the new preferred names, as appropriate.
+*/
+SQLITE_PRIVATE const char *sqlite3PreferredTableName(const char *zName){
+  if( sqlite3StrNICmp(zName, "sqlite_", 7)==0 ){
+    if( sqlite3StrICmp(zName+7, &LEGACY_SCHEMA_TABLE[7])==0 ){
+      return PREFERRED_SCHEMA_TABLE;
+    }
+    if( sqlite3StrICmp(zName+7, &LEGACY_TEMP_SCHEMA_TABLE[7])==0 ){
+      return PREFERRED_TEMP_SCHEMA_TABLE;
+    }
+  }
+  return zName;
+}
+
+/*
+** Locate the in-memory structure that describes
+** a particular index given the name of that index
+** and the name of the database that contains the index.
+** Return NULL if not found.
+**
+** If zDatabase is 0, all databases are searched for the
+** table and the first matching index is returned.  (No checking
+** for duplicate index names is done.)  The search order is
+** TEMP first, then MAIN, then any auxiliary databases added
+** using the ATTACH command.
+*/
+SQLITE_PRIVATE Index *sqlite3FindIndex(sqlite3 *db, const char *zName, const char *zDb){
+  Index *p = 0;
+  int i;
+  /* All mutexes are required for schema access.  Make sure we hold them. */
+  assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );
+  for(i=OMIT_TEMPDB; i<db->nDb; i++){
+    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
+    Schema *pSchema = db->aDb[j].pSchema;
+    assert( pSchema );
+    if( zDb && sqlite3DbIsNamed(db, j, zDb)==0 ) continue;
+    assert( sqlite3SchemaMutexHeld(db, j, 0) );
+    p = sqlite3HashFind(&pSchema->idxHash, zName);
+    if( p ) break;
+  }
+  return p;
+}
+
+/*
+** Reclaim the memory used by an index
+*/
+SQLITE_PRIVATE void sqlite3FreeIndex(sqlite3 *db, Index *p){
+#ifndef SQLITE_OMIT_ANALYZE
+  sqlite3DeleteIndexSamples(db, p);
+#endif
+  sqlite3ExprDelete(db, p->pPartIdxWhere);
+  sqlite3ExprListDelete(db, p->aColExpr);
+  sqlite3DbFree(db, p->zColAff);
+  if( p->isResized ) sqlite3DbFree(db, (void *)p->azColl);
+#ifdef SQLITE_ENABLE_STAT4
+  sqlite3_free(p->aiRowEst);
+#endif
+  sqlite3DbFree(db, p);
+}
+
+/*
+** For the index called zIdxName which is found in the database iDb,
+** unlike that index from its Table then remove the index from
+** the index hash table and free all memory structures associated
+** with the index.
+*/
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteIndex(sqlite3 *db, int iDb, const char *zIdxName){
+  Index *pIndex;
+  Hash *pHash;
+
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  pHash = &db->aDb[iDb].pSchema->idxHash;
+  pIndex = sqlite3HashInsert(pHash, zIdxName, 0);
+  if( ALWAYS(pIndex) ){
+    if( pIndex->pTable->pIndex==pIndex ){
+      pIndex->pTable->pIndex = pIndex->pNext;
+    }else{
+      Index *p;
+      /* Justification of ALWAYS();  The index must be on the list of
+      ** indices. */
+      p = pIndex->pTable->pIndex;
+      while( ALWAYS(p) && p->pNext!=pIndex ){ p = p->pNext; }
+      if( ALWAYS(p && p->pNext==pIndex) ){
+        p->pNext = pIndex->pNext;
+      }
+    }
+    sqlite3FreeIndex(db, pIndex);
+  }
+  db->mDbFlags |= DBFLAG_SchemaChange;
+}
+
+/*
+** Look through the list of open database files in db->aDb[] and if
+** any have been closed, remove them from the list.  Reallocate the
+** db->aDb[] structure to a smaller size, if possible.
+**
+** Entry 0 (the "main" database) and entry 1 (the "temp" database)
+** are never candidates for being collapsed.
+*/
+SQLITE_PRIVATE void sqlite3CollapseDatabaseArray(sqlite3 *db){
+  int i, j;
+  for(i=j=2; i<db->nDb; i++){
+    struct Db *pDb = &db->aDb[i];
+    if( pDb->pBt==0 ){
+      sqlite3DbFree(db, pDb->zDbSName);
+      pDb->zDbSName = 0;
+      continue;
+    }
+    if( j<i ){
+      db->aDb[j] = db->aDb[i];
+    }
+    j++;
+  }
+  db->nDb = j;
+  if( db->nDb<=2 && db->aDb!=db->aDbStatic ){
+    memcpy(db->aDbStatic, db->aDb, 2*sizeof(db->aDb[0]));
+    sqlite3DbFree(db, db->aDb);
+    db->aDb = db->aDbStatic;
+  }
+}
+
+/*
+** Reset the schema for the database at index iDb.  Also reset the
+** TEMP schema.  The reset is deferred if db->nSchemaLock is not zero.
+** Deferred resets may be run by calling with iDb<0.
+*/
+SQLITE_PRIVATE void sqlite3ResetOneSchema(sqlite3 *db, int iDb){
+  int i;
+  assert( iDb<db->nDb );
+
+  if( iDb>=0 ){
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    DbSetProperty(db, iDb, DB_ResetWanted);
+    DbSetProperty(db, 1, DB_ResetWanted);
+    db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
+  }
+
+  if( db->nSchemaLock==0 ){
+    for(i=0; i<db->nDb; i++){
+      if( DbHasProperty(db, i, DB_ResetWanted) ){
+        sqlite3SchemaClear(db->aDb[i].pSchema);
+      }
+    }
+  }
+}
+
+/*
+** Erase all schema information from all attached databases (including
+** "main" and "temp") for a single database connection.
+*/
+SQLITE_PRIVATE void sqlite3ResetAllSchemasOfConnection(sqlite3 *db){
+  int i;
+  sqlite3BtreeEnterAll(db);
+  for(i=0; i<db->nDb; i++){
+    Db *pDb = &db->aDb[i];
+    if( pDb->pSchema ){
+      if( db->nSchemaLock==0 ){
+        sqlite3SchemaClear(pDb->pSchema);
+      }else{
+        DbSetProperty(db, i, DB_ResetWanted);
+      }
+    }
+  }
+  db->mDbFlags &= ~(DBFLAG_SchemaChange|DBFLAG_SchemaKnownOk);
+  sqlite3VtabUnlockList(db);
+  sqlite3BtreeLeaveAll(db);
+  if( db->nSchemaLock==0 ){
+    sqlite3CollapseDatabaseArray(db);
+  }
+}
+
+/*
+** This routine is called when a commit occurs.
+*/
+SQLITE_PRIVATE void sqlite3CommitInternalChanges(sqlite3 *db){
+  db->mDbFlags &= ~DBFLAG_SchemaChange;
+}
+
+/*
+** Set the expression associated with a column.  This is usually
+** the DEFAULT value, but might also be the expression that computes
+** the value for a generated column.
+*/
+SQLITE_PRIVATE void sqlite3ColumnSetExpr(
+  Parse *pParse,    /* Parsing context */
+  Table *pTab,      /* The table containing the column */
+  Column *pCol,     /* The column to receive the new DEFAULT expression */
+  Expr *pExpr       /* The new default expression */
+){
+  ExprList *pList;
+  assert( IsOrdinaryTable(pTab) );
+  pList = pTab->u.tab.pDfltList;
+  if( pCol->iDflt==0
+   || NEVER(pList==0)
+   || NEVER(pList->nExpr<pCol->iDflt)
+  ){
+    pCol->iDflt = pList==0 ? 1 : pList->nExpr+1;
+    pTab->u.tab.pDfltList = sqlite3ExprListAppend(pParse, pList, pExpr);
+  }else{
+    sqlite3ExprDelete(pParse->db, pList->a[pCol->iDflt-1].pExpr);
+    pList->a[pCol->iDflt-1].pExpr = pExpr;
+  }
+}
+
+/*
+** Return the expression associated with a column.  The expression might be
+** the DEFAULT clause or the AS clause of a generated column.
+** Return NULL if the column has no associated expression.
+*/
+SQLITE_PRIVATE Expr *sqlite3ColumnExpr(Table *pTab, Column *pCol){
+  if( pCol->iDflt==0 ) return 0;
+  if( !IsOrdinaryTable(pTab) ) return 0;
+  if( NEVER(pTab->u.tab.pDfltList==0) ) return 0;
+  if( NEVER(pTab->u.tab.pDfltList->nExpr<pCol->iDflt) ) return 0;
+  return pTab->u.tab.pDfltList->a[pCol->iDflt-1].pExpr;
+}
+
+/*
+** Set the collating sequence name for a column.
+*/
+SQLITE_PRIVATE void sqlite3ColumnSetColl(
+  sqlite3 *db,
+  Column *pCol,
+  const char *zColl
+){
+  i64 nColl;
+  i64 n;
+  char *zNew;
+  assert( zColl!=0 );
+  n = sqlite3Strlen30(pCol->zCnName) + 1;
+  if( pCol->colFlags & COLFLAG_HASTYPE ){
+    n += sqlite3Strlen30(pCol->zCnName+n) + 1;
+  }
+  nColl = sqlite3Strlen30(zColl) + 1;
+  zNew = sqlite3DbRealloc(db, pCol->zCnName, nColl+n);
+  if( zNew ){
+    pCol->zCnName = zNew;
+    memcpy(pCol->zCnName + n, zColl, nColl);
+    pCol->colFlags |= COLFLAG_HASCOLL;
+  }
+}
+
+/*
+** Return the collating sequence name for a column
+*/
+SQLITE_PRIVATE const char *sqlite3ColumnColl(Column *pCol){
+  const char *z;
+  if( (pCol->colFlags & COLFLAG_HASCOLL)==0 ) return 0;
+  z = pCol->zCnName;
+  while( *z ){ z++; }
+  if( pCol->colFlags & COLFLAG_HASTYPE ){
+    do{ z++; }while( *z );
+  }
+  return z+1;
+}
+
+/*
+** Delete memory allocated for the column names of a table or view (the
+** Table.aCol[] array).
+*/
+SQLITE_PRIVATE void sqlite3DeleteColumnNames(sqlite3 *db, Table *pTable){
+  int i;
+  Column *pCol;
+  assert( pTable!=0 );
+  assert( db!=0 );
+  if( (pCol = pTable->aCol)!=0 ){
+    for(i=0; i<pTable->nCol; i++, pCol++){
+      assert( pCol->zCnName==0 || pCol->hName==sqlite3StrIHash(pCol->zCnName) );
+      sqlite3DbFree(db, pCol->zCnName);
+    }
+    sqlite3DbNNFreeNN(db, pTable->aCol);
+    if( IsOrdinaryTable(pTable) ){
+      sqlite3ExprListDelete(db, pTable->u.tab.pDfltList);
+    }
+    if( db->pnBytesFreed==0 ){
+      pTable->aCol = 0;
+      pTable->nCol = 0;
+      if( IsOrdinaryTable(pTable) ){
+        pTable->u.tab.pDfltList = 0;
+      }
+    }
+  }
+}
+
+/*
+** Remove the memory data structures associated with the given
+** Table.  No changes are made to disk by this routine.
+**
+** This routine just deletes the data structure.  It does not unlink
+** the table data structure from the hash table.  But it does destroy
+** memory structures of the indices and foreign keys associated with
+** the table.
+**
+** The db parameter is optional.  It is needed if the Table object
+** contains lookaside memory.  (Table objects in the schema do not use
+** lookaside memory, but some ephemeral Table objects do.)  Or the
+** db parameter can be used with db->pnBytesFreed to measure the memory
+** used by the Table object.
+*/
+static void SQLITE_NOINLINE deleteTable(sqlite3 *db, Table *pTable){
+  Index *pIndex, *pNext;
+
+#ifdef SQLITE_DEBUG
+  /* Record the number of outstanding lookaside allocations in schema Tables
+  ** prior to doing any free() operations. Since schema Tables do not use
+  ** lookaside, this number should not change.
+  **
+  ** If malloc has already failed, it may be that it failed while allocating
+  ** a Table object that was going to be marked ephemeral. So do not check
+  ** that no lookaside memory is used in this case either. */
+  int nLookaside = 0;
+  assert( db!=0 );
+  if( !db->mallocFailed && (pTable->tabFlags & TF_Ephemeral)==0 ){
+    nLookaside = sqlite3LookasideUsed(db, 0);
+  }
+#endif
+
+  /* Delete all indices associated with this table. */
+  for(pIndex = pTable->pIndex; pIndex; pIndex=pNext){
+    pNext = pIndex->pNext;
+    assert( pIndex->pSchema==pTable->pSchema
+         || (IsVirtual(pTable) && pIndex->idxType!=SQLITE_IDXTYPE_APPDEF) );
+    if( db->pnBytesFreed==0 && !IsVirtual(pTable) ){
+      char *zName = pIndex->zName;
+      TESTONLY ( Index *pOld = ) sqlite3HashInsert(
+         &pIndex->pSchema->idxHash, zName, 0
+      );
+      assert( db==0 || sqlite3SchemaMutexHeld(db, 0, pIndex->pSchema) );
+      assert( pOld==pIndex || pOld==0 );
+    }
+    sqlite3FreeIndex(db, pIndex);
+  }
+
+  if( IsOrdinaryTable(pTable) ){
+    sqlite3FkDelete(db, pTable);
+  }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  else if( IsVirtual(pTable) ){
+    sqlite3VtabClear(db, pTable);
+  }
+#endif
+  else{
+    assert( IsView(pTable) );
+    sqlite3SelectDelete(db, pTable->u.view.pSelect);
+  }
+
+  /* Delete the Table structure itself.
+  */
+  sqlite3DeleteColumnNames(db, pTable);
+  sqlite3DbFree(db, pTable->zName);
+  sqlite3DbFree(db, pTable->zColAff);
+  sqlite3ExprListDelete(db, pTable->pCheck);
+  sqlite3DbFree(db, pTable);
+
+  /* Verify that no lookaside memory was used by schema tables */
+  assert( nLookaside==0 || nLookaside==sqlite3LookasideUsed(db,0) );
+}
+SQLITE_PRIVATE void sqlite3DeleteTable(sqlite3 *db, Table *pTable){
+  /* Do not delete the table until the reference count reaches zero. */
+  assert( db!=0 );
+  if( !pTable ) return;
+  if( db->pnBytesFreed==0 && (--pTable->nTabRef)>0 ) return;
+  deleteTable(db, pTable);
+}
+SQLITE_PRIVATE void sqlite3DeleteTableGeneric(sqlite3 *db, void *pTable){
+  sqlite3DeleteTable(db, (Table*)pTable);
+}
+
+
+/*
+** Unlink the given table from the hash tables and the delete the
+** table structure with all its indices and foreign keys.
+*/
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTable(sqlite3 *db, int iDb, const char *zTabName){
+  Table *p;
+  Db *pDb;
+
+  assert( db!=0 );
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( zTabName );
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  testcase( zTabName[0]==0 );  /* Zero-length table names are allowed */
+  pDb = &db->aDb[iDb];
+  p = sqlite3HashInsert(&pDb->pSchema->tblHash, zTabName, 0);
+  sqlite3DeleteTable(db, p);
+  db->mDbFlags |= DBFLAG_SchemaChange;
+}
+
+/*
+** Given a token, return a string that consists of the text of that
+** token.  Space to hold the returned string
+** is obtained from sqliteMalloc() and must be freed by the calling
+** function.
+**
+** Any quotation marks (ex:  "name", 'name', [name], or `name`) that
+** surround the body of the token are removed.
+**
+** Tokens are often just pointers into the original SQL text and so
+** are not \000 terminated and are not persistent.  The returned string
+** is \000 terminated and is persistent.
+*/
+SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3 *db, const Token *pName){
+  char *zName;
+  if( pName ){
+    zName = sqlite3DbStrNDup(db, (const char*)pName->z, pName->n);
+    sqlite3Dequote(zName);
+  }else{
+    zName = 0;
+  }
+  return zName;
+}
+
+/*
+** Open the sqlite_schema table stored in database number iDb for
+** writing. The table is opened using cursor 0.
+*/
+SQLITE_PRIVATE void sqlite3OpenSchemaTable(Parse *p, int iDb){
+  Vdbe *v = sqlite3GetVdbe(p);
+  sqlite3TableLock(p, iDb, SCHEMA_ROOT, 1, LEGACY_SCHEMA_TABLE);
+  sqlite3VdbeAddOp4Int(v, OP_OpenWrite, 0, SCHEMA_ROOT, iDb, 5);
+  if( p->nTab==0 ){
+    p->nTab = 1;
+  }
+}
+
+/*
+** Parameter zName points to a nul-terminated buffer containing the name
+** of a database ("main", "temp" or the name of an attached db). This
+** function returns the index of the named database in db->aDb[], or
+** -1 if the named db cannot be found.
+*/
+SQLITE_PRIVATE int sqlite3FindDbName(sqlite3 *db, const char *zName){
+  int i = -1;         /* Database number */
+  if( zName ){
+    Db *pDb;
+    for(i=(db->nDb-1), pDb=&db->aDb[i]; i>=0; i--, pDb--){
+      if( 0==sqlite3_stricmp(pDb->zDbSName, zName) ) break;
+      /* "main" is always an acceptable alias for the primary database
+      ** even if it has been renamed using SQLITE_DBCONFIG_MAINDBNAME. */
+      if( i==0 && 0==sqlite3_stricmp("main", zName) ) break;
+    }
+  }
+  return i;
+}
+
+/*
+** The token *pName contains the name of a database (either "main" or
+** "temp" or the name of an attached db). This routine returns the
+** index of the named database in db->aDb[], or -1 if the named db
+** does not exist.
+*/
+SQLITE_PRIVATE int sqlite3FindDb(sqlite3 *db, Token *pName){
+  int i;                               /* Database number */
+  char *zName;                         /* Name we are searching for */
+  zName = sqlite3NameFromToken(db, pName);
+  i = sqlite3FindDbName(db, zName);
+  sqlite3DbFree(db, zName);
+  return i;
+}
+
+/* The table or view or trigger name is passed to this routine via tokens
+** pName1 and pName2. If the table name was fully qualified, for example:
+**
+** CREATE TABLE xxx.yyy (...);
+**
+** Then pName1 is set to "xxx" and pName2 "yyy". On the other hand if
+** the table name is not fully qualified, i.e.:
+**
+** CREATE TABLE yyy(...);
+**
+** Then pName1 is set to "yyy" and pName2 is "".
+**
+** This routine sets the *ppUnqual pointer to point at the token (pName1 or
+** pName2) that stores the unqualified table name.  The index of the
+** database "xxx" is returned.
+*/
+SQLITE_PRIVATE int sqlite3TwoPartName(
+  Parse *pParse,      /* Parsing and code generating context */
+  Token *pName1,      /* The "xxx" in the name "xxx.yyy" or "xxx" */
+  Token *pName2,      /* The "yyy" in the name "xxx.yyy" */
+  Token **pUnqual     /* Write the unqualified object name here */
+){
+  int iDb;                    /* Database holding the object */
+  sqlite3 *db = pParse->db;
+
+  assert( pName2!=0 );
+  if( pName2->n>0 ){
+    if( db->init.busy ) {
+      sqlite3ErrorMsg(pParse, "corrupt database");
+      return -1;
+    }
+    *pUnqual = pName2;
+    iDb = sqlite3FindDb(db, pName1);
+    if( iDb<0 ){
+      sqlite3ErrorMsg(pParse, "unknown database %T", pName1);
+      return -1;
+    }
+  }else{
+    assert( db->init.iDb==0 || db->init.busy || IN_SPECIAL_PARSE
+             || (db->mDbFlags & DBFLAG_Vacuum)!=0);
+    iDb = db->init.iDb;
+    *pUnqual = pName1;
+  }
+  return iDb;
+}
+
+/*
+** True if PRAGMA writable_schema is ON
+*/
+SQLITE_PRIVATE int sqlite3WritableSchema(sqlite3 *db){
+  testcase( (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==0 );
+  testcase( (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==
+               SQLITE_WriteSchema );
+  testcase( (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==
+               SQLITE_Defensive );
+  testcase( (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==
+               (SQLITE_WriteSchema|SQLITE_Defensive) );
+  return (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==SQLITE_WriteSchema;
+}
+
+/*
+** This routine is used to check if the UTF-8 string zName is a legal
+** unqualified name for a new schema object (table, index, view or
+** trigger). All names are legal except those that begin with the string
+** "sqlite_" (in upper, lower or mixed case). This portion of the namespace
+** is reserved for internal use.
+**
+** When parsing the sqlite_schema table, this routine also checks to
+** make sure the "type", "name", and "tbl_name" columns are consistent
+** with the SQL.
+*/
+SQLITE_PRIVATE int sqlite3CheckObjectName(
+  Parse *pParse,            /* Parsing context */
+  const char *zName,        /* Name of the object to check */
+  const char *zType,        /* Type of this object */
+  const char *zTblName      /* Parent table name for triggers and indexes */
+){
+  sqlite3 *db = pParse->db;
+  if( sqlite3WritableSchema(db)
+   || db->init.imposterTable
+   || !sqlite3Config.bExtraSchemaChecks
+  ){
+    /* Skip these error checks for writable_schema=ON */
+    return SQLITE_OK;
+  }
+  if( db->init.busy ){
+    if( sqlite3_stricmp(zType, db->init.azInit[0])
+     || sqlite3_stricmp(zName, db->init.azInit[1])
+     || sqlite3_stricmp(zTblName, db->init.azInit[2])
+    ){
+      sqlite3ErrorMsg(pParse, ""); /* corruptSchema() will supply the error */
+      return SQLITE_ERROR;
+    }
+  }else{
+    if( (pParse->nested==0 && 0==sqlite3StrNICmp(zName, "sqlite_", 7))
+     || (sqlite3ReadOnlyShadowTables(db) && sqlite3ShadowTableName(db, zName))
+    ){
+      sqlite3ErrorMsg(pParse, "object name reserved for internal use: %s",
+                      zName);
+      return SQLITE_ERROR;
+    }
+
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return the PRIMARY KEY index of a table
+*/
+SQLITE_PRIVATE Index *sqlite3PrimaryKeyIndex(Table *pTab){
+  Index *p;
+  for(p=pTab->pIndex; p && !IsPrimaryKeyIndex(p); p=p->pNext){}
+  return p;
+}
+
+/*
+** Convert an table column number into a index column number.  That is,
+** for the column iCol in the table (as defined by the CREATE TABLE statement)
+** find the (first) offset of that column in index pIdx.  Or return -1
+** if column iCol is not used in index pIdx.
+*/
+SQLITE_PRIVATE i16 sqlite3TableColumnToIndex(Index *pIdx, i16 iCol){
+  int i;
+  for(i=0; i<pIdx->nColumn; i++){
+    if( iCol==pIdx->aiColumn[i] ) return i;
+  }
+  return -1;
+}
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+/* Convert a storage column number into a table column number.
+**
+** The storage column number (0,1,2,....) is the index of the value
+** as it appears in the record on disk.  The true column number
+** is the index (0,1,2,...) of the column in the CREATE TABLE statement.
+**
+** The storage column number is less than the table column number if
+** and only there are VIRTUAL columns to the left.
+**
+** If SQLITE_OMIT_GENERATED_COLUMNS, this routine is a no-op macro.
+*/
+SQLITE_PRIVATE i16 sqlite3StorageColumnToTable(Table *pTab, i16 iCol){
+  if( pTab->tabFlags & TF_HasVirtual ){
+    int i;
+    for(i=0; i<=iCol; i++){
+      if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ) iCol++;
+    }
+  }
+  return iCol;
+}
+#endif
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+/* Convert a table column number into a storage column number.
+**
+** The storage column number (0,1,2,....) is the index of the value
+** as it appears in the record on disk.  Or, if the input column is
+** the N-th virtual column (zero-based) then the storage number is
+** the number of non-virtual columns in the table plus N.
+**
+** The true column number is the index (0,1,2,...) of the column in
+** the CREATE TABLE statement.
+**
+** If the input column is a VIRTUAL column, then it should not appear
+** in storage.  But the value sometimes is cached in registers that
+** follow the range of registers used to construct storage.  This
+** avoids computing the same VIRTUAL column multiple times, and provides
+** values for use by OP_Param opcodes in triggers.  Hence, if the
+** input column is a VIRTUAL table, put it after all the other columns.
+**
+** In the following, N means "normal column", S means STORED, and
+** V means VIRTUAL.  Suppose the CREATE TABLE has columns like this:
+**
+**        CREATE TABLE ex(N,S,V,N,S,V,N,S,V);
+**                     -- 0 1 2 3 4 5 6 7 8
+**
+** Then the mapping from this function is as follows:
+**
+**    INPUTS:     0 1 2 3 4 5 6 7 8
+**    OUTPUTS:    0 1 6 2 3 7 4 5 8
+**
+** So, in other words, this routine shifts all the virtual columns to
+** the end.
+**
+** If SQLITE_OMIT_GENERATED_COLUMNS then there are no virtual columns and
+** this routine is a no-op macro.  If the pTab does not have any virtual
+** columns, then this routine is no-op that always return iCol.  If iCol
+** is negative (indicating the ROWID column) then this routine return iCol.
+*/
+SQLITE_PRIVATE i16 sqlite3TableColumnToStorage(Table *pTab, i16 iCol){
+  int i;
+  i16 n;
+  assert( iCol<pTab->nCol );
+  if( (pTab->tabFlags & TF_HasVirtual)==0 || iCol<0 ) return iCol;
+  for(i=0, n=0; i<iCol; i++){
+    if( (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0 ) n++;
+  }
+  if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ){
+    /* iCol is a virtual column itself */
+    return pTab->nNVCol + i - n;
+  }else{
+    /* iCol is a normal or stored column */
+    return n;
+  }
+}
+#endif
+
+/*
+** Insert a single OP_JournalMode query opcode in order to force the
+** prepared statement to return false for sqlite3_stmt_readonly().  This
+** is used by CREATE TABLE IF NOT EXISTS and similar if the table already
+** exists, so that the prepared statement for CREATE TABLE IF NOT EXISTS
+** will return false for sqlite3_stmt_readonly() even if that statement
+** is a read-only no-op.
+*/
+static void sqlite3ForceNotReadOnly(Parse *pParse){
+  int iReg = ++pParse->nMem;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp3(v, OP_JournalMode, 0, iReg, PAGER_JOURNALMODE_QUERY);
+    sqlite3VdbeUsesBtree(v, 0);
+  }
+}
+
+/*
+** Begin constructing a new table representation in memory.  This is
+** the first of several action routines that get called in response
+** to a CREATE TABLE statement.  In particular, this routine is called
+** after seeing tokens "CREATE" and "TABLE" and the table name. The isTemp
+** flag is true if the table should be stored in the auxiliary database
+** file instead of in the main database file.  This is normally the case
+** when the "TEMP" or "TEMPORARY" keyword occurs in between
+** CREATE and TABLE.
+**
+** The new table record is initialized and put in pParse->pNewTable.
+** As more of the CREATE TABLE statement is parsed, additional action
+** routines will be called to add more information to this record.
+** At the end of the CREATE TABLE statement, the sqlite3EndTable() routine
+** is called to complete the construction of the new table record.
+*/
+SQLITE_PRIVATE void sqlite3StartTable(
+  Parse *pParse,   /* Parser context */
+  Token *pName1,   /* First part of the name of the table or view */
+  Token *pName2,   /* Second part of the name of the table or view */
+  int isTemp,      /* True if this is a TEMP table */
+  int isView,      /* True if this is a VIEW */
+  int isVirtual,   /* True if this is a VIRTUAL table */
+  int noErr        /* Do nothing if table already exists */
+){
+  Table *pTable;
+  char *zName = 0; /* The name of the new table */
+  sqlite3 *db = pParse->db;
+  Vdbe *v;
+  int iDb;         /* Database number to create the table in */
+  Token *pName;    /* Unqualified name of the table to create */
+
+  if( db->init.busy && db->init.newTnum==1 ){
+    /* Special case:  Parsing the sqlite_schema or sqlite_temp_schema schema */
+    iDb = db->init.iDb;
+    zName = sqlite3DbStrDup(db, SCHEMA_TABLE(iDb));
+    pName = pName1;
+  }else{
+    /* The common case */
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+    if( iDb<0 ) return;
+    if( !OMIT_TEMPDB && isTemp && pName2->n>0 && iDb!=1 ){
+      /* If creating a temp table, the name may not be qualified. Unless
+      ** the database name is "temp" anyway.  */
+      sqlite3ErrorMsg(pParse, "temporary table name must be unqualified");
+      return;
+    }
+    if( !OMIT_TEMPDB && isTemp ) iDb = 1;
+    zName = sqlite3NameFromToken(db, pName);
+    if( IN_RENAME_OBJECT ){
+      sqlite3RenameTokenMap(pParse, (void*)zName, pName);
+    }
+  }
+  pParse->sNameToken = *pName;
+  if( zName==0 ) return;
+  if( sqlite3CheckObjectName(pParse, zName, isView?"view":"table", zName) ){
+    goto begin_table_error;
+  }
+  if( db->init.iDb==1 ) isTemp = 1;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  assert( isTemp==0 || isTemp==1 );
+  assert( isView==0 || isView==1 );
+  {
+    static const u8 aCode[] = {
+       SQLITE_CREATE_TABLE,
+       SQLITE_CREATE_TEMP_TABLE,
+       SQLITE_CREATE_VIEW,
+       SQLITE_CREATE_TEMP_VIEW
+    };
+    char *zDb = db->aDb[iDb].zDbSName;
+    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(isTemp), 0, zDb) ){
+      goto begin_table_error;
+    }
+    if( !isVirtual && sqlite3AuthCheck(pParse, (int)aCode[isTemp+2*isView],
+                                       zName, 0, zDb) ){
+      goto begin_table_error;
+    }
+  }
+#endif
+
+  /* Make sure the new table name does not collide with an existing
+  ** index or table name in the same database.  Issue an error message if
+  ** it does. The exception is if the statement being parsed was passed
+  ** to an sqlite3_declare_vtab() call. In that case only the column names
+  ** and types will be used, so there is no need to test for namespace
+  ** collisions.
+  */
+  if( !IN_SPECIAL_PARSE ){
+    char *zDb = db->aDb[iDb].zDbSName;
+    if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+      goto begin_table_error;
+    }
+    pTable = sqlite3FindTable(db, zName, zDb);
+    if( pTable ){
+      if( !noErr ){
+        sqlite3ErrorMsg(pParse, "%s %T already exists",
+                        (IsView(pTable)? "view" : "table"), pName);
+      }else{
+        assert( !db->init.busy || CORRUPT_DB );
+        sqlite3CodeVerifySchema(pParse, iDb);
+        sqlite3ForceNotReadOnly(pParse);
+      }
+      goto begin_table_error;
+    }
+    if( sqlite3FindIndex(db, zName, zDb)!=0 ){
+      sqlite3ErrorMsg(pParse, "there is already an index named %s", zName);
+      goto begin_table_error;
+    }
+  }
+
+  pTable = sqlite3DbMallocZero(db, sizeof(Table));
+  if( pTable==0 ){
+    assert( db->mallocFailed );
+    pParse->rc = SQLITE_NOMEM_BKPT;
+    pParse->nErr++;
+    goto begin_table_error;
+  }
+  pTable->zName = zName;
+  pTable->iPKey = -1;
+  pTable->pSchema = db->aDb[iDb].pSchema;
+  pTable->nTabRef = 1;
+#ifdef SQLITE_DEFAULT_ROWEST
+  pTable->nRowLogEst = sqlite3LogEst(SQLITE_DEFAULT_ROWEST);
+#else
+  pTable->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
+#endif
+  assert( pParse->pNewTable==0 );
+  pParse->pNewTable = pTable;
+
+  /* Begin generating the code that will insert the table record into
+  ** the schema table.  Note in particular that we must go ahead
+  ** and allocate the record number for the table entry now.  Before any
+  ** PRIMARY KEY or UNIQUE keywords are parsed.  Those keywords will cause
+  ** indices to be created and the table record must come before the
+  ** indices.  Hence, the record number for the table must be allocated
+  ** now.
+  */
+  if( !db->init.busy && (v = sqlite3GetVdbe(pParse))!=0 ){
+    int addr1;
+    int fileFormat;
+    int reg1, reg2, reg3;
+    /* nullRow[] is an OP_Record encoding of a row containing 5 NULLs */
+    static const char nullRow[] = { 6, 0, 0, 0, 0, 0 };
+    sqlite3BeginWriteOperation(pParse, 1, iDb);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( isVirtual ){
+      sqlite3VdbeAddOp0(v, OP_VBegin);
+    }
+#endif
+
+    /* If the file format and encoding in the database have not been set,
+    ** set them now.
+    */
+    reg1 = pParse->regRowid = ++pParse->nMem;
+    reg2 = pParse->regRoot = ++pParse->nMem;
+    reg3 = ++pParse->nMem;
+    sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, reg3, BTREE_FILE_FORMAT);
+    sqlite3VdbeUsesBtree(v, iDb);
+    addr1 = sqlite3VdbeAddOp1(v, OP_If, reg3); VdbeCoverage(v);
+    fileFormat = (db->flags & SQLITE_LegacyFileFmt)!=0 ?
+                  1 : SQLITE_MAX_FILE_FORMAT;
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, fileFormat);
+    sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_TEXT_ENCODING, ENC(db));
+    sqlite3VdbeJumpHere(v, addr1);
+
+    /* This just creates a place-holder record in the sqlite_schema table.
+    ** The record created does not contain anything yet.  It will be replaced
+    ** by the real entry in code generated at sqlite3EndTable().
+    **
+    ** The rowid for the new entry is left in register pParse->regRowid.
+    ** The root page number of the new table is left in reg pParse->regRoot.
+    ** The rowid and root page number values are needed by the code that
+    ** sqlite3EndTable will generate.
+    */
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+    if( isView || isVirtual ){
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, reg2);
+    }else
+#endif
+    {
+      assert( !pParse->bReturning );
+      pParse->u1.addrCrTab =
+         sqlite3VdbeAddOp3(v, OP_CreateBtree, iDb, reg2, BTREE_INTKEY);
+    }
+    sqlite3OpenSchemaTable(pParse, iDb);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, 0, reg1);
+    sqlite3VdbeAddOp4(v, OP_Blob, 6, reg3, 0, nullRow, P4_STATIC);
+    sqlite3VdbeAddOp3(v, OP_Insert, 0, reg3, reg1);
+    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+    sqlite3VdbeAddOp0(v, OP_Close);
+  }
+
+  /* Normal (non-error) return. */
+  return;
+
+  /* If an error occurs, we jump here */
+begin_table_error:
+  pParse->checkSchema = 1;
+  sqlite3DbFree(db, zName);
+  return;
+}
+
+/* Set properties of a table column based on the (magical)
+** name of the column.
+*/
+#if SQLITE_ENABLE_HIDDEN_COLUMNS
+SQLITE_PRIVATE void sqlite3ColumnPropertiesFromName(Table *pTab, Column *pCol){
+  if( sqlite3_strnicmp(pCol->zCnName, "__hidden__", 10)==0 ){
+    pCol->colFlags |= COLFLAG_HIDDEN;
+    if( pTab ) pTab->tabFlags |= TF_HasHidden;
+  }else if( pTab && pCol!=pTab->aCol && (pCol[-1].colFlags & COLFLAG_HIDDEN) ){
+    pTab->tabFlags |= TF_OOOHidden;
+  }
+}
+#endif
+
+/*
+** Clean up the data structures associated with the RETURNING clause.
+*/
+static void sqlite3DeleteReturning(sqlite3 *db, void *pArg){
+  Returning *pRet = (Returning*)pArg;
+  Hash *pHash;
+  pHash = &(db->aDb[1].pSchema->trigHash);
+  sqlite3HashInsert(pHash, pRet->zName, 0);
+  sqlite3ExprListDelete(db, pRet->pReturnEL);
+  sqlite3DbFree(db, pRet);
+}
+
+/*
+** Add the RETURNING clause to the parse currently underway.
+**
+** This routine creates a special TEMP trigger that will fire for each row
+** of the DML statement.  That TEMP trigger contains a single SELECT
+** statement with a result set that is the argument of the RETURNING clause.
+** The trigger has the Trigger.bReturning flag and an opcode of
+** TK_RETURNING instead of TK_SELECT, so that the trigger code generator
+** knows to handle it specially.  The TEMP trigger is automatically
+** removed at the end of the parse.
+**
+** When this routine is called, we do not yet know if the RETURNING clause
+** is attached to a DELETE, INSERT, or UPDATE, so construct it as a
+** RETURNING trigger instead.  It will then be converted into the appropriate
+** type on the first call to sqlite3TriggersExist().
+*/
+SQLITE_PRIVATE void sqlite3AddReturning(Parse *pParse, ExprList *pList){
+  Returning *pRet;
+  Hash *pHash;
+  sqlite3 *db = pParse->db;
+  if( pParse->pNewTrigger ){
+    sqlite3ErrorMsg(pParse, "cannot use RETURNING in a trigger");
+  }else{
+    assert( pParse->bReturning==0 || pParse->ifNotExists );
+  }
+  pParse->bReturning = 1;
+  pRet = sqlite3DbMallocZero(db, sizeof(*pRet));
+  if( pRet==0 ){
+    sqlite3ExprListDelete(db, pList);
+    return;
+  }
+  pParse->u1.pReturning = pRet;
+  pRet->pParse = pParse;
+  pRet->pReturnEL = pList;
+  sqlite3ParserAddCleanup(pParse, sqlite3DeleteReturning, pRet);
+  testcase( pParse->earlyCleanup );
+  if( db->mallocFailed ) return;
+  sqlite3_snprintf(sizeof(pRet->zName), pRet->zName,
+                   "sqlite_returning_%p", pParse);
+  pRet->retTrig.zName = pRet->zName;
+  pRet->retTrig.op = TK_RETURNING;
+  pRet->retTrig.tr_tm = TRIGGER_AFTER;
+  pRet->retTrig.bReturning = 1;
+  pRet->retTrig.pSchema = db->aDb[1].pSchema;
+  pRet->retTrig.pTabSchema = db->aDb[1].pSchema;
+  pRet->retTrig.step_list = &pRet->retTStep;
+  pRet->retTStep.op = TK_RETURNING;
+  pRet->retTStep.pTrig = &pRet->retTrig;
+  pRet->retTStep.pExprList = pList;
+  pHash = &(db->aDb[1].pSchema->trigHash);
+  assert( sqlite3HashFind(pHash, pRet->zName)==0
+          || pParse->nErr  || pParse->ifNotExists );
+  if( sqlite3HashInsert(pHash, pRet->zName, &pRet->retTrig)
+          ==&pRet->retTrig ){
+    sqlite3OomFault(db);
+  }
+}
+
+/*
+** Add a new column to the table currently being constructed.
+**
+** The parser calls this routine once for each column declaration
+** in a CREATE TABLE statement.  sqlite3StartTable() gets called
+** first to get things going.  Then this routine is called for each
+** column.
+*/
+SQLITE_PRIVATE void sqlite3AddColumn(Parse *pParse, Token sName, Token sType){
+  Table *p;
+  int i;
+  char *z;
+  char *zType;
+  Column *pCol;
+  sqlite3 *db = pParse->db;
+  u8 hName;
+  Column *aNew;
+  u8 eType = COLTYPE_CUSTOM;
+  u8 szEst = 1;
+  char affinity = SQLITE_AFF_BLOB;
+
+  if( (p = pParse->pNewTable)==0 ) return;
+  if( p->nCol+1>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many columns on %s", p->zName);
+    return;
+  }
+  if( !IN_RENAME_OBJECT ) sqlite3DequoteToken(&sName);
+
+  /* Because keywords GENERATE ALWAYS can be converted into identifiers
+  ** by the parser, we can sometimes end up with a typename that ends
+  ** with "generated always".  Check for this case and omit the surplus
+  ** text. */
+  if( sType.n>=16
+   && sqlite3_strnicmp(sType.z+(sType.n-6),"always",6)==0
+  ){
+    sType.n -= 6;
+    while( ALWAYS(sType.n>0) && sqlite3Isspace(sType.z[sType.n-1]) ) sType.n--;
+    if( sType.n>=9
+     && sqlite3_strnicmp(sType.z+(sType.n-9),"generated",9)==0
+    ){
+      sType.n -= 9;
+      while( sType.n>0 && sqlite3Isspace(sType.z[sType.n-1]) ) sType.n--;
+    }
+  }
+
+  /* Check for standard typenames.  For standard typenames we will
+  ** set the Column.eType field rather than storing the typename after
+  ** the column name, in order to save space. */
+  if( sType.n>=3 ){
+    sqlite3DequoteToken(&sType);
+    for(i=0; i<SQLITE_N_STDTYPE; i++){
+       if( sType.n==sqlite3StdTypeLen[i]
+        && sqlite3_strnicmp(sType.z, sqlite3StdType[i], sType.n)==0
+       ){
+         sType.n = 0;
+         eType = i+1;
+         affinity = sqlite3StdTypeAffinity[i];
+         if( affinity<=SQLITE_AFF_TEXT ) szEst = 5;
+         break;
+       }
+    }
+  }
+
+  z = sqlite3DbMallocRaw(db, (i64)sName.n + 1 + (i64)sType.n + (sType.n>0) );
+  if( z==0 ) return;
+  if( IN_RENAME_OBJECT ) sqlite3RenameTokenMap(pParse, (void*)z, &sName);
+  memcpy(z, sName.z, sName.n);
+  z[sName.n] = 0;
+  sqlite3Dequote(z);
+  hName = sqlite3StrIHash(z);
+  for(i=0; i<p->nCol; i++){
+    if( p->aCol[i].hName==hName && sqlite3StrICmp(z, p->aCol[i].zCnName)==0 ){
+      sqlite3ErrorMsg(pParse, "duplicate column name: %s", z);
+      sqlite3DbFree(db, z);
+      return;
+    }
+  }
+  aNew = sqlite3DbRealloc(db,p->aCol,((i64)p->nCol+1)*sizeof(p->aCol[0]));
+  if( aNew==0 ){
+    sqlite3DbFree(db, z);
+    return;
+  }
+  p->aCol = aNew;
+  pCol = &p->aCol[p->nCol];
+  memset(pCol, 0, sizeof(p->aCol[0]));
+  pCol->zCnName = z;
+  pCol->hName = hName;
+  sqlite3ColumnPropertiesFromName(p, pCol);
+
+  if( sType.n==0 ){
+    /* If there is no type specified, columns have the default affinity
+    ** 'BLOB' with a default size of 4 bytes. */
+    pCol->affinity = affinity;
+    pCol->eCType = eType;
+    pCol->szEst = szEst;
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( affinity==SQLITE_AFF_BLOB ){
+      if( 4>=sqlite3GlobalConfig.szSorterRef ){
+        pCol->colFlags |= COLFLAG_SORTERREF;
+      }
+    }
+#endif
+  }else{
+    zType = z + sqlite3Strlen30(z) + 1;
+    memcpy(zType, sType.z, sType.n);
+    zType[sType.n] = 0;
+    sqlite3Dequote(zType);
+    pCol->affinity = sqlite3AffinityType(zType, pCol);
+    pCol->colFlags |= COLFLAG_HASTYPE;
+  }
+  p->nCol++;
+  p->nNVCol++;
+  pParse->constraintName.n = 0;
+}
+
+/*
+** This routine is called by the parser while in the middle of
+** parsing a CREATE TABLE statement.  A "NOT NULL" constraint has
+** been seen on a column.  This routine sets the notNull flag on
+** the column currently under construction.
+*/
+SQLITE_PRIVATE void sqlite3AddNotNull(Parse *pParse, int onError){
+  Table *p;
+  Column *pCol;
+  p = pParse->pNewTable;
+  if( p==0 || NEVER(p->nCol<1) ) return;
+  pCol = &p->aCol[p->nCol-1];
+  pCol->notNull = (u8)onError;
+  p->tabFlags |= TF_HasNotNull;
+
+  /* Set the uniqNotNull flag on any UNIQUE or PK indexes already created
+  ** on this column.  */
+  if( pCol->colFlags & COLFLAG_UNIQUE ){
+    Index *pIdx;
+    for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
+      assert( pIdx->nKeyCol==1 && pIdx->onError!=OE_None );
+      if( pIdx->aiColumn[0]==p->nCol-1 ){
+        pIdx->uniqNotNull = 1;
+      }
+    }
+  }
+}
+
+/*
+** Scan the column type name zType (length nType) and return the
+** associated affinity type.
+**
+** This routine does a case-independent search of zType for the
+** substrings in the following table. If one of the substrings is
+** found, the corresponding affinity is returned. If zType contains
+** more than one of the substrings, entries toward the top of
+** the table take priority. For example, if zType is 'BLOBINT',
+** SQLITE_AFF_INTEGER is returned.
+**
+** Substring     | Affinity
+** --------------------------------
+** 'INT'         | SQLITE_AFF_INTEGER
+** 'CHAR'        | SQLITE_AFF_TEXT
+** 'CLOB'        | SQLITE_AFF_TEXT
+** 'TEXT'        | SQLITE_AFF_TEXT
+** 'BLOB'        | SQLITE_AFF_BLOB
+** 'REAL'        | SQLITE_AFF_REAL
+** 'FLOA'        | SQLITE_AFF_REAL
+** 'DOUB'        | SQLITE_AFF_REAL
+**
+** If none of the substrings in the above table are found,
+** SQLITE_AFF_NUMERIC is returned.
+*/
+SQLITE_PRIVATE char sqlite3AffinityType(const char *zIn, Column *pCol){
+  u32 h = 0;
+  char aff = SQLITE_AFF_NUMERIC;
+  const char *zChar = 0;
+
+  assert( zIn!=0 );
+  while( zIn[0] ){
+    u8 x = *(u8*)zIn;
+    h = (h<<8) + sqlite3UpperToLower[x];
+    zIn++;
+    if( h==(('c'<<24)+('h'<<16)+('a'<<8)+'r') ){             /* CHAR */
+      aff = SQLITE_AFF_TEXT;
+      zChar = zIn;
+    }else if( h==(('c'<<24)+('l'<<16)+('o'<<8)+'b') ){       /* CLOB */
+      aff = SQLITE_AFF_TEXT;
+    }else if( h==(('t'<<24)+('e'<<16)+('x'<<8)+'t') ){       /* TEXT */
+      aff = SQLITE_AFF_TEXT;
+    }else if( h==(('b'<<24)+('l'<<16)+('o'<<8)+'b')          /* BLOB */
+        && (aff==SQLITE_AFF_NUMERIC || aff==SQLITE_AFF_REAL) ){
+      aff = SQLITE_AFF_BLOB;
+      if( zIn[0]=='(' ) zChar = zIn;
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    }else if( h==(('r'<<24)+('e'<<16)+('a'<<8)+'l')          /* REAL */
+        && aff==SQLITE_AFF_NUMERIC ){
+      aff = SQLITE_AFF_REAL;
+    }else if( h==(('f'<<24)+('l'<<16)+('o'<<8)+'a')          /* FLOA */
+        && aff==SQLITE_AFF_NUMERIC ){
+      aff = SQLITE_AFF_REAL;
+    }else if( h==(('d'<<24)+('o'<<16)+('u'<<8)+'b')          /* DOUB */
+        && aff==SQLITE_AFF_NUMERIC ){
+      aff = SQLITE_AFF_REAL;
+#endif
+    }else if( (h&0x00FFFFFF)==(('i'<<16)+('n'<<8)+'t') ){    /* INT */
+      aff = SQLITE_AFF_INTEGER;
+      break;
+    }
+  }
+
+  /* If pCol is not NULL, store an estimate of the field size.  The
+  ** estimate is scaled so that the size of an integer is 1.  */
+  if( pCol ){
+    int v = 0;   /* default size is approx 4 bytes */
+    if( aff<SQLITE_AFF_NUMERIC ){
+      if( zChar ){
+        while( zChar[0] ){
+          if( sqlite3Isdigit(zChar[0]) ){
+            /* BLOB(k), VARCHAR(k), CHAR(k) -> r=(k/4+1) */
+            sqlite3GetInt32(zChar, &v);
+            break;
+          }
+          zChar++;
+        }
+      }else{
+        v = 16;   /* BLOB, TEXT, CLOB -> r=5  (approx 20 bytes)*/
+      }
+    }
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( v>=sqlite3GlobalConfig.szSorterRef ){
+      pCol->colFlags |= COLFLAG_SORTERREF;
+    }
+#endif
+    v = v/4 + 1;
+    if( v>255 ) v = 255;
+    pCol->szEst = v;
+  }
+  return aff;
+}
+
+/*
+** The expression is the default value for the most recently added column
+** of the table currently under construction.
+**
+** Default value expressions must be constant.  Raise an exception if this
+** is not the case.
+**
+** This routine is called by the parser while in the middle of
+** parsing a CREATE TABLE statement.
+*/
+SQLITE_PRIVATE void sqlite3AddDefaultValue(
+  Parse *pParse,           /* Parsing context */
+  Expr *pExpr,             /* The parsed expression of the default value */
+  const char *zStart,      /* Start of the default value text */
+  const char *zEnd         /* First character past end of default value text */
+){
+  Table *p;
+  Column *pCol;
+  sqlite3 *db = pParse->db;
+  p = pParse->pNewTable;
+  if( p!=0 ){
+    int isInit = db->init.busy && db->init.iDb!=1;
+    pCol = &(p->aCol[p->nCol-1]);
+    if( !sqlite3ExprIsConstantOrFunction(pExpr, isInit) ){
+      sqlite3ErrorMsg(pParse, "default value of column [%s] is not constant",
+          pCol->zCnName);
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    }else if( pCol->colFlags & COLFLAG_GENERATED ){
+      testcase( pCol->colFlags & COLFLAG_VIRTUAL );
+      testcase( pCol->colFlags & COLFLAG_STORED );
+      sqlite3ErrorMsg(pParse, "cannot use DEFAULT on a generated column");
+#endif
+    }else{
+      /* A copy of pExpr is used instead of the original, as pExpr contains
+      ** tokens that point to volatile memory.
+      */
+      Expr x, *pDfltExpr;
+      memset(&x, 0, sizeof(x));
+      x.op = TK_SPAN;
+      x.u.zToken = sqlite3DbSpanDup(db, zStart, zEnd);
+      x.pLeft = pExpr;
+      x.flags = EP_Skip;
+      pDfltExpr = sqlite3ExprDup(db, &x, EXPRDUP_REDUCE);
+      sqlite3DbFree(db, x.u.zToken);
+      sqlite3ColumnSetExpr(pParse, p, pCol, pDfltExpr);
+    }
+  }
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameExprUnmap(pParse, pExpr);
+  }
+  sqlite3ExprDelete(db, pExpr);
+}
+
+/*
+** Backwards Compatibility Hack:
+**
+** Historical versions of SQLite accepted strings as column names in
+** indexes and PRIMARY KEY constraints and in UNIQUE constraints.  Example:
+**
+**     CREATE TABLE xyz(a,b,c,d,e,PRIMARY KEY('a'),UNIQUE('b','c' COLLATE trim)
+**     CREATE INDEX abc ON xyz('c','d' DESC,'e' COLLATE nocase DESC);
+**
+** This is goofy.  But to preserve backwards compatibility we continue to
+** accept it.  This routine does the necessary conversion.  It converts
+** the expression given in its argument from a TK_STRING into a TK_ID
+** if the expression is just a TK_STRING with an optional COLLATE clause.
+** If the expression is anything other than TK_STRING, the expression is
+** unchanged.
+*/
+static void sqlite3StringToId(Expr *p){
+  if( p->op==TK_STRING ){
+    p->op = TK_ID;
+  }else if( p->op==TK_COLLATE && p->pLeft->op==TK_STRING ){
+    p->pLeft->op = TK_ID;
+  }
+}
+
+/*
+** Tag the given column as being part of the PRIMARY KEY
+*/
+static void makeColumnPartOfPrimaryKey(Parse *pParse, Column *pCol){
+  pCol->colFlags |= COLFLAG_PRIMKEY;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  if( pCol->colFlags & COLFLAG_GENERATED ){
+    testcase( pCol->colFlags & COLFLAG_VIRTUAL );
+    testcase( pCol->colFlags & COLFLAG_STORED );
+    sqlite3ErrorMsg(pParse,
+      "generated columns cannot be part of the PRIMARY KEY");
+  }
+#endif
+}
+
+/*
+** Designate the PRIMARY KEY for the table.  pList is a list of names
+** of columns that form the primary key.  If pList is NULL, then the
+** most recently added column of the table is the primary key.
+**
+** A table can have at most one primary key.  If the table already has
+** a primary key (and this is the second primary key) then create an
+** error.
+**
+** If the PRIMARY KEY is on a single column whose datatype is INTEGER,
+** then we will try to use that column as the rowid.  Set the Table.iPKey
+** field of the table under construction to be the index of the
+** INTEGER PRIMARY KEY column.  Table.iPKey is set to -1 if there is
+** no INTEGER PRIMARY KEY.
+**
+** If the key is not an INTEGER PRIMARY KEY, then create a unique
+** index for the key.  No index is created for INTEGER PRIMARY KEYs.
+*/
+SQLITE_PRIVATE void sqlite3AddPrimaryKey(
+  Parse *pParse,    /* Parsing context */
+  ExprList *pList,  /* List of field names to be indexed */
+  int onError,      /* What to do with a uniqueness conflict */
+  int autoInc,      /* True if the AUTOINCREMENT keyword is present */
+  int sortOrder     /* SQLITE_SO_ASC or SQLITE_SO_DESC */
+){
+  Table *pTab = pParse->pNewTable;
+  Column *pCol = 0;
+  int iCol = -1, i;
+  int nTerm;
+  if( pTab==0 ) goto primary_key_exit;
+  if( pTab->tabFlags & TF_HasPrimaryKey ){
+    sqlite3ErrorMsg(pParse,
+      "table \"%s\" has more than one primary key", pTab->zName);
+    goto primary_key_exit;
+  }
+  pTab->tabFlags |= TF_HasPrimaryKey;
+  if( pList==0 ){
+    iCol = pTab->nCol - 1;
+    pCol = &pTab->aCol[iCol];
+    makeColumnPartOfPrimaryKey(pParse, pCol);
+    nTerm = 1;
+  }else{
+    nTerm = pList->nExpr;
+    for(i=0; i<nTerm; i++){
+      Expr *pCExpr = sqlite3ExprSkipCollate(pList->a[i].pExpr);
+      assert( pCExpr!=0 );
+      sqlite3StringToId(pCExpr);
+      if( pCExpr->op==TK_ID ){
+        const char *zCName;
+        assert( !ExprHasProperty(pCExpr, EP_IntValue) );
+        zCName = pCExpr->u.zToken;
+        for(iCol=0; iCol<pTab->nCol; iCol++){
+          if( sqlite3StrICmp(zCName, pTab->aCol[iCol].zCnName)==0 ){
+            pCol = &pTab->aCol[iCol];
+            makeColumnPartOfPrimaryKey(pParse, pCol);
+            break;
+          }
+        }
+      }
+    }
+  }
+  if( nTerm==1
+   && pCol
+   && pCol->eCType==COLTYPE_INTEGER
+   && sortOrder!=SQLITE_SO_DESC
+  ){
+    if( IN_RENAME_OBJECT && pList ){
+      Expr *pCExpr = sqlite3ExprSkipCollate(pList->a[0].pExpr);
+      sqlite3RenameTokenRemap(pParse, &pTab->iPKey, pCExpr);
+    }
+    pTab->iPKey = iCol;
+    pTab->keyConf = (u8)onError;
+    assert( autoInc==0 || autoInc==1 );
+    pTab->tabFlags |= autoInc*TF_Autoincrement;
+    if( pList ) pParse->iPkSortOrder = pList->a[0].fg.sortFlags;
+    (void)sqlite3HasExplicitNulls(pParse, pList);
+  }else if( autoInc ){
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    sqlite3ErrorMsg(pParse, "AUTOINCREMENT is only allowed on an "
+       "INTEGER PRIMARY KEY");
+#endif
+  }else{
+    sqlite3CreateIndex(pParse, 0, 0, 0, pList, onError, 0,
+                           0, sortOrder, 0, SQLITE_IDXTYPE_PRIMARYKEY);
+    pList = 0;
+  }
+
+primary_key_exit:
+  sqlite3ExprListDelete(pParse->db, pList);
+  return;
+}
+
+/*
+** Add a new CHECK constraint to the table currently under construction.
+*/
+SQLITE_PRIVATE void sqlite3AddCheckConstraint(
+  Parse *pParse,      /* Parsing context */
+  Expr *pCheckExpr,   /* The check expression */
+  const char *zStart, /* Opening "(" */
+  const char *zEnd    /* Closing ")" */
+){
+#ifndef SQLITE_OMIT_CHECK
+  Table *pTab = pParse->pNewTable;
+  sqlite3 *db = pParse->db;
+  if( pTab && !IN_DECLARE_VTAB
+   && !sqlite3BtreeIsReadonly(db->aDb[db->init.iDb].pBt)
+  ){
+    pTab->pCheck = sqlite3ExprListAppend(pParse, pTab->pCheck, pCheckExpr);
+    if( pParse->constraintName.n ){
+      sqlite3ExprListSetName(pParse, pTab->pCheck, &pParse->constraintName, 1);
+    }else{
+      Token t;
+      for(zStart++; sqlite3Isspace(zStart[0]); zStart++){}
+      while( sqlite3Isspace(zEnd[-1]) ){ zEnd--; }
+      t.z = zStart;
+      t.n = (int)(zEnd - t.z);
+      sqlite3ExprListSetName(pParse, pTab->pCheck, &t, 1);
+    }
+  }else
+#endif
+  {
+    sqlite3ExprDelete(pParse->db, pCheckExpr);
+  }
+}
+
+/*
+** Set the collation function of the most recently parsed table column
+** to the CollSeq given.
+*/
+SQLITE_PRIVATE void sqlite3AddCollateType(Parse *pParse, Token *pToken){
+  Table *p;
+  int i;
+  char *zColl;              /* Dequoted name of collation sequence */
+  sqlite3 *db;
+
+  if( (p = pParse->pNewTable)==0 || IN_RENAME_OBJECT ) return;
+  i = p->nCol-1;
+  db = pParse->db;
+  zColl = sqlite3NameFromToken(db, pToken);
+  if( !zColl ) return;
+
+  if( sqlite3LocateCollSeq(pParse, zColl) ){
+    Index *pIdx;
+    sqlite3ColumnSetColl(db, &p->aCol[i], zColl);
+
+    /* If the column is declared as "<name> PRIMARY KEY COLLATE <type>",
+    ** then an index may have been created on this column before the
+    ** collation type was added. Correct this if it is the case.
+    */
+    for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
+      assert( pIdx->nKeyCol==1 );
+      if( pIdx->aiColumn[0]==i ){
+        pIdx->azColl[0] = sqlite3ColumnColl(&p->aCol[i]);
+      }
+    }
+  }
+  sqlite3DbFree(db, zColl);
+}
+
+/* Change the most recently parsed column to be a GENERATED ALWAYS AS
+** column.
+*/
+SQLITE_PRIVATE void sqlite3AddGenerated(Parse *pParse, Expr *pExpr, Token *pType){
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  u8 eType = COLFLAG_VIRTUAL;
+  Table *pTab = pParse->pNewTable;
+  Column *pCol;
+  if( pTab==0 ){
+    /* generated column in an CREATE TABLE IF NOT EXISTS that already exists */
+    goto generated_done;
+  }
+  pCol = &(pTab->aCol[pTab->nCol-1]);
+  if( IN_DECLARE_VTAB ){
+    sqlite3ErrorMsg(pParse, "virtual tables cannot use computed columns");
+    goto generated_done;
+  }
+  if( pCol->iDflt>0 ) goto generated_error;
+  if( pType ){
+    if( pType->n==7 && sqlite3StrNICmp("virtual",pType->z,7)==0 ){
+      /* no-op */
+    }else if( pType->n==6 && sqlite3StrNICmp("stored",pType->z,6)==0 ){
+      eType = COLFLAG_STORED;
+    }else{
+      goto generated_error;
+    }
+  }
+  if( eType==COLFLAG_VIRTUAL ) pTab->nNVCol--;
+  pCol->colFlags |= eType;
+  assert( TF_HasVirtual==COLFLAG_VIRTUAL );
+  assert( TF_HasStored==COLFLAG_STORED );
+  pTab->tabFlags |= eType;
+  if( pCol->colFlags & COLFLAG_PRIMKEY ){
+    makeColumnPartOfPrimaryKey(pParse, pCol); /* For the error message */
+  }
+  if( ALWAYS(pExpr) && pExpr->op==TK_ID ){
+    /* The value of a generated column needs to be a real expression, not
+    ** just a reference to another column, in order for covering index
+    ** optimizations to work correctly.  So if the value is not an expression,
+    ** turn it into one by adding a unary "+" operator. */
+    pExpr = sqlite3PExpr(pParse, TK_UPLUS, pExpr, 0);
+  }
+  if( pExpr && pExpr->op!=TK_RAISE ) pExpr->affExpr = pCol->affinity;
+  sqlite3ColumnSetExpr(pParse, pTab, pCol, pExpr);
+  pExpr = 0;
+  goto generated_done;
+
+generated_error:
+  sqlite3ErrorMsg(pParse, "error in generated column \"%s\"",
+                  pCol->zCnName);
+generated_done:
+  sqlite3ExprDelete(pParse->db, pExpr);
+#else
+  /* Throw and error for the GENERATED ALWAYS AS clause if the
+  ** SQLITE_OMIT_GENERATED_COLUMNS compile-time option is used. */
+  sqlite3ErrorMsg(pParse, "generated columns not supported");
+  sqlite3ExprDelete(pParse->db, pExpr);
+#endif
+}
+
+/*
+** Generate code that will increment the schema cookie.
+**
+** The schema cookie is used to determine when the schema for the
+** database changes.  After each schema change, the cookie value
+** changes.  When a process first reads the schema it records the
+** cookie.  Thereafter, whenever it goes to access the database,
+** it checks the cookie to make sure the schema has not changed
+** since it was last read.
+**
+** This plan is not completely bullet-proof.  It is possible for
+** the schema to change multiple times and for the cookie to be
+** set back to prior value.  But schema changes are infrequent
+** and the probability of hitting the same cookie value is only
+** 1 chance in 2^32.  So we're safe enough.
+**
+** IMPLEMENTATION-OF: R-34230-56049 SQLite automatically increments
+** the schema-version whenever the schema changes.
+*/
+SQLITE_PRIVATE void sqlite3ChangeCookie(Parse *pParse, int iDb){
+  sqlite3 *db = pParse->db;
+  Vdbe *v = pParse->pVdbe;
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_SCHEMA_VERSION,
+                   (int)(1+(unsigned)db->aDb[iDb].pSchema->schema_cookie));
+}
+
+/*
+** Measure the number of characters needed to output the given
+** identifier.  The number returned includes any quotes used
+** but does not include the null terminator.
+**
+** The estimate is conservative.  It might be larger that what is
+** really needed.
+*/
+static int identLength(const char *z){
+  int n;
+  for(n=0; *z; n++, z++){
+    if( *z=='"' ){ n++; }
+  }
+  return n + 2;
+}
+
+/*
+** The first parameter is a pointer to an output buffer. The second
+** parameter is a pointer to an integer that contains the offset at
+** which to write into the output buffer. This function copies the
+** nul-terminated string pointed to by the third parameter, zSignedIdent,
+** to the specified offset in the buffer and updates *pIdx to refer
+** to the first byte after the last byte written before returning.
+**
+** If the string zSignedIdent consists entirely of alphanumeric
+** characters, does not begin with a digit and is not an SQL keyword,
+** then it is copied to the output buffer exactly as it is. Otherwise,
+** it is quoted using double-quotes.
+*/
+static void identPut(char *z, int *pIdx, char *zSignedIdent){
+  unsigned char *zIdent = (unsigned char*)zSignedIdent;
+  int i, j, needQuote;
+  i = *pIdx;
+
+  for(j=0; zIdent[j]; j++){
+    if( !sqlite3Isalnum(zIdent[j]) && zIdent[j]!='_' ) break;
+  }
+  needQuote = sqlite3Isdigit(zIdent[0])
+            || sqlite3KeywordCode(zIdent, j)!=TK_ID
+            || zIdent[j]!=0
+            || j==0;
+
+  if( needQuote ) z[i++] = '"';
+  for(j=0; zIdent[j]; j++){
+    z[i++] = zIdent[j];
+    if( zIdent[j]=='"' ) z[i++] = '"';
+  }
+  if( needQuote ) z[i++] = '"';
+  z[i] = 0;
+  *pIdx = i;
+}
+
+/*
+** Generate a CREATE TABLE statement appropriate for the given
+** table.  Memory to hold the text of the statement is obtained
+** from sqliteMalloc() and must be freed by the calling function.
+*/
+static char *createTableStmt(sqlite3 *db, Table *p){
+  int i, k, n;
+  char *zStmt;
+  char *zSep, *zSep2, *zEnd;
+  Column *pCol;
+  n = 0;
+  for(pCol = p->aCol, i=0; i<p->nCol; i++, pCol++){
+    n += identLength(pCol->zCnName) + 5;
+  }
+  n += identLength(p->zName);
+  if( n<50 ){
+    zSep = "";
+    zSep2 = ",";
+    zEnd = ")";
+  }else{
+    zSep = "\n  ";
+    zSep2 = ",\n  ";
+    zEnd = "\n)";
+  }
+  n += 35 + 6*p->nCol;
+  zStmt = sqlite3DbMallocRaw(0, n);
+  if( zStmt==0 ){
+    sqlite3OomFault(db);
+    return 0;
+  }
+  sqlite3_snprintf(n, zStmt, "CREATE TABLE ");
+  k = sqlite3Strlen30(zStmt);
+  identPut(zStmt, &k, p->zName);
+  zStmt[k++] = '(';
+  for(pCol=p->aCol, i=0; i<p->nCol; i++, pCol++){
+    static const char * const azType[] = {
+        /* SQLITE_AFF_BLOB    */ "",
+        /* SQLITE_AFF_TEXT    */ " TEXT",
+        /* SQLITE_AFF_NUMERIC */ " NUM",
+        /* SQLITE_AFF_INTEGER */ " INT",
+        /* SQLITE_AFF_REAL    */ " REAL",
+        /* SQLITE_AFF_FLEXNUM */ " NUM",
+    };
+    int len;
+    const char *zType;
+
+    sqlite3_snprintf(n-k, &zStmt[k], zSep);
+    k += sqlite3Strlen30(&zStmt[k]);
+    zSep = zSep2;
+    identPut(zStmt, &k, pCol->zCnName);
+    assert( pCol->affinity-SQLITE_AFF_BLOB >= 0 );
+    assert( pCol->affinity-SQLITE_AFF_BLOB < ArraySize(azType) );
+    testcase( pCol->affinity==SQLITE_AFF_BLOB );
+    testcase( pCol->affinity==SQLITE_AFF_TEXT );
+    testcase( pCol->affinity==SQLITE_AFF_NUMERIC );
+    testcase( pCol->affinity==SQLITE_AFF_INTEGER );
+    testcase( pCol->affinity==SQLITE_AFF_REAL );
+    testcase( pCol->affinity==SQLITE_AFF_FLEXNUM );
+
+    zType = azType[pCol->affinity - SQLITE_AFF_BLOB];
+    len = sqlite3Strlen30(zType);
+    assert( pCol->affinity==SQLITE_AFF_BLOB
+            || pCol->affinity==SQLITE_AFF_FLEXNUM
+            || pCol->affinity==sqlite3AffinityType(zType, 0) );
+    memcpy(&zStmt[k], zType, len);
+    k += len;
+    assert( k<=n );
+  }
+  sqlite3_snprintf(n-k, &zStmt[k], "%s", zEnd);
+  return zStmt;
+}
+
+/*
+** Resize an Index object to hold N columns total.  Return SQLITE_OK
+** on success and SQLITE_NOMEM on an OOM error.
+*/
+static int resizeIndexObject(sqlite3 *db, Index *pIdx, int N){
+  char *zExtra;
+  int nByte;
+  if( pIdx->nColumn>=N ) return SQLITE_OK;
+  assert( pIdx->isResized==0 );
+  nByte = (sizeof(char*) + sizeof(LogEst) + sizeof(i16) + 1)*N;
+  zExtra = sqlite3DbMallocZero(db, nByte);
+  if( zExtra==0 ) return SQLITE_NOMEM_BKPT;
+  memcpy(zExtra, pIdx->azColl, sizeof(char*)*pIdx->nColumn);
+  pIdx->azColl = (const char**)zExtra;
+  zExtra += sizeof(char*)*N;
+  memcpy(zExtra, pIdx->aiRowLogEst, sizeof(LogEst)*(pIdx->nKeyCol+1));
+  pIdx->aiRowLogEst = (LogEst*)zExtra;
+  zExtra += sizeof(LogEst)*N;
+  memcpy(zExtra, pIdx->aiColumn, sizeof(i16)*pIdx->nColumn);
+  pIdx->aiColumn = (i16*)zExtra;
+  zExtra += sizeof(i16)*N;
+  memcpy(zExtra, pIdx->aSortOrder, pIdx->nColumn);
+  pIdx->aSortOrder = (u8*)zExtra;
+  pIdx->nColumn = N;
+  pIdx->isResized = 1;
+  return SQLITE_OK;
+}
+
+/*
+** Estimate the total row width for a table.
+*/
+static void estimateTableWidth(Table *pTab){
+  unsigned wTable = 0;
+  const Column *pTabCol;
+  int i;
+  for(i=pTab->nCol, pTabCol=pTab->aCol; i>0; i--, pTabCol++){
+    wTable += pTabCol->szEst;
+  }
+  if( pTab->iPKey<0 ) wTable++;
+  pTab->szTabRow = sqlite3LogEst(wTable*4);
+}
+
+/*
+** Estimate the average size of a row for an index.
+*/
+static void estimateIndexWidth(Index *pIdx){
+  unsigned wIndex = 0;
+  int i;
+  const Column *aCol = pIdx->pTable->aCol;
+  for(i=0; i<pIdx->nColumn; i++){
+    i16 x = pIdx->aiColumn[i];
+    assert( x<pIdx->pTable->nCol );
+    wIndex += x<0 ? 1 : aCol[x].szEst;
+  }
+  pIdx->szIdxRow = sqlite3LogEst(wIndex*4);
+}
+
+/* Return true if column number x is any of the first nCol entries of aiCol[].
+** This is used to determine if the column number x appears in any of the
+** first nCol entries of an index.
+*/
+static int hasColumn(const i16 *aiCol, int nCol, int x){
+  while( nCol-- > 0 ){
+    if( x==*(aiCol++) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Return true if any of the first nKey entries of index pIdx exactly
+** match the iCol-th entry of pPk.  pPk is always a WITHOUT ROWID
+** PRIMARY KEY index.  pIdx is an index on the same table.  pIdx may
+** or may not be the same index as pPk.
+**
+** The first nKey entries of pIdx are guaranteed to be ordinary columns,
+** not a rowid or expression.
+**
+** This routine differs from hasColumn() in that both the column and the
+** collating sequence must match for this routine, but for hasColumn() only
+** the column name must match.
+*/
+static int isDupColumn(Index *pIdx, int nKey, Index *pPk, int iCol){
+  int i, j;
+  assert( nKey<=pIdx->nColumn );
+  assert( iCol<MAX(pPk->nColumn,pPk->nKeyCol) );
+  assert( pPk->idxType==SQLITE_IDXTYPE_PRIMARYKEY );
+  assert( pPk->pTable->tabFlags & TF_WithoutRowid );
+  assert( pPk->pTable==pIdx->pTable );
+  testcase( pPk==pIdx );
+  j = pPk->aiColumn[iCol];
+  assert( j!=XN_ROWID && j!=XN_EXPR );
+  for(i=0; i<nKey; i++){
+    assert( pIdx->aiColumn[i]>=0 || j>=0 );
+    if( pIdx->aiColumn[i]==j
+     && sqlite3StrICmp(pIdx->azColl[i], pPk->azColl[iCol])==0
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/* Recompute the colNotIdxed field of the Index.
+**
+** colNotIdxed is a bitmask that has a 0 bit representing each indexed
+** columns that are within the first 63 columns of the table and a 1 for
+** all other bits (all columns that are not in the index).  The
+** high-order bit of colNotIdxed is always 1.  All unindexed columns
+** of the table have a 1.
+**
+** 2019-10-24:  For the purpose of this computation, virtual columns are
+** not considered to be covered by the index, even if they are in the
+** index, because we do not trust the logic in whereIndexExprTrans() to be
+** able to find all instances of a reference to the indexed table column
+** and convert them into references to the index.  Hence we always want
+** the actual table at hand in order to recompute the virtual column, if
+** necessary.
+**
+** The colNotIdxed mask is AND-ed with the SrcList.a[].colUsed mask
+** to determine if the index is covering index.
+*/
+static void recomputeColumnsNotIndexed(Index *pIdx){
+  Bitmask m = 0;
+  int j;
+  Table *pTab = pIdx->pTable;
+  for(j=pIdx->nColumn-1; j>=0; j--){
+    int x = pIdx->aiColumn[j];
+    if( x>=0 && (pTab->aCol[x].colFlags & COLFLAG_VIRTUAL)==0 ){
+      testcase( x==BMS-1 );
+      testcase( x==BMS-2 );
+      if( x<BMS-1 ) m |= MASKBIT(x);
+    }
+  }
+  pIdx->colNotIdxed = ~m;
+  assert( (pIdx->colNotIdxed>>63)==1 );  /* See note-20221022-a */
+}
+
+/*
+** This routine runs at the end of parsing a CREATE TABLE statement that
+** has a WITHOUT ROWID clause.  The job of this routine is to convert both
+** internal schema data structures and the generated VDBE code so that they
+** are appropriate for a WITHOUT ROWID table instead of a rowid table.
+** Changes include:
+**
+**     (1)  Set all columns of the PRIMARY KEY schema object to be NOT NULL.
+**     (2)  Convert P3 parameter of the OP_CreateBtree from BTREE_INTKEY
+**          into BTREE_BLOBKEY.
+**     (3)  Bypass the creation of the sqlite_schema table entry
+**          for the PRIMARY KEY as the primary key index is now
+**          identified by the sqlite_schema table entry of the table itself.
+**     (4)  Set the Index.tnum of the PRIMARY KEY Index object in the
+**          schema to the rootpage from the main table.
+**     (5)  Add all table columns to the PRIMARY KEY Index object
+**          so that the PRIMARY KEY is a covering index.  The surplus
+**          columns are part of KeyInfo.nAllField and are not used for
+**          sorting or lookup or uniqueness checks.
+**     (6)  Replace the rowid tail on all automatically generated UNIQUE
+**          indices with the PRIMARY KEY columns.
+**
+** For virtual tables, only (1) is performed.
+*/
+static void convertToWithoutRowidTable(Parse *pParse, Table *pTab){
+  Index *pIdx;
+  Index *pPk;
+  int nPk;
+  int nExtra;
+  int i, j;
+  sqlite3 *db = pParse->db;
+  Vdbe *v = pParse->pVdbe;
+
+  /* Mark every PRIMARY KEY column as NOT NULL (except for imposter tables)
+  */
+  if( !db->init.imposterTable ){
+    for(i=0; i<pTab->nCol; i++){
+      if( (pTab->aCol[i].colFlags & COLFLAG_PRIMKEY)!=0
+       && (pTab->aCol[i].notNull==OE_None)
+      ){
+        pTab->aCol[i].notNull = OE_Abort;
+      }
+    }
+    pTab->tabFlags |= TF_HasNotNull;
+  }
+
+  /* Convert the P3 operand of the OP_CreateBtree opcode from BTREE_INTKEY
+  ** into BTREE_BLOBKEY.
+  */
+  assert( !pParse->bReturning );
+  if( pParse->u1.addrCrTab ){
+    assert( v );
+    sqlite3VdbeChangeP3(v, pParse->u1.addrCrTab, BTREE_BLOBKEY);
+  }
+
+  /* Locate the PRIMARY KEY index.  Or, if this table was originally
+  ** an INTEGER PRIMARY KEY table, create a new PRIMARY KEY index.
+  */
+  if( pTab->iPKey>=0 ){
+    ExprList *pList;
+    Token ipkToken;
+    sqlite3TokenInit(&ipkToken, pTab->aCol[pTab->iPKey].zCnName);
+    pList = sqlite3ExprListAppend(pParse, 0,
+                  sqlite3ExprAlloc(db, TK_ID, &ipkToken, 0));
+    if( pList==0 ){
+      pTab->tabFlags &= ~TF_WithoutRowid;
+      return;
+    }
+    if( IN_RENAME_OBJECT ){
+      sqlite3RenameTokenRemap(pParse, pList->a[0].pExpr, &pTab->iPKey);
+    }
+    pList->a[0].fg.sortFlags = pParse->iPkSortOrder;
+    assert( pParse->pNewTable==pTab );
+    pTab->iPKey = -1;
+    sqlite3CreateIndex(pParse, 0, 0, 0, pList, pTab->keyConf, 0, 0, 0, 0,
+                       SQLITE_IDXTYPE_PRIMARYKEY);
+    if( pParse->nErr ){
+      pTab->tabFlags &= ~TF_WithoutRowid;
+      return;
+    }
+    assert( db->mallocFailed==0 );
+    pPk = sqlite3PrimaryKeyIndex(pTab);
+    assert( pPk->nKeyCol==1 );
+  }else{
+    pPk = sqlite3PrimaryKeyIndex(pTab);
+    assert( pPk!=0 );
+
+    /*
+    ** Remove all redundant columns from the PRIMARY KEY.  For example, change
+    ** "PRIMARY KEY(a,b,a,b,c,b,c,d)" into just "PRIMARY KEY(a,b,c,d)".  Later
+    ** code assumes the PRIMARY KEY contains no repeated columns.
+    */
+    for(i=j=1; i<pPk->nKeyCol; i++){
+      if( isDupColumn(pPk, j, pPk, i) ){
+        pPk->nColumn--;
+      }else{
+        testcase( hasColumn(pPk->aiColumn, j, pPk->aiColumn[i]) );
+        pPk->azColl[j] = pPk->azColl[i];
+        pPk->aSortOrder[j] = pPk->aSortOrder[i];
+        pPk->aiColumn[j++] = pPk->aiColumn[i];
+      }
+    }
+    pPk->nKeyCol = j;
+  }
+  assert( pPk!=0 );
+  pPk->isCovering = 1;
+  if( !db->init.imposterTable ) pPk->uniqNotNull = 1;
+  nPk = pPk->nColumn = pPk->nKeyCol;
+
+  /* Bypass the creation of the PRIMARY KEY btree and the sqlite_schema
+  ** table entry. This is only required if currently generating VDBE
+  ** code for a CREATE TABLE (not when parsing one as part of reading
+  ** a database schema).  */
+  if( v && pPk->tnum>0 ){
+    assert( db->init.busy==0 );
+    sqlite3VdbeChangeOpcode(v, (int)pPk->tnum, OP_Goto);
+  }
+
+  /* The root page of the PRIMARY KEY is the table root page */
+  pPk->tnum = pTab->tnum;
+
+  /* Update the in-memory representation of all UNIQUE indices by converting
+  ** the final rowid column into one or more columns of the PRIMARY KEY.
+  */
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    int n;
+    if( IsPrimaryKeyIndex(pIdx) ) continue;
+    for(i=n=0; i<nPk; i++){
+      if( !isDupColumn(pIdx, pIdx->nKeyCol, pPk, i) ){
+        testcase( hasColumn(pIdx->aiColumn, pIdx->nKeyCol, pPk->aiColumn[i]) );
+        n++;
+      }
+    }
+    if( n==0 ){
+      /* This index is a superset of the primary key */
+      pIdx->nColumn = pIdx->nKeyCol;
+      continue;
+    }
+    if( resizeIndexObject(db, pIdx, pIdx->nKeyCol+n) ) return;
+    for(i=0, j=pIdx->nKeyCol; i<nPk; i++){
+      if( !isDupColumn(pIdx, pIdx->nKeyCol, pPk, i) ){
+        testcase( hasColumn(pIdx->aiColumn, pIdx->nKeyCol, pPk->aiColumn[i]) );
+        pIdx->aiColumn[j] = pPk->aiColumn[i];
+        pIdx->azColl[j] = pPk->azColl[i];
+        if( pPk->aSortOrder[i] ){
+          /* See ticket https://www.sqlite.org/src/info/bba7b69f9849b5bf */
+          pIdx->bAscKeyBug = 1;
+        }
+        j++;
+      }
+    }
+    assert( pIdx->nColumn>=pIdx->nKeyCol+n );
+    assert( pIdx->nColumn>=j );
+  }
+
+  /* Add all table columns to the PRIMARY KEY index
+  */
+  nExtra = 0;
+  for(i=0; i<pTab->nCol; i++){
+    if( !hasColumn(pPk->aiColumn, nPk, i)
+     && (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0 ) nExtra++;
+  }
+  if( resizeIndexObject(db, pPk, nPk+nExtra) ) return;
+  for(i=0, j=nPk; i<pTab->nCol; i++){
+    if( !hasColumn(pPk->aiColumn, j, i)
+     && (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0
+    ){
+      assert( j<pPk->nColumn );
+      pPk->aiColumn[j] = i;
+      pPk->azColl[j] = sqlite3StrBINARY;
+      j++;
+    }
+  }
+  assert( pPk->nColumn==j );
+  assert( pTab->nNVCol<=j );
+  recomputeColumnsNotIndexed(pPk);
+}
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Return true if pTab is a virtual table and zName is a shadow table name
+** for that virtual table.
+*/
+SQLITE_PRIVATE int sqlite3IsShadowTableOf(sqlite3 *db, Table *pTab, const char *zName){
+  int nName;                    /* Length of zName */
+  Module *pMod;                 /* Module for the virtual table */
+
+  if( !IsVirtual(pTab) ) return 0;
+  nName = sqlite3Strlen30(pTab->zName);
+  if( sqlite3_strnicmp(zName, pTab->zName, nName)!=0 ) return 0;
+  if( zName[nName]!='_' ) return 0;
+  pMod = (Module*)sqlite3HashFind(&db->aModule, pTab->u.vtab.azArg[0]);
+  if( pMod==0 ) return 0;
+  if( pMod->pModule->iVersion<3 ) return 0;
+  if( pMod->pModule->xShadowName==0 ) return 0;
+  return pMod->pModule->xShadowName(zName+nName+1);
+}
+#endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Table pTab is a virtual table.  If it the virtual table implementation
+** exists and has an xShadowName method, then loop over all other ordinary
+** tables within the same schema looking for shadow tables of pTab, and mark
+** any shadow tables seen using the TF_Shadow flag.
+*/
+SQLITE_PRIVATE void sqlite3MarkAllShadowTablesOf(sqlite3 *db, Table *pTab){
+  int nName;                    /* Length of pTab->zName */
+  Module *pMod;                 /* Module for the virtual table */
+  HashElem *k;                  /* For looping through the symbol table */
+
+  assert( IsVirtual(pTab) );
+  pMod = (Module*)sqlite3HashFind(&db->aModule, pTab->u.vtab.azArg[0]);
+  if( pMod==0 ) return;
+  if( NEVER(pMod->pModule==0) ) return;
+  if( pMod->pModule->iVersion<3 ) return;
+  if( pMod->pModule->xShadowName==0 ) return;
+  assert( pTab->zName!=0 );
+  nName = sqlite3Strlen30(pTab->zName);
+  for(k=sqliteHashFirst(&pTab->pSchema->tblHash); k; k=sqliteHashNext(k)){
+    Table *pOther = sqliteHashData(k);
+    assert( pOther->zName!=0 );
+    if( !IsOrdinaryTable(pOther) ) continue;
+    if( pOther->tabFlags & TF_Shadow ) continue;
+    if( sqlite3StrNICmp(pOther->zName, pTab->zName, nName)==0
+     && pOther->zName[nName]=='_'
+     && pMod->pModule->xShadowName(pOther->zName+nName+1)
+    ){
+      pOther->tabFlags |= TF_Shadow;
+    }
+  }
+}
+#endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Return true if zName is a shadow table name in the current database
+** connection.
+**
+** zName is temporarily modified while this routine is running, but is
+** restored to its original value prior to this routine returning.
+*/
+SQLITE_PRIVATE int sqlite3ShadowTableName(sqlite3 *db, const char *zName){
+  char *zTail;                  /* Pointer to the last "_" in zName */
+  Table *pTab;                  /* Table that zName is a shadow of */
+  zTail = strrchr(zName, '_');
+  if( zTail==0 ) return 0;
+  *zTail = 0;
+  pTab = sqlite3FindTable(db, zName, 0);
+  *zTail = '_';
+  if( pTab==0 ) return 0;
+  if( !IsVirtual(pTab) ) return 0;
+  return sqlite3IsShadowTableOf(db, pTab, zName);
+}
+#endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */
+
+
+#ifdef SQLITE_DEBUG
+/*
+** Mark all nodes of an expression as EP_Immutable, indicating that
+** they should not be changed.  Expressions attached to a table or
+** index definition are tagged this way to help ensure that we do
+** not pass them into code generator routines by mistake.
+*/
+static int markImmutableExprStep(Walker *pWalker, Expr *pExpr){
+  (void)pWalker;
+  ExprSetVVAProperty(pExpr, EP_Immutable);
+  return WRC_Continue;
+}
+static void markExprListImmutable(ExprList *pList){
+  if( pList ){
+    Walker w;
+    memset(&w, 0, sizeof(w));
+    w.xExprCallback = markImmutableExprStep;
+    w.xSelectCallback = sqlite3SelectWalkNoop;
+    w.xSelectCallback2 = 0;
+    sqlite3WalkExprList(&w, pList);
+  }
+}
+#else
+#define markExprListImmutable(X)  /* no-op */
+#endif /* SQLITE_DEBUG */
+
+
+/*
+** This routine is called to report the final ")" that terminates
+** a CREATE TABLE statement.
+**
+** The table structure that other action routines have been building
+** is added to the internal hash tables, assuming no errors have
+** occurred.
+**
+** An entry for the table is made in the schema table on disk, unless
+** this is a temporary table or db->init.busy==1.  When db->init.busy==1
+** it means we are reading the sqlite_schema table because we just
+** connected to the database or because the sqlite_schema table has
+** recently changed, so the entry for this table already exists in
+** the sqlite_schema table.  We do not want to create it again.
+**
+** If the pSelect argument is not NULL, it means that this routine
+** was called to create a table generated from a
+** "CREATE TABLE ... AS SELECT ..." statement.  The column names of
+** the new table will match the result set of the SELECT.
+*/
+SQLITE_PRIVATE void sqlite3EndTable(
+  Parse *pParse,          /* Parse context */
+  Token *pCons,           /* The ',' token after the last column defn. */
+  Token *pEnd,            /* The ')' before options in the CREATE TABLE */
+  u32 tabOpts,            /* Extra table options. Usually 0. */
+  Select *pSelect         /* Select from a "CREATE ... AS SELECT" */
+){
+  Table *p;                 /* The new table */
+  sqlite3 *db = pParse->db; /* The database connection */
+  int iDb;                  /* Database in which the table lives */
+  Index *pIdx;              /* An implied index of the table */
+
+  if( pEnd==0 && pSelect==0 ){
+    return;
+  }
+  p = pParse->pNewTable;
+  if( p==0 ) return;
+
+  if( pSelect==0 && sqlite3ShadowTableName(db, p->zName) ){
+    p->tabFlags |= TF_Shadow;
+  }
+
+  /* If the db->init.busy is 1 it means we are reading the SQL off the
+  ** "sqlite_schema" or "sqlite_temp_schema" table on the disk.
+  ** So do not write to the disk again.  Extract the root page number
+  ** for the table from the db->init.newTnum field.  (The page number
+  ** should have been put there by the sqliteOpenCb routine.)
+  **
+  ** If the root page number is 1, that means this is the sqlite_schema
+  ** table itself.  So mark it read-only.
+  */
+  if( db->init.busy ){
+    if( pSelect || (!IsOrdinaryTable(p) && db->init.newTnum) ){
+      sqlite3ErrorMsg(pParse, "");
+      return;
+    }
+    p->tnum = db->init.newTnum;
+    if( p->tnum==1 ) p->tabFlags |= TF_Readonly;
+  }
+
+  /* Special processing for tables that include the STRICT keyword:
+  **
+  **   *  Do not allow custom column datatypes.  Every column must have
+  **      a datatype that is one of INT, INTEGER, REAL, TEXT, or BLOB.
+  **
+  **   *  If a PRIMARY KEY is defined, other than the INTEGER PRIMARY KEY,
+  **      then all columns of the PRIMARY KEY must have a NOT NULL
+  **      constraint.
+  */
+  if( tabOpts & TF_Strict ){
+    int ii;
+    p->tabFlags |= TF_Strict;
+    for(ii=0; ii<p->nCol; ii++){
+      Column *pCol = &p->aCol[ii];
+      if( pCol->eCType==COLTYPE_CUSTOM ){
+        if( pCol->colFlags & COLFLAG_HASTYPE ){
+          sqlite3ErrorMsg(pParse,
+            "unknown datatype for %s.%s: \"%s\"",
+            p->zName, pCol->zCnName, sqlite3ColumnType(pCol, "")
+          );
+        }else{
+          sqlite3ErrorMsg(pParse, "missing datatype for %s.%s",
+                          p->zName, pCol->zCnName);
+        }
+        return;
+      }else if( pCol->eCType==COLTYPE_ANY ){
+        pCol->affinity = SQLITE_AFF_BLOB;
+      }
+      if( (pCol->colFlags & COLFLAG_PRIMKEY)!=0
+       && p->iPKey!=ii
+       && pCol->notNull == OE_None
+      ){
+        pCol->notNull = OE_Abort;
+        p->tabFlags |= TF_HasNotNull;
+      }
+    }
+  }
+
+  assert( (p->tabFlags & TF_HasPrimaryKey)==0
+       || p->iPKey>=0 || sqlite3PrimaryKeyIndex(p)!=0 );
+  assert( (p->tabFlags & TF_HasPrimaryKey)!=0
+       || (p->iPKey<0 && sqlite3PrimaryKeyIndex(p)==0) );
+
+  /* Special processing for WITHOUT ROWID Tables */
+  if( tabOpts & TF_WithoutRowid ){
+    if( (p->tabFlags & TF_Autoincrement) ){
+      sqlite3ErrorMsg(pParse,
+          "AUTOINCREMENT not allowed on WITHOUT ROWID tables");
+      return;
+    }
+    if( (p->tabFlags & TF_HasPrimaryKey)==0 ){
+      sqlite3ErrorMsg(pParse, "PRIMARY KEY missing on table %s", p->zName);
+      return;
+    }
+    p->tabFlags |= TF_WithoutRowid | TF_NoVisibleRowid;
+    convertToWithoutRowidTable(pParse, p);
+  }
+  iDb = sqlite3SchemaToIndex(db, p->pSchema);
+
+#ifndef SQLITE_OMIT_CHECK
+  /* Resolve names in all CHECK constraint expressions.
+  */
+  if( p->pCheck ){
+    sqlite3ResolveSelfReference(pParse, p, NC_IsCheck, 0, p->pCheck);
+    if( pParse->nErr ){
+      /* If errors are seen, delete the CHECK constraints now, else they might
+      ** actually be used if PRAGMA writable_schema=ON is set. */
+      sqlite3ExprListDelete(db, p->pCheck);
+      p->pCheck = 0;
+    }else{
+      markExprListImmutable(p->pCheck);
+    }
+  }
+#endif /* !defined(SQLITE_OMIT_CHECK) */
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  if( p->tabFlags & TF_HasGenerated ){
+    int ii, nNG = 0;
+    testcase( p->tabFlags & TF_HasVirtual );
+    testcase( p->tabFlags & TF_HasStored );
+    for(ii=0; ii<p->nCol; ii++){
+      u32 colFlags = p->aCol[ii].colFlags;
+      if( (colFlags & COLFLAG_GENERATED)!=0 ){
+        Expr *pX = sqlite3ColumnExpr(p, &p->aCol[ii]);
+        testcase( colFlags & COLFLAG_VIRTUAL );
+        testcase( colFlags & COLFLAG_STORED );
+        if( sqlite3ResolveSelfReference(pParse, p, NC_GenCol, pX, 0) ){
+          /* If there are errors in resolving the expression, change the
+          ** expression to a NULL.  This prevents code generators that operate
+          ** on the expression from inserting extra parts into the expression
+          ** tree that have been allocated from lookaside memory, which is
+          ** illegal in a schema and will lead to errors or heap corruption
+          ** when the database connection closes. */
+          sqlite3ColumnSetExpr(pParse, p, &p->aCol[ii],
+               sqlite3ExprAlloc(db, TK_NULL, 0, 0));
+        }
+      }else{
+        nNG++;
+      }
+    }
+    if( nNG==0 ){
+      sqlite3ErrorMsg(pParse, "must have at least one non-generated column");
+      return;
+    }
+  }
+#endif
+
+  /* Estimate the average row size for the table and for all implied indices */
+  estimateTableWidth(p);
+  for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
+    estimateIndexWidth(pIdx);
+  }
+
+  /* If not initializing, then create a record for the new table
+  ** in the schema table of the database.
+  **
+  ** If this is a TEMPORARY table, write the entry into the auxiliary
+  ** file instead of into the main database file.
+  */
+  if( !db->init.busy ){
+    int n;
+    Vdbe *v;
+    char *zType;    /* "view" or "table" */
+    char *zType2;   /* "VIEW" or "TABLE" */
+    char *zStmt;    /* Text of the CREATE TABLE or CREATE VIEW statement */
+
+    v = sqlite3GetVdbe(pParse);
+    if( NEVER(v==0) ) return;
+
+    sqlite3VdbeAddOp1(v, OP_Close, 0);
+
+    /*
+    ** Initialize zType for the new view or table.
+    */
+    if( IsOrdinaryTable(p) ){
+      /* A regular table */
+      zType = "table";
+      zType2 = "TABLE";
+#ifndef SQLITE_OMIT_VIEW
+    }else{
+      /* A view */
+      zType = "view";
+      zType2 = "VIEW";
+#endif
+    }
+
+    /* If this is a CREATE TABLE xx AS SELECT ..., execute the SELECT
+    ** statement to populate the new table. The root-page number for the
+    ** new table is in register pParse->regRoot.
+    **
+    ** Once the SELECT has been coded by sqlite3Select(), it is in a
+    ** suitable state to query for the column names and types to be used
+    ** by the new table.
+    **
+    ** A shared-cache write-lock is not required to write to the new table,
+    ** as a schema-lock must have already been obtained to create it. Since
+    ** a schema-lock excludes all other database users, the write-lock would
+    ** be redundant.
+    */
+    if( pSelect ){
+      SelectDest dest;    /* Where the SELECT should store results */
+      int regYield;       /* Register holding co-routine entry-point */
+      int addrTop;        /* Top of the co-routine */
+      int regRec;         /* A record to be insert into the new table */
+      int regRowid;       /* Rowid of the next row to insert */
+      int addrInsLoop;    /* Top of the loop for inserting rows */
+      Table *pSelTab;     /* A table that describes the SELECT results */
+      int iCsr;           /* Write cursor on the new table */
+
+      if( IN_SPECIAL_PARSE ){
+        pParse->rc = SQLITE_ERROR;
+        pParse->nErr++;
+        return;
+      }
+      iCsr = pParse->nTab++;
+      regYield = ++pParse->nMem;
+      regRec = ++pParse->nMem;
+      regRowid = ++pParse->nMem;
+      sqlite3MayAbort(pParse);
+      sqlite3VdbeAddOp3(v, OP_OpenWrite, iCsr, pParse->regRoot, iDb);
+      sqlite3VdbeChangeP5(v, OPFLAG_P2ISREG);
+      addrTop = sqlite3VdbeCurrentAddr(v) + 1;
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
+      if( pParse->nErr ) return;
+      pSelTab = sqlite3ResultSetOfSelect(pParse, pSelect, SQLITE_AFF_BLOB);
+      if( pSelTab==0 ) return;
+      assert( p->aCol==0 );
+      p->nCol = p->nNVCol = pSelTab->nCol;
+      p->aCol = pSelTab->aCol;
+      pSelTab->nCol = 0;
+      pSelTab->aCol = 0;
+      sqlite3DeleteTable(db, pSelTab);
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
+      sqlite3Select(pParse, pSelect, &dest);
+      if( pParse->nErr ) return;
+      sqlite3VdbeEndCoroutine(v, regYield);
+      sqlite3VdbeJumpHere(v, addrTop - 1);
+      addrInsLoop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, dest.iSdst, dest.nSdst, regRec);
+      sqlite3TableAffinity(v, p, 0);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, iCsr, regRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, iCsr, regRec, regRowid);
+      sqlite3VdbeGoto(v, addrInsLoop);
+      sqlite3VdbeJumpHere(v, addrInsLoop);
+      sqlite3VdbeAddOp1(v, OP_Close, iCsr);
+    }
+
+    /* Compute the complete text of the CREATE statement */
+    if( pSelect ){
+      zStmt = createTableStmt(db, p);
+    }else{
+      Token *pEnd2 = tabOpts ? &pParse->sLastToken : pEnd;
+      n = (int)(pEnd2->z - pParse->sNameToken.z);
+      if( pEnd2->z[0]!=';' ) n += pEnd2->n;
+      zStmt = sqlite3MPrintf(db,
+          "CREATE %s %.*s", zType2, n, pParse->sNameToken.z
+      );
+    }
+
+    /* A slot for the record has already been allocated in the
+    ** schema table.  We just need to update that slot with all
+    ** the information we've collected.
+    */
+    sqlite3NestedParse(pParse,
+      "UPDATE %Q." LEGACY_SCHEMA_TABLE
+      " SET type='%s', name=%Q, tbl_name=%Q, rootpage=#%d, sql=%Q"
+      " WHERE rowid=#%d",
+      db->aDb[iDb].zDbSName,
+      zType,
+      p->zName,
+      p->zName,
+      pParse->regRoot,
+      zStmt,
+      pParse->regRowid
+    );
+    sqlite3DbFree(db, zStmt);
+    sqlite3ChangeCookie(pParse, iDb);
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    /* Check to see if we need to create an sqlite_sequence table for
+    ** keeping track of autoincrement keys.
+    */
+    if( (p->tabFlags & TF_Autoincrement)!=0 && !IN_SPECIAL_PARSE ){
+      Db *pDb = &db->aDb[iDb];
+      assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+      if( pDb->pSchema->pSeqTab==0 ){
+        sqlite3NestedParse(pParse,
+          "CREATE TABLE %Q.sqlite_sequence(name,seq)",
+          pDb->zDbSName
+        );
+      }
+    }
+#endif
+
+    /* Reparse everything to update our internal data structures */
+    sqlite3VdbeAddParseSchemaOp(v, iDb,
+           sqlite3MPrintf(db, "tbl_name='%q' AND type!='trigger'", p->zName),0);
+
+    /* Test for cycles in generated columns and illegal expressions
+    ** in CHECK constraints and in DEFAULT clauses. */
+    if( p->tabFlags & TF_HasGenerated ){
+      sqlite3VdbeAddOp4(v, OP_SqlExec, 0x0001, 0, 0,
+             sqlite3MPrintf(db, "SELECT*FROM\"%w\".\"%w\"",
+                   db->aDb[iDb].zDbSName, p->zName), P4_DYNAMIC);
+    }
+  }
+
+  /* Add the table to the in-memory representation of the database.
+  */
+  if( db->init.busy ){
+    Table *pOld;
+    Schema *pSchema = p->pSchema;
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    assert( HasRowid(p) || p->iPKey<0 );
+    pOld = sqlite3HashInsert(&pSchema->tblHash, p->zName, p);
+    if( pOld ){
+      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
+      sqlite3OomFault(db);
+      return;
+    }
+    pParse->pNewTable = 0;
+    db->mDbFlags |= DBFLAG_SchemaChange;
+
+    /* If this is the magic sqlite_sequence table used by autoincrement,
+    ** then record a pointer to this table in the main database structure
+    ** so that INSERT can find the table easily.  */
+    assert( !pParse->nested );
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+    if( strcmp(p->zName, "sqlite_sequence")==0 ){
+      assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+      p->pSchema->pSeqTab = p;
+    }
+#endif
+  }
+
+#ifndef SQLITE_OMIT_ALTERTABLE
+  if( !pSelect && IsOrdinaryTable(p) ){
+    assert( pCons && pEnd );
+    if( pCons->z==0 ){
+      pCons = pEnd;
+    }
+    p->u.tab.addColOffset = 13 + (int)(pCons->z - pParse->sNameToken.z);
+  }
+#endif
+}
+
+#ifndef SQLITE_OMIT_VIEW
+/*
+** The parser calls this routine in order to create a new VIEW
+*/
+SQLITE_PRIVATE void sqlite3CreateView(
+  Parse *pParse,     /* The parsing context */
+  Token *pBegin,     /* The CREATE token that begins the statement */
+  Token *pName1,     /* The token that holds the name of the view */
+  Token *pName2,     /* The token that holds the name of the view */
+  ExprList *pCNames, /* Optional list of view column names */
+  Select *pSelect,   /* A SELECT statement that will become the new view */
+  int isTemp,        /* TRUE for a TEMPORARY view */
+  int noErr          /* Suppress error messages if VIEW already exists */
+){
+  Table *p;
+  int n;
+  const char *z;
+  Token sEnd;
+  DbFixer sFix;
+  Token *pName = 0;
+  int iDb;
+  sqlite3 *db = pParse->db;
+
+  if( pParse->nVar>0 ){
+    sqlite3ErrorMsg(pParse, "parameters are not allowed in views");
+    goto create_view_fail;
+  }
+  sqlite3StartTable(pParse, pName1, pName2, isTemp, 1, 0, noErr);
+  p = pParse->pNewTable;
+  if( p==0 || pParse->nErr ) goto create_view_fail;
+
+  /* Legacy versions of SQLite allowed the use of the magic "rowid" column
+  ** on a view, even though views do not have rowids.  The following flag
+  ** setting fixes this problem.  But the fix can be disabled by compiling
+  ** with -DSQLITE_ALLOW_ROWID_IN_VIEW in case there are legacy apps that
+  ** depend upon the old buggy behavior.  The ability can also be toggled
+  ** using sqlite3_config(SQLITE_CONFIG_ROWID_IN_VIEW,...) */
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  p->tabFlags |= sqlite3Config.mNoVisibleRowid; /* Optional. Allow by default */
+#else
+  p->tabFlags |= TF_NoVisibleRowid;             /* Never allow rowid in view */
+#endif
+
+  sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+  iDb = sqlite3SchemaToIndex(db, p->pSchema);
+  sqlite3FixInit(&sFix, pParse, iDb, "view", pName);
+  if( sqlite3FixSelect(&sFix, pSelect) ) goto create_view_fail;
+
+  /* Make a copy of the entire SELECT statement that defines the view.
+  ** This will force all the Expr.token.z values to be dynamically
+  ** allocated rather than point to the input string - which means that
+  ** they will persist after the current sqlite3_exec() call returns.
+  */
+  pSelect->selFlags |= SF_View;
+  if( IN_RENAME_OBJECT ){
+    p->u.view.pSelect = pSelect;
+    pSelect = 0;
+  }else{
+    p->u.view.pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
+  }
+  p->pCheck = sqlite3ExprListDup(db, pCNames, EXPRDUP_REDUCE);
+  p->eTabType = TABTYP_VIEW;
+  if( db->mallocFailed ) goto create_view_fail;
+
+  /* Locate the end of the CREATE VIEW statement.  Make sEnd point to
+  ** the end.
+  */
+  sEnd = pParse->sLastToken;
+  assert( sEnd.z[0]!=0 || sEnd.n==0 );
+  if( sEnd.z[0]!=';' ){
+    sEnd.z += sEnd.n;
+  }
+  sEnd.n = 0;
+  n = (int)(sEnd.z - pBegin->z);
+  assert( n>0 );
+  z = pBegin->z;
+  while( sqlite3Isspace(z[n-1]) ){ n--; }
+  sEnd.z = &z[n-1];
+  sEnd.n = 1;
+
+  /* Use sqlite3EndTable() to add the view to the schema table */
+  sqlite3EndTable(pParse, 0, &sEnd, 0, 0);
+
+create_view_fail:
+  sqlite3SelectDelete(db, pSelect);
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameExprlistUnmap(pParse, pCNames);
+  }
+  sqlite3ExprListDelete(db, pCNames);
+  return;
+}
+#endif /* SQLITE_OMIT_VIEW */
+
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+/*
+** The Table structure pTable is really a VIEW.  Fill in the names of
+** the columns of the view in the pTable structure.  Return non-zero if
+** there are errors.  If an error is seen an error message is left
+** in pParse->zErrMsg.
+*/
+static SQLITE_NOINLINE int viewGetColumnNames(Parse *pParse, Table *pTable){
+  Table *pSelTab;   /* A fake table from which we get the result set */
+  Select *pSel;     /* Copy of the SELECT that implements the view */
+  int nErr = 0;     /* Number of errors encountered */
+  sqlite3 *db = pParse->db;  /* Database connection for malloc errors */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  int rc;
+#endif
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  sqlite3_xauth xAuth;       /* Saved xAuth pointer */
+#endif
+
+  assert( pTable );
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTable) ){
+    db->nSchemaLock++;
+    rc = sqlite3VtabCallConnect(pParse, pTable);
+    db->nSchemaLock--;
+    return rc;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_VIEW
+  /* A positive nCol means the columns names for this view are
+  ** already known.  This routine is not called unless either the
+  ** table is virtual or nCol is zero.
+  */
+  assert( pTable->nCol<=0 );
+
+  /* A negative nCol is a special marker meaning that we are currently
+  ** trying to compute the column names.  If we enter this routine with
+  ** a negative nCol, it means two or more views form a loop, like this:
+  **
+  **     CREATE VIEW one AS SELECT * FROM two;
+  **     CREATE VIEW two AS SELECT * FROM one;
+  **
+  ** Actually, the error above is now caught prior to reaching this point.
+  ** But the following test is still important as it does come up
+  ** in the following:
+  **
+  **     CREATE TABLE main.ex1(a);
+  **     CREATE TEMP VIEW ex1 AS SELECT a FROM ex1;
+  **     SELECT * FROM temp.ex1;
+  */
+  if( pTable->nCol<0 ){
+    sqlite3ErrorMsg(pParse, "view %s is circularly defined", pTable->zName);
+    return 1;
+  }
+  assert( pTable->nCol>=0 );
+
+  /* If we get this far, it means we need to compute the table names.
+  ** Note that the call to sqlite3ResultSetOfSelect() will expand any
+  ** "*" elements in the results set of the view and will assign cursors
+  ** to the elements of the FROM clause.  But we do not want these changes
+  ** to be permanent.  So the computation is done on a copy of the SELECT
+  ** statement that defines the view.
+  */
+  assert( IsView(pTable) );
+  pSel = sqlite3SelectDup(db, pTable->u.view.pSelect, 0);
+  if( pSel ){
+    u8 eParseMode = pParse->eParseMode;
+    int nTab = pParse->nTab;
+    int nSelect = pParse->nSelect;
+    pParse->eParseMode = PARSE_MODE_NORMAL;
+    sqlite3SrcListAssignCursors(pParse, pSel->pSrc);
+    pTable->nCol = -1;
+    DisableLookaside;
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    xAuth = db->xAuth;
+    db->xAuth = 0;
+    pSelTab = sqlite3ResultSetOfSelect(pParse, pSel, SQLITE_AFF_NONE);
+    db->xAuth = xAuth;
+#else
+    pSelTab = sqlite3ResultSetOfSelect(pParse, pSel, SQLITE_AFF_NONE);
+#endif
+    pParse->nTab = nTab;
+    pParse->nSelect = nSelect;
+    if( pSelTab==0 ){
+      pTable->nCol = 0;
+      nErr++;
+    }else if( pTable->pCheck ){
+      /* CREATE VIEW name(arglist) AS ...
+      ** The names of the columns in the table are taken from
+      ** arglist which is stored in pTable->pCheck.  The pCheck field
+      ** normally holds CHECK constraints on an ordinary table, but for
+      ** a VIEW it holds the list of column names.
+      */
+      sqlite3ColumnsFromExprList(pParse, pTable->pCheck,
+                                 &pTable->nCol, &pTable->aCol);
+      if( pParse->nErr==0
+       && pTable->nCol==pSel->pEList->nExpr
+      ){
+        assert( db->mallocFailed==0 );
+        sqlite3SubqueryColumnTypes(pParse, pTable, pSel, SQLITE_AFF_NONE);
+      }
+    }else{
+      /* CREATE VIEW name AS...  without an argument list.  Construct
+      ** the column names from the SELECT statement that defines the view.
+      */
+      assert( pTable->aCol==0 );
+      pTable->nCol = pSelTab->nCol;
+      pTable->aCol = pSelTab->aCol;
+      pTable->tabFlags |= (pSelTab->tabFlags & COLFLAG_NOINSERT);
+      pSelTab->nCol = 0;
+      pSelTab->aCol = 0;
+      assert( sqlite3SchemaMutexHeld(db, 0, pTable->pSchema) );
+    }
+    pTable->nNVCol = pTable->nCol;
+    sqlite3DeleteTable(db, pSelTab);
+    sqlite3SelectDelete(db, pSel);
+    EnableLookaside;
+    pParse->eParseMode = eParseMode;
+  } else {
+    nErr++;
+  }
+  pTable->pSchema->schemaFlags |= DB_UnresetViews;
+  if( db->mallocFailed ){
+    sqlite3DeleteColumnNames(db, pTable);
+  }
+#endif /* SQLITE_OMIT_VIEW */
+  return nErr + pParse->nErr;
+}
+SQLITE_PRIVATE int sqlite3ViewGetColumnNames(Parse *pParse, Table *pTable){
+  assert( pTable!=0 );
+  if( !IsVirtual(pTable) && pTable->nCol>0 ) return 0;
+  return viewGetColumnNames(pParse, pTable);
+}
+#endif /* !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE) */
+
+#ifndef SQLITE_OMIT_VIEW
+/*
+** Clear the column names from every VIEW in database idx.
+*/
+static void sqliteViewResetAll(sqlite3 *db, int idx){
+  HashElem *i;
+  assert( sqlite3SchemaMutexHeld(db, idx, 0) );
+  if( !DbHasProperty(db, idx, DB_UnresetViews) ) return;
+  for(i=sqliteHashFirst(&db->aDb[idx].pSchema->tblHash); i;i=sqliteHashNext(i)){
+    Table *pTab = sqliteHashData(i);
+    if( IsView(pTab) ){
+      sqlite3DeleteColumnNames(db, pTab);
+    }
+  }
+  DbClearProperty(db, idx, DB_UnresetViews);
+}
+#else
+# define sqliteViewResetAll(A,B)
+#endif /* SQLITE_OMIT_VIEW */
+
+/*
+** This function is called by the VDBE to adjust the internal schema
+** used by SQLite when the btree layer moves a table root page. The
+** root-page of a table or index in database iDb has changed from iFrom
+** to iTo.
+**
+** Ticket #1728:  The symbol table might still contain information
+** on tables and/or indices that are the process of being deleted.
+** If you are unlucky, one of those deleted indices or tables might
+** have the same rootpage number as the real table or index that is
+** being moved.  So we cannot stop searching after the first match
+** because the first match might be for one of the deleted indices
+** or tables and not the table/index that is actually being moved.
+** We must continue looping until all tables and indices with
+** rootpage==iFrom have been converted to have a rootpage of iTo
+** in order to be certain that we got the right one.
+*/
+#ifndef SQLITE_OMIT_AUTOVACUUM
+SQLITE_PRIVATE void sqlite3RootPageMoved(sqlite3 *db, int iDb, Pgno iFrom, Pgno iTo){
+  HashElem *pElem;
+  Hash *pHash;
+  Db *pDb;
+
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  pDb = &db->aDb[iDb];
+  pHash = &pDb->pSchema->tblHash;
+  for(pElem=sqliteHashFirst(pHash); pElem; pElem=sqliteHashNext(pElem)){
+    Table *pTab = sqliteHashData(pElem);
+    if( pTab->tnum==iFrom ){
+      pTab->tnum = iTo;
+    }
+  }
+  pHash = &pDb->pSchema->idxHash;
+  for(pElem=sqliteHashFirst(pHash); pElem; pElem=sqliteHashNext(pElem)){
+    Index *pIdx = sqliteHashData(pElem);
+    if( pIdx->tnum==iFrom ){
+      pIdx->tnum = iTo;
+    }
+  }
+}
+#endif
+
+/*
+** Write code to erase the table with root-page iTable from database iDb.
+** Also write code to modify the sqlite_schema table and internal schema
+** if a root-page of another table is moved by the btree-layer whilst
+** erasing iTable (this can happen with an auto-vacuum database).
+*/
+static void destroyRootPage(Parse *pParse, int iTable, int iDb){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int r1 = sqlite3GetTempReg(pParse);
+  if( iTable<2 ) sqlite3ErrorMsg(pParse, "corrupt schema");
+  sqlite3VdbeAddOp3(v, OP_Destroy, iTable, r1, iDb);
+  sqlite3MayAbort(pParse);
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  /* OP_Destroy stores an in integer r1. If this integer
+  ** is non-zero, then it is the root page number of a table moved to
+  ** location iTable. The following code modifies the sqlite_schema table to
+  ** reflect this.
+  **
+  ** The "#NNN" in the SQL is a special constant that means whatever value
+  ** is in register NNN.  See grammar rules associated with the TK_REGISTER
+  ** token for additional information.
+  */
+  sqlite3NestedParse(pParse,
+     "UPDATE %Q." LEGACY_SCHEMA_TABLE
+     " SET rootpage=%d WHERE #%d AND rootpage=#%d",
+     pParse->db->aDb[iDb].zDbSName, iTable, r1, r1);
+#endif
+  sqlite3ReleaseTempReg(pParse, r1);
+}
+
+/*
+** Write VDBE code to erase table pTab and all associated indices on disk.
+** Code to update the sqlite_schema tables and internal schema definitions
+** in case a root-page belonging to another table is moved by the btree layer
+** is also added (this can happen with an auto-vacuum database).
+*/
+static void destroyTable(Parse *pParse, Table *pTab){
+  /* If the database may be auto-vacuum capable (if SQLITE_OMIT_AUTOVACUUM
+  ** is not defined), then it is important to call OP_Destroy on the
+  ** table and index root-pages in order, starting with the numerically
+  ** largest root-page number. This guarantees that none of the root-pages
+  ** to be destroyed is relocated by an earlier OP_Destroy. i.e. if the
+  ** following were coded:
+  **
+  ** OP_Destroy 4 0
+  ** ...
+  ** OP_Destroy 5 0
+  **
+  ** and root page 5 happened to be the largest root-page number in the
+  ** database, then root page 5 would be moved to page 4 by the
+  ** "OP_Destroy 4 0" opcode. The subsequent "OP_Destroy 5 0" would hit
+  ** a free-list page.
+  */
+  Pgno iTab = pTab->tnum;
+  Pgno iDestroyed = 0;
+
+  while( 1 ){
+    Index *pIdx;
+    Pgno iLargest = 0;
+
+    if( iDestroyed==0 || iTab<iDestroyed ){
+      iLargest = iTab;
+    }
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      Pgno iIdx = pIdx->tnum;
+      assert( pIdx->pSchema==pTab->pSchema );
+      if( (iDestroyed==0 || (iIdx<iDestroyed)) && iIdx>iLargest ){
+        iLargest = iIdx;
+      }
+    }
+    if( iLargest==0 ){
+      return;
+    }else{
+      int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+      assert( iDb>=0 && iDb<pParse->db->nDb );
+      destroyRootPage(pParse, iLargest, iDb);
+      iDestroyed = iLargest;
+    }
+  }
+}
+
+/*
+** Remove entries from the sqlite_statN tables (for N in (1,2,3))
+** after a DROP INDEX or DROP TABLE command.
+*/
+static void sqlite3ClearStatTables(
+  Parse *pParse,         /* The parsing context */
+  int iDb,               /* The database number */
+  const char *zType,     /* "idx" or "tbl" */
+  const char *zName      /* Name of index or table */
+){
+  int i;
+  const char *zDbName = pParse->db->aDb[iDb].zDbSName;
+  for(i=1; i<=4; i++){
+    char zTab[24];
+    sqlite3_snprintf(sizeof(zTab),zTab,"sqlite_stat%d",i);
+    if( sqlite3FindTable(pParse->db, zTab, zDbName) ){
+      sqlite3NestedParse(pParse,
+        "DELETE FROM %Q.%s WHERE %s=%Q",
+        zDbName, zTab, zType, zName
+      );
+    }
+  }
+}
+
+/*
+** Generate code to drop a table.
+*/
+SQLITE_PRIVATE void sqlite3CodeDropTable(Parse *pParse, Table *pTab, int iDb, int isView){
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  Trigger *pTrigger;
+  Db *pDb = &db->aDb[iDb];
+
+  v = sqlite3GetVdbe(pParse);
+  assert( v!=0 );
+  sqlite3BeginWriteOperation(pParse, 1, iDb);
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    sqlite3VdbeAddOp0(v, OP_VBegin);
+  }
+#endif
+
+  /* Drop all triggers associated with the table being dropped. Code
+  ** is generated to remove entries from sqlite_schema and/or
+  ** sqlite_temp_schema if required.
+  */
+  pTrigger = sqlite3TriggerList(pParse, pTab);
+  while( pTrigger ){
+    assert( pTrigger->pSchema==pTab->pSchema ||
+        pTrigger->pSchema==db->aDb[1].pSchema );
+    sqlite3DropTriggerPtr(pParse, pTrigger);
+    pTrigger = pTrigger->pNext;
+  }
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+  /* Remove any entries of the sqlite_sequence table associated with
+  ** the table being dropped. This is done before the table is dropped
+  ** at the btree level, in case the sqlite_sequence table needs to
+  ** move as a result of the drop (can happen in auto-vacuum mode).
+  */
+  if( pTab->tabFlags & TF_Autoincrement ){
+    sqlite3NestedParse(pParse,
+      "DELETE FROM %Q.sqlite_sequence WHERE name=%Q",
+      pDb->zDbSName, pTab->zName
+    );
+  }
+#endif
+
+  /* Drop all entries in the schema table that refer to the
+  ** table. The program name loops through the schema table and deletes
+  ** every row that refers to a table of the same name as the one being
+  ** dropped. Triggers are handled separately because a trigger can be
+  ** created in the temp database that refers to a table in another
+  ** database.
+  */
+  sqlite3NestedParse(pParse,
+      "DELETE FROM %Q." LEGACY_SCHEMA_TABLE
+      " WHERE tbl_name=%Q and type!='trigger'",
+      pDb->zDbSName, pTab->zName);
+  if( !isView && !IsVirtual(pTab) ){
+    destroyTable(pParse, pTab);
+  }
+
+  /* Remove the table entry from SQLite's internal schema and modify
+  ** the schema cookie.
+  */
+  if( IsVirtual(pTab) ){
+    sqlite3VdbeAddOp4(v, OP_VDestroy, iDb, 0, 0, pTab->zName, 0);
+    sqlite3MayAbort(pParse);
+  }
+  sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);
+  sqlite3ChangeCookie(pParse, iDb);
+  sqliteViewResetAll(db, iDb);
+}
+
+/*
+** Return TRUE if shadow tables should be read-only in the current
+** context.
+*/
+SQLITE_PRIVATE int sqlite3ReadOnlyShadowTables(sqlite3 *db){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( (db->flags & SQLITE_Defensive)!=0
+   && db->pVtabCtx==0
+   && db->nVdbeExec==0
+   && !sqlite3VtabInSync(db)
+  ){
+    return 1;
+  }
+#endif
+  return 0;
+}
+
+/*
+** Return true if it is not allowed to drop the given table
+*/
+static int tableMayNotBeDropped(sqlite3 *db, Table *pTab){
+  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
+    if( sqlite3StrNICmp(pTab->zName+7, "stat", 4)==0 ) return 0;
+    if( sqlite3StrNICmp(pTab->zName+7, "parameters", 10)==0 ) return 0;
+    return 1;
+  }
+  if( (pTab->tabFlags & TF_Shadow)!=0 && sqlite3ReadOnlyShadowTables(db) ){
+    return 1;
+  }
+  if( pTab->tabFlags & TF_Eponymous ){
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** This routine is called to do the work of a DROP TABLE statement.
+** pName is the name of the table to be dropped.
+*/
+SQLITE_PRIVATE void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
+  Table *pTab;
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  if( db->mallocFailed ){
+    goto exit_drop_table;
+  }
+  assert( pParse->nErr==0 );
+  assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 );
+  assert( pName->a[0].fg.isSubquery==0 );
+  if( sqlite3ReadSchema(pParse) ) goto exit_drop_table;
+  if( noErr ) db->suppressErr++;
+  assert( isView==0 || isView==LOCATE_VIEW );
+  pTab = sqlite3LocateTableItem(pParse, isView, &pName->a[0]);
+  if( noErr ) db->suppressErr--;
+
+  if( pTab==0 ){
+    if( noErr ){
+      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].u4.zDatabase);
+      sqlite3ForceNotReadOnly(pParse);
+    }
+    goto exit_drop_table;
+  }
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+
+  /* If pTab is a virtual table, call ViewGetColumnNames() to ensure
+  ** it is initialized.
+  */
+  if( IsVirtual(pTab) && sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto exit_drop_table;
+  }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  {
+    int code;
+    const char *zTab = SCHEMA_TABLE(iDb);
+    const char *zDb = db->aDb[iDb].zDbSName;
+    const char *zArg2 = 0;
+    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb)){
+      goto exit_drop_table;
+    }
+    if( isView ){
+      if( !OMIT_TEMPDB && iDb==1 ){
+        code = SQLITE_DROP_TEMP_VIEW;
+      }else{
+        code = SQLITE_DROP_VIEW;
+      }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    }else if( IsVirtual(pTab) ){
+      code = SQLITE_DROP_VTABLE;
+      zArg2 = sqlite3GetVTable(db, pTab)->pMod->zName;
+#endif
+    }else{
+      if( !OMIT_TEMPDB && iDb==1 ){
+        code = SQLITE_DROP_TEMP_TABLE;
+      }else{
+        code = SQLITE_DROP_TABLE;
+      }
+    }
+    if( sqlite3AuthCheck(pParse, code, pTab->zName, zArg2, zDb) ){
+      goto exit_drop_table;
+    }
+    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb) ){
+      goto exit_drop_table;
+    }
+  }
+#endif
+  if( tableMayNotBeDropped(db, pTab) ){
+    sqlite3ErrorMsg(pParse, "table %s may not be dropped", pTab->zName);
+    goto exit_drop_table;
+  }
+
+#ifndef SQLITE_OMIT_VIEW
+  /* Ensure DROP TABLE is not used on a view, and DROP VIEW is not used
+  ** on a table.
+  */
+  if( isView && !IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "use DROP TABLE to delete table %s", pTab->zName);
+    goto exit_drop_table;
+  }
+  if( !isView && IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "use DROP VIEW to delete view %s", pTab->zName);
+    goto exit_drop_table;
+  }
+#endif
+
+  /* Generate code to remove the table from the schema table
+  ** on disk.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3BeginWriteOperation(pParse, 1, iDb);
+    if( !isView ){
+      sqlite3ClearStatTables(pParse, iDb, "tbl", pTab->zName);
+      sqlite3FkDropTable(pParse, pName, pTab);
+    }
+    sqlite3CodeDropTable(pParse, pTab, iDb, isView);
+  }
+
+exit_drop_table:
+  sqlite3SrcListDelete(db, pName);
+}
+
+/*
+** This routine is called to create a new foreign key on the table
+** currently under construction.  pFromCol determines which columns
+** in the current table point to the foreign key.  If pFromCol==0 then
+** connect the key to the last column inserted.  pTo is the name of
+** the table referred to (a.k.a the "parent" table).  pToCol is a list
+** of tables in the parent pTo table.  flags contains all
+** information about the conflict resolution algorithms specified
+** in the ON DELETE, ON UPDATE and ON INSERT clauses.
+**
+** An FKey structure is created and added to the table currently
+** under construction in the pParse->pNewTable field.
+**
+** The foreign key is set for IMMEDIATE processing.  A subsequent call
+** to sqlite3DeferForeignKey() might change this to DEFERRED.
+*/
+SQLITE_PRIVATE void sqlite3CreateForeignKey(
+  Parse *pParse,       /* Parsing context */
+  ExprList *pFromCol,  /* Columns in this table that point to other table */
+  Token *pTo,          /* Name of the other table */
+  ExprList *pToCol,    /* Columns in the other table */
+  int flags            /* Conflict resolution algorithms. */
+){
+  sqlite3 *db = pParse->db;
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  FKey *pFKey = 0;
+  FKey *pNextTo;
+  Table *p = pParse->pNewTable;
+  i64 nByte;
+  int i;
+  int nCol;
+  char *z;
+
+  assert( pTo!=0 );
+  if( p==0 || IN_DECLARE_VTAB ) goto fk_end;
+  if( pFromCol==0 ){
+    int iCol = p->nCol-1;
+    if( NEVER(iCol<0) ) goto fk_end;
+    if( pToCol && pToCol->nExpr!=1 ){
+      sqlite3ErrorMsg(pParse, "foreign key on %s"
+         " should reference only one column of table %T",
+         p->aCol[iCol].zCnName, pTo);
+      goto fk_end;
+    }
+    nCol = 1;
+  }else if( pToCol && pToCol->nExpr!=pFromCol->nExpr ){
+    sqlite3ErrorMsg(pParse,
+        "number of columns in foreign key does not match the number of "
+        "columns in the referenced table");
+    goto fk_end;
+  }else{
+    nCol = pFromCol->nExpr;
+  }
+  nByte = sizeof(*pFKey) + (nCol-1)*sizeof(pFKey->aCol[0]) + pTo->n + 1;
+  if( pToCol ){
+    for(i=0; i<pToCol->nExpr; i++){
+      nByte += sqlite3Strlen30(pToCol->a[i].zEName) + 1;
+    }
+  }
+  pFKey = sqlite3DbMallocZero(db, nByte );
+  if( pFKey==0 ){
+    goto fk_end;
+  }
+  pFKey->pFrom = p;
+  assert( IsOrdinaryTable(p) );
+  pFKey->pNextFrom = p->u.tab.pFKey;
+  z = (char*)&pFKey->aCol[nCol];
+  pFKey->zTo = z;
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameTokenMap(pParse, (void*)z, pTo);
+  }
+  memcpy(z, pTo->z, pTo->n);
+  z[pTo->n] = 0;
+  sqlite3Dequote(z);
+  z += pTo->n+1;
+  pFKey->nCol = nCol;
+  if( pFromCol==0 ){
+    pFKey->aCol[0].iFrom = p->nCol-1;
+  }else{
+    for(i=0; i<nCol; i++){
+      int j;
+      for(j=0; j<p->nCol; j++){
+        if( sqlite3StrICmp(p->aCol[j].zCnName, pFromCol->a[i].zEName)==0 ){
+          pFKey->aCol[i].iFrom = j;
+          break;
+        }
+      }
+      if( j>=p->nCol ){
+        sqlite3ErrorMsg(pParse,
+          "unknown column \"%s\" in foreign key definition",
+          pFromCol->a[i].zEName);
+        goto fk_end;
+      }
+      if( IN_RENAME_OBJECT ){
+        sqlite3RenameTokenRemap(pParse, &pFKey->aCol[i], pFromCol->a[i].zEName);
+      }
+    }
+  }
+  if( pToCol ){
+    for(i=0; i<nCol; i++){
+      int n = sqlite3Strlen30(pToCol->a[i].zEName);
+      pFKey->aCol[i].zCol = z;
+      if( IN_RENAME_OBJECT ){
+        sqlite3RenameTokenRemap(pParse, z, pToCol->a[i].zEName);
+      }
+      memcpy(z, pToCol->a[i].zEName, n);
+      z[n] = 0;
+      z += n+1;
+    }
+  }
+  pFKey->isDeferred = 0;
+  pFKey->aAction[0] = (u8)(flags & 0xff);            /* ON DELETE action */
+  pFKey->aAction[1] = (u8)((flags >> 8 ) & 0xff);    /* ON UPDATE action */
+
+  assert( sqlite3SchemaMutexHeld(db, 0, p->pSchema) );
+  pNextTo = (FKey *)sqlite3HashInsert(&p->pSchema->fkeyHash,
+      pFKey->zTo, (void *)pFKey
+  );
+  if( pNextTo==pFKey ){
+    sqlite3OomFault(db);
+    goto fk_end;
+  }
+  if( pNextTo ){
+    assert( pNextTo->pPrevTo==0 );
+    pFKey->pNextTo = pNextTo;
+    pNextTo->pPrevTo = pFKey;
+  }
+
+  /* Link the foreign key to the table as the last step.
+  */
+  assert( IsOrdinaryTable(p) );
+  p->u.tab.pFKey = pFKey;
+  pFKey = 0;
+
+fk_end:
+  sqlite3DbFree(db, pFKey);
+#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */
+  sqlite3ExprListDelete(db, pFromCol);
+  sqlite3ExprListDelete(db, pToCol);
+}
+
+/*
+** This routine is called when an INITIALLY IMMEDIATE or INITIALLY DEFERRED
+** clause is seen as part of a foreign key definition.  The isDeferred
+** parameter is 1 for INITIALLY DEFERRED and 0 for INITIALLY IMMEDIATE.
+** The behavior of the most recently created foreign key is adjusted
+** accordingly.
+*/
+SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse *pParse, int isDeferred){
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  Table *pTab;
+  FKey *pFKey;
+  if( (pTab = pParse->pNewTable)==0 ) return;
+  if( NEVER(!IsOrdinaryTable(pTab)) ) return;
+  if( (pFKey = pTab->u.tab.pFKey)==0 ) return;
+  assert( isDeferred==0 || isDeferred==1 ); /* EV: R-30323-21917 */
+  pFKey->isDeferred = (u8)isDeferred;
+#endif
+}
+
+/*
+** Generate code that will erase and refill index *pIdx.  This is
+** used to initialize a newly created index or to recompute the
+** content of an index in response to a REINDEX command.
+**
+** if memRootPage is not negative, it means that the index is newly
+** created.  The register specified by memRootPage contains the
+** root page number of the index.  If memRootPage is negative, then
+** the index already exists and must be cleared before being refilled and
+** the root page number of the index is taken from pIndex->tnum.
+*/
+static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
+  Table *pTab = pIndex->pTable;  /* The table that is indexed */
+  int iTab = pParse->nTab++;     /* Btree cursor used for pTab */
+  int iIdx = pParse->nTab++;     /* Btree cursor used for pIndex */
+  int iSorter;                   /* Cursor opened by OpenSorter (if in use) */
+  int addr1;                     /* Address of top of loop */
+  int addr2;                     /* Address to jump to for next iteration */
+  Pgno tnum;                     /* Root page of index */
+  int iPartIdxLabel;             /* Jump to this label to skip a row */
+  Vdbe *v;                       /* Generate code into this virtual machine */
+  KeyInfo *pKey;                 /* KeyInfo for index */
+  int regRecord;                 /* Register holding assembled index record */
+  sqlite3 *db = pParse->db;      /* The database connection */
+  int iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( sqlite3AuthCheck(pParse, SQLITE_REINDEX, pIndex->zName, 0,
+      db->aDb[iDb].zDbSName ) ){
+    return;
+  }
+#endif
+
+  /* Require a write-lock on the table to perform this operation */
+  sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName);
+
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) return;
+  if( memRootPage>=0 ){
+    tnum = (Pgno)memRootPage;
+  }else{
+    tnum = pIndex->tnum;
+  }
+  pKey = sqlite3KeyInfoOfIndex(pParse, pIndex);
+  assert( pKey!=0 || pParse->nErr );
+
+  /* Open the sorter cursor if we are to use one. */
+  iSorter = pParse->nTab++;
+  sqlite3VdbeAddOp4(v, OP_SorterOpen, iSorter, 0, pIndex->nKeyCol, (char*)
+                    sqlite3KeyInfoRef(pKey), P4_KEYINFO);
+
+  /* Open the table. Loop through all rows of the table, inserting index
+  ** records into the sorter. */
+  sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
+  addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0); VdbeCoverage(v);
+  regRecord = sqlite3GetTempReg(pParse);
+  sqlite3MultiWrite(pParse);
+
+  sqlite3GenerateIndexKey(pParse,pIndex,iTab,regRecord,0,&iPartIdxLabel,0,0);
+  sqlite3VdbeAddOp2(v, OP_SorterInsert, iSorter, regRecord);
+  sqlite3ResolvePartIdxLabel(pParse, iPartIdxLabel);
+  sqlite3VdbeAddOp2(v, OP_Next, iTab, addr1+1); VdbeCoverage(v);
+  sqlite3VdbeJumpHere(v, addr1);
+  if( memRootPage<0 ) sqlite3VdbeAddOp2(v, OP_Clear, tnum, iDb);
+  sqlite3VdbeAddOp4(v, OP_OpenWrite, iIdx, (int)tnum, iDb,
+                    (char *)pKey, P4_KEYINFO);
+  sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR|((memRootPage>=0)?OPFLAG_P2ISREG:0));
+
+  addr1 = sqlite3VdbeAddOp2(v, OP_SorterSort, iSorter, 0); VdbeCoverage(v);
+  if( IsUniqueIndex(pIndex) ){
+    int j2 = sqlite3VdbeGoto(v, 1);
+    addr2 = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeVerifyAbortable(v, OE_Abort);
+    sqlite3VdbeAddOp4Int(v, OP_SorterCompare, iSorter, j2, regRecord,
+                         pIndex->nKeyCol); VdbeCoverage(v);
+    sqlite3UniqueConstraint(pParse, OE_Abort, pIndex);
+    sqlite3VdbeJumpHere(v, j2);
+  }else{
+    /* Most CREATE INDEX and REINDEX statements that are not UNIQUE can not
+    ** abort. The exception is if one of the indexed expressions contains a
+    ** user function that throws an exception when it is evaluated. But the
+    ** overhead of adding a statement journal to a CREATE INDEX statement is
+    ** very small (since most of the pages written do not contain content that
+    ** needs to be restored if the statement aborts), so we call
+    ** sqlite3MayAbort() for all CREATE INDEX statements.  */
+    sqlite3MayAbort(pParse);
+    addr2 = sqlite3VdbeCurrentAddr(v);
+  }
+  sqlite3VdbeAddOp3(v, OP_SorterData, iSorter, regRecord, iIdx);
+  if( !pIndex->bAscKeyBug ){
+    /* This OP_SeekEnd opcode makes index insert for a REINDEX go much
+    ** faster by avoiding unnecessary seeks.  But the optimization does
+    ** not work for UNIQUE constraint indexes on WITHOUT ROWID tables
+    ** with DESC primary keys, since those indexes have there keys in
+    ** a different order from the main table.
+    ** See ticket: https://www.sqlite.org/src/info/bba7b69f9849b5bf
+    */
+    sqlite3VdbeAddOp1(v, OP_SeekEnd, iIdx);
+  }
+  sqlite3VdbeAddOp2(v, OP_IdxInsert, iIdx, regRecord);
+  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+  sqlite3ReleaseTempReg(pParse, regRecord);
+  sqlite3VdbeAddOp2(v, OP_SorterNext, iSorter, addr2); VdbeCoverage(v);
+  sqlite3VdbeJumpHere(v, addr1);
+
+  sqlite3VdbeAddOp1(v, OP_Close, iTab);
+  sqlite3VdbeAddOp1(v, OP_Close, iIdx);
+  sqlite3VdbeAddOp1(v, OP_Close, iSorter);
+}
+
+/*
+** Allocate heap space to hold an Index object with nCol columns.
+**
+** Increase the allocation size to provide an extra nExtra bytes
+** of 8-byte aligned space after the Index object and return a
+** pointer to this extra space in *ppExtra.
+*/
+SQLITE_PRIVATE Index *sqlite3AllocateIndexObject(
+  sqlite3 *db,         /* Database connection */
+  i16 nCol,            /* Total number of columns in the index */
+  int nExtra,          /* Number of bytes of extra space to alloc */
+  char **ppExtra       /* Pointer to the "extra" space */
+){
+  Index *p;            /* Allocated index object */
+  int nByte;           /* Bytes of space for Index object + arrays */
+
+  nByte = ROUND8(sizeof(Index)) +              /* Index structure  */
+          ROUND8(sizeof(char*)*nCol) +         /* Index.azColl     */
+          ROUND8(sizeof(LogEst)*(nCol+1) +     /* Index.aiRowLogEst   */
+                 sizeof(i16)*nCol +            /* Index.aiColumn   */
+                 sizeof(u8)*nCol);             /* Index.aSortOrder */
+  p = sqlite3DbMallocZero(db, nByte + nExtra);
+  if( p ){
+    char *pExtra = ((char*)p)+ROUND8(sizeof(Index));
+    p->azColl = (const char**)pExtra; pExtra += ROUND8(sizeof(char*)*nCol);
+    p->aiRowLogEst = (LogEst*)pExtra; pExtra += sizeof(LogEst)*(nCol+1);
+    p->aiColumn = (i16*)pExtra;       pExtra += sizeof(i16)*nCol;
+    p->aSortOrder = (u8*)pExtra;
+    p->nColumn = nCol;
+    p->nKeyCol = nCol - 1;
+    *ppExtra = ((char*)p) + nByte;
+  }
+  return p;
+}
+
+/*
+** If expression list pList contains an expression that was parsed with
+** an explicit "NULLS FIRST" or "NULLS LAST" clause, leave an error in
+** pParse and return non-zero. Otherwise, return zero.
+*/
+SQLITE_PRIVATE int sqlite3HasExplicitNulls(Parse *pParse, ExprList *pList){
+  if( pList ){
+    int i;
+    for(i=0; i<pList->nExpr; i++){
+      if( pList->a[i].fg.bNulls ){
+        u8 sf = pList->a[i].fg.sortFlags;
+        sqlite3ErrorMsg(pParse, "unsupported use of NULLS %s",
+            (sf==0 || sf==3) ? "FIRST" : "LAST"
+        );
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Create a new index for an SQL table.  pName1.pName2 is the name of the index
+** and pTblList is the name of the table that is to be indexed.  Both will
+** be NULL for a primary key or an index that is created to satisfy a
+** UNIQUE constraint.  If pTable and pIndex are NULL, use pParse->pNewTable
+** as the table to be indexed.  pParse->pNewTable is a table that is
+** currently being constructed by a CREATE TABLE statement.
+**
+** pList is a list of columns to be indexed.  pList will be NULL if this
+** is a primary key or unique-constraint on the most recent column added
+** to the table currently under construction.
+*/
+SQLITE_PRIVATE void sqlite3CreateIndex(
+  Parse *pParse,     /* All information about this parse */
+  Token *pName1,     /* First part of index name. May be NULL */
+  Token *pName2,     /* Second part of index name. May be NULL */
+  SrcList *pTblName, /* Table to index. Use pParse->pNewTable if 0 */
+  ExprList *pList,   /* A list of columns to be indexed */
+  int onError,       /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
+  Token *pStart,     /* The CREATE token that begins this statement */
+  Expr *pPIWhere,    /* WHERE clause for partial indices */
+  int sortOrder,     /* Sort order of primary key when pList==NULL */
+  int ifNotExist,    /* Omit error if index already exists */
+  u8 idxType         /* The index type */
+){
+  Table *pTab = 0;     /* Table to be indexed */
+  Index *pIndex = 0;   /* The index to be created */
+  char *zName = 0;     /* Name of the index */
+  int nName;           /* Number of characters in zName */
+  int i, j;
+  DbFixer sFix;        /* For assigning database names to pTable */
+  int sortOrderMask;   /* 1 to honor DESC in index.  0 to ignore. */
+  sqlite3 *db = pParse->db;
+  Db *pDb;             /* The specific table containing the indexed database */
+  int iDb;             /* Index of the database that is being written */
+  Token *pName = 0;    /* Unqualified name of the index to create */
+  struct ExprList_item *pListItem; /* For looping over pList */
+  int nExtra = 0;                  /* Space allocated for zExtra[] */
+  int nExtraCol;                   /* Number of extra columns needed */
+  char *zExtra = 0;                /* Extra space after the Index object */
+  Index *pPk = 0;      /* PRIMARY KEY index for WITHOUT ROWID tables */
+
+  assert( db->pParse==pParse );
+  if( pParse->nErr ){
+    goto exit_create_index;
+  }
+  assert( db->mallocFailed==0 );
+  if( IN_DECLARE_VTAB && idxType!=SQLITE_IDXTYPE_PRIMARYKEY ){
+    goto exit_create_index;
+  }
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    goto exit_create_index;
+  }
+  if( sqlite3HasExplicitNulls(pParse, pList) ){
+    goto exit_create_index;
+  }
+
+  /*
+  ** Find the table that is to be indexed.  Return early if not found.
+  */
+  if( pTblName!=0 ){
+
+    /* Use the two-part index name to determine the database
+    ** to search for the table. 'Fix' the table name to this db
+    ** before looking up the table.
+    */
+    assert( pName1 && pName2 );
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+    if( iDb<0 ) goto exit_create_index;
+    assert( pName && pName->z );
+
+#ifndef SQLITE_OMIT_TEMPDB
+    /* If the index name was unqualified, check if the table
+    ** is a temp table. If so, set the database to 1. Do not do this
+    ** if initializing a database schema.
+    */
+    if( !db->init.busy ){
+      pTab = sqlite3SrcListLookup(pParse, pTblName);
+      if( pName2->n==0 && pTab && pTab->pSchema==db->aDb[1].pSchema ){
+        iDb = 1;
+      }
+    }
+#endif
+
+    sqlite3FixInit(&sFix, pParse, iDb, "index", pName);
+    if( sqlite3FixSrcList(&sFix, pTblName) ){
+      /* Because the parser constructs pTblName from a single identifier,
+      ** sqlite3FixSrcList can never fail. */
+      assert(0);
+    }
+    pTab = sqlite3LocateTableItem(pParse, 0, &pTblName->a[0]);
+    assert( db->mallocFailed==0 || pTab==0 );
+    if( pTab==0 ) goto exit_create_index;
+    if( iDb==1 && db->aDb[iDb].pSchema!=pTab->pSchema ){
+      sqlite3ErrorMsg(pParse,
+           "cannot create a TEMP index on non-TEMP table \"%s\"",
+           pTab->zName);
+      goto exit_create_index;
+    }
+    if( !HasRowid(pTab) ) pPk = sqlite3PrimaryKeyIndex(pTab);
+  }else{
+    assert( pName==0 );
+    assert( pStart==0 );
+    pTab = pParse->pNewTable;
+    if( !pTab ) goto exit_create_index;
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  }
+  pDb = &db->aDb[iDb];
+
+  assert( pTab!=0 );
+  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0
+       && db->init.busy==0
+       && pTblName!=0
+  ){
+    sqlite3ErrorMsg(pParse, "table %s may not be indexed", pTab->zName);
+    goto exit_create_index;
+  }
+#ifndef SQLITE_OMIT_VIEW
+  if( IsView(pTab) ){
+    sqlite3ErrorMsg(pParse, "views may not be indexed");
+    goto exit_create_index;
+  }
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pTab) ){
+    sqlite3ErrorMsg(pParse, "virtual tables may not be indexed");
+    goto exit_create_index;
+  }
+#endif
+
+  /*
+  ** Find the name of the index.  Make sure there is not already another
+  ** index or table with the same name.
+  **
+  ** Exception:  If we are reading the names of permanent indices from the
+  ** sqlite_schema table (because some other process changed the schema) and
+  ** one of the index names collides with the name of a temporary table or
+  ** index, then we will continue to process this index.
+  **
+  ** If pName==0 it means that we are
+  ** dealing with a primary key or UNIQUE constraint.  We have to invent our
+  ** own name.
+  */
+  if( pName ){
+    zName = sqlite3NameFromToken(db, pName);
+    if( zName==0 ) goto exit_create_index;
+    assert( pName->z!=0 );
+    if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName,"index",pTab->zName) ){
+      goto exit_create_index;
+    }
+    if( !IN_RENAME_OBJECT ){
+      if( !db->init.busy ){
+        if( sqlite3FindTable(db, zName, pDb->zDbSName)!=0 ){
+          sqlite3ErrorMsg(pParse, "there is already a table named %s", zName);
+          goto exit_create_index;
+        }
+      }
+      if( sqlite3FindIndex(db, zName, pDb->zDbSName)!=0 ){
+        if( !ifNotExist ){
+          sqlite3ErrorMsg(pParse, "index %s already exists", zName);
+        }else{
+          assert( !db->init.busy );
+          sqlite3CodeVerifySchema(pParse, iDb);
+          sqlite3ForceNotReadOnly(pParse);
+        }
+        goto exit_create_index;
+      }
+    }
+  }else{
+    int n;
+    Index *pLoop;
+    for(pLoop=pTab->pIndex, n=1; pLoop; pLoop=pLoop->pNext, n++){}
+    zName = sqlite3MPrintf(db, "sqlite_autoindex_%s_%d", pTab->zName, n);
+    if( zName==0 ){
+      goto exit_create_index;
+    }
+
+    /* Automatic index names generated from within sqlite3_declare_vtab()
+    ** must have names that are distinct from normal automatic index names.
+    ** The following statement converts "sqlite3_autoindex..." into
+    ** "sqlite3_butoindex..." in order to make the names distinct.
+    ** The "vtab_err.test" test demonstrates the need of this statement. */
+    if( IN_SPECIAL_PARSE ) zName[7]++;
+  }
+
+  /* Check for authorization to create an index.
+  */
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( !IN_RENAME_OBJECT ){
+    const char *zDb = pDb->zDbSName;
+    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iDb), 0, zDb) ){
+      goto exit_create_index;
+    }
+    i = SQLITE_CREATE_INDEX;
+    if( !OMIT_TEMPDB && iDb==1 ) i = SQLITE_CREATE_TEMP_INDEX;
+    if( sqlite3AuthCheck(pParse, i, zName, pTab->zName, zDb) ){
+      goto exit_create_index;
+    }
+  }
+#endif
+
+  /* If pList==0, it means this routine was called to make a primary
+  ** key out of the last column added to the table under construction.
+  ** So create a fake list to simulate this.
+  */
+  if( pList==0 ){
+    Token prevCol;
+    Column *pCol = &pTab->aCol[pTab->nCol-1];
+    pCol->colFlags |= COLFLAG_UNIQUE;
+    sqlite3TokenInit(&prevCol, pCol->zCnName);
+    pList = sqlite3ExprListAppend(pParse, 0,
+              sqlite3ExprAlloc(db, TK_ID, &prevCol, 0));
+    if( pList==0 ) goto exit_create_index;
+    assert( pList->nExpr==1 );
+    sqlite3ExprListSetSortOrder(pList, sortOrder, SQLITE_SO_UNDEFINED);
+  }else{
+    sqlite3ExprListCheckLength(pParse, pList, "index");
+    if( pParse->nErr ) goto exit_create_index;
+  }
+
+  /* Figure out how many bytes of space are required to store explicitly
+  ** specified collation sequence names.
+  */
+  for(i=0; i<pList->nExpr; i++){
+    Expr *pExpr = pList->a[i].pExpr;
+    assert( pExpr!=0 );
+    if( pExpr->op==TK_COLLATE ){
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      nExtra += (1 + sqlite3Strlen30(pExpr->u.zToken));
+    }
+  }
+
+  /*
+  ** Allocate the index structure.
+  */
+  nName = sqlite3Strlen30(zName);
+  nExtraCol = pPk ? pPk->nKeyCol : 1;
+  assert( pList->nExpr + nExtraCol <= 32767 /* Fits in i16 */ );
+  pIndex = sqlite3AllocateIndexObject(db, pList->nExpr + nExtraCol,
+                                      nName + nExtra + 1, &zExtra);
+  if( db->mallocFailed ){
+    goto exit_create_index;
+  }
+  assert( EIGHT_BYTE_ALIGNMENT(pIndex->aiRowLogEst) );
+  assert( EIGHT_BYTE_ALIGNMENT(pIndex->azColl) );
+  pIndex->zName = zExtra;
+  zExtra += nName + 1;
+  memcpy(pIndex->zName, zName, nName+1);
+  pIndex->pTable = pTab;
+  pIndex->onError = (u8)onError;
+  pIndex->uniqNotNull = onError!=OE_None;
+  pIndex->idxType = idxType;
+  pIndex->pSchema = db->aDb[iDb].pSchema;
+  pIndex->nKeyCol = pList->nExpr;
+  if( pPIWhere ){
+    sqlite3ResolveSelfReference(pParse, pTab, NC_PartIdx, pPIWhere, 0);
+    pIndex->pPartIdxWhere = pPIWhere;
+    pPIWhere = 0;
+  }
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+
+  /* Check to see if we should honor DESC requests on index columns
+  */
+  if( pDb->pSchema->file_format>=4 ){
+    sortOrderMask = -1;   /* Honor DESC */
+  }else{
+    sortOrderMask = 0;    /* Ignore DESC */
+  }
+
+  /* Analyze the list of expressions that form the terms of the index and
+  ** report any errors.  In the common case where the expression is exactly
+  ** a table column, store that column in aiColumn[].  For general expressions,
+  ** populate pIndex->aColExpr and store XN_EXPR (-2) in aiColumn[].
+  **
+  ** TODO: Issue a warning if two or more columns of the index are identical.
+  ** TODO: Issue a warning if the table primary key is used as part of the
+  ** index key.
+  */
+  pListItem = pList->a;
+  if( IN_RENAME_OBJECT ){
+    pIndex->aColExpr = pList;
+    pList = 0;
+  }
+  for(i=0; i<pIndex->nKeyCol; i++, pListItem++){
+    Expr *pCExpr;                  /* The i-th index expression */
+    int requestedSortOrder;        /* ASC or DESC on the i-th expression */
+    const char *zColl;             /* Collation sequence name */
+
+    sqlite3StringToId(pListItem->pExpr);
+    sqlite3ResolveSelfReference(pParse, pTab, NC_IdxExpr, pListItem->pExpr, 0);
+    if( pParse->nErr ) goto exit_create_index;
+    pCExpr = sqlite3ExprSkipCollate(pListItem->pExpr);
+    if( pCExpr->op!=TK_COLUMN ){
+      if( pTab==pParse->pNewTable ){
+        sqlite3ErrorMsg(pParse, "expressions prohibited in PRIMARY KEY and "
+                                "UNIQUE constraints");
+        goto exit_create_index;
+      }
+      if( pIndex->aColExpr==0 ){
+        pIndex->aColExpr = pList;
+        pList = 0;
+      }
+      j = XN_EXPR;
+      pIndex->aiColumn[i] = XN_EXPR;
+      pIndex->uniqNotNull = 0;
+      pIndex->bHasExpr = 1;
+    }else{
+      j = pCExpr->iColumn;
+      assert( j<=0x7fff );
+      if( j<0 ){
+        j = pTab->iPKey;
+        pIndex->bIdxRowid = 1;
+      }else{
+        if( pTab->aCol[j].notNull==0 ){
+          pIndex->uniqNotNull = 0;
+        }
+        if( pTab->aCol[j].colFlags & COLFLAG_VIRTUAL ){
+          pIndex->bHasVCol = 1;
+          pIndex->bHasExpr = 1;
+        }
+      }
+      pIndex->aiColumn[i] = (i16)j;
+    }
+    zColl = 0;
+    if( pListItem->pExpr->op==TK_COLLATE ){
+      int nColl;
+      assert( !ExprHasProperty(pListItem->pExpr, EP_IntValue) );
+      zColl = pListItem->pExpr->u.zToken;
+      nColl = sqlite3Strlen30(zColl) + 1;
+      assert( nExtra>=nColl );
+      memcpy(zExtra, zColl, nColl);
+      zColl = zExtra;
+      zExtra += nColl;
+      nExtra -= nColl;
+    }else if( j>=0 ){
+      zColl = sqlite3ColumnColl(&pTab->aCol[j]);
+    }
+    if( !zColl ) zColl = sqlite3StrBINARY;
+    if( !db->init.busy && !sqlite3LocateCollSeq(pParse, zColl) ){
+      goto exit_create_index;
+    }
+    pIndex->azColl[i] = zColl;
+    requestedSortOrder = pListItem->fg.sortFlags & sortOrderMask;
+    pIndex->aSortOrder[i] = (u8)requestedSortOrder;
+  }
+
+  /* Append the table key to the end of the index.  For WITHOUT ROWID
+  ** tables (when pPk!=0) this will be the declared PRIMARY KEY.  For
+  ** normal tables (when pPk==0) this will be the rowid.
+  */
+  if( pPk ){
+    for(j=0; j<pPk->nKeyCol; j++){
+      int x = pPk->aiColumn[j];
+      assert( x>=0 );
+      if( isDupColumn(pIndex, pIndex->nKeyCol, pPk, j) ){
+        pIndex->nColumn--;
+      }else{
+        testcase( hasColumn(pIndex->aiColumn,pIndex->nKeyCol,x) );
+        pIndex->aiColumn[i] = x;
+        pIndex->azColl[i] = pPk->azColl[j];
+        pIndex->aSortOrder[i] = pPk->aSortOrder[j];
+        i++;
+      }
+    }
+    assert( i==pIndex->nColumn );
+  }else{
+    pIndex->aiColumn[i] = XN_ROWID;
+    pIndex->azColl[i] = sqlite3StrBINARY;
+  }
+  sqlite3DefaultRowEst(pIndex);
+  if( pParse->pNewTable==0 ) estimateIndexWidth(pIndex);
+
+  /* If this index contains every column of its table, then mark
+  ** it as a covering index */
+  assert( HasRowid(pTab)
+      || pTab->iPKey<0 || sqlite3TableColumnToIndex(pIndex, pTab->iPKey)>=0 );
+  recomputeColumnsNotIndexed(pIndex);
+  if( pTblName!=0 && pIndex->nColumn>=pTab->nCol ){
+    pIndex->isCovering = 1;
+    for(j=0; j<pTab->nCol; j++){
+      if( j==pTab->iPKey ) continue;
+      if( sqlite3TableColumnToIndex(pIndex,j)>=0 ) continue;
+      pIndex->isCovering = 0;
+      break;
+    }
+  }
+
+  if( pTab==pParse->pNewTable ){
+    /* This routine has been called to create an automatic index as a
+    ** result of a PRIMARY KEY or UNIQUE clause on a column definition, or
+    ** a PRIMARY KEY or UNIQUE clause following the column definitions.
+    ** i.e. one of:
+    **
+    ** CREATE TABLE t(x PRIMARY KEY, y);
+    ** CREATE TABLE t(x, y, UNIQUE(x, y));
+    **
+    ** Either way, check to see if the table already has such an index. If
+    ** so, don't bother creating this one. This only applies to
+    ** automatically created indices. Users can do as they wish with
+    ** explicit indices.
+    **
+    ** Two UNIQUE or PRIMARY KEY constraints are considered equivalent
+    ** (and thus suppressing the second one) even if they have different
+    ** sort orders.
+    **
+    ** If there are different collating sequences or if the columns of
+    ** the constraint occur in different orders, then the constraints are
+    ** considered distinct and both result in separate indices.
+    */
+    Index *pIdx;
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      int k;
+      assert( IsUniqueIndex(pIdx) );
+      assert( pIdx->idxType!=SQLITE_IDXTYPE_APPDEF );
+      assert( IsUniqueIndex(pIndex) );
+
+      if( pIdx->nKeyCol!=pIndex->nKeyCol ) continue;
+      for(k=0; k<pIdx->nKeyCol; k++){
+        const char *z1;
+        const char *z2;
+        assert( pIdx->aiColumn[k]>=0 );
+        if( pIdx->aiColumn[k]!=pIndex->aiColumn[k] ) break;
+        z1 = pIdx->azColl[k];
+        z2 = pIndex->azColl[k];
+        if( sqlite3StrICmp(z1, z2) ) break;
+      }
+      if( k==pIdx->nKeyCol ){
+        if( pIdx->onError!=pIndex->onError ){
+          /* This constraint creates the same index as a previous
+          ** constraint specified somewhere in the CREATE TABLE statement.
+          ** However the ON CONFLICT clauses are different. If both this
+          ** constraint and the previous equivalent constraint have explicit
+          ** ON CONFLICT clauses this is an error. Otherwise, use the
+          ** explicitly specified behavior for the index.
+          */
+          if( !(pIdx->onError==OE_Default || pIndex->onError==OE_Default) ){
+            sqlite3ErrorMsg(pParse,
+                "conflicting ON CONFLICT clauses specified", 0);
+          }
+          if( pIdx->onError==OE_Default ){
+            pIdx->onError = pIndex->onError;
+          }
+        }
+        if( idxType==SQLITE_IDXTYPE_PRIMARYKEY ) pIdx->idxType = idxType;
+        if( IN_RENAME_OBJECT ){
+          pIndex->pNext = pParse->pNewIndex;
+          pParse->pNewIndex = pIndex;
+          pIndex = 0;
+        }
+        goto exit_create_index;
+      }
+    }
+  }
+
+  if( !IN_RENAME_OBJECT ){
+
+    /* Link the new Index structure to its table and to the other
+    ** in-memory database structures.
+    */
+    assert( pParse->nErr==0 );
+    if( db->init.busy ){
+      Index *p;
+      assert( !IN_SPECIAL_PARSE );
+      assert( sqlite3SchemaMutexHeld(db, 0, pIndex->pSchema) );
+      if( pTblName!=0 ){
+        pIndex->tnum = db->init.newTnum;
+        if( sqlite3IndexHasDuplicateRootPage(pIndex) ){
+          sqlite3ErrorMsg(pParse, "invalid rootpage");
+          pParse->rc = SQLITE_CORRUPT_BKPT;
+          goto exit_create_index;
+        }
+      }
+      p = sqlite3HashInsert(&pIndex->pSchema->idxHash,
+          pIndex->zName, pIndex);
+      if( p ){
+        assert( p==pIndex );  /* Malloc must have failed */
+        sqlite3OomFault(db);
+        goto exit_create_index;
+      }
+      db->mDbFlags |= DBFLAG_SchemaChange;
+    }
+
+    /* If this is the initial CREATE INDEX statement (or CREATE TABLE if the
+    ** index is an implied index for a UNIQUE or PRIMARY KEY constraint) then
+    ** emit code to allocate the index rootpage on disk and make an entry for
+    ** the index in the sqlite_schema table and populate the index with
+    ** content.  But, do not do this if we are simply reading the sqlite_schema
+    ** table to parse the schema, or if this index is the PRIMARY KEY index
+    ** of a WITHOUT ROWID table.
+    **
+    ** If pTblName==0 it means this index is generated as an implied PRIMARY KEY
+    ** or UNIQUE index in a CREATE TABLE statement.  Since the table
+    ** has just been created, it contains no data and the index initialization
+    ** step can be skipped.
+    */
+    else if( HasRowid(pTab) || pTblName!=0 ){
+      Vdbe *v;
+      char *zStmt;
+      int iMem = ++pParse->nMem;
+
+      v = sqlite3GetVdbe(pParse);
+      if( v==0 ) goto exit_create_index;
+
+      sqlite3BeginWriteOperation(pParse, 1, iDb);
+
+      /* Create the rootpage for the index using CreateIndex. But before
+      ** doing so, code a Noop instruction and store its address in
+      ** Index.tnum. This is required in case this index is actually a
+      ** PRIMARY KEY and the table is actually a WITHOUT ROWID table. In
+      ** that case the convertToWithoutRowidTable() routine will replace
+      ** the Noop with a Goto to jump over the VDBE code generated below. */
+      pIndex->tnum = (Pgno)sqlite3VdbeAddOp0(v, OP_Noop);
+      sqlite3VdbeAddOp3(v, OP_CreateBtree, iDb, iMem, BTREE_BLOBKEY);
+
+      /* Gather the complete text of the CREATE INDEX statement into
+      ** the zStmt variable
+      */
+      assert( pName!=0 || pStart==0 );
+      if( pStart ){
+        int n = (int)(pParse->sLastToken.z - pName->z) + pParse->sLastToken.n;
+        if( pName->z[n-1]==';' ) n--;
+        /* A named index with an explicit CREATE INDEX statement */
+        zStmt = sqlite3MPrintf(db, "CREATE%s INDEX %.*s",
+            onError==OE_None ? "" : " UNIQUE", n, pName->z);
+      }else{
+        /* An automatic index created by a PRIMARY KEY or UNIQUE constraint */
+        /* zStmt = sqlite3MPrintf(""); */
+        zStmt = 0;
+      }
+
+      /* Add an entry in sqlite_schema for this index
+      */
+      sqlite3NestedParse(pParse,
+         "INSERT INTO %Q." LEGACY_SCHEMA_TABLE " VALUES('index',%Q,%Q,#%d,%Q);",
+         db->aDb[iDb].zDbSName,
+         pIndex->zName,
+         pTab->zName,
+         iMem,
+         zStmt
+      );
+      sqlite3DbFree(db, zStmt);
+
+      /* Fill the index with data and reparse the schema. Code an OP_Expire
+      ** to invalidate all pre-compiled statements.
+      */
+      if( pTblName ){
+        sqlite3RefillIndex(pParse, pIndex, iMem);
+        sqlite3ChangeCookie(pParse, iDb);
+        sqlite3VdbeAddParseSchemaOp(v, iDb,
+            sqlite3MPrintf(db, "name='%q' AND type='index'", pIndex->zName), 0);
+        sqlite3VdbeAddOp2(v, OP_Expire, 0, 1);
+      }
+
+      sqlite3VdbeJumpHere(v, (int)pIndex->tnum);
+    }
+  }
+  if( db->init.busy || pTblName==0 ){
+    pIndex->pNext = pTab->pIndex;
+    pTab->pIndex = pIndex;
+    pIndex = 0;
+  }
+  else if( IN_RENAME_OBJECT ){
+    assert( pParse->pNewIndex==0 );
+    pParse->pNewIndex = pIndex;
+    pIndex = 0;
+  }
+
+  /* Clean up before exiting */
+exit_create_index:
+  if( pIndex ) sqlite3FreeIndex(db, pIndex);
+  if( pTab ){
+    /* Ensure all REPLACE indexes on pTab are at the end of the pIndex list.
+    ** The list was already ordered when this routine was entered, so at this
+    ** point at most a single index (the newly added index) will be out of
+    ** order.  So we have to reorder at most one index. */
+    Index **ppFrom;
+    Index *pThis;
+    for(ppFrom=&pTab->pIndex; (pThis = *ppFrom)!=0; ppFrom=&pThis->pNext){
+      Index *pNext;
+      if( pThis->onError!=OE_Replace ) continue;
+      while( (pNext = pThis->pNext)!=0 && pNext->onError!=OE_Replace ){
+        *ppFrom = pNext;
+        pThis->pNext = pNext->pNext;
+        pNext->pNext = pThis;
+        ppFrom = &pNext->pNext;
+      }
+      break;
+    }
+#ifdef SQLITE_DEBUG
+    /* Verify that all REPLACE indexes really are now at the end
+    ** of the index list.  In other words, no other index type ever
+    ** comes after a REPLACE index on the list. */
+    for(pThis = pTab->pIndex; pThis; pThis=pThis->pNext){
+      assert( pThis->onError!=OE_Replace
+           || pThis->pNext==0
+           || pThis->pNext->onError==OE_Replace );
+    }
+#endif
+  }
+  sqlite3ExprDelete(db, pPIWhere);
+  sqlite3ExprListDelete(db, pList);
+  sqlite3SrcListDelete(db, pTblName);
+  sqlite3DbFree(db, zName);
+}
+
+/*
+** Fill the Index.aiRowEst[] array with default information - information
+** to be used when we have not run the ANALYZE command.
+**
+** aiRowEst[0] is supposed to contain the number of elements in the index.
+** Since we do not know, guess 1 million.  aiRowEst[1] is an estimate of the
+** number of rows in the table that match any particular value of the
+** first column of the index.  aiRowEst[2] is an estimate of the number
+** of rows that match any particular combination of the first 2 columns
+** of the index.  And so forth.  It must always be the case that
+*
+**           aiRowEst[N]<=aiRowEst[N-1]
+**           aiRowEst[N]>=1
+**
+** Apart from that, we have little to go on besides intuition as to
+** how aiRowEst[] should be initialized.  The numbers generated here
+** are based on typical values found in actual indices.
+*/
+SQLITE_PRIVATE void sqlite3DefaultRowEst(Index *pIdx){
+               /*                10,  9,  8,  7,  6 */
+  static const LogEst aVal[] = { 33, 32, 30, 28, 26 };
+  LogEst *a = pIdx->aiRowLogEst;
+  LogEst x;
+  int nCopy = MIN(ArraySize(aVal), pIdx->nKeyCol);
+  int i;
+
+  /* Indexes with default row estimates should not have stat1 data */
+  assert( !pIdx->hasStat1 );
+
+  /* Set the first entry (number of rows in the index) to the estimated
+  ** number of rows in the table, or half the number of rows in the table
+  ** for a partial index.
+  **
+  ** 2020-05-27:  If some of the stat data is coming from the sqlite_stat1
+  ** table but other parts we are having to guess at, then do not let the
+  ** estimated number of rows in the table be less than 1000 (LogEst 99).
+  ** Failure to do this can cause the indexes for which we do not have
+  ** stat1 data to be ignored by the query planner.
+  */
+  x = pIdx->pTable->nRowLogEst;
+  assert( 99==sqlite3LogEst(1000) );
+  if( x<99 ){
+    pIdx->pTable->nRowLogEst = x = 99;
+  }
+  if( pIdx->pPartIdxWhere!=0 ){ x -= 10;  assert( 10==sqlite3LogEst(2) ); }
+  a[0] = x;
+
+  /* Estimate that a[1] is 10, a[2] is 9, a[3] is 8, a[4] is 7, a[5] is
+  ** 6 and each subsequent value (if any) is 5.  */
+  memcpy(&a[1], aVal, nCopy*sizeof(LogEst));
+  for(i=nCopy+1; i<=pIdx->nKeyCol; i++){
+    a[i] = 23;                    assert( 23==sqlite3LogEst(5) );
+  }
+
+  assert( 0==sqlite3LogEst(1) );
+  if( IsUniqueIndex(pIdx) ) a[pIdx->nKeyCol] = 0;
+}
+
+/*
+** This routine will drop an existing named index.  This routine
+** implements the DROP INDEX statement.
+*/
+SQLITE_PRIVATE void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
+  Index *pIndex;
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  if( db->mallocFailed ){
+    goto exit_drop_index;
+  }
+  assert( pParse->nErr==0 );   /* Never called with prior non-OOM errors */
+  assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 );
+  assert( pName->a[0].fg.isSubquery==0 );
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    goto exit_drop_index;
+  }
+  pIndex = sqlite3FindIndex(db, pName->a[0].zName, pName->a[0].u4.zDatabase);
+  if( pIndex==0 ){
+    if( !ifExists ){
+      sqlite3ErrorMsg(pParse, "no such index: %S", pName->a);
+    }else{
+      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].u4.zDatabase);
+      sqlite3ForceNotReadOnly(pParse);
+    }
+    pParse->checkSchema = 1;
+    goto exit_drop_index;
+  }
+  if( pIndex->idxType!=SQLITE_IDXTYPE_APPDEF ){
+    sqlite3ErrorMsg(pParse, "index associated with UNIQUE "
+      "or PRIMARY KEY constraint cannot be dropped", 0);
+    goto exit_drop_index;
+  }
+  iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  {
+    int code = SQLITE_DROP_INDEX;
+    Table *pTab = pIndex->pTable;
+    const char *zDb = db->aDb[iDb].zDbSName;
+    const char *zTab = SCHEMA_TABLE(iDb);
+    if( sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
+      goto exit_drop_index;
+    }
+    if( !OMIT_TEMPDB && iDb==1 ) code = SQLITE_DROP_TEMP_INDEX;
+    if( sqlite3AuthCheck(pParse, code, pIndex->zName, pTab->zName, zDb) ){
+      goto exit_drop_index;
+    }
+  }
+#endif
+
+  /* Generate code to remove the index and from the schema table */
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3BeginWriteOperation(pParse, 1, iDb);
+    sqlite3NestedParse(pParse,
+       "DELETE FROM %Q." LEGACY_SCHEMA_TABLE " WHERE name=%Q AND type='index'",
+       db->aDb[iDb].zDbSName, pIndex->zName
+    );
+    sqlite3ClearStatTables(pParse, iDb, "idx", pIndex->zName);
+    sqlite3ChangeCookie(pParse, iDb);
+    destroyRootPage(pParse, pIndex->tnum, iDb);
+    sqlite3VdbeAddOp4(v, OP_DropIndex, iDb, 0, 0, pIndex->zName, 0);
+  }
+
+exit_drop_index:
+  sqlite3SrcListDelete(db, pName);
+}
+
+/*
+** pArray is a pointer to an array of objects. Each object in the
+** array is szEntry bytes in size. This routine uses sqlite3DbRealloc()
+** to extend the array so that there is space for a new object at the end.
+**
+** When this function is called, *pnEntry contains the current size of
+** the array (in entries - so the allocation is ((*pnEntry) * szEntry) bytes
+** in total).
+**
+** If the realloc() is successful (i.e. if no OOM condition occurs), the
+** space allocated for the new object is zeroed, *pnEntry updated to
+** reflect the new size of the array and a pointer to the new allocation
+** returned. *pIdx is set to the index of the new array entry in this case.
+**
+** Otherwise, if the realloc() fails, *pIdx is set to -1, *pnEntry remains
+** unchanged and a copy of pArray returned.
+*/
+SQLITE_PRIVATE void *sqlite3ArrayAllocate(
+  sqlite3 *db,      /* Connection to notify of malloc failures */
+  void *pArray,     /* Array of objects.  Might be reallocated */
+  int szEntry,      /* Size of each object in the array */
+  int *pnEntry,     /* Number of objects currently in use */
+  int *pIdx         /* Write the index of a new slot here */
+){
+  char *z;
+  sqlite3_int64 n = *pIdx = *pnEntry;
+  if( (n & (n-1))==0 ){
+    sqlite3_int64 sz = (n==0) ? 1 : 2*n;
+    void *pNew = sqlite3DbRealloc(db, pArray, sz*szEntry);
+    if( pNew==0 ){
+      *pIdx = -1;
+      return pArray;
+    }
+    pArray = pNew;
+  }
+  z = (char*)pArray;
+  memset(&z[n * szEntry], 0, szEntry);
+  ++*pnEntry;
+  return pArray;
+}
+
+/*
+** Append a new element to the given IdList.  Create a new IdList if
+** need be.
+**
+** A new IdList is returned, or NULL if malloc() fails.
+*/
+SQLITE_PRIVATE IdList *sqlite3IdListAppend(Parse *pParse, IdList *pList, Token *pToken){
+  sqlite3 *db = pParse->db;
+  int i;
+  if( pList==0 ){
+    pList = sqlite3DbMallocZero(db, sizeof(IdList) );
+    if( pList==0 ) return 0;
+  }else{
+    IdList *pNew;
+    pNew = sqlite3DbRealloc(db, pList,
+                 sizeof(IdList) + pList->nId*sizeof(pList->a));
+    if( pNew==0 ){
+      sqlite3IdListDelete(db, pList);
+      return 0;
+    }
+    pList = pNew;
+  }
+  i = pList->nId++;
+  pList->a[i].zName = sqlite3NameFromToken(db, pToken);
+  if( IN_RENAME_OBJECT && pList->a[i].zName ){
+    sqlite3RenameTokenMap(pParse, (void*)pList->a[i].zName, pToken);
+  }
+  return pList;
+}
+
+/*
+** Delete an IdList.
+*/
+SQLITE_PRIVATE void sqlite3IdListDelete(sqlite3 *db, IdList *pList){
+  int i;
+  assert( db!=0 );
+  if( pList==0 ) return;
+  for(i=0; i<pList->nId; i++){
+    sqlite3DbFree(db, pList->a[i].zName);
+  }
+  sqlite3DbNNFreeNN(db, pList);
+}
+
+/*
+** Return the index in pList of the identifier named zId.  Return -1
+** if not found.
+*/
+SQLITE_PRIVATE int sqlite3IdListIndex(IdList *pList, const char *zName){
+  int i;
+  assert( pList!=0 );
+  for(i=0; i<pList->nId; i++){
+    if( sqlite3StrICmp(pList->a[i].zName, zName)==0 ) return i;
+  }
+  return -1;
+}
+
+/*
+** Maximum size of a SrcList object.
+** The SrcList object is used to represent the FROM clause of a
+** SELECT statement, and the query planner cannot deal with more
+** than 64 tables in a join.  So any value larger than 64 here
+** is sufficient for most uses.  Smaller values, like say 10, are
+** appropriate for small and memory-limited applications.
+*/
+#ifndef SQLITE_MAX_SRCLIST
+# define SQLITE_MAX_SRCLIST 200
+#endif
+
+/*
+** Expand the space allocated for the given SrcList object by
+** creating nExtra new slots beginning at iStart.  iStart is zero based.
+** New slots are zeroed.
+**
+** For example, suppose a SrcList initially contains two entries: A,B.
+** To append 3 new entries onto the end, do this:
+**
+**    sqlite3SrcListEnlarge(db, pSrclist, 3, 2);
+**
+** After the call above it would contain:  A, B, nil, nil, nil.
+** If the iStart argument had been 1 instead of 2, then the result
+** would have been:  A, nil, nil, nil, B.  To prepend the new slots,
+** the iStart value would be 0.  The result then would
+** be: nil, nil, nil, A, B.
+**
+** If a memory allocation fails or the SrcList becomes too large, leave
+** the original SrcList unchanged, return NULL, and leave an error message
+** in pParse.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListEnlarge(
+  Parse *pParse,     /* Parsing context into which errors are reported */
+  SrcList *pSrc,     /* The SrcList to be enlarged */
+  int nExtra,        /* Number of new slots to add to pSrc->a[] */
+  int iStart         /* Index in pSrc->a[] of first new slot */
+){
+  int i;
+
+  /* Sanity checking on calling parameters */
+  assert( iStart>=0 );
+  assert( nExtra>=1 );
+  assert( pSrc!=0 );
+  assert( iStart<=pSrc->nSrc );
+
+  /* Allocate additional space if needed */
+  if( (u32)pSrc->nSrc+nExtra>pSrc->nAlloc ){
+    SrcList *pNew;
+    sqlite3_int64 nAlloc = 2*(sqlite3_int64)pSrc->nSrc+nExtra;
+    sqlite3 *db = pParse->db;
+
+    if( pSrc->nSrc+nExtra>=SQLITE_MAX_SRCLIST ){
+      sqlite3ErrorMsg(pParse, "too many FROM clause terms, max: %d",
+                      SQLITE_MAX_SRCLIST);
+      return 0;
+    }
+    if( nAlloc>SQLITE_MAX_SRCLIST ) nAlloc = SQLITE_MAX_SRCLIST;
+    pNew = sqlite3DbRealloc(db, pSrc,
+               sizeof(*pSrc) + (nAlloc-1)*sizeof(pSrc->a[0]) );
+    if( pNew==0 ){
+      assert( db->mallocFailed );
+      return 0;
+    }
+    pSrc = pNew;
+    pSrc->nAlloc = nAlloc;
+  }
+
+  /* Move existing slots that come after the newly inserted slots
+  ** out of the way */
+  for(i=pSrc->nSrc-1; i>=iStart; i--){
+    pSrc->a[i+nExtra] = pSrc->a[i];
+  }
+  pSrc->nSrc += nExtra;
+
+  /* Zero the newly allocated slots */
+  memset(&pSrc->a[iStart], 0, sizeof(pSrc->a[0])*nExtra);
+  for(i=iStart; i<iStart+nExtra; i++){
+    pSrc->a[i].iCursor = -1;
+  }
+
+  /* Return a pointer to the enlarged SrcList */
+  return pSrc;
+}
+
+
+/*
+** Append a new table name to the given SrcList.  Create a new SrcList if
+** need be.  A new entry is created in the SrcList even if pTable is NULL.
+**
+** A SrcList is returned, or NULL if there is an OOM error or if the
+** SrcList grows to large.  The returned
+** SrcList might be the same as the SrcList that was input or it might be
+** a new one.  If an OOM error does occurs, then the prior value of pList
+** that is input to this routine is automatically freed.
+**
+** If pDatabase is not null, it means that the table has an optional
+** database name prefix.  Like this:  "database.table".  The pDatabase
+** points to the table name and the pTable points to the database name.
+** The SrcList.a[].zName field is filled with the table name which might
+** come from pTable (if pDatabase is NULL) or from pDatabase.
+** SrcList.a[].zDatabase is filled with the database name from pTable,
+** or with NULL if no database is specified.
+**
+** In other words, if call like this:
+**
+**         sqlite3SrcListAppend(D,A,B,0);
+**
+** Then B is a table name and the database name is unspecified.  If called
+** like this:
+**
+**         sqlite3SrcListAppend(D,A,B,C);
+**
+** Then C is the table name and B is the database name.  If C is defined
+** then so is B.  In other words, we never have a case where:
+**
+**         sqlite3SrcListAppend(D,A,0,C);
+**
+** Both pTable and pDatabase are assumed to be quoted.  They are dequoted
+** before being added to the SrcList.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppend(
+  Parse *pParse,      /* Parsing context, in which errors are reported */
+  SrcList *pList,     /* Append to this SrcList. NULL creates a new SrcList */
+  Token *pTable,      /* Table to append */
+  Token *pDatabase    /* Database of the table */
+){
+  SrcItem *pItem;
+  sqlite3 *db;
+  assert( pDatabase==0 || pTable!=0 );  /* Cannot have C without B */
+  assert( pParse!=0 );
+  assert( pParse->db!=0 );
+  db = pParse->db;
+  if( pList==0 ){
+    pList = sqlite3DbMallocRawNN(pParse->db, sizeof(SrcList) );
+    if( pList==0 ) return 0;
+    pList->nAlloc = 1;
+    pList->nSrc = 1;
+    memset(&pList->a[0], 0, sizeof(pList->a[0]));
+    pList->a[0].iCursor = -1;
+  }else{
+    SrcList *pNew = sqlite3SrcListEnlarge(pParse, pList, 1, pList->nSrc);
+    if( pNew==0 ){
+      sqlite3SrcListDelete(db, pList);
+      return 0;
+    }else{
+      pList = pNew;
+    }
+  }
+  pItem = &pList->a[pList->nSrc-1];
+  if( pDatabase && pDatabase->z==0 ){
+    pDatabase = 0;
+  }
+  assert( pItem->fg.fixedSchema==0 );
+  assert( pItem->fg.isSubquery==0 );
+  if( pDatabase ){
+    pItem->zName = sqlite3NameFromToken(db, pDatabase);
+    pItem->u4.zDatabase = sqlite3NameFromToken(db, pTable);
+  }else{
+    pItem->zName = sqlite3NameFromToken(db, pTable);
+    pItem->u4.zDatabase = 0;
+  }
+  return pList;
+}
+
+/*
+** Assign VdbeCursor index numbers to all tables in a SrcList
+*/
+SQLITE_PRIVATE void sqlite3SrcListAssignCursors(Parse *pParse, SrcList *pList){
+  int i;
+  SrcItem *pItem;
+  assert( pList || pParse->db->mallocFailed );
+  if( ALWAYS(pList) ){
+    for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
+      if( pItem->iCursor>=0 ) continue;
+      pItem->iCursor = pParse->nTab++;
+      if( pItem->fg.isSubquery ){
+        assert( pItem->u4.pSubq!=0 );
+        assert( pItem->u4.pSubq->pSelect!=0 );
+        assert( pItem->u4.pSubq->pSelect->pSrc!=0 );
+        sqlite3SrcListAssignCursors(pParse, pItem->u4.pSubq->pSelect->pSrc);
+      }
+    }
+  }
+}
+
+/*
+** Delete a Subquery object and its substructure.
+*/
+SQLITE_PRIVATE void sqlite3SubqueryDelete(sqlite3 *db, Subquery *pSubq){
+  assert( pSubq!=0 && pSubq->pSelect!=0 );
+  sqlite3SelectDelete(db, pSubq->pSelect);
+  sqlite3DbFree(db, pSubq);
+}
+
+/*
+** Remove a Subquery from a SrcItem.  Return the associated Select object.
+** The returned Select becomes the responsibility of the caller.
+*/
+SQLITE_PRIVATE Select *sqlite3SubqueryDetach(sqlite3 *db, SrcItem *pItem){
+  Select *pSel;
+  assert( pItem!=0 );
+  assert( pItem->fg.isSubquery );
+  pSel = pItem->u4.pSubq->pSelect;
+  sqlite3DbFree(db, pItem->u4.pSubq);
+  pItem->u4.pSubq = 0;
+  pItem->fg.isSubquery = 0;
+  return pSel;
+}
+
+/*
+** Delete an entire SrcList including all its substructure.
+*/
+SQLITE_PRIVATE void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
+  int i;
+  SrcItem *pItem;
+  assert( db!=0 );
+  if( pList==0 ) return;
+  for(pItem=pList->a, i=0; i<pList->nSrc; i++, pItem++){
+
+    /* Check invariants on SrcItem */
+    assert( !pItem->fg.isIndexedBy || !pItem->fg.isTabFunc );
+    assert( !pItem->fg.isCte || !pItem->fg.isIndexedBy );
+    assert( !pItem->fg.fixedSchema || !pItem->fg.isSubquery );
+    assert( !pItem->fg.isSubquery || (pItem->u4.pSubq!=0 &&
+                                      pItem->u4.pSubq->pSelect!=0) );
+
+    if( pItem->zName ) sqlite3DbNNFreeNN(db, pItem->zName);
+    if( pItem->zAlias ) sqlite3DbNNFreeNN(db, pItem->zAlias);
+    if( pItem->fg.isSubquery ){
+      sqlite3SubqueryDelete(db, pItem->u4.pSubq);
+    }else if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+      sqlite3DbNNFreeNN(db, pItem->u4.zDatabase);
+    }
+    if( pItem->fg.isIndexedBy ) sqlite3DbFree(db, pItem->u1.zIndexedBy);
+    if( pItem->fg.isTabFunc ) sqlite3ExprListDelete(db, pItem->u1.pFuncArg);
+    sqlite3DeleteTable(db, pItem->pSTab);
+    if( pItem->fg.isUsing ){
+      sqlite3IdListDelete(db, pItem->u3.pUsing);
+    }else if( pItem->u3.pOn ){
+      sqlite3ExprDelete(db, pItem->u3.pOn);
+    }
+  }
+  sqlite3DbNNFreeNN(db, pList);
+}
+
+/*
+** Attach a Subquery object to pItem->uv.pSubq.  Set the
+** pSelect value but leave all the other values initialized
+** to zero.
+**
+** A copy of the Select object is made if dupSelect is true, and the
+** SrcItem takes responsibility for deleting the copy.  If dupSelect is
+** false, ownership of the Select passes to the SrcItem.  Either way,
+** the SrcItem will take responsibility for deleting the Select.
+**
+** When dupSelect is zero, that means the Select might get deleted right
+** away if there is an OOM error.  Beware.
+**
+** Return non-zero on success.  Return zero on an OOM error.
+*/
+SQLITE_PRIVATE int sqlite3SrcItemAttachSubquery(
+  Parse *pParse,     /* Parsing context */
+  SrcItem *pItem,    /* Item to which the subquery is to be attached */
+  Select *pSelect,   /* The subquery SELECT.  Must be non-NULL */
+  int dupSelect      /* If true, attach a copy of pSelect, not pSelect itself.*/
+){
+  Subquery *p;
+  assert( pSelect!=0 );
+  assert( pItem->fg.isSubquery==0 );
+  if( pItem->fg.fixedSchema ){
+    pItem->u4.pSchema = 0;
+    pItem->fg.fixedSchema = 0;
+  }else if( pItem->u4.zDatabase!=0 ){
+    sqlite3DbFree(pParse->db, pItem->u4.zDatabase);
+    pItem->u4.zDatabase = 0;
+  }
+  if( dupSelect ){
+    pSelect = sqlite3SelectDup(pParse->db, pSelect, 0);
+    if( pSelect==0 ) return 0;
+  }
+  p = pItem->u4.pSubq = sqlite3DbMallocRawNN(pParse->db, sizeof(Subquery));
+  if( p==0 ){
+    sqlite3SelectDelete(pParse->db, pSelect);
+    return 0;
+  }
+  pItem->fg.isSubquery = 1;
+  p->pSelect = pSelect;
+  assert( offsetof(Subquery, pSelect)==0 );
+  memset(((char*)p)+sizeof(p->pSelect), 0, sizeof(*p)-sizeof(p->pSelect));
+  return 1;
+}
+
+
+/*
+** This routine is called by the parser to add a new term to the
+** end of a growing FROM clause.  The "p" parameter is the part of
+** the FROM clause that has already been constructed.  "p" is NULL
+** if this is the first term of the FROM clause.  pTable and pDatabase
+** are the name of the table and database named in the FROM clause term.
+** pDatabase is NULL if the database name qualifier is missing - the
+** usual case.  If the term has an alias, then pAlias points to the
+** alias token.  If the term is a subquery, then pSubquery is the
+** SELECT statement that the subquery encodes.  The pTable and
+** pDatabase parameters are NULL for subqueries.  The pOn and pUsing
+** parameters are the content of the ON and USING clauses.
+**
+** Return a new SrcList which encodes is the FROM with the new
+** term added.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendFromTerm(
+  Parse *pParse,          /* Parsing context */
+  SrcList *p,             /* The left part of the FROM clause already seen */
+  Token *pTable,          /* Name of the table to add to the FROM clause */
+  Token *pDatabase,       /* Name of the database containing pTable */
+  Token *pAlias,          /* The right-hand side of the AS subexpression */
+  Select *pSubquery,      /* A subquery used in place of a table name */
+  OnOrUsing *pOnUsing     /* Either the ON clause or the USING clause */
+){
+  SrcItem *pItem;
+  sqlite3 *db = pParse->db;
+  if( !p && pOnUsing!=0 && (pOnUsing->pOn || pOnUsing->pUsing) ){
+    sqlite3ErrorMsg(pParse, "a JOIN clause is required before %s",
+      (pOnUsing->pOn ? "ON" : "USING")
+    );
+    goto append_from_error;
+  }
+  p = sqlite3SrcListAppend(pParse, p, pTable, pDatabase);
+  if( p==0 ){
+    goto append_from_error;
+  }
+  assert( p->nSrc>0 );
+  pItem = &p->a[p->nSrc-1];
+  assert( (pTable==0)==(pDatabase==0) );
+  assert( pItem->zName==0 || pDatabase!=0 );
+  if( IN_RENAME_OBJECT && pItem->zName ){
+    Token *pToken = (ALWAYS(pDatabase) && pDatabase->z) ? pDatabase : pTable;
+    sqlite3RenameTokenMap(pParse, pItem->zName, pToken);
+  }
+  assert( pAlias!=0 );
+  if( pAlias->n ){
+    pItem->zAlias = sqlite3NameFromToken(db, pAlias);
+  }
+  assert( pSubquery==0 || pDatabase==0 );
+  if( pSubquery ){
+    if( sqlite3SrcItemAttachSubquery(pParse, pItem, pSubquery, 0) ){
+      if( pSubquery->selFlags & SF_NestedFrom ){
+        pItem->fg.isNestedFrom = 1;
+      }
+    }
+  }
+  assert( pOnUsing==0 || pOnUsing->pOn==0 || pOnUsing->pUsing==0 );
+  assert( pItem->fg.isUsing==0 );
+  if( pOnUsing==0 ){
+    pItem->u3.pOn = 0;
+  }else if( pOnUsing->pUsing ){
+    pItem->fg.isUsing = 1;
+    pItem->u3.pUsing = pOnUsing->pUsing;
+  }else{
+    pItem->u3.pOn = pOnUsing->pOn;
+  }
+  return p;
+
+append_from_error:
+  assert( p==0 );
+  sqlite3ClearOnOrUsing(db, pOnUsing);
+  sqlite3SelectDelete(db, pSubquery);
+  return 0;
+}
+
+/*
+** Add an INDEXED BY or NOT INDEXED clause to the most recently added
+** element of the source-list passed as the second argument.
+*/
+SQLITE_PRIVATE void sqlite3SrcListIndexedBy(Parse *pParse, SrcList *p, Token *pIndexedBy){
+  assert( pIndexedBy!=0 );
+  if( p && pIndexedBy->n>0 ){
+    SrcItem *pItem;
+    assert( p->nSrc>0 );
+    pItem = &p->a[p->nSrc-1];
+    assert( pItem->fg.notIndexed==0 );
+    assert( pItem->fg.isIndexedBy==0 );
+    assert( pItem->fg.isTabFunc==0 );
+    if( pIndexedBy->n==1 && !pIndexedBy->z ){
+      /* A "NOT INDEXED" clause was supplied. See parse.y
+      ** construct "indexed_opt" for details. */
+      pItem->fg.notIndexed = 1;
+    }else{
+      pItem->u1.zIndexedBy = sqlite3NameFromToken(pParse->db, pIndexedBy);
+      pItem->fg.isIndexedBy = 1;
+      assert( pItem->fg.isCte==0 );  /* No collision on union u2 */
+    }
+  }
+}
+
+/*
+** Append the contents of SrcList p2 to SrcList p1 and return the resulting
+** SrcList. Or, if an error occurs, return NULL. In all cases, p1 and p2
+** are deleted by this function.
+*/
+SQLITE_PRIVATE SrcList *sqlite3SrcListAppendList(Parse *pParse, SrcList *p1, SrcList *p2){
+  assert( p1 && p1->nSrc==1 );
+  if( p2 ){
+    SrcList *pNew = sqlite3SrcListEnlarge(pParse, p1, p2->nSrc, 1);
+    if( pNew==0 ){
+      sqlite3SrcListDelete(pParse->db, p2);
+    }else{
+      p1 = pNew;
+      memcpy(&p1->a[1], p2->a, p2->nSrc*sizeof(SrcItem));
+      sqlite3DbFree(pParse->db, p2);
+      p1->a[0].fg.jointype |= (JT_LTORJ & p1->a[1].fg.jointype);
+    }
+  }
+  return p1;
+}
+
+/*
+** Add the list of function arguments to the SrcList entry for a
+** table-valued-function.
+*/
+SQLITE_PRIVATE void sqlite3SrcListFuncArgs(Parse *pParse, SrcList *p, ExprList *pList){
+  if( p ){
+    SrcItem *pItem = &p->a[p->nSrc-1];
+    assert( pItem->fg.notIndexed==0 );
+    assert( pItem->fg.isIndexedBy==0 );
+    assert( pItem->fg.isTabFunc==0 );
+    pItem->u1.pFuncArg = pList;
+    pItem->fg.isTabFunc = 1;
+  }else{
+    sqlite3ExprListDelete(pParse->db, pList);
+  }
+}
+
+/*
+** When building up a FROM clause in the parser, the join operator
+** is initially attached to the left operand.  But the code generator
+** expects the join operator to be on the right operand.  This routine
+** Shifts all join operators from left to right for an entire FROM
+** clause.
+**
+** Example: Suppose the join is like this:
+**
+**           A natural cross join B
+**
+** The operator is "natural cross join".  The A and B operands are stored
+** in p->a[0] and p->a[1], respectively.  The parser initially stores the
+** operator with A.  This routine shifts that operator over to B.
+**
+** Additional changes:
+**
+**   *   All tables to the left of the right-most RIGHT JOIN are tagged with
+**       JT_LTORJ (mnemonic: Left Table Of Right Join) so that the
+**       code generator can easily tell that the table is part of
+**       the left operand of at least one RIGHT JOIN.
+*/
+SQLITE_PRIVATE void sqlite3SrcListShiftJoinType(Parse *pParse, SrcList *p){
+  (void)pParse;
+  if( p && p->nSrc>1 ){
+    int i = p->nSrc-1;
+    u8 allFlags = 0;
+    do{
+      allFlags |= p->a[i].fg.jointype = p->a[i-1].fg.jointype;
+    }while( (--i)>0 );
+    p->a[0].fg.jointype = 0;
+
+    /* All terms to the left of a RIGHT JOIN should be tagged with the
+    ** JT_LTORJ flags */
+    if( allFlags & JT_RIGHT ){
+      for(i=p->nSrc-1; ALWAYS(i>0) && (p->a[i].fg.jointype&JT_RIGHT)==0; i--){}
+      i--;
+      assert( i>=0 );
+      do{
+        p->a[i].fg.jointype |= JT_LTORJ;
+      }while( (--i)>=0 );
+    }
+  }
+}
+
+/*
+** Generate VDBE code for a BEGIN statement.
+*/
+SQLITE_PRIVATE void sqlite3BeginTransaction(Parse *pParse, int type){
+  sqlite3 *db;
+  Vdbe *v;
+  int i;
+
+  assert( pParse!=0 );
+  db = pParse->db;
+  assert( db!=0 );
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION, "BEGIN", 0, 0) ){
+    return;
+  }
+  v = sqlite3GetVdbe(pParse);
+  if( !v ) return;
+  if( type!=TK_DEFERRED ){
+    for(i=0; i<db->nDb; i++){
+      int eTxnType;
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt && sqlite3BtreeIsReadonly(pBt) ){
+        eTxnType = 0;  /* Read txn */
+      }else if( type==TK_EXCLUSIVE ){
+        eTxnType = 2;  /* Exclusive txn */
+      }else{
+        eTxnType = 1;  /* Write txn */
+      }
+      sqlite3VdbeAddOp2(v, OP_Transaction, i, eTxnType);
+      sqlite3VdbeUsesBtree(v, i);
+    }
+  }
+  sqlite3VdbeAddOp0(v, OP_AutoCommit);
+}
+
+/*
+** Generate VDBE code for a COMMIT or ROLLBACK statement.
+** Code for ROLLBACK is generated if eType==TK_ROLLBACK.  Otherwise
+** code is generated for a COMMIT.
+*/
+SQLITE_PRIVATE void sqlite3EndTransaction(Parse *pParse, int eType){
+  Vdbe *v;
+  int isRollback;
+
+  assert( pParse!=0 );
+  assert( pParse->db!=0 );
+  assert( eType==TK_COMMIT || eType==TK_END || eType==TK_ROLLBACK );
+  isRollback = eType==TK_ROLLBACK;
+  if( sqlite3AuthCheck(pParse, SQLITE_TRANSACTION,
+       isRollback ? "ROLLBACK" : "COMMIT", 0, 0) ){
+    return;
+  }
+  v = sqlite3GetVdbe(pParse);
+  if( v ){
+    sqlite3VdbeAddOp2(v, OP_AutoCommit, 1, isRollback);
+  }
+}
+
+/*
+** This function is called by the parser when it parses a command to create,
+** release or rollback an SQL savepoint.
+*/
+SQLITE_PRIVATE void sqlite3Savepoint(Parse *pParse, int op, Token *pName){
+  char *zName = sqlite3NameFromToken(pParse->db, pName);
+  if( zName ){
+    Vdbe *v = sqlite3GetVdbe(pParse);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    static const char * const az[] = { "BEGIN", "RELEASE", "ROLLBACK" };
+    assert( !SAVEPOINT_BEGIN && SAVEPOINT_RELEASE==1 && SAVEPOINT_ROLLBACK==2 );
+#endif
+    if( !v || sqlite3AuthCheck(pParse, SQLITE_SAVEPOINT, az[op], zName, 0) ){
+      sqlite3DbFree(pParse->db, zName);
+      return;
+    }
+    sqlite3VdbeAddOp4(v, OP_Savepoint, op, 0, 0, zName, P4_DYNAMIC);
+  }
+}
+
+/*
+** Make sure the TEMP database is open and available for use.  Return
+** the number of errors.  Leave any error messages in the pParse structure.
+*/
+SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  if( db->aDb[1].pBt==0 && !pParse->explain ){
+    int rc;
+    Btree *pBt;
+    static const int flags =
+          SQLITE_OPEN_READWRITE |
+          SQLITE_OPEN_CREATE |
+          SQLITE_OPEN_EXCLUSIVE |
+          SQLITE_OPEN_DELETEONCLOSE |
+          SQLITE_OPEN_TEMP_DB;
+
+    rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pBt, 0, flags);
+    if( rc!=SQLITE_OK ){
+      sqlite3ErrorMsg(pParse, "unable to open a temporary database "
+        "file for storing temporary tables");
+      pParse->rc = rc;
+      return 1;
+    }
+    db->aDb[1].pBt = pBt;
+    assert( db->aDb[1].pSchema );
+    if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize, 0, 0) ){
+      sqlite3OomFault(db);
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Record the fact that the schema cookie will need to be verified
+** for database iDb.  The code to actually verify the schema cookie
+** will occur at the end of the top-level VDBE and will be generated
+** later, by sqlite3FinishCoding().
+*/
+static void sqlite3CodeVerifySchemaAtToplevel(Parse *pToplevel, int iDb){
+  assert( iDb>=0 && iDb<pToplevel->db->nDb );
+  assert( pToplevel->db->aDb[iDb].pBt!=0 || iDb==1 );
+  assert( iDb<SQLITE_MAX_DB );
+  assert( sqlite3SchemaMutexHeld(pToplevel->db, iDb, 0) );
+  if( DbMaskTest(pToplevel->cookieMask, iDb)==0 ){
+    DbMaskSet(pToplevel->cookieMask, iDb);
+    if( !OMIT_TEMPDB && iDb==1 ){
+      sqlite3OpenTempDatabase(pToplevel);
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
+  sqlite3CodeVerifySchemaAtToplevel(sqlite3ParseToplevel(pParse), iDb);
+}
+
+
+/*
+** If argument zDb is NULL, then call sqlite3CodeVerifySchema() for each
+** attached database. Otherwise, invoke it for the database named zDb only.
+*/
+SQLITE_PRIVATE void sqlite3CodeVerifyNamedSchema(Parse *pParse, const char *zDb){
+  sqlite3 *db = pParse->db;
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Db *pDb = &db->aDb[i];
+    if( pDb->pBt && (!zDb || 0==sqlite3StrICmp(zDb, pDb->zDbSName)) ){
+      sqlite3CodeVerifySchema(pParse, i);
+    }
+  }
+}
+
+/*
+** Generate VDBE code that prepares for doing an operation that
+** might change the database.
+**
+** This routine starts a new transaction if we are not already within
+** a transaction.  If we are already within a transaction, then a checkpoint
+** is set if the setStatement parameter is true.  A checkpoint should
+** be set for operations that might fail (due to a constraint) part of
+** the way through and which will need to undo some writes without having to
+** rollback the whole transaction.  For operations where all constraints
+** can be checked before any changes are made to the database, it is never
+** necessary to undo a write and the checkpoint should not be set.
+*/
+SQLITE_PRIVATE void sqlite3BeginWriteOperation(Parse *pParse, int setStatement, int iDb){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  sqlite3CodeVerifySchemaAtToplevel(pToplevel, iDb);
+  DbMaskSet(pToplevel->writeMask, iDb);
+  pToplevel->isMultiWrite |= setStatement;
+}
+
+/*
+** Indicate that the statement currently under construction might write
+** more than one entry (example: deleting one row then inserting another,
+** inserting multiple rows in a table, or inserting a row and index entries.)
+** If an abort occurs after some of these writes have completed, then it will
+** be necessary to undo the completed writes.
+*/
+SQLITE_PRIVATE void sqlite3MultiWrite(Parse *pParse){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  pToplevel->isMultiWrite = 1;
+}
+
+/*
+** The code generator calls this routine if is discovers that it is
+** possible to abort a statement prior to completion.  In order to
+** perform this abort without corrupting the database, we need to make
+** sure that the statement is protected by a statement transaction.
+**
+** Technically, we only need to set the mayAbort flag if the
+** isMultiWrite flag was previously set.  There is a time dependency
+** such that the abort must occur after the multiwrite.  This makes
+** some statements involving the REPLACE conflict resolution algorithm
+** go a little faster.  But taking advantage of this time dependency
+** makes it more difficult to prove that the code is correct (in
+** particular, it prevents us from writing an effective
+** implementation of sqlite3AssertMayAbort()) and so we have chosen
+** to take the safe route and skip the optimization.
+*/
+SQLITE_PRIVATE void sqlite3MayAbort(Parse *pParse){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  pToplevel->mayAbort = 1;
+}
+
+/*
+** Code an OP_Halt that causes the vdbe to return an SQLITE_CONSTRAINT
+** error. The onError parameter determines which (if any) of the statement
+** and/or current transaction is rolled back.
+*/
+SQLITE_PRIVATE void sqlite3HaltConstraint(
+  Parse *pParse,    /* Parsing context */
+  int errCode,      /* extended error code */
+  int onError,      /* Constraint type */
+  char *p4,         /* Error message */
+  i8 p4type,        /* P4_STATIC or P4_TRANSIENT */
+  u8 p5Errmsg       /* P5_ErrMsg type */
+){
+  Vdbe *v;
+  assert( pParse->pVdbe!=0 );
+  v = sqlite3GetVdbe(pParse);
+  assert( (errCode&0xff)==SQLITE_CONSTRAINT || pParse->nested );
+  if( onError==OE_Abort ){
+    sqlite3MayAbort(pParse);
+  }
+  sqlite3VdbeAddOp4(v, OP_Halt, errCode, onError, 0, p4, p4type);
+  sqlite3VdbeChangeP5(v, p5Errmsg);
+}
+
+/*
+** Code an OP_Halt due to UNIQUE or PRIMARY KEY constraint violation.
+*/
+SQLITE_PRIVATE void sqlite3UniqueConstraint(
+  Parse *pParse,    /* Parsing context */
+  int onError,      /* Constraint type */
+  Index *pIdx       /* The index that triggers the constraint */
+){
+  char *zErr;
+  int j;
+  StrAccum errMsg;
+  Table *pTab = pIdx->pTable;
+
+  sqlite3StrAccumInit(&errMsg, pParse->db, 0, 0,
+                      pParse->db->aLimit[SQLITE_LIMIT_LENGTH]);
+  if( pIdx->aColExpr ){
+    sqlite3_str_appendf(&errMsg, "index '%q'", pIdx->zName);
+  }else{
+    for(j=0; j<pIdx->nKeyCol; j++){
+      char *zCol;
+      assert( pIdx->aiColumn[j]>=0 );
+      zCol = pTab->aCol[pIdx->aiColumn[j]].zCnName;
+      if( j ) sqlite3_str_append(&errMsg, ", ", 2);
+      sqlite3_str_appendall(&errMsg, pTab->zName);
+      sqlite3_str_append(&errMsg, ".", 1);
+      sqlite3_str_appendall(&errMsg, zCol);
+    }
+  }
+  zErr = sqlite3StrAccumFinish(&errMsg);
+  sqlite3HaltConstraint(pParse,
+    IsPrimaryKeyIndex(pIdx) ? SQLITE_CONSTRAINT_PRIMARYKEY
+                            : SQLITE_CONSTRAINT_UNIQUE,
+    onError, zErr, P4_DYNAMIC, P5_ConstraintUnique);
+}
+
+
+/*
+** Code an OP_Halt due to non-unique rowid.
+*/
+SQLITE_PRIVATE void sqlite3RowidConstraint(
+  Parse *pParse,    /* Parsing context */
+  int onError,      /* Conflict resolution algorithm */
+  Table *pTab       /* The table with the non-unique rowid */
+){
+  char *zMsg;
+  int rc;
+  if( pTab->iPKey>=0 ){
+    zMsg = sqlite3MPrintf(pParse->db, "%s.%s", pTab->zName,
+                          pTab->aCol[pTab->iPKey].zCnName);
+    rc = SQLITE_CONSTRAINT_PRIMARYKEY;
+  }else{
+    zMsg = sqlite3MPrintf(pParse->db, "%s.rowid", pTab->zName);
+    rc = SQLITE_CONSTRAINT_ROWID;
+  }
+  sqlite3HaltConstraint(pParse, rc, onError, zMsg, P4_DYNAMIC,
+                        P5_ConstraintUnique);
+}
+
+/*
+** Check to see if pIndex uses the collating sequence pColl.  Return
+** true if it does and false if it does not.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+static int collationMatch(const char *zColl, Index *pIndex){
+  int i;
+  assert( zColl!=0 );
+  for(i=0; i<pIndex->nColumn; i++){
+    const char *z = pIndex->azColl[i];
+    assert( z!=0 || pIndex->aiColumn[i]<0 );
+    if( pIndex->aiColumn[i]>=0 && 0==sqlite3StrICmp(z, zColl) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+#endif
+
+/*
+** Recompute all indices of pTab that use the collating sequence pColl.
+** If pColl==0 then recompute all indices of pTab.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+static void reindexTable(Parse *pParse, Table *pTab, char const *zColl){
+  if( !IsVirtual(pTab) ){
+    Index *pIndex;              /* An index associated with pTab */
+
+    for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
+      if( zColl==0 || collationMatch(zColl, pIndex) ){
+        int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+        sqlite3BeginWriteOperation(pParse, 0, iDb);
+        sqlite3RefillIndex(pParse, pIndex, -1);
+      }
+    }
+  }
+}
+#endif
+
+/*
+** Recompute all indices of all tables in all databases where the
+** indices use the collating sequence pColl.  If pColl==0 then recompute
+** all indices everywhere.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+static void reindexDatabases(Parse *pParse, char const *zColl){
+  Db *pDb;                    /* A single database */
+  int iDb;                    /* The database index number */
+  sqlite3 *db = pParse->db;   /* The database connection */
+  HashElem *k;                /* For looping over tables in pDb */
+  Table *pTab;                /* A table in the database */
+
+  assert( sqlite3BtreeHoldsAllMutexes(db) );  /* Needed for schema access */
+  for(iDb=0, pDb=db->aDb; iDb<db->nDb; iDb++, pDb++){
+    assert( pDb!=0 );
+    for(k=sqliteHashFirst(&pDb->pSchema->tblHash);  k; k=sqliteHashNext(k)){
+      pTab = (Table*)sqliteHashData(k);
+      reindexTable(pParse, pTab, zColl);
+    }
+  }
+}
+#endif
+
+/*
+** Generate code for the REINDEX command.
+**
+**        REINDEX                            -- 1
+**        REINDEX  <collation>               -- 2
+**        REINDEX  ?<database>.?<tablename>  -- 3
+**        REINDEX  ?<database>.?<indexname>  -- 4
+**
+** Form 1 causes all indices in all attached databases to be rebuilt.
+** Form 2 rebuilds all indices in all databases that use the named
+** collating function.  Forms 3 and 4 rebuild the named index or all
+** indices associated with the named table.
+*/
+#ifndef SQLITE_OMIT_REINDEX
+SQLITE_PRIVATE void sqlite3Reindex(Parse *pParse, Token *pName1, Token *pName2){
+  CollSeq *pColl;             /* Collating sequence to be reindexed, or NULL */
+  char *z;                    /* Name of a table or index */
+  const char *zDb;            /* Name of the database */
+  Table *pTab;                /* A table in the database */
+  Index *pIndex;              /* An index associated with pTab */
+  int iDb;                    /* The database index number */
+  sqlite3 *db = pParse->db;   /* The database connection */
+  Token *pObjName;            /* Name of the table or index to be reindexed */
+
+  /* Read the database schema. If an error occurs, leave an error message
+  ** and code in pParse and return NULL. */
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    return;
+  }
+
+  if( pName1==0 ){
+    reindexDatabases(pParse, 0);
+    return;
+  }else if( NEVER(pName2==0) || pName2->z==0 ){
+    char *zColl;
+    assert( pName1->z );
+    zColl = sqlite3NameFromToken(pParse->db, pName1);
+    if( !zColl ) return;
+    pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);
+    if( pColl ){
+      reindexDatabases(pParse, zColl);
+      sqlite3DbFree(db, zColl);
+      return;
+    }
+    sqlite3DbFree(db, zColl);
+  }
+  iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pObjName);
+  if( iDb<0 ) return;
+  z = sqlite3NameFromToken(db, pObjName);
+  if( z==0 ) return;
+  zDb = pName2->n ? db->aDb[iDb].zDbSName : 0;
+  pTab = sqlite3FindTable(db, z, zDb);
+  if( pTab ){
+    reindexTable(pParse, pTab, 0);
+    sqlite3DbFree(db, z);
+    return;
+  }
+  pIndex = sqlite3FindIndex(db, z, zDb);
+  sqlite3DbFree(db, z);
+  if( pIndex ){
+    iDb = sqlite3SchemaToIndex(db, pIndex->pTable->pSchema);
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    sqlite3RefillIndex(pParse, pIndex, -1);
+    return;
+  }
+  sqlite3ErrorMsg(pParse, "unable to identify the object to be reindexed");
+}
+#endif
+
+/*
+** Return a KeyInfo structure that is appropriate for the given Index.
+**
+** The caller should invoke sqlite3KeyInfoUnref() on the returned object
+** when it has finished using it.
+*/
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoOfIndex(Parse *pParse, Index *pIdx){
+  int i;
+  int nCol = pIdx->nColumn;
+  int nKey = pIdx->nKeyCol;
+  KeyInfo *pKey;
+  if( pParse->nErr ) return 0;
+  if( pIdx->uniqNotNull ){
+    pKey = sqlite3KeyInfoAlloc(pParse->db, nKey, nCol-nKey);
+  }else{
+    pKey = sqlite3KeyInfoAlloc(pParse->db, nCol, 0);
+  }
+  if( pKey ){
+    assert( sqlite3KeyInfoIsWriteable(pKey) );
+    for(i=0; i<nCol; i++){
+      const char *zColl = pIdx->azColl[i];
+      pKey->aColl[i] = zColl==sqlite3StrBINARY ? 0 :
+                        sqlite3LocateCollSeq(pParse, zColl);
+      pKey->aSortFlags[i] = pIdx->aSortOrder[i];
+      assert( 0==(pKey->aSortFlags[i] & KEYINFO_ORDER_BIGNULL) );
+    }
+    if( pParse->nErr ){
+      assert( pParse->rc==SQLITE_ERROR_MISSING_COLLSEQ );
+      if( pIdx->bNoQuery==0 ){
+        /* Deactivate the index because it contains an unknown collating
+        ** sequence.  The only way to reactive the index is to reload the
+        ** schema.  Adding the missing collating sequence later does not
+        ** reactive the index.  The application had the chance to register
+        ** the missing index using the collation-needed callback.  For
+        ** simplicity, SQLite will not give the application a second chance.
+        */
+        pIdx->bNoQuery = 1;
+        pParse->rc = SQLITE_ERROR_RETRY;
+      }
+      sqlite3KeyInfoUnref(pKey);
+      pKey = 0;
+    }
+  }
+  return pKey;
+}
+
+#ifndef SQLITE_OMIT_CTE
+/*
+** Create a new CTE object
+*/
+SQLITE_PRIVATE Cte *sqlite3CteNew(
+  Parse *pParse,          /* Parsing context */
+  Token *pName,           /* Name of the common-table */
+  ExprList *pArglist,     /* Optional column name list for the table */
+  Select *pQuery,         /* Query used to initialize the table */
+  u8 eM10d                /* The MATERIALIZED flag */
+){
+  Cte *pNew;
+  sqlite3 *db = pParse->db;
+
+  pNew = sqlite3DbMallocZero(db, sizeof(*pNew));
+  assert( pNew!=0 || db->mallocFailed );
+
+  if( db->mallocFailed ){
+    sqlite3ExprListDelete(db, pArglist);
+    sqlite3SelectDelete(db, pQuery);
+  }else{
+    pNew->pSelect = pQuery;
+    pNew->pCols = pArglist;
+    pNew->zName = sqlite3NameFromToken(pParse->db, pName);
+    pNew->eM10d = eM10d;
+  }
+  return pNew;
+}
+
+/*
+** Clear information from a Cte object, but do not deallocate storage
+** for the object itself.
+*/
+static void cteClear(sqlite3 *db, Cte *pCte){
+  assert( pCte!=0 );
+  sqlite3ExprListDelete(db, pCte->pCols);
+  sqlite3SelectDelete(db, pCte->pSelect);
+  sqlite3DbFree(db, pCte->zName);
+}
+
+/*
+** Free the contents of the CTE object passed as the second argument.
+*/
+SQLITE_PRIVATE void sqlite3CteDelete(sqlite3 *db, Cte *pCte){
+  assert( pCte!=0 );
+  cteClear(db, pCte);
+  sqlite3DbFree(db, pCte);
+}
+
+/*
+** This routine is invoked once per CTE by the parser while parsing a
+** WITH clause.  The CTE described by the third argument is added to
+** the WITH clause of the second argument.  If the second argument is
+** NULL, then a new WITH argument is created.
+*/
+SQLITE_PRIVATE With *sqlite3WithAdd(
+  Parse *pParse,          /* Parsing context */
+  With *pWith,            /* Existing WITH clause, or NULL */
+  Cte *pCte               /* CTE to add to the WITH clause */
+){
+  sqlite3 *db = pParse->db;
+  With *pNew;
+  char *zName;
+
+  if( pCte==0 ){
+    return pWith;
+  }
+
+  /* Check that the CTE name is unique within this WITH clause. If
+  ** not, store an error in the Parse structure. */
+  zName = pCte->zName;
+  if( zName && pWith ){
+    int i;
+    for(i=0; i<pWith->nCte; i++){
+      if( sqlite3StrICmp(zName, pWith->a[i].zName)==0 ){
+        sqlite3ErrorMsg(pParse, "duplicate WITH table name: %s", zName);
+      }
+    }
+  }
+
+  if( pWith ){
+    sqlite3_int64 nByte = sizeof(*pWith) + (sizeof(pWith->a[1]) * pWith->nCte);
+    pNew = sqlite3DbRealloc(db, pWith, nByte);
+  }else{
+    pNew = sqlite3DbMallocZero(db, sizeof(*pWith));
+  }
+  assert( (pNew!=0 && zName!=0) || db->mallocFailed );
+
+  if( db->mallocFailed ){
+    sqlite3CteDelete(db, pCte);
+    pNew = pWith;
+  }else{
+    pNew->a[pNew->nCte++] = *pCte;
+    sqlite3DbFree(db, pCte);
+  }
+
+  return pNew;
+}
+
+/*
+** Free the contents of the With object passed as the second argument.
+*/
+SQLITE_PRIVATE void sqlite3WithDelete(sqlite3 *db, With *pWith){
+  if( pWith ){
+    int i;
+    for(i=0; i<pWith->nCte; i++){
+      cteClear(db, &pWith->a[i]);
+    }
+    sqlite3DbFree(db, pWith);
+  }
+}
+SQLITE_PRIVATE void sqlite3WithDeleteGeneric(sqlite3 *db, void *pWith){
+  sqlite3WithDelete(db, (With*)pWith);
+}
+#endif /* !defined(SQLITE_OMIT_CTE) */
+
+/************** End of build.c ***********************************************/
+/************** Begin file callback.c ****************************************/
+/*
+** 2005 May 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains functions used to access the internal hash tables
+** of user defined functions and collation sequences.
+*/
+
+/* #include "sqliteInt.h" */
+
+/*
+** Invoke the 'collation needed' callback to request a collation sequence
+** in the encoding enc of name zName, length nName.
+*/
+static void callCollNeeded(sqlite3 *db, int enc, const char *zName){
+  assert( !db->xCollNeeded || !db->xCollNeeded16 );
+  if( db->xCollNeeded ){
+    char *zExternal = sqlite3DbStrDup(db, zName);
+    if( !zExternal ) return;
+    db->xCollNeeded(db->pCollNeededArg, db, enc, zExternal);
+    sqlite3DbFree(db, zExternal);
+  }
+#ifndef SQLITE_OMIT_UTF16
+  if( db->xCollNeeded16 ){
+    char const *zExternal;
+    sqlite3_value *pTmp = sqlite3ValueNew(db);
+    sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF8, SQLITE_STATIC);
+    zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE);
+    if( zExternal ){
+      db->xCollNeeded16(db->pCollNeededArg, db, (int)ENC(db), zExternal);
+    }
+    sqlite3ValueFree(pTmp);
+  }
+#endif
+}
+
+/*
+** This routine is called if the collation factory fails to deliver a
+** collation function in the best encoding but there may be other versions
+** of this collation function (for other text encodings) available. Use one
+** of these instead if they exist. Avoid a UTF-8 <-> UTF-16 conversion if
+** possible.
+*/
+static int synthCollSeq(sqlite3 *db, CollSeq *pColl){
+  CollSeq *pColl2;
+  char *z = pColl->zName;
+  int i;
+  static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 };
+  for(i=0; i<3; i++){
+    pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, 0);
+    if( pColl2->xCmp!=0 ){
+      memcpy(pColl, pColl2, sizeof(CollSeq));
+      pColl->xDel = 0;         /* Do not copy the destructor */
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_ERROR;
+}
+
+/*
+** This routine is called on a collation sequence before it is used to
+** check that it is defined. An undefined collation sequence exists when
+** a database is loaded that contains references to collation sequences
+** that have not been defined by sqlite3_create_collation() etc.
+**
+** If required, this routine calls the 'collation needed' callback to
+** request a definition of the collating sequence. If this doesn't work,
+** an equivalent collating sequence that uses a text encoding different
+** from the main database is substituted, if one is available.
+*/
+SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){
+  if( pColl && pColl->xCmp==0 ){
+    const char *zName = pColl->zName;
+    sqlite3 *db = pParse->db;
+    CollSeq *p = sqlite3GetCollSeq(pParse, ENC(db), pColl, zName);
+    if( !p ){
+      return SQLITE_ERROR;
+    }
+    assert( p==pColl );
+  }
+  return SQLITE_OK;
+}
+
+
+
+/*
+** Locate and return an entry from the db.aCollSeq hash table. If the entry
+** specified by zName and nName is not found and parameter 'create' is
+** true, then create a new entry. Otherwise return NULL.
+**
+** Each pointer stored in the sqlite3.aCollSeq hash table contains an
+** array of three CollSeq structures. The first is the collation sequence
+** preferred for UTF-8, the second UTF-16le, and the third UTF-16be.
+**
+** Stored immediately after the three collation sequences is a copy of
+** the collation sequence name. A pointer to this string is stored in
+** each collation sequence structure.
+*/
+static CollSeq *findCollSeqEntry(
+  sqlite3 *db,          /* Database connection */
+  const char *zName,    /* Name of the collating sequence */
+  int create            /* Create a new entry if true */
+){
+  CollSeq *pColl;
+  pColl = sqlite3HashFind(&db->aCollSeq, zName);
+
+  if( 0==pColl && create ){
+    int nName = sqlite3Strlen30(zName) + 1;
+    pColl = sqlite3DbMallocZero(db, 3*sizeof(*pColl) + nName);
+    if( pColl ){
+      CollSeq *pDel = 0;
+      pColl[0].zName = (char*)&pColl[3];
+      pColl[0].enc = SQLITE_UTF8;
+      pColl[1].zName = (char*)&pColl[3];
+      pColl[1].enc = SQLITE_UTF16LE;
+      pColl[2].zName = (char*)&pColl[3];
+      pColl[2].enc = SQLITE_UTF16BE;
+      memcpy(pColl[0].zName, zName, nName);
+      pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, pColl);
+
+      /* If a malloc() failure occurred in sqlite3HashInsert(), it will
+      ** return the pColl pointer to be deleted (because it wasn't added
+      ** to the hash table).
+      */
+      assert( pDel==0 || pDel==pColl );
+      if( pDel!=0 ){
+        sqlite3OomFault(db);
+        sqlite3DbFree(db, pDel);
+        pColl = 0;
+      }
+    }
+  }
+  return pColl;
+}
+
+/*
+** Parameter zName points to a UTF-8 encoded string nName bytes long.
+** Return the CollSeq* pointer for the collation sequence named zName
+** for the encoding 'enc' from the database 'db'.
+**
+** If the entry specified is not found and 'create' is true, then create a
+** new entry.  Otherwise return NULL.
+**
+** A separate function sqlite3LocateCollSeq() is a wrapper around
+** this routine.  sqlite3LocateCollSeq() invokes the collation factory
+** if necessary and generates an error message if the collating sequence
+** cannot be found.
+**
+** See also: sqlite3LocateCollSeq(), sqlite3GetCollSeq()
+*/
+SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(
+  sqlite3 *db,          /* Database connection to search */
+  u8 enc,               /* Desired text encoding */
+  const char *zName,    /* Name of the collating sequence.  Might be NULL */
+  int create            /* True to create CollSeq if doesn't already exist */
+){
+  CollSeq *pColl;
+  assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
+  assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
+  if( zName ){
+    pColl = findCollSeqEntry(db, zName, create);
+    if( pColl ) pColl += enc-1;
+  }else{
+    pColl = db->pDfltColl;
+  }
+  return pColl;
+}
+
+/*
+** Change the text encoding for a database connection. This means that
+** the pDfltColl must change as well.
+*/
+SQLITE_PRIVATE void sqlite3SetTextEncoding(sqlite3 *db, u8 enc){
+  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
+  db->enc = enc;
+  /* EVIDENCE-OF: R-08308-17224 The default collating function for all
+  ** strings is BINARY.
+  */
+  db->pDfltColl = sqlite3FindCollSeq(db, enc, sqlite3StrBINARY, 0);
+  sqlite3ExpirePreparedStatements(db, 1);
+}
+
+/*
+** This function is responsible for invoking the collation factory callback
+** or substituting a collation sequence of a different encoding when the
+** requested collation sequence is not available in the desired encoding.
+**
+** If it is not NULL, then pColl must point to the database native encoding
+** collation sequence with name zName, length nName.
+**
+** The return value is either the collation sequence to be used in database
+** db for collation type name zName, length nName, or NULL, if no collation
+** sequence can be found.  If no collation is found, leave an error message.
+**
+** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq()
+*/
+SQLITE_PRIVATE CollSeq *sqlite3GetCollSeq(
+  Parse *pParse,        /* Parsing context */
+  u8 enc,               /* The desired encoding for the collating sequence */
+  CollSeq *pColl,       /* Collating sequence with native encoding, or NULL */
+  const char *zName     /* Collating sequence name */
+){
+  CollSeq *p;
+  sqlite3 *db = pParse->db;
+
+  p = pColl;
+  if( !p ){
+    p = sqlite3FindCollSeq(db, enc, zName, 0);
+  }
+  if( !p || !p->xCmp ){
+    /* No collation sequence of this type for this encoding is registered.
+    ** Call the collation factory to see if it can supply us with one.
+    */
+    callCollNeeded(db, enc, zName);
+    p = sqlite3FindCollSeq(db, enc, zName, 0);
+  }
+  if( p && !p->xCmp && synthCollSeq(db, p) ){
+    p = 0;
+  }
+  assert( !p || p->xCmp );
+  if( p==0 ){
+    sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
+    pParse->rc = SQLITE_ERROR_MISSING_COLLSEQ;
+  }
+  return p;
+}
+
+/*
+** This function returns the collation sequence for database native text
+** encoding identified by the string zName.
+**
+** If the requested collation sequence is not available, or not available
+** in the database native encoding, the collation factory is invoked to
+** request it. If the collation factory does not supply such a sequence,
+** and the sequence is available in another text encoding, then that is
+** returned instead.
+**
+** If no versions of the requested collations sequence are available, or
+** another error occurs, NULL is returned and an error message written into
+** pParse.
+**
+** This routine is a wrapper around sqlite3FindCollSeq().  This routine
+** invokes the collation factory if the named collation cannot be found
+** and generates an error message.
+**
+** See also: sqlite3FindCollSeq(), sqlite3GetCollSeq()
+*/
+SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName){
+  sqlite3 *db = pParse->db;
+  u8 enc = ENC(db);
+  u8 initbusy = db->init.busy;
+  CollSeq *pColl;
+
+  pColl = sqlite3FindCollSeq(db, enc, zName, initbusy);
+  if( !initbusy && (!pColl || !pColl->xCmp) ){
+    pColl = sqlite3GetCollSeq(pParse, enc, pColl, zName);
+  }
+
+  return pColl;
+}
+
+/* During the search for the best function definition, this procedure
+** is called to test how well the function passed as the first argument
+** matches the request for a function with nArg arguments in a system
+** that uses encoding enc. The value returned indicates how well the
+** request is matched. A higher value indicates a better match.
+**
+** If nArg is -1 that means to only return a match (non-zero) if p->nArg
+** is also -1.  In other words, we are searching for a function that
+** takes a variable number of arguments.
+**
+** If nArg is -2 that means that we are searching for any function
+** regardless of the number of arguments it uses, so return a positive
+** match score for any
+**
+** The returned value is always between 0 and 6, as follows:
+**
+** 0: Not a match.
+** 1: UTF8/16 conversion required and function takes any number of arguments.
+** 2: UTF16 byte order change required and function takes any number of args.
+** 3: encoding matches and function takes any number of arguments
+** 4: UTF8/16 conversion required - argument count matches exactly
+** 5: UTF16 byte order conversion required - argument count matches exactly
+** 6: Perfect match:  encoding and argument count match exactly.
+**
+** If nArg==(-2) then any function with a non-null xSFunc is
+** a perfect match and any function with xSFunc NULL is
+** a non-match.
+*/
+#define FUNC_PERFECT_MATCH 6  /* The score for a perfect match */
+static int matchQuality(
+  FuncDef *p,     /* The function we are evaluating for match quality */
+  int nArg,       /* Desired number of arguments.  (-1)==any */
+  u8 enc          /* Desired text encoding */
+){
+  int match;
+  assert( p->nArg>=(-4) && p->nArg!=(-2) );
+  assert( nArg>=(-2) );
+
+  /* Wrong number of arguments means "no match" */
+  if( p->nArg!=nArg ){
+    if( nArg==(-2) ) return p->xSFunc==0 ? 0 : FUNC_PERFECT_MATCH;
+    if( p->nArg>=0 ) return 0;
+    /* Special p->nArg values available to built-in functions only:
+    **    -3     1 or more arguments required
+    **    -4     2 or more arguments required
+    */
+    if( p->nArg<(-2) && nArg<(-2-p->nArg) ) return 0;
+  }
+
+  /* Give a better score to a function with a specific number of arguments
+  ** than to function that accepts any number of arguments. */
+  if( p->nArg==nArg ){
+    match = 4;
+  }else{
+    match = 1;
+  }
+
+  /* Bonus points if the text encoding matches */
+  if( enc==(p->funcFlags & SQLITE_FUNC_ENCMASK) ){
+    match += 2;  /* Exact encoding match */
+  }else if( (enc & p->funcFlags & 2)!=0 ){
+    match += 1;  /* Both are UTF16, but with different byte orders */
+  }
+
+  return match;
+}
+
+/*
+** Search a FuncDefHash for a function with the given name.  Return
+** a pointer to the matching FuncDef if found, or 0 if there is no match.
+*/
+SQLITE_PRIVATE FuncDef *sqlite3FunctionSearch(
+  int h,               /* Hash of the name */
+  const char *zFunc    /* Name of function */
+){
+  FuncDef *p;
+  for(p=sqlite3BuiltinFunctions.a[h]; p; p=p->u.pHash){
+    assert( p->funcFlags & SQLITE_FUNC_BUILTIN );
+    if( sqlite3StrICmp(p->zName, zFunc)==0 ){
+      return p;
+    }
+  }
+  return 0;
+}
+
+/*
+** Insert a new FuncDef into a FuncDefHash hash table.
+*/
+SQLITE_PRIVATE void sqlite3InsertBuiltinFuncs(
+  FuncDef *aDef,      /* List of global functions to be inserted */
+  int nDef            /* Length of the apDef[] list */
+){
+  int i;
+  for(i=0; i<nDef; i++){
+    FuncDef *pOther;
+    const char *zName = aDef[i].zName;
+    int nName = sqlite3Strlen30(zName);
+    int h = SQLITE_FUNC_HASH(zName[0], nName);
+    assert( aDef[i].funcFlags & SQLITE_FUNC_BUILTIN );
+    pOther = sqlite3FunctionSearch(h, zName);
+    if( pOther ){
+      assert( pOther!=&aDef[i] && pOther->pNext!=&aDef[i] );
+      aDef[i].pNext = pOther->pNext;
+      pOther->pNext = &aDef[i];
+    }else{
+      aDef[i].pNext = 0;
+      aDef[i].u.pHash = sqlite3BuiltinFunctions.a[h];
+      sqlite3BuiltinFunctions.a[h] = &aDef[i];
+    }
+  }
+}
+
+
+
+/*
+** Locate a user function given a name, a number of arguments and a flag
+** indicating whether the function prefers UTF-16 over UTF-8.  Return a
+** pointer to the FuncDef structure that defines that function, or return
+** NULL if the function does not exist.
+**
+** If the createFlag argument is true, then a new (blank) FuncDef
+** structure is created and liked into the "db" structure if a
+** no matching function previously existed.
+**
+** If nArg is -2, then the first valid function found is returned.  A
+** function is valid if xSFunc is non-zero.  The nArg==(-2)
+** case is used to see if zName is a valid function name for some number
+** of arguments.  If nArg is -2, then createFlag must be 0.
+**
+** If createFlag is false, then a function with the required name and
+** number of arguments may be returned even if the eTextRep flag does not
+** match that requested.
+*/
+SQLITE_PRIVATE FuncDef *sqlite3FindFunction(
+  sqlite3 *db,       /* An open database */
+  const char *zName, /* Name of the function.  zero-terminated */
+  int nArg,          /* Number of arguments.  -1 means any number */
+  u8 enc,            /* Preferred text encoding */
+  u8 createFlag      /* Create new entry if true and does not otherwise exist */
+){
+  FuncDef *p;         /* Iterator variable */
+  FuncDef *pBest = 0; /* Best match found so far */
+  int bestScore = 0;  /* Score of best match */
+  int h;              /* Hash value */
+  int nName;          /* Length of the name */
+
+  assert( nArg>=(-2) );
+  assert( nArg>=(-1) || createFlag==0 );
+  nName = sqlite3Strlen30(zName);
+
+  /* First search for a match amongst the application-defined functions.
+  */
+  p = (FuncDef*)sqlite3HashFind(&db->aFunc, zName);
+  while( p ){
+    int score = matchQuality(p, nArg, enc);
+    if( score>bestScore ){
+      pBest = p;
+      bestScore = score;
+    }
+    p = p->pNext;
+  }
+
+  /* If no match is found, search the built-in functions.
+  **
+  ** If the DBFLAG_PreferBuiltin flag is set, then search the built-in
+  ** functions even if a prior app-defined function was found.  And give
+  ** priority to built-in functions.
+  **
+  ** Except, if createFlag is true, that means that we are trying to
+  ** install a new function.  Whatever FuncDef structure is returned it will
+  ** have fields overwritten with new information appropriate for the
+  ** new function.  But the FuncDefs for built-in functions are read-only.
+  ** So we must not search for built-ins when creating a new function.
+  */
+  if( !createFlag && (pBest==0 || (db->mDbFlags & DBFLAG_PreferBuiltin)!=0) ){
+    bestScore = 0;
+    h = SQLITE_FUNC_HASH(sqlite3UpperToLower[(u8)zName[0]], nName);
+    p = sqlite3FunctionSearch(h, zName);
+    while( p ){
+      int score = matchQuality(p, nArg, enc);
+      if( score>bestScore ){
+        pBest = p;
+        bestScore = score;
+      }
+      p = p->pNext;
+    }
+  }
+
+  /* If the createFlag parameter is true and the search did not reveal an
+  ** exact match for the name, number of arguments and encoding, then add a
+  ** new entry to the hash table and return it.
+  */
+  if( createFlag && bestScore<FUNC_PERFECT_MATCH &&
+      (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
+    FuncDef *pOther;
+    u8 *z;
+    pBest->zName = (const char*)&pBest[1];
+    pBest->nArg = (u16)nArg;
+    pBest->funcFlags = enc;
+    memcpy((char*)&pBest[1], zName, nName+1);
+    for(z=(u8*)pBest->zName; *z; z++) *z = sqlite3UpperToLower[*z];
+    pOther = (FuncDef*)sqlite3HashInsert(&db->aFunc, pBest->zName, pBest);
+    if( pOther==pBest ){
+      sqlite3DbFree(db, pBest);
+      sqlite3OomFault(db);
+      return 0;
+    }else{
+      pBest->pNext = pOther;
+    }
+  }
+
+  if( pBest && (pBest->xSFunc || createFlag) ){
+    return pBest;
+  }
+  return 0;
+}
+
+/*
+** Free all resources held by the schema structure. The void* argument points
+** at a Schema struct. This function does not call sqlite3DbFree(db, ) on the
+** pointer itself, it just cleans up subsidiary resources (i.e. the contents
+** of the schema hash tables).
+**
+** The Schema.cache_size variable is not cleared.
+*/
+SQLITE_PRIVATE void sqlite3SchemaClear(void *p){
+  Hash temp1;
+  Hash temp2;
+  HashElem *pElem;
+  Schema *pSchema = (Schema *)p;
+  sqlite3 xdb;
+
+  memset(&xdb, 0, sizeof(xdb));
+  temp1 = pSchema->tblHash;
+  temp2 = pSchema->trigHash;
+  sqlite3HashInit(&pSchema->trigHash);
+  sqlite3HashClear(&pSchema->idxHash);
+  for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){
+    sqlite3DeleteTrigger(&xdb, (Trigger*)sqliteHashData(pElem));
+  }
+  sqlite3HashClear(&temp2);
+  sqlite3HashInit(&pSchema->tblHash);
+  for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){
+    Table *pTab = sqliteHashData(pElem);
+    sqlite3DeleteTable(&xdb, pTab);
+  }
+  sqlite3HashClear(&temp1);
+  sqlite3HashClear(&pSchema->fkeyHash);
+  pSchema->pSeqTab = 0;
+  if( pSchema->schemaFlags & DB_SchemaLoaded ){
+    pSchema->iGeneration++;
+  }
+  pSchema->schemaFlags &= ~(DB_SchemaLoaded|DB_ResetWanted);
+}
+
+/*
+** Find and return the schema associated with a BTree.  Create
+** a new one if necessary.
+*/
+SQLITE_PRIVATE Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
+  Schema * p;
+  if( pBt ){
+    p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear);
+  }else{
+    p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema));
+  }
+  if( !p ){
+    sqlite3OomFault(db);
+  }else if ( 0==p->file_format ){
+    sqlite3HashInit(&p->tblHash);
+    sqlite3HashInit(&p->idxHash);
+    sqlite3HashInit(&p->trigHash);
+    sqlite3HashInit(&p->fkeyHash);
+    p->enc = SQLITE_UTF8;
+  }
+  return p;
+}
+
+/************** End of callback.c ********************************************/
+/************** Begin file delete.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** in order to generate code for DELETE FROM statements.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** While a SrcList can in general represent multiple tables and subqueries
+** (as in the FROM clause of a SELECT statement) in this case it contains
+** the name of a single table, as one might find in an INSERT, DELETE,
+** or UPDATE statement.  Look up that table in the symbol table and
+** return a pointer.  Set an error message and return NULL if the table
+** name is not found or if any other error occurs.
+**
+** The following fields are initialized appropriate in pSrc:
+**
+**    pSrc->a[0].spTab        Pointer to the Table object
+**    pSrc->a[0].u2.pIBIndex  Pointer to the INDEXED BY index, if there is one
+**
+*/
+SQLITE_PRIVATE Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
+  SrcItem *pItem = pSrc->a;
+  Table *pTab;
+  assert( pItem && pSrc->nSrc>=1 );
+  pTab = sqlite3LocateTableItem(pParse, 0, pItem);
+  if( pItem->pSTab ) sqlite3DeleteTable(pParse->db, pItem->pSTab);
+  pItem->pSTab = pTab;
+  pItem->fg.notCte = 1;
+  if( pTab ){
+    pTab->nTabRef++;
+    if( pItem->fg.isIndexedBy && sqlite3IndexedByLookup(pParse, pItem) ){
+      pTab = 0;
+    }
+  }
+  return pTab;
+}
+
+/* Generate byte-code that will report the number of rows modified
+** by a DELETE, INSERT, or UPDATE statement.
+*/
+SQLITE_PRIVATE void sqlite3CodeChangeCount(Vdbe *v, int regCounter, const char *zColName){
+  sqlite3VdbeAddOp0(v, OP_FkCheck);
+  sqlite3VdbeAddOp2(v, OP_ResultRow, regCounter, 1);
+  sqlite3VdbeSetNumCols(v, 1);
+  sqlite3VdbeSetColName(v, 0, COLNAME_NAME, zColName, SQLITE_STATIC);
+}
+
+/* Return true if table pTab is read-only.
+**
+** A table is read-only if any of the following are true:
+**
+**   1) It is a virtual table and no implementation of the xUpdate method
+**      has been provided
+**
+**   2) A trigger is currently being coded and the table is a virtual table
+**      that is SQLITE_VTAB_DIRECTONLY or if PRAGMA trusted_schema=OFF and
+**      the table is not SQLITE_VTAB_INNOCUOUS.
+**
+**   3) It is a system table (i.e. sqlite_schema), this call is not
+**      part of a nested parse and writable_schema pragma has not
+**      been specified
+**
+**   4) The table is a shadow table, the database connection is in
+**      defensive mode, and the current sqlite3_prepare()
+**      is for a top-level SQL statement.
+*/
+static int vtabIsReadOnly(Parse *pParse, Table *pTab){
+  assert( IsVirtual(pTab) );
+  if( sqlite3GetVTable(pParse->db, pTab)->pMod->pModule->xUpdate==0 ){
+    return 1;
+  }
+
+  /* Within triggers:
+  **   *  Do not allow DELETE, INSERT, or UPDATE of SQLITE_VTAB_DIRECTONLY
+  **      virtual tables
+  **   *  Only allow DELETE, INSERT, or UPDATE of non-SQLITE_VTAB_INNOCUOUS
+  **      virtual tables if PRAGMA trusted_schema=ON.
+  */
+  if( pParse->pToplevel!=0
+   && pTab->u.vtab.p->eVtabRisk >
+           ((pParse->db->flags & SQLITE_TrustedSchema)!=0)
+  ){
+    sqlite3ErrorMsg(pParse, "unsafe use of virtual table \"%s\"",
+      pTab->zName);
+  }
+  return 0;
+}
+static int tabIsReadOnly(Parse *pParse, Table *pTab){
+  sqlite3 *db;
+  if( IsVirtual(pTab) ){
+    return vtabIsReadOnly(pParse, pTab);
+  }
+  if( (pTab->tabFlags & (TF_Readonly|TF_Shadow))==0 ) return 0;
+  db = pParse->db;
+  if( (pTab->tabFlags & TF_Readonly)!=0 ){
+    return sqlite3WritableSchema(db)==0 && pParse->nested==0;
+  }
+  assert( pTab->tabFlags & TF_Shadow );
+  return sqlite3ReadOnlyShadowTables(db);
+}
+
+/*
+** Check to make sure the given table is writable.
+**
+** If pTab is not writable  ->  generate an error message and return 1.
+** If pTab is writable but other errors have occurred -> return 1.
+** If pTab is writable and no prior errors -> return 0;
+*/
+SQLITE_PRIVATE int sqlite3IsReadOnly(Parse *pParse, Table *pTab, Trigger *pTrigger){
+  if( tabIsReadOnly(pParse, pTab) ){
+    sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
+    return 1;
+  }
+#ifndef SQLITE_OMIT_VIEW
+  if( IsView(pTab)
+   && (pTrigger==0 || (pTrigger->bReturning && pTrigger->pNext==0))
+  ){
+    sqlite3ErrorMsg(pParse,"cannot modify %s because it is a view",pTab->zName);
+    return 1;
+  }
+#endif
+  return 0;
+}
+
+
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+/*
+** Evaluate a view and store its result in an ephemeral table.  The
+** pWhere argument is an optional WHERE clause that restricts the
+** set of rows in the view that are to be added to the ephemeral table.
+*/
+SQLITE_PRIVATE void sqlite3MaterializeView(
+  Parse *pParse,       /* Parsing context */
+  Table *pView,        /* View definition */
+  Expr *pWhere,        /* Optional WHERE clause to be added */
+  ExprList *pOrderBy,  /* Optional ORDER BY clause */
+  Expr *pLimit,        /* Optional LIMIT clause */
+  int iCur             /* Cursor number for ephemeral table */
+){
+  SelectDest dest;
+  Select *pSel;
+  SrcList *pFrom;
+  sqlite3 *db = pParse->db;
+  int iDb = sqlite3SchemaToIndex(db, pView->pSchema);
+  pWhere = sqlite3ExprDup(db, pWhere, 0);
+  pFrom = sqlite3SrcListAppend(pParse, 0, 0, 0);
+  if( pFrom ){
+    assert( pFrom->nSrc==1 );
+    pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName);
+    assert( pFrom->a[0].fg.fixedSchema==0 && pFrom->a[0].fg.isSubquery==0 );
+    pFrom->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
+    assert( pFrom->a[0].fg.isUsing==0 );
+    assert( pFrom->a[0].u3.pOn==0 );
+  }
+  pSel = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, pOrderBy,
+                          SF_IncludeHidden, pLimit);
+  sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
+  sqlite3Select(pParse, pSel, &dest);
+  sqlite3SelectDelete(db, pSel);
+}
+#endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */
+
+#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
+/*
+** Generate an expression tree to implement the WHERE, ORDER BY,
+** and LIMIT/OFFSET portion of DELETE and UPDATE statements.
+**
+**     DELETE FROM table_wxyz WHERE a<5 ORDER BY a LIMIT 1;
+**                            \__________________________/
+**                               pLimitWhere (pInClause)
+*/
+SQLITE_PRIVATE Expr *sqlite3LimitWhere(
+  Parse *pParse,               /* The parser context */
+  SrcList *pSrc,               /* the FROM clause -- which tables to scan */
+  Expr *pWhere,                /* The WHERE clause.  May be null */
+  ExprList *pOrderBy,          /* The ORDER BY clause.  May be null */
+  Expr *pLimit,                /* The LIMIT clause.  May be null */
+  char *zStmtType              /* Either DELETE or UPDATE.  For err msgs. */
+){
+  sqlite3 *db = pParse->db;
+  Expr *pLhs = NULL;           /* LHS of IN(SELECT...) operator */
+  Expr *pInClause = NULL;      /* WHERE rowid IN ( select ) */
+  ExprList *pEList = NULL;     /* Expression list containing only pSelectRowid*/
+  SrcList *pSelectSrc = NULL;  /* SELECT rowid FROM x ... (dup of pSrc) */
+  Select *pSelect = NULL;      /* Complete SELECT tree */
+  Table *pTab;
+
+  /* Check that there isn't an ORDER BY without a LIMIT clause.
+  */
+  if( pOrderBy && pLimit==0 ) {
+    sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on %s", zStmtType);
+    sqlite3ExprDelete(pParse->db, pWhere);
+    sqlite3ExprListDelete(pParse->db, pOrderBy);
+    return 0;
+  }
+
+  /* We only need to generate a select expression if there
+  ** is a limit/offset term to enforce.
+  */
+  if( pLimit == 0 ) {
+    return pWhere;
+  }
+
+  /* Generate a select expression tree to enforce the limit/offset
+  ** term for the DELETE or UPDATE statement.  For example:
+  **   DELETE FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
+  ** becomes:
+  **   DELETE FROM table_a WHERE rowid IN (
+  **     SELECT rowid FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1
+  **   );
+  */
+
+  pTab = pSrc->a[0].pSTab;
+  if( HasRowid(pTab) ){
+    pLhs = sqlite3PExpr(pParse, TK_ROW, 0, 0);
+    pEList = sqlite3ExprListAppend(
+        pParse, 0, sqlite3PExpr(pParse, TK_ROW, 0, 0)
+    );
+  }else{
+    Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+    assert( pPk!=0 );
+    assert( pPk->nKeyCol>=1 );
+    if( pPk->nKeyCol==1 ){
+      const char *zName;
+      assert( pPk->aiColumn[0]>=0 && pPk->aiColumn[0]<pTab->nCol );
+      zName = pTab->aCol[pPk->aiColumn[0]].zCnName;
+      pLhs = sqlite3Expr(db, TK_ID, zName);
+      pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ID, zName));
+    }else{
+      int i;
+      for(i=0; i<pPk->nKeyCol; i++){
+        Expr *p;
+        assert( pPk->aiColumn[i]>=0 && pPk->aiColumn[i]<pTab->nCol );
+        p = sqlite3Expr(db, TK_ID, pTab->aCol[pPk->aiColumn[i]].zCnName);
+        pEList = sqlite3ExprListAppend(pParse, pEList, p);
+      }
+      pLhs = sqlite3PExpr(pParse, TK_VECTOR, 0, 0);
+      if( pLhs ){
+        pLhs->x.pList = sqlite3ExprListDup(db, pEList, 0);
+      }
+    }
+  }
+
+  /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
+  ** and the SELECT subtree. */
+  pSrc->a[0].pSTab = 0;
+  pSelectSrc = sqlite3SrcListDup(db, pSrc, 0);
+  pSrc->a[0].pSTab = pTab;
+  if( pSrc->a[0].fg.isIndexedBy ){
+    assert( pSrc->a[0].fg.isCte==0 );
+    pSrc->a[0].u2.pIBIndex = 0;
+    pSrc->a[0].fg.isIndexedBy = 0;
+    sqlite3DbFree(db, pSrc->a[0].u1.zIndexedBy);
+  }else if( pSrc->a[0].fg.isCte ){
+    pSrc->a[0].u2.pCteUse->nUse++;
+  }
+
+  /* generate the SELECT expression tree. */
+  pSelect = sqlite3SelectNew(pParse, pEList, pSelectSrc, pWhere, 0 ,0,
+      pOrderBy,0,pLimit
+  );
+
+  /* now generate the new WHERE rowid IN clause for the DELETE/UPDATE */
+  pInClause = sqlite3PExpr(pParse, TK_IN, pLhs, 0);
+  sqlite3PExprAddSelect(pParse, pInClause, pSelect);
+  return pInClause;
+}
+#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) */
+       /*      && !defined(SQLITE_OMIT_SUBQUERY) */
+
+/*
+** Generate code for a DELETE FROM statement.
+**
+**     DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
+**                 \________/       \________________/
+**                  pTabList              pWhere
+*/
+SQLITE_PRIVATE void sqlite3DeleteFrom(
+  Parse *pParse,         /* The parser context */
+  SrcList *pTabList,     /* The table from which we should delete things */
+  Expr *pWhere,          /* The WHERE clause.  May be null */
+  ExprList *pOrderBy,    /* ORDER BY clause. May be null */
+  Expr *pLimit           /* LIMIT clause. May be null */
+){
+  Vdbe *v;               /* The virtual database engine */
+  Table *pTab;           /* The table from which records will be deleted */
+  int i;                 /* Loop counter */
+  WhereInfo *pWInfo;     /* Information about the WHERE clause */
+  Index *pIdx;           /* For looping over indices of the table */
+  int iTabCur;           /* Cursor number for the table */
+  int iDataCur = 0;      /* VDBE cursor for the canonical data source */
+  int iIdxCur = 0;       /* Cursor number of the first index */
+  int nIdx;              /* Number of indices */
+  sqlite3 *db;           /* Main database structure */
+  AuthContext sContext;  /* Authorization context */
+  NameContext sNC;       /* Name context to resolve expressions in */
+  int iDb;               /* Database number */
+  int memCnt = 0;        /* Memory cell used for change counting */
+  int rcauth;            /* Value returned by authorization callback */
+  int eOnePass;          /* ONEPASS_OFF or _SINGLE or _MULTI */
+  int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */
+  u8 *aToOpen = 0;       /* Open cursor iTabCur+j if aToOpen[j] is true */
+  Index *pPk;            /* The PRIMARY KEY index on the table */
+  int iPk = 0;           /* First of nPk registers holding PRIMARY KEY value */
+  i16 nPk = 1;           /* Number of columns in the PRIMARY KEY */
+  int iKey;              /* Memory cell holding key of row to be deleted */
+  i16 nKey;              /* Number of memory cells in the row key */
+  int iEphCur = 0;       /* Ephemeral table holding all primary key values */
+  int iRowSet = 0;       /* Register for rowset of rows to delete */
+  int addrBypass = 0;    /* Address of jump over the delete logic */
+  int addrLoop = 0;      /* Top of the delete loop */
+  int addrEphOpen = 0;   /* Instruction to open the Ephemeral table */
+  int bComplex;          /* True if there are triggers or FKs or
+                         ** subqueries in the WHERE clause */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;                  /* True if attempting to delete from a view */
+  Trigger *pTrigger;           /* List of table triggers, if required */
+#endif
+
+  memset(&sContext, 0, sizeof(sContext));
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nErr ){
+    goto delete_from_cleanup;
+  }
+  assert( db->mallocFailed==0 );
+  assert( pTabList->nSrc==1 );
+
+  /* Locate the table which we want to delete.  This table has to be
+  ** put in an SrcList structure because some of the subroutines we
+  ** will be calling are designed to work with multiple tables and expect
+  ** an SrcList* parameter instead of just a Table* parameter.
+  */
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 )  goto delete_from_cleanup;
+
+  /* Figure out if we have any triggers and if the table being
+  ** deleted from is a view
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
+  isView = IsView(pTab);
+#else
+# define pTrigger 0
+# define isView 0
+#endif
+  bComplex = pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0);
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x10000 ){
+    sqlite3TreeViewLine(0, "In sqlite3Delete() at %s:%d", __FILE__, __LINE__);
+    sqlite3TreeViewDelete(pParse->pWith, pTabList, pWhere,
+                          pOrderBy, pLimit, pTrigger);
+  }
+#endif
+
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( !isView ){
+    pWhere = sqlite3LimitWhere(
+        pParse, pTabList, pWhere, pOrderBy, pLimit, "DELETE"
+    );
+    pOrderBy = 0;
+    pLimit = 0;
+  }
+#endif
+
+  /* If pTab is really a view, make sure it has been initialized.
+  */
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto delete_from_cleanup;
+  }
+
+  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
+    goto delete_from_cleanup;
+  }
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb<db->nDb );
+  rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0,
+                            db->aDb[iDb].zDbSName);
+  assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE );
+  if( rcauth==SQLITE_DENY ){
+    goto delete_from_cleanup;
+  }
+  assert(!isView || pTrigger);
+
+  /* Assign cursor numbers to the table and all its indices.
+  */
+  assert( pTabList->nSrc==1 );
+  iTabCur = pTabList->a[0].iCursor = pParse->nTab++;
+  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
+    pParse->nTab++;
+  }
+
+  /* Start the view context
+  */
+  if( isView ){
+    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
+  }
+
+  /* Begin generating code.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ){
+    goto delete_from_cleanup;
+  }
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, bComplex, iDb);
+
+  /* If we are trying to delete from a view, realize that view into
+  ** an ephemeral table.
+  */
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+  if( isView ){
+    sqlite3MaterializeView(pParse, pTab,
+        pWhere, pOrderBy, pLimit, iTabCur
+    );
+    iDataCur = iIdxCur = iTabCur;
+    pOrderBy = 0;
+    pLimit = 0;
+  }
+#endif
+
+  /* Resolve the column names in the WHERE clause.
+  */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  sNC.pSrcList = pTabList;
+  if( sqlite3ResolveExprNames(&sNC, pWhere) ){
+    goto delete_from_cleanup;
+  }
+
+  /* Initialize the counter of the number of rows deleted, if
+  ** we are counting rows.
+  */
+  if( (db->flags & SQLITE_CountRows)!=0
+   && !pParse->nested
+   && !pParse->pTriggerTab
+   && !pParse->bReturning
+  ){
+    memCnt = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt);
+  }
+
+#ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
+  /* Special case: A DELETE without a WHERE clause deletes everything.
+  ** It is easier just to erase the whole table. Prior to version 3.6.5,
+  ** this optimization caused the row change count (the value returned by
+  ** API function sqlite3_count_changes) to be set incorrectly.
+  **
+  ** The "rcauth==SQLITE_OK" terms is the
+  ** IMPLEMENTATION-OF: R-17228-37124 If the action code is SQLITE_DELETE and
+  ** the callback returns SQLITE_IGNORE then the DELETE operation proceeds but
+  ** the truncate optimization is disabled and all rows are deleted
+  ** individually.
+  */
+  if( rcauth==SQLITE_OK
+   && pWhere==0
+   && !bComplex
+   && !IsVirtual(pTab)
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+   && db->xPreUpdateCallback==0
+#endif
+  ){
+    assert( !isView );
+    sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName);
+    if( HasRowid(pTab) ){
+      sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt ? memCnt : -1,
+                        pTab->zName, P4_STATIC);
+    }
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      assert( pIdx->pSchema==pTab->pSchema );
+      if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
+        sqlite3VdbeAddOp3(v, OP_Clear, pIdx->tnum, iDb, memCnt ? memCnt : -1);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb);
+      }
+    }
+  }else
+#endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */
+  {
+    u16 wcf = WHERE_ONEPASS_DESIRED|WHERE_DUPLICATES_OK;
+    if( sNC.ncFlags & NC_Subquery ) bComplex = 1;
+    wcf |= (bComplex ? 0 : WHERE_ONEPASS_MULTIROW);
+    if( HasRowid(pTab) ){
+      /* For a rowid table, initialize the RowSet to an empty set */
+      pPk = 0;
+      assert( nPk==1 );
+      iRowSet = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
+    }else{
+      /* For a WITHOUT ROWID table, create an ephemeral table used to
+      ** hold all primary keys for rows to be deleted. */
+      pPk = sqlite3PrimaryKeyIndex(pTab);
+      assert( pPk!=0 );
+      nPk = pPk->nKeyCol;
+      iPk = pParse->nMem+1;
+      pParse->nMem += nPk;
+      iEphCur = pParse->nTab++;
+      addrEphOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEphCur, nPk);
+      sqlite3VdbeSetP4KeyInfo(pParse, pPk);
+    }
+
+    /* Construct a query to find the rowid or primary key for every row
+    ** to be deleted, based on the WHERE clause. Set variable eOnePass
+    ** to indicate the strategy used to implement this delete:
+    **
+    **  ONEPASS_OFF:    Two-pass approach - use a FIFO for rowids/PK values.
+    **  ONEPASS_SINGLE: One-pass approach - at most one row deleted.
+    **  ONEPASS_MULTI:  One-pass approach - any number of rows may be deleted.
+    */
+    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0,0,wcf,iTabCur+1);
+    if( pWInfo==0 ) goto delete_from_cleanup;
+    eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
+    assert( IsVirtual(pTab)==0 || eOnePass!=ONEPASS_MULTI );
+    assert( IsVirtual(pTab) || bComplex || eOnePass!=ONEPASS_OFF
+            || OptimizationDisabled(db, SQLITE_OnePass) );
+    if( eOnePass!=ONEPASS_SINGLE ) sqlite3MultiWrite(pParse);
+    if( sqlite3WhereUsesDeferredSeek(pWInfo) ){
+      sqlite3VdbeAddOp1(v, OP_FinishSeek, iTabCur);
+    }
+
+    /* Keep track of the number of rows to be deleted */
+    if( memCnt ){
+      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
+    }
+
+    /* Extract the rowid or primary key for the current row */
+    if( pPk ){
+      for(i=0; i<nPk; i++){
+        assert( pPk->aiColumn[i]>=0 );
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur,
+                                        pPk->aiColumn[i], iPk+i);
+      }
+      iKey = iPk;
+    }else{
+      iKey = ++pParse->nMem;
+      sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, -1, iKey);
+    }
+
+    if( eOnePass!=ONEPASS_OFF ){
+      /* For ONEPASS, no need to store the rowid/primary-key. There is only
+      ** one, so just keep it in its register(s) and fall through to the
+      ** delete code.  */
+      nKey = nPk; /* OP_Found will use an unpacked key */
+      aToOpen = sqlite3DbMallocRawNN(db, nIdx+2);
+      if( aToOpen==0 ){
+        sqlite3WhereEnd(pWInfo);
+        goto delete_from_cleanup;
+      }
+      memset(aToOpen, 1, nIdx+1);
+      aToOpen[nIdx+1] = 0;
+      if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iTabCur] = 0;
+      if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iTabCur] = 0;
+      if( addrEphOpen ) sqlite3VdbeChangeToNoop(v, addrEphOpen);
+      addrBypass = sqlite3VdbeMakeLabel(pParse);
+    }else{
+      if( pPk ){
+        /* Add the PK key for this row to the temporary table */
+        iKey = ++pParse->nMem;
+        nKey = 0;   /* Zero tells OP_Found to use a composite key */
+        sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, iKey,
+            sqlite3IndexAffinityStr(pParse->db, pPk), nPk);
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEphCur, iKey, iPk, nPk);
+      }else{
+        /* Add the rowid of the row to be deleted to the RowSet */
+        nKey = 1;  /* OP_DeferredSeek always uses a single rowid */
+        sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, iKey);
+      }
+      sqlite3WhereEnd(pWInfo);
+    }
+
+    /* Unless this is a view, open cursors for the table we are
+    ** deleting from and all its indices. If this is a view, then the
+    ** only effect this statement has is to fire the INSTEAD OF
+    ** triggers.
+    */
+    if( !isView ){
+      int iAddrOnce = 0;
+      if( eOnePass==ONEPASS_MULTI ){
+        iAddrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+      }
+      testcase( IsVirtual(pTab) );
+      sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, OPFLAG_FORDELETE,
+                                 iTabCur, aToOpen, &iDataCur, &iIdxCur);
+      assert( pPk || IsVirtual(pTab) || iDataCur==iTabCur );
+      assert( pPk || IsVirtual(pTab) || iIdxCur==iDataCur+1 );
+      if( eOnePass==ONEPASS_MULTI ){
+        sqlite3VdbeJumpHereOrPopInst(v, iAddrOnce);
+      }
+    }
+
+    /* Set up a loop over the rowids/primary-keys that were found in the
+    ** where-clause loop above.
+    */
+    if( eOnePass!=ONEPASS_OFF ){
+      assert( nKey==nPk );  /* OP_Found will use an unpacked key */
+      if( !IsVirtual(pTab) && aToOpen[iDataCur-iTabCur] ){
+        assert( pPk!=0 || IsView(pTab) );
+        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey);
+        VdbeCoverage(v);
+      }
+    }else if( pPk ){
+      addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur); VdbeCoverage(v);
+      if( IsVirtual(pTab) ){
+        sqlite3VdbeAddOp3(v, OP_Column, iEphCur, 0, iKey);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_RowData, iEphCur, iKey);
+      }
+      assert( nKey==0 );  /* OP_Found will use a composite key */
+    }else{
+      addrLoop = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, 0, iKey);
+      VdbeCoverage(v);
+      assert( nKey==1 );
+    }
+
+    /* Delete the row */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( IsVirtual(pTab) ){
+      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
+      sqlite3VtabMakeWritable(pParse, pTab);
+      assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE );
+      sqlite3MayAbort(pParse);
+      if( eOnePass==ONEPASS_SINGLE ){
+        sqlite3VdbeAddOp1(v, OP_Close, iTabCur);
+        if( sqlite3IsToplevel(pParse) ){
+          pParse->isMultiWrite = 0;
+        }
+      }
+      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iKey, pVTab, P4_VTAB);
+      sqlite3VdbeChangeP5(v, OE_Abort);
+    }else
+#endif
+    {
+      int count = (pParse->nested==0);    /* True to count changes */
+      sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
+          iKey, nKey, count, OE_Default, eOnePass, aiCurOnePass[1]);
+    }
+
+    /* End of the loop over all rowids/primary-keys. */
+    if( eOnePass!=ONEPASS_OFF ){
+      sqlite3VdbeResolveLabel(v, addrBypass);
+      sqlite3WhereEnd(pWInfo);
+    }else if( pPk ){
+      sqlite3VdbeAddOp2(v, OP_Next, iEphCur, addrLoop+1); VdbeCoverage(v);
+      sqlite3VdbeJumpHere(v, addrLoop);
+    }else{
+      sqlite3VdbeGoto(v, addrLoop);
+      sqlite3VdbeJumpHere(v, addrLoop);
+    }
+  } /* End non-truncate path */
+
+  /* Update the sqlite_sequence table by storing the content of the
+  ** maximum rowid counter values recorded while inserting into
+  ** autoincrement tables.
+  */
+  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
+    sqlite3AutoincrementEnd(pParse);
+  }
+
+  /* Return the number of rows that were deleted. If this routine is
+  ** generating code because of a call to sqlite3NestedParse(), do not
+  ** invoke the callback function.
+  */
+  if( memCnt ){
+    sqlite3CodeChangeCount(v, memCnt, "rows deleted");
+  }
+
+delete_from_cleanup:
+  sqlite3AuthContextPop(&sContext);
+  sqlite3SrcListDelete(db, pTabList);
+  sqlite3ExprDelete(db, pWhere);
+#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT)
+  sqlite3ExprListDelete(db, pOrderBy);
+  sqlite3ExprDelete(db, pLimit);
+#endif
+  if( aToOpen ) sqlite3DbNNFreeNN(db, aToOpen);
+  return;
+}
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** they may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
+
+/*
+** This routine generates VDBE code that causes a single row of a
+** single table to be deleted.  Both the original table entry and
+** all indices are removed.
+**
+** Preconditions:
+**
+**   1.  iDataCur is an open cursor on the btree that is the canonical data
+**       store for the table.  (This will be either the table itself,
+**       in the case of a rowid table, or the PRIMARY KEY index in the case
+**       of a WITHOUT ROWID table.)
+**
+**   2.  Read/write cursors for all indices of pTab must be open as
+**       cursor number iIdxCur+i for the i-th index.
+**
+**   3.  The primary key for the row to be deleted must be stored in a
+**       sequence of nPk memory cells starting at iPk.  If nPk==0 that means
+**       that a search record formed from OP_MakeRecord is contained in the
+**       single memory location iPk.
+**
+** eMode:
+**   Parameter eMode may be passed either ONEPASS_OFF (0), ONEPASS_SINGLE, or
+**   ONEPASS_MULTI.  If eMode is not ONEPASS_OFF, then the cursor
+**   iDataCur already points to the row to delete. If eMode is ONEPASS_OFF
+**   then this function must seek iDataCur to the entry identified by iPk
+**   and nPk before reading from it.
+**
+**   If eMode is ONEPASS_MULTI, then this call is being made as part
+**   of a ONEPASS delete that affects multiple rows. In this case, if
+**   iIdxNoSeek is a valid cursor number (>=0) and is not the same as
+**   iDataCur, then its position should be preserved following the delete
+**   operation. Or, if iIdxNoSeek is not a valid cursor number, the
+**   position of iDataCur should be preserved instead.
+**
+** iIdxNoSeek:
+**   If iIdxNoSeek is a valid cursor number (>=0) not equal to iDataCur,
+**   then it identifies an index cursor (from within array of cursors
+**   starting at iIdxCur) that already points to the index entry to be deleted.
+**   Except, this optimization is disabled if there are BEFORE triggers since
+**   the trigger body might have moved the cursor.
+*/
+SQLITE_PRIVATE void sqlite3GenerateRowDelete(
+  Parse *pParse,     /* Parsing context */
+  Table *pTab,       /* Table containing the row to be deleted */
+  Trigger *pTrigger, /* List of triggers to (potentially) fire */
+  int iDataCur,      /* Cursor from which column data is extracted */
+  int iIdxCur,       /* First index cursor */
+  int iPk,           /* First memory cell containing the PRIMARY KEY */
+  i16 nPk,           /* Number of PRIMARY KEY memory cells */
+  u8 count,          /* If non-zero, increment the row change counter */
+  u8 onconf,         /* Default ON CONFLICT policy for triggers */
+  u8 eMode,          /* ONEPASS_OFF, _SINGLE, or _MULTI.  See above */
+  int iIdxNoSeek     /* Cursor number of cursor that does not need seeking */
+){
+  Vdbe *v = pParse->pVdbe;        /* Vdbe */
+  int iOld = 0;                   /* First register in OLD.* array */
+  int iLabel;                     /* Label resolved to end of generated code */
+  u8 opSeek;                      /* Seek opcode */
+
+  /* Vdbe is guaranteed to have been allocated by this stage. */
+  assert( v );
+  VdbeModuleComment((v, "BEGIN: GenRowDel(%d,%d,%d,%d)",
+                         iDataCur, iIdxCur, iPk, (int)nPk));
+
+  /* Seek cursor iCur to the row to delete. If this row no longer exists
+  ** (this can happen if a trigger program has already deleted it), do
+  ** not attempt to delete it or fire any DELETE triggers.  */
+  iLabel = sqlite3VdbeMakeLabel(pParse);
+  opSeek = HasRowid(pTab) ? OP_NotExists : OP_NotFound;
+  if( eMode==ONEPASS_OFF ){
+    sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
+    VdbeCoverageIf(v, opSeek==OP_NotExists);
+    VdbeCoverageIf(v, opSeek==OP_NotFound);
+  }
+
+  /* If there are any triggers to fire, allocate a range of registers to
+  ** use for the old.* references in the triggers.  */
+  if( sqlite3FkRequired(pParse, pTab, 0, 0) || pTrigger ){
+    u32 mask;                     /* Mask of OLD.* columns in use */
+    int iCol;                     /* Iterator used while populating OLD.* */
+    int addrStart;                /* Start of BEFORE trigger programs */
+
+    /* TODO: Could use temporary registers here. Also could attempt to
+    ** avoid copying the contents of the rowid register.  */
+    mask = sqlite3TriggerColmask(
+        pParse, pTrigger, 0, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onconf
+    );
+    mask |= sqlite3FkOldmask(pParse, pTab);
+    iOld = pParse->nMem+1;
+    pParse->nMem += (1 + pTab->nCol);
+
+    /* Populate the OLD.* pseudo-table register array. These values will be
+    ** used by any BEFORE and AFTER triggers that exist.  */
+    sqlite3VdbeAddOp2(v, OP_Copy, iPk, iOld);
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      testcase( mask!=0xffffffff && iCol==31 );
+      testcase( mask!=0xffffffff && iCol==32 );
+      if( mask==0xffffffff || (iCol<=31 && (mask & MASKBIT32(iCol))!=0) ){
+        int kk = sqlite3TableColumnToStorage(pTab, iCol);
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, iCol, iOld+kk+1);
+      }
+    }
+
+    /* Invoke BEFORE DELETE trigger programs. */
+    addrStart = sqlite3VdbeCurrentAddr(v);
+    sqlite3CodeRowTrigger(pParse, pTrigger,
+        TK_DELETE, 0, TRIGGER_BEFORE, pTab, iOld, onconf, iLabel
+    );
+
+    /* If any BEFORE triggers were coded, then seek the cursor to the
+    ** row to be deleted again. It may be that the BEFORE triggers moved
+    ** the cursor or already deleted the row that the cursor was
+    ** pointing to.
+    **
+    ** Also disable the iIdxNoSeek optimization since the BEFORE trigger
+    ** may have moved that cursor.
+    */
+    if( addrStart<sqlite3VdbeCurrentAddr(v) ){
+      sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
+      VdbeCoverageIf(v, opSeek==OP_NotExists);
+      VdbeCoverageIf(v, opSeek==OP_NotFound);
+      testcase( iIdxNoSeek>=0 );
+      iIdxNoSeek = -1;
+    }
+
+    /* Do FK processing. This call checks that any FK constraints that
+    ** refer to this table (i.e. constraints attached to other tables)
+    ** are not violated by deleting this row.  */
+    sqlite3FkCheck(pParse, pTab, iOld, 0, 0, 0);
+  }
+
+  /* Delete the index and table entries. Skip this step if pTab is really
+  ** a view (in which case the only effect of the DELETE statement is to
+  ** fire the INSTEAD OF triggers).
+  **
+  ** If variable 'count' is non-zero, then this OP_Delete instruction should
+  ** invoke the update-hook. The pre-update-hook, on the other hand should
+  ** be invoked unless table pTab is a system table. The difference is that
+  ** the update-hook is not invoked for rows removed by REPLACE, but the
+  ** pre-update-hook is.
+  */
+  if( !IsView(pTab) ){
+    u8 p5 = 0;
+    sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,iIdxNoSeek);
+    sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, (count?OPFLAG_NCHANGE:0));
+    if( pParse->nested==0 || 0==sqlite3_stricmp(pTab->zName, "sqlite_stat1") ){
+      sqlite3VdbeAppendP4(v, (char*)pTab, P4_TABLE);
+    }
+    if( eMode!=ONEPASS_OFF ){
+      sqlite3VdbeChangeP5(v, OPFLAG_AUXDELETE);
+    }
+    if( iIdxNoSeek>=0 && iIdxNoSeek!=iDataCur ){
+      sqlite3VdbeAddOp1(v, OP_Delete, iIdxNoSeek);
+    }
+    if( eMode==ONEPASS_MULTI ) p5 |= OPFLAG_SAVEPOSITION;
+    sqlite3VdbeChangeP5(v, p5);
+  }
+
+  /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
+  ** handle rows (possibly in other tables) that refer via a foreign key
+  ** to the row just deleted. */
+  sqlite3FkActions(pParse, pTab, 0, iOld, 0, 0);
+
+  /* Invoke AFTER DELETE trigger programs. */
+  if( pTrigger ){
+    sqlite3CodeRowTrigger(pParse, pTrigger,
+        TK_DELETE, 0, TRIGGER_AFTER, pTab, iOld, onconf, iLabel
+    );
+  }
+
+  /* Jump here if the row had already been deleted before any BEFORE
+  ** trigger programs were invoked. Or if a trigger program throws a
+  ** RAISE(IGNORE) exception.  */
+  sqlite3VdbeResolveLabel(v, iLabel);
+  VdbeModuleComment((v, "END: GenRowDel()"));
+}
+
+/*
+** This routine generates VDBE code that causes the deletion of all
+** index entries associated with a single row of a single table, pTab
+**
+** Preconditions:
+**
+**   1.  A read/write cursor "iDataCur" must be open on the canonical storage
+**       btree for the table pTab.  (This will be either the table itself
+**       for rowid tables or to the primary key index for WITHOUT ROWID
+**       tables.)
+**
+**   2.  Read/write cursors for all indices of pTab must be open as
+**       cursor number iIdxCur+i for the i-th index.  (The pTab->pIndex
+**       index is the 0-th index.)
+**
+**   3.  The "iDataCur" cursor must be already be positioned on the row
+**       that is to be deleted.
+*/
+SQLITE_PRIVATE void sqlite3GenerateRowIndexDelete(
+  Parse *pParse,     /* Parsing and code generating context */
+  Table *pTab,       /* Table containing the row to be deleted */
+  int iDataCur,      /* Cursor of table holding data. */
+  int iIdxCur,       /* First index cursor */
+  int *aRegIdx,      /* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */
+  int iIdxNoSeek     /* Do not delete from this cursor */
+){
+  int i;             /* Index loop counter */
+  int r1 = -1;       /* Register holding an index key */
+  int iPartIdxLabel; /* Jump destination for skipping partial index entries */
+  Index *pIdx;       /* Current index */
+  Index *pPrior = 0; /* Prior index */
+  Vdbe *v;           /* The prepared statement under construction */
+  Index *pPk;        /* PRIMARY KEY index, or NULL for rowid tables */
+
+  v = pParse->pVdbe;
+  pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
+  for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
+    assert( iIdxCur+i!=iDataCur || pPk==pIdx );
+    if( aRegIdx!=0 && aRegIdx[i]==0 ) continue;
+    if( pIdx==pPk ) continue;
+    if( iIdxCur+i==iIdxNoSeek ) continue;
+    VdbeModuleComment((v, "GenRowIdxDel for %s", pIdx->zName));
+    r1 = sqlite3GenerateIndexKey(pParse, pIdx, iDataCur, 0, 1,
+        &iPartIdxLabel, pPrior, r1);
+    sqlite3VdbeAddOp3(v, OP_IdxDelete, iIdxCur+i, r1,
+        pIdx->uniqNotNull ? pIdx->nKeyCol : pIdx->nColumn);
+    sqlite3VdbeChangeP5(v, 1);  /* Cause IdxDelete to error if no entry found */
+    sqlite3ResolvePartIdxLabel(pParse, iPartIdxLabel);
+    pPrior = pIdx;
+  }
+}
+
+/*
+** Generate code that will assemble an index key and stores it in register
+** regOut.  The key with be for index pIdx which is an index on pTab.
+** iCur is the index of a cursor open on the pTab table and pointing to
+** the entry that needs indexing.  If pTab is a WITHOUT ROWID table, then
+** iCur must be the cursor of the PRIMARY KEY index.
+**
+** Return a register number which is the first in a block of
+** registers that holds the elements of the index key.  The
+** block of registers has already been deallocated by the time
+** this routine returns.
+**
+** If *piPartIdxLabel is not NULL, fill it in with a label and jump
+** to that label if pIdx is a partial index that should be skipped.
+** The label should be resolved using sqlite3ResolvePartIdxLabel().
+** A partial index should be skipped if its WHERE clause evaluates
+** to false or null.  If pIdx is not a partial index, *piPartIdxLabel
+** will be set to zero which is an empty label that is ignored by
+** sqlite3ResolvePartIdxLabel().
+**
+** The pPrior and regPrior parameters are used to implement a cache to
+** avoid unnecessary register loads.  If pPrior is not NULL, then it is
+** a pointer to a different index for which an index key has just been
+** computed into register regPrior.  If the current pIdx index is generating
+** its key into the same sequence of registers and if pPrior and pIdx share
+** a column in common, then the register corresponding to that column already
+** holds the correct value and the loading of that register is skipped.
+** This optimization is helpful when doing a DELETE or an INTEGRITY_CHECK
+** on a table with multiple indices, and especially with the ROWID or
+** PRIMARY KEY columns of the index.
+*/
+SQLITE_PRIVATE int sqlite3GenerateIndexKey(
+  Parse *pParse,       /* Parsing context */
+  Index *pIdx,         /* The index for which to generate a key */
+  int iDataCur,        /* Cursor number from which to take column data */
+  int regOut,          /* Put the new key into this register if not 0 */
+  int prefixOnly,      /* Compute only a unique prefix of the key */
+  int *piPartIdxLabel, /* OUT: Jump to this label to skip partial index */
+  Index *pPrior,       /* Previously generated index key */
+  int regPrior         /* Register holding previous generated key */
+){
+  Vdbe *v = pParse->pVdbe;
+  int j;
+  int regBase;
+  int nCol;
+
+  if( piPartIdxLabel ){
+    if( pIdx->pPartIdxWhere ){
+      *piPartIdxLabel = sqlite3VdbeMakeLabel(pParse);
+      pParse->iSelfTab = iDataCur + 1;
+      sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, *piPartIdxLabel,
+                            SQLITE_JUMPIFNULL);
+      pParse->iSelfTab = 0;
+      pPrior = 0; /* Ticket a9efb42811fa41ee 2019-11-02;
+                  ** pPartIdxWhere may have corrupted regPrior registers */
+    }else{
+      *piPartIdxLabel = 0;
+    }
+  }
+  nCol = (prefixOnly && pIdx->uniqNotNull) ? pIdx->nKeyCol : pIdx->nColumn;
+  regBase = sqlite3GetTempRange(pParse, nCol);
+  if( pPrior && (regBase!=regPrior || pPrior->pPartIdxWhere) ) pPrior = 0;
+  for(j=0; j<nCol; j++){
+    if( pPrior
+     && pPrior->aiColumn[j]==pIdx->aiColumn[j]
+     && pPrior->aiColumn[j]!=XN_EXPR
+    ){
+      /* This column was already computed by the previous index */
+      continue;
+    }
+    sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iDataCur, j, regBase+j);
+    if( pIdx->aiColumn[j]>=0 ){
+      /* If the column affinity is REAL but the number is an integer, then it
+      ** might be stored in the table as an integer (using a compact
+      ** representation) then converted to REAL by an OP_RealAffinity opcode.
+      ** But we are getting ready to store this value back into an index, where
+      ** it should be converted by to INTEGER again.  So omit the
+      ** OP_RealAffinity opcode if it is present */
+      sqlite3VdbeDeletePriorOpcode(v, OP_RealAffinity);
+    }
+  }
+  if( regOut ){
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regOut);
+  }
+  sqlite3ReleaseTempRange(pParse, regBase, nCol);
+  return regBase;
+}
+
+/*
+** If a prior call to sqlite3GenerateIndexKey() generated a jump-over label
+** because it was a partial index, then this routine should be called to
+** resolve that label.
+*/
+SQLITE_PRIVATE void sqlite3ResolvePartIdxLabel(Parse *pParse, int iLabel){
+  if( iLabel ){
+    sqlite3VdbeResolveLabel(pParse->pVdbe, iLabel);
+  }
+}
+
+/************** End of delete.c **********************************************/
+/************** Begin file func.c ********************************************/
+/*
+** 2002 February 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the C-language implementations for many of the SQL
+** functions of SQLite.  (Some function, and in particular the date and
+** time functions, are implemented separately.)
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdlib.h> */
+/* #include <assert.h> */
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/* #include <math.h> */
+#endif
+/* #include "vdbeInt.h" */
+
+/*
+** Return the collating function associated with a function.
+*/
+static CollSeq *sqlite3GetFuncCollSeq(sqlite3_context *context){
+  VdbeOp *pOp;
+  assert( context->pVdbe!=0 );
+  pOp = &context->pVdbe->aOp[context->iOp-1];
+  assert( pOp->opcode==OP_CollSeq );
+  assert( pOp->p4type==P4_COLLSEQ );
+  return pOp->p4.pColl;
+}
+
+/*
+** Indicate that the accumulator load should be skipped on this
+** iteration of the aggregate loop.
+*/
+static void sqlite3SkipAccumulatorLoad(sqlite3_context *context){
+  assert( context->isError<=0 );
+  context->isError = -1;
+  context->skipFlag = 1;
+}
+
+/*
+** Implementation of the non-aggregate min() and max() functions
+*/
+static void minmaxFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+  int mask;    /* 0 for min() or 0xffffffff for max() */
+  int iBest;
+  CollSeq *pColl;
+
+  assert( argc>1 );
+  mask = sqlite3_user_data(context)==0 ? 0 : -1;
+  pColl = sqlite3GetFuncCollSeq(context);
+  assert( pColl );
+  assert( mask==-1 || mask==0 );
+  iBest = 0;
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  for(i=1; i<argc; i++){
+    if( sqlite3_value_type(argv[i])==SQLITE_NULL ) return;
+    if( (sqlite3MemCompare(argv[iBest], argv[i], pColl)^mask)>=0 ){
+      testcase( mask==0 );
+      iBest = i;
+    }
+  }
+  sqlite3_result_value(context, argv[iBest]);
+}
+
+/*
+** Return the type of the argument.
+*/
+static void typeofFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  static const char *azType[] = { "integer", "real", "text", "blob", "null" };
+  int i = sqlite3_value_type(argv[0]) - 1;
+  UNUSED_PARAMETER(NotUsed);
+  assert( i>=0 && i<ArraySize(azType) );
+  assert( SQLITE_INTEGER==1 );
+  assert( SQLITE_FLOAT==2 );
+  assert( SQLITE_TEXT==3 );
+  assert( SQLITE_BLOB==4 );
+  assert( SQLITE_NULL==5 );
+  /* EVIDENCE-OF: R-01470-60482 The sqlite3_value_type(V) interface returns
+  ** the datatype code for the initial datatype of the sqlite3_value object
+  ** V. The returned value is one of SQLITE_INTEGER, SQLITE_FLOAT,
+  ** SQLITE_TEXT, SQLITE_BLOB, or SQLITE_NULL. */
+  sqlite3_result_text(context, azType[i], -1, SQLITE_STATIC);
+}
+
+/* subtype(X)
+**
+** Return the subtype of X
+*/
+static void subtypeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  UNUSED_PARAMETER(argc);
+  sqlite3_result_int(context, sqlite3_value_subtype(argv[0]));
+}
+
+/*
+** Implementation of the length() function
+*/
+static void lengthFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_BLOB:
+    case SQLITE_INTEGER:
+    case SQLITE_FLOAT: {
+      sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
+      break;
+    }
+    case SQLITE_TEXT: {
+      const unsigned char *z = sqlite3_value_text(argv[0]);
+      const unsigned char *z0;
+      unsigned char c;
+      if( z==0 ) return;
+      z0 = z;
+      while( (c = *z)!=0 ){
+        z++;
+        if( c>=0xc0 ){
+          while( (*z & 0xc0)==0x80 ){ z++; z0++; }
+        }
+      }
+      sqlite3_result_int(context, (int)(z-z0));
+      break;
+    }
+    default: {
+      sqlite3_result_null(context);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the octet_length() function
+*/
+static void bytelengthFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_BLOB: {
+      sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
+      break;
+    }
+    case SQLITE_INTEGER:
+    case SQLITE_FLOAT: {
+      i64 m = sqlite3_context_db_handle(context)->enc<=SQLITE_UTF8 ? 1 : 2;
+      sqlite3_result_int64(context, sqlite3_value_bytes(argv[0])*m);
+      break;
+    }
+    case SQLITE_TEXT: {
+      if( sqlite3_value_encoding(argv[0])<=SQLITE_UTF8 ){
+        sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
+      }else{
+        sqlite3_result_int(context, sqlite3_value_bytes16(argv[0]));
+      }
+      break;
+    }
+    default: {
+      sqlite3_result_null(context);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the abs() function.
+**
+** IMP: R-23979-26855 The abs(X) function returns the absolute value of
+** the numeric argument X.
+*/
+static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_INTEGER: {
+      i64 iVal = sqlite3_value_int64(argv[0]);
+      if( iVal<0 ){
+        if( iVal==SMALLEST_INT64 ){
+          /* IMP: R-31676-45509 If X is the integer -9223372036854775808
+          ** then abs(X) throws an integer overflow error since there is no
+          ** equivalent positive 64-bit two complement value. */
+          sqlite3_result_error(context, "integer overflow", -1);
+          return;
+        }
+        iVal = -iVal;
+      }
+      sqlite3_result_int64(context, iVal);
+      break;
+    }
+    case SQLITE_NULL: {
+      /* IMP: R-37434-19929 Abs(X) returns NULL if X is NULL. */
+      sqlite3_result_null(context);
+      break;
+    }
+    default: {
+      /* Because sqlite3_value_double() returns 0.0 if the argument is not
+      ** something that can be converted into a number, we have:
+      ** IMP: R-01992-00519 Abs(X) returns 0.0 if X is a string or blob
+      ** that cannot be converted to a numeric value.
+      */
+      double rVal = sqlite3_value_double(argv[0]);
+      if( rVal<0 ) rVal = -rVal;
+      sqlite3_result_double(context, rVal);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the instr() function.
+**
+** instr(haystack,needle) finds the first occurrence of needle
+** in haystack and returns the number of previous characters plus 1,
+** or 0 if needle does not occur within haystack.
+**
+** If both haystack and needle are BLOBs, then the result is one more than
+** the number of bytes in haystack prior to the first occurrence of needle,
+** or 0 if needle never occurs in haystack.
+*/
+static void instrFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zHaystack;
+  const unsigned char *zNeedle;
+  int nHaystack;
+  int nNeedle;
+  int typeHaystack, typeNeedle;
+  int N = 1;
+  int isText;
+  unsigned char firstChar;
+  sqlite3_value *pC1 = 0;
+  sqlite3_value *pC2 = 0;
+
+  UNUSED_PARAMETER(argc);
+  typeHaystack = sqlite3_value_type(argv[0]);
+  typeNeedle = sqlite3_value_type(argv[1]);
+  if( typeHaystack==SQLITE_NULL || typeNeedle==SQLITE_NULL ) return;
+  nHaystack = sqlite3_value_bytes(argv[0]);
+  nNeedle = sqlite3_value_bytes(argv[1]);
+  if( nNeedle>0 ){
+    if( typeHaystack==SQLITE_BLOB && typeNeedle==SQLITE_BLOB ){
+      zHaystack = sqlite3_value_blob(argv[0]);
+      zNeedle = sqlite3_value_blob(argv[1]);
+      isText = 0;
+    }else if( typeHaystack!=SQLITE_BLOB && typeNeedle!=SQLITE_BLOB ){
+      zHaystack = sqlite3_value_text(argv[0]);
+      zNeedle = sqlite3_value_text(argv[1]);
+      isText = 1;
+    }else{
+      pC1 = sqlite3_value_dup(argv[0]);
+      zHaystack = sqlite3_value_text(pC1);
+      if( zHaystack==0 ) goto endInstrOOM;
+      nHaystack = sqlite3_value_bytes(pC1);
+      pC2 = sqlite3_value_dup(argv[1]);
+      zNeedle = sqlite3_value_text(pC2);
+      if( zNeedle==0 ) goto endInstrOOM;
+      nNeedle = sqlite3_value_bytes(pC2);
+      isText = 1;
+    }
+    if( zNeedle==0 || (nHaystack && zHaystack==0) ) goto endInstrOOM;
+    firstChar = zNeedle[0];
+    while( nNeedle<=nHaystack
+       && (zHaystack[0]!=firstChar || memcmp(zHaystack, zNeedle, nNeedle)!=0)
+    ){
+      N++;
+      do{
+        nHaystack--;
+        zHaystack++;
+      }while( isText && (zHaystack[0]&0xc0)==0x80 );
+    }
+    if( nNeedle>nHaystack ) N = 0;
+  }
+  sqlite3_result_int(context, N);
+endInstr:
+  sqlite3_value_free(pC1);
+  sqlite3_value_free(pC2);
+  return;
+endInstrOOM:
+  sqlite3_result_error_nomem(context);
+  goto endInstr;
+}
+
+/*
+** Implementation of the printf() (a.k.a. format()) SQL function.
+*/
+static void printfFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  PrintfArguments x;
+  StrAccum str;
+  const char *zFormat;
+  int n;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+
+  if( argc>=1 && (zFormat = (const char*)sqlite3_value_text(argv[0]))!=0 ){
+    x.nArg = argc-1;
+    x.nUsed = 0;
+    x.apArg = argv+1;
+    sqlite3StrAccumInit(&str, db, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
+    str.printfFlags = SQLITE_PRINTF_SQLFUNC;
+    sqlite3_str_appendf(&str, zFormat, &x);
+    n = str.nChar;
+    sqlite3_result_text(context, sqlite3StrAccumFinish(&str), n,
+                        SQLITE_DYNAMIC);
+  }
+}
+
+/*
+** Implementation of the substr() function.
+**
+** substr(x,p1,p2)  returns p2 characters of x[] beginning with p1.
+** p1 is 1-indexed.  So substr(x,1,1) returns the first character
+** of x.  If x is text, then we actually count UTF-8 characters.
+** If x is a blob, then we count bytes.
+**
+** If p1 is negative, then we begin abs(p1) from the end of x[].
+**
+** If p2 is negative, return the p2 characters preceding p1.
+*/
+static void substrFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *z;
+  const unsigned char *z2;
+  int len;
+  int p0type;
+  i64 p1, p2;
+
+  assert( argc==3 || argc==2 );
+  if( sqlite3_value_type(argv[1])==SQLITE_NULL
+   || (argc==3 && sqlite3_value_type(argv[2])==SQLITE_NULL)
+  ){
+    return;
+  }
+  p0type = sqlite3_value_type(argv[0]);
+  p1 = sqlite3_value_int64(argv[1]);
+  if( p0type==SQLITE_BLOB ){
+    len = sqlite3_value_bytes(argv[0]);
+    z = sqlite3_value_blob(argv[0]);
+    if( z==0 ) return;
+    assert( len==sqlite3_value_bytes(argv[0]) );
+  }else{
+    z = sqlite3_value_text(argv[0]);
+    if( z==0 ) return;
+    len = 0;
+    if( p1<0 ){
+      for(z2=z; *z2; len++){
+        SQLITE_SKIP_UTF8(z2);
+      }
+    }
+  }
+#ifdef SQLITE_SUBSTR_COMPATIBILITY
+  /* If SUBSTR_COMPATIBILITY is defined then substr(X,0,N) work the same as
+  ** as substr(X,1,N) - it returns the first N characters of X.  This
+  ** is essentially a back-out of the bug-fix in check-in [5fc125d362df4b8]
+  ** from 2009-02-02 for compatibility of applications that exploited the
+  ** old buggy behavior. */
+  if( p1==0 ) p1 = 1; /* <rdar://problem/6778339> */
+#endif
+  if( argc==3 ){
+    p2 = sqlite3_value_int64(argv[2]);
+  }else{
+    p2 = sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH];
+  }
+  if( p1<0 ){
+    p1 += len;
+    if( p1<0 ){
+      if( p2<0 ){
+        p2 = 0;
+      }else{
+        p2 += p1;
+      }
+      p1 = 0;
+    }
+  }else if( p1>0 ){
+    p1--;
+  }else if( p2>0 ){
+    p2--;
+  }
+  if( p2<0 ){
+    if( p2<-p1 ){
+      p2 = p1;
+    }else{
+      p2 = -p2;
+    }
+    p1 -= p2;
+  }
+  assert( p1>=0 && p2>=0 );
+  if( p0type!=SQLITE_BLOB ){
+    while( *z && p1 ){
+      SQLITE_SKIP_UTF8(z);
+      p1--;
+    }
+    for(z2=z; *z2 && p2; p2--){
+      SQLITE_SKIP_UTF8(z2);
+    }
+    sqlite3_result_text64(context, (char*)z, z2-z, SQLITE_TRANSIENT,
+                          SQLITE_UTF8);
+  }else{
+    if( p1>=len ){
+      p1 = p2 = 0;
+    }else if( p2>len-p1 ){
+      p2 = len-p1;
+      assert( p2>0 );
+    }
+    sqlite3_result_blob64(context, (char*)&z[p1], (u64)p2, SQLITE_TRANSIENT);
+  }
+}
+
+/*
+** Implementation of the round() function
+*/
+#ifndef SQLITE_OMIT_FLOATING_POINT
+static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  i64 n = 0;
+  double r;
+  char *zBuf;
+  assert( argc==1 || argc==2 );
+  if( argc==2 ){
+    if( SQLITE_NULL==sqlite3_value_type(argv[1]) ) return;
+    n = sqlite3_value_int64(argv[1]);
+    if( n>30 ) n = 30;
+    if( n<0 ) n = 0;
+  }
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  r = sqlite3_value_double(argv[0]);
+  /* If Y==0 and X will fit in a 64-bit int,
+  ** handle the rounding directly,
+  ** otherwise use printf.
+  */
+  if( r<-4503599627370496.0 || r>+4503599627370496.0 ){
+    /* The value has no fractional part so there is nothing to round */
+  }else if( n==0 ){
+    r = (double)((sqlite_int64)(r+(r<0?-0.5:+0.5)));
+  }else{
+    zBuf = sqlite3_mprintf("%!.*f",(int)n,r);
+    if( zBuf==0 ){
+      sqlite3_result_error_nomem(context);
+      return;
+    }
+    sqlite3AtoF(zBuf, &r, sqlite3Strlen30(zBuf), SQLITE_UTF8);
+    sqlite3_free(zBuf);
+  }
+  sqlite3_result_double(context, r);
+}
+#endif
+
+/*
+** Allocate nByte bytes of space using sqlite3Malloc(). If the
+** allocation fails, call sqlite3_result_error_nomem() to notify
+** the database handle that malloc() has failed and return NULL.
+** If nByte is larger than the maximum string or blob length, then
+** raise an SQLITE_TOOBIG exception and return NULL.
+*/
+static void *contextMalloc(sqlite3_context *context, i64 nByte){
+  char *z;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  assert( nByte>0 );
+  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH] );
+  testcase( nByte==db->aLimit[SQLITE_LIMIT_LENGTH]+1 );
+  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    sqlite3_result_error_toobig(context);
+    z = 0;
+  }else{
+    z = sqlite3Malloc(nByte);
+    if( !z ){
+      sqlite3_result_error_nomem(context);
+    }
+  }
+  return z;
+}
+
+/*
+** Implementation of the upper() and lower() SQL functions.
+*/
+static void upperFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  char *z1;
+  const char *z2;
+  int i, n;
+  UNUSED_PARAMETER(argc);
+  z2 = (char*)sqlite3_value_text(argv[0]);
+  n = sqlite3_value_bytes(argv[0]);
+  /* Verify that the call to _bytes() does not invalidate the _text() pointer */
+  assert( z2==(char*)sqlite3_value_text(argv[0]) );
+  if( z2 ){
+    z1 = contextMalloc(context, ((i64)n)+1);
+    if( z1 ){
+      for(i=0; i<n; i++){
+        z1[i] = (char)sqlite3Toupper(z2[i]);
+      }
+      sqlite3_result_text(context, z1, n, sqlite3_free);
+    }
+  }
+}
+static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  char *z1;
+  const char *z2;
+  int i, n;
+  UNUSED_PARAMETER(argc);
+  z2 = (char*)sqlite3_value_text(argv[0]);
+  n = sqlite3_value_bytes(argv[0]);
+  /* Verify that the call to _bytes() does not invalidate the _text() pointer */
+  assert( z2==(char*)sqlite3_value_text(argv[0]) );
+  if( z2 ){
+    z1 = contextMalloc(context, ((i64)n)+1);
+    if( z1 ){
+      for(i=0; i<n; i++){
+        z1[i] = sqlite3Tolower(z2[i]);
+      }
+      sqlite3_result_text(context, z1, n, sqlite3_free);
+    }
+  }
+}
+
+/*
+** Some functions like COALESCE() and IFNULL() and UNLIKELY() are implemented
+** as VDBE code so that unused argument values do not have to be computed.
+** However, we still need some kind of function implementation for this
+** routines in the function table.  The noopFunc macro provides this.
+** noopFunc will never be called so it doesn't matter what the implementation
+** is.  We might as well use the "version()" function as a substitute.
+*/
+#define noopFunc versionFunc   /* Substitute function - never called */
+
+/*
+** Implementation of random().  Return a random integer.
+*/
+static void randomFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  sqlite_int64 r;
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  sqlite3_randomness(sizeof(r), &r);
+  if( r<0 ){
+    /* We need to prevent a random number of 0x8000000000000000
+    ** (or -9223372036854775808) since when you do abs() of that
+    ** number of you get the same value back again.  To do this
+    ** in a way that is testable, mask the sign bit off of negative
+    ** values, resulting in a positive value.  Then take the
+    ** 2s complement of that positive value.  The end result can
+    ** therefore be no less than -9223372036854775807.
+    */
+    r = -(r & LARGEST_INT64);
+  }
+  sqlite3_result_int64(context, r);
+}
+
+/*
+** Implementation of randomblob(N).  Return a random blob
+** that is N bytes long.
+*/
+static void randomBlob(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_int64 n;
+  unsigned char *p;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  n = sqlite3_value_int64(argv[0]);
+  if( n<1 ){
+    n = 1;
+  }
+  p = contextMalloc(context, n);
+  if( p ){
+    sqlite3_randomness(n, p);
+    sqlite3_result_blob(context, (char*)p, n, sqlite3_free);
+  }
+}
+
+/*
+** Implementation of the last_insert_rowid() SQL function.  The return
+** value is the same as the sqlite3_last_insert_rowid() API function.
+*/
+static void last_insert_rowid(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-51513-12026 The last_insert_rowid() SQL function is a
+  ** wrapper around the sqlite3_last_insert_rowid() C/C++ interface
+  ** function. */
+  sqlite3_result_int64(context, sqlite3_last_insert_rowid(db));
+}
+
+/*
+** Implementation of the changes() SQL function.
+**
+** IMP: R-32760-32347 The changes() SQL function is a wrapper
+** around the sqlite3_changes64() C/C++ function and hence follows the
+** same rules for counting changes.
+*/
+static void changes(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  sqlite3_result_int64(context, sqlite3_changes64(db));
+}
+
+/*
+** Implementation of the total_changes() SQL function.  The return value is
+** the same as the sqlite3_total_changes64() API function.
+*/
+static void total_changes(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-11217-42568 This function is a wrapper around the
+  ** sqlite3_total_changes64() C/C++ interface. */
+  sqlite3_result_int64(context, sqlite3_total_changes64(db));
+}
+
+/*
+** A structure defining how to do GLOB-style comparisons.
+*/
+struct compareInfo {
+  u8 matchAll;          /* "*" or "%" */
+  u8 matchOne;          /* "?" or "_" */
+  u8 matchSet;          /* "[" or 0 */
+  u8 noCase;            /* true to ignore case differences */
+};
+
+/*
+** For LIKE and GLOB matching on EBCDIC machines, assume that every
+** character is exactly one byte in size.  Also, provide the Utf8Read()
+** macro for fast reading of the next character in the common case where
+** the next character is ASCII.
+*/
+#if defined(SQLITE_EBCDIC)
+# define sqlite3Utf8Read(A)        (*((*A)++))
+# define Utf8Read(A)               (*(A++))
+#else
+# define Utf8Read(A)               (A[0]<0x80?*(A++):sqlite3Utf8Read(&A))
+#endif
+
+static const struct compareInfo globInfo = { '*', '?', '[', 0 };
+/* The correct SQL-92 behavior is for the LIKE operator to ignore
+** case.  Thus  'a' LIKE 'A' would be true. */
+static const struct compareInfo likeInfoNorm = { '%', '_',   0, 1 };
+/* If SQLITE_CASE_SENSITIVE_LIKE is defined, then the LIKE operator
+** is case sensitive causing 'a' LIKE 'A' to be false */
+static const struct compareInfo likeInfoAlt = { '%', '_',   0, 0 };
+
+/*
+** Possible error returns from patternMatch()
+*/
+#define SQLITE_MATCH             0
+#define SQLITE_NOMATCH           1
+#define SQLITE_NOWILDCARDMATCH   2
+
+/*
+** Compare two UTF-8 strings for equality where the first string is
+** a GLOB or LIKE expression.  Return values:
+**
+**    SQLITE_MATCH:            Match
+**    SQLITE_NOMATCH:          No match
+**    SQLITE_NOWILDCARDMATCH:  No match in spite of having * or % wildcards.
+**
+** Globbing rules:
+**
+**      '*'       Matches any sequence of zero or more characters.
+**
+**      '?'       Matches exactly one character.
+**
+**     [...]      Matches one character from the enclosed list of
+**                characters.
+**
+**     [^...]     Matches one character not in the enclosed list.
+**
+** With the [...] and [^...] matching, a ']' character can be included
+** in the list by making it the first character after '[' or '^'.  A
+** range of characters can be specified using '-'.  Example:
+** "[a-z]" matches any single lower-case letter.  To match a '-', make
+** it the last character in the list.
+**
+** Like matching rules:
+**
+**      '%'       Matches any sequence of zero or more characters
+**
+***     '_'       Matches any one character
+**
+**      Ec        Where E is the "esc" character and c is any other
+**                character, including '%', '_', and esc, match exactly c.
+**
+** The comments within this routine usually assume glob matching.
+**
+** This routine is usually quick, but can be N**2 in the worst case.
+*/
+static int patternCompare(
+  const u8 *zPattern,              /* The glob pattern */
+  const u8 *zString,               /* The string to compare against the glob */
+  const struct compareInfo *pInfo, /* Information about how to do the compare */
+  u32 matchOther                   /* The escape char (LIKE) or '[' (GLOB) */
+){
+  u32 c, c2;                       /* Next pattern and input string chars */
+  u32 matchOne = pInfo->matchOne;  /* "?" or "_" */
+  u32 matchAll = pInfo->matchAll;  /* "*" or "%" */
+  u8 noCase = pInfo->noCase;       /* True if uppercase==lowercase */
+  const u8 *zEscaped = 0;          /* One past the last escaped input char */
+
+  while( (c = Utf8Read(zPattern))!=0 ){
+    if( c==matchAll ){  /* Match "*" */
+      /* Skip over multiple "*" characters in the pattern.  If there
+      ** are also "?" characters, skip those as well, but consume a
+      ** single character of the input string for each "?" skipped */
+      while( (c=Utf8Read(zPattern)) == matchAll
+             || (c == matchOne && matchOne!=0) ){
+        if( c==matchOne && sqlite3Utf8Read(&zString)==0 ){
+          return SQLITE_NOWILDCARDMATCH;
+        }
+      }
+      if( c==0 ){
+        return SQLITE_MATCH;   /* "*" at the end of the pattern matches */
+      }else if( c==matchOther ){
+        if( pInfo->matchSet==0 ){
+          c = sqlite3Utf8Read(&zPattern);
+          if( c==0 ) return SQLITE_NOWILDCARDMATCH;
+        }else{
+          /* "[...]" immediately follows the "*".  We have to do a slow
+          ** recursive search in this case, but it is an unusual case. */
+          assert( matchOther<0x80 );  /* '[' is a single-byte character */
+          while( *zString ){
+            int bMatch = patternCompare(&zPattern[-1],zString,pInfo,matchOther);
+            if( bMatch!=SQLITE_NOMATCH ) return bMatch;
+            SQLITE_SKIP_UTF8(zString);
+          }
+          return SQLITE_NOWILDCARDMATCH;
+        }
+      }
+
+      /* At this point variable c contains the first character of the
+      ** pattern string past the "*".  Search in the input string for the
+      ** first matching character and recursively continue the match from
+      ** that point.
+      **
+      ** For a case-insensitive search, set variable cx to be the same as
+      ** c but in the other case and search the input string for either
+      ** c or cx.
+      */
+      if( c<0x80 ){
+        char zStop[3];
+        int bMatch;
+        if( noCase ){
+          zStop[0] = sqlite3Toupper(c);
+          zStop[1] = sqlite3Tolower(c);
+          zStop[2] = 0;
+        }else{
+          zStop[0] = c;
+          zStop[1] = 0;
+        }
+        while(1){
+          zString += strcspn((const char*)zString, zStop);
+          if( zString[0]==0 ) break;
+          zString++;
+          bMatch = patternCompare(zPattern,zString,pInfo,matchOther);
+          if( bMatch!=SQLITE_NOMATCH ) return bMatch;
+        }
+      }else{
+        int bMatch;
+        while( (c2 = Utf8Read(zString))!=0 ){
+          if( c2!=c ) continue;
+          bMatch = patternCompare(zPattern,zString,pInfo,matchOther);
+          if( bMatch!=SQLITE_NOMATCH ) return bMatch;
+        }
+      }
+      return SQLITE_NOWILDCARDMATCH;
+    }
+    if( c==matchOther ){
+      if( pInfo->matchSet==0 ){
+        c = sqlite3Utf8Read(&zPattern);
+        if( c==0 ) return SQLITE_NOMATCH;
+        zEscaped = zPattern;
+      }else{
+        u32 prior_c = 0;
+        int seen = 0;
+        int invert = 0;
+        c = sqlite3Utf8Read(&zString);
+        if( c==0 ) return SQLITE_NOMATCH;
+        c2 = sqlite3Utf8Read(&zPattern);
+        if( c2=='^' ){
+          invert = 1;
+          c2 = sqlite3Utf8Read(&zPattern);
+        }
+        if( c2==']' ){
+          if( c==']' ) seen = 1;
+          c2 = sqlite3Utf8Read(&zPattern);
+        }
+        while( c2 && c2!=']' ){
+          if( c2=='-' && zPattern[0]!=']' && zPattern[0]!=0 && prior_c>0 ){
+            c2 = sqlite3Utf8Read(&zPattern);
+            if( c>=prior_c && c<=c2 ) seen = 1;
+            prior_c = 0;
+          }else{
+            if( c==c2 ){
+              seen = 1;
+            }
+            prior_c = c2;
+          }
+          c2 = sqlite3Utf8Read(&zPattern);
+        }
+        if( c2==0 || (seen ^ invert)==0 ){
+          return SQLITE_NOMATCH;
+        }
+        continue;
+      }
+    }
+    c2 = Utf8Read(zString);
+    if( c==c2 ) continue;
+    if( noCase  && sqlite3Tolower(c)==sqlite3Tolower(c2) && c<0x80 && c2<0x80 ){
+      continue;
+    }
+    if( c==matchOne && zPattern!=zEscaped && c2!=0 ) continue;
+    return SQLITE_NOMATCH;
+  }
+  return *zString==0 ? SQLITE_MATCH : SQLITE_NOMATCH;
+}
+
+/*
+** The sqlite3_strglob() interface.  Return 0 on a match (like strcmp()) and
+** non-zero if there is no match.
+*/
+SQLITE_API int sqlite3_strglob(const char *zGlobPattern, const char *zString){
+  if( zString==0 ){
+    return zGlobPattern!=0;
+  }else if( zGlobPattern==0 ){
+    return 1;
+  }else {
+    return patternCompare((u8*)zGlobPattern, (u8*)zString, &globInfo, '[');
+  }
+}
+
+/*
+** The sqlite3_strlike() interface.  Return 0 on a match and non-zero for
+** a miss - like strcmp().
+*/
+SQLITE_API int sqlite3_strlike(const char *zPattern, const char *zStr, unsigned int esc){
+  if( zStr==0 ){
+    return zPattern!=0;
+  }else if( zPattern==0 ){
+    return 1;
+  }else{
+    return patternCompare((u8*)zPattern, (u8*)zStr, &likeInfoNorm, esc);
+  }
+}
+
+/*
+** Count the number of times that the LIKE operator (or GLOB which is
+** just a variation of LIKE) gets called.  This is used for testing
+** only.
+*/
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_like_count = 0;
+#endif
+
+
+/*
+** Implementation of the like() SQL function.  This function implements
+** the built-in LIKE operator.  The first argument to the function is the
+** pattern and the second argument is the string.  So, the SQL statements:
+**
+**       A LIKE B
+**
+** is implemented as like(B,A).
+**
+** This same function (with a different compareInfo structure) computes
+** the GLOB operator.
+*/
+static void likeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zA, *zB;
+  u32 escape;
+  int nPat;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  struct compareInfo *pInfo = sqlite3_user_data(context);
+  struct compareInfo backupInfo;
+
+#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+  if( sqlite3_value_type(argv[0])==SQLITE_BLOB
+   || sqlite3_value_type(argv[1])==SQLITE_BLOB
+  ){
+#ifdef SQLITE_TEST
+    sqlite3_like_count++;
+#endif
+    sqlite3_result_int(context, 0);
+    return;
+  }
+#endif
+
+  /* Limit the length of the LIKE or GLOB pattern to avoid problems
+  ** of deep recursion and N*N behavior in patternCompare().
+  */
+  nPat = sqlite3_value_bytes(argv[0]);
+  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] );
+  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]+1 );
+  if( nPat > db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] ){
+    sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
+    return;
+  }
+  if( argc==3 ){
+    /* The escape character string must consist of a single UTF-8 character.
+    ** Otherwise, return an error.
+    */
+    const unsigned char *zEsc = sqlite3_value_text(argv[2]);
+    if( zEsc==0 ) return;
+    if( sqlite3Utf8CharLen((char*)zEsc, -1)!=1 ){
+      sqlite3_result_error(context,
+          "ESCAPE expression must be a single character", -1);
+      return;
+    }
+    escape = sqlite3Utf8Read(&zEsc);
+    if( escape==pInfo->matchAll || escape==pInfo->matchOne ){
+      memcpy(&backupInfo, pInfo, sizeof(backupInfo));
+      pInfo = &backupInfo;
+      if( escape==pInfo->matchAll ) pInfo->matchAll = 0;
+      if( escape==pInfo->matchOne ) pInfo->matchOne = 0;
+    }
+  }else{
+    escape = pInfo->matchSet;
+  }
+  zB = sqlite3_value_text(argv[0]);
+  zA = sqlite3_value_text(argv[1]);
+  if( zA && zB ){
+#ifdef SQLITE_TEST
+    sqlite3_like_count++;
+#endif
+    sqlite3_result_int(context,
+                      patternCompare(zB, zA, pInfo, escape)==SQLITE_MATCH);
+  }
+}
+
+/*
+** Implementation of the NULLIF(x,y) function.  The result is the first
+** argument if the arguments are different.  The result is NULL if the
+** arguments are equal to each other.
+*/
+static void nullifFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  CollSeq *pColl = sqlite3GetFuncCollSeq(context);
+  UNUSED_PARAMETER(NotUsed);
+  if( sqlite3MemCompare(argv[0], argv[1], pColl)!=0 ){
+    sqlite3_result_value(context, argv[0]);
+  }
+}
+
+/*
+** Implementation of the sqlite_version() function.  The result is the version
+** of the SQLite library that is running.
+*/
+static void versionFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-48699-48617 This function is an SQL wrapper around the
+  ** sqlite3_libversion() C-interface. */
+  sqlite3_result_text(context, sqlite3_libversion(), -1, SQLITE_STATIC);
+}
+
+/*
+** Implementation of the sqlite_source_id() function. The result is a string
+** that identifies the particular version of the source code used to build
+** SQLite.
+*/
+static void sourceidFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **NotUsed2
+){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  /* IMP: R-24470-31136 This function is an SQL wrapper around the
+  ** sqlite3_sourceid() C interface. */
+  sqlite3_result_text(context, sqlite3_sourceid(), -1, SQLITE_STATIC);
+}
+
+/*
+** Implementation of the sqlite_log() function.  This is a wrapper around
+** sqlite3_log().  The return value is NULL.  The function exists purely for
+** its side-effects.
+*/
+static void errlogFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(context);
+  sqlite3_log(sqlite3_value_int(argv[0]), "%s", sqlite3_value_text(argv[1]));
+}
+
+/*
+** Implementation of the sqlite_compileoption_used() function.
+** The result is an integer that identifies if the compiler option
+** was used to build SQLite.
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+static void compileoptionusedFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *zOptName;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  /* IMP: R-39564-36305 The sqlite_compileoption_used() SQL
+  ** function is a wrapper around the sqlite3_compileoption_used() C/C++
+  ** function.
+  */
+  if( (zOptName = (const char*)sqlite3_value_text(argv[0]))!=0 ){
+    sqlite3_result_int(context, sqlite3_compileoption_used(zOptName));
+  }
+}
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/*
+** Implementation of the sqlite_compileoption_get() function.
+** The result is a string that identifies the compiler options
+** used to build SQLite.
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+static void compileoptiongetFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int n;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  /* IMP: R-04922-24076 The sqlite_compileoption_get() SQL function
+  ** is a wrapper around the sqlite3_compileoption_get() C/C++ function.
+  */
+  n = sqlite3_value_int(argv[0]);
+  sqlite3_result_text(context, sqlite3_compileoption_get(n), -1, SQLITE_STATIC);
+}
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/* Array for converting from half-bytes (nybbles) into ASCII hex
+** digits. */
+static const char hexdigits[] = {
+  '0', '1', '2', '3', '4', '5', '6', '7',
+  '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+};
+
+/*
+** Append to pStr text that is the SQL literal representation of the
+** value contained in pValue.
+*/
+SQLITE_PRIVATE void sqlite3QuoteValue(StrAccum *pStr, sqlite3_value *pValue){
+  /* As currently implemented, the string must be initially empty.
+  ** we might relax this requirement in the future, but that will
+  ** require enhancements to the implementation. */
+  assert( pStr!=0 && pStr->nChar==0 );
+
+  switch( sqlite3_value_type(pValue) ){
+    case SQLITE_FLOAT: {
+      double r1, r2;
+      const char *zVal;
+      r1 = sqlite3_value_double(pValue);
+      sqlite3_str_appendf(pStr, "%!0.15g", r1);
+      zVal = sqlite3_str_value(pStr);
+      if( zVal ){
+        sqlite3AtoF(zVal, &r2, pStr->nChar, SQLITE_UTF8);
+        if( r1!=r2 ){
+          sqlite3_str_reset(pStr);
+          sqlite3_str_appendf(pStr, "%!0.20e", r1);
+        }
+      }
+      break;
+    }
+    case SQLITE_INTEGER: {
+      sqlite3_str_appendf(pStr, "%lld", sqlite3_value_int64(pValue));
+      break;
+    }
+    case SQLITE_BLOB: {
+      char const *zBlob = sqlite3_value_blob(pValue);
+      i64 nBlob = sqlite3_value_bytes(pValue);
+      assert( zBlob==sqlite3_value_blob(pValue) ); /* No encoding change */
+      sqlite3StrAccumEnlarge(pStr, nBlob*2 + 4);
+      if( pStr->accError==0 ){
+        char *zText = pStr->zText;
+        int i;
+        for(i=0; i<nBlob; i++){
+          zText[(i*2)+2] = hexdigits[(zBlob[i]>>4)&0x0F];
+          zText[(i*2)+3] = hexdigits[(zBlob[i])&0x0F];
+        }
+        zText[(nBlob*2)+2] = '\'';
+        zText[(nBlob*2)+3] = '\0';
+        zText[0] = 'X';
+        zText[1] = '\'';
+        pStr->nChar = nBlob*2 + 3;
+      }
+      break;
+    }
+    case SQLITE_TEXT: {
+      const unsigned char *zArg = sqlite3_value_text(pValue);
+      sqlite3_str_appendf(pStr, "%Q", zArg);
+      break;
+    }
+    default: {
+      assert( sqlite3_value_type(pValue)==SQLITE_NULL );
+      sqlite3_str_append(pStr, "NULL", 4);
+      break;
+    }
+  }
+}
+
+/*
+** Implementation of the QUOTE() function.
+**
+** The quote(X) function returns the text of an SQL literal which is the
+** value of its argument suitable for inclusion into an SQL statement.
+** Strings are surrounded by single-quotes with escapes on interior quotes
+** as needed. BLOBs are encoded as hexadecimal literals. Strings with
+** embedded NUL characters cannot be represented as string literals in SQL
+** and hence the returned string literal is truncated prior to the first NUL.
+*/
+static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
+  sqlite3_str str;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  sqlite3StrAccumInit(&str, db, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
+  sqlite3QuoteValue(&str,argv[0]);
+  sqlite3_result_text(context, sqlite3StrAccumFinish(&str), str.nChar,
+                      SQLITE_DYNAMIC);
+  if( str.accError!=SQLITE_OK ){
+    sqlite3_result_null(context);
+    sqlite3_result_error_code(context, str.accError);
+  }
+}
+
+/*
+** The unicode() function.  Return the integer unicode code-point value
+** for the first character of the input string.
+*/
+static void unicodeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *z = sqlite3_value_text(argv[0]);
+  (void)argc;
+  if( z && z[0] ) sqlite3_result_int(context, sqlite3Utf8Read(&z));
+}
+
+/*
+** The char() function takes zero or more arguments, each of which is
+** an integer.  It constructs a string where each character of the string
+** is the unicode character for the corresponding integer argument.
+*/
+static void charFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  unsigned char *z, *zOut;
+  int i;
+  zOut = z = sqlite3_malloc64( argc*4+1 );
+  if( z==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+  for(i=0; i<argc; i++){
+    sqlite3_int64 x;
+    unsigned c;
+    x = sqlite3_value_int64(argv[i]);
+    if( x<0 || x>0x10ffff ) x = 0xfffd;
+    c = (unsigned)(x & 0x1fffff);
+    if( c<0x00080 ){
+      *zOut++ = (u8)(c&0xFF);
+    }else if( c<0x00800 ){
+      *zOut++ = 0xC0 + (u8)((c>>6)&0x1F);
+      *zOut++ = 0x80 + (u8)(c & 0x3F);
+    }else if( c<0x10000 ){
+      *zOut++ = 0xE0 + (u8)((c>>12)&0x0F);
+      *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);
+      *zOut++ = 0x80 + (u8)(c & 0x3F);
+    }else{
+      *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);
+      *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);
+      *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);
+      *zOut++ = 0x80 + (u8)(c & 0x3F);
+    }                                                    \
+  }
+  *zOut = 0;
+  sqlite3_result_text64(context, (char*)z, zOut-z, sqlite3_free, SQLITE_UTF8);
+}
+
+/*
+** The hex() function.  Interpret the argument as a blob.  Return
+** a hexadecimal rendering as text.
+*/
+static void hexFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int i, n;
+  const unsigned char *pBlob;
+  char *zHex, *z;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  pBlob = sqlite3_value_blob(argv[0]);
+  n = sqlite3_value_bytes(argv[0]);
+  assert( pBlob==sqlite3_value_blob(argv[0]) );  /* No encoding change */
+  z = zHex = contextMalloc(context, ((i64)n)*2 + 1);
+  if( zHex ){
+    for(i=0; i<n; i++, pBlob++){
+      unsigned char c = *pBlob;
+      *(z++) = hexdigits[(c>>4)&0xf];
+      *(z++) = hexdigits[c&0xf];
+    }
+    *z = 0;
+    sqlite3_result_text64(context, zHex, (u64)(z-zHex),
+                          sqlite3_free, SQLITE_UTF8);
+  }
+}
+
+/*
+** Buffer zStr contains nStr bytes of utf-8 encoded text. Return 1 if zStr
+** contains character ch, or 0 if it does not.
+*/
+static int strContainsChar(const u8 *zStr, int nStr, u32 ch){
+  const u8 *zEnd = &zStr[nStr];
+  const u8 *z = zStr;
+  while( z<zEnd ){
+    u32 tst = Utf8Read(z);
+    if( tst==ch ) return 1;
+  }
+  return 0;
+}
+
+/*
+** The unhex() function. This function may be invoked with either one or
+** two arguments. In both cases the first argument is interpreted as text
+** a text value containing a set of pairs of hexadecimal digits which are
+** decoded and returned as a blob.
+**
+** If there is only a single argument, then it must consist only of an
+** even number of hexadecimal digits. Otherwise, return NULL.
+**
+** Or, if there is a second argument, then any character that appears in
+** the second argument is also allowed to appear between pairs of hexadecimal
+** digits in the first argument. If any other character appears in the
+** first argument, or if one of the allowed characters appears between
+** two hexadecimal digits that make up a single byte, NULL is returned.
+**
+** The following expressions are all true:
+**
+**     unhex('ABCD')       IS x'ABCD'
+**     unhex('AB CD')      IS NULL
+**     unhex('AB CD', ' ') IS x'ABCD'
+**     unhex('A BCD', ' ') IS NULL
+*/
+static void unhexFunc(
+  sqlite3_context *pCtx,
+  int argc,
+  sqlite3_value **argv
+){
+  const u8 *zPass = (const u8*)"";
+  int nPass = 0;
+  const u8 *zHex = sqlite3_value_text(argv[0]);
+  int nHex = sqlite3_value_bytes(argv[0]);
+#ifdef SQLITE_DEBUG
+  const u8 *zEnd = zHex ? &zHex[nHex] : 0;
+#endif
+  u8 *pBlob = 0;
+  u8 *p = 0;
+
+  assert( argc==1 || argc==2 );
+  if( argc==2 ){
+    zPass = sqlite3_value_text(argv[1]);
+    nPass = sqlite3_value_bytes(argv[1]);
+  }
+  if( !zHex || !zPass ) return;
+
+  p = pBlob = contextMalloc(pCtx, (nHex/2)+1);
+  if( pBlob ){
+    u8 c;                         /* Most significant digit of next byte */
+    u8 d;                         /* Least significant digit of next byte */
+
+    while( (c = *zHex)!=0x00 ){
+      while( !sqlite3Isxdigit(c) ){
+        u32 ch = Utf8Read(zHex);
+        assert( zHex<=zEnd );
+        if( !strContainsChar(zPass, nPass, ch) ) goto unhex_null;
+        c = *zHex;
+        if( c==0x00 ) goto unhex_done;
+      }
+      zHex++;
+      assert( *zEnd==0x00 );
+      assert( zHex<=zEnd );
+      d = *(zHex++);
+      if( !sqlite3Isxdigit(d) ) goto unhex_null;
+      *(p++) = (sqlite3HexToInt(c)<<4) | sqlite3HexToInt(d);
+    }
+  }
+
+ unhex_done:
+  sqlite3_result_blob(pCtx, pBlob, (p - pBlob), sqlite3_free);
+  return;
+
+ unhex_null:
+  sqlite3_free(pBlob);
+  return;
+}
+
+
+/*
+** The zeroblob(N) function returns a zero-filled blob of size N bytes.
+*/
+static void zeroblobFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  i64 n;
+  int rc;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  n = sqlite3_value_int64(argv[0]);
+  if( n<0 ) n = 0;
+  rc = sqlite3_result_zeroblob64(context, n); /* IMP: R-00293-64994 */
+  if( rc ){
+    sqlite3_result_error_code(context, rc);
+  }
+}
+
+/*
+** The replace() function.  Three arguments are all strings: call
+** them A, B, and C. The result is also a string which is derived
+** from A by replacing every occurrence of B with C.  The match
+** must be exact.  Collating sequences are not used.
+*/
+static void replaceFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zStr;        /* The input string A */
+  const unsigned char *zPattern;    /* The pattern string B */
+  const unsigned char *zRep;        /* The replacement string C */
+  unsigned char *zOut;              /* The output */
+  int nStr;                /* Size of zStr */
+  int nPattern;            /* Size of zPattern */
+  int nRep;                /* Size of zRep */
+  i64 nOut;                /* Maximum size of zOut */
+  int loopLimit;           /* Last zStr[] that might match zPattern[] */
+  int i, j;                /* Loop counters */
+  unsigned cntExpand;      /* Number zOut expansions */
+  sqlite3 *db = sqlite3_context_db_handle(context);
+
+  assert( argc==3 );
+  UNUSED_PARAMETER(argc);
+  zStr = sqlite3_value_text(argv[0]);
+  if( zStr==0 ) return;
+  nStr = sqlite3_value_bytes(argv[0]);
+  assert( zStr==sqlite3_value_text(argv[0]) );  /* No encoding change */
+  zPattern = sqlite3_value_text(argv[1]);
+  if( zPattern==0 ){
+    assert( sqlite3_value_type(argv[1])==SQLITE_NULL
+            || sqlite3_context_db_handle(context)->mallocFailed );
+    return;
+  }
+  if( zPattern[0]==0 ){
+    assert( sqlite3_value_type(argv[1])!=SQLITE_NULL );
+    sqlite3_result_text(context, (const char*)zStr, nStr, SQLITE_TRANSIENT);
+    return;
+  }
+  nPattern = sqlite3_value_bytes(argv[1]);
+  assert( zPattern==sqlite3_value_text(argv[1]) );  /* No encoding change */
+  zRep = sqlite3_value_text(argv[2]);
+  if( zRep==0 ) return;
+  nRep = sqlite3_value_bytes(argv[2]);
+  assert( zRep==sqlite3_value_text(argv[2]) );
+  nOut = nStr + 1;
+  assert( nOut<SQLITE_MAX_LENGTH );
+  zOut = contextMalloc(context, (i64)nOut);
+  if( zOut==0 ){
+    return;
+  }
+  loopLimit = nStr - nPattern;
+  cntExpand = 0;
+  for(i=j=0; i<=loopLimit; i++){
+    if( zStr[i]!=zPattern[0] || memcmp(&zStr[i], zPattern, nPattern) ){
+      zOut[j++] = zStr[i];
+    }else{
+      if( nRep>nPattern ){
+        nOut += nRep - nPattern;
+        testcase( nOut-1==db->aLimit[SQLITE_LIMIT_LENGTH] );
+        testcase( nOut-2==db->aLimit[SQLITE_LIMIT_LENGTH] );
+        if( nOut-1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+          sqlite3_result_error_toobig(context);
+          sqlite3_free(zOut);
+          return;
+        }
+        cntExpand++;
+        if( (cntExpand&(cntExpand-1))==0 ){
+          /* Grow the size of the output buffer only on substitutions
+          ** whose index is a power of two: 1, 2, 4, 8, 16, 32, ... */
+          u8 *zOld;
+          zOld = zOut;
+          zOut = sqlite3Realloc(zOut, (int)nOut + (nOut - nStr - 1));
+          if( zOut==0 ){
+            sqlite3_result_error_nomem(context);
+            sqlite3_free(zOld);
+            return;
+          }
+        }
+      }
+      memcpy(&zOut[j], zRep, nRep);
+      j += nRep;
+      i += nPattern-1;
+    }
+  }
+  assert( j+nStr-i+1<=nOut );
+  memcpy(&zOut[j], &zStr[i], nStr-i);
+  j += nStr - i;
+  assert( j<=nOut );
+  zOut[j] = 0;
+  sqlite3_result_text(context, (char*)zOut, j, sqlite3_free);
+}
+
+/*
+** Implementation of the TRIM(), LTRIM(), and RTRIM() functions.
+** The userdata is 0x1 for left trim, 0x2 for right trim, 0x3 for both.
+*/
+static void trimFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zIn;         /* Input string */
+  const unsigned char *zCharSet;    /* Set of characters to trim */
+  unsigned int nIn;                 /* Number of bytes in input */
+  int flags;                        /* 1: trimleft  2: trimright  3: trim */
+  int i;                            /* Loop counter */
+  unsigned int *aLen = 0;           /* Length of each character in zCharSet */
+  unsigned char **azChar = 0;       /* Individual characters in zCharSet */
+  int nChar;                        /* Number of characters in zCharSet */
+
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
+    return;
+  }
+  zIn = sqlite3_value_text(argv[0]);
+  if( zIn==0 ) return;
+  nIn = (unsigned)sqlite3_value_bytes(argv[0]);
+  assert( zIn==sqlite3_value_text(argv[0]) );
+  if( argc==1 ){
+    static const unsigned lenOne[] = { 1 };
+    static unsigned char * const azOne[] = { (u8*)" " };
+    nChar = 1;
+    aLen = (unsigned*)lenOne;
+    azChar = (unsigned char **)azOne;
+    zCharSet = 0;
+  }else if( (zCharSet = sqlite3_value_text(argv[1]))==0 ){
+    return;
+  }else{
+    const unsigned char *z;
+    for(z=zCharSet, nChar=0; *z; nChar++){
+      SQLITE_SKIP_UTF8(z);
+    }
+    if( nChar>0 ){
+      azChar = contextMalloc(context,
+                     ((i64)nChar)*(sizeof(char*)+sizeof(unsigned)));
+      if( azChar==0 ){
+        return;
+      }
+      aLen = (unsigned*)&azChar[nChar];
+      for(z=zCharSet, nChar=0; *z; nChar++){
+        azChar[nChar] = (unsigned char *)z;
+        SQLITE_SKIP_UTF8(z);
+        aLen[nChar] = (unsigned)(z - azChar[nChar]);
+      }
+    }
+  }
+  if( nChar>0 ){
+    flags = SQLITE_PTR_TO_INT(sqlite3_user_data(context));
+    if( flags & 1 ){
+      while( nIn>0 ){
+        unsigned int len = 0;
+        for(i=0; i<nChar; i++){
+          len = aLen[i];
+          if( len<=nIn && memcmp(zIn, azChar[i], len)==0 ) break;
+        }
+        if( i>=nChar ) break;
+        zIn += len;
+        nIn -= len;
+      }
+    }
+    if( flags & 2 ){
+      while( nIn>0 ){
+        unsigned int len = 0;
+        for(i=0; i<nChar; i++){
+          len = aLen[i];
+          if( len<=nIn && memcmp(&zIn[nIn-len],azChar[i],len)==0 ) break;
+        }
+        if( i>=nChar ) break;
+        nIn -= len;
+      }
+    }
+    if( zCharSet ){
+      sqlite3_free(azChar);
+    }
+  }
+  sqlite3_result_text(context, (char*)zIn, nIn, SQLITE_TRANSIENT);
+}
+
+/* The core implementation of the CONCAT(...) and CONCAT_WS(SEP,...)
+** functions.
+**
+** Return a string value that is the concatenation of all non-null
+** entries in argv[].  Use zSep as the separator.
+*/
+static void concatFuncCore(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv,
+  int nSep,
+  const char *zSep
+){
+  i64 j, k, n = 0;
+  int i;
+  char *z;
+  for(i=0; i<argc; i++){
+    n += sqlite3_value_bytes(argv[i]);
+  }
+  n += (argc-1)*(i64)nSep;
+  z = sqlite3_malloc64(n+1);
+  if( z==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+  j = 0;
+  for(i=0; i<argc; i++){
+    k = sqlite3_value_bytes(argv[i]);
+    if( k>0 ){
+      const char *v = (const char*)sqlite3_value_text(argv[i]);
+      if( v!=0 ){
+        if( j>0 && nSep>0 ){
+          memcpy(&z[j], zSep, nSep);
+          j += nSep;
+        }
+        memcpy(&z[j], v, k);
+        j += k;
+      }
+    }
+  }
+  z[j] = 0;
+  assert( j<=n );
+  sqlite3_result_text64(context, z, j, sqlite3_free, SQLITE_UTF8);
+}
+
+/*
+** The CONCAT(...) function.  Generate a string result that is the
+** concatentation of all non-null arguments.
+*/
+static void concatFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  concatFuncCore(context, argc, argv, 0, "");
+}
+
+/*
+** The CONCAT_WS(separator, ...) function.
+**
+** Generate a string that is the concatenation of 2nd through the Nth
+** argument.  Use the first argument (which must be non-NULL) as the
+** separator.
+*/
+static void concatwsFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int nSep = sqlite3_value_bytes(argv[0]);
+  const char *zSep = (const char*)sqlite3_value_text(argv[0]);
+  if( zSep==0 ) return;
+  concatFuncCore(context, argc-1, argv+1, nSep, zSep);
+}
+
+
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+/*
+** The "unknown" function is automatically substituted in place of
+** any unrecognized function name when doing an EXPLAIN or EXPLAIN QUERY PLAN
+** when the SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION compile-time option is used.
+** When the "sqlite3" command-line shell is built using this functionality,
+** that allows an EXPLAIN or EXPLAIN QUERY PLAN for complex queries
+** involving application-defined functions to be examined in a generic
+** sqlite3 shell.
+*/
+static void unknownFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  /* no-op */
+  (void)context;
+  (void)argc;
+  (void)argv;
+}
+#endif /*SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION*/
+
+
+/* IMP: R-25361-16150 This function is omitted from SQLite by default. It
+** is only available if the SQLITE_SOUNDEX compile-time option is used
+** when SQLite is built.
+*/
+#ifdef SQLITE_SOUNDEX
+/*
+** Compute the soundex encoding of a word.
+**
+** IMP: R-59782-00072 The soundex(X) function returns a string that is the
+** soundex encoding of the string X.
+*/
+static void soundexFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  char zResult[8];
+  const u8 *zIn;
+  int i, j;
+  static const unsigned char iCode[] = {
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
+    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
+    0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
+    1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
+  };
+  assert( argc==1 );
+  zIn = (u8*)sqlite3_value_text(argv[0]);
+  if( zIn==0 ) zIn = (u8*)"";
+  for(i=0; zIn[i] && !sqlite3Isalpha(zIn[i]); i++){}
+  if( zIn[i] ){
+    u8 prevcode = iCode[zIn[i]&0x7f];
+    zResult[0] = sqlite3Toupper(zIn[i]);
+    for(j=1; j<4 && zIn[i]; i++){
+      int code = iCode[zIn[i]&0x7f];
+      if( code>0 ){
+        if( code!=prevcode ){
+          prevcode = code;
+          zResult[j++] = code + '0';
+        }
+      }else{
+        prevcode = 0;
+      }
+    }
+    while( j<4 ){
+      zResult[j++] = '0';
+    }
+    zResult[j] = 0;
+    sqlite3_result_text(context, zResult, 4, SQLITE_TRANSIENT);
+  }else{
+    /* IMP: R-64894-50321 The string "?000" is returned if the argument
+    ** is NULL or contains no ASCII alphabetic characters. */
+    sqlite3_result_text(context, "?000", 4, SQLITE_STATIC);
+  }
+}
+#endif /* SQLITE_SOUNDEX */
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** A function that loads a shared-library extension then returns NULL.
+*/
+static void loadExt(sqlite3_context *context, int argc, sqlite3_value **argv){
+  const char *zFile = (const char *)sqlite3_value_text(argv[0]);
+  const char *zProc;
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  char *zErrMsg = 0;
+
+  /* Disallow the load_extension() SQL function unless the SQLITE_LoadExtFunc
+  ** flag is set.  See the sqlite3_enable_load_extension() API.
+  */
+  if( (db->flags & SQLITE_LoadExtFunc)==0 ){
+    sqlite3_result_error(context, "not authorized", -1);
+    return;
+  }
+
+  if( argc==2 ){
+    zProc = (const char *)sqlite3_value_text(argv[1]);
+  }else{
+    zProc = 0;
+  }
+  if( zFile && sqlite3_load_extension(db, zFile, zProc, &zErrMsg) ){
+    sqlite3_result_error(context, zErrMsg, -1);
+    sqlite3_free(zErrMsg);
+  }
+}
+#endif
+
+
+/*
+** An instance of the following structure holds the context of a
+** sum() or avg() aggregate computation.
+*/
+typedef struct SumCtx SumCtx;
+struct SumCtx {
+  double rSum;      /* Running sum as as a double */
+  double rErr;      /* Error term for Kahan-Babushka-Neumaier summation */
+  i64 iSum;         /* Running sum as a signed integer */
+  i64 cnt;          /* Number of elements summed */
+  u8 approx;        /* True if any non-integer value was input to the sum */
+  u8 ovrfl;         /* Integer overflow seen */
+};
+
+/*
+** Do one step of the Kahan-Babushka-Neumaier summation.
+**
+** https://en.wikipedia.org/wiki/Kahan_summation_algorithm
+**
+** Variables are marked "volatile" to defeat c89 x86 floating point
+** optimizations can mess up this algorithm.
+*/
+static void kahanBabuskaNeumaierStep(
+  volatile SumCtx *pSum,
+  volatile double r
+){
+  volatile double s = pSum->rSum;
+  volatile double t = s + r;
+  if( fabs(s) > fabs(r) ){
+    pSum->rErr += (s - t) + r;
+  }else{
+    pSum->rErr += (r - t) + s;
+  }
+  pSum->rSum = t;
+}
+
+/*
+** Add a (possibly large) integer to the running sum.
+*/
+static void kahanBabuskaNeumaierStepInt64(volatile SumCtx *pSum, i64 iVal){
+  if( iVal<=-4503599627370496LL || iVal>=+4503599627370496LL ){
+    i64 iBig, iSm;
+    iSm = iVal % 16384;
+    iBig = iVal - iSm;
+    kahanBabuskaNeumaierStep(pSum, iBig);
+    kahanBabuskaNeumaierStep(pSum, iSm);
+  }else{
+    kahanBabuskaNeumaierStep(pSum, (double)iVal);
+  }
+}
+
+/*
+** Initialize the Kahan-Babaska-Neumaier sum from a 64-bit integer
+*/
+static void kahanBabuskaNeumaierInit(
+  volatile SumCtx *p,
+  i64 iVal
+){
+  if( iVal<=-4503599627370496LL || iVal>=+4503599627370496LL ){
+    i64 iSm = iVal % 16384;
+    p->rSum = (double)(iVal - iSm);
+    p->rErr = (double)iSm;
+  }else{
+    p->rSum = (double)iVal;
+    p->rErr = 0.0;
+  }
+}
+
+/*
+** Routines used to compute the sum, average, and total.
+**
+** The SUM() function follows the (broken) SQL standard which means
+** that it returns NULL if it sums over no inputs.  TOTAL returns
+** 0.0 in that case.  In addition, TOTAL always returns a float where
+** SUM might return an integer if it never encounters a floating point
+** value.  TOTAL never fails, but SUM might through an exception if
+** it overflows an integer.
+*/
+static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
+  SumCtx *p;
+  int type;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  p = sqlite3_aggregate_context(context, sizeof(*p));
+  type = sqlite3_value_numeric_type(argv[0]);
+  if( p && type!=SQLITE_NULL ){
+    p->cnt++;
+    if( p->approx==0 ){
+      if( type!=SQLITE_INTEGER ){
+        kahanBabuskaNeumaierInit(p, p->iSum);
+        p->approx = 1;
+        kahanBabuskaNeumaierStep(p, sqlite3_value_double(argv[0]));
+      }else{
+        i64 x = p->iSum;
+        if( sqlite3AddInt64(&x, sqlite3_value_int64(argv[0]))==0 ){
+          p->iSum = x;
+        }else{
+          p->ovrfl = 1;
+          kahanBabuskaNeumaierInit(p, p->iSum);
+          p->approx = 1;
+          kahanBabuskaNeumaierStepInt64(p, sqlite3_value_int64(argv[0]));
+        }
+      }
+    }else{
+      if( type==SQLITE_INTEGER ){
+        kahanBabuskaNeumaierStepInt64(p, sqlite3_value_int64(argv[0]));
+      }else{
+        p->ovrfl = 0;
+        kahanBabuskaNeumaierStep(p, sqlite3_value_double(argv[0]));
+      }
+    }
+  }
+}
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void sumInverse(sqlite3_context *context, int argc, sqlite3_value**argv){
+  SumCtx *p;
+  int type;
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  p = sqlite3_aggregate_context(context, sizeof(*p));
+  type = sqlite3_value_numeric_type(argv[0]);
+  /* p is always non-NULL because sumStep() will have been called first
+  ** to initialize it */
+  if( ALWAYS(p) && type!=SQLITE_NULL ){
+    assert( p->cnt>0 );
+    p->cnt--;
+    if( !p->approx ){
+      if( sqlite3SubInt64(&p->iSum, sqlite3_value_int64(argv[0])) ){
+        p->ovrfl = 1;
+        p->approx = 1;
+      }
+    }else if( type==SQLITE_INTEGER ){
+      i64 iVal = sqlite3_value_int64(argv[0]);
+      if( iVal!=SMALLEST_INT64 ){
+        kahanBabuskaNeumaierStepInt64(p, -iVal);
+      }else{
+        kahanBabuskaNeumaierStepInt64(p, LARGEST_INT64);
+        kahanBabuskaNeumaierStepInt64(p, 1);
+      }
+    }else{
+      kahanBabuskaNeumaierStep(p, -sqlite3_value_double(argv[0]));
+    }
+  }
+}
+#else
+# define sumInverse 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+static void sumFinalize(sqlite3_context *context){
+  SumCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  if( p && p->cnt>0 ){
+    if( p->approx ){
+      if( p->ovrfl ){
+        sqlite3_result_error(context,"integer overflow",-1);
+      }else if( !sqlite3IsOverflow(p->rErr) ){
+        sqlite3_result_double(context, p->rSum+p->rErr);
+      }else{
+        sqlite3_result_double(context, p->rSum);
+      }
+    }else{
+      sqlite3_result_int64(context, p->iSum);
+    }
+  }
+}
+static void avgFinalize(sqlite3_context *context){
+  SumCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  if( p && p->cnt>0 ){
+    double r;
+    if( p->approx ){
+      r = p->rSum;
+      if( !sqlite3IsOverflow(p->rErr) ) r += p->rErr;
+    }else{
+      r = (double)(p->iSum);
+    }
+    sqlite3_result_double(context, r/(double)p->cnt);
+  }
+}
+static void totalFinalize(sqlite3_context *context){
+  SumCtx *p;
+  double r = 0.0;
+  p = sqlite3_aggregate_context(context, 0);
+  if( p ){
+    if( p->approx ){
+      r = p->rSum;
+      if( !sqlite3IsOverflow(p->rErr) ) r += p->rErr;
+    }else{
+      r = (double)(p->iSum);
+    }
+  }
+  sqlite3_result_double(context, r);
+}
+
+/*
+** The following structure keeps track of state information for the
+** count() aggregate function.
+*/
+typedef struct CountCtx CountCtx;
+struct CountCtx {
+  i64 n;
+#ifdef SQLITE_DEBUG
+  int bInverse;                   /* True if xInverse() ever called */
+#endif
+};
+
+/*
+** Routines to implement the count() aggregate function.
+*/
+static void countStep(sqlite3_context *context, int argc, sqlite3_value **argv){
+  CountCtx *p;
+  p = sqlite3_aggregate_context(context, sizeof(*p));
+  if( (argc==0 || SQLITE_NULL!=sqlite3_value_type(argv[0])) && p ){
+    p->n++;
+  }
+
+#ifndef SQLITE_OMIT_DEPRECATED
+  /* The sqlite3_aggregate_count() function is deprecated.  But just to make
+  ** sure it still operates correctly, verify that its count agrees with our
+  ** internal count when using count(*) and when the total count can be
+  ** expressed as a 32-bit integer. */
+  assert( argc==1 || p==0 || p->n>0x7fffffff || p->bInverse
+          || p->n==sqlite3_aggregate_count(context) );
+#endif
+}
+static void countFinalize(sqlite3_context *context){
+  CountCtx *p;
+  p = sqlite3_aggregate_context(context, 0);
+  sqlite3_result_int64(context, p ? p->n : 0);
+}
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void countInverse(sqlite3_context *ctx, int argc, sqlite3_value **argv){
+  CountCtx *p;
+  p = sqlite3_aggregate_context(ctx, sizeof(*p));
+  /* p is always non-NULL since countStep() will have been called first */
+  if( (argc==0 || SQLITE_NULL!=sqlite3_value_type(argv[0])) && ALWAYS(p) ){
+    p->n--;
+#ifdef SQLITE_DEBUG
+    p->bInverse = 1;
+#endif
+  }
+}
+#else
+# define countInverse 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** Routines to implement min() and max() aggregate functions.
+*/
+static void minmaxStep(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  Mem *pArg  = (Mem *)argv[0];
+  Mem *pBest;
+  UNUSED_PARAMETER(NotUsed);
+
+  pBest = (Mem *)sqlite3_aggregate_context(context, sizeof(*pBest));
+  if( !pBest ) return;
+
+  if( sqlite3_value_type(pArg)==SQLITE_NULL ){
+    if( pBest->flags ) sqlite3SkipAccumulatorLoad(context);
+  }else if( pBest->flags ){
+    int max;
+    int cmp;
+    CollSeq *pColl = sqlite3GetFuncCollSeq(context);
+    /* This step function is used for both the min() and max() aggregates,
+    ** the only difference between the two being that the sense of the
+    ** comparison is inverted. For the max() aggregate, the
+    ** sqlite3_user_data() function returns (void *)-1. For min() it
+    ** returns (void *)db, where db is the sqlite3* database pointer.
+    ** Therefore the next statement sets variable 'max' to 1 for the max()
+    ** aggregate, or 0 for min().
+    */
+    max = sqlite3_user_data(context)!=0;
+    cmp = sqlite3MemCompare(pBest, pArg, pColl);
+    if( (max && cmp<0) || (!max && cmp>0) ){
+      sqlite3VdbeMemCopy(pBest, pArg);
+    }else{
+      sqlite3SkipAccumulatorLoad(context);
+    }
+  }else{
+    pBest->db = sqlite3_context_db_handle(context);
+    sqlite3VdbeMemCopy(pBest, pArg);
+  }
+}
+static void minMaxValueFinalize(sqlite3_context *context, int bValue){
+  sqlite3_value *pRes;
+  pRes = (sqlite3_value *)sqlite3_aggregate_context(context, 0);
+  if( pRes ){
+    if( pRes->flags ){
+      sqlite3_result_value(context, pRes);
+    }
+    if( bValue==0 ) sqlite3VdbeMemRelease(pRes);
+  }
+}
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void minMaxValue(sqlite3_context *context){
+  minMaxValueFinalize(context, 1);
+}
+#else
+# define minMaxValue 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+static void minMaxFinalize(sqlite3_context *context){
+  minMaxValueFinalize(context, 0);
+}
+
+/*
+** group_concat(EXPR, ?SEPARATOR?)
+** string_agg(EXPR, SEPARATOR)
+**
+** Content is accumulated in GroupConcatCtx.str with the SEPARATOR
+** coming before the EXPR value, except for the first entry which
+** omits the SEPARATOR.
+**
+** It is tragic that the SEPARATOR goes before the EXPR string.  The
+** groupConcatInverse() implementation would have been easier if the
+** SEPARATOR were appended after EXPR.  And the order is undocumented,
+** so we could change it, in theory.  But the old behavior has been
+** around for so long that we dare not, for fear of breaking something.
+*/
+typedef struct {
+  StrAccum str;          /* The accumulated concatenation */
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  int nAccum;            /* Number of strings presently concatenated */
+  int nFirstSepLength;   /* Used to detect separator length change */
+  /* If pnSepLengths!=0, refs an array of inter-string separator lengths,
+  ** stored as actually incorporated into presently accumulated result.
+  ** (Hence, its slots in use number nAccum-1 between method calls.)
+  ** If pnSepLengths==0, nFirstSepLength is the length used throughout.
+  */
+  int *pnSepLengths;
+#endif
+} GroupConcatCtx;
+
+static void groupConcatStep(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *zVal;
+  GroupConcatCtx *pGCC;
+  const char *zSep;
+  int nVal, nSep;
+  assert( argc==1 || argc==2 );
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  pGCC = (GroupConcatCtx*)sqlite3_aggregate_context(context, sizeof(*pGCC));
+  if( pGCC ){
+    sqlite3 *db = sqlite3_context_db_handle(context);
+    int firstTerm = pGCC->str.mxAlloc==0;
+    pGCC->str.mxAlloc = db->aLimit[SQLITE_LIMIT_LENGTH];
+    if( argc==1 ){
+      if( !firstTerm ){
+        sqlite3_str_appendchar(&pGCC->str, 1, ',');
+      }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      else{
+        pGCC->nFirstSepLength = 1;
+      }
+#endif
+    }else if( !firstTerm ){
+      zSep = (char*)sqlite3_value_text(argv[1]);
+      nSep = sqlite3_value_bytes(argv[1]);
+      if( zSep ){
+        sqlite3_str_append(&pGCC->str, zSep, nSep);
+      }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      else{
+        nSep = 0;
+      }
+      if( nSep != pGCC->nFirstSepLength || pGCC->pnSepLengths != 0 ){
+        int *pnsl = pGCC->pnSepLengths;
+        if( pnsl == 0 ){
+          /* First separator length variation seen, start tracking them. */
+          pnsl = (int*)sqlite3_malloc64((pGCC->nAccum+1) * sizeof(int));
+          if( pnsl!=0 ){
+            int i = 0, nA = pGCC->nAccum-1;
+            while( i<nA ) pnsl[i++] = pGCC->nFirstSepLength;
+          }
+        }else{
+          pnsl = (int*)sqlite3_realloc64(pnsl, pGCC->nAccum * sizeof(int));
+        }
+        if( pnsl!=0 ){
+          if( ALWAYS(pGCC->nAccum>0) ){
+            pnsl[pGCC->nAccum-1] = nSep;
+          }
+          pGCC->pnSepLengths = pnsl;
+        }else{
+          sqlite3StrAccumSetError(&pGCC->str, SQLITE_NOMEM);
+        }
+      }
+#endif
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    else{
+      pGCC->nFirstSepLength = sqlite3_value_bytes(argv[1]);
+    }
+    pGCC->nAccum += 1;
+#endif
+    zVal = (char*)sqlite3_value_text(argv[0]);
+    nVal = sqlite3_value_bytes(argv[0]);
+    if( zVal ) sqlite3_str_append(&pGCC->str, zVal, nVal);
+  }
+}
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void groupConcatInverse(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GroupConcatCtx *pGCC;
+  assert( argc==1 || argc==2 );
+  (void)argc;  /* Suppress unused parameter warning */
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
+  pGCC = (GroupConcatCtx*)sqlite3_aggregate_context(context, sizeof(*pGCC));
+  /* pGCC is always non-NULL since groupConcatStep() will have always
+  ** run first to initialize it */
+  if( ALWAYS(pGCC) ){
+    int nVS;  /* Number of characters to remove */
+    /* Must call sqlite3_value_text() to convert the argument into text prior
+    ** to invoking sqlite3_value_bytes(), in case the text encoding is UTF16 */
+    (void)sqlite3_value_text(argv[0]);
+    nVS = sqlite3_value_bytes(argv[0]);
+    pGCC->nAccum -= 1;
+    if( pGCC->pnSepLengths!=0 ){
+      assert(pGCC->nAccum >= 0);
+      if( pGCC->nAccum>0 ){
+        nVS += *pGCC->pnSepLengths;
+        memmove(pGCC->pnSepLengths, pGCC->pnSepLengths+1,
+               (pGCC->nAccum-1)*sizeof(int));
+      }
+    }else{
+      /* If removing single accumulated string, harmlessly over-do. */
+      nVS += pGCC->nFirstSepLength;
+    }
+    if( nVS>=(int)pGCC->str.nChar ){
+      pGCC->str.nChar = 0;
+    }else{
+      pGCC->str.nChar -= nVS;
+      memmove(pGCC->str.zText, &pGCC->str.zText[nVS], pGCC->str.nChar);
+    }
+    if( pGCC->str.nChar==0 ){
+      pGCC->str.mxAlloc = 0;
+      sqlite3_free(pGCC->pnSepLengths);
+      pGCC->pnSepLengths = 0;
+    }
+  }
+}
+#else
+# define groupConcatInverse 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+static void groupConcatFinalize(sqlite3_context *context){
+  GroupConcatCtx *pGCC
+    = (GroupConcatCtx*)sqlite3_aggregate_context(context, 0);
+  if( pGCC ){
+    sqlite3ResultStrAccum(context, &pGCC->str);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    sqlite3_free(pGCC->pnSepLengths);
+#endif
+  }
+}
+#ifndef SQLITE_OMIT_WINDOWFUNC
+static void groupConcatValue(sqlite3_context *context){
+  GroupConcatCtx *pGCC
+    = (GroupConcatCtx*)sqlite3_aggregate_context(context, 0);
+  if( pGCC ){
+    StrAccum *pAccum = &pGCC->str;
+    if( pAccum->accError==SQLITE_TOOBIG ){
+      sqlite3_result_error_toobig(context);
+    }else if( pAccum->accError==SQLITE_NOMEM ){
+      sqlite3_result_error_nomem(context);
+    }else if( pGCC->nAccum>0 && pAccum->nChar==0 ){
+      sqlite3_result_text(context, "", 1, SQLITE_STATIC);
+    }else{
+      const char *zText = sqlite3_str_value(pAccum);
+      sqlite3_result_text(context, zText, pAccum->nChar, SQLITE_TRANSIENT);
+    }
+  }
+}
+#else
+# define groupConcatValue 0
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** This routine does per-connection function registration.  Most
+** of the built-in functions above are part of the global function set.
+** This routine only deals with those that are not global.
+*/
+SQLITE_PRIVATE void sqlite3RegisterPerConnectionBuiltinFunctions(sqlite3 *db){
+  int rc = sqlite3_overload_function(db, "MATCH", 2);
+  assert( rc==SQLITE_NOMEM || rc==SQLITE_OK );
+  if( rc==SQLITE_NOMEM ){
+    sqlite3OomFault(db);
+  }
+}
+
+/*
+** Re-register the built-in LIKE functions.  The caseSensitive
+** parameter determines whether or not the LIKE operator is case
+** sensitive.
+*/
+SQLITE_PRIVATE void sqlite3RegisterLikeFunctions(sqlite3 *db, int caseSensitive){
+  FuncDef *pDef;
+  struct compareInfo *pInfo;
+  int flags;
+  int nArg;
+  if( caseSensitive ){
+    pInfo = (struct compareInfo*)&likeInfoAlt;
+    flags = SQLITE_FUNC_LIKE | SQLITE_FUNC_CASE;
+  }else{
+    pInfo = (struct compareInfo*)&likeInfoNorm;
+    flags = SQLITE_FUNC_LIKE;
+  }
+  for(nArg=2; nArg<=3; nArg++){
+    sqlite3CreateFunc(db, "like", nArg, SQLITE_UTF8, pInfo, likeFunc,
+                      0, 0, 0, 0, 0);
+    pDef = sqlite3FindFunction(db, "like", nArg, SQLITE_UTF8, 0);
+    pDef->funcFlags |= flags;
+    pDef->funcFlags &= ~SQLITE_FUNC_UNSAFE;
+  }
+}
+
+/*
+** pExpr points to an expression which implements a function.  If
+** it is appropriate to apply the LIKE optimization to that function
+** then set aWc[0] through aWc[2] to the wildcard characters and the
+** escape character and then return TRUE.  If the function is not a
+** LIKE-style function then return FALSE.
+**
+** The expression "a LIKE b ESCAPE c" is only considered a valid LIKE
+** operator if c is a string literal that is exactly one byte in length.
+** That one byte is stored in aWc[3].  aWc[3] is set to zero if there is
+** no ESCAPE clause.
+**
+** *pIsNocase is set to true if uppercase and lowercase are equivalent for
+** the function (default for LIKE).  If the function makes the distinction
+** between uppercase and lowercase (as does GLOB) then *pIsNocase is set to
+** false.
+*/
+SQLITE_PRIVATE int sqlite3IsLikeFunction(sqlite3 *db, Expr *pExpr, int *pIsNocase, char *aWc){
+  FuncDef *pDef;
+  int nExpr;
+  assert( pExpr!=0 );
+  assert( pExpr->op==TK_FUNCTION );
+  assert( ExprUseXList(pExpr) );
+  if( !pExpr->x.pList ){
+    return 0;
+  }
+  nExpr = pExpr->x.pList->nExpr;
+  assert( !ExprHasProperty(pExpr, EP_IntValue) );
+  pDef = sqlite3FindFunction(db, pExpr->u.zToken, nExpr, SQLITE_UTF8, 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+  if( pDef==0 ) return 0;
+#endif
+  if( NEVER(pDef==0) || (pDef->funcFlags & SQLITE_FUNC_LIKE)==0 ){
+    return 0;
+  }
+
+  /* The memcpy() statement assumes that the wildcard characters are
+  ** the first three statements in the compareInfo structure.  The
+  ** asserts() that follow verify that assumption
+  */
+  memcpy(aWc, pDef->pUserData, 3);
+  assert( (char*)&likeInfoAlt == (char*)&likeInfoAlt.matchAll );
+  assert( &((char*)&likeInfoAlt)[1] == (char*)&likeInfoAlt.matchOne );
+  assert( &((char*)&likeInfoAlt)[2] == (char*)&likeInfoAlt.matchSet );
+
+  if( nExpr<3 ){
+    aWc[3] = 0;
+  }else{
+    Expr *pEscape = pExpr->x.pList->a[2].pExpr;
+    char *zEscape;
+    if( pEscape->op!=TK_STRING ) return 0;
+    assert( !ExprHasProperty(pEscape, EP_IntValue) );
+    zEscape = pEscape->u.zToken;
+    if( zEscape[0]==0 || zEscape[1]!=0 ) return 0;
+    if( zEscape[0]==aWc[0] ) return 0;
+    if( zEscape[0]==aWc[1] ) return 0;
+    aWc[3] = zEscape[0];
+  }
+
+  *pIsNocase = (pDef->funcFlags & SQLITE_FUNC_CASE)==0;
+  return 1;
+}
+
+/* Mathematical Constants */
+#ifndef M_PI
+# define M_PI   3.141592653589793238462643383279502884
+#endif
+#ifndef M_LN10
+# define M_LN10 2.302585092994045684017991454684364208
+#endif
+#ifndef M_LN2
+# define M_LN2  0.693147180559945309417232121458176568
+#endif
+
+
+/* Extra math functions that require linking with -lm
+*/
+#ifdef SQLITE_ENABLE_MATH_FUNCTIONS
+/*
+** Implementation SQL functions:
+**
+**   ceil(X)
+**   ceiling(X)
+**   floor(X)
+**
+** The sqlite3_user_data() pointer is a pointer to the libm implementation
+** of the underlying C function.
+*/
+static void ceilingFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( argc==1 );
+  switch( sqlite3_value_numeric_type(argv[0]) ){
+    case SQLITE_INTEGER: {
+       sqlite3_result_int64(context, sqlite3_value_int64(argv[0]));
+       break;
+    }
+    case SQLITE_FLOAT: {
+       double (*x)(double) = (double(*)(double))sqlite3_user_data(context);
+       sqlite3_result_double(context, x(sqlite3_value_double(argv[0])));
+       break;
+    }
+    default: {
+       break;
+    }
+  }
+}
+
+/*
+** On some systems, ceil() and floor() are intrinsic function.  You are
+** unable to take a pointer to these functions.  Hence, we here wrap them
+** in our own actual functions.
+*/
+static double xCeil(double x){ return ceil(x); }
+static double xFloor(double x){ return floor(x); }
+
+/*
+** Some systems do not have log2() and log10() in their standard math
+** libraries.
+*/
+#if defined(HAVE_LOG10) && HAVE_LOG10==0
+# define log10(X) (0.4342944819032517867*log(X))
+#endif
+#if defined(HAVE_LOG2) && HAVE_LOG2==0
+# define log2(X) (1.442695040888963456*log(X))
+#endif
+
+
+/*
+** Implementation of SQL functions:
+**
+**   ln(X)       - natural logarithm
+**   log(X)      - log X base 10
+**   log10(X)    - log X base 10
+**   log(B,X)    - log X base B
+*/
+static void logFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  double x, b, ans;
+  assert( argc==1 || argc==2 );
+  switch( sqlite3_value_numeric_type(argv[0]) ){
+    case SQLITE_INTEGER:
+    case SQLITE_FLOAT:
+      x = sqlite3_value_double(argv[0]);
+      if( x<=0.0 ) return;
+      break;
+    default:
+      return;
+  }
+  if( argc==2 ){
+    switch( sqlite3_value_numeric_type(argv[0]) ){
+      case SQLITE_INTEGER:
+      case SQLITE_FLOAT:
+        b = log(x);
+        if( b<=0.0 ) return;
+        x = sqlite3_value_double(argv[1]);
+        if( x<=0.0 ) return;
+        break;
+     default:
+        return;
+    }
+    ans = log(x)/b;
+  }else{
+    switch( SQLITE_PTR_TO_INT(sqlite3_user_data(context)) ){
+      case 1:
+        ans = log10(x);
+        break;
+      case 2:
+        ans = log2(x);
+        break;
+      default:
+        ans = log(x);
+        break;
+    }
+  }
+  sqlite3_result_double(context, ans);
+}
+
+/*
+** Functions to converts degrees to radians and radians to degrees.
+*/
+static double degToRad(double x){ return x*(M_PI/180.0); }
+static double radToDeg(double x){ return x*(180.0/M_PI); }
+
+/*
+** Implementation of 1-argument SQL math functions:
+**
+**   exp(X)  - Compute e to the X-th power
+*/
+static void math1Func(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int type0;
+  double v0, ans;
+  double (*x)(double);
+  assert( argc==1 );
+  type0 = sqlite3_value_numeric_type(argv[0]);
+  if( type0!=SQLITE_INTEGER && type0!=SQLITE_FLOAT ) return;
+  v0 = sqlite3_value_double(argv[0]);
+  x = (double(*)(double))sqlite3_user_data(context);
+  ans = x(v0);
+  sqlite3_result_double(context, ans);
+}
+
+/*
+** Implementation of 2-argument SQL math functions:
+**
+**   power(X,Y)  - Compute X to the Y-th power
+*/
+static void math2Func(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int type0, type1;
+  double v0, v1, ans;
+  double (*x)(double,double);
+  assert( argc==2 );
+  type0 = sqlite3_value_numeric_type(argv[0]);
+  if( type0!=SQLITE_INTEGER && type0!=SQLITE_FLOAT ) return;
+  type1 = sqlite3_value_numeric_type(argv[1]);
+  if( type1!=SQLITE_INTEGER && type1!=SQLITE_FLOAT ) return;
+  v0 = sqlite3_value_double(argv[0]);
+  v1 = sqlite3_value_double(argv[1]);
+  x = (double(*)(double,double))sqlite3_user_data(context);
+  ans = x(v0, v1);
+  sqlite3_result_double(context, ans);
+}
+
+/*
+** Implementation of 0-argument pi() function.
+*/
+static void piFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( argc==0 );
+  (void)argv;
+  sqlite3_result_double(context, M_PI);
+}
+
+#endif /* SQLITE_ENABLE_MATH_FUNCTIONS */
+
+/*
+** Implementation of sign(X) function.
+*/
+static void signFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int type0;
+  double x;
+  UNUSED_PARAMETER(argc);
+  assert( argc==1 );
+  type0 = sqlite3_value_numeric_type(argv[0]);
+  if( type0!=SQLITE_INTEGER && type0!=SQLITE_FLOAT ) return;
+  x = sqlite3_value_double(argv[0]);
+  sqlite3_result_int(context, x<0.0 ? -1 : x>0.0 ? +1 : 0);
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Implementation of fpdecode(x,y,z) function.
+**
+** x is a real number that is to be decoded.  y is the precision.
+** z is the maximum real precision.  Return a string that shows the
+** results of the sqlite3FpDecode() function.
+**
+** Used for testing and debugging only, specifically testing and debugging
+** of the sqlite3FpDecode() function.  This SQL function does not appear
+** in production builds.  This function is not an API and is subject to
+** modification or removal in future versions of SQLite.
+*/
+static void fpdecodeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  FpDecode s;
+  double x;
+  int y, z;
+  char zBuf[100];
+  UNUSED_PARAMETER(argc);
+  assert( argc==3 );
+  x = sqlite3_value_double(argv[0]);
+  y = sqlite3_value_int(argv[1]);
+  z = sqlite3_value_int(argv[2]);
+  if( z<=0 ) z = 1;
+  sqlite3FpDecode(&s, x, y, z);
+  if( s.isSpecial==2 ){
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "NaN");
+  }else{
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "%c%.*s/%d", s.sign, s.n, s.z, s.iDP);
+  }
+  sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+}
+#endif /* SQLITE_DEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+** Implementation of parseuri(uri,flags) function.
+**
+** Required Arguments:
+**    "uri"        The URI to parse.
+**    "flags"      Bitmask of flags, as if to sqlite3_open_v2().
+**
+** Additional arguments beyond the first two make calls to
+** sqlite3_uri_key() for integers and sqlite3_uri_parameter for
+** anything else.
+**
+** The result is a string showing the results of calling sqlite3ParseUri().
+**
+** Used for testing and debugging only, specifically testing and debugging
+** of the sqlite3ParseUri() function.  This SQL function does not appear
+** in production builds.  This function is not an API and is subject to
+** modification or removal in future versions of SQLite.
+*/
+static void parseuriFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_str *pResult;
+  const char *zVfs;
+  const char *zUri;
+  unsigned int flgs;
+  int rc;
+  sqlite3_vfs *pVfs = 0;
+  char *zFile = 0;
+  char *zErr = 0;
+
+  if( argc<2 ) return;
+  pVfs = sqlite3_vfs_find(0);
+  assert( pVfs );
+  zVfs = pVfs->zName;
+  zUri = (const char*)sqlite3_value_text(argv[0]);
+  if( zUri==0 ) return;
+  flgs = (unsigned int)sqlite3_value_int(argv[1]);
+  rc = sqlite3ParseUri(zVfs, zUri, &flgs, &pVfs, &zFile, &zErr);
+  pResult = sqlite3_str_new(0);
+  if( pResult ){
+    int i;
+    sqlite3_str_appendf(pResult, "rc=%d", rc);
+    sqlite3_str_appendf(pResult, ", flags=0x%x", flgs);
+    sqlite3_str_appendf(pResult, ", vfs=%Q", pVfs ? pVfs->zName: 0);
+    sqlite3_str_appendf(pResult, ", err=%Q", zErr);
+    sqlite3_str_appendf(pResult, ", file=%Q", zFile);
+    if( zFile ){
+      const char *z = zFile;
+      z += sqlite3Strlen30(z)+1;
+      while( z[0] ){
+        sqlite3_str_appendf(pResult, ", %Q", z);
+        z += sqlite3Strlen30(z)+1;
+      }
+      for(i=2; i<argc; i++){
+        const char *zArg;
+        if( sqlite3_value_type(argv[i])==SQLITE_INTEGER ){
+          int k = sqlite3_value_int(argv[i]);
+          sqlite3_str_appendf(pResult, ", '%d:%q'",k,sqlite3_uri_key(zFile, k));
+        }else if( (zArg = (const char*)sqlite3_value_text(argv[i]))!=0 ){
+          sqlite3_str_appendf(pResult, ", '%q:%q'",
+                 zArg, sqlite3_uri_parameter(zFile,zArg));
+        }else{
+          sqlite3_str_appendf(pResult, ", NULL");
+        }
+      }
+    }
+    sqlite3_result_text(ctx, sqlite3_str_finish(pResult), -1, sqlite3_free);
+  }
+  sqlite3_free_filename(zFile);
+  sqlite3_free(zErr);
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** All of the FuncDef structures in the aBuiltinFunc[] array above
+** to the global function hash table.  This occurs at start-time (as
+** a consequence of calling sqlite3_initialize()).
+**
+** After this routine runs
+*/
+SQLITE_PRIVATE void sqlite3RegisterBuiltinFunctions(void){
+  /*
+  ** The following array holds FuncDef structures for all of the functions
+  ** defined in this file.
+  **
+  ** The array cannot be constant since changes are made to the
+  ** FuncDef.pHash elements at start-time.  The elements of this array
+  ** are read-only after initialization is complete.
+  **
+  ** For peak efficiency, put the most frequently used function last.
+  */
+  static FuncDef aBuiltinFunc[] = {
+/***** Functions only available with SQLITE_TESTCTRL_INTERNAL_FUNCTIONS *****/
+#if !defined(SQLITE_UNTESTABLE)
+    TEST_FUNC(implies_nonnull_row, 2, INLINEFUNC_implies_nonnull_row, 0),
+    TEST_FUNC(expr_compare,        2, INLINEFUNC_expr_compare,        0),
+    TEST_FUNC(expr_implies_expr,   2, INLINEFUNC_expr_implies_expr,   0),
+    TEST_FUNC(affinity,            1, INLINEFUNC_affinity,            0),
+#endif /* !defined(SQLITE_UNTESTABLE) */
+/***** Regular functions *****/
+#ifdef SQLITE_SOUNDEX
+    FUNCTION(soundex,            1, 0, 0, soundexFunc      ),
+#endif
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+    SFUNCTION(load_extension,    1, 0, 0, loadExt          ),
+    SFUNCTION(load_extension,    2, 0, 0, loadExt          ),
+#endif
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+    DFUNCTION(sqlite_compileoption_used,1, 0, 0, compileoptionusedFunc  ),
+    DFUNCTION(sqlite_compileoption_get, 1, 0, 0, compileoptiongetFunc  ),
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+    INLINE_FUNC(unlikely,        1, INLINEFUNC_unlikely, SQLITE_FUNC_UNLIKELY),
+    INLINE_FUNC(likelihood,      2, INLINEFUNC_unlikely, SQLITE_FUNC_UNLIKELY),
+    INLINE_FUNC(likely,          1, INLINEFUNC_unlikely, SQLITE_FUNC_UNLIKELY),
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+    INLINE_FUNC(sqlite_offset,   1, INLINEFUNC_sqlite_offset, 0 ),
+#endif
+    FUNCTION(ltrim,              1, 1, 0, trimFunc         ),
+    FUNCTION(ltrim,              2, 1, 0, trimFunc         ),
+    FUNCTION(rtrim,              1, 2, 0, trimFunc         ),
+    FUNCTION(rtrim,              2, 2, 0, trimFunc         ),
+    FUNCTION(trim,               1, 3, 0, trimFunc         ),
+    FUNCTION(trim,               2, 3, 0, trimFunc         ),
+    FUNCTION(min,               -3, 0, 1, minmaxFunc       ),
+    WAGGREGATE(min, 1, 0, 1, minmaxStep, minMaxFinalize, minMaxValue, 0,
+                                 SQLITE_FUNC_MINMAX|SQLITE_FUNC_ANYORDER ),
+    FUNCTION(max,               -3, 1, 1, minmaxFunc       ),
+    WAGGREGATE(max, 1, 1, 1, minmaxStep, minMaxFinalize, minMaxValue, 0,
+                                 SQLITE_FUNC_MINMAX|SQLITE_FUNC_ANYORDER ),
+    FUNCTION2(typeof,            1, 0, 0, typeofFunc,  SQLITE_FUNC_TYPEOF),
+    FUNCTION2(subtype,           1, 0, 0, subtypeFunc,
+                                           SQLITE_FUNC_TYPEOF|SQLITE_SUBTYPE),
+    FUNCTION2(length,            1, 0, 0, lengthFunc,  SQLITE_FUNC_LENGTH),
+    FUNCTION2(octet_length,      1, 0, 0, bytelengthFunc,SQLITE_FUNC_BYTELEN),
+    FUNCTION(instr,              2, 0, 0, instrFunc        ),
+    FUNCTION(printf,            -1, 0, 0, printfFunc       ),
+    FUNCTION(format,            -1, 0, 0, printfFunc       ),
+    FUNCTION(unicode,            1, 0, 0, unicodeFunc      ),
+    FUNCTION(char,              -1, 0, 0, charFunc         ),
+    FUNCTION(abs,                1, 0, 0, absFunc          ),
+#ifdef SQLITE_DEBUG
+    FUNCTION(fpdecode,           3, 0, 0, fpdecodeFunc     ),
+    FUNCTION(parseuri,          -1, 0, 0, parseuriFunc     ),
+#endif
+#ifndef SQLITE_OMIT_FLOATING_POINT
+    FUNCTION(round,              1, 0, 0, roundFunc        ),
+    FUNCTION(round,              2, 0, 0, roundFunc        ),
+#endif
+    FUNCTION(upper,              1, 0, 0, upperFunc        ),
+    FUNCTION(lower,              1, 0, 0, lowerFunc        ),
+    FUNCTION(hex,                1, 0, 0, hexFunc          ),
+    FUNCTION(unhex,              1, 0, 0, unhexFunc        ),
+    FUNCTION(unhex,              2, 0, 0, unhexFunc        ),
+    FUNCTION(concat,            -3, 0, 0, concatFunc       ),
+    FUNCTION(concat_ws,         -4, 0, 0, concatwsFunc     ),
+    INLINE_FUNC(ifnull,          2, INLINEFUNC_coalesce, 0 ),
+    VFUNCTION(random,            0, 0, 0, randomFunc       ),
+    VFUNCTION(randomblob,        1, 0, 0, randomBlob       ),
+    FUNCTION(nullif,             2, 0, 1, nullifFunc       ),
+    DFUNCTION(sqlite_version,    0, 0, 0, versionFunc      ),
+    DFUNCTION(sqlite_source_id,  0, 0, 0, sourceidFunc     ),
+    FUNCTION(sqlite_log,         2, 0, 0, errlogFunc       ),
+    FUNCTION(quote,              1, 0, 0, quoteFunc        ),
+    VFUNCTION(last_insert_rowid, 0, 0, 0, last_insert_rowid),
+    VFUNCTION(changes,           0, 0, 0, changes          ),
+    VFUNCTION(total_changes,     0, 0, 0, total_changes    ),
+    FUNCTION(replace,            3, 0, 0, replaceFunc      ),
+    FUNCTION(zeroblob,           1, 0, 0, zeroblobFunc     ),
+    FUNCTION(substr,             2, 0, 0, substrFunc       ),
+    FUNCTION(substr,             3, 0, 0, substrFunc       ),
+    FUNCTION(substring,          2, 0, 0, substrFunc       ),
+    FUNCTION(substring,          3, 0, 0, substrFunc       ),
+    WAGGREGATE(sum,   1,0,0, sumStep, sumFinalize, sumFinalize, sumInverse, 0),
+    WAGGREGATE(total, 1,0,0, sumStep,totalFinalize,totalFinalize,sumInverse, 0),
+    WAGGREGATE(avg,   1,0,0, sumStep, avgFinalize, avgFinalize, sumInverse, 0),
+    WAGGREGATE(count, 0,0,0, countStep,
+        countFinalize, countFinalize, countInverse,
+        SQLITE_FUNC_COUNT|SQLITE_FUNC_ANYORDER  ),
+    WAGGREGATE(count, 1,0,0, countStep,
+        countFinalize, countFinalize, countInverse, SQLITE_FUNC_ANYORDER ),
+    WAGGREGATE(group_concat, 1, 0, 0, groupConcatStep,
+        groupConcatFinalize, groupConcatValue, groupConcatInverse, 0),
+    WAGGREGATE(group_concat, 2, 0, 0, groupConcatStep,
+        groupConcatFinalize, groupConcatValue, groupConcatInverse, 0),
+    WAGGREGATE(string_agg,   2, 0, 0, groupConcatStep,
+        groupConcatFinalize, groupConcatValue, groupConcatInverse, 0),
+
+    LIKEFUNC(glob, 2, &globInfo, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),
+#ifdef SQLITE_CASE_SENSITIVE_LIKE
+    LIKEFUNC(like, 2, &likeInfoAlt, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),
+    LIKEFUNC(like, 3, &likeInfoAlt, SQLITE_FUNC_LIKE|SQLITE_FUNC_CASE),
+#else
+    LIKEFUNC(like, 2, &likeInfoNorm, SQLITE_FUNC_LIKE),
+    LIKEFUNC(like, 3, &likeInfoNorm, SQLITE_FUNC_LIKE),
+#endif
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+    FUNCTION(unknown,           -1, 0, 0, unknownFunc      ),
+#endif
+#ifdef SQLITE_ENABLE_MATH_FUNCTIONS
+    MFUNCTION(ceil,              1, xCeil,     ceilingFunc ),
+    MFUNCTION(ceiling,           1, xCeil,     ceilingFunc ),
+    MFUNCTION(floor,             1, xFloor,    ceilingFunc ),
+#if SQLITE_HAVE_C99_MATH_FUNCS
+    MFUNCTION(trunc,             1, trunc,     ceilingFunc ),
+#endif
+    FUNCTION(ln,                 1, 0, 0,      logFunc     ),
+    FUNCTION(log,                1, 1, 0,      logFunc     ),
+    FUNCTION(log10,              1, 1, 0,      logFunc     ),
+    FUNCTION(log2,               1, 2, 0,      logFunc     ),
+    FUNCTION(log,                2, 0, 0,      logFunc     ),
+    MFUNCTION(exp,               1, exp,       math1Func   ),
+    MFUNCTION(pow,               2, pow,       math2Func   ),
+    MFUNCTION(power,             2, pow,       math2Func   ),
+    MFUNCTION(mod,               2, fmod,      math2Func   ),
+    MFUNCTION(acos,              1, acos,      math1Func   ),
+    MFUNCTION(asin,              1, asin,      math1Func   ),
+    MFUNCTION(atan,              1, atan,      math1Func   ),
+    MFUNCTION(atan2,             2, atan2,     math2Func   ),
+    MFUNCTION(cos,               1, cos,       math1Func   ),
+    MFUNCTION(sin,               1, sin,       math1Func   ),
+    MFUNCTION(tan,               1, tan,       math1Func   ),
+    MFUNCTION(cosh,              1, cosh,      math1Func   ),
+    MFUNCTION(sinh,              1, sinh,      math1Func   ),
+    MFUNCTION(tanh,              1, tanh,      math1Func   ),
+#if SQLITE_HAVE_C99_MATH_FUNCS
+    MFUNCTION(acosh,             1, acosh,     math1Func   ),
+    MFUNCTION(asinh,             1, asinh,     math1Func   ),
+    MFUNCTION(atanh,             1, atanh,     math1Func   ),
+#endif
+    MFUNCTION(sqrt,              1, sqrt,      math1Func   ),
+    MFUNCTION(radians,           1, degToRad,  math1Func   ),
+    MFUNCTION(degrees,           1, radToDeg,  math1Func   ),
+    MFUNCTION(pi,                0, 0,         piFunc      ),
+#endif /* SQLITE_ENABLE_MATH_FUNCTIONS */
+    FUNCTION(sign,               1, 0, 0,      signFunc    ),
+    INLINE_FUNC(coalesce,       -4, INLINEFUNC_coalesce, 0 ),
+    INLINE_FUNC(iif,            -4, INLINEFUNC_iif,      0 ),
+    INLINE_FUNC(if,             -4, INLINEFUNC_iif,      0 ),
+  };
+#ifndef SQLITE_OMIT_ALTERTABLE
+  sqlite3AlterFunctions();
+#endif
+  sqlite3WindowFunctions();
+  sqlite3RegisterDateTimeFunctions();
+  sqlite3RegisterJsonFunctions();
+  sqlite3InsertBuiltinFuncs(aBuiltinFunc, ArraySize(aBuiltinFunc));
+
+#if 0  /* Enable to print out how the built-in functions are hashed */
+  {
+    int i;
+    FuncDef *p;
+    for(i=0; i<SQLITE_FUNC_HASH_SZ; i++){
+      printf("FUNC-HASH %02d:", i);
+      for(p=sqlite3BuiltinFunctions.a[i]; p; p=p->u.pHash){
+        int n = sqlite3Strlen30(p->zName);
+        int h = p->zName[0] + n;
+        assert( p->funcFlags & SQLITE_FUNC_BUILTIN );
+        printf(" %s(%d)", p->zName, h);
+      }
+      printf("\n");
+    }
+  }
+#endif
+}
+
+/************** End of func.c ************************************************/
+/************** Begin file fkey.c ********************************************/
+/*
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used by the compiler to add foreign key
+** support to compiled SQL statements.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+#ifndef SQLITE_OMIT_TRIGGER
+
+/*
+** Deferred and Immediate FKs
+** --------------------------
+**
+** Foreign keys in SQLite come in two flavours: deferred and immediate.
+** If an immediate foreign key constraint is violated,
+** SQLITE_CONSTRAINT_FOREIGNKEY is returned and the current
+** statement transaction rolled back. If a
+** deferred foreign key constraint is violated, no action is taken
+** immediately. However if the application attempts to commit the
+** transaction before fixing the constraint violation, the attempt fails.
+**
+** Deferred constraints are implemented using a simple counter associated
+** with the database handle. The counter is set to zero each time a
+** database transaction is opened. Each time a statement is executed
+** that causes a foreign key violation, the counter is incremented. Each
+** time a statement is executed that removes an existing violation from
+** the database, the counter is decremented. When the transaction is
+** committed, the commit fails if the current value of the counter is
+** greater than zero. This scheme has two big drawbacks:
+**
+**   * When a commit fails due to a deferred foreign key constraint,
+**     there is no way to tell which foreign constraint is not satisfied,
+**     or which row it is not satisfied for.
+**
+**   * If the database contains foreign key violations when the
+**     transaction is opened, this may cause the mechanism to malfunction.
+**
+** Despite these problems, this approach is adopted as it seems simpler
+** than the alternatives.
+**
+** INSERT operations:
+**
+**   I.1) For each FK for which the table is the child table, search
+**        the parent table for a match. If none is found increment the
+**        constraint counter.
+**
+**   I.2) For each FK for which the table is the parent table,
+**        search the child table for rows that correspond to the new
+**        row in the parent table. Decrement the counter for each row
+**        found (as the constraint is now satisfied).
+**
+** DELETE operations:
+**
+**   D.1) For each FK for which the table is the child table,
+**        search the parent table for a row that corresponds to the
+**        deleted row in the child table. If such a row is not found,
+**        decrement the counter.
+**
+**   D.2) For each FK for which the table is the parent table, search
+**        the child table for rows that correspond to the deleted row
+**        in the parent table. For each found increment the counter.
+**
+** UPDATE operations:
+**
+**   An UPDATE command requires that all 4 steps above are taken, but only
+**   for FK constraints for which the affected columns are actually
+**   modified (values must be compared at runtime).
+**
+** Note that I.1 and D.1 are very similar operations, as are I.2 and D.2.
+** This simplifies the implementation a bit.
+**
+** For the purposes of immediate FK constraints, the OR REPLACE conflict
+** resolution is considered to delete rows before the new row is inserted.
+** If a delete caused by OR REPLACE violates an FK constraint, an exception
+** is thrown, even if the FK constraint would be satisfied after the new
+** row is inserted.
+**
+** Immediate constraints are usually handled similarly. The only difference
+** is that the counter used is stored as part of each individual statement
+** object (struct Vdbe). If, after the statement has run, its immediate
+** constraint counter is greater than zero,
+** it returns SQLITE_CONSTRAINT_FOREIGNKEY
+** and the statement transaction is rolled back. An exception is an INSERT
+** statement that inserts a single row only (no triggers). In this case,
+** instead of using a counter, an exception is thrown immediately if the
+** INSERT violates a foreign key constraint. This is necessary as such
+** an INSERT does not open a statement transaction.
+**
+** TODO: How should dropping a table be handled? How should renaming a
+** table be handled?
+**
+**
+** Query API Notes
+** ---------------
+**
+** Before coding an UPDATE or DELETE row operation, the code-generator
+** for those two operations needs to know whether or not the operation
+** requires any FK processing and, if so, which columns of the original
+** row are required by the FK processing VDBE code (i.e. if FKs were
+** implemented using triggers, which of the old.* columns would be
+** accessed). No information is required by the code-generator before
+** coding an INSERT operation. The functions used by the UPDATE/DELETE
+** generation code to query for this information are:
+**
+**   sqlite3FkRequired() - Test to see if FK processing is required.
+**   sqlite3FkOldmask()  - Query for the set of required old.* columns.
+**
+**
+** Externally accessible module functions
+** --------------------------------------
+**
+**   sqlite3FkCheck()    - Check for foreign key violations.
+**   sqlite3FkActions()  - Code triggers for ON UPDATE/ON DELETE actions.
+**   sqlite3FkDelete()   - Delete an FKey structure.
+*/
+
+/*
+** VDBE Calling Convention
+** -----------------------
+**
+** Example:
+**
+**   For the following INSERT statement:
+**
+**     CREATE TABLE t1(a, b INTEGER PRIMARY KEY, c);
+**     INSERT INTO t1 VALUES(1, 2, 3.1);
+**
+**   Register (x):        2    (type integer)
+**   Register (x+1):      1    (type integer)
+**   Register (x+2):      NULL (type NULL)
+**   Register (x+3):      3.1  (type real)
+*/
+
+/*
+** A foreign key constraint requires that the key columns in the parent
+** table are collectively subject to a UNIQUE or PRIMARY KEY constraint.
+** Given that pParent is the parent table for foreign key constraint pFKey,
+** search the schema for a unique index on the parent key columns.
+**
+** If successful, zero is returned. If the parent key is an INTEGER PRIMARY
+** KEY column, then output variable *ppIdx is set to NULL. Otherwise, *ppIdx
+** is set to point to the unique index.
+**
+** If the parent key consists of a single column (the foreign key constraint
+** is not a composite foreign key), output variable *paiCol is set to NULL.
+** Otherwise, it is set to point to an allocated array of size N, where
+** N is the number of columns in the parent key. The first element of the
+** array is the index of the child table column that is mapped by the FK
+** constraint to the parent table column stored in the left-most column
+** of index *ppIdx. The second element of the array is the index of the
+** child table column that corresponds to the second left-most column of
+** *ppIdx, and so on.
+**
+** If the required index cannot be found, either because:
+**
+**   1) The named parent key columns do not exist, or
+**
+**   2) The named parent key columns do exist, but are not subject to a
+**      UNIQUE or PRIMARY KEY constraint, or
+**
+**   3) No parent key columns were provided explicitly as part of the
+**      foreign key definition, and the parent table does not have a
+**      PRIMARY KEY, or
+**
+**   4) No parent key columns were provided explicitly as part of the
+**      foreign key definition, and the PRIMARY KEY of the parent table
+**      consists of a different number of columns to the child key in
+**      the child table.
+**
+** then non-zero is returned, and a "foreign key mismatch" error loaded
+** into pParse. If an OOM error occurs, non-zero is returned and the
+** pParse->db->mallocFailed flag is set.
+*/
+SQLITE_PRIVATE int sqlite3FkLocateIndex(
+  Parse *pParse,                  /* Parse context to store any error in */
+  Table *pParent,                 /* Parent table of FK constraint pFKey */
+  FKey *pFKey,                    /* Foreign key to find index for */
+  Index **ppIdx,                  /* OUT: Unique index on parent table */
+  int **paiCol                    /* OUT: Map of index columns in pFKey */
+){
+  Index *pIdx = 0;                    /* Value to return via *ppIdx */
+  int *aiCol = 0;                     /* Value to return via *paiCol */
+  int nCol = pFKey->nCol;             /* Number of columns in parent key */
+  char *zKey = pFKey->aCol[0].zCol;   /* Name of left-most parent key column */
+
+  /* The caller is responsible for zeroing output parameters. */
+  assert( ppIdx && *ppIdx==0 );
+  assert( !paiCol || *paiCol==0 );
+  assert( pParse );
+
+  /* If this is a non-composite (single column) foreign key, check if it
+  ** maps to the INTEGER PRIMARY KEY of table pParent. If so, leave *ppIdx
+  ** and *paiCol set to zero and return early.
+  **
+  ** Otherwise, for a composite foreign key (more than one column), allocate
+  ** space for the aiCol array (returned via output parameter *paiCol).
+  ** Non-composite foreign keys do not require the aiCol array.
+  */
+  if( nCol==1 ){
+    /* The FK maps to the IPK if any of the following are true:
+    **
+    **   1) There is an INTEGER PRIMARY KEY column and the FK is implicitly
+    **      mapped to the primary key of table pParent, or
+    **   2) The FK is explicitly mapped to a column declared as INTEGER
+    **      PRIMARY KEY.
+    */
+    if( pParent->iPKey>=0 ){
+      if( !zKey ) return 0;
+      if( !sqlite3StrICmp(pParent->aCol[pParent->iPKey].zCnName, zKey) ){
+        return 0;
+      }
+    }
+  }else if( paiCol ){
+    assert( nCol>1 );
+    aiCol = (int *)sqlite3DbMallocRawNN(pParse->db, nCol*sizeof(int));
+    if( !aiCol ) return 1;
+    *paiCol = aiCol;
+  }
+
+  for(pIdx=pParent->pIndex; pIdx; pIdx=pIdx->pNext){
+    if( pIdx->nKeyCol==nCol && IsUniqueIndex(pIdx) && pIdx->pPartIdxWhere==0 ){
+      /* pIdx is a UNIQUE index (or a PRIMARY KEY) and has the right number
+      ** of columns. If each indexed column corresponds to a foreign key
+      ** column of pFKey, then this index is a winner.  */
+
+      if( zKey==0 ){
+        /* If zKey is NULL, then this foreign key is implicitly mapped to
+        ** the PRIMARY KEY of table pParent. The PRIMARY KEY index may be
+        ** identified by the test.  */
+        if( IsPrimaryKeyIndex(pIdx) ){
+          if( aiCol ){
+            int i;
+            for(i=0; i<nCol; i++) aiCol[i] = pFKey->aCol[i].iFrom;
+          }
+          break;
+        }
+      }else{
+        /* If zKey is non-NULL, then this foreign key was declared to
+        ** map to an explicit list of columns in table pParent. Check if this
+        ** index matches those columns. Also, check that the index uses
+        ** the default collation sequences for each column. */
+        int i, j;
+        for(i=0; i<nCol; i++){
+          i16 iCol = pIdx->aiColumn[i];     /* Index of column in parent tbl */
+          const char *zDfltColl;            /* Def. collation for column */
+          char *zIdxCol;                    /* Name of indexed column */
+
+          if( iCol<0 ) break; /* No foreign keys against expression indexes */
+
+          /* If the index uses a collation sequence that is different from
+          ** the default collation sequence for the column, this index is
+          ** unusable. Bail out early in this case.  */
+          zDfltColl = sqlite3ColumnColl(&pParent->aCol[iCol]);
+          if( !zDfltColl ) zDfltColl = sqlite3StrBINARY;
+          if( sqlite3StrICmp(pIdx->azColl[i], zDfltColl) ) break;
+
+          zIdxCol = pParent->aCol[iCol].zCnName;
+          for(j=0; j<nCol; j++){
+            if( sqlite3StrICmp(pFKey->aCol[j].zCol, zIdxCol)==0 ){
+              if( aiCol ) aiCol[i] = pFKey->aCol[j].iFrom;
+              break;
+            }
+          }
+          if( j==nCol ) break;
+        }
+        if( i==nCol ) break;      /* pIdx is usable */
+      }
+    }
+  }
+
+  if( !pIdx ){
+    if( !pParse->disableTriggers ){
+      sqlite3ErrorMsg(pParse,
+           "foreign key mismatch - \"%w\" referencing \"%w\"",
+           pFKey->pFrom->zName, pFKey->zTo);
+    }
+    sqlite3DbFree(pParse->db, aiCol);
+    return 1;
+  }
+
+  *ppIdx = pIdx;
+  return 0;
+}
+
+/*
+** This function is called when a row is inserted into or deleted from the
+** child table of foreign key constraint pFKey. If an SQL UPDATE is executed
+** on the child table of pFKey, this function is invoked twice for each row
+** affected - once to "delete" the old row, and then again to "insert" the
+** new row.
+**
+** Each time it is called, this function generates VDBE code to locate the
+** row in the parent table that corresponds to the row being inserted into
+** or deleted from the child table. If the parent row can be found, no
+** special action is taken. Otherwise, if the parent row can *not* be
+** found in the parent table:
+**
+**   Operation | FK type   | Action taken
+**   --------------------------------------------------------------------------
+**   INSERT      immediate   Increment the "immediate constraint counter".
+**
+**   DELETE      immediate   Decrement the "immediate constraint counter".
+**
+**   INSERT      deferred    Increment the "deferred constraint counter".
+**
+**   DELETE      deferred    Decrement the "deferred constraint counter".
+**
+** These operations are identified in the comment at the top of this file
+** (fkey.c) as "I.1" and "D.1".
+*/
+static void fkLookupParent(
+  Parse *pParse,        /* Parse context */
+  int iDb,              /* Index of database housing pTab */
+  Table *pTab,          /* Parent table of FK pFKey */
+  Index *pIdx,          /* Unique index on parent key columns in pTab */
+  FKey *pFKey,          /* Foreign key constraint */
+  int *aiCol,           /* Map from parent key columns to child table columns */
+  int regData,          /* Address of array containing child table row */
+  int nIncr,            /* Increment constraint counter by this */
+  int isIgnore          /* If true, pretend pTab contains all NULL values */
+){
+  int i;                                    /* Iterator variable */
+  Vdbe *v = sqlite3GetVdbe(pParse);         /* Vdbe to add code to */
+  int iCur = pParse->nTab - 1;              /* Cursor number to use */
+  int iOk = sqlite3VdbeMakeLabel(pParse);   /* jump here if parent key found */
+
+  sqlite3VdbeVerifyAbortable(v,
+    (!pFKey->isDeferred
+      && !(pParse->db->flags & SQLITE_DeferFKs)
+      && !pParse->pToplevel
+      && !pParse->isMultiWrite) ? OE_Abort : OE_Ignore);
+
+  /* If nIncr is less than zero, then check at runtime if there are any
+  ** outstanding constraints to resolve. If there are not, there is no need
+  ** to check if deleting this row resolves any outstanding violations.
+  **
+  ** Check if any of the key columns in the child table row are NULL. If
+  ** any are, then the constraint is considered satisfied. No need to
+  ** search for a matching row in the parent table.  */
+  if( nIncr<0 ){
+    sqlite3VdbeAddOp2(v, OP_FkIfZero, pFKey->isDeferred, iOk);
+    VdbeCoverage(v);
+  }
+  for(i=0; i<pFKey->nCol; i++){
+    int iReg = sqlite3TableColumnToStorage(pFKey->pFrom,aiCol[i]) + regData + 1;
+    sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iOk); VdbeCoverage(v);
+  }
+
+  if( isIgnore==0 ){
+    if( pIdx==0 ){
+      /* If pIdx is NULL, then the parent key is the INTEGER PRIMARY KEY
+      ** column of the parent table (table pTab).  */
+      int iMustBeInt;               /* Address of MustBeInt instruction */
+      int regTemp = sqlite3GetTempReg(pParse);
+
+      /* Invoke MustBeInt to coerce the child key value to an integer (i.e.
+      ** apply the affinity of the parent key). If this fails, then there
+      ** is no matching parent key. Before using MustBeInt, make a copy of
+      ** the value. Otherwise, the value inserted into the child key column
+      ** will have INTEGER affinity applied to it, which may not be correct.  */
+      sqlite3VdbeAddOp2(v, OP_SCopy,
+        sqlite3TableColumnToStorage(pFKey->pFrom,aiCol[0])+1+regData, regTemp);
+      iMustBeInt = sqlite3VdbeAddOp2(v, OP_MustBeInt, regTemp, 0);
+      VdbeCoverage(v);
+
+      /* If the parent table is the same as the child table, and we are about
+      ** to increment the constraint-counter (i.e. this is an INSERT operation),
+      ** then check if the row being inserted matches itself. If so, do not
+      ** increment the constraint-counter.  */
+      if( pTab==pFKey->pFrom && nIncr==1 ){
+        sqlite3VdbeAddOp3(v, OP_Eq, regData, iOk, regTemp); VdbeCoverage(v);
+        sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+      }
+
+      sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
+      sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regTemp); VdbeCoverage(v);
+      sqlite3VdbeGoto(v, iOk);
+      sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
+      sqlite3VdbeJumpHere(v, iMustBeInt);
+      sqlite3ReleaseTempReg(pParse, regTemp);
+    }else{
+      int nCol = pFKey->nCol;
+      int regTemp = sqlite3GetTempRange(pParse, nCol);
+
+      sqlite3VdbeAddOp3(v, OP_OpenRead, iCur, pIdx->tnum, iDb);
+      sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+      for(i=0; i<nCol; i++){
+        sqlite3VdbeAddOp2(v, OP_Copy,
+               sqlite3TableColumnToStorage(pFKey->pFrom, aiCol[i])+1+regData,
+               regTemp+i);
+      }
+
+      /* If the parent table is the same as the child table, and we are about
+      ** to increment the constraint-counter (i.e. this is an INSERT operation),
+      ** then check if the row being inserted matches itself. If so, do not
+      ** increment the constraint-counter.
+      **
+      ** If any of the parent-key values are NULL, then the row cannot match
+      ** itself. So set JUMPIFNULL to make sure we do the OP_Found if any
+      ** of the parent-key values are NULL (at this point it is known that
+      ** none of the child key values are).
+      */
+      if( pTab==pFKey->pFrom && nIncr==1 ){
+        int iJump = sqlite3VdbeCurrentAddr(v) + nCol + 1;
+        for(i=0; i<nCol; i++){
+          int iChild = sqlite3TableColumnToStorage(pFKey->pFrom,aiCol[i])
+                              +1+regData;
+          int iParent = 1+regData;
+          iParent += sqlite3TableColumnToStorage(pIdx->pTable,
+                                                 pIdx->aiColumn[i]);
+          assert( pIdx->aiColumn[i]>=0 );
+          assert( aiCol[i]!=pTab->iPKey );
+          if( pIdx->aiColumn[i]==pTab->iPKey ){
+            /* The parent key is a composite key that includes the IPK column */
+            iParent = regData;
+          }
+          sqlite3VdbeAddOp3(v, OP_Ne, iChild, iJump, iParent); VdbeCoverage(v);
+          sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
+        }
+        sqlite3VdbeGoto(v, iOk);
+      }
+
+      sqlite3VdbeAddOp4(v, OP_Affinity, regTemp, nCol, 0,
+                        sqlite3IndexAffinityStr(pParse->db,pIdx), nCol);
+      sqlite3VdbeAddOp4Int(v, OP_Found, iCur, iOk, regTemp, nCol);
+      VdbeCoverage(v);
+      sqlite3ReleaseTempRange(pParse, regTemp, nCol);
+    }
+  }
+
+  if( !pFKey->isDeferred && !(pParse->db->flags & SQLITE_DeferFKs)
+   && !pParse->pToplevel
+   && !pParse->isMultiWrite
+  ){
+    /* Special case: If this is an INSERT statement that will insert exactly
+    ** one row into the table, raise a constraint immediately instead of
+    ** incrementing a counter. This is necessary as the VM code is being
+    ** generated for will not open a statement transaction.  */
+    assert( nIncr==1 );
+    sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_FOREIGNKEY,
+        OE_Abort, 0, P4_STATIC, P5_ConstraintFK);
+  }else{
+    if( nIncr>0 && pFKey->isDeferred==0 ){
+      sqlite3MayAbort(pParse);
+    }
+    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
+  }
+
+  sqlite3VdbeResolveLabel(v, iOk);
+  sqlite3VdbeAddOp1(v, OP_Close, iCur);
+}
+
+
+/*
+** Return an Expr object that refers to a memory register corresponding
+** to column iCol of table pTab.
+**
+** regBase is the first of an array of register that contains the data
+** for pTab.  regBase itself holds the rowid.  regBase+1 holds the first
+** column.  regBase+2 holds the second column, and so forth.
+*/
+static Expr *exprTableRegister(
+  Parse *pParse,     /* Parsing and code generating context */
+  Table *pTab,       /* The table whose content is at r[regBase]... */
+  int regBase,       /* Contents of table pTab */
+  i16 iCol           /* Which column of pTab is desired */
+){
+  Expr *pExpr;
+  Column *pCol;
+  const char *zColl;
+  sqlite3 *db = pParse->db;
+
+  pExpr = sqlite3Expr(db, TK_REGISTER, 0);
+  if( pExpr ){
+    if( iCol>=0 && iCol!=pTab->iPKey ){
+      pCol = &pTab->aCol[iCol];
+      pExpr->iTable = regBase + sqlite3TableColumnToStorage(pTab,iCol) + 1;
+      pExpr->affExpr = pCol->affinity;
+      zColl = sqlite3ColumnColl(pCol);
+      if( zColl==0 ) zColl = db->pDfltColl->zName;
+      pExpr = sqlite3ExprAddCollateString(pParse, pExpr, zColl);
+    }else{
+      pExpr->iTable = regBase;
+      pExpr->affExpr = SQLITE_AFF_INTEGER;
+    }
+  }
+  return pExpr;
+}
+
+/*
+** Return an Expr object that refers to column iCol of table pTab which
+** has cursor iCur.
+*/
+static Expr *exprTableColumn(
+  sqlite3 *db,      /* The database connection */
+  Table *pTab,      /* The table whose column is desired */
+  int iCursor,      /* The open cursor on the table */
+  i16 iCol          /* The column that is wanted */
+){
+  Expr *pExpr = sqlite3Expr(db, TK_COLUMN, 0);
+  if( pExpr ){
+    assert( ExprUseYTab(pExpr) );
+    pExpr->y.pTab = pTab;
+    pExpr->iTable = iCursor;
+    pExpr->iColumn = iCol;
+  }
+  return pExpr;
+}
+
+/*
+** This function is called to generate code executed when a row is deleted
+** from the parent table of foreign key constraint pFKey and, if pFKey is
+** deferred, when a row is inserted into the same table. When generating
+** code for an SQL UPDATE operation, this function may be called twice -
+** once to "delete" the old row and once to "insert" the new row.
+**
+** Parameter nIncr is passed -1 when inserting a row (as this may decrease
+** the number of FK violations in the db) or +1 when deleting one (as this
+** may increase the number of FK constraint problems).
+**
+** The code generated by this function scans through the rows in the child
+** table that correspond to the parent table row being deleted or inserted.
+** For each child row found, one of the following actions is taken:
+**
+**   Operation | FK type   | Action taken
+**   --------------------------------------------------------------------------
+**   DELETE      immediate   Increment the "immediate constraint counter".
+**
+**   INSERT      immediate   Decrement the "immediate constraint counter".
+**
+**   DELETE      deferred    Increment the "deferred constraint counter".
+**
+**   INSERT      deferred    Decrement the "deferred constraint counter".
+**
+** These operations are identified in the comment at the top of this file
+** (fkey.c) as "I.2" and "D.2".
+*/
+static void fkScanChildren(
+  Parse *pParse,                  /* Parse context */
+  SrcList *pSrc,                  /* The child table to be scanned */
+  Table *pTab,                    /* The parent table */
+  Index *pIdx,                    /* Index on parent covering the foreign key */
+  FKey *pFKey,                    /* The foreign key linking pSrc to pTab */
+  int *aiCol,                     /* Map from pIdx cols to child table cols */
+  int regData,                    /* Parent row data starts here */
+  int nIncr                       /* Amount to increment deferred counter by */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  int i;                          /* Iterator variable */
+  Expr *pWhere = 0;               /* WHERE clause to scan with */
+  NameContext sNameContext;       /* Context used to resolve WHERE clause */
+  WhereInfo *pWInfo;              /* Context used by sqlite3WhereXXX() */
+  int iFkIfZero = 0;              /* Address of OP_FkIfZero */
+  Vdbe *v = sqlite3GetVdbe(pParse);
+
+  assert( pIdx==0 || pIdx->pTable==pTab );
+  assert( pIdx==0 || pIdx->nKeyCol==pFKey->nCol );
+  assert( pIdx!=0 || pFKey->nCol==1 );
+  assert( pIdx!=0 || HasRowid(pTab) );
+
+  if( nIncr<0 ){
+    iFkIfZero = sqlite3VdbeAddOp2(v, OP_FkIfZero, pFKey->isDeferred, 0);
+    VdbeCoverage(v);
+  }
+
+  /* Create an Expr object representing an SQL expression like:
+  **
+  **   <parent-key1> = <child-key1> AND <parent-key2> = <child-key2> ...
+  **
+  ** The collation sequence used for the comparison should be that of
+  ** the parent key columns. The affinity of the parent key column should
+  ** be applied to each child key value before the comparison takes place.
+  */
+  for(i=0; i<pFKey->nCol; i++){
+    Expr *pLeft;                  /* Value from parent table row */
+    Expr *pRight;                 /* Column ref to child table */
+    Expr *pEq;                    /* Expression (pLeft = pRight) */
+    i16 iCol;                     /* Index of column in child table */
+    const char *zCol;             /* Name of column in child table */
+
+    iCol = pIdx ? pIdx->aiColumn[i] : -1;
+    pLeft = exprTableRegister(pParse, pTab, regData, iCol);
+    iCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
+    assert( iCol>=0 );
+    zCol = pFKey->pFrom->aCol[iCol].zCnName;
+    pRight = sqlite3Expr(db, TK_ID, zCol);
+    pEq = sqlite3PExpr(pParse, TK_EQ, pLeft, pRight);
+    pWhere = sqlite3ExprAnd(pParse, pWhere, pEq);
+  }
+
+  /* If the child table is the same as the parent table, then add terms
+  ** to the WHERE clause that prevent this entry from being scanned.
+  ** The added WHERE clause terms are like this:
+  **
+  **     $current_rowid!=rowid
+  **     NOT( $current_a==a AND $current_b==b AND ... )
+  **
+  ** The first form is used for rowid tables.  The second form is used
+  ** for WITHOUT ROWID tables. In the second form, the *parent* key is
+  ** (a,b,...). Either the parent or primary key could be used to
+  ** uniquely identify the current row, but the parent key is more convenient
+  ** as the required values have already been loaded into registers
+  ** by the caller.
+  */
+  if( pTab==pFKey->pFrom && nIncr>0 ){
+    Expr *pNe;                    /* Expression (pLeft != pRight) */
+    Expr *pLeft;                  /* Value from parent table row */
+    Expr *pRight;                 /* Column ref to child table */
+    if( HasRowid(pTab) ){
+      pLeft = exprTableRegister(pParse, pTab, regData, -1);
+      pRight = exprTableColumn(db, pTab, pSrc->a[0].iCursor, -1);
+      pNe = sqlite3PExpr(pParse, TK_NE, pLeft, pRight);
+    }else{
+      Expr *pEq, *pAll = 0;
+      assert( pIdx!=0 );
+      for(i=0; i<pIdx->nKeyCol; i++){
+        i16 iCol = pIdx->aiColumn[i];
+        assert( iCol>=0 );
+        pLeft = exprTableRegister(pParse, pTab, regData, iCol);
+        pRight = sqlite3Expr(db, TK_ID, pTab->aCol[iCol].zCnName);
+        pEq = sqlite3PExpr(pParse, TK_IS, pLeft, pRight);
+        pAll = sqlite3ExprAnd(pParse, pAll, pEq);
+      }
+      pNe = sqlite3PExpr(pParse, TK_NOT, pAll, 0);
+    }
+    pWhere = sqlite3ExprAnd(pParse, pWhere, pNe);
+  }
+
+  /* Resolve the references in the WHERE clause. */
+  memset(&sNameContext, 0, sizeof(NameContext));
+  sNameContext.pSrcList = pSrc;
+  sNameContext.pParse = pParse;
+  sqlite3ResolveExprNames(&sNameContext, pWhere);
+
+  /* Create VDBE to loop through the entries in pSrc that match the WHERE
+  ** clause. For each row found, increment either the deferred or immediate
+  ** foreign key constraint counter. */
+  if( pParse->nErr==0 ){
+    pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0, 0);
+    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
+    if( pWInfo ){
+      sqlite3WhereEnd(pWInfo);
+    }
+  }
+
+  /* Clean up the WHERE clause constructed above. */
+  sqlite3ExprDelete(db, pWhere);
+  if( iFkIfZero ){
+    sqlite3VdbeJumpHereOrPopInst(v, iFkIfZero);
+  }
+}
+
+/*
+** This function returns a linked list of FKey objects (connected by
+** FKey.pNextTo) holding all children of table pTab.  For example,
+** given the following schema:
+**
+**   CREATE TABLE t1(a PRIMARY KEY);
+**   CREATE TABLE t2(b REFERENCES t1(a);
+**
+** Calling this function with table "t1" as an argument returns a pointer
+** to the FKey structure representing the foreign key constraint on table
+** "t2". Calling this function with "t2" as the argument would return a
+** NULL pointer (as there are no FK constraints for which t2 is the parent
+** table).
+*/
+SQLITE_PRIVATE FKey *sqlite3FkReferences(Table *pTab){
+  return (FKey *)sqlite3HashFind(&pTab->pSchema->fkeyHash, pTab->zName);
+}
+
+/*
+** The second argument is a Trigger structure allocated by the
+** fkActionTrigger() routine. This function deletes the Trigger structure
+** and all of its sub-components.
+**
+** The Trigger structure or any of its sub-components may be allocated from
+** the lookaside buffer belonging to database handle dbMem.
+*/
+static void fkTriggerDelete(sqlite3 *dbMem, Trigger *p){
+  if( p ){
+    TriggerStep *pStep = p->step_list;
+    sqlite3ExprDelete(dbMem, pStep->pWhere);
+    sqlite3ExprListDelete(dbMem, pStep->pExprList);
+    sqlite3SelectDelete(dbMem, pStep->pSelect);
+    sqlite3ExprDelete(dbMem, p->pWhen);
+    sqlite3DbFree(dbMem, p);
+  }
+}
+
+/*
+** Clear the apTrigger[] cache of CASCADE triggers for all foreign keys
+** in a particular database.  This needs to happen when the schema
+** changes.
+*/
+SQLITE_PRIVATE void sqlite3FkClearTriggerCache(sqlite3 *db, int iDb){
+  HashElem *k;
+  Hash *pHash = &db->aDb[iDb].pSchema->tblHash;
+  for(k=sqliteHashFirst(pHash); k; k=sqliteHashNext(k)){
+    Table *pTab = sqliteHashData(k);
+    FKey *pFKey;
+    if( !IsOrdinaryTable(pTab) ) continue;
+    for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+      fkTriggerDelete(db, pFKey->apTrigger[0]); pFKey->apTrigger[0] = 0;
+      fkTriggerDelete(db, pFKey->apTrigger[1]); pFKey->apTrigger[1] = 0;
+    }
+  }
+}
+
+/*
+** This function is called to generate code that runs when table pTab is
+** being dropped from the database. The SrcList passed as the second argument
+** to this function contains a single entry guaranteed to resolve to
+** table pTab.
+**
+** Normally, no code is required. However, if either
+**
+**   (a) The table is the parent table of a FK constraint, or
+**   (b) The table is the child table of a deferred FK constraint and it is
+**       determined at runtime that there are outstanding deferred FK
+**       constraint violations in the database,
+**
+** then the equivalent of "DELETE FROM <tbl>" is executed before dropping
+** the table from the database. Triggers are disabled while running this
+** DELETE, but foreign key actions are not.
+*/
+SQLITE_PRIVATE void sqlite3FkDropTable(Parse *pParse, SrcList *pName, Table *pTab){
+  sqlite3 *db = pParse->db;
+  if( (db->flags&SQLITE_ForeignKeys) && IsOrdinaryTable(pTab) ){
+    int iSkip = 0;
+    Vdbe *v = sqlite3GetVdbe(pParse);
+
+    assert( v );                  /* VDBE has already been allocated */
+    assert( IsOrdinaryTable(pTab) );
+    if( sqlite3FkReferences(pTab)==0 ){
+      /* Search for a deferred foreign key constraint for which this table
+      ** is the child table. If one cannot be found, return without
+      ** generating any VDBE code. If one can be found, then jump over
+      ** the entire DELETE if there are no outstanding deferred constraints
+      ** when this statement is run.  */
+      FKey *p;
+      for(p=pTab->u.tab.pFKey; p; p=p->pNextFrom){
+        if( p->isDeferred || (db->flags & SQLITE_DeferFKs) ) break;
+      }
+      if( !p ) return;
+      iSkip = sqlite3VdbeMakeLabel(pParse);
+      sqlite3VdbeAddOp2(v, OP_FkIfZero, 1, iSkip); VdbeCoverage(v);
+    }
+
+    pParse->disableTriggers = 1;
+    sqlite3DeleteFrom(pParse, sqlite3SrcListDup(db, pName, 0), 0, 0, 0);
+    pParse->disableTriggers = 0;
+
+    /* If the DELETE has generated immediate foreign key constraint
+    ** violations, halt the VDBE and return an error at this point, before
+    ** any modifications to the schema are made. This is because statement
+    ** transactions are not able to rollback schema changes.
+    **
+    ** If the SQLITE_DeferFKs flag is set, then this is not required, as
+    ** the statement transaction will not be rolled back even if FK
+    ** constraints are violated.
+    */
+    if( (db->flags & SQLITE_DeferFKs)==0 ){
+      sqlite3VdbeVerifyAbortable(v, OE_Abort);
+      sqlite3VdbeAddOp2(v, OP_FkIfZero, 0, sqlite3VdbeCurrentAddr(v)+2);
+      VdbeCoverage(v);
+      sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_FOREIGNKEY,
+          OE_Abort, 0, P4_STATIC, P5_ConstraintFK);
+    }
+
+    if( iSkip ){
+      sqlite3VdbeResolveLabel(v, iSkip);
+    }
+  }
+}
+
+
+/*
+** The second argument points to an FKey object representing a foreign key
+** for which pTab is the child table. An UPDATE statement against pTab
+** is currently being processed. For each column of the table that is
+** actually updated, the corresponding element in the aChange[] array
+** is zero or greater (if a column is unmodified the corresponding element
+** is set to -1). If the rowid column is modified by the UPDATE statement
+** the bChngRowid argument is non-zero.
+**
+** This function returns true if any of the columns that are part of the
+** child key for FK constraint *p are modified.
+*/
+static int fkChildIsModified(
+  Table *pTab,                    /* Table being updated */
+  FKey *p,                        /* Foreign key for which pTab is the child */
+  int *aChange,                   /* Array indicating modified columns */
+  int bChngRowid                  /* True if rowid is modified by this update */
+){
+  int i;
+  for(i=0; i<p->nCol; i++){
+    int iChildKey = p->aCol[i].iFrom;
+    if( aChange[iChildKey]>=0 ) return 1;
+    if( iChildKey==pTab->iPKey && bChngRowid ) return 1;
+  }
+  return 0;
+}
+
+/*
+** The second argument points to an FKey object representing a foreign key
+** for which pTab is the parent table. An UPDATE statement against pTab
+** is currently being processed. For each column of the table that is
+** actually updated, the corresponding element in the aChange[] array
+** is zero or greater (if a column is unmodified the corresponding element
+** is set to -1). If the rowid column is modified by the UPDATE statement
+** the bChngRowid argument is non-zero.
+**
+** This function returns true if any of the columns that are part of the
+** parent key for FK constraint *p are modified.
+*/
+static int fkParentIsModified(
+  Table *pTab,
+  FKey *p,
+  int *aChange,
+  int bChngRowid
+){
+  int i;
+  for(i=0; i<p->nCol; i++){
+    char *zKey = p->aCol[i].zCol;
+    int iKey;
+    for(iKey=0; iKey<pTab->nCol; iKey++){
+      if( aChange[iKey]>=0 || (iKey==pTab->iPKey && bChngRowid) ){
+        Column *pCol = &pTab->aCol[iKey];
+        if( zKey ){
+          if( 0==sqlite3StrICmp(pCol->zCnName, zKey) ) return 1;
+        }else if( pCol->colFlags & COLFLAG_PRIMKEY ){
+          return 1;
+        }
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Return true if the parser passed as the first argument is being
+** used to code a trigger that is really a "SET NULL" action belonging
+** to trigger pFKey.
+*/
+static int isSetNullAction(Parse *pParse, FKey *pFKey){
+  Parse *pTop = sqlite3ParseToplevel(pParse);
+  if( pTop->pTriggerPrg ){
+    Trigger *p = pTop->pTriggerPrg->pTrigger;
+    if( (p==pFKey->apTrigger[0] && pFKey->aAction[0]==OE_SetNull)
+     || (p==pFKey->apTrigger[1] && pFKey->aAction[1]==OE_SetNull)
+    ){
+      assert( (pTop->db->flags & SQLITE_FkNoAction)==0 );
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** This function is called when inserting, deleting or updating a row of
+** table pTab to generate VDBE code to perform foreign key constraint
+** processing for the operation.
+**
+** For a DELETE operation, parameter regOld is passed the index of the
+** first register in an array of (pTab->nCol+1) registers containing the
+** rowid of the row being deleted, followed by each of the column values
+** of the row being deleted, from left to right. Parameter regNew is passed
+** zero in this case.
+**
+** For an INSERT operation, regOld is passed zero and regNew is passed the
+** first register of an array of (pTab->nCol+1) registers containing the new
+** row data.
+**
+** For an UPDATE operation, this function is called twice. Once before
+** the original record is deleted from the table using the calling convention
+** described for DELETE. Then again after the original record is deleted
+** but before the new record is inserted using the INSERT convention.
+*/
+SQLITE_PRIVATE void sqlite3FkCheck(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Row is being deleted from this table */
+  int regOld,                     /* Previous row data is stored here */
+  int regNew,                     /* New row data is stored here */
+  int *aChange,                   /* Array indicating UPDATEd columns (or 0) */
+  int bChngRowid                  /* True if rowid is UPDATEd */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  FKey *pFKey;                    /* Used to iterate through FKs */
+  int iDb;                        /* Index of database containing pTab */
+  const char *zDb;                /* Name of database containing pTab */
+  int isIgnoreErrors = pParse->disableTriggers;
+
+  /* Exactly one of regOld and regNew should be non-zero. */
+  assert( (regOld==0)!=(regNew==0) );
+
+  /* If foreign-keys are disabled, this function is a no-op. */
+  if( (db->flags&SQLITE_ForeignKeys)==0 ) return;
+  if( !IsOrdinaryTable(pTab) ) return;
+
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  zDb = db->aDb[iDb].zDbSName;
+
+  /* Loop through all the foreign key constraints for which pTab is the
+  ** child table (the table that the foreign key definition is part of).  */
+  for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+    Table *pTo;                   /* Parent table of foreign key pFKey */
+    Index *pIdx = 0;              /* Index on key columns in pTo */
+    int *aiFree = 0;
+    int *aiCol;
+    int iCol;
+    int i;
+    int bIgnore = 0;
+
+    if( aChange
+     && sqlite3_stricmp(pTab->zName, pFKey->zTo)!=0
+     && fkChildIsModified(pTab, pFKey, aChange, bChngRowid)==0
+    ){
+      continue;
+    }
+
+    /* Find the parent table of this foreign key. Also find a unique index
+    ** on the parent key columns in the parent table. If either of these
+    ** schema items cannot be located, set an error in pParse and return
+    ** early.  */
+    if( pParse->disableTriggers ){
+      pTo = sqlite3FindTable(db, pFKey->zTo, zDb);
+    }else{
+      pTo = sqlite3LocateTable(pParse, 0, pFKey->zTo, zDb);
+    }
+    if( !pTo || sqlite3FkLocateIndex(pParse, pTo, pFKey, &pIdx, &aiFree) ){
+      assert( isIgnoreErrors==0 || (regOld!=0 && regNew==0) );
+      if( !isIgnoreErrors || db->mallocFailed ) return;
+      if( pTo==0 ){
+        /* If isIgnoreErrors is true, then a table is being dropped. In this
+        ** case SQLite runs a "DELETE FROM xxx" on the table being dropped
+        ** before actually dropping it in order to check FK constraints.
+        ** If the parent table of an FK constraint on the current table is
+        ** missing, behave as if it is empty. i.e. decrement the relevant
+        ** FK counter for each row of the current table with non-NULL keys.
+        */
+        Vdbe *v = sqlite3GetVdbe(pParse);
+        int iJump = sqlite3VdbeCurrentAddr(v) + pFKey->nCol + 1;
+        for(i=0; i<pFKey->nCol; i++){
+          int iFromCol, iReg;
+          iFromCol = pFKey->aCol[i].iFrom;
+          iReg = sqlite3TableColumnToStorage(pFKey->pFrom,iFromCol) + regOld+1;
+          sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iJump); VdbeCoverage(v);
+        }
+        sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, -1);
+      }
+      continue;
+    }
+    assert( pFKey->nCol==1 || (aiFree && pIdx) );
+
+    if( aiFree ){
+      aiCol = aiFree;
+    }else{
+      iCol = pFKey->aCol[0].iFrom;
+      aiCol = &iCol;
+    }
+    for(i=0; i<pFKey->nCol; i++){
+      if( aiCol[i]==pTab->iPKey ){
+        aiCol[i] = -1;
+      }
+      assert( pIdx==0 || pIdx->aiColumn[i]>=0 );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+      /* Request permission to read the parent key columns. If the
+      ** authorization callback returns SQLITE_IGNORE, behave as if any
+      ** values read from the parent table are NULL. */
+      if( db->xAuth ){
+        int rcauth;
+        char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zCnName;
+        rcauth = sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb);
+        bIgnore = (rcauth==SQLITE_IGNORE);
+      }
+#endif
+    }
+
+    /* Take a shared-cache advisory read-lock on the parent table. Allocate
+    ** a cursor to use to search the unique index on the parent key columns
+    ** in the parent table.  */
+    sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
+    pParse->nTab++;
+
+    if( regOld!=0 ){
+      /* A row is being removed from the child table. Search for the parent.
+      ** If the parent does not exist, removing the child row resolves an
+      ** outstanding foreign key constraint violation. */
+      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1, bIgnore);
+    }
+    if( regNew!=0 && !isSetNullAction(pParse, pFKey) ){
+      /* A row is being added to the child table. If a parent row cannot
+      ** be found, adding the child row has violated the FK constraint.
+      **
+      ** If this operation is being performed as part of a trigger program
+      ** that is actually a "SET NULL" action belonging to this very
+      ** foreign key, then omit this scan altogether. As all child key
+      ** values are guaranteed to be NULL, it is not possible for adding
+      ** this row to cause an FK violation.  */
+      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1, bIgnore);
+    }
+
+    sqlite3DbFree(db, aiFree);
+  }
+
+  /* Loop through all the foreign key constraints that refer to this table.
+  ** (the "child" constraints) */
+  for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
+    Index *pIdx = 0;              /* Foreign key index for pFKey */
+    SrcList *pSrc;
+    int *aiCol = 0;
+
+    if( aChange && fkParentIsModified(pTab, pFKey, aChange, bChngRowid)==0 ){
+      continue;
+    }
+
+    if( !pFKey->isDeferred && !(db->flags & SQLITE_DeferFKs)
+     && !pParse->pToplevel && !pParse->isMultiWrite
+    ){
+      assert( regOld==0 && regNew!=0 );
+      /* Inserting a single row into a parent table cannot cause (or fix)
+      ** an immediate foreign key violation. So do nothing in this case.  */
+      continue;
+    }
+
+    if( sqlite3FkLocateIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ){
+      if( !isIgnoreErrors || db->mallocFailed ) return;
+      continue;
+    }
+    assert( aiCol || pFKey->nCol==1 );
+
+    /* Create a SrcList structure containing the child table.  We need the
+    ** child table as a SrcList for sqlite3WhereBegin() */
+    pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
+    if( pSrc ){
+      SrcItem *pItem = pSrc->a;
+      pItem->pSTab = pFKey->pFrom;
+      pItem->zName = pFKey->pFrom->zName;
+      pItem->pSTab->nTabRef++;
+      pItem->iCursor = pParse->nTab++;
+
+      if( regNew!=0 ){
+        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regNew, -1);
+      }
+      if( regOld!=0 ){
+        int eAction = pFKey->aAction[aChange!=0];
+        if( (db->flags & SQLITE_FkNoAction) ) eAction = OE_None;
+
+        fkScanChildren(pParse, pSrc, pTab, pIdx, pFKey, aiCol, regOld, 1);
+        /* If this is a deferred FK constraint, or a CASCADE or SET NULL
+        ** action applies, then any foreign key violations caused by
+        ** removing the parent key will be rectified by the action trigger.
+        ** So do not set the "may-abort" flag in this case.
+        **
+        ** Note 1: If the FK is declared "ON UPDATE CASCADE", then the
+        ** may-abort flag will eventually be set on this statement anyway
+        ** (when this function is called as part of processing the UPDATE
+        ** within the action trigger).
+        **
+        ** Note 2: At first glance it may seem like SQLite could simply omit
+        ** all OP_FkCounter related scans when either CASCADE or SET NULL
+        ** applies. The trouble starts if the CASCADE or SET NULL action
+        ** trigger causes other triggers or action rules attached to the
+        ** child table to fire. In these cases the fk constraint counters
+        ** might be set incorrectly if any OP_FkCounter related scans are
+        ** omitted.  */
+        if( !pFKey->isDeferred && eAction!=OE_Cascade && eAction!=OE_SetNull ){
+          sqlite3MayAbort(pParse);
+        }
+      }
+      pItem->zName = 0;
+      sqlite3SrcListDelete(db, pSrc);
+    }
+    sqlite3DbFree(db, aiCol);
+  }
+}
+
+#define COLUMN_MASK(x) (((x)>31) ? 0xffffffff : ((u32)1<<(x)))
+
+/*
+** This function is called before generating code to update or delete a
+** row contained in table pTab.
+*/
+SQLITE_PRIVATE u32 sqlite3FkOldmask(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab                     /* Table being modified */
+){
+  u32 mask = 0;
+  if( pParse->db->flags&SQLITE_ForeignKeys && IsOrdinaryTable(pTab) ){
+    FKey *p;
+    int i;
+    for(p=pTab->u.tab.pFKey; p; p=p->pNextFrom){
+      for(i=0; i<p->nCol; i++) mask |= COLUMN_MASK(p->aCol[i].iFrom);
+    }
+    for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
+      Index *pIdx = 0;
+      sqlite3FkLocateIndex(pParse, pTab, p, &pIdx, 0);
+      if( pIdx ){
+        for(i=0; i<pIdx->nKeyCol; i++){
+          assert( pIdx->aiColumn[i]>=0 );
+          mask |= COLUMN_MASK(pIdx->aiColumn[i]);
+        }
+      }
+    }
+  }
+  return mask;
+}
+
+
+/*
+** This function is called before generating code to update or delete a
+** row contained in table pTab. If the operation is a DELETE, then
+** parameter aChange is passed a NULL value. For an UPDATE, aChange points
+** to an array of size N, where N is the number of columns in table pTab.
+** If the i'th column is not modified by the UPDATE, then the corresponding
+** entry in the aChange[] array is set to -1. If the column is modified,
+** the value is 0 or greater. Parameter chngRowid is set to true if the
+** UPDATE statement modifies the rowid fields of the table.
+**
+** If any foreign key processing will be required, this function returns
+** non-zero. If there is no foreign key related processing, this function
+** returns zero.
+**
+** For an UPDATE, this function returns 2 if:
+**
+**   * There are any FKs for which pTab is the child and the parent table
+**     and any FK processing at all is required (even of a different FK), or
+**
+**   * the UPDATE modifies one or more parent keys for which the action is
+**     not "NO ACTION" (i.e. is CASCADE, SET DEFAULT or SET NULL).
+**
+** Or, assuming some other foreign key processing is required, 1.
+*/
+SQLITE_PRIVATE int sqlite3FkRequired(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being modified */
+  int *aChange,                   /* Non-NULL for UPDATE operations */
+  int chngRowid                   /* True for UPDATE that affects rowid */
+){
+  int eRet = 1;                   /* Value to return if bHaveFK is true */
+  int bHaveFK = 0;                /* If FK processing is required */
+  if( pParse->db->flags&SQLITE_ForeignKeys && IsOrdinaryTable(pTab) ){
+    if( !aChange ){
+      /* A DELETE operation. Foreign key processing is required if the
+      ** table in question is either the child or parent table for any
+      ** foreign key constraint.  */
+      bHaveFK = (sqlite3FkReferences(pTab) || pTab->u.tab.pFKey);
+    }else{
+      /* This is an UPDATE. Foreign key processing is only required if the
+      ** operation modifies one or more child or parent key columns. */
+      FKey *p;
+
+      /* Check if any child key columns are being modified. */
+      for(p=pTab->u.tab.pFKey; p; p=p->pNextFrom){
+        if( fkChildIsModified(pTab, p, aChange, chngRowid) ){
+          if( 0==sqlite3_stricmp(pTab->zName, p->zTo) ) eRet = 2;
+          bHaveFK = 1;
+        }
+      }
+
+      /* Check if any parent key columns are being modified. */
+      for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
+        if( fkParentIsModified(pTab, p, aChange, chngRowid) ){
+          if( (pParse->db->flags & SQLITE_FkNoAction)==0
+           && p->aAction[1]!=OE_None
+          ){
+            return 2;
+          }
+          bHaveFK = 1;
+        }
+      }
+    }
+  }
+  return bHaveFK ? eRet : 0;
+}
+
+/*
+** This function is called when an UPDATE or DELETE operation is being
+** compiled on table pTab, which is the parent table of foreign-key pFKey.
+** If the current operation is an UPDATE, then the pChanges parameter is
+** passed a pointer to the list of columns being modified. If it is a
+** DELETE, pChanges is passed a NULL pointer.
+**
+** It returns a pointer to a Trigger structure containing a trigger
+** equivalent to the ON UPDATE or ON DELETE action specified by pFKey.
+** If the action is "NO ACTION" then a NULL pointer is returned (these actions
+** require no special handling by the triggers sub-system, code for them is
+** created by fkScanChildren()).
+**
+** For example, if pFKey is the foreign key and pTab is table "p" in
+** the following schema:
+**
+**   CREATE TABLE p(pk PRIMARY KEY);
+**   CREATE TABLE c(ck REFERENCES p ON DELETE CASCADE);
+**
+** then the returned trigger structure is equivalent to:
+**
+**   CREATE TRIGGER ... DELETE ON p BEGIN
+**     DELETE FROM c WHERE ck = old.pk;
+**   END;
+**
+** The returned pointer is cached as part of the foreign key object. It
+** is eventually freed along with the rest of the foreign key object by
+** sqlite3FkDelete().
+*/
+static Trigger *fkActionTrigger(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being updated or deleted from */
+  FKey *pFKey,                    /* Foreign key to get action for */
+  ExprList *pChanges              /* Change-list for UPDATE, NULL for DELETE */
+){
+  sqlite3 *db = pParse->db;       /* Database handle */
+  int action;                     /* One of OE_None, OE_Cascade etc. */
+  Trigger *pTrigger;              /* Trigger definition to return */
+  int iAction = (pChanges!=0);    /* 1 for UPDATE, 0 for DELETE */
+
+  action = pFKey->aAction[iAction];
+  if( (db->flags & SQLITE_FkNoAction) ) action = OE_None;
+  if( action==OE_Restrict && (db->flags & SQLITE_DeferFKs) ){
+    return 0;
+  }
+  pTrigger = pFKey->apTrigger[iAction];
+
+  if( action!=OE_None && !pTrigger ){
+    char const *zFrom;            /* Name of child table */
+    int nFrom;                    /* Length in bytes of zFrom */
+    Index *pIdx = 0;              /* Parent key index for this FK */
+    int *aiCol = 0;               /* child table cols -> parent key cols */
+    TriggerStep *pStep = 0;        /* First (only) step of trigger program */
+    Expr *pWhere = 0;             /* WHERE clause of trigger step */
+    ExprList *pList = 0;          /* Changes list if ON UPDATE CASCADE */
+    Select *pSelect = 0;          /* If RESTRICT, "SELECT RAISE(...)" */
+    int i;                        /* Iterator variable */
+    Expr *pWhen = 0;              /* WHEN clause for the trigger */
+
+    if( sqlite3FkLocateIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ) return 0;
+    assert( aiCol || pFKey->nCol==1 );
+
+    for(i=0; i<pFKey->nCol; i++){
+      Token tOld = { "old", 3 };  /* Literal "old" token */
+      Token tNew = { "new", 3 };  /* Literal "new" token */
+      Token tFromCol;             /* Name of column in child table */
+      Token tToCol;               /* Name of column in parent table */
+      int iFromCol;               /* Idx of column in child table */
+      Expr *pEq;                  /* tFromCol = OLD.tToCol */
+
+      iFromCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
+      assert( iFromCol>=0 );
+      assert( pIdx!=0 || (pTab->iPKey>=0 && pTab->iPKey<pTab->nCol) );
+      assert( pIdx==0 || pIdx->aiColumn[i]>=0 );
+      sqlite3TokenInit(&tToCol,
+                   pTab->aCol[pIdx ? pIdx->aiColumn[i] : pTab->iPKey].zCnName);
+      sqlite3TokenInit(&tFromCol, pFKey->pFrom->aCol[iFromCol].zCnName);
+
+      /* Create the expression "OLD.zToCol = zFromCol". It is important
+      ** that the "OLD.zToCol" term is on the LHS of the = operator, so
+      ** that the affinity and collation sequence associated with the
+      ** parent table are used for the comparison. */
+      pEq = sqlite3PExpr(pParse, TK_EQ,
+          sqlite3PExpr(pParse, TK_DOT,
+            sqlite3ExprAlloc(db, TK_ID, &tOld, 0),
+            sqlite3ExprAlloc(db, TK_ID, &tToCol, 0)),
+          sqlite3ExprAlloc(db, TK_ID, &tFromCol, 0)
+      );
+      pWhere = sqlite3ExprAnd(pParse, pWhere, pEq);
+
+      /* For ON UPDATE, construct the next term of the WHEN clause.
+      ** The final WHEN clause will be like this:
+      **
+      **    WHEN NOT(old.col1 IS new.col1 AND ... AND old.colN IS new.colN)
+      */
+      if( pChanges ){
+        pEq = sqlite3PExpr(pParse, TK_IS,
+            sqlite3PExpr(pParse, TK_DOT,
+              sqlite3ExprAlloc(db, TK_ID, &tOld, 0),
+              sqlite3ExprAlloc(db, TK_ID, &tToCol, 0)),
+            sqlite3PExpr(pParse, TK_DOT,
+              sqlite3ExprAlloc(db, TK_ID, &tNew, 0),
+              sqlite3ExprAlloc(db, TK_ID, &tToCol, 0))
+            );
+        pWhen = sqlite3ExprAnd(pParse, pWhen, pEq);
+      }
+
+      if( action!=OE_Restrict && (action!=OE_Cascade || pChanges) ){
+        Expr *pNew;
+        if( action==OE_Cascade ){
+          pNew = sqlite3PExpr(pParse, TK_DOT,
+            sqlite3ExprAlloc(db, TK_ID, &tNew, 0),
+            sqlite3ExprAlloc(db, TK_ID, &tToCol, 0));
+        }else if( action==OE_SetDflt ){
+          Column *pCol = pFKey->pFrom->aCol + iFromCol;
+          Expr *pDflt;
+          if( pCol->colFlags & COLFLAG_GENERATED ){
+            testcase( pCol->colFlags & COLFLAG_VIRTUAL );
+            testcase( pCol->colFlags & COLFLAG_STORED );
+            pDflt = 0;
+          }else{
+            pDflt = sqlite3ColumnExpr(pFKey->pFrom, pCol);
+          }
+          if( pDflt ){
+            pNew = sqlite3ExprDup(db, pDflt, 0);
+          }else{
+            pNew = sqlite3ExprAlloc(db, TK_NULL, 0, 0);
+          }
+        }else{
+          pNew = sqlite3ExprAlloc(db, TK_NULL, 0, 0);
+        }
+        pList = sqlite3ExprListAppend(pParse, pList, pNew);
+        sqlite3ExprListSetName(pParse, pList, &tFromCol, 0);
+      }
+    }
+    sqlite3DbFree(db, aiCol);
+
+    zFrom = pFKey->pFrom->zName;
+    nFrom = sqlite3Strlen30(zFrom);
+
+    if( action==OE_Restrict ){
+      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      SrcList *pSrc;
+      Expr *pRaise;
+
+      pRaise = sqlite3Expr(db, TK_STRING, "FOREIGN KEY constraint failed"),
+      pRaise = sqlite3PExpr(pParse, TK_RAISE, pRaise, 0);
+      if( pRaise ){
+        pRaise->affExpr = OE_Abort;
+      }
+      pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
+      if( pSrc ){
+        assert( pSrc->nSrc==1 );
+        pSrc->a[0].zName = sqlite3DbStrDup(db, zFrom);
+        assert( pSrc->a[0].fg.fixedSchema==0 && pSrc->a[0].fg.isSubquery==0 );
+        pSrc->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
+      }
+      pSelect = sqlite3SelectNew(pParse,
+          sqlite3ExprListAppend(pParse, 0, pRaise),
+          pSrc,
+          pWhere,
+          0, 0, 0, 0, 0
+      );
+      pWhere = 0;
+    }
+
+    /* Disable lookaside memory allocation */
+    DisableLookaside;
+
+    pTrigger = (Trigger *)sqlite3DbMallocZero(db,
+        sizeof(Trigger) +         /* struct Trigger */
+        sizeof(TriggerStep) +     /* Single step in trigger program */
+        nFrom + 1                 /* Space for pStep->zTarget */
+    );
+    if( pTrigger ){
+      pStep = pTrigger->step_list = (TriggerStep *)&pTrigger[1];
+      pStep->zTarget = (char *)&pStep[1];
+      memcpy((char *)pStep->zTarget, zFrom, nFrom);
+
+      pStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
+      pStep->pExprList = sqlite3ExprListDup(db, pList, EXPRDUP_REDUCE);
+      pStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
+      if( pWhen ){
+        pWhen = sqlite3PExpr(pParse, TK_NOT, pWhen, 0);
+        pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
+      }
+    }
+
+    /* Re-enable the lookaside buffer, if it was disabled earlier. */
+    EnableLookaside;
+
+    sqlite3ExprDelete(db, pWhere);
+    sqlite3ExprDelete(db, pWhen);
+    sqlite3ExprListDelete(db, pList);
+    sqlite3SelectDelete(db, pSelect);
+    if( db->mallocFailed==1 ){
+      fkTriggerDelete(db, pTrigger);
+      return 0;
+    }
+    assert( pStep!=0 );
+    assert( pTrigger!=0 );
+
+    switch( action ){
+      case OE_Restrict:
+        pStep->op = TK_SELECT;
+        break;
+      case OE_Cascade:
+        if( !pChanges ){
+          pStep->op = TK_DELETE;
+          break;
+        }
+        /* no break */ deliberate_fall_through
+      default:
+        pStep->op = TK_UPDATE;
+    }
+    pStep->pTrig = pTrigger;
+    pTrigger->pSchema = pTab->pSchema;
+    pTrigger->pTabSchema = pTab->pSchema;
+    pFKey->apTrigger[iAction] = pTrigger;
+    pTrigger->op = (pChanges ? TK_UPDATE : TK_DELETE);
+  }
+
+  return pTrigger;
+}
+
+/*
+** This function is called when deleting or updating a row to implement
+** any required CASCADE, SET NULL or SET DEFAULT actions.
+*/
+SQLITE_PRIVATE void sqlite3FkActions(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being updated or deleted from */
+  ExprList *pChanges,             /* Change-list for UPDATE, NULL for DELETE */
+  int regOld,                     /* Address of array containing old row */
+  int *aChange,                   /* Array indicating UPDATEd columns (or 0) */
+  int bChngRowid                  /* True if rowid is UPDATEd */
+){
+  /* If foreign-key support is enabled, iterate through all FKs that
+  ** refer to table pTab. If there is an action associated with the FK
+  ** for this operation (either update or delete), invoke the associated
+  ** trigger sub-program.  */
+  if( pParse->db->flags&SQLITE_ForeignKeys ){
+    FKey *pFKey;                  /* Iterator variable */
+    for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
+      if( aChange==0 || fkParentIsModified(pTab, pFKey, aChange, bChngRowid) ){
+        Trigger *pAct = fkActionTrigger(pParse, pTab, pFKey, pChanges);
+        if( pAct ){
+          sqlite3CodeRowTriggerDirect(pParse, pAct, pTab, regOld, OE_Abort, 0);
+        }
+      }
+    }
+  }
+}
+
+#endif /* ifndef SQLITE_OMIT_TRIGGER */
+
+/*
+** Free all memory associated with foreign key definitions attached to
+** table pTab. Remove the deleted foreign keys from the Schema.fkeyHash
+** hash table.
+*/
+SQLITE_PRIVATE void sqlite3FkDelete(sqlite3 *db, Table *pTab){
+  FKey *pFKey;                    /* Iterator variable */
+  FKey *pNext;                    /* Copy of pFKey->pNextFrom */
+
+  assert( IsOrdinaryTable(pTab) );
+  assert( db!=0 );
+  for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pNext){
+    assert( db==0 || sqlite3SchemaMutexHeld(db, 0, pTab->pSchema) );
+
+    /* Remove the FK from the fkeyHash hash table. */
+    if( db->pnBytesFreed==0 ){
+      if( pFKey->pPrevTo ){
+        pFKey->pPrevTo->pNextTo = pFKey->pNextTo;
+      }else{
+        const char *z = (pFKey->pNextTo ? pFKey->pNextTo->zTo : pFKey->zTo);
+        sqlite3HashInsert(&pTab->pSchema->fkeyHash, z, pFKey->pNextTo);
+      }
+      if( pFKey->pNextTo ){
+        pFKey->pNextTo->pPrevTo = pFKey->pPrevTo;
+      }
+    }
+
+    /* EV: R-30323-21917 Each foreign key constraint in SQLite is
+    ** classified as either immediate or deferred.
+    */
+    assert( pFKey->isDeferred==0 || pFKey->isDeferred==1 );
+
+    /* Delete any triggers created to implement actions for this FK. */
+#ifndef SQLITE_OMIT_TRIGGER
+    fkTriggerDelete(db, pFKey->apTrigger[0]);
+    fkTriggerDelete(db, pFKey->apTrigger[1]);
+#endif
+
+    pNext = pFKey->pNextFrom;
+    sqlite3DbFree(db, pFKey);
+  }
+}
+#endif /* ifndef SQLITE_OMIT_FOREIGN_KEY */
+
+/************** End of fkey.c ************************************************/
+/************** Begin file insert.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle INSERT statements in SQLite.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** Generate code that will
+**
+**   (1) acquire a lock for table pTab then
+**   (2) open pTab as cursor iCur.
+**
+** If pTab is a WITHOUT ROWID table, then it is the PRIMARY KEY index
+** for that table that is actually opened.
+*/
+SQLITE_PRIVATE void sqlite3OpenTable(
+  Parse *pParse,  /* Generate code into this VDBE */
+  int iCur,       /* The cursor number of the table */
+  int iDb,        /* The database index in sqlite3.aDb[] */
+  Table *pTab,    /* The table to be opened */
+  int opcode      /* OP_OpenRead or OP_OpenWrite */
+){
+  Vdbe *v;
+  assert( !IsVirtual(pTab) );
+  assert( pParse->pVdbe!=0 );
+  v = pParse->pVdbe;
+  assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
+  if( !pParse->db->noSharedCache ){
+    sqlite3TableLock(pParse, iDb, pTab->tnum,
+                     (opcode==OP_OpenWrite)?1:0, pTab->zName);
+  }
+  if( HasRowid(pTab) ){
+    sqlite3VdbeAddOp4Int(v, opcode, iCur, pTab->tnum, iDb, pTab->nNVCol);
+    VdbeComment((v, "%s", pTab->zName));
+  }else{
+    Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+    assert( pPk!=0 );
+    assert( pPk->tnum==pTab->tnum || CORRUPT_DB );
+    sqlite3VdbeAddOp3(v, opcode, iCur, pPk->tnum, iDb);
+    sqlite3VdbeSetP4KeyInfo(pParse, pPk);
+    VdbeComment((v, "%s", pTab->zName));
+  }
+}
+
+/*
+** Return a pointer to the column affinity string associated with index
+** pIdx. A column affinity string has one character for each column in
+** the table, according to the affinity of the column:
+**
+**  Character      Column affinity
+**  ------------------------------
+**  'A'            BLOB
+**  'B'            TEXT
+**  'C'            NUMERIC
+**  'D'            INTEGER
+**  'F'            REAL
+**
+** An extra 'D' is appended to the end of the string to cover the
+** rowid that appears as the last column in every index.
+**
+** Memory for the buffer containing the column index affinity string
+** is managed along with the rest of the Index structure. It will be
+** released when sqlite3DeleteIndex() is called.
+*/
+static SQLITE_NOINLINE const char *computeIndexAffStr(sqlite3 *db, Index *pIdx){
+  /* The first time a column affinity string for a particular index is
+  ** required, it is allocated and populated here. It is then stored as
+  ** a member of the Index structure for subsequent use.
+  **
+  ** The column affinity string will eventually be deleted by
+  ** sqliteDeleteIndex() when the Index structure itself is cleaned
+  ** up.
+  */
+  int n;
+  Table *pTab = pIdx->pTable;
+  pIdx->zColAff = (char *)sqlite3DbMallocRaw(0, pIdx->nColumn+1);
+  if( !pIdx->zColAff ){
+    sqlite3OomFault(db);
+    return 0;
+  }
+  for(n=0; n<pIdx->nColumn; n++){
+    i16 x = pIdx->aiColumn[n];
+    char aff;
+    if( x>=0 ){
+      aff = pTab->aCol[x].affinity;
+    }else if( x==XN_ROWID ){
+      aff = SQLITE_AFF_INTEGER;
+    }else{
+      assert( x==XN_EXPR );
+      assert( pIdx->bHasExpr );
+      assert( pIdx->aColExpr!=0 );
+      aff = sqlite3ExprAffinity(pIdx->aColExpr->a[n].pExpr);
+    }
+    if( aff<SQLITE_AFF_BLOB ) aff = SQLITE_AFF_BLOB;
+    if( aff>SQLITE_AFF_NUMERIC) aff = SQLITE_AFF_NUMERIC;
+    pIdx->zColAff[n] = aff;
+  }
+  pIdx->zColAff[n] = 0;
+  return pIdx->zColAff;
+}
+SQLITE_PRIVATE const char *sqlite3IndexAffinityStr(sqlite3 *db, Index *pIdx){
+  if( !pIdx->zColAff ) return computeIndexAffStr(db, pIdx);
+  return pIdx->zColAff;
+}
+
+
+/*
+** Compute an affinity string for a table.   Space is obtained
+** from sqlite3DbMalloc().  The caller is responsible for freeing
+** the space when done.
+*/
+SQLITE_PRIVATE char *sqlite3TableAffinityStr(sqlite3 *db, const Table *pTab){
+  char *zColAff;
+  zColAff = (char *)sqlite3DbMallocRaw(db, pTab->nCol+1);
+  if( zColAff ){
+    int i, j;
+    for(i=j=0; i<pTab->nCol; i++){
+      if( (pTab->aCol[i].colFlags & COLFLAG_VIRTUAL)==0 ){
+        zColAff[j++] = pTab->aCol[i].affinity;
+      }
+    }
+    do{
+      zColAff[j--] = 0;
+    }while( j>=0 && zColAff[j]<=SQLITE_AFF_BLOB );
+  }
+  return zColAff;
+}
+
+/*
+** Make changes to the evolving bytecode to do affinity transformations
+** of values that are about to be gathered into a row for table pTab.
+**
+** For ordinary (legacy, non-strict) tables:
+** -----------------------------------------
+**
+** Compute the affinity string for table pTab, if it has not already been
+** computed.  As an optimization, omit trailing SQLITE_AFF_BLOB affinities.
+**
+** If the affinity string is empty (because it was all SQLITE_AFF_BLOB entries
+** which were then optimized out) then this routine becomes a no-op.
+**
+** Otherwise if iReg>0 then code an OP_Affinity opcode that will set the
+** affinities for register iReg and following.  Or if iReg==0,
+** then just set the P4 operand of the previous opcode (which should  be
+** an OP_MakeRecord) to the affinity string.
+**
+** A column affinity string has one character per column:
+**
+**    Character      Column affinity
+**    ---------      ---------------
+**    'A'            BLOB
+**    'B'            TEXT
+**    'C'            NUMERIC
+**    'D'            INTEGER
+**    'E'            REAL
+**
+** For STRICT tables:
+** ------------------
+**
+** Generate an appropriate OP_TypeCheck opcode that will verify the
+** datatypes against the column definitions in pTab.  If iReg==0, that
+** means an OP_MakeRecord opcode has already been generated and should be
+** the last opcode generated.  The new OP_TypeCheck needs to be inserted
+** before the OP_MakeRecord.  The new OP_TypeCheck should use the same
+** register set as the OP_MakeRecord.  If iReg>0 then register iReg is
+** the first of a series of registers that will form the new record.
+** Apply the type checking to that array of registers.
+*/
+SQLITE_PRIVATE void sqlite3TableAffinity(Vdbe *v, Table *pTab, int iReg){
+  int i;
+  char *zColAff;
+  if( pTab->tabFlags & TF_Strict ){
+    if( iReg==0 ){
+      /* Move the previous opcode (which should be OP_MakeRecord) forward
+      ** by one slot and insert a new OP_TypeCheck where the current
+      ** OP_MakeRecord is found */
+      VdbeOp *pPrev;
+      sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+      pPrev = sqlite3VdbeGetLastOp(v);
+      assert( pPrev!=0 );
+      assert( pPrev->opcode==OP_MakeRecord || sqlite3VdbeDb(v)->mallocFailed );
+      pPrev->opcode = OP_TypeCheck;
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, pPrev->p1, pPrev->p2, pPrev->p3);
+    }else{
+      /* Insert an isolated OP_Typecheck */
+      sqlite3VdbeAddOp2(v, OP_TypeCheck, iReg, pTab->nNVCol);
+      sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+    }
+    return;
+  }
+  zColAff = pTab->zColAff;
+  if( zColAff==0 ){
+    zColAff = sqlite3TableAffinityStr(0, pTab);
+    if( !zColAff ){
+      sqlite3OomFault(sqlite3VdbeDb(v));
+      return;
+    }
+    pTab->zColAff = zColAff;
+  }
+  assert( zColAff!=0 );
+  i = sqlite3Strlen30NN(zColAff);
+  if( i ){
+    if( iReg ){
+      sqlite3VdbeAddOp4(v, OP_Affinity, iReg, i, 0, zColAff, i);
+    }else{
+      assert( sqlite3VdbeGetLastOp(v)->opcode==OP_MakeRecord
+              || sqlite3VdbeDb(v)->mallocFailed );
+      sqlite3VdbeChangeP4(v, -1, zColAff, i);
+    }
+  }
+}
+
+/*
+** Return non-zero if the table pTab in database iDb or any of its indices
+** have been opened at any point in the VDBE program. This is used to see if
+** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can
+** run without using a temporary table for the results of the SELECT.
+*/
+static int readsTable(Parse *p, int iDb, Table *pTab){
+  Vdbe *v = sqlite3GetVdbe(p);
+  int i;
+  int iEnd = sqlite3VdbeCurrentAddr(v);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;
+#endif
+
+  for(i=1; i<iEnd; i++){
+    VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
+    assert( pOp!=0 );
+    if( pOp->opcode==OP_OpenRead && pOp->p3==iDb ){
+      Index *pIndex;
+      Pgno tnum = pOp->p2;
+      if( tnum==pTab->tnum ){
+        return 1;
+      }
+      for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
+        if( tnum==pIndex->tnum ){
+          return 1;
+        }
+      }
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pVTab ){
+      assert( pOp->p4.pVtab!=0 );
+      assert( pOp->p4type==P4_VTAB );
+      return 1;
+    }
+#endif
+  }
+  return 0;
+}
+
+/* This walker callback will compute the union of colFlags flags for all
+** referenced columns in a CHECK constraint or generated column expression.
+*/
+static int exprColumnFlagUnion(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_COLUMN && pExpr->iColumn>=0 ){
+    assert( pExpr->iColumn < pWalker->u.pTab->nCol );
+    pWalker->eCode |= pWalker->u.pTab->aCol[pExpr->iColumn].colFlags;
+  }
+  return WRC_Continue;
+}
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+/*
+** All regular columns for table pTab have been puts into registers
+** starting with iRegStore.  The registers that correspond to STORED
+** or VIRTUAL columns have not yet been initialized.  This routine goes
+** back and computes the values for those columns based on the previously
+** computed normal columns.
+*/
+SQLITE_PRIVATE void sqlite3ComputeGeneratedColumns(
+  Parse *pParse,    /* Parsing context */
+  int iRegStore,    /* Register holding the first column */
+  Table *pTab       /* The table */
+){
+  int i;
+  Walker w;
+  Column *pRedo;
+  int eProgress;
+  VdbeOp *pOp;
+
+  assert( pTab->tabFlags & TF_HasGenerated );
+  testcase( pTab->tabFlags & TF_HasVirtual );
+  testcase( pTab->tabFlags & TF_HasStored );
+
+  /* Before computing generated columns, first go through and make sure
+  ** that appropriate affinity has been applied to the regular columns
+  */
+  sqlite3TableAffinity(pParse->pVdbe, pTab, iRegStore);
+  if( (pTab->tabFlags & TF_HasStored)!=0 ){
+    pOp = sqlite3VdbeGetLastOp(pParse->pVdbe);
+    if( pOp->opcode==OP_Affinity ){
+      /* Change the OP_Affinity argument to '@' (NONE) for all stored
+      ** columns.  '@' is the no-op affinity and those columns have not
+      ** yet been computed. */
+      int ii, jj;
+      char *zP4 = pOp->p4.z;
+      assert( zP4!=0 );
+      assert( pOp->p4type==P4_DYNAMIC );
+      for(ii=jj=0; zP4[jj]; ii++){
+        if( pTab->aCol[ii].colFlags & COLFLAG_VIRTUAL ){
+          continue;
+        }
+        if( pTab->aCol[ii].colFlags & COLFLAG_STORED ){
+          zP4[jj] = SQLITE_AFF_NONE;
+        }
+        jj++;
+      }
+    }else if( pOp->opcode==OP_TypeCheck ){
+      /* If an OP_TypeCheck was generated because the table is STRICT,
+      ** then set the P3 operand to indicate that generated columns should
+      ** not be checked */
+      pOp->p3 = 1;
+    }
+  }
+
+  /* Because there can be multiple generated columns that refer to one another,
+  ** this is a two-pass algorithm.  On the first pass, mark all generated
+  ** columns as "not available".
+  */
+  for(i=0; i<pTab->nCol; i++){
+    if( pTab->aCol[i].colFlags & COLFLAG_GENERATED ){
+      testcase( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL );
+      testcase( pTab->aCol[i].colFlags & COLFLAG_STORED );
+      pTab->aCol[i].colFlags |= COLFLAG_NOTAVAIL;
+    }
+  }
+
+  w.u.pTab = pTab;
+  w.xExprCallback = exprColumnFlagUnion;
+  w.xSelectCallback = 0;
+  w.xSelectCallback2 = 0;
+
+  /* On the second pass, compute the value of each NOT-AVAILABLE column.
+  ** Companion code in the TK_COLUMN case of sqlite3ExprCodeTarget() will
+  ** compute dependencies and mark remove the COLSPAN_NOTAVAIL mark, as
+  ** they are needed.
+  */
+  pParse->iSelfTab = -iRegStore;
+  do{
+    eProgress = 0;
+    pRedo = 0;
+    for(i=0; i<pTab->nCol; i++){
+      Column *pCol = pTab->aCol + i;
+      if( (pCol->colFlags & COLFLAG_NOTAVAIL)!=0 ){
+        int x;
+        pCol->colFlags |= COLFLAG_BUSY;
+        w.eCode = 0;
+        sqlite3WalkExpr(&w, sqlite3ColumnExpr(pTab, pCol));
+        pCol->colFlags &= ~COLFLAG_BUSY;
+        if( w.eCode & COLFLAG_NOTAVAIL ){
+          pRedo = pCol;
+          continue;
+        }
+        eProgress = 1;
+        assert( pCol->colFlags & COLFLAG_GENERATED );
+        x = sqlite3TableColumnToStorage(pTab, i) + iRegStore;
+        sqlite3ExprCodeGeneratedColumn(pParse, pTab, pCol, x);
+        pCol->colFlags &= ~COLFLAG_NOTAVAIL;
+      }
+    }
+  }while( pRedo && eProgress );
+  if( pRedo ){
+    sqlite3ErrorMsg(pParse, "generated column loop on \"%s\"", pRedo->zCnName);
+  }
+  pParse->iSelfTab = 0;
+}
+#endif /* SQLITE_OMIT_GENERATED_COLUMNS */
+
+
+#ifndef SQLITE_OMIT_AUTOINCREMENT
+/*
+** Locate or create an AutoincInfo structure associated with table pTab
+** which is in database iDb.  Return the register number for the register
+** that holds the maximum rowid.  Return zero if pTab is not an AUTOINCREMENT
+** table.  (Also return zero when doing a VACUUM since we do not want to
+** update the AUTOINCREMENT counters during a VACUUM.)
+**
+** There is at most one AutoincInfo structure per table even if the
+** same table is autoincremented multiple times due to inserts within
+** triggers.  A new AutoincInfo structure is created if this is the
+** first use of table pTab.  On 2nd and subsequent uses, the original
+** AutoincInfo structure is used.
+**
+** Four consecutive registers are allocated:
+**
+**   (1)  The name of the pTab table.
+**   (2)  The maximum ROWID of pTab.
+**   (3)  The rowid in sqlite_sequence of pTab
+**   (4)  The original value of the max ROWID in pTab, or NULL if none
+**
+** The 2nd register is the one that is returned.  That is all the
+** insert routine needs to know about.
+*/
+static int autoIncBegin(
+  Parse *pParse,      /* Parsing context */
+  int iDb,            /* Index of the database holding pTab */
+  Table *pTab         /* The table we are writing to */
+){
+  int memId = 0;      /* Register holding maximum rowid */
+  assert( pParse->db->aDb[iDb].pSchema!=0 );
+  if( (pTab->tabFlags & TF_Autoincrement)!=0
+   && (pParse->db->mDbFlags & DBFLAG_Vacuum)==0
+  ){
+    Parse *pToplevel = sqlite3ParseToplevel(pParse);
+    AutoincInfo *pInfo;
+    Table *pSeqTab = pParse->db->aDb[iDb].pSchema->pSeqTab;
+
+    /* Verify that the sqlite_sequence table exists and is an ordinary
+    ** rowid table with exactly two columns.
+    ** Ticket d8dc2b3a58cd5dc2918a1d4acb 2018-05-23 */
+    if( pSeqTab==0
+     || !HasRowid(pSeqTab)
+     || NEVER(IsVirtual(pSeqTab))
+     || pSeqTab->nCol!=2
+    ){
+      pParse->nErr++;
+      pParse->rc = SQLITE_CORRUPT_SEQUENCE;
+      return 0;
+    }
+
+    pInfo = pToplevel->pAinc;
+    while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
+    if( pInfo==0 ){
+      pInfo = sqlite3DbMallocRawNN(pParse->db, sizeof(*pInfo));
+      sqlite3ParserAddCleanup(pToplevel, sqlite3DbFree, pInfo);
+      testcase( pParse->earlyCleanup );
+      if( pParse->db->mallocFailed ) return 0;
+      pInfo->pNext = pToplevel->pAinc;
+      pToplevel->pAinc = pInfo;
+      pInfo->pTab = pTab;
+      pInfo->iDb = iDb;
+      pToplevel->nMem++;                  /* Register to hold name of table */
+      pInfo->regCtr = ++pToplevel->nMem;  /* Max rowid register */
+      pToplevel->nMem +=2;       /* Rowid in sqlite_sequence + orig max val */
+    }
+    memId = pInfo->regCtr;
+  }
+  return memId;
+}
+
+/*
+** This routine generates code that will initialize all of the
+** register used by the autoincrement tracker.
+*/
+SQLITE_PRIVATE void sqlite3AutoincrementBegin(Parse *pParse){
+  AutoincInfo *p;            /* Information about an AUTOINCREMENT */
+  sqlite3 *db = pParse->db;  /* The database connection */
+  Db *pDb;                   /* Database only autoinc table */
+  int memId;                 /* Register holding max rowid */
+  Vdbe *v = pParse->pVdbe;   /* VDBE under construction */
+
+  /* This routine is never called during trigger-generation.  It is
+  ** only called from the top-level */
+  assert( pParse->pTriggerTab==0 );
+  assert( sqlite3IsToplevel(pParse) );
+
+  assert( v );   /* We failed long ago if this is not so */
+  for(p = pParse->pAinc; p; p = p->pNext){
+    static const int iLn = VDBE_OFFSET_LINENO(2);
+    static const VdbeOpList autoInc[] = {
+      /* 0  */ {OP_Null,    0,  0, 0},
+      /* 1  */ {OP_Rewind,  0, 10, 0},
+      /* 2  */ {OP_Column,  0,  0, 0},
+      /* 3  */ {OP_Ne,      0,  9, 0},
+      /* 4  */ {OP_Rowid,   0,  0, 0},
+      /* 5  */ {OP_Column,  0,  1, 0},
+      /* 6  */ {OP_AddImm,  0,  0, 0},
+      /* 7  */ {OP_Copy,    0,  0, 0},
+      /* 8  */ {OP_Goto,    0, 11, 0},
+      /* 9  */ {OP_Next,    0,  2, 0},
+      /* 10 */ {OP_Integer, 0,  0, 0},
+      /* 11 */ {OP_Close,   0,  0, 0}
+    };
+    VdbeOp *aOp;
+    pDb = &db->aDb[p->iDb];
+    memId = p->regCtr;
+    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
+    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
+    sqlite3VdbeLoadString(v, memId-1, p->pTab->zName);
+    aOp = sqlite3VdbeAddOpList(v, ArraySize(autoInc), autoInc, iLn);
+    if( aOp==0 ) break;
+    aOp[0].p2 = memId;
+    aOp[0].p3 = memId+2;
+    aOp[2].p3 = memId;
+    aOp[3].p1 = memId-1;
+    aOp[3].p3 = memId;
+    aOp[3].p5 = SQLITE_JUMPIFNULL;
+    aOp[4].p2 = memId+1;
+    aOp[5].p3 = memId;
+    aOp[6].p1 = memId;
+    aOp[7].p2 = memId+2;
+    aOp[7].p1 = memId;
+    aOp[10].p2 = memId;
+    if( pParse->nTab==0 ) pParse->nTab = 1;
+  }
+}
+
+/*
+** Update the maximum rowid for an autoincrement calculation.
+**
+** This routine should be called when the regRowid register holds a
+** new rowid that is about to be inserted.  If that new rowid is
+** larger than the maximum rowid in the memId memory cell, then the
+** memory cell is updated.
+*/
+static void autoIncStep(Parse *pParse, int memId, int regRowid){
+  if( memId>0 ){
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
+  }
+}
+
+/*
+** This routine generates the code needed to write autoincrement
+** maximum rowid values back into the sqlite_sequence register.
+** Every statement that might do an INSERT into an autoincrement
+** table (either directly or through triggers) needs to call this
+** routine just before the "exit" code.
+*/
+static SQLITE_NOINLINE void autoIncrementEnd(Parse *pParse){
+  AutoincInfo *p;
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
+
+  assert( v );
+  for(p = pParse->pAinc; p; p = p->pNext){
+    static const int iLn = VDBE_OFFSET_LINENO(2);
+    static const VdbeOpList autoIncEnd[] = {
+      /* 0 */ {OP_NotNull,     0, 2, 0},
+      /* 1 */ {OP_NewRowid,    0, 0, 0},
+      /* 2 */ {OP_MakeRecord,  0, 2, 0},
+      /* 3 */ {OP_Insert,      0, 0, 0},
+      /* 4 */ {OP_Close,       0, 0, 0}
+    };
+    VdbeOp *aOp;
+    Db *pDb = &db->aDb[p->iDb];
+    int iRec;
+    int memId = p->regCtr;
+
+    iRec = sqlite3GetTempReg(pParse);
+    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
+    sqlite3VdbeAddOp3(v, OP_Le, memId+2, sqlite3VdbeCurrentAddr(v)+7, memId);
+    VdbeCoverage(v);
+    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
+    aOp = sqlite3VdbeAddOpList(v, ArraySize(autoIncEnd), autoIncEnd, iLn);
+    if( aOp==0 ) break;
+    aOp[0].p1 = memId+1;
+    aOp[1].p2 = memId+1;
+    aOp[2].p1 = memId-1;
+    aOp[2].p3 = iRec;
+    aOp[3].p2 = iRec;
+    aOp[3].p3 = memId+1;
+    aOp[3].p5 = OPFLAG_APPEND;
+    sqlite3ReleaseTempReg(pParse, iRec);
+  }
+}
+SQLITE_PRIVATE void sqlite3AutoincrementEnd(Parse *pParse){
+  if( pParse->pAinc ) autoIncrementEnd(pParse);
+}
+#else
+/*
+** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
+** above are all no-ops
+*/
+# define autoIncBegin(A,B,C) (0)
+# define autoIncStep(A,B,C)
+#endif /* SQLITE_OMIT_AUTOINCREMENT */
+
+/*
+** If argument pVal is a Select object returned by an sqlite3MultiValues()
+** that was able to use the co-routine optimization, finish coding the
+** co-routine.
+*/
+SQLITE_PRIVATE void sqlite3MultiValuesEnd(Parse *pParse, Select *pVal){
+  if( ALWAYS(pVal) && pVal->pSrc->nSrc>0 ){
+    SrcItem *pItem = &pVal->pSrc->a[0];
+    assert( (pItem->fg.isSubquery && pItem->u4.pSubq!=0) || pParse->nErr );
+    if( pItem->fg.isSubquery ){
+      sqlite3VdbeEndCoroutine(pParse->pVdbe, pItem->u4.pSubq->regReturn);
+      sqlite3VdbeJumpHere(pParse->pVdbe, pItem->u4.pSubq->addrFillSub - 1);
+    }
+  }
+}
+
+/*
+** Return true if all expressions in the expression-list passed as the
+** only argument are constant.
+*/
+static int exprListIsConstant(Parse *pParse, ExprList *pRow){
+  int ii;
+  for(ii=0; ii<pRow->nExpr; ii++){
+    if( 0==sqlite3ExprIsConstant(pParse, pRow->a[ii].pExpr) ) return 0;
+  }
+  return 1;
+}
+
+/*
+** Return true if all expressions in the expression-list passed as the
+** only argument are both constant and have no affinity.
+*/
+static int exprListIsNoAffinity(Parse *pParse, ExprList *pRow){
+  int ii;
+  if( exprListIsConstant(pParse,pRow)==0 ) return 0;
+  for(ii=0; ii<pRow->nExpr; ii++){
+    Expr *pExpr = pRow->a[ii].pExpr;
+    assert( pExpr->op!=TK_RAISE );
+    assert( pExpr->affExpr==0 );
+    if( 0!=sqlite3ExprAffinity(pExpr) ) return 0;
+  }
+  return 1;
+
+}
+
+/*
+** This function is called by the parser for the second and subsequent
+** rows of a multi-row VALUES clause. Argument pLeft is the part of
+** the VALUES clause already parsed, argument pRow is the vector of values
+** for the new row. The Select object returned represents the complete
+** VALUES clause, including the new row.
+**
+** There are two ways in which this may be achieved - by incremental
+** coding of a co-routine (the "co-routine" method) or by returning a
+** Select object equivalent to the following (the "UNION ALL" method):
+**
+**        "pLeft UNION ALL SELECT pRow"
+**
+** If the VALUES clause contains a lot of rows, this compound Select
+** object may consume a lot of memory.
+**
+** When the co-routine method is used, each row that will be returned
+** by the VALUES clause is coded into part of a co-routine as it is
+** passed to this function. The returned Select object is equivalent to:
+**
+**     SELECT * FROM (
+**       Select object to read co-routine
+**     )
+**
+** The co-routine method is used in most cases. Exceptions are:
+**
+**    a) If the current statement has a WITH clause. This is to avoid
+**       statements like:
+**
+**            WITH cte AS ( VALUES('x'), ('y') ... )
+**            SELECT * FROM cte AS a, cte AS b;
+**
+**       This will not work, as the co-routine uses a hard-coded register
+**       for its OP_Yield instructions, and so it is not possible for two
+**       cursors to iterate through it concurrently.
+**
+**    b) The schema is currently being parsed (i.e. the VALUES clause is part
+**       of a schema item like a VIEW or TRIGGER). In this case there is no VM
+**       being generated when parsing is taking place, and so generating
+**       a co-routine is not possible.
+**
+**    c) There are non-constant expressions in the VALUES clause (e.g.
+**       the VALUES clause is part of a correlated sub-query).
+**
+**    d) One or more of the values in the first row of the VALUES clause
+**       has an affinity (i.e. is a CAST expression). This causes problems
+**       because the complex rules SQLite uses (see function
+**       sqlite3SubqueryColumnTypes() in select.c) to determine the effective
+**       affinity of such a column for all rows require access to all values in
+**       the column simultaneously.
+*/
+SQLITE_PRIVATE Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){
+
+  if( pParse->bHasWith                   /* condition (a) above */
+   || pParse->db->init.busy              /* condition (b) above */
+   || exprListIsConstant(pParse,pRow)==0 /* condition (c) above */
+   || (pLeft->pSrc->nSrc==0 &&
+       exprListIsNoAffinity(pParse,pLeft->pEList)==0) /* condition (d) above */
+   || IN_SPECIAL_PARSE
+  ){
+    /* The co-routine method cannot be used. Fall back to UNION ALL. */
+    Select *pSelect = 0;
+    int f = SF_Values | SF_MultiValue;
+    if( pLeft->pSrc->nSrc ){
+      sqlite3MultiValuesEnd(pParse, pLeft);
+      f = SF_Values;
+    }else if( pLeft->pPrior ){
+      /* In this case set the SF_MultiValue flag only if it was set on pLeft */
+      f = (f & pLeft->selFlags);
+    }
+    pSelect = sqlite3SelectNew(pParse, pRow, 0, 0, 0, 0, 0, f, 0);
+    pLeft->selFlags &= ~SF_MultiValue;
+    if( pSelect ){
+      pSelect->op = TK_ALL;
+      pSelect->pPrior = pLeft;
+      pLeft = pSelect;
+    }
+  }else{
+    SrcItem *p = 0;               /* SrcItem that reads from co-routine */
+
+    if( pLeft->pSrc->nSrc==0 ){
+      /* Co-routine has not yet been started and the special Select object
+      ** that accesses the co-routine has not yet been created. This block
+      ** does both those things. */
+      Vdbe *v = sqlite3GetVdbe(pParse);
+      Select *pRet = sqlite3SelectNew(pParse, 0, 0, 0, 0, 0, 0, 0, 0);
+
+      /* Ensure the database schema has been read. This is to ensure we have
+      ** the correct text encoding.  */
+      if( (pParse->db->mDbFlags & DBFLAG_SchemaKnownOk)==0 ){
+        sqlite3ReadSchema(pParse);
+      }
+
+      if( pRet ){
+        SelectDest dest;
+        Subquery *pSubq;
+        pRet->pSrc->nSrc = 1;
+        pRet->pPrior = pLeft->pPrior;
+        pRet->op = pLeft->op;
+        if( pRet->pPrior ) pRet->selFlags |= SF_Values;
+        pLeft->pPrior = 0;
+        pLeft->op = TK_SELECT;
+        assert( pLeft->pNext==0 );
+        assert( pRet->pNext==0 );
+        p = &pRet->pSrc->a[0];
+        p->fg.viaCoroutine = 1;
+        p->iCursor = -1;
+        assert( !p->fg.isIndexedBy && !p->fg.isTabFunc );
+        p->u1.nRow = 2;
+        if( sqlite3SrcItemAttachSubquery(pParse, p, pLeft, 0) ){
+          pSubq = p->u4.pSubq;
+          pSubq->addrFillSub = sqlite3VdbeCurrentAddr(v) + 1;
+          pSubq->regReturn = ++pParse->nMem;
+          sqlite3VdbeAddOp3(v, OP_InitCoroutine,
+                            pSubq->regReturn, 0, pSubq->addrFillSub);
+          sqlite3SelectDestInit(&dest, SRT_Coroutine, pSubq->regReturn);
+
+          /* Allocate registers for the output of the co-routine. Do so so
+          ** that there are two unused registers immediately before those
+          ** used by the co-routine. This allows the code in sqlite3Insert()
+          ** to use these registers directly, instead of copying the output
+          ** of the co-routine to a separate array for processing.  */
+          dest.iSdst = pParse->nMem + 3;
+          dest.nSdst = pLeft->pEList->nExpr;
+          pParse->nMem += 2 + dest.nSdst;
+
+          pLeft->selFlags |= SF_MultiValue;
+          sqlite3Select(pParse, pLeft, &dest);
+          pSubq->regResult = dest.iSdst;
+          assert( pParse->nErr || dest.iSdst>0 );
+        }
+        pLeft = pRet;
+      }
+    }else{
+      p = &pLeft->pSrc->a[0];
+      assert( !p->fg.isTabFunc && !p->fg.isIndexedBy );
+      p->u1.nRow++;
+    }
+
+    if( pParse->nErr==0 ){
+      Subquery *pSubq;
+      assert( p!=0 );
+      assert( p->fg.isSubquery );
+      pSubq = p->u4.pSubq;
+      assert( pSubq!=0 );
+      assert( pSubq->pSelect!=0 );
+      assert( pSubq->pSelect->pEList!=0 );
+      if( pSubq->pSelect->pEList->nExpr!=pRow->nExpr ){
+        sqlite3SelectWrongNumTermsError(pParse, pSubq->pSelect);
+      }else{
+        sqlite3ExprCodeExprList(pParse, pRow, pSubq->regResult, 0, 0);
+        sqlite3VdbeAddOp1(pParse->pVdbe, OP_Yield, pSubq->regReturn);
+      }
+    }
+    sqlite3ExprListDelete(pParse->db, pRow);
+  }
+
+  return pLeft;
+}
+
+/* Forward declaration */
+static int xferOptimization(
+  Parse *pParse,        /* Parser context */
+  Table *pDest,         /* The table we are inserting into */
+  Select *pSelect,      /* A SELECT statement to use as the data source */
+  int onError,          /* How to handle constraint errors */
+  int iDbDest           /* The database of pDest */
+);
+
+/*
+** This routine is called to handle SQL of the following forms:
+**
+**    insert into TABLE (IDLIST) values(EXPRLIST),(EXPRLIST),...
+**    insert into TABLE (IDLIST) select
+**    insert into TABLE (IDLIST) default values
+**
+** The IDLIST following the table name is always optional.  If omitted,
+** then a list of all (non-hidden) columns for the table is substituted.
+** The IDLIST appears in the pColumn parameter.  pColumn is NULL if IDLIST
+** is omitted.
+**
+** For the pSelect parameter holds the values to be inserted for the
+** first two forms shown above.  A VALUES clause is really just short-hand
+** for a SELECT statement that omits the FROM clause and everything else
+** that follows.  If the pSelect parameter is NULL, that means that the
+** DEFAULT VALUES form of the INSERT statement is intended.
+**
+** The code generated follows one of four templates.  For a simple
+** insert with data coming from a single-row VALUES clause, the code executes
+** once straight down through.  Pseudo-code follows (we call this
+** the "1st template"):
+**
+**         open write cursor to <table> and its indices
+**         put VALUES clause expressions into registers
+**         write the resulting record into <table>
+**         cleanup
+**
+** The three remaining templates assume the statement is of the form
+**
+**   INSERT INTO <table> SELECT ...
+**
+** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
+** in other words if the SELECT pulls all columns from a single table
+** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
+** if <table2> and <table1> are distinct tables but have identical
+** schemas, including all the same indices, then a special optimization
+** is invoked that copies raw records from <table2> over to <table1>.
+** See the xferOptimization() function for the implementation of this
+** template.  This is the 2nd template.
+**
+**         open a write cursor to <table>
+**         open read cursor on <table2>
+**         transfer all records in <table2> over to <table>
+**         close cursors
+**         foreach index on <table>
+**           open a write cursor on the <table> index
+**           open a read cursor on the corresponding <table2> index
+**           transfer all records from the read to the write cursors
+**           close cursors
+**         end foreach
+**
+** The 3rd template is for when the second template does not apply
+** and the SELECT clause does not read from <table> at any time.
+** The generated code follows this template:
+**
+**         X <- A
+**         goto B
+**      A: setup for the SELECT
+**         loop over the rows in the SELECT
+**           load values into registers R..R+n
+**           yield X
+**         end loop
+**         cleanup after the SELECT
+**         end-coroutine X
+**      B: open write cursor to <table> and its indices
+**      C: yield X, at EOF goto D
+**         insert the select result into <table> from R..R+n
+**         goto C
+**      D: cleanup
+**
+** The 4th template is used if the insert statement takes its
+** values from a SELECT but the data is being inserted into a table
+** that is also read as part of the SELECT.  In the third form,
+** we have to use an intermediate table to store the results of
+** the select.  The template is like this:
+**
+**         X <- A
+**         goto B
+**      A: setup for the SELECT
+**         loop over the tables in the SELECT
+**           load value into register R..R+n
+**           yield X
+**         end loop
+**         cleanup after the SELECT
+**         end co-routine R
+**      B: open temp table
+**      L: yield X, at EOF goto M
+**         insert row from R..R+n into temp table
+**         goto L
+**      M: open write cursor to <table> and its indices
+**         rewind temp table
+**      C: loop over rows of intermediate table
+**           transfer values form intermediate table into <table>
+**         end loop
+**      D: cleanup
+*/
+SQLITE_PRIVATE void sqlite3Insert(
+  Parse *pParse,        /* Parser context */
+  SrcList *pTabList,    /* Name of table into which we are inserting */
+  Select *pSelect,      /* A SELECT statement to use as the data source */
+  IdList *pColumn,      /* Column names corresponding to IDLIST, or NULL. */
+  int onError,          /* How to handle constraint errors */
+  Upsert *pUpsert       /* ON CONFLICT clauses for upsert, or NULL */
+){
+  sqlite3 *db;          /* The main database structure */
+  Table *pTab;          /* The table to insert into.  aka TABLE */
+  int i, j;             /* Loop counters */
+  Vdbe *v;              /* Generate code into this virtual machine */
+  Index *pIdx;          /* For looping over indices of the table */
+  int nColumn;          /* Number of columns in the data */
+  int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
+  int iDataCur = 0;     /* VDBE cursor that is the main data repository */
+  int iIdxCur = 0;      /* First index cursor */
+  int ipkColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
+  int endOfLoop;        /* Label for the end of the insertion loop */
+  int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
+  int addrInsTop = 0;   /* Jump to label "D" */
+  int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
+  SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
+  int iDb;              /* Index of database holding TABLE */
+  u8 useTempTable = 0;  /* Store SELECT results in intermediate table */
+  u8 appendFlag = 0;    /* True if the insert is likely to be an append */
+  u8 withoutRowid;      /* 0 for normal table.  1 for WITHOUT ROWID table */
+  u8 bIdListInOrder;    /* True if IDLIST is in table order */
+  ExprList *pList = 0;  /* List of VALUES() to be inserted  */
+  int iRegStore;        /* Register in which to store next column */
+
+  /* Register allocations */
+  int regFromSelect = 0;/* Base register for data coming from SELECT */
+  int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
+  int regRowCount = 0;  /* Memory cell used for the row counter */
+  int regIns;           /* Block of regs holding rowid+data being inserted */
+  int regRowid;         /* registers holding insert rowid */
+  int regData;          /* register holding first column to insert */
+  int *aRegIdx = 0;     /* One register allocated to each index */
+  int *aTabColMap = 0;  /* Mapping from pTab columns to pCol entries */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;                 /* True if attempting to insert into a view */
+  Trigger *pTrigger;          /* List of triggers on pTab, if required */
+  int tmask;                  /* Mask of trigger times */
+#endif
+
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nErr ){
+    goto insert_cleanup;
+  }
+  assert( db->mallocFailed==0 );
+  dest.iSDParm = 0;  /* Suppress a harmless compiler warning */
+
+  /* If the Select object is really just a simple VALUES() list with a
+  ** single row (the common case) then keep that one row of values
+  ** and discard the other (unused) parts of the pSelect object
+  */
+  if( pSelect && (pSelect->selFlags & SF_Values)!=0 && pSelect->pPrior==0 ){
+    pList = pSelect->pEList;
+    pSelect->pEList = 0;
+    sqlite3SelectDelete(db, pSelect);
+    pSelect = 0;
+  }
+
+  /* Locate the table into which we will be inserting new information.
+  */
+  assert( pTabList->nSrc==1 );
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 ){
+    goto insert_cleanup;
+  }
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  assert( iDb<db->nDb );
+  if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0,
+                       db->aDb[iDb].zDbSName) ){
+    goto insert_cleanup;
+  }
+  withoutRowid = !HasRowid(pTab);
+
+  /* Figure out if we have any triggers and if the table being
+  ** inserted into is a view
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
+  isView = IsView(pTab);
+#else
+# define pTrigger 0
+# define tmask 0
+# define isView 0
+#endif
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+  assert( (pTrigger && tmask) || (pTrigger==0 && tmask==0) );
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x10000 ){
+    sqlite3TreeViewLine(0, "In sqlite3Insert() at %s:%d", __FILE__, __LINE__);
+    sqlite3TreeViewInsert(pParse->pWith, pTabList, pColumn, pSelect, pList,
+                          onError, pUpsert, pTrigger);
+  }
+#endif
+
+  /* If pTab is really a view, make sure it has been initialized.
+  ** ViewGetColumnNames() is a no-op if pTab is not a view.
+  */
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto insert_cleanup;
+  }
+
+  /* Cannot insert into a read-only table.
+  */
+  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
+    goto insert_cleanup;
+  }
+
+  /* Allocate a VDBE
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) goto insert_cleanup;
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);
+
+#ifndef SQLITE_OMIT_XFER_OPT
+  /* If the statement is of the form
+  **
+  **       INSERT INTO <table1> SELECT * FROM <table2>;
+  **
+  ** Then special optimizations can be applied that make the transfer
+  ** very fast and which reduce fragmentation of indices.
+  **
+  ** This is the 2nd template.
+  */
+  if( pColumn==0
+   && pSelect!=0
+   && pTrigger==0
+   && xferOptimization(pParse, pTab, pSelect, onError, iDb)
+  ){
+    assert( !pTrigger );
+    assert( pList==0 );
+    goto insert_end;
+  }
+#endif /* SQLITE_OMIT_XFER_OPT */
+
+  /* If this is an AUTOINCREMENT table, look up the sequence number in the
+  ** sqlite_sequence table and store it in memory cell regAutoinc.
+  */
+  regAutoinc = autoIncBegin(pParse, iDb, pTab);
+
+  /* Allocate a block registers to hold the rowid and the values
+  ** for all columns of the new row.
+  */
+  regRowid = regIns = pParse->nMem+1;
+  pParse->nMem += pTab->nCol + 1;
+  if( IsVirtual(pTab) ){
+    regRowid++;
+    pParse->nMem++;
+  }
+  regData = regRowid+1;
+
+  /* If the INSERT statement included an IDLIST term, then make sure
+  ** all elements of the IDLIST really are columns of the table and
+  ** remember the column indices.
+  **
+  ** If the table has an INTEGER PRIMARY KEY column and that column
+  ** is named in the IDLIST, then record in the ipkColumn variable
+  ** the index into IDLIST of the primary key column.  ipkColumn is
+  ** the index of the primary key as it appears in IDLIST, not as
+  ** is appears in the original table.  (The index of the INTEGER
+  ** PRIMARY KEY in the original table is pTab->iPKey.)  After this
+  ** loop, if ipkColumn==(-1), that means that integer primary key
+  ** is unspecified, and hence the table is either WITHOUT ROWID or
+  ** it will automatically generated an integer primary key.
+  **
+  ** bIdListInOrder is true if the columns in IDLIST are in storage
+  ** order.  This enables an optimization that avoids shuffling the
+  ** columns into storage order.  False negatives are harmless,
+  ** but false positives will cause database corruption.
+  */
+  bIdListInOrder = (pTab->tabFlags & (TF_OOOHidden|TF_HasStored))==0;
+  if( pColumn ){
+    aTabColMap = sqlite3DbMallocZero(db, pTab->nCol*sizeof(int));
+    if( aTabColMap==0 ) goto insert_cleanup;
+    for(i=0; i<pColumn->nId; i++){
+      const char *zCName = pColumn->a[i].zName;
+      u8 hName = sqlite3StrIHash(zCName);
+      for(j=0; j<pTab->nCol; j++){
+        if( pTab->aCol[j].hName!=hName ) continue;
+        if( sqlite3StrICmp(zCName, pTab->aCol[j].zCnName)==0 ){
+          if( aTabColMap[j]==0 ) aTabColMap[j] = i+1;
+          if( i!=j ) bIdListInOrder = 0;
+          if( j==pTab->iPKey ){
+            ipkColumn = i;  assert( !withoutRowid );
+          }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+          if( pTab->aCol[j].colFlags & (COLFLAG_STORED|COLFLAG_VIRTUAL) ){
+            sqlite3ErrorMsg(pParse,
+               "cannot INSERT into generated column \"%s\"",
+               pTab->aCol[j].zCnName);
+            goto insert_cleanup;
+          }
+#endif
+          break;
+        }
+      }
+      if( j>=pTab->nCol ){
+        if( sqlite3IsRowid(pColumn->a[i].zName) && !withoutRowid ){
+          ipkColumn = i;
+          bIdListInOrder = 0;
+        }else{
+          sqlite3ErrorMsg(pParse, "table %S has no column named %s",
+              pTabList->a, pColumn->a[i].zName);
+          pParse->checkSchema = 1;
+          goto insert_cleanup;
+        }
+      }
+    }
+  }
+
+  /* Figure out how many columns of data are supplied.  If the data
+  ** is coming from a SELECT statement, then generate a co-routine that
+  ** produces a single row of the SELECT on each invocation.  The
+  ** co-routine is the common header to the 3rd and 4th templates.
+  */
+  if( pSelect ){
+    /* Data is coming from a SELECT or from a multi-row VALUES clause.
+    ** Generate a co-routine to run the SELECT. */
+    int rc;             /* Result code */
+
+    if( pSelect->pSrc->nSrc==1
+     && pSelect->pSrc->a[0].fg.viaCoroutine
+     && pSelect->pPrior==0
+    ){
+      SrcItem *pItem = &pSelect->pSrc->a[0];
+      Subquery *pSubq;
+      assert( pItem->fg.isSubquery );
+      pSubq = pItem->u4.pSubq;
+      dest.iSDParm = pSubq->regReturn;
+      regFromSelect = pSubq->regResult;
+      assert( pSubq->pSelect!=0 );
+      assert( pSubq->pSelect->pEList!=0 );
+      nColumn = pSubq->pSelect->pEList->nExpr;
+      ExplainQueryPlan((pParse, 0, "SCAN %S", pItem));
+      if( bIdListInOrder && nColumn==pTab->nCol ){
+        regData = regFromSelect;
+        regRowid = regData - 1;
+        regIns = regRowid - (IsVirtual(pTab) ? 1 : 0);
+      }
+    }else{
+      int addrTop;        /* Top of the co-routine */
+      int regYield = ++pParse->nMem;
+      addrTop = sqlite3VdbeCurrentAddr(v) + 1;
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
+      dest.iSdst = bIdListInOrder ? regData : 0;
+      dest.nSdst = pTab->nCol;
+      rc = sqlite3Select(pParse, pSelect, &dest);
+      regFromSelect = dest.iSdst;
+      assert( db->pParse==pParse );
+      if( rc || pParse->nErr ) goto insert_cleanup;
+      assert( db->mallocFailed==0 );
+      sqlite3VdbeEndCoroutine(v, regYield);
+      sqlite3VdbeJumpHere(v, addrTop - 1);                       /* label B: */
+      assert( pSelect->pEList );
+      nColumn = pSelect->pEList->nExpr;
+    }
+
+    /* Set useTempTable to TRUE if the result of the SELECT statement
+    ** should be written into a temporary table (template 4).  Set to
+    ** FALSE if each output row of the SELECT can be written directly into
+    ** the destination table (template 3).
+    **
+    ** A temp table must be used if the table being updated is also one
+    ** of the tables being read by the SELECT statement.  Also use a
+    ** temp table in the case of row triggers.
+    */
+    if( pTrigger || readsTable(pParse, iDb, pTab) ){
+      useTempTable = 1;
+    }
+
+    if( useTempTable ){
+      /* Invoke the coroutine to extract information from the SELECT
+      ** and add it to a transient table srcTab.  The code generated
+      ** here is from the 4th template:
+      **
+      **      B: open temp table
+      **      L: yield X, goto M at EOF
+      **         insert row from R..R+n into temp table
+      **         goto L
+      **      M: ...
+      */
+      int regRec;          /* Register to hold packed record */
+      int regTempRowid;    /* Register to hold temp table ROWID */
+      int addrL;           /* Label "L" */
+
+      srcTab = pParse->nTab++;
+      regRec = sqlite3GetTempReg(pParse);
+      regTempRowid = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
+      addrL = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm); VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
+      sqlite3VdbeGoto(v, addrL);
+      sqlite3VdbeJumpHere(v, addrL);
+      sqlite3ReleaseTempReg(pParse, regRec);
+      sqlite3ReleaseTempReg(pParse, regTempRowid);
+    }
+  }else{
+    /* This is the case if the data for the INSERT is coming from a
+    ** single-row VALUES clause
+    */
+    NameContext sNC;
+    memset(&sNC, 0, sizeof(sNC));
+    sNC.pParse = pParse;
+    srcTab = -1;
+    assert( useTempTable==0 );
+    if( pList ){
+      nColumn = pList->nExpr;
+      if( sqlite3ResolveExprListNames(&sNC, pList) ){
+        goto insert_cleanup;
+      }
+    }else{
+      nColumn = 0;
+    }
+  }
+
+  /* If there is no IDLIST term but the table has an integer primary
+  ** key, the set the ipkColumn variable to the integer primary key
+  ** column index in the original table definition.
+  */
+  if( pColumn==0 && nColumn>0 ){
+    ipkColumn = pTab->iPKey;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    if( ipkColumn>=0 && (pTab->tabFlags & TF_HasGenerated)!=0 ){
+      testcase( pTab->tabFlags & TF_HasVirtual );
+      testcase( pTab->tabFlags & TF_HasStored );
+      for(i=ipkColumn-1; i>=0; i--){
+        if( pTab->aCol[i].colFlags & COLFLAG_GENERATED ){
+          testcase( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL );
+          testcase( pTab->aCol[i].colFlags & COLFLAG_STORED );
+          ipkColumn--;
+        }
+      }
+    }
+#endif
+
+    /* Make sure the number of columns in the source data matches the number
+    ** of columns to be inserted into the table.
+    */
+    assert( TF_HasHidden==COLFLAG_HIDDEN );
+    assert( TF_HasGenerated==COLFLAG_GENERATED );
+    assert( COLFLAG_NOINSERT==(COLFLAG_GENERATED|COLFLAG_HIDDEN) );
+    if( (pTab->tabFlags & (TF_HasGenerated|TF_HasHidden))!=0 ){
+      for(i=0; i<pTab->nCol; i++){
+        if( pTab->aCol[i].colFlags & COLFLAG_NOINSERT ) nHidden++;
+      }
+    }
+    if( nColumn!=(pTab->nCol-nHidden) ){
+      sqlite3ErrorMsg(pParse,
+         "table %S has %d columns but %d values were supplied",
+         pTabList->a, pTab->nCol-nHidden, nColumn);
+     goto insert_cleanup;
+    }
+  }
+  if( pColumn!=0 && nColumn!=pColumn->nId ){
+    sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
+    goto insert_cleanup;
+  }
+
+  /* Initialize the count of rows to be inserted
+  */
+  if( (db->flags & SQLITE_CountRows)!=0
+   && !pParse->nested
+   && !pParse->pTriggerTab
+   && !pParse->bReturning
+  ){
+    regRowCount = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
+  }
+
+  /* If this is not a view, open the table and and all indices */
+  if( !isView ){
+    int nIdx;
+    nIdx = sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, -1, 0,
+                                      &iDataCur, &iIdxCur);
+    aRegIdx = sqlite3DbMallocRawNN(db, sizeof(int)*(nIdx+2));
+    if( aRegIdx==0 ){
+      goto insert_cleanup;
+    }
+    for(i=0, pIdx=pTab->pIndex; i<nIdx; pIdx=pIdx->pNext, i++){
+      assert( pIdx );
+      aRegIdx[i] = ++pParse->nMem;
+      pParse->nMem += pIdx->nColumn;
+    }
+    aRegIdx[i] = ++pParse->nMem;  /* Register to store the table record */
+  }
+#ifndef SQLITE_OMIT_UPSERT
+  if( pUpsert ){
+    Upsert *pNx;
+    if( IsVirtual(pTab) ){
+      sqlite3ErrorMsg(pParse, "UPSERT not implemented for virtual table \"%s\"",
+              pTab->zName);
+      goto insert_cleanup;
+    }
+    if( IsView(pTab) ){
+      sqlite3ErrorMsg(pParse, "cannot UPSERT a view");
+      goto insert_cleanup;
+    }
+    if( sqlite3HasExplicitNulls(pParse, pUpsert->pUpsertTarget) ){
+      goto insert_cleanup;
+    }
+    pTabList->a[0].iCursor = iDataCur;
+    pNx = pUpsert;
+    do{
+      pNx->pUpsertSrc = pTabList;
+      pNx->regData = regData;
+      pNx->iDataCur = iDataCur;
+      pNx->iIdxCur = iIdxCur;
+      if( pNx->pUpsertTarget ){
+        if( sqlite3UpsertAnalyzeTarget(pParse, pTabList, pNx, pUpsert) ){
+          goto insert_cleanup;
+        }
+      }
+      pNx = pNx->pNextUpsert;
+    }while( pNx!=0 );
+  }
+#endif
+
+
+  /* This is the top of the main insertion loop */
+  if( useTempTable ){
+    /* This block codes the top of loop only.  The complete loop is the
+    ** following pseudocode (template 4):
+    **
+    **         rewind temp table, if empty goto D
+    **      C: loop over rows of intermediate table
+    **           transfer values form intermediate table into <table>
+    **         end loop
+    **      D: ...
+    */
+    addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab); VdbeCoverage(v);
+    addrCont = sqlite3VdbeCurrentAddr(v);
+  }else if( pSelect ){
+    /* This block codes the top of loop only.  The complete loop is the
+    ** following pseudocode (template 3):
+    **
+    **      C: yield X, at EOF goto D
+    **         insert the select result into <table> from R..R+n
+    **         goto C
+    **      D: ...
+    */
+    sqlite3VdbeReleaseRegisters(pParse, regData, pTab->nCol, 0, 0);
+    addrInsTop = addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
+    VdbeCoverage(v);
+    if( ipkColumn>=0 ){
+      /* tag-20191021-001: If the INTEGER PRIMARY KEY is being generated by the
+      ** SELECT, go ahead and copy the value into the rowid slot now, so that
+      ** the value does not get overwritten by a NULL at tag-20191021-002. */
+      sqlite3VdbeAddOp2(v, OP_Copy, regFromSelect+ipkColumn, regRowid);
+    }
+  }
+
+  /* Compute data for ordinary columns of the new entry.  Values
+  ** are written in storage order into registers starting with regData.
+  ** Only ordinary columns are computed in this loop. The rowid
+  ** (if there is one) is computed later and generated columns are
+  ** computed after the rowid since they might depend on the value
+  ** of the rowid.
+  */
+  nHidden = 0;
+  iRegStore = regData;  assert( regData==regRowid+1 );
+  for(i=0; i<pTab->nCol; i++, iRegStore++){
+    int k;
+    u32 colFlags;
+    assert( i>=nHidden );
+    if( i==pTab->iPKey ){
+      /* tag-20191021-002: References to the INTEGER PRIMARY KEY are filled
+      ** using the rowid. So put a NULL in the IPK slot of the record to avoid
+      ** using excess space.  The file format definition requires this extra
+      ** NULL - we cannot optimize further by skipping the column completely */
+      sqlite3VdbeAddOp1(v, OP_SoftNull, iRegStore);
+      continue;
+    }
+    if( ((colFlags = pTab->aCol[i].colFlags) & COLFLAG_NOINSERT)!=0 ){
+      nHidden++;
+      if( (colFlags & COLFLAG_VIRTUAL)!=0 ){
+        /* Virtual columns do not participate in OP_MakeRecord.  So back up
+        ** iRegStore by one slot to compensate for the iRegStore++ in the
+        ** outer for() loop */
+        iRegStore--;
+        continue;
+      }else if( (colFlags & COLFLAG_STORED)!=0 ){
+        /* Stored columns are computed later.  But if there are BEFORE
+        ** triggers, the slots used for stored columns will be OP_Copy-ed
+        ** to a second block of registers, so the register needs to be
+        ** initialized to NULL to avoid an uninitialized register read */
+        if( tmask & TRIGGER_BEFORE ){
+          sqlite3VdbeAddOp1(v, OP_SoftNull, iRegStore);
+        }
+        continue;
+      }else if( pColumn==0 ){
+        /* Hidden columns that are not explicitly named in the INSERT
+        ** get there default value */
+        sqlite3ExprCodeFactorable(pParse,
+            sqlite3ColumnExpr(pTab, &pTab->aCol[i]),
+            iRegStore);
+        continue;
+      }
+    }
+    if( pColumn ){
+      j = aTabColMap[i];
+      assert( j>=0 && j<=pColumn->nId );
+      if( j==0 ){
+        /* A column not named in the insert column list gets its
+        ** default value */
+        sqlite3ExprCodeFactorable(pParse,
+            sqlite3ColumnExpr(pTab, &pTab->aCol[i]),
+            iRegStore);
+        continue;
+      }
+      k = j - 1;
+    }else if( nColumn==0 ){
+      /* This is INSERT INTO ... DEFAULT VALUES.  Load the default value. */
+      sqlite3ExprCodeFactorable(pParse,
+          sqlite3ColumnExpr(pTab, &pTab->aCol[i]),
+          iRegStore);
+      continue;
+    }else{
+      k = i - nHidden;
+    }
+
+    if( useTempTable ){
+      sqlite3VdbeAddOp3(v, OP_Column, srcTab, k, iRegStore);
+    }else if( pSelect ){
+      if( regFromSelect!=regData ){
+        sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+k, iRegStore);
+      }
+    }else{
+      Expr *pX = pList->a[k].pExpr;
+      int y = sqlite3ExprCodeTarget(pParse, pX, iRegStore);
+      if( y!=iRegStore ){
+        sqlite3VdbeAddOp2(v,
+          ExprHasProperty(pX, EP_Subquery) ? OP_Copy : OP_SCopy, y, iRegStore);
+      }
+    }
+  }
+
+
+  /* Run the BEFORE and INSTEAD OF triggers, if there are any
+  */
+  endOfLoop = sqlite3VdbeMakeLabel(pParse);
+  if( tmask & TRIGGER_BEFORE ){
+    int regCols = sqlite3GetTempRange(pParse, pTab->nCol+1);
+
+    /* build the NEW.* reference row.  Note that if there is an INTEGER
+    ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
+    ** translated into a unique ID for the row.  But on a BEFORE trigger,
+    ** we do not know what the unique ID will be (because the insert has
+    ** not happened yet) so we substitute a rowid of -1
+    */
+    if( ipkColumn<0 ){
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
+    }else{
+      int addr1;
+      assert( !withoutRowid );
+      if( useTempTable ){
+        sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regCols);
+      }else{
+        assert( pSelect==0 );  /* Otherwise useTempTable is true */
+        sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regCols);
+      }
+      addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regCols); VdbeCoverage(v);
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
+      sqlite3VdbeJumpHere(v, addr1);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, regCols); VdbeCoverage(v);
+    }
+
+    /* Copy the new data already generated. */
+    assert( pTab->nNVCol>0 || pParse->nErr>0 );
+    sqlite3VdbeAddOp3(v, OP_Copy, regRowid+1, regCols+1, pTab->nNVCol-1);
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    /* Compute the new value for generated columns after all other
+    ** columns have already been computed.  This must be done after
+    ** computing the ROWID in case one of the generated columns
+    ** refers to the ROWID. */
+    if( pTab->tabFlags & TF_HasGenerated ){
+      testcase( pTab->tabFlags & TF_HasVirtual );
+      testcase( pTab->tabFlags & TF_HasStored );
+      sqlite3ComputeGeneratedColumns(pParse, regCols+1, pTab);
+    }
+#endif
+
+    /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
+    ** do not attempt any conversions before assembling the record.
+    ** If this is a real table, attempt conversions as required by the
+    ** table column affinities.
+    */
+    if( !isView ){
+      sqlite3TableAffinity(v, pTab, regCols+1);
+    }
+
+    /* Fire BEFORE or INSTEAD OF triggers */
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE,
+        pTab, regCols-pTab->nCol-1, onError, endOfLoop);
+
+    sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol+1);
+  }
+
+  if( !isView ){
+    if( IsVirtual(pTab) ){
+      /* The row that the VUpdate opcode will delete: none */
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regIns);
+    }
+    if( ipkColumn>=0 ){
+      /* Compute the new rowid */
+      if( useTempTable ){
+        sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regRowid);
+      }else if( pSelect ){
+        /* Rowid already initialized at tag-20191021-001 */
+      }else{
+        Expr *pIpk = pList->a[ipkColumn].pExpr;
+        if( pIpk->op==TK_NULL && !IsVirtual(pTab) ){
+          sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
+          appendFlag = 1;
+        }else{
+          sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regRowid);
+        }
+      }
+      /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
+      ** to generate a unique primary key value.
+      */
+      if( !appendFlag ){
+        int addr1;
+        if( !IsVirtual(pTab) ){
+          addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid); VdbeCoverage(v);
+          sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
+          sqlite3VdbeJumpHere(v, addr1);
+        }else{
+          addr1 = sqlite3VdbeCurrentAddr(v);
+          sqlite3VdbeAddOp2(v, OP_IsNull, regRowid, addr1+2); VdbeCoverage(v);
+        }
+        sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid); VdbeCoverage(v);
+      }
+    }else if( IsVirtual(pTab) || withoutRowid ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
+      appendFlag = 1;
+    }
+    autoIncStep(pParse, regAutoinc, regRowid);
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    /* Compute the new value for generated columns after all other
+    ** columns have already been computed.  This must be done after
+    ** computing the ROWID in case one of the generated columns
+    ** is derived from the INTEGER PRIMARY KEY. */
+    if( pTab->tabFlags & TF_HasGenerated ){
+      sqlite3ComputeGeneratedColumns(pParse, regRowid+1, pTab);
+    }
+#endif
+
+    /* Generate code to check constraints and generate index keys and
+    ** do the insertion.
+    */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( IsVirtual(pTab) ){
+      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
+      sqlite3VtabMakeWritable(pParse, pTab);
+      sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
+      sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
+      sqlite3MayAbort(pParse);
+    }else
+#endif
+    {
+      int isReplace = 0;/* Set to true if constraints may cause a replace */
+      int bUseSeek;     /* True to use OPFLAG_SEEKRESULT */
+      sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
+          regIns, 0, ipkColumn>=0, onError, endOfLoop, &isReplace, 0, pUpsert
+      );
+      if( db->flags & SQLITE_ForeignKeys ){
+        sqlite3FkCheck(pParse, pTab, 0, regIns, 0, 0);
+      }
+
+      /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
+      ** constraints or (b) there are no triggers and this table is not a
+      ** parent table in a foreign key constraint. It is safe to set the
+      ** flag in the second case as if any REPLACE constraint is hit, an
+      ** OP_Delete or OP_IdxDelete instruction will be executed on each
+      ** cursor that is disturbed. And these instructions both clear the
+      ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
+      ** functionality.  */
+      bUseSeek = (isReplace==0 || !sqlite3VdbeHasSubProgram(v));
+      sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
+          regIns, aRegIdx, 0, appendFlag, bUseSeek
+      );
+    }
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  }else if( pParse->bReturning ){
+    /* If there is a RETURNING clause, populate the rowid register with
+    ** constant value -1, in case one or more of the returned expressions
+    ** refer to the "rowid" of the view.  */
+    sqlite3VdbeAddOp2(v, OP_Integer, -1, regRowid);
+#endif
+  }
+
+  /* Update the count of rows that are inserted
+  */
+  if( regRowCount ){
+    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
+  }
+
+  if( pTrigger ){
+    /* Code AFTER triggers */
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER,
+        pTab, regData-2-pTab->nCol, onError, endOfLoop);
+  }
+
+  /* The bottom of the main insertion loop, if the data source
+  ** is a SELECT statement.
+  */
+  sqlite3VdbeResolveLabel(v, endOfLoop);
+  if( useTempTable ){
+    sqlite3VdbeAddOp2(v, OP_Next, srcTab, addrCont); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addrInsTop);
+    sqlite3VdbeAddOp1(v, OP_Close, srcTab);
+  }else if( pSelect ){
+    sqlite3VdbeGoto(v, addrCont);
+#ifdef SQLITE_DEBUG
+    /* If we are jumping back to an OP_Yield that is preceded by an
+    ** OP_ReleaseReg, set the p5 flag on the OP_Goto so that the
+    ** OP_ReleaseReg will be included in the loop. */
+    if( sqlite3VdbeGetOp(v, addrCont-1)->opcode==OP_ReleaseReg ){
+      assert( sqlite3VdbeGetOp(v, addrCont)->opcode==OP_Yield );
+      sqlite3VdbeChangeP5(v, 1);
+    }
+#endif
+    sqlite3VdbeJumpHere(v, addrInsTop);
+  }
+
+#ifndef SQLITE_OMIT_XFER_OPT
+insert_end:
+#endif /* SQLITE_OMIT_XFER_OPT */
+  /* Update the sqlite_sequence table by storing the content of the
+  ** maximum rowid counter values recorded while inserting into
+  ** autoincrement tables.
+  */
+  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
+    sqlite3AutoincrementEnd(pParse);
+  }
+
+  /*
+  ** Return the number of rows inserted. If this routine is
+  ** generating code because of a call to sqlite3NestedParse(), do not
+  ** invoke the callback function.
+  */
+  if( regRowCount ){
+    sqlite3CodeChangeCount(v, regRowCount, "rows inserted");
+  }
+
+insert_cleanup:
+  sqlite3SrcListDelete(db, pTabList);
+  sqlite3ExprListDelete(db, pList);
+  sqlite3UpsertDelete(db, pUpsert);
+  sqlite3SelectDelete(db, pSelect);
+  if( pColumn ){
+    sqlite3IdListDelete(db, pColumn);
+    sqlite3DbFree(db, aTabColMap);
+  }
+  if( aRegIdx ) sqlite3DbNNFreeNN(db, aRegIdx);
+}
+
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** they may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
+#ifdef tmask
+ #undef tmask
+#endif
+
+/*
+** Meanings of bits in of pWalker->eCode for
+** sqlite3ExprReferencesUpdatedColumn()
+*/
+#define CKCNSTRNT_COLUMN   0x01    /* CHECK constraint uses a changing column */
+#define CKCNSTRNT_ROWID    0x02    /* CHECK constraint references the ROWID */
+
+/* This is the Walker callback from sqlite3ExprReferencesUpdatedColumn().
+*  Set bit 0x01 of pWalker->eCode if pWalker->eCode to 0 and if this
+** expression node references any of the
+** columns that are being modified by an UPDATE statement.
+*/
+static int checkConstraintExprNode(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_COLUMN ){
+    assert( pExpr->iColumn>=0 || pExpr->iColumn==-1 );
+    if( pExpr->iColumn>=0 ){
+      if( pWalker->u.aiCol[pExpr->iColumn]>=0 ){
+        pWalker->eCode |= CKCNSTRNT_COLUMN;
+      }
+    }else{
+      pWalker->eCode |= CKCNSTRNT_ROWID;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** pExpr is a CHECK constraint on a row that is being UPDATE-ed.  The
+** only columns that are modified by the UPDATE are those for which
+** aiChng[i]>=0, and also the ROWID is modified if chngRowid is true.
+**
+** Return true if CHECK constraint pExpr uses any of the
+** changing columns (or the rowid if it is changing).  In other words,
+** return true if this CHECK constraint must be validated for
+** the new row in the UPDATE statement.
+**
+** 2018-09-15: pExpr might also be an expression for an index-on-expressions.
+** The operation of this routine is the same - return true if an only if
+** the expression uses one or more of columns identified by the second and
+** third arguments.
+*/
+SQLITE_PRIVATE int sqlite3ExprReferencesUpdatedColumn(
+  Expr *pExpr,    /* The expression to be checked */
+  int *aiChng,    /* aiChng[x]>=0 if column x changed by the UPDATE */
+  int chngRowid   /* True if UPDATE changes the rowid */
+){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.eCode = 0;
+  w.xExprCallback = checkConstraintExprNode;
+  w.u.aiCol = aiChng;
+  sqlite3WalkExpr(&w, pExpr);
+  if( !chngRowid ){
+    testcase( (w.eCode & CKCNSTRNT_ROWID)!=0 );
+    w.eCode &= ~CKCNSTRNT_ROWID;
+  }
+  testcase( w.eCode==0 );
+  testcase( w.eCode==CKCNSTRNT_COLUMN );
+  testcase( w.eCode==CKCNSTRNT_ROWID );
+  testcase( w.eCode==(CKCNSTRNT_ROWID|CKCNSTRNT_COLUMN) );
+  return w.eCode!=0;
+}
+
+/*
+** The sqlite3GenerateConstraintChecks() routine usually wants to visit
+** the indexes of a table in the order provided in the Table->pIndex list.
+** However, sometimes (rarely - when there is an upsert) it wants to visit
+** the indexes in a different order.  The following data structures accomplish
+** this.
+**
+** The IndexIterator object is used to walk through all of the indexes
+** of a table in either Index.pNext order, or in some other order established
+** by an array of IndexListTerm objects.
+*/
+typedef struct IndexListTerm IndexListTerm;
+typedef struct IndexIterator IndexIterator;
+struct IndexIterator {
+  int eType;    /* 0 for Index.pNext list.  1 for an array of IndexListTerm */
+  int i;        /* Index of the current item from the list */
+  union {
+    struct {    /* Use this object for eType==0: A Index.pNext list */
+      Index *pIdx;   /* The current Index */
+    } lx;
+    struct {    /* Use this object for eType==1; Array of IndexListTerm */
+      int nIdx;               /* Size of the array */
+      IndexListTerm *aIdx;    /* Array of IndexListTerms */
+    } ax;
+  } u;
+};
+
+/* When IndexIterator.eType==1, then each index is an array of instances
+** of the following object
+*/
+struct IndexListTerm {
+  Index *p;  /* The index */
+  int ix;    /* Which entry in the original Table.pIndex list is this index*/
+};
+
+/* Return the first index on the list */
+static Index *indexIteratorFirst(IndexIterator *pIter, int *pIx){
+  assert( pIter->i==0 );
+  if( pIter->eType ){
+    *pIx = pIter->u.ax.aIdx[0].ix;
+    return pIter->u.ax.aIdx[0].p;
+  }else{
+    *pIx = 0;
+    return pIter->u.lx.pIdx;
+  }
+}
+
+/* Return the next index from the list.  Return NULL when out of indexes */
+static Index *indexIteratorNext(IndexIterator *pIter, int *pIx){
+  if( pIter->eType ){
+    int i = ++pIter->i;
+    if( i>=pIter->u.ax.nIdx ){
+      *pIx = i;
+      return 0;
+    }
+    *pIx = pIter->u.ax.aIdx[i].ix;
+    return pIter->u.ax.aIdx[i].p;
+  }else{
+    ++(*pIx);
+    pIter->u.lx.pIdx = pIter->u.lx.pIdx->pNext;
+    return pIter->u.lx.pIdx;
+  }
+}
+
+/*
+** Generate code to do constraint checks prior to an INSERT or an UPDATE
+** on table pTab.
+**
+** The regNewData parameter is the first register in a range that contains
+** the data to be inserted or the data after the update.  There will be
+** pTab->nCol+1 registers in this range.  The first register (the one
+** that regNewData points to) will contain the new rowid, or NULL in the
+** case of a WITHOUT ROWID table.  The second register in the range will
+** contain the content of the first table column.  The third register will
+** contain the content of the second table column.  And so forth.
+**
+** The regOldData parameter is similar to regNewData except that it contains
+** the data prior to an UPDATE rather than afterwards.  regOldData is zero
+** for an INSERT.  This routine can distinguish between UPDATE and INSERT by
+** checking regOldData for zero.
+**
+** For an UPDATE, the pkChng boolean is true if the true primary key (the
+** rowid for a normal table or the PRIMARY KEY for a WITHOUT ROWID table)
+** might be modified by the UPDATE.  If pkChng is false, then the key of
+** the iDataCur content table is guaranteed to be unchanged by the UPDATE.
+**
+** For an INSERT, the pkChng boolean indicates whether or not the rowid
+** was explicitly specified as part of the INSERT statement.  If pkChng
+** is zero, it means that the either rowid is computed automatically or
+** that the table is a WITHOUT ROWID table and has no rowid.  On an INSERT,
+** pkChng will only be true if the INSERT statement provides an integer
+** value for either the rowid column or its INTEGER PRIMARY KEY alias.
+**
+** The code generated by this routine will store new index entries into
+** registers identified by aRegIdx[].  No index entry is created for
+** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
+** the same as the order of indices on the linked list of indices
+** at pTab->pIndex.
+**
+** (2019-05-07) The generated code also creates a new record for the
+** main table, if pTab is a rowid table, and stores that record in the
+** register identified by aRegIdx[nIdx] - in other words in the first
+** entry of aRegIdx[] past the last index.  It is important that the
+** record be generated during constraint checks to avoid affinity changes
+** to the register content that occur after constraint checks but before
+** the new record is inserted.
+**
+** The caller must have already opened writeable cursors on the main
+** table and all applicable indices (that is to say, all indices for which
+** aRegIdx[] is not zero).  iDataCur is the cursor for the main table when
+** inserting or updating a rowid table, or the cursor for the PRIMARY KEY
+** index when operating on a WITHOUT ROWID table.  iIdxCur is the cursor
+** for the first index in the pTab->pIndex list.  Cursors for other indices
+** are at iIdxCur+N for the N-th element of the pTab->pIndex list.
+**
+** This routine also generates code to check constraints.  NOT NULL,
+** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
+** then the appropriate action is performed.  There are five possible
+** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
+**
+**  Constraint type  Action       What Happens
+**  ---------------  ----------   ----------------------------------------
+**  any              ROLLBACK     The current transaction is rolled back and
+**                                sqlite3_step() returns immediately with a
+**                                return code of SQLITE_CONSTRAINT.
+**
+**  any              ABORT        Back out changes from the current command
+**                                only (do not do a complete rollback) then
+**                                cause sqlite3_step() to return immediately
+**                                with SQLITE_CONSTRAINT.
+**
+**  any              FAIL         Sqlite3_step() returns immediately with a
+**                                return code of SQLITE_CONSTRAINT.  The
+**                                transaction is not rolled back and any
+**                                changes to prior rows are retained.
+**
+**  any              IGNORE       The attempt in insert or update the current
+**                                row is skipped, without throwing an error.
+**                                Processing continues with the next row.
+**                                (There is an immediate jump to ignoreDest.)
+**
+**  NOT NULL         REPLACE      The NULL value is replace by the default
+**                                value for that column.  If the default value
+**                                is NULL, the action is the same as ABORT.
+**
+**  UNIQUE           REPLACE      The other row that conflicts with the row
+**                                being inserted is removed.
+**
+**  CHECK            REPLACE      Illegal.  The results in an exception.
+**
+** Which action to take is determined by the overrideError parameter.
+** Or if overrideError==OE_Default, then the pParse->onError parameter
+** is used.  Or if pParse->onError==OE_Default then the onError value
+** for the constraint is used.
+*/
+SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
+  Parse *pParse,       /* The parser context */
+  Table *pTab,         /* The table being inserted or updated */
+  int *aRegIdx,        /* Use register aRegIdx[i] for index i.  0 for unused */
+  int iDataCur,        /* Canonical data cursor (main table or PK index) */
+  int iIdxCur,         /* First index cursor */
+  int regNewData,      /* First register in a range holding values to insert */
+  int regOldData,      /* Previous content.  0 for INSERTs */
+  u8 pkChng,           /* Non-zero if the rowid or PRIMARY KEY changed */
+  u8 overrideError,    /* Override onError to this if not OE_Default */
+  int ignoreDest,      /* Jump to this label on an OE_Ignore resolution */
+  int *pbMayReplace,   /* OUT: Set to true if constraint may cause a replace */
+  int *aiChng,         /* column i is unchanged if aiChng[i]<0 */
+  Upsert *pUpsert      /* ON CONFLICT clauses, if any.  NULL otherwise */
+){
+  Vdbe *v;             /* VDBE under construction */
+  Index *pIdx;         /* Pointer to one of the indices */
+  Index *pPk = 0;      /* The PRIMARY KEY index for WITHOUT ROWID tables */
+  sqlite3 *db;         /* Database connection */
+  int i;               /* loop counter */
+  int ix;              /* Index loop counter */
+  int nCol;            /* Number of columns */
+  int onError;         /* Conflict resolution strategy */
+  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
+  int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
+  Upsert *pUpsertClause = 0;  /* The specific ON CONFLICT clause for pIdx */
+  u8 isUpdate;           /* True if this is an UPDATE operation */
+  u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
+  int upsertIpkReturn = 0; /* Address of Goto at end of IPK uniqueness check */
+  int upsertIpkDelay = 0;  /* Address of Goto to bypass initial IPK check */
+  int ipkTop = 0;        /* Top of the IPK uniqueness check */
+  int ipkBottom = 0;     /* OP_Goto at the end of the IPK uniqueness check */
+  /* Variables associated with retesting uniqueness constraints after
+  ** replace triggers fire have run */
+  int regTrigCnt;       /* Register used to count replace trigger invocations */
+  int addrRecheck = 0;  /* Jump here to recheck all uniqueness constraints */
+  int lblRecheckOk = 0; /* Each recheck jumps to this label if it passes */
+  Trigger *pTrigger;    /* List of DELETE triggers on the table pTab */
+  int nReplaceTrig = 0; /* Number of replace triggers coded */
+  IndexIterator sIdxIter;  /* Index iterator */
+
+  isUpdate = regOldData!=0;
+  db = pParse->db;
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  assert( !IsView(pTab) );  /* This table is not a VIEW */
+  nCol = pTab->nCol;
+
+  /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
+  ** normal rowid tables.  nPkField is the number of key fields in the
+  ** pPk index or 1 for a rowid table.  In other words, nPkField is the
+  ** number of fields in the true primary key of the table. */
+  if( HasRowid(pTab) ){
+    pPk = 0;
+    nPkField = 1;
+  }else{
+    pPk = sqlite3PrimaryKeyIndex(pTab);
+    nPkField = pPk->nKeyCol;
+  }
+
+  /* Record that this module has started */
+  VdbeModuleComment((v, "BEGIN: GenCnstCks(%d,%d,%d,%d,%d)",
+                     iDataCur, iIdxCur, regNewData, regOldData, pkChng));
+
+  /* Test all NOT NULL constraints.
+  */
+  if( pTab->tabFlags & TF_HasNotNull ){
+    int b2ndPass = 0;         /* True if currently running 2nd pass */
+    int nSeenReplace = 0;     /* Number of ON CONFLICT REPLACE operations */
+    int nGenerated = 0;       /* Number of generated columns with NOT NULL */
+    while(1){  /* Make 2 passes over columns. Exit loop via "break" */
+      for(i=0; i<nCol; i++){
+        int iReg;                        /* Register holding column value */
+        Column *pCol = &pTab->aCol[i];   /* The column to check for NOT NULL */
+        int isGenerated;                 /* non-zero if column is generated */
+        onError = pCol->notNull;
+        if( onError==OE_None ) continue; /* No NOT NULL on this column */
+        if( i==pTab->iPKey ){
+          continue;        /* ROWID is never NULL */
+        }
+        isGenerated = pCol->colFlags & COLFLAG_GENERATED;
+        if( isGenerated && !b2ndPass ){
+          nGenerated++;
+          continue;        /* Generated columns processed on 2nd pass */
+        }
+        if( aiChng && aiChng[i]<0 && !isGenerated ){
+          /* Do not check NOT NULL on columns that do not change */
+          continue;
+        }
+        if( overrideError!=OE_Default ){
+          onError = overrideError;
+        }else if( onError==OE_Default ){
+          onError = OE_Abort;
+        }
+        if( onError==OE_Replace ){
+          if( b2ndPass        /* REPLACE becomes ABORT on the 2nd pass */
+           || pCol->iDflt==0  /* REPLACE is ABORT if no DEFAULT value */
+          ){
+            testcase( pCol->colFlags & COLFLAG_VIRTUAL );
+            testcase( pCol->colFlags & COLFLAG_STORED );
+            testcase( pCol->colFlags & COLFLAG_GENERATED );
+            onError = OE_Abort;
+          }else{
+            assert( !isGenerated );
+          }
+        }else if( b2ndPass && !isGenerated ){
+          continue;
+        }
+        assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
+            || onError==OE_Ignore || onError==OE_Replace );
+        testcase( i!=sqlite3TableColumnToStorage(pTab, i) );
+        iReg = sqlite3TableColumnToStorage(pTab, i) + regNewData + 1;
+        switch( onError ){
+          case OE_Replace: {
+            int addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, iReg);
+            VdbeCoverage(v);
+            assert( (pCol->colFlags & COLFLAG_GENERATED)==0 );
+            nSeenReplace++;
+            sqlite3ExprCodeCopy(pParse,
+               sqlite3ColumnExpr(pTab, pCol), iReg);
+            sqlite3VdbeJumpHere(v, addr1);
+            break;
+          }
+          case OE_Abort:
+            sqlite3MayAbort(pParse);
+            /* no break */ deliberate_fall_through
+          case OE_Rollback:
+          case OE_Fail: {
+            char *zMsg = sqlite3MPrintf(db, "%s.%s", pTab->zName,
+                                        pCol->zCnName);
+            testcase( zMsg==0 && db->mallocFailed==0 );
+            sqlite3VdbeAddOp3(v, OP_HaltIfNull, SQLITE_CONSTRAINT_NOTNULL,
+                              onError, iReg);
+            sqlite3VdbeAppendP4(v, zMsg, P4_DYNAMIC);
+            sqlite3VdbeChangeP5(v, P5_ConstraintNotNull);
+            VdbeCoverage(v);
+            break;
+          }
+          default: {
+            assert( onError==OE_Ignore );
+            sqlite3VdbeAddOp2(v, OP_IsNull, iReg, ignoreDest);
+            VdbeCoverage(v);
+            break;
+          }
+        } /* end switch(onError) */
+      } /* end loop i over columns */
+      if( nGenerated==0 && nSeenReplace==0 ){
+        /* If there are no generated columns with NOT NULL constraints
+        ** and no NOT NULL ON CONFLICT REPLACE constraints, then a single
+        ** pass is sufficient */
+        break;
+      }
+      if( b2ndPass ) break;  /* Never need more than 2 passes */
+      b2ndPass = 1;
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+      if( nSeenReplace>0 && (pTab->tabFlags & TF_HasGenerated)!=0 ){
+        /* If any NOT NULL ON CONFLICT REPLACE constraints fired on the
+        ** first pass, recomputed values for all generated columns, as
+        ** those values might depend on columns affected by the REPLACE.
+        */
+        sqlite3ComputeGeneratedColumns(pParse, regNewData+1, pTab);
+      }
+#endif
+    } /* end of 2-pass loop */
+  } /* end if( has-not-null-constraints ) */
+
+  /* Test all CHECK constraints
+  */
+#ifndef SQLITE_OMIT_CHECK
+  if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
+    ExprList *pCheck = pTab->pCheck;
+    pParse->iSelfTab = -(regNewData+1);
+    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
+    for(i=0; i<pCheck->nExpr; i++){
+      int allOk;
+      Expr *pCopy;
+      Expr *pExpr = pCheck->a[i].pExpr;
+      if( aiChng
+       && !sqlite3ExprReferencesUpdatedColumn(pExpr, aiChng, pkChng)
+      ){
+        /* The check constraints do not reference any of the columns being
+        ** updated so there is no point it verifying the check constraint */
+        continue;
+      }
+      if( bAffinityDone==0 ){
+        sqlite3TableAffinity(v, pTab, regNewData+1);
+        bAffinityDone = 1;
+      }
+      allOk = sqlite3VdbeMakeLabel(pParse);
+      sqlite3VdbeVerifyAbortable(v, onError);
+      pCopy = sqlite3ExprDup(db, pExpr, 0);
+      if( !db->mallocFailed ){
+        sqlite3ExprIfTrue(pParse, pCopy, allOk, SQLITE_JUMPIFNULL);
+      }
+      sqlite3ExprDelete(db, pCopy);
+      if( onError==OE_Ignore ){
+        sqlite3VdbeGoto(v, ignoreDest);
+      }else{
+        char *zName = pCheck->a[i].zEName;
+        assert( zName!=0 || pParse->db->mallocFailed );
+        if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-26383-51744 */
+        sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_CHECK,
+                              onError, zName, P4_TRANSIENT,
+                              P5_ConstraintCheck);
+      }
+      sqlite3VdbeResolveLabel(v, allOk);
+    }
+    pParse->iSelfTab = 0;
+  }
+#endif /* !defined(SQLITE_OMIT_CHECK) */
+
+  /* UNIQUE and PRIMARY KEY constraints should be handled in the following
+  ** order:
+  **
+  **   (1)  OE_Update
+  **   (2)  OE_Abort, OE_Fail, OE_Rollback, OE_Ignore
+  **   (3)  OE_Replace
+  **
+  ** OE_Fail and OE_Ignore must happen before any changes are made.
+  ** OE_Update guarantees that only a single row will change, so it
+  ** must happen before OE_Replace.  Technically, OE_Abort and OE_Rollback
+  ** could happen in any order, but they are grouped up front for
+  ** convenience.
+  **
+  ** 2018-08-14: Ticket https://www.sqlite.org/src/info/908f001483982c43
+  ** The order of constraints used to have OE_Update as (2) and OE_Abort
+  ** and so forth as (1). But apparently PostgreSQL checks the OE_Update
+  ** constraint before any others, so it had to be moved.
+  **
+  ** Constraint checking code is generated in this order:
+  **   (A)  The rowid constraint
+  **   (B)  Unique index constraints that do not have OE_Replace as their
+  **        default conflict resolution strategy
+  **   (C)  Unique index that do use OE_Replace by default.
+  **
+  ** The ordering of (2) and (3) is accomplished by making sure the linked
+  ** list of indexes attached to a table puts all OE_Replace indexes last
+  ** in the list.  See sqlite3CreateIndex() for where that happens.
+  */
+  sIdxIter.eType = 0;
+  sIdxIter.i = 0;
+  sIdxIter.u.ax.aIdx = 0;  /* Silence harmless compiler warning */
+  sIdxIter.u.lx.pIdx = pTab->pIndex;
+  if( pUpsert ){
+    if( pUpsert->pUpsertTarget==0 ){
+      /* There is just on ON CONFLICT clause and it has no constraint-target */
+      assert( pUpsert->pNextUpsert==0 );
+      if( pUpsert->isDoUpdate==0 ){
+        /* A single ON CONFLICT DO NOTHING clause, without a constraint-target.
+        ** Make all unique constraint resolution be OE_Ignore */
+        overrideError = OE_Ignore;
+        pUpsert = 0;
+      }else{
+        /* A single ON CONFLICT DO UPDATE.  Make all resolutions OE_Update */
+        overrideError = OE_Update;
+      }
+    }else if( pTab->pIndex!=0 ){
+      /* Otherwise, we'll need to run the IndexListTerm array version of the
+      ** iterator to ensure that all of the ON CONFLICT conditions are
+      ** checked first and in order. */
+      int nIdx, jj;
+      u64 nByte;
+      Upsert *pTerm;
+      u8 *bUsed;
+      for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
+         assert( aRegIdx[nIdx]>0 );
+      }
+      sIdxIter.eType = 1;
+      sIdxIter.u.ax.nIdx = nIdx;
+      nByte = (sizeof(IndexListTerm)+1)*nIdx + nIdx;
+      sIdxIter.u.ax.aIdx = sqlite3DbMallocZero(db, nByte);
+      if( sIdxIter.u.ax.aIdx==0 ) return; /* OOM */
+      bUsed = (u8*)&sIdxIter.u.ax.aIdx[nIdx];
+      pUpsert->pToFree = sIdxIter.u.ax.aIdx;
+      for(i=0, pTerm=pUpsert; pTerm; pTerm=pTerm->pNextUpsert){
+        if( pTerm->pUpsertTarget==0 ) break;
+        if( pTerm->pUpsertIdx==0 ) continue;  /* Skip ON CONFLICT for the IPK */
+        jj = 0;
+        pIdx = pTab->pIndex;
+        while( ALWAYS(pIdx!=0) && pIdx!=pTerm->pUpsertIdx ){
+           pIdx = pIdx->pNext;
+           jj++;
+        }
+        if( bUsed[jj] ) continue; /* Duplicate ON CONFLICT clause ignored */
+        bUsed[jj] = 1;
+        sIdxIter.u.ax.aIdx[i].p = pIdx;
+        sIdxIter.u.ax.aIdx[i].ix = jj;
+        i++;
+      }
+      for(jj=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, jj++){
+        if( bUsed[jj] ) continue;
+        sIdxIter.u.ax.aIdx[i].p = pIdx;
+        sIdxIter.u.ax.aIdx[i].ix = jj;
+        i++;
+      }
+      assert( i==nIdx );
+    }
+  }
+
+  /* Determine if it is possible that triggers (either explicitly coded
+  ** triggers or FK resolution actions) might run as a result of deletes
+  ** that happen when OE_Replace conflict resolution occurs. (Call these
+  ** "replace triggers".)  If any replace triggers run, we will need to
+  ** recheck all of the uniqueness constraints after they have all run.
+  ** But on the recheck, the resolution is OE_Abort instead of OE_Replace.
+  **
+  ** If replace triggers are a possibility, then
+  **
+  **   (1) Allocate register regTrigCnt and initialize it to zero.
+  **       That register will count the number of replace triggers that
+  **       fire.  Constraint recheck only occurs if the number is positive.
+  **   (2) Initialize pTrigger to the list of all DELETE triggers on pTab.
+  **   (3) Initialize addrRecheck and lblRecheckOk
+  **
+  ** The uniqueness rechecking code will create a series of tests to run
+  ** in a second pass.  The addrRecheck and lblRecheckOk variables are
+  ** used to link together these tests which are separated from each other
+  ** in the generate bytecode.
+  */
+  if( (db->flags & (SQLITE_RecTriggers|SQLITE_ForeignKeys))==0 ){
+    /* There are not DELETE triggers nor FK constraints.  No constraint
+    ** rechecks are needed. */
+    pTrigger = 0;
+    regTrigCnt = 0;
+  }else{
+    if( db->flags&SQLITE_RecTriggers ){
+      pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
+      regTrigCnt = pTrigger!=0 || sqlite3FkRequired(pParse, pTab, 0, 0);
+    }else{
+      pTrigger = 0;
+      regTrigCnt = sqlite3FkRequired(pParse, pTab, 0, 0);
+    }
+    if( regTrigCnt ){
+      /* Replace triggers might exist.  Allocate the counter and
+      ** initialize it to zero. */
+      regTrigCnt = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, regTrigCnt);
+      VdbeComment((v, "trigger count"));
+      lblRecheckOk = sqlite3VdbeMakeLabel(pParse);
+      addrRecheck = lblRecheckOk;
+    }
+  }
+
+  /* If rowid is changing, make sure the new rowid does not previously
+  ** exist in the table.
+  */
+  if( pkChng && pPk==0 ){
+    int addrRowidOk = sqlite3VdbeMakeLabel(pParse);
+
+    /* Figure out what action to take in case of a rowid collision */
+    onError = pTab->keyConf;
+    if( overrideError!=OE_Default ){
+      onError = overrideError;
+    }else if( onError==OE_Default ){
+      onError = OE_Abort;
+    }
+
+    /* figure out whether or not upsert applies in this case */
+    if( pUpsert ){
+      pUpsertClause = sqlite3UpsertOfIndex(pUpsert,0);
+      if( pUpsertClause!=0 ){
+        if( pUpsertClause->isDoUpdate==0 ){
+          onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
+        }else{
+          onError = OE_Update;  /* DO UPDATE */
+        }
+      }
+      if( pUpsertClause!=pUpsert ){
+        /* The first ON CONFLICT clause has a conflict target other than
+        ** the IPK.  We have to jump ahead to that first ON CONFLICT clause
+        ** and then come back here and deal with the IPK afterwards */
+        upsertIpkDelay = sqlite3VdbeAddOp0(v, OP_Goto);
+      }
+    }
+
+    /* If the response to a rowid conflict is REPLACE but the response
+    ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
+    ** to defer the running of the rowid conflict checking until after
+    ** the UNIQUE constraints have run.
+    */
+    if( onError==OE_Replace      /* IPK rule is REPLACE */
+     && onError!=overrideError   /* Rules for other constraints are different */
+     && pTab->pIndex             /* There exist other constraints */
+     && !upsertIpkDelay          /* IPK check already deferred by UPSERT */
+    ){
+      ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
+      VdbeComment((v, "defer IPK REPLACE until last"));
+    }
+
+    if( isUpdate ){
+      /* pkChng!=0 does not mean that the rowid has changed, only that
+      ** it might have changed.  Skip the conflict logic below if the rowid
+      ** is unchanged. */
+      sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
+      sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+      VdbeCoverage(v);
+    }
+
+    /* Check to see if the new rowid already exists in the table.  Skip
+    ** the following conflict logic if it does not. */
+    VdbeNoopComment((v, "uniqueness check for ROWID"));
+    sqlite3VdbeVerifyAbortable(v, onError);
+    sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
+    VdbeCoverage(v);
+
+    switch( onError ){
+      default: {
+        onError = OE_Abort;
+        /* no break */ deliberate_fall_through
+      }
+      case OE_Rollback:
+      case OE_Abort:
+      case OE_Fail: {
+        testcase( onError==OE_Rollback );
+        testcase( onError==OE_Abort );
+        testcase( onError==OE_Fail );
+        sqlite3RowidConstraint(pParse, onError, pTab);
+        break;
+      }
+      case OE_Replace: {
+        /* If there are DELETE triggers on this table and the
+        ** recursive-triggers flag is set, call GenerateRowDelete() to
+        ** remove the conflicting row from the table. This will fire
+        ** the triggers and remove both the table and index b-tree entries.
+        **
+        ** Otherwise, if there are no triggers or the recursive-triggers
+        ** flag is not set, but the table has one or more indexes, call
+        ** GenerateRowIndexDelete(). This removes the index b-tree entries
+        ** only. The table b-tree entry will be replaced by the new entry
+        ** when it is inserted.
+        **
+        ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
+        ** also invoke MultiWrite() to indicate that this VDBE may require
+        ** statement rollback (if the statement is aborted after the delete
+        ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
+        ** but being more selective here allows statements like:
+        **
+        **   REPLACE INTO t(rowid) VALUES($newrowid)
+        **
+        ** to run without a statement journal if there are no indexes on the
+        ** table.
+        */
+        if( regTrigCnt ){
+          sqlite3MultiWrite(pParse);
+          sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
+                                   regNewData, 1, 0, OE_Replace, 1, -1);
+          sqlite3VdbeAddOp2(v, OP_AddImm, regTrigCnt, 1); /* incr trigger cnt */
+          nReplaceTrig++;
+        }else{
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+          assert( HasRowid(pTab) );
+          /* This OP_Delete opcode fires the pre-update-hook only. It does
+          ** not modify the b-tree. It is more efficient to let the coming
+          ** OP_Insert replace the existing entry than it is to delete the
+          ** existing entry and then insert a new one. */
+          sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, OPFLAG_ISNOOP);
+          sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+          if( pTab->pIndex ){
+            sqlite3MultiWrite(pParse);
+            sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,-1);
+          }
+        }
+        seenReplace = 1;
+        break;
+      }
+#ifndef SQLITE_OMIT_UPSERT
+      case OE_Update: {
+        sqlite3UpsertDoUpdate(pParse, pUpsert, pTab, 0, iDataCur);
+        /* no break */ deliberate_fall_through
+      }
+#endif
+      case OE_Ignore: {
+        testcase( onError==OE_Ignore );
+        sqlite3VdbeGoto(v, ignoreDest);
+        break;
+      }
+    }
+    sqlite3VdbeResolveLabel(v, addrRowidOk);
+    if( pUpsert && pUpsertClause!=pUpsert ){
+      upsertIpkReturn = sqlite3VdbeAddOp0(v, OP_Goto);
+    }else if( ipkTop ){
+      ipkBottom = sqlite3VdbeAddOp0(v, OP_Goto);
+      sqlite3VdbeJumpHere(v, ipkTop-1);
+    }
+  }
+
+  /* Test all UNIQUE constraints by creating entries for each UNIQUE
+  ** index and making sure that duplicate entries do not already exist.
+  ** Compute the revised record entries for indices as we go.
+  **
+  ** This loop also handles the case of the PRIMARY KEY index for a
+  ** WITHOUT ROWID table.
+  */
+  for(pIdx = indexIteratorFirst(&sIdxIter, &ix);
+      pIdx;
+      pIdx = indexIteratorNext(&sIdxIter, &ix)
+  ){
+    int regIdx;          /* Range of registers holding content for pIdx */
+    int regR;            /* Range of registers holding conflicting PK */
+    int iThisCur;        /* Cursor for this UNIQUE index */
+    int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */
+    int addrConflictCk;  /* First opcode in the conflict check logic */
+
+    if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */
+    if( pUpsert ){
+      pUpsertClause = sqlite3UpsertOfIndex(pUpsert, pIdx);
+      if( upsertIpkDelay && pUpsertClause==pUpsert ){
+        sqlite3VdbeJumpHere(v, upsertIpkDelay);
+      }
+    }
+    addrUniqueOk = sqlite3VdbeMakeLabel(pParse);
+    if( bAffinityDone==0 ){
+      sqlite3TableAffinity(v, pTab, regNewData+1);
+      bAffinityDone = 1;
+    }
+    VdbeNoopComment((v, "prep index %s", pIdx->zName));
+    iThisCur = iIdxCur+ix;
+
+
+    /* Skip partial indices for which the WHERE clause is not true */
+    if( pIdx->pPartIdxWhere ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, aRegIdx[ix]);
+      pParse->iSelfTab = -(regNewData+1);
+      sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, addrUniqueOk,
+                            SQLITE_JUMPIFNULL);
+      pParse->iSelfTab = 0;
+    }
+
+    /* Create a record for this index entry as it should appear after
+    ** the insert or update.  Store that record in the aRegIdx[ix] register
+    */
+    regIdx = aRegIdx[ix]+1;
+    for(i=0; i<pIdx->nColumn; i++){
+      int iField = pIdx->aiColumn[i];
+      int x;
+      if( iField==XN_EXPR ){
+        pParse->iSelfTab = -(regNewData+1);
+        sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[i].pExpr, regIdx+i);
+        pParse->iSelfTab = 0;
+        VdbeComment((v, "%s column %d", pIdx->zName, i));
+      }else if( iField==XN_ROWID || iField==pTab->iPKey ){
+        x = regNewData;
+        sqlite3VdbeAddOp2(v, OP_IntCopy, x, regIdx+i);
+        VdbeComment((v, "rowid"));
+      }else{
+        testcase( sqlite3TableColumnToStorage(pTab, iField)!=iField );
+        x = sqlite3TableColumnToStorage(pTab, iField) + regNewData + 1;
+        sqlite3VdbeAddOp2(v, OP_SCopy, x, regIdx+i);
+        VdbeComment((v, "%s", pTab->aCol[iField].zCnName));
+      }
+    }
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn, aRegIdx[ix]);
+    VdbeComment((v, "for %s", pIdx->zName));
+#ifdef SQLITE_ENABLE_NULL_TRIM
+    if( pIdx->idxType==SQLITE_IDXTYPE_PRIMARYKEY ){
+      sqlite3SetMakeRecordP5(v, pIdx->pTable);
+    }
+#endif
+    sqlite3VdbeReleaseRegisters(pParse, regIdx, pIdx->nColumn, 0, 0);
+
+    /* In an UPDATE operation, if this index is the PRIMARY KEY index
+    ** of a WITHOUT ROWID table and there has been no change the
+    ** primary key, then no collision is possible.  The collision detection
+    ** logic below can all be skipped. */
+    if( isUpdate && pPk==pIdx && pkChng==0 ){
+      sqlite3VdbeResolveLabel(v, addrUniqueOk);
+      continue;
+    }
+
+    /* Find out what action to take in case there is a uniqueness conflict */
+    onError = pIdx->onError;
+    if( onError==OE_None ){
+      sqlite3VdbeResolveLabel(v, addrUniqueOk);
+      continue;  /* pIdx is not a UNIQUE index */
+    }
+    if( overrideError!=OE_Default ){
+      onError = overrideError;
+    }else if( onError==OE_Default ){
+      onError = OE_Abort;
+    }
+
+    /* Figure out if the upsert clause applies to this index */
+    if( pUpsertClause ){
+      if( pUpsertClause->isDoUpdate==0 ){
+        onError = OE_Ignore;  /* DO NOTHING is the same as INSERT OR IGNORE */
+      }else{
+        onError = OE_Update;  /* DO UPDATE */
+      }
+    }
+
+    /* Collision detection may be omitted if all of the following are true:
+    **   (1) The conflict resolution algorithm is REPLACE
+    **   (2) The table is a WITHOUT ROWID table
+    **   (3) There are no secondary indexes on the table
+    **   (4) No delete triggers need to be fired if there is a conflict
+    **   (5) No FK constraint counters need to be updated if a conflict occurs.
+    **
+    ** This is not possible for ENABLE_PREUPDATE_HOOK builds, as the row
+    ** must be explicitly deleted in order to ensure any pre-update hook
+    ** is invoked.  */
+    assert( IsOrdinaryTable(pTab) );
+#ifndef SQLITE_ENABLE_PREUPDATE_HOOK
+    if( (ix==0 && pIdx->pNext==0)                   /* Condition 3 */
+     && pPk==pIdx                                   /* Condition 2 */
+     && onError==OE_Replace                         /* Condition 1 */
+     && ( 0==(db->flags&SQLITE_RecTriggers) ||      /* Condition 4 */
+          0==sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0))
+     && ( 0==(db->flags&SQLITE_ForeignKeys) ||      /* Condition 5 */
+         (0==pTab->u.tab.pFKey && 0==sqlite3FkReferences(pTab)))
+    ){
+      sqlite3VdbeResolveLabel(v, addrUniqueOk);
+      continue;
+    }
+#endif /* ifndef SQLITE_ENABLE_PREUPDATE_HOOK */
+
+    /* Check to see if the new index entry will be unique */
+    sqlite3VdbeVerifyAbortable(v, onError);
+    addrConflictCk =
+      sqlite3VdbeAddOp4Int(v, OP_NoConflict, iThisCur, addrUniqueOk,
+                           regIdx, pIdx->nKeyCol); VdbeCoverage(v);
+
+    /* Generate code to handle collisions */
+    regR = pIdx==pPk ? regIdx : sqlite3GetTempRange(pParse, nPkField);
+    if( isUpdate || onError==OE_Replace ){
+      if( HasRowid(pTab) ){
+        sqlite3VdbeAddOp2(v, OP_IdxRowid, iThisCur, regR);
+        /* Conflict only if the rowid of the existing index entry
+        ** is different from old-rowid */
+        if( isUpdate ){
+          sqlite3VdbeAddOp3(v, OP_Eq, regR, addrUniqueOk, regOldData);
+          sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+          VdbeCoverage(v);
+        }
+      }else{
+        int x;
+        /* Extract the PRIMARY KEY from the end of the index entry and
+        ** store it in registers regR..regR+nPk-1 */
+        if( pIdx!=pPk ){
+          for(i=0; i<pPk->nKeyCol; i++){
+            assert( pPk->aiColumn[i]>=0 );
+            x = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[i]);
+            sqlite3VdbeAddOp3(v, OP_Column, iThisCur, x, regR+i);
+            VdbeComment((v, "%s.%s", pTab->zName,
+                         pTab->aCol[pPk->aiColumn[i]].zCnName));
+          }
+        }
+        if( isUpdate ){
+          /* If currently processing the PRIMARY KEY of a WITHOUT ROWID
+          ** table, only conflict if the new PRIMARY KEY values are actually
+          ** different from the old.  See TH3 withoutrowid04.test.
+          **
+          ** For a UNIQUE index, only conflict if the PRIMARY KEY values
+          ** of the matched index row are different from the original PRIMARY
+          ** KEY values of this row before the update.  */
+          int addrJump = sqlite3VdbeCurrentAddr(v)+pPk->nKeyCol;
+          int op = OP_Ne;
+          int regCmp = (IsPrimaryKeyIndex(pIdx) ? regIdx : regR);
+
+          for(i=0; i<pPk->nKeyCol; i++){
+            char *p4 = (char*)sqlite3LocateCollSeq(pParse, pPk->azColl[i]);
+            x = pPk->aiColumn[i];
+            assert( x>=0 );
+            if( i==(pPk->nKeyCol-1) ){
+              addrJump = addrUniqueOk;
+              op = OP_Eq;
+            }
+            x = sqlite3TableColumnToStorage(pTab, x);
+            sqlite3VdbeAddOp4(v, op,
+                regOldData+1+x, addrJump, regCmp+i, p4, P4_COLLSEQ
+            );
+            sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+            VdbeCoverageIf(v, op==OP_Eq);
+            VdbeCoverageIf(v, op==OP_Ne);
+          }
+        }
+      }
+    }
+
+    /* Generate code that executes if the new index entry is not unique */
+    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
+        || onError==OE_Ignore || onError==OE_Replace || onError==OE_Update );
+    switch( onError ){
+      case OE_Rollback:
+      case OE_Abort:
+      case OE_Fail: {
+        testcase( onError==OE_Rollback );
+        testcase( onError==OE_Abort );
+        testcase( onError==OE_Fail );
+        sqlite3UniqueConstraint(pParse, onError, pIdx);
+        break;
+      }
+#ifndef SQLITE_OMIT_UPSERT
+      case OE_Update: {
+        sqlite3UpsertDoUpdate(pParse, pUpsert, pTab, pIdx, iIdxCur+ix);
+        /* no break */ deliberate_fall_through
+      }
+#endif
+      case OE_Ignore: {
+        testcase( onError==OE_Ignore );
+        sqlite3VdbeGoto(v, ignoreDest);
+        break;
+      }
+      default: {
+        int nConflictCk;   /* Number of opcodes in conflict check logic */
+
+        assert( onError==OE_Replace );
+        nConflictCk = sqlite3VdbeCurrentAddr(v) - addrConflictCk;
+        assert( nConflictCk>0 || db->mallocFailed );
+        testcase( nConflictCk<=0 );
+        testcase( nConflictCk>1 );
+        if( regTrigCnt ){
+          sqlite3MultiWrite(pParse);
+          nReplaceTrig++;
+        }
+        if( pTrigger && isUpdate ){
+          sqlite3VdbeAddOp1(v, OP_CursorLock, iDataCur);
+        }
+        sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
+            regR, nPkField, 0, OE_Replace,
+            (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
+        if( pTrigger && isUpdate ){
+          sqlite3VdbeAddOp1(v, OP_CursorUnlock, iDataCur);
+        }
+        if( regTrigCnt ){
+          int addrBypass;  /* Jump destination to bypass recheck logic */
+
+          sqlite3VdbeAddOp2(v, OP_AddImm, regTrigCnt, 1); /* incr trigger cnt */
+          addrBypass = sqlite3VdbeAddOp0(v, OP_Goto);  /* Bypass recheck */
+          VdbeComment((v, "bypass recheck"));
+
+          /* Here we insert code that will be invoked after all constraint
+          ** checks have run, if and only if one or more replace triggers
+          ** fired. */
+          sqlite3VdbeResolveLabel(v, lblRecheckOk);
+          lblRecheckOk = sqlite3VdbeMakeLabel(pParse);
+          if( pIdx->pPartIdxWhere ){
+            /* Bypass the recheck if this partial index is not defined
+            ** for the current row */
+            sqlite3VdbeAddOp2(v, OP_IsNull, regIdx-1, lblRecheckOk);
+            VdbeCoverage(v);
+          }
+          /* Copy the constraint check code from above, except change
+          ** the constraint-ok jump destination to be the address of
+          ** the next retest block */
+          while( nConflictCk>0 ){
+            VdbeOp x;    /* Conflict check opcode to copy */
+            /* The sqlite3VdbeAddOp4() call might reallocate the opcode array.
+            ** Hence, make a complete copy of the opcode, rather than using
+            ** a pointer to the opcode. */
+            x = *sqlite3VdbeGetOp(v, addrConflictCk);
+            if( x.opcode!=OP_IdxRowid ){
+              int p2;      /* New P2 value for copied conflict check opcode */
+              const char *zP4;
+              if( sqlite3OpcodeProperty[x.opcode]&OPFLG_JUMP ){
+                p2 = lblRecheckOk;
+              }else{
+                p2 = x.p2;
+              }
+              zP4 = x.p4type==P4_INT32 ? SQLITE_INT_TO_PTR(x.p4.i) : x.p4.z;
+              sqlite3VdbeAddOp4(v, x.opcode, x.p1, p2, x.p3, zP4, x.p4type);
+              sqlite3VdbeChangeP5(v, x.p5);
+              VdbeCoverageIf(v, p2!=x.p2);
+            }
+            nConflictCk--;
+            addrConflictCk++;
+          }
+          /* If the retest fails, issue an abort */
+          sqlite3UniqueConstraint(pParse, OE_Abort, pIdx);
+
+          sqlite3VdbeJumpHere(v, addrBypass); /* Terminate the recheck bypass */
+        }
+        seenReplace = 1;
+        break;
+      }
+    }
+    sqlite3VdbeResolveLabel(v, addrUniqueOk);
+    if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);
+    if( pUpsertClause
+     && upsertIpkReturn
+     && sqlite3UpsertNextIsIPK(pUpsertClause)
+    ){
+      sqlite3VdbeGoto(v, upsertIpkDelay+1);
+      sqlite3VdbeJumpHere(v, upsertIpkReturn);
+      upsertIpkReturn = 0;
+    }
+  }
+
+  /* If the IPK constraint is a REPLACE, run it last */
+  if( ipkTop ){
+    sqlite3VdbeGoto(v, ipkTop);
+    VdbeComment((v, "Do IPK REPLACE"));
+    assert( ipkBottom>0 );
+    sqlite3VdbeJumpHere(v, ipkBottom);
+  }
+
+  /* Recheck all uniqueness constraints after replace triggers have run */
+  testcase( regTrigCnt!=0 && nReplaceTrig==0 );
+  assert( regTrigCnt!=0 || nReplaceTrig==0 );
+  if( nReplaceTrig ){
+    sqlite3VdbeAddOp2(v, OP_IfNot, regTrigCnt, lblRecheckOk);VdbeCoverage(v);
+    if( !pPk ){
+      if( isUpdate ){
+        sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRecheck, regOldData);
+        sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
+        VdbeCoverage(v);
+      }
+      sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRecheck, regNewData);
+      VdbeCoverage(v);
+      sqlite3RowidConstraint(pParse, OE_Abort, pTab);
+    }else{
+      sqlite3VdbeGoto(v, addrRecheck);
+    }
+    sqlite3VdbeResolveLabel(v, lblRecheckOk);
+  }
+
+  /* Generate the table record */
+  if( HasRowid(pTab) ){
+    int regRec = aRegIdx[ix];
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regNewData+1, pTab->nNVCol, regRec);
+    sqlite3SetMakeRecordP5(v, pTab);
+    if( !bAffinityDone ){
+      sqlite3TableAffinity(v, pTab, 0);
+    }
+  }
+
+  *pbMayReplace = seenReplace;
+  VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
+}
+
+#ifdef SQLITE_ENABLE_NULL_TRIM
+/*
+** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
+** to be the number of columns in table pTab that must not be NULL-trimmed.
+**
+** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
+*/
+SQLITE_PRIVATE void sqlite3SetMakeRecordP5(Vdbe *v, Table *pTab){
+  u16 i;
+
+  /* Records with omitted columns are only allowed for schema format
+  ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
+  if( pTab->pSchema->file_format<2 ) return;
+
+  for(i=pTab->nCol-1; i>0; i--){
+    if( pTab->aCol[i].iDflt!=0 ) break;
+    if( pTab->aCol[i].colFlags & COLFLAG_PRIMKEY ) break;
+  }
+  sqlite3VdbeChangeP5(v, i+1);
+}
+#endif
+
+/*
+** Table pTab is a WITHOUT ROWID table that is being written to. The cursor
+** number is iCur, and register regData contains the new record for the
+** PK index. This function adds code to invoke the pre-update hook,
+** if one is registered.
+*/
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+static void codeWithoutRowidPreupdate(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being updated */
+  int iCur,                       /* Cursor number for table */
+  int regData                     /* Data containing new record */
+){
+  Vdbe *v = pParse->pVdbe;
+  int r = sqlite3GetTempReg(pParse);
+  assert( !HasRowid(pTab) );
+  assert( 0==(pParse->db->mDbFlags & DBFLAG_Vacuum) || CORRUPT_DB );
+  sqlite3VdbeAddOp2(v, OP_Integer, 0, r);
+  sqlite3VdbeAddOp4(v, OP_Insert, iCur, regData, r, (char*)pTab, P4_TABLE);
+  sqlite3VdbeChangeP5(v, OPFLAG_ISNOOP);
+  sqlite3ReleaseTempReg(pParse, r);
+}
+#else
+# define codeWithoutRowidPreupdate(a,b,c,d)
+#endif
+
+/*
+** This routine generates code to finish the INSERT or UPDATE operation
+** that was started by a prior call to sqlite3GenerateConstraintChecks.
+** A consecutive range of registers starting at regNewData contains the
+** rowid and the content to be inserted.
+**
+** The arguments to this routine should be the same as the first six
+** arguments to sqlite3GenerateConstraintChecks.
+*/
+SQLITE_PRIVATE void sqlite3CompleteInsertion(
+  Parse *pParse,      /* The parser context */
+  Table *pTab,        /* the table into which we are inserting */
+  int iDataCur,       /* Cursor of the canonical data source */
+  int iIdxCur,        /* First index cursor */
+  int regNewData,     /* Range of content */
+  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
+  int update_flags,   /* True for UPDATE, False for INSERT */
+  int appendBias,     /* True if this is likely to be an append */
+  int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
+){
+  Vdbe *v;            /* Prepared statements under construction */
+  Index *pIdx;        /* An index being inserted or updated */
+  u8 pik_flags;       /* flag values passed to the btree insert */
+  int i;              /* Loop counter */
+
+  assert( update_flags==0
+       || update_flags==OPFLAG_ISUPDATE
+       || update_flags==(OPFLAG_ISUPDATE|OPFLAG_SAVEPOSITION)
+  );
+
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  assert( !IsView(pTab) );  /* This table is not a VIEW */
+  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+    /* All REPLACE indexes are at the end of the list */
+    assert( pIdx->onError!=OE_Replace
+         || pIdx->pNext==0
+         || pIdx->pNext->onError==OE_Replace );
+    if( aRegIdx[i]==0 ) continue;
+    if( pIdx->pPartIdxWhere ){
+      sqlite3VdbeAddOp2(v, OP_IsNull, aRegIdx[i], sqlite3VdbeCurrentAddr(v)+2);
+      VdbeCoverage(v);
+    }
+    pik_flags = (useSeekResult ? OPFLAG_USESEEKRESULT : 0);
+    if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
+      pik_flags |= OPFLAG_NCHANGE;
+      pik_flags |= (update_flags & OPFLAG_SAVEPOSITION);
+      if( update_flags==0 ){
+        codeWithoutRowidPreupdate(pParse, pTab, iIdxCur+i, aRegIdx[i]);
+      }
+    }
+    sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iIdxCur+i, aRegIdx[i],
+                         aRegIdx[i]+1,
+                         pIdx->uniqNotNull ? pIdx->nKeyCol: pIdx->nColumn);
+    sqlite3VdbeChangeP5(v, pik_flags);
+  }
+  if( !HasRowid(pTab) ) return;
+  if( pParse->nested ){
+    pik_flags = 0;
+  }else{
+    pik_flags = OPFLAG_NCHANGE;
+    pik_flags |= (update_flags?update_flags:OPFLAG_LASTROWID);
+  }
+  if( appendBias ){
+    pik_flags |= OPFLAG_APPEND;
+  }
+  if( useSeekResult ){
+    pik_flags |= OPFLAG_USESEEKRESULT;
+  }
+  sqlite3VdbeAddOp3(v, OP_Insert, iDataCur, aRegIdx[i], regNewData);
+  if( !pParse->nested ){
+    sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+  }
+  sqlite3VdbeChangeP5(v, pik_flags);
+}
+
+/*
+** Allocate cursors for the pTab table and all its indices and generate
+** code to open and initialized those cursors.
+**
+** The cursor for the object that contains the complete data (normally
+** the table itself, but the PRIMARY KEY index in the case of a WITHOUT
+** ROWID table) is returned in *piDataCur.  The first index cursor is
+** returned in *piIdxCur.  The number of indices is returned.
+**
+** Use iBase as the first cursor (either the *piDataCur for rowid tables
+** or the first index for WITHOUT ROWID tables) if it is non-negative.
+** If iBase is negative, then allocate the next available cursor.
+**
+** For a rowid table, *piDataCur will be exactly one less than *piIdxCur.
+** For a WITHOUT ROWID table, *piDataCur will be somewhere in the range
+** of *piIdxCurs, depending on where the PRIMARY KEY index appears on the
+** pTab->pIndex list.
+**
+** If pTab is a virtual table, then this routine is a no-op and the
+** *piDataCur and *piIdxCur values are left uninitialized.
+*/
+SQLITE_PRIVATE int sqlite3OpenTableAndIndices(
+  Parse *pParse,   /* Parsing context */
+  Table *pTab,     /* Table to be opened */
+  int op,          /* OP_OpenRead or OP_OpenWrite */
+  u8 p5,           /* P5 value for OP_Open* opcodes (except on WITHOUT ROWID) */
+  int iBase,       /* Use this for the table cursor, if there is one */
+  u8 *aToOpen,     /* If not NULL: boolean for each table and index */
+  int *piDataCur,  /* Write the database source cursor number here */
+  int *piIdxCur    /* Write the first index cursor number here */
+){
+  int i;
+  int iDb;
+  int iDataCur;
+  Index *pIdx;
+  Vdbe *v;
+
+  assert( op==OP_OpenRead || op==OP_OpenWrite );
+  assert( op==OP_OpenWrite || p5==0 );
+  assert( piDataCur!=0 );
+  assert( piIdxCur!=0 );
+  if( IsVirtual(pTab) ){
+    /* This routine is a no-op for virtual tables. Leave the output
+    ** variables *piDataCur and *piIdxCur set to illegal cursor numbers
+    ** for improved error detection. */
+    *piDataCur = *piIdxCur = -999;
+    return 0;
+  }
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  if( iBase<0 ) iBase = pParse->nTab;
+  iDataCur = iBase++;
+  *piDataCur = iDataCur;
+  if( HasRowid(pTab) && (aToOpen==0 || aToOpen[0]) ){
+    sqlite3OpenTable(pParse, iDataCur, iDb, pTab, op);
+  }else if( pParse->db->noSharedCache==0 ){
+    sqlite3TableLock(pParse, iDb, pTab->tnum, op==OP_OpenWrite, pTab->zName);
+  }
+  *piIdxCur = iBase;
+  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+    int iIdxCur = iBase++;
+    assert( pIdx->pSchema==pTab->pSchema );
+    if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
+      *piDataCur = iIdxCur;
+      p5 = 0;
+    }
+    if( aToOpen==0 || aToOpen[i+1] ){
+      sqlite3VdbeAddOp3(v, op, iIdxCur, pIdx->tnum, iDb);
+      sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+      sqlite3VdbeChangeP5(v, p5);
+      VdbeComment((v, "%s", pIdx->zName));
+    }
+  }
+  if( iBase>pParse->nTab ) pParse->nTab = iBase;
+  return i;
+}
+
+
+#ifdef SQLITE_TEST
+/*
+** The following global variable is incremented whenever the
+** transfer optimization is used.  This is used for testing
+** purposes only - to make sure the transfer optimization really
+** is happening when it is supposed to.
+*/
+SQLITE_API int sqlite3_xferopt_count;
+#endif /* SQLITE_TEST */
+
+
+#ifndef SQLITE_OMIT_XFER_OPT
+/*
+** Check to see if index pSrc is compatible as a source of data
+** for index pDest in an insert transfer optimization.  The rules
+** for a compatible index:
+**
+**    *   The index is over the same set of columns
+**    *   The same DESC and ASC markings occurs on all columns
+**    *   The same onError processing (OE_Abort, OE_Ignore, etc)
+**    *   The same collating sequence on each column
+**    *   The index has the exact same WHERE clause
+*/
+static int xferCompatibleIndex(Index *pDest, Index *pSrc){
+  int i;
+  assert( pDest && pSrc );
+  assert( pDest->pTable!=pSrc->pTable );
+  if( pDest->nKeyCol!=pSrc->nKeyCol || pDest->nColumn!=pSrc->nColumn ){
+    return 0;   /* Different number of columns */
+  }
+  if( pDest->onError!=pSrc->onError ){
+    return 0;   /* Different conflict resolution strategies */
+  }
+  for(i=0; i<pSrc->nKeyCol; i++){
+    if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
+      return 0;   /* Different columns indexed */
+    }
+    if( pSrc->aiColumn[i]==XN_EXPR ){
+      assert( pSrc->aColExpr!=0 && pDest->aColExpr!=0 );
+      if( sqlite3ExprCompare(0, pSrc->aColExpr->a[i].pExpr,
+                             pDest->aColExpr->a[i].pExpr, -1)!=0 ){
+        return 0;   /* Different expressions in the index */
+      }
+    }
+    if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
+      return 0;   /* Different sort orders */
+    }
+    if( sqlite3_stricmp(pSrc->azColl[i],pDest->azColl[i])!=0 ){
+      return 0;   /* Different collating sequences */
+    }
+  }
+  if( sqlite3ExprCompare(0, pSrc->pPartIdxWhere, pDest->pPartIdxWhere, -1) ){
+    return 0;     /* Different WHERE clauses */
+  }
+
+  /* If no test above fails then the indices must be compatible */
+  return 1;
+}
+
+/*
+** Attempt the transfer optimization on INSERTs of the form
+**
+**     INSERT INTO tab1 SELECT * FROM tab2;
+**
+** The xfer optimization transfers raw records from tab2 over to tab1.
+** Columns are not decoded and reassembled, which greatly improves
+** performance.  Raw index records are transferred in the same way.
+**
+** The xfer optimization is only attempted if tab1 and tab2 are compatible.
+** There are lots of rules for determining compatibility - see comments
+** embedded in the code for details.
+**
+** This routine returns TRUE if the optimization is guaranteed to be used.
+** Sometimes the xfer optimization will only work if the destination table
+** is empty - a factor that can only be determined at run-time.  In that
+** case, this routine generates code for the xfer optimization but also
+** does a test to see if the destination table is empty and jumps over the
+** xfer optimization code if the test fails.  In that case, this routine
+** returns FALSE so that the caller will know to go ahead and generate
+** an unoptimized transfer.  This routine also returns FALSE if there
+** is no chance that the xfer optimization can be applied.
+**
+** This optimization is particularly useful at making VACUUM run faster.
+*/
+static int xferOptimization(
+  Parse *pParse,        /* Parser context */
+  Table *pDest,         /* The table we are inserting into */
+  Select *pSelect,      /* A SELECT statement to use as the data source */
+  int onError,          /* How to handle constraint errors */
+  int iDbDest           /* The database of pDest */
+){
+  sqlite3 *db = pParse->db;
+  ExprList *pEList;                /* The result set of the SELECT */
+  Table *pSrc;                     /* The table in the FROM clause of SELECT */
+  Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
+  SrcItem *pItem;                  /* An element of pSelect->pSrc */
+  int i;                           /* Loop counter */
+  int iDbSrc;                      /* The database of pSrc */
+  int iSrc, iDest;                 /* Cursors from source and destination */
+  int addr1, addr2;                /* Loop addresses */
+  int emptyDestTest = 0;           /* Address of test for empty pDest */
+  int emptySrcTest = 0;            /* Address of test for empty pSrc */
+  Vdbe *v;                         /* The VDBE we are building */
+  int regAutoinc;                  /* Memory register used by AUTOINC */
+  int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */
+  int regData, regRowid;           /* Registers holding data and rowid */
+
+  assert( pSelect!=0 );
+  if( pParse->pWith || pSelect->pWith ){
+    /* Do not attempt to process this query if there are an WITH clauses
+    ** attached to it. Proceeding may generate a false "no such table: xxx"
+    ** error if pSelect reads from a CTE named "xxx".  */
+    return 0;
+  }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( IsVirtual(pDest) ){
+    return 0;   /* tab1 must not be a virtual table */
+  }
+#endif
+  if( onError==OE_Default ){
+    if( pDest->iPKey>=0 ) onError = pDest->keyConf;
+    if( onError==OE_Default ) onError = OE_Abort;
+  }
+  assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
+  if( pSelect->pSrc->nSrc!=1 ){
+    return 0;   /* FROM clause must have exactly one term */
+  }
+  if( pSelect->pSrc->a[0].fg.isSubquery ){
+    return 0;   /* FROM clause cannot contain a subquery */
+  }
+  if( pSelect->pWhere ){
+    return 0;   /* SELECT may not have a WHERE clause */
+  }
+  if( pSelect->pOrderBy ){
+    return 0;   /* SELECT may not have an ORDER BY clause */
+  }
+  /* Do not need to test for a HAVING clause.  If HAVING is present but
+  ** there is no ORDER BY, we will get an error. */
+  if( pSelect->pGroupBy ){
+    return 0;   /* SELECT may not have a GROUP BY clause */
+  }
+  if( pSelect->pLimit ){
+    return 0;   /* SELECT may not have a LIMIT clause */
+  }
+  if( pSelect->pPrior ){
+    return 0;   /* SELECT may not be a compound query */
+  }
+  if( pSelect->selFlags & SF_Distinct ){
+    return 0;   /* SELECT may not be DISTINCT */
+  }
+  pEList = pSelect->pEList;
+  assert( pEList!=0 );
+  if( pEList->nExpr!=1 ){
+    return 0;   /* The result set must have exactly one column */
+  }
+  assert( pEList->a[0].pExpr );
+  if( pEList->a[0].pExpr->op!=TK_ASTERISK ){
+    return 0;   /* The result set must be the special operator "*" */
+  }
+
+  /* At this point we have established that the statement is of the
+  ** correct syntactic form to participate in this optimization.  Now
+  ** we have to check the semantics.
+  */
+  pItem = pSelect->pSrc->a;
+  pSrc = sqlite3LocateTableItem(pParse, 0, pItem);
+  if( pSrc==0 ){
+    return 0;   /* FROM clause does not contain a real table */
+  }
+  if( pSrc->tnum==pDest->tnum && pSrc->pSchema==pDest->pSchema ){
+    testcase( pSrc!=pDest ); /* Possible due to bad sqlite_schema.rootpage */
+    return 0;   /* tab1 and tab2 may not be the same table */
+  }
+  if( HasRowid(pDest)!=HasRowid(pSrc) ){
+    return 0;   /* source and destination must both be WITHOUT ROWID or not */
+  }
+  if( !IsOrdinaryTable(pSrc) ){
+    return 0;   /* tab2 may not be a view or virtual table */
+  }
+  if( pDest->nCol!=pSrc->nCol ){
+    return 0;   /* Number of columns must be the same in tab1 and tab2 */
+  }
+  if( pDest->iPKey!=pSrc->iPKey ){
+    return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
+  }
+  if( (pDest->tabFlags & TF_Strict)!=0 && (pSrc->tabFlags & TF_Strict)==0 ){
+    return 0;   /* Cannot feed from a non-strict into a strict table */
+  }
+  for(i=0; i<pDest->nCol; i++){
+    Column *pDestCol = &pDest->aCol[i];
+    Column *pSrcCol = &pSrc->aCol[i];
+#ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
+    if( (db->mDbFlags & DBFLAG_Vacuum)==0
+     && (pDestCol->colFlags | pSrcCol->colFlags) & COLFLAG_HIDDEN
+    ){
+      return 0;    /* Neither table may have __hidden__ columns */
+    }
+#endif
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    /* Even if tables t1 and t2 have identical schemas, if they contain
+    ** generated columns, then this statement is semantically incorrect:
+    **
+    **     INSERT INTO t2 SELECT * FROM t1;
+    **
+    ** The reason is that generated column values are returned by the
+    ** the SELECT statement on the right but the INSERT statement on the
+    ** left wants them to be omitted.
+    **
+    ** Nevertheless, this is a useful notational shorthand to tell SQLite
+    ** to do a bulk transfer all of the content from t1 over to t2.
+    **
+    ** We could, in theory, disable this (except for internal use by the
+    ** VACUUM command where it is actually needed).  But why do that?  It
+    ** seems harmless enough, and provides a useful service.
+    */
+    if( (pDestCol->colFlags & COLFLAG_GENERATED) !=
+        (pSrcCol->colFlags & COLFLAG_GENERATED) ){
+      return 0;    /* Both columns have the same generated-column type */
+    }
+    /* But the transfer is only allowed if both the source and destination
+    ** tables have the exact same expressions for generated columns.
+    ** This requirement could be relaxed for VIRTUAL columns, I suppose.
+    */
+    if( (pDestCol->colFlags & COLFLAG_GENERATED)!=0 ){
+      if( sqlite3ExprCompare(0,
+             sqlite3ColumnExpr(pSrc, pSrcCol),
+             sqlite3ColumnExpr(pDest, pDestCol), -1)!=0 ){
+        testcase( pDestCol->colFlags & COLFLAG_VIRTUAL );
+        testcase( pDestCol->colFlags & COLFLAG_STORED );
+        return 0;  /* Different generator expressions */
+      }
+    }
+#endif
+    if( pDestCol->affinity!=pSrcCol->affinity ){
+      return 0;    /* Affinity must be the same on all columns */
+    }
+    if( sqlite3_stricmp(sqlite3ColumnColl(pDestCol),
+                        sqlite3ColumnColl(pSrcCol))!=0 ){
+      return 0;    /* Collating sequence must be the same on all columns */
+    }
+    if( pDestCol->notNull && !pSrcCol->notNull ){
+      return 0;    /* tab2 must be NOT NULL if tab1 is */
+    }
+    /* Default values for second and subsequent columns need to match. */
+    if( (pDestCol->colFlags & COLFLAG_GENERATED)==0 && i>0 ){
+      Expr *pDestExpr = sqlite3ColumnExpr(pDest, pDestCol);
+      Expr *pSrcExpr = sqlite3ColumnExpr(pSrc, pSrcCol);
+      assert( pDestExpr==0 || pDestExpr->op==TK_SPAN );
+      assert( pDestExpr==0 || !ExprHasProperty(pDestExpr, EP_IntValue) );
+      assert( pSrcExpr==0 || pSrcExpr->op==TK_SPAN );
+      assert( pSrcExpr==0 || !ExprHasProperty(pSrcExpr, EP_IntValue) );
+      if( (pDestExpr==0)!=(pSrcExpr==0)
+       || (pDestExpr!=0 && strcmp(pDestExpr->u.zToken,
+                                       pSrcExpr->u.zToken)!=0)
+      ){
+        return 0;    /* Default values must be the same for all columns */
+      }
+    }
+  }
+  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
+    if( IsUniqueIndex(pDestIdx) ){
+      destHasUniqueIdx = 1;
+    }
+    for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
+      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
+    }
+    if( pSrcIdx==0 ){
+      return 0;    /* pDestIdx has no corresponding index in pSrc */
+    }
+    if( pSrcIdx->tnum==pDestIdx->tnum && pSrc->pSchema==pDest->pSchema
+         && sqlite3FaultSim(411)==SQLITE_OK ){
+      /* The sqlite3FaultSim() call allows this corruption test to be
+      ** bypassed during testing, in order to exercise other corruption tests
+      ** further downstream. */
+      return 0;   /* Corrupt schema - two indexes on the same btree */
+    }
+  }
+#ifndef SQLITE_OMIT_CHECK
+  if( pDest->pCheck
+   && (db->mDbFlags & DBFLAG_Vacuum)==0
+   && sqlite3ExprListCompare(pSrc->pCheck,pDest->pCheck,-1)
+  ){
+    return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
+  }
+#endif
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  /* Disallow the transfer optimization if the destination table contains
+  ** any foreign key constraints.  This is more restrictive than necessary.
+  ** But the main beneficiary of the transfer optimization is the VACUUM
+  ** command, and the VACUUM command disables foreign key constraints.  So
+  ** the extra complication to make this rule less restrictive is probably
+  ** not worth the effort.  Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
+  */
+  assert( IsOrdinaryTable(pDest) );
+  if( (db->flags & SQLITE_ForeignKeys)!=0 && pDest->u.tab.pFKey!=0 ){
+    return 0;
+  }
+#endif
+  if( (db->flags & SQLITE_CountRows)!=0 ){
+    return 0;  /* xfer opt does not play well with PRAGMA count_changes */
+  }
+
+  /* If we get this far, it means that the xfer optimization is at
+  ** least a possibility, though it might only work if the destination
+  ** table (tab1) is initially empty.
+  */
+#ifdef SQLITE_TEST
+  sqlite3_xferopt_count++;
+#endif
+  iDbSrc = sqlite3SchemaToIndex(db, pSrc->pSchema);
+  v = sqlite3GetVdbe(pParse);
+  sqlite3CodeVerifySchema(pParse, iDbSrc);
+  iSrc = pParse->nTab++;
+  iDest = pParse->nTab++;
+  regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
+  regData = sqlite3GetTempReg(pParse);
+  sqlite3VdbeAddOp2(v, OP_Null, 0, regData);
+  regRowid = sqlite3GetTempReg(pParse);
+  sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
+  assert( HasRowid(pDest) || destHasUniqueIdx );
+  if( (db->mDbFlags & DBFLAG_Vacuum)==0 && (
+      (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
+   || destHasUniqueIdx                              /* (2) */
+   || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
+  )){
+    /* In some circumstances, we are able to run the xfer optimization
+    ** only if the destination table is initially empty. Unless the
+    ** DBFLAG_Vacuum flag is set, this block generates code to make
+    ** that determination. If DBFLAG_Vacuum is set, then the destination
+    ** table is always empty.
+    **
+    ** Conditions under which the destination must be empty:
+    **
+    ** (1) There is no INTEGER PRIMARY KEY but there are indices.
+    **     (If the destination is not initially empty, the rowid fields
+    **     of index entries might need to change.)
+    **
+    ** (2) The destination has a unique index.  (The xfer optimization
+    **     is unable to test uniqueness.)
+    **
+    ** (3) onError is something other than OE_Abort and OE_Rollback.
+    */
+    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0); VdbeCoverage(v);
+    emptyDestTest = sqlite3VdbeAddOp0(v, OP_Goto);
+    sqlite3VdbeJumpHere(v, addr1);
+  }
+  if( HasRowid(pSrc) ){
+    u8 insFlags;
+    sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
+    emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
+    if( pDest->iPKey>=0 ){
+      addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
+      if( (db->mDbFlags & DBFLAG_Vacuum)==0 ){
+        sqlite3VdbeVerifyAbortable(v, onError);
+        addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
+        VdbeCoverage(v);
+        sqlite3RowidConstraint(pParse, onError, pDest);
+        sqlite3VdbeJumpHere(v, addr2);
+      }
+      autoIncStep(pParse, regAutoinc, regRowid);
+    }else if( pDest->pIndex==0 && !(db->mDbFlags & DBFLAG_VacuumInto) ){
+      addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
+    }else{
+      addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
+      assert( (pDest->tabFlags & TF_Autoincrement)==0 );
+    }
+
+    if( db->mDbFlags & DBFLAG_Vacuum ){
+      sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
+      insFlags = OPFLAG_APPEND|OPFLAG_USESEEKRESULT|OPFLAG_PREFORMAT;
+    }else{
+      insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND|OPFLAG_PREFORMAT;
+    }
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    if( (db->mDbFlags & DBFLAG_Vacuum)==0 ){
+      sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
+      insFlags &= ~OPFLAG_PREFORMAT;
+    }else
+#endif
+    {
+      sqlite3VdbeAddOp3(v, OP_RowCell, iDest, iSrc, regRowid);
+    }
+    sqlite3VdbeAddOp3(v, OP_Insert, iDest, regData, regRowid);
+    if( (db->mDbFlags & DBFLAG_Vacuum)==0 ){
+      sqlite3VdbeChangeP4(v, -1, (char*)pDest, P4_TABLE);
+    }
+    sqlite3VdbeChangeP5(v, insFlags);
+
+    sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1); VdbeCoverage(v);
+    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
+    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
+  }else{
+    sqlite3TableLock(pParse, iDbDest, pDest->tnum, 1, pDest->zName);
+    sqlite3TableLock(pParse, iDbSrc, pSrc->tnum, 0, pSrc->zName);
+  }
+  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
+    u8 idxInsFlags = 0;
+    for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
+      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
+    }
+    assert( pSrcIdx );
+    sqlite3VdbeAddOp3(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc);
+    sqlite3VdbeSetP4KeyInfo(pParse, pSrcIdx);
+    VdbeComment((v, "%s", pSrcIdx->zName));
+    sqlite3VdbeAddOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest);
+    sqlite3VdbeSetP4KeyInfo(pParse, pDestIdx);
+    sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR);
+    VdbeComment((v, "%s", pDestIdx->zName));
+    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
+    if( db->mDbFlags & DBFLAG_Vacuum ){
+      /* This INSERT command is part of a VACUUM operation, which guarantees
+      ** that the destination table is empty. If all indexed columns use
+      ** collation sequence BINARY, then it can also be assumed that the
+      ** index will be populated by inserting keys in strictly sorted
+      ** order. In this case, instead of seeking within the b-tree as part
+      ** of every OP_IdxInsert opcode, an OP_SeekEnd is added before the
+      ** OP_IdxInsert to seek to the point within the b-tree where each key
+      ** should be inserted. This is faster.
+      **
+      ** If any of the indexed columns use a collation sequence other than
+      ** BINARY, this optimization is disabled. This is because the user
+      ** might change the definition of a collation sequence and then run
+      ** a VACUUM command. In that case keys may not be written in strictly
+      ** sorted order.  */
+      for(i=0; i<pSrcIdx->nColumn; i++){
+        const char *zColl = pSrcIdx->azColl[i];
+        if( sqlite3_stricmp(sqlite3StrBINARY, zColl) ) break;
+      }
+      if( i==pSrcIdx->nColumn ){
+        idxInsFlags = OPFLAG_USESEEKRESULT|OPFLAG_PREFORMAT;
+        sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
+        sqlite3VdbeAddOp2(v, OP_RowCell, iDest, iSrc);
+      }
+    }else if( !HasRowid(pSrc) && pDestIdx->idxType==SQLITE_IDXTYPE_PRIMARYKEY ){
+      idxInsFlags |= OPFLAG_NCHANGE;
+    }
+    if( idxInsFlags!=(OPFLAG_USESEEKRESULT|OPFLAG_PREFORMAT) ){
+      sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
+      if( (db->mDbFlags & DBFLAG_Vacuum)==0
+       && !HasRowid(pDest)
+       && IsPrimaryKeyIndex(pDestIdx)
+      ){
+        codeWithoutRowidPreupdate(pParse, pDest, iDest, regData);
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_IdxInsert, iDest, regData);
+    sqlite3VdbeChangeP5(v, idxInsFlags|OPFLAG_APPEND);
+    sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr1);
+    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
+    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
+  }
+  if( emptySrcTest ) sqlite3VdbeJumpHere(v, emptySrcTest);
+  sqlite3ReleaseTempReg(pParse, regRowid);
+  sqlite3ReleaseTempReg(pParse, regData);
+  if( emptyDestTest ){
+    sqlite3AutoincrementEnd(pParse);
+    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
+    sqlite3VdbeJumpHere(v, emptyDestTest);
+    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
+    return 0;
+  }else{
+    return 1;
+  }
+}
+#endif /* SQLITE_OMIT_XFER_OPT */
+
+/************** End of insert.c **********************************************/
+/************** Begin file legacy.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Main file for the SQLite library.  The routines in this file
+** implement the programmer interface to the library.  Routines in
+** other files are for internal use by SQLite and should not be
+** accessed by users of the library.
+*/
+
+/* #include "sqliteInt.h" */
+
+/*
+** Execute SQL code.  Return one of the SQLITE_ success/failure
+** codes.  Also write an error message into memory obtained from
+** malloc() and make *pzErrMsg point to that message.
+**
+** If the SQL is a query, then for each row in the query result
+** the xCallback() function is called.  pArg becomes the first
+** argument to xCallback().  If xCallback=NULL then no callback
+** is invoked, even for queries.
+*/
+SQLITE_API int sqlite3_exec(
+  sqlite3 *db,                /* The database on which the SQL executes */
+  const char *zSql,           /* The SQL to be executed */
+  sqlite3_callback xCallback, /* Invoke this callback routine */
+  void *pArg,                 /* First argument to xCallback() */
+  char **pzErrMsg             /* Write error messages here */
+){
+  int rc = SQLITE_OK;         /* Return code */
+  const char *zLeftover;      /* Tail of unprocessed SQL */
+  sqlite3_stmt *pStmt = 0;    /* The current SQL statement */
+  char **azCols = 0;          /* Names of result columns */
+  int callbackIsInit;         /* True if callback data is initialized */
+
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+  if( zSql==0 ) zSql = "";
+
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3Error(db, SQLITE_OK);
+  while( rc==SQLITE_OK && zSql[0] ){
+    int nCol = 0;
+    char **azVals = 0;
+
+    pStmt = 0;
+    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, &zLeftover);
+    assert( rc==SQLITE_OK || pStmt==0 );
+    if( rc!=SQLITE_OK ){
+      continue;
+    }
+    if( !pStmt ){
+      /* this happens for a comment or white-space */
+      zSql = zLeftover;
+      continue;
+    }
+    callbackIsInit = 0;
+
+    while( 1 ){
+      int i;
+      rc = sqlite3_step(pStmt);
+
+      /* Invoke the callback function if required */
+      if( xCallback && (SQLITE_ROW==rc ||
+          (SQLITE_DONE==rc && !callbackIsInit
+                           && db->flags&SQLITE_NullCallback)) ){
+        if( !callbackIsInit ){
+          nCol = sqlite3_column_count(pStmt);
+          azCols = sqlite3DbMallocRaw(db, (2*nCol+1)*sizeof(const char*));
+          if( azCols==0 ){
+            goto exec_out;
+          }
+          for(i=0; i<nCol; i++){
+            azCols[i] = (char *)sqlite3_column_name(pStmt, i);
+            /* sqlite3VdbeSetColName() installs column names as UTF8
+            ** strings so there is no way for sqlite3_column_name() to fail. */
+            assert( azCols[i]!=0 );
+          }
+          callbackIsInit = 1;
+        }
+        if( rc==SQLITE_ROW ){
+          azVals = &azCols[nCol];
+          for(i=0; i<nCol; i++){
+            azVals[i] = (char *)sqlite3_column_text(pStmt, i);
+            if( !azVals[i] && sqlite3_column_type(pStmt, i)!=SQLITE_NULL ){
+              sqlite3OomFault(db);
+              goto exec_out;
+            }
+          }
+          azVals[i] = 0;
+        }
+        if( xCallback(pArg, nCol, azVals, azCols) ){
+          /* EVIDENCE-OF: R-38229-40159 If the callback function to
+          ** sqlite3_exec() returns non-zero, then sqlite3_exec() will
+          ** return SQLITE_ABORT. */
+          rc = SQLITE_ABORT;
+          sqlite3VdbeFinalize((Vdbe *)pStmt);
+          pStmt = 0;
+          sqlite3Error(db, SQLITE_ABORT);
+          goto exec_out;
+        }
+      }
+
+      if( rc!=SQLITE_ROW ){
+        rc = sqlite3VdbeFinalize((Vdbe *)pStmt);
+        pStmt = 0;
+        zSql = zLeftover;
+        while( sqlite3Isspace(zSql[0]) ) zSql++;
+        break;
+      }
+    }
+
+    sqlite3DbFree(db, azCols);
+    azCols = 0;
+  }
+
+exec_out:
+  if( pStmt ) sqlite3VdbeFinalize((Vdbe *)pStmt);
+  sqlite3DbFree(db, azCols);
+
+  rc = sqlite3ApiExit(db, rc);
+  if( rc!=SQLITE_OK && pzErrMsg ){
+    *pzErrMsg = sqlite3DbStrDup(0, sqlite3_errmsg(db));
+    if( *pzErrMsg==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      sqlite3Error(db, SQLITE_NOMEM);
+    }
+  }else if( pzErrMsg ){
+    *pzErrMsg = 0;
+  }
+
+  assert( (rc&db->errMask)==rc );
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/************** End of legacy.c **********************************************/
+/************** Begin file loadext.c *****************************************/
+/*
+** 2006 June 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to dynamically load extensions into
+** the SQLite library.
+*/
+
+#ifndef SQLITE_CORE
+  #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */
+#endif
+/************** Include sqlite3ext.h in the middle of loadext.c **************/
+/************** Begin file sqlite3ext.h **************************************/
+/*
+** 2006 June 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the SQLite interface for use by
+** shared libraries that want to be imported as extensions into
+** an SQLite instance.  Shared libraries that intend to be loaded
+** as extensions by SQLite should #include this file instead of
+** sqlite3.h.
+*/
+#ifndef SQLITE3EXT_H
+#define SQLITE3EXT_H
+/* #include "sqlite3.h" */
+
+/*
+** The following structure holds pointers to all of the SQLite API
+** routines.
+**
+** WARNING:  In order to maintain backwards compatibility, add new
+** interfaces to the end of this structure only.  If you insert new
+** interfaces in the middle of this structure, then older different
+** versions of SQLite will not be able to load each other's shared
+** libraries!
+*/
+struct sqlite3_api_routines {
+  void * (*aggregate_context)(sqlite3_context*,int nBytes);
+  int  (*aggregate_count)(sqlite3_context*);
+  int  (*bind_blob)(sqlite3_stmt*,int,const void*,int n,void(*)(void*));
+  int  (*bind_double)(sqlite3_stmt*,int,double);
+  int  (*bind_int)(sqlite3_stmt*,int,int);
+  int  (*bind_int64)(sqlite3_stmt*,int,sqlite_int64);
+  int  (*bind_null)(sqlite3_stmt*,int);
+  int  (*bind_parameter_count)(sqlite3_stmt*);
+  int  (*bind_parameter_index)(sqlite3_stmt*,const char*zName);
+  const char * (*bind_parameter_name)(sqlite3_stmt*,int);
+  int  (*bind_text)(sqlite3_stmt*,int,const char*,int n,void(*)(void*));
+  int  (*bind_text16)(sqlite3_stmt*,int,const void*,int,void(*)(void*));
+  int  (*bind_value)(sqlite3_stmt*,int,const sqlite3_value*);
+  int  (*busy_handler)(sqlite3*,int(*)(void*,int),void*);
+  int  (*busy_timeout)(sqlite3*,int ms);
+  int  (*changes)(sqlite3*);
+  int  (*close)(sqlite3*);
+  int  (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                           int eTextRep,const char*));
+  int  (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                             int eTextRep,const void*));
+  const void * (*column_blob)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes16)(sqlite3_stmt*,int iCol);
+  int  (*column_count)(sqlite3_stmt*pStmt);
+  const char * (*column_database_name)(sqlite3_stmt*,int);
+  const void * (*column_database_name16)(sqlite3_stmt*,int);
+  const char * (*column_decltype)(sqlite3_stmt*,int i);
+  const void * (*column_decltype16)(sqlite3_stmt*,int);
+  double  (*column_double)(sqlite3_stmt*,int iCol);
+  int  (*column_int)(sqlite3_stmt*,int iCol);
+  sqlite_int64  (*column_int64)(sqlite3_stmt*,int iCol);
+  const char * (*column_name)(sqlite3_stmt*,int);
+  const void * (*column_name16)(sqlite3_stmt*,int);
+  const char * (*column_origin_name)(sqlite3_stmt*,int);
+  const void * (*column_origin_name16)(sqlite3_stmt*,int);
+  const char * (*column_table_name)(sqlite3_stmt*,int);
+  const void * (*column_table_name16)(sqlite3_stmt*,int);
+  const unsigned char * (*column_text)(sqlite3_stmt*,int iCol);
+  const void * (*column_text16)(sqlite3_stmt*,int iCol);
+  int  (*column_type)(sqlite3_stmt*,int iCol);
+  sqlite3_value* (*column_value)(sqlite3_stmt*,int iCol);
+  void * (*commit_hook)(sqlite3*,int(*)(void*),void*);
+  int  (*complete)(const char*sql);
+  int  (*complete16)(const void*sql);
+  int  (*create_collation)(sqlite3*,const char*,int,void*,
+                           int(*)(void*,int,const void*,int,const void*));
+  int  (*create_collation16)(sqlite3*,const void*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*));
+  int  (*create_function)(sqlite3*,const char*,int,int,void*,
+                          void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xFinal)(sqlite3_context*));
+  int  (*create_function16)(sqlite3*,const void*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*));
+  int (*create_module)(sqlite3*,const char*,const sqlite3_module*,void*);
+  int  (*data_count)(sqlite3_stmt*pStmt);
+  sqlite3 * (*db_handle)(sqlite3_stmt*);
+  int (*declare_vtab)(sqlite3*,const char*);
+  int  (*enable_shared_cache)(int);
+  int  (*errcode)(sqlite3*db);
+  const char * (*errmsg)(sqlite3*);
+  const void * (*errmsg16)(sqlite3*);
+  int  (*exec)(sqlite3*,const char*,sqlite3_callback,void*,char**);
+  int  (*expired)(sqlite3_stmt*);
+  int  (*finalize)(sqlite3_stmt*pStmt);
+  void  (*free)(void*);
+  void  (*free_table)(char**result);
+  int  (*get_autocommit)(sqlite3*);
+  void * (*get_auxdata)(sqlite3_context*,int);
+  int  (*get_table)(sqlite3*,const char*,char***,int*,int*,char**);
+  int  (*global_recover)(void);
+  void  (*interruptx)(sqlite3*);
+  sqlite_int64  (*last_insert_rowid)(sqlite3*);
+  const char * (*libversion)(void);
+  int  (*libversion_number)(void);
+  void *(*malloc)(int);
+  char * (*mprintf)(const char*,...);
+  int  (*open)(const char*,sqlite3**);
+  int  (*open16)(const void*,sqlite3**);
+  int  (*prepare)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int  (*prepare16)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  void * (*profile)(sqlite3*,void(*)(void*,const char*,sqlite_uint64),void*);
+  void  (*progress_handler)(sqlite3*,int,int(*)(void*),void*);
+  void *(*realloc)(void*,int);
+  int  (*reset)(sqlite3_stmt*pStmt);
+  void  (*result_blob)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_double)(sqlite3_context*,double);
+  void  (*result_error)(sqlite3_context*,const char*,int);
+  void  (*result_error16)(sqlite3_context*,const void*,int);
+  void  (*result_int)(sqlite3_context*,int);
+  void  (*result_int64)(sqlite3_context*,sqlite_int64);
+  void  (*result_null)(sqlite3_context*);
+  void  (*result_text)(sqlite3_context*,const char*,int,void(*)(void*));
+  void  (*result_text16)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16be)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16le)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_value)(sqlite3_context*,sqlite3_value*);
+  void * (*rollback_hook)(sqlite3*,void(*)(void*),void*);
+  int  (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,
+                         const char*,const char*),void*);
+  void  (*set_auxdata)(sqlite3_context*,int,void*,void (*)(void*));
+  char * (*xsnprintf)(int,char*,const char*,...);
+  int  (*step)(sqlite3_stmt*);
+  int  (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,
+                                char const**,char const**,int*,int*,int*);
+  void  (*thread_cleanup)(void);
+  int  (*total_changes)(sqlite3*);
+  void * (*trace)(sqlite3*,void(*xTrace)(void*,const char*),void*);
+  int  (*transfer_bindings)(sqlite3_stmt*,sqlite3_stmt*);
+  void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,
+                                         sqlite_int64),void*);
+  void * (*user_data)(sqlite3_context*);
+  const void * (*value_blob)(sqlite3_value*);
+  int  (*value_bytes)(sqlite3_value*);
+  int  (*value_bytes16)(sqlite3_value*);
+  double  (*value_double)(sqlite3_value*);
+  int  (*value_int)(sqlite3_value*);
+  sqlite_int64  (*value_int64)(sqlite3_value*);
+  int  (*value_numeric_type)(sqlite3_value*);
+  const unsigned char * (*value_text)(sqlite3_value*);
+  const void * (*value_text16)(sqlite3_value*);
+  const void * (*value_text16be)(sqlite3_value*);
+  const void * (*value_text16le)(sqlite3_value*);
+  int  (*value_type)(sqlite3_value*);
+  char *(*vmprintf)(const char*,va_list);
+  /* Added ??? */
+  int (*overload_function)(sqlite3*, const char *zFuncName, int nArg);
+  /* Added by 3.3.13 */
+  int (*prepare_v2)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int (*prepare16_v2)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  int (*clear_bindings)(sqlite3_stmt*);
+  /* Added by 3.4.1 */
+  int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,
+                          void (*xDestroy)(void *));
+  /* Added by 3.5.0 */
+  int (*bind_zeroblob)(sqlite3_stmt*,int,int);
+  int (*blob_bytes)(sqlite3_blob*);
+  int (*blob_close)(sqlite3_blob*);
+  int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,
+                   int,sqlite3_blob**);
+  int (*blob_read)(sqlite3_blob*,void*,int,int);
+  int (*blob_write)(sqlite3_blob*,const void*,int,int);
+  int (*create_collation_v2)(sqlite3*,const char*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*),
+                             void(*)(void*));
+  int (*file_control)(sqlite3*,const char*,int,void*);
+  sqlite3_int64 (*memory_highwater)(int);
+  sqlite3_int64 (*memory_used)(void);
+  sqlite3_mutex *(*mutex_alloc)(int);
+  void (*mutex_enter)(sqlite3_mutex*);
+  void (*mutex_free)(sqlite3_mutex*);
+  void (*mutex_leave)(sqlite3_mutex*);
+  int (*mutex_try)(sqlite3_mutex*);
+  int (*open_v2)(const char*,sqlite3**,int,const char*);
+  int (*release_memory)(int);
+  void (*result_error_nomem)(sqlite3_context*);
+  void (*result_error_toobig)(sqlite3_context*);
+  int (*sleep)(int);
+  void (*soft_heap_limit)(int);
+  sqlite3_vfs *(*vfs_find)(const char*);
+  int (*vfs_register)(sqlite3_vfs*,int);
+  int (*vfs_unregister)(sqlite3_vfs*);
+  int (*xthreadsafe)(void);
+  void (*result_zeroblob)(sqlite3_context*,int);
+  void (*result_error_code)(sqlite3_context*,int);
+  int (*test_control)(int, ...);
+  void (*randomness)(int,void*);
+  sqlite3 *(*context_db_handle)(sqlite3_context*);
+  int (*extended_result_codes)(sqlite3*,int);
+  int (*limit)(sqlite3*,int,int);
+  sqlite3_stmt *(*next_stmt)(sqlite3*,sqlite3_stmt*);
+  const char *(*sql)(sqlite3_stmt*);
+  int (*status)(int,int*,int*,int);
+  int (*backup_finish)(sqlite3_backup*);
+  sqlite3_backup *(*backup_init)(sqlite3*,const char*,sqlite3*,const char*);
+  int (*backup_pagecount)(sqlite3_backup*);
+  int (*backup_remaining)(sqlite3_backup*);
+  int (*backup_step)(sqlite3_backup*,int);
+  const char *(*compileoption_get)(int);
+  int (*compileoption_used)(const char*);
+  int (*create_function_v2)(sqlite3*,const char*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void(*xDestroy)(void*));
+  int (*db_config)(sqlite3*,int,...);
+  sqlite3_mutex *(*db_mutex)(sqlite3*);
+  int (*db_status)(sqlite3*,int,int*,int*,int);
+  int (*extended_errcode)(sqlite3*);
+  void (*log)(int,const char*,...);
+  sqlite3_int64 (*soft_heap_limit64)(sqlite3_int64);
+  const char *(*sourceid)(void);
+  int (*stmt_status)(sqlite3_stmt*,int,int);
+  int (*strnicmp)(const char*,const char*,int);
+  int (*unlock_notify)(sqlite3*,void(*)(void**,int),void*);
+  int (*wal_autocheckpoint)(sqlite3*,int);
+  int (*wal_checkpoint)(sqlite3*,const char*);
+  void *(*wal_hook)(sqlite3*,int(*)(void*,sqlite3*,const char*,int),void*);
+  int (*blob_reopen)(sqlite3_blob*,sqlite3_int64);
+  int (*vtab_config)(sqlite3*,int op,...);
+  int (*vtab_on_conflict)(sqlite3*);
+  /* Version 3.7.16 and later */
+  int (*close_v2)(sqlite3*);
+  const char *(*db_filename)(sqlite3*,const char*);
+  int (*db_readonly)(sqlite3*,const char*);
+  int (*db_release_memory)(sqlite3*);
+  const char *(*errstr)(int);
+  int (*stmt_busy)(sqlite3_stmt*);
+  int (*stmt_readonly)(sqlite3_stmt*);
+  int (*stricmp)(const char*,const char*);
+  int (*uri_boolean)(const char*,const char*,int);
+  sqlite3_int64 (*uri_int64)(const char*,const char*,sqlite3_int64);
+  const char *(*uri_parameter)(const char*,const char*);
+  char *(*xvsnprintf)(int,char*,const char*,va_list);
+  int (*wal_checkpoint_v2)(sqlite3*,const char*,int,int*,int*);
+  /* Version 3.8.7 and later */
+  int (*auto_extension)(void(*)(void));
+  int (*bind_blob64)(sqlite3_stmt*,int,const void*,sqlite3_uint64,
+                     void(*)(void*));
+  int (*bind_text64)(sqlite3_stmt*,int,const char*,sqlite3_uint64,
+                      void(*)(void*),unsigned char);
+  int (*cancel_auto_extension)(void(*)(void));
+  int (*load_extension)(sqlite3*,const char*,const char*,char**);
+  void *(*malloc64)(sqlite3_uint64);
+  sqlite3_uint64 (*msize)(void*);
+  void *(*realloc64)(void*,sqlite3_uint64);
+  void (*reset_auto_extension)(void);
+  void (*result_blob64)(sqlite3_context*,const void*,sqlite3_uint64,
+                        void(*)(void*));
+  void (*result_text64)(sqlite3_context*,const char*,sqlite3_uint64,
+                         void(*)(void*), unsigned char);
+  int (*strglob)(const char*,const char*);
+  /* Version 3.8.11 and later */
+  sqlite3_value *(*value_dup)(const sqlite3_value*);
+  void (*value_free)(sqlite3_value*);
+  int (*result_zeroblob64)(sqlite3_context*,sqlite3_uint64);
+  int (*bind_zeroblob64)(sqlite3_stmt*, int, sqlite3_uint64);
+  /* Version 3.9.0 and later */
+  unsigned int (*value_subtype)(sqlite3_value*);
+  void (*result_subtype)(sqlite3_context*,unsigned int);
+  /* Version 3.10.0 and later */
+  int (*status64)(int,sqlite3_int64*,sqlite3_int64*,int);
+  int (*strlike)(const char*,const char*,unsigned int);
+  int (*db_cacheflush)(sqlite3*);
+  /* Version 3.12.0 and later */
+  int (*system_errno)(sqlite3*);
+  /* Version 3.14.0 and later */
+  int (*trace_v2)(sqlite3*,unsigned,int(*)(unsigned,void*,void*,void*),void*);
+  char *(*expanded_sql)(sqlite3_stmt*);
+  /* Version 3.18.0 and later */
+  void (*set_last_insert_rowid)(sqlite3*,sqlite3_int64);
+  /* Version 3.20.0 and later */
+  int (*prepare_v3)(sqlite3*,const char*,int,unsigned int,
+                    sqlite3_stmt**,const char**);
+  int (*prepare16_v3)(sqlite3*,const void*,int,unsigned int,
+                      sqlite3_stmt**,const void**);
+  int (*bind_pointer)(sqlite3_stmt*,int,void*,const char*,void(*)(void*));
+  void (*result_pointer)(sqlite3_context*,void*,const char*,void(*)(void*));
+  void *(*value_pointer)(sqlite3_value*,const char*);
+  int (*vtab_nochange)(sqlite3_context*);
+  int (*value_nochange)(sqlite3_value*);
+  const char *(*vtab_collation)(sqlite3_index_info*,int);
+  /* Version 3.24.0 and later */
+  int (*keyword_count)(void);
+  int (*keyword_name)(int,const char**,int*);
+  int (*keyword_check)(const char*,int);
+  sqlite3_str *(*str_new)(sqlite3*);
+  char *(*str_finish)(sqlite3_str*);
+  void (*str_appendf)(sqlite3_str*, const char *zFormat, ...);
+  void (*str_vappendf)(sqlite3_str*, const char *zFormat, va_list);
+  void (*str_append)(sqlite3_str*, const char *zIn, int N);
+  void (*str_appendall)(sqlite3_str*, const char *zIn);
+  void (*str_appendchar)(sqlite3_str*, int N, char C);
+  void (*str_reset)(sqlite3_str*);
+  int (*str_errcode)(sqlite3_str*);
+  int (*str_length)(sqlite3_str*);
+  char *(*str_value)(sqlite3_str*);
+  /* Version 3.25.0 and later */
+  int (*create_window_function)(sqlite3*,const char*,int,int,void*,
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void (*xValue)(sqlite3_context*),
+                            void (*xInv)(sqlite3_context*,int,sqlite3_value**),
+                            void(*xDestroy)(void*));
+  /* Version 3.26.0 and later */
+  const char *(*normalized_sql)(sqlite3_stmt*);
+  /* Version 3.28.0 and later */
+  int (*stmt_isexplain)(sqlite3_stmt*);
+  int (*value_frombind)(sqlite3_value*);
+  /* Version 3.30.0 and later */
+  int (*drop_modules)(sqlite3*,const char**);
+  /* Version 3.31.0 and later */
+  sqlite3_int64 (*hard_heap_limit64)(sqlite3_int64);
+  const char *(*uri_key)(const char*,int);
+  const char *(*filename_database)(const char*);
+  const char *(*filename_journal)(const char*);
+  const char *(*filename_wal)(const char*);
+  /* Version 3.32.0 and later */
+  const char *(*create_filename)(const char*,const char*,const char*,
+                           int,const char**);
+  void (*free_filename)(const char*);
+  sqlite3_file *(*database_file_object)(const char*);
+  /* Version 3.34.0 and later */
+  int (*txn_state)(sqlite3*,const char*);
+  /* Version 3.36.1 and later */
+  sqlite3_int64 (*changes64)(sqlite3*);
+  sqlite3_int64 (*total_changes64)(sqlite3*);
+  /* Version 3.37.0 and later */
+  int (*autovacuum_pages)(sqlite3*,
+     unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
+     void*, void(*)(void*));
+  /* Version 3.38.0 and later */
+  int (*error_offset)(sqlite3*);
+  int (*vtab_rhs_value)(sqlite3_index_info*,int,sqlite3_value**);
+  int (*vtab_distinct)(sqlite3_index_info*);
+  int (*vtab_in)(sqlite3_index_info*,int,int);
+  int (*vtab_in_first)(sqlite3_value*,sqlite3_value**);
+  int (*vtab_in_next)(sqlite3_value*,sqlite3_value**);
+  /* Version 3.39.0 and later */
+  int (*deserialize)(sqlite3*,const char*,unsigned char*,
+                     sqlite3_int64,sqlite3_int64,unsigned);
+  unsigned char *(*serialize)(sqlite3*,const char *,sqlite3_int64*,
+                              unsigned int);
+  const char *(*db_name)(sqlite3*,int);
+  /* Version 3.40.0 and later */
+  int (*value_encoding)(sqlite3_value*);
+  /* Version 3.41.0 and later */
+  int (*is_interrupted)(sqlite3*);
+  /* Version 3.43.0 and later */
+  int (*stmt_explain)(sqlite3_stmt*,int);
+  /* Version 3.44.0 and later */
+  void *(*get_clientdata)(sqlite3*,const char*);
+  int (*set_clientdata)(sqlite3*, const char*, void*, void(*)(void*));
+};
+
+/*
+** This is the function signature used for all extension entry points.  It
+** is also defined in the file "loadext.c".
+*/
+typedef int (*sqlite3_loadext_entry)(
+  sqlite3 *db,                       /* Handle to the database. */
+  char **pzErrMsg,                   /* Used to set error string on failure. */
+  const sqlite3_api_routines *pThunk /* Extension API function pointers. */
+);
+
+/*
+** The following macros redefine the API routines so that they are
+** redirected through the global sqlite3_api structure.
+**
+** This header file is also used by the loadext.c source file
+** (part of the main SQLite library - not an extension) so that
+** it can get access to the sqlite3_api_routines structure
+** definition.  But the main library does not want to redefine
+** the API.  So the redefinition macros are only valid if the
+** SQLITE_CORE macros is undefined.
+*/
+#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+#define sqlite3_aggregate_context      sqlite3_api->aggregate_context
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_aggregate_count        sqlite3_api->aggregate_count
+#endif
+#define sqlite3_bind_blob              sqlite3_api->bind_blob
+#define sqlite3_bind_double            sqlite3_api->bind_double
+#define sqlite3_bind_int               sqlite3_api->bind_int
+#define sqlite3_bind_int64             sqlite3_api->bind_int64
+#define sqlite3_bind_null              sqlite3_api->bind_null
+#define sqlite3_bind_parameter_count   sqlite3_api->bind_parameter_count
+#define sqlite3_bind_parameter_index   sqlite3_api->bind_parameter_index
+#define sqlite3_bind_parameter_name    sqlite3_api->bind_parameter_name
+#define sqlite3_bind_text              sqlite3_api->bind_text
+#define sqlite3_bind_text16            sqlite3_api->bind_text16
+#define sqlite3_bind_value             sqlite3_api->bind_value
+#define sqlite3_busy_handler           sqlite3_api->busy_handler
+#define sqlite3_busy_timeout           sqlite3_api->busy_timeout
+#define sqlite3_changes                sqlite3_api->changes
+#define sqlite3_close                  sqlite3_api->close
+#define sqlite3_collation_needed       sqlite3_api->collation_needed
+#define sqlite3_collation_needed16     sqlite3_api->collation_needed16
+#define sqlite3_column_blob            sqlite3_api->column_blob
+#define sqlite3_column_bytes           sqlite3_api->column_bytes
+#define sqlite3_column_bytes16         sqlite3_api->column_bytes16
+#define sqlite3_column_count           sqlite3_api->column_count
+#define sqlite3_column_database_name   sqlite3_api->column_database_name
+#define sqlite3_column_database_name16 sqlite3_api->column_database_name16
+#define sqlite3_column_decltype        sqlite3_api->column_decltype
+#define sqlite3_column_decltype16      sqlite3_api->column_decltype16
+#define sqlite3_column_double          sqlite3_api->column_double
+#define sqlite3_column_int             sqlite3_api->column_int
+#define sqlite3_column_int64           sqlite3_api->column_int64
+#define sqlite3_column_name            sqlite3_api->column_name
+#define sqlite3_column_name16          sqlite3_api->column_name16
+#define sqlite3_column_origin_name     sqlite3_api->column_origin_name
+#define sqlite3_column_origin_name16   sqlite3_api->column_origin_name16
+#define sqlite3_column_table_name      sqlite3_api->column_table_name
+#define sqlite3_column_table_name16    sqlite3_api->column_table_name16
+#define sqlite3_column_text            sqlite3_api->column_text
+#define sqlite3_column_text16          sqlite3_api->column_text16
+#define sqlite3_column_type            sqlite3_api->column_type
+#define sqlite3_column_value           sqlite3_api->column_value
+#define sqlite3_commit_hook            sqlite3_api->commit_hook
+#define sqlite3_complete               sqlite3_api->complete
+#define sqlite3_complete16             sqlite3_api->complete16
+#define sqlite3_create_collation       sqlite3_api->create_collation
+#define sqlite3_create_collation16     sqlite3_api->create_collation16
+#define sqlite3_create_function        sqlite3_api->create_function
+#define sqlite3_create_function16      sqlite3_api->create_function16
+#define sqlite3_create_module          sqlite3_api->create_module
+#define sqlite3_create_module_v2       sqlite3_api->create_module_v2
+#define sqlite3_data_count             sqlite3_api->data_count
+#define sqlite3_db_handle              sqlite3_api->db_handle
+#define sqlite3_declare_vtab           sqlite3_api->declare_vtab
+#define sqlite3_enable_shared_cache    sqlite3_api->enable_shared_cache
+#define sqlite3_errcode                sqlite3_api->errcode
+#define sqlite3_errmsg                 sqlite3_api->errmsg
+#define sqlite3_errmsg16               sqlite3_api->errmsg16
+#define sqlite3_exec                   sqlite3_api->exec
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_expired                sqlite3_api->expired
+#endif
+#define sqlite3_finalize               sqlite3_api->finalize
+#define sqlite3_free                   sqlite3_api->free
+#define sqlite3_free_table             sqlite3_api->free_table
+#define sqlite3_get_autocommit         sqlite3_api->get_autocommit
+#define sqlite3_get_auxdata            sqlite3_api->get_auxdata
+#define sqlite3_get_table              sqlite3_api->get_table
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_global_recover         sqlite3_api->global_recover
+#endif
+#define sqlite3_interrupt              sqlite3_api->interruptx
+#define sqlite3_last_insert_rowid      sqlite3_api->last_insert_rowid
+#define sqlite3_libversion             sqlite3_api->libversion
+#define sqlite3_libversion_number      sqlite3_api->libversion_number
+#define sqlite3_malloc                 sqlite3_api->malloc
+#define sqlite3_mprintf                sqlite3_api->mprintf
+#define sqlite3_open                   sqlite3_api->open
+#define sqlite3_open16                 sqlite3_api->open16
+#define sqlite3_prepare                sqlite3_api->prepare
+#define sqlite3_prepare16              sqlite3_api->prepare16
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_profile                sqlite3_api->profile
+#define sqlite3_progress_handler       sqlite3_api->progress_handler
+#define sqlite3_realloc                sqlite3_api->realloc
+#define sqlite3_reset                  sqlite3_api->reset
+#define sqlite3_result_blob            sqlite3_api->result_blob
+#define sqlite3_result_double          sqlite3_api->result_double
+#define sqlite3_result_error           sqlite3_api->result_error
+#define sqlite3_result_error16         sqlite3_api->result_error16
+#define sqlite3_result_int             sqlite3_api->result_int
+#define sqlite3_result_int64           sqlite3_api->result_int64
+#define sqlite3_result_null            sqlite3_api->result_null
+#define sqlite3_result_text            sqlite3_api->result_text
+#define sqlite3_result_text16          sqlite3_api->result_text16
+#define sqlite3_result_text16be        sqlite3_api->result_text16be
+#define sqlite3_result_text16le        sqlite3_api->result_text16le
+#define sqlite3_result_value           sqlite3_api->result_value
+#define sqlite3_rollback_hook          sqlite3_api->rollback_hook
+#define sqlite3_set_authorizer         sqlite3_api->set_authorizer
+#define sqlite3_set_auxdata            sqlite3_api->set_auxdata
+#define sqlite3_snprintf               sqlite3_api->xsnprintf
+#define sqlite3_step                   sqlite3_api->step
+#define sqlite3_table_column_metadata  sqlite3_api->table_column_metadata
+#define sqlite3_thread_cleanup         sqlite3_api->thread_cleanup
+#define sqlite3_total_changes          sqlite3_api->total_changes
+#define sqlite3_trace                  sqlite3_api->trace
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_transfer_bindings      sqlite3_api->transfer_bindings
+#endif
+#define sqlite3_update_hook            sqlite3_api->update_hook
+#define sqlite3_user_data              sqlite3_api->user_data
+#define sqlite3_value_blob             sqlite3_api->value_blob
+#define sqlite3_value_bytes            sqlite3_api->value_bytes
+#define sqlite3_value_bytes16          sqlite3_api->value_bytes16
+#define sqlite3_value_double           sqlite3_api->value_double
+#define sqlite3_value_int              sqlite3_api->value_int
+#define sqlite3_value_int64            sqlite3_api->value_int64
+#define sqlite3_value_numeric_type     sqlite3_api->value_numeric_type
+#define sqlite3_value_text             sqlite3_api->value_text
+#define sqlite3_value_text16           sqlite3_api->value_text16
+#define sqlite3_value_text16be         sqlite3_api->value_text16be
+#define sqlite3_value_text16le         sqlite3_api->value_text16le
+#define sqlite3_value_type             sqlite3_api->value_type
+#define sqlite3_vmprintf               sqlite3_api->vmprintf
+#define sqlite3_vsnprintf              sqlite3_api->xvsnprintf
+#define sqlite3_overload_function      sqlite3_api->overload_function
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_clear_bindings         sqlite3_api->clear_bindings
+#define sqlite3_bind_zeroblob          sqlite3_api->bind_zeroblob
+#define sqlite3_blob_bytes             sqlite3_api->blob_bytes
+#define sqlite3_blob_close             sqlite3_api->blob_close
+#define sqlite3_blob_open              sqlite3_api->blob_open
+#define sqlite3_blob_read              sqlite3_api->blob_read
+#define sqlite3_blob_write             sqlite3_api->blob_write
+#define sqlite3_create_collation_v2    sqlite3_api->create_collation_v2
+#define sqlite3_file_control           sqlite3_api->file_control
+#define sqlite3_memory_highwater       sqlite3_api->memory_highwater
+#define sqlite3_memory_used            sqlite3_api->memory_used
+#define sqlite3_mutex_alloc            sqlite3_api->mutex_alloc
+#define sqlite3_mutex_enter            sqlite3_api->mutex_enter
+#define sqlite3_mutex_free             sqlite3_api->mutex_free
+#define sqlite3_mutex_leave            sqlite3_api->mutex_leave
+#define sqlite3_mutex_try              sqlite3_api->mutex_try
+#define sqlite3_open_v2                sqlite3_api->open_v2
+#define sqlite3_release_memory         sqlite3_api->release_memory
+#define sqlite3_result_error_nomem     sqlite3_api->result_error_nomem
+#define sqlite3_result_error_toobig    sqlite3_api->result_error_toobig
+#define sqlite3_sleep                  sqlite3_api->sleep
+#define sqlite3_soft_heap_limit        sqlite3_api->soft_heap_limit
+#define sqlite3_vfs_find               sqlite3_api->vfs_find
+#define sqlite3_vfs_register           sqlite3_api->vfs_register
+#define sqlite3_vfs_unregister         sqlite3_api->vfs_unregister
+#define sqlite3_threadsafe             sqlite3_api->xthreadsafe
+#define sqlite3_result_zeroblob        sqlite3_api->result_zeroblob
+#define sqlite3_result_error_code      sqlite3_api->result_error_code
+#define sqlite3_test_control           sqlite3_api->test_control
+#define sqlite3_randomness             sqlite3_api->randomness
+#define sqlite3_context_db_handle      sqlite3_api->context_db_handle
+#define sqlite3_extended_result_codes  sqlite3_api->extended_result_codes
+#define sqlite3_limit                  sqlite3_api->limit
+#define sqlite3_next_stmt              sqlite3_api->next_stmt
+#define sqlite3_sql                    sqlite3_api->sql
+#define sqlite3_status                 sqlite3_api->status
+#define sqlite3_backup_finish          sqlite3_api->backup_finish
+#define sqlite3_backup_init            sqlite3_api->backup_init
+#define sqlite3_backup_pagecount       sqlite3_api->backup_pagecount
+#define sqlite3_backup_remaining       sqlite3_api->backup_remaining
+#define sqlite3_backup_step            sqlite3_api->backup_step
+#define sqlite3_compileoption_get      sqlite3_api->compileoption_get
+#define sqlite3_compileoption_used     sqlite3_api->compileoption_used
+#define sqlite3_create_function_v2     sqlite3_api->create_function_v2
+#define sqlite3_db_config              sqlite3_api->db_config
+#define sqlite3_db_mutex               sqlite3_api->db_mutex
+#define sqlite3_db_status              sqlite3_api->db_status
+#define sqlite3_extended_errcode       sqlite3_api->extended_errcode
+#define sqlite3_log                    sqlite3_api->log
+#define sqlite3_soft_heap_limit64      sqlite3_api->soft_heap_limit64
+#define sqlite3_sourceid               sqlite3_api->sourceid
+#define sqlite3_stmt_status            sqlite3_api->stmt_status
+#define sqlite3_strnicmp               sqlite3_api->strnicmp
+#define sqlite3_unlock_notify          sqlite3_api->unlock_notify
+#define sqlite3_wal_autocheckpoint     sqlite3_api->wal_autocheckpoint
+#define sqlite3_wal_checkpoint         sqlite3_api->wal_checkpoint
+#define sqlite3_wal_hook               sqlite3_api->wal_hook
+#define sqlite3_blob_reopen            sqlite3_api->blob_reopen
+#define sqlite3_vtab_config            sqlite3_api->vtab_config
+#define sqlite3_vtab_on_conflict       sqlite3_api->vtab_on_conflict
+/* Version 3.7.16 and later */
+#define sqlite3_close_v2               sqlite3_api->close_v2
+#define sqlite3_db_filename            sqlite3_api->db_filename
+#define sqlite3_db_readonly            sqlite3_api->db_readonly
+#define sqlite3_db_release_memory      sqlite3_api->db_release_memory
+#define sqlite3_errstr                 sqlite3_api->errstr
+#define sqlite3_stmt_busy              sqlite3_api->stmt_busy
+#define sqlite3_stmt_readonly          sqlite3_api->stmt_readonly
+#define sqlite3_stricmp                sqlite3_api->stricmp
+#define sqlite3_uri_boolean            sqlite3_api->uri_boolean
+#define sqlite3_uri_int64              sqlite3_api->uri_int64
+#define sqlite3_uri_parameter          sqlite3_api->uri_parameter
+#define sqlite3_uri_vsnprintf          sqlite3_api->xvsnprintf
+#define sqlite3_wal_checkpoint_v2      sqlite3_api->wal_checkpoint_v2
+/* Version 3.8.7 and later */
+#define sqlite3_auto_extension         sqlite3_api->auto_extension
+#define sqlite3_bind_blob64            sqlite3_api->bind_blob64
+#define sqlite3_bind_text64            sqlite3_api->bind_text64
+#define sqlite3_cancel_auto_extension  sqlite3_api->cancel_auto_extension
+#define sqlite3_load_extension         sqlite3_api->load_extension
+#define sqlite3_malloc64               sqlite3_api->malloc64
+#define sqlite3_msize                  sqlite3_api->msize
+#define sqlite3_realloc64              sqlite3_api->realloc64
+#define sqlite3_reset_auto_extension   sqlite3_api->reset_auto_extension
+#define sqlite3_result_blob64          sqlite3_api->result_blob64
+#define sqlite3_result_text64          sqlite3_api->result_text64
+#define sqlite3_strglob                sqlite3_api->strglob
+/* Version 3.8.11 and later */
+#define sqlite3_value_dup              sqlite3_api->value_dup
+#define sqlite3_value_free             sqlite3_api->value_free
+#define sqlite3_result_zeroblob64      sqlite3_api->result_zeroblob64
+#define sqlite3_bind_zeroblob64        sqlite3_api->bind_zeroblob64
+/* Version 3.9.0 and later */
+#define sqlite3_value_subtype          sqlite3_api->value_subtype
+#define sqlite3_result_subtype         sqlite3_api->result_subtype
+/* Version 3.10.0 and later */
+#define sqlite3_status64               sqlite3_api->status64
+#define sqlite3_strlike                sqlite3_api->strlike
+#define sqlite3_db_cacheflush          sqlite3_api->db_cacheflush
+/* Version 3.12.0 and later */
+#define sqlite3_system_errno           sqlite3_api->system_errno
+/* Version 3.14.0 and later */
+#define sqlite3_trace_v2               sqlite3_api->trace_v2
+#define sqlite3_expanded_sql           sqlite3_api->expanded_sql
+/* Version 3.18.0 and later */
+#define sqlite3_set_last_insert_rowid  sqlite3_api->set_last_insert_rowid
+/* Version 3.20.0 and later */
+#define sqlite3_prepare_v3             sqlite3_api->prepare_v3
+#define sqlite3_prepare16_v3           sqlite3_api->prepare16_v3
+#define sqlite3_bind_pointer           sqlite3_api->bind_pointer
+#define sqlite3_result_pointer         sqlite3_api->result_pointer
+#define sqlite3_value_pointer          sqlite3_api->value_pointer
+/* Version 3.22.0 and later */
+#define sqlite3_vtab_nochange          sqlite3_api->vtab_nochange
+#define sqlite3_value_nochange         sqlite3_api->value_nochange
+#define sqlite3_vtab_collation         sqlite3_api->vtab_collation
+/* Version 3.24.0 and later */
+#define sqlite3_keyword_count          sqlite3_api->keyword_count
+#define sqlite3_keyword_name           sqlite3_api->keyword_name
+#define sqlite3_keyword_check          sqlite3_api->keyword_check
+#define sqlite3_str_new                sqlite3_api->str_new
+#define sqlite3_str_finish             sqlite3_api->str_finish
+#define sqlite3_str_appendf            sqlite3_api->str_appendf
+#define sqlite3_str_vappendf           sqlite3_api->str_vappendf
+#define sqlite3_str_append             sqlite3_api->str_append
+#define sqlite3_str_appendall          sqlite3_api->str_appendall
+#define sqlite3_str_appendchar         sqlite3_api->str_appendchar
+#define sqlite3_str_reset              sqlite3_api->str_reset
+#define sqlite3_str_errcode            sqlite3_api->str_errcode
+#define sqlite3_str_length             sqlite3_api->str_length
+#define sqlite3_str_value              sqlite3_api->str_value
+/* Version 3.25.0 and later */
+#define sqlite3_create_window_function sqlite3_api->create_window_function
+/* Version 3.26.0 and later */
+#define sqlite3_normalized_sql         sqlite3_api->normalized_sql
+/* Version 3.28.0 and later */
+#define sqlite3_stmt_isexplain         sqlite3_api->stmt_isexplain
+#define sqlite3_value_frombind         sqlite3_api->value_frombind
+/* Version 3.30.0 and later */
+#define sqlite3_drop_modules           sqlite3_api->drop_modules
+/* Version 3.31.0 and later */
+#define sqlite3_hard_heap_limit64      sqlite3_api->hard_heap_limit64
+#define sqlite3_uri_key                sqlite3_api->uri_key
+#define sqlite3_filename_database      sqlite3_api->filename_database
+#define sqlite3_filename_journal       sqlite3_api->filename_journal
+#define sqlite3_filename_wal           sqlite3_api->filename_wal
+/* Version 3.32.0 and later */
+#define sqlite3_create_filename        sqlite3_api->create_filename
+#define sqlite3_free_filename          sqlite3_api->free_filename
+#define sqlite3_database_file_object   sqlite3_api->database_file_object
+/* Version 3.34.0 and later */
+#define sqlite3_txn_state              sqlite3_api->txn_state
+/* Version 3.36.1 and later */
+#define sqlite3_changes64              sqlite3_api->changes64
+#define sqlite3_total_changes64        sqlite3_api->total_changes64
+/* Version 3.37.0 and later */
+#define sqlite3_autovacuum_pages       sqlite3_api->autovacuum_pages
+/* Version 3.38.0 and later */
+#define sqlite3_error_offset           sqlite3_api->error_offset
+#define sqlite3_vtab_rhs_value         sqlite3_api->vtab_rhs_value
+#define sqlite3_vtab_distinct          sqlite3_api->vtab_distinct
+#define sqlite3_vtab_in                sqlite3_api->vtab_in
+#define sqlite3_vtab_in_first          sqlite3_api->vtab_in_first
+#define sqlite3_vtab_in_next           sqlite3_api->vtab_in_next
+/* Version 3.39.0 and later */
+#ifndef SQLITE_OMIT_DESERIALIZE
+#define sqlite3_deserialize            sqlite3_api->deserialize
+#define sqlite3_serialize              sqlite3_api->serialize
+#endif
+#define sqlite3_db_name                sqlite3_api->db_name
+/* Version 3.40.0 and later */
+#define sqlite3_value_encoding         sqlite3_api->value_encoding
+/* Version 3.41.0 and later */
+#define sqlite3_is_interrupted         sqlite3_api->is_interrupted
+/* Version 3.43.0 and later */
+#define sqlite3_stmt_explain           sqlite3_api->stmt_explain
+/* Version 3.44.0 and later */
+#define sqlite3_get_clientdata         sqlite3_api->get_clientdata
+#define sqlite3_set_clientdata         sqlite3_api->set_clientdata
+#endif /* !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION) */
+
+#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  /* This case when the file really is being compiled as a loadable
+  ** extension */
+# define SQLITE_EXTENSION_INIT1     const sqlite3_api_routines *sqlite3_api=0;
+# define SQLITE_EXTENSION_INIT2(v)  sqlite3_api=v;
+# define SQLITE_EXTENSION_INIT3     \
+    extern const sqlite3_api_routines *sqlite3_api;
+#else
+  /* This case when the file is being statically linked into the
+  ** application */
+# define SQLITE_EXTENSION_INIT1     /*no-op*/
+# define SQLITE_EXTENSION_INIT2(v)  (void)v; /* unused parameter */
+# define SQLITE_EXTENSION_INIT3     /*no-op*/
+#endif
+
+#endif /* SQLITE3EXT_H */
+
+/************** End of sqlite3ext.h ******************************************/
+/************** Continuing where we left off in loadext.c ********************/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Some API routines are omitted when various features are
+** excluded from a build of SQLite.  Substitute a NULL pointer
+** for any missing APIs.
+*/
+#ifndef SQLITE_ENABLE_COLUMN_METADATA
+# define sqlite3_column_database_name   0
+# define sqlite3_column_database_name16 0
+# define sqlite3_column_table_name      0
+# define sqlite3_column_table_name16    0
+# define sqlite3_column_origin_name     0
+# define sqlite3_column_origin_name16   0
+#endif
+
+#ifdef SQLITE_OMIT_AUTHORIZATION
+# define sqlite3_set_authorizer         0
+#endif
+
+#ifdef SQLITE_OMIT_UTF16
+# define sqlite3_bind_text16            0
+# define sqlite3_collation_needed16     0
+# define sqlite3_column_decltype16      0
+# define sqlite3_column_name16          0
+# define sqlite3_column_text16          0
+# define sqlite3_complete16             0
+# define sqlite3_create_collation16     0
+# define sqlite3_create_function16      0
+# define sqlite3_errmsg16               0
+# define sqlite3_open16                 0
+# define sqlite3_prepare16              0
+# define sqlite3_prepare16_v2           0
+# define sqlite3_prepare16_v3           0
+# define sqlite3_result_error16         0
+# define sqlite3_result_text16          0
+# define sqlite3_result_text16be        0
+# define sqlite3_result_text16le        0
+# define sqlite3_value_text16           0
+# define sqlite3_value_text16be         0
+# define sqlite3_value_text16le         0
+# define sqlite3_column_database_name16 0
+# define sqlite3_column_table_name16    0
+# define sqlite3_column_origin_name16   0
+#endif
+
+#ifdef SQLITE_OMIT_COMPLETE
+# define sqlite3_complete 0
+# define sqlite3_complete16 0
+#endif
+
+#ifdef SQLITE_OMIT_DECLTYPE
+# define sqlite3_column_decltype16      0
+# define sqlite3_column_decltype        0
+#endif
+
+#ifdef SQLITE_OMIT_PROGRESS_CALLBACK
+# define sqlite3_progress_handler 0
+#endif
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+# define sqlite3_create_module 0
+# define sqlite3_create_module_v2 0
+# define sqlite3_declare_vtab 0
+# define sqlite3_vtab_config 0
+# define sqlite3_vtab_on_conflict 0
+# define sqlite3_vtab_collation 0
+#endif
+
+#ifdef SQLITE_OMIT_SHARED_CACHE
+# define sqlite3_enable_shared_cache 0
+#endif
+
+#if defined(SQLITE_OMIT_TRACE) || defined(SQLITE_OMIT_DEPRECATED)
+# define sqlite3_profile       0
+# define sqlite3_trace         0
+#endif
+
+#ifdef SQLITE_OMIT_GET_TABLE
+# define sqlite3_free_table    0
+# define sqlite3_get_table     0
+#endif
+
+#ifdef SQLITE_OMIT_INCRBLOB
+#define sqlite3_bind_zeroblob  0
+#define sqlite3_blob_bytes     0
+#define sqlite3_blob_close     0
+#define sqlite3_blob_open      0
+#define sqlite3_blob_read      0
+#define sqlite3_blob_write     0
+#define sqlite3_blob_reopen    0
+#endif
+
+#if defined(SQLITE_OMIT_TRACE)
+# define sqlite3_trace_v2      0
+#endif
+
+/*
+** The following structure contains pointers to all SQLite API routines.
+** A pointer to this structure is passed into extensions when they are
+** loaded so that the extension can make calls back into the SQLite
+** library.
+**
+** When adding new APIs, add them to the bottom of this structure
+** in order to preserve backwards compatibility.
+**
+** Extensions that use newer APIs should first call the
+** sqlite3_libversion_number() to make sure that the API they
+** intend to use is supported by the library.  Extensions should
+** also check to make sure that the pointer to the function is
+** not NULL before calling it.
+*/
+static const sqlite3_api_routines sqlite3Apis = {
+  sqlite3_aggregate_context,
+#ifndef SQLITE_OMIT_DEPRECATED
+  sqlite3_aggregate_count,
+#else
+  0,
+#endif
+  sqlite3_bind_blob,
+  sqlite3_bind_double,
+  sqlite3_bind_int,
+  sqlite3_bind_int64,
+  sqlite3_bind_null,
+  sqlite3_bind_parameter_count,
+  sqlite3_bind_parameter_index,
+  sqlite3_bind_parameter_name,
+  sqlite3_bind_text,
+  sqlite3_bind_text16,
+  sqlite3_bind_value,
+  sqlite3_busy_handler,
+  sqlite3_busy_timeout,
+  sqlite3_changes,
+  sqlite3_close,
+  sqlite3_collation_needed,
+  sqlite3_collation_needed16,
+  sqlite3_column_blob,
+  sqlite3_column_bytes,
+  sqlite3_column_bytes16,
+  sqlite3_column_count,
+  sqlite3_column_database_name,
+  sqlite3_column_database_name16,
+  sqlite3_column_decltype,
+  sqlite3_column_decltype16,
+  sqlite3_column_double,
+  sqlite3_column_int,
+  sqlite3_column_int64,
+  sqlite3_column_name,
+  sqlite3_column_name16,
+  sqlite3_column_origin_name,
+  sqlite3_column_origin_name16,
+  sqlite3_column_table_name,
+  sqlite3_column_table_name16,
+  sqlite3_column_text,
+  sqlite3_column_text16,
+  sqlite3_column_type,
+  sqlite3_column_value,
+  sqlite3_commit_hook,
+  sqlite3_complete,
+  sqlite3_complete16,
+  sqlite3_create_collation,
+  sqlite3_create_collation16,
+  sqlite3_create_function,
+  sqlite3_create_function16,
+  sqlite3_create_module,
+  sqlite3_data_count,
+  sqlite3_db_handle,
+  sqlite3_declare_vtab,
+  sqlite3_enable_shared_cache,
+  sqlite3_errcode,
+  sqlite3_errmsg,
+  sqlite3_errmsg16,
+  sqlite3_exec,
+#ifndef SQLITE_OMIT_DEPRECATED
+  sqlite3_expired,
+#else
+  0,
+#endif
+  sqlite3_finalize,
+  sqlite3_free,
+  sqlite3_free_table,
+  sqlite3_get_autocommit,
+  sqlite3_get_auxdata,
+  sqlite3_get_table,
+  0,     /* Was sqlite3_global_recover(), but that function is deprecated */
+  sqlite3_interrupt,
+  sqlite3_last_insert_rowid,
+  sqlite3_libversion,
+  sqlite3_libversion_number,
+  sqlite3_malloc,
+  sqlite3_mprintf,
+  sqlite3_open,
+  sqlite3_open16,
+  sqlite3_prepare,
+  sqlite3_prepare16,
+  sqlite3_profile,
+  sqlite3_progress_handler,
+  sqlite3_realloc,
+  sqlite3_reset,
+  sqlite3_result_blob,
+  sqlite3_result_double,
+  sqlite3_result_error,
+  sqlite3_result_error16,
+  sqlite3_result_int,
+  sqlite3_result_int64,
+  sqlite3_result_null,
+  sqlite3_result_text,
+  sqlite3_result_text16,
+  sqlite3_result_text16be,
+  sqlite3_result_text16le,
+  sqlite3_result_value,
+  sqlite3_rollback_hook,
+  sqlite3_set_authorizer,
+  sqlite3_set_auxdata,
+  sqlite3_snprintf,
+  sqlite3_step,
+  sqlite3_table_column_metadata,
+#ifndef SQLITE_OMIT_DEPRECATED
+  sqlite3_thread_cleanup,
+#else
+  0,
+#endif
+  sqlite3_total_changes,
+  sqlite3_trace,
+#ifndef SQLITE_OMIT_DEPRECATED
+  sqlite3_transfer_bindings,
+#else
+  0,
+#endif
+  sqlite3_update_hook,
+  sqlite3_user_data,
+  sqlite3_value_blob,
+  sqlite3_value_bytes,
+  sqlite3_value_bytes16,
+  sqlite3_value_double,
+  sqlite3_value_int,
+  sqlite3_value_int64,
+  sqlite3_value_numeric_type,
+  sqlite3_value_text,
+  sqlite3_value_text16,
+  sqlite3_value_text16be,
+  sqlite3_value_text16le,
+  sqlite3_value_type,
+  sqlite3_vmprintf,
+  /*
+  ** The original API set ends here.  All extensions can call any
+  ** of the APIs above provided that the pointer is not NULL.  But
+  ** before calling APIs that follow, extension should check the
+  ** sqlite3_libversion_number() to make sure they are dealing with
+  ** a library that is new enough to support that API.
+  *************************************************************************
+  */
+  sqlite3_overload_function,
+
+  /*
+  ** Added after 3.3.13
+  */
+  sqlite3_prepare_v2,
+  sqlite3_prepare16_v2,
+  sqlite3_clear_bindings,
+
+  /*
+  ** Added for 3.4.1
+  */
+  sqlite3_create_module_v2,
+
+  /*
+  ** Added for 3.5.0
+  */
+  sqlite3_bind_zeroblob,
+  sqlite3_blob_bytes,
+  sqlite3_blob_close,
+  sqlite3_blob_open,
+  sqlite3_blob_read,
+  sqlite3_blob_write,
+  sqlite3_create_collation_v2,
+  sqlite3_file_control,
+  sqlite3_memory_highwater,
+  sqlite3_memory_used,
+#ifdef SQLITE_MUTEX_OMIT
+  0,
+  0,
+  0,
+  0,
+  0,
+#else
+  sqlite3_mutex_alloc,
+  sqlite3_mutex_enter,
+  sqlite3_mutex_free,
+  sqlite3_mutex_leave,
+  sqlite3_mutex_try,
+#endif
+  sqlite3_open_v2,
+  sqlite3_release_memory,
+  sqlite3_result_error_nomem,
+  sqlite3_result_error_toobig,
+  sqlite3_sleep,
+  sqlite3_soft_heap_limit,
+  sqlite3_vfs_find,
+  sqlite3_vfs_register,
+  sqlite3_vfs_unregister,
+
+  /*
+  ** Added for 3.5.8
+  */
+  sqlite3_threadsafe,
+  sqlite3_result_zeroblob,
+  sqlite3_result_error_code,
+  sqlite3_test_control,
+  sqlite3_randomness,
+  sqlite3_context_db_handle,
+
+  /*
+  ** Added for 3.6.0
+  */
+  sqlite3_extended_result_codes,
+  sqlite3_limit,
+  sqlite3_next_stmt,
+  sqlite3_sql,
+  sqlite3_status,
+
+  /*
+  ** Added for 3.7.4
+  */
+  sqlite3_backup_finish,
+  sqlite3_backup_init,
+  sqlite3_backup_pagecount,
+  sqlite3_backup_remaining,
+  sqlite3_backup_step,
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+  sqlite3_compileoption_get,
+  sqlite3_compileoption_used,
+#else
+  0,
+  0,
+#endif
+  sqlite3_create_function_v2,
+  sqlite3_db_config,
+  sqlite3_db_mutex,
+  sqlite3_db_status,
+  sqlite3_extended_errcode,
+  sqlite3_log,
+  sqlite3_soft_heap_limit64,
+  sqlite3_sourceid,
+  sqlite3_stmt_status,
+  sqlite3_strnicmp,
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+  sqlite3_unlock_notify,
+#else
+  0,
+#endif
+#ifndef SQLITE_OMIT_WAL
+  sqlite3_wal_autocheckpoint,
+  sqlite3_wal_checkpoint,
+  sqlite3_wal_hook,
+#else
+  0,
+  0,
+  0,
+#endif
+  sqlite3_blob_reopen,
+  sqlite3_vtab_config,
+  sqlite3_vtab_on_conflict,
+  sqlite3_close_v2,
+  sqlite3_db_filename,
+  sqlite3_db_readonly,
+  sqlite3_db_release_memory,
+  sqlite3_errstr,
+  sqlite3_stmt_busy,
+  sqlite3_stmt_readonly,
+  sqlite3_stricmp,
+  sqlite3_uri_boolean,
+  sqlite3_uri_int64,
+  sqlite3_uri_parameter,
+  sqlite3_vsnprintf,
+  sqlite3_wal_checkpoint_v2,
+  /* Version 3.8.7 and later */
+  sqlite3_auto_extension,
+  sqlite3_bind_blob64,
+  sqlite3_bind_text64,
+  sqlite3_cancel_auto_extension,
+  sqlite3_load_extension,
+  sqlite3_malloc64,
+  sqlite3_msize,
+  sqlite3_realloc64,
+  sqlite3_reset_auto_extension,
+  sqlite3_result_blob64,
+  sqlite3_result_text64,
+  sqlite3_strglob,
+  /* Version 3.8.11 and later */
+  (sqlite3_value*(*)(const sqlite3_value*))sqlite3_value_dup,
+  sqlite3_value_free,
+  sqlite3_result_zeroblob64,
+  sqlite3_bind_zeroblob64,
+  /* Version 3.9.0 and later */
+  sqlite3_value_subtype,
+  sqlite3_result_subtype,
+  /* Version 3.10.0 and later */
+  sqlite3_status64,
+  sqlite3_strlike,
+  sqlite3_db_cacheflush,
+  /* Version 3.12.0 and later */
+  sqlite3_system_errno,
+  /* Version 3.14.0 and later */
+  sqlite3_trace_v2,
+  sqlite3_expanded_sql,
+  /* Version 3.18.0 and later */
+  sqlite3_set_last_insert_rowid,
+  /* Version 3.20.0 and later */
+  sqlite3_prepare_v3,
+  sqlite3_prepare16_v3,
+  sqlite3_bind_pointer,
+  sqlite3_result_pointer,
+  sqlite3_value_pointer,
+  /* Version 3.22.0 and later */
+  sqlite3_vtab_nochange,
+  sqlite3_value_nochange,
+  sqlite3_vtab_collation,
+  /* Version 3.24.0 and later */
+  sqlite3_keyword_count,
+  sqlite3_keyword_name,
+  sqlite3_keyword_check,
+  sqlite3_str_new,
+  sqlite3_str_finish,
+  sqlite3_str_appendf,
+  sqlite3_str_vappendf,
+  sqlite3_str_append,
+  sqlite3_str_appendall,
+  sqlite3_str_appendchar,
+  sqlite3_str_reset,
+  sqlite3_str_errcode,
+  sqlite3_str_length,
+  sqlite3_str_value,
+  /* Version 3.25.0 and later */
+  sqlite3_create_window_function,
+  /* Version 3.26.0 and later */
+#ifdef SQLITE_ENABLE_NORMALIZE
+  sqlite3_normalized_sql,
+#else
+  0,
+#endif
+  /* Version 3.28.0 and later */
+  sqlite3_stmt_isexplain,
+  sqlite3_value_frombind,
+  /* Version 3.30.0 and later */
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3_drop_modules,
+#else
+  0,
+#endif
+  /* Version 3.31.0 and later */
+  sqlite3_hard_heap_limit64,
+  sqlite3_uri_key,
+  sqlite3_filename_database,
+  sqlite3_filename_journal,
+  sqlite3_filename_wal,
+  /* Version 3.32.0 and later */
+  sqlite3_create_filename,
+  sqlite3_free_filename,
+  sqlite3_database_file_object,
+  /* Version 3.34.0 and later */
+  sqlite3_txn_state,
+  /* Version 3.36.1 and later */
+  sqlite3_changes64,
+  sqlite3_total_changes64,
+  /* Version 3.37.0 and later */
+  sqlite3_autovacuum_pages,
+  /* Version 3.38.0 and later */
+  sqlite3_error_offset,
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3_vtab_rhs_value,
+  sqlite3_vtab_distinct,
+  sqlite3_vtab_in,
+  sqlite3_vtab_in_first,
+  sqlite3_vtab_in_next,
+#else
+  0,
+  0,
+  0,
+  0,
+  0,
+#endif
+  /* Version 3.39.0 and later */
+#ifndef SQLITE_OMIT_DESERIALIZE
+  sqlite3_deserialize,
+  sqlite3_serialize,
+#else
+  0,
+  0,
+#endif
+  sqlite3_db_name,
+  /* Version 3.40.0 and later */
+  sqlite3_value_encoding,
+  /* Version 3.41.0 and later */
+  sqlite3_is_interrupted,
+  /* Version 3.43.0 and later */
+  sqlite3_stmt_explain,
+  /* Version 3.44.0 and later */
+  sqlite3_get_clientdata,
+  sqlite3_set_clientdata
+};
+
+/* True if x is the directory separator character
+*/
+#if SQLITE_OS_WIN
+# define DirSep(X)  ((X)=='/'||(X)=='\\')
+#else
+# define DirSep(X)  ((X)=='/')
+#endif
+
+/*
+** Attempt to load an SQLite extension library contained in the file
+** zFile.  The entry point is zProc.  zProc may be 0 in which case a
+** default entry point name (sqlite3_extension_init) is used.  Use
+** of the default name is recommended.
+**
+** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
+**
+** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
+** error message text.  The calling function should free this memory
+** by calling sqlite3DbFree(db, ).
+*/
+static int sqlite3LoadExtension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+){
+  sqlite3_vfs *pVfs = db->pVfs;
+  void *handle;
+  sqlite3_loadext_entry xInit;
+  char *zErrmsg = 0;
+  const char *zEntry;
+  char *zAltEntry = 0;
+  void **aHandle;
+  u64 nMsg = strlen(zFile);
+  int ii;
+  int rc;
+
+  /* Shared library endings to try if zFile cannot be loaded as written */
+  static const char *azEndings[] = {
+#if SQLITE_OS_WIN
+     "dll"
+#elif defined(__APPLE__)
+     "dylib"
+#else
+     "so"
+#endif
+  };
+
+
+  if( pzErrMsg ) *pzErrMsg = 0;
+
+  /* Ticket #1863.  To avoid a creating security problems for older
+  ** applications that relink against newer versions of SQLite, the
+  ** ability to run load_extension is turned off by default.  One
+  ** must call either sqlite3_enable_load_extension(db) or
+  ** sqlite3_db_config(db, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, 0)
+  ** to turn on extension loading.
+  */
+  if( (db->flags & SQLITE_LoadExtension)==0 ){
+    if( pzErrMsg ){
+      *pzErrMsg = sqlite3_mprintf("not authorized");
+    }
+    return SQLITE_ERROR;
+  }
+
+  zEntry = zProc ? zProc : "sqlite3_extension_init";
+
+  /* tag-20210611-1.  Some dlopen() implementations will segfault if given
+  ** an oversize filename.  Most filesystems have a pathname limit of 4K,
+  ** so limit the extension filename length to about twice that.
+  ** https://sqlite.org/forum/forumpost/08a0d6d9bf
+  **
+  ** Later (2023-03-25): Save an extra 6 bytes for the filename suffix.
+  ** See https://sqlite.org/forum/forumpost/24083b579d.
+  */
+  if( nMsg>SQLITE_MAX_PATHLEN ) goto extension_not_found;
+
+  /* Do not allow sqlite3_load_extension() to link to a copy of the
+  ** running application, by passing in an empty filename. */
+  if( nMsg==0 ) goto extension_not_found;
+
+  handle = sqlite3OsDlOpen(pVfs, zFile);
+#if SQLITE_OS_UNIX || SQLITE_OS_WIN
+  for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
+    char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
+    if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
+    if( nMsg+strlen(azEndings[ii])+1<=SQLITE_MAX_PATHLEN ){
+      handle = sqlite3OsDlOpen(pVfs, zAltFile);
+    }
+    sqlite3_free(zAltFile);
+  }
+#endif
+  if( handle==0 ) goto extension_not_found;
+  xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
+
+  /* If no entry point was specified and the default legacy
+  ** entry point name "sqlite3_extension_init" was not found, then
+  ** construct an entry point name "sqlite3_X_init" where the X is
+  ** replaced by the lowercase value of every ASCII alphabetic
+  ** character in the filename after the last "/" upto the first ".",
+  ** and eliding the first three characters if they are "lib".
+  ** Examples:
+  **
+  **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
+  **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
+  */
+  if( xInit==0 && zProc==0 ){
+    int iFile, iEntry, c;
+    int ncFile = sqlite3Strlen30(zFile);
+    zAltEntry = sqlite3_malloc64(ncFile+30);
+    if( zAltEntry==0 ){
+      sqlite3OsDlClose(pVfs, handle);
+      return SQLITE_NOMEM_BKPT;
+    }
+    memcpy(zAltEntry, "sqlite3_", 8);
+    for(iFile=ncFile-1; iFile>=0 && !DirSep(zFile[iFile]); iFile--){}
+    iFile++;
+    if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
+    for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
+      if( sqlite3Isalpha(c) ){
+        zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
+      }
+    }
+    memcpy(zAltEntry+iEntry, "_init", 6);
+    zEntry = zAltEntry;
+    xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
+  }
+  if( xInit==0 ){
+    if( pzErrMsg ){
+      nMsg += strlen(zEntry) + 300;
+      *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
+      if( zErrmsg ){
+        assert( nMsg<0x7fffffff );  /* zErrmsg would be NULL if not so */
+        sqlite3_snprintf((int)nMsg, zErrmsg,
+            "no entry point [%s] in shared library [%s]", zEntry, zFile);
+        sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
+      }
+    }
+    sqlite3OsDlClose(pVfs, handle);
+    sqlite3_free(zAltEntry);
+    return SQLITE_ERROR;
+  }
+  sqlite3_free(zAltEntry);
+  rc = xInit(db, &zErrmsg, &sqlite3Apis);
+  if( rc ){
+    if( rc==SQLITE_OK_LOAD_PERMANENTLY ) return SQLITE_OK;
+    if( pzErrMsg ){
+      *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
+    }
+    sqlite3_free(zErrmsg);
+    sqlite3OsDlClose(pVfs, handle);
+    return SQLITE_ERROR;
+  }
+
+  /* Append the new shared library handle to the db->aExtension array. */
+  aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
+  if( aHandle==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  if( db->nExtension>0 ){
+    memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
+  }
+  sqlite3DbFree(db, db->aExtension);
+  db->aExtension = aHandle;
+
+  db->aExtension[db->nExtension++] = handle;
+  return SQLITE_OK;
+
+extension_not_found:
+  if( pzErrMsg ){
+    nMsg += 300;
+    *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
+    if( zErrmsg ){
+      assert( nMsg<0x7fffffff );  /* zErrmsg would be NULL if not so */
+      sqlite3_snprintf((int)nMsg, zErrmsg,
+          "unable to open shared library [%.*s]", SQLITE_MAX_PATHLEN, zFile);
+      sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
+    }
+  }
+  return SQLITE_ERROR;
+}
+SQLITE_API int sqlite3_load_extension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+){
+  int rc;
+  sqlite3_mutex_enter(db->mutex);
+  rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Call this routine when the database connection is closing in order
+** to clean up loaded extensions
+*/
+SQLITE_PRIVATE void sqlite3CloseExtensions(sqlite3 *db){
+  int i;
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(i=0; i<db->nExtension; i++){
+    sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
+  }
+  sqlite3DbFree(db, db->aExtension);
+}
+
+/*
+** Enable or disable extension loading.  Extension loading is disabled by
+** default so as not to open security holes in older applications.
+*/
+SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( onoff ){
+    db->flags |= SQLITE_LoadExtension|SQLITE_LoadExtFunc;
+  }else{
+    db->flags &= ~(u64)(SQLITE_LoadExtension|SQLITE_LoadExtFunc);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#endif /* !defined(SQLITE_OMIT_LOAD_EXTENSION) */
+
+/*
+** The following object holds the list of automatically loaded
+** extensions.
+**
+** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MAIN
+** mutex must be held while accessing this list.
+*/
+typedef struct sqlite3AutoExtList sqlite3AutoExtList;
+static SQLITE_WSD struct sqlite3AutoExtList {
+  u32 nExt;              /* Number of entries in aExt[] */
+  void (**aExt)(void);   /* Pointers to the extension init functions */
+} sqlite3Autoext = { 0, 0 };
+
+/* The "wsdAutoext" macro will resolve to the autoextension
+** state vector.  If writable static data is unsupported on the target,
+** we have to locate the state vector at run-time.  In the more common
+** case where writable static data is supported, wsdStat can refer directly
+** to the "sqlite3Autoext" state vector declared above.
+*/
+#ifdef SQLITE_OMIT_WSD
+# define wsdAutoextInit \
+  sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
+# define wsdAutoext x[0]
+#else
+# define wsdAutoextInit
+# define wsdAutoext sqlite3Autoext
+#endif
+
+
+/*
+** Register a statically linked extension that is automatically
+** loaded by every new database connection.
+*/
+SQLITE_API int sqlite3_auto_extension(
+  void (*xInit)(void)
+){
+  int rc = SQLITE_OK;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( xInit==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ){
+    return rc;
+  }else
+#endif
+  {
+    u32 i;
+#if SQLITE_THREADSAFE
+    sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+    wsdAutoextInit;
+    sqlite3_mutex_enter(mutex);
+    for(i=0; i<wsdAutoext.nExt; i++){
+      if( wsdAutoext.aExt[i]==xInit ) break;
+    }
+    if( i==wsdAutoext.nExt ){
+      u64 nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
+      void (**aNew)(void);
+      aNew = sqlite3_realloc64(wsdAutoext.aExt, nByte);
+      if( aNew==0 ){
+        rc = SQLITE_NOMEM_BKPT;
+      }else{
+        wsdAutoext.aExt = aNew;
+        wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
+        wsdAutoext.nExt++;
+      }
+    }
+    sqlite3_mutex_leave(mutex);
+    assert( (rc&0xff)==rc );
+    return rc;
+  }
+}
+
+/*
+** Cancel a prior call to sqlite3_auto_extension.  Remove xInit from the
+** set of routines that is invoked for each new database connection, if it
+** is currently on the list.  If xInit is not on the list, then this
+** routine is a no-op.
+**
+** Return 1 if xInit was found on the list and removed.  Return 0 if xInit
+** was not on the list.
+*/
+SQLITE_API int sqlite3_cancel_auto_extension(
+  void (*xInit)(void)
+){
+#if SQLITE_THREADSAFE
+  sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+  int i;
+  int n = 0;
+  wsdAutoextInit;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( xInit==0 ) return 0;
+#endif
+  sqlite3_mutex_enter(mutex);
+  for(i=(int)wsdAutoext.nExt-1; i>=0; i--){
+    if( wsdAutoext.aExt[i]==xInit ){
+      wsdAutoext.nExt--;
+      wsdAutoext.aExt[i] = wsdAutoext.aExt[wsdAutoext.nExt];
+      n++;
+      break;
+    }
+  }
+  sqlite3_mutex_leave(mutex);
+  return n;
+}
+
+/*
+** Reset the automatic extension loading mechanism.
+*/
+SQLITE_API void sqlite3_reset_auto_extension(void){
+#ifndef SQLITE_OMIT_AUTOINIT
+  if( sqlite3_initialize()==SQLITE_OK )
+#endif
+  {
+#if SQLITE_THREADSAFE
+    sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+    wsdAutoextInit;
+    sqlite3_mutex_enter(mutex);
+    sqlite3_free(wsdAutoext.aExt);
+    wsdAutoext.aExt = 0;
+    wsdAutoext.nExt = 0;
+    sqlite3_mutex_leave(mutex);
+  }
+}
+
+/*
+** Load all automatic extensions.
+**
+** If anything goes wrong, set an error in the database connection.
+*/
+SQLITE_PRIVATE void sqlite3AutoLoadExtensions(sqlite3 *db){
+  u32 i;
+  int go = 1;
+  int rc;
+  sqlite3_loadext_entry xInit;
+
+  wsdAutoextInit;
+  if( wsdAutoext.nExt==0 ){
+    /* Common case: early out without every having to acquire a mutex */
+    return;
+  }
+  for(i=0; go; i++){
+    char *zErrmsg;
+#if SQLITE_THREADSAFE
+    sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
+#endif
+#ifdef SQLITE_OMIT_LOAD_EXTENSION
+    const sqlite3_api_routines *pThunk = 0;
+#else
+    const sqlite3_api_routines *pThunk = &sqlite3Apis;
+#endif
+    sqlite3_mutex_enter(mutex);
+    if( i>=wsdAutoext.nExt ){
+      xInit = 0;
+      go = 0;
+    }else{
+      xInit = (sqlite3_loadext_entry)wsdAutoext.aExt[i];
+    }
+    sqlite3_mutex_leave(mutex);
+    zErrmsg = 0;
+    if( xInit && (rc = xInit(db, &zErrmsg, pThunk))!=0 ){
+      sqlite3ErrorWithMsg(db, rc,
+            "automatic extension loading failed: %s", zErrmsg);
+      go = 0;
+    }
+    sqlite3_free(zErrmsg);
+  }
+}
+
+/************** End of loadext.c *********************************************/
+/************** Begin file pragma.c ******************************************/
+/*
+** 2003 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the PRAGMA command.
+*/
+/* #include "sqliteInt.h" */
+
+#if !defined(SQLITE_ENABLE_LOCKING_STYLE)
+#  if defined(__APPLE__)
+#    define SQLITE_ENABLE_LOCKING_STYLE 1
+#  else
+#    define SQLITE_ENABLE_LOCKING_STYLE 0
+#  endif
+#endif
+
+/***************************************************************************
+** The "pragma.h" include file is an automatically generated file that
+** that includes the PragType_XXXX macro definitions and the aPragmaName[]
+** object.  This ensures that the aPragmaName[] table is arranged in
+** lexicographical order to facility a binary search of the pragma name.
+** Do not edit pragma.h directly.  Edit and rerun the script in at
+** ../tool/mkpragmatab.tcl. */
+/************** Include pragma.h in the middle of pragma.c *******************/
+/************** Begin file pragma.h ******************************************/
+/* DO NOT EDIT!
+** This file is automatically generated by the script at
+** ../tool/mkpragmatab.tcl.  To update the set of pragmas, edit
+** that script and rerun it.
+*/
+
+/* The various pragma types */
+#define PragTyp_ACTIVATE_EXTENSIONS            0
+#define PragTyp_ANALYSIS_LIMIT                 1
+#define PragTyp_HEADER_VALUE                   2
+#define PragTyp_AUTO_VACUUM                    3
+#define PragTyp_FLAG                           4
+#define PragTyp_BUSY_TIMEOUT                   5
+#define PragTyp_CACHE_SIZE                     6
+#define PragTyp_CACHE_SPILL                    7
+#define PragTyp_CASE_SENSITIVE_LIKE            8
+#define PragTyp_COLLATION_LIST                 9
+#define PragTyp_COMPILE_OPTIONS               10
+#define PragTyp_DATA_STORE_DIRECTORY          11
+#define PragTyp_DATABASE_LIST                 12
+#define PragTyp_DEFAULT_CACHE_SIZE            13
+#define PragTyp_ENCODING                      14
+#define PragTyp_FOREIGN_KEY_CHECK             15
+#define PragTyp_FOREIGN_KEY_LIST              16
+#define PragTyp_FUNCTION_LIST                 17
+#define PragTyp_HARD_HEAP_LIMIT               18
+#define PragTyp_INCREMENTAL_VACUUM            19
+#define PragTyp_INDEX_INFO                    20
+#define PragTyp_INDEX_LIST                    21
+#define PragTyp_INTEGRITY_CHECK               22
+#define PragTyp_JOURNAL_MODE                  23
+#define PragTyp_JOURNAL_SIZE_LIMIT            24
+#define PragTyp_LOCK_PROXY_FILE               25
+#define PragTyp_LOCKING_MODE                  26
+#define PragTyp_PAGE_COUNT                    27
+#define PragTyp_MMAP_SIZE                     28
+#define PragTyp_MODULE_LIST                   29
+#define PragTyp_OPTIMIZE                      30
+#define PragTyp_PAGE_SIZE                     31
+#define PragTyp_PRAGMA_LIST                   32
+#define PragTyp_SECURE_DELETE                 33
+#define PragTyp_SHRINK_MEMORY                 34
+#define PragTyp_SOFT_HEAP_LIMIT               35
+#define PragTyp_SYNCHRONOUS                   36
+#define PragTyp_TABLE_INFO                    37
+#define PragTyp_TABLE_LIST                    38
+#define PragTyp_TEMP_STORE                    39
+#define PragTyp_TEMP_STORE_DIRECTORY          40
+#define PragTyp_THREADS                       41
+#define PragTyp_WAL_AUTOCHECKPOINT            42
+#define PragTyp_WAL_CHECKPOINT                43
+#define PragTyp_LOCK_STATUS                   44
+#define PragTyp_STATS                         45
+
+/* Property flags associated with various pragma. */
+#define PragFlg_NeedSchema 0x01 /* Force schema load before running */
+#define PragFlg_NoColumns  0x02 /* OP_ResultRow called with zero columns */
+#define PragFlg_NoColumns1 0x04 /* zero columns if RHS argument is present */
+#define PragFlg_ReadOnly   0x08 /* Read-only HEADER_VALUE */
+#define PragFlg_Result0    0x10 /* Acts as query when no argument */
+#define PragFlg_Result1    0x20 /* Acts as query when has one argument */
+#define PragFlg_SchemaOpt  0x40 /* Schema restricts name search if present */
+#define PragFlg_SchemaReq  0x80 /* Schema required - "main" is default */
+
+/* Names of columns for pragmas that return multi-column result
+** or that return single-column results where the name of the
+** result column is different from the name of the pragma
+*/
+static const char *const pragCName[] = {
+  /*   0 */ "id",          /* Used by: foreign_key_list */
+  /*   1 */ "seq",
+  /*   2 */ "table",
+  /*   3 */ "from",
+  /*   4 */ "to",
+  /*   5 */ "on_update",
+  /*   6 */ "on_delete",
+  /*   7 */ "match",
+  /*   8 */ "cid",         /* Used by: table_xinfo */
+  /*   9 */ "name",
+  /*  10 */ "type",
+  /*  11 */ "notnull",
+  /*  12 */ "dflt_value",
+  /*  13 */ "pk",
+  /*  14 */ "hidden",
+                           /* table_info reuses 8 */
+  /*  15 */ "name",        /* Used by: function_list */
+  /*  16 */ "builtin",
+  /*  17 */ "type",
+  /*  18 */ "enc",
+  /*  19 */ "narg",
+  /*  20 */ "flags",
+  /*  21 */ "schema",      /* Used by: table_list */
+  /*  22 */ "name",
+  /*  23 */ "type",
+  /*  24 */ "ncol",
+  /*  25 */ "wr",
+  /*  26 */ "strict",
+  /*  27 */ "seqno",       /* Used by: index_xinfo */
+  /*  28 */ "cid",
+  /*  29 */ "name",
+  /*  30 */ "desc",
+  /*  31 */ "coll",
+  /*  32 */ "key",
+  /*  33 */ "seq",         /* Used by: index_list */
+  /*  34 */ "name",
+  /*  35 */ "unique",
+  /*  36 */ "origin",
+  /*  37 */ "partial",
+  /*  38 */ "tbl",         /* Used by: stats */
+  /*  39 */ "idx",
+  /*  40 */ "wdth",
+  /*  41 */ "hght",
+  /*  42 */ "flgs",
+  /*  43 */ "table",       /* Used by: foreign_key_check */
+  /*  44 */ "rowid",
+  /*  45 */ "parent",
+  /*  46 */ "fkid",
+  /*  47 */ "busy",        /* Used by: wal_checkpoint */
+  /*  48 */ "log",
+  /*  49 */ "checkpointed",
+  /*  50 */ "seq",         /* Used by: database_list */
+  /*  51 */ "name",
+  /*  52 */ "file",
+                           /* index_info reuses 27 */
+  /*  53 */ "database",    /* Used by: lock_status */
+  /*  54 */ "status",
+                           /* collation_list reuses 33 */
+  /*  55 */ "cache_size",  /* Used by: default_cache_size */
+                           /* module_list pragma_list reuses 9 */
+  /*  56 */ "timeout",     /* Used by: busy_timeout */
+};
+
+/* Definitions of all built-in pragmas */
+typedef struct PragmaName {
+  const char *const zName; /* Name of pragma */
+  u8 ePragTyp;             /* PragTyp_XXX value */
+  u8 mPragFlg;             /* Zero or more PragFlg_XXX values */
+  u8 iPragCName;           /* Start of column names in pragCName[] */
+  u8 nPragCName;           /* Num of col names. 0 means use pragma name */
+  u64 iArg;                /* Extra argument */
+} PragmaName;
+static const PragmaName aPragmaName[] = {
+#if defined(SQLITE_ENABLE_CEROD)
+ {/* zName:     */ "activate_extensions",
+  /* ePragTyp:  */ PragTyp_ACTIVATE_EXTENSIONS,
+  /* ePragFlg:  */ 0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+ {/* zName:     */ "analysis_limit",
+  /* ePragTyp:  */ PragTyp_ANALYSIS_LIMIT,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "application_id",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_NoColumns1|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_APPLICATION_ID },
+#endif
+#if !defined(SQLITE_OMIT_AUTOVACUUM)
+ {/* zName:     */ "auto_vacuum",
+  /* ePragTyp:  */ PragTyp_AUTO_VACUUM,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if !defined(SQLITE_OMIT_AUTOMATIC_INDEX)
+ {/* zName:     */ "automatic_index",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_AutoIndex },
+#endif
+#endif
+ {/* zName:     */ "busy_timeout",
+  /* ePragTyp:  */ PragTyp_BUSY_TIMEOUT,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 56, 1,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "cache_size",
+  /* ePragTyp:  */ PragTyp_CACHE_SIZE,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "cache_spill",
+  /* ePragTyp:  */ PragTyp_CACHE_SPILL,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_CASE_SENSITIVE_LIKE_PRAGMA)
+ {/* zName:     */ "case_sensitive_like",
+  /* ePragTyp:  */ PragTyp_CASE_SENSITIVE_LIKE,
+  /* ePragFlg:  */ PragFlg_NoColumns,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+ {/* zName:     */ "cell_size_check",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_CellSizeCk },
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "checkpoint_fullfsync",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_CkptFullFSync },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+ {/* zName:     */ "collation_list",
+  /* ePragTyp:  */ PragTyp_COLLATION_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 33, 2,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_COMPILEOPTION_DIAGS)
+ {/* zName:     */ "compile_options",
+  /* ePragTyp:  */ PragTyp_COMPILE_OPTIONS,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "count_changes",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_CountRows },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && SQLITE_OS_WIN
+ {/* zName:     */ "data_store_directory",
+  /* ePragTyp:  */ PragTyp_DATA_STORE_DIRECTORY,
+  /* ePragFlg:  */ PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "data_version",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_ReadOnly|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_DATA_VERSION },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+ {/* zName:     */ "database_list",
+  /* ePragTyp:  */ PragTyp_DATABASE_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 50, 3,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)
+ {/* zName:     */ "default_cache_size",
+  /* ePragTyp:  */ PragTyp_DEFAULT_CACHE_SIZE,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 55, 1,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+ {/* zName:     */ "defer_foreign_keys",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_DeferFKs },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "empty_result_callbacks",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_NullCallback },
+#endif
+#if !defined(SQLITE_OMIT_UTF16)
+ {/* zName:     */ "encoding",
+  /* ePragTyp:  */ PragTyp_ENCODING,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+ {/* zName:     */ "foreign_key_check",
+  /* ePragTyp:  */ PragTyp_FOREIGN_KEY_CHECK,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 43, 4,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FOREIGN_KEY)
+ {/* zName:     */ "foreign_key_list",
+  /* ePragTyp:  */ PragTyp_FOREIGN_KEY_LIST,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 0, 8,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
+ {/* zName:     */ "foreign_keys",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ForeignKeys },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "freelist_count",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_ReadOnly|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_FREE_PAGE_COUNT },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "full_column_names",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_FullColNames },
+ {/* zName:     */ "fullfsync",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_FullFSync },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+#if !defined(SQLITE_OMIT_INTROSPECTION_PRAGMAS)
+ {/* zName:     */ "function_list",
+  /* ePragTyp:  */ PragTyp_FUNCTION_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 15, 6,
+  /* iArg:      */ 0 },
+#endif
+#endif
+ {/* zName:     */ "hard_heap_limit",
+  /* ePragTyp:  */ PragTyp_HARD_HEAP_LIMIT,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if !defined(SQLITE_OMIT_CHECK)
+ {/* zName:     */ "ignore_check_constraints",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_IgnoreChecks },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_AUTOVACUUM)
+ {/* zName:     */ "incremental_vacuum",
+  /* ePragTyp:  */ PragTyp_INCREMENTAL_VACUUM,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_NoColumns,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+ {/* zName:     */ "index_info",
+  /* ePragTyp:  */ PragTyp_INDEX_INFO,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 27, 3,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "index_list",
+  /* ePragTyp:  */ PragTyp_INDEX_LIST,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 33, 5,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "index_xinfo",
+  /* ePragTyp:  */ PragTyp_INDEX_INFO,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 27, 6,
+  /* iArg:      */ 1 },
+#endif
+#if !defined(SQLITE_OMIT_INTEGRITY_CHECK)
+ {/* zName:     */ "integrity_check",
+  /* ePragTyp:  */ PragTyp_INTEGRITY_CHECK,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "journal_mode",
+  /* ePragTyp:  */ PragTyp_JOURNAL_MODE,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "journal_size_limit",
+  /* ePragTyp:  */ PragTyp_JOURNAL_SIZE_LIMIT,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "legacy_alter_table",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_LegacyAlter },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && SQLITE_ENABLE_LOCKING_STYLE
+ {/* zName:     */ "lock_proxy_file",
+  /* ePragTyp:  */ PragTyp_LOCK_PROXY_FILE,
+  /* ePragFlg:  */ PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+ {/* zName:     */ "lock_status",
+  /* ePragTyp:  */ PragTyp_LOCK_STATUS,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 53, 2,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "locking_mode",
+  /* ePragTyp:  */ PragTyp_LOCKING_MODE,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "max_page_count",
+  /* ePragTyp:  */ PragTyp_PAGE_COUNT,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "mmap_size",
+  /* ePragTyp:  */ PragTyp_MMAP_SIZE,
+  /* ePragFlg:  */ 0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+#if !defined(SQLITE_OMIT_VIRTUALTABLE)
+#if !defined(SQLITE_OMIT_INTROSPECTION_PRAGMAS)
+ {/* zName:     */ "module_list",
+  /* ePragTyp:  */ PragTyp_MODULE_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 9, 1,
+  /* iArg:      */ 0 },
+#endif
+#endif
+#endif
+ {/* zName:     */ "optimize",
+  /* ePragTyp:  */ PragTyp_OPTIMIZE,
+  /* ePragFlg:  */ PragFlg_Result1|PragFlg_NeedSchema,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "page_count",
+  /* ePragTyp:  */ PragTyp_PAGE_COUNT,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "page_size",
+  /* ePragTyp:  */ PragTyp_PAGE_SIZE,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if defined(SQLITE_DEBUG)
+ {/* zName:     */ "parser_trace",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ParserTrace },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_INTROSPECTION_PRAGMAS)
+ {/* zName:     */ "pragma_list",
+  /* ePragTyp:  */ PragTyp_PRAGMA_LIST,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 9, 1,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "query_only",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_QueryOnly },
+#endif
+#if !defined(SQLITE_OMIT_INTEGRITY_CHECK)
+ {/* zName:     */ "quick_check",
+  /* ePragTyp:  */ PragTyp_INTEGRITY_CHECK,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "read_uncommitted",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ReadUncommit },
+ {/* zName:     */ "recursive_triggers",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_RecTriggers },
+ {/* zName:     */ "reverse_unordered_selects",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ReverseOrder },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "schema_version",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_NoColumns1|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_SCHEMA_VERSION },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "secure_delete",
+  /* ePragTyp:  */ PragTyp_SECURE_DELETE,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "short_column_names",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_ShortColNames },
+#endif
+ {/* zName:     */ "shrink_memory",
+  /* ePragTyp:  */ PragTyp_SHRINK_MEMORY,
+  /* ePragFlg:  */ PragFlg_NoColumns,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "soft_heap_limit",
+  /* ePragTyp:  */ PragTyp_SOFT_HEAP_LIMIT,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if defined(SQLITE_DEBUG)
+ {/* zName:     */ "sql_trace",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_SqlTrace },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS) && defined(SQLITE_DEBUG)
+ {/* zName:     */ "stats",
+  /* ePragTyp:  */ PragTyp_STATS,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq,
+  /* ColNames:  */ 38, 5,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "synchronous",
+  /* ePragTyp:  */ PragTyp_SYNCHRONOUS,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result0|PragFlg_SchemaReq|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_PRAGMAS)
+ {/* zName:     */ "table_info",
+  /* ePragTyp:  */ PragTyp_TABLE_INFO,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 8, 6,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "table_list",
+  /* ePragTyp:  */ PragTyp_TABLE_LIST,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1,
+  /* ColNames:  */ 21, 6,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "table_xinfo",
+  /* ePragTyp:  */ PragTyp_TABLE_INFO,
+  /* ePragFlg:  */ PragFlg_NeedSchema|PragFlg_Result1|PragFlg_SchemaOpt,
+  /* ColNames:  */ 8, 7,
+  /* iArg:      */ 1 },
+#endif
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+ {/* zName:     */ "temp_store",
+  /* ePragTyp:  */ PragTyp_TEMP_STORE,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "temp_store_directory",
+  /* ePragTyp:  */ PragTyp_TEMP_STORE_DIRECTORY,
+  /* ePragFlg:  */ PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#endif
+ {/* zName:     */ "threads",
+  /* ePragTyp:  */ PragTyp_THREADS,
+  /* ePragFlg:  */ PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "trusted_schema",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_TrustedSchema },
+#endif
+#if !defined(SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS)
+ {/* zName:     */ "user_version",
+  /* ePragTyp:  */ PragTyp_HEADER_VALUE,
+  /* ePragFlg:  */ PragFlg_NoColumns1|PragFlg_Result0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ BTREE_USER_VERSION },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if defined(SQLITE_DEBUG)
+ {/* zName:     */ "vdbe_addoptrace",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_VdbeAddopTrace },
+ {/* zName:     */ "vdbe_debug",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_SqlTrace|SQLITE_VdbeListing|SQLITE_VdbeTrace },
+ {/* zName:     */ "vdbe_eqp",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_VdbeEQP },
+ {/* zName:     */ "vdbe_listing",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_VdbeListing },
+ {/* zName:     */ "vdbe_trace",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_VdbeTrace },
+#endif
+#endif
+#if !defined(SQLITE_OMIT_WAL)
+ {/* zName:     */ "wal_autocheckpoint",
+  /* ePragTyp:  */ PragTyp_WAL_AUTOCHECKPOINT,
+  /* ePragFlg:  */ 0,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+ {/* zName:     */ "wal_checkpoint",
+  /* ePragTyp:  */ PragTyp_WAL_CHECKPOINT,
+  /* ePragFlg:  */ PragFlg_NeedSchema,
+  /* ColNames:  */ 47, 3,
+  /* iArg:      */ 0 },
+#endif
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+ {/* zName:     */ "writable_schema",
+  /* ePragTyp:  */ PragTyp_FLAG,
+  /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ SQLITE_WriteSchema|SQLITE_NoSchemaError },
+#endif
+};
+/* Number of pragmas: 68 on by default, 78 total. */
+
+/************** End of pragma.h **********************************************/
+/************** Continuing where we left off in pragma.c *********************/
+
+/*
+** When the 0x10 bit of PRAGMA optimize is set, any ANALYZE commands
+** will be run with an analysis_limit set to the lessor of the value of
+** the following macro or to the actual analysis_limit if it is non-zero,
+** in order to prevent PRAGMA optimize from running for too long.
+**
+** The value of 2000 is chosen emperically so that the worst-case run-time
+** for PRAGMA optimize does not exceed 100 milliseconds against a variety
+** of test databases on a RaspberryPI-4 compiled using -Os and without
+** -DSQLITE_DEBUG.  Of course, your mileage may vary.  For the purpose of
+** this paragraph, "worst-case" means that ANALYZE ends up being
+** run on every table in the database.  The worst case typically only
+** happens if PRAGMA optimize is run on a database file for which ANALYZE
+** has not been previously run and the 0x10000 flag is included so that
+** all tables are analyzed.  The usual case for PRAGMA optimize is that
+** no ANALYZE commands will be run at all, or if any ANALYZE happens it
+** will be against a single table, so that expected timing for PRAGMA
+** optimize on a PI-4 is more like 1 millisecond or less with the 0x10000
+** flag or less than 100 microseconds without the 0x10000 flag.
+**
+** An analysis limit of 2000 is almost always sufficient for the query
+** planner to fully characterize an index.  The additional accuracy from
+** a larger analysis is not usually helpful.
+*/
+#ifndef SQLITE_DEFAULT_OPTIMIZE_LIMIT
+# define SQLITE_DEFAULT_OPTIMIZE_LIMIT 2000
+#endif
+
+/*
+** Interpret the given string as a safety level.  Return 0 for OFF,
+** 1 for ON or NORMAL, 2 for FULL, and 3 for EXTRA.  Return 1 for an empty or
+** unrecognized string argument.  The FULL and EXTRA option is disallowed
+** if the omitFull parameter it 1.
+**
+** Note that the values returned are one less that the values that
+** should be passed into sqlite3BtreeSetSafetyLevel().  The is done
+** to support legacy SQL code.  The safety level used to be boolean
+** and older scripts may have used numbers 0 for OFF and 1 for ON.
+*/
+static u8 getSafetyLevel(const char *z, int omitFull, u8 dflt){
+                             /* 123456789 123456789 123 */
+  static const char zText[] = "onoffalseyestruextrafull";
+  static const u8 iOffset[] = {0, 1, 2,  4,    9,  12,  15,   20};
+  static const u8 iLength[] = {2, 2, 3,  5,    3,   4,   5,    4};
+  static const u8 iValue[] =  {1, 0, 0,  0,    1,   1,   3,    2};
+                            /* on no off false yes true extra full */
+  int i, n;
+  if( sqlite3Isdigit(*z) ){
+    return (u8)sqlite3Atoi(z);
+  }
+  n = sqlite3Strlen30(z);
+  for(i=0; i<ArraySize(iLength); i++){
+    if( iLength[i]==n && sqlite3StrNICmp(&zText[iOffset[i]],z,n)==0
+     && (!omitFull || iValue[i]<=1)
+    ){
+      return iValue[i];
+    }
+  }
+  return dflt;
+}
+
+/*
+** Interpret the given string as a boolean value.
+*/
+SQLITE_PRIVATE u8 sqlite3GetBoolean(const char *z, u8 dflt){
+  return getSafetyLevel(z,1,dflt)!=0;
+}
+
+/* The sqlite3GetBoolean() function is used by other modules but the
+** remainder of this file is specific to PRAGMA processing.  So omit
+** the rest of the file if PRAGMAs are omitted from the build.
+*/
+#if !defined(SQLITE_OMIT_PRAGMA)
+
+/*
+** Interpret the given string as a locking mode value.
+*/
+static int getLockingMode(const char *z){
+  if( z ){
+    if( 0==sqlite3StrICmp(z, "exclusive") ) return PAGER_LOCKINGMODE_EXCLUSIVE;
+    if( 0==sqlite3StrICmp(z, "normal") ) return PAGER_LOCKINGMODE_NORMAL;
+  }
+  return PAGER_LOCKINGMODE_QUERY;
+}
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+/*
+** Interpret the given string as an auto-vacuum mode value.
+**
+** The following strings, "none", "full" and "incremental" are
+** acceptable, as are their numeric equivalents: 0, 1 and 2 respectively.
+*/
+static int getAutoVacuum(const char *z){
+  int i;
+  if( 0==sqlite3StrICmp(z, "none") ) return BTREE_AUTOVACUUM_NONE;
+  if( 0==sqlite3StrICmp(z, "full") ) return BTREE_AUTOVACUUM_FULL;
+  if( 0==sqlite3StrICmp(z, "incremental") ) return BTREE_AUTOVACUUM_INCR;
+  i = sqlite3Atoi(z);
+  return (u8)((i>=0&&i<=2)?i:0);
+}
+#endif /* ifndef SQLITE_OMIT_AUTOVACUUM */
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+/*
+** Interpret the given string as a temp db location. Return 1 for file
+** backed temporary databases, 2 for the Red-Black tree in memory database
+** and 0 to use the compile-time default.
+*/
+static int getTempStore(const char *z){
+  if( z[0]>='0' && z[0]<='2' ){
+    return z[0] - '0';
+  }else if( sqlite3StrICmp(z, "file")==0 ){
+    return 1;
+  }else if( sqlite3StrICmp(z, "memory")==0 ){
+    return 2;
+  }else{
+    return 0;
+  }
+}
+#endif /* SQLITE_PAGER_PRAGMAS */
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+/*
+** Invalidate temp storage, either when the temp storage is changed
+** from default, or when 'file' and the temp_store_directory has changed
+*/
+static int invalidateTempStorage(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  if( db->aDb[1].pBt!=0 ){
+    if( !db->autoCommit
+     || sqlite3BtreeTxnState(db->aDb[1].pBt)!=SQLITE_TXN_NONE
+    ){
+      sqlite3ErrorMsg(pParse, "temporary storage cannot be changed "
+        "from within a transaction");
+      return SQLITE_ERROR;
+    }
+    sqlite3BtreeClose(db->aDb[1].pBt);
+    db->aDb[1].pBt = 0;
+    sqlite3ResetAllSchemasOfConnection(db);
+  }
+  return SQLITE_OK;
+}
+#endif /* SQLITE_PAGER_PRAGMAS */
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+/*
+** If the TEMP database is open, close it and mark the database schema
+** as needing reloading.  This must be done when using the SQLITE_TEMP_STORE
+** or DEFAULT_TEMP_STORE pragmas.
+*/
+static int changeTempStorage(Parse *pParse, const char *zStorageType){
+  int ts = getTempStore(zStorageType);
+  sqlite3 *db = pParse->db;
+  if( db->temp_store==ts ) return SQLITE_OK;
+  if( invalidateTempStorage( pParse ) != SQLITE_OK ){
+    return SQLITE_ERROR;
+  }
+  db->temp_store = (u8)ts;
+  return SQLITE_OK;
+}
+#endif /* SQLITE_PAGER_PRAGMAS */
+
+/*
+** Set result column names for a pragma.
+*/
+static void setPragmaResultColumnNames(
+  Vdbe *v,                     /* The query under construction */
+  const PragmaName *pPragma    /* The pragma */
+){
+  u8 n = pPragma->nPragCName;
+  sqlite3VdbeSetNumCols(v, n==0 ? 1 : n);
+  if( n==0 ){
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, pPragma->zName, SQLITE_STATIC);
+  }else{
+    int i, j;
+    for(i=0, j=pPragma->iPragCName; i<n; i++, j++){
+      sqlite3VdbeSetColName(v, i, COLNAME_NAME, pragCName[j], SQLITE_STATIC);
+    }
+  }
+}
+
+/*
+** Generate code to return a single integer value.
+*/
+static void returnSingleInt(Vdbe *v, i64 value){
+  sqlite3VdbeAddOp4Dup8(v, OP_Int64, 0, 1, 0, (const u8*)&value, P4_INT64);
+  sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+}
+
+/*
+** Generate code to return a single text value.
+*/
+static void returnSingleText(
+  Vdbe *v,                /* Prepared statement under construction */
+  const char *zValue      /* Value to be returned */
+){
+  if( zValue ){
+    sqlite3VdbeLoadString(v, 1, (const char*)zValue);
+    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+  }
+}
+
+
+/*
+** Set the safety_level and pager flags for pager iDb.  Or if iDb<0
+** set these values for all pagers.
+*/
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+static void setAllPagerFlags(sqlite3 *db){
+  if( db->autoCommit ){
+    Db *pDb = db->aDb;
+    int n = db->nDb;
+    assert( SQLITE_FullFSync==PAGER_FULLFSYNC );
+    assert( SQLITE_CkptFullFSync==PAGER_CKPT_FULLFSYNC );
+    assert( SQLITE_CacheSpill==PAGER_CACHESPILL );
+    assert( (PAGER_FULLFSYNC | PAGER_CKPT_FULLFSYNC | PAGER_CACHESPILL)
+             ==  PAGER_FLAGS_MASK );
+    assert( (pDb->safety_level & PAGER_SYNCHRONOUS_MASK)==pDb->safety_level );
+    while( (n--) > 0 ){
+      if( pDb->pBt ){
+        sqlite3BtreeSetPagerFlags(pDb->pBt,
+                 pDb->safety_level | (db->flags & PAGER_FLAGS_MASK) );
+      }
+      pDb++;
+    }
+  }
+}
+#else
+# define setAllPagerFlags(X)  /* no-op */
+#endif
+
+
+/*
+** Return a human-readable name for a constraint resolution action.
+*/
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+static const char *actionName(u8 action){
+  const char *zName;
+  switch( action ){
+    case OE_SetNull:  zName = "SET NULL";        break;
+    case OE_SetDflt:  zName = "SET DEFAULT";     break;
+    case OE_Cascade:  zName = "CASCADE";         break;
+    case OE_Restrict: zName = "RESTRICT";        break;
+    default:          zName = "NO ACTION";
+                      assert( action==OE_None ); break;
+  }
+  return zName;
+}
+#endif
+
+
+/*
+** Parameter eMode must be one of the PAGER_JOURNALMODE_XXX constants
+** defined in pager.h. This function returns the associated lowercase
+** journal-mode name.
+*/
+SQLITE_PRIVATE const char *sqlite3JournalModename(int eMode){
+  static char * const azModeName[] = {
+    "delete", "persist", "off", "truncate", "memory"
+#ifndef SQLITE_OMIT_WAL
+     , "wal"
+#endif
+  };
+  assert( PAGER_JOURNALMODE_DELETE==0 );
+  assert( PAGER_JOURNALMODE_PERSIST==1 );
+  assert( PAGER_JOURNALMODE_OFF==2 );
+  assert( PAGER_JOURNALMODE_TRUNCATE==3 );
+  assert( PAGER_JOURNALMODE_MEMORY==4 );
+  assert( PAGER_JOURNALMODE_WAL==5 );
+  assert( eMode>=0 && eMode<=ArraySize(azModeName) );
+
+  if( eMode==ArraySize(azModeName) ) return 0;
+  return azModeName[eMode];
+}
+
+/*
+** Locate a pragma in the aPragmaName[] array.
+*/
+static const PragmaName *pragmaLocate(const char *zName){
+  int upr, lwr, mid = 0, rc;
+  lwr = 0;
+  upr = ArraySize(aPragmaName)-1;
+  while( lwr<=upr ){
+    mid = (lwr+upr)/2;
+    rc = sqlite3_stricmp(zName, aPragmaName[mid].zName);
+    if( rc==0 ) break;
+    if( rc<0 ){
+      upr = mid - 1;
+    }else{
+      lwr = mid + 1;
+    }
+  }
+  return lwr>upr ? 0 : &aPragmaName[mid];
+}
+
+/*
+** Create zero or more entries in the output for the SQL functions
+** defined by FuncDef p.
+*/
+static void pragmaFunclistLine(
+  Vdbe *v,               /* The prepared statement being created */
+  FuncDef *p,            /* A particular function definition */
+  int isBuiltin,         /* True if this is a built-in function */
+  int showInternFuncs    /* True if showing internal functions */
+){
+  u32 mask =
+      SQLITE_DETERMINISTIC |
+      SQLITE_DIRECTONLY |
+      SQLITE_SUBTYPE |
+      SQLITE_INNOCUOUS |
+      SQLITE_FUNC_INTERNAL
+  ;
+  if( showInternFuncs ) mask = 0xffffffff;
+  for(; p; p=p->pNext){
+    const char *zType;
+    static const char *azEnc[] = { 0, "utf8", "utf16le", "utf16be" };
+
+    assert( SQLITE_FUNC_ENCMASK==0x3 );
+    assert( strcmp(azEnc[SQLITE_UTF8],"utf8")==0 );
+    assert( strcmp(azEnc[SQLITE_UTF16LE],"utf16le")==0 );
+    assert( strcmp(azEnc[SQLITE_UTF16BE],"utf16be")==0 );
+
+    if( p->xSFunc==0 ) continue;
+    if( (p->funcFlags & SQLITE_FUNC_INTERNAL)!=0
+     && showInternFuncs==0
+    ){
+      continue;
+    }
+    if( p->xValue!=0 ){
+      zType = "w";
+    }else if( p->xFinalize!=0 ){
+      zType = "a";
+    }else{
+      zType = "s";
+    }
+    sqlite3VdbeMultiLoad(v, 1, "sissii",
+       p->zName, isBuiltin,
+       zType, azEnc[p->funcFlags&SQLITE_FUNC_ENCMASK],
+       p->nArg,
+       (p->funcFlags & mask) ^ SQLITE_INNOCUOUS
+    );
+  }
+}
+
+
+/*
+** Helper subroutine for PRAGMA integrity_check:
+**
+** Generate code to output a single-column result row with a value of the
+** string held in register 3.  Decrement the result count in register 1
+** and halt if the maximum number of result rows have been issued.
+*/
+static int integrityCheckResultRow(Vdbe *v){
+  int addr;
+  sqlite3VdbeAddOp2(v, OP_ResultRow, 3, 1);
+  addr = sqlite3VdbeAddOp3(v, OP_IfPos, 1, sqlite3VdbeCurrentAddr(v)+2, 1);
+  VdbeCoverage(v);
+  sqlite3VdbeAddOp0(v, OP_Halt);
+  return addr;
+}
+
+/*
+** Process a pragma statement.
+**
+** Pragmas are of this form:
+**
+**      PRAGMA [schema.]id [= value]
+**
+** The identifier might also be a string.  The value is a string, and
+** identifier, or a number.  If minusFlag is true, then the value is
+** a number that was preceded by a minus sign.
+**
+** If the left side is "database.id" then pId1 is the database name
+** and pId2 is the id.  If the left side is just "id" then pId1 is the
+** id and pId2 is any empty string.
+*/
+SQLITE_PRIVATE void sqlite3Pragma(
+  Parse *pParse,
+  Token *pId1,        /* First part of [schema.]id field */
+  Token *pId2,        /* Second part of [schema.]id field, or NULL */
+  Token *pValue,      /* Token for <value>, or NULL */
+  int minusFlag       /* True if a '-' sign preceded <value> */
+){
+  char *zLeft = 0;       /* Nul-terminated UTF-8 string <id> */
+  char *zRight = 0;      /* Nul-terminated UTF-8 string <value>, or NULL */
+  const char *zDb = 0;   /* The database name */
+  Token *pId;            /* Pointer to <id> token */
+  char *aFcntl[4];       /* Argument to SQLITE_FCNTL_PRAGMA */
+  int iDb;               /* Database index for <database> */
+  int rc;                      /* return value form SQLITE_FCNTL_PRAGMA */
+  sqlite3 *db = pParse->db;    /* The database connection */
+  Db *pDb;                     /* The specific database being pragmaed */
+  Vdbe *v = sqlite3GetVdbe(pParse);  /* Prepared statement */
+  const PragmaName *pPragma;   /* The pragma */
+
+  if( v==0 ) return;
+  sqlite3VdbeRunOnlyOnce(v);
+  pParse->nMem = 2;
+
+  /* Interpret the [schema.] part of the pragma statement. iDb is the
+  ** index of the database this pragma is being applied to in db.aDb[]. */
+  iDb = sqlite3TwoPartName(pParse, pId1, pId2, &pId);
+  if( iDb<0 ) return;
+  pDb = &db->aDb[iDb];
+
+  /* If the temp database has been explicitly named as part of the
+  ** pragma, make sure it is open.
+  */
+  if( iDb==1 && sqlite3OpenTempDatabase(pParse) ){
+    return;
+  }
+
+  zLeft = sqlite3NameFromToken(db, pId);
+  if( !zLeft ) return;
+  if( minusFlag ){
+    zRight = sqlite3MPrintf(db, "-%T", pValue);
+  }else{
+    zRight = sqlite3NameFromToken(db, pValue);
+  }
+
+  assert( pId2 );
+  zDb = pId2->n>0 ? pDb->zDbSName : 0;
+  if( sqlite3AuthCheck(pParse, SQLITE_PRAGMA, zLeft, zRight, zDb) ){
+    goto pragma_out;
+  }
+
+  /* Send an SQLITE_FCNTL_PRAGMA file-control to the underlying VFS
+  ** connection.  If it returns SQLITE_OK, then assume that the VFS
+  ** handled the pragma and generate a no-op prepared statement.
+  **
+  ** IMPLEMENTATION-OF: R-12238-55120 Whenever a PRAGMA statement is parsed,
+  ** an SQLITE_FCNTL_PRAGMA file control is sent to the open sqlite3_file
+  ** object corresponding to the database file to which the pragma
+  ** statement refers.
+  **
+  ** IMPLEMENTATION-OF: R-29875-31678 The argument to the SQLITE_FCNTL_PRAGMA
+  ** file control is an array of pointers to strings (char**) in which the
+  ** second element of the array is the name of the pragma and the third
+  ** element is the argument to the pragma or NULL if the pragma has no
+  ** argument.
+  */
+  aFcntl[0] = 0;
+  aFcntl[1] = zLeft;
+  aFcntl[2] = zRight;
+  aFcntl[3] = 0;
+  db->busyHandler.nBusy = 0;
+  rc = sqlite3_file_control(db, zDb, SQLITE_FCNTL_PRAGMA, (void*)aFcntl);
+  if( rc==SQLITE_OK ){
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, aFcntl[0], SQLITE_TRANSIENT);
+    returnSingleText(v, aFcntl[0]);
+    sqlite3_free(aFcntl[0]);
+    goto pragma_out;
+  }
+  if( rc!=SQLITE_NOTFOUND ){
+    if( aFcntl[0] ){
+      sqlite3ErrorMsg(pParse, "%s", aFcntl[0]);
+      sqlite3_free(aFcntl[0]);
+    }
+    pParse->nErr++;
+    pParse->rc = rc;
+    goto pragma_out;
+  }
+
+  /* Locate the pragma in the lookup table */
+  pPragma = pragmaLocate(zLeft);
+  if( pPragma==0 ){
+    /* IMP: R-43042-22504 No error messages are generated if an
+    ** unknown pragma is issued. */
+    goto pragma_out;
+  }
+
+  /* Make sure the database schema is loaded if the pragma requires that */
+  if( (pPragma->mPragFlg & PragFlg_NeedSchema)!=0 ){
+    if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+  }
+
+  /* Register the result column names for pragmas that return results */
+  if( (pPragma->mPragFlg & PragFlg_NoColumns)==0
+   && ((pPragma->mPragFlg & PragFlg_NoColumns1)==0 || zRight==0)
+  ){
+    setPragmaResultColumnNames(v, pPragma);
+  }
+
+  /* Jump to the appropriate pragma handler */
+  switch( pPragma->ePragTyp ){
+
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS) && !defined(SQLITE_OMIT_DEPRECATED)
+  /*
+  **  PRAGMA [schema.]default_cache_size
+  **  PRAGMA [schema.]default_cache_size=N
+  **
+  ** The first form reports the current persistent setting for the
+  ** page cache size.  The value returned is the maximum number of
+  ** pages in the page cache.  The second form sets both the current
+  ** page cache size value and the persistent page cache size value
+  ** stored in the database file.
+  **
+  ** Older versions of SQLite would set the default cache size to a
+  ** negative number to indicate synchronous=OFF.  These days, synchronous
+  ** is always on by default regardless of the sign of the default cache
+  ** size.  But continue to take the absolute value of the default cache
+  ** size of historical compatibility.
+  */
+  case PragTyp_DEFAULT_CACHE_SIZE: {
+    static const int iLn = VDBE_OFFSET_LINENO(2);
+    static const VdbeOpList getCacheSize[] = {
+      { OP_Transaction, 0, 0,        0},                         /* 0 */
+      { OP_ReadCookie,  0, 1,        BTREE_DEFAULT_CACHE_SIZE},  /* 1 */
+      { OP_IfPos,       1, 8,        0},
+      { OP_Integer,     0, 2,        0},
+      { OP_Subtract,    1, 2,        1},
+      { OP_IfPos,       1, 8,        0},
+      { OP_Integer,     0, 1,        0},                         /* 6 */
+      { OP_Noop,        0, 0,        0},
+      { OP_ResultRow,   1, 1,        0},
+    };
+    VdbeOp *aOp;
+    sqlite3VdbeUsesBtree(v, iDb);
+    if( !zRight ){
+      pParse->nMem += 2;
+      sqlite3VdbeVerifyNoMallocRequired(v, ArraySize(getCacheSize));
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(getCacheSize), getCacheSize, iLn);
+      if( ONLY_IF_REALLOC_STRESS(aOp==0) ) break;
+      aOp[0].p1 = iDb;
+      aOp[1].p1 = iDb;
+      aOp[6].p1 = SQLITE_DEFAULT_CACHE_SIZE;
+    }else{
+      int size = sqlite3AbsInt32(sqlite3Atoi(zRight));
+      sqlite3BeginWriteOperation(pParse, 0, iDb);
+      sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_DEFAULT_CACHE_SIZE, size);
+      assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+      pDb->pSchema->cache_size = size;
+      sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
+    }
+    break;
+  }
+#endif /* !SQLITE_OMIT_PAGER_PRAGMAS && !SQLITE_OMIT_DEPRECATED */
+
+#if !defined(SQLITE_OMIT_PAGER_PRAGMAS)
+  /*
+  **  PRAGMA [schema.]page_size
+  **  PRAGMA [schema.]page_size=N
+  **
+  ** The first form reports the current setting for the
+  ** database page size in bytes.  The second form sets the
+  ** database page size value.  The value can only be set if
+  ** the database has not yet been created.
+  */
+  case PragTyp_PAGE_SIZE: {
+    Btree *pBt = pDb->pBt;
+    assert( pBt!=0 );
+    if( !zRight ){
+      int size = ALWAYS(pBt) ? sqlite3BtreeGetPageSize(pBt) : 0;
+      returnSingleInt(v, size);
+    }else{
+      /* Malloc may fail when setting the page-size, as there is an internal
+      ** buffer that the pager module resizes using sqlite3_realloc().
+      */
+      db->nextPagesize = sqlite3Atoi(zRight);
+      if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize,0,0) ){
+        sqlite3OomFault(db);
+      }
+    }
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]secure_delete
+  **  PRAGMA [schema.]secure_delete=ON/OFF/FAST
+  **
+  ** The first form reports the current setting for the
+  ** secure_delete flag.  The second form changes the secure_delete
+  ** flag setting and reports the new value.
+  */
+  case PragTyp_SECURE_DELETE: {
+    Btree *pBt = pDb->pBt;
+    int b = -1;
+    assert( pBt!=0 );
+    if( zRight ){
+      if( sqlite3_stricmp(zRight, "fast")==0 ){
+        b = 2;
+      }else{
+        b = sqlite3GetBoolean(zRight, 0);
+      }
+    }
+    if( pId2->n==0 && b>=0 ){
+      int ii;
+      for(ii=0; ii<db->nDb; ii++){
+        sqlite3BtreeSecureDelete(db->aDb[ii].pBt, b);
+      }
+    }
+    b = sqlite3BtreeSecureDelete(pBt, b);
+    returnSingleInt(v, b);
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]max_page_count
+  **  PRAGMA [schema.]max_page_count=N
+  **
+  ** The first form reports the current setting for the
+  ** maximum number of pages in the database file.  The
+  ** second form attempts to change this setting.  Both
+  ** forms return the current setting.
+  **
+  ** The absolute value of N is used.  This is undocumented and might
+  ** change.  The only purpose is to provide an easy way to test
+  ** the sqlite3AbsInt32() function.
+  **
+  **  PRAGMA [schema.]page_count
+  **
+  ** Return the number of pages in the specified database.
+  */
+  case PragTyp_PAGE_COUNT: {
+    int iReg;
+    i64 x = 0;
+    sqlite3CodeVerifySchema(pParse, iDb);
+    iReg = ++pParse->nMem;
+    if( sqlite3Tolower(zLeft[0])=='p' ){
+      sqlite3VdbeAddOp2(v, OP_Pagecount, iDb, iReg);
+    }else{
+      if( zRight && sqlite3DecOrHexToI64(zRight,&x)==0 ){
+        if( x<0 ) x = 0;
+        else if( x>0xfffffffe ) x = 0xfffffffe;
+      }else{
+        x = 0;
+      }
+      sqlite3VdbeAddOp3(v, OP_MaxPgcnt, iDb, iReg, (int)x);
+    }
+    sqlite3VdbeAddOp2(v, OP_ResultRow, iReg, 1);
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]locking_mode
+  **  PRAGMA [schema.]locking_mode = (normal|exclusive)
+  */
+  case PragTyp_LOCKING_MODE: {
+    const char *zRet = "normal";
+    int eMode = getLockingMode(zRight);
+
+    if( pId2->n==0 && eMode==PAGER_LOCKINGMODE_QUERY ){
+      /* Simple "PRAGMA locking_mode;" statement. This is a query for
+      ** the current default locking mode (which may be different to
+      ** the locking-mode of the main database).
+      */
+      eMode = db->dfltLockMode;
+    }else{
+      Pager *pPager;
+      if( pId2->n==0 ){
+        /* This indicates that no database name was specified as part
+        ** of the PRAGMA command. In this case the locking-mode must be
+        ** set on all attached databases, as well as the main db file.
+        **
+        ** Also, the sqlite3.dfltLockMode variable is set so that
+        ** any subsequently attached databases also use the specified
+        ** locking mode.
+        */
+        int ii;
+        assert(pDb==&db->aDb[0]);
+        for(ii=2; ii<db->nDb; ii++){
+          pPager = sqlite3BtreePager(db->aDb[ii].pBt);
+          sqlite3PagerLockingMode(pPager, eMode);
+        }
+        db->dfltLockMode = (u8)eMode;
+      }
+      pPager = sqlite3BtreePager(pDb->pBt);
+      eMode = sqlite3PagerLockingMode(pPager, eMode);
+    }
+
+    assert( eMode==PAGER_LOCKINGMODE_NORMAL
+            || eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
+    if( eMode==PAGER_LOCKINGMODE_EXCLUSIVE ){
+      zRet = "exclusive";
+    }
+    returnSingleText(v, zRet);
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]journal_mode
+  **  PRAGMA [schema.]journal_mode =
+  **                      (delete|persist|off|truncate|memory|wal|off)
+  */
+  case PragTyp_JOURNAL_MODE: {
+    int eMode;        /* One of the PAGER_JOURNALMODE_XXX symbols */
+    int ii;           /* Loop counter */
+
+    if( zRight==0 ){
+      /* If there is no "=MODE" part of the pragma, do a query for the
+      ** current mode */
+      eMode = PAGER_JOURNALMODE_QUERY;
+    }else{
+      const char *zMode;
+      int n = sqlite3Strlen30(zRight);
+      for(eMode=0; (zMode = sqlite3JournalModename(eMode))!=0; eMode++){
+        if( sqlite3StrNICmp(zRight, zMode, n)==0 ) break;
+      }
+      if( !zMode ){
+        /* If the "=MODE" part does not match any known journal mode,
+        ** then do a query */
+        eMode = PAGER_JOURNALMODE_QUERY;
+      }
+      if( eMode==PAGER_JOURNALMODE_OFF && (db->flags & SQLITE_Defensive)!=0 ){
+        /* Do not allow journal-mode "OFF" in defensive since the database
+        ** can become corrupted using ordinary SQL when the journal is off */
+        eMode = PAGER_JOURNALMODE_QUERY;
+      }
+    }
+    if( eMode==PAGER_JOURNALMODE_QUERY && pId2->n==0 ){
+      /* Convert "PRAGMA journal_mode" into "PRAGMA main.journal_mode" */
+      iDb = 0;
+      pId2->n = 1;
+    }
+    for(ii=db->nDb-1; ii>=0; ii--){
+      if( db->aDb[ii].pBt && (ii==iDb || pId2->n==0) ){
+        sqlite3VdbeUsesBtree(v, ii);
+        sqlite3VdbeAddOp3(v, OP_JournalMode, ii, 1, eMode);
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]journal_size_limit
+  **  PRAGMA [schema.]journal_size_limit=N
+  **
+  ** Get or set the size limit on rollback journal files.
+  */
+  case PragTyp_JOURNAL_SIZE_LIMIT: {
+    Pager *pPager = sqlite3BtreePager(pDb->pBt);
+    i64 iLimit = -2;
+    if( zRight ){
+      sqlite3DecOrHexToI64(zRight, &iLimit);
+      if( iLimit<-1 ) iLimit = -1;
+    }
+    iLimit = sqlite3PagerJournalSizeLimit(pPager, iLimit);
+    returnSingleInt(v, iLimit);
+    break;
+  }
+
+#endif /* SQLITE_OMIT_PAGER_PRAGMAS */
+
+  /*
+  **  PRAGMA [schema.]auto_vacuum
+  **  PRAGMA [schema.]auto_vacuum=N
+  **
+  ** Get or set the value of the database 'auto-vacuum' parameter.
+  ** The value is one of:  0 NONE 1 FULL 2 INCREMENTAL
+  */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  case PragTyp_AUTO_VACUUM: {
+    Btree *pBt = pDb->pBt;
+    assert( pBt!=0 );
+    if( !zRight ){
+      returnSingleInt(v, sqlite3BtreeGetAutoVacuum(pBt));
+    }else{
+      int eAuto = getAutoVacuum(zRight);
+      assert( eAuto>=0 && eAuto<=2 );
+      db->nextAutovac = (u8)eAuto;
+      /* Call SetAutoVacuum() to set initialize the internal auto and
+      ** incr-vacuum flags. This is required in case this connection
+      ** creates the database file. It is important that it is created
+      ** as an auto-vacuum capable db.
+      */
+      rc = sqlite3BtreeSetAutoVacuum(pBt, eAuto);
+      if( rc==SQLITE_OK && (eAuto==1 || eAuto==2) ){
+        /* When setting the auto_vacuum mode to either "full" or
+        ** "incremental", write the value of meta[6] in the database
+        ** file. Before writing to meta[6], check that meta[3] indicates
+        ** that this really is an auto-vacuum capable database.
+        */
+        static const int iLn = VDBE_OFFSET_LINENO(2);
+        static const VdbeOpList setMeta6[] = {
+          { OP_Transaction,    0,         1,                 0},    /* 0 */
+          { OP_ReadCookie,     0,         1,         BTREE_LARGEST_ROOT_PAGE},
+          { OP_If,             1,         0,                 0},    /* 2 */
+          { OP_Halt,           SQLITE_OK, OE_Abort,          0},    /* 3 */
+          { OP_SetCookie,      0,         BTREE_INCR_VACUUM, 0},    /* 4 */
+        };
+        VdbeOp *aOp;
+        int iAddr = sqlite3VdbeCurrentAddr(v);
+        sqlite3VdbeVerifyNoMallocRequired(v, ArraySize(setMeta6));
+        aOp = sqlite3VdbeAddOpList(v, ArraySize(setMeta6), setMeta6, iLn);
+        if( ONLY_IF_REALLOC_STRESS(aOp==0) ) break;
+        aOp[0].p1 = iDb;
+        aOp[1].p1 = iDb;
+        aOp[2].p2 = iAddr+4;
+        aOp[4].p1 = iDb;
+        aOp[4].p3 = eAuto - 1;
+        sqlite3VdbeUsesBtree(v, iDb);
+      }
+    }
+    break;
+  }
+#endif
+
+  /*
+  **  PRAGMA [schema.]incremental_vacuum(N)
+  **
+  ** Do N steps of incremental vacuuming on a database.
+  */
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  case PragTyp_INCREMENTAL_VACUUM: {
+    int iLimit = 0, addr;
+    if( zRight==0 || !sqlite3GetInt32(zRight, &iLimit) || iLimit<=0 ){
+      iLimit = 0x7fffffff;
+    }
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    sqlite3VdbeAddOp2(v, OP_Integer, iLimit, 1);
+    addr = sqlite3VdbeAddOp1(v, OP_IncrVacuum, iDb); VdbeCoverage(v);
+    sqlite3VdbeAddOp1(v, OP_ResultRow, 1);
+    sqlite3VdbeAddOp2(v, OP_AddImm, 1, -1);
+    sqlite3VdbeAddOp2(v, OP_IfPos, 1, addr); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr);
+    break;
+  }
+#endif
+
+#ifndef SQLITE_OMIT_PAGER_PRAGMAS
+  /*
+  **  PRAGMA [schema.]cache_size
+  **  PRAGMA [schema.]cache_size=N
+  **
+  ** The first form reports the current local setting for the
+  ** page cache size. The second form sets the local
+  ** page cache size value.  If N is positive then that is the
+  ** number of pages in the cache.  If N is negative, then the
+  ** number of pages is adjusted so that the cache uses -N kibibytes
+  ** of memory.
+  */
+  case PragTyp_CACHE_SIZE: {
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( !zRight ){
+      returnSingleInt(v, pDb->pSchema->cache_size);
+    }else{
+      int size = sqlite3Atoi(zRight);
+      pDb->pSchema->cache_size = size;
+      sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
+    }
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]cache_spill
+  **  PRAGMA cache_spill=BOOLEAN
+  **  PRAGMA [schema.]cache_spill=N
+  **
+  ** The first form reports the current local setting for the
+  ** page cache spill size. The second form turns cache spill on
+  ** or off.  When turning cache spill on, the size is set to the
+  ** current cache_size.  The third form sets a spill size that
+  ** may be different form the cache size.
+  ** If N is positive then that is the
+  ** number of pages in the cache.  If N is negative, then the
+  ** number of pages is adjusted so that the cache uses -N kibibytes
+  ** of memory.
+  **
+  ** If the number of cache_spill pages is less then the number of
+  ** cache_size pages, no spilling occurs until the page count exceeds
+  ** the number of cache_size pages.
+  **
+  ** The cache_spill=BOOLEAN setting applies to all attached schemas,
+  ** not just the schema specified.
+  */
+  case PragTyp_CACHE_SPILL: {
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( !zRight ){
+      returnSingleInt(v,
+         (db->flags & SQLITE_CacheSpill)==0 ? 0 :
+            sqlite3BtreeSetSpillSize(pDb->pBt,0));
+    }else{
+      int size = 1;
+      if( sqlite3GetInt32(zRight, &size) ){
+        sqlite3BtreeSetSpillSize(pDb->pBt, size);
+      }
+      if( sqlite3GetBoolean(zRight, size!=0) ){
+        db->flags |= SQLITE_CacheSpill;
+      }else{
+        db->flags &= ~(u64)SQLITE_CacheSpill;
+      }
+      setAllPagerFlags(db);
+    }
+    break;
+  }
+
+  /*
+  **  PRAGMA [schema.]mmap_size(N)
+  **
+  ** Used to set mapping size limit. The mapping size limit is
+  ** used to limit the aggregate size of all memory mapped regions of the
+  ** database file. If this parameter is set to zero, then memory mapping
+  ** is not used at all.  If N is negative, then the default memory map
+  ** limit determined by sqlite3_config(SQLITE_CONFIG_MMAP_SIZE) is set.
+  ** The parameter N is measured in bytes.
+  **
+  ** This value is advisory.  The underlying VFS is free to memory map
+  ** as little or as much as it wants.  Except, if N is set to 0 then the
+  ** upper layers will never invoke the xFetch interfaces to the VFS.
+  */
+  case PragTyp_MMAP_SIZE: {
+    sqlite3_int64 sz;
+#if SQLITE_MAX_MMAP_SIZE>0
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( zRight ){
+      int ii;
+      sqlite3DecOrHexToI64(zRight, &sz);
+      if( sz<0 ) sz = sqlite3GlobalConfig.szMmap;
+      if( pId2->n==0 ) db->szMmap = sz;
+      for(ii=db->nDb-1; ii>=0; ii--){
+        if( db->aDb[ii].pBt && (ii==iDb || pId2->n==0) ){
+          sqlite3BtreeSetMmapLimit(db->aDb[ii].pBt, sz);
+        }
+      }
+    }
+    sz = -1;
+    rc = sqlite3_file_control(db, zDb, SQLITE_FCNTL_MMAP_SIZE, &sz);
+#else
+    sz = 0;
+    rc = SQLITE_OK;
+#endif
+    if( rc==SQLITE_OK ){
+      returnSingleInt(v, sz);
+    }else if( rc!=SQLITE_NOTFOUND ){
+      pParse->nErr++;
+      pParse->rc = rc;
+    }
+    break;
+  }
+
+  /*
+  **   PRAGMA temp_store
+  **   PRAGMA temp_store = "default"|"memory"|"file"
+  **
+  ** Return or set the local value of the temp_store flag.  Changing
+  ** the local value does not make changes to the disk file and the default
+  ** value will be restored the next time the database is opened.
+  **
+  ** Note that it is possible for the library compile-time options to
+  ** override this setting
+  */
+  case PragTyp_TEMP_STORE: {
+    if( !zRight ){
+      returnSingleInt(v, db->temp_store);
+    }else{
+      changeTempStorage(pParse, zRight);
+    }
+    break;
+  }
+
+  /*
+  **   PRAGMA temp_store_directory
+  **   PRAGMA temp_store_directory = ""|"directory_name"
+  **
+  ** Return or set the local value of the temp_store_directory flag.  Changing
+  ** the value sets a specific directory to be used for temporary files.
+  ** Setting to a null string reverts to the default temporary directory search.
+  ** If temporary directory is changed, then invalidateTempStorage.
+  **
+  */
+  case PragTyp_TEMP_STORE_DIRECTORY: {
+    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+    if( !zRight ){
+      returnSingleText(v, sqlite3_temp_directory);
+    }else{
+#ifndef SQLITE_OMIT_WSD
+      if( zRight[0] ){
+        int res;
+        rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
+        if( rc!=SQLITE_OK || res==0 ){
+          sqlite3ErrorMsg(pParse, "not a writable directory");
+          sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+          goto pragma_out;
+        }
+      }
+      if( SQLITE_TEMP_STORE==0
+       || (SQLITE_TEMP_STORE==1 && db->temp_store<=1)
+       || (SQLITE_TEMP_STORE==2 && db->temp_store==1)
+      ){
+        invalidateTempStorage(pParse);
+      }
+      sqlite3_free(sqlite3_temp_directory);
+      if( zRight[0] ){
+        sqlite3_temp_directory = sqlite3_mprintf("%s", zRight);
+      }else{
+        sqlite3_temp_directory = 0;
+      }
+#endif /* SQLITE_OMIT_WSD */
+    }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+    break;
+  }
+
+#if SQLITE_OS_WIN
+  /*
+  **   PRAGMA data_store_directory
+  **   PRAGMA data_store_directory = ""|"directory_name"
+  **
+  ** Return or set the local value of the data_store_directory flag.  Changing
+  ** the value sets a specific directory to be used for database files that
+  ** were specified with a relative pathname.  Setting to a null string reverts
+  ** to the default database directory, which for database files specified with
+  ** a relative path will probably be based on the current directory for the
+  ** process.  Database file specified with an absolute path are not impacted
+  ** by this setting, regardless of its value.
+  **
+  */
+  case PragTyp_DATA_STORE_DIRECTORY: {
+    sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+    if( !zRight ){
+      returnSingleText(v, sqlite3_data_directory);
+    }else{
+#ifndef SQLITE_OMIT_WSD
+      if( zRight[0] ){
+        int res;
+        rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
+        if( rc!=SQLITE_OK || res==0 ){
+          sqlite3ErrorMsg(pParse, "not a writable directory");
+          sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+          goto pragma_out;
+        }
+      }
+      sqlite3_free(sqlite3_data_directory);
+      if( zRight[0] ){
+        sqlite3_data_directory = sqlite3_mprintf("%s", zRight);
+      }else{
+        sqlite3_data_directory = 0;
+      }
+#endif /* SQLITE_OMIT_WSD */
+    }
+    sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_TEMPDIR));
+    break;
+  }
+#endif
+
+#if SQLITE_ENABLE_LOCKING_STYLE
+  /*
+  **   PRAGMA [schema.]lock_proxy_file
+  **   PRAGMA [schema.]lock_proxy_file = ":auto:"|"lock_file_path"
+  **
+  ** Return or set the value of the lock_proxy_file flag.  Changing
+  ** the value sets a specific file to be used for database access locks.
+  **
+  */
+  case PragTyp_LOCK_PROXY_FILE: {
+    if( !zRight ){
+      Pager *pPager = sqlite3BtreePager(pDb->pBt);
+      char *proxy_file_path = NULL;
+      sqlite3_file *pFile = sqlite3PagerFile(pPager);
+      sqlite3OsFileControlHint(pFile, SQLITE_GET_LOCKPROXYFILE,
+                           &proxy_file_path);
+      returnSingleText(v, proxy_file_path);
+    }else{
+      Pager *pPager = sqlite3BtreePager(pDb->pBt);
+      sqlite3_file *pFile = sqlite3PagerFile(pPager);
+      int res;
+      if( zRight[0] ){
+        res=sqlite3OsFileControl(pFile, SQLITE_SET_LOCKPROXYFILE,
+                                     zRight);
+      } else {
+        res=sqlite3OsFileControl(pFile, SQLITE_SET_LOCKPROXYFILE,
+                                     NULL);
+      }
+      if( res!=SQLITE_OK ){
+        sqlite3ErrorMsg(pParse, "failed to set lock proxy file");
+        goto pragma_out;
+      }
+    }
+    break;
+  }
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
+  /*
+  **   PRAGMA [schema.]synchronous
+  **   PRAGMA [schema.]synchronous=OFF|ON|NORMAL|FULL|EXTRA
+  **
+  ** Return or set the local value of the synchronous flag.  Changing
+  ** the local value does not make changes to the disk file and the
+  ** default value will be restored the next time the database is
+  ** opened.
+  */
+  case PragTyp_SYNCHRONOUS: {
+    if( !zRight ){
+      returnSingleInt(v, pDb->safety_level-1);
+    }else{
+      if( !db->autoCommit ){
+        sqlite3ErrorMsg(pParse,
+            "Safety level may not be changed inside a transaction");
+      }else if( iDb!=1 ){
+        int iLevel = (getSafetyLevel(zRight,0,1)+1) & PAGER_SYNCHRONOUS_MASK;
+        if( iLevel==0 ) iLevel = 1;
+        pDb->safety_level = iLevel;
+        pDb->bSyncSet = 1;
+        setAllPagerFlags(db);
+      }
+    }
+    break;
+  }
+#endif /* SQLITE_OMIT_PAGER_PRAGMAS */
+
+#ifndef SQLITE_OMIT_FLAG_PRAGMAS
+  case PragTyp_FLAG: {
+    if( zRight==0 ){
+      setPragmaResultColumnNames(v, pPragma);
+      returnSingleInt(v, (db->flags & pPragma->iArg)!=0 );
+    }else{
+      u64 mask = pPragma->iArg;    /* Mask of bits to set or clear. */
+      if( db->autoCommit==0 ){
+        /* Foreign key support may not be enabled or disabled while not
+        ** in auto-commit mode.  */
+        mask &= ~(SQLITE_ForeignKeys);
+      }
+
+      if( sqlite3GetBoolean(zRight, 0) ){
+        if( (mask & SQLITE_WriteSchema)==0
+         || (db->flags & SQLITE_Defensive)==0
+        ){
+          db->flags |= mask;
+        }
+      }else{
+        db->flags &= ~mask;
+        if( mask==SQLITE_DeferFKs ) db->nDeferredImmCons = 0;
+        if( (mask & SQLITE_WriteSchema)!=0
+         && sqlite3_stricmp(zRight, "reset")==0
+        ){
+          /* IMP: R-60817-01178 If the argument is "RESET" then schema
+          ** writing is disabled (as with "PRAGMA writable_schema=OFF") and,
+          ** in addition, the schema is reloaded. */
+          sqlite3ResetAllSchemasOfConnection(db);
+        }
+      }
+
+      /* Many of the flag-pragmas modify the code generated by the SQL
+      ** compiler (eg. count_changes). So add an opcode to expire all
+      ** compiled SQL statements after modifying a pragma value.
+      */
+      sqlite3VdbeAddOp0(v, OP_Expire);
+      setAllPagerFlags(db);
+    }
+    break;
+  }
+#endif /* SQLITE_OMIT_FLAG_PRAGMAS */
+
+#ifndef SQLITE_OMIT_SCHEMA_PRAGMAS
+  /*
+  **   PRAGMA table_info(<table>)
+  **
+  ** Return a single row for each column of the named table. The columns of
+  ** the returned data set are:
+  **
+  ** cid:        Column id (numbered from left to right, starting at 0)
+  ** name:       Column name
+  ** type:       Column declaration type.
+  ** notnull:    True if 'NOT NULL' is part of column declaration
+  ** dflt_value: The default value for the column, if any.
+  ** pk:         Non-zero for PK fields.
+  */
+  case PragTyp_TABLE_INFO: if( zRight ){
+    Table *pTab;
+    sqlite3CodeVerifyNamedSchema(pParse, zDb);
+    pTab = sqlite3LocateTable(pParse, LOCATE_NOERR, zRight, zDb);
+    if( pTab ){
+      int i, k;
+      int nHidden = 0;
+      Column *pCol;
+      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+      pParse->nMem = 7;
+      sqlite3ViewGetColumnNames(pParse, pTab);
+      for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
+        int isHidden = 0;
+        const Expr *pColExpr;
+        if( pCol->colFlags & COLFLAG_NOINSERT ){
+          if( pPragma->iArg==0 ){
+            nHidden++;
+            continue;
+          }
+          if( pCol->colFlags & COLFLAG_VIRTUAL ){
+            isHidden = 2;  /* GENERATED ALWAYS AS ... VIRTUAL */
+          }else if( pCol->colFlags & COLFLAG_STORED ){
+            isHidden = 3;  /* GENERATED ALWAYS AS ... STORED */
+          }else{ assert( pCol->colFlags & COLFLAG_HIDDEN );
+            isHidden = 1;  /* HIDDEN */
+          }
+        }
+        if( (pCol->colFlags & COLFLAG_PRIMKEY)==0 ){
+          k = 0;
+        }else if( pPk==0 ){
+          k = 1;
+        }else{
+          for(k=1; k<=pTab->nCol && pPk->aiColumn[k-1]!=i; k++){}
+        }
+        pColExpr = sqlite3ColumnExpr(pTab,pCol);
+        assert( pColExpr==0 || pColExpr->op==TK_SPAN || isHidden>=2 );
+        assert( pColExpr==0 || !ExprHasProperty(pColExpr, EP_IntValue)
+                  || isHidden>=2 );
+        sqlite3VdbeMultiLoad(v, 1, pPragma->iArg ? "issisii" : "issisi",
+               i-nHidden,
+               pCol->zCnName,
+               sqlite3ColumnType(pCol,""),
+               pCol->notNull ? 1 : 0,
+               (isHidden>=2 || pColExpr==0) ? 0 : pColExpr->u.zToken,
+               k,
+               isHidden);
+      }
+    }
+  }
+  break;
+
+  /*
+  **   PRAGMA table_list
+  **
+  ** Return a single row for each table, virtual table, or view in the
+  ** entire schema.
+  **
+  ** schema:     Name of attached database hold this table
+  ** name:       Name of the table itself
+  ** type:       "table", "view", "virtual", "shadow"
+  ** ncol:       Number of columns
+  ** wr:         True for a WITHOUT ROWID table
+  ** strict:     True for a STRICT table
+  */
+  case PragTyp_TABLE_LIST: {
+    int ii;
+    pParse->nMem = 6;
+    sqlite3CodeVerifyNamedSchema(pParse, zDb);
+    for(ii=0; ii<db->nDb; ii++){
+      HashElem *k;
+      Hash *pHash;
+      int initNCol;
+      if( zDb && sqlite3_stricmp(zDb, db->aDb[ii].zDbSName)!=0 ) continue;
+
+      /* Ensure that the Table.nCol field is initialized for all views
+      ** and virtual tables.  Each time we initialize a Table.nCol value
+      ** for a table, that can potentially disrupt the hash table, so restart
+      ** the initialization scan.
+      */
+      pHash = &db->aDb[ii].pSchema->tblHash;
+      initNCol = sqliteHashCount(pHash);
+      while( initNCol-- ){
+        for(k=sqliteHashFirst(pHash); 1; k=sqliteHashNext(k) ){
+          Table *pTab;
+          if( k==0 ){ initNCol = 0; break; }
+          pTab = sqliteHashData(k);
+          if( pTab->nCol==0 ){
+            char *zSql = sqlite3MPrintf(db, "SELECT*FROM\"%w\"", pTab->zName);
+            if( zSql ){
+              sqlite3_stmt *pDummy = 0;
+              (void)sqlite3_prepare_v3(db, zSql, -1, SQLITE_PREPARE_DONT_LOG,
+                                       &pDummy, 0);
+              (void)sqlite3_finalize(pDummy);
+              sqlite3DbFree(db, zSql);
+            }
+            if( db->mallocFailed ){
+              sqlite3ErrorMsg(db->pParse, "out of memory");
+              db->pParse->rc = SQLITE_NOMEM_BKPT;
+            }
+            pHash = &db->aDb[ii].pSchema->tblHash;
+            break;
+          }
+        }
+      }
+
+      for(k=sqliteHashFirst(pHash); k; k=sqliteHashNext(k) ){
+        Table *pTab = sqliteHashData(k);
+        const char *zType;
+        if( zRight && sqlite3_stricmp(zRight, pTab->zName)!=0 ) continue;
+        if( IsView(pTab) ){
+          zType = "view";
+        }else if( IsVirtual(pTab) ){
+          zType = "virtual";
+        }else if( pTab->tabFlags & TF_Shadow ){
+          zType = "shadow";
+        }else{
+          zType = "table";
+        }
+        sqlite3VdbeMultiLoad(v, 1, "sssiii",
+           db->aDb[ii].zDbSName,
+           sqlite3PreferredTableName(pTab->zName),
+           zType,
+           pTab->nCol,
+           (pTab->tabFlags & TF_WithoutRowid)!=0,
+           (pTab->tabFlags & TF_Strict)!=0
+        );
+      }
+    }
+  }
+  break;
+
+#ifdef SQLITE_DEBUG
+  case PragTyp_STATS: {
+    Index *pIdx;
+    HashElem *i;
+    pParse->nMem = 5;
+    sqlite3CodeVerifySchema(pParse, iDb);
+    for(i=sqliteHashFirst(&pDb->pSchema->tblHash); i; i=sqliteHashNext(i)){
+      Table *pTab = sqliteHashData(i);
+      sqlite3VdbeMultiLoad(v, 1, "ssiii",
+           sqlite3PreferredTableName(pTab->zName),
+           0,
+           pTab->szTabRow,
+           pTab->nRowLogEst,
+           pTab->tabFlags);
+      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+        sqlite3VdbeMultiLoad(v, 2, "siiiX",
+           pIdx->zName,
+           pIdx->szIdxRow,
+           pIdx->aiRowLogEst[0],
+           pIdx->hasStat1);
+        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 5);
+      }
+    }
+  }
+  break;
+#endif
+
+  case PragTyp_INDEX_INFO: if( zRight ){
+    Index *pIdx;
+    Table *pTab;
+    pIdx = sqlite3FindIndex(db, zRight, zDb);
+    if( pIdx==0 ){
+      /* If there is no index named zRight, check to see if there is a
+      ** WITHOUT ROWID table named zRight, and if there is, show the
+      ** structure of the PRIMARY KEY index for that table. */
+      pTab = sqlite3LocateTable(pParse, LOCATE_NOERR, zRight, zDb);
+      if( pTab && !HasRowid(pTab) ){
+        pIdx = sqlite3PrimaryKeyIndex(pTab);
+      }
+    }
+    if( pIdx ){
+      int iIdxDb = sqlite3SchemaToIndex(db, pIdx->pSchema);
+      int i;
+      int mx;
+      if( pPragma->iArg ){
+        /* PRAGMA index_xinfo (newer version with more rows and columns) */
+        mx = pIdx->nColumn;
+        pParse->nMem = 6;
+      }else{
+        /* PRAGMA index_info (legacy version) */
+        mx = pIdx->nKeyCol;
+        pParse->nMem = 3;
+      }
+      pTab = pIdx->pTable;
+      sqlite3CodeVerifySchema(pParse, iIdxDb);
+      assert( pParse->nMem<=pPragma->nPragCName );
+      for(i=0; i<mx; i++){
+        i16 cnum = pIdx->aiColumn[i];
+        sqlite3VdbeMultiLoad(v, 1, "iisX", i, cnum,
+                             cnum<0 ? 0 : pTab->aCol[cnum].zCnName);
+        if( pPragma->iArg ){
+          sqlite3VdbeMultiLoad(v, 4, "isiX",
+            pIdx->aSortOrder[i],
+            pIdx->azColl[i],
+            i<pIdx->nKeyCol);
+        }
+        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, pParse->nMem);
+      }
+    }
+  }
+  break;
+
+  case PragTyp_INDEX_LIST: if( zRight ){
+    Index *pIdx;
+    Table *pTab;
+    int i;
+    pTab = sqlite3FindTable(db, zRight, zDb);
+    if( pTab ){
+      int iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      pParse->nMem = 5;
+      sqlite3CodeVerifySchema(pParse, iTabDb);
+      for(pIdx=pTab->pIndex, i=0; pIdx; pIdx=pIdx->pNext, i++){
+        const char *azOrigin[] = { "c", "u", "pk" };
+        sqlite3VdbeMultiLoad(v, 1, "isisi",
+           i,
+           pIdx->zName,
+           IsUniqueIndex(pIdx),
+           azOrigin[pIdx->idxType],
+           pIdx->pPartIdxWhere!=0);
+      }
+    }
+  }
+  break;
+
+  case PragTyp_DATABASE_LIST: {
+    int i;
+    pParse->nMem = 3;
+    for(i=0; i<db->nDb; i++){
+      if( db->aDb[i].pBt==0 ) continue;
+      assert( db->aDb[i].zDbSName!=0 );
+      sqlite3VdbeMultiLoad(v, 1, "iss",
+         i,
+         db->aDb[i].zDbSName,
+         sqlite3BtreeGetFilename(db->aDb[i].pBt));
+    }
+  }
+  break;
+
+  case PragTyp_COLLATION_LIST: {
+    int i = 0;
+    HashElem *p;
+    pParse->nMem = 2;
+    for(p=sqliteHashFirst(&db->aCollSeq); p; p=sqliteHashNext(p)){
+      CollSeq *pColl = (CollSeq *)sqliteHashData(p);
+      sqlite3VdbeMultiLoad(v, 1, "is", i++, pColl->zName);
+    }
+  }
+  break;
+
+#ifndef SQLITE_OMIT_INTROSPECTION_PRAGMAS
+  case PragTyp_FUNCTION_LIST: {
+    int i;
+    HashElem *j;
+    FuncDef *p;
+    int showInternFunc = (db->mDbFlags & DBFLAG_InternalFunc)!=0;
+    pParse->nMem = 6;
+    for(i=0; i<SQLITE_FUNC_HASH_SZ; i++){
+      for(p=sqlite3BuiltinFunctions.a[i]; p; p=p->u.pHash ){
+        assert( p->funcFlags & SQLITE_FUNC_BUILTIN );
+        pragmaFunclistLine(v, p, 1, showInternFunc);
+      }
+    }
+    for(j=sqliteHashFirst(&db->aFunc); j; j=sqliteHashNext(j)){
+      p = (FuncDef*)sqliteHashData(j);
+      assert( (p->funcFlags & SQLITE_FUNC_BUILTIN)==0 );
+      pragmaFunclistLine(v, p, 0, showInternFunc);
+    }
+  }
+  break;
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  case PragTyp_MODULE_LIST: {
+    HashElem *j;
+    pParse->nMem = 1;
+    for(j=sqliteHashFirst(&db->aModule); j; j=sqliteHashNext(j)){
+      Module *pMod = (Module*)sqliteHashData(j);
+      sqlite3VdbeMultiLoad(v, 1, "s", pMod->zName);
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+  case PragTyp_PRAGMA_LIST: {
+    int i;
+    for(i=0; i<ArraySize(aPragmaName); i++){
+      sqlite3VdbeMultiLoad(v, 1, "s", aPragmaName[i].zName);
+    }
+  }
+  break;
+#endif /* SQLITE_INTROSPECTION_PRAGMAS */
+
+#endif /* SQLITE_OMIT_SCHEMA_PRAGMAS */
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+  case PragTyp_FOREIGN_KEY_LIST: if( zRight ){
+    FKey *pFK;
+    Table *pTab;
+    pTab = sqlite3FindTable(db, zRight, zDb);
+    if( pTab && IsOrdinaryTable(pTab) ){
+      pFK = pTab->u.tab.pFKey;
+      if( pFK ){
+        int iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+        int i = 0;
+        pParse->nMem = 8;
+        sqlite3CodeVerifySchema(pParse, iTabDb);
+        while(pFK){
+          int j;
+          for(j=0; j<pFK->nCol; j++){
+            sqlite3VdbeMultiLoad(v, 1, "iissssss",
+                   i,
+                   j,
+                   pFK->zTo,
+                   pTab->aCol[pFK->aCol[j].iFrom].zCnName,
+                   pFK->aCol[j].zCol,
+                   actionName(pFK->aAction[1]),  /* ON UPDATE */
+                   actionName(pFK->aAction[0]),  /* ON DELETE */
+                   "NONE");
+          }
+          ++i;
+          pFK = pFK->pNextFrom;
+        }
+      }
+    }
+  }
+  break;
+#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */
+
+#ifndef SQLITE_OMIT_FOREIGN_KEY
+#ifndef SQLITE_OMIT_TRIGGER
+  case PragTyp_FOREIGN_KEY_CHECK: {
+    FKey *pFK;             /* A foreign key constraint */
+    Table *pTab;           /* Child table contain "REFERENCES" keyword */
+    Table *pParent;        /* Parent table that child points to */
+    Index *pIdx;           /* Index in the parent table */
+    int i;                 /* Loop counter:  Foreign key number for pTab */
+    int j;                 /* Loop counter:  Field of the foreign key */
+    HashElem *k;           /* Loop counter:  Next table in schema */
+    int x;                 /* result variable */
+    int regResult;         /* 3 registers to hold a result row */
+    int regRow;            /* Registers to hold a row from pTab */
+    int addrTop;           /* Top of a loop checking foreign keys */
+    int addrOk;            /* Jump here if the key is OK */
+    int *aiCols;           /* child to parent column mapping */
+
+    regResult = pParse->nMem+1;
+    pParse->nMem += 4;
+    regRow = ++pParse->nMem;
+    k = sqliteHashFirst(&db->aDb[iDb].pSchema->tblHash);
+    while( k ){
+      if( zRight ){
+        pTab = sqlite3LocateTable(pParse, 0, zRight, zDb);
+        k = 0;
+      }else{
+        pTab = (Table*)sqliteHashData(k);
+        k = sqliteHashNext(k);
+      }
+      if( pTab==0 || !IsOrdinaryTable(pTab) || pTab->u.tab.pFKey==0 ) continue;
+      iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+      zDb = db->aDb[iDb].zDbSName;
+      sqlite3CodeVerifySchema(pParse, iDb);
+      sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+      sqlite3TouchRegister(pParse, pTab->nCol+regRow);
+      sqlite3OpenTable(pParse, 0, iDb, pTab, OP_OpenRead);
+      sqlite3VdbeLoadString(v, regResult, pTab->zName);
+      assert( IsOrdinaryTable(pTab) );
+      for(i=1, pFK=pTab->u.tab.pFKey; pFK; i++, pFK=pFK->pNextFrom){
+        pParent = sqlite3FindTable(db, pFK->zTo, zDb);
+        if( pParent==0 ) continue;
+        pIdx = 0;
+        sqlite3TableLock(pParse, iDb, pParent->tnum, 0, pParent->zName);
+        x = sqlite3FkLocateIndex(pParse, pParent, pFK, &pIdx, 0);
+        if( x==0 ){
+          if( pIdx==0 ){
+            sqlite3OpenTable(pParse, i, iDb, pParent, OP_OpenRead);
+          }else{
+            sqlite3VdbeAddOp3(v, OP_OpenRead, i, pIdx->tnum, iDb);
+            sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+          }
+        }else{
+          k = 0;
+          break;
+        }
+      }
+      assert( pParse->nErr>0 || pFK==0 );
+      if( pFK ) break;
+      if( pParse->nTab<i ) pParse->nTab = i;
+      addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, 0); VdbeCoverage(v);
+      assert( IsOrdinaryTable(pTab) );
+      for(i=1, pFK=pTab->u.tab.pFKey; pFK; i++, pFK=pFK->pNextFrom){
+        pParent = sqlite3FindTable(db, pFK->zTo, zDb);
+        pIdx = 0;
+        aiCols = 0;
+        if( pParent ){
+          x = sqlite3FkLocateIndex(pParse, pParent, pFK, &pIdx, &aiCols);
+          assert( x==0 || db->mallocFailed );
+        }
+        addrOk = sqlite3VdbeMakeLabel(pParse);
+
+        /* Generate code to read the child key values into registers
+        ** regRow..regRow+n. If any of the child key values are NULL, this
+        ** row cannot cause an FK violation. Jump directly to addrOk in
+        ** this case. */
+        sqlite3TouchRegister(pParse, regRow + pFK->nCol);
+        for(j=0; j<pFK->nCol; j++){
+          int iCol = aiCols ? aiCols[j] : pFK->aCol[j].iFrom;
+          sqlite3ExprCodeGetColumnOfTable(v, pTab, 0, iCol, regRow+j);
+          sqlite3VdbeAddOp2(v, OP_IsNull, regRow+j, addrOk); VdbeCoverage(v);
+        }
+
+        /* Generate code to query the parent index for a matching parent
+        ** key. If a match is found, jump to addrOk. */
+        if( pIdx ){
+          sqlite3VdbeAddOp4(v, OP_Affinity, regRow, pFK->nCol, 0,
+              sqlite3IndexAffinityStr(db,pIdx), pFK->nCol);
+          sqlite3VdbeAddOp4Int(v, OP_Found, i, addrOk, regRow, pFK->nCol);
+          VdbeCoverage(v);
+        }else if( pParent ){
+          int jmp = sqlite3VdbeCurrentAddr(v)+2;
+          sqlite3VdbeAddOp3(v, OP_SeekRowid, i, jmp, regRow); VdbeCoverage(v);
+          sqlite3VdbeGoto(v, addrOk);
+          assert( pFK->nCol==1 || db->mallocFailed );
+        }
+
+        /* Generate code to report an FK violation to the caller. */
+        if( HasRowid(pTab) ){
+          sqlite3VdbeAddOp2(v, OP_Rowid, 0, regResult+1);
+        }else{
+          sqlite3VdbeAddOp2(v, OP_Null, 0, regResult+1);
+        }
+        sqlite3VdbeMultiLoad(v, regResult+2, "siX", pFK->zTo, i-1);
+        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, 4);
+        sqlite3VdbeResolveLabel(v, addrOk);
+        sqlite3DbFree(db, aiCols);
+      }
+      sqlite3VdbeAddOp2(v, OP_Next, 0, addrTop+1); VdbeCoverage(v);
+      sqlite3VdbeJumpHere(v, addrTop);
+    }
+  }
+  break;
+#endif /* !defined(SQLITE_OMIT_TRIGGER) */
+#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */
+
+#ifndef SQLITE_OMIT_CASE_SENSITIVE_LIKE_PRAGMA
+  /* Reinstall the LIKE and GLOB functions.  The variant of LIKE
+  ** used will be case sensitive or not depending on the RHS.
+  */
+  case PragTyp_CASE_SENSITIVE_LIKE: {
+    if( zRight ){
+      sqlite3RegisterLikeFunctions(db, sqlite3GetBoolean(zRight, 0));
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_CASE_SENSITIVE_LIKE_PRAGMA */
+
+#ifndef SQLITE_INTEGRITY_CHECK_ERROR_MAX
+# define SQLITE_INTEGRITY_CHECK_ERROR_MAX 100
+#endif
+
+#ifndef SQLITE_OMIT_INTEGRITY_CHECK
+  /*    PRAGMA integrity_check
+  **    PRAGMA integrity_check(N)
+  **    PRAGMA quick_check
+  **    PRAGMA quick_check(N)
+  **
+  ** Verify the integrity of the database.
+  **
+  ** The "quick_check" is reduced version of
+  ** integrity_check designed to detect most database corruption
+  ** without the overhead of cross-checking indexes.  Quick_check
+  ** is linear time whereas integrity_check is O(NlogN).
+  **
+  ** The maximum number of errors is 100 by default.  A different default
+  ** can be specified using a numeric parameter N.
+  **
+  ** Or, the parameter N can be the name of a table.  In that case, only
+  ** the one table named is verified.  The freelist is only verified if
+  ** the named table is "sqlite_schema" (or one of its aliases).
+  **
+  ** All schemas are checked by default.  To check just a single
+  ** schema, use the form:
+  **
+  **      PRAGMA schema.integrity_check;
+  */
+  case PragTyp_INTEGRITY_CHECK: {
+    int i, j, addr, mxErr;
+    Table *pObjTab = 0;     /* Check only this one table, if not NULL */
+
+    int isQuick = (sqlite3Tolower(zLeft[0])=='q');
+
+    /* If the PRAGMA command was of the form "PRAGMA <db>.integrity_check",
+    ** then iDb is set to the index of the database identified by <db>.
+    ** In this case, the integrity of database iDb only is verified by
+    ** the VDBE created below.
+    **
+    ** Otherwise, if the command was simply "PRAGMA integrity_check" (or
+    ** "PRAGMA quick_check"), then iDb is set to 0. In this case, set iDb
+    ** to -1 here, to indicate that the VDBE should verify the integrity
+    ** of all attached databases.  */
+    assert( iDb>=0 );
+    assert( iDb==0 || pId2->z );
+    if( pId2->z==0 ) iDb = -1;
+
+    /* Initialize the VDBE program */
+    pParse->nMem = 6;
+
+    /* Set the maximum error count */
+    mxErr = SQLITE_INTEGRITY_CHECK_ERROR_MAX;
+    if( zRight ){
+      if( sqlite3GetInt32(pValue->z, &mxErr) ){
+        if( mxErr<=0 ){
+          mxErr = SQLITE_INTEGRITY_CHECK_ERROR_MAX;
+        }
+      }else{
+        pObjTab = sqlite3LocateTable(pParse, 0, zRight,
+                      iDb>=0 ? db->aDb[iDb].zDbSName : 0);
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_Integer, mxErr-1, 1); /* reg[1] holds errors left */
+
+    /* Do an integrity check on each database file */
+    for(i=0; i<db->nDb; i++){
+      HashElem *x;     /* For looping over tables in the schema */
+      Hash *pTbls;     /* Set of all tables in the schema */
+      int *aRoot;      /* Array of root page numbers of all btrees */
+      int cnt = 0;     /* Number of entries in aRoot[] */
+
+      if( OMIT_TEMPDB && i==1 ) continue;
+      if( iDb>=0 && i!=iDb ) continue;
+
+      sqlite3CodeVerifySchema(pParse, i);
+      pParse->okConstFactor = 0;  /* tag-20230327-1 */
+
+      /* Do an integrity check of the B-Tree
+      **
+      ** Begin by finding the root pages numbers
+      ** for all tables and indices in the database.
+      */
+      assert( sqlite3SchemaMutexHeld(db, i, 0) );
+      pTbls = &db->aDb[i].pSchema->tblHash;
+      for(cnt=0, x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);  /* Current table */
+        Index *pIdx;                      /* An index on pTab */
+        int nIdx;                         /* Number of indexes on pTab */
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( HasRowid(pTab) ) cnt++;
+        for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){ cnt++; }
+      }
+      if( cnt==0 ) continue;
+      if( pObjTab ) cnt++;
+      aRoot = sqlite3DbMallocRawNN(db, sizeof(int)*(cnt+1));
+      if( aRoot==0 ) break;
+      cnt = 0;
+      if( pObjTab ) aRoot[++cnt] = 0;
+      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);
+        Index *pIdx;
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( HasRowid(pTab) ) aRoot[++cnt] = pTab->tnum;
+        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+          aRoot[++cnt] = pIdx->tnum;
+        }
+      }
+      aRoot[0] = cnt;
+
+      /* Make sure sufficient number of registers have been allocated */
+      sqlite3TouchRegister(pParse, 8+cnt);
+      sqlite3VdbeAddOp3(v, OP_Null, 0, 8, 8+cnt);
+      sqlite3ClearTempRegCache(pParse);
+
+      /* Do the b-tree integrity checks */
+      sqlite3VdbeAddOp4(v, OP_IntegrityCk, 1, cnt, 8, (char*)aRoot,P4_INTARRAY);
+      sqlite3VdbeChangeP5(v, (u16)i);
+      addr = sqlite3VdbeAddOp1(v, OP_IsNull, 2); VdbeCoverage(v);
+      sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0,
+         sqlite3MPrintf(db, "*** in database %s ***\n", db->aDb[i].zDbSName),
+         P4_DYNAMIC);
+      sqlite3VdbeAddOp3(v, OP_Concat, 2, 3, 3);
+      integrityCheckResultRow(v);
+      sqlite3VdbeJumpHere(v, addr);
+
+      /* Check that the indexes all have the right number of rows */
+      cnt = pObjTab ? 1 : 0;
+      sqlite3VdbeLoadString(v, 2, "wrong # of entries in index ");
+      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        int iTab = 0;
+        Table *pTab = sqliteHashData(x);
+        Index *pIdx;
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( HasRowid(pTab) ){
+          iTab = cnt++;
+        }else{
+          iTab = cnt;
+          for(pIdx=pTab->pIndex; ALWAYS(pIdx); pIdx=pIdx->pNext){
+            if( IsPrimaryKeyIndex(pIdx) ) break;
+            iTab++;
+          }
+        }
+        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+          if( pIdx->pPartIdxWhere==0 ){
+            addr = sqlite3VdbeAddOp3(v, OP_Eq, 8+cnt, 0, 8+iTab);
+            VdbeCoverageNeverNull(v);
+            sqlite3VdbeLoadString(v, 4, pIdx->zName);
+            sqlite3VdbeAddOp3(v, OP_Concat, 4, 2, 3);
+            integrityCheckResultRow(v);
+            sqlite3VdbeJumpHere(v, addr);
+          }
+          cnt++;
+        }
+      }
+
+      /* Make sure all the indices are constructed correctly.
+      */
+      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);
+        Index *pIdx, *pPk;
+        Index *pPrior = 0;      /* Previous index */
+        int loopTop;
+        int iDataCur, iIdxCur;
+        int r1 = -1;
+        int bStrict;            /* True for a STRICT table */
+        int r2;                 /* Previous key for WITHOUT ROWID tables */
+        int mxCol;              /* Maximum non-virtual column number */
+
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( !IsOrdinaryTable(pTab) ) continue;
+        if( isQuick || HasRowid(pTab) ){
+          pPk = 0;
+          r2 = 0;
+        }else{
+          pPk = sqlite3PrimaryKeyIndex(pTab);
+          r2 = sqlite3GetTempRange(pParse, pPk->nKeyCol);
+          sqlite3VdbeAddOp3(v, OP_Null, 1, r2, r2+pPk->nKeyCol-1);
+        }
+        sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenRead, 0,
+                                   1, 0, &iDataCur, &iIdxCur);
+        /* reg[7] counts the number of entries in the table.
+        ** reg[8+i] counts the number of entries in the i-th index
+        */
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, 7);
+        for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
+          sqlite3VdbeAddOp2(v, OP_Integer, 0, 8+j); /* index entries counter */
+        }
+        assert( pParse->nMem>=8+j );
+        assert( sqlite3NoTempsInRange(pParse,1,7+j) );
+        sqlite3VdbeAddOp2(v, OP_Rewind, iDataCur, 0); VdbeCoverage(v);
+        loopTop = sqlite3VdbeAddOp2(v, OP_AddImm, 7, 1);
+
+        /* Fetch the right-most column from the table.  This will cause
+        ** the entire record header to be parsed and sanity checked.  It
+        ** will also prepopulate the cursor column cache that is used
+        ** by the OP_IsType code, so it is a required step.
+        */
+        assert( !IsVirtual(pTab) );
+        if( HasRowid(pTab) ){
+          mxCol = -1;
+          for(j=0; j<pTab->nCol; j++){
+            if( (pTab->aCol[j].colFlags & COLFLAG_VIRTUAL)==0 ) mxCol++;
+          }
+          if( mxCol==pTab->iPKey ) mxCol--;
+        }else{
+          /* COLFLAG_VIRTUAL columns are not included in the WITHOUT ROWID
+          ** PK index column-count, so there is no need to account for them
+          ** in this case. */
+          mxCol = sqlite3PrimaryKeyIndex(pTab)->nColumn-1;
+        }
+        if( mxCol>=0 ){
+          sqlite3VdbeAddOp3(v, OP_Column, iDataCur, mxCol, 3);
+          sqlite3VdbeTypeofColumn(v, 3);
+        }
+
+        if( !isQuick ){
+          if( pPk ){
+            /* Verify WITHOUT ROWID keys are in ascending order */
+            int a1;
+            char *zErr;
+            a1 = sqlite3VdbeAddOp4Int(v, OP_IdxGT, iDataCur, 0,r2,pPk->nKeyCol);
+            VdbeCoverage(v);
+            sqlite3VdbeAddOp1(v, OP_IsNull, r2); VdbeCoverage(v);
+            zErr = sqlite3MPrintf(db,
+                   "row not in PRIMARY KEY order for %s",
+                    pTab->zName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+            integrityCheckResultRow(v);
+            sqlite3VdbeJumpHere(v, a1);
+            sqlite3VdbeJumpHere(v, a1+1);
+            for(j=0; j<pPk->nKeyCol; j++){
+              sqlite3ExprCodeLoadIndexColumn(pParse, pPk, iDataCur, j, r2+j);
+            }
+          }
+        }
+        /* Verify datatypes for all columns:
+        **
+        **   (1) NOT NULL columns may not contain a NULL
+        **   (2) Datatype must be exact for non-ANY columns in STRICT tables
+        **   (3) Datatype for TEXT columns in non-STRICT tables must be
+        **       NULL, TEXT, or BLOB.
+        **   (4) Datatype for numeric columns in non-STRICT tables must not
+        **       be a TEXT value that can be losslessly converted to numeric.
+        */
+        bStrict = (pTab->tabFlags & TF_Strict)!=0;
+        for(j=0; j<pTab->nCol; j++){
+          char *zErr;
+          Column *pCol = pTab->aCol + j;  /* The column to be checked */
+          int labelError;               /* Jump here to report an error */
+          int labelOk;                  /* Jump here if all looks ok */
+          int p1, p3, p4;               /* Operands to the OP_IsType opcode */
+          int doTypeCheck;              /* Check datatypes (besides NOT NULL) */
+
+          if( j==pTab->iPKey ) continue;
+          if( bStrict ){
+            doTypeCheck = pCol->eCType>COLTYPE_ANY;
+          }else{
+            doTypeCheck = pCol->affinity>SQLITE_AFF_BLOB;
+          }
+          if( pCol->notNull==0 && !doTypeCheck ) continue;
+
+          /* Compute the operands that will be needed for OP_IsType */
+          p4 = SQLITE_NULL;
+          if( pCol->colFlags & COLFLAG_VIRTUAL ){
+            sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, j, 3);
+            p1 = -1;
+            p3 = 3;
+          }else{
+            if( pCol->iDflt ){
+              sqlite3_value *pDfltValue = 0;
+              sqlite3ValueFromExpr(db, sqlite3ColumnExpr(pTab,pCol), ENC(db),
+                                   pCol->affinity, &pDfltValue);
+              if( pDfltValue ){
+                p4 = sqlite3_value_type(pDfltValue);
+                sqlite3ValueFree(pDfltValue);
+              }
+            }
+            p1 = iDataCur;
+            if( !HasRowid(pTab) ){
+              testcase( j!=sqlite3TableColumnToStorage(pTab, j) );
+              p3 = sqlite3TableColumnToIndex(sqlite3PrimaryKeyIndex(pTab), j);
+            }else{
+              p3 = sqlite3TableColumnToStorage(pTab,j);
+              testcase( p3!=j);
+            }
+          }
+
+          labelError = sqlite3VdbeMakeLabel(pParse);
+          labelOk = sqlite3VdbeMakeLabel(pParse);
+          if( pCol->notNull ){
+            /* (1) NOT NULL columns may not contain a NULL */
+            int jmp3;
+            int jmp2 = sqlite3VdbeAddOp4Int(v, OP_IsType, p1, labelOk, p3, p4);
+            VdbeCoverage(v);
+            if( p1<0 ){
+              sqlite3VdbeChangeP5(v, 0x0f); /* INT, REAL, TEXT, or BLOB */
+              jmp3 = jmp2;
+            }else{
+              sqlite3VdbeChangeP5(v, 0x0d); /* INT, TEXT, or BLOB */
+              /* OP_IsType does not detect NaN values in the database file
+              ** which should be treated as a NULL.  So if the header type
+              ** is REAL, we have to load the actual data using OP_Column
+              ** to reliably determine if the value is a NULL. */
+              sqlite3VdbeAddOp3(v, OP_Column, p1, p3, 3);
+              sqlite3ColumnDefault(v, pTab, j, 3);
+              jmp3 = sqlite3VdbeAddOp2(v, OP_NotNull, 3, labelOk);
+              VdbeCoverage(v);
+            }
+            zErr = sqlite3MPrintf(db, "NULL value in %s.%s", pTab->zName,
+                                pCol->zCnName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+            if( doTypeCheck ){
+              sqlite3VdbeGoto(v, labelError);
+              sqlite3VdbeJumpHere(v, jmp2);
+              sqlite3VdbeJumpHere(v, jmp3);
+            }else{
+              /* VDBE byte code will fall thru */
+            }
+          }
+          if( bStrict && doTypeCheck ){
+            /* (2) Datatype must be exact for non-ANY columns in STRICT tables*/
+            static unsigned char aStdTypeMask[] = {
+               0x1f,    /* ANY */
+               0x18,    /* BLOB */
+               0x11,    /* INT */
+               0x11,    /* INTEGER */
+               0x13,    /* REAL */
+               0x14     /* TEXT */
+            };
+            sqlite3VdbeAddOp4Int(v, OP_IsType, p1, labelOk, p3, p4);
+            assert( pCol->eCType>=1 && pCol->eCType<=sizeof(aStdTypeMask) );
+            sqlite3VdbeChangeP5(v, aStdTypeMask[pCol->eCType-1]);
+            VdbeCoverage(v);
+            zErr = sqlite3MPrintf(db, "non-%s value in %s.%s",
+                                  sqlite3StdType[pCol->eCType-1],
+                                  pTab->zName, pTab->aCol[j].zCnName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+          }else if( !bStrict && pCol->affinity==SQLITE_AFF_TEXT ){
+            /* (3) Datatype for TEXT columns in non-STRICT tables must be
+            **     NULL, TEXT, or BLOB. */
+            sqlite3VdbeAddOp4Int(v, OP_IsType, p1, labelOk, p3, p4);
+            sqlite3VdbeChangeP5(v, 0x1c); /* NULL, TEXT, or BLOB */
+            VdbeCoverage(v);
+            zErr = sqlite3MPrintf(db, "NUMERIC value in %s.%s",
+                                  pTab->zName, pTab->aCol[j].zCnName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+          }else if( !bStrict && pCol->affinity>=SQLITE_AFF_NUMERIC ){
+            /* (4) Datatype for numeric columns in non-STRICT tables must not
+            **     be a TEXT value that can be converted to numeric. */
+            sqlite3VdbeAddOp4Int(v, OP_IsType, p1, labelOk, p3, p4);
+            sqlite3VdbeChangeP5(v, 0x1b); /* NULL, INT, FLOAT, or BLOB */
+            VdbeCoverage(v);
+            if( p1>=0 ){
+              sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, j, 3);
+            }
+            sqlite3VdbeAddOp4(v, OP_Affinity, 3, 1, 0, "C", P4_STATIC);
+            sqlite3VdbeAddOp4Int(v, OP_IsType, -1, labelOk, 3, p4);
+            sqlite3VdbeChangeP5(v, 0x1c); /* NULL, TEXT, or BLOB */
+            VdbeCoverage(v);
+            zErr = sqlite3MPrintf(db, "TEXT value in %s.%s",
+                                  pTab->zName, pTab->aCol[j].zCnName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+          }
+          sqlite3VdbeResolveLabel(v, labelError);
+          integrityCheckResultRow(v);
+          sqlite3VdbeResolveLabel(v, labelOk);
+        }
+        /* Verify CHECK constraints */
+        if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
+          ExprList *pCheck = sqlite3ExprListDup(db, pTab->pCheck, 0);
+          if( db->mallocFailed==0 ){
+            int addrCkFault = sqlite3VdbeMakeLabel(pParse);
+            int addrCkOk = sqlite3VdbeMakeLabel(pParse);
+            char *zErr;
+            int k;
+            pParse->iSelfTab = iDataCur + 1;
+            for(k=pCheck->nExpr-1; k>0; k--){
+              sqlite3ExprIfFalse(pParse, pCheck->a[k].pExpr, addrCkFault, 0);
+            }
+            sqlite3ExprIfTrue(pParse, pCheck->a[0].pExpr, addrCkOk,
+                SQLITE_JUMPIFNULL);
+            sqlite3VdbeResolveLabel(v, addrCkFault);
+            pParse->iSelfTab = 0;
+            zErr = sqlite3MPrintf(db, "CHECK constraint failed in %s",
+                pTab->zName);
+            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
+            integrityCheckResultRow(v);
+            sqlite3VdbeResolveLabel(v, addrCkOk);
+          }
+          sqlite3ExprListDelete(db, pCheck);
+        }
+        if( !isQuick ){ /* Omit the remaining tests for quick_check */
+          /* Validate index entries for the current row */
+          for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
+            int jmp2, jmp3, jmp4, jmp5, label6;
+            int kk;
+            int ckUniq = sqlite3VdbeMakeLabel(pParse);
+            if( pPk==pIdx ) continue;
+            r1 = sqlite3GenerateIndexKey(pParse, pIdx, iDataCur, 0, 0, &jmp3,
+                                         pPrior, r1);
+            pPrior = pIdx;
+            sqlite3VdbeAddOp2(v, OP_AddImm, 8+j, 1);/* increment entry count */
+            /* Verify that an index entry exists for the current table row */
+            jmp2 = sqlite3VdbeAddOp4Int(v, OP_Found, iIdxCur+j, ckUniq, r1,
+                                        pIdx->nColumn); VdbeCoverage(v);
+            sqlite3VdbeLoadString(v, 3, "row ");
+            sqlite3VdbeAddOp3(v, OP_Concat, 7, 3, 3);
+            sqlite3VdbeLoadString(v, 4, " missing from index ");
+            sqlite3VdbeAddOp3(v, OP_Concat, 4, 3, 3);
+            jmp5 = sqlite3VdbeLoadString(v, 4, pIdx->zName);
+            sqlite3VdbeAddOp3(v, OP_Concat, 4, 3, 3);
+            jmp4 = integrityCheckResultRow(v);
+            sqlite3VdbeJumpHere(v, jmp2);
+
+            /* The OP_IdxRowid opcode is an optimized version of OP_Column
+            ** that extracts the rowid off the end of the index record.
+            ** But it only works correctly if index record does not have
+            ** any extra bytes at the end.  Verify that this is the case. */
+            if( HasRowid(pTab) ){
+              int jmp7;
+              sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur+j, 3);
+              jmp7 = sqlite3VdbeAddOp3(v, OP_Eq, 3, 0, r1+pIdx->nColumn-1);
+              VdbeCoverageNeverNull(v);
+              sqlite3VdbeLoadString(v, 3,
+                 "rowid not at end-of-record for row ");
+              sqlite3VdbeAddOp3(v, OP_Concat, 7, 3, 3);
+              sqlite3VdbeLoadString(v, 4, " of index ");
+              sqlite3VdbeGoto(v, jmp5-1);
+              sqlite3VdbeJumpHere(v, jmp7);
+            }
+
+            /* Any indexed columns with non-BINARY collations must still hold
+            ** the exact same text value as the table. */
+            label6 = 0;
+            for(kk=0; kk<pIdx->nKeyCol; kk++){
+              if( pIdx->azColl[kk]==sqlite3StrBINARY ) continue;
+              if( label6==0 ) label6 = sqlite3VdbeMakeLabel(pParse);
+              sqlite3VdbeAddOp3(v, OP_Column, iIdxCur+j, kk, 3);
+              sqlite3VdbeAddOp3(v, OP_Ne, 3, label6, r1+kk); VdbeCoverage(v);
+            }
+            if( label6 ){
+              int jmp6 = sqlite3VdbeAddOp0(v, OP_Goto);
+              sqlite3VdbeResolveLabel(v, label6);
+              sqlite3VdbeLoadString(v, 3, "row ");
+              sqlite3VdbeAddOp3(v, OP_Concat, 7, 3, 3);
+              sqlite3VdbeLoadString(v, 4, " values differ from index ");
+              sqlite3VdbeGoto(v, jmp5-1);
+              sqlite3VdbeJumpHere(v, jmp6);
+            }
+
+            /* For UNIQUE indexes, verify that only one entry exists with the
+            ** current key.  The entry is unique if (1) any column is NULL
+            ** or (2) the next entry has a different key */
+            if( IsUniqueIndex(pIdx) ){
+              int uniqOk = sqlite3VdbeMakeLabel(pParse);
+              int jmp6;
+              for(kk=0; kk<pIdx->nKeyCol; kk++){
+                int iCol = pIdx->aiColumn[kk];
+                assert( iCol!=XN_ROWID && iCol<pTab->nCol );
+                if( iCol>=0 && pTab->aCol[iCol].notNull ) continue;
+                sqlite3VdbeAddOp2(v, OP_IsNull, r1+kk, uniqOk);
+                VdbeCoverage(v);
+              }
+              jmp6 = sqlite3VdbeAddOp1(v, OP_Next, iIdxCur+j); VdbeCoverage(v);
+              sqlite3VdbeGoto(v, uniqOk);
+              sqlite3VdbeJumpHere(v, jmp6);
+              sqlite3VdbeAddOp4Int(v, OP_IdxGT, iIdxCur+j, uniqOk, r1,
+                                   pIdx->nKeyCol); VdbeCoverage(v);
+              sqlite3VdbeLoadString(v, 3, "non-unique entry in index ");
+              sqlite3VdbeGoto(v, jmp5);
+              sqlite3VdbeResolveLabel(v, uniqOk);
+            }
+            sqlite3VdbeJumpHere(v, jmp4);
+            sqlite3ResolvePartIdxLabel(pParse, jmp3);
+          }
+        }
+        sqlite3VdbeAddOp2(v, OP_Next, iDataCur, loopTop); VdbeCoverage(v);
+        sqlite3VdbeJumpHere(v, loopTop-1);
+        if( pPk ){
+          assert( !isQuick );
+          sqlite3ReleaseTempRange(pParse, r2, pPk->nKeyCol);
+        }
+      }
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      /* Second pass to invoke the xIntegrity method on all virtual
+      ** tables.
+      */
+      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
+        Table *pTab = sqliteHashData(x);
+        sqlite3_vtab *pVTab;
+        int a1;
+        if( pObjTab && pObjTab!=pTab ) continue;
+        if( IsOrdinaryTable(pTab) ) continue;
+        if( !IsVirtual(pTab) ) continue;
+        if( pTab->nCol<=0 ){
+          const char *zMod = pTab->u.vtab.azArg[0];
+          if( sqlite3HashFind(&db->aModule, zMod)==0 ) continue;
+        }
+        sqlite3ViewGetColumnNames(pParse, pTab);
+        if( pTab->u.vtab.p==0 ) continue;
+        pVTab = pTab->u.vtab.p->pVtab;
+        if( NEVER(pVTab==0) ) continue;
+        if( NEVER(pVTab->pModule==0) ) continue;
+        if( pVTab->pModule->iVersion<4 ) continue;
+        if( pVTab->pModule->xIntegrity==0 ) continue;
+        sqlite3VdbeAddOp3(v, OP_VCheck, i, 3, isQuick);
+        pTab->nTabRef++;
+        sqlite3VdbeAppendP4(v, pTab, P4_TABLEREF);
+        a1 = sqlite3VdbeAddOp1(v, OP_IsNull, 3); VdbeCoverage(v);
+        integrityCheckResultRow(v);
+        sqlite3VdbeJumpHere(v, a1);
+        continue;
+      }
+#endif
+    }
+    {
+      static const int iLn = VDBE_OFFSET_LINENO(2);
+      static const VdbeOpList endCode[] = {
+        { OP_AddImm,      1, 0,        0},    /* 0 */
+        { OP_IfNotZero,   1, 4,        0},    /* 1 */
+        { OP_String8,     0, 3,        0},    /* 2 */
+        { OP_ResultRow,   3, 1,        0},    /* 3 */
+        { OP_Halt,        0, 0,        0},    /* 4 */
+        { OP_String8,     0, 3,        0},    /* 5 */
+        { OP_Goto,        0, 3,        0},    /* 6 */
+      };
+      VdbeOp *aOp;
+
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(endCode), endCode, iLn);
+      if( aOp ){
+        aOp[0].p2 = 1-mxErr;
+        aOp[2].p4type = P4_STATIC;
+        aOp[2].p4.z = "ok";
+        aOp[5].p4type = P4_STATIC;
+        aOp[5].p4.z = (char*)sqlite3ErrStr(SQLITE_CORRUPT);
+      }
+      sqlite3VdbeChangeP3(v, 0, sqlite3VdbeCurrentAddr(v)-2);
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_INTEGRITY_CHECK */
+
+#ifndef SQLITE_OMIT_UTF16
+  /*
+  **   PRAGMA encoding
+  **   PRAGMA encoding = "utf-8"|"utf-16"|"utf-16le"|"utf-16be"
+  **
+  ** In its first form, this pragma returns the encoding of the main
+  ** database. If the database is not initialized, it is initialized now.
+  **
+  ** The second form of this pragma is a no-op if the main database file
+  ** has not already been initialized. In this case it sets the default
+  ** encoding that will be used for the main database file if a new file
+  ** is created. If an existing main database file is opened, then the
+  ** default text encoding for the existing database is used.
+  **
+  ** In all cases new databases created using the ATTACH command are
+  ** created to use the same default text encoding as the main database. If
+  ** the main database has not been initialized and/or created when ATTACH
+  ** is executed, this is done before the ATTACH operation.
+  **
+  ** In the second form this pragma sets the text encoding to be used in
+  ** new database files created using this database handle. It is only
+  ** useful if invoked immediately after the main database i
+  */
+  case PragTyp_ENCODING: {
+    static const struct EncName {
+      char *zName;
+      u8 enc;
+    } encnames[] = {
+      { "UTF8",     SQLITE_UTF8        },
+      { "UTF-8",    SQLITE_UTF8        },  /* Must be element [1] */
+      { "UTF-16le", SQLITE_UTF16LE     },  /* Must be element [2] */
+      { "UTF-16be", SQLITE_UTF16BE     },  /* Must be element [3] */
+      { "UTF16le",  SQLITE_UTF16LE     },
+      { "UTF16be",  SQLITE_UTF16BE     },
+      { "UTF-16",   0                  }, /* SQLITE_UTF16NATIVE */
+      { "UTF16",    0                  }, /* SQLITE_UTF16NATIVE */
+      { 0, 0 }
+    };
+    const struct EncName *pEnc;
+    if( !zRight ){    /* "PRAGMA encoding" */
+      if( sqlite3ReadSchema(pParse) ) goto pragma_out;
+      assert( encnames[SQLITE_UTF8].enc==SQLITE_UTF8 );
+      assert( encnames[SQLITE_UTF16LE].enc==SQLITE_UTF16LE );
+      assert( encnames[SQLITE_UTF16BE].enc==SQLITE_UTF16BE );
+      returnSingleText(v, encnames[ENC(pParse->db)].zName);
+    }else{                        /* "PRAGMA encoding = XXX" */
+      /* Only change the value of sqlite.enc if the database handle is not
+      ** initialized. If the main database exists, the new sqlite.enc value
+      ** will be overwritten when the schema is next loaded. If it does not
+      ** already exists, it will be created to use the new encoding value.
+      */
+      if( (db->mDbFlags & DBFLAG_EncodingFixed)==0 ){
+        for(pEnc=&encnames[0]; pEnc->zName; pEnc++){
+          if( 0==sqlite3StrICmp(zRight, pEnc->zName) ){
+            u8 enc = pEnc->enc ? pEnc->enc : SQLITE_UTF16NATIVE;
+            SCHEMA_ENC(db) = enc;
+            sqlite3SetTextEncoding(db, enc);
+            break;
+          }
+        }
+        if( !pEnc->zName ){
+          sqlite3ErrorMsg(pParse, "unsupported encoding: %s", zRight);
+        }
+      }
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_UTF16 */
+
+#ifndef SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS
+  /*
+  **   PRAGMA [schema.]schema_version
+  **   PRAGMA [schema.]schema_version = <integer>
+  **
+  **   PRAGMA [schema.]user_version
+  **   PRAGMA [schema.]user_version = <integer>
+  **
+  **   PRAGMA [schema.]freelist_count
+  **
+  **   PRAGMA [schema.]data_version
+  **
+  **   PRAGMA [schema.]application_id
+  **   PRAGMA [schema.]application_id = <integer>
+  **
+  ** The pragma's schema_version and user_version are used to set or get
+  ** the value of the schema-version and user-version, respectively. Both
+  ** the schema-version and the user-version are 32-bit signed integers
+  ** stored in the database header.
+  **
+  ** The schema-cookie is usually only manipulated internally by SQLite. It
+  ** is incremented by SQLite whenever the database schema is modified (by
+  ** creating or dropping a table or index). The schema version is used by
+  ** SQLite each time a query is executed to ensure that the internal cache
+  ** of the schema used when compiling the SQL query matches the schema of
+  ** the database against which the compiled query is actually executed.
+  ** Subverting this mechanism by using "PRAGMA schema_version" to modify
+  ** the schema-version is potentially dangerous and may lead to program
+  ** crashes or database corruption. Use with caution!
+  **
+  ** The user-version is not used internally by SQLite. It may be used by
+  ** applications for any purpose.
+  */
+  case PragTyp_HEADER_VALUE: {
+    int iCookie = pPragma->iArg;  /* Which cookie to read or write */
+    sqlite3VdbeUsesBtree(v, iDb);
+    if( zRight && (pPragma->mPragFlg & PragFlg_ReadOnly)==0 ){
+      /* Write the specified cookie value */
+      static const VdbeOpList setCookie[] = {
+        { OP_Transaction,    0,  1,  0},    /* 0 */
+        { OP_SetCookie,      0,  0,  0},    /* 1 */
+      };
+      VdbeOp *aOp;
+      sqlite3VdbeVerifyNoMallocRequired(v, ArraySize(setCookie));
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(setCookie), setCookie, 0);
+      if( ONLY_IF_REALLOC_STRESS(aOp==0) ) break;
+      aOp[0].p1 = iDb;
+      aOp[1].p1 = iDb;
+      aOp[1].p2 = iCookie;
+      aOp[1].p3 = sqlite3Atoi(zRight);
+      aOp[1].p5 = 1;
+      if( iCookie==BTREE_SCHEMA_VERSION && (db->flags & SQLITE_Defensive)!=0 ){
+        /* Do not allow the use of PRAGMA schema_version=VALUE in defensive
+        ** mode.  Change the OP_SetCookie opcode into a no-op.  */
+        aOp[1].opcode = OP_Noop;
+      }
+    }else{
+      /* Read the specified cookie value */
+      static const VdbeOpList readCookie[] = {
+        { OP_Transaction,     0,  0,  0},    /* 0 */
+        { OP_ReadCookie,      0,  1,  0},    /* 1 */
+        { OP_ResultRow,       1,  1,  0}
+      };
+      VdbeOp *aOp;
+      sqlite3VdbeVerifyNoMallocRequired(v, ArraySize(readCookie));
+      aOp = sqlite3VdbeAddOpList(v, ArraySize(readCookie),readCookie,0);
+      if( ONLY_IF_REALLOC_STRESS(aOp==0) ) break;
+      aOp[0].p1 = iDb;
+      aOp[1].p1 = iDb;
+      aOp[1].p3 = iCookie;
+      sqlite3VdbeReusable(v);
+    }
+  }
+  break;
+#endif /* SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS */
+
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+  /*
+  **   PRAGMA compile_options
+  **
+  ** Return the names of all compile-time options used in this build,
+  ** one option per row.
+  */
+  case PragTyp_COMPILE_OPTIONS: {
+    int i = 0;
+    const char *zOpt;
+    pParse->nMem = 1;
+    while( (zOpt = sqlite3_compileoption_get(i++))!=0 ){
+      sqlite3VdbeLoadString(v, 1, zOpt);
+      sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
+    }
+    sqlite3VdbeReusable(v);
+  }
+  break;
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+#ifndef SQLITE_OMIT_WAL
+  /*
+  **   PRAGMA [schema.]wal_checkpoint = passive|full|restart|truncate
+  **
+  ** Checkpoint the database.
+  */
+  case PragTyp_WAL_CHECKPOINT: {
+    int iBt = (pId2->z?iDb:SQLITE_MAX_DB);
+    int eMode = SQLITE_CHECKPOINT_PASSIVE;
+    if( zRight ){
+      if( sqlite3StrICmp(zRight, "full")==0 ){
+        eMode = SQLITE_CHECKPOINT_FULL;
+      }else if( sqlite3StrICmp(zRight, "restart")==0 ){
+        eMode = SQLITE_CHECKPOINT_RESTART;
+      }else if( sqlite3StrICmp(zRight, "truncate")==0 ){
+        eMode = SQLITE_CHECKPOINT_TRUNCATE;
+      }
+    }
+    pParse->nMem = 3;
+    sqlite3VdbeAddOp3(v, OP_Checkpoint, iBt, eMode, 1);
+    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 3);
+  }
+  break;
+
+  /*
+  **   PRAGMA wal_autocheckpoint
+  **   PRAGMA wal_autocheckpoint = N
+  **
+  ** Configure a database connection to automatically checkpoint a database
+  ** after accumulating N frames in the log. Or query for the current value
+  ** of N.
+  */
+  case PragTyp_WAL_AUTOCHECKPOINT: {
+    if( zRight ){
+      sqlite3_wal_autocheckpoint(db, sqlite3Atoi(zRight));
+    }
+    returnSingleInt(v,
+       db->xWalCallback==sqlite3WalDefaultHook ?
+           SQLITE_PTR_TO_INT(db->pWalArg) : 0);
+  }
+  break;
+#endif
+
+  /*
+  **  PRAGMA shrink_memory
+  **
+  ** IMPLEMENTATION-OF: R-23445-46109 This pragma causes the database
+  ** connection on which it is invoked to free up as much memory as it
+  ** can, by calling sqlite3_db_release_memory().
+  */
+  case PragTyp_SHRINK_MEMORY: {
+    sqlite3_db_release_memory(db);
+    break;
+  }
+
+  /*
+  **  PRAGMA optimize
+  **  PRAGMA optimize(MASK)
+  **  PRAGMA schema.optimize
+  **  PRAGMA schema.optimize(MASK)
+  **
+  ** Attempt to optimize the database.  All schemas are optimized in the first
+  ** two forms, and only the specified schema is optimized in the latter two.
+  **
+  ** The details of optimizations performed by this pragma are expected
+  ** to change and improve over time.  Applications should anticipate that
+  ** this pragma will perform new optimizations in future releases.
+  **
+  ** The optional argument is a bitmask of optimizations to perform:
+  **
+  **    0x00001    Debugging mode.  Do not actually perform any optimizations
+  **               but instead return one line of text for each optimization
+  **               that would have been done.  Off by default.
+  **
+  **    0x00002    Run ANALYZE on tables that might benefit.  On by default.
+  **               See below for additional information.
+  **
+  **    0x00010    Run all ANALYZE operations using an analysis_limit that
+  **               is the lessor of the current analysis_limit and the
+  **               SQLITE_DEFAULT_OPTIMIZE_LIMIT compile-time option.
+  **               The default value of SQLITE_DEFAULT_OPTIMIZE_LIMIT is
+  **               currently (2024-02-19) set to 2000, which is such that
+  **               the worst case run-time for PRAGMA optimize on a 100MB
+  **               database will usually be less than 100 milliseconds on
+  **               a RaspberryPI-4 class machine.  On by default.
+  **
+  **    0x10000    Look at tables to see if they need to be reanalyzed
+  **               due to growth or shrinkage even if they have not been
+  **               queried during the current connection.  Off by default.
+  **
+  ** The default MASK is and always shall be 0x0fffe.  In the current
+  ** implementation, the default mask only covers the 0x00002 optimization,
+  ** though additional optimizations that are covered by 0x0fffe might be
+  ** added in the future.  Optimizations that are off by default and must
+  ** be explicitly requested have masks of 0x10000 or greater.
+  **
+  ** DETERMINATION OF WHEN TO RUN ANALYZE
+  **
+  ** In the current implementation, a table is analyzed if only if all of
+  ** the following are true:
+  **
+  ** (1) MASK bit 0x00002 is set.
+  **
+  ** (2) The table is an ordinary table, not a virtual table or view.
+  **
+  ** (3) The table name does not begin with "sqlite_".
+  **
+  ** (4) One or more of the following is true:
+  **      (4a) The 0x10000 MASK bit is set.
+  **      (4b) One or more indexes on the table lacks an entry
+  **           in the sqlite_stat1 table.
+  **      (4c) The query planner used sqlite_stat1-style statistics for one
+  **           or more indexes of the table at some point during the lifetime
+  **           of the current connection.
+  **
+  ** (5) One or more of the following is true:
+  **      (5a) One or more indexes on the table lacks an entry
+  **           in the sqlite_stat1 table.  (Same as 4a)
+  **      (5b) The number of rows in the table has increased or decreased by
+  **           10-fold.  In other words, the current size of the table is
+  **           10 times larger than the size in sqlite_stat1 or else the
+  **           current size is less than 1/10th the size in sqlite_stat1.
+  **
+  ** The rules for when tables are analyzed are likely to change in
+  ** future releases.  Future versions of SQLite might accept a string
+  ** literal argument to this pragma that contains a mnemonic description
+  ** of the options rather than a bitmap.
+  */
+  case PragTyp_OPTIMIZE: {
+    int iDbLast;           /* Loop termination point for the schema loop */
+    int iTabCur;           /* Cursor for a table whose size needs checking */
+    HashElem *k;           /* Loop over tables of a schema */
+    Schema *pSchema;       /* The current schema */
+    Table *pTab;           /* A table in the schema */
+    Index *pIdx;           /* An index of the table */
+    LogEst szThreshold;    /* Size threshold above which reanalysis needed */
+    char *zSubSql;         /* SQL statement for the OP_SqlExec opcode */
+    u32 opMask;            /* Mask of operations to perform */
+    int nLimit;            /* Analysis limit to use */
+    int nCheck = 0;        /* Number of tables to be optimized */
+    int nBtree = 0;        /* Number of btrees to scan */
+    int nIndex;            /* Number of indexes on the current table */
+
+    if( zRight ){
+      opMask = (u32)sqlite3Atoi(zRight);
+      if( (opMask & 0x02)==0 ) break;
+    }else{
+      opMask = 0xfffe;
+    }
+    if( (opMask & 0x10)==0 ){
+      nLimit = 0;
+    }else if( db->nAnalysisLimit>0
+           && db->nAnalysisLimit<SQLITE_DEFAULT_OPTIMIZE_LIMIT ){
+      nLimit = 0;
+    }else{
+      nLimit = SQLITE_DEFAULT_OPTIMIZE_LIMIT;
+    }
+    iTabCur = pParse->nTab++;
+    for(iDbLast = zDb?iDb:db->nDb-1; iDb<=iDbLast; iDb++){
+      if( iDb==1 ) continue;
+      sqlite3CodeVerifySchema(pParse, iDb);
+      pSchema = db->aDb[iDb].pSchema;
+      for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
+        pTab = (Table*)sqliteHashData(k);
+
+        /* This only works for ordinary tables */
+        if( !IsOrdinaryTable(pTab) ) continue;
+
+        /* Do not scan system tables */
+        if( 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7) ) continue;
+
+        /* Find the size of the table as last recorded in sqlite_stat1.
+        ** If any index is unanalyzed, then the threshold is -1 to
+        ** indicate a new, unanalyzed index
+        */
+        szThreshold = pTab->nRowLogEst;
+        nIndex = 0;
+        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+          nIndex++;
+          if( !pIdx->hasStat1 ){
+            szThreshold = -1; /* Always analyze if any index lacks statistics */
+          }
+        }
+
+        /* If table pTab has not been used in a way that would benefit from
+        ** having analysis statistics during the current session, then skip it,
+        ** unless the 0x10000 MASK bit is set. */
+        if( (pTab->tabFlags & TF_MaybeReanalyze)!=0 ){
+          /* Check for size change if stat1 has been used for a query */
+        }else if( opMask & 0x10000 ){
+          /* Check for size change if 0x10000 is set */
+        }else if( pTab->pIndex!=0 && szThreshold<0 ){
+          /* Do analysis if unanalyzed indexes exists */
+        }else{
+          /* Otherwise, we can skip this table */
+          continue;
+        }
+
+        nCheck++;
+        if( nCheck==2 ){
+          /* If ANALYZE might be invoked two or more times, hold a write
+          ** transaction for efficiency */
+          sqlite3BeginWriteOperation(pParse, 0, iDb);
+        }
+        nBtree += nIndex+1;
+
+        /* Reanalyze if the table is 10 times larger or smaller than
+        ** the last analysis.  Unconditional reanalysis if there are
+        ** unanalyzed indexes. */
+        sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead);
+        if( szThreshold>=0 ){
+          const LogEst iRange = 33;   /* 10x size change */
+          sqlite3VdbeAddOp4Int(v, OP_IfSizeBetween, iTabCur,
+                         sqlite3VdbeCurrentAddr(v)+2+(opMask&1),
+                         szThreshold>=iRange ? szThreshold-iRange : -1,
+                         szThreshold+iRange);
+          VdbeCoverage(v);
+        }else{
+          sqlite3VdbeAddOp2(v, OP_Rewind, iTabCur,
+                         sqlite3VdbeCurrentAddr(v)+2+(opMask&1));
+          VdbeCoverage(v);
+        }
+        zSubSql = sqlite3MPrintf(db, "ANALYZE \"%w\".\"%w\"",
+                                 db->aDb[iDb].zDbSName, pTab->zName);
+        if( opMask & 0x01 ){
+          int r1 = sqlite3GetTempReg(pParse);
+          sqlite3VdbeAddOp4(v, OP_String8, 0, r1, 0, zSubSql, P4_DYNAMIC);
+          sqlite3VdbeAddOp2(v, OP_ResultRow, r1, 1);
+        }else{
+          sqlite3VdbeAddOp4(v, OP_SqlExec, nLimit ? 0x02 : 00, nLimit, 0,
+                            zSubSql, P4_DYNAMIC);
+        }
+      }
+    }
+    sqlite3VdbeAddOp0(v, OP_Expire);
+
+    /* In a schema with a large number of tables and indexes, scale back
+    ** the analysis_limit to avoid excess run-time in the worst case.
+    */
+    if( !db->mallocFailed && nLimit>0 && nBtree>100 ){
+      int iAddr, iEnd;
+      VdbeOp *aOp;
+      nLimit = 100*nLimit/nBtree;
+      if( nLimit<100 ) nLimit = 100;
+      aOp = sqlite3VdbeGetOp(v, 0);
+      iEnd = sqlite3VdbeCurrentAddr(v);
+      for(iAddr=0; iAddr<iEnd; iAddr++){
+        if( aOp[iAddr].opcode==OP_SqlExec ) aOp[iAddr].p2 = nLimit;
+      }
+    }
+    break;
+  }
+
+  /*
+  **   PRAGMA busy_timeout
+  **   PRAGMA busy_timeout = N
+  **
+  ** Call sqlite3_busy_timeout(db, N).  Return the current timeout value
+  ** if one is set.  If no busy handler or a different busy handler is set
+  ** then 0 is returned.  Setting the busy_timeout to 0 or negative
+  ** disables the timeout.
+  */
+  /*case PragTyp_BUSY_TIMEOUT*/ default: {
+    assert( pPragma->ePragTyp==PragTyp_BUSY_TIMEOUT );
+    if( zRight ){
+      sqlite3_busy_timeout(db, sqlite3Atoi(zRight));
+    }
+    returnSingleInt(v, db->busyTimeout);
+    break;
+  }
+
+  /*
+  **   PRAGMA soft_heap_limit
+  **   PRAGMA soft_heap_limit = N
+  **
+  ** IMPLEMENTATION-OF: R-26343-45930 This pragma invokes the
+  ** sqlite3_soft_heap_limit64() interface with the argument N, if N is
+  ** specified and is a non-negative integer.
+  ** IMPLEMENTATION-OF: R-64451-07163 The soft_heap_limit pragma always
+  ** returns the same integer that would be returned by the
+  ** sqlite3_soft_heap_limit64(-1) C-language function.
+  */
+  case PragTyp_SOFT_HEAP_LIMIT: {
+    sqlite3_int64 N;
+    if( zRight && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK ){
+      sqlite3_soft_heap_limit64(N);
+    }
+    returnSingleInt(v, sqlite3_soft_heap_limit64(-1));
+    break;
+  }
+
+  /*
+  **   PRAGMA hard_heap_limit
+  **   PRAGMA hard_heap_limit = N
+  **
+  ** Invoke sqlite3_hard_heap_limit64() to query or set the hard heap
+  ** limit.  The hard heap limit can be activated or lowered by this
+  ** pragma, but not raised or deactivated.  Only the
+  ** sqlite3_hard_heap_limit64() C-language API can raise or deactivate
+  ** the hard heap limit.  This allows an application to set a heap limit
+  ** constraint that cannot be relaxed by an untrusted SQL script.
+  */
+  case PragTyp_HARD_HEAP_LIMIT: {
+    sqlite3_int64 N;
+    if( zRight && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK ){
+      sqlite3_int64 iPrior = sqlite3_hard_heap_limit64(-1);
+      if( N>0 && (iPrior==0 || iPrior>N) ) sqlite3_hard_heap_limit64(N);
+    }
+    returnSingleInt(v, sqlite3_hard_heap_limit64(-1));
+    break;
+  }
+
+  /*
+  **   PRAGMA threads
+  **   PRAGMA threads = N
+  **
+  ** Configure the maximum number of worker threads.  Return the new
+  ** maximum, which might be less than requested.
+  */
+  case PragTyp_THREADS: {
+    sqlite3_int64 N;
+    if( zRight
+     && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK
+     && N>=0
+    ){
+      sqlite3_limit(db, SQLITE_LIMIT_WORKER_THREADS, (int)(N&0x7fffffff));
+    }
+    returnSingleInt(v, sqlite3_limit(db, SQLITE_LIMIT_WORKER_THREADS, -1));
+    break;
+  }
+
+  /*
+  **   PRAGMA analysis_limit
+  **   PRAGMA analysis_limit = N
+  **
+  ** Configure the maximum number of rows that ANALYZE will examine
+  ** in each index that it looks at.  Return the new limit.
+  */
+  case PragTyp_ANALYSIS_LIMIT: {
+    sqlite3_int64 N;
+    if( zRight
+     && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK /* IMP: R-40975-20399 */
+     && N>=0
+    ){
+      db->nAnalysisLimit = (int)(N&0x7fffffff);
+    }
+    returnSingleInt(v, db->nAnalysisLimit); /* IMP: R-57594-65522 */
+    break;
+  }
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /*
+  ** Report the current state of file logs for all databases
+  */
+  case PragTyp_LOCK_STATUS: {
+    static const char *const azLockName[] = {
+      "unlocked", "shared", "reserved", "pending", "exclusive"
+    };
+    int i;
+    pParse->nMem = 2;
+    for(i=0; i<db->nDb; i++){
+      Btree *pBt;
+      const char *zState = "unknown";
+      int j;
+      if( db->aDb[i].zDbSName==0 ) continue;
+      pBt = db->aDb[i].pBt;
+      if( pBt==0 || sqlite3BtreePager(pBt)==0 ){
+        zState = "closed";
+      }else if( sqlite3_file_control(db, i ? db->aDb[i].zDbSName : 0,
+                                     SQLITE_FCNTL_LOCKSTATE, &j)==SQLITE_OK ){
+         zState = azLockName[j];
+      }
+      sqlite3VdbeMultiLoad(v, 1, "ss", db->aDb[i].zDbSName, zState);
+    }
+    break;
+  }
+#endif
+
+#if defined(SQLITE_ENABLE_CEROD)
+  case PragTyp_ACTIVATE_EXTENSIONS: if( zRight ){
+    if( sqlite3StrNICmp(zRight, "cerod-", 6)==0 ){
+      sqlite3_activate_cerod(&zRight[6]);
+    }
+  }
+  break;
+#endif
+
+  } /* End of the PRAGMA switch */
+
+  /* The following block is a no-op unless SQLITE_DEBUG is defined. Its only
+  ** purpose is to execute assert() statements to verify that if the
+  ** PragFlg_NoColumns1 flag is set and the caller specified an argument
+  ** to the PRAGMA, the implementation has not added any OP_ResultRow
+  ** instructions to the VM.  */
+  if( (pPragma->mPragFlg & PragFlg_NoColumns1) && zRight ){
+    sqlite3VdbeVerifyNoResultRow(v);
+  }
+
+pragma_out:
+  sqlite3DbFree(db, zLeft);
+  sqlite3DbFree(db, zRight);
+}
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*****************************************************************************
+** Implementation of an eponymous virtual table that runs a pragma.
+**
+*/
+typedef struct PragmaVtab PragmaVtab;
+typedef struct PragmaVtabCursor PragmaVtabCursor;
+struct PragmaVtab {
+  sqlite3_vtab base;        /* Base class.  Must be first */
+  sqlite3 *db;              /* The database connection to which it belongs */
+  const PragmaName *pName;  /* Name of the pragma */
+  u8 nHidden;               /* Number of hidden columns */
+  u8 iHidden;               /* Index of the first hidden column */
+};
+struct PragmaVtabCursor {
+  sqlite3_vtab_cursor base; /* Base class.  Must be first */
+  sqlite3_stmt *pPragma;    /* The pragma statement to run */
+  sqlite_int64 iRowid;      /* Current rowid */
+  char *azArg[2];           /* Value of the argument and schema */
+};
+
+/*
+** Pragma virtual table module xConnect method.
+*/
+static int pragmaVtabConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  const PragmaName *pPragma = (const PragmaName*)pAux;
+  PragmaVtab *pTab = 0;
+  int rc;
+  int i, j;
+  char cSep = '(';
+  StrAccum acc;
+  char zBuf[200];
+
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+  sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
+  sqlite3_str_appendall(&acc, "CREATE TABLE x");
+  for(i=0, j=pPragma->iPragCName; i<pPragma->nPragCName; i++, j++){
+    sqlite3_str_appendf(&acc, "%c\"%s\"", cSep, pragCName[j]);
+    cSep = ',';
+  }
+  if( i==0 ){
+    sqlite3_str_appendf(&acc, "(\"%s\"", pPragma->zName);
+    i++;
+  }
+  j = 0;
+  if( pPragma->mPragFlg & PragFlg_Result1 ){
+    sqlite3_str_appendall(&acc, ",arg HIDDEN");
+    j++;
+  }
+  if( pPragma->mPragFlg & (PragFlg_SchemaOpt|PragFlg_SchemaReq) ){
+    sqlite3_str_appendall(&acc, ",schema HIDDEN");
+    j++;
+  }
+  sqlite3_str_append(&acc, ")", 1);
+  sqlite3StrAccumFinish(&acc);
+  assert( strlen(zBuf) < sizeof(zBuf)-1 );
+  rc = sqlite3_declare_vtab(db, zBuf);
+  if( rc==SQLITE_OK ){
+    pTab = (PragmaVtab*)sqlite3_malloc(sizeof(PragmaVtab));
+    if( pTab==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pTab, 0, sizeof(PragmaVtab));
+      pTab->pName = pPragma;
+      pTab->db = db;
+      pTab->iHidden = i;
+      pTab->nHidden = j;
+    }
+  }else{
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+  }
+
+  *ppVtab = (sqlite3_vtab*)pTab;
+  return rc;
+}
+
+/*
+** Pragma virtual table module xDisconnect method.
+*/
+static int pragmaVtabDisconnect(sqlite3_vtab *pVtab){
+  PragmaVtab *pTab = (PragmaVtab*)pVtab;
+  sqlite3_free(pTab);
+  return SQLITE_OK;
+}
+
+/* Figure out the best index to use to search a pragma virtual table.
+**
+** There are not really any index choices.  But we want to encourage the
+** query planner to give == constraints on as many hidden parameters as
+** possible, and especially on the first hidden parameter.  So return a
+** high cost if hidden parameters are unconstrained.
+*/
+static int pragmaVtabBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  PragmaVtab *pTab = (PragmaVtab*)tab;
+  const struct sqlite3_index_constraint *pConstraint;
+  int i, j;
+  int seen[2];
+
+  pIdxInfo->estimatedCost = (double)1;
+  if( pTab->nHidden==0 ){ return SQLITE_OK; }
+  pConstraint = pIdxInfo->aConstraint;
+  seen[0] = 0;
+  seen[1] = 0;
+  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
+    if( pConstraint->iColumn < pTab->iHidden ) continue;
+    if( pConstraint->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
+    if( pConstraint->usable==0 ) return SQLITE_CONSTRAINT;
+    j = pConstraint->iColumn - pTab->iHidden;
+    assert( j < 2 );
+    seen[j] = i+1;
+  }
+  if( seen[0]==0 ){
+    pIdxInfo->estimatedCost = (double)2147483647;
+    pIdxInfo->estimatedRows = 2147483647;
+    return SQLITE_OK;
+  }
+  j = seen[0]-1;
+  pIdxInfo->aConstraintUsage[j].argvIndex = 1;
+  pIdxInfo->aConstraintUsage[j].omit = 1;
+  pIdxInfo->estimatedCost = (double)20;
+  pIdxInfo->estimatedRows = 20;
+  if( seen[1] ){
+    j = seen[1]-1;
+    pIdxInfo->aConstraintUsage[j].argvIndex = 2;
+    pIdxInfo->aConstraintUsage[j].omit = 1;
+  }
+  return SQLITE_OK;
+}
+
+/* Create a new cursor for the pragma virtual table */
+static int pragmaVtabOpen(sqlite3_vtab *pVtab, sqlite3_vtab_cursor **ppCursor){
+  PragmaVtabCursor *pCsr;
+  pCsr = (PragmaVtabCursor*)sqlite3_malloc(sizeof(*pCsr));
+  if( pCsr==0 ) return SQLITE_NOMEM;
+  memset(pCsr, 0, sizeof(PragmaVtabCursor));
+  pCsr->base.pVtab = pVtab;
+  *ppCursor = &pCsr->base;
+  return SQLITE_OK;
+}
+
+/* Clear all content from pragma virtual table cursor. */
+static void pragmaVtabCursorClear(PragmaVtabCursor *pCsr){
+  int i;
+  sqlite3_finalize(pCsr->pPragma);
+  pCsr->pPragma = 0;
+  pCsr->iRowid = 0;
+  for(i=0; i<ArraySize(pCsr->azArg); i++){
+    sqlite3_free(pCsr->azArg[i]);
+    pCsr->azArg[i] = 0;
+  }
+}
+
+/* Close a pragma virtual table cursor */
+static int pragmaVtabClose(sqlite3_vtab_cursor *cur){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)cur;
+  pragmaVtabCursorClear(pCsr);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/* Advance the pragma virtual table cursor to the next row */
+static int pragmaVtabNext(sqlite3_vtab_cursor *pVtabCursor){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  int rc = SQLITE_OK;
+
+  /* Increment the xRowid value */
+  pCsr->iRowid++;
+  assert( pCsr->pPragma );
+  if( SQLITE_ROW!=sqlite3_step(pCsr->pPragma) ){
+    rc = sqlite3_finalize(pCsr->pPragma);
+    pCsr->pPragma = 0;
+    pragmaVtabCursorClear(pCsr);
+  }
+  return rc;
+}
+
+/*
+** Pragma virtual table module xFilter method.
+*/
+static int pragmaVtabFilter(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  PragmaVtab *pTab = (PragmaVtab*)(pVtabCursor->pVtab);
+  int rc;
+  int i, j;
+  StrAccum acc;
+  char *zSql;
+
+  UNUSED_PARAMETER(idxNum);
+  UNUSED_PARAMETER(idxStr);
+  pragmaVtabCursorClear(pCsr);
+  j = (pTab->pName->mPragFlg & PragFlg_Result1)!=0 ? 0 : 1;
+  for(i=0; i<argc; i++, j++){
+    const char *zText = (const char*)sqlite3_value_text(argv[i]);
+    assert( j<ArraySize(pCsr->azArg) );
+    assert( pCsr->azArg[j]==0 );
+    if( zText ){
+      pCsr->azArg[j] = sqlite3_mprintf("%s", zText);
+      if( pCsr->azArg[j]==0 ){
+        return SQLITE_NOMEM;
+      }
+    }
+  }
+  sqlite3StrAccumInit(&acc, 0, 0, 0, pTab->db->aLimit[SQLITE_LIMIT_SQL_LENGTH]);
+  sqlite3_str_appendall(&acc, "PRAGMA ");
+  if( pCsr->azArg[1] ){
+    sqlite3_str_appendf(&acc, "%Q.", pCsr->azArg[1]);
+  }
+  sqlite3_str_appendall(&acc, pTab->pName->zName);
+  if( pCsr->azArg[0] ){
+    sqlite3_str_appendf(&acc, "=%Q", pCsr->azArg[0]);
+  }
+  zSql = sqlite3StrAccumFinish(&acc);
+  if( zSql==0 ) return SQLITE_NOMEM;
+  rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pPragma, 0);
+  sqlite3_free(zSql);
+  if( rc!=SQLITE_OK ){
+    pTab->base.zErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pTab->db));
+    return rc;
+  }
+  return pragmaVtabNext(pVtabCursor);
+}
+
+/*
+** Pragma virtual table module xEof method.
+*/
+static int pragmaVtabEof(sqlite3_vtab_cursor *pVtabCursor){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  return (pCsr->pPragma==0);
+}
+
+/* The xColumn method simply returns the corresponding column from
+** the PRAGMA.
+*/
+static int pragmaVtabColumn(
+  sqlite3_vtab_cursor *pVtabCursor,
+  sqlite3_context *ctx,
+  int i
+){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  PragmaVtab *pTab = (PragmaVtab*)(pVtabCursor->pVtab);
+  if( i<pTab->iHidden ){
+    sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pPragma, i));
+  }else{
+    sqlite3_result_text(ctx, pCsr->azArg[i-pTab->iHidden],-1,SQLITE_TRANSIENT);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Pragma virtual table module xRowid method.
+*/
+static int pragmaVtabRowid(sqlite3_vtab_cursor *pVtabCursor, sqlite_int64 *p){
+  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
+  *p = pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/* The pragma virtual table object */
+static const sqlite3_module pragmaVtabModule = {
+  0,                           /* iVersion */
+  0,                           /* xCreate - create a table */
+  pragmaVtabConnect,           /* xConnect - connect to an existing table */
+  pragmaVtabBestIndex,         /* xBestIndex - Determine search strategy */
+  pragmaVtabDisconnect,        /* xDisconnect - Disconnect from a table */
+  0,                           /* xDestroy - Drop a table */
+  pragmaVtabOpen,              /* xOpen - open a cursor */
+  pragmaVtabClose,             /* xClose - close a cursor */
+  pragmaVtabFilter,            /* xFilter - configure scan constraints */
+  pragmaVtabNext,              /* xNext - advance a cursor */
+  pragmaVtabEof,               /* xEof */
+  pragmaVtabColumn,            /* xColumn - read data */
+  pragmaVtabRowid,             /* xRowid - read data */
+  0,                           /* xUpdate - write data */
+  0,                           /* xBegin - begin transaction */
+  0,                           /* xSync - sync transaction */
+  0,                           /* xCommit - commit transaction */
+  0,                           /* xRollback - rollback transaction */
+  0,                           /* xFindFunction - function overloading */
+  0,                           /* xRename - rename the table */
+  0,                           /* xSavepoint */
+  0,                           /* xRelease */
+  0,                           /* xRollbackTo */
+  0,                           /* xShadowName */
+  0                            /* xIntegrity */
+};
+
+/*
+** Check to see if zTabName is really the name of a pragma.  If it is,
+** then register an eponymous virtual table for that pragma and return
+** a pointer to the Module object for the new virtual table.
+*/
+SQLITE_PRIVATE Module *sqlite3PragmaVtabRegister(sqlite3 *db, const char *zName){
+  const PragmaName *pName;
+  assert( sqlite3_strnicmp(zName, "pragma_", 7)==0 );
+  pName = pragmaLocate(zName+7);
+  if( pName==0 ) return 0;
+  if( (pName->mPragFlg & (PragFlg_Result0|PragFlg_Result1))==0 ) return 0;
+  assert( sqlite3HashFind(&db->aModule, zName)==0 );
+  return sqlite3VtabCreateModule(db, zName, &pragmaVtabModule, (void*)pName, 0);
+}
+
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+#endif /* SQLITE_OMIT_PRAGMA */
+
+/************** End of pragma.c **********************************************/
+/************** Begin file prepare.c *****************************************/
+/*
+** 2005 May 25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the implementation of the sqlite3_prepare()
+** interface, and routines that contribute to loading the database schema
+** from disk.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** Fill the InitData structure with an error message that indicates
+** that the database is corrupt.
+*/
+static void corruptSchema(
+  InitData *pData,     /* Initialization context */
+  char **azObj,        /* Type and name of object being parsed */
+  const char *zExtra   /* Error information */
+){
+  sqlite3 *db = pData->db;
+  if( db->mallocFailed ){
+    pData->rc = SQLITE_NOMEM_BKPT;
+  }else if( pData->pzErrMsg[0]!=0 ){
+    /* A error message has already been generated.  Do not overwrite it */
+  }else if( pData->mInitFlags & (INITFLAG_AlterMask) ){
+    static const char *azAlterType[] = {
+       "rename",
+       "drop column",
+       "add column"
+    };
+    *pData->pzErrMsg = sqlite3MPrintf(db,
+        "error in %s %s after %s: %s", azObj[0], azObj[1],
+        azAlterType[(pData->mInitFlags&INITFLAG_AlterMask)-1],
+        zExtra
+    );
+    pData->rc = SQLITE_ERROR;
+  }else if( db->flags & SQLITE_WriteSchema ){
+    pData->rc = SQLITE_CORRUPT_BKPT;
+  }else{
+    char *z;
+    const char *zObj = azObj[1] ? azObj[1] : "?";
+    z = sqlite3MPrintf(db, "malformed database schema (%s)", zObj);
+    if( zExtra && zExtra[0] ) z = sqlite3MPrintf(db, "%z - %s", z, zExtra);
+    *pData->pzErrMsg = z;
+    pData->rc = SQLITE_CORRUPT_BKPT;
+  }
+}
+
+/*
+** Check to see if any sibling index (another index on the same table)
+** of pIndex has the same root page number, and if it does, return true.
+** This would indicate a corrupt schema.
+*/
+SQLITE_PRIVATE int sqlite3IndexHasDuplicateRootPage(Index *pIndex){
+  Index *p;
+  for(p=pIndex->pTable->pIndex; p; p=p->pNext){
+    if( p->tnum==pIndex->tnum && p!=pIndex ) return 1;
+  }
+  return 0;
+}
+
+/* forward declaration */
+static int sqlite3Prepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  u32 prepFlags,            /* Zero or more SQLITE_PREPARE_* flags */
+  Vdbe *pReprepare,         /* VM being reprepared */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+);
+
+
+/*
+** This is the callback routine for the code that initializes the
+** database.  See sqlite3Init() below for additional information.
+** This routine is also called from the OP_ParseSchema opcode of the VDBE.
+**
+** Each callback contains the following information:
+**
+**     argv[0] = type of object: "table", "index", "trigger", or "view".
+**     argv[1] = name of thing being created
+**     argv[2] = associated table if an index or trigger
+**     argv[3] = root page number for table or index. 0 for trigger or view.
+**     argv[4] = SQL text for the CREATE statement.
+**
+*/
+SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char **NotUsed){
+  InitData *pData = (InitData*)pInit;
+  sqlite3 *db = pData->db;
+  int iDb = pData->iDb;
+
+  assert( argc==5 );
+  UNUSED_PARAMETER2(NotUsed, argc);
+  assert( sqlite3_mutex_held(db->mutex) );
+  db->mDbFlags |= DBFLAG_EncodingFixed;
+  if( argv==0 ) return 0;   /* Might happen if EMPTY_RESULT_CALLBACKS are on */
+  pData->nInitRow++;
+  if( db->mallocFailed ){
+    corruptSchema(pData, argv, 0);
+    return 1;
+  }
+
+  assert( iDb>=0 && iDb<db->nDb );
+  if( argv[3]==0 ){
+    corruptSchema(pData, argv, 0);
+  }else if( argv[4]
+         && 'c'==sqlite3UpperToLower[(unsigned char)argv[4][0]]
+         && 'r'==sqlite3UpperToLower[(unsigned char)argv[4][1]] ){
+    /* Call the parser to process a CREATE TABLE, INDEX or VIEW.
+    ** But because db->init.busy is set to 1, no VDBE code is generated
+    ** or executed.  All the parser does is build the internal data
+    ** structures that describe the table, index, or view.
+    **
+    ** No other valid SQL statement, other than the variable CREATE statements,
+    ** can begin with the letters "C" and "R".  Thus, it is not possible run
+    ** any other kind of statement while parsing the schema, even a corrupt
+    ** schema.
+    */
+    int rc;
+    u8 saved_iDb = db->init.iDb;
+    sqlite3_stmt *pStmt;
+    TESTONLY(int rcp);            /* Return code from sqlite3_prepare() */
+
+    assert( db->init.busy );
+    db->init.iDb = iDb;
+    if( sqlite3GetUInt32(argv[3], &db->init.newTnum)==0
+     || (db->init.newTnum>pData->mxPage && pData->mxPage>0)
+    ){
+      if( sqlite3Config.bExtraSchemaChecks ){
+        corruptSchema(pData, argv, "invalid rootpage");
+      }
+    }
+    db->init.orphanTrigger = 0;
+    db->init.azInit = (const char**)argv;
+    pStmt = 0;
+    TESTONLY(rcp = ) sqlite3Prepare(db, argv[4], -1, 0, 0, &pStmt, 0);
+    rc = db->errCode;
+    assert( (rc&0xFF)==(rcp&0xFF) );
+    db->init.iDb = saved_iDb;
+    /* assert( saved_iDb==0 || (db->mDbFlags & DBFLAG_Vacuum)!=0 ); */
+    if( SQLITE_OK!=rc ){
+      if( db->init.orphanTrigger ){
+        assert( iDb==1 );
+      }else{
+        if( rc > pData->rc ) pData->rc = rc;
+        if( rc==SQLITE_NOMEM ){
+          sqlite3OomFault(db);
+        }else if( rc!=SQLITE_INTERRUPT && (rc&0xFF)!=SQLITE_LOCKED ){
+          corruptSchema(pData, argv, sqlite3_errmsg(db));
+        }
+      }
+    }
+    db->init.azInit = sqlite3StdType; /* Any array of string ptrs will do */
+    sqlite3_finalize(pStmt);
+  }else if( argv[1]==0 || (argv[4]!=0 && argv[4][0]!=0) ){
+    corruptSchema(pData, argv, 0);
+  }else{
+    /* If the SQL column is blank it means this is an index that
+    ** was created to be the PRIMARY KEY or to fulfill a UNIQUE
+    ** constraint for a CREATE TABLE.  The index should have already
+    ** been created when we processed the CREATE TABLE.  All we have
+    ** to do here is record the root page number for that index.
+    */
+    Index *pIndex;
+    pIndex = sqlite3FindIndex(db, argv[1], db->aDb[iDb].zDbSName);
+    if( pIndex==0 ){
+      corruptSchema(pData, argv, "orphan index");
+    }else
+    if( sqlite3GetUInt32(argv[3],&pIndex->tnum)==0
+     || pIndex->tnum<2
+     || pIndex->tnum>pData->mxPage
+     || sqlite3IndexHasDuplicateRootPage(pIndex)
+    ){
+      if( sqlite3Config.bExtraSchemaChecks ){
+        corruptSchema(pData, argv, "invalid rootpage");
+      }
+    }
+  }
+  return 0;
+}
+
+/*
+** Attempt to read the database schema and initialize internal
+** data structures for a single database file.  The index of the
+** database file is given by iDb.  iDb==0 is used for the main
+** database.  iDb==1 should never be used.  iDb>=2 is used for
+** auxiliary databases.  Return one of the SQLITE_ error codes to
+** indicate success or failure.
+*/
+SQLITE_PRIVATE int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){
+  int rc;
+  int i;
+#ifndef SQLITE_OMIT_DEPRECATED
+  int size;
+#endif
+  Db *pDb;
+  char const *azArg[6];
+  int meta[5];
+  InitData initData;
+  const char *zSchemaTabName;
+  int openedTransaction = 0;
+  int mask = ((db->mDbFlags & DBFLAG_EncodingFixed) | ~DBFLAG_EncodingFixed);
+
+  assert( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0 );
+  assert( iDb>=0 && iDb<db->nDb );
+  assert( db->aDb[iDb].pSchema );
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
+
+  db->init.busy = 1;
+
+  /* Construct the in-memory representation schema tables (sqlite_schema or
+  ** sqlite_temp_schema) by invoking the parser directly.  The appropriate
+  ** table name will be inserted automatically by the parser so we can just
+  ** use the abbreviation "x" here.  The parser will also automatically tag
+  ** the schema table as read-only. */
+  azArg[0] = "table";
+  azArg[1] = zSchemaTabName = SCHEMA_TABLE(iDb);
+  azArg[2] = azArg[1];
+  azArg[3] = "1";
+  azArg[4] = "CREATE TABLE x(type text,name text,tbl_name text,"
+                            "rootpage int,sql text)";
+  azArg[5] = 0;
+  initData.db = db;
+  initData.iDb = iDb;
+  initData.rc = SQLITE_OK;
+  initData.pzErrMsg = pzErrMsg;
+  initData.mInitFlags = mFlags;
+  initData.nInitRow = 0;
+  initData.mxPage = 0;
+  sqlite3InitCallback(&initData, 5, (char **)azArg, 0);
+  db->mDbFlags &= mask;
+  if( initData.rc ){
+    rc = initData.rc;
+    goto error_out;
+  }
+
+  /* Create a cursor to hold the database open
+  */
+  pDb = &db->aDb[iDb];
+  if( pDb->pBt==0 ){
+    assert( iDb==1 );
+    DbSetProperty(db, 1, DB_SchemaLoaded);
+    rc = SQLITE_OK;
+    goto error_out;
+  }
+
+  /* If there is not already a read-only (or read-write) transaction opened
+  ** on the b-tree database, open one now. If a transaction is opened, it
+  ** will be closed before this function returns.  */
+  sqlite3BtreeEnter(pDb->pBt);
+  if( sqlite3BtreeTxnState(pDb->pBt)==SQLITE_TXN_NONE ){
+    rc = sqlite3BtreeBeginTrans(pDb->pBt, 0, 0);
+    if( rc!=SQLITE_OK ){
+      sqlite3SetString(pzErrMsg, db, sqlite3ErrStr(rc));
+      goto initone_error_out;
+    }
+    openedTransaction = 1;
+  }
+
+  /* Get the database meta information.
+  **
+  ** Meta values are as follows:
+  **    meta[0]   Schema cookie.  Changes with each schema change.
+  **    meta[1]   File format of schema layer.
+  **    meta[2]   Size of the page cache.
+  **    meta[3]   Largest rootpage (auto/incr_vacuum mode)
+  **    meta[4]   Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE
+  **    meta[5]   User version
+  **    meta[6]   Incremental vacuum mode
+  **    meta[7]   unused
+  **    meta[8]   unused
+  **    meta[9]   unused
+  **
+  ** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
+  ** the possible values of meta[4].
+  */
+  for(i=0; i<ArraySize(meta); i++){
+    sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
+  }
+  if( (db->flags & SQLITE_ResetDatabase)!=0 ){
+    memset(meta, 0, sizeof(meta));
+  }
+  pDb->pSchema->schema_cookie = meta[BTREE_SCHEMA_VERSION-1];
+
+  /* If opening a non-empty database, check the text encoding. For the
+  ** main database, set sqlite3.enc to the encoding of the main database.
+  ** For an attached db, it is an error if the encoding is not the same
+  ** as sqlite3.enc.
+  */
+  if( meta[BTREE_TEXT_ENCODING-1] ){  /* text encoding */
+    if( iDb==0 && (db->mDbFlags & DBFLAG_EncodingFixed)==0 ){
+      u8 encoding;
+#ifndef SQLITE_OMIT_UTF16
+      /* If opening the main database, set ENC(db). */
+      encoding = (u8)meta[BTREE_TEXT_ENCODING-1] & 3;
+      if( encoding==0 ) encoding = SQLITE_UTF8;
+#else
+      encoding = SQLITE_UTF8;
+#endif
+      sqlite3SetTextEncoding(db, encoding);
+    }else{
+      /* If opening an attached database, the encoding much match ENC(db) */
+      if( (meta[BTREE_TEXT_ENCODING-1] & 3)!=ENC(db) ){
+        sqlite3SetString(pzErrMsg, db, "attached databases must use the same"
+            " text encoding as main database");
+        rc = SQLITE_ERROR;
+        goto initone_error_out;
+      }
+    }
+  }
+  pDb->pSchema->enc = ENC(db);
+
+  if( pDb->pSchema->cache_size==0 ){
+#ifndef SQLITE_OMIT_DEPRECATED
+    size = sqlite3AbsInt32(meta[BTREE_DEFAULT_CACHE_SIZE-1]);
+    if( size==0 ){ size = SQLITE_DEFAULT_CACHE_SIZE; }
+    pDb->pSchema->cache_size = size;
+#else
+    pDb->pSchema->cache_size = SQLITE_DEFAULT_CACHE_SIZE;
+#endif
+    sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
+  }
+
+  /*
+  ** file_format==1    Version 3.0.0.
+  ** file_format==2    Version 3.1.3.  // ALTER TABLE ADD COLUMN
+  ** file_format==3    Version 3.1.4.  // ditto but with non-NULL defaults
+  ** file_format==4    Version 3.3.0.  // DESC indices.  Boolean constants
+  */
+  pDb->pSchema->file_format = (u8)meta[BTREE_FILE_FORMAT-1];
+  if( pDb->pSchema->file_format==0 ){
+    pDb->pSchema->file_format = 1;
+  }
+  if( pDb->pSchema->file_format>SQLITE_MAX_FILE_FORMAT ){
+    sqlite3SetString(pzErrMsg, db, "unsupported file format");
+    rc = SQLITE_ERROR;
+    goto initone_error_out;
+  }
+
+  /* Ticket #2804:  When we open a database in the newer file format,
+  ** clear the legacy_file_format pragma flag so that a VACUUM will
+  ** not downgrade the database and thus invalidate any descending
+  ** indices that the user might have created.
+  */
+  if( iDb==0 && meta[BTREE_FILE_FORMAT-1]>=4 ){
+    db->flags &= ~(u64)SQLITE_LegacyFileFmt;
+  }
+
+  /* Read the schema information out of the schema tables
+  */
+  assert( db->init.busy );
+  initData.mxPage = sqlite3BtreeLastPage(pDb->pBt);
+  {
+    char *zSql;
+    zSql = sqlite3MPrintf(db,
+        "SELECT*FROM\"%w\".%s ORDER BY rowid",
+        db->aDb[iDb].zDbSName, zSchemaTabName);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    {
+      sqlite3_xauth xAuth;
+      xAuth = db->xAuth;
+      db->xAuth = 0;
+#endif
+      rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
+#ifndef SQLITE_OMIT_AUTHORIZATION
+      db->xAuth = xAuth;
+    }
+#endif
+    if( rc==SQLITE_OK ) rc = initData.rc;
+    sqlite3DbFree(db, zSql);
+#ifndef SQLITE_OMIT_ANALYZE
+    if( rc==SQLITE_OK ){
+      sqlite3AnalysisLoad(db, iDb);
+    }
+#endif
+  }
+  assert( pDb == &(db->aDb[iDb]) );
+  if( db->mallocFailed ){
+    rc = SQLITE_NOMEM_BKPT;
+    sqlite3ResetAllSchemasOfConnection(db);
+    pDb = &db->aDb[iDb];
+  }else
+  if( rc==SQLITE_OK || ((db->flags&SQLITE_NoSchemaError) && rc!=SQLITE_NOMEM)){
+    /* Hack: If the SQLITE_NoSchemaError flag is set, then consider
+    ** the schema loaded, even if errors (other than OOM) occurred. In
+    ** this situation the current sqlite3_prepare() operation will fail,
+    ** but the following one will attempt to compile the supplied statement
+    ** against whatever subset of the schema was loaded before the error
+    ** occurred.
+    **
+    ** The primary purpose of this is to allow access to the sqlite_schema
+    ** table even when its contents have been corrupted.
+    */
+    DbSetProperty(db, iDb, DB_SchemaLoaded);
+    rc = SQLITE_OK;
+  }
+
+  /* Jump here for an error that occurs after successfully allocating
+  ** curMain and calling sqlite3BtreeEnter(). For an error that occurs
+  ** before that point, jump to error_out.
+  */
+initone_error_out:
+  if( openedTransaction ){
+    sqlite3BtreeCommit(pDb->pBt);
+  }
+  sqlite3BtreeLeave(pDb->pBt);
+
+error_out:
+  if( rc ){
+    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
+      sqlite3OomFault(db);
+    }
+    sqlite3ResetOneSchema(db, iDb);
+  }
+  db->init.busy = 0;
+  return rc;
+}
+
+/*
+** Initialize all database files - the main database file, the file
+** used to store temporary tables, and any additional database files
+** created using ATTACH statements.  Return a success code.  If an
+** error occurs, write an error message into *pzErrMsg.
+**
+** After a database is initialized, the DB_SchemaLoaded bit is set
+** bit is set in the flags field of the Db structure.
+*/
+SQLITE_PRIVATE int sqlite3Init(sqlite3 *db, char **pzErrMsg){
+  int i, rc;
+  int commit_internal = !(db->mDbFlags&DBFLAG_SchemaChange);
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( sqlite3BtreeHoldsMutex(db->aDb[0].pBt) );
+  assert( db->init.busy==0 );
+  ENC(db) = SCHEMA_ENC(db);
+  assert( db->nDb>0 );
+  /* Do the main schema first */
+  if( !DbHasProperty(db, 0, DB_SchemaLoaded) ){
+    rc = sqlite3InitOne(db, 0, pzErrMsg, 0);
+    if( rc ) return rc;
+  }
+  /* All other schemas after the main schema. The "temp" schema must be last */
+  for(i=db->nDb-1; i>0; i--){
+    assert( i==1 || sqlite3BtreeHoldsMutex(db->aDb[i].pBt) );
+    if( !DbHasProperty(db, i, DB_SchemaLoaded) ){
+      rc = sqlite3InitOne(db, i, pzErrMsg, 0);
+      if( rc ) return rc;
+    }
+  }
+  if( commit_internal ){
+    sqlite3CommitInternalChanges(db);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This routine is a no-op if the database schema is already initialized.
+** Otherwise, the schema is loaded. An error code is returned.
+*/
+SQLITE_PRIVATE int sqlite3ReadSchema(Parse *pParse){
+  int rc = SQLITE_OK;
+  sqlite3 *db = pParse->db;
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( !db->init.busy ){
+    rc = sqlite3Init(db, &pParse->zErrMsg);
+    if( rc!=SQLITE_OK ){
+      pParse->rc = rc;
+      pParse->nErr++;
+    }else if( db->noSharedCache ){
+      db->mDbFlags |= DBFLAG_SchemaKnownOk;
+    }
+  }
+  return rc;
+}
+
+
+/*
+** Check schema cookies in all databases.  If any cookie is out
+** of date set pParse->rc to SQLITE_SCHEMA.  If all schema cookies
+** make no changes to pParse->rc.
+*/
+static void schemaIsValid(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  int iDb;
+  int rc;
+  int cookie;
+
+  assert( pParse->checkSchema );
+  assert( sqlite3_mutex_held(db->mutex) );
+  for(iDb=0; iDb<db->nDb; iDb++){
+    int openedTransaction = 0;         /* True if a transaction is opened */
+    Btree *pBt = db->aDb[iDb].pBt;     /* Btree database to read cookie from */
+    if( pBt==0 ) continue;
+
+    /* If there is not already a read-only (or read-write) transaction opened
+    ** on the b-tree database, open one now. If a transaction is opened, it
+    ** will be closed immediately after reading the meta-value. */
+    if( sqlite3BtreeTxnState(pBt)==SQLITE_TXN_NONE ){
+      rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
+      if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
+        sqlite3OomFault(db);
+        pParse->rc = SQLITE_NOMEM;
+      }
+      if( rc!=SQLITE_OK ) return;
+      openedTransaction = 1;
+    }
+
+    /* Read the schema cookie from the database. If it does not match the
+    ** value stored as part of the in-memory schema representation,
+    ** set Parse.rc to SQLITE_SCHEMA. */
+    sqlite3BtreeGetMeta(pBt, BTREE_SCHEMA_VERSION, (u32 *)&cookie);
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( cookie!=db->aDb[iDb].pSchema->schema_cookie ){
+      if( DbHasProperty(db, iDb, DB_SchemaLoaded) ) pParse->rc = SQLITE_SCHEMA;
+      sqlite3ResetOneSchema(db, iDb);
+    }
+
+    /* Close the transaction, if one was opened. */
+    if( openedTransaction ){
+      sqlite3BtreeCommit(pBt);
+    }
+  }
+}
+
+/*
+** Convert a schema pointer into the iDb index that indicates
+** which database file in db->aDb[] the schema refers to.
+**
+** If the same database is attached more than once, the first
+** attached database is returned.
+*/
+SQLITE_PRIVATE int sqlite3SchemaToIndex(sqlite3 *db, Schema *pSchema){
+  int i = -32768;
+
+  /* If pSchema is NULL, then return -32768. This happens when code in
+  ** expr.c is trying to resolve a reference to a transient table (i.e. one
+  ** created by a sub-select). In this case the return value of this
+  ** function should never be used.
+  **
+  ** We return -32768 instead of the more usual -1 simply because using
+  ** -32768 as the incorrect index into db->aDb[] is much
+  ** more likely to cause a segfault than -1 (of course there are assert()
+  ** statements too, but it never hurts to play the odds) and
+  ** -32768 will still fit into a 16-bit signed integer.
+  */
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( pSchema ){
+    for(i=0; 1; i++){
+      assert( i<db->nDb );
+      if( db->aDb[i].pSchema==pSchema ){
+        break;
+      }
+    }
+    assert( i>=0 && i<db->nDb );
+  }
+  return i;
+}
+
+/*
+** Free all memory allocations in the pParse object
+*/
+SQLITE_PRIVATE void sqlite3ParseObjectReset(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  assert( db!=0 );
+  assert( db->pParse==pParse );
+  assert( pParse->nested==0 );
+#ifndef SQLITE_OMIT_SHARED_CACHE
+  if( pParse->aTableLock ) sqlite3DbNNFreeNN(db, pParse->aTableLock);
+#endif
+  while( pParse->pCleanup ){
+    ParseCleanup *pCleanup = pParse->pCleanup;
+    pParse->pCleanup = pCleanup->pNext;
+    pCleanup->xCleanup(db, pCleanup->pPtr);
+    sqlite3DbNNFreeNN(db, pCleanup);
+  }
+  if( pParse->aLabel ) sqlite3DbNNFreeNN(db, pParse->aLabel);
+  if( pParse->pConstExpr ){
+    sqlite3ExprListDelete(db, pParse->pConstExpr);
+  }
+  assert( db->lookaside.bDisable >= pParse->disableLookaside );
+  db->lookaside.bDisable -= pParse->disableLookaside;
+  db->lookaside.sz = db->lookaside.bDisable ? 0 : db->lookaside.szTrue;
+  assert( pParse->db->pParse==pParse );
+  db->pParse = pParse->pOuterParse;
+}
+
+/*
+** Add a new cleanup operation to a Parser.  The cleanup should happen when
+** the parser object is destroyed.  But, beware: the cleanup might happen
+** immediately.
+**
+** Use this mechanism for uncommon cleanups.  There is a higher setup
+** cost for this mechanism (an extra malloc), so it should not be used
+** for common cleanups that happen on most calls.  But for less
+** common cleanups, we save a single NULL-pointer comparison in
+** sqlite3ParseObjectReset(), which reduces the total CPU cycle count.
+**
+** If a memory allocation error occurs, then the cleanup happens immediately.
+** When either SQLITE_DEBUG or SQLITE_COVERAGE_TEST are defined, the
+** pParse->earlyCleanup flag is set in that case.  Calling code show verify
+** that test cases exist for which this happens, to guard against possible
+** use-after-free errors following an OOM.  The preferred way to do this is
+** to immediately follow the call to this routine with:
+**
+**       testcase( pParse->earlyCleanup );
+**
+** This routine returns a copy of its pPtr input (the third parameter)
+** except if an early cleanup occurs, in which case it returns NULL.  So
+** another way to check for early cleanup is to check the return value.
+** Or, stop using the pPtr parameter with this call and use only its
+** return value thereafter.  Something like this:
+**
+**       pObj = sqlite3ParserAddCleanup(pParse, destructor, pObj);
+*/
+SQLITE_PRIVATE void *sqlite3ParserAddCleanup(
+  Parse *pParse,                      /* Destroy when this Parser finishes */
+  void (*xCleanup)(sqlite3*,void*),   /* The cleanup routine */
+  void *pPtr                          /* Pointer to object to be cleaned up */
+){
+  ParseCleanup *pCleanup;
+  if( sqlite3FaultSim(300) ){
+    pCleanup = 0;
+    sqlite3OomFault(pParse->db);
+  }else{
+    pCleanup = sqlite3DbMallocRaw(pParse->db, sizeof(*pCleanup));
+  }
+  if( pCleanup ){
+    pCleanup->pNext = pParse->pCleanup;
+    pParse->pCleanup = pCleanup;
+    pCleanup->pPtr = pPtr;
+    pCleanup->xCleanup = xCleanup;
+  }else{
+    xCleanup(pParse->db, pPtr);
+    pPtr = 0;
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+    pParse->earlyCleanup = 1;
+#endif
+  }
+  return pPtr;
+}
+
+/*
+** Turn bulk memory into a valid Parse object and link that Parse object
+** into database connection db.
+**
+** Call sqlite3ParseObjectReset() to undo this operation.
+**
+** Caution:  Do not confuse this routine with sqlite3ParseObjectInit() which
+** is generated by Lemon.
+*/
+SQLITE_PRIVATE void sqlite3ParseObjectInit(Parse *pParse, sqlite3 *db){
+  memset(PARSE_HDR(pParse), 0, PARSE_HDR_SZ);
+  memset(PARSE_TAIL(pParse), 0, PARSE_TAIL_SZ);
+  assert( db->pParse!=pParse );
+  pParse->pOuterParse = db->pParse;
+  db->pParse = pParse;
+  pParse->db = db;
+  if( db->mallocFailed ) sqlite3ErrorMsg(pParse, "out of memory");
+}
+
+/*
+** Maximum number of times that we will try again to prepare a statement
+** that returns SQLITE_ERROR_RETRY.
+*/
+#ifndef SQLITE_MAX_PREPARE_RETRY
+# define SQLITE_MAX_PREPARE_RETRY 25
+#endif
+
+/*
+** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
+*/
+static int sqlite3Prepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  u32 prepFlags,            /* Zero or more SQLITE_PREPARE_* flags */
+  Vdbe *pReprepare,         /* VM being reprepared */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc = SQLITE_OK;       /* Result code */
+  int i;                    /* Loop counter */
+  Parse sParse;             /* Parsing context */
+
+  /* sqlite3ParseObjectInit(&sParse, db); // inlined for performance */
+  memset(PARSE_HDR(&sParse), 0, PARSE_HDR_SZ);
+  memset(PARSE_TAIL(&sParse), 0, PARSE_TAIL_SZ);
+  sParse.pOuterParse = db->pParse;
+  db->pParse = &sParse;
+  sParse.db = db;
+  if( pReprepare ){
+    sParse.pReprepare = pReprepare;
+    sParse.explain = sqlite3_stmt_isexplain((sqlite3_stmt*)pReprepare);
+  }else{
+    assert( sParse.pReprepare==0 );
+  }
+  assert( ppStmt && *ppStmt==0 );
+  if( db->mallocFailed ){
+    sqlite3ErrorMsg(&sParse, "out of memory");
+    db->errCode = rc = SQLITE_NOMEM;
+    goto end_prepare;
+  }
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  /* For a long-term use prepared statement avoid the use of
+  ** lookaside memory.
+  */
+  if( prepFlags & SQLITE_PREPARE_PERSISTENT ){
+    sParse.disableLookaside++;
+    DisableLookaside;
+  }
+  sParse.prepFlags = prepFlags & 0xff;
+
+  /* Check to verify that it is possible to get a read lock on all
+  ** database schemas.  The inability to get a read lock indicates that
+  ** some other database connection is holding a write-lock, which in
+  ** turn means that the other connection has made uncommitted changes
+  ** to the schema.
+  **
+  ** Were we to proceed and prepare the statement against the uncommitted
+  ** schema changes and if those schema changes are subsequently rolled
+  ** back and different changes are made in their place, then when this
+  ** prepared statement goes to run the schema cookie would fail to detect
+  ** the schema change.  Disaster would follow.
+  **
+  ** This thread is currently holding mutexes on all Btrees (because
+  ** of the sqlite3BtreeEnterAll() in sqlite3LockAndPrepare()) so it
+  ** is not possible for another thread to start a new schema change
+  ** while this routine is running.  Hence, we do not need to hold
+  ** locks on the schema, we just need to make sure nobody else is
+  ** holding them.
+  **
+  ** Note that setting READ_UNCOMMITTED overrides most lock detection,
+  ** but it does *not* override schema lock detection, so this all still
+  ** works even if READ_UNCOMMITTED is set.
+  */
+  if( !db->noSharedCache ){
+    for(i=0; i<db->nDb; i++) {
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        assert( sqlite3BtreeHoldsMutex(pBt) );
+        rc = sqlite3BtreeSchemaLocked(pBt);
+        if( rc ){
+          const char *zDb = db->aDb[i].zDbSName;
+          sqlite3ErrorWithMsg(db, rc, "database schema is locked: %s", zDb);
+          testcase( db->flags & SQLITE_ReadUncommit );
+          goto end_prepare;
+        }
+      }
+    }
+  }
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( db->pDisconnect ) sqlite3VtabUnlockList(db);
+#endif
+
+  if( nBytes>=0 && (nBytes==0 || zSql[nBytes-1]!=0) ){
+    char *zSqlCopy;
+    int mxLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
+    testcase( nBytes==mxLen );
+    testcase( nBytes==mxLen+1 );
+    if( nBytes>mxLen ){
+      sqlite3ErrorWithMsg(db, SQLITE_TOOBIG, "statement too long");
+      rc = sqlite3ApiExit(db, SQLITE_TOOBIG);
+      goto end_prepare;
+    }
+    zSqlCopy = sqlite3DbStrNDup(db, zSql, nBytes);
+    if( zSqlCopy ){
+      sqlite3RunParser(&sParse, zSqlCopy);
+      sParse.zTail = &zSql[sParse.zTail-zSqlCopy];
+      sqlite3DbFree(db, zSqlCopy);
+    }else{
+      sParse.zTail = &zSql[nBytes];
+    }
+  }else{
+    sqlite3RunParser(&sParse, zSql);
+  }
+  assert( 0==sParse.nQueryLoop );
+
+  if( pzTail ){
+    *pzTail = sParse.zTail;
+  }
+
+  if( db->init.busy==0 ){
+    sqlite3VdbeSetSql(sParse.pVdbe, zSql, (int)(sParse.zTail-zSql), prepFlags);
+  }
+  if( db->mallocFailed ){
+    sParse.rc = SQLITE_NOMEM_BKPT;
+    sParse.checkSchema = 0;
+  }
+  if( sParse.rc!=SQLITE_OK && sParse.rc!=SQLITE_DONE ){
+    if( sParse.checkSchema && db->init.busy==0 ){
+      schemaIsValid(&sParse);
+    }
+    if( sParse.pVdbe ){
+      sqlite3VdbeFinalize(sParse.pVdbe);
+    }
+    assert( 0==(*ppStmt) );
+    rc = sParse.rc;
+    if( sParse.zErrMsg ){
+      sqlite3ErrorWithMsg(db, rc, "%s", sParse.zErrMsg);
+      sqlite3DbFree(db, sParse.zErrMsg);
+    }else{
+      sqlite3Error(db, rc);
+    }
+  }else{
+    assert( sParse.zErrMsg==0 );
+    *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
+    rc = SQLITE_OK;
+    sqlite3ErrorClear(db);
+  }
+
+
+  /* Delete any TriggerPrg structures allocated while parsing this statement. */
+  while( sParse.pTriggerPrg ){
+    TriggerPrg *pT = sParse.pTriggerPrg;
+    sParse.pTriggerPrg = pT->pNext;
+    sqlite3DbFree(db, pT);
+  }
+
+end_prepare:
+
+  sqlite3ParseObjectReset(&sParse);
+  return rc;
+}
+static int sqlite3LockAndPrepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  u32 prepFlags,            /* Zero or more SQLITE_PREPARE_* flags */
+  Vdbe *pOld,               /* VM being reprepared */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  int cnt = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppStmt==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *ppStmt = 0;
+  if( !sqlite3SafetyCheckOk(db)||zSql==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  do{
+    /* Make multiple attempts to compile the SQL, until it either succeeds
+    ** or encounters a permanent error.  A schema problem after one schema
+    ** reset is considered a permanent error. */
+    rc = sqlite3Prepare(db, zSql, nBytes, prepFlags, pOld, ppStmt, pzTail);
+    assert( rc==SQLITE_OK || *ppStmt==0 );
+    if( rc==SQLITE_OK || db->mallocFailed ) break;
+  }while( (rc==SQLITE_ERROR_RETRY && (cnt++)<SQLITE_MAX_PREPARE_RETRY)
+       || (rc==SQLITE_SCHEMA && (sqlite3ResetOneSchema(db,-1), cnt++)==0) );
+  sqlite3BtreeLeaveAll(db);
+  rc = sqlite3ApiExit(db, rc);
+  assert( (rc&db->errMask)==rc );
+  db->busyHandler.nBusy = 0;
+  sqlite3_mutex_leave(db->mutex);
+  assert( rc==SQLITE_OK || (*ppStmt)==0 );
+  return rc;
+}
+
+
+/*
+** Rerun the compilation of a statement after a schema change.
+**
+** If the statement is successfully recompiled, return SQLITE_OK. Otherwise,
+** if the statement cannot be recompiled because another connection has
+** locked the sqlite3_schema table, return SQLITE_LOCKED. If any other error
+** occurs, return SQLITE_SCHEMA.
+*/
+SQLITE_PRIVATE int sqlite3Reprepare(Vdbe *p){
+  int rc;
+  sqlite3_stmt *pNew;
+  const char *zSql;
+  sqlite3 *db;
+  u8 prepFlags;
+
+  assert( sqlite3_mutex_held(sqlite3VdbeDb(p)->mutex) );
+  zSql = sqlite3_sql((sqlite3_stmt *)p);
+  assert( zSql!=0 );  /* Reprepare only called for prepare_v2() statements */
+  db = sqlite3VdbeDb(p);
+  assert( sqlite3_mutex_held(db->mutex) );
+  prepFlags = sqlite3VdbePrepareFlags(p);
+  rc = sqlite3LockAndPrepare(db, zSql, -1, prepFlags, p, &pNew, 0);
+  if( rc ){
+    if( rc==SQLITE_NOMEM ){
+      sqlite3OomFault(db);
+    }
+    assert( pNew==0 );
+    return rc;
+  }else{
+    assert( pNew!=0 );
+  }
+  sqlite3VdbeSwap((Vdbe*)pNew, p);
+  sqlite3TransferBindings(pNew, (sqlite3_stmt*)p);
+  sqlite3VdbeResetStepResult((Vdbe*)pNew);
+  sqlite3VdbeFinalize((Vdbe*)pNew);
+  return SQLITE_OK;
+}
+
+
+/*
+** Two versions of the official API.  Legacy and new use.  In the legacy
+** version, the original SQL text is not saved in the prepared statement
+** and so if a schema change occurs, SQLITE_SCHEMA is returned by
+** sqlite3_step().  In the new version, the original SQL text is retained
+** and the statement is automatically recompiled if an schema change
+** occurs.
+*/
+SQLITE_API int sqlite3_prepare(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,0,0,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+SQLITE_API int sqlite3_prepare_v2(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  /* EVIDENCE-OF: R-37923-12173 The sqlite3_prepare_v2() interface works
+  ** exactly the same as sqlite3_prepare_v3() with a zero prepFlags
+  ** parameter.
+  **
+  ** Proof in that the 5th parameter to sqlite3LockAndPrepare is 0 */
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,SQLITE_PREPARE_SAVESQL,0,
+                             ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );
+  return rc;
+}
+SQLITE_API int sqlite3_prepare_v3(
+  sqlite3 *db,              /* Database handle. */
+  const char *zSql,         /* UTF-8 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  unsigned int prepFlags,   /* Zero or more SQLITE_PREPARE_* flags */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const char **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  /* EVIDENCE-OF: R-56861-42673 sqlite3_prepare_v3() differs from
+  ** sqlite3_prepare_v2() only in having the extra prepFlags parameter,
+  ** which is a bit array consisting of zero or more of the
+  ** SQLITE_PREPARE_* flags.
+  **
+  ** Proof by comparison to the implementation of sqlite3_prepare_v2()
+  ** directly above. */
+  rc = sqlite3LockAndPrepare(db,zSql,nBytes,
+                 SQLITE_PREPARE_SAVESQL|(prepFlags&SQLITE_PREPARE_MASK),
+                 0,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );
+  return rc;
+}
+
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Compile the UTF-16 encoded SQL statement zSql into a statement handle.
+*/
+static int sqlite3Prepare16(
+  sqlite3 *db,              /* Database handle. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  u32 prepFlags,            /* Zero or more SQLITE_PREPARE_* flags */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  /* This function currently works by first transforming the UTF-16
+  ** encoded string to UTF-8, then invoking sqlite3_prepare(). The
+  ** tricky bit is figuring out the pointer to return in *pzTail.
+  */
+  char *zSql8;
+  const char *zTail8 = 0;
+  int rc = SQLITE_OK;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppStmt==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *ppStmt = 0;
+  if( !sqlite3SafetyCheckOk(db)||zSql==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  /* Make sure nBytes is non-negative and correct.  It should be the
+  ** number of bytes until the end of the input buffer or until the first
+  ** U+0000 character.  If the input nBytes is odd, convert it into
+  ** an even number.  If the input nBytes is negative, then the input
+  ** must be terminated by at least one U+0000 character */
+  if( nBytes>=0 ){
+    int sz;
+    const char *z = (const char*)zSql;
+    for(sz=0; sz<nBytes && (z[sz]!=0 || z[sz+1]!=0); sz += 2){}
+    nBytes = sz;
+  }else{
+    int sz;
+    const char *z = (const char*)zSql;
+    for(sz=0; z[sz]!=0 || z[sz+1]!=0; sz += 2){}
+    nBytes = sz;
+  }
+
+  sqlite3_mutex_enter(db->mutex);
+  zSql8 = sqlite3Utf16to8(db, zSql, nBytes, SQLITE_UTF16NATIVE);
+  if( zSql8 ){
+    rc = sqlite3LockAndPrepare(db, zSql8, -1, prepFlags, 0, ppStmt, &zTail8);
+  }
+
+  if( zTail8 && pzTail ){
+    /* If sqlite3_prepare returns a tail pointer, we calculate the
+    ** equivalent pointer into the UTF-16 string by counting the unicode
+    ** characters between zSql8 and zTail8, and then returning a pointer
+    ** the same number of characters into the UTF-16 string.
+    */
+    int chars_parsed = sqlite3Utf8CharLen(zSql8, (int)(zTail8-zSql8));
+    *pzTail = (u8 *)zSql + sqlite3Utf16ByteLen(zSql, nBytes, chars_parsed);
+  }
+  sqlite3DbFree(db, zSql8);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Two versions of the official API.  Legacy and new use.  In the legacy
+** version, the original SQL text is not saved in the prepared statement
+** and so if a schema change occurs, SQLITE_SCHEMA is returned by
+** sqlite3_step().  In the new version, the original SQL text is retained
+** and the statement is automatically recompiled if an schema change
+** occurs.
+*/
+SQLITE_API int sqlite3_prepare16(
+  sqlite3 *db,              /* Database handle. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3Prepare16(db,zSql,nBytes,0,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+SQLITE_API int sqlite3_prepare16_v2(
+  sqlite3 *db,              /* Database handle. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3Prepare16(db,zSql,nBytes,SQLITE_PREPARE_SAVESQL,ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+SQLITE_API int sqlite3_prepare16_v3(
+  sqlite3 *db,              /* Database handle. */
+  const void *zSql,         /* UTF-16 encoded SQL statement. */
+  int nBytes,               /* Length of zSql in bytes. */
+  unsigned int prepFlags,   /* Zero or more SQLITE_PREPARE_* flags */
+  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
+  const void **pzTail       /* OUT: End of parsed string */
+){
+  int rc;
+  rc = sqlite3Prepare16(db,zSql,nBytes,
+         SQLITE_PREPARE_SAVESQL|(prepFlags&SQLITE_PREPARE_MASK),
+         ppStmt,pzTail);
+  assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
+  return rc;
+}
+
+#endif /* SQLITE_OMIT_UTF16 */
+
+/************** End of prepare.c *********************************************/
+/************** Begin file select.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle SELECT statements in SQLite.
+*/
+/* #include "sqliteInt.h" */
+
+/*
+** An instance of the following object is used to record information about
+** how to process the DISTINCT keyword, to simplify passing that information
+** into the selectInnerLoop() routine.
+*/
+typedef struct DistinctCtx DistinctCtx;
+struct DistinctCtx {
+  u8 isTnct;      /* 0: Not distinct. 1: DISTICT  2: DISTINCT and ORDER BY */
+  u8 eTnctType;   /* One of the WHERE_DISTINCT_* operators */
+  int tabTnct;    /* Ephemeral table used for DISTINCT processing */
+  int addrTnct;   /* Address of OP_OpenEphemeral opcode for tabTnct */
+};
+
+/*
+** An instance of the following object is used to record information about
+** the ORDER BY (or GROUP BY) clause of query is being coded.
+**
+** The aDefer[] array is used by the sorter-references optimization. For
+** example, assuming there is no index that can be used for the ORDER BY,
+** for the query:
+**
+**     SELECT a, bigblob FROM t1 ORDER BY a LIMIT 10;
+**
+** it may be more efficient to add just the "a" values to the sorter, and
+** retrieve the associated "bigblob" values directly from table t1 as the
+** 10 smallest "a" values are extracted from the sorter.
+**
+** When the sorter-reference optimization is used, there is one entry in the
+** aDefer[] array for each database table that may be read as values are
+** extracted from the sorter.
+*/
+typedef struct SortCtx SortCtx;
+struct SortCtx {
+  ExprList *pOrderBy;   /* The ORDER BY (or GROUP BY clause) */
+  int nOBSat;           /* Number of ORDER BY terms satisfied by indices */
+  int iECursor;         /* Cursor number for the sorter */
+  int regReturn;        /* Register holding block-output return address */
+  int labelBkOut;       /* Start label for the block-output subroutine */
+  int addrSortIndex;    /* Address of the OP_SorterOpen or OP_OpenEphemeral */
+  int labelDone;        /* Jump here when done, ex: LIMIT reached */
+  int labelOBLopt;      /* Jump here when sorter is full */
+  u8 sortFlags;         /* Zero or more SORTFLAG_* bits */
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  u8 nDefer;            /* Number of valid entries in aDefer[] */
+  struct DeferredCsr {
+    Table *pTab;        /* Table definition */
+    int iCsr;           /* Cursor number for table */
+    int nKey;           /* Number of PK columns for table pTab (>=1) */
+  } aDefer[4];
+#endif
+  struct RowLoadInfo *pDeferredRowLoad;  /* Deferred row loading info or NULL */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrPush;         /* First instruction to push data into sorter */
+  int addrPushEnd;      /* Last instruction that pushes data into sorter */
+#endif
+};
+#define SORTFLAG_UseSorter  0x01   /* Use SorterOpen instead of OpenEphemeral */
+
+/*
+** Delete all the content of a Select structure.  Deallocate the structure
+** itself depending on the value of bFree
+**
+** If bFree==1, call sqlite3DbFree() on the p object.
+** If bFree==0, Leave the first Select object unfreed
+*/
+static void clearSelect(sqlite3 *db, Select *p, int bFree){
+  assert( db!=0 );
+  while( p ){
+    Select *pPrior = p->pPrior;
+    sqlite3ExprListDelete(db, p->pEList);
+    sqlite3SrcListDelete(db, p->pSrc);
+    sqlite3ExprDelete(db, p->pWhere);
+    sqlite3ExprListDelete(db, p->pGroupBy);
+    sqlite3ExprDelete(db, p->pHaving);
+    sqlite3ExprListDelete(db, p->pOrderBy);
+    sqlite3ExprDelete(db, p->pLimit);
+    if( OK_IF_ALWAYS_TRUE(p->pWith) ) sqlite3WithDelete(db, p->pWith);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( OK_IF_ALWAYS_TRUE(p->pWinDefn) ){
+      sqlite3WindowListDelete(db, p->pWinDefn);
+    }
+    while( p->pWin ){
+      assert( p->pWin->ppThis==&p->pWin );
+      sqlite3WindowUnlinkFromSelect(p->pWin);
+    }
+#endif
+    if( bFree ) sqlite3DbNNFreeNN(db, p);
+    p = pPrior;
+    bFree = 1;
+  }
+}
+
+/*
+** Initialize a SelectDest structure.
+*/
+SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
+  pDest->eDest = (u8)eDest;
+  pDest->iSDParm = iParm;
+  pDest->iSDParm2 = 0;
+  pDest->zAffSdst = 0;
+  pDest->iSdst = 0;
+  pDest->nSdst = 0;
+}
+
+
+/*
+** Allocate a new Select structure and return a pointer to that
+** structure.
+*/
+SQLITE_PRIVATE Select *sqlite3SelectNew(
+  Parse *pParse,        /* Parsing context */
+  ExprList *pEList,     /* which columns to include in the result */
+  SrcList *pSrc,        /* the FROM clause -- which tables to scan */
+  Expr *pWhere,         /* the WHERE clause */
+  ExprList *pGroupBy,   /* the GROUP BY clause */
+  Expr *pHaving,        /* the HAVING clause */
+  ExprList *pOrderBy,   /* the ORDER BY clause */
+  u32 selFlags,         /* Flag parameters, such as SF_Distinct */
+  Expr *pLimit          /* LIMIT value.  NULL means not used */
+){
+  Select *pNew, *pAllocated;
+  Select standin;
+  pAllocated = pNew = sqlite3DbMallocRawNN(pParse->db, sizeof(*pNew) );
+  if( pNew==0 ){
+    assert( pParse->db->mallocFailed );
+    pNew = &standin;
+  }
+  if( pEList==0 ){
+    pEList = sqlite3ExprListAppend(pParse, 0,
+                                   sqlite3Expr(pParse->db,TK_ASTERISK,0));
+  }
+  pNew->pEList = pEList;
+  pNew->op = TK_SELECT;
+  pNew->selFlags = selFlags;
+  pNew->iLimit = 0;
+  pNew->iOffset = 0;
+  pNew->selId = ++pParse->nSelect;
+  pNew->addrOpenEphm[0] = -1;
+  pNew->addrOpenEphm[1] = -1;
+  pNew->nSelectRow = 0;
+  if( pSrc==0 ) pSrc = sqlite3DbMallocZero(pParse->db, sizeof(*pSrc));
+  pNew->pSrc = pSrc;
+  pNew->pWhere = pWhere;
+  pNew->pGroupBy = pGroupBy;
+  pNew->pHaving = pHaving;
+  pNew->pOrderBy = pOrderBy;
+  pNew->pPrior = 0;
+  pNew->pNext = 0;
+  pNew->pLimit = pLimit;
+  pNew->pWith = 0;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  pNew->pWin = 0;
+  pNew->pWinDefn = 0;
+#endif
+  if( pParse->db->mallocFailed ) {
+    clearSelect(pParse->db, pNew, pNew!=&standin);
+    pAllocated = 0;
+  }else{
+    assert( pNew->pSrc!=0 || pParse->nErr>0 );
+  }
+  return pAllocated;
+}
+
+
+/*
+** Delete the given Select structure and all of its substructures.
+*/
+SQLITE_PRIVATE void sqlite3SelectDelete(sqlite3 *db, Select *p){
+  if( OK_IF_ALWAYS_TRUE(p) ) clearSelect(db, p, 1);
+}
+SQLITE_PRIVATE void sqlite3SelectDeleteGeneric(sqlite3 *db, void *p){
+  if( ALWAYS(p) ) clearSelect(db, (Select*)p, 1);
+}
+
+/*
+** Return a pointer to the right-most SELECT statement in a compound.
+*/
+static Select *findRightmost(Select *p){
+  while( p->pNext ) p = p->pNext;
+  return p;
+}
+
+/*
+** Given 1 to 3 identifiers preceding the JOIN keyword, determine the
+** type of join.  Return an integer constant that expresses that type
+** in terms of the following bit values:
+**
+**     JT_INNER
+**     JT_CROSS
+**     JT_OUTER
+**     JT_NATURAL
+**     JT_LEFT
+**     JT_RIGHT
+**
+** A full outer join is the combination of JT_LEFT and JT_RIGHT.
+**
+** If an illegal or unsupported join type is seen, then still return
+** a join type, but put an error in the pParse structure.
+**
+** These are the valid join types:
+**
+**
+**      pA       pB       pC               Return Value
+**     -------  -----    -----             ------------
+**     CROSS      -        -                 JT_CROSS
+**     INNER      -        -                 JT_INNER
+**     LEFT       -        -                 JT_LEFT|JT_OUTER
+**     LEFT     OUTER      -                 JT_LEFT|JT_OUTER
+**     RIGHT      -        -                 JT_RIGHT|JT_OUTER
+**     RIGHT    OUTER      -                 JT_RIGHT|JT_OUTER
+**     FULL       -        -                 JT_LEFT|JT_RIGHT|JT_OUTER
+**     FULL     OUTER      -                 JT_LEFT|JT_RIGHT|JT_OUTER
+**     NATURAL  INNER      -                 JT_NATURAL|JT_INNER
+**     NATURAL  LEFT       -                 JT_NATURAL|JT_LEFT|JT_OUTER
+**     NATURAL  LEFT     OUTER               JT_NATURAL|JT_LEFT|JT_OUTER
+**     NATURAL  RIGHT      -                 JT_NATURAL|JT_RIGHT|JT_OUTER
+**     NATURAL  RIGHT    OUTER               JT_NATURAL|JT_RIGHT|JT_OUTER
+**     NATURAL  FULL       -                 JT_NATURAL|JT_LEFT|JT_RIGHT
+**     NATURAL  FULL     OUTER               JT_NATRUAL|JT_LEFT|JT_RIGHT
+**
+** To preserve historical compatibly, SQLite also accepts a variety
+** of other non-standard and in many cases nonsensical join types.
+** This routine makes as much sense at it can from the nonsense join
+** type and returns a result.  Examples of accepted nonsense join types
+** include but are not limited to:
+**
+**          INNER CROSS JOIN        ->   same as JOIN
+**          NATURAL CROSS JOIN      ->   same as NATURAL JOIN
+**          OUTER LEFT JOIN         ->   same as LEFT JOIN
+**          LEFT NATURAL JOIN       ->   same as NATURAL LEFT JOIN
+**          LEFT RIGHT JOIN         ->   same as FULL JOIN
+**          RIGHT OUTER FULL JOIN   ->   same as FULL JOIN
+**          CROSS CROSS CROSS JOIN  ->   same as JOIN
+**
+** The only restrictions on the join type name are:
+**
+**    *   "INNER" cannot appear together with "OUTER", "LEFT", "RIGHT",
+**        or "FULL".
+**
+**    *   "CROSS" cannot appear together with "OUTER", "LEFT", "RIGHT,
+**        or "FULL".
+**
+**    *   If "OUTER" is present then there must also be one of
+**        "LEFT", "RIGHT", or "FULL"
+*/
+SQLITE_PRIVATE int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
+  int jointype = 0;
+  Token *apAll[3];
+  Token *p;
+                             /*   0123456789 123456789 123456789 123 */
+  static const char zKeyText[] = "naturaleftouterightfullinnercross";
+  static const struct {
+    u8 i;        /* Beginning of keyword text in zKeyText[] */
+    u8 nChar;    /* Length of the keyword in characters */
+    u8 code;     /* Join type mask */
+  } aKeyword[] = {
+    /* (0) natural */ { 0,  7, JT_NATURAL                },
+    /* (1) left    */ { 6,  4, JT_LEFT|JT_OUTER          },
+    /* (2) outer   */ { 10, 5, JT_OUTER                  },
+    /* (3) right   */ { 14, 5, JT_RIGHT|JT_OUTER         },
+    /* (4) full    */ { 19, 4, JT_LEFT|JT_RIGHT|JT_OUTER },
+    /* (5) inner   */ { 23, 5, JT_INNER                  },
+    /* (6) cross   */ { 28, 5, JT_INNER|JT_CROSS         },
+  };
+  int i, j;
+  apAll[0] = pA;
+  apAll[1] = pB;
+  apAll[2] = pC;
+  for(i=0; i<3 && apAll[i]; i++){
+    p = apAll[i];
+    for(j=0; j<ArraySize(aKeyword); j++){
+      if( p->n==aKeyword[j].nChar
+          && sqlite3StrNICmp((char*)p->z, &zKeyText[aKeyword[j].i], p->n)==0 ){
+        jointype |= aKeyword[j].code;
+        break;
+      }
+    }
+    testcase( j==0 || j==1 || j==2 || j==3 || j==4 || j==5 || j==6 );
+    if( j>=ArraySize(aKeyword) ){
+      jointype |= JT_ERROR;
+      break;
+    }
+  }
+  if(
+     (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
+     (jointype & JT_ERROR)!=0 ||
+     (jointype & (JT_OUTER|JT_LEFT|JT_RIGHT))==JT_OUTER
+  ){
+    const char *zSp1 = " ";
+    const char *zSp2 = " ";
+    if( pB==0 ){ zSp1++; }
+    if( pC==0 ){ zSp2++; }
+    sqlite3ErrorMsg(pParse, "unknown join type: "
+       "%T%s%T%s%T", pA, zSp1, pB, zSp2, pC);
+    jointype = JT_INNER;
+  }
+  return jointype;
+}
+
+/*
+** Return the index of a column in a table.  Return -1 if the column
+** is not contained in the table.
+*/
+SQLITE_PRIVATE int sqlite3ColumnIndex(Table *pTab, const char *zCol){
+  int i;
+  u8 h = sqlite3StrIHash(zCol);
+  Column *pCol;
+  for(pCol=pTab->aCol, i=0; i<pTab->nCol; pCol++, i++){
+    if( pCol->hName==h && sqlite3StrICmp(pCol->zCnName, zCol)==0 ) return i;
+  }
+  return -1;
+}
+
+/*
+** Mark a subquery result column as having been used.
+*/
+SQLITE_PRIVATE void sqlite3SrcItemColumnUsed(SrcItem *pItem, int iCol){
+  assert( pItem!=0 );
+  assert( (int)pItem->fg.isNestedFrom == IsNestedFrom(pItem) );
+  if( pItem->fg.isNestedFrom ){
+    ExprList *pResults;
+    assert( pItem->fg.isSubquery );
+    assert( pItem->u4.pSubq!=0 );
+    assert( pItem->u4.pSubq->pSelect!=0 );
+    pResults = pItem->u4.pSubq->pSelect->pEList;
+    assert( pResults!=0 );
+    assert( iCol>=0 && iCol<pResults->nExpr );
+    pResults->a[iCol].fg.bUsed = 1;
+  }
+}
+
+/*
+** Search the tables iStart..iEnd (inclusive) in pSrc, looking for a
+** table that has a column named zCol.  The search is left-to-right.
+** The first match found is returned.
+**
+** When found, set *piTab and *piCol to the table index and column index
+** of the matching column and return TRUE.
+**
+** If not found, return FALSE.
+*/
+static int tableAndColumnIndex(
+  SrcList *pSrc,       /* Array of tables to search */
+  int iStart,          /* First member of pSrc->a[] to check */
+  int iEnd,            /* Last member of pSrc->a[] to check */
+  const char *zCol,    /* Name of the column we are looking for */
+  int *piTab,          /* Write index of pSrc->a[] here */
+  int *piCol,          /* Write index of pSrc->a[*piTab].pTab->aCol[] here */
+  int bIgnoreHidden    /* Ignore hidden columns */
+){
+  int i;               /* For looping over tables in pSrc */
+  int iCol;            /* Index of column matching zCol */
+
+  assert( iEnd<pSrc->nSrc );
+  assert( iStart>=0 );
+  assert( (piTab==0)==(piCol==0) );  /* Both or neither are NULL */
+
+  for(i=iStart; i<=iEnd; i++){
+    iCol = sqlite3ColumnIndex(pSrc->a[i].pSTab, zCol);
+    if( iCol>=0
+     && (bIgnoreHidden==0 || IsHiddenColumn(&pSrc->a[i].pSTab->aCol[iCol])==0)
+    ){
+      if( piTab ){
+        sqlite3SrcItemColumnUsed(&pSrc->a[i], iCol);
+        *piTab = i;
+        *piCol = iCol;
+      }
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Set the EP_OuterON property on all terms of the given expression.
+** And set the Expr.w.iJoin to iTable for every term in the
+** expression.
+**
+** The EP_OuterON property is used on terms of an expression to tell
+** the OUTER JOIN processing logic that this term is part of the
+** join restriction specified in the ON or USING clause and not a part
+** of the more general WHERE clause.  These terms are moved over to the
+** WHERE clause during join processing but we need to remember that they
+** originated in the ON or USING clause.
+**
+** The Expr.w.iJoin tells the WHERE clause processing that the
+** expression depends on table w.iJoin even if that table is not
+** explicitly mentioned in the expression.  That information is needed
+** for cases like this:
+**
+**    SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
+**
+** The where clause needs to defer the handling of the t1.x=5
+** term until after the t2 loop of the join.  In that way, a
+** NULL t2 row will be inserted whenever t1.x!=5.  If we do not
+** defer the handling of t1.x=5, it will be processed immediately
+** after the t1 loop and rows with t1.x!=5 will never appear in
+** the output, which is incorrect.
+*/
+SQLITE_PRIVATE void sqlite3SetJoinExpr(Expr *p, int iTable, u32 joinFlag){
+  assert( joinFlag==EP_OuterON || joinFlag==EP_InnerON );
+  while( p ){
+    ExprSetProperty(p, joinFlag);
+    assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
+    ExprSetVVAProperty(p, EP_NoReduce);
+    p->w.iJoin = iTable;
+    if( p->op==TK_FUNCTION ){
+      assert( ExprUseXList(p) );
+      if( p->x.pList ){
+        int i;
+        for(i=0; i<p->x.pList->nExpr; i++){
+          sqlite3SetJoinExpr(p->x.pList->a[i].pExpr, iTable, joinFlag);
+        }
+      }
+    }
+    sqlite3SetJoinExpr(p->pLeft, iTable, joinFlag);
+    p = p->pRight;
+  }
+}
+
+/* Undo the work of sqlite3SetJoinExpr().  This is used when a LEFT JOIN
+** is simplified into an ordinary JOIN, and when an ON expression is
+** "pushed down" into the WHERE clause of a subquery.
+**
+** Convert every term that is marked with EP_OuterON and w.iJoin==iTable into
+** an ordinary term that omits the EP_OuterON mark.  Or if iTable<0, then
+** just clear every EP_OuterON and EP_InnerON mark from the expression tree.
+**
+** If nullable is true, that means that Expr p might evaluate to NULL even
+** if it is a reference to a NOT NULL column.  This can happen, for example,
+** if the table that p references is on the left side of a RIGHT JOIN.
+** If nullable is true, then take care to not remove the EP_CanBeNull bit.
+** See forum thread https://sqlite.org/forum/forumpost/b40696f50145d21c
+*/
+static void unsetJoinExpr(Expr *p, int iTable, int nullable){
+  while( p ){
+    if( iTable<0 || (ExprHasProperty(p, EP_OuterON) && p->w.iJoin==iTable) ){
+      ExprClearProperty(p, EP_OuterON|EP_InnerON);
+      if( iTable>=0 ) ExprSetProperty(p, EP_InnerON);
+    }
+    if( p->op==TK_COLUMN && p->iTable==iTable && !nullable ){
+      ExprClearProperty(p, EP_CanBeNull);
+    }
+    if( p->op==TK_FUNCTION ){
+      assert( ExprUseXList(p) );
+      assert( p->pLeft==0 );
+      if( p->x.pList ){
+        int i;
+        for(i=0; i<p->x.pList->nExpr; i++){
+          unsetJoinExpr(p->x.pList->a[i].pExpr, iTable, nullable);
+        }
+      }
+    }
+    unsetJoinExpr(p->pLeft, iTable, nullable);
+    p = p->pRight;
+  }
+}
+
+/*
+** This routine processes the join information for a SELECT statement.
+**
+**   *  A NATURAL join is converted into a USING join.  After that, we
+**      do not need to be concerned with NATURAL joins and we only have
+**      think about USING joins.
+**
+**   *  ON and USING clauses result in extra terms being added to the
+**      WHERE clause to enforce the specified constraints.  The extra
+**      WHERE clause terms will be tagged with EP_OuterON or
+**      EP_InnerON so that we know that they originated in ON/USING.
+**
+** The terms of a FROM clause are contained in the Select.pSrc structure.
+** The left most table is the first entry in Select.pSrc.  The right-most
+** table is the last entry.  The join operator is held in the entry to
+** the right.  Thus entry 1 contains the join operator for the join between
+** entries 0 and 1.  Any ON or USING clauses associated with the join are
+** also attached to the right entry.
+**
+** This routine returns the number of errors encountered.
+*/
+static int sqlite3ProcessJoin(Parse *pParse, Select *p){
+  SrcList *pSrc;                  /* All tables in the FROM clause */
+  int i, j;                       /* Loop counters */
+  SrcItem *pLeft;                 /* Left table being joined */
+  SrcItem *pRight;                /* Right table being joined */
+
+  pSrc = p->pSrc;
+  pLeft = &pSrc->a[0];
+  pRight = &pLeft[1];
+  for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
+    Table *pRightTab = pRight->pSTab;
+    u32 joinType;
+
+    if( NEVER(pLeft->pSTab==0 || pRightTab==0) ) continue;
+    joinType = (pRight->fg.jointype & JT_OUTER)!=0 ? EP_OuterON : EP_InnerON;
+
+    /* If this is a NATURAL join, synthesize an appropriate USING clause
+    ** to specify which columns should be joined.
+    */
+    if( pRight->fg.jointype & JT_NATURAL ){
+      IdList *pUsing = 0;
+      if( pRight->fg.isUsing || pRight->u3.pOn ){
+        sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
+           "an ON or USING clause", 0);
+        return 1;
+      }
+      for(j=0; j<pRightTab->nCol; j++){
+        char *zName;   /* Name of column in the right table */
+
+        if( IsHiddenColumn(&pRightTab->aCol[j]) ) continue;
+        zName = pRightTab->aCol[j].zCnName;
+        if( tableAndColumnIndex(pSrc, 0, i, zName, 0, 0, 1) ){
+          pUsing = sqlite3IdListAppend(pParse, pUsing, 0);
+          if( pUsing ){
+            assert( pUsing->nId>0 );
+            assert( pUsing->a[pUsing->nId-1].zName==0 );
+            pUsing->a[pUsing->nId-1].zName = sqlite3DbStrDup(pParse->db, zName);
+          }
+        }
+      }
+      if( pUsing ){
+        pRight->fg.isUsing = 1;
+        pRight->fg.isSynthUsing = 1;
+        pRight->u3.pUsing = pUsing;
+      }
+      if( pParse->nErr ) return 1;
+    }
+
+    /* Create extra terms on the WHERE clause for each column named
+    ** in the USING clause.  Example: If the two tables to be joined are
+    ** A and B and the USING clause names X, Y, and Z, then add this
+    ** to the WHERE clause:    A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
+    ** Report an error if any column mentioned in the USING clause is
+    ** not contained in both tables to be joined.
+    */
+    if( pRight->fg.isUsing ){
+      IdList *pList = pRight->u3.pUsing;
+      sqlite3 *db = pParse->db;
+      assert( pList!=0 );
+      for(j=0; j<pList->nId; j++){
+        char *zName;     /* Name of the term in the USING clause */
+        int iLeft;       /* Table on the left with matching column name */
+        int iLeftCol;    /* Column number of matching column on the left */
+        int iRightCol;   /* Column number of matching column on the right */
+        Expr *pE1;       /* Reference to the column on the LEFT of the join */
+        Expr *pE2;       /* Reference to the column on the RIGHT of the join */
+        Expr *pEq;       /* Equality constraint.  pE1 == pE2 */
+
+        zName = pList->a[j].zName;
+        iRightCol = sqlite3ColumnIndex(pRightTab, zName);
+        if( iRightCol<0
+         || tableAndColumnIndex(pSrc, 0, i, zName, &iLeft, &iLeftCol,
+                                pRight->fg.isSynthUsing)==0
+        ){
+          sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
+            "not present in both tables", zName);
+          return 1;
+        }
+        pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol);
+        sqlite3SrcItemColumnUsed(&pSrc->a[iLeft], iLeftCol);
+        if( (pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
+          /* This branch runs if the query contains one or more RIGHT or FULL
+          ** JOINs.  If only a single table on the left side of this join
+          ** contains the zName column, then this branch is a no-op.
+          ** But if there are two or more tables on the left side
+          ** of the join, construct a coalesce() function that gathers all
+          ** such tables.  Raise an error if more than one of those references
+          ** to zName is not also within a prior USING clause.
+          **
+          ** We really ought to raise an error if there are two or more
+          ** non-USING references to zName on the left of an INNER or LEFT
+          ** JOIN.  But older versions of SQLite do not do that, so we avoid
+          ** adding a new error so as to not break legacy applications.
+          */
+          ExprList *pFuncArgs = 0;   /* Arguments to the coalesce() */
+          static const Token tkCoalesce = { "coalesce", 8 };
+          while( tableAndColumnIndex(pSrc, iLeft+1, i, zName, &iLeft, &iLeftCol,
+                                     pRight->fg.isSynthUsing)!=0 ){
+            if( pSrc->a[iLeft].fg.isUsing==0
+             || sqlite3IdListIndex(pSrc->a[iLeft].u3.pUsing, zName)<0
+            ){
+              sqlite3ErrorMsg(pParse, "ambiguous reference to %s in USING()",
+                              zName);
+              break;
+            }
+            pFuncArgs = sqlite3ExprListAppend(pParse, pFuncArgs, pE1);
+            pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol);
+            sqlite3SrcItemColumnUsed(&pSrc->a[iLeft], iLeftCol);
+          }
+          if( pFuncArgs ){
+            pFuncArgs = sqlite3ExprListAppend(pParse, pFuncArgs, pE1);
+            pE1 = sqlite3ExprFunction(pParse, pFuncArgs, &tkCoalesce, 0);
+          }
+        }
+        pE2 = sqlite3CreateColumnExpr(db, pSrc, i+1, iRightCol);
+        sqlite3SrcItemColumnUsed(pRight, iRightCol);
+        pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2);
+        assert( pE2!=0 || pEq==0 );
+        if( pEq ){
+          ExprSetProperty(pEq, joinType);
+          assert( !ExprHasProperty(pEq, EP_TokenOnly|EP_Reduced) );
+          ExprSetVVAProperty(pEq, EP_NoReduce);
+          pEq->w.iJoin = pE2->iTable;
+        }
+        p->pWhere = sqlite3ExprAnd(pParse, p->pWhere, pEq);
+      }
+    }
+
+    /* Add the ON clause to the end of the WHERE clause, connected by
+    ** an AND operator.
+    */
+    else if( pRight->u3.pOn ){
+      sqlite3SetJoinExpr(pRight->u3.pOn, pRight->iCursor, joinType);
+      p->pWhere = sqlite3ExprAnd(pParse, p->pWhere, pRight->u3.pOn);
+      pRight->u3.pOn = 0;
+      pRight->fg.isOn = 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** An instance of this object holds information (beyond pParse and pSelect)
+** needed to load the next result row that is to be added to the sorter.
+*/
+typedef struct RowLoadInfo RowLoadInfo;
+struct RowLoadInfo {
+  int regResult;               /* Store results in array of registers here */
+  u8 ecelFlags;                /* Flag argument to ExprCodeExprList() */
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  ExprList *pExtra;            /* Extra columns needed by sorter refs */
+  int regExtraResult;          /* Where to load the extra columns */
+#endif
+};
+
+/*
+** This routine does the work of loading query data into an array of
+** registers so that it can be added to the sorter.
+*/
+static void innerLoopLoadRow(
+  Parse *pParse,             /* Statement under construction */
+  Select *pSelect,           /* The query being coded */
+  RowLoadInfo *pInfo         /* Info needed to complete the row load */
+){
+  sqlite3ExprCodeExprList(pParse, pSelect->pEList, pInfo->regResult,
+                          0, pInfo->ecelFlags);
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  if( pInfo->pExtra ){
+    sqlite3ExprCodeExprList(pParse, pInfo->pExtra, pInfo->regExtraResult, 0, 0);
+    sqlite3ExprListDelete(pParse->db, pInfo->pExtra);
+  }
+#endif
+}
+
+/*
+** Code the OP_MakeRecord instruction that generates the entry to be
+** added into the sorter.
+**
+** Return the register in which the result is stored.
+*/
+static int makeSorterRecord(
+  Parse *pParse,
+  SortCtx *pSort,
+  Select *pSelect,
+  int regBase,
+  int nBase
+){
+  int nOBSat = pSort->nOBSat;
+  Vdbe *v = pParse->pVdbe;
+  int regOut = ++pParse->nMem;
+  if( pSort->pDeferredRowLoad ){
+    innerLoopLoadRow(pParse, pSelect, pSort->pDeferredRowLoad);
+  }
+  sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase+nOBSat, nBase-nOBSat, regOut);
+  return regOut;
+}
+
+/*
+** Generate code that will push the record in registers regData
+** through regData+nData-1 onto the sorter.
+*/
+static void pushOntoSorter(
+  Parse *pParse,         /* Parser context */
+  SortCtx *pSort,        /* Information about the ORDER BY clause */
+  Select *pSelect,       /* The whole SELECT statement */
+  int regData,           /* First register holding data to be sorted */
+  int regOrigData,       /* First register holding data before packing */
+  int nData,             /* Number of elements in the regData data array */
+  int nPrefixReg         /* No. of reg prior to regData available for use */
+){
+  Vdbe *v = pParse->pVdbe;                         /* Stmt under construction */
+  int bSeq = ((pSort->sortFlags & SORTFLAG_UseSorter)==0);
+  int nExpr = pSort->pOrderBy->nExpr;              /* No. of ORDER BY terms */
+  int nBase = nExpr + bSeq + nData;                /* Fields in sorter record */
+  int regBase;                                     /* Regs for sorter record */
+  int regRecord = 0;                               /* Assembled sorter record */
+  int nOBSat = pSort->nOBSat;                      /* ORDER BY terms to skip */
+  int op;                            /* Opcode to add sorter record to sorter */
+  int iLimit;                        /* LIMIT counter */
+  int iSkip = 0;                     /* End of the sorter insert loop */
+
+  assert( bSeq==0 || bSeq==1 );
+
+  /* Three cases:
+  **   (1) The data to be sorted has already been packed into a Record
+  **       by a prior OP_MakeRecord.  In this case nData==1 and regData
+  **       will be completely unrelated to regOrigData.
+  **   (2) All output columns are included in the sort record.  In that
+  **       case regData==regOrigData.
+  **   (3) Some output columns are omitted from the sort record due to
+  **       the SQLITE_ENABLE_SORTER_REFERENCES optimization, or due to the
+  **       SQLITE_ECEL_OMITREF optimization, or due to the
+  **       SortCtx.pDeferredRowLoad optimization.  In any of these cases
+  **       regOrigData is 0 to prevent this routine from trying to copy
+  **       values that might not yet exist.
+  */
+  assert( nData==1 || regData==regOrigData || regOrigData==0 );
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  pSort->addrPush = sqlite3VdbeCurrentAddr(v);
+#endif
+
+  if( nPrefixReg ){
+    assert( nPrefixReg==nExpr+bSeq );
+    regBase = regData - nPrefixReg;
+  }else{
+    regBase = pParse->nMem + 1;
+    pParse->nMem += nBase;
+  }
+  assert( pSelect->iOffset==0 || pSelect->iLimit!=0 );
+  iLimit = pSelect->iOffset ? pSelect->iOffset+1 : pSelect->iLimit;
+  pSort->labelDone = sqlite3VdbeMakeLabel(pParse);
+  sqlite3ExprCodeExprList(pParse, pSort->pOrderBy, regBase, regOrigData,
+                          SQLITE_ECEL_DUP | (regOrigData? SQLITE_ECEL_REF : 0));
+  if( bSeq ){
+    sqlite3VdbeAddOp2(v, OP_Sequence, pSort->iECursor, regBase+nExpr);
+  }
+  if( nPrefixReg==0 && nData>0 ){
+    sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+bSeq, nData);
+  }
+  if( nOBSat>0 ){
+    int regPrevKey;   /* The first nOBSat columns of the previous row */
+    int addrFirst;    /* Address of the OP_IfNot opcode */
+    int addrJmp;      /* Address of the OP_Jump opcode */
+    VdbeOp *pOp;      /* Opcode that opens the sorter */
+    int nKey;         /* Number of sorting key columns, including OP_Sequence */
+    KeyInfo *pKI;     /* Original KeyInfo on the sorter table */
+
+    regRecord = makeSorterRecord(pParse, pSort, pSelect, regBase, nBase);
+    regPrevKey = pParse->nMem+1;
+    pParse->nMem += pSort->nOBSat;
+    nKey = nExpr - pSort->nOBSat + bSeq;
+    if( bSeq ){
+      addrFirst = sqlite3VdbeAddOp1(v, OP_IfNot, regBase+nExpr);
+    }else{
+      addrFirst = sqlite3VdbeAddOp1(v, OP_SequenceTest, pSort->iECursor);
+    }
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp3(v, OP_Compare, regPrevKey, regBase, pSort->nOBSat);
+    pOp = sqlite3VdbeGetOp(v, pSort->addrSortIndex);
+    if( pParse->db->mallocFailed ) return;
+    pOp->p2 = nKey + nData;
+    pKI = pOp->p4.pKeyInfo;
+    memset(pKI->aSortFlags, 0, pKI->nKeyField); /* Makes OP_Jump testable */
+    sqlite3VdbeChangeP4(v, -1, (char*)pKI, P4_KEYINFO);
+    testcase( pKI->nAllField > pKI->nKeyField+2 );
+    pOp->p4.pKeyInfo = sqlite3KeyInfoFromExprList(pParse,pSort->pOrderBy,nOBSat,
+                                           pKI->nAllField-pKI->nKeyField-1);
+    pOp = 0; /* Ensure pOp not used after sqlite3VdbeAddOp3() */
+    addrJmp = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeAddOp3(v, OP_Jump, addrJmp+1, 0, addrJmp+1); VdbeCoverage(v);
+    pSort->labelBkOut = sqlite3VdbeMakeLabel(pParse);
+    pSort->regReturn = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Gosub, pSort->regReturn, pSort->labelBkOut);
+    sqlite3VdbeAddOp1(v, OP_ResetSorter, pSort->iECursor);
+    if( iLimit ){
+      sqlite3VdbeAddOp2(v, OP_IfNot, iLimit, pSort->labelDone);
+      VdbeCoverage(v);
+    }
+    sqlite3VdbeJumpHere(v, addrFirst);
+    sqlite3ExprCodeMove(pParse, regBase, regPrevKey, pSort->nOBSat);
+    sqlite3VdbeJumpHere(v, addrJmp);
+  }
+  if( iLimit ){
+    /* At this point the values for the new sorter entry are stored
+    ** in an array of registers. They need to be composed into a record
+    ** and inserted into the sorter if either (a) there are currently
+    ** less than LIMIT+OFFSET items or (b) the new record is smaller than
+    ** the largest record currently in the sorter. If (b) is true and there
+    ** are already LIMIT+OFFSET items in the sorter, delete the largest
+    ** entry before inserting the new one. This way there are never more
+    ** than LIMIT+OFFSET items in the sorter.
+    **
+    ** If the new record does not need to be inserted into the sorter,
+    ** jump to the next iteration of the loop. If the pSort->labelOBLopt
+    ** value is not zero, then it is a label of where to jump.  Otherwise,
+    ** just bypass the row insert logic.  See the header comment on the
+    ** sqlite3WhereOrderByLimitOptLabel() function for additional info.
+    */
+    int iCsr = pSort->iECursor;
+    sqlite3VdbeAddOp2(v, OP_IfNotZero, iLimit, sqlite3VdbeCurrentAddr(v)+4);
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp2(v, OP_Last, iCsr, 0);
+    iSkip = sqlite3VdbeAddOp4Int(v, OP_IdxLE,
+                                 iCsr, 0, regBase+nOBSat, nExpr-nOBSat);
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp1(v, OP_Delete, iCsr);
+  }
+  if( regRecord==0 ){
+    regRecord = makeSorterRecord(pParse, pSort, pSelect, regBase, nBase);
+  }
+  if( pSort->sortFlags & SORTFLAG_UseSorter ){
+    op = OP_SorterInsert;
+  }else{
+    op = OP_IdxInsert;
+  }
+  sqlite3VdbeAddOp4Int(v, op, pSort->iECursor, regRecord,
+                       regBase+nOBSat, nBase-nOBSat);
+  if( iSkip ){
+    sqlite3VdbeChangeP2(v, iSkip,
+         pSort->labelOBLopt ? pSort->labelOBLopt : sqlite3VdbeCurrentAddr(v));
+  }
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  pSort->addrPushEnd = sqlite3VdbeCurrentAddr(v)-1;
+#endif
+}
+
+/*
+** Add code to implement the OFFSET
+*/
+static void codeOffset(
+  Vdbe *v,          /* Generate code into this VM */
+  int iOffset,      /* Register holding the offset counter */
+  int iContinue     /* Jump here to skip the current record */
+){
+  if( iOffset>0 ){
+    sqlite3VdbeAddOp3(v, OP_IfPos, iOffset, iContinue, 1); VdbeCoverage(v);
+    VdbeComment((v, "OFFSET"));
+  }
+}
+
+/*
+** Add code that will check to make sure the array of registers starting at
+** iMem form a distinct entry. This is used by both "SELECT DISTINCT ..." and
+** distinct aggregates ("SELECT count(DISTINCT <expr>) ..."). Three strategies
+** are available. Which is used depends on the value of parameter eTnctType,
+** as follows:
+**
+**   WHERE_DISTINCT_UNORDERED/WHERE_DISTINCT_NOOP:
+**     Build an ephemeral table that contains all entries seen before and
+**     skip entries which have been seen before.
+**
+**     Parameter iTab is the cursor number of an ephemeral table that must
+**     be opened before the VM code generated by this routine is executed.
+**     The ephemeral cursor table is queried for a record identical to the
+**     record formed by the current array of registers. If one is found,
+**     jump to VM address addrRepeat. Otherwise, insert a new record into
+**     the ephemeral cursor and proceed.
+**
+**     The returned value in this case is a copy of parameter iTab.
+**
+**   WHERE_DISTINCT_ORDERED:
+**     In this case rows are being delivered sorted order. The ephemeral
+**     table is not required. Instead, the current set of values
+**     is compared against previous row. If they match, the new row
+**     is not distinct and control jumps to VM address addrRepeat. Otherwise,
+**     the VM program proceeds with processing the new row.
+**
+**     The returned value in this case is the register number of the first
+**     in an array of registers used to store the previous result row so that
+**     it can be compared to the next. The caller must ensure that this
+**     register is initialized to NULL.  (The fixDistinctOpenEph() routine
+**     will take care of this initialization.)
+**
+**   WHERE_DISTINCT_UNIQUE:
+**     In this case it has already been determined that the rows are distinct.
+**     No special action is required. The return value is zero.
+**
+** Parameter pEList is the list of expressions used to generated the
+** contents of each row. It is used by this routine to determine (a)
+** how many elements there are in the array of registers and (b) the
+** collation sequences that should be used for the comparisons if
+** eTnctType is WHERE_DISTINCT_ORDERED.
+*/
+static int codeDistinct(
+  Parse *pParse,     /* Parsing and code generating context */
+  int eTnctType,     /* WHERE_DISTINCT_* value */
+  int iTab,          /* A sorting index used to test for distinctness */
+  int addrRepeat,    /* Jump to here if not distinct */
+  ExprList *pEList,  /* Expression for each element */
+  int regElem        /* First element */
+){
+  int iRet = 0;
+  int nResultCol = pEList->nExpr;
+  Vdbe *v = pParse->pVdbe;
+
+  switch( eTnctType ){
+    case WHERE_DISTINCT_ORDERED: {
+      int i;
+      int iJump;              /* Jump destination */
+      int regPrev;            /* Previous row content */
+
+      /* Allocate space for the previous row */
+      iRet = regPrev = pParse->nMem+1;
+      pParse->nMem += nResultCol;
+
+      iJump = sqlite3VdbeCurrentAddr(v) + nResultCol;
+      for(i=0; i<nResultCol; i++){
+        CollSeq *pColl = sqlite3ExprCollSeq(pParse, pEList->a[i].pExpr);
+        if( i<nResultCol-1 ){
+          sqlite3VdbeAddOp3(v, OP_Ne, regElem+i, iJump, regPrev+i);
+          VdbeCoverage(v);
+        }else{
+          sqlite3VdbeAddOp3(v, OP_Eq, regElem+i, addrRepeat, regPrev+i);
+          VdbeCoverage(v);
+         }
+        sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
+        sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
+      }
+      assert( sqlite3VdbeCurrentAddr(v)==iJump || pParse->db->mallocFailed );
+      sqlite3VdbeAddOp3(v, OP_Copy, regElem, regPrev, nResultCol-1);
+      break;
+    }
+
+    case WHERE_DISTINCT_UNIQUE: {
+      /* nothing to do */
+      break;
+    }
+
+    default: {
+      int r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp4Int(v, OP_Found, iTab, addrRepeat, regElem, nResultCol);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regElem, nResultCol, r1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iTab, r1, regElem, nResultCol);
+      sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+      sqlite3ReleaseTempReg(pParse, r1);
+      iRet = iTab;
+      break;
+    }
+  }
+
+  return iRet;
+}
+
+/*
+** This routine runs after codeDistinct().  It makes necessary
+** adjustments to the OP_OpenEphemeral opcode that the codeDistinct()
+** routine made use of.  This processing must be done separately since
+** sometimes codeDistinct is called before the OP_OpenEphemeral is actually
+** laid down.
+**
+** WHERE_DISTINCT_NOOP:
+** WHERE_DISTINCT_UNORDERED:
+**
+**     No adjustments necessary.  This function is a no-op.
+**
+** WHERE_DISTINCT_UNIQUE:
+**
+**     The ephemeral table is not needed.  So change the
+**     OP_OpenEphemeral opcode into an OP_Noop.
+**
+** WHERE_DISTINCT_ORDERED:
+**
+**     The ephemeral table is not needed.  But we do need register
+**     iVal to be initialized to NULL.  So change the OP_OpenEphemeral
+**     into an OP_Null on the iVal register.
+*/
+static void fixDistinctOpenEph(
+  Parse *pParse,     /* Parsing and code generating context */
+  int eTnctType,     /* WHERE_DISTINCT_* value */
+  int iVal,          /* Value returned by codeDistinct() */
+  int iOpenEphAddr   /* Address of OP_OpenEphemeral instruction for iTab */
+){
+  if( pParse->nErr==0
+   && (eTnctType==WHERE_DISTINCT_UNIQUE || eTnctType==WHERE_DISTINCT_ORDERED)
+  ){
+    Vdbe *v = pParse->pVdbe;
+    sqlite3VdbeChangeToNoop(v, iOpenEphAddr);
+    if( sqlite3VdbeGetOp(v, iOpenEphAddr+1)->opcode==OP_Explain ){
+      sqlite3VdbeChangeToNoop(v, iOpenEphAddr+1);
+    }
+    if( eTnctType==WHERE_DISTINCT_ORDERED ){
+      /* Change the OP_OpenEphemeral to an OP_Null that sets the MEM_Cleared
+      ** bit on the first register of the previous value.  This will cause the
+      ** OP_Ne added in codeDistinct() to always fail on the first iteration of
+      ** the loop even if the first row is all NULLs.  */
+      VdbeOp *pOp = sqlite3VdbeGetOp(v, iOpenEphAddr);
+      pOp->opcode = OP_Null;
+      pOp->p1 = 1;
+      pOp->p2 = iVal;
+    }
+  }
+}
+
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+/*
+** This function is called as part of inner-loop generation for a SELECT
+** statement with an ORDER BY that is not optimized by an index. It
+** determines the expressions, if any, that the sorter-reference
+** optimization should be used for. The sorter-reference optimization
+** is used for SELECT queries like:
+**
+**   SELECT a, bigblob FROM t1 ORDER BY a LIMIT 10
+**
+** If the optimization is used for expression "bigblob", then instead of
+** storing values read from that column in the sorter records, the PK of
+** the row from table t1 is stored instead. Then, as records are extracted from
+** the sorter to return to the user, the required value of bigblob is
+** retrieved directly from table t1. If the values are very large, this
+** can be more efficient than storing them directly in the sorter records.
+**
+** The ExprList_item.fg.bSorterRef flag is set for each expression in pEList
+** for which the sorter-reference optimization should be enabled.
+** Additionally, the pSort->aDefer[] array is populated with entries
+** for all cursors required to evaluate all selected expressions. Finally.
+** output variable (*ppExtra) is set to an expression list containing
+** expressions for all extra PK values that should be stored in the
+** sorter records.
+*/
+static void selectExprDefer(
+  Parse *pParse,                  /* Leave any error here */
+  SortCtx *pSort,                 /* Sorter context */
+  ExprList *pEList,               /* Expressions destined for sorter */
+  ExprList **ppExtra              /* Expressions to append to sorter record */
+){
+  int i;
+  int nDefer = 0;
+  ExprList *pExtra = 0;
+  for(i=0; i<pEList->nExpr; i++){
+    struct ExprList_item *pItem = &pEList->a[i];
+    if( pItem->u.x.iOrderByCol==0 ){
+      Expr *pExpr = pItem->pExpr;
+      Table *pTab;
+      if( pExpr->op==TK_COLUMN
+       && pExpr->iColumn>=0
+       && ALWAYS( ExprUseYTab(pExpr) )
+       && (pTab = pExpr->y.pTab)!=0
+       && IsOrdinaryTable(pTab)
+       && (pTab->aCol[pExpr->iColumn].colFlags & COLFLAG_SORTERREF)!=0
+      ){
+        int j;
+        for(j=0; j<nDefer; j++){
+          if( pSort->aDefer[j].iCsr==pExpr->iTable ) break;
+        }
+        if( j==nDefer ){
+          if( nDefer==ArraySize(pSort->aDefer) ){
+            continue;
+          }else{
+            int nKey = 1;
+            int k;
+            Index *pPk = 0;
+            if( !HasRowid(pTab) ){
+              pPk = sqlite3PrimaryKeyIndex(pTab);
+              nKey = pPk->nKeyCol;
+            }
+            for(k=0; k<nKey; k++){
+              Expr *pNew = sqlite3PExpr(pParse, TK_COLUMN, 0, 0);
+              if( pNew ){
+                pNew->iTable = pExpr->iTable;
+                assert( ExprUseYTab(pNew) );
+                pNew->y.pTab = pExpr->y.pTab;
+                pNew->iColumn = pPk ? pPk->aiColumn[k] : -1;
+                pExtra = sqlite3ExprListAppend(pParse, pExtra, pNew);
+              }
+            }
+            pSort->aDefer[nDefer].pTab = pExpr->y.pTab;
+            pSort->aDefer[nDefer].iCsr = pExpr->iTable;
+            pSort->aDefer[nDefer].nKey = nKey;
+            nDefer++;
+          }
+        }
+        pItem->fg.bSorterRef = 1;
+      }
+    }
+  }
+  pSort->nDefer = (u8)nDefer;
+  *ppExtra = pExtra;
+}
+#endif
+
+/*
+** This routine generates the code for the inside of the inner loop
+** of a SELECT.
+**
+** If srcTab is negative, then the p->pEList expressions
+** are evaluated in order to get the data for this row.  If srcTab is
+** zero or more, then data is pulled from srcTab and p->pEList is used only
+** to get the number of columns and the collation sequence for each column.
+*/
+static void selectInnerLoop(
+  Parse *pParse,          /* The parser context */
+  Select *p,              /* The complete select statement being coded */
+  int srcTab,             /* Pull data from this table if non-negative */
+  SortCtx *pSort,         /* If not NULL, info on how to process ORDER BY */
+  DistinctCtx *pDistinct, /* If not NULL, info on how to process DISTINCT */
+  SelectDest *pDest,      /* How to dispose of the results */
+  int iContinue,          /* Jump here to continue with next row */
+  int iBreak              /* Jump here to break out of the inner loop */
+){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  int hasDistinct;            /* True if the DISTINCT keyword is present */
+  int eDest = pDest->eDest;   /* How to dispose of results */
+  int iParm = pDest->iSDParm; /* First argument to disposal method */
+  int nResultCol;             /* Number of result columns */
+  int nPrefixReg = 0;         /* Number of extra registers before regResult */
+  RowLoadInfo sRowLoadInfo;   /* Info for deferred row loading */
+
+  /* Usually, regResult is the first cell in an array of memory cells
+  ** containing the current result row. In this case regOrig is set to the
+  ** same value. However, if the results are being sent to the sorter, the
+  ** values for any expressions that are also part of the sort-key are omitted
+  ** from this array. In this case regOrig is set to zero.  */
+  int regResult;              /* Start of memory holding current results */
+  int regOrig;                /* Start of memory holding full result (or 0) */
+
+  assert( v );
+  assert( p->pEList!=0 );
+  hasDistinct = pDistinct ? pDistinct->eTnctType : WHERE_DISTINCT_NOOP;
+  if( pSort && pSort->pOrderBy==0 ) pSort = 0;
+  if( pSort==0 && !hasDistinct ){
+    assert( iContinue!=0 );
+    codeOffset(v, p->iOffset, iContinue);
+  }
+
+  /* Pull the requested columns.
+  */
+  nResultCol = p->pEList->nExpr;
+
+  if( pDest->iSdst==0 ){
+    if( pSort ){
+      nPrefixReg = pSort->pOrderBy->nExpr;
+      if( !(pSort->sortFlags & SORTFLAG_UseSorter) ) nPrefixReg++;
+      pParse->nMem += nPrefixReg;
+    }
+    pDest->iSdst = pParse->nMem+1;
+    pParse->nMem += nResultCol;
+  }else if( pDest->iSdst+nResultCol > pParse->nMem ){
+    /* This is an error condition that can result, for example, when a SELECT
+    ** on the right-hand side of an INSERT contains more result columns than
+    ** there are columns in the table on the left.  The error will be caught
+    ** and reported later.  But we need to make sure enough memory is allocated
+    ** to avoid other spurious errors in the meantime. */
+    pParse->nMem += nResultCol;
+  }
+  pDest->nSdst = nResultCol;
+  regOrig = regResult = pDest->iSdst;
+  if( srcTab>=0 ){
+    for(i=0; i<nResultCol; i++){
+      sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
+      VdbeComment((v, "%s", p->pEList->a[i].zEName));
+    }
+  }else if( eDest!=SRT_Exists ){
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    ExprList *pExtra = 0;
+#endif
+    /* If the destination is an EXISTS(...) expression, the actual
+    ** values returned by the SELECT are not required.
+    */
+    u8 ecelFlags;    /* "ecel" is an abbreviation of "ExprCodeExprList" */
+    ExprList *pEList;
+    if( eDest==SRT_Mem || eDest==SRT_Output || eDest==SRT_Coroutine ){
+      ecelFlags = SQLITE_ECEL_DUP;
+    }else{
+      ecelFlags = 0;
+    }
+    if( pSort && hasDistinct==0 && eDest!=SRT_EphemTab && eDest!=SRT_Table ){
+      /* For each expression in p->pEList that is a copy of an expression in
+      ** the ORDER BY clause (pSort->pOrderBy), set the associated
+      ** iOrderByCol value to one more than the index of the ORDER BY
+      ** expression within the sort-key that pushOntoSorter() will generate.
+      ** This allows the p->pEList field to be omitted from the sorted record,
+      ** saving space and CPU cycles.  */
+      ecelFlags |= (SQLITE_ECEL_OMITREF|SQLITE_ECEL_REF);
+
+      for(i=pSort->nOBSat; i<pSort->pOrderBy->nExpr; i++){
+        int j;
+        if( (j = pSort->pOrderBy->a[i].u.x.iOrderByCol)>0 ){
+          p->pEList->a[j-1].u.x.iOrderByCol = i+1-pSort->nOBSat;
+        }
+      }
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+      selectExprDefer(pParse, pSort, p->pEList, &pExtra);
+      if( pExtra && pParse->db->mallocFailed==0 ){
+        /* If there are any extra PK columns to add to the sorter records,
+        ** allocate extra memory cells and adjust the OpenEphemeral
+        ** instruction to account for the larger records. This is only
+        ** required if there are one or more WITHOUT ROWID tables with
+        ** composite primary keys in the SortCtx.aDefer[] array.  */
+        VdbeOp *pOp = sqlite3VdbeGetOp(v, pSort->addrSortIndex);
+        pOp->p2 += (pExtra->nExpr - pSort->nDefer);
+        pOp->p4.pKeyInfo->nAllField += (pExtra->nExpr - pSort->nDefer);
+        pParse->nMem += pExtra->nExpr;
+      }
+#endif
+
+      /* Adjust nResultCol to account for columns that are omitted
+      ** from the sorter by the optimizations in this branch */
+      pEList = p->pEList;
+      for(i=0; i<pEList->nExpr; i++){
+        if( pEList->a[i].u.x.iOrderByCol>0
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+         || pEList->a[i].fg.bSorterRef
+#endif
+        ){
+          nResultCol--;
+          regOrig = 0;
+        }
+      }
+
+      testcase( regOrig );
+      testcase( eDest==SRT_Set );
+      testcase( eDest==SRT_Mem );
+      testcase( eDest==SRT_Coroutine );
+      testcase( eDest==SRT_Output );
+      assert( eDest==SRT_Set || eDest==SRT_Mem
+           || eDest==SRT_Coroutine || eDest==SRT_Output
+           || eDest==SRT_Upfrom );
+    }
+    sRowLoadInfo.regResult = regResult;
+    sRowLoadInfo.ecelFlags = ecelFlags;
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    sRowLoadInfo.pExtra = pExtra;
+    sRowLoadInfo.regExtraResult = regResult + nResultCol;
+    if( pExtra ) nResultCol += pExtra->nExpr;
+#endif
+    if( p->iLimit
+     && (ecelFlags & SQLITE_ECEL_OMITREF)!=0
+     && nPrefixReg>0
+    ){
+      assert( pSort!=0 );
+      assert( hasDistinct==0 );
+      pSort->pDeferredRowLoad = &sRowLoadInfo;
+      regOrig = 0;
+    }else{
+      innerLoopLoadRow(pParse, p, &sRowLoadInfo);
+    }
+  }
+
+  /* If the DISTINCT keyword was present on the SELECT statement
+  ** and this row has been seen before, then do not make this row
+  ** part of the result.
+  */
+  if( hasDistinct ){
+    int eType = pDistinct->eTnctType;
+    int iTab = pDistinct->tabTnct;
+    assert( nResultCol==p->pEList->nExpr );
+    iTab = codeDistinct(pParse, eType, iTab, iContinue, p->pEList, regResult);
+    fixDistinctOpenEph(pParse, eType, iTab, pDistinct->addrTnct);
+    if( pSort==0 ){
+      codeOffset(v, p->iOffset, iContinue);
+    }
+  }
+
+  switch( eDest ){
+    /* In this mode, write each query result to the key of the temporary
+    ** table iParm.
+    */
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+    case SRT_Union: {
+      int r1;
+      r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, nResultCol);
+      sqlite3ReleaseTempReg(pParse, r1);
+      break;
+    }
+
+    /* Construct a record from the query result, but instead of
+    ** saving that record, use it as a key to delete elements from
+    ** the temporary table iParm.
+    */
+    case SRT_Except: {
+      sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nResultCol);
+      break;
+    }
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+    /* Store the result as data using a unique key.
+    */
+    case SRT_Fifo:
+    case SRT_DistFifo:
+    case SRT_Table:
+    case SRT_EphemTab: {
+      int r1 = sqlite3GetTempRange(pParse, nPrefixReg+1);
+      testcase( eDest==SRT_Table );
+      testcase( eDest==SRT_EphemTab );
+      testcase( eDest==SRT_Fifo );
+      testcase( eDest==SRT_DistFifo );
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1+nPrefixReg);
+#if !defined(SQLITE_ENABLE_NULL_TRIM) && defined(SQLITE_DEBUG)
+      /* A destination of SRT_Table and a non-zero iSDParm2 parameter means
+      ** that this is an "UPDATE ... FROM" on a virtual table or view. In this
+      ** case set the p5 parameter of the OP_MakeRecord to OPFLAG_NOCHNG_MAGIC.
+      ** This does not affect operation in any way - it just allows MakeRecord
+      ** to process OPFLAG_NOCHANGE values without an assert() failing. */
+      if( eDest==SRT_Table && pDest->iSDParm2 ){
+        sqlite3VdbeChangeP5(v, OPFLAG_NOCHNG_MAGIC);
+      }
+#endif
+#ifndef SQLITE_OMIT_CTE
+      if( eDest==SRT_DistFifo ){
+        /* If the destination is DistFifo, then cursor (iParm+1) is open
+        ** on an ephemeral index. If the current row is already present
+        ** in the index, do not write it to the output. If not, add the
+        ** current row to the index and proceed with writing it to the
+        ** output table as well.  */
+        int addr = sqlite3VdbeCurrentAddr(v) + 4;
+        sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, addr, r1, 0);
+        VdbeCoverage(v);
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm+1, r1,regResult,nResultCol);
+        assert( pSort==0 );
+      }
+#endif
+      if( pSort ){
+        assert( regResult==regOrig );
+        pushOntoSorter(pParse, pSort, p, r1+nPrefixReg, regOrig, 1, nPrefixReg);
+      }else{
+        int r2 = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
+        sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
+        sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+        sqlite3ReleaseTempReg(pParse, r2);
+      }
+      sqlite3ReleaseTempRange(pParse, r1, nPrefixReg+1);
+      break;
+    }
+
+    case SRT_Upfrom: {
+      if( pSort ){
+        pushOntoSorter(
+            pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg);
+      }else{
+        int i2 = pDest->iSDParm2;
+        int r1 = sqlite3GetTempReg(pParse);
+
+        /* If the UPDATE FROM join is an aggregate that matches no rows, it
+        ** might still be trying to return one row, because that is what
+        ** aggregates do.  Don't record that empty row in the output table. */
+        sqlite3VdbeAddOp2(v, OP_IsNull, regResult, iBreak); VdbeCoverage(v);
+
+        sqlite3VdbeAddOp3(v, OP_MakeRecord,
+                          regResult+(i2<0), nResultCol-(i2<0), r1);
+        if( i2<0 ){
+          sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, regResult);
+        }else{
+          sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, i2);
+        }
+      }
+      break;
+    }
+
+#ifndef SQLITE_OMIT_SUBQUERY
+    /* If we are creating a set for an "expr IN (SELECT ...)" construct,
+    ** then there should be a single item on the stack.  Write this
+    ** item into the set table with bogus data.
+    */
+    case SRT_Set: {
+      if( pSort ){
+        /* At first glance you would think we could optimize out the
+        ** ORDER BY in this case since the order of entries in the set
+        ** does not matter.  But there might be a LIMIT clause, in which
+        ** case the order does matter */
+        pushOntoSorter(
+            pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg);
+        pDest->iSDParm2 = 0; /* Signal that any Bloom filter is unpopulated */
+      }else{
+        int r1 = sqlite3GetTempReg(pParse);
+        assert( sqlite3Strlen30(pDest->zAffSdst)==nResultCol );
+        sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, nResultCol,
+            r1, pDest->zAffSdst, nResultCol);
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, nResultCol);
+        if( pDest->iSDParm2 ){
+          sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pDest->iSDParm2, 0,
+                               regResult, nResultCol);
+          ExplainQueryPlan((pParse, 0, "CREATE BLOOM FILTER"));
+        }
+        sqlite3ReleaseTempReg(pParse, r1);
+      }
+      break;
+    }
+
+
+    /* If any row exist in the result set, record that fact and abort.
+    */
+    case SRT_Exists: {
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
+      /* The LIMIT clause will terminate the loop for us */
+      break;
+    }
+
+    /* If this is a scalar select that is part of an expression, then
+    ** store the results in the appropriate memory cell or array of
+    ** memory cells and break out of the scan loop.
+    */
+    case SRT_Mem: {
+      if( pSort ){
+        assert( nResultCol<=pDest->nSdst );
+        pushOntoSorter(
+            pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg);
+      }else{
+        assert( nResultCol==pDest->nSdst );
+        assert( regResult==iParm );
+        /* The LIMIT clause will jump out of the loop for us */
+      }
+      break;
+    }
+#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
+
+    case SRT_Coroutine:       /* Send data to a co-routine */
+    case SRT_Output: {        /* Return the results */
+      testcase( eDest==SRT_Coroutine );
+      testcase( eDest==SRT_Output );
+      if( pSort ){
+        pushOntoSorter(pParse, pSort, p, regResult, regOrig, nResultCol,
+                       nPrefixReg);
+      }else if( eDest==SRT_Coroutine ){
+        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nResultCol);
+      }
+      break;
+    }
+
+#ifndef SQLITE_OMIT_CTE
+    /* Write the results into a priority queue that is order according to
+    ** pDest->pOrderBy (in pSO).  pDest->iSDParm (in iParm) is the cursor for an
+    ** index with pSO->nExpr+2 columns.  Build a key using pSO for the first
+    ** pSO->nExpr columns, then make sure all keys are unique by adding a
+    ** final OP_Sequence column.  The last column is the record as a blob.
+    */
+    case SRT_DistQueue:
+    case SRT_Queue: {
+      int nKey;
+      int r1, r2, r3;
+      int addrTest = 0;
+      ExprList *pSO;
+      pSO = pDest->pOrderBy;
+      assert( pSO );
+      nKey = pSO->nExpr;
+      r1 = sqlite3GetTempReg(pParse);
+      r2 = sqlite3GetTempRange(pParse, nKey+2);
+      r3 = r2+nKey+1;
+      if( eDest==SRT_DistQueue ){
+        /* If the destination is DistQueue, then cursor (iParm+1) is open
+        ** on a second ephemeral index that holds all values every previously
+        ** added to the queue. */
+        addrTest = sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, 0,
+                                        regResult, nResultCol);
+        VdbeCoverage(v);
+      }
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r3);
+      if( eDest==SRT_DistQueue ){
+        sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm+1, r3);
+        sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+      }
+      for(i=0; i<nKey; i++){
+        sqlite3VdbeAddOp2(v, OP_SCopy,
+                          regResult + pSO->a[i].u.x.iOrderByCol - 1,
+                          r2+i);
+      }
+      sqlite3VdbeAddOp2(v, OP_Sequence, iParm, r2+nKey);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, r2, nKey+2, r1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, r2, nKey+2);
+      if( addrTest ) sqlite3VdbeJumpHere(v, addrTest);
+      sqlite3ReleaseTempReg(pParse, r1);
+      sqlite3ReleaseTempRange(pParse, r2, nKey+2);
+      break;
+    }
+#endif /* SQLITE_OMIT_CTE */
+
+
+
+#if !defined(SQLITE_OMIT_TRIGGER)
+    /* Discard the results.  This is used for SELECT statements inside
+    ** the body of a TRIGGER.  The purpose of such selects is to call
+    ** user-defined functions that have side effects.  We do not care
+    ** about the actual results of the select.
+    */
+    default: {
+      assert( eDest==SRT_Discard );
+      break;
+    }
+#endif
+  }
+
+  /* Jump to the end of the loop if the LIMIT is reached.  Except, if
+  ** there is a sorter, in which case the sorter has already limited
+  ** the output for us.
+  */
+  if( pSort==0 && p->iLimit ){
+    sqlite3VdbeAddOp2(v, OP_DecrJumpZero, p->iLimit, iBreak); VdbeCoverage(v);
+  }
+}
+
+/*
+** Allocate a KeyInfo object sufficient for an index of N key columns and
+** X extra columns.
+*/
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoAlloc(sqlite3 *db, int N, int X){
+  int nExtra = (N+X)*(sizeof(CollSeq*)+1) - sizeof(CollSeq*);
+  KeyInfo *p = sqlite3DbMallocRawNN(db, sizeof(KeyInfo) + nExtra);
+  if( p ){
+    p->aSortFlags = (u8*)&p->aColl[N+X];
+    p->nKeyField = (u16)N;
+    p->nAllField = (u16)(N+X);
+    p->enc = ENC(db);
+    p->db = db;
+    p->nRef = 1;
+    memset(&p[1], 0, nExtra);
+  }else{
+    return (KeyInfo*)sqlite3OomFault(db);
+  }
+  return p;
+}
+
+/*
+** Deallocate a KeyInfo object
+*/
+SQLITE_PRIVATE void sqlite3KeyInfoUnref(KeyInfo *p){
+  if( p ){
+    assert( p->db!=0 );
+    assert( p->nRef>0 );
+    p->nRef--;
+    if( p->nRef==0 ) sqlite3DbNNFreeNN(p->db, p);
+  }
+}
+
+/*
+** Make a new pointer to a KeyInfo object
+*/
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoRef(KeyInfo *p){
+  if( p ){
+    assert( p->nRef>0 );
+    p->nRef++;
+  }
+  return p;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Return TRUE if a KeyInfo object can be change.  The KeyInfo object
+** can only be changed if this is just a single reference to the object.
+**
+** This routine is used only inside of assert() statements.
+*/
+SQLITE_PRIVATE int sqlite3KeyInfoIsWriteable(KeyInfo *p){ return p->nRef==1; }
+#endif /* SQLITE_DEBUG */
+
+/*
+** Given an expression list, generate a KeyInfo structure that records
+** the collating sequence for each expression in that expression list.
+**
+** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
+** KeyInfo structure is appropriate for initializing a virtual index to
+** implement that clause.  If the ExprList is the result set of a SELECT
+** then the KeyInfo structure is appropriate for initializing a virtual
+** index to implement a DISTINCT test.
+**
+** Space to hold the KeyInfo structure is obtained from malloc.  The calling
+** function is responsible for seeing that this structure is eventually
+** freed.
+*/
+SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoFromExprList(
+  Parse *pParse,       /* Parsing context */
+  ExprList *pList,     /* Form the KeyInfo object from this ExprList */
+  int iStart,          /* Begin with this column of pList */
+  int nExtra           /* Add this many extra columns to the end */
+){
+  int nExpr;
+  KeyInfo *pInfo;
+  struct ExprList_item *pItem;
+  sqlite3 *db = pParse->db;
+  int i;
+
+  nExpr = pList->nExpr;
+  pInfo = sqlite3KeyInfoAlloc(db, nExpr-iStart, nExtra+1);
+  if( pInfo ){
+    assert( sqlite3KeyInfoIsWriteable(pInfo) );
+    for(i=iStart, pItem=pList->a+iStart; i<nExpr; i++, pItem++){
+      pInfo->aColl[i-iStart] = sqlite3ExprNNCollSeq(pParse, pItem->pExpr);
+      pInfo->aSortFlags[i-iStart] = pItem->fg.sortFlags;
+    }
+  }
+  return pInfo;
+}
+
+/*
+** Name of the connection operator, used for error messages.
+*/
+SQLITE_PRIVATE const char *sqlite3SelectOpName(int id){
+  char *z;
+  switch( id ){
+    case TK_ALL:       z = "UNION ALL";   break;
+    case TK_INTERSECT: z = "INTERSECT";   break;
+    case TK_EXCEPT:    z = "EXCEPT";      break;
+    default:           z = "UNION";       break;
+  }
+  return z;
+}
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
+** is a no-op. Otherwise, it adds a single row of output to the EQP result,
+** where the caption is of the form:
+**
+**   "USE TEMP B-TREE FOR xxx"
+**
+** where xxx is one of "DISTINCT", "ORDER BY" or "GROUP BY". Exactly which
+** is determined by the zUsage argument.
+*/
+static void explainTempTable(Parse *pParse, const char *zUsage){
+  ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s", zUsage));
+}
+
+/*
+** Assign expression b to lvalue a. A second, no-op, version of this macro
+** is provided when SQLITE_OMIT_EXPLAIN is defined. This allows the code
+** in sqlite3Select() to assign values to structure member variables that
+** only exist if SQLITE_OMIT_EXPLAIN is not defined without polluting the
+** code with #ifndef directives.
+*/
+# define explainSetInteger(a, b) a = b
+
+#else
+/* No-op versions of the explainXXX() functions and macros. */
+# define explainTempTable(y,z)
+# define explainSetInteger(y,z)
+#endif
+
+
+/*
+** If the inner loop was generated using a non-null pOrderBy argument,
+** then the results were placed in a sorter.  After the loop is terminated
+** we need to run the sorter and output the results.  The following
+** routine generates the code needed to do that.
+*/
+static void generateSortTail(
+  Parse *pParse,    /* Parsing context */
+  Select *p,        /* The SELECT statement */
+  SortCtx *pSort,   /* Information on the ORDER BY clause */
+  int nColumn,      /* Number of columns of data */
+  SelectDest *pDest /* Write the sorted results here */
+){
+  Vdbe *v = pParse->pVdbe;                     /* The prepared statement */
+  int addrBreak = pSort->labelDone;            /* Jump here to exit loop */
+  int addrContinue = sqlite3VdbeMakeLabel(pParse);/* Jump here for next cycle */
+  int addr;                       /* Top of output loop. Jump for Next. */
+  int addrOnce = 0;
+  int iTab;
+  ExprList *pOrderBy = pSort->pOrderBy;
+  int eDest = pDest->eDest;
+  int iParm = pDest->iSDParm;
+  int regRow;
+  int regRowid;
+  int iCol;
+  int nKey;                       /* Number of key columns in sorter record */
+  int iSortTab;                   /* Sorter cursor to read from */
+  int i;
+  int bSeq;                       /* True if sorter record includes seq. no. */
+  int nRefKey = 0;
+  struct ExprList_item *aOutEx = p->pEList->a;
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrExplain;                /* Address of OP_Explain instruction */
+#endif
+
+  nKey = pOrderBy->nExpr - pSort->nOBSat;
+  if( pSort->nOBSat==0 || nKey==1 ){
+    ExplainQueryPlan2(addrExplain, (pParse, 0,
+      "USE TEMP B-TREE FOR %sORDER BY", pSort->nOBSat?"LAST TERM OF ":""
+    ));
+  }else{
+    ExplainQueryPlan2(addrExplain, (pParse, 0,
+      "USE TEMP B-TREE FOR LAST %d TERMS OF ORDER BY", nKey
+    ));
+  }
+  sqlite3VdbeScanStatusRange(v, addrExplain,pSort->addrPush,pSort->addrPushEnd);
+  sqlite3VdbeScanStatusCounters(v, addrExplain, addrExplain, pSort->addrPush);
+
+
+  assert( addrBreak<0 );
+  if( pSort->labelBkOut ){
+    sqlite3VdbeAddOp2(v, OP_Gosub, pSort->regReturn, pSort->labelBkOut);
+    sqlite3VdbeGoto(v, addrBreak);
+    sqlite3VdbeResolveLabel(v, pSort->labelBkOut);
+  }
+
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  /* Open any cursors needed for sorter-reference expressions */
+  for(i=0; i<pSort->nDefer; i++){
+    Table *pTab = pSort->aDefer[i].pTab;
+    int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+    sqlite3OpenTable(pParse, pSort->aDefer[i].iCsr, iDb, pTab, OP_OpenRead);
+    nRefKey = MAX(nRefKey, pSort->aDefer[i].nKey);
+  }
+#endif
+
+  iTab = pSort->iECursor;
+  if( eDest==SRT_Output || eDest==SRT_Coroutine || eDest==SRT_Mem ){
+    if( eDest==SRT_Mem && p->iOffset ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, pDest->iSdst);
+    }
+    regRowid = 0;
+    regRow = pDest->iSdst;
+  }else{
+    regRowid = sqlite3GetTempReg(pParse);
+    if( eDest==SRT_EphemTab || eDest==SRT_Table ){
+      regRow = sqlite3GetTempReg(pParse);
+      nColumn = 0;
+    }else{
+      regRow = sqlite3GetTempRange(pParse, nColumn);
+    }
+  }
+  if( pSort->sortFlags & SORTFLAG_UseSorter ){
+    int regSortOut = ++pParse->nMem;
+    iSortTab = pParse->nTab++;
+    if( pSort->labelBkOut ){
+      addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+    }
+    sqlite3VdbeAddOp3(v, OP_OpenPseudo, iSortTab, regSortOut,
+        nKey+1+nColumn+nRefKey);
+    if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
+    addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak);
+    VdbeCoverage(v);
+    assert( p->iLimit==0 && p->iOffset==0 );
+    sqlite3VdbeAddOp3(v, OP_SorterData, iTab, regSortOut, iSortTab);
+    bSeq = 0;
+  }else{
+    addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak); VdbeCoverage(v);
+    codeOffset(v, p->iOffset, addrContinue);
+    iSortTab = iTab;
+    bSeq = 1;
+    if( p->iOffset>0 ){
+      sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
+    }
+  }
+  for(i=0, iCol=nKey+bSeq-1; i<nColumn; i++){
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( aOutEx[i].fg.bSorterRef ) continue;
+#endif
+    if( aOutEx[i].u.x.iOrderByCol==0 ) iCol++;
+  }
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+  if( pSort->nDefer ){
+    int iKey = iCol+1;
+    int regKey = sqlite3GetTempRange(pParse, nRefKey);
+
+    for(i=0; i<pSort->nDefer; i++){
+      int iCsr = pSort->aDefer[i].iCsr;
+      Table *pTab = pSort->aDefer[i].pTab;
+      int nKey = pSort->aDefer[i].nKey;
+
+      sqlite3VdbeAddOp1(v, OP_NullRow, iCsr);
+      if( HasRowid(pTab) ){
+        sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iKey++, regKey);
+        sqlite3VdbeAddOp3(v, OP_SeekRowid, iCsr,
+            sqlite3VdbeCurrentAddr(v)+1, regKey);
+      }else{
+        int k;
+        int iJmp;
+        assert( sqlite3PrimaryKeyIndex(pTab)->nKeyCol==nKey );
+        for(k=0; k<nKey; k++){
+          sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iKey++, regKey+k);
+        }
+        iJmp = sqlite3VdbeCurrentAddr(v);
+        sqlite3VdbeAddOp4Int(v, OP_SeekGE, iCsr, iJmp+2, regKey, nKey);
+        sqlite3VdbeAddOp4Int(v, OP_IdxLE, iCsr, iJmp+3, regKey, nKey);
+        sqlite3VdbeAddOp1(v, OP_NullRow, iCsr);
+      }
+    }
+    sqlite3ReleaseTempRange(pParse, regKey, nRefKey);
+  }
+#endif
+  for(i=nColumn-1; i>=0; i--){
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    if( aOutEx[i].fg.bSorterRef ){
+      sqlite3ExprCode(pParse, aOutEx[i].pExpr, regRow+i);
+    }else
+#endif
+    {
+      int iRead;
+      if( aOutEx[i].u.x.iOrderByCol ){
+        iRead = aOutEx[i].u.x.iOrderByCol-1;
+      }else{
+        iRead = iCol--;
+      }
+      sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iRead, regRow+i);
+      VdbeComment((v, "%s", aOutEx[i].zEName));
+    }
+  }
+  sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1);
+  switch( eDest ){
+    case SRT_Table:
+    case SRT_EphemTab: {
+      sqlite3VdbeAddOp3(v, OP_Column, iSortTab, nKey+bSeq, regRow);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, iParm, regRow, regRowid);
+      sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case SRT_Set: {
+      assert( nColumn==sqlite3Strlen30(pDest->zAffSdst) );
+      sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, nColumn, regRowid,
+                        pDest->zAffSdst, nColumn);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, regRowid, regRow, nColumn);
+      break;
+    }
+    case SRT_Mem: {
+      /* The LIMIT clause will terminate the loop for us */
+      break;
+    }
+#endif
+    case SRT_Upfrom: {
+      int i2 = pDest->iSDParm2;
+      int r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord,regRow+(i2<0),nColumn-(i2<0),r1);
+      if( i2<0 ){
+        sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, regRow);
+      }else{
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regRow, i2);
+      }
+      break;
+    }
+    default: {
+      assert( eDest==SRT_Output || eDest==SRT_Coroutine );
+      testcase( eDest==SRT_Output );
+      testcase( eDest==SRT_Coroutine );
+      if( eDest==SRT_Output ){
+        sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iSdst, nColumn);
+      }else{
+        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
+      }
+      break;
+    }
+  }
+  if( regRowid ){
+    if( eDest==SRT_Set ){
+      sqlite3ReleaseTempRange(pParse, regRow, nColumn);
+    }else{
+      sqlite3ReleaseTempReg(pParse, regRow);
+    }
+    sqlite3ReleaseTempReg(pParse, regRowid);
+  }
+  /* The bottom of the loop
+  */
+  sqlite3VdbeResolveLabel(v, addrContinue);
+  if( pSort->sortFlags & SORTFLAG_UseSorter ){
+    sqlite3VdbeAddOp2(v, OP_SorterNext, iTab, addr); VdbeCoverage(v);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Next, iTab, addr); VdbeCoverage(v);
+  }
+  sqlite3VdbeScanStatusRange(v, addrExplain, sqlite3VdbeCurrentAddr(v)-1, -1);
+  if( pSort->regReturn ) sqlite3VdbeAddOp1(v, OP_Return, pSort->regReturn);
+  sqlite3VdbeResolveLabel(v, addrBreak);
+}
+
+/*
+** Return a pointer to a string containing the 'declaration type' of the
+** expression pExpr. The string may be treated as static by the caller.
+**
+** The declaration type is the exact datatype definition extracted from the
+** original CREATE TABLE statement if the expression is a column. The
+** declaration type for a ROWID field is INTEGER. Exactly when an expression
+** is considered a column can be complex in the presence of subqueries. The
+** result-set expression in all of the following SELECT statements is
+** considered a column by this function.
+**
+**   SELECT col FROM tbl;
+**   SELECT (SELECT col FROM tbl;
+**   SELECT (SELECT col FROM tbl);
+**   SELECT abc FROM (SELECT col AS abc FROM tbl);
+**
+** The declaration type for any expression other than a column is NULL.
+**
+** This routine has either 3 or 6 parameters depending on whether or not
+** the SQLITE_ENABLE_COLUMN_METADATA compile-time option is used.
+*/
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+# define columnType(A,B,C,D,E) columnTypeImpl(A,B,C,D,E)
+#else /* if !defined(SQLITE_ENABLE_COLUMN_METADATA) */
+# define columnType(A,B,C,D,E) columnTypeImpl(A,B)
+#endif
+static const char *columnTypeImpl(
+  NameContext *pNC,
+#ifndef SQLITE_ENABLE_COLUMN_METADATA
+  Expr *pExpr
+#else
+  Expr *pExpr,
+  const char **pzOrigDb,
+  const char **pzOrigTab,
+  const char **pzOrigCol
+#endif
+){
+  char const *zType = 0;
+  int j;
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+  char const *zOrigDb = 0;
+  char const *zOrigTab = 0;
+  char const *zOrigCol = 0;
+#endif
+
+  assert( pExpr!=0 );
+  assert( pNC->pSrcList!=0 );
+  switch( pExpr->op ){
+    case TK_COLUMN: {
+      /* The expression is a column. Locate the table the column is being
+      ** extracted from in NameContext.pSrcList. This table may be real
+      ** database table or a subquery.
+      */
+      Table *pTab = 0;            /* Table structure column is extracted from */
+      Select *pS = 0;             /* Select the column is extracted from */
+      int iCol = pExpr->iColumn;  /* Index of column in pTab */
+      while( pNC && !pTab ){
+        SrcList *pTabList = pNC->pSrcList;
+        for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
+        if( j<pTabList->nSrc ){
+          pTab = pTabList->a[j].pSTab;
+          if( pTabList->a[j].fg.isSubquery ){
+            pS = pTabList->a[j].u4.pSubq->pSelect;
+          }else{
+            pS = 0;
+          }
+        }else{
+          pNC = pNC->pNext;
+        }
+      }
+
+      if( pTab==0 ){
+        /* At one time, code such as "SELECT new.x" within a trigger would
+        ** cause this condition to run.  Since then, we have restructured how
+        ** trigger code is generated and so this condition is no longer
+        ** possible. However, it can still be true for statements like
+        ** the following:
+        **
+        **   CREATE TABLE t1(col INTEGER);
+        **   SELECT (SELECT t1.col) FROM FROM t1;
+        **
+        ** when columnType() is called on the expression "t1.col" in the
+        ** sub-select. In this case, set the column type to NULL, even
+        ** though it should really be "INTEGER".
+        **
+        ** This is not a problem, as the column type of "t1.col" is never
+        ** used. When columnType() is called on the expression
+        ** "(SELECT t1.col)", the correct type is returned (see the TK_SELECT
+        ** branch below.  */
+        break;
+      }
+
+      assert( pTab && ExprUseYTab(pExpr) && pExpr->y.pTab==pTab );
+      if( pS ){
+        /* The "table" is actually a sub-select or a view in the FROM clause
+        ** of the SELECT statement. Return the declaration type and origin
+        ** data for the result-set column of the sub-select.
+        */
+        if( iCol<pS->pEList->nExpr
+         && (!ViewCanHaveRowid || iCol>=0)
+        ){
+          /* If iCol is less than zero, then the expression requests the
+          ** rowid of the sub-select or view. This expression is legal (see
+          ** test case misc2.2.2) - it always evaluates to NULL.
+          */
+          NameContext sNC;
+          Expr *p = pS->pEList->a[iCol].pExpr;
+          sNC.pSrcList = pS->pSrc;
+          sNC.pNext = pNC;
+          sNC.pParse = pNC->pParse;
+          zType = columnType(&sNC, p,&zOrigDb,&zOrigTab,&zOrigCol);
+        }
+      }else{
+        /* A real table or a CTE table */
+        assert( !pS );
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+        if( iCol<0 ) iCol = pTab->iPKey;
+        assert( iCol==XN_ROWID || (iCol>=0 && iCol<pTab->nCol) );
+        if( iCol<0 ){
+          zType = "INTEGER";
+          zOrigCol = "rowid";
+        }else{
+          zOrigCol = pTab->aCol[iCol].zCnName;
+          zType = sqlite3ColumnType(&pTab->aCol[iCol],0);
+        }
+        zOrigTab = pTab->zName;
+        if( pNC->pParse && pTab->pSchema ){
+          int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
+          zOrigDb = pNC->pParse->db->aDb[iDb].zDbSName;
+        }
+#else
+        assert( iCol==XN_ROWID || (iCol>=0 && iCol<pTab->nCol) );
+        if( iCol<0 ){
+          zType = "INTEGER";
+        }else{
+          zType = sqlite3ColumnType(&pTab->aCol[iCol],0);
+        }
+#endif
+      }
+      break;
+    }
+#ifndef SQLITE_OMIT_SUBQUERY
+    case TK_SELECT: {
+      /* The expression is a sub-select. Return the declaration type and
+      ** origin info for the single column in the result set of the SELECT
+      ** statement.
+      */
+      NameContext sNC;
+      Select *pS;
+      Expr *p;
+      assert( ExprUseXSelect(pExpr) );
+      pS = pExpr->x.pSelect;
+      p = pS->pEList->a[0].pExpr;
+      sNC.pSrcList = pS->pSrc;
+      sNC.pNext = pNC;
+      sNC.pParse = pNC->pParse;
+      zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
+      break;
+    }
+#endif
+  }
+
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+  if( pzOrigDb ){
+    assert( pzOrigTab && pzOrigCol );
+    *pzOrigDb = zOrigDb;
+    *pzOrigTab = zOrigTab;
+    *pzOrigCol = zOrigCol;
+  }
+#endif
+  return zType;
+}
+
+/*
+** Generate code that will tell the VDBE the declaration types of columns
+** in the result set.
+*/
+static void generateColumnTypes(
+  Parse *pParse,      /* Parser context */
+  SrcList *pTabList,  /* List of tables */
+  ExprList *pEList    /* Expressions defining the result set */
+){
+#ifndef SQLITE_OMIT_DECLTYPE
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  NameContext sNC;
+  sNC.pSrcList = pTabList;
+  sNC.pParse = pParse;
+  sNC.pNext = 0;
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *p = pEList->a[i].pExpr;
+    const char *zType;
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+    const char *zOrigDb = 0;
+    const char *zOrigTab = 0;
+    const char *zOrigCol = 0;
+    zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
+
+    /* The vdbe must make its own copy of the column-type and other
+    ** column specific strings, in case the schema is reset before this
+    ** virtual machine is deleted.
+    */
+    sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, SQLITE_TRANSIENT);
+    sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, SQLITE_TRANSIENT);
+    sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, SQLITE_TRANSIENT);
+#else
+    zType = columnType(&sNC, p, 0, 0, 0);
+#endif
+    sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, SQLITE_TRANSIENT);
+  }
+#endif /* !defined(SQLITE_OMIT_DECLTYPE) */
+}
+
+
+/*
+** Compute the column names for a SELECT statement.
+**
+** The only guarantee that SQLite makes about column names is that if the
+** column has an AS clause assigning it a name, that will be the name used.
+** That is the only documented guarantee.  However, countless applications
+** developed over the years have made baseless assumptions about column names
+** and will break if those assumptions changes.  Hence, use extreme caution
+** when modifying this routine to avoid breaking legacy.
+**
+** See Also: sqlite3ColumnsFromExprList()
+**
+** The PRAGMA short_column_names and PRAGMA full_column_names settings are
+** deprecated.  The default setting is short=ON, full=OFF.  99.9% of all
+** applications should operate this way.  Nevertheless, we need to support the
+** other modes for legacy:
+**
+**    short=OFF, full=OFF:      Column name is the text of the expression has it
+**                              originally appears in the SELECT statement.  In
+**                              other words, the zSpan of the result expression.
+**
+**    short=ON, full=OFF:       (This is the default setting).  If the result
+**                              refers directly to a table column, then the
+**                              result column name is just the table column
+**                              name: COLUMN.  Otherwise use zSpan.
+**
+**    full=ON, short=ANY:       If the result refers directly to a table column,
+**                              then the result column name with the table name
+**                              prefix, ex: TABLE.COLUMN.  Otherwise use zSpan.
+*/
+SQLITE_PRIVATE void sqlite3GenerateColumnNames(
+  Parse *pParse,      /* Parser context */
+  Select *pSelect     /* Generate column names for this SELECT statement */
+){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  Table *pTab;
+  SrcList *pTabList;
+  ExprList *pEList;
+  sqlite3 *db = pParse->db;
+  int fullName;    /* TABLE.COLUMN if no AS clause and is a direct table ref */
+  int srcName;     /* COLUMN or TABLE.COLUMN if no AS clause and is direct */
+
+  if( pParse->colNamesSet ) return;
+  /* Column names are determined by the left-most term of a compound select */
+  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
+  TREETRACE(0x80,pParse,pSelect,("generating column names\n"));
+  pTabList = pSelect->pSrc;
+  pEList = pSelect->pEList;
+  assert( v!=0 );
+  assert( pTabList!=0 );
+  pParse->colNamesSet = 1;
+  fullName = (db->flags & SQLITE_FullColNames)!=0;
+  srcName = (db->flags & SQLITE_ShortColNames)!=0 || fullName;
+  sqlite3VdbeSetNumCols(v, pEList->nExpr);
+  for(i=0; i<pEList->nExpr; i++){
+    Expr *p = pEList->a[i].pExpr;
+
+    assert( p!=0 );
+    assert( p->op!=TK_AGG_COLUMN );  /* Agg processing has not run yet */
+    assert( p->op!=TK_COLUMN
+        || (ExprUseYTab(p) && p->y.pTab!=0) ); /* Covering idx not yet coded */
+    if( pEList->a[i].zEName && pEList->a[i].fg.eEName==ENAME_NAME ){
+      /* An AS clause always takes first priority */
+      char *zName = pEList->a[i].zEName;
+      sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT);
+    }else if( srcName && p->op==TK_COLUMN ){
+      char *zCol;
+      int iCol = p->iColumn;
+      pTab = p->y.pTab;
+      assert( pTab!=0 );
+      if( iCol<0 ) iCol = pTab->iPKey;
+      assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
+      if( iCol<0 ){
+        zCol = "rowid";
+      }else{
+        zCol = pTab->aCol[iCol].zCnName;
+      }
+      if( fullName ){
+        char *zName = 0;
+        zName = sqlite3MPrintf(db, "%s.%s", pTab->zName, zCol);
+        sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_DYNAMIC);
+      }else{
+        sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, SQLITE_TRANSIENT);
+      }
+    }else{
+      const char *z = pEList->a[i].zEName;
+      z = z==0 ? sqlite3MPrintf(db, "column%d", i+1) : sqlite3DbStrDup(db, z);
+      sqlite3VdbeSetColName(v, i, COLNAME_NAME, z, SQLITE_DYNAMIC);
+    }
+  }
+  generateColumnTypes(pParse, pTabList, pEList);
+}
+
+/*
+** Given an expression list (which is really the list of expressions
+** that form the result set of a SELECT statement) compute appropriate
+** column names for a table that would hold the expression list.
+**
+** All column names will be unique.
+**
+** Only the column names are computed.  Column.zType, Column.zColl,
+** and other fields of Column are zeroed.
+**
+** Return SQLITE_OK on success.  If a memory allocation error occurs,
+** store NULL in *paCol and 0 in *pnCol and return SQLITE_NOMEM.
+**
+** The only guarantee that SQLite makes about column names is that if the
+** column has an AS clause assigning it a name, that will be the name used.
+** That is the only documented guarantee.  However, countless applications
+** developed over the years have made baseless assumptions about column names
+** and will break if those assumptions changes.  Hence, use extreme caution
+** when modifying this routine to avoid breaking legacy.
+**
+** See Also: sqlite3GenerateColumnNames()
+*/
+SQLITE_PRIVATE int sqlite3ColumnsFromExprList(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pEList,       /* Expr list from which to derive column names */
+  i16 *pnCol,             /* Write the number of columns here */
+  Column **paCol          /* Write the new column list here */
+){
+  sqlite3 *db = pParse->db;   /* Database connection */
+  int i, j;                   /* Loop counters */
+  u32 cnt;                    /* Index added to make the name unique */
+  Column *aCol, *pCol;        /* For looping over result columns */
+  int nCol;                   /* Number of columns in the result set */
+  char *zName;                /* Column name */
+  int nName;                  /* Size of name in zName[] */
+  Hash ht;                    /* Hash table of column names */
+  Table *pTab;
+
+  sqlite3HashInit(&ht);
+  if( pEList ){
+    nCol = pEList->nExpr;
+    aCol = sqlite3DbMallocZero(db, sizeof(aCol[0])*nCol);
+    testcase( aCol==0 );
+    if( NEVER(nCol>32767) ) nCol = 32767;
+  }else{
+    nCol = 0;
+    aCol = 0;
+  }
+  assert( nCol==(i16)nCol );
+  *pnCol = nCol;
+  *paCol = aCol;
+
+  for(i=0, pCol=aCol; i<nCol && !pParse->nErr; i++, pCol++){
+    struct ExprList_item *pX = &pEList->a[i];
+    struct ExprList_item *pCollide;
+    /* Get an appropriate name for the column
+    */
+    if( (zName = pX->zEName)!=0 && pX->fg.eEName==ENAME_NAME ){
+      /* If the column contains an "AS <name>" phrase, use <name> as the name */
+    }else{
+      Expr *pColExpr = sqlite3ExprSkipCollateAndLikely(pX->pExpr);
+      while( ALWAYS(pColExpr!=0) && pColExpr->op==TK_DOT ){
+        pColExpr = pColExpr->pRight;
+        assert( pColExpr!=0 );
+      }
+      if( pColExpr->op==TK_COLUMN
+       && ALWAYS( ExprUseYTab(pColExpr) )
+       && ALWAYS( pColExpr->y.pTab!=0 )
+      ){
+        /* For columns use the column name name */
+        int iCol = pColExpr->iColumn;
+        pTab = pColExpr->y.pTab;
+        if( iCol<0 ) iCol = pTab->iPKey;
+        zName = iCol>=0 ? pTab->aCol[iCol].zCnName : "rowid";
+      }else if( pColExpr->op==TK_ID ){
+        assert( !ExprHasProperty(pColExpr, EP_IntValue) );
+        zName = pColExpr->u.zToken;
+      }else{
+        /* Use the original text of the column expression as its name */
+        assert( zName==pX->zEName );  /* pointer comparison intended */
+      }
+    }
+    if( zName && !sqlite3IsTrueOrFalse(zName) ){
+      zName = sqlite3DbStrDup(db, zName);
+    }else{
+      zName = sqlite3MPrintf(db,"column%d",i+1);
+    }
+
+    /* Make sure the column name is unique.  If the name is not unique,
+    ** append an integer to the name so that it becomes unique.
+    */
+    cnt = 0;
+    while( zName && (pCollide = sqlite3HashFind(&ht, zName))!=0 ){
+      if( pCollide->fg.bUsingTerm ){
+        pCol->colFlags |= COLFLAG_NOEXPAND;
+      }
+      nName = sqlite3Strlen30(zName);
+      if( nName>0 ){
+        for(j=nName-1; j>0 && sqlite3Isdigit(zName[j]); j--){}
+        if( zName[j]==':' ) nName = j;
+      }
+      zName = sqlite3MPrintf(db, "%.*z:%u", nName, zName, ++cnt);
+      sqlite3ProgressCheck(pParse);
+      if( cnt>3 ){
+        sqlite3_randomness(sizeof(cnt), &cnt);
+      }
+    }
+    pCol->zCnName = zName;
+    pCol->hName = sqlite3StrIHash(zName);
+    if( pX->fg.bNoExpand ){
+      pCol->colFlags |= COLFLAG_NOEXPAND;
+    }
+    sqlite3ColumnPropertiesFromName(0, pCol);
+    if( zName && sqlite3HashInsert(&ht, zName, pX)==pX ){
+      sqlite3OomFault(db);
+    }
+  }
+  sqlite3HashClear(&ht);
+  if( pParse->nErr ){
+    for(j=0; j<i; j++){
+      sqlite3DbFree(db, aCol[j].zCnName);
+    }
+    sqlite3DbFree(db, aCol);
+    *paCol = 0;
+    *pnCol = 0;
+    return pParse->rc;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** pTab is a transient Table object that represents a subquery of some
+** kind (maybe a parenthesized subquery in the FROM clause of a larger
+** query, or a VIEW, or a CTE).  This routine computes type information
+** for that Table object based on the Select object that implements the
+** subquery.  For the purposes of this routine, "type information" means:
+**
+**    *   The datatype name, as it might appear in a CREATE TABLE statement
+**    *   Which collating sequence to use for the column
+**    *   The affinity of the column
+*/
+SQLITE_PRIVATE void sqlite3SubqueryColumnTypes(
+  Parse *pParse,      /* Parsing contexts */
+  Table *pTab,        /* Add column type information to this table */
+  Select *pSelect,    /* SELECT used to determine types and collations */
+  char aff            /* Default affinity. */
+){
+  sqlite3 *db = pParse->db;
+  Column *pCol;
+  CollSeq *pColl;
+  int i,j;
+  Expr *p;
+  struct ExprList_item *a;
+  NameContext sNC;
+
+  assert( pSelect!=0 );
+  assert( (pSelect->selFlags & SF_Resolved)!=0 );
+  assert( pTab->nCol==pSelect->pEList->nExpr || pParse->nErr>0 );
+  assert( aff==SQLITE_AFF_NONE || aff==SQLITE_AFF_BLOB );
+  if( db->mallocFailed || IN_RENAME_OBJECT ) return;
+  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
+  a = pSelect->pEList->a;
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pSrcList = pSelect->pSrc;
+  for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
+    const char *zType;
+    i64 n;
+    int m = 0;
+    Select *pS2 = pSelect;
+    pTab->tabFlags |= (pCol->colFlags & COLFLAG_NOINSERT);
+    p = a[i].pExpr;
+    /* pCol->szEst = ... // Column size est for SELECT tables never used */
+    pCol->affinity = sqlite3ExprAffinity(p);
+    while( pCol->affinity<=SQLITE_AFF_NONE && pS2->pNext!=0 ){
+      m |= sqlite3ExprDataType(pS2->pEList->a[i].pExpr);
+      pS2 = pS2->pNext;
+      pCol->affinity = sqlite3ExprAffinity(pS2->pEList->a[i].pExpr);
+    }
+    if( pCol->affinity<=SQLITE_AFF_NONE ){
+      pCol->affinity = aff;
+    }
+    if( pCol->affinity>=SQLITE_AFF_TEXT && (pS2->pNext || pS2!=pSelect) ){
+      for(pS2=pS2->pNext; pS2; pS2=pS2->pNext){
+        m |= sqlite3ExprDataType(pS2->pEList->a[i].pExpr);
+      }
+      if( pCol->affinity==SQLITE_AFF_TEXT && (m&0x01)!=0 ){
+        pCol->affinity = SQLITE_AFF_BLOB;
+      }else
+      if( pCol->affinity>=SQLITE_AFF_NUMERIC && (m&0x02)!=0 ){
+        pCol->affinity = SQLITE_AFF_BLOB;
+      }
+      if( pCol->affinity>=SQLITE_AFF_NUMERIC && p->op==TK_CAST ){
+        pCol->affinity = SQLITE_AFF_FLEXNUM;
+      }
+    }
+    zType = columnType(&sNC, p, 0, 0, 0);
+    if( zType==0 || pCol->affinity!=sqlite3AffinityType(zType, 0) ){
+      if( pCol->affinity==SQLITE_AFF_NUMERIC
+       || pCol->affinity==SQLITE_AFF_FLEXNUM
+      ){
+        zType = "NUM";
+      }else{
+        zType = 0;
+        for(j=1; j<SQLITE_N_STDTYPE; j++){
+          if( sqlite3StdTypeAffinity[j]==pCol->affinity ){
+            zType = sqlite3StdType[j];
+            break;
+          }
+        }
+      }
+    }
+    if( zType ){
+      const i64 k = sqlite3Strlen30(zType);
+      n = sqlite3Strlen30(pCol->zCnName);
+      pCol->zCnName = sqlite3DbReallocOrFree(db, pCol->zCnName, n+k+2);
+      pCol->colFlags &= ~(COLFLAG_HASTYPE|COLFLAG_HASCOLL);
+      if( pCol->zCnName ){
+        memcpy(&pCol->zCnName[n+1], zType, k+1);
+        pCol->colFlags |= COLFLAG_HASTYPE;
+      }
+    }
+    pColl = sqlite3ExprCollSeq(pParse, p);
+    if( pColl ){
+      assert( pTab->pIndex==0 );
+      sqlite3ColumnSetColl(db, pCol, pColl->zName);
+    }
+  }
+  pTab->szTabRow = 1; /* Any non-zero value works */
+}
+
+/*
+** Given a SELECT statement, generate a Table structure that describes
+** the result set of that SELECT.
+*/
+SQLITE_PRIVATE Table *sqlite3ResultSetOfSelect(Parse *pParse, Select *pSelect, char aff){
+  Table *pTab;
+  sqlite3 *db = pParse->db;
+  u64 savedFlags;
+
+  savedFlags = db->flags;
+  db->flags &= ~(u64)SQLITE_FullColNames;
+  db->flags |= SQLITE_ShortColNames;
+  sqlite3SelectPrep(pParse, pSelect, 0);
+  db->flags = savedFlags;
+  if( pParse->nErr ) return 0;
+  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
+  pTab = sqlite3DbMallocZero(db, sizeof(Table) );
+  if( pTab==0 ){
+    return 0;
+  }
+  pTab->nTabRef = 1;
+  pTab->zName = 0;
+  pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
+  sqlite3ColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
+  sqlite3SubqueryColumnTypes(pParse, pTab, pSelect, aff);
+  pTab->iPKey = -1;
+  if( db->mallocFailed ){
+    sqlite3DeleteTable(db, pTab);
+    return 0;
+  }
+  return pTab;
+}
+
+/*
+** Get a VDBE for the given parser context.  Create a new one if necessary.
+** If an error occurs, return NULL and leave a message in pParse.
+*/
+SQLITE_PRIVATE Vdbe *sqlite3GetVdbe(Parse *pParse){
+  if( pParse->pVdbe ){
+    return pParse->pVdbe;
+  }
+  if( pParse->pToplevel==0
+   && OptimizationEnabled(pParse->db,SQLITE_FactorOutConst)
+  ){
+    pParse->okConstFactor = 1;
+  }
+  return sqlite3VdbeCreate(pParse);
+}
+
+
+/*
+** Compute the iLimit and iOffset fields of the SELECT based on the
+** pLimit expressions.  pLimit->pLeft and pLimit->pRight hold the expressions
+** that appear in the original SQL statement after the LIMIT and OFFSET
+** keywords.  Or NULL if those keywords are omitted. iLimit and iOffset
+** are the integer memory register numbers for counters used to compute
+** the limit and offset.  If there is no limit and/or offset, then
+** iLimit and iOffset are negative.
+**
+** This routine changes the values of iLimit and iOffset only if
+** a limit or offset is defined by pLimit->pLeft and pLimit->pRight.  iLimit
+** and iOffset should have been preset to appropriate default values (zero)
+** prior to calling this routine.
+**
+** The iOffset register (if it exists) is initialized to the value
+** of the OFFSET.  The iLimit register is initialized to LIMIT.  Register
+** iOffset+1 is initialized to LIMIT+OFFSET.
+**
+** Only if pLimit->pLeft!=0 do the limit registers get
+** redefined.  The UNION ALL operator uses this property to force
+** the reuse of the same limit and offset registers across multiple
+** SELECT statements.
+*/
+static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
+  Vdbe *v = 0;
+  int iLimit = 0;
+  int iOffset;
+  int n;
+  Expr *pLimit = p->pLimit;
+
+  if( p->iLimit ) return;
+
+  /*
+  ** "LIMIT -1" always shows all rows.  There is some
+  ** controversy about what the correct behavior should be.
+  ** The current implementation interprets "LIMIT 0" to mean
+  ** no rows.
+  */
+  if( pLimit ){
+    assert( pLimit->op==TK_LIMIT );
+    assert( pLimit->pLeft!=0 );
+    p->iLimit = iLimit = ++pParse->nMem;
+    v = sqlite3GetVdbe(pParse);
+    assert( v!=0 );
+    if( sqlite3ExprIsInteger(pLimit->pLeft, &n, pParse) ){
+      sqlite3VdbeAddOp2(v, OP_Integer, n, iLimit);
+      VdbeComment((v, "LIMIT counter"));
+      if( n==0 ){
+        sqlite3VdbeGoto(v, iBreak);
+      }else if( n>=0 && p->nSelectRow>sqlite3LogEst((u64)n) ){
+        p->nSelectRow = sqlite3LogEst((u64)n);
+        p->selFlags |= SF_FixedLimit;
+      }
+    }else{
+      sqlite3ExprCode(pParse, pLimit->pLeft, iLimit);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit); VdbeCoverage(v);
+      VdbeComment((v, "LIMIT counter"));
+      sqlite3VdbeAddOp2(v, OP_IfNot, iLimit, iBreak); VdbeCoverage(v);
+    }
+    if( pLimit->pRight ){
+      p->iOffset = iOffset = ++pParse->nMem;
+      pParse->nMem++;   /* Allocate an extra register for limit+offset */
+      sqlite3ExprCode(pParse, pLimit->pRight, iOffset);
+      sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset); VdbeCoverage(v);
+      VdbeComment((v, "OFFSET counter"));
+      sqlite3VdbeAddOp3(v, OP_OffsetLimit, iLimit, iOffset+1, iOffset);
+      VdbeComment((v, "LIMIT+OFFSET"));
+    }
+  }
+}
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+/*
+** Return the appropriate collating sequence for the iCol-th column of
+** the result set for the compound-select statement "p".  Return NULL if
+** the column has no default collating sequence.
+**
+** The collating sequence for the compound select is taken from the
+** left-most term of the select that has a collating sequence.
+*/
+static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
+  CollSeq *pRet;
+  if( p->pPrior ){
+    pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
+  }else{
+    pRet = 0;
+  }
+  assert( iCol>=0 );
+  /* iCol must be less than p->pEList->nExpr.  Otherwise an error would
+  ** have been thrown during name resolution and we would not have gotten
+  ** this far */
+  if( pRet==0 && ALWAYS(iCol<p->pEList->nExpr) ){
+    pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
+  }
+  return pRet;
+}
+
+/*
+** The select statement passed as the second parameter is a compound SELECT
+** with an ORDER BY clause. This function allocates and returns a KeyInfo
+** structure suitable for implementing the ORDER BY.
+**
+** Space to hold the KeyInfo structure is obtained from malloc. The calling
+** function is responsible for ensuring that this structure is eventually
+** freed.
+*/
+static KeyInfo *multiSelectOrderByKeyInfo(Parse *pParse, Select *p, int nExtra){
+  ExprList *pOrderBy = p->pOrderBy;
+  int nOrderBy = ALWAYS(pOrderBy!=0) ? pOrderBy->nExpr : 0;
+  sqlite3 *db = pParse->db;
+  KeyInfo *pRet = sqlite3KeyInfoAlloc(db, nOrderBy+nExtra, 1);
+  if( pRet ){
+    int i;
+    for(i=0; i<nOrderBy; i++){
+      struct ExprList_item *pItem = &pOrderBy->a[i];
+      Expr *pTerm = pItem->pExpr;
+      CollSeq *pColl;
+
+      if( pTerm->flags & EP_Collate ){
+        pColl = sqlite3ExprCollSeq(pParse, pTerm);
+      }else{
+        pColl = multiSelectCollSeq(pParse, p, pItem->u.x.iOrderByCol-1);
+        if( pColl==0 ) pColl = db->pDfltColl;
+        pOrderBy->a[i].pExpr =
+          sqlite3ExprAddCollateString(pParse, pTerm, pColl->zName);
+      }
+      assert( sqlite3KeyInfoIsWriteable(pRet) );
+      pRet->aColl[i] = pColl;
+      pRet->aSortFlags[i] = pOrderBy->a[i].fg.sortFlags;
+    }
+  }
+
+  return pRet;
+}
+
+#ifndef SQLITE_OMIT_CTE
+/*
+** This routine generates VDBE code to compute the content of a WITH RECURSIVE
+** query of the form:
+**
+**   <recursive-table> AS (<setup-query> UNION [ALL] <recursive-query>)
+**                         \___________/             \_______________/
+**                           p->pPrior                      p
+**
+**
+** There is exactly one reference to the recursive-table in the FROM clause
+** of recursive-query, marked with the SrcList->a[].fg.isRecursive flag.
+**
+** The setup-query runs once to generate an initial set of rows that go
+** into a Queue table.  Rows are extracted from the Queue table one by
+** one.  Each row extracted from Queue is output to pDest.  Then the single
+** extracted row (now in the iCurrent table) becomes the content of the
+** recursive-table for a recursive-query run.  The output of the recursive-query
+** is added back into the Queue table.  Then another row is extracted from Queue
+** and the iteration continues until the Queue table is empty.
+**
+** If the compound query operator is UNION then no duplicate rows are ever
+** inserted into the Queue table.  The iDistinct table keeps a copy of all rows
+** that have ever been inserted into Queue and causes duplicates to be
+** discarded.  If the operator is UNION ALL, then duplicates are allowed.
+**
+** If the query has an ORDER BY, then entries in the Queue table are kept in
+** ORDER BY order and the first entry is extracted for each cycle.  Without
+** an ORDER BY, the Queue table is just a FIFO.
+**
+** If a LIMIT clause is provided, then the iteration stops after LIMIT rows
+** have been output to pDest.  A LIMIT of zero means to output no rows and a
+** negative LIMIT means to output all rows.  If there is also an OFFSET clause
+** with a positive value, then the first OFFSET outputs are discarded rather
+** than being sent to pDest.  The LIMIT count does not begin until after OFFSET
+** rows have been skipped.
+*/
+static void generateWithRecursiveQuery(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The recursive SELECT to be coded */
+  SelectDest *pDest     /* What to do with query results */
+){
+  SrcList *pSrc = p->pSrc;      /* The FROM clause of the recursive query */
+  int nCol = p->pEList->nExpr;  /* Number of columns in the recursive table */
+  Vdbe *v = pParse->pVdbe;      /* The prepared statement under construction */
+  Select *pSetup;               /* The setup query */
+  Select *pFirstRec;            /* Left-most recursive term */
+  int addrTop;                  /* Top of the loop */
+  int addrCont, addrBreak;      /* CONTINUE and BREAK addresses */
+  int iCurrent = 0;             /* The Current table */
+  int regCurrent;               /* Register holding Current table */
+  int iQueue;                   /* The Queue table */
+  int iDistinct = 0;            /* To ensure unique results if UNION */
+  int eDest = SRT_Fifo;         /* How to write to Queue */
+  SelectDest destQueue;         /* SelectDest targeting the Queue table */
+  int i;                        /* Loop counter */
+  int rc;                       /* Result code */
+  ExprList *pOrderBy;           /* The ORDER BY clause */
+  Expr *pLimit;                 /* Saved LIMIT and OFFSET */
+  int regLimit, regOffset;      /* Registers used by LIMIT and OFFSET */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( p->pWin ){
+    sqlite3ErrorMsg(pParse, "cannot use window functions in recursive queries");
+    return;
+  }
+#endif
+
+  /* Obtain authorization to do a recursive query */
+  if( sqlite3AuthCheck(pParse, SQLITE_RECURSIVE, 0, 0, 0) ) return;
+
+  /* Process the LIMIT and OFFSET clauses, if they exist */
+  addrBreak = sqlite3VdbeMakeLabel(pParse);
+  p->nSelectRow = 320;  /* 4 billion rows */
+  computeLimitRegisters(pParse, p, addrBreak);
+  pLimit = p->pLimit;
+  regLimit = p->iLimit;
+  regOffset = p->iOffset;
+  p->pLimit = 0;
+  p->iLimit = p->iOffset = 0;
+  pOrderBy = p->pOrderBy;
+
+  /* Locate the cursor number of the Current table */
+  for(i=0; ALWAYS(i<pSrc->nSrc); i++){
+    if( pSrc->a[i].fg.isRecursive ){
+      iCurrent = pSrc->a[i].iCursor;
+      break;
+    }
+  }
+
+  /* Allocate cursors numbers for Queue and Distinct.  The cursor number for
+  ** the Distinct table must be exactly one greater than Queue in order
+  ** for the SRT_DistFifo and SRT_DistQueue destinations to work. */
+  iQueue = pParse->nTab++;
+  if( p->op==TK_UNION ){
+    eDest = pOrderBy ? SRT_DistQueue : SRT_DistFifo;
+    iDistinct = pParse->nTab++;
+  }else{
+    eDest = pOrderBy ? SRT_Queue : SRT_Fifo;
+  }
+  sqlite3SelectDestInit(&destQueue, eDest, iQueue);
+
+  /* Allocate cursors for Current, Queue, and Distinct. */
+  regCurrent = ++pParse->nMem;
+  sqlite3VdbeAddOp3(v, OP_OpenPseudo, iCurrent, regCurrent, nCol);
+  if( pOrderBy ){
+    KeyInfo *pKeyInfo = multiSelectOrderByKeyInfo(pParse, p, 1);
+    sqlite3VdbeAddOp4(v, OP_OpenEphemeral, iQueue, pOrderBy->nExpr+2, 0,
+                      (char*)pKeyInfo, P4_KEYINFO);
+    destQueue.pOrderBy = pOrderBy;
+  }else{
+    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iQueue, nCol);
+  }
+  VdbeComment((v, "Queue table"));
+  if( iDistinct ){
+    p->addrOpenEphm[0] = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iDistinct, 0);
+    p->selFlags |= SF_UsesEphemeral;
+  }
+
+  /* Detach the ORDER BY clause from the compound SELECT */
+  p->pOrderBy = 0;
+
+  /* Figure out how many elements of the compound SELECT are part of the
+  ** recursive query.  Make sure no recursive elements use aggregate
+  ** functions.  Mark the recursive elements as UNION ALL even if they
+  ** are really UNION because the distinctness will be enforced by the
+  ** iDistinct table.  pFirstRec is left pointing to the left-most
+  ** recursive term of the CTE.
+  */
+  for(pFirstRec=p; ALWAYS(pFirstRec!=0); pFirstRec=pFirstRec->pPrior){
+    if( pFirstRec->selFlags & SF_Aggregate ){
+      sqlite3ErrorMsg(pParse, "recursive aggregate queries not supported");
+      goto end_of_recursive_query;
+    }
+    pFirstRec->op = TK_ALL;
+    if( (pFirstRec->pPrior->selFlags & SF_Recursive)==0 ) break;
+  }
+
+  /* Store the results of the setup-query in Queue. */
+  pSetup = pFirstRec->pPrior;
+  pSetup->pNext = 0;
+  ExplainQueryPlan((pParse, 1, "SETUP"));
+  rc = sqlite3Select(pParse, pSetup, &destQueue);
+  pSetup->pNext = p;
+  if( rc ) goto end_of_recursive_query;
+
+  /* Find the next row in the Queue and output that row */
+  addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iQueue, addrBreak); VdbeCoverage(v);
+
+  /* Transfer the next row in Queue over to Current */
+  sqlite3VdbeAddOp1(v, OP_NullRow, iCurrent); /* To reset column cache */
+  if( pOrderBy ){
+    sqlite3VdbeAddOp3(v, OP_Column, iQueue, pOrderBy->nExpr+1, regCurrent);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_RowData, iQueue, regCurrent);
+  }
+  sqlite3VdbeAddOp1(v, OP_Delete, iQueue);
+
+  /* Output the single row in Current */
+  addrCont = sqlite3VdbeMakeLabel(pParse);
+  codeOffset(v, regOffset, addrCont);
+  selectInnerLoop(pParse, p, iCurrent,
+      0, 0, pDest, addrCont, addrBreak);
+  if( regLimit ){
+    sqlite3VdbeAddOp2(v, OP_DecrJumpZero, regLimit, addrBreak);
+    VdbeCoverage(v);
+  }
+  sqlite3VdbeResolveLabel(v, addrCont);
+
+  /* Execute the recursive SELECT taking the single row in Current as
+  ** the value for the recursive-table. Store the results in the Queue.
+  */
+  pFirstRec->pPrior = 0;
+  ExplainQueryPlan((pParse, 1, "RECURSIVE STEP"));
+  sqlite3Select(pParse, p, &destQueue);
+  assert( pFirstRec->pPrior==0 );
+  pFirstRec->pPrior = pSetup;
+
+  /* Keep running the loop until the Queue is empty */
+  sqlite3VdbeGoto(v, addrTop);
+  sqlite3VdbeResolveLabel(v, addrBreak);
+
+end_of_recursive_query:
+  sqlite3ExprListDelete(pParse->db, p->pOrderBy);
+  p->pOrderBy = pOrderBy;
+  p->pLimit = pLimit;
+  return;
+}
+#endif /* SQLITE_OMIT_CTE */
+
+/* Forward references */
+static int multiSelectOrderBy(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The right-most of SELECTs to be coded */
+  SelectDest *pDest     /* What to do with query results */
+);
+
+/*
+** Handle the special case of a compound-select that originates from a
+** VALUES clause.  By handling this as a special case, we avoid deep
+** recursion, and thus do not need to enforce the SQLITE_LIMIT_COMPOUND_SELECT
+** on a VALUES clause.
+**
+** Because the Select object originates from a VALUES clause:
+**   (1) There is no LIMIT or OFFSET or else there is a LIMIT of exactly 1
+**   (2) All terms are UNION ALL
+**   (3) There is no ORDER BY clause
+**
+** The "LIMIT of exactly 1" case of condition (1) comes about when a VALUES
+** clause occurs within scalar expression (ex: "SELECT (VALUES(1),(2),(3))").
+** The sqlite3CodeSubselect will have added the LIMIT 1 clause in tht case.
+** Since the limit is exactly 1, we only need to evaluate the left-most VALUES.
+*/
+static int multiSelectValues(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The right-most of SELECTs to be coded */
+  SelectDest *pDest     /* What to do with query results */
+){
+  int nRow = 1;
+  int rc = 0;
+  int bShowAll = p->pLimit==0;
+  assert( p->selFlags & SF_MultiValue );
+  do{
+    assert( p->selFlags & SF_Values );
+    assert( p->op==TK_ALL || (p->op==TK_SELECT && p->pPrior==0) );
+    assert( p->pNext==0 || p->pEList->nExpr==p->pNext->pEList->nExpr );
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( p->pWin ) return -1;
+#endif
+    if( p->pPrior==0 ) break;
+    assert( p->pPrior->pNext==p );
+    p = p->pPrior;
+    nRow += bShowAll;
+  }while(1);
+  ExplainQueryPlan((pParse, 0, "SCAN %d CONSTANT ROW%s", nRow,
+                    nRow==1 ? "" : "S"));
+  while( p ){
+    selectInnerLoop(pParse, p, -1, 0, 0, pDest, 1, 1);
+    if( !bShowAll ) break;
+    p->nSelectRow = nRow;
+    p = p->pNext;
+  }
+  return rc;
+}
+
+/*
+** Return true if the SELECT statement which is known to be the recursive
+** part of a recursive CTE still has its anchor terms attached.  If the
+** anchor terms have already been removed, then return false.
+*/
+static int hasAnchor(Select *p){
+  while( p && (p->selFlags & SF_Recursive)!=0 ){ p = p->pPrior; }
+  return p!=0;
+}
+
+/*
+** This routine is called to process a compound query form from
+** two or more separate queries using UNION, UNION ALL, EXCEPT, or
+** INTERSECT
+**
+** "p" points to the right-most of the two queries.  the query on the
+** left is p->pPrior.  The left query could also be a compound query
+** in which case this routine will be called recursively.
+**
+** The results of the total query are to be written into a destination
+** of type eDest with parameter iParm.
+**
+** Example 1:  Consider a three-way compound SQL statement.
+**
+**     SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
+**
+** This statement is parsed up as follows:
+**
+**     SELECT c FROM t3
+**      |
+**      `----->  SELECT b FROM t2
+**                |
+**                `------>  SELECT a FROM t1
+**
+** The arrows in the diagram above represent the Select.pPrior pointer.
+** So if this routine is called with p equal to the t3 query, then
+** pPrior will be the t2 query.  p->op will be TK_UNION in this case.
+**
+** Notice that because of the way SQLite parses compound SELECTs, the
+** individual selects always group from left to right.
+*/
+static int multiSelect(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The right-most of SELECTs to be coded */
+  SelectDest *pDest     /* What to do with query results */
+){
+  int rc = SQLITE_OK;   /* Success code from a subroutine */
+  Select *pPrior;       /* Another SELECT immediately to our left */
+  Vdbe *v;              /* Generate code to this VDBE */
+  SelectDest dest;      /* Alternative data destination */
+  Select *pDelete = 0;  /* Chain of simple selects to delete */
+  sqlite3 *db;          /* Database connection */
+
+  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
+  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
+  */
+  assert( p && p->pPrior );  /* Calling function guarantees this much */
+  assert( (p->selFlags & SF_Recursive)==0 || p->op==TK_ALL || p->op==TK_UNION );
+  assert( p->selFlags & SF_Compound );
+  db = pParse->db;
+  pPrior = p->pPrior;
+  dest = *pDest;
+  assert( pPrior->pOrderBy==0 );
+  assert( pPrior->pLimit==0 );
+
+  v = sqlite3GetVdbe(pParse);
+  assert( v!=0 );  /* The VDBE already created by calling function */
+
+  /* Create the destination temporary table if necessary
+  */
+  if( dest.eDest==SRT_EphemTab ){
+    assert( p->pEList );
+    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iSDParm, p->pEList->nExpr);
+    dest.eDest = SRT_Table;
+  }
+
+  /* Special handling for a compound-select that originates as a VALUES clause.
+  */
+  if( p->selFlags & SF_MultiValue ){
+    rc = multiSelectValues(pParse, p, &dest);
+    if( rc>=0 ) goto multi_select_end;
+    rc = SQLITE_OK;
+  }
+
+  /* Make sure all SELECTs in the statement have the same number of elements
+  ** in their result sets.
+  */
+  assert( p->pEList && pPrior->pEList );
+  assert( p->pEList->nExpr==pPrior->pEList->nExpr );
+
+#ifndef SQLITE_OMIT_CTE
+  if( (p->selFlags & SF_Recursive)!=0 && hasAnchor(p) ){
+    generateWithRecursiveQuery(pParse, p, &dest);
+  }else
+#endif
+
+  /* Compound SELECTs that have an ORDER BY clause are handled separately.
+  */
+  if( p->pOrderBy ){
+    return multiSelectOrderBy(pParse, p, pDest);
+  }else{
+
+#ifndef SQLITE_OMIT_EXPLAIN
+    if( pPrior->pPrior==0 ){
+      ExplainQueryPlan((pParse, 1, "COMPOUND QUERY"));
+      ExplainQueryPlan((pParse, 1, "LEFT-MOST SUBQUERY"));
+    }
+#endif
+
+    /* Generate code for the left and right SELECT statements.
+    */
+    switch( p->op ){
+      case TK_ALL: {
+        int addr = 0;
+        int nLimit = 0;  /* Initialize to suppress harmless compiler warning */
+        assert( !pPrior->pLimit );
+        pPrior->iLimit = p->iLimit;
+        pPrior->iOffset = p->iOffset;
+        pPrior->pLimit = p->pLimit;
+        TREETRACE(0x200, pParse, p, ("multiSelect UNION ALL left...\n"));
+        rc = sqlite3Select(pParse, pPrior, &dest);
+        pPrior->pLimit = 0;
+        if( rc ){
+          goto multi_select_end;
+        }
+        p->pPrior = 0;
+        p->iLimit = pPrior->iLimit;
+        p->iOffset = pPrior->iOffset;
+        if( p->iLimit ){
+          addr = sqlite3VdbeAddOp1(v, OP_IfNot, p->iLimit); VdbeCoverage(v);
+          VdbeComment((v, "Jump ahead if LIMIT reached"));
+          if( p->iOffset ){
+            sqlite3VdbeAddOp3(v, OP_OffsetLimit,
+                              p->iLimit, p->iOffset+1, p->iOffset);
+          }
+        }
+        ExplainQueryPlan((pParse, 1, "UNION ALL"));
+        TREETRACE(0x200, pParse, p, ("multiSelect UNION ALL right...\n"));
+        rc = sqlite3Select(pParse, p, &dest);
+        testcase( rc!=SQLITE_OK );
+        pDelete = p->pPrior;
+        p->pPrior = pPrior;
+        p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
+        if( p->pLimit
+         && sqlite3ExprIsInteger(p->pLimit->pLeft, &nLimit, pParse)
+         && nLimit>0 && p->nSelectRow > sqlite3LogEst((u64)nLimit)
+        ){
+          p->nSelectRow = sqlite3LogEst((u64)nLimit);
+        }
+        if( addr ){
+          sqlite3VdbeJumpHere(v, addr);
+        }
+        break;
+      }
+      case TK_EXCEPT:
+      case TK_UNION: {
+        int unionTab;    /* Cursor number of the temp table holding result */
+        u8 op = 0;       /* One of the SRT_ operations to apply to self */
+        int priorOp;     /* The SRT_ operation to apply to prior selects */
+        Expr *pLimit;    /* Saved values of p->nLimit  */
+        int addr;
+        SelectDest uniondest;
+
+        testcase( p->op==TK_EXCEPT );
+        testcase( p->op==TK_UNION );
+        priorOp = SRT_Union;
+        if( dest.eDest==priorOp ){
+          /* We can reuse a temporary table generated by a SELECT to our
+          ** right.
+          */
+          assert( p->pLimit==0 );      /* Not allowed on leftward elements */
+          unionTab = dest.iSDParm;
+        }else{
+          /* We will need to create our own temporary table to hold the
+          ** intermediate results.
+          */
+          unionTab = pParse->nTab++;
+          assert( p->pOrderBy==0 );
+          addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
+          assert( p->addrOpenEphm[0] == -1 );
+          p->addrOpenEphm[0] = addr;
+          findRightmost(p)->selFlags |= SF_UsesEphemeral;
+          assert( p->pEList );
+        }
+
+
+        /* Code the SELECT statements to our left
+        */
+        assert( !pPrior->pOrderBy );
+        sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
+        TREETRACE(0x200, pParse, p, ("multiSelect EXCEPT/UNION left...\n"));
+        rc = sqlite3Select(pParse, pPrior, &uniondest);
+        if( rc ){
+          goto multi_select_end;
+        }
+
+        /* Code the current SELECT statement
+        */
+        if( p->op==TK_EXCEPT ){
+          op = SRT_Except;
+        }else{
+          assert( p->op==TK_UNION );
+          op = SRT_Union;
+        }
+        p->pPrior = 0;
+        pLimit = p->pLimit;
+        p->pLimit = 0;
+        uniondest.eDest = op;
+        ExplainQueryPlan((pParse, 1, "%s USING TEMP B-TREE",
+                          sqlite3SelectOpName(p->op)));
+        TREETRACE(0x200, pParse, p, ("multiSelect EXCEPT/UNION right...\n"));
+        rc = sqlite3Select(pParse, p, &uniondest);
+        testcase( rc!=SQLITE_OK );
+        assert( p->pOrderBy==0 );
+        pDelete = p->pPrior;
+        p->pPrior = pPrior;
+        p->pOrderBy = 0;
+        if( p->op==TK_UNION ){
+          p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
+        }
+        sqlite3ExprDelete(db, p->pLimit);
+        p->pLimit = pLimit;
+        p->iLimit = 0;
+        p->iOffset = 0;
+
+        /* Convert the data in the temporary table into whatever form
+        ** it is that we currently need.
+        */
+        assert( unionTab==dest.iSDParm || dest.eDest!=priorOp );
+        assert( p->pEList || db->mallocFailed );
+        if( dest.eDest!=priorOp && db->mallocFailed==0 ){
+          int iCont, iBreak, iStart;
+          iBreak = sqlite3VdbeMakeLabel(pParse);
+          iCont = sqlite3VdbeMakeLabel(pParse);
+          computeLimitRegisters(pParse, p, iBreak);
+          sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak); VdbeCoverage(v);
+          iStart = sqlite3VdbeCurrentAddr(v);
+          selectInnerLoop(pParse, p, unionTab,
+                          0, 0, &dest, iCont, iBreak);
+          sqlite3VdbeResolveLabel(v, iCont);
+          sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart); VdbeCoverage(v);
+          sqlite3VdbeResolveLabel(v, iBreak);
+          sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0);
+        }
+        break;
+      }
+      default: assert( p->op==TK_INTERSECT ); {
+        int tab1, tab2;
+        int iCont, iBreak, iStart;
+        Expr *pLimit;
+        int addr;
+        SelectDest intersectdest;
+        int r1;
+
+        /* INTERSECT is different from the others since it requires
+        ** two temporary tables.  Hence it has its own case.  Begin
+        ** by allocating the tables we will need.
+        */
+        tab1 = pParse->nTab++;
+        tab2 = pParse->nTab++;
+        assert( p->pOrderBy==0 );
+
+        addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
+        assert( p->addrOpenEphm[0] == -1 );
+        p->addrOpenEphm[0] = addr;
+        findRightmost(p)->selFlags |= SF_UsesEphemeral;
+        assert( p->pEList );
+
+        /* Code the SELECTs to our left into temporary table "tab1".
+        */
+        sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
+        TREETRACE(0x400, pParse, p, ("multiSelect INTERSECT left...\n"));
+        rc = sqlite3Select(pParse, pPrior, &intersectdest);
+        if( rc ){
+          goto multi_select_end;
+        }
+
+        /* Code the current SELECT into temporary table "tab2"
+        */
+        addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0);
+        assert( p->addrOpenEphm[1] == -1 );
+        p->addrOpenEphm[1] = addr;
+        p->pPrior = 0;
+        pLimit = p->pLimit;
+        p->pLimit = 0;
+        intersectdest.iSDParm = tab2;
+        ExplainQueryPlan((pParse, 1, "%s USING TEMP B-TREE",
+                          sqlite3SelectOpName(p->op)));
+        TREETRACE(0x400, pParse, p, ("multiSelect INTERSECT right...\n"));
+        rc = sqlite3Select(pParse, p, &intersectdest);
+        testcase( rc!=SQLITE_OK );
+        pDelete = p->pPrior;
+        p->pPrior = pPrior;
+        if( p->nSelectRow>pPrior->nSelectRow ){
+          p->nSelectRow = pPrior->nSelectRow;
+        }
+        sqlite3ExprDelete(db, p->pLimit);
+        p->pLimit = pLimit;
+
+        /* Generate code to take the intersection of the two temporary
+        ** tables.
+        */
+        if( rc ) break;
+        assert( p->pEList );
+        iBreak = sqlite3VdbeMakeLabel(pParse);
+        iCont = sqlite3VdbeMakeLabel(pParse);
+        computeLimitRegisters(pParse, p, iBreak);
+        sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak); VdbeCoverage(v);
+        r1 = sqlite3GetTempReg(pParse);
+        iStart = sqlite3VdbeAddOp2(v, OP_RowData, tab1, r1);
+        sqlite3VdbeAddOp4Int(v, OP_NotFound, tab2, iCont, r1, 0);
+        VdbeCoverage(v);
+        sqlite3ReleaseTempReg(pParse, r1);
+        selectInnerLoop(pParse, p, tab1,
+                        0, 0, &dest, iCont, iBreak);
+        sqlite3VdbeResolveLabel(v, iCont);
+        sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart); VdbeCoverage(v);
+        sqlite3VdbeResolveLabel(v, iBreak);
+        sqlite3VdbeAddOp2(v, OP_Close, tab2, 0);
+        sqlite3VdbeAddOp2(v, OP_Close, tab1, 0);
+        break;
+      }
+    }
+
+  #ifndef SQLITE_OMIT_EXPLAIN
+    if( p->pNext==0 ){
+      ExplainQueryPlanPop(pParse);
+    }
+  #endif
+  }
+  if( pParse->nErr ) goto multi_select_end;
+
+  /* Compute collating sequences used by
+  ** temporary tables needed to implement the compound select.
+  ** Attach the KeyInfo structure to all temporary tables.
+  **
+  ** This section is run by the right-most SELECT statement only.
+  ** SELECT statements to the left always skip this part.  The right-most
+  ** SELECT might also skip this part if it has no ORDER BY clause and
+  ** no temp tables are required.
+  */
+  if( p->selFlags & SF_UsesEphemeral ){
+    int i;                        /* Loop counter */
+    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
+    Select *pLoop;                /* For looping through SELECT statements */
+    CollSeq **apColl;             /* For looping through pKeyInfo->aColl[] */
+    int nCol;                     /* Number of columns in result set */
+
+    assert( p->pNext==0 );
+    assert( p->pEList!=0 );
+    nCol = p->pEList->nExpr;
+    pKeyInfo = sqlite3KeyInfoAlloc(db, nCol, 1);
+    if( !pKeyInfo ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto multi_select_end;
+    }
+    for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
+      *apColl = multiSelectCollSeq(pParse, p, i);
+      if( 0==*apColl ){
+        *apColl = db->pDfltColl;
+      }
+    }
+
+    for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
+      for(i=0; i<2; i++){
+        int addr = pLoop->addrOpenEphm[i];
+        if( addr<0 ){
+          /* If [0] is unused then [1] is also unused.  So we can
+          ** always safely abort as soon as the first unused slot is found */
+          assert( pLoop->addrOpenEphm[1]<0 );
+          break;
+        }
+        sqlite3VdbeChangeP2(v, addr, nCol);
+        sqlite3VdbeChangeP4(v, addr, (char*)sqlite3KeyInfoRef(pKeyInfo),
+                            P4_KEYINFO);
+        pLoop->addrOpenEphm[i] = -1;
+      }
+    }
+    sqlite3KeyInfoUnref(pKeyInfo);
+  }
+
+multi_select_end:
+  pDest->iSdst = dest.iSdst;
+  pDest->nSdst = dest.nSdst;
+  pDest->iSDParm2 = dest.iSDParm2;
+  if( pDelete ){
+    sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pDelete);
+  }
+  return rc;
+}
+#endif /* SQLITE_OMIT_COMPOUND_SELECT */
+
+/*
+** Error message for when two or more terms of a compound select have different
+** size result sets.
+*/
+SQLITE_PRIVATE void sqlite3SelectWrongNumTermsError(Parse *pParse, Select *p){
+  if( p->selFlags & SF_Values ){
+    sqlite3ErrorMsg(pParse, "all VALUES must have the same number of terms");
+  }else{
+    sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
+      " do not have the same number of result columns",
+      sqlite3SelectOpName(p->op));
+  }
+}
+
+/*
+** Code an output subroutine for a coroutine implementation of a
+** SELECT statement.
+**
+** The data to be output is contained in pIn->iSdst.  There are
+** pIn->nSdst columns to be output.  pDest is where the output should
+** be sent.
+**
+** regReturn is the number of the register holding the subroutine
+** return address.
+**
+** If regPrev>0 then it is the first register in a vector that
+** records the previous output.  mem[regPrev] is a flag that is false
+** if there has been no previous output.  If regPrev>0 then code is
+** generated to suppress duplicates.  pKeyInfo is used for comparing
+** keys.
+**
+** If the LIMIT found in p->iLimit is reached, jump immediately to
+** iBreak.
+*/
+static int generateOutputSubroutine(
+  Parse *pParse,          /* Parsing context */
+  Select *p,              /* The SELECT statement */
+  SelectDest *pIn,        /* Coroutine supplying data */
+  SelectDest *pDest,      /* Where to send the data */
+  int regReturn,          /* The return address register */
+  int regPrev,            /* Previous result register.  No uniqueness if 0 */
+  KeyInfo *pKeyInfo,      /* For comparing with previous entry */
+  int iBreak              /* Jump here if we hit the LIMIT */
+){
+  Vdbe *v = pParse->pVdbe;
+  int iContinue;
+  int addr;
+
+  addr = sqlite3VdbeCurrentAddr(v);
+  iContinue = sqlite3VdbeMakeLabel(pParse);
+
+  /* Suppress duplicates for UNION, EXCEPT, and INTERSECT
+  */
+  if( regPrev ){
+    int addr1, addr2;
+    addr1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev); VdbeCoverage(v);
+    addr2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iSdst, regPrev+1, pIn->nSdst,
+                              (char*)sqlite3KeyInfoRef(pKeyInfo), P4_KEYINFO);
+    sqlite3VdbeAddOp3(v, OP_Jump, addr2+2, iContinue, addr2+2); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr1);
+    sqlite3VdbeAddOp3(v, OP_Copy, pIn->iSdst, regPrev+1, pIn->nSdst-1);
+    sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
+  }
+  if( pParse->db->mallocFailed ) return 0;
+
+  /* Suppress the first OFFSET entries if there is an OFFSET clause
+  */
+  codeOffset(v, p->iOffset, iContinue);
+
+  assert( pDest->eDest!=SRT_Exists );
+  assert( pDest->eDest!=SRT_Table );
+  switch( pDest->eDest ){
+    /* Store the result as data using a unique key.
+    */
+    case SRT_EphemTab: {
+      int r1 = sqlite3GetTempReg(pParse);
+      int r2 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iSdst, pIn->nSdst, r1);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iSDParm, r2);
+      sqlite3VdbeAddOp3(v, OP_Insert, pDest->iSDParm, r1, r2);
+      sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
+      sqlite3ReleaseTempReg(pParse, r2);
+      sqlite3ReleaseTempReg(pParse, r1);
+      break;
+    }
+
+#ifndef SQLITE_OMIT_SUBQUERY
+    /* If we are creating a set for an "expr IN (SELECT ...)".
+    */
+    case SRT_Set: {
+      int r1;
+      testcase( pIn->nSdst>1 );
+      r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iSdst, pIn->nSdst,
+          r1, pDest->zAffSdst, pIn->nSdst);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pDest->iSDParm, r1,
+                           pIn->iSdst, pIn->nSdst);
+      if( pDest->iSDParm2>0 ){
+        sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pDest->iSDParm2, 0,
+                             pIn->iSdst, pIn->nSdst);
+        ExplainQueryPlan((pParse, 0, "CREATE BLOOM FILTER"));
+      }
+      sqlite3ReleaseTempReg(pParse, r1);
+      break;
+    }
+
+    /* If this is a scalar select that is part of an expression, then
+    ** store the results in the appropriate memory cell and break out
+    ** of the scan loop.  Note that the select might return multiple columns
+    ** if it is the RHS of a row-value IN operator.
+    */
+    case SRT_Mem: {
+      testcase( pIn->nSdst>1 );
+      sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSDParm, pIn->nSdst);
+      /* The LIMIT clause will jump out of the loop for us */
+      break;
+    }
+#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
+
+    /* The results are stored in a sequence of registers
+    ** starting at pDest->iSdst.  Then the co-routine yields.
+    */
+    case SRT_Coroutine: {
+      if( pDest->iSdst==0 ){
+        pDest->iSdst = sqlite3GetTempRange(pParse, pIn->nSdst);
+        pDest->nSdst = pIn->nSdst;
+      }
+      sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSdst, pIn->nSdst);
+      sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
+      break;
+    }
+
+    /* If none of the above, then the result destination must be
+    ** SRT_Output.  This routine is never called with any other
+    ** destination other than the ones handled above or SRT_Output.
+    **
+    ** For SRT_Output, results are stored in a sequence of registers.
+    ** Then the OP_ResultRow opcode is used to cause sqlite3_step() to
+    ** return the next row of result.
+    */
+    default: {
+      assert( pDest->eDest==SRT_Output );
+      sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iSdst, pIn->nSdst);
+      break;
+    }
+  }
+
+  /* Jump to the end of the loop if the LIMIT is reached.
+  */
+  if( p->iLimit ){
+    sqlite3VdbeAddOp2(v, OP_DecrJumpZero, p->iLimit, iBreak); VdbeCoverage(v);
+  }
+
+  /* Generate the subroutine return
+  */
+  sqlite3VdbeResolveLabel(v, iContinue);
+  sqlite3VdbeAddOp1(v, OP_Return, regReturn);
+
+  return addr;
+}
+
+/*
+** Alternative compound select code generator for cases when there
+** is an ORDER BY clause.
+**
+** We assume a query of the following form:
+**
+**      <selectA>  <operator>  <selectB>  ORDER BY <orderbylist>
+**
+** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT.  The idea
+** is to code both <selectA> and <selectB> with the ORDER BY clause as
+** co-routines.  Then run the co-routines in parallel and merge the results
+** into the output.  In addition to the two coroutines (called selectA and
+** selectB) there are 7 subroutines:
+**
+**    outA:    Move the output of the selectA coroutine into the output
+**             of the compound query.
+**
+**    outB:    Move the output of the selectB coroutine into the output
+**             of the compound query.  (Only generated for UNION and
+**             UNION ALL.  EXCEPT and INSERTSECT never output a row that
+**             appears only in B.)
+**
+**    AltB:    Called when there is data from both coroutines and A<B.
+**
+**    AeqB:    Called when there is data from both coroutines and A==B.
+**
+**    AgtB:    Called when there is data from both coroutines and A>B.
+**
+**    EofA:    Called when data is exhausted from selectA.
+**
+**    EofB:    Called when data is exhausted from selectB.
+**
+** The implementation of the latter five subroutines depend on which
+** <operator> is used:
+**
+**
+**             UNION ALL         UNION            EXCEPT          INTERSECT
+**          -------------  -----------------  --------------  -----------------
+**   AltB:   outA, nextA      outA, nextA       outA, nextA         nextA
+**
+**   AeqB:   outA, nextA         nextA             nextA         outA, nextA
+**
+**   AgtB:   outB, nextB      outB, nextB          nextB            nextB
+**
+**   EofA:   outB, nextB      outB, nextB          halt             halt
+**
+**   EofB:   outA, nextA      outA, nextA       outA, nextA         halt
+**
+** In the AltB, AeqB, and AgtB subroutines, an EOF on A following nextA
+** causes an immediate jump to EofA and an EOF on B following nextB causes
+** an immediate jump to EofB.  Within EofA and EofB, and EOF on entry or
+** following nextX causes a jump to the end of the select processing.
+**
+** Duplicate removal in the UNION, EXCEPT, and INTERSECT cases is handled
+** within the output subroutine.  The regPrev register set holds the previously
+** output value.  A comparison is made against this value and the output
+** is skipped if the next results would be the same as the previous.
+**
+** The implementation plan is to implement the two coroutines and seven
+** subroutines first, then put the control logic at the bottom.  Like this:
+**
+**          goto Init
+**     coA: coroutine for left query (A)
+**     coB: coroutine for right query (B)
+**    outA: output one row of A
+**    outB: output one row of B (UNION and UNION ALL only)
+**    EofA: ...
+**    EofB: ...
+**    AltB: ...
+**    AeqB: ...
+**    AgtB: ...
+**    Init: initialize coroutine registers
+**          yield coA
+**          if eof(A) goto EofA
+**          yield coB
+**          if eof(B) goto EofB
+**    Cmpr: Compare A, B
+**          Jump AltB, AeqB, AgtB
+**     End: ...
+**
+** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not
+** actually called using Gosub and they do not Return.  EofA and EofB loop
+** until all data is exhausted then jump to the "end" label.  AltB, AeqB,
+** and AgtB jump to either L2 or to one of EofA or EofB.
+*/
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+static int multiSelectOrderBy(
+  Parse *pParse,        /* Parsing context */
+  Select *p,            /* The right-most of SELECTs to be coded */
+  SelectDest *pDest     /* What to do with query results */
+){
+  int i, j;             /* Loop counters */
+  Select *pPrior;       /* Another SELECT immediately to our left */
+  Select *pSplit;       /* Left-most SELECT in the right-hand group */
+  int nSelect;          /* Number of SELECT statements in the compound */
+  Vdbe *v;              /* Generate code to this VDBE */
+  SelectDest destA;     /* Destination for coroutine A */
+  SelectDest destB;     /* Destination for coroutine B */
+  int regAddrA;         /* Address register for select-A coroutine */
+  int regAddrB;         /* Address register for select-B coroutine */
+  int addrSelectA;      /* Address of the select-A coroutine */
+  int addrSelectB;      /* Address of the select-B coroutine */
+  int regOutA;          /* Address register for the output-A subroutine */
+  int regOutB;          /* Address register for the output-B subroutine */
+  int addrOutA;         /* Address of the output-A subroutine */
+  int addrOutB = 0;     /* Address of the output-B subroutine */
+  int addrEofA;         /* Address of the select-A-exhausted subroutine */
+  int addrEofA_noB;     /* Alternate addrEofA if B is uninitialized */
+  int addrEofB;         /* Address of the select-B-exhausted subroutine */
+  int addrAltB;         /* Address of the A<B subroutine */
+  int addrAeqB;         /* Address of the A==B subroutine */
+  int addrAgtB;         /* Address of the A>B subroutine */
+  int regLimitA;        /* Limit register for select-A */
+  int regLimitB;        /* Limit register for select-A */
+  int regPrev;          /* A range of registers to hold previous output */
+  int savedLimit;       /* Saved value of p->iLimit */
+  int savedOffset;      /* Saved value of p->iOffset */
+  int labelCmpr;        /* Label for the start of the merge algorithm */
+  int labelEnd;         /* Label for the end of the overall SELECT stmt */
+  int addr1;            /* Jump instructions that get retargeted */
+  int op;               /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
+  KeyInfo *pKeyDup = 0; /* Comparison information for duplicate removal */
+  KeyInfo *pKeyMerge;   /* Comparison information for merging rows */
+  sqlite3 *db;          /* Database connection */
+  ExprList *pOrderBy;   /* The ORDER BY clause */
+  int nOrderBy;         /* Number of terms in the ORDER BY clause */
+  u32 *aPermute;        /* Mapping from ORDER BY terms to result set columns */
+
+  assert( p->pOrderBy!=0 );
+  assert( pKeyDup==0 ); /* "Managed" code needs this.  Ticket #3382. */
+  db = pParse->db;
+  v = pParse->pVdbe;
+  assert( v!=0 );       /* Already thrown the error if VDBE alloc failed */
+  labelEnd = sqlite3VdbeMakeLabel(pParse);
+  labelCmpr = sqlite3VdbeMakeLabel(pParse);
+
+
+  /* Patch up the ORDER BY clause
+  */
+  op = p->op;
+  assert( p->pPrior->pOrderBy==0 );
+  pOrderBy = p->pOrderBy;
+  assert( pOrderBy );
+  nOrderBy = pOrderBy->nExpr;
+
+  /* For operators other than UNION ALL we have to make sure that
+  ** the ORDER BY clause covers every term of the result set.  Add
+  ** terms to the ORDER BY clause as necessary.
+  */
+  if( op!=TK_ALL ){
+    for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){
+      struct ExprList_item *pItem;
+      for(j=0, pItem=pOrderBy->a; j<nOrderBy; j++, pItem++){
+        assert( pItem!=0 );
+        assert( pItem->u.x.iOrderByCol>0 );
+        if( pItem->u.x.iOrderByCol==i ) break;
+      }
+      if( j==nOrderBy ){
+        Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
+        if( pNew==0 ) return SQLITE_NOMEM_BKPT;
+        pNew->flags |= EP_IntValue;
+        pNew->u.iValue = i;
+        p->pOrderBy = pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew);
+        if( pOrderBy ) pOrderBy->a[nOrderBy++].u.x.iOrderByCol = (u16)i;
+      }
+    }
+  }
+
+  /* Compute the comparison permutation and keyinfo that is used with
+  ** the permutation used to determine if the next
+  ** row of results comes from selectA or selectB.  Also add explicit
+  ** collations to the ORDER BY clause terms so that when the subqueries
+  ** to the right and the left are evaluated, they use the correct
+  ** collation.
+  */
+  aPermute = sqlite3DbMallocRawNN(db, sizeof(u32)*(nOrderBy + 1));
+  if( aPermute ){
+    struct ExprList_item *pItem;
+    aPermute[0] = nOrderBy;
+    for(i=1, pItem=pOrderBy->a; i<=nOrderBy; i++, pItem++){
+      assert( pItem!=0 );
+      assert( pItem->u.x.iOrderByCol>0 );
+      assert( pItem->u.x.iOrderByCol<=p->pEList->nExpr );
+      aPermute[i] = pItem->u.x.iOrderByCol - 1;
+    }
+    pKeyMerge = multiSelectOrderByKeyInfo(pParse, p, 1);
+  }else{
+    pKeyMerge = 0;
+  }
+
+  /* Allocate a range of temporary registers and the KeyInfo needed
+  ** for the logic that removes duplicate result rows when the
+  ** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL).
+  */
+  if( op==TK_ALL ){
+    regPrev = 0;
+  }else{
+    int nExpr = p->pEList->nExpr;
+    assert( nOrderBy>=nExpr || db->mallocFailed );
+    regPrev = pParse->nMem+1;
+    pParse->nMem += nExpr+1;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev);
+    pKeyDup = sqlite3KeyInfoAlloc(db, nExpr, 1);
+    if( pKeyDup ){
+      assert( sqlite3KeyInfoIsWriteable(pKeyDup) );
+      for(i=0; i<nExpr; i++){
+        pKeyDup->aColl[i] = multiSelectCollSeq(pParse, p, i);
+        pKeyDup->aSortFlags[i] = 0;
+      }
+    }
+  }
+
+  /* Separate the left and the right query from one another
+  */
+  nSelect = 1;
+  if( (op==TK_ALL || op==TK_UNION)
+   && OptimizationEnabled(db, SQLITE_BalancedMerge)
+  ){
+    for(pSplit=p; pSplit->pPrior!=0 && pSplit->op==op; pSplit=pSplit->pPrior){
+      nSelect++;
+      assert( pSplit->pPrior->pNext==pSplit );
+    }
+  }
+  if( nSelect<=3 ){
+    pSplit = p;
+  }else{
+    pSplit = p;
+    for(i=2; i<nSelect; i+=2){ pSplit = pSplit->pPrior; }
+  }
+  pPrior = pSplit->pPrior;
+  assert( pPrior!=0 );
+  pSplit->pPrior = 0;
+  pPrior->pNext = 0;
+  assert( p->pOrderBy == pOrderBy );
+  assert( pOrderBy!=0 || db->mallocFailed );
+  pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0);
+  sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
+  sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
+
+  /* Compute the limit registers */
+  computeLimitRegisters(pParse, p, labelEnd);
+  if( p->iLimit && op==TK_ALL ){
+    regLimitA = ++pParse->nMem;
+    regLimitB = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit,
+                                  regLimitA);
+    sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB);
+  }else{
+    regLimitA = regLimitB = 0;
+  }
+  sqlite3ExprDelete(db, p->pLimit);
+  p->pLimit = 0;
+
+  regAddrA = ++pParse->nMem;
+  regAddrB = ++pParse->nMem;
+  regOutA = ++pParse->nMem;
+  regOutB = ++pParse->nMem;
+  sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
+  sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);
+
+  ExplainQueryPlan((pParse, 1, "MERGE (%s)", sqlite3SelectOpName(p->op)));
+
+  /* Generate a coroutine to evaluate the SELECT statement to the
+  ** left of the compound operator - the "A" select.
+  */
+  addrSelectA = sqlite3VdbeCurrentAddr(v) + 1;
+  addr1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrA, 0, addrSelectA);
+  VdbeComment((v, "left SELECT"));
+  pPrior->iLimit = regLimitA;
+  ExplainQueryPlan((pParse, 1, "LEFT"));
+  sqlite3Select(pParse, pPrior, &destA);
+  sqlite3VdbeEndCoroutine(v, regAddrA);
+  sqlite3VdbeJumpHere(v, addr1);
+
+  /* Generate a coroutine to evaluate the SELECT statement on
+  ** the right - the "B" select
+  */
+  addrSelectB = sqlite3VdbeCurrentAddr(v) + 1;
+  addr1 = sqlite3VdbeAddOp3(v, OP_InitCoroutine, regAddrB, 0, addrSelectB);
+  VdbeComment((v, "right SELECT"));
+  savedLimit = p->iLimit;
+  savedOffset = p->iOffset;
+  p->iLimit = regLimitB;
+  p->iOffset = 0;
+  ExplainQueryPlan((pParse, 1, "RIGHT"));
+  sqlite3Select(pParse, p, &destB);
+  p->iLimit = savedLimit;
+  p->iOffset = savedOffset;
+  sqlite3VdbeEndCoroutine(v, regAddrB);
+
+  /* Generate a subroutine that outputs the current row of the A
+  ** select as the next output row of the compound select.
+  */
+  VdbeNoopComment((v, "Output routine for A"));
+  addrOutA = generateOutputSubroutine(pParse,
+                 p, &destA, pDest, regOutA,
+                 regPrev, pKeyDup, labelEnd);
+
+  /* Generate a subroutine that outputs the current row of the B
+  ** select as the next output row of the compound select.
+  */
+  if( op==TK_ALL || op==TK_UNION ){
+    VdbeNoopComment((v, "Output routine for B"));
+    addrOutB = generateOutputSubroutine(pParse,
+                 p, &destB, pDest, regOutB,
+                 regPrev, pKeyDup, labelEnd);
+  }
+  sqlite3KeyInfoUnref(pKeyDup);
+
+  /* Generate a subroutine to run when the results from select A
+  ** are exhausted and only data in select B remains.
+  */
+  if( op==TK_EXCEPT || op==TK_INTERSECT ){
+    addrEofA_noB = addrEofA = labelEnd;
+  }else{
+    VdbeNoopComment((v, "eof-A subroutine"));
+    addrEofA = sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
+    addrEofA_noB = sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, labelEnd);
+                                     VdbeCoverage(v);
+    sqlite3VdbeGoto(v, addrEofA);
+    p->nSelectRow = sqlite3LogEstAdd(p->nSelectRow, pPrior->nSelectRow);
+  }
+
+  /* Generate a subroutine to run when the results from select B
+  ** are exhausted and only data in select A remains.
+  */
+  if( op==TK_INTERSECT ){
+    addrEofB = addrEofA;
+    if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
+  }else{
+    VdbeNoopComment((v, "eof-B subroutine"));
+    addrEofB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
+    sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, labelEnd); VdbeCoverage(v);
+    sqlite3VdbeGoto(v, addrEofB);
+  }
+
+  /* Generate code to handle the case of A<B
+  */
+  VdbeNoopComment((v, "A-lt-B subroutine"));
+  addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
+  sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA); VdbeCoverage(v);
+  sqlite3VdbeGoto(v, labelCmpr);
+
+  /* Generate code to handle the case of A==B
+  */
+  if( op==TK_ALL ){
+    addrAeqB = addrAltB;
+  }else if( op==TK_INTERSECT ){
+    addrAeqB = addrAltB;
+    addrAltB++;
+  }else{
+    VdbeNoopComment((v, "A-eq-B subroutine"));
+    addrAeqB =
+    sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA); VdbeCoverage(v);
+    sqlite3VdbeGoto(v, labelCmpr);
+  }
+
+  /* Generate code to handle the case of A>B
+  */
+  VdbeNoopComment((v, "A-gt-B subroutine"));
+  addrAgtB = sqlite3VdbeCurrentAddr(v);
+  if( op==TK_ALL || op==TK_UNION ){
+    sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
+  }
+  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB); VdbeCoverage(v);
+  sqlite3VdbeGoto(v, labelCmpr);
+
+  /* This code runs once to initialize everything.
+  */
+  sqlite3VdbeJumpHere(v, addr1);
+  sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA_noB); VdbeCoverage(v);
+  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB); VdbeCoverage(v);
+
+  /* Implement the main merge loop
+  */
+  sqlite3VdbeResolveLabel(v, labelCmpr);
+  sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
+  sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy,
+                         (char*)pKeyMerge, P4_KEYINFO);
+  sqlite3VdbeChangeP5(v, OPFLAG_PERMUTE);
+  sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB); VdbeCoverage(v);
+
+  /* Jump to the this point in order to terminate the query.
+  */
+  sqlite3VdbeResolveLabel(v, labelEnd);
+
+  /* Make arrangements to free the 2nd and subsequent arms of the compound
+  ** after the parse has finished */
+  if( pSplit->pPrior ){
+    sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pSplit->pPrior);
+  }
+  pSplit->pPrior = pPrior;
+  pPrior->pNext = pSplit;
+  sqlite3ExprListDelete(db, pPrior->pOrderBy);
+  pPrior->pOrderBy = 0;
+
+  /*** TBD:  Insert subroutine calls to close cursors on incomplete
+  **** subqueries ****/
+  ExplainQueryPlanPop(pParse);
+  return pParse->nErr!=0;
+}
+#endif
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+
+/* An instance of the SubstContext object describes an substitution edit
+** to be performed on a parse tree.
+**
+** All references to columns in table iTable are to be replaced by corresponding
+** expressions in pEList.
+**
+** ## About "isOuterJoin":
+**
+** The isOuterJoin column indicates that the replacement will occur into a
+** position in the parent that NULL-able due to an OUTER JOIN.  Either the
+** target slot in the parent is the right operand of a LEFT JOIN, or one of
+** the left operands of a RIGHT JOIN.  In either case, we need to potentially
+** bypass the substituted expression with OP_IfNullRow.
+**
+** Suppose the original expression is an integer constant. Even though the table
+** has the nullRow flag set, because the expression is an integer constant,
+** it will not be NULLed out.  So instead, we insert an OP_IfNullRow opcode
+** that checks to see if the nullRow flag is set on the table.  If the nullRow
+** flag is set, then the value in the register is set to NULL and the original
+** expression is bypassed.  If the nullRow flag is not set, then the original
+** expression runs to populate the register.
+**
+** Example where this is needed:
+**
+**      CREATE TABLE t1(a INTEGER PRIMARY KEY, b INT);
+**      CREATE TABLE t2(x INT UNIQUE);
+**
+**      SELECT a,b,m,x FROM t1 LEFT JOIN (SELECT 59 AS m,x FROM t2) ON b=x;
+**
+** When the subquery on the right side of the LEFT JOIN is flattened, we
+** have to add OP_IfNullRow in front of the OP_Integer that implements the
+** "m" value of the subquery so that a NULL will be loaded instead of 59
+** when processing a non-matched row of the left.
+*/
+typedef struct SubstContext {
+  Parse *pParse;            /* The parsing context */
+  int iTable;               /* Replace references to this table */
+  int iNewTable;            /* New table number */
+  int isOuterJoin;          /* Add TK_IF_NULL_ROW opcodes on each replacement */
+  ExprList *pEList;         /* Replacement expressions */
+  ExprList *pCList;         /* Collation sequences for replacement expr */
+} SubstContext;
+
+/* Forward Declarations */
+static void substExprList(SubstContext*, ExprList*);
+static void substSelect(SubstContext*, Select*, int);
+
+/*
+** Scan through the expression pExpr.  Replace every reference to
+** a column in table number iTable with a copy of the iColumn-th
+** entry in pEList.  (But leave references to the ROWID column
+** unchanged.)
+**
+** This routine is part of the flattening procedure.  A subquery
+** whose result set is defined by pEList appears as entry in the
+** FROM clause of a SELECT such that the VDBE cursor assigned to that
+** FORM clause entry is iTable.  This routine makes the necessary
+** changes to pExpr so that it refers directly to the source table
+** of the subquery rather the result set of the subquery.
+*/
+static Expr *substExpr(
+  SubstContext *pSubst,  /* Description of the substitution */
+  Expr *pExpr            /* Expr in which substitution occurs */
+){
+  if( pExpr==0 ) return 0;
+  if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON)
+   && pExpr->w.iJoin==pSubst->iTable
+  ){
+    testcase( ExprHasProperty(pExpr, EP_InnerON) );
+    pExpr->w.iJoin = pSubst->iNewTable;
+  }
+  if( pExpr->op==TK_COLUMN
+   && pExpr->iTable==pSubst->iTable
+   && !ExprHasProperty(pExpr, EP_FixedCol)
+  ){
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+    if( pExpr->iColumn<0 ){
+      pExpr->op = TK_NULL;
+    }else
+#endif
+    {
+      Expr *pNew;
+      int iColumn;
+      Expr *pCopy;
+      Expr ifNullRow;
+      iColumn = pExpr->iColumn;
+      assert( iColumn>=0 );
+      assert( pSubst->pEList!=0 && iColumn<pSubst->pEList->nExpr );
+      assert( pExpr->pRight==0 );
+      pCopy = pSubst->pEList->a[iColumn].pExpr;
+      if( sqlite3ExprIsVector(pCopy) ){
+        sqlite3VectorErrorMsg(pSubst->pParse, pCopy);
+      }else{
+        sqlite3 *db = pSubst->pParse->db;
+        if( pSubst->isOuterJoin
+         && (pCopy->op!=TK_COLUMN || pCopy->iTable!=pSubst->iNewTable)
+        ){
+          memset(&ifNullRow, 0, sizeof(ifNullRow));
+          ifNullRow.op = TK_IF_NULL_ROW;
+          ifNullRow.pLeft = pCopy;
+          ifNullRow.iTable = pSubst->iNewTable;
+          ifNullRow.iColumn = -99;
+          ifNullRow.flags = EP_IfNullRow;
+          pCopy = &ifNullRow;
+        }
+        testcase( ExprHasProperty(pCopy, EP_Subquery) );
+        pNew = sqlite3ExprDup(db, pCopy, 0);
+        if( db->mallocFailed ){
+          sqlite3ExprDelete(db, pNew);
+          return pExpr;
+        }
+        if( pSubst->isOuterJoin ){
+          ExprSetProperty(pNew, EP_CanBeNull);
+        }
+        if( pNew->op==TK_TRUEFALSE ){
+          pNew->u.iValue = sqlite3ExprTruthValue(pNew);
+          pNew->op = TK_INTEGER;
+          ExprSetProperty(pNew, EP_IntValue);
+        }
+
+        /* Ensure that the expression now has an implicit collation sequence,
+        ** just as it did when it was a column of a view or sub-query. */
+        {
+          CollSeq *pNat = sqlite3ExprCollSeq(pSubst->pParse, pNew);
+          CollSeq *pColl = sqlite3ExprCollSeq(pSubst->pParse,
+                pSubst->pCList->a[iColumn].pExpr
+          );
+          if( pNat!=pColl || (pNew->op!=TK_COLUMN && pNew->op!=TK_COLLATE) ){
+            pNew = sqlite3ExprAddCollateString(pSubst->pParse, pNew,
+                (pColl ? pColl->zName : "BINARY")
+            );
+          }
+        }
+        ExprClearProperty(pNew, EP_Collate);
+        if( ExprHasProperty(pExpr,EP_OuterON|EP_InnerON) ){
+          sqlite3SetJoinExpr(pNew, pExpr->w.iJoin,
+                             pExpr->flags & (EP_OuterON|EP_InnerON));
+        }
+        sqlite3ExprDelete(db, pExpr);
+        pExpr = pNew;
+      }
+    }
+  }else{
+    if( pExpr->op==TK_IF_NULL_ROW && pExpr->iTable==pSubst->iTable ){
+      pExpr->iTable = pSubst->iNewTable;
+    }
+    pExpr->pLeft = substExpr(pSubst, pExpr->pLeft);
+    pExpr->pRight = substExpr(pSubst, pExpr->pRight);
+    if( ExprUseXSelect(pExpr) ){
+      substSelect(pSubst, pExpr->x.pSelect, 1);
+    }else{
+      substExprList(pSubst, pExpr->x.pList);
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( ExprHasProperty(pExpr, EP_WinFunc) ){
+      Window *pWin = pExpr->y.pWin;
+      pWin->pFilter = substExpr(pSubst, pWin->pFilter);
+      substExprList(pSubst, pWin->pPartition);
+      substExprList(pSubst, pWin->pOrderBy);
+    }
+#endif
+  }
+  return pExpr;
+}
+static void substExprList(
+  SubstContext *pSubst, /* Description of the substitution */
+  ExprList *pList       /* List to scan and in which to make substitutes */
+){
+  int i;
+  if( pList==0 ) return;
+  for(i=0; i<pList->nExpr; i++){
+    pList->a[i].pExpr = substExpr(pSubst, pList->a[i].pExpr);
+  }
+}
+static void substSelect(
+  SubstContext *pSubst, /* Description of the substitution */
+  Select *p,            /* SELECT statement in which to make substitutions */
+  int doPrior           /* Do substitutes on p->pPrior too */
+){
+  SrcList *pSrc;
+  SrcItem *pItem;
+  int i;
+  if( !p ) return;
+  do{
+    substExprList(pSubst, p->pEList);
+    substExprList(pSubst, p->pGroupBy);
+    substExprList(pSubst, p->pOrderBy);
+    p->pHaving = substExpr(pSubst, p->pHaving);
+    p->pWhere = substExpr(pSubst, p->pWhere);
+    pSrc = p->pSrc;
+    assert( pSrc!=0 );
+    for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
+      if( pItem->fg.isSubquery ){
+        substSelect(pSubst, pItem->u4.pSubq->pSelect, 1);
+      }
+      if( pItem->fg.isTabFunc ){
+        substExprList(pSubst, pItem->u1.pFuncArg);
+      }
+    }
+  }while( doPrior && (p = p->pPrior)!=0 );
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/*
+** pSelect is a SELECT statement and pSrcItem is one item in the FROM
+** clause of that SELECT.
+**
+** This routine scans the entire SELECT statement and recomputes the
+** pSrcItem->colUsed mask.
+*/
+static int recomputeColumnsUsedExpr(Walker *pWalker, Expr *pExpr){
+  SrcItem *pItem;
+  if( pExpr->op!=TK_COLUMN ) return WRC_Continue;
+  pItem = pWalker->u.pSrcItem;
+  if( pItem->iCursor!=pExpr->iTable ) return WRC_Continue;
+  if( pExpr->iColumn<0 ) return WRC_Continue;
+  pItem->colUsed |= sqlite3ExprColUsed(pExpr);
+  return WRC_Continue;
+}
+static void recomputeColumnsUsed(
+  Select *pSelect,                 /* The complete SELECT statement */
+  SrcItem *pSrcItem                /* Which FROM clause item to recompute */
+){
+  Walker w;
+  if( NEVER(pSrcItem->pSTab==0) ) return;
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = recomputeColumnsUsedExpr;
+  w.xSelectCallback = sqlite3SelectWalkNoop;
+  w.u.pSrcItem = pSrcItem;
+  pSrcItem->colUsed = 0;
+  sqlite3WalkSelect(&w, pSelect);
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/*
+** Assign new cursor numbers to each of the items in pSrc. For each
+** new cursor number assigned, set an entry in the aCsrMap[] array
+** to map the old cursor number to the new:
+**
+**     aCsrMap[iOld+1] = iNew;
+**
+** The array is guaranteed by the caller to be large enough for all
+** existing cursor numbers in pSrc.  aCsrMap[0] is the array size.
+**
+** If pSrc contains any sub-selects, call this routine recursively
+** on the FROM clause of each such sub-select, with iExcept set to -1.
+*/
+static void srclistRenumberCursors(
+  Parse *pParse,                  /* Parse context */
+  int *aCsrMap,                   /* Array to store cursor mappings in */
+  SrcList *pSrc,                  /* FROM clause to renumber */
+  int iExcept                     /* FROM clause item to skip */
+){
+  int i;
+  SrcItem *pItem;
+  for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){
+    if( i!=iExcept ){
+      Select *p;
+      assert( pItem->iCursor < aCsrMap[0] );
+      if( !pItem->fg.isRecursive || aCsrMap[pItem->iCursor+1]==0 ){
+        aCsrMap[pItem->iCursor+1] = pParse->nTab++;
+      }
+      pItem->iCursor = aCsrMap[pItem->iCursor+1];
+      if( pItem->fg.isSubquery ){
+        for(p=pItem->u4.pSubq->pSelect; p; p=p->pPrior){
+          srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1);
+        }
+      }
+    }
+  }
+}
+
+/*
+** *piCursor is a cursor number.  Change it if it needs to be mapped.
+*/
+static void renumberCursorDoMapping(Walker *pWalker, int *piCursor){
+  int *aCsrMap = pWalker->u.aiCol;
+  int iCsr = *piCursor;
+  if( iCsr < aCsrMap[0] && aCsrMap[iCsr+1]>0 ){
+    *piCursor = aCsrMap[iCsr+1];
+  }
+}
+
+/*
+** Expression walker callback used by renumberCursors() to update
+** Expr objects to match newly assigned cursor numbers.
+*/
+static int renumberCursorsCb(Walker *pWalker, Expr *pExpr){
+  int op = pExpr->op;
+  if( op==TK_COLUMN || op==TK_IF_NULL_ROW ){
+    renumberCursorDoMapping(pWalker, &pExpr->iTable);
+  }
+  if( ExprHasProperty(pExpr, EP_OuterON) ){
+    renumberCursorDoMapping(pWalker, &pExpr->w.iJoin);
+  }
+  return WRC_Continue;
+}
+
+/*
+** Assign a new cursor number to each cursor in the FROM clause (Select.pSrc)
+** of the SELECT statement passed as the second argument, and to each
+** cursor in the FROM clause of any FROM clause sub-selects, recursively.
+** Except, do not assign a new cursor number to the iExcept'th element in
+** the FROM clause of (*p). Update all expressions and other references
+** to refer to the new cursor numbers.
+**
+** Argument aCsrMap is an array that may be used for temporary working
+** space. Two guarantees are made by the caller:
+**
+**   * the array is larger than the largest cursor number used within the
+**     select statement passed as an argument, and
+**
+**   * the array entries for all cursor numbers that do *not* appear in
+**     FROM clauses of the select statement as described above are
+**     initialized to zero.
+*/
+static void renumberCursors(
+  Parse *pParse,                  /* Parse context */
+  Select *p,                      /* Select to renumber cursors within */
+  int iExcept,                    /* FROM clause item to skip */
+  int *aCsrMap                    /* Working space */
+){
+  Walker w;
+  srclistRenumberCursors(pParse, aCsrMap, p->pSrc, iExcept);
+  memset(&w, 0, sizeof(w));
+  w.u.aiCol = aCsrMap;
+  w.xExprCallback = renumberCursorsCb;
+  w.xSelectCallback = sqlite3SelectWalkNoop;
+  sqlite3WalkSelect(&w, p);
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+/*
+** If pSel is not part of a compound SELECT, return a pointer to its
+** expression list. Otherwise, return a pointer to the expression list
+** of the leftmost SELECT in the compound.
+*/
+static ExprList *findLeftmostExprlist(Select *pSel){
+  while( pSel->pPrior ){
+    pSel = pSel->pPrior;
+  }
+  return pSel->pEList;
+}
+
+/*
+** Return true if any of the result-set columns in the compound query
+** have incompatible affinities on one or more arms of the compound.
+*/
+static int compoundHasDifferentAffinities(Select *p){
+  int ii;
+  ExprList *pList;
+  assert( p!=0 );
+  assert( p->pEList!=0 );
+  assert( p->pPrior!=0 );
+  pList = p->pEList;
+  for(ii=0; ii<pList->nExpr; ii++){
+    char aff;
+    Select *pSub1;
+    assert( pList->a[ii].pExpr!=0 );
+    aff = sqlite3ExprAffinity(pList->a[ii].pExpr);
+    for(pSub1=p->pPrior; pSub1; pSub1=pSub1->pPrior){
+      assert( pSub1->pEList!=0 );
+      assert( pSub1->pEList->nExpr>ii );
+      assert( pSub1->pEList->a[ii].pExpr!=0 );
+      if( sqlite3ExprAffinity(pSub1->pEList->a[ii].pExpr)!=aff ){
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/*
+** This routine attempts to flatten subqueries as a performance optimization.
+** This routine returns 1 if it makes changes and 0 if no flattening occurs.
+**
+** To understand the concept of flattening, consider the following
+** query:
+**
+**     SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
+**
+** The default way of implementing this query is to execute the
+** subquery first and store the results in a temporary table, then
+** run the outer query on that temporary table.  This requires two
+** passes over the data.  Furthermore, because the temporary table
+** has no indices, the WHERE clause on the outer query cannot be
+** optimized.
+**
+** This routine attempts to rewrite queries such as the above into
+** a single flat select, like this:
+**
+**     SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
+**
+** The code generated for this simplification gives the same result
+** but only has to scan the data once.  And because indices might
+** exist on the table t1, a complete scan of the data might be
+** avoided.
+**
+** Flattening is subject to the following constraints:
+**
+**  (**)  We no longer attempt to flatten aggregate subqueries. Was:
+**        The subquery and the outer query cannot both be aggregates.
+**
+**  (**)  We no longer attempt to flatten aggregate subqueries. Was:
+**        (2) If the subquery is an aggregate then
+**        (2a) the outer query must not be a join and
+**        (2b) the outer query must not use subqueries
+**             other than the one FROM-clause subquery that is a candidate
+**             for flattening.  (This is due to ticket [2f7170d73bf9abf80]
+**             from 2015-02-09.)
+**
+**   (3)  If the subquery is the right operand of a LEFT JOIN then
+**        (3a) the subquery may not be a join and
+**        (3b) the FROM clause of the subquery may not contain a virtual
+**             table and
+**        (**) Was: "The outer query may not have a GROUP BY." This case
+**             is now managed correctly
+**        (3d) the outer query may not be DISTINCT.
+**        See also (26) for restrictions on RIGHT JOIN.
+**
+**   (4)  The subquery can not be DISTINCT.
+**
+**  (**)  At one point restrictions (4) and (5) defined a subset of DISTINCT
+**        sub-queries that were excluded from this optimization. Restriction
+**        (4) has since been expanded to exclude all DISTINCT subqueries.
+**
+**  (**)  We no longer attempt to flatten aggregate subqueries.  Was:
+**        If the subquery is aggregate, the outer query may not be DISTINCT.
+**
+**   (7)  The subquery must have a FROM clause.  TODO:  For subqueries without
+**        A FROM clause, consider adding a FROM clause with the special
+**        table sqlite_once that consists of a single row containing a
+**        single NULL.
+**
+**   (8)  If the subquery uses LIMIT then the outer query may not be a join.
+**
+**   (9)  If the subquery uses LIMIT then the outer query may not be aggregate.
+**
+**  (**)  Restriction (10) was removed from the code on 2005-02-05 but we
+**        accidentally carried the comment forward until 2014-09-15.  Original
+**        constraint: "If the subquery is aggregate then the outer query
+**        may not use LIMIT."
+**
+**  (11)  The subquery and the outer query may not both have ORDER BY clauses.
+**
+**  (**)  Not implemented.  Subsumed into restriction (3).  Was previously
+**        a separate restriction deriving from ticket #350.
+**
+**  (13)  The subquery and outer query may not both use LIMIT.
+**
+**  (14)  The subquery may not use OFFSET.
+**
+**  (15)  If the outer query is part of a compound select, then the
+**        subquery may not use LIMIT.
+**        (See ticket #2339 and ticket [02a8e81d44]).
+**
+**  (16)  If the outer query is aggregate, then the subquery may not
+**        use ORDER BY.  (Ticket #2942)  This used to not matter
+**        until we introduced the group_concat() function.
+**
+**  (17)  If the subquery is a compound select, then
+**        (17a) all compound operators must be a UNION ALL, and
+**        (17b) no terms within the subquery compound may be aggregate
+**              or DISTINCT, and
+**        (17c) every term within the subquery compound must have a FROM clause
+**        (17d) the outer query may not be
+**              (17d1) aggregate, or
+**              (17d2) DISTINCT
+**        (17e) the subquery may not contain window functions, and
+**        (17f) the subquery must not be the RHS of a LEFT JOIN.
+**        (17g) either the subquery is the first element of the outer
+**              query or there are no RIGHT or FULL JOINs in any arm
+**              of the subquery.  (This is a duplicate of condition (27b).)
+**        (17h) The corresponding result set expressions in all arms of the
+**              compound must have the same affinity.
+**
+**        The parent and sub-query may contain WHERE clauses. Subject to
+**        rules (11), (13) and (14), they may also contain ORDER BY,
+**        LIMIT and OFFSET clauses.  The subquery cannot use any compound
+**        operator other than UNION ALL because all the other compound
+**        operators have an implied DISTINCT which is disallowed by
+**        restriction (4).
+**
+**        Also, each component of the sub-query must return the same number
+**        of result columns. This is actually a requirement for any compound
+**        SELECT statement, but all the code here does is make sure that no
+**        such (illegal) sub-query is flattened. The caller will detect the
+**        syntax error and return a detailed message.
+**
+**  (18)  If the sub-query is a compound select, then all terms of the
+**        ORDER BY clause of the parent must be copies of a term returned
+**        by the parent query.
+**
+**  (19)  If the subquery uses LIMIT then the outer query may not
+**        have a WHERE clause.
+**
+**  (20)  If the sub-query is a compound select, then it must not use
+**        an ORDER BY clause.  Ticket #3773.  We could relax this constraint
+**        somewhat by saying that the terms of the ORDER BY clause must
+**        appear as unmodified result columns in the outer query.  But we
+**        have other optimizations in mind to deal with that case.
+**
+**  (21)  If the subquery uses LIMIT then the outer query may not be
+**        DISTINCT.  (See ticket [752e1646fc]).
+**
+**  (22)  The subquery may not be a recursive CTE.
+**
+**  (23)  If the outer query is a recursive CTE, then the sub-query may not be
+**        a compound query.  This restriction is because transforming the
+**        parent to a compound query confuses the code that handles
+**        recursive queries in multiSelect().
+**
+**  (**)  We no longer attempt to flatten aggregate subqueries.  Was:
+**        The subquery may not be an aggregate that uses the built-in min() or
+**        or max() functions.  (Without this restriction, a query like:
+**        "SELECT x FROM (SELECT max(y), x FROM t1)" would not necessarily
+**        return the value X for which Y was maximal.)
+**
+**  (25)  If either the subquery or the parent query contains a window
+**        function in the select list or ORDER BY clause, flattening
+**        is not attempted.
+**
+**  (26)  The subquery may not be the right operand of a RIGHT JOIN.
+**        See also (3) for restrictions on LEFT JOIN.
+**
+**  (27)  The subquery may not contain a FULL or RIGHT JOIN unless it
+**        is the first element of the parent query.  Two subcases:
+**        (27a) the subquery is not a compound query.
+**        (27b) the subquery is a compound query and the RIGHT JOIN occurs
+**              in any arm of the compound query.  (See also (17g).)
+**
+**  (28)  The subquery is not a MATERIALIZED CTE.  (This is handled
+**        in the caller before ever reaching this routine.)
+**
+**
+** In this routine, the "p" parameter is a pointer to the outer query.
+** The subquery is p->pSrc->a[iFrom].  isAgg is true if the outer query
+** uses aggregates.
+**
+** If flattening is not attempted, this routine is a no-op and returns 0.
+** If flattening is attempted this routine returns 1.
+**
+** All of the expression analysis must occur on both the outer query and
+** the subquery before this routine runs.
+*/
+static int flattenSubquery(
+  Parse *pParse,       /* Parsing context */
+  Select *p,           /* The parent or outer SELECT statement */
+  int iFrom,           /* Index in p->pSrc->a[] of the inner subquery */
+  int isAgg            /* True if outer SELECT uses aggregate functions */
+){
+  const char *zSavedAuthContext = pParse->zAuthContext;
+  Select *pParent;    /* Current UNION ALL term of the other query */
+  Select *pSub;       /* The inner query or "subquery" */
+  Select *pSub1;      /* Pointer to the rightmost select in sub-query */
+  SrcList *pSrc;      /* The FROM clause of the outer query */
+  SrcList *pSubSrc;   /* The FROM clause of the subquery */
+  int iParent;        /* VDBE cursor number of the pSub result set temp table */
+  int iNewParent = -1;/* Replacement table for iParent */
+  int isOuterJoin = 0; /* True if pSub is the right side of a LEFT JOIN */
+  int i;              /* Loop counter */
+  Expr *pWhere;                    /* The WHERE clause */
+  SrcItem *pSubitem;               /* The subquery */
+  sqlite3 *db = pParse->db;
+  Walker w;                        /* Walker to persist agginfo data */
+  int *aCsrMap = 0;
+
+  /* Check to see if flattening is permitted.  Return 0 if not.
+  */
+  assert( p!=0 );
+  assert( p->pPrior==0 );
+  if( OptimizationDisabled(db, SQLITE_QueryFlattener) ) return 0;
+  pSrc = p->pSrc;
+  assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
+  pSubitem = &pSrc->a[iFrom];
+  iParent = pSubitem->iCursor;
+  assert( pSubitem->fg.isSubquery );
+  pSub = pSubitem->u4.pSubq->pSelect;
+  assert( pSub!=0 );
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( p->pWin || pSub->pWin ) return 0;                  /* Restriction (25) */
+#endif
+
+  pSubSrc = pSub->pSrc;
+  assert( pSubSrc );
+  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
+  ** not arbitrary expressions, we allowed some combining of LIMIT and OFFSET
+  ** because they could be computed at compile-time.  But when LIMIT and OFFSET
+  ** became arbitrary expressions, we were forced to add restrictions (13)
+  ** and (14). */
+  if( pSub->pLimit && p->pLimit ) return 0;              /* Restriction (13) */
+  if( pSub->pLimit && pSub->pLimit->pRight ) return 0;   /* Restriction (14) */
+  if( (p->selFlags & SF_Compound)!=0 && pSub->pLimit ){
+    return 0;                                            /* Restriction (15) */
+  }
+  if( pSubSrc->nSrc==0 ) return 0;                       /* Restriction (7)  */
+  if( pSub->selFlags & SF_Distinct ) return 0;           /* Restriction (4)  */
+  if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){
+     return 0;         /* Restrictions (8)(9) */
+  }
+  if( p->pOrderBy && pSub->pOrderBy ){
+     return 0;                                           /* Restriction (11) */
+  }
+  if( isAgg && pSub->pOrderBy ) return 0;                /* Restriction (16) */
+  if( pSub->pLimit && p->pWhere ) return 0;              /* Restriction (19) */
+  if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
+     return 0;         /* Restriction (21) */
+  }
+  if( pSub->selFlags & (SF_Recursive) ){
+    return 0; /* Restrictions (22) */
+  }
+
+  /*
+  ** If the subquery is the right operand of a LEFT JOIN, then the
+  ** subquery may not be a join itself (3a). Example of why this is not
+  ** allowed:
+  **
+  **         t1 LEFT OUTER JOIN (t2 JOIN t3)
+  **
+  ** If we flatten the above, we would get
+  **
+  **         (t1 LEFT OUTER JOIN t2) JOIN t3
+  **
+  ** which is not at all the same thing.
+  **
+  ** See also tickets #306, #350, and #3300.
+  */
+  if( (pSubitem->fg.jointype & (JT_OUTER|JT_LTORJ))!=0 ){
+    if( pSubSrc->nSrc>1                        /* (3a) */
+     || IsVirtual(pSubSrc->a[0].pSTab)         /* (3b) */
+     || (p->selFlags & SF_Distinct)!=0         /* (3d) */
+     || (pSubitem->fg.jointype & JT_RIGHT)!=0  /* (26) */
+    ){
+      return 0;
+    }
+    isOuterJoin = 1;
+  }
+
+  assert( pSubSrc->nSrc>0 );  /* True by restriction (7) */
+  if( iFrom>0 && (pSubSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
+    return 0;   /* Restriction (27a) */
+  }
+
+  /* Condition (28) is blocked by the caller */
+  assert( !pSubitem->fg.isCte || pSubitem->u2.pCteUse->eM10d!=M10d_Yes );
+
+  /* Restriction (17): If the sub-query is a compound SELECT, then it must
+  ** use only the UNION ALL operator. And none of the simple select queries
+  ** that make up the compound SELECT are allowed to be aggregate or distinct
+  ** queries.
+  */
+  if( pSub->pPrior ){
+    int ii;
+    if( pSub->pOrderBy ){
+      return 0;  /* Restriction (20) */
+    }
+    if( isAgg || (p->selFlags & SF_Distinct)!=0 || isOuterJoin>0 ){
+      return 0; /* (17d1), (17d2), or (17f) */
+    }
+    for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
+      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
+      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
+      assert( pSub->pSrc!=0 );
+      assert( (pSub->selFlags & SF_Recursive)==0 );
+      assert( pSub->pEList->nExpr==pSub1->pEList->nExpr );
+      if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0    /* (17b) */
+       || (pSub1->pPrior && pSub1->op!=TK_ALL)                 /* (17a) */
+       || pSub1->pSrc->nSrc<1                                  /* (17c) */
+#ifndef SQLITE_OMIT_WINDOWFUNC
+       || pSub1->pWin                                          /* (17e) */
+#endif
+      ){
+        return 0;
+      }
+      if( iFrom>0 && (pSub1->pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
+        /* Without this restriction, the JT_LTORJ flag would end up being
+        ** omitted on left-hand tables of the right join that is being
+        ** flattened. */
+        return 0;   /* Restrictions (17g), (27b) */
+      }
+      testcase( pSub1->pSrc->nSrc>1 );
+    }
+
+    /* Restriction (18). */
+    if( p->pOrderBy ){
+      for(ii=0; ii<p->pOrderBy->nExpr; ii++){
+        if( p->pOrderBy->a[ii].u.x.iOrderByCol==0 ) return 0;
+      }
+    }
+
+    /* Restriction (23) */
+    if( (p->selFlags & SF_Recursive) ) return 0;
+
+    /* Restriction (17h) */
+    if( compoundHasDifferentAffinities(pSub) ) return 0;
+
+    if( pSrc->nSrc>1 ){
+      if( pParse->nSelect>500 ) return 0;
+      if( OptimizationDisabled(db, SQLITE_FlttnUnionAll) ) return 0;
+      aCsrMap = sqlite3DbMallocZero(db, ((i64)pParse->nTab+1)*sizeof(int));
+      if( aCsrMap ) aCsrMap[0] = pParse->nTab;
+    }
+  }
+
+  /***** If we reach this point, flattening is permitted. *****/
+  TREETRACE(0x4,pParse,p,("flatten %u.%p from term %d\n",
+                   pSub->selId, pSub, iFrom));
+
+  /* Authorize the subquery */
+  pParse->zAuthContext = pSubitem->zName;
+  TESTONLY(i =) sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0);
+  testcase( i==SQLITE_DENY );
+  pParse->zAuthContext = zSavedAuthContext;
+
+  /* Delete the transient structures associated with the subquery */
+
+  if( ALWAYS(pSubitem->fg.isSubquery) ){
+    pSub1 = sqlite3SubqueryDetach(db, pSubitem);
+  }else{
+    pSub1 = 0;
+  }
+  assert( pSubitem->fg.isSubquery==0 );
+  assert( pSubitem->fg.fixedSchema==0 );
+  sqlite3DbFree(db, pSubitem->zName);
+  sqlite3DbFree(db, pSubitem->zAlias);
+  pSubitem->zName = 0;
+  pSubitem->zAlias = 0;
+  assert( pSubitem->fg.isUsing!=0 || pSubitem->u3.pOn==0 );
+
+  /* If the sub-query is a compound SELECT statement, then (by restrictions
+  ** 17 and 18 above) it must be a UNION ALL and the parent query must
+  ** be of the form:
+  **
+  **     SELECT <expr-list> FROM (<sub-query>) <where-clause>
+  **
+  ** followed by any ORDER BY, LIMIT and/or OFFSET clauses. This block
+  ** creates N-1 copies of the parent query without any ORDER BY, LIMIT or
+  ** OFFSET clauses and joins them to the left-hand-side of the original
+  ** using UNION ALL operators. In this case N is the number of simple
+  ** select statements in the compound sub-query.
+  **
+  ** Example:
+  **
+  **     SELECT a+1 FROM (
+  **        SELECT x FROM tab
+  **        UNION ALL
+  **        SELECT y FROM tab
+  **        UNION ALL
+  **        SELECT abs(z*2) FROM tab2
+  **     ) WHERE a!=5 ORDER BY 1
+  **
+  ** Transformed into:
+  **
+  **     SELECT x+1 FROM tab WHERE x+1!=5
+  **     UNION ALL
+  **     SELECT y+1 FROM tab WHERE y+1!=5
+  **     UNION ALL
+  **     SELECT abs(z*2)+1 FROM tab2 WHERE abs(z*2)+1!=5
+  **     ORDER BY 1
+  **
+  ** We call this the "compound-subquery flattening".
+  */
+  for(pSub=pSub->pPrior; pSub; pSub=pSub->pPrior){
+    Select *pNew;
+    ExprList *pOrderBy = p->pOrderBy;
+    Expr *pLimit = p->pLimit;
+    Select *pPrior = p->pPrior;
+    Table *pItemTab = pSubitem->pSTab;
+    pSubitem->pSTab = 0;
+    p->pOrderBy = 0;
+    p->pPrior = 0;
+    p->pLimit = 0;
+    pNew = sqlite3SelectDup(db, p, 0);
+    p->pLimit = pLimit;
+    p->pOrderBy = pOrderBy;
+    p->op = TK_ALL;
+    pSubitem->pSTab = pItemTab;
+    if( pNew==0 ){
+      p->pPrior = pPrior;
+    }else{
+      pNew->selId = ++pParse->nSelect;
+      if( aCsrMap && ALWAYS(db->mallocFailed==0) ){
+        renumberCursors(pParse, pNew, iFrom, aCsrMap);
+      }
+      pNew->pPrior = pPrior;
+      if( pPrior ) pPrior->pNext = pNew;
+      pNew->pNext = p;
+      p->pPrior = pNew;
+      TREETRACE(0x4,pParse,p,("compound-subquery flattener"
+                              " creates %u as peer\n",pNew->selId));
+    }
+    assert( pSubitem->fg.isSubquery==0 );
+  }
+  sqlite3DbFree(db, aCsrMap);
+  if( db->mallocFailed ){
+    assert( pSubitem->fg.fixedSchema==0 );
+    assert( pSubitem->fg.isSubquery==0 );
+    assert( pSubitem->u4.zDatabase==0 );
+    sqlite3SrcItemAttachSubquery(pParse, pSubitem, pSub1, 0);
+    return 1;
+  }
+
+  /* Defer deleting the Table object associated with the
+  ** subquery until code generation is
+  ** complete, since there may still exist Expr.pTab entries that
+  ** refer to the subquery even after flattening.  Ticket #3346.
+  **
+  ** pSubitem->pTab is always non-NULL by test restrictions and tests above.
+  */
+  if( ALWAYS(pSubitem->pSTab!=0) ){
+    Table *pTabToDel = pSubitem->pSTab;
+    if( pTabToDel->nTabRef==1 ){
+      Parse *pToplevel = sqlite3ParseToplevel(pParse);
+      sqlite3ParserAddCleanup(pToplevel, sqlite3DeleteTableGeneric, pTabToDel);
+      testcase( pToplevel->earlyCleanup );
+    }else{
+      pTabToDel->nTabRef--;
+    }
+    pSubitem->pSTab = 0;
+  }
+
+  /* The following loop runs once for each term in a compound-subquery
+  ** flattening (as described above).  If we are doing a different kind
+  ** of flattening - a flattening other than a compound-subquery flattening -
+  ** then this loop only runs once.
+  **
+  ** This loop moves all of the FROM elements of the subquery into the
+  ** the FROM clause of the outer query.  Before doing this, remember
+  ** the cursor number for the original outer query FROM element in
+  ** iParent.  The iParent cursor will never be used.  Subsequent code
+  ** will scan expressions looking for iParent references and replace
+  ** those references with expressions that resolve to the subquery FROM
+  ** elements we are now copying in.
+  */
+  pSub = pSub1;
+  for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){
+    int nSubSrc;
+    u8 jointype = 0;
+    u8 ltorj = pSrc->a[iFrom].fg.jointype & JT_LTORJ;
+    assert( pSub!=0 );
+    pSubSrc = pSub->pSrc;     /* FROM clause of subquery */
+    nSubSrc = pSubSrc->nSrc;  /* Number of terms in subquery FROM clause */
+    pSrc = pParent->pSrc;     /* FROM clause of the outer query */
+
+    if( pParent==p ){
+      jointype = pSubitem->fg.jointype;     /* First time through the loop */
+    }
+
+    /* The subquery uses a single slot of the FROM clause of the outer
+    ** query.  If the subquery has more than one element in its FROM clause,
+    ** then expand the outer query to make space for it to hold all elements
+    ** of the subquery.
+    **
+    ** Example:
+    **
+    **    SELECT * FROM tabA, (SELECT * FROM sub1, sub2), tabB;
+    **
+    ** The outer query has 3 slots in its FROM clause.  One slot of the
+    ** outer query (the middle slot) is used by the subquery.  The next
+    ** block of code will expand the outer query FROM clause to 4 slots.
+    ** The middle slot is expanded to two slots in order to make space
+    ** for the two elements in the FROM clause of the subquery.
+    */
+    if( nSubSrc>1 ){
+      pSrc = sqlite3SrcListEnlarge(pParse, pSrc, nSubSrc-1,iFrom+1);
+      if( pSrc==0 ) break;
+      pParent->pSrc = pSrc;
+    }
+
+    /* Transfer the FROM clause terms from the subquery into the
+    ** outer query.
+    */
+    iNewParent = pSubSrc->a[0].iCursor;
+    for(i=0; i<nSubSrc; i++){
+      SrcItem *pItem = &pSrc->a[i+iFrom];
+      assert( pItem->fg.isTabFunc==0 );
+      assert( pItem->fg.isSubquery
+           || pItem->fg.fixedSchema
+           || pItem->u4.zDatabase==0 );
+      if( pItem->fg.isUsing ) sqlite3IdListDelete(db, pItem->u3.pUsing);
+      *pItem = pSubSrc->a[i];
+      pItem->fg.jointype |= ltorj;
+      memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
+    }
+    pSrc->a[iFrom].fg.jointype &= JT_LTORJ;
+    pSrc->a[iFrom].fg.jointype |= jointype | ltorj;
+
+    /* Now begin substituting subquery result set expressions for
+    ** references to the iParent in the outer query.
+    **
+    ** Example:
+    **
+    **   SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
+    **   \                     \_____________ subquery __________/          /
+    **    \_____________________ outer query ______________________________/
+    **
+    ** We look at every expression in the outer query and every place we see
+    ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
+    */
+    if( pSub->pOrderBy && (pParent->selFlags & SF_NoopOrderBy)==0 ){
+      /* At this point, any non-zero iOrderByCol values indicate that the
+      ** ORDER BY column expression is identical to the iOrderByCol'th
+      ** expression returned by SELECT statement pSub. Since these values
+      ** do not necessarily correspond to columns in SELECT statement pParent,
+      ** zero them before transferring the ORDER BY clause.
+      **
+      ** Not doing this may cause an error if a subsequent call to this
+      ** function attempts to flatten a compound sub-query into pParent
+      ** (the only way this can happen is if the compound sub-query is
+      ** currently part of pSub->pSrc). See ticket [d11a6e908f].  */
+      ExprList *pOrderBy = pSub->pOrderBy;
+      for(i=0; i<pOrderBy->nExpr; i++){
+        pOrderBy->a[i].u.x.iOrderByCol = 0;
+      }
+      assert( pParent->pOrderBy==0 );
+      pParent->pOrderBy = pOrderBy;
+      pSub->pOrderBy = 0;
+    }
+    pWhere = pSub->pWhere;
+    pSub->pWhere = 0;
+    if( isOuterJoin>0 ){
+      assert( pSubSrc->nSrc==1 );
+      sqlite3SetJoinExpr(pWhere, iNewParent, EP_OuterON);
+    }
+    if( pWhere ){
+      if( pParent->pWhere ){
+        pParent->pWhere = sqlite3PExpr(pParse, TK_AND, pWhere, pParent->pWhere);
+      }else{
+        pParent->pWhere = pWhere;
+      }
+    }
+    if( db->mallocFailed==0 ){
+      SubstContext x;
+      x.pParse = pParse;
+      x.iTable = iParent;
+      x.iNewTable = iNewParent;
+      x.isOuterJoin = isOuterJoin;
+      x.pEList = pSub->pEList;
+      x.pCList = findLeftmostExprlist(pSub);
+      substSelect(&x, pParent, 0);
+    }
+
+    /* The flattened query is a compound if either the inner or the
+    ** outer query is a compound. */
+    pParent->selFlags |= pSub->selFlags & SF_Compound;
+    assert( (pSub->selFlags & SF_Distinct)==0 ); /* restriction (17b) */
+
+    /*
+    ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
+    **
+    ** One is tempted to try to add a and b to combine the limits.  But this
+    ** does not work if either limit is negative.
+    */
+    if( pSub->pLimit ){
+      pParent->pLimit = pSub->pLimit;
+      pSub->pLimit = 0;
+    }
+
+    /* Recompute the SrcItem.colUsed masks for the flattened
+    ** tables. */
+    for(i=0; i<nSubSrc; i++){
+      recomputeColumnsUsed(pParent, &pSrc->a[i+iFrom]);
+    }
+  }
+
+  /* Finally, delete what is left of the subquery and return success.
+  */
+  sqlite3AggInfoPersistWalkerInit(&w, pParse);
+  sqlite3WalkSelect(&w,pSub1);
+  sqlite3SelectDelete(db, pSub1);
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x4 ){
+    TREETRACE(0x4,pParse,p,("After flattening:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+
+  return 1;
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+/*
+** A structure to keep track of all of the column values that are fixed to
+** a known value due to WHERE clause constraints of the form COLUMN=VALUE.
+*/
+typedef struct WhereConst WhereConst;
+struct WhereConst {
+  Parse *pParse;   /* Parsing context */
+  u8 *pOomFault;   /* Pointer to pParse->db->mallocFailed */
+  int nConst;      /* Number for COLUMN=CONSTANT terms */
+  int nChng;       /* Number of times a constant is propagated */
+  int bHasAffBlob; /* At least one column in apExpr[] as affinity BLOB */
+  u32 mExcludeOn;  /* Which ON expressions to exclude from considertion.
+                   ** Either EP_OuterON or EP_InnerON|EP_OuterON */
+  Expr **apExpr;   /* [i*2] is COLUMN and [i*2+1] is VALUE */
+};
+
+/*
+** Add a new entry to the pConst object.  Except, do not add duplicate
+** pColumn entries.  Also, do not add if doing so would not be appropriate.
+**
+** The caller guarantees the pColumn is a column and pValue is a constant.
+** This routine has to do some additional checks before completing the
+** insert.
+*/
+static void constInsert(
+  WhereConst *pConst,  /* The WhereConst into which we are inserting */
+  Expr *pColumn,       /* The COLUMN part of the constraint */
+  Expr *pValue,        /* The VALUE part of the constraint */
+  Expr *pExpr          /* Overall expression: COLUMN=VALUE or VALUE=COLUMN */
+){
+  int i;
+  assert( pColumn->op==TK_COLUMN );
+  assert( sqlite3ExprIsConstant(pConst->pParse, pValue) );
+
+  if( ExprHasProperty(pColumn, EP_FixedCol) ) return;
+  if( sqlite3ExprAffinity(pValue)!=0 ) return;
+  if( !sqlite3IsBinary(sqlite3ExprCompareCollSeq(pConst->pParse,pExpr)) ){
+    return;
+  }
+
+  /* 2018-10-25 ticket [cf5ed20f]
+  ** Make sure the same pColumn is not inserted more than once */
+  for(i=0; i<pConst->nConst; i++){
+    const Expr *pE2 = pConst->apExpr[i*2];
+    assert( pE2->op==TK_COLUMN );
+    if( pE2->iTable==pColumn->iTable
+     && pE2->iColumn==pColumn->iColumn
+    ){
+      return;  /* Already present.  Return without doing anything. */
+    }
+  }
+  if( sqlite3ExprAffinity(pColumn)==SQLITE_AFF_BLOB ){
+    pConst->bHasAffBlob = 1;
+  }
+
+  pConst->nConst++;
+  pConst->apExpr = sqlite3DbReallocOrFree(pConst->pParse->db, pConst->apExpr,
+                         pConst->nConst*2*sizeof(Expr*));
+  if( pConst->apExpr==0 ){
+    pConst->nConst = 0;
+  }else{
+    pConst->apExpr[pConst->nConst*2-2] = pColumn;
+    pConst->apExpr[pConst->nConst*2-1] = pValue;
+  }
+}
+
+/*
+** Find all terms of COLUMN=VALUE or VALUE=COLUMN in pExpr where VALUE
+** is a constant expression and where the term must be true because it
+** is part of the AND-connected terms of the expression.  For each term
+** found, add it to the pConst structure.
+*/
+static void findConstInWhere(WhereConst *pConst, Expr *pExpr){
+  Expr *pRight, *pLeft;
+  if( NEVER(pExpr==0) ) return;
+  if( ExprHasProperty(pExpr, pConst->mExcludeOn) ){
+    testcase( ExprHasProperty(pExpr, EP_OuterON) );
+    testcase( ExprHasProperty(pExpr, EP_InnerON) );
+    return;
+  }
+  if( pExpr->op==TK_AND ){
+    findConstInWhere(pConst, pExpr->pRight);
+    findConstInWhere(pConst, pExpr->pLeft);
+    return;
+  }
+  if( pExpr->op!=TK_EQ ) return;
+  pRight = pExpr->pRight;
+  pLeft = pExpr->pLeft;
+  assert( pRight!=0 );
+  assert( pLeft!=0 );
+  if( pRight->op==TK_COLUMN && sqlite3ExprIsConstant(pConst->pParse, pLeft) ){
+    constInsert(pConst,pRight,pLeft,pExpr);
+  }
+  if( pLeft->op==TK_COLUMN && sqlite3ExprIsConstant(pConst->pParse, pRight) ){
+    constInsert(pConst,pLeft,pRight,pExpr);
+  }
+}
+
+/*
+** This is a helper function for Walker callback propagateConstantExprRewrite().
+**
+** Argument pExpr is a candidate expression to be replaced by a value. If
+** pExpr is equivalent to one of the columns named in pWalker->u.pConst,
+** then overwrite it with the corresponding value. Except, do not do so
+** if argument bIgnoreAffBlob is non-zero and the affinity of pExpr
+** is SQLITE_AFF_BLOB.
+*/
+static int propagateConstantExprRewriteOne(
+  WhereConst *pConst,
+  Expr *pExpr,
+  int bIgnoreAffBlob
+){
+  int i;
+  if( pConst->pOomFault[0] ) return WRC_Prune;
+  if( pExpr->op!=TK_COLUMN ) return WRC_Continue;
+  if( ExprHasProperty(pExpr, EP_FixedCol|pConst->mExcludeOn) ){
+    testcase( ExprHasProperty(pExpr, EP_FixedCol) );
+    testcase( ExprHasProperty(pExpr, EP_OuterON) );
+    testcase( ExprHasProperty(pExpr, EP_InnerON) );
+    return WRC_Continue;
+  }
+  for(i=0; i<pConst->nConst; i++){
+    Expr *pColumn = pConst->apExpr[i*2];
+    if( pColumn==pExpr ) continue;
+    if( pColumn->iTable!=pExpr->iTable ) continue;
+    if( pColumn->iColumn!=pExpr->iColumn ) continue;
+    if( bIgnoreAffBlob && sqlite3ExprAffinity(pColumn)==SQLITE_AFF_BLOB ){
+      break;
+    }
+    /* A match is found.  Add the EP_FixedCol property */
+    pConst->nChng++;
+    ExprClearProperty(pExpr, EP_Leaf);
+    ExprSetProperty(pExpr, EP_FixedCol);
+    assert( pExpr->pLeft==0 );
+    pExpr->pLeft = sqlite3ExprDup(pConst->pParse->db, pConst->apExpr[i*2+1], 0);
+    if( pConst->pParse->db->mallocFailed ) return WRC_Prune;
+    break;
+  }
+  return WRC_Prune;
+}
+
+/*
+** This is a Walker expression callback. pExpr is a node from the WHERE
+** clause of a SELECT statement. This function examines pExpr to see if
+** any substitutions based on the contents of pWalker->u.pConst should
+** be made to pExpr or its immediate children.
+**
+** A substitution is made if:
+**
+**   + pExpr is a column with an affinity other than BLOB that matches
+**     one of the columns in pWalker->u.pConst, or
+**
+**   + pExpr is a binary comparison operator (=, <=, >=, <, >) that
+**     uses an affinity other than TEXT and one of its immediate
+**     children is a column that matches one of the columns in
+**     pWalker->u.pConst.
+*/
+static int propagateConstantExprRewrite(Walker *pWalker, Expr *pExpr){
+  WhereConst *pConst = pWalker->u.pConst;
+  assert( TK_GT==TK_EQ+1 );
+  assert( TK_LE==TK_EQ+2 );
+  assert( TK_LT==TK_EQ+3 );
+  assert( TK_GE==TK_EQ+4 );
+  if( pConst->bHasAffBlob ){
+    if( (pExpr->op>=TK_EQ && pExpr->op<=TK_GE)
+     || pExpr->op==TK_IS
+    ){
+      propagateConstantExprRewriteOne(pConst, pExpr->pLeft, 0);
+      if( pConst->pOomFault[0] ) return WRC_Prune;
+      if( sqlite3ExprAffinity(pExpr->pLeft)!=SQLITE_AFF_TEXT ){
+        propagateConstantExprRewriteOne(pConst, pExpr->pRight, 0);
+      }
+    }
+  }
+  return propagateConstantExprRewriteOne(pConst, pExpr, pConst->bHasAffBlob);
+}
+
+/*
+** The WHERE-clause constant propagation optimization.
+**
+** If the WHERE clause contains terms of the form COLUMN=CONSTANT or
+** CONSTANT=COLUMN that are top-level AND-connected terms that are not
+** part of a ON clause from a LEFT JOIN, then throughout the query
+** replace all other occurrences of COLUMN with CONSTANT.
+**
+** For example, the query:
+**
+**      SELECT * FROM t1, t2, t3 WHERE t1.a=39 AND t2.b=t1.a AND t3.c=t2.b
+**
+** Is transformed into
+**
+**      SELECT * FROM t1, t2, t3 WHERE t1.a=39 AND t2.b=39 AND t3.c=39
+**
+** Return true if any transformations where made and false if not.
+**
+** Implementation note:  Constant propagation is tricky due to affinity
+** and collating sequence interactions.  Consider this example:
+**
+**    CREATE TABLE t1(a INT,b TEXT);
+**    INSERT INTO t1 VALUES(123,'0123');
+**    SELECT * FROM t1 WHERE a=123 AND b=a;
+**    SELECT * FROM t1 WHERE a=123 AND b=123;
+**
+** The two SELECT statements above should return different answers.  b=a
+** is always true because the comparison uses numeric affinity, but b=123
+** is false because it uses text affinity and '0123' is not the same as '123'.
+** To work around this, the expression tree is not actually changed from
+** "b=a" to "b=123" but rather the "a" in "b=a" is tagged with EP_FixedCol
+** and the "123" value is hung off of the pLeft pointer.  Code generator
+** routines know to generate the constant "123" instead of looking up the
+** column value.  Also, to avoid collation problems, this optimization is
+** only attempted if the "a=123" term uses the default BINARY collation.
+**
+** 2021-05-25 forum post 6a06202608: Another troublesome case is...
+**
+**    CREATE TABLE t1(x);
+**    INSERT INTO t1 VALUES(10.0);
+**    SELECT 1 FROM t1 WHERE x=10 AND x LIKE 10;
+**
+** The query should return no rows, because the t1.x value is '10.0' not '10'
+** and '10.0' is not LIKE '10'.  But if we are not careful, the first WHERE
+** term "x=10" will cause the second WHERE term to become "10 LIKE 10",
+** resulting in a false positive.  To avoid this, constant propagation for
+** columns with BLOB affinity is only allowed if the constant is used with
+** operators ==, <=, <, >=, >, or IS in a way that will cause the correct
+** type conversions to occur.  See logic associated with the bHasAffBlob flag
+** for details.
+*/
+static int propagateConstants(
+  Parse *pParse,   /* The parsing context */
+  Select *p        /* The query in which to propagate constants */
+){
+  WhereConst x;
+  Walker w;
+  int nChng = 0;
+  x.pParse = pParse;
+  x.pOomFault = &pParse->db->mallocFailed;
+  do{
+    x.nConst = 0;
+    x.nChng = 0;
+    x.apExpr = 0;
+    x.bHasAffBlob = 0;
+    if( ALWAYS(p->pSrc!=0)
+     && p->pSrc->nSrc>0
+     && (p->pSrc->a[0].fg.jointype & JT_LTORJ)!=0
+    ){
+      /* Do not propagate constants on any ON clause if there is a
+      ** RIGHT JOIN anywhere in the query */
+      x.mExcludeOn = EP_InnerON | EP_OuterON;
+    }else{
+      /* Do not propagate constants through the ON clause of a LEFT JOIN */
+      x.mExcludeOn = EP_OuterON;
+    }
+    findConstInWhere(&x, p->pWhere);
+    if( x.nConst ){
+      memset(&w, 0, sizeof(w));
+      w.pParse = pParse;
+      w.xExprCallback = propagateConstantExprRewrite;
+      w.xSelectCallback = sqlite3SelectWalkNoop;
+      w.xSelectCallback2 = 0;
+      w.walkerDepth = 0;
+      w.u.pConst = &x;
+      sqlite3WalkExpr(&w, p->pWhere);
+      sqlite3DbFree(x.pParse->db, x.apExpr);
+      nChng += x.nChng;
+    }
+  }while( x.nChng );
+  return nChng;
+}
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+# if !defined(SQLITE_OMIT_WINDOWFUNC)
+/*
+** This function is called to determine whether or not it is safe to
+** push WHERE clause expression pExpr down to FROM clause sub-query
+** pSubq, which contains at least one window function. Return 1
+** if it is safe and the expression should be pushed down, or 0
+** otherwise.
+**
+** It is only safe to push the expression down if it consists only
+** of constants and copies of expressions that appear in the PARTITION
+** BY clause of all window function used by the sub-query. It is safe
+** to filter out entire partitions, but not rows within partitions, as
+** this may change the results of the window functions.
+**
+** At the time this function is called it is guaranteed that
+**
+**   * the sub-query uses only one distinct window frame, and
+**   * that the window frame has a PARTITION BY clause.
+*/
+static int pushDownWindowCheck(Parse *pParse, Select *pSubq, Expr *pExpr){
+  assert( pSubq->pWin->pPartition );
+  assert( (pSubq->selFlags & SF_MultiPart)==0 );
+  assert( pSubq->pPrior==0 );
+  return sqlite3ExprIsConstantOrGroupBy(pParse, pExpr, pSubq->pWin->pPartition);
+}
+# endif /* SQLITE_OMIT_WINDOWFUNC */
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+/*
+** Make copies of relevant WHERE clause terms of the outer query into
+** the WHERE clause of subquery.  Example:
+**
+**    SELECT * FROM (SELECT a AS x, c-d AS y FROM t1) WHERE x=5 AND y=10;
+**
+** Transformed into:
+**
+**    SELECT * FROM (SELECT a AS x, c-d AS y FROM t1 WHERE a=5 AND c-d=10)
+**     WHERE x=5 AND y=10;
+**
+** The hope is that the terms added to the inner query will make it more
+** efficient.
+**
+** NAME AMBIGUITY
+**
+** This optimization is called the "WHERE-clause push-down optimization"
+** or sometimes the "predicate push-down optimization".
+**
+** Do not confuse this optimization with another unrelated optimization
+** with a similar name:  The "MySQL push-down optimization" causes WHERE
+** clause terms that can be evaluated using only the index and without
+** reference to the table are run first, so that if they are false,
+** unnecessary table seeks are avoided.
+**
+** RULES
+**
+** Do not attempt this optimization if:
+**
+**   (1) (** This restriction was removed on 2017-09-29.  We used to
+**           disallow this optimization for aggregate subqueries, but now
+**           it is allowed by putting the extra terms on the HAVING clause.
+**           The added HAVING clause is pointless if the subquery lacks
+**           a GROUP BY clause.  But such a HAVING clause is also harmless
+**           so there does not appear to be any reason to add extra logic
+**           to suppress it. **)
+**
+**   (2) The inner query is the recursive part of a common table expression.
+**
+**   (3) The inner query has a LIMIT clause (since the changes to the WHERE
+**       clause would change the meaning of the LIMIT).
+**
+**   (4) The inner query is the right operand of a LEFT JOIN and the
+**       expression to be pushed down does not come from the ON clause
+**       on that LEFT JOIN.
+**
+**   (5) The WHERE clause expression originates in the ON or USING clause
+**       of a LEFT JOIN where iCursor is not the right-hand table of that
+**       left join.  An example:
+**
+**           SELECT *
+**           FROM (SELECT 1 AS a1 UNION ALL SELECT 2) AS aa
+**           JOIN (SELECT 1 AS b2 UNION ALL SELECT 2) AS bb ON (a1=b2)
+**           LEFT JOIN (SELECT 8 AS c3 UNION ALL SELECT 9) AS cc ON (b2=2);
+**
+**       The correct answer is three rows:  (1,1,NULL),(2,2,8),(2,2,9).
+**       But if the (b2=2) term were to be pushed down into the bb subquery,
+**       then the (1,1,NULL) row would be suppressed.
+**
+**   (6) Window functions make things tricky as changes to the WHERE clause
+**       of the inner query could change the window over which window
+**       functions are calculated. Therefore, do not attempt the optimization
+**       if:
+**
+**     (6a) The inner query uses multiple incompatible window partitions.
+**
+**     (6b) The inner query is a compound and uses window-functions.
+**
+**     (6c) The WHERE clause does not consist entirely of constants and
+**          copies of expressions found in the PARTITION BY clause of
+**          all window-functions used by the sub-query. It is safe to
+**          filter out entire partitions, as this does not change the
+**          window over which any window-function is calculated.
+**
+**   (7) The inner query is a Common Table Expression (CTE) that should
+**       be materialized.  (This restriction is implemented in the calling
+**       routine.)
+**
+**   (8) If the subquery is a compound that uses UNION, INTERSECT,
+**       or EXCEPT, then all of the result set columns for all arms of
+**       the compound must use the BINARY collating sequence.
+**
+**   (9) All three of the following are true:
+**
+**       (9a) The WHERE clause expression originates in the ON or USING clause
+**            of a join (either an INNER or an OUTER join), and
+**
+**       (9b) The subquery is to the right of the ON/USING clause
+**
+**       (9c) There is a RIGHT JOIN (or FULL JOIN) in between the ON/USING
+**            clause and the subquery.
+**
+**       Without this restriction, the WHERE-clause push-down optimization
+**       might move the ON/USING filter expression from the left side of a
+**       RIGHT JOIN over to the right side, which leads to incorrect answers.
+**       See also restriction (6) in sqlite3ExprIsSingleTableConstraint().
+**
+**  (10) The inner query is not the right-hand table of a RIGHT JOIN.
+**
+**  (11) The subquery is not a VALUES clause
+**
+**  (12) The WHERE clause is not "rowid ISNULL" or the equivalent.  This
+**       case only comes up if SQLite is compiled using
+**       SQLITE_ALLOW_ROWID_IN_VIEW.
+**
+** Return 0 if no changes are made and non-zero if one or more WHERE clause
+** terms are duplicated into the subquery.
+*/
+static int pushDownWhereTerms(
+  Parse *pParse,        /* Parse context (for malloc() and error reporting) */
+  Select *pSubq,        /* The subquery whose WHERE clause is to be augmented */
+  Expr *pWhere,         /* The WHERE clause of the outer query */
+  SrcList *pSrcList,    /* The complete from clause of the outer query */
+  int iSrc              /* Which FROM clause term to try to push into  */
+){
+  Expr *pNew;
+  SrcItem *pSrc;        /* The subquery FROM term into which WHERE is pushed */
+  int nChng = 0;
+  pSrc = &pSrcList->a[iSrc];
+  if( pWhere==0 ) return 0;
+  if( pSubq->selFlags & (SF_Recursive|SF_MultiPart) ){
+    return 0;           /* restrictions (2) and (11) */
+  }
+  if( pSrc->fg.jointype & (JT_LTORJ|JT_RIGHT) ){
+    return 0;           /* restrictions (10) */
+  }
+
+  if( pSubq->pPrior ){
+    Select *pSel;
+    int notUnionAll = 0;
+    for(pSel=pSubq; pSel; pSel=pSel->pPrior){
+      u8 op = pSel->op;
+      assert( op==TK_ALL || op==TK_SELECT
+           || op==TK_UNION || op==TK_INTERSECT || op==TK_EXCEPT );
+      if( op!=TK_ALL && op!=TK_SELECT ){
+        notUnionAll = 1;
+      }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( pSel->pWin ) return 0;    /* restriction (6b) */
+#endif
+    }
+    if( notUnionAll ){
+      /* If any of the compound arms are connected using UNION, INTERSECT,
+      ** or EXCEPT, then we must ensure that none of the columns use a
+      ** non-BINARY collating sequence. */
+      for(pSel=pSubq; pSel; pSel=pSel->pPrior){
+        int ii;
+        const ExprList *pList = pSel->pEList;
+        assert( pList!=0 );
+        for(ii=0; ii<pList->nExpr; ii++){
+          CollSeq *pColl = sqlite3ExprCollSeq(pParse, pList->a[ii].pExpr);
+          if( !sqlite3IsBinary(pColl) ){
+            return 0;  /* Restriction (8) */
+          }
+        }
+      }
+    }
+  }else{
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( pSubq->pWin && pSubq->pWin->pPartition==0 ) return 0;
+#endif
+  }
+
+#ifdef SQLITE_DEBUG
+  /* Only the first term of a compound can have a WITH clause.  But make
+  ** sure no other terms are marked SF_Recursive in case something changes
+  ** in the future.
+  */
+  {
+    Select *pX;
+    for(pX=pSubq; pX; pX=pX->pPrior){
+      assert( (pX->selFlags & (SF_Recursive))==0 );
+    }
+  }
+#endif
+
+  if( pSubq->pLimit!=0 ){
+    return 0; /* restriction (3) */
+  }
+  while( pWhere->op==TK_AND ){
+    nChng += pushDownWhereTerms(pParse, pSubq, pWhere->pRight, pSrcList, iSrc);
+    pWhere = pWhere->pLeft;
+  }
+
+#if 0 /* These checks now done by sqlite3ExprIsSingleTableConstraint() */
+  if( ExprHasProperty(pWhere, EP_OuterON|EP_InnerON) /* (9a) */
+   && (pSrcList->a[0].fg.jointype & JT_LTORJ)!=0     /* Fast pre-test of (9c) */
+  ){
+    int jj;
+    for(jj=0; jj<iSrc; jj++){
+      if( pWhere->w.iJoin==pSrcList->a[jj].iCursor ){
+        /* If we reach this point, both (9a) and (9b) are satisfied.
+        ** The following loop checks (9c):
+        */
+        for(jj++; jj<iSrc; jj++){
+          if( (pSrcList->a[jj].fg.jointype & JT_RIGHT)!=0 ){
+            return 0;  /* restriction (9) */
+          }
+        }
+      }
+    }
+  }
+  if( isLeftJoin
+   && (ExprHasProperty(pWhere,EP_OuterON)==0
+         || pWhere->w.iJoin!=iCursor)
+  ){
+    return 0; /* restriction (4) */
+  }
+  if( ExprHasProperty(pWhere,EP_OuterON)
+   && pWhere->w.iJoin!=iCursor
+  ){
+    return 0; /* restriction (5) */
+  }
+#endif
+
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+  if( ViewCanHaveRowid && (pWhere->op==TK_ISNULL || pWhere->op==TK_NOTNULL) ){
+    Expr *pLeft = pWhere->pLeft;
+    if( ALWAYS(pLeft)
+     && pLeft->op==TK_COLUMN
+     && pLeft->iColumn < 0
+    ){
+      return 0;  /* Restriction (12) */
+    }
+  }
+#endif
+
+  if( sqlite3ExprIsSingleTableConstraint(pWhere, pSrcList, iSrc, 1) ){
+    nChng++;
+    pSubq->selFlags |= SF_PushDown;
+    while( pSubq ){
+      SubstContext x;
+      pNew = sqlite3ExprDup(pParse->db, pWhere, 0);
+      unsetJoinExpr(pNew, -1, 1);
+      x.pParse = pParse;
+      x.iTable = pSrc->iCursor;
+      x.iNewTable = pSrc->iCursor;
+      x.isOuterJoin = 0;
+      x.pEList = pSubq->pEList;
+      x.pCList = findLeftmostExprlist(pSubq);
+      pNew = substExpr(&x, pNew);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      if( pSubq->pWin && 0==pushDownWindowCheck(pParse, pSubq, pNew) ){
+        /* Restriction 6c has prevented push-down in this case */
+        sqlite3ExprDelete(pParse->db, pNew);
+        nChng--;
+        break;
+      }
+#endif
+      if( pSubq->selFlags & SF_Aggregate ){
+        pSubq->pHaving = sqlite3ExprAnd(pParse, pSubq->pHaving, pNew);
+      }else{
+        pSubq->pWhere = sqlite3ExprAnd(pParse, pSubq->pWhere, pNew);
+      }
+      pSubq = pSubq->pPrior;
+    }
+  }
+  return nChng;
+}
+#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+
+/*
+** Check to see if a subquery contains result-set columns that are
+** never used.  If it does, change the value of those result-set columns
+** to NULL so that they do not cause unnecessary work to compute.
+**
+** Return the number of column that were changed to NULL.
+*/
+static int disableUnusedSubqueryResultColumns(SrcItem *pItem){
+  int nCol;
+  Select *pSub;      /* The subquery to be simplified */
+  Select *pX;        /* For looping over compound elements of pSub */
+  Table *pTab;       /* The table that describes the subquery */
+  int j;             /* Column number */
+  int nChng = 0;     /* Number of columns converted to NULL */
+  Bitmask colUsed;   /* Columns that may not be NULLed out */
+
+  assert( pItem!=0 );
+  if( pItem->fg.isCorrelated || pItem->fg.isCte ){
+    return 0;
+  }
+  assert( pItem->pSTab!=0 );
+  pTab = pItem->pSTab;
+  assert( pItem->fg.isSubquery );
+  pSub = pItem->u4.pSubq->pSelect;
+  assert( pSub->pEList->nExpr==pTab->nCol );
+  for(pX=pSub; pX; pX=pX->pPrior){
+    if( (pX->selFlags & (SF_Distinct|SF_Aggregate))!=0 ){
+      testcase( pX->selFlags & SF_Distinct );
+      testcase( pX->selFlags & SF_Aggregate );
+      return 0;
+    }
+    if( pX->pPrior && pX->op!=TK_ALL ){
+      /* This optimization does not work for compound subqueries that
+      ** use UNION, INTERSECT, or EXCEPT.  Only UNION ALL is allowed. */
+      return 0;
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( pX->pWin ){
+      /* This optimization does not work for subqueries that use window
+      ** functions. */
+      return 0;
+    }
+#endif
+  }
+  colUsed = pItem->colUsed;
+  if( pSub->pOrderBy ){
+    ExprList *pList = pSub->pOrderBy;
+    for(j=0; j<pList->nExpr; j++){
+      u16 iCol = pList->a[j].u.x.iOrderByCol;
+      if( iCol>0 ){
+        iCol--;
+        colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol);
+      }
+    }
+  }
+  nCol = pTab->nCol;
+  for(j=0; j<nCol; j++){
+    Bitmask m = j<BMS-1 ? MASKBIT(j) : TOPBIT;
+    if( (m & colUsed)!=0 ) continue;
+    for(pX=pSub; pX; pX=pX->pPrior) {
+      Expr *pY = pX->pEList->a[j].pExpr;
+      if( pY->op==TK_NULL ) continue;
+      pY->op = TK_NULL;
+      ExprClearProperty(pY, EP_Skip|EP_Unlikely);
+      pX->selFlags |= SF_PushDown;
+      nChng++;
+    }
+  }
+  return nChng;
+}
+
+
+/*
+** The pFunc is the only aggregate function in the query.  Check to see
+** if the query is a candidate for the min/max optimization.
+**
+** If the query is a candidate for the min/max optimization, then set
+** *ppMinMax to be an ORDER BY clause to be used for the optimization
+** and return either WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX depending on
+** whether pFunc is a min() or max() function.
+**
+** If the query is not a candidate for the min/max optimization, return
+** WHERE_ORDERBY_NORMAL (which must be zero).
+**
+** This routine must be called after aggregate functions have been
+** located but before their arguments have been subjected to aggregate
+** analysis.
+*/
+static u8 minMaxQuery(sqlite3 *db, Expr *pFunc, ExprList **ppMinMax){
+  int eRet = WHERE_ORDERBY_NORMAL;      /* Return value */
+  ExprList *pEList;                     /* Arguments to agg function */
+  const char *zFunc;                    /* Name of aggregate function pFunc */
+  ExprList *pOrderBy;
+  u8 sortFlags = 0;
+
+  assert( *ppMinMax==0 );
+  assert( pFunc->op==TK_AGG_FUNCTION );
+  assert( !IsWindowFunc(pFunc) );
+  assert( ExprUseXList(pFunc) );
+  pEList = pFunc->x.pList;
+  if( pEList==0
+   || pEList->nExpr!=1
+   || ExprHasProperty(pFunc, EP_WinFunc)
+   || OptimizationDisabled(db, SQLITE_MinMaxOpt)
+  ){
+    return eRet;
+  }
+  assert( !ExprHasProperty(pFunc, EP_IntValue) );
+  zFunc = pFunc->u.zToken;
+  if( sqlite3StrICmp(zFunc, "min")==0 ){
+    eRet = WHERE_ORDERBY_MIN;
+    if( sqlite3ExprCanBeNull(pEList->a[0].pExpr) ){
+      sortFlags = KEYINFO_ORDER_BIGNULL;
+    }
+  }else if( sqlite3StrICmp(zFunc, "max")==0 ){
+    eRet = WHERE_ORDERBY_MAX;
+    sortFlags = KEYINFO_ORDER_DESC;
+  }else{
+    return eRet;
+  }
+  *ppMinMax = pOrderBy = sqlite3ExprListDup(db, pEList, 0);
+  assert( pOrderBy!=0 || db->mallocFailed );
+  if( pOrderBy ) pOrderBy->a[0].fg.sortFlags = sortFlags;
+  return eRet;
+}
+
+/*
+** The select statement passed as the first argument is an aggregate query.
+** The second argument is the associated aggregate-info object. This
+** function tests if the SELECT is of the form:
+**
+**   SELECT count(*) FROM <tbl>
+**
+** where table is a database table, not a sub-select or view. If the query
+** does match this pattern, then a pointer to the Table object representing
+** <tbl> is returned. Otherwise, NULL is returned.
+**
+** This routine checks to see if it is safe to use the count optimization.
+** A correct answer is still obtained (though perhaps more slowly) if
+** this routine returns NULL when it could have returned a table pointer.
+** But returning the pointer when NULL should have been returned can
+** result in incorrect answers and/or crashes.  So, when in doubt, return NULL.
+*/
+static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
+  Table *pTab;
+  Expr *pExpr;
+
+  assert( !p->pGroupBy );
+
+  if( p->pWhere
+   || p->pEList->nExpr!=1
+   || p->pSrc->nSrc!=1
+   || p->pSrc->a[0].fg.isSubquery
+   || pAggInfo->nFunc!=1
+   || p->pHaving
+  ){
+    return 0;
+  }
+  pTab = p->pSrc->a[0].pSTab;
+  assert( pTab!=0 );
+  assert( !IsView(pTab) );
+  if( !IsOrdinaryTable(pTab) ) return 0;
+  pExpr = p->pEList->a[0].pExpr;
+  assert( pExpr!=0 );
+  if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
+  if( pExpr->pAggInfo!=pAggInfo ) return 0;
+  if( (pAggInfo->aFunc[0].pFunc->funcFlags&SQLITE_FUNC_COUNT)==0 ) return 0;
+  assert( pAggInfo->aFunc[0].pFExpr==pExpr );
+  testcase( ExprHasProperty(pExpr, EP_Distinct) );
+  testcase( ExprHasProperty(pExpr, EP_WinFunc) );
+  if( ExprHasProperty(pExpr, EP_Distinct|EP_WinFunc) ) return 0;
+
+  return pTab;
+}
+
+/*
+** If the source-list item passed as an argument was augmented with an
+** INDEXED BY clause, then try to locate the specified index. If there
+** was such a clause and the named index cannot be found, return
+** SQLITE_ERROR and leave an error in pParse. Otherwise, populate
+** pFrom->pIndex and return SQLITE_OK.
+*/
+SQLITE_PRIVATE int sqlite3IndexedByLookup(Parse *pParse, SrcItem *pFrom){
+  Table *pTab = pFrom->pSTab;
+  char *zIndexedBy = pFrom->u1.zIndexedBy;
+  Index *pIdx;
+  assert( pTab!=0 );
+  assert( pFrom->fg.isIndexedBy!=0 );
+
+  for(pIdx=pTab->pIndex;
+      pIdx && sqlite3StrICmp(pIdx->zName, zIndexedBy);
+      pIdx=pIdx->pNext
+  );
+  if( !pIdx ){
+    sqlite3ErrorMsg(pParse, "no such index: %s", zIndexedBy, 0);
+    pParse->checkSchema = 1;
+    return SQLITE_ERROR;
+  }
+  assert( pFrom->fg.isCte==0 );
+  pFrom->u2.pIBIndex = pIdx;
+  return SQLITE_OK;
+}
+
+/*
+** Detect compound SELECT statements that use an ORDER BY clause with
+** an alternative collating sequence.
+**
+**    SELECT ... FROM t1 EXCEPT SELECT ... FROM t2 ORDER BY .. COLLATE ...
+**
+** These are rewritten as a subquery:
+**
+**    SELECT * FROM (SELECT ... FROM t1 EXCEPT SELECT ... FROM t2)
+**     ORDER BY ... COLLATE ...
+**
+** This transformation is necessary because the multiSelectOrderBy() routine
+** above that generates the code for a compound SELECT with an ORDER BY clause
+** uses a merge algorithm that requires the same collating sequence on the
+** result columns as on the ORDER BY clause.  See ticket
+** http://www.sqlite.org/src/info/6709574d2a
+**
+** This transformation is only needed for EXCEPT, INTERSECT, and UNION.
+** The UNION ALL operator works fine with multiSelectOrderBy() even when
+** there are COLLATE terms in the ORDER BY.
+*/
+static int convertCompoundSelectToSubquery(Walker *pWalker, Select *p){
+  int i;
+  Select *pNew;
+  Select *pX;
+  sqlite3 *db;
+  struct ExprList_item *a;
+  SrcList *pNewSrc;
+  Parse *pParse;
+  Token dummy;
+
+  if( p->pPrior==0 ) return WRC_Continue;
+  if( p->pOrderBy==0 ) return WRC_Continue;
+  for(pX=p; pX && (pX->op==TK_ALL || pX->op==TK_SELECT); pX=pX->pPrior){}
+  if( pX==0 ) return WRC_Continue;
+  a = p->pOrderBy->a;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  /* If iOrderByCol is already non-zero, then it has already been matched
+  ** to a result column of the SELECT statement. This occurs when the
+  ** SELECT is rewritten for window-functions processing and then passed
+  ** to sqlite3SelectPrep() and similar a second time. The rewriting done
+  ** by this function is not required in this case. */
+  if( a[0].u.x.iOrderByCol ) return WRC_Continue;
+#endif
+  for(i=p->pOrderBy->nExpr-1; i>=0; i--){
+    if( a[i].pExpr->flags & EP_Collate ) break;
+  }
+  if( i<0 ) return WRC_Continue;
+
+  /* If we reach this point, that means the transformation is required. */
+
+  pParse = pWalker->pParse;
+  db = pParse->db;
+  pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
+  if( pNew==0 ) return WRC_Abort;
+  memset(&dummy, 0, sizeof(dummy));
+  pNewSrc = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&dummy,pNew,0);
+  assert( pNewSrc!=0 || pParse->nErr );
+  if( pParse->nErr ){
+    sqlite3SrcListDelete(db, pNewSrc);
+    return WRC_Abort;
+  }
+  *pNew = *p;
+  p->pSrc = pNewSrc;
+  p->pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ASTERISK, 0));
+  p->op = TK_SELECT;
+  p->pWhere = 0;
+  pNew->pGroupBy = 0;
+  pNew->pHaving = 0;
+  pNew->pOrderBy = 0;
+  p->pPrior = 0;
+  p->pNext = 0;
+  p->pWith = 0;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  p->pWinDefn = 0;
+#endif
+  p->selFlags &= ~SF_Compound;
+  assert( (p->selFlags & SF_Converted)==0 );
+  p->selFlags |= SF_Converted;
+  assert( pNew->pPrior!=0 );
+  pNew->pPrior->pNext = pNew;
+  pNew->pLimit = 0;
+  return WRC_Continue;
+}
+
+/*
+** Check to see if the FROM clause term pFrom has table-valued function
+** arguments.  If it does, leave an error message in pParse and return
+** non-zero, since pFrom is not allowed to be a table-valued function.
+*/
+static int cannotBeFunction(Parse *pParse, SrcItem *pFrom){
+  if( pFrom->fg.isTabFunc ){
+    sqlite3ErrorMsg(pParse, "'%s' is not a function", pFrom->zName);
+    return 1;
+  }
+  return 0;
+}
+
+#ifndef SQLITE_OMIT_CTE
+/*
+** Argument pWith (which may be NULL) points to a linked list of nested
+** WITH contexts, from inner to outermost. If the table identified by
+** FROM clause element pItem is really a common-table-expression (CTE)
+** then return a pointer to the CTE definition for that table. Otherwise
+** return NULL.
+**
+** If a non-NULL value is returned, set *ppContext to point to the With
+** object that the returned CTE belongs to.
+*/
+static struct Cte *searchWith(
+  With *pWith,                    /* Current innermost WITH clause */
+  SrcItem *pItem,                 /* FROM clause element to resolve */
+  With **ppContext                /* OUT: WITH clause return value belongs to */
+){
+  const char *zName = pItem->zName;
+  With *p;
+  assert( pItem->fg.fixedSchema || pItem->u4.zDatabase==0 );
+  assert( zName!=0 );
+  for(p=pWith; p; p=p->pOuter){
+    int i;
+    for(i=0; i<p->nCte; i++){
+      if( sqlite3StrICmp(zName, p->a[i].zName)==0 ){
+        *ppContext = p;
+        return &p->a[i];
+      }
+    }
+    if( p->bView ) break;
+  }
+  return 0;
+}
+
+/* The code generator maintains a stack of active WITH clauses
+** with the inner-most WITH clause being at the top of the stack.
+**
+** This routine pushes the WITH clause passed as the second argument
+** onto the top of the stack. If argument bFree is true, then this
+** WITH clause will never be popped from the stack but should instead
+** be freed along with the Parse object. In other cases, when
+** bFree==0, the With object will be freed along with the SELECT
+** statement with which it is associated.
+**
+** This routine returns a copy of pWith.  Or, if bFree is true and
+** the pWith object is destroyed immediately due to an OOM condition,
+** then this routine return NULL.
+**
+** If bFree is true, do not continue to use the pWith pointer after
+** calling this routine,  Instead, use only the return value.
+*/
+SQLITE_PRIVATE With *sqlite3WithPush(Parse *pParse, With *pWith, u8 bFree){
+  if( pWith ){
+    if( bFree ){
+      pWith = (With*)sqlite3ParserAddCleanup(pParse, sqlite3WithDeleteGeneric,
+                      pWith);
+      if( pWith==0 ) return 0;
+    }
+    if( pParse->nErr==0 ){
+      assert( pParse->pWith!=pWith );
+      pWith->pOuter = pParse->pWith;
+      pParse->pWith = pWith;
+    }
+  }
+  return pWith;
+}
+
+/*
+** This function checks if argument pFrom refers to a CTE declared by
+** a WITH clause on the stack currently maintained by the parser (on the
+** pParse->pWith linked list).  And if currently processing a CTE
+** CTE expression, through routine checks to see if the reference is
+** a recursive reference to the CTE.
+**
+** If pFrom matches a CTE according to either of these two above, pFrom->pTab
+** and other fields are populated accordingly.
+**
+** Return 0 if no match is found.
+** Return 1 if a match is found.
+** Return 2 if an error condition is detected.
+*/
+static int resolveFromTermToCte(
+  Parse *pParse,                  /* The parsing context */
+  Walker *pWalker,                /* Current tree walker */
+  SrcItem *pFrom                  /* The FROM clause term to check */
+){
+  Cte *pCte;               /* Matched CTE (or NULL if no match) */
+  With *pWith;             /* The matching WITH */
+
+  assert( pFrom->pSTab==0 );
+  if( pParse->pWith==0 ){
+    /* There are no WITH clauses in the stack.  No match is possible */
+    return 0;
+  }
+  if( pParse->nErr ){
+    /* Prior errors might have left pParse->pWith in a goofy state, so
+    ** go no further. */
+    return 0;
+  }
+  assert( pFrom->fg.hadSchema==0 || pFrom->fg.notCte!=0 );
+  if( pFrom->fg.fixedSchema==0 && pFrom->u4.zDatabase!=0 ){
+    /* The FROM term contains a schema qualifier (ex: main.t1) and so
+    ** it cannot possibly be a CTE reference. */
+    return 0;
+  }
+  if( pFrom->fg.notCte ){
+    /* The FROM term is specifically excluded from matching a CTE.
+    **   (1)  It is part of a trigger that used to have zDatabase but had
+    **        zDatabase removed by sqlite3FixTriggerStep().
+    **   (2)  This is the first term in the FROM clause of an UPDATE.
+    */
+    return 0;
+  }
+  pCte = searchWith(pParse->pWith, pFrom, &pWith);
+  if( pCte ){
+    sqlite3 *db = pParse->db;
+    Table *pTab;
+    ExprList *pEList;
+    Select *pSel;
+    Select *pLeft;                /* Left-most SELECT statement */
+    Select *pRecTerm;             /* Left-most recursive term */
+    int bMayRecursive;            /* True if compound joined by UNION [ALL] */
+    With *pSavedWith;             /* Initial value of pParse->pWith */
+    int iRecTab = -1;             /* Cursor for recursive table */
+    CteUse *pCteUse;
+
+    /* If pCte->zCteErr is non-NULL at this point, then this is an illegal
+    ** recursive reference to CTE pCte. Leave an error in pParse and return
+    ** early. If pCte->zCteErr is NULL, then this is not a recursive reference.
+    ** In this case, proceed.  */
+    if( pCte->zCteErr ){
+      sqlite3ErrorMsg(pParse, pCte->zCteErr, pCte->zName);
+      return 2;
+    }
+    if( cannotBeFunction(pParse, pFrom) ) return 2;
+
+    assert( pFrom->pSTab==0 );
+    pTab = sqlite3DbMallocZero(db, sizeof(Table));
+    if( pTab==0 ) return 2;
+    pCteUse = pCte->pUse;
+    if( pCteUse==0 ){
+      pCte->pUse = pCteUse = sqlite3DbMallocZero(db, sizeof(pCteUse[0]));
+      if( pCteUse==0
+       || sqlite3ParserAddCleanup(pParse,sqlite3DbFree,pCteUse)==0
+      ){
+        sqlite3DbFree(db, pTab);
+        return 2;
+      }
+      pCteUse->eM10d = pCte->eM10d;
+    }
+    pFrom->pSTab = pTab;
+    pTab->nTabRef = 1;
+    pTab->zName = sqlite3DbStrDup(db, pCte->zName);
+    pTab->iPKey = -1;
+    pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
+    pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid;
+    sqlite3SrcItemAttachSubquery(pParse, pFrom, pCte->pSelect, 1);
+    if( db->mallocFailed ) return 2;
+    assert( pFrom->fg.isSubquery && pFrom->u4.pSubq );
+    pSel = pFrom->u4.pSubq->pSelect;
+    assert( pSel!=0 );
+    pSel->selFlags |= SF_CopyCte;
+    if( pFrom->fg.isIndexedBy ){
+      sqlite3ErrorMsg(pParse, "no such index: \"%s\"", pFrom->u1.zIndexedBy);
+      return 2;
+    }
+    assert( !pFrom->fg.isIndexedBy );
+    pFrom->fg.isCte = 1;
+    pFrom->u2.pCteUse = pCteUse;
+    pCteUse->nUse++;
+
+    /* Check if this is a recursive CTE. */
+    pRecTerm = pSel;
+    bMayRecursive = ( pSel->op==TK_ALL || pSel->op==TK_UNION );
+    while( bMayRecursive && pRecTerm->op==pSel->op ){
+      int i;
+      SrcList *pSrc = pRecTerm->pSrc;
+      assert( pRecTerm->pPrior!=0 );
+      for(i=0; i<pSrc->nSrc; i++){
+        SrcItem *pItem = &pSrc->a[i];
+        if( pItem->zName!=0
+         && !pItem->fg.hadSchema
+         && ALWAYS( !pItem->fg.isSubquery )
+         && (pItem->fg.fixedSchema || pItem->u4.zDatabase==0)
+         && 0==sqlite3StrICmp(pItem->zName, pCte->zName)
+        ){
+          pItem->pSTab = pTab;
+          pTab->nTabRef++;
+          pItem->fg.isRecursive = 1;
+          if( pRecTerm->selFlags & SF_Recursive ){
+            sqlite3ErrorMsg(pParse,
+               "multiple references to recursive table: %s", pCte->zName
+            );
+            return 2;
+          }
+          pRecTerm->selFlags |= SF_Recursive;
+          if( iRecTab<0 ) iRecTab = pParse->nTab++;
+          pItem->iCursor = iRecTab;
+        }
+      }
+      if( (pRecTerm->selFlags & SF_Recursive)==0 ) break;
+      pRecTerm = pRecTerm->pPrior;
+    }
+
+    pCte->zCteErr = "circular reference: %s";
+    pSavedWith = pParse->pWith;
+    pParse->pWith = pWith;
+    if( pSel->selFlags & SF_Recursive ){
+      int rc;
+      assert( pRecTerm!=0 );
+      assert( (pRecTerm->selFlags & SF_Recursive)==0 );
+      assert( pRecTerm->pNext!=0 );
+      assert( (pRecTerm->pNext->selFlags & SF_Recursive)!=0 );
+      assert( pRecTerm->pWith==0 );
+      pRecTerm->pWith = pSel->pWith;
+      rc = sqlite3WalkSelect(pWalker, pRecTerm);
+      pRecTerm->pWith = 0;
+      if( rc ){
+        pParse->pWith = pSavedWith;
+        return 2;
+      }
+    }else{
+      if( sqlite3WalkSelect(pWalker, pSel) ){
+        pParse->pWith = pSavedWith;
+        return 2;
+      }
+    }
+    pParse->pWith = pWith;
+
+    for(pLeft=pSel; pLeft->pPrior; pLeft=pLeft->pPrior);
+    pEList = pLeft->pEList;
+    if( pCte->pCols ){
+      if( pEList && pEList->nExpr!=pCte->pCols->nExpr ){
+        sqlite3ErrorMsg(pParse, "table %s has %d values for %d columns",
+            pCte->zName, pEList->nExpr, pCte->pCols->nExpr
+        );
+        pParse->pWith = pSavedWith;
+        return 2;
+      }
+      pEList = pCte->pCols;
+    }
+
+    sqlite3ColumnsFromExprList(pParse, pEList, &pTab->nCol, &pTab->aCol);
+    if( bMayRecursive ){
+      if( pSel->selFlags & SF_Recursive ){
+        pCte->zCteErr = "multiple recursive references: %s";
+      }else{
+        pCte->zCteErr = "recursive reference in a subquery: %s";
+      }
+      sqlite3WalkSelect(pWalker, pSel);
+    }
+    pCte->zCteErr = 0;
+    pParse->pWith = pSavedWith;
+    return 1;  /* Success */
+  }
+  return 0;  /* No match */
+}
+#endif
+
+#ifndef SQLITE_OMIT_CTE
+/*
+** If the SELECT passed as the second argument has an associated WITH
+** clause, pop it from the stack stored as part of the Parse object.
+**
+** This function is used as the xSelectCallback2() callback by
+** sqlite3SelectExpand() when walking a SELECT tree to resolve table
+** names and other FROM clause elements.
+*/
+SQLITE_PRIVATE void sqlite3SelectPopWith(Walker *pWalker, Select *p){
+  Parse *pParse = pWalker->pParse;
+  if( OK_IF_ALWAYS_TRUE(pParse->pWith) && p->pPrior==0 ){
+    With *pWith = findRightmost(p)->pWith;
+    if( pWith!=0 ){
+      assert( pParse->pWith==pWith || pParse->nErr );
+      pParse->pWith = pWith->pOuter;
+    }
+  }
+}
+#endif
+
+/*
+** The SrcItem structure passed as the second argument represents a
+** sub-query in the FROM clause of a SELECT statement. This function
+** allocates and populates the SrcItem.pTab object. If successful,
+** SQLITE_OK is returned. Otherwise, if an OOM error is encountered,
+** SQLITE_NOMEM.
+*/
+SQLITE_PRIVATE int sqlite3ExpandSubquery(Parse *pParse, SrcItem *pFrom){
+  Select *pSel;
+  Table *pTab;
+
+  assert( pFrom->fg.isSubquery );
+  assert( pFrom->u4.pSubq!=0 );
+  pSel = pFrom->u4.pSubq->pSelect;
+  assert( pSel );
+  pFrom->pSTab = pTab = sqlite3DbMallocZero(pParse->db, sizeof(Table));
+  if( pTab==0 ) return SQLITE_NOMEM;
+  pTab->nTabRef = 1;
+  if( pFrom->zAlias ){
+    pTab->zName = sqlite3DbStrDup(pParse->db, pFrom->zAlias);
+  }else{
+    pTab->zName = sqlite3MPrintf(pParse->db, "%!S", pFrom);
+  }
+  while( pSel->pPrior ){ pSel = pSel->pPrior; }
+  sqlite3ColumnsFromExprList(pParse, pSel->pEList,&pTab->nCol,&pTab->aCol);
+  pTab->iPKey = -1;
+  pTab->eTabType = TABTYP_VIEW;
+  pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
+#ifndef SQLITE_ALLOW_ROWID_IN_VIEW
+  /* The usual case - do not allow ROWID on a subquery */
+  pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid;
+#else
+  /* Legacy compatibility mode */
+  pTab->tabFlags |= TF_Ephemeral | sqlite3Config.mNoVisibleRowid;
+#endif
+  return pParse->nErr ? SQLITE_ERROR : SQLITE_OK;
+}
+
+
+/*
+** Check the N SrcItem objects to the right of pBase.  (N might be zero!)
+** If any of those SrcItem objects have a USING clause containing zName
+** then return true.
+**
+** If N is zero, or none of the N SrcItem objects to the right of pBase
+** contains a USING clause, or if none of the USING clauses contain zName,
+** then return false.
+*/
+static int inAnyUsingClause(
+  const char *zName, /* Name we are looking for */
+  SrcItem *pBase,    /* The base SrcItem.  Looking at pBase[1] and following */
+  int N              /* How many SrcItems to check */
+){
+  while( N>0 ){
+    N--;
+    pBase++;
+    if( pBase->fg.isUsing==0 ) continue;
+    if( NEVER(pBase->u3.pUsing==0) ) continue;
+    if( sqlite3IdListIndex(pBase->u3.pUsing, zName)>=0 ) return 1;
+  }
+  return 0;
+}
+
+
+/*
+** This routine is a Walker callback for "expanding" a SELECT statement.
+** "Expanding" means to do the following:
+**
+**    (1)  Make sure VDBE cursor numbers have been assigned to every
+**         element of the FROM clause.
+**
+**    (2)  Fill in the pTabList->a[].pTab fields in the SrcList that
+**         defines FROM clause.  When views appear in the FROM clause,
+**         fill pTabList->a[].pSelect with a copy of the SELECT statement
+**         that implements the view.  A copy is made of the view's SELECT
+**         statement so that we can freely modify or delete that statement
+**         without worrying about messing up the persistent representation
+**         of the view.
+**
+**    (3)  Add terms to the WHERE clause to accommodate the NATURAL keyword
+**         on joins and the ON and USING clause of joins.
+**
+**    (4)  Scan the list of columns in the result set (pEList) looking
+**         for instances of the "*" operator or the TABLE.* operator.
+**         If found, expand each "*" to be every column in every table
+**         and TABLE.* to be every column in TABLE.
+**
+*/
+static int selectExpander(Walker *pWalker, Select *p){
+  Parse *pParse = pWalker->pParse;
+  int i, j, k, rc;
+  SrcList *pTabList;
+  ExprList *pEList;
+  SrcItem *pFrom;
+  sqlite3 *db = pParse->db;
+  Expr *pE, *pRight, *pExpr;
+  u16 selFlags = p->selFlags;
+  u32 elistFlags = 0;
+
+  p->selFlags |= SF_Expanded;
+  if( db->mallocFailed  ){
+    return WRC_Abort;
+  }
+  assert( p->pSrc!=0 );
+  if( (selFlags & SF_Expanded)!=0 ){
+    return WRC_Prune;
+  }
+  if( pWalker->eCode ){
+    /* Renumber selId because it has been copied from a view */
+    p->selId = ++pParse->nSelect;
+  }
+  pTabList = p->pSrc;
+  pEList = p->pEList;
+  if( pParse->pWith && (p->selFlags & SF_View) ){
+    if( p->pWith==0 ){
+      p->pWith = (With*)sqlite3DbMallocZero(db, sizeof(With));
+      if( p->pWith==0 ){
+        return WRC_Abort;
+      }
+    }
+    p->pWith->bView = 1;
+  }
+  sqlite3WithPush(pParse, p->pWith, 0);
+
+  /* Make sure cursor numbers have been assigned to all entries in
+  ** the FROM clause of the SELECT statement.
+  */
+  sqlite3SrcListAssignCursors(pParse, pTabList);
+
+  /* Look up every table named in the FROM clause of the select.  If
+  ** an entry of the FROM clause is a subquery instead of a table or view,
+  ** then create a transient table structure to describe the subquery.
+  */
+  for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+    Table *pTab;
+    assert( pFrom->fg.isRecursive==0 || pFrom->pSTab!=0 );
+    if( pFrom->pSTab ) continue;
+    assert( pFrom->fg.isRecursive==0 );
+    if( pFrom->zName==0 ){
+#ifndef SQLITE_OMIT_SUBQUERY
+      Select *pSel;
+      assert( pFrom->fg.isSubquery && pFrom->u4.pSubq!=0 );
+      pSel = pFrom->u4.pSubq->pSelect;
+      /* A sub-query in the FROM clause of a SELECT */
+      assert( pSel!=0 );
+      assert( pFrom->pSTab==0 );
+      if( sqlite3WalkSelect(pWalker, pSel) ) return WRC_Abort;
+      if( sqlite3ExpandSubquery(pParse, pFrom) ) return WRC_Abort;
+#endif
+#ifndef SQLITE_OMIT_CTE
+    }else if( (rc = resolveFromTermToCte(pParse, pWalker, pFrom))!=0 ){
+      if( rc>1 ) return WRC_Abort;
+      pTab = pFrom->pSTab;
+      assert( pTab!=0 );
+#endif
+    }else{
+      /* An ordinary table or view name in the FROM clause */
+      assert( pFrom->pSTab==0 );
+      pFrom->pSTab = pTab = sqlite3LocateTableItem(pParse, 0, pFrom);
+      if( pTab==0 ) return WRC_Abort;
+      if( pTab->nTabRef>=0xffff ){
+        sqlite3ErrorMsg(pParse, "too many references to \"%s\": max 65535",
+           pTab->zName);
+        pFrom->pSTab = 0;
+        return WRC_Abort;
+      }
+      pTab->nTabRef++;
+      if( !IsVirtual(pTab) && cannotBeFunction(pParse, pFrom) ){
+        return WRC_Abort;
+      }
+#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
+      if( !IsOrdinaryTable(pTab) ){
+        i16 nCol;
+        u8 eCodeOrig = pWalker->eCode;
+        if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
+        assert( pFrom->fg.isSubquery==0 );
+        if( IsView(pTab) ){
+          if( (db->flags & SQLITE_EnableView)==0
+           && pTab->pSchema!=db->aDb[1].pSchema
+          ){
+            sqlite3ErrorMsg(pParse, "access to view \"%s\" prohibited",
+              pTab->zName);
+          }
+          sqlite3SrcItemAttachSubquery(pParse, pFrom, pTab->u.view.pSelect, 1);
+        }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+        else if( ALWAYS(IsVirtual(pTab))
+         && pFrom->fg.fromDDL
+         && ALWAYS(pTab->u.vtab.p!=0)
+         && pTab->u.vtab.p->eVtabRisk > ((db->flags & SQLITE_TrustedSchema)!=0)
+        ){
+          sqlite3ErrorMsg(pParse, "unsafe use of virtual table \"%s\"",
+                                  pTab->zName);
+        }
+        assert( SQLITE_VTABRISK_Normal==1 && SQLITE_VTABRISK_High==2 );
+#endif
+        nCol = pTab->nCol;
+        pTab->nCol = -1;
+        pWalker->eCode = 1;  /* Turn on Select.selId renumbering */
+        if( pFrom->fg.isSubquery ){
+          sqlite3WalkSelect(pWalker, pFrom->u4.pSubq->pSelect);
+        }
+        pWalker->eCode = eCodeOrig;
+        pTab->nCol = nCol;
+      }
+#endif
+    }
+
+    /* Locate the index named by the INDEXED BY clause, if any. */
+    if( pFrom->fg.isIndexedBy && sqlite3IndexedByLookup(pParse, pFrom) ){
+      return WRC_Abort;
+    }
+  }
+
+  /* Process NATURAL keywords, and ON and USING clauses of joins.
+  */
+  assert( db->mallocFailed==0 || pParse->nErr!=0 );
+  if( pParse->nErr || sqlite3ProcessJoin(pParse, p) ){
+    return WRC_Abort;
+  }
+
+  /* For every "*" that occurs in the column list, insert the names of
+  ** all columns in all tables.  And for every TABLE.* insert the names
+  ** of all columns in TABLE.  The parser inserted a special expression
+  ** with the TK_ASTERISK operator for each "*" that it found in the column
+  ** list.  The following code just has to locate the TK_ASTERISK
+  ** expressions and expand each one to the list of all columns in
+  ** all tables.
+  **
+  ** The first loop just checks to see if there are any "*" operators
+  ** that need expanding.
+  */
+  for(k=0; k<pEList->nExpr; k++){
+    pE = pEList->a[k].pExpr;
+    if( pE->op==TK_ASTERISK ) break;
+    assert( pE->op!=TK_DOT || pE->pRight!=0 );
+    assert( pE->op!=TK_DOT || (pE->pLeft!=0 && pE->pLeft->op==TK_ID) );
+    if( pE->op==TK_DOT && pE->pRight->op==TK_ASTERISK ) break;
+    elistFlags |= pE->flags;
+  }
+  if( k<pEList->nExpr ){
+    /*
+    ** If we get here it means the result set contains one or more "*"
+    ** operators that need to be expanded.  Loop through each expression
+    ** in the result set and expand them one by one.
+    */
+    struct ExprList_item *a = pEList->a;
+    ExprList *pNew = 0;
+    int flags = pParse->db->flags;
+    int longNames = (flags & SQLITE_FullColNames)!=0
+                      && (flags & SQLITE_ShortColNames)==0;
+
+    for(k=0; k<pEList->nExpr; k++){
+      pE = a[k].pExpr;
+      elistFlags |= pE->flags;
+      pRight = pE->pRight;
+      assert( pE->op!=TK_DOT || pRight!=0 );
+      if( pE->op!=TK_ASTERISK
+       && (pE->op!=TK_DOT || pRight->op!=TK_ASTERISK)
+      ){
+        /* This particular expression does not need to be expanded.
+        */
+        pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr);
+        if( pNew ){
+          pNew->a[pNew->nExpr-1].zEName = a[k].zEName;
+          pNew->a[pNew->nExpr-1].fg.eEName = a[k].fg.eEName;
+          a[k].zEName = 0;
+        }
+        a[k].pExpr = 0;
+      }else{
+        /* This expression is a "*" or a "TABLE.*" and needs to be
+        ** expanded. */
+        int tableSeen = 0;      /* Set to 1 when TABLE matches */
+        char *zTName = 0;       /* text of name of TABLE */
+        int iErrOfst;
+        if( pE->op==TK_DOT ){
+          assert( (selFlags & SF_NestedFrom)==0 );
+          assert( pE->pLeft!=0 );
+          assert( !ExprHasProperty(pE->pLeft, EP_IntValue) );
+          zTName = pE->pLeft->u.zToken;
+          assert( ExprUseWOfst(pE->pLeft) );
+          iErrOfst = pE->pRight->w.iOfst;
+        }else{
+          assert( ExprUseWOfst(pE) );
+          iErrOfst = pE->w.iOfst;
+        }
+        for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+          int nAdd;                    /* Number of cols including rowid */
+          Table *pTab = pFrom->pSTab;  /* Table for this data source */
+          ExprList *pNestedFrom;       /* Result-set of a nested FROM clause */
+          char *zTabName;              /* AS name for this data source */
+          const char *zSchemaName = 0; /* Schema name for this data source */
+          int iDb;                     /* Schema index for this data src */
+          IdList *pUsing;              /* USING clause for pFrom[1] */
+
+          if( (zTabName = pFrom->zAlias)==0 ){
+            zTabName = pTab->zName;
+          }
+          if( db->mallocFailed ) break;
+          assert( (int)pFrom->fg.isNestedFrom == IsNestedFrom(pFrom) );
+          if( pFrom->fg.isNestedFrom ){
+            assert( pFrom->fg.isSubquery && pFrom->u4.pSubq );
+            assert( pFrom->u4.pSubq->pSelect!=0 );
+            pNestedFrom = pFrom->u4.pSubq->pSelect->pEList;
+            assert( pNestedFrom!=0 );
+            assert( pNestedFrom->nExpr==pTab->nCol );
+            assert( VisibleRowid(pTab)==0 || ViewCanHaveRowid );
+          }else{
+            if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){
+              continue;
+            }
+            pNestedFrom = 0;
+            iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+            zSchemaName = iDb>=0 ? db->aDb[iDb].zDbSName : "*";
+          }
+          if( i+1<pTabList->nSrc
+           && pFrom[1].fg.isUsing
+           && (selFlags & SF_NestedFrom)!=0
+          ){
+            int ii;
+            pUsing = pFrom[1].u3.pUsing;
+            for(ii=0; ii<pUsing->nId; ii++){
+              const char *zUName = pUsing->a[ii].zName;
+              pRight = sqlite3Expr(db, TK_ID, zUName);
+              sqlite3ExprSetErrorOffset(pRight, iErrOfst);
+              pNew = sqlite3ExprListAppend(pParse, pNew, pRight);
+              if( pNew ){
+                struct ExprList_item *pX = &pNew->a[pNew->nExpr-1];
+                assert( pX->zEName==0 );
+                pX->zEName = sqlite3MPrintf(db,"..%s", zUName);
+                pX->fg.eEName = ENAME_TAB;
+                pX->fg.bUsingTerm = 1;
+              }
+            }
+          }else{
+            pUsing = 0;
+          }
+
+          nAdd = pTab->nCol;
+          if( VisibleRowid(pTab) && (selFlags & SF_NestedFrom)!=0 ) nAdd++;
+          for(j=0; j<nAdd; j++){
+            const char *zName;
+            struct ExprList_item *pX; /* Newly added ExprList term */
+
+            if( j==pTab->nCol ){
+              zName = sqlite3RowidAlias(pTab);
+              if( zName==0 ) continue;
+            }else{
+              zName = pTab->aCol[j].zCnName;
+
+              /* If pTab is actually an SF_NestedFrom sub-select, do not
+              ** expand any ENAME_ROWID columns.  */
+              if( pNestedFrom && pNestedFrom->a[j].fg.eEName==ENAME_ROWID ){
+                continue;
+              }
+
+              if( zTName
+               && pNestedFrom
+               && sqlite3MatchEName(&pNestedFrom->a[j], 0, zTName, 0, 0)==0
+              ){
+                continue;
+              }
+
+              /* If a column is marked as 'hidden', omit it from the expanded
+              ** result-set list unless the SELECT has the SF_IncludeHidden
+              ** bit set.
+              */
+              if( (p->selFlags & SF_IncludeHidden)==0
+                && IsHiddenColumn(&pTab->aCol[j])
+              ){
+                continue;
+              }
+              if( (pTab->aCol[j].colFlags & COLFLAG_NOEXPAND)!=0
+               && zTName==0
+               && (selFlags & (SF_NestedFrom))==0
+              ){
+                continue;
+              }
+            }
+            assert( zName );
+            tableSeen = 1;
+
+            if( i>0 && zTName==0 && (selFlags & SF_NestedFrom)==0 ){
+              if( pFrom->fg.isUsing
+               && sqlite3IdListIndex(pFrom->u3.pUsing, zName)>=0
+              ){
+                /* In a join with a USING clause, omit columns in the
+                ** using clause from the table on the right. */
+                continue;
+              }
+            }
+            pRight = sqlite3Expr(db, TK_ID, zName);
+            if( (pTabList->nSrc>1
+                 && (  (pFrom->fg.jointype & JT_LTORJ)==0
+                     || (selFlags & SF_NestedFrom)!=0
+                     || !inAnyUsingClause(zName,pFrom,pTabList->nSrc-i-1)
+                    )
+                )
+             || IN_RENAME_OBJECT
+            ){
+              Expr *pLeft;
+              pLeft = sqlite3Expr(db, TK_ID, zTabName);
+              pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight);
+              if( IN_RENAME_OBJECT && pE->pLeft ){
+                sqlite3RenameTokenRemap(pParse, pLeft, pE->pLeft);
+              }
+              if( zSchemaName ){
+                pLeft = sqlite3Expr(db, TK_ID, zSchemaName);
+                pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pExpr);
+              }
+            }else{
+              pExpr = pRight;
+            }
+            sqlite3ExprSetErrorOffset(pExpr, iErrOfst);
+            pNew = sqlite3ExprListAppend(pParse, pNew, pExpr);
+            if( pNew==0 ){
+              break;  /* OOM */
+            }
+            pX = &pNew->a[pNew->nExpr-1];
+            assert( pX->zEName==0 );
+            if( (selFlags & SF_NestedFrom)!=0 && !IN_RENAME_OBJECT ){
+              if( pNestedFrom && (!ViewCanHaveRowid || j<pNestedFrom->nExpr) ){
+                assert( j<pNestedFrom->nExpr );
+                pX->zEName = sqlite3DbStrDup(db, pNestedFrom->a[j].zEName);
+                testcase( pX->zEName==0 );
+              }else{
+                pX->zEName = sqlite3MPrintf(db, "%s.%s.%s",
+                                           zSchemaName, zTabName, zName);
+                testcase( pX->zEName==0 );
+              }
+              pX->fg.eEName = (j==pTab->nCol ? ENAME_ROWID : ENAME_TAB);
+              if( (pFrom->fg.isUsing
+                   && sqlite3IdListIndex(pFrom->u3.pUsing, zName)>=0)
+               || (pUsing && sqlite3IdListIndex(pUsing, zName)>=0)
+               || (j<pTab->nCol && (pTab->aCol[j].colFlags & COLFLAG_NOEXPAND))
+              ){
+                pX->fg.bNoExpand = 1;
+              }
+            }else if( longNames ){
+              pX->zEName = sqlite3MPrintf(db, "%s.%s", zTabName, zName);
+              pX->fg.eEName = ENAME_NAME;
+            }else{
+              pX->zEName = sqlite3DbStrDup(db, zName);
+              pX->fg.eEName = ENAME_NAME;
+            }
+          }
+        }
+        if( !tableSeen ){
+          if( zTName ){
+            sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
+          }else{
+            sqlite3ErrorMsg(pParse, "no tables specified");
+          }
+        }
+      }
+    }
+    sqlite3ExprListDelete(db, pEList);
+    p->pEList = pNew;
+  }
+  if( p->pEList ){
+    if( p->pEList->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
+      sqlite3ErrorMsg(pParse, "too many columns in result set");
+      return WRC_Abort;
+    }
+    if( (elistFlags & (EP_HasFunc|EP_Subquery))!=0 ){
+      p->selFlags |= SF_ComplexResult;
+    }
+  }
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x8 ){
+    TREETRACE(0x8,pParse,p,("After result-set wildcard expansion:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+  return WRC_Continue;
+}
+
+#if SQLITE_DEBUG
+/*
+** Always assert.  This xSelectCallback2 implementation proves that the
+** xSelectCallback2 is never invoked.
+*/
+SQLITE_PRIVATE void sqlite3SelectWalkAssert2(Walker *NotUsed, Select *NotUsed2){
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  assert( 0 );
+}
+#endif
+/*
+** This routine "expands" a SELECT statement and all of its subqueries.
+** For additional information on what it means to "expand" a SELECT
+** statement, see the comment on the selectExpand worker callback above.
+**
+** Expanding a SELECT statement is the first step in processing a
+** SELECT statement.  The SELECT statement must be expanded before
+** name resolution is performed.
+**
+** If anything goes wrong, an error message is written into pParse.
+** The calling function can detect the problem by looking at pParse->nErr
+** and/or pParse->db->mallocFailed.
+*/
+static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){
+  Walker w;
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.pParse = pParse;
+  if( OK_IF_ALWAYS_TRUE(pParse->hasCompound) ){
+    w.xSelectCallback = convertCompoundSelectToSubquery;
+    w.xSelectCallback2 = 0;
+    sqlite3WalkSelect(&w, pSelect);
+  }
+  w.xSelectCallback = selectExpander;
+  w.xSelectCallback2 = sqlite3SelectPopWith;
+  w.eCode = 0;
+  sqlite3WalkSelect(&w, pSelect);
+}
+
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** This is a Walker.xSelectCallback callback for the sqlite3SelectTypeInfo()
+** interface.
+**
+** For each FROM-clause subquery, add Column.zType, Column.zColl, and
+** Column.affinity information to the Table structure that represents
+** the result set of that subquery.
+**
+** The Table structure that represents the result set was constructed
+** by selectExpander() but the type and collation and affinity information
+** was omitted at that point because identifiers had not yet been resolved.
+** This routine is called after identifier resolution.
+*/
+static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
+  Parse *pParse;
+  int i;
+  SrcList *pTabList;
+  SrcItem *pFrom;
+
+  if( p->selFlags & SF_HasTypeInfo ) return;
+  p->selFlags |= SF_HasTypeInfo;
+  pParse = pWalker->pParse;
+  assert( (p->selFlags & SF_Resolved) );
+  pTabList = p->pSrc;
+  for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+    Table *pTab = pFrom->pSTab;
+    assert( pTab!=0 );
+    if( (pTab->tabFlags & TF_Ephemeral)!=0 && pFrom->fg.isSubquery ){
+      /* A sub-query in the FROM clause of a SELECT */
+      Select *pSel = pFrom->u4.pSubq->pSelect;
+      sqlite3SubqueryColumnTypes(pParse, pTab, pSel, SQLITE_AFF_NONE);
+    }
+  }
+}
+#endif
+
+
+/*
+** This routine adds datatype and collating sequence information to
+** the Table structures of all FROM-clause subqueries in a
+** SELECT statement.
+**
+** Use this routine after name resolution.
+*/
+static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){
+#ifndef SQLITE_OMIT_SUBQUERY
+  Walker w;
+  w.xSelectCallback = sqlite3SelectWalkNoop;
+  w.xSelectCallback2 = selectAddSubqueryTypeInfo;
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.pParse = pParse;
+  sqlite3WalkSelect(&w, pSelect);
+#endif
+}
+
+
+/*
+** This routine sets up a SELECT statement for processing.  The
+** following is accomplished:
+**
+**     *  VDBE Cursor numbers are assigned to all FROM-clause terms.
+**     *  Ephemeral Table objects are created for all FROM-clause subqueries.
+**     *  ON and USING clauses are shifted into WHERE statements
+**     *  Wildcards "*" and "TABLE.*" in result sets are expanded.
+**     *  Identifiers in expression are matched to tables.
+**
+** This routine acts recursively on all subqueries within the SELECT.
+*/
+SQLITE_PRIVATE void sqlite3SelectPrep(
+  Parse *pParse,         /* The parser context */
+  Select *p,             /* The SELECT statement being coded. */
+  NameContext *pOuterNC  /* Name context for container */
+){
+  assert( p!=0 || pParse->db->mallocFailed );
+  assert( pParse->db->pParse==pParse );
+  if( pParse->db->mallocFailed ) return;
+  if( p->selFlags & SF_HasTypeInfo ) return;
+  sqlite3SelectExpand(pParse, p);
+  if( pParse->nErr ) return;
+  sqlite3ResolveSelectNames(pParse, p, pOuterNC);
+  if( pParse->nErr ) return;
+  sqlite3SelectAddTypeInfo(pParse, p);
+}
+
+#if TREETRACE_ENABLED
+/*
+** Display all information about an AggInfo object
+*/
+static void printAggInfo(AggInfo *pAggInfo){
+  int ii;
+  sqlite3DebugPrintf("AggInfo %d/%p:\n",
+     pAggInfo->selId, pAggInfo);
+  for(ii=0; ii<pAggInfo->nColumn; ii++){
+    struct AggInfo_col *pCol = &pAggInfo->aCol[ii];
+    sqlite3DebugPrintf(
+       "agg-column[%d] pTab=%s iTable=%d iColumn=%d iMem=%d"
+       " iSorterColumn=%d %s\n",
+       ii, pCol->pTab ? pCol->pTab->zName : "NULL",
+       pCol->iTable, pCol->iColumn, pAggInfo->iFirstReg+ii,
+       pCol->iSorterColumn,
+       ii>=pAggInfo->nAccumulator ? "" : " Accumulator");
+    sqlite3TreeViewExpr(0, pAggInfo->aCol[ii].pCExpr, 0);
+  }
+  for(ii=0; ii<pAggInfo->nFunc; ii++){
+    sqlite3DebugPrintf("agg-func[%d]: iMem=%d\n",
+        ii, pAggInfo->iFirstReg+pAggInfo->nColumn+ii);
+    sqlite3TreeViewExpr(0, pAggInfo->aFunc[ii].pFExpr, 0);
+  }
+}
+#endif /* TREETRACE_ENABLED */
+
+/*
+** Analyze the arguments to aggregate functions.  Create new pAggInfo->aCol[]
+** entries for columns that are arguments to aggregate functions but which
+** are not otherwise used.
+**
+** The aCol[] entries in AggInfo prior to nAccumulator are columns that
+** are referenced outside of aggregate functions.  These might be columns
+** that are part of the GROUP by clause, for example.  Other database engines
+** would throw an error if there is a column reference that is not in the
+** GROUP BY clause and that is not part of an aggregate function argument.
+** But SQLite allows this.
+**
+** The aCol[] entries beginning with the aCol[nAccumulator] and following
+** are column references that are used exclusively as arguments to
+** aggregate functions.  This routine is responsible for computing
+** (or recomputing) those aCol[] entries.
+*/
+static void analyzeAggFuncArgs(
+  AggInfo *pAggInfo,
+  NameContext *pNC
+){
+  int i;
+  assert( pAggInfo!=0 );
+  assert( pAggInfo->iFirstReg==0 );
+  pNC->ncFlags |= NC_InAggFunc;
+  for(i=0; i<pAggInfo->nFunc; i++){
+    Expr *pExpr = pAggInfo->aFunc[i].pFExpr;
+    assert( pExpr->op==TK_FUNCTION || pExpr->op==TK_AGG_FUNCTION );
+    assert( ExprUseXList(pExpr) );
+    sqlite3ExprAnalyzeAggList(pNC, pExpr->x.pList);
+    if( pExpr->pLeft ){
+      assert( pExpr->pLeft->op==TK_ORDER );
+      assert( ExprUseXList(pExpr->pLeft) );
+      sqlite3ExprAnalyzeAggList(pNC, pExpr->pLeft->x.pList);
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    assert( !IsWindowFunc(pExpr) );
+    if( ExprHasProperty(pExpr, EP_WinFunc) ){
+      sqlite3ExprAnalyzeAggregates(pNC, pExpr->y.pWin->pFilter);
+    }
+#endif
+  }
+  pNC->ncFlags &= ~NC_InAggFunc;
+}
+
+/*
+** An index on expressions is being used in the inner loop of an
+** aggregate query with a GROUP BY clause.  This routine attempts
+** to adjust the AggInfo object to take advantage of index and to
+** perhaps use the index as a covering index.
+**
+*/
+static void optimizeAggregateUseOfIndexedExpr(
+  Parse *pParse,          /* Parsing context */
+  Select *pSelect,        /* The SELECT statement being processed */
+  AggInfo *pAggInfo,      /* The aggregate info */
+  NameContext *pNC        /* Name context used to resolve agg-func args */
+){
+  assert( pAggInfo->iFirstReg==0 );
+  assert( pSelect!=0 );
+  assert( pSelect->pGroupBy!=0 );
+  pAggInfo->nColumn = pAggInfo->nAccumulator;
+  if( ALWAYS(pAggInfo->nSortingColumn>0) ){
+    int mx = pSelect->pGroupBy->nExpr - 1;
+    int j, k;
+    for(j=0; j<pAggInfo->nColumn; j++){
+      k = pAggInfo->aCol[j].iSorterColumn;
+      if( k>mx ) mx = k;
+    }
+    pAggInfo->nSortingColumn = mx+1;
+  }
+  analyzeAggFuncArgs(pAggInfo, pNC);
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x20 ){
+    IndexedExpr *pIEpr;
+    TREETRACE(0x20, pParse, pSelect,
+        ("AggInfo (possibly) adjusted for Indexed Exprs\n"));
+    sqlite3TreeViewSelect(0, pSelect, 0);
+    for(pIEpr=pParse->pIdxEpr; pIEpr; pIEpr=pIEpr->pIENext){
+      printf("data-cursor=%d index={%d,%d}\n",
+          pIEpr->iDataCur, pIEpr->iIdxCur, pIEpr->iIdxCol);
+      sqlite3TreeViewExpr(0, pIEpr->pExpr, 0);
+    }
+    printAggInfo(pAggInfo);
+  }
+#else
+  UNUSED_PARAMETER(pSelect);
+  UNUSED_PARAMETER(pParse);
+#endif
+}
+
+/*
+** Walker callback for aggregateConvertIndexedExprRefToColumn().
+*/
+static int aggregateIdxEprRefToColCallback(Walker *pWalker, Expr *pExpr){
+  AggInfo *pAggInfo;
+  struct AggInfo_col *pCol;
+  UNUSED_PARAMETER(pWalker);
+  if( pExpr->pAggInfo==0 ) return WRC_Continue;
+  if( pExpr->op==TK_AGG_COLUMN ) return WRC_Continue;
+  if( pExpr->op==TK_AGG_FUNCTION ) return WRC_Continue;
+  if( pExpr->op==TK_IF_NULL_ROW ) return WRC_Continue;
+  pAggInfo = pExpr->pAggInfo;
+  if( NEVER(pExpr->iAgg>=pAggInfo->nColumn) ) return WRC_Continue;
+  assert( pExpr->iAgg>=0 );
+  pCol = &pAggInfo->aCol[pExpr->iAgg];
+  pExpr->op = TK_AGG_COLUMN;
+  pExpr->iTable = pCol->iTable;
+  pExpr->iColumn = pCol->iColumn;
+  ExprClearProperty(pExpr, EP_Skip|EP_Collate|EP_Unlikely);
+  return WRC_Prune;
+}
+
+/*
+** Convert every pAggInfo->aFunc[].pExpr such that any node within
+** those expressions that has pAppInfo set is changed into a TK_AGG_COLUMN
+** opcode.
+*/
+static void aggregateConvertIndexedExprRefToColumn(AggInfo *pAggInfo){
+  int i;
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = aggregateIdxEprRefToColCallback;
+  for(i=0; i<pAggInfo->nFunc; i++){
+    sqlite3WalkExpr(&w, pAggInfo->aFunc[i].pFExpr);
+  }
+}
+
+
+/*
+** Allocate a block of registers so that there is one register for each
+** pAggInfo->aCol[] and pAggInfo->aFunc[] entry in pAggInfo.  The first
+** register in this block is stored in pAggInfo->iFirstReg.
+**
+** This routine may only be called once for each AggInfo object.  Prior
+** to calling this routine:
+**
+**     *  The aCol[] and aFunc[] arrays may be modified
+**     *  The AggInfoColumnReg() and AggInfoFuncReg() macros may not be used
+**
+** After calling this routine:
+**
+**     *  The aCol[] and aFunc[] arrays are fixed
+**     *  The AggInfoColumnReg() and AggInfoFuncReg() macros may be used
+**
+*/
+static void assignAggregateRegisters(Parse *pParse, AggInfo *pAggInfo){
+  assert( pAggInfo!=0 );
+  assert( pAggInfo->iFirstReg==0 );
+  pAggInfo->iFirstReg = pParse->nMem + 1;
+  pParse->nMem += pAggInfo->nColumn + pAggInfo->nFunc;
+}
+
+/*
+** Reset the aggregate accumulator.
+**
+** The aggregate accumulator is a set of memory cells that hold
+** intermediate results while calculating an aggregate.  This
+** routine generates code that stores NULLs in all of those memory
+** cells.
+*/
+static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  struct AggInfo_func *pFunc;
+  int nReg = pAggInfo->nFunc + pAggInfo->nColumn;
+  assert( pAggInfo->iFirstReg>0 );
+  assert( pParse->db->pParse==pParse );
+  assert( pParse->db->mallocFailed==0 || pParse->nErr!=0 );
+  if( nReg==0 ) return;
+  if( pParse->nErr ) return;
+  sqlite3VdbeAddOp3(v, OP_Null, 0, pAggInfo->iFirstReg,
+                    pAggInfo->iFirstReg+nReg-1);
+  for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
+    if( pFunc->iDistinct>=0 ){
+      Expr *pE = pFunc->pFExpr;
+      assert( ExprUseXList(pE) );
+      if( pE->x.pList==0 || pE->x.pList->nExpr!=1 ){
+        sqlite3ErrorMsg(pParse, "DISTINCT aggregates must have exactly one "
+           "argument");
+        pFunc->iDistinct = -1;
+      }else{
+        KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pE->x.pList,0,0);
+        pFunc->iDistAddr = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+            pFunc->iDistinct, 0, 0, (char*)pKeyInfo, P4_KEYINFO);
+        ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s(DISTINCT)",
+                          pFunc->pFunc->zName));
+      }
+    }
+    if( pFunc->iOBTab>=0 ){
+      ExprList *pOBList;
+      KeyInfo *pKeyInfo;
+      int nExtra = 0;
+      assert( pFunc->pFExpr->pLeft!=0 );
+      assert( pFunc->pFExpr->pLeft->op==TK_ORDER );
+      assert( ExprUseXList(pFunc->pFExpr->pLeft) );
+      assert( pFunc->pFunc!=0 );
+      pOBList = pFunc->pFExpr->pLeft->x.pList;
+      if( !pFunc->bOBUnique ){
+        nExtra++;  /* One extra column for the OP_Sequence */
+      }
+      if( pFunc->bOBPayload ){
+        /* extra columns for the function arguments */
+        assert( ExprUseXList(pFunc->pFExpr) );
+        nExtra += pFunc->pFExpr->x.pList->nExpr;
+      }
+      if( pFunc->bUseSubtype ){
+        nExtra += pFunc->pFExpr->x.pList->nExpr;
+      }
+      pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pOBList, 0, nExtra);
+      if( !pFunc->bOBUnique && pParse->nErr==0 ){
+        pKeyInfo->nKeyField++;
+      }
+      sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+            pFunc->iOBTab, pOBList->nExpr+nExtra, 0,
+            (char*)pKeyInfo, P4_KEYINFO);
+      ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s(ORDER BY)",
+                          pFunc->pFunc->zName));
+    }
+  }
+}
+
+/*
+** Invoke the OP_AggFinalize opcode for every aggregate function
+** in the AggInfo structure.
+*/
+static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  struct AggInfo_func *pF;
+  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
+    ExprList *pList;
+    assert( ExprUseXList(pF->pFExpr) );
+    if( pParse->nErr ) return;
+    pList = pF->pFExpr->x.pList;
+    if( pF->iOBTab>=0 ){
+      /* For an ORDER BY aggregate, calls to OP_AggStep were deferred.  Inputs
+      ** were stored in emphermal table pF->iOBTab.  Here, we extract those
+      ** inputs (in ORDER BY order) and make all calls to OP_AggStep
+      ** before doing the OP_AggFinal call. */
+      int iTop;        /* Start of loop for extracting columns */
+      int nArg;        /* Number of columns to extract */
+      int nKey;        /* Key columns to be skipped */
+      int regAgg;      /* Extract into this array */
+      int j;           /* Loop counter */
+
+      assert( pF->pFunc!=0 );
+      nArg = pList->nExpr;
+      regAgg = sqlite3GetTempRange(pParse, nArg);
+
+      if( pF->bOBPayload==0 ){
+        nKey = 0;
+      }else{
+        assert( pF->pFExpr->pLeft!=0 );
+        assert( ExprUseXList(pF->pFExpr->pLeft) );
+        assert( pF->pFExpr->pLeft->x.pList!=0 );
+        nKey = pF->pFExpr->pLeft->x.pList->nExpr;
+        if( ALWAYS(!pF->bOBUnique) ) nKey++;
+      }
+      iTop = sqlite3VdbeAddOp1(v, OP_Rewind, pF->iOBTab); VdbeCoverage(v);
+      for(j=nArg-1; j>=0; j--){
+        sqlite3VdbeAddOp3(v, OP_Column, pF->iOBTab, nKey+j, regAgg+j);
+      }
+      if( pF->bUseSubtype ){
+        int regSubtype = sqlite3GetTempReg(pParse);
+        int iBaseCol = nKey + nArg + (pF->bOBPayload==0 && pF->bOBUnique==0);
+        for(j=nArg-1; j>=0; j--){
+          sqlite3VdbeAddOp3(v, OP_Column, pF->iOBTab, iBaseCol+j, regSubtype);
+          sqlite3VdbeAddOp2(v, OP_SetSubtype, regSubtype, regAgg+j);
+        }
+        sqlite3ReleaseTempReg(pParse, regSubtype);
+      }
+      sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, AggInfoFuncReg(pAggInfo,i));
+      sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
+      sqlite3VdbeChangeP5(v, (u16)nArg);
+      sqlite3VdbeAddOp2(v, OP_Next, pF->iOBTab, iTop+1); VdbeCoverage(v);
+      sqlite3VdbeJumpHere(v, iTop);
+      sqlite3ReleaseTempRange(pParse, regAgg, nArg);
+    }
+    sqlite3VdbeAddOp2(v, OP_AggFinal, AggInfoFuncReg(pAggInfo,i),
+                      pList ? pList->nExpr : 0);
+    sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
+  }
+}
+
+/*
+** Generate code that will update the accumulator memory cells for an
+** aggregate based on the current cursor position.
+**
+** If regAcc is non-zero and there are no min() or max() aggregates
+** in pAggInfo, then only populate the pAggInfo->nAccumulator accumulator
+** registers if register regAcc contains 0. The caller will take care
+** of setting and clearing regAcc.
+**
+** For an ORDER BY aggregate, the actual accumulator memory cell update
+** is deferred until after all input rows have been received, so that they
+** can be run in the requested order.  In that case, instead of invoking
+** OP_AggStep to update the accumulator, just add the arguments that would
+** have been passed into OP_AggStep into the sorting ephemeral table
+** (along with the appropriate sort key).
+*/
+static void updateAccumulator(
+  Parse *pParse,
+  int regAcc,
+  AggInfo *pAggInfo,
+  int eDistinctType
+){
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  int regHit = 0;
+  int addrHitTest = 0;
+  struct AggInfo_func *pF;
+  struct AggInfo_col *pC;
+
+  assert( pAggInfo->iFirstReg>0 );
+  if( pParse->nErr ) return;
+  pAggInfo->directMode = 1;
+  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
+    int nArg;
+    int addrNext = 0;
+    int regAgg;
+    int regAggSz = 0;
+    int regDistinct = 0;
+    ExprList *pList;
+    assert( ExprUseXList(pF->pFExpr) );
+    assert( !IsWindowFunc(pF->pFExpr) );
+    assert( pF->pFunc!=0 );
+    pList = pF->pFExpr->x.pList;
+    if( ExprHasProperty(pF->pFExpr, EP_WinFunc) ){
+      Expr *pFilter = pF->pFExpr->y.pWin->pFilter;
+      if( pAggInfo->nAccumulator
+       && (pF->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL)
+       && regAcc
+      ){
+        /* If regAcc==0, there there exists some min() or max() function
+        ** without a FILTER clause that will ensure the magnet registers
+        ** are populated. */
+        if( regHit==0 ) regHit = ++pParse->nMem;
+        /* If this is the first row of the group (regAcc contains 0), clear the
+        ** "magnet" register regHit so that the accumulator registers
+        ** are populated if the FILTER clause jumps over the the
+        ** invocation of min() or max() altogether. Or, if this is not
+        ** the first row (regAcc contains 1), set the magnet register so that
+        ** the accumulators are not populated unless the min()/max() is invoked
+        ** and indicates that they should be.  */
+        sqlite3VdbeAddOp2(v, OP_Copy, regAcc, regHit);
+      }
+      addrNext = sqlite3VdbeMakeLabel(pParse);
+      sqlite3ExprIfFalse(pParse, pFilter, addrNext, SQLITE_JUMPIFNULL);
+    }
+    if( pF->iOBTab>=0 ){
+      /* Instead of invoking AggStep, we must push the arguments that would
+      ** have been passed to AggStep onto the sorting table. */
+      int jj;                /* Registered used so far in building the record */
+      ExprList *pOBList;     /* The ORDER BY clause */
+      assert( pList!=0 );
+      nArg = pList->nExpr;
+      assert( nArg>0 );
+      assert( pF->pFExpr->pLeft!=0 );
+      assert( pF->pFExpr->pLeft->op==TK_ORDER );
+      assert( ExprUseXList(pF->pFExpr->pLeft) );
+      pOBList = pF->pFExpr->pLeft->x.pList;
+      assert( pOBList!=0 );
+      assert( pOBList->nExpr>0 );
+      regAggSz = pOBList->nExpr;
+      if( !pF->bOBUnique ){
+        regAggSz++;   /* One register for OP_Sequence */
+      }
+      if( pF->bOBPayload ){
+        regAggSz += nArg;
+      }
+      if( pF->bUseSubtype ){
+        regAggSz += nArg;
+      }
+      regAggSz++;  /* One extra register to hold result of MakeRecord */
+      regAgg = sqlite3GetTempRange(pParse, regAggSz);
+      regDistinct = regAgg;
+      sqlite3ExprCodeExprList(pParse, pOBList, regAgg, 0, SQLITE_ECEL_DUP);
+      jj = pOBList->nExpr;
+      if( !pF->bOBUnique ){
+        sqlite3VdbeAddOp2(v, OP_Sequence, pF->iOBTab, regAgg+jj);
+        jj++;
+      }
+      if( pF->bOBPayload ){
+        regDistinct = regAgg+jj;
+        sqlite3ExprCodeExprList(pParse, pList, regDistinct, 0, SQLITE_ECEL_DUP);
+        jj += nArg;
+      }
+      if( pF->bUseSubtype ){
+        int kk;
+        int regBase = pF->bOBPayload ? regDistinct : regAgg;
+        for(kk=0; kk<nArg; kk++, jj++){
+          sqlite3VdbeAddOp2(v, OP_GetSubtype, regBase+kk, regAgg+jj);
+        }
+      }
+    }else if( pList ){
+      nArg = pList->nExpr;
+      regAgg = sqlite3GetTempRange(pParse, nArg);
+      regDistinct = regAgg;
+      sqlite3ExprCodeExprList(pParse, pList, regAgg, 0, SQLITE_ECEL_DUP);
+    }else{
+      nArg = 0;
+      regAgg = 0;
+    }
+    if( pF->iDistinct>=0 && pList ){
+      if( addrNext==0 ){
+        addrNext = sqlite3VdbeMakeLabel(pParse);
+      }
+      pF->iDistinct = codeDistinct(pParse, eDistinctType,
+          pF->iDistinct, addrNext, pList, regDistinct);
+    }
+    if( pF->iOBTab>=0 ){
+      /* Insert a new record into the ORDER BY table */
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regAgg, regAggSz-1,
+                        regAgg+regAggSz-1);
+      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pF->iOBTab, regAgg+regAggSz-1,
+                           regAgg, regAggSz-1);
+      sqlite3ReleaseTempRange(pParse, regAgg, regAggSz);
+    }else{
+      /* Invoke the AggStep function */
+      if( pF->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){
+        CollSeq *pColl = 0;
+        struct ExprList_item *pItem;
+        int j;
+        assert( pList!=0 );  /* pList!=0 if pF->pFunc has NEEDCOLL */
+        for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
+          pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
+        }
+        if( !pColl ){
+          pColl = pParse->db->pDfltColl;
+        }
+        if( regHit==0 && pAggInfo->nAccumulator ) regHit = ++pParse->nMem;
+        sqlite3VdbeAddOp4(v, OP_CollSeq, regHit, 0, 0,
+                         (char *)pColl, P4_COLLSEQ);
+      }
+      sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, AggInfoFuncReg(pAggInfo,i));
+      sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
+      sqlite3VdbeChangeP5(v, (u16)nArg);
+      sqlite3ReleaseTempRange(pParse, regAgg, nArg);
+    }
+    if( addrNext ){
+      sqlite3VdbeResolveLabel(v, addrNext);
+    }
+    if( pParse->nErr ) return;
+  }
+  if( regHit==0 && pAggInfo->nAccumulator ){
+    regHit = regAcc;
+  }
+  if( regHit ){
+    addrHitTest = sqlite3VdbeAddOp1(v, OP_If, regHit); VdbeCoverage(v);
+  }
+  for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
+    sqlite3ExprCode(pParse, pC->pCExpr, AggInfoColumnReg(pAggInfo,i));
+    if( pParse->nErr ) return;
+  }
+
+  pAggInfo->directMode = 0;
+  if( addrHitTest ){
+    sqlite3VdbeJumpHereOrPopInst(v, addrHitTest);
+  }
+}
+
+/*
+** Add a single OP_Explain instruction to the VDBE to explain a simple
+** count(*) query ("SELECT count(*) FROM pTab").
+*/
+#ifndef SQLITE_OMIT_EXPLAIN
+static void explainSimpleCount(
+  Parse *pParse,                  /* Parse context */
+  Table *pTab,                    /* Table being queried */
+  Index *pIdx                     /* Index used to optimize scan, or NULL */
+){
+  if( pParse->explain==2 ){
+    int bCover = (pIdx!=0 && (HasRowid(pTab) || !IsPrimaryKeyIndex(pIdx)));
+    sqlite3VdbeExplain(pParse, 0, "SCAN %s%s%s",
+        pTab->zName,
+        bCover ? " USING COVERING INDEX " : "",
+        bCover ? pIdx->zName : ""
+    );
+  }
+}
+#else
+# define explainSimpleCount(a,b,c)
+#endif
+
+/*
+** sqlite3WalkExpr() callback used by havingToWhere().
+**
+** If the node passed to the callback is a TK_AND node, return
+** WRC_Continue to tell sqlite3WalkExpr() to iterate through child nodes.
+**
+** Otherwise, return WRC_Prune. In this case, also check if the
+** sub-expression matches the criteria for being moved to the WHERE
+** clause. If so, add it to the WHERE clause and replace the sub-expression
+** within the HAVING expression with a constant "1".
+*/
+static int havingToWhereExprCb(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op!=TK_AND ){
+    Select *pS = pWalker->u.pSelect;
+    /* This routine is called before the HAVING clause of the current
+    ** SELECT is analyzed for aggregates. So if pExpr->pAggInfo is set
+    ** here, it indicates that the expression is a correlated reference to a
+    ** column from an outer aggregate query, or an aggregate function that
+    ** belongs to an outer query. Do not move the expression to the WHERE
+    ** clause in this obscure case, as doing so may corrupt the outer Select
+    ** statements AggInfo structure.  */
+    if( sqlite3ExprIsConstantOrGroupBy(pWalker->pParse, pExpr, pS->pGroupBy)
+     && ExprAlwaysFalse(pExpr)==0
+     && pExpr->pAggInfo==0
+    ){
+      sqlite3 *db = pWalker->pParse->db;
+      Expr *pNew = sqlite3Expr(db, TK_INTEGER, "1");
+      if( pNew ){
+        Expr *pWhere = pS->pWhere;
+        SWAP(Expr, *pNew, *pExpr);
+        pNew = sqlite3ExprAnd(pWalker->pParse, pWhere, pNew);
+        pS->pWhere = pNew;
+        pWalker->eCode = 1;
+      }
+    }
+    return WRC_Prune;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Transfer eligible terms from the HAVING clause of a query, which is
+** processed after grouping, to the WHERE clause, which is processed before
+** grouping. For example, the query:
+**
+**   SELECT * FROM <tables> WHERE a=? GROUP BY b HAVING b=? AND c=?
+**
+** can be rewritten as:
+**
+**   SELECT * FROM <tables> WHERE a=? AND b=? GROUP BY b HAVING c=?
+**
+** A term of the HAVING expression is eligible for transfer if it consists
+** entirely of constants and expressions that are also GROUP BY terms that
+** use the "BINARY" collation sequence.
+*/
+static void havingToWhere(Parse *pParse, Select *p){
+  Walker sWalker;
+  memset(&sWalker, 0, sizeof(sWalker));
+  sWalker.pParse = pParse;
+  sWalker.xExprCallback = havingToWhereExprCb;
+  sWalker.u.pSelect = p;
+  sqlite3WalkExpr(&sWalker, p->pHaving);
+#if TREETRACE_ENABLED
+  if( sWalker.eCode && (sqlite3TreeTrace & 0x100)!=0 ){
+    TREETRACE(0x100,pParse,p,("Move HAVING terms into WHERE:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+}
+
+/*
+** Check to see if the pThis entry of pTabList is a self-join of another view.
+** Search FROM-clause entries in the range of iFirst..iEnd, including iFirst
+** but stopping before iEnd.
+**
+** If pThis is a self-join, then return the SrcItem for the first other
+** instance of that view found.  If pThis is not a self-join then return 0.
+*/
+static SrcItem *isSelfJoinView(
+  SrcList *pTabList,           /* Search for self-joins in this FROM clause */
+  SrcItem *pThis,              /* Search for prior reference to this subquery */
+  int iFirst, int iEnd        /* Range of FROM-clause entries to search. */
+){
+  SrcItem *pItem;
+  Select *pSel;
+  assert( pThis->fg.isSubquery );
+  pSel = pThis->u4.pSubq->pSelect;
+  assert( pSel!=0 );
+  if( pSel->selFlags & SF_PushDown ) return 0;
+  while( iFirst<iEnd ){
+    Select *pS1;
+    pItem = &pTabList->a[iFirst++];
+    if( !pItem->fg.isSubquery ) continue;
+    if( pItem->fg.viaCoroutine ) continue;
+    if( pItem->zName==0 ) continue;
+    assert( pItem->pSTab!=0 );
+    assert( pThis->pSTab!=0 );
+    if( pItem->pSTab->pSchema!=pThis->pSTab->pSchema ) continue;
+    if( sqlite3_stricmp(pItem->zName, pThis->zName)!=0 ) continue;
+    pS1 = pItem->u4.pSubq->pSelect;
+    if( pItem->pSTab->pSchema==0 && pSel->selId!=pS1->selId ){
+      /* The query flattener left two different CTE tables with identical
+      ** names in the same FROM clause. */
+      continue;
+    }
+    if( pS1->selFlags & SF_PushDown ){
+      /* The view was modified by some other optimization such as
+      ** pushDownWhereTerms() */
+      continue;
+    }
+    return pItem;
+  }
+  return 0;
+}
+
+/*
+** Deallocate a single AggInfo object
+*/
+static void agginfoFree(sqlite3 *db, void *pArg){
+  AggInfo *p = (AggInfo*)pArg;
+  sqlite3DbFree(db, p->aCol);
+  sqlite3DbFree(db, p->aFunc);
+  sqlite3DbFreeNN(db, p);
+}
+
+/*
+** Attempt to transform a query of the form
+**
+**    SELECT count(*) FROM (SELECT x FROM t1 UNION ALL SELECT y FROM t2)
+**
+** Into this:
+**
+**    SELECT (SELECT count(*) FROM t1)+(SELECT count(*) FROM t2)
+**
+** The transformation only works if all of the following are true:
+**
+**   *  The subquery is a UNION ALL of two or more terms
+**   *  The subquery does not have a LIMIT clause
+**   *  There is no WHERE or GROUP BY or HAVING clauses on the subqueries
+**   *  The outer query is a simple count(*) with no WHERE clause or other
+**      extraneous syntax.
+**   *  None of the subqueries are DISTINCT (forumpost/a860f5fb2e 2025-03-10)
+**
+** Return TRUE if the optimization is undertaken.
+*/
+static int countOfViewOptimization(Parse *pParse, Select *p){
+  Select *pSub, *pPrior;
+  Expr *pExpr;
+  Expr *pCount;
+  sqlite3 *db;
+  SrcItem *pFrom;
+  if( (p->selFlags & SF_Aggregate)==0 ) return 0;   /* This is an aggregate */
+  if( p->pEList->nExpr!=1 ) return 0;               /* Single result column */
+  if( p->pWhere ) return 0;
+  if( p->pHaving ) return 0;
+  if( p->pGroupBy ) return 0;
+  if( p->pOrderBy ) return 0;
+  pExpr = p->pEList->a[0].pExpr;
+  if( pExpr->op!=TK_AGG_FUNCTION ) return 0;        /* Result is an aggregate */
+  assert( ExprUseUToken(pExpr) );
+  if( sqlite3_stricmp(pExpr->u.zToken,"count") ) return 0;  /* Is count() */
+  assert( ExprUseXList(pExpr) );
+  if( pExpr->x.pList!=0 ) return 0;                 /* Must be count(*) */
+  if( p->pSrc->nSrc!=1 ) return 0;                  /* One table in FROM  */
+  if( ExprHasProperty(pExpr, EP_WinFunc) ) return 0;/* Not a window function */
+  pFrom = p->pSrc->a;
+  if( pFrom->fg.isSubquery==0 ) return 0;    /* FROM is a subquery */
+  pSub = pFrom->u4.pSubq->pSelect;
+  if( pSub->pPrior==0 ) return 0;                   /* Must be a compound */
+  if( pSub->selFlags & SF_CopyCte ) return 0;       /* Not a CTE */
+  do{
+    if( pSub->op!=TK_ALL && pSub->pPrior ) return 0;  /* Must be UNION ALL */
+    if( pSub->pWhere ) return 0;                      /* No WHERE clause */
+    if( pSub->pLimit ) return 0;                      /* No LIMIT clause */
+    if( pSub->selFlags & (SF_Aggregate|SF_Distinct) ){
+       testcase( pSub->selFlags & SF_Aggregate );
+       testcase( pSub->selFlags & SF_Distinct );
+       return 0;     /* Not an aggregate nor DISTINCT */
+    }
+    assert( pSub->pHaving==0 );  /* Due to the previous */
+    pSub = pSub->pPrior;                              /* Repeat over compound */
+  }while( pSub );
+
+  /* If we reach this point then it is OK to perform the transformation */
+
+  db = pParse->db;
+  pCount = pExpr;
+  pExpr = 0;
+  pSub = sqlite3SubqueryDetach(db, pFrom);
+  sqlite3SrcListDelete(db, p->pSrc);
+  p->pSrc = sqlite3DbMallocZero(pParse->db, sizeof(*p->pSrc));
+  while( pSub ){
+    Expr *pTerm;
+    pPrior = pSub->pPrior;
+    pSub->pPrior = 0;
+    pSub->pNext = 0;
+    pSub->selFlags |= SF_Aggregate;
+    pSub->selFlags &= ~SF_Compound;
+    pSub->nSelectRow = 0;
+    sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric, pSub->pEList);
+    pTerm = pPrior ? sqlite3ExprDup(db, pCount, 0) : pCount;
+    pSub->pEList = sqlite3ExprListAppend(pParse, 0, pTerm);
+    pTerm = sqlite3PExpr(pParse, TK_SELECT, 0, 0);
+    sqlite3PExprAddSelect(pParse, pTerm, pSub);
+    if( pExpr==0 ){
+      pExpr = pTerm;
+    }else{
+      pExpr = sqlite3PExpr(pParse, TK_PLUS, pTerm, pExpr);
+    }
+    pSub = pPrior;
+  }
+  p->pEList->a[0].pExpr = pExpr;
+  p->selFlags &= ~SF_Aggregate;
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x200 ){
+    TREETRACE(0x200,pParse,p,("After count-of-view optimization:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+  return 1;
+}
+
+/*
+** If any term of pSrc, or any SF_NestedFrom sub-query, is not the same
+** as pSrcItem but has the same alias as p0, then return true.
+** Otherwise return false.
+*/
+static int sameSrcAlias(SrcItem *p0, SrcList *pSrc){
+  int i;
+  for(i=0; i<pSrc->nSrc; i++){
+    SrcItem *p1 = &pSrc->a[i];
+    if( p1==p0 ) continue;
+    if( p0->pSTab==p1->pSTab && 0==sqlite3_stricmp(p0->zAlias, p1->zAlias) ){
+      return 1;
+    }
+    if( p1->fg.isSubquery
+     && (p1->u4.pSubq->pSelect->selFlags & SF_NestedFrom)!=0
+     && sameSrcAlias(p0, p1->u4.pSubq->pSelect->pSrc)
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Return TRUE (non-zero) if the i-th entry in the pTabList SrcList can
+** be implemented as a co-routine.  The i-th entry is guaranteed to be
+** a subquery.
+**
+** The subquery is implemented as a co-routine if all of the following are
+** true:
+**
+**    (1)  The subquery will likely be implemented in the outer loop of
+**         the query.  This will be the case if any one of the following
+**         conditions hold:
+**         (a)  The subquery is the only term in the FROM clause
+**         (b)  The subquery is the left-most term and a CROSS JOIN or similar
+**              requires it to be the outer loop
+**         (c)  All of the following are true:
+**                (i) The subquery is the left-most subquery in the FROM clause
+**               (ii) There is nothing that would prevent the subquery from
+**                    being used as the outer loop if the sqlite3WhereBegin()
+**                    routine nominates it to that position.
+**              (iii) The query is not a UPDATE ... FROM
+**    (2)  The subquery is not a CTE that should be materialized because
+**         (a) the AS MATERIALIZED keyword is used, or
+**         (b) the CTE is used multiple times and does not have the
+**             NOT MATERIALIZED keyword
+**    (3)  The subquery is not part of a left operand for a RIGHT JOIN
+**    (4)  The SQLITE_Coroutine optimization disable flag is not set
+**    (5)  The subquery is not self-joined
+*/
+static int fromClauseTermCanBeCoroutine(
+  Parse *pParse,          /* Parsing context */
+  SrcList *pTabList,      /* FROM clause */
+  int i,                  /* Which term of the FROM clause holds the subquery */
+  int selFlags            /* Flags on the SELECT statement */
+){
+  SrcItem *pItem = &pTabList->a[i];
+  if( pItem->fg.isCte ){
+    const CteUse *pCteUse = pItem->u2.pCteUse;
+    if( pCteUse->eM10d==M10d_Yes ) return 0;                          /* (2a) */
+    if( pCteUse->nUse>=2 && pCteUse->eM10d!=M10d_No ) return 0;       /* (2b) */
+  }
+  if( pTabList->a[0].fg.jointype & JT_LTORJ ) return 0;               /* (3)  */
+  if( OptimizationDisabled(pParse->db, SQLITE_Coroutines) ) return 0; /* (4)  */
+  if( isSelfJoinView(pTabList, pItem, i+1, pTabList->nSrc)!=0 ){
+    return 0;                                                          /* (5) */
+  }
+  if( i==0 ){
+    if( pTabList->nSrc==1 ) return 1;                             /* (1a) */
+    if( pTabList->a[1].fg.jointype & JT_CROSS ) return 1;         /* (1b) */
+    if( selFlags & SF_UpdateFrom )              return 0;         /* (1c-iii) */
+    return 1;
+  }
+  if( selFlags & SF_UpdateFrom ) return 0;                        /* (1c-iii) */
+  while( 1 /*exit-by-break*/ ){
+    if( pItem->fg.jointype & (JT_OUTER|JT_CROSS)  ) return 0;     /* (1c-ii) */
+    if( i==0 ) break;
+    i--;
+    pItem--;
+    if( pItem->fg.isSubquery ) return 0;                          /* (1c-i) */
+  }
+  return 1;
+}
+
+/*
+** Generate byte-code for the SELECT statement given in the p argument.
+**
+** The results are returned according to the SelectDest structure.
+** See comments in sqliteInt.h for further information.
+**
+** This routine returns the number of errors.  If any errors are
+** encountered, then an appropriate error message is left in
+** pParse->zErrMsg.
+**
+** This routine does NOT free the Select structure passed in.  The
+** calling function needs to do that.
+**
+** This is a long function.  The following is an outline of the processing
+** steps, with tags referencing various milestones:
+**
+**  *  Resolve names and similar preparation                tag-select-0100
+**  *  Scan of the FROM clause                              tag-select-0200
+**      +  OUTER JOIN strength reduction                      tag-select-0220
+**      +  Sub-query ORDER BY removal                         tag-select-0230
+**      +  Query flattening                                   tag-select-0240
+**  *  Separate subroutine for compound-SELECT              tag-select-0300
+**  *  WHERE-clause constant propagation                    tag-select-0330
+**  *  Count()-of-VIEW optimization                         tag-select-0350
+**  *  Scan of the FROM clause again                        tag-select-0400
+**      +  Authorize unreferenced tables                      tag-select-0410
+**      +  Predicate push-down optimization                   tag-select-0420
+**      +  Omit unused subquery columns optimization          tag-select-0440
+**      +  Generate code to implement subqueries              tag-select-0480
+**         -  Co-routines                                       tag-select-0482
+**         -  Reuse previously computed CTE                     tag-select-0484
+**         -  REuse previously computed VIEW                    tag-select-0486
+**         -  Materialize a VIEW or CTE                         tag-select-0488
+**  *  DISTINCT ORDER BY -> GROUP BY optimization           tag-select-0500
+**  *  Set up for ORDER BY                                  tag-select-0600
+**  *  Create output table                                  tag-select-0630
+**  *  Prepare registers for LIMIT                          tag-select-0650
+**  *  Setup for DISTINCT                                   tag-select-0680
+**  *  Generate code for non-aggregate and non-GROUP BY     tag-select-0700
+**  *  Generate code for aggregate and/or GROUP BY          tag-select-0800
+**      +  GROUP BY queries                                   tag-select-0810
+**      +  non-GROUP BY queries                               tag-select-0820
+**         -  Special case of count() w/o GROUP BY              tag-select-0821
+**         -  General case of non-GROUP BY aggregates           tag-select-0822
+**  *  Sort results, as needed                              tag-select-0900
+**  *  Internal self-checks                                 tag-select-1000
+*/
+SQLITE_PRIVATE int sqlite3Select(
+  Parse *pParse,         /* The parser context */
+  Select *p,             /* The SELECT statement being coded. */
+  SelectDest *pDest      /* What to do with the query results */
+){
+  int i, j;              /* Loop counters */
+  WhereInfo *pWInfo;     /* Return from sqlite3WhereBegin() */
+  Vdbe *v;               /* The virtual machine under construction */
+  int isAgg;             /* True for select lists like "count(*)" */
+  ExprList *pEList = 0;  /* List of columns to extract. */
+  SrcList *pTabList;     /* List of tables to select from */
+  Expr *pWhere;          /* The WHERE clause.  May be NULL */
+  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
+  Expr *pHaving;         /* The HAVING clause.  May be NULL */
+  AggInfo *pAggInfo = 0; /* Aggregate information */
+  int rc = 1;            /* Value to return from this function */
+  DistinctCtx sDistinct; /* Info on how to code the DISTINCT keyword */
+  SortCtx sSort;         /* Info on how to code the ORDER BY clause */
+  int iEnd;              /* Address of the end of the query */
+  sqlite3 *db;           /* The database connection */
+  ExprList *pMinMaxOrderBy = 0;  /* Added ORDER BY for min/max queries */
+  u8 minMaxFlag;                 /* Flag for min/max queries */
+
+  db = pParse->db;
+  assert( pParse==db->pParse );
+  v = sqlite3GetVdbe(pParse);
+  if( p==0 || pParse->nErr ){
+    return 1;
+  }
+  assert( db->mallocFailed==0 );
+  if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
+#if TREETRACE_ENABLED
+  TREETRACE(0x1,pParse,p, ("begin processing:\n", pParse->addrExplain));
+  if( sqlite3TreeTrace & 0x10000 ){
+    if( (sqlite3TreeTrace & 0x10001)==0x10000 ){
+      sqlite3TreeViewLine(0, "In sqlite3Select() at %s:%d",
+                           __FILE__, __LINE__);
+    }
+    sqlite3ShowSelect(p);
+  }
+#endif
+
+  /* tag-select-0100 */
+  assert( p->pOrderBy==0 || pDest->eDest!=SRT_DistFifo );
+  assert( p->pOrderBy==0 || pDest->eDest!=SRT_Fifo );
+  assert( p->pOrderBy==0 || pDest->eDest!=SRT_DistQueue );
+  assert( p->pOrderBy==0 || pDest->eDest!=SRT_Queue );
+  if( IgnorableDistinct(pDest) ){
+    assert(pDest->eDest==SRT_Exists     || pDest->eDest==SRT_Union ||
+           pDest->eDest==SRT_Except     || pDest->eDest==SRT_Discard ||
+           pDest->eDest==SRT_DistQueue  || pDest->eDest==SRT_DistFifo );
+    /* All of these destinations are also able to ignore the ORDER BY clause */
+    if( p->pOrderBy ){
+#if TREETRACE_ENABLED
+      TREETRACE(0x800,pParse,p, ("dropping superfluous ORDER BY:\n"));
+      if( sqlite3TreeTrace & 0x800 ){
+        sqlite3TreeViewExprList(0, p->pOrderBy, 0, "ORDERBY");
+      }
+#endif
+      sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric,
+                              p->pOrderBy);
+      testcase( pParse->earlyCleanup );
+      p->pOrderBy = 0;
+    }
+    p->selFlags &= ~SF_Distinct;
+    p->selFlags |= SF_NoopOrderBy;
+  }
+  sqlite3SelectPrep(pParse, p, 0);
+  if( pParse->nErr ){
+    goto select_end;
+  }
+  assert( db->mallocFailed==0 );
+  assert( p->pEList!=0 );
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x10 ){
+    TREETRACE(0x10,pParse,p, ("after name resolution:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+
+  /* If the SF_UFSrcCheck flag is set, then this function is being called
+  ** as part of populating the temp table for an UPDATE...FROM statement.
+  ** In this case, it is an error if the target object (pSrc->a[0]) name
+  ** or alias is duplicated within FROM clause (pSrc->a[1..n]).
+  **
+  ** Postgres disallows this case too. The reason is that some other
+  ** systems handle this case differently, and not all the same way,
+  ** which is just confusing. To avoid this, we follow PG's lead and
+  ** disallow it altogether.  */
+  if( p->selFlags & SF_UFSrcCheck ){
+    SrcItem *p0 = &p->pSrc->a[0];
+    if( sameSrcAlias(p0, p->pSrc) ){
+      sqlite3ErrorMsg(pParse,
+          "target object/alias may not appear in FROM clause: %s",
+          p0->zAlias ? p0->zAlias : p0->pSTab->zName
+      );
+      goto select_end;
+    }
+
+    /* Clear the SF_UFSrcCheck flag. The check has already been performed,
+    ** and leaving this flag set can cause errors if a compound sub-query
+    ** in p->pSrc is flattened into this query and this function called
+    ** again as part of compound SELECT processing.  */
+    p->selFlags &= ~SF_UFSrcCheck;
+  }
+
+  if( pDest->eDest==SRT_Output ){
+    sqlite3GenerateColumnNames(pParse, p);
+  }
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( sqlite3WindowRewrite(pParse, p) ){
+    assert( pParse->nErr );
+    goto select_end;
+  }
+#if TREETRACE_ENABLED
+  if( p->pWin && (sqlite3TreeTrace & 0x40)!=0 ){
+    TREETRACE(0x40,pParse,p, ("after window rewrite:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+  pTabList = p->pSrc;
+  isAgg = (p->selFlags & SF_Aggregate)!=0;
+  memset(&sSort, 0, sizeof(sSort));
+  sSort.pOrderBy = p->pOrderBy;
+
+  /* Try to do various optimizations (flattening subqueries, and strength
+  ** reduction of join operators) in the FROM clause up into the main query
+  ** tag-select-0200
+  */
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+  for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
+    SrcItem *pItem = &pTabList->a[i];
+    Select *pSub = pItem->fg.isSubquery ? pItem->u4.pSubq->pSelect : 0;
+    Table *pTab = pItem->pSTab;
+
+    /* The expander should have already created transient Table objects
+    ** even for FROM clause elements such as subqueries that do not correspond
+    ** to a real table */
+    assert( pTab!=0 );
+
+    /* Try to simplify joins:
+    **
+    **      LEFT JOIN  ->  JOIN
+    **     RIGHT JOIN  ->  JOIN
+    **      FULL JOIN  ->  RIGHT JOIN
+    **
+    ** If terms of the i-th table are used in the WHERE clause in such a
+    ** way that the i-th table cannot be the NULL row of a join, then
+    ** perform the appropriate simplification. This is called
+    ** "OUTER JOIN strength reduction" in the SQLite documentation.
+    ** tag-select-0220
+    */
+    if( (pItem->fg.jointype & (JT_LEFT|JT_LTORJ))!=0
+     && sqlite3ExprImpliesNonNullRow(p->pWhere, pItem->iCursor,
+                                     pItem->fg.jointype & JT_LTORJ)
+     && OptimizationEnabled(db, SQLITE_SimplifyJoin)
+    ){
+      if( pItem->fg.jointype & JT_LEFT ){
+        if( pItem->fg.jointype & JT_RIGHT ){
+          TREETRACE(0x1000,pParse,p,
+                    ("FULL-JOIN simplifies to RIGHT-JOIN on term %d\n",i));
+          pItem->fg.jointype &= ~JT_LEFT;
+        }else{
+          TREETRACE(0x1000,pParse,p,
+                    ("LEFT-JOIN simplifies to JOIN on term %d\n",i));
+          pItem->fg.jointype &= ~(JT_LEFT|JT_OUTER);
+          unsetJoinExpr(p->pWhere, pItem->iCursor, 0);
+        }
+      }
+      if( pItem->fg.jointype & JT_LTORJ ){
+        for(j=i+1; j<pTabList->nSrc; j++){
+          SrcItem *pI2 = &pTabList->a[j];
+          if( pI2->fg.jointype & JT_RIGHT ){
+            if( pI2->fg.jointype & JT_LEFT ){
+              TREETRACE(0x1000,pParse,p,
+                        ("FULL-JOIN simplifies to LEFT-JOIN on term %d\n",j));
+              pI2->fg.jointype &= ~JT_RIGHT;
+            }else{
+              TREETRACE(0x1000,pParse,p,
+                        ("RIGHT-JOIN simplifies to JOIN on term %d\n",j));
+              pI2->fg.jointype &= ~(JT_RIGHT|JT_OUTER);
+              unsetJoinExpr(p->pWhere, pI2->iCursor, 1);
+            }
+          }
+        }
+        for(j=pTabList->nSrc-1; j>=0; j--){
+          pTabList->a[j].fg.jointype &= ~JT_LTORJ;
+          if( pTabList->a[j].fg.jointype & JT_RIGHT ) break;
+        }
+      }
+    }
+
+    /* No further action if this term of the FROM clause is not a subquery */
+    if( pSub==0 ) continue;
+
+    /* Catch mismatch in the declared columns of a view and the number of
+    ** columns in the SELECT on the RHS */
+    if( pTab->nCol!=pSub->pEList->nExpr ){
+      sqlite3ErrorMsg(pParse, "expected %d columns for '%s' but got %d",
+                      pTab->nCol, pTab->zName, pSub->pEList->nExpr);
+      goto select_end;
+    }
+
+    /* Do not attempt the usual optimizations (flattening and ORDER BY
+    ** elimination) on a MATERIALIZED common table expression because
+    ** a MATERIALIZED common table expression is an optimization fence.
+    */
+    if( pItem->fg.isCte && pItem->u2.pCteUse->eM10d==M10d_Yes ){
+      continue;
+    }
+
+    /* Do not try to flatten an aggregate subquery.
+    **
+    ** Flattening an aggregate subquery is only possible if the outer query
+    ** is not a join.  But if the outer query is not a join, then the subquery
+    ** will be implemented as a co-routine and there is no advantage to
+    ** flattening in that case.
+    */
+    if( (pSub->selFlags & SF_Aggregate)!=0 ) continue;
+    assert( pSub->pGroupBy==0 );
+
+    /* tag-select-0230:
+    ** If a FROM-clause subquery has an ORDER BY clause that is not
+    ** really doing anything, then delete it now so that it does not
+    ** interfere with query flattening.  See the discussion at
+    ** https://sqlite.org/forum/forumpost/2d76f2bcf65d256a
+    **
+    ** Beware of these cases where the ORDER BY clause may not be safely
+    ** omitted:
+    **
+    **    (1)   There is also a LIMIT clause
+    **    (2)   The subquery was added to help with window-function
+    **          processing
+    **    (3)   The subquery is in the FROM clause of an UPDATE
+    **    (4)   The outer query uses an aggregate function other than
+    **          the built-in count(), min(), or max().
+    **    (5)   The ORDER BY isn't going to accomplish anything because
+    **          one of:
+    **            (a)  The outer query has a different ORDER BY clause
+    **            (b)  The subquery is part of a join
+    **          See forum post 062d576715d277c8
+    **    (6)   The subquery is not a recursive CTE.  ORDER BY has a different
+    **          meaning for recursive CTEs and this optimization does not
+    **          apply.
+    **
+    ** Also retain the ORDER BY if the OmitOrderBy optimization is disabled.
+    */
+    if( pSub->pOrderBy!=0
+     && (p->pOrderBy!=0 || pTabList->nSrc>1)      /* Condition (5) */
+     && pSub->pLimit==0                           /* Condition (1) */
+     && (pSub->selFlags & (SF_OrderByReqd|SF_Recursive))==0  /* (2) and (6) */
+     && (p->selFlags & SF_OrderByReqd)==0         /* Condition (3) and (4) */
+     && OptimizationEnabled(db, SQLITE_OmitOrderBy)
+    ){
+      TREETRACE(0x800,pParse,p,
+                ("omit superfluous ORDER BY on %r FROM-clause subquery\n",i+1));
+      sqlite3ParserAddCleanup(pParse, sqlite3ExprListDeleteGeneric,
+                              pSub->pOrderBy);
+      pSub->pOrderBy = 0;
+    }
+
+    /* If the outer query contains a "complex" result set (that is,
+    ** if the result set of the outer query uses functions or subqueries)
+    ** and if the subquery contains an ORDER BY clause and if
+    ** it will be implemented as a co-routine, then do not flatten.  This
+    ** restriction allows SQL constructs like this:
+    **
+    **  SELECT expensive_function(x)
+    **    FROM (SELECT x FROM tab ORDER BY y LIMIT 10);
+    **
+    ** The expensive_function() is only computed on the 10 rows that
+    ** are output, rather than every row of the table.
+    **
+    ** The requirement that the outer query have a complex result set
+    ** means that flattening does occur on simpler SQL constraints without
+    ** the expensive_function() like:
+    **
+    **  SELECT x FROM (SELECT x FROM tab ORDER BY y LIMIT 10);
+    */
+    if( pSub->pOrderBy!=0
+     && i==0
+     && (p->selFlags & SF_ComplexResult)!=0
+     && (pTabList->nSrc==1
+         || (pTabList->a[1].fg.jointype&(JT_OUTER|JT_CROSS))!=0)
+    ){
+      continue;
+    }
+
+    /* tag-select-0240 */
+    if( flattenSubquery(pParse, p, i, isAgg) ){
+      if( pParse->nErr ) goto select_end;
+      /* This subquery can be absorbed into its parent. */
+      i = -1;
+    }
+    pTabList = p->pSrc;
+    if( db->mallocFailed ) goto select_end;
+    if( !IgnorableOrderby(pDest) ){
+      sSort.pOrderBy = p->pOrderBy;
+    }
+  }
+#endif
+
+#ifndef SQLITE_OMIT_COMPOUND_SELECT
+  /* Handle compound SELECT statements using the separate multiSelect()
+  ** procedure.  tag-select-0300
+  */
+  if( p->pPrior ){
+    rc = multiSelect(pParse, p, pDest);
+#if TREETRACE_ENABLED
+    TREETRACE(0x400,pParse,p,("end compound-select processing\n"));
+    if( (sqlite3TreeTrace & 0x400)!=0 && ExplainQueryPlanParent(pParse)==0 ){
+      sqlite3TreeViewSelect(0, p, 0);
+    }
+#endif
+    if( p->pNext==0 ) ExplainQueryPlanPop(pParse);
+    return rc;
+  }
+#endif
+
+  /* Do the WHERE-clause constant propagation optimization if this is
+  ** a join.  No need to spend time on this operation for non-join queries
+  ** as the equivalent optimization will be handled by query planner in
+  ** sqlite3WhereBegin().  tag-select-0330
+  */
+  if( p->pWhere!=0
+   && p->pWhere->op==TK_AND
+   && OptimizationEnabled(db, SQLITE_PropagateConst)
+   && propagateConstants(pParse, p)
+  ){
+#if TREETRACE_ENABLED
+    if( sqlite3TreeTrace & 0x2000 ){
+      TREETRACE(0x2000,pParse,p,("After constant propagation:\n"));
+      sqlite3TreeViewSelect(0, p, 0);
+    }
+#endif
+  }else{
+    TREETRACE(0x2000,pParse,p,("Constant propagation not helpful\n"));
+  }
+
+  /* tag-select-0350 */
+  if( OptimizationEnabled(db, SQLITE_QueryFlattener|SQLITE_CountOfView)
+   && countOfViewOptimization(pParse, p)
+  ){
+    if( db->mallocFailed ) goto select_end;
+    pTabList = p->pSrc;
+  }
+
+  /* Loop over all terms in the FROM clause and do two things for each term:
+  **
+  **   (1) Authorize unreferenced tables
+  **   (2) Generate code for all sub-queries
+  **
+  ** tag-select-0400
+  */
+  for(i=0; i<pTabList->nSrc; i++){
+    SrcItem *pItem = &pTabList->a[i];
+    SrcItem *pPrior;
+    SelectDest dest;
+    Subquery *pSubq;
+    Select *pSub;
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+    const char *zSavedAuthContext;
+#endif
+
+    /* Authorized unreferenced tables.  tag-select-0410
+    **
+    ** Issue SQLITE_READ authorizations with a fake column name for any
+    ** tables that are referenced but from which no values are extracted.
+    ** Examples of where these kinds of null SQLITE_READ authorizations
+    ** would occur:
+    **
+    **     SELECT count(*) FROM t1;   -- SQLITE_READ t1.""
+    **     SELECT t1.* FROM t1, t2;   -- SQLITE_READ t2.""
+    **
+    ** The fake column name is an empty string.  It is possible for a table to
+    ** have a column named by the empty string, in which case there is no way to
+    ** distinguish between an unreferenced table and an actual reference to the
+    ** "" column. The original design was for the fake column name to be a NULL,
+    ** which would be unambiguous.  But legacy authorization callbacks might
+    ** assume the column name is non-NULL and segfault.  The use of an empty
+    ** string for the fake column name seems safer.
+    */
+    if( pItem->colUsed==0 && pItem->zName!=0 ){
+      const char *zDb;
+      if( pItem->fg.fixedSchema ){
+        int iDb = sqlite3SchemaToIndex(pParse->db, pItem->u4.pSchema);
+        zDb = db->aDb[iDb].zDbSName;
+      }else if( pItem->fg.isSubquery ){
+        zDb = 0;
+      }else{
+        zDb = pItem->u4.zDatabase;
+      }
+      sqlite3AuthCheck(pParse, SQLITE_READ, pItem->zName, "", zDb);
+    }
+
+#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
+    /* Generate code for all sub-queries in the FROM clause
+    */
+    if( pItem->fg.isSubquery==0 ) continue;
+    pSubq = pItem->u4.pSubq;
+    assert( pSubq!=0 );
+    pSub = pSubq->pSelect;
+
+    /* The code for a subquery should only be generated once. */
+    if( pSubq->addrFillSub!=0 ) continue;
+
+    /* Increment Parse.nHeight by the height of the largest expression
+    ** tree referred to by this, the parent select. The child select
+    ** may contain expression trees of at most
+    ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
+    ** more conservative than necessary, but much easier than enforcing
+    ** an exact limit.
+    */
+    pParse->nHeight += sqlite3SelectExprHeight(p);
+
+    /* Make copies of constant WHERE-clause terms in the outer query down
+    ** inside the subquery.  This can help the subquery to run more efficiently.
+    ** This is the "predicate push-down optimization".  tag-select-0420
+    */
+    if( OptimizationEnabled(db, SQLITE_PushDown)
+     && (pItem->fg.isCte==0
+         || (pItem->u2.pCteUse->eM10d!=M10d_Yes && pItem->u2.pCteUse->nUse<2))
+     && pushDownWhereTerms(pParse, pSub, p->pWhere, pTabList, i)
+    ){
+#if TREETRACE_ENABLED
+      if( sqlite3TreeTrace & 0x4000 ){
+        TREETRACE(0x4000,pParse,p,
+            ("After WHERE-clause push-down into subquery %d:\n", pSub->selId));
+        sqlite3TreeViewSelect(0, p, 0);
+      }
+#endif
+      assert( pSubq->pSelect && (pSub->selFlags & SF_PushDown)!=0 );
+    }else{
+      TREETRACE(0x4000,pParse,p,("WHERE-clause push-down not possible\n"));
+    }
+
+    /* Convert unused result columns of the subquery into simple NULL
+    ** expressions, to avoid unneeded searching and computation.
+    ** tag-select-0440
+    */
+    if( OptimizationEnabled(db, SQLITE_NullUnusedCols)
+     && disableUnusedSubqueryResultColumns(pItem)
+    ){
+#if TREETRACE_ENABLED
+      if( sqlite3TreeTrace & 0x4000 ){
+        TREETRACE(0x4000,pParse,p,
+            ("Change unused result columns to NULL for subquery %d:\n",
+             pSub->selId));
+        sqlite3TreeViewSelect(0, p, 0);
+      }
+#endif
+    }
+
+    zSavedAuthContext = pParse->zAuthContext;
+    pParse->zAuthContext = pItem->zName;
+
+    /* Generate byte-code to implement the subquery  tag-select-0480
+    */
+    if( fromClauseTermCanBeCoroutine(pParse, pTabList, i, p->selFlags) ){
+      /* Implement a co-routine that will return a single row of the result
+      ** set on each invocation.  tag-select-0482
+      */
+      int addrTop = sqlite3VdbeCurrentAddr(v)+1;
+
+      pSubq->regReturn = ++pParse->nMem;
+      sqlite3VdbeAddOp3(v, OP_InitCoroutine, pSubq->regReturn, 0, addrTop);
+      VdbeComment((v, "%!S", pItem));
+      pSubq->addrFillSub = addrTop;
+      sqlite3SelectDestInit(&dest, SRT_Coroutine, pSubq->regReturn);
+      ExplainQueryPlan((pParse, 1, "CO-ROUTINE %!S", pItem));
+      sqlite3Select(pParse, pSub, &dest);
+      pItem->pSTab->nRowLogEst = pSub->nSelectRow;
+      pItem->fg.viaCoroutine = 1;
+      pSubq->regResult = dest.iSdst;
+      sqlite3VdbeEndCoroutine(v, pSubq->regReturn);
+      VdbeComment((v, "end %!S", pItem));
+      sqlite3VdbeJumpHere(v, addrTop-1);
+      sqlite3ClearTempRegCache(pParse);
+    }else if( pItem->fg.isCte && pItem->u2.pCteUse->addrM9e>0 ){
+      /* This is a CTE for which materialization code has already been
+      ** generated.  Invoke the subroutine to compute the materialization,
+      ** then make the pItem->iCursor be a copy of the ephemeral table that
+      ** holds the result of the materialization. tag-select-0484 */
+      CteUse *pCteUse = pItem->u2.pCteUse;
+      sqlite3VdbeAddOp2(v, OP_Gosub, pCteUse->regRtn, pCteUse->addrM9e);
+      if( pItem->iCursor!=pCteUse->iCur ){
+        sqlite3VdbeAddOp2(v, OP_OpenDup, pItem->iCursor, pCteUse->iCur);
+        VdbeComment((v, "%!S", pItem));
+      }
+      pSub->nSelectRow = pCteUse->nRowEst;
+    }else if( (pPrior = isSelfJoinView(pTabList, pItem, 0, i))!=0 ){
+      /* This view has already been materialized by a prior entry in
+      ** this same FROM clause.  Reuse it.  tag-select-0486 */
+      Subquery *pPriorSubq;
+      assert( pPrior->fg.isSubquery );
+      pPriorSubq = pPrior->u4.pSubq;
+      assert( pPriorSubq!=0 );
+      if( pPriorSubq->addrFillSub ){
+        sqlite3VdbeAddOp2(v, OP_Gosub, pPriorSubq->regReturn,
+                                       pPriorSubq->addrFillSub);
+      }
+      sqlite3VdbeAddOp2(v, OP_OpenDup, pItem->iCursor, pPrior->iCursor);
+      pSub->nSelectRow = pPriorSubq->pSelect->nSelectRow;
+    }else{
+      /* Materialize the view.  If the view is not correlated, generate a
+      ** subroutine to do the materialization so that subsequent uses of
+      ** the same view can reuse the materialization.  tag-select-0488 */
+      int topAddr;
+      int onceAddr = 0;
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+      int addrExplain;
+#endif
+
+      pSubq->regReturn = ++pParse->nMem;
+      topAddr = sqlite3VdbeAddOp0(v, OP_Goto);
+      pSubq->addrFillSub = topAddr+1;
+      pItem->fg.isMaterialized = 1;
+      if( pItem->fg.isCorrelated==0 ){
+        /* If the subquery is not correlated and if we are not inside of
+        ** a trigger, then we only need to compute the value of the subquery
+        ** once. */
+        onceAddr = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+        VdbeComment((v, "materialize %!S", pItem));
+      }else{
+        VdbeNoopComment((v, "materialize %!S", pItem));
+      }
+      sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
+
+      ExplainQueryPlan2(addrExplain, (pParse, 1, "MATERIALIZE %!S", pItem));
+      sqlite3Select(pParse, pSub, &dest);
+      pItem->pSTab->nRowLogEst = pSub->nSelectRow;
+      if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
+      sqlite3VdbeAddOp2(v, OP_Return, pSubq->regReturn, topAddr+1);
+      VdbeComment((v, "end %!S", pItem));
+      sqlite3VdbeScanStatusRange(v, addrExplain, addrExplain, -1);
+      sqlite3VdbeJumpHere(v, topAddr);
+      sqlite3ClearTempRegCache(pParse);
+      if( pItem->fg.isCte && pItem->fg.isCorrelated==0 ){
+        CteUse *pCteUse = pItem->u2.pCteUse;
+        pCteUse->addrM9e = pSubq->addrFillSub;
+        pCteUse->regRtn = pSubq->regReturn;
+        pCteUse->iCur = pItem->iCursor;
+        pCteUse->nRowEst = pSub->nSelectRow;
+      }
+    }
+    if( db->mallocFailed ) goto select_end;
+    pParse->nHeight -= sqlite3SelectExprHeight(p);
+    pParse->zAuthContext = zSavedAuthContext;
+#endif
+  }
+
+  /* Various elements of the SELECT copied into local variables for
+  ** convenience */
+  pEList = p->pEList;
+  pWhere = p->pWhere;
+  pGroupBy = p->pGroupBy;
+  pHaving = p->pHaving;
+  sDistinct.isTnct = (p->selFlags & SF_Distinct)!=0;
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x8000 ){
+    TREETRACE(0x8000,pParse,p,("After all FROM-clause analysis:\n"));
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+
+  /* tag-select-0500
+  **
+  ** If the query is DISTINCT with an ORDER BY but is not an aggregate, and
+  ** if the select-list is the same as the ORDER BY list, then this query
+  ** can be rewritten as a GROUP BY. In other words, this:
+  **
+  **     SELECT DISTINCT xyz FROM ... ORDER BY xyz
+  **
+  ** is transformed to:
+  **
+  **     SELECT xyz FROM ... GROUP BY xyz ORDER BY xyz
+  **
+  ** The second form is preferred as a single index (or temp-table) may be
+  ** used for both the ORDER BY and DISTINCT processing. As originally
+  ** written the query must use a temp-table for at least one of the ORDER
+  ** BY and DISTINCT, and an index or separate temp-table for the other.
+  */
+  if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct
+   && sqlite3ExprListCompare(sSort.pOrderBy, pEList, -1)==0
+   && OptimizationEnabled(db, SQLITE_GroupByOrder)
+#ifndef SQLITE_OMIT_WINDOWFUNC
+   && p->pWin==0
+#endif
+  ){
+    p->selFlags &= ~SF_Distinct;
+    pGroupBy = p->pGroupBy = sqlite3ExprListDup(db, pEList, 0);
+    if( pGroupBy ){
+      for(i=0; i<pGroupBy->nExpr; i++){
+        pGroupBy->a[i].u.x.iOrderByCol = i+1;
+      }
+    }
+    p->selFlags |= SF_Aggregate;
+    /* Notice that even thought SF_Distinct has been cleared from p->selFlags,
+    ** the sDistinct.isTnct is still set.  Hence, isTnct represents the
+    ** original setting of the SF_Distinct flag, not the current setting */
+    assert( sDistinct.isTnct );
+    sDistinct.isTnct = 2;
+
+#if TREETRACE_ENABLED
+    if( sqlite3TreeTrace & 0x20000 ){
+      TREETRACE(0x20000,pParse,p,("Transform DISTINCT into GROUP BY:\n"));
+      sqlite3TreeViewSelect(0, p, 0);
+    }
+#endif
+  }
+
+  /* If there is an ORDER BY clause, then create an ephemeral index to
+  ** do the sorting.  But this sorting ephemeral index might end up
+  ** being unused if the data can be extracted in pre-sorted order.
+  ** If that is the case, then the OP_OpenEphemeral instruction will be
+  ** changed to an OP_Noop once we figure out that the sorting index is
+  ** not needed.  The sSort.addrSortIndex variable is used to facilitate
+  ** that change.  tag-select-0600
+  */
+  if( sSort.pOrderBy ){
+    KeyInfo *pKeyInfo;
+    pKeyInfo = sqlite3KeyInfoFromExprList(
+        pParse, sSort.pOrderBy, 0, pEList->nExpr);
+    sSort.iECursor = pParse->nTab++;
+    sSort.addrSortIndex =
+      sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+          sSort.iECursor, sSort.pOrderBy->nExpr+1+pEList->nExpr, 0,
+          (char*)pKeyInfo, P4_KEYINFO
+      );
+  }else{
+    sSort.addrSortIndex = -1;
+  }
+
+  /* If the output is destined for a temporary table, open that table.
+  ** tag-select-0630
+  */
+  if( pDest->eDest==SRT_EphemTab ){
+    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iSDParm, pEList->nExpr);
+    if( p->selFlags & SF_NestedFrom ){
+      /* Delete or NULL-out result columns that will never be used */
+      int ii;
+      for(ii=pEList->nExpr-1; ii>0 && pEList->a[ii].fg.bUsed==0; ii--){
+        sqlite3ExprDelete(db, pEList->a[ii].pExpr);
+        sqlite3DbFree(db, pEList->a[ii].zEName);
+        pEList->nExpr--;
+      }
+      for(ii=0; ii<pEList->nExpr; ii++){
+        if( pEList->a[ii].fg.bUsed==0 ) pEList->a[ii].pExpr->op = TK_NULL;
+      }
+    }
+  }
+
+  /* Set the limiter.  tag-select-0650
+  */
+  iEnd = sqlite3VdbeMakeLabel(pParse);
+  if( (p->selFlags & SF_FixedLimit)==0 ){
+    p->nSelectRow = 320;  /* 4 billion rows */
+  }
+  if( p->pLimit ) computeLimitRegisters(pParse, p, iEnd);
+  if( p->iLimit==0 && sSort.addrSortIndex>=0 ){
+    sqlite3VdbeChangeOpcode(v, sSort.addrSortIndex, OP_SorterOpen);
+    sSort.sortFlags |= SORTFLAG_UseSorter;
+  }
+
+  /* Open an ephemeral index to use for the distinct set. tag-select-0680
+  */
+  if( p->selFlags & SF_Distinct ){
+    sDistinct.tabTnct = pParse->nTab++;
+    sDistinct.addrTnct = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
+                       sDistinct.tabTnct, 0, 0,
+                       (char*)sqlite3KeyInfoFromExprList(pParse, p->pEList,0,0),
+                       P4_KEYINFO);
+    sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
+    sDistinct.eTnctType = WHERE_DISTINCT_UNORDERED;
+  }else{
+    sDistinct.eTnctType = WHERE_DISTINCT_NOOP;
+  }
+
+  if( !isAgg && pGroupBy==0 ){
+    /* No aggregate functions and no GROUP BY clause.  tag-select-0700 */
+    u16 wctrlFlags = (sDistinct.isTnct ? WHERE_WANT_DISTINCT : 0)
+                   | (p->selFlags & SF_FixedLimit);
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    Window *pWin = p->pWin;      /* Main window object (or NULL) */
+    if( pWin ){
+      sqlite3WindowCodeInit(pParse, p);
+    }
+#endif
+    assert( WHERE_USE_LIMIT==SF_FixedLimit );
+
+
+    /* Begin the database scan. */
+    TREETRACE(0x2,pParse,p,("WhereBegin\n"));
+    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, sSort.pOrderBy,
+                               p->pEList, p, wctrlFlags, p->nSelectRow);
+    if( pWInfo==0 ) goto select_end;
+    if( sqlite3WhereOutputRowCount(pWInfo) < p->nSelectRow ){
+      p->nSelectRow = sqlite3WhereOutputRowCount(pWInfo);
+    }
+    if( sDistinct.isTnct && sqlite3WhereIsDistinct(pWInfo) ){
+      sDistinct.eTnctType = sqlite3WhereIsDistinct(pWInfo);
+    }
+    if( sSort.pOrderBy ){
+      sSort.nOBSat = sqlite3WhereIsOrdered(pWInfo);
+      sSort.labelOBLopt = sqlite3WhereOrderByLimitOptLabel(pWInfo);
+      if( sSort.nOBSat==sSort.pOrderBy->nExpr ){
+        sSort.pOrderBy = 0;
+      }
+    }
+    TREETRACE(0x2,pParse,p,("WhereBegin returns\n"));
+
+    /* If sorting index that was created by a prior OP_OpenEphemeral
+    ** instruction ended up not being needed, then change the OP_OpenEphemeral
+    ** into an OP_Noop.
+    */
+    if( sSort.addrSortIndex>=0 && sSort.pOrderBy==0 ){
+      sqlite3VdbeChangeToNoop(v, sSort.addrSortIndex);
+    }
+
+    assert( p->pEList==pEList );
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( pWin ){
+      int addrGosub = sqlite3VdbeMakeLabel(pParse);
+      int iCont = sqlite3VdbeMakeLabel(pParse);
+      int iBreak = sqlite3VdbeMakeLabel(pParse);
+      int regGosub = ++pParse->nMem;
+
+      sqlite3WindowCodeStep(pParse, p, pWInfo, regGosub, addrGosub);
+
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, iBreak);
+      sqlite3VdbeResolveLabel(v, addrGosub);
+      VdbeNoopComment((v, "inner-loop subroutine"));
+      sSort.labelOBLopt = 0;
+      selectInnerLoop(pParse, p, -1, &sSort, &sDistinct, pDest, iCont, iBreak);
+      sqlite3VdbeResolveLabel(v, iCont);
+      sqlite3VdbeAddOp1(v, OP_Return, regGosub);
+      VdbeComment((v, "end inner-loop subroutine"));
+      sqlite3VdbeResolveLabel(v, iBreak);
+    }else
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+    {
+      /* Use the standard inner loop. */
+      selectInnerLoop(pParse, p, -1, &sSort, &sDistinct, pDest,
+          sqlite3WhereContinueLabel(pWInfo),
+          sqlite3WhereBreakLabel(pWInfo));
+
+      /* End the database scan loop.
+      */
+      TREETRACE(0x2,pParse,p,("WhereEnd\n"));
+      sqlite3WhereEnd(pWInfo);
+    }
+  }else{
+    /* This case is for when there exist aggregate functions or a GROUP BY
+    ** clause or both.  tag-select-0800 */
+    NameContext sNC;    /* Name context for processing aggregate information */
+    int iAMem;          /* First Mem address for storing current GROUP BY */
+    int iBMem;          /* First Mem address for previous GROUP BY */
+    int iUseFlag;       /* Mem address holding flag indicating that at least
+                        ** one row of the input to the aggregator has been
+                        ** processed */
+    int iAbortFlag;     /* Mem address which causes query abort if positive */
+    int groupBySort;    /* Rows come from source in GROUP BY order */
+    int addrEnd;        /* End of processing for this SELECT */
+    int sortPTab = 0;   /* Pseudotable used to decode sorting results */
+    int sortOut = 0;    /* Output register from the sorter */
+    int orderByGrp = 0; /* True if the GROUP BY and ORDER BY are the same */
+
+    /* Remove any and all aliases between the result set and the
+    ** GROUP BY clause.
+    */
+    if( pGroupBy ){
+      int k;                        /* Loop counter */
+      struct ExprList_item *pItem;  /* For looping over expression in a list */
+
+      for(k=p->pEList->nExpr, pItem=p->pEList->a; k>0; k--, pItem++){
+        pItem->u.x.iAlias = 0;
+      }
+      for(k=pGroupBy->nExpr, pItem=pGroupBy->a; k>0; k--, pItem++){
+        pItem->u.x.iAlias = 0;
+      }
+      assert( 66==sqlite3LogEst(100) );
+      if( p->nSelectRow>66 ) p->nSelectRow = 66;
+
+      /* If there is both a GROUP BY and an ORDER BY clause and they are
+      ** identical, then it may be possible to disable the ORDER BY clause
+      ** on the grounds that the GROUP BY will cause elements to come out
+      ** in the correct order. It also may not - the GROUP BY might use a
+      ** database index that causes rows to be grouped together as required
+      ** but not actually sorted. Either way, record the fact that the
+      ** ORDER BY and GROUP BY clauses are the same by setting the orderByGrp
+      ** variable.  */
+      if( sSort.pOrderBy && pGroupBy->nExpr==sSort.pOrderBy->nExpr ){
+        int ii;
+        /* The GROUP BY processing doesn't care whether rows are delivered in
+        ** ASC or DESC order - only that each group is returned contiguously.
+        ** So set the ASC/DESC flags in the GROUP BY to match those in the
+        ** ORDER BY to maximize the chances of rows being delivered in an
+        ** order that makes the ORDER BY redundant.  */
+        for(ii=0; ii<pGroupBy->nExpr; ii++){
+          u8 sortFlags;
+          sortFlags = sSort.pOrderBy->a[ii].fg.sortFlags & KEYINFO_ORDER_DESC;
+          pGroupBy->a[ii].fg.sortFlags = sortFlags;
+        }
+        if( sqlite3ExprListCompare(pGroupBy, sSort.pOrderBy, -1)==0 ){
+          orderByGrp = 1;
+        }
+      }
+    }else{
+      assert( 0==sqlite3LogEst(1) );
+      p->nSelectRow = 0;
+    }
+
+    /* Create a label to jump to when we want to abort the query */
+    addrEnd = sqlite3VdbeMakeLabel(pParse);
+
+    /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
+    ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
+    ** SELECT statement.
+    */
+    pAggInfo = sqlite3DbMallocZero(db, sizeof(*pAggInfo) );
+    if( pAggInfo ){
+      sqlite3ParserAddCleanup(pParse, agginfoFree, pAggInfo);
+      testcase( pParse->earlyCleanup );
+    }
+    if( db->mallocFailed ){
+      goto select_end;
+    }
+    pAggInfo->selId = p->selId;
+#ifdef SQLITE_DEBUG
+    pAggInfo->pSelect = p;
+#endif
+    memset(&sNC, 0, sizeof(sNC));
+    sNC.pParse = pParse;
+    sNC.pSrcList = pTabList;
+    sNC.uNC.pAggInfo = pAggInfo;
+    VVA_ONLY( sNC.ncFlags = NC_UAggInfo; )
+    pAggInfo->nSortingColumn = pGroupBy ? pGroupBy->nExpr : 0;
+    pAggInfo->pGroupBy = pGroupBy;
+    sqlite3ExprAnalyzeAggList(&sNC, pEList);
+    sqlite3ExprAnalyzeAggList(&sNC, sSort.pOrderBy);
+    if( pHaving ){
+      if( pGroupBy ){
+        assert( pWhere==p->pWhere );
+        assert( pHaving==p->pHaving );
+        assert( pGroupBy==p->pGroupBy );
+        havingToWhere(pParse, p);
+        pWhere = p->pWhere;
+      }
+      sqlite3ExprAnalyzeAggregates(&sNC, pHaving);
+    }
+    pAggInfo->nAccumulator = pAggInfo->nColumn;
+    if( p->pGroupBy==0 && p->pHaving==0 && pAggInfo->nFunc==1 ){
+      minMaxFlag = minMaxQuery(db, pAggInfo->aFunc[0].pFExpr, &pMinMaxOrderBy);
+    }else{
+      minMaxFlag = WHERE_ORDERBY_NORMAL;
+    }
+    analyzeAggFuncArgs(pAggInfo, &sNC);
+    if( db->mallocFailed ) goto select_end;
+#if TREETRACE_ENABLED
+    if( sqlite3TreeTrace & 0x20 ){
+      TREETRACE(0x20,pParse,p,("After aggregate analysis %p:\n", pAggInfo));
+      sqlite3TreeViewSelect(0, p, 0);
+      if( minMaxFlag ){
+        sqlite3DebugPrintf("MIN/MAX Optimization (0x%02x) adds:\n", minMaxFlag);
+        sqlite3TreeViewExprList(0, pMinMaxOrderBy, 0, "ORDERBY");
+      }
+      printAggInfo(pAggInfo);
+    }
+#endif
+
+
+    /* Processing for aggregates with GROUP BY is very different and
+    ** much more complex than aggregates without a GROUP BY.  tag-select-0810
+    */
+    if( pGroupBy ){
+      KeyInfo *pKeyInfo;  /* Keying information for the group by clause */
+      int addr1;          /* A-vs-B comparison jump */
+      int addrOutputRow;  /* Start of subroutine that outputs a result row */
+      int regOutputRow;   /* Return address register for output subroutine */
+      int addrSetAbort;   /* Set the abort flag and return */
+      int addrTopOfLoop;  /* Top of the input loop */
+      int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
+      int addrReset;      /* Subroutine for resetting the accumulator */
+      int regReset;       /* Return address register for reset subroutine */
+      ExprList *pDistinct = 0;
+      u16 distFlag = 0;
+      int eDist = WHERE_DISTINCT_NOOP;
+
+      if( pAggInfo->nFunc==1
+       && pAggInfo->aFunc[0].iDistinct>=0
+       && ALWAYS(pAggInfo->aFunc[0].pFExpr!=0)
+       && ALWAYS(ExprUseXList(pAggInfo->aFunc[0].pFExpr))
+       && pAggInfo->aFunc[0].pFExpr->x.pList!=0
+      ){
+        Expr *pExpr = pAggInfo->aFunc[0].pFExpr->x.pList->a[0].pExpr;
+        pExpr = sqlite3ExprDup(db, pExpr, 0);
+        pDistinct = sqlite3ExprListDup(db, pGroupBy, 0);
+        pDistinct = sqlite3ExprListAppend(pParse, pDistinct, pExpr);
+        distFlag = pDistinct ? (WHERE_WANT_DISTINCT|WHERE_AGG_DISTINCT) : 0;
+      }
+
+      /* If there is a GROUP BY clause we might need a sorting index to
+      ** implement it.  Allocate that sorting index now.  If it turns out
+      ** that we do not need it after all, the OP_SorterOpen instruction
+      ** will be converted into a Noop.
+      */
+      pAggInfo->sortingIdx = pParse->nTab++;
+      pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pGroupBy,
+                                            0, pAggInfo->nColumn);
+      addrSortingIdx = sqlite3VdbeAddOp4(v, OP_SorterOpen,
+          pAggInfo->sortingIdx, pAggInfo->nSortingColumn,
+          0, (char*)pKeyInfo, P4_KEYINFO);
+
+      /* Initialize memory locations used by GROUP BY aggregate processing
+      */
+      iUseFlag = ++pParse->nMem;
+      iAbortFlag = ++pParse->nMem;
+      regOutputRow = ++pParse->nMem;
+      addrOutputRow = sqlite3VdbeMakeLabel(pParse);
+      regReset = ++pParse->nMem;
+      addrReset = sqlite3VdbeMakeLabel(pParse);
+      iAMem = pParse->nMem + 1;
+      pParse->nMem += pGroupBy->nExpr;
+      iBMem = pParse->nMem + 1;
+      pParse->nMem += pGroupBy->nExpr;
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, iAbortFlag);
+      VdbeComment((v, "clear abort flag"));
+      sqlite3VdbeAddOp3(v, OP_Null, 0, iAMem, iAMem+pGroupBy->nExpr-1);
+
+      /* Begin a loop that will extract all source rows in GROUP BY order.
+      ** This might involve two separate loops with an OP_Sort in between, or
+      ** it might be a single loop that uses an index to extract information
+      ** in the right order to begin with.
+      */
+      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
+      TREETRACE(0x2,pParse,p,("WhereBegin\n"));
+      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pGroupBy, pDistinct,
+          p, (sDistinct.isTnct==2 ? WHERE_DISTINCTBY : WHERE_GROUPBY)
+          |  (orderByGrp ? WHERE_SORTBYGROUP : 0) | distFlag, 0
+      );
+      if( pWInfo==0 ){
+        sqlite3ExprListDelete(db, pDistinct);
+        goto select_end;
+      }
+      if( pParse->pIdxEpr ){
+        optimizeAggregateUseOfIndexedExpr(pParse, p, pAggInfo, &sNC);
+      }
+      assignAggregateRegisters(pParse, pAggInfo);
+      eDist = sqlite3WhereIsDistinct(pWInfo);
+      TREETRACE(0x2,pParse,p,("WhereBegin returns\n"));
+      if( sqlite3WhereIsOrdered(pWInfo)==pGroupBy->nExpr ){
+        /* The optimizer is able to deliver rows in group by order so
+        ** we do not have to sort.  The OP_OpenEphemeral table will be
+        ** cancelled later because we still need to use the pKeyInfo
+        */
+        groupBySort = 0;
+      }else{
+        /* Rows are coming out in undetermined order.  We have to push
+        ** each row into a sorting index, terminate the first loop,
+        ** then loop over the sorting index in order to get the output
+        ** in sorted order
+        */
+        int regBase;
+        int regRecord;
+        int nCol;
+        int nGroupBy;
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+        int addrExp;              /* Address of OP_Explain instruction */
+#endif
+        ExplainQueryPlan2(addrExp, (pParse, 0, "USE TEMP B-TREE FOR %s",
+            (sDistinct.isTnct && (p->selFlags&SF_Distinct)==0) ?
+                    "DISTINCT" : "GROUP BY"
+        ));
+
+        groupBySort = 1;
+        nGroupBy = pGroupBy->nExpr;
+        nCol = nGroupBy;
+        j = nGroupBy;
+        for(i=0; i<pAggInfo->nColumn; i++){
+          if( pAggInfo->aCol[i].iSorterColumn>=j ){
+            nCol++;
+            j++;
+          }
+        }
+        regBase = sqlite3GetTempRange(pParse, nCol);
+        sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0, 0);
+        j = nGroupBy;
+        pAggInfo->directMode = 1;
+        for(i=0; i<pAggInfo->nColumn; i++){
+          struct AggInfo_col *pCol = &pAggInfo->aCol[i];
+          if( pCol->iSorterColumn>=j ){
+            sqlite3ExprCode(pParse, pCol->pCExpr, j + regBase);
+            j++;
+          }
+        }
+        pAggInfo->directMode = 0;
+        regRecord = sqlite3GetTempReg(pParse);
+        sqlite3VdbeScanStatusCounters(v, addrExp, 0, sqlite3VdbeCurrentAddr(v));
+        sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord);
+        sqlite3VdbeAddOp2(v, OP_SorterInsert, pAggInfo->sortingIdx, regRecord);
+        sqlite3VdbeScanStatusRange(v, addrExp, sqlite3VdbeCurrentAddr(v)-2, -1);
+        sqlite3ReleaseTempReg(pParse, regRecord);
+        sqlite3ReleaseTempRange(pParse, regBase, nCol);
+        TREETRACE(0x2,pParse,p,("WhereEnd\n"));
+        sqlite3WhereEnd(pWInfo);
+        pAggInfo->sortingIdxPTab = sortPTab = pParse->nTab++;
+        sortOut = sqlite3GetTempReg(pParse);
+        sqlite3VdbeScanStatusCounters(v, addrExp, sqlite3VdbeCurrentAddr(v), 0);
+        sqlite3VdbeAddOp3(v, OP_OpenPseudo, sortPTab, sortOut, nCol);
+        sqlite3VdbeAddOp2(v, OP_SorterSort, pAggInfo->sortingIdx, addrEnd);
+        VdbeComment((v, "GROUP BY sort")); VdbeCoverage(v);
+        pAggInfo->useSortingIdx = 1;
+        sqlite3VdbeScanStatusRange(v, addrExp, -1, sortPTab);
+        sqlite3VdbeScanStatusRange(v, addrExp, -1, pAggInfo->sortingIdx);
+      }
+
+      /* If there are entries in pAgggInfo->aFunc[] that contain subexpressions
+      ** that are indexed (and that were previously identified and tagged
+      ** in optimizeAggregateUseOfIndexedExpr()) then those subexpressions
+      ** must now be converted into a TK_AGG_COLUMN node so that the value
+      ** is correctly pulled from the index rather than being recomputed. */
+      if( pParse->pIdxEpr ){
+        aggregateConvertIndexedExprRefToColumn(pAggInfo);
+#if TREETRACE_ENABLED
+        if( sqlite3TreeTrace & 0x20 ){
+          TREETRACE(0x20, pParse, p,
+             ("AggInfo function expressions converted to reference index\n"));
+          sqlite3TreeViewSelect(0, p, 0);
+          printAggInfo(pAggInfo);
+        }
+#endif
+      }
+
+      /* If the index or temporary table used by the GROUP BY sort
+      ** will naturally deliver rows in the order required by the ORDER BY
+      ** clause, cancel the ephemeral table open coded earlier.
+      **
+      ** This is an optimization - the correct answer should result regardless.
+      ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER to
+      ** disable this optimization for testing purposes.  */
+      if( orderByGrp && OptimizationEnabled(db, SQLITE_GroupByOrder)
+       && (groupBySort || sqlite3WhereIsSorted(pWInfo))
+      ){
+        sSort.pOrderBy = 0;
+        sqlite3VdbeChangeToNoop(v, sSort.addrSortIndex);
+      }
+
+      /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
+      ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
+      ** Then compare the current GROUP BY terms against the GROUP BY terms
+      ** from the previous row currently stored in a0, a1, a2...
+      */
+      addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
+      if( groupBySort ){
+        sqlite3VdbeAddOp3(v, OP_SorterData, pAggInfo->sortingIdx,
+                          sortOut, sortPTab);
+      }
+      for(j=0; j<pGroupBy->nExpr; j++){
+        int iOrderByCol = pGroupBy->a[j].u.x.iOrderByCol;
+
+        if( groupBySort ){
+          sqlite3VdbeAddOp3(v, OP_Column, sortPTab, j, iBMem+j);
+        }else{
+          pAggInfo->directMode = 1;
+          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
+        }
+
+        if( iOrderByCol ){
+          Expr *pX = p->pEList->a[iOrderByCol-1].pExpr;
+          Expr *pBase = sqlite3ExprSkipCollateAndLikely(pX);
+          if( ALWAYS(pBase!=0)
+           && pBase->op!=TK_AGG_COLUMN
+           && pBase->op!=TK_REGISTER
+          ){
+            sqlite3ExprToRegister(pX, iAMem+j);
+          }
+        }
+      }
+      sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr,
+                          (char*)sqlite3KeyInfoRef(pKeyInfo), P4_KEYINFO);
+      addr1 = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp3(v, OP_Jump, addr1+1, 0, addr1+1); VdbeCoverage(v);
+
+      /* Generate code that runs whenever the GROUP BY changes.
+      ** Changes in the GROUP BY are detected by the previous code
+      ** block.  If there were no changes, this block is skipped.
+      **
+      ** This code copies current group by terms in b0,b1,b2,...
+      ** over to a0,a1,a2.  It then calls the output subroutine
+      ** and resets the aggregate accumulator registers in preparation
+      ** for the next GROUP BY batch.
+      */
+      sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
+      VdbeComment((v, "output one row"));
+      sqlite3ExprCodeMove(pParse, iBMem, iAMem, pGroupBy->nExpr);
+      sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd); VdbeCoverage(v);
+      VdbeComment((v, "check abort flag"));
+      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
+      VdbeComment((v, "reset accumulator"));
+
+      /* Update the aggregate accumulators based on the content of
+      ** the current row
+      */
+      sqlite3VdbeJumpHere(v, addr1);
+      updateAccumulator(pParse, iUseFlag, pAggInfo, eDist);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag);
+      VdbeComment((v, "indicate data in accumulator"));
+
+      /* End of the loop
+      */
+      if( groupBySort ){
+        sqlite3VdbeAddOp2(v, OP_SorterNext, pAggInfo->sortingIdx,addrTopOfLoop);
+        VdbeCoverage(v);
+      }else{
+        TREETRACE(0x2,pParse,p,("WhereEnd\n"));
+        sqlite3WhereEnd(pWInfo);
+        sqlite3VdbeChangeToNoop(v, addrSortingIdx);
+      }
+      sqlite3ExprListDelete(db, pDistinct);
+
+      /* Output the final row of result
+      */
+      sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
+      VdbeComment((v, "output final row"));
+
+      /* Jump over the subroutines
+      */
+      sqlite3VdbeGoto(v, addrEnd);
+
+      /* Generate a subroutine that outputs a single row of the result
+      ** set.  This subroutine first looks at the iUseFlag.  If iUseFlag
+      ** is less than or equal to zero, the subroutine is a no-op.  If
+      ** the processing calls for the query to abort, this subroutine
+      ** increments the iAbortFlag memory location before returning in
+      ** order to signal the caller to abort.
+      */
+      addrSetAbort = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, iAbortFlag);
+      VdbeComment((v, "set abort flag"));
+      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
+      sqlite3VdbeResolveLabel(v, addrOutputRow);
+      addrOutputRow = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2);
+      VdbeCoverage(v);
+      VdbeComment((v, "Groupby result generator entry point"));
+      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
+      finalizeAggFunctions(pParse, pAggInfo);
+      sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
+      selectInnerLoop(pParse, p, -1, &sSort,
+                      &sDistinct, pDest,
+                      addrOutputRow+1, addrSetAbort);
+      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
+      VdbeComment((v, "end groupby result generator"));
+
+      /* Generate a subroutine that will reset the group-by accumulator
+      */
+      sqlite3VdbeResolveLabel(v, addrReset);
+      resetAccumulator(pParse, pAggInfo);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
+      VdbeComment((v, "indicate accumulator empty"));
+      sqlite3VdbeAddOp1(v, OP_Return, regReset);
+
+      if( distFlag!=0 && eDist!=WHERE_DISTINCT_NOOP ){
+        struct AggInfo_func *pF = &pAggInfo->aFunc[0];
+        fixDistinctOpenEph(pParse, eDist, pF->iDistinct, pF->iDistAddr);
+      }
+    } /* endif pGroupBy.  Begin aggregate queries without GROUP BY: */
+    else {
+      /* Aggregate functions without GROUP BY. tag-select-0820 */
+      Table *pTab;
+      if( (pTab = isSimpleCount(p, pAggInfo))!=0 ){
+        /* tag-select-0821
+        **
+        ** If isSimpleCount() returns a pointer to a Table structure, then
+        ** the SQL statement is of the form:
+        **
+        **   SELECT count(*) FROM <tbl>
+        **
+        ** where the Table structure returned represents table <tbl>.
+        **
+        ** This statement is so common that it is optimized specially. The
+        ** OP_Count instruction is executed either on the intkey table that
+        ** contains the data for table <tbl> or on one of its indexes. It
+        ** is better to execute the op on an index, as indexes are almost
+        ** always spread across less pages than their corresponding tables.
+        */
+        const int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+        const int iCsr = pParse->nTab++;     /* Cursor to scan b-tree */
+        Index *pIdx;                         /* Iterator variable */
+        KeyInfo *pKeyInfo = 0;               /* Keyinfo for scanned index */
+        Index *pBest = 0;                    /* Best index found so far */
+        Pgno iRoot = pTab->tnum;             /* Root page of scanned b-tree */
+
+        sqlite3CodeVerifySchema(pParse, iDb);
+        sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+
+        /* Search for the index that has the lowest scan cost.
+        **
+        ** (2011-04-15) Do not do a full scan of an unordered index.
+        **
+        ** (2013-10-03) Do not count the entries in a partial index.
+        **
+        ** In practice the KeyInfo structure will not be used. It is only
+        ** passed to keep OP_OpenRead happy.
+        */
+        if( !HasRowid(pTab) ) pBest = sqlite3PrimaryKeyIndex(pTab);
+        if( !p->pSrc->a[0].fg.notIndexed ){
+          for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+            if( pIdx->bUnordered==0
+             && pIdx->szIdxRow<pTab->szTabRow
+             && pIdx->pPartIdxWhere==0
+             && (!pBest || pIdx->szIdxRow<pBest->szIdxRow)
+            ){
+              pBest = pIdx;
+            }
+          }
+        }
+        if( pBest ){
+          iRoot = pBest->tnum;
+          pKeyInfo = sqlite3KeyInfoOfIndex(pParse, pBest);
+        }
+
+        /* Open a read-only cursor, execute the OP_Count, close the cursor. */
+        sqlite3VdbeAddOp4Int(v, OP_OpenRead, iCsr, (int)iRoot, iDb, 1);
+        if( pKeyInfo ){
+          sqlite3VdbeChangeP4(v, -1, (char *)pKeyInfo, P4_KEYINFO);
+        }
+        assignAggregateRegisters(pParse, pAggInfo);
+        sqlite3VdbeAddOp2(v, OP_Count, iCsr, AggInfoFuncReg(pAggInfo,0));
+        sqlite3VdbeAddOp1(v, OP_Close, iCsr);
+        explainSimpleCount(pParse, pTab, pBest);
+      }else{
+        /* The general case of an aggregate query without GROUP BY
+        ** tag-select-0822 */
+        int regAcc = 0;           /* "populate accumulators" flag */
+        ExprList *pDistinct = 0;
+        u16 distFlag = 0;
+        int eDist;
+
+        /* If there are accumulator registers but no min() or max() functions
+        ** without FILTER clauses, allocate register regAcc. Register regAcc
+        ** will contain 0 the first time the inner loop runs, and 1 thereafter.
+        ** The code generated by updateAccumulator() uses this to ensure
+        ** that the accumulator registers are (a) updated only once if
+        ** there are no min() or max functions or (b) always updated for the
+        ** first row visited by the aggregate, so that they are updated at
+        ** least once even if the FILTER clause means the min() or max()
+        ** function visits zero rows.  */
+        if( pAggInfo->nAccumulator ){
+          for(i=0; i<pAggInfo->nFunc; i++){
+            if( ExprHasProperty(pAggInfo->aFunc[i].pFExpr, EP_WinFunc) ){
+              continue;
+            }
+            if( pAggInfo->aFunc[i].pFunc->funcFlags&SQLITE_FUNC_NEEDCOLL ){
+              break;
+            }
+          }
+          if( i==pAggInfo->nFunc ){
+            regAcc = ++pParse->nMem;
+            sqlite3VdbeAddOp2(v, OP_Integer, 0, regAcc);
+          }
+        }else if( pAggInfo->nFunc==1 && pAggInfo->aFunc[0].iDistinct>=0 ){
+          assert( ExprUseXList(pAggInfo->aFunc[0].pFExpr) );
+          pDistinct = pAggInfo->aFunc[0].pFExpr->x.pList;
+          distFlag = pDistinct ? (WHERE_WANT_DISTINCT|WHERE_AGG_DISTINCT) : 0;
+        }
+        assignAggregateRegisters(pParse, pAggInfo);
+
+        /* This case runs if the aggregate has no GROUP BY clause.  The
+        ** processing is much simpler since there is only a single row
+        ** of output.
+        */
+        assert( p->pGroupBy==0 );
+        resetAccumulator(pParse, pAggInfo);
+
+        /* If this query is a candidate for the min/max optimization, then
+        ** minMaxFlag will have been previously set to either
+        ** WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX and pMinMaxOrderBy will
+        ** be an appropriate ORDER BY expression for the optimization.
+        */
+        assert( minMaxFlag==WHERE_ORDERBY_NORMAL || pMinMaxOrderBy!=0 );
+        assert( pMinMaxOrderBy==0 || pMinMaxOrderBy->nExpr==1 );
+
+        TREETRACE(0x2,pParse,p,("WhereBegin\n"));
+        pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pMinMaxOrderBy,
+                                   pDistinct, p, minMaxFlag|distFlag, 0);
+        if( pWInfo==0 ){
+          goto select_end;
+        }
+        TREETRACE(0x2,pParse,p,("WhereBegin returns\n"));
+        eDist = sqlite3WhereIsDistinct(pWInfo);
+        updateAccumulator(pParse, regAcc, pAggInfo, eDist);
+        if( eDist!=WHERE_DISTINCT_NOOP ){
+          struct AggInfo_func *pF = pAggInfo->aFunc;
+          if( pF ){
+            fixDistinctOpenEph(pParse, eDist, pF->iDistinct, pF->iDistAddr);
+          }
+        }
+
+        if( regAcc ) sqlite3VdbeAddOp2(v, OP_Integer, 1, regAcc);
+        if( minMaxFlag ){
+          sqlite3WhereMinMaxOptEarlyOut(v, pWInfo);
+        }
+        TREETRACE(0x2,pParse,p,("WhereEnd\n"));
+        sqlite3WhereEnd(pWInfo);
+        finalizeAggFunctions(pParse, pAggInfo);
+      }
+
+      sSort.pOrderBy = 0;
+      sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
+      selectInnerLoop(pParse, p, -1, 0, 0,
+                      pDest, addrEnd, addrEnd);
+    }
+    sqlite3VdbeResolveLabel(v, addrEnd);
+
+  } /* endif aggregate query */
+
+  if( sDistinct.eTnctType==WHERE_DISTINCT_UNORDERED ){
+    explainTempTable(pParse, "DISTINCT");
+  }
+
+  /* If there is an ORDER BY clause, then we need to sort the results
+  ** and send them to the callback one by one.  tag-select-0900
+  */
+  if( sSort.pOrderBy ){
+    assert( p->pEList==pEList );
+    generateSortTail(pParse, p, &sSort, pEList->nExpr, pDest);
+  }
+
+  /* Jump here to skip this query
+  */
+  sqlite3VdbeResolveLabel(v, iEnd);
+
+  /* The SELECT has been coded. If there is an error in the Parse structure,
+  ** set the return code to 1. Otherwise 0. */
+  rc = (pParse->nErr>0);
+
+  /* Control jumps to here if an error is encountered above, or upon
+  ** successful coding of the SELECT.
+  */
+select_end:
+  assert( db->mallocFailed==0 || db->mallocFailed==1 );
+  assert( db->mallocFailed==0 || pParse->nErr!=0 );
+  sqlite3ExprListDelete(db, pMinMaxOrderBy);
+#ifdef SQLITE_DEBUG
+  /* Internal self-checks.  tag-select-1000 */
+  if( pAggInfo && !db->mallocFailed ){
+#if TREETRACE_ENABLED
+    if( sqlite3TreeTrace & 0x20 ){
+      TREETRACE(0x20,pParse,p,("Finished with AggInfo\n"));
+      printAggInfo(pAggInfo);
+    }
+#endif
+    for(i=0; i<pAggInfo->nColumn; i++){
+      Expr *pExpr = pAggInfo->aCol[i].pCExpr;
+      if( pExpr==0 ) continue;
+      assert( pExpr->pAggInfo==pAggInfo );
+      assert( pExpr->iAgg==i );
+    }
+    for(i=0; i<pAggInfo->nFunc; i++){
+      Expr *pExpr = pAggInfo->aFunc[i].pFExpr;
+      assert( pExpr!=0 );
+      assert( pExpr->pAggInfo==pAggInfo );
+      assert( pExpr->iAgg==i );
+    }
+  }
+#endif
+
+#if TREETRACE_ENABLED
+  TREETRACE(0x1,pParse,p,("end processing\n"));
+  if( (sqlite3TreeTrace & 0x40000)!=0 && ExplainQueryPlanParent(pParse)==0 ){
+    sqlite3TreeViewSelect(0, p, 0);
+  }
+#endif
+  ExplainQueryPlanPop(pParse);
+  return rc;
+}
+
+/************** End of select.c **********************************************/
+/************** Begin file table.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the sqlite3_get_table() and sqlite3_free_table()
+** interface routines.  These are just wrappers around the main
+** interface routine of sqlite3_exec().
+**
+** These routines are in a separate files so that they will not be linked
+** if they are not used.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_GET_TABLE
+
+/*
+** This structure is used to pass data from sqlite3_get_table() through
+** to the callback function is uses to build the result.
+*/
+typedef struct TabResult {
+  char **azResult;   /* Accumulated output */
+  char *zErrMsg;     /* Error message text, if an error occurs */
+  u32 nAlloc;        /* Slots allocated for azResult[] */
+  u32 nRow;          /* Number of rows in the result */
+  u32 nColumn;       /* Number of columns in the result */
+  u32 nData;         /* Slots used in azResult[].  (nRow+1)*nColumn */
+  int rc;            /* Return code from sqlite3_exec() */
+} TabResult;
+
+/*
+** This routine is called once for each row in the result table.  Its job
+** is to fill in the TabResult structure appropriately, allocating new
+** memory as necessary.
+*/
+static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){
+  TabResult *p = (TabResult*)pArg;  /* Result accumulator */
+  int need;                         /* Slots needed in p->azResult[] */
+  int i;                            /* Loop counter */
+  char *z;                          /* A single column of result */
+
+  /* Make sure there is enough space in p->azResult to hold everything
+  ** we need to remember from this invocation of the callback.
+  */
+  if( p->nRow==0 && argv!=0 ){
+    need = nCol*2;
+  }else{
+    need = nCol;
+  }
+  if( p->nData + need > p->nAlloc ){
+    char **azNew;
+    p->nAlloc = p->nAlloc*2 + need;
+    azNew = sqlite3Realloc( p->azResult, sizeof(char*)*p->nAlloc );
+    if( azNew==0 ) goto malloc_failed;
+    p->azResult = azNew;
+  }
+
+  /* If this is the first row, then generate an extra row containing
+  ** the names of all columns.
+  */
+  if( p->nRow==0 ){
+    p->nColumn = nCol;
+    for(i=0; i<nCol; i++){
+      z = sqlite3_mprintf("%s", colv[i]);
+      if( z==0 ) goto malloc_failed;
+      p->azResult[p->nData++] = z;
+    }
+  }else if( (int)p->nColumn!=nCol ){
+    sqlite3_free(p->zErrMsg);
+    p->zErrMsg = sqlite3_mprintf(
+       "sqlite3_get_table() called with two or more incompatible queries"
+    );
+    p->rc = SQLITE_ERROR;
+    return 1;
+  }
+
+  /* Copy over the row data
+  */
+  if( argv!=0 ){
+    for(i=0; i<nCol; i++){
+      if( argv[i]==0 ){
+        z = 0;
+      }else{
+        int n = sqlite3Strlen30(argv[i])+1;
+        z = sqlite3_malloc64( n );
+        if( z==0 ) goto malloc_failed;
+        memcpy(z, argv[i], n);
+      }
+      p->azResult[p->nData++] = z;
+    }
+    p->nRow++;
+  }
+  return 0;
+
+malloc_failed:
+  p->rc = SQLITE_NOMEM_BKPT;
+  return 1;
+}
+
+/*
+** Query the database.  But instead of invoking a callback for each row,
+** malloc() for space to hold the result and return the entire results
+** at the conclusion of the call.
+**
+** The result that is written to ***pazResult is held in memory obtained
+** from malloc().  But the caller cannot free this memory directly.
+** Instead, the entire table should be passed to sqlite3_free_table() when
+** the calling procedure is finished using it.
+*/
+SQLITE_API int sqlite3_get_table(
+  sqlite3 *db,                /* The database on which the SQL executes */
+  const char *zSql,           /* The SQL to be executed */
+  char ***pazResult,          /* Write the result table here */
+  int *pnRow,                 /* Write the number of rows in the result here */
+  int *pnColumn,              /* Write the number of columns of result here */
+  char **pzErrMsg             /* Write error messages here */
+){
+  int rc;
+  TabResult res;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || pazResult==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *pazResult = 0;
+  if( pnColumn ) *pnColumn = 0;
+  if( pnRow ) *pnRow = 0;
+  if( pzErrMsg ) *pzErrMsg = 0;
+  res.zErrMsg = 0;
+  res.nRow = 0;
+  res.nColumn = 0;
+  res.nData = 1;
+  res.nAlloc = 20;
+  res.rc = SQLITE_OK;
+  res.azResult = sqlite3_malloc64(sizeof(char*)*res.nAlloc );
+  if( res.azResult==0 ){
+     db->errCode = SQLITE_NOMEM;
+     return SQLITE_NOMEM_BKPT;
+  }
+  res.azResult[0] = 0;
+  rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg);
+  assert( sizeof(res.azResult[0])>= sizeof(res.nData) );
+  res.azResult[0] = SQLITE_INT_TO_PTR(res.nData);
+  if( (rc&0xff)==SQLITE_ABORT ){
+    sqlite3_free_table(&res.azResult[1]);
+    if( res.zErrMsg ){
+      if( pzErrMsg ){
+        sqlite3_free(*pzErrMsg);
+        *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg);
+      }
+      sqlite3_free(res.zErrMsg);
+    }
+    db->errCode = res.rc;  /* Assume 32-bit assignment is atomic */
+    return res.rc;
+  }
+  sqlite3_free(res.zErrMsg);
+  if( rc!=SQLITE_OK ){
+    sqlite3_free_table(&res.azResult[1]);
+    return rc;
+  }
+  if( res.nAlloc>res.nData ){
+    char **azNew;
+    azNew = sqlite3Realloc( res.azResult, sizeof(char*)*res.nData );
+    if( azNew==0 ){
+      sqlite3_free_table(&res.azResult[1]);
+      db->errCode = SQLITE_NOMEM;
+      return SQLITE_NOMEM_BKPT;
+    }
+    res.azResult = azNew;
+  }
+  *pazResult = &res.azResult[1];
+  if( pnColumn ) *pnColumn = res.nColumn;
+  if( pnRow ) *pnRow = res.nRow;
+  return rc;
+}
+
+/*
+** This routine frees the space the sqlite3_get_table() malloced.
+*/
+SQLITE_API void sqlite3_free_table(
+  char **azResult            /* Result returned from sqlite3_get_table() */
+){
+  if( azResult ){
+    int i, n;
+    azResult--;
+    assert( azResult!=0 );
+    n = SQLITE_PTR_TO_INT(azResult[0]);
+    for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); }
+    sqlite3_free(azResult);
+  }
+}
+
+#endif /* SQLITE_OMIT_GET_TABLE */
+
+/************** End of table.c ***********************************************/
+/************** Begin file trigger.c *****************************************/
+/*
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains the implementation for TRIGGERs
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_TRIGGER
+/*
+** Delete a linked list of TriggerStep structures.
+*/
+SQLITE_PRIVATE void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerStep){
+  while( pTriggerStep ){
+    TriggerStep * pTmp = pTriggerStep;
+    pTriggerStep = pTriggerStep->pNext;
+
+    sqlite3ExprDelete(db, pTmp->pWhere);
+    sqlite3ExprListDelete(db, pTmp->pExprList);
+    sqlite3SelectDelete(db, pTmp->pSelect);
+    sqlite3IdListDelete(db, pTmp->pIdList);
+    sqlite3UpsertDelete(db, pTmp->pUpsert);
+    sqlite3SrcListDelete(db, pTmp->pFrom);
+    sqlite3DbFree(db, pTmp->zSpan);
+
+    sqlite3DbFree(db, pTmp);
+  }
+}
+
+/*
+** Given table pTab, return a list of all the triggers attached to
+** the table. The list is connected by Trigger.pNext pointers.
+**
+** All of the triggers on pTab that are in the same database as pTab
+** are already attached to pTab->pTrigger.  But there might be additional
+** triggers on pTab in the TEMP schema.  This routine prepends all
+** TEMP triggers on pTab to the beginning of the pTab->pTrigger list
+** and returns the combined list.
+**
+** To state it another way:  This routine returns a list of all triggers
+** that fire off of pTab.  The list will include any TEMP triggers on
+** pTab as well as the triggers lised in pTab->pTrigger.
+*/
+SQLITE_PRIVATE Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){
+  Schema *pTmpSchema;       /* Schema of the pTab table */
+  Trigger *pList;           /* List of triggers to return */
+  HashElem *p;              /* Loop variable for TEMP triggers */
+
+  assert( pParse->disableTriggers==0 );
+  pTmpSchema = pParse->db->aDb[1].pSchema;
+  p = sqliteHashFirst(&pTmpSchema->trigHash);
+  pList = pTab->pTrigger;
+  while( p ){
+    Trigger *pTrig = (Trigger *)sqliteHashData(p);
+    if( pTrig->pTabSchema==pTab->pSchema
+     && pTrig->table
+     && 0==sqlite3StrICmp(pTrig->table, pTab->zName)
+     && (pTrig->pTabSchema!=pTmpSchema || pTrig->bReturning)
+    ){
+      pTrig->pNext = pList;
+      pList = pTrig;
+    }else if( pTrig->op==TK_RETURNING ){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+      assert( pParse->db->pVtabCtx==0 );
+#endif
+      assert( pParse->bReturning );
+      assert( &(pParse->u1.pReturning->retTrig) == pTrig );
+      pTrig->table = pTab->zName;
+      pTrig->pTabSchema = pTab->pSchema;
+      pTrig->pNext = pList;
+      pList = pTrig;
+    }
+    p = sqliteHashNext(p);
+  }
+#if 0
+  if( pList ){
+    Trigger *pX;
+    printf("Triggers for %s:", pTab->zName);
+    for(pX=pList; pX; pX=pX->pNext){
+      printf(" %s", pX->zName);
+    }
+    printf("\n");
+    fflush(stdout);
+  }
+#endif
+  return pList;
+}
+
+/*
+** This is called by the parser when it sees a CREATE TRIGGER statement
+** up to the point of the BEGIN before the trigger actions.  A Trigger
+** structure is generated based on the information available and stored
+** in pParse->pNewTrigger.  After the trigger actions have been parsed, the
+** sqlite3FinishTrigger() function is called to complete the trigger
+** construction process.
+*/
+SQLITE_PRIVATE void sqlite3BeginTrigger(
+  Parse *pParse,      /* The parse context of the CREATE TRIGGER statement */
+  Token *pName1,      /* The name of the trigger */
+  Token *pName2,      /* The name of the trigger */
+  int tr_tm,          /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
+  int op,             /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
+  IdList *pColumns,   /* column list if this is an UPDATE OF trigger */
+  SrcList *pTableName,/* The name of the table/view the trigger applies to */
+  Expr *pWhen,        /* WHEN clause */
+  int isTemp,         /* True if the TEMPORARY keyword is present */
+  int noErr           /* Suppress errors if the trigger already exists */
+){
+  Trigger *pTrigger = 0;  /* The new trigger */
+  Table *pTab;            /* Table that the trigger fires off of */
+  char *zName = 0;        /* Name of the trigger */
+  sqlite3 *db = pParse->db;  /* The database connection */
+  int iDb;                /* The database to store the trigger in */
+  Token *pName;           /* The unqualified db name */
+  DbFixer sFix;           /* State vector for the DB fixer */
+
+  assert( pName1!=0 );   /* pName1->z might be NULL, but not pName1 itself */
+  assert( pName2!=0 );
+  assert( op==TK_INSERT || op==TK_UPDATE || op==TK_DELETE );
+  assert( op>0 && op<0xff );
+  if( isTemp ){
+    /* If TEMP was specified, then the trigger name may not be qualified. */
+    if( pName2->n>0 ){
+      sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
+      goto trigger_cleanup;
+    }
+    iDb = 1;
+    pName = pName1;
+  }else{
+    /* Figure out the db that the trigger will be created in */
+    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
+    if( iDb<0 ){
+      goto trigger_cleanup;
+    }
+  }
+  if( !pTableName || db->mallocFailed ){
+    goto trigger_cleanup;
+  }
+
+  /* A long-standing parser bug is that this syntax was allowed:
+  **
+  **    CREATE TRIGGER attached.demo AFTER INSERT ON attached.tab ....
+  **                                                 ^^^^^^^^
+  **
+  ** To maintain backwards compatibility, ignore the database
+  ** name on pTableName if we are reparsing out of the schema table
+  */
+  if( db->init.busy && iDb!=1 ){
+    assert( pTableName->a[0].fg.fixedSchema==0 );
+    assert( pTableName->a[0].fg.isSubquery==0 );
+    sqlite3DbFree(db, pTableName->a[0].u4.zDatabase);
+    pTableName->a[0].u4.zDatabase = 0;
+  }
+
+  /* If the trigger name was unqualified, and the table is a temp table,
+  ** then set iDb to 1 to create the trigger in the temporary database.
+  ** If sqlite3SrcListLookup() returns 0, indicating the table does not
+  ** exist, the error is caught by the block below.
+  */
+  pTab = sqlite3SrcListLookup(pParse, pTableName);
+  if( db->init.busy==0 && pName2->n==0 && pTab
+        && pTab->pSchema==db->aDb[1].pSchema ){
+    iDb = 1;
+  }
+
+  /* Ensure the table name matches database name and that the table exists */
+  if( db->mallocFailed ) goto trigger_cleanup;
+  assert( pTableName->nSrc==1 );
+  sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName);
+  if( sqlite3FixSrcList(&sFix, pTableName) ){
+    goto trigger_cleanup;
+  }
+  pTab = sqlite3SrcListLookup(pParse, pTableName);
+  if( !pTab ){
+    /* The table does not exist. */
+    goto trigger_orphan_error;
+  }
+  if( IsVirtual(pTab) ){
+    sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables");
+    goto trigger_orphan_error;
+  }
+  if( (pTab->tabFlags & TF_Shadow)!=0 && sqlite3ReadOnlyShadowTables(db) ){
+    sqlite3ErrorMsg(pParse, "cannot create triggers on shadow tables");
+    goto trigger_orphan_error;
+  }
+
+  /* Check that the trigger name is not reserved and that no trigger of the
+  ** specified name exists */
+  zName = sqlite3NameFromToken(db, pName);
+  if( zName==0 ){
+    assert( db->mallocFailed );
+    goto trigger_cleanup;
+  }
+  if( sqlite3CheckObjectName(pParse, zName, "trigger", pTab->zName) ){
+    goto trigger_cleanup;
+  }
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  if( !IN_RENAME_OBJECT ){
+    if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash),zName) ){
+      if( !noErr ){
+        sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
+      }else{
+        assert( !db->init.busy );
+        sqlite3CodeVerifySchema(pParse, iDb);
+        VVA_ONLY( pParse->ifNotExists = 1; )
+      }
+      goto trigger_cleanup;
+    }
+  }
+
+  /* Do not create a trigger on a system table */
+  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
+    sqlite3ErrorMsg(pParse, "cannot create trigger on system table");
+    goto trigger_cleanup;
+  }
+
+  /* INSTEAD of triggers are only for views and views only support INSTEAD
+  ** of triggers.
+  */
+  if( IsView(pTab) && tr_tm!=TK_INSTEAD ){
+    sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S",
+        (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName->a);
+    goto trigger_orphan_error;
+  }
+  if( !IsView(pTab) && tr_tm==TK_INSTEAD ){
+    sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
+        " trigger on table: %S", pTableName->a);
+    goto trigger_orphan_error;
+  }
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( !IN_RENAME_OBJECT ){
+    int iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    int code = SQLITE_CREATE_TRIGGER;
+    const char *zDb = db->aDb[iTabDb].zDbSName;
+    const char *zDbTrig = isTemp ? db->aDb[1].zDbSName : zDb;
+    if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
+    if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
+      goto trigger_cleanup;
+    }
+    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){
+      goto trigger_cleanup;
+    }
+  }
+#endif
+
+  /* INSTEAD OF triggers can only appear on views and BEFORE triggers
+  ** cannot appear on views.  So we might as well translate every
+  ** INSTEAD OF trigger into a BEFORE trigger.  It simplifies code
+  ** elsewhere.
+  */
+  if (tr_tm == TK_INSTEAD){
+    tr_tm = TK_BEFORE;
+  }
+
+  /* Build the Trigger object */
+  pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger));
+  if( pTrigger==0 ) goto trigger_cleanup;
+  pTrigger->zName = zName;
+  zName = 0;
+  pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
+  pTrigger->pSchema = db->aDb[iDb].pSchema;
+  pTrigger->pTabSchema = pTab->pSchema;
+  pTrigger->op = (u8)op;
+  pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameTokenRemap(pParse, pTrigger->table, pTableName->a[0].zName);
+    pTrigger->pWhen = pWhen;
+    pWhen = 0;
+  }else{
+    pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
+  }
+  pTrigger->pColumns = pColumns;
+  pColumns = 0;
+  assert( pParse->pNewTrigger==0 );
+  pParse->pNewTrigger = pTrigger;
+
+trigger_cleanup:
+  sqlite3DbFree(db, zName);
+  sqlite3SrcListDelete(db, pTableName);
+  sqlite3IdListDelete(db, pColumns);
+  sqlite3ExprDelete(db, pWhen);
+  if( !pParse->pNewTrigger ){
+    sqlite3DeleteTrigger(db, pTrigger);
+  }else{
+    assert( pParse->pNewTrigger==pTrigger );
+  }
+  return;
+
+trigger_orphan_error:
+  if( db->init.iDb==1 ){
+    /* Ticket #3810.
+    ** Normally, whenever a table is dropped, all associated triggers are
+    ** dropped too.  But if a TEMP trigger is created on a non-TEMP table
+    ** and the table is dropped by a different database connection, the
+    ** trigger is not visible to the database connection that does the
+    ** drop so the trigger cannot be dropped.  This results in an
+    ** "orphaned trigger" - a trigger whose associated table is missing.
+    **
+    ** 2020-11-05 see also https://sqlite.org/forum/forumpost/157dc791df
+    */
+    db->init.orphanTrigger = 1;
+  }
+  goto trigger_cleanup;
+}
+
+/*
+** This routine is called after all of the trigger actions have been parsed
+** in order to complete the process of building the trigger.
+*/
+SQLITE_PRIVATE void sqlite3FinishTrigger(
+  Parse *pParse,          /* Parser context */
+  TriggerStep *pStepList, /* The triggered program */
+  Token *pAll             /* Token that describes the complete CREATE TRIGGER */
+){
+  Trigger *pTrig = pParse->pNewTrigger;   /* Trigger being finished */
+  char *zName;                            /* Name of trigger */
+  sqlite3 *db = pParse->db;               /* The database */
+  DbFixer sFix;                           /* Fixer object */
+  int iDb;                                /* Database containing the trigger */
+  Token nameToken;                        /* Trigger name for error reporting */
+
+  pParse->pNewTrigger = 0;
+  if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup;
+  zName = pTrig->zName;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
+  pTrig->step_list = pStepList;
+  while( pStepList ){
+    pStepList->pTrig = pTrig;
+    pStepList = pStepList->pNext;
+  }
+  sqlite3TokenInit(&nameToken, pTrig->zName);
+  sqlite3FixInit(&sFix, pParse, iDb, "trigger", &nameToken);
+  if( sqlite3FixTriggerStep(&sFix, pTrig->step_list)
+   || sqlite3FixExpr(&sFix, pTrig->pWhen)
+  ){
+    goto triggerfinish_cleanup;
+  }
+
+#ifndef SQLITE_OMIT_ALTERTABLE
+  if( IN_RENAME_OBJECT ){
+    assert( !db->init.busy );
+    pParse->pNewTrigger = pTrig;
+    pTrig = 0;
+  }else
+#endif
+
+  /* if we are not initializing,
+  ** build the sqlite_schema entry
+  */
+  if( !db->init.busy ){
+    Vdbe *v;
+    char *z;
+
+    /* If this is a new CREATE TABLE statement, and if shadow tables
+    ** are read-only, and the trigger makes a change to a shadow table,
+    ** then raise an error - do not allow the trigger to be created. */
+    if( sqlite3ReadOnlyShadowTables(db) ){
+      TriggerStep *pStep;
+      for(pStep=pTrig->step_list; pStep; pStep=pStep->pNext){
+        if( pStep->zTarget!=0
+         && sqlite3ShadowTableName(db, pStep->zTarget)
+        ){
+          sqlite3ErrorMsg(pParse,
+            "trigger \"%s\" may not write to shadow table \"%s\"",
+            pTrig->zName, pStep->zTarget);
+          goto triggerfinish_cleanup;
+        }
+      }
+    }
+
+    /* Make an entry in the sqlite_schema table */
+    v = sqlite3GetVdbe(pParse);
+    if( v==0 ) goto triggerfinish_cleanup;
+    sqlite3BeginWriteOperation(pParse, 0, iDb);
+    z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n);
+    testcase( z==0 );
+    sqlite3NestedParse(pParse,
+       "INSERT INTO %Q." LEGACY_SCHEMA_TABLE
+       " VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')",
+       db->aDb[iDb].zDbSName, zName,
+       pTrig->table, z);
+    sqlite3DbFree(db, z);
+    sqlite3ChangeCookie(pParse, iDb);
+    sqlite3VdbeAddParseSchemaOp(v, iDb,
+        sqlite3MPrintf(db, "type='trigger' AND name='%q'", zName), 0);
+  }
+
+  if( db->init.busy ){
+    Trigger *pLink = pTrig;
+    Hash *pHash = &db->aDb[iDb].pSchema->trigHash;
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    assert( pLink!=0 );
+    pTrig = sqlite3HashInsert(pHash, zName, pTrig);
+    if( pTrig ){
+      sqlite3OomFault(db);
+    }else if( pLink->pSchema==pLink->pTabSchema ){
+      Table *pTab;
+      pTab = sqlite3HashFind(&pLink->pTabSchema->tblHash, pLink->table);
+      assert( pTab!=0 );
+      pLink->pNext = pTab->pTrigger;
+      pTab->pTrigger = pLink;
+    }
+  }
+
+triggerfinish_cleanup:
+  sqlite3DeleteTrigger(db, pTrig);
+  assert( IN_RENAME_OBJECT || !pParse->pNewTrigger );
+  sqlite3DeleteTriggerStep(db, pStepList);
+}
+
+/*
+** Duplicate a range of text from an SQL statement, then convert all
+** whitespace characters into ordinary space characters.
+*/
+static char *triggerSpanDup(sqlite3 *db, const char *zStart, const char *zEnd){
+  char *z = sqlite3DbSpanDup(db, zStart, zEnd);
+  int i;
+  if( z ) for(i=0; z[i]; i++) if( sqlite3Isspace(z[i]) ) z[i] = ' ';
+  return z;
+}
+
+/*
+** Turn a SELECT statement (that the pSelect parameter points to) into
+** a trigger step.  Return a pointer to a TriggerStep structure.
+**
+** The parser calls this routine when it finds a SELECT statement in
+** body of a TRIGGER.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerSelectStep(
+  sqlite3 *db,                /* Database connection */
+  Select *pSelect,            /* The SELECT statement */
+  const char *zStart,         /* Start of SQL text */
+  const char *zEnd            /* End of SQL text */
+){
+  TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
+  if( pTriggerStep==0 ) {
+    sqlite3SelectDelete(db, pSelect);
+    return 0;
+  }
+  pTriggerStep->op = TK_SELECT;
+  pTriggerStep->pSelect = pSelect;
+  pTriggerStep->orconf = OE_Default;
+  pTriggerStep->zSpan = triggerSpanDup(db, zStart, zEnd);
+  return pTriggerStep;
+}
+
+/*
+** Allocate space to hold a new trigger step.  The allocated space
+** holds both the TriggerStep object and the TriggerStep.target.z string.
+**
+** If an OOM error occurs, NULL is returned and db->mallocFailed is set.
+*/
+static TriggerStep *triggerStepAllocate(
+  Parse *pParse,              /* Parser context */
+  u8 op,                      /* Trigger opcode */
+  Token *pName,               /* The target name */
+  const char *zStart,         /* Start of SQL text */
+  const char *zEnd            /* End of SQL text */
+){
+  sqlite3 *db = pParse->db;
+  TriggerStep *pTriggerStep;
+
+  if( pParse->nErr ) return 0;
+  pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep) + pName->n + 1);
+  if( pTriggerStep ){
+    char *z = (char*)&pTriggerStep[1];
+    memcpy(z, pName->z, pName->n);
+    sqlite3Dequote(z);
+    pTriggerStep->zTarget = z;
+    pTriggerStep->op = op;
+    pTriggerStep->zSpan = triggerSpanDup(db, zStart, zEnd);
+    if( IN_RENAME_OBJECT ){
+      sqlite3RenameTokenMap(pParse, pTriggerStep->zTarget, pName);
+    }
+  }
+  return pTriggerStep;
+}
+
+/*
+** Build a trigger step out of an INSERT statement.  Return a pointer
+** to the new trigger step.
+**
+** The parser calls this routine when it sees an INSERT inside the
+** body of a trigger.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerInsertStep(
+  Parse *pParse,      /* Parser */
+  Token *pTableName,  /* Name of the table into which we insert */
+  IdList *pColumn,    /* List of columns in pTableName to insert into */
+  Select *pSelect,    /* A SELECT statement that supplies values */
+  u8 orconf,          /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
+  Upsert *pUpsert,    /* ON CONFLICT clauses for upsert */
+  const char *zStart, /* Start of SQL text */
+  const char *zEnd    /* End of SQL text */
+){
+  sqlite3 *db = pParse->db;
+  TriggerStep *pTriggerStep;
+
+  assert(pSelect != 0 || db->mallocFailed);
+
+  pTriggerStep = triggerStepAllocate(pParse, TK_INSERT, pTableName,zStart,zEnd);
+  if( pTriggerStep ){
+    if( IN_RENAME_OBJECT ){
+      pTriggerStep->pSelect = pSelect;
+      pSelect = 0;
+    }else{
+      pTriggerStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
+    }
+    pTriggerStep->pIdList = pColumn;
+    pTriggerStep->pUpsert = pUpsert;
+    pTriggerStep->orconf = orconf;
+    if( pUpsert ){
+      sqlite3HasExplicitNulls(pParse, pUpsert->pUpsertTarget);
+    }
+  }else{
+    testcase( pColumn );
+    sqlite3IdListDelete(db, pColumn);
+    testcase( pUpsert );
+    sqlite3UpsertDelete(db, pUpsert);
+  }
+  sqlite3SelectDelete(db, pSelect);
+
+  return pTriggerStep;
+}
+
+/*
+** Construct a trigger step that implements an UPDATE statement and return
+** a pointer to that trigger step.  The parser calls this routine when it
+** sees an UPDATE statement inside the body of a CREATE TRIGGER.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerUpdateStep(
+  Parse *pParse,          /* Parser */
+  Token *pTableName,   /* Name of the table to be updated */
+  SrcList *pFrom,      /* FROM clause for an UPDATE-FROM, or NULL */
+  ExprList *pEList,    /* The SET clause: list of column and new values */
+  Expr *pWhere,        /* The WHERE clause */
+  u8 orconf,           /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
+  const char *zStart,  /* Start of SQL text */
+  const char *zEnd     /* End of SQL text */
+){
+  sqlite3 *db = pParse->db;
+  TriggerStep *pTriggerStep;
+
+  pTriggerStep = triggerStepAllocate(pParse, TK_UPDATE, pTableName,zStart,zEnd);
+  if( pTriggerStep ){
+    if( IN_RENAME_OBJECT ){
+      pTriggerStep->pExprList = pEList;
+      pTriggerStep->pWhere = pWhere;
+      pTriggerStep->pFrom = pFrom;
+      pEList = 0;
+      pWhere = 0;
+      pFrom = 0;
+    }else{
+      pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE);
+      pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
+      pTriggerStep->pFrom = sqlite3SrcListDup(db, pFrom, EXPRDUP_REDUCE);
+    }
+    pTriggerStep->orconf = orconf;
+  }
+  sqlite3ExprListDelete(db, pEList);
+  sqlite3ExprDelete(db, pWhere);
+  sqlite3SrcListDelete(db, pFrom);
+  return pTriggerStep;
+}
+
+/*
+** Construct a trigger step that implements a DELETE statement and return
+** a pointer to that trigger step.  The parser calls this routine when it
+** sees a DELETE statement inside the body of a CREATE TRIGGER.
+*/
+SQLITE_PRIVATE TriggerStep *sqlite3TriggerDeleteStep(
+  Parse *pParse,          /* Parser */
+  Token *pTableName,      /* The table from which rows are deleted */
+  Expr *pWhere,           /* The WHERE clause */
+  const char *zStart,     /* Start of SQL text */
+  const char *zEnd        /* End of SQL text */
+){
+  sqlite3 *db = pParse->db;
+  TriggerStep *pTriggerStep;
+
+  pTriggerStep = triggerStepAllocate(pParse, TK_DELETE, pTableName,zStart,zEnd);
+  if( pTriggerStep ){
+    if( IN_RENAME_OBJECT ){
+      pTriggerStep->pWhere = pWhere;
+      pWhere = 0;
+    }else{
+      pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
+    }
+    pTriggerStep->orconf = OE_Default;
+  }
+  sqlite3ExprDelete(db, pWhere);
+  return pTriggerStep;
+}
+
+/*
+** Recursively delete a Trigger structure
+*/
+SQLITE_PRIVATE void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){
+  if( pTrigger==0 || pTrigger->bReturning ) return;
+  sqlite3DeleteTriggerStep(db, pTrigger->step_list);
+  sqlite3DbFree(db, pTrigger->zName);
+  sqlite3DbFree(db, pTrigger->table);
+  sqlite3ExprDelete(db, pTrigger->pWhen);
+  sqlite3IdListDelete(db, pTrigger->pColumns);
+  sqlite3DbFree(db, pTrigger);
+}
+
+/*
+** This function is called to drop a trigger from the database schema.
+**
+** This may be called directly from the parser and therefore identifies
+** the trigger by name.  The sqlite3DropTriggerPtr() routine does the
+** same job as this routine except it takes a pointer to the trigger
+** instead of the trigger name.
+**/
+SQLITE_PRIVATE void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
+  Trigger *pTrigger = 0;
+  int i;
+  const char *zDb;
+  const char *zName;
+  sqlite3 *db = pParse->db;
+
+  if( db->mallocFailed ) goto drop_trigger_cleanup;
+  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+    goto drop_trigger_cleanup;
+  }
+
+  assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 && pName->a[0].fg.isSubquery==0 );
+  zDb = pName->a[0].u4.zDatabase;
+  zName = pName->a[0].zName;
+  assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );
+  for(i=OMIT_TEMPDB; i<db->nDb; i++){
+    int j = (i<2) ? i^1 : i;  /* Search TEMP before MAIN */
+    if( zDb && sqlite3DbIsNamed(db, j, zDb)==0 ) continue;
+    assert( sqlite3SchemaMutexHeld(db, j, 0) );
+    pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName);
+    if( pTrigger ) break;
+  }
+  if( !pTrigger ){
+    if( !noErr ){
+      sqlite3ErrorMsg(pParse, "no such trigger: %S", pName->a);
+    }else{
+      sqlite3CodeVerifyNamedSchema(pParse, zDb);
+    }
+    pParse->checkSchema = 1;
+    goto drop_trigger_cleanup;
+  }
+  sqlite3DropTriggerPtr(pParse, pTrigger);
+
+drop_trigger_cleanup:
+  sqlite3SrcListDelete(db, pName);
+}
+
+/*
+** Return a pointer to the Table structure for the table that a trigger
+** is set on.
+*/
+static Table *tableOfTrigger(Trigger *pTrigger){
+  return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table);
+}
+
+
+/*
+** Drop a trigger given a pointer to that trigger.
+*/
+SQLITE_PRIVATE void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
+  Table   *pTable;
+  Vdbe *v;
+  sqlite3 *db = pParse->db;
+  int iDb;
+
+  iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
+  assert( iDb>=0 && iDb<db->nDb );
+  pTable = tableOfTrigger(pTrigger);
+  assert( (pTable && pTable->pSchema==pTrigger->pSchema) || iDb==1 );
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  if( pTable ){
+    int code = SQLITE_DROP_TRIGGER;
+    const char *zDb = db->aDb[iDb].zDbSName;
+    const char *zTab = SCHEMA_TABLE(iDb);
+    if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
+    if( sqlite3AuthCheck(pParse, code, pTrigger->zName, pTable->zName, zDb) ||
+      sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
+      return;
+    }
+  }
+#endif
+
+  /* Generate code to destroy the database record of the trigger.
+  */
+  if( (v = sqlite3GetVdbe(pParse))!=0 ){
+    sqlite3NestedParse(pParse,
+       "DELETE FROM %Q." LEGACY_SCHEMA_TABLE " WHERE name=%Q AND type='trigger'",
+       db->aDb[iDb].zDbSName, pTrigger->zName
+    );
+    sqlite3ChangeCookie(pParse, iDb);
+    sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0);
+  }
+}
+
+/*
+** Remove a trigger from the hash tables of the sqlite* pointer.
+*/
+SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
+  Trigger *pTrigger;
+  Hash *pHash;
+
+  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+  pHash = &(db->aDb[iDb].pSchema->trigHash);
+  pTrigger = sqlite3HashInsert(pHash, zName, 0);
+  if( ALWAYS(pTrigger) ){
+    if( pTrigger->pSchema==pTrigger->pTabSchema ){
+      Table *pTab = tableOfTrigger(pTrigger);
+      if( pTab ){
+        Trigger **pp;
+        for(pp=&pTab->pTrigger; *pp; pp=&((*pp)->pNext)){
+          if( *pp==pTrigger ){
+            *pp = (*pp)->pNext;
+            break;
+          }
+        }
+      }
+    }
+    sqlite3DeleteTrigger(db, pTrigger);
+    db->mDbFlags |= DBFLAG_SchemaChange;
+  }
+}
+
+/*
+** pEList is the SET clause of an UPDATE statement.  Each entry
+** in pEList is of the format <id>=<expr>.  If any of the entries
+** in pEList have an <id> which matches an identifier in pIdList,
+** then return TRUE.  If pIdList==NULL, then it is considered a
+** wildcard that matches anything.  Likewise if pEList==NULL then
+** it matches anything so always return true.  Return false only
+** if there is no match.
+*/
+static int checkColumnOverlap(IdList *pIdList, ExprList *pEList){
+  int e;
+  if( pIdList==0 || NEVER(pEList==0) ) return 1;
+  for(e=0; e<pEList->nExpr; e++){
+    if( sqlite3IdListIndex(pIdList, pEList->a[e].zEName)>=0 ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Return true if any TEMP triggers exist
+*/
+static int tempTriggersExist(sqlite3 *db){
+  if( NEVER(db->aDb[1].pSchema==0) ) return 0;
+  if( sqliteHashFirst(&db->aDb[1].pSchema->trigHash)==0 ) return 0;
+  return 1;
+}
+
+/*
+** Return a list of all triggers on table pTab if there exists at least
+** one trigger that must be fired when an operation of type 'op' is
+** performed on the table, and, if that operation is an UPDATE, if at
+** least one of the columns in pChanges is being modified.
+*/
+static SQLITE_NOINLINE Trigger *triggersReallyExist(
+  Parse *pParse,          /* Parse context */
+  Table *pTab,            /* The table the contains the triggers */
+  int op,                 /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
+  ExprList *pChanges,     /* Columns that change in an UPDATE statement */
+  int *pMask              /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
+){
+  int mask = 0;
+  Trigger *pList = 0;
+  Trigger *p;
+
+  pList = sqlite3TriggerList(pParse, pTab);
+  assert( pList==0 || IsVirtual(pTab)==0
+           || (pList->bReturning && pList->pNext==0) );
+  if( pList!=0 ){
+    p = pList;
+    if( (pParse->db->flags & SQLITE_EnableTrigger)==0
+     && pTab->pTrigger!=0
+    ){
+      /* The SQLITE_DBCONFIG_ENABLE_TRIGGER setting is off.  That means that
+      ** only TEMP triggers are allowed.  Truncate the pList so that it
+      ** includes only TEMP triggers */
+      if( pList==pTab->pTrigger ){
+        pList = 0;
+        goto exit_triggers_exist;
+      }
+      while( ALWAYS(p->pNext) && p->pNext!=pTab->pTrigger ) p = p->pNext;
+      p->pNext = 0;
+      p = pList;
+    }
+    do{
+      if( p->op==op && checkColumnOverlap(p->pColumns, pChanges) ){
+        mask |= p->tr_tm;
+      }else if( p->op==TK_RETURNING ){
+        /* The first time a RETURNING trigger is seen, the "op" value tells
+        ** us what time of trigger it should be. */
+        assert( sqlite3IsToplevel(pParse) );
+        p->op = op;
+        if( IsVirtual(pTab) ){
+          if( op!=TK_INSERT ){
+            sqlite3ErrorMsg(pParse,
+              "%s RETURNING is not available on virtual tables",
+              op==TK_DELETE ? "DELETE" : "UPDATE");
+          }
+          p->tr_tm = TRIGGER_BEFORE;
+        }else{
+          p->tr_tm = TRIGGER_AFTER;
+        }
+        mask |= p->tr_tm;
+      }else if( p->bReturning && p->op==TK_INSERT && op==TK_UPDATE
+                && sqlite3IsToplevel(pParse) ){
+        /* Also fire a RETURNING trigger for an UPSERT */
+        mask |= p->tr_tm;
+      }
+      p = p->pNext;
+    }while( p );
+  }
+exit_triggers_exist:
+  if( pMask ){
+    *pMask = mask;
+  }
+  return (mask ? pList : 0);
+}
+SQLITE_PRIVATE Trigger *sqlite3TriggersExist(
+  Parse *pParse,          /* Parse context */
+  Table *pTab,            /* The table the contains the triggers */
+  int op,                 /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
+  ExprList *pChanges,     /* Columns that change in an UPDATE statement */
+  int *pMask              /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
+){
+  assert( pTab!=0 );
+  if( (pTab->pTrigger==0 && !tempTriggersExist(pParse->db))
+   || pParse->disableTriggers
+  ){
+    if( pMask ) *pMask = 0;
+    return 0;
+  }
+  return triggersReallyExist(pParse,pTab,op,pChanges,pMask);
+}
+
+/*
+** Convert the pStep->zTarget string into a SrcList and return a pointer
+** to that SrcList.
+**
+** This routine adds a specific database name, if needed, to the target when
+** forming the SrcList.  This prevents a trigger in one database from
+** referring to a target in another database.  An exception is when the
+** trigger is in TEMP in which case it can refer to any other database it
+** wants.
+*/
+SQLITE_PRIVATE SrcList *sqlite3TriggerStepSrc(
+  Parse *pParse,       /* The parsing context */
+  TriggerStep *pStep   /* The trigger containing the target token */
+){
+  sqlite3 *db = pParse->db;
+  SrcList *pSrc;                  /* SrcList to be returned */
+  char *zName = sqlite3DbStrDup(db, pStep->zTarget);
+  pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
+  assert( pSrc==0 || pSrc->nSrc==1 );
+  assert( zName || pSrc==0 );
+  if( pSrc ){
+    Schema *pSchema = pStep->pTrig->pSchema;
+    pSrc->a[0].zName = zName;
+    if( pSchema!=db->aDb[1].pSchema ){
+      assert( pSrc->a[0].fg.fixedSchema || pSrc->a[0].u4.zDatabase==0 );
+      pSrc->a[0].u4.pSchema = pSchema;
+      pSrc->a[0].fg.fixedSchema = 1;
+    }
+    if( pStep->pFrom ){
+      SrcList *pDup = sqlite3SrcListDup(db, pStep->pFrom, 0);
+      if( pDup && pDup->nSrc>1 && !IN_RENAME_OBJECT ){
+        Select *pSubquery;
+        Token as;
+        pSubquery = sqlite3SelectNew(pParse,0,pDup,0,0,0,0,SF_NestedFrom,0);
+        as.n = 0;
+        as.z = 0;
+        pDup = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&as,pSubquery,0);
+      }
+      pSrc = sqlite3SrcListAppendList(pParse, pSrc, pDup);
+    }
+  }else{
+    sqlite3DbFree(db, zName);
+  }
+  return pSrc;
+}
+
+/*
+** Return true if the pExpr term from the RETURNING clause argument
+** list is of the form "*".  Raise an error if the terms if of the
+** form "table.*".
+*/
+static int isAsteriskTerm(
+  Parse *pParse,      /* Parsing context */
+  Expr *pTerm         /* A term in the RETURNING clause */
+){
+  assert( pTerm!=0 );
+  if( pTerm->op==TK_ASTERISK ) return 1;
+  if( pTerm->op!=TK_DOT ) return 0;
+  assert( pTerm->pRight!=0 );
+  assert( pTerm->pLeft!=0 );
+  if( pTerm->pRight->op!=TK_ASTERISK ) return 0;
+  sqlite3ErrorMsg(pParse, "RETURNING may not use \"TABLE.*\" wildcards");
+  return 1;
+}
+
+/* The input list pList is the list of result set terms from a RETURNING
+** clause.  The table that we are returning from is pTab.
+**
+** This routine makes a copy of the pList, and at the same time expands
+** any "*" wildcards to be the complete set of columns from pTab.
+*/
+static ExprList *sqlite3ExpandReturning(
+  Parse *pParse,        /* Parsing context */
+  ExprList *pList,      /* The arguments to RETURNING */
+  Table *pTab           /* The table being updated */
+){
+  ExprList *pNew = 0;
+  sqlite3 *db = pParse->db;
+  int i;
+
+  for(i=0; i<pList->nExpr; i++){
+    Expr *pOldExpr = pList->a[i].pExpr;
+    if( NEVER(pOldExpr==0) ) continue;
+    if( isAsteriskTerm(pParse, pOldExpr) ){
+      int jj;
+      for(jj=0; jj<pTab->nCol; jj++){
+        Expr *pNewExpr;
+        if( IsHiddenColumn(pTab->aCol+jj) ) continue;
+        pNewExpr = sqlite3Expr(db, TK_ID, pTab->aCol[jj].zCnName);
+        pNew = sqlite3ExprListAppend(pParse, pNew, pNewExpr);
+        if( !db->mallocFailed ){
+          struct ExprList_item *pItem = &pNew->a[pNew->nExpr-1];
+          pItem->zEName = sqlite3DbStrDup(db, pTab->aCol[jj].zCnName);
+          pItem->fg.eEName = ENAME_NAME;
+        }
+      }
+    }else{
+      Expr *pNewExpr = sqlite3ExprDup(db, pOldExpr, 0);
+      pNew = sqlite3ExprListAppend(pParse, pNew, pNewExpr);
+      if( !db->mallocFailed && ALWAYS(pList->a[i].zEName!=0) ){
+        struct ExprList_item *pItem = &pNew->a[pNew->nExpr-1];
+        pItem->zEName = sqlite3DbStrDup(db, pList->a[i].zEName);
+        pItem->fg.eEName = pList->a[i].fg.eEName;
+      }
+    }
+  }
+  return pNew;
+}
+
+/* If the Expr node is a subquery or an EXISTS operator or an IN operator that
+** uses a subquery, and if the subquery is SF_Correlated, then mark the
+** expression as EP_VarSelect.
+*/
+static int sqlite3ReturningSubqueryVarSelect(Walker *NotUsed, Expr *pExpr){
+  UNUSED_PARAMETER(NotUsed);
+  if( ExprUseXSelect(pExpr)
+   && (pExpr->x.pSelect->selFlags & SF_Correlated)!=0
+  ){
+    testcase( ExprHasProperty(pExpr, EP_VarSelect) );
+    ExprSetProperty(pExpr, EP_VarSelect);
+  }
+  return WRC_Continue;
+}
+
+
+/*
+** If the SELECT references the table pWalker->u.pTab, then do two things:
+**
+**    (1) Mark the SELECT as as SF_Correlated.
+**    (2) Set pWalker->eCode to non-zero so that the caller will know
+**        that (1) has happened.
+*/
+static int sqlite3ReturningSubqueryCorrelated(Walker *pWalker, Select *pSelect){
+  int i;
+  SrcList *pSrc;
+  assert( pSelect!=0 );
+  pSrc = pSelect->pSrc;
+  assert( pSrc!=0 );
+  for(i=0; i<pSrc->nSrc; i++){
+    if( pSrc->a[i].pSTab==pWalker->u.pTab ){
+      testcase( pSelect->selFlags & SF_Correlated );
+      pSelect->selFlags |= SF_Correlated;
+      pWalker->eCode = 1;
+      break;
+    }
+  }
+  return WRC_Continue;
+}
+
+/*
+** Scan the expression list that is the argument to RETURNING looking
+** for subqueries that depend on the table which is being modified in the
+** statement that is hosting the RETURNING clause (pTab).  Mark all such
+** subqueries as SF_Correlated.  If the subqueries are part of an
+** expression, mark the expression as EP_VarSelect.
+**
+** https://sqlite.org/forum/forumpost/2c83569ce8945d39
+*/
+static void sqlite3ProcessReturningSubqueries(
+  ExprList *pEList,
+  Table *pTab
+){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.xSelectCallback = sqlite3ReturningSubqueryCorrelated;
+  w.u.pTab = pTab;
+  sqlite3WalkExprList(&w, pEList);
+  if( w.eCode ){
+    w.xExprCallback = sqlite3ReturningSubqueryVarSelect;
+    w.xSelectCallback = sqlite3SelectWalkNoop;
+    sqlite3WalkExprList(&w, pEList);
+  }
+}
+
+/*
+** Generate code for the RETURNING trigger.  Unlike other triggers
+** that invoke a subprogram in the bytecode, the code for RETURNING
+** is generated in-line.
+*/
+static void codeReturningTrigger(
+  Parse *pParse,       /* Parse context */
+  Trigger *pTrigger,   /* The trigger step that defines the RETURNING */
+  Table *pTab,         /* The table to code triggers from */
+  int regIn            /* The first in an array of registers */
+){
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
+  ExprList *pNew;
+  Returning *pReturning;
+  Select sSelect;
+  SrcList sFrom;
+
+  assert( v!=0 );
+  if( !pParse->bReturning ){
+    /* This RETURNING trigger must be for a different statement as
+    ** this statement lacks a RETURNING clause. */
+    return;
+  }
+  assert( db->pParse==pParse );
+  pReturning = pParse->u1.pReturning;
+  if( pTrigger != &(pReturning->retTrig) ){
+    /* This RETURNING trigger is for a different statement */
+    return;
+  }
+  memset(&sSelect, 0, sizeof(sSelect));
+  memset(&sFrom, 0, sizeof(sFrom));
+  sSelect.pEList = sqlite3ExprListDup(db, pReturning->pReturnEL, 0);
+  sSelect.pSrc = &sFrom;
+  sFrom.nSrc = 1;
+  sFrom.a[0].pSTab = pTab;
+  sFrom.a[0].zName = pTab->zName; /* tag-20240424-1 */
+  sFrom.a[0].iCursor = -1;
+  sqlite3SelectPrep(pParse, &sSelect, 0);
+  if( pParse->nErr==0 ){
+    assert( db->mallocFailed==0 );
+    sqlite3GenerateColumnNames(pParse, &sSelect);
+  }
+  sqlite3ExprListDelete(db, sSelect.pEList);
+  pNew = sqlite3ExpandReturning(pParse, pReturning->pReturnEL, pTab);
+  if( pParse->nErr==0 ){
+    NameContext sNC;
+    memset(&sNC, 0, sizeof(sNC));
+    if( pReturning->nRetCol==0 ){
+      pReturning->nRetCol = pNew->nExpr;
+      pReturning->iRetCur = pParse->nTab++;
+    }
+    sNC.pParse = pParse;
+    sNC.uNC.iBaseReg = regIn;
+    sNC.ncFlags = NC_UBaseReg;
+    pParse->eTriggerOp = pTrigger->op;
+    pParse->pTriggerTab = pTab;
+    if( sqlite3ResolveExprListNames(&sNC, pNew)==SQLITE_OK
+     && ALWAYS(!db->mallocFailed)
+    ){
+      int i;
+      int nCol = pNew->nExpr;
+      int reg = pParse->nMem+1;
+      sqlite3ProcessReturningSubqueries(pNew, pTab);
+      pParse->nMem += nCol+2;
+      pReturning->iRetReg = reg;
+      for(i=0; i<nCol; i++){
+        Expr *pCol = pNew->a[i].pExpr;
+        assert( pCol!=0 ); /* Due to !db->mallocFailed ~9 lines above */
+        sqlite3ExprCodeFactorable(pParse, pCol, reg+i);
+        if( sqlite3ExprAffinity(pCol)==SQLITE_AFF_REAL ){
+          sqlite3VdbeAddOp1(v, OP_RealAffinity, reg+i);
+        }
+      }
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, reg, i, reg+i);
+      sqlite3VdbeAddOp2(v, OP_NewRowid, pReturning->iRetCur, reg+i+1);
+      sqlite3VdbeAddOp3(v, OP_Insert, pReturning->iRetCur, reg+i, reg+i+1);
+    }
+  }
+  sqlite3ExprListDelete(db, pNew);
+  pParse->eTriggerOp = 0;
+  pParse->pTriggerTab = 0;
+}
+
+
+
+/*
+** Generate VDBE code for the statements inside the body of a single
+** trigger.
+*/
+static int codeTriggerProgram(
+  Parse *pParse,            /* The parser context */
+  TriggerStep *pStepList,   /* List of statements inside the trigger body */
+  int orconf                /* Conflict algorithm. (OE_Abort, etc) */
+){
+  TriggerStep *pStep;
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
+
+  assert( pParse->pTriggerTab && pParse->pToplevel );
+  assert( pStepList );
+  assert( v!=0 );
+  for(pStep=pStepList; pStep; pStep=pStep->pNext){
+    /* Figure out the ON CONFLICT policy that will be used for this step
+    ** of the trigger program. If the statement that caused this trigger
+    ** to fire had an explicit ON CONFLICT, then use it. Otherwise, use
+    ** the ON CONFLICT policy that was specified as part of the trigger
+    ** step statement. Example:
+    **
+    **   CREATE TRIGGER AFTER INSERT ON t1 BEGIN;
+    **     INSERT OR REPLACE INTO t2 VALUES(new.a, new.b);
+    **   END;
+    **
+    **   INSERT INTO t1 ... ;            -- insert into t2 uses REPLACE policy
+    **   INSERT OR IGNORE INTO t1 ... ;  -- insert into t2 uses IGNORE policy
+    */
+    pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf;
+    assert( pParse->okConstFactor==0 );
+
+#ifndef SQLITE_OMIT_TRACE
+    if( pStep->zSpan ){
+      sqlite3VdbeAddOp4(v, OP_Trace, 0x7fffffff, 1, 0,
+                        sqlite3MPrintf(db, "-- %s", pStep->zSpan),
+                        P4_DYNAMIC);
+    }
+#endif
+
+    switch( pStep->op ){
+      case TK_UPDATE: {
+        sqlite3Update(pParse,
+          sqlite3TriggerStepSrc(pParse, pStep),
+          sqlite3ExprListDup(db, pStep->pExprList, 0),
+          sqlite3ExprDup(db, pStep->pWhere, 0),
+          pParse->eOrconf, 0, 0, 0
+        );
+        sqlite3VdbeAddOp0(v, OP_ResetCount);
+        break;
+      }
+      case TK_INSERT: {
+        sqlite3Insert(pParse,
+          sqlite3TriggerStepSrc(pParse, pStep),
+          sqlite3SelectDup(db, pStep->pSelect, 0),
+          sqlite3IdListDup(db, pStep->pIdList),
+          pParse->eOrconf,
+          sqlite3UpsertDup(db, pStep->pUpsert)
+        );
+        sqlite3VdbeAddOp0(v, OP_ResetCount);
+        break;
+      }
+      case TK_DELETE: {
+        sqlite3DeleteFrom(pParse,
+          sqlite3TriggerStepSrc(pParse, pStep),
+          sqlite3ExprDup(db, pStep->pWhere, 0), 0, 0
+        );
+        sqlite3VdbeAddOp0(v, OP_ResetCount);
+        break;
+      }
+      default: assert( pStep->op==TK_SELECT ); {
+        SelectDest sDest;
+        Select *pSelect = sqlite3SelectDup(db, pStep->pSelect, 0);
+        sqlite3SelectDestInit(&sDest, SRT_Discard, 0);
+        sqlite3Select(pParse, pSelect, &sDest);
+        sqlite3SelectDelete(db, pSelect);
+        break;
+      }
+    }
+  }
+
+  return 0;
+}
+
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+/*
+** This function is used to add VdbeComment() annotations to a VDBE
+** program. It is not used in production code, only for debugging.
+*/
+static const char *onErrorText(int onError){
+  switch( onError ){
+    case OE_Abort:    return "abort";
+    case OE_Rollback: return "rollback";
+    case OE_Fail:     return "fail";
+    case OE_Replace:  return "replace";
+    case OE_Ignore:   return "ignore";
+    case OE_Default:  return "default";
+  }
+  return "n/a";
+}
+#endif
+
+/*
+** Parse context structure pFrom has just been used to create a sub-vdbe
+** (trigger program). If an error has occurred, transfer error information
+** from pFrom to pTo.
+*/
+static void transferParseError(Parse *pTo, Parse *pFrom){
+  assert( pFrom->zErrMsg==0 || pFrom->nErr );
+  assert( pTo->zErrMsg==0 || pTo->nErr );
+  if( pTo->nErr==0 ){
+    pTo->zErrMsg = pFrom->zErrMsg;
+    pTo->nErr = pFrom->nErr;
+    pTo->rc = pFrom->rc;
+  }else{
+    sqlite3DbFree(pFrom->db, pFrom->zErrMsg);
+  }
+}
+
+/*
+** Create and populate a new TriggerPrg object with a sub-program
+** implementing trigger pTrigger with ON CONFLICT policy orconf.
+*/
+static TriggerPrg *codeRowTrigger(
+  Parse *pParse,       /* Current parse context */
+  Trigger *pTrigger,   /* Trigger to code */
+  Table *pTab,         /* The table pTrigger is attached to */
+  int orconf           /* ON CONFLICT policy to code trigger program with */
+){
+  Parse *pTop = sqlite3ParseToplevel(pParse);
+  sqlite3 *db = pParse->db;   /* Database handle */
+  TriggerPrg *pPrg;           /* Value to return */
+  Expr *pWhen = 0;            /* Duplicate of trigger WHEN expression */
+  Vdbe *v;                    /* Temporary VM */
+  NameContext sNC;            /* Name context for sub-vdbe */
+  SubProgram *pProgram = 0;   /* Sub-vdbe for trigger program */
+  int iEndTrigger = 0;        /* Label to jump to if WHEN is false */
+  Parse sSubParse;            /* Parse context for sub-vdbe */
+
+  assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
+  assert( pTop->pVdbe );
+
+  /* Allocate the TriggerPrg and SubProgram objects. To ensure that they
+  ** are freed if an error occurs, link them into the Parse.pTriggerPrg
+  ** list of the top-level Parse object sooner rather than later.  */
+  pPrg = sqlite3DbMallocZero(db, sizeof(TriggerPrg));
+  if( !pPrg ) return 0;
+  pPrg->pNext = pTop->pTriggerPrg;
+  pTop->pTriggerPrg = pPrg;
+  pPrg->pProgram = pProgram = sqlite3DbMallocZero(db, sizeof(SubProgram));
+  if( !pProgram ) return 0;
+  sqlite3VdbeLinkSubProgram(pTop->pVdbe, pProgram);
+  pPrg->pTrigger = pTrigger;
+  pPrg->orconf = orconf;
+  pPrg->aColmask[0] = 0xffffffff;
+  pPrg->aColmask[1] = 0xffffffff;
+
+  /* Allocate and populate a new Parse context to use for coding the
+  ** trigger sub-program.  */
+  sqlite3ParseObjectInit(&sSubParse, db);
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = &sSubParse;
+  sSubParse.pTriggerTab = pTab;
+  sSubParse.pToplevel = pTop;
+  sSubParse.zAuthContext = pTrigger->zName;
+  sSubParse.eTriggerOp = pTrigger->op;
+  sSubParse.nQueryLoop = pParse->nQueryLoop;
+  sSubParse.prepFlags = pParse->prepFlags;
+
+  v = sqlite3GetVdbe(&sSubParse);
+  if( v ){
+    VdbeComment((v, "Start: %s.%s (%s %s%s%s ON %s)",
+      pTrigger->zName, onErrorText(orconf),
+      (pTrigger->tr_tm==TRIGGER_BEFORE ? "BEFORE" : "AFTER"),
+        (pTrigger->op==TK_UPDATE ? "UPDATE" : ""),
+        (pTrigger->op==TK_INSERT ? "INSERT" : ""),
+        (pTrigger->op==TK_DELETE ? "DELETE" : ""),
+      pTab->zName
+    ));
+#ifndef SQLITE_OMIT_TRACE
+    if( pTrigger->zName ){
+      sqlite3VdbeChangeP4(v, -1,
+        sqlite3MPrintf(db, "-- TRIGGER %s", pTrigger->zName), P4_DYNAMIC
+      );
+    }
+#endif
+
+    /* If one was specified, code the WHEN clause. If it evaluates to false
+    ** (or NULL) the sub-vdbe is immediately halted by jumping to the
+    ** OP_Halt inserted at the end of the program.  */
+    if( pTrigger->pWhen ){
+      pWhen = sqlite3ExprDup(db, pTrigger->pWhen, 0);
+      if( db->mallocFailed==0
+       && SQLITE_OK==sqlite3ResolveExprNames(&sNC, pWhen)
+      ){
+        iEndTrigger = sqlite3VdbeMakeLabel(&sSubParse);
+        sqlite3ExprIfFalse(&sSubParse, pWhen, iEndTrigger, SQLITE_JUMPIFNULL);
+      }
+      sqlite3ExprDelete(db, pWhen);
+    }
+
+    /* Code the trigger program into the sub-vdbe. */
+    codeTriggerProgram(&sSubParse, pTrigger->step_list, orconf);
+
+    /* Insert an OP_Halt at the end of the sub-program. */
+    if( iEndTrigger ){
+      sqlite3VdbeResolveLabel(v, iEndTrigger);
+    }
+    sqlite3VdbeAddOp0(v, OP_Halt);
+    VdbeComment((v, "End: %s.%s", pTrigger->zName, onErrorText(orconf)));
+    transferParseError(pParse, &sSubParse);
+
+    if( pParse->nErr==0 ){
+      assert( db->mallocFailed==0 );
+      pProgram->aOp = sqlite3VdbeTakeOpArray(v, &pProgram->nOp, &pTop->nMaxArg);
+    }
+    pProgram->nMem = sSubParse.nMem;
+    pProgram->nCsr = sSubParse.nTab;
+    pProgram->token = (void *)pTrigger;
+    pPrg->aColmask[0] = sSubParse.oldmask;
+    pPrg->aColmask[1] = sSubParse.newmask;
+    sqlite3VdbeDelete(v);
+  }else{
+    transferParseError(pParse, &sSubParse);
+  }
+
+  assert( !sSubParse.pTriggerPrg && !sSubParse.nMaxArg );
+  sqlite3ParseObjectReset(&sSubParse);
+  return pPrg;
+}
+
+/*
+** Return a pointer to a TriggerPrg object containing the sub-program for
+** trigger pTrigger with default ON CONFLICT algorithm orconf. If no such
+** TriggerPrg object exists, a new object is allocated and populated before
+** being returned.
+*/
+static TriggerPrg *getRowTrigger(
+  Parse *pParse,       /* Current parse context */
+  Trigger *pTrigger,   /* Trigger to code */
+  Table *pTab,         /* The table trigger pTrigger is attached to */
+  int orconf           /* ON CONFLICT algorithm. */
+){
+  Parse *pRoot = sqlite3ParseToplevel(pParse);
+  TriggerPrg *pPrg;
+
+  assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
+
+  /* It may be that this trigger has already been coded (or is in the
+  ** process of being coded). If this is the case, then an entry with
+  ** a matching TriggerPrg.pTrigger field will be present somewhere
+  ** in the Parse.pTriggerPrg list. Search for such an entry.  */
+  for(pPrg=pRoot->pTriggerPrg;
+      pPrg && (pPrg->pTrigger!=pTrigger || pPrg->orconf!=orconf);
+      pPrg=pPrg->pNext
+  );
+
+  /* If an existing TriggerPrg could not be located, create a new one. */
+  if( !pPrg ){
+    pPrg = codeRowTrigger(pParse, pTrigger, pTab, orconf);
+    pParse->db->errByteOffset = -1;
+  }
+
+  return pPrg;
+}
+
+/*
+** Generate code for the trigger program associated with trigger p on
+** table pTab. The reg, orconf and ignoreJump parameters passed to this
+** function are the same as those described in the header function for
+** sqlite3CodeRowTrigger()
+*/
+SQLITE_PRIVATE void sqlite3CodeRowTriggerDirect(
+  Parse *pParse,       /* Parse context */
+  Trigger *p,          /* Trigger to code */
+  Table *pTab,         /* The table to code triggers from */
+  int reg,             /* Reg array containing OLD.* and NEW.* values */
+  int orconf,          /* ON CONFLICT policy */
+  int ignoreJump       /* Instruction to jump to for RAISE(IGNORE) */
+){
+  Vdbe *v = sqlite3GetVdbe(pParse); /* Main VM */
+  TriggerPrg *pPrg;
+  pPrg = getRowTrigger(pParse, p, pTab, orconf);
+  assert( pPrg || pParse->nErr );
+
+  /* Code the OP_Program opcode in the parent VDBE. P4 of the OP_Program
+  ** is a pointer to the sub-vdbe containing the trigger program.  */
+  if( pPrg ){
+    int bRecursive = (p->zName && 0==(pParse->db->flags&SQLITE_RecTriggers));
+
+    sqlite3VdbeAddOp4(v, OP_Program, reg, ignoreJump, ++pParse->nMem,
+                      (const char *)pPrg->pProgram, P4_SUBPROGRAM);
+    VdbeComment(
+        (v, "Call: %s.%s", (p->zName?p->zName:"fkey"), onErrorText(orconf)));
+
+    /* Set the P5 operand of the OP_Program instruction to non-zero if
+    ** recursive invocation of this trigger program is disallowed. Recursive
+    ** invocation is disallowed if (a) the sub-program is really a trigger,
+    ** not a foreign key action, and (b) the flag to enable recursive triggers
+    ** is clear.  */
+    sqlite3VdbeChangeP5(v, (u16)bRecursive);
+  }
+}
+
+/*
+** This is called to code the required FOR EACH ROW triggers for an operation
+** on table pTab. The operation to code triggers for (INSERT, UPDATE or DELETE)
+** is given by the op parameter. The tr_tm parameter determines whether the
+** BEFORE or AFTER triggers are coded. If the operation is an UPDATE, then
+** parameter pChanges is passed the list of columns being modified.
+**
+** If there are no triggers that fire at the specified time for the specified
+** operation on pTab, this function is a no-op.
+**
+** The reg argument is the address of the first in an array of registers
+** that contain the values substituted for the new.* and old.* references
+** in the trigger program. If N is the number of columns in table pTab
+** (a copy of pTab->nCol), then registers are populated as follows:
+**
+**   Register       Contains
+**   ------------------------------------------------------
+**   reg+0          OLD.rowid
+**   reg+1          OLD.* value of left-most column of pTab
+**   ...            ...
+**   reg+N          OLD.* value of right-most column of pTab
+**   reg+N+1        NEW.rowid
+**   reg+N+2        NEW.* value of left-most column of pTab
+**   ...            ...
+**   reg+N+N+1      NEW.* value of right-most column of pTab
+**
+** For ON DELETE triggers, the registers containing the NEW.* values will
+** never be accessed by the trigger program, so they are not allocated or
+** populated by the caller (there is no data to populate them with anyway).
+** Similarly, for ON INSERT triggers the values stored in the OLD.* registers
+** are never accessed, and so are not allocated by the caller. So, for an
+** ON INSERT trigger, the value passed to this function as parameter reg
+** is not a readable register, although registers (reg+N) through
+** (reg+N+N+1) are.
+**
+** Parameter orconf is the default conflict resolution algorithm for the
+** trigger program to use (REPLACE, IGNORE etc.). Parameter ignoreJump
+** is the instruction that control should jump to if a trigger program
+** raises an IGNORE exception.
+*/
+SQLITE_PRIVATE void sqlite3CodeRowTrigger(
+  Parse *pParse,       /* Parse context */
+  Trigger *pTrigger,   /* List of triggers on table pTab */
+  int op,              /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
+  ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
+  int tr_tm,           /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
+  Table *pTab,         /* The table to code triggers from */
+  int reg,             /* The first in an array of registers (see above) */
+  int orconf,          /* ON CONFLICT policy */
+  int ignoreJump       /* Instruction to jump to for RAISE(IGNORE) */
+){
+  Trigger *p;          /* Used to iterate through pTrigger list */
+
+  assert( op==TK_UPDATE || op==TK_INSERT || op==TK_DELETE );
+  assert( tr_tm==TRIGGER_BEFORE || tr_tm==TRIGGER_AFTER );
+  assert( (op==TK_UPDATE)==(pChanges!=0) );
+
+  for(p=pTrigger; p; p=p->pNext){
+
+    /* Sanity checking:  The schema for the trigger and for the table are
+    ** always defined.  The trigger must be in the same schema as the table
+    ** or else it must be a TEMP trigger. */
+    assert( p->pSchema!=0 );
+    assert( p->pTabSchema!=0 );
+    assert( p->pSchema==p->pTabSchema
+         || p->pSchema==pParse->db->aDb[1].pSchema );
+
+    /* Determine whether we should code this trigger.  One of two choices:
+    **   1. The trigger is an exact match to the current DML statement
+    **   2. This is a RETURNING trigger for INSERT but we are currently
+    **      doing the UPDATE part of an UPSERT.
+    */
+    if( (p->op==op || (p->bReturning && p->op==TK_INSERT && op==TK_UPDATE))
+     && p->tr_tm==tr_tm
+     && checkColumnOverlap(p->pColumns, pChanges)
+    ){
+      if( !p->bReturning ){
+        sqlite3CodeRowTriggerDirect(pParse, p, pTab, reg, orconf, ignoreJump);
+      }else if( sqlite3IsToplevel(pParse) ){
+        codeReturningTrigger(pParse, p, pTab, reg);
+      }
+    }
+  }
+}
+
+/*
+** Triggers may access values stored in the old.* or new.* pseudo-table.
+** This function returns a 32-bit bitmask indicating which columns of the
+** old.* or new.* tables actually are used by triggers. This information
+** may be used by the caller, for example, to avoid having to load the entire
+** old.* record into memory when executing an UPDATE or DELETE command.
+**
+** Bit 0 of the returned mask is set if the left-most column of the
+** table may be accessed using an [old|new].<col> reference. Bit 1 is set if
+** the second leftmost column value is required, and so on. If there
+** are more than 32 columns in the table, and at least one of the columns
+** with an index greater than 32 may be accessed, 0xffffffff is returned.
+**
+** It is not possible to determine if the old.rowid or new.rowid column is
+** accessed by triggers. The caller must always assume that it is.
+**
+** Parameter isNew must be either 1 or 0. If it is 0, then the mask returned
+** applies to the old.* table. If 1, the new.* table.
+**
+** Parameter tr_tm must be a mask with one or both of the TRIGGER_BEFORE
+** and TRIGGER_AFTER bits set. Values accessed by BEFORE triggers are only
+** included in the returned mask if the TRIGGER_BEFORE bit is set in the
+** tr_tm parameter. Similarly, values accessed by AFTER triggers are only
+** included in the returned mask if the TRIGGER_AFTER bit is set in tr_tm.
+*/
+SQLITE_PRIVATE u32 sqlite3TriggerColmask(
+  Parse *pParse,       /* Parse context */
+  Trigger *pTrigger,   /* List of triggers on table pTab */
+  ExprList *pChanges,  /* Changes list for any UPDATE OF triggers */
+  int isNew,           /* 1 for new.* ref mask, 0 for old.* ref mask */
+  int tr_tm,           /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
+  Table *pTab,         /* The table to code triggers from */
+  int orconf           /* Default ON CONFLICT policy for trigger steps */
+){
+  const int op = pChanges ? TK_UPDATE : TK_DELETE;
+  u32 mask = 0;
+  Trigger *p;
+
+  assert( isNew==1 || isNew==0 );
+  if( IsView(pTab) ){
+    return 0xffffffff;
+  }
+  for(p=pTrigger; p; p=p->pNext){
+    if( p->op==op
+     && (tr_tm&p->tr_tm)
+     && checkColumnOverlap(p->pColumns,pChanges)
+    ){
+      if( p->bReturning ){
+        mask = 0xffffffff;
+      }else{
+        TriggerPrg *pPrg;
+        pPrg = getRowTrigger(pParse, p, pTab, orconf);
+        if( pPrg ){
+          mask |= pPrg->aColmask[isNew];
+        }
+      }
+    }
+  }
+
+  return mask;
+}
+
+#endif /* !defined(SQLITE_OMIT_TRIGGER) */
+
+/************** End of trigger.c *********************************************/
+/************** Begin file update.c ******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle UPDATE statements.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* Forward declaration */
+static void updateVirtualTable(
+  Parse *pParse,       /* The parsing context */
+  SrcList *pSrc,       /* The virtual table to be modified */
+  Table *pTab,         /* The virtual table */
+  ExprList *pChanges,  /* The columns to change in the UPDATE statement */
+  Expr *pRowidExpr,    /* Expression used to recompute the rowid */
+  int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
+  Expr *pWhere,        /* WHERE clause of the UPDATE statement */
+  int onError          /* ON CONFLICT strategy */
+);
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** The most recently coded instruction was an OP_Column to retrieve the
+** i-th column of table pTab. This routine sets the P4 parameter of the
+** OP_Column to the default value, if any.
+**
+** The default value of a column is specified by a DEFAULT clause in the
+** column definition. This was either supplied by the user when the table
+** was created, or added later to the table definition by an ALTER TABLE
+** command. If the latter, then the row-records in the table btree on disk
+** may not contain a value for the column and the default value, taken
+** from the P4 parameter of the OP_Column instruction, is returned instead.
+** If the former, then all row-records are guaranteed to include a value
+** for the column and the P4 value is not required.
+**
+** Column definitions created by an ALTER TABLE command may only have
+** literal default values specified: a number, null or a string. (If a more
+** complicated default expression value was provided, it is evaluated
+** when the ALTER TABLE is executed and one of the literal values written
+** into the sqlite_schema table.)
+**
+** Therefore, the P4 parameter is only required if the default value for
+** the column is a literal number, string or null. The sqlite3ValueFromExpr()
+** function is capable of transforming these types of expressions into
+** sqlite3_value objects.
+**
+** If column as REAL affinity and the table is an ordinary b-tree table
+** (not a virtual table) then the value might have been stored as an
+** integer.  In that case, add an OP_RealAffinity opcode to make sure
+** it has been converted into REAL.
+*/
+SQLITE_PRIVATE void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i, int iReg){
+  Column *pCol;
+  assert( pTab!=0 );
+  assert( pTab->nCol>i );
+  pCol = &pTab->aCol[i];
+  if( pCol->iDflt ){
+    sqlite3_value *pValue = 0;
+    u8 enc = ENC(sqlite3VdbeDb(v));
+    assert( !IsView(pTab) );
+    VdbeComment((v, "%s.%s", pTab->zName, pCol->zCnName));
+    assert( i<pTab->nCol );
+    sqlite3ValueFromExpr(sqlite3VdbeDb(v),
+                         sqlite3ColumnExpr(pTab,pCol), enc,
+                         pCol->affinity, &pValue);
+    if( pValue ){
+      sqlite3VdbeAppendP4(v, pValue, P4_MEM);
+    }
+  }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  if( pCol->affinity==SQLITE_AFF_REAL && !IsVirtual(pTab) ){
+    sqlite3VdbeAddOp1(v, OP_RealAffinity, iReg);
+  }
+#endif
+}
+
+/*
+** Check to see if column iCol of index pIdx references any of the
+** columns defined by aXRef and chngRowid.  Return true if it does
+** and false if not.  This is an optimization.  False-positives are a
+** performance degradation, but false-negatives can result in a corrupt
+** index and incorrect answers.
+**
+** aXRef[j] will be non-negative if column j of the original table is
+** being updated.  chngRowid will be true if the rowid of the table is
+** being updated.
+*/
+static int indexColumnIsBeingUpdated(
+  Index *pIdx,      /* The index to check */
+  int iCol,         /* Which column of the index to check */
+  int *aXRef,       /* aXRef[j]>=0 if column j is being updated */
+  int chngRowid     /* true if the rowid is being updated */
+){
+  i16 iIdxCol = pIdx->aiColumn[iCol];
+  assert( iIdxCol!=XN_ROWID ); /* Cannot index rowid */
+  if( iIdxCol>=0 ){
+    return aXRef[iIdxCol]>=0;
+  }
+  assert( iIdxCol==XN_EXPR );
+  assert( pIdx->aColExpr!=0 );
+  assert( pIdx->aColExpr->a[iCol].pExpr!=0 );
+  return sqlite3ExprReferencesUpdatedColumn(pIdx->aColExpr->a[iCol].pExpr,
+                                            aXRef,chngRowid);
+}
+
+/*
+** Check to see if index pIdx is a partial index whose conditional
+** expression might change values due to an UPDATE.  Return true if
+** the index is subject to change and false if the index is guaranteed
+** to be unchanged.  This is an optimization.  False-positives are a
+** performance degradation, but false-negatives can result in a corrupt
+** index and incorrect answers.
+**
+** aXRef[j] will be non-negative if column j of the original table is
+** being updated.  chngRowid will be true if the rowid of the table is
+** being updated.
+*/
+static int indexWhereClauseMightChange(
+  Index *pIdx,      /* The index to check */
+  int *aXRef,       /* aXRef[j]>=0 if column j is being updated */
+  int chngRowid     /* true if the rowid is being updated */
+){
+  if( pIdx->pPartIdxWhere==0 ) return 0;
+  return sqlite3ExprReferencesUpdatedColumn(pIdx->pPartIdxWhere,
+                                            aXRef, chngRowid);
+}
+
+/*
+** Allocate and return a pointer to an expression of type TK_ROW with
+** Expr.iColumn set to value (iCol+1). The resolver will modify the
+** expression to be a TK_COLUMN reading column iCol of the first
+** table in the source-list (pSrc->a[0]).
+*/
+static Expr *exprRowColumn(Parse *pParse, int iCol){
+  Expr *pRet = sqlite3PExpr(pParse, TK_ROW, 0, 0);
+  if( pRet ) pRet->iColumn = iCol+1;
+  return pRet;
+}
+
+/*
+** Assuming both the pLimit and pOrderBy parameters are NULL, this function
+** generates VM code to run the query:
+**
+**   SELECT <other-columns>, pChanges FROM pTabList WHERE pWhere
+**
+** and write the results to the ephemeral table already opened as cursor
+** iEph. None of pChanges, pTabList or pWhere are modified or consumed by
+** this function, they must be deleted by the caller.
+**
+** Or, if pLimit and pOrderBy are not NULL, and pTab is not a view:
+**
+**   SELECT <other-columns>, pChanges FROM pTabList
+**   WHERE pWhere
+**   GROUP BY <other-columns>
+**   ORDER BY pOrderBy LIMIT pLimit
+**
+** If pTab is a view, the GROUP BY clause is omitted.
+**
+** Exactly how results are written to table iEph, and exactly what
+** the <other-columns> in the query above are is determined by the type
+** of table pTabList->a[0].pTab.
+**
+** If the table is a WITHOUT ROWID table, then argument pPk must be its
+** PRIMARY KEY. In this case <other-columns> are the primary key columns
+** of the table, in order. The results of the query are written to ephemeral
+** table iEph as index keys, using OP_IdxInsert.
+**
+** If the table is actually a view, then <other-columns> are all columns of
+** the view. The results are written to the ephemeral table iEph as records
+** with automatically assigned integer keys.
+**
+** If the table is a virtual or ordinary intkey table, then <other-columns>
+** is its rowid. For a virtual table, the results are written to iEph as
+** records with automatically assigned integer keys For intkey tables, the
+** rowid value in <other-columns> is used as the integer key, and the
+** remaining fields make up the table record.
+*/
+static void updateFromSelect(
+  Parse *pParse,                  /* Parse context */
+  int iEph,                       /* Cursor for open eph. table */
+  Index *pPk,                     /* PK if table 0 is WITHOUT ROWID */
+  ExprList *pChanges,             /* List of expressions to return */
+  SrcList *pTabList,              /* List of tables to select from */
+  Expr *pWhere,                   /* WHERE clause for query */
+  ExprList *pOrderBy,             /* ORDER BY clause */
+  Expr *pLimit                    /* LIMIT clause */
+){
+  int i;
+  SelectDest dest;
+  Select *pSelect = 0;
+  ExprList *pList = 0;
+  ExprList *pGrp = 0;
+  Expr *pLimit2 = 0;
+  ExprList *pOrderBy2 = 0;
+  sqlite3 *db = pParse->db;
+  Table *pTab = pTabList->a[0].pSTab;
+  SrcList *pSrc;
+  Expr *pWhere2;
+  int eDest;
+
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( pOrderBy && pLimit==0 ) {
+    sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on UPDATE");
+    return;
+  }
+  pOrderBy2 = sqlite3ExprListDup(db, pOrderBy, 0);
+  pLimit2 = sqlite3ExprDup(db, pLimit, 0);
+#else
+  UNUSED_PARAMETER(pOrderBy);
+  UNUSED_PARAMETER(pLimit);
+#endif
+
+  pSrc = sqlite3SrcListDup(db, pTabList, 0);
+  pWhere2 = sqlite3ExprDup(db, pWhere, 0);
+
+  assert( pTabList->nSrc>1 );
+  if( pSrc ){
+    assert( pSrc->a[0].fg.notCte );
+    pSrc->a[0].iCursor = -1;
+    pSrc->a[0].pSTab->nTabRef--;
+    pSrc->a[0].pSTab = 0;
+  }
+  if( pPk ){
+    for(i=0; i<pPk->nKeyCol; i++){
+      Expr *pNew = exprRowColumn(pParse, pPk->aiColumn[i]);
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+      if( pLimit ){
+        pGrp = sqlite3ExprListAppend(pParse, pGrp, sqlite3ExprDup(db, pNew, 0));
+      }
+#endif
+      pList = sqlite3ExprListAppend(pParse, pList, pNew);
+    }
+    eDest = IsVirtual(pTab) ? SRT_Table : SRT_Upfrom;
+  }else if( IsView(pTab) ){
+    for(i=0; i<pTab->nCol; i++){
+      pList = sqlite3ExprListAppend(pParse, pList, exprRowColumn(pParse, i));
+    }
+    eDest = SRT_Table;
+  }else{
+    eDest = IsVirtual(pTab) ? SRT_Table : SRT_Upfrom;
+    pList = sqlite3ExprListAppend(pParse, 0, sqlite3PExpr(pParse,TK_ROW,0,0));
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+    if( pLimit ){
+      pGrp = sqlite3ExprListAppend(pParse, 0, sqlite3PExpr(pParse,TK_ROW,0,0));
+    }
+#endif
+  }
+  assert( pChanges!=0 || pParse->db->mallocFailed );
+  if( pChanges ){
+    for(i=0; i<pChanges->nExpr; i++){
+      pList = sqlite3ExprListAppend(pParse, pList,
+          sqlite3ExprDup(db, pChanges->a[i].pExpr, 0)
+      );
+    }
+  }
+  pSelect = sqlite3SelectNew(pParse, pList,
+      pSrc, pWhere2, pGrp, 0, pOrderBy2,
+      SF_UFSrcCheck|SF_IncludeHidden|SF_UpdateFrom, pLimit2
+  );
+  if( pSelect ) pSelect->selFlags |= SF_OrderByReqd;
+  sqlite3SelectDestInit(&dest, eDest, iEph);
+  dest.iSDParm2 = (pPk ? pPk->nKeyCol : -1);
+  sqlite3Select(pParse, pSelect, &dest);
+  sqlite3SelectDelete(db, pSelect);
+}
+
+/*
+** Process an UPDATE statement.
+**
+**   UPDATE OR IGNORE tbl SET a=b, c=d FROM tbl2... WHERE e<5 AND f NOT NULL;
+**          \_______/ \_/     \______/      \_____/       \________________/
+**           onError   |      pChanges         |                pWhere
+**                     \_______________________/
+**                               pTabList
+*/
+SQLITE_PRIVATE void sqlite3Update(
+  Parse *pParse,         /* The parser context */
+  SrcList *pTabList,     /* The table in which we should change things */
+  ExprList *pChanges,    /* Things to be changed */
+  Expr *pWhere,          /* The WHERE clause.  May be null */
+  int onError,           /* How to handle constraint errors */
+  ExprList *pOrderBy,    /* ORDER BY clause. May be null */
+  Expr *pLimit,          /* LIMIT clause. May be null */
+  Upsert *pUpsert        /* ON CONFLICT clause, or null */
+){
+  int i, j, k;           /* Loop counters */
+  Table *pTab;           /* The table to be updated */
+  int addrTop = 0;       /* VDBE instruction address of the start of the loop */
+  WhereInfo *pWInfo = 0; /* Information about the WHERE clause */
+  Vdbe *v;               /* The virtual database engine */
+  Index *pIdx;           /* For looping over indices */
+  Index *pPk;            /* The PRIMARY KEY index for WITHOUT ROWID tables */
+  int nIdx;              /* Number of indices that need updating */
+  int nAllIdx;           /* Total number of indexes */
+  int iBaseCur;          /* Base cursor number */
+  int iDataCur;          /* Cursor for the canonical data btree */
+  int iIdxCur;           /* Cursor for the first index */
+  sqlite3 *db;           /* The database structure */
+  int *aRegIdx = 0;      /* Registers for to each index and the main table */
+  int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
+                         ** an expression for the i-th column of the table.
+                         ** aXRef[i]==-1 if the i-th column is not changed. */
+  u8 *aToOpen;           /* 1 for tables and indices to be opened */
+  u8 chngPk;             /* PRIMARY KEY changed in a WITHOUT ROWID table */
+  u8 chngRowid;          /* Rowid changed in a normal table */
+  u8 chngKey;            /* Either chngPk or chngRowid */
+  Expr *pRowidExpr = 0;  /* Expression defining the new record number */
+  int iRowidExpr = -1;   /* Index of "rowid=" (or IPK) assignment in pChanges */
+  AuthContext sContext;  /* The authorization context */
+  NameContext sNC;       /* The name-context to resolve expressions in */
+  int iDb;               /* Database containing the table being updated */
+  int eOnePass;          /* ONEPASS_XXX value from where.c */
+  int hasFK;             /* True if foreign key processing is required */
+  int labelBreak;        /* Jump here to break out of UPDATE loop */
+  int labelContinue;     /* Jump here to continue next step of UPDATE loop */
+  int flags;             /* Flags for sqlite3WhereBegin() */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;            /* True when updating a view (INSTEAD OF trigger) */
+  Trigger *pTrigger;     /* List of triggers on pTab, if required */
+  int tmask;             /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
+#endif
+  int newmask;           /* Mask of NEW.* columns accessed by BEFORE triggers */
+  int iEph = 0;          /* Ephemeral table holding all primary key values */
+  int nKey = 0;          /* Number of elements in regKey for WITHOUT ROWID */
+  int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */
+  int addrOpen = 0;      /* Address of OP_OpenEphemeral */
+  int iPk = 0;           /* First of nPk cells holding PRIMARY KEY value */
+  i16 nPk = 0;           /* Number of components of the PRIMARY KEY */
+  int bReplace = 0;      /* True if REPLACE conflict resolution might happen */
+  int bFinishSeek = 1;   /* The OP_FinishSeek opcode is needed */
+  int nChangeFrom = 0;   /* If there is a FROM, pChanges->nExpr, else 0 */
+
+  /* Register Allocations */
+  int regRowCount = 0;   /* A count of rows changed */
+  int regOldRowid = 0;   /* The old rowid */
+  int regNewRowid = 0;   /* The new rowid */
+  int regNew = 0;        /* Content of the NEW.* table in triggers */
+  int regOld = 0;        /* Content of OLD.* table in triggers */
+  int regRowSet = 0;     /* Rowset of rows to be updated */
+  int regKey = 0;        /* composite PRIMARY KEY value */
+
+  memset(&sContext, 0, sizeof(sContext));
+  db = pParse->db;
+  assert( db->pParse==pParse );
+  if( pParse->nErr ){
+    goto update_cleanup;
+  }
+  assert( db->mallocFailed==0 );
+
+  /* Locate the table which we want to update.
+  */
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 ) goto update_cleanup;
+  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
+
+  /* Figure out if we have any triggers and if the table being
+  ** updated is a view.
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges, &tmask);
+  isView = IsView(pTab);
+  assert( pTrigger || tmask==0 );
+#else
+# define pTrigger 0
+# define isView 0
+# define tmask 0
+#endif
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+
+#if TREETRACE_ENABLED
+  if( sqlite3TreeTrace & 0x10000 ){
+    sqlite3TreeViewLine(0, "In sqlite3Update() at %s:%d", __FILE__, __LINE__);
+    sqlite3TreeViewUpdate(pParse->pWith, pTabList, pChanges, pWhere,
+                          onError, pOrderBy, pLimit, pUpsert, pTrigger);
+  }
+#endif
+
+  /* If there was a FROM clause, set nChangeFrom to the number of expressions
+  ** in the change-list. Otherwise, set it to 0. There cannot be a FROM
+  ** clause if this function is being called to generate code for part of
+  ** an UPSERT statement.  */
+  nChangeFrom = (pTabList->nSrc>1) ? pChanges->nExpr : 0;
+  assert( nChangeFrom==0 || pUpsert==0 );
+
+#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( !isView && nChangeFrom==0 ){
+    pWhere = sqlite3LimitWhere(
+        pParse, pTabList, pWhere, pOrderBy, pLimit, "UPDATE"
+    );
+    pOrderBy = 0;
+    pLimit = 0;
+  }
+#endif
+
+  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+    goto update_cleanup;
+  }
+  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
+    goto update_cleanup;
+  }
+
+  /* Allocate a cursors for the main database table and for all indices.
+  ** The index cursors might not be used, but if they are used they
+  ** need to occur right after the database cursor.  So go ahead and
+  ** allocate enough space, just in case.
+  */
+  iBaseCur = iDataCur = pParse->nTab++;
+  iIdxCur = iDataCur+1;
+  pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
+  testcase( pPk!=0 && pPk!=pTab->pIndex );
+  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
+    if( pPk==pIdx ){
+      iDataCur = pParse->nTab;
+    }
+    pParse->nTab++;
+  }
+  if( pUpsert ){
+    /* On an UPSERT, reuse the same cursors already opened by INSERT */
+    iDataCur = pUpsert->iDataCur;
+    iIdxCur = pUpsert->iIdxCur;
+    pParse->nTab = iBaseCur;
+  }
+  pTabList->a[0].iCursor = iDataCur;
+
+  /* Allocate space for aXRef[], aRegIdx[], and aToOpen[].
+  ** Initialize aXRef[] and aToOpen[] to their default values.
+  */
+  aXRef = sqlite3DbMallocRawNN(db, sizeof(int) * (pTab->nCol+nIdx+1) + nIdx+2 );
+  if( aXRef==0 ) goto update_cleanup;
+  aRegIdx = aXRef+pTab->nCol;
+  aToOpen = (u8*)(aRegIdx+nIdx+1);
+  memset(aToOpen, 1, nIdx+1);
+  aToOpen[nIdx+1] = 0;
+  for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
+
+  /* Initialize the name-context */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  sNC.pSrcList = pTabList;
+  sNC.uNC.pUpsert = pUpsert;
+  sNC.ncFlags = NC_UUpsert;
+
+  /* Begin generating code. */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) goto update_cleanup;
+
+  /* Resolve the column names in all the expressions of the
+  ** of the UPDATE statement.  Also find the column index
+  ** for each column to be updated in the pChanges array.  For each
+  ** column to be updated, make sure we have authorization to change
+  ** that column.
+  */
+  chngRowid = chngPk = 0;
+  for(i=0; i<pChanges->nExpr; i++){
+    u8 hCol = sqlite3StrIHash(pChanges->a[i].zEName);
+    /* If this is an UPDATE with a FROM clause, do not resolve expressions
+    ** here. The call to sqlite3Select() below will do that. */
+    if( nChangeFrom==0 && sqlite3ResolveExprNames(&sNC, pChanges->a[i].pExpr) ){
+      goto update_cleanup;
+    }
+    for(j=0; j<pTab->nCol; j++){
+      if( pTab->aCol[j].hName==hCol
+       && sqlite3StrICmp(pTab->aCol[j].zCnName, pChanges->a[i].zEName)==0
+      ){
+        if( j==pTab->iPKey ){
+          chngRowid = 1;
+          pRowidExpr = pChanges->a[i].pExpr;
+          iRowidExpr = i;
+        }else if( pPk && (pTab->aCol[j].colFlags & COLFLAG_PRIMKEY)!=0 ){
+          chngPk = 1;
+        }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+        else if( pTab->aCol[j].colFlags & COLFLAG_GENERATED ){
+          testcase( pTab->aCol[j].colFlags & COLFLAG_VIRTUAL );
+          testcase( pTab->aCol[j].colFlags & COLFLAG_STORED );
+          sqlite3ErrorMsg(pParse,
+             "cannot UPDATE generated column \"%s\"",
+             pTab->aCol[j].zCnName);
+          goto update_cleanup;
+        }
+#endif
+        aXRef[j] = i;
+        break;
+      }
+    }
+    if( j>=pTab->nCol ){
+      if( pPk==0 && sqlite3IsRowid(pChanges->a[i].zEName) ){
+        j = -1;
+        chngRowid = 1;
+        pRowidExpr = pChanges->a[i].pExpr;
+        iRowidExpr = i;
+      }else{
+        sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zEName);
+        pParse->checkSchema = 1;
+        goto update_cleanup;
+      }
+    }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    {
+      int rc;
+      rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
+                            j<0 ? "ROWID" : pTab->aCol[j].zCnName,
+                            db->aDb[iDb].zDbSName);
+      if( rc==SQLITE_DENY ){
+        goto update_cleanup;
+      }else if( rc==SQLITE_IGNORE ){
+        aXRef[j] = -1;
+      }
+    }
+#endif
+  }
+  assert( (chngRowid & chngPk)==0 );
+  assert( chngRowid==0 || chngRowid==1 );
+  assert( chngPk==0 || chngPk==1 );
+  chngKey = chngRowid + chngPk;
+
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  /* Mark generated columns as changing if their generator expressions
+  ** reference any changing column.  The actual aXRef[] value for
+  ** generated expressions is not used, other than to check to see that it
+  ** is non-negative, so the value of aXRef[] for generated columns can be
+  ** set to any non-negative number.  We use 99999 so that the value is
+  ** obvious when looking at aXRef[] in a symbolic debugger.
+  */
+  if( pTab->tabFlags & TF_HasGenerated ){
+    int bProgress;
+    testcase( pTab->tabFlags & TF_HasVirtual );
+    testcase( pTab->tabFlags & TF_HasStored );
+    do{
+      bProgress = 0;
+      for(i=0; i<pTab->nCol; i++){
+        if( aXRef[i]>=0 ) continue;
+        if( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)==0 ) continue;
+        if( sqlite3ExprReferencesUpdatedColumn(
+                sqlite3ColumnExpr(pTab, &pTab->aCol[i]),
+                 aXRef, chngRowid)
+        ){
+          aXRef[i] = 99999;
+          bProgress = 1;
+        }
+      }
+    }while( bProgress );
+  }
+#endif
+
+  /* The SET expressions are not actually used inside the WHERE loop.
+  ** So reset the colUsed mask. Unless this is a virtual table. In that
+  ** case, set all bits of the colUsed mask (to ensure that the virtual
+  ** table implementation makes all columns available).
+  */
+  pTabList->a[0].colUsed = IsVirtual(pTab) ? ALLBITS : 0;
+
+  hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngKey);
+
+  /* There is one entry in the aRegIdx[] array for each index on the table
+  ** being updated.  Fill in aRegIdx[] with a register number that will hold
+  ** the key for accessing each index.
+  */
+  if( onError==OE_Replace ) bReplace = 1;
+  for(nAllIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nAllIdx++){
+    int reg;
+    if( chngKey || hasFK>1 || pIdx==pPk
+     || indexWhereClauseMightChange(pIdx,aXRef,chngRowid)
+    ){
+      reg = ++pParse->nMem;
+      pParse->nMem += pIdx->nColumn;
+    }else{
+      reg = 0;
+      for(i=0; i<pIdx->nKeyCol; i++){
+        if( indexColumnIsBeingUpdated(pIdx, i, aXRef, chngRowid) ){
+          reg = ++pParse->nMem;
+          pParse->nMem += pIdx->nColumn;
+          if( onError==OE_Default && pIdx->onError==OE_Replace ){
+            bReplace = 1;
+          }
+          break;
+        }
+      }
+    }
+    if( reg==0 ) aToOpen[nAllIdx+1] = 0;
+    aRegIdx[nAllIdx] = reg;
+  }
+  aRegIdx[nAllIdx] = ++pParse->nMem;  /* Register storing the table record */
+  if( bReplace ){
+    /* If REPLACE conflict resolution might be invoked, open cursors on all
+    ** indexes in case they are needed to delete records.  */
+    memset(aToOpen, 1, nIdx+1);
+  }
+
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, pTrigger || hasFK, iDb);
+
+  /* Allocate required registers. */
+  if( !IsVirtual(pTab) ){
+    /* For now, regRowSet and aRegIdx[nAllIdx] share the same register.
+    ** If regRowSet turns out to be needed, then aRegIdx[nAllIdx] will be
+    ** reallocated.  aRegIdx[nAllIdx] is the register in which the main
+    ** table record is written.  regRowSet holds the RowSet for the
+    ** two-pass update algorithm. */
+    assert( aRegIdx[nAllIdx]==pParse->nMem );
+    regRowSet = aRegIdx[nAllIdx];
+    regOldRowid = regNewRowid = ++pParse->nMem;
+    if( chngPk || pTrigger || hasFK ){
+      regOld = pParse->nMem + 1;
+      pParse->nMem += pTab->nCol;
+    }
+    if( chngKey || pTrigger || hasFK ){
+      regNewRowid = ++pParse->nMem;
+    }
+    regNew = pParse->nMem + 1;
+    pParse->nMem += pTab->nCol;
+  }
+
+  /* Start the view context. */
+  if( isView ){
+    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
+  }
+
+  /* If we are trying to update a view, realize that view into
+  ** an ephemeral table.
+  */
+#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
+  if( nChangeFrom==0 && isView ){
+    sqlite3MaterializeView(pParse, pTab,
+        pWhere, pOrderBy, pLimit, iDataCur
+    );
+    pOrderBy = 0;
+    pLimit = 0;
+  }
+#endif
+
+  /* Resolve the column names in all the expressions in the
+  ** WHERE clause.
+  */
+  if( nChangeFrom==0 && sqlite3ResolveExprNames(&sNC, pWhere) ){
+    goto update_cleanup;
+  }
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  /* Virtual tables must be handled separately */
+  if( IsVirtual(pTab) ){
+    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
+                       pWhere, onError);
+    goto update_cleanup;
+  }
+#endif
+
+  /* Jump to labelBreak to abandon further processing of this UPDATE */
+  labelContinue = labelBreak = sqlite3VdbeMakeLabel(pParse);
+
+  /* Not an UPSERT.  Normal processing.  Begin by
+  ** initialize the count of updated rows */
+  if( (db->flags&SQLITE_CountRows)!=0
+   && !pParse->pTriggerTab
+   && !pParse->nested
+   && !pParse->bReturning
+   && pUpsert==0
+  ){
+    regRowCount = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
+  }
+
+  if( nChangeFrom==0 && HasRowid(pTab) ){
+    sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
+    iEph = pParse->nTab++;
+    addrOpen = sqlite3VdbeAddOp3(v, OP_OpenEphemeral, iEph, 0, regRowSet);
+  }else{
+    assert( pPk!=0 || HasRowid(pTab) );
+    nPk = pPk ? pPk->nKeyCol : 0;
+    iPk = pParse->nMem+1;
+    pParse->nMem += nPk;
+    pParse->nMem += nChangeFrom;
+    regKey = ++pParse->nMem;
+    if( pUpsert==0 ){
+      int nEphCol = nPk + nChangeFrom + (isView ? pTab->nCol : 0);
+      iEph = pParse->nTab++;
+      if( pPk ) sqlite3VdbeAddOp3(v, OP_Null, 0, iPk, iPk+nPk-1);
+      addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nEphCol);
+      if( pPk ){
+        KeyInfo *pKeyInfo = sqlite3KeyInfoOfIndex(pParse, pPk);
+        if( pKeyInfo ){
+          pKeyInfo->nAllField = nEphCol;
+          sqlite3VdbeAppendP4(v, pKeyInfo, P4_KEYINFO);
+        }
+      }
+      if( nChangeFrom ){
+        updateFromSelect(
+            pParse, iEph, pPk, pChanges, pTabList, pWhere, pOrderBy, pLimit
+        );
+#ifndef SQLITE_OMIT_SUBQUERY
+        if( isView ) iDataCur = iEph;
+#endif
+      }
+    }
+  }
+
+  if( nChangeFrom ){
+    sqlite3MultiWrite(pParse);
+    eOnePass = ONEPASS_OFF;
+    nKey = nPk;
+    regKey = iPk;
+  }else{
+    if( pUpsert ){
+      /* If this is an UPSERT, then all cursors have already been opened by
+      ** the outer INSERT and the data cursor should be pointing at the row
+      ** that is to be updated.  So bypass the code that searches for the
+      ** row(s) to be updated.
+      */
+      pWInfo = 0;
+      eOnePass = ONEPASS_SINGLE;
+      sqlite3ExprIfFalse(pParse, pWhere, labelBreak, SQLITE_JUMPIFNULL);
+      bFinishSeek = 0;
+    }else{
+      /* Begin the database scan.
+      **
+      ** Do not consider a single-pass strategy for a multi-row update if
+      ** there is anything that might disrupt the cursor being used to do
+      ** the UPDATE:
+      **   (1) This is a nested UPDATE
+      **   (2) There are triggers
+      **   (3) There are FOREIGN KEY constraints
+      **   (4) There are REPLACE conflict handlers
+      **   (5) There are subqueries in the WHERE clause
+      */
+      flags = WHERE_ONEPASS_DESIRED;
+      if( !pParse->nested
+       && !pTrigger
+       && !hasFK
+       && !chngKey
+       && !bReplace
+       && (pWhere==0 || !ExprHasProperty(pWhere, EP_Subquery))
+      ){
+        flags |= WHERE_ONEPASS_MULTIROW;
+      }
+      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere,0,0,0,flags,iIdxCur);
+      if( pWInfo==0 ) goto update_cleanup;
+
+      /* A one-pass strategy that might update more than one row may not
+      ** be used if any column of the index used for the scan is being
+      ** updated. Otherwise, if there is an index on "b", statements like
+      ** the following could create an infinite loop:
+      **
+      **   UPDATE t1 SET b=b+1 WHERE b>?
+      **
+      ** Fall back to ONEPASS_OFF if where.c has selected a ONEPASS_MULTI
+      ** strategy that uses an index for which one or more columns are being
+      ** updated.  */
+      eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
+      bFinishSeek = sqlite3WhereUsesDeferredSeek(pWInfo);
+      if( eOnePass!=ONEPASS_SINGLE ){
+        sqlite3MultiWrite(pParse);
+        if( eOnePass==ONEPASS_MULTI ){
+          int iCur = aiCurOnePass[1];
+          if( iCur>=0 && iCur!=iDataCur && aToOpen[iCur-iBaseCur] ){
+            eOnePass = ONEPASS_OFF;
+          }
+          assert( iCur!=iDataCur || !HasRowid(pTab) );
+        }
+      }
+    }
+
+    if( HasRowid(pTab) ){
+      /* Read the rowid of the current row of the WHERE scan. In ONEPASS_OFF
+      ** mode, write the rowid into the FIFO. In either of the one-pass modes,
+      ** leave it in register regOldRowid.  */
+      sqlite3VdbeAddOp2(v, OP_Rowid, iDataCur, regOldRowid);
+      if( eOnePass==ONEPASS_OFF ){
+        aRegIdx[nAllIdx] = ++pParse->nMem;
+        sqlite3VdbeAddOp3(v, OP_Insert, iEph, regRowSet, regOldRowid);
+      }else{
+        if( ALWAYS(addrOpen) ) sqlite3VdbeChangeToNoop(v, addrOpen);
+      }
+    }else{
+      /* Read the PK of the current row into an array of registers. In
+      ** ONEPASS_OFF mode, serialize the array into a record and store it in
+      ** the ephemeral table. Or, in ONEPASS_SINGLE or MULTI mode, change
+      ** the OP_OpenEphemeral instruction to a Noop (the ephemeral table
+      ** is not required) and leave the PK fields in the array of registers.  */
+      for(i=0; i<nPk; i++){
+        assert( pPk->aiColumn[i]>=0 );
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur,
+                                        pPk->aiColumn[i], iPk+i);
+      }
+      if( eOnePass ){
+        if( addrOpen ) sqlite3VdbeChangeToNoop(v, addrOpen);
+        nKey = nPk;
+        regKey = iPk;
+      }else{
+        sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, regKey,
+                          sqlite3IndexAffinityStr(db, pPk), nPk);
+        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEph, regKey, iPk, nPk);
+      }
+    }
+  }
+
+  if( pUpsert==0 ){
+    if( nChangeFrom==0 && eOnePass!=ONEPASS_MULTI ){
+      sqlite3WhereEnd(pWInfo);
+    }
+
+    if( !isView ){
+      int addrOnce = 0;
+      int iNotUsed1 = 0;
+      int iNotUsed2 = 0;
+
+      /* Open every index that needs updating. */
+      if( eOnePass!=ONEPASS_OFF ){
+        if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iBaseCur] = 0;
+        if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iBaseCur] = 0;
+      }
+
+      if( eOnePass==ONEPASS_MULTI && (nIdx-(aiCurOnePass[1]>=0))>0 ){
+        addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+      }
+      sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, iBaseCur,
+                                 aToOpen, &iNotUsed1, &iNotUsed2);
+      if( addrOnce ){
+        sqlite3VdbeJumpHereOrPopInst(v, addrOnce);
+      }
+    }
+
+    /* Top of the update loop */
+    if( eOnePass!=ONEPASS_OFF ){
+      if( aiCurOnePass[0]!=iDataCur
+       && aiCurOnePass[1]!=iDataCur
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+       && !isView
+#endif
+      ){
+        assert( pPk );
+        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey,nKey);
+        VdbeCoverage(v);
+      }
+      if( eOnePass!=ONEPASS_SINGLE ){
+        labelContinue = sqlite3VdbeMakeLabel(pParse);
+      }
+      sqlite3VdbeAddOp2(v, OP_IsNull, pPk ? regKey : regOldRowid, labelBreak);
+      VdbeCoverageIf(v, pPk==0);
+      VdbeCoverageIf(v, pPk!=0);
+    }else if( pPk || nChangeFrom ){
+      labelContinue = sqlite3VdbeMakeLabel(pParse);
+      sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak); VdbeCoverage(v);
+      addrTop = sqlite3VdbeCurrentAddr(v);
+      if( nChangeFrom ){
+        if( !isView ){
+          if( pPk ){
+            for(i=0; i<nPk; i++){
+              sqlite3VdbeAddOp3(v, OP_Column, iEph, i, iPk+i);
+            }
+            sqlite3VdbeAddOp4Int(
+                v, OP_NotFound, iDataCur, labelContinue, iPk, nPk
+            ); VdbeCoverage(v);
+          }else{
+            sqlite3VdbeAddOp2(v, OP_Rowid, iEph, regOldRowid);
+            sqlite3VdbeAddOp3(
+                v, OP_NotExists, iDataCur, labelContinue, regOldRowid
+            ); VdbeCoverage(v);
+          }
+        }
+      }else{
+        sqlite3VdbeAddOp2(v, OP_RowData, iEph, regKey);
+        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelContinue, regKey,0);
+        VdbeCoverage(v);
+      }
+    }else{
+      sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak); VdbeCoverage(v);
+      labelContinue = sqlite3VdbeMakeLabel(pParse);
+      addrTop = sqlite3VdbeAddOp2(v, OP_Rowid, iEph, regOldRowid);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue, regOldRowid);
+      VdbeCoverage(v);
+    }
+  }
+
+  /* If the rowid value will change, set register regNewRowid to
+  ** contain the new value. If the rowid is not being modified,
+  ** then regNewRowid is the same register as regOldRowid, which is
+  ** already populated.  */
+  assert( chngKey || pTrigger || hasFK || regOldRowid==regNewRowid );
+  if( chngRowid ){
+    assert( iRowidExpr>=0 );
+    if( nChangeFrom==0 ){
+      sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_Column, iEph, iRowidExpr, regNewRowid);
+    }
+    sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid); VdbeCoverage(v);
+  }
+
+  /* Compute the old pre-UPDATE content of the row being changed, if that
+  ** information is needed */
+  if( chngPk || hasFK || pTrigger ){
+    u32 oldmask = (hasFK ? sqlite3FkOldmask(pParse, pTab) : 0);
+    oldmask |= sqlite3TriggerColmask(pParse,
+        pTrigger, pChanges, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onError
+    );
+    for(i=0; i<pTab->nCol; i++){
+      u32 colFlags = pTab->aCol[i].colFlags;
+      k = sqlite3TableColumnToStorage(pTab, i) + regOld;
+      if( oldmask==0xffffffff
+       || (i<32 && (oldmask & MASKBIT32(i))!=0)
+       || (colFlags & COLFLAG_PRIMKEY)!=0
+      ){
+        testcase(  oldmask!=0xffffffff && i==31 );
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, k);
+      }
+    }
+    if( chngRowid==0 && pPk==0 ){
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+      if( isView ) sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
+#endif
+      sqlite3VdbeAddOp2(v, OP_Copy, regOldRowid, regNewRowid);
+    }
+  }
+
+  /* Populate the array of registers beginning at regNew with the new
+  ** row data. This array is used to check constants, create the new
+  ** table and index records, and as the values for any new.* references
+  ** made by triggers.
+  **
+  ** If there are one or more BEFORE triggers, then do not populate the
+  ** registers associated with columns that are (a) not modified by
+  ** this UPDATE statement and (b) not accessed by new.* references. The
+  ** values for registers not modified by the UPDATE must be reloaded from
+  ** the database after the BEFORE triggers are fired anyway (as the trigger
+  ** may have modified them). So not loading those that are not going to
+  ** be used eliminates some redundant opcodes.
+  */
+  newmask = sqlite3TriggerColmask(
+      pParse, pTrigger, pChanges, 1, TRIGGER_BEFORE, pTab, onError
+  );
+  for(i=0, k=regNew; i<pTab->nCol; i++, k++){
+    if( i==pTab->iPKey ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, k);
+    }else if( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)!=0 ){
+      if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ) k--;
+    }else{
+      j = aXRef[i];
+      if( j>=0 ){
+        if( nChangeFrom ){
+          int nOff = (isView ? pTab->nCol : nPk);
+          assert( eOnePass==ONEPASS_OFF );
+          sqlite3VdbeAddOp3(v, OP_Column, iEph, nOff+j, k);
+        }else{
+          sqlite3ExprCode(pParse, pChanges->a[j].pExpr, k);
+        }
+      }else if( 0==(tmask&TRIGGER_BEFORE) || i>31 || (newmask & MASKBIT32(i)) ){
+        /* This branch loads the value of a column that will not be changed
+        ** into a register. This is done if there are no BEFORE triggers, or
+        ** if there are one or more BEFORE triggers that use this value via
+        ** a new.* reference in a trigger program.
+        */
+        testcase( i==31 );
+        testcase( i==32 );
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
+        bFinishSeek = 0;
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Null, 0, k);
+      }
+    }
+  }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  if( pTab->tabFlags & TF_HasGenerated ){
+    testcase( pTab->tabFlags & TF_HasVirtual );
+    testcase( pTab->tabFlags & TF_HasStored );
+    sqlite3ComputeGeneratedColumns(pParse, regNew, pTab);
+  }
+#endif
+
+  /* Fire any BEFORE UPDATE triggers. This happens before constraints are
+  ** verified. One could argue that this is wrong.
+  */
+  if( tmask&TRIGGER_BEFORE ){
+    sqlite3TableAffinity(v, pTab, regNew);
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
+        TRIGGER_BEFORE, pTab, regOldRowid, onError, labelContinue);
+
+    if( !isView ){
+      /* The row-trigger may have deleted the row being updated. In this
+      ** case, jump to the next row. No updates or AFTER triggers are
+      ** required. This behavior - what happens when the row being updated
+      ** is deleted or renamed by a BEFORE trigger - is left undefined in the
+      ** documentation.
+      */
+      if( pPk ){
+        sqlite3VdbeAddOp4Int(v, OP_NotFound,iDataCur,labelContinue,regKey,nKey);
+        VdbeCoverage(v);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue,regOldRowid);
+        VdbeCoverage(v);
+      }
+
+      /* After-BEFORE-trigger-reload-loop:
+      ** If it did not delete it, the BEFORE trigger may still have modified
+      ** some of the columns of the row being updated. Load the values for
+      ** all columns not modified by the update statement into their registers
+      ** in case this has happened. Only unmodified columns are reloaded.
+      ** The values computed for modified columns use the values before the
+      ** BEFORE trigger runs.  See test case trigger1-18.0 (added 2018-04-26)
+      ** for an example.
+      */
+      for(i=0, k=regNew; i<pTab->nCol; i++, k++){
+        if( pTab->aCol[i].colFlags & COLFLAG_GENERATED ){
+          if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ) k--;
+        }else if( aXRef[i]<0 && i!=pTab->iPKey ){
+          sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
+        }
+      }
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+      if( pTab->tabFlags & TF_HasGenerated ){
+        testcase( pTab->tabFlags & TF_HasVirtual );
+        testcase( pTab->tabFlags & TF_HasStored );
+        sqlite3ComputeGeneratedColumns(pParse, regNew, pTab);
+      }
+#endif
+    }
+  }
+
+  if( !isView ){
+    /* Do constraint checks. */
+    assert( regOldRowid>0 );
+    sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
+        regNewRowid, regOldRowid, chngKey, onError, labelContinue, &bReplace,
+        aXRef, 0);
+
+    /* If REPLACE conflict handling may have been used, or if the PK of the
+    ** row is changing, then the GenerateConstraintChecks() above may have
+    ** moved cursor iDataCur. Reseek it. */
+    if( bReplace || chngKey ){
+      if( pPk ){
+        sqlite3VdbeAddOp4Int(v, OP_NotFound,iDataCur,labelContinue,regKey,nKey);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue,regOldRowid);
+      }
+      VdbeCoverage(v);
+    }
+
+    /* Do FK constraint checks. */
+    if( hasFK ){
+      sqlite3FkCheck(pParse, pTab, regOldRowid, 0, aXRef, chngKey);
+    }
+
+    /* Delete the index entries associated with the current record.  */
+    sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur, aRegIdx, -1);
+
+    /* We must run the OP_FinishSeek opcode to resolve a prior
+    ** OP_DeferredSeek if there is any possibility that there have been
+    ** no OP_Column opcodes since the OP_DeferredSeek was issued.  But
+    ** we want to avoid the OP_FinishSeek if possible, as running it
+    ** costs CPU cycles. */
+    if( bFinishSeek ){
+      sqlite3VdbeAddOp1(v, OP_FinishSeek, iDataCur);
+    }
+
+    /* If changing the rowid value, or if there are foreign key constraints
+    ** to process, delete the old record. Otherwise, add a noop OP_Delete
+    ** to invoke the pre-update hook.
+    **
+    ** That (regNew==regnewRowid+1) is true is also important for the
+    ** pre-update hook. If the caller invokes preupdate_new(), the returned
+    ** value is copied from memory cell (regNewRowid+1+iCol), where iCol
+    ** is the column index supplied by the user.
+    */
+    assert( regNew==regNewRowid+1 );
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+    sqlite3VdbeAddOp3(v, OP_Delete, iDataCur,
+        OPFLAG_ISUPDATE | ((hasFK>1 || chngKey) ? 0 : OPFLAG_ISNOOP),
+        regNewRowid
+    );
+    if( eOnePass==ONEPASS_MULTI ){
+      assert( hasFK==0 && chngKey==0 );
+      sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION);
+    }
+    if( !pParse->nested ){
+      sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
+    }
+#else
+    if( hasFK>1 || chngKey ){
+      sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, 0);
+    }
+#endif
+
+    if( hasFK ){
+      sqlite3FkCheck(pParse, pTab, 0, regNewRowid, aXRef, chngKey);
+    }
+
+    /* Insert the new index entries and the new record. */
+    sqlite3CompleteInsertion(
+        pParse, pTab, iDataCur, iIdxCur, regNewRowid, aRegIdx,
+        OPFLAG_ISUPDATE | (eOnePass==ONEPASS_MULTI ? OPFLAG_SAVEPOSITION : 0),
+        0, 0
+    );
+
+    /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
+    ** handle rows (possibly in other tables) that refer via a foreign key
+    ** to the row just updated. */
+    if( hasFK ){
+      sqlite3FkActions(pParse, pTab, pChanges, regOldRowid, aXRef, chngKey);
+    }
+  }
+
+  /* Increment the row counter
+  */
+  if( regRowCount ){
+    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
+  }
+
+  if( pTrigger ){
+    sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
+        TRIGGER_AFTER, pTab, regOldRowid, onError, labelContinue);
+  }
+
+  /* Repeat the above with the next record to be updated, until
+  ** all record selected by the WHERE clause have been updated.
+  */
+  if( eOnePass==ONEPASS_SINGLE ){
+    /* Nothing to do at end-of-loop for a single-pass */
+  }else if( eOnePass==ONEPASS_MULTI ){
+    sqlite3VdbeResolveLabel(v, labelContinue);
+    sqlite3WhereEnd(pWInfo);
+  }else{
+    sqlite3VdbeResolveLabel(v, labelContinue);
+    sqlite3VdbeAddOp2(v, OP_Next, iEph, addrTop); VdbeCoverage(v);
+  }
+  sqlite3VdbeResolveLabel(v, labelBreak);
+
+  /* Update the sqlite_sequence table by storing the content of the
+  ** maximum rowid counter values recorded while inserting into
+  ** autoincrement tables.
+  */
+  if( pParse->nested==0 && pParse->pTriggerTab==0 && pUpsert==0 ){
+    sqlite3AutoincrementEnd(pParse);
+  }
+
+  /*
+  ** Return the number of rows that were changed, if we are tracking
+  ** that information.
+  */
+  if( regRowCount ){
+    sqlite3CodeChangeCount(v, regRowCount, "rows updated");
+  }
+
+update_cleanup:
+  sqlite3AuthContextPop(&sContext);
+  sqlite3DbFree(db, aXRef); /* Also frees aRegIdx[] and aToOpen[] */
+  sqlite3SrcListDelete(db, pTabList);
+  sqlite3ExprListDelete(db, pChanges);
+  sqlite3ExprDelete(db, pWhere);
+#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT)
+  sqlite3ExprListDelete(db, pOrderBy);
+  sqlite3ExprDelete(db, pLimit);
+#endif
+  return;
+}
+/* Make sure "isView" and other macros defined above are undefined. Otherwise
+** they may interfere with compilation of other functions in this file
+** (or in another file, if this file becomes part of the amalgamation).  */
+#ifdef isView
+ #undef isView
+#endif
+#ifdef pTrigger
+ #undef pTrigger
+#endif
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Generate code for an UPDATE of a virtual table.
+**
+** There are two possible strategies - the default and the special
+** "onepass" strategy. Onepass is only used if the virtual table
+** implementation indicates that pWhere may match at most one row.
+**
+** The default strategy is to create an ephemeral table that contains
+** for each row to be changed:
+**
+**   (A)  The original rowid of that row.
+**   (B)  The revised rowid for the row.
+**   (C)  The content of every column in the row.
+**
+** Then loop through the contents of this ephemeral table executing a
+** VUpdate for each row. When finished, drop the ephemeral table.
+**
+** The "onepass" strategy does not use an ephemeral table. Instead, it
+** stores the same values (A, B and C above) in a register array and
+** makes a single invocation of VUpdate.
+*/
+static void updateVirtualTable(
+  Parse *pParse,       /* The parsing context */
+  SrcList *pSrc,       /* The virtual table to be modified */
+  Table *pTab,         /* The virtual table */
+  ExprList *pChanges,  /* The columns to change in the UPDATE statement */
+  Expr *pRowid,        /* Expression used to recompute the rowid */
+  int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
+  Expr *pWhere,        /* WHERE clause of the UPDATE statement */
+  int onError          /* ON CONFLICT strategy */
+){
+  Vdbe *v = pParse->pVdbe;  /* Virtual machine under construction */
+  int ephemTab;             /* Table holding the result of the SELECT */
+  int i;                    /* Loop counter */
+  sqlite3 *db = pParse->db; /* Database connection */
+  const char *pVTab = (const char*)sqlite3GetVTable(db, pTab);
+  WhereInfo *pWInfo = 0;
+  int nArg = 2 + pTab->nCol;      /* Number of arguments to VUpdate */
+  int regArg;                     /* First register in VUpdate arg array */
+  int regRec;                     /* Register in which to assemble record */
+  int regRowid;                   /* Register for ephemeral table rowid */
+  int iCsr = pSrc->a[0].iCursor;  /* Cursor used for virtual table scan */
+  int aDummy[2];                  /* Unused arg for sqlite3WhereOkOnePass() */
+  int eOnePass;                   /* True to use onepass strategy */
+  int addr;                       /* Address of OP_OpenEphemeral */
+
+  /* Allocate nArg registers in which to gather the arguments for VUpdate. Then
+  ** create and open the ephemeral table in which the records created from
+  ** these arguments will be temporarily stored. */
+  assert( v );
+  ephemTab = pParse->nTab++;
+  addr= sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, nArg);
+  regArg = pParse->nMem + 1;
+  pParse->nMem += nArg;
+  if( pSrc->nSrc>1 ){
+    Index *pPk = 0;
+    Expr *pRow;
+    ExprList *pList;
+    if( HasRowid(pTab) ){
+      if( pRowid ){
+        pRow = sqlite3ExprDup(db, pRowid, 0);
+      }else{
+        pRow = sqlite3PExpr(pParse, TK_ROW, 0, 0);
+      }
+    }else{
+      i16 iPk;      /* PRIMARY KEY column */
+      pPk = sqlite3PrimaryKeyIndex(pTab);
+      assert( pPk!=0 );
+      assert( pPk->nKeyCol==1 );
+      iPk = pPk->aiColumn[0];
+      if( aXRef[iPk]>=0 ){
+        pRow = sqlite3ExprDup(db, pChanges->a[aXRef[iPk]].pExpr, 0);
+      }else{
+        pRow = exprRowColumn(pParse, iPk);
+      }
+    }
+    pList = sqlite3ExprListAppend(pParse, 0, pRow);
+
+    for(i=0; i<pTab->nCol; i++){
+      if( aXRef[i]>=0 ){
+        pList = sqlite3ExprListAppend(pParse, pList,
+          sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr, 0)
+        );
+      }else{
+        Expr *pRowExpr = exprRowColumn(pParse, i);
+        if( pRowExpr ) pRowExpr->op2 = OPFLAG_NOCHNG;
+        pList = sqlite3ExprListAppend(pParse, pList, pRowExpr);
+      }
+    }
+
+    updateFromSelect(pParse, ephemTab, pPk, pList, pSrc, pWhere, 0, 0);
+    sqlite3ExprListDelete(db, pList);
+    eOnePass = ONEPASS_OFF;
+  }else{
+    regRec = ++pParse->nMem;
+    regRowid = ++pParse->nMem;
+
+    /* Start scanning the virtual table */
+    pWInfo = sqlite3WhereBegin(
+        pParse, pSrc, pWhere, 0, 0, 0, WHERE_ONEPASS_DESIRED, 0
+    );
+    if( pWInfo==0 ) return;
+
+    /* Populate the argument registers. */
+    for(i=0; i<pTab->nCol; i++){
+      assert( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)==0 );
+      if( aXRef[i]>=0 ){
+        sqlite3ExprCode(pParse, pChanges->a[aXRef[i]].pExpr, regArg+2+i);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_VColumn, iCsr, i, regArg+2+i);
+        sqlite3VdbeChangeP5(v, OPFLAG_NOCHNG);/* For sqlite3_vtab_nochange() */
+      }
+    }
+    if( HasRowid(pTab) ){
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg);
+      if( pRowid ){
+        sqlite3ExprCode(pParse, pRowid, regArg+1);
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg+1);
+      }
+    }else{
+      Index *pPk;   /* PRIMARY KEY index */
+      i16 iPk;      /* PRIMARY KEY column */
+      pPk = sqlite3PrimaryKeyIndex(pTab);
+      assert( pPk!=0 );
+      assert( pPk->nKeyCol==1 );
+      iPk = pPk->aiColumn[0];
+      sqlite3VdbeAddOp3(v, OP_VColumn, iCsr, iPk, regArg);
+      sqlite3VdbeAddOp2(v, OP_SCopy, regArg+2+iPk, regArg+1);
+    }
+
+    eOnePass = sqlite3WhereOkOnePass(pWInfo, aDummy);
+
+    /* There is no ONEPASS_MULTI on virtual tables */
+    assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE );
+
+    if( eOnePass ){
+      /* If using the onepass strategy, no-op out the OP_OpenEphemeral coded
+      ** above. */
+      sqlite3VdbeChangeToNoop(v, addr);
+      sqlite3VdbeAddOp1(v, OP_Close, iCsr);
+    }else{
+      /* Create a record from the argument register contents and insert it into
+      ** the ephemeral table. */
+      sqlite3MultiWrite(pParse);
+      sqlite3VdbeAddOp3(v, OP_MakeRecord, regArg, nArg, regRec);
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_ENABLE_NULL_TRIM)
+      /* Signal an assert() within OP_MakeRecord that it is allowed to
+      ** accept no-change records with serial_type 10 */
+      sqlite3VdbeChangeP5(v, OPFLAG_NOCHNG_MAGIC);
+#endif
+      sqlite3VdbeAddOp2(v, OP_NewRowid, ephemTab, regRowid);
+      sqlite3VdbeAddOp3(v, OP_Insert, ephemTab, regRec, regRowid);
+    }
+  }
+
+
+  if( eOnePass==ONEPASS_OFF ){
+    /* End the virtual table scan */
+    if( pSrc->nSrc==1 ){
+      sqlite3WhereEnd(pWInfo);
+    }
+
+    /* Begin scanning through the ephemeral table. */
+    addr = sqlite3VdbeAddOp1(v, OP_Rewind, ephemTab); VdbeCoverage(v);
+
+    /* Extract arguments from the current row of the ephemeral table and
+    ** invoke the VUpdate method.  */
+    for(i=0; i<nArg; i++){
+      sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i, regArg+i);
+    }
+  }
+  sqlite3VtabMakeWritable(pParse, pTab);
+  sqlite3VdbeAddOp4(v, OP_VUpdate, 0, nArg, regArg, pVTab, P4_VTAB);
+  sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
+  sqlite3MayAbort(pParse);
+
+  /* End of the ephemeral table scan. Or, if using the onepass strategy,
+  ** jump to here if the scan visited zero rows. */
+  if( eOnePass==ONEPASS_OFF ){
+    sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr);
+    sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
+  }else{
+    sqlite3WhereEnd(pWInfo);
+  }
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/************** End of update.c **********************************************/
+/************** Begin file upsert.c ******************************************/
+/*
+** 2018-04-12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code to implement various aspects of UPSERT
+** processing and handling of the Upsert object.
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_UPSERT
+/*
+** Free a list of Upsert objects
+*/
+static void SQLITE_NOINLINE upsertDelete(sqlite3 *db, Upsert *p){
+  do{
+    Upsert *pNext = p->pNextUpsert;
+    sqlite3ExprListDelete(db, p->pUpsertTarget);
+    sqlite3ExprDelete(db, p->pUpsertTargetWhere);
+    sqlite3ExprListDelete(db, p->pUpsertSet);
+    sqlite3ExprDelete(db, p->pUpsertWhere);
+    sqlite3DbFree(db, p->pToFree);
+    sqlite3DbFree(db, p);
+    p = pNext;
+  }while( p );
+}
+SQLITE_PRIVATE void sqlite3UpsertDelete(sqlite3 *db, Upsert *p){
+  if( p ) upsertDelete(db, p);
+}
+
+
+/*
+** Duplicate an Upsert object.
+*/
+SQLITE_PRIVATE Upsert *sqlite3UpsertDup(sqlite3 *db, Upsert *p){
+  if( p==0 ) return 0;
+  return sqlite3UpsertNew(db,
+           sqlite3ExprListDup(db, p->pUpsertTarget, 0),
+           sqlite3ExprDup(db, p->pUpsertTargetWhere, 0),
+           sqlite3ExprListDup(db, p->pUpsertSet, 0),
+           sqlite3ExprDup(db, p->pUpsertWhere, 0),
+           sqlite3UpsertDup(db, p->pNextUpsert)
+         );
+}
+
+/*
+** Create a new Upsert object.
+*/
+SQLITE_PRIVATE Upsert *sqlite3UpsertNew(
+  sqlite3 *db,           /* Determines which memory allocator to use */
+  ExprList *pTarget,     /* Target argument to ON CONFLICT, or NULL */
+  Expr *pTargetWhere,    /* Optional WHERE clause on the target */
+  ExprList *pSet,        /* UPDATE columns, or NULL for a DO NOTHING */
+  Expr *pWhere,          /* WHERE clause for the ON CONFLICT UPDATE */
+  Upsert *pNext          /* Next ON CONFLICT clause in the list */
+){
+  Upsert *pNew;
+  pNew = sqlite3DbMallocZero(db, sizeof(Upsert));
+  if( pNew==0 ){
+    sqlite3ExprListDelete(db, pTarget);
+    sqlite3ExprDelete(db, pTargetWhere);
+    sqlite3ExprListDelete(db, pSet);
+    sqlite3ExprDelete(db, pWhere);
+    sqlite3UpsertDelete(db, pNext);
+    return 0;
+  }else{
+    pNew->pUpsertTarget = pTarget;
+    pNew->pUpsertTargetWhere = pTargetWhere;
+    pNew->pUpsertSet = pSet;
+    pNew->pUpsertWhere = pWhere;
+    pNew->isDoUpdate = pSet!=0;
+    pNew->pNextUpsert = pNext;
+  }
+  return pNew;
+}
+
+/*
+** Analyze the ON CONFLICT clause described by pUpsert.  Resolve all
+** symbols in the conflict-target.
+**
+** Return SQLITE_OK if everything works, or an error code is something
+** is wrong.
+*/
+SQLITE_PRIVATE int sqlite3UpsertAnalyzeTarget(
+  Parse *pParse,     /* The parsing context */
+  SrcList *pTabList, /* Table into which we are inserting */
+  Upsert *pUpsert,   /* The ON CONFLICT clauses */
+  Upsert *pAll       /* Complete list of all ON CONFLICT clauses */
+){
+  Table *pTab;            /* That table into which we are inserting */
+  int rc;                 /* Result code */
+  int iCursor;            /* Cursor used by pTab */
+  Index *pIdx;            /* One of the indexes of pTab */
+  ExprList *pTarget;      /* The conflict-target clause */
+  Expr *pTerm;            /* One term of the conflict-target clause */
+  NameContext sNC;        /* Context for resolving symbolic names */
+  Expr sCol[2];           /* Index column converted into an Expr */
+  int nClause = 0;        /* Counter of ON CONFLICT clauses */
+
+  assert( pTabList->nSrc==1 );
+  assert( pTabList->a[0].pSTab!=0 );
+  assert( pUpsert!=0 );
+  assert( pUpsert->pUpsertTarget!=0 );
+
+  /* Resolve all symbolic names in the conflict-target clause, which
+  ** includes both the list of columns and the optional partial-index
+  ** WHERE clause.
+  */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  sNC.pSrcList = pTabList;
+  for(; pUpsert && pUpsert->pUpsertTarget;
+        pUpsert=pUpsert->pNextUpsert, nClause++){
+    rc = sqlite3ResolveExprListNames(&sNC, pUpsert->pUpsertTarget);
+    if( rc ) return rc;
+    rc = sqlite3ResolveExprNames(&sNC, pUpsert->pUpsertTargetWhere);
+    if( rc ) return rc;
+
+    /* Check to see if the conflict target matches the rowid. */
+    pTab = pTabList->a[0].pSTab;
+    pTarget = pUpsert->pUpsertTarget;
+    iCursor = pTabList->a[0].iCursor;
+    if( HasRowid(pTab)
+     && pTarget->nExpr==1
+     && (pTerm = pTarget->a[0].pExpr)->op==TK_COLUMN
+     && pTerm->iColumn==XN_ROWID
+    ){
+      /* The conflict-target is the rowid of the primary table */
+      assert( pUpsert->pUpsertIdx==0 );
+      continue;
+    }
+
+    /* Initialize sCol[0..1] to be an expression parse tree for a
+    ** single column of an index.  The sCol[0] node will be the TK_COLLATE
+    ** operator and sCol[1] will be the TK_COLUMN operator.  Code below
+    ** will populate the specific collation and column number values
+    ** prior to comparing against the conflict-target expression.
+    */
+    memset(sCol, 0, sizeof(sCol));
+    sCol[0].op = TK_COLLATE;
+    sCol[0].pLeft = &sCol[1];
+    sCol[1].op = TK_COLUMN;
+    sCol[1].iTable = pTabList->a[0].iCursor;
+
+    /* Check for matches against other indexes */
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      int ii, jj, nn;
+      if( !IsUniqueIndex(pIdx) ) continue;
+      if( pTarget->nExpr!=pIdx->nKeyCol ) continue;
+      if( pIdx->pPartIdxWhere ){
+        if( pUpsert->pUpsertTargetWhere==0 ) continue;
+        if( sqlite3ExprCompare(pParse, pUpsert->pUpsertTargetWhere,
+                               pIdx->pPartIdxWhere, iCursor)!=0 ){
+          continue;
+        }
+      }
+      nn = pIdx->nKeyCol;
+      for(ii=0; ii<nn; ii++){
+        Expr *pExpr;
+        sCol[0].u.zToken = (char*)pIdx->azColl[ii];
+        if( pIdx->aiColumn[ii]==XN_EXPR ){
+          assert( pIdx->aColExpr!=0 );
+          assert( pIdx->aColExpr->nExpr>ii );
+          assert( pIdx->bHasExpr );
+          pExpr = pIdx->aColExpr->a[ii].pExpr;
+          if( pExpr->op!=TK_COLLATE ){
+            sCol[0].pLeft = pExpr;
+            pExpr = &sCol[0];
+          }
+        }else{
+          sCol[0].pLeft = &sCol[1];
+          sCol[1].iColumn = pIdx->aiColumn[ii];
+          pExpr = &sCol[0];
+        }
+        for(jj=0; jj<nn; jj++){
+          if( sqlite3ExprCompare(0,pTarget->a[jj].pExpr,pExpr,iCursor)<2 ){
+            break;  /* Column ii of the index matches column jj of target */
+          }
+        }
+        if( jj>=nn ){
+          /* The target contains no match for column jj of the index */
+          break;
+        }
+      }
+      if( ii<nn ){
+        /* Column ii of the index did not match any term of the conflict target.
+        ** Continue the search with the next index. */
+        continue;
+      }
+      pUpsert->pUpsertIdx = pIdx;
+      if( sqlite3UpsertOfIndex(pAll,pIdx)!=pUpsert ){
+        /* Really this should be an error.  The isDup ON CONFLICT clause will
+        ** never fire.  But this problem was not discovered until three years
+        ** after multi-CONFLICT upsert was added, and so we silently ignore
+        ** the problem to prevent breaking applications that might actually
+        ** have redundant ON CONFLICT clauses. */
+        pUpsert->isDup = 1;
+      }
+      break;
+    }
+    if( pUpsert->pUpsertIdx==0 ){
+      char zWhich[16];
+      if( nClause==0 && pUpsert->pNextUpsert==0 ){
+        zWhich[0] = 0;
+      }else{
+        sqlite3_snprintf(sizeof(zWhich),zWhich,"%r ", nClause+1);
+      }
+      sqlite3ErrorMsg(pParse, "%sON CONFLICT clause does not match any "
+                              "PRIMARY KEY or UNIQUE constraint", zWhich);
+      return SQLITE_ERROR;
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return true if pUpsert is the last ON CONFLICT clause with a
+** conflict target, or if pUpsert is followed by another ON CONFLICT
+** clause that targets the INTEGER PRIMARY KEY.
+*/
+SQLITE_PRIVATE int sqlite3UpsertNextIsIPK(Upsert *pUpsert){
+  Upsert *pNext;
+  if( NEVER(pUpsert==0) ) return 0;
+  pNext = pUpsert->pNextUpsert;
+  while( 1 /*exit-by-return*/ ){
+    if( pNext==0 ) return 1;
+    if( pNext->pUpsertTarget==0 ) return 1;
+    if( pNext->pUpsertIdx==0 ) return 1;
+    if( !pNext->isDup ) return 0;
+    pNext = pNext->pNextUpsert;
+  }
+  return 0;
+}
+
+/*
+** Given the list of ON CONFLICT clauses described by pUpsert, and
+** a particular index pIdx, return a pointer to the particular ON CONFLICT
+** clause that applies to the index.  Or, if the index is not subject to
+** any ON CONFLICT clause, return NULL.
+*/
+SQLITE_PRIVATE Upsert *sqlite3UpsertOfIndex(Upsert *pUpsert, Index *pIdx){
+  while(
+      pUpsert
+   && pUpsert->pUpsertTarget!=0
+   && pUpsert->pUpsertIdx!=pIdx
+  ){
+     pUpsert = pUpsert->pNextUpsert;
+  }
+  return pUpsert;
+}
+
+/*
+** Generate bytecode that does an UPDATE as part of an upsert.
+**
+** If pIdx is NULL, then the UNIQUE constraint that failed was the IPK.
+** In this case parameter iCur is a cursor open on the table b-tree that
+** currently points to the conflicting table row. Otherwise, if pIdx
+** is not NULL, then pIdx is the constraint that failed and iCur is a
+** cursor points to the conflicting row.
+*/
+SQLITE_PRIVATE void sqlite3UpsertDoUpdate(
+  Parse *pParse,        /* The parsing and code-generating context */
+  Upsert *pUpsert,      /* The ON CONFLICT clause for the upsert */
+  Table *pTab,          /* The table being updated */
+  Index *pIdx,          /* The UNIQUE constraint that failed */
+  int iCur              /* Cursor for pIdx (or pTab if pIdx==NULL) */
+){
+  Vdbe *v = pParse->pVdbe;
+  sqlite3 *db = pParse->db;
+  SrcList *pSrc;            /* FROM clause for the UPDATE */
+  int iDataCur;
+  int i;
+  Upsert *pTop = pUpsert;
+
+  assert( v!=0 );
+  assert( pUpsert!=0 );
+  iDataCur = pUpsert->iDataCur;
+  pUpsert = sqlite3UpsertOfIndex(pTop, pIdx);
+  VdbeNoopComment((v, "Begin DO UPDATE of UPSERT"));
+  if( pIdx && iCur!=iDataCur ){
+    if( HasRowid(pTab) ){
+      int regRowid = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp2(v, OP_IdxRowid, iCur, regRowid);
+      sqlite3VdbeAddOp3(v, OP_SeekRowid, iDataCur, 0, regRowid);
+      VdbeCoverage(v);
+      sqlite3ReleaseTempReg(pParse, regRowid);
+    }else{
+      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+      int nPk = pPk->nKeyCol;
+      int iPk = pParse->nMem+1;
+      pParse->nMem += nPk;
+      for(i=0; i<nPk; i++){
+        int k;
+        assert( pPk->aiColumn[i]>=0 );
+        k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[i]);
+        sqlite3VdbeAddOp3(v, OP_Column, iCur, k, iPk+i);
+        VdbeComment((v, "%s.%s", pIdx->zName,
+                    pTab->aCol[pPk->aiColumn[i]].zCnName));
+      }
+      sqlite3VdbeVerifyAbortable(v, OE_Abort);
+      i = sqlite3VdbeAddOp4Int(v, OP_Found, iDataCur, 0, iPk, nPk);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CORRUPT, OE_Abort, 0,
+            "corrupt database", P4_STATIC);
+      sqlite3MayAbort(pParse);
+      sqlite3VdbeJumpHere(v, i);
+    }
+  }
+  /* pUpsert does not own pTop->pUpsertSrc - the outer INSERT statement does.
+  ** So we have to make a copy before passing it down into sqlite3Update() */
+  pSrc = sqlite3SrcListDup(db, pTop->pUpsertSrc, 0);
+  /* excluded.* columns of type REAL need to be converted to a hard real */
+  for(i=0; i<pTab->nCol; i++){
+    if( pTab->aCol[i].affinity==SQLITE_AFF_REAL ){
+      sqlite3VdbeAddOp1(v, OP_RealAffinity, pTop->regData+i);
+    }
+  }
+  sqlite3Update(pParse, pSrc, sqlite3ExprListDup(db,pUpsert->pUpsertSet,0),
+      sqlite3ExprDup(db,pUpsert->pUpsertWhere,0), OE_Abort, 0, 0, pUpsert);
+  VdbeNoopComment((v, "End DO UPDATE of UPSERT"));
+}
+
+#endif /* SQLITE_OMIT_UPSERT */
+
+/************** End of upsert.c **********************************************/
+/************** Begin file vacuum.c ******************************************/
+/*
+** 2003 April 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to implement the VACUUM command.
+**
+** Most of the code in this file may be omitted by defining the
+** SQLITE_OMIT_VACUUM macro.
+*/
+/* #include "sqliteInt.h" */
+/* #include "vdbeInt.h" */
+
+#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
+
+/*
+** Execute zSql on database db.
+**
+** If zSql returns rows, then each row will have exactly one
+** column.  (This will only happen if zSql begins with "SELECT".)
+** Take each row of result and call execSql() again recursively.
+**
+** The execSqlF() routine does the same thing, except it accepts
+** a format string as its third argument
+*/
+static int execSql(sqlite3 *db, char **pzErrMsg, const char *zSql){
+  sqlite3_stmt *pStmt;
+  int rc;
+
+  /* printf("SQL: [%s]\n", zSql); fflush(stdout); */
+  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  while( SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
+    const char *zSubSql = (const char*)sqlite3_column_text(pStmt,0);
+    assert( sqlite3_strnicmp(zSql,"SELECT",6)==0 );
+    /* The secondary SQL must be one of CREATE TABLE, CREATE INDEX,
+    ** or INSERT.  Historically there have been attacks that first
+    ** corrupt the sqlite_schema.sql field with other kinds of statements
+    ** then run VACUUM to get those statements to execute at inappropriate
+    ** times. */
+    if( zSubSql
+     && (strncmp(zSubSql,"CRE",3)==0 || strncmp(zSubSql,"INS",3)==0)
+    ){
+      rc = execSql(db, pzErrMsg, zSubSql);
+      if( rc!=SQLITE_OK ) break;
+    }
+  }
+  assert( rc!=SQLITE_ROW );
+  if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  if( rc ){
+    sqlite3SetString(pzErrMsg, db, sqlite3_errmsg(db));
+  }
+  (void)sqlite3_finalize(pStmt);
+  return rc;
+}
+static int execSqlF(sqlite3 *db, char **pzErrMsg, const char *zSql, ...){
+  char *z;
+  va_list ap;
+  int rc;
+  va_start(ap, zSql);
+  z = sqlite3VMPrintf(db, zSql, ap);
+  va_end(ap);
+  if( z==0 ) return SQLITE_NOMEM;
+  rc = execSql(db, pzErrMsg, z);
+  sqlite3DbFree(db, z);
+  return rc;
+}
+
+/*
+** The VACUUM command is used to clean up the database,
+** collapse free space, etc.  It is modelled after the VACUUM command
+** in PostgreSQL.  The VACUUM command works as follows:
+**
+**   (1)  Create a new transient database file
+**   (2)  Copy all content from the database being vacuumed into
+**        the new transient database file
+**   (3)  Copy content from the transient database back into the
+**        original database.
+**
+** The transient database requires temporary disk space approximately
+** equal to the size of the original database.  The copy operation of
+** step (3) requires additional temporary disk space approximately equal
+** to the size of the original database for the rollback journal.
+** Hence, temporary disk space that is approximately 2x the size of the
+** original database is required.  Every page of the database is written
+** approximately 3 times:  Once for step (2) and twice for step (3).
+** Two writes per page are required in step (3) because the original
+** database content must be written into the rollback journal prior to
+** overwriting the database with the vacuumed content.
+**
+** Only 1x temporary space and only 1x writes would be required if
+** the copy of step (3) were replaced by deleting the original database
+** and renaming the transient database as the original.  But that will
+** not work if other processes are attached to the original database.
+** And a power loss in between deleting the original and renaming the
+** transient would cause the database file to appear to be deleted
+** following reboot.
+*/
+SQLITE_PRIVATE void sqlite3Vacuum(Parse *pParse, Token *pNm, Expr *pInto){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int iDb = 0;
+  if( v==0 ) goto build_vacuum_end;
+  if( pParse->nErr ) goto build_vacuum_end;
+  if( pNm ){
+#ifndef SQLITE_BUG_COMPATIBLE_20160819
+    /* Default behavior:  Report an error if the argument to VACUUM is
+    ** not recognized */
+    iDb = sqlite3TwoPartName(pParse, pNm, pNm, &pNm);
+    if( iDb<0 ) goto build_vacuum_end;
+#else
+    /* When SQLITE_BUG_COMPATIBLE_20160819 is defined, unrecognized arguments
+    ** to VACUUM are silently ignored.  This is a back-out of a bug fix that
+    ** occurred on 2016-08-19 (https://www.sqlite.org/src/info/083f9e6270).
+    ** The buggy behavior is required for binary compatibility with some
+    ** legacy applications. */
+    iDb = sqlite3FindDb(pParse->db, pNm);
+    if( iDb<0 ) iDb = 0;
+#endif
+  }
+  if( iDb!=1 ){
+    int iIntoReg = 0;
+    if( pInto && sqlite3ResolveSelfReference(pParse,0,0,pInto,0)==0 ){
+      iIntoReg = ++pParse->nMem;
+      sqlite3ExprCode(pParse, pInto, iIntoReg);
+    }
+    sqlite3VdbeAddOp2(v, OP_Vacuum, iDb, iIntoReg);
+    sqlite3VdbeUsesBtree(v, iDb);
+  }
+build_vacuum_end:
+  sqlite3ExprDelete(pParse->db, pInto);
+  return;
+}
+
+/*
+** This routine implements the OP_Vacuum opcode of the VDBE.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE int sqlite3RunVacuum(
+  char **pzErrMsg,        /* Write error message here */
+  sqlite3 *db,            /* Database connection */
+  int iDb,                /* Which attached DB to vacuum */
+  sqlite3_value *pOut     /* Write results here, if not NULL. VACUUM INTO */
+){
+  int rc = SQLITE_OK;     /* Return code from service routines */
+  Btree *pMain;           /* The database being vacuumed */
+  Btree *pTemp;           /* The temporary database we vacuum into */
+  u32 saved_mDbFlags;     /* Saved value of db->mDbFlags */
+  u64 saved_flags;        /* Saved value of db->flags */
+  i64 saved_nChange;      /* Saved value of db->nChange */
+  i64 saved_nTotalChange; /* Saved value of db->nTotalChange */
+  u32 saved_openFlags;    /* Saved value of db->openFlags */
+  u8 saved_mTrace;        /* Saved trace settings */
+  Db *pDb = 0;            /* Database to detach at end of vacuum */
+  int isMemDb;            /* True if vacuuming a :memory: database */
+  int nRes;               /* Bytes of reserved space at the end of each page */
+  int nDb;                /* Number of attached databases */
+  const char *zDbMain;    /* Schema name of database to vacuum */
+  const char *zOut;       /* Name of output file */
+  u32 pgflags = PAGER_SYNCHRONOUS_OFF; /* sync flags for output db */
+  u64 iRandom;            /* Random value used for zDbVacuum[] */
+  char zDbVacuum[42];     /* Name of the ATTACH-ed database used for vacuum */
+
+
+  if( !db->autoCommit ){
+    sqlite3SetString(pzErrMsg, db, "cannot VACUUM from within a transaction");
+    return SQLITE_ERROR; /* IMP: R-12218-18073 */
+  }
+  if( db->nVdbeActive>1 ){
+    sqlite3SetString(pzErrMsg, db,"cannot VACUUM - SQL statements in progress");
+    return SQLITE_ERROR; /* IMP: R-15610-35227 */
+  }
+  saved_openFlags = db->openFlags;
+  if( pOut ){
+    if( sqlite3_value_type(pOut)!=SQLITE_TEXT ){
+      sqlite3SetString(pzErrMsg, db, "non-text filename");
+      return SQLITE_ERROR;
+    }
+    zOut = (const char*)sqlite3_value_text(pOut);
+    db->openFlags &= ~SQLITE_OPEN_READONLY;
+    db->openFlags |= SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE;
+  }else{
+    zOut = "";
+  }
+
+  /* Save the current value of the database flags so that it can be
+  ** restored before returning. Then set the writable-schema flag, and
+  ** disable CHECK and foreign key constraints.  */
+  saved_flags = db->flags;
+  saved_mDbFlags = db->mDbFlags;
+  saved_nChange = db->nChange;
+  saved_nTotalChange = db->nTotalChange;
+  saved_mTrace = db->mTrace;
+  db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks;
+  db->mDbFlags |= DBFLAG_PreferBuiltin | DBFLAG_Vacuum;
+  db->flags &= ~(u64)(SQLITE_ForeignKeys | SQLITE_ReverseOrder
+                   | SQLITE_Defensive | SQLITE_CountRows);
+  db->mTrace = 0;
+
+  zDbMain = db->aDb[iDb].zDbSName;
+  pMain = db->aDb[iDb].pBt;
+  isMemDb = sqlite3PagerIsMemdb(sqlite3BtreePager(pMain));
+
+  /* Attach the temporary database as 'vacuum_XXXXXX'. The synchronous pragma
+  ** can be set to 'off' for this file, as it is not recovered if a crash
+  ** occurs anyway. The integrity of the database is maintained by a
+  ** (possibly synchronous) transaction opened on the main database before
+  ** sqlite3BtreeCopyFile() is called.
+  **
+  ** An optimization would be to use a non-journaled pager.
+  ** (Later:) I tried setting "PRAGMA vacuum_XXXXXX.journal_mode=OFF" but
+  ** that actually made the VACUUM run slower.  Very little journalling
+  ** actually occurs when doing a vacuum since the vacuum_db is initially
+  ** empty.  Only the journal header is written.  Apparently it takes more
+  ** time to parse and run the PRAGMA to turn journalling off than it does
+  ** to write the journal header file.
+  */
+  sqlite3_randomness(sizeof(iRandom),&iRandom);
+  sqlite3_snprintf(sizeof(zDbVacuum), zDbVacuum, "vacuum_%016llx", iRandom);
+  nDb = db->nDb;
+  rc = execSqlF(db, pzErrMsg, "ATTACH %Q AS %s", zOut, zDbVacuum);
+  db->openFlags = saved_openFlags;
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  assert( (db->nDb-1)==nDb );
+  pDb = &db->aDb[nDb];
+  assert( strcmp(pDb->zDbSName,zDbVacuum)==0 );
+  pTemp = pDb->pBt;
+  if( pOut ){
+    sqlite3_file *id = sqlite3PagerFile(sqlite3BtreePager(pTemp));
+    i64 sz = 0;
+    if( id->pMethods!=0 && (sqlite3OsFileSize(id, &sz)!=SQLITE_OK || sz>0) ){
+      rc = SQLITE_ERROR;
+      sqlite3SetString(pzErrMsg, db, "output file already exists");
+      goto end_of_vacuum;
+    }
+    db->mDbFlags |= DBFLAG_VacuumInto;
+
+    /* For a VACUUM INTO, the pager-flags are set to the same values as
+    ** they are for the database being vacuumed, except that PAGER_CACHESPILL
+    ** is always set. */
+    pgflags = db->aDb[iDb].safety_level | (db->flags & PAGER_FLAGS_MASK);
+  }
+  nRes = sqlite3BtreeGetRequestedReserve(pMain);
+
+  sqlite3BtreeSetCacheSize(pTemp, db->aDb[iDb].pSchema->cache_size);
+  sqlite3BtreeSetSpillSize(pTemp, sqlite3BtreeSetSpillSize(pMain,0));
+  sqlite3BtreeSetPagerFlags(pTemp, pgflags|PAGER_CACHESPILL);
+
+  /* Begin a transaction and take an exclusive lock on the main database
+  ** file. This is done before the sqlite3BtreeGetPageSize(pMain) call below,
+  ** to ensure that we do not try to change the page-size on a WAL database.
+  */
+  rc = execSql(db, pzErrMsg, "BEGIN");
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = sqlite3BtreeBeginTrans(pMain, pOut==0 ? 2 : 0, 0);
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Do not attempt to change the page size for a WAL database */
+  if( sqlite3PagerGetJournalMode(sqlite3BtreePager(pMain))
+                                               ==PAGER_JOURNALMODE_WAL
+   && pOut==0
+  ){
+    db->nextPagesize = 0;
+  }
+
+  if( sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes, 0)
+   || (!isMemDb && sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes, 0))
+   || NEVER(db->mallocFailed)
+  ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto end_of_vacuum;
+  }
+
+#ifndef SQLITE_OMIT_AUTOVACUUM
+  sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac>=0 ? db->nextAutovac :
+                                           sqlite3BtreeGetAutoVacuum(pMain));
+#endif
+
+  /* Query the schema of the main database. Create a mirror schema
+  ** in the temporary database.
+  */
+  db->init.iDb = nDb; /* force new CREATE statements into vacuum_db */
+  rc = execSqlF(db, pzErrMsg,
+      "SELECT sql FROM \"%w\".sqlite_schema"
+      " WHERE type='table'AND name<>'sqlite_sequence'"
+      " AND coalesce(rootpage,1)>0",
+      zDbMain
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  rc = execSqlF(db, pzErrMsg,
+      "SELECT sql FROM \"%w\".sqlite_schema"
+      " WHERE type='index'",
+      zDbMain
+  );
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+  db->init.iDb = 0;
+
+  /* Loop through the tables in the main database. For each, do
+  ** an "INSERT INTO vacuum_db.xxx SELECT * FROM main.xxx;" to copy
+  ** the contents to the temporary database.
+  */
+  rc = execSqlF(db, pzErrMsg,
+      "SELECT'INSERT INTO %s.'||quote(name)"
+      "||' SELECT*FROM\"%w\".'||quote(name)"
+      "FROM %s.sqlite_schema "
+      "WHERE type='table'AND coalesce(rootpage,1)>0",
+      zDbVacuum, zDbMain, zDbVacuum
+  );
+  assert( (db->mDbFlags & DBFLAG_Vacuum)!=0 );
+  db->mDbFlags &= ~DBFLAG_Vacuum;
+  if( rc!=SQLITE_OK ) goto end_of_vacuum;
+
+  /* Copy the triggers, views, and virtual tables from the main database
+  ** over to the temporary database.  None of these objects has any
+  ** associated storage, so all we have to do is copy their entries
+  ** from the schema table.
+  */
+  rc = execSqlF(db, pzErrMsg,
+      "INSERT INTO %s.sqlite_schema"
+      " SELECT*FROM \"%w\".sqlite_schema"
+      " WHERE type IN('view','trigger')"
+      " OR(type='table'AND rootpage=0)",
+      zDbVacuum, zDbMain
+  );
+  if( rc ) goto end_of_vacuum;
+
+  /* At this point, there is a write transaction open on both the
+  ** vacuum database and the main database. Assuming no error occurs,
+  ** both transactions are closed by this block - the main database
+  ** transaction by sqlite3BtreeCopyFile() and the other by an explicit
+  ** call to sqlite3BtreeCommit().
+  */
+  {
+    u32 meta;
+    int i;
+
+    /* This array determines which meta meta values are preserved in the
+    ** vacuum.  Even entries are the meta value number and odd entries
+    ** are an increment to apply to the meta value after the vacuum.
+    ** The increment is used to increase the schema cookie so that other
+    ** connections to the same database will know to reread the schema.
+    */
+    static const unsigned char aCopy[] = {
+       BTREE_SCHEMA_VERSION,     1,  /* Add one to the old schema cookie */
+       BTREE_DEFAULT_CACHE_SIZE, 0,  /* Preserve the default page cache size */
+       BTREE_TEXT_ENCODING,      0,  /* Preserve the text encoding */
+       BTREE_USER_VERSION,       0,  /* Preserve the user version */
+       BTREE_APPLICATION_ID,     0,  /* Preserve the application id */
+    };
+
+    assert( SQLITE_TXN_WRITE==sqlite3BtreeTxnState(pTemp) );
+    assert( pOut!=0 || SQLITE_TXN_WRITE==sqlite3BtreeTxnState(pMain) );
+
+    /* Copy Btree meta values */
+    for(i=0; i<ArraySize(aCopy); i+=2){
+      /* GetMeta() and UpdateMeta() cannot fail in this context because
+      ** we already have page 1 loaded into cache and marked dirty. */
+      sqlite3BtreeGetMeta(pMain, aCopy[i], &meta);
+      rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta+aCopy[i+1]);
+      if( NEVER(rc!=SQLITE_OK) ) goto end_of_vacuum;
+    }
+
+    if( pOut==0 ){
+      rc = sqlite3BtreeCopyFile(pMain, pTemp);
+    }
+    if( rc!=SQLITE_OK ) goto end_of_vacuum;
+    rc = sqlite3BtreeCommit(pTemp);
+    if( rc!=SQLITE_OK ) goto end_of_vacuum;
+#ifndef SQLITE_OMIT_AUTOVACUUM
+    if( pOut==0 ){
+      sqlite3BtreeSetAutoVacuum(pMain, sqlite3BtreeGetAutoVacuum(pTemp));
+    }
+#endif
+  }
+
+  assert( rc==SQLITE_OK );
+  if( pOut==0 ){
+    nRes = sqlite3BtreeGetRequestedReserve(pTemp);
+    rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes,1);
+  }
+
+end_of_vacuum:
+  /* Restore the original value of db->flags */
+  db->init.iDb = 0;
+  db->mDbFlags = saved_mDbFlags;
+  db->flags = saved_flags;
+  db->nChange = saved_nChange;
+  db->nTotalChange = saved_nTotalChange;
+  db->mTrace = saved_mTrace;
+  sqlite3BtreeSetPageSize(pMain, -1, 0, 1);
+
+  /* Currently there is an SQL level transaction open on the vacuum
+  ** database. No locks are held on any other files (since the main file
+  ** was committed at the btree level). So it safe to end the transaction
+  ** by manually setting the autoCommit flag to true and detaching the
+  ** vacuum database. The vacuum_db journal file is deleted when the pager
+  ** is closed by the DETACH.
+  */
+  db->autoCommit = 1;
+
+  if( pDb ){
+    sqlite3BtreeClose(pDb->pBt);
+    pDb->pBt = 0;
+    pDb->pSchema = 0;
+  }
+
+  /* This both clears the schemas and reduces the size of the db->aDb[]
+  ** array. */
+  sqlite3ResetAllSchemasOfConnection(db);
+
+  return rc;
+}
+
+#endif  /* SQLITE_OMIT_VACUUM && SQLITE_OMIT_ATTACH */
+
+/************** End of vacuum.c **********************************************/
+/************** Begin file vtab.c ********************************************/
+/*
+** 2006 June 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used to help implement virtual tables.
+*/
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/* #include "sqliteInt.h" */
+
+/*
+** Before a virtual table xCreate() or xConnect() method is invoked, the
+** sqlite3.pVtabCtx member variable is set to point to an instance of
+** this struct allocated on the stack. It is used by the implementation of
+** the sqlite3_declare_vtab() and sqlite3_vtab_config() APIs, both of which
+** are invoked only from within xCreate and xConnect methods.
+*/
+struct VtabCtx {
+  VTable *pVTable;    /* The virtual table being constructed */
+  Table *pTab;        /* The Table object to which the virtual table belongs */
+  VtabCtx *pPrior;    /* Parent context (if any) */
+  int bDeclared;      /* True after sqlite3_declare_vtab() is called */
+};
+
+/*
+** Construct and install a Module object for a virtual table.  When this
+** routine is called, it is guaranteed that all appropriate locks are held
+** and the module is not already part of the connection.
+**
+** If there already exists a module with zName, replace it with the new one.
+** If pModule==0, then delete the module zName if it exists.
+*/
+SQLITE_PRIVATE Module *sqlite3VtabCreateModule(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux,                     /* Context pointer for xCreate/xConnect */
+  void (*xDestroy)(void *)        /* Module destructor function */
+){
+  Module *pMod;
+  Module *pDel;
+  char *zCopy;
+  if( pModule==0 ){
+    zCopy = (char*)zName;
+    pMod = 0;
+  }else{
+    int nName = sqlite3Strlen30(zName);
+    pMod = (Module *)sqlite3Malloc(sizeof(Module) + nName + 1);
+    if( pMod==0 ){
+      sqlite3OomFault(db);
+      return 0;
+    }
+    zCopy = (char *)(&pMod[1]);
+    memcpy(zCopy, zName, nName+1);
+    pMod->zName = zCopy;
+    pMod->pModule = pModule;
+    pMod->pAux = pAux;
+    pMod->xDestroy = xDestroy;
+    pMod->pEpoTab = 0;
+    pMod->nRefModule = 1;
+  }
+  pDel = (Module *)sqlite3HashInsert(&db->aModule,zCopy,(void*)pMod);
+  if( pDel ){
+    if( pDel==pMod ){
+      sqlite3OomFault(db);
+      sqlite3DbFree(db, pDel);
+      pMod = 0;
+    }else{
+      sqlite3VtabEponymousTableClear(db, pDel);
+      sqlite3VtabModuleUnref(db, pDel);
+    }
+  }
+  return pMod;
+}
+
+/*
+** The actual function that does the work of creating a new module.
+** This function implements the sqlite3_create_module() and
+** sqlite3_create_module_v2() interfaces.
+*/
+static int createModule(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux,                     /* Context pointer for xCreate/xConnect */
+  void (*xDestroy)(void *)        /* Module destructor function */
+){
+  int rc = SQLITE_OK;
+
+  sqlite3_mutex_enter(db->mutex);
+  (void)sqlite3VtabCreateModule(db, zName, pModule, pAux, xDestroy);
+  rc = sqlite3ApiExit(db, rc);
+  if( rc!=SQLITE_OK && xDestroy ) xDestroy(pAux);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+
+/*
+** External API function used to create a new virtual-table module.
+*/
+SQLITE_API int sqlite3_create_module(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux                      /* Context pointer for xCreate/xConnect */
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  return createModule(db, zName, pModule, pAux, 0);
+}
+
+/*
+** External API function used to create a new virtual-table module.
+*/
+SQLITE_API int sqlite3_create_module_v2(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux,                     /* Context pointer for xCreate/xConnect */
+  void (*xDestroy)(void *)        /* Module destructor function */
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  return createModule(db, zName, pModule, pAux, xDestroy);
+}
+
+/*
+** External API to drop all virtual-table modules, except those named
+** on the azNames list.
+*/
+SQLITE_API int sqlite3_drop_modules(sqlite3 *db, const char** azNames){
+  HashElem *pThis, *pNext;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  for(pThis=sqliteHashFirst(&db->aModule); pThis; pThis=pNext){
+    Module *pMod = (Module*)sqliteHashData(pThis);
+    pNext = sqliteHashNext(pThis);
+    if( azNames ){
+      int ii;
+      for(ii=0; azNames[ii]!=0 && strcmp(azNames[ii],pMod->zName)!=0; ii++){}
+      if( azNames[ii]!=0 ) continue;
+    }
+    createModule(db, pMod->zName, 0, 0, 0);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Decrement the reference count on a Module object.  Destroy the
+** module when the reference count reaches zero.
+*/
+SQLITE_PRIVATE void sqlite3VtabModuleUnref(sqlite3 *db, Module *pMod){
+  assert( pMod->nRefModule>0 );
+  pMod->nRefModule--;
+  if( pMod->nRefModule==0 ){
+    if( pMod->xDestroy ){
+      pMod->xDestroy(pMod->pAux);
+    }
+    assert( pMod->pEpoTab==0 );
+    sqlite3DbFree(db, pMod);
+  }
+}
+
+/*
+** Lock the virtual table so that it cannot be disconnected.
+** Locks nest.  Every lock should have a corresponding unlock.
+** If an unlock is omitted, resources leaks will occur.
+**
+** If a disconnect is attempted while a virtual table is locked,
+** the disconnect is deferred until all locks have been removed.
+*/
+SQLITE_PRIVATE void sqlite3VtabLock(VTable *pVTab){
+  pVTab->nRef++;
+}
+
+
+/*
+** pTab is a pointer to a Table structure representing a virtual-table.
+** Return a pointer to the VTable object used by connection db to access
+** this virtual-table, if one has been created, or NULL otherwise.
+*/
+SQLITE_PRIVATE VTable *sqlite3GetVTable(sqlite3 *db, Table *pTab){
+  VTable *pVtab;
+  assert( IsVirtual(pTab) );
+  for(pVtab=pTab->u.vtab.p; pVtab && pVtab->db!=db; pVtab=pVtab->pNext);
+  return pVtab;
+}
+
+/*
+** Decrement the ref-count on a virtual table object. When the ref-count
+** reaches zero, call the xDisconnect() method to delete the object.
+*/
+SQLITE_PRIVATE void sqlite3VtabUnlock(VTable *pVTab){
+  sqlite3 *db = pVTab->db;
+
+  assert( db );
+  assert( pVTab->nRef>0 );
+  assert( db->eOpenState==SQLITE_STATE_OPEN
+       || db->eOpenState==SQLITE_STATE_ZOMBIE );
+
+  pVTab->nRef--;
+  if( pVTab->nRef==0 ){
+    sqlite3_vtab *p = pVTab->pVtab;
+    if( p ){
+      p->pModule->xDisconnect(p);
+    }
+    sqlite3VtabModuleUnref(pVTab->db, pVTab->pMod);
+    sqlite3DbFree(db, pVTab);
+  }
+}
+
+/*
+** Table p is a virtual table. This function moves all elements in the
+** p->u.vtab.p list to the sqlite3.pDisconnect lists of their associated
+** database connections to be disconnected at the next opportunity.
+** Except, if argument db is not NULL, then the entry associated with
+** connection db is left in the p->u.vtab.p list.
+*/
+static VTable *vtabDisconnectAll(sqlite3 *db, Table *p){
+  VTable *pRet = 0;
+  VTable *pVTable;
+
+  assert( IsVirtual(p) );
+  pVTable = p->u.vtab.p;
+  p->u.vtab.p = 0;
+
+  /* Assert that the mutex (if any) associated with the BtShared database
+  ** that contains table p is held by the caller. See header comments
+  ** above function sqlite3VtabUnlockList() for an explanation of why
+  ** this makes it safe to access the sqlite3.pDisconnect list of any
+  ** database connection that may have an entry in the p->u.vtab.p list.
+  */
+  assert( db==0 || sqlite3SchemaMutexHeld(db, 0, p->pSchema) );
+
+  while( pVTable ){
+    sqlite3 *db2 = pVTable->db;
+    VTable *pNext = pVTable->pNext;
+    assert( db2 );
+    if( db2==db ){
+      pRet = pVTable;
+      p->u.vtab.p = pRet;
+      pRet->pNext = 0;
+    }else{
+      pVTable->pNext = db2->pDisconnect;
+      db2->pDisconnect = pVTable;
+    }
+    pVTable = pNext;
+  }
+
+  assert( !db || pRet );
+  return pRet;
+}
+
+/*
+** Table *p is a virtual table. This function removes the VTable object
+** for table *p associated with database connection db from the linked
+** list in p->pVTab. It also decrements the VTable ref count. This is
+** used when closing database connection db to free all of its VTable
+** objects without disturbing the rest of the Schema object (which may
+** be being used by other shared-cache connections).
+*/
+SQLITE_PRIVATE void sqlite3VtabDisconnect(sqlite3 *db, Table *p){
+  VTable **ppVTab;
+
+  assert( IsVirtual(p) );
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  for(ppVTab=&p->u.vtab.p; *ppVTab; ppVTab=&(*ppVTab)->pNext){
+    if( (*ppVTab)->db==db  ){
+      VTable *pVTab = *ppVTab;
+      *ppVTab = pVTab->pNext;
+      sqlite3VtabUnlock(pVTab);
+      break;
+    }
+  }
+}
+
+
+/*
+** Disconnect all the virtual table objects in the sqlite3.pDisconnect list.
+**
+** This function may only be called when the mutexes associated with all
+** shared b-tree databases opened using connection db are held by the
+** caller. This is done to protect the sqlite3.pDisconnect list. The
+** sqlite3.pDisconnect list is accessed only as follows:
+**
+**   1) By this function. In this case, all BtShared mutexes and the mutex
+**      associated with the database handle itself must be held.
+**
+**   2) By function vtabDisconnectAll(), when it adds a VTable entry to
+**      the sqlite3.pDisconnect list. In this case either the BtShared mutex
+**      associated with the database the virtual table is stored in is held
+**      or, if the virtual table is stored in a non-sharable database, then
+**      the database handle mutex is held.
+**
+** As a result, a sqlite3.pDisconnect cannot be accessed simultaneously
+** by multiple threads. It is thread-safe.
+*/
+SQLITE_PRIVATE void sqlite3VtabUnlockList(sqlite3 *db){
+  VTable *p = db->pDisconnect;
+
+  assert( sqlite3BtreeHoldsAllMutexes(db) );
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  if( p ){
+    db->pDisconnect = 0;
+    do {
+      VTable *pNext = p->pNext;
+      sqlite3VtabUnlock(p);
+      p = pNext;
+    }while( p );
+  }
+}
+
+/*
+** Clear any and all virtual-table information from the Table record.
+** This routine is called, for example, just before deleting the Table
+** record.
+**
+** Since it is a virtual-table, the Table structure contains a pointer
+** to the head of a linked list of VTable structures. Each VTable
+** structure is associated with a single sqlite3* user of the schema.
+** The reference count of the VTable structure associated with database
+** connection db is decremented immediately (which may lead to the
+** structure being xDisconnected and free). Any other VTable structures
+** in the list are moved to the sqlite3.pDisconnect list of the associated
+** database connection.
+*/
+SQLITE_PRIVATE void sqlite3VtabClear(sqlite3 *db, Table *p){
+  assert( IsVirtual(p) );
+  assert( db!=0 );
+  if( db->pnBytesFreed==0 ) vtabDisconnectAll(0, p);
+  if( p->u.vtab.azArg ){
+    int i;
+    for(i=0; i<p->u.vtab.nArg; i++){
+      if( i!=1 ) sqlite3DbFree(db, p->u.vtab.azArg[i]);
+    }
+    sqlite3DbFree(db, p->u.vtab.azArg);
+  }
+}
+
+/*
+** Add a new module argument to pTable->u.vtab.azArg[].
+** The string is not copied - the pointer is stored.  The
+** string will be freed automatically when the table is
+** deleted.
+*/
+static void addModuleArgument(Parse *pParse, Table *pTable, char *zArg){
+  sqlite3_int64 nBytes;
+  char **azModuleArg;
+  sqlite3 *db = pParse->db;
+
+  assert( IsVirtual(pTable) );
+  nBytes = sizeof(char *)*(2+pTable->u.vtab.nArg);
+  if( pTable->u.vtab.nArg+3>=db->aLimit[SQLITE_LIMIT_COLUMN] ){
+    sqlite3ErrorMsg(pParse, "too many columns on %s", pTable->zName);
+  }
+  azModuleArg = sqlite3DbRealloc(db, pTable->u.vtab.azArg, nBytes);
+  if( azModuleArg==0 ){
+    sqlite3DbFree(db, zArg);
+  }else{
+    int i = pTable->u.vtab.nArg++;
+    azModuleArg[i] = zArg;
+    azModuleArg[i+1] = 0;
+    pTable->u.vtab.azArg = azModuleArg;
+  }
+}
+
+/*
+** The parser calls this routine when it first sees a CREATE VIRTUAL TABLE
+** statement.  The module name has been parsed, but the optional list
+** of parameters that follow the module name are still pending.
+*/
+SQLITE_PRIVATE void sqlite3VtabBeginParse(
+  Parse *pParse,        /* Parsing context */
+  Token *pName1,        /* Name of new table, or database name */
+  Token *pName2,        /* Name of new table or NULL */
+  Token *pModuleName,   /* Name of the module for the virtual table */
+  int ifNotExists       /* No error if the table already exists */
+){
+  Table *pTable;        /* The new virtual table */
+  sqlite3 *db;          /* Database connection */
+
+  sqlite3StartTable(pParse, pName1, pName2, 0, 0, 1, ifNotExists);
+  pTable = pParse->pNewTable;
+  if( pTable==0 ) return;
+  assert( 0==pTable->pIndex );
+  pTable->eTabType = TABTYP_VTAB;
+
+  db = pParse->db;
+
+  assert( pTable->u.vtab.nArg==0 );
+  addModuleArgument(pParse, pTable, sqlite3NameFromToken(db, pModuleName));
+  addModuleArgument(pParse, pTable, 0);
+  addModuleArgument(pParse, pTable, sqlite3DbStrDup(db, pTable->zName));
+  assert( (pParse->sNameToken.z==pName2->z && pName2->z!=0)
+       || (pParse->sNameToken.z==pName1->z && pName2->z==0)
+  );
+  pParse->sNameToken.n = (int)(
+      &pModuleName->z[pModuleName->n] - pParse->sNameToken.z
+  );
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Creating a virtual table invokes the authorization callback twice.
+  ** The first invocation, to obtain permission to INSERT a row into the
+  ** sqlite_schema table, has already been made by sqlite3StartTable().
+  ** The second call, to obtain permission to create the table, is made now.
+  */
+  if( pTable->u.vtab.azArg ){
+    int iDb = sqlite3SchemaToIndex(db, pTable->pSchema);
+    assert( iDb>=0 ); /* The database the table is being created in */
+    sqlite3AuthCheck(pParse, SQLITE_CREATE_VTABLE, pTable->zName,
+            pTable->u.vtab.azArg[0], pParse->db->aDb[iDb].zDbSName);
+  }
+#endif
+}
+
+/*
+** This routine takes the module argument that has been accumulating
+** in pParse->zArg[] and appends it to the list of arguments on the
+** virtual table currently under construction in pParse->pTable.
+*/
+static void addArgumentToVtab(Parse *pParse){
+  if( pParse->sArg.z && pParse->pNewTable ){
+    const char *z = (const char*)pParse->sArg.z;
+    int n = pParse->sArg.n;
+    sqlite3 *db = pParse->db;
+    addModuleArgument(pParse, pParse->pNewTable, sqlite3DbStrNDup(db, z, n));
+  }
+}
+
+/*
+** The parser calls this routine after the CREATE VIRTUAL TABLE statement
+** has been completely parsed.
+*/
+SQLITE_PRIVATE void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){
+  Table *pTab = pParse->pNewTable;  /* The table being constructed */
+  sqlite3 *db = pParse->db;         /* The database connection */
+
+  if( pTab==0 ) return;
+  assert( IsVirtual(pTab) );
+  addArgumentToVtab(pParse);
+  pParse->sArg.z = 0;
+  if( pTab->u.vtab.nArg<1 ) return;
+
+  /* If the CREATE VIRTUAL TABLE statement is being entered for the
+  ** first time (in other words if the virtual table is actually being
+  ** created now instead of just being read out of sqlite_schema) then
+  ** do additional initialization work and store the statement text
+  ** in the sqlite_schema table.
+  */
+  if( !db->init.busy ){
+    char *zStmt;
+    char *zWhere;
+    int iDb;
+    int iReg;
+    Vdbe *v;
+
+    sqlite3MayAbort(pParse);
+
+    /* Compute the complete text of the CREATE VIRTUAL TABLE statement */
+    if( pEnd ){
+      pParse->sNameToken.n = (int)(pEnd->z - pParse->sNameToken.z) + pEnd->n;
+    }
+    zStmt = sqlite3MPrintf(db, "CREATE VIRTUAL TABLE %T", &pParse->sNameToken);
+
+    /* A slot for the record has already been allocated in the
+    ** schema table.  We just need to update that slot with all
+    ** the information we've collected.
+    **
+    ** The VM register number pParse->regRowid holds the rowid of an
+    ** entry in the sqlite_schema table that was created for this vtab
+    ** by sqlite3StartTable().
+    */
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    sqlite3NestedParse(pParse,
+      "UPDATE %Q." LEGACY_SCHEMA_TABLE " "
+         "SET type='table', name=%Q, tbl_name=%Q, rootpage=0, sql=%Q "
+       "WHERE rowid=#%d",
+      db->aDb[iDb].zDbSName,
+      pTab->zName,
+      pTab->zName,
+      zStmt,
+      pParse->regRowid
+    );
+    v = sqlite3GetVdbe(pParse);
+    sqlite3ChangeCookie(pParse, iDb);
+
+    sqlite3VdbeAddOp0(v, OP_Expire);
+    zWhere = sqlite3MPrintf(db, "name=%Q AND sql=%Q", pTab->zName, zStmt);
+    sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere, 0);
+    sqlite3DbFree(db, zStmt);
+
+    iReg = ++pParse->nMem;
+    sqlite3VdbeLoadString(v, iReg, pTab->zName);
+    sqlite3VdbeAddOp2(v, OP_VCreate, iDb, iReg);
+  }else{
+    /* If we are rereading the sqlite_schema table create the in-memory
+    ** record of the table. */
+    Table *pOld;
+    Schema *pSchema = pTab->pSchema;
+    const char *zName = pTab->zName;
+    assert( zName!=0 );
+    sqlite3MarkAllShadowTablesOf(db, pTab);
+    pOld = sqlite3HashInsert(&pSchema->tblHash, zName, pTab);
+    if( pOld ){
+      sqlite3OomFault(db);
+      assert( pTab==pOld );  /* Malloc must have failed inside HashInsert() */
+      return;
+    }
+    pParse->pNewTable = 0;
+  }
+}
+
+/*
+** The parser calls this routine when it sees the first token
+** of an argument to the module name in a CREATE VIRTUAL TABLE statement.
+*/
+SQLITE_PRIVATE void sqlite3VtabArgInit(Parse *pParse){
+  addArgumentToVtab(pParse);
+  pParse->sArg.z = 0;
+  pParse->sArg.n = 0;
+}
+
+/*
+** The parser calls this routine for each token after the first token
+** in an argument to the module name in a CREATE VIRTUAL TABLE statement.
+*/
+SQLITE_PRIVATE void sqlite3VtabArgExtend(Parse *pParse, Token *p){
+  Token *pArg = &pParse->sArg;
+  if( pArg->z==0 ){
+    pArg->z = p->z;
+    pArg->n = p->n;
+  }else{
+    assert(pArg->z <= p->z);
+    pArg->n = (int)(&p->z[p->n] - pArg->z);
+  }
+}
+
+/*
+** Invoke a virtual table constructor (either xCreate or xConnect). The
+** pointer to the function to invoke is passed as the fourth parameter
+** to this procedure.
+*/
+static int vtabCallConstructor(
+  sqlite3 *db,
+  Table *pTab,
+  Module *pMod,
+  int (*xConstruct)(sqlite3*,void*,int,const char*const*,sqlite3_vtab**,char**),
+  char **pzErr
+){
+  VtabCtx sCtx;
+  VTable *pVTable;
+  int rc;
+  const char *const*azArg;
+  int nArg = pTab->u.vtab.nArg;
+  char *zErr = 0;
+  char *zModuleName;
+  int iDb;
+  VtabCtx *pCtx;
+
+  assert( IsVirtual(pTab) );
+  azArg = (const char *const*)pTab->u.vtab.azArg;
+
+  /* Check that the virtual-table is not already being initialized */
+  for(pCtx=db->pVtabCtx; pCtx; pCtx=pCtx->pPrior){
+    if( pCtx->pTab==pTab ){
+      *pzErr = sqlite3MPrintf(db,
+          "vtable constructor called recursively: %s", pTab->zName
+      );
+      return SQLITE_LOCKED;
+    }
+  }
+
+  zModuleName = sqlite3DbStrDup(db, pTab->zName);
+  if( !zModuleName ){
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  pVTable = sqlite3MallocZero(sizeof(VTable));
+  if( !pVTable ){
+    sqlite3OomFault(db);
+    sqlite3DbFree(db, zModuleName);
+    return SQLITE_NOMEM_BKPT;
+  }
+  pVTable->db = db;
+  pVTable->pMod = pMod;
+  pVTable->eVtabRisk = SQLITE_VTABRISK_Normal;
+
+  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+  pTab->u.vtab.azArg[1] = db->aDb[iDb].zDbSName;
+
+  /* Invoke the virtual table constructor */
+  assert( &db->pVtabCtx );
+  assert( xConstruct );
+  sCtx.pTab = pTab;
+  sCtx.pVTable = pVTable;
+  sCtx.pPrior = db->pVtabCtx;
+  sCtx.bDeclared = 0;
+  db->pVtabCtx = &sCtx;
+  pTab->nTabRef++;
+  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pVTable->pVtab, &zErr);
+  assert( pTab!=0 );
+  assert( pTab->nTabRef>1 || rc!=SQLITE_OK );
+  sqlite3DeleteTable(db, pTab);
+  db->pVtabCtx = sCtx.pPrior;
+  if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
+  assert( sCtx.pTab==pTab );
+
+  if( SQLITE_OK!=rc ){
+    if( zErr==0 ){
+      *pzErr = sqlite3MPrintf(db, "vtable constructor failed: %s", zModuleName);
+    }else {
+      *pzErr = sqlite3MPrintf(db, "%s", zErr);
+      sqlite3_free(zErr);
+    }
+    sqlite3DbFree(db, pVTable);
+  }else if( ALWAYS(pVTable->pVtab) ){
+    /* Justification of ALWAYS():  A correct vtab constructor must allocate
+    ** the sqlite3_vtab object if successful.  */
+    memset(pVTable->pVtab, 0, sizeof(pVTable->pVtab[0]));
+    pVTable->pVtab->pModule = pMod->pModule;
+    pMod->nRefModule++;
+    pVTable->nRef = 1;
+    if( sCtx.bDeclared==0 ){
+      const char *zFormat = "vtable constructor did not declare schema: %s";
+      *pzErr = sqlite3MPrintf(db, zFormat, zModuleName);
+      sqlite3VtabUnlock(pVTable);
+      rc = SQLITE_ERROR;
+    }else{
+      int iCol;
+      u16 oooHidden = 0;
+      /* If everything went according to plan, link the new VTable structure
+      ** into the linked list headed by pTab->u.vtab.p. Then loop through the
+      ** columns of the table to see if any of them contain the token "hidden".
+      ** If so, set the Column COLFLAG_HIDDEN flag and remove the token from
+      ** the type string.  */
+      pVTable->pNext = pTab->u.vtab.p;
+      pTab->u.vtab.p = pVTable;
+
+      for(iCol=0; iCol<pTab->nCol; iCol++){
+        char *zType = sqlite3ColumnType(&pTab->aCol[iCol], "");
+        int nType;
+        int i = 0;
+        nType = sqlite3Strlen30(zType);
+        for(i=0; i<nType; i++){
+          if( 0==sqlite3StrNICmp("hidden", &zType[i], 6)
+           && (i==0 || zType[i-1]==' ')
+           && (zType[i+6]=='\0' || zType[i+6]==' ')
+          ){
+            break;
+          }
+        }
+        if( i<nType ){
+          int j;
+          int nDel = 6 + (zType[i+6] ? 1 : 0);
+          for(j=i; (j+nDel)<=nType; j++){
+            zType[j] = zType[j+nDel];
+          }
+          if( zType[i]=='\0' && i>0 ){
+            assert(zType[i-1]==' ');
+            zType[i-1] = '\0';
+          }
+          pTab->aCol[iCol].colFlags |= COLFLAG_HIDDEN;
+          pTab->tabFlags |= TF_HasHidden;
+          oooHidden = TF_OOOHidden;
+        }else{
+          pTab->tabFlags |= oooHidden;
+        }
+      }
+    }
+  }
+
+  sqlite3DbFree(db, zModuleName);
+  return rc;
+}
+
+/*
+** This function is invoked by the parser to call the xConnect() method
+** of the virtual table pTab. If an error occurs, an error code is returned
+** and an error left in pParse.
+**
+** This call is a no-op if table pTab is not a virtual table.
+*/
+SQLITE_PRIVATE int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
+  sqlite3 *db = pParse->db;
+  const char *zMod;
+  Module *pMod;
+  int rc;
+
+  assert( pTab );
+  assert( IsVirtual(pTab) );
+  if( sqlite3GetVTable(db, pTab) ){
+    return SQLITE_OK;
+  }
+
+  /* Locate the required virtual table module */
+  zMod = pTab->u.vtab.azArg[0];
+  pMod = (Module*)sqlite3HashFind(&db->aModule, zMod);
+
+  if( !pMod ){
+    const char *zModule = pTab->u.vtab.azArg[0];
+    sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
+    rc = SQLITE_ERROR;
+  }else{
+    char *zErr = 0;
+    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xConnect, &zErr);
+    if( rc!=SQLITE_OK ){
+      sqlite3ErrorMsg(pParse, "%s", zErr);
+      pParse->rc = rc;
+    }
+    sqlite3DbFree(db, zErr);
+  }
+
+  return rc;
+}
+/*
+** Grow the db->aVTrans[] array so that there is room for at least one
+** more v-table. Return SQLITE_NOMEM if a malloc fails, or SQLITE_OK otherwise.
+*/
+static int growVTrans(sqlite3 *db){
+  const int ARRAY_INCR = 5;
+
+  /* Grow the sqlite3.aVTrans array if required */
+  if( (db->nVTrans%ARRAY_INCR)==0 ){
+    VTable **aVTrans;
+    sqlite3_int64 nBytes = sizeof(sqlite3_vtab*)*
+                                 ((sqlite3_int64)db->nVTrans + ARRAY_INCR);
+    aVTrans = sqlite3DbRealloc(db, (void *)db->aVTrans, nBytes);
+    if( !aVTrans ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    memset(&aVTrans[db->nVTrans], 0, sizeof(sqlite3_vtab *)*ARRAY_INCR);
+    db->aVTrans = aVTrans;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Add the virtual table pVTab to the array sqlite3.aVTrans[]. Space should
+** have already been reserved using growVTrans().
+*/
+static void addToVTrans(sqlite3 *db, VTable *pVTab){
+  /* Add pVtab to the end of sqlite3.aVTrans */
+  db->aVTrans[db->nVTrans++] = pVTab;
+  sqlite3VtabLock(pVTab);
+}
+
+/*
+** This function is invoked by the vdbe to call the xCreate method
+** of the virtual table named zTab in database iDb.
+**
+** If an error occurs, *pzErr is set to point to an English language
+** description of the error and an SQLITE_XXX error code is returned.
+** In this case the caller must call sqlite3DbFree(db, ) on *pzErr.
+*/
+SQLITE_PRIVATE int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab, char **pzErr){
+  int rc = SQLITE_OK;
+  Table *pTab;
+  Module *pMod;
+  const char *zMod;
+
+  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zDbSName);
+  assert( pTab && IsVirtual(pTab) && !pTab->u.vtab.p );
+
+  /* Locate the required virtual table module */
+  zMod = pTab->u.vtab.azArg[0];
+  pMod = (Module*)sqlite3HashFind(&db->aModule, zMod);
+
+  /* If the module has been registered and includes a Create method,
+  ** invoke it now. If the module has not been registered, return an
+  ** error. Otherwise, do nothing.
+  */
+  if( pMod==0 || pMod->pModule->xCreate==0 || pMod->pModule->xDestroy==0 ){
+    *pzErr = sqlite3MPrintf(db, "no such module: %s", zMod);
+    rc = SQLITE_ERROR;
+  }else{
+    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
+  }
+
+  /* Justification of ALWAYS():  The xConstructor method is required to
+  ** create a valid sqlite3_vtab if it returns SQLITE_OK. */
+  if( rc==SQLITE_OK && ALWAYS(sqlite3GetVTable(db, pTab)) ){
+    rc = growVTrans(db);
+    if( rc==SQLITE_OK ){
+      addToVTrans(db, sqlite3GetVTable(db, pTab));
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is used to set the schema of a virtual table.  It is only
+** valid to call this function from within the xCreate() or xConnect() of a
+** virtual table module.
+*/
+SQLITE_API int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){
+  VtabCtx *pCtx;
+  int rc = SQLITE_OK;
+  Table *pTab;
+  Parse sParse;
+  int initBusy;
+  int i;
+  const unsigned char *z;
+  static const u8 aKeyword[] = { TK_CREATE, TK_TABLE, 0 };
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zCreateTable==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+
+  /* Verify that the first two keywords in the CREATE TABLE statement
+  ** really are "CREATE" and "TABLE".  If this is not the case, then
+  ** sqlite3_declare_vtab() is being misused.
+  */
+  z = (const unsigned char*)zCreateTable;
+  for(i=0; aKeyword[i]; i++){
+    int tokenType = 0;
+    do{
+      z += sqlite3GetToken(z, &tokenType);
+    }while( tokenType==TK_SPACE || tokenType==TK_COMMENT );
+    if( tokenType!=aKeyword[i] ){
+      sqlite3ErrorWithMsg(db, SQLITE_ERROR, "syntax error");
+      return SQLITE_ERROR;
+    }
+  }
+
+  sqlite3_mutex_enter(db->mutex);
+  pCtx = db->pVtabCtx;
+  if( !pCtx || pCtx->bDeclared ){
+    sqlite3Error(db, SQLITE_MISUSE_BKPT);
+    sqlite3_mutex_leave(db->mutex);
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  pTab = pCtx->pTab;
+  assert( IsVirtual(pTab) );
+
+  sqlite3ParseObjectInit(&sParse, db);
+  sParse.eParseMode = PARSE_MODE_DECLARE_VTAB;
+  sParse.disableTriggers = 1;
+  /* We should never be able to reach this point while loading the
+  ** schema.  Nevertheless, defend against that (turn off db->init.busy)
+  ** in case a bug arises. */
+  assert( db->init.busy==0 );
+  initBusy = db->init.busy;
+  db->init.busy = 0;
+  sParse.nQueryLoop = 1;
+  if( SQLITE_OK==sqlite3RunParser(&sParse, zCreateTable) ){
+    assert( sParse.pNewTable!=0 );
+    assert( !db->mallocFailed );
+    assert( IsOrdinaryTable(sParse.pNewTable) );
+    assert( sParse.zErrMsg==0 );
+    if( !pTab->aCol ){
+      Table *pNew = sParse.pNewTable;
+      Index *pIdx;
+      pTab->aCol = pNew->aCol;
+      assert( IsOrdinaryTable(pNew) );
+      sqlite3ExprListDelete(db, pNew->u.tab.pDfltList);
+      pTab->nNVCol = pTab->nCol = pNew->nCol;
+      pTab->tabFlags |= pNew->tabFlags & (TF_WithoutRowid|TF_NoVisibleRowid);
+      pNew->nCol = 0;
+      pNew->aCol = 0;
+      assert( pTab->pIndex==0 );
+      assert( HasRowid(pNew) || sqlite3PrimaryKeyIndex(pNew)!=0 );
+      if( !HasRowid(pNew)
+       && pCtx->pVTable->pMod->pModule->xUpdate!=0
+       && sqlite3PrimaryKeyIndex(pNew)->nKeyCol!=1
+      ){
+        /* WITHOUT ROWID virtual tables must either be read-only (xUpdate==0)
+        ** or else must have a single-column PRIMARY KEY */
+        rc = SQLITE_ERROR;
+      }
+      pIdx = pNew->pIndex;
+      if( pIdx ){
+        assert( pIdx->pNext==0 );
+        pTab->pIndex = pIdx;
+        pNew->pIndex = 0;
+        pIdx->pTable = pTab;
+      }
+    }
+    pCtx->bDeclared = 1;
+  }else{
+    sqlite3ErrorWithMsg(db, SQLITE_ERROR,
+          (sParse.zErrMsg ? "%s" : 0), sParse.zErrMsg);
+    sqlite3DbFree(db, sParse.zErrMsg);
+    rc = SQLITE_ERROR;
+  }
+  sParse.eParseMode = PARSE_MODE_NORMAL;
+
+  if( sParse.pVdbe ){
+    sqlite3VdbeFinalize(sParse.pVdbe);
+  }
+  sqlite3DeleteTable(db, sParse.pNewTable);
+  sqlite3ParseObjectReset(&sParse);
+  db->init.busy = initBusy;
+
+  assert( (rc&0xff)==rc );
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** This function is invoked by the vdbe to call the xDestroy method
+** of the virtual table named zTab in database iDb. This occurs
+** when a DROP TABLE is mentioned.
+**
+** This call is a no-op if zTab is not a virtual table.
+*/
+SQLITE_PRIVATE int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab){
+  int rc = SQLITE_OK;
+  Table *pTab;
+
+  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zDbSName);
+  if( ALWAYS(pTab!=0)
+   && ALWAYS(IsVirtual(pTab))
+   && ALWAYS(pTab->u.vtab.p!=0)
+  ){
+    VTable *p;
+    int (*xDestroy)(sqlite3_vtab *);
+    for(p=pTab->u.vtab.p; p; p=p->pNext){
+      assert( p->pVtab );
+      if( p->pVtab->nRef>0 ){
+        return SQLITE_LOCKED;
+      }
+    }
+    p = vtabDisconnectAll(db, pTab);
+    xDestroy = p->pMod->pModule->xDestroy;
+    if( xDestroy==0 ) xDestroy = p->pMod->pModule->xDisconnect;
+    assert( xDestroy!=0 );
+    pTab->nTabRef++;
+    rc = xDestroy(p->pVtab);
+    /* Remove the sqlite3_vtab* from the aVTrans[] array, if applicable */
+    if( rc==SQLITE_OK ){
+      assert( pTab->u.vtab.p==p && p->pNext==0 );
+      p->pVtab = 0;
+      pTab->u.vtab.p = 0;
+      sqlite3VtabUnlock(p);
+    }
+    sqlite3DeleteTable(db, pTab);
+  }
+
+  return rc;
+}
+
+/*
+** This function invokes either the xRollback or xCommit method
+** of each of the virtual tables in the sqlite3.aVTrans array. The method
+** called is identified by the second argument, "offset", which is
+** the offset of the method to call in the sqlite3_module structure.
+**
+** The array is cleared after invoking the callbacks.
+*/
+static void callFinaliser(sqlite3 *db, int offset){
+  int i;
+  if( db->aVTrans ){
+    VTable **aVTrans = db->aVTrans;
+    db->aVTrans = 0;
+    for(i=0; i<db->nVTrans; i++){
+      VTable *pVTab = aVTrans[i];
+      sqlite3_vtab *p = pVTab->pVtab;
+      if( p ){
+        int (*x)(sqlite3_vtab *);
+        x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset);
+        if( x ) x(p);
+      }
+      pVTab->iSavepoint = 0;
+      sqlite3VtabUnlock(pVTab);
+    }
+    sqlite3DbFree(db, aVTrans);
+    db->nVTrans = 0;
+  }
+}
+
+/*
+** Invoke the xSync method of all virtual tables in the sqlite3.aVTrans
+** array. Return the error code for the first error that occurs, or
+** SQLITE_OK if all xSync operations are successful.
+**
+** If an error message is available, leave it in p->zErrMsg.
+*/
+SQLITE_PRIVATE int sqlite3VtabSync(sqlite3 *db, Vdbe *p){
+  int i;
+  int rc = SQLITE_OK;
+  VTable **aVTrans = db->aVTrans;
+
+  db->aVTrans = 0;
+  for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){
+    int (*x)(sqlite3_vtab *);
+    sqlite3_vtab *pVtab = aVTrans[i]->pVtab;
+    if( pVtab && (x = pVtab->pModule->xSync)!=0 ){
+      rc = x(pVtab);
+      sqlite3VtabImportErrmsg(p, pVtab);
+    }
+  }
+  db->aVTrans = aVTrans;
+  return rc;
+}
+
+/*
+** Invoke the xRollback method of all virtual tables in the
+** sqlite3.aVTrans array. Then clear the array itself.
+*/
+SQLITE_PRIVATE int sqlite3VtabRollback(sqlite3 *db){
+  callFinaliser(db, offsetof(sqlite3_module,xRollback));
+  return SQLITE_OK;
+}
+
+/*
+** Invoke the xCommit method of all virtual tables in the
+** sqlite3.aVTrans array. Then clear the array itself.
+*/
+SQLITE_PRIVATE int sqlite3VtabCommit(sqlite3 *db){
+  callFinaliser(db, offsetof(sqlite3_module,xCommit));
+  return SQLITE_OK;
+}
+
+/*
+** If the virtual table pVtab supports the transaction interface
+** (xBegin/xRollback/xCommit and optionally xSync) and a transaction is
+** not currently open, invoke the xBegin method now.
+**
+** If the xBegin call is successful, place the sqlite3_vtab pointer
+** in the sqlite3.aVTrans array.
+*/
+SQLITE_PRIVATE int sqlite3VtabBegin(sqlite3 *db, VTable *pVTab){
+  int rc = SQLITE_OK;
+  const sqlite3_module *pModule;
+
+  /* Special case: If db->aVTrans is NULL and db->nVTrans is greater
+  ** than zero, then this function is being called from within a
+  ** virtual module xSync() callback. It is illegal to write to
+  ** virtual module tables in this case, so return SQLITE_LOCKED.
+  */
+  if( sqlite3VtabInSync(db) ){
+    return SQLITE_LOCKED;
+  }
+  if( !pVTab ){
+    return SQLITE_OK;
+  }
+  pModule = pVTab->pVtab->pModule;
+
+  if( pModule->xBegin ){
+    int i;
+
+    /* If pVtab is already in the aVTrans array, return early */
+    for(i=0; i<db->nVTrans; i++){
+      if( db->aVTrans[i]==pVTab ){
+        return SQLITE_OK;
+      }
+    }
+
+    /* Invoke the xBegin method. If successful, add the vtab to the
+    ** sqlite3.aVTrans[] array. */
+    rc = growVTrans(db);
+    if( rc==SQLITE_OK ){
+      rc = pModule->xBegin(pVTab->pVtab);
+      if( rc==SQLITE_OK ){
+        int iSvpt = db->nStatement + db->nSavepoint;
+        addToVTrans(db, pVTab);
+        if( iSvpt && pModule->xSavepoint ){
+          pVTab->iSavepoint = iSvpt;
+          rc = pModule->xSavepoint(pVTab->pVtab, iSvpt-1);
+        }
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Invoke either the xSavepoint, xRollbackTo or xRelease method of all
+** virtual tables that currently have an open transaction. Pass iSavepoint
+** as the second argument to the virtual table method invoked.
+**
+** If op is SAVEPOINT_BEGIN, the xSavepoint method is invoked. If it is
+** SAVEPOINT_ROLLBACK, the xRollbackTo method. Otherwise, if op is
+** SAVEPOINT_RELEASE, then the xRelease method of each virtual table with
+** an open transaction is invoked.
+**
+** If any virtual table method returns an error code other than SQLITE_OK,
+** processing is abandoned and the error returned to the caller of this
+** function immediately. If all calls to virtual table methods are successful,
+** SQLITE_OK is returned.
+*/
+SQLITE_PRIVATE int sqlite3VtabSavepoint(sqlite3 *db, int op, int iSavepoint){
+  int rc = SQLITE_OK;
+
+  assert( op==SAVEPOINT_RELEASE||op==SAVEPOINT_ROLLBACK||op==SAVEPOINT_BEGIN );
+  assert( iSavepoint>=-1 );
+  if( db->aVTrans ){
+    int i;
+    for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){
+      VTable *pVTab = db->aVTrans[i];
+      const sqlite3_module *pMod = pVTab->pMod->pModule;
+      if( pVTab->pVtab && pMod->iVersion>=2 ){
+        int (*xMethod)(sqlite3_vtab *, int);
+        sqlite3VtabLock(pVTab);
+        switch( op ){
+          case SAVEPOINT_BEGIN:
+            xMethod = pMod->xSavepoint;
+            pVTab->iSavepoint = iSavepoint+1;
+            break;
+          case SAVEPOINT_ROLLBACK:
+            xMethod = pMod->xRollbackTo;
+            break;
+          default:
+            xMethod = pMod->xRelease;
+            break;
+        }
+        if( xMethod && pVTab->iSavepoint>iSavepoint ){
+          u64 savedFlags = (db->flags & SQLITE_Defensive);
+          db->flags &= ~(u64)SQLITE_Defensive;
+          rc = xMethod(pVTab->pVtab, iSavepoint);
+          db->flags |= savedFlags;
+        }
+        sqlite3VtabUnlock(pVTab);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** The first parameter (pDef) is a function implementation.  The
+** second parameter (pExpr) is the first argument to this function.
+** If pExpr is a column in a virtual table, then let the virtual
+** table implementation have an opportunity to overload the function.
+**
+** This routine is used to allow virtual table implementations to
+** overload MATCH, LIKE, GLOB, and REGEXP operators.
+**
+** Return either the pDef argument (indicating no change) or a
+** new FuncDef structure that is marked as ephemeral using the
+** SQLITE_FUNC_EPHEM flag.
+*/
+SQLITE_PRIVATE FuncDef *sqlite3VtabOverloadFunction(
+  sqlite3 *db,    /* Database connection for reporting malloc problems */
+  FuncDef *pDef,  /* Function to possibly overload */
+  int nArg,       /* Number of arguments to the function */
+  Expr *pExpr     /* First argument to the function */
+){
+  Table *pTab;
+  sqlite3_vtab *pVtab;
+  sqlite3_module *pMod;
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value**) = 0;
+  void *pArg = 0;
+  FuncDef *pNew;
+  int rc = 0;
+
+  /* Check to see the left operand is a column in a virtual table */
+  if( NEVER(pExpr==0) ) return pDef;
+  if( pExpr->op!=TK_COLUMN ) return pDef;
+  assert( ExprUseYTab(pExpr) );
+  pTab = pExpr->y.pTab;
+  if( NEVER(pTab==0) ) return pDef;
+  if( !IsVirtual(pTab) ) return pDef;
+  pVtab = sqlite3GetVTable(db, pTab)->pVtab;
+  assert( pVtab!=0 );
+  assert( pVtab->pModule!=0 );
+  pMod = (sqlite3_module *)pVtab->pModule;
+  if( pMod->xFindFunction==0 ) return pDef;
+
+  /* Call the xFindFunction method on the virtual table implementation
+  ** to see if the implementation wants to overload this function.
+  **
+  ** Though undocumented, we have historically always invoked xFindFunction
+  ** with an all lower-case function name.  Continue in this tradition to
+  ** avoid any chance of an incompatibility.
+  */
+#ifdef SQLITE_DEBUG
+  {
+    int i;
+    for(i=0; pDef->zName[i]; i++){
+      unsigned char x = (unsigned char)pDef->zName[i];
+      assert( x==sqlite3UpperToLower[x] );
+    }
+  }
+#endif
+  rc = pMod->xFindFunction(pVtab, nArg, pDef->zName, &xSFunc, &pArg);
+  if( rc==0 ){
+    return pDef;
+  }
+
+  /* Create a new ephemeral function definition for the overloaded
+  ** function */
+  pNew = sqlite3DbMallocZero(db, sizeof(*pNew)
+                             + sqlite3Strlen30(pDef->zName) + 1);
+  if( pNew==0 ){
+    return pDef;
+  }
+  *pNew = *pDef;
+  pNew->zName = (const char*)&pNew[1];
+  memcpy((char*)&pNew[1], pDef->zName, sqlite3Strlen30(pDef->zName)+1);
+  pNew->xSFunc = xSFunc;
+  pNew->pUserData = pArg;
+  pNew->funcFlags |= SQLITE_FUNC_EPHEM;
+  return pNew;
+}
+
+/*
+** Make sure virtual table pTab is contained in the pParse->apVirtualLock[]
+** array so that an OP_VBegin will get generated for it.  Add pTab to the
+** array if it is missing.  If pTab is already in the array, this routine
+** is a no-op.
+*/
+SQLITE_PRIVATE void sqlite3VtabMakeWritable(Parse *pParse, Table *pTab){
+  Parse *pToplevel = sqlite3ParseToplevel(pParse);
+  int i, n;
+  Table **apVtabLock;
+
+  assert( IsVirtual(pTab) );
+  for(i=0; i<pToplevel->nVtabLock; i++){
+    if( pTab==pToplevel->apVtabLock[i] ) return;
+  }
+  n = (pToplevel->nVtabLock+1)*sizeof(pToplevel->apVtabLock[0]);
+  apVtabLock = sqlite3Realloc(pToplevel->apVtabLock, n);
+  if( apVtabLock ){
+    pToplevel->apVtabLock = apVtabLock;
+    pToplevel->apVtabLock[pToplevel->nVtabLock++] = pTab;
+  }else{
+    sqlite3OomFault(pToplevel->db);
+  }
+}
+
+/*
+** Check to see if virtual table module pMod can be have an eponymous
+** virtual table instance.  If it can, create one if one does not already
+** exist. Return non-zero if either the eponymous virtual table instance
+** exists when this routine returns or if an attempt to create it failed
+** and an error message was left in pParse.
+**
+** An eponymous virtual table instance is one that is named after its
+** module, and more importantly, does not require a CREATE VIRTUAL TABLE
+** statement in order to come into existence.  Eponymous virtual table
+** instances always exist.  They cannot be DROP-ed.
+**
+** Any virtual table module for which xConnect and xCreate are the same
+** method can have an eponymous virtual table instance.
+*/
+SQLITE_PRIVATE int sqlite3VtabEponymousTableInit(Parse *pParse, Module *pMod){
+  const sqlite3_module *pModule = pMod->pModule;
+  Table *pTab;
+  char *zErr = 0;
+  int rc;
+  sqlite3 *db = pParse->db;
+  if( pMod->pEpoTab ) return 1;
+  if( pModule->xCreate!=0 && pModule->xCreate!=pModule->xConnect ) return 0;
+  pTab = sqlite3DbMallocZero(db, sizeof(Table));
+  if( pTab==0 ) return 0;
+  pTab->zName = sqlite3DbStrDup(db, pMod->zName);
+  if( pTab->zName==0 ){
+    sqlite3DbFree(db, pTab);
+    return 0;
+  }
+  pMod->pEpoTab = pTab;
+  pTab->nTabRef = 1;
+  pTab->eTabType = TABTYP_VTAB;
+  pTab->pSchema = db->aDb[0].pSchema;
+  assert( pTab->u.vtab.nArg==0 );
+  pTab->iPKey = -1;
+  pTab->tabFlags |= TF_Eponymous;
+  addModuleArgument(pParse, pTab, sqlite3DbStrDup(db, pTab->zName));
+  addModuleArgument(pParse, pTab, 0);
+  addModuleArgument(pParse, pTab, sqlite3DbStrDup(db, pTab->zName));
+  rc = vtabCallConstructor(db, pTab, pMod, pModule->xConnect, &zErr);
+  if( rc ){
+    sqlite3ErrorMsg(pParse, "%s", zErr);
+    sqlite3DbFree(db, zErr);
+    sqlite3VtabEponymousTableClear(db, pMod);
+  }
+  return 1;
+}
+
+/*
+** Erase the eponymous virtual table instance associated with
+** virtual table module pMod, if it exists.
+*/
+SQLITE_PRIVATE void sqlite3VtabEponymousTableClear(sqlite3 *db, Module *pMod){
+  Table *pTab = pMod->pEpoTab;
+  if( pTab!=0 ){
+    /* Mark the table as Ephemeral prior to deleting it, so that the
+    ** sqlite3DeleteTable() routine will know that it is not stored in
+    ** the schema. */
+    pTab->tabFlags |= TF_Ephemeral;
+    sqlite3DeleteTable(db, pTab);
+    pMod->pEpoTab = 0;
+  }
+}
+
+/*
+** Return the ON CONFLICT resolution mode in effect for the virtual
+** table update operation currently in progress.
+**
+** The results of this routine are undefined unless it is called from
+** within an xUpdate method.
+*/
+SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *db){
+  static const unsigned char aMap[] = {
+    SQLITE_ROLLBACK, SQLITE_ABORT, SQLITE_FAIL, SQLITE_IGNORE, SQLITE_REPLACE
+  };
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  assert( OE_Rollback==1 && OE_Abort==2 && OE_Fail==3 );
+  assert( OE_Ignore==4 && OE_Replace==5 );
+  assert( db->vtabOnConflict>=1 && db->vtabOnConflict<=5 );
+  return (int)aMap[db->vtabOnConflict-1];
+}
+
+/*
+** Call from within the xCreate() or xConnect() methods to provide
+** the SQLite core with additional information about the behavior
+** of the virtual table being implemented.
+*/
+SQLITE_API int sqlite3_vtab_config(sqlite3 *db, int op, ...){
+  va_list ap;
+  int rc = SQLITE_OK;
+  VtabCtx *p;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  p = db->pVtabCtx;
+  if( !p ){
+    rc = SQLITE_MISUSE_BKPT;
+  }else{
+    assert( p->pTab==0 || IsVirtual(p->pTab) );
+    va_start(ap, op);
+    switch( op ){
+      case SQLITE_VTAB_CONSTRAINT_SUPPORT: {
+        p->pVTable->bConstraint = (u8)va_arg(ap, int);
+        break;
+      }
+      case SQLITE_VTAB_INNOCUOUS: {
+        p->pVTable->eVtabRisk = SQLITE_VTABRISK_Low;
+        break;
+      }
+      case SQLITE_VTAB_DIRECTONLY: {
+        p->pVTable->eVtabRisk = SQLITE_VTABRISK_High;
+        break;
+      }
+      case SQLITE_VTAB_USES_ALL_SCHEMAS: {
+        p->pVTable->bAllSchemas = 1;
+        break;
+      }
+      default: {
+        rc = SQLITE_MISUSE_BKPT;
+        break;
+      }
+    }
+    va_end(ap);
+  }
+
+  if( rc!=SQLITE_OK ) sqlite3Error(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/************** End of vtab.c ************************************************/
+/************** Begin file wherecode.c ***************************************/
+/*
+** 2015-06-06
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This module contains C code that generates VDBE code used to process
+** the WHERE clause of SQL statements.
+**
+** This file was split off from where.c on 2015-06-06 in order to reduce the
+** size of where.c and make it easier to edit.  This file contains the routines
+** that actually generate the bulk of the WHERE loop code.  The original where.c
+** file retains the code that does query planning and analysis.
+*/
+/* #include "sqliteInt.h" */
+/************** Include whereInt.h in the middle of wherecode.c **************/
+/************** Begin file whereInt.h ****************************************/
+/*
+** 2013-11-12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains structure and macro definitions for the query
+** planner logic in "where.c".  These definitions are broken out into
+** a separate source file for easier editing.
+*/
+#ifndef SQLITE_WHEREINT_H
+#define SQLITE_WHEREINT_H
+
+
+/* Forward references
+*/
+typedef struct WhereClause WhereClause;
+typedef struct WhereMaskSet WhereMaskSet;
+typedef struct WhereOrInfo WhereOrInfo;
+typedef struct WhereAndInfo WhereAndInfo;
+typedef struct WhereLevel WhereLevel;
+typedef struct WhereLoop WhereLoop;
+typedef struct WherePath WherePath;
+typedef struct WhereTerm WhereTerm;
+typedef struct WhereLoopBuilder WhereLoopBuilder;
+typedef struct WhereScan WhereScan;
+typedef struct WhereOrCost WhereOrCost;
+typedef struct WhereOrSet WhereOrSet;
+typedef struct WhereMemBlock WhereMemBlock;
+typedef struct WhereRightJoin WhereRightJoin;
+
+/*
+** This object is a header on a block of allocated memory that will be
+** automatically freed when its WInfo object is destructed.
+*/
+struct WhereMemBlock {
+  WhereMemBlock *pNext;      /* Next block in the chain */
+  u64 sz;                    /* Bytes of space */
+};
+
+/*
+** Extra information attached to a WhereLevel that is a RIGHT JOIN.
+*/
+struct WhereRightJoin {
+  int iMatch;          /* Cursor used to determine prior matched rows */
+  int regBloom;        /* Bloom filter for iRJMatch */
+  int regReturn;       /* Return register for the interior subroutine */
+  int addrSubrtn;      /* Starting address for the interior subroutine */
+  int endSubrtn;       /* The last opcode in the interior subroutine */
+};
+
+/*
+** This object contains information needed to implement a single nested
+** loop in WHERE clause.
+**
+** Contrast this object with WhereLoop.  This object describes the
+** implementation of the loop.  WhereLoop describes the algorithm.
+** This object contains a pointer to the WhereLoop algorithm as one of
+** its elements.
+**
+** The WhereInfo object contains a single instance of this object for
+** each term in the FROM clause (which is to say, for each of the
+** nested loops as implemented).  The order of WhereLevel objects determines
+** the loop nested order, with WhereInfo.a[0] being the outer loop and
+** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop.
+*/
+struct WhereLevel {
+  int iLeftJoin;        /* Memory cell used to implement LEFT OUTER JOIN */
+  int iTabCur;          /* The VDBE cursor used to access the table */
+  int iIdxCur;          /* The VDBE cursor used to access pIdx */
+  int addrBrk;          /* Jump here to break out of the loop */
+  int addrNxt;          /* Jump here to start the next IN combination */
+  int addrSkip;         /* Jump here for next iteration of skip-scan */
+  int addrCont;         /* Jump here to continue with the next loop cycle */
+  int addrFirst;        /* First instruction of interior of the loop */
+  int addrBody;         /* Beginning of the body of this loop */
+  int regBignull;       /* big-null flag reg. True if a NULL-scan is needed */
+  int addrBignull;      /* Jump here for next part of big-null scan */
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+  u32 iLikeRepCntr;     /* LIKE range processing counter register (times 2) */
+  int addrLikeRep;      /* LIKE range processing address */
+#endif
+  int regFilter;        /* Bloom filter */
+  WhereRightJoin *pRJ;  /* Extra information for RIGHT JOIN */
+  u8 iFrom;             /* Which entry in the FROM clause */
+  u8 op, p3, p5;        /* Opcode, P3 & P5 of the opcode that ends the loop */
+  int p1, p2;           /* Operands of the opcode used to end the loop */
+  union {               /* Information that depends on pWLoop->wsFlags */
+    struct {
+      int nIn;              /* Number of entries in aInLoop[] */
+      struct InLoop {
+        int iCur;              /* The VDBE cursor used by this IN operator */
+        int addrInTop;         /* Top of the IN loop */
+        int iBase;             /* Base register of multi-key index record */
+        int nPrefix;           /* Number of prior entries in the key */
+        u8 eEndLoopOp;         /* IN Loop terminator. OP_Next or OP_Prev */
+      } *aInLoop;           /* Information about each nested IN operator */
+    } in;                 /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */
+    Index *pCoveringIdx;  /* Possible covering index for WHERE_MULTI_OR */
+  } u;
+  struct WhereLoop *pWLoop;  /* The selected WhereLoop object */
+  Bitmask notReady;          /* FROM entries not usable at this level */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrVisit;        /* Address at which row is visited */
+#endif
+};
+
+/*
+** Each instance of this object represents an algorithm for evaluating one
+** term of a join.  Every term of the FROM clause will have at least
+** one corresponding WhereLoop object (unless INDEXED BY constraints
+** prevent a query solution - which is an error) and many terms of the
+** FROM clause will have multiple WhereLoop objects, each describing a
+** potential way of implementing that FROM-clause term, together with
+** dependencies and cost estimates for using the chosen algorithm.
+**
+** Query planning consists of building up a collection of these WhereLoop
+** objects, then computing a particular sequence of WhereLoop objects, with
+** one WhereLoop object per FROM clause term, that satisfy all dependencies
+** and that minimize the overall cost.
+*/
+struct WhereLoop {
+  Bitmask prereq;       /* Bitmask of other loops that must run first */
+  Bitmask maskSelf;     /* Bitmask identifying table iTab */
+#ifdef SQLITE_DEBUG
+  char cId;             /* Symbolic ID of this loop for debugging use */
+#endif
+  u8 iTab;              /* Position in FROM clause of table for this loop */
+  u8 iSortIdx;          /* Sorting index number.  0==None */
+  LogEst rSetup;        /* One-time setup cost (ex: create transient index) */
+  LogEst rRun;          /* Cost of running each loop */
+  LogEst nOut;          /* Estimated number of output rows */
+  union {
+    struct {               /* Information for internal btree tables */
+      u16 nEq;               /* Number of equality constraints */
+      u16 nBtm;              /* Size of BTM vector */
+      u16 nTop;              /* Size of TOP vector */
+      u16 nDistinctCol;      /* Index columns used to sort for DISTINCT */
+      Index *pIndex;         /* Index used, or NULL */
+      ExprList *pOrderBy;    /* ORDER BY clause if this is really a subquery */
+    } btree;
+    struct {               /* Information for virtual tables */
+      int idxNum;            /* Index number */
+      u32 needFree : 1;      /* True if sqlite3_free(idxStr) is needed */
+      u32 bOmitOffset : 1;   /* True to let virtual table handle offset */
+      u32 bIdxNumHex : 1;    /* Show idxNum as hex in EXPLAIN QUERY PLAN */
+      i8 isOrdered;          /* True if satisfies ORDER BY */
+      u16 omitMask;          /* Terms that may be omitted */
+      char *idxStr;          /* Index identifier string */
+      u32 mHandleIn;         /* Terms to handle as IN(...) instead of == */
+    } vtab;
+  } u;
+  u32 wsFlags;          /* WHERE_* flags describing the plan */
+  u16 nLTerm;           /* Number of entries in aLTerm[] */
+  u16 nSkip;            /* Number of NULL aLTerm[] entries */
+  /**** whereLoopXfer() copies fields above ***********************/
+# define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot)
+  u16 nLSlot;           /* Number of slots allocated for aLTerm[] */
+#ifdef WHERETRACE_ENABLED
+  LogEst rStarDelta;    /* Cost delta due to star-schema heuristic.  Not
+                        ** initialized unless pWInfo->bStarUsed */
+#endif
+  WhereTerm **aLTerm;   /* WhereTerms used */
+  WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */
+  WhereTerm *aLTermSpace[3];  /* Initial aLTerm[] space */
+};
+
+/* This object holds the prerequisites and the cost of running a
+** subquery on one operand of an OR operator in the WHERE clause.
+** See WhereOrSet for additional information
+*/
+struct WhereOrCost {
+  Bitmask prereq;     /* Prerequisites */
+  LogEst rRun;        /* Cost of running this subquery */
+  LogEst nOut;        /* Number of outputs for this subquery */
+};
+
+/* The WhereOrSet object holds a set of possible WhereOrCosts that
+** correspond to the subquery(s) of OR-clause processing.  Only the
+** best N_OR_COST elements are retained.
+*/
+#define N_OR_COST 3
+struct WhereOrSet {
+  u16 n;                      /* Number of valid a[] entries */
+  WhereOrCost a[N_OR_COST];   /* Set of best costs */
+};
+
+/*
+** Each instance of this object holds a sequence of WhereLoop objects
+** that implement some or all of a query plan.
+**
+** Think of each WhereLoop object as a node in a graph with arcs
+** showing dependencies and costs for travelling between nodes.  (That is
+** not a completely accurate description because WhereLoop costs are a
+** vector, not a scalar, and because dependencies are many-to-one, not
+** one-to-one as are graph nodes.  But it is a useful visualization aid.)
+** Then a WherePath object is a path through the graph that visits some
+** or all of the WhereLoop objects once.
+**
+** The "solver" works by creating the N best WherePath objects of length
+** 1.  Then using those as a basis to compute the N best WherePath objects
+** of length 2.  And so forth until the length of WherePaths equals the
+** number of nodes in the FROM clause.  The best (lowest cost) WherePath
+** at the end is the chosen query plan.
+*/
+struct WherePath {
+  Bitmask maskLoop;     /* Bitmask of all WhereLoop objects in this path */
+  Bitmask revLoop;      /* aLoop[]s that should be reversed for ORDER BY */
+  LogEst nRow;          /* Estimated number of rows generated by this path */
+  LogEst rCost;         /* Total cost of this path */
+  LogEst rUnsort;       /* Total cost of this path ignoring sorting costs */
+  i8 isOrdered;         /* No. of ORDER BY terms satisfied. -1 for unknown */
+  WhereLoop **aLoop;    /* Array of WhereLoop objects implementing this path */
+};
+
+/*
+** The query generator uses an array of instances of this structure to
+** help it analyze the subexpressions of the WHERE clause.  Each WHERE
+** clause subexpression is separated from the others by AND operators,
+** usually, or sometimes subexpressions separated by OR.
+**
+** All WhereTerms are collected into a single WhereClause structure.
+** The following identity holds:
+**
+**        WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm
+**
+** When a term is of the form:
+**
+**              X <op> <expr>
+**
+** where X is a column name and <op> is one of certain operators,
+** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the
+** cursor number and column number for X.  WhereTerm.eOperator records
+** the <op> using a bitmask encoding defined by WO_xxx below.  The
+** use of a bitmask encoding for the operator allows us to search
+** quickly for terms that match any of several different operators.
+**
+** A WhereTerm might also be two or more subterms connected by OR:
+**
+**         (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR ....
+**
+** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR
+** and the WhereTerm.u.pOrInfo field points to auxiliary information that
+** is collected about the OR clause.
+**
+** If a term in the WHERE clause does not match either of the two previous
+** categories, then eOperator==0.  The WhereTerm.pExpr field is still set
+** to the original subexpression content and wtFlags is set up appropriately
+** but no other fields in the WhereTerm object are meaningful.
+**
+** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers,
+** but they do so indirectly.  A single WhereMaskSet structure translates
+** cursor number into bits and the translated bit is stored in the prereq
+** fields.  The translation is used in order to maximize the number of
+** bits that will fit in a Bitmask.  The VDBE cursor numbers might be
+** spread out over the non-negative integers.  For example, the cursor
+** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45.  The WhereMaskSet
+** translates these sparse cursor numbers into consecutive integers
+** beginning with 0 in order to make the best possible use of the available
+** bits in the Bitmask.  So, in the example above, the cursor numbers
+** would be mapped into integers 0 through 7.
+**
+** The number of terms in a join is limited by the number of bits
+** in prereqRight and prereqAll.  The default is 64 bits, hence SQLite
+** is only able to process joins with 64 or fewer tables.
+*/
+struct WhereTerm {
+  Expr *pExpr;            /* Pointer to the subexpression that is this term */
+  WhereClause *pWC;       /* The clause this term is part of */
+  LogEst truthProb;       /* Probability of truth for this expression */
+  u16 wtFlags;            /* TERM_xxx bit flags.  See below */
+  u16 eOperator;          /* A WO_xx value describing <op> */
+  u8 nChild;              /* Number of children that must disable us */
+  u8 eMatchOp;            /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */
+  int iParent;            /* Disable pWC->a[iParent] when this term disabled */
+  int leftCursor;         /* Cursor number of X in "X <op> <expr>" */
+  union {
+    struct {
+      int leftColumn;         /* Column number of X in "X <op> <expr>" */
+      int iField;             /* Field in (?,?,?) IN (SELECT...) vector */
+    } x;                    /* Opcode other than OP_OR or OP_AND */
+    WhereOrInfo *pOrInfo;   /* Extra information if (eOperator & WO_OR)!=0 */
+    WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */
+  } u;
+  Bitmask prereqRight;    /* Bitmask of tables used by pExpr->pRight */
+  Bitmask prereqAll;      /* Bitmask of tables referenced by pExpr */
+};
+
+/*
+** Allowed values of WhereTerm.wtFlags
+*/
+#define TERM_DYNAMIC    0x0001 /* Need to call sqlite3ExprDelete(db, pExpr) */
+#define TERM_VIRTUAL    0x0002 /* Added by the optimizer.  Do not code */
+#define TERM_CODED      0x0004 /* This term is already coded */
+#define TERM_COPIED     0x0008 /* Has a child */
+#define TERM_ORINFO     0x0010 /* Need to free the WhereTerm.u.pOrInfo object */
+#define TERM_ANDINFO    0x0020 /* Need to free the WhereTerm.u.pAndInfo obj */
+#define TERM_OK         0x0040 /* Used during OR-clause processing */
+#define TERM_VNULL      0x0080 /* Manufactured x>NULL or x<=NULL term */
+#define TERM_LIKEOPT    0x0100 /* Virtual terms from the LIKE optimization */
+#define TERM_LIKECOND   0x0200 /* Conditionally this LIKE operator term */
+#define TERM_LIKE       0x0400 /* The original LIKE operator */
+#define TERM_IS         0x0800 /* Term.pExpr is an IS operator */
+#define TERM_VARSELECT  0x1000 /* Term.pExpr contains a correlated sub-query */
+#define TERM_HEURTRUTH  0x2000 /* Heuristic truthProb used */
+#ifdef SQLITE_ENABLE_STAT4
+#  define TERM_HIGHTRUTH  0x4000 /* Term excludes few rows */
+#else
+#  define TERM_HIGHTRUTH  0      /* Only used with STAT4 */
+#endif
+#define TERM_SLICE      0x8000 /* One slice of a row-value/vector comparison */
+
+/*
+** An instance of the WhereScan object is used as an iterator for locating
+** terms in the WHERE clause that are useful to the query planner.
+*/
+struct WhereScan {
+  WhereClause *pOrigWC;      /* Original, innermost WhereClause */
+  WhereClause *pWC;          /* WhereClause currently being scanned */
+  const char *zCollName;     /* Required collating sequence, if not NULL */
+  Expr *pIdxExpr;            /* Search for this index expression */
+  int k;                     /* Resume scanning at this->pWC->a[this->k] */
+  u32 opMask;                /* Acceptable operators */
+  char idxaff;               /* Must match this affinity, if zCollName!=NULL */
+  unsigned char iEquiv;      /* Current slot in aiCur[] and aiColumn[] */
+  unsigned char nEquiv;      /* Number of entries in aiCur[] and aiColumn[] */
+  int aiCur[11];             /* Cursors in the equivalence class */
+  i16 aiColumn[11];          /* Corresponding column number in the eq-class */
+};
+
+/*
+** An instance of the following structure holds all information about a
+** WHERE clause.  Mostly this is a container for one or more WhereTerms.
+**
+** Explanation of pOuter:  For a WHERE clause of the form
+**
+**           a AND ((b AND c) OR (d AND e)) AND f
+**
+** There are separate WhereClause objects for the whole clause and for
+** the subclauses "(b AND c)" and "(d AND e)".  The pOuter field of the
+** subclauses points to the WhereClause object for the whole clause.
+*/
+struct WhereClause {
+  WhereInfo *pWInfo;       /* WHERE clause processing context */
+  WhereClause *pOuter;     /* Outer conjunction */
+  u8 op;                   /* Split operator.  TK_AND or TK_OR */
+  u8 hasOr;                /* True if any a[].eOperator is WO_OR */
+  int nTerm;               /* Number of terms */
+  int nSlot;               /* Number of entries in a[] */
+  int nBase;               /* Number of terms through the last non-Virtual */
+  WhereTerm *a;            /* Each a[] describes a term of the WHERE clause */
+#if defined(SQLITE_SMALL_STACK)
+  WhereTerm aStatic[1];    /* Initial static space for a[] */
+#else
+  WhereTerm aStatic[8];    /* Initial static space for a[] */
+#endif
+};
+
+/*
+** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to
+** a dynamically allocated instance of the following structure.
+*/
+struct WhereOrInfo {
+  WhereClause wc;          /* Decomposition into subterms */
+  Bitmask indexable;       /* Bitmask of all indexable tables in the clause */
+};
+
+/*
+** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to
+** a dynamically allocated instance of the following structure.
+*/
+struct WhereAndInfo {
+  WhereClause wc;          /* The subexpression broken out */
+};
+
+/*
+** An instance of the following structure keeps track of a mapping
+** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
+**
+** The VDBE cursor numbers are small integers contained in
+** SrcItem.iCursor and Expr.iTable fields.  For any given WHERE
+** clause, the cursor numbers might not begin with 0 and they might
+** contain gaps in the numbering sequence.  But we want to make maximum
+** use of the bits in our bitmasks.  This structure provides a mapping
+** from the sparse cursor numbers into consecutive integers beginning
+** with 0.
+**
+** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask
+** corresponds VDBE cursor number B.  The A-th bit of a bitmask is 1<<A.
+**
+** For example, if the WHERE clause expression used these VDBE
+** cursors:  4, 5, 8, 29, 57, 73.  Then the  WhereMaskSet structure
+** would map those cursor numbers into bits 0 through 5.
+**
+** Note that the mapping is not necessarily ordered.  In the example
+** above, the mapping might go like this:  4->3, 5->1, 8->2, 29->0,
+** 57->5, 73->4.  Or one of 719 other combinations might be used. It
+** does not really matter.  What is important is that sparse cursor
+** numbers all get mapped into bit numbers that begin with 0 and contain
+** no gaps.
+*/
+struct WhereMaskSet {
+  int bVarSelect;               /* Used by sqlite3WhereExprUsage() */
+  int n;                        /* Number of assigned cursor values */
+  int ix[BMS];                  /* Cursor assigned to each bit */
+};
+
+/*
+** This object is a convenience wrapper holding all information needed
+** to construct WhereLoop objects for a particular query.
+*/
+struct WhereLoopBuilder {
+  WhereInfo *pWInfo;        /* Information about this WHERE */
+  WhereClause *pWC;         /* WHERE clause terms */
+  WhereLoop *pNew;          /* Template WhereLoop */
+  WhereOrSet *pOrSet;       /* Record best loops here, if not NULL */
+#ifdef SQLITE_ENABLE_STAT4
+  UnpackedRecord *pRec;     /* Probe for stat4 (if required) */
+  int nRecValid;            /* Number of valid fields currently in pRec */
+#endif
+  unsigned char bldFlags1;  /* First set of SQLITE_BLDF_* flags */
+  unsigned char bldFlags2;  /* Second set of SQLITE_BLDF_* flags */
+  unsigned int iPlanLimit;  /* Search limiter */
+};
+
+/* Allowed values for WhereLoopBuider.bldFlags */
+#define SQLITE_BLDF1_INDEXED  0x0001   /* An index is used */
+#define SQLITE_BLDF1_UNIQUE   0x0002   /* All keys of a UNIQUE index used */
+
+#define SQLITE_BLDF2_2NDPASS  0x0004   /* Second builder pass needed */
+
+/* The WhereLoopBuilder.iPlanLimit is used to limit the number of
+** index+constraint combinations the query planner will consider for a
+** particular query.  If this parameter is unlimited, then certain
+** pathological queries can spend excess time in the sqlite3WhereBegin()
+** routine.  The limit is high enough that is should not impact real-world
+** queries.
+**
+** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit.  The limit is
+** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM
+** clause is processed, so that every table in a join is guaranteed to be
+** able to propose a some index+constraint combinations even if the initial
+** baseline limit was exhausted by prior tables of the join.
+*/
+#ifndef SQLITE_QUERY_PLANNER_LIMIT
+# define SQLITE_QUERY_PLANNER_LIMIT 20000
+#endif
+#ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR
+# define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000
+#endif
+
+/*
+** The WHERE clause processing routine has two halves.  The
+** first part does the start of the WHERE loop and the second
+** half does the tail of the WHERE loop.  An instance of
+** this structure is returned by the first half and passed
+** into the second half to give some continuity.
+**
+** An instance of this object holds the complete state of the query
+** planner.
+*/
+struct WhereInfo {
+  Parse *pParse;            /* Parsing and code generating context */
+  SrcList *pTabList;        /* List of tables in the join */
+  ExprList *pOrderBy;       /* The ORDER BY clause or NULL */
+  ExprList *pResultSet;     /* Result set of the query */
+#if WHERETRACE_ENABLED
+  Expr *pWhere;             /* The complete WHERE clause */
+#endif
+  Select *pSelect;          /* The entire SELECT statement containing WHERE */
+  int aiCurOnePass[2];      /* OP_OpenWrite cursors for the ONEPASS opt */
+  int iContinue;            /* Jump here to continue with next record */
+  int iBreak;               /* Jump here to break out of the loop */
+  int savedNQueryLoop;      /* pParse->nQueryLoop outside the WHERE loop */
+  u16 wctrlFlags;           /* Flags originally passed to sqlite3WhereBegin() */
+  LogEst iLimit;            /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */
+  u8 nLevel;                /* Number of nested loop */
+  i8 nOBSat;                /* Number of ORDER BY terms satisfied by indices */
+  u8 eOnePass;              /* ONEPASS_OFF, or _SINGLE, or _MULTI */
+  u8 eDistinct;             /* One of the WHERE_DISTINCT_* values */
+  unsigned bDeferredSeek :1;   /* Uses OP_DeferredSeek */
+  unsigned untestedTerms :1;   /* Not all WHERE terms resolved by outer loop */
+  unsigned bOrderedInnerLoop:1;/* True if only the inner-most loop is ordered */
+  unsigned sorted        :1;   /* True if really sorted (not just grouped) */
+  unsigned bStarDone     :1;   /* True if check for star-query is complete */
+  unsigned bStarUsed     :1;   /* True if star-query heuristic is used */
+  LogEst nRowOut;           /* Estimated number of output rows */
+#ifdef WHERETRACE_ENABLED
+  LogEst rTotalCost;        /* Total cost of the solution */
+#endif
+  int iTop;                 /* The very beginning of the WHERE loop */
+  int iEndWhere;            /* End of the WHERE clause itself */
+  WhereLoop *pLoops;        /* List of all WhereLoop objects */
+  WhereMemBlock *pMemToFree;/* Memory to free when this object destroyed */
+  Bitmask revMask;          /* Mask of ORDER BY terms that need reversing */
+  WhereClause sWC;          /* Decomposition of the WHERE clause */
+  WhereMaskSet sMaskSet;    /* Map cursor numbers to bitmasks */
+  WhereLevel a[1];          /* Information about each nest loop in WHERE */
+};
+
+/*
+** Private interfaces - callable only by other where.c routines.
+**
+** where.c:
+*/
+SQLITE_PRIVATE Bitmask sqlite3WhereGetMask(WhereMaskSet*,int);
+#ifdef WHERETRACE_ENABLED
+SQLITE_PRIVATE void sqlite3WhereClausePrint(WhereClause *pWC);
+SQLITE_PRIVATE void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm);
+SQLITE_PRIVATE void sqlite3WhereLoopPrint(const WhereLoop *p, const WhereClause *pWC);
+#endif
+SQLITE_PRIVATE WhereTerm *sqlite3WhereFindTerm(
+  WhereClause *pWC,     /* The WHERE clause to be searched */
+  int iCur,             /* Cursor number of LHS */
+  int iColumn,          /* Column number of LHS */
+  Bitmask notReady,     /* RHS must not overlap with this mask */
+  u32 op,               /* Mask of WO_xx values describing operator */
+  Index *pIdx           /* Must be compatible with this index, if not NULL */
+);
+SQLITE_PRIVATE void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte);
+SQLITE_PRIVATE void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte);
+
+/* wherecode.c: */
+#ifndef SQLITE_OMIT_EXPLAIN
+SQLITE_PRIVATE int sqlite3WhereExplainOneScan(
+  Parse *pParse,                  /* Parse context */
+  SrcList *pTabList,              /* Table list this loop refers to */
+  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
+  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
+);
+SQLITE_PRIVATE int sqlite3WhereExplainBloomFilter(
+  const Parse *pParse,            /* Parse context */
+  const WhereInfo *pWInfo,        /* WHERE clause */
+  const WhereLevel *pLevel        /* Bloom filter on this level */
+);
+SQLITE_PRIVATE void sqlite3WhereAddExplainText(
+  Parse *pParse,                  /* Parse context */
+  int addr,
+  SrcList *pTabList,              /* Table list this loop refers to */
+  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
+  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
+);
+#else
+# define sqlite3WhereExplainOneScan(u,v,w,x) 0
+# define sqlite3WhereExplainBloomFilter(u,v,w) 0
+# define  sqlite3WhereAddExplainText(u,v,w,x,y)
+#endif /* SQLITE_OMIT_EXPLAIN */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+SQLITE_PRIVATE void sqlite3WhereAddScanStatus(
+  Vdbe *v,                        /* Vdbe to add scanstatus entry to */
+  SrcList *pSrclist,              /* FROM clause pLvl reads data from */
+  WhereLevel *pLvl,               /* Level to add scanstatus() entry for */
+  int addrExplain                 /* Address of OP_Explain (or 0) */
+);
+#else
+# define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d)
+#endif
+SQLITE_PRIVATE Bitmask sqlite3WhereCodeOneLoopStart(
+  Parse *pParse,       /* Parsing context */
+  Vdbe *v,             /* Prepared statement under construction */
+  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
+  int iLevel,          /* Which level of pWInfo->a[] should be coded */
+  WhereLevel *pLevel,  /* The current level pointer */
+  Bitmask notReady     /* Which tables are currently available */
+);
+SQLITE_PRIVATE SQLITE_NOINLINE void sqlite3WhereRightJoinLoop(
+  WhereInfo *pWInfo,
+  int iLevel,
+  WhereLevel *pLevel
+);
+
+/* whereexpr.c: */
+SQLITE_PRIVATE void sqlite3WhereClauseInit(WhereClause*,WhereInfo*);
+SQLITE_PRIVATE void sqlite3WhereClauseClear(WhereClause*);
+SQLITE_PRIVATE void sqlite3WhereSplit(WhereClause*,Expr*,u8);
+SQLITE_PRIVATE void sqlite3WhereAddLimit(WhereClause*, Select*);
+SQLITE_PRIVATE Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*);
+SQLITE_PRIVATE Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*);
+SQLITE_PRIVATE Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*);
+SQLITE_PRIVATE void sqlite3WhereExprAnalyze(SrcList*, WhereClause*);
+SQLITE_PRIVATE void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*);
+
+
+
+
+
+/*
+** Bitmasks for the operators on WhereTerm objects.  These are all
+** operators that are of interest to the query planner.  An
+** OR-ed combination of these values can be used when searching for
+** particular WhereTerms within a WhereClause.
+**
+** Value constraints:
+**     WO_EQ    == SQLITE_INDEX_CONSTRAINT_EQ
+**     WO_LT    == SQLITE_INDEX_CONSTRAINT_LT
+**     WO_LE    == SQLITE_INDEX_CONSTRAINT_LE
+**     WO_GT    == SQLITE_INDEX_CONSTRAINT_GT
+**     WO_GE    == SQLITE_INDEX_CONSTRAINT_GE
+*/
+#define WO_IN     0x0001
+#define WO_EQ     0x0002
+#define WO_LT     (WO_EQ<<(TK_LT-TK_EQ))
+#define WO_LE     (WO_EQ<<(TK_LE-TK_EQ))
+#define WO_GT     (WO_EQ<<(TK_GT-TK_EQ))
+#define WO_GE     (WO_EQ<<(TK_GE-TK_EQ))
+#define WO_AUX    0x0040       /* Op useful to virtual tables only */
+#define WO_IS     0x0080
+#define WO_ISNULL 0x0100
+#define WO_OR     0x0200       /* Two or more OR-connected terms */
+#define WO_AND    0x0400       /* Two or more AND-connected terms */
+#define WO_EQUIV  0x0800       /* Of the form A==B, both columns */
+#define WO_NOOP   0x1000       /* This term does not restrict search space */
+#define WO_ROWVAL 0x2000       /* A row-value term */
+
+#define WO_ALL    0x3fff       /* Mask of all possible WO_* values */
+#define WO_SINGLE 0x01ff       /* Mask of all non-compound WO_* values */
+
+/*
+** These are definitions of bits in the WhereLoop.wsFlags field.
+** The particular combination of bits in each WhereLoop help to
+** determine the algorithm that WhereLoop represents.
+*/
+#define WHERE_COLUMN_EQ    0x00000001  /* x=EXPR */
+#define WHERE_COLUMN_RANGE 0x00000002  /* x<EXPR and/or x>EXPR */
+#define WHERE_COLUMN_IN    0x00000004  /* x IN (...) */
+#define WHERE_COLUMN_NULL  0x00000008  /* x IS NULL */
+#define WHERE_CONSTRAINT   0x0000000f  /* Any of the WHERE_COLUMN_xxx values */
+#define WHERE_TOP_LIMIT    0x00000010  /* x<EXPR or x<=EXPR constraint */
+#define WHERE_BTM_LIMIT    0x00000020  /* x>EXPR or x>=EXPR constraint */
+#define WHERE_BOTH_LIMIT   0x00000030  /* Both x>EXPR and x<EXPR */
+#define WHERE_IDX_ONLY     0x00000040  /* Use index only - omit table */
+#define WHERE_IPK          0x00000100  /* x is the INTEGER PRIMARY KEY */
+#define WHERE_INDEXED      0x00000200  /* WhereLoop.u.btree.pIndex is valid */
+#define WHERE_VIRTUALTABLE 0x00000400  /* WhereLoop.u.vtab is valid */
+#define WHERE_IN_ABLE      0x00000800  /* Able to support an IN operator */
+#define WHERE_ONEROW       0x00001000  /* Selects no more than one row */
+#define WHERE_MULTI_OR     0x00002000  /* OR using multiple indices */
+#define WHERE_AUTO_INDEX   0x00004000  /* Uses an ephemeral index */
+#define WHERE_SKIPSCAN     0x00008000  /* Uses the skip-scan algorithm */
+#define WHERE_UNQ_WANTED   0x00010000  /* WHERE_ONEROW would have been helpful*/
+#define WHERE_PARTIALIDX   0x00020000  /* The automatic index is partial */
+#define WHERE_IN_EARLYOUT  0x00040000  /* Perhaps quit IN loops early */
+#define WHERE_BIGNULL_SORT 0x00080000  /* Column nEq of index is BIGNULL */
+#define WHERE_IN_SEEKSCAN  0x00100000  /* Seek-scan optimization for IN */
+#define WHERE_TRANSCONS    0x00200000  /* Uses a transitive constraint */
+#define WHERE_BLOOMFILTER  0x00400000  /* Consider using a Bloom-filter */
+#define WHERE_SELFCULL     0x00800000  /* nOut reduced by extra WHERE terms */
+#define WHERE_OMIT_OFFSET  0x01000000  /* Set offset counter to zero */
+#define WHERE_COROUTINE    0x02000000  /* Implemented by co-routine.
+                                       ** NB: False-negatives are possible */
+#define WHERE_EXPRIDX      0x04000000  /* Uses an index-on-expressions */
+
+#endif /* !defined(SQLITE_WHEREINT_H) */
+
+/************** End of whereInt.h ********************************************/
+/************** Continuing where we left off in wherecode.c ******************/
+
+#ifndef SQLITE_OMIT_EXPLAIN
+
+/*
+** Return the name of the i-th column of the pIdx index.
+*/
+static const char *explainIndexColumnName(Index *pIdx, int i){
+  i = pIdx->aiColumn[i];
+  if( i==XN_EXPR ) return "<expr>";
+  if( i==XN_ROWID ) return "rowid";
+  return pIdx->pTable->aCol[i].zCnName;
+}
+
+/*
+** This routine is a helper for explainIndexRange() below
+**
+** pStr holds the text of an expression that we are building up one term
+** at a time.  This routine adds a new term to the end of the expression.
+** Terms are separated by AND so add the "AND" text for second and subsequent
+** terms only.
+*/
+static void explainAppendTerm(
+  StrAccum *pStr,             /* The text expression being built */
+  Index *pIdx,                /* Index to read column names from */
+  int nTerm,                  /* Number of terms */
+  int iTerm,                  /* Zero-based index of first term. */
+  int bAnd,                   /* Non-zero to append " AND " */
+  const char *zOp             /* Name of the operator */
+){
+  int i;
+
+  assert( nTerm>=1 );
+  if( bAnd ) sqlite3_str_append(pStr, " AND ", 5);
+
+  if( nTerm>1 ) sqlite3_str_append(pStr, "(", 1);
+  for(i=0; i<nTerm; i++){
+    if( i ) sqlite3_str_append(pStr, ",", 1);
+    sqlite3_str_appendall(pStr, explainIndexColumnName(pIdx, iTerm+i));
+  }
+  if( nTerm>1 ) sqlite3_str_append(pStr, ")", 1);
+
+  sqlite3_str_append(pStr, zOp, 1);
+
+  if( nTerm>1 ) sqlite3_str_append(pStr, "(", 1);
+  for(i=0; i<nTerm; i++){
+    if( i ) sqlite3_str_append(pStr, ",", 1);
+    sqlite3_str_append(pStr, "?", 1);
+  }
+  if( nTerm>1 ) sqlite3_str_append(pStr, ")", 1);
+}
+
+/*
+** Argument pLevel describes a strategy for scanning table pTab. This
+** function appends text to pStr that describes the subset of table
+** rows scanned by the strategy in the form of an SQL expression.
+**
+** For example, if the query:
+**
+**   SELECT * FROM t1 WHERE a=1 AND b>2;
+**
+** is run and there is an index on (a, b), then this function returns a
+** string similar to:
+**
+**   "a=? AND b>?"
+*/
+static void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop){
+  Index *pIndex = pLoop->u.btree.pIndex;
+  u16 nEq = pLoop->u.btree.nEq;
+  u16 nSkip = pLoop->nSkip;
+  int i, j;
+
+  if( nEq==0 && (pLoop->wsFlags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ) return;
+  sqlite3_str_append(pStr, " (", 2);
+  for(i=0; i<nEq; i++){
+    const char *z = explainIndexColumnName(pIndex, i);
+    if( i ) sqlite3_str_append(pStr, " AND ", 5);
+    sqlite3_str_appendf(pStr, i>=nSkip ? "%s=?" : "ANY(%s)", z);
+  }
+
+  j = i;
+  if( pLoop->wsFlags&WHERE_BTM_LIMIT ){
+    explainAppendTerm(pStr, pIndex, pLoop->u.btree.nBtm, j, i, ">");
+    i = 1;
+  }
+  if( pLoop->wsFlags&WHERE_TOP_LIMIT ){
+    explainAppendTerm(pStr, pIndex, pLoop->u.btree.nTop, j, i, "<");
+  }
+  sqlite3_str_append(pStr, ")", 1);
+}
+
+/*
+** This function sets the P4 value of an existing OP_Explain opcode to
+** text describing the loop in pLevel. If the OP_Explain opcode already has
+** a P4 value, it is freed before it is overwritten.
+*/
+SQLITE_PRIVATE void sqlite3WhereAddExplainText(
+  Parse *pParse,                  /* Parse context */
+  int addr,                       /* Address of OP_Explain opcode */
+  SrcList *pTabList,              /* Table list this loop refers to */
+  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
+  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
+){
+#if !defined(SQLITE_DEBUG)
+  if( sqlite3ParseToplevel(pParse)->explain==2 || IS_STMT_SCANSTATUS(pParse->db) )
+#endif
+  {
+    VdbeOp *pOp = sqlite3VdbeGetOp(pParse->pVdbe, addr);
+
+    SrcItem *pItem = &pTabList->a[pLevel->iFrom];
+    sqlite3 *db = pParse->db;     /* Database handle */
+    int isSearch;                 /* True for a SEARCH. False for SCAN. */
+    WhereLoop *pLoop;             /* The controlling WhereLoop object */
+    u32 flags;                    /* Flags that describe this loop */
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_EXPLAIN)
+    char *zMsg;                   /* Text to add to EQP output */
+#endif
+    StrAccum str;                 /* EQP output string */
+    char zBuf[100];               /* Initial space for EQP output string */
+
+    if( db->mallocFailed ) return;
+
+    pLoop = pLevel->pWLoop;
+    flags = pLoop->wsFlags;
+
+    isSearch = (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0
+            || ((flags&WHERE_VIRTUALTABLE)==0 && (pLoop->u.btree.nEq>0))
+            || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX));
+
+    sqlite3StrAccumInit(&str, db, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH);
+    str.printfFlags = SQLITE_PRINTF_INTERNAL;
+    sqlite3_str_appendf(&str, "%s %S", isSearch ? "SEARCH" : "SCAN", pItem);
+    if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0 ){
+      const char *zFmt = 0;
+      Index *pIdx;
+
+      assert( pLoop->u.btree.pIndex!=0 );
+      pIdx = pLoop->u.btree.pIndex;
+      assert( !(flags&WHERE_AUTO_INDEX) || (flags&WHERE_IDX_ONLY) );
+      if( !HasRowid(pItem->pSTab) && IsPrimaryKeyIndex(pIdx) ){
+        if( isSearch ){
+          zFmt = "PRIMARY KEY";
+        }
+      }else if( flags & WHERE_PARTIALIDX ){
+        zFmt = "AUTOMATIC PARTIAL COVERING INDEX";
+      }else if( flags & WHERE_AUTO_INDEX ){
+        zFmt = "AUTOMATIC COVERING INDEX";
+      }else if( flags & (WHERE_IDX_ONLY|WHERE_EXPRIDX) ){
+        zFmt = "COVERING INDEX %s";
+      }else{
+        zFmt = "INDEX %s";
+      }
+      if( zFmt ){
+        sqlite3_str_append(&str, " USING ", 7);
+        sqlite3_str_appendf(&str, zFmt, pIdx->zName);
+        explainIndexRange(&str, pLoop);
+      }
+    }else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){
+      char cRangeOp;
+#if 0  /* Better output, but breaks many tests */
+      const Table *pTab = pItem->pTab;
+      const char *zRowid = pTab->iPKey>=0 ? pTab->aCol[pTab->iPKey].zCnName:
+                              "rowid";
+#else
+      const char *zRowid = "rowid";
+#endif
+      sqlite3_str_appendf(&str, " USING INTEGER PRIMARY KEY (%s", zRowid);
+      if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){
+        cRangeOp = '=';
+      }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){
+        sqlite3_str_appendf(&str, ">? AND %s", zRowid);
+        cRangeOp = '<';
+      }else if( flags&WHERE_BTM_LIMIT ){
+        cRangeOp = '>';
+      }else{
+        assert( flags&WHERE_TOP_LIMIT);
+        cRangeOp = '<';
+      }
+      sqlite3_str_appendf(&str, "%c?)", cRangeOp);
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    else if( (flags & WHERE_VIRTUALTABLE)!=0 ){
+      sqlite3_str_appendall(&str, " VIRTUAL TABLE INDEX ");
+      sqlite3_str_appendf(&str,
+                  pLoop->u.vtab.bIdxNumHex ? "0x%x:%s" : "%d:%s",
+                  pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr);
+    }
+#endif
+    if( pItem->fg.jointype & JT_LEFT ){
+      sqlite3_str_appendf(&str, " LEFT-JOIN");
+    }
+#ifdef SQLITE_EXPLAIN_ESTIMATED_ROWS
+    if( pLoop->nOut>=10 ){
+      sqlite3_str_appendf(&str, " (~%llu rows)",
+             sqlite3LogEstToInt(pLoop->nOut));
+    }else{
+      sqlite3_str_append(&str, " (~1 row)", 9);
+    }
+#endif
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_EXPLAIN)
+    zMsg = sqlite3StrAccumFinish(&str);
+    sqlite3ExplainBreakpoint("",zMsg);
+#endif
+
+    assert( pOp->opcode==OP_Explain );
+    assert( pOp->p4type==P4_DYNAMIC || pOp->p4.z==0 );
+    sqlite3DbFree(db, pOp->p4.z);
+    pOp->p4type = P4_DYNAMIC;
+    pOp->p4.z = sqlite3StrAccumFinish(&str);
+  }
+}
+
+
+/*
+** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN
+** command, or if stmt_scanstatus_v2() stats are enabled, or if SQLITE_DEBUG
+** was defined at compile-time. If it is not a no-op, a single OP_Explain
+** opcode is added to the output to describe the table scan strategy in pLevel.
+**
+** If an OP_Explain opcode is added to the VM, its address is returned.
+** Otherwise, if no OP_Explain is coded, zero is returned.
+*/
+SQLITE_PRIVATE int sqlite3WhereExplainOneScan(
+  Parse *pParse,                  /* Parse context */
+  SrcList *pTabList,              /* Table list this loop refers to */
+  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
+  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
+){
+  int ret = 0;
+#if !defined(SQLITE_DEBUG)
+  if( sqlite3ParseToplevel(pParse)->explain==2 || IS_STMT_SCANSTATUS(pParse->db) )
+#endif
+  {
+    if( (pLevel->pWLoop->wsFlags & WHERE_MULTI_OR)==0
+     && (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
+    ){
+      Vdbe *v = pParse->pVdbe;
+      int addr = sqlite3VdbeCurrentAddr(v);
+      ret = sqlite3VdbeAddOp3(
+          v, OP_Explain, addr, pParse->addrExplain, pLevel->pWLoop->rRun
+      );
+      sqlite3WhereAddExplainText(pParse, addr, pTabList, pLevel, wctrlFlags);
+    }
+  }
+  return ret;
+}
+
+/*
+** Add a single OP_Explain opcode that describes a Bloom filter.
+**
+** Or if not processing EXPLAIN QUERY PLAN and not in a SQLITE_DEBUG and/or
+** SQLITE_ENABLE_STMT_SCANSTATUS build, then OP_Explain opcodes are not
+** required and this routine is a no-op.
+**
+** If an OP_Explain opcode is added to the VM, its address is returned.
+** Otherwise, if no OP_Explain is coded, zero is returned.
+*/
+SQLITE_PRIVATE int sqlite3WhereExplainBloomFilter(
+  const Parse *pParse,               /* Parse context */
+  const WhereInfo *pWInfo,           /* WHERE clause */
+  const WhereLevel *pLevel           /* Bloom filter on this level */
+){
+  int ret = 0;
+  SrcItem *pItem = &pWInfo->pTabList->a[pLevel->iFrom];
+  Vdbe *v = pParse->pVdbe;      /* VM being constructed */
+  sqlite3 *db = pParse->db;     /* Database handle */
+  char *zMsg;                   /* Text to add to EQP output */
+  int i;                        /* Loop counter */
+  WhereLoop *pLoop;             /* The where loop */
+  StrAccum str;                 /* EQP output string */
+  char zBuf[100];               /* Initial space for EQP output string */
+
+  sqlite3StrAccumInit(&str, db, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH);
+  str.printfFlags = SQLITE_PRINTF_INTERNAL;
+  sqlite3_str_appendf(&str, "BLOOM FILTER ON %S (", pItem);
+  pLoop = pLevel->pWLoop;
+  if( pLoop->wsFlags & WHERE_IPK ){
+    const Table *pTab = pItem->pSTab;
+    if( pTab->iPKey>=0 ){
+      sqlite3_str_appendf(&str, "%s=?", pTab->aCol[pTab->iPKey].zCnName);
+    }else{
+      sqlite3_str_appendf(&str, "rowid=?");
+    }
+  }else{
+    for(i=pLoop->nSkip; i<pLoop->u.btree.nEq; i++){
+      const char *z = explainIndexColumnName(pLoop->u.btree.pIndex, i);
+      if( i>pLoop->nSkip ) sqlite3_str_append(&str, " AND ", 5);
+      sqlite3_str_appendf(&str, "%s=?", z);
+    }
+  }
+  sqlite3_str_append(&str, ")", 1);
+  zMsg = sqlite3StrAccumFinish(&str);
+  ret = sqlite3VdbeAddOp4(v, OP_Explain, sqlite3VdbeCurrentAddr(v),
+                          pParse->addrExplain, 0, zMsg,P4_DYNAMIC);
+
+  sqlite3VdbeScanStatus(v, sqlite3VdbeCurrentAddr(v)-1, 0, 0, 0, 0);
+  return ret;
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+/*
+** Configure the VM passed as the first argument with an
+** sqlite3_stmt_scanstatus() entry corresponding to the scan used to
+** implement level pLvl. Argument pSrclist is a pointer to the FROM
+** clause that the scan reads data from.
+**
+** If argument addrExplain is not 0, it must be the address of an
+** OP_Explain instruction that describes the same loop.
+*/
+SQLITE_PRIVATE void sqlite3WhereAddScanStatus(
+  Vdbe *v,                        /* Vdbe to add scanstatus entry to */
+  SrcList *pSrclist,              /* FROM clause pLvl reads data from */
+  WhereLevel *pLvl,               /* Level to add scanstatus() entry for */
+  int addrExplain                 /* Address of OP_Explain (or 0) */
+){
+  if( IS_STMT_SCANSTATUS( sqlite3VdbeDb(v) ) ){
+    const char *zObj = 0;
+    WhereLoop *pLoop = pLvl->pWLoop;
+    int wsFlags = pLoop->wsFlags;
+    int viaCoroutine = 0;
+
+    if( (wsFlags & WHERE_VIRTUALTABLE)==0  &&  pLoop->u.btree.pIndex!=0 ){
+      zObj = pLoop->u.btree.pIndex->zName;
+    }else{
+      zObj = pSrclist->a[pLvl->iFrom].zName;
+      viaCoroutine = pSrclist->a[pLvl->iFrom].fg.viaCoroutine;
+    }
+    sqlite3VdbeScanStatus(
+        v, addrExplain, pLvl->addrBody, pLvl->addrVisit, pLoop->nOut, zObj
+    );
+
+    if( viaCoroutine==0 ){
+      if( (wsFlags & (WHERE_MULTI_OR|WHERE_AUTO_INDEX))==0 ){
+        sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iTabCur);
+      }
+      if( wsFlags & WHERE_INDEXED ){
+        sqlite3VdbeScanStatusRange(v, addrExplain, -1, pLvl->iIdxCur);
+      }
+    }else{
+      int addr;
+      VdbeOp *pOp;
+      assert( pSrclist->a[pLvl->iFrom].fg.isSubquery );
+      addr = pSrclist->a[pLvl->iFrom].u4.pSubq->addrFillSub;
+      pOp = sqlite3VdbeGetOp(v, addr-1);
+      assert( sqlite3VdbeDb(v)->mallocFailed || pOp->opcode==OP_InitCoroutine );
+      assert( sqlite3VdbeDb(v)->mallocFailed || pOp->p2>addr );
+      sqlite3VdbeScanStatusRange(v, addrExplain, addr, pOp->p2-1);
+    }
+  }
+}
+#endif
+
+
+/*
+** Disable a term in the WHERE clause.  Except, do not disable the term
+** if it controls a LEFT OUTER JOIN and it did not originate in the ON
+** or USING clause of that join.
+**
+** Consider the term t2.z='ok' in the following queries:
+**
+**   (1)  SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x WHERE t2.z='ok'
+**   (2)  SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x AND t2.z='ok'
+**   (3)  SELECT * FROM t1, t2 WHERE t1.a=t2.x AND t2.z='ok'
+**
+** The t2.z='ok' is disabled in the in (2) because it originates
+** in the ON clause.  The term is disabled in (3) because it is not part
+** of a LEFT OUTER JOIN.  In (1), the term is not disabled.
+**
+** Disabling a term causes that term to not be tested in the inner loop
+** of the join.  Disabling is an optimization.  When terms are satisfied
+** by indices, we disable them to prevent redundant tests in the inner
+** loop.  We would get the correct results if nothing were ever disabled,
+** but joins might run a little slower.  The trick is to disable as much
+** as we can without disabling too much.  If we disabled in (1), we'd get
+** the wrong answer.  See ticket #813.
+**
+** If all the children of a term are disabled, then that term is also
+** automatically disabled.  In this way, terms get disabled if derived
+** virtual terms are tested first.  For example:
+**
+**      x GLOB 'abc*' AND x>='abc' AND x<'acd'
+**      \___________/     \______/     \_____/
+**         parent          child1       child2
+**
+** Only the parent term was in the original WHERE clause.  The child1
+** and child2 terms were added by the LIKE optimization.  If both of
+** the virtual child terms are valid, then testing of the parent can be
+** skipped.
+**
+** Usually the parent term is marked as TERM_CODED.  But if the parent
+** term was originally TERM_LIKE, then the parent gets TERM_LIKECOND instead.
+** The TERM_LIKECOND marking indicates that the term should be coded inside
+** a conditional such that is only evaluated on the second pass of a
+** LIKE-optimization loop, when scanning BLOBs instead of strings.
+*/
+static void disableTerm(WhereLevel *pLevel, WhereTerm *pTerm){
+  int nLoop = 0;
+  assert( pTerm!=0 );
+  while( (pTerm->wtFlags & TERM_CODED)==0
+      && (pLevel->iLeftJoin==0 || ExprHasProperty(pTerm->pExpr, EP_OuterON))
+      && (pLevel->notReady & pTerm->prereqAll)==0
+  ){
+    if( nLoop && (pTerm->wtFlags & TERM_LIKE)!=0 ){
+      pTerm->wtFlags |= TERM_LIKECOND;
+    }else{
+      pTerm->wtFlags |= TERM_CODED;
+    }
+#ifdef WHERETRACE_ENABLED
+    if( (sqlite3WhereTrace & 0x4001)==0x4001 ){
+      sqlite3DebugPrintf("DISABLE-");
+      sqlite3WhereTermPrint(pTerm, (int)(pTerm - (pTerm->pWC->a)));
+    }
+#endif
+    if( pTerm->iParent<0 ) break;
+    pTerm = &pTerm->pWC->a[pTerm->iParent];
+    assert( pTerm!=0 );
+    pTerm->nChild--;
+    if( pTerm->nChild!=0 ) break;
+    nLoop++;
+  }
+}
+
+/*
+** Code an OP_Affinity opcode to apply the column affinity string zAff
+** to the n registers starting at base.
+**
+** As an optimization, SQLITE_AFF_BLOB and SQLITE_AFF_NONE entries (which
+** are no-ops) at the beginning and end of zAff are ignored.  If all entries
+** in zAff are SQLITE_AFF_BLOB or SQLITE_AFF_NONE, then no code gets generated.
+**
+** This routine makes its own copy of zAff so that the caller is free
+** to modify zAff after this routine returns.
+*/
+static void codeApplyAffinity(Parse *pParse, int base, int n, char *zAff){
+  Vdbe *v = pParse->pVdbe;
+  if( zAff==0 ){
+    assert( pParse->db->mallocFailed );
+    return;
+  }
+  assert( v!=0 );
+
+  /* Adjust base and n to skip over SQLITE_AFF_BLOB and SQLITE_AFF_NONE
+  ** entries at the beginning and end of the affinity string.
+  */
+  assert( SQLITE_AFF_NONE<SQLITE_AFF_BLOB );
+  while( n>0 && zAff[0]<=SQLITE_AFF_BLOB ){
+    n--;
+    base++;
+    zAff++;
+  }
+  while( n>1 && zAff[n-1]<=SQLITE_AFF_BLOB ){
+    n--;
+  }
+
+  /* Code the OP_Affinity opcode if there is anything left to do. */
+  if( n>0 ){
+    sqlite3VdbeAddOp4(v, OP_Affinity, base, n, 0, zAff, n);
+  }
+}
+
+/*
+** Expression pRight, which is the RHS of a comparison operation, is
+** either a vector of n elements or, if n==1, a scalar expression.
+** Before the comparison operation, affinity zAff is to be applied
+** to the pRight values. This function modifies characters within the
+** affinity string to SQLITE_AFF_BLOB if either:
+**
+**   * the comparison will be performed with no affinity, or
+**   * the affinity change in zAff is guaranteed not to change the value.
+*/
+static void updateRangeAffinityStr(
+  Expr *pRight,                   /* RHS of comparison */
+  int n,                          /* Number of vector elements in comparison */
+  char *zAff                      /* Affinity string to modify */
+){
+  int i;
+  for(i=0; i<n; i++){
+    Expr *p = sqlite3VectorFieldSubexpr(pRight, i);
+    if( sqlite3CompareAffinity(p, zAff[i])==SQLITE_AFF_BLOB
+     || sqlite3ExprNeedsNoAffinityChange(p, zAff[i])
+    ){
+      zAff[i] = SQLITE_AFF_BLOB;
+    }
+  }
+}
+
+/*
+** The pOrderBy->a[].u.x.iOrderByCol values might be incorrect because
+** columns might have been rearranged in the result set.  This routine
+** fixes them up.
+**
+** pEList is the new result set.  The pEList->a[].u.x.iOrderByCol values
+** contain the *old* locations of each expression.  This is a temporary
+** use of u.x.iOrderByCol, not its intended use.  The caller must reset
+** u.x.iOrderByCol back to zero for all entries in pEList before the
+** caller returns.
+**
+** This routine changes pOrderBy->a[].u.x.iOrderByCol values from
+** pEList->a[N].u.x.iOrderByCol into N+1.  (The "+1" is because of the 1-based
+** indexing used by iOrderByCol.)  Or if no match, iOrderByCol is set to zero.
+*/
+static void adjustOrderByCol(ExprList *pOrderBy, ExprList *pEList){
+  int i, j;
+  if( pOrderBy==0 ) return;
+  for(i=0; i<pOrderBy->nExpr; i++){
+    int t = pOrderBy->a[i].u.x.iOrderByCol;
+    if( t==0 ) continue;
+    for(j=0; j<pEList->nExpr; j++){
+      if( pEList->a[j].u.x.iOrderByCol==t ){
+        pOrderBy->a[i].u.x.iOrderByCol = j+1;
+        break;
+      }
+    }
+    if( j>=pEList->nExpr ){
+      pOrderBy->a[i].u.x.iOrderByCol = 0;
+    }
+  }
+}
+
+
+/*
+** pX is an expression of the form:  (vector) IN (SELECT ...)
+** In other words, it is a vector IN operator with a SELECT clause on the
+** LHS.  But not all terms in the vector are indexable and the terms might
+** not be in the correct order for indexing.
+**
+** This routine makes a copy of the input pX expression and then adjusts
+** the vector on the LHS with corresponding changes to the SELECT so that
+** the vector contains only index terms and those terms are in the correct
+** order.  The modified IN expression is returned.  The caller is responsible
+** for deleting the returned expression.
+**
+** Example:
+**
+**    CREATE TABLE t1(a,b,c,d,e,f);
+**    CREATE INDEX t1x1 ON t1(e,c);
+**    SELECT * FROM t1 WHERE (a,b,c,d,e) IN (SELECT v,w,x,y,z FROM t2)
+**                           \_______________________________________/
+**                                     The pX expression
+**
+** Since only columns e and c can be used with the index, in that order,
+** the modified IN expression that is returned will be:
+**
+**        (e,c) IN (SELECT z,x FROM t2)
+**
+** The reduced pX is different from the original (obviously) and thus is
+** only used for indexing, to improve performance.  The original unaltered
+** IN expression must also be run on each output row for correctness.
+*/
+static Expr *removeUnindexableInClauseTerms(
+  Parse *pParse,        /* The parsing context */
+  int iEq,              /* Look at loop terms starting here */
+  WhereLoop *pLoop,     /* The current loop */
+  Expr *pX              /* The IN expression to be reduced */
+){
+  sqlite3 *db = pParse->db;
+  Select *pSelect;            /* Pointer to the SELECT on the RHS */
+  Expr *pNew;
+  pNew = sqlite3ExprDup(db, pX, 0);
+  if( db->mallocFailed==0 ){
+    for(pSelect=pNew->x.pSelect; pSelect; pSelect=pSelect->pPrior){
+      ExprList *pOrigRhs;         /* Original unmodified RHS */
+      ExprList *pOrigLhs = 0;     /* Original unmodified LHS */
+      ExprList *pRhs = 0;         /* New RHS after modifications */
+      ExprList *pLhs = 0;         /* New LHS after mods */
+      int i;                      /* Loop counter */
+
+      assert( ExprUseXSelect(pNew) );
+      pOrigRhs = pSelect->pEList;
+      assert( pNew->pLeft!=0 );
+      assert( ExprUseXList(pNew->pLeft) );
+      if( pSelect==pNew->x.pSelect ){
+        pOrigLhs = pNew->pLeft->x.pList;
+      }
+      for(i=iEq; i<pLoop->nLTerm; i++){
+        if( pLoop->aLTerm[i]->pExpr==pX ){
+          int iField;
+          assert( (pLoop->aLTerm[i]->eOperator & (WO_OR|WO_AND))==0 );
+          iField = pLoop->aLTerm[i]->u.x.iField - 1;
+          if( pOrigRhs->a[iField].pExpr==0 ) continue; /* Duplicate PK column */
+          pRhs = sqlite3ExprListAppend(pParse, pRhs, pOrigRhs->a[iField].pExpr);
+          pOrigRhs->a[iField].pExpr = 0;
+          if( pRhs ) pRhs->a[pRhs->nExpr-1].u.x.iOrderByCol = iField+1;
+          if( pOrigLhs ){
+            assert( pOrigLhs->a[iField].pExpr!=0 );
+            pLhs = sqlite3ExprListAppend(pParse,pLhs,pOrigLhs->a[iField].pExpr);
+            pOrigLhs->a[iField].pExpr = 0;
+          }
+        }
+      }
+      sqlite3ExprListDelete(db, pOrigRhs);
+      if( pOrigLhs ){
+        sqlite3ExprListDelete(db, pOrigLhs);
+        pNew->pLeft->x.pList = pLhs;
+      }
+      pSelect->pEList = pRhs;
+      pSelect->selId = ++pParse->nSelect; /* Req'd for SubrtnSig validity */
+      if( pLhs && pLhs->nExpr==1 ){
+        /* Take care here not to generate a TK_VECTOR containing only a
+        ** single value. Since the parser never creates such a vector, some
+        ** of the subroutines do not handle this case.  */
+        Expr *p = pLhs->a[0].pExpr;
+        pLhs->a[0].pExpr = 0;
+        sqlite3ExprDelete(db, pNew->pLeft);
+        pNew->pLeft = p;
+      }
+
+      /* If either the ORDER BY clause or the GROUP BY clause contains
+      ** references to result-set columns, those references might now be
+      ** obsolete.  So fix them up.
+      */
+      assert( pRhs!=0 || db->mallocFailed );
+      if( pRhs ){
+        adjustOrderByCol(pSelect->pOrderBy, pRhs);
+        adjustOrderByCol(pSelect->pGroupBy, pRhs);
+        for(i=0; i<pRhs->nExpr; i++) pRhs->a[i].u.x.iOrderByCol = 0;
+      }
+
+#if 0
+      printf("For indexing, change the IN expr:\n");
+      sqlite3TreeViewExpr(0, pX, 0);
+      printf("Into:\n");
+      sqlite3TreeViewExpr(0, pNew, 0);
+#endif
+    }
+  }
+  return pNew;
+}
+
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code for a single X IN (....) term of the WHERE clause.
+**
+** This is a special-case of codeEqualityTerm() that works for IN operators
+** only.  It is broken out into a subroutine because this case is
+** uncommon and by splitting it off into a subroutine, the common case
+** runs faster.
+**
+** The current value for the constraint is left in  register iTarget.
+** This routine sets up a loop that will iterate over all values of X.
+*/
+static SQLITE_NOINLINE void codeINTerm(
+  Parse *pParse,      /* The parsing context */
+  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
+  WhereLevel *pLevel, /* The level of the FROM clause we are working on */
+  int iEq,            /* Index of the equality term within this level */
+  int bRev,           /* True for reverse-order IN operations */
+  int iTarget         /* Attempt to leave results in this register */
+){
+  Expr *pX = pTerm->pExpr;
+  int eType = IN_INDEX_NOOP;
+  int iTab;
+  struct InLoop *pIn;
+  WhereLoop *pLoop = pLevel->pWLoop;
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  int nEq = 0;
+  int *aiMap = 0;
+
+  if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0
+    && pLoop->u.btree.pIndex!=0
+    && pLoop->u.btree.pIndex->aSortOrder[iEq]
+  ){
+    testcase( iEq==0 );
+    testcase( bRev );
+    bRev = !bRev;
+  }
+  assert( pX->op==TK_IN );
+
+  for(i=0; i<iEq; i++){
+    if( pLoop->aLTerm[i] && pLoop->aLTerm[i]->pExpr==pX ){
+      disableTerm(pLevel, pTerm);
+      return;
+    }
+  }
+  for(i=iEq;i<pLoop->nLTerm; i++){
+    assert( pLoop->aLTerm[i]!=0 );
+    if( pLoop->aLTerm[i]->pExpr==pX ) nEq++;
+  }
+
+  iTab = 0;
+  if( !ExprUseXSelect(pX) || pX->x.pSelect->pEList->nExpr==1 ){
+    eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, 0, &iTab);
+  }else{
+    Expr *pExpr = pTerm->pExpr;
+    if( pExpr->iTable==0 || !ExprHasProperty(pExpr, EP_Subrtn) ){
+      sqlite3 *db = pParse->db;
+      pX = removeUnindexableInClauseTerms(pParse, iEq, pLoop, pX);
+      if( !db->mallocFailed ){
+        aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*nEq);
+        eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap,&iTab);
+        pExpr->iTable = iTab;
+      }
+      sqlite3ExprDelete(db, pX);
+    }else{
+      int n = sqlite3ExprVectorSize(pX->pLeft);
+      aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*MAX(nEq,n));
+      eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap, &iTab);
+    }
+    pX = pExpr;
+  }
+
+  if( eType==IN_INDEX_INDEX_DESC ){
+    testcase( bRev );
+    bRev = !bRev;
+  }
+  sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iTab, 0);
+  VdbeCoverageIf(v, bRev);
+  VdbeCoverageIf(v, !bRev);
+
+  assert( (pLoop->wsFlags & WHERE_MULTI_OR)==0 );
+  pLoop->wsFlags |= WHERE_IN_ABLE;
+  if( pLevel->u.in.nIn==0 ){
+    pLevel->addrNxt = sqlite3VdbeMakeLabel(pParse);
+  }
+  if( iEq>0 && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0 ){
+    pLoop->wsFlags |= WHERE_IN_EARLYOUT;
+  }
+
+  i = pLevel->u.in.nIn;
+  pLevel->u.in.nIn += nEq;
+  pLevel->u.in.aInLoop =
+     sqlite3WhereRealloc(pTerm->pWC->pWInfo,
+                         pLevel->u.in.aInLoop,
+                         sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn);
+  pIn = pLevel->u.in.aInLoop;
+  if( pIn ){
+    int iMap = 0;               /* Index in aiMap[] */
+    pIn += i;
+    for(i=iEq;i<pLoop->nLTerm; i++){
+      if( pLoop->aLTerm[i]->pExpr==pX ){
+        int iOut = iTarget + i - iEq;
+        if( eType==IN_INDEX_ROWID ){
+          pIn->addrInTop = sqlite3VdbeAddOp2(v, OP_Rowid, iTab, iOut);
+        }else{
+          int iCol = aiMap ? aiMap[iMap++] : 0;
+          pIn->addrInTop = sqlite3VdbeAddOp3(v,OP_Column,iTab, iCol, iOut);
+        }
+        sqlite3VdbeAddOp1(v, OP_IsNull, iOut); VdbeCoverage(v);
+        if( i==iEq ){
+          pIn->iCur = iTab;
+          pIn->eEndLoopOp = bRev ? OP_Prev : OP_Next;
+          if( iEq>0 ){
+            pIn->iBase = iTarget - i;
+            pIn->nPrefix = i;
+          }else{
+            pIn->nPrefix = 0;
+          }
+        }else{
+          pIn->eEndLoopOp = OP_Noop;
+        }
+        pIn++;
+      }
+    }
+    testcase( iEq>0
+              && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0
+              && (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 );
+    if( iEq>0
+     && (pLoop->wsFlags & (WHERE_IN_SEEKSCAN|WHERE_VIRTUALTABLE))==0
+    ){
+      sqlite3VdbeAddOp3(v, OP_SeekHit, pLevel->iIdxCur, 0, iEq);
+    }
+  }else{
+    pLevel->u.in.nIn = 0;
+  }
+  sqlite3DbFree(pParse->db, aiMap);
+}
+#endif
+
+
+/*
+** Generate code for a single equality term of the WHERE clause.  An equality
+** term can be either X=expr or X IN (...).   pTerm is the term to be
+** coded.
+**
+** The current value for the constraint is left in a register, the index
+** of which is returned.  An attempt is made store the result in iTarget but
+** this is only guaranteed for TK_ISNULL and TK_IN constraints.  If the
+** constraint is a TK_EQ or TK_IS, then the current value might be left in
+** some other register and it is the caller's responsibility to compensate.
+**
+** For a constraint of the form X=expr, the expression is evaluated in
+** straight-line code.  For constraints of the form X IN (...)
+** this routine sets up a loop that will iterate over all values of X.
+*/
+static int codeEqualityTerm(
+  Parse *pParse,      /* The parsing context */
+  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
+  WhereLevel *pLevel, /* The level of the FROM clause we are working on */
+  int iEq,            /* Index of the equality term within this level */
+  int bRev,           /* True for reverse-order IN operations */
+  int iTarget         /* Attempt to leave results in this register */
+){
+  Expr *pX = pTerm->pExpr;
+  int iReg;                  /* Register holding results */
+
+  assert( pLevel->pWLoop->aLTerm[iEq]==pTerm );
+  assert( iTarget>0 );
+  if( pX->op==TK_EQ || pX->op==TK_IS ){
+    iReg = sqlite3ExprCodeTarget(pParse, pX->pRight, iTarget);
+  }else if( pX->op==TK_ISNULL ){
+    iReg = iTarget;
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_Null, 0, iReg);
+#ifndef SQLITE_OMIT_SUBQUERY
+  }else{
+    assert( pX->op==TK_IN );
+    iReg = iTarget;
+    codeINTerm(pParse, pTerm, pLevel, iEq, bRev, iTarget);
+#endif
+  }
+
+  /* As an optimization, try to disable the WHERE clause term that is
+  ** driving the index as it will always be true.  The correct answer is
+  ** obtained regardless, but we might get the answer with fewer CPU cycles
+  ** by omitting the term.
+  **
+  ** But do not disable the term unless we are certain that the term is
+  ** not a transitive constraint.  For an example of where that does not
+  ** work, see https://sqlite.org/forum/forumpost/eb8613976a (2021-05-04)
+  */
+  if( (pLevel->pWLoop->wsFlags & WHERE_TRANSCONS)==0
+   || (pTerm->eOperator & WO_EQUIV)==0
+  ){
+    disableTerm(pLevel, pTerm);
+  }
+
+  return iReg;
+}
+
+/*
+** Generate code that will evaluate all == and IN constraints for an
+** index scan.
+**
+** For example, consider table t1(a,b,c,d,e,f) with index i1(a,b,c).
+** Suppose the WHERE clause is this:  a==5 AND b IN (1,2,3) AND c>5 AND c<10
+** The index has as many as three equality constraints, but in this
+** example, the third "c" value is an inequality.  So only two
+** constraints are coded.  This routine will generate code to evaluate
+** a==5 and b IN (1,2,3).  The current values for a and b will be stored
+** in consecutive registers and the index of the first register is returned.
+**
+** In the example above nEq==2.  But this subroutine works for any value
+** of nEq including 0.  If nEq==0, this routine is nearly a no-op.
+** The only thing it does is allocate the pLevel->iMem memory cell and
+** compute the affinity string.
+**
+** The nExtraReg parameter is 0 or 1.  It is 0 if all WHERE clause constraints
+** are == or IN and are covered by the nEq.  nExtraReg is 1 if there is
+** an inequality constraint (such as the "c>=5 AND c<10" in the example) that
+** occurs after the nEq quality constraints.
+**
+** This routine allocates a range of nEq+nExtraReg memory cells and returns
+** the index of the first memory cell in that range. The code that
+** calls this routine will use that memory range to store keys for
+** start and termination conditions of the loop.
+** key value of the loop.  If one or more IN operators appear, then
+** this routine allocates an additional nEq memory cells for internal
+** use.
+**
+** Before returning, *pzAff is set to point to a buffer containing a
+** copy of the column affinity string of the index allocated using
+** sqlite3DbMalloc(). Except, entries in the copy of the string associated
+** with equality constraints that use BLOB or NONE affinity are set to
+** SQLITE_AFF_BLOB. This is to deal with SQL such as the following:
+**
+**   CREATE TABLE t1(a TEXT PRIMARY KEY, b);
+**   SELECT ... FROM t1 AS t2, t1 WHERE t1.a = t2.b;
+**
+** In the example above, the index on t1(a) has TEXT affinity. But since
+** the right hand side of the equality constraint (t2.b) has BLOB/NONE affinity,
+** no conversion should be attempted before using a t2.b value as part of
+** a key to search the index. Hence the first byte in the returned affinity
+** string in this example would be set to SQLITE_AFF_BLOB.
+*/
+static int codeAllEqualityTerms(
+  Parse *pParse,        /* Parsing context */
+  WhereLevel *pLevel,   /* Which nested loop of the FROM we are coding */
+  int bRev,             /* Reverse the order of IN operators */
+  int nExtraReg,        /* Number of extra registers to allocate */
+  char **pzAff          /* OUT: Set to point to affinity string */
+){
+  u16 nEq;                      /* The number of == or IN constraints to code */
+  u16 nSkip;                    /* Number of left-most columns to skip */
+  Vdbe *v = pParse->pVdbe;      /* The vm under construction */
+  Index *pIdx;                  /* The index being used for this loop */
+  WhereTerm *pTerm;             /* A single constraint term */
+  WhereLoop *pLoop;             /* The WhereLoop object */
+  int j;                        /* Loop counter */
+  int regBase;                  /* Base register */
+  int nReg;                     /* Number of registers to allocate */
+  char *zAff;                   /* Affinity string to return */
+
+  /* This module is only called on query plans that use an index. */
+  pLoop = pLevel->pWLoop;
+  assert( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 );
+  nEq = pLoop->u.btree.nEq;
+  nSkip = pLoop->nSkip;
+  pIdx = pLoop->u.btree.pIndex;
+  assert( pIdx!=0 );
+
+  /* Figure out how many memory cells we will need then allocate them.
+  */
+  regBase = pParse->nMem + 1;
+  nReg = nEq + nExtraReg;
+  pParse->nMem += nReg;
+
+  zAff = sqlite3DbStrDup(pParse->db,sqlite3IndexAffinityStr(pParse->db,pIdx));
+  assert( zAff!=0 || pParse->db->mallocFailed );
+
+  if( nSkip ){
+    int iIdxCur = pLevel->iIdxCur;
+    sqlite3VdbeAddOp3(v, OP_Null, 0, regBase, regBase+nSkip-1);
+    sqlite3VdbeAddOp1(v, (bRev?OP_Last:OP_Rewind), iIdxCur);
+    VdbeCoverageIf(v, bRev==0);
+    VdbeCoverageIf(v, bRev!=0);
+    VdbeComment((v, "begin skip-scan on %s", pIdx->zName));
+    j = sqlite3VdbeAddOp0(v, OP_Goto);
+    assert( pLevel->addrSkip==0 );
+    pLevel->addrSkip = sqlite3VdbeAddOp4Int(v, (bRev?OP_SeekLT:OP_SeekGT),
+                            iIdxCur, 0, regBase, nSkip);
+    VdbeCoverageIf(v, bRev==0);
+    VdbeCoverageIf(v, bRev!=0);
+    sqlite3VdbeJumpHere(v, j);
+    for(j=0; j<nSkip; j++){
+      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, j, regBase+j);
+      testcase( pIdx->aiColumn[j]==XN_EXPR );
+      VdbeComment((v, "%s", explainIndexColumnName(pIdx, j)));
+    }
+  }
+
+  /* Evaluate the equality constraints
+  */
+  assert( zAff==0 || (int)strlen(zAff)>=nEq );
+  for(j=nSkip; j<nEq; j++){
+    int r1;
+    pTerm = pLoop->aLTerm[j];
+    assert( pTerm!=0 );
+    /* The following testcase is true for indices with redundant columns.
+    ** Ex: CREATE INDEX i1 ON t1(a,b,a); SELECT * FROM t1 WHERE a=0 AND b=0; */
+    testcase( (pTerm->wtFlags & TERM_CODED)!=0 );
+    testcase( pTerm->wtFlags & TERM_VIRTUAL );
+    r1 = codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, regBase+j);
+    if( r1!=regBase+j ){
+      if( nReg==1 ){
+        sqlite3ReleaseTempReg(pParse, regBase);
+        regBase = r1;
+      }else{
+        sqlite3VdbeAddOp2(v, OP_Copy, r1, regBase+j);
+      }
+    }
+    if( pTerm->eOperator & WO_IN ){
+      if( pTerm->pExpr->flags & EP_xIsSelect ){
+        /* No affinity ever needs to be (or should be) applied to a value
+        ** from the RHS of an "? IN (SELECT ...)" expression. The
+        ** sqlite3FindInIndex() routine has already ensured that the
+        ** affinity of the comparison has been applied to the value.  */
+        if( zAff ) zAff[j] = SQLITE_AFF_BLOB;
+      }
+    }else if( (pTerm->eOperator & WO_ISNULL)==0 ){
+      Expr *pRight = pTerm->pExpr->pRight;
+      if( (pTerm->wtFlags & TERM_IS)==0 && sqlite3ExprCanBeNull(pRight) ){
+        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+j, pLevel->addrBrk);
+        VdbeCoverage(v);
+      }
+      if( pParse->nErr==0 ){
+        assert( pParse->db->mallocFailed==0 );
+        if( sqlite3CompareAffinity(pRight, zAff[j])==SQLITE_AFF_BLOB ){
+          zAff[j] = SQLITE_AFF_BLOB;
+        }
+        if( sqlite3ExprNeedsNoAffinityChange(pRight, zAff[j]) ){
+          zAff[j] = SQLITE_AFF_BLOB;
+        }
+      }
+    }
+  }
+  *pzAff = zAff;
+  return regBase;
+}
+
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+/*
+** If the most recently coded instruction is a constant range constraint
+** (a string literal) that originated from the LIKE optimization, then
+** set P3 and P5 on the OP_String opcode so that the string will be cast
+** to a BLOB at appropriate times.
+**
+** The LIKE optimization trys to evaluate "x LIKE 'abc%'" as a range
+** expression: "x>='ABC' AND x<'abd'".  But this requires that the range
+** scan loop run twice, once for strings and a second time for BLOBs.
+** The OP_String opcodes on the second pass convert the upper and lower
+** bound string constants to blobs.  This routine makes the necessary changes
+** to the OP_String opcodes for that to happen.
+**
+** Except, of course, if SQLITE_LIKE_DOESNT_MATCH_BLOBS is defined, then
+** only the one pass through the string space is required, so this routine
+** becomes a no-op.
+*/
+static void whereLikeOptimizationStringFixup(
+  Vdbe *v,                /* prepared statement under construction */
+  WhereLevel *pLevel,     /* The loop that contains the LIKE operator */
+  WhereTerm *pTerm        /* The upper or lower bound just coded */
+){
+  if( pTerm->wtFlags & TERM_LIKEOPT ){
+    VdbeOp *pOp;
+    assert( pLevel->iLikeRepCntr>0 );
+    pOp = sqlite3VdbeGetLastOp(v);
+    assert( pOp!=0 );
+    assert( pOp->opcode==OP_String8
+            || pTerm->pWC->pWInfo->pParse->db->mallocFailed );
+    pOp->p3 = (int)(pLevel->iLikeRepCntr>>1);  /* Register holding counter */
+    pOp->p5 = (u8)(pLevel->iLikeRepCntr&1);    /* ASC or DESC */
+  }
+}
+#else
+# define whereLikeOptimizationStringFixup(A,B,C)
+#endif
+
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/*
+** Information is passed from codeCursorHint() down to individual nodes of
+** the expression tree (by sqlite3WalkExpr()) using an instance of this
+** structure.
+*/
+struct CCurHint {
+  int iTabCur;    /* Cursor for the main table */
+  int iIdxCur;    /* Cursor for the index, if pIdx!=0.  Unused otherwise */
+  Index *pIdx;    /* The index used to access the table */
+};
+
+/*
+** This function is called for every node of an expression that is a candidate
+** for a cursor hint on an index cursor.  For TK_COLUMN nodes that reference
+** the table CCurHint.iTabCur, verify that the same column can be
+** accessed through the index.  If it cannot, then set pWalker->eCode to 1.
+*/
+static int codeCursorHintCheckExpr(Walker *pWalker, Expr *pExpr){
+  struct CCurHint *pHint = pWalker->u.pCCurHint;
+  assert( pHint->pIdx!=0 );
+  if( pExpr->op==TK_COLUMN
+   && pExpr->iTable==pHint->iTabCur
+   && sqlite3TableColumnToIndex(pHint->pIdx, pExpr->iColumn)<0
+  ){
+    pWalker->eCode = 1;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Test whether or not expression pExpr, which was part of a WHERE clause,
+** should be included in the cursor-hint for a table that is on the rhs
+** of a LEFT JOIN. Set Walker.eCode to non-zero before returning if the
+** expression is not suitable.
+**
+** An expression is unsuitable if it might evaluate to non NULL even if
+** a TK_COLUMN node that does affect the value of the expression is set
+** to NULL. For example:
+**
+**   col IS NULL
+**   col IS NOT NULL
+**   coalesce(col, 1)
+**   CASE WHEN col THEN 0 ELSE 1 END
+*/
+static int codeCursorHintIsOrFunction(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_IS
+   || pExpr->op==TK_ISNULL || pExpr->op==TK_ISNOT
+   || pExpr->op==TK_NOTNULL || pExpr->op==TK_CASE
+  ){
+    pWalker->eCode = 1;
+  }else if( pExpr->op==TK_FUNCTION ){
+    int d1;
+    char d2[4];
+    if( 0==sqlite3IsLikeFunction(pWalker->pParse->db, pExpr, &d1, d2) ){
+      pWalker->eCode = 1;
+    }
+  }
+
+  return WRC_Continue;
+}
+
+
+/*
+** This function is called on every node of an expression tree used as an
+** argument to the OP_CursorHint instruction. If the node is a TK_COLUMN
+** that accesses any table other than the one identified by
+** CCurHint.iTabCur, then do the following:
+**
+**   1) allocate a register and code an OP_Column instruction to read
+**      the specified column into the new register, and
+**
+**   2) transform the expression node to a TK_REGISTER node that reads
+**      from the newly populated register.
+**
+** Also, if the node is a TK_COLUMN that does access the table identified
+** by pCCurHint.iTabCur, and an index is being used (which we will
+** know because CCurHint.pIdx!=0) then transform the TK_COLUMN into
+** an access of the index rather than the original table.
+*/
+static int codeCursorHintFixExpr(Walker *pWalker, Expr *pExpr){
+  int rc = WRC_Continue;
+  int reg;
+  struct CCurHint *pHint = pWalker->u.pCCurHint;
+  if( pExpr->op==TK_COLUMN ){
+    if( pExpr->iTable!=pHint->iTabCur ){
+      reg = ++pWalker->pParse->nMem;   /* Register for column value */
+      reg = sqlite3ExprCodeTarget(pWalker->pParse, pExpr, reg);
+      pExpr->op = TK_REGISTER;
+      pExpr->iTable = reg;
+    }else if( pHint->pIdx!=0 ){
+      pExpr->iTable = pHint->iIdxCur;
+      pExpr->iColumn = sqlite3TableColumnToIndex(pHint->pIdx, pExpr->iColumn);
+      assert( pExpr->iColumn>=0 );
+    }
+  }else if( pExpr->pAggInfo ){
+    rc = WRC_Prune;
+    reg = ++pWalker->pParse->nMem;   /* Register for column value */
+    reg = sqlite3ExprCodeTarget(pWalker->pParse, pExpr, reg);
+    pExpr->op = TK_REGISTER;
+    pExpr->iTable = reg;
+  }else if( pExpr->op==TK_TRUEFALSE ){
+    /* Do not walk disabled expressions.  tag-20230504-1 */
+    return WRC_Prune;
+  }
+  return rc;
+}
+
+/*
+** Insert an OP_CursorHint instruction if it is appropriate to do so.
+*/
+static void codeCursorHint(
+  SrcItem *pTabItem,  /* FROM clause item */
+  WhereInfo *pWInfo,    /* The where clause */
+  WhereLevel *pLevel,   /* Which loop to provide hints for */
+  WhereTerm *pEndRange  /* Hint this end-of-scan boundary term if not NULL */
+){
+  Parse *pParse = pWInfo->pParse;
+  sqlite3 *db = pParse->db;
+  Vdbe *v = pParse->pVdbe;
+  Expr *pExpr = 0;
+  WhereLoop *pLoop = pLevel->pWLoop;
+  int iCur;
+  WhereClause *pWC;
+  WhereTerm *pTerm;
+  int i, j;
+  struct CCurHint sHint;
+  Walker sWalker;
+
+  if( OptimizationDisabled(db, SQLITE_CursorHints) ) return;
+  iCur = pLevel->iTabCur;
+  assert( iCur==pWInfo->pTabList->a[pLevel->iFrom].iCursor );
+  sHint.iTabCur = iCur;
+  sHint.iIdxCur = pLevel->iIdxCur;
+  sHint.pIdx = pLoop->u.btree.pIndex;
+  memset(&sWalker, 0, sizeof(sWalker));
+  sWalker.pParse = pParse;
+  sWalker.u.pCCurHint = &sHint;
+  pWC = &pWInfo->sWC;
+  for(i=0; i<pWC->nBase; i++){
+    pTerm = &pWC->a[i];
+    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+    if( pTerm->prereqAll & pLevel->notReady ) continue;
+
+    /* Any terms specified as part of the ON(...) clause for any LEFT
+    ** JOIN for which the current table is not the rhs are omitted
+    ** from the cursor-hint.
+    **
+    ** If this table is the rhs of a LEFT JOIN, "IS" or "IS NULL" terms
+    ** that were specified as part of the WHERE clause must be excluded.
+    ** This is to address the following:
+    **
+    **   SELECT ... t1 LEFT JOIN t2 ON (t1.a=t2.b) WHERE t2.c IS NULL;
+    **
+    ** Say there is a single row in t2 that matches (t1.a=t2.b), but its
+    ** t2.c values is not NULL. If the (t2.c IS NULL) constraint is
+    ** pushed down to the cursor, this row is filtered out, causing
+    ** SQLite to synthesize a row of NULL values. Which does match the
+    ** WHERE clause, and so the query returns a row. Which is incorrect.
+    **
+    ** For the same reason, WHERE terms such as:
+    **
+    **   WHERE 1 = (t2.c IS NULL)
+    **
+    ** are also excluded. See codeCursorHintIsOrFunction() for details.
+    */
+    if( pTabItem->fg.jointype & JT_LEFT ){
+      Expr *pExpr = pTerm->pExpr;
+      if( !ExprHasProperty(pExpr, EP_OuterON)
+       || pExpr->w.iJoin!=pTabItem->iCursor
+      ){
+        sWalker.eCode = 0;
+        sWalker.xExprCallback = codeCursorHintIsOrFunction;
+        sqlite3WalkExpr(&sWalker, pTerm->pExpr);
+        if( sWalker.eCode ) continue;
+      }
+    }else{
+      if( ExprHasProperty(pTerm->pExpr, EP_OuterON) ) continue;
+    }
+
+    /* All terms in pWLoop->aLTerm[] except pEndRange are used to initialize
+    ** the cursor.  These terms are not needed as hints for a pure range
+    ** scan (that has no == terms) so omit them. */
+    if( pLoop->u.btree.nEq==0 && pTerm!=pEndRange ){
+      for(j=0; j<pLoop->nLTerm && pLoop->aLTerm[j]!=pTerm; j++){}
+      if( j<pLoop->nLTerm ) continue;
+    }
+
+    /* No subqueries or non-deterministic functions allowed */
+    if( sqlite3ExprContainsSubquery(pTerm->pExpr) ) continue;
+
+    /* For an index scan, make sure referenced columns are actually in
+    ** the index. */
+    if( sHint.pIdx!=0 ){
+      sWalker.eCode = 0;
+      sWalker.xExprCallback = codeCursorHintCheckExpr;
+      sqlite3WalkExpr(&sWalker, pTerm->pExpr);
+      if( sWalker.eCode ) continue;
+    }
+
+    /* If we survive all prior tests, that means this term is worth hinting */
+    pExpr = sqlite3ExprAnd(pParse, pExpr, sqlite3ExprDup(db, pTerm->pExpr, 0));
+  }
+  if( pExpr!=0 ){
+    sWalker.xExprCallback = codeCursorHintFixExpr;
+    if( pParse->nErr==0 ) sqlite3WalkExpr(&sWalker, pExpr);
+    sqlite3VdbeAddOp4(v, OP_CursorHint,
+                      (sHint.pIdx ? sHint.iIdxCur : sHint.iTabCur), 0, 0,
+                      (const char*)pExpr, P4_EXPR);
+  }
+}
+#else
+# define codeCursorHint(A,B,C,D)  /* No-op */
+#endif /* SQLITE_ENABLE_CURSOR_HINTS */
+
+/*
+** Cursor iCur is open on an intkey b-tree (a table). Register iRowid contains
+** a rowid value just read from cursor iIdxCur, open on index pIdx. This
+** function generates code to do a deferred seek of cursor iCur to the
+** rowid stored in register iRowid.
+**
+** Normally, this is just:
+**
+**   OP_DeferredSeek $iCur $iRowid
+**
+** Which causes a seek on $iCur to the row with rowid $iRowid.
+**
+** However, if the scan currently being coded is a branch of an OR-loop and
+** the statement currently being coded is a SELECT, then additional information
+** is added that might allow OP_Column to omit the seek and instead do its
+** lookup on the index, thus avoiding an expensive seek operation.  To
+** enable this optimization, the P3 of OP_DeferredSeek is set to iIdxCur
+** and P4 is set to an array of integers containing one entry for each column
+** in the table.  For each table column, if the column is the i'th
+** column of the index, then the corresponding array entry is set to (i+1).
+** If the column does not appear in the index at all, the array entry is set
+** to 0.  The OP_Column opcode can check this array to see if the column it
+** wants is in the index and if it is, it will substitute the index cursor
+** and column number and continue with those new values, rather than seeking
+** the table cursor.
+*/
+static void codeDeferredSeek(
+  WhereInfo *pWInfo,              /* Where clause context */
+  Index *pIdx,                    /* Index scan is using */
+  int iCur,                       /* Cursor for IPK b-tree */
+  int iIdxCur                     /* Index cursor */
+){
+  Parse *pParse = pWInfo->pParse; /* Parse context */
+  Vdbe *v = pParse->pVdbe;        /* Vdbe to generate code within */
+
+  assert( iIdxCur>0 );
+  assert( pIdx->aiColumn[pIdx->nColumn-1]==-1 );
+
+  pWInfo->bDeferredSeek = 1;
+  sqlite3VdbeAddOp3(v, OP_DeferredSeek, iIdxCur, 0, iCur);
+  if( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))
+   && DbMaskAllZero(sqlite3ParseToplevel(pParse)->writeMask)
+  ){
+    int i;
+    Table *pTab = pIdx->pTable;
+    u32 *ai = (u32*)sqlite3DbMallocZero(pParse->db, sizeof(u32)*(pTab->nCol+1));
+    if( ai ){
+      ai[0] = pTab->nCol;
+      for(i=0; i<pIdx->nColumn-1; i++){
+        int x1, x2;
+        assert( pIdx->aiColumn[i]<pTab->nCol );
+        x1 = pIdx->aiColumn[i];
+        x2 = sqlite3TableColumnToStorage(pTab, x1);
+        testcase( x1!=x2 );
+        if( x1>=0 ) ai[x2+1] = i+1;
+      }
+      sqlite3VdbeChangeP4(v, -1, (char*)ai, P4_INTARRAY);
+    }
+  }
+}
+
+/*
+** If the expression passed as the second argument is a vector, generate
+** code to write the first nReg elements of the vector into an array
+** of registers starting with iReg.
+**
+** If the expression is not a vector, then nReg must be passed 1. In
+** this case, generate code to evaluate the expression and leave the
+** result in register iReg.
+*/
+static void codeExprOrVector(Parse *pParse, Expr *p, int iReg, int nReg){
+  assert( nReg>0 );
+  if( p && sqlite3ExprIsVector(p) ){
+#ifndef SQLITE_OMIT_SUBQUERY
+    if( ExprUseXSelect(p) ){
+      Vdbe *v = pParse->pVdbe;
+      int iSelect;
+      assert( p->op==TK_SELECT );
+      iSelect = sqlite3CodeSubselect(pParse, p);
+      sqlite3VdbeAddOp3(v, OP_Copy, iSelect, iReg, nReg-1);
+    }else
+#endif
+    {
+      int i;
+      const ExprList *pList;
+      assert( ExprUseXList(p) );
+      pList = p->x.pList;
+      assert( nReg<=pList->nExpr );
+      for(i=0; i<nReg; i++){
+        sqlite3ExprCode(pParse, pList->a[i].pExpr, iReg+i);
+      }
+    }
+  }else{
+    assert( nReg==1 || pParse->nErr );
+    sqlite3ExprCode(pParse, p, iReg);
+  }
+}
+
+/*
+** The pTruth expression is always true because it is the WHERE clause
+** a partial index that is driving a query loop.  Look through all of the
+** WHERE clause terms on the query, and if any of those terms must be
+** true because pTruth is true, then mark those WHERE clause terms as
+** coded.
+*/
+static void whereApplyPartialIndexConstraints(
+  Expr *pTruth,
+  int iTabCur,
+  WhereClause *pWC
+){
+  int i;
+  WhereTerm *pTerm;
+  while( pTruth->op==TK_AND ){
+    whereApplyPartialIndexConstraints(pTruth->pLeft, iTabCur, pWC);
+    pTruth = pTruth->pRight;
+  }
+  for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+    Expr *pExpr;
+    if( pTerm->wtFlags & TERM_CODED ) continue;
+    pExpr = pTerm->pExpr;
+    if( sqlite3ExprCompare(0, pExpr, pTruth, iTabCur)==0 ){
+      pTerm->wtFlags |= TERM_CODED;
+    }
+  }
+}
+
+/*
+** This routine is called right after An OP_Filter has been generated and
+** before the corresponding index search has been performed.  This routine
+** checks to see if there are additional Bloom filters in inner loops that
+** can be checked prior to doing the index lookup.  If there are available
+** inner-loop Bloom filters, then evaluate those filters now, before the
+** index lookup.  The idea is that a Bloom filter check is way faster than
+** an index lookup, and the Bloom filter might return false, meaning that
+** the index lookup can be skipped.
+**
+** We know that an inner loop uses a Bloom filter because it has the
+** WhereLevel.regFilter set.  If an inner-loop Bloom filter is checked,
+** then clear the WhereLevel.regFilter value to prevent the Bloom filter
+** from being checked a second time when the inner loop is evaluated.
+*/
+static SQLITE_NOINLINE void filterPullDown(
+  Parse *pParse,       /* Parsing context */
+  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
+  int iLevel,          /* Which level of pWInfo->a[] should be coded */
+  int addrNxt,         /* Jump here to bypass inner loops */
+  Bitmask notReady     /* Loops that are not ready */
+){
+  while( ++iLevel < pWInfo->nLevel ){
+    WhereLevel *pLevel = &pWInfo->a[iLevel];
+    WhereLoop *pLoop = pLevel->pWLoop;
+    if( pLevel->regFilter==0 ) continue;
+    if( pLevel->pWLoop->nSkip ) continue;
+    /*         ,--- Because sqlite3ConstructBloomFilter() has will not have set
+    **  vvvvv--'    pLevel->regFilter if this were true. */
+    if( NEVER(pLoop->prereq & notReady) ) continue;
+    assert( pLevel->addrBrk==0 );
+    pLevel->addrBrk = addrNxt;
+    if( pLoop->wsFlags & WHERE_IPK ){
+      WhereTerm *pTerm = pLoop->aLTerm[0];
+      int regRowid;
+      assert( pTerm!=0 );
+      assert( pTerm->pExpr!=0 );
+      testcase( pTerm->wtFlags & TERM_VIRTUAL );
+      regRowid = sqlite3GetTempReg(pParse);
+      regRowid = codeEqualityTerm(pParse, pTerm, pLevel, 0, 0, regRowid);
+      sqlite3VdbeAddOp2(pParse->pVdbe, OP_MustBeInt, regRowid, addrNxt);
+      VdbeCoverage(pParse->pVdbe);
+      sqlite3VdbeAddOp4Int(pParse->pVdbe, OP_Filter, pLevel->regFilter,
+                           addrNxt, regRowid, 1);
+      VdbeCoverage(pParse->pVdbe);
+    }else{
+      u16 nEq = pLoop->u.btree.nEq;
+      int r1;
+      char *zStartAff;
+
+      assert( pLoop->wsFlags & WHERE_INDEXED );
+      assert( (pLoop->wsFlags & WHERE_COLUMN_IN)==0 );
+      r1 = codeAllEqualityTerms(pParse,pLevel,0,0,&zStartAff);
+      codeApplyAffinity(pParse, r1, nEq, zStartAff);
+      sqlite3DbFree(pParse->db, zStartAff);
+      sqlite3VdbeAddOp4Int(pParse->pVdbe, OP_Filter, pLevel->regFilter,
+                           addrNxt, r1, nEq);
+      VdbeCoverage(pParse->pVdbe);
+    }
+    pLevel->regFilter = 0;
+    pLevel->addrBrk = 0;
+  }
+}
+
+/*
+** Loop pLoop is a WHERE_INDEXED level that uses at least one IN(...)
+** operator. Return true if level pLoop is guaranteed to visit only one
+** row for each key generated for the index.
+*/
+static int whereLoopIsOneRow(WhereLoop *pLoop){
+  if( pLoop->u.btree.pIndex->onError
+   && pLoop->nSkip==0
+   && pLoop->u.btree.nEq==pLoop->u.btree.pIndex->nKeyCol
+  ){
+    int ii;
+    for(ii=0; ii<pLoop->u.btree.nEq; ii++){
+      if( pLoop->aLTerm[ii]->eOperator & (WO_IS|WO_ISNULL) ){
+        return 0;
+      }
+    }
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Generate code for the start of the iLevel-th loop in the WHERE clause
+** implementation described by pWInfo.
+*/
+SQLITE_PRIVATE Bitmask sqlite3WhereCodeOneLoopStart(
+  Parse *pParse,       /* Parsing context */
+  Vdbe *v,             /* Prepared statement under construction */
+  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
+  int iLevel,          /* Which level of pWInfo->a[] should be coded */
+  WhereLevel *pLevel,  /* The current level pointer */
+  Bitmask notReady     /* Which tables are currently available */
+){
+  int j, k;            /* Loop counters */
+  int iCur;            /* The VDBE cursor for the table */
+  int addrNxt;         /* Where to jump to continue with the next IN case */
+  int bRev;            /* True if we need to scan in reverse order */
+  WhereLoop *pLoop;    /* The WhereLoop object being coded */
+  WhereClause *pWC;    /* Decomposition of the entire WHERE clause */
+  WhereTerm *pTerm;               /* A WHERE clause term */
+  sqlite3 *db;                    /* Database connection */
+  SrcItem *pTabItem;              /* FROM clause term being coded */
+  int addrBrk;                    /* Jump here to break out of the loop */
+  int addrHalt;                   /* addrBrk for the outermost loop */
+  int addrCont;                   /* Jump here to continue with next cycle */
+  int iRowidReg = 0;        /* Rowid is stored in this register, if not zero */
+  int iReleaseReg = 0;      /* Temp register to free before returning */
+  Index *pIdx = 0;          /* Index used by loop (if any) */
+  int iLoop;                /* Iteration of constraint generator loop */
+
+  pWC = &pWInfo->sWC;
+  db = pParse->db;
+  pLoop = pLevel->pWLoop;
+  pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
+  iCur = pTabItem->iCursor;
+  pLevel->notReady = notReady & ~sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur);
+  bRev = (pWInfo->revMask>>iLevel)&1;
+  VdbeModuleComment((v, "Begin WHERE-loop%d: %s",
+                     iLevel, pTabItem->pSTab->zName));
+#if WHERETRACE_ENABLED /* 0x4001 */
+  if( sqlite3WhereTrace & 0x1 ){
+    sqlite3DebugPrintf("Coding level %d of %d:  notReady=%llx  iFrom=%d\n",
+       iLevel, pWInfo->nLevel, (u64)notReady, pLevel->iFrom);
+    if( sqlite3WhereTrace & 0x1000 ){
+      sqlite3WhereLoopPrint(pLoop, pWC);
+    }
+  }
+  if( (sqlite3WhereTrace & 0x4001)==0x4001 ){
+    if( iLevel==0 ){
+      sqlite3DebugPrintf("WHERE clause being coded:\n");
+      sqlite3TreeViewExpr(0, pWInfo->pWhere, 0);
+    }
+    sqlite3DebugPrintf("All WHERE-clause terms before coding:\n");
+    sqlite3WhereClausePrint(pWC);
+  }
+#endif
+
+  /* Create labels for the "break" and "continue" instructions
+  ** for the current loop.  Jump to addrBrk to break out of a loop.
+  ** Jump to cont to go immediately to the next iteration of the
+  ** loop.
+  **
+  ** When there is an IN operator, we also have a "addrNxt" label that
+  ** means to continue with the next IN value combination.  When
+  ** there are no IN operators in the constraints, the "addrNxt" label
+  ** is the same as "addrBrk".
+  */
+  addrBrk = pLevel->addrBrk = pLevel->addrNxt = sqlite3VdbeMakeLabel(pParse);
+  addrCont = pLevel->addrCont = sqlite3VdbeMakeLabel(pParse);
+
+  /* If this is the right table of a LEFT OUTER JOIN, allocate and
+  ** initialize a memory cell that records if this table matches any
+  ** row of the left table of the join.
+  */
+  assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))
+       || pLevel->iFrom>0 || (pTabItem[0].fg.jointype & JT_LEFT)==0
+  );
+  if( pLevel->iFrom>0 && (pTabItem[0].fg.jointype & JT_LEFT)!=0 ){
+    pLevel->iLeftJoin = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
+    VdbeComment((v, "init LEFT JOIN match flag"));
+  }
+
+  /* Compute a safe address to jump to if we discover that the table for
+  ** this loop is empty and can never contribute content. */
+  for(j=iLevel; j>0; j--){
+    if( pWInfo->a[j].iLeftJoin ) break;
+    if( pWInfo->a[j].pRJ ) break;
+  }
+  addrHalt = pWInfo->a[j].addrBrk;
+
+  /* Special case of a FROM clause subquery implemented as a co-routine */
+  if( pTabItem->fg.viaCoroutine ){
+    int regYield;
+    Subquery *pSubq;
+    assert( pTabItem->fg.isSubquery && pTabItem->u4.pSubq!=0 );
+    pSubq = pTabItem->u4.pSubq;
+    regYield = pSubq->regReturn;
+    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pSubq->addrFillSub);
+    pLevel->p2 =  sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk);
+    VdbeCoverage(v);
+    VdbeComment((v, "next row of %s", pTabItem->pSTab->zName));
+    pLevel->op = OP_Goto;
+  }else
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if(  (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
+    /* Case 1:  The table is a virtual-table.  Use the VFilter and VNext
+    **          to access the data.
+    */
+    int iReg;   /* P3 Value for OP_VFilter */
+    int addrNotFound;
+    int nConstraint = pLoop->nLTerm;
+
+    iReg = sqlite3GetTempRange(pParse, nConstraint+2);
+    addrNotFound = pLevel->addrBrk;
+    for(j=0; j<nConstraint; j++){
+      int iTarget = iReg+j+2;
+      pTerm = pLoop->aLTerm[j];
+      if( NEVER(pTerm==0) ) continue;
+      if( pTerm->eOperator & WO_IN ){
+        if( SMASKBIT32(j) & pLoop->u.vtab.mHandleIn ){
+          int iTab = pParse->nTab++;
+          int iCache = ++pParse->nMem;
+          sqlite3CodeRhsOfIN(pParse, pTerm->pExpr, iTab);
+          sqlite3VdbeAddOp3(v, OP_VInitIn, iTab, iTarget, iCache);
+        }else{
+          codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, iTarget);
+          addrNotFound = pLevel->addrNxt;
+        }
+      }else{
+        Expr *pRight = pTerm->pExpr->pRight;
+        codeExprOrVector(pParse, pRight, iTarget, 1);
+        if( pTerm->eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET
+         && pLoop->u.vtab.bOmitOffset
+        ){
+          assert( pTerm->eOperator==WO_AUX );
+          assert( pWInfo->pSelect!=0 );
+          assert( pWInfo->pSelect->iOffset>0 );
+          sqlite3VdbeAddOp2(v, OP_Integer, 0, pWInfo->pSelect->iOffset);
+          VdbeComment((v,"Zero OFFSET counter"));
+        }
+      }
+    }
+    sqlite3VdbeAddOp2(v, OP_Integer, pLoop->u.vtab.idxNum, iReg);
+    sqlite3VdbeAddOp2(v, OP_Integer, nConstraint, iReg+1);
+    sqlite3VdbeAddOp4(v, OP_VFilter, iCur, addrNotFound, iReg,
+                      pLoop->u.vtab.idxStr,
+                      pLoop->u.vtab.needFree ? P4_DYNAMIC : P4_STATIC);
+    VdbeCoverage(v);
+    pLoop->u.vtab.needFree = 0;
+    /* An OOM inside of AddOp4(OP_VFilter) instruction above might have freed
+    ** the u.vtab.idxStr.  NULL it out to prevent a use-after-free */
+    if( db->mallocFailed ) pLoop->u.vtab.idxStr = 0;
+    pLevel->p1 = iCur;
+    pLevel->op = pWInfo->eOnePass ? OP_Noop : OP_VNext;
+    pLevel->p2 = sqlite3VdbeCurrentAddr(v);
+    assert( (pLoop->wsFlags & WHERE_MULTI_OR)==0 );
+
+    for(j=0; j<nConstraint; j++){
+      pTerm = pLoop->aLTerm[j];
+      if( j<16 && (pLoop->u.vtab.omitMask>>j)&1 ){
+        disableTerm(pLevel, pTerm);
+        continue;
+      }
+      if( (pTerm->eOperator & WO_IN)!=0
+       && (SMASKBIT32(j) & pLoop->u.vtab.mHandleIn)==0
+       && !db->mallocFailed
+      ){
+        Expr *pCompare;  /* The comparison operator */
+        Expr *pRight;    /* RHS of the comparison */
+        VdbeOp *pOp;     /* Opcode to access the value of the IN constraint */
+        int iIn;         /* IN loop corresponding to the j-th constraint */
+
+        /* Reload the constraint value into reg[iReg+j+2].  The same value
+        ** was loaded into the same register prior to the OP_VFilter, but
+        ** the xFilter implementation might have changed the datatype or
+        ** encoding of the value in the register, so it *must* be reloaded.
+        */
+        for(iIn=0; ALWAYS(iIn<pLevel->u.in.nIn); iIn++){
+          pOp = sqlite3VdbeGetOp(v, pLevel->u.in.aInLoop[iIn].addrInTop);
+          if( (pOp->opcode==OP_Column && pOp->p3==iReg+j+2)
+           || (pOp->opcode==OP_Rowid && pOp->p2==iReg+j+2)
+          ){
+            testcase( pOp->opcode==OP_Rowid );
+            sqlite3VdbeAddOp3(v, pOp->opcode, pOp->p1, pOp->p2, pOp->p3);
+            break;
+          }
+        }
+
+        /* Generate code that will continue to the next row if
+        ** the IN constraint is not satisfied
+        */
+        pCompare = sqlite3PExpr(pParse, TK_EQ, 0, 0);
+        if( !db->mallocFailed ){
+          int iFld = pTerm->u.x.iField;
+          Expr *pLeft = pTerm->pExpr->pLeft;
+          assert( pLeft!=0 );
+          if( iFld>0 ){
+            assert( pLeft->op==TK_VECTOR );
+            assert( ExprUseXList(pLeft) );
+            assert( iFld<=pLeft->x.pList->nExpr );
+            pCompare->pLeft = pLeft->x.pList->a[iFld-1].pExpr;
+          }else{
+            pCompare->pLeft = pLeft;
+          }
+          pCompare->pRight = pRight = sqlite3Expr(db, TK_REGISTER, 0);
+          if( pRight ){
+            pRight->iTable = iReg+j+2;
+            sqlite3ExprIfFalse(
+                pParse, pCompare, pLevel->addrCont, SQLITE_JUMPIFNULL
+            );
+          }
+          pCompare->pLeft = 0;
+        }
+        sqlite3ExprDelete(db, pCompare);
+      }
+    }
+
+    /* These registers need to be preserved in case there is an IN operator
+    ** loop.  So we could deallocate the registers here (and potentially
+    ** reuse them later) if (pLoop->wsFlags & WHERE_IN_ABLE)==0.  But it seems
+    ** simpler and safer to simply not reuse the registers.
+    **
+    **    sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2);
+    */
+  }else
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+  if( (pLoop->wsFlags & WHERE_IPK)!=0
+   && (pLoop->wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_EQ))!=0
+  ){
+    /* Case 2:  We can directly reference a single row using an
+    **          equality comparison against the ROWID field.  Or
+    **          we reference multiple rows using a "rowid IN (...)"
+    **          construct.
+    */
+    assert( pLoop->u.btree.nEq==1 );
+    pTerm = pLoop->aLTerm[0];
+    assert( pTerm!=0 );
+    assert( pTerm->pExpr!=0 );
+    testcase( pTerm->wtFlags & TERM_VIRTUAL );
+    iReleaseReg = ++pParse->nMem;
+    iRowidReg = codeEqualityTerm(pParse, pTerm, pLevel, 0, bRev, iReleaseReg);
+    if( iRowidReg!=iReleaseReg ) sqlite3ReleaseTempReg(pParse, iReleaseReg);
+    addrNxt = pLevel->addrNxt;
+    if( pLevel->regFilter ){
+      sqlite3VdbeAddOp2(v, OP_MustBeInt, iRowidReg, addrNxt);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp4Int(v, OP_Filter, pLevel->regFilter, addrNxt,
+                           iRowidReg, 1);
+      VdbeCoverage(v);
+      filterPullDown(pParse, pWInfo, iLevel, addrNxt, notReady);
+    }
+    sqlite3VdbeAddOp3(v, OP_SeekRowid, iCur, addrNxt, iRowidReg);
+    VdbeCoverage(v);
+    pLevel->op = OP_Noop;
+  }else if( (pLoop->wsFlags & WHERE_IPK)!=0
+         && (pLoop->wsFlags & WHERE_COLUMN_RANGE)!=0
+  ){
+    /* Case 3:  We have an inequality comparison against the ROWID field.
+    */
+    int testOp = OP_Noop;
+    int start;
+    int memEndValue = 0;
+    WhereTerm *pStart, *pEnd;
+
+    j = 0;
+    pStart = pEnd = 0;
+    if( pLoop->wsFlags & WHERE_BTM_LIMIT ) pStart = pLoop->aLTerm[j++];
+    if( pLoop->wsFlags & WHERE_TOP_LIMIT ) pEnd = pLoop->aLTerm[j++];
+    assert( pStart!=0 || pEnd!=0 );
+    if( bRev ){
+      pTerm = pStart;
+      pStart = pEnd;
+      pEnd = pTerm;
+    }
+    codeCursorHint(pTabItem, pWInfo, pLevel, pEnd);
+    if( pStart ){
+      Expr *pX;             /* The expression that defines the start bound */
+      int r1, rTemp;        /* Registers for holding the start boundary */
+      int op;               /* Cursor seek operation */
+
+      /* The following constant maps TK_xx codes into corresponding
+      ** seek opcodes.  It depends on a particular ordering of TK_xx
+      */
+      const u8 aMoveOp[] = {
+           /* TK_GT */  OP_SeekGT,
+           /* TK_LE */  OP_SeekLE,
+           /* TK_LT */  OP_SeekLT,
+           /* TK_GE */  OP_SeekGE
+      };
+      assert( TK_LE==TK_GT+1 );      /* Make sure the ordering.. */
+      assert( TK_LT==TK_GT+2 );      /*  ... of the TK_xx values... */
+      assert( TK_GE==TK_GT+3 );      /*  ... is correct. */
+
+      assert( (pStart->wtFlags & TERM_VNULL)==0 );
+      testcase( pStart->wtFlags & TERM_VIRTUAL );
+      pX = pStart->pExpr;
+      assert( pX!=0 );
+      testcase( pStart->leftCursor!=iCur ); /* transitive constraints */
+      if( sqlite3ExprIsVector(pX->pRight) ){
+        r1 = rTemp = sqlite3GetTempReg(pParse);
+        codeExprOrVector(pParse, pX->pRight, r1, 1);
+        testcase( pX->op==TK_GT );
+        testcase( pX->op==TK_GE );
+        testcase( pX->op==TK_LT );
+        testcase( pX->op==TK_LE );
+        op = aMoveOp[((pX->op - TK_GT - 1) & 0x3) | 0x1];
+        assert( pX->op!=TK_GT || op==OP_SeekGE );
+        assert( pX->op!=TK_GE || op==OP_SeekGE );
+        assert( pX->op!=TK_LT || op==OP_SeekLE );
+        assert( pX->op!=TK_LE || op==OP_SeekLE );
+      }else{
+        r1 = sqlite3ExprCodeTemp(pParse, pX->pRight, &rTemp);
+        disableTerm(pLevel, pStart);
+        op = aMoveOp[(pX->op - TK_GT)];
+      }
+      sqlite3VdbeAddOp3(v, op, iCur, addrBrk, r1);
+      VdbeComment((v, "pk"));
+      VdbeCoverageIf(v, pX->op==TK_GT);
+      VdbeCoverageIf(v, pX->op==TK_LE);
+      VdbeCoverageIf(v, pX->op==TK_LT);
+      VdbeCoverageIf(v, pX->op==TK_GE);
+      sqlite3ReleaseTempReg(pParse, rTemp);
+    }else{
+      sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, addrHalt);
+      VdbeCoverageIf(v, bRev==0);
+      VdbeCoverageIf(v, bRev!=0);
+    }
+    if( pEnd ){
+      Expr *pX;
+      pX = pEnd->pExpr;
+      assert( pX!=0 );
+      assert( (pEnd->wtFlags & TERM_VNULL)==0 );
+      testcase( pEnd->leftCursor!=iCur ); /* Transitive constraints */
+      testcase( pEnd->wtFlags & TERM_VIRTUAL );
+      memEndValue = ++pParse->nMem;
+      codeExprOrVector(pParse, pX->pRight, memEndValue, 1);
+      if( 0==sqlite3ExprIsVector(pX->pRight)
+       && (pX->op==TK_LT || pX->op==TK_GT)
+      ){
+        testOp = bRev ? OP_Le : OP_Ge;
+      }else{
+        testOp = bRev ? OP_Lt : OP_Gt;
+      }
+      if( 0==sqlite3ExprIsVector(pX->pRight) ){
+        disableTerm(pLevel, pEnd);
+      }
+    }
+    start = sqlite3VdbeCurrentAddr(v);
+    pLevel->op = bRev ? OP_Prev : OP_Next;
+    pLevel->p1 = iCur;
+    pLevel->p2 = start;
+    assert( pLevel->p5==0 );
+    if( testOp!=OP_Noop ){
+      iRowidReg = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg);
+      sqlite3VdbeAddOp3(v, testOp, memEndValue, addrBrk, iRowidReg);
+      VdbeCoverageIf(v, testOp==OP_Le);
+      VdbeCoverageIf(v, testOp==OP_Lt);
+      VdbeCoverageIf(v, testOp==OP_Ge);
+      VdbeCoverageIf(v, testOp==OP_Gt);
+      sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC | SQLITE_JUMPIFNULL);
+    }
+  }else if( pLoop->wsFlags & WHERE_INDEXED ){
+    /* Case 4: A scan using an index.
+    **
+    **         The WHERE clause may contain zero or more equality
+    **         terms ("==" or "IN" operators) that refer to the N
+    **         left-most columns of the index. It may also contain
+    **         inequality constraints (>, <, >= or <=) on the indexed
+    **         column that immediately follows the N equalities. Only
+    **         the right-most column can be an inequality - the rest must
+    **         use the "==" and "IN" operators. For example, if the
+    **         index is on (x,y,z), then the following clauses are all
+    **         optimized:
+    **
+    **            x=5
+    **            x=5 AND y=10
+    **            x=5 AND y<10
+    **            x=5 AND y>5 AND y<10
+    **            x=5 AND y=5 AND z<=10
+    **
+    **         The z<10 term of the following cannot be used, only
+    **         the x=5 term:
+    **
+    **            x=5 AND z<10
+    **
+    **         N may be zero if there are inequality constraints.
+    **         If there are no inequality constraints, then N is at
+    **         least one.
+    **
+    **         This case is also used when there are no WHERE clause
+    **         constraints but an index is selected anyway, in order
+    **         to force the output order to conform to an ORDER BY.
+    */
+    static const u8 aStartOp[] = {
+      0,
+      0,
+      OP_Rewind,           /* 2: (!start_constraints && startEq &&  !bRev) */
+      OP_Last,             /* 3: (!start_constraints && startEq &&   bRev) */
+      OP_SeekGT,           /* 4: (start_constraints  && !startEq && !bRev) */
+      OP_SeekLT,           /* 5: (start_constraints  && !startEq &&  bRev) */
+      OP_SeekGE,           /* 6: (start_constraints  &&  startEq && !bRev) */
+      OP_SeekLE            /* 7: (start_constraints  &&  startEq &&  bRev) */
+    };
+    static const u8 aEndOp[] = {
+      OP_IdxGE,            /* 0: (end_constraints && !bRev && !endEq) */
+      OP_IdxGT,            /* 1: (end_constraints && !bRev &&  endEq) */
+      OP_IdxLE,            /* 2: (end_constraints &&  bRev && !endEq) */
+      OP_IdxLT,            /* 3: (end_constraints &&  bRev &&  endEq) */
+    };
+    u16 nEq = pLoop->u.btree.nEq;     /* Number of == or IN terms */
+    u16 nBtm = pLoop->u.btree.nBtm;   /* Length of BTM vector */
+    u16 nTop = pLoop->u.btree.nTop;   /* Length of TOP vector */
+    int regBase;                 /* Base register holding constraint values */
+    WhereTerm *pRangeStart = 0;  /* Inequality constraint at range start */
+    WhereTerm *pRangeEnd = 0;    /* Inequality constraint at range end */
+    int startEq;                 /* True if range start uses ==, >= or <= */
+    int endEq;                   /* True if range end uses ==, >= or <= */
+    int start_constraints;       /* Start of range is constrained */
+    int nConstraint;             /* Number of constraint terms */
+    int iIdxCur;                 /* The VDBE cursor for the index */
+    int nExtraReg = 0;           /* Number of extra registers needed */
+    int op;                      /* Instruction opcode */
+    char *zStartAff;             /* Affinity for start of range constraint */
+    char *zEndAff = 0;           /* Affinity for end of range constraint */
+    u8 bSeekPastNull = 0;        /* True to seek past initial nulls */
+    u8 bStopAtNull = 0;          /* Add condition to terminate at NULLs */
+    int omitTable;               /* True if we use the index only */
+    int regBignull = 0;          /* big-null flag register */
+    int addrSeekScan = 0;        /* Opcode of the OP_SeekScan, if any */
+
+    pIdx = pLoop->u.btree.pIndex;
+    iIdxCur = pLevel->iIdxCur;
+    assert( nEq>=pLoop->nSkip );
+
+    /* Find any inequality constraint terms for the start and end
+    ** of the range.
+    */
+    j = nEq;
+    if( pLoop->wsFlags & WHERE_BTM_LIMIT ){
+      pRangeStart = pLoop->aLTerm[j++];
+      nExtraReg = MAX(nExtraReg, pLoop->u.btree.nBtm);
+      /* Like optimization range constraints always occur in pairs */
+      assert( (pRangeStart->wtFlags & TERM_LIKEOPT)==0 ||
+              (pLoop->wsFlags & WHERE_TOP_LIMIT)!=0 );
+    }
+    if( pLoop->wsFlags & WHERE_TOP_LIMIT ){
+      pRangeEnd = pLoop->aLTerm[j++];
+      nExtraReg = MAX(nExtraReg, pLoop->u.btree.nTop);
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+      if( (pRangeEnd->wtFlags & TERM_LIKEOPT)!=0 ){
+        assert( pRangeStart!=0 );                     /* LIKE opt constraints */
+        assert( pRangeStart->wtFlags & TERM_LIKEOPT );   /* occur in pairs */
+        pLevel->iLikeRepCntr = (u32)++pParse->nMem;
+        sqlite3VdbeAddOp2(v, OP_Integer, 1, (int)pLevel->iLikeRepCntr);
+        VdbeComment((v, "LIKE loop counter"));
+        pLevel->addrLikeRep = sqlite3VdbeCurrentAddr(v);
+        /* iLikeRepCntr actually stores 2x the counter register number.  The
+        ** bottom bit indicates whether the search order is ASC or DESC. */
+        testcase( bRev );
+        testcase( pIdx->aSortOrder[nEq]==SQLITE_SO_DESC );
+        assert( (bRev & ~1)==0 );
+        pLevel->iLikeRepCntr <<=1;
+        pLevel->iLikeRepCntr |= bRev ^ (pIdx->aSortOrder[nEq]==SQLITE_SO_DESC);
+      }
+#endif
+      if( pRangeStart==0 ){
+        j = pIdx->aiColumn[nEq];
+        if( (j>=0 && pIdx->pTable->aCol[j].notNull==0) || j==XN_EXPR ){
+          bSeekPastNull = 1;
+        }
+      }
+    }
+    assert( pRangeEnd==0 || (pRangeEnd->wtFlags & TERM_VNULL)==0 );
+
+    /* If the WHERE_BIGNULL_SORT flag is set, then index column nEq uses
+    ** a non-default "big-null" sort (either ASC NULLS LAST or DESC NULLS
+    ** FIRST). In both cases separate ordered scans are made of those
+    ** index entries for which the column is null and for those for which
+    ** it is not. For an ASC sort, the non-NULL entries are scanned first.
+    ** For DESC, NULL entries are scanned first.
+    */
+    if( (pLoop->wsFlags & (WHERE_TOP_LIMIT|WHERE_BTM_LIMIT))==0
+     && (pLoop->wsFlags & WHERE_BIGNULL_SORT)!=0
+    ){
+      assert( bSeekPastNull==0 && nExtraReg==0 && nBtm==0 && nTop==0 );
+      assert( pRangeEnd==0 && pRangeStart==0 );
+      testcase( pLoop->nSkip>0 );
+      nExtraReg = 1;
+      bSeekPastNull = 1;
+      pLevel->regBignull = regBignull = ++pParse->nMem;
+      if( pLevel->iLeftJoin ){
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, regBignull);
+      }
+      pLevel->addrBignull = sqlite3VdbeMakeLabel(pParse);
+    }
+
+    /* If we are doing a reverse order scan on an ascending index, or
+    ** a forward order scan on a descending index, interchange the
+    ** start and end terms (pRangeStart and pRangeEnd).
+    */
+    if( (nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC)) ){
+      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
+      SWAP(u8, bSeekPastNull, bStopAtNull);
+      SWAP(u8, nBtm, nTop);
+    }
+
+    if( iLevel>0 && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)!=0 ){
+      /* In case OP_SeekScan is used, ensure that the index cursor does not
+      ** point to a valid row for the first iteration of this loop. */
+      sqlite3VdbeAddOp1(v, OP_NullRow, iIdxCur);
+    }
+
+    /* Generate code to evaluate all constraint terms using == or IN
+    ** and store the values of those terms in an array of registers
+    ** starting at regBase.
+    */
+    codeCursorHint(pTabItem, pWInfo, pLevel, pRangeEnd);
+    regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);
+    assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq );
+    if( zStartAff && nTop ){
+      zEndAff = sqlite3DbStrDup(db, &zStartAff[nEq]);
+    }
+    addrNxt = (regBignull ? pLevel->addrBignull : pLevel->addrNxt);
+
+    testcase( pRangeStart && (pRangeStart->eOperator & WO_LE)!=0 );
+    testcase( pRangeStart && (pRangeStart->eOperator & WO_GE)!=0 );
+    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_LE)!=0 );
+    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_GE)!=0 );
+    startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
+    endEq =   !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
+    start_constraints = pRangeStart || nEq>0;
+
+    /* Seek the index cursor to the start of the range. */
+    nConstraint = nEq;
+    if( pRangeStart ){
+      Expr *pRight = pRangeStart->pExpr->pRight;
+      codeExprOrVector(pParse, pRight, regBase+nEq, nBtm);
+      whereLikeOptimizationStringFixup(v, pLevel, pRangeStart);
+      if( (pRangeStart->wtFlags & TERM_VNULL)==0
+       && sqlite3ExprCanBeNull(pRight)
+      ){
+        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
+        VdbeCoverage(v);
+      }
+      if( zStartAff ){
+        updateRangeAffinityStr(pRight, nBtm, &zStartAff[nEq]);
+      }
+      nConstraint += nBtm;
+      testcase( pRangeStart->wtFlags & TERM_VIRTUAL );
+      if( sqlite3ExprIsVector(pRight)==0 ){
+        disableTerm(pLevel, pRangeStart);
+      }else{
+        startEq = 1;
+      }
+      bSeekPastNull = 0;
+    }else if( bSeekPastNull ){
+      startEq = 0;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
+      start_constraints = 1;
+      nConstraint++;
+    }else if( regBignull ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
+      start_constraints = 1;
+      nConstraint++;
+    }
+    codeApplyAffinity(pParse, regBase, nConstraint - bSeekPastNull, zStartAff);
+    if( pLoop->nSkip>0 && nConstraint==pLoop->nSkip ){
+      /* The skip-scan logic inside the call to codeAllEqualityConstraints()
+      ** above has already left the cursor sitting on the correct row,
+      ** so no further seeking is needed */
+    }else{
+      if( regBignull ){
+        sqlite3VdbeAddOp2(v, OP_Integer, 1, regBignull);
+        VdbeComment((v, "NULL-scan pass ctr"));
+      }
+      if( pLevel->regFilter ){
+        sqlite3VdbeAddOp4Int(v, OP_Filter, pLevel->regFilter, addrNxt,
+                             regBase, nEq);
+        VdbeCoverage(v);
+        filterPullDown(pParse, pWInfo, iLevel, addrNxt, notReady);
+      }
+
+      op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
+      assert( op!=0 );
+      if( (pLoop->wsFlags & WHERE_IN_SEEKSCAN)!=0 && op==OP_SeekGE ){
+        assert( regBignull==0 );
+        /* TUNING:  The OP_SeekScan opcode seeks to reduce the number
+        ** of expensive seek operations by replacing a single seek with
+        ** 1 or more step operations.  The question is, how many steps
+        ** should we try before giving up and going with a seek.  The cost
+        ** of a seek is proportional to the logarithm of the of the number
+        ** of entries in the tree, so basing the number of steps to try
+        ** on the estimated number of rows in the btree seems like a good
+        ** guess. */
+        addrSeekScan = sqlite3VdbeAddOp1(v, OP_SeekScan,
+                                         (pIdx->aiRowLogEst[0]+9)/10);
+        if( pRangeStart || pRangeEnd ){
+          sqlite3VdbeChangeP5(v, 1);
+          sqlite3VdbeChangeP2(v, addrSeekScan, sqlite3VdbeCurrentAddr(v)+1);
+          addrSeekScan = 0;
+        }
+        VdbeCoverage(v);
+      }
+      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
+      VdbeCoverage(v);
+      VdbeCoverageIf(v, op==OP_Rewind);  testcase( op==OP_Rewind );
+      VdbeCoverageIf(v, op==OP_Last);    testcase( op==OP_Last );
+      VdbeCoverageIf(v, op==OP_SeekGT);  testcase( op==OP_SeekGT );
+      VdbeCoverageIf(v, op==OP_SeekGE);  testcase( op==OP_SeekGE );
+      VdbeCoverageIf(v, op==OP_SeekLE);  testcase( op==OP_SeekLE );
+      VdbeCoverageIf(v, op==OP_SeekLT);  testcase( op==OP_SeekLT );
+
+      assert( bSeekPastNull==0 || bStopAtNull==0 );
+      if( regBignull ){
+        assert( bSeekPastNull==1 || bStopAtNull==1 );
+        assert( bSeekPastNull==!bStopAtNull );
+        assert( bStopAtNull==startEq );
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+2);
+        op = aStartOp[(nConstraint>1)*4 + 2 + bRev];
+        sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase,
+                             nConstraint-startEq);
+        VdbeCoverage(v);
+        VdbeCoverageIf(v, op==OP_Rewind);  testcase( op==OP_Rewind );
+        VdbeCoverageIf(v, op==OP_Last);    testcase( op==OP_Last );
+        VdbeCoverageIf(v, op==OP_SeekGE);  testcase( op==OP_SeekGE );
+        VdbeCoverageIf(v, op==OP_SeekLE);  testcase( op==OP_SeekLE );
+        assert( op==OP_Rewind || op==OP_Last || op==OP_SeekGE || op==OP_SeekLE);
+      }
+    }
+
+    /* Load the value for the inequality constraint at the end of the
+    ** range (if any).
+    */
+    nConstraint = nEq;
+    assert( pLevel->p2==0 );
+    if( pRangeEnd ){
+      Expr *pRight = pRangeEnd->pExpr->pRight;
+      assert( addrSeekScan==0 );
+      codeExprOrVector(pParse, pRight, regBase+nEq, nTop);
+      whereLikeOptimizationStringFixup(v, pLevel, pRangeEnd);
+      if( (pRangeEnd->wtFlags & TERM_VNULL)==0
+       && sqlite3ExprCanBeNull(pRight)
+      ){
+        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
+        VdbeCoverage(v);
+      }
+      if( zEndAff ){
+        updateRangeAffinityStr(pRight, nTop, zEndAff);
+        codeApplyAffinity(pParse, regBase+nEq, nTop, zEndAff);
+      }else{
+        assert( pParse->db->mallocFailed );
+      }
+      nConstraint += nTop;
+      testcase( pRangeEnd->wtFlags & TERM_VIRTUAL );
+
+      if( sqlite3ExprIsVector(pRight)==0 ){
+        disableTerm(pLevel, pRangeEnd);
+      }else{
+        endEq = 1;
+      }
+    }else if( bStopAtNull ){
+      if( regBignull==0 ){
+        sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
+        endEq = 0;
+      }
+      nConstraint++;
+    }
+    if( zStartAff ) sqlite3DbNNFreeNN(db, zStartAff);
+    if( zEndAff ) sqlite3DbNNFreeNN(db, zEndAff);
+
+    /* Top of the loop body */
+    pLevel->p2 = sqlite3VdbeCurrentAddr(v);
+
+    /* Check if the index cursor is past the end of the range. */
+    if( nConstraint ){
+      if( regBignull ){
+        /* Except, skip the end-of-range check while doing the NULL-scan */
+        sqlite3VdbeAddOp2(v, OP_IfNot, regBignull, sqlite3VdbeCurrentAddr(v)+3);
+        VdbeComment((v, "If NULL-scan 2nd pass"));
+        VdbeCoverage(v);
+      }
+      op = aEndOp[bRev*2 + endEq];
+      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
+      testcase( op==OP_IdxGT );  VdbeCoverageIf(v, op==OP_IdxGT );
+      testcase( op==OP_IdxGE );  VdbeCoverageIf(v, op==OP_IdxGE );
+      testcase( op==OP_IdxLT );  VdbeCoverageIf(v, op==OP_IdxLT );
+      testcase( op==OP_IdxLE );  VdbeCoverageIf(v, op==OP_IdxLE );
+      if( addrSeekScan ) sqlite3VdbeJumpHere(v, addrSeekScan);
+    }
+    if( regBignull ){
+      /* During a NULL-scan, check to see if we have reached the end of
+      ** the NULLs */
+      assert( bSeekPastNull==!bStopAtNull );
+      assert( bSeekPastNull+bStopAtNull==1 );
+      assert( nConstraint+bSeekPastNull>0 );
+      sqlite3VdbeAddOp2(v, OP_If, regBignull, sqlite3VdbeCurrentAddr(v)+2);
+      VdbeComment((v, "If NULL-scan 1st pass"));
+      VdbeCoverage(v);
+      op = aEndOp[bRev*2 + bSeekPastNull];
+      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase,
+                           nConstraint+bSeekPastNull);
+      testcase( op==OP_IdxGT );  VdbeCoverageIf(v, op==OP_IdxGT );
+      testcase( op==OP_IdxGE );  VdbeCoverageIf(v, op==OP_IdxGE );
+      testcase( op==OP_IdxLT );  VdbeCoverageIf(v, op==OP_IdxLT );
+      testcase( op==OP_IdxLE );  VdbeCoverageIf(v, op==OP_IdxLE );
+    }
+
+    if( (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0 ){
+      sqlite3VdbeAddOp3(v, OP_SeekHit, iIdxCur, nEq, nEq);
+    }
+
+    /* Seek the table cursor, if required */
+    omitTable = (pLoop->wsFlags & WHERE_IDX_ONLY)!=0
+           && (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0;
+    if( omitTable ){
+      /* pIdx is a covering index.  No need to access the main table. */
+    }else if( HasRowid(pIdx->pTable) ){
+      codeDeferredSeek(pWInfo, pIdx, iCur, iIdxCur);
+    }else if( iCur!=iIdxCur ){
+      Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable);
+      iRowidReg = sqlite3GetTempRange(pParse, pPk->nKeyCol);
+      for(j=0; j<pPk->nKeyCol; j++){
+        k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[j]);
+        sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, iRowidReg+j);
+      }
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, iCur, addrCont,
+                           iRowidReg, pPk->nKeyCol); VdbeCoverage(v);
+    }
+
+    if( pLevel->iLeftJoin==0 ){
+      /* If a partial index is driving the loop, try to eliminate WHERE clause
+      ** terms from the query that must be true due to the WHERE clause of
+      ** the partial index.
+      **
+      ** 2019-11-02 ticket 623eff57e76d45f6: This optimization does not work
+      ** for a LEFT JOIN.
+      */
+      if( pIdx->pPartIdxWhere ){
+        whereApplyPartialIndexConstraints(pIdx->pPartIdxWhere, iCur, pWC);
+      }
+    }else{
+      testcase( pIdx->pPartIdxWhere );
+      /* The following assert() is not a requirement, merely an observation:
+      ** The OR-optimization doesn't work for the right hand table of
+      ** a LEFT JOIN: */
+      assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0 );
+    }
+
+    /* Record the instruction used to terminate the loop. */
+    if( (pLoop->wsFlags & WHERE_ONEROW)
+     || (pLevel->u.in.nIn && regBignull==0 && whereLoopIsOneRow(pLoop))
+    ){
+      pLevel->op = OP_Noop;
+    }else if( bRev ){
+      pLevel->op = OP_Prev;
+    }else{
+      pLevel->op = OP_Next;
+    }
+    pLevel->p1 = iIdxCur;
+    pLevel->p3 = (pLoop->wsFlags&WHERE_UNQ_WANTED)!=0 ? 1:0;
+    if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){
+      pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
+    }else{
+      assert( pLevel->p5==0 );
+    }
+    if( omitTable ) pIdx = 0;
+  }else
+
+#ifndef SQLITE_OMIT_OR_OPTIMIZATION
+  if( pLoop->wsFlags & WHERE_MULTI_OR ){
+    /* Case 5:  Two or more separately indexed terms connected by OR
+    **
+    ** Example:
+    **
+    **   CREATE TABLE t1(a,b,c,d);
+    **   CREATE INDEX i1 ON t1(a);
+    **   CREATE INDEX i2 ON t1(b);
+    **   CREATE INDEX i3 ON t1(c);
+    **
+    **   SELECT * FROM t1 WHERE a=5 OR b=7 OR (c=11 AND d=13)
+    **
+    ** In the example, there are three indexed terms connected by OR.
+    ** The top of the loop looks like this:
+    **
+    **          Null       1                # Zero the rowset in reg 1
+    **
+    ** Then, for each indexed term, the following. The arguments to
+    ** RowSetTest are such that the rowid of the current row is inserted
+    ** into the RowSet. If it is already present, control skips the
+    ** Gosub opcode and jumps straight to the code generated by WhereEnd().
+    **
+    **        sqlite3WhereBegin(<term>)
+    **          RowSetTest                  # Insert rowid into rowset
+    **          Gosub      2 A
+    **        sqlite3WhereEnd()
+    **
+    ** Following the above, code to terminate the loop. Label A, the target
+    ** of the Gosub above, jumps to the instruction right after the Goto.
+    **
+    **          Null       1                # Zero the rowset in reg 1
+    **          Goto       B                # The loop is finished.
+    **
+    **       A: <loop body>                 # Return data, whatever.
+    **
+    **          Return     2                # Jump back to the Gosub
+    **
+    **       B: <after the loop>
+    **
+    ** Added 2014-05-26: If the table is a WITHOUT ROWID table, then
+    ** use an ephemeral index instead of a RowSet to record the primary
+    ** keys of the rows we have already seen.
+    **
+    */
+    WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
+    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */
+    Index *pCov = 0;             /* Potential covering index (or NULL) */
+    int iCovCur = pParse->nTab++;  /* Cursor used for index scans (if any) */
+
+    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
+    int regRowset = 0;                        /* Register for RowSet object */
+    int regRowid = 0;                         /* Register holding rowid */
+    int iLoopBody = sqlite3VdbeMakeLabel(pParse);/* Start of loop body */
+    int iRetInit;                             /* Address of regReturn init */
+    int untestedTerms = 0;             /* Some terms not completely tested */
+    int ii;                            /* Loop counter */
+    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
+    Table *pTab = pTabItem->pSTab;
+
+    pTerm = pLoop->aLTerm[0];
+    assert( pTerm!=0 );
+    assert( pTerm->eOperator & WO_OR );
+    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
+    pOrWc = &pTerm->u.pOrInfo->wc;
+    pLevel->op = OP_Return;
+    pLevel->p1 = regReturn;
+
+    /* Set up a new SrcList in pOrTab containing the table being scanned
+    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
+    ** This becomes the SrcList in the recursive call to sqlite3WhereBegin().
+    */
+    if( pWInfo->nLevel>1 ){
+      int nNotReady;                 /* The number of notReady tables */
+      SrcItem *origSrc;              /* Original list of tables */
+      nNotReady = pWInfo->nLevel - iLevel - 1;
+      pOrTab = sqlite3DbMallocRawNN(db,
+                            sizeof(*pOrTab)+ nNotReady*sizeof(pOrTab->a[0]));
+      if( pOrTab==0 ) return notReady;
+      pOrTab->nAlloc = (u8)(nNotReady + 1);
+      pOrTab->nSrc = pOrTab->nAlloc;
+      memcpy(pOrTab->a, pTabItem, sizeof(*pTabItem));
+      origSrc = pWInfo->pTabList->a;
+      for(k=1; k<=nNotReady; k++){
+        memcpy(&pOrTab->a[k], &origSrc[pLevel[k].iFrom], sizeof(pOrTab->a[k]));
+      }
+    }else{
+      pOrTab = pWInfo->pTabList;
+    }
+
+    /* Initialize the rowset register to contain NULL. An SQL NULL is
+    ** equivalent to an empty rowset.  Or, create an ephemeral index
+    ** capable of holding primary keys in the case of a WITHOUT ROWID.
+    **
+    ** Also initialize regReturn to contain the address of the instruction
+    ** immediately following the OP_Return at the bottom of the loop. This
+    ** is required in a few obscure LEFT JOIN cases where control jumps
+    ** over the top of the loop into the body of it. In this case the
+    ** correct response for the end-of-loop code (the OP_Return) is to
+    ** fall through to the next instruction, just as an OP_Next does if
+    ** called on an uninitialized cursor.
+    */
+    if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
+      if( HasRowid(pTab) ){
+        regRowset = ++pParse->nMem;
+        sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset);
+      }else{
+        Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+        regRowset = pParse->nTab++;
+        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, regRowset, pPk->nKeyCol);
+        sqlite3VdbeSetP4KeyInfo(pParse, pPk);
+      }
+      regRowid = ++pParse->nMem;
+    }
+    iRetInit = sqlite3VdbeAddOp2(v, OP_Integer, 0, regReturn);
+
+    /* If the original WHERE clause is z of the form:  (x1 OR x2 OR ...) AND y
+    ** Then for every term xN, evaluate as the subexpression: xN AND y
+    ** That way, terms in y that are factored into the disjunction will
+    ** be picked up by the recursive calls to sqlite3WhereBegin() below.
+    **
+    ** Actually, each subexpression is converted to "xN AND w" where w is
+    ** the "interesting" terms of z - terms that did not originate in the
+    ** ON or USING clause of a LEFT JOIN, and terms that are usable as
+    ** indices.
+    **
+    ** This optimization also only applies if the (x1 OR x2 OR ...) term
+    ** is not contained in the ON clause of a LEFT JOIN.
+    ** See ticket http://www.sqlite.org/src/info/f2369304e4
+    **
+    ** 2022-02-04:  Do not push down slices of a row-value comparison.
+    ** In other words, "w" or "y" may not be a slice of a vector.  Otherwise,
+    ** the initialization of the right-hand operand of the vector comparison
+    ** might not occur, or might occur only in an OR branch that is not
+    ** taken.  dbsqlfuzz 80a9fade844b4fb43564efc972bcb2c68270f5d1.
+    **
+    ** 2022-03-03:  Do not push down expressions that involve subqueries.
+    ** The subquery might get coded as a subroutine.  Any table-references
+    ** in the subquery might be resolved to index-references for the index on
+    ** the OR branch in which the subroutine is coded.  But if the subroutine
+    ** is invoked from a different OR branch that uses a different index, such
+    ** index-references will not work.  tag-20220303a
+    ** https://sqlite.org/forum/forumpost/36937b197273d403
+    */
+    if( pWC->nTerm>1 ){
+      int iTerm;
+      for(iTerm=0; iTerm<pWC->nTerm; iTerm++){
+        Expr *pExpr = pWC->a[iTerm].pExpr;
+        if( &pWC->a[iTerm] == pTerm ) continue;
+        testcase( pWC->a[iTerm].wtFlags & TERM_VIRTUAL );
+        testcase( pWC->a[iTerm].wtFlags & TERM_CODED );
+        testcase( pWC->a[iTerm].wtFlags & TERM_SLICE );
+        if( (pWC->a[iTerm].wtFlags & (TERM_VIRTUAL|TERM_CODED|TERM_SLICE))!=0 ){
+          continue;
+        }
+        if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue;
+        if( ExprHasProperty(pExpr, EP_Subquery) ) continue;  /* tag-20220303a */
+        pExpr = sqlite3ExprDup(db, pExpr, 0);
+        pAndExpr = sqlite3ExprAnd(pParse, pAndExpr, pExpr);
+      }
+      if( pAndExpr ){
+        /* The extra 0x10000 bit on the opcode is masked off and does not
+        ** become part of the new Expr.op.  However, it does make the
+        ** op==TK_AND comparison inside of sqlite3PExpr() false, and this
+        ** prevents sqlite3PExpr() from applying the AND short-circuit
+        ** optimization, which we do not want here. */
+        pAndExpr = sqlite3PExpr(pParse, TK_AND|0x10000, 0, pAndExpr);
+      }
+    }
+
+    /* Run a separate WHERE clause for each term of the OR clause.  After
+    ** eliminating duplicates from other WHERE clauses, the action for each
+    ** sub-WHERE clause is to to invoke the main loop body as a subroutine.
+    */
+    ExplainQueryPlan((pParse, 1, "MULTI-INDEX OR"));
+    for(ii=0; ii<pOrWc->nTerm; ii++){
+      WhereTerm *pOrTerm = &pOrWc->a[ii];
+      if( pOrTerm->leftCursor==iCur || (pOrTerm->eOperator & WO_AND)!=0 ){
+        WhereInfo *pSubWInfo;           /* Info for single OR-term scan */
+        Expr *pOrExpr = pOrTerm->pExpr; /* Current OR clause term */
+        Expr *pDelete;                  /* Local copy of OR clause term */
+        int jmp1 = 0;                   /* Address of jump operation */
+        testcase( (pTabItem[0].fg.jointype & JT_LEFT)!=0
+               && !ExprHasProperty(pOrExpr, EP_OuterON)
+        ); /* See TH3 vtab25.400 and ticket 614b25314c766238 */
+        pDelete = pOrExpr = sqlite3ExprDup(db, pOrExpr, 0);
+        if( db->mallocFailed ){
+          sqlite3ExprDelete(db, pDelete);
+          continue;
+        }
+        if( pAndExpr ){
+          pAndExpr->pLeft = pOrExpr;
+          pOrExpr = pAndExpr;
+        }
+        /* Loop through table entries that match term pOrTerm. */
+        ExplainQueryPlan((pParse, 1, "INDEX %d", ii+1));
+        WHERETRACE(0xffffffff, ("Subplan for OR-clause:\n"));
+        pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0, 0,
+                                      WHERE_OR_SUBCLAUSE, iCovCur);
+        assert( pSubWInfo || pParse->nErr );
+        if( pSubWInfo ){
+          WhereLoop *pSubLoop;
+          int addrExplain = sqlite3WhereExplainOneScan(
+              pParse, pOrTab, &pSubWInfo->a[0], 0
+          );
+          sqlite3WhereAddScanStatus(v, pOrTab, &pSubWInfo->a[0], addrExplain);
+
+          /* This is the sub-WHERE clause body.  First skip over
+          ** duplicate rows from prior sub-WHERE clauses, and record the
+          ** rowid (or PRIMARY KEY) for the current row so that the same
+          ** row will be skipped in subsequent sub-WHERE clauses.
+          */
+          if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
+            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
+            if( HasRowid(pTab) ){
+              sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, regRowid);
+              jmp1 = sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, 0,
+                                          regRowid, iSet);
+              VdbeCoverage(v);
+            }else{
+              Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+              int nPk = pPk->nKeyCol;
+              int iPk;
+              int r;
+
+              /* Read the PK into an array of temp registers. */
+              r = sqlite3GetTempRange(pParse, nPk);
+              for(iPk=0; iPk<nPk; iPk++){
+                int iCol = pPk->aiColumn[iPk];
+                sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+iPk);
+              }
+
+              /* Check if the temp table already contains this key. If so,
+              ** the row has already been included in the result set and
+              ** can be ignored (by jumping past the Gosub below). Otherwise,
+              ** insert the key into the temp table and proceed with processing
+              ** the row.
+              **
+              ** Use some of the same optimizations as OP_RowSetTest: If iSet
+              ** is zero, assume that the key cannot already be present in
+              ** the temp table. And if iSet is -1, assume that there is no
+              ** need to insert the key into the temp table, as it will never
+              ** be tested for.  */
+              if( iSet ){
+                jmp1 = sqlite3VdbeAddOp4Int(v, OP_Found, regRowset, 0, r, nPk);
+                VdbeCoverage(v);
+              }
+              if( iSet>=0 ){
+                sqlite3VdbeAddOp3(v, OP_MakeRecord, r, nPk, regRowid);
+                sqlite3VdbeAddOp4Int(v, OP_IdxInsert, regRowset, regRowid,
+                                     r, nPk);
+                if( iSet ) sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+              }
+
+              /* Release the array of temp registers */
+              sqlite3ReleaseTempRange(pParse, r, nPk);
+            }
+          }
+
+          /* Invoke the main loop body as a subroutine */
+          sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);
+
+          /* Jump here (skipping the main loop body subroutine) if the
+          ** current sub-WHERE row is a duplicate from prior sub-WHEREs. */
+          if( jmp1 ) sqlite3VdbeJumpHere(v, jmp1);
+
+          /* The pSubWInfo->untestedTerms flag means that this OR term
+          ** contained one or more AND term from a notReady table.  The
+          ** terms from the notReady table could not be tested and will
+          ** need to be tested later.
+          */
+          if( pSubWInfo->untestedTerms ) untestedTerms = 1;
+
+          /* If all of the OR-connected terms are optimized using the same
+          ** index, and the index is opened using the same cursor number
+          ** by each call to sqlite3WhereBegin() made by this loop, it may
+          ** be possible to use that index as a covering index.
+          **
+          ** If the call to sqlite3WhereBegin() above resulted in a scan that
+          ** uses an index, and this is either the first OR-connected term
+          ** processed or the index is the same as that used by all previous
+          ** terms, set pCov to the candidate covering index. Otherwise, set
+          ** pCov to NULL to indicate that no candidate covering index will
+          ** be available.
+          */
+          pSubLoop = pSubWInfo->a[0].pWLoop;
+          assert( (pSubLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
+          if( (pSubLoop->wsFlags & WHERE_INDEXED)!=0
+           && (ii==0 || pSubLoop->u.btree.pIndex==pCov)
+           && (HasRowid(pTab) || !IsPrimaryKeyIndex(pSubLoop->u.btree.pIndex))
+          ){
+            assert( pSubWInfo->a[0].iIdxCur==iCovCur );
+            pCov = pSubLoop->u.btree.pIndex;
+          }else{
+            pCov = 0;
+          }
+          if( sqlite3WhereUsesDeferredSeek(pSubWInfo) ){
+            pWInfo->bDeferredSeek = 1;
+          }
+
+          /* Finish the loop through table entries that match term pOrTerm. */
+          sqlite3WhereEnd(pSubWInfo);
+          ExplainQueryPlanPop(pParse);
+        }
+        sqlite3ExprDelete(db, pDelete);
+      }
+    }
+    ExplainQueryPlanPop(pParse);
+    assert( pLevel->pWLoop==pLoop );
+    assert( (pLoop->wsFlags & WHERE_MULTI_OR)!=0 );
+    assert( (pLoop->wsFlags & WHERE_IN_ABLE)==0 );
+    pLevel->u.pCoveringIdx = pCov;
+    if( pCov ) pLevel->iIdxCur = iCovCur;
+    if( pAndExpr ){
+      pAndExpr->pLeft = 0;
+      sqlite3ExprDelete(db, pAndExpr);
+    }
+    sqlite3VdbeChangeP1(v, iRetInit, sqlite3VdbeCurrentAddr(v));
+    sqlite3VdbeGoto(v, pLevel->addrBrk);
+    sqlite3VdbeResolveLabel(v, iLoopBody);
+
+    /* Set the P2 operand of the OP_Return opcode that will end the current
+    ** loop to point to this spot, which is the top of the next containing
+    ** loop.  The byte-code formatter will use that P2 value as a hint to
+    ** indent everything in between the this point and the final OP_Return.
+    ** See tag-20220407a in vdbe.c and shell.c */
+    assert( pLevel->op==OP_Return );
+    pLevel->p2 = sqlite3VdbeCurrentAddr(v);
+
+    if( pWInfo->nLevel>1 ){ sqlite3DbFreeNN(db, pOrTab); }
+    if( !untestedTerms ) disableTerm(pLevel, pTerm);
+  }else
+#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
+
+  {
+    /* Case 6:  There is no usable index.  We must do a complete
+    **          scan of the entire table.
+    */
+    static const u8 aStep[] = { OP_Next, OP_Prev };
+    static const u8 aStart[] = { OP_Rewind, OP_Last };
+    assert( bRev==0 || bRev==1 );
+    if( pTabItem->fg.isRecursive ){
+      /* Tables marked isRecursive have only a single row that is stored in
+      ** a pseudo-cursor.  No need to Rewind or Next such cursors. */
+      pLevel->op = OP_Noop;
+    }else{
+      codeCursorHint(pTabItem, pWInfo, pLevel, 0);
+      pLevel->op = aStep[bRev];
+      pLevel->p1 = iCur;
+      pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrHalt);
+      VdbeCoverageIf(v, bRev==0);
+      VdbeCoverageIf(v, bRev!=0);
+      pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
+    }
+  }
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  pLevel->addrVisit = sqlite3VdbeCurrentAddr(v);
+#endif
+
+  /* Insert code to test every subexpression that can be completely
+  ** computed using the current set of tables.
+  **
+  ** This loop may run between one and three times, depending on the
+  ** constraints to be generated. The value of stack variable iLoop
+  ** determines the constraints coded by each iteration, as follows:
+  **
+  ** iLoop==1: Code only expressions that are entirely covered by pIdx.
+  ** iLoop==2: Code remaining expressions that do not contain correlated
+  **           sub-queries.
+  ** iLoop==3: Code all remaining expressions.
+  **
+  ** An effort is made to skip unnecessary iterations of the loop.
+  **
+  ** This optimization of causing simple query restrictions to occur before
+  ** more complex one is call the "push-down" optimization in MySQL.  Here
+  ** in SQLite, the name is "MySQL push-down", since there is also another
+  ** totally unrelated optimization called "WHERE-clause push-down".
+  ** Sometimes the qualifier is omitted, resulting in an ambiguity, so beware.
+  */
+  iLoop = (pIdx ? 1 : 2);
+  do{
+    int iNext = 0;                /* Next value for iLoop */
+    for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
+      Expr *pE;
+      int skipLikeAddr = 0;
+      testcase( pTerm->wtFlags & TERM_VIRTUAL );
+      testcase( pTerm->wtFlags & TERM_CODED );
+      if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+      if( (pTerm->prereqAll & pLevel->notReady)!=0 ){
+        testcase( pWInfo->untestedTerms==0
+            && (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)!=0 );
+        pWInfo->untestedTerms = 1;
+        continue;
+      }
+      pE = pTerm->pExpr;
+      assert( pE!=0 );
+      if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT) ){
+        if( !ExprHasProperty(pE,EP_OuterON|EP_InnerON) ){
+          /* Defer processing WHERE clause constraints until after outer
+          ** join processing.  tag-20220513a */
+          continue;
+        }else if( (pTabItem->fg.jointype & JT_LEFT)==JT_LEFT
+               && !ExprHasProperty(pE,EP_OuterON) ){
+          continue;
+        }else{
+          Bitmask m = sqlite3WhereGetMask(&pWInfo->sMaskSet, pE->w.iJoin);
+          if( m & pLevel->notReady ){
+            /* An ON clause that is not ripe */
+            continue;
+          }
+        }
+      }
+      if( iLoop==1 && !sqlite3ExprCoveredByIndex(pE, pLevel->iTabCur, pIdx) ){
+        iNext = 2;
+        continue;
+      }
+      if( iLoop<3 && (pTerm->wtFlags & TERM_VARSELECT) ){
+        if( iNext==0 ) iNext = 3;
+        continue;
+      }
+
+      if( (pTerm->wtFlags & TERM_LIKECOND)!=0 ){
+        /* If the TERM_LIKECOND flag is set, that means that the range search
+        ** is sufficient to guarantee that the LIKE operator is true, so we
+        ** can skip the call to the like(A,B) function.  But this only works
+        ** for strings.  So do not skip the call to the function on the pass
+        ** that compares BLOBs. */
+#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+        continue;
+#else
+        u32 x = pLevel->iLikeRepCntr;
+        if( x>0 ){
+          skipLikeAddr = sqlite3VdbeAddOp1(v, (x&1)?OP_IfNot:OP_If,(int)(x>>1));
+          VdbeCoverageIf(v, (x&1)==1);
+          VdbeCoverageIf(v, (x&1)==0);
+        }
+#endif
+      }
+#ifdef WHERETRACE_ENABLED /* 0xffffffff */
+      if( sqlite3WhereTrace ){
+        VdbeNoopComment((v, "WhereTerm[%d] (%p) priority=%d",
+                         pWC->nTerm-j, pTerm, iLoop));
+      }
+      if( sqlite3WhereTrace & 0x4000 ){
+        sqlite3DebugPrintf("Coding auxiliary constraint:\n");
+        sqlite3WhereTermPrint(pTerm, pWC->nTerm-j);
+      }
+#endif
+      sqlite3ExprIfFalse(pParse, pE, addrCont, SQLITE_JUMPIFNULL);
+      if( skipLikeAddr ) sqlite3VdbeJumpHere(v, skipLikeAddr);
+      pTerm->wtFlags |= TERM_CODED;
+    }
+    iLoop = iNext;
+  }while( iLoop>0 );
+
+  /* Insert code to test for implied constraints based on transitivity
+  ** of the "==" operator.
+  **
+  ** Example: If the WHERE clause contains "t1.a=t2.b" and "t2.b=123"
+  ** and we are coding the t1 loop and the t2 loop has not yet coded,
+  ** then we cannot use the "t1.a=t2.b" constraint, but we can code
+  ** the implied "t1.a=123" constraint.
+  */
+  for(pTerm=pWC->a, j=pWC->nBase; j>0; j--, pTerm++){
+    Expr *pE, sEAlt;
+    WhereTerm *pAlt;
+    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+    if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) continue;
+    if( (pTerm->eOperator & WO_EQUIV)==0 ) continue;
+    if( pTerm->leftCursor!=iCur ) continue;
+    if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT) ) continue;
+    pE = pTerm->pExpr;
+#ifdef WHERETRACE_ENABLED /* 0x4001 */
+    if( (sqlite3WhereTrace & 0x4001)==0x4001 ){
+      sqlite3DebugPrintf("Coding transitive constraint:\n");
+      sqlite3WhereTermPrint(pTerm, pWC->nTerm-j);
+    }
+#endif
+    assert( !ExprHasProperty(pE, EP_OuterON) );
+    assert( (pTerm->prereqRight & pLevel->notReady)!=0 );
+    assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+    pAlt = sqlite3WhereFindTerm(pWC, iCur, pTerm->u.x.leftColumn, notReady,
+                    WO_EQ|WO_IN|WO_IS, 0);
+    if( pAlt==0 ) continue;
+    if( pAlt->wtFlags & (TERM_CODED) ) continue;
+    if( (pAlt->eOperator & WO_IN)
+     && ExprUseXSelect(pAlt->pExpr)
+     && (pAlt->pExpr->x.pSelect->pEList->nExpr>1)
+    ){
+      continue;
+    }
+    testcase( pAlt->eOperator & WO_EQ );
+    testcase( pAlt->eOperator & WO_IS );
+    testcase( pAlt->eOperator & WO_IN );
+    VdbeModuleComment((v, "begin transitive constraint"));
+    sEAlt = *pAlt->pExpr;
+    sEAlt.pLeft = pE->pLeft;
+    sqlite3ExprIfFalse(pParse, &sEAlt, addrCont, SQLITE_JUMPIFNULL);
+    pAlt->wtFlags |= TERM_CODED;
+  }
+
+  /* For a RIGHT OUTER JOIN, record the fact that the current row has
+  ** been matched at least once.
+  */
+  if( pLevel->pRJ ){
+    Table *pTab;
+    int nPk;
+    int r;
+    int jmp1 = 0;
+    WhereRightJoin *pRJ = pLevel->pRJ;
+
+    /* pTab is the right-hand table of the RIGHT JOIN.  Generate code that
+    ** will record that the current row of that table has been matched at
+    ** least once.  This is accomplished by storing the PK for the row in
+    ** both the iMatch index and the regBloom Bloom filter.
+    */
+    pTab = pWInfo->pTabList->a[pLevel->iFrom].pSTab;
+    if( HasRowid(pTab) ){
+      r = sqlite3GetTempRange(pParse, 2);
+      sqlite3ExprCodeGetColumnOfTable(v, pTab, pLevel->iTabCur, -1, r+1);
+      nPk = 1;
+    }else{
+      int iPk;
+      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+      nPk = pPk->nKeyCol;
+      r = sqlite3GetTempRange(pParse, nPk+1);
+      for(iPk=0; iPk<nPk; iPk++){
+        int iCol = pPk->aiColumn[iPk];
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+1+iPk);
+      }
+    }
+    jmp1 = sqlite3VdbeAddOp4Int(v, OP_Found, pRJ->iMatch, 0, r+1, nPk);
+    VdbeCoverage(v);
+    VdbeComment((v, "match against %s", pTab->zName));
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, r+1, nPk, r);
+    sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pRJ->iMatch, r, r+1, nPk);
+    sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pRJ->regBloom, 0, r+1, nPk);
+    sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+    sqlite3VdbeJumpHere(v, jmp1);
+    sqlite3ReleaseTempRange(pParse, r, nPk+1);
+  }
+
+  /* For a LEFT OUTER JOIN, generate code that will record the fact that
+  ** at least one row of the right table has matched the left table.
+  */
+  if( pLevel->iLeftJoin ){
+    pLevel->addrFirst = sqlite3VdbeCurrentAddr(v);
+    sqlite3VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
+    VdbeComment((v, "record LEFT JOIN hit"));
+    if( pLevel->pRJ==0 ){
+      goto code_outer_join_constraints; /* WHERE clause constraints */
+    }
+  }
+
+  if( pLevel->pRJ ){
+    /* Create a subroutine used to process all interior loops and code
+    ** of the RIGHT JOIN.  During normal operation, the subroutine will
+    ** be in-line with the rest of the code.  But at the end, a separate
+    ** loop will run that invokes this subroutine for unmatched rows
+    ** of pTab, with all tables to left begin set to NULL.
+    */
+    WhereRightJoin *pRJ = pLevel->pRJ;
+    sqlite3VdbeAddOp2(v, OP_BeginSubrtn, 0, pRJ->regReturn);
+    pRJ->addrSubrtn = sqlite3VdbeCurrentAddr(v);
+    assert( pParse->withinRJSubrtn < 255 );
+    pParse->withinRJSubrtn++;
+
+    /* WHERE clause constraints must be deferred until after outer join
+    ** row elimination has completed, since WHERE clause constraints apply
+    ** to the results of the OUTER JOIN.  The following loop generates the
+    ** appropriate WHERE clause constraint checks.  tag-20220513a.
+    */
+  code_outer_join_constraints:
+    for(pTerm=pWC->a, j=0; j<pWC->nBase; j++, pTerm++){
+      testcase( pTerm->wtFlags & TERM_VIRTUAL );
+      testcase( pTerm->wtFlags & TERM_CODED );
+      if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+      if( (pTerm->prereqAll & pLevel->notReady)!=0 ){
+        assert( pWInfo->untestedTerms );
+        continue;
+      }
+      if( pTabItem->fg.jointype & JT_LTORJ ) continue;
+      assert( pTerm->pExpr );
+      sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
+      pTerm->wtFlags |= TERM_CODED;
+    }
+  }
+
+#if WHERETRACE_ENABLED /* 0x4001 */
+  if( sqlite3WhereTrace & 0x4000 ){
+    sqlite3DebugPrintf("All WHERE-clause terms after coding level %d:\n",
+                       iLevel);
+    sqlite3WhereClausePrint(pWC);
+  }
+  if( sqlite3WhereTrace & 0x1 ){
+    sqlite3DebugPrintf("End Coding level %d:  notReady=%llx\n",
+       iLevel, (u64)pLevel->notReady);
+  }
+#endif
+  return pLevel->notReady;
+}
+
+/*
+** Generate the code for the loop that finds all non-matched terms
+** for a RIGHT JOIN.
+*/
+SQLITE_PRIVATE SQLITE_NOINLINE void sqlite3WhereRightJoinLoop(
+  WhereInfo *pWInfo,
+  int iLevel,
+  WhereLevel *pLevel
+){
+  Parse *pParse = pWInfo->pParse;
+  Vdbe *v = pParse->pVdbe;
+  WhereRightJoin *pRJ = pLevel->pRJ;
+  Expr *pSubWhere = 0;
+  WhereClause *pWC = &pWInfo->sWC;
+  WhereInfo *pSubWInfo;
+  WhereLoop *pLoop = pLevel->pWLoop;
+  SrcItem *pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
+  SrcList sFrom;
+  Bitmask mAll = 0;
+  int k;
+
+  ExplainQueryPlan((pParse, 1, "RIGHT-JOIN %s", pTabItem->pSTab->zName));
+  sqlite3VdbeNoJumpsOutsideSubrtn(v, pRJ->addrSubrtn, pRJ->endSubrtn,
+                                  pRJ->regReturn);
+  for(k=0; k<iLevel; k++){
+    int iIdxCur;
+    SrcItem *pRight;
+    assert( pWInfo->a[k].pWLoop->iTab == pWInfo->a[k].iFrom );
+    pRight = &pWInfo->pTabList->a[pWInfo->a[k].iFrom];
+    mAll |= pWInfo->a[k].pWLoop->maskSelf;
+    if( pRight->fg.viaCoroutine ){
+      Subquery *pSubq;
+      assert( pRight->fg.isSubquery && pRight->u4.pSubq!=0 );
+      pSubq = pRight->u4.pSubq;
+      assert( pSubq->pSelect!=0 && pSubq->pSelect->pEList!=0 );
+      sqlite3VdbeAddOp3(
+          v, OP_Null, 0, pSubq->regResult,
+          pSubq->regResult + pSubq->pSelect->pEList->nExpr-1
+      );
+    }
+    sqlite3VdbeAddOp1(v, OP_NullRow, pWInfo->a[k].iTabCur);
+    iIdxCur = pWInfo->a[k].iIdxCur;
+    if( iIdxCur ){
+      sqlite3VdbeAddOp1(v, OP_NullRow, iIdxCur);
+    }
+  }
+  if( (pTabItem->fg.jointype & JT_LTORJ)==0 ){
+    mAll |= pLoop->maskSelf;
+    for(k=0; k<pWC->nTerm; k++){
+      WhereTerm *pTerm = &pWC->a[k];
+      if( (pTerm->wtFlags & (TERM_VIRTUAL|TERM_SLICE))!=0
+       && pTerm->eOperator!=WO_ROWVAL
+      ){
+        break;
+      }
+      if( pTerm->prereqAll & ~mAll ) continue;
+      if( ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON) ) continue;
+      pSubWhere = sqlite3ExprAnd(pParse, pSubWhere,
+                                 sqlite3ExprDup(pParse->db, pTerm->pExpr, 0));
+    }
+  }
+  sFrom.nSrc = 1;
+  sFrom.nAlloc = 1;
+  memcpy(&sFrom.a[0], pTabItem, sizeof(SrcItem));
+  sFrom.a[0].fg.jointype = 0;
+  assert( pParse->withinRJSubrtn < 100 );
+  pParse->withinRJSubrtn++;
+  pSubWInfo = sqlite3WhereBegin(pParse, &sFrom, pSubWhere, 0, 0, 0,
+                                WHERE_RIGHT_JOIN, 0);
+  if( pSubWInfo ){
+    int iCur = pLevel->iTabCur;
+    int r = ++pParse->nMem;
+    int nPk;
+    int jmp;
+    int addrCont = sqlite3WhereContinueLabel(pSubWInfo);
+    Table *pTab = pTabItem->pSTab;
+    if( HasRowid(pTab) ){
+      sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, r);
+      nPk = 1;
+    }else{
+      int iPk;
+      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+      nPk = pPk->nKeyCol;
+      pParse->nMem += nPk - 1;
+      for(iPk=0; iPk<nPk; iPk++){
+        int iCol = pPk->aiColumn[iPk];
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+iPk);
+      }
+    }
+    jmp = sqlite3VdbeAddOp4Int(v, OP_Filter, pRJ->regBloom, 0, r, nPk);
+    VdbeCoverage(v);
+    sqlite3VdbeAddOp4Int(v, OP_Found, pRJ->iMatch, addrCont, r, nPk);
+    VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, jmp);
+    sqlite3VdbeAddOp2(v, OP_Gosub, pRJ->regReturn, pRJ->addrSubrtn);
+    sqlite3WhereEnd(pSubWInfo);
+  }
+  sqlite3ExprDelete(pParse->db, pSubWhere);
+  ExplainQueryPlanPop(pParse);
+  assert( pParse->withinRJSubrtn>0 );
+  pParse->withinRJSubrtn--;
+}
+
+/************** End of wherecode.c *******************************************/
+/************** Begin file whereexpr.c ***************************************/
+/*
+** 2015-06-08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This module contains C code that generates VDBE code used to process
+** the WHERE clause of SQL statements.
+**
+** This file was originally part of where.c but was split out to improve
+** readability and editability.  This file contains utility routines for
+** analyzing Expr objects in the WHERE clause.
+*/
+/* #include "sqliteInt.h" */
+/* #include "whereInt.h" */
+
+/* Forward declarations */
+static void exprAnalyze(SrcList*, WhereClause*, int);
+
+/*
+** Deallocate all memory associated with a WhereOrInfo object.
+*/
+static void whereOrInfoDelete(sqlite3 *db, WhereOrInfo *p){
+  sqlite3WhereClauseClear(&p->wc);
+  sqlite3DbFree(db, p);
+}
+
+/*
+** Deallocate all memory associated with a WhereAndInfo object.
+*/
+static void whereAndInfoDelete(sqlite3 *db, WhereAndInfo *p){
+  sqlite3WhereClauseClear(&p->wc);
+  sqlite3DbFree(db, p);
+}
+
+/*
+** Add a single new WhereTerm entry to the WhereClause object pWC.
+** The new WhereTerm object is constructed from Expr p and with wtFlags.
+** The index in pWC->a[] of the new WhereTerm is returned on success.
+** 0 is returned if the new WhereTerm could not be added due to a memory
+** allocation error.  The memory allocation failure will be recorded in
+** the db->mallocFailed flag so that higher-level functions can detect it.
+**
+** This routine will increase the size of the pWC->a[] array as necessary.
+**
+** If the wtFlags argument includes TERM_DYNAMIC, then responsibility
+** for freeing the expression p is assumed by the WhereClause object pWC.
+** This is true even if this routine fails to allocate a new WhereTerm.
+**
+** WARNING:  This routine might reallocate the space used to store
+** WhereTerms.  All pointers to WhereTerms should be invalidated after
+** calling this routine.  Such pointers may be reinitialized by referencing
+** the pWC->a[] array.
+*/
+static int whereClauseInsert(WhereClause *pWC, Expr *p, u16 wtFlags){
+  WhereTerm *pTerm;
+  int idx;
+  testcase( wtFlags & TERM_VIRTUAL );
+  if( pWC->nTerm>=pWC->nSlot ){
+    WhereTerm *pOld = pWC->a;
+    sqlite3 *db = pWC->pWInfo->pParse->db;
+    pWC->a = sqlite3WhereMalloc(pWC->pWInfo, sizeof(pWC->a[0])*pWC->nSlot*2 );
+    if( pWC->a==0 ){
+      if( wtFlags & TERM_DYNAMIC ){
+        sqlite3ExprDelete(db, p);
+      }
+      pWC->a = pOld;
+      return 0;
+    }
+    memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
+    pWC->nSlot = pWC->nSlot*2;
+  }
+  pTerm = &pWC->a[idx = pWC->nTerm++];
+  if( (wtFlags & TERM_VIRTUAL)==0 ) pWC->nBase = pWC->nTerm;
+  if( p && ExprHasProperty(p, EP_Unlikely) ){
+    pTerm->truthProb = sqlite3LogEst(p->iTable) - 270;
+  }else{
+    pTerm->truthProb = 1;
+  }
+  pTerm->pExpr = sqlite3ExprSkipCollateAndLikely(p);
+  pTerm->wtFlags = wtFlags;
+  pTerm->pWC = pWC;
+  pTerm->iParent = -1;
+  memset(&pTerm->eOperator, 0,
+         sizeof(WhereTerm) - offsetof(WhereTerm,eOperator));
+  return idx;
+}
+
+/*
+** Return TRUE if the given operator is one of the operators that is
+** allowed for an indexable WHERE clause term.  The allowed operators are
+** "=", "<", ">", "<=", ">=", "IN", "IS", and "IS NULL"
+*/
+static int allowedOp(int op){
+  assert( TK_GT>TK_EQ && TK_GT<TK_GE );
+  assert( TK_LT>TK_EQ && TK_LT<TK_GE );
+  assert( TK_LE>TK_EQ && TK_LE<TK_GE );
+  assert( TK_GE==TK_EQ+4 );
+  assert( TK_IN<TK_EQ );
+  assert( TK_IS<TK_EQ );
+  assert( TK_ISNULL<TK_EQ );
+  if( op>TK_GE ) return 0;
+  if( op>=TK_EQ ) return 1;
+  return op==TK_IN || op==TK_ISNULL || op==TK_IS;
+}
+
+/*
+** Commute a comparison operator.  Expressions of the form "X op Y"
+** are converted into "Y op X".
+*/
+static u16 exprCommute(Parse *pParse, Expr *pExpr){
+  if( pExpr->pLeft->op==TK_VECTOR
+   || pExpr->pRight->op==TK_VECTOR
+   || sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft, pExpr->pRight) !=
+      sqlite3BinaryCompareCollSeq(pParse, pExpr->pRight, pExpr->pLeft)
+  ){
+    pExpr->flags ^= EP_Commuted;
+  }
+  SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
+  if( pExpr->op>=TK_GT ){
+    assert( TK_LT==TK_GT+2 );
+    assert( TK_GE==TK_LE+2 );
+    assert( TK_GT>TK_EQ );
+    assert( TK_GT<TK_LE );
+    assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
+    pExpr->op = ((pExpr->op-TK_GT)^2)+TK_GT;
+  }
+  return 0;
+}
+
+/*
+** Translate from TK_xx operator to WO_xx bitmask.
+*/
+static u16 operatorMask(int op){
+  u16 c;
+  assert( allowedOp(op) );
+  if( op>=TK_EQ ){
+    assert( (WO_EQ<<(op-TK_EQ)) < 0x7fff );
+    c = (u16)(WO_EQ<<(op-TK_EQ));
+  }else if( op==TK_IN ){
+    c = WO_IN;
+  }else if( op==TK_ISNULL ){
+    c = WO_ISNULL;
+  }else{
+    assert( op==TK_IS );
+    c = WO_IS;
+  }
+  assert( op!=TK_ISNULL || c==WO_ISNULL );
+  assert( op!=TK_IN || c==WO_IN );
+  assert( op!=TK_EQ || c==WO_EQ );
+  assert( op!=TK_LT || c==WO_LT );
+  assert( op!=TK_LE || c==WO_LE );
+  assert( op!=TK_GT || c==WO_GT );
+  assert( op!=TK_GE || c==WO_GE );
+  assert( op!=TK_IS || c==WO_IS );
+  return c;
+}
+
+
+#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
+/*
+** Check to see if the given expression is a LIKE or GLOB operator that
+** can be optimized using inequality constraints.  Return TRUE if it is
+** so and false if not.
+**
+** In order for the operator to be optimizible, the RHS must be a string
+** literal that does not begin with a wildcard.  The LHS must be a column
+** that may only be NULL, a string, or a BLOB, never a number. (This means
+** that virtual tables cannot participate in the LIKE optimization.)  The
+** collating sequence for the column on the LHS must be appropriate for
+** the operator.
+*/
+static int isLikeOrGlob(
+  Parse *pParse,    /* Parsing and code generating context */
+  Expr *pExpr,      /* Test this expression */
+  Expr **ppPrefix,  /* Pointer to TK_STRING expression with pattern prefix */
+  int *pisComplete, /* True if the only wildcard is % in the last character */
+  int *pnoCase      /* True if uppercase is equivalent to lowercase */
+){
+  const u8 *z = 0;           /* String on RHS of LIKE operator */
+  Expr *pRight, *pLeft;      /* Right and left size of LIKE operator */
+  ExprList *pList;           /* List of operands to the LIKE operator */
+  u8 c;                      /* One character in z[] */
+  int cnt;                   /* Number of non-wildcard prefix characters */
+  u8 wc[4];                  /* Wildcard characters */
+  sqlite3 *db = pParse->db;  /* Database connection */
+  sqlite3_value *pVal = 0;
+  int op;                    /* Opcode of pRight */
+  int rc;                    /* Result code to return */
+
+  if( !sqlite3IsLikeFunction(db, pExpr, pnoCase, (char*)wc) ){
+    return 0;
+  }
+#ifdef SQLITE_EBCDIC
+  if( *pnoCase ) return 0;
+#endif
+  assert( ExprUseXList(pExpr) );
+  pList = pExpr->x.pList;
+  pLeft = pList->a[1].pExpr;
+
+  pRight = sqlite3ExprSkipCollate(pList->a[0].pExpr);
+  op = pRight->op;
+  if( op==TK_VARIABLE && (db->flags & SQLITE_EnableQPSG)==0 ){
+    Vdbe *pReprepare = pParse->pReprepare;
+    int iCol = pRight->iColumn;
+    pVal = sqlite3VdbeGetBoundValue(pReprepare, iCol, SQLITE_AFF_BLOB);
+    if( pVal && sqlite3_value_type(pVal)==SQLITE_TEXT ){
+      z = sqlite3_value_text(pVal);
+    }
+    sqlite3VdbeSetVarmask(pParse->pVdbe, iCol);
+    assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER );
+  }else if( op==TK_STRING ){
+    assert( !ExprHasProperty(pRight, EP_IntValue) );
+     z = (u8*)pRight->u.zToken;
+  }
+  if( z ){
+    /* Count the number of prefix bytes prior to the first wildcard,
+    ** U+fffd character, or malformed utf-8. If the underlying database
+    ** has a UTF16LE encoding, then only consider ASCII characters.  Note that
+    ** the encoding of z[] is UTF8 - we are dealing with only UTF8 here in this
+    ** code, but the database engine itself might be processing content using a
+    ** different encoding. */
+    cnt = 0;
+    while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){
+      cnt++;
+      if( c==wc[3] && z[cnt]>0 && z[cnt]<0x80 ){
+        cnt++;
+      }else if( c>=0x80 ){
+        const u8 *z2 = z+cnt-1;
+        if( c==0xff || sqlite3Utf8Read(&z2)==0xfffd  /* bad utf-8 */
+         || ENC(db)==SQLITE_UTF16LE
+        ){
+          cnt--;
+          break;
+        }else{
+          cnt = (int)(z2-z);
+        }
+      }
+    }
+
+    /* The optimization is possible only if (1) the pattern does not begin
+    ** with a wildcard and if (2) the non-wildcard prefix does not end with
+    ** an (illegal 0xff) character, or (3) the pattern does not consist of
+    ** a single escape character. The second condition is necessary so
+    ** that we can increment the prefix key to find an upper bound for the
+    ** range search. The third is because the caller assumes that the pattern
+    ** consists of at least one character after all escapes have been
+    ** removed.  */
+    if( (cnt>1 || (cnt>0 && z[0]!=wc[3])) && ALWAYS(255!=(u8)z[cnt-1]) ){
+      Expr *pPrefix;
+
+      /* A "complete" match if the pattern ends with "*" or "%" */
+      *pisComplete = c==wc[0] && z[cnt+1]==0 && ENC(db)!=SQLITE_UTF16LE;
+
+      /* Get the pattern prefix.  Remove all escapes from the prefix. */
+      pPrefix = sqlite3Expr(db, TK_STRING, (char*)z);
+      if( pPrefix ){
+        int iFrom, iTo;
+        char *zNew;
+        assert( !ExprHasProperty(pPrefix, EP_IntValue) );
+        zNew = pPrefix->u.zToken;
+        zNew[cnt] = 0;
+        for(iFrom=iTo=0; iFrom<cnt; iFrom++){
+          if( zNew[iFrom]==wc[3] ) iFrom++;
+          zNew[iTo++] = zNew[iFrom];
+        }
+        zNew[iTo] = 0;
+        assert( iTo>0 );
+
+        /* If the LHS is not an ordinary column with TEXT affinity, then the
+        ** pattern prefix boundaries (both the start and end boundaries) must
+        ** not look like a number.  Otherwise the pattern might be treated as
+        ** a number, which will invalidate the LIKE optimization.
+        **
+        ** Getting this right has been a persistent source of bugs in the
+        ** LIKE optimization.  See, for example:
+        **    2018-09-10 https://sqlite.org/src/info/c94369cae9b561b1
+        **    2019-05-02 https://sqlite.org/src/info/b043a54c3de54b28
+        **    2019-06-10 https://sqlite.org/src/info/fd76310a5e843e07
+        **    2019-06-14 https://sqlite.org/src/info/ce8717f0885af975
+        **    2019-09-03 https://sqlite.org/src/info/0f0428096f17252a
+        */
+        if( pLeft->op!=TK_COLUMN
+         || sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT
+         || (ALWAYS( ExprUseYTab(pLeft) )
+             && ALWAYS(pLeft->y.pTab)
+             && IsVirtual(pLeft->y.pTab))  /* Might be numeric */
+        ){
+          int isNum;
+          double rDummy;
+          isNum = sqlite3AtoF(zNew, &rDummy, iTo, SQLITE_UTF8);
+          if( isNum<=0 ){
+            if( iTo==1 && zNew[0]=='-' ){
+              isNum = +1;
+            }else{
+              zNew[iTo-1]++;
+              isNum = sqlite3AtoF(zNew, &rDummy, iTo, SQLITE_UTF8);
+              zNew[iTo-1]--;
+            }
+          }
+          if( isNum>0 ){
+            sqlite3ExprDelete(db, pPrefix);
+            sqlite3ValueFree(pVal);
+            return 0;
+          }
+        }
+      }
+      *ppPrefix = pPrefix;
+
+      /* If the RHS pattern is a bound parameter, make arrangements to
+      ** reprepare the statement when that parameter is rebound */
+      if( op==TK_VARIABLE ){
+        Vdbe *v = pParse->pVdbe;
+        sqlite3VdbeSetVarmask(v, pRight->iColumn);
+        assert( !ExprHasProperty(pRight, EP_IntValue) );
+        if( *pisComplete && pRight->u.zToken[1] ){
+          /* If the rhs of the LIKE expression is a variable, and the current
+          ** value of the variable means there is no need to invoke the LIKE
+          ** function, then no OP_Variable will be added to the program.
+          ** This causes problems for the sqlite3_bind_parameter_name()
+          ** API. To work around them, add a dummy OP_Variable here.
+          */
+          int r1 = sqlite3GetTempReg(pParse);
+          sqlite3ExprCodeTarget(pParse, pRight, r1);
+          sqlite3VdbeChangeP3(v, sqlite3VdbeCurrentAddr(v)-1, 0);
+          sqlite3ReleaseTempReg(pParse, r1);
+        }
+      }
+    }else{
+      z = 0;
+    }
+  }
+
+  rc = (z!=0);
+  sqlite3ValueFree(pVal);
+  return rc;
+}
+#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Check to see if the pExpr expression is a form that needs to be passed
+** to the xBestIndex method of virtual tables.  Forms of interest include:
+**
+**          Expression                   Virtual Table Operator
+**          -----------------------      ---------------------------------
+**      1.  column MATCH expr            SQLITE_INDEX_CONSTRAINT_MATCH
+**      2.  column GLOB expr             SQLITE_INDEX_CONSTRAINT_GLOB
+**      3.  column LIKE expr             SQLITE_INDEX_CONSTRAINT_LIKE
+**      4.  column REGEXP expr           SQLITE_INDEX_CONSTRAINT_REGEXP
+**      5.  column != expr               SQLITE_INDEX_CONSTRAINT_NE
+**      6.  expr != column               SQLITE_INDEX_CONSTRAINT_NE
+**      7.  column IS NOT expr           SQLITE_INDEX_CONSTRAINT_ISNOT
+**      8.  expr IS NOT column           SQLITE_INDEX_CONSTRAINT_ISNOT
+**      9.  column IS NOT NULL           SQLITE_INDEX_CONSTRAINT_ISNOTNULL
+**
+** In every case, "column" must be a column of a virtual table.  If there
+** is a match, set *ppLeft to the "column" expression, set *ppRight to the
+** "expr" expression (even though in forms (6) and (8) the column is on the
+** right and the expression is on the left).  Also set *peOp2 to the
+** appropriate virtual table operator.  The return value is 1 or 2 if there
+** is a match.  The usual return is 1, but if the RHS is also a column
+** of virtual table in forms (5) or (7) then return 2.
+**
+** If the expression matches none of the patterns above, return 0.
+*/
+static int isAuxiliaryVtabOperator(
+  sqlite3 *db,                    /* Parsing context */
+  Expr *pExpr,                    /* Test this expression */
+  unsigned char *peOp2,           /* OUT: 0 for MATCH, or else an op2 value */
+  Expr **ppLeft,                  /* Column expression to left of MATCH/op2 */
+  Expr **ppRight                  /* Expression to left of MATCH/op2 */
+){
+  if( pExpr->op==TK_FUNCTION ){
+    static const struct Op2 {
+      const char *zOp;
+      unsigned char eOp2;
+    } aOp[] = {
+      { "match",  SQLITE_INDEX_CONSTRAINT_MATCH },
+      { "glob",   SQLITE_INDEX_CONSTRAINT_GLOB },
+      { "like",   SQLITE_INDEX_CONSTRAINT_LIKE },
+      { "regexp", SQLITE_INDEX_CONSTRAINT_REGEXP }
+    };
+    ExprList *pList;
+    Expr *pCol;                     /* Column reference */
+    int i;
+
+    assert( ExprUseXList(pExpr) );
+    pList = pExpr->x.pList;
+    if( pList==0 || pList->nExpr!=2 ){
+      return 0;
+    }
+
+    /* Built-in operators MATCH, GLOB, LIKE, and REGEXP attach to a
+    ** virtual table on their second argument, which is the same as
+    ** the left-hand side operand in their in-fix form.
+    **
+    **       vtab_column MATCH expression
+    **       MATCH(expression,vtab_column)
+    */
+    pCol = pList->a[1].pExpr;
+    assert( pCol->op!=TK_COLUMN || (ExprUseYTab(pCol) && pCol->y.pTab!=0) );
+    if( ExprIsVtab(pCol) ){
+      for(i=0; i<ArraySize(aOp); i++){
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        if( sqlite3StrICmp(pExpr->u.zToken, aOp[i].zOp)==0 ){
+          *peOp2 = aOp[i].eOp2;
+          *ppRight = pList->a[0].pExpr;
+          *ppLeft = pCol;
+          return 1;
+        }
+      }
+    }
+
+    /* We can also match against the first column of overloaded
+    ** functions where xFindFunction returns a value of at least
+    ** SQLITE_INDEX_CONSTRAINT_FUNCTION.
+    **
+    **      OVERLOADED(vtab_column,expression)
+    **
+    ** Historically, xFindFunction expected to see lower-case function
+    ** names.  But for this use case, xFindFunction is expected to deal
+    ** with function names in an arbitrary case.
+    */
+    pCol = pList->a[0].pExpr;
+    assert( pCol->op!=TK_COLUMN || ExprUseYTab(pCol) );
+    assert( pCol->op!=TK_COLUMN || (ExprUseYTab(pCol) && pCol->y.pTab!=0) );
+    if( ExprIsVtab(pCol) ){
+      sqlite3_vtab *pVtab;
+      sqlite3_module *pMod;
+      void (*xNotUsed)(sqlite3_context*,int,sqlite3_value**);
+      void *pNotUsed;
+      pVtab = sqlite3GetVTable(db, pCol->y.pTab)->pVtab;
+      assert( pVtab!=0 );
+      assert( pVtab->pModule!=0 );
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      pMod = (sqlite3_module *)pVtab->pModule;
+      if( pMod->xFindFunction!=0 ){
+        i = pMod->xFindFunction(pVtab,2, pExpr->u.zToken, &xNotUsed, &pNotUsed);
+        if( i>=SQLITE_INDEX_CONSTRAINT_FUNCTION ){
+          *peOp2 = i;
+          *ppRight = pList->a[1].pExpr;
+          *ppLeft = pCol;
+          return 1;
+        }
+      }
+    }
+  }else if( pExpr->op>=TK_EQ ){
+    /* Comparison operators are a common case.  Save a few comparisons for
+    ** that common case by terminating early. */
+    assert( TK_NE < TK_EQ );
+    assert( TK_ISNOT < TK_EQ );
+    assert( TK_NOTNULL < TK_EQ );
+    return 0;
+  }else if( pExpr->op==TK_NE || pExpr->op==TK_ISNOT || pExpr->op==TK_NOTNULL ){
+    int res = 0;
+    Expr *pLeft = pExpr->pLeft;
+    Expr *pRight = pExpr->pRight;
+    assert( pLeft->op!=TK_COLUMN || (ExprUseYTab(pLeft) && pLeft->y.pTab!=0) );
+    if( ExprIsVtab(pLeft) ){
+      res++;
+    }
+    assert( pRight==0 || pRight->op!=TK_COLUMN
+            || (ExprUseYTab(pRight) && pRight->y.pTab!=0) );
+    if( pRight && ExprIsVtab(pRight) ){
+      res++;
+      SWAP(Expr*, pLeft, pRight);
+    }
+    *ppLeft = pLeft;
+    *ppRight = pRight;
+    if( pExpr->op==TK_NE ) *peOp2 = SQLITE_INDEX_CONSTRAINT_NE;
+    if( pExpr->op==TK_ISNOT ) *peOp2 = SQLITE_INDEX_CONSTRAINT_ISNOT;
+    if( pExpr->op==TK_NOTNULL ) *peOp2 = SQLITE_INDEX_CONSTRAINT_ISNOTNULL;
+    return res;
+  }
+  return 0;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** If the pBase expression originated in the ON or USING clause of
+** a join, then transfer the appropriate markings over to derived.
+*/
+static void transferJoinMarkings(Expr *pDerived, Expr *pBase){
+  if( pDerived && ExprHasProperty(pBase, EP_OuterON|EP_InnerON) ){
+    pDerived->flags |= pBase->flags & (EP_OuterON|EP_InnerON);
+    pDerived->w.iJoin = pBase->w.iJoin;
+  }
+}
+
+/*
+** Mark term iChild as being a child of term iParent
+*/
+static void markTermAsChild(WhereClause *pWC, int iChild, int iParent){
+  pWC->a[iChild].iParent = iParent;
+  pWC->a[iChild].truthProb = pWC->a[iParent].truthProb;
+  pWC->a[iParent].nChild++;
+}
+
+/*
+** Return the N-th AND-connected subterm of pTerm.  Or if pTerm is not
+** a conjunction, then return just pTerm when N==0.  If N is exceeds
+** the number of available subterms, return NULL.
+*/
+static WhereTerm *whereNthSubterm(WhereTerm *pTerm, int N){
+  if( pTerm->eOperator!=WO_AND ){
+    return N==0 ? pTerm : 0;
+  }
+  if( N<pTerm->u.pAndInfo->wc.nTerm ){
+    return &pTerm->u.pAndInfo->wc.a[N];
+  }
+  return 0;
+}
+
+/*
+** Subterms pOne and pTwo are contained within WHERE clause pWC.  The
+** two subterms are in disjunction - they are OR-ed together.
+**
+** If these two terms are both of the form:  "A op B" with the same
+** A and B values but different operators and if the operators are
+** compatible (if one is = and the other is <, for example) then
+** add a new virtual AND term to pWC that is the combination of the
+** two.
+**
+** Some examples:
+**
+**    x<y OR x=y    -->     x<=y
+**    x=y OR x=y    -->     x=y
+**    x<=y OR x<y   -->     x<=y
+**
+** The following is NOT generated:
+**
+**    x<y OR x>y    -->     x!=y
+*/
+static void whereCombineDisjuncts(
+  SrcList *pSrc,         /* the FROM clause */
+  WhereClause *pWC,      /* The complete WHERE clause */
+  WhereTerm *pOne,       /* First disjunct */
+  WhereTerm *pTwo        /* Second disjunct */
+){
+  u16 eOp = pOne->eOperator | pTwo->eOperator;
+  sqlite3 *db;           /* Database connection (for malloc) */
+  Expr *pNew;            /* New virtual expression */
+  int op;                /* Operator for the combined expression */
+  int idxNew;            /* Index in pWC of the next virtual term */
+
+  if( (pOne->wtFlags | pTwo->wtFlags) & TERM_VNULL ) return;
+  if( (pOne->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE))==0 ) return;
+  if( (pTwo->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE))==0 ) return;
+  if( (eOp & (WO_EQ|WO_LT|WO_LE))!=eOp
+   && (eOp & (WO_EQ|WO_GT|WO_GE))!=eOp ) return;
+  assert( pOne->pExpr->pLeft!=0 && pOne->pExpr->pRight!=0 );
+  assert( pTwo->pExpr->pLeft!=0 && pTwo->pExpr->pRight!=0 );
+  if( sqlite3ExprCompare(0,pOne->pExpr->pLeft, pTwo->pExpr->pLeft, -1) ) return;
+  if( sqlite3ExprCompare(0,pOne->pExpr->pRight, pTwo->pExpr->pRight,-1) )return;
+  /* If we reach this point, it means the two subterms can be combined */
+  if( (eOp & (eOp-1))!=0 ){
+    if( eOp & (WO_LT|WO_LE) ){
+      eOp = WO_LE;
+    }else{
+      assert( eOp & (WO_GT|WO_GE) );
+      eOp = WO_GE;
+    }
+  }
+  db = pWC->pWInfo->pParse->db;
+  pNew = sqlite3ExprDup(db, pOne->pExpr, 0);
+  if( pNew==0 ) return;
+  for(op=TK_EQ; eOp!=(WO_EQ<<(op-TK_EQ)); op++){ assert( op<TK_GE ); }
+  pNew->op = op;
+  idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
+  exprAnalyze(pSrc, pWC, idxNew);
+}
+
+#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
+/*
+** Analyze a term that consists of two or more OR-connected
+** subterms.  So in:
+**
+**     ... WHERE  (a=5) AND (b=7 OR c=9 OR d=13) AND (d=13)
+**                          ^^^^^^^^^^^^^^^^^^^^
+**
+** This routine analyzes terms such as the middle term in the above example.
+** A WhereOrTerm object is computed and attached to the term under
+** analysis, regardless of the outcome of the analysis.  Hence:
+**
+**     WhereTerm.wtFlags   |=  TERM_ORINFO
+**     WhereTerm.u.pOrInfo  =  a dynamically allocated WhereOrTerm object
+**
+** The term being analyzed must have two or more of OR-connected subterms.
+** A single subterm might be a set of AND-connected sub-subterms.
+** Examples of terms under analysis:
+**
+**     (A)     t1.x=t2.y OR t1.x=t2.z OR t1.y=15 OR t1.z=t3.a+5
+**     (B)     x=expr1 OR expr2=x OR x=expr3
+**     (C)     t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
+**     (D)     x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
+**     (E)     (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
+**     (F)     x>A OR (x=A AND y>=B)
+**
+** CASE 1:
+**
+** If all subterms are of the form T.C=expr for some single column of C and
+** a single table T (as shown in example B above) then create a new virtual
+** term that is an equivalent IN expression.  In other words, if the term
+** being analyzed is:
+**
+**      x = expr1  OR  expr2 = x  OR  x = expr3
+**
+** then create a new virtual term like this:
+**
+**      x IN (expr1,expr2,expr3)
+**
+** CASE 2:
+**
+** If there are exactly two disjuncts and one side has x>A and the other side
+** has x=A (for the same x and A) then add a new virtual conjunct term to the
+** WHERE clause of the form "x>=A".  Example:
+**
+**      x>A OR (x=A AND y>B)    adds:    x>=A
+**
+** The added conjunct can sometimes be helpful in query planning.
+**
+** CASE 3:
+**
+** If all subterms are indexable by a single table T, then set
+**
+**     WhereTerm.eOperator              =  WO_OR
+**     WhereTerm.u.pOrInfo->indexable  |=  the cursor number for table T
+**
+** A subterm is "indexable" if it is of the form
+** "T.C <op> <expr>" where C is any column of table T and
+** <op> is one of "=", "<", "<=", ">", ">=", "IS NULL", or "IN".
+** A subterm is also indexable if it is an AND of two or more
+** subsubterms at least one of which is indexable.  Indexable AND
+** subterms have their eOperator set to WO_AND and they have
+** u.pAndInfo set to a dynamically allocated WhereAndTerm object.
+**
+** From another point of view, "indexable" means that the subterm could
+** potentially be used with an index if an appropriate index exists.
+** This analysis does not consider whether or not the index exists; that
+** is decided elsewhere.  This analysis only looks at whether subterms
+** appropriate for indexing exist.
+**
+** All examples A through E above satisfy case 3.  But if a term
+** also satisfies case 1 (such as B) we know that the optimizer will
+** always prefer case 1, so in that case we pretend that case 3 is not
+** satisfied.
+**
+** It might be the case that multiple tables are indexable.  For example,
+** (E) above is indexable on tables P, Q, and R.
+**
+** Terms that satisfy case 3 are candidates for lookup by using
+** separate indices to find rowids for each subterm and composing
+** the union of all rowids using a RowSet object.  This is similar
+** to "bitmap indices" in other database engines.
+**
+** OTHERWISE:
+**
+** If none of cases 1, 2, or 3 apply, then leave the eOperator set to
+** zero.  This term is not useful for search.
+*/
+static void exprAnalyzeOrTerm(
+  SrcList *pSrc,            /* the FROM clause */
+  WhereClause *pWC,         /* the complete WHERE clause */
+  int idxTerm               /* Index of the OR-term to be analyzed */
+){
+  WhereInfo *pWInfo = pWC->pWInfo;        /* WHERE clause processing context */
+  Parse *pParse = pWInfo->pParse;         /* Parser context */
+  sqlite3 *db = pParse->db;               /* Database connection */
+  WhereTerm *pTerm = &pWC->a[idxTerm];    /* The term to be analyzed */
+  Expr *pExpr = pTerm->pExpr;             /* The expression of the term */
+  int i;                                  /* Loop counters */
+  WhereClause *pOrWc;       /* Breakup of pTerm into subterms */
+  WhereTerm *pOrTerm;       /* A Sub-term within the pOrWc */
+  WhereOrInfo *pOrInfo;     /* Additional information associated with pTerm */
+  Bitmask chngToIN;         /* Tables that might satisfy case 1 */
+  Bitmask indexable;        /* Tables that are indexable, satisfying case 2 */
+
+  /*
+  ** Break the OR clause into its separate subterms.  The subterms are
+  ** stored in a WhereClause structure containing within the WhereOrInfo
+  ** object that is attached to the original OR clause term.
+  */
+  assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
+  assert( pExpr->op==TK_OR );
+  pTerm->u.pOrInfo = pOrInfo = sqlite3DbMallocZero(db, sizeof(*pOrInfo));
+  if( pOrInfo==0 ) return;
+  pTerm->wtFlags |= TERM_ORINFO;
+  pOrWc = &pOrInfo->wc;
+  memset(pOrWc->aStatic, 0, sizeof(pOrWc->aStatic));
+  sqlite3WhereClauseInit(pOrWc, pWInfo);
+  sqlite3WhereSplit(pOrWc, pExpr, TK_OR);
+  sqlite3WhereExprAnalyze(pSrc, pOrWc);
+  if( db->mallocFailed ) return;
+  assert( pOrWc->nTerm>=2 );
+
+  /*
+  ** Compute the set of tables that might satisfy cases 1 or 3.
+  */
+  indexable = ~(Bitmask)0;
+  chngToIN = ~(Bitmask)0;
+  for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
+    if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
+      WhereAndInfo *pAndInfo;
+      assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 );
+      chngToIN = 0;
+      pAndInfo = sqlite3DbMallocRawNN(db, sizeof(*pAndInfo));
+      if( pAndInfo ){
+        WhereClause *pAndWC;
+        WhereTerm *pAndTerm;
+        int j;
+        Bitmask b = 0;
+        pOrTerm->u.pAndInfo = pAndInfo;
+        pOrTerm->wtFlags |= TERM_ANDINFO;
+        pOrTerm->eOperator = WO_AND;
+        pOrTerm->leftCursor = -1;
+        pAndWC = &pAndInfo->wc;
+        memset(pAndWC->aStatic, 0, sizeof(pAndWC->aStatic));
+        sqlite3WhereClauseInit(pAndWC, pWC->pWInfo);
+        sqlite3WhereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
+        sqlite3WhereExprAnalyze(pSrc, pAndWC);
+        pAndWC->pOuter = pWC;
+        if( !db->mallocFailed ){
+          for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
+            assert( pAndTerm->pExpr );
+            if( allowedOp(pAndTerm->pExpr->op)
+             || pAndTerm->eOperator==WO_AUX
+            ){
+              b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pAndTerm->leftCursor);
+            }
+          }
+        }
+        indexable &= b;
+      }
+    }else if( pOrTerm->wtFlags & TERM_COPIED ){
+      /* Skip this term for now.  We revisit it when we process the
+      ** corresponding TERM_VIRTUAL term */
+    }else{
+      Bitmask b;
+      b = sqlite3WhereGetMask(&pWInfo->sMaskSet, pOrTerm->leftCursor);
+      if( pOrTerm->wtFlags & TERM_VIRTUAL ){
+        WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent];
+        b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pOther->leftCursor);
+      }
+      indexable &= b;
+      if( (pOrTerm->eOperator & WO_EQ)==0 ){
+        chngToIN = 0;
+      }else{
+        chngToIN &= b;
+      }
+    }
+  }
+
+  /*
+  ** Record the set of tables that satisfy case 3.  The set might be
+  ** empty.
+  */
+  pOrInfo->indexable = indexable;
+  pTerm->eOperator = WO_OR;
+  pTerm->leftCursor = -1;
+  if( indexable ){
+    pWC->hasOr = 1;
+  }
+
+  /* For a two-way OR, attempt to implementation case 2.
+  */
+  if( indexable && pOrWc->nTerm==2 ){
+    int iOne = 0;
+    WhereTerm *pOne;
+    while( (pOne = whereNthSubterm(&pOrWc->a[0],iOne++))!=0 ){
+      int iTwo = 0;
+      WhereTerm *pTwo;
+      while( (pTwo = whereNthSubterm(&pOrWc->a[1],iTwo++))!=0 ){
+        whereCombineDisjuncts(pSrc, pWC, pOne, pTwo);
+      }
+    }
+  }
+
+  /*
+  ** chngToIN holds a set of tables that *might* satisfy case 1.  But
+  ** we have to do some additional checking to see if case 1 really
+  ** is satisfied.
+  **
+  ** chngToIN will hold either 0, 1, or 2 bits.  The 0-bit case means
+  ** that there is no possibility of transforming the OR clause into an
+  ** IN operator because one or more terms in the OR clause contain
+  ** something other than == on a column in the single table.  The 1-bit
+  ** case means that every term of the OR clause is of the form
+  ** "table.column=expr" for some single table.  The one bit that is set
+  ** will correspond to the common table.  We still need to check to make
+  ** sure the same column is used on all terms.  The 2-bit case is when
+  ** the all terms are of the form "table1.column=table2.column".  It
+  ** might be possible to form an IN operator with either table1.column
+  ** or table2.column as the LHS if either is common to every term of
+  ** the OR clause.
+  **
+  ** Note that terms of the form "table.column1=table.column2" (the
+  ** same table on both sizes of the ==) cannot be optimized.
+  */
+  if( chngToIN ){
+    int okToChngToIN = 0;     /* True if the conversion to IN is valid */
+    int iColumn = -1;         /* Column index on lhs of IN operator */
+    int iCursor = -1;         /* Table cursor common to all terms */
+    int j = 0;                /* Loop counter */
+
+    /* Search for a table and column that appears on one side or the
+    ** other of the == operator in every subterm.  That table and column
+    ** will be recorded in iCursor and iColumn.  There might not be any
+    ** such table and column.  Set okToChngToIN if an appropriate table
+    ** and column is found but leave okToChngToIN false if not found.
+    */
+    for(j=0; j<2 && !okToChngToIN; j++){
+      Expr *pLeft = 0;
+      pOrTerm = pOrWc->a;
+      for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
+        assert( pOrTerm->eOperator & WO_EQ );
+        pOrTerm->wtFlags &= ~TERM_OK;
+        if( pOrTerm->leftCursor==iCursor ){
+          /* This is the 2-bit case and we are on the second iteration and
+          ** current term is from the first iteration.  So skip this term. */
+          assert( j==1 );
+          continue;
+        }
+        if( (chngToIN & sqlite3WhereGetMask(&pWInfo->sMaskSet,
+                                            pOrTerm->leftCursor))==0 ){
+          /* This term must be of the form t1.a==t2.b where t2 is in the
+          ** chngToIN set but t1 is not.  This term will be either preceded
+          ** or followed by an inverted copy (t2.b==t1.a).  Skip this term
+          ** and use its inversion. */
+          testcase( pOrTerm->wtFlags & TERM_COPIED );
+          testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
+          assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
+          continue;
+        }
+        assert( (pOrTerm->eOperator & (WO_OR|WO_AND))==0 );
+        iColumn = pOrTerm->u.x.leftColumn;
+        iCursor = pOrTerm->leftCursor;
+        pLeft = pOrTerm->pExpr->pLeft;
+        break;
+      }
+      if( i<0 ){
+        /* No candidate table+column was found.  This can only occur
+        ** on the second iteration */
+        assert( j==1 );
+        assert( IsPowerOfTwo(chngToIN) );
+        assert( chngToIN==sqlite3WhereGetMask(&pWInfo->sMaskSet, iCursor) );
+        break;
+      }
+      testcase( j==1 );
+
+      /* We have found a candidate table and column.  Check to see if that
+      ** table and column is common to every term in the OR clause */
+      okToChngToIN = 1;
+      for(; i>=0 && okToChngToIN; i--, pOrTerm++){
+        assert( pOrTerm->eOperator & WO_EQ );
+        assert( (pOrTerm->eOperator & (WO_OR|WO_AND))==0 );
+        if( pOrTerm->leftCursor!=iCursor ){
+          pOrTerm->wtFlags &= ~TERM_OK;
+        }else if( pOrTerm->u.x.leftColumn!=iColumn || (iColumn==XN_EXPR
+               && sqlite3ExprCompare(pParse, pOrTerm->pExpr->pLeft, pLeft, -1)
+        )){
+          okToChngToIN = 0;
+        }else{
+          int affLeft, affRight;
+          /* If the right-hand side is also a column, then the affinities
+          ** of both right and left sides must be such that no type
+          ** conversions are required on the right.  (Ticket #2249)
+          */
+          affRight = sqlite3ExprAffinity(pOrTerm->pExpr->pRight);
+          affLeft = sqlite3ExprAffinity(pOrTerm->pExpr->pLeft);
+          if( affRight!=0 && affRight!=affLeft ){
+            okToChngToIN = 0;
+          }else{
+            pOrTerm->wtFlags |= TERM_OK;
+          }
+        }
+      }
+    }
+
+    /* At this point, okToChngToIN is true if original pTerm satisfies
+    ** case 1.  In that case, construct a new virtual term that is
+    ** pTerm converted into an IN operator.
+    */
+    if( okToChngToIN ){
+      Expr *pDup;            /* A transient duplicate expression */
+      ExprList *pList = 0;   /* The RHS of the IN operator */
+      Expr *pLeft = 0;       /* The LHS of the IN operator */
+      Expr *pNew;            /* The complete IN operator */
+
+      for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){
+        if( (pOrTerm->wtFlags & TERM_OK)==0 ) continue;
+        assert( pOrTerm->eOperator & WO_EQ );
+        assert( (pOrTerm->eOperator & (WO_OR|WO_AND))==0 );
+        assert( pOrTerm->leftCursor==iCursor );
+        assert( pOrTerm->u.x.leftColumn==iColumn );
+        pDup = sqlite3ExprDup(db, pOrTerm->pExpr->pRight, 0);
+        pList = sqlite3ExprListAppend(pWInfo->pParse, pList, pDup);
+        pLeft = pOrTerm->pExpr->pLeft;
+      }
+      assert( pLeft!=0 );
+      pDup = sqlite3ExprDup(db, pLeft, 0);
+      pNew = sqlite3PExpr(pParse, TK_IN, pDup, 0);
+      if( pNew ){
+        int idxNew;
+        transferJoinMarkings(pNew, pExpr);
+        assert( ExprUseXList(pNew) );
+        pNew->x.pList = pList;
+        idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
+        testcase( idxNew==0 );
+        exprAnalyze(pSrc, pWC, idxNew);
+        /* pTerm = &pWC->a[idxTerm]; // would be needed if pTerm where reused */
+        markTermAsChild(pWC, idxNew, idxTerm);
+      }else{
+        sqlite3ExprListDelete(db, pList);
+      }
+    }
+  }
+}
+#endif /* !SQLITE_OMIT_OR_OPTIMIZATION && !SQLITE_OMIT_SUBQUERY */
+
+/*
+** We already know that pExpr is a binary operator where both operands are
+** column references.  This routine checks to see if pExpr is an equivalence
+** relation:
+**   1.  The SQLITE_Transitive optimization must be enabled
+**   2.  Must be either an == or an IS operator
+**   3.  Not originating in the ON clause of an OUTER JOIN
+**   4.  The affinities of A and B must be compatible
+**   5a. Both operands use the same collating sequence OR
+**   5b. The overall collating sequence is BINARY
+** If this routine returns TRUE, that means that the RHS can be substituted
+** for the LHS anyplace else in the WHERE clause where the LHS column occurs.
+** This is an optimization.  No harm comes from returning 0.  But if 1 is
+** returned when it should not be, then incorrect answers might result.
+*/
+static int termIsEquivalence(Parse *pParse, Expr *pExpr){
+  char aff1, aff2;
+  CollSeq *pColl;
+  if( !OptimizationEnabled(pParse->db, SQLITE_Transitive) ) return 0;
+  if( pExpr->op!=TK_EQ && pExpr->op!=TK_IS ) return 0;
+  if( ExprHasProperty(pExpr, EP_OuterON) ) return 0;
+  aff1 = sqlite3ExprAffinity(pExpr->pLeft);
+  aff2 = sqlite3ExprAffinity(pExpr->pRight);
+  if( aff1!=aff2
+   && (!sqlite3IsNumericAffinity(aff1) || !sqlite3IsNumericAffinity(aff2))
+  ){
+    return 0;
+  }
+  pColl = sqlite3ExprCompareCollSeq(pParse, pExpr);
+  if( sqlite3IsBinary(pColl) ) return 1;
+  return sqlite3ExprCollSeqMatch(pParse, pExpr->pLeft, pExpr->pRight);
+}
+
+/*
+** Recursively walk the expressions of a SELECT statement and generate
+** a bitmask indicating which tables are used in that expression
+** tree.
+*/
+static Bitmask exprSelectUsage(WhereMaskSet *pMaskSet, Select *pS){
+  Bitmask mask = 0;
+  while( pS ){
+    SrcList *pSrc = pS->pSrc;
+    mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pEList);
+    mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pGroupBy);
+    mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pOrderBy);
+    mask |= sqlite3WhereExprUsage(pMaskSet, pS->pWhere);
+    mask |= sqlite3WhereExprUsage(pMaskSet, pS->pHaving);
+    if( ALWAYS(pSrc!=0) ){
+      int i;
+      for(i=0; i<pSrc->nSrc; i++){
+        if( pSrc->a[i].fg.isSubquery ){
+          mask |= exprSelectUsage(pMaskSet, pSrc->a[i].u4.pSubq->pSelect);
+        }
+        if( pSrc->a[i].fg.isUsing==0 ){
+          mask |= sqlite3WhereExprUsage(pMaskSet, pSrc->a[i].u3.pOn);
+        }
+        if( pSrc->a[i].fg.isTabFunc ){
+          mask |= sqlite3WhereExprListUsage(pMaskSet, pSrc->a[i].u1.pFuncArg);
+        }
+      }
+    }
+    pS = pS->pPrior;
+  }
+  return mask;
+}
+
+/*
+** Expression pExpr is one operand of a comparison operator that might
+** be useful for indexing.  This routine checks to see if pExpr appears
+** in any index.  Return TRUE (1) if pExpr is an indexed term and return
+** FALSE (0) if not.  If TRUE is returned, also set aiCurCol[0] to the cursor
+** number of the table that is indexed and aiCurCol[1] to the column number
+** of the column that is indexed, or XN_EXPR (-2) if an expression is being
+** indexed.
+**
+** If pExpr is a TK_COLUMN column reference, then this routine always returns
+** true even if that particular column is not indexed, because the column
+** might be added to an automatic index later.
+*/
+static SQLITE_NOINLINE int exprMightBeIndexed2(
+  SrcList *pFrom,        /* The FROM clause */
+  int *aiCurCol,         /* Write the referenced table cursor and column here */
+  Expr *pExpr,           /* An operand of a comparison operator */
+  int j                  /* Start looking with the j-th pFrom entry */
+){
+  Index *pIdx;
+  int i;
+  int iCur;
+  do{
+    iCur = pFrom->a[j].iCursor;
+    for(pIdx=pFrom->a[j].pSTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      if( pIdx->aColExpr==0 ) continue;
+      for(i=0; i<pIdx->nKeyCol; i++){
+        if( pIdx->aiColumn[i]!=XN_EXPR ) continue;
+        assert( pIdx->bHasExpr );
+        if( sqlite3ExprCompareSkip(pExpr,pIdx->aColExpr->a[i].pExpr,iCur)==0
+         && !sqlite3ExprIsConstant(0,pIdx->aColExpr->a[i].pExpr)
+        ){
+          aiCurCol[0] = iCur;
+          aiCurCol[1] = XN_EXPR;
+          return 1;
+        }
+      }
+    }
+  }while( ++j < pFrom->nSrc );
+  return 0;
+}
+static int exprMightBeIndexed(
+  SrcList *pFrom,        /* The FROM clause */
+  int *aiCurCol,         /* Write the referenced table cursor & column here */
+  Expr *pExpr,           /* An operand of a comparison operator */
+  int op                 /* The specific comparison operator */
+){
+  int i;
+
+  /* If this expression is a vector to the left or right of a
+  ** inequality constraint (>, <, >= or <=), perform the processing
+  ** on the first element of the vector.  */
+  assert( TK_GT+1==TK_LE && TK_GT+2==TK_LT && TK_GT+3==TK_GE );
+  assert( TK_IS<TK_GE && TK_ISNULL<TK_GE && TK_IN<TK_GE );
+  assert( op<=TK_GE );
+  if( pExpr->op==TK_VECTOR && (op>=TK_GT && ALWAYS(op<=TK_GE)) ){
+    assert( ExprUseXList(pExpr) );
+    pExpr = pExpr->x.pList->a[0].pExpr;
+  }
+
+  if( pExpr->op==TK_COLUMN ){
+    aiCurCol[0] = pExpr->iTable;
+    aiCurCol[1] = pExpr->iColumn;
+    return 1;
+  }
+
+  for(i=0; i<pFrom->nSrc; i++){
+    Index *pIdx;
+    for(pIdx=pFrom->a[i].pSTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      if( pIdx->aColExpr ){
+        return exprMightBeIndexed2(pFrom,aiCurCol,pExpr,i);
+      }
+    }
+  }
+  return 0;
+}
+
+
+/*
+** The input to this routine is an WhereTerm structure with only the
+** "pExpr" field filled in.  The job of this routine is to analyze the
+** subexpression and populate all the other fields of the WhereTerm
+** structure.
+**
+** If the expression is of the form "<expr> <op> X" it gets commuted
+** to the standard form of "X <op> <expr>".
+**
+** If the expression is of the form "X <op> Y" where both X and Y are
+** columns, then the original expression is unchanged and a new virtual
+** term of the form "Y <op> X" is added to the WHERE clause and
+** analyzed separately.  The original term is marked with TERM_COPIED
+** and the new term is marked with TERM_DYNAMIC (because it's pExpr
+** needs to be freed with the WhereClause) and TERM_VIRTUAL (because it
+** is a commuted copy of a prior term.)  The original term has nChild=1
+** and the copy has idxParent set to the index of the original term.
+*/
+static void exprAnalyze(
+  SrcList *pSrc,            /* the FROM clause */
+  WhereClause *pWC,         /* the WHERE clause */
+  int idxTerm               /* Index of the term to be analyzed */
+){
+  WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */
+  WhereTerm *pTerm;                /* The term to be analyzed */
+  WhereMaskSet *pMaskSet;          /* Set of table index masks */
+  Expr *pExpr;                     /* The expression to be analyzed */
+  Bitmask prereqLeft;              /* Prerequisites of the pExpr->pLeft */
+  Bitmask prereqAll;               /* Prerequisites of pExpr */
+  Bitmask extraRight = 0;          /* Extra dependencies on LEFT JOIN */
+  Expr *pStr1 = 0;                 /* RHS of LIKE/GLOB operator */
+  int isComplete = 0;              /* RHS of LIKE/GLOB ends with wildcard */
+  int noCase = 0;                  /* uppercase equivalent to lowercase */
+  int op;                          /* Top-level operator.  pExpr->op */
+  Parse *pParse = pWInfo->pParse;  /* Parsing context */
+  sqlite3 *db = pParse->db;        /* Database connection */
+  unsigned char eOp2 = 0;          /* op2 value for LIKE/REGEXP/GLOB */
+  int nLeft;                       /* Number of elements on left side vector */
+
+  if( db->mallocFailed ){
+    return;
+  }
+  assert( pWC->nTerm > idxTerm );
+  pTerm = &pWC->a[idxTerm];
+  pMaskSet = &pWInfo->sMaskSet;
+  pExpr = pTerm->pExpr;
+  assert( pExpr!=0 ); /* Because malloc() has not failed */
+  assert( pExpr->op!=TK_AS && pExpr->op!=TK_COLLATE );
+  pMaskSet->bVarSelect = 0;
+  prereqLeft = sqlite3WhereExprUsage(pMaskSet, pExpr->pLeft);
+  op = pExpr->op;
+  if( op==TK_IN ){
+    assert( pExpr->pRight==0 );
+    if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
+    if( ExprUseXSelect(pExpr) ){
+      pTerm->prereqRight = exprSelectUsage(pMaskSet, pExpr->x.pSelect);
+    }else{
+      pTerm->prereqRight = sqlite3WhereExprListUsage(pMaskSet, pExpr->x.pList);
+    }
+    prereqAll = prereqLeft | pTerm->prereqRight;
+  }else{
+    pTerm->prereqRight = sqlite3WhereExprUsage(pMaskSet, pExpr->pRight);
+    if( pExpr->pLeft==0
+     || ExprHasProperty(pExpr, EP_xIsSelect|EP_IfNullRow)
+     || pExpr->x.pList!=0
+    ){
+      prereqAll = sqlite3WhereExprUsageNN(pMaskSet, pExpr);
+    }else{
+      prereqAll = prereqLeft | pTerm->prereqRight;
+    }
+  }
+  if( pMaskSet->bVarSelect ) pTerm->wtFlags |= TERM_VARSELECT;
+
+#ifdef SQLITE_DEBUG
+  if( prereqAll!=sqlite3WhereExprUsageNN(pMaskSet, pExpr) ){
+    printf("\n*** Incorrect prereqAll computed for:\n");
+    sqlite3TreeViewExpr(0,pExpr,0);
+    assert( 0 );
+  }
+#endif
+
+  if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON) ){
+    Bitmask x = sqlite3WhereGetMask(pMaskSet, pExpr->w.iJoin);
+    if( ExprHasProperty(pExpr, EP_OuterON) ){
+      prereqAll |= x;
+      extraRight = x-1;  /* ON clause terms may not be used with an index
+                         ** on left table of a LEFT JOIN.  Ticket #3015 */
+      if( (prereqAll>>1)>=x ){
+        sqlite3ErrorMsg(pParse, "ON clause references tables to its right");
+        return;
+      }
+    }else if( (prereqAll>>1)>=x ){
+      /* The ON clause of an INNER JOIN references a table to its right.
+      ** Most other SQL database engines raise an error.  But SQLite versions
+      ** 3.0 through 3.38 just put the ON clause constraint into the WHERE
+      ** clause and carried on.   Beginning with 3.39, raise an error only
+      ** if there is a RIGHT or FULL JOIN in the query.  This makes SQLite
+      ** more like other systems, and also preserves legacy. */
+      if( ALWAYS(pSrc->nSrc>0) && (pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){
+        sqlite3ErrorMsg(pParse, "ON clause references tables to its right");
+        return;
+      }
+      ExprClearProperty(pExpr, EP_InnerON);
+    }
+  }
+  pTerm->prereqAll = prereqAll;
+  pTerm->leftCursor = -1;
+  pTerm->iParent = -1;
+  pTerm->eOperator = 0;
+  if( allowedOp(op) ){
+    int aiCurCol[2];
+    Expr *pLeft = sqlite3ExprSkipCollate(pExpr->pLeft);
+    Expr *pRight = sqlite3ExprSkipCollate(pExpr->pRight);
+    u16 opMask = (pTerm->prereqRight & prereqLeft)==0 ? WO_ALL : WO_EQUIV;
+
+    if( pTerm->u.x.iField>0 ){
+      assert( op==TK_IN );
+      assert( pLeft->op==TK_VECTOR );
+      assert( ExprUseXList(pLeft) );
+      pLeft = pLeft->x.pList->a[pTerm->u.x.iField-1].pExpr;
+    }
+
+    if( exprMightBeIndexed(pSrc, aiCurCol, pLeft, op) ){
+      pTerm->leftCursor = aiCurCol[0];
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      pTerm->u.x.leftColumn = aiCurCol[1];
+      pTerm->eOperator = operatorMask(op) & opMask;
+    }
+    if( op==TK_IS ) pTerm->wtFlags |= TERM_IS;
+    if( pRight
+     && exprMightBeIndexed(pSrc, aiCurCol, pRight, op)
+     && !ExprHasProperty(pRight, EP_FixedCol)
+    ){
+      WhereTerm *pNew;
+      Expr *pDup;
+      u16 eExtraOp = 0;        /* Extra bits for pNew->eOperator */
+      assert( pTerm->u.x.iField==0 );
+      if( pTerm->leftCursor>=0 ){
+        int idxNew;
+        pDup = sqlite3ExprDup(db, pExpr, 0);
+        if( db->mallocFailed ){
+          sqlite3ExprDelete(db, pDup);
+          return;
+        }
+        idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
+        if( idxNew==0 ) return;
+        pNew = &pWC->a[idxNew];
+        markTermAsChild(pWC, idxNew, idxTerm);
+        if( op==TK_IS ) pNew->wtFlags |= TERM_IS;
+        pTerm = &pWC->a[idxTerm];
+        pTerm->wtFlags |= TERM_COPIED;
+
+        if( termIsEquivalence(pParse, pDup) ){
+          pTerm->eOperator |= WO_EQUIV;
+          eExtraOp = WO_EQUIV;
+        }
+      }else{
+        pDup = pExpr;
+        pNew = pTerm;
+      }
+      pNew->wtFlags |= exprCommute(pParse, pDup);
+      pNew->leftCursor = aiCurCol[0];
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      pNew->u.x.leftColumn = aiCurCol[1];
+      testcase( (prereqLeft | extraRight) != prereqLeft );
+      pNew->prereqRight = prereqLeft | extraRight;
+      pNew->prereqAll = prereqAll;
+      pNew->eOperator = (operatorMask(pDup->op) + eExtraOp) & opMask;
+    }else
+    if( op==TK_ISNULL
+     && !ExprHasProperty(pExpr,EP_OuterON)
+     && 0==sqlite3ExprCanBeNull(pLeft)
+    ){
+      assert( !ExprHasProperty(pExpr, EP_IntValue) );
+      pExpr->op = TK_TRUEFALSE;  /* See tag-20230504-1 */
+      pExpr->u.zToken = "false";
+      ExprSetProperty(pExpr, EP_IsFalse);
+      pTerm->prereqAll = 0;
+      pTerm->eOperator = 0;
+    }
+  }
+
+#ifndef SQLITE_OMIT_BETWEEN_OPTIMIZATION
+  /* If a term is the BETWEEN operator, create two new virtual terms
+  ** that define the range that the BETWEEN implements.  For example:
+  **
+  **      a BETWEEN b AND c
+  **
+  ** is converted into:
+  **
+  **      (a BETWEEN b AND c) AND (a>=b) AND (a<=c)
+  **
+  ** The two new terms are added onto the end of the WhereClause object.
+  ** The new terms are "dynamic" and are children of the original BETWEEN
+  ** term.  That means that if the BETWEEN term is coded, the children are
+  ** skipped.  Or, if the children are satisfied by an index, the original
+  ** BETWEEN term is skipped.
+  */
+  else if( pExpr->op==TK_BETWEEN && pWC->op==TK_AND ){
+    ExprList *pList;
+    int i;
+    static const u8 ops[] = {TK_GE, TK_LE};
+    assert( ExprUseXList(pExpr) );
+    pList = pExpr->x.pList;
+    assert( pList!=0 );
+    assert( pList->nExpr==2 );
+    for(i=0; i<2; i++){
+      Expr *pNewExpr;
+      int idxNew;
+      pNewExpr = sqlite3PExpr(pParse, ops[i],
+                             sqlite3ExprDup(db, pExpr->pLeft, 0),
+                             sqlite3ExprDup(db, pList->a[i].pExpr, 0));
+      transferJoinMarkings(pNewExpr, pExpr);
+      idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
+      testcase( idxNew==0 );
+      exprAnalyze(pSrc, pWC, idxNew);
+      pTerm = &pWC->a[idxTerm];
+      markTermAsChild(pWC, idxNew, idxTerm);
+    }
+  }
+#endif /* SQLITE_OMIT_BETWEEN_OPTIMIZATION */
+
+#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
+  /* Analyze a term that is composed of two or more subterms connected by
+  ** an OR operator.
+  */
+  else if( pExpr->op==TK_OR ){
+    assert( pWC->op==TK_AND );
+    exprAnalyzeOrTerm(pSrc, pWC, idxTerm);
+    pTerm = &pWC->a[idxTerm];
+  }
+#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
+  /* The form "x IS NOT NULL" can sometimes be evaluated more efficiently
+  ** as "x>NULL" if x is not an INTEGER PRIMARY KEY.  So construct a
+  ** virtual term of that form.
+  **
+  ** The virtual term must be tagged with TERM_VNULL.
+  */
+  else if( pExpr->op==TK_NOTNULL ){
+    if( pExpr->pLeft->op==TK_COLUMN
+     && pExpr->pLeft->iColumn>=0
+     && !ExprHasProperty(pExpr, EP_OuterON)
+    ){
+      Expr *pNewExpr;
+      Expr *pLeft = pExpr->pLeft;
+      int idxNew;
+      WhereTerm *pNewTerm;
+
+      pNewExpr = sqlite3PExpr(pParse, TK_GT,
+                              sqlite3ExprDup(db, pLeft, 0),
+                              sqlite3ExprAlloc(db, TK_NULL, 0, 0));
+
+      idxNew = whereClauseInsert(pWC, pNewExpr,
+                                TERM_VIRTUAL|TERM_DYNAMIC|TERM_VNULL);
+      if( idxNew ){
+        pNewTerm = &pWC->a[idxNew];
+        pNewTerm->prereqRight = 0;
+        pNewTerm->leftCursor = pLeft->iTable;
+        pNewTerm->u.x.leftColumn = pLeft->iColumn;
+        pNewTerm->eOperator = WO_GT;
+        markTermAsChild(pWC, idxNew, idxTerm);
+        pTerm = &pWC->a[idxTerm];
+        pTerm->wtFlags |= TERM_COPIED;
+        pNewTerm->prereqAll = pTerm->prereqAll;
+      }
+    }
+  }
+
+
+#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
+  /* Add constraints to reduce the search space on a LIKE or GLOB
+  ** operator.
+  **
+  ** A like pattern of the form "x LIKE 'aBc%'" is changed into constraints
+  **
+  **          x>='ABC' AND x<'abd' AND x LIKE 'aBc%'
+  **
+  ** The last character of the prefix "abc" is incremented to form the
+  ** termination condition "abd".  If case is not significant (the default
+  ** for LIKE) then the lower-bound is made all uppercase and the upper-
+  ** bound is made all lowercase so that the bounds also work when comparing
+  ** BLOBs.
+  */
+  else if( pExpr->op==TK_FUNCTION
+   && pWC->op==TK_AND
+   && isLikeOrGlob(pParse, pExpr, &pStr1, &isComplete, &noCase)
+  ){
+    Expr *pLeft;       /* LHS of LIKE/GLOB operator */
+    Expr *pStr2;       /* Copy of pStr1 - RHS of LIKE/GLOB operator */
+    Expr *pNewExpr1;
+    Expr *pNewExpr2;
+    int idxNew1;
+    int idxNew2;
+    const char *zCollSeqName;     /* Name of collating sequence */
+    const u16 wtFlags = TERM_LIKEOPT | TERM_VIRTUAL | TERM_DYNAMIC;
+
+    assert( ExprUseXList(pExpr) );
+    pLeft = pExpr->x.pList->a[1].pExpr;
+    pStr2 = sqlite3ExprDup(db, pStr1, 0);
+    assert( pStr1==0 || !ExprHasProperty(pStr1, EP_IntValue) );
+    assert( pStr2==0 || !ExprHasProperty(pStr2, EP_IntValue) );
+
+
+    /* Convert the lower bound to upper-case and the upper bound to
+    ** lower-case (upper-case is less than lower-case in ASCII) so that
+    ** the range constraints also work for BLOBs
+    */
+    if( noCase && !pParse->db->mallocFailed ){
+      int i;
+      char c;
+      pTerm->wtFlags |= TERM_LIKE;
+      for(i=0; (c = pStr1->u.zToken[i])!=0; i++){
+        pStr1->u.zToken[i] = sqlite3Toupper(c);
+        pStr2->u.zToken[i] = sqlite3Tolower(c);
+      }
+    }
+
+    if( !db->mallocFailed ){
+      u8 *pC;       /* Last character before the first wildcard */
+      pC = (u8*)&pStr2->u.zToken[sqlite3Strlen30(pStr2->u.zToken)-1];
+      if( noCase ){
+        /* The point is to increment the last character before the first
+        ** wildcard.  But if we increment '@', that will push it into the
+        ** alphabetic range where case conversions will mess up the
+        ** inequality.  To avoid this, make sure to also run the full
+        ** LIKE on all candidate expressions by clearing the isComplete flag
+        */
+        if( *pC=='A'-1 ) isComplete = 0;
+        *pC = sqlite3UpperToLower[*pC];
+      }
+
+      /* Increment the value of the last utf8 character in the prefix. */
+      while( *pC==0xBF && pC>(u8*)pStr2->u.zToken ){
+        *pC = 0x80;
+        pC--;
+      }
+      assert( *pC!=0xFF );        /* isLikeOrGlob() guarantees this */
+      (*pC)++;
+    }
+    zCollSeqName = noCase ? "NOCASE" : sqlite3StrBINARY;
+    pNewExpr1 = sqlite3ExprDup(db, pLeft, 0);
+    pNewExpr1 = sqlite3PExpr(pParse, TK_GE,
+           sqlite3ExprAddCollateString(pParse,pNewExpr1,zCollSeqName),
+           pStr1);
+    transferJoinMarkings(pNewExpr1, pExpr);
+    idxNew1 = whereClauseInsert(pWC, pNewExpr1, wtFlags);
+    testcase( idxNew1==0 );
+    pNewExpr2 = sqlite3ExprDup(db, pLeft, 0);
+    pNewExpr2 = sqlite3PExpr(pParse, TK_LT,
+           sqlite3ExprAddCollateString(pParse,pNewExpr2,zCollSeqName),
+           pStr2);
+    transferJoinMarkings(pNewExpr2, pExpr);
+    idxNew2 = whereClauseInsert(pWC, pNewExpr2, wtFlags);
+    testcase( idxNew2==0 );
+    exprAnalyze(pSrc, pWC, idxNew1);
+    exprAnalyze(pSrc, pWC, idxNew2);
+    pTerm = &pWC->a[idxTerm];
+    if( isComplete ){
+      markTermAsChild(pWC, idxNew1, idxTerm);
+      markTermAsChild(pWC, idxNew2, idxTerm);
+    }
+  }
+#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
+
+  /* If there is a vector == or IS term - e.g. "(a, b) == (?, ?)" - create
+  ** new terms for each component comparison - "a = ?" and "b = ?".  The
+  ** new terms completely replace the original vector comparison, which is
+  ** no longer used.
+  **
+  ** This is only required if at least one side of the comparison operation
+  ** is not a sub-select.
+  **
+  ** tag-20220128a
+  */
+  if( (pExpr->op==TK_EQ || pExpr->op==TK_IS)
+   && (nLeft = sqlite3ExprVectorSize(pExpr->pLeft))>1
+   && sqlite3ExprVectorSize(pExpr->pRight)==nLeft
+   && ( (pExpr->pLeft->flags & EP_xIsSelect)==0
+     || (pExpr->pRight->flags & EP_xIsSelect)==0)
+   && pWC->op==TK_AND
+  ){
+    int i;
+    for(i=0; i<nLeft; i++){
+      int idxNew;
+      Expr *pNew;
+      Expr *pLeft = sqlite3ExprForVectorField(pParse, pExpr->pLeft, i, nLeft);
+      Expr *pRight = sqlite3ExprForVectorField(pParse, pExpr->pRight, i, nLeft);
+
+      pNew = sqlite3PExpr(pParse, pExpr->op, pLeft, pRight);
+      transferJoinMarkings(pNew, pExpr);
+      idxNew = whereClauseInsert(pWC, pNew, TERM_DYNAMIC|TERM_SLICE);
+      exprAnalyze(pSrc, pWC, idxNew);
+    }
+    pTerm = &pWC->a[idxTerm];
+    pTerm->wtFlags |= TERM_CODED|TERM_VIRTUAL;  /* Disable the original */
+    pTerm->eOperator = WO_ROWVAL;
+  }
+
+  /* If there is a vector IN term - e.g. "(a, b) IN (SELECT ...)" - create
+  ** a virtual term for each vector component. The expression object
+  ** used by each such virtual term is pExpr (the full vector IN(...)
+  ** expression). The WhereTerm.u.x.iField variable identifies the index within
+  ** the vector on the LHS that the virtual term represents.
+  **
+  ** This only works if the RHS is a simple SELECT (not a compound) that does
+  ** not use window functions.
+  */
+  else if( pExpr->op==TK_IN
+   && pTerm->u.x.iField==0
+   && pExpr->pLeft->op==TK_VECTOR
+   && ALWAYS( ExprUseXSelect(pExpr) )
+   && (pExpr->x.pSelect->pPrior==0 || (pExpr->x.pSelect->selFlags & SF_Values))
+#ifndef SQLITE_OMIT_WINDOWFUNC
+   && pExpr->x.pSelect->pWin==0
+#endif
+   && pWC->op==TK_AND
+  ){
+    int i;
+    for(i=0; i<sqlite3ExprVectorSize(pExpr->pLeft); i++){
+      int idxNew;
+      idxNew = whereClauseInsert(pWC, pExpr, TERM_VIRTUAL|TERM_SLICE);
+      pWC->a[idxNew].u.x.iField = i+1;
+      exprAnalyze(pSrc, pWC, idxNew);
+      markTermAsChild(pWC, idxNew, idxTerm);
+    }
+  }
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  /* Add a WO_AUX auxiliary term to the constraint set if the
+  ** current expression is of the form "column OP expr" where OP
+  ** is an operator that gets passed into virtual tables but which is
+  ** not normally optimized for ordinary tables.  In other words, OP
+  ** is one of MATCH, LIKE, GLOB, REGEXP, !=, IS, IS NOT, or NOT NULL.
+  ** This information is used by the xBestIndex methods of
+  ** virtual tables.  The native query optimizer does not attempt
+  ** to do anything with MATCH functions.
+  */
+  else if( pWC->op==TK_AND ){
+    Expr *pRight = 0, *pLeft = 0;
+    int res = isAuxiliaryVtabOperator(db, pExpr, &eOp2, &pLeft, &pRight);
+    while( res-- > 0 ){
+      int idxNew;
+      WhereTerm *pNewTerm;
+      Bitmask prereqColumn, prereqExpr;
+
+      prereqExpr = sqlite3WhereExprUsage(pMaskSet, pRight);
+      prereqColumn = sqlite3WhereExprUsage(pMaskSet, pLeft);
+      if( (prereqExpr & prereqColumn)==0 ){
+        Expr *pNewExpr;
+        pNewExpr = sqlite3PExpr(pParse, TK_MATCH,
+            0, sqlite3ExprDup(db, pRight, 0));
+        if( ExprHasProperty(pExpr, EP_OuterON) && pNewExpr ){
+          ExprSetProperty(pNewExpr, EP_OuterON);
+          pNewExpr->w.iJoin = pExpr->w.iJoin;
+        }
+        idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
+        testcase( idxNew==0 );
+        pNewTerm = &pWC->a[idxNew];
+        pNewTerm->prereqRight = prereqExpr;
+        pNewTerm->leftCursor = pLeft->iTable;
+        pNewTerm->u.x.leftColumn = pLeft->iColumn;
+        pNewTerm->eOperator = WO_AUX;
+        pNewTerm->eMatchOp = eOp2;
+        markTermAsChild(pWC, idxNew, idxTerm);
+        pTerm = &pWC->a[idxTerm];
+        pTerm->wtFlags |= TERM_COPIED;
+        pNewTerm->prereqAll = pTerm->prereqAll;
+      }
+      SWAP(Expr*, pLeft, pRight);
+    }
+  }
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+  /* Prevent ON clause terms of a LEFT JOIN from being used to drive
+  ** an index for tables to the left of the join.
+  */
+  testcase( pTerm!=&pWC->a[idxTerm] );
+  pTerm = &pWC->a[idxTerm];
+  pTerm->prereqRight |= extraRight;
+}
+
+/***************************************************************************
+** Routines with file scope above.  Interface to the rest of the where.c
+** subsystem follows.
+***************************************************************************/
+
+/*
+** This routine identifies subexpressions in the WHERE clause where
+** each subexpression is separated by the AND operator or some other
+** operator specified in the op parameter.  The WhereClause structure
+** is filled with pointers to subexpressions.  For example:
+**
+**    WHERE  a=='hello' AND coalesce(b,11)<10 AND (c+12!=d OR c==22)
+**           \________/     \_______________/     \________________/
+**            slot[0]            slot[1]               slot[2]
+**
+** The original WHERE clause in pExpr is unaltered.  All this routine
+** does is make slot[] entries point to substructure within pExpr.
+**
+** In the previous sentence and in the diagram, "slot[]" refers to
+** the WhereClause.a[] array.  The slot[] array grows as needed to contain
+** all terms of the WHERE clause.
+*/
+SQLITE_PRIVATE void sqlite3WhereSplit(WhereClause *pWC, Expr *pExpr, u8 op){
+  Expr *pE2 = sqlite3ExprSkipCollateAndLikely(pExpr);
+  pWC->op = op;
+  assert( pE2!=0 || pExpr==0 );
+  if( pE2==0 ) return;
+  if( pE2->op!=op ){
+    whereClauseInsert(pWC, pExpr, 0);
+  }else{
+    sqlite3WhereSplit(pWC, pE2->pLeft, op);
+    sqlite3WhereSplit(pWC, pE2->pRight, op);
+  }
+}
+
+/*
+** Add either a LIMIT (if eMatchOp==SQLITE_INDEX_CONSTRAINT_LIMIT) or
+** OFFSET (if eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET) term to the
+** where-clause passed as the first argument. The value for the term
+** is found in register iReg.
+**
+** In the common case where the value is a simple integer
+** (example: "LIMIT 5 OFFSET 10") then the expression codes as a
+** TK_INTEGER so that it will be available to sqlite3_vtab_rhs_value().
+** If not, then it codes as a TK_REGISTER expression.
+*/
+static void whereAddLimitExpr(
+  WhereClause *pWC,   /* Add the constraint to this WHERE clause */
+  int iReg,           /* Register that will hold value of the limit/offset */
+  Expr *pExpr,        /* Expression that defines the limit/offset */
+  int iCsr,           /* Cursor to which the constraint applies */
+  int eMatchOp        /* SQLITE_INDEX_CONSTRAINT_LIMIT or _OFFSET */
+){
+  Parse *pParse = pWC->pWInfo->pParse;
+  sqlite3 *db = pParse->db;
+  Expr *pNew;
+  int iVal = 0;
+
+  if( sqlite3ExprIsInteger(pExpr, &iVal, pParse) && iVal>=0 ){
+    Expr *pVal = sqlite3Expr(db, TK_INTEGER, 0);
+    if( pVal==0 ) return;
+    ExprSetProperty(pVal, EP_IntValue);
+    pVal->u.iValue = iVal;
+    pNew = sqlite3PExpr(pParse, TK_MATCH, 0, pVal);
+  }else{
+    Expr *pVal = sqlite3Expr(db, TK_REGISTER, 0);
+    if( pVal==0 ) return;
+    pVal->iTable = iReg;
+    pNew = sqlite3PExpr(pParse, TK_MATCH, 0, pVal);
+  }
+  if( pNew ){
+    WhereTerm *pTerm;
+    int idx;
+    idx = whereClauseInsert(pWC, pNew, TERM_DYNAMIC|TERM_VIRTUAL);
+    pTerm = &pWC->a[idx];
+    pTerm->leftCursor = iCsr;
+    pTerm->eOperator = WO_AUX;
+    pTerm->eMatchOp = eMatchOp;
+  }
+}
+
+/*
+** Possibly add terms corresponding to the LIMIT and OFFSET clauses of the
+** SELECT statement passed as the second argument. These terms are only
+** added if:
+**
+**   1. The SELECT statement has a LIMIT clause, and
+**   2. The SELECT statement is not an aggregate or DISTINCT query, and
+**   3. The SELECT statement has exactly one object in its from clause, and
+**      that object is a virtual table, and
+**   4. There are no terms in the WHERE clause that will not be passed
+**      to the virtual table xBestIndex method.
+**   5. The ORDER BY clause, if any, will be made available to the xBestIndex
+**      method.
+**
+** LIMIT and OFFSET terms are ignored by most of the planner code. They
+** exist only so that they may be passed to the xBestIndex method of the
+** single virtual table in the FROM clause of the SELECT.
+*/
+SQLITE_PRIVATE void SQLITE_NOINLINE sqlite3WhereAddLimit(WhereClause *pWC, Select *p){
+  assert( p!=0 && p->pLimit!=0 );                 /* 1 -- checked by caller */
+  if( p->pGroupBy==0
+   && (p->selFlags & (SF_Distinct|SF_Aggregate))==0             /* 2 */
+   && (p->pSrc->nSrc==1 && IsVirtual(p->pSrc->a[0].pSTab))      /* 3 */
+  ){
+    ExprList *pOrderBy = p->pOrderBy;
+    int iCsr = p->pSrc->a[0].iCursor;
+    int ii;
+
+    /* Check condition (4). Return early if it is not met. */
+    for(ii=0; ii<pWC->nTerm; ii++){
+      if( pWC->a[ii].wtFlags & TERM_CODED ){
+        /* This term is a vector operation that has been decomposed into
+        ** other, subsequent terms.  It can be ignored. See tag-20220128a */
+        assert( pWC->a[ii].wtFlags & TERM_VIRTUAL );
+        assert( pWC->a[ii].eOperator==WO_ROWVAL );
+        continue;
+      }
+      if( pWC->a[ii].nChild ){
+        /* If this term has child terms, then they are also part of the
+        ** pWC->a[] array. So this term can be ignored, as a LIMIT clause
+        ** will only be added if each of the child terms passes the
+        ** (leftCursor==iCsr) test below.  */
+        continue;
+      }
+      if( pWC->a[ii].leftCursor!=iCsr ) return;
+      if( pWC->a[ii].prereqRight!=0 ) return;
+    }
+
+    /* Check condition (5). Return early if it is not met. */
+    if( pOrderBy ){
+      for(ii=0; ii<pOrderBy->nExpr; ii++){
+        Expr *pExpr = pOrderBy->a[ii].pExpr;
+        if( pExpr->op!=TK_COLUMN ) return;
+        if( pExpr->iTable!=iCsr ) return;
+        if( pOrderBy->a[ii].fg.sortFlags & KEYINFO_ORDER_BIGNULL ) return;
+      }
+    }
+
+    /* All conditions are met. Add the terms to the where-clause object. */
+    assert( p->pLimit->op==TK_LIMIT );
+    if( p->iOffset!=0 && (p->selFlags & SF_Compound)==0 ){
+      whereAddLimitExpr(pWC, p->iOffset, p->pLimit->pRight,
+                        iCsr, SQLITE_INDEX_CONSTRAINT_OFFSET);
+    }
+    if( p->iOffset==0 || (p->selFlags & SF_Compound)==0 ){
+      whereAddLimitExpr(pWC, p->iLimit, p->pLimit->pLeft,
+                        iCsr, SQLITE_INDEX_CONSTRAINT_LIMIT);
+    }
+  }
+}
+
+/*
+** Initialize a preallocated WhereClause structure.
+*/
+SQLITE_PRIVATE void sqlite3WhereClauseInit(
+  WhereClause *pWC,        /* The WhereClause to be initialized */
+  WhereInfo *pWInfo        /* The WHERE processing context */
+){
+  pWC->pWInfo = pWInfo;
+  pWC->hasOr = 0;
+  pWC->pOuter = 0;
+  pWC->nTerm = 0;
+  pWC->nBase = 0;
+  pWC->nSlot = ArraySize(pWC->aStatic);
+  pWC->a = pWC->aStatic;
+}
+
+/*
+** Deallocate a WhereClause structure.  The WhereClause structure
+** itself is not freed.  This routine is the inverse of
+** sqlite3WhereClauseInit().
+*/
+SQLITE_PRIVATE void sqlite3WhereClauseClear(WhereClause *pWC){
+  sqlite3 *db = pWC->pWInfo->pParse->db;
+  assert( pWC->nTerm>=pWC->nBase );
+  if( pWC->nTerm>0 ){
+    WhereTerm *a = pWC->a;
+    WhereTerm *aLast = &pWC->a[pWC->nTerm-1];
+#ifdef SQLITE_DEBUG
+    int i;
+    /* Verify that every term past pWC->nBase is virtual */
+    for(i=pWC->nBase; i<pWC->nTerm; i++){
+      assert( (pWC->a[i].wtFlags & TERM_VIRTUAL)!=0 );
+    }
+#endif
+    while(1){
+      assert( a->eMatchOp==0 || a->eOperator==WO_AUX );
+      if( a->wtFlags & TERM_DYNAMIC ){
+        sqlite3ExprDelete(db, a->pExpr);
+      }
+      if( a->wtFlags & (TERM_ORINFO|TERM_ANDINFO) ){
+        if( a->wtFlags & TERM_ORINFO ){
+          assert( (a->wtFlags & TERM_ANDINFO)==0 );
+          whereOrInfoDelete(db, a->u.pOrInfo);
+        }else{
+          assert( (a->wtFlags & TERM_ANDINFO)!=0 );
+          whereAndInfoDelete(db, a->u.pAndInfo);
+        }
+      }
+      if( a==aLast ) break;
+      a++;
+    }
+  }
+}
+
+
+/*
+** These routines walk (recursively) an expression tree and generate
+** a bitmask indicating which tables are used in that expression
+** tree.
+**
+** sqlite3WhereExprUsage(MaskSet, Expr) ->
+**
+**       Return a Bitmask of all tables referenced by Expr.  Expr can be
+**       be NULL, in which case 0 is returned.
+**
+** sqlite3WhereExprUsageNN(MaskSet, Expr) ->
+**
+**       Same as sqlite3WhereExprUsage() except that Expr must not be
+**       NULL.  The "NN" suffix on the name stands for "Not Null".
+**
+** sqlite3WhereExprListUsage(MaskSet, ExprList) ->
+**
+**       Return a Bitmask of all tables referenced by every expression
+**       in the expression list ExprList.  ExprList can be NULL, in which
+**       case 0 is returned.
+**
+** sqlite3WhereExprUsageFull(MaskSet, ExprList) ->
+**
+**       Internal use only.  Called only by sqlite3WhereExprUsageNN() for
+**       complex expressions that require pushing register values onto
+**       the stack.  Many calls to sqlite3WhereExprUsageNN() do not need
+**       the more complex analysis done by this routine.  Hence, the
+**       computations done by this routine are broken out into a separate
+**       "no-inline" function to avoid the stack push overhead in the
+**       common case where it is not needed.
+*/
+static SQLITE_NOINLINE Bitmask sqlite3WhereExprUsageFull(
+  WhereMaskSet *pMaskSet,
+  Expr *p
+){
+  Bitmask mask;
+  mask = (p->op==TK_IF_NULL_ROW) ? sqlite3WhereGetMask(pMaskSet, p->iTable) : 0;
+  if( p->pLeft ) mask |= sqlite3WhereExprUsageNN(pMaskSet, p->pLeft);
+  if( p->pRight ){
+    mask |= sqlite3WhereExprUsageNN(pMaskSet, p->pRight);
+    assert( p->x.pList==0 );
+  }else if( ExprUseXSelect(p) ){
+    if( ExprHasProperty(p, EP_VarSelect) ) pMaskSet->bVarSelect = 1;
+    mask |= exprSelectUsage(pMaskSet, p->x.pSelect);
+  }else if( p->x.pList ){
+    mask |= sqlite3WhereExprListUsage(pMaskSet, p->x.pList);
+  }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( (p->op==TK_FUNCTION || p->op==TK_AGG_FUNCTION) && ExprUseYWin(p) ){
+    assert( p->y.pWin!=0 );
+    mask |= sqlite3WhereExprListUsage(pMaskSet, p->y.pWin->pPartition);
+    mask |= sqlite3WhereExprListUsage(pMaskSet, p->y.pWin->pOrderBy);
+    mask |= sqlite3WhereExprUsage(pMaskSet, p->y.pWin->pFilter);
+  }
+#endif
+  return mask;
+}
+SQLITE_PRIVATE Bitmask sqlite3WhereExprUsageNN(WhereMaskSet *pMaskSet, Expr *p){
+  if( p->op==TK_COLUMN && !ExprHasProperty(p, EP_FixedCol) ){
+    return sqlite3WhereGetMask(pMaskSet, p->iTable);
+  }else if( ExprHasProperty(p, EP_TokenOnly|EP_Leaf) ){
+    assert( p->op!=TK_IF_NULL_ROW );
+    return 0;
+  }
+  return sqlite3WhereExprUsageFull(pMaskSet, p);
+}
+SQLITE_PRIVATE Bitmask sqlite3WhereExprUsage(WhereMaskSet *pMaskSet, Expr *p){
+  return p ? sqlite3WhereExprUsageNN(pMaskSet,p) : 0;
+}
+SQLITE_PRIVATE Bitmask sqlite3WhereExprListUsage(WhereMaskSet *pMaskSet, ExprList *pList){
+  int i;
+  Bitmask mask = 0;
+  if( pList ){
+    for(i=0; i<pList->nExpr; i++){
+      mask |= sqlite3WhereExprUsage(pMaskSet, pList->a[i].pExpr);
+    }
+  }
+  return mask;
+}
+
+
+/*
+** Call exprAnalyze on all terms in a WHERE clause.
+**
+** Note that exprAnalyze() might add new virtual terms onto the
+** end of the WHERE clause.  We do not want to analyze these new
+** virtual terms, so start analyzing at the end and work forward
+** so that the added virtual terms are never processed.
+*/
+SQLITE_PRIVATE void sqlite3WhereExprAnalyze(
+  SrcList *pTabList,       /* the FROM clause */
+  WhereClause *pWC         /* the WHERE clause to be analyzed */
+){
+  int i;
+  for(i=pWC->nTerm-1; i>=0; i--){
+    exprAnalyze(pTabList, pWC, i);
+  }
+}
+
+/*
+** For table-valued-functions, transform the function arguments into
+** new WHERE clause terms.
+**
+** Each function argument translates into an equality constraint against
+** a HIDDEN column in the table.
+*/
+SQLITE_PRIVATE void sqlite3WhereTabFuncArgs(
+  Parse *pParse,                    /* Parsing context */
+  SrcItem *pItem,                   /* The FROM clause term to process */
+  WhereClause *pWC                  /* Xfer function arguments to here */
+){
+  Table *pTab;
+  int j, k;
+  ExprList *pArgs;
+  Expr *pColRef;
+  Expr *pTerm;
+  if( pItem->fg.isTabFunc==0 ) return;
+  pTab = pItem->pSTab;
+  assert( pTab!=0 );
+  pArgs = pItem->u1.pFuncArg;
+  if( pArgs==0 ) return;
+  for(j=k=0; j<pArgs->nExpr; j++){
+    Expr *pRhs;
+    u32 joinType;
+    while( k<pTab->nCol && (pTab->aCol[k].colFlags & COLFLAG_HIDDEN)==0 ){k++;}
+    if( k>=pTab->nCol ){
+      sqlite3ErrorMsg(pParse, "too many arguments on %s() - max %d",
+                      pTab->zName, j);
+      return;
+    }
+    pColRef = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0);
+    if( pColRef==0 ) return;
+    pColRef->iTable = pItem->iCursor;
+    pColRef->iColumn = k++;
+    assert( ExprUseYTab(pColRef) );
+    pColRef->y.pTab = pTab;
+    pItem->colUsed |= sqlite3ExprColUsed(pColRef);
+    pRhs = sqlite3PExpr(pParse, TK_UPLUS,
+        sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0), 0);
+    pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef, pRhs);
+    if( pItem->fg.jointype & (JT_LEFT|JT_RIGHT) ){
+      testcase( pItem->fg.jointype & JT_LEFT );  /* testtag-20230227a */
+      testcase( pItem->fg.jointype & JT_RIGHT ); /* testtag-20230227b */
+      joinType = EP_OuterON;
+    }else{
+      testcase( pItem->fg.jointype & JT_LTORJ ); /* testtag-20230227c */
+      joinType = EP_InnerON;
+    }
+    sqlite3SetJoinExpr(pTerm, pItem->iCursor, joinType);
+    whereClauseInsert(pWC, pTerm, TERM_DYNAMIC);
+  }
+}
+
+/************** End of whereexpr.c *******************************************/
+/************** Begin file where.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This module contains C code that generates VDBE code used to process
+** the WHERE clause of SQL statements.  This module is responsible for
+** generating the code that loops through a table looking for applicable
+** rows.  Indices are selected and used to speed the search when doing
+** so is applicable.  Because this module is responsible for selecting
+** indices, you might also think of this module as the "query optimizer".
+*/
+/* #include "sqliteInt.h" */
+/* #include "whereInt.h" */
+
+/*
+** Extra information appended to the end of sqlite3_index_info but not
+** visible to the xBestIndex function, at least not directly.  The
+** sqlite3_vtab_collation() interface knows how to reach it, however.
+**
+** This object is not an API and can be changed from one release to the
+** next.  As long as allocateIndexInfo() and sqlite3_vtab_collation()
+** agree on the structure, all will be well.
+*/
+typedef struct HiddenIndexInfo HiddenIndexInfo;
+struct HiddenIndexInfo {
+  WhereClause *pWC;        /* The Where clause being analyzed */
+  Parse *pParse;           /* The parsing context */
+  int eDistinct;           /* Value to return from sqlite3_vtab_distinct() */
+  u32 mIn;                 /* Mask of terms that are <col> IN (...) */
+  u32 mHandleIn;           /* Terms that vtab will handle as <col> IN (...) */
+  sqlite3_value *aRhs[1];  /* RHS values for constraints. MUST BE LAST
+                           ** because extra space is allocated to hold up
+                           ** to nTerm such values */
+};
+
+/* Forward declaration of methods */
+static int whereLoopResize(sqlite3*, WhereLoop*, int);
+
+/*
+** Return the estimated number of output rows from a WHERE clause
+*/
+SQLITE_PRIVATE LogEst sqlite3WhereOutputRowCount(WhereInfo *pWInfo){
+  return pWInfo->nRowOut;
+}
+
+/*
+** Return one of the WHERE_DISTINCT_xxxxx values to indicate how this
+** WHERE clause returns outputs for DISTINCT processing.
+*/
+SQLITE_PRIVATE int sqlite3WhereIsDistinct(WhereInfo *pWInfo){
+  return pWInfo->eDistinct;
+}
+
+/*
+** Return the number of ORDER BY terms that are satisfied by the
+** WHERE clause.  A return of 0 means that the output must be
+** completely sorted.  A return equal to the number of ORDER BY
+** terms means that no sorting is needed at all.  A return that
+** is positive but less than the number of ORDER BY terms means that
+** block sorting is required.
+*/
+SQLITE_PRIVATE int sqlite3WhereIsOrdered(WhereInfo *pWInfo){
+  return pWInfo->nOBSat<0 ? 0 : pWInfo->nOBSat;
+}
+
+/*
+** In the ORDER BY LIMIT optimization, if the inner-most loop is known
+** to emit rows in increasing order, and if the last row emitted by the
+** inner-most loop did not fit within the sorter, then we can skip all
+** subsequent rows for the current iteration of the inner loop (because they
+** will not fit in the sorter either) and continue with the second inner
+** loop - the loop immediately outside the inner-most.
+**
+** When a row does not fit in the sorter (because the sorter already
+** holds LIMIT+OFFSET rows that are smaller), then a jump is made to the
+** label returned by this function.
+**
+** If the ORDER BY LIMIT optimization applies, the jump destination should
+** be the continuation for the second-inner-most loop.  If the ORDER BY
+** LIMIT optimization does not apply, then the jump destination should
+** be the continuation for the inner-most loop.
+**
+** It is always safe for this routine to return the continuation of the
+** inner-most loop, in the sense that a correct answer will result.
+** Returning the continuation the second inner loop is an optimization
+** that might make the code run a little faster, but should not change
+** the final answer.
+*/
+SQLITE_PRIVATE int sqlite3WhereOrderByLimitOptLabel(WhereInfo *pWInfo){
+  WhereLevel *pInner;
+  if( !pWInfo->bOrderedInnerLoop ){
+    /* The ORDER BY LIMIT optimization does not apply.  Jump to the
+    ** continuation of the inner-most loop. */
+    return pWInfo->iContinue;
+  }
+  pInner = &pWInfo->a[pWInfo->nLevel-1];
+  assert( pInner->addrNxt!=0 );
+  return pInner->pRJ ? pWInfo->iContinue : pInner->addrNxt;
+}
+
+/*
+** While generating code for the min/max optimization, after handling
+** the aggregate-step call to min() or max(), check to see if any
+** additional looping is required.  If the output order is such that
+** we are certain that the correct answer has already been found, then
+** code an OP_Goto to by pass subsequent processing.
+**
+** Any extra OP_Goto that is coded here is an optimization.  The
+** correct answer should be obtained regardless.  This OP_Goto just
+** makes the answer appear faster.
+*/
+SQLITE_PRIVATE void sqlite3WhereMinMaxOptEarlyOut(Vdbe *v, WhereInfo *pWInfo){
+  WhereLevel *pInner;
+  int i;
+  if( !pWInfo->bOrderedInnerLoop ) return;
+  if( pWInfo->nOBSat==0 ) return;
+  for(i=pWInfo->nLevel-1; i>=0; i--){
+    pInner = &pWInfo->a[i];
+    if( (pInner->pWLoop->wsFlags & WHERE_COLUMN_IN)!=0 ){
+      sqlite3VdbeGoto(v, pInner->addrNxt);
+      return;
+    }
+  }
+  sqlite3VdbeGoto(v, pWInfo->iBreak);
+}
+
+/*
+** Return the VDBE address or label to jump to in order to continue
+** immediately with the next row of a WHERE clause.
+*/
+SQLITE_PRIVATE int sqlite3WhereContinueLabel(WhereInfo *pWInfo){
+  assert( pWInfo->iContinue!=0 );
+  return pWInfo->iContinue;
+}
+
+/*
+** Return the VDBE address or label to jump to in order to break
+** out of a WHERE loop.
+*/
+SQLITE_PRIVATE int sqlite3WhereBreakLabel(WhereInfo *pWInfo){
+  return pWInfo->iBreak;
+}
+
+/*
+** Return ONEPASS_OFF (0) if an UPDATE or DELETE statement is unable to
+** operate directly on the rowids returned by a WHERE clause.  Return
+** ONEPASS_SINGLE (1) if the statement can operation directly because only
+** a single row is to be changed.  Return ONEPASS_MULTI (2) if the one-pass
+** optimization can be used on multiple
+**
+** If the ONEPASS optimization is used (if this routine returns true)
+** then also write the indices of open cursors used by ONEPASS
+** into aiCur[0] and aiCur[1].  iaCur[0] gets the cursor of the data
+** table and iaCur[1] gets the cursor used by an auxiliary index.
+** Either value may be -1, indicating that cursor is not used.
+** Any cursors returned will have been opened for writing.
+**
+** aiCur[0] and aiCur[1] both get -1 if the where-clause logic is
+** unable to use the ONEPASS optimization.
+*/
+SQLITE_PRIVATE int sqlite3WhereOkOnePass(WhereInfo *pWInfo, int *aiCur){
+  memcpy(aiCur, pWInfo->aiCurOnePass, sizeof(int)*2);
+#ifdef WHERETRACE_ENABLED
+  if( sqlite3WhereTrace && pWInfo->eOnePass!=ONEPASS_OFF ){
+    sqlite3DebugPrintf("%s cursors: %d %d\n",
+         pWInfo->eOnePass==ONEPASS_SINGLE ? "ONEPASS_SINGLE" : "ONEPASS_MULTI",
+         aiCur[0], aiCur[1]);
+  }
+#endif
+  return pWInfo->eOnePass;
+}
+
+/*
+** Return TRUE if the WHERE loop uses the OP_DeferredSeek opcode to move
+** the data cursor to the row selected by the index cursor.
+*/
+SQLITE_PRIVATE int sqlite3WhereUsesDeferredSeek(WhereInfo *pWInfo){
+  return pWInfo->bDeferredSeek;
+}
+
+/*
+** Move the content of pSrc into pDest
+*/
+static void whereOrMove(WhereOrSet *pDest, WhereOrSet *pSrc){
+  pDest->n = pSrc->n;
+  memcpy(pDest->a, pSrc->a, pDest->n*sizeof(pDest->a[0]));
+}
+
+/*
+** Try to insert a new prerequisite/cost entry into the WhereOrSet pSet.
+**
+** The new entry might overwrite an existing entry, or it might be
+** appended, or it might be discarded.  Do whatever is the right thing
+** so that pSet keeps the N_OR_COST best entries seen so far.
+*/
+static int whereOrInsert(
+  WhereOrSet *pSet,      /* The WhereOrSet to be updated */
+  Bitmask prereq,        /* Prerequisites of the new entry */
+  LogEst rRun,           /* Run-cost of the new entry */
+  LogEst nOut            /* Number of outputs for the new entry */
+){
+  u16 i;
+  WhereOrCost *p;
+  for(i=pSet->n, p=pSet->a; i>0; i--, p++){
+    if( rRun<=p->rRun && (prereq & p->prereq)==prereq ){
+      goto whereOrInsert_done;
+    }
+    if( p->rRun<=rRun && (p->prereq & prereq)==p->prereq ){
+      return 0;
+    }
+  }
+  if( pSet->n<N_OR_COST ){
+    p = &pSet->a[pSet->n++];
+    p->nOut = nOut;
+  }else{
+    p = pSet->a;
+    for(i=1; i<pSet->n; i++){
+      if( p->rRun>pSet->a[i].rRun ) p = pSet->a + i;
+    }
+    if( p->rRun<=rRun ) return 0;
+  }
+whereOrInsert_done:
+  p->prereq = prereq;
+  p->rRun = rRun;
+  if( p->nOut>nOut ) p->nOut = nOut;
+  return 1;
+}
+
+/*
+** Return the bitmask for the given cursor number.  Return 0 if
+** iCursor is not in the set.
+*/
+SQLITE_PRIVATE Bitmask sqlite3WhereGetMask(WhereMaskSet *pMaskSet, int iCursor){
+  int i;
+  assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 );
+  assert( pMaskSet->n>0 || pMaskSet->ix[0]<0 );
+  assert( iCursor>=-1 );
+  if( pMaskSet->ix[0]==iCursor ){
+    return 1;
+  }
+  for(i=1; i<pMaskSet->n; i++){
+    if( pMaskSet->ix[i]==iCursor ){
+      return MASKBIT(i);
+    }
+  }
+  return 0;
+}
+
+/* Allocate memory that is automatically freed when pWInfo is freed.
+*/
+SQLITE_PRIVATE void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte){
+  WhereMemBlock *pBlock;
+  pBlock = sqlite3DbMallocRawNN(pWInfo->pParse->db, nByte+sizeof(*pBlock));
+  if( pBlock ){
+    pBlock->pNext = pWInfo->pMemToFree;
+    pBlock->sz = nByte;
+    pWInfo->pMemToFree = pBlock;
+    pBlock++;
+  }
+  return (void*)pBlock;
+}
+SQLITE_PRIVATE void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte){
+  void *pNew = sqlite3WhereMalloc(pWInfo, nByte);
+  if( pNew && pOld ){
+    WhereMemBlock *pOldBlk = (WhereMemBlock*)pOld;
+    pOldBlk--;
+    assert( pOldBlk->sz<nByte );
+    memcpy(pNew, pOld, pOldBlk->sz);
+  }
+  return pNew;
+}
+
+/*
+** Create a new mask for cursor iCursor.
+**
+** There is one cursor per table in the FROM clause.  The number of
+** tables in the FROM clause is limited by a test early in the
+** sqlite3WhereBegin() routine.  So we know that the pMaskSet->ix[]
+** array will never overflow.
+*/
+static void createMask(WhereMaskSet *pMaskSet, int iCursor){
+  assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
+  pMaskSet->ix[pMaskSet->n++] = iCursor;
+}
+
+/*
+** If the right-hand branch of the expression is a TK_COLUMN, then return
+** a pointer to the right-hand branch.  Otherwise, return NULL.
+*/
+static Expr *whereRightSubexprIsColumn(Expr *p){
+  p = sqlite3ExprSkipCollateAndLikely(p->pRight);
+  if( ALWAYS(p!=0) && p->op==TK_COLUMN && !ExprHasProperty(p, EP_FixedCol) ){
+    return p;
+  }
+  return 0;
+}
+
+/*
+** Term pTerm is guaranteed to be a WO_IN term. It may be a component term
+** of a vector IN expression of the form "(x, y, ...) IN (SELECT ...)".
+** This function checks to see if the term is compatible with an index
+** column with affinity idxaff (one of the SQLITE_AFF_XYZ values). If so,
+** it returns a pointer to the name of the collation sequence (e.g. "BINARY"
+** or "NOCASE") used by the comparison in pTerm. If it is not compatible
+** with affinity idxaff, NULL is returned.
+*/
+static SQLITE_NOINLINE const char *indexInAffinityOk(
+  Parse *pParse,
+  WhereTerm *pTerm,
+  u8 idxaff
+){
+  Expr *pX = pTerm->pExpr;
+  Expr inexpr;
+
+  assert( pTerm->eOperator & WO_IN );
+
+  if( sqlite3ExprIsVector(pX->pLeft) ){
+    int iField = pTerm->u.x.iField - 1;
+    inexpr.flags = 0;
+    inexpr.op = TK_EQ;
+    inexpr.pLeft = pX->pLeft->x.pList->a[iField].pExpr;
+    assert( ExprUseXSelect(pX) );
+    inexpr.pRight = pX->x.pSelect->pEList->a[iField].pExpr;
+    pX = &inexpr;
+  }
+
+  if( sqlite3IndexAffinityOk(pX, idxaff) ){
+    CollSeq *pRet = sqlite3ExprCompareCollSeq(pParse, pX);
+    return pRet ? pRet->zName : sqlite3StrBINARY;
+  }
+  return 0;
+}
+
+/*
+** Advance to the next WhereTerm that matches according to the criteria
+** established when the pScan object was initialized by whereScanInit().
+** Return NULL if there are no more matching WhereTerms.
+*/
+static WhereTerm *whereScanNext(WhereScan *pScan){
+  int iCur;            /* The cursor on the LHS of the term */
+  i16 iColumn;         /* The column on the LHS of the term.  -1 for IPK */
+  Expr *pX;            /* An expression being tested */
+  WhereClause *pWC;    /* Shorthand for pScan->pWC */
+  WhereTerm *pTerm;    /* The term being tested */
+  int k = pScan->k;    /* Where to start scanning */
+
+  assert( pScan->iEquiv<=pScan->nEquiv );
+  pWC = pScan->pWC;
+  while(1){
+    iColumn = pScan->aiColumn[pScan->iEquiv-1];
+    iCur = pScan->aiCur[pScan->iEquiv-1];
+    assert( pWC!=0 );
+    assert( iCur>=0 );
+    do{
+      for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
+        assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 || pTerm->leftCursor<0 );
+        if( pTerm->leftCursor==iCur
+         && pTerm->u.x.leftColumn==iColumn
+         && (iColumn!=XN_EXPR
+             || sqlite3ExprCompareSkip(pTerm->pExpr->pLeft,
+                                       pScan->pIdxExpr,iCur)==0)
+         && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_OuterON))
+        ){
+          if( (pTerm->eOperator & WO_EQUIV)!=0
+           && pScan->nEquiv<ArraySize(pScan->aiCur)
+           && (pX = whereRightSubexprIsColumn(pTerm->pExpr))!=0
+          ){
+            int j;
+            for(j=0; j<pScan->nEquiv; j++){
+              if( pScan->aiCur[j]==pX->iTable
+               && pScan->aiColumn[j]==pX->iColumn ){
+                  break;
+              }
+            }
+            if( j==pScan->nEquiv ){
+              pScan->aiCur[j] = pX->iTable;
+              pScan->aiColumn[j] = pX->iColumn;
+              pScan->nEquiv++;
+            }
+          }
+          if( (pTerm->eOperator & pScan->opMask)!=0 ){
+            /* Verify the affinity and collating sequence match */
+            if( pScan->zCollName && (pTerm->eOperator & WO_ISNULL)==0 ){
+              const char *zCollName;
+              Parse *pParse = pWC->pWInfo->pParse;
+              pX = pTerm->pExpr;
+
+              if( (pTerm->eOperator & WO_IN) ){
+                zCollName = indexInAffinityOk(pParse, pTerm, pScan->idxaff);
+                if( !zCollName ) continue;
+              }else{
+                CollSeq *pColl;
+                if( !sqlite3IndexAffinityOk(pX, pScan->idxaff) ){
+                  continue;
+                }
+                assert(pX->pLeft);
+                pColl = sqlite3ExprCompareCollSeq(pParse, pX);
+                zCollName = pColl ? pColl->zName : sqlite3StrBINARY;
+              }
+
+              if( sqlite3StrICmp(zCollName, pScan->zCollName) ){
+                continue;
+              }
+            }
+            if( (pTerm->eOperator & (WO_EQ|WO_IS))!=0
+             && (pX = pTerm->pExpr->pRight, ALWAYS(pX!=0))
+             && pX->op==TK_COLUMN
+             && pX->iTable==pScan->aiCur[0]
+             && pX->iColumn==pScan->aiColumn[0]
+            ){
+              testcase( pTerm->eOperator & WO_IS );
+              continue;
+            }
+            pScan->pWC = pWC;
+            pScan->k = k+1;
+#ifdef WHERETRACE_ENABLED
+            if( sqlite3WhereTrace & 0x20000 ){
+              int ii;
+              sqlite3DebugPrintf("SCAN-TERM %p: nEquiv=%d",
+                 pTerm, pScan->nEquiv);
+              for(ii=0; ii<pScan->nEquiv; ii++){
+                sqlite3DebugPrintf(" {%d:%d}",
+                   pScan->aiCur[ii], pScan->aiColumn[ii]);
+              }
+              sqlite3DebugPrintf("\n");
+            }
+#endif
+            return pTerm;
+          }
+        }
+      }
+      pWC = pWC->pOuter;
+      k = 0;
+    }while( pWC!=0 );
+    if( pScan->iEquiv>=pScan->nEquiv ) break;
+    pWC = pScan->pOrigWC;
+    k = 0;
+    pScan->iEquiv++;
+  }
+  return 0;
+}
+
+/*
+** This is whereScanInit() for the case of an index on an expression.
+** It is factored out into a separate tail-recursion subroutine so that
+** the normal whereScanInit() routine, which is a high-runner, does not
+** need to push registers onto the stack as part of its prologue.
+*/
+static SQLITE_NOINLINE WhereTerm *whereScanInitIndexExpr(WhereScan *pScan){
+  pScan->idxaff = sqlite3ExprAffinity(pScan->pIdxExpr);
+  return whereScanNext(pScan);
+}
+
+/*
+** Initialize a WHERE clause scanner object.  Return a pointer to the
+** first match.  Return NULL if there are no matches.
+**
+** The scanner will be searching the WHERE clause pWC.  It will look
+** for terms of the form "X <op> <expr>" where X is column iColumn of table
+** iCur.   Or if pIdx!=0 then X is column iColumn of index pIdx.  pIdx
+** must be one of the indexes of table iCur.
+**
+** The <op> must be one of the operators described by opMask.
+**
+** If the search is for X and the WHERE clause contains terms of the
+** form X=Y then this routine might also return terms of the form
+** "Y <op> <expr>".  The number of levels of transitivity is limited,
+** but is enough to handle most commonly occurring SQL statements.
+**
+** If X is not the INTEGER PRIMARY KEY then X must be compatible with
+** index pIdx.
+*/
+static WhereTerm *whereScanInit(
+  WhereScan *pScan,       /* The WhereScan object being initialized */
+  WhereClause *pWC,       /* The WHERE clause to be scanned */
+  int iCur,               /* Cursor to scan for */
+  int iColumn,            /* Column to scan for */
+  u32 opMask,             /* Operator(s) to scan for */
+  Index *pIdx             /* Must be compatible with this index */
+){
+  pScan->pOrigWC = pWC;
+  pScan->pWC = pWC;
+  pScan->pIdxExpr = 0;
+  pScan->idxaff = 0;
+  pScan->zCollName = 0;
+  pScan->opMask = opMask;
+  pScan->k = 0;
+  pScan->aiCur[0] = iCur;
+  pScan->nEquiv = 1;
+  pScan->iEquiv = 1;
+  if( pIdx ){
+    int j = iColumn;
+    iColumn = pIdx->aiColumn[j];
+    if( iColumn==pIdx->pTable->iPKey ){
+      iColumn = XN_ROWID;
+    }else if( iColumn>=0 ){
+      pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity;
+      pScan->zCollName = pIdx->azColl[j];
+    }else if( iColumn==XN_EXPR ){
+      pScan->pIdxExpr = pIdx->aColExpr->a[j].pExpr;
+      pScan->zCollName = pIdx->azColl[j];
+      pScan->aiColumn[0] = XN_EXPR;
+      return whereScanInitIndexExpr(pScan);
+    }
+  }else if( iColumn==XN_EXPR ){
+    return 0;
+  }
+  pScan->aiColumn[0] = iColumn;
+  return whereScanNext(pScan);
+}
+
+/*
+** Search for a term in the WHERE clause that is of the form "X <op> <expr>"
+** where X is a reference to the iColumn of table iCur or of index pIdx
+** if pIdx!=0 and <op> is one of the WO_xx operator codes specified by
+** the op parameter.  Return a pointer to the term.  Return 0 if not found.
+**
+** If pIdx!=0 then it must be one of the indexes of table iCur.
+** Search for terms matching the iColumn-th column of pIdx
+** rather than the iColumn-th column of table iCur.
+**
+** The term returned might by Y=<expr> if there is another constraint in
+** the WHERE clause that specifies that X=Y.  Any such constraints will be
+** identified by the WO_EQUIV bit in the pTerm->eOperator field.  The
+** aiCur[]/iaColumn[] arrays hold X and all its equivalents. There are 11
+** slots in aiCur[]/aiColumn[] so that means we can look for X plus up to 10
+** other equivalent values.  Hence a search for X will return <expr> if X=A1
+** and A1=A2 and A2=A3 and ... and A9=A10 and A10=<expr>.
+**
+** If there are multiple terms in the WHERE clause of the form "X <op> <expr>"
+** then try for the one with no dependencies on <expr> - in other words where
+** <expr> is a constant expression of some kind.  Only return entries of
+** the form "X <op> Y" where Y is a column in another table if no terms of
+** the form "X <op> <const-expr>" exist.   If no terms with a constant RHS
+** exist, try to return a term that does not use WO_EQUIV.
+*/
+SQLITE_PRIVATE WhereTerm *sqlite3WhereFindTerm(
+  WhereClause *pWC,     /* The WHERE clause to be searched */
+  int iCur,             /* Cursor number of LHS */
+  int iColumn,          /* Column number of LHS */
+  Bitmask notReady,     /* RHS must not overlap with this mask */
+  u32 op,               /* Mask of WO_xx values describing operator */
+  Index *pIdx           /* Must be compatible with this index, if not NULL */
+){
+  WhereTerm *pResult = 0;
+  WhereTerm *p;
+  WhereScan scan;
+
+  p = whereScanInit(&scan, pWC, iCur, iColumn, op, pIdx);
+  op &= WO_EQ|WO_IS;
+  while( p ){
+    if( (p->prereqRight & notReady)==0 ){
+      if( p->prereqRight==0 && (p->eOperator&op)!=0 ){
+        testcase( p->eOperator & WO_IS );
+        return p;
+      }
+      if( pResult==0 ) pResult = p;
+    }
+    p = whereScanNext(&scan);
+  }
+  return pResult;
+}
+
+/*
+** This function searches pList for an entry that matches the iCol-th column
+** of index pIdx.
+**
+** If such an expression is found, its index in pList->a[] is returned. If
+** no expression is found, -1 is returned.
+*/
+static int findIndexCol(
+  Parse *pParse,                  /* Parse context */
+  ExprList *pList,                /* Expression list to search */
+  int iBase,                      /* Cursor for table associated with pIdx */
+  Index *pIdx,                    /* Index to match column of */
+  int iCol                        /* Column of index to match */
+){
+  int i;
+  const char *zColl = pIdx->azColl[iCol];
+
+  for(i=0; i<pList->nExpr; i++){
+    Expr *p = sqlite3ExprSkipCollateAndLikely(pList->a[i].pExpr);
+    if( ALWAYS(p!=0)
+     && (p->op==TK_COLUMN || p->op==TK_AGG_COLUMN)
+     && p->iColumn==pIdx->aiColumn[iCol]
+     && p->iTable==iBase
+    ){
+      CollSeq *pColl = sqlite3ExprNNCollSeq(pParse, pList->a[i].pExpr);
+      if( 0==sqlite3StrICmp(pColl->zName, zColl) ){
+        return i;
+      }
+    }
+  }
+
+  return -1;
+}
+
+/*
+** Return TRUE if the iCol-th column of index pIdx is NOT NULL
+*/
+static int indexColumnNotNull(Index *pIdx, int iCol){
+  int j;
+  assert( pIdx!=0 );
+  assert( iCol>=0 && iCol<pIdx->nColumn );
+  j = pIdx->aiColumn[iCol];
+  if( j>=0 ){
+    return pIdx->pTable->aCol[j].notNull;
+  }else if( j==(-1) ){
+    return 1;
+  }else{
+    assert( j==(-2) );
+    return 0;  /* Assume an indexed expression can always yield a NULL */
+
+  }
+}
+
+/*
+** Return true if the DISTINCT expression-list passed as the third argument
+** is redundant.
+**
+** A DISTINCT list is redundant if any subset of the columns in the
+** DISTINCT list are collectively unique and individually non-null.
+*/
+static int isDistinctRedundant(
+  Parse *pParse,            /* Parsing context */
+  SrcList *pTabList,        /* The FROM clause */
+  WhereClause *pWC,         /* The WHERE clause */
+  ExprList *pDistinct       /* The result set that needs to be DISTINCT */
+){
+  Table *pTab;
+  Index *pIdx;
+  int i;
+  int iBase;
+
+  /* If there is more than one table or sub-select in the FROM clause of
+  ** this query, then it will not be possible to show that the DISTINCT
+  ** clause is redundant. */
+  if( pTabList->nSrc!=1 ) return 0;
+  iBase = pTabList->a[0].iCursor;
+  pTab = pTabList->a[0].pSTab;
+
+  /* If any of the expressions is an IPK column on table iBase, then return
+  ** true. Note: The (p->iTable==iBase) part of this test may be false if the
+  ** current SELECT is a correlated sub-query.
+  */
+  for(i=0; i<pDistinct->nExpr; i++){
+    Expr *p = sqlite3ExprSkipCollateAndLikely(pDistinct->a[i].pExpr);
+    if( NEVER(p==0) ) continue;
+    if( p->op!=TK_COLUMN && p->op!=TK_AGG_COLUMN ) continue;
+    if( p->iTable==iBase && p->iColumn<0 ) return 1;
+  }
+
+  /* Loop through all indices on the table, checking each to see if it makes
+  ** the DISTINCT qualifier redundant. It does so if:
+  **
+  **   1. The index is itself UNIQUE, and
+  **
+  **   2. All of the columns in the index are either part of the pDistinct
+  **      list, or else the WHERE clause contains a term of the form "col=X",
+  **      where X is a constant value. The collation sequences of the
+  **      comparison and select-list expressions must match those of the index.
+  **
+  **   3. All of those index columns for which the WHERE clause does not
+  **      contain a "col=X" term are subject to a NOT NULL constraint.
+  */
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    if( !IsUniqueIndex(pIdx) ) continue;
+    if( pIdx->pPartIdxWhere ) continue;
+    for(i=0; i<pIdx->nKeyCol; i++){
+      if( 0==sqlite3WhereFindTerm(pWC, iBase, i, ~(Bitmask)0, WO_EQ, pIdx) ){
+        if( findIndexCol(pParse, pDistinct, iBase, pIdx, i)<0 ) break;
+        if( indexColumnNotNull(pIdx, i)==0 ) break;
+      }
+    }
+    if( i==pIdx->nKeyCol ){
+      /* This index implies that the DISTINCT qualifier is redundant. */
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
+
+/*
+** Estimate the logarithm of the input value to base 2.
+*/
+static LogEst estLog(LogEst N){
+  return N<=10 ? 0 : sqlite3LogEst(N) - 33;
+}
+
+/*
+** Convert OP_Column opcodes to OP_Copy in previously generated code.
+**
+** This routine runs over generated VDBE code and translates OP_Column
+** opcodes into OP_Copy when the table is being accessed via co-routine
+** instead of via table lookup.
+**
+** If the iAutoidxCur is not zero, then any OP_Rowid instructions on
+** cursor iTabCur are transformed into OP_Sequence opcode for the
+** iAutoidxCur cursor, in order to generate unique rowids for the
+** automatic index being generated.
+*/
+static void translateColumnToCopy(
+  Parse *pParse,      /* Parsing context */
+  int iStart,         /* Translate from this opcode to the end */
+  int iTabCur,        /* OP_Column/OP_Rowid references to this table */
+  int iRegister,      /* The first column is in this register */
+  int iAutoidxCur     /* If non-zero, cursor of autoindex being generated */
+){
+  Vdbe *v = pParse->pVdbe;
+  VdbeOp *pOp = sqlite3VdbeGetOp(v, iStart);
+  int iEnd = sqlite3VdbeCurrentAddr(v);
+  if( pParse->db->mallocFailed ) return;
+#ifdef SQLITE_DEBUG
+  if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
+    printf("CHECKING for column-to-copy on cursor %d for %d..%d\n",
+            iTabCur, iStart, iEnd);
+  }
+#endif
+  for(; iStart<iEnd; iStart++, pOp++){
+    if( pOp->p1!=iTabCur ) continue;
+    if( pOp->opcode==OP_Column ){
+#ifdef SQLITE_DEBUG
+      if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
+        printf("TRANSLATE OP_Column to OP_Copy at %d\n", iStart);
+      }
+#endif
+      pOp->opcode = OP_Copy;
+      pOp->p1 = pOp->p2 + iRegister;
+      pOp->p2 = pOp->p3;
+      pOp->p3 = 0;
+      pOp->p5 = 2;  /* Cause the MEM_Subtype flag to be cleared */
+    }else if( pOp->opcode==OP_Rowid ){
+#ifdef SQLITE_DEBUG
+      if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
+        printf("TRANSLATE OP_Rowid to OP_Sequence at %d\n", iStart);
+      }
+#endif
+      pOp->opcode = OP_Sequence;
+      pOp->p1 = iAutoidxCur;
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+      if( iAutoidxCur==0 ){
+        pOp->opcode = OP_Null;
+        pOp->p3 = 0;
+      }
+#endif
+    }
+  }
+}
+
+/*
+** Two routines for printing the content of an sqlite3_index_info
+** structure.  Used for testing and debugging only.  If neither
+** SQLITE_TEST or SQLITE_DEBUG are defined, then these routines
+** are no-ops.
+*/
+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(WHERETRACE_ENABLED)
+static void whereTraceIndexInfoInputs(
+  sqlite3_index_info *p,   /* The IndexInfo object */
+  Table *pTab              /* The TABLE that is the virtual table */
+){
+  int i;
+  if( (sqlite3WhereTrace & 0x10)==0 ) return;
+  sqlite3DebugPrintf("sqlite3_index_info inputs for %s:\n", pTab->zName);
+  for(i=0; i<p->nConstraint; i++){
+    sqlite3DebugPrintf(
+       "  constraint[%d]: col=%d termid=%d op=%d usabled=%d collseq=%s\n",
+       i,
+       p->aConstraint[i].iColumn,
+       p->aConstraint[i].iTermOffset,
+       p->aConstraint[i].op,
+       p->aConstraint[i].usable,
+       sqlite3_vtab_collation(p,i));
+  }
+  for(i=0; i<p->nOrderBy; i++){
+    sqlite3DebugPrintf("  orderby[%d]: col=%d desc=%d\n",
+       i,
+       p->aOrderBy[i].iColumn,
+       p->aOrderBy[i].desc);
+  }
+}
+static void whereTraceIndexInfoOutputs(
+  sqlite3_index_info *p,   /* The IndexInfo object */
+  Table *pTab              /* The TABLE that is the virtual table */
+){
+  int i;
+  if( (sqlite3WhereTrace & 0x10)==0 ) return;
+  sqlite3DebugPrintf("sqlite3_index_info outputs for %s:\n", pTab->zName);
+  for(i=0; i<p->nConstraint; i++){
+    sqlite3DebugPrintf("  usage[%d]: argvIdx=%d omit=%d\n",
+       i,
+       p->aConstraintUsage[i].argvIndex,
+       p->aConstraintUsage[i].omit);
+  }
+  sqlite3DebugPrintf("  idxNum=%d\n", p->idxNum);
+  sqlite3DebugPrintf("  idxStr=%s\n", p->idxStr);
+  sqlite3DebugPrintf("  orderByConsumed=%d\n", p->orderByConsumed);
+  sqlite3DebugPrintf("  estimatedCost=%g\n", p->estimatedCost);
+  sqlite3DebugPrintf("  estimatedRows=%lld\n", p->estimatedRows);
+}
+#else
+#define whereTraceIndexInfoInputs(A,B)
+#define whereTraceIndexInfoOutputs(A,B)
+#endif
+
+/*
+** We know that pSrc is an operand of an outer join.  Return true if
+** pTerm is a constraint that is compatible with that join.
+**
+** pTerm must be EP_OuterON if pSrc is the right operand of an
+** outer join.  pTerm can be either EP_OuterON or EP_InnerON if pSrc
+** is the left operand of a RIGHT join.
+**
+** See https://sqlite.org/forum/forumpost/206d99a16dd9212f
+** for an example of a WHERE clause constraints that may not be used on
+** the right table of a RIGHT JOIN because the constraint implies a
+** not-NULL condition on the left table of the RIGHT JOIN.
+*/
+static int constraintCompatibleWithOuterJoin(
+  const WhereTerm *pTerm,       /* WHERE clause term to check */
+  const SrcItem *pSrc           /* Table we are trying to access */
+){
+  assert( (pSrc->fg.jointype&(JT_LEFT|JT_LTORJ|JT_RIGHT))!=0 ); /* By caller */
+  testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LEFT );
+  testcase( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))==JT_LTORJ );
+  testcase( ExprHasProperty(pTerm->pExpr, EP_OuterON) )
+  testcase( ExprHasProperty(pTerm->pExpr, EP_InnerON) );
+  if( !ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON)
+   || pTerm->pExpr->w.iJoin != pSrc->iCursor
+  ){
+    return 0;
+  }
+  if( (pSrc->fg.jointype & (JT_LEFT|JT_RIGHT))!=0
+   && NEVER(ExprHasProperty(pTerm->pExpr, EP_InnerON))
+  ){
+    return 0;
+  }
+  return 1;
+}
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+/*
+** Return true if column iCol of table pTab seem like it might be a
+** good column to use as part of a query-time index.
+**
+** Current algorithm (subject to improvement!):
+**
+**   1.   If iCol is already the left-most column of some other index,
+**        then return false.
+**
+**   2.   If iCol is part of an existing index that has an aiRowLogEst of
+**        more than 20, then return false.
+**
+**   3.   If no disqualifying conditions above are found, return true.
+**
+** 2025-01-03: I experimented with a new rule that returns false if the
+** the datatype of the column is "BOOLEAN". This did not improve
+** performance on any queries at hand, but it did burn CPU cycles, so the
+** idea was not committed.
+*/
+static SQLITE_NOINLINE int columnIsGoodIndexCandidate(
+  const Table *pTab,
+  int iCol
+){
+  const Index *pIdx;
+  for(pIdx = pTab->pIndex; pIdx!=0; pIdx=pIdx->pNext){
+    int j;
+    for(j=0; j<pIdx->nKeyCol; j++){
+       if( pIdx->aiColumn[j]==iCol ){
+         if( j==0 ) return 0;
+         if( pIdx->hasStat1 && pIdx->aiRowLogEst[j+1]>20 ) return 0;
+         break;
+       }
+    }
+  }
+  return 1;
+}
+#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
+
+
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+/*
+** Return TRUE if the WHERE clause term pTerm is of a form where it
+** could be used with an index to access pSrc, assuming an appropriate
+** index existed.
+*/
+static int termCanDriveIndex(
+  const WhereTerm *pTerm,        /* WHERE clause term to check */
+  const SrcItem *pSrc,           /* Table we are trying to access */
+  const Bitmask notReady         /* Tables in outer loops of the join */
+){
+  char aff;
+  int leftCol;
+
+  if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
+  if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) return 0;
+  assert( (pSrc->fg.jointype & JT_RIGHT)==0 );
+  if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
+   && !constraintCompatibleWithOuterJoin(pTerm,pSrc)
+  ){
+    return 0;  /* See https://sqlite.org/forum/forumpost/51e6959f61 */
+  }
+  if( (pTerm->prereqRight & notReady)!=0 ) return 0;
+  assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+  leftCol = pTerm->u.x.leftColumn;
+  if( leftCol<0 ) return 0;
+  aff = pSrc->pSTab->aCol[leftCol].affinity;
+  if( !sqlite3IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
+  testcase( pTerm->pExpr->op==TK_IS );
+  return columnIsGoodIndexCandidate(pSrc->pSTab, leftCol);
+}
+#endif
+
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+/*
+** Argument pIdx represents an automatic index that the current statement
+** will create and populate. Add an OP_Explain with text of the form:
+**
+**     CREATE AUTOMATIC INDEX ON <table>(<cols>) [WHERE <expr>]
+**
+** This is only required if sqlite3_stmt_scanstatus() is enabled, to
+** associate an SQLITE_SCANSTAT_NCYCLE and SQLITE_SCANSTAT_NLOOP
+** values with. In order to avoid breaking legacy code and test cases,
+** the OP_Explain is not added if this is an EXPLAIN QUERY PLAN command.
+*/
+static void explainAutomaticIndex(
+  Parse *pParse,
+  Index *pIdx,                    /* Automatic index to explain */
+  int bPartial,                   /* True if pIdx is a partial index */
+  int *pAddrExplain               /* OUT: Address of OP_Explain */
+){
+  if( IS_STMT_SCANSTATUS(pParse->db) && pParse->explain!=2 ){
+    Table *pTab = pIdx->pTable;
+    const char *zSep = "";
+    char *zText = 0;
+    int ii = 0;
+    sqlite3_str *pStr = sqlite3_str_new(pParse->db);
+    sqlite3_str_appendf(pStr,"CREATE AUTOMATIC INDEX ON %s(", pTab->zName);
+    assert( pIdx->nColumn>1 );
+    assert( pIdx->aiColumn[pIdx->nColumn-1]==XN_ROWID || !HasRowid(pTab) );
+    for(ii=0; ii<(pIdx->nColumn-1); ii++){
+      const char *zName = 0;
+      int iCol = pIdx->aiColumn[ii];
+
+      zName = pTab->aCol[iCol].zCnName;
+      sqlite3_str_appendf(pStr, "%s%s", zSep, zName);
+      zSep = ", ";
+    }
+    zText = sqlite3_str_finish(pStr);
+    if( zText==0 ){
+      sqlite3OomFault(pParse->db);
+    }else{
+      *pAddrExplain = sqlite3VdbeExplain(
+          pParse, 0, "%s)%s", zText, (bPartial ? " WHERE <expr>" : "")
+      );
+      sqlite3_free(zText);
+    }
+  }
+}
+#else
+# define explainAutomaticIndex(a,b,c,d)
+#endif
+
+/*
+** Generate code to construct the Index object for an automatic index
+** and to set up the WhereLevel object pLevel so that the code generator
+** makes use of the automatic index.
+*/
+static SQLITE_NOINLINE void constructAutomaticIndex(
+  Parse *pParse,              /* The parsing context */
+  WhereClause *pWC,           /* The WHERE clause */
+  const Bitmask notReady,     /* Mask of cursors that are not available */
+  WhereLevel *pLevel          /* Write new index here */
+){
+  int nKeyCol;                /* Number of columns in the constructed index */
+  WhereTerm *pTerm;           /* A single term of the WHERE clause */
+  WhereTerm *pWCEnd;          /* End of pWC->a[] */
+  Index *pIdx;                /* Object describing the transient index */
+  Vdbe *v;                    /* Prepared statement under construction */
+  int addrInit;               /* Address of the initialization bypass jump */
+  Table *pTable;              /* The table being indexed */
+  int addrTop;                /* Top of the index fill loop */
+  int regRecord;              /* Register holding an index record */
+  int n;                      /* Column counter */
+  int i;                      /* Loop counter */
+  int mxBitCol;               /* Maximum column in pSrc->colUsed */
+  CollSeq *pColl;             /* Collating sequence to on a column */
+  WhereLoop *pLoop;           /* The Loop object */
+  char *zNotUsed;             /* Extra space on the end of pIdx */
+  Bitmask idxCols;            /* Bitmap of columns used for indexing */
+  Bitmask extraCols;          /* Bitmap of additional columns */
+  u8 sentWarning = 0;         /* True if a warning has been issued */
+  u8 useBloomFilter = 0;      /* True to also add a Bloom filter */
+  Expr *pPartial = 0;         /* Partial Index Expression */
+  int iContinue = 0;          /* Jump here to skip excluded rows */
+  SrcList *pTabList;          /* The complete FROM clause */
+  SrcItem *pSrc;              /* The FROM clause term to get the next index */
+  int addrCounter = 0;        /* Address where integer counter is initialized */
+  int regBase;                /* Array of registers where record is assembled */
+#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
+  int addrExp = 0;            /* Address of OP_Explain */
+#endif
+
+  /* Generate code to skip over the creation and initialization of the
+  ** transient index on 2nd and subsequent iterations of the loop. */
+  v = pParse->pVdbe;
+  assert( v!=0 );
+  addrInit = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+
+  /* Count the number of columns that will be added to the index
+  ** and used to match WHERE clause constraints */
+  nKeyCol = 0;
+  pTabList = pWC->pWInfo->pTabList;
+  pSrc = &pTabList->a[pLevel->iFrom];
+  pTable = pSrc->pSTab;
+  pWCEnd = &pWC->a[pWC->nTerm];
+  pLoop = pLevel->pWLoop;
+  idxCols = 0;
+  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
+    Expr *pExpr = pTerm->pExpr;
+    /* Make the automatic index a partial index if there are terms in the
+    ** WHERE clause (or the ON clause of a LEFT join) that constrain which
+    ** rows of the target table (pSrc) that can be used. */
+    if( (pTerm->wtFlags & TERM_VIRTUAL)==0
+     && sqlite3ExprIsSingleTableConstraint(pExpr, pTabList, pLevel->iFrom, 0)
+    ){
+      pPartial = sqlite3ExprAnd(pParse, pPartial,
+                                sqlite3ExprDup(pParse->db, pExpr, 0));
+    }
+    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
+      int iCol;
+      Bitmask cMask;
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      iCol = pTerm->u.x.leftColumn;
+      cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
+      testcase( iCol==BMS );
+      testcase( iCol==BMS-1 );
+      if( !sentWarning ){
+        sqlite3_log(SQLITE_WARNING_AUTOINDEX,
+            "automatic index on %s(%s)", pTable->zName,
+            pTable->aCol[iCol].zCnName);
+        sentWarning = 1;
+      }
+      if( (idxCols & cMask)==0 ){
+        if( whereLoopResize(pParse->db, pLoop, nKeyCol+1) ){
+          goto end_auto_index_create;
+        }
+        pLoop->aLTerm[nKeyCol++] = pTerm;
+        idxCols |= cMask;
+      }
+    }
+  }
+  assert( nKeyCol>0 || pParse->db->mallocFailed );
+  pLoop->u.btree.nEq = pLoop->nLTerm = nKeyCol;
+  pLoop->wsFlags = WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WHERE_INDEXED
+                     | WHERE_AUTO_INDEX;
+
+  /* Count the number of additional columns needed to create a
+  ** covering index.  A "covering index" is an index that contains all
+  ** columns that are needed by the query.  With a covering index, the
+  ** original table never needs to be accessed.  Automatic indices must
+  ** be a covering index because the index will not be updated if the
+  ** original table changes and the index and table cannot both be used
+  ** if they go out of sync.
+  */
+  if( IsView(pTable) ){
+    extraCols = ALLBITS & ~idxCols;
+  }else{
+    extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1));
+  }
+  if( !HasRowid(pTable) ){
+    /* For WITHOUT ROWID tables, ensure that all PRIMARY KEY columns are
+    ** either in the idxCols mask or in the extraCols mask */
+    for(i=0; i<pTable->nCol; i++){
+      if( (pTable->aCol[i].colFlags & COLFLAG_PRIMKEY)==0 ) continue;
+      if( i>=BMS-1 ){
+        extraCols |= MASKBIT(BMS-1);
+        break;
+      }
+      if( idxCols & MASKBIT(i) ) continue;
+      extraCols |= MASKBIT(i);
+    }
+  }
+  mxBitCol = MIN(BMS-1,pTable->nCol);
+  testcase( pTable->nCol==BMS-1 );
+  testcase( pTable->nCol==BMS-2 );
+  for(i=0; i<mxBitCol; i++){
+    if( extraCols & MASKBIT(i) ) nKeyCol++;
+  }
+  if( pSrc->colUsed & MASKBIT(BMS-1) ){
+    nKeyCol += pTable->nCol - BMS + 1;
+  }
+
+  /* Construct the Index object to describe this index */
+  pIdx = sqlite3AllocateIndexObject(pParse->db, nKeyCol+HasRowid(pTable),
+                                    0, &zNotUsed);
+  if( pIdx==0 ) goto end_auto_index_create;
+  pLoop->u.btree.pIndex = pIdx;
+  pIdx->zName = "auto-index";
+  pIdx->pTable = pTable;
+  n = 0;
+  idxCols = 0;
+  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
+    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
+      int iCol;
+      Bitmask cMask;
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      iCol = pTerm->u.x.leftColumn;
+      cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
+      testcase( iCol==BMS-1 );
+      testcase( iCol==BMS );
+      if( (idxCols & cMask)==0 ){
+        Expr *pX = pTerm->pExpr;
+        idxCols |= cMask;
+        pIdx->aiColumn[n] = pTerm->u.x.leftColumn;
+        pColl = sqlite3ExprCompareCollSeq(pParse, pX);
+        assert( pColl!=0 || pParse->nErr>0 ); /* TH3 collate01.800 */
+        pIdx->azColl[n] = pColl ? pColl->zName : sqlite3StrBINARY;
+        n++;
+        if( ALWAYS(pX->pLeft!=0)
+         && sqlite3ExprAffinity(pX->pLeft)!=SQLITE_AFF_TEXT
+        ){
+          /* TUNING: only use a Bloom filter on an automatic index
+          ** if one or more key columns has the ability to hold numeric
+          ** values, since strings all have the same hash in the Bloom
+          ** filter implementation and hence a Bloom filter on a text column
+          ** is not usually helpful. */
+          useBloomFilter = 1;
+        }
+      }
+    }
+  }
+  assert( (u32)n==pLoop->u.btree.nEq );
+
+  /* Add additional columns needed to make the automatic index into
+  ** a covering index */
+  for(i=0; i<mxBitCol; i++){
+    if( extraCols & MASKBIT(i) ){
+      pIdx->aiColumn[n] = i;
+      pIdx->azColl[n] = sqlite3StrBINARY;
+      n++;
+    }
+  }
+  if( pSrc->colUsed & MASKBIT(BMS-1) ){
+    for(i=BMS-1; i<pTable->nCol; i++){
+      pIdx->aiColumn[n] = i;
+      pIdx->azColl[n] = sqlite3StrBINARY;
+      n++;
+    }
+  }
+  assert( n==nKeyCol );
+  if( HasRowid(pTable) ){
+    pIdx->aiColumn[n] = XN_ROWID;
+    pIdx->azColl[n] = sqlite3StrBINARY;
+  }
+
+  /* Create the automatic index */
+  explainAutomaticIndex(pParse, pIdx, pPartial!=0, &addrExp);
+  assert( pLevel->iIdxCur>=0 );
+  pLevel->iIdxCur = pParse->nTab++;
+  sqlite3VdbeAddOp2(v, OP_OpenAutoindex, pLevel->iIdxCur, nKeyCol+1);
+  sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
+  VdbeComment((v, "for %s", pTable->zName));
+  if( OptimizationEnabled(pParse->db, SQLITE_BloomFilter) && useBloomFilter ){
+    sqlite3WhereExplainBloomFilter(pParse, pWC->pWInfo, pLevel);
+    pLevel->regFilter = ++pParse->nMem;
+    sqlite3VdbeAddOp2(v, OP_Blob, 10000, pLevel->regFilter);
+  }
+
+  /* Fill the automatic index with content */
+  assert( pSrc == &pWC->pWInfo->pTabList->a[pLevel->iFrom] );
+  if( pSrc->fg.viaCoroutine ){
+    int regYield;
+    Subquery *pSubq;
+    assert( pSrc->fg.isSubquery );
+    pSubq = pSrc->u4.pSubq;
+    assert( pSubq!=0 );
+    regYield = pSubq->regReturn;
+    addrCounter = sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
+    sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pSubq->addrFillSub);
+    addrTop =  sqlite3VdbeAddOp1(v, OP_Yield, regYield);
+    VdbeCoverage(v);
+    VdbeComment((v, "next row of %s", pSrc->pSTab->zName));
+  }else{
+    addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur); VdbeCoverage(v);
+  }
+  if( pPartial ){
+    iContinue = sqlite3VdbeMakeLabel(pParse);
+    sqlite3ExprIfFalse(pParse, pPartial, iContinue, SQLITE_JUMPIFNULL);
+    pLoop->wsFlags |= WHERE_PARTIALIDX;
+  }
+  regRecord = sqlite3GetTempReg(pParse);
+  regBase = sqlite3GenerateIndexKey(
+      pParse, pIdx, pLevel->iTabCur, regRecord, 0, 0, 0, 0
+  );
+  if( pLevel->regFilter ){
+    sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0,
+                         regBase, pLoop->u.btree.nEq);
+  }
+  sqlite3VdbeScanStatusCounters(v, addrExp, addrExp, sqlite3VdbeCurrentAddr(v));
+  sqlite3VdbeAddOp2(v, OP_IdxInsert, pLevel->iIdxCur, regRecord);
+  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
+  if( pPartial ) sqlite3VdbeResolveLabel(v, iContinue);
+  if( pSrc->fg.viaCoroutine ){
+    assert( pSrc->fg.isSubquery && pSrc->u4.pSubq!=0 );
+    sqlite3VdbeChangeP2(v, addrCounter, regBase+n);
+    testcase( pParse->db->mallocFailed );
+    assert( pLevel->iIdxCur>0 );
+    translateColumnToCopy(pParse, addrTop, pLevel->iTabCur,
+                          pSrc->u4.pSubq->regResult, pLevel->iIdxCur);
+    sqlite3VdbeGoto(v, addrTop);
+    pSrc->fg.viaCoroutine = 0;
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1); VdbeCoverage(v);
+    sqlite3VdbeChangeP5(v, SQLITE_STMTSTATUS_AUTOINDEX);
+  }
+  sqlite3VdbeJumpHere(v, addrTop);
+  sqlite3ReleaseTempReg(pParse, regRecord);
+
+  /* Jump here when skipping the initialization */
+  sqlite3VdbeJumpHere(v, addrInit);
+  sqlite3VdbeScanStatusRange(v, addrExp, addrExp, -1);
+
+end_auto_index_create:
+  sqlite3ExprDelete(pParse->db, pPartial);
+}
+#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
+
+/*
+** Generate bytecode that will initialize a Bloom filter that is appropriate
+** for pLevel.
+**
+** If there are inner loops within pLevel that have the WHERE_BLOOMFILTER
+** flag set, initialize a Bloomfilter for them as well.  Except don't do
+** this recursive initialization if the SQLITE_BloomPulldown optimization has
+** been turned off.
+**
+** When the Bloom filter is initialized, the WHERE_BLOOMFILTER flag is cleared
+** from the loop, but the regFilter value is set to a register that implements
+** the Bloom filter.  When regFilter is positive, the
+** sqlite3WhereCodeOneLoopStart() will generate code to test the Bloom filter
+** and skip the subsequence B-Tree seek if the Bloom filter indicates that
+** no matching rows exist.
+**
+** This routine may only be called if it has previously been determined that
+** the loop would benefit from a Bloom filter, and the WHERE_BLOOMFILTER bit
+** is set.
+*/
+static SQLITE_NOINLINE void sqlite3ConstructBloomFilter(
+  WhereInfo *pWInfo,    /* The WHERE clause */
+  int iLevel,           /* Index in pWInfo->a[] that is pLevel */
+  WhereLevel *pLevel,   /* Make a Bloom filter for this FROM term */
+  Bitmask notReady      /* Loops that are not ready */
+){
+  int addrOnce;                        /* Address of opening OP_Once */
+  int addrTop;                         /* Address of OP_Rewind */
+  int addrCont;                        /* Jump here to skip a row */
+  const WhereTerm *pTerm;              /* For looping over WHERE clause terms */
+  const WhereTerm *pWCEnd;             /* Last WHERE clause term */
+  Parse *pParse = pWInfo->pParse;      /* Parsing context */
+  Vdbe *v = pParse->pVdbe;             /* VDBE under construction */
+  WhereLoop *pLoop = pLevel->pWLoop;   /* The loop being coded */
+  int iCur;                            /* Cursor for table getting the filter */
+  IndexedExpr *saved_pIdxEpr;          /* saved copy of Parse.pIdxEpr */
+  IndexedExpr *saved_pIdxPartExpr;     /* saved copy of Parse.pIdxPartExpr */
+
+  saved_pIdxEpr = pParse->pIdxEpr;
+  saved_pIdxPartExpr = pParse->pIdxPartExpr;
+  pParse->pIdxEpr = 0;
+  pParse->pIdxPartExpr = 0;
+
+  assert( pLoop!=0 );
+  assert( v!=0 );
+  assert( pLoop->wsFlags & WHERE_BLOOMFILTER );
+  assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 );
+
+  addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+  do{
+    const SrcList *pTabList;
+    const SrcItem *pItem;
+    const Table *pTab;
+    u64 sz;
+    int iSrc;
+    sqlite3WhereExplainBloomFilter(pParse, pWInfo, pLevel);
+    addrCont = sqlite3VdbeMakeLabel(pParse);
+    iCur = pLevel->iTabCur;
+    pLevel->regFilter = ++pParse->nMem;
+
+    /* The Bloom filter is a Blob held in a register.  Initialize it
+    ** to zero-filled blob of at least 80K bits, but maybe more if the
+    ** estimated size of the table is larger.  We could actually
+    ** measure the size of the table at run-time using OP_Count with
+    ** P3==1 and use that value to initialize the blob.  But that makes
+    ** testing complicated.  By basing the blob size on the value in the
+    ** sqlite_stat1 table, testing is much easier.
+    */
+    pTabList = pWInfo->pTabList;
+    iSrc = pLevel->iFrom;
+    pItem = &pTabList->a[iSrc];
+    assert( pItem!=0 );
+    pTab = pItem->pSTab;
+    assert( pTab!=0 );
+    sz = sqlite3LogEstToInt(pTab->nRowLogEst);
+    if( sz<10000 ){
+      sz = 10000;
+    }else if( sz>10000000 ){
+      sz = 10000000;
+    }
+    sqlite3VdbeAddOp2(v, OP_Blob, (int)sz, pLevel->regFilter);
+
+    addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
+    pWCEnd = &pWInfo->sWC.a[pWInfo->sWC.nTerm];
+    for(pTerm=pWInfo->sWC.a; pTerm<pWCEnd; pTerm++){
+      Expr *pExpr = pTerm->pExpr;
+      if( (pTerm->wtFlags & TERM_VIRTUAL)==0
+       && sqlite3ExprIsSingleTableConstraint(pExpr, pTabList, iSrc, 0)
+      ){
+        sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
+      }
+    }
+    if( pLoop->wsFlags & WHERE_IPK ){
+      int r1 = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp2(v, OP_Rowid, iCur, r1);
+      sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, 1);
+      sqlite3ReleaseTempReg(pParse, r1);
+    }else{
+      Index *pIdx = pLoop->u.btree.pIndex;
+      int n = pLoop->u.btree.nEq;
+      int r1 = sqlite3GetTempRange(pParse, n);
+      int jj;
+      for(jj=0; jj<n; jj++){
+        assert( pIdx->pTable==pItem->pSTab );
+        sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iCur, jj, r1+jj);
+      }
+      sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pLevel->regFilter, 0, r1, n);
+      sqlite3ReleaseTempRange(pParse, r1, n);
+    }
+    sqlite3VdbeResolveLabel(v, addrCont);
+    sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1);
+    VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addrTop);
+    pLoop->wsFlags &= ~WHERE_BLOOMFILTER;
+    if( OptimizationDisabled(pParse->db, SQLITE_BloomPulldown) ) break;
+    while( ++iLevel < pWInfo->nLevel ){
+      const SrcItem *pTabItem;
+      pLevel = &pWInfo->a[iLevel];
+      pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
+      if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ) ) continue;
+      pLoop = pLevel->pWLoop;
+      if( NEVER(pLoop==0) ) continue;
+      if( pLoop->prereq & notReady ) continue;
+      if( (pLoop->wsFlags & (WHERE_BLOOMFILTER|WHERE_COLUMN_IN))
+                 ==WHERE_BLOOMFILTER
+      ){
+        /* This is a candidate for bloom-filter pull-down (early evaluation).
+        ** The test that WHERE_COLUMN_IN is omitted is important, as we are
+        ** not able to do early evaluation of bloom filters that make use of
+        ** the IN operator */
+        break;
+      }
+    }
+  }while( iLevel < pWInfo->nLevel );
+  sqlite3VdbeJumpHere(v, addrOnce);
+  pParse->pIdxEpr = saved_pIdxEpr;
+  pParse->pIdxPartExpr = saved_pIdxPartExpr;
+}
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Return term iTerm of the WhereClause passed as the first argument. Terms
+** are numbered from 0 upwards, starting with the terms in pWC->a[], then
+** those in pWC->pOuter->a[] (if any), and so on.
+*/
+static WhereTerm *termFromWhereClause(WhereClause *pWC, int iTerm){
+  WhereClause *p;
+  for(p=pWC; p; p=p->pOuter){
+    if( iTerm<p->nTerm ) return &p->a[iTerm];
+    iTerm -= p->nTerm;
+  }
+  return 0;
+}
+
+/*
+** Allocate and populate an sqlite3_index_info structure. It is the
+** responsibility of the caller to eventually release the structure
+** by passing the pointer returned by this function to freeIndexInfo().
+*/
+static sqlite3_index_info *allocateIndexInfo(
+  WhereInfo *pWInfo,              /* The WHERE clause */
+  WhereClause *pWC,               /* The WHERE clause being analyzed */
+  Bitmask mUnusable,              /* Ignore terms with these prereqs */
+  SrcItem *pSrc,                  /* The FROM clause term that is the vtab */
+  u16 *pmNoOmit                   /* Mask of terms not to omit */
+){
+  int i, j;
+  int nTerm;
+  Parse *pParse = pWInfo->pParse;
+  struct sqlite3_index_constraint *pIdxCons;
+  struct sqlite3_index_orderby *pIdxOrderBy;
+  struct sqlite3_index_constraint_usage *pUsage;
+  struct HiddenIndexInfo *pHidden;
+  WhereTerm *pTerm;
+  int nOrderBy;
+  sqlite3_index_info *pIdxInfo;
+  u16 mNoOmit = 0;
+  const Table *pTab;
+  int eDistinct = 0;
+  ExprList *pOrderBy = pWInfo->pOrderBy;
+  WhereClause *p;
+
+  assert( pSrc!=0 );
+  pTab = pSrc->pSTab;
+  assert( pTab!=0 );
+  assert( IsVirtual(pTab) );
+
+  /* Find all WHERE clause constraints referring to this virtual table.
+  ** Mark each term with the TERM_OK flag.  Set nTerm to the number of
+  ** terms found.
+  */
+  for(p=pWC, nTerm=0; p; p=p->pOuter){
+    for(i=0, pTerm=p->a; i<p->nTerm; i++, pTerm++){
+      pTerm->wtFlags &= ~TERM_OK;
+      if( pTerm->leftCursor != pSrc->iCursor ) continue;
+      if( pTerm->prereqRight & mUnusable ) continue;
+      assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
+      testcase( pTerm->eOperator & WO_IN );
+      testcase( pTerm->eOperator & WO_ISNULL );
+      testcase( pTerm->eOperator & WO_IS );
+      testcase( pTerm->eOperator & WO_ALL );
+      if( (pTerm->eOperator & ~(WO_EQUIV))==0 ) continue;
+      if( pTerm->wtFlags & TERM_VNULL ) continue;
+
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      assert( pTerm->u.x.leftColumn>=XN_ROWID );
+      assert( pTerm->u.x.leftColumn<pTab->nCol );
+      if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
+          && !constraintCompatibleWithOuterJoin(pTerm,pSrc)
+        ){
+        continue;
+      }
+      nTerm++;
+      pTerm->wtFlags |= TERM_OK;
+    }
+  }
+
+  /* If the ORDER BY clause contains only columns in the current
+  ** virtual table then allocate space for the aOrderBy part of
+  ** the sqlite3_index_info structure.
+  */
+  nOrderBy = 0;
+  if( pOrderBy ){
+    int n = pOrderBy->nExpr;
+    for(i=0; i<n; i++){
+      Expr *pExpr = pOrderBy->a[i].pExpr;
+      Expr *pE2;
+
+      /* Skip over constant terms in the ORDER BY clause */
+      if( sqlite3ExprIsConstant(0, pExpr) ){
+        continue;
+      }
+
+      /* Virtual tables are unable to deal with NULLS FIRST */
+      if( pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_BIGNULL ) break;
+
+      /* First case - a direct column references without a COLLATE operator */
+      if( pExpr->op==TK_COLUMN && pExpr->iTable==pSrc->iCursor ){
+        assert( pExpr->iColumn>=XN_ROWID && pExpr->iColumn<pTab->nCol );
+        continue;
+      }
+
+      /* 2nd case - a column reference with a COLLATE operator.  Only match
+      ** of the COLLATE operator matches the collation of the column. */
+      if( pExpr->op==TK_COLLATE
+       && (pE2 = pExpr->pLeft)->op==TK_COLUMN
+       && pE2->iTable==pSrc->iCursor
+      ){
+        const char *zColl;  /* The collating sequence name */
+        assert( !ExprHasProperty(pExpr, EP_IntValue) );
+        assert( pExpr->u.zToken!=0 );
+        assert( pE2->iColumn>=XN_ROWID && pE2->iColumn<pTab->nCol );
+        pExpr->iColumn = pE2->iColumn;
+        if( pE2->iColumn<0 ) continue;  /* Collseq does not matter for rowid */
+        zColl = sqlite3ColumnColl(&pTab->aCol[pE2->iColumn]);
+        if( zColl==0 ) zColl = sqlite3StrBINARY;
+        if( sqlite3_stricmp(pExpr->u.zToken, zColl)==0 ) continue;
+      }
+
+      /* No matches cause a break out of the loop */
+      break;
+    }
+    if( i==n ){
+      nOrderBy = n;
+      if( (pWInfo->wctrlFlags & WHERE_DISTINCTBY) && !pSrc->fg.rowidUsed ){
+        eDistinct = 2 + ((pWInfo->wctrlFlags & WHERE_SORTBYGROUP)!=0);
+      }else if( pWInfo->wctrlFlags & WHERE_GROUPBY ){
+        eDistinct = 1;
+      }
+    }
+  }
+
+  /* Allocate the sqlite3_index_info structure
+  */
+  pIdxInfo = sqlite3DbMallocZero(pParse->db, sizeof(*pIdxInfo)
+                           + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
+                           + sizeof(*pIdxOrderBy)*nOrderBy + sizeof(*pHidden)
+                           + sizeof(sqlite3_value*)*nTerm );
+  if( pIdxInfo==0 ){
+    sqlite3ErrorMsg(pParse, "out of memory");
+    return 0;
+  }
+  pHidden = (struct HiddenIndexInfo*)&pIdxInfo[1];
+  pIdxCons = (struct sqlite3_index_constraint*)&pHidden->aRhs[nTerm];
+  pIdxOrderBy = (struct sqlite3_index_orderby*)&pIdxCons[nTerm];
+  pUsage = (struct sqlite3_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
+  pIdxInfo->aConstraint = pIdxCons;
+  pIdxInfo->aOrderBy = pIdxOrderBy;
+  pIdxInfo->aConstraintUsage = pUsage;
+  pIdxInfo->colUsed = (sqlite3_int64)pSrc->colUsed;
+  if( HasRowid(pTab)==0 ){
+    /* Ensure that all bits associated with PK columns are set. This is to
+    ** ensure they are available for cases like RIGHT joins or OR loops. */
+    Index *pPk = sqlite3PrimaryKeyIndex((Table*)pTab);
+    assert( pPk!=0 );
+    for(i=0; i<pPk->nKeyCol; i++){
+      int iCol = pPk->aiColumn[i];
+      assert( iCol>=0 );
+      if( iCol>=BMS-1 ) iCol = BMS-1;
+      pIdxInfo->colUsed |= MASKBIT(iCol);
+    }
+  }
+  pHidden->pWC = pWC;
+  pHidden->pParse = pParse;
+  pHidden->eDistinct = eDistinct;
+  pHidden->mIn = 0;
+  for(p=pWC, i=j=0; p; p=p->pOuter){
+    int nLast = i+p->nTerm;;
+    for(pTerm=p->a; i<nLast; i++, pTerm++){
+      u16 op;
+      if( (pTerm->wtFlags & TERM_OK)==0 ) continue;
+      pIdxCons[j].iColumn = pTerm->u.x.leftColumn;
+      pIdxCons[j].iTermOffset = i;
+      op = pTerm->eOperator & WO_ALL;
+      if( op==WO_IN ){
+        if( (pTerm->wtFlags & TERM_SLICE)==0 ){
+          pHidden->mIn |= SMASKBIT32(j);
+        }
+        op = WO_EQ;
+      }
+      if( op==WO_AUX ){
+        pIdxCons[j].op = pTerm->eMatchOp;
+      }else if( op & (WO_ISNULL|WO_IS) ){
+        if( op==WO_ISNULL ){
+          pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_ISNULL;
+        }else{
+          pIdxCons[j].op = SQLITE_INDEX_CONSTRAINT_IS;
+        }
+      }else{
+        pIdxCons[j].op = (u8)op;
+        /* The direct assignment in the previous line is possible only because
+        ** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical.  The
+        ** following asserts verify this fact. */
+        assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ );
+        assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT );
+        assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
+        assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
+        assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
+        assert( pTerm->eOperator&(WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_AUX) );
+
+        if( op & (WO_LT|WO_LE|WO_GT|WO_GE)
+            && sqlite3ExprIsVector(pTerm->pExpr->pRight)
+          ){
+          testcase( j!=i );
+          if( j<16 ) mNoOmit |= (1 << j);
+          if( op==WO_LT ) pIdxCons[j].op = WO_LE;
+          if( op==WO_GT ) pIdxCons[j].op = WO_GE;
+        }
+      }
+
+      j++;
+    }
+  }
+  assert( j==nTerm );
+  pIdxInfo->nConstraint = j;
+  for(i=j=0; i<nOrderBy; i++){
+    Expr *pExpr = pOrderBy->a[i].pExpr;
+    if( sqlite3ExprIsConstant(0, pExpr) ) continue;
+    assert( pExpr->op==TK_COLUMN
+         || (pExpr->op==TK_COLLATE && pExpr->pLeft->op==TK_COLUMN
+              && pExpr->iColumn==pExpr->pLeft->iColumn) );
+    pIdxOrderBy[j].iColumn = pExpr->iColumn;
+    pIdxOrderBy[j].desc = pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_DESC;
+    j++;
+  }
+  pIdxInfo->nOrderBy = j;
+
+  *pmNoOmit = mNoOmit;
+  return pIdxInfo;
+}
+
+/*
+** Free and zero the sqlite3_index_info.idxStr value if needed.
+*/
+static void freeIdxStr(sqlite3_index_info *pIdxInfo){
+  if( pIdxInfo->needToFreeIdxStr ){
+    sqlite3_free(pIdxInfo->idxStr);
+    pIdxInfo->idxStr = 0;
+    pIdxInfo->needToFreeIdxStr = 0;
+  }
+}
+
+/*
+** Free an sqlite3_index_info structure allocated by allocateIndexInfo()
+** and possibly modified by xBestIndex methods.
+*/
+static void freeIndexInfo(sqlite3 *db, sqlite3_index_info *pIdxInfo){
+  HiddenIndexInfo *pHidden;
+  int i;
+  assert( pIdxInfo!=0 );
+  pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  assert( pHidden->pParse!=0 );
+  assert( pHidden->pParse->db==db );
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    sqlite3ValueFree(pHidden->aRhs[i]); /* IMP: R-14553-25174 */
+    pHidden->aRhs[i] = 0;
+  }
+  freeIdxStr(pIdxInfo);
+  sqlite3DbFree(db, pIdxInfo);
+}
+
+/*
+** The table object reference passed as the second argument to this function
+** must represent a virtual table. This function invokes the xBestIndex()
+** method of the virtual table with the sqlite3_index_info object that
+** comes in as the 3rd argument to this function.
+**
+** If an error occurs, pParse is populated with an error message and an
+** appropriate error code is returned.  A return of SQLITE_CONSTRAINT from
+** xBestIndex is not considered an error.  SQLITE_CONSTRAINT indicates that
+** the current configuration of "unusable" flags in sqlite3_index_info can
+** not result in a valid plan.
+**
+** Whether or not an error is returned, it is the responsibility of the
+** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates
+** that this is required.
+*/
+static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){
+  int rc;
+  sqlite3_vtab *pVtab;
+
+  assert( IsVirtual(pTab) );
+  pVtab = sqlite3GetVTable(pParse->db, pTab)->pVtab;
+  whereTraceIndexInfoInputs(p, pTab);
+  pParse->db->nSchemaLock++;
+  rc = pVtab->pModule->xBestIndex(pVtab, p);
+  pParse->db->nSchemaLock--;
+  whereTraceIndexInfoOutputs(p, pTab);
+
+  if( rc!=SQLITE_OK && rc!=SQLITE_CONSTRAINT ){
+    if( rc==SQLITE_NOMEM ){
+      sqlite3OomFault(pParse->db);
+    }else if( !pVtab->zErrMsg ){
+      sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc));
+    }else{
+      sqlite3ErrorMsg(pParse, "%s", pVtab->zErrMsg);
+    }
+  }
+  if( pTab->u.vtab.p->bAllSchemas ){
+    sqlite3VtabUsesAllSchemas(pParse);
+  }
+  sqlite3_free(pVtab->zErrMsg);
+  pVtab->zErrMsg = 0;
+  return rc;
+}
+#endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) */
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Estimate the location of a particular key among all keys in an
+** index.  Store the results in aStat as follows:
+**
+**    aStat[0]      Est. number of rows less than pRec
+**    aStat[1]      Est. number of rows equal to pRec
+**
+** Return the index of the sample that is the smallest sample that
+** is greater than or equal to pRec. Note that this index is not an index
+** into the aSample[] array - it is an index into a virtual set of samples
+** based on the contents of aSample[] and the number of fields in record
+** pRec.
+*/
+static int whereKeyStats(
+  Parse *pParse,              /* Database connection */
+  Index *pIdx,                /* Index to consider domain of */
+  UnpackedRecord *pRec,       /* Vector of values to consider */
+  int roundUp,                /* Round up if true.  Round down if false */
+  tRowcnt *aStat              /* OUT: stats written here */
+){
+  IndexSample *aSample = pIdx->aSample;
+  int iCol;                   /* Index of required stats in anEq[] etc. */
+  int i;                      /* Index of first sample >= pRec */
+  int iSample;                /* Smallest sample larger than or equal to pRec */
+  int iMin = 0;               /* Smallest sample not yet tested */
+  int iTest;                  /* Next sample to test */
+  int res;                    /* Result of comparison operation */
+  int nField;                 /* Number of fields in pRec */
+  tRowcnt iLower = 0;         /* anLt[] + anEq[] of largest sample pRec is > */
+
+#ifndef SQLITE_DEBUG
+  UNUSED_PARAMETER( pParse );
+#endif
+  assert( pRec!=0 );
+  assert( pIdx->nSample>0 );
+  assert( pRec->nField>0 );
+
+
+  /* Do a binary search to find the first sample greater than or equal
+  ** to pRec. If pRec contains a single field, the set of samples to search
+  ** is simply the aSample[] array. If the samples in aSample[] contain more
+  ** than one fields, all fields following the first are ignored.
+  **
+  ** If pRec contains N fields, where N is more than one, then as well as the
+  ** samples in aSample[] (truncated to N fields), the search also has to
+  ** consider prefixes of those samples. For example, if the set of samples
+  ** in aSample is:
+  **
+  **     aSample[0] = (a, 5)
+  **     aSample[1] = (a, 10)
+  **     aSample[2] = (b, 5)
+  **     aSample[3] = (c, 100)
+  **     aSample[4] = (c, 105)
+  **
+  ** Then the search space should ideally be the samples above and the
+  ** unique prefixes [a], [b] and [c]. But since that is hard to organize,
+  ** the code actually searches this set:
+  **
+  **     0: (a)
+  **     1: (a, 5)
+  **     2: (a, 10)
+  **     3: (a, 10)
+  **     4: (b)
+  **     5: (b, 5)
+  **     6: (c)
+  **     7: (c, 100)
+  **     8: (c, 105)
+  **     9: (c, 105)
+  **
+  ** For each sample in the aSample[] array, N samples are present in the
+  ** effective sample array. In the above, samples 0 and 1 are based on
+  ** sample aSample[0]. Samples 2 and 3 on aSample[1] etc.
+  **
+  ** Often, sample i of each block of N effective samples has (i+1) fields.
+  ** Except, each sample may be extended to ensure that it is greater than or
+  ** equal to the previous sample in the array. For example, in the above,
+  ** sample 2 is the first sample of a block of N samples, so at first it
+  ** appears that it should be 1 field in size. However, that would make it
+  ** smaller than sample 1, so the binary search would not work. As a result,
+  ** it is extended to two fields. The duplicates that this creates do not
+  ** cause any problems.
+  */
+  if( !HasRowid(pIdx->pTable) && IsPrimaryKeyIndex(pIdx) ){
+    nField = pIdx->nKeyCol;
+  }else{
+    nField = pIdx->nColumn;
+  }
+  nField = MIN(pRec->nField, nField);
+  iCol = 0;
+  iSample = pIdx->nSample * nField;
+  do{
+    int iSamp;                    /* Index in aSample[] of test sample */
+    int n;                        /* Number of fields in test sample */
+
+    iTest = (iMin+iSample)/2;
+    iSamp = iTest / nField;
+    if( iSamp>0 ){
+      /* The proposed effective sample is a prefix of sample aSample[iSamp].
+      ** Specifically, the shortest prefix of at least (1 + iTest%nField)
+      ** fields that is greater than the previous effective sample.  */
+      for(n=(iTest % nField) + 1; n<nField; n++){
+        if( aSample[iSamp-1].anLt[n-1]!=aSample[iSamp].anLt[n-1] ) break;
+      }
+    }else{
+      n = iTest + 1;
+    }
+
+    pRec->nField = n;
+    res = sqlite3VdbeRecordCompare(aSample[iSamp].n, aSample[iSamp].p, pRec);
+    if( res<0 ){
+      iLower = aSample[iSamp].anLt[n-1] + aSample[iSamp].anEq[n-1];
+      iMin = iTest+1;
+    }else if( res==0 && n<nField ){
+      iLower = aSample[iSamp].anLt[n-1];
+      iMin = iTest+1;
+      res = -1;
+    }else{
+      iSample = iTest;
+      iCol = n-1;
+    }
+  }while( res && iMin<iSample );
+  i = iSample / nField;
+
+#ifdef SQLITE_DEBUG
+  /* The following assert statements check that the binary search code
+  ** above found the right answer. This block serves no purpose other
+  ** than to invoke the asserts.  */
+  if( pParse->db->mallocFailed==0 ){
+    if( res==0 ){
+      /* If (res==0) is true, then pRec must be equal to sample i. */
+      assert( i<pIdx->nSample );
+      assert( iCol==nField-1 );
+      pRec->nField = nField;
+      assert( 0==sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)
+           || pParse->db->mallocFailed
+      );
+    }else{
+      /* Unless i==pIdx->nSample, indicating that pRec is larger than
+      ** all samples in the aSample[] array, pRec must be smaller than the
+      ** (iCol+1) field prefix of sample i.  */
+      assert( i<=pIdx->nSample && i>=0 );
+      pRec->nField = iCol+1;
+      assert( i==pIdx->nSample
+           || sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)>0
+           || pParse->db->mallocFailed );
+
+      /* if i==0 and iCol==0, then record pRec is smaller than all samples
+      ** in the aSample[] array. Otherwise, if (iCol>0) then pRec must
+      ** be greater than or equal to the (iCol) field prefix of sample i.
+      ** If (i>0), then pRec must also be greater than sample (i-1).  */
+      if( iCol>0 ){
+        pRec->nField = iCol;
+        assert( sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)<=0
+             || pParse->db->mallocFailed || CORRUPT_DB );
+      }
+      if( i>0 ){
+        pRec->nField = nField;
+        assert( sqlite3VdbeRecordCompare(aSample[i-1].n, aSample[i-1].p, pRec)<0
+             || pParse->db->mallocFailed || CORRUPT_DB );
+      }
+    }
+  }
+#endif /* ifdef SQLITE_DEBUG */
+
+  if( res==0 ){
+    /* Record pRec is equal to sample i */
+    assert( iCol==nField-1 );
+    aStat[0] = aSample[i].anLt[iCol];
+    aStat[1] = aSample[i].anEq[iCol];
+  }else{
+    /* At this point, the (iCol+1) field prefix of aSample[i] is the first
+    ** sample that is greater than pRec. Or, if i==pIdx->nSample then pRec
+    ** is larger than all samples in the array. */
+    tRowcnt iUpper, iGap;
+    if( i>=pIdx->nSample ){
+      iUpper = pIdx->nRowEst0;
+    }else{
+      iUpper = aSample[i].anLt[iCol];
+    }
+
+    if( iLower>=iUpper ){
+      iGap = 0;
+    }else{
+      iGap = iUpper - iLower;
+    }
+    if( roundUp ){
+      iGap = (iGap*2)/3;
+    }else{
+      iGap = iGap/3;
+    }
+    aStat[0] = iLower + iGap;
+    aStat[1] = pIdx->aAvgEq[nField-1];
+  }
+
+  /* Restore the pRec->nField value before returning.  */
+  pRec->nField = nField;
+  return i;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+/*
+** If it is not NULL, pTerm is a term that provides an upper or lower
+** bound on a range scan. Without considering pTerm, it is estimated
+** that the scan will visit nNew rows. This function returns the number
+** estimated to be visited after taking pTerm into account.
+**
+** If the user explicitly specified a likelihood() value for this term,
+** then the return value is the likelihood multiplied by the number of
+** input rows. Otherwise, this function assumes that an "IS NOT NULL" term
+** has a likelihood of 0.50, and any other term a likelihood of 0.25.
+*/
+static LogEst whereRangeAdjust(WhereTerm *pTerm, LogEst nNew){
+  LogEst nRet = nNew;
+  if( pTerm ){
+    if( pTerm->truthProb<=0 ){
+      nRet += pTerm->truthProb;
+    }else if( (pTerm->wtFlags & TERM_VNULL)==0 ){
+      nRet -= 20;        assert( 20==sqlite3LogEst(4) );
+    }
+  }
+  return nRet;
+}
+
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Return the affinity for a single column of an index.
+*/
+SQLITE_PRIVATE char sqlite3IndexColumnAffinity(sqlite3 *db, Index *pIdx, int iCol){
+  assert( iCol>=0 && iCol<pIdx->nColumn );
+  if( !pIdx->zColAff ){
+    if( sqlite3IndexAffinityStr(db, pIdx)==0 ) return SQLITE_AFF_BLOB;
+  }
+  assert( pIdx->zColAff[iCol]!=0 );
+  return pIdx->zColAff[iCol];
+}
+#endif
+
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** This function is called to estimate the number of rows visited by a
+** range-scan on a skip-scan index. For example:
+**
+**   CREATE INDEX i1 ON t1(a, b, c);
+**   SELECT * FROM t1 WHERE a=? AND c BETWEEN ? AND ?;
+**
+** Value pLoop->nOut is currently set to the estimated number of rows
+** visited for scanning (a=? AND b=?). This function reduces that estimate
+** by some factor to account for the (c BETWEEN ? AND ?) expression based
+** on the stat4 data for the index. this scan will be performed multiple
+** times (once for each (a,b) combination that matches a=?) is dealt with
+** by the caller.
+**
+** It does this by scanning through all stat4 samples, comparing values
+** extracted from pLower and pUpper with the corresponding column in each
+** sample. If L and U are the number of samples found to be less than or
+** equal to the values extracted from pLower and pUpper respectively, and
+** N is the total number of samples, the pLoop->nOut value is adjusted
+** as follows:
+**
+**   nOut = nOut * ( min(U - L, 1) / N )
+**
+** If pLower is NULL, or a value cannot be extracted from the term, L is
+** set to zero. If pUpper is NULL, or a value cannot be extracted from it,
+** U is set to N.
+**
+** Normally, this function sets *pbDone to 1 before returning. However,
+** if no value can be extracted from either pLower or pUpper (and so the
+** estimate of the number of rows delivered remains unchanged), *pbDone
+** is left as is.
+**
+** If an error occurs, an SQLite error code is returned. Otherwise,
+** SQLITE_OK.
+*/
+static int whereRangeSkipScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  WhereTerm *pLower,   /* Lower bound on the range. ex: "x>123" Might be NULL */
+  WhereTerm *pUpper,   /* Upper bound on the range. ex: "x<455" Might be NULL */
+  WhereLoop *pLoop,    /* Update the .nOut value of this loop */
+  int *pbDone          /* Set to true if at least one expr. value extracted */
+){
+  Index *p = pLoop->u.btree.pIndex;
+  int nEq = pLoop->u.btree.nEq;
+  sqlite3 *db = pParse->db;
+  int nLower = -1;
+  int nUpper = p->nSample+1;
+  int rc = SQLITE_OK;
+  u8 aff = sqlite3IndexColumnAffinity(db, p, nEq);
+  CollSeq *pColl;
+
+  sqlite3_value *p1 = 0;          /* Value extracted from pLower */
+  sqlite3_value *p2 = 0;          /* Value extracted from pUpper */
+  sqlite3_value *pVal = 0;        /* Value extracted from record */
+
+  pColl = sqlite3LocateCollSeq(pParse, p->azColl[nEq]);
+  if( pLower ){
+    rc = sqlite3Stat4ValueFromExpr(pParse, pLower->pExpr->pRight, aff, &p1);
+    nLower = 0;
+  }
+  if( pUpper && rc==SQLITE_OK ){
+    rc = sqlite3Stat4ValueFromExpr(pParse, pUpper->pExpr->pRight, aff, &p2);
+    nUpper = p2 ? 0 : p->nSample;
+  }
+
+  if( p1 || p2 ){
+    int i;
+    int nDiff;
+    for(i=0; rc==SQLITE_OK && i<p->nSample; i++){
+      rc = sqlite3Stat4Column(db, p->aSample[i].p, p->aSample[i].n, nEq, &pVal);
+      if( rc==SQLITE_OK && p1 ){
+        int res = sqlite3MemCompare(p1, pVal, pColl);
+        if( res>=0 ) nLower++;
+      }
+      if( rc==SQLITE_OK && p2 ){
+        int res = sqlite3MemCompare(p2, pVal, pColl);
+        if( res>=0 ) nUpper++;
+      }
+    }
+    nDiff = (nUpper - nLower);
+    if( nDiff<=0 ) nDiff = 1;
+
+    /* If there is both an upper and lower bound specified, and the
+    ** comparisons indicate that they are close together, use the fallback
+    ** method (assume that the scan visits 1/64 of the rows) for estimating
+    ** the number of rows visited. Otherwise, estimate the number of rows
+    ** using the method described in the header comment for this function. */
+    if( nDiff!=1 || pUpper==0 || pLower==0 ){
+      int nAdjust = (sqlite3LogEst(p->nSample) - sqlite3LogEst(nDiff));
+      pLoop->nOut -= nAdjust;
+      *pbDone = 1;
+      WHERETRACE(0x20, ("range skip-scan regions: %u..%u  adjust=%d est=%d\n",
+                           nLower, nUpper, nAdjust*-1, pLoop->nOut));
+    }
+
+  }else{
+    assert( *pbDone==0 );
+  }
+
+  sqlite3ValueFree(p1);
+  sqlite3ValueFree(p2);
+  sqlite3ValueFree(pVal);
+
+  return rc;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+/*
+** This function is used to estimate the number of rows that will be visited
+** by scanning an index for a range of values. The range may have an upper
+** bound, a lower bound, or both. The WHERE clause terms that set the upper
+** and lower bounds are represented by pLower and pUpper respectively. For
+** example, assuming that index p is on t1(a):
+**
+**   ... FROM t1 WHERE a > ? AND a < ? ...
+**                    |_____|   |_____|
+**                       |         |
+**                     pLower    pUpper
+**
+** If either of the upper or lower bound is not present, then NULL is passed in
+** place of the corresponding WhereTerm.
+**
+** The value in (pBuilder->pNew->u.btree.nEq) is the number of the index
+** column subject to the range constraint. Or, equivalently, the number of
+** equality constraints optimized by the proposed index scan. For example,
+** assuming index p is on t1(a, b), and the SQL query is:
+**
+**   ... FROM t1 WHERE a = ? AND b > ? AND b < ? ...
+**
+** then nEq is set to 1 (as the range restricted column, b, is the second
+** left-most column of the index). Or, if the query is:
+**
+**   ... FROM t1 WHERE a > ? AND a < ? ...
+**
+** then nEq is set to 0.
+**
+** When this function is called, *pnOut is set to the sqlite3LogEst() of the
+** number of rows that the index scan is expected to visit without
+** considering the range constraints. If nEq is 0, then *pnOut is the number of
+** rows in the index. Assuming no error occurs, *pnOut is adjusted (reduced)
+** to account for the range constraints pLower and pUpper.
+**
+** In the absence of sqlite_stat4 ANALYZE data, or if such data cannot be
+** used, a single range inequality reduces the search space by a factor of 4.
+** and a pair of constraints (x>? AND x<?) reduces the expected number of
+** rows visited by a factor of 64.
+*/
+static int whereRangeScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  WhereLoopBuilder *pBuilder,
+  WhereTerm *pLower,   /* Lower bound on the range. ex: "x>123" Might be NULL */
+  WhereTerm *pUpper,   /* Upper bound on the range. ex: "x<455" Might be NULL */
+  WhereLoop *pLoop     /* Modify the .nOut and maybe .rRun fields */
+){
+  int rc = SQLITE_OK;
+  int nOut = pLoop->nOut;
+  LogEst nNew;
+
+#ifdef SQLITE_ENABLE_STAT4
+  Index *p = pLoop->u.btree.pIndex;
+  int nEq = pLoop->u.btree.nEq;
+
+  if( p->nSample>0 && ALWAYS(nEq<p->nSampleCol)
+   && OptimizationEnabled(pParse->db, SQLITE_Stat4)
+  ){
+    if( nEq==pBuilder->nRecValid ){
+      UnpackedRecord *pRec = pBuilder->pRec;
+      tRowcnt a[2];
+      int nBtm = pLoop->u.btree.nBtm;
+      int nTop = pLoop->u.btree.nTop;
+
+      /* Variable iLower will be set to the estimate of the number of rows in
+      ** the index that are less than the lower bound of the range query. The
+      ** lower bound being the concatenation of $P and $L, where $P is the
+      ** key-prefix formed by the nEq values matched against the nEq left-most
+      ** columns of the index, and $L is the value in pLower.
+      **
+      ** Or, if pLower is NULL or $L cannot be extracted from it (because it
+      ** is not a simple variable or literal value), the lower bound of the
+      ** range is $P. Due to a quirk in the way whereKeyStats() works, even
+      ** if $L is available, whereKeyStats() is called for both ($P) and
+      ** ($P:$L) and the larger of the two returned values is used.
+      **
+      ** Similarly, iUpper is to be set to the estimate of the number of rows
+      ** less than the upper bound of the range query. Where the upper bound
+      ** is either ($P) or ($P:$U). Again, even if $U is available, both values
+      ** of iUpper are requested of whereKeyStats() and the smaller used.
+      **
+      ** The number of rows between the two bounds is then just iUpper-iLower.
+      */
+      tRowcnt iLower;     /* Rows less than the lower bound */
+      tRowcnt iUpper;     /* Rows less than the upper bound */
+      int iLwrIdx = -2;   /* aSample[] for the lower bound */
+      int iUprIdx = -1;   /* aSample[] for the upper bound */
+
+      if( pRec ){
+        testcase( pRec->nField!=pBuilder->nRecValid );
+        pRec->nField = pBuilder->nRecValid;
+      }
+      /* Determine iLower and iUpper using ($P) only. */
+      if( nEq==0 ){
+        iLower = 0;
+        iUpper = p->nRowEst0;
+      }else{
+        /* Note: this call could be optimized away - since the same values must
+        ** have been requested when testing key $P in whereEqualScanEst().  */
+        whereKeyStats(pParse, p, pRec, 0, a);
+        iLower = a[0];
+        iUpper = a[0] + a[1];
+      }
+
+      assert( pLower==0 || (pLower->eOperator & (WO_GT|WO_GE))!=0 );
+      assert( pUpper==0 || (pUpper->eOperator & (WO_LT|WO_LE))!=0 );
+      assert( p->aSortOrder!=0 );
+      if( p->aSortOrder[nEq] ){
+        /* The roles of pLower and pUpper are swapped for a DESC index */
+        SWAP(WhereTerm*, pLower, pUpper);
+        SWAP(int, nBtm, nTop);
+      }
+
+      /* If possible, improve on the iLower estimate using ($P:$L). */
+      if( pLower ){
+        int n;                    /* Values extracted from pExpr */
+        Expr *pExpr = pLower->pExpr->pRight;
+        rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, nBtm, nEq, &n);
+        if( rc==SQLITE_OK && n ){
+          tRowcnt iNew;
+          u16 mask = WO_GT|WO_LE;
+          if( sqlite3ExprVectorSize(pExpr)>n ) mask = (WO_LE|WO_LT);
+          iLwrIdx = whereKeyStats(pParse, p, pRec, 0, a);
+          iNew = a[0] + ((pLower->eOperator & mask) ? a[1] : 0);
+          if( iNew>iLower ) iLower = iNew;
+          nOut--;
+          pLower = 0;
+        }
+      }
+
+      /* If possible, improve on the iUpper estimate using ($P:$U). */
+      if( pUpper ){
+        int n;                    /* Values extracted from pExpr */
+        Expr *pExpr = pUpper->pExpr->pRight;
+        rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, nTop, nEq, &n);
+        if( rc==SQLITE_OK && n ){
+          tRowcnt iNew;
+          u16 mask = WO_GT|WO_LE;
+          if( sqlite3ExprVectorSize(pExpr)>n ) mask = (WO_LE|WO_LT);
+          iUprIdx = whereKeyStats(pParse, p, pRec, 1, a);
+          iNew = a[0] + ((pUpper->eOperator & mask) ? a[1] : 0);
+          if( iNew<iUpper ) iUpper = iNew;
+          nOut--;
+          pUpper = 0;
+        }
+      }
+
+      pBuilder->pRec = pRec;
+      if( rc==SQLITE_OK ){
+        if( iUpper>iLower ){
+          nNew = sqlite3LogEst(iUpper - iLower);
+          /* TUNING:  If both iUpper and iLower are derived from the same
+          ** sample, then assume they are 4x more selective.  This brings
+          ** the estimated selectivity more in line with what it would be
+          ** if estimated without the use of STAT4 tables. */
+          if( iLwrIdx==iUprIdx ){ nNew -= 20; }
+          assert( 20==sqlite3LogEst(4) );
+        }else{
+          nNew = 10;        assert( 10==sqlite3LogEst(2) );
+        }
+        if( nNew<nOut ){
+          nOut = nNew;
+        }
+        WHERETRACE(0x20, ("STAT4 range scan: %u..%u  est=%d\n",
+                           (u32)iLower, (u32)iUpper, nOut));
+      }
+    }else{
+      int bDone = 0;
+      rc = whereRangeSkipScanEst(pParse, pLower, pUpper, pLoop, &bDone);
+      if( bDone ) return rc;
+    }
+  }
+#else
+  UNUSED_PARAMETER(pParse);
+  UNUSED_PARAMETER(pBuilder);
+  assert( pLower || pUpper );
+#endif
+  assert( pUpper==0 || (pUpper->wtFlags & TERM_VNULL)==0 || pParse->nErr>0 );
+  nNew = whereRangeAdjust(pLower, nOut);
+  nNew = whereRangeAdjust(pUpper, nNew);
+
+  /* TUNING: If there is both an upper and lower limit and neither limit
+  ** has an application-defined likelihood(), assume the range is
+  ** reduced by an additional 75%. This means that, by default, an open-ended
+  ** range query (e.g. col > ?) is assumed to match 1/4 of the rows in the
+  ** index. While a closed range (e.g. col BETWEEN ? AND ?) is estimated to
+  ** match 1/64 of the index. */
+  if( pLower && pLower->truthProb>0 && pUpper && pUpper->truthProb>0 ){
+    nNew -= 20;
+  }
+
+  nOut -= (pLower!=0) + (pUpper!=0);
+  if( nNew<10 ) nNew = 10;
+  if( nNew<nOut ) nOut = nNew;
+#if defined(WHERETRACE_ENABLED)
+  if( pLoop->nOut>nOut ){
+    WHERETRACE(0x20,("Range scan lowers nOut from %d to %d\n",
+                    pLoop->nOut, nOut));
+  }
+#endif
+  pLoop->nOut = (LogEst)nOut;
+  return rc;
+}
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Estimate the number of rows that will be returned based on
+** an equality constraint x=VALUE and where that VALUE occurs in
+** the histogram data.  This only works when x is the left-most
+** column of an index and sqlite_stat4 histogram data is available
+** for that index.  When pExpr==NULL that means the constraint is
+** "x IS NULL" instead of "x=VALUE".
+**
+** Write the estimated row count into *pnRow and return SQLITE_OK.
+** If unable to make an estimate, leave *pnRow unchanged and return
+** non-zero.
+**
+** This routine can fail if it is unable to load a collating sequence
+** required for string comparison, or if unable to allocate memory
+** for a UTF conversion required for comparison.  The error is stored
+** in the pParse structure.
+*/
+static int whereEqualScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  WhereLoopBuilder *pBuilder,
+  Expr *pExpr,         /* Expression for VALUE in the x=VALUE constraint */
+  tRowcnt *pnRow       /* Write the revised row estimate here */
+){
+  Index *p = pBuilder->pNew->u.btree.pIndex;
+  int nEq = pBuilder->pNew->u.btree.nEq;
+  UnpackedRecord *pRec = pBuilder->pRec;
+  int rc;                   /* Subfunction return code */
+  tRowcnt a[2];             /* Statistics */
+  int bOk;
+
+  assert( nEq>=1 );
+  assert( nEq<=p->nColumn );
+  assert( p->aSample!=0 );
+  assert( p->nSample>0 );
+  assert( pBuilder->nRecValid<nEq );
+
+  /* If values are not available for all fields of the index to the left
+  ** of this one, no estimate can be made. Return SQLITE_NOTFOUND. */
+  if( pBuilder->nRecValid<(nEq-1) ){
+    return SQLITE_NOTFOUND;
+  }
+
+  /* This is an optimization only. The call to sqlite3Stat4ProbeSetValue()
+  ** below would return the same value.  */
+  if( nEq>=p->nColumn ){
+    *pnRow = 1;
+    return SQLITE_OK;
+  }
+
+  rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, 1, nEq-1, &bOk);
+  pBuilder->pRec = pRec;
+  if( rc!=SQLITE_OK ) return rc;
+  if( bOk==0 ) return SQLITE_NOTFOUND;
+  pBuilder->nRecValid = nEq;
+
+  whereKeyStats(pParse, p, pRec, 0, a);
+  WHERETRACE(0x20,("equality scan regions %s(%d): %d\n",
+                   p->zName, nEq-1, (int)a[1]));
+  *pnRow = a[1];
+
+  return rc;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Estimate the number of rows that will be returned based on
+** an IN constraint where the right-hand side of the IN operator
+** is a list of values.  Example:
+**
+**        WHERE x IN (1,2,3,4)
+**
+** Write the estimated row count into *pnRow and return SQLITE_OK.
+** If unable to make an estimate, leave *pnRow unchanged and return
+** non-zero.
+**
+** This routine can fail if it is unable to load a collating sequence
+** required for string comparison, or if unable to allocate memory
+** for a UTF conversion required for comparison.  The error is stored
+** in the pParse structure.
+*/
+static int whereInScanEst(
+  Parse *pParse,       /* Parsing & code generating context */
+  WhereLoopBuilder *pBuilder,
+  ExprList *pList,     /* The value list on the RHS of "x IN (v1,v2,v3,...)" */
+  tRowcnt *pnRow       /* Write the revised row estimate here */
+){
+  Index *p = pBuilder->pNew->u.btree.pIndex;
+  i64 nRow0 = sqlite3LogEstToInt(p->aiRowLogEst[0]);
+  int nRecValid = pBuilder->nRecValid;
+  int rc = SQLITE_OK;     /* Subfunction return code */
+  tRowcnt nEst;           /* Number of rows for a single term */
+  tRowcnt nRowEst = 0;    /* New estimate of the number of rows */
+  int i;                  /* Loop counter */
+
+  assert( p->aSample!=0 );
+  for(i=0; rc==SQLITE_OK && i<pList->nExpr; i++){
+    nEst = nRow0;
+    rc = whereEqualScanEst(pParse, pBuilder, pList->a[i].pExpr, &nEst);
+    nRowEst += nEst;
+    pBuilder->nRecValid = nRecValid;
+  }
+
+  if( rc==SQLITE_OK ){
+    if( nRowEst > (tRowcnt)nRow0 ) nRowEst = nRow0;
+    *pnRow = nRowEst;
+    WHERETRACE(0x20,("IN row estimate: est=%d\n", nRowEst));
+  }
+  assert( pBuilder->nRecValid==nRecValid );
+  return rc;
+}
+#endif /* SQLITE_ENABLE_STAT4 */
+
+
+#if defined(WHERETRACE_ENABLED) || defined(SQLITE_DEBUG)
+/*
+** Print the content of a WhereTerm object
+*/
+SQLITE_PRIVATE void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm){
+  if( pTerm==0 ){
+    sqlite3DebugPrintf("TERM-%-3d NULL\n", iTerm);
+  }else{
+    char zType[8];
+    char zLeft[50];
+    memcpy(zType, "....", 5);
+    if( pTerm->wtFlags & TERM_VIRTUAL ) zType[0] = 'V';
+    if( pTerm->eOperator & WO_EQUIV  ) zType[1] = 'E';
+    if( ExprHasProperty(pTerm->pExpr, EP_OuterON) ) zType[2] = 'L';
+    if( pTerm->wtFlags & TERM_CODED  ) zType[3] = 'C';
+    if( pTerm->eOperator & WO_SINGLE ){
+      assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 );
+      sqlite3_snprintf(sizeof(zLeft),zLeft,"left={%d:%d}",
+                       pTerm->leftCursor, pTerm->u.x.leftColumn);
+    }else if( (pTerm->eOperator & WO_OR)!=0 && pTerm->u.pOrInfo!=0 ){
+      sqlite3_snprintf(sizeof(zLeft),zLeft,"indexable=0x%llx",
+                       pTerm->u.pOrInfo->indexable);
+    }else{
+      sqlite3_snprintf(sizeof(zLeft),zLeft,"left=%d", pTerm->leftCursor);
+    }
+    sqlite3DebugPrintf(
+       "TERM-%-3d %p %s %-12s op=%03x wtFlags=%04x",
+       iTerm, pTerm, zType, zLeft, pTerm->eOperator, pTerm->wtFlags);
+    /* The 0x10000 .wheretrace flag causes extra information to be
+    ** shown about each Term */
+    if( sqlite3WhereTrace & 0x10000 ){
+      sqlite3DebugPrintf(" prob=%-3d prereq=%llx,%llx",
+        pTerm->truthProb, (u64)pTerm->prereqAll, (u64)pTerm->prereqRight);
+    }
+    if( (pTerm->eOperator & (WO_OR|WO_AND))==0 && pTerm->u.x.iField ){
+      sqlite3DebugPrintf(" iField=%d", pTerm->u.x.iField);
+    }
+    if( pTerm->iParent>=0 ){
+      sqlite3DebugPrintf(" iParent=%d", pTerm->iParent);
+    }
+    sqlite3DebugPrintf("\n");
+    sqlite3TreeViewExpr(0, pTerm->pExpr, 0);
+  }
+}
+SQLITE_PRIVATE void sqlite3ShowWhereTerm(WhereTerm *pTerm){
+  sqlite3WhereTermPrint(pTerm, 0);
+}
+#endif
+
+#ifdef WHERETRACE_ENABLED
+/*
+** Show the complete content of a WhereClause
+*/
+SQLITE_PRIVATE void sqlite3WhereClausePrint(WhereClause *pWC){
+  int i;
+  for(i=0; i<pWC->nTerm; i++){
+    sqlite3WhereTermPrint(&pWC->a[i], i);
+  }
+}
+#endif
+
+#ifdef WHERETRACE_ENABLED
+/*
+** Print a WhereLoop object for debugging purposes
+**
+** Format example:
+**
+**     .--- Position in WHERE clause           rSetup, rRun, nOut ---.
+**     |                                                             |
+**     |  .--- selfMask                       nTerm ------.          |
+**     |  |                                               |          |
+**     |  |   .-- prereq    Idx          wsFlags----.     |          |
+**     |  |   |             Name                    |     |          |
+**     |  |   |           __|__        nEq ---.  ___|__   |        __|__
+**     | / \ / \         /     \              | /      \ / \      /     \
+**     1.002.001         t2.t2xy              2 f 010241 N 2 cost 0,56,31
+*/
+SQLITE_PRIVATE void sqlite3WhereLoopPrint(const WhereLoop *p, const WhereClause *pWC){
+  WhereInfo *pWInfo;
+  if( pWC ){
+    pWInfo = pWC->pWInfo;
+    int nb = 1+(pWInfo->pTabList->nSrc+3)/4;
+    SrcItem *pItem = pWInfo->pTabList->a + p->iTab;
+    Table *pTab = pItem->pSTab;
+    Bitmask mAll = (((Bitmask)1)<<(nb*4)) - 1;
+    sqlite3DebugPrintf("%c%2d.%0*llx.%0*llx", p->cId,
+                       p->iTab, nb, p->maskSelf, nb, p->prereq & mAll);
+    sqlite3DebugPrintf(" %12s",
+                       pItem->zAlias ? pItem->zAlias : pTab->zName);
+  }else{
+    pWInfo = 0;
+    sqlite3DebugPrintf("%c%2d.%03llx.%03llx %c%d",
+         p->cId, p->iTab, p->maskSelf, p->prereq & 0xfff, p->cId, p->iTab);
+  }
+  if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
+    const char *zName;
+    if( p->u.btree.pIndex && (zName = p->u.btree.pIndex->zName)!=0 ){
+      if( strncmp(zName, "sqlite_autoindex_", 17)==0 ){
+        int i = sqlite3Strlen30(zName) - 1;
+        while( zName[i]!='_' ) i--;
+        zName += i;
+      }
+      sqlite3DebugPrintf(".%-16s %2d", zName, p->u.btree.nEq);
+    }else{
+      sqlite3DebugPrintf("%20s","");
+    }
+  }else{
+    char *z;
+    if( p->u.vtab.idxStr ){
+      z = sqlite3_mprintf("(%d,\"%s\",%#x)",
+                p->u.vtab.idxNum, p->u.vtab.idxStr, p->u.vtab.omitMask);
+    }else{
+      z = sqlite3_mprintf("(%d,%x)", p->u.vtab.idxNum, p->u.vtab.omitMask);
+    }
+    sqlite3DebugPrintf(" %-19s", z);
+    sqlite3_free(z);
+  }
+  if( p->wsFlags & WHERE_SKIPSCAN ){
+    sqlite3DebugPrintf(" f %06x %d-%d", p->wsFlags, p->nLTerm,p->nSkip);
+  }else{
+    sqlite3DebugPrintf(" f %06x N %d", p->wsFlags, p->nLTerm);
+  }
+  if( pWInfo && pWInfo->bStarUsed && p->rStarDelta!=0 ){
+    sqlite3DebugPrintf(" cost %d,%d,%d delta=%d\n",
+                       p->rSetup, p->rRun, p->nOut, p->rStarDelta);
+  }else{
+    sqlite3DebugPrintf(" cost %d,%d,%d\n", p->rSetup, p->rRun, p->nOut);
+  }
+  if( p->nLTerm && (sqlite3WhereTrace & 0x4000)!=0 ){
+    int i;
+    for(i=0; i<p->nLTerm; i++){
+      sqlite3WhereTermPrint(p->aLTerm[i], i);
+    }
+  }
+}
+SQLITE_PRIVATE void sqlite3ShowWhereLoop(const WhereLoop *p){
+  if( p ) sqlite3WhereLoopPrint(p, 0);
+}
+SQLITE_PRIVATE void sqlite3ShowWhereLoopList(const WhereLoop *p){
+  while( p ){
+    sqlite3ShowWhereLoop(p);
+    p = p->pNextLoop;
+  }
+}
+#endif
+
+/*
+** Convert bulk memory into a valid WhereLoop that can be passed
+** to whereLoopClear harmlessly.
+*/
+static void whereLoopInit(WhereLoop *p){
+  p->aLTerm = p->aLTermSpace;
+  p->nLTerm = 0;
+  p->nLSlot = ArraySize(p->aLTermSpace);
+  p->wsFlags = 0;
+}
+
+/*
+** Clear the WhereLoop.u union.  Leave WhereLoop.pLTerm intact.
+*/
+static void whereLoopClearUnion(sqlite3 *db, WhereLoop *p){
+  if( p->wsFlags & (WHERE_VIRTUALTABLE|WHERE_AUTO_INDEX) ){
+    if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 && p->u.vtab.needFree ){
+      sqlite3_free(p->u.vtab.idxStr);
+      p->u.vtab.needFree = 0;
+      p->u.vtab.idxStr = 0;
+    }else if( (p->wsFlags & WHERE_AUTO_INDEX)!=0 && p->u.btree.pIndex!=0 ){
+      sqlite3DbFree(db, p->u.btree.pIndex->zColAff);
+      sqlite3DbFreeNN(db, p->u.btree.pIndex);
+      p->u.btree.pIndex = 0;
+    }
+  }
+}
+
+/*
+** Deallocate internal memory used by a WhereLoop object.  Leave the
+** object in an initialized state, as if it had been newly allocated.
+*/
+static void whereLoopClear(sqlite3 *db, WhereLoop *p){
+  if( p->aLTerm!=p->aLTermSpace ){
+    sqlite3DbFreeNN(db, p->aLTerm);
+    p->aLTerm = p->aLTermSpace;
+    p->nLSlot = ArraySize(p->aLTermSpace);
+  }
+  whereLoopClearUnion(db, p);
+  p->nLTerm = 0;
+  p->wsFlags = 0;
+}
+
+/*
+** Increase the memory allocation for pLoop->aLTerm[] to be at least n.
+*/
+static int whereLoopResize(sqlite3 *db, WhereLoop *p, int n){
+  WhereTerm **paNew;
+  if( p->nLSlot>=n ) return SQLITE_OK;
+  n = (n+7)&~7;
+  paNew = sqlite3DbMallocRawNN(db, sizeof(p->aLTerm[0])*n);
+  if( paNew==0 ) return SQLITE_NOMEM_BKPT;
+  memcpy(paNew, p->aLTerm, sizeof(p->aLTerm[0])*p->nLSlot);
+  if( p->aLTerm!=p->aLTermSpace ) sqlite3DbFreeNN(db, p->aLTerm);
+  p->aLTerm = paNew;
+  p->nLSlot = n;
+  return SQLITE_OK;
+}
+
+/*
+** Transfer content from the second pLoop into the first.
+*/
+static int whereLoopXfer(sqlite3 *db, WhereLoop *pTo, WhereLoop *pFrom){
+  whereLoopClearUnion(db, pTo);
+  if( pFrom->nLTerm > pTo->nLSlot
+   && whereLoopResize(db, pTo, pFrom->nLTerm)
+  ){
+    memset(pTo, 0, WHERE_LOOP_XFER_SZ);
+    return SQLITE_NOMEM_BKPT;
+  }
+  memcpy(pTo, pFrom, WHERE_LOOP_XFER_SZ);
+  memcpy(pTo->aLTerm, pFrom->aLTerm, pTo->nLTerm*sizeof(pTo->aLTerm[0]));
+  if( pFrom->wsFlags & WHERE_VIRTUALTABLE ){
+    pFrom->u.vtab.needFree = 0;
+  }else if( (pFrom->wsFlags & WHERE_AUTO_INDEX)!=0 ){
+    pFrom->u.btree.pIndex = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Delete a WhereLoop object
+*/
+static void whereLoopDelete(sqlite3 *db, WhereLoop *p){
+  assert( db!=0 );
+  whereLoopClear(db, p);
+  sqlite3DbNNFreeNN(db, p);
+}
+
+/*
+** Free a WhereInfo structure
+*/
+static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
+  assert( pWInfo!=0 );
+  assert( db!=0 );
+  sqlite3WhereClauseClear(&pWInfo->sWC);
+  while( pWInfo->pLoops ){
+    WhereLoop *p = pWInfo->pLoops;
+    pWInfo->pLoops = p->pNextLoop;
+    whereLoopDelete(db, p);
+  }
+  while( pWInfo->pMemToFree ){
+    WhereMemBlock *pNext = pWInfo->pMemToFree->pNext;
+    sqlite3DbNNFreeNN(db, pWInfo->pMemToFree);
+    pWInfo->pMemToFree = pNext;
+  }
+  sqlite3DbNNFreeNN(db, pWInfo);
+}
+
+/*
+** Return TRUE if X is a proper subset of Y but is of equal or less cost.
+** In other words, return true if all constraints of X are also part of Y
+** and Y has additional constraints that might speed the search that X lacks
+** but the cost of running X is not more than the cost of running Y.
+**
+** In other words, return true if the cost relationship between X and Y
+** is inverted and needs to be adjusted.
+**
+** Case 1:
+**
+**   (1a)  X and Y use the same index.
+**   (1b)  X has fewer == terms than Y
+**   (1c)  Neither X nor Y use skip-scan
+**   (1d)  X does not have a a greater cost than Y
+**
+** Case 2:
+**
+**   (2a)  X has the same or lower cost, or returns the same or fewer rows,
+**         than Y.
+**   (2b)  X uses fewer WHERE clause terms than Y
+**   (2c)  Every WHERE clause term used by X is also used by Y
+**   (2d)  X skips at least as many columns as Y
+**   (2e)  If X is a covering index, than Y is too
+*/
+static int whereLoopCheaperProperSubset(
+  const WhereLoop *pX,       /* First WhereLoop to compare */
+  const WhereLoop *pY        /* Compare against this WhereLoop */
+){
+  int i, j;
+  if( pX->rRun>pY->rRun && pX->nOut>pY->nOut ) return 0; /* (1d) and (2a) */
+  assert( (pX->wsFlags & WHERE_VIRTUALTABLE)==0 );
+  assert( (pY->wsFlags & WHERE_VIRTUALTABLE)==0 );
+  if( pX->u.btree.nEq < pY->u.btree.nEq                  /* (1b) */
+   && pX->u.btree.pIndex==pY->u.btree.pIndex             /* (1a) */
+   && pX->nSkip==0 && pY->nSkip==0                       /* (1c) */
+  ){
+    return 1;  /* Case 1 is true */
+  }
+  if( pX->nLTerm-pX->nSkip >= pY->nLTerm-pY->nSkip ){
+    return 0;                                            /* (2b) */
+  }
+  if( pY->nSkip > pX->nSkip ) return 0;                  /* (2d) */
+  for(i=pX->nLTerm-1; i>=0; i--){
+    if( pX->aLTerm[i]==0 ) continue;
+    for(j=pY->nLTerm-1; j>=0; j--){
+      if( pY->aLTerm[j]==pX->aLTerm[i] ) break;
+    }
+    if( j<0 ) return 0;                                  /* (2c) */
+  }
+  if( (pX->wsFlags&WHERE_IDX_ONLY)!=0
+   && (pY->wsFlags&WHERE_IDX_ONLY)==0 ){
+    return 0;                                            /* (2e) */
+  }
+  return 1;  /* Case 2 is true */
+}
+
+/*
+** Try to adjust the cost and number of output rows of WhereLoop pTemplate
+** upwards or downwards so that:
+**
+**   (1) pTemplate costs less than any other WhereLoops that are a proper
+**       subset of pTemplate
+**
+**   (2) pTemplate costs more than any other WhereLoops for which pTemplate
+**       is a proper subset.
+**
+** To say "WhereLoop X is a proper subset of Y" means that X uses fewer
+** WHERE clause terms than Y and that every WHERE clause term used by X is
+** also used by Y.
+*/
+static void whereLoopAdjustCost(const WhereLoop *p, WhereLoop *pTemplate){
+  if( (pTemplate->wsFlags & WHERE_INDEXED)==0 ) return;
+  for(; p; p=p->pNextLoop){
+    if( p->iTab!=pTemplate->iTab ) continue;
+    if( (p->wsFlags & WHERE_INDEXED)==0 ) continue;
+    if( whereLoopCheaperProperSubset(p, pTemplate) ){
+      /* Adjust pTemplate cost downward so that it is cheaper than its
+      ** subset p. */
+      WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n",
+                       pTemplate->rRun, pTemplate->nOut,
+                       MIN(p->rRun, pTemplate->rRun),
+                       MIN(p->nOut - 1, pTemplate->nOut)));
+      pTemplate->rRun = MIN(p->rRun, pTemplate->rRun);
+      pTemplate->nOut = MIN(p->nOut - 1, pTemplate->nOut);
+    }else if( whereLoopCheaperProperSubset(pTemplate, p) ){
+      /* Adjust pTemplate cost upward so that it is costlier than p since
+      ** pTemplate is a proper subset of p */
+      WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n",
+                       pTemplate->rRun, pTemplate->nOut,
+                       MAX(p->rRun, pTemplate->rRun),
+                       MAX(p->nOut + 1, pTemplate->nOut)));
+      pTemplate->rRun = MAX(p->rRun, pTemplate->rRun);
+      pTemplate->nOut = MAX(p->nOut + 1, pTemplate->nOut);
+    }
+  }
+}
+
+/*
+** Search the list of WhereLoops in *ppPrev looking for one that can be
+** replaced by pTemplate.
+**
+** Return NULL if pTemplate does not belong on the WhereLoop list.
+** In other words if pTemplate ought to be dropped from further consideration.
+**
+** If pX is a WhereLoop that pTemplate can replace, then return the
+** link that points to pX.
+**
+** If pTemplate cannot replace any existing element of the list but needs
+** to be added to the list as a new entry, then return a pointer to the
+** tail of the list.
+*/
+static WhereLoop **whereLoopFindLesser(
+  WhereLoop **ppPrev,
+  const WhereLoop *pTemplate
+){
+  WhereLoop *p;
+  for(p=(*ppPrev); p; ppPrev=&p->pNextLoop, p=*ppPrev){
+    if( p->iTab!=pTemplate->iTab || p->iSortIdx!=pTemplate->iSortIdx ){
+      /* If either the iTab or iSortIdx values for two WhereLoop are different
+      ** then those WhereLoops need to be considered separately.  Neither is
+      ** a candidate to replace the other. */
+      continue;
+    }
+    /* In the current implementation, the rSetup value is either zero
+    ** or the cost of building an automatic index (NlogN) and the NlogN
+    ** is the same for compatible WhereLoops. */
+    assert( p->rSetup==0 || pTemplate->rSetup==0
+                 || p->rSetup==pTemplate->rSetup );
+
+    /* whereLoopAddBtree() always generates and inserts the automatic index
+    ** case first.  Hence compatible candidate WhereLoops never have a larger
+    ** rSetup. Call this SETUP-INVARIANT */
+    assert( p->rSetup>=pTemplate->rSetup );
+
+    /* Any loop using an application-defined index (or PRIMARY KEY or
+    ** UNIQUE constraint) with one or more == constraints is better
+    ** than an automatic index. Unless it is a skip-scan. */
+    if( (p->wsFlags & WHERE_AUTO_INDEX)!=0
+     && (pTemplate->nSkip)==0
+     && (pTemplate->wsFlags & WHERE_INDEXED)!=0
+     && (pTemplate->wsFlags & WHERE_COLUMN_EQ)!=0
+     && (p->prereq & pTemplate->prereq)==pTemplate->prereq
+    ){
+      break;
+    }
+
+    /* If existing WhereLoop p is better than pTemplate, pTemplate can be
+    ** discarded.  WhereLoop p is better if:
+    **   (1)  p has no more dependencies than pTemplate, and
+    **   (2)  p has an equal or lower cost than pTemplate
+    */
+    if( (p->prereq & pTemplate->prereq)==p->prereq    /* (1)  */
+     && p->rSetup<=pTemplate->rSetup                  /* (2a) */
+     && p->rRun<=pTemplate->rRun                      /* (2b) */
+     && p->nOut<=pTemplate->nOut                      /* (2c) */
+    ){
+      return 0;  /* Discard pTemplate */
+    }
+
+    /* If pTemplate is always better than p, then cause p to be overwritten
+    ** with pTemplate.  pTemplate is better than p if:
+    **   (1)  pTemplate has no more dependencies than p, and
+    **   (2)  pTemplate has an equal or lower cost than p.
+    */
+    if( (p->prereq & pTemplate->prereq)==pTemplate->prereq   /* (1)  */
+     && p->rRun>=pTemplate->rRun                             /* (2a) */
+     && p->nOut>=pTemplate->nOut                             /* (2b) */
+    ){
+      assert( p->rSetup>=pTemplate->rSetup ); /* SETUP-INVARIANT above */
+      break;   /* Cause p to be overwritten by pTemplate */
+    }
+  }
+  return ppPrev;
+}
+
+/*
+** Insert or replace a WhereLoop entry using the template supplied.
+**
+** An existing WhereLoop entry might be overwritten if the new template
+** is better and has fewer dependencies.  Or the template will be ignored
+** and no insert will occur if an existing WhereLoop is faster and has
+** fewer dependencies than the template.  Otherwise a new WhereLoop is
+** added based on the template.
+**
+** If pBuilder->pOrSet is not NULL then we care about only the
+** prerequisites and rRun and nOut costs of the N best loops.  That
+** information is gathered in the pBuilder->pOrSet object.  This special
+** processing mode is used only for OR clause processing.
+**
+** When accumulating multiple loops (when pBuilder->pOrSet is NULL) we
+** still might overwrite similar loops with the new template if the
+** new template is better.  Loops may be overwritten if the following
+** conditions are met:
+**
+**    (1)  They have the same iTab.
+**    (2)  They have the same iSortIdx.
+**    (3)  The template has same or fewer dependencies than the current loop
+**    (4)  The template has the same or lower cost than the current loop
+*/
+static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
+  WhereLoop **ppPrev, *p;
+  WhereInfo *pWInfo = pBuilder->pWInfo;
+  sqlite3 *db = pWInfo->pParse->db;
+  int rc;
+
+  /* Stop the search once we hit the query planner search limit */
+  if( pBuilder->iPlanLimit==0 ){
+    WHERETRACE(0xffffffff,("=== query planner search limit reached ===\n"));
+    if( pBuilder->pOrSet ) pBuilder->pOrSet->n = 0;
+    return SQLITE_DONE;
+  }
+  pBuilder->iPlanLimit--;
+
+  whereLoopAdjustCost(pWInfo->pLoops, pTemplate);
+
+  /* If pBuilder->pOrSet is defined, then only keep track of the costs
+  ** and prereqs.
+  */
+  if( pBuilder->pOrSet!=0 ){
+    if( pTemplate->nLTerm ){
+#if WHERETRACE_ENABLED
+      u16 n = pBuilder->pOrSet->n;
+      int x =
+#endif
+      whereOrInsert(pBuilder->pOrSet, pTemplate->prereq, pTemplate->rRun,
+                                    pTemplate->nOut);
+#if WHERETRACE_ENABLED /* 0x8 */
+      if( sqlite3WhereTrace & 0x8 ){
+        sqlite3DebugPrintf(x?"   or-%d:  ":"   or-X:  ", n);
+        sqlite3WhereLoopPrint(pTemplate, pBuilder->pWC);
+      }
+#endif
+    }
+    return SQLITE_OK;
+  }
+
+  /* Look for an existing WhereLoop to replace with pTemplate
+  */
+  ppPrev = whereLoopFindLesser(&pWInfo->pLoops, pTemplate);
+
+  if( ppPrev==0 ){
+    /* There already exists a WhereLoop on the list that is better
+    ** than pTemplate, so just ignore pTemplate */
+#if WHERETRACE_ENABLED /* 0x8 */
+    if( sqlite3WhereTrace & 0x8 ){
+      sqlite3DebugPrintf("   skip: ");
+      sqlite3WhereLoopPrint(pTemplate, pBuilder->pWC);
+    }
+#endif
+    return SQLITE_OK;
+  }else{
+    p = *ppPrev;
+  }
+
+  /* If we reach this point it means that either p[] should be overwritten
+  ** with pTemplate[] if p[] exists, or if p==NULL then allocate a new
+  ** WhereLoop and insert it.
+  */
+#if WHERETRACE_ENABLED /* 0x8 */
+  if( sqlite3WhereTrace & 0x8 ){
+    if( p!=0 ){
+      sqlite3DebugPrintf("replace: ");
+      sqlite3WhereLoopPrint(p, pBuilder->pWC);
+      sqlite3DebugPrintf("   with: ");
+    }else{
+      sqlite3DebugPrintf("    add: ");
+    }
+    sqlite3WhereLoopPrint(pTemplate, pBuilder->pWC);
+  }
+#endif
+  if( p==0 ){
+    /* Allocate a new WhereLoop to add to the end of the list */
+    *ppPrev = p = sqlite3DbMallocRawNN(db, sizeof(WhereLoop));
+    if( p==0 ) return SQLITE_NOMEM_BKPT;
+    whereLoopInit(p);
+    p->pNextLoop = 0;
+  }else{
+    /* We will be overwriting WhereLoop p[].  But before we do, first
+    ** go through the rest of the list and delete any other entries besides
+    ** p[] that are also supplanted by pTemplate */
+    WhereLoop **ppTail = &p->pNextLoop;
+    WhereLoop *pToDel;
+    while( *ppTail ){
+      ppTail = whereLoopFindLesser(ppTail, pTemplate);
+      if( ppTail==0 ) break;
+      pToDel = *ppTail;
+      if( pToDel==0 ) break;
+      *ppTail = pToDel->pNextLoop;
+#if WHERETRACE_ENABLED /* 0x8 */
+      if( sqlite3WhereTrace & 0x8 ){
+        sqlite3DebugPrintf(" delete: ");
+        sqlite3WhereLoopPrint(pToDel, pBuilder->pWC);
+      }
+#endif
+      whereLoopDelete(db, pToDel);
+    }
+  }
+  rc = whereLoopXfer(db, p, pTemplate);
+  if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
+    Index *pIndex = p->u.btree.pIndex;
+    if( pIndex && pIndex->idxType==SQLITE_IDXTYPE_IPK ){
+      p->u.btree.pIndex = 0;
+    }
+  }
+  return rc;
+}
+
+/*
+** Adjust the WhereLoop.nOut value downward to account for terms of the
+** WHERE clause that reference the loop but which are not used by an
+** index.
+*
+** For every WHERE clause term that is not used by the index
+** and which has a truth probability assigned by one of the likelihood(),
+** likely(), or unlikely() SQL functions, reduce the estimated number
+** of output rows by the probability specified.
+**
+** TUNING:  For every WHERE clause term that is not used by the index
+** and which does not have an assigned truth probability, heuristics
+** described below are used to try to estimate the truth probability.
+** TODO --> Perhaps this is something that could be improved by better
+** table statistics.
+**
+** Heuristic 1:  Estimate the truth probability as 93.75%.  The 93.75%
+** value corresponds to -1 in LogEst notation, so this means decrement
+** the WhereLoop.nOut field for every such WHERE clause term.
+**
+** Heuristic 2:  If there exists one or more WHERE clause terms of the
+** form "x==EXPR" and EXPR is not a constant 0 or 1, then make sure the
+** final output row estimate is no greater than 1/4 of the total number
+** of rows in the table.  In other words, assume that x==EXPR will filter
+** out at least 3 out of 4 rows.  If EXPR is -1 or 0 or 1, then maybe the
+** "x" column is boolean or else -1 or 0 or 1 is a common default value
+** on the "x" column and so in that case only cap the output row estimate
+** at 1/2 instead of 1/4.
+*/
+static void whereLoopOutputAdjust(
+  WhereClause *pWC,      /* The WHERE clause */
+  WhereLoop *pLoop,      /* The loop to adjust downward */
+  LogEst nRow            /* Number of rows in the entire table */
+){
+  WhereTerm *pTerm, *pX;
+  Bitmask notAllowed = ~(pLoop->prereq|pLoop->maskSelf);
+  int i, j;
+  LogEst iReduce = 0;    /* pLoop->nOut should not exceed nRow-iReduce */
+
+  assert( (pLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
+  for(i=pWC->nBase, pTerm=pWC->a; i>0; i--, pTerm++){
+    assert( pTerm!=0 );
+    if( (pTerm->prereqAll & notAllowed)!=0 ) continue;
+    if( (pTerm->prereqAll & pLoop->maskSelf)==0 ) continue;
+    if( (pTerm->wtFlags & TERM_VIRTUAL)!=0 ) continue;
+    for(j=pLoop->nLTerm-1; j>=0; j--){
+      pX = pLoop->aLTerm[j];
+      if( pX==0 ) continue;
+      if( pX==pTerm ) break;
+      if( pX->iParent>=0 && (&pWC->a[pX->iParent])==pTerm ) break;
+    }
+    if( j<0 ){
+      sqlite3ProgressCheck(pWC->pWInfo->pParse);
+      if( pLoop->maskSelf==pTerm->prereqAll ){
+        /* If there are extra terms in the WHERE clause not used by an index
+        ** that depend only on the table being scanned, and that will tend to
+        ** cause many rows to be omitted, then mark that table as
+        ** "self-culling".
+        **
+        ** 2022-03-24:  Self-culling only applies if either the extra terms
+        ** are straight comparison operators that are non-true with NULL
+        ** operand, or if the loop is not an OUTER JOIN.
+        */
+        if( (pTerm->eOperator & 0x3f)!=0
+         || (pWC->pWInfo->pTabList->a[pLoop->iTab].fg.jointype
+                  & (JT_LEFT|JT_LTORJ))==0
+        ){
+          pLoop->wsFlags |= WHERE_SELFCULL;
+        }
+      }
+      if( pTerm->truthProb<=0 ){
+        /* If a truth probability is specified using the likelihood() hints,
+        ** then use the probability provided by the application. */
+        pLoop->nOut += pTerm->truthProb;
+      }else{
+        /* In the absence of explicit truth probabilities, use heuristics to
+        ** guess a reasonable truth probability. */
+        pLoop->nOut--;
+        if( (pTerm->eOperator&(WO_EQ|WO_IS))!=0
+         && (pTerm->wtFlags & TERM_HIGHTRUTH)==0  /* tag-20200224-1 */
+        ){
+          Expr *pRight = pTerm->pExpr->pRight;
+          int k = 0;
+          testcase( pTerm->pExpr->op==TK_IS );
+          if( sqlite3ExprIsInteger(pRight, &k, 0) && k>=(-1) && k<=1 ){
+            k = 10;
+          }else{
+            k = 20;
+          }
+          if( iReduce<k ){
+            pTerm->wtFlags |= TERM_HEURTRUTH;
+            iReduce = k;
+          }
+        }
+      }
+    }
+  }
+  if( pLoop->nOut > nRow-iReduce ){
+    pLoop->nOut = nRow - iReduce;
+  }
+}
+
+/*
+** Term pTerm is a vector range comparison operation. The first comparison
+** in the vector can be optimized using column nEq of the index. This
+** function returns the total number of vector elements that can be used
+** as part of the range comparison.
+**
+** For example, if the query is:
+**
+**   WHERE a = ? AND (b, c, d) > (?, ?, ?)
+**
+** and the index:
+**
+**   CREATE INDEX ... ON (a, b, c, d, e)
+**
+** then this function would be invoked with nEq=1. The value returned in
+** this case is 3.
+*/
+static int whereRangeVectorLen(
+  Parse *pParse,       /* Parsing context */
+  int iCur,            /* Cursor open on pIdx */
+  Index *pIdx,         /* The index to be used for a inequality constraint */
+  int nEq,             /* Number of prior equality constraints on same index */
+  WhereTerm *pTerm     /* The vector inequality constraint */
+){
+  int nCmp = sqlite3ExprVectorSize(pTerm->pExpr->pLeft);
+  int i;
+
+  nCmp = MIN(nCmp, (pIdx->nColumn - nEq));
+  for(i=1; i<nCmp; i++){
+    /* Test if comparison i of pTerm is compatible with column (i+nEq)
+    ** of the index. If not, exit the loop.  */
+    char aff;                     /* Comparison affinity */
+    char idxaff = 0;              /* Indexed columns affinity */
+    CollSeq *pColl;               /* Comparison collation sequence */
+    Expr *pLhs, *pRhs;
+
+    assert( ExprUseXList(pTerm->pExpr->pLeft) );
+    pLhs = pTerm->pExpr->pLeft->x.pList->a[i].pExpr;
+    pRhs = pTerm->pExpr->pRight;
+    if( ExprUseXSelect(pRhs) ){
+      pRhs = pRhs->x.pSelect->pEList->a[i].pExpr;
+    }else{
+      pRhs = pRhs->x.pList->a[i].pExpr;
+    }
+
+    /* Check that the LHS of the comparison is a column reference to
+    ** the right column of the right source table. And that the sort
+    ** order of the index column is the same as the sort order of the
+    ** leftmost index column.  */
+    if( pLhs->op!=TK_COLUMN
+     || pLhs->iTable!=iCur
+     || pLhs->iColumn!=pIdx->aiColumn[i+nEq]
+     || pIdx->aSortOrder[i+nEq]!=pIdx->aSortOrder[nEq]
+    ){
+      break;
+    }
+
+    testcase( pLhs->iColumn==XN_ROWID );
+    aff = sqlite3CompareAffinity(pRhs, sqlite3ExprAffinity(pLhs));
+    idxaff = sqlite3TableColumnAffinity(pIdx->pTable, pLhs->iColumn);
+    if( aff!=idxaff ) break;
+
+    pColl = sqlite3BinaryCompareCollSeq(pParse, pLhs, pRhs);
+    if( pColl==0 ) break;
+    if( sqlite3StrICmp(pColl->zName, pIdx->azColl[i+nEq]) ) break;
+  }
+  return i;
+}
+
+/*
+** Adjust the cost C by the costMult factor T.  This only occurs if
+** compiled with -DSQLITE_ENABLE_COSTMULT
+*/
+#ifdef SQLITE_ENABLE_COSTMULT
+# define ApplyCostMultiplier(C,T)  C += T
+#else
+# define ApplyCostMultiplier(C,T)
+#endif
+
+/*
+** We have so far matched pBuilder->pNew->u.btree.nEq terms of the
+** index pIndex. Try to match one more.
+**
+** When this function is called, pBuilder->pNew->nOut contains the
+** number of rows expected to be visited by filtering using the nEq
+** terms only. If it is modified, this value is restored before this
+** function returns.
+**
+** If pProbe->idxType==SQLITE_IDXTYPE_IPK, that means pIndex is
+** a fake index used for the INTEGER PRIMARY KEY.
+*/
+static int whereLoopAddBtreeIndex(
+  WhereLoopBuilder *pBuilder,     /* The WhereLoop factory */
+  SrcItem *pSrc,                  /* FROM clause term being analyzed */
+  Index *pProbe,                  /* An index on pSrc */
+  LogEst nInMul                   /* log(Number of iterations due to IN) */
+){
+  WhereInfo *pWInfo = pBuilder->pWInfo;  /* WHERE analyze context */
+  Parse *pParse = pWInfo->pParse;        /* Parsing context */
+  sqlite3 *db = pParse->db;       /* Database connection malloc context */
+  WhereLoop *pNew;                /* Template WhereLoop under construction */
+  WhereTerm *pTerm;               /* A WhereTerm under consideration */
+  int opMask;                     /* Valid operators for constraints */
+  WhereScan scan;                 /* Iterator for WHERE terms */
+  Bitmask saved_prereq;           /* Original value of pNew->prereq */
+  u16 saved_nLTerm;               /* Original value of pNew->nLTerm */
+  u16 saved_nEq;                  /* Original value of pNew->u.btree.nEq */
+  u16 saved_nBtm;                 /* Original value of pNew->u.btree.nBtm */
+  u16 saved_nTop;                 /* Original value of pNew->u.btree.nTop */
+  u16 saved_nSkip;                /* Original value of pNew->nSkip */
+  u32 saved_wsFlags;              /* Original value of pNew->wsFlags */
+  LogEst saved_nOut;              /* Original value of pNew->nOut */
+  int rc = SQLITE_OK;             /* Return code */
+  LogEst rSize;                   /* Number of rows in the table */
+  LogEst rLogSize;                /* Logarithm of table size */
+  WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */
+
+  pNew = pBuilder->pNew;
+  assert( db->mallocFailed==0 || pParse->nErr>0 );
+  if( pParse->nErr ){
+    return pParse->rc;
+  }
+  WHERETRACE(0x800, ("BEGIN %s.addBtreeIdx(%s), nEq=%d, nSkip=%d, rRun=%d\n",
+                     pProbe->pTable->zName,pProbe->zName,
+                     pNew->u.btree.nEq, pNew->nSkip, pNew->rRun));
+
+  assert( (pNew->wsFlags & WHERE_VIRTUALTABLE)==0 );
+  assert( (pNew->wsFlags & WHERE_TOP_LIMIT)==0 );
+  if( pNew->wsFlags & WHERE_BTM_LIMIT ){
+    opMask = WO_LT|WO_LE;
+  }else{
+    assert( pNew->u.btree.nBtm==0 );
+    opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE|WO_ISNULL|WO_IS;
+  }
+  if( pProbe->bUnordered || pProbe->bLowQual ){
+    if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE);
+    if( pProbe->bLowQual && pSrc->fg.isIndexedBy==0 ){
+      opMask &= ~(WO_EQ|WO_IN|WO_IS);
+    }
+  }
+
+  assert( pNew->u.btree.nEq<pProbe->nColumn );
+  assert( pNew->u.btree.nEq<pProbe->nKeyCol
+       || pProbe->idxType!=SQLITE_IDXTYPE_PRIMARYKEY );
+
+  saved_nEq = pNew->u.btree.nEq;
+  saved_nBtm = pNew->u.btree.nBtm;
+  saved_nTop = pNew->u.btree.nTop;
+  saved_nSkip = pNew->nSkip;
+  saved_nLTerm = pNew->nLTerm;
+  saved_wsFlags = pNew->wsFlags;
+  saved_prereq = pNew->prereq;
+  saved_nOut = pNew->nOut;
+  pTerm = whereScanInit(&scan, pBuilder->pWC, pSrc->iCursor, saved_nEq,
+                        opMask, pProbe);
+  pNew->rSetup = 0;
+  rSize = pProbe->aiRowLogEst[0];
+  rLogSize = estLog(rSize);
+  for(; rc==SQLITE_OK && pTerm!=0; pTerm = whereScanNext(&scan)){
+    u16 eOp = pTerm->eOperator;   /* Shorthand for pTerm->eOperator */
+    LogEst rCostIdx;
+    LogEst nOutUnadjusted;        /* nOut before IN() and WHERE adjustments */
+    int nIn = 0;
+#ifdef SQLITE_ENABLE_STAT4
+    int nRecValid = pBuilder->nRecValid;
+#endif
+    if( (eOp==WO_ISNULL || (pTerm->wtFlags&TERM_VNULL)!=0)
+     && indexColumnNotNull(pProbe, saved_nEq)
+    ){
+      continue; /* ignore IS [NOT] NULL constraints on NOT NULL columns */
+    }
+    if( pTerm->prereqRight & pNew->maskSelf ) continue;
+
+    /* Do not allow the upper bound of a LIKE optimization range constraint
+    ** to mix with a lower range bound from some other source */
+    if( pTerm->wtFlags & TERM_LIKEOPT && pTerm->eOperator==WO_LT ) continue;
+
+    if( (pSrc->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0
+     && !constraintCompatibleWithOuterJoin(pTerm,pSrc)
+    ){
+      continue;
+    }
+    if( IsUniqueIndex(pProbe) && saved_nEq==pProbe->nKeyCol-1 ){
+      pBuilder->bldFlags1 |= SQLITE_BLDF1_UNIQUE;
+    }else{
+      pBuilder->bldFlags1 |= SQLITE_BLDF1_INDEXED;
+    }
+    pNew->wsFlags = saved_wsFlags;
+    pNew->u.btree.nEq = saved_nEq;
+    pNew->u.btree.nBtm = saved_nBtm;
+    pNew->u.btree.nTop = saved_nTop;
+    pNew->nLTerm = saved_nLTerm;
+    if( pNew->nLTerm>=pNew->nLSlot
+     && whereLoopResize(db, pNew, pNew->nLTerm+1)
+    ){
+       break; /* OOM while trying to enlarge the pNew->aLTerm array */
+    }
+    pNew->aLTerm[pNew->nLTerm++] = pTerm;
+    pNew->prereq = (saved_prereq | pTerm->prereqRight) & ~pNew->maskSelf;
+
+    assert( nInMul==0
+        || (pNew->wsFlags & WHERE_COLUMN_NULL)!=0
+        || (pNew->wsFlags & WHERE_COLUMN_IN)!=0
+        || (pNew->wsFlags & WHERE_SKIPSCAN)!=0
+    );
+
+    if( eOp & WO_IN ){
+      Expr *pExpr = pTerm->pExpr;
+      if( ExprUseXSelect(pExpr) ){
+        /* "x IN (SELECT ...)":  TUNING: the SELECT returns 25 rows */
+        int i;
+        nIn = 46;  assert( 46==sqlite3LogEst(25) );
+
+        /* The expression may actually be of the form (x, y) IN (SELECT...).
+        ** In this case there is a separate term for each of (x) and (y).
+        ** However, the nIn multiplier should only be applied once, not once
+        ** for each such term. The following loop checks that pTerm is the
+        ** first such term in use, and sets nIn back to 0 if it is not. */
+        for(i=0; i<pNew->nLTerm-1; i++){
+          if( pNew->aLTerm[i] && pNew->aLTerm[i]->pExpr==pExpr ) nIn = 0;
+        }
+      }else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
+        /* "x IN (value, value, ...)" */
+        nIn = sqlite3LogEst(pExpr->x.pList->nExpr);
+      }
+      if( pProbe->hasStat1 && rLogSize>=10 ){
+        LogEst M, logK, x;
+        /* Let:
+        **   N = the total number of rows in the table
+        **   K = the number of entries on the RHS of the IN operator
+        **   M = the number of rows in the table that match terms to the
+        **       to the left in the same index.  If the IN operator is on
+        **       the left-most index column, M==N.
+        **
+        ** Given the definitions above, it is better to omit the IN operator
+        ** from the index lookup and instead do a scan of the M elements,
+        ** testing each scanned row against the IN operator separately, if:
+        **
+        **        M*log(K) < K*log(N)
+        **
+        ** Our estimates for M, K, and N might be inaccurate, so we build in
+        ** a safety margin of 2 (LogEst: 10) that favors using the IN operator
+        ** with the index, as using an index has better worst-case behavior.
+        ** If we do not have real sqlite_stat1 data, always prefer to use
+        ** the index.  Do not bother with this optimization on very small
+        ** tables (less than 2 rows) as it is pointless in that case.
+        */
+        M = pProbe->aiRowLogEst[saved_nEq];
+        logK = estLog(nIn);
+        /* TUNING      v-----  10 to bias toward indexed IN */
+        x = M + logK + 10 - (nIn + rLogSize);
+        if( x>=0 ){
+          WHERETRACE(0x40,
+            ("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d) "
+             "prefers indexed lookup\n",
+             saved_nEq, M, logK, nIn, rLogSize, x));
+        }else if( nInMul<2 && OptimizationEnabled(db, SQLITE_SeekScan) ){
+          WHERETRACE(0x40,
+            ("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d"
+             " nInMul=%d) prefers skip-scan\n",
+             saved_nEq, M, logK, nIn, rLogSize, x, nInMul));
+          pNew->wsFlags |= WHERE_IN_SEEKSCAN;
+        }else{
+          WHERETRACE(0x40,
+            ("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d"
+             " nInMul=%d) prefers normal scan\n",
+             saved_nEq, M, logK, nIn, rLogSize, x, nInMul));
+          continue;
+        }
+      }
+      pNew->wsFlags |= WHERE_COLUMN_IN;
+    }else if( eOp & (WO_EQ|WO_IS) ){
+      int iCol = pProbe->aiColumn[saved_nEq];
+      pNew->wsFlags |= WHERE_COLUMN_EQ;
+      assert( saved_nEq==pNew->u.btree.nEq );
+      if( iCol==XN_ROWID
+       || (iCol>=0 && nInMul==0 && saved_nEq==pProbe->nKeyCol-1)
+      ){
+        if( iCol==XN_ROWID || pProbe->uniqNotNull
+         || (pProbe->nKeyCol==1 && pProbe->onError && (eOp & WO_EQ))
+        ){
+          pNew->wsFlags |= WHERE_ONEROW;
+        }else{
+          pNew->wsFlags |= WHERE_UNQ_WANTED;
+        }
+      }
+      if( scan.iEquiv>1 ) pNew->wsFlags |= WHERE_TRANSCONS;
+    }else if( eOp & WO_ISNULL ){
+      pNew->wsFlags |= WHERE_COLUMN_NULL;
+    }else{
+      int nVecLen = whereRangeVectorLen(
+          pParse, pSrc->iCursor, pProbe, saved_nEq, pTerm
+      );
+      if( eOp & (WO_GT|WO_GE) ){
+        testcase( eOp & WO_GT );
+        testcase( eOp & WO_GE );
+        pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_BTM_LIMIT;
+        pNew->u.btree.nBtm = nVecLen;
+        pBtm = pTerm;
+        pTop = 0;
+        if( pTerm->wtFlags & TERM_LIKEOPT ){
+          /* Range constraints that come from the LIKE optimization are
+          ** always used in pairs. */
+          pTop = &pTerm[1];
+          assert( (pTop-(pTerm->pWC->a))<pTerm->pWC->nTerm );
+          assert( pTop->wtFlags & TERM_LIKEOPT );
+          assert( pTop->eOperator==WO_LT );
+          if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */
+          pNew->aLTerm[pNew->nLTerm++] = pTop;
+          pNew->wsFlags |= WHERE_TOP_LIMIT;
+          pNew->u.btree.nTop = 1;
+        }
+      }else{
+        assert( eOp & (WO_LT|WO_LE) );
+        testcase( eOp & WO_LT );
+        testcase( eOp & WO_LE );
+        pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_TOP_LIMIT;
+        pNew->u.btree.nTop = nVecLen;
+        pTop = pTerm;
+        pBtm = (pNew->wsFlags & WHERE_BTM_LIMIT)!=0 ?
+                       pNew->aLTerm[pNew->nLTerm-2] : 0;
+      }
+    }
+
+    /* At this point pNew->nOut is set to the number of rows expected to
+    ** be visited by the index scan before considering term pTerm, or the
+    ** values of nIn and nInMul. In other words, assuming that all
+    ** "x IN(...)" terms are replaced with "x = ?". This block updates
+    ** the value of pNew->nOut to account for pTerm (but not nIn/nInMul).  */
+    assert( pNew->nOut==saved_nOut );
+    if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
+      /* Adjust nOut using stat4 data. Or, if there is no stat4
+      ** data, using some other estimate.  */
+      whereRangeScanEst(pParse, pBuilder, pBtm, pTop, pNew);
+    }else{
+      int nEq = ++pNew->u.btree.nEq;
+      assert( eOp & (WO_ISNULL|WO_EQ|WO_IN|WO_IS) );
+
+      assert( pNew->nOut==saved_nOut );
+      if( pTerm->truthProb<=0 && pProbe->aiColumn[saved_nEq]>=0 ){
+        assert( (eOp & WO_IN) || nIn==0 );
+        testcase( eOp & WO_IN );
+        pNew->nOut += pTerm->truthProb;
+        pNew->nOut -= nIn;
+      }else{
+#ifdef SQLITE_ENABLE_STAT4
+        tRowcnt nOut = 0;
+        if( nInMul==0
+         && pProbe->nSample
+         && ALWAYS(pNew->u.btree.nEq<=pProbe->nSampleCol)
+         && ((eOp & WO_IN)==0 || ExprUseXList(pTerm->pExpr))
+         && OptimizationEnabled(db, SQLITE_Stat4)
+        ){
+          Expr *pExpr = pTerm->pExpr;
+          if( (eOp & (WO_EQ|WO_ISNULL|WO_IS))!=0 ){
+            testcase( eOp & WO_EQ );
+            testcase( eOp & WO_IS );
+            testcase( eOp & WO_ISNULL );
+            rc = whereEqualScanEst(pParse, pBuilder, pExpr->pRight, &nOut);
+          }else{
+            rc = whereInScanEst(pParse, pBuilder, pExpr->x.pList, &nOut);
+          }
+          if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+          if( rc!=SQLITE_OK ) break;          /* Jump out of the pTerm loop */
+          if( nOut ){
+            pNew->nOut = sqlite3LogEst(nOut);
+            if( nEq==1
+             /* TUNING: Mark terms as "low selectivity" if they seem likely
+             ** to be true for half or more of the rows in the table.
+             ** See tag-202002240-1 */
+             && pNew->nOut+10 > pProbe->aiRowLogEst[0]
+            ){
+#if WHERETRACE_ENABLED /* 0x01 */
+              if( sqlite3WhereTrace & 0x20 ){
+                sqlite3DebugPrintf(
+                   "STAT4 determines term has low selectivity:\n");
+                sqlite3WhereTermPrint(pTerm, 999);
+              }
+#endif
+              pTerm->wtFlags |= TERM_HIGHTRUTH;
+              if( pTerm->wtFlags & TERM_HEURTRUTH ){
+                /* If the term has previously been used with an assumption of
+                ** higher selectivity, then set the flag to rerun the
+                ** loop computations. */
+                pBuilder->bldFlags2 |= SQLITE_BLDF2_2NDPASS;
+              }
+            }
+            if( pNew->nOut>saved_nOut ) pNew->nOut = saved_nOut;
+            pNew->nOut -= nIn;
+          }
+        }
+        if( nOut==0 )
+#endif
+        {
+          pNew->nOut += (pProbe->aiRowLogEst[nEq] - pProbe->aiRowLogEst[nEq-1]);
+          if( eOp & WO_ISNULL ){
+            /* TUNING: If there is no likelihood() value, assume that a
+            ** "col IS NULL" expression matches twice as many rows
+            ** as (col=?). */
+            pNew->nOut += 10;
+          }
+        }
+      }
+    }
+
+    /* Set rCostIdx to the estimated cost of visiting selected rows in the
+    ** index.  The estimate is the sum of two values:
+    **   1.  The cost of doing one search-by-key to find the first matching
+    **       entry
+    **   2.  Stepping forward in the index pNew->nOut times to find all
+    **       additional matching entries.
+    */
+    assert( pSrc->pSTab->szTabRow>0 );
+    if( pProbe->idxType==SQLITE_IDXTYPE_IPK ){
+      /* The pProbe->szIdxRow is low for an IPK table since the interior
+      ** pages are small.  Thus szIdxRow gives a good estimate of seek cost.
+      ** But the leaf pages are full-size, so pProbe->szIdxRow would badly
+      ** under-estimate the scanning cost. */
+      rCostIdx = pNew->nOut + 16;
+    }else{
+      rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pSTab->szTabRow;
+    }
+    rCostIdx = sqlite3LogEstAdd(rLogSize, rCostIdx);
+
+    /* Estimate the cost of running the loop.  If all data is coming
+    ** from the index, then this is just the cost of doing the index
+    ** lookup and scan.  But if some data is coming out of the main table,
+    ** we also have to add in the cost of doing pNew->nOut searches to
+    ** locate the row in the main table that corresponds to the index entry.
+    */
+    pNew->rRun = rCostIdx;
+    if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK|WHERE_EXPRIDX))==0 ){
+      pNew->rRun = sqlite3LogEstAdd(pNew->rRun, pNew->nOut + 16);
+    }
+    ApplyCostMultiplier(pNew->rRun, pProbe->pTable->costMult);
+
+    nOutUnadjusted = pNew->nOut;
+    pNew->rRun += nInMul + nIn;
+    pNew->nOut += nInMul + nIn;
+    whereLoopOutputAdjust(pBuilder->pWC, pNew, rSize);
+    rc = whereLoopInsert(pBuilder, pNew);
+
+    if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
+      pNew->nOut = saved_nOut;
+    }else{
+      pNew->nOut = nOutUnadjusted;
+    }
+
+    if( (pNew->wsFlags & WHERE_TOP_LIMIT)==0
+     && pNew->u.btree.nEq<pProbe->nColumn
+     && (pNew->u.btree.nEq<pProbe->nKeyCol ||
+          (pProbe->idxType!=SQLITE_IDXTYPE_PRIMARYKEY && !pProbe->bIdxRowid))
+    ){
+      if( pNew->u.btree.nEq>3 ){
+        sqlite3ProgressCheck(pParse);
+      }
+      whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nInMul+nIn);
+    }
+    pNew->nOut = saved_nOut;
+#ifdef SQLITE_ENABLE_STAT4
+    pBuilder->nRecValid = nRecValid;
+#endif
+  }
+  pNew->prereq = saved_prereq;
+  pNew->u.btree.nEq = saved_nEq;
+  pNew->u.btree.nBtm = saved_nBtm;
+  pNew->u.btree.nTop = saved_nTop;
+  pNew->nSkip = saved_nSkip;
+  pNew->wsFlags = saved_wsFlags;
+  pNew->nOut = saved_nOut;
+  pNew->nLTerm = saved_nLTerm;
+
+  /* Consider using a skip-scan if there are no WHERE clause constraints
+  ** available for the left-most terms of the index, and if the average
+  ** number of repeats in the left-most terms is at least 18.
+  **
+  ** The magic number 18 is selected on the basis that scanning 17 rows
+  ** is almost always quicker than an index seek (even though if the index
+  ** contains fewer than 2^17 rows we assume otherwise in other parts of
+  ** the code). And, even if it is not, it should not be too much slower.
+  ** On the other hand, the extra seeks could end up being significantly
+  ** more expensive.  */
+  assert( 42==sqlite3LogEst(18) );
+  if( saved_nEq==saved_nSkip
+   && saved_nEq+1<pProbe->nKeyCol
+   && saved_nEq==pNew->nLTerm
+   && pProbe->noSkipScan==0
+   && pProbe->hasStat1!=0
+   && OptimizationEnabled(db, SQLITE_SkipScan)
+   && pProbe->aiRowLogEst[saved_nEq+1]>=42  /* TUNING: Minimum for skip-scan */
+   && (rc = whereLoopResize(db, pNew, pNew->nLTerm+1))==SQLITE_OK
+  ){
+    LogEst nIter;
+    pNew->u.btree.nEq++;
+    pNew->nSkip++;
+    pNew->aLTerm[pNew->nLTerm++] = 0;
+    pNew->wsFlags |= WHERE_SKIPSCAN;
+    nIter = pProbe->aiRowLogEst[saved_nEq] - pProbe->aiRowLogEst[saved_nEq+1];
+    pNew->nOut -= nIter;
+    /* TUNING:  Because uncertainties in the estimates for skip-scan queries,
+    ** add a 1.375 fudge factor to make skip-scan slightly less likely. */
+    nIter += 5;
+    whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nIter + nInMul);
+    pNew->nOut = saved_nOut;
+    pNew->u.btree.nEq = saved_nEq;
+    pNew->nSkip = saved_nSkip;
+    pNew->wsFlags = saved_wsFlags;
+  }
+
+  WHERETRACE(0x800, ("END %s.addBtreeIdx(%s), nEq=%d, rc=%d\n",
+                      pProbe->pTable->zName, pProbe->zName, saved_nEq, rc));
+  return rc;
+}
+
+/*
+** Return True if it is possible that pIndex might be useful in
+** implementing the ORDER BY clause in pBuilder.
+**
+** Return False if pBuilder does not contain an ORDER BY clause or
+** if there is no way for pIndex to be useful in implementing that
+** ORDER BY clause.
+*/
+static int indexMightHelpWithOrderBy(
+  WhereLoopBuilder *pBuilder,
+  Index *pIndex,
+  int iCursor
+){
+  ExprList *pOB;
+  ExprList *aColExpr;
+  int ii, jj;
+
+  if( pIndex->bUnordered ) return 0;
+  if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
+  for(ii=0; ii<pOB->nExpr; ii++){
+    Expr *pExpr = sqlite3ExprSkipCollateAndLikely(pOB->a[ii].pExpr);
+    if( NEVER(pExpr==0) ) continue;
+    if( (pExpr->op==TK_COLUMN || pExpr->op==TK_AGG_COLUMN)
+     && pExpr->iTable==iCursor
+    ){
+      if( pExpr->iColumn<0 ) return 1;
+      for(jj=0; jj<pIndex->nKeyCol; jj++){
+        if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
+      }
+    }else if( (aColExpr = pIndex->aColExpr)!=0 ){
+      for(jj=0; jj<pIndex->nKeyCol; jj++){
+        if( pIndex->aiColumn[jj]!=XN_EXPR ) continue;
+        if( sqlite3ExprCompareSkip(pExpr,aColExpr->a[jj].pExpr,iCursor)==0 ){
+          return 1;
+        }
+      }
+    }
+  }
+  return 0;
+}
+
+/* Check to see if a partial index with pPartIndexWhere can be used
+** in the current query.  Return true if it can be and false if not.
+*/
+static int whereUsablePartialIndex(
+  int iTab,             /* The table for which we want an index */
+  u8 jointype,          /* The JT_* flags on the join */
+  WhereClause *pWC,     /* The WHERE clause of the query */
+  Expr *pWhere          /* The WHERE clause from the partial index */
+){
+  int i;
+  WhereTerm *pTerm;
+  Parse *pParse;
+
+  if( jointype & JT_LTORJ ) return 0;
+  pParse = pWC->pWInfo->pParse;
+  while( pWhere->op==TK_AND ){
+    if( !whereUsablePartialIndex(iTab,jointype,pWC,pWhere->pLeft) ) return 0;
+    pWhere = pWhere->pRight;
+  }
+  for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
+    Expr *pExpr;
+    pExpr = pTerm->pExpr;
+    if( (!ExprHasProperty(pExpr, EP_OuterON) || pExpr->w.iJoin==iTab)
+     && ((jointype & JT_OUTER)==0 || ExprHasProperty(pExpr, EP_OuterON))
+     && sqlite3ExprImpliesExpr(pParse, pExpr, pWhere, iTab)
+     && (pTerm->wtFlags & TERM_VNULL)==0
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** pIdx is an index containing expressions.  Check it see if any of the
+** expressions in the index match the pExpr expression.
+*/
+static int exprIsCoveredByIndex(
+  const Expr *pExpr,
+  const Index *pIdx,
+  int iTabCur
+){
+  int i;
+  for(i=0; i<pIdx->nColumn; i++){
+    if( pIdx->aiColumn[i]==XN_EXPR
+     && sqlite3ExprCompare(0, pExpr, pIdx->aColExpr->a[i].pExpr, iTabCur)==0
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Structure passed to the whereIsCoveringIndex Walker callback.
+*/
+typedef struct CoveringIndexCheck CoveringIndexCheck;
+struct CoveringIndexCheck {
+  Index *pIdx;       /* The index */
+  int iTabCur;       /* Cursor number for the corresponding table */
+  u8 bExpr;          /* Uses an indexed expression */
+  u8 bUnidx;         /* Uses an unindexed column not within an indexed expr */
+};
+
+/*
+** Information passed in is pWalk->u.pCovIdxCk.  Call it pCk.
+**
+** If the Expr node references the table with cursor pCk->iTabCur, then
+** make sure that column is covered by the index pCk->pIdx.  We know that
+** all columns less than 63 (really BMS-1) are covered, so we don't need
+** to check them.  But we do need to check any column at 63 or greater.
+**
+** If the index does not cover the column, then set pWalk->eCode to
+** non-zero and return WRC_Abort to stop the search.
+**
+** If this node does not disprove that the index can be a covering index,
+** then just return WRC_Continue, to continue the search.
+**
+** If pCk->pIdx contains indexed expressions and one of those expressions
+** matches pExpr, then prune the search.
+*/
+static int whereIsCoveringIndexWalkCallback(Walker *pWalk, Expr *pExpr){
+  int i;                    /* Loop counter */
+  const Index *pIdx;        /* The index of interest */
+  const i16 *aiColumn;      /* Columns contained in the index */
+  u16 nColumn;              /* Number of columns in the index */
+  CoveringIndexCheck *pCk;  /* Info about this search */
+
+  pCk = pWalk->u.pCovIdxCk;
+  pIdx = pCk->pIdx;
+  if( (pExpr->op==TK_COLUMN || pExpr->op==TK_AGG_COLUMN) ){
+    /* if( pExpr->iColumn<(BMS-1) && pIdx->bHasExpr==0 ) return WRC_Continue;*/
+    if( pExpr->iTable!=pCk->iTabCur ) return WRC_Continue;
+    pIdx = pWalk->u.pCovIdxCk->pIdx;
+    aiColumn = pIdx->aiColumn;
+    nColumn = pIdx->nColumn;
+    for(i=0; i<nColumn; i++){
+      if( aiColumn[i]==pExpr->iColumn ) return WRC_Continue;
+    }
+    pCk->bUnidx = 1;
+    return WRC_Abort;
+  }else if( pIdx->bHasExpr
+         && exprIsCoveredByIndex(pExpr, pIdx, pWalk->u.pCovIdxCk->iTabCur) ){
+    pCk->bExpr = 1;
+    return WRC_Prune;
+  }
+  return WRC_Continue;
+}
+
+
+/*
+** pIdx is an index that covers all of the low-number columns used by
+** pWInfo->pSelect (columns from 0 through 62) or an index that has
+** expressions terms.  Hence, we cannot determine whether or not it is
+** a covering index by using the colUsed bitmasks.  We have to do a search
+** to see if the index is covering.  This routine does that search.
+**
+** The return value is one of these:
+**
+**      0                The index is definitely not a covering index
+**
+**      WHERE_IDX_ONLY   The index is definitely a covering index
+**
+**      WHERE_EXPRIDX    The index is likely a covering index, but it is
+**                       difficult to determine precisely because of the
+**                       expressions that are indexed.  Score it as a
+**                       covering index, but still keep the main table open
+**                       just in case we need it.
+**
+** This routine is an optimization.  It is always safe to return zero.
+** But returning one of the other two values when zero should have been
+** returned can lead to incorrect bytecode and assertion faults.
+*/
+static SQLITE_NOINLINE u32 whereIsCoveringIndex(
+  WhereInfo *pWInfo,     /* The WHERE clause context */
+  Index *pIdx,           /* Index that is being tested */
+  int iTabCur            /* Cursor for the table being indexed */
+){
+  int i, rc;
+  struct CoveringIndexCheck ck;
+  Walker w;
+  if( pWInfo->pSelect==0 ){
+    /* We don't have access to the full query, so we cannot check to see
+    ** if pIdx is covering.  Assume it is not. */
+    return 0;
+  }
+  if( pIdx->bHasExpr==0 ){
+    for(i=0; i<pIdx->nColumn; i++){
+      if( pIdx->aiColumn[i]>=BMS-1 ) break;
+    }
+    if( i>=pIdx->nColumn ){
+      /* pIdx does not index any columns greater than 62, but we know from
+      ** colMask that columns greater than 62 are used, so this is not a
+      ** covering index */
+      return 0;
+    }
+  }
+  ck.pIdx = pIdx;
+  ck.iTabCur = iTabCur;
+  ck.bExpr = 0;
+  ck.bUnidx = 0;
+  memset(&w, 0, sizeof(w));
+  w.xExprCallback = whereIsCoveringIndexWalkCallback;
+  w.xSelectCallback = sqlite3SelectWalkNoop;
+  w.u.pCovIdxCk = &ck;
+  sqlite3WalkSelect(&w, pWInfo->pSelect);
+  if( ck.bUnidx ){
+    rc = 0;
+  }else if( ck.bExpr ){
+    rc = WHERE_EXPRIDX;
+  }else{
+    rc = WHERE_IDX_ONLY;
+  }
+  return rc;
+}
+
+/*
+** This is an sqlite3ParserAddCleanup() callback that is invoked to
+** free the Parse->pIdxEpr list when the Parse object is destroyed.
+*/
+static void whereIndexedExprCleanup(sqlite3 *db, void *pObject){
+  IndexedExpr **pp = (IndexedExpr**)pObject;
+  while( *pp!=0 ){
+    IndexedExpr *p = *pp;
+    *pp = p->pIENext;
+    sqlite3ExprDelete(db, p->pExpr);
+    sqlite3DbFreeNN(db, p);
+  }
+}
+
+/*
+** This function is called for a partial index - one with a WHERE clause - in
+** two scenarios. In both cases, it determines whether or not the WHERE
+** clause on the index implies that a column of the table may be safely
+** replaced by a constant expression. For example, in the following
+** SELECT:
+**
+**   CREATE INDEX i1 ON t1(b, c) WHERE a=<expr>;
+**   SELECT a, b, c FROM t1 WHERE a=<expr> AND b=?;
+**
+** The "a" in the select-list may be replaced by <expr>, iff:
+**
+**    (a) <expr> is a constant expression, and
+**    (b) The (a=<expr>) comparison uses the BINARY collation sequence, and
+**    (c) Column "a" has an affinity other than NONE or BLOB.
+**
+** If argument pItem is NULL, then pMask must not be NULL. In this case this
+** function is being called as part of determining whether or not pIdx
+** is a covering index. This function clears any bits in (*pMask)
+** corresponding to columns that may be replaced by constants as described
+** above.
+**
+** Otherwise, if pItem is not NULL, then this function is being called
+** as part of coding a loop that uses index pIdx. In this case, add entries
+** to the Parse.pIdxPartExpr list for each column that can be replaced
+** by a constant.
+*/
+static void wherePartIdxExpr(
+  Parse *pParse,                  /* Parse context */
+  Index *pIdx,                    /* Partial index being processed */
+  Expr *pPart,                    /* WHERE clause being processed */
+  Bitmask *pMask,                 /* Mask to clear bits in */
+  int iIdxCur,                    /* Cursor number for index */
+  SrcItem *pItem                  /* The FROM clause entry for the table */
+){
+  assert( pItem==0 || (pItem->fg.jointype & JT_RIGHT)==0 );
+  assert( (pItem==0 || pMask==0) && (pMask!=0 || pItem!=0) );
+
+  if( pPart->op==TK_AND ){
+    wherePartIdxExpr(pParse, pIdx, pPart->pRight, pMask, iIdxCur, pItem);
+    pPart = pPart->pLeft;
+  }
+
+  if( (pPart->op==TK_EQ || pPart->op==TK_IS) ){
+    Expr *pLeft = pPart->pLeft;
+    Expr *pRight = pPart->pRight;
+    u8 aff;
+
+    if( pLeft->op!=TK_COLUMN ) return;
+    if( !sqlite3ExprIsConstant(0, pRight) ) return;
+    if( !sqlite3IsBinary(sqlite3ExprCompareCollSeq(pParse, pPart)) ) return;
+    if( pLeft->iColumn<0 ) return;
+    aff = pIdx->pTable->aCol[pLeft->iColumn].affinity;
+    if( aff>=SQLITE_AFF_TEXT ){
+      if( pItem ){
+        sqlite3 *db = pParse->db;
+        IndexedExpr *p = (IndexedExpr*)sqlite3DbMallocRaw(db, sizeof(*p));
+        if( p ){
+          int bNullRow = (pItem->fg.jointype&(JT_LEFT|JT_LTORJ))!=0;
+          p->pExpr = sqlite3ExprDup(db, pRight, 0);
+          p->iDataCur = pItem->iCursor;
+          p->iIdxCur = iIdxCur;
+          p->iIdxCol = pLeft->iColumn;
+          p->bMaybeNullRow = bNullRow;
+          p->pIENext = pParse->pIdxPartExpr;
+          p->aff = aff;
+          pParse->pIdxPartExpr = p;
+          if( p->pIENext==0 ){
+            void *pArg = (void*)&pParse->pIdxPartExpr;
+            sqlite3ParserAddCleanup(pParse, whereIndexedExprCleanup, pArg);
+          }
+        }
+      }else if( pLeft->iColumn<(BMS-1) ){
+        *pMask &= ~((Bitmask)1 << pLeft->iColumn);
+      }
+    }
+  }
+}
+
+
+/*
+** Add all WhereLoop objects for a single table of the join where the table
+** is identified by pBuilder->pNew->iTab.  That table is guaranteed to be
+** a b-tree table, not a virtual table.
+**
+** The costs (WhereLoop.rRun) of the b-tree loops added by this function
+** are calculated as follows:
+**
+** For a full scan, assuming the table (or index) contains nRow rows:
+**
+**     cost = nRow * 3.0                    // full-table scan
+**     cost = nRow * K                      // scan of covering index
+**     cost = nRow * (K+3.0)                // scan of non-covering index
+**
+** where K is a value between 1.1 and 3.0 set based on the relative
+** estimated average size of the index and table records.
+**
+** For an index scan, where nVisit is the number of index rows visited
+** by the scan, and nSeek is the number of seek operations required on
+** the index b-tree:
+**
+**     cost = nSeek * (log(nRow) + K * nVisit)          // covering index
+**     cost = nSeek * (log(nRow) + (K+3.0) * nVisit)    // non-covering index
+**
+** Normally, nSeek is 1. nSeek values greater than 1 come about if the
+** WHERE clause includes "x IN (....)" terms used in place of "x=?". Or when
+** implicit "x IN (SELECT x FROM tbl)" terms are added for skip-scans.
+**
+** The estimated values (nRow, nVisit, nSeek) often contain a large amount
+** of uncertainty.  For this reason, scoring is designed to pick plans that
+** "do the least harm" if the estimates are inaccurate.  For example, a
+** log(nRow) factor is omitted from a non-covering index scan in order to
+** bias the scoring in favor of using an index, since the worst-case
+** performance of using an index is far better than the worst-case performance
+** of a full table scan.
+*/
+static int whereLoopAddBtree(
+  WhereLoopBuilder *pBuilder, /* WHERE clause information */
+  Bitmask mPrereq             /* Extra prerequisites for using this table */
+){
+  WhereInfo *pWInfo;          /* WHERE analysis context */
+  Index *pProbe;              /* An index we are evaluating */
+  Index sPk;                  /* A fake index object for the primary key */
+  LogEst aiRowEstPk[2];       /* The aiRowLogEst[] value for the sPk index */
+  i16 aiColumnPk = -1;        /* The aColumn[] value for the sPk index */
+  SrcList *pTabList;          /* The FROM clause */
+  SrcItem *pSrc;              /* The FROM clause btree term to add */
+  WhereLoop *pNew;            /* Template WhereLoop object */
+  int rc = SQLITE_OK;         /* Return code */
+  int iSortIdx = 1;           /* Index number */
+  int b;                      /* A boolean value */
+  LogEst rSize;               /* number of rows in the table */
+  WhereClause *pWC;           /* The parsed WHERE clause */
+  Table *pTab;                /* Table being queried */
+
+  pNew = pBuilder->pNew;
+  pWInfo = pBuilder->pWInfo;
+  pTabList = pWInfo->pTabList;
+  pSrc = pTabList->a + pNew->iTab;
+  pTab = pSrc->pSTab;
+  pWC = pBuilder->pWC;
+  assert( !IsVirtual(pSrc->pSTab) );
+
+  if( pSrc->fg.isIndexedBy ){
+    assert( pSrc->fg.isCte==0 );
+    /* An INDEXED BY clause specifies a particular index to use */
+    pProbe = pSrc->u2.pIBIndex;
+  }else if( !HasRowid(pTab) ){
+    pProbe = pTab->pIndex;
+  }else{
+    /* There is no INDEXED BY clause.  Create a fake Index object in local
+    ** variable sPk to represent the rowid primary key index.  Make this
+    ** fake index the first in a chain of Index objects with all of the real
+    ** indices to follow */
+    Index *pFirst;                  /* First of real indices on the table */
+    memset(&sPk, 0, sizeof(Index));
+    sPk.nKeyCol = 1;
+    sPk.nColumn = 1;
+    sPk.aiColumn = &aiColumnPk;
+    sPk.aiRowLogEst = aiRowEstPk;
+    sPk.onError = OE_Replace;
+    sPk.pTable = pTab;
+    sPk.szIdxRow = 3;  /* TUNING: Interior rows of IPK table are very small */
+    sPk.idxType = SQLITE_IDXTYPE_IPK;
+    aiRowEstPk[0] = pTab->nRowLogEst;
+    aiRowEstPk[1] = 0;
+    pFirst = pSrc->pSTab->pIndex;
+    if( pSrc->fg.notIndexed==0 ){
+      /* The real indices of the table are only considered if the
+      ** NOT INDEXED qualifier is omitted from the FROM clause */
+      sPk.pNext = pFirst;
+    }
+    pProbe = &sPk;
+  }
+  rSize = pTab->nRowLogEst;
+
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+  /* Automatic indexes */
+  if( !pBuilder->pOrSet      /* Not part of an OR optimization */
+   && (pWInfo->wctrlFlags & (WHERE_RIGHT_JOIN|WHERE_OR_SUBCLAUSE))==0
+   && (pWInfo->pParse->db->flags & SQLITE_AutoIndex)!=0
+   && !pSrc->fg.isIndexedBy  /* Has no INDEXED BY clause */
+   && !pSrc->fg.notIndexed   /* Has no NOT INDEXED clause */
+   && !pSrc->fg.isCorrelated /* Not a correlated subquery */
+   && !pSrc->fg.isRecursive  /* Not a recursive common table expression. */
+   && (pSrc->fg.jointype & JT_RIGHT)==0 /* Not the right tab of a RIGHT JOIN */
+  ){
+    /* Generate auto-index WhereLoops */
+    LogEst rLogSize;         /* Logarithm of the number of rows in the table */
+    WhereTerm *pTerm;
+    WhereTerm *pWCEnd = pWC->a + pWC->nTerm;
+    rLogSize = estLog(rSize);
+    for(pTerm=pWC->a; rc==SQLITE_OK && pTerm<pWCEnd; pTerm++){
+      if( pTerm->prereqRight & pNew->maskSelf ) continue;
+      if( termCanDriveIndex(pTerm, pSrc, 0) ){
+        pNew->u.btree.nEq = 1;
+        pNew->nSkip = 0;
+        pNew->u.btree.pIndex = 0;
+        pNew->nLTerm = 1;
+        pNew->aLTerm[0] = pTerm;
+        /* TUNING: One-time cost for computing the automatic index is
+        ** estimated to be X*N*log2(N) where N is the number of rows in
+        ** the table being indexed and where X is 7 (LogEst=28) for normal
+        ** tables or 0.5 (LogEst=-10) for views and subqueries.  The value
+        ** of X is smaller for views and subqueries so that the query planner
+        ** will be more aggressive about generating automatic indexes for
+        ** those objects, since there is no opportunity to add schema
+        ** indexes on subqueries and views. */
+        pNew->rSetup = rLogSize + rSize;
+        if( !IsView(pTab) && (pTab->tabFlags & TF_Ephemeral)==0 ){
+          pNew->rSetup += 28;
+        }else{
+          pNew->rSetup -= 25;  /* Greatly reduced setup cost for auto indexes
+                               ** on ephemeral materializations of views */
+        }
+        ApplyCostMultiplier(pNew->rSetup, pTab->costMult);
+        if( pNew->rSetup<0 ) pNew->rSetup = 0;
+        /* TUNING: Each index lookup yields 20 rows in the table.  This
+        ** is more than the usual guess of 10 rows, since we have no way
+        ** of knowing how selective the index will ultimately be.  It would
+        ** not be unreasonable to make this value much larger. */
+        pNew->nOut = 43;  assert( 43==sqlite3LogEst(20) );
+        pNew->rRun = sqlite3LogEstAdd(rLogSize,pNew->nOut);
+        pNew->wsFlags = WHERE_AUTO_INDEX;
+        pNew->prereq = mPrereq | pTerm->prereqRight;
+        rc = whereLoopInsert(pBuilder, pNew);
+      }
+    }
+  }
+#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */
+
+  /* Loop over all indices. If there was an INDEXED BY clause, then only
+  ** consider index pProbe.  */
+  for(; rc==SQLITE_OK && pProbe;
+      pProbe=(pSrc->fg.isIndexedBy ? 0 : pProbe->pNext), iSortIdx++
+  ){
+    if( pProbe->pPartIdxWhere!=0
+     && !whereUsablePartialIndex(pSrc->iCursor, pSrc->fg.jointype, pWC,
+                                 pProbe->pPartIdxWhere)
+    ){
+      testcase( pNew->iTab!=pSrc->iCursor );  /* See ticket [98d973b8f5] */
+      continue;  /* Partial index inappropriate for this query */
+    }
+    if( pProbe->bNoQuery ) continue;
+    rSize = pProbe->aiRowLogEst[0];
+    pNew->u.btree.nEq = 0;
+    pNew->u.btree.nBtm = 0;
+    pNew->u.btree.nTop = 0;
+    pNew->nSkip = 0;
+    pNew->nLTerm = 0;
+    pNew->iSortIdx = 0;
+    pNew->rSetup = 0;
+    pNew->prereq = mPrereq;
+    pNew->nOut = rSize;
+    pNew->u.btree.pIndex = pProbe;
+    pNew->u.btree.pOrderBy = 0;
+    b = indexMightHelpWithOrderBy(pBuilder, pProbe, pSrc->iCursor);
+
+    /* The ONEPASS_DESIRED flags never occurs together with ORDER BY */
+    assert( (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || b==0 );
+    if( pProbe->idxType==SQLITE_IDXTYPE_IPK ){
+      /* Integer primary key index */
+      pNew->wsFlags = WHERE_IPK;
+
+      /* Full table scan */
+      pNew->iSortIdx = b ? iSortIdx : 0;
+      /* TUNING: Cost of full table scan is 3.0*N.  The 3.0 factor is an
+      ** extra cost designed to discourage the use of full table scans,
+      ** since index lookups have better worst-case performance if our
+      ** stat guesses are wrong.  Reduce the 3.0 penalty slightly
+      ** (to 2.75) if we have valid STAT4 information for the table.
+      ** At 2.75, a full table scan is preferred over using an index on
+      ** a column with just two distinct values where each value has about
+      ** an equal number of appearances.  Without STAT4 data, we still want
+      ** to use an index in that case, since the constraint might be for
+      ** the scarcer of the two values, and in that case an index lookup is
+      ** better.
+      */
+#ifdef SQLITE_ENABLE_STAT4
+      pNew->rRun = rSize + 16 - 2*((pTab->tabFlags & TF_HasStat4)!=0);
+#else
+      pNew->rRun = rSize + 16;
+#endif
+      ApplyCostMultiplier(pNew->rRun, pTab->costMult);
+      whereLoopOutputAdjust(pWC, pNew, rSize);
+      if( pSrc->fg.isSubquery ){
+        if( pSrc->fg.viaCoroutine ) pNew->wsFlags |= WHERE_COROUTINE;
+        pNew->u.btree.pOrderBy = pSrc->u4.pSubq->pSelect->pOrderBy;
+      }
+      rc = whereLoopInsert(pBuilder, pNew);
+      pNew->nOut = rSize;
+      if( rc ) break;
+    }else{
+      Bitmask m;
+      if( pProbe->isCovering ){
+        m = 0;
+        pNew->wsFlags = WHERE_IDX_ONLY | WHERE_INDEXED;
+      }else{
+        m = pSrc->colUsed & pProbe->colNotIdxed;
+        if( pProbe->pPartIdxWhere ){
+          wherePartIdxExpr(
+              pWInfo->pParse, pProbe, pProbe->pPartIdxWhere, &m, 0, 0
+          );
+        }
+        pNew->wsFlags = WHERE_INDEXED;
+        if( m==TOPBIT || (pProbe->bHasExpr && !pProbe->bHasVCol && m!=0) ){
+          u32 isCov = whereIsCoveringIndex(pWInfo, pProbe, pSrc->iCursor);
+          if( isCov==0 ){
+            WHERETRACE(0x200,
+               ("-> %s is not a covering index"
+                " according to whereIsCoveringIndex()\n", pProbe->zName));
+            assert( m!=0 );
+          }else{
+            m = 0;
+            pNew->wsFlags |= isCov;
+            if( isCov & WHERE_IDX_ONLY ){
+              WHERETRACE(0x200,
+                 ("-> %s is a covering expression index"
+                  " according to whereIsCoveringIndex()\n", pProbe->zName));
+            }else{
+              assert( isCov==WHERE_EXPRIDX );
+              WHERETRACE(0x200,
+                 ("-> %s might be a covering expression index"
+                  " according to whereIsCoveringIndex()\n", pProbe->zName));
+            }
+          }
+        }else if( m==0
+           && (HasRowid(pTab) || pWInfo->pSelect!=0 || sqlite3FaultSim(700))
+        ){
+          WHERETRACE(0x200,
+             ("-> %s a covering index according to bitmasks\n",
+             pProbe->zName, m==0 ? "is" : "is not"));
+          pNew->wsFlags = WHERE_IDX_ONLY | WHERE_INDEXED;
+        }
+      }
+
+      /* Full scan via index */
+      if( b
+       || !HasRowid(pTab)
+       || pProbe->pPartIdxWhere!=0
+       || pSrc->fg.isIndexedBy
+       || ( m==0
+         && pProbe->bUnordered==0
+         && (pProbe->szIdxRow<pTab->szTabRow)
+         && (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0
+         && sqlite3GlobalConfig.bUseCis
+         && OptimizationEnabled(pWInfo->pParse->db, SQLITE_CoverIdxScan)
+          )
+      ){
+        pNew->iSortIdx = b ? iSortIdx : 0;
+
+        /* The cost of visiting the index rows is N*K, where K is
+        ** between 1.1 and 3.0, depending on the relative sizes of the
+        ** index and table rows. */
+        pNew->rRun = rSize + 1 + (15*pProbe->szIdxRow)/pTab->szTabRow;
+        if( m!=0 ){
+          /* If this is a non-covering index scan, add in the cost of
+          ** doing table lookups.  The cost will be 3x the number of
+          ** lookups.  Take into account WHERE clause terms that can be
+          ** satisfied using just the index, and that do not require a
+          ** table lookup. */
+          LogEst nLookup = rSize + 16;  /* Base cost:  N*3 */
+          int ii;
+          int iCur = pSrc->iCursor;
+          WhereClause *pWC2 = &pWInfo->sWC;
+          for(ii=0; ii<pWC2->nTerm; ii++){
+            WhereTerm *pTerm = &pWC2->a[ii];
+            if( !sqlite3ExprCoveredByIndex(pTerm->pExpr, iCur, pProbe) ){
+              break;
+            }
+            /* pTerm can be evaluated using just the index.  So reduce
+            ** the expected number of table lookups accordingly */
+            if( pTerm->truthProb<=0 ){
+              nLookup += pTerm->truthProb;
+            }else{
+              nLookup--;
+              if( pTerm->eOperator & (WO_EQ|WO_IS) ) nLookup -= 19;
+            }
+          }
+
+          pNew->rRun = sqlite3LogEstAdd(pNew->rRun, nLookup);
+        }
+        ApplyCostMultiplier(pNew->rRun, pTab->costMult);
+        whereLoopOutputAdjust(pWC, pNew, rSize);
+        if( (pSrc->fg.jointype & JT_RIGHT)!=0 && pProbe->aColExpr ){
+          /* Do not do an SCAN of a index-on-expression in a RIGHT JOIN
+          ** because the cursor used to access the index might not be
+          ** positioned to the correct row during the right-join no-match
+          ** loop. */
+        }else{
+          rc = whereLoopInsert(pBuilder, pNew);
+        }
+        pNew->nOut = rSize;
+        if( rc ) break;
+      }
+    }
+
+    pBuilder->bldFlags1 = 0;
+    rc = whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, 0);
+    if( pBuilder->bldFlags1==SQLITE_BLDF1_INDEXED ){
+      /* If a non-unique index is used, or if a prefix of the key for
+      ** unique index is used (making the index functionally non-unique)
+      ** then the sqlite_stat1 data becomes important for scoring the
+      ** plan */
+      pTab->tabFlags |= TF_MaybeReanalyze;
+    }
+#ifdef SQLITE_ENABLE_STAT4
+    sqlite3Stat4ProbeFree(pBuilder->pRec);
+    pBuilder->nRecValid = 0;
+    pBuilder->pRec = 0;
+#endif
+  }
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+
+/*
+** Return true if pTerm is a virtual table LIMIT or OFFSET term.
+*/
+static int isLimitTerm(WhereTerm *pTerm){
+  assert( pTerm->eOperator==WO_AUX || pTerm->eMatchOp==0 );
+  return pTerm->eMatchOp>=SQLITE_INDEX_CONSTRAINT_LIMIT
+      && pTerm->eMatchOp<=SQLITE_INDEX_CONSTRAINT_OFFSET;
+}
+
+/*
+** Return true if the first nCons constraints in the pUsage array are
+** marked as in-use (have argvIndex>0). False otherwise.
+*/
+static int allConstraintsUsed(
+  struct sqlite3_index_constraint_usage *aUsage,
+  int nCons
+){
+  int ii;
+  for(ii=0; ii<nCons; ii++){
+    if( aUsage[ii].argvIndex<=0 ) return 0;
+  }
+  return 1;
+}
+
+/*
+** Argument pIdxInfo is already populated with all constraints that may
+** be used by the virtual table identified by pBuilder->pNew->iTab. This
+** function marks a subset of those constraints usable, invokes the
+** xBestIndex method and adds the returned plan to pBuilder.
+**
+** A constraint is marked usable if:
+**
+**   * Argument mUsable indicates that its prerequisites are available, and
+**
+**   * It is not one of the operators specified in the mExclude mask passed
+**     as the fourth argument (which in practice is either WO_IN or 0).
+**
+** Argument mPrereq is a mask of tables that must be scanned before the
+** virtual table in question. These are added to the plans prerequisites
+** before it is added to pBuilder.
+**
+** Output parameter *pbIn is set to true if the plan added to pBuilder
+** uses one or more WO_IN terms, or false otherwise.
+*/
+static int whereLoopAddVirtualOne(
+  WhereLoopBuilder *pBuilder,
+  Bitmask mPrereq,                /* Mask of tables that must be used. */
+  Bitmask mUsable,                /* Mask of usable tables */
+  u16 mExclude,                   /* Exclude terms using these operators */
+  sqlite3_index_info *pIdxInfo,   /* Populated object for xBestIndex */
+  u16 mNoOmit,                    /* Do not omit these constraints */
+  int *pbIn,                      /* OUT: True if plan uses an IN(...) op */
+  int *pbRetryLimit               /* OUT: Retry without LIMIT/OFFSET */
+){
+  WhereClause *pWC = pBuilder->pWC;
+  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  struct sqlite3_index_constraint *pIdxCons;
+  struct sqlite3_index_constraint_usage *pUsage = pIdxInfo->aConstraintUsage;
+  int i;
+  int mxTerm;
+  int rc = SQLITE_OK;
+  WhereLoop *pNew = pBuilder->pNew;
+  Parse *pParse = pBuilder->pWInfo->pParse;
+  SrcItem *pSrc = &pBuilder->pWInfo->pTabList->a[pNew->iTab];
+  int nConstraint = pIdxInfo->nConstraint;
+
+  assert( (mUsable & mPrereq)==mPrereq );
+  *pbIn = 0;
+  pNew->prereq = mPrereq;
+
+  /* Set the usable flag on the subset of constraints identified by
+  ** arguments mUsable and mExclude. */
+  pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
+  for(i=0; i<nConstraint; i++, pIdxCons++){
+    WhereTerm *pTerm = termFromWhereClause(pWC, pIdxCons->iTermOffset);
+    pIdxCons->usable = 0;
+    if( (pTerm->prereqRight & mUsable)==pTerm->prereqRight
+     && (pTerm->eOperator & mExclude)==0
+     && (pbRetryLimit || !isLimitTerm(pTerm))
+    ){
+      pIdxCons->usable = 1;
+    }
+  }
+
+  /* Initialize the output fields of the sqlite3_index_info structure */
+  memset(pUsage, 0, sizeof(pUsage[0])*nConstraint);
+  assert( pIdxInfo->needToFreeIdxStr==0 );
+  pIdxInfo->idxStr = 0;
+  pIdxInfo->idxNum = 0;
+  pIdxInfo->orderByConsumed = 0;
+  pIdxInfo->estimatedCost = SQLITE_BIG_DBL / (double)2;
+  pIdxInfo->estimatedRows = 25;
+  pIdxInfo->idxFlags = 0;
+  pHidden->mHandleIn = 0;
+
+  /* Invoke the virtual table xBestIndex() method */
+  rc = vtabBestIndex(pParse, pSrc->pSTab, pIdxInfo);
+  if( rc ){
+    if( rc==SQLITE_CONSTRAINT ){
+      /* If the xBestIndex method returns SQLITE_CONSTRAINT, that means
+      ** that the particular combination of parameters provided is unusable.
+      ** Make no entries in the loop table.
+      */
+      WHERETRACE(0xffffffff, ("  ^^^^--- non-viable plan rejected!\n"));
+      freeIdxStr(pIdxInfo);
+      return SQLITE_OK;
+    }
+    return rc;
+  }
+
+  mxTerm = -1;
+  assert( pNew->nLSlot>=nConstraint );
+  memset(pNew->aLTerm, 0, sizeof(pNew->aLTerm[0])*nConstraint );
+  memset(&pNew->u.vtab, 0, sizeof(pNew->u.vtab));
+  pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
+  for(i=0; i<nConstraint; i++, pIdxCons++){
+    int iTerm;
+    if( (iTerm = pUsage[i].argvIndex - 1)>=0 ){
+      WhereTerm *pTerm;
+      int j = pIdxCons->iTermOffset;
+      if( iTerm>=nConstraint
+       || j<0
+       || (pTerm = termFromWhereClause(pWC, j))==0
+       || pNew->aLTerm[iTerm]!=0
+       || pIdxCons->usable==0
+      ){
+        sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pSTab->zName);
+        freeIdxStr(pIdxInfo);
+        return SQLITE_ERROR;
+      }
+      testcase( iTerm==nConstraint-1 );
+      testcase( j==0 );
+      testcase( j==pWC->nTerm-1 );
+      pNew->prereq |= pTerm->prereqRight;
+      assert( iTerm<pNew->nLSlot );
+      pNew->aLTerm[iTerm] = pTerm;
+      if( iTerm>mxTerm ) mxTerm = iTerm;
+      testcase( iTerm==15 );
+      testcase( iTerm==16 );
+      if( pUsage[i].omit ){
+        if( i<16 && ((1<<i)&mNoOmit)==0 ){
+          testcase( i!=iTerm );
+          pNew->u.vtab.omitMask |= 1<<iTerm;
+        }else{
+          testcase( i!=iTerm );
+        }
+        if( pTerm->eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET ){
+          pNew->u.vtab.bOmitOffset = 1;
+        }
+      }
+      if( SMASKBIT32(i) & pHidden->mHandleIn ){
+        pNew->u.vtab.mHandleIn |= MASKBIT32(iTerm);
+      }else if( (pTerm->eOperator & WO_IN)!=0 ){
+        /* A virtual table that is constrained by an IN clause may not
+        ** consume the ORDER BY clause because (1) the order of IN terms
+        ** is not necessarily related to the order of output terms and
+        ** (2) Multiple outputs from a single IN value will not merge
+        ** together.  */
+        pIdxInfo->orderByConsumed = 0;
+        pIdxInfo->idxFlags &= ~SQLITE_INDEX_SCAN_UNIQUE;
+        *pbIn = 1; assert( (mExclude & WO_IN)==0 );
+      }
+
+      /* Unless pbRetryLimit is non-NULL, there should be no LIMIT/OFFSET
+      ** terms. And if there are any, they should follow all other terms. */
+      assert( pbRetryLimit || !isLimitTerm(pTerm) );
+      assert( !isLimitTerm(pTerm) || i>=nConstraint-2 );
+      assert( !isLimitTerm(pTerm) || i==nConstraint-1 || isLimitTerm(pTerm+1) );
+
+      if( isLimitTerm(pTerm) && (*pbIn || !allConstraintsUsed(pUsage, i)) ){
+        /* If there is an IN(...) term handled as an == (separate call to
+        ** xFilter for each value on the RHS of the IN) and a LIMIT or
+        ** OFFSET term handled as well, the plan is unusable. Similarly,
+        ** if there is a LIMIT/OFFSET and there are other unused terms,
+        ** the plan cannot be used. In these cases set variable *pbRetryLimit
+        ** to true to tell the caller to retry with LIMIT and OFFSET
+        ** disabled. */
+        freeIdxStr(pIdxInfo);
+        *pbRetryLimit = 1;
+        return SQLITE_OK;
+      }
+    }
+  }
+
+  pNew->nLTerm = mxTerm+1;
+  for(i=0; i<=mxTerm; i++){
+    if( pNew->aLTerm[i]==0 ){
+      /* The non-zero argvIdx values must be contiguous.  Raise an
+      ** error if they are not */
+      sqlite3ErrorMsg(pParse,"%s.xBestIndex malfunction",pSrc->pSTab->zName);
+      freeIdxStr(pIdxInfo);
+      return SQLITE_ERROR;
+    }
+  }
+  assert( pNew->nLTerm<=pNew->nLSlot );
+  pNew->u.vtab.idxNum = pIdxInfo->idxNum;
+  pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
+  pIdxInfo->needToFreeIdxStr = 0;
+  pNew->u.vtab.idxStr = pIdxInfo->idxStr;
+  pNew->u.vtab.isOrdered = (i8)(pIdxInfo->orderByConsumed ?
+      pIdxInfo->nOrderBy : 0);
+  pNew->u.vtab.bIdxNumHex = (pIdxInfo->idxFlags&SQLITE_INDEX_SCAN_HEX)!=0;
+  pNew->rSetup = 0;
+  pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost);
+  pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows);
+
+  /* Set the WHERE_ONEROW flag if the xBestIndex() method indicated
+  ** that the scan will visit at most one row. Clear it otherwise. */
+  if( pIdxInfo->idxFlags & SQLITE_INDEX_SCAN_UNIQUE ){
+    pNew->wsFlags |= WHERE_ONEROW;
+  }else{
+    pNew->wsFlags &= ~WHERE_ONEROW;
+  }
+  rc = whereLoopInsert(pBuilder, pNew);
+  if( pNew->u.vtab.needFree ){
+    sqlite3_free(pNew->u.vtab.idxStr);
+    pNew->u.vtab.needFree = 0;
+  }
+  WHERETRACE(0xffffffff, ("  bIn=%d prereqIn=%04llx prereqOut=%04llx\n",
+                      *pbIn, (sqlite3_uint64)mPrereq,
+                      (sqlite3_uint64)(pNew->prereq & ~mPrereq)));
+
+  return rc;
+}
+
+/*
+** Return the collating sequence for a constraint passed into xBestIndex.
+**
+** pIdxInfo must be an sqlite3_index_info structure passed into xBestIndex.
+** This routine depends on there being a HiddenIndexInfo structure immediately
+** following the sqlite3_index_info structure.
+**
+** Return a pointer to the collation name:
+**
+**    1. If there is an explicit COLLATE operator on the constraint, return it.
+**
+**    2. Else, if the column has an alternative collation, return that.
+**
+**    3. Otherwise, return "BINARY".
+*/
+SQLITE_API const char *sqlite3_vtab_collation(sqlite3_index_info *pIdxInfo, int iCons){
+  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  const char *zRet = 0;
+  if( iCons>=0 && iCons<pIdxInfo->nConstraint ){
+    CollSeq *pC = 0;
+    int iTerm = pIdxInfo->aConstraint[iCons].iTermOffset;
+    Expr *pX = termFromWhereClause(pHidden->pWC, iTerm)->pExpr;
+    if( pX->pLeft ){
+      pC = sqlite3ExprCompareCollSeq(pHidden->pParse, pX);
+    }
+    zRet = (pC ? pC->zName : sqlite3StrBINARY);
+  }
+  return zRet;
+}
+
+/*
+** Return true if constraint iCons is really an IN(...) constraint, or
+** false otherwise. If iCons is an IN(...) constraint, set (if bHandle!=0)
+** or clear (if bHandle==0) the flag to handle it using an iterator.
+*/
+SQLITE_API int sqlite3_vtab_in(sqlite3_index_info *pIdxInfo, int iCons, int bHandle){
+  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  u32 m = SMASKBIT32(iCons);
+  if( m & pHidden->mIn ){
+    if( bHandle==0 ){
+      pHidden->mHandleIn &= ~m;
+    }else if( bHandle>0 ){
+      pHidden->mHandleIn |= m;
+    }
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** This interface is callable from within the xBestIndex callback only.
+**
+** If possible, set (*ppVal) to point to an object containing the value
+** on the right-hand-side of constraint iCons.
+*/
+SQLITE_API int sqlite3_vtab_rhs_value(
+  sqlite3_index_info *pIdxInfo,   /* Copy of first argument to xBestIndex */
+  int iCons,                      /* Constraint for which RHS is wanted */
+  sqlite3_value **ppVal           /* Write value extracted here */
+){
+  HiddenIndexInfo *pH = (HiddenIndexInfo*)&pIdxInfo[1];
+  sqlite3_value *pVal = 0;
+  int rc = SQLITE_OK;
+  if( iCons<0 || iCons>=pIdxInfo->nConstraint ){
+    rc = SQLITE_MISUSE_BKPT; /* EV: R-30545-25046 */
+  }else{
+    if( pH->aRhs[iCons]==0 ){
+      WhereTerm *pTerm = termFromWhereClause(
+          pH->pWC, pIdxInfo->aConstraint[iCons].iTermOffset
+      );
+      rc = sqlite3ValueFromExpr(
+          pH->pParse->db, pTerm->pExpr->pRight, ENC(pH->pParse->db),
+          SQLITE_AFF_BLOB, &pH->aRhs[iCons]
+      );
+      testcase( rc!=SQLITE_OK );
+    }
+    pVal = pH->aRhs[iCons];
+  }
+  *ppVal = pVal;
+
+  if( rc==SQLITE_OK && pVal==0 ){  /* IMP: R-19933-32160 */
+    rc = SQLITE_NOTFOUND;          /* IMP: R-36424-56542 */
+  }
+
+  return rc;
+}
+
+/*
+** Return true if ORDER BY clause may be handled as DISTINCT.
+*/
+SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info *pIdxInfo){
+  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
+  assert( pHidden->eDistinct>=0 && pHidden->eDistinct<=3 );
+  return pHidden->eDistinct;
+}
+
+/*
+** Cause the prepared statement that is associated with a call to
+** xBestIndex to potentially use all schemas.  If the statement being
+** prepared is read-only, then just start read transactions on all
+** schemas.  But if this is a write operation, start writes on all
+** schemas.
+**
+** This is used by the (built-in) sqlite_dbpage virtual table.
+*/
+SQLITE_PRIVATE void sqlite3VtabUsesAllSchemas(Parse *pParse){
+  int nDb = pParse->db->nDb;
+  int i;
+  for(i=0; i<nDb; i++){
+    sqlite3CodeVerifySchema(pParse, i);
+  }
+  if( DbMaskNonZero(pParse->writeMask) ){
+    for(i=0; i<nDb; i++){
+      sqlite3BeginWriteOperation(pParse, 0, i);
+    }
+  }
+}
+
+/*
+** Add all WhereLoop objects for a table of the join identified by
+** pBuilder->pNew->iTab.  That table is guaranteed to be a virtual table.
+**
+** If there are no LEFT or CROSS JOIN joins in the query, both mPrereq and
+** mUnusable are set to 0. Otherwise, mPrereq is a mask of all FROM clause
+** entries that occur before the virtual table in the FROM clause and are
+** separated from it by at least one LEFT or CROSS JOIN. Similarly, the
+** mUnusable mask contains all FROM clause entries that occur after the
+** virtual table and are separated from it by at least one LEFT or
+** CROSS JOIN.
+**
+** For example, if the query were:
+**
+**   ... FROM t1, t2 LEFT JOIN t3, t4, vt CROSS JOIN t5, t6;
+**
+** then mPrereq corresponds to (t1, t2) and mUnusable to (t5, t6).
+**
+** All the tables in mPrereq must be scanned before the current virtual
+** table. So any terms for which all prerequisites are satisfied by
+** mPrereq may be specified as "usable" in all calls to xBestIndex.
+** Conversely, all tables in mUnusable must be scanned after the current
+** virtual table, so any terms for which the prerequisites overlap with
+** mUnusable should always be configured as "not-usable" for xBestIndex.
+*/
+static int whereLoopAddVirtual(
+  WhereLoopBuilder *pBuilder,  /* WHERE clause information */
+  Bitmask mPrereq,             /* Tables that must be scanned before this one */
+  Bitmask mUnusable            /* Tables that must be scanned after this one */
+){
+  int rc = SQLITE_OK;          /* Return code */
+  WhereInfo *pWInfo;           /* WHERE analysis context */
+  Parse *pParse;               /* The parsing context */
+  WhereClause *pWC;            /* The WHERE clause */
+  SrcItem *pSrc;               /* The FROM clause term to search */
+  sqlite3_index_info *p;       /* Object to pass to xBestIndex() */
+  int nConstraint;             /* Number of constraints in p */
+  int bIn;                     /* True if plan uses IN(...) operator */
+  WhereLoop *pNew;
+  Bitmask mBest;               /* Tables used by best possible plan */
+  u16 mNoOmit;
+  int bRetry = 0;              /* True to retry with LIMIT/OFFSET disabled */
+
+  assert( (mPrereq & mUnusable)==0 );
+  pWInfo = pBuilder->pWInfo;
+  pParse = pWInfo->pParse;
+  pWC = pBuilder->pWC;
+  pNew = pBuilder->pNew;
+  pSrc = &pWInfo->pTabList->a[pNew->iTab];
+  assert( IsVirtual(pSrc->pSTab) );
+  p = allocateIndexInfo(pWInfo, pWC, mUnusable, pSrc, &mNoOmit);
+  if( p==0 ) return SQLITE_NOMEM_BKPT;
+  pNew->rSetup = 0;
+  pNew->wsFlags = WHERE_VIRTUALTABLE;
+  pNew->nLTerm = 0;
+  pNew->u.vtab.needFree = 0;
+  nConstraint = p->nConstraint;
+  if( whereLoopResize(pParse->db, pNew, nConstraint) ){
+    freeIndexInfo(pParse->db, p);
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  /* First call xBestIndex() with all constraints usable. */
+  WHERETRACE(0x800, ("BEGIN %s.addVirtual()\n", pSrc->pSTab->zName));
+  WHERETRACE(0x800, ("  VirtualOne: all usable\n"));
+  rc = whereLoopAddVirtualOne(
+      pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn, &bRetry
+  );
+  if( bRetry ){
+    assert( rc==SQLITE_OK );
+    rc = whereLoopAddVirtualOne(
+        pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn, 0
+    );
+  }
+
+  /* If the call to xBestIndex() with all terms enabled produced a plan
+  ** that does not require any source tables (IOW: a plan with mBest==0)
+  ** and does not use an IN(...) operator, then there is no point in making
+  ** any further calls to xBestIndex() since they will all return the same
+  ** result (if the xBestIndex() implementation is sane). */
+  if( rc==SQLITE_OK && ((mBest = (pNew->prereq & ~mPrereq))!=0 || bIn) ){
+    int seenZero = 0;             /* True if a plan with no prereqs seen */
+    int seenZeroNoIN = 0;         /* Plan with no prereqs and no IN(...) seen */
+    Bitmask mPrev = 0;
+    Bitmask mBestNoIn = 0;
+
+    /* If the plan produced by the earlier call uses an IN(...) term, call
+    ** xBestIndex again, this time with IN(...) terms disabled. */
+    if( bIn ){
+      WHERETRACE(0x800, ("  VirtualOne: all usable w/o IN\n"));
+      rc = whereLoopAddVirtualOne(
+          pBuilder, mPrereq, ALLBITS, WO_IN, p, mNoOmit, &bIn, 0);
+      assert( bIn==0 );
+      mBestNoIn = pNew->prereq & ~mPrereq;
+      if( mBestNoIn==0 ){
+        seenZero = 1;
+        seenZeroNoIN = 1;
+      }
+    }
+
+    /* Call xBestIndex once for each distinct value of (prereqRight & ~mPrereq)
+    ** in the set of terms that apply to the current virtual table.  */
+    while( rc==SQLITE_OK ){
+      int i;
+      Bitmask mNext = ALLBITS;
+      assert( mNext>0 );
+      for(i=0; i<nConstraint; i++){
+        int iTerm = p->aConstraint[i].iTermOffset;
+        Bitmask mThis = termFromWhereClause(pWC, iTerm)->prereqRight & ~mPrereq;
+        if( mThis>mPrev && mThis<mNext ) mNext = mThis;
+      }
+      mPrev = mNext;
+      if( mNext==ALLBITS ) break;
+      if( mNext==mBest || mNext==mBestNoIn ) continue;
+      WHERETRACE(0x800, ("  VirtualOne: mPrev=%04llx mNext=%04llx\n",
+                       (sqlite3_uint64)mPrev, (sqlite3_uint64)mNext));
+      rc = whereLoopAddVirtualOne(
+          pBuilder, mPrereq, mNext|mPrereq, 0, p, mNoOmit, &bIn, 0);
+      if( pNew->prereq==mPrereq ){
+        seenZero = 1;
+        if( bIn==0 ) seenZeroNoIN = 1;
+      }
+    }
+
+    /* If the calls to xBestIndex() in the above loop did not find a plan
+    ** that requires no source tables at all (i.e. one guaranteed to be
+    ** usable), make a call here with all source tables disabled */
+    if( rc==SQLITE_OK && seenZero==0 ){
+      WHERETRACE(0x800, ("  VirtualOne: all disabled\n"));
+      rc = whereLoopAddVirtualOne(
+          pBuilder, mPrereq, mPrereq, 0, p, mNoOmit, &bIn, 0);
+      if( bIn==0 ) seenZeroNoIN = 1;
+    }
+
+    /* If the calls to xBestIndex() have so far failed to find a plan
+    ** that requires no source tables at all and does not use an IN(...)
+    ** operator, make a final call to obtain one here.  */
+    if( rc==SQLITE_OK && seenZeroNoIN==0 ){
+      WHERETRACE(0x800, ("  VirtualOne: all disabled and w/o IN\n"));
+      rc = whereLoopAddVirtualOne(
+          pBuilder, mPrereq, mPrereq, WO_IN, p, mNoOmit, &bIn, 0);
+    }
+  }
+
+  freeIndexInfo(pParse->db, p);
+  WHERETRACE(0x800, ("END %s.addVirtual(), rc=%d\n", pSrc->pSTab->zName, rc));
+  return rc;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/*
+** Add WhereLoop entries to handle OR terms.  This works for either
+** btrees or virtual tables.
+*/
+static int whereLoopAddOr(
+  WhereLoopBuilder *pBuilder,
+  Bitmask mPrereq,
+  Bitmask mUnusable
+){
+  WhereInfo *pWInfo = pBuilder->pWInfo;
+  WhereClause *pWC;
+  WhereLoop *pNew;
+  WhereTerm *pTerm, *pWCEnd;
+  int rc = SQLITE_OK;
+  int iCur;
+  WhereClause tempWC;
+  WhereLoopBuilder sSubBuild;
+  WhereOrSet sSum, sCur;
+  SrcItem *pItem;
+
+  pWC = pBuilder->pWC;
+  pWCEnd = pWC->a + pWC->nTerm;
+  pNew = pBuilder->pNew;
+  memset(&sSum, 0, sizeof(sSum));
+  pItem = pWInfo->pTabList->a + pNew->iTab;
+  iCur = pItem->iCursor;
+
+  /* The multi-index OR optimization does not work for RIGHT and FULL JOIN */
+  if( pItem->fg.jointype & JT_RIGHT ) return SQLITE_OK;
+
+  for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE_OK; pTerm++){
+    if( (pTerm->eOperator & WO_OR)!=0
+     && (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0
+    ){
+      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
+      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
+      WhereTerm *pOrTerm;
+      int once = 1;
+      int i, j;
+
+      sSubBuild = *pBuilder;
+      sSubBuild.pOrSet = &sCur;
+
+      WHERETRACE(0x400, ("Begin processing OR-clause %p\n", pTerm));
+      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
+        if( (pOrTerm->eOperator & WO_AND)!=0 ){
+          sSubBuild.pWC = &pOrTerm->u.pAndInfo->wc;
+        }else if( pOrTerm->leftCursor==iCur ){
+          tempWC.pWInfo = pWC->pWInfo;
+          tempWC.pOuter = pWC;
+          tempWC.op = TK_AND;
+          tempWC.nTerm = 1;
+          tempWC.nBase = 1;
+          tempWC.a = pOrTerm;
+          sSubBuild.pWC = &tempWC;
+        }else{
+          continue;
+        }
+        sCur.n = 0;
+#ifdef WHERETRACE_ENABLED
+        WHERETRACE(0x400, ("OR-term %d of %p has %d subterms:\n",
+                   (int)(pOrTerm-pOrWC->a), pTerm, sSubBuild.pWC->nTerm));
+        if( sqlite3WhereTrace & 0x20000 ){
+          sqlite3WhereClausePrint(sSubBuild.pWC);
+        }
+#endif
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+        if( IsVirtual(pItem->pSTab) ){
+          rc = whereLoopAddVirtual(&sSubBuild, mPrereq, mUnusable);
+        }else
+#endif
+        {
+          rc = whereLoopAddBtree(&sSubBuild, mPrereq);
+        }
+        if( rc==SQLITE_OK ){
+          rc = whereLoopAddOr(&sSubBuild, mPrereq, mUnusable);
+        }
+        testcase( rc==SQLITE_NOMEM && sCur.n>0 );
+        testcase( rc==SQLITE_DONE );
+        if( sCur.n==0 ){
+          sSum.n = 0;
+          break;
+        }else if( once ){
+          whereOrMove(&sSum, &sCur);
+          once = 0;
+        }else{
+          WhereOrSet sPrev;
+          whereOrMove(&sPrev, &sSum);
+          sSum.n = 0;
+          for(i=0; i<sPrev.n; i++){
+            for(j=0; j<sCur.n; j++){
+              whereOrInsert(&sSum, sPrev.a[i].prereq | sCur.a[j].prereq,
+                            sqlite3LogEstAdd(sPrev.a[i].rRun, sCur.a[j].rRun),
+                            sqlite3LogEstAdd(sPrev.a[i].nOut, sCur.a[j].nOut));
+            }
+          }
+        }
+      }
+      pNew->nLTerm = 1;
+      pNew->aLTerm[0] = pTerm;
+      pNew->wsFlags = WHERE_MULTI_OR;
+      pNew->rSetup = 0;
+      pNew->iSortIdx = 0;
+      memset(&pNew->u, 0, sizeof(pNew->u));
+      for(i=0; rc==SQLITE_OK && i<sSum.n; i++){
+        /* TUNING: Currently sSum.a[i].rRun is set to the sum of the costs
+        ** of all sub-scans required by the OR-scan. However, due to rounding
+        ** errors, it may be that the cost of the OR-scan is equal to its
+        ** most expensive sub-scan. Add the smallest possible penalty
+        ** (equivalent to multiplying the cost by 1.07) to ensure that
+        ** this does not happen. Otherwise, for WHERE clauses such as the
+        ** following where there is an index on "y":
+        **
+        **     WHERE likelihood(x=?, 0.99) OR y=?
+        **
+        ** the planner may elect to "OR" together a full-table scan and an
+        ** index lookup. And other similarly odd results.  */
+        pNew->rRun = sSum.a[i].rRun + 1;
+        pNew->nOut = sSum.a[i].nOut;
+        pNew->prereq = sSum.a[i].prereq;
+        rc = whereLoopInsert(pBuilder, pNew);
+      }
+      WHERETRACE(0x400, ("End processing OR-clause %p\n", pTerm));
+    }
+  }
+  return rc;
+}
+
+/*
+** Add all WhereLoop objects for all tables
+*/
+static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
+  WhereInfo *pWInfo = pBuilder->pWInfo;
+  Bitmask mPrereq = 0;
+  Bitmask mPrior = 0;
+  int iTab;
+  SrcList *pTabList = pWInfo->pTabList;
+  SrcItem *pItem;
+  SrcItem *pEnd = &pTabList->a[pWInfo->nLevel];
+  sqlite3 *db = pWInfo->pParse->db;
+  int rc = SQLITE_OK;
+  int bFirstPastRJ = 0;
+  int hasRightJoin = 0;
+  WhereLoop *pNew;
+
+
+  /* Loop over the tables in the join, from left to right */
+  pNew = pBuilder->pNew;
+
+  /* Verify that pNew has already been initialized */
+  assert( pNew->nLTerm==0 );
+  assert( pNew->wsFlags==0 );
+  assert( pNew->nLSlot>=ArraySize(pNew->aLTermSpace) );
+  assert( pNew->aLTerm!=0 );
+
+  pBuilder->iPlanLimit = SQLITE_QUERY_PLANNER_LIMIT;
+  for(iTab=0, pItem=pTabList->a; pItem<pEnd; iTab++, pItem++){
+    Bitmask mUnusable = 0;
+    pNew->iTab = iTab;
+    pBuilder->iPlanLimit += SQLITE_QUERY_PLANNER_LIMIT_INCR;
+    pNew->maskSelf = sqlite3WhereGetMask(&pWInfo->sMaskSet, pItem->iCursor);
+    if( bFirstPastRJ
+     || (pItem->fg.jointype & (JT_OUTER|JT_CROSS|JT_LTORJ))!=0
+    ){
+      /* Add prerequisites to prevent reordering of FROM clause terms
+      ** across CROSS joins and outer joins.  The bFirstPastRJ boolean
+      ** prevents the right operand of a RIGHT JOIN from being swapped with
+      ** other elements even further to the right.
+      **
+      ** The JT_LTORJ case and the hasRightJoin flag work together to
+      ** prevent FROM-clause terms from moving from the right side of
+      ** a LEFT JOIN over to the left side of that join if the LEFT JOIN
+      ** is itself on the left side of a RIGHT JOIN.
+      */
+      if( pItem->fg.jointype & JT_LTORJ ) hasRightJoin = 1;
+      mPrereq |= mPrior;
+      bFirstPastRJ = (pItem->fg.jointype & JT_RIGHT)!=0;
+    }else if( !hasRightJoin ){
+      mPrereq = 0;
+    }
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( IsVirtual(pItem->pSTab) ){
+      SrcItem *p;
+      for(p=&pItem[1]; p<pEnd; p++){
+        if( mUnusable || (p->fg.jointype & (JT_OUTER|JT_CROSS)) ){
+          mUnusable |= sqlite3WhereGetMask(&pWInfo->sMaskSet, p->iCursor);
+        }
+      }
+      rc = whereLoopAddVirtual(pBuilder, mPrereq, mUnusable);
+    }else
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+    {
+      rc = whereLoopAddBtree(pBuilder, mPrereq);
+    }
+    if( rc==SQLITE_OK && pBuilder->pWC->hasOr ){
+      rc = whereLoopAddOr(pBuilder, mPrereq, mUnusable);
+    }
+    mPrior |= pNew->maskSelf;
+    if( rc || db->mallocFailed ){
+      if( rc==SQLITE_DONE ){
+        /* We hit the query planner search limit set by iPlanLimit */
+        sqlite3_log(SQLITE_WARNING, "abbreviated query algorithm search");
+        rc = SQLITE_OK;
+      }else{
+        break;
+      }
+    }
+  }
+
+  whereLoopClear(db, pNew);
+  return rc;
+}
+
+/* Implementation of the order-by-subquery optimization:
+**
+** WhereLoop pLoop, which the iLoop-th term of the nested loop, is really
+** a subquery or CTE that has an ORDER BY clause.  See if any of the terms
+** in the subquery ORDER BY clause will satisfy pOrderBy from the outer
+** query.  Mark off all satisfied terms (by setting bits in *pOBSat) and
+** return TRUE if they do.  If not, return false.
+**
+** Example:
+**
+**    CREATE TABLE t1(a,b,c, PRIMARY KEY(a,b));
+**    CREATE TABLE t2(x,y);
+**    WITH t3(p,q) AS MATERIALIZED (SELECT x+y, x-y FROM t2 ORDER BY x+y)
+**       SELECT * FROM t3 JOIN t1 ON a=q ORDER BY p, b;
+**
+** The CTE named "t3" comes out in the natural order of "p", so the first
+** first them of "ORDER BY p,b" is satisfied by a sequential scan of "t3"
+** and sorting only needs to occur on the second term "b".
+**
+** Limitations:
+**
+** (1)  The optimization is not applied if the outer ORDER BY contains
+**      a COLLATE clause.  The optimization might be applied if the
+**      outer ORDER BY uses NULLS FIRST, NULLS LAST, ASC, and/or DESC as
+**      long as the subquery ORDER BY does the same.  But if the
+**      outer ORDER BY uses COLLATE, even a redundant COLLATE, the
+**      optimization is bypassed.
+**
+** (2)  The subquery ORDER BY terms must exactly match subquery result
+**      columns, including any COLLATE annotations.  This routine relies
+**      on iOrderByCol to do matching between order by terms and result
+**      columns, and iOrderByCol will not be set if the result column
+**      and ORDER BY collations differ.
+**
+** (3)  The subquery and outer ORDER BY can be in opposite directions as
+**      long as  the subquery is materialized.  If the subquery is
+**      implemented as a co-routine, the sort orders must be in the same
+**      direction because there is no way to run a co-routine backwards.
+*/
+static SQLITE_NOINLINE int wherePathMatchSubqueryOB(
+  WhereInfo *pWInfo,      /* The WHERE clause */
+  WhereLoop *pLoop,       /* The nested loop term that is a subquery */
+  int iLoop,              /* Which level of the nested loop.  0==outermost */
+  int iCur,               /* Cursor used by the this loop */
+  ExprList *pOrderBy,     /* The ORDER BY clause on the whole query */
+  Bitmask *pRevMask,      /* When loops need to go in reverse order */
+  Bitmask *pOBSat         /* Which terms of pOrderBy are satisfied so far */
+){
+  int iOB;                /* Index into pOrderBy->a[] */
+  int jSub;               /* Index into pSubOB->a[] */
+  u8 rev = 0;             /* True if iOB and jSub sort in opposite directions */
+  u8 revIdx = 0;          /* Sort direction for jSub */
+  Expr *pOBExpr;          /* Current term of outer ORDER BY */
+  ExprList *pSubOB;       /* Complete ORDER BY on the subquery */
+
+  pSubOB = pLoop->u.btree.pOrderBy;
+  assert( pSubOB!=0 );
+  for(iOB=0; (MASKBIT(iOB) & *pOBSat)!=0; iOB++){}
+  for(jSub=0; jSub<pSubOB->nExpr && iOB<pOrderBy->nExpr; jSub++, iOB++){
+    if( pSubOB->a[jSub].u.x.iOrderByCol==0 ) break;
+    pOBExpr = pOrderBy->a[iOB].pExpr;
+    if( pOBExpr->op!=TK_COLUMN && pOBExpr->op!=TK_AGG_COLUMN ) break;
+    if( pOBExpr->iTable!=iCur ) break;
+    if( pOBExpr->iColumn!=pSubOB->a[jSub].u.x.iOrderByCol-1 ) break;
+    if( (pWInfo->wctrlFlags & WHERE_GROUPBY)==0 ){
+      u8 sfOB = pOrderBy->a[iOB].fg.sortFlags;   /* sortFlags for iOB */
+      u8 sfSub = pSubOB->a[jSub].fg.sortFlags;   /* sortFlags for jSub */
+      if( (sfSub & KEYINFO_ORDER_BIGNULL) != (sfOB & KEYINFO_ORDER_BIGNULL) ){
+        break;
+      }
+      revIdx = sfSub & KEYINFO_ORDER_DESC;
+      if( jSub>0 ){
+        if( (rev^revIdx)!=(sfOB & KEYINFO_ORDER_DESC) ){
+          break;
+        }
+      }else{
+        rev = revIdx ^ (sfOB & KEYINFO_ORDER_DESC);
+        if( rev ){
+          if( (pLoop->wsFlags & WHERE_COROUTINE)!=0 ){
+            /* Cannot run a co-routine in reverse order */
+            break;
+          }
+          *pRevMask |= MASKBIT(iLoop);
+        }
+      }
+    }
+    *pOBSat |= MASKBIT(iOB);
+  }
+  return jSub>0;
+}
+
+/*
+** Examine a WherePath (with the addition of the extra WhereLoop of the 6th
+** parameters) to see if it outputs rows in the requested ORDER BY
+** (or GROUP BY) without requiring a separate sort operation.  Return N:
+**
+**   N>0:   N terms of the ORDER BY clause are satisfied
+**   N==0:  No terms of the ORDER BY clause are satisfied
+**   N<0:   Unknown yet how many terms of ORDER BY might be satisfied.
+**
+** Note that processing for WHERE_GROUPBY and WHERE_DISTINCTBY is not as
+** strict.  With GROUP BY and DISTINCT the only requirement is that
+** equivalent rows appear immediately adjacent to one another.  GROUP BY
+** and DISTINCT do not require rows to appear in any particular order as long
+** as equivalent rows are grouped together.  Thus for GROUP BY and DISTINCT
+** the pOrderBy terms can be matched in any order.  With ORDER BY, the
+** pOrderBy terms must be matched in strict left-to-right order.
+*/
+static i8 wherePathSatisfiesOrderBy(
+  WhereInfo *pWInfo,    /* The WHERE clause */
+  ExprList *pOrderBy,   /* ORDER BY or GROUP BY or DISTINCT clause to check */
+  WherePath *pPath,     /* The WherePath to check */
+  u16 wctrlFlags,       /* WHERE_GROUPBY or _DISTINCTBY or _ORDERBY_LIMIT */
+  u16 nLoop,            /* Number of entries in pPath->aLoop[] */
+  WhereLoop *pLast,     /* Add this WhereLoop to the end of pPath->aLoop[] */
+  Bitmask *pRevMask     /* OUT: Mask of WhereLoops to run in reverse order */
+){
+  u8 revSet;            /* True if rev is known */
+  u8 rev;               /* Composite sort order */
+  u8 revIdx;            /* Index sort order */
+  u8 isOrderDistinct;   /* All prior WhereLoops are order-distinct */
+  u8 distinctColumns;   /* True if the loop has UNIQUE NOT NULL columns */
+  u8 isMatch;           /* iColumn matches a term of the ORDER BY clause */
+  u16 eqOpMask;         /* Allowed equality operators */
+  u16 nKeyCol;          /* Number of key columns in pIndex */
+  u16 nColumn;          /* Total number of ordered columns in the index */
+  u16 nOrderBy;         /* Number terms in the ORDER BY clause */
+  int iLoop;            /* Index of WhereLoop in pPath being processed */
+  int i, j;             /* Loop counters */
+  int iCur;             /* Cursor number for current WhereLoop */
+  int iColumn;          /* A column number within table iCur */
+  WhereLoop *pLoop = 0; /* Current WhereLoop being processed. */
+  WhereTerm *pTerm;     /* A single term of the WHERE clause */
+  Expr *pOBExpr;        /* An expression from the ORDER BY clause */
+  CollSeq *pColl;       /* COLLATE function from an ORDER BY clause term */
+  Index *pIndex;        /* The index associated with pLoop */
+  sqlite3 *db = pWInfo->pParse->db;  /* Database connection */
+  Bitmask obSat = 0;    /* Mask of ORDER BY terms satisfied so far */
+  Bitmask obDone;       /* Mask of all ORDER BY terms */
+  Bitmask orderDistinctMask;  /* Mask of all well-ordered loops */
+  Bitmask ready;              /* Mask of inner loops */
+
+  /*
+  ** We say the WhereLoop is "one-row" if it generates no more than one
+  ** row of output.  A WhereLoop is one-row if all of the following are true:
+  **  (a) All index columns match with WHERE_COLUMN_EQ.
+  **  (b) The index is unique
+  ** Any WhereLoop with an WHERE_COLUMN_EQ constraint on the rowid is one-row.
+  ** Every one-row WhereLoop will have the WHERE_ONEROW bit set in wsFlags.
+  **
+  ** We say the WhereLoop is "order-distinct" if the set of columns from
+  ** that WhereLoop that are in the ORDER BY clause are different for every
+  ** row of the WhereLoop.  Every one-row WhereLoop is automatically
+  ** order-distinct.   A WhereLoop that has no columns in the ORDER BY clause
+  ** is not order-distinct. To be order-distinct is not quite the same as being
+  ** UNIQUE since a UNIQUE column or index can have multiple rows that
+  ** are NULL and NULL values are equivalent for the purpose of order-distinct.
+  ** To be order-distinct, the columns must be UNIQUE and NOT NULL.
+  **
+  ** The rowid for a table is always UNIQUE and NOT NULL so whenever the
+  ** rowid appears in the ORDER BY clause, the corresponding WhereLoop is
+  ** automatically order-distinct.
+  */
+
+  assert( pOrderBy!=0 );
+  if( nLoop && OptimizationDisabled(db, SQLITE_OrderByIdxJoin) ) return 0;
+
+  nOrderBy = pOrderBy->nExpr;
+  testcase( nOrderBy==BMS-1 );
+  if( nOrderBy>BMS-1 ) return 0;  /* Cannot optimize overly large ORDER BYs */
+  isOrderDistinct = 1;
+  obDone = MASKBIT(nOrderBy)-1;
+  orderDistinctMask = 0;
+  ready = 0;
+  eqOpMask = WO_EQ | WO_IS | WO_ISNULL;
+  if( wctrlFlags & (WHERE_ORDERBY_LIMIT|WHERE_ORDERBY_MAX|WHERE_ORDERBY_MIN) ){
+    eqOpMask |= WO_IN;
+  }
+  for(iLoop=0; isOrderDistinct && obSat<obDone && iLoop<=nLoop; iLoop++){
+    if( iLoop>0 ) ready |= pLoop->maskSelf;
+    if( iLoop<nLoop ){
+      pLoop = pPath->aLoop[iLoop];
+      if( wctrlFlags & WHERE_ORDERBY_LIMIT ) continue;
+    }else{
+      pLoop = pLast;
+    }
+    if( pLoop->wsFlags & WHERE_VIRTUALTABLE ){
+      if( pLoop->u.vtab.isOrdered
+       && ((wctrlFlags&(WHERE_DISTINCTBY|WHERE_SORTBYGROUP))!=WHERE_DISTINCTBY)
+      ){
+        obSat = obDone;
+      }
+      break;
+    }else if( wctrlFlags & WHERE_DISTINCTBY ){
+      pLoop->u.btree.nDistinctCol = 0;
+    }
+    iCur = pWInfo->pTabList->a[pLoop->iTab].iCursor;
+
+    /* Mark off any ORDER BY term X that is a column in the table of
+    ** the current loop for which there is term in the WHERE
+    ** clause of the form X IS NULL or X=? that reference only outer
+    ** loops.
+    */
+    for(i=0; i<nOrderBy; i++){
+      if( MASKBIT(i) & obSat ) continue;
+      pOBExpr = sqlite3ExprSkipCollateAndLikely(pOrderBy->a[i].pExpr);
+      if( NEVER(pOBExpr==0) ) continue;
+      if( pOBExpr->op!=TK_COLUMN && pOBExpr->op!=TK_AGG_COLUMN ) continue;
+      if( pOBExpr->iTable!=iCur ) continue;
+      pTerm = sqlite3WhereFindTerm(&pWInfo->sWC, iCur, pOBExpr->iColumn,
+                       ~ready, eqOpMask, 0);
+      if( pTerm==0 ) continue;
+      if( pTerm->eOperator==WO_IN ){
+        /* IN terms are only valid for sorting in the ORDER BY LIMIT
+        ** optimization, and then only if they are actually used
+        ** by the query plan */
+        assert( wctrlFlags &
+               (WHERE_ORDERBY_LIMIT|WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX) );
+        for(j=0; j<pLoop->nLTerm && pTerm!=pLoop->aLTerm[j]; j++){}
+        if( j>=pLoop->nLTerm ) continue;
+      }
+      if( (pTerm->eOperator&(WO_EQ|WO_IS))!=0 && pOBExpr->iColumn>=0 ){
+        Parse *pParse = pWInfo->pParse;
+        CollSeq *pColl1 = sqlite3ExprNNCollSeq(pParse, pOrderBy->a[i].pExpr);
+        CollSeq *pColl2 = sqlite3ExprCompareCollSeq(pParse, pTerm->pExpr);
+        assert( pColl1 );
+        if( pColl2==0 || sqlite3StrICmp(pColl1->zName, pColl2->zName) ){
+          continue;
+        }
+        testcase( pTerm->pExpr->op==TK_IS );
+      }
+      obSat |= MASKBIT(i);
+    }
+
+    if( (pLoop->wsFlags & WHERE_ONEROW)==0 ){
+      if( pLoop->wsFlags & WHERE_IPK ){
+        if( pLoop->u.btree.pOrderBy
+         && OptimizationEnabled(db, SQLITE_OrderBySubq)
+         &&  wherePathMatchSubqueryOB(pWInfo,pLoop,iLoop,iCur,
+                                     pOrderBy,pRevMask, &obSat)
+        ){
+          nColumn = 0;
+          isOrderDistinct = 0;
+        }else{
+          nColumn = 1;
+        }
+        pIndex = 0;
+        nKeyCol = 0;
+      }else if( (pIndex = pLoop->u.btree.pIndex)==0 || pIndex->bUnordered ){
+        return 0;
+      }else{
+        nKeyCol = pIndex->nKeyCol;
+        nColumn = pIndex->nColumn;
+        assert( nColumn==nKeyCol+1 || !HasRowid(pIndex->pTable) );
+        assert( pIndex->aiColumn[nColumn-1]==XN_ROWID
+                          || !HasRowid(pIndex->pTable));
+        /* All relevant terms of the index must also be non-NULL in order
+        ** for isOrderDistinct to be true.  So the isOrderDistinct value
+        ** computed here might be a false positive.  Corrections will be
+        ** made at tag-20210426-1 below */
+        isOrderDistinct = IsUniqueIndex(pIndex)
+                          && (pLoop->wsFlags & WHERE_SKIPSCAN)==0;
+      }
+
+      /* Loop through all columns of the index and deal with the ones
+      ** that are not constrained by == or IN.
+      */
+      rev = revSet = 0;
+      distinctColumns = 0;
+      for(j=0; j<nColumn; j++){
+        u8 bOnce = 1; /* True to run the ORDER BY search loop */
+
+        assert( j>=pLoop->u.btree.nEq
+            || (pLoop->aLTerm[j]==0)==(j<pLoop->nSkip)
+        );
+        if( j<pLoop->u.btree.nEq && j>=pLoop->nSkip ){
+          u16 eOp = pLoop->aLTerm[j]->eOperator;
+
+          /* Skip over == and IS and ISNULL terms.  (Also skip IN terms when
+          ** doing WHERE_ORDERBY_LIMIT processing).  Except, IS and ISNULL
+          ** terms imply that the index is not UNIQUE NOT NULL in which case
+          ** the loop need to be marked as not order-distinct because it can
+          ** have repeated NULL rows.
+          **
+          ** If the current term is a column of an ((?,?) IN (SELECT...))
+          ** expression for which the SELECT returns more than one column,
+          ** check that it is the only column used by this loop. Otherwise,
+          ** if it is one of two or more, none of the columns can be
+          ** considered to match an ORDER BY term.
+          */
+          if( (eOp & eqOpMask)!=0 ){
+            if( eOp & (WO_ISNULL|WO_IS) ){
+              testcase( eOp & WO_ISNULL );
+              testcase( eOp & WO_IS );
+              testcase( isOrderDistinct );
+              isOrderDistinct = 0;
+            }
+            continue;
+          }else if( ALWAYS(eOp & WO_IN) ){
+            /* ALWAYS() justification: eOp is an equality operator due to the
+            ** j<pLoop->u.btree.nEq constraint above.  Any equality other
+            ** than WO_IN is captured by the previous "if".  So this one
+            ** always has to be WO_IN. */
+            Expr *pX = pLoop->aLTerm[j]->pExpr;
+            for(i=j+1; i<pLoop->u.btree.nEq; i++){
+              if( pLoop->aLTerm[i]->pExpr==pX ){
+                assert( (pLoop->aLTerm[i]->eOperator & WO_IN) );
+                bOnce = 0;
+                break;
+              }
+            }
+          }
+        }
+
+        /* Get the column number in the table (iColumn) and sort order
+        ** (revIdx) for the j-th column of the index.
+        */
+        if( pIndex ){
+          iColumn = pIndex->aiColumn[j];
+          revIdx = pIndex->aSortOrder[j] & KEYINFO_ORDER_DESC;
+          if( iColumn==pIndex->pTable->iPKey ) iColumn = XN_ROWID;
+        }else{
+          iColumn = XN_ROWID;
+          revIdx = 0;
+        }
+
+        /* An unconstrained column that might be NULL means that this
+        ** WhereLoop is not well-ordered.  tag-20210426-1
+        */
+        if( isOrderDistinct ){
+          if( iColumn>=0
+           && j>=pLoop->u.btree.nEq
+           && pIndex->pTable->aCol[iColumn].notNull==0
+          ){
+            isOrderDistinct = 0;
+          }
+          if( iColumn==XN_EXPR ){
+            isOrderDistinct = 0;
+          }
+        }
+
+        /* Find the ORDER BY term that corresponds to the j-th column
+        ** of the index and mark that ORDER BY term having been satisfied.
+        */
+        isMatch = 0;
+        for(i=0; bOnce && i<nOrderBy; i++){
+          if( MASKBIT(i) & obSat ) continue;
+          pOBExpr = sqlite3ExprSkipCollateAndLikely(pOrderBy->a[i].pExpr);
+          testcase( wctrlFlags & WHERE_GROUPBY );
+          testcase( wctrlFlags & WHERE_DISTINCTBY );
+          if( NEVER(pOBExpr==0) ) continue;
+          if( (wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY))==0 ) bOnce = 0;
+          if( iColumn>=XN_ROWID ){
+            if( pOBExpr->op!=TK_COLUMN && pOBExpr->op!=TK_AGG_COLUMN ) continue;
+            if( pOBExpr->iTable!=iCur ) continue;
+            if( pOBExpr->iColumn!=iColumn ) continue;
+          }else{
+            Expr *pIxExpr = pIndex->aColExpr->a[j].pExpr;
+            if( sqlite3ExprCompareSkip(pOBExpr, pIxExpr, iCur) ){
+              continue;
+            }
+          }
+          if( iColumn!=XN_ROWID ){
+            pColl = sqlite3ExprNNCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
+            if( sqlite3StrICmp(pColl->zName, pIndex->azColl[j])!=0 ) continue;
+          }
+          if( wctrlFlags & WHERE_DISTINCTBY ){
+            pLoop->u.btree.nDistinctCol = j+1;
+          }
+          isMatch = 1;
+          break;
+        }
+        if( isMatch && (wctrlFlags & WHERE_GROUPBY)==0 ){
+          /* Make sure the sort order is compatible in an ORDER BY clause.
+          ** Sort order is irrelevant for a GROUP BY clause. */
+          if( revSet ){
+            if( (rev ^ revIdx)
+                           != (pOrderBy->a[i].fg.sortFlags&KEYINFO_ORDER_DESC)
+            ){
+              isMatch = 0;
+            }
+          }else{
+            rev = revIdx ^ (pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_DESC);
+            if( rev ) *pRevMask |= MASKBIT(iLoop);
+            revSet = 1;
+          }
+        }
+        if( isMatch && (pOrderBy->a[i].fg.sortFlags & KEYINFO_ORDER_BIGNULL) ){
+          if( j==pLoop->u.btree.nEq ){
+            pLoop->wsFlags |= WHERE_BIGNULL_SORT;
+          }else{
+            isMatch = 0;
+          }
+        }
+        if( isMatch ){
+          if( iColumn==XN_ROWID ){
+            testcase( distinctColumns==0 );
+            distinctColumns = 1;
+          }
+          obSat |= MASKBIT(i);
+        }else{
+          /* No match found */
+          if( j==0 || j<nKeyCol ){
+            testcase( isOrderDistinct!=0 );
+            isOrderDistinct = 0;
+          }
+          break;
+        }
+      } /* end Loop over all index columns */
+      if( distinctColumns ){
+        testcase( isOrderDistinct==0 );
+        isOrderDistinct = 1;
+      }
+    } /* end-if not one-row */
+
+    /* Mark off any other ORDER BY terms that reference pLoop */
+    if( isOrderDistinct ){
+      orderDistinctMask |= pLoop->maskSelf;
+      for(i=0; i<nOrderBy; i++){
+        Expr *p;
+        Bitmask mTerm;
+        if( MASKBIT(i) & obSat ) continue;
+        p = pOrderBy->a[i].pExpr;
+        mTerm = sqlite3WhereExprUsage(&pWInfo->sMaskSet,p);
+        if( mTerm==0 && !sqlite3ExprIsConstant(0,p) ) continue;
+        if( (mTerm&~orderDistinctMask)==0 ){
+          obSat |= MASKBIT(i);
+        }
+      }
+    }
+  } /* End the loop over all WhereLoops from outer-most down to inner-most */
+  if( obSat==obDone ) return (i8)nOrderBy;
+  if( !isOrderDistinct ){
+    for(i=nOrderBy-1; i>0; i--){
+      Bitmask m = ALWAYS(i<BMS) ? MASKBIT(i) - 1 : 0;
+      if( (obSat&m)==m ) return i;
+    }
+    return 0;
+  }
+  return -1;
+}
+
+
+/*
+** If the WHERE_GROUPBY flag is set in the mask passed to sqlite3WhereBegin(),
+** the planner assumes that the specified pOrderBy list is actually a GROUP
+** BY clause - and so any order that groups rows as required satisfies the
+** request.
+**
+** Normally, in this case it is not possible for the caller to determine
+** whether or not the rows are really being delivered in sorted order, or
+** just in some other order that provides the required grouping. However,
+** if the WHERE_SORTBYGROUP flag is also passed to sqlite3WhereBegin(), then
+** this function may be called on the returned WhereInfo object. It returns
+** true if the rows really will be sorted in the specified order, or false
+** otherwise.
+**
+** For example, assuming:
+**
+**   CREATE INDEX i1 ON t1(x, Y);
+**
+** then
+**
+**   SELECT * FROM t1 GROUP BY x,y ORDER BY x,y;   -- IsSorted()==1
+**   SELECT * FROM t1 GROUP BY y,x ORDER BY y,x;   -- IsSorted()==0
+*/
+SQLITE_PRIVATE int sqlite3WhereIsSorted(WhereInfo *pWInfo){
+  assert( pWInfo->wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY) );
+  assert( pWInfo->wctrlFlags & WHERE_SORTBYGROUP );
+  return pWInfo->sorted;
+}
+
+#ifdef WHERETRACE_ENABLED
+/* For debugging use only: */
+static const char *wherePathName(WherePath *pPath, int nLoop, WhereLoop *pLast){
+  static char zName[65];
+  int i;
+  for(i=0; i<nLoop; i++){ zName[i] = pPath->aLoop[i]->cId; }
+  if( pLast ) zName[i++] = pLast->cId;
+  zName[i] = 0;
+  return zName;
+}
+#endif
+
+/*
+** Return the cost of sorting nRow rows, assuming that the keys have
+** nOrderby columns and that the first nSorted columns are already in
+** order.
+*/
+static LogEst whereSortingCost(
+  WhereInfo *pWInfo, /* Query planning context */
+  LogEst nRow,       /* Estimated number of rows to sort */
+  int nOrderBy,      /* Number of ORDER BY clause terms */
+  int nSorted        /* Number of initial ORDER BY terms naturally in order */
+){
+  /* Estimated cost of a full external sort, where N is
+  ** the number of rows to sort is:
+  **
+  **   cost = (K * N * log(N)).
+  **
+  ** Or, if the order-by clause has X terms but only the last Y
+  ** terms are out of order, then block-sorting will reduce the
+  ** sorting cost to:
+  **
+  **   cost = (K * N * log(N)) * (Y/X)
+  **
+  ** The constant K is at least 2.0 but will be larger if there are a
+  ** large number of columns to be sorted, as the sorting time is
+  ** proportional to the amount of content to be sorted.  The algorithm
+  ** does not currently distinguish between fat columns (BLOBs and TEXTs)
+  ** and skinny columns (INTs).  It just uses the number of columns as
+  ** an approximation for the row width.
+  **
+  ** And extra factor of 2.0 or 3.0 is added to the sorting cost if the sort
+  ** is built using OP_IdxInsert and OP_Sort rather than with OP_SorterInsert.
+  */
+  LogEst rSortCost, nCol;
+  assert( pWInfo->pSelect!=0 );
+  assert( pWInfo->pSelect->pEList!=0 );
+  /* TUNING: sorting cost proportional to the number of output columns: */
+  nCol = sqlite3LogEst((pWInfo->pSelect->pEList->nExpr+59)/30);
+  rSortCost = nRow + nCol;
+  if( nSorted>0 ){
+    /* Scale the result by (Y/X) */
+    rSortCost += sqlite3LogEst((nOrderBy-nSorted)*100/nOrderBy) - 66;
+  }
+
+  /* Multiple by log(M) where M is the number of output rows.
+  ** Use the LIMIT for M if it is smaller.  Or if this sort is for
+  ** a DISTINCT operator, M will be the number of distinct output
+  ** rows, so fudge it downwards a bit.
+  */
+  if( (pWInfo->wctrlFlags & WHERE_USE_LIMIT)!=0 ){
+    rSortCost += 10;       /* TUNING: Extra 2.0x if using LIMIT */
+    if( nSorted!=0 ){
+      rSortCost += 6;      /* TUNING: Extra 1.5x if also using partial sort */
+    }
+    if( pWInfo->iLimit<nRow ){
+      nRow = pWInfo->iLimit;
+    }
+  }else if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT) ){
+    /* TUNING: In the sort for a DISTINCT operator, assume that the DISTINCT
+    ** reduces the number of output rows by a factor of 2 */
+    if( nRow>10 ){ nRow -= 10;  assert( 10==sqlite3LogEst(2) ); }
+  }
+  rSortCost += estLog(nRow);
+  return rSortCost;
+}
+
+/*
+** Compute the maximum number of paths in the solver algorithm, for
+** queries that have three or more terms in the FROM clause.  Queries with
+** two or fewer FROM clause terms are handled by the caller.
+**
+** Query planning is NP-hard.  We must limit the number of paths at
+** each step of the solver search algorithm to avoid exponential behavior.
+**
+** The value returned is a tuning parameter.  Currently the value is:
+**
+**     18    for star queries
+**     12    otherwise
+**
+** For the purposes of this heuristic, a star-query is defined as a query
+** with a large central table that is joined using an INNER JOIN,
+** not CROSS or OUTER JOINs, against four or more smaller tables.
+** The central table is called the "fact" table.  The smaller tables
+** that get joined are "dimension tables".  Also, any table that is
+** self-joined cannot be a dimension table; we assume that dimension
+** tables may only be joined against fact tables.
+**
+** SIDE EFFECT:  (and really the whole point of this subroutine)
+**
+** If pWInfo describes a star-query, then the cost for SCANs of dimension
+** WhereLoops is increased to be slightly larger than the cost of a SCAN
+** in the fact table.  Only SCAN costs are increased.  SEARCH costs are
+** unchanged. This heuristic helps keep fact tables in outer loops. Without
+** this heuristic, paths with fact tables in outer loops tend to get pruned
+** by the mxChoice limit on the number of paths, resulting in poor query
+** plans.  See the starschema1.test test module for examples of queries
+** that need this heuristic to find good query plans.
+**
+** This heuristic can be completely disabled, so that no query is
+** considered a star-query, using SQLITE_TESTCTRL_OPTIMIZATION to
+** disable the SQLITE_StarQuery optimization.  In the CLI, the command
+** to do that is:  ".testctrl opt -starquery".
+**
+** HISTORICAL NOTES:
+**
+** This optimization was first added on 2024-05-09 by check-in 38db9b5c83d.
+** The original optimization reduced the cost and output size estimate for
+** fact tables to help them move to outer loops.  But months later (as people
+** started upgrading) performance regression reports started caming in,
+** including:
+**
+**    forum post b18ef983e68d06d1 (2024-12-21)
+**    forum post 0025389d0860af82 (2025-01-14)
+**    forum post d87570a145599033 (2025-01-17)
+**
+** To address these, the criteria for a star-query was tightened to exclude
+** cases where the fact and dimensions are separated by an outer join, and
+** the affect of star-schema detection was changed to increase the rRun cost
+** on just full table scans of dimension tables, rather than reducing costs
+** in the all access methods of the fact table.
+*/
+static int computeMxChoice(WhereInfo *pWInfo){
+  int nLoop = pWInfo->nLevel;    /* Number of terms in the join */
+  WhereLoop *pWLoop;             /* For looping over WhereLoops */
+
+#ifdef SQLITE_DEBUG
+  /* The star-query detection code below makes use of the following
+  ** properties of the WhereLoop list, so verify them before
+  ** continuing:
+  **    (1)  .maskSelf is the bitmask corresponding to .iTab
+  **    (2)  The WhereLoop list is in ascending .iTab order
+  */
+  for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
+    assert( pWLoop->maskSelf==MASKBIT(pWLoop->iTab) );
+    assert( pWLoop->pNextLoop==0 || pWLoop->iTab<=pWLoop->pNextLoop->iTab );
+  }
+#endif /* SQLITE_DEBUG */
+
+  if( nLoop>=5
+   && !pWInfo->bStarDone
+   && OptimizationEnabled(pWInfo->pParse->db, SQLITE_StarQuery)
+  ){
+    SrcItem *aFromTabs;    /* All terms of the FROM clause */
+    int iFromIdx;          /* Term of FROM clause is the candidate fact-table */
+    Bitmask m;             /* Bitmask for candidate fact-table */
+    Bitmask mSelfJoin = 0; /* Tables that cannot be dimension tables */
+    WhereLoop *pStart;     /* Where to start searching for dimension-tables */
+
+    pWInfo->bStarDone = 1; /* Only do this computation once */
+
+    /* Look for fact tables with four or more dimensions where the
+    ** dimension tables are not separately from the fact tables by an outer
+    ** or cross join.  Adjust cost weights if found.
+    */
+    assert( !pWInfo->bStarUsed );
+    aFromTabs = pWInfo->pTabList->a;
+    pStart = pWInfo->pLoops;
+    for(iFromIdx=0, m=1; iFromIdx<nLoop; iFromIdx++, m<<=1){
+      int nDep = 0;             /* Number of dimension tables */
+      LogEst mxRun;             /* Maximum SCAN cost of a fact table */
+      Bitmask mSeen = 0;        /* Mask of dimension tables */
+      SrcItem *pFactTab;        /* The candidate fact table */
+
+      pFactTab = aFromTabs + iFromIdx;
+      if( (pFactTab->fg.jointype & (JT_OUTER|JT_CROSS))!=0 ){
+        /* If the candidate fact-table is the right table of an outer join
+        ** restrict the search for dimension-tables to be tables to the right
+        ** of the fact-table. */
+        if( iFromIdx+4 > nLoop ) break;  /* Impossible to reach nDep>=4 */
+        while( pStart && pStart->iTab<=iFromIdx ){
+          pStart = pStart->pNextLoop;
+        }
+      }
+      for(pWLoop=pStart; pWLoop; pWLoop=pWLoop->pNextLoop){
+        if( (aFromTabs[pWLoop->iTab].fg.jointype & (JT_OUTER|JT_CROSS))!=0 ){
+          /* Fact-tables and dimension-tables cannot be separated by an
+          ** outer join (at least for the definition of fact- and dimension-
+          ** used by this heuristic). */
+          break;
+        }
+        if( (pWLoop->prereq & m)!=0        /* pWInfo depends on iFromIdx */
+         && (pWLoop->maskSelf & mSeen)==0  /* pWInfo not already a dependency */
+         && (pWLoop->maskSelf & mSelfJoin)==0 /* Not a self-join */
+        ){
+          if( aFromTabs[pWLoop->iTab].pSTab==pFactTab->pSTab ){
+            mSelfJoin |= m;
+          }else{
+            nDep++;
+            mSeen |= pWLoop->maskSelf;
+          }
+        }
+      }
+      if( nDep<=3 ) continue;
+
+      /* If we reach this point, it means that pFactTab is a fact table
+      ** with four or more dimensions connected by inner joins.  Proceed
+      ** to make cost adjustments. */
+
+#ifdef WHERETRACE_ENABLED
+      /* Make sure rStarDelta values are initialized */
+      if( !pWInfo->bStarUsed ){
+        for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
+          pWLoop->rStarDelta = 0;
+        }
+      }
+#endif
+      pWInfo->bStarUsed = 1;
+
+      /* Compute the maximum cost of any WhereLoop for the
+      ** fact table plus one epsilon */
+      mxRun = LOGEST_MIN;
+      for(pWLoop=pStart; pWLoop; pWLoop=pWLoop->pNextLoop){
+        if( pWLoop->iTab<iFromIdx ) continue;
+        if( pWLoop->iTab>iFromIdx ) break;
+        if( pWLoop->rRun>mxRun ) mxRun = pWLoop->rRun;
+      }
+      if( ALWAYS(mxRun<LOGEST_MAX) ) mxRun++;
+
+      /* Increase the cost of table scans for dimension tables to be
+      ** slightly more than the maximum cost of the fact table */
+      for(pWLoop=pStart; pWLoop; pWLoop=pWLoop->pNextLoop){
+        if( (pWLoop->maskSelf & mSeen)==0 ) continue;
+        if( pWLoop->nLTerm ) continue;
+        if( pWLoop->rRun<mxRun ){
+#ifdef WHERETRACE_ENABLED /* 0x80000 */
+          if( sqlite3WhereTrace & 0x80000 ){
+            SrcItem *pDim = aFromTabs + pWLoop->iTab;
+            sqlite3DebugPrintf(
+              "Increase SCAN cost of dimension %s(%d) of fact %s(%d) to %d\n",
+              pDim->zAlias ? pDim->zAlias: pDim->pSTab->zName, pWLoop->iTab,
+              pFactTab->zAlias ? pFactTab->zAlias : pFactTab->pSTab->zName,
+              iFromIdx, mxRun
+            );
+          }
+          pWLoop->rStarDelta = mxRun - pWLoop->rRun;
+#endif /* WHERETRACE_ENABLED */
+          pWLoop->rRun = mxRun;
+        }
+      }
+    }
+#ifdef WHERETRACE_ENABLED /* 0x80000 */
+    if( (sqlite3WhereTrace & 0x80000)!=0 && pWInfo->bStarUsed ){
+      sqlite3DebugPrintf("WhereLoops changed by star-query heuristic:\n");
+      for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
+        if( pWLoop->rStarDelta ){
+          sqlite3WhereLoopPrint(pWLoop, &pWInfo->sWC);
+        }
+      }
+    }
+#endif
+  }
+  return pWInfo->bStarUsed ? 18 : 12;
+}
+
+/*
+** Two WhereLoop objects, pCandidate and pBaseline, are known to have the
+** same cost.  Look deep into each to see if pCandidate is even slightly
+** better than pBaseline.  Return false if it is, if pCandidate is is preferred.
+** Return true if pBaseline is preferred or if we cannot tell the difference.
+**
+**    Result       Meaning
+**    --------     ----------------------------------------------------------
+**    true         We cannot tell the difference in pCandidate and pBaseline
+**    false        pCandidate seems like a better choice than pBaseline
+*/
+static SQLITE_NOINLINE int whereLoopIsNoBetter(
+  const WhereLoop *pCandidate,
+  const WhereLoop *pBaseline
+){
+  if( (pCandidate->wsFlags & WHERE_INDEXED)==0 ) return 1;
+  if( (pBaseline->wsFlags & WHERE_INDEXED)==0 ) return 1;
+  if( pCandidate->u.btree.pIndex->szIdxRow <
+        pBaseline->u.btree.pIndex->szIdxRow ) return 0;
+  return 1;
+}
+
+/*
+** Given the list of WhereLoop objects at pWInfo->pLoops, this routine
+** attempts to find the lowest cost path that visits each WhereLoop
+** once.  This path is then loaded into the pWInfo->a[].pWLoop fields.
+**
+** Assume that the total number of output rows that will need to be sorted
+** will be nRowEst (in the 10*log2 representation).  Or, ignore sorting
+** costs if nRowEst==0.
+**
+** Return SQLITE_OK on success or SQLITE_NOMEM of a memory allocation
+** error occurs.
+*/
+static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
+  int mxChoice;             /* Maximum number of simultaneous paths tracked */
+  int nLoop;                /* Number of terms in the join */
+  Parse *pParse;            /* Parsing context */
+  int iLoop;                /* Loop counter over the terms of the join */
+  int ii, jj;               /* Loop counters */
+  int mxI = 0;              /* Index of next entry to replace */
+  int nOrderBy;             /* Number of ORDER BY clause terms */
+  LogEst mxCost = 0;        /* Maximum cost of a set of paths */
+  LogEst mxUnsort = 0;      /* Maximum unsorted cost of a set of path */
+  int nTo, nFrom;           /* Number of valid entries in aTo[] and aFrom[] */
+  WherePath *aFrom;         /* All nFrom paths at the previous level */
+  WherePath *aTo;           /* The nTo best paths at the current level */
+  WherePath *pFrom;         /* An element of aFrom[] that we are working on */
+  WherePath *pTo;           /* An element of aTo[] that we are working on */
+  WhereLoop *pWLoop;        /* One of the WhereLoop objects */
+  WhereLoop **pX;           /* Used to divy up the pSpace memory */
+  LogEst *aSortCost = 0;    /* Sorting and partial sorting costs */
+  char *pSpace;             /* Temporary memory used by this routine */
+  int nSpace;               /* Bytes of space allocated at pSpace */
+
+  pParse = pWInfo->pParse;
+  nLoop = pWInfo->nLevel;
+  WHERETRACE(0x002, ("---- begin solver.  (nRowEst=%d, nQueryLoop=%d)\n",
+                     nRowEst, pParse->nQueryLoop));
+  /* TUNING: mxChoice is the maximum number of possible paths to preserve
+  ** at each step.  Based on the number of loops in the FROM clause:
+  **
+  **     nLoop      mxChoice
+  **     -----      --------
+  **       1            1            // the most common case
+  **       2            5
+  **       3+        12 or 18        // see computeMxChoice()
+  */
+  if( nLoop<=1 ){
+    mxChoice = 1;
+  }else if( nLoop==2 ){
+    mxChoice = 5;
+  }else if( pParse->nErr ){
+    mxChoice = 1;
+  }else{
+    mxChoice = computeMxChoice(pWInfo);
+  }
+  assert( nLoop<=pWInfo->pTabList->nSrc );
+
+  /* If nRowEst is zero and there is an ORDER BY clause, ignore it. In this
+  ** case the purpose of this call is to estimate the number of rows returned
+  ** by the overall query. Once this estimate has been obtained, the caller
+  ** will invoke this function a second time, passing the estimate as the
+  ** nRowEst parameter.  */
+  if( pWInfo->pOrderBy==0 || nRowEst==0 ){
+    nOrderBy = 0;
+  }else{
+    nOrderBy = pWInfo->pOrderBy->nExpr;
+  }
+
+  /* Allocate and initialize space for aTo, aFrom and aSortCost[] */
+  nSpace = (sizeof(WherePath)+sizeof(WhereLoop*)*nLoop)*mxChoice*2;
+  nSpace += sizeof(LogEst) * nOrderBy;
+  pSpace = sqlite3StackAllocRawNN(pParse->db, nSpace);
+  if( pSpace==0 ) return SQLITE_NOMEM_BKPT;
+  aTo = (WherePath*)pSpace;
+  aFrom = aTo+mxChoice;
+  memset(aFrom, 0, sizeof(aFrom[0]));
+  pX = (WhereLoop**)(aFrom+mxChoice);
+  for(ii=mxChoice*2, pFrom=aTo; ii>0; ii--, pFrom++, pX += nLoop){
+    pFrom->aLoop = pX;
+  }
+  if( nOrderBy ){
+    /* If there is an ORDER BY clause and it is not being ignored, set up
+    ** space for the aSortCost[] array. Each element of the aSortCost array
+    ** is either zero - meaning it has not yet been initialized - or the
+    ** cost of sorting nRowEst rows of data where the first X terms of
+    ** the ORDER BY clause are already in order, where X is the array
+    ** index.  */
+    aSortCost = (LogEst*)pX;
+    memset(aSortCost, 0, sizeof(LogEst) * nOrderBy);
+  }
+  assert( aSortCost==0 || &pSpace[nSpace]==(char*)&aSortCost[nOrderBy] );
+  assert( aSortCost!=0 || &pSpace[nSpace]==(char*)pX );
+
+  /* Seed the search with a single WherePath containing zero WhereLoops.
+  **
+  ** TUNING: Do not let the number of iterations go above 28.  If the cost
+  ** of computing an automatic index is not paid back within the first 28
+  ** rows, then do not use the automatic index. */
+  aFrom[0].nRow = MIN(pParse->nQueryLoop, 48);  assert( 48==sqlite3LogEst(28) );
+  nFrom = 1;
+  assert( aFrom[0].isOrdered==0 );
+  if( nOrderBy ){
+    /* If nLoop is zero, then there are no FROM terms in the query. Since
+    ** in this case the query may return a maximum of one row, the results
+    ** are already in the requested order. Set isOrdered to nOrderBy to
+    ** indicate this. Or, if nLoop is greater than zero, set isOrdered to
+    ** -1, indicating that the result set may or may not be ordered,
+    ** depending on the loops added to the current plan.  */
+    aFrom[0].isOrdered = nLoop>0 ? -1 : nOrderBy;
+  }
+
+  /* Compute successively longer WherePaths using the previous generation
+  ** of WherePaths as the basis for the next.  Keep track of the mxChoice
+  ** best paths at each generation */
+  for(iLoop=0; iLoop<nLoop; iLoop++){
+    nTo = 0;
+    for(ii=0, pFrom=aFrom; ii<nFrom; ii++, pFrom++){
+      for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
+        LogEst nOut;                      /* Rows visited by (pFrom+pWLoop) */
+        LogEst rCost;                     /* Cost of path (pFrom+pWLoop) */
+        LogEst rUnsort;                   /* Unsorted cost of (pFrom+pWLoop) */
+        i8 isOrdered;                     /* isOrdered for (pFrom+pWLoop) */
+        Bitmask maskNew;                  /* Mask of src visited by (..) */
+        Bitmask revMask;                  /* Mask of rev-order loops for (..) */
+
+        if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
+        if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
+        if( (pWLoop->wsFlags & WHERE_AUTO_INDEX)!=0 && pFrom->nRow<3 ){
+          /* Do not use an automatic index if the this loop is expected
+          ** to run less than 1.25 times.  It is tempting to also exclude
+          ** automatic index usage on an outer loop, but sometimes an automatic
+          ** index is useful in the outer loop of a correlated subquery. */
+          assert( 10==sqlite3LogEst(2) );
+          continue;
+        }
+
+        /* At this point, pWLoop is a candidate to be the next loop.
+        ** Compute its cost */
+        rUnsort = pWLoop->rRun + pFrom->nRow;
+        if( pWLoop->rSetup ){
+          rUnsort = sqlite3LogEstAdd(pWLoop->rSetup, rUnsort);
+        }
+        rUnsort = sqlite3LogEstAdd(rUnsort, pFrom->rUnsort);
+        nOut = pFrom->nRow + pWLoop->nOut;
+        maskNew = pFrom->maskLoop | pWLoop->maskSelf;
+        isOrdered = pFrom->isOrdered;
+        if( isOrdered<0 ){
+          revMask = 0;
+          isOrdered = wherePathSatisfiesOrderBy(pWInfo,
+                       pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags,
+                       iLoop, pWLoop, &revMask);
+        }else{
+          revMask = pFrom->revLoop;
+        }
+        if( isOrdered>=0 && isOrdered<nOrderBy ){
+          if( aSortCost[isOrdered]==0 ){
+            aSortCost[isOrdered] = whereSortingCost(
+                pWInfo, nRowEst, nOrderBy, isOrdered
+            );
+          }
+          /* TUNING:  Add a small extra penalty (3) to sorting as an
+          ** extra encouragement to the query planner to select a plan
+          ** where the rows emerge in the correct order without any sorting
+          ** required. */
+          rCost = sqlite3LogEstAdd(rUnsort, aSortCost[isOrdered]) + 3;
+
+          WHERETRACE(0x002,
+              ("---- sort cost=%-3d (%d/%d) increases cost %3d to %-3d\n",
+               aSortCost[isOrdered], (nOrderBy-isOrdered), nOrderBy,
+               rUnsort, rCost));
+        }else{
+          rCost = rUnsort;
+          rUnsort -= 2;  /* TUNING:  Slight bias in favor of no-sort plans */
+        }
+
+        /* Check to see if pWLoop should be added to the set of
+        ** mxChoice best-so-far paths.
+        **
+        ** First look for an existing path among best-so-far paths
+        ** that covers the same set of loops and has the same isOrdered
+        ** setting as the current path candidate.
+        **
+        ** The term "((pTo->isOrdered^isOrdered)&0x80)==0" is equivalent
+        ** to (pTo->isOrdered==(-1))==(isOrdered==(-1))" for the range
+        ** of legal values for isOrdered, -1..64.
+        */
+        testcase( nTo==0 );
+        for(jj=0, pTo=aTo; jj<nTo; jj++, pTo++){
+          if( pTo->maskLoop==maskNew
+           && ((pTo->isOrdered^isOrdered)&0x80)==0
+          ){
+            testcase( jj==nTo-1 );
+            break;
+          }
+        }
+        if( jj>=nTo ){
+          /* None of the existing best-so-far paths match the candidate. */
+          if( nTo>=mxChoice
+           && (rCost>mxCost || (rCost==mxCost && rUnsort>=mxUnsort))
+          ){
+            /* The current candidate is no better than any of the mxChoice
+            ** paths currently in the best-so-far buffer.  So discard
+            ** this candidate as not viable. */
+#ifdef WHERETRACE_ENABLED /* 0x4 */
+            if( sqlite3WhereTrace&0x4 ){
+              sqlite3DebugPrintf("Skip   %s cost=%-3d,%3d,%3d order=%c\n",
+                  wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsort,
+                  isOrdered>=0 ? isOrdered+'0' : '?');
+            }
+#endif
+            continue;
+          }
+          /* If we reach this points it means that the new candidate path
+          ** needs to be added to the set of best-so-far paths. */
+          if( nTo<mxChoice ){
+            /* Increase the size of the aTo set by one */
+            jj = nTo++;
+          }else{
+            /* New path replaces the prior worst to keep count below mxChoice */
+            jj = mxI;
+          }
+          pTo = &aTo[jj];
+#ifdef WHERETRACE_ENABLED /* 0x4 */
+          if( sqlite3WhereTrace&0x4 ){
+            sqlite3DebugPrintf("New    %s cost=%-3d,%3d,%3d order=%c\n",
+                wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsort,
+                isOrdered>=0 ? isOrdered+'0' : '?');
+          }
+#endif
+        }else{
+          /* Control reaches here if best-so-far path pTo=aTo[jj] covers the
+          ** same set of loops and has the same isOrdered setting as the
+          ** candidate path.  Check to see if the candidate should replace
+          ** pTo or if the candidate should be skipped.
+          **
+          ** The conditional is an expanded vector comparison equivalent to:
+          **   (pTo->rCost,pTo->nRow,pTo->rUnsort) <= (rCost,nOut,rUnsort)
+          */
+          if( (pTo->rCost<rCost)
+           || (pTo->rCost==rCost && pTo->nRow<nOut)
+           || (pTo->rCost==rCost && pTo->nRow==nOut && pTo->rUnsort<rUnsort)
+           || (pTo->rCost==rCost && pTo->nRow==nOut && pTo->rUnsort==rUnsort
+                  && whereLoopIsNoBetter(pWLoop, pTo->aLoop[iLoop]) )
+          ){
+#ifdef WHERETRACE_ENABLED /* 0x4 */
+            if( sqlite3WhereTrace&0x4 ){
+              sqlite3DebugPrintf(
+                  "Skip   %s cost=%-3d,%3d,%3d order=%c",
+                  wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsort,
+                  isOrdered>=0 ? isOrdered+'0' : '?');
+              sqlite3DebugPrintf("   vs %s cost=%-3d,%3d,%3d order=%c\n",
+                  wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
+                  pTo->rUnsort, pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
+            }
+#endif
+            /* Discard the candidate path from further consideration */
+            testcase( pTo->rCost==rCost );
+            continue;
+          }
+          testcase( pTo->rCost==rCost+1 );
+          /* Control reaches here if the candidate path is better than the
+          ** pTo path.  Replace pTo with the candidate. */
+#ifdef WHERETRACE_ENABLED /* 0x4 */
+          if( sqlite3WhereTrace&0x4 ){
+            sqlite3DebugPrintf(
+                "Update %s cost=%-3d,%3d,%3d order=%c",
+                wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, rUnsort,
+                isOrdered>=0 ? isOrdered+'0' : '?');
+            sqlite3DebugPrintf("  was %s cost=%-3d,%3d,%3d order=%c\n",
+                wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
+                pTo->rUnsort, pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?');
+          }
+#endif
+        }
+        /* pWLoop is a winner.  Add it to the set of best so far */
+        pTo->maskLoop = pFrom->maskLoop | pWLoop->maskSelf;
+        pTo->revLoop = revMask;
+        pTo->nRow = nOut;
+        pTo->rCost = rCost;
+        pTo->rUnsort = rUnsort;
+        pTo->isOrdered = isOrdered;
+        memcpy(pTo->aLoop, pFrom->aLoop, sizeof(WhereLoop*)*iLoop);
+        pTo->aLoop[iLoop] = pWLoop;
+        if( nTo>=mxChoice ){
+          mxI = 0;
+          mxCost = aTo[0].rCost;
+          mxUnsort = aTo[0].nRow;
+          for(jj=1, pTo=&aTo[1]; jj<mxChoice; jj++, pTo++){
+            if( pTo->rCost>mxCost
+             || (pTo->rCost==mxCost && pTo->rUnsort>mxUnsort)
+            ){
+              mxCost = pTo->rCost;
+              mxUnsort = pTo->rUnsort;
+              mxI = jj;
+            }
+          }
+        }
+      }
+    }
+
+#ifdef WHERETRACE_ENABLED  /* >=2 */
+    if( sqlite3WhereTrace & 0x02 ){
+      LogEst rMin, rFloor = 0;
+      int nDone = 0;
+      int nProgress;
+      sqlite3DebugPrintf("---- after round %d ----\n", iLoop);
+      do{
+        nProgress = 0;
+        rMin = 0x7fff;
+        for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
+          if( pTo->rCost>rFloor && pTo->rCost<rMin ) rMin = pTo->rCost;
+        }
+        for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
+          if( pTo->rCost==rMin ){
+            sqlite3DebugPrintf(" %s cost=%-3d nrow=%-3d order=%c",
+               wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
+               pTo->isOrdered>=0 ? (pTo->isOrdered+'0') : '?');
+            if( pTo->isOrdered>0 ){
+              sqlite3DebugPrintf(" rev=0x%llx\n", pTo->revLoop);
+            }else{
+              sqlite3DebugPrintf("\n");
+            }
+            nDone++;
+            nProgress++;
+          }
+        }
+        rFloor = rMin;
+      }while( nDone<nTo && nProgress>0 );
+    }
+#endif
+
+    /* Swap the roles of aFrom and aTo for the next generation */
+    pFrom = aTo;
+    aTo = aFrom;
+    aFrom = pFrom;
+    nFrom = nTo;
+  }
+
+  if( nFrom==0 ){
+    sqlite3ErrorMsg(pParse, "no query solution");
+    sqlite3StackFreeNN(pParse->db, pSpace);
+    return SQLITE_ERROR;
+  }
+
+  /* Find the lowest cost path.  pFrom will be left pointing to that path */
+  pFrom = aFrom;
+  for(ii=1; ii<nFrom; ii++){
+    if( pFrom->rCost>aFrom[ii].rCost ) pFrom = &aFrom[ii];
+  }
+  assert( pWInfo->nLevel==nLoop );
+  /* Load the lowest cost path into pWInfo */
+  for(iLoop=0; iLoop<nLoop; iLoop++){
+    WhereLevel *pLevel = pWInfo->a + iLoop;
+    pLevel->pWLoop = pWLoop = pFrom->aLoop[iLoop];
+    pLevel->iFrom = pWLoop->iTab;
+    pLevel->iTabCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor;
+  }
+  if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0
+   && (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0
+   && pWInfo->eDistinct==WHERE_DISTINCT_NOOP
+   && nRowEst
+  ){
+    Bitmask notUsed;
+    int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pResultSet, pFrom,
+                 WHERE_DISTINCTBY, nLoop-1, pFrom->aLoop[nLoop-1], ¬Used);
+    if( rc==pWInfo->pResultSet->nExpr ){
+      pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
+    }
+  }
+  pWInfo->bOrderedInnerLoop = 0;
+  if( pWInfo->pOrderBy ){
+    pWInfo->nOBSat = pFrom->isOrdered;
+    if( pWInfo->wctrlFlags & WHERE_DISTINCTBY ){
+      if( pFrom->isOrdered==pWInfo->pOrderBy->nExpr ){
+        pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
+      }
+      /* vvv--- See check-in [12ad822d9b827777] on 2023-03-16 ---vvv */
+      assert( pWInfo->pSelect->pOrderBy==0
+           || pWInfo->nOBSat <= pWInfo->pSelect->pOrderBy->nExpr );
+    }else{
+      pWInfo->revMask = pFrom->revLoop;
+      if( pWInfo->nOBSat<=0 ){
+        pWInfo->nOBSat = 0;
+        if( nLoop>0 ){
+          u32 wsFlags = pFrom->aLoop[nLoop-1]->wsFlags;
+          if( (wsFlags & WHERE_ONEROW)==0
+           && (wsFlags&(WHERE_IPK|WHERE_COLUMN_IN))!=(WHERE_IPK|WHERE_COLUMN_IN)
+          ){
+            Bitmask m = 0;
+            int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, pFrom,
+                      WHERE_ORDERBY_LIMIT, nLoop-1, pFrom->aLoop[nLoop-1], &m);
+            testcase( wsFlags & WHERE_IPK );
+            testcase( wsFlags & WHERE_COLUMN_IN );
+            if( rc==pWInfo->pOrderBy->nExpr ){
+              pWInfo->bOrderedInnerLoop = 1;
+              pWInfo->revMask = m;
+            }
+          }
+        }
+      }else if( nLoop
+            && pWInfo->nOBSat==1
+            && (pWInfo->wctrlFlags & (WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX))!=0
+            ){
+        pWInfo->bOrderedInnerLoop = 1;
+      }
+    }
+    if( (pWInfo->wctrlFlags & WHERE_SORTBYGROUP)
+        && pWInfo->nOBSat==pWInfo->pOrderBy->nExpr && nLoop>0
+    ){
+      Bitmask revMask = 0;
+      int nOrder = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy,
+          pFrom, 0, nLoop-1, pFrom->aLoop[nLoop-1], &revMask
+      );
+      assert( pWInfo->sorted==0 );
+      if( nOrder==pWInfo->pOrderBy->nExpr ){
+        pWInfo->sorted = 1;
+        pWInfo->revMask = revMask;
+      }
+    }
+  }
+
+  pWInfo->nRowOut = pFrom->nRow;
+#ifdef WHERETRACE_ENABLED
+  pWInfo->rTotalCost = pFrom->rCost;
+#endif
+
+  /* Free temporary memory and return success */
+  sqlite3StackFreeNN(pParse->db, pSpace);
+  return SQLITE_OK;
+}
+
+/*
+** This routine implements a heuristic designed to improve query planning.
+** This routine is called in between the first and second call to
+** wherePathSolver().  Hence the name "Interstage" "Heuristic".
+**
+** The first call to wherePathSolver() (hereafter just "solver()") computes
+** the best path without regard to the order of the outputs.  The second call
+** to the solver() builds upon the first call to try to find an alternative
+** path that satisfies the ORDER BY clause.
+**
+** This routine looks at the results of the first solver() run, and for
+** every FROM clause term in the resulting query plan that uses an equality
+** constraint against an index, disable other WhereLoops for that same
+** FROM clause term that would try to do a full-table scan.  This prevents
+** an index search from being converted into a full-table scan in order to
+** satisfy an ORDER BY clause, since even though we might get slightly better
+** performance using the full-scan without sorting if the output size
+** estimates are very precise, we might also get severe performance
+** degradation using the full-scan if the output size estimate is too large.
+** It is better to err on the side of caution.
+**
+** Except, if the first solver() call generated a full-table scan in an outer
+** loop then stop this analysis at the first full-scan, since the second
+** solver() run might try to swap that full-scan for another in order to
+** get the output into the correct order.  In other words, we allow a
+** rewrite like this:
+**
+**     First Solver()                      Second Solver()
+**       |-- SCAN t1                         |-- SCAN t2
+**       |-- SEARCH t2                       `-- SEARCH t1
+**       `-- SORT USING B-TREE
+**
+** The purpose of this routine is to disallow rewrites such as:
+**
+**     First Solver()                      Second Solver()
+**       |-- SEARCH t1                       |-- SCAN t2     <--- bad!
+**       |-- SEARCH t2                       `-- SEARCH t1
+**       `-- SORT USING B-TREE
+**
+** See test cases in test/whereN.test for the real-world query that
+** originally provoked this heuristic.
+*/
+static SQLITE_NOINLINE void whereInterstageHeuristic(WhereInfo *pWInfo){
+  int i;
+#ifdef WHERETRACE_ENABLED
+  int once = 0;
+#endif
+  for(i=0; i<pWInfo->nLevel; i++){
+    WhereLoop *p = pWInfo->a[i].pWLoop;
+    if( p==0 ) break;
+    if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 ) continue;
+    if( (p->wsFlags & (WHERE_COLUMN_EQ|WHERE_COLUMN_NULL|WHERE_COLUMN_IN))!=0 ){
+      u8 iTab = p->iTab;
+      WhereLoop *pLoop;
+      for(pLoop=pWInfo->pLoops; pLoop; pLoop=pLoop->pNextLoop){
+        if( pLoop->iTab!=iTab ) continue;
+        if( (pLoop->wsFlags & (WHERE_CONSTRAINT|WHERE_AUTO_INDEX))!=0 ){
+          /* Auto-index and index-constrained loops allowed to remain */
+          continue;
+        }
+#ifdef WHERETRACE_ENABLED
+        if( sqlite3WhereTrace & 0x80 ){
+          if( once==0 ){
+            sqlite3DebugPrintf("Loops disabled by interstage heuristic:\n");
+            once = 1;
+          }
+          sqlite3WhereLoopPrint(pLoop, &pWInfo->sWC);
+        }
+#endif /* WHERETRACE_ENABLED */
+        pLoop->prereq = ALLBITS;  /* Prevent 2nd solver() from using this one */
+      }
+    }else{
+      break;
+    }
+  }
+}
+
+/*
+** Most queries use only a single table (they are not joins) and have
+** simple == constraints against indexed fields.  This routine attempts
+** to plan those simple cases using much less ceremony than the
+** general-purpose query planner, and thereby yield faster sqlite3_prepare()
+** times for the common case.
+**
+** Return non-zero on success, if this query can be handled by this
+** no-frills query planner.  Return zero if this query needs the
+** general-purpose query planner.
+*/
+static int whereShortCut(WhereLoopBuilder *pBuilder){
+  WhereInfo *pWInfo;
+  SrcItem *pItem;
+  WhereClause *pWC;
+  WhereTerm *pTerm;
+  WhereLoop *pLoop;
+  int iCur;
+  int j;
+  Table *pTab;
+  Index *pIdx;
+  WhereScan scan;
+
+  pWInfo = pBuilder->pWInfo;
+  if( pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE ) return 0;
+  assert( pWInfo->pTabList->nSrc>=1 );
+  pItem = pWInfo->pTabList->a;
+  pTab = pItem->pSTab;
+  if( IsVirtual(pTab) ) return 0;
+  if( pItem->fg.isIndexedBy || pItem->fg.notIndexed ){
+    testcase( pItem->fg.isIndexedBy );
+    testcase( pItem->fg.notIndexed );
+    return 0;
+  }
+  iCur = pItem->iCursor;
+  pWC = &pWInfo->sWC;
+  pLoop = pBuilder->pNew;
+  pLoop->wsFlags = 0;
+  pLoop->nSkip = 0;
+  pTerm = whereScanInit(&scan, pWC, iCur, -1, WO_EQ|WO_IS, 0);
+  while( pTerm && pTerm->prereqRight ) pTerm = whereScanNext(&scan);
+  if( pTerm ){
+    testcase( pTerm->eOperator & WO_IS );
+    pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW;
+    pLoop->aLTerm[0] = pTerm;
+    pLoop->nLTerm = 1;
+    pLoop->u.btree.nEq = 1;
+    /* TUNING: Cost of a rowid lookup is 10 */
+    pLoop->rRun = 33;  /* 33==sqlite3LogEst(10) */
+  }else{
+    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+      int opMask;
+      assert( pLoop->aLTermSpace==pLoop->aLTerm );
+      if( !IsUniqueIndex(pIdx)
+       || pIdx->pPartIdxWhere!=0
+       || pIdx->nKeyCol>ArraySize(pLoop->aLTermSpace)
+      ) continue;
+      opMask = pIdx->uniqNotNull ? (WO_EQ|WO_IS) : WO_EQ;
+      for(j=0; j<pIdx->nKeyCol; j++){
+        pTerm = whereScanInit(&scan, pWC, iCur, j, opMask, pIdx);
+        while( pTerm && pTerm->prereqRight ) pTerm = whereScanNext(&scan);
+        if( pTerm==0 ) break;
+        testcase( pTerm->eOperator & WO_IS );
+        pLoop->aLTerm[j] = pTerm;
+      }
+      if( j!=pIdx->nKeyCol ) continue;
+      pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_ONEROW|WHERE_INDEXED;
+      if( pIdx->isCovering || (pItem->colUsed & pIdx->colNotIdxed)==0 ){
+        pLoop->wsFlags |= WHERE_IDX_ONLY;
+      }
+      pLoop->nLTerm = j;
+      pLoop->u.btree.nEq = j;
+      pLoop->u.btree.pIndex = pIdx;
+      /* TUNING: Cost of a unique index lookup is 15 */
+      pLoop->rRun = 39;  /* 39==sqlite3LogEst(15) */
+      break;
+    }
+  }
+  if( pLoop->wsFlags ){
+    pLoop->nOut = (LogEst)1;
+    pWInfo->a[0].pWLoop = pLoop;
+    assert( pWInfo->sMaskSet.n==1 && iCur==pWInfo->sMaskSet.ix[0] );
+    pLoop->maskSelf = 1; /* sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur); */
+    pWInfo->a[0].iTabCur = iCur;
+    pWInfo->nRowOut = 1;
+    if( pWInfo->pOrderBy ) pWInfo->nOBSat =  pWInfo->pOrderBy->nExpr;
+    if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
+      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+    }
+    if( scan.iEquiv>1 ) pLoop->wsFlags |= WHERE_TRANSCONS;
+#ifdef SQLITE_DEBUG
+    pLoop->cId = '0';
+#endif
+#ifdef WHERETRACE_ENABLED
+    if( sqlite3WhereTrace & 0x02 ){
+      sqlite3DebugPrintf("whereShortCut() used to compute solution\n");
+    }
+#endif
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Helper function for exprIsDeterministic().
+*/
+static int exprNodeIsDeterministic(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_FUNCTION && ExprHasProperty(pExpr, EP_ConstFunc)==0 ){
+    pWalker->eCode = 0;
+    return WRC_Abort;
+  }
+  return WRC_Continue;
+}
+
+/*
+** Return true if the expression contains no non-deterministic SQL
+** functions. Do not consider non-deterministic SQL functions that are
+** part of sub-select statements.
+*/
+static int exprIsDeterministic(Expr *p){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.eCode = 1;
+  w.xExprCallback = exprNodeIsDeterministic;
+  w.xSelectCallback = sqlite3SelectWalkFail;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode;
+}
+
+
+#ifdef WHERETRACE_ENABLED
+/*
+** Display all WhereLoops in pWInfo
+*/
+static void showAllWhereLoops(WhereInfo *pWInfo, WhereClause *pWC){
+  if( sqlite3WhereTrace ){    /* Display all of the WhereLoop objects */
+    WhereLoop *p;
+    int i;
+    static const char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz"
+                                           "ABCDEFGHIJKLMNOPQRSTUVWYXZ";
+    for(p=pWInfo->pLoops, i=0; p; p=p->pNextLoop, i++){
+      p->cId = zLabel[i%(sizeof(zLabel)-1)];
+      sqlite3WhereLoopPrint(p, pWC);
+    }
+  }
+}
+# define WHERETRACE_ALL_LOOPS(W,C) showAllWhereLoops(W,C)
+#else
+# define WHERETRACE_ALL_LOOPS(W,C)
+#endif
+
+/* Attempt to omit tables from a join that do not affect the result.
+** For a table to not affect the result, the following must be true:
+**
+**   1) The query must not be an aggregate.
+**   2) The table must be the RHS of a LEFT JOIN.
+**   3) Either the query must be DISTINCT, or else the ON or USING clause
+**      must contain a constraint that limits the scan of the table to
+**      at most a single row.
+**   4) The table must not be referenced by any part of the query apart
+**      from its own USING or ON clause.
+**   5) The table must not have an inner-join ON or USING clause if there is
+**      a RIGHT JOIN anywhere in the query.  Otherwise the ON/USING clause
+**      might move from the right side to the left side of the RIGHT JOIN.
+**      Note: Due to (2), this condition can only arise if the table is
+**      the right-most table of a subquery that was flattened into the
+**      main query and that subquery was the right-hand operand of an
+**      inner join that held an ON or USING clause.
+**   6) The ORDER BY clause has 63 or fewer terms
+**   7) The omit-noop-join optimization is enabled.
+**
+** Items (1), (6), and (7) are checked by the caller.
+**
+** For example, given:
+**
+**     CREATE TABLE t1(ipk INTEGER PRIMARY KEY, v1);
+**     CREATE TABLE t2(ipk INTEGER PRIMARY KEY, v2);
+**     CREATE TABLE t3(ipk INTEGER PRIMARY KEY, v3);
+**
+** then table t2 can be omitted from the following:
+**
+**     SELECT v1, v3 FROM t1
+**       LEFT JOIN t2 ON (t1.ipk=t2.ipk)
+**       LEFT JOIN t3 ON (t1.ipk=t3.ipk)
+**
+** or from:
+**
+**     SELECT DISTINCT v1, v3 FROM t1
+**       LEFT JOIN t2
+**       LEFT JOIN t3 ON (t1.ipk=t3.ipk)
+*/
+static SQLITE_NOINLINE Bitmask whereOmitNoopJoin(
+  WhereInfo *pWInfo,
+  Bitmask notReady
+){
+  int i;
+  Bitmask tabUsed;
+  int hasRightJoin;
+
+  /* Preconditions checked by the caller */
+  assert( pWInfo->nLevel>=2 );
+  assert( OptimizationEnabled(pWInfo->pParse->db, SQLITE_OmitNoopJoin) );
+
+  /* These two preconditions checked by the caller combine to guarantee
+  ** condition (1) of the header comment */
+  assert( pWInfo->pResultSet!=0 );
+  assert( 0==(pWInfo->wctrlFlags & WHERE_AGG_DISTINCT) );
+
+  tabUsed = sqlite3WhereExprListUsage(&pWInfo->sMaskSet, pWInfo->pResultSet);
+  if( pWInfo->pOrderBy ){
+    tabUsed |= sqlite3WhereExprListUsage(&pWInfo->sMaskSet, pWInfo->pOrderBy);
+  }
+  hasRightJoin = (pWInfo->pTabList->a[0].fg.jointype & JT_LTORJ)!=0;
+  for(i=pWInfo->nLevel-1; i>=1; i--){
+    WhereTerm *pTerm, *pEnd;
+    SrcItem *pItem;
+    WhereLoop *pLoop;
+    Bitmask m1;
+    pLoop = pWInfo->a[i].pWLoop;
+    pItem = &pWInfo->pTabList->a[pLoop->iTab];
+    if( (pItem->fg.jointype & (JT_LEFT|JT_RIGHT))!=JT_LEFT ) continue;
+    if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)==0
+     && (pLoop->wsFlags & WHERE_ONEROW)==0
+    ){
+      continue;
+    }
+    if( (tabUsed & pLoop->maskSelf)!=0 ) continue;
+    pEnd = pWInfo->sWC.a + pWInfo->sWC.nTerm;
+    for(pTerm=pWInfo->sWC.a; pTerm<pEnd; pTerm++){
+      if( (pTerm->prereqAll & pLoop->maskSelf)!=0 ){
+        if( !ExprHasProperty(pTerm->pExpr, EP_OuterON)
+         || pTerm->pExpr->w.iJoin!=pItem->iCursor
+        ){
+          break;
+        }
+      }
+      if( hasRightJoin
+       && ExprHasProperty(pTerm->pExpr, EP_InnerON)
+       && NEVER(pTerm->pExpr->w.iJoin==pItem->iCursor)
+      ){
+        break;  /* restriction (5) */
+      }
+    }
+    if( pTerm<pEnd ) continue;
+    WHERETRACE(0xffffffff,("-> omit unused FROM-clause term %c\n",pLoop->cId));
+    m1 = MASKBIT(i)-1;
+    testcase( ((pWInfo->revMask>>1) & ~m1)!=0 );
+    pWInfo->revMask = (m1 & pWInfo->revMask) | ((pWInfo->revMask>>1) & ~m1);
+    notReady &= ~pLoop->maskSelf;
+    for(pTerm=pWInfo->sWC.a; pTerm<pEnd; pTerm++){
+      if( (pTerm->prereqAll & pLoop->maskSelf)!=0 ){
+        pTerm->wtFlags |= TERM_CODED;
+      }
+    }
+    if( i!=pWInfo->nLevel-1 ){
+      int nByte = (pWInfo->nLevel-1-i) * sizeof(WhereLevel);
+      memmove(&pWInfo->a[i], &pWInfo->a[i+1], nByte);
+    }
+    pWInfo->nLevel--;
+    assert( pWInfo->nLevel>0 );
+  }
+  return notReady;
+}
+
+/*
+** Check to see if there are any SEARCH loops that might benefit from
+** using a Bloom filter.  Consider a Bloom filter if:
+**
+**   (1)  The SEARCH happens more than N times where N is the number
+**        of rows in the table that is being considered for the Bloom
+**        filter.
+**   (2)  Some searches are expected to find zero rows.  (This is determined
+**        by the WHERE_SELFCULL flag on the term.)
+**   (3)  Bloom-filter processing is not disabled.  (Checked by the
+**        caller.)
+**   (4)  The size of the table being searched is known by ANALYZE.
+**
+** This block of code merely checks to see if a Bloom filter would be
+** appropriate, and if so sets the WHERE_BLOOMFILTER flag on the
+** WhereLoop.  The implementation of the Bloom filter comes further
+** down where the code for each WhereLoop is generated.
+*/
+static SQLITE_NOINLINE void whereCheckIfBloomFilterIsUseful(
+  const WhereInfo *pWInfo
+){
+  int i;
+  LogEst nSearch = 0;
+
+  assert( pWInfo->nLevel>=2 );
+  assert( OptimizationEnabled(pWInfo->pParse->db, SQLITE_BloomFilter) );
+  for(i=0; i<pWInfo->nLevel; i++){
+    WhereLoop *pLoop = pWInfo->a[i].pWLoop;
+    const unsigned int reqFlags = (WHERE_SELFCULL|WHERE_COLUMN_EQ);
+    SrcItem *pItem = &pWInfo->pTabList->a[pLoop->iTab];
+    Table *pTab = pItem->pSTab;
+    if( (pTab->tabFlags & TF_HasStat1)==0 ) break;
+    pTab->tabFlags |= TF_MaybeReanalyze;
+    if( i>=1
+     && (pLoop->wsFlags & reqFlags)==reqFlags
+     /* vvvvvv--- Always the case if WHERE_COLUMN_EQ is defined */
+     && ALWAYS((pLoop->wsFlags & (WHERE_IPK|WHERE_INDEXED))!=0)
+    ){
+      if( nSearch > pTab->nRowLogEst ){
+        testcase( pItem->fg.jointype & JT_LEFT );
+        pLoop->wsFlags |= WHERE_BLOOMFILTER;
+        pLoop->wsFlags &= ~WHERE_IDX_ONLY;
+        WHERETRACE(0xffffffff, (
+           "-> use Bloom-filter on loop %c because there are ~%.1e "
+           "lookups into %s which has only ~%.1e rows\n",
+           pLoop->cId, (double)sqlite3LogEstToInt(nSearch), pTab->zName,
+           (double)sqlite3LogEstToInt(pTab->nRowLogEst)));
+      }
+    }
+    nSearch += pLoop->nOut;
+  }
+}
+
+/*
+** The index pIdx is used by a query and contains one or more expressions.
+** In other words pIdx is an index on an expression.  iIdxCur is the cursor
+** number for the index and iDataCur is the cursor number for the corresponding
+** table.
+**
+** This routine adds IndexedExpr entries to the Parse->pIdxEpr field for
+** each of the expressions in the index so that the expression code generator
+** will know to replace occurrences of the indexed expression with
+** references to the corresponding column of the index.
+*/
+static SQLITE_NOINLINE void whereAddIndexedExpr(
+  Parse *pParse,     /* Add IndexedExpr entries to pParse->pIdxEpr */
+  Index *pIdx,       /* The index-on-expression that contains the expressions */
+  int iIdxCur,       /* Cursor number for pIdx */
+  SrcItem *pTabItem  /* The FROM clause entry for the table */
+){
+  int i;
+  IndexedExpr *p;
+  Table *pTab;
+  assert( pIdx->bHasExpr );
+  pTab = pIdx->pTable;
+  for(i=0; i<pIdx->nColumn; i++){
+    Expr *pExpr;
+    int j = pIdx->aiColumn[i];
+    if( j==XN_EXPR ){
+      pExpr = pIdx->aColExpr->a[i].pExpr;
+    }else if( j>=0 && (pTab->aCol[j].colFlags & COLFLAG_VIRTUAL)!=0 ){
+      pExpr = sqlite3ColumnExpr(pTab, &pTab->aCol[j]);
+    }else{
+      continue;
+    }
+    if( sqlite3ExprIsConstant(0,pExpr) ) continue;
+    p = sqlite3DbMallocRaw(pParse->db,  sizeof(IndexedExpr));
+    if( p==0 ) break;
+    p->pIENext = pParse->pIdxEpr;
+#ifdef WHERETRACE_ENABLED
+    if( sqlite3WhereTrace & 0x200 ){
+      sqlite3DebugPrintf("New pParse->pIdxEpr term {%d,%d}\n", iIdxCur, i);
+      if( sqlite3WhereTrace & 0x5000 ) sqlite3ShowExpr(pExpr);
+    }
+#endif
+    p->pExpr = sqlite3ExprDup(pParse->db, pExpr, 0);
+    p->iDataCur = pTabItem->iCursor;
+    p->iIdxCur = iIdxCur;
+    p->iIdxCol = i;
+    p->bMaybeNullRow = (pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0;
+    if( sqlite3IndexAffinityStr(pParse->db, pIdx) ){
+      p->aff = pIdx->zColAff[i];
+    }
+#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
+    p->zIdxName = pIdx->zName;
+#endif
+    pParse->pIdxEpr = p;
+    if( p->pIENext==0 ){
+      void *pArg = (void*)&pParse->pIdxEpr;
+      sqlite3ParserAddCleanup(pParse, whereIndexedExprCleanup, pArg);
+    }
+  }
+}
+
+/*
+** Set the reverse-scan order mask to one for all tables in the query
+** with the exception of MATERIALIZED common table expressions that have
+** their own internal ORDER BY clauses.
+**
+** This implements the PRAGMA reverse_unordered_selects=ON setting.
+** (Also SQLITE_DBCONFIG_REVERSE_SCANORDER).
+*/
+static SQLITE_NOINLINE void whereReverseScanOrder(WhereInfo *pWInfo){
+  int ii;
+  for(ii=0; ii<pWInfo->pTabList->nSrc; ii++){
+    SrcItem *pItem = &pWInfo->pTabList->a[ii];
+    if( !pItem->fg.isCte
+     || pItem->u2.pCteUse->eM10d!=M10d_Yes
+     || NEVER(pItem->fg.isSubquery==0)
+     || pItem->u4.pSubq->pSelect->pOrderBy==0
+    ){
+      pWInfo->revMask |= MASKBIT(ii);
+    }
+  }
+}
+
+/*
+** Generate the beginning of the loop used for WHERE clause processing.
+** The return value is a pointer to an opaque structure that contains
+** information needed to terminate the loop.  Later, the calling routine
+** should invoke sqlite3WhereEnd() with the return value of this function
+** in order to complete the WHERE clause processing.
+**
+** If an error occurs, this routine returns NULL.
+**
+** The basic idea is to do a nested loop, one loop for each table in
+** the FROM clause of a select.  (INSERT and UPDATE statements are the
+** same as a SELECT with only a single table in the FROM clause.)  For
+** example, if the SQL is this:
+**
+**       SELECT * FROM t1, t2, t3 WHERE ...;
+**
+** Then the code generated is conceptually like the following:
+**
+**      foreach row1 in t1 do       \    Code generated
+**        foreach row2 in t2 do      |-- by sqlite3WhereBegin()
+**          foreach row3 in t3 do   /
+**            ...
+**          end                     \    Code generated
+**        end                        |-- by sqlite3WhereEnd()
+**      end                         /
+**
+** Note that the loops might not be nested in the order in which they
+** appear in the FROM clause if a different order is better able to make
+** use of indices.  Note also that when the IN operator appears in
+** the WHERE clause, it might result in additional nested loops for
+** scanning through all values on the right-hand side of the IN.
+**
+** There are Btree cursors associated with each table.  t1 uses cursor
+** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
+** And so forth.  This routine generates code to open those VDBE cursors
+** and sqlite3WhereEnd() generates the code to close them.
+**
+** The code that sqlite3WhereBegin() generates leaves the cursors named
+** in pTabList pointing at their appropriate entries.  The [...] code
+** can use OP_Column and OP_Rowid opcodes on these cursors to extract
+** data from the various tables of the loop.
+**
+** If the WHERE clause is empty, the foreach loops must each scan their
+** entire tables.  Thus a three-way join is an O(N^3) operation.  But if
+** the tables have indices and there are terms in the WHERE clause that
+** refer to those indices, a complete table scan can be avoided and the
+** code will run much faster.  Most of the work of this routine is checking
+** to see if there are indices that can be used to speed up the loop.
+**
+** Terms of the WHERE clause are also used to limit which rows actually
+** make it to the "..." in the middle of the loop.  After each "foreach",
+** terms of the WHERE clause that use only terms in that loop and outer
+** loops are evaluated and if false a jump is made around all subsequent
+** inner loops (or around the "..." if the test occurs within the inner-
+** most loop)
+**
+** OUTER JOINS
+**
+** An outer join of tables t1 and t2 is conceptually coded as follows:
+**
+**    foreach row1 in t1 do
+**      flag = 0
+**      foreach row2 in t2 do
+**        start:
+**          ...
+**          flag = 1
+**      end
+**      if flag==0 then
+**        move the row2 cursor to a null row
+**        goto start
+**      fi
+**    end
+**
+** ORDER BY CLAUSE PROCESSING
+**
+** pOrderBy is a pointer to the ORDER BY clause (or the GROUP BY clause
+** if the WHERE_GROUPBY flag is set in wctrlFlags) of a SELECT statement
+** if there is one.  If there is no ORDER BY clause or if this routine
+** is called from an UPDATE or DELETE statement, then pOrderBy is NULL.
+**
+** The iIdxCur parameter is the cursor number of an index.  If
+** WHERE_OR_SUBCLAUSE is set, iIdxCur is the cursor number of an index
+** to use for OR clause processing.  The WHERE clause should use this
+** specific cursor.  If WHERE_ONEPASS_DESIRED is set, then iIdxCur is
+** the first cursor in an array of cursors for all indices.  iIdxCur should
+** be used to compute the appropriate cursor depending on which index is
+** used.
+*/
+SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
+  Parse *pParse,          /* The parser context */
+  SrcList *pTabList,      /* FROM clause: A list of all tables to be scanned */
+  Expr *pWhere,           /* The WHERE clause */
+  ExprList *pOrderBy,     /* An ORDER BY (or GROUP BY) clause, or NULL */
+  ExprList *pResultSet,   /* Query result set.  Req'd for DISTINCT */
+  Select *pSelect,        /* The entire SELECT statement */
+  u16 wctrlFlags,         /* The WHERE_* flags defined in sqliteInt.h */
+  int iAuxArg             /* If WHERE_OR_SUBCLAUSE is set, index cursor number
+                          ** If WHERE_USE_LIMIT, then the limit amount */
+){
+  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
+  int nTabList;              /* Number of elements in pTabList */
+  WhereInfo *pWInfo;         /* Will become the return value of this function */
+  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
+  Bitmask notReady;          /* Cursors that are not yet positioned */
+  WhereLoopBuilder sWLB;     /* The WhereLoop builder */
+  WhereMaskSet *pMaskSet;    /* The expression mask set */
+  WhereLevel *pLevel;        /* A single level in pWInfo->a[] */
+  WhereLoop *pLoop;          /* Pointer to a single WhereLoop object */
+  int ii;                    /* Loop counter */
+  sqlite3 *db;               /* Database connection */
+  int rc;                    /* Return code */
+  u8 bFordelete = 0;         /* OPFLAG_FORDELETE or zero, as appropriate */
+
+  assert( (wctrlFlags & WHERE_ONEPASS_MULTIROW)==0 || (
+        (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0
+     && (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
+  ));
+
+  /* Only one of WHERE_OR_SUBCLAUSE or WHERE_USE_LIMIT */
+  assert( (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
+            || (wctrlFlags & WHERE_USE_LIMIT)==0 );
+
+  /* Variable initialization */
+  db = pParse->db;
+  memset(&sWLB, 0, sizeof(sWLB));
+
+  /* An ORDER/GROUP BY clause of more than 63 terms cannot be optimized */
+  testcase( pOrderBy && pOrderBy->nExpr==BMS-1 );
+  if( pOrderBy && pOrderBy->nExpr>=BMS ){
+    pOrderBy = 0;
+    wctrlFlags &= ~WHERE_WANT_DISTINCT;
+    wctrlFlags |= WHERE_KEEP_ALL_JOINS; /* Disable omit-noop-join opt */
+  }
+
+  /* The number of tables in the FROM clause is limited by the number of
+  ** bits in a Bitmask
+  */
+  testcase( pTabList->nSrc==BMS );
+  if( pTabList->nSrc>BMS ){
+    sqlite3ErrorMsg(pParse, "at most %d tables in a join", BMS);
+    return 0;
+  }
+
+  /* This function normally generates a nested loop for all tables in
+  ** pTabList.  But if the WHERE_OR_SUBCLAUSE flag is set, then we should
+  ** only generate code for the first table in pTabList and assume that
+  ** any cursors associated with subsequent tables are uninitialized.
+  */
+  nTabList = (wctrlFlags & WHERE_OR_SUBCLAUSE) ? 1 : pTabList->nSrc;
+
+  /* Allocate and initialize the WhereInfo structure that will become the
+  ** return value. A single allocation is used to store the WhereInfo
+  ** struct, the contents of WhereInfo.a[], the WhereClause structure
+  ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
+  ** field (type Bitmask) it must be aligned on an 8-byte boundary on
+  ** some architectures. Hence the ROUND8() below.
+  */
+  nByteWInfo = ROUND8P(sizeof(WhereInfo));
+  if( nTabList>1 ){
+    nByteWInfo = ROUND8P(nByteWInfo + (nTabList-1)*sizeof(WhereLevel));
+  }
+  pWInfo = sqlite3DbMallocRawNN(db, nByteWInfo + sizeof(WhereLoop));
+  if( db->mallocFailed ){
+    sqlite3DbFree(db, pWInfo);
+    pWInfo = 0;
+    goto whereBeginError;
+  }
+  pWInfo->pParse = pParse;
+  pWInfo->pTabList = pTabList;
+  pWInfo->pOrderBy = pOrderBy;
+#if WHERETRACE_ENABLED
+  pWInfo->pWhere = pWhere;
+#endif
+  pWInfo->pResultSet = pResultSet;
+  pWInfo->aiCurOnePass[0] = pWInfo->aiCurOnePass[1] = -1;
+  pWInfo->nLevel = nTabList;
+  pWInfo->iBreak = pWInfo->iContinue = sqlite3VdbeMakeLabel(pParse);
+  pWInfo->wctrlFlags = wctrlFlags;
+  pWInfo->iLimit = iAuxArg;
+  pWInfo->savedNQueryLoop = pParse->nQueryLoop;
+  pWInfo->pSelect = pSelect;
+  memset(&pWInfo->nOBSat, 0,
+         offsetof(WhereInfo,sWC) - offsetof(WhereInfo,nOBSat));
+  memset(&pWInfo->a[0], 0, sizeof(WhereLoop)+nTabList*sizeof(WhereLevel));
+  assert( pWInfo->eOnePass==ONEPASS_OFF );  /* ONEPASS defaults to OFF */
+  pMaskSet = &pWInfo->sMaskSet;
+  pMaskSet->n = 0;
+  pMaskSet->ix[0] = -99; /* Initialize ix[0] to a value that can never be
+                         ** a valid cursor number, to avoid an initial
+                         ** test for pMaskSet->n==0 in sqlite3WhereGetMask() */
+  sWLB.pWInfo = pWInfo;
+  sWLB.pWC = &pWInfo->sWC;
+  sWLB.pNew = (WhereLoop*)(((char*)pWInfo)+nByteWInfo);
+  assert( EIGHT_BYTE_ALIGNMENT(sWLB.pNew) );
+  whereLoopInit(sWLB.pNew);
+#ifdef SQLITE_DEBUG
+  sWLB.pNew->cId = '*';
+#endif
+
+  /* Split the WHERE clause into separate subexpressions where each
+  ** subexpression is separated by an AND operator.
+  */
+  sqlite3WhereClauseInit(&pWInfo->sWC, pWInfo);
+  sqlite3WhereSplit(&pWInfo->sWC, pWhere, TK_AND);
+
+  /* Special case: No FROM clause
+  */
+  if( nTabList==0 ){
+    if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr;
+    if( (wctrlFlags & WHERE_WANT_DISTINCT)!=0
+     && OptimizationEnabled(db, SQLITE_DistinctOpt)
+    ){
+      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+    }
+    if( ALWAYS(pWInfo->pSelect)
+     && (pWInfo->pSelect->selFlags & SF_MultiValue)==0
+    ){
+      ExplainQueryPlan((pParse, 0, "SCAN CONSTANT ROW"));
+    }
+  }else{
+    /* Assign a bit from the bitmask to every term in the FROM clause.
+    **
+    ** The N-th term of the FROM clause is assigned a bitmask of 1<<N.
+    **
+    ** The rule of the previous sentence ensures that if X is the bitmask for
+    ** a table T, then X-1 is the bitmask for all other tables to the left of T.
+    ** Knowing the bitmask for all tables to the left of a left join is
+    ** important.  Ticket #3015.
+    **
+    ** Note that bitmasks are created for all pTabList->nSrc tables in
+    ** pTabList, not just the first nTabList tables.  nTabList is normally
+    ** equal to pTabList->nSrc but might be shortened to 1 if the
+    ** WHERE_OR_SUBCLAUSE flag is set.
+    */
+    ii = 0;
+    do{
+      createMask(pMaskSet, pTabList->a[ii].iCursor);
+      sqlite3WhereTabFuncArgs(pParse, &pTabList->a[ii], &pWInfo->sWC);
+    }while( (++ii)<pTabList->nSrc );
+  #ifdef SQLITE_DEBUG
+    {
+      Bitmask mx = 0;
+      for(ii=0; ii<pTabList->nSrc; ii++){
+        Bitmask m = sqlite3WhereGetMask(pMaskSet, pTabList->a[ii].iCursor);
+        assert( m>=mx );
+        mx = m;
+      }
+    }
+  #endif
+  }
+
+  /* Analyze all of the subexpressions. */
+  sqlite3WhereExprAnalyze(pTabList, &pWInfo->sWC);
+  if( pSelect && pSelect->pLimit ){
+    sqlite3WhereAddLimit(&pWInfo->sWC, pSelect);
+  }
+  if( pParse->nErr ) goto whereBeginError;
+
+  /* The False-WHERE-Term-Bypass optimization:
+  **
+  ** If there are WHERE terms that are false, then no rows will be output,
+  ** so skip over all of the code generated here.
+  **
+  ** Conditions:
+  **
+  **   (1)  The WHERE term must not refer to any tables in the join.
+  **   (2)  The term must not come from an ON clause on the
+  **        right-hand side of a LEFT or FULL JOIN.
+  **   (3)  The term must not come from an ON clause, or there must be
+  **        no RIGHT or FULL OUTER joins in pTabList.
+  **   (4)  If the expression contains non-deterministic functions
+  **        that are not within a sub-select. This is not required
+  **        for correctness but rather to preserves SQLite's legacy
+  **        behaviour in the following two cases:
+  **
+  **          WHERE random()>0;           -- eval random() once per row
+  **          WHERE (SELECT random())>0;  -- eval random() just once overall
+  **
+  ** Note that the Where term need not be a constant in order for this
+  ** optimization to apply, though it does need to be constant relative to
+  ** the current subquery (condition 1).  The term might include variables
+  ** from outer queries so that the value of the term changes from one
+  ** invocation of the current subquery to the next.
+  */
+  for(ii=0; ii<sWLB.pWC->nBase; ii++){
+    WhereTerm *pT = &sWLB.pWC->a[ii];  /* A term of the WHERE clause */
+    Expr *pX;                          /* The expression of pT */
+    if( pT->wtFlags & TERM_VIRTUAL ) continue;
+    pX = pT->pExpr;
+    assert( pX!=0 );
+    assert( pT->prereqAll!=0 || !ExprHasProperty(pX, EP_OuterON) );
+    if( pT->prereqAll==0                           /* Conditions (1) and (2) */
+     && (nTabList==0 || exprIsDeterministic(pX))   /* Condition (4) */
+     && !(ExprHasProperty(pX, EP_InnerON)          /* Condition (3) */
+          && (pTabList->a[0].fg.jointype & JT_LTORJ)!=0 )
+    ){
+      sqlite3ExprIfFalse(pParse, pX, pWInfo->iBreak, SQLITE_JUMPIFNULL);
+      pT->wtFlags |= TERM_CODED;
+    }
+  }
+
+  if( wctrlFlags & WHERE_WANT_DISTINCT ){
+    if( OptimizationDisabled(db, SQLITE_DistinctOpt) ){
+      /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via
+      ** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */
+      wctrlFlags &= ~WHERE_WANT_DISTINCT;
+      pWInfo->wctrlFlags &= ~WHERE_WANT_DISTINCT;
+    }else if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
+      /* The DISTINCT marking is pointless.  Ignore it. */
+      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
+    }else if( pOrderBy==0 ){
+      /* Try to ORDER BY the result set to make distinct processing easier */
+      pWInfo->wctrlFlags |= WHERE_DISTINCTBY;
+      pWInfo->pOrderBy = pResultSet;
+    }
+  }
+
+  /* Construct the WhereLoop objects */
+#if defined(WHERETRACE_ENABLED)
+  if( sqlite3WhereTrace & 0xffffffff ){
+    sqlite3DebugPrintf("*** Optimizer Start *** (wctrlFlags: 0x%x",wctrlFlags);
+    if( wctrlFlags & WHERE_USE_LIMIT ){
+      sqlite3DebugPrintf(", limit: %d", iAuxArg);
+    }
+    sqlite3DebugPrintf(")\n");
+    if( sqlite3WhereTrace & 0x8000 ){
+      Select sSelect;
+      memset(&sSelect, 0, sizeof(sSelect));
+      sSelect.selFlags = SF_WhereBegin;
+      sSelect.pSrc = pTabList;
+      sSelect.pWhere = pWhere;
+      sSelect.pOrderBy = pOrderBy;
+      sSelect.pEList = pResultSet;
+      sqlite3TreeViewSelect(0, &sSelect, 0);
+    }
+    if( sqlite3WhereTrace & 0x4000 ){ /* Display all WHERE clause terms */
+      sqlite3DebugPrintf("---- WHERE clause at start of analysis:\n");
+      sqlite3WhereClausePrint(sWLB.pWC);
+    }
+  }
+#endif
+
+  if( nTabList!=1 || whereShortCut(&sWLB)==0 ){
+    rc = whereLoopAddAll(&sWLB);
+    if( rc ) goto whereBeginError;
+
+#ifdef SQLITE_ENABLE_STAT4
+    /* If one or more WhereTerm.truthProb values were used in estimating
+    ** loop parameters, but then those truthProb values were subsequently
+    ** changed based on STAT4 information while computing subsequent loops,
+    ** then we need to rerun the whole loop building process so that all
+    ** loops will be built using the revised truthProb values. */
+    if( sWLB.bldFlags2 & SQLITE_BLDF2_2NDPASS ){
+      WHERETRACE_ALL_LOOPS(pWInfo, sWLB.pWC);
+      WHERETRACE(0xffffffff,
+           ("**** Redo all loop computations due to"
+            " TERM_HIGHTRUTH changes ****\n"));
+      while( pWInfo->pLoops ){
+        WhereLoop *p = pWInfo->pLoops;
+        pWInfo->pLoops = p->pNextLoop;
+        whereLoopDelete(db, p);
+      }
+      rc = whereLoopAddAll(&sWLB);
+      if( rc ) goto whereBeginError;
+    }
+#endif
+    WHERETRACE_ALL_LOOPS(pWInfo, sWLB.pWC);
+
+    wherePathSolver(pWInfo, 0);
+    if( db->mallocFailed ) goto whereBeginError;
+    if( pWInfo->pOrderBy ){
+       whereInterstageHeuristic(pWInfo);
+       wherePathSolver(pWInfo, pWInfo->nRowOut<0 ? 1 : pWInfo->nRowOut+1);
+       if( db->mallocFailed ) goto whereBeginError;
+    }
+
+    /* TUNING:  Assume that a DISTINCT clause on a subquery reduces
+    ** the output size by a factor of 8 (LogEst -30).
+    */
+    if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0 ){
+      WHERETRACE(0x0080,("nRowOut reduced from %d to %d due to DISTINCT\n",
+                         pWInfo->nRowOut, pWInfo->nRowOut-30));
+      pWInfo->nRowOut -= 30;
+    }
+
+  }
+  assert( pWInfo->pTabList!=0 );
+  if( pWInfo->pOrderBy==0 && (db->flags & SQLITE_ReverseOrder)!=0 ){
+    whereReverseScanOrder(pWInfo);
+  }
+  if( pParse->nErr ){
+    goto whereBeginError;
+  }
+  assert( db->mallocFailed==0 );
+#ifdef WHERETRACE_ENABLED
+  if( sqlite3WhereTrace ){
+    sqlite3DebugPrintf("---- Solution cost=%d, nRow=%d",
+                       pWInfo->rTotalCost, pWInfo->nRowOut);
+    if( pWInfo->nOBSat>0 ){
+      sqlite3DebugPrintf(" ORDERBY=%d,0x%llx", pWInfo->nOBSat, pWInfo->revMask);
+    }
+    switch( pWInfo->eDistinct ){
+      case WHERE_DISTINCT_UNIQUE: {
+        sqlite3DebugPrintf("  DISTINCT=unique");
+        break;
+      }
+      case WHERE_DISTINCT_ORDERED: {
+        sqlite3DebugPrintf("  DISTINCT=ordered");
+        break;
+      }
+      case WHERE_DISTINCT_UNORDERED: {
+        sqlite3DebugPrintf("  DISTINCT=unordered");
+        break;
+      }
+    }
+    sqlite3DebugPrintf("\n");
+    for(ii=0; ii<pWInfo->nLevel; ii++){
+      sqlite3WhereLoopPrint(pWInfo->a[ii].pWLoop, sWLB.pWC);
+    }
+  }
+#endif
+
+  /* Attempt to omit tables from a join that do not affect the result.
+  ** See the comment on whereOmitNoopJoin() for further information.
+  **
+  ** This query optimization is factored out into a separate "no-inline"
+  ** procedure to keep the sqlite3WhereBegin() procedure from becoming
+  ** too large.  If sqlite3WhereBegin() becomes too large, that prevents
+  ** some C-compiler optimizers from in-lining the
+  ** sqlite3WhereCodeOneLoopStart() procedure, and it is important to
+  ** in-line sqlite3WhereCodeOneLoopStart() for performance reasons.
+  */
+  notReady = ~(Bitmask)0;
+  if( pWInfo->nLevel>=2       /* Must be a join, or this opt8n is pointless */
+   && pResultSet!=0           /* Condition (1) */
+   && 0==(wctrlFlags & (WHERE_AGG_DISTINCT|WHERE_KEEP_ALL_JOINS)) /* (1),(6) */
+   && OptimizationEnabled(db, SQLITE_OmitNoopJoin)                /* (7) */
+  ){
+    notReady = whereOmitNoopJoin(pWInfo, notReady);
+    nTabList = pWInfo->nLevel;
+    assert( nTabList>0 );
+  }
+
+  /* Check to see if there are any SEARCH loops that might benefit from
+  ** using a Bloom filter.
+  */
+  if( pWInfo->nLevel>=2
+   && OptimizationEnabled(db, SQLITE_BloomFilter)
+  ){
+    whereCheckIfBloomFilterIsUseful(pWInfo);
+  }
+
+#if defined(WHERETRACE_ENABLED)
+  if( sqlite3WhereTrace & 0x4000 ){ /* Display all terms of the WHERE clause */
+    sqlite3DebugPrintf("---- WHERE clause at end of analysis:\n");
+    sqlite3WhereClausePrint(sWLB.pWC);
+  }
+  WHERETRACE(0xffffffff,("*** Optimizer Finished ***\n"));
+#endif
+  pWInfo->pParse->nQueryLoop += pWInfo->nRowOut;
+
+  /* If the caller is an UPDATE or DELETE statement that is requesting
+  ** to use a one-pass algorithm, determine if this is appropriate.
+  **
+  ** A one-pass approach can be used if the caller has requested one
+  ** and either (a) the scan visits at most one row or (b) each
+  ** of the following are true:
+  **
+  **   * the caller has indicated that a one-pass approach can be used
+  **     with multiple rows (by setting WHERE_ONEPASS_MULTIROW), and
+  **   * the table is not a virtual table, and
+  **   * either the scan does not use the OR optimization or the caller
+  **     is a DELETE operation (WHERE_DUPLICATES_OK is only specified
+  **     for DELETE).
+  **
+  ** The last qualification is because an UPDATE statement uses
+  ** WhereInfo.aiCurOnePass[1] to determine whether or not it really can
+  ** use a one-pass approach, and this is not set accurately for scans
+  ** that use the OR optimization.
+  */
+  assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
+  if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 ){
+    int wsFlags = pWInfo->a[0].pWLoop->wsFlags;
+    int bOnerow = (wsFlags & WHERE_ONEROW)!=0;
+    assert( !(wsFlags&WHERE_VIRTUALTABLE) || IsVirtual(pTabList->a[0].pSTab) );
+    if( bOnerow || (
+        0!=(wctrlFlags & WHERE_ONEPASS_MULTIROW)
+     && !IsVirtual(pTabList->a[0].pSTab)
+     && (0==(wsFlags & WHERE_MULTI_OR) || (wctrlFlags & WHERE_DUPLICATES_OK))
+     && OptimizationEnabled(db, SQLITE_OnePass)
+    )){
+      pWInfo->eOnePass = bOnerow ? ONEPASS_SINGLE : ONEPASS_MULTI;
+      if( HasRowid(pTabList->a[0].pSTab) && (wsFlags & WHERE_IDX_ONLY) ){
+        if( wctrlFlags & WHERE_ONEPASS_MULTIROW ){
+          bFordelete = OPFLAG_FORDELETE;
+        }
+        pWInfo->a[0].pWLoop->wsFlags = (wsFlags & ~WHERE_IDX_ONLY);
+      }
+    }
+  }
+
+  /* Open all tables in the pTabList and any indices selected for
+  ** searching those tables.
+  */
+  for(ii=0, pLevel=pWInfo->a; ii<nTabList; ii++, pLevel++){
+    Table *pTab;     /* Table to open */
+    int iDb;         /* Index of database containing table/index */
+    SrcItem *pTabItem;
+
+    pTabItem = &pTabList->a[pLevel->iFrom];
+    pTab = pTabItem->pSTab;
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    pLoop = pLevel->pWLoop;
+    if( (pTab->tabFlags & TF_Ephemeral)!=0 || IsView(pTab) ){
+      /* Do nothing */
+    }else
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+    if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
+      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
+      int iCur = pTabItem->iCursor;
+      sqlite3VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB);
+    }else if( IsVirtual(pTab) ){
+      /* noop */
+    }else
+#endif
+    if( ((pLoop->wsFlags & WHERE_IDX_ONLY)==0
+         && (wctrlFlags & WHERE_OR_SUBCLAUSE)==0)
+     || (pTabItem->fg.jointype & (JT_LTORJ|JT_RIGHT))!=0
+    ){
+      int op = OP_OpenRead;
+      if( pWInfo->eOnePass!=ONEPASS_OFF ){
+        op = OP_OpenWrite;
+        pWInfo->aiCurOnePass[0] = pTabItem->iCursor;
+      };
+      sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op);
+      assert( pTabItem->iCursor==pLevel->iTabCur );
+      testcase( pWInfo->eOnePass==ONEPASS_OFF && pTab->nCol==BMS-1 );
+      testcase( pWInfo->eOnePass==ONEPASS_OFF && pTab->nCol==BMS );
+      if( pWInfo->eOnePass==ONEPASS_OFF
+       && pTab->nCol<BMS
+       && (pTab->tabFlags & (TF_HasGenerated|TF_WithoutRowid))==0
+       && (pLoop->wsFlags & (WHERE_AUTO_INDEX|WHERE_BLOOMFILTER))==0
+      ){
+        /* If we know that only a prefix of the record will be used,
+        ** it is advantageous to reduce the "column count" field in
+        ** the P4 operand of the OP_OpenRead/Write opcode. */
+        Bitmask b = pTabItem->colUsed;
+        int n = 0;
+        for(; b; b=b>>1, n++){}
+        sqlite3VdbeChangeP4(v, -1, SQLITE_INT_TO_PTR(n), P4_INT32);
+        assert( n<=pTab->nCol );
+      }
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+      if( pLoop->u.btree.pIndex!=0 && (pTab->tabFlags & TF_WithoutRowid)==0 ){
+        sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ|bFordelete);
+      }else
+#endif
+      {
+        sqlite3VdbeChangeP5(v, bFordelete);
+      }
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+      sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, pTabItem->iCursor, 0, 0,
+                            (const u8*)&pTabItem->colUsed, P4_INT64);
+#endif
+    }else{
+      sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
+    }
+    if( pLoop->wsFlags & WHERE_INDEXED ){
+      Index *pIx = pLoop->u.btree.pIndex;
+      int iIndexCur;
+      int op = OP_OpenRead;
+      /* iAuxArg is always set to a positive value if ONEPASS is possible */
+      assert( iAuxArg!=0 || (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 );
+      if( !HasRowid(pTab) && IsPrimaryKeyIndex(pIx)
+       && (wctrlFlags & WHERE_OR_SUBCLAUSE)!=0
+      ){
+        /* This is one term of an OR-optimization using the PRIMARY KEY of a
+        ** WITHOUT ROWID table.  No need for a separate index */
+        iIndexCur = pLevel->iTabCur;
+        op = 0;
+      }else if( pWInfo->eOnePass!=ONEPASS_OFF ){
+        Index *pJ = pTabItem->pSTab->pIndex;
+        iIndexCur = iAuxArg;
+        assert( wctrlFlags & WHERE_ONEPASS_DESIRED );
+        while( ALWAYS(pJ) && pJ!=pIx ){
+          iIndexCur++;
+          pJ = pJ->pNext;
+        }
+        op = OP_OpenWrite;
+        pWInfo->aiCurOnePass[1] = iIndexCur;
+      }else if( iAuxArg && (wctrlFlags & WHERE_OR_SUBCLAUSE)!=0 ){
+        iIndexCur = iAuxArg;
+        op = OP_ReopenIdx;
+      }else{
+        iIndexCur = pParse->nTab++;
+        if( pIx->bHasExpr && OptimizationEnabled(db, SQLITE_IndexedExpr) ){
+          whereAddIndexedExpr(pParse, pIx, iIndexCur, pTabItem);
+        }
+        if( pIx->pPartIdxWhere && (pTabItem->fg.jointype & JT_RIGHT)==0 ){
+          wherePartIdxExpr(
+              pParse, pIx, pIx->pPartIdxWhere, 0, iIndexCur, pTabItem
+          );
+        }
+      }
+      pLevel->iIdxCur = iIndexCur;
+      assert( pIx!=0 );
+      assert( pIx->pSchema==pTab->pSchema );
+      assert( iIndexCur>=0 );
+      if( op ){
+        sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb);
+        sqlite3VdbeSetP4KeyInfo(pParse, pIx);
+        if( (pLoop->wsFlags & WHERE_CONSTRAINT)!=0
+         && (pLoop->wsFlags & (WHERE_COLUMN_RANGE|WHERE_SKIPSCAN))==0
+         && (pLoop->wsFlags & WHERE_BIGNULL_SORT)==0
+         && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0
+         && (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0
+         && pWInfo->eDistinct!=WHERE_DISTINCT_ORDERED
+        ){
+          sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ);
+        }
+        VdbeComment((v, "%s", pIx->zName));
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+        {
+          u64 colUsed = 0;
+          int ii, jj;
+          for(ii=0; ii<pIx->nColumn; ii++){
+            jj = pIx->aiColumn[ii];
+            if( jj<0 ) continue;
+            if( jj>63 ) jj = 63;
+            if( (pTabItem->colUsed & MASKBIT(jj))==0 ) continue;
+            colUsed |= ((u64)1)<<(ii<63 ? ii : 63);
+          }
+          sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, iIndexCur, 0, 0,
+                                (u8*)&colUsed, P4_INT64);
+        }
+#endif /* SQLITE_ENABLE_COLUMN_USED_MASK */
+      }
+    }
+    if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);
+    if( (pTabItem->fg.jointype & JT_RIGHT)!=0
+     && (pLevel->pRJ = sqlite3WhereMalloc(pWInfo, sizeof(WhereRightJoin)))!=0
+    ){
+      WhereRightJoin *pRJ = pLevel->pRJ;
+      pRJ->iMatch = pParse->nTab++;
+      pRJ->regBloom = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Blob, 65536, pRJ->regBloom);
+      pRJ->regReturn = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, pRJ->regReturn);
+      assert( pTab==pTabItem->pSTab );
+      if( HasRowid(pTab) ){
+        KeyInfo *pInfo;
+        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRJ->iMatch, 1);
+        pInfo = sqlite3KeyInfoAlloc(pParse->db, 1, 0);
+        if( pInfo ){
+          pInfo->aColl[0] = 0;
+          pInfo->aSortFlags[0] = 0;
+          sqlite3VdbeAppendP4(v, pInfo, P4_KEYINFO);
+        }
+      }else{
+        Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRJ->iMatch, pPk->nKeyCol);
+        sqlite3VdbeSetP4KeyInfo(pParse, pPk);
+      }
+      pLoop->wsFlags &= ~WHERE_IDX_ONLY;
+      /* The nature of RIGHT JOIN processing is such that it messes up
+      ** the output order.  So omit any ORDER BY/GROUP BY elimination
+      ** optimizations.  We need to do an actual sort for RIGHT JOIN. */
+      pWInfo->nOBSat = 0;
+      pWInfo->eDistinct = WHERE_DISTINCT_UNORDERED;
+    }
+  }
+  pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
+  if( db->mallocFailed ) goto whereBeginError;
+
+  /* Generate the code to do the search.  Each iteration of the for
+  ** loop below generates code for a single nested loop of the VM
+  ** program.
+  */
+  for(ii=0; ii<nTabList; ii++){
+    int addrExplain;
+    int wsFlags;
+    SrcItem *pSrc;
+    if( pParse->nErr ) goto whereBeginError;
+    pLevel = &pWInfo->a[ii];
+    wsFlags = pLevel->pWLoop->wsFlags;
+    pSrc = &pTabList->a[pLevel->iFrom];
+    if( pSrc->fg.isMaterialized ){
+      Subquery *pSubq;
+      int iOnce = 0;
+      assert( pSrc->fg.isSubquery );
+      pSubq = pSrc->u4.pSubq;
+      if( pSrc->fg.isCorrelated==0 ){
+        iOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
+      }else{
+        iOnce = 0;
+      }
+      sqlite3VdbeAddOp2(v, OP_Gosub, pSubq->regReturn, pSubq->addrFillSub);
+      VdbeComment((v, "materialize %!S", pSrc));
+      if( iOnce )  sqlite3VdbeJumpHere(v, iOnce);
+    }
+    assert( pTabList == pWInfo->pTabList );
+    if( (wsFlags & (WHERE_AUTO_INDEX|WHERE_BLOOMFILTER))!=0 ){
+      if( (wsFlags & WHERE_AUTO_INDEX)!=0 ){
+#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
+        constructAutomaticIndex(pParse, &pWInfo->sWC, notReady, pLevel);
+#endif
+      }else{
+        sqlite3ConstructBloomFilter(pWInfo, ii, pLevel, notReady);
+      }
+      if( db->mallocFailed ) goto whereBeginError;
+    }
+    addrExplain = sqlite3WhereExplainOneScan(
+        pParse, pTabList, pLevel, wctrlFlags
+    );
+    pLevel->addrBody = sqlite3VdbeCurrentAddr(v);
+    notReady = sqlite3WhereCodeOneLoopStart(pParse,v,pWInfo,ii,pLevel,notReady);
+    pWInfo->iContinue = pLevel->addrCont;
+    if( (wsFlags&WHERE_MULTI_OR)==0 && (wctrlFlags&WHERE_OR_SUBCLAUSE)==0 ){
+      sqlite3WhereAddScanStatus(v, pTabList, pLevel, addrExplain);
+    }
+  }
+
+  /* Done. */
+  VdbeModuleComment((v, "Begin WHERE-core"));
+  pWInfo->iEndWhere = sqlite3VdbeCurrentAddr(v);
+  return pWInfo;
+
+  /* Jump here if malloc fails */
+whereBeginError:
+  if( pWInfo ){
+    pParse->nQueryLoop = pWInfo->savedNQueryLoop;
+    whereInfoFree(db, pWInfo);
+  }
+#ifdef WHERETRACE_ENABLED
+  /* Prevent harmless compiler warnings about debugging routines
+  ** being declared but never used */
+  sqlite3ShowWhereLoopList(0);
+#endif /* WHERETRACE_ENABLED */
+  return 0;
+}
+
+/*
+** Part of sqlite3WhereEnd() will rewrite opcodes to reference the
+** index rather than the main table.  In SQLITE_DEBUG mode, we want
+** to trace those changes if PRAGMA vdbe_addoptrace=on.  This routine
+** does that.
+*/
+#ifndef SQLITE_DEBUG
+# define OpcodeRewriteTrace(D,K,P) /* no-op */
+#else
+# define OpcodeRewriteTrace(D,K,P) sqlite3WhereOpcodeRewriteTrace(D,K,P)
+  static void sqlite3WhereOpcodeRewriteTrace(
+    sqlite3 *db,
+    int pc,
+    VdbeOp *pOp
+  ){
+    if( (db->flags & SQLITE_VdbeAddopTrace)==0 ) return;
+    sqlite3VdbePrintOp(0, pc, pOp);
+    sqlite3ShowWhereTerm(0); /* So compiler won't complain about unused func */
+  }
+#endif
+
+/*
+** Generate the end of the WHERE loop.  See comments on
+** sqlite3WhereBegin() for additional information.
+*/
+SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo *pWInfo){
+  Parse *pParse = pWInfo->pParse;
+  Vdbe *v = pParse->pVdbe;
+  int i;
+  WhereLevel *pLevel;
+  WhereLoop *pLoop;
+  SrcList *pTabList = pWInfo->pTabList;
+  sqlite3 *db = pParse->db;
+  int iEnd = sqlite3VdbeCurrentAddr(v);
+  int nRJ = 0;
+
+  /* Generate loop termination code.
+  */
+  VdbeModuleComment((v, "End WHERE-core"));
+  for(i=pWInfo->nLevel-1; i>=0; i--){
+    int addr;
+    pLevel = &pWInfo->a[i];
+    if( pLevel->pRJ ){
+      /* Terminate the subroutine that forms the interior of the loop of
+      ** the RIGHT JOIN table */
+      WhereRightJoin *pRJ = pLevel->pRJ;
+      sqlite3VdbeResolveLabel(v, pLevel->addrCont);
+      pLevel->addrCont = 0;
+      pRJ->endSubrtn = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp3(v, OP_Return, pRJ->regReturn, pRJ->addrSubrtn, 1);
+      VdbeCoverage(v);
+      nRJ++;
+    }
+    pLoop = pLevel->pWLoop;
+    if( pLevel->op!=OP_Noop ){
+#ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT
+      int addrSeek = 0;
+      Index *pIdx;
+      int n;
+      if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED
+       && i==pWInfo->nLevel-1  /* Ticket [ef9318757b152e3] 2017-10-21 */
+       && (pLoop->wsFlags & WHERE_INDEXED)!=0
+       && (pIdx = pLoop->u.btree.pIndex)->hasStat1
+       && (n = pLoop->u.btree.nDistinctCol)>0
+       && pIdx->aiRowLogEst[n]>=36
+      ){
+        int r1 = pParse->nMem+1;
+        int j, op;
+        for(j=0; j<n; j++){
+          sqlite3VdbeAddOp3(v, OP_Column, pLevel->iIdxCur, j, r1+j);
+        }
+        pParse->nMem += n+1;
+        op = pLevel->op==OP_Prev ? OP_SeekLT : OP_SeekGT;
+        addrSeek = sqlite3VdbeAddOp4Int(v, op, pLevel->iIdxCur, 0, r1, n);
+        VdbeCoverageIf(v, op==OP_SeekLT);
+        VdbeCoverageIf(v, op==OP_SeekGT);
+        sqlite3VdbeAddOp2(v, OP_Goto, 1, pLevel->p2);
+      }
+#endif /* SQLITE_DISABLE_SKIPAHEAD_DISTINCT */
+      /* The common case: Advance to the next row */
+      if( pLevel->addrCont ) sqlite3VdbeResolveLabel(v, pLevel->addrCont);
+      sqlite3VdbeAddOp3(v, pLevel->op, pLevel->p1, pLevel->p2, pLevel->p3);
+      sqlite3VdbeChangeP5(v, pLevel->p5);
+      VdbeCoverage(v);
+      VdbeCoverageIf(v, pLevel->op==OP_Next);
+      VdbeCoverageIf(v, pLevel->op==OP_Prev);
+      VdbeCoverageIf(v, pLevel->op==OP_VNext);
+      if( pLevel->regBignull ){
+        sqlite3VdbeResolveLabel(v, pLevel->addrBignull);
+        sqlite3VdbeAddOp2(v, OP_DecrJumpZero, pLevel->regBignull, pLevel->p2-1);
+        VdbeCoverage(v);
+      }
+#ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT
+      if( addrSeek ) sqlite3VdbeJumpHere(v, addrSeek);
+#endif
+    }else if( pLevel->addrCont ){
+      sqlite3VdbeResolveLabel(v, pLevel->addrCont);
+    }
+    if( (pLoop->wsFlags & WHERE_IN_ABLE)!=0 && pLevel->u.in.nIn>0 ){
+      struct InLoop *pIn;
+      int j;
+      sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
+      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
+        assert( sqlite3VdbeGetOp(v, pIn->addrInTop+1)->opcode==OP_IsNull
+                 || pParse->db->mallocFailed );
+        sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
+        if( pIn->eEndLoopOp!=OP_Noop ){
+          if( pIn->nPrefix ){
+            int bEarlyOut =
+                (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0
+                 && (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0;
+            if( pLevel->iLeftJoin ){
+              /* For LEFT JOIN queries, cursor pIn->iCur may not have been
+              ** opened yet. This occurs for WHERE clauses such as
+              ** "a = ? AND b IN (...)", where the index is on (a, b). If
+              ** the RHS of the (a=?) is NULL, then the "b IN (...)" may
+              ** never have been coded, but the body of the loop run to
+              ** return the null-row. So, if the cursor is not open yet,
+              ** jump over the OP_Next or OP_Prev instruction about to
+              ** be coded.  */
+              sqlite3VdbeAddOp2(v, OP_IfNotOpen, pIn->iCur,
+                  sqlite3VdbeCurrentAddr(v) + 2 + bEarlyOut);
+              VdbeCoverage(v);
+            }
+            if( bEarlyOut ){
+              sqlite3VdbeAddOp4Int(v, OP_IfNoHope, pLevel->iIdxCur,
+                  sqlite3VdbeCurrentAddr(v)+2,
+                  pIn->iBase, pIn->nPrefix);
+              VdbeCoverage(v);
+              /* Retarget the OP_IsNull against the left operand of IN so
+              ** it jumps past the OP_IfNoHope.  This is because the
+              ** OP_IsNull also bypasses the OP_Affinity opcode that is
+              ** required by OP_IfNoHope. */
+              sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
+            }
+          }
+          sqlite3VdbeAddOp2(v, pIn->eEndLoopOp, pIn->iCur, pIn->addrInTop);
+          VdbeCoverage(v);
+          VdbeCoverageIf(v, pIn->eEndLoopOp==OP_Prev);
+          VdbeCoverageIf(v, pIn->eEndLoopOp==OP_Next);
+        }
+        sqlite3VdbeJumpHere(v, pIn->addrInTop-1);
+      }
+    }
+    sqlite3VdbeResolveLabel(v, pLevel->addrBrk);
+    if( pLevel->pRJ ){
+      sqlite3VdbeAddOp3(v, OP_Return, pLevel->pRJ->regReturn, 0, 1);
+      VdbeCoverage(v);
+    }
+    if( pLevel->addrSkip ){
+      sqlite3VdbeGoto(v, pLevel->addrSkip);
+      VdbeComment((v, "next skip-scan on %s", pLoop->u.btree.pIndex->zName));
+      sqlite3VdbeJumpHere(v, pLevel->addrSkip);
+      sqlite3VdbeJumpHere(v, pLevel->addrSkip-2);
+    }
+#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
+    if( pLevel->addrLikeRep ){
+      sqlite3VdbeAddOp2(v, OP_DecrJumpZero, (int)(pLevel->iLikeRepCntr>>1),
+                        pLevel->addrLikeRep);
+      VdbeCoverage(v);
+    }
+#endif
+    if( pLevel->iLeftJoin ){
+      int ws = pLoop->wsFlags;
+      addr = sqlite3VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin); VdbeCoverage(v);
+      assert( (ws & WHERE_IDX_ONLY)==0 || (ws & WHERE_INDEXED)!=0 );
+      if( (ws & WHERE_IDX_ONLY)==0 ){
+        SrcItem *pSrc = &pTabList->a[pLevel->iFrom];
+        assert( pLevel->iTabCur==pSrc->iCursor );
+        if( pSrc->fg.viaCoroutine ){
+          int m, n;
+          assert( pSrc->fg.isSubquery );
+          n = pSrc->u4.pSubq->regResult;
+          assert( pSrc->pSTab!=0 );
+          m = pSrc->pSTab->nCol;
+          sqlite3VdbeAddOp3(v, OP_Null, 0, n, n+m-1);
+        }
+        sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iTabCur);
+      }
+      if( (ws & WHERE_INDEXED)
+       || ((ws & WHERE_MULTI_OR) && pLevel->u.pCoveringIdx)
+      ){
+        if( ws & WHERE_MULTI_OR ){
+          Index *pIx = pLevel->u.pCoveringIdx;
+          int iDb = sqlite3SchemaToIndex(db, pIx->pSchema);
+          sqlite3VdbeAddOp3(v, OP_ReopenIdx, pLevel->iIdxCur, pIx->tnum, iDb);
+          sqlite3VdbeSetP4KeyInfo(pParse, pIx);
+        }
+        sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
+      }
+      if( pLevel->op==OP_Return ){
+        sqlite3VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
+      }else{
+        sqlite3VdbeGoto(v, pLevel->addrFirst);
+      }
+      sqlite3VdbeJumpHere(v, addr);
+    }
+    VdbeModuleComment((v, "End WHERE-loop%d: %s", i,
+                     pWInfo->pTabList->a[pLevel->iFrom].pSTab->zName));
+  }
+
+  assert( pWInfo->nLevel<=pTabList->nSrc );
+  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
+    int k, last;
+    VdbeOp *pOp, *pLastOp;
+    Index *pIdx = 0;
+    SrcItem *pTabItem = &pTabList->a[pLevel->iFrom];
+    Table *pTab = pTabItem->pSTab;
+    assert( pTab!=0 );
+    pLoop = pLevel->pWLoop;
+
+    /* Do RIGHT JOIN processing.  Generate code that will output the
+    ** unmatched rows of the right operand of the RIGHT JOIN with
+    ** all of the columns of the left operand set to NULL.
+    */
+    if( pLevel->pRJ ){
+      sqlite3WhereRightJoinLoop(pWInfo, i, pLevel);
+      continue;
+    }
+
+    /* For a co-routine, change all OP_Column references to the table of
+    ** the co-routine into OP_Copy of result contained in a register.
+    ** OP_Rowid becomes OP_Null.
+    */
+    if( pTabItem->fg.viaCoroutine ){
+      testcase( pParse->db->mallocFailed );
+      assert( pTabItem->fg.isSubquery );
+      assert( pTabItem->u4.pSubq->regResult>=0 );
+      translateColumnToCopy(pParse, pLevel->addrBody, pLevel->iTabCur,
+                            pTabItem->u4.pSubq->regResult, 0);
+      continue;
+    }
+
+    /* If this scan uses an index, make VDBE code substitutions to read data
+    ** from the index instead of from the table where possible.  In some cases
+    ** this optimization prevents the table from ever being read, which can
+    ** yield a significant performance boost.
+    **
+    ** Calls to the code generator in between sqlite3WhereBegin and
+    ** sqlite3WhereEnd will have created code that references the table
+    ** directly.  This loop scans all that code looking for opcodes
+    ** that reference the table and converts them into opcodes that
+    ** reference the index.
+    */
+    if( pLoop->wsFlags & (WHERE_INDEXED|WHERE_IDX_ONLY) ){
+      pIdx = pLoop->u.btree.pIndex;
+    }else if( pLoop->wsFlags & WHERE_MULTI_OR ){
+      pIdx = pLevel->u.pCoveringIdx;
+    }
+    if( pIdx
+     && !db->mallocFailed
+    ){
+      if( pWInfo->eOnePass==ONEPASS_OFF || !HasRowid(pIdx->pTable) ){
+        last = iEnd;
+      }else{
+        last = pWInfo->iEndWhere;
+      }
+      if( pIdx->bHasExpr ){
+        IndexedExpr *p = pParse->pIdxEpr;
+        while( p ){
+          if( p->iIdxCur==pLevel->iIdxCur ){
+#ifdef WHERETRACE_ENABLED
+            if( sqlite3WhereTrace & 0x200 ){
+              sqlite3DebugPrintf("Disable pParse->pIdxEpr term {%d,%d}\n",
+                                  p->iIdxCur, p->iIdxCol);
+              if( sqlite3WhereTrace & 0x5000 ) sqlite3ShowExpr(p->pExpr);
+            }
+#endif
+            p->iDataCur = -1;
+            p->iIdxCur = -1;
+          }
+          p = p->pIENext;
+        }
+      }
+      k = pLevel->addrBody + 1;
+#ifdef SQLITE_DEBUG
+      if( db->flags & SQLITE_VdbeAddopTrace ){
+        printf("TRANSLATE cursor %d->%d in opcode range %d..%d\n",
+                pLevel->iTabCur, pLevel->iIdxCur, k, last-1);
+      }
+      /* Proof that the "+1" on the k value above is safe */
+      pOp = sqlite3VdbeGetOp(v, k - 1);
+      assert( pOp->opcode!=OP_Column || pOp->p1!=pLevel->iTabCur );
+      assert( pOp->opcode!=OP_Rowid  || pOp->p1!=pLevel->iTabCur );
+      assert( pOp->opcode!=OP_IfNullRow || pOp->p1!=pLevel->iTabCur );
+#endif
+      pOp = sqlite3VdbeGetOp(v, k);
+      pLastOp = pOp + (last - k);
+      assert( pOp<=pLastOp );
+      do{
+        if( pOp->p1!=pLevel->iTabCur ){
+          /* no-op */
+        }else if( pOp->opcode==OP_Column
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+         || pOp->opcode==OP_Offset
+#endif
+        ){
+          int x = pOp->p2;
+          assert( pIdx->pTable==pTab );
+#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
+          if( pOp->opcode==OP_Offset ){
+            /* Do not need to translate the column number */
+          }else
+#endif
+          if( !HasRowid(pTab) ){
+            Index *pPk = sqlite3PrimaryKeyIndex(pTab);
+            x = pPk->aiColumn[x];
+            assert( x>=0 );
+          }else{
+            testcase( x!=sqlite3StorageColumnToTable(pTab,x) );
+            x = sqlite3StorageColumnToTable(pTab,x);
+          }
+          x = sqlite3TableColumnToIndex(pIdx, x);
+          if( x>=0 ){
+            pOp->p2 = x;
+            pOp->p1 = pLevel->iIdxCur;
+            OpcodeRewriteTrace(db, k, pOp);
+          }else if( pLoop->wsFlags & (WHERE_IDX_ONLY|WHERE_EXPRIDX) ){
+            if( pLoop->wsFlags & WHERE_IDX_ONLY ){
+              /* An error. pLoop is supposed to be a covering index loop,
+              ** and yet the VM code refers to a column of the table that
+              ** is not part of the index.  */
+              sqlite3ErrorMsg(pParse, "internal query planner error");
+              pParse->rc = SQLITE_INTERNAL;
+            }else{
+              /* The WHERE_EXPRIDX flag is set by the planner when it is likely
+              ** that pLoop is a covering index loop, but it is not possible
+              ** to be 100% sure. In this case, any OP_Explain opcode
+              ** corresponding to this loop describes the index as a "COVERING
+              ** INDEX". But, pOp proves that pLoop is not actually a covering
+              ** index loop. So clear the WHERE_EXPRIDX flag and rewrite the
+              ** text that accompanies the OP_Explain opcode, if any.  */
+              pLoop->wsFlags &= ~WHERE_EXPRIDX;
+              sqlite3WhereAddExplainText(pParse,
+                  pLevel->addrBody-1,
+                  pTabList,
+                  pLevel,
+                  pWInfo->wctrlFlags
+              );
+            }
+          }
+        }else if( pOp->opcode==OP_Rowid ){
+          pOp->p1 = pLevel->iIdxCur;
+          pOp->opcode = OP_IdxRowid;
+          OpcodeRewriteTrace(db, k, pOp);
+        }else if( pOp->opcode==OP_IfNullRow ){
+          pOp->p1 = pLevel->iIdxCur;
+          OpcodeRewriteTrace(db, k, pOp);
+        }
+#ifdef SQLITE_DEBUG
+        k++;
+#endif
+      }while( (++pOp)<pLastOp );
+#ifdef SQLITE_DEBUG
+      if( db->flags & SQLITE_VdbeAddopTrace ) printf("TRANSLATE complete\n");
+#endif
+    }
+  }
+
+  /* The "break" point is here, just past the end of the outer loop.
+  ** Set it.
+  */
+  sqlite3VdbeResolveLabel(v, pWInfo->iBreak);
+
+  /* Final cleanup
+  */
+  pParse->nQueryLoop = pWInfo->savedNQueryLoop;
+  whereInfoFree(db, pWInfo);
+  pParse->withinRJSubrtn -= nRJ;
+  return;
+}
+
+/************** End of where.c ***********************************************/
+/************** Begin file window.c ******************************************/
+/*
+** 2018 May 08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+/* #include "sqliteInt.h" */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+
+/*
+** SELECT REWRITING
+**
+**   Any SELECT statement that contains one or more window functions in
+**   either the select list or ORDER BY clause (the only two places window
+**   functions may be used) is transformed by function sqlite3WindowRewrite()
+**   in order to support window function processing. For example, with the
+**   schema:
+**
+**     CREATE TABLE t1(a, b, c, d, e, f, g);
+**
+**   the statement:
+**
+**     SELECT a+1, max(b) OVER (PARTITION BY c ORDER BY d) FROM t1 ORDER BY e;
+**
+**   is transformed to:
+**
+**     SELECT a+1, max(b) OVER (PARTITION BY c ORDER BY d) FROM (
+**         SELECT a, e, c, d, b FROM t1 ORDER BY c, d
+**     ) ORDER BY e;
+**
+**   The flattening optimization is disabled when processing this transformed
+**   SELECT statement. This allows the implementation of the window function
+**   (in this case max()) to process rows sorted in order of (c, d), which
+**   makes things easier for obvious reasons. More generally:
+**
+**     * FROM, WHERE, GROUP BY and HAVING clauses are all moved to
+**       the sub-query.
+**
+**     * ORDER BY, LIMIT and OFFSET remain part of the parent query.
+**
+**     * Terminals from each of the expression trees that make up the
+**       select-list and ORDER BY expressions in the parent query are
+**       selected by the sub-query. For the purposes of the transformation,
+**       terminals are column references and aggregate functions.
+**
+**   If there is more than one window function in the SELECT that uses
+**   the same window declaration (the OVER bit), then a single scan may
+**   be used to process more than one window function. For example:
+**
+**     SELECT max(b) OVER (PARTITION BY c ORDER BY d),
+**            min(e) OVER (PARTITION BY c ORDER BY d)
+**     FROM t1;
+**
+**   is transformed in the same way as the example above. However:
+**
+**     SELECT max(b) OVER (PARTITION BY c ORDER BY d),
+**            min(e) OVER (PARTITION BY a ORDER BY b)
+**     FROM t1;
+**
+**   Must be transformed to:
+**
+**     SELECT max(b) OVER (PARTITION BY c ORDER BY d) FROM (
+**         SELECT e, min(e) OVER (PARTITION BY a ORDER BY b), c, d, b FROM
+**           SELECT a, e, c, d, b FROM t1 ORDER BY a, b
+**         ) ORDER BY c, d
+**     ) ORDER BY e;
+**
+**   so that both min() and max() may process rows in the order defined by
+**   their respective window declarations.
+**
+** INTERFACE WITH SELECT.C
+**
+**   When processing the rewritten SELECT statement, code in select.c calls
+**   sqlite3WhereBegin() to begin iterating through the results of the
+**   sub-query, which is always implemented as a co-routine. It then calls
+**   sqlite3WindowCodeStep() to process rows and finish the scan by calling
+**   sqlite3WhereEnd().
+**
+**   sqlite3WindowCodeStep() generates VM code so that, for each row returned
+**   by the sub-query a sub-routine (OP_Gosub) coded by select.c is invoked.
+**   When the sub-routine is invoked:
+**
+**     * The results of all window-functions for the row are stored
+**       in the associated Window.regResult registers.
+**
+**     * The required terminal values are stored in the current row of
+**       temp table Window.iEphCsr.
+**
+**   In some cases, depending on the window frame and the specific window
+**   functions invoked, sqlite3WindowCodeStep() caches each entire partition
+**   in a temp table before returning any rows. In other cases it does not.
+**   This detail is encapsulated within this file, the code generated by
+**   select.c is the same in either case.
+**
+** BUILT-IN WINDOW FUNCTIONS
+**
+**   This implementation features the following built-in window functions:
+**
+**     row_number()
+**     rank()
+**     dense_rank()
+**     percent_rank()
+**     cume_dist()
+**     ntile(N)
+**     lead(expr [, offset [, default]])
+**     lag(expr [, offset [, default]])
+**     first_value(expr)
+**     last_value(expr)
+**     nth_value(expr, N)
+**
+**   These are the same built-in window functions supported by Postgres.
+**   Although the behaviour of aggregate window functions (functions that
+**   can be used as either aggregates or window functions) allows them to
+**   be implemented using an API, built-in window functions are much more
+**   esoteric. Additionally, some window functions (e.g. nth_value())
+**   may only be implemented by caching the entire partition in memory.
+**   As such, some built-in window functions use the same API as aggregate
+**   window functions and some are implemented directly using VDBE
+**   instructions. Additionally, for those functions that use the API, the
+**   window frame is sometimes modified before the SELECT statement is
+**   rewritten. For example, regardless of the specified window frame, the
+**   row_number() function always uses:
+**
+**     ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+**
+**   See sqlite3WindowUpdate() for details.
+**
+**   As well as some of the built-in window functions, aggregate window
+**   functions min() and max() are implemented using VDBE instructions if
+**   the start of the window frame is declared as anything other than
+**   UNBOUNDED PRECEDING.
+*/
+
+/*
+** Implementation of built-in window function row_number(). Assumes that the
+** window frame has been coerced to:
+**
+**   ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+*/
+static void row_numberStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  i64 *p = (i64*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ) (*p)++;
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+}
+static void row_numberValueFunc(sqlite3_context *pCtx){
+  i64 *p = (i64*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  sqlite3_result_int64(pCtx, (p ? *p : 0));
+}
+
+/*
+** Context object type used by rank(), dense_rank(), percent_rank() and
+** cume_dist().
+*/
+struct CallCount {
+  i64 nValue;
+  i64 nStep;
+  i64 nTotal;
+};
+
+/*
+** Implementation of built-in window function dense_rank(). Assumes that
+** the window frame has been set to:
+**
+**   RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+*/
+static void dense_rankStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ) p->nStep = 1;
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+}
+static void dense_rankValueFunc(sqlite3_context *pCtx){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    if( p->nStep ){
+      p->nValue++;
+      p->nStep = 0;
+    }
+    sqlite3_result_int64(pCtx, p->nValue);
+  }
+}
+
+/*
+** Implementation of built-in window function nth_value(). This
+** implementation is used in "slow mode" only - when the EXCLUDE clause
+** is not set to the default value "NO OTHERS".
+*/
+struct NthValueCtx {
+  i64 nStep;
+  sqlite3_value *pValue;
+};
+static void nth_valueStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct NthValueCtx *p;
+  p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    i64 iVal;
+    switch( sqlite3_value_numeric_type(apArg[1]) ){
+      case SQLITE_INTEGER:
+        iVal = sqlite3_value_int64(apArg[1]);
+        break;
+      case SQLITE_FLOAT: {
+        double fVal = sqlite3_value_double(apArg[1]);
+        if( ((i64)fVal)!=fVal ) goto error_out;
+        iVal = (i64)fVal;
+        break;
+      }
+      default:
+        goto error_out;
+    }
+    if( iVal<=0 ) goto error_out;
+
+    p->nStep++;
+    if( iVal==p->nStep ){
+      p->pValue = sqlite3_value_dup(apArg[0]);
+      if( !p->pValue ){
+        sqlite3_result_error_nomem(pCtx);
+      }
+    }
+  }
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+  return;
+
+ error_out:
+  sqlite3_result_error(
+      pCtx, "second argument to nth_value must be a positive integer", -1
+  );
+}
+static void nth_valueFinalizeFunc(sqlite3_context *pCtx){
+  struct NthValueCtx *p;
+  p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, 0);
+  if( p && p->pValue ){
+    sqlite3_result_value(pCtx, p->pValue);
+    sqlite3_value_free(p->pValue);
+    p->pValue = 0;
+  }
+}
+#define nth_valueInvFunc noopStepFunc
+#define nth_valueValueFunc noopValueFunc
+
+static void first_valueStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct NthValueCtx *p;
+  p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p && p->pValue==0 ){
+    p->pValue = sqlite3_value_dup(apArg[0]);
+    if( !p->pValue ){
+      sqlite3_result_error_nomem(pCtx);
+    }
+  }
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+}
+static void first_valueFinalizeFunc(sqlite3_context *pCtx){
+  struct NthValueCtx *p;
+  p = (struct NthValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p && p->pValue ){
+    sqlite3_result_value(pCtx, p->pValue);
+    sqlite3_value_free(p->pValue);
+    p->pValue = 0;
+  }
+}
+#define first_valueInvFunc noopStepFunc
+#define first_valueValueFunc noopValueFunc
+
+/*
+** Implementation of built-in window function rank(). Assumes that
+** the window frame has been set to:
+**
+**   RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
+*/
+static void rankStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    p->nStep++;
+    if( p->nValue==0 ){
+      p->nValue = p->nStep;
+    }
+  }
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+}
+static void rankValueFunc(sqlite3_context *pCtx){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    sqlite3_result_int64(pCtx, p->nValue);
+    p->nValue = 0;
+  }
+}
+
+/*
+** Implementation of built-in window function percent_rank(). Assumes that
+** the window frame has been set to:
+**
+**   GROUPS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+*/
+static void percent_rankStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  UNUSED_PARAMETER(nArg); assert( nArg==0 );
+  UNUSED_PARAMETER(apArg);
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    p->nTotal++;
+  }
+}
+static void percent_rankInvFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  UNUSED_PARAMETER(nArg); assert( nArg==0 );
+  UNUSED_PARAMETER(apArg);
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  p->nStep++;
+}
+static void percent_rankValueFunc(sqlite3_context *pCtx){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    p->nValue = p->nStep;
+    if( p->nTotal>1 ){
+      double r = (double)p->nValue / (double)(p->nTotal-1);
+      sqlite3_result_double(pCtx, r);
+    }else{
+      sqlite3_result_double(pCtx, 0.0);
+    }
+  }
+}
+#define percent_rankFinalizeFunc percent_rankValueFunc
+
+/*
+** Implementation of built-in window function cume_dist(). Assumes that
+** the window frame has been set to:
+**
+**   GROUPS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING
+*/
+static void cume_distStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  UNUSED_PARAMETER(nArg); assert( nArg==0 );
+  UNUSED_PARAMETER(apArg);
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    p->nTotal++;
+  }
+}
+static void cume_distInvFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct CallCount *p;
+  UNUSED_PARAMETER(nArg); assert( nArg==0 );
+  UNUSED_PARAMETER(apArg);
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  p->nStep++;
+}
+static void cume_distValueFunc(sqlite3_context *pCtx){
+  struct CallCount *p;
+  p = (struct CallCount*)sqlite3_aggregate_context(pCtx, 0);
+  if( p ){
+    double r = (double)(p->nStep) / (double)(p->nTotal);
+    sqlite3_result_double(pCtx, r);
+  }
+}
+#define cume_distFinalizeFunc cume_distValueFunc
+
+/*
+** Context object for ntile() window function.
+*/
+struct NtileCtx {
+  i64 nTotal;                     /* Total rows in partition */
+  i64 nParam;                     /* Parameter passed to ntile(N) */
+  i64 iRow;                       /* Current row */
+};
+
+/*
+** Implementation of ntile(). This assumes that the window frame has
+** been coerced to:
+**
+**   ROWS CURRENT ROW AND UNBOUNDED FOLLOWING
+*/
+static void ntileStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct NtileCtx *p;
+  assert( nArg==1 ); UNUSED_PARAMETER(nArg);
+  p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    if( p->nTotal==0 ){
+      p->nParam = sqlite3_value_int64(apArg[0]);
+      if( p->nParam<=0 ){
+        sqlite3_result_error(
+            pCtx, "argument of ntile must be a positive integer", -1
+        );
+      }
+    }
+    p->nTotal++;
+  }
+}
+static void ntileInvFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct NtileCtx *p;
+  assert( nArg==1 ); UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+  p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  p->iRow++;
+}
+static void ntileValueFunc(sqlite3_context *pCtx){
+  struct NtileCtx *p;
+  p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p && p->nParam>0 ){
+    int nSize = (p->nTotal / p->nParam);
+    if( nSize==0 ){
+      sqlite3_result_int64(pCtx, p->iRow+1);
+    }else{
+      i64 nLarge = p->nTotal - p->nParam*nSize;
+      i64 iSmall = nLarge*(nSize+1);
+      i64 iRow = p->iRow;
+
+      assert( (nLarge*(nSize+1) + (p->nParam-nLarge)*nSize)==p->nTotal );
+
+      if( iRow<iSmall ){
+        sqlite3_result_int64(pCtx, 1 + iRow/(nSize+1));
+      }else{
+        sqlite3_result_int64(pCtx, 1 + nLarge + (iRow-iSmall)/nSize);
+      }
+    }
+  }
+}
+#define ntileFinalizeFunc ntileValueFunc
+
+/*
+** Context object for last_value() window function.
+*/
+struct LastValueCtx {
+  sqlite3_value *pVal;
+  int nVal;
+};
+
+/*
+** Implementation of last_value().
+*/
+static void last_valueStepFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct LastValueCtx *p;
+  UNUSED_PARAMETER(nArg);
+  p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p ){
+    sqlite3_value_free(p->pVal);
+    p->pVal = sqlite3_value_dup(apArg[0]);
+    if( p->pVal==0 ){
+      sqlite3_result_error_nomem(pCtx);
+    }else{
+      p->nVal++;
+    }
+  }
+}
+static void last_valueInvFunc(
+  sqlite3_context *pCtx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  struct LastValueCtx *p;
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(apArg);
+  p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( ALWAYS(p) ){
+    p->nVal--;
+    if( p->nVal==0 ){
+      sqlite3_value_free(p->pVal);
+      p->pVal = 0;
+    }
+  }
+}
+static void last_valueValueFunc(sqlite3_context *pCtx){
+  struct LastValueCtx *p;
+  p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, 0);
+  if( p && p->pVal ){
+    sqlite3_result_value(pCtx, p->pVal);
+  }
+}
+static void last_valueFinalizeFunc(sqlite3_context *pCtx){
+  struct LastValueCtx *p;
+  p = (struct LastValueCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
+  if( p && p->pVal ){
+    sqlite3_result_value(pCtx, p->pVal);
+    sqlite3_value_free(p->pVal);
+    p->pVal = 0;
+  }
+}
+
+/*
+** Static names for the built-in window function names.  These static
+** names are used, rather than string literals, so that FuncDef objects
+** can be associated with a particular window function by direct
+** comparison of the zName pointer.  Example:
+**
+**       if( pFuncDef->zName==row_valueName ){ ... }
+*/
+static const char row_numberName[] =   "row_number";
+static const char dense_rankName[] =   "dense_rank";
+static const char rankName[] =         "rank";
+static const char percent_rankName[] = "percent_rank";
+static const char cume_distName[] =    "cume_dist";
+static const char ntileName[] =        "ntile";
+static const char last_valueName[] =   "last_value";
+static const char nth_valueName[] =    "nth_value";
+static const char first_valueName[] =  "first_value";
+static const char leadName[] =         "lead";
+static const char lagName[] =          "lag";
+
+/*
+** No-op implementations of xStep() and xFinalize().  Used as place-holders
+** for built-in window functions that never call those interfaces.
+**
+** The noopValueFunc() is called but is expected to do nothing.  The
+** noopStepFunc() is never called, and so it is marked with NO_TEST to
+** let the test coverage routine know not to expect this function to be
+** invoked.
+*/
+static void noopStepFunc(    /*NO_TEST*/
+  sqlite3_context *p,        /*NO_TEST*/
+  int n,                     /*NO_TEST*/
+  sqlite3_value **a          /*NO_TEST*/
+){                           /*NO_TEST*/
+  UNUSED_PARAMETER(p);       /*NO_TEST*/
+  UNUSED_PARAMETER(n);       /*NO_TEST*/
+  UNUSED_PARAMETER(a);       /*NO_TEST*/
+  assert(0);                 /*NO_TEST*/
+}                            /*NO_TEST*/
+static void noopValueFunc(sqlite3_context *p){ UNUSED_PARAMETER(p); /*no-op*/ }
+
+/* Window functions that use all window interfaces: xStep, xFinal,
+** xValue, and xInverse */
+#define WINDOWFUNCALL(name,nArg,extra) {                                   \
+  nArg, (SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_FUNC_WINDOW|extra), 0, 0,  \
+  name ## StepFunc, name ## FinalizeFunc, name ## ValueFunc,               \
+  name ## InvFunc, name ## Name, {0}                                       \
+}
+
+/* Window functions that are implemented using bytecode and thus have
+** no-op routines for their methods */
+#define WINDOWFUNCNOOP(name,nArg,extra) {                                  \
+  nArg, (SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_FUNC_WINDOW|extra), 0, 0,  \
+  noopStepFunc, noopValueFunc, noopValueFunc,                              \
+  noopStepFunc, name ## Name, {0}                                          \
+}
+
+/* Window functions that use all window interfaces: xStep, the
+** same routine for xFinalize and xValue and which never call
+** xInverse. */
+#define WINDOWFUNCX(name,nArg,extra) {                                     \
+  nArg, (SQLITE_FUNC_BUILTIN|SQLITE_UTF8|SQLITE_FUNC_WINDOW|extra), 0, 0,  \
+  name ## StepFunc, name ## ValueFunc, name ## ValueFunc,                  \
+  noopStepFunc, name ## Name, {0}                                          \
+}
+
+
+/*
+** Register those built-in window functions that are not also aggregates.
+*/
+SQLITE_PRIVATE void sqlite3WindowFunctions(void){
+  static FuncDef aWindowFuncs[] = {
+    WINDOWFUNCX(row_number, 0, 0),
+    WINDOWFUNCX(dense_rank, 0, 0),
+    WINDOWFUNCX(rank, 0, 0),
+    WINDOWFUNCALL(percent_rank, 0, 0),
+    WINDOWFUNCALL(cume_dist, 0, 0),
+    WINDOWFUNCALL(ntile, 1, 0),
+    WINDOWFUNCALL(last_value, 1, 0),
+    WINDOWFUNCALL(nth_value, 2, 0),
+    WINDOWFUNCALL(first_value, 1, 0),
+    WINDOWFUNCNOOP(lead, 1, 0),
+    WINDOWFUNCNOOP(lead, 2, 0),
+    WINDOWFUNCNOOP(lead, 3, 0),
+    WINDOWFUNCNOOP(lag, 1, 0),
+    WINDOWFUNCNOOP(lag, 2, 0),
+    WINDOWFUNCNOOP(lag, 3, 0),
+  };
+  sqlite3InsertBuiltinFuncs(aWindowFuncs, ArraySize(aWindowFuncs));
+}
+
+static Window *windowFind(Parse *pParse, Window *pList, const char *zName){
+  Window *p;
+  for(p=pList; p; p=p->pNextWin){
+    if( sqlite3StrICmp(p->zName, zName)==0 ) break;
+  }
+  if( p==0 ){
+    sqlite3ErrorMsg(pParse, "no such window: %s", zName);
+  }
+  return p;
+}
+
+/*
+** This function is called immediately after resolving the function name
+** for a window function within a SELECT statement. Argument pList is a
+** linked list of WINDOW definitions for the current SELECT statement.
+** Argument pFunc is the function definition just resolved and pWin
+** is the Window object representing the associated OVER clause. This
+** function updates the contents of pWin as follows:
+**
+**   * If the OVER clause referred to a named window (as in "max(x) OVER win"),
+**     search list pList for a matching WINDOW definition, and update pWin
+**     accordingly. If no such WINDOW clause can be found, leave an error
+**     in pParse.
+**
+**   * If the function is a built-in window function that requires the
+**     window to be coerced (see "BUILT-IN WINDOW FUNCTIONS" at the top
+**     of this file), pWin is updated here.
+*/
+SQLITE_PRIVATE void sqlite3WindowUpdate(
+  Parse *pParse,
+  Window *pList,                  /* List of named windows for this SELECT */
+  Window *pWin,                   /* Window frame to update */
+  FuncDef *pFunc                  /* Window function definition */
+){
+  if( pWin->zName && pWin->eFrmType==0 ){
+    Window *p = windowFind(pParse, pList, pWin->zName);
+    if( p==0 ) return;
+    pWin->pPartition = sqlite3ExprListDup(pParse->db, p->pPartition, 0);
+    pWin->pOrderBy = sqlite3ExprListDup(pParse->db, p->pOrderBy, 0);
+    pWin->pStart = sqlite3ExprDup(pParse->db, p->pStart, 0);
+    pWin->pEnd = sqlite3ExprDup(pParse->db, p->pEnd, 0);
+    pWin->eStart = p->eStart;
+    pWin->eEnd = p->eEnd;
+    pWin->eFrmType = p->eFrmType;
+    pWin->eExclude = p->eExclude;
+  }else{
+    sqlite3WindowChain(pParse, pWin, pList);
+  }
+  if( (pWin->eFrmType==TK_RANGE)
+   && (pWin->pStart || pWin->pEnd)
+   && (pWin->pOrderBy==0 || pWin->pOrderBy->nExpr!=1)
+  ){
+    sqlite3ErrorMsg(pParse,
+      "RANGE with offset PRECEDING/FOLLOWING requires one ORDER BY expression"
+    );
+  }else
+  if( pFunc->funcFlags & SQLITE_FUNC_WINDOW ){
+    sqlite3 *db = pParse->db;
+    if( pWin->pFilter ){
+      sqlite3ErrorMsg(pParse,
+          "FILTER clause may only be used with aggregate window functions"
+      );
+    }else{
+      struct WindowUpdate {
+        const char *zFunc;
+        int eFrmType;
+        int eStart;
+        int eEnd;
+      } aUp[] = {
+        { row_numberName,   TK_ROWS,   TK_UNBOUNDED, TK_CURRENT },
+        { dense_rankName,   TK_RANGE,  TK_UNBOUNDED, TK_CURRENT },
+        { rankName,         TK_RANGE,  TK_UNBOUNDED, TK_CURRENT },
+        { percent_rankName, TK_GROUPS, TK_CURRENT,   TK_UNBOUNDED },
+        { cume_distName,    TK_GROUPS, TK_FOLLOWING, TK_UNBOUNDED },
+        { ntileName,        TK_ROWS,   TK_CURRENT,   TK_UNBOUNDED },
+        { leadName,         TK_ROWS,   TK_UNBOUNDED, TK_UNBOUNDED },
+        { lagName,          TK_ROWS,   TK_UNBOUNDED, TK_CURRENT },
+      };
+      int i;
+      for(i=0; i<ArraySize(aUp); i++){
+        if( pFunc->zName==aUp[i].zFunc ){
+          sqlite3ExprDelete(db, pWin->pStart);
+          sqlite3ExprDelete(db, pWin->pEnd);
+          pWin->pEnd = pWin->pStart = 0;
+          pWin->eFrmType = aUp[i].eFrmType;
+          pWin->eStart = aUp[i].eStart;
+          pWin->eEnd = aUp[i].eEnd;
+          pWin->eExclude = 0;
+          if( pWin->eStart==TK_FOLLOWING ){
+            pWin->pStart = sqlite3Expr(db, TK_INTEGER, "1");
+          }
+          break;
+        }
+      }
+    }
+  }
+  pWin->pWFunc = pFunc;
+}
+
+/*
+** Context object passed through sqlite3WalkExprList() to
+** selectWindowRewriteExprCb() by selectWindowRewriteEList().
+*/
+typedef struct WindowRewrite WindowRewrite;
+struct WindowRewrite {
+  Window *pWin;
+  SrcList *pSrc;
+  ExprList *pSub;
+  Table *pTab;
+  Select *pSubSelect;             /* Current sub-select, if any */
+};
+
+/*
+** Callback function used by selectWindowRewriteEList(). If necessary,
+** this function appends to the output expression-list and updates
+** expression (*ppExpr) in place.
+*/
+static int selectWindowRewriteExprCb(Walker *pWalker, Expr *pExpr){
+  struct WindowRewrite *p = pWalker->u.pRewrite;
+  Parse *pParse = pWalker->pParse;
+  assert( p!=0 );
+  assert( p->pWin!=0 );
+
+  /* If this function is being called from within a scalar sub-select
+  ** that used by the SELECT statement being processed, only process
+  ** TK_COLUMN expressions that refer to it (the outer SELECT). Do
+  ** not process aggregates or window functions at all, as they belong
+  ** to the scalar sub-select.  */
+  if( p->pSubSelect ){
+    if( pExpr->op!=TK_COLUMN ){
+      return WRC_Continue;
+    }else{
+      int nSrc = p->pSrc->nSrc;
+      int i;
+      for(i=0; i<nSrc; i++){
+        if( pExpr->iTable==p->pSrc->a[i].iCursor ) break;
+      }
+      if( i==nSrc ) return WRC_Continue;
+    }
+  }
+
+  switch( pExpr->op ){
+
+    case TK_FUNCTION:
+      if( !ExprHasProperty(pExpr, EP_WinFunc) ){
+        break;
+      }else{
+        Window *pWin;
+        for(pWin=p->pWin; pWin; pWin=pWin->pNextWin){
+          if( pExpr->y.pWin==pWin ){
+            assert( pWin->pOwner==pExpr );
+            return WRC_Prune;
+          }
+        }
+      }
+      /* no break */ deliberate_fall_through
+
+    case TK_IF_NULL_ROW:
+    case TK_AGG_FUNCTION:
+    case TK_COLUMN: {
+      int iCol = -1;
+      if( pParse->db->mallocFailed ) return WRC_Abort;
+      if( p->pSub ){
+        int i;
+        for(i=0; i<p->pSub->nExpr; i++){
+          if( 0==sqlite3ExprCompare(0, p->pSub->a[i].pExpr, pExpr, -1) ){
+            iCol = i;
+            break;
+          }
+        }
+      }
+      if( iCol<0 ){
+        Expr *pDup = sqlite3ExprDup(pParse->db, pExpr, 0);
+        if( pDup && pDup->op==TK_AGG_FUNCTION ) pDup->op = TK_FUNCTION;
+        p->pSub = sqlite3ExprListAppend(pParse, p->pSub, pDup);
+      }
+      if( p->pSub ){
+        int f = pExpr->flags & EP_Collate;
+        assert( ExprHasProperty(pExpr, EP_Static)==0 );
+        ExprSetProperty(pExpr, EP_Static);
+        sqlite3ExprDelete(pParse->db, pExpr);
+        ExprClearProperty(pExpr, EP_Static);
+        memset(pExpr, 0, sizeof(Expr));
+
+        pExpr->op = TK_COLUMN;
+        pExpr->iColumn = (iCol<0 ? p->pSub->nExpr-1: iCol);
+        pExpr->iTable = p->pWin->iEphCsr;
+        pExpr->y.pTab = p->pTab;
+        pExpr->flags = f;
+      }
+      if( pParse->db->mallocFailed ) return WRC_Abort;
+      break;
+    }
+
+    default: /* no-op */
+      break;
+  }
+
+  return WRC_Continue;
+}
+static int selectWindowRewriteSelectCb(Walker *pWalker, Select *pSelect){
+  struct WindowRewrite *p = pWalker->u.pRewrite;
+  Select *pSave = p->pSubSelect;
+  if( pSave==pSelect ){
+    return WRC_Continue;
+  }else{
+    p->pSubSelect = pSelect;
+    sqlite3WalkSelect(pWalker, pSelect);
+    p->pSubSelect = pSave;
+  }
+  return WRC_Prune;
+}
+
+
+/*
+** Iterate through each expression in expression-list pEList. For each:
+**
+**   * TK_COLUMN,
+**   * aggregate function, or
+**   * window function with a Window object that is not a member of the
+**     Window list passed as the second argument (pWin).
+**
+** Append the node to output expression-list (*ppSub). And replace it
+** with a TK_COLUMN that reads the (N-1)th element of table
+** pWin->iEphCsr, where N is the number of elements in (*ppSub) after
+** appending the new one.
+*/
+static void selectWindowRewriteEList(
+  Parse *pParse,
+  Window *pWin,
+  SrcList *pSrc,
+  ExprList *pEList,               /* Rewrite expressions in this list */
+  Table *pTab,
+  ExprList **ppSub                /* IN/OUT: Sub-select expression-list */
+){
+  Walker sWalker;
+  WindowRewrite sRewrite;
+
+  assert( pWin!=0 );
+  memset(&sWalker, 0, sizeof(Walker));
+  memset(&sRewrite, 0, sizeof(WindowRewrite));
+
+  sRewrite.pSub = *ppSub;
+  sRewrite.pWin = pWin;
+  sRewrite.pSrc = pSrc;
+  sRewrite.pTab = pTab;
+
+  sWalker.pParse = pParse;
+  sWalker.xExprCallback = selectWindowRewriteExprCb;
+  sWalker.xSelectCallback = selectWindowRewriteSelectCb;
+  sWalker.u.pRewrite = &sRewrite;
+
+  (void)sqlite3WalkExprList(&sWalker, pEList);
+
+  *ppSub = sRewrite.pSub;
+}
+
+/*
+** Append a copy of each expression in expression-list pAppend to
+** expression list pList. Return a pointer to the result list.
+*/
+static ExprList *exprListAppendList(
+  Parse *pParse,          /* Parsing context */
+  ExprList *pList,        /* List to which to append. Might be NULL */
+  ExprList *pAppend,      /* List of values to append. Might be NULL */
+  int bIntToNull
+){
+  if( pAppend ){
+    int i;
+    int nInit = pList ? pList->nExpr : 0;
+    for(i=0; i<pAppend->nExpr; i++){
+      sqlite3 *db = pParse->db;
+      Expr *pDup = sqlite3ExprDup(db, pAppend->a[i].pExpr, 0);
+      if( db->mallocFailed ){
+        sqlite3ExprDelete(db, pDup);
+        break;
+      }
+      if( bIntToNull ){
+        int iDummy;
+        Expr *pSub;
+        pSub = sqlite3ExprSkipCollateAndLikely(pDup);
+        if( sqlite3ExprIsInteger(pSub, &iDummy, 0) ){
+          pSub->op = TK_NULL;
+          pSub->flags &= ~(EP_IntValue|EP_IsTrue|EP_IsFalse);
+          pSub->u.zToken = 0;
+        }
+      }
+      pList = sqlite3ExprListAppend(pParse, pList, pDup);
+      if( pList ) pList->a[nInit+i].fg.sortFlags = pAppend->a[i].fg.sortFlags;
+    }
+  }
+  return pList;
+}
+
+/*
+** When rewriting a query, if the new subquery in the FROM clause
+** contains TK_AGG_FUNCTION nodes that refer to an outer query,
+** then we have to increase the Expr->op2 values of those nodes
+** due to the extra subquery layer that was added.
+**
+** See also the incrAggDepth() routine in resolve.c
+*/
+static int sqlite3WindowExtraAggFuncDepth(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_AGG_FUNCTION
+   && pExpr->op2>=pWalker->walkerDepth
+  ){
+    pExpr->op2++;
+  }
+  return WRC_Continue;
+}
+
+static int disallowAggregatesInOrderByCb(Walker *pWalker, Expr *pExpr){
+  if( pExpr->op==TK_AGG_FUNCTION && pExpr->pAggInfo==0 ){
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+     sqlite3ErrorMsg(pWalker->pParse,
+         "misuse of aggregate: %s()", pExpr->u.zToken);
+  }
+  return WRC_Continue;
+}
+
+/*
+** If the SELECT statement passed as the second argument does not invoke
+** any SQL window functions, this function is a no-op. Otherwise, it
+** rewrites the SELECT statement so that window function xStep functions
+** are invoked in the correct order as described under "SELECT REWRITING"
+** at the top of this file.
+*/
+SQLITE_PRIVATE int sqlite3WindowRewrite(Parse *pParse, Select *p){
+  int rc = SQLITE_OK;
+  if( p->pWin
+   && p->pPrior==0
+   && ALWAYS((p->selFlags & SF_WinRewrite)==0)
+   && ALWAYS(!IN_RENAME_OBJECT)
+  ){
+    Vdbe *v = sqlite3GetVdbe(pParse);
+    sqlite3 *db = pParse->db;
+    Select *pSub = 0;             /* The subquery */
+    SrcList *pSrc = p->pSrc;
+    Expr *pWhere = p->pWhere;
+    ExprList *pGroupBy = p->pGroupBy;
+    Expr *pHaving = p->pHaving;
+    ExprList *pSort = 0;
+
+    ExprList *pSublist = 0;       /* Expression list for sub-query */
+    Window *pMWin = p->pWin;      /* Main window object */
+    Window *pWin;                 /* Window object iterator */
+    Table *pTab;
+    Walker w;
+
+    u32 selFlags = p->selFlags;
+
+    pTab = sqlite3DbMallocZero(db, sizeof(Table));
+    if( pTab==0 ){
+      return sqlite3ErrorToParser(db, SQLITE_NOMEM);
+    }
+    sqlite3AggInfoPersistWalkerInit(&w, pParse);
+    sqlite3WalkSelect(&w, p);
+    if( (p->selFlags & SF_Aggregate)==0 ){
+      w.xExprCallback = disallowAggregatesInOrderByCb;
+      w.xSelectCallback = 0;
+      sqlite3WalkExprList(&w, p->pOrderBy);
+    }
+
+    p->pSrc = 0;
+    p->pWhere = 0;
+    p->pGroupBy = 0;
+    p->pHaving = 0;
+    p->selFlags &= ~SF_Aggregate;
+    p->selFlags |= SF_WinRewrite;
+
+    /* Create the ORDER BY clause for the sub-select. This is the concatenation
+    ** of the window PARTITION and ORDER BY clauses. Then, if this makes it
+    ** redundant, remove the ORDER BY from the parent SELECT.  */
+    pSort = exprListAppendList(pParse, 0, pMWin->pPartition, 1);
+    pSort = exprListAppendList(pParse, pSort, pMWin->pOrderBy, 1);
+    if( pSort && p->pOrderBy && p->pOrderBy->nExpr<=pSort->nExpr ){
+      int nSave = pSort->nExpr;
+      pSort->nExpr = p->pOrderBy->nExpr;
+      if( sqlite3ExprListCompare(pSort, p->pOrderBy, -1)==0 ){
+        sqlite3ExprListDelete(db, p->pOrderBy);
+        p->pOrderBy = 0;
+      }
+      pSort->nExpr = nSave;
+    }
+
+    /* Assign a cursor number for the ephemeral table used to buffer rows.
+    ** The OpenEphemeral instruction is coded later, after it is known how
+    ** many columns the table will have.  */
+    pMWin->iEphCsr = pParse->nTab++;
+    pParse->nTab += 3;
+
+    selectWindowRewriteEList(pParse, pMWin, pSrc, p->pEList, pTab, &pSublist);
+    selectWindowRewriteEList(pParse, pMWin, pSrc, p->pOrderBy, pTab, &pSublist);
+    pMWin->nBufferCol = (pSublist ? pSublist->nExpr : 0);
+
+    /* Append the PARTITION BY and ORDER BY expressions to the to the
+    ** sub-select expression list. They are required to figure out where
+    ** boundaries for partitions and sets of peer rows lie.  */
+    pSublist = exprListAppendList(pParse, pSublist, pMWin->pPartition, 0);
+    pSublist = exprListAppendList(pParse, pSublist, pMWin->pOrderBy, 0);
+
+    /* Append the arguments passed to each window function to the
+    ** sub-select expression list. Also allocate two registers for each
+    ** window function - one for the accumulator, another for interim
+    ** results.  */
+    for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+      ExprList *pArgs;
+      assert( ExprUseXList(pWin->pOwner) );
+      assert( pWin->pWFunc!=0 );
+      pArgs = pWin->pOwner->x.pList;
+      if( pWin->pWFunc->funcFlags & SQLITE_SUBTYPE ){
+        selectWindowRewriteEList(pParse, pMWin, pSrc, pArgs, pTab, &pSublist);
+        pWin->iArgCol = (pSublist ? pSublist->nExpr : 0);
+        pWin->bExprArgs = 1;
+      }else{
+        pWin->iArgCol = (pSublist ? pSublist->nExpr : 0);
+        pSublist = exprListAppendList(pParse, pSublist, pArgs, 0);
+      }
+      if( pWin->pFilter ){
+        Expr *pFilter = sqlite3ExprDup(db, pWin->pFilter, 0);
+        pSublist = sqlite3ExprListAppend(pParse, pSublist, pFilter);
+      }
+      pWin->regAccum = ++pParse->nMem;
+      pWin->regResult = ++pParse->nMem;
+      sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
+    }
+
+    /* If there is no ORDER BY or PARTITION BY clause, and the window
+    ** function accepts zero arguments, and there are no other columns
+    ** selected (e.g. "SELECT row_number() OVER () FROM t1"), it is possible
+    ** that pSublist is still NULL here. Add a constant expression here to
+    ** keep everything legal in this case.
+    */
+    if( pSublist==0 ){
+      pSublist = sqlite3ExprListAppend(pParse, 0,
+        sqlite3Expr(db, TK_INTEGER, "0")
+      );
+    }
+
+    pSub = sqlite3SelectNew(
+        pParse, pSublist, pSrc, pWhere, pGroupBy, pHaving, pSort, 0, 0
+    );
+    TREETRACE(0x40,pParse,pSub,
+       ("New window-function subquery in FROM clause of (%u/%p)\n",
+       p->selId, p));
+    p->pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
+    assert( pSub!=0 || p->pSrc==0 ); /* Due to db->mallocFailed test inside
+                                     ** of sqlite3DbMallocRawNN() called from
+                                     ** sqlite3SrcListAppend() */
+    if( p->pSrc==0 ){
+      sqlite3SelectDelete(db, pSub);
+    }else if( sqlite3SrcItemAttachSubquery(pParse, &p->pSrc->a[0], pSub, 0) ){
+      Table *pTab2;
+      p->pSrc->a[0].fg.isCorrelated = 1;
+      sqlite3SrcListAssignCursors(pParse, p->pSrc);
+      pSub->selFlags |= SF_Expanded|SF_OrderByReqd;
+      pTab2 = sqlite3ResultSetOfSelect(pParse, pSub, SQLITE_AFF_NONE);
+      pSub->selFlags |= (selFlags & SF_Aggregate);
+      if( pTab2==0 ){
+        /* Might actually be some other kind of error, but in that case
+        ** pParse->nErr will be set, so if SQLITE_NOMEM is set, we will get
+        ** the correct error message regardless. */
+        rc = SQLITE_NOMEM;
+      }else{
+        memcpy(pTab, pTab2, sizeof(Table));
+        pTab->tabFlags |= TF_Ephemeral;
+        p->pSrc->a[0].pSTab = pTab;
+        pTab = pTab2;
+        memset(&w, 0, sizeof(w));
+        w.xExprCallback = sqlite3WindowExtraAggFuncDepth;
+        w.xSelectCallback = sqlite3WalkerDepthIncrease;
+        w.xSelectCallback2 = sqlite3WalkerDepthDecrease;
+        sqlite3WalkSelect(&w, pSub);
+      }
+    }
+    if( db->mallocFailed ) rc = SQLITE_NOMEM;
+
+    /* Defer deleting the temporary table pTab because if an error occurred,
+    ** there could still be references to that table embedded in the
+    ** result-set or ORDER BY clause of the SELECT statement p.  */
+    sqlite3ParserAddCleanup(pParse, sqlite3DbFree, pTab);
+  }
+
+  assert( rc==SQLITE_OK || pParse->nErr!=0 );
+  return rc;
+}
+
+/*
+** Unlink the Window object from the Select to which it is attached,
+** if it is attached.
+*/
+SQLITE_PRIVATE void sqlite3WindowUnlinkFromSelect(Window *p){
+  if( p->ppThis ){
+    *p->ppThis = p->pNextWin;
+    if( p->pNextWin ) p->pNextWin->ppThis = p->ppThis;
+    p->ppThis = 0;
+  }
+}
+
+/*
+** Free the Window object passed as the second argument.
+*/
+SQLITE_PRIVATE void sqlite3WindowDelete(sqlite3 *db, Window *p){
+  if( p ){
+    sqlite3WindowUnlinkFromSelect(p);
+    sqlite3ExprDelete(db, p->pFilter);
+    sqlite3ExprListDelete(db, p->pPartition);
+    sqlite3ExprListDelete(db, p->pOrderBy);
+    sqlite3ExprDelete(db, p->pEnd);
+    sqlite3ExprDelete(db, p->pStart);
+    sqlite3DbFree(db, p->zName);
+    sqlite3DbFree(db, p->zBase);
+    sqlite3DbFree(db, p);
+  }
+}
+
+/*
+** Free the linked list of Window objects starting at the second argument.
+*/
+SQLITE_PRIVATE void sqlite3WindowListDelete(sqlite3 *db, Window *p){
+  while( p ){
+    Window *pNext = p->pNextWin;
+    sqlite3WindowDelete(db, p);
+    p = pNext;
+  }
+}
+
+/*
+** The argument expression is an PRECEDING or FOLLOWING offset.  The
+** value should be a non-negative integer.  If the value is not a
+** constant, change it to NULL.  The fact that it is then a non-negative
+** integer will be caught later.  But it is important not to leave
+** variable values in the expression tree.
+*/
+static Expr *sqlite3WindowOffsetExpr(Parse *pParse, Expr *pExpr){
+  if( 0==sqlite3ExprIsConstant(0,pExpr) ){
+    if( IN_RENAME_OBJECT ) sqlite3RenameExprUnmap(pParse, pExpr);
+    sqlite3ExprDelete(pParse->db, pExpr);
+    pExpr = sqlite3ExprAlloc(pParse->db, TK_NULL, 0, 0);
+  }
+  return pExpr;
+}
+
+/*
+** Allocate and return a new Window object describing a Window Definition.
+*/
+SQLITE_PRIVATE Window *sqlite3WindowAlloc(
+  Parse *pParse,    /* Parsing context */
+  int eType,        /* Frame type. TK_RANGE, TK_ROWS, TK_GROUPS, or 0 */
+  int eStart,       /* Start type: CURRENT, PRECEDING, FOLLOWING, UNBOUNDED */
+  Expr *pStart,     /* Start window size if TK_PRECEDING or FOLLOWING */
+  int eEnd,         /* End type: CURRENT, FOLLOWING, TK_UNBOUNDED, PRECEDING */
+  Expr *pEnd,       /* End window size if TK_FOLLOWING or PRECEDING */
+  u8 eExclude       /* EXCLUDE clause */
+){
+  Window *pWin = 0;
+  int bImplicitFrame = 0;
+
+  /* Parser assures the following: */
+  assert( eType==0 || eType==TK_RANGE || eType==TK_ROWS || eType==TK_GROUPS );
+  assert( eStart==TK_CURRENT || eStart==TK_PRECEDING
+           || eStart==TK_UNBOUNDED || eStart==TK_FOLLOWING );
+  assert( eEnd==TK_CURRENT || eEnd==TK_FOLLOWING
+           || eEnd==TK_UNBOUNDED || eEnd==TK_PRECEDING );
+  assert( (eStart==TK_PRECEDING || eStart==TK_FOLLOWING)==(pStart!=0) );
+  assert( (eEnd==TK_FOLLOWING || eEnd==TK_PRECEDING)==(pEnd!=0) );
+
+  if( eType==0 ){
+    bImplicitFrame = 1;
+    eType = TK_RANGE;
+  }
+
+  /* Additionally, the
+  ** starting boundary type may not occur earlier in the following list than
+  ** the ending boundary type:
+  **
+  **   UNBOUNDED PRECEDING
+  **   <expr> PRECEDING
+  **   CURRENT ROW
+  **   <expr> FOLLOWING
+  **   UNBOUNDED FOLLOWING
+  **
+  ** The parser ensures that "UNBOUNDED PRECEDING" cannot be used as an ending
+  ** boundary, and than "UNBOUNDED FOLLOWING" cannot be used as a starting
+  ** frame boundary.
+  */
+  if( (eStart==TK_CURRENT && eEnd==TK_PRECEDING)
+   || (eStart==TK_FOLLOWING && (eEnd==TK_PRECEDING || eEnd==TK_CURRENT))
+  ){
+    sqlite3ErrorMsg(pParse, "unsupported frame specification");
+    goto windowAllocErr;
+  }
+
+  pWin = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
+  if( pWin==0 ) goto windowAllocErr;
+  pWin->eFrmType = eType;
+  pWin->eStart = eStart;
+  pWin->eEnd = eEnd;
+  if( eExclude==0 && OptimizationDisabled(pParse->db, SQLITE_WindowFunc) ){
+    eExclude = TK_NO;
+  }
+  pWin->eExclude = eExclude;
+  pWin->bImplicitFrame = bImplicitFrame;
+  pWin->pEnd = sqlite3WindowOffsetExpr(pParse, pEnd);
+  pWin->pStart = sqlite3WindowOffsetExpr(pParse, pStart);
+  return pWin;
+
+windowAllocErr:
+  sqlite3ExprDelete(pParse->db, pEnd);
+  sqlite3ExprDelete(pParse->db, pStart);
+  return 0;
+}
+
+/*
+** Attach PARTITION and ORDER BY clauses pPartition and pOrderBy to window
+** pWin. Also, if parameter pBase is not NULL, set pWin->zBase to the
+** equivalent nul-terminated string.
+*/
+SQLITE_PRIVATE Window *sqlite3WindowAssemble(
+  Parse *pParse,
+  Window *pWin,
+  ExprList *pPartition,
+  ExprList *pOrderBy,
+  Token *pBase
+){
+  if( pWin ){
+    pWin->pPartition = pPartition;
+    pWin->pOrderBy = pOrderBy;
+    if( pBase ){
+      pWin->zBase = sqlite3DbStrNDup(pParse->db, pBase->z, pBase->n);
+    }
+  }else{
+    sqlite3ExprListDelete(pParse->db, pPartition);
+    sqlite3ExprListDelete(pParse->db, pOrderBy);
+  }
+  return pWin;
+}
+
+/*
+** Window *pWin has just been created from a WINDOW clause. Token pBase
+** is the base window. Earlier windows from the same WINDOW clause are
+** stored in the linked list starting at pWin->pNextWin. This function
+** either updates *pWin according to the base specification, or else
+** leaves an error in pParse.
+*/
+SQLITE_PRIVATE void sqlite3WindowChain(Parse *pParse, Window *pWin, Window *pList){
+  if( pWin->zBase ){
+    sqlite3 *db = pParse->db;
+    Window *pExist = windowFind(pParse, pList, pWin->zBase);
+    if( pExist ){
+      const char *zErr = 0;
+      /* Check for errors */
+      if( pWin->pPartition ){
+        zErr = "PARTITION clause";
+      }else if( pExist->pOrderBy && pWin->pOrderBy ){
+        zErr = "ORDER BY clause";
+      }else if( pExist->bImplicitFrame==0 ){
+        zErr = "frame specification";
+      }
+      if( zErr ){
+        sqlite3ErrorMsg(pParse,
+            "cannot override %s of window: %s", zErr, pWin->zBase
+        );
+      }else{
+        pWin->pPartition = sqlite3ExprListDup(db, pExist->pPartition, 0);
+        if( pExist->pOrderBy ){
+          assert( pWin->pOrderBy==0 );
+          pWin->pOrderBy = sqlite3ExprListDup(db, pExist->pOrderBy, 0);
+        }
+        sqlite3DbFree(db, pWin->zBase);
+        pWin->zBase = 0;
+      }
+    }
+  }
+}
+
+/*
+** Attach window object pWin to expression p.
+*/
+SQLITE_PRIVATE void sqlite3WindowAttach(Parse *pParse, Expr *p, Window *pWin){
+  if( p ){
+    assert( p->op==TK_FUNCTION );
+    assert( pWin );
+    assert( ExprIsFullSize(p) );
+    p->y.pWin = pWin;
+    ExprSetProperty(p, EP_WinFunc|EP_FullSize);
+    pWin->pOwner = p;
+    if( (p->flags & EP_Distinct) && pWin->eFrmType!=TK_FILTER ){
+      sqlite3ErrorMsg(pParse,
+          "DISTINCT is not supported for window functions"
+      );
+    }
+  }else{
+    sqlite3WindowDelete(pParse->db, pWin);
+  }
+}
+
+/*
+** Possibly link window pWin into the list at pSel->pWin (window functions
+** to be processed as part of SELECT statement pSel). The window is linked
+** in if either (a) there are no other windows already linked to this
+** SELECT, or (b) the windows already linked use a compatible window frame.
+*/
+SQLITE_PRIVATE void sqlite3WindowLink(Select *pSel, Window *pWin){
+  if( pSel ){
+    if( 0==pSel->pWin || 0==sqlite3WindowCompare(0, pSel->pWin, pWin, 0) ){
+      pWin->pNextWin = pSel->pWin;
+      if( pSel->pWin ){
+        pSel->pWin->ppThis = &pWin->pNextWin;
+      }
+      pSel->pWin = pWin;
+      pWin->ppThis = &pSel->pWin;
+    }else{
+      if( sqlite3ExprListCompare(pWin->pPartition, pSel->pWin->pPartition,-1) ){
+        pSel->selFlags |= SF_MultiPart;
+      }
+    }
+  }
+}
+
+/*
+** Return 0 if the two window objects are identical, 1 if they are
+** different, or 2 if it cannot be determined if the objects are identical
+** or not. Identical window objects can be processed in a single scan.
+*/
+SQLITE_PRIVATE int sqlite3WindowCompare(
+  const Parse *pParse,
+  const Window *p1,
+  const Window *p2,
+  int bFilter
+){
+  int res;
+  if( NEVER(p1==0) || NEVER(p2==0) ) return 1;
+  if( p1->eFrmType!=p2->eFrmType ) return 1;
+  if( p1->eStart!=p2->eStart ) return 1;
+  if( p1->eEnd!=p2->eEnd ) return 1;
+  if( p1->eExclude!=p2->eExclude ) return 1;
+  if( sqlite3ExprCompare(pParse, p1->pStart, p2->pStart, -1) ) return 1;
+  if( sqlite3ExprCompare(pParse, p1->pEnd, p2->pEnd, -1) ) return 1;
+  if( (res = sqlite3ExprListCompare(p1->pPartition, p2->pPartition, -1)) ){
+    return res;
+  }
+  if( (res = sqlite3ExprListCompare(p1->pOrderBy, p2->pOrderBy, -1)) ){
+    return res;
+  }
+  if( bFilter ){
+    if( (res = sqlite3ExprCompare(pParse, p1->pFilter, p2->pFilter, -1)) ){
+      return res;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** This is called by code in select.c before it calls sqlite3WhereBegin()
+** to begin iterating through the sub-query results. It is used to allocate
+** and initialize registers and cursors used by sqlite3WindowCodeStep().
+*/
+SQLITE_PRIVATE void sqlite3WindowCodeInit(Parse *pParse, Select *pSelect){
+  Window *pWin;
+  int nEphExpr;
+  Window *pMWin;
+  Vdbe *v;
+
+  assert( pSelect->pSrc->a[0].fg.isSubquery );
+  nEphExpr = pSelect->pSrc->a[0].u4.pSubq->pSelect->pEList->nExpr;
+  pMWin = pSelect->pWin;
+  v = sqlite3GetVdbe(pParse);
+
+  sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pMWin->iEphCsr, nEphExpr);
+  sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+1, pMWin->iEphCsr);
+  sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+2, pMWin->iEphCsr);
+  sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+3, pMWin->iEphCsr);
+
+  /* Allocate registers to use for PARTITION BY values, if any. Initialize
+  ** said registers to NULL.  */
+  if( pMWin->pPartition ){
+    int nExpr = pMWin->pPartition->nExpr;
+    pMWin->regPart = pParse->nMem+1;
+    pParse->nMem += nExpr;
+    sqlite3VdbeAddOp3(v, OP_Null, 0, pMWin->regPart, pMWin->regPart+nExpr-1);
+  }
+
+  pMWin->regOne = ++pParse->nMem;
+  sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regOne);
+
+  if( pMWin->eExclude ){
+    pMWin->regStartRowid = ++pParse->nMem;
+    pMWin->regEndRowid = ++pParse->nMem;
+    pMWin->csrApp = pParse->nTab++;
+    sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regStartRowid);
+    sqlite3VdbeAddOp2(v, OP_Integer, 0, pMWin->regEndRowid);
+    sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->csrApp, pMWin->iEphCsr);
+    return;
+  }
+
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    FuncDef *p = pWin->pWFunc;
+    if( (p->funcFlags & SQLITE_FUNC_MINMAX) && pWin->eStart!=TK_UNBOUNDED ){
+      /* The inline versions of min() and max() require a single ephemeral
+      ** table and 3 registers. The registers are used as follows:
+      **
+      **   regApp+0: slot to copy min()/max() argument to for MakeRecord
+      **   regApp+1: integer value used to ensure keys are unique
+      **   regApp+2: output of MakeRecord
+      */
+      ExprList *pList;
+      KeyInfo *pKeyInfo;
+      assert( ExprUseXList(pWin->pOwner) );
+      pList = pWin->pOwner->x.pList;
+      pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pList, 0, 0);
+      pWin->csrApp = pParse->nTab++;
+      pWin->regApp = pParse->nMem+1;
+      pParse->nMem += 3;
+      if( pKeyInfo && pWin->pWFunc->zName[1]=='i' ){
+        assert( pKeyInfo->aSortFlags[0]==0 );
+        pKeyInfo->aSortFlags[0] = KEYINFO_ORDER_DESC;
+      }
+      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pWin->csrApp, 2);
+      sqlite3VdbeAppendP4(v, pKeyInfo, P4_KEYINFO);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1);
+    }
+    else if( p->zName==nth_valueName || p->zName==first_valueName ){
+      /* Allocate two registers at pWin->regApp. These will be used to
+      ** store the start and end index of the current frame.  */
+      pWin->regApp = pParse->nMem+1;
+      pWin->csrApp = pParse->nTab++;
+      pParse->nMem += 2;
+      sqlite3VdbeAddOp2(v, OP_OpenDup, pWin->csrApp, pMWin->iEphCsr);
+    }
+    else if( p->zName==leadName || p->zName==lagName ){
+      pWin->csrApp = pParse->nTab++;
+      sqlite3VdbeAddOp2(v, OP_OpenDup, pWin->csrApp, pMWin->iEphCsr);
+    }
+  }
+}
+
+#define WINDOW_STARTING_INT  0
+#define WINDOW_ENDING_INT    1
+#define WINDOW_NTH_VALUE_INT 2
+#define WINDOW_STARTING_NUM  3
+#define WINDOW_ENDING_NUM    4
+
+/*
+** A "PRECEDING <expr>" (eCond==0) or "FOLLOWING <expr>" (eCond==1) or the
+** value of the second argument to nth_value() (eCond==2) has just been
+** evaluated and the result left in register reg. This function generates VM
+** code to check that the value is a non-negative integer and throws an
+** exception if it is not.
+*/
+static void windowCheckValue(Parse *pParse, int reg, int eCond){
+  static const char *azErr[] = {
+    "frame starting offset must be a non-negative integer",
+    "frame ending offset must be a non-negative integer",
+    "second argument to nth_value must be a positive integer",
+    "frame starting offset must be a non-negative number",
+    "frame ending offset must be a non-negative number",
+  };
+  static int aOp[] = { OP_Ge, OP_Ge, OP_Gt, OP_Ge, OP_Ge };
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int regZero = sqlite3GetTempReg(pParse);
+  assert( eCond>=0 && eCond<ArraySize(azErr) );
+  sqlite3VdbeAddOp2(v, OP_Integer, 0, regZero);
+  if( eCond>=WINDOW_STARTING_NUM ){
+    int regString = sqlite3GetTempReg(pParse);
+    sqlite3VdbeAddOp4(v, OP_String8, 0, regString, 0, "", P4_STATIC);
+    sqlite3VdbeAddOp3(v, OP_Ge, regString, sqlite3VdbeCurrentAddr(v)+2, reg);
+    sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC|SQLITE_JUMPIFNULL);
+    VdbeCoverage(v);
+    assert( eCond==3 || eCond==4 );
+    VdbeCoverageIf(v, eCond==3);
+    VdbeCoverageIf(v, eCond==4);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_MustBeInt, reg, sqlite3VdbeCurrentAddr(v)+2);
+    VdbeCoverage(v);
+    assert( eCond==0 || eCond==1 || eCond==2 );
+    VdbeCoverageIf(v, eCond==0);
+    VdbeCoverageIf(v, eCond==1);
+    VdbeCoverageIf(v, eCond==2);
+  }
+  sqlite3VdbeAddOp3(v, aOp[eCond], regZero, sqlite3VdbeCurrentAddr(v)+2, reg);
+  sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC);
+  VdbeCoverageNeverNullIf(v, eCond==0); /* NULL case captured by */
+  VdbeCoverageNeverNullIf(v, eCond==1); /*   the OP_MustBeInt */
+  VdbeCoverageNeverNullIf(v, eCond==2);
+  VdbeCoverageNeverNullIf(v, eCond==3); /* NULL case caught by */
+  VdbeCoverageNeverNullIf(v, eCond==4); /*   the OP_Ge */
+  sqlite3MayAbort(pParse);
+  sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_ERROR, OE_Abort);
+  sqlite3VdbeAppendP4(v, (void*)azErr[eCond], P4_STATIC);
+  sqlite3ReleaseTempReg(pParse, regZero);
+}
+
+/*
+** Return the number of arguments passed to the window-function associated
+** with the object passed as the only argument to this function.
+*/
+static int windowArgCount(Window *pWin){
+  const ExprList *pList;
+  assert( ExprUseXList(pWin->pOwner) );
+  pList = pWin->pOwner->x.pList;
+  return (pList ? pList->nExpr : 0);
+}
+
+typedef struct WindowCodeArg WindowCodeArg;
+typedef struct WindowCsrAndReg WindowCsrAndReg;
+
+/*
+** See comments above struct WindowCodeArg.
+*/
+struct WindowCsrAndReg {
+  int csr;                        /* Cursor number */
+  int reg;                        /* First in array of peer values */
+};
+
+/*
+** A single instance of this structure is allocated on the stack by
+** sqlite3WindowCodeStep() and a pointer to it passed to the various helper
+** routines. This is to reduce the number of arguments required by each
+** helper function.
+**
+** regArg:
+**   Each window function requires an accumulator register (just as an
+**   ordinary aggregate function does). This variable is set to the first
+**   in an array of accumulator registers - one for each window function
+**   in the WindowCodeArg.pMWin list.
+**
+** eDelete:
+**   The window functions implementation sometimes caches the input rows
+**   that it processes in a temporary table. If it is not zero, this
+**   variable indicates when rows may be removed from the temp table (in
+**   order to reduce memory requirements - it would always be safe just
+**   to leave them there). Possible values for eDelete are:
+**
+**      WINDOW_RETURN_ROW:
+**        An input row can be discarded after it is returned to the caller.
+**
+**      WINDOW_AGGINVERSE:
+**        An input row can be discarded after the window functions xInverse()
+**        callbacks have been invoked in it.
+**
+**      WINDOW_AGGSTEP:
+**        An input row can be discarded after the window functions xStep()
+**        callbacks have been invoked in it.
+**
+** start,current,end
+**   Consider a window-frame similar to the following:
+**
+**     (ORDER BY a, b GROUPS BETWEEN 2 PRECEDING AND 2 FOLLOWING)
+**
+**   The windows functions implementation caches the input rows in a temp
+**   table, sorted by "a, b" (it actually populates the cache lazily, and
+**   aggressively removes rows once they are no longer required, but that's
+**   a mere detail). It keeps three cursors open on the temp table. One
+**   (current) that points to the next row to return to the query engine
+**   once its window function values have been calculated. Another (end)
+**   points to the next row to call the xStep() method of each window function
+**   on (so that it is 2 groups ahead of current). And a third (start) that
+**   points to the next row to call the xInverse() method of each window
+**   function on.
+**
+**   Each cursor (start, current and end) consists of a VDBE cursor
+**   (WindowCsrAndReg.csr) and an array of registers (starting at
+**   WindowCodeArg.reg) that always contains a copy of the peer values
+**   read from the corresponding cursor.
+**
+**   Depending on the window-frame in question, all three cursors may not
+**   be required. In this case both WindowCodeArg.csr and reg are set to
+**   0.
+*/
+struct WindowCodeArg {
+  Parse *pParse;             /* Parse context */
+  Window *pMWin;             /* First in list of functions being processed */
+  Vdbe *pVdbe;               /* VDBE object */
+  int addrGosub;             /* OP_Gosub to this address to return one row */
+  int regGosub;              /* Register used with OP_Gosub(addrGosub) */
+  int regArg;                /* First in array of accumulator registers */
+  int eDelete;               /* See above */
+  int regRowid;
+
+  WindowCsrAndReg start;
+  WindowCsrAndReg current;
+  WindowCsrAndReg end;
+};
+
+/*
+** Generate VM code to read the window frames peer values from cursor csr into
+** an array of registers starting at reg.
+*/
+static void windowReadPeerValues(
+  WindowCodeArg *p,
+  int csr,
+  int reg
+){
+  Window *pMWin = p->pMWin;
+  ExprList *pOrderBy = pMWin->pOrderBy;
+  if( pOrderBy ){
+    Vdbe *v = sqlite3GetVdbe(p->pParse);
+    ExprList *pPart = pMWin->pPartition;
+    int iColOff = pMWin->nBufferCol + (pPart ? pPart->nExpr : 0);
+    int i;
+    for(i=0; i<pOrderBy->nExpr; i++){
+      sqlite3VdbeAddOp3(v, OP_Column, csr, iColOff+i, reg+i);
+    }
+  }
+}
+
+/*
+** Generate VM code to invoke either xStep() (if bInverse is 0) or
+** xInverse (if bInverse is non-zero) for each window function in the
+** linked list starting at pMWin. Or, for built-in window functions
+** that do not use the standard function API, generate the required
+** inline VM code.
+**
+** If argument csr is greater than or equal to 0, then argument reg is
+** the first register in an array of registers guaranteed to be large
+** enough to hold the array of arguments for each function. In this case
+** the arguments are extracted from the current row of csr into the
+** array of registers before invoking OP_AggStep or OP_AggInverse
+**
+** Or, if csr is less than zero, then the array of registers at reg is
+** already populated with all columns from the current row of the sub-query.
+**
+** If argument regPartSize is non-zero, then it is a register containing the
+** number of rows in the current partition.
+*/
+static void windowAggStep(
+  WindowCodeArg *p,
+  Window *pMWin,                  /* Linked list of window functions */
+  int csr,                        /* Read arguments from this cursor */
+  int bInverse,                   /* True to invoke xInverse instead of xStep */
+  int reg                         /* Array of registers */
+){
+  Parse *pParse = p->pParse;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  Window *pWin;
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    FuncDef *pFunc = pWin->pWFunc;
+    int regArg;
+    int nArg = pWin->bExprArgs ? 0 : windowArgCount(pWin);
+    int i;
+    int addrIf = 0;
+
+    assert( bInverse==0 || pWin->eStart!=TK_UNBOUNDED );
+
+    /* All OVER clauses in the same window function aggregate step must
+    ** be the same. */
+    assert( pWin==pMWin || sqlite3WindowCompare(pParse,pWin,pMWin,0)!=1 );
+
+    for(i=0; i<nArg; i++){
+      if( i!=1 || pFunc->zName!=nth_valueName ){
+        sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+i, reg+i);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_Column, pMWin->iEphCsr, pWin->iArgCol+i, reg+i);
+      }
+    }
+    regArg = reg;
+
+    if( pWin->pFilter ){
+      int regTmp;
+      assert( ExprUseXList(pWin->pOwner) );
+      assert( pWin->bExprArgs || !nArg ||nArg==pWin->pOwner->x.pList->nExpr );
+      assert( pWin->bExprArgs || nArg  ||pWin->pOwner->x.pList==0 );
+      regTmp = sqlite3GetTempReg(pParse);
+      sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+nArg,regTmp);
+      addrIf = sqlite3VdbeAddOp3(v, OP_IfNot, regTmp, 0, 1);
+      VdbeCoverage(v);
+      sqlite3ReleaseTempReg(pParse, regTmp);
+    }
+
+    if( pMWin->regStartRowid==0
+     && (pFunc->funcFlags & SQLITE_FUNC_MINMAX)
+     && (pWin->eStart!=TK_UNBOUNDED)
+    ){
+      int addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, regArg);
+      VdbeCoverage(v);
+      if( bInverse==0 ){
+        sqlite3VdbeAddOp2(v, OP_AddImm, pWin->regApp+1, 1);
+        sqlite3VdbeAddOp2(v, OP_SCopy, regArg, pWin->regApp);
+        sqlite3VdbeAddOp3(v, OP_MakeRecord, pWin->regApp, 2, pWin->regApp+2);
+        sqlite3VdbeAddOp2(v, OP_IdxInsert, pWin->csrApp, pWin->regApp+2);
+      }else{
+        sqlite3VdbeAddOp4Int(v, OP_SeekGE, pWin->csrApp, 0, regArg, 1);
+        VdbeCoverageNeverTaken(v);
+        sqlite3VdbeAddOp1(v, OP_Delete, pWin->csrApp);
+        sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
+      }
+      sqlite3VdbeJumpHere(v, addrIsNull);
+    }else if( pWin->regApp ){
+      assert( pWin->pFilter==0 );
+      assert( pFunc->zName==nth_valueName
+           || pFunc->zName==first_valueName
+      );
+      assert( bInverse==0 || bInverse==1 );
+      sqlite3VdbeAddOp2(v, OP_AddImm, pWin->regApp+1-bInverse, 1);
+    }else if( pFunc->xSFunc!=noopStepFunc ){
+      if( pWin->bExprArgs ){
+        int iOp = sqlite3VdbeCurrentAddr(v);
+        int iEnd;
+
+        assert( ExprUseXList(pWin->pOwner) );
+        nArg = pWin->pOwner->x.pList->nExpr;
+        regArg = sqlite3GetTempRange(pParse, nArg);
+        sqlite3ExprCodeExprList(pParse, pWin->pOwner->x.pList, regArg, 0, 0);
+
+        for(iEnd=sqlite3VdbeCurrentAddr(v); iOp<iEnd; iOp++){
+          VdbeOp *pOp = sqlite3VdbeGetOp(v, iOp);
+          if( pOp->opcode==OP_Column && pOp->p1==pMWin->iEphCsr ){
+            pOp->p1 = csr;
+          }
+        }
+      }
+      if( pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){
+        CollSeq *pColl;
+        assert( nArg>0 );
+        assert( ExprUseXList(pWin->pOwner) );
+        pColl = sqlite3ExprNNCollSeq(pParse, pWin->pOwner->x.pList->a[0].pExpr);
+        sqlite3VdbeAddOp4(v, OP_CollSeq, 0,0,0, (const char*)pColl, P4_COLLSEQ);
+      }
+      sqlite3VdbeAddOp3(v, bInverse? OP_AggInverse : OP_AggStep,
+                        bInverse, regArg, pWin->regAccum);
+      sqlite3VdbeAppendP4(v, pFunc, P4_FUNCDEF);
+      sqlite3VdbeChangeP5(v, (u16)nArg);
+      if( pWin->bExprArgs ){
+        sqlite3ReleaseTempRange(pParse, regArg, nArg);
+      }
+    }
+
+    if( addrIf ) sqlite3VdbeJumpHere(v, addrIf);
+  }
+}
+
+/*
+** Values that may be passed as the second argument to windowCodeOp().
+*/
+#define WINDOW_RETURN_ROW 1
+#define WINDOW_AGGINVERSE 2
+#define WINDOW_AGGSTEP    3
+
+/*
+** Generate VM code to invoke either xValue() (bFin==0) or xFinalize()
+** (bFin==1) for each window function in the linked list starting at
+** pMWin. Or, for built-in window-functions that do not use the standard
+** API, generate the equivalent VM code.
+*/
+static void windowAggFinal(WindowCodeArg *p, int bFin){
+  Parse *pParse = p->pParse;
+  Window *pMWin = p->pMWin;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  Window *pWin;
+
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    if( pMWin->regStartRowid==0
+     && (pWin->pWFunc->funcFlags & SQLITE_FUNC_MINMAX)
+     && (pWin->eStart!=TK_UNBOUNDED)
+    ){
+      sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult);
+      sqlite3VdbeAddOp1(v, OP_Last, pWin->csrApp);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_Column, pWin->csrApp, 0, pWin->regResult);
+      sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
+    }else if( pWin->regApp ){
+      assert( pMWin->regStartRowid==0 );
+    }else{
+      int nArg = windowArgCount(pWin);
+      if( bFin ){
+        sqlite3VdbeAddOp2(v, OP_AggFinal, pWin->regAccum, nArg);
+        sqlite3VdbeAppendP4(v, pWin->pWFunc, P4_FUNCDEF);
+        sqlite3VdbeAddOp2(v, OP_Copy, pWin->regAccum, pWin->regResult);
+        sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
+      }else{
+        sqlite3VdbeAddOp3(v, OP_AggValue,pWin->regAccum,nArg,pWin->regResult);
+        sqlite3VdbeAppendP4(v, pWin->pWFunc, P4_FUNCDEF);
+      }
+    }
+  }
+}
+
+/*
+** Generate code to calculate the current values of all window functions in the
+** p->pMWin list by doing a full scan of the current window frame. Store the
+** results in the Window.regResult registers, ready to return the upper
+** layer.
+*/
+static void windowFullScan(WindowCodeArg *p){
+  Window *pWin;
+  Parse *pParse = p->pParse;
+  Window *pMWin = p->pMWin;
+  Vdbe *v = p->pVdbe;
+
+  int regCRowid = 0;              /* Current rowid value */
+  int regCPeer = 0;               /* Current peer values */
+  int regRowid = 0;               /* AggStep rowid value */
+  int regPeer = 0;                /* AggStep peer values */
+
+  int nPeer;
+  int lblNext;
+  int lblBrk;
+  int addrNext;
+  int csr;
+
+  VdbeModuleComment((v, "windowFullScan begin"));
+
+  assert( pMWin!=0 );
+  csr = pMWin->csrApp;
+  nPeer = (pMWin->pOrderBy ? pMWin->pOrderBy->nExpr : 0);
+
+  lblNext = sqlite3VdbeMakeLabel(pParse);
+  lblBrk = sqlite3VdbeMakeLabel(pParse);
+
+  regCRowid = sqlite3GetTempReg(pParse);
+  regRowid = sqlite3GetTempReg(pParse);
+  if( nPeer ){
+    regCPeer = sqlite3GetTempRange(pParse, nPeer);
+    regPeer = sqlite3GetTempRange(pParse, nPeer);
+  }
+
+  sqlite3VdbeAddOp2(v, OP_Rowid, pMWin->iEphCsr, regCRowid);
+  windowReadPeerValues(p, pMWin->iEphCsr, regCPeer);
+
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
+  }
+
+  sqlite3VdbeAddOp3(v, OP_SeekGE, csr, lblBrk, pMWin->regStartRowid);
+  VdbeCoverage(v);
+  addrNext = sqlite3VdbeCurrentAddr(v);
+  sqlite3VdbeAddOp2(v, OP_Rowid, csr, regRowid);
+  sqlite3VdbeAddOp3(v, OP_Gt, pMWin->regEndRowid, lblBrk, regRowid);
+  VdbeCoverageNeverNull(v);
+
+  if( pMWin->eExclude==TK_CURRENT ){
+    sqlite3VdbeAddOp3(v, OP_Eq, regCRowid, lblNext, regRowid);
+    VdbeCoverageNeverNull(v);
+  }else if( pMWin->eExclude!=TK_NO ){
+    int addr;
+    int addrEq = 0;
+    KeyInfo *pKeyInfo = 0;
+
+    if( pMWin->pOrderBy ){
+      pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pMWin->pOrderBy, 0, 0);
+    }
+    if( pMWin->eExclude==TK_TIES ){
+      addrEq = sqlite3VdbeAddOp3(v, OP_Eq, regCRowid, 0, regRowid);
+      VdbeCoverageNeverNull(v);
+    }
+    if( pKeyInfo ){
+      windowReadPeerValues(p, csr, regPeer);
+      sqlite3VdbeAddOp3(v, OP_Compare, regPeer, regCPeer, nPeer);
+      sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
+      addr = sqlite3VdbeCurrentAddr(v)+1;
+      sqlite3VdbeAddOp3(v, OP_Jump, addr, lblNext, addr);
+      VdbeCoverageEqNe(v);
+    }else{
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, lblNext);
+    }
+    if( addrEq ) sqlite3VdbeJumpHere(v, addrEq);
+  }
+
+  windowAggStep(p, pMWin, csr, 0, p->regArg);
+
+  sqlite3VdbeResolveLabel(v, lblNext);
+  sqlite3VdbeAddOp2(v, OP_Next, csr, addrNext);
+  VdbeCoverage(v);
+  sqlite3VdbeJumpHere(v, addrNext-1);
+  sqlite3VdbeJumpHere(v, addrNext+1);
+  sqlite3ReleaseTempReg(pParse, regRowid);
+  sqlite3ReleaseTempReg(pParse, regCRowid);
+  if( nPeer ){
+    sqlite3ReleaseTempRange(pParse, regPeer, nPeer);
+    sqlite3ReleaseTempRange(pParse, regCPeer, nPeer);
+  }
+
+  windowAggFinal(p, 1);
+  VdbeModuleComment((v, "windowFullScan end"));
+}
+
+/*
+** Invoke the sub-routine at regGosub (generated by code in select.c) to
+** return the current row of Window.iEphCsr. If all window functions are
+** aggregate window functions that use the standard API, a single
+** OP_Gosub instruction is all that this routine generates. Extra VM code
+** for per-row processing is only generated for the following built-in window
+** functions:
+**
+**   nth_value()
+**   first_value()
+**   lag()
+**   lead()
+*/
+static void windowReturnOneRow(WindowCodeArg *p){
+  Window *pMWin = p->pMWin;
+  Vdbe *v = p->pVdbe;
+
+  if( pMWin->regStartRowid ){
+    windowFullScan(p);
+  }else{
+    Parse *pParse = p->pParse;
+    Window *pWin;
+
+    for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+      FuncDef *pFunc = pWin->pWFunc;
+      assert( ExprUseXList(pWin->pOwner) );
+      if( pFunc->zName==nth_valueName
+       || pFunc->zName==first_valueName
+      ){
+        int csr = pWin->csrApp;
+        int lbl = sqlite3VdbeMakeLabel(pParse);
+        int tmpReg = sqlite3GetTempReg(pParse);
+        sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult);
+
+        if( pFunc->zName==nth_valueName ){
+          sqlite3VdbeAddOp3(v, OP_Column,pMWin->iEphCsr,pWin->iArgCol+1,tmpReg);
+          windowCheckValue(pParse, tmpReg, 2);
+        }else{
+          sqlite3VdbeAddOp2(v, OP_Integer, 1, tmpReg);
+        }
+        sqlite3VdbeAddOp3(v, OP_Add, tmpReg, pWin->regApp, tmpReg);
+        sqlite3VdbeAddOp3(v, OP_Gt, pWin->regApp+1, lbl, tmpReg);
+        VdbeCoverageNeverNull(v);
+        sqlite3VdbeAddOp3(v, OP_SeekRowid, csr, 0, tmpReg);
+        VdbeCoverageNeverTaken(v);
+        sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol, pWin->regResult);
+        sqlite3VdbeResolveLabel(v, lbl);
+        sqlite3ReleaseTempReg(pParse, tmpReg);
+      }
+      else if( pFunc->zName==leadName || pFunc->zName==lagName ){
+        int nArg = pWin->pOwner->x.pList->nExpr;
+        int csr = pWin->csrApp;
+        int lbl = sqlite3VdbeMakeLabel(pParse);
+        int tmpReg = sqlite3GetTempReg(pParse);
+        int iEph = pMWin->iEphCsr;
+
+        if( nArg<3 ){
+          sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult);
+        }else{
+          sqlite3VdbeAddOp3(v, OP_Column, iEph,pWin->iArgCol+2,pWin->regResult);
+        }
+        sqlite3VdbeAddOp2(v, OP_Rowid, iEph, tmpReg);
+        if( nArg<2 ){
+          int val = (pFunc->zName==leadName ? 1 : -1);
+          sqlite3VdbeAddOp2(v, OP_AddImm, tmpReg, val);
+        }else{
+          int op = (pFunc->zName==leadName ? OP_Add : OP_Subtract);
+          int tmpReg2 = sqlite3GetTempReg(pParse);
+          sqlite3VdbeAddOp3(v, OP_Column, iEph, pWin->iArgCol+1, tmpReg2);
+          sqlite3VdbeAddOp3(v, op, tmpReg2, tmpReg, tmpReg);
+          sqlite3ReleaseTempReg(pParse, tmpReg2);
+        }
+
+        sqlite3VdbeAddOp3(v, OP_SeekRowid, csr, lbl, tmpReg);
+        VdbeCoverage(v);
+        sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol, pWin->regResult);
+        sqlite3VdbeResolveLabel(v, lbl);
+        sqlite3ReleaseTempReg(pParse, tmpReg);
+      }
+    }
+  }
+  sqlite3VdbeAddOp2(v, OP_Gosub, p->regGosub, p->addrGosub);
+}
+
+/*
+** Generate code to set the accumulator register for each window function
+** in the linked list passed as the second argument to NULL. And perform
+** any equivalent initialization required by any built-in window functions
+** in the list.
+*/
+static int windowInitAccum(Parse *pParse, Window *pMWin){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int regArg;
+  int nArg = 0;
+  Window *pWin;
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    FuncDef *pFunc = pWin->pWFunc;
+    assert( pWin->regAccum );
+    sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
+    nArg = MAX(nArg, windowArgCount(pWin));
+    if( pMWin->regStartRowid==0 ){
+      if( pFunc->zName==nth_valueName || pFunc->zName==first_valueName ){
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp);
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1);
+      }
+
+      if( (pFunc->funcFlags & SQLITE_FUNC_MINMAX) && pWin->csrApp ){
+        assert( pWin->eStart!=TK_UNBOUNDED );
+        sqlite3VdbeAddOp1(v, OP_ResetSorter, pWin->csrApp);
+        sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1);
+      }
+    }
+  }
+  regArg = pParse->nMem+1;
+  pParse->nMem += nArg;
+  return regArg;
+}
+
+/*
+** Return true if the current frame should be cached in the ephemeral table,
+** even if there are no xInverse() calls required.
+*/
+static int windowCacheFrame(Window *pMWin){
+  Window *pWin;
+  if( pMWin->regStartRowid ) return 1;
+  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
+    FuncDef *pFunc = pWin->pWFunc;
+    if( (pFunc->zName==nth_valueName)
+     || (pFunc->zName==first_valueName)
+     || (pFunc->zName==leadName)
+     || (pFunc->zName==lagName)
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** regOld and regNew are each the first register in an array of size
+** pOrderBy->nExpr. This function generates code to compare the two
+** arrays of registers using the collation sequences and other comparison
+** parameters specified by pOrderBy.
+**
+** If the two arrays are not equal, the contents of regNew is copied to
+** regOld and control falls through. Otherwise, if the contents of the arrays
+** are equal, an OP_Goto is executed. The address of the OP_Goto is returned.
+*/
+static void windowIfNewPeer(
+  Parse *pParse,
+  ExprList *pOrderBy,
+  int regNew,                     /* First in array of new values */
+  int regOld,                     /* First in array of old values */
+  int addr                        /* Jump here */
+){
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  if( pOrderBy ){
+    int nVal = pOrderBy->nExpr;
+    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pOrderBy, 0, 0);
+    sqlite3VdbeAddOp3(v, OP_Compare, regOld, regNew, nVal);
+    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
+    sqlite3VdbeAddOp3(v, OP_Jump,
+      sqlite3VdbeCurrentAddr(v)+1, addr, sqlite3VdbeCurrentAddr(v)+1
+    );
+    VdbeCoverageEqNe(v);
+    sqlite3VdbeAddOp3(v, OP_Copy, regNew, regOld, nVal-1);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
+  }
+}
+
+/*
+** This function is called as part of generating VM programs for RANGE
+** offset PRECEDING/FOLLOWING frame boundaries. Assuming "ASC" order for
+** the ORDER BY term in the window, and that argument op is OP_Ge, it generates
+** code equivalent to:
+**
+**   if( csr1.peerVal + regVal >= csr2.peerVal ) goto lbl;
+**
+** The value of parameter op may also be OP_Gt or OP_Le. In these cases the
+** operator in the above pseudo-code is replaced with ">" or "<=", respectively.
+**
+** If the sort-order for the ORDER BY term in the window is DESC, then the
+** comparison is reversed. Instead of adding regVal to csr1.peerVal, it is
+** subtracted. And the comparison operator is inverted to - ">=" becomes "<=",
+** ">" becomes "<", and so on. So, with DESC sort order, if the argument op
+** is OP_Ge, the generated code is equivalent to:
+**
+**   if( csr1.peerVal - regVal <= csr2.peerVal ) goto lbl;
+**
+** A special type of arithmetic is used such that if csr1.peerVal is not
+** a numeric type (real or integer), then the result of the addition
+** or subtraction is a a copy of csr1.peerVal.
+*/
+static void windowCodeRangeTest(
+  WindowCodeArg *p,
+  int op,                         /* OP_Ge, OP_Gt, or OP_Le */
+  int csr1,                       /* Cursor number for cursor 1 */
+  int regVal,                     /* Register containing non-negative number */
+  int csr2,                       /* Cursor number for cursor 2 */
+  int lbl                         /* Jump destination if condition is true */
+){
+  Parse *pParse = p->pParse;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  ExprList *pOrderBy = p->pMWin->pOrderBy;  /* ORDER BY clause for window */
+  int reg1 = sqlite3GetTempReg(pParse);     /* Reg. for csr1.peerVal+regVal */
+  int reg2 = sqlite3GetTempReg(pParse);     /* Reg. for csr2.peerVal */
+  int regString = ++pParse->nMem;           /* Reg. for constant value '' */
+  int arith = OP_Add;                       /* OP_Add or OP_Subtract */
+  int addrGe;                               /* Jump destination */
+  int addrDone = sqlite3VdbeMakeLabel(pParse);   /* Address past OP_Ge */
+  CollSeq *pColl;
+
+  /* Read the peer-value from each cursor into a register */
+  windowReadPeerValues(p, csr1, reg1);
+  windowReadPeerValues(p, csr2, reg2);
+
+  assert( op==OP_Ge || op==OP_Gt || op==OP_Le );
+  assert( pOrderBy && pOrderBy->nExpr==1 );
+  if( pOrderBy->a[0].fg.sortFlags & KEYINFO_ORDER_DESC ){
+    switch( op ){
+      case OP_Ge: op = OP_Le; break;
+      case OP_Gt: op = OP_Lt; break;
+      default: assert( op==OP_Le ); op = OP_Ge; break;
+    }
+    arith = OP_Subtract;
+  }
+
+  VdbeModuleComment((v, "CodeRangeTest: if( R%d %s R%d %s R%d ) goto lbl",
+      reg1, (arith==OP_Add ? "+" : "-"), regVal,
+      ((op==OP_Ge) ? ">=" : (op==OP_Le) ? "<=" : (op==OP_Gt) ? ">" : "<"), reg2
+  ));
+
+  /* If the BIGNULL flag is set for the ORDER BY, then it is required to
+  ** consider NULL values to be larger than all other values, instead of
+  ** the usual smaller. The VDBE opcodes OP_Ge and so on do not handle this
+  ** (and adding that capability causes a performance regression), so
+  ** instead if the BIGNULL flag is set then cases where either reg1 or
+  ** reg2 are NULL are handled separately in the following block. The code
+  ** generated is equivalent to:
+  **
+  **   if( reg1 IS NULL ){
+  **     if( op==OP_Ge ) goto lbl;
+  **     if( op==OP_Gt && reg2 IS NOT NULL ) goto lbl;
+  **     if( op==OP_Le && reg2 IS NULL ) goto lbl;
+  **   }else if( reg2 IS NULL ){
+  **     if( op==OP_Le ) goto lbl;
+  **   }
+  **
+  ** Additionally, if either reg1 or reg2 are NULL but the jump to lbl is
+  ** not taken, control jumps over the comparison operator coded below this
+  ** block.  */
+  if( pOrderBy->a[0].fg.sortFlags & KEYINFO_ORDER_BIGNULL ){
+    /* This block runs if reg1 contains a NULL. */
+    int addr = sqlite3VdbeAddOp1(v, OP_NotNull, reg1); VdbeCoverage(v);
+    switch( op ){
+      case OP_Ge:
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, lbl);
+        break;
+      case OP_Gt:
+        sqlite3VdbeAddOp2(v, OP_NotNull, reg2, lbl);
+        VdbeCoverage(v);
+        break;
+      case OP_Le:
+        sqlite3VdbeAddOp2(v, OP_IsNull, reg2, lbl);
+        VdbeCoverage(v);
+        break;
+      default: assert( op==OP_Lt ); /* no-op */ break;
+    }
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrDone);
+
+    /* This block runs if reg1 is not NULL, but reg2 is. */
+    sqlite3VdbeJumpHere(v, addr);
+    sqlite3VdbeAddOp2(v, OP_IsNull, reg2,
+                      (op==OP_Gt || op==OP_Ge) ? addrDone : lbl);
+    VdbeCoverage(v);
+  }
+
+  /* Register reg1 currently contains csr1.peerVal (the peer-value from csr1).
+  ** This block adds (or subtracts for DESC) the numeric value in regVal
+  ** from it. Or, if reg1 is not numeric (it is a NULL, a text value or a blob),
+  ** then leave reg1 as it is. In pseudo-code, this is implemented as:
+  **
+  **   if( reg1>='' ) goto addrGe;
+  **   reg1 = reg1 +/- regVal
+  **   addrGe:
+  **
+  ** Since all strings and blobs are greater-than-or-equal-to an empty string,
+  ** the add/subtract is skipped for these, as required. If reg1 is a NULL,
+  ** then the arithmetic is performed, but since adding or subtracting from
+  ** NULL is always NULL anyway, this case is handled as required too.  */
+  sqlite3VdbeAddOp4(v, OP_String8, 0, regString, 0, "", P4_STATIC);
+  addrGe = sqlite3VdbeAddOp3(v, OP_Ge, regString, 0, reg1);
+  VdbeCoverage(v);
+  if( (op==OP_Ge && arith==OP_Add) || (op==OP_Le && arith==OP_Subtract) ){
+    sqlite3VdbeAddOp3(v, op, reg2, lbl, reg1); VdbeCoverage(v);
+  }
+  sqlite3VdbeAddOp3(v, arith, regVal, reg1, reg1);
+  sqlite3VdbeJumpHere(v, addrGe);
+
+  /* Compare registers reg2 and reg1, taking the jump if required. Note that
+  ** control skips over this test if the BIGNULL flag is set and either
+  ** reg1 or reg2 contain a NULL value.  */
+  sqlite3VdbeAddOp3(v, op, reg2, lbl, reg1); VdbeCoverage(v);
+  pColl = sqlite3ExprNNCollSeq(pParse, pOrderBy->a[0].pExpr);
+  sqlite3VdbeAppendP4(v, (void*)pColl, P4_COLLSEQ);
+  sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
+  sqlite3VdbeResolveLabel(v, addrDone);
+
+  assert( op==OP_Ge || op==OP_Gt || op==OP_Lt || op==OP_Le );
+  testcase(op==OP_Ge); VdbeCoverageIf(v, op==OP_Ge);
+  testcase(op==OP_Lt); VdbeCoverageIf(v, op==OP_Lt);
+  testcase(op==OP_Le); VdbeCoverageIf(v, op==OP_Le);
+  testcase(op==OP_Gt); VdbeCoverageIf(v, op==OP_Gt);
+  sqlite3ReleaseTempReg(pParse, reg1);
+  sqlite3ReleaseTempReg(pParse, reg2);
+
+  VdbeModuleComment((v, "CodeRangeTest: end"));
+}
+
+/*
+** Helper function for sqlite3WindowCodeStep(). Each call to this function
+** generates VM code for a single RETURN_ROW, AGGSTEP or AGGINVERSE
+** operation. Refer to the header comment for sqlite3WindowCodeStep() for
+** details.
+*/
+static int windowCodeOp(
+ WindowCodeArg *p,                /* Context object */
+ int op,                          /* WINDOW_RETURN_ROW, AGGSTEP or AGGINVERSE */
+ int regCountdown,                /* Register for OP_IfPos countdown */
+ int jumpOnEof                    /* Jump here if stepped cursor reaches EOF */
+){
+  int csr, reg;
+  Parse *pParse = p->pParse;
+  Window *pMWin = p->pMWin;
+  int ret = 0;
+  Vdbe *v = p->pVdbe;
+  int addrContinue = 0;
+  int bPeer = (pMWin->eFrmType!=TK_ROWS);
+
+  int lblDone = sqlite3VdbeMakeLabel(pParse);
+  int addrNextRange = 0;
+
+  /* Special case - WINDOW_AGGINVERSE is always a no-op if the frame
+  ** starts with UNBOUNDED PRECEDING. */
+  if( op==WINDOW_AGGINVERSE && pMWin->eStart==TK_UNBOUNDED ){
+    assert( regCountdown==0 && jumpOnEof==0 );
+    return 0;
+  }
+
+  if( regCountdown>0 ){
+    if( pMWin->eFrmType==TK_RANGE ){
+      addrNextRange = sqlite3VdbeCurrentAddr(v);
+      assert( op==WINDOW_AGGINVERSE || op==WINDOW_AGGSTEP );
+      if( op==WINDOW_AGGINVERSE ){
+        if( pMWin->eStart==TK_FOLLOWING ){
+          windowCodeRangeTest(
+              p, OP_Le, p->current.csr, regCountdown, p->start.csr, lblDone
+          );
+        }else{
+          windowCodeRangeTest(
+              p, OP_Ge, p->start.csr, regCountdown, p->current.csr, lblDone
+          );
+        }
+      }else{
+        windowCodeRangeTest(
+            p, OP_Gt, p->end.csr, regCountdown, p->current.csr, lblDone
+        );
+      }
+    }else{
+      sqlite3VdbeAddOp3(v, OP_IfPos, regCountdown, lblDone, 1);
+      VdbeCoverage(v);
+    }
+  }
+
+  if( op==WINDOW_RETURN_ROW && pMWin->regStartRowid==0 ){
+    windowAggFinal(p, 0);
+  }
+  addrContinue = sqlite3VdbeCurrentAddr(v);
+
+  /* If this is a (RANGE BETWEEN a FOLLOWING AND b FOLLOWING) or
+  ** (RANGE BETWEEN b PRECEDING AND a PRECEDING) frame, ensure the
+  ** start cursor does not advance past the end cursor within the
+  ** temporary table. It otherwise might, if (a>b). Also ensure that,
+  ** if the input cursor is still finding new rows, that the end
+  ** cursor does not go past it to EOF. */
+  if( pMWin->eStart==pMWin->eEnd && regCountdown
+   && pMWin->eFrmType==TK_RANGE
+  ){
+    int regRowid1 = sqlite3GetTempReg(pParse);
+    int regRowid2 = sqlite3GetTempReg(pParse);
+    if( op==WINDOW_AGGINVERSE ){
+      sqlite3VdbeAddOp2(v, OP_Rowid, p->start.csr, regRowid1);
+      sqlite3VdbeAddOp2(v, OP_Rowid, p->end.csr, regRowid2);
+      sqlite3VdbeAddOp3(v, OP_Ge, regRowid2, lblDone, regRowid1);
+      VdbeCoverage(v);
+    }else if( p->regRowid ){
+      sqlite3VdbeAddOp2(v, OP_Rowid, p->end.csr, regRowid1);
+      sqlite3VdbeAddOp3(v, OP_Ge, p->regRowid, lblDone, regRowid1);
+      VdbeCoverageNeverNull(v);
+    }
+    sqlite3ReleaseTempReg(pParse, regRowid1);
+    sqlite3ReleaseTempReg(pParse, regRowid2);
+    assert( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_FOLLOWING );
+  }
+
+  switch( op ){
+    case WINDOW_RETURN_ROW:
+      csr = p->current.csr;
+      reg = p->current.reg;
+      windowReturnOneRow(p);
+      break;
+
+    case WINDOW_AGGINVERSE:
+      csr = p->start.csr;
+      reg = p->start.reg;
+      if( pMWin->regStartRowid ){
+        assert( pMWin->regEndRowid );
+        sqlite3VdbeAddOp2(v, OP_AddImm, pMWin->regStartRowid, 1);
+      }else{
+        windowAggStep(p, pMWin, csr, 1, p->regArg);
+      }
+      break;
+
+    default:
+      assert( op==WINDOW_AGGSTEP );
+      csr = p->end.csr;
+      reg = p->end.reg;
+      if( pMWin->regStartRowid ){
+        assert( pMWin->regEndRowid );
+        sqlite3VdbeAddOp2(v, OP_AddImm, pMWin->regEndRowid, 1);
+      }else{
+        windowAggStep(p, pMWin, csr, 0, p->regArg);
+      }
+      break;
+  }
+
+  if( op==p->eDelete ){
+    sqlite3VdbeAddOp1(v, OP_Delete, csr);
+    sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION);
+  }
+
+  if( jumpOnEof ){
+    sqlite3VdbeAddOp2(v, OP_Next, csr, sqlite3VdbeCurrentAddr(v)+2);
+    VdbeCoverage(v);
+    ret = sqlite3VdbeAddOp0(v, OP_Goto);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Next, csr, sqlite3VdbeCurrentAddr(v)+1+bPeer);
+    VdbeCoverage(v);
+    if( bPeer ){
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, lblDone);
+    }
+  }
+
+  if( bPeer ){
+    int nReg = (pMWin->pOrderBy ? pMWin->pOrderBy->nExpr : 0);
+    int regTmp = (nReg ? sqlite3GetTempRange(pParse, nReg) : 0);
+    windowReadPeerValues(p, csr, regTmp);
+    windowIfNewPeer(pParse, pMWin->pOrderBy, regTmp, reg, addrContinue);
+    sqlite3ReleaseTempRange(pParse, regTmp, nReg);
+  }
+
+  if( addrNextRange ){
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrNextRange);
+  }
+  sqlite3VdbeResolveLabel(v, lblDone);
+  return ret;
+}
+
+
+/*
+** Allocate and return a duplicate of the Window object indicated by the
+** third argument. Set the Window.pOwner field of the new object to
+** pOwner.
+*/
+SQLITE_PRIVATE Window *sqlite3WindowDup(sqlite3 *db, Expr *pOwner, Window *p){
+  Window *pNew = 0;
+  if( ALWAYS(p) ){
+    pNew = sqlite3DbMallocZero(db, sizeof(Window));
+    if( pNew ){
+      pNew->zName = sqlite3DbStrDup(db, p->zName);
+      pNew->zBase = sqlite3DbStrDup(db, p->zBase);
+      pNew->pFilter = sqlite3ExprDup(db, p->pFilter, 0);
+      pNew->pWFunc = p->pWFunc;
+      pNew->pPartition = sqlite3ExprListDup(db, p->pPartition, 0);
+      pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy, 0);
+      pNew->eFrmType = p->eFrmType;
+      pNew->eEnd = p->eEnd;
+      pNew->eStart = p->eStart;
+      pNew->eExclude = p->eExclude;
+      pNew->regResult = p->regResult;
+      pNew->regAccum = p->regAccum;
+      pNew->iArgCol = p->iArgCol;
+      pNew->iEphCsr = p->iEphCsr;
+      pNew->bExprArgs = p->bExprArgs;
+      pNew->pStart = sqlite3ExprDup(db, p->pStart, 0);
+      pNew->pEnd = sqlite3ExprDup(db, p->pEnd, 0);
+      pNew->pOwner = pOwner;
+      pNew->bImplicitFrame = p->bImplicitFrame;
+    }
+  }
+  return pNew;
+}
+
+/*
+** Return a copy of the linked list of Window objects passed as the
+** second argument.
+*/
+SQLITE_PRIVATE Window *sqlite3WindowListDup(sqlite3 *db, Window *p){
+  Window *pWin;
+  Window *pRet = 0;
+  Window **pp = &pRet;
+
+  for(pWin=p; pWin; pWin=pWin->pNextWin){
+    *pp = sqlite3WindowDup(db, 0, pWin);
+    if( *pp==0 ) break;
+    pp = &((*pp)->pNextWin);
+  }
+
+  return pRet;
+}
+
+/*
+** Return true if it can be determined at compile time that expression
+** pExpr evaluates to a value that, when cast to an integer, is greater
+** than zero. False otherwise.
+**
+** If an OOM error occurs, this function sets the Parse.db.mallocFailed
+** flag and returns zero.
+*/
+static int windowExprGtZero(Parse *pParse, Expr *pExpr){
+  int ret = 0;
+  sqlite3 *db = pParse->db;
+  sqlite3_value *pVal = 0;
+  sqlite3ValueFromExpr(db, pExpr, db->enc, SQLITE_AFF_NUMERIC, &pVal);
+  if( pVal && sqlite3_value_int(pVal)>0 ){
+    ret = 1;
+  }
+  sqlite3ValueFree(pVal);
+  return ret;
+}
+
+/*
+** sqlite3WhereBegin() has already been called for the SELECT statement
+** passed as the second argument when this function is invoked. It generates
+** code to populate the Window.regResult register for each window function
+** and invoke the sub-routine at instruction addrGosub once for each row.
+** sqlite3WhereEnd() is always called before returning.
+**
+** This function handles several different types of window frames, which
+** require slightly different processing. The following pseudo code is
+** used to implement window frames of the form:
+**
+**   ROWS BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING
+**
+** Other window frame types use variants of the following:
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**
+**       if( first row of partition ){
+**         // Rewind three cursors, all open on the eph table.
+**         Rewind(csrEnd);
+**         Rewind(csrStart);
+**         Rewind(csrCurrent);
+**
+**         regEnd = <expr2>          // FOLLOWING expression
+**         regStart = <expr1>        // PRECEDING expression
+**       }else{
+**         // First time this branch is taken, the eph table contains two
+**         // rows. The first row in the partition, which all three cursors
+**         // currently point to, and the following row.
+**         AGGSTEP
+**         if( (regEnd--)<=0 ){
+**           RETURN_ROW
+**           if( (regStart--)<=0 ){
+**             AGGINVERSE
+**           }
+**         }
+**       }
+**     }
+**     flush:
+**       AGGSTEP
+**       while( 1 ){
+**         RETURN ROW
+**         if( csrCurrent is EOF ) break;
+**         if( (regStart--)<=0 ){
+**           AggInverse(csrStart)
+**           Next(csrStart)
+**         }
+**       }
+**
+** The pseudo-code above uses the following shorthand:
+**
+**   AGGSTEP:    invoke the aggregate xStep() function for each window function
+**               with arguments read from the current row of cursor csrEnd, then
+**               step cursor csrEnd forward one row (i.e. sqlite3BtreeNext()).
+**
+**   RETURN_ROW: return a row to the caller based on the contents of the
+**               current row of csrCurrent and the current state of all
+**               aggregates. Then step cursor csrCurrent forward one row.
+**
+**   AGGINVERSE: invoke the aggregate xInverse() function for each window
+**               functions with arguments read from the current row of cursor
+**               csrStart. Then step csrStart forward one row.
+**
+** There are two other ROWS window frames that are handled significantly
+** differently from the above - "BETWEEN <expr> PRECEDING AND <expr> PRECEDING"
+** and "BETWEEN <expr> FOLLOWING AND <expr> FOLLOWING". These are special
+** cases because they change the order in which the three cursors (csrStart,
+** csrCurrent and csrEnd) iterate through the ephemeral table. Cases that
+** use UNBOUNDED or CURRENT ROW are much simpler variations on one of these
+** three.
+**
+**   ROWS BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**       if( first row of partition ){
+**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**         regEnd = <expr2>
+**         regStart = <expr1>
+**       }else{
+**         if( (regEnd--)<=0 ){
+**           AGGSTEP
+**         }
+**         RETURN_ROW
+**         if( (regStart--)<=0 ){
+**           AGGINVERSE
+**         }
+**       }
+**     }
+**     flush:
+**       if( (regEnd--)<=0 ){
+**         AGGSTEP
+**       }
+**       RETURN_ROW
+**
+**
+**   ROWS BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**     if( new partition ){
+**       Gosub flush
+**     }
+**     Insert new row into eph table.
+**     if( first row of partition ){
+**       Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**       regEnd = <expr2>
+**       regStart = regEnd - <expr1>
+**     }else{
+**       AGGSTEP
+**       if( (regEnd--)<=0 ){
+**         RETURN_ROW
+**       }
+**       if( (regStart--)<=0 ){
+**         AGGINVERSE
+**       }
+**     }
+**   }
+**   flush:
+**     AGGSTEP
+**     while( 1 ){
+**       if( (regEnd--)<=0 ){
+**         RETURN_ROW
+**         if( eof ) break;
+**       }
+**       if( (regStart--)<=0 ){
+**         AGGINVERSE
+**         if( eof ) break
+**       }
+**     }
+**     while( !eof csrCurrent ){
+**       RETURN_ROW
+**     }
+**
+** For the most part, the patterns above are adapted to support UNBOUNDED by
+** assuming that it is equivalent to "infinity PRECEDING/FOLLOWING" and
+** CURRENT ROW by assuming that it is equivalent to "0 PRECEDING/FOLLOWING".
+** This is optimized of course - branches that will never be taken and
+** conditions that are always true are omitted from the VM code. The only
+** exceptional case is:
+**
+**   ROWS BETWEEN <expr1> FOLLOWING AND UNBOUNDED FOLLOWING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**     if( new partition ){
+**       Gosub flush
+**     }
+**     Insert new row into eph table.
+**     if( first row of partition ){
+**       Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**       regStart = <expr1>
+**     }else{
+**       AGGSTEP
+**     }
+**   }
+**   flush:
+**     AGGSTEP
+**     while( 1 ){
+**       if( (regStart--)<=0 ){
+**         AGGINVERSE
+**         if( eof ) break
+**       }
+**       RETURN_ROW
+**     }
+**     while( !eof csrCurrent ){
+**       RETURN_ROW
+**     }
+**
+** Also requiring special handling are the cases:
+**
+**   ROWS BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING
+**   ROWS BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING
+**
+** when (expr1 < expr2). This is detected at runtime, not by this function.
+** To handle this case, the pseudo-code programs depicted above are modified
+** slightly to be:
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**     if( new partition ){
+**       Gosub flush
+**     }
+**     Insert new row into eph table.
+**     if( first row of partition ){
+**       Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**       regEnd = <expr2>
+**       regStart = <expr1>
+**       if( regEnd < regStart ){
+**         RETURN_ROW
+**         delete eph table contents
+**         continue
+**       }
+**     ...
+**
+** The new "continue" statement in the above jumps to the next iteration
+** of the outer loop - the one started by sqlite3WhereBegin().
+**
+** The various GROUPS cases are implemented using the same patterns as
+** ROWS. The VM code is modified slightly so that:
+**
+**   1. The else branch in the main loop is only taken if the row just
+**      added to the ephemeral table is the start of a new group. In
+**      other words, it becomes:
+**
+**         ... loop started by sqlite3WhereBegin() ...
+**         if( new partition ){
+**           Gosub flush
+**         }
+**         Insert new row into eph table.
+**         if( first row of partition ){
+**           Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**           regEnd = <expr2>
+**           regStart = <expr1>
+**         }else if( new group ){
+**           ...
+**         }
+**       }
+**
+**   2. Instead of processing a single row, each RETURN_ROW, AGGSTEP or
+**      AGGINVERSE step processes the current row of the relevant cursor and
+**      all subsequent rows belonging to the same group.
+**
+** RANGE window frames are a little different again. As for GROUPS, the
+** main loop runs once per group only. And RETURN_ROW, AGGSTEP and AGGINVERSE
+** deal in groups instead of rows. As for ROWS and GROUPS, there are three
+** basic cases:
+**
+**   RANGE BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**       if( first row of partition ){
+**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**         regEnd = <expr2>
+**         regStart = <expr1>
+**       }else{
+**         AGGSTEP
+**         while( (csrCurrent.key + regEnd) < csrEnd.key ){
+**           RETURN_ROW
+**           while( csrStart.key + regStart) < csrCurrent.key ){
+**             AGGINVERSE
+**           }
+**         }
+**       }
+**     }
+**     flush:
+**       AGGSTEP
+**       while( 1 ){
+**         RETURN ROW
+**         if( csrCurrent is EOF ) break;
+**           while( csrStart.key + regStart) < csrCurrent.key ){
+**             AGGINVERSE
+**           }
+**         }
+**       }
+**
+** In the above notation, "csr.key" means the current value of the ORDER BY
+** expression (there is only ever 1 for a RANGE that uses an <expr> FOLLOWING
+** or <expr PRECEDING) read from cursor csr.
+**
+**   RANGE BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**       if( first row of partition ){
+**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**         regEnd = <expr2>
+**         regStart = <expr1>
+**       }else{
+**         while( (csrEnd.key + regEnd) <= csrCurrent.key ){
+**           AGGSTEP
+**         }
+**         while( (csrStart.key + regStart) < csrCurrent.key ){
+**           AGGINVERSE
+**         }
+**         RETURN_ROW
+**       }
+**     }
+**     flush:
+**       while( (csrEnd.key + regEnd) <= csrCurrent.key ){
+**         AGGSTEP
+**       }
+**       while( (csrStart.key + regStart) < csrCurrent.key ){
+**         AGGINVERSE
+**       }
+**       RETURN_ROW
+**
+**   RANGE BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING
+**
+**     ... loop started by sqlite3WhereBegin() ...
+**       if( new partition ){
+**         Gosub flush
+**       }
+**       Insert new row into eph table.
+**       if( first row of partition ){
+**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
+**         regEnd = <expr2>
+**         regStart = <expr1>
+**       }else{
+**         AGGSTEP
+**         while( (csrCurrent.key + regEnd) < csrEnd.key ){
+**           while( (csrCurrent.key + regStart) > csrStart.key ){
+**             AGGINVERSE
+**           }
+**           RETURN_ROW
+**         }
+**       }
+**     }
+**     flush:
+**       AGGSTEP
+**       while( 1 ){
+**         while( (csrCurrent.key + regStart) > csrStart.key ){
+**           AGGINVERSE
+**           if( eof ) break "while( 1 )" loop.
+**         }
+**         RETURN_ROW
+**       }
+**       while( !eof csrCurrent ){
+**         RETURN_ROW
+**       }
+**
+** The text above leaves out many details. Refer to the code and comments
+** below for a more complete picture.
+*/
+SQLITE_PRIVATE void sqlite3WindowCodeStep(
+  Parse *pParse,                  /* Parse context */
+  Select *p,                      /* Rewritten SELECT statement */
+  WhereInfo *pWInfo,              /* Context returned by sqlite3WhereBegin() */
+  int regGosub,                   /* Register for OP_Gosub */
+  int addrGosub                   /* OP_Gosub here to return each row */
+){
+  Window *pMWin = p->pWin;
+  ExprList *pOrderBy = pMWin->pOrderBy;
+  Vdbe *v = sqlite3GetVdbe(pParse);
+  int csrWrite;                   /* Cursor used to write to eph. table */
+  int csrInput = p->pSrc->a[0].iCursor;     /* Cursor of sub-select */
+  int nInput = p->pSrc->a[0].pSTab->nCol;   /* Number of cols returned by sub */
+  int iInput;                               /* To iterate through sub cols */
+  int addrNe;                     /* Address of OP_Ne */
+  int addrGosubFlush = 0;         /* Address of OP_Gosub to flush: */
+  int addrInteger = 0;            /* Address of OP_Integer */
+  int addrEmpty;                  /* Address of OP_Rewind in flush: */
+  int regNew;                     /* Array of registers holding new input row */
+  int regRecord;                  /* regNew array in record form */
+  int regNewPeer = 0;             /* Peer values for new row (part of regNew) */
+  int regPeer = 0;                /* Peer values for current row */
+  int regFlushPart = 0;           /* Register for "Gosub flush_partition" */
+  WindowCodeArg s;                /* Context object for sub-routines */
+  int lblWhereEnd;                /* Label just before sqlite3WhereEnd() code */
+  int regStart = 0;               /* Value of <expr> PRECEDING */
+  int regEnd = 0;                 /* Value of <expr> FOLLOWING */
+
+  assert( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_CURRENT
+       || pMWin->eStart==TK_FOLLOWING || pMWin->eStart==TK_UNBOUNDED
+  );
+  assert( pMWin->eEnd==TK_FOLLOWING || pMWin->eEnd==TK_CURRENT
+       || pMWin->eEnd==TK_UNBOUNDED || pMWin->eEnd==TK_PRECEDING
+  );
+  assert( pMWin->eExclude==0 || pMWin->eExclude==TK_CURRENT
+       || pMWin->eExclude==TK_GROUP || pMWin->eExclude==TK_TIES
+       || pMWin->eExclude==TK_NO
+  );
+
+  lblWhereEnd = sqlite3VdbeMakeLabel(pParse);
+
+  /* Fill in the context object */
+  memset(&s, 0, sizeof(WindowCodeArg));
+  s.pParse = pParse;
+  s.pMWin = pMWin;
+  s.pVdbe = v;
+  s.regGosub = regGosub;
+  s.addrGosub = addrGosub;
+  s.current.csr = pMWin->iEphCsr;
+  csrWrite = s.current.csr+1;
+  s.start.csr = s.current.csr+2;
+  s.end.csr = s.current.csr+3;
+
+  /* Figure out when rows may be deleted from the ephemeral table. There
+  ** are four options - they may never be deleted (eDelete==0), they may
+  ** be deleted as soon as they are no longer part of the window frame
+  ** (eDelete==WINDOW_AGGINVERSE), they may be deleted as after the row
+  ** has been returned to the caller (WINDOW_RETURN_ROW), or they may
+  ** be deleted after they enter the frame (WINDOW_AGGSTEP). */
+  switch( pMWin->eStart ){
+    case TK_FOLLOWING:
+      if( pMWin->eFrmType!=TK_RANGE
+       && windowExprGtZero(pParse, pMWin->pStart)
+      ){
+        s.eDelete = WINDOW_RETURN_ROW;
+      }
+      break;
+    case TK_UNBOUNDED:
+      if( windowCacheFrame(pMWin)==0 ){
+        if( pMWin->eEnd==TK_PRECEDING ){
+          if( pMWin->eFrmType!=TK_RANGE
+           && windowExprGtZero(pParse, pMWin->pEnd)
+          ){
+            s.eDelete = WINDOW_AGGSTEP;
+          }
+        }else{
+          s.eDelete = WINDOW_RETURN_ROW;
+        }
+      }
+      break;
+    default:
+      s.eDelete = WINDOW_AGGINVERSE;
+      break;
+  }
+
+  /* Allocate registers for the array of values from the sub-query, the
+  ** same values in record form, and the rowid used to insert said record
+  ** into the ephemeral table.  */
+  regNew = pParse->nMem+1;
+  pParse->nMem += nInput;
+  regRecord = ++pParse->nMem;
+  s.regRowid = ++pParse->nMem;
+
+  /* If the window frame contains an "<expr> PRECEDING" or "<expr> FOLLOWING"
+  ** clause, allocate registers to store the results of evaluating each
+  ** <expr>.  */
+  if( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_FOLLOWING ){
+    regStart = ++pParse->nMem;
+  }
+  if( pMWin->eEnd==TK_PRECEDING || pMWin->eEnd==TK_FOLLOWING ){
+    regEnd = ++pParse->nMem;
+  }
+
+  /* If this is not a "ROWS BETWEEN ..." frame, then allocate arrays of
+  ** registers to store copies of the ORDER BY expressions (peer values)
+  ** for the main loop, and for each cursor (start, current and end). */
+  if( pMWin->eFrmType!=TK_ROWS ){
+    int nPeer = (pOrderBy ? pOrderBy->nExpr : 0);
+    regNewPeer = regNew + pMWin->nBufferCol;
+    if( pMWin->pPartition ) regNewPeer += pMWin->pPartition->nExpr;
+    regPeer = pParse->nMem+1;       pParse->nMem += nPeer;
+    s.start.reg = pParse->nMem+1;   pParse->nMem += nPeer;
+    s.current.reg = pParse->nMem+1; pParse->nMem += nPeer;
+    s.end.reg = pParse->nMem+1;     pParse->nMem += nPeer;
+  }
+
+  /* Load the column values for the row returned by the sub-select
+  ** into an array of registers starting at regNew. Assemble them into
+  ** a record in register regRecord. */
+  for(iInput=0; iInput<nInput; iInput++){
+    sqlite3VdbeAddOp3(v, OP_Column, csrInput, iInput, regNew+iInput);
+  }
+  sqlite3VdbeAddOp3(v, OP_MakeRecord, regNew, nInput, regRecord);
+
+  /* An input row has just been read into an array of registers starting
+  ** at regNew. If the window has a PARTITION clause, this block generates
+  ** VM code to check if the input row is the start of a new partition.
+  ** If so, it does an OP_Gosub to an address to be filled in later. The
+  ** address of the OP_Gosub is stored in local variable addrGosubFlush. */
+  if( pMWin->pPartition ){
+    int addr;
+    ExprList *pPart = pMWin->pPartition;
+    int nPart = pPart->nExpr;
+    int regNewPart = regNew + pMWin->nBufferCol;
+    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);
+
+    regFlushPart = ++pParse->nMem;
+    addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart, nPart);
+    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
+    sqlite3VdbeAddOp3(v, OP_Jump, addr+2, addr+4, addr+2);
+    VdbeCoverageEqNe(v);
+    addrGosubFlush = sqlite3VdbeAddOp1(v, OP_Gosub, regFlushPart);
+    VdbeComment((v, "call flush_partition"));
+    sqlite3VdbeAddOp3(v, OP_Copy, regNewPart, pMWin->regPart, nPart-1);
+  }
+
+  /* Insert the new row into the ephemeral table */
+  sqlite3VdbeAddOp2(v, OP_NewRowid, csrWrite, s.regRowid);
+  sqlite3VdbeAddOp3(v, OP_Insert, csrWrite, regRecord, s.regRowid);
+  addrNe = sqlite3VdbeAddOp3(v, OP_Ne, pMWin->regOne, 0, s.regRowid);
+  VdbeCoverageNeverNull(v);
+
+  /* This block is run for the first row of each partition */
+  s.regArg = windowInitAccum(pParse, pMWin);
+
+  if( regStart ){
+    sqlite3ExprCode(pParse, pMWin->pStart, regStart);
+    windowCheckValue(pParse, regStart, 0 + (pMWin->eFrmType==TK_RANGE?3:0));
+  }
+  if( regEnd ){
+    sqlite3ExprCode(pParse, pMWin->pEnd, regEnd);
+    windowCheckValue(pParse, regEnd, 1 + (pMWin->eFrmType==TK_RANGE?3:0));
+  }
+
+  if( pMWin->eFrmType!=TK_RANGE && pMWin->eStart==pMWin->eEnd && regStart ){
+    int op = ((pMWin->eStart==TK_FOLLOWING) ? OP_Ge : OP_Le);
+    int addrGe = sqlite3VdbeAddOp3(v, op, regStart, 0, regEnd);
+    VdbeCoverageNeverNullIf(v, op==OP_Ge); /* NeverNull because bound <expr> */
+    VdbeCoverageNeverNullIf(v, op==OP_Le); /*   values previously checked */
+    windowAggFinal(&s, 0);
+    sqlite3VdbeAddOp1(v, OP_Rewind, s.current.csr);
+    windowReturnOneRow(&s);
+    sqlite3VdbeAddOp1(v, OP_ResetSorter, s.current.csr);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, lblWhereEnd);
+    sqlite3VdbeJumpHere(v, addrGe);
+  }
+  if( pMWin->eStart==TK_FOLLOWING && pMWin->eFrmType!=TK_RANGE && regEnd ){
+    assert( pMWin->eEnd==TK_FOLLOWING );
+    sqlite3VdbeAddOp3(v, OP_Subtract, regStart, regEnd, regStart);
+  }
+
+  if( pMWin->eStart!=TK_UNBOUNDED ){
+    sqlite3VdbeAddOp1(v, OP_Rewind, s.start.csr);
+  }
+  sqlite3VdbeAddOp1(v, OP_Rewind, s.current.csr);
+  sqlite3VdbeAddOp1(v, OP_Rewind, s.end.csr);
+  if( regPeer && pOrderBy ){
+    sqlite3VdbeAddOp3(v, OP_Copy, regNewPeer, regPeer, pOrderBy->nExpr-1);
+    sqlite3VdbeAddOp3(v, OP_Copy, regPeer, s.start.reg, pOrderBy->nExpr-1);
+    sqlite3VdbeAddOp3(v, OP_Copy, regPeer, s.current.reg, pOrderBy->nExpr-1);
+    sqlite3VdbeAddOp3(v, OP_Copy, regPeer, s.end.reg, pOrderBy->nExpr-1);
+  }
+
+  sqlite3VdbeAddOp2(v, OP_Goto, 0, lblWhereEnd);
+
+  sqlite3VdbeJumpHere(v, addrNe);
+
+  /* Beginning of the block executed for the second and subsequent rows. */
+  if( regPeer ){
+    windowIfNewPeer(pParse, pOrderBy, regNewPeer, regPeer, lblWhereEnd);
+  }
+  if( pMWin->eStart==TK_FOLLOWING ){
+    windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0);
+    if( pMWin->eEnd!=TK_UNBOUNDED ){
+      if( pMWin->eFrmType==TK_RANGE ){
+        int lbl = sqlite3VdbeMakeLabel(pParse);
+        int addrNext = sqlite3VdbeCurrentAddr(v);
+        windowCodeRangeTest(&s, OP_Ge, s.current.csr, regEnd, s.end.csr, lbl);
+        windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+        windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+        sqlite3VdbeAddOp2(v, OP_Goto, 0, addrNext);
+        sqlite3VdbeResolveLabel(v, lbl);
+      }else{
+        windowCodeOp(&s, WINDOW_RETURN_ROW, regEnd, 0);
+        windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+      }
+    }
+  }else
+  if( pMWin->eEnd==TK_PRECEDING ){
+    int bRPS = (pMWin->eStart==TK_PRECEDING && pMWin->eFrmType==TK_RANGE);
+    windowCodeOp(&s, WINDOW_AGGSTEP, regEnd, 0);
+    if( bRPS ) windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+    windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+    if( !bRPS ) windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+  }else{
+    int addr = 0;
+    windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0);
+    if( pMWin->eEnd!=TK_UNBOUNDED ){
+      if( pMWin->eFrmType==TK_RANGE ){
+        int lbl = 0;
+        addr = sqlite3VdbeCurrentAddr(v);
+        if( regEnd ){
+          lbl = sqlite3VdbeMakeLabel(pParse);
+          windowCodeRangeTest(&s, OP_Ge, s.current.csr, regEnd, s.end.csr, lbl);
+        }
+        windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+        windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+        if( regEnd ){
+          sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
+          sqlite3VdbeResolveLabel(v, lbl);
+        }
+      }else{
+        if( regEnd ){
+          addr = sqlite3VdbeAddOp3(v, OP_IfPos, regEnd, 0, 1);
+          VdbeCoverage(v);
+        }
+        windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+        windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+        if( regEnd ) sqlite3VdbeJumpHere(v, addr);
+      }
+    }
+  }
+
+  /* End of the main input loop */
+  sqlite3VdbeResolveLabel(v, lblWhereEnd);
+  sqlite3WhereEnd(pWInfo);
+
+  /* Fall through */
+  if( pMWin->pPartition ){
+    addrInteger = sqlite3VdbeAddOp2(v, OP_Integer, 0, regFlushPart);
+    sqlite3VdbeJumpHere(v, addrGosubFlush);
+  }
+
+  s.regRowid = 0;
+  addrEmpty = sqlite3VdbeAddOp1(v, OP_Rewind, csrWrite);
+  VdbeCoverage(v);
+  if( pMWin->eEnd==TK_PRECEDING ){
+    int bRPS = (pMWin->eStart==TK_PRECEDING && pMWin->eFrmType==TK_RANGE);
+    windowCodeOp(&s, WINDOW_AGGSTEP, regEnd, 0);
+    if( bRPS ) windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+    windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 0);
+  }else if( pMWin->eStart==TK_FOLLOWING ){
+    int addrStart;
+    int addrBreak1;
+    int addrBreak2;
+    int addrBreak3;
+    windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0);
+    if( pMWin->eFrmType==TK_RANGE ){
+      addrStart = sqlite3VdbeCurrentAddr(v);
+      addrBreak2 = windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 1);
+      addrBreak1 = windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 1);
+    }else
+    if( pMWin->eEnd==TK_UNBOUNDED ){
+      addrStart = sqlite3VdbeCurrentAddr(v);
+      addrBreak1 = windowCodeOp(&s, WINDOW_RETURN_ROW, regStart, 1);
+      addrBreak2 = windowCodeOp(&s, WINDOW_AGGINVERSE, 0, 1);
+    }else{
+      assert( pMWin->eEnd==TK_FOLLOWING );
+      addrStart = sqlite3VdbeCurrentAddr(v);
+      addrBreak1 = windowCodeOp(&s, WINDOW_RETURN_ROW, regEnd, 1);
+      addrBreak2 = windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 1);
+    }
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart);
+    sqlite3VdbeJumpHere(v, addrBreak2);
+    addrStart = sqlite3VdbeCurrentAddr(v);
+    addrBreak3 = windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 1);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart);
+    sqlite3VdbeJumpHere(v, addrBreak1);
+    sqlite3VdbeJumpHere(v, addrBreak3);
+  }else{
+    int addrBreak;
+    int addrStart;
+    windowCodeOp(&s, WINDOW_AGGSTEP, 0, 0);
+    addrStart = sqlite3VdbeCurrentAddr(v);
+    addrBreak = windowCodeOp(&s, WINDOW_RETURN_ROW, 0, 1);
+    windowCodeOp(&s, WINDOW_AGGINVERSE, regStart, 0);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrStart);
+    sqlite3VdbeJumpHere(v, addrBreak);
+  }
+  sqlite3VdbeJumpHere(v, addrEmpty);
+
+  sqlite3VdbeAddOp1(v, OP_ResetSorter, s.current.csr);
+  if( pMWin->pPartition ){
+    if( pMWin->regStartRowid ){
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regStartRowid);
+      sqlite3VdbeAddOp2(v, OP_Integer, 0, pMWin->regEndRowid);
+    }
+    sqlite3VdbeChangeP1(v, addrInteger, sqlite3VdbeCurrentAddr(v));
+    sqlite3VdbeAddOp1(v, OP_Return, regFlushPart);
+  }
+}
+
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/************** End of window.c **********************************************/
+/************** Begin file parse.c *******************************************/
+/* This file is automatically generated by Lemon from input grammar
+** source file "parse.y" with these options:
+**
+**   -DSQLITE_ENABLE_UPDATE_DELETE_LIMIT
+*/
+/*
+** 2001-09-15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains SQLite's SQL parser.
+**
+** The canonical source code to this file ("parse.y") is a Lemon grammar
+** file that specifies the input grammar and actions to take while parsing.
+** That input file is processed by Lemon to generate a C-language
+** implementation of a parser for the given grammar.  You might be reading
+** this comment as part of the translated C-code.  Edits should be made
+** to the original parse.y sources.
+*/
+
+/* #include "sqliteInt.h" */
+
+/*
+** Disable all error recovery processing in the parser push-down
+** automaton.
+*/
+#define YYNOERRORRECOVERY 1
+
+/*
+** Make yytestcase() the same as testcase()
+*/
+#define yytestcase(X) testcase(X)
+
+/*
+** Indicate that sqlite3ParserFree() will never be called with a null
+** pointer.
+*/
+#define YYPARSEFREENEVERNULL 1
+
+/*
+** In the amalgamation, the parse.c file generated by lemon and the
+** tokenize.c file are concatenated.  In that case, sqlite3RunParser()
+** has access to the the size of the yyParser object and so the parser
+** engine can be allocated from stack.  In that case, only the
+** sqlite3ParserInit() and sqlite3ParserFinalize() routines are invoked
+** and the sqlite3ParserAlloc() and sqlite3ParserFree() routines can be
+** omitted.
+*/
+#ifdef SQLITE_AMALGAMATION
+# define sqlite3Parser_ENGINEALWAYSONSTACK 1
+#endif
+
+/*
+** Alternative datatype for the argument to the malloc() routine passed
+** into sqlite3ParserAlloc().  The default is size_t.
+*/
+#define YYMALLOCARGTYPE  u64
+
+/*
+** An instance of the following structure describes the event of a
+** TRIGGER.  "a" is the event type, one of TK_UPDATE, TK_INSERT,
+** TK_DELETE, or TK_INSTEAD.  If the event is of the form
+**
+**      UPDATE ON (a,b,c)
+**
+** Then the "b" IdList records the list "a,b,c".
+*/
+struct TrigEvent { int a; IdList * b; };
+
+struct FrameBound     { int eType; Expr *pExpr; };
+
+/*
+** Generate a syntax error
+*/
+static void parserSyntaxError(Parse *pParse, Token *p){
+  sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", p);
+}
+
+/*
+** Disable lookaside memory allocation for objects that might be
+** shared across database connections.
+*/
+static void disableLookaside(Parse *pParse){
+  sqlite3 *db = pParse->db;
+  pParse->disableLookaside++;
+  DisableLookaside;
+}
+
+#if !defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) \
+ && defined(SQLITE_UDL_CAPABLE_PARSER)
+/*
+** Issue an error message if an ORDER BY or LIMIT clause occurs on an
+** UPDATE or DELETE statement.
+*/
+static void updateDeleteLimitError(
+  Parse *pParse,
+  ExprList *pOrderBy,
+  Expr *pLimit
+){
+  if( pOrderBy ){
+    sqlite3ErrorMsg(pParse, "syntax error near \"ORDER BY\"");
+  }else{
+    sqlite3ErrorMsg(pParse, "syntax error near \"LIMIT\"");
+  }
+  sqlite3ExprListDelete(pParse->db, pOrderBy);
+  sqlite3ExprDelete(pParse->db, pLimit);
+}
+#endif /* SQLITE_ENABLE_UPDATE_DELETE_LIMIT */
+
+
+  /*
+  ** For a compound SELECT statement, make sure p->pPrior->pNext==p for
+  ** all elements in the list.  And make sure list length does not exceed
+  ** SQLITE_LIMIT_COMPOUND_SELECT.
+  */
+  static void parserDoubleLinkSelect(Parse *pParse, Select *p){
+    assert( p!=0 );
+    if( p->pPrior ){
+      Select *pNext = 0, *pLoop = p;
+      int mxSelect, cnt = 1;
+      while(1){
+        pLoop->pNext = pNext;
+        pLoop->selFlags |= SF_Compound;
+        pNext = pLoop;
+        pLoop = pLoop->pPrior;
+        if( pLoop==0 ) break;
+        cnt++;
+        if( pLoop->pOrderBy || pLoop->pLimit ){
+          sqlite3ErrorMsg(pParse,"%s clause should come after %s not before",
+             pLoop->pOrderBy!=0 ? "ORDER BY" : "LIMIT",
+             sqlite3SelectOpName(pNext->op));
+          break;
+        }
+      }
+      if( (p->selFlags & (SF_MultiValue|SF_Values))==0
+       && (mxSelect = pParse->db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT])>0
+       && cnt>mxSelect
+      ){
+        sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
+      }
+    }
+  }
+
+  /* Attach a With object describing the WITH clause to a Select
+  ** object describing the query for which the WITH clause is a prefix.
+  */
+  static Select *attachWithToSelect(Parse *pParse, Select *pSelect, With *pWith){
+    if( pSelect ){
+      pSelect->pWith = pWith;
+      parserDoubleLinkSelect(pParse, pSelect);
+    }else{
+      sqlite3WithDelete(pParse->db, pWith);
+    }
+    return pSelect;
+  }
+
+  /* Memory allocator for parser stack resizing.  This is a thin wrapper around
+  ** sqlite3_realloc() that includes a call to sqlite3FaultSim() to facilitate
+  ** testing.
+  */
+  static void *parserStackRealloc(void *pOld, sqlite3_uint64 newSize){
+    return sqlite3FaultSim(700) ? 0 : sqlite3_realloc(pOld, newSize);
+  }
+
+
+  /* Construct a new Expr object from a single token */
+  static Expr *tokenExpr(Parse *pParse, int op, Token t){
+    Expr *p = sqlite3DbMallocRawNN(pParse->db, sizeof(Expr)+t.n+1);
+    if( p ){
+      /* memset(p, 0, sizeof(Expr)); */
+      p->op = (u8)op;
+      p->affExpr = 0;
+      p->flags = EP_Leaf;
+      ExprClearVVAProperties(p);
+      /* p->iAgg = -1; // Not required */
+      p->pLeft = p->pRight = 0;
+      p->pAggInfo = 0;
+      memset(&p->x, 0, sizeof(p->x));
+      memset(&p->y, 0, sizeof(p->y));
+      p->op2 = 0;
+      p->iTable = 0;
+      p->iColumn = 0;
+      p->u.zToken = (char*)&p[1];
+      memcpy(p->u.zToken, t.z, t.n);
+      p->u.zToken[t.n] = 0;
+      p->w.iOfst = (int)(t.z - pParse->zTail);
+      if( sqlite3Isquote(p->u.zToken[0]) ){
+        sqlite3DequoteExpr(p);
+      }
+#if SQLITE_MAX_EXPR_DEPTH>0
+      p->nHeight = 1;
+#endif
+      if( IN_RENAME_OBJECT ){
+        return (Expr*)sqlite3RenameTokenMap(pParse, (void*)p, &t);
+      }
+    }
+    return p;
+  }
+
+
+  /* A routine to convert a binary TK_IS or TK_ISNOT expression into a
+  ** unary TK_ISNULL or TK_NOTNULL expression. */
+  static void binaryToUnaryIfNull(Parse *pParse, Expr *pY, Expr *pA, int op){
+    sqlite3 *db = pParse->db;
+    if( pA && pY && pY->op==TK_NULL && !IN_RENAME_OBJECT ){
+      pA->op = (u8)op;
+      sqlite3ExprDelete(db, pA->pRight);
+      pA->pRight = 0;
+    }
+  }
+
+  /* Add a single new term to an ExprList that is used to store a
+  ** list of identifiers.  Report an error if the ID list contains
+  ** a COLLATE clause or an ASC or DESC keyword, except ignore the
+  ** error while parsing a legacy schema.
+  */
+  static ExprList *parserAddExprIdListTerm(
+    Parse *pParse,
+    ExprList *pPrior,
+    Token *pIdToken,
+    int hasCollate,
+    int sortOrder
+  ){
+    ExprList *p = sqlite3ExprListAppend(pParse, pPrior, 0);
+    if( (hasCollate || sortOrder!=SQLITE_SO_UNDEFINED)
+        && pParse->db->init.busy==0
+    ){
+      sqlite3ErrorMsg(pParse, "syntax error after column name \"%.*s\"",
+                         pIdToken->n, pIdToken->z);
+    }
+    sqlite3ExprListSetName(pParse, p, pIdToken, 1);
+    return p;
+  }
+
+#if TK_SPAN>255
+# error too many tokens in the grammar
+#endif
+/**************** End of %include directives **********************************/
+/* These constants specify the various numeric values for terminal symbols.
+***************** Begin token definitions *************************************/
+#ifndef TK_SEMI
+#define TK_SEMI                            1
+#define TK_EXPLAIN                         2
+#define TK_QUERY                           3
+#define TK_PLAN                            4
+#define TK_BEGIN                           5
+#define TK_TRANSACTION                     6
+#define TK_DEFERRED                        7
+#define TK_IMMEDIATE                       8
+#define TK_EXCLUSIVE                       9
+#define TK_COMMIT                         10
+#define TK_END                            11
+#define TK_ROLLBACK                       12
+#define TK_SAVEPOINT                      13
+#define TK_RELEASE                        14
+#define TK_TO                             15
+#define TK_TABLE                          16
+#define TK_CREATE                         17
+#define TK_IF                             18
+#define TK_NOT                            19
+#define TK_EXISTS                         20
+#define TK_TEMP                           21
+#define TK_LP                             22
+#define TK_RP                             23
+#define TK_AS                             24
+#define TK_COMMA                          25
+#define TK_WITHOUT                        26
+#define TK_ABORT                          27
+#define TK_ACTION                         28
+#define TK_AFTER                          29
+#define TK_ANALYZE                        30
+#define TK_ASC                            31
+#define TK_ATTACH                         32
+#define TK_BEFORE                         33
+#define TK_BY                             34
+#define TK_CASCADE                        35
+#define TK_CAST                           36
+#define TK_CONFLICT                       37
+#define TK_DATABASE                       38
+#define TK_DESC                           39
+#define TK_DETACH                         40
+#define TK_EACH                           41
+#define TK_FAIL                           42
+#define TK_OR                             43
+#define TK_AND                            44
+#define TK_IS                             45
+#define TK_ISNOT                          46
+#define TK_MATCH                          47
+#define TK_LIKE_KW                        48
+#define TK_BETWEEN                        49
+#define TK_IN                             50
+#define TK_ISNULL                         51
+#define TK_NOTNULL                        52
+#define TK_NE                             53
+#define TK_EQ                             54
+#define TK_GT                             55
+#define TK_LE                             56
+#define TK_LT                             57
+#define TK_GE                             58
+#define TK_ESCAPE                         59
+#define TK_ID                             60
+#define TK_COLUMNKW                       61
+#define TK_DO                             62
+#define TK_FOR                            63
+#define TK_IGNORE                         64
+#define TK_INITIALLY                      65
+#define TK_INSTEAD                        66
+#define TK_NO                             67
+#define TK_KEY                            68
+#define TK_OF                             69
+#define TK_OFFSET                         70
+#define TK_PRAGMA                         71
+#define TK_RAISE                          72
+#define TK_RECURSIVE                      73
+#define TK_REPLACE                        74
+#define TK_RESTRICT                       75
+#define TK_ROW                            76
+#define TK_ROWS                           77
+#define TK_TRIGGER                        78
+#define TK_VACUUM                         79
+#define TK_VIEW                           80
+#define TK_VIRTUAL                        81
+#define TK_WITH                           82
+#define TK_NULLS                          83
+#define TK_FIRST                          84
+#define TK_LAST                           85
+#define TK_CURRENT                        86
+#define TK_FOLLOWING                      87
+#define TK_PARTITION                      88
+#define TK_PRECEDING                      89
+#define TK_RANGE                          90
+#define TK_UNBOUNDED                      91
+#define TK_EXCLUDE                        92
+#define TK_GROUPS                         93
+#define TK_OTHERS                         94
+#define TK_TIES                           95
+#define TK_GENERATED                      96
+#define TK_ALWAYS                         97
+#define TK_MATERIALIZED                   98
+#define TK_REINDEX                        99
+#define TK_RENAME                         100
+#define TK_CTIME_KW                       101
+#define TK_ANY                            102
+#define TK_BITAND                         103
+#define TK_BITOR                          104
+#define TK_LSHIFT                         105
+#define TK_RSHIFT                         106
+#define TK_PLUS                           107
+#define TK_MINUS                          108
+#define TK_STAR                           109
+#define TK_SLASH                          110
+#define TK_REM                            111
+#define TK_CONCAT                         112
+#define TK_PTR                            113
+#define TK_COLLATE                        114
+#define TK_BITNOT                         115
+#define TK_ON                             116
+#define TK_INDEXED                        117
+#define TK_STRING                         118
+#define TK_JOIN_KW                        119
+#define TK_CONSTRAINT                     120
+#define TK_DEFAULT                        121
+#define TK_NULL                           122
+#define TK_PRIMARY                        123
+#define TK_UNIQUE                         124
+#define TK_CHECK                          125
+#define TK_REFERENCES                     126
+#define TK_AUTOINCR                       127
+#define TK_INSERT                         128
+#define TK_DELETE                         129
+#define TK_UPDATE                         130
+#define TK_SET                            131
+#define TK_DEFERRABLE                     132
+#define TK_FOREIGN                        133
+#define TK_DROP                           134
+#define TK_UNION                          135
+#define TK_ALL                            136
+#define TK_EXCEPT                         137
+#define TK_INTERSECT                      138
+#define TK_SELECT                         139
+#define TK_VALUES                         140
+#define TK_DISTINCT                       141
+#define TK_DOT                            142
+#define TK_FROM                           143
+#define TK_JOIN                           144
+#define TK_USING                          145
+#define TK_ORDER                          146
+#define TK_GROUP                          147
+#define TK_HAVING                         148
+#define TK_LIMIT                          149
+#define TK_WHERE                          150
+#define TK_RETURNING                      151
+#define TK_INTO                           152
+#define TK_NOTHING                        153
+#define TK_FLOAT                          154
+#define TK_BLOB                           155
+#define TK_INTEGER                        156
+#define TK_VARIABLE                       157
+#define TK_CASE                           158
+#define TK_WHEN                           159
+#define TK_THEN                           160
+#define TK_ELSE                           161
+#define TK_INDEX                          162
+#define TK_ALTER                          163
+#define TK_ADD                            164
+#define TK_WINDOW                         165
+#define TK_OVER                           166
+#define TK_FILTER                         167
+#define TK_COLUMN                         168
+#define TK_AGG_FUNCTION                   169
+#define TK_AGG_COLUMN                     170
+#define TK_TRUEFALSE                      171
+#define TK_FUNCTION                       172
+#define TK_UPLUS                          173
+#define TK_UMINUS                         174
+#define TK_TRUTH                          175
+#define TK_REGISTER                       176
+#define TK_VECTOR                         177
+#define TK_SELECT_COLUMN                  178
+#define TK_IF_NULL_ROW                    179
+#define TK_ASTERISK                       180
+#define TK_SPAN                           181
+#define TK_ERROR                          182
+#define TK_QNUMBER                        183
+#define TK_SPACE                          184
+#define TK_COMMENT                        185
+#define TK_ILLEGAL                        186
+#endif
+/**************** End token definitions ***************************************/
+
+/* The next sections is a series of control #defines.
+** various aspects of the generated parser.
+**    YYCODETYPE         is the data type used to store the integer codes
+**                       that represent terminal and non-terminal symbols.
+**                       "unsigned char" is used if there are fewer than
+**                       256 symbols.  Larger types otherwise.
+**    YYNOCODE           is a number of type YYCODETYPE that is not used for
+**                       any terminal or nonterminal symbol.
+**    YYFALLBACK         If defined, this indicates that one or more tokens
+**                       (also known as: "terminal symbols") have fall-back
+**                       values which should be used if the original symbol
+**                       would not parse.  This permits keywords to sometimes
+**                       be used as identifiers, for example.
+**    YYACTIONTYPE       is the data type used for "action codes" - numbers
+**                       that indicate what to do in response to the next
+**                       token.
+**    sqlite3ParserTOKENTYPE     is the data type used for minor type for terminal
+**                       symbols.  Background: A "minor type" is a semantic
+**                       value associated with a terminal or non-terminal
+**                       symbols.  For example, for an "ID" terminal symbol,
+**                       the minor type might be the name of the identifier.
+**                       Each non-terminal can have a different minor type.
+**                       Terminal symbols all have the same minor type, though.
+**                       This macros defines the minor type for terminal
+**                       symbols.
+**    YYMINORTYPE        is the data type used for all minor types.
+**                       This is typically a union of many types, one of
+**                       which is sqlite3ParserTOKENTYPE.  The entry in the union
+**                       for terminal symbols is called "yy0".
+**    YYSTACKDEPTH       is the maximum depth of the parser's stack.  If
+**                       zero the stack is dynamically sized using realloc()
+**    sqlite3ParserARG_SDECL     A static variable declaration for the %extra_argument
+**    sqlite3ParserARG_PDECL     A parameter declaration for the %extra_argument
+**    sqlite3ParserARG_PARAM     Code to pass %extra_argument as a subroutine parameter
+**    sqlite3ParserARG_STORE     Code to store %extra_argument into yypParser
+**    sqlite3ParserARG_FETCH     Code to extract %extra_argument from yypParser
+**    sqlite3ParserCTX_*         As sqlite3ParserARG_ except for %extra_context
+**    YYREALLOC          Name of the realloc() function to use
+**    YYFREE             Name of the free() function to use
+**    YYDYNSTACK         True if stack space should be extended on heap
+**    YYERRORSYMBOL      is the code number of the error symbol.  If not
+**                       defined, then do no error processing.
+**    YYNSTATE           the combined number of states.
+**    YYNRULE            the number of rules in the grammar
+**    YYNTOKEN           Number of terminal symbols
+**    YY_MAX_SHIFT       Maximum value for shift actions
+**    YY_MIN_SHIFTREDUCE Minimum value for shift-reduce actions
+**    YY_MAX_SHIFTREDUCE Maximum value for shift-reduce actions
+**    YY_ERROR_ACTION    The yy_action[] code for syntax error
+**    YY_ACCEPT_ACTION   The yy_action[] code for accept
+**    YY_NO_ACTION       The yy_action[] code for no-op
+**    YY_MIN_REDUCE      Minimum value for reduce actions
+**    YY_MAX_REDUCE      Maximum value for reduce actions
+**    YY_MIN_DSTRCTR     Minimum symbol value that has a destructor
+**    YY_MAX_DSTRCTR     Maximum symbol value that has a destructor
+*/
+#ifndef INTERFACE
+# define INTERFACE 1
+#endif
+/************* Begin control #defines *****************************************/
+#define YYCODETYPE unsigned short int
+#define YYNOCODE 323
+#define YYACTIONTYPE unsigned short int
+#define YYWILDCARD 102
+#define sqlite3ParserTOKENTYPE Token
+typedef union {
+  int yyinit;
+  sqlite3ParserTOKENTYPE yy0;
+  u32 yy9;
+  struct TrigEvent yy28;
+  With* yy125;
+  IdList* yy204;
+  struct FrameBound yy205;
+  TriggerStep* yy319;
+  const char* yy342;
+  Cte* yy361;
+  ExprList* yy402;
+  Upsert* yy403;
+  OnOrUsing yy421;
+  u8 yy444;
+  struct {int value; int mask;} yy481;
+  Window* yy483;
+  int yy502;
+  SrcList* yy563;
+  Expr* yy590;
+  Select* yy637;
+} YYMINORTYPE;
+#ifndef YYSTACKDEPTH
+#define YYSTACKDEPTH 100
+#endif
+#define sqlite3ParserARG_SDECL
+#define sqlite3ParserARG_PDECL
+#define sqlite3ParserARG_PARAM
+#define sqlite3ParserARG_FETCH
+#define sqlite3ParserARG_STORE
+#define YYREALLOC parserStackRealloc
+#define YYFREE sqlite3_free
+#define YYDYNSTACK 1
+#define sqlite3ParserCTX_SDECL Parse *pParse;
+#define sqlite3ParserCTX_PDECL ,Parse *pParse
+#define sqlite3ParserCTX_PARAM ,pParse
+#define sqlite3ParserCTX_FETCH Parse *pParse=yypParser->pParse;
+#define sqlite3ParserCTX_STORE yypParser->pParse=pParse;
+#define YYFALLBACK 1
+#define YYNSTATE             587
+#define YYNRULE              409
+#define YYNRULE_WITH_ACTION  344
+#define YYNTOKEN             187
+#define YY_MAX_SHIFT         586
+#define YY_MIN_SHIFTREDUCE   849
+#define YY_MAX_SHIFTREDUCE   1257
+#define YY_ERROR_ACTION      1258
+#define YY_ACCEPT_ACTION     1259
+#define YY_NO_ACTION         1260
+#define YY_MIN_REDUCE        1261
+#define YY_MAX_REDUCE        1669
+#define YY_MIN_DSTRCTR       206
+#define YY_MAX_DSTRCTR       320
+/************* End control #defines *******************************************/
+#define YY_NLOOKAHEAD ((int)(sizeof(yy_lookahead)/sizeof(yy_lookahead[0])))
+
+/* Define the yytestcase() macro to be a no-op if is not already defined
+** otherwise.
+**
+** Applications can choose to define yytestcase() in the %include section
+** to a macro that can assist in verifying code coverage.  For production
+** code the yytestcase() macro should be turned off.  But it is useful
+** for testing.
+*/
+#ifndef yytestcase
+# define yytestcase(X)
+#endif
+
+/* Macro to determine if stack space has the ability to grow using
+** heap memory.
+*/
+#if YYSTACKDEPTH<=0 || YYDYNSTACK
+# define YYGROWABLESTACK 1
+#else
+# define YYGROWABLESTACK 0
+#endif
+
+/* Guarantee a minimum number of initial stack slots.
+*/
+#if YYSTACKDEPTH<=0
+# undef YYSTACKDEPTH
+# define YYSTACKDEPTH 2  /* Need a minimum stack size */
+#endif
+
+
+/* Next are the tables used to determine what action to take based on the
+** current state and lookahead token.  These tables are used to implement
+** functions that take a state number and lookahead value and return an
+** action integer.
+**
+** Suppose the action integer is N.  Then the action is determined as
+** follows
+**
+**   0 <= N <= YY_MAX_SHIFT             Shift N.  That is, push the lookahead
+**                                      token onto the stack and goto state N.
+**
+**   N between YY_MIN_SHIFTREDUCE       Shift to an arbitrary state then
+**     and YY_MAX_SHIFTREDUCE           reduce by rule N-YY_MIN_SHIFTREDUCE.
+**
+**   N == YY_ERROR_ACTION               A syntax error has occurred.
+**
+**   N == YY_ACCEPT_ACTION              The parser accepts its input.
+**
+**   N == YY_NO_ACTION                  No such action.  Denotes unused
+**                                      slots in the yy_action[] table.
+**
+**   N between YY_MIN_REDUCE            Reduce by rule N-YY_MIN_REDUCE
+**     and YY_MAX_REDUCE
+**
+** The action table is constructed as a single large table named yy_action[].
+** Given state S and lookahead X, the action is computed as either:
+**
+**    (A)   N = yy_action[ yy_shift_ofst[S] + X ]
+**    (B)   N = yy_default[S]
+**
+** The (A) formula is preferred.  The B formula is used instead if
+** yy_lookahead[yy_shift_ofst[S]+X] is not equal to X.
+**
+** The formulas above are for computing the action when the lookahead is
+** a terminal symbol.  If the lookahead is a non-terminal (as occurs after
+** a reduce action) then the yy_reduce_ofst[] array is used in place of
+** the yy_shift_ofst[] array.
+**
+** The following are the tables generated in this section:
+**
+**  yy_action[]        A single table containing all actions.
+**  yy_lookahead[]     A table containing the lookahead for each entry in
+**                     yy_action.  Used to detect hash collisions.
+**  yy_shift_ofst[]    For each state, the offset into yy_action for
+**                     shifting terminals.
+**  yy_reduce_ofst[]   For each state, the offset into yy_action for
+**                     shifting non-terminals after a reduce.
+**  yy_default[]       Default action for each state.
+**
+*********** Begin parsing tables **********************************************/
+#define YY_ACTTAB_COUNT (2207)
+static const YYACTIONTYPE yy_action[] = {
+ /*     0 */   130,  127,  234,  282,  282, 1332,  580, 1311,  464,  289,
+ /*    10 */   289,  580, 1626,  385,  580, 1332,  577,  580,  566,  417,
+ /*    20 */  1304, 1546,  577,  485,  566,  528,  464,  463,  562,   82,
+ /*    30 */    82,  987,  294,  379,   51,   51,  502,   61,   61,  988,
+ /*    40 */    82,   82, 1581,  137,  138,   91,    7, 1232, 1232, 1067,
+ /*    50 */  1070, 1057, 1057,  135,  135,  136,  136,  136,  136,  417,
+ /*    60 */   288,  288,  182,  288,  288,  485,  540,  288,  288,  130,
+ /*    70 */   127,  234,  436,  577,  529,  566,  577,  561,  566, 1294,
+ /*    80 */   577,  425,  566,  137,  138,   91,  563, 1232, 1232, 1067,
+ /*    90 */  1070, 1057, 1057,  135,  135,  136,  136,  136,  136,  296,
+ /*   100 */   464,  402, 1253,  134,  134,  134,  134,  133,  133,  132,
+ /*   110 */   132,  132,  131,  128,  455,  455, 1054, 1054, 1068, 1071,
+ /*   120 */  1259,    1,    1,  586,    2, 1263,  585, 1178, 1263, 1178,
+ /*   130 */   321,  417,  155,  321, 1588,  155,  383,  112,  485, 1345,
+ /*   140 */   460,  299, 1345,  134,  134,  134,  134,  133,  133,  132,
+ /*   150 */   132,  132,  131,  128,  455,  137,  138,   91,  502, 1232,
+ /*   160 */  1232, 1067, 1070, 1057, 1057,  135,  135,  136,  136,  136,
+ /*   170 */   136, 1208,  866, 1285,  288,  288,  283,  288,  288,  527,
+ /*   180 */   527, 1254,  139,  582,    7,  582, 1349,  577, 1173,  566,
+ /*   190 */   577, 1058,  566,  136,  136,  136,  136,  129,  577,  551,
+ /*   200 */   566, 1173,  245, 1545, 1173,  245,  133,  133,  132,  132,
+ /*   210 */   132,  131,  128,  455,  302,  134,  134,  134,  134,  133,
+ /*   220 */   133,  132,  132,  132,  131,  128,  455, 1579, 1208, 1209,
+ /*   230 */  1208,    7,  474,  554,  459,  417,  554,  459,  130,  127,
+ /*   240 */   234,  134,  134,  134,  134,  133,  133,  132,  132,  132,
+ /*   250 */   131,  128,  455,  136,  136,  136,  136,  542,  487,  137,
+ /*   260 */   138,   91, 1023, 1232, 1232, 1067, 1070, 1057, 1057,  135,
+ /*   270 */   135,  136,  136,  136,  136, 1089,  580, 1208,  132,  132,
+ /*   280 */   132,  131,  128,  455,   93,  214,  134,  134,  134,  134,
+ /*   290 */   133,  133,  132,  132,  132,  131,  128,  455,  405,   19,
+ /*   300 */    19,  134,  134,  134,  134,  133,  133,  132,  132,  132,
+ /*   310 */   131,  128,  455, 1502,  430,  267,  348,  471,  334,  134,
+ /*   320 */   134,  134,  134,  133,  133,  132,  132,  132,  131,  128,
+ /*   330 */   455, 1285,  580,    6, 1208, 1209, 1208,  257,  580,  417,
+ /*   340 */   515,  512,  511, 1283,   94, 1023,  468, 1208,  555,  555,
+ /*   350 */   510, 1228, 1575,   44,   38,   51,   51,  415,  580,  417,
+ /*   360 */    45,   51,   51,  137,  138,   91,  534, 1232, 1232, 1067,
+ /*   370 */  1070, 1057, 1057,  135,  135,  136,  136,  136,  136,  402,
+ /*   380 */  1152,   82,   82,  137,  138,   91,   39, 1232, 1232, 1067,
+ /*   390 */  1070, 1057, 1057,  135,  135,  136,  136,  136,  136,  348,
+ /*   400 */    44,  288,  288,  379, 1208, 1209, 1208,  209, 1208, 1228,
+ /*   410 */   320,  571,  475,  580,  577,  580,  566,  580,  316,  264,
+ /*   420 */   231,   46,  160,  134,  134,  134,  134,  133,  133,  132,
+ /*   430 */   132,  132,  131,  128,  455,  303,   82,   82,   82,   82,
+ /*   440 */    82,   82,  446,  134,  134,  134,  134,  133,  133,  132,
+ /*   450 */   132,  132,  131,  128,  455, 1586,  548,  320,  571, 1254,
+ /*   460 */   878, 1586,  384,  386,  417, 1208, 1209, 1208,  364,  182,
+ /*   470 */   288,  288, 1580,  561, 1343,  561,    7,  561, 1281,  476,
+ /*   480 */   350,  530,  535,  577,  560,  566,  443, 1515,  137,  138,
+ /*   490 */    91,  219, 1232, 1232, 1067, 1070, 1057, 1057,  135,  135,
+ /*   500 */   136,  136,  136,  136,  469, 1515, 1517,  536,  417,  288,
+ /*   510 */   288,  427,  516,  288,  288,  415,  288,  288,  878,  130,
+ /*   520 */   127,  234,  577, 1111,  566, 1208,  577, 1111,  566,  577,
+ /*   530 */   564,  566,  137,  138,   91, 1297, 1232, 1232, 1067, 1070,
+ /*   540 */  1057, 1057,  135,  135,  136,  136,  136,  136,  134,  134,
+ /*   550 */   134,  134,  133,  133,  132,  132,  132,  131,  128,  455,
+ /*   560 */   497,  507, 1296, 1208,  257,  288,  288,  515,  512,  511,
+ /*   570 */  1208, 1632, 1173,  123,  572,  275,    4,  510,  577, 1515,
+ /*   580 */   566,  331, 1208, 1209, 1208, 1173,  552,  552, 1173,  261,
+ /*   590 */   575,    7,  134,  134,  134,  134,  133,  133,  132,  132,
+ /*   600 */   132,  131,  128,  455,  108,  537,  130,  127,  234, 1208,
+ /*   610 */   452,  451,  417, 1455,  456,  987,  890,   96, 1602, 1237,
+ /*   620 */  1208, 1209, 1208,  988, 1239, 1454,  569, 1208, 1209, 1208,
+ /*   630 */   229,  526, 1238,  538, 1337, 1337,  137,  138,   91, 1453,
+ /*   640 */  1232, 1232, 1067, 1070, 1057, 1057,  135,  135,  136,  136,
+ /*   650 */   136,  136,  377, 1599,  975, 1044,  417, 1240,  422, 1240,
+ /*   660 */   883,  121,  121,  952,  377, 1599, 1208, 1209, 1208,  122,
+ /*   670 */  1208,  456,  581,  456,  367,  421, 1032,  886,  377, 1599,
+ /*   680 */   137,  138,   91,  466, 1232, 1232, 1067, 1070, 1057, 1057,
+ /*   690 */   135,  135,  136,  136,  136,  136,  134,  134,  134,  134,
+ /*   700 */   133,  133,  132,  132,  132,  131,  128,  455, 1032, 1032,
+ /*   710 */  1034, 1035,   35,  574,  574,  574,  197,  427, 1044,  198,
+ /*   720 */  1208,  123,  572, 1208,    4,  320,  571, 1208, 1209, 1208,
+ /*   730 */    40,  392,  580,  388,  886, 1033,  427, 1192,  575, 1032,
+ /*   740 */   134,  134,  134,  134,  133,  133,  132,  132,  132,  131,
+ /*   750 */   128,  455,  533, 1572, 1208,   19,   19, 1208,  579,  496,
+ /*   760 */   417,  157,  456,  493, 1191, 1335, 1335,    5, 1208,  953,
+ /*   770 */   435, 1032, 1032, 1034,  569,   22,   22, 1208, 1209, 1208,
+ /*   780 */  1208, 1209, 1208,  481,  137,  138,   91,  212, 1232, 1232,
+ /*   790 */  1067, 1070, 1057, 1057,  135,  135,  136,  136,  136,  136,
+ /*   800 */  1192,   48,  111, 1044,  417, 1208,  213,  974, 1045,  121,
+ /*   810 */   121, 1208, 1209, 1208, 1208, 1209, 1208,  122,  221,  456,
+ /*   820 */   581,  456,   44,  491, 1032, 1208, 1209, 1208,  137,  138,
+ /*   830 */    91,  382, 1232, 1232, 1067, 1070, 1057, 1057,  135,  135,
+ /*   840 */   136,  136,  136,  136,  134,  134,  134,  134,  133,  133,
+ /*   850 */   132,  132,  132,  131,  128,  455, 1032, 1032, 1034, 1035,
+ /*   860 */    35,  465, 1208, 1209, 1208, 1573, 1044,  381,  214, 1153,
+ /*   870 */  1661,  539, 1661,  441,  906,  320,  571, 1572,  368,  320,
+ /*   880 */   571,  416,  329, 1033,  523, 1192,    3, 1032,  134,  134,
+ /*   890 */   134,  134,  133,  133,  132,  132,  132,  131,  128,  455,
+ /*   900 */  1663,  403, 1173,  307,  897,  307,  519,  580,  417,  214,
+ /*   910 */   502,  948, 1028,  544,  907, 1173,  947,  396, 1173, 1032,
+ /*   920 */  1032, 1034,  410,  298, 1208,   50, 1153, 1662,  417, 1662,
+ /*   930 */   145,  145,  137,  138,   91,  293, 1232, 1232, 1067, 1070,
+ /*   940 */  1057, 1057,  135,  135,  136,  136,  136,  136, 1192, 1151,
+ /*   950 */   518, 1572,  137,  138,   91, 1509, 1232, 1232, 1067, 1070,
+ /*   960 */  1057, 1057,  135,  135,  136,  136,  136,  136,  438,  323,
+ /*   970 */   439,  543,  111, 1510,  274,  291,  376,  521,  371,  520,
+ /*   980 */   262, 1208, 1209, 1208, 1578,  485,  367,  580,    7, 1573,
+ /*   990 */  1572,  381,  134,  134,  134,  134,  133,  133,  132,  132,
+ /*  1000 */   132,  131,  128,  455, 1572,  580, 1151,  580,  232,  580,
+ /*  1010 */    19,   19,  134,  134,  134,  134,  133,  133,  132,  132,
+ /*  1020 */   132,  131,  128,  455, 1173,  437,  580, 1211,   19,   19,
+ /*  1030 */    19,   19,   19,   19, 1631,  580,  915, 1173,   47,  120,
+ /*  1040 */  1173,  117,  417,  306,  502,  442, 1129,  206,  340,   19,
+ /*  1050 */    19, 1439,   49,  453,  453,  453, 1372,  315,   81,   81,
+ /*  1060 */   580,  304,  417, 1574,  207,  381,  137,  138,   91,  115,
+ /*  1070 */  1232, 1232, 1067, 1070, 1057, 1057,  135,  135,  136,  136,
+ /*  1080 */   136,  136,  580,   82,   82, 1211,  137,  138,   91, 1344,
+ /*  1090 */  1232, 1232, 1067, 1070, 1057, 1057,  135,  135,  136,  136,
+ /*  1100 */   136,  136, 1573,  390,  381,   82,   82,  467, 1130, 1556,
+ /*  1110 */   337,  467,  339,  131,  128,  455, 1573,  161,  381,   16,
+ /*  1120 */   317,  391,  432, 1131,  452,  451,  134,  134,  134,  134,
+ /*  1130 */   133,  133,  132,  132,  132,  131,  128,  455, 1132,  580,
+ /*  1140 */  1109,   10,  449,  267,  580, 1558,  134,  134,  134,  134,
+ /*  1150 */   133,  133,  132,  132,  132,  131,  128,  455,  536,  580,
+ /*  1160 */   926,  580,   19,   19,  580, 1577,  580,  147,  147,    7,
+ /*  1170 */   927, 1240,  502, 1240,  580,  491,  417,  556,  285, 1228,
+ /*  1180 */   973,  215,   82,   82,   66,   66, 1439,   67,   67,   21,
+ /*  1190 */    21, 1114, 1114,  499,  338,  297,  417,   53,   53,  297,
+ /*  1200 */   137,  138,   91,  119, 1232, 1232, 1067, 1070, 1057, 1057,
+ /*  1210 */   135,  135,  136,  136,  136,  136,  417, 1340, 1315,  450,
+ /*  1220 */   137,  138,   91,  227, 1232, 1232, 1067, 1070, 1057, 1057,
+ /*  1230 */   135,  135,  136,  136,  136,  136,  578, 1228,  940,  940,
+ /*  1240 */   137,  126,   91,  141, 1232, 1232, 1067, 1070, 1057, 1057,
+ /*  1250 */   135,  135,  136,  136,  136,  136,  537,  433,  476,  350,
+ /*  1260 */   134,  134,  134,  134,  133,  133,  132,  132,  132,  131,
+ /*  1270 */   128,  455,  580,  461,  233,  347, 1439,  407,  502, 1554,
+ /*  1280 */   134,  134,  134,  134,  133,  133,  132,  132,  132,  131,
+ /*  1290 */   128,  455,  580,  324,  580,   82,   82,  491,  580,  973,
+ /*  1300 */   134,  134,  134,  134,  133,  133,  132,  132,  132,  131,
+ /*  1310 */   128,  455,  288,  288,  550,   68,   68,   54,   54,  557,
+ /*  1320 */   417,   69,   69,  355,    6,  577,  948,  566,  414,  413,
+ /*  1330 */  1439,  947,  454,  549,  260,  259,  258,  580,  158,  580,
+ /*  1340 */   417,  222, 1184,  483,  973,  138,   91,  434, 1232, 1232,
+ /*  1350 */  1067, 1070, 1057, 1057,  135,  135,  136,  136,  136,  136,
+ /*  1360 */    70,   70,   71,   71,  580, 1130,   91,  580, 1232, 1232,
+ /*  1370 */  1067, 1070, 1057, 1057,  135,  135,  136,  136,  136,  136,
+ /*  1380 */  1131,  166,  854,  855,  856, 1286,  423,   72,   72,  108,
+ /*  1390 */    73,   73, 1314,  362, 1184, 1132,  580,  305,  580,  123,
+ /*  1400 */   572,  498,    4,  492,  134,  134,  134,  134,  133,  133,
+ /*  1410 */   132,  132,  132,  131,  128,  455,  575,  568,  538,   55,
+ /*  1420 */    55,   56,   56,  580,  134,  134,  134,  134,  133,  133,
+ /*  1430 */   132,  132,  132,  131,  128,  455,  580, 1108,  233, 1108,
+ /*  1440 */   456, 1606,  586,    2, 1263,  580,   57,   57,  580,  321,
+ /*  1450 */   580,  155,  569, 1439,  489,  357,  580,  360, 1345,   59,
+ /*  1460 */    59,  580,   44,  973,  573,  423,  580,  238,   60,   60,
+ /*  1470 */   261,   74,   74,   75,   75,  287,  231,  580, 1370,   76,
+ /*  1480 */    76, 1044,  424,  184,   20,   20,  580,  121,  121,   77,
+ /*  1490 */    77,   97,  218,  288,  288,  122,  125,  456,  581,  456,
+ /*  1500 */   143,  143, 1032,  580,  524,  580,  577,  580,  566,  144,
+ /*  1510 */   144,  478,  227, 1248,  482,  123,  572,  580,    4,  320,
+ /*  1520 */   571,  245,  415,  580,  447,  415,   78,   78,   62,   62,
+ /*  1530 */    79,   79,  575,  319, 1032, 1032, 1034, 1035,   35,  422,
+ /*  1540 */    63,   63,  580,  290,  415,    9,   80,   80, 1148,  580,
+ /*  1550 */   404,  580,  490,  459,  580, 1227,  456,  580,  325,  346,
+ /*  1560 */   580,  111,  580, 1192,  242,   64,   64,  477,  569,  580,
+ /*  1570 */    23,  580,  170,  170,  171,  171,  580,   87,   87,  328,
+ /*  1580 */    65,   65,  546,   83,   83,  146,  146,  545,  123,  572,
+ /*  1590 */   345,    4,   84,   84,  168,  168,  580, 1044,  580,  148,
+ /*  1600 */   148,  580, 1384,  121,  121,  575, 1025,  580,  266,  580,
+ /*  1610 */   428,  122,  580,  456,  581,  456,  580,  557, 1032,  142,
+ /*  1620 */   142,  169,  169,  580,  162,  162,  532,  893,  375,  456,
+ /*  1630 */   152,  152,  151,  151, 1383,  149,  149,  109,  374,  150,
+ /*  1640 */   150,  569,  580,  484,  580,  266,   86,   86,  580, 1096,
+ /*  1650 */  1032, 1032, 1034, 1035,   35,  546,  486,  580,  266,  470,
+ /*  1660 */   547,  123,  572, 1620,    4,   88,   88,   85,   85,  479,
+ /*  1670 */  1044,   52,   52,  222,  905,  904,  121,  121,  575, 1192,
+ /*  1680 */    58,   58,  244, 1036,  122,  893,  456,  581,  456,  912,
+ /*  1690 */   913, 1032,  300,  351,  508,  111,  263,  365,  165,  111,
+ /*  1700 */   111, 1092,  456,  263,  978, 1157,  266, 1096,  990,  991,
+ /*  1710 */   946,  943,  125,  125,  569, 1107,  876, 1107,  159,  945,
+ /*  1720 */  1313,  125, 1561, 1032, 1032, 1034, 1035,   35,  546,  341,
+ /*  1730 */  1534,  205, 1533,  545,  503, 1593,  494,  352, 1380,  356,
+ /*  1740 */   359, 1036,  361, 1044,  363, 1328, 1312,  370,  567,  121,
+ /*  1750 */   121,  380, 1192, 1393, 1438, 1366,  280,  122, 1378,  456,
+ /*  1760 */   581,  456,  167, 1443, 1032, 1293, 1284, 1272, 1271, 1273,
+ /*  1770 */  1613, 1363,  312,  313,  314,  401,   12,  237,  224, 1425,
+ /*  1780 */   295,  333,  336, 1430,  343,  488,  344,  513, 1375, 1616,
+ /*  1790 */  1376, 1429, 1248,  408,  301,  228, 1032, 1032, 1034, 1035,
+ /*  1800 */    35, 1605, 1196,  458,  349, 1311,  292,  373, 1506, 1505,
+ /*  1810 */   270,  400,  400,  399,  277,  397, 1374, 1373,  863, 1553,
+ /*  1820 */   186,  123,  572,  235,    4, 1192,  395,  210,  211,  223,
+ /*  1830 */  1551,  239, 1245,  327,  426,   96,  220,  195,  575,  140,
+ /*  1840 */   557,  326,  180,  472, 1420,  332,  188, 1413,  335,  570,
+ /*  1850 */   190,  191,  192,  193,  473,  506,  247,  109, 1434,  495,
+ /*  1860 */   251,  199,  456,  406,  480, 1426,   13,  409,  102,   14,
+ /*  1870 */   501, 1511,  241, 1432,  569, 1431,  203,   92,   95, 1500,
+ /*  1880 */   175,  281,  358,   43,  504,  253,  411,  254,  522, 1331,
+ /*  1890 */   104, 1274, 1522,  354,  440, 1322,  255, 1330, 1630, 1629,
+ /*  1900 */   240,  897,  229, 1044,  444, 1321,  445,  448,  269,  121,
+ /*  1910 */   121, 1329,  531,  268,  310,  412, 1398,  122, 1301,  456,
+ /*  1920 */   581,  456, 1300,  372, 1032, 1299, 1628,  378,  311,   90,
+ /*  1930 */   572,   11,    4, 1397, 1598,  418, 1487,  389,  116,  110,
+ /*  1940 */   320,  571, 1584,  559,  318,  541,  575, 1583,   42, 1354,
+ /*  1950 */   387,  583,  216, 1353, 1202,  276, 1032, 1032, 1034, 1035,
+ /*  1960 */    35,  393,  394,  278,  462,  279,  419,  584, 1538, 1269,
+ /*  1970 */   456, 1264,  172,  420,  173, 1539, 1537, 1536,  156,  308,
+ /*  1980 */   225,   89,  569,  850,  226, 1192,  457,  174,  217,  236,
+ /*  1990 */   322,  154, 1106, 1104,  187,  330,  176, 1227,  929,  189,
+ /*  2000 */   243,  342,  246, 1120,  194,  177,  178,  429,  431,   98,
+ /*  2010 */   196, 1044,   99,  185,  100,  101,  179,  121,  121, 1123,
+ /*  2020 */   248,  249, 1119,  163,  250,  122,   24,  456,  581,  456,
+ /*  2030 */  1196,  458, 1032,  353,  292,  266, 1112,  200, 1242,  400,
+ /*  2040 */   400,  399,  277,  397,  500,  252,  863,  201,  292,   15,
+ /*  2050 */   865,  558,  505,  400,  400,  399,  277,  397,  374,  239,
+ /*  2060 */   863,  327,  256,  202, 1032, 1032, 1034, 1035,   35,  326,
+ /*  2070 */   103,   25,   26,  239,  509,  327,  366,  514,  369,  895,
+ /*  2080 */   908,  517,  105,  326,  309,  164,  525,  106,  181,   27,
+ /*  2090 */  1189, 1073,   17, 1192,  107, 1159, 1158,  284,  230,  286,
+ /*  2100 */   241,  204,  125, 1175,  982,  265, 1182,  976,  175,   28,
+ /*  2110 */  1179,   43,   29, 1177,  241,   30,   31,    8, 1183,   32,
+ /*  2120 */  1164,   41,  175,  208,  553,   43,  111,   33,  240, 1087,
+ /*  2130 */  1074,  113,  114, 1072, 1076,   34, 1077,  565, 1128,  118,
+ /*  2140 */   271,   36,  240,   18,  939, 1037,  877,  272,  124,   37,
+ /*  2150 */   398, 1198, 1197,  576,  183,  273,  153, 1621, 1260, 1260,
+ /*  2160 */  1260, 1260, 1260,  418, 1260, 1260, 1260, 1260,  320,  571,
+ /*  2170 */  1260, 1260, 1260, 1260, 1260, 1260, 1260,  418, 1260, 1260,
+ /*  2180 */  1260, 1260,  320,  571, 1260, 1260, 1260, 1260, 1260, 1260,
+ /*  2190 */  1260, 1260,  462, 1260, 1260, 1260, 1260, 1260, 1260, 1260,
+ /*  2200 */  1260, 1260, 1260, 1260, 1260, 1260,  462,
+};
+static const YYCODETYPE yy_lookahead[] = {
+ /*     0 */   277,  278,  279,  241,  242,  225,  195,  227,  195,  241,
+ /*    10 */   242,  195,  217,  221,  195,  235,  254,  195,  256,   19,
+ /*    20 */   225,  298,  254,  195,  256,  206,  213,  214,  206,  218,
+ /*    30 */   219,   31,  206,  195,  218,  219,  195,  218,  219,   39,
+ /*    40 */   218,  219,  313,   43,   44,   45,  317,   47,   48,   49,
+ /*    50 */    50,   51,   52,   53,   54,   55,   56,   57,   58,   19,
+ /*    60 */   241,  242,  195,  241,  242,  195,  255,  241,  242,  277,
+ /*    70 */   278,  279,  234,  254,  255,  256,  254,  255,  256,  218,
+ /*    80 */   254,  240,  256,   43,   44,   45,  264,   47,   48,   49,
+ /*    90 */    50,   51,   52,   53,   54,   55,   56,   57,   58,  271,
+ /*   100 */   287,   22,   23,  103,  104,  105,  106,  107,  108,  109,
+ /*   110 */   110,  111,  112,  113,  114,  114,   47,   48,   49,   50,
+ /*   120 */   187,  188,  189,  190,  191,  192,  190,   87,  192,   89,
+ /*   130 */   197,   19,  199,  197,  318,  199,  320,   25,  195,  206,
+ /*   140 */   299,  271,  206,  103,  104,  105,  106,  107,  108,  109,
+ /*   150 */   110,  111,  112,  113,  114,   43,   44,   45,  195,   47,
+ /*   160 */    48,   49,   50,   51,   52,   53,   54,   55,   56,   57,
+ /*   170 */    58,   60,   21,  195,  241,  242,  215,  241,  242,  312,
+ /*   180 */   313,  102,   70,  205,  317,  207,  242,  254,   77,  256,
+ /*   190 */   254,  122,  256,   55,   56,   57,   58,   59,  254,   88,
+ /*   200 */   256,   90,  269,  240,   93,  269,  107,  108,  109,  110,
+ /*   210 */   111,  112,  113,  114,  271,  103,  104,  105,  106,  107,
+ /*   220 */   108,  109,  110,  111,  112,  113,  114,  313,  117,  118,
+ /*   230 */   119,  317,   81,  195,  301,   19,  195,  301,  277,  278,
+ /*   240 */   279,  103,  104,  105,  106,  107,  108,  109,  110,  111,
+ /*   250 */   112,  113,  114,   55,   56,   57,   58,  146,  195,   43,
+ /*   260 */    44,   45,   74,   47,   48,   49,   50,   51,   52,   53,
+ /*   270 */    54,   55,   56,   57,   58,  124,  195,   60,  109,  110,
+ /*   280 */   111,  112,  113,  114,   68,  195,  103,  104,  105,  106,
+ /*   290 */   107,  108,  109,  110,  111,  112,  113,  114,  208,  218,
+ /*   300 */   219,  103,  104,  105,  106,  107,  108,  109,  110,  111,
+ /*   310 */   112,  113,  114,  162,  233,   24,  128,  129,  130,  103,
+ /*   320 */   104,  105,  106,  107,  108,  109,  110,  111,  112,  113,
+ /*   330 */   114,  195,  195,  215,  117,  118,  119,  120,  195,   19,
+ /*   340 */   123,  124,  125,  207,   24,   74,  246,   60,  310,  311,
+ /*   350 */   133,   60,  311,   82,   22,  218,  219,  257,  195,   19,
+ /*   360 */    73,  218,  219,   43,   44,   45,  206,   47,   48,   49,
+ /*   370 */    50,   51,   52,   53,   54,   55,   56,   57,   58,   22,
+ /*   380 */    23,  218,  219,   43,   44,   45,   54,   47,   48,   49,
+ /*   390 */    50,   51,   52,   53,   54,   55,   56,   57,   58,  128,
+ /*   400 */    82,  241,  242,  195,  117,  118,  119,  289,   60,  118,
+ /*   410 */   139,  140,  294,  195,  254,  195,  256,  195,  255,  259,
+ /*   420 */   260,   73,   22,  103,  104,  105,  106,  107,  108,  109,
+ /*   430 */   110,  111,  112,  113,  114,  206,  218,  219,  218,  219,
+ /*   440 */   218,  219,  234,  103,  104,  105,  106,  107,  108,  109,
+ /*   450 */   110,  111,  112,  113,  114,  318,  319,  139,  140,  102,
+ /*   460 */    60,  318,  319,  221,   19,  117,  118,  119,   23,  195,
+ /*   470 */   241,  242,  313,  255,  206,  255,  317,  255,  206,  129,
+ /*   480 */   130,  206,  264,  254,  264,  256,  264,  195,   43,   44,
+ /*   490 */    45,  151,   47,   48,   49,   50,   51,   52,   53,   54,
+ /*   500 */    55,   56,   57,   58,  246,  213,  214,   19,   19,  241,
+ /*   510 */   242,  195,   23,  241,  242,  257,  241,  242,  118,  277,
+ /*   520 */   278,  279,  254,   29,  256,   60,  254,   33,  256,  254,
+ /*   530 */   206,  256,   43,   44,   45,  218,   47,   48,   49,   50,
+ /*   540 */    51,   52,   53,   54,   55,   56,   57,   58,  103,  104,
+ /*   550 */   105,  106,  107,  108,  109,  110,  111,  112,  113,  114,
+ /*   560 */    66,   19,  218,   60,  120,  241,  242,  123,  124,  125,
+ /*   570 */    60,  232,   77,   19,   20,   26,   22,  133,  254,  287,
+ /*   580 */   256,  265,  117,  118,  119,   90,  312,  313,   93,   47,
+ /*   590 */    36,  317,  103,  104,  105,  106,  107,  108,  109,  110,
+ /*   600 */   111,  112,  113,  114,  116,  117,  277,  278,  279,   60,
+ /*   610 */   107,  108,   19,  276,   60,   31,   23,  152,  195,  116,
+ /*   620 */   117,  118,  119,   39,  121,  276,   72,  117,  118,  119,
+ /*   630 */   166,  167,  129,  145,  237,  238,   43,   44,   45,  276,
+ /*   640 */    47,   48,   49,   50,   51,   52,   53,   54,   55,   56,
+ /*   650 */    57,   58,  315,  316,  144,  101,   19,  154,  116,  156,
+ /*   660 */    23,  107,  108,  109,  315,  316,  117,  118,  119,  115,
+ /*   670 */    60,  117,  118,  119,  132,  200,  122,   60,  315,  316,
+ /*   680 */    43,   44,   45,  272,   47,   48,   49,   50,   51,   52,
+ /*   690 */    53,   54,   55,   56,   57,   58,  103,  104,  105,  106,
+ /*   700 */   107,  108,  109,  110,  111,  112,  113,  114,  154,  155,
+ /*   710 */   156,  157,  158,  212,  213,  214,   22,  195,  101,   22,
+ /*   720 */    60,   19,   20,   60,   22,  139,  140,  117,  118,  119,
+ /*   730 */    22,  251,  195,  253,  117,  118,  195,  183,   36,  122,
+ /*   740 */   103,  104,  105,  106,  107,  108,  109,  110,  111,  112,
+ /*   750 */   113,  114,  195,  195,   60,  218,  219,   60,  195,  284,
+ /*   760 */    19,   25,   60,  288,   23,  237,  238,   22,   60,  109,
+ /*   770 */   233,  154,  155,  156,   72,  218,  219,  117,  118,  119,
+ /*   780 */   117,  118,  119,  116,   43,   44,   45,  265,   47,   48,
+ /*   790 */    49,   50,   51,   52,   53,   54,   55,   56,   57,   58,
+ /*   800 */   183,  243,   25,  101,   19,   60,  265,  144,   23,  107,
+ /*   810 */   108,  117,  118,  119,  117,  118,  119,  115,  151,  117,
+ /*   820 */   118,  119,   82,  195,  122,  117,  118,  119,   43,   44,
+ /*   830 */    45,  195,   47,   48,   49,   50,   51,   52,   53,   54,
+ /*   840 */    55,   56,   57,   58,  103,  104,  105,  106,  107,  108,
+ /*   850 */   109,  110,  111,  112,  113,  114,  154,  155,  156,  157,
+ /*   860 */   158,  121,  117,  118,  119,  307,  101,  309,  195,   22,
+ /*   870 */    23,  195,   25,   19,   35,  139,  140,  195,   24,  139,
+ /*   880 */   140,  208,  195,  118,  109,  183,   22,  122,  103,  104,
+ /*   890 */   105,  106,  107,  108,  109,  110,  111,  112,  113,  114,
+ /*   900 */   304,  305,   77,  230,  127,  232,   67,  195,   19,  195,
+ /*   910 */   195,  136,   23,   88,   75,   90,  141,  203,   93,  154,
+ /*   920 */   155,  156,  208,  295,   60,  243,   22,   23,   19,   25,
+ /*   930 */   218,  219,   43,   44,   45,  100,   47,   48,   49,   50,
+ /*   940 */    51,   52,   53,   54,   55,   56,   57,   58,  183,  102,
+ /*   950 */    96,  195,   43,   44,   45,  240,   47,   48,   49,   50,
+ /*   960 */    51,   52,   53,   54,   55,   56,   57,   58,  114,  134,
+ /*   970 */   131,  146,   25,  286,  120,  121,  122,  123,  124,  125,
+ /*   980 */   126,  117,  118,  119,  313,  195,  132,  195,  317,  307,
+ /*   990 */   195,  309,  103,  104,  105,  106,  107,  108,  109,  110,
+ /*  1000 */   111,  112,  113,  114,  195,  195,  102,  195,  195,  195,
+ /*  1010 */   218,  219,  103,  104,  105,  106,  107,  108,  109,  110,
+ /*  1020 */   111,  112,  113,  114,   77,  233,  195,   60,  218,  219,
+ /*  1030 */   218,  219,  218,  219,   23,  195,   25,   90,  243,  159,
+ /*  1040 */    93,  161,   19,  233,  195,  233,   23,  233,   16,  218,
+ /*  1050 */   219,  195,  243,  212,  213,  214,  262,  263,  218,  219,
+ /*  1060 */   195,  271,   19,  307,  233,  309,   43,   44,   45,  160,
+ /*  1070 */    47,   48,   49,   50,   51,   52,   53,   54,   55,   56,
+ /*  1080 */    57,   58,  195,  218,  219,  118,   43,   44,   45,  240,
+ /*  1090 */    47,   48,   49,   50,   51,   52,   53,   54,   55,   56,
+ /*  1100 */    57,   58,  307,  195,  309,  218,  219,  263,   12,  195,
+ /*  1110 */    78,  267,   80,  112,  113,  114,  307,   22,  309,   24,
+ /*  1120 */   255,  281,  266,   27,  107,  108,  103,  104,  105,  106,
+ /*  1130 */   107,  108,  109,  110,  111,  112,  113,  114,   42,  195,
+ /*  1140 */    11,   22,  255,   24,  195,  195,  103,  104,  105,  106,
+ /*  1150 */   107,  108,  109,  110,  111,  112,  113,  114,   19,  195,
+ /*  1160 */    64,  195,  218,  219,  195,  313,  195,  218,  219,  317,
+ /*  1170 */    74,  154,  195,  156,  195,  195,   19,  233,   23,   60,
+ /*  1180 */    25,   24,  218,  219,  218,  219,  195,  218,  219,  218,
+ /*  1190 */   219,  128,  129,  130,  162,  263,   19,  218,  219,  267,
+ /*  1200 */    43,   44,   45,  160,   47,   48,   49,   50,   51,   52,
+ /*  1210 */    53,   54,   55,   56,   57,   58,   19,  240,  228,  255,
+ /*  1220 */    43,   44,   45,   25,   47,   48,   49,   50,   51,   52,
+ /*  1230 */    53,   54,   55,   56,   57,   58,  135,  118,  137,  138,
+ /*  1240 */    43,   44,   45,   22,   47,   48,   49,   50,   51,   52,
+ /*  1250 */    53,   54,   55,   56,   57,   58,  117,  266,  129,  130,
+ /*  1260 */   103,  104,  105,  106,  107,  108,  109,  110,  111,  112,
+ /*  1270 */   113,  114,  195,  195,  119,  295,  195,  206,  195,  195,
+ /*  1280 */   103,  104,  105,  106,  107,  108,  109,  110,  111,  112,
+ /*  1290 */   113,  114,  195,  195,  195,  218,  219,  195,  195,  144,
+ /*  1300 */   103,  104,  105,  106,  107,  108,  109,  110,  111,  112,
+ /*  1310 */   113,  114,  241,  242,   67,  218,  219,  218,  219,  146,
+ /*  1320 */    19,  218,  219,  240,  215,  254,  136,  256,  107,  108,
+ /*  1330 */   195,  141,  255,   86,  128,  129,  130,  195,  165,  195,
+ /*  1340 */    19,  143,   95,  272,   25,   44,   45,  266,   47,   48,
+ /*  1350 */    49,   50,   51,   52,   53,   54,   55,   56,   57,   58,
+ /*  1360 */   218,  219,  218,  219,  195,   12,   45,  195,   47,   48,
+ /*  1370 */    49,   50,   51,   52,   53,   54,   55,   56,   57,   58,
+ /*  1380 */    27,   23,    7,    8,    9,  210,  211,  218,  219,  116,
+ /*  1390 */   218,  219,  228,   16,  147,   42,  195,  295,  195,   19,
+ /*  1400 */    20,  266,   22,  294,  103,  104,  105,  106,  107,  108,
+ /*  1410 */   109,  110,  111,  112,  113,  114,   36,   64,  145,  218,
+ /*  1420 */   219,  218,  219,  195,  103,  104,  105,  106,  107,  108,
+ /*  1430 */   109,  110,  111,  112,  113,  114,  195,  154,  119,  156,
+ /*  1440 */    60,  189,  190,  191,  192,  195,  218,  219,  195,  197,
+ /*  1450 */   195,  199,   72,  195,   19,   78,  195,   80,  206,  218,
+ /*  1460 */   219,  195,   82,  144,  210,  211,  195,   15,  218,  219,
+ /*  1470 */    47,  218,  219,  218,  219,  259,  260,  195,  261,  218,
+ /*  1480 */   219,  101,  302,  303,  218,  219,  195,  107,  108,  218,
+ /*  1490 */   219,  150,  151,  241,  242,  115,   25,  117,  118,  119,
+ /*  1500 */   218,  219,  122,  195,  146,  195,  254,  195,  256,  218,
+ /*  1510 */   219,  246,   25,   61,  246,   19,   20,  195,   22,  139,
+ /*  1520 */   140,  269,  257,  195,  266,  257,  218,  219,  218,  219,
+ /*  1530 */   218,  219,   36,  246,  154,  155,  156,  157,  158,  116,
+ /*  1540 */   218,  219,  195,   22,  257,   49,  218,  219,   23,  195,
+ /*  1550 */    25,  195,  117,  301,  195,   25,   60,  195,  195,   23,
+ /*  1560 */   195,   25,  195,  183,   24,  218,  219,  130,   72,  195,
+ /*  1570 */    22,  195,  218,  219,  218,  219,  195,  218,  219,  195,
+ /*  1580 */   218,  219,   86,  218,  219,  218,  219,   91,   19,   20,
+ /*  1590 */   153,   22,  218,  219,  218,  219,  195,  101,  195,  218,
+ /*  1600 */   219,  195,  195,  107,  108,   36,   23,  195,   25,  195,
+ /*  1610 */    62,  115,  195,  117,  118,  119,  195,  146,  122,  218,
+ /*  1620 */   219,  218,  219,  195,  218,  219,   19,   60,  122,   60,
+ /*  1630 */   218,  219,  218,  219,  195,  218,  219,  150,  132,  218,
+ /*  1640 */   219,   72,  195,   23,  195,   25,  218,  219,  195,   60,
+ /*  1650 */   154,  155,  156,  157,  158,   86,   23,  195,   25,  195,
+ /*  1660 */    91,   19,   20,  142,   22,  218,  219,  218,  219,  130,
+ /*  1670 */   101,  218,  219,  143,  121,  122,  107,  108,   36,  183,
+ /*  1680 */   218,  219,  142,   60,  115,  118,  117,  118,  119,    7,
+ /*  1690 */     8,  122,  153,   23,   23,   25,   25,   23,   23,   25,
+ /*  1700 */    25,   23,   60,   25,   23,   98,   25,  118,   84,   85,
+ /*  1710 */    23,   23,   25,   25,   72,  154,   23,  156,   25,   23,
+ /*  1720 */   228,   25,  195,  154,  155,  156,  157,  158,   86,  195,
+ /*  1730 */   195,  258,  195,   91,  291,  322,  195,  195,  195,  195,
+ /*  1740 */   195,  118,  195,  101,  195,  195,  195,  195,  238,  107,
+ /*  1750 */   108,  195,  183,  195,  195,  195,  290,  115,  195,  117,
+ /*  1760 */   118,  119,  244,  195,  122,  195,  195,  195,  195,  195,
+ /*  1770 */   195,  258,  258,  258,  258,  193,  245,  300,  216,  274,
+ /*  1780 */   247,  270,  270,  274,  296,  296,  248,  222,  262,  198,
+ /*  1790 */   262,  274,   61,  274,  248,  231,  154,  155,  156,  157,
+ /*  1800 */   158,    0,    1,    2,  247,  227,    5,  221,  221,  221,
+ /*  1810 */   142,   10,   11,   12,   13,   14,  262,  262,   17,  202,
+ /*  1820 */   300,   19,   20,  300,   22,  183,  247,  251,  251,  245,
+ /*  1830 */   202,   30,   38,   32,  202,  152,  151,   22,   36,  149,
+ /*  1840 */   146,   40,   43,   18,  252,  251,  236,  252,  251,  283,
+ /*  1850 */   239,  239,  239,  239,  202,   18,  201,  150,  236,  202,
+ /*  1860 */   201,  236,   60,  248,  248,  275,  273,  248,  159,  273,
+ /*  1870 */    63,  286,   71,  275,   72,  275,   22,  297,  297,  248,
+ /*  1880 */    79,  202,  202,   82,  223,  201,  223,  201,  116,  220,
+ /*  1890 */    22,  202,  293,  292,   65,  229,  201,  220,  226,  226,
+ /*  1900 */    99,  127,  166,  101,   24,  229,  114,   83,   92,  107,
+ /*  1910 */   108,  220,  308,  202,  285,  223,  268,  115,  220,  117,
+ /*  1920 */   118,  119,  222,  220,  122,  220,  220,  223,  285,   19,
+ /*  1930 */    20,   22,   22,  268,  316,  134,  280,  202,  159,  148,
+ /*  1940 */   139,  140,  321,  141,  282,  147,   36,  321,   25,  252,
+ /*  1950 */   251,  204,  250,  252,   13,  196,  154,  155,  156,  157,
+ /*  1960 */   158,  249,  248,  196,  163,    6,  306,  194,  215,  194,
+ /*  1970 */    60,  194,  209,  306,  209,  215,  215,  215,  224,  224,
+ /*  1980 */   216,  215,   72,    4,  216,  183,    3,  209,   22,   15,
+ /*  1990 */   164,   16,   23,   23,  152,  140,  131,   25,   20,  143,
+ /*  2000 */    24,   16,  145,    1,  143,  131,  131,   62,   37,   54,
+ /*  2010 */   152,  101,   54,  303,   54,   54,  131,  107,  108,  117,
+ /*  2020 */    34,  142,    1,    5,  116,  115,   22,  117,  118,  119,
+ /*  2030 */     1,    2,  122,  162,    5,   25,   69,   69,   76,   10,
+ /*  2040 */    11,   12,   13,   14,   41,  142,   17,  116,    5,   24,
+ /*  2050 */    20,  141,   19,   10,   11,   12,   13,   14,  132,   30,
+ /*  2060 */    17,   32,  126,   22,  154,  155,  156,  157,  158,   40,
+ /*  2070 */    22,   22,   22,   30,   68,   32,   23,   68,   24,   60,
+ /*  2080 */    28,   97,   22,   40,   68,   23,   22,  150,   37,   34,
+ /*  2090 */    23,   23,   22,  183,   25,   23,   98,   23,  142,   23,
+ /*  2100 */    71,   22,   25,   89,  117,   34,   94,  144,   79,   34,
+ /*  2110 */    76,   82,   34,   87,   71,   34,   34,   44,   76,   34,
+ /*  2120 */    23,   22,   79,   25,   24,   82,   25,   34,   99,   23,
+ /*  2130 */    23,  143,  143,   23,   23,   22,   11,   25,   23,   25,
+ /*  2140 */    22,   22,   99,   22,  136,   23,   23,  142,   22,   22,
+ /*  2150 */    15,    1,    1,   25,   25,  142,   23,  142,  323,  323,
+ /*  2160 */   323,  323,  323,  134,  323,  323,  323,  323,  139,  140,
+ /*  2170 */   323,  323,  323,  323,  323,  323,  323,  134,  323,  323,
+ /*  2180 */   323,  323,  139,  140,  323,  323,  323,  323,  323,  323,
+ /*  2190 */   323,  323,  163,  323,  323,  323,  323,  323,  323,  323,
+ /*  2200 */   323,  323,  323,  323,  323,  323,  163,  323,  323,  323,
+ /*  2210 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2220 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2230 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2240 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2250 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2260 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2270 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2280 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2290 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2300 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2310 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2320 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2330 */   323,  323,  323,  323,  323,  323,  323,  323,  323,  323,
+ /*  2340 */   323,  323,  323,  323,  323,  187,  187,  187,  187,  187,
+ /*  2350 */   187,  187,  187,  187,  187,  187,  187,  187,  187,  187,
+ /*  2360 */   187,  187,  187,  187,  187,  187,  187,  187,  187,  187,
+ /*  2370 */   187,  187,  187,  187,  187,  187,  187,  187,  187,  187,
+ /*  2380 */   187,  187,  187,  187,  187,  187,  187,  187,  187,  187,
+ /*  2390 */   187,  187,  187,  187,
+};
+#define YY_SHIFT_COUNT    (586)
+#define YY_SHIFT_MIN      (0)
+#define YY_SHIFT_MAX      (2151)
+static const unsigned short int yy_shift_ofst[] = {
+ /*     0 */  2029, 1801, 2043, 1380, 1380,  318,  271, 1496, 1569, 1642,
+ /*    10 */   702,  702,  702,  740,  318,  318,  318,  318,  318,    0,
+ /*    20 */     0,  216, 1177,  702,  702,  702,  702,  702,  702,  702,
+ /*    30 */   702,  702,  702,  702,  702,  702,  702,  702,  503,  503,
+ /*    40 */   111,  111,  217,  287,  348,  610,  610,  736,  736,  736,
+ /*    50 */   736,   40,  112,  320,  340,  445,  489,  593,  637,  741,
+ /*    60 */   785,  889,  909, 1023, 1043, 1157, 1177, 1177, 1177, 1177,
+ /*    70 */  1177, 1177, 1177, 1177, 1177, 1177, 1177, 1177, 1177, 1177,
+ /*    80 */  1177, 1177, 1177, 1177, 1197, 1177, 1301, 1321, 1321,  554,
+ /*    90 */  1802, 1910,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   100 */   702,  702,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   110 */   702,  702,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   120 */   702,  702,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   130 */   702,  702,  702,  702,  702,  702,  702,  702,  702,  702,
+ /*   140 */   702,  702,  138,  198,  198,  198,  198,  198,  198,  198,
+ /*   150 */   183,   99,  169,  549,  610,  151,  542,  610,  610, 1017,
+ /*   160 */  1017,  610, 1001,  350,  464,  464,  464,  586,    1,    1,
+ /*   170 */  2207, 2207,  854,  854,  854,  465,  694,  694,  694,  694,
+ /*   180 */  1096, 1096,  825,  549,  847,  904,  610,  610,  610,  610,
+ /*   190 */   610,  610,  610,  610,  610,  610,  610,  610,  610,  610,
+ /*   200 */   610,  610,  610,  610,  610,  488,  947,  947,  610, 1129,
+ /*   210 */   495,  495, 1139, 1139,  967,  967, 1173, 2207, 2207, 2207,
+ /*   220 */  2207, 2207, 2207, 2207,  617,  765,  765,  697,  444,  708,
+ /*   230 */   660,  745,  510,  663,  864,  610,  610,  610,  610,  610,
+ /*   240 */   610,  610,  610,  610,  610,  188,  610,  610,  610,  610,
+ /*   250 */   610,  610,  610,  610,  610,  610,  610,  610,  839,  839,
+ /*   260 */   839,  610,  610,  610, 1155,  610,  610,  610, 1119, 1247,
+ /*   270 */   610, 1353,  610,  610,  610,  610,  610,  610,  610,  610,
+ /*   280 */  1063,  494, 1101,  291,  291,  291,  291, 1319, 1101, 1101,
+ /*   290 */   775, 1221, 1375, 1452,  667, 1341, 1198, 1341, 1435, 1487,
+ /*   300 */   667,  667, 1487,  667, 1198, 1435,  777, 1011, 1423,  584,
+ /*   310 */   584,  584, 1273, 1273, 1273, 1273, 1471, 1471,  880, 1530,
+ /*   320 */  1190, 1095, 1731, 1731, 1668, 1668, 1794, 1794, 1668, 1683,
+ /*   330 */  1685, 1815, 1690, 1694, 1799, 1690, 1694, 1825, 1825, 1825,
+ /*   340 */  1825, 1668, 1837, 1707, 1685, 1685, 1707, 1815, 1799, 1707,
+ /*   350 */  1799, 1707, 1668, 1837, 1709, 1807, 1668, 1837, 1854, 1668,
+ /*   360 */  1837, 1668, 1837, 1854, 1772, 1772, 1772, 1829, 1868, 1868,
+ /*   370 */  1854, 1772, 1774, 1772, 1829, 1772, 1772, 1736, 1880, 1792,
+ /*   380 */  1792, 1854, 1668, 1816, 1816, 1824, 1824, 1690, 1694, 1909,
+ /*   390 */  1668, 1779, 1690, 1791, 1798, 1707, 1923, 1941, 1941, 1959,
+ /*   400 */  1959, 1959, 2207, 2207, 2207, 2207, 2207, 2207, 2207, 2207,
+ /*   410 */  2207, 2207, 2207, 2207, 2207, 2207, 2207,   69, 1032,   79,
+ /*   420 */   357, 1377, 1206,  400, 1525,  835,  332, 1540, 1437, 1539,
+ /*   430 */  1536, 1548, 1583, 1620, 1633, 1670, 1671, 1674, 1567, 1553,
+ /*   440 */  1682, 1506, 1675, 1358, 1607, 1589, 1678, 1681, 1624, 1687,
+ /*   450 */  1688, 1283, 1561, 1693, 1696, 1623, 1521, 1979, 1983, 1966,
+ /*   460 */  1826, 1974, 1975, 1969, 1970, 1855, 1842, 1865, 1972, 1972,
+ /*   470 */  1976, 1856, 1978, 1857, 1985, 2002, 1861, 1874, 1972, 1875,
+ /*   480 */  1945, 1971, 1972, 1858, 1955, 1958, 1960, 1961, 1885, 1902,
+ /*   490 */  1986, 1879, 2021, 2018, 2004, 1908, 1871, 1967, 2010, 1968,
+ /*   500 */  1962, 2003, 1903, 1931, 2025, 2030, 2033, 1926, 1936, 2041,
+ /*   510 */  2006, 2048, 2049, 2053, 2050, 2009, 2019, 2054, 1984, 2052,
+ /*   520 */  2060, 2016, 2051, 2062, 2055, 1937, 2064, 2067, 2068, 2069,
+ /*   530 */  2072, 2070, 1998, 1956, 2074, 2076, 1987, 2071, 2079, 1963,
+ /*   540 */  2077, 2075, 2078, 2081, 2082, 2014, 2034, 2026, 2073, 2042,
+ /*   550 */  2012, 2085, 2097, 2099, 2100, 2098, 2101, 2093, 1988, 1989,
+ /*   560 */  2106, 2077, 2107, 2110, 2111, 2113, 2112, 2114, 2115, 2118,
+ /*   570 */  2125, 2119, 2121, 2122, 2123, 2126, 2127, 2128, 2008, 2005,
+ /*   580 */  2013, 2015, 2129, 2133, 2135, 2150, 2151,
+};
+#define YY_REDUCE_COUNT (416)
+#define YY_REDUCE_MIN   (-277)
+#define YY_REDUCE_MAX   (1778)
+static const short yy_reduce_ofst[] = {
+ /*     0 */   -67, 1252,  -64, -178, -181,  160, 1071,  143, -184,  137,
+ /*    10 */   218,  220,  222, -174,  229,  268,  272,  275,  324, -208,
+ /*    20 */   242, -277,  -39,   81,  537,  792,  810,  812, -189,  814,
+ /*    30 */   831,  163,  865,  944,  887,  840,  964, 1077, -187,  292,
+ /*    40 */  -133,  274,  673,  558,  682,  795,  809, -238, -232, -238,
+ /*    50 */  -232,  329,  329,  329,  329,  329,  329,  329,  329,  329,
+ /*    60 */   329,  329,  329,  329,  329,  329,  329,  329,  329,  329,
+ /*    70 */   329,  329,  329,  329,  329,  329,  329,  329,  329,  329,
+ /*    80 */   329,  329,  329,  329,  329,  329,  329,  329,  329,  557,
+ /*    90 */   712,  949,  966,  969,  971,  979, 1097, 1099, 1103, 1142,
+ /*   100 */  1144, 1169, 1172, 1201, 1203, 1228, 1241, 1250, 1253, 1255,
+ /*   110 */  1261, 1266, 1271, 1282, 1291, 1308, 1310, 1312, 1322, 1328,
+ /*   120 */  1347, 1354, 1356, 1359, 1362, 1365, 1367, 1374, 1376, 1381,
+ /*   130 */  1401, 1403, 1406, 1412, 1414, 1417, 1421, 1428, 1447, 1449,
+ /*   140 */  1453, 1462,  329,  329,  329,  329,  329,  329,  329,  329,
+ /*   150 */   329,  329,  329,  -22, -159,  475, -220,  756,   38,  501,
+ /*   160 */   841,  714,  329,  118,  337,  349,  363,  -56,  329,  329,
+ /*   170 */   329,  329, -205, -205, -205,  687, -172, -130,  -57,  790,
+ /*   180 */   397,  528, -271,  136,  596,  596,   90,  316,  522,  541,
+ /*   190 */   -37,  715,  849,  977,  628,  856,  980,  991, 1081, 1102,
+ /*   200 */  1135, 1083, -162,  208, 1258,  794,  -86,  159,   41, 1109,
+ /*   210 */   671,  852,  844,  932, 1175, 1254,  480, 1180,  100,  258,
+ /*   220 */  1265, 1268, 1216, 1287, -139,  317,  344,   63,  339,  423,
+ /*   230 */   563,  636,  676,  813,  908,  914,  950, 1078, 1084, 1098,
+ /*   240 */  1363, 1384, 1407, 1439, 1464,  411, 1527, 1534, 1535, 1537,
+ /*   250 */  1541, 1542, 1543, 1544, 1545, 1547, 1549, 1550,  990, 1164,
+ /*   260 */  1492, 1551, 1552, 1556, 1217, 1558, 1559, 1560, 1473, 1413,
+ /*   270 */  1563, 1510, 1568,  563, 1570, 1571, 1572, 1573, 1574, 1575,
+ /*   280 */  1443, 1466, 1518, 1513, 1514, 1515, 1516, 1217, 1518, 1518,
+ /*   290 */  1531, 1562, 1582, 1477, 1505, 1511, 1533, 1512, 1488, 1538,
+ /*   300 */  1509, 1517, 1546, 1519, 1557, 1489, 1565, 1564, 1578, 1586,
+ /*   310 */  1587, 1588, 1526, 1528, 1554, 1555, 1576, 1577, 1566, 1579,
+ /*   320 */  1584, 1591, 1520, 1523, 1617, 1628, 1580, 1581, 1632, 1585,
+ /*   330 */  1590, 1593, 1592, 1594, 1610, 1595, 1597, 1611, 1612, 1613,
+ /*   340 */  1614, 1652, 1655, 1615, 1598, 1600, 1616, 1596, 1622, 1619,
+ /*   350 */  1625, 1631, 1657, 1659, 1599, 1601, 1679, 1684, 1661, 1680,
+ /*   360 */  1686, 1689, 1695, 1663, 1669, 1677, 1691, 1666, 1672, 1673,
+ /*   370 */  1692, 1698, 1700, 1703, 1676, 1705, 1706, 1618, 1604, 1629,
+ /*   380 */  1643, 1704, 1711, 1621, 1626, 1648, 1665, 1697, 1699, 1656,
+ /*   390 */  1735, 1662, 1701, 1702, 1712, 1714, 1747, 1759, 1767, 1773,
+ /*   400 */  1775, 1777, 1660, 1667, 1710, 1763, 1753, 1760, 1761, 1762,
+ /*   410 */  1765, 1754, 1755, 1764, 1768, 1766, 1778,
+};
+static const YYACTIONTYPE yy_default[] = {
+ /*     0 */  1667, 1667, 1667, 1495, 1258, 1371, 1258, 1258, 1258, 1258,
+ /*    10 */  1495, 1495, 1495, 1258, 1258, 1258, 1258, 1258, 1258, 1401,
+ /*    20 */  1401, 1548, 1291, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*    30 */  1258, 1258, 1258, 1258, 1258, 1494, 1258, 1258, 1258, 1258,
+ /*    40 */  1582, 1582, 1258, 1258, 1258, 1258, 1258, 1567, 1566, 1258,
+ /*    50 */  1258, 1258, 1410, 1258, 1417, 1258, 1258, 1258, 1258, 1258,
+ /*    60 */  1496, 1497, 1258, 1258, 1258, 1258, 1547, 1549, 1512, 1424,
+ /*    70 */  1423, 1422, 1421, 1530, 1389, 1415, 1408, 1412, 1491, 1492,
+ /*    80 */  1490, 1645, 1497, 1496, 1258, 1411, 1459, 1475, 1458, 1258,
+ /*    90 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   100 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   110 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   120 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   130 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   140 */  1258, 1258, 1467, 1474, 1473, 1472, 1481, 1471, 1468, 1461,
+ /*   150 */  1460, 1462, 1463, 1282, 1258, 1279, 1333, 1258, 1258, 1258,
+ /*   160 */  1258, 1258, 1464, 1291, 1452, 1451, 1450, 1258, 1478, 1465,
+ /*   170 */  1477, 1476, 1555, 1619, 1618, 1513, 1258, 1258, 1258, 1258,
+ /*   180 */  1258, 1258, 1582, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   190 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   200 */  1258, 1258, 1258, 1258, 1258, 1391, 1582, 1582, 1258, 1291,
+ /*   210 */  1582, 1582, 1392, 1392, 1287, 1287, 1395, 1562, 1362, 1362,
+ /*   220 */  1362, 1362, 1371, 1362, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   230 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1552,
+ /*   240 */  1550, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   250 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   260 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1367, 1258,
+ /*   270 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1612,
+ /*   280 */  1258, 1525, 1347, 1367, 1367, 1367, 1367, 1369, 1348, 1346,
+ /*   290 */  1361, 1292, 1265, 1659, 1427, 1416, 1368, 1416, 1656, 1414,
+ /*   300 */  1427, 1427, 1414, 1427, 1368, 1656, 1308, 1634, 1303, 1401,
+ /*   310 */  1401, 1401, 1391, 1391, 1391, 1391, 1395, 1395, 1493, 1368,
+ /*   320 */  1361, 1258, 1659, 1659, 1377, 1377, 1658, 1658, 1377, 1513,
+ /*   330 */  1642, 1436, 1409, 1395, 1336, 1409, 1395, 1342, 1342, 1342,
+ /*   340 */  1342, 1377, 1276, 1414, 1642, 1642, 1414, 1436, 1336, 1414,
+ /*   350 */  1336, 1414, 1377, 1276, 1529, 1653, 1377, 1276, 1503, 1377,
+ /*   360 */  1276, 1377, 1276, 1503, 1334, 1334, 1334, 1323, 1258, 1258,
+ /*   370 */  1503, 1334, 1308, 1334, 1323, 1334, 1334, 1600, 1258, 1507,
+ /*   380 */  1507, 1503, 1377, 1592, 1592, 1404, 1404, 1409, 1395, 1498,
+ /*   390 */  1377, 1258, 1409, 1407, 1405, 1414, 1326, 1615, 1615, 1611,
+ /*   400 */  1611, 1611, 1664, 1664, 1562, 1627, 1291, 1291, 1291, 1291,
+ /*   410 */  1627, 1310, 1310, 1292, 1292, 1291, 1627, 1258, 1258, 1258,
+ /*   420 */  1258, 1258, 1258, 1622, 1258, 1557, 1514, 1381, 1258, 1258,
+ /*   430 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   440 */  1258, 1258, 1258, 1258, 1568, 1258, 1258, 1258, 1258, 1258,
+ /*   450 */  1258, 1258, 1258, 1258, 1258, 1258, 1441, 1258, 1261, 1559,
+ /*   460 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1418, 1419,
+ /*   470 */  1382, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1433, 1258,
+ /*   480 */  1258, 1258, 1428, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   490 */  1258, 1655, 1258, 1258, 1258, 1258, 1258, 1258, 1528, 1527,
+ /*   500 */  1258, 1258, 1379, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   510 */  1258, 1258, 1258, 1258, 1258, 1258, 1306, 1258, 1258, 1258,
+ /*   520 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   530 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   540 */  1406, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258, 1258,
+ /*   550 */  1258, 1258, 1258, 1258, 1258, 1597, 1396, 1258, 1258, 1258,
+ /*   560 */  1258, 1646, 1258, 1258, 1258, 1258, 1356, 1258, 1258, 1258,
+ /*   570 */  1258, 1258, 1258, 1258, 1258, 1258, 1258, 1638, 1350, 1442,
+ /*   580 */  1258, 1445, 1280, 1258, 1270, 1258, 1258,
+};
+/********** End of lemon-generated parsing tables *****************************/
+
+/* The next table maps tokens (terminal symbols) into fallback tokens.
+** If a construct like the following:
+**
+**      %fallback ID X Y Z.
+**
+** appears in the grammar, then ID becomes a fallback token for X, Y,
+** and Z.  Whenever one of the tokens X, Y, or Z is input to the parser
+** but it does not parse, the type of the token is changed to ID and
+** the parse is retried before an error is thrown.
+**
+** This feature can be used, for example, to cause some keywords in a language
+** to revert to identifiers if they keyword does not apply in the context where
+** it appears.
+*/
+#ifdef YYFALLBACK
+static const YYCODETYPE yyFallback[] = {
+    0,  /*          $ => nothing */
+    0,  /*       SEMI => nothing */
+   60,  /*    EXPLAIN => ID */
+   60,  /*      QUERY => ID */
+   60,  /*       PLAN => ID */
+   60,  /*      BEGIN => ID */
+    0,  /* TRANSACTION => nothing */
+   60,  /*   DEFERRED => ID */
+   60,  /*  IMMEDIATE => ID */
+   60,  /*  EXCLUSIVE => ID */
+    0,  /*     COMMIT => nothing */
+   60,  /*        END => ID */
+   60,  /*   ROLLBACK => ID */
+   60,  /*  SAVEPOINT => ID */
+   60,  /*    RELEASE => ID */
+    0,  /*         TO => nothing */
+    0,  /*      TABLE => nothing */
+    0,  /*     CREATE => nothing */
+   60,  /*         IF => ID */
+    0,  /*        NOT => nothing */
+    0,  /*     EXISTS => nothing */
+   60,  /*       TEMP => ID */
+    0,  /*         LP => nothing */
+    0,  /*         RP => nothing */
+    0,  /*         AS => nothing */
+    0,  /*      COMMA => nothing */
+   60,  /*    WITHOUT => ID */
+   60,  /*      ABORT => ID */
+   60,  /*     ACTION => ID */
+   60,  /*      AFTER => ID */
+   60,  /*    ANALYZE => ID */
+   60,  /*        ASC => ID */
+   60,  /*     ATTACH => ID */
+   60,  /*     BEFORE => ID */
+   60,  /*         BY => ID */
+   60,  /*    CASCADE => ID */
+   60,  /*       CAST => ID */
+   60,  /*   CONFLICT => ID */
+   60,  /*   DATABASE => ID */
+   60,  /*       DESC => ID */
+   60,  /*     DETACH => ID */
+   60,  /*       EACH => ID */
+   60,  /*       FAIL => ID */
+    0,  /*         OR => nothing */
+    0,  /*        AND => nothing */
+    0,  /*         IS => nothing */
+    0,  /*      ISNOT => nothing */
+   60,  /*      MATCH => ID */
+   60,  /*    LIKE_KW => ID */
+    0,  /*    BETWEEN => nothing */
+    0,  /*         IN => nothing */
+    0,  /*     ISNULL => nothing */
+    0,  /*    NOTNULL => nothing */
+    0,  /*         NE => nothing */
+    0,  /*         EQ => nothing */
+    0,  /*         GT => nothing */
+    0,  /*         LE => nothing */
+    0,  /*         LT => nothing */
+    0,  /*         GE => nothing */
+    0,  /*     ESCAPE => nothing */
+    0,  /*         ID => nothing */
+   60,  /*   COLUMNKW => ID */
+   60,  /*         DO => ID */
+   60,  /*        FOR => ID */
+   60,  /*     IGNORE => ID */
+   60,  /*  INITIALLY => ID */
+   60,  /*    INSTEAD => ID */
+   60,  /*         NO => ID */
+   60,  /*        KEY => ID */
+   60,  /*         OF => ID */
+   60,  /*     OFFSET => ID */
+   60,  /*     PRAGMA => ID */
+   60,  /*      RAISE => ID */
+   60,  /*  RECURSIVE => ID */
+   60,  /*    REPLACE => ID */
+   60,  /*   RESTRICT => ID */
+   60,  /*        ROW => ID */
+   60,  /*       ROWS => ID */
+   60,  /*    TRIGGER => ID */
+   60,  /*     VACUUM => ID */
+   60,  /*       VIEW => ID */
+   60,  /*    VIRTUAL => ID */
+   60,  /*       WITH => ID */
+   60,  /*      NULLS => ID */
+   60,  /*      FIRST => ID */
+   60,  /*       LAST => ID */
+   60,  /*    CURRENT => ID */
+   60,  /*  FOLLOWING => ID */
+   60,  /*  PARTITION => ID */
+   60,  /*  PRECEDING => ID */
+   60,  /*      RANGE => ID */
+   60,  /*  UNBOUNDED => ID */
+   60,  /*    EXCLUDE => ID */
+   60,  /*     GROUPS => ID */
+   60,  /*     OTHERS => ID */
+   60,  /*       TIES => ID */
+   60,  /*  GENERATED => ID */
+   60,  /*     ALWAYS => ID */
+   60,  /* MATERIALIZED => ID */
+   60,  /*    REINDEX => ID */
+   60,  /*     RENAME => ID */
+   60,  /*   CTIME_KW => ID */
+    0,  /*        ANY => nothing */
+    0,  /*     BITAND => nothing */
+    0,  /*      BITOR => nothing */
+    0,  /*     LSHIFT => nothing */
+    0,  /*     RSHIFT => nothing */
+    0,  /*       PLUS => nothing */
+    0,  /*      MINUS => nothing */
+    0,  /*       STAR => nothing */
+    0,  /*      SLASH => nothing */
+    0,  /*        REM => nothing */
+    0,  /*     CONCAT => nothing */
+    0,  /*        PTR => nothing */
+    0,  /*    COLLATE => nothing */
+    0,  /*     BITNOT => nothing */
+    0,  /*         ON => nothing */
+    0,  /*    INDEXED => nothing */
+    0,  /*     STRING => nothing */
+    0,  /*    JOIN_KW => nothing */
+    0,  /* CONSTRAINT => nothing */
+    0,  /*    DEFAULT => nothing */
+    0,  /*       NULL => nothing */
+    0,  /*    PRIMARY => nothing */
+    0,  /*     UNIQUE => nothing */
+    0,  /*      CHECK => nothing */
+    0,  /* REFERENCES => nothing */
+    0,  /*   AUTOINCR => nothing */
+    0,  /*     INSERT => nothing */
+    0,  /*     DELETE => nothing */
+    0,  /*     UPDATE => nothing */
+    0,  /*        SET => nothing */
+    0,  /* DEFERRABLE => nothing */
+    0,  /*    FOREIGN => nothing */
+    0,  /*       DROP => nothing */
+    0,  /*      UNION => nothing */
+    0,  /*        ALL => nothing */
+    0,  /*     EXCEPT => nothing */
+    0,  /*  INTERSECT => nothing */
+    0,  /*     SELECT => nothing */
+    0,  /*     VALUES => nothing */
+    0,  /*   DISTINCT => nothing */
+    0,  /*        DOT => nothing */
+    0,  /*       FROM => nothing */
+    0,  /*       JOIN => nothing */
+    0,  /*      USING => nothing */
+    0,  /*      ORDER => nothing */
+    0,  /*      GROUP => nothing */
+    0,  /*     HAVING => nothing */
+    0,  /*      LIMIT => nothing */
+    0,  /*      WHERE => nothing */
+    0,  /*  RETURNING => nothing */
+    0,  /*       INTO => nothing */
+    0,  /*    NOTHING => nothing */
+    0,  /*      FLOAT => nothing */
+    0,  /*       BLOB => nothing */
+    0,  /*    INTEGER => nothing */
+    0,  /*   VARIABLE => nothing */
+    0,  /*       CASE => nothing */
+    0,  /*       WHEN => nothing */
+    0,  /*       THEN => nothing */
+    0,  /*       ELSE => nothing */
+    0,  /*      INDEX => nothing */
+    0,  /*      ALTER => nothing */
+    0,  /*        ADD => nothing */
+    0,  /*     WINDOW => nothing */
+    0,  /*       OVER => nothing */
+    0,  /*     FILTER => nothing */
+    0,  /*     COLUMN => nothing */
+    0,  /* AGG_FUNCTION => nothing */
+    0,  /* AGG_COLUMN => nothing */
+    0,  /*  TRUEFALSE => nothing */
+    0,  /*   FUNCTION => nothing */
+    0,  /*      UPLUS => nothing */
+    0,  /*     UMINUS => nothing */
+    0,  /*      TRUTH => nothing */
+    0,  /*   REGISTER => nothing */
+    0,  /*     VECTOR => nothing */
+    0,  /* SELECT_COLUMN => nothing */
+    0,  /* IF_NULL_ROW => nothing */
+    0,  /*   ASTERISK => nothing */
+    0,  /*       SPAN => nothing */
+    0,  /*      ERROR => nothing */
+    0,  /*    QNUMBER => nothing */
+    0,  /*      SPACE => nothing */
+    0,  /*    COMMENT => nothing */
+    0,  /*    ILLEGAL => nothing */
+};
+#endif /* YYFALLBACK */
+
+/* The following structure represents a single element of the
+** parser's stack.  Information stored includes:
+**
+**   +  The state number for the parser at this level of the stack.
+**
+**   +  The value of the token stored at this level of the stack.
+**      (In other words, the "major" token.)
+**
+**   +  The semantic value stored at this level of the stack.  This is
+**      the information used by the action routines in the grammar.
+**      It is sometimes called the "minor" token.
+**
+** After the "shift" half of a SHIFTREDUCE action, the stateno field
+** actually contains the reduce action for the second half of the
+** SHIFTREDUCE.
+*/
+struct yyStackEntry {
+  YYACTIONTYPE stateno;  /* The state-number, or reduce action in SHIFTREDUCE */
+  YYCODETYPE major;      /* The major token value.  This is the code
+                         ** number for the token at this stack level */
+  YYMINORTYPE minor;     /* The user-supplied minor token value.  This
+                         ** is the value of the token  */
+};
+typedef struct yyStackEntry yyStackEntry;
+
+/* The state of the parser is completely contained in an instance of
+** the following structure */
+struct yyParser {
+  yyStackEntry *yytos;          /* Pointer to top element of the stack */
+#ifdef YYTRACKMAXSTACKDEPTH
+  int yyhwm;                    /* High-water mark of the stack */
+#endif
+#ifndef YYNOERRORRECOVERY
+  int yyerrcnt;                 /* Shifts left before out of the error */
+#endif
+  sqlite3ParserARG_SDECL                /* A place to hold %extra_argument */
+  sqlite3ParserCTX_SDECL                /* A place to hold %extra_context */
+  yyStackEntry *yystackEnd;           /* Last entry in the stack */
+  yyStackEntry *yystack;              /* The parser stack */
+  yyStackEntry yystk0[YYSTACKDEPTH];  /* Initial stack space */
+};
+typedef struct yyParser yyParser;
+
+/* #include <assert.h> */
+#ifndef NDEBUG
+/* #include <stdio.h> */
+static FILE *yyTraceFILE = 0;
+static char *yyTracePrompt = 0;
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/*
+** Turn parser tracing on by giving a stream to which to write the trace
+** and a prompt to preface each trace message.  Tracing is turned off
+** by making either argument NULL
+**
+** Inputs:
+** <ul>
+** <li> A FILE* to which trace output should be written.
+**      If NULL, then tracing is turned off.
+** <li> A prefix string written at the beginning of every
+**      line of trace output.  If NULL, then tracing is
+**      turned off.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+SQLITE_PRIVATE void sqlite3ParserTrace(FILE *TraceFILE, char *zTracePrompt){
+  yyTraceFILE = TraceFILE;
+  yyTracePrompt = zTracePrompt;
+  if( yyTraceFILE==0 ) yyTracePrompt = 0;
+  else if( yyTracePrompt==0 ) yyTraceFILE = 0;
+}
+#endif /* NDEBUG */
+
+#if defined(YYCOVERAGE) || !defined(NDEBUG)
+/* For tracing shifts, the names of all terminals and nonterminals
+** are required.  The following table supplies these names */
+static const char *const yyTokenName[] = {
+  /*    0 */ "$",
+  /*    1 */ "SEMI",
+  /*    2 */ "EXPLAIN",
+  /*    3 */ "QUERY",
+  /*    4 */ "PLAN",
+  /*    5 */ "BEGIN",
+  /*    6 */ "TRANSACTION",
+  /*    7 */ "DEFERRED",
+  /*    8 */ "IMMEDIATE",
+  /*    9 */ "EXCLUSIVE",
+  /*   10 */ "COMMIT",
+  /*   11 */ "END",
+  /*   12 */ "ROLLBACK",
+  /*   13 */ "SAVEPOINT",
+  /*   14 */ "RELEASE",
+  /*   15 */ "TO",
+  /*   16 */ "TABLE",
+  /*   17 */ "CREATE",
+  /*   18 */ "IF",
+  /*   19 */ "NOT",
+  /*   20 */ "EXISTS",
+  /*   21 */ "TEMP",
+  /*   22 */ "LP",
+  /*   23 */ "RP",
+  /*   24 */ "AS",
+  /*   25 */ "COMMA",
+  /*   26 */ "WITHOUT",
+  /*   27 */ "ABORT",
+  /*   28 */ "ACTION",
+  /*   29 */ "AFTER",
+  /*   30 */ "ANALYZE",
+  /*   31 */ "ASC",
+  /*   32 */ "ATTACH",
+  /*   33 */ "BEFORE",
+  /*   34 */ "BY",
+  /*   35 */ "CASCADE",
+  /*   36 */ "CAST",
+  /*   37 */ "CONFLICT",
+  /*   38 */ "DATABASE",
+  /*   39 */ "DESC",
+  /*   40 */ "DETACH",
+  /*   41 */ "EACH",
+  /*   42 */ "FAIL",
+  /*   43 */ "OR",
+  /*   44 */ "AND",
+  /*   45 */ "IS",
+  /*   46 */ "ISNOT",
+  /*   47 */ "MATCH",
+  /*   48 */ "LIKE_KW",
+  /*   49 */ "BETWEEN",
+  /*   50 */ "IN",
+  /*   51 */ "ISNULL",
+  /*   52 */ "NOTNULL",
+  /*   53 */ "NE",
+  /*   54 */ "EQ",
+  /*   55 */ "GT",
+  /*   56 */ "LE",
+  /*   57 */ "LT",
+  /*   58 */ "GE",
+  /*   59 */ "ESCAPE",
+  /*   60 */ "ID",
+  /*   61 */ "COLUMNKW",
+  /*   62 */ "DO",
+  /*   63 */ "FOR",
+  /*   64 */ "IGNORE",
+  /*   65 */ "INITIALLY",
+  /*   66 */ "INSTEAD",
+  /*   67 */ "NO",
+  /*   68 */ "KEY",
+  /*   69 */ "OF",
+  /*   70 */ "OFFSET",
+  /*   71 */ "PRAGMA",
+  /*   72 */ "RAISE",
+  /*   73 */ "RECURSIVE",
+  /*   74 */ "REPLACE",
+  /*   75 */ "RESTRICT",
+  /*   76 */ "ROW",
+  /*   77 */ "ROWS",
+  /*   78 */ "TRIGGER",
+  /*   79 */ "VACUUM",
+  /*   80 */ "VIEW",
+  /*   81 */ "VIRTUAL",
+  /*   82 */ "WITH",
+  /*   83 */ "NULLS",
+  /*   84 */ "FIRST",
+  /*   85 */ "LAST",
+  /*   86 */ "CURRENT",
+  /*   87 */ "FOLLOWING",
+  /*   88 */ "PARTITION",
+  /*   89 */ "PRECEDING",
+  /*   90 */ "RANGE",
+  /*   91 */ "UNBOUNDED",
+  /*   92 */ "EXCLUDE",
+  /*   93 */ "GROUPS",
+  /*   94 */ "OTHERS",
+  /*   95 */ "TIES",
+  /*   96 */ "GENERATED",
+  /*   97 */ "ALWAYS",
+  /*   98 */ "MATERIALIZED",
+  /*   99 */ "REINDEX",
+  /*  100 */ "RENAME",
+  /*  101 */ "CTIME_KW",
+  /*  102 */ "ANY",
+  /*  103 */ "BITAND",
+  /*  104 */ "BITOR",
+  /*  105 */ "LSHIFT",
+  /*  106 */ "RSHIFT",
+  /*  107 */ "PLUS",
+  /*  108 */ "MINUS",
+  /*  109 */ "STAR",
+  /*  110 */ "SLASH",
+  /*  111 */ "REM",
+  /*  112 */ "CONCAT",
+  /*  113 */ "PTR",
+  /*  114 */ "COLLATE",
+  /*  115 */ "BITNOT",
+  /*  116 */ "ON",
+  /*  117 */ "INDEXED",
+  /*  118 */ "STRING",
+  /*  119 */ "JOIN_KW",
+  /*  120 */ "CONSTRAINT",
+  /*  121 */ "DEFAULT",
+  /*  122 */ "NULL",
+  /*  123 */ "PRIMARY",
+  /*  124 */ "UNIQUE",
+  /*  125 */ "CHECK",
+  /*  126 */ "REFERENCES",
+  /*  127 */ "AUTOINCR",
+  /*  128 */ "INSERT",
+  /*  129 */ "DELETE",
+  /*  130 */ "UPDATE",
+  /*  131 */ "SET",
+  /*  132 */ "DEFERRABLE",
+  /*  133 */ "FOREIGN",
+  /*  134 */ "DROP",
+  /*  135 */ "UNION",
+  /*  136 */ "ALL",
+  /*  137 */ "EXCEPT",
+  /*  138 */ "INTERSECT",
+  /*  139 */ "SELECT",
+  /*  140 */ "VALUES",
+  /*  141 */ "DISTINCT",
+  /*  142 */ "DOT",
+  /*  143 */ "FROM",
+  /*  144 */ "JOIN",
+  /*  145 */ "USING",
+  /*  146 */ "ORDER",
+  /*  147 */ "GROUP",
+  /*  148 */ "HAVING",
+  /*  149 */ "LIMIT",
+  /*  150 */ "WHERE",
+  /*  151 */ "RETURNING",
+  /*  152 */ "INTO",
+  /*  153 */ "NOTHING",
+  /*  154 */ "FLOAT",
+  /*  155 */ "BLOB",
+  /*  156 */ "INTEGER",
+  /*  157 */ "VARIABLE",
+  /*  158 */ "CASE",
+  /*  159 */ "WHEN",
+  /*  160 */ "THEN",
+  /*  161 */ "ELSE",
+  /*  162 */ "INDEX",
+  /*  163 */ "ALTER",
+  /*  164 */ "ADD",
+  /*  165 */ "WINDOW",
+  /*  166 */ "OVER",
+  /*  167 */ "FILTER",
+  /*  168 */ "COLUMN",
+  /*  169 */ "AGG_FUNCTION",
+  /*  170 */ "AGG_COLUMN",
+  /*  171 */ "TRUEFALSE",
+  /*  172 */ "FUNCTION",
+  /*  173 */ "UPLUS",
+  /*  174 */ "UMINUS",
+  /*  175 */ "TRUTH",
+  /*  176 */ "REGISTER",
+  /*  177 */ "VECTOR",
+  /*  178 */ "SELECT_COLUMN",
+  /*  179 */ "IF_NULL_ROW",
+  /*  180 */ "ASTERISK",
+  /*  181 */ "SPAN",
+  /*  182 */ "ERROR",
+  /*  183 */ "QNUMBER",
+  /*  184 */ "SPACE",
+  /*  185 */ "COMMENT",
+  /*  186 */ "ILLEGAL",
+  /*  187 */ "input",
+  /*  188 */ "cmdlist",
+  /*  189 */ "ecmd",
+  /*  190 */ "cmdx",
+  /*  191 */ "explain",
+  /*  192 */ "cmd",
+  /*  193 */ "transtype",
+  /*  194 */ "trans_opt",
+  /*  195 */ "nm",
+  /*  196 */ "savepoint_opt",
+  /*  197 */ "create_table",
+  /*  198 */ "create_table_args",
+  /*  199 */ "createkw",
+  /*  200 */ "temp",
+  /*  201 */ "ifnotexists",
+  /*  202 */ "dbnm",
+  /*  203 */ "columnlist",
+  /*  204 */ "conslist_opt",
+  /*  205 */ "table_option_set",
+  /*  206 */ "select",
+  /*  207 */ "table_option",
+  /*  208 */ "columnname",
+  /*  209 */ "carglist",
+  /*  210 */ "typetoken",
+  /*  211 */ "typename",
+  /*  212 */ "signed",
+  /*  213 */ "plus_num",
+  /*  214 */ "minus_num",
+  /*  215 */ "scanpt",
+  /*  216 */ "scantok",
+  /*  217 */ "ccons",
+  /*  218 */ "term",
+  /*  219 */ "expr",
+  /*  220 */ "onconf",
+  /*  221 */ "sortorder",
+  /*  222 */ "autoinc",
+  /*  223 */ "eidlist_opt",
+  /*  224 */ "refargs",
+  /*  225 */ "defer_subclause",
+  /*  226 */ "generated",
+  /*  227 */ "refarg",
+  /*  228 */ "refact",
+  /*  229 */ "init_deferred_pred_opt",
+  /*  230 */ "conslist",
+  /*  231 */ "tconscomma",
+  /*  232 */ "tcons",
+  /*  233 */ "sortlist",
+  /*  234 */ "eidlist",
+  /*  235 */ "defer_subclause_opt",
+  /*  236 */ "orconf",
+  /*  237 */ "resolvetype",
+  /*  238 */ "raisetype",
+  /*  239 */ "ifexists",
+  /*  240 */ "fullname",
+  /*  241 */ "selectnowith",
+  /*  242 */ "oneselect",
+  /*  243 */ "wqlist",
+  /*  244 */ "multiselect_op",
+  /*  245 */ "distinct",
+  /*  246 */ "selcollist",
+  /*  247 */ "from",
+  /*  248 */ "where_opt",
+  /*  249 */ "groupby_opt",
+  /*  250 */ "having_opt",
+  /*  251 */ "orderby_opt",
+  /*  252 */ "limit_opt",
+  /*  253 */ "window_clause",
+  /*  254 */ "values",
+  /*  255 */ "nexprlist",
+  /*  256 */ "mvalues",
+  /*  257 */ "sclp",
+  /*  258 */ "as",
+  /*  259 */ "seltablist",
+  /*  260 */ "stl_prefix",
+  /*  261 */ "joinop",
+  /*  262 */ "on_using",
+  /*  263 */ "indexed_by",
+  /*  264 */ "exprlist",
+  /*  265 */ "xfullname",
+  /*  266 */ "idlist",
+  /*  267 */ "indexed_opt",
+  /*  268 */ "nulls",
+  /*  269 */ "with",
+  /*  270 */ "where_opt_ret",
+  /*  271 */ "setlist",
+  /*  272 */ "insert_cmd",
+  /*  273 */ "idlist_opt",
+  /*  274 */ "upsert",
+  /*  275 */ "returning",
+  /*  276 */ "filter_over",
+  /*  277 */ "likeop",
+  /*  278 */ "between_op",
+  /*  279 */ "in_op",
+  /*  280 */ "paren_exprlist",
+  /*  281 */ "case_operand",
+  /*  282 */ "case_exprlist",
+  /*  283 */ "case_else",
+  /*  284 */ "uniqueflag",
+  /*  285 */ "collate",
+  /*  286 */ "vinto",
+  /*  287 */ "nmnum",
+  /*  288 */ "trigger_decl",
+  /*  289 */ "trigger_cmd_list",
+  /*  290 */ "trigger_time",
+  /*  291 */ "trigger_event",
+  /*  292 */ "foreach_clause",
+  /*  293 */ "when_clause",
+  /*  294 */ "trigger_cmd",
+  /*  295 */ "trnm",
+  /*  296 */ "tridxby",
+  /*  297 */ "database_kw_opt",
+  /*  298 */ "key_opt",
+  /*  299 */ "add_column_fullname",
+  /*  300 */ "kwcolumn_opt",
+  /*  301 */ "create_vtab",
+  /*  302 */ "vtabarglist",
+  /*  303 */ "vtabarg",
+  /*  304 */ "vtabargtoken",
+  /*  305 */ "lp",
+  /*  306 */ "anylist",
+  /*  307 */ "wqitem",
+  /*  308 */ "wqas",
+  /*  309 */ "withnm",
+  /*  310 */ "windowdefn_list",
+  /*  311 */ "windowdefn",
+  /*  312 */ "window",
+  /*  313 */ "frame_opt",
+  /*  314 */ "part_opt",
+  /*  315 */ "filter_clause",
+  /*  316 */ "over_clause",
+  /*  317 */ "range_or_rows",
+  /*  318 */ "frame_bound",
+  /*  319 */ "frame_bound_s",
+  /*  320 */ "frame_bound_e",
+  /*  321 */ "frame_exclude_opt",
+  /*  322 */ "frame_exclude",
+};
+#endif /* defined(YYCOVERAGE) || !defined(NDEBUG) */
+
+#ifndef NDEBUG
+/* For tracing reduce actions, the names of all rules are required.
+*/
+static const char *const yyRuleName[] = {
+ /*   0 */ "explain ::= EXPLAIN",
+ /*   1 */ "explain ::= EXPLAIN QUERY PLAN",
+ /*   2 */ "cmdx ::= cmd",
+ /*   3 */ "cmd ::= BEGIN transtype trans_opt",
+ /*   4 */ "transtype ::=",
+ /*   5 */ "transtype ::= DEFERRED",
+ /*   6 */ "transtype ::= IMMEDIATE",
+ /*   7 */ "transtype ::= EXCLUSIVE",
+ /*   8 */ "cmd ::= COMMIT|END trans_opt",
+ /*   9 */ "cmd ::= ROLLBACK trans_opt",
+ /*  10 */ "cmd ::= SAVEPOINT nm",
+ /*  11 */ "cmd ::= RELEASE savepoint_opt nm",
+ /*  12 */ "cmd ::= ROLLBACK trans_opt TO savepoint_opt nm",
+ /*  13 */ "create_table ::= createkw temp TABLE ifnotexists nm dbnm",
+ /*  14 */ "createkw ::= CREATE",
+ /*  15 */ "ifnotexists ::=",
+ /*  16 */ "ifnotexists ::= IF NOT EXISTS",
+ /*  17 */ "temp ::= TEMP",
+ /*  18 */ "temp ::=",
+ /*  19 */ "create_table_args ::= LP columnlist conslist_opt RP table_option_set",
+ /*  20 */ "create_table_args ::= AS select",
+ /*  21 */ "table_option_set ::=",
+ /*  22 */ "table_option_set ::= table_option_set COMMA table_option",
+ /*  23 */ "table_option ::= WITHOUT nm",
+ /*  24 */ "table_option ::= nm",
+ /*  25 */ "columnname ::= nm typetoken",
+ /*  26 */ "typetoken ::=",
+ /*  27 */ "typetoken ::= typename LP signed RP",
+ /*  28 */ "typetoken ::= typename LP signed COMMA signed RP",
+ /*  29 */ "typename ::= typename ID|STRING",
+ /*  30 */ "scanpt ::=",
+ /*  31 */ "scantok ::=",
+ /*  32 */ "ccons ::= CONSTRAINT nm",
+ /*  33 */ "ccons ::= DEFAULT scantok term",
+ /*  34 */ "ccons ::= DEFAULT LP expr RP",
+ /*  35 */ "ccons ::= DEFAULT PLUS scantok term",
+ /*  36 */ "ccons ::= DEFAULT MINUS scantok term",
+ /*  37 */ "ccons ::= DEFAULT scantok ID|INDEXED",
+ /*  38 */ "ccons ::= NOT NULL onconf",
+ /*  39 */ "ccons ::= PRIMARY KEY sortorder onconf autoinc",
+ /*  40 */ "ccons ::= UNIQUE onconf",
+ /*  41 */ "ccons ::= CHECK LP expr RP",
+ /*  42 */ "ccons ::= REFERENCES nm eidlist_opt refargs",
+ /*  43 */ "ccons ::= defer_subclause",
+ /*  44 */ "ccons ::= COLLATE ID|STRING",
+ /*  45 */ "generated ::= LP expr RP",
+ /*  46 */ "generated ::= LP expr RP ID",
+ /*  47 */ "autoinc ::=",
+ /*  48 */ "autoinc ::= AUTOINCR",
+ /*  49 */ "refargs ::=",
+ /*  50 */ "refargs ::= refargs refarg",
+ /*  51 */ "refarg ::= MATCH nm",
+ /*  52 */ "refarg ::= ON INSERT refact",
+ /*  53 */ "refarg ::= ON DELETE refact",
+ /*  54 */ "refarg ::= ON UPDATE refact",
+ /*  55 */ "refact ::= SET NULL",
+ /*  56 */ "refact ::= SET DEFAULT",
+ /*  57 */ "refact ::= CASCADE",
+ /*  58 */ "refact ::= RESTRICT",
+ /*  59 */ "refact ::= NO ACTION",
+ /*  60 */ "defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt",
+ /*  61 */ "defer_subclause ::= DEFERRABLE init_deferred_pred_opt",
+ /*  62 */ "init_deferred_pred_opt ::=",
+ /*  63 */ "init_deferred_pred_opt ::= INITIALLY DEFERRED",
+ /*  64 */ "init_deferred_pred_opt ::= INITIALLY IMMEDIATE",
+ /*  65 */ "conslist_opt ::=",
+ /*  66 */ "tconscomma ::= COMMA",
+ /*  67 */ "tcons ::= CONSTRAINT nm",
+ /*  68 */ "tcons ::= PRIMARY KEY LP sortlist autoinc RP onconf",
+ /*  69 */ "tcons ::= UNIQUE LP sortlist RP onconf",
+ /*  70 */ "tcons ::= CHECK LP expr RP onconf",
+ /*  71 */ "tcons ::= FOREIGN KEY LP eidlist RP REFERENCES nm eidlist_opt refargs defer_subclause_opt",
+ /*  72 */ "defer_subclause_opt ::=",
+ /*  73 */ "onconf ::=",
+ /*  74 */ "onconf ::= ON CONFLICT resolvetype",
+ /*  75 */ "orconf ::=",
+ /*  76 */ "orconf ::= OR resolvetype",
+ /*  77 */ "resolvetype ::= IGNORE",
+ /*  78 */ "resolvetype ::= REPLACE",
+ /*  79 */ "cmd ::= DROP TABLE ifexists fullname",
+ /*  80 */ "ifexists ::= IF EXISTS",
+ /*  81 */ "ifexists ::=",
+ /*  82 */ "cmd ::= createkw temp VIEW ifnotexists nm dbnm eidlist_opt AS select",
+ /*  83 */ "cmd ::= DROP VIEW ifexists fullname",
+ /*  84 */ "cmd ::= select",
+ /*  85 */ "select ::= WITH wqlist selectnowith",
+ /*  86 */ "select ::= WITH RECURSIVE wqlist selectnowith",
+ /*  87 */ "select ::= selectnowith",
+ /*  88 */ "selectnowith ::= selectnowith multiselect_op oneselect",
+ /*  89 */ "multiselect_op ::= UNION",
+ /*  90 */ "multiselect_op ::= UNION ALL",
+ /*  91 */ "multiselect_op ::= EXCEPT|INTERSECT",
+ /*  92 */ "oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt",
+ /*  93 */ "oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt window_clause orderby_opt limit_opt",
+ /*  94 */ "values ::= VALUES LP nexprlist RP",
+ /*  95 */ "oneselect ::= mvalues",
+ /*  96 */ "mvalues ::= values COMMA LP nexprlist RP",
+ /*  97 */ "mvalues ::= mvalues COMMA LP nexprlist RP",
+ /*  98 */ "distinct ::= DISTINCT",
+ /*  99 */ "distinct ::= ALL",
+ /* 100 */ "distinct ::=",
+ /* 101 */ "sclp ::=",
+ /* 102 */ "selcollist ::= sclp scanpt expr scanpt as",
+ /* 103 */ "selcollist ::= sclp scanpt STAR",
+ /* 104 */ "selcollist ::= sclp scanpt nm DOT STAR",
+ /* 105 */ "as ::= AS nm",
+ /* 106 */ "as ::=",
+ /* 107 */ "from ::=",
+ /* 108 */ "from ::= FROM seltablist",
+ /* 109 */ "stl_prefix ::= seltablist joinop",
+ /* 110 */ "stl_prefix ::=",
+ /* 111 */ "seltablist ::= stl_prefix nm dbnm as on_using",
+ /* 112 */ "seltablist ::= stl_prefix nm dbnm as indexed_by on_using",
+ /* 113 */ "seltablist ::= stl_prefix nm dbnm LP exprlist RP as on_using",
+ /* 114 */ "seltablist ::= stl_prefix LP select RP as on_using",
+ /* 115 */ "seltablist ::= stl_prefix LP seltablist RP as on_using",
+ /* 116 */ "dbnm ::=",
+ /* 117 */ "dbnm ::= DOT nm",
+ /* 118 */ "fullname ::= nm",
+ /* 119 */ "fullname ::= nm DOT nm",
+ /* 120 */ "xfullname ::= nm",
+ /* 121 */ "xfullname ::= nm DOT nm",
+ /* 122 */ "xfullname ::= nm DOT nm AS nm",
+ /* 123 */ "xfullname ::= nm AS nm",
+ /* 124 */ "joinop ::= COMMA|JOIN",
+ /* 125 */ "joinop ::= JOIN_KW JOIN",
+ /* 126 */ "joinop ::= JOIN_KW nm JOIN",
+ /* 127 */ "joinop ::= JOIN_KW nm nm JOIN",
+ /* 128 */ "on_using ::= ON expr",
+ /* 129 */ "on_using ::= USING LP idlist RP",
+ /* 130 */ "on_using ::=",
+ /* 131 */ "indexed_opt ::=",
+ /* 132 */ "indexed_by ::= INDEXED BY nm",
+ /* 133 */ "indexed_by ::= NOT INDEXED",
+ /* 134 */ "orderby_opt ::=",
+ /* 135 */ "orderby_opt ::= ORDER BY sortlist",
+ /* 136 */ "sortlist ::= sortlist COMMA expr sortorder nulls",
+ /* 137 */ "sortlist ::= expr sortorder nulls",
+ /* 138 */ "sortorder ::= ASC",
+ /* 139 */ "sortorder ::= DESC",
+ /* 140 */ "sortorder ::=",
+ /* 141 */ "nulls ::= NULLS FIRST",
+ /* 142 */ "nulls ::= NULLS LAST",
+ /* 143 */ "nulls ::=",
+ /* 144 */ "groupby_opt ::=",
+ /* 145 */ "groupby_opt ::= GROUP BY nexprlist",
+ /* 146 */ "having_opt ::=",
+ /* 147 */ "having_opt ::= HAVING expr",
+ /* 148 */ "limit_opt ::=",
+ /* 149 */ "limit_opt ::= LIMIT expr",
+ /* 150 */ "limit_opt ::= LIMIT expr OFFSET expr",
+ /* 151 */ "limit_opt ::= LIMIT expr COMMA expr",
+ /* 152 */ "cmd ::= with DELETE FROM xfullname indexed_opt where_opt_ret orderby_opt limit_opt",
+ /* 153 */ "where_opt ::=",
+ /* 154 */ "where_opt ::= WHERE expr",
+ /* 155 */ "where_opt_ret ::=",
+ /* 156 */ "where_opt_ret ::= WHERE expr",
+ /* 157 */ "where_opt_ret ::= RETURNING selcollist",
+ /* 158 */ "where_opt_ret ::= WHERE expr RETURNING selcollist",
+ /* 159 */ "cmd ::= with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret orderby_opt limit_opt",
+ /* 160 */ "setlist ::= setlist COMMA nm EQ expr",
+ /* 161 */ "setlist ::= setlist COMMA LP idlist RP EQ expr",
+ /* 162 */ "setlist ::= nm EQ expr",
+ /* 163 */ "setlist ::= LP idlist RP EQ expr",
+ /* 164 */ "cmd ::= with insert_cmd INTO xfullname idlist_opt select upsert",
+ /* 165 */ "cmd ::= with insert_cmd INTO xfullname idlist_opt DEFAULT VALUES returning",
+ /* 166 */ "upsert ::=",
+ /* 167 */ "upsert ::= RETURNING selcollist",
+ /* 168 */ "upsert ::= ON CONFLICT LP sortlist RP where_opt DO UPDATE SET setlist where_opt upsert",
+ /* 169 */ "upsert ::= ON CONFLICT LP sortlist RP where_opt DO NOTHING upsert",
+ /* 170 */ "upsert ::= ON CONFLICT DO NOTHING returning",
+ /* 171 */ "upsert ::= ON CONFLICT DO UPDATE SET setlist where_opt returning",
+ /* 172 */ "returning ::= RETURNING selcollist",
+ /* 173 */ "insert_cmd ::= INSERT orconf",
+ /* 174 */ "insert_cmd ::= REPLACE",
+ /* 175 */ "idlist_opt ::=",
+ /* 176 */ "idlist_opt ::= LP idlist RP",
+ /* 177 */ "idlist ::= idlist COMMA nm",
+ /* 178 */ "idlist ::= nm",
+ /* 179 */ "expr ::= LP expr RP",
+ /* 180 */ "expr ::= ID|INDEXED|JOIN_KW",
+ /* 181 */ "expr ::= nm DOT nm",
+ /* 182 */ "expr ::= nm DOT nm DOT nm",
+ /* 183 */ "term ::= NULL|FLOAT|BLOB",
+ /* 184 */ "term ::= STRING",
+ /* 185 */ "term ::= INTEGER",
+ /* 186 */ "expr ::= VARIABLE",
+ /* 187 */ "expr ::= expr COLLATE ID|STRING",
+ /* 188 */ "expr ::= CAST LP expr AS typetoken RP",
+ /* 189 */ "expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP",
+ /* 190 */ "expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP",
+ /* 191 */ "expr ::= ID|INDEXED|JOIN_KW LP STAR RP",
+ /* 192 */ "expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP filter_over",
+ /* 193 */ "expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP filter_over",
+ /* 194 */ "expr ::= ID|INDEXED|JOIN_KW LP STAR RP filter_over",
+ /* 195 */ "term ::= CTIME_KW",
+ /* 196 */ "expr ::= LP nexprlist COMMA expr RP",
+ /* 197 */ "expr ::= expr AND expr",
+ /* 198 */ "expr ::= expr OR expr",
+ /* 199 */ "expr ::= expr LT|GT|GE|LE expr",
+ /* 200 */ "expr ::= expr EQ|NE expr",
+ /* 201 */ "expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr",
+ /* 202 */ "expr ::= expr PLUS|MINUS expr",
+ /* 203 */ "expr ::= expr STAR|SLASH|REM expr",
+ /* 204 */ "expr ::= expr CONCAT expr",
+ /* 205 */ "likeop ::= NOT LIKE_KW|MATCH",
+ /* 206 */ "expr ::= expr likeop expr",
+ /* 207 */ "expr ::= expr likeop expr ESCAPE expr",
+ /* 208 */ "expr ::= expr ISNULL|NOTNULL",
+ /* 209 */ "expr ::= expr NOT NULL",
+ /* 210 */ "expr ::= expr IS expr",
+ /* 211 */ "expr ::= expr IS NOT expr",
+ /* 212 */ "expr ::= expr IS NOT DISTINCT FROM expr",
+ /* 213 */ "expr ::= expr IS DISTINCT FROM expr",
+ /* 214 */ "expr ::= NOT expr",
+ /* 215 */ "expr ::= BITNOT expr",
+ /* 216 */ "expr ::= PLUS|MINUS expr",
+ /* 217 */ "expr ::= expr PTR expr",
+ /* 218 */ "between_op ::= BETWEEN",
+ /* 219 */ "between_op ::= NOT BETWEEN",
+ /* 220 */ "expr ::= expr between_op expr AND expr",
+ /* 221 */ "in_op ::= IN",
+ /* 222 */ "in_op ::= NOT IN",
+ /* 223 */ "expr ::= expr in_op LP exprlist RP",
+ /* 224 */ "expr ::= LP select RP",
+ /* 225 */ "expr ::= expr in_op LP select RP",
+ /* 226 */ "expr ::= expr in_op nm dbnm paren_exprlist",
+ /* 227 */ "expr ::= EXISTS LP select RP",
+ /* 228 */ "expr ::= CASE case_operand case_exprlist case_else END",
+ /* 229 */ "case_exprlist ::= case_exprlist WHEN expr THEN expr",
+ /* 230 */ "case_exprlist ::= WHEN expr THEN expr",
+ /* 231 */ "case_else ::= ELSE expr",
+ /* 232 */ "case_else ::=",
+ /* 233 */ "case_operand ::=",
+ /* 234 */ "exprlist ::=",
+ /* 235 */ "nexprlist ::= nexprlist COMMA expr",
+ /* 236 */ "nexprlist ::= expr",
+ /* 237 */ "paren_exprlist ::=",
+ /* 238 */ "paren_exprlist ::= LP exprlist RP",
+ /* 239 */ "cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP sortlist RP where_opt",
+ /* 240 */ "uniqueflag ::= UNIQUE",
+ /* 241 */ "uniqueflag ::=",
+ /* 242 */ "eidlist_opt ::=",
+ /* 243 */ "eidlist_opt ::= LP eidlist RP",
+ /* 244 */ "eidlist ::= eidlist COMMA nm collate sortorder",
+ /* 245 */ "eidlist ::= nm collate sortorder",
+ /* 246 */ "collate ::=",
+ /* 247 */ "collate ::= COLLATE ID|STRING",
+ /* 248 */ "cmd ::= DROP INDEX ifexists fullname",
+ /* 249 */ "cmd ::= VACUUM vinto",
+ /* 250 */ "cmd ::= VACUUM nm vinto",
+ /* 251 */ "vinto ::= INTO expr",
+ /* 252 */ "vinto ::=",
+ /* 253 */ "cmd ::= PRAGMA nm dbnm",
+ /* 254 */ "cmd ::= PRAGMA nm dbnm EQ nmnum",
+ /* 255 */ "cmd ::= PRAGMA nm dbnm LP nmnum RP",
+ /* 256 */ "cmd ::= PRAGMA nm dbnm EQ minus_num",
+ /* 257 */ "cmd ::= PRAGMA nm dbnm LP minus_num RP",
+ /* 258 */ "plus_num ::= PLUS INTEGER|FLOAT",
+ /* 259 */ "minus_num ::= MINUS INTEGER|FLOAT",
+ /* 260 */ "cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END",
+ /* 261 */ "trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause",
+ /* 262 */ "trigger_time ::= BEFORE|AFTER",
+ /* 263 */ "trigger_time ::= INSTEAD OF",
+ /* 264 */ "trigger_time ::=",
+ /* 265 */ "trigger_event ::= DELETE|INSERT",
+ /* 266 */ "trigger_event ::= UPDATE",
+ /* 267 */ "trigger_event ::= UPDATE OF idlist",
+ /* 268 */ "when_clause ::=",
+ /* 269 */ "when_clause ::= WHEN expr",
+ /* 270 */ "trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI",
+ /* 271 */ "trigger_cmd_list ::= trigger_cmd SEMI",
+ /* 272 */ "trnm ::= nm DOT nm",
+ /* 273 */ "tridxby ::= INDEXED BY nm",
+ /* 274 */ "tridxby ::= NOT INDEXED",
+ /* 275 */ "trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist from where_opt scanpt",
+ /* 276 */ "trigger_cmd ::= scanpt insert_cmd INTO trnm idlist_opt select upsert scanpt",
+ /* 277 */ "trigger_cmd ::= DELETE FROM trnm tridxby where_opt scanpt",
+ /* 278 */ "trigger_cmd ::= scanpt select scanpt",
+ /* 279 */ "expr ::= RAISE LP IGNORE RP",
+ /* 280 */ "expr ::= RAISE LP raisetype COMMA expr RP",
+ /* 281 */ "raisetype ::= ROLLBACK",
+ /* 282 */ "raisetype ::= ABORT",
+ /* 283 */ "raisetype ::= FAIL",
+ /* 284 */ "cmd ::= DROP TRIGGER ifexists fullname",
+ /* 285 */ "cmd ::= ATTACH database_kw_opt expr AS expr key_opt",
+ /* 286 */ "cmd ::= DETACH database_kw_opt expr",
+ /* 287 */ "key_opt ::=",
+ /* 288 */ "key_opt ::= KEY expr",
+ /* 289 */ "cmd ::= REINDEX",
+ /* 290 */ "cmd ::= REINDEX nm dbnm",
+ /* 291 */ "cmd ::= ANALYZE",
+ /* 292 */ "cmd ::= ANALYZE nm dbnm",
+ /* 293 */ "cmd ::= ALTER TABLE fullname RENAME TO nm",
+ /* 294 */ "cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt columnname carglist",
+ /* 295 */ "cmd ::= ALTER TABLE fullname DROP kwcolumn_opt nm",
+ /* 296 */ "add_column_fullname ::= fullname",
+ /* 297 */ "cmd ::= ALTER TABLE fullname RENAME kwcolumn_opt nm TO nm",
+ /* 298 */ "cmd ::= create_vtab",
+ /* 299 */ "cmd ::= create_vtab LP vtabarglist RP",
+ /* 300 */ "create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm",
+ /* 301 */ "vtabarg ::=",
+ /* 302 */ "vtabargtoken ::= ANY",
+ /* 303 */ "vtabargtoken ::= lp anylist RP",
+ /* 304 */ "lp ::= LP",
+ /* 305 */ "with ::= WITH wqlist",
+ /* 306 */ "with ::= WITH RECURSIVE wqlist",
+ /* 307 */ "wqas ::= AS",
+ /* 308 */ "wqas ::= AS MATERIALIZED",
+ /* 309 */ "wqas ::= AS NOT MATERIALIZED",
+ /* 310 */ "wqitem ::= withnm eidlist_opt wqas LP select RP",
+ /* 311 */ "withnm ::= nm",
+ /* 312 */ "wqlist ::= wqitem",
+ /* 313 */ "wqlist ::= wqlist COMMA wqitem",
+ /* 314 */ "windowdefn_list ::= windowdefn_list COMMA windowdefn",
+ /* 315 */ "windowdefn ::= nm AS LP window RP",
+ /* 316 */ "window ::= PARTITION BY nexprlist orderby_opt frame_opt",
+ /* 317 */ "window ::= nm PARTITION BY nexprlist orderby_opt frame_opt",
+ /* 318 */ "window ::= ORDER BY sortlist frame_opt",
+ /* 319 */ "window ::= nm ORDER BY sortlist frame_opt",
+ /* 320 */ "window ::= nm frame_opt",
+ /* 321 */ "frame_opt ::=",
+ /* 322 */ "frame_opt ::= range_or_rows frame_bound_s frame_exclude_opt",
+ /* 323 */ "frame_opt ::= range_or_rows BETWEEN frame_bound_s AND frame_bound_e frame_exclude_opt",
+ /* 324 */ "range_or_rows ::= RANGE|ROWS|GROUPS",
+ /* 325 */ "frame_bound_s ::= frame_bound",
+ /* 326 */ "frame_bound_s ::= UNBOUNDED PRECEDING",
+ /* 327 */ "frame_bound_e ::= frame_bound",
+ /* 328 */ "frame_bound_e ::= UNBOUNDED FOLLOWING",
+ /* 329 */ "frame_bound ::= expr PRECEDING|FOLLOWING",
+ /* 330 */ "frame_bound ::= CURRENT ROW",
+ /* 331 */ "frame_exclude_opt ::=",
+ /* 332 */ "frame_exclude_opt ::= EXCLUDE frame_exclude",
+ /* 333 */ "frame_exclude ::= NO OTHERS",
+ /* 334 */ "frame_exclude ::= CURRENT ROW",
+ /* 335 */ "frame_exclude ::= GROUP|TIES",
+ /* 336 */ "window_clause ::= WINDOW windowdefn_list",
+ /* 337 */ "filter_over ::= filter_clause over_clause",
+ /* 338 */ "filter_over ::= over_clause",
+ /* 339 */ "filter_over ::= filter_clause",
+ /* 340 */ "over_clause ::= OVER LP window RP",
+ /* 341 */ "over_clause ::= OVER nm",
+ /* 342 */ "filter_clause ::= FILTER LP WHERE expr RP",
+ /* 343 */ "term ::= QNUMBER",
+ /* 344 */ "input ::= cmdlist",
+ /* 345 */ "cmdlist ::= cmdlist ecmd",
+ /* 346 */ "cmdlist ::= ecmd",
+ /* 347 */ "ecmd ::= SEMI",
+ /* 348 */ "ecmd ::= cmdx SEMI",
+ /* 349 */ "ecmd ::= explain cmdx SEMI",
+ /* 350 */ "trans_opt ::=",
+ /* 351 */ "trans_opt ::= TRANSACTION",
+ /* 352 */ "trans_opt ::= TRANSACTION nm",
+ /* 353 */ "savepoint_opt ::= SAVEPOINT",
+ /* 354 */ "savepoint_opt ::=",
+ /* 355 */ "cmd ::= create_table create_table_args",
+ /* 356 */ "table_option_set ::= table_option",
+ /* 357 */ "columnlist ::= columnlist COMMA columnname carglist",
+ /* 358 */ "columnlist ::= columnname carglist",
+ /* 359 */ "nm ::= ID|INDEXED|JOIN_KW",
+ /* 360 */ "nm ::= STRING",
+ /* 361 */ "typetoken ::= typename",
+ /* 362 */ "typename ::= ID|STRING",
+ /* 363 */ "signed ::= plus_num",
+ /* 364 */ "signed ::= minus_num",
+ /* 365 */ "carglist ::= carglist ccons",
+ /* 366 */ "carglist ::=",
+ /* 367 */ "ccons ::= NULL onconf",
+ /* 368 */ "ccons ::= GENERATED ALWAYS AS generated",
+ /* 369 */ "ccons ::= AS generated",
+ /* 370 */ "conslist_opt ::= COMMA conslist",
+ /* 371 */ "conslist ::= conslist tconscomma tcons",
+ /* 372 */ "conslist ::= tcons",
+ /* 373 */ "tconscomma ::=",
+ /* 374 */ "defer_subclause_opt ::= defer_subclause",
+ /* 375 */ "resolvetype ::= raisetype",
+ /* 376 */ "selectnowith ::= oneselect",
+ /* 377 */ "oneselect ::= values",
+ /* 378 */ "sclp ::= selcollist COMMA",
+ /* 379 */ "as ::= ID|STRING",
+ /* 380 */ "indexed_opt ::= indexed_by",
+ /* 381 */ "returning ::=",
+ /* 382 */ "expr ::= term",
+ /* 383 */ "likeop ::= LIKE_KW|MATCH",
+ /* 384 */ "case_operand ::= expr",
+ /* 385 */ "exprlist ::= nexprlist",
+ /* 386 */ "nmnum ::= plus_num",
+ /* 387 */ "nmnum ::= nm",
+ /* 388 */ "nmnum ::= ON",
+ /* 389 */ "nmnum ::= DELETE",
+ /* 390 */ "nmnum ::= DEFAULT",
+ /* 391 */ "plus_num ::= INTEGER|FLOAT",
+ /* 392 */ "foreach_clause ::=",
+ /* 393 */ "foreach_clause ::= FOR EACH ROW",
+ /* 394 */ "trnm ::= nm",
+ /* 395 */ "tridxby ::=",
+ /* 396 */ "database_kw_opt ::= DATABASE",
+ /* 397 */ "database_kw_opt ::=",
+ /* 398 */ "kwcolumn_opt ::=",
+ /* 399 */ "kwcolumn_opt ::= COLUMNKW",
+ /* 400 */ "vtabarglist ::= vtabarg",
+ /* 401 */ "vtabarglist ::= vtabarglist COMMA vtabarg",
+ /* 402 */ "vtabarg ::= vtabarg vtabargtoken",
+ /* 403 */ "anylist ::=",
+ /* 404 */ "anylist ::= anylist LP anylist RP",
+ /* 405 */ "anylist ::= anylist ANY",
+ /* 406 */ "with ::=",
+ /* 407 */ "windowdefn_list ::= windowdefn",
+ /* 408 */ "window ::= frame_opt",
+};
+#endif /* NDEBUG */
+
+
+#if YYGROWABLESTACK
+/*
+** Try to increase the size of the parser stack.  Return the number
+** of errors.  Return 0 on success.
+*/
+static int yyGrowStack(yyParser *p){
+  int oldSize = 1 + (int)(p->yystackEnd - p->yystack);
+  int newSize;
+  int idx;
+  yyStackEntry *pNew;
+
+  newSize = oldSize*2 + 100;
+  idx = (int)(p->yytos - p->yystack);
+  if( p->yystack==p->yystk0 ){
+    pNew = YYREALLOC(0, newSize*sizeof(pNew[0]));
+    if( pNew==0 ) return 1;
+    memcpy(pNew, p->yystack, oldSize*sizeof(pNew[0]));
+  }else{
+    pNew = YYREALLOC(p->yystack, newSize*sizeof(pNew[0]));
+    if( pNew==0 ) return 1;
+  }
+  p->yystack = pNew;
+  p->yytos = &p->yystack[idx];
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sStack grows from %d to %d entries.\n",
+            yyTracePrompt, oldSize, newSize);
+  }
+#endif
+  p->yystackEnd = &p->yystack[newSize-1];
+  return 0;
+}
+#endif /* YYGROWABLESTACK */
+
+#if !YYGROWABLESTACK
+/* For builds that do no have a growable stack, yyGrowStack always
+** returns an error.
+*/
+# define yyGrowStack(X) 1
+#endif
+
+/* Datatype of the argument to the memory allocated passed as the
+** second argument to sqlite3ParserAlloc() below.  This can be changed by
+** putting an appropriate #define in the %include section of the input
+** grammar.
+*/
+#ifndef YYMALLOCARGTYPE
+# define YYMALLOCARGTYPE size_t
+#endif
+
+/* Initialize a new parser that has already been allocated.
+*/
+SQLITE_PRIVATE void sqlite3ParserInit(void *yypRawParser sqlite3ParserCTX_PDECL){
+  yyParser *yypParser = (yyParser*)yypRawParser;
+  sqlite3ParserCTX_STORE
+#ifdef YYTRACKMAXSTACKDEPTH
+  yypParser->yyhwm = 0;
+#endif
+  yypParser->yystack = yypParser->yystk0;
+  yypParser->yystackEnd = &yypParser->yystack[YYSTACKDEPTH-1];
+#ifndef YYNOERRORRECOVERY
+  yypParser->yyerrcnt = -1;
+#endif
+  yypParser->yytos = yypParser->yystack;
+  yypParser->yystack[0].stateno = 0;
+  yypParser->yystack[0].major = 0;
+}
+
+#ifndef sqlite3Parser_ENGINEALWAYSONSTACK
+/*
+** This function allocates a new parser.
+** The only argument is a pointer to a function which works like
+** malloc.
+**
+** Inputs:
+** A pointer to the function used to allocate memory.
+**
+** Outputs:
+** A pointer to a parser.  This pointer is used in subsequent calls
+** to sqlite3Parser and sqlite3ParserFree.
+*/
+SQLITE_PRIVATE void *sqlite3ParserAlloc(void *(*mallocProc)(YYMALLOCARGTYPE) sqlite3ParserCTX_PDECL){
+  yyParser *yypParser;
+  yypParser = (yyParser*)(*mallocProc)( (YYMALLOCARGTYPE)sizeof(yyParser) );
+  if( yypParser ){
+    sqlite3ParserCTX_STORE
+    sqlite3ParserInit(yypParser sqlite3ParserCTX_PARAM);
+  }
+  return (void*)yypParser;
+}
+#endif /* sqlite3Parser_ENGINEALWAYSONSTACK */
+
+
+/* The following function deletes the "minor type" or semantic value
+** associated with a symbol.  The symbol can be either a terminal
+** or nonterminal. "yymajor" is the symbol code, and "yypminor" is
+** a pointer to the value to be deleted.  The code used to do the
+** deletions is derived from the %destructor and/or %token_destructor
+** directives of the input grammar.
+*/
+static void yy_destructor(
+  yyParser *yypParser,    /* The parser */
+  YYCODETYPE yymajor,     /* Type code for object to destroy */
+  YYMINORTYPE *yypminor   /* The object to be destroyed */
+){
+  sqlite3ParserARG_FETCH
+  sqlite3ParserCTX_FETCH
+  switch( yymajor ){
+    /* Here is inserted the actions which take place when a
+    ** terminal or non-terminal is destroyed.  This can happen
+    ** when the symbol is popped from the stack during a
+    ** reduce or during error processing or when a parser is
+    ** being destroyed before it is finished parsing.
+    **
+    ** Note: during a reduce, the only symbols destroyed are those
+    ** which appear on the RHS of the rule, but which are *not* used
+    ** inside the C code.
+    */
+/********* Begin destructor definitions ***************************************/
+    case 206: /* select */
+    case 241: /* selectnowith */
+    case 242: /* oneselect */
+    case 254: /* values */
+    case 256: /* mvalues */
+{
+sqlite3SelectDelete(pParse->db, (yypminor->yy637));
+}
+      break;
+    case 218: /* term */
+    case 219: /* expr */
+    case 248: /* where_opt */
+    case 250: /* having_opt */
+    case 270: /* where_opt_ret */
+    case 281: /* case_operand */
+    case 283: /* case_else */
+    case 286: /* vinto */
+    case 293: /* when_clause */
+    case 298: /* key_opt */
+    case 315: /* filter_clause */
+{
+sqlite3ExprDelete(pParse->db, (yypminor->yy590));
+}
+      break;
+    case 223: /* eidlist_opt */
+    case 233: /* sortlist */
+    case 234: /* eidlist */
+    case 246: /* selcollist */
+    case 249: /* groupby_opt */
+    case 251: /* orderby_opt */
+    case 255: /* nexprlist */
+    case 257: /* sclp */
+    case 264: /* exprlist */
+    case 271: /* setlist */
+    case 280: /* paren_exprlist */
+    case 282: /* case_exprlist */
+    case 314: /* part_opt */
+{
+sqlite3ExprListDelete(pParse->db, (yypminor->yy402));
+}
+      break;
+    case 240: /* fullname */
+    case 247: /* from */
+    case 259: /* seltablist */
+    case 260: /* stl_prefix */
+    case 265: /* xfullname */
+{
+sqlite3SrcListDelete(pParse->db, (yypminor->yy563));
+}
+      break;
+    case 243: /* wqlist */
+{
+sqlite3WithDelete(pParse->db, (yypminor->yy125));
+}
+      break;
+    case 253: /* window_clause */
+    case 310: /* windowdefn_list */
+{
+sqlite3WindowListDelete(pParse->db, (yypminor->yy483));
+}
+      break;
+    case 266: /* idlist */
+    case 273: /* idlist_opt */
+{
+sqlite3IdListDelete(pParse->db, (yypminor->yy204));
+}
+      break;
+    case 276: /* filter_over */
+    case 311: /* windowdefn */
+    case 312: /* window */
+    case 313: /* frame_opt */
+    case 316: /* over_clause */
+{
+sqlite3WindowDelete(pParse->db, (yypminor->yy483));
+}
+      break;
+    case 289: /* trigger_cmd_list */
+    case 294: /* trigger_cmd */
+{
+sqlite3DeleteTriggerStep(pParse->db, (yypminor->yy319));
+}
+      break;
+    case 291: /* trigger_event */
+{
+sqlite3IdListDelete(pParse->db, (yypminor->yy28).b);
+}
+      break;
+    case 318: /* frame_bound */
+    case 319: /* frame_bound_s */
+    case 320: /* frame_bound_e */
+{
+sqlite3ExprDelete(pParse->db, (yypminor->yy205).pExpr);
+}
+      break;
+/********* End destructor definitions *****************************************/
+    default:  break;   /* If no destructor action specified: do nothing */
+  }
+}
+
+/*
+** Pop the parser's stack once.
+**
+** If there is a destructor routine associated with the token which
+** is popped from the stack, then call it.
+*/
+static void yy_pop_parser_stack(yyParser *pParser){
+  yyStackEntry *yytos;
+  assert( pParser->yytos!=0 );
+  assert( pParser->yytos > pParser->yystack );
+  yytos = pParser->yytos--;
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sPopping %s\n",
+      yyTracePrompt,
+      yyTokenName[yytos->major]);
+  }
+#endif
+  yy_destructor(pParser, yytos->major, &yytos->minor);
+}
+
+/*
+** Clear all secondary memory allocations from the parser
+*/
+SQLITE_PRIVATE void sqlite3ParserFinalize(void *p){
+  yyParser *pParser = (yyParser*)p;
+
+  /* In-lined version of calling yy_pop_parser_stack() for each
+  ** element left in the stack */
+  yyStackEntry *yytos = pParser->yytos;
+  while( yytos>pParser->yystack ){
+#ifndef NDEBUG
+    if( yyTraceFILE ){
+      fprintf(yyTraceFILE,"%sPopping %s\n",
+        yyTracePrompt,
+        yyTokenName[yytos->major]);
+    }
+#endif
+    if( yytos->major>=YY_MIN_DSTRCTR ){
+      yy_destructor(pParser, yytos->major, &yytos->minor);
+    }
+    yytos--;
+  }
+
+#if YYGROWABLESTACK
+  if( pParser->yystack!=pParser->yystk0 ) YYFREE(pParser->yystack);
+#endif
+}
+
+#ifndef sqlite3Parser_ENGINEALWAYSONSTACK
+/*
+** Deallocate and destroy a parser.  Destructors are called for
+** all stack elements before shutting the parser down.
+**
+** If the YYPARSEFREENEVERNULL macro exists (for example because it
+** is defined in a %include section of the input grammar) then it is
+** assumed that the input pointer is never NULL.
+*/
+SQLITE_PRIVATE void sqlite3ParserFree(
+  void *p,                    /* The parser to be deleted */
+  void (*freeProc)(void*)     /* Function used to reclaim memory */
+){
+#ifndef YYPARSEFREENEVERNULL
+  if( p==0 ) return;
+#endif
+  sqlite3ParserFinalize(p);
+  (*freeProc)(p);
+}
+#endif /* sqlite3Parser_ENGINEALWAYSONSTACK */
+
+/*
+** Return the peak depth of the stack for a parser.
+*/
+#ifdef YYTRACKMAXSTACKDEPTH
+SQLITE_PRIVATE int sqlite3ParserStackPeak(void *p){
+  yyParser *pParser = (yyParser*)p;
+  return pParser->yyhwm;
+}
+#endif
+
+/* This array of booleans keeps track of the parser statement
+** coverage.  The element yycoverage[X][Y] is set when the parser
+** is in state X and has a lookahead token Y.  In a well-tested
+** systems, every element of this matrix should end up being set.
+*/
+#if defined(YYCOVERAGE)
+static unsigned char yycoverage[YYNSTATE][YYNTOKEN];
+#endif
+
+/*
+** Write into out a description of every state/lookahead combination that
+**
+**   (1)  has not been used by the parser, and
+**   (2)  is not a syntax error.
+**
+** Return the number of missed state/lookahead combinations.
+*/
+#if defined(YYCOVERAGE)
+SQLITE_PRIVATE int sqlite3ParserCoverage(FILE *out){
+  int stateno, iLookAhead, i;
+  int nMissed = 0;
+  for(stateno=0; stateno<YYNSTATE; stateno++){
+    i = yy_shift_ofst[stateno];
+    for(iLookAhead=0; iLookAhead<YYNTOKEN; iLookAhead++){
+      if( yy_lookahead[i+iLookAhead]!=iLookAhead ) continue;
+      if( yycoverage[stateno][iLookAhead]==0 ) nMissed++;
+      if( out ){
+        fprintf(out,"State %d lookahead %s %s\n", stateno,
+                yyTokenName[iLookAhead],
+                yycoverage[stateno][iLookAhead] ? "ok" : "missed");
+      }
+    }
+  }
+  return nMissed;
+}
+#endif
+
+/*
+** Find the appropriate action for a parser given the terminal
+** look-ahead token iLookAhead.
+*/
+static YYACTIONTYPE yy_find_shift_action(
+  YYCODETYPE iLookAhead,    /* The look-ahead token */
+  YYACTIONTYPE stateno      /* Current state number */
+){
+  int i;
+
+  if( stateno>YY_MAX_SHIFT ) return stateno;
+  assert( stateno <= YY_SHIFT_COUNT );
+#if defined(YYCOVERAGE)
+  yycoverage[stateno][iLookAhead] = 1;
+#endif
+  do{
+    i = yy_shift_ofst[stateno];
+    assert( i>=0 );
+    assert( i<=YY_ACTTAB_COUNT );
+    assert( i+YYNTOKEN<=(int)YY_NLOOKAHEAD );
+    assert( iLookAhead!=YYNOCODE );
+    assert( iLookAhead < YYNTOKEN );
+    i += iLookAhead;
+    assert( i<(int)YY_NLOOKAHEAD );
+    if( yy_lookahead[i]!=iLookAhead ){
+#ifdef YYFALLBACK
+      YYCODETYPE iFallback;            /* Fallback token */
+      assert( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0]) );
+      iFallback = yyFallback[iLookAhead];
+      if( iFallback!=0 ){
+#ifndef NDEBUG
+        if( yyTraceFILE ){
+          fprintf(yyTraceFILE, "%sFALLBACK %s => %s\n",
+             yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[iFallback]);
+        }
+#endif
+        assert( yyFallback[iFallback]==0 ); /* Fallback loop must terminate */
+        iLookAhead = iFallback;
+        continue;
+      }
+#endif
+#ifdef YYWILDCARD
+      {
+        int j = i - iLookAhead + YYWILDCARD;
+        assert( j<(int)(sizeof(yy_lookahead)/sizeof(yy_lookahead[0])) );
+        if( yy_lookahead[j]==YYWILDCARD && iLookAhead>0 ){
+#ifndef NDEBUG
+          if( yyTraceFILE ){
+            fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
+               yyTracePrompt, yyTokenName[iLookAhead],
+               yyTokenName[YYWILDCARD]);
+          }
+#endif /* NDEBUG */
+          return yy_action[j];
+        }
+      }
+#endif /* YYWILDCARD */
+      return yy_default[stateno];
+    }else{
+      assert( i>=0 && i<(int)(sizeof(yy_action)/sizeof(yy_action[0])) );
+      return yy_action[i];
+    }
+  }while(1);
+}
+
+/*
+** Find the appropriate action for a parser given the non-terminal
+** look-ahead token iLookAhead.
+*/
+static YYACTIONTYPE yy_find_reduce_action(
+  YYACTIONTYPE stateno,     /* Current state number */
+  YYCODETYPE iLookAhead     /* The look-ahead token */
+){
+  int i;
+#ifdef YYERRORSYMBOL
+  if( stateno>YY_REDUCE_COUNT ){
+    return yy_default[stateno];
+  }
+#else
+  assert( stateno<=YY_REDUCE_COUNT );
+#endif
+  i = yy_reduce_ofst[stateno];
+  assert( iLookAhead!=YYNOCODE );
+  i += iLookAhead;
+#ifdef YYERRORSYMBOL
+  if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
+    return yy_default[stateno];
+  }
+#else
+  assert( i>=0 && i<YY_ACTTAB_COUNT );
+  assert( yy_lookahead[i]==iLookAhead );
+#endif
+  return yy_action[i];
+}
+
+/*
+** The following routine is called if the stack overflows.
+*/
+static void yyStackOverflow(yyParser *yypParser){
+   sqlite3ParserARG_FETCH
+   sqlite3ParserCTX_FETCH
+#ifndef NDEBUG
+   if( yyTraceFILE ){
+     fprintf(yyTraceFILE,"%sStack Overflow!\n",yyTracePrompt);
+   }
+#endif
+   while( yypParser->yytos>yypParser->yystack ) yy_pop_parser_stack(yypParser);
+   /* Here code is inserted which will execute if the parser
+   ** stack every overflows */
+/******** Begin %stack_overflow code ******************************************/
+
+  sqlite3OomFault(pParse->db);
+/******** End %stack_overflow code ********************************************/
+   sqlite3ParserARG_STORE /* Suppress warning about unused %extra_argument var */
+   sqlite3ParserCTX_STORE
+}
+
+/*
+** Print tracing information for a SHIFT action
+*/
+#ifndef NDEBUG
+static void yyTraceShift(yyParser *yypParser, int yyNewState, const char *zTag){
+  if( yyTraceFILE ){
+    if( yyNewState<YYNSTATE ){
+      fprintf(yyTraceFILE,"%s%s '%s', go to state %d\n",
+         yyTracePrompt, zTag, yyTokenName[yypParser->yytos->major],
+         yyNewState);
+    }else{
+      fprintf(yyTraceFILE,"%s%s '%s', pending reduce %d\n",
+         yyTracePrompt, zTag, yyTokenName[yypParser->yytos->major],
+         yyNewState - YY_MIN_REDUCE);
+    }
+  }
+}
+#else
+# define yyTraceShift(X,Y,Z)
+#endif
+
+/*
+** Perform a shift action.
+*/
+static void yy_shift(
+  yyParser *yypParser,          /* The parser to be shifted */
+  YYACTIONTYPE yyNewState,      /* The new state to shift in */
+  YYCODETYPE yyMajor,           /* The major token to shift in */
+  sqlite3ParserTOKENTYPE yyMinor        /* The minor token to shift in */
+){
+  yyStackEntry *yytos;
+  yypParser->yytos++;
+#ifdef YYTRACKMAXSTACKDEPTH
+  if( (int)(yypParser->yytos - yypParser->yystack)>yypParser->yyhwm ){
+    yypParser->yyhwm++;
+    assert( yypParser->yyhwm == (int)(yypParser->yytos - yypParser->yystack) );
+  }
+#endif
+  yytos = yypParser->yytos;
+  if( yytos>yypParser->yystackEnd ){
+    if( yyGrowStack(yypParser) ){
+      yypParser->yytos--;
+      yyStackOverflow(yypParser);
+      return;
+    }
+    yytos = yypParser->yytos;
+    assert( yytos <= yypParser->yystackEnd );
+  }
+  if( yyNewState > YY_MAX_SHIFT ){
+    yyNewState += YY_MIN_REDUCE - YY_MIN_SHIFTREDUCE;
+  }
+  yytos->stateno = yyNewState;
+  yytos->major = yyMajor;
+  yytos->minor.yy0 = yyMinor;
+  yyTraceShift(yypParser, yyNewState, "Shift");
+}
+
+/* For rule J, yyRuleInfoLhs[J] contains the symbol on the left-hand side
+** of that rule */
+static const YYCODETYPE yyRuleInfoLhs[] = {
+   191,  /* (0) explain ::= EXPLAIN */
+   191,  /* (1) explain ::= EXPLAIN QUERY PLAN */
+   190,  /* (2) cmdx ::= cmd */
+   192,  /* (3) cmd ::= BEGIN transtype trans_opt */
+   193,  /* (4) transtype ::= */
+   193,  /* (5) transtype ::= DEFERRED */
+   193,  /* (6) transtype ::= IMMEDIATE */
+   193,  /* (7) transtype ::= EXCLUSIVE */
+   192,  /* (8) cmd ::= COMMIT|END trans_opt */
+   192,  /* (9) cmd ::= ROLLBACK trans_opt */
+   192,  /* (10) cmd ::= SAVEPOINT nm */
+   192,  /* (11) cmd ::= RELEASE savepoint_opt nm */
+   192,  /* (12) cmd ::= ROLLBACK trans_opt TO savepoint_opt nm */
+   197,  /* (13) create_table ::= createkw temp TABLE ifnotexists nm dbnm */
+   199,  /* (14) createkw ::= CREATE */
+   201,  /* (15) ifnotexists ::= */
+   201,  /* (16) ifnotexists ::= IF NOT EXISTS */
+   200,  /* (17) temp ::= TEMP */
+   200,  /* (18) temp ::= */
+   198,  /* (19) create_table_args ::= LP columnlist conslist_opt RP table_option_set */
+   198,  /* (20) create_table_args ::= AS select */
+   205,  /* (21) table_option_set ::= */
+   205,  /* (22) table_option_set ::= table_option_set COMMA table_option */
+   207,  /* (23) table_option ::= WITHOUT nm */
+   207,  /* (24) table_option ::= nm */
+   208,  /* (25) columnname ::= nm typetoken */
+   210,  /* (26) typetoken ::= */
+   210,  /* (27) typetoken ::= typename LP signed RP */
+   210,  /* (28) typetoken ::= typename LP signed COMMA signed RP */
+   211,  /* (29) typename ::= typename ID|STRING */
+   215,  /* (30) scanpt ::= */
+   216,  /* (31) scantok ::= */
+   217,  /* (32) ccons ::= CONSTRAINT nm */
+   217,  /* (33) ccons ::= DEFAULT scantok term */
+   217,  /* (34) ccons ::= DEFAULT LP expr RP */
+   217,  /* (35) ccons ::= DEFAULT PLUS scantok term */
+   217,  /* (36) ccons ::= DEFAULT MINUS scantok term */
+   217,  /* (37) ccons ::= DEFAULT scantok ID|INDEXED */
+   217,  /* (38) ccons ::= NOT NULL onconf */
+   217,  /* (39) ccons ::= PRIMARY KEY sortorder onconf autoinc */
+   217,  /* (40) ccons ::= UNIQUE onconf */
+   217,  /* (41) ccons ::= CHECK LP expr RP */
+   217,  /* (42) ccons ::= REFERENCES nm eidlist_opt refargs */
+   217,  /* (43) ccons ::= defer_subclause */
+   217,  /* (44) ccons ::= COLLATE ID|STRING */
+   226,  /* (45) generated ::= LP expr RP */
+   226,  /* (46) generated ::= LP expr RP ID */
+   222,  /* (47) autoinc ::= */
+   222,  /* (48) autoinc ::= AUTOINCR */
+   224,  /* (49) refargs ::= */
+   224,  /* (50) refargs ::= refargs refarg */
+   227,  /* (51) refarg ::= MATCH nm */
+   227,  /* (52) refarg ::= ON INSERT refact */
+   227,  /* (53) refarg ::= ON DELETE refact */
+   227,  /* (54) refarg ::= ON UPDATE refact */
+   228,  /* (55) refact ::= SET NULL */
+   228,  /* (56) refact ::= SET DEFAULT */
+   228,  /* (57) refact ::= CASCADE */
+   228,  /* (58) refact ::= RESTRICT */
+   228,  /* (59) refact ::= NO ACTION */
+   225,  /* (60) defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt */
+   225,  /* (61) defer_subclause ::= DEFERRABLE init_deferred_pred_opt */
+   229,  /* (62) init_deferred_pred_opt ::= */
+   229,  /* (63) init_deferred_pred_opt ::= INITIALLY DEFERRED */
+   229,  /* (64) init_deferred_pred_opt ::= INITIALLY IMMEDIATE */
+   204,  /* (65) conslist_opt ::= */
+   231,  /* (66) tconscomma ::= COMMA */
+   232,  /* (67) tcons ::= CONSTRAINT nm */
+   232,  /* (68) tcons ::= PRIMARY KEY LP sortlist autoinc RP onconf */
+   232,  /* (69) tcons ::= UNIQUE LP sortlist RP onconf */
+   232,  /* (70) tcons ::= CHECK LP expr RP onconf */
+   232,  /* (71) tcons ::= FOREIGN KEY LP eidlist RP REFERENCES nm eidlist_opt refargs defer_subclause_opt */
+   235,  /* (72) defer_subclause_opt ::= */
+   220,  /* (73) onconf ::= */
+   220,  /* (74) onconf ::= ON CONFLICT resolvetype */
+   236,  /* (75) orconf ::= */
+   236,  /* (76) orconf ::= OR resolvetype */
+   237,  /* (77) resolvetype ::= IGNORE */
+   237,  /* (78) resolvetype ::= REPLACE */
+   192,  /* (79) cmd ::= DROP TABLE ifexists fullname */
+   239,  /* (80) ifexists ::= IF EXISTS */
+   239,  /* (81) ifexists ::= */
+   192,  /* (82) cmd ::= createkw temp VIEW ifnotexists nm dbnm eidlist_opt AS select */
+   192,  /* (83) cmd ::= DROP VIEW ifexists fullname */
+   192,  /* (84) cmd ::= select */
+   206,  /* (85) select ::= WITH wqlist selectnowith */
+   206,  /* (86) select ::= WITH RECURSIVE wqlist selectnowith */
+   206,  /* (87) select ::= selectnowith */
+   241,  /* (88) selectnowith ::= selectnowith multiselect_op oneselect */
+   244,  /* (89) multiselect_op ::= UNION */
+   244,  /* (90) multiselect_op ::= UNION ALL */
+   244,  /* (91) multiselect_op ::= EXCEPT|INTERSECT */
+   242,  /* (92) oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt */
+   242,  /* (93) oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt window_clause orderby_opt limit_opt */
+   254,  /* (94) values ::= VALUES LP nexprlist RP */
+   242,  /* (95) oneselect ::= mvalues */
+   256,  /* (96) mvalues ::= values COMMA LP nexprlist RP */
+   256,  /* (97) mvalues ::= mvalues COMMA LP nexprlist RP */
+   245,  /* (98) distinct ::= DISTINCT */
+   245,  /* (99) distinct ::= ALL */
+   245,  /* (100) distinct ::= */
+   257,  /* (101) sclp ::= */
+   246,  /* (102) selcollist ::= sclp scanpt expr scanpt as */
+   246,  /* (103) selcollist ::= sclp scanpt STAR */
+   246,  /* (104) selcollist ::= sclp scanpt nm DOT STAR */
+   258,  /* (105) as ::= AS nm */
+   258,  /* (106) as ::= */
+   247,  /* (107) from ::= */
+   247,  /* (108) from ::= FROM seltablist */
+   260,  /* (109) stl_prefix ::= seltablist joinop */
+   260,  /* (110) stl_prefix ::= */
+   259,  /* (111) seltablist ::= stl_prefix nm dbnm as on_using */
+   259,  /* (112) seltablist ::= stl_prefix nm dbnm as indexed_by on_using */
+   259,  /* (113) seltablist ::= stl_prefix nm dbnm LP exprlist RP as on_using */
+   259,  /* (114) seltablist ::= stl_prefix LP select RP as on_using */
+   259,  /* (115) seltablist ::= stl_prefix LP seltablist RP as on_using */
+   202,  /* (116) dbnm ::= */
+   202,  /* (117) dbnm ::= DOT nm */
+   240,  /* (118) fullname ::= nm */
+   240,  /* (119) fullname ::= nm DOT nm */
+   265,  /* (120) xfullname ::= nm */
+   265,  /* (121) xfullname ::= nm DOT nm */
+   265,  /* (122) xfullname ::= nm DOT nm AS nm */
+   265,  /* (123) xfullname ::= nm AS nm */
+   261,  /* (124) joinop ::= COMMA|JOIN */
+   261,  /* (125) joinop ::= JOIN_KW JOIN */
+   261,  /* (126) joinop ::= JOIN_KW nm JOIN */
+   261,  /* (127) joinop ::= JOIN_KW nm nm JOIN */
+   262,  /* (128) on_using ::= ON expr */
+   262,  /* (129) on_using ::= USING LP idlist RP */
+   262,  /* (130) on_using ::= */
+   267,  /* (131) indexed_opt ::= */
+   263,  /* (132) indexed_by ::= INDEXED BY nm */
+   263,  /* (133) indexed_by ::= NOT INDEXED */
+   251,  /* (134) orderby_opt ::= */
+   251,  /* (135) orderby_opt ::= ORDER BY sortlist */
+   233,  /* (136) sortlist ::= sortlist COMMA expr sortorder nulls */
+   233,  /* (137) sortlist ::= expr sortorder nulls */
+   221,  /* (138) sortorder ::= ASC */
+   221,  /* (139) sortorder ::= DESC */
+   221,  /* (140) sortorder ::= */
+   268,  /* (141) nulls ::= NULLS FIRST */
+   268,  /* (142) nulls ::= NULLS LAST */
+   268,  /* (143) nulls ::= */
+   249,  /* (144) groupby_opt ::= */
+   249,  /* (145) groupby_opt ::= GROUP BY nexprlist */
+   250,  /* (146) having_opt ::= */
+   250,  /* (147) having_opt ::= HAVING expr */
+   252,  /* (148) limit_opt ::= */
+   252,  /* (149) limit_opt ::= LIMIT expr */
+   252,  /* (150) limit_opt ::= LIMIT expr OFFSET expr */
+   252,  /* (151) limit_opt ::= LIMIT expr COMMA expr */
+   192,  /* (152) cmd ::= with DELETE FROM xfullname indexed_opt where_opt_ret orderby_opt limit_opt */
+   248,  /* (153) where_opt ::= */
+   248,  /* (154) where_opt ::= WHERE expr */
+   270,  /* (155) where_opt_ret ::= */
+   270,  /* (156) where_opt_ret ::= WHERE expr */
+   270,  /* (157) where_opt_ret ::= RETURNING selcollist */
+   270,  /* (158) where_opt_ret ::= WHERE expr RETURNING selcollist */
+   192,  /* (159) cmd ::= with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret orderby_opt limit_opt */
+   271,  /* (160) setlist ::= setlist COMMA nm EQ expr */
+   271,  /* (161) setlist ::= setlist COMMA LP idlist RP EQ expr */
+   271,  /* (162) setlist ::= nm EQ expr */
+   271,  /* (163) setlist ::= LP idlist RP EQ expr */
+   192,  /* (164) cmd ::= with insert_cmd INTO xfullname idlist_opt select upsert */
+   192,  /* (165) cmd ::= with insert_cmd INTO xfullname idlist_opt DEFAULT VALUES returning */
+   274,  /* (166) upsert ::= */
+   274,  /* (167) upsert ::= RETURNING selcollist */
+   274,  /* (168) upsert ::= ON CONFLICT LP sortlist RP where_opt DO UPDATE SET setlist where_opt upsert */
+   274,  /* (169) upsert ::= ON CONFLICT LP sortlist RP where_opt DO NOTHING upsert */
+   274,  /* (170) upsert ::= ON CONFLICT DO NOTHING returning */
+   274,  /* (171) upsert ::= ON CONFLICT DO UPDATE SET setlist where_opt returning */
+   275,  /* (172) returning ::= RETURNING selcollist */
+   272,  /* (173) insert_cmd ::= INSERT orconf */
+   272,  /* (174) insert_cmd ::= REPLACE */
+   273,  /* (175) idlist_opt ::= */
+   273,  /* (176) idlist_opt ::= LP idlist RP */
+   266,  /* (177) idlist ::= idlist COMMA nm */
+   266,  /* (178) idlist ::= nm */
+   219,  /* (179) expr ::= LP expr RP */
+   219,  /* (180) expr ::= ID|INDEXED|JOIN_KW */
+   219,  /* (181) expr ::= nm DOT nm */
+   219,  /* (182) expr ::= nm DOT nm DOT nm */
+   218,  /* (183) term ::= NULL|FLOAT|BLOB */
+   218,  /* (184) term ::= STRING */
+   218,  /* (185) term ::= INTEGER */
+   219,  /* (186) expr ::= VARIABLE */
+   219,  /* (187) expr ::= expr COLLATE ID|STRING */
+   219,  /* (188) expr ::= CAST LP expr AS typetoken RP */
+   219,  /* (189) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP */
+   219,  /* (190) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP */
+   219,  /* (191) expr ::= ID|INDEXED|JOIN_KW LP STAR RP */
+   219,  /* (192) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP filter_over */
+   219,  /* (193) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP filter_over */
+   219,  /* (194) expr ::= ID|INDEXED|JOIN_KW LP STAR RP filter_over */
+   218,  /* (195) term ::= CTIME_KW */
+   219,  /* (196) expr ::= LP nexprlist COMMA expr RP */
+   219,  /* (197) expr ::= expr AND expr */
+   219,  /* (198) expr ::= expr OR expr */
+   219,  /* (199) expr ::= expr LT|GT|GE|LE expr */
+   219,  /* (200) expr ::= expr EQ|NE expr */
+   219,  /* (201) expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr */
+   219,  /* (202) expr ::= expr PLUS|MINUS expr */
+   219,  /* (203) expr ::= expr STAR|SLASH|REM expr */
+   219,  /* (204) expr ::= expr CONCAT expr */
+   277,  /* (205) likeop ::= NOT LIKE_KW|MATCH */
+   219,  /* (206) expr ::= expr likeop expr */
+   219,  /* (207) expr ::= expr likeop expr ESCAPE expr */
+   219,  /* (208) expr ::= expr ISNULL|NOTNULL */
+   219,  /* (209) expr ::= expr NOT NULL */
+   219,  /* (210) expr ::= expr IS expr */
+   219,  /* (211) expr ::= expr IS NOT expr */
+   219,  /* (212) expr ::= expr IS NOT DISTINCT FROM expr */
+   219,  /* (213) expr ::= expr IS DISTINCT FROM expr */
+   219,  /* (214) expr ::= NOT expr */
+   219,  /* (215) expr ::= BITNOT expr */
+   219,  /* (216) expr ::= PLUS|MINUS expr */
+   219,  /* (217) expr ::= expr PTR expr */
+   278,  /* (218) between_op ::= BETWEEN */
+   278,  /* (219) between_op ::= NOT BETWEEN */
+   219,  /* (220) expr ::= expr between_op expr AND expr */
+   279,  /* (221) in_op ::= IN */
+   279,  /* (222) in_op ::= NOT IN */
+   219,  /* (223) expr ::= expr in_op LP exprlist RP */
+   219,  /* (224) expr ::= LP select RP */
+   219,  /* (225) expr ::= expr in_op LP select RP */
+   219,  /* (226) expr ::= expr in_op nm dbnm paren_exprlist */
+   219,  /* (227) expr ::= EXISTS LP select RP */
+   219,  /* (228) expr ::= CASE case_operand case_exprlist case_else END */
+   282,  /* (229) case_exprlist ::= case_exprlist WHEN expr THEN expr */
+   282,  /* (230) case_exprlist ::= WHEN expr THEN expr */
+   283,  /* (231) case_else ::= ELSE expr */
+   283,  /* (232) case_else ::= */
+   281,  /* (233) case_operand ::= */
+   264,  /* (234) exprlist ::= */
+   255,  /* (235) nexprlist ::= nexprlist COMMA expr */
+   255,  /* (236) nexprlist ::= expr */
+   280,  /* (237) paren_exprlist ::= */
+   280,  /* (238) paren_exprlist ::= LP exprlist RP */
+   192,  /* (239) cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP sortlist RP where_opt */
+   284,  /* (240) uniqueflag ::= UNIQUE */
+   284,  /* (241) uniqueflag ::= */
+   223,  /* (242) eidlist_opt ::= */
+   223,  /* (243) eidlist_opt ::= LP eidlist RP */
+   234,  /* (244) eidlist ::= eidlist COMMA nm collate sortorder */
+   234,  /* (245) eidlist ::= nm collate sortorder */
+   285,  /* (246) collate ::= */
+   285,  /* (247) collate ::= COLLATE ID|STRING */
+   192,  /* (248) cmd ::= DROP INDEX ifexists fullname */
+   192,  /* (249) cmd ::= VACUUM vinto */
+   192,  /* (250) cmd ::= VACUUM nm vinto */
+   286,  /* (251) vinto ::= INTO expr */
+   286,  /* (252) vinto ::= */
+   192,  /* (253) cmd ::= PRAGMA nm dbnm */
+   192,  /* (254) cmd ::= PRAGMA nm dbnm EQ nmnum */
+   192,  /* (255) cmd ::= PRAGMA nm dbnm LP nmnum RP */
+   192,  /* (256) cmd ::= PRAGMA nm dbnm EQ minus_num */
+   192,  /* (257) cmd ::= PRAGMA nm dbnm LP minus_num RP */
+   213,  /* (258) plus_num ::= PLUS INTEGER|FLOAT */
+   214,  /* (259) minus_num ::= MINUS INTEGER|FLOAT */
+   192,  /* (260) cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END */
+   288,  /* (261) trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause */
+   290,  /* (262) trigger_time ::= BEFORE|AFTER */
+   290,  /* (263) trigger_time ::= INSTEAD OF */
+   290,  /* (264) trigger_time ::= */
+   291,  /* (265) trigger_event ::= DELETE|INSERT */
+   291,  /* (266) trigger_event ::= UPDATE */
+   291,  /* (267) trigger_event ::= UPDATE OF idlist */
+   293,  /* (268) when_clause ::= */
+   293,  /* (269) when_clause ::= WHEN expr */
+   289,  /* (270) trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI */
+   289,  /* (271) trigger_cmd_list ::= trigger_cmd SEMI */
+   295,  /* (272) trnm ::= nm DOT nm */
+   296,  /* (273) tridxby ::= INDEXED BY nm */
+   296,  /* (274) tridxby ::= NOT INDEXED */
+   294,  /* (275) trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist from where_opt scanpt */
+   294,  /* (276) trigger_cmd ::= scanpt insert_cmd INTO trnm idlist_opt select upsert scanpt */
+   294,  /* (277) trigger_cmd ::= DELETE FROM trnm tridxby where_opt scanpt */
+   294,  /* (278) trigger_cmd ::= scanpt select scanpt */
+   219,  /* (279) expr ::= RAISE LP IGNORE RP */
+   219,  /* (280) expr ::= RAISE LP raisetype COMMA expr RP */
+   238,  /* (281) raisetype ::= ROLLBACK */
+   238,  /* (282) raisetype ::= ABORT */
+   238,  /* (283) raisetype ::= FAIL */
+   192,  /* (284) cmd ::= DROP TRIGGER ifexists fullname */
+   192,  /* (285) cmd ::= ATTACH database_kw_opt expr AS expr key_opt */
+   192,  /* (286) cmd ::= DETACH database_kw_opt expr */
+   298,  /* (287) key_opt ::= */
+   298,  /* (288) key_opt ::= KEY expr */
+   192,  /* (289) cmd ::= REINDEX */
+   192,  /* (290) cmd ::= REINDEX nm dbnm */
+   192,  /* (291) cmd ::= ANALYZE */
+   192,  /* (292) cmd ::= ANALYZE nm dbnm */
+   192,  /* (293) cmd ::= ALTER TABLE fullname RENAME TO nm */
+   192,  /* (294) cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt columnname carglist */
+   192,  /* (295) cmd ::= ALTER TABLE fullname DROP kwcolumn_opt nm */
+   299,  /* (296) add_column_fullname ::= fullname */
+   192,  /* (297) cmd ::= ALTER TABLE fullname RENAME kwcolumn_opt nm TO nm */
+   192,  /* (298) cmd ::= create_vtab */
+   192,  /* (299) cmd ::= create_vtab LP vtabarglist RP */
+   301,  /* (300) create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm */
+   303,  /* (301) vtabarg ::= */
+   304,  /* (302) vtabargtoken ::= ANY */
+   304,  /* (303) vtabargtoken ::= lp anylist RP */
+   305,  /* (304) lp ::= LP */
+   269,  /* (305) with ::= WITH wqlist */
+   269,  /* (306) with ::= WITH RECURSIVE wqlist */
+   308,  /* (307) wqas ::= AS */
+   308,  /* (308) wqas ::= AS MATERIALIZED */
+   308,  /* (309) wqas ::= AS NOT MATERIALIZED */
+   307,  /* (310) wqitem ::= withnm eidlist_opt wqas LP select RP */
+   309,  /* (311) withnm ::= nm */
+   243,  /* (312) wqlist ::= wqitem */
+   243,  /* (313) wqlist ::= wqlist COMMA wqitem */
+   310,  /* (314) windowdefn_list ::= windowdefn_list COMMA windowdefn */
+   311,  /* (315) windowdefn ::= nm AS LP window RP */
+   312,  /* (316) window ::= PARTITION BY nexprlist orderby_opt frame_opt */
+   312,  /* (317) window ::= nm PARTITION BY nexprlist orderby_opt frame_opt */
+   312,  /* (318) window ::= ORDER BY sortlist frame_opt */
+   312,  /* (319) window ::= nm ORDER BY sortlist frame_opt */
+   312,  /* (320) window ::= nm frame_opt */
+   313,  /* (321) frame_opt ::= */
+   313,  /* (322) frame_opt ::= range_or_rows frame_bound_s frame_exclude_opt */
+   313,  /* (323) frame_opt ::= range_or_rows BETWEEN frame_bound_s AND frame_bound_e frame_exclude_opt */
+   317,  /* (324) range_or_rows ::= RANGE|ROWS|GROUPS */
+   319,  /* (325) frame_bound_s ::= frame_bound */
+   319,  /* (326) frame_bound_s ::= UNBOUNDED PRECEDING */
+   320,  /* (327) frame_bound_e ::= frame_bound */
+   320,  /* (328) frame_bound_e ::= UNBOUNDED FOLLOWING */
+   318,  /* (329) frame_bound ::= expr PRECEDING|FOLLOWING */
+   318,  /* (330) frame_bound ::= CURRENT ROW */
+   321,  /* (331) frame_exclude_opt ::= */
+   321,  /* (332) frame_exclude_opt ::= EXCLUDE frame_exclude */
+   322,  /* (333) frame_exclude ::= NO OTHERS */
+   322,  /* (334) frame_exclude ::= CURRENT ROW */
+   322,  /* (335) frame_exclude ::= GROUP|TIES */
+   253,  /* (336) window_clause ::= WINDOW windowdefn_list */
+   276,  /* (337) filter_over ::= filter_clause over_clause */
+   276,  /* (338) filter_over ::= over_clause */
+   276,  /* (339) filter_over ::= filter_clause */
+   316,  /* (340) over_clause ::= OVER LP window RP */
+   316,  /* (341) over_clause ::= OVER nm */
+   315,  /* (342) filter_clause ::= FILTER LP WHERE expr RP */
+   218,  /* (343) term ::= QNUMBER */
+   187,  /* (344) input ::= cmdlist */
+   188,  /* (345) cmdlist ::= cmdlist ecmd */
+   188,  /* (346) cmdlist ::= ecmd */
+   189,  /* (347) ecmd ::= SEMI */
+   189,  /* (348) ecmd ::= cmdx SEMI */
+   189,  /* (349) ecmd ::= explain cmdx SEMI */
+   194,  /* (350) trans_opt ::= */
+   194,  /* (351) trans_opt ::= TRANSACTION */
+   194,  /* (352) trans_opt ::= TRANSACTION nm */
+   196,  /* (353) savepoint_opt ::= SAVEPOINT */
+   196,  /* (354) savepoint_opt ::= */
+   192,  /* (355) cmd ::= create_table create_table_args */
+   205,  /* (356) table_option_set ::= table_option */
+   203,  /* (357) columnlist ::= columnlist COMMA columnname carglist */
+   203,  /* (358) columnlist ::= columnname carglist */
+   195,  /* (359) nm ::= ID|INDEXED|JOIN_KW */
+   195,  /* (360) nm ::= STRING */
+   210,  /* (361) typetoken ::= typename */
+   211,  /* (362) typename ::= ID|STRING */
+   212,  /* (363) signed ::= plus_num */
+   212,  /* (364) signed ::= minus_num */
+   209,  /* (365) carglist ::= carglist ccons */
+   209,  /* (366) carglist ::= */
+   217,  /* (367) ccons ::= NULL onconf */
+   217,  /* (368) ccons ::= GENERATED ALWAYS AS generated */
+   217,  /* (369) ccons ::= AS generated */
+   204,  /* (370) conslist_opt ::= COMMA conslist */
+   230,  /* (371) conslist ::= conslist tconscomma tcons */
+   230,  /* (372) conslist ::= tcons */
+   231,  /* (373) tconscomma ::= */
+   235,  /* (374) defer_subclause_opt ::= defer_subclause */
+   237,  /* (375) resolvetype ::= raisetype */
+   241,  /* (376) selectnowith ::= oneselect */
+   242,  /* (377) oneselect ::= values */
+   257,  /* (378) sclp ::= selcollist COMMA */
+   258,  /* (379) as ::= ID|STRING */
+   267,  /* (380) indexed_opt ::= indexed_by */
+   275,  /* (381) returning ::= */
+   219,  /* (382) expr ::= term */
+   277,  /* (383) likeop ::= LIKE_KW|MATCH */
+   281,  /* (384) case_operand ::= expr */
+   264,  /* (385) exprlist ::= nexprlist */
+   287,  /* (386) nmnum ::= plus_num */
+   287,  /* (387) nmnum ::= nm */
+   287,  /* (388) nmnum ::= ON */
+   287,  /* (389) nmnum ::= DELETE */
+   287,  /* (390) nmnum ::= DEFAULT */
+   213,  /* (391) plus_num ::= INTEGER|FLOAT */
+   292,  /* (392) foreach_clause ::= */
+   292,  /* (393) foreach_clause ::= FOR EACH ROW */
+   295,  /* (394) trnm ::= nm */
+   296,  /* (395) tridxby ::= */
+   297,  /* (396) database_kw_opt ::= DATABASE */
+   297,  /* (397) database_kw_opt ::= */
+   300,  /* (398) kwcolumn_opt ::= */
+   300,  /* (399) kwcolumn_opt ::= COLUMNKW */
+   302,  /* (400) vtabarglist ::= vtabarg */
+   302,  /* (401) vtabarglist ::= vtabarglist COMMA vtabarg */
+   303,  /* (402) vtabarg ::= vtabarg vtabargtoken */
+   306,  /* (403) anylist ::= */
+   306,  /* (404) anylist ::= anylist LP anylist RP */
+   306,  /* (405) anylist ::= anylist ANY */
+   269,  /* (406) with ::= */
+   310,  /* (407) windowdefn_list ::= windowdefn */
+   312,  /* (408) window ::= frame_opt */
+};
+
+/* For rule J, yyRuleInfoNRhs[J] contains the negative of the number
+** of symbols on the right-hand side of that rule. */
+static const signed char yyRuleInfoNRhs[] = {
+   -1,  /* (0) explain ::= EXPLAIN */
+   -3,  /* (1) explain ::= EXPLAIN QUERY PLAN */
+   -1,  /* (2) cmdx ::= cmd */
+   -3,  /* (3) cmd ::= BEGIN transtype trans_opt */
+    0,  /* (4) transtype ::= */
+   -1,  /* (5) transtype ::= DEFERRED */
+   -1,  /* (6) transtype ::= IMMEDIATE */
+   -1,  /* (7) transtype ::= EXCLUSIVE */
+   -2,  /* (8) cmd ::= COMMIT|END trans_opt */
+   -2,  /* (9) cmd ::= ROLLBACK trans_opt */
+   -2,  /* (10) cmd ::= SAVEPOINT nm */
+   -3,  /* (11) cmd ::= RELEASE savepoint_opt nm */
+   -5,  /* (12) cmd ::= ROLLBACK trans_opt TO savepoint_opt nm */
+   -6,  /* (13) create_table ::= createkw temp TABLE ifnotexists nm dbnm */
+   -1,  /* (14) createkw ::= CREATE */
+    0,  /* (15) ifnotexists ::= */
+   -3,  /* (16) ifnotexists ::= IF NOT EXISTS */
+   -1,  /* (17) temp ::= TEMP */
+    0,  /* (18) temp ::= */
+   -5,  /* (19) create_table_args ::= LP columnlist conslist_opt RP table_option_set */
+   -2,  /* (20) create_table_args ::= AS select */
+    0,  /* (21) table_option_set ::= */
+   -3,  /* (22) table_option_set ::= table_option_set COMMA table_option */
+   -2,  /* (23) table_option ::= WITHOUT nm */
+   -1,  /* (24) table_option ::= nm */
+   -2,  /* (25) columnname ::= nm typetoken */
+    0,  /* (26) typetoken ::= */
+   -4,  /* (27) typetoken ::= typename LP signed RP */
+   -6,  /* (28) typetoken ::= typename LP signed COMMA signed RP */
+   -2,  /* (29) typename ::= typename ID|STRING */
+    0,  /* (30) scanpt ::= */
+    0,  /* (31) scantok ::= */
+   -2,  /* (32) ccons ::= CONSTRAINT nm */
+   -3,  /* (33) ccons ::= DEFAULT scantok term */
+   -4,  /* (34) ccons ::= DEFAULT LP expr RP */
+   -4,  /* (35) ccons ::= DEFAULT PLUS scantok term */
+   -4,  /* (36) ccons ::= DEFAULT MINUS scantok term */
+   -3,  /* (37) ccons ::= DEFAULT scantok ID|INDEXED */
+   -3,  /* (38) ccons ::= NOT NULL onconf */
+   -5,  /* (39) ccons ::= PRIMARY KEY sortorder onconf autoinc */
+   -2,  /* (40) ccons ::= UNIQUE onconf */
+   -4,  /* (41) ccons ::= CHECK LP expr RP */
+   -4,  /* (42) ccons ::= REFERENCES nm eidlist_opt refargs */
+   -1,  /* (43) ccons ::= defer_subclause */
+   -2,  /* (44) ccons ::= COLLATE ID|STRING */
+   -3,  /* (45) generated ::= LP expr RP */
+   -4,  /* (46) generated ::= LP expr RP ID */
+    0,  /* (47) autoinc ::= */
+   -1,  /* (48) autoinc ::= AUTOINCR */
+    0,  /* (49) refargs ::= */
+   -2,  /* (50) refargs ::= refargs refarg */
+   -2,  /* (51) refarg ::= MATCH nm */
+   -3,  /* (52) refarg ::= ON INSERT refact */
+   -3,  /* (53) refarg ::= ON DELETE refact */
+   -3,  /* (54) refarg ::= ON UPDATE refact */
+   -2,  /* (55) refact ::= SET NULL */
+   -2,  /* (56) refact ::= SET DEFAULT */
+   -1,  /* (57) refact ::= CASCADE */
+   -1,  /* (58) refact ::= RESTRICT */
+   -2,  /* (59) refact ::= NO ACTION */
+   -3,  /* (60) defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt */
+   -2,  /* (61) defer_subclause ::= DEFERRABLE init_deferred_pred_opt */
+    0,  /* (62) init_deferred_pred_opt ::= */
+   -2,  /* (63) init_deferred_pred_opt ::= INITIALLY DEFERRED */
+   -2,  /* (64) init_deferred_pred_opt ::= INITIALLY IMMEDIATE */
+    0,  /* (65) conslist_opt ::= */
+   -1,  /* (66) tconscomma ::= COMMA */
+   -2,  /* (67) tcons ::= CONSTRAINT nm */
+   -7,  /* (68) tcons ::= PRIMARY KEY LP sortlist autoinc RP onconf */
+   -5,  /* (69) tcons ::= UNIQUE LP sortlist RP onconf */
+   -5,  /* (70) tcons ::= CHECK LP expr RP onconf */
+  -10,  /* (71) tcons ::= FOREIGN KEY LP eidlist RP REFERENCES nm eidlist_opt refargs defer_subclause_opt */
+    0,  /* (72) defer_subclause_opt ::= */
+    0,  /* (73) onconf ::= */
+   -3,  /* (74) onconf ::= ON CONFLICT resolvetype */
+    0,  /* (75) orconf ::= */
+   -2,  /* (76) orconf ::= OR resolvetype */
+   -1,  /* (77) resolvetype ::= IGNORE */
+   -1,  /* (78) resolvetype ::= REPLACE */
+   -4,  /* (79) cmd ::= DROP TABLE ifexists fullname */
+   -2,  /* (80) ifexists ::= IF EXISTS */
+    0,  /* (81) ifexists ::= */
+   -9,  /* (82) cmd ::= createkw temp VIEW ifnotexists nm dbnm eidlist_opt AS select */
+   -4,  /* (83) cmd ::= DROP VIEW ifexists fullname */
+   -1,  /* (84) cmd ::= select */
+   -3,  /* (85) select ::= WITH wqlist selectnowith */
+   -4,  /* (86) select ::= WITH RECURSIVE wqlist selectnowith */
+   -1,  /* (87) select ::= selectnowith */
+   -3,  /* (88) selectnowith ::= selectnowith multiselect_op oneselect */
+   -1,  /* (89) multiselect_op ::= UNION */
+   -2,  /* (90) multiselect_op ::= UNION ALL */
+   -1,  /* (91) multiselect_op ::= EXCEPT|INTERSECT */
+   -9,  /* (92) oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt */
+  -10,  /* (93) oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt window_clause orderby_opt limit_opt */
+   -4,  /* (94) values ::= VALUES LP nexprlist RP */
+   -1,  /* (95) oneselect ::= mvalues */
+   -5,  /* (96) mvalues ::= values COMMA LP nexprlist RP */
+   -5,  /* (97) mvalues ::= mvalues COMMA LP nexprlist RP */
+   -1,  /* (98) distinct ::= DISTINCT */
+   -1,  /* (99) distinct ::= ALL */
+    0,  /* (100) distinct ::= */
+    0,  /* (101) sclp ::= */
+   -5,  /* (102) selcollist ::= sclp scanpt expr scanpt as */
+   -3,  /* (103) selcollist ::= sclp scanpt STAR */
+   -5,  /* (104) selcollist ::= sclp scanpt nm DOT STAR */
+   -2,  /* (105) as ::= AS nm */
+    0,  /* (106) as ::= */
+    0,  /* (107) from ::= */
+   -2,  /* (108) from ::= FROM seltablist */
+   -2,  /* (109) stl_prefix ::= seltablist joinop */
+    0,  /* (110) stl_prefix ::= */
+   -5,  /* (111) seltablist ::= stl_prefix nm dbnm as on_using */
+   -6,  /* (112) seltablist ::= stl_prefix nm dbnm as indexed_by on_using */
+   -8,  /* (113) seltablist ::= stl_prefix nm dbnm LP exprlist RP as on_using */
+   -6,  /* (114) seltablist ::= stl_prefix LP select RP as on_using */
+   -6,  /* (115) seltablist ::= stl_prefix LP seltablist RP as on_using */
+    0,  /* (116) dbnm ::= */
+   -2,  /* (117) dbnm ::= DOT nm */
+   -1,  /* (118) fullname ::= nm */
+   -3,  /* (119) fullname ::= nm DOT nm */
+   -1,  /* (120) xfullname ::= nm */
+   -3,  /* (121) xfullname ::= nm DOT nm */
+   -5,  /* (122) xfullname ::= nm DOT nm AS nm */
+   -3,  /* (123) xfullname ::= nm AS nm */
+   -1,  /* (124) joinop ::= COMMA|JOIN */
+   -2,  /* (125) joinop ::= JOIN_KW JOIN */
+   -3,  /* (126) joinop ::= JOIN_KW nm JOIN */
+   -4,  /* (127) joinop ::= JOIN_KW nm nm JOIN */
+   -2,  /* (128) on_using ::= ON expr */
+   -4,  /* (129) on_using ::= USING LP idlist RP */
+    0,  /* (130) on_using ::= */
+    0,  /* (131) indexed_opt ::= */
+   -3,  /* (132) indexed_by ::= INDEXED BY nm */
+   -2,  /* (133) indexed_by ::= NOT INDEXED */
+    0,  /* (134) orderby_opt ::= */
+   -3,  /* (135) orderby_opt ::= ORDER BY sortlist */
+   -5,  /* (136) sortlist ::= sortlist COMMA expr sortorder nulls */
+   -3,  /* (137) sortlist ::= expr sortorder nulls */
+   -1,  /* (138) sortorder ::= ASC */
+   -1,  /* (139) sortorder ::= DESC */
+    0,  /* (140) sortorder ::= */
+   -2,  /* (141) nulls ::= NULLS FIRST */
+   -2,  /* (142) nulls ::= NULLS LAST */
+    0,  /* (143) nulls ::= */
+    0,  /* (144) groupby_opt ::= */
+   -3,  /* (145) groupby_opt ::= GROUP BY nexprlist */
+    0,  /* (146) having_opt ::= */
+   -2,  /* (147) having_opt ::= HAVING expr */
+    0,  /* (148) limit_opt ::= */
+   -2,  /* (149) limit_opt ::= LIMIT expr */
+   -4,  /* (150) limit_opt ::= LIMIT expr OFFSET expr */
+   -4,  /* (151) limit_opt ::= LIMIT expr COMMA expr */
+   -8,  /* (152) cmd ::= with DELETE FROM xfullname indexed_opt where_opt_ret orderby_opt limit_opt */
+    0,  /* (153) where_opt ::= */
+   -2,  /* (154) where_opt ::= WHERE expr */
+    0,  /* (155) where_opt_ret ::= */
+   -2,  /* (156) where_opt_ret ::= WHERE expr */
+   -2,  /* (157) where_opt_ret ::= RETURNING selcollist */
+   -4,  /* (158) where_opt_ret ::= WHERE expr RETURNING selcollist */
+  -11,  /* (159) cmd ::= with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret orderby_opt limit_opt */
+   -5,  /* (160) setlist ::= setlist COMMA nm EQ expr */
+   -7,  /* (161) setlist ::= setlist COMMA LP idlist RP EQ expr */
+   -3,  /* (162) setlist ::= nm EQ expr */
+   -5,  /* (163) setlist ::= LP idlist RP EQ expr */
+   -7,  /* (164) cmd ::= with insert_cmd INTO xfullname idlist_opt select upsert */
+   -8,  /* (165) cmd ::= with insert_cmd INTO xfullname idlist_opt DEFAULT VALUES returning */
+    0,  /* (166) upsert ::= */
+   -2,  /* (167) upsert ::= RETURNING selcollist */
+  -12,  /* (168) upsert ::= ON CONFLICT LP sortlist RP where_opt DO UPDATE SET setlist where_opt upsert */
+   -9,  /* (169) upsert ::= ON CONFLICT LP sortlist RP where_opt DO NOTHING upsert */
+   -5,  /* (170) upsert ::= ON CONFLICT DO NOTHING returning */
+   -8,  /* (171) upsert ::= ON CONFLICT DO UPDATE SET setlist where_opt returning */
+   -2,  /* (172) returning ::= RETURNING selcollist */
+   -2,  /* (173) insert_cmd ::= INSERT orconf */
+   -1,  /* (174) insert_cmd ::= REPLACE */
+    0,  /* (175) idlist_opt ::= */
+   -3,  /* (176) idlist_opt ::= LP idlist RP */
+   -3,  /* (177) idlist ::= idlist COMMA nm */
+   -1,  /* (178) idlist ::= nm */
+   -3,  /* (179) expr ::= LP expr RP */
+   -1,  /* (180) expr ::= ID|INDEXED|JOIN_KW */
+   -3,  /* (181) expr ::= nm DOT nm */
+   -5,  /* (182) expr ::= nm DOT nm DOT nm */
+   -1,  /* (183) term ::= NULL|FLOAT|BLOB */
+   -1,  /* (184) term ::= STRING */
+   -1,  /* (185) term ::= INTEGER */
+   -1,  /* (186) expr ::= VARIABLE */
+   -3,  /* (187) expr ::= expr COLLATE ID|STRING */
+   -6,  /* (188) expr ::= CAST LP expr AS typetoken RP */
+   -5,  /* (189) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP */
+   -8,  /* (190) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP */
+   -4,  /* (191) expr ::= ID|INDEXED|JOIN_KW LP STAR RP */
+   -6,  /* (192) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP filter_over */
+   -9,  /* (193) expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP filter_over */
+   -5,  /* (194) expr ::= ID|INDEXED|JOIN_KW LP STAR RP filter_over */
+   -1,  /* (195) term ::= CTIME_KW */
+   -5,  /* (196) expr ::= LP nexprlist COMMA expr RP */
+   -3,  /* (197) expr ::= expr AND expr */
+   -3,  /* (198) expr ::= expr OR expr */
+   -3,  /* (199) expr ::= expr LT|GT|GE|LE expr */
+   -3,  /* (200) expr ::= expr EQ|NE expr */
+   -3,  /* (201) expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr */
+   -3,  /* (202) expr ::= expr PLUS|MINUS expr */
+   -3,  /* (203) expr ::= expr STAR|SLASH|REM expr */
+   -3,  /* (204) expr ::= expr CONCAT expr */
+   -2,  /* (205) likeop ::= NOT LIKE_KW|MATCH */
+   -3,  /* (206) expr ::= expr likeop expr */
+   -5,  /* (207) expr ::= expr likeop expr ESCAPE expr */
+   -2,  /* (208) expr ::= expr ISNULL|NOTNULL */
+   -3,  /* (209) expr ::= expr NOT NULL */
+   -3,  /* (210) expr ::= expr IS expr */
+   -4,  /* (211) expr ::= expr IS NOT expr */
+   -6,  /* (212) expr ::= expr IS NOT DISTINCT FROM expr */
+   -5,  /* (213) expr ::= expr IS DISTINCT FROM expr */
+   -2,  /* (214) expr ::= NOT expr */
+   -2,  /* (215) expr ::= BITNOT expr */
+   -2,  /* (216) expr ::= PLUS|MINUS expr */
+   -3,  /* (217) expr ::= expr PTR expr */
+   -1,  /* (218) between_op ::= BETWEEN */
+   -2,  /* (219) between_op ::= NOT BETWEEN */
+   -5,  /* (220) expr ::= expr between_op expr AND expr */
+   -1,  /* (221) in_op ::= IN */
+   -2,  /* (222) in_op ::= NOT IN */
+   -5,  /* (223) expr ::= expr in_op LP exprlist RP */
+   -3,  /* (224) expr ::= LP select RP */
+   -5,  /* (225) expr ::= expr in_op LP select RP */
+   -5,  /* (226) expr ::= expr in_op nm dbnm paren_exprlist */
+   -4,  /* (227) expr ::= EXISTS LP select RP */
+   -5,  /* (228) expr ::= CASE case_operand case_exprlist case_else END */
+   -5,  /* (229) case_exprlist ::= case_exprlist WHEN expr THEN expr */
+   -4,  /* (230) case_exprlist ::= WHEN expr THEN expr */
+   -2,  /* (231) case_else ::= ELSE expr */
+    0,  /* (232) case_else ::= */
+    0,  /* (233) case_operand ::= */
+    0,  /* (234) exprlist ::= */
+   -3,  /* (235) nexprlist ::= nexprlist COMMA expr */
+   -1,  /* (236) nexprlist ::= expr */
+    0,  /* (237) paren_exprlist ::= */
+   -3,  /* (238) paren_exprlist ::= LP exprlist RP */
+  -12,  /* (239) cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP sortlist RP where_opt */
+   -1,  /* (240) uniqueflag ::= UNIQUE */
+    0,  /* (241) uniqueflag ::= */
+    0,  /* (242) eidlist_opt ::= */
+   -3,  /* (243) eidlist_opt ::= LP eidlist RP */
+   -5,  /* (244) eidlist ::= eidlist COMMA nm collate sortorder */
+   -3,  /* (245) eidlist ::= nm collate sortorder */
+    0,  /* (246) collate ::= */
+   -2,  /* (247) collate ::= COLLATE ID|STRING */
+   -4,  /* (248) cmd ::= DROP INDEX ifexists fullname */
+   -2,  /* (249) cmd ::= VACUUM vinto */
+   -3,  /* (250) cmd ::= VACUUM nm vinto */
+   -2,  /* (251) vinto ::= INTO expr */
+    0,  /* (252) vinto ::= */
+   -3,  /* (253) cmd ::= PRAGMA nm dbnm */
+   -5,  /* (254) cmd ::= PRAGMA nm dbnm EQ nmnum */
+   -6,  /* (255) cmd ::= PRAGMA nm dbnm LP nmnum RP */
+   -5,  /* (256) cmd ::= PRAGMA nm dbnm EQ minus_num */
+   -6,  /* (257) cmd ::= PRAGMA nm dbnm LP minus_num RP */
+   -2,  /* (258) plus_num ::= PLUS INTEGER|FLOAT */
+   -2,  /* (259) minus_num ::= MINUS INTEGER|FLOAT */
+   -5,  /* (260) cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END */
+  -11,  /* (261) trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause */
+   -1,  /* (262) trigger_time ::= BEFORE|AFTER */
+   -2,  /* (263) trigger_time ::= INSTEAD OF */
+    0,  /* (264) trigger_time ::= */
+   -1,  /* (265) trigger_event ::= DELETE|INSERT */
+   -1,  /* (266) trigger_event ::= UPDATE */
+   -3,  /* (267) trigger_event ::= UPDATE OF idlist */
+    0,  /* (268) when_clause ::= */
+   -2,  /* (269) when_clause ::= WHEN expr */
+   -3,  /* (270) trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI */
+   -2,  /* (271) trigger_cmd_list ::= trigger_cmd SEMI */
+   -3,  /* (272) trnm ::= nm DOT nm */
+   -3,  /* (273) tridxby ::= INDEXED BY nm */
+   -2,  /* (274) tridxby ::= NOT INDEXED */
+   -9,  /* (275) trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist from where_opt scanpt */
+   -8,  /* (276) trigger_cmd ::= scanpt insert_cmd INTO trnm idlist_opt select upsert scanpt */
+   -6,  /* (277) trigger_cmd ::= DELETE FROM trnm tridxby where_opt scanpt */
+   -3,  /* (278) trigger_cmd ::= scanpt select scanpt */
+   -4,  /* (279) expr ::= RAISE LP IGNORE RP */
+   -6,  /* (280) expr ::= RAISE LP raisetype COMMA expr RP */
+   -1,  /* (281) raisetype ::= ROLLBACK */
+   -1,  /* (282) raisetype ::= ABORT */
+   -1,  /* (283) raisetype ::= FAIL */
+   -4,  /* (284) cmd ::= DROP TRIGGER ifexists fullname */
+   -6,  /* (285) cmd ::= ATTACH database_kw_opt expr AS expr key_opt */
+   -3,  /* (286) cmd ::= DETACH database_kw_opt expr */
+    0,  /* (287) key_opt ::= */
+   -2,  /* (288) key_opt ::= KEY expr */
+   -1,  /* (289) cmd ::= REINDEX */
+   -3,  /* (290) cmd ::= REINDEX nm dbnm */
+   -1,  /* (291) cmd ::= ANALYZE */
+   -3,  /* (292) cmd ::= ANALYZE nm dbnm */
+   -6,  /* (293) cmd ::= ALTER TABLE fullname RENAME TO nm */
+   -7,  /* (294) cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt columnname carglist */
+   -6,  /* (295) cmd ::= ALTER TABLE fullname DROP kwcolumn_opt nm */
+   -1,  /* (296) add_column_fullname ::= fullname */
+   -8,  /* (297) cmd ::= ALTER TABLE fullname RENAME kwcolumn_opt nm TO nm */
+   -1,  /* (298) cmd ::= create_vtab */
+   -4,  /* (299) cmd ::= create_vtab LP vtabarglist RP */
+   -8,  /* (300) create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm */
+    0,  /* (301) vtabarg ::= */
+   -1,  /* (302) vtabargtoken ::= ANY */
+   -3,  /* (303) vtabargtoken ::= lp anylist RP */
+   -1,  /* (304) lp ::= LP */
+   -2,  /* (305) with ::= WITH wqlist */
+   -3,  /* (306) with ::= WITH RECURSIVE wqlist */
+   -1,  /* (307) wqas ::= AS */
+   -2,  /* (308) wqas ::= AS MATERIALIZED */
+   -3,  /* (309) wqas ::= AS NOT MATERIALIZED */
+   -6,  /* (310) wqitem ::= withnm eidlist_opt wqas LP select RP */
+   -1,  /* (311) withnm ::= nm */
+   -1,  /* (312) wqlist ::= wqitem */
+   -3,  /* (313) wqlist ::= wqlist COMMA wqitem */
+   -3,  /* (314) windowdefn_list ::= windowdefn_list COMMA windowdefn */
+   -5,  /* (315) windowdefn ::= nm AS LP window RP */
+   -5,  /* (316) window ::= PARTITION BY nexprlist orderby_opt frame_opt */
+   -6,  /* (317) window ::= nm PARTITION BY nexprlist orderby_opt frame_opt */
+   -4,  /* (318) window ::= ORDER BY sortlist frame_opt */
+   -5,  /* (319) window ::= nm ORDER BY sortlist frame_opt */
+   -2,  /* (320) window ::= nm frame_opt */
+    0,  /* (321) frame_opt ::= */
+   -3,  /* (322) frame_opt ::= range_or_rows frame_bound_s frame_exclude_opt */
+   -6,  /* (323) frame_opt ::= range_or_rows BETWEEN frame_bound_s AND frame_bound_e frame_exclude_opt */
+   -1,  /* (324) range_or_rows ::= RANGE|ROWS|GROUPS */
+   -1,  /* (325) frame_bound_s ::= frame_bound */
+   -2,  /* (326) frame_bound_s ::= UNBOUNDED PRECEDING */
+   -1,  /* (327) frame_bound_e ::= frame_bound */
+   -2,  /* (328) frame_bound_e ::= UNBOUNDED FOLLOWING */
+   -2,  /* (329) frame_bound ::= expr PRECEDING|FOLLOWING */
+   -2,  /* (330) frame_bound ::= CURRENT ROW */
+    0,  /* (331) frame_exclude_opt ::= */
+   -2,  /* (332) frame_exclude_opt ::= EXCLUDE frame_exclude */
+   -2,  /* (333) frame_exclude ::= NO OTHERS */
+   -2,  /* (334) frame_exclude ::= CURRENT ROW */
+   -1,  /* (335) frame_exclude ::= GROUP|TIES */
+   -2,  /* (336) window_clause ::= WINDOW windowdefn_list */
+   -2,  /* (337) filter_over ::= filter_clause over_clause */
+   -1,  /* (338) filter_over ::= over_clause */
+   -1,  /* (339) filter_over ::= filter_clause */
+   -4,  /* (340) over_clause ::= OVER LP window RP */
+   -2,  /* (341) over_clause ::= OVER nm */
+   -5,  /* (342) filter_clause ::= FILTER LP WHERE expr RP */
+   -1,  /* (343) term ::= QNUMBER */
+   -1,  /* (344) input ::= cmdlist */
+   -2,  /* (345) cmdlist ::= cmdlist ecmd */
+   -1,  /* (346) cmdlist ::= ecmd */
+   -1,  /* (347) ecmd ::= SEMI */
+   -2,  /* (348) ecmd ::= cmdx SEMI */
+   -3,  /* (349) ecmd ::= explain cmdx SEMI */
+    0,  /* (350) trans_opt ::= */
+   -1,  /* (351) trans_opt ::= TRANSACTION */
+   -2,  /* (352) trans_opt ::= TRANSACTION nm */
+   -1,  /* (353) savepoint_opt ::= SAVEPOINT */
+    0,  /* (354) savepoint_opt ::= */
+   -2,  /* (355) cmd ::= create_table create_table_args */
+   -1,  /* (356) table_option_set ::= table_option */
+   -4,  /* (357) columnlist ::= columnlist COMMA columnname carglist */
+   -2,  /* (358) columnlist ::= columnname carglist */
+   -1,  /* (359) nm ::= ID|INDEXED|JOIN_KW */
+   -1,  /* (360) nm ::= STRING */
+   -1,  /* (361) typetoken ::= typename */
+   -1,  /* (362) typename ::= ID|STRING */
+   -1,  /* (363) signed ::= plus_num */
+   -1,  /* (364) signed ::= minus_num */
+   -2,  /* (365) carglist ::= carglist ccons */
+    0,  /* (366) carglist ::= */
+   -2,  /* (367) ccons ::= NULL onconf */
+   -4,  /* (368) ccons ::= GENERATED ALWAYS AS generated */
+   -2,  /* (369) ccons ::= AS generated */
+   -2,  /* (370) conslist_opt ::= COMMA conslist */
+   -3,  /* (371) conslist ::= conslist tconscomma tcons */
+   -1,  /* (372) conslist ::= tcons */
+    0,  /* (373) tconscomma ::= */
+   -1,  /* (374) defer_subclause_opt ::= defer_subclause */
+   -1,  /* (375) resolvetype ::= raisetype */
+   -1,  /* (376) selectnowith ::= oneselect */
+   -1,  /* (377) oneselect ::= values */
+   -2,  /* (378) sclp ::= selcollist COMMA */
+   -1,  /* (379) as ::= ID|STRING */
+   -1,  /* (380) indexed_opt ::= indexed_by */
+    0,  /* (381) returning ::= */
+   -1,  /* (382) expr ::= term */
+   -1,  /* (383) likeop ::= LIKE_KW|MATCH */
+   -1,  /* (384) case_operand ::= expr */
+   -1,  /* (385) exprlist ::= nexprlist */
+   -1,  /* (386) nmnum ::= plus_num */
+   -1,  /* (387) nmnum ::= nm */
+   -1,  /* (388) nmnum ::= ON */
+   -1,  /* (389) nmnum ::= DELETE */
+   -1,  /* (390) nmnum ::= DEFAULT */
+   -1,  /* (391) plus_num ::= INTEGER|FLOAT */
+    0,  /* (392) foreach_clause ::= */
+   -3,  /* (393) foreach_clause ::= FOR EACH ROW */
+   -1,  /* (394) trnm ::= nm */
+    0,  /* (395) tridxby ::= */
+   -1,  /* (396) database_kw_opt ::= DATABASE */
+    0,  /* (397) database_kw_opt ::= */
+    0,  /* (398) kwcolumn_opt ::= */
+   -1,  /* (399) kwcolumn_opt ::= COLUMNKW */
+   -1,  /* (400) vtabarglist ::= vtabarg */
+   -3,  /* (401) vtabarglist ::= vtabarglist COMMA vtabarg */
+   -2,  /* (402) vtabarg ::= vtabarg vtabargtoken */
+    0,  /* (403) anylist ::= */
+   -4,  /* (404) anylist ::= anylist LP anylist RP */
+   -2,  /* (405) anylist ::= anylist ANY */
+    0,  /* (406) with ::= */
+   -1,  /* (407) windowdefn_list ::= windowdefn */
+   -1,  /* (408) window ::= frame_opt */
+};
+
+static void yy_accept(yyParser*);  /* Forward Declaration */
+
+/*
+** Perform a reduce action and the shift that must immediately
+** follow the reduce.
+**
+** The yyLookahead and yyLookaheadToken parameters provide reduce actions
+** access to the lookahead token (if any).  The yyLookahead will be YYNOCODE
+** if the lookahead token has already been consumed.  As this procedure is
+** only called from one place, optimizing compilers will in-line it, which
+** means that the extra parameters have no performance impact.
+*/
+static YYACTIONTYPE yy_reduce(
+  yyParser *yypParser,         /* The parser */
+  unsigned int yyruleno,       /* Number of the rule by which to reduce */
+  int yyLookahead,             /* Lookahead token, or YYNOCODE if none */
+  sqlite3ParserTOKENTYPE yyLookaheadToken  /* Value of the lookahead token */
+  sqlite3ParserCTX_PDECL                   /* %extra_context */
+){
+  int yygoto;                     /* The next state */
+  YYACTIONTYPE yyact;             /* The next action */
+  yyStackEntry *yymsp;            /* The top of the parser's stack */
+  int yysize;                     /* Amount to pop the stack */
+  sqlite3ParserARG_FETCH
+  (void)yyLookahead;
+  (void)yyLookaheadToken;
+  yymsp = yypParser->yytos;
+
+  switch( yyruleno ){
+  /* Beginning here are the reduction cases.  A typical example
+  ** follows:
+  **   case 0:
+  **  #line <lineno> <grammarfile>
+  **     { ... }           // User supplied code
+  **  #line <lineno> <thisfile>
+  **     break;
+  */
+/********** Begin reduce actions **********************************************/
+        YYMINORTYPE yylhsminor;
+      case 0: /* explain ::= EXPLAIN */
+{ if( pParse->pReprepare==0 ) pParse->explain = 1; }
+        break;
+      case 1: /* explain ::= EXPLAIN QUERY PLAN */
+{ if( pParse->pReprepare==0 ) pParse->explain = 2; }
+        break;
+      case 2: /* cmdx ::= cmd */
+{ sqlite3FinishCoding(pParse); }
+        break;
+      case 3: /* cmd ::= BEGIN transtype trans_opt */
+{sqlite3BeginTransaction(pParse, yymsp[-1].minor.yy502);}
+        break;
+      case 4: /* transtype ::= */
+{yymsp[1].minor.yy502 = TK_DEFERRED;}
+        break;
+      case 5: /* transtype ::= DEFERRED */
+      case 6: /* transtype ::= IMMEDIATE */ yytestcase(yyruleno==6);
+      case 7: /* transtype ::= EXCLUSIVE */ yytestcase(yyruleno==7);
+      case 324: /* range_or_rows ::= RANGE|ROWS|GROUPS */ yytestcase(yyruleno==324);
+{yymsp[0].minor.yy502 = yymsp[0].major; /*A-overwrites-X*/}
+        break;
+      case 8: /* cmd ::= COMMIT|END trans_opt */
+      case 9: /* cmd ::= ROLLBACK trans_opt */ yytestcase(yyruleno==9);
+{sqlite3EndTransaction(pParse,yymsp[-1].major);}
+        break;
+      case 10: /* cmd ::= SAVEPOINT nm */
+{
+  sqlite3Savepoint(pParse, SAVEPOINT_BEGIN, &yymsp[0].minor.yy0);
+}
+        break;
+      case 11: /* cmd ::= RELEASE savepoint_opt nm */
+{
+  sqlite3Savepoint(pParse, SAVEPOINT_RELEASE, &yymsp[0].minor.yy0);
+}
+        break;
+      case 12: /* cmd ::= ROLLBACK trans_opt TO savepoint_opt nm */
+{
+  sqlite3Savepoint(pParse, SAVEPOINT_ROLLBACK, &yymsp[0].minor.yy0);
+}
+        break;
+      case 13: /* create_table ::= createkw temp TABLE ifnotexists nm dbnm */
+{
+   sqlite3StartTable(pParse,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy0,yymsp[-4].minor.yy502,0,0,yymsp[-2].minor.yy502);
+}
+        break;
+      case 14: /* createkw ::= CREATE */
+{disableLookaside(pParse);}
+        break;
+      case 15: /* ifnotexists ::= */
+      case 18: /* temp ::= */ yytestcase(yyruleno==18);
+      case 47: /* autoinc ::= */ yytestcase(yyruleno==47);
+      case 62: /* init_deferred_pred_opt ::= */ yytestcase(yyruleno==62);
+      case 72: /* defer_subclause_opt ::= */ yytestcase(yyruleno==72);
+      case 81: /* ifexists ::= */ yytestcase(yyruleno==81);
+      case 100: /* distinct ::= */ yytestcase(yyruleno==100);
+      case 246: /* collate ::= */ yytestcase(yyruleno==246);
+{yymsp[1].minor.yy502 = 0;}
+        break;
+      case 16: /* ifnotexists ::= IF NOT EXISTS */
+{yymsp[-2].minor.yy502 = 1;}
+        break;
+      case 17: /* temp ::= TEMP */
+{yymsp[0].minor.yy502 = pParse->db->init.busy==0;}
+        break;
+      case 19: /* create_table_args ::= LP columnlist conslist_opt RP table_option_set */
+{
+  sqlite3EndTable(pParse,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0,yymsp[0].minor.yy9,0);
+}
+        break;
+      case 20: /* create_table_args ::= AS select */
+{
+  sqlite3EndTable(pParse,0,0,0,yymsp[0].minor.yy637);
+  sqlite3SelectDelete(pParse->db, yymsp[0].minor.yy637);
+}
+        break;
+      case 21: /* table_option_set ::= */
+{yymsp[1].minor.yy9 = 0;}
+        break;
+      case 22: /* table_option_set ::= table_option_set COMMA table_option */
+{yylhsminor.yy9 = yymsp[-2].minor.yy9|yymsp[0].minor.yy9;}
+  yymsp[-2].minor.yy9 = yylhsminor.yy9;
+        break;
+      case 23: /* table_option ::= WITHOUT nm */
+{
+  if( yymsp[0].minor.yy0.n==5 && sqlite3_strnicmp(yymsp[0].minor.yy0.z,"rowid",5)==0 ){
+    yymsp[-1].minor.yy9 = TF_WithoutRowid | TF_NoVisibleRowid;
+  }else{
+    yymsp[-1].minor.yy9 = 0;
+    sqlite3ErrorMsg(pParse, "unknown table option: %.*s", yymsp[0].minor.yy0.n, yymsp[0].minor.yy0.z);
+  }
+}
+        break;
+      case 24: /* table_option ::= nm */
+{
+  if( yymsp[0].minor.yy0.n==6 && sqlite3_strnicmp(yymsp[0].minor.yy0.z,"strict",6)==0 ){
+    yylhsminor.yy9 = TF_Strict;
+  }else{
+    yylhsminor.yy9 = 0;
+    sqlite3ErrorMsg(pParse, "unknown table option: %.*s", yymsp[0].minor.yy0.n, yymsp[0].minor.yy0.z);
+  }
+}
+  yymsp[0].minor.yy9 = yylhsminor.yy9;
+        break;
+      case 25: /* columnname ::= nm typetoken */
+{sqlite3AddColumn(pParse,yymsp[-1].minor.yy0,yymsp[0].minor.yy0);}
+        break;
+      case 26: /* typetoken ::= */
+      case 65: /* conslist_opt ::= */ yytestcase(yyruleno==65);
+      case 106: /* as ::= */ yytestcase(yyruleno==106);
+{yymsp[1].minor.yy0.n = 0; yymsp[1].minor.yy0.z = 0;}
+        break;
+      case 27: /* typetoken ::= typename LP signed RP */
+{
+  yymsp[-3].minor.yy0.n = (int)(&yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n] - yymsp[-3].minor.yy0.z);
+}
+        break;
+      case 28: /* typetoken ::= typename LP signed COMMA signed RP */
+{
+  yymsp[-5].minor.yy0.n = (int)(&yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n] - yymsp[-5].minor.yy0.z);
+}
+        break;
+      case 29: /* typename ::= typename ID|STRING */
+{yymsp[-1].minor.yy0.n=yymsp[0].minor.yy0.n+(int)(yymsp[0].minor.yy0.z-yymsp[-1].minor.yy0.z);}
+        break;
+      case 30: /* scanpt ::= */
+{
+  assert( yyLookahead!=YYNOCODE );
+  yymsp[1].minor.yy342 = yyLookaheadToken.z;
+}
+        break;
+      case 31: /* scantok ::= */
+{
+  assert( yyLookahead!=YYNOCODE );
+  yymsp[1].minor.yy0 = yyLookaheadToken;
+}
+        break;
+      case 32: /* ccons ::= CONSTRAINT nm */
+      case 67: /* tcons ::= CONSTRAINT nm */ yytestcase(yyruleno==67);
+{pParse->constraintName = yymsp[0].minor.yy0;}
+        break;
+      case 33: /* ccons ::= DEFAULT scantok term */
+{sqlite3AddDefaultValue(pParse,yymsp[0].minor.yy590,yymsp[-1].minor.yy0.z,&yymsp[-1].minor.yy0.z[yymsp[-1].minor.yy0.n]);}
+        break;
+      case 34: /* ccons ::= DEFAULT LP expr RP */
+{sqlite3AddDefaultValue(pParse,yymsp[-1].minor.yy590,yymsp[-2].minor.yy0.z+1,yymsp[0].minor.yy0.z);}
+        break;
+      case 35: /* ccons ::= DEFAULT PLUS scantok term */
+{sqlite3AddDefaultValue(pParse,yymsp[0].minor.yy590,yymsp[-2].minor.yy0.z,&yymsp[-1].minor.yy0.z[yymsp[-1].minor.yy0.n]);}
+        break;
+      case 36: /* ccons ::= DEFAULT MINUS scantok term */
+{
+  Expr *p = sqlite3PExpr(pParse, TK_UMINUS, yymsp[0].minor.yy590, 0);
+  sqlite3AddDefaultValue(pParse,p,yymsp[-2].minor.yy0.z,&yymsp[-1].minor.yy0.z[yymsp[-1].minor.yy0.n]);
+}
+        break;
+      case 37: /* ccons ::= DEFAULT scantok ID|INDEXED */
+{
+  Expr *p = tokenExpr(pParse, TK_STRING, yymsp[0].minor.yy0);
+  if( p ){
+    sqlite3ExprIdToTrueFalse(p);
+    testcase( p->op==TK_TRUEFALSE && sqlite3ExprTruthValue(p) );
+  }
+    sqlite3AddDefaultValue(pParse,p,yymsp[0].minor.yy0.z,yymsp[0].minor.yy0.z+yymsp[0].minor.yy0.n);
+}
+        break;
+      case 38: /* ccons ::= NOT NULL onconf */
+{sqlite3AddNotNull(pParse, yymsp[0].minor.yy502);}
+        break;
+      case 39: /* ccons ::= PRIMARY KEY sortorder onconf autoinc */
+{sqlite3AddPrimaryKey(pParse,0,yymsp[-1].minor.yy502,yymsp[0].minor.yy502,yymsp[-2].minor.yy502);}
+        break;
+      case 40: /* ccons ::= UNIQUE onconf */
+{sqlite3CreateIndex(pParse,0,0,0,0,yymsp[0].minor.yy502,0,0,0,0,
+                                   SQLITE_IDXTYPE_UNIQUE);}
+        break;
+      case 41: /* ccons ::= CHECK LP expr RP */
+{sqlite3AddCheckConstraint(pParse,yymsp[-1].minor.yy590,yymsp[-2].minor.yy0.z,yymsp[0].minor.yy0.z);}
+        break;
+      case 42: /* ccons ::= REFERENCES nm eidlist_opt refargs */
+{sqlite3CreateForeignKey(pParse,0,&yymsp[-2].minor.yy0,yymsp[-1].minor.yy402,yymsp[0].minor.yy502);}
+        break;
+      case 43: /* ccons ::= defer_subclause */
+{sqlite3DeferForeignKey(pParse,yymsp[0].minor.yy502);}
+        break;
+      case 44: /* ccons ::= COLLATE ID|STRING */
+{sqlite3AddCollateType(pParse, &yymsp[0].minor.yy0);}
+        break;
+      case 45: /* generated ::= LP expr RP */
+{sqlite3AddGenerated(pParse,yymsp[-1].minor.yy590,0);}
+        break;
+      case 46: /* generated ::= LP expr RP ID */
+{sqlite3AddGenerated(pParse,yymsp[-2].minor.yy590,&yymsp[0].minor.yy0);}
+        break;
+      case 48: /* autoinc ::= AUTOINCR */
+{yymsp[0].minor.yy502 = 1;}
+        break;
+      case 49: /* refargs ::= */
+{ yymsp[1].minor.yy502 = OE_None*0x0101; /* EV: R-19803-45884 */}
+        break;
+      case 50: /* refargs ::= refargs refarg */
+{ yymsp[-1].minor.yy502 = (yymsp[-1].minor.yy502 & ~yymsp[0].minor.yy481.mask) | yymsp[0].minor.yy481.value; }
+        break;
+      case 51: /* refarg ::= MATCH nm */
+{ yymsp[-1].minor.yy481.value = 0;     yymsp[-1].minor.yy481.mask = 0x000000; }
+        break;
+      case 52: /* refarg ::= ON INSERT refact */
+{ yymsp[-2].minor.yy481.value = 0;     yymsp[-2].minor.yy481.mask = 0x000000; }
+        break;
+      case 53: /* refarg ::= ON DELETE refact */
+{ yymsp[-2].minor.yy481.value = yymsp[0].minor.yy502;     yymsp[-2].minor.yy481.mask = 0x0000ff; }
+        break;
+      case 54: /* refarg ::= ON UPDATE refact */
+{ yymsp[-2].minor.yy481.value = yymsp[0].minor.yy502<<8;  yymsp[-2].minor.yy481.mask = 0x00ff00; }
+        break;
+      case 55: /* refact ::= SET NULL */
+{ yymsp[-1].minor.yy502 = OE_SetNull;  /* EV: R-33326-45252 */}
+        break;
+      case 56: /* refact ::= SET DEFAULT */
+{ yymsp[-1].minor.yy502 = OE_SetDflt;  /* EV: R-33326-45252 */}
+        break;
+      case 57: /* refact ::= CASCADE */
+{ yymsp[0].minor.yy502 = OE_Cascade;  /* EV: R-33326-45252 */}
+        break;
+      case 58: /* refact ::= RESTRICT */
+{ yymsp[0].minor.yy502 = OE_Restrict; /* EV: R-33326-45252 */}
+        break;
+      case 59: /* refact ::= NO ACTION */
+{ yymsp[-1].minor.yy502 = OE_None;     /* EV: R-33326-45252 */}
+        break;
+      case 60: /* defer_subclause ::= NOT DEFERRABLE init_deferred_pred_opt */
+{yymsp[-2].minor.yy502 = 0;}
+        break;
+      case 61: /* defer_subclause ::= DEFERRABLE init_deferred_pred_opt */
+      case 76: /* orconf ::= OR resolvetype */ yytestcase(yyruleno==76);
+      case 173: /* insert_cmd ::= INSERT orconf */ yytestcase(yyruleno==173);
+{yymsp[-1].minor.yy502 = yymsp[0].minor.yy502;}
+        break;
+      case 63: /* init_deferred_pred_opt ::= INITIALLY DEFERRED */
+      case 80: /* ifexists ::= IF EXISTS */ yytestcase(yyruleno==80);
+      case 219: /* between_op ::= NOT BETWEEN */ yytestcase(yyruleno==219);
+      case 222: /* in_op ::= NOT IN */ yytestcase(yyruleno==222);
+      case 247: /* collate ::= COLLATE ID|STRING */ yytestcase(yyruleno==247);
+{yymsp[-1].minor.yy502 = 1;}
+        break;
+      case 64: /* init_deferred_pred_opt ::= INITIALLY IMMEDIATE */
+{yymsp[-1].minor.yy502 = 0;}
+        break;
+      case 66: /* tconscomma ::= COMMA */
+{pParse->constraintName.n = 0;}
+        break;
+      case 68: /* tcons ::= PRIMARY KEY LP sortlist autoinc RP onconf */
+{sqlite3AddPrimaryKey(pParse,yymsp[-3].minor.yy402,yymsp[0].minor.yy502,yymsp[-2].minor.yy502,0);}
+        break;
+      case 69: /* tcons ::= UNIQUE LP sortlist RP onconf */
+{sqlite3CreateIndex(pParse,0,0,0,yymsp[-2].minor.yy402,yymsp[0].minor.yy502,0,0,0,0,
+                                       SQLITE_IDXTYPE_UNIQUE);}
+        break;
+      case 70: /* tcons ::= CHECK LP expr RP onconf */
+{sqlite3AddCheckConstraint(pParse,yymsp[-2].minor.yy590,yymsp[-3].minor.yy0.z,yymsp[-1].minor.yy0.z);}
+        break;
+      case 71: /* tcons ::= FOREIGN KEY LP eidlist RP REFERENCES nm eidlist_opt refargs defer_subclause_opt */
+{
+    sqlite3CreateForeignKey(pParse, yymsp[-6].minor.yy402, &yymsp[-3].minor.yy0, yymsp[-2].minor.yy402, yymsp[-1].minor.yy502);
+    sqlite3DeferForeignKey(pParse, yymsp[0].minor.yy502);
+}
+        break;
+      case 73: /* onconf ::= */
+      case 75: /* orconf ::= */ yytestcase(yyruleno==75);
+{yymsp[1].minor.yy502 = OE_Default;}
+        break;
+      case 74: /* onconf ::= ON CONFLICT resolvetype */
+{yymsp[-2].minor.yy502 = yymsp[0].minor.yy502;}
+        break;
+      case 77: /* resolvetype ::= IGNORE */
+{yymsp[0].minor.yy502 = OE_Ignore;}
+        break;
+      case 78: /* resolvetype ::= REPLACE */
+      case 174: /* insert_cmd ::= REPLACE */ yytestcase(yyruleno==174);
+{yymsp[0].minor.yy502 = OE_Replace;}
+        break;
+      case 79: /* cmd ::= DROP TABLE ifexists fullname */
+{
+  sqlite3DropTable(pParse, yymsp[0].minor.yy563, 0, yymsp[-1].minor.yy502);
+}
+        break;
+      case 82: /* cmd ::= createkw temp VIEW ifnotexists nm dbnm eidlist_opt AS select */
+{
+  sqlite3CreateView(pParse, &yymsp[-8].minor.yy0, &yymsp[-4].minor.yy0, &yymsp[-3].minor.yy0, yymsp[-2].minor.yy402, yymsp[0].minor.yy637, yymsp[-7].minor.yy502, yymsp[-5].minor.yy502);
+}
+        break;
+      case 83: /* cmd ::= DROP VIEW ifexists fullname */
+{
+  sqlite3DropTable(pParse, yymsp[0].minor.yy563, 1, yymsp[-1].minor.yy502);
+}
+        break;
+      case 84: /* cmd ::= select */
+{
+  SelectDest dest = {SRT_Output, 0, 0, 0, 0, 0, 0};
+  if( (pParse->db->mDbFlags & DBFLAG_EncodingFixed)!=0
+   || sqlite3ReadSchema(pParse)==SQLITE_OK
+  ){
+    sqlite3Select(pParse, yymsp[0].minor.yy637, &dest);
+  }
+  sqlite3SelectDelete(pParse->db, yymsp[0].minor.yy637);
+}
+        break;
+      case 85: /* select ::= WITH wqlist selectnowith */
+{yymsp[-2].minor.yy637 = attachWithToSelect(pParse,yymsp[0].minor.yy637,yymsp[-1].minor.yy125);}
+        break;
+      case 86: /* select ::= WITH RECURSIVE wqlist selectnowith */
+{yymsp[-3].minor.yy637 = attachWithToSelect(pParse,yymsp[0].minor.yy637,yymsp[-1].minor.yy125);}
+        break;
+      case 87: /* select ::= selectnowith */
+{
+  Select *p = yymsp[0].minor.yy637;
+  if( p ){
+    parserDoubleLinkSelect(pParse, p);
+  }
+}
+        break;
+      case 88: /* selectnowith ::= selectnowith multiselect_op oneselect */
+{
+  Select *pRhs = yymsp[0].minor.yy637;
+  Select *pLhs = yymsp[-2].minor.yy637;
+  if( pRhs && pRhs->pPrior ){
+    SrcList *pFrom;
+    Token x;
+    x.n = 0;
+    parserDoubleLinkSelect(pParse, pRhs);
+    pFrom = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&x,pRhs,0);
+    pRhs = sqlite3SelectNew(pParse,0,pFrom,0,0,0,0,0,0);
+  }
+  if( pRhs ){
+    pRhs->op = (u8)yymsp[-1].minor.yy502;
+    pRhs->pPrior = pLhs;
+    if( ALWAYS(pLhs) ) pLhs->selFlags &= ~SF_MultiValue;
+    pRhs->selFlags &= ~SF_MultiValue;
+    if( yymsp[-1].minor.yy502!=TK_ALL ) pParse->hasCompound = 1;
+  }else{
+    sqlite3SelectDelete(pParse->db, pLhs);
+  }
+  yymsp[-2].minor.yy637 = pRhs;
+}
+        break;
+      case 89: /* multiselect_op ::= UNION */
+      case 91: /* multiselect_op ::= EXCEPT|INTERSECT */ yytestcase(yyruleno==91);
+{yymsp[0].minor.yy502 = yymsp[0].major; /*A-overwrites-OP*/}
+        break;
+      case 90: /* multiselect_op ::= UNION ALL */
+{yymsp[-1].minor.yy502 = TK_ALL;}
+        break;
+      case 92: /* oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt orderby_opt limit_opt */
+{
+  yymsp[-8].minor.yy637 = sqlite3SelectNew(pParse,yymsp[-6].minor.yy402,yymsp[-5].minor.yy563,yymsp[-4].minor.yy590,yymsp[-3].minor.yy402,yymsp[-2].minor.yy590,yymsp[-1].minor.yy402,yymsp[-7].minor.yy502,yymsp[0].minor.yy590);
+}
+        break;
+      case 93: /* oneselect ::= SELECT distinct selcollist from where_opt groupby_opt having_opt window_clause orderby_opt limit_opt */
+{
+  yymsp[-9].minor.yy637 = sqlite3SelectNew(pParse,yymsp[-7].minor.yy402,yymsp[-6].minor.yy563,yymsp[-5].minor.yy590,yymsp[-4].minor.yy402,yymsp[-3].minor.yy590,yymsp[-1].minor.yy402,yymsp[-8].minor.yy502,yymsp[0].minor.yy590);
+  if( yymsp[-9].minor.yy637 ){
+    yymsp[-9].minor.yy637->pWinDefn = yymsp[-2].minor.yy483;
+  }else{
+    sqlite3WindowListDelete(pParse->db, yymsp[-2].minor.yy483);
+  }
+}
+        break;
+      case 94: /* values ::= VALUES LP nexprlist RP */
+{
+  yymsp[-3].minor.yy637 = sqlite3SelectNew(pParse,yymsp[-1].minor.yy402,0,0,0,0,0,SF_Values,0);
+}
+        break;
+      case 95: /* oneselect ::= mvalues */
+{
+  sqlite3MultiValuesEnd(pParse, yymsp[0].minor.yy637);
+}
+        break;
+      case 96: /* mvalues ::= values COMMA LP nexprlist RP */
+      case 97: /* mvalues ::= mvalues COMMA LP nexprlist RP */ yytestcase(yyruleno==97);
+{
+  yymsp[-4].minor.yy637 = sqlite3MultiValues(pParse, yymsp[-4].minor.yy637, yymsp[-1].minor.yy402);
+}
+        break;
+      case 98: /* distinct ::= DISTINCT */
+{yymsp[0].minor.yy502 = SF_Distinct;}
+        break;
+      case 99: /* distinct ::= ALL */
+{yymsp[0].minor.yy502 = SF_All;}
+        break;
+      case 101: /* sclp ::= */
+      case 134: /* orderby_opt ::= */ yytestcase(yyruleno==134);
+      case 144: /* groupby_opt ::= */ yytestcase(yyruleno==144);
+      case 234: /* exprlist ::= */ yytestcase(yyruleno==234);
+      case 237: /* paren_exprlist ::= */ yytestcase(yyruleno==237);
+      case 242: /* eidlist_opt ::= */ yytestcase(yyruleno==242);
+{yymsp[1].minor.yy402 = 0;}
+        break;
+      case 102: /* selcollist ::= sclp scanpt expr scanpt as */
+{
+   yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse, yymsp[-4].minor.yy402, yymsp[-2].minor.yy590);
+   if( yymsp[0].minor.yy0.n>0 ) sqlite3ExprListSetName(pParse, yymsp[-4].minor.yy402, &yymsp[0].minor.yy0, 1);
+   sqlite3ExprListSetSpan(pParse,yymsp[-4].minor.yy402,yymsp[-3].minor.yy342,yymsp[-1].minor.yy342);
+}
+        break;
+      case 103: /* selcollist ::= sclp scanpt STAR */
+{
+  Expr *p = sqlite3Expr(pParse->db, TK_ASTERISK, 0);
+  sqlite3ExprSetErrorOffset(p, (int)(yymsp[0].minor.yy0.z - pParse->zTail));
+  yymsp[-2].minor.yy402 = sqlite3ExprListAppend(pParse, yymsp[-2].minor.yy402, p);
+}
+        break;
+      case 104: /* selcollist ::= sclp scanpt nm DOT STAR */
+{
+  Expr *pRight, *pLeft, *pDot;
+  pRight = sqlite3PExpr(pParse, TK_ASTERISK, 0, 0);
+  sqlite3ExprSetErrorOffset(pRight, (int)(yymsp[0].minor.yy0.z - pParse->zTail));
+  pLeft = tokenExpr(pParse, TK_ID, yymsp[-2].minor.yy0);
+  pDot = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight);
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy402, pDot);
+}
+        break;
+      case 105: /* as ::= AS nm */
+      case 117: /* dbnm ::= DOT nm */ yytestcase(yyruleno==117);
+      case 258: /* plus_num ::= PLUS INTEGER|FLOAT */ yytestcase(yyruleno==258);
+      case 259: /* minus_num ::= MINUS INTEGER|FLOAT */ yytestcase(yyruleno==259);
+{yymsp[-1].minor.yy0 = yymsp[0].minor.yy0;}
+        break;
+      case 107: /* from ::= */
+      case 110: /* stl_prefix ::= */ yytestcase(yyruleno==110);
+{yymsp[1].minor.yy563 = 0;}
+        break;
+      case 108: /* from ::= FROM seltablist */
+{
+  yymsp[-1].minor.yy563 = yymsp[0].minor.yy563;
+  sqlite3SrcListShiftJoinType(pParse,yymsp[-1].minor.yy563);
+}
+        break;
+      case 109: /* stl_prefix ::= seltablist joinop */
+{
+   if( ALWAYS(yymsp[-1].minor.yy563 && yymsp[-1].minor.yy563->nSrc>0) ) yymsp[-1].minor.yy563->a[yymsp[-1].minor.yy563->nSrc-1].fg.jointype = (u8)yymsp[0].minor.yy502;
+}
+        break;
+      case 111: /* seltablist ::= stl_prefix nm dbnm as on_using */
+{
+  yymsp[-4].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-4].minor.yy563,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0,0,&yymsp[0].minor.yy421);
+}
+        break;
+      case 112: /* seltablist ::= stl_prefix nm dbnm as indexed_by on_using */
+{
+  yymsp[-5].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-5].minor.yy563,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,0,&yymsp[0].minor.yy421);
+  sqlite3SrcListIndexedBy(pParse, yymsp[-5].minor.yy563, &yymsp[-1].minor.yy0);
+}
+        break;
+      case 113: /* seltablist ::= stl_prefix nm dbnm LP exprlist RP as on_using */
+{
+  yymsp[-7].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-7].minor.yy563,&yymsp[-6].minor.yy0,&yymsp[-5].minor.yy0,&yymsp[-1].minor.yy0,0,&yymsp[0].minor.yy421);
+  sqlite3SrcListFuncArgs(pParse, yymsp[-7].minor.yy563, yymsp[-3].minor.yy402);
+}
+        break;
+      case 114: /* seltablist ::= stl_prefix LP select RP as on_using */
+{
+    yymsp[-5].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-5].minor.yy563,0,0,&yymsp[-1].minor.yy0,yymsp[-3].minor.yy637,&yymsp[0].minor.yy421);
+  }
+        break;
+      case 115: /* seltablist ::= stl_prefix LP seltablist RP as on_using */
+{
+    if( yymsp[-5].minor.yy563==0 && yymsp[-1].minor.yy0.n==0 && yymsp[0].minor.yy421.pOn==0 && yymsp[0].minor.yy421.pUsing==0 ){
+      yymsp[-5].minor.yy563 = yymsp[-3].minor.yy563;
+    }else if( ALWAYS(yymsp[-3].minor.yy563!=0) && yymsp[-3].minor.yy563->nSrc==1 ){
+      yymsp[-5].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-5].minor.yy563,0,0,&yymsp[-1].minor.yy0,0,&yymsp[0].minor.yy421);
+      if( yymsp[-5].minor.yy563 ){
+        SrcItem *pNew = &yymsp[-5].minor.yy563->a[yymsp[-5].minor.yy563->nSrc-1];
+        SrcItem *pOld = yymsp[-3].minor.yy563->a;
+        assert( pOld->fg.fixedSchema==0 );
+        pNew->zName = pOld->zName;
+        assert( pOld->fg.fixedSchema==0 );
+        if( pOld->fg.isSubquery ){
+          pNew->fg.isSubquery = 1;
+          pNew->u4.pSubq = pOld->u4.pSubq;
+          pOld->u4.pSubq = 0;
+          pOld->fg.isSubquery = 0;
+          assert( pNew->u4.pSubq!=0 && pNew->u4.pSubq->pSelect!=0 );
+          if( (pNew->u4.pSubq->pSelect->selFlags & SF_NestedFrom)!=0 ){
+            pNew->fg.isNestedFrom = 1;
+          }
+        }else{
+          pNew->u4.zDatabase = pOld->u4.zDatabase;
+          pOld->u4.zDatabase = 0;
+        }
+        if( pOld->fg.isTabFunc ){
+          pNew->u1.pFuncArg = pOld->u1.pFuncArg;
+          pOld->u1.pFuncArg = 0;
+          pOld->fg.isTabFunc = 0;
+          pNew->fg.isTabFunc = 1;
+        }
+        pOld->zName = 0;
+      }
+      sqlite3SrcListDelete(pParse->db, yymsp[-3].minor.yy563);
+    }else{
+      Select *pSubquery;
+      sqlite3SrcListShiftJoinType(pParse,yymsp[-3].minor.yy563);
+      pSubquery = sqlite3SelectNew(pParse,0,yymsp[-3].minor.yy563,0,0,0,0,SF_NestedFrom,0);
+      yymsp[-5].minor.yy563 = sqlite3SrcListAppendFromTerm(pParse,yymsp[-5].minor.yy563,0,0,&yymsp[-1].minor.yy0,pSubquery,&yymsp[0].minor.yy421);
+    }
+  }
+        break;
+      case 116: /* dbnm ::= */
+      case 131: /* indexed_opt ::= */ yytestcase(yyruleno==131);
+{yymsp[1].minor.yy0.z=0; yymsp[1].minor.yy0.n=0;}
+        break;
+      case 118: /* fullname ::= nm */
+{
+  yylhsminor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[0].minor.yy0,0);
+  if( IN_RENAME_OBJECT && yylhsminor.yy563 ) sqlite3RenameTokenMap(pParse, yylhsminor.yy563->a[0].zName, &yymsp[0].minor.yy0);
+}
+  yymsp[0].minor.yy563 = yylhsminor.yy563;
+        break;
+      case 119: /* fullname ::= nm DOT nm */
+{
+  yylhsminor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0);
+  if( IN_RENAME_OBJECT && yylhsminor.yy563 ) sqlite3RenameTokenMap(pParse, yylhsminor.yy563->a[0].zName, &yymsp[0].minor.yy0);
+}
+  yymsp[-2].minor.yy563 = yylhsminor.yy563;
+        break;
+      case 120: /* xfullname ::= nm */
+{yymsp[0].minor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[0].minor.yy0,0); /*A-overwrites-X*/}
+        break;
+      case 121: /* xfullname ::= nm DOT nm */
+{yymsp[-2].minor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0); /*A-overwrites-X*/}
+        break;
+      case 122: /* xfullname ::= nm DOT nm AS nm */
+{
+   yymsp[-4].minor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[-4].minor.yy0,&yymsp[-2].minor.yy0); /*A-overwrites-X*/
+   if( yymsp[-4].minor.yy563 ) yymsp[-4].minor.yy563->a[0].zAlias = sqlite3NameFromToken(pParse->db, &yymsp[0].minor.yy0);
+}
+        break;
+      case 123: /* xfullname ::= nm AS nm */
+{
+   yymsp[-2].minor.yy563 = sqlite3SrcListAppend(pParse,0,&yymsp[-2].minor.yy0,0); /*A-overwrites-X*/
+   if( yymsp[-2].minor.yy563 ) yymsp[-2].minor.yy563->a[0].zAlias = sqlite3NameFromToken(pParse->db, &yymsp[0].minor.yy0);
+}
+        break;
+      case 124: /* joinop ::= COMMA|JOIN */
+{ yymsp[0].minor.yy502 = JT_INNER; }
+        break;
+      case 125: /* joinop ::= JOIN_KW JOIN */
+{yymsp[-1].minor.yy502 = sqlite3JoinType(pParse,&yymsp[-1].minor.yy0,0,0);  /*X-overwrites-A*/}
+        break;
+      case 126: /* joinop ::= JOIN_KW nm JOIN */
+{yymsp[-2].minor.yy502 = sqlite3JoinType(pParse,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0,0); /*X-overwrites-A*/}
+        break;
+      case 127: /* joinop ::= JOIN_KW nm nm JOIN */
+{yymsp[-3].minor.yy502 = sqlite3JoinType(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0);/*X-overwrites-A*/}
+        break;
+      case 128: /* on_using ::= ON expr */
+{yymsp[-1].minor.yy421.pOn = yymsp[0].minor.yy590; yymsp[-1].minor.yy421.pUsing = 0;}
+        break;
+      case 129: /* on_using ::= USING LP idlist RP */
+{yymsp[-3].minor.yy421.pOn = 0; yymsp[-3].minor.yy421.pUsing = yymsp[-1].minor.yy204;}
+        break;
+      case 130: /* on_using ::= */
+{yymsp[1].minor.yy421.pOn = 0; yymsp[1].minor.yy421.pUsing = 0;}
+        break;
+      case 132: /* indexed_by ::= INDEXED BY nm */
+{yymsp[-2].minor.yy0 = yymsp[0].minor.yy0;}
+        break;
+      case 133: /* indexed_by ::= NOT INDEXED */
+{yymsp[-1].minor.yy0.z=0; yymsp[-1].minor.yy0.n=1;}
+        break;
+      case 135: /* orderby_opt ::= ORDER BY sortlist */
+      case 145: /* groupby_opt ::= GROUP BY nexprlist */ yytestcase(yyruleno==145);
+{yymsp[-2].minor.yy402 = yymsp[0].minor.yy402;}
+        break;
+      case 136: /* sortlist ::= sortlist COMMA expr sortorder nulls */
+{
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy402,yymsp[-2].minor.yy590);
+  sqlite3ExprListSetSortOrder(yymsp[-4].minor.yy402,yymsp[-1].minor.yy502,yymsp[0].minor.yy502);
+}
+        break;
+      case 137: /* sortlist ::= expr sortorder nulls */
+{
+  yymsp[-2].minor.yy402 = sqlite3ExprListAppend(pParse,0,yymsp[-2].minor.yy590); /*A-overwrites-Y*/
+  sqlite3ExprListSetSortOrder(yymsp[-2].minor.yy402,yymsp[-1].minor.yy502,yymsp[0].minor.yy502);
+}
+        break;
+      case 138: /* sortorder ::= ASC */
+{yymsp[0].minor.yy502 = SQLITE_SO_ASC;}
+        break;
+      case 139: /* sortorder ::= DESC */
+{yymsp[0].minor.yy502 = SQLITE_SO_DESC;}
+        break;
+      case 140: /* sortorder ::= */
+      case 143: /* nulls ::= */ yytestcase(yyruleno==143);
+{yymsp[1].minor.yy502 = SQLITE_SO_UNDEFINED;}
+        break;
+      case 141: /* nulls ::= NULLS FIRST */
+{yymsp[-1].minor.yy502 = SQLITE_SO_ASC;}
+        break;
+      case 142: /* nulls ::= NULLS LAST */
+{yymsp[-1].minor.yy502 = SQLITE_SO_DESC;}
+        break;
+      case 146: /* having_opt ::= */
+      case 148: /* limit_opt ::= */ yytestcase(yyruleno==148);
+      case 153: /* where_opt ::= */ yytestcase(yyruleno==153);
+      case 155: /* where_opt_ret ::= */ yytestcase(yyruleno==155);
+      case 232: /* case_else ::= */ yytestcase(yyruleno==232);
+      case 233: /* case_operand ::= */ yytestcase(yyruleno==233);
+      case 252: /* vinto ::= */ yytestcase(yyruleno==252);
+{yymsp[1].minor.yy590 = 0;}
+        break;
+      case 147: /* having_opt ::= HAVING expr */
+      case 154: /* where_opt ::= WHERE expr */ yytestcase(yyruleno==154);
+      case 156: /* where_opt_ret ::= WHERE expr */ yytestcase(yyruleno==156);
+      case 231: /* case_else ::= ELSE expr */ yytestcase(yyruleno==231);
+      case 251: /* vinto ::= INTO expr */ yytestcase(yyruleno==251);
+{yymsp[-1].minor.yy590 = yymsp[0].minor.yy590;}
+        break;
+      case 149: /* limit_opt ::= LIMIT expr */
+{yymsp[-1].minor.yy590 = sqlite3PExpr(pParse,TK_LIMIT,yymsp[0].minor.yy590,0);}
+        break;
+      case 150: /* limit_opt ::= LIMIT expr OFFSET expr */
+{yymsp[-3].minor.yy590 = sqlite3PExpr(pParse,TK_LIMIT,yymsp[-2].minor.yy590,yymsp[0].minor.yy590);}
+        break;
+      case 151: /* limit_opt ::= LIMIT expr COMMA expr */
+{yymsp[-3].minor.yy590 = sqlite3PExpr(pParse,TK_LIMIT,yymsp[0].minor.yy590,yymsp[-2].minor.yy590);}
+        break;
+      case 152: /* cmd ::= with DELETE FROM xfullname indexed_opt where_opt_ret orderby_opt limit_opt */
+{
+  sqlite3SrcListIndexedBy(pParse, yymsp[-4].minor.yy563, &yymsp[-3].minor.yy0);
+#ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( yymsp[-1].minor.yy402 || yymsp[0].minor.yy590 ){
+    updateDeleteLimitError(pParse,yymsp[-1].minor.yy402,yymsp[0].minor.yy590);
+    yymsp[-1].minor.yy402 = 0;
+    yymsp[0].minor.yy590 = 0;
+  }
+#endif
+  sqlite3DeleteFrom(pParse,yymsp[-4].minor.yy563,yymsp[-2].minor.yy590,yymsp[-1].minor.yy402,yymsp[0].minor.yy590);
+}
+        break;
+      case 157: /* where_opt_ret ::= RETURNING selcollist */
+{sqlite3AddReturning(pParse,yymsp[0].minor.yy402); yymsp[-1].minor.yy590 = 0;}
+        break;
+      case 158: /* where_opt_ret ::= WHERE expr RETURNING selcollist */
+{sqlite3AddReturning(pParse,yymsp[0].minor.yy402); yymsp[-3].minor.yy590 = yymsp[-2].minor.yy590;}
+        break;
+      case 159: /* cmd ::= with UPDATE orconf xfullname indexed_opt SET setlist from where_opt_ret orderby_opt limit_opt */
+{
+  sqlite3SrcListIndexedBy(pParse, yymsp[-7].minor.yy563, &yymsp[-6].minor.yy0);
+  if( yymsp[-3].minor.yy563 ){
+    SrcList *pFromClause = yymsp[-3].minor.yy563;
+    if( pFromClause->nSrc>1 ){
+      Select *pSubquery;
+      Token as;
+      pSubquery = sqlite3SelectNew(pParse,0,pFromClause,0,0,0,0,SF_NestedFrom,0);
+      as.n = 0;
+      as.z = 0;
+      pFromClause = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&as,pSubquery,0);
+    }
+    yymsp[-7].minor.yy563 = sqlite3SrcListAppendList(pParse, yymsp[-7].minor.yy563, pFromClause);
+  }
+  sqlite3ExprListCheckLength(pParse,yymsp[-4].minor.yy402,"set list");
+#ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
+  if( yymsp[-1].minor.yy402 || yymsp[0].minor.yy590 ){
+    updateDeleteLimitError(pParse,yymsp[-1].minor.yy402,yymsp[0].minor.yy590);
+    yymsp[-1].minor.yy402 = 0;
+    yymsp[0].minor.yy590 = 0;
+  }
+#endif
+  sqlite3Update(pParse,yymsp[-7].minor.yy563,yymsp[-4].minor.yy402,yymsp[-2].minor.yy590,yymsp[-8].minor.yy502,yymsp[-1].minor.yy402,yymsp[0].minor.yy590,0);
+}
+        break;
+      case 160: /* setlist ::= setlist COMMA nm EQ expr */
+{
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse, yymsp[-4].minor.yy402, yymsp[0].minor.yy590);
+  sqlite3ExprListSetName(pParse, yymsp[-4].minor.yy402, &yymsp[-2].minor.yy0, 1);
+}
+        break;
+      case 161: /* setlist ::= setlist COMMA LP idlist RP EQ expr */
+{
+  yymsp[-6].minor.yy402 = sqlite3ExprListAppendVector(pParse, yymsp[-6].minor.yy402, yymsp[-3].minor.yy204, yymsp[0].minor.yy590);
+}
+        break;
+      case 162: /* setlist ::= nm EQ expr */
+{
+  yylhsminor.yy402 = sqlite3ExprListAppend(pParse, 0, yymsp[0].minor.yy590);
+  sqlite3ExprListSetName(pParse, yylhsminor.yy402, &yymsp[-2].minor.yy0, 1);
+}
+  yymsp[-2].minor.yy402 = yylhsminor.yy402;
+        break;
+      case 163: /* setlist ::= LP idlist RP EQ expr */
+{
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppendVector(pParse, 0, yymsp[-3].minor.yy204, yymsp[0].minor.yy590);
+}
+        break;
+      case 164: /* cmd ::= with insert_cmd INTO xfullname idlist_opt select upsert */
+{
+  sqlite3Insert(pParse, yymsp[-3].minor.yy563, yymsp[-1].minor.yy637, yymsp[-2].minor.yy204, yymsp[-5].minor.yy502, yymsp[0].minor.yy403);
+}
+        break;
+      case 165: /* cmd ::= with insert_cmd INTO xfullname idlist_opt DEFAULT VALUES returning */
+{
+  sqlite3Insert(pParse, yymsp[-4].minor.yy563, 0, yymsp[-3].minor.yy204, yymsp[-6].minor.yy502, 0);
+}
+        break;
+      case 166: /* upsert ::= */
+{ yymsp[1].minor.yy403 = 0; }
+        break;
+      case 167: /* upsert ::= RETURNING selcollist */
+{ yymsp[-1].minor.yy403 = 0; sqlite3AddReturning(pParse,yymsp[0].minor.yy402); }
+        break;
+      case 168: /* upsert ::= ON CONFLICT LP sortlist RP where_opt DO UPDATE SET setlist where_opt upsert */
+{ yymsp[-11].minor.yy403 = sqlite3UpsertNew(pParse->db,yymsp[-8].minor.yy402,yymsp[-6].minor.yy590,yymsp[-2].minor.yy402,yymsp[-1].minor.yy590,yymsp[0].minor.yy403);}
+        break;
+      case 169: /* upsert ::= ON CONFLICT LP sortlist RP where_opt DO NOTHING upsert */
+{ yymsp[-8].minor.yy403 = sqlite3UpsertNew(pParse->db,yymsp[-5].minor.yy402,yymsp[-3].minor.yy590,0,0,yymsp[0].minor.yy403); }
+        break;
+      case 170: /* upsert ::= ON CONFLICT DO NOTHING returning */
+{ yymsp[-4].minor.yy403 = sqlite3UpsertNew(pParse->db,0,0,0,0,0); }
+        break;
+      case 171: /* upsert ::= ON CONFLICT DO UPDATE SET setlist where_opt returning */
+{ yymsp[-7].minor.yy403 = sqlite3UpsertNew(pParse->db,0,0,yymsp[-2].minor.yy402,yymsp[-1].minor.yy590,0);}
+        break;
+      case 172: /* returning ::= RETURNING selcollist */
+{sqlite3AddReturning(pParse,yymsp[0].minor.yy402);}
+        break;
+      case 175: /* idlist_opt ::= */
+{yymsp[1].minor.yy204 = 0;}
+        break;
+      case 176: /* idlist_opt ::= LP idlist RP */
+{yymsp[-2].minor.yy204 = yymsp[-1].minor.yy204;}
+        break;
+      case 177: /* idlist ::= idlist COMMA nm */
+{yymsp[-2].minor.yy204 = sqlite3IdListAppend(pParse,yymsp[-2].minor.yy204,&yymsp[0].minor.yy0);}
+        break;
+      case 178: /* idlist ::= nm */
+{yymsp[0].minor.yy204 = sqlite3IdListAppend(pParse,0,&yymsp[0].minor.yy0); /*A-overwrites-Y*/}
+        break;
+      case 179: /* expr ::= LP expr RP */
+{yymsp[-2].minor.yy590 = yymsp[-1].minor.yy590;}
+        break;
+      case 180: /* expr ::= ID|INDEXED|JOIN_KW */
+{yymsp[0].minor.yy590=tokenExpr(pParse,TK_ID,yymsp[0].minor.yy0); /*A-overwrites-X*/}
+        break;
+      case 181: /* expr ::= nm DOT nm */
+{
+  Expr *temp1 = tokenExpr(pParse,TK_ID,yymsp[-2].minor.yy0);
+  Expr *temp2 = tokenExpr(pParse,TK_ID,yymsp[0].minor.yy0);
+  yylhsminor.yy590 = sqlite3PExpr(pParse, TK_DOT, temp1, temp2);
+}
+  yymsp[-2].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 182: /* expr ::= nm DOT nm DOT nm */
+{
+  Expr *temp1 = tokenExpr(pParse,TK_ID,yymsp[-4].minor.yy0);
+  Expr *temp2 = tokenExpr(pParse,TK_ID,yymsp[-2].minor.yy0);
+  Expr *temp3 = tokenExpr(pParse,TK_ID,yymsp[0].minor.yy0);
+  Expr *temp4 = sqlite3PExpr(pParse, TK_DOT, temp2, temp3);
+  if( IN_RENAME_OBJECT ){
+    sqlite3RenameTokenRemap(pParse, 0, temp1);
+  }
+  yylhsminor.yy590 = sqlite3PExpr(pParse, TK_DOT, temp1, temp4);
+}
+  yymsp[-4].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 183: /* term ::= NULL|FLOAT|BLOB */
+      case 184: /* term ::= STRING */ yytestcase(yyruleno==184);
+{yymsp[0].minor.yy590=tokenExpr(pParse,yymsp[0].major,yymsp[0].minor.yy0); /*A-overwrites-X*/}
+        break;
+      case 185: /* term ::= INTEGER */
+{
+  yylhsminor.yy590 = sqlite3ExprAlloc(pParse->db, TK_INTEGER, &yymsp[0].minor.yy0, 1);
+  if( yylhsminor.yy590 ) yylhsminor.yy590->w.iOfst = (int)(yymsp[0].minor.yy0.z - pParse->zTail);
+}
+  yymsp[0].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 186: /* expr ::= VARIABLE */
+{
+  if( !(yymsp[0].minor.yy0.z[0]=='#' && sqlite3Isdigit(yymsp[0].minor.yy0.z[1])) ){
+    u32 n = yymsp[0].minor.yy0.n;
+    yymsp[0].minor.yy590 = tokenExpr(pParse, TK_VARIABLE, yymsp[0].minor.yy0);
+    sqlite3ExprAssignVarNumber(pParse, yymsp[0].minor.yy590, n);
+  }else{
+    /* When doing a nested parse, one can include terms in an expression
+    ** that look like this:   #1 #2 ...  These terms refer to registers
+    ** in the virtual machine.  #N is the N-th register. */
+    Token t = yymsp[0].minor.yy0; /*A-overwrites-X*/
+    assert( t.n>=2 );
+    if( pParse->nested==0 ){
+      parserSyntaxError(pParse, &t);
+      yymsp[0].minor.yy590 = 0;
+    }else{
+      yymsp[0].minor.yy590 = sqlite3PExpr(pParse, TK_REGISTER, 0, 0);
+      if( yymsp[0].minor.yy590 ) sqlite3GetInt32(&t.z[1], &yymsp[0].minor.yy590->iTable);
+    }
+  }
+}
+        break;
+      case 187: /* expr ::= expr COLLATE ID|STRING */
+{
+  yymsp[-2].minor.yy590 = sqlite3ExprAddCollateToken(pParse, yymsp[-2].minor.yy590, &yymsp[0].minor.yy0, 1);
+}
+        break;
+      case 188: /* expr ::= CAST LP expr AS typetoken RP */
+{
+  yymsp[-5].minor.yy590 = sqlite3ExprAlloc(pParse->db, TK_CAST, &yymsp[-1].minor.yy0, 1);
+  sqlite3ExprAttachSubtrees(pParse->db, yymsp[-5].minor.yy590, yymsp[-3].minor.yy590, 0);
+}
+        break;
+      case 189: /* expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, yymsp[-1].minor.yy402, &yymsp[-4].minor.yy0, yymsp[-2].minor.yy502);
+}
+  yymsp[-4].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 190: /* expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, yymsp[-4].minor.yy402, &yymsp[-7].minor.yy0, yymsp[-5].minor.yy502);
+  sqlite3ExprAddFunctionOrderBy(pParse, yylhsminor.yy590, yymsp[-1].minor.yy402);
+}
+  yymsp[-7].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 191: /* expr ::= ID|INDEXED|JOIN_KW LP STAR RP */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, 0, &yymsp[-3].minor.yy0, 0);
+}
+  yymsp[-3].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 192: /* expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist RP filter_over */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, yymsp[-2].minor.yy402, &yymsp[-5].minor.yy0, yymsp[-3].minor.yy502);
+  sqlite3WindowAttach(pParse, yylhsminor.yy590, yymsp[0].minor.yy483);
+}
+  yymsp[-5].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 193: /* expr ::= ID|INDEXED|JOIN_KW LP distinct exprlist ORDER BY sortlist RP filter_over */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, yymsp[-5].minor.yy402, &yymsp[-8].minor.yy0, yymsp[-6].minor.yy502);
+  sqlite3WindowAttach(pParse, yylhsminor.yy590, yymsp[0].minor.yy483);
+  sqlite3ExprAddFunctionOrderBy(pParse, yylhsminor.yy590, yymsp[-2].minor.yy402);
+}
+  yymsp[-8].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 194: /* expr ::= ID|INDEXED|JOIN_KW LP STAR RP filter_over */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, 0, &yymsp[-4].minor.yy0, 0);
+  sqlite3WindowAttach(pParse, yylhsminor.yy590, yymsp[0].minor.yy483);
+}
+  yymsp[-4].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 195: /* term ::= CTIME_KW */
+{
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, 0, &yymsp[0].minor.yy0, 0);
+}
+  yymsp[0].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 196: /* expr ::= LP nexprlist COMMA expr RP */
+{
+  ExprList *pList = sqlite3ExprListAppend(pParse, yymsp[-3].minor.yy402, yymsp[-1].minor.yy590);
+  yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_VECTOR, 0, 0);
+  if( yymsp[-4].minor.yy590 ){
+    yymsp[-4].minor.yy590->x.pList = pList;
+    if( ALWAYS(pList->nExpr) ){
+      yymsp[-4].minor.yy590->flags |= pList->a[0].pExpr->flags & EP_Propagate;
+    }
+  }else{
+    sqlite3ExprListDelete(pParse->db, pList);
+  }
+}
+        break;
+      case 197: /* expr ::= expr AND expr */
+{yymsp[-2].minor.yy590=sqlite3ExprAnd(pParse,yymsp[-2].minor.yy590,yymsp[0].minor.yy590);}
+        break;
+      case 198: /* expr ::= expr OR expr */
+      case 199: /* expr ::= expr LT|GT|GE|LE expr */ yytestcase(yyruleno==199);
+      case 200: /* expr ::= expr EQ|NE expr */ yytestcase(yyruleno==200);
+      case 201: /* expr ::= expr BITAND|BITOR|LSHIFT|RSHIFT expr */ yytestcase(yyruleno==201);
+      case 202: /* expr ::= expr PLUS|MINUS expr */ yytestcase(yyruleno==202);
+      case 203: /* expr ::= expr STAR|SLASH|REM expr */ yytestcase(yyruleno==203);
+      case 204: /* expr ::= expr CONCAT expr */ yytestcase(yyruleno==204);
+{yymsp[-2].minor.yy590=sqlite3PExpr(pParse,yymsp[-1].major,yymsp[-2].minor.yy590,yymsp[0].minor.yy590);}
+        break;
+      case 205: /* likeop ::= NOT LIKE_KW|MATCH */
+{yymsp[-1].minor.yy0=yymsp[0].minor.yy0; yymsp[-1].minor.yy0.n|=0x80000000; /*yymsp[-1].minor.yy0-overwrite-yymsp[0].minor.yy0*/}
+        break;
+      case 206: /* expr ::= expr likeop expr */
+{
+  ExprList *pList;
+  int bNot = yymsp[-1].minor.yy0.n & 0x80000000;
+  yymsp[-1].minor.yy0.n &= 0x7fffffff;
+  pList = sqlite3ExprListAppend(pParse,0, yymsp[0].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[-2].minor.yy590);
+  yymsp[-2].minor.yy590 = sqlite3ExprFunction(pParse, pList, &yymsp[-1].minor.yy0, 0);
+  if( bNot ) yymsp[-2].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-2].minor.yy590, 0);
+  if( yymsp[-2].minor.yy590 ) yymsp[-2].minor.yy590->flags |= EP_InfixFunc;
+}
+        break;
+      case 207: /* expr ::= expr likeop expr ESCAPE expr */
+{
+  ExprList *pList;
+  int bNot = yymsp[-3].minor.yy0.n & 0x80000000;
+  yymsp[-3].minor.yy0.n &= 0x7fffffff;
+  pList = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[-4].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy590);
+  yymsp[-4].minor.yy590 = sqlite3ExprFunction(pParse, pList, &yymsp[-3].minor.yy0, 0);
+  if( bNot ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+  if( yymsp[-4].minor.yy590 ) yymsp[-4].minor.yy590->flags |= EP_InfixFunc;
+}
+        break;
+      case 208: /* expr ::= expr ISNULL|NOTNULL */
+{yymsp[-1].minor.yy590 = sqlite3PExpr(pParse,yymsp[0].major,yymsp[-1].minor.yy590,0);}
+        break;
+      case 209: /* expr ::= expr NOT NULL */
+{yymsp[-2].minor.yy590 = sqlite3PExpr(pParse,TK_NOTNULL,yymsp[-2].minor.yy590,0);}
+        break;
+      case 210: /* expr ::= expr IS expr */
+{
+  yymsp[-2].minor.yy590 = sqlite3PExpr(pParse,TK_IS,yymsp[-2].minor.yy590,yymsp[0].minor.yy590);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy590, yymsp[-2].minor.yy590, TK_ISNULL);
+}
+        break;
+      case 211: /* expr ::= expr IS NOT expr */
+{
+  yymsp[-3].minor.yy590 = sqlite3PExpr(pParse,TK_ISNOT,yymsp[-3].minor.yy590,yymsp[0].minor.yy590);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy590, yymsp[-3].minor.yy590, TK_NOTNULL);
+}
+        break;
+      case 212: /* expr ::= expr IS NOT DISTINCT FROM expr */
+{
+  yymsp[-5].minor.yy590 = sqlite3PExpr(pParse,TK_IS,yymsp[-5].minor.yy590,yymsp[0].minor.yy590);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy590, yymsp[-5].minor.yy590, TK_ISNULL);
+}
+        break;
+      case 213: /* expr ::= expr IS DISTINCT FROM expr */
+{
+  yymsp[-4].minor.yy590 = sqlite3PExpr(pParse,TK_ISNOT,yymsp[-4].minor.yy590,yymsp[0].minor.yy590);
+  binaryToUnaryIfNull(pParse, yymsp[0].minor.yy590, yymsp[-4].minor.yy590, TK_NOTNULL);
+}
+        break;
+      case 214: /* expr ::= NOT expr */
+      case 215: /* expr ::= BITNOT expr */ yytestcase(yyruleno==215);
+{yymsp[-1].minor.yy590 = sqlite3PExpr(pParse, yymsp[-1].major, yymsp[0].minor.yy590, 0);/*A-overwrites-B*/}
+        break;
+      case 216: /* expr ::= PLUS|MINUS expr */
+{
+  Expr *p = yymsp[0].minor.yy590;
+  u8 op = yymsp[-1].major + (TK_UPLUS-TK_PLUS);
+  assert( TK_UPLUS>TK_PLUS );
+  assert( TK_UMINUS == TK_MINUS + (TK_UPLUS - TK_PLUS) );
+  if( p && p->op==TK_UPLUS ){
+    p->op = op;
+    yymsp[-1].minor.yy590 = p;
+  }else{
+    yymsp[-1].minor.yy590 = sqlite3PExpr(pParse, op, p, 0);
+    /*A-overwrites-B*/
+  }
+}
+        break;
+      case 217: /* expr ::= expr PTR expr */
+{
+  ExprList *pList = sqlite3ExprListAppend(pParse, 0, yymsp[-2].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse, pList, yymsp[0].minor.yy590);
+  yylhsminor.yy590 = sqlite3ExprFunction(pParse, pList, &yymsp[-1].minor.yy0, 0);
+}
+  yymsp[-2].minor.yy590 = yylhsminor.yy590;
+        break;
+      case 218: /* between_op ::= BETWEEN */
+      case 221: /* in_op ::= IN */ yytestcase(yyruleno==221);
+{yymsp[0].minor.yy502 = 0;}
+        break;
+      case 220: /* expr ::= expr between_op expr AND expr */
+{
+  ExprList *pList = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy590);
+  pList = sqlite3ExprListAppend(pParse,pList, yymsp[0].minor.yy590);
+  yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_BETWEEN, yymsp[-4].minor.yy590, 0);
+  if( yymsp[-4].minor.yy590 ){
+    yymsp[-4].minor.yy590->x.pList = pList;
+  }else{
+    sqlite3ExprListDelete(pParse->db, pList);
+  }
+  if( yymsp[-3].minor.yy502 ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+}
+        break;
+      case 223: /* expr ::= expr in_op LP exprlist RP */
+{
+    if( yymsp[-1].minor.yy402==0 ){
+      /* Expressions of the form
+      **
+      **      expr1 IN ()
+      **      expr1 NOT IN ()
+      **
+      ** simplify to constants 0 (false) and 1 (true), respectively,
+      ** regardless of the value of expr1.
+      */
+      sqlite3ExprUnmapAndDelete(pParse, yymsp[-4].minor.yy590);
+      yymsp[-4].minor.yy590 = sqlite3Expr(pParse->db, TK_STRING, yymsp[-3].minor.yy502 ? "true" : "false");
+      if( yymsp[-4].minor.yy590 ) sqlite3ExprIdToTrueFalse(yymsp[-4].minor.yy590);
+    }else{
+      Expr *pRHS = yymsp[-1].minor.yy402->a[0].pExpr;
+      if( yymsp[-1].minor.yy402->nExpr==1 && sqlite3ExprIsConstant(pParse,pRHS) && yymsp[-4].minor.yy590->op!=TK_VECTOR ){
+        yymsp[-1].minor.yy402->a[0].pExpr = 0;
+        sqlite3ExprListDelete(pParse->db, yymsp[-1].minor.yy402);
+        pRHS = sqlite3PExpr(pParse, TK_UPLUS, pRHS, 0);
+        yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_EQ, yymsp[-4].minor.yy590, pRHS);
+      }else if( yymsp[-1].minor.yy402->nExpr==1 && pRHS->op==TK_SELECT ){
+        yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy590, 0);
+        sqlite3PExprAddSelect(pParse, yymsp[-4].minor.yy590, pRHS->x.pSelect);
+        pRHS->x.pSelect = 0;
+        sqlite3ExprListDelete(pParse->db, yymsp[-1].minor.yy402);
+      }else{
+        yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy590, 0);
+        if( yymsp[-4].minor.yy590==0 ){
+          sqlite3ExprListDelete(pParse->db, yymsp[-1].minor.yy402);
+        }else if( yymsp[-4].minor.yy590->pLeft->op==TK_VECTOR ){
+          int nExpr = yymsp[-4].minor.yy590->pLeft->x.pList->nExpr;
+          Select *pSelectRHS = sqlite3ExprListToValues(pParse, nExpr, yymsp[-1].minor.yy402);
+          if( pSelectRHS ){
+            parserDoubleLinkSelect(pParse, pSelectRHS);
+            sqlite3PExprAddSelect(pParse, yymsp[-4].minor.yy590, pSelectRHS);
+          }
+        }else{
+          yymsp[-4].minor.yy590->x.pList = yymsp[-1].minor.yy402;
+          sqlite3ExprSetHeightAndFlags(pParse, yymsp[-4].minor.yy590);
+        }
+      }
+      if( yymsp[-3].minor.yy502 ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+    }
+  }
+        break;
+      case 224: /* expr ::= LP select RP */
+{
+    yymsp[-2].minor.yy590 = sqlite3PExpr(pParse, TK_SELECT, 0, 0);
+    sqlite3PExprAddSelect(pParse, yymsp[-2].minor.yy590, yymsp[-1].minor.yy637);
+  }
+        break;
+      case 225: /* expr ::= expr in_op LP select RP */
+{
+    yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy590, 0);
+    sqlite3PExprAddSelect(pParse, yymsp[-4].minor.yy590, yymsp[-1].minor.yy637);
+    if( yymsp[-3].minor.yy502 ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+  }
+        break;
+      case 226: /* expr ::= expr in_op nm dbnm paren_exprlist */
+{
+    SrcList *pSrc = sqlite3SrcListAppend(pParse, 0,&yymsp[-2].minor.yy0,&yymsp[-1].minor.yy0);
+    Select *pSelect = sqlite3SelectNew(pParse, 0,pSrc,0,0,0,0,0,0);
+    if( yymsp[0].minor.yy402 )  sqlite3SrcListFuncArgs(pParse, pSelect ? pSrc : 0, yymsp[0].minor.yy402);
+    yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_IN, yymsp[-4].minor.yy590, 0);
+    sqlite3PExprAddSelect(pParse, yymsp[-4].minor.yy590, pSelect);
+    if( yymsp[-3].minor.yy502 ) yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_NOT, yymsp[-4].minor.yy590, 0);
+  }
+        break;
+      case 227: /* expr ::= EXISTS LP select RP */
+{
+    Expr *p;
+    p = yymsp[-3].minor.yy590 = sqlite3PExpr(pParse, TK_EXISTS, 0, 0);
+    sqlite3PExprAddSelect(pParse, p, yymsp[-1].minor.yy637);
+  }
+        break;
+      case 228: /* expr ::= CASE case_operand case_exprlist case_else END */
+{
+  yymsp[-4].minor.yy590 = sqlite3PExpr(pParse, TK_CASE, yymsp[-3].minor.yy590, 0);
+  if( yymsp[-4].minor.yy590 ){
+    yymsp[-4].minor.yy590->x.pList = yymsp[-1].minor.yy590 ? sqlite3ExprListAppend(pParse,yymsp[-2].minor.yy402,yymsp[-1].minor.yy590) : yymsp[-2].minor.yy402;
+    sqlite3ExprSetHeightAndFlags(pParse, yymsp[-4].minor.yy590);
+  }else{
+    sqlite3ExprListDelete(pParse->db, yymsp[-2].minor.yy402);
+    sqlite3ExprDelete(pParse->db, yymsp[-1].minor.yy590);
+  }
+}
+        break;
+      case 229: /* case_exprlist ::= case_exprlist WHEN expr THEN expr */
+{
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy402, yymsp[-2].minor.yy590);
+  yymsp[-4].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy402, yymsp[0].minor.yy590);
+}
+        break;
+      case 230: /* case_exprlist ::= WHEN expr THEN expr */
+{
+  yymsp[-3].minor.yy402 = sqlite3ExprListAppend(pParse,0, yymsp[-2].minor.yy590);
+  yymsp[-3].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-3].minor.yy402, yymsp[0].minor.yy590);
+}
+        break;
+      case 235: /* nexprlist ::= nexprlist COMMA expr */
+{yymsp[-2].minor.yy402 = sqlite3ExprListAppend(pParse,yymsp[-2].minor.yy402,yymsp[0].minor.yy590);}
+        break;
+      case 236: /* nexprlist ::= expr */
+{yymsp[0].minor.yy402 = sqlite3ExprListAppend(pParse,0,yymsp[0].minor.yy590); /*A-overwrites-Y*/}
+        break;
+      case 238: /* paren_exprlist ::= LP exprlist RP */
+      case 243: /* eidlist_opt ::= LP eidlist RP */ yytestcase(yyruleno==243);
+{yymsp[-2].minor.yy402 = yymsp[-1].minor.yy402;}
+        break;
+      case 239: /* cmd ::= createkw uniqueflag INDEX ifnotexists nm dbnm ON nm LP sortlist RP where_opt */
+{
+  sqlite3CreateIndex(pParse, &yymsp[-7].minor.yy0, &yymsp[-6].minor.yy0,
+                     sqlite3SrcListAppend(pParse,0,&yymsp[-4].minor.yy0,0), yymsp[-2].minor.yy402, yymsp[-10].minor.yy502,
+                      &yymsp[-11].minor.yy0, yymsp[0].minor.yy590, SQLITE_SO_ASC, yymsp[-8].minor.yy502, SQLITE_IDXTYPE_APPDEF);
+  if( IN_RENAME_OBJECT && pParse->pNewIndex ){
+    sqlite3RenameTokenMap(pParse, pParse->pNewIndex->zName, &yymsp[-4].minor.yy0);
+  }
+}
+        break;
+      case 240: /* uniqueflag ::= UNIQUE */
+      case 282: /* raisetype ::= ABORT */ yytestcase(yyruleno==282);
+{yymsp[0].minor.yy502 = OE_Abort;}
+        break;
+      case 241: /* uniqueflag ::= */
+{yymsp[1].minor.yy502 = OE_None;}
+        break;
+      case 244: /* eidlist ::= eidlist COMMA nm collate sortorder */
+{
+  yymsp[-4].minor.yy402 = parserAddExprIdListTerm(pParse, yymsp[-4].minor.yy402, &yymsp[-2].minor.yy0, yymsp[-1].minor.yy502, yymsp[0].minor.yy502);
+}
+        break;
+      case 245: /* eidlist ::= nm collate sortorder */
+{
+  yymsp[-2].minor.yy402 = parserAddExprIdListTerm(pParse, 0, &yymsp[-2].minor.yy0, yymsp[-1].minor.yy502, yymsp[0].minor.yy502); /*A-overwrites-Y*/
+}
+        break;
+      case 248: /* cmd ::= DROP INDEX ifexists fullname */
+{sqlite3DropIndex(pParse, yymsp[0].minor.yy563, yymsp[-1].minor.yy502);}
+        break;
+      case 249: /* cmd ::= VACUUM vinto */
+{sqlite3Vacuum(pParse,0,yymsp[0].minor.yy590);}
+        break;
+      case 250: /* cmd ::= VACUUM nm vinto */
+{sqlite3Vacuum(pParse,&yymsp[-1].minor.yy0,yymsp[0].minor.yy590);}
+        break;
+      case 253: /* cmd ::= PRAGMA nm dbnm */
+{sqlite3Pragma(pParse,&yymsp[-1].minor.yy0,&yymsp[0].minor.yy0,0,0);}
+        break;
+      case 254: /* cmd ::= PRAGMA nm dbnm EQ nmnum */
+{sqlite3Pragma(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0,0);}
+        break;
+      case 255: /* cmd ::= PRAGMA nm dbnm LP nmnum RP */
+{sqlite3Pragma(pParse,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,&yymsp[-1].minor.yy0,0);}
+        break;
+      case 256: /* cmd ::= PRAGMA nm dbnm EQ minus_num */
+{sqlite3Pragma(pParse,&yymsp[-3].minor.yy0,&yymsp[-2].minor.yy0,&yymsp[0].minor.yy0,1);}
+        break;
+      case 257: /* cmd ::= PRAGMA nm dbnm LP minus_num RP */
+{sqlite3Pragma(pParse,&yymsp[-4].minor.yy0,&yymsp[-3].minor.yy0,&yymsp[-1].minor.yy0,1);}
+        break;
+      case 260: /* cmd ::= createkw trigger_decl BEGIN trigger_cmd_list END */
+{
+  Token all;
+  all.z = yymsp[-3].minor.yy0.z;
+  all.n = (int)(yymsp[0].minor.yy0.z - yymsp[-3].minor.yy0.z) + yymsp[0].minor.yy0.n;
+  sqlite3FinishTrigger(pParse, yymsp[-1].minor.yy319, &all);
+}
+        break;
+      case 261: /* trigger_decl ::= temp TRIGGER ifnotexists nm dbnm trigger_time trigger_event ON fullname foreach_clause when_clause */
+{
+  sqlite3BeginTrigger(pParse, &yymsp[-7].minor.yy0, &yymsp[-6].minor.yy0, yymsp[-5].minor.yy502, yymsp[-4].minor.yy28.a, yymsp[-4].minor.yy28.b, yymsp[-2].minor.yy563, yymsp[0].minor.yy590, yymsp[-10].minor.yy502, yymsp[-8].minor.yy502);
+  yymsp[-10].minor.yy0 = (yymsp[-6].minor.yy0.n==0?yymsp[-7].minor.yy0:yymsp[-6].minor.yy0); /*A-overwrites-T*/
+}
+        break;
+      case 262: /* trigger_time ::= BEFORE|AFTER */
+{ yymsp[0].minor.yy502 = yymsp[0].major; /*A-overwrites-X*/ }
+        break;
+      case 263: /* trigger_time ::= INSTEAD OF */
+{ yymsp[-1].minor.yy502 = TK_INSTEAD;}
+        break;
+      case 264: /* trigger_time ::= */
+{ yymsp[1].minor.yy502 = TK_BEFORE; }
+        break;
+      case 265: /* trigger_event ::= DELETE|INSERT */
+      case 266: /* trigger_event ::= UPDATE */ yytestcase(yyruleno==266);
+{yymsp[0].minor.yy28.a = yymsp[0].major; /*A-overwrites-X*/ yymsp[0].minor.yy28.b = 0;}
+        break;
+      case 267: /* trigger_event ::= UPDATE OF idlist */
+{yymsp[-2].minor.yy28.a = TK_UPDATE; yymsp[-2].minor.yy28.b = yymsp[0].minor.yy204;}
+        break;
+      case 268: /* when_clause ::= */
+      case 287: /* key_opt ::= */ yytestcase(yyruleno==287);
+{ yymsp[1].minor.yy590 = 0; }
+        break;
+      case 269: /* when_clause ::= WHEN expr */
+      case 288: /* key_opt ::= KEY expr */ yytestcase(yyruleno==288);
+{ yymsp[-1].minor.yy590 = yymsp[0].minor.yy590; }
+        break;
+      case 270: /* trigger_cmd_list ::= trigger_cmd_list trigger_cmd SEMI */
+{
+  assert( yymsp[-2].minor.yy319!=0 );
+  yymsp[-2].minor.yy319->pLast->pNext = yymsp[-1].minor.yy319;
+  yymsp[-2].minor.yy319->pLast = yymsp[-1].minor.yy319;
+}
+        break;
+      case 271: /* trigger_cmd_list ::= trigger_cmd SEMI */
+{
+  assert( yymsp[-1].minor.yy319!=0 );
+  yymsp[-1].minor.yy319->pLast = yymsp[-1].minor.yy319;
+}
+        break;
+      case 272: /* trnm ::= nm DOT nm */
+{
+  yymsp[-2].minor.yy0 = yymsp[0].minor.yy0;
+  sqlite3ErrorMsg(pParse,
+        "qualified table names are not allowed on INSERT, UPDATE, and DELETE "
+        "statements within triggers");
+}
+        break;
+      case 273: /* tridxby ::= INDEXED BY nm */
+{
+  sqlite3ErrorMsg(pParse,
+        "the INDEXED BY clause is not allowed on UPDATE or DELETE statements "
+        "within triggers");
+}
+        break;
+      case 274: /* tridxby ::= NOT INDEXED */
+{
+  sqlite3ErrorMsg(pParse,
+        "the NOT INDEXED clause is not allowed on UPDATE or DELETE statements "
+        "within triggers");
+}
+        break;
+      case 275: /* trigger_cmd ::= UPDATE orconf trnm tridxby SET setlist from where_opt scanpt */
+{yylhsminor.yy319 = sqlite3TriggerUpdateStep(pParse, &yymsp[-6].minor.yy0, yymsp[-2].minor.yy563, yymsp[-3].minor.yy402, yymsp[-1].minor.yy590, yymsp[-7].minor.yy502, yymsp[-8].minor.yy0.z, yymsp[0].minor.yy342);}
+  yymsp[-8].minor.yy319 = yylhsminor.yy319;
+        break;
+      case 276: /* trigger_cmd ::= scanpt insert_cmd INTO trnm idlist_opt select upsert scanpt */
+{
+   yylhsminor.yy319 = sqlite3TriggerInsertStep(pParse,&yymsp[-4].minor.yy0,yymsp[-3].minor.yy204,yymsp[-2].minor.yy637,yymsp[-6].minor.yy502,yymsp[-1].minor.yy403,yymsp[-7].minor.yy342,yymsp[0].minor.yy342);/*yylhsminor.yy319-overwrites-yymsp[-6].minor.yy502*/
+}
+  yymsp[-7].minor.yy319 = yylhsminor.yy319;
+        break;
+      case 277: /* trigger_cmd ::= DELETE FROM trnm tridxby where_opt scanpt */
+{yylhsminor.yy319 = sqlite3TriggerDeleteStep(pParse, &yymsp[-3].minor.yy0, yymsp[-1].minor.yy590, yymsp[-5].minor.yy0.z, yymsp[0].minor.yy342);}
+  yymsp[-5].minor.yy319 = yylhsminor.yy319;
+        break;
+      case 278: /* trigger_cmd ::= scanpt select scanpt */
+{yylhsminor.yy319 = sqlite3TriggerSelectStep(pParse->db, yymsp[-1].minor.yy637, yymsp[-2].minor.yy342, yymsp[0].minor.yy342); /*yylhsminor.yy319-overwrites-yymsp[-1].minor.yy637*/}
+  yymsp[-2].minor.yy319 = yylhsminor.yy319;
+        break;
+      case 279: /* expr ::= RAISE LP IGNORE RP */
+{
+  yymsp[-3].minor.yy590 = sqlite3PExpr(pParse, TK_RAISE, 0, 0);
+  if( yymsp[-3].minor.yy590 ){
+    yymsp[-3].minor.yy590->affExpr = OE_Ignore;
+  }
+}
+        break;
+      case 280: /* expr ::= RAISE LP raisetype COMMA expr RP */
+{
+  yymsp[-5].minor.yy590 = sqlite3PExpr(pParse, TK_RAISE, yymsp[-1].minor.yy590, 0);
+  if( yymsp[-5].minor.yy590 ) {
+    yymsp[-5].minor.yy590->affExpr = (char)yymsp[-3].minor.yy502;
+  }
+}
+        break;
+      case 281: /* raisetype ::= ROLLBACK */
+{yymsp[0].minor.yy502 = OE_Rollback;}
+        break;
+      case 283: /* raisetype ::= FAIL */
+{yymsp[0].minor.yy502 = OE_Fail;}
+        break;
+      case 284: /* cmd ::= DROP TRIGGER ifexists fullname */
+{
+  sqlite3DropTrigger(pParse,yymsp[0].minor.yy563,yymsp[-1].minor.yy502);
+}
+        break;
+      case 285: /* cmd ::= ATTACH database_kw_opt expr AS expr key_opt */
+{
+  sqlite3Attach(pParse, yymsp[-3].minor.yy590, yymsp[-1].minor.yy590, yymsp[0].minor.yy590);
+}
+        break;
+      case 286: /* cmd ::= DETACH database_kw_opt expr */
+{
+  sqlite3Detach(pParse, yymsp[0].minor.yy590);
+}
+        break;
+      case 289: /* cmd ::= REINDEX */
+{sqlite3Reindex(pParse, 0, 0);}
+        break;
+      case 290: /* cmd ::= REINDEX nm dbnm */
+{sqlite3Reindex(pParse, &yymsp[-1].minor.yy0, &yymsp[0].minor.yy0);}
+        break;
+      case 291: /* cmd ::= ANALYZE */
+{sqlite3Analyze(pParse, 0, 0);}
+        break;
+      case 292: /* cmd ::= ANALYZE nm dbnm */
+{sqlite3Analyze(pParse, &yymsp[-1].minor.yy0, &yymsp[0].minor.yy0);}
+        break;
+      case 293: /* cmd ::= ALTER TABLE fullname RENAME TO nm */
+{
+  sqlite3AlterRenameTable(pParse,yymsp[-3].minor.yy563,&yymsp[0].minor.yy0);
+}
+        break;
+      case 294: /* cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt columnname carglist */
+{
+  yymsp[-1].minor.yy0.n = (int)(pParse->sLastToken.z-yymsp[-1].minor.yy0.z) + pParse->sLastToken.n;
+  sqlite3AlterFinishAddColumn(pParse, &yymsp[-1].minor.yy0);
+}
+        break;
+      case 295: /* cmd ::= ALTER TABLE fullname DROP kwcolumn_opt nm */
+{
+  sqlite3AlterDropColumn(pParse, yymsp[-3].minor.yy563, &yymsp[0].minor.yy0);
+}
+        break;
+      case 296: /* add_column_fullname ::= fullname */
+{
+  disableLookaside(pParse);
+  sqlite3AlterBeginAddColumn(pParse, yymsp[0].minor.yy563);
+}
+        break;
+      case 297: /* cmd ::= ALTER TABLE fullname RENAME kwcolumn_opt nm TO nm */
+{
+  sqlite3AlterRenameColumn(pParse, yymsp[-5].minor.yy563, &yymsp[-2].minor.yy0, &yymsp[0].minor.yy0);
+}
+        break;
+      case 298: /* cmd ::= create_vtab */
+{sqlite3VtabFinishParse(pParse,0);}
+        break;
+      case 299: /* cmd ::= create_vtab LP vtabarglist RP */
+{sqlite3VtabFinishParse(pParse,&yymsp[0].minor.yy0);}
+        break;
+      case 300: /* create_vtab ::= createkw VIRTUAL TABLE ifnotexists nm dbnm USING nm */
+{
+    sqlite3VtabBeginParse(pParse, &yymsp[-3].minor.yy0, &yymsp[-2].minor.yy0, &yymsp[0].minor.yy0, yymsp[-4].minor.yy502);
+}
+        break;
+      case 301: /* vtabarg ::= */
+{sqlite3VtabArgInit(pParse);}
+        break;
+      case 302: /* vtabargtoken ::= ANY */
+      case 303: /* vtabargtoken ::= lp anylist RP */ yytestcase(yyruleno==303);
+      case 304: /* lp ::= LP */ yytestcase(yyruleno==304);
+{sqlite3VtabArgExtend(pParse,&yymsp[0].minor.yy0);}
+        break;
+      case 305: /* with ::= WITH wqlist */
+      case 306: /* with ::= WITH RECURSIVE wqlist */ yytestcase(yyruleno==306);
+{ sqlite3WithPush(pParse, yymsp[0].minor.yy125, 1); }
+        break;
+      case 307: /* wqas ::= AS */
+{yymsp[0].minor.yy444 = M10d_Any;}
+        break;
+      case 308: /* wqas ::= AS MATERIALIZED */
+{yymsp[-1].minor.yy444 = M10d_Yes;}
+        break;
+      case 309: /* wqas ::= AS NOT MATERIALIZED */
+{yymsp[-2].minor.yy444 = M10d_No;}
+        break;
+      case 310: /* wqitem ::= withnm eidlist_opt wqas LP select RP */
+{
+  yymsp[-5].minor.yy361 = sqlite3CteNew(pParse, &yymsp[-5].minor.yy0, yymsp[-4].minor.yy402, yymsp[-1].minor.yy637, yymsp[-3].minor.yy444); /*A-overwrites-X*/
+}
+        break;
+      case 311: /* withnm ::= nm */
+{pParse->bHasWith = 1;}
+        break;
+      case 312: /* wqlist ::= wqitem */
+{
+  yymsp[0].minor.yy125 = sqlite3WithAdd(pParse, 0, yymsp[0].minor.yy361); /*A-overwrites-X*/
+}
+        break;
+      case 313: /* wqlist ::= wqlist COMMA wqitem */
+{
+  yymsp[-2].minor.yy125 = sqlite3WithAdd(pParse, yymsp[-2].minor.yy125, yymsp[0].minor.yy361);
+}
+        break;
+      case 314: /* windowdefn_list ::= windowdefn_list COMMA windowdefn */
+{
+  assert( yymsp[0].minor.yy483!=0 );
+  sqlite3WindowChain(pParse, yymsp[0].minor.yy483, yymsp[-2].minor.yy483);
+  yymsp[0].minor.yy483->pNextWin = yymsp[-2].minor.yy483;
+  yylhsminor.yy483 = yymsp[0].minor.yy483;
+}
+  yymsp[-2].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 315: /* windowdefn ::= nm AS LP window RP */
+{
+  if( ALWAYS(yymsp[-1].minor.yy483) ){
+    yymsp[-1].minor.yy483->zName = sqlite3DbStrNDup(pParse->db, yymsp[-4].minor.yy0.z, yymsp[-4].minor.yy0.n);
+  }
+  yylhsminor.yy483 = yymsp[-1].minor.yy483;
+}
+  yymsp[-4].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 316: /* window ::= PARTITION BY nexprlist orderby_opt frame_opt */
+{
+  yymsp[-4].minor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, yymsp[-2].minor.yy402, yymsp[-1].minor.yy402, 0);
+}
+        break;
+      case 317: /* window ::= nm PARTITION BY nexprlist orderby_opt frame_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, yymsp[-2].minor.yy402, yymsp[-1].minor.yy402, &yymsp[-5].minor.yy0);
+}
+  yymsp[-5].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 318: /* window ::= ORDER BY sortlist frame_opt */
+{
+  yymsp[-3].minor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, 0, yymsp[-1].minor.yy402, 0);
+}
+        break;
+      case 319: /* window ::= nm ORDER BY sortlist frame_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, 0, yymsp[-1].minor.yy402, &yymsp[-4].minor.yy0);
+}
+  yymsp[-4].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 320: /* window ::= nm frame_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAssemble(pParse, yymsp[0].minor.yy483, 0, 0, &yymsp[-1].minor.yy0);
+}
+  yymsp[-1].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 321: /* frame_opt ::= */
+{
+  yymsp[1].minor.yy483 = sqlite3WindowAlloc(pParse, 0, TK_UNBOUNDED, 0, TK_CURRENT, 0, 0);
+}
+        break;
+      case 322: /* frame_opt ::= range_or_rows frame_bound_s frame_exclude_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAlloc(pParse, yymsp[-2].minor.yy502, yymsp[-1].minor.yy205.eType, yymsp[-1].minor.yy205.pExpr, TK_CURRENT, 0, yymsp[0].minor.yy444);
+}
+  yymsp[-2].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 323: /* frame_opt ::= range_or_rows BETWEEN frame_bound_s AND frame_bound_e frame_exclude_opt */
+{
+  yylhsminor.yy483 = sqlite3WindowAlloc(pParse, yymsp[-5].minor.yy502, yymsp[-3].minor.yy205.eType, yymsp[-3].minor.yy205.pExpr, yymsp[-1].minor.yy205.eType, yymsp[-1].minor.yy205.pExpr, yymsp[0].minor.yy444);
+}
+  yymsp[-5].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 325: /* frame_bound_s ::= frame_bound */
+      case 327: /* frame_bound_e ::= frame_bound */ yytestcase(yyruleno==327);
+{yylhsminor.yy205 = yymsp[0].minor.yy205;}
+  yymsp[0].minor.yy205 = yylhsminor.yy205;
+        break;
+      case 326: /* frame_bound_s ::= UNBOUNDED PRECEDING */
+      case 328: /* frame_bound_e ::= UNBOUNDED FOLLOWING */ yytestcase(yyruleno==328);
+      case 330: /* frame_bound ::= CURRENT ROW */ yytestcase(yyruleno==330);
+{yylhsminor.yy205.eType = yymsp[-1].major; yylhsminor.yy205.pExpr = 0;}
+  yymsp[-1].minor.yy205 = yylhsminor.yy205;
+        break;
+      case 329: /* frame_bound ::= expr PRECEDING|FOLLOWING */
+{yylhsminor.yy205.eType = yymsp[0].major; yylhsminor.yy205.pExpr = yymsp[-1].minor.yy590;}
+  yymsp[-1].minor.yy205 = yylhsminor.yy205;
+        break;
+      case 331: /* frame_exclude_opt ::= */
+{yymsp[1].minor.yy444 = 0;}
+        break;
+      case 332: /* frame_exclude_opt ::= EXCLUDE frame_exclude */
+{yymsp[-1].minor.yy444 = yymsp[0].minor.yy444;}
+        break;
+      case 333: /* frame_exclude ::= NO OTHERS */
+      case 334: /* frame_exclude ::= CURRENT ROW */ yytestcase(yyruleno==334);
+{yymsp[-1].minor.yy444 = yymsp[-1].major; /*A-overwrites-X*/}
+        break;
+      case 335: /* frame_exclude ::= GROUP|TIES */
+{yymsp[0].minor.yy444 = yymsp[0].major; /*A-overwrites-X*/}
+        break;
+      case 336: /* window_clause ::= WINDOW windowdefn_list */
+{ yymsp[-1].minor.yy483 = yymsp[0].minor.yy483; }
+        break;
+      case 337: /* filter_over ::= filter_clause over_clause */
+{
+  if( yymsp[0].minor.yy483 ){
+    yymsp[0].minor.yy483->pFilter = yymsp[-1].minor.yy590;
+  }else{
+    sqlite3ExprDelete(pParse->db, yymsp[-1].minor.yy590);
+  }
+  yylhsminor.yy483 = yymsp[0].minor.yy483;
+}
+  yymsp[-1].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 338: /* filter_over ::= over_clause */
+{
+  yylhsminor.yy483 = yymsp[0].minor.yy483;
+}
+  yymsp[0].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 339: /* filter_over ::= filter_clause */
+{
+  yylhsminor.yy483 = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
+  if( yylhsminor.yy483 ){
+    yylhsminor.yy483->eFrmType = TK_FILTER;
+    yylhsminor.yy483->pFilter = yymsp[0].minor.yy590;
+  }else{
+    sqlite3ExprDelete(pParse->db, yymsp[0].minor.yy590);
+  }
+}
+  yymsp[0].minor.yy483 = yylhsminor.yy483;
+        break;
+      case 340: /* over_clause ::= OVER LP window RP */
+{
+  yymsp[-3].minor.yy483 = yymsp[-1].minor.yy483;
+  assert( yymsp[-3].minor.yy483!=0 );
+}
+        break;
+      case 341: /* over_clause ::= OVER nm */
+{
+  yymsp[-1].minor.yy483 = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
+  if( yymsp[-1].minor.yy483 ){
+    yymsp[-1].minor.yy483->zName = sqlite3DbStrNDup(pParse->db, yymsp[0].minor.yy0.z, yymsp[0].minor.yy0.n);
+  }
+}
+        break;
+      case 342: /* filter_clause ::= FILTER LP WHERE expr RP */
+{ yymsp[-4].minor.yy590 = yymsp[-1].minor.yy590; }
+        break;
+      case 343: /* term ::= QNUMBER */
+{
+  yylhsminor.yy590=tokenExpr(pParse,yymsp[0].major,yymsp[0].minor.yy0);
+  sqlite3DequoteNumber(pParse, yylhsminor.yy590);
+}
+  yymsp[0].minor.yy590 = yylhsminor.yy590;
+        break;
+      default:
+      /* (344) input ::= cmdlist */ yytestcase(yyruleno==344);
+      /* (345) cmdlist ::= cmdlist ecmd */ yytestcase(yyruleno==345);
+      /* (346) cmdlist ::= ecmd (OPTIMIZED OUT) */ assert(yyruleno!=346);
+      /* (347) ecmd ::= SEMI */ yytestcase(yyruleno==347);
+      /* (348) ecmd ::= cmdx SEMI */ yytestcase(yyruleno==348);
+      /* (349) ecmd ::= explain cmdx SEMI (NEVER REDUCES) */ assert(yyruleno!=349);
+      /* (350) trans_opt ::= */ yytestcase(yyruleno==350);
+      /* (351) trans_opt ::= TRANSACTION */ yytestcase(yyruleno==351);
+      /* (352) trans_opt ::= TRANSACTION nm */ yytestcase(yyruleno==352);
+      /* (353) savepoint_opt ::= SAVEPOINT */ yytestcase(yyruleno==353);
+      /* (354) savepoint_opt ::= */ yytestcase(yyruleno==354);
+      /* (355) cmd ::= create_table create_table_args */ yytestcase(yyruleno==355);
+      /* (356) table_option_set ::= table_option (OPTIMIZED OUT) */ assert(yyruleno!=356);
+      /* (357) columnlist ::= columnlist COMMA columnname carglist */ yytestcase(yyruleno==357);
+      /* (358) columnlist ::= columnname carglist */ yytestcase(yyruleno==358);
+      /* (359) nm ::= ID|INDEXED|JOIN_KW */ yytestcase(yyruleno==359);
+      /* (360) nm ::= STRING */ yytestcase(yyruleno==360);
+      /* (361) typetoken ::= typename */ yytestcase(yyruleno==361);
+      /* (362) typename ::= ID|STRING */ yytestcase(yyruleno==362);
+      /* (363) signed ::= plus_num (OPTIMIZED OUT) */ assert(yyruleno!=363);
+      /* (364) signed ::= minus_num (OPTIMIZED OUT) */ assert(yyruleno!=364);
+      /* (365) carglist ::= carglist ccons */ yytestcase(yyruleno==365);
+      /* (366) carglist ::= */ yytestcase(yyruleno==366);
+      /* (367) ccons ::= NULL onconf */ yytestcase(yyruleno==367);
+      /* (368) ccons ::= GENERATED ALWAYS AS generated */ yytestcase(yyruleno==368);
+      /* (369) ccons ::= AS generated */ yytestcase(yyruleno==369);
+      /* (370) conslist_opt ::= COMMA conslist */ yytestcase(yyruleno==370);
+      /* (371) conslist ::= conslist tconscomma tcons */ yytestcase(yyruleno==371);
+      /* (372) conslist ::= tcons (OPTIMIZED OUT) */ assert(yyruleno!=372);
+      /* (373) tconscomma ::= */ yytestcase(yyruleno==373);
+      /* (374) defer_subclause_opt ::= defer_subclause (OPTIMIZED OUT) */ assert(yyruleno!=374);
+      /* (375) resolvetype ::= raisetype (OPTIMIZED OUT) */ assert(yyruleno!=375);
+      /* (376) selectnowith ::= oneselect (OPTIMIZED OUT) */ assert(yyruleno!=376);
+      /* (377) oneselect ::= values */ yytestcase(yyruleno==377);
+      /* (378) sclp ::= selcollist COMMA */ yytestcase(yyruleno==378);
+      /* (379) as ::= ID|STRING */ yytestcase(yyruleno==379);
+      /* (380) indexed_opt ::= indexed_by (OPTIMIZED OUT) */ assert(yyruleno!=380);
+      /* (381) returning ::= */ yytestcase(yyruleno==381);
+      /* (382) expr ::= term (OPTIMIZED OUT) */ assert(yyruleno!=382);
+      /* (383) likeop ::= LIKE_KW|MATCH */ yytestcase(yyruleno==383);
+      /* (384) case_operand ::= expr */ yytestcase(yyruleno==384);
+      /* (385) exprlist ::= nexprlist */ yytestcase(yyruleno==385);
+      /* (386) nmnum ::= plus_num (OPTIMIZED OUT) */ assert(yyruleno!=386);
+      /* (387) nmnum ::= nm (OPTIMIZED OUT) */ assert(yyruleno!=387);
+      /* (388) nmnum ::= ON */ yytestcase(yyruleno==388);
+      /* (389) nmnum ::= DELETE */ yytestcase(yyruleno==389);
+      /* (390) nmnum ::= DEFAULT */ yytestcase(yyruleno==390);
+      /* (391) plus_num ::= INTEGER|FLOAT */ yytestcase(yyruleno==391);
+      /* (392) foreach_clause ::= */ yytestcase(yyruleno==392);
+      /* (393) foreach_clause ::= FOR EACH ROW */ yytestcase(yyruleno==393);
+      /* (394) trnm ::= nm */ yytestcase(yyruleno==394);
+      /* (395) tridxby ::= */ yytestcase(yyruleno==395);
+      /* (396) database_kw_opt ::= DATABASE */ yytestcase(yyruleno==396);
+      /* (397) database_kw_opt ::= */ yytestcase(yyruleno==397);
+      /* (398) kwcolumn_opt ::= */ yytestcase(yyruleno==398);
+      /* (399) kwcolumn_opt ::= COLUMNKW */ yytestcase(yyruleno==399);
+      /* (400) vtabarglist ::= vtabarg */ yytestcase(yyruleno==400);
+      /* (401) vtabarglist ::= vtabarglist COMMA vtabarg */ yytestcase(yyruleno==401);
+      /* (402) vtabarg ::= vtabarg vtabargtoken */ yytestcase(yyruleno==402);
+      /* (403) anylist ::= */ yytestcase(yyruleno==403);
+      /* (404) anylist ::= anylist LP anylist RP */ yytestcase(yyruleno==404);
+      /* (405) anylist ::= anylist ANY */ yytestcase(yyruleno==405);
+      /* (406) with ::= */ yytestcase(yyruleno==406);
+      /* (407) windowdefn_list ::= windowdefn (OPTIMIZED OUT) */ assert(yyruleno!=407);
+      /* (408) window ::= frame_opt (OPTIMIZED OUT) */ assert(yyruleno!=408);
+        break;
+/********** End reduce actions ************************************************/
+  };
+  assert( yyruleno<sizeof(yyRuleInfoLhs)/sizeof(yyRuleInfoLhs[0]) );
+  yygoto = yyRuleInfoLhs[yyruleno];
+  yysize = yyRuleInfoNRhs[yyruleno];
+  yyact = yy_find_reduce_action(yymsp[yysize].stateno,(YYCODETYPE)yygoto);
+
+  /* There are no SHIFTREDUCE actions on nonterminals because the table
+  ** generator has simplified them to pure REDUCE actions. */
+  assert( !(yyact>YY_MAX_SHIFT && yyact<=YY_MAX_SHIFTREDUCE) );
+
+  /* It is not possible for a REDUCE to be followed by an error */
+  assert( yyact!=YY_ERROR_ACTION );
+
+  yymsp += yysize+1;
+  yypParser->yytos = yymsp;
+  yymsp->stateno = (YYACTIONTYPE)yyact;
+  yymsp->major = (YYCODETYPE)yygoto;
+  yyTraceShift(yypParser, yyact, "... then shift");
+  return yyact;
+}
+
+/*
+** The following code executes when the parse fails
+*/
+#ifndef YYNOERRORRECOVERY
+static void yy_parse_failed(
+  yyParser *yypParser           /* The parser */
+){
+  sqlite3ParserARG_FETCH
+  sqlite3ParserCTX_FETCH
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sFail!\n",yyTracePrompt);
+  }
+#endif
+  while( yypParser->yytos>yypParser->yystack ) yy_pop_parser_stack(yypParser);
+  /* Here code is inserted which will be executed whenever the
+  ** parser fails */
+/************ Begin %parse_failure code ***************************************/
+/************ End %parse_failure code *****************************************/
+  sqlite3ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3ParserCTX_STORE
+}
+#endif /* YYNOERRORRECOVERY */
+
+/*
+** The following code executes when a syntax error first occurs.
+*/
+static void yy_syntax_error(
+  yyParser *yypParser,           /* The parser */
+  int yymajor,                   /* The major type of the error token */
+  sqlite3ParserTOKENTYPE yyminor         /* The minor type of the error token */
+){
+  sqlite3ParserARG_FETCH
+  sqlite3ParserCTX_FETCH
+#define TOKEN yyminor
+/************ Begin %syntax_error code ****************************************/
+
+  UNUSED_PARAMETER(yymajor);  /* Silence some compiler warnings */
+  if( TOKEN.z[0] ){
+    parserSyntaxError(pParse, &TOKEN);
+  }else{
+    sqlite3ErrorMsg(pParse, "incomplete input");
+  }
+/************ End %syntax_error code ******************************************/
+  sqlite3ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3ParserCTX_STORE
+}
+
+/*
+** The following is executed when the parser accepts
+*/
+static void yy_accept(
+  yyParser *yypParser           /* The parser */
+){
+  sqlite3ParserARG_FETCH
+  sqlite3ParserCTX_FETCH
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    fprintf(yyTraceFILE,"%sAccept!\n",yyTracePrompt);
+  }
+#endif
+#ifndef YYNOERRORRECOVERY
+  yypParser->yyerrcnt = -1;
+#endif
+  assert( yypParser->yytos==yypParser->yystack );
+  /* Here code is inserted which will be executed whenever the
+  ** parser accepts */
+/*********** Begin %parse_accept code *****************************************/
+/*********** End %parse_accept code *******************************************/
+  sqlite3ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3ParserCTX_STORE
+}
+
+/* The main parser program.
+** The first argument is a pointer to a structure obtained from
+** "sqlite3ParserAlloc" which describes the current state of the parser.
+** The second argument is the major token number.  The third is
+** the minor token.  The fourth optional argument is whatever the
+** user wants (and specified in the grammar) and is available for
+** use by the action routines.
+**
+** Inputs:
+** <ul>
+** <li> A pointer to the parser (an opaque structure.)
+** <li> The major token number.
+** <li> The minor token number.
+** <li> An option argument of a grammar-specified type.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+SQLITE_PRIVATE void sqlite3Parser(
+  void *yyp,                   /* The parser */
+  int yymajor,                 /* The major token code number */
+  sqlite3ParserTOKENTYPE yyminor       /* The value for the token */
+  sqlite3ParserARG_PDECL               /* Optional %extra_argument parameter */
+){
+  YYMINORTYPE yyminorunion;
+  YYACTIONTYPE yyact;   /* The parser action. */
+#if !defined(YYERRORSYMBOL) && !defined(YYNOERRORRECOVERY)
+  int yyendofinput;     /* True if we are at the end of input */
+#endif
+#ifdef YYERRORSYMBOL
+  int yyerrorhit = 0;   /* True if yymajor has invoked an error */
+#endif
+  yyParser *yypParser = (yyParser*)yyp;  /* The parser */
+  sqlite3ParserCTX_FETCH
+  sqlite3ParserARG_STORE
+
+  assert( yypParser->yytos!=0 );
+#if !defined(YYERRORSYMBOL) && !defined(YYNOERRORRECOVERY)
+  yyendofinput = (yymajor==0);
+#endif
+
+  yyact = yypParser->yytos->stateno;
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    if( yyact < YY_MIN_REDUCE ){
+      fprintf(yyTraceFILE,"%sInput '%s' in state %d\n",
+              yyTracePrompt,yyTokenName[yymajor],yyact);
+    }else{
+      fprintf(yyTraceFILE,"%sInput '%s' with pending reduce %d\n",
+              yyTracePrompt,yyTokenName[yymajor],yyact-YY_MIN_REDUCE);
+    }
+  }
+#endif
+
+  while(1){ /* Exit by "break" */
+    assert( yypParser->yytos>=yypParser->yystack );
+    assert( yyact==yypParser->yytos->stateno );
+    yyact = yy_find_shift_action((YYCODETYPE)yymajor,yyact);
+    if( yyact >= YY_MIN_REDUCE ){
+      unsigned int yyruleno = yyact - YY_MIN_REDUCE; /* Reduce by this rule */
+#ifndef NDEBUG
+      assert( yyruleno<(int)(sizeof(yyRuleName)/sizeof(yyRuleName[0])) );
+      if( yyTraceFILE ){
+        int yysize = yyRuleInfoNRhs[yyruleno];
+        if( yysize ){
+          fprintf(yyTraceFILE, "%sReduce %d [%s]%s, pop back to state %d.\n",
+            yyTracePrompt,
+            yyruleno, yyRuleName[yyruleno],
+            yyruleno<YYNRULE_WITH_ACTION ? "" : " without external action",
+            yypParser->yytos[yysize].stateno);
+        }else{
+          fprintf(yyTraceFILE, "%sReduce %d [%s]%s.\n",
+            yyTracePrompt, yyruleno, yyRuleName[yyruleno],
+            yyruleno<YYNRULE_WITH_ACTION ? "" : " without external action");
+        }
+      }
+#endif /* NDEBUG */
+
+      /* Check that the stack is large enough to grow by a single entry
+      ** if the RHS of the rule is empty.  This ensures that there is room
+      ** enough on the stack to push the LHS value */
+      if( yyRuleInfoNRhs[yyruleno]==0 ){
+#ifdef YYTRACKMAXSTACKDEPTH
+        if( (int)(yypParser->yytos - yypParser->yystack)>yypParser->yyhwm ){
+          yypParser->yyhwm++;
+          assert( yypParser->yyhwm ==
+                  (int)(yypParser->yytos - yypParser->yystack));
+        }
+#endif
+        if( yypParser->yytos>=yypParser->yystackEnd ){
+          if( yyGrowStack(yypParser) ){
+            yyStackOverflow(yypParser);
+            break;
+          }
+        }
+      }
+      yyact = yy_reduce(yypParser,yyruleno,yymajor,yyminor sqlite3ParserCTX_PARAM);
+    }else if( yyact <= YY_MAX_SHIFTREDUCE ){
+      yy_shift(yypParser,yyact,(YYCODETYPE)yymajor,yyminor);
+#ifndef YYNOERRORRECOVERY
+      yypParser->yyerrcnt--;
+#endif
+      break;
+    }else if( yyact==YY_ACCEPT_ACTION ){
+      yypParser->yytos--;
+      yy_accept(yypParser);
+      return;
+    }else{
+      assert( yyact == YY_ERROR_ACTION );
+      yyminorunion.yy0 = yyminor;
+#ifdef YYERRORSYMBOL
+      int yymx;
+#endif
+#ifndef NDEBUG
+      if( yyTraceFILE ){
+        fprintf(yyTraceFILE,"%sSyntax Error!\n",yyTracePrompt);
+      }
+#endif
+#ifdef YYERRORSYMBOL
+      /* A syntax error has occurred.
+      ** The response to an error depends upon whether or not the
+      ** grammar defines an error token "ERROR".
+      **
+      ** This is what we do if the grammar does define ERROR:
+      **
+      **  * Call the %syntax_error function.
+      **
+      **  * Begin popping the stack until we enter a state where
+      **    it is legal to shift the error symbol, then shift
+      **    the error symbol.
+      **
+      **  * Set the error count to three.
+      **
+      **  * Begin accepting and shifting new tokens.  No new error
+      **    processing will occur until three tokens have been
+      **    shifted successfully.
+      **
+      */
+      if( yypParser->yyerrcnt<0 ){
+        yy_syntax_error(yypParser,yymajor,yyminor);
+      }
+      yymx = yypParser->yytos->major;
+      if( yymx==YYERRORSYMBOL || yyerrorhit ){
+#ifndef NDEBUG
+        if( yyTraceFILE ){
+          fprintf(yyTraceFILE,"%sDiscard input token %s\n",
+             yyTracePrompt,yyTokenName[yymajor]);
+        }
+#endif
+        yy_destructor(yypParser, (YYCODETYPE)yymajor, &yyminorunion);
+        yymajor = YYNOCODE;
+      }else{
+        while( yypParser->yytos > yypParser->yystack ){
+          yyact = yy_find_reduce_action(yypParser->yytos->stateno,
+                                        YYERRORSYMBOL);
+          if( yyact<=YY_MAX_SHIFTREDUCE ) break;
+          yy_pop_parser_stack(yypParser);
+        }
+        if( yypParser->yytos <= yypParser->yystack || yymajor==0 ){
+          yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+          yy_parse_failed(yypParser);
+#ifndef YYNOERRORRECOVERY
+          yypParser->yyerrcnt = -1;
+#endif
+          yymajor = YYNOCODE;
+        }else if( yymx!=YYERRORSYMBOL ){
+          yy_shift(yypParser,yyact,YYERRORSYMBOL,yyminor);
+        }
+      }
+      yypParser->yyerrcnt = 3;
+      yyerrorhit = 1;
+      if( yymajor==YYNOCODE ) break;
+      yyact = yypParser->yytos->stateno;
+#elif defined(YYNOERRORRECOVERY)
+      /* If the YYNOERRORRECOVERY macro is defined, then do not attempt to
+      ** do any kind of error recovery.  Instead, simply invoke the syntax
+      ** error routine and continue going as if nothing had happened.
+      **
+      ** Applications can set this macro (for example inside %include) if
+      ** they intend to abandon the parse upon the first syntax error seen.
+      */
+      yy_syntax_error(yypParser,yymajor, yyminor);
+      yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+      break;
+#else  /* YYERRORSYMBOL is not defined */
+      /* This is what we do if the grammar does not define ERROR:
+      **
+      **  * Report an error message, and throw away the input token.
+      **
+      **  * If the input token is $, then fail the parse.
+      **
+      ** As before, subsequent error messages are suppressed until
+      ** three input tokens have been successfully shifted.
+      */
+      if( yypParser->yyerrcnt<=0 ){
+        yy_syntax_error(yypParser,yymajor, yyminor);
+      }
+      yypParser->yyerrcnt = 3;
+      yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+      if( yyendofinput ){
+        yy_parse_failed(yypParser);
+#ifndef YYNOERRORRECOVERY
+        yypParser->yyerrcnt = -1;
+#endif
+      }
+      break;
+#endif
+    }
+  }
+#ifndef NDEBUG
+  if( yyTraceFILE ){
+    yyStackEntry *i;
+    char cDiv = '[';
+    fprintf(yyTraceFILE,"%sReturn. Stack=",yyTracePrompt);
+    for(i=&yypParser->yystack[1]; i<=yypParser->yytos; i++){
+      fprintf(yyTraceFILE,"%c%s", cDiv, yyTokenName[i->major]);
+      cDiv = ' ';
+    }
+    fprintf(yyTraceFILE,"]\n");
+  }
+#endif
+  return;
+}
+
+/*
+** Return the fallback token corresponding to canonical token iToken, or
+** 0 if iToken has no fallback.
+*/
+SQLITE_PRIVATE int sqlite3ParserFallback(int iToken){
+#ifdef YYFALLBACK
+  assert( iToken<(int)(sizeof(yyFallback)/sizeof(yyFallback[0])) );
+  return yyFallback[iToken];
+#else
+  (void)iToken;
+  return 0;
+#endif
+}
+
+/************** End of parse.c ***********************************************/
+/************** Begin file tokenize.c ****************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** An tokenizer for SQL
+**
+** This file contains C code that splits an SQL input string up into
+** individual tokens and sends those tokens one-by-one over to the
+** parser for analysis.
+*/
+/* #include "sqliteInt.h" */
+/* #include <stdlib.h> */
+
+/* Character classes for tokenizing
+**
+** In the sqlite3GetToken() function, a switch() on aiClass[c] is implemented
+** using a lookup table, whereas a switch() directly on c uses a binary search.
+** The lookup table is much faster.  To maximize speed, and to ensure that
+** a lookup table is used, all of the classes need to be small integers and
+** all of them need to be used within the switch.
+*/
+#define CC_X          0    /* The letter 'x', or start of BLOB literal */
+#define CC_KYWD0      1    /* First letter of a keyword */
+#define CC_KYWD       2    /* Alphabetics or '_'.  Usable in a keyword */
+#define CC_DIGIT      3    /* Digits */
+#define CC_DOLLAR     4    /* '$' */
+#define CC_VARALPHA   5    /* '@', '#', ':'.  Alphabetic SQL variables */
+#define CC_VARNUM     6    /* '?'.  Numeric SQL variables */
+#define CC_SPACE      7    /* Space characters */
+#define CC_QUOTE      8    /* '"', '\'', or '`'.  String literals, quoted ids */
+#define CC_QUOTE2     9    /* '['.   [...] style quoted ids */
+#define CC_PIPE      10    /* '|'.   Bitwise OR or concatenate */
+#define CC_MINUS     11    /* '-'.  Minus or SQL-style comment */
+#define CC_LT        12    /* '<'.  Part of < or <= or <> */
+#define CC_GT        13    /* '>'.  Part of > or >= */
+#define CC_EQ        14    /* '='.  Part of = or == */
+#define CC_BANG      15    /* '!'.  Part of != */
+#define CC_SLASH     16    /* '/'.  / or c-style comment */
+#define CC_LP        17    /* '(' */
+#define CC_RP        18    /* ')' */
+#define CC_SEMI      19    /* ';' */
+#define CC_PLUS      20    /* '+' */
+#define CC_STAR      21    /* '*' */
+#define CC_PERCENT   22    /* '%' */
+#define CC_COMMA     23    /* ',' */
+#define CC_AND       24    /* '&' */
+#define CC_TILDA     25    /* '~' */
+#define CC_DOT       26    /* '.' */
+#define CC_ID        27    /* unicode characters usable in IDs */
+#define CC_ILLEGAL   28    /* Illegal character */
+#define CC_NUL       29    /* 0x00 */
+#define CC_BOM       30    /* First byte of UTF8 BOM:  0xEF 0xBB 0xBF */
+
+static const unsigned char aiClass[] = {
+#ifdef SQLITE_ASCII
+/*         x0  x1  x2  x3  x4  x5  x6  x7  x8  x9  xa  xb  xc  xd  xe  xf */
+/* 0x */   29, 28, 28, 28, 28, 28, 28, 28, 28,  7,  7, 28,  7,  7, 28, 28,
+/* 1x */   28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+/* 2x */    7, 15,  8,  5,  4, 22, 24,  8, 17, 18, 21, 20, 23, 11, 26, 16,
+/* 3x */    3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  5, 19, 12, 14, 13,  6,
+/* 4x */    5,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+/* 5x */    1,  1,  1,  1,  1,  1,  1,  1,  0,  2,  2,  9, 28, 28, 28,  2,
+/* 6x */    8,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+/* 7x */    1,  1,  1,  1,  1,  1,  1,  1,  0,  2,  2, 28, 10, 28, 25, 28,
+/* 8x */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* 9x */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Ax */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Bx */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Cx */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Dx */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+/* Ex */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 30,
+/* Fx */   27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27
+#endif
+#ifdef SQLITE_EBCDIC
+/*         x0  x1  x2  x3  x4  x5  x6  x7  x8  x9  xa  xb  xc  xd  xe  xf */
+/* 0x */   29, 28, 28, 28, 28,  7, 28, 28, 28, 28, 28, 28,  7,  7, 28, 28,
+/* 1x */   28, 28, 28, 28, 28,  7, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+/* 2x */   28, 28, 28, 28, 28,  7, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+/* 3x */   28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+/* 4x */    7, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 26, 12, 17, 20, 10,
+/* 5x */   24, 28, 28, 28, 28, 28, 28, 28, 28, 28, 15,  4, 21, 18, 19, 28,
+/* 6x */   11, 16, 28, 28, 28, 28, 28, 28, 28, 28, 28, 23, 22,  2, 13,  6,
+/* 7x */   28, 28, 28, 28, 28, 28, 28, 28, 28,  8,  5,  5,  5,  8, 14,  8,
+/* 8x */   28,  1,  1,  1,  1,  1,  1,  1,  1,  1, 28, 28, 28, 28, 28, 28,
+/* 9x */   28,  1,  1,  1,  1,  1,  1,  1,  1,  1, 28, 28, 28, 28, 28, 28,
+/* Ax */   28, 25,  1,  1,  1,  1,  1,  0,  2,  2, 28, 28, 28, 28, 28, 28,
+/* Bx */   28, 28, 28, 28, 28, 28, 28, 28, 28, 28,  9, 28, 28, 28, 28, 28,
+/* Cx */   28,  1,  1,  1,  1,  1,  1,  1,  1,  1, 28, 28, 28, 28, 28, 28,
+/* Dx */   28,  1,  1,  1,  1,  1,  1,  1,  1,  1, 28, 28, 28, 28, 28, 28,
+/* Ex */   28, 28,  1,  1,  1,  1,  1,  0,  2,  2, 28, 28, 28, 28, 28, 28,
+/* Fx */    3,  3,  3,  3,  3,  3,  3,  3,  3,  3, 28, 28, 28, 28, 28, 28,
+#endif
+};
+
+/*
+** The charMap() macro maps alphabetic characters (only) into their
+** lower-case ASCII equivalent.  On ASCII machines, this is just
+** an upper-to-lower case map.  On EBCDIC machines we also need
+** to adjust the encoding.  The mapping is only valid for alphabetics
+** which are the only characters for which this feature is used.
+**
+** Used by keywordhash.h
+*/
+#ifdef SQLITE_ASCII
+# define charMap(X) sqlite3UpperToLower[(unsigned char)X]
+#endif
+#ifdef SQLITE_EBCDIC
+# define charMap(X) ebcdicToAscii[(unsigned char)X]
+const unsigned char ebcdicToAscii[] = {
+/* 0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 0x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 1x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 2x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 3x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 4x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 5x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 95,  0,  0,  /* 6x */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* 7x */
+   0, 97, 98, 99,100,101,102,103,104,105,  0,  0,  0,  0,  0,  0,  /* 8x */
+   0,106,107,108,109,110,111,112,113,114,  0,  0,  0,  0,  0,  0,  /* 9x */
+   0,  0,115,116,117,118,119,120,121,122,  0,  0,  0,  0,  0,  0,  /* Ax */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* Bx */
+   0, 97, 98, 99,100,101,102,103,104,105,  0,  0,  0,  0,  0,  0,  /* Cx */
+   0,106,107,108,109,110,111,112,113,114,  0,  0,  0,  0,  0,  0,  /* Dx */
+   0,  0,115,116,117,118,119,120,121,122,  0,  0,  0,  0,  0,  0,  /* Ex */
+   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  /* Fx */
+};
+#endif
+
+/*
+** The sqlite3KeywordCode function looks up an identifier to determine if
+** it is a keyword.  If it is a keyword, the token code of that keyword is
+** returned.  If the input is not a keyword, TK_ID is returned.
+**
+** The implementation of this routine was generated by a program,
+** mkkeywordhash.c, located in the tool subdirectory of the distribution.
+** The output of the mkkeywordhash.c program is written into a file
+** named keywordhash.h and then included into this source file by
+** the #include below.
+*/
+/************** Include keywordhash.h in the middle of tokenize.c ************/
+/************** Begin file keywordhash.h *************************************/
+/***** This file contains automatically generated code ******
+**
+** The code in this file has been automatically generated by
+**
+**   sqlite/tool/mkkeywordhash.c
+**
+** The code in this file implements a function that determines whether
+** or not a given identifier is really an SQL keyword.  The same thing
+** might be implemented more directly using a hand-written hash table.
+** But by using this automatically generated code, the size of the code
+** is substantially reduced.  This is important for embedded applications
+** on platforms with limited memory.
+*/
+/* Hash score: 231 */
+/* zKWText[] encodes 1007 bytes of keyword text in 667 bytes */
+/*   REINDEXEDESCAPEACHECKEYBEFOREIGNOREGEXPLAINSTEADDATABASELECT       */
+/*   ABLEFTHENDEFERRABLELSEXCLUDELETEMPORARYISNULLSAVEPOINTERSECT       */
+/*   IESNOTNULLIKEXCEPTRANSACTIONATURALTERAISEXCLUSIVEXISTS             */
+/*   CONSTRAINTOFFSETRIGGERANGENERATEDETACHAVINGLOBEGINNEREFERENCES     */
+/*   UNIQUERYWITHOUTERELEASEATTACHBETWEENOTHINGROUPSCASCADEFAULT        */
+/*   CASECOLLATECREATECURRENT_DATEIMMEDIATEJOINSERTMATCHPLANALYZE       */
+/*   PRAGMATERIALIZEDEFERREDISTINCTUPDATEVALUESVIRTUALWAYSWHENWHERE     */
+/*   CURSIVEABORTAFTERENAMEANDROPARTITIONAUTOINCREMENTCASTCOLUMN        */
+/*   COMMITCONFLICTCROSSCURRENT_TIMESTAMPRECEDINGFAILASTFILTER          */
+/*   EPLACEFIRSTFOLLOWINGFROMFULLIMITIFORDERESTRICTOTHERSOVER           */
+/*   ETURNINGRIGHTROLLBACKROWSUNBOUNDEDUNIONUSINGVACUUMVIEWINDOWBY      */
+/*   INITIALLYPRIMARY                                                   */
+static const char zKWText[666] = {
+  'R','E','I','N','D','E','X','E','D','E','S','C','A','P','E','A','C','H',
+  'E','C','K','E','Y','B','E','F','O','R','E','I','G','N','O','R','E','G',
+  'E','X','P','L','A','I','N','S','T','E','A','D','D','A','T','A','B','A',
+  'S','E','L','E','C','T','A','B','L','E','F','T','H','E','N','D','E','F',
+  'E','R','R','A','B','L','E','L','S','E','X','C','L','U','D','E','L','E',
+  'T','E','M','P','O','R','A','R','Y','I','S','N','U','L','L','S','A','V',
+  'E','P','O','I','N','T','E','R','S','E','C','T','I','E','S','N','O','T',
+  'N','U','L','L','I','K','E','X','C','E','P','T','R','A','N','S','A','C',
+  'T','I','O','N','A','T','U','R','A','L','T','E','R','A','I','S','E','X',
+  'C','L','U','S','I','V','E','X','I','S','T','S','C','O','N','S','T','R',
+  'A','I','N','T','O','F','F','S','E','T','R','I','G','G','E','R','A','N',
+  'G','E','N','E','R','A','T','E','D','E','T','A','C','H','A','V','I','N',
+  'G','L','O','B','E','G','I','N','N','E','R','E','F','E','R','E','N','C',
+  'E','S','U','N','I','Q','U','E','R','Y','W','I','T','H','O','U','T','E',
+  'R','E','L','E','A','S','E','A','T','T','A','C','H','B','E','T','W','E',
+  'E','N','O','T','H','I','N','G','R','O','U','P','S','C','A','S','C','A',
+  'D','E','F','A','U','L','T','C','A','S','E','C','O','L','L','A','T','E',
+  'C','R','E','A','T','E','C','U','R','R','E','N','T','_','D','A','T','E',
+  'I','M','M','E','D','I','A','T','E','J','O','I','N','S','E','R','T','M',
+  'A','T','C','H','P','L','A','N','A','L','Y','Z','E','P','R','A','G','M',
+  'A','T','E','R','I','A','L','I','Z','E','D','E','F','E','R','R','E','D',
+  'I','S','T','I','N','C','T','U','P','D','A','T','E','V','A','L','U','E',
+  'S','V','I','R','T','U','A','L','W','A','Y','S','W','H','E','N','W','H',
+  'E','R','E','C','U','R','S','I','V','E','A','B','O','R','T','A','F','T',
+  'E','R','E','N','A','M','E','A','N','D','R','O','P','A','R','T','I','T',
+  'I','O','N','A','U','T','O','I','N','C','R','E','M','E','N','T','C','A',
+  'S','T','C','O','L','U','M','N','C','O','M','M','I','T','C','O','N','F',
+  'L','I','C','T','C','R','O','S','S','C','U','R','R','E','N','T','_','T',
+  'I','M','E','S','T','A','M','P','R','E','C','E','D','I','N','G','F','A',
+  'I','L','A','S','T','F','I','L','T','E','R','E','P','L','A','C','E','F',
+  'I','R','S','T','F','O','L','L','O','W','I','N','G','F','R','O','M','F',
+  'U','L','L','I','M','I','T','I','F','O','R','D','E','R','E','S','T','R',
+  'I','C','T','O','T','H','E','R','S','O','V','E','R','E','T','U','R','N',
+  'I','N','G','R','I','G','H','T','R','O','L','L','B','A','C','K','R','O',
+  'W','S','U','N','B','O','U','N','D','E','D','U','N','I','O','N','U','S',
+  'I','N','G','V','A','C','U','U','M','V','I','E','W','I','N','D','O','W',
+  'B','Y','I','N','I','T','I','A','L','L','Y','P','R','I','M','A','R','Y',
+};
+/* aKWHash[i] is the hash value for the i-th keyword */
+static const unsigned char aKWHash[127] = {
+    84,  92, 134,  82, 105,  29,   0,   0,  94,   0,  85,  72,   0,
+    53,  35,  86,  15,   0,  42,  97,  54,  89, 135,  19,   0,   0,
+   140,   0,  40, 129,   0,  22, 107,   0,   9,   0,   0, 123,  80,
+     0,  78,   6,   0,  65, 103, 147,   0, 136, 115,   0,   0,  48,
+     0,  90,  24,   0,  17,   0,  27,  70,  23,  26,   5,  60, 142,
+   110, 122,   0,  73,  91,  71, 145,  61, 120,  74,   0,  49,   0,
+    11,  41,   0, 113,   0,   0,   0, 109,  10, 111, 116, 125,  14,
+    50, 124,   0, 100,   0,  18, 121, 144,  56, 130, 139,  88,  83,
+    37,  30, 126,   0,   0, 108,  51, 131, 128,   0,  34,   0,   0,
+   132,   0,  98,  38,  39,   0,  20,  45, 117,  93,
+};
+/* aKWNext[] forms the hash collision chain.  If aKWHash[i]==0
+** then the i-th keyword has no more hash collisions.  Otherwise,
+** the next keyword with the same hash is aKWHash[i]-1. */
+static const unsigned char aKWNext[148] = {0,
+     0,   0,   0,   0,   4,   0,  43,   0,   0, 106, 114,   0,   0,
+     0,   2,   0,   0, 143,   0,   0,   0,  13,   0,   0,   0,   0,
+   141,   0,   0, 119,  52,   0,   0, 137,  12,   0,   0,  62,   0,
+   138,   0, 133,   0,   0,  36,   0,   0,  28,  77,   0,   0,   0,
+     0,  59,   0,  47,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+     0,  69,   0,   0,   0,   0,   0, 146,   3,   0,  58,   0,   1,
+    75,   0,   0,   0,  31,   0,   0,   0,   0,   0, 127,   0, 104,
+     0,  64,  66,  63,   0,   0,   0,   0,   0,  46,   0,  16,   8,
+     0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  81, 101,   0,
+   112,  21,   7,  67,   0,  79,  96, 118,   0,   0,  68,   0,   0,
+    99,  44,   0,  55,   0,  76,   0,  95,  32,  33,  57,  25,   0,
+   102,   0,   0,  87,
+};
+/* aKWLen[i] is the length (in bytes) of the i-th keyword */
+static const unsigned char aKWLen[148] = {0,
+     7,   7,   5,   4,   6,   4,   5,   3,   6,   7,   3,   6,   6,
+     7,   7,   3,   8,   2,   6,   5,   4,   4,   3,  10,   4,   7,
+     6,   9,   4,   2,   6,   5,   9,   9,   4,   7,   3,   2,   4,
+     4,   6,  11,   6,   2,   7,   5,   5,   9,   6,  10,   4,   6,
+     2,   3,   7,   5,   9,   6,   6,   4,   5,   5,  10,   6,   5,
+     7,   4,   5,   7,   6,   7,   7,   6,   5,   7,   3,   7,   4,
+     7,   6,  12,   9,   4,   6,   5,   4,   7,   6,  12,   8,   8,
+     2,   6,   6,   7,   6,   4,   5,   9,   5,   5,   6,   3,   4,
+     9,  13,   2,   2,   4,   6,   6,   8,   5,  17,  12,   7,   9,
+     4,   4,   6,   7,   5,   9,   4,   4,   5,   2,   5,   8,   6,
+     4,   9,   5,   8,   4,   3,   9,   5,   5,   6,   4,   6,   2,
+     2,   9,   3,   7,
+};
+/* aKWOffset[i] is the index into zKWText[] of the start of
+** the text for the i-th keyword. */
+static const unsigned short int aKWOffset[148] = {0,
+     0,   2,   2,   8,   9,  14,  16,  20,  23,  25,  25,  29,  33,
+    36,  41,  46,  48,  53,  54,  59,  62,  65,  67,  69,  78,  81,
+    86,  90,  90,  94,  99, 101, 105, 111, 119, 123, 123, 123, 126,
+   129, 132, 137, 142, 146, 147, 152, 156, 160, 168, 174, 181, 184,
+   184, 187, 189, 195, 198, 206, 211, 216, 219, 222, 226, 236, 239,
+   244, 244, 248, 252, 259, 265, 271, 277, 277, 283, 284, 288, 295,
+   299, 306, 312, 324, 333, 335, 341, 346, 348, 355, 359, 370, 377,
+   378, 385, 391, 397, 402, 408, 412, 415, 424, 429, 433, 439, 441,
+   444, 453, 455, 457, 466, 470, 476, 482, 490, 495, 495, 495, 511,
+   520, 523, 527, 532, 539, 544, 553, 557, 560, 565, 567, 571, 579,
+   585, 588, 597, 602, 610, 610, 614, 623, 628, 633, 639, 642, 645,
+   648, 650, 655, 659,
+};
+/* aKWCode[i] is the parser symbol code for the i-th keyword */
+static const unsigned char aKWCode[148] = {0,
+  TK_REINDEX,    TK_INDEXED,    TK_INDEX,      TK_DESC,       TK_ESCAPE,
+  TK_EACH,       TK_CHECK,      TK_KEY,        TK_BEFORE,     TK_FOREIGN,
+  TK_FOR,        TK_IGNORE,     TK_LIKE_KW,    TK_EXPLAIN,    TK_INSTEAD,
+  TK_ADD,        TK_DATABASE,   TK_AS,         TK_SELECT,     TK_TABLE,
+  TK_JOIN_KW,    TK_THEN,       TK_END,        TK_DEFERRABLE, TK_ELSE,
+  TK_EXCLUDE,    TK_DELETE,     TK_TEMP,       TK_TEMP,       TK_OR,
+  TK_ISNULL,     TK_NULLS,      TK_SAVEPOINT,  TK_INTERSECT,  TK_TIES,
+  TK_NOTNULL,    TK_NOT,        TK_NO,         TK_NULL,       TK_LIKE_KW,
+  TK_EXCEPT,     TK_TRANSACTION,TK_ACTION,     TK_ON,         TK_JOIN_KW,
+  TK_ALTER,      TK_RAISE,      TK_EXCLUSIVE,  TK_EXISTS,     TK_CONSTRAINT,
+  TK_INTO,       TK_OFFSET,     TK_OF,         TK_SET,        TK_TRIGGER,
+  TK_RANGE,      TK_GENERATED,  TK_DETACH,     TK_HAVING,     TK_LIKE_KW,
+  TK_BEGIN,      TK_JOIN_KW,    TK_REFERENCES, TK_UNIQUE,     TK_QUERY,
+  TK_WITHOUT,    TK_WITH,       TK_JOIN_KW,    TK_RELEASE,    TK_ATTACH,
+  TK_BETWEEN,    TK_NOTHING,    TK_GROUPS,     TK_GROUP,      TK_CASCADE,
+  TK_ASC,        TK_DEFAULT,    TK_CASE,       TK_COLLATE,    TK_CREATE,
+  TK_CTIME_KW,   TK_IMMEDIATE,  TK_JOIN,       TK_INSERT,     TK_MATCH,
+  TK_PLAN,       TK_ANALYZE,    TK_PRAGMA,     TK_MATERIALIZED, TK_DEFERRED,
+  TK_DISTINCT,   TK_IS,         TK_UPDATE,     TK_VALUES,     TK_VIRTUAL,
+  TK_ALWAYS,     TK_WHEN,       TK_WHERE,      TK_RECURSIVE,  TK_ABORT,
+  TK_AFTER,      TK_RENAME,     TK_AND,        TK_DROP,       TK_PARTITION,
+  TK_AUTOINCR,   TK_TO,         TK_IN,         TK_CAST,       TK_COLUMNKW,
+  TK_COMMIT,     TK_CONFLICT,   TK_JOIN_KW,    TK_CTIME_KW,   TK_CTIME_KW,
+  TK_CURRENT,    TK_PRECEDING,  TK_FAIL,       TK_LAST,       TK_FILTER,
+  TK_REPLACE,    TK_FIRST,      TK_FOLLOWING,  TK_FROM,       TK_JOIN_KW,
+  TK_LIMIT,      TK_IF,         TK_ORDER,      TK_RESTRICT,   TK_OTHERS,
+  TK_OVER,       TK_RETURNING,  TK_JOIN_KW,    TK_ROLLBACK,   TK_ROWS,
+  TK_ROW,        TK_UNBOUNDED,  TK_UNION,      TK_USING,      TK_VACUUM,
+  TK_VIEW,       TK_WINDOW,     TK_DO,         TK_BY,         TK_INITIALLY,
+  TK_ALL,        TK_PRIMARY,
+};
+/* Hash table decoded:
+**   0: INSERT
+**   1: IS
+**   2: ROLLBACK TRIGGER
+**   3: IMMEDIATE
+**   4: PARTITION
+**   5: TEMP
+**   6:
+**   7:
+**   8: VALUES WITHOUT
+**   9:
+**  10: MATCH
+**  11: NOTHING
+**  12:
+**  13: OF
+**  14: TIES IGNORE
+**  15: PLAN
+**  16: INSTEAD INDEXED
+**  17:
+**  18: TRANSACTION RIGHT
+**  19: WHEN
+**  20: SET HAVING
+**  21: MATERIALIZED IF
+**  22: ROWS
+**  23: SELECT
+**  24:
+**  25:
+**  26: VACUUM SAVEPOINT
+**  27:
+**  28: LIKE UNION VIRTUAL REFERENCES
+**  29: RESTRICT
+**  30:
+**  31: THEN REGEXP
+**  32: TO
+**  33:
+**  34: BEFORE
+**  35:
+**  36:
+**  37: FOLLOWING COLLATE CASCADE
+**  38: CREATE
+**  39:
+**  40: CASE REINDEX
+**  41: EACH
+**  42:
+**  43: QUERY
+**  44: AND ADD
+**  45: PRIMARY ANALYZE
+**  46:
+**  47: ROW ASC DETACH
+**  48: CURRENT_TIME CURRENT_DATE
+**  49:
+**  50:
+**  51: EXCLUSIVE TEMPORARY
+**  52:
+**  53: DEFERRED
+**  54: DEFERRABLE
+**  55:
+**  56: DATABASE
+**  57:
+**  58: DELETE VIEW GENERATED
+**  59: ATTACH
+**  60: END
+**  61: EXCLUDE
+**  62: ESCAPE DESC
+**  63: GLOB
+**  64: WINDOW ELSE
+**  65: COLUMN
+**  66: FIRST
+**  67:
+**  68: GROUPS ALL
+**  69: DISTINCT DROP KEY
+**  70: BETWEEN
+**  71: INITIALLY
+**  72: BEGIN
+**  73: FILTER CHECK ACTION
+**  74: GROUP INDEX
+**  75:
+**  76: EXISTS DEFAULT
+**  77:
+**  78: FOR CURRENT_TIMESTAMP
+**  79: EXCEPT
+**  80:
+**  81: CROSS
+**  82:
+**  83:
+**  84:
+**  85: CAST
+**  86: FOREIGN AUTOINCREMENT
+**  87: COMMIT
+**  88: CURRENT AFTER ALTER
+**  89: FULL FAIL CONFLICT
+**  90: EXPLAIN
+**  91: CONSTRAINT
+**  92: FROM ALWAYS
+**  93:
+**  94: ABORT
+**  95:
+**  96: AS DO
+**  97: REPLACE WITH RELEASE
+**  98: BY RENAME
+**  99: RANGE RAISE
+** 100: OTHERS
+** 101: USING NULLS
+** 102: PRAGMA
+** 103: JOIN ISNULL OFFSET
+** 104: NOT
+** 105: OR LAST LEFT
+** 106: LIMIT
+** 107:
+** 108:
+** 109: IN
+** 110: INTO
+** 111: OVER RECURSIVE
+** 112: ORDER OUTER
+** 113:
+** 114: INTERSECT UNBOUNDED
+** 115:
+** 116:
+** 117: RETURNING ON
+** 118:
+** 119: WHERE
+** 120: NO INNER
+** 121: NULL
+** 122:
+** 123: TABLE
+** 124: NATURAL NOTNULL
+** 125: PRECEDING
+** 126: UPDATE UNIQUE
+*/
+/* Check to see if z[0..n-1] is a keyword. If it is, write the
+** parser symbol code for that keyword into *pType.  Always
+** return the integer n (the length of the token). */
+static int keywordCode(const char *z, int n, int *pType){
+  int i, j;
+  const char *zKW;
+  assert( n>=2 );
+  i = ((charMap(z[0])*4) ^ (charMap(z[n-1])*3) ^ n*1) % 127;
+  for(i=(int)aKWHash[i]; i>0; i=aKWNext[i]){
+    if( aKWLen[i]!=n ) continue;
+    zKW = &zKWText[aKWOffset[i]];
+#ifdef SQLITE_ASCII
+    if( (z[0]&~0x20)!=zKW[0] ) continue;
+    if( (z[1]&~0x20)!=zKW[1] ) continue;
+    j = 2;
+    while( j<n && (z[j]&~0x20)==zKW[j] ){ j++; }
+#endif
+#ifdef SQLITE_EBCDIC
+    if( toupper(z[0])!=zKW[0] ) continue;
+    if( toupper(z[1])!=zKW[1] ) continue;
+    j = 2;
+    while( j<n && toupper(z[j])==zKW[j] ){ j++; }
+#endif
+    if( j<n ) continue;
+    testcase( i==1 ); /* REINDEX */
+    testcase( i==2 ); /* INDEXED */
+    testcase( i==3 ); /* INDEX */
+    testcase( i==4 ); /* DESC */
+    testcase( i==5 ); /* ESCAPE */
+    testcase( i==6 ); /* EACH */
+    testcase( i==7 ); /* CHECK */
+    testcase( i==8 ); /* KEY */
+    testcase( i==9 ); /* BEFORE */
+    testcase( i==10 ); /* FOREIGN */
+    testcase( i==11 ); /* FOR */
+    testcase( i==12 ); /* IGNORE */
+    testcase( i==13 ); /* REGEXP */
+    testcase( i==14 ); /* EXPLAIN */
+    testcase( i==15 ); /* INSTEAD */
+    testcase( i==16 ); /* ADD */
+    testcase( i==17 ); /* DATABASE */
+    testcase( i==18 ); /* AS */
+    testcase( i==19 ); /* SELECT */
+    testcase( i==20 ); /* TABLE */
+    testcase( i==21 ); /* LEFT */
+    testcase( i==22 ); /* THEN */
+    testcase( i==23 ); /* END */
+    testcase( i==24 ); /* DEFERRABLE */
+    testcase( i==25 ); /* ELSE */
+    testcase( i==26 ); /* EXCLUDE */
+    testcase( i==27 ); /* DELETE */
+    testcase( i==28 ); /* TEMPORARY */
+    testcase( i==29 ); /* TEMP */
+    testcase( i==30 ); /* OR */
+    testcase( i==31 ); /* ISNULL */
+    testcase( i==32 ); /* NULLS */
+    testcase( i==33 ); /* SAVEPOINT */
+    testcase( i==34 ); /* INTERSECT */
+    testcase( i==35 ); /* TIES */
+    testcase( i==36 ); /* NOTNULL */
+    testcase( i==37 ); /* NOT */
+    testcase( i==38 ); /* NO */
+    testcase( i==39 ); /* NULL */
+    testcase( i==40 ); /* LIKE */
+    testcase( i==41 ); /* EXCEPT */
+    testcase( i==42 ); /* TRANSACTION */
+    testcase( i==43 ); /* ACTION */
+    testcase( i==44 ); /* ON */
+    testcase( i==45 ); /* NATURAL */
+    testcase( i==46 ); /* ALTER */
+    testcase( i==47 ); /* RAISE */
+    testcase( i==48 ); /* EXCLUSIVE */
+    testcase( i==49 ); /* EXISTS */
+    testcase( i==50 ); /* CONSTRAINT */
+    testcase( i==51 ); /* INTO */
+    testcase( i==52 ); /* OFFSET */
+    testcase( i==53 ); /* OF */
+    testcase( i==54 ); /* SET */
+    testcase( i==55 ); /* TRIGGER */
+    testcase( i==56 ); /* RANGE */
+    testcase( i==57 ); /* GENERATED */
+    testcase( i==58 ); /* DETACH */
+    testcase( i==59 ); /* HAVING */
+    testcase( i==60 ); /* GLOB */
+    testcase( i==61 ); /* BEGIN */
+    testcase( i==62 ); /* INNER */
+    testcase( i==63 ); /* REFERENCES */
+    testcase( i==64 ); /* UNIQUE */
+    testcase( i==65 ); /* QUERY */
+    testcase( i==66 ); /* WITHOUT */
+    testcase( i==67 ); /* WITH */
+    testcase( i==68 ); /* OUTER */
+    testcase( i==69 ); /* RELEASE */
+    testcase( i==70 ); /* ATTACH */
+    testcase( i==71 ); /* BETWEEN */
+    testcase( i==72 ); /* NOTHING */
+    testcase( i==73 ); /* GROUPS */
+    testcase( i==74 ); /* GROUP */
+    testcase( i==75 ); /* CASCADE */
+    testcase( i==76 ); /* ASC */
+    testcase( i==77 ); /* DEFAULT */
+    testcase( i==78 ); /* CASE */
+    testcase( i==79 ); /* COLLATE */
+    testcase( i==80 ); /* CREATE */
+    testcase( i==81 ); /* CURRENT_DATE */
+    testcase( i==82 ); /* IMMEDIATE */
+    testcase( i==83 ); /* JOIN */
+    testcase( i==84 ); /* INSERT */
+    testcase( i==85 ); /* MATCH */
+    testcase( i==86 ); /* PLAN */
+    testcase( i==87 ); /* ANALYZE */
+    testcase( i==88 ); /* PRAGMA */
+    testcase( i==89 ); /* MATERIALIZED */
+    testcase( i==90 ); /* DEFERRED */
+    testcase( i==91 ); /* DISTINCT */
+    testcase( i==92 ); /* IS */
+    testcase( i==93 ); /* UPDATE */
+    testcase( i==94 ); /* VALUES */
+    testcase( i==95 ); /* VIRTUAL */
+    testcase( i==96 ); /* ALWAYS */
+    testcase( i==97 ); /* WHEN */
+    testcase( i==98 ); /* WHERE */
+    testcase( i==99 ); /* RECURSIVE */
+    testcase( i==100 ); /* ABORT */
+    testcase( i==101 ); /* AFTER */
+    testcase( i==102 ); /* RENAME */
+    testcase( i==103 ); /* AND */
+    testcase( i==104 ); /* DROP */
+    testcase( i==105 ); /* PARTITION */
+    testcase( i==106 ); /* AUTOINCREMENT */
+    testcase( i==107 ); /* TO */
+    testcase( i==108 ); /* IN */
+    testcase( i==109 ); /* CAST */
+    testcase( i==110 ); /* COLUMN */
+    testcase( i==111 ); /* COMMIT */
+    testcase( i==112 ); /* CONFLICT */
+    testcase( i==113 ); /* CROSS */
+    testcase( i==114 ); /* CURRENT_TIMESTAMP */
+    testcase( i==115 ); /* CURRENT_TIME */
+    testcase( i==116 ); /* CURRENT */
+    testcase( i==117 ); /* PRECEDING */
+    testcase( i==118 ); /* FAIL */
+    testcase( i==119 ); /* LAST */
+    testcase( i==120 ); /* FILTER */
+    testcase( i==121 ); /* REPLACE */
+    testcase( i==122 ); /* FIRST */
+    testcase( i==123 ); /* FOLLOWING */
+    testcase( i==124 ); /* FROM */
+    testcase( i==125 ); /* FULL */
+    testcase( i==126 ); /* LIMIT */
+    testcase( i==127 ); /* IF */
+    testcase( i==128 ); /* ORDER */
+    testcase( i==129 ); /* RESTRICT */
+    testcase( i==130 ); /* OTHERS */
+    testcase( i==131 ); /* OVER */
+    testcase( i==132 ); /* RETURNING */
+    testcase( i==133 ); /* RIGHT */
+    testcase( i==134 ); /* ROLLBACK */
+    testcase( i==135 ); /* ROWS */
+    testcase( i==136 ); /* ROW */
+    testcase( i==137 ); /* UNBOUNDED */
+    testcase( i==138 ); /* UNION */
+    testcase( i==139 ); /* USING */
+    testcase( i==140 ); /* VACUUM */
+    testcase( i==141 ); /* VIEW */
+    testcase( i==142 ); /* WINDOW */
+    testcase( i==143 ); /* DO */
+    testcase( i==144 ); /* BY */
+    testcase( i==145 ); /* INITIALLY */
+    testcase( i==146 ); /* ALL */
+    testcase( i==147 ); /* PRIMARY */
+    *pType = aKWCode[i];
+    break;
+  }
+  return n;
+}
+SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char *z, int n){
+  int id = TK_ID;
+  if( n>=2 ) keywordCode((char*)z, n, &id);
+  return id;
+}
+#define SQLITE_N_KEYWORD 147
+SQLITE_API int sqlite3_keyword_name(int i,const char **pzName,int *pnName){
+  if( i<0 || i>=SQLITE_N_KEYWORD ) return SQLITE_ERROR;
+  i++;
+  *pzName = zKWText + aKWOffset[i];
+  *pnName = aKWLen[i];
+  return SQLITE_OK;
+}
+SQLITE_API int sqlite3_keyword_count(void){ return SQLITE_N_KEYWORD; }
+SQLITE_API int sqlite3_keyword_check(const char *zName, int nName){
+  return TK_ID!=sqlite3KeywordCode((const u8*)zName, nName);
+}
+
+/************** End of keywordhash.h *****************************************/
+/************** Continuing where we left off in tokenize.c *******************/
+
+
+/*
+** If X is a character that can be used in an identifier then
+** IdChar(X) will be true.  Otherwise it is false.
+**
+** For ASCII, any character with the high-order bit set is
+** allowed in an identifier.  For 7-bit characters,
+** sqlite3IsIdChar[X] must be 1.
+**
+** For EBCDIC, the rules are more complex but have the same
+** end result.
+**
+** Ticket #1066.  the SQL standard does not allow '$' in the
+** middle of identifiers.  But many SQL implementations do.
+** SQLite will allow '$' in identifiers for compatibility.
+** But the feature is undocumented.
+*/
+#ifdef SQLITE_ASCII
+#define IdChar(C)  ((sqlite3CtypeMap[(unsigned char)C]&0x46)!=0)
+#endif
+#ifdef SQLITE_EBCDIC
+SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[] = {
+/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
+    0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 4x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0,  /* 5x */
+    0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0,  /* 6x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,  /* 7x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0,  /* 8x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0,  /* 9x */
+    1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0,  /* Ax */
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* Bx */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,  /* Cx */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,  /* Dx */
+    0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,  /* Ex */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0,  /* Fx */
+};
+#define IdChar(C)  (((c=C)>=0x42 && sqlite3IsEbcdicIdChar[c-0x40]))
+#endif
+
+/* Make the IdChar function accessible from ctime.c and alter.c */
+SQLITE_PRIVATE int sqlite3IsIdChar(u8 c){ return IdChar(c); }
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** Return the id of the next token in string (*pz). Before returning, set
+** (*pz) to point to the byte following the parsed token.
+*/
+static int getToken(const unsigned char **pz){
+  const unsigned char *z = *pz;
+  int t;                          /* Token type to return */
+  do {
+    z += sqlite3GetToken(z, &t);
+  }while( t==TK_SPACE );
+  if( t==TK_ID
+   || t==TK_STRING
+   || t==TK_JOIN_KW
+   || t==TK_WINDOW
+   || t==TK_OVER
+   || sqlite3ParserFallback(t)==TK_ID
+  ){
+    t = TK_ID;
+  }
+  *pz = z;
+  return t;
+}
+
+/*
+** The following three functions are called immediately after the tokenizer
+** reads the keywords WINDOW, OVER and FILTER, respectively, to determine
+** whether the token should be treated as a keyword or an SQL identifier.
+** This cannot be handled by the usual lemon %fallback method, due to
+** the ambiguity in some constructions. e.g.
+**
+**   SELECT sum(x) OVER ...
+**
+** In the above, "OVER" might be a keyword, or it might be an alias for the
+** sum(x) expression. If a "%fallback ID OVER" directive were added to
+** grammar, then SQLite would always treat "OVER" as an alias, making it
+** impossible to call a window-function without a FILTER clause.
+**
+** WINDOW is treated as a keyword if:
+**
+**   * the following token is an identifier, or a keyword that can fallback
+**     to being an identifier, and
+**   * the token after than one is TK_AS.
+**
+** OVER is a keyword if:
+**
+**   * the previous token was TK_RP, and
+**   * the next token is either TK_LP or an identifier.
+**
+** FILTER is a keyword if:
+**
+**   * the previous token was TK_RP, and
+**   * the next token is TK_LP.
+*/
+static int analyzeWindowKeyword(const unsigned char *z){
+  int t;
+  t = getToken(&z);
+  if( t!=TK_ID ) return TK_ID;
+  t = getToken(&z);
+  if( t!=TK_AS ) return TK_ID;
+  return TK_WINDOW;
+}
+static int analyzeOverKeyword(const unsigned char *z, int lastToken){
+  if( lastToken==TK_RP ){
+    int t = getToken(&z);
+    if( t==TK_LP || t==TK_ID ) return TK_OVER;
+  }
+  return TK_ID;
+}
+static int analyzeFilterKeyword(const unsigned char *z, int lastToken){
+  if( lastToken==TK_RP && getToken(&z)==TK_LP ){
+    return TK_FILTER;
+  }
+  return TK_ID;
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** Return the length (in bytes) of the token that begins at z[0].
+** Store the token type in *tokenType before returning.
+*/
+SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *z, int *tokenType){
+  int i, c;
+  switch( aiClass[*z] ){  /* Switch on the character-class of the first byte
+                          ** of the token. See the comment on the CC_ defines
+                          ** above. */
+    case CC_SPACE: {
+      testcase( z[0]==' ' );
+      testcase( z[0]=='\t' );
+      testcase( z[0]=='\n' );
+      testcase( z[0]=='\f' );
+      testcase( z[0]=='\r' );
+      for(i=1; sqlite3Isspace(z[i]); i++){}
+      *tokenType = TK_SPACE;
+      return i;
+    }
+    case CC_MINUS: {
+      if( z[1]=='-' ){
+        for(i=2; (c=z[i])!=0 && c!='\n'; i++){}
+        *tokenType = TK_COMMENT;
+        return i;
+      }else if( z[1]=='>' ){
+        *tokenType = TK_PTR;
+        return 2 + (z[2]=='>');
+      }
+      *tokenType = TK_MINUS;
+      return 1;
+    }
+    case CC_LP: {
+      *tokenType = TK_LP;
+      return 1;
+    }
+    case CC_RP: {
+      *tokenType = TK_RP;
+      return 1;
+    }
+    case CC_SEMI: {
+      *tokenType = TK_SEMI;
+      return 1;
+    }
+    case CC_PLUS: {
+      *tokenType = TK_PLUS;
+      return 1;
+    }
+    case CC_STAR: {
+      *tokenType = TK_STAR;
+      return 1;
+    }
+    case CC_SLASH: {
+      if( z[1]!='*' || z[2]==0 ){
+        *tokenType = TK_SLASH;
+        return 1;
+      }
+      for(i=3, c=z[2]; (c!='*' || z[i]!='/') && (c=z[i])!=0; i++){}
+      if( c ) i++;
+      *tokenType = TK_COMMENT;
+      return i;
+    }
+    case CC_PERCENT: {
+      *tokenType = TK_REM;
+      return 1;
+    }
+    case CC_EQ: {
+      *tokenType = TK_EQ;
+      return 1 + (z[1]=='=');
+    }
+    case CC_LT: {
+      if( (c=z[1])=='=' ){
+        *tokenType = TK_LE;
+        return 2;
+      }else if( c=='>' ){
+        *tokenType = TK_NE;
+        return 2;
+      }else if( c=='<' ){
+        *tokenType = TK_LSHIFT;
+        return 2;
+      }else{
+        *tokenType = TK_LT;
+        return 1;
+      }
+    }
+    case CC_GT: {
+      if( (c=z[1])=='=' ){
+        *tokenType = TK_GE;
+        return 2;
+      }else if( c=='>' ){
+        *tokenType = TK_RSHIFT;
+        return 2;
+      }else{
+        *tokenType = TK_GT;
+        return 1;
+      }
+    }
+    case CC_BANG: {
+      if( z[1]!='=' ){
+        *tokenType = TK_ILLEGAL;
+        return 1;
+      }else{
+        *tokenType = TK_NE;
+        return 2;
+      }
+    }
+    case CC_PIPE: {
+      if( z[1]!='|' ){
+        *tokenType = TK_BITOR;
+        return 1;
+      }else{
+        *tokenType = TK_CONCAT;
+        return 2;
+      }
+    }
+    case CC_COMMA: {
+      *tokenType = TK_COMMA;
+      return 1;
+    }
+    case CC_AND: {
+      *tokenType = TK_BITAND;
+      return 1;
+    }
+    case CC_TILDA: {
+      *tokenType = TK_BITNOT;
+      return 1;
+    }
+    case CC_QUOTE: {
+      int delim = z[0];
+      testcase( delim=='`' );
+      testcase( delim=='\'' );
+      testcase( delim=='"' );
+      for(i=1; (c=z[i])!=0; i++){
+        if( c==delim ){
+          if( z[i+1]==delim ){
+            i++;
+          }else{
+            break;
+          }
+        }
+      }
+      if( c=='\'' ){
+        *tokenType = TK_STRING;
+        return i+1;
+      }else if( c!=0 ){
+        *tokenType = TK_ID;
+        return i+1;
+      }else{
+        *tokenType = TK_ILLEGAL;
+        return i;
+      }
+    }
+    case CC_DOT: {
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      if( !sqlite3Isdigit(z[1]) )
+#endif
+      {
+        *tokenType = TK_DOT;
+        return 1;
+      }
+      /* If the next character is a digit, this is a floating point
+      ** number that begins with ".".  Fall thru into the next case */
+      /* no break */ deliberate_fall_through
+    }
+    case CC_DIGIT: {
+      testcase( z[0]=='0' );  testcase( z[0]=='1' );  testcase( z[0]=='2' );
+      testcase( z[0]=='3' );  testcase( z[0]=='4' );  testcase( z[0]=='5' );
+      testcase( z[0]=='6' );  testcase( z[0]=='7' );  testcase( z[0]=='8' );
+      testcase( z[0]=='9' );  testcase( z[0]=='.' );
+      *tokenType = TK_INTEGER;
+#ifndef SQLITE_OMIT_HEX_INTEGER
+      if( z[0]=='0' && (z[1]=='x' || z[1]=='X') && sqlite3Isxdigit(z[2]) ){
+        for(i=3; 1; i++){
+          if( sqlite3Isxdigit(z[i])==0 ){
+            if( z[i]==SQLITE_DIGIT_SEPARATOR ){
+              *tokenType = TK_QNUMBER;
+            }else{
+              break;
+            }
+          }
+        }
+      }else
+#endif
+        {
+        for(i=0; 1; i++){
+          if( sqlite3Isdigit(z[i])==0 ){
+            if( z[i]==SQLITE_DIGIT_SEPARATOR ){
+              *tokenType = TK_QNUMBER;
+            }else{
+              break;
+            }
+          }
+        }
+#ifndef SQLITE_OMIT_FLOATING_POINT
+        if( z[i]=='.' ){
+          if( *tokenType==TK_INTEGER ) *tokenType = TK_FLOAT;
+          for(i++; 1; i++){
+            if( sqlite3Isdigit(z[i])==0 ){
+              if( z[i]==SQLITE_DIGIT_SEPARATOR ){
+                *tokenType = TK_QNUMBER;
+              }else{
+                break;
+              }
+            }
+          }
+        }
+        if( (z[i]=='e' || z[i]=='E') &&
+             ( sqlite3Isdigit(z[i+1])
+              || ((z[i+1]=='+' || z[i+1]=='-') && sqlite3Isdigit(z[i+2]))
+             )
+        ){
+          if( *tokenType==TK_INTEGER ) *tokenType = TK_FLOAT;
+          for(i+=2; 1; i++){
+            if( sqlite3Isdigit(z[i])==0 ){
+              if( z[i]==SQLITE_DIGIT_SEPARATOR ){
+                *tokenType = TK_QNUMBER;
+              }else{
+                break;
+              }
+            }
+          }
+        }
+#endif
+      }
+      while( IdChar(z[i]) ){
+        *tokenType = TK_ILLEGAL;
+        i++;
+      }
+      return i;
+    }
+    case CC_QUOTE2: {
+      for(i=1, c=z[0]; c!=']' && (c=z[i])!=0; i++){}
+      *tokenType = c==']' ? TK_ID : TK_ILLEGAL;
+      return i;
+    }
+    case CC_VARNUM: {
+      *tokenType = TK_VARIABLE;
+      for(i=1; sqlite3Isdigit(z[i]); i++){}
+      return i;
+    }
+    case CC_DOLLAR:
+    case CC_VARALPHA: {
+      int n = 0;
+      testcase( z[0]=='$' );  testcase( z[0]=='@' );
+      testcase( z[0]==':' );  testcase( z[0]=='#' );
+      *tokenType = TK_VARIABLE;
+      for(i=1; (c=z[i])!=0; i++){
+        if( IdChar(c) ){
+          n++;
+#ifndef SQLITE_OMIT_TCL_VARIABLE
+        }else if( c=='(' && n>0 ){
+          do{
+            i++;
+          }while( (c=z[i])!=0 && !sqlite3Isspace(c) && c!=')' );
+          if( c==')' ){
+            i++;
+          }else{
+            *tokenType = TK_ILLEGAL;
+          }
+          break;
+        }else if( c==':' && z[i+1]==':' ){
+          i++;
+#endif
+        }else{
+          break;
+        }
+      }
+      if( n==0 ) *tokenType = TK_ILLEGAL;
+      return i;
+    }
+    case CC_KYWD0: {
+      if( aiClass[z[1]]>CC_KYWD ){ i = 1;  break; }
+      for(i=2; aiClass[z[i]]<=CC_KYWD; i++){}
+      if( IdChar(z[i]) ){
+        /* This token started out using characters that can appear in keywords,
+        ** but z[i] is a character not allowed within keywords, so this must
+        ** be an identifier instead */
+        i++;
+        break;
+      }
+      *tokenType = TK_ID;
+      return keywordCode((char*)z, i, tokenType);
+    }
+    case CC_X: {
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+      testcase( z[0]=='x' ); testcase( z[0]=='X' );
+      if( z[1]=='\'' ){
+        *tokenType = TK_BLOB;
+        for(i=2; sqlite3Isxdigit(z[i]); i++){}
+        if( z[i]!='\'' || i%2 ){
+          *tokenType = TK_ILLEGAL;
+          while( z[i] && z[i]!='\'' ){ i++; }
+        }
+        if( z[i] ) i++;
+        return i;
+      }
+#endif
+      /* If it is not a BLOB literal, then it must be an ID, since no
+      ** SQL keywords start with the letter 'x'.  Fall through */
+      /* no break */ deliberate_fall_through
+    }
+    case CC_KYWD:
+    case CC_ID: {
+      i = 1;
+      break;
+    }
+    case CC_BOM: {
+      if( z[1]==0xbb && z[2]==0xbf ){
+        *tokenType = TK_SPACE;
+        return 3;
+      }
+      i = 1;
+      break;
+    }
+    case CC_NUL: {
+      *tokenType = TK_ILLEGAL;
+      return 0;
+    }
+    default: {
+      *tokenType = TK_ILLEGAL;
+      return 1;
+    }
+  }
+  while( IdChar(z[i]) ){ i++; }
+  *tokenType = TK_ID;
+  return i;
+}
+
+/*
+** Run the parser on the given SQL string.
+*/
+SQLITE_PRIVATE int sqlite3RunParser(Parse *pParse, const char *zSql){
+  int nErr = 0;                   /* Number of errors encountered */
+  void *pEngine;                  /* The LEMON-generated LALR(1) parser */
+  int n = 0;                      /* Length of the next token token */
+  int tokenType;                  /* type of the next token */
+  int lastTokenParsed = -1;       /* type of the previous token */
+  sqlite3 *db = pParse->db;       /* The database connection */
+  int mxSqlLen;                   /* Max length of an SQL string */
+  Parse *pParentParse = 0;        /* Outer parse context, if any */
+#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
+  yyParser sEngine;    /* Space to hold the Lemon-generated Parser object */
+#endif
+  VVA_ONLY( u8 startedWithOom = db->mallocFailed );
+
+  assert( zSql!=0 );
+  mxSqlLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
+  if( db->nVdbeActive==0 ){
+    AtomicStore(&db->u1.isInterrupted, 0);
+  }
+  pParse->rc = SQLITE_OK;
+  pParse->zTail = zSql;
+#ifdef SQLITE_DEBUG
+  if( db->flags & SQLITE_ParserTrace ){
+    printf("parser: [[[%s]]]\n", zSql);
+    sqlite3ParserTrace(stdout, "parser: ");
+  }else{
+    sqlite3ParserTrace(0, 0);
+  }
+#endif
+#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
+  pEngine = &sEngine;
+  sqlite3ParserInit(pEngine, pParse);
+#else
+  pEngine = sqlite3ParserAlloc(sqlite3Malloc, pParse);
+  if( pEngine==0 ){
+    sqlite3OomFault(db);
+    return SQLITE_NOMEM_BKPT;
+  }
+#endif
+  assert( pParse->pNewTable==0 );
+  assert( pParse->pNewTrigger==0 );
+  assert( pParse->nVar==0 );
+  assert( pParse->pVList==0 );
+  pParentParse = db->pParse;
+  db->pParse = pParse;
+  while( 1 ){
+    n = sqlite3GetToken((u8*)zSql, &tokenType);
+    mxSqlLen -= n;
+    if( mxSqlLen<0 ){
+      pParse->rc = SQLITE_TOOBIG;
+      pParse->nErr++;
+      break;
+    }
+#ifndef SQLITE_OMIT_WINDOWFUNC
+    if( tokenType>=TK_WINDOW ){
+      assert( tokenType==TK_SPACE || tokenType==TK_OVER || tokenType==TK_FILTER
+           || tokenType==TK_ILLEGAL || tokenType==TK_WINDOW
+           || tokenType==TK_QNUMBER || tokenType==TK_COMMENT
+      );
+#else
+    if( tokenType>=TK_SPACE ){
+      assert( tokenType==TK_SPACE || tokenType==TK_ILLEGAL
+           || tokenType==TK_QNUMBER || tokenType==TK_COMMENT
+      );
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+      if( AtomicLoad(&db->u1.isInterrupted) ){
+        pParse->rc = SQLITE_INTERRUPT;
+        pParse->nErr++;
+        break;
+      }
+      if( tokenType==TK_SPACE ){
+        zSql += n;
+        continue;
+      }
+      if( zSql[0]==0 ){
+        /* Upon reaching the end of input, call the parser two more times
+        ** with tokens TK_SEMI and 0, in that order. */
+        if( lastTokenParsed==TK_SEMI ){
+          tokenType = 0;
+        }else if( lastTokenParsed==0 ){
+          break;
+        }else{
+          tokenType = TK_SEMI;
+        }
+        n = 0;
+#ifndef SQLITE_OMIT_WINDOWFUNC
+      }else if( tokenType==TK_WINDOW ){
+        assert( n==6 );
+        tokenType = analyzeWindowKeyword((const u8*)&zSql[6]);
+      }else if( tokenType==TK_OVER ){
+        assert( n==4 );
+        tokenType = analyzeOverKeyword((const u8*)&zSql[4], lastTokenParsed);
+      }else if( tokenType==TK_FILTER ){
+        assert( n==6 );
+        tokenType = analyzeFilterKeyword((const u8*)&zSql[6], lastTokenParsed);
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+      }else if( tokenType==TK_COMMENT && (db->flags & SQLITE_Comments)!=0 ){
+        zSql += n;
+        continue;
+      }else if( tokenType!=TK_QNUMBER ){
+        Token x;
+        x.z = zSql;
+        x.n = n;
+        sqlite3ErrorMsg(pParse, "unrecognized token: \"%T\"", &x);
+        break;
+      }
+    }
+    pParse->sLastToken.z = zSql;
+    pParse->sLastToken.n = n;
+    sqlite3Parser(pEngine, tokenType, pParse->sLastToken);
+    lastTokenParsed = tokenType;
+    zSql += n;
+    assert( db->mallocFailed==0 || pParse->rc!=SQLITE_OK || startedWithOom );
+    if( pParse->rc!=SQLITE_OK ) break;
+  }
+  assert( nErr==0 );
+#ifdef YYTRACKMAXSTACKDEPTH
+  sqlite3_mutex_enter(sqlite3MallocMutex());
+  sqlite3StatusHighwater(SQLITE_STATUS_PARSER_STACK,
+      sqlite3ParserStackPeak(pEngine)
+  );
+  sqlite3_mutex_leave(sqlite3MallocMutex());
+#endif /* YYDEBUG */
+#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
+  sqlite3ParserFinalize(pEngine);
+#else
+  sqlite3ParserFree(pEngine, sqlite3_free);
+#endif
+  if( db->mallocFailed ){
+    pParse->rc = SQLITE_NOMEM_BKPT;
+  }
+  if( pParse->zErrMsg || (pParse->rc!=SQLITE_OK && pParse->rc!=SQLITE_DONE) ){
+    if( pParse->zErrMsg==0 ){
+      pParse->zErrMsg = sqlite3MPrintf(db, "%s", sqlite3ErrStr(pParse->rc));
+    }
+    if( (pParse->prepFlags & SQLITE_PREPARE_DONT_LOG)==0 ){
+      sqlite3_log(pParse->rc, "%s in \"%s\"", pParse->zErrMsg, pParse->zTail);
+    }
+    nErr++;
+  }
+  pParse->zTail = zSql;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3_free(pParse->apVtabLock);
+#endif
+
+  if( pParse->pNewTable && !IN_SPECIAL_PARSE ){
+    /* If the pParse->declareVtab flag is set, do not delete any table
+    ** structure built up in pParse->pNewTable. The calling code (see vtab.c)
+    ** will take responsibility for freeing the Table structure.
+    */
+    sqlite3DeleteTable(db, pParse->pNewTable);
+  }
+  if( pParse->pNewTrigger && !IN_RENAME_OBJECT ){
+    sqlite3DeleteTrigger(db, pParse->pNewTrigger);
+  }
+  if( pParse->pVList ) sqlite3DbNNFreeNN(db, pParse->pVList);
+  db->pParse = pParentParse;
+  assert( nErr==0 || pParse->rc!=SQLITE_OK );
+  return nErr;
+}
+
+
+#ifdef SQLITE_ENABLE_NORMALIZE
+/*
+** Insert a single space character into pStr if the current string
+** ends with an identifier
+*/
+static void addSpaceSeparator(sqlite3_str *pStr){
+  if( pStr->nChar && sqlite3IsIdChar(pStr->zText[pStr->nChar-1]) ){
+    sqlite3_str_append(pStr, " ", 1);
+  }
+}
+
+/*
+** Compute a normalization of the SQL given by zSql[0..nSql-1].  Return
+** the normalization in space obtained from sqlite3DbMalloc().  Or return
+** NULL if anything goes wrong or if zSql is NULL.
+*/
+SQLITE_PRIVATE char *sqlite3Normalize(
+  Vdbe *pVdbe,       /* VM being reprepared */
+  const char *zSql   /* The original SQL string */
+){
+  sqlite3 *db;       /* The database connection */
+  int i;             /* Next unread byte of zSql[] */
+  int n;             /* length of current token */
+  int tokenType;     /* type of current token */
+  int prevType = 0;  /* Previous non-whitespace token */
+  int nParen;        /* Number of nested levels of parentheses */
+  int iStartIN;      /* Start of RHS of IN operator in z[] */
+  int nParenAtIN;    /* Value of nParent at start of RHS of IN operator */
+  u32 j;             /* Bytes of normalized SQL generated so far */
+  sqlite3_str *pStr; /* The normalized SQL string under construction */
+
+  db = sqlite3VdbeDb(pVdbe);
+  tokenType = -1;
+  nParen = iStartIN = nParenAtIN = 0;
+  pStr = sqlite3_str_new(db);
+  assert( pStr!=0 );  /* sqlite3_str_new() never returns NULL */
+  for(i=0; zSql[i] && pStr->accError==0; i+=n){
+    if( tokenType!=TK_SPACE ){
+      prevType = tokenType;
+    }
+    n = sqlite3GetToken((unsigned char*)zSql+i, &tokenType);
+    if( NEVER(n<=0) ) break;
+    switch( tokenType ){
+      case TK_COMMENT:
+      case TK_SPACE: {
+        break;
+      }
+      case TK_NULL: {
+        if( prevType==TK_IS || prevType==TK_NOT ){
+          sqlite3_str_append(pStr, " NULL", 5);
+          break;
+        }
+        /* Fall through */
+      }
+      case TK_STRING:
+      case TK_INTEGER:
+      case TK_FLOAT:
+      case TK_VARIABLE:
+      case TK_BLOB: {
+        sqlite3_str_append(pStr, "?", 1);
+        break;
+      }
+      case TK_LP: {
+        nParen++;
+        if( prevType==TK_IN ){
+          iStartIN = pStr->nChar;
+          nParenAtIN = nParen;
+        }
+        sqlite3_str_append(pStr, "(", 1);
+        break;
+      }
+      case TK_RP: {
+        if( iStartIN>0 && nParen==nParenAtIN ){
+          assert( pStr->nChar>=(u32)iStartIN );
+          pStr->nChar = iStartIN+1;
+          sqlite3_str_append(pStr, "?,?,?", 5);
+          iStartIN = 0;
+        }
+        nParen--;
+        sqlite3_str_append(pStr, ")", 1);
+        break;
+      }
+      case TK_ID: {
+        iStartIN = 0;
+        j = pStr->nChar;
+        if( sqlite3Isquote(zSql[i]) ){
+          char *zId = sqlite3DbStrNDup(db, zSql+i, n);
+          int nId;
+          int eType = 0;
+          if( zId==0 ) break;
+          sqlite3Dequote(zId);
+          if( zSql[i]=='"' && sqlite3VdbeUsesDoubleQuotedString(pVdbe, zId) ){
+            sqlite3_str_append(pStr, "?", 1);
+            sqlite3DbFree(db, zId);
+            break;
+          }
+          nId = sqlite3Strlen30(zId);
+          if( sqlite3GetToken((u8*)zId, &eType)==nId && eType==TK_ID ){
+            addSpaceSeparator(pStr);
+            sqlite3_str_append(pStr, zId, nId);
+          }else{
+            sqlite3_str_appendf(pStr, "\"%w\"", zId);
+          }
+          sqlite3DbFree(db, zId);
+        }else{
+          addSpaceSeparator(pStr);
+          sqlite3_str_append(pStr, zSql+i, n);
+        }
+        while( j<pStr->nChar ){
+          pStr->zText[j] = sqlite3Tolower(pStr->zText[j]);
+          j++;
+        }
+        break;
+      }
+      case TK_SELECT: {
+        iStartIN = 0;
+        /* fall through */
+      }
+      default: {
+        if( sqlite3IsIdChar(zSql[i]) ) addSpaceSeparator(pStr);
+        j = pStr->nChar;
+        sqlite3_str_append(pStr, zSql+i, n);
+        while( j<pStr->nChar ){
+          pStr->zText[j] = sqlite3Toupper(pStr->zText[j]);
+          j++;
+        }
+        break;
+      }
+    }
+  }
+  if( tokenType!=TK_SEMI ) sqlite3_str_append(pStr, ";", 1);
+  return sqlite3_str_finish(pStr);
+}
+#endif /* SQLITE_ENABLE_NORMALIZE */
+
+/************** End of tokenize.c ********************************************/
+/************** Begin file complete.c ****************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** An tokenizer for SQL
+**
+** This file contains C code that implements the sqlite3_complete() API.
+** This code used to be part of the tokenizer.c source file.  But by
+** separating it out, the code will be automatically omitted from
+** static links that do not use it.
+*/
+/* #include "sqliteInt.h" */
+#ifndef SQLITE_OMIT_COMPLETE
+
+/*
+** This is defined in tokenize.c.  We just have to import the definition.
+*/
+#ifndef SQLITE_AMALGAMATION
+#ifdef SQLITE_ASCII
+#define IdChar(C)  ((sqlite3CtypeMap[(unsigned char)C]&0x46)!=0)
+#endif
+#ifdef SQLITE_EBCDIC
+SQLITE_PRIVATE const char sqlite3IsEbcdicIdChar[];
+#define IdChar(C)  (((c=C)>=0x42 && sqlite3IsEbcdicIdChar[c-0x40]))
+#endif
+#endif /* SQLITE_AMALGAMATION */
+
+
+/*
+** Token types used by the sqlite3_complete() routine.  See the header
+** comments on that procedure for additional information.
+*/
+#define tkSEMI    0
+#define tkWS      1
+#define tkOTHER   2
+#ifndef SQLITE_OMIT_TRIGGER
+#define tkEXPLAIN 3
+#define tkCREATE  4
+#define tkTEMP    5
+#define tkTRIGGER 6
+#define tkEND     7
+#endif
+
+/*
+** Return TRUE if the given SQL string ends in a semicolon.
+**
+** Special handling is require for CREATE TRIGGER statements.
+** Whenever the CREATE TRIGGER keywords are seen, the statement
+** must end with ";END;".
+**
+** This implementation uses a state machine with 8 states:
+**
+**   (0) INVALID   We have not yet seen a non-whitespace character.
+**
+**   (1) START     At the beginning or end of an SQL statement.  This routine
+**                 returns 1 if it ends in the START state and 0 if it ends
+**                 in any other state.
+**
+**   (2) NORMAL    We are in the middle of statement which ends with a single
+**                 semicolon.
+**
+**   (3) EXPLAIN   The keyword EXPLAIN has been seen at the beginning of
+**                 a statement.
+**
+**   (4) CREATE    The keyword CREATE has been seen at the beginning of a
+**                 statement, possibly preceded by EXPLAIN and/or followed by
+**                 TEMP or TEMPORARY
+**
+**   (5) TRIGGER   We are in the middle of a trigger definition that must be
+**                 ended by a semicolon, the keyword END, and another semicolon.
+**
+**   (6) SEMI      We've seen the first semicolon in the ";END;" that occurs at
+**                 the end of a trigger definition.
+**
+**   (7) END       We've seen the ";END" of the ";END;" that occurs at the end
+**                 of a trigger definition.
+**
+** Transitions between states above are determined by tokens extracted
+** from the input.  The following tokens are significant:
+**
+**   (0) tkSEMI      A semicolon.
+**   (1) tkWS        Whitespace.
+**   (2) tkOTHER     Any other SQL token.
+**   (3) tkEXPLAIN   The "explain" keyword.
+**   (4) tkCREATE    The "create" keyword.
+**   (5) tkTEMP      The "temp" or "temporary" keyword.
+**   (6) tkTRIGGER   The "trigger" keyword.
+**   (7) tkEND       The "end" keyword.
+**
+** Whitespace never causes a state transition and is always ignored.
+** This means that a SQL string of all whitespace is invalid.
+**
+** If we compile with SQLITE_OMIT_TRIGGER, all of the computation needed
+** to recognize the end of a trigger can be omitted.  All we have to do
+** is look for a semicolon that is not part of an string or comment.
+*/
+SQLITE_API int sqlite3_complete(const char *zSql){
+  u8 state = 0;   /* Current state, using numbers defined in header comment */
+  u8 token;       /* Value of the next token */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  /* A complex statement machine used to detect the end of a CREATE TRIGGER
+  ** statement.  This is the normal case.
+  */
+  static const u8 trans[8][8] = {
+                     /* Token:                                                */
+     /* State:       **  SEMI  WS  OTHER  EXPLAIN  CREATE  TEMP  TRIGGER  END */
+     /* 0 INVALID: */ {    1,  0,     2,       3,      4,    2,       2,   2, },
+     /* 1   START: */ {    1,  1,     2,       3,      4,    2,       2,   2, },
+     /* 2  NORMAL: */ {    1,  2,     2,       2,      2,    2,       2,   2, },
+     /* 3 EXPLAIN: */ {    1,  3,     3,       2,      4,    2,       2,   2, },
+     /* 4  CREATE: */ {    1,  4,     2,       2,      2,    4,       5,   2, },
+     /* 5 TRIGGER: */ {    6,  5,     5,       5,      5,    5,       5,   5, },
+     /* 6    SEMI: */ {    6,  6,     5,       5,      5,    5,       5,   7, },
+     /* 7     END: */ {    1,  7,     5,       5,      5,    5,       5,   5, },
+  };
+#else
+  /* If triggers are not supported by this compile then the statement machine
+  ** used to detect the end of a statement is much simpler
+  */
+  static const u8 trans[3][3] = {
+                     /* Token:           */
+     /* State:       **  SEMI  WS  OTHER */
+     /* 0 INVALID: */ {    1,  0,     2, },
+     /* 1   START: */ {    1,  1,     2, },
+     /* 2  NORMAL: */ {    1,  2,     2, },
+  };
+#endif /* SQLITE_OMIT_TRIGGER */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zSql==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+
+  while( *zSql ){
+    switch( *zSql ){
+      case ';': {  /* A semicolon */
+        token = tkSEMI;
+        break;
+      }
+      case ' ':
+      case '\r':
+      case '\t':
+      case '\n':
+      case '\f': {  /* White space is ignored */
+        token = tkWS;
+        break;
+      }
+      case '/': {   /* C-style comments */
+        if( zSql[1]!='*' ){
+          token = tkOTHER;
+          break;
+        }
+        zSql += 2;
+        while( zSql[0] && (zSql[0]!='*' || zSql[1]!='/') ){ zSql++; }
+        if( zSql[0]==0 ) return 0;
+        zSql++;
+        token = tkWS;
+        break;
+      }
+      case '-': {   /* SQL-style comments from "--" to end of line */
+        if( zSql[1]!='-' ){
+          token = tkOTHER;
+          break;
+        }
+        while( *zSql && *zSql!='\n' ){ zSql++; }
+        if( *zSql==0 ) return state==1;
+        token = tkWS;
+        break;
+      }
+      case '[': {   /* Microsoft-style identifiers in [...] */
+        zSql++;
+        while( *zSql && *zSql!=']' ){ zSql++; }
+        if( *zSql==0 ) return 0;
+        token = tkOTHER;
+        break;
+      }
+      case '`':     /* Grave-accent quoted symbols used by MySQL */
+      case '"':     /* single- and double-quoted strings */
+      case '\'': {
+        int c = *zSql;
+        zSql++;
+        while( *zSql && *zSql!=c ){ zSql++; }
+        if( *zSql==0 ) return 0;
+        token = tkOTHER;
+        break;
+      }
+      default: {
+#ifdef SQLITE_EBCDIC
+        unsigned char c;
+#endif
+        if( IdChar((u8)*zSql) ){
+          /* Keywords and unquoted identifiers */
+          int nId;
+          for(nId=1; IdChar(zSql[nId]); nId++){}
+#ifdef SQLITE_OMIT_TRIGGER
+          token = tkOTHER;
+#else
+          switch( *zSql ){
+            case 'c': case 'C': {
+              if( nId==6 && sqlite3StrNICmp(zSql, "create", 6)==0 ){
+                token = tkCREATE;
+              }else{
+                token = tkOTHER;
+              }
+              break;
+            }
+            case 't': case 'T': {
+              if( nId==7 && sqlite3StrNICmp(zSql, "trigger", 7)==0 ){
+                token = tkTRIGGER;
+              }else if( nId==4 && sqlite3StrNICmp(zSql, "temp", 4)==0 ){
+                token = tkTEMP;
+              }else if( nId==9 && sqlite3StrNICmp(zSql, "temporary", 9)==0 ){
+                token = tkTEMP;
+              }else{
+                token = tkOTHER;
+              }
+              break;
+            }
+            case 'e':  case 'E': {
+              if( nId==3 && sqlite3StrNICmp(zSql, "end", 3)==0 ){
+                token = tkEND;
+              }else
+#ifndef SQLITE_OMIT_EXPLAIN
+              if( nId==7 && sqlite3StrNICmp(zSql, "explain", 7)==0 ){
+                token = tkEXPLAIN;
+              }else
+#endif
+              {
+                token = tkOTHER;
+              }
+              break;
+            }
+            default: {
+              token = tkOTHER;
+              break;
+            }
+          }
+#endif /* SQLITE_OMIT_TRIGGER */
+          zSql += nId-1;
+        }else{
+          /* Operators and special symbols */
+          token = tkOTHER;
+        }
+        break;
+      }
+    }
+    state = trans[state][token];
+    zSql++;
+  }
+  return state==1;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** This routine is the same as the sqlite3_complete() routine described
+** above, except that the parameter is required to be UTF-16 encoded, not
+** UTF-8.
+*/
+SQLITE_API int sqlite3_complete16(const void *zSql){
+  sqlite3_value *pVal;
+  char const *zSql8;
+  int rc;
+
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+  pVal = sqlite3ValueNew(0);
+  sqlite3ValueSetStr(pVal, -1, zSql, SQLITE_UTF16NATIVE, SQLITE_STATIC);
+  zSql8 = sqlite3ValueText(pVal, SQLITE_UTF8);
+  if( zSql8 ){
+    rc = sqlite3_complete(zSql8);
+  }else{
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  sqlite3ValueFree(pVal);
+  return rc & 0xff;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+#endif /* SQLITE_OMIT_COMPLETE */
+
+/************** End of complete.c ********************************************/
+/************** Begin file main.c ********************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Main file for the SQLite library.  The routines in this file
+** implement the programmer interface to the library.  Routines in
+** other files are for internal use by SQLite and should not be
+** accessed by users of the library.
+*/
+/* #include "sqliteInt.h" */
+
+#ifdef SQLITE_ENABLE_FTS3
+/************** Include fts3.h in the middle of main.c ***********************/
+/************** Begin file fts3.h ********************************************/
+/*
+** 2006 Oct 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file is used by programs that want to link against the
+** FTS3 library.  All it does is declare the sqlite3Fts3Init() interface.
+*/
+/* #include "sqlite3.h" */
+
+#if 0
+extern "C" {
+#endif  /* __cplusplus */
+
+SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db);
+
+#if 0
+}  /* extern "C" */
+#endif  /* __cplusplus */
+
+/************** End of fts3.h ************************************************/
+/************** Continuing where we left off in main.c ***********************/
+#endif
+#ifdef SQLITE_ENABLE_RTREE
+/************** Include rtree.h in the middle of main.c **********************/
+/************** Begin file rtree.h *******************************************/
+/*
+** 2008 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file is used by programs that want to link against the
+** RTREE library.  All it does is declare the sqlite3RtreeInit() interface.
+*/
+/* #include "sqlite3.h" */
+
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+# undef SQLITE_ENABLE_RTREE
+#endif
+
+#if 0
+extern "C" {
+#endif  /* __cplusplus */
+
+SQLITE_PRIVATE int sqlite3RtreeInit(sqlite3 *db);
+
+#if 0
+}  /* extern "C" */
+#endif  /* __cplusplus */
+
+/************** End of rtree.h ***********************************************/
+/************** Continuing where we left off in main.c ***********************/
+#endif
+#if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
+/************** Include sqliteicu.h in the middle of main.c ******************/
+/************** Begin file sqliteicu.h ***************************************/
+/*
+** 2008 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file is used by programs that want to link against the
+** ICU extension.  All it does is declare the sqlite3IcuInit() interface.
+*/
+/* #include "sqlite3.h" */
+
+#if 0
+extern "C" {
+#endif  /* __cplusplus */
+
+SQLITE_PRIVATE int sqlite3IcuInit(sqlite3 *db);
+
+#if 0
+}  /* extern "C" */
+#endif  /* __cplusplus */
+
+/************** End of sqliteicu.h *******************************************/
+/************** Continuing where we left off in main.c ***********************/
+#endif
+
+/*
+** This is an extension initializer that is a no-op and always
+** succeeds, except that it fails if the fault-simulation is set
+** to 500.
+*/
+static int sqlite3TestExtInit(sqlite3 *db){
+  (void)db;
+  return sqlite3FaultSim(500);
+}
+
+
+/*
+** Forward declarations of external module initializer functions
+** for modules that need them.
+*/
+#ifdef SQLITE_ENABLE_FTS5
+SQLITE_PRIVATE int sqlite3Fts5Init(sqlite3*);
+#endif
+#ifdef SQLITE_ENABLE_STMTVTAB
+SQLITE_PRIVATE int sqlite3StmtVtabInit(sqlite3*);
+#endif
+#ifdef SQLITE_EXTRA_AUTOEXT
+int SQLITE_EXTRA_AUTOEXT(sqlite3*);
+#endif
+/*
+** An array of pointers to extension initializer functions for
+** built-in extensions.
+*/
+static int (*const sqlite3BuiltinExtensions[])(sqlite3*) = {
+#ifdef SQLITE_ENABLE_FTS3
+  sqlite3Fts3Init,
+#endif
+#ifdef SQLITE_ENABLE_FTS5
+  sqlite3Fts5Init,
+#endif
+#if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
+  sqlite3IcuInit,
+#endif
+#ifdef SQLITE_ENABLE_RTREE
+  sqlite3RtreeInit,
+#endif
+#ifdef SQLITE_ENABLE_DBPAGE_VTAB
+  sqlite3DbpageRegister,
+#endif
+#ifdef SQLITE_ENABLE_DBSTAT_VTAB
+  sqlite3DbstatRegister,
+#endif
+  sqlite3TestExtInit,
+#if !defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_JSON)
+  sqlite3JsonTableFunctions,
+#endif
+#ifdef SQLITE_ENABLE_STMTVTAB
+  sqlite3StmtVtabInit,
+#endif
+#ifdef SQLITE_ENABLE_BYTECODE_VTAB
+  sqlite3VdbeBytecodeVtabInit,
+#endif
+#ifdef SQLITE_EXTRA_AUTOEXT
+  SQLITE_EXTRA_AUTOEXT,
+#endif
+};
+
+#ifndef SQLITE_AMALGAMATION
+/* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
+** contains the text of SQLITE_VERSION macro.
+*/
+SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
+#endif
+
+/* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
+** a pointer to the to the sqlite3_version[] string constant.
+*/
+SQLITE_API const char *sqlite3_libversion(void){ return sqlite3_version; }
+
+/* IMPLEMENTATION-OF: R-25063-23286 The sqlite3_sourceid() function returns a
+** pointer to a string constant whose value is the same as the
+** SQLITE_SOURCE_ID C preprocessor macro. Except if SQLite is built using
+** an edited copy of the amalgamation, then the last four characters of
+** the hash might be different from SQLITE_SOURCE_ID.
+*/
+/* SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; } */
+
+/* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
+** returns an integer equal to SQLITE_VERSION_NUMBER.
+*/
+SQLITE_API int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
+
+/* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
+** zero if and only if SQLite was compiled with mutexing code omitted due to
+** the SQLITE_THREADSAFE compile-time option being set to 0.
+*/
+SQLITE_API int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
+
+/*
+** When compiling the test fixture or with debugging enabled (on Win32),
+** this variable being set to non-zero will cause OSTRACE macros to emit
+** extra diagnostic information.
+*/
+#ifdef SQLITE_HAVE_OS_TRACE
+# ifndef SQLITE_DEBUG_OS_TRACE
+#   define SQLITE_DEBUG_OS_TRACE 0
+# endif
+  int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
+#endif
+
+#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
+/*
+** If the following function pointer is not NULL and if
+** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
+** I/O active are written using this function.  These messages
+** are intended for debugging activity only.
+*/
+SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
+#endif
+
+/*
+** If the following global variable points to a string which is the
+** name of a directory, then that directory will be used to store
+** temporary files.
+**
+** See also the "PRAGMA temp_store_directory" SQL command.
+*/
+SQLITE_API char *sqlite3_temp_directory = 0;
+
+/*
+** If the following global variable points to a string which is the
+** name of a directory, then that directory will be used to store
+** all database files specified with a relative pathname.
+**
+** See also the "PRAGMA data_store_directory" SQL command.
+*/
+SQLITE_API char *sqlite3_data_directory = 0;
+
+/*
+** Initialize SQLite.
+**
+** This routine must be called to initialize the memory allocation,
+** VFS, and mutex subsystems prior to doing any serious work with
+** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
+** this routine will be called automatically by key routines such as
+** sqlite3_open().
+**
+** This routine is a no-op except on its very first call for the process,
+** or for the first call after a call to sqlite3_shutdown.
+**
+** The first thread to call this routine runs the initialization to
+** completion.  If subsequent threads call this routine before the first
+** thread has finished the initialization process, then the subsequent
+** threads must block until the first thread finishes with the initialization.
+**
+** The first thread might call this routine recursively.  Recursive
+** calls to this routine should not block, of course.  Otherwise the
+** initialization process would never complete.
+**
+** Let X be the first thread to enter this routine.  Let Y be some other
+** thread.  Then while the initial invocation of this routine by X is
+** incomplete, it is required that:
+**
+**    *  Calls to this routine from Y must block until the outer-most
+**       call by X completes.
+**
+**    *  Recursive calls to this routine from thread X return immediately
+**       without blocking.
+*/
+SQLITE_API int sqlite3_initialize(void){
+  MUTEX_LOGIC( sqlite3_mutex *pMainMtx; )      /* The main static mutex */
+  int rc;                                      /* Result code */
+#ifdef SQLITE_EXTRA_INIT
+  int bRunExtraInit = 0;                       /* Extra initialization needed */
+#endif
+
+#ifdef SQLITE_OMIT_WSD
+  rc = sqlite3_wsd_init(4096, 24);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+#endif
+
+  /* If the following assert() fails on some obscure processor/compiler
+  ** combination, the work-around is to set the correct pointer
+  ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
+  assert( SQLITE_PTRSIZE==sizeof(char*) );
+
+  /* If SQLite is already completely initialized, then this call
+  ** to sqlite3_initialize() should be a no-op.  But the initialization
+  ** must be complete.  So isInit must not be set until the very end
+  ** of this routine.
+  */
+  if( sqlite3GlobalConfig.isInit ){
+    sqlite3MemoryBarrier();
+    return SQLITE_OK;
+  }
+
+  /* Make sure the mutex subsystem is initialized.  If unable to
+  ** initialize the mutex subsystem, return early with the error.
+  ** If the system is so sick that we are unable to allocate a mutex,
+  ** there is not much SQLite is going to be able to do.
+  **
+  ** The mutex subsystem must take care of serializing its own
+  ** initialization.
+  */
+  rc = sqlite3MutexInit();
+  if( rc ) return rc;
+
+  /* Initialize the malloc() system and the recursive pInitMutex mutex.
+  ** This operation is protected by the STATIC_MAIN mutex.  Note that
+  ** MutexAlloc() is called for a static mutex prior to initializing the
+  ** malloc subsystem - this implies that the allocation of a static
+  ** mutex must not require support from the malloc subsystem.
+  */
+  MUTEX_LOGIC( pMainMtx = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
+  sqlite3_mutex_enter(pMainMtx);
+  sqlite3GlobalConfig.isMutexInit = 1;
+  if( !sqlite3GlobalConfig.isMallocInit ){
+    rc = sqlite3MallocInit();
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3GlobalConfig.isMallocInit = 1;
+    if( !sqlite3GlobalConfig.pInitMutex ){
+      sqlite3GlobalConfig.pInitMutex =
+           sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
+      if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
+        rc = SQLITE_NOMEM_BKPT;
+      }
+    }
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3GlobalConfig.nRefInitMutex++;
+  }
+  sqlite3_mutex_leave(pMainMtx);
+
+  /* If rc is not SQLITE_OK at this point, then either the malloc
+  ** subsystem could not be initialized or the system failed to allocate
+  ** the pInitMutex mutex. Return an error in either case.  */
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* Do the rest of the initialization under the recursive mutex so
+  ** that we will be able to handle recursive calls into
+  ** sqlite3_initialize().  The recursive calls normally come through
+  ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
+  ** recursive calls might also be possible.
+  **
+  ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
+  ** to the xInit method, so the xInit method need not be threadsafe.
+  **
+  ** The following mutex is what serializes access to the appdef pcache xInit
+  ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
+  ** call to sqlite3PcacheInitialize().
+  */
+  sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
+  if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
+    sqlite3GlobalConfig.inProgress = 1;
+#ifdef SQLITE_ENABLE_SQLLOG
+    {
+      extern void sqlite3_init_sqllog(void);
+      sqlite3_init_sqllog();
+    }
+#endif
+    memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
+    sqlite3RegisterBuiltinFunctions();
+    if( sqlite3GlobalConfig.isPCacheInit==0 ){
+      rc = sqlite3PcacheInitialize();
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3GlobalConfig.isPCacheInit = 1;
+      rc = sqlite3OsInit();
+    }
+#ifndef SQLITE_OMIT_DESERIALIZE
+    if( rc==SQLITE_OK ){
+      rc = sqlite3MemdbInit();
+    }
+#endif
+    if( rc==SQLITE_OK ){
+      sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
+          sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
+      sqlite3MemoryBarrier();
+      sqlite3GlobalConfig.isInit = 1;
+#ifdef SQLITE_EXTRA_INIT
+      bRunExtraInit = 1;
+#endif
+    }
+    sqlite3GlobalConfig.inProgress = 0;
+  }
+  sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
+
+  /* Go back under the static mutex and clean up the recursive
+  ** mutex to prevent a resource leak.
+  */
+  sqlite3_mutex_enter(pMainMtx);
+  sqlite3GlobalConfig.nRefInitMutex--;
+  if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
+    assert( sqlite3GlobalConfig.nRefInitMutex==0 );
+    sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
+    sqlite3GlobalConfig.pInitMutex = 0;
+  }
+  sqlite3_mutex_leave(pMainMtx);
+
+  /* The following is just a sanity check to make sure SQLite has
+  ** been compiled correctly.  It is important to run this code, but
+  ** we don't want to run it too often and soak up CPU cycles for no
+  ** reason.  So we run it once during initialization.
+  */
+#ifndef NDEBUG
+#ifndef SQLITE_OMIT_FLOATING_POINT
+  /* This section of code's only "output" is via assert() statements. */
+  if( rc==SQLITE_OK ){
+    u64 x = (((u64)1)<<63)-1;
+    double y;
+    assert(sizeof(x)==8);
+    assert(sizeof(x)==sizeof(y));
+    memcpy(&y, &x, 8);
+    assert( sqlite3IsNaN(y) );
+  }
+#endif
+#endif
+
+  /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
+  ** compile-time option.
+  */
+#ifdef SQLITE_EXTRA_INIT
+  if( bRunExtraInit ){
+    int SQLITE_EXTRA_INIT(const char*);
+    rc = SQLITE_EXTRA_INIT(0);
+  }
+#endif
+  return rc;
+}
+
+/*
+** Undo the effects of sqlite3_initialize().  Must not be called while
+** there are outstanding database connections or memory allocations or
+** while any part of SQLite is otherwise in use in any thread.  This
+** routine is not threadsafe.  But it is safe to invoke this routine
+** on when SQLite is already shut down.  If SQLite is already shut down
+** when this routine is invoked, then this routine is a harmless no-op.
+*/
+SQLITE_API int sqlite3_shutdown(void){
+#ifdef SQLITE_OMIT_WSD
+  int rc = sqlite3_wsd_init(4096, 24);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+#endif
+
+  if( sqlite3GlobalConfig.isInit ){
+#ifdef SQLITE_EXTRA_SHUTDOWN
+    void SQLITE_EXTRA_SHUTDOWN(void);
+    SQLITE_EXTRA_SHUTDOWN();
+#endif
+    sqlite3_os_end();
+    sqlite3_reset_auto_extension();
+    sqlite3GlobalConfig.isInit = 0;
+  }
+  if( sqlite3GlobalConfig.isPCacheInit ){
+    sqlite3PcacheShutdown();
+    sqlite3GlobalConfig.isPCacheInit = 0;
+  }
+  if( sqlite3GlobalConfig.isMallocInit ){
+    sqlite3MallocEnd();
+    sqlite3GlobalConfig.isMallocInit = 0;
+
+#ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
+    /* The heap subsystem has now been shutdown and these values are supposed
+    ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
+    ** which would rely on that heap subsystem; therefore, make sure these
+    ** values cannot refer to heap memory that was just invalidated when the
+    ** heap subsystem was shutdown.  This is only done if the current call to
+    ** this function resulted in the heap subsystem actually being shutdown.
+    */
+    sqlite3_data_directory = 0;
+    sqlite3_temp_directory = 0;
+#endif
+  }
+  if( sqlite3GlobalConfig.isMutexInit ){
+    sqlite3MutexEnd();
+    sqlite3GlobalConfig.isMutexInit = 0;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** This API allows applications to modify the global configuration of
+** the SQLite library at run-time.
+**
+** This routine should only be called when there are no outstanding
+** database connections or memory allocations.  This routine is not
+** threadsafe.  Failure to heed these warnings can lead to unpredictable
+** behavior.
+*/
+SQLITE_API int sqlite3_config(int op, ...){
+  va_list ap;
+  int rc = SQLITE_OK;
+
+  /* sqlite3_config() normally returns SQLITE_MISUSE if it is invoked while
+  ** the SQLite library is in use.  Except, a few selected opcodes
+  ** are allowed.
+  */
+  if( sqlite3GlobalConfig.isInit ){
+    static const u64 mAnytimeConfigOption = 0
+       | MASKBIT64( SQLITE_CONFIG_LOG )
+       | MASKBIT64( SQLITE_CONFIG_PCACHE_HDRSZ )
+    ;
+    if( op<0 || op>63 || (MASKBIT64(op) & mAnytimeConfigOption)==0 ){
+      return SQLITE_MISUSE_BKPT;
+    }
+    testcase( op==SQLITE_CONFIG_LOG );
+    testcase( op==SQLITE_CONFIG_PCACHE_HDRSZ );
+  }
+
+  va_start(ap, op);
+  switch( op ){
+
+    /* Mutex configuration options are only available in a threadsafe
+    ** compile.
+    */
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
+    case SQLITE_CONFIG_SINGLETHREAD: {
+      /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
+      ** Single-thread. */
+      sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
+      sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
+      break;
+    }
+#endif
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
+    case SQLITE_CONFIG_MULTITHREAD: {
+      /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
+      ** Multi-thread. */
+      sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
+      sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
+      break;
+    }
+#endif
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
+    case SQLITE_CONFIG_SERIALIZED: {
+      /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
+      ** Serialized. */
+      sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
+      sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
+      break;
+    }
+#endif
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
+    case SQLITE_CONFIG_MUTEX: {
+      /* Specify an alternative mutex implementation */
+      sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
+      break;
+    }
+#endif
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
+    case SQLITE_CONFIG_GETMUTEX: {
+      /* Retrieve the current mutex implementation */
+      *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
+      break;
+    }
+#endif
+
+    case SQLITE_CONFIG_MALLOC: {
+      /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
+      ** single argument which is a pointer to an instance of the
+      ** sqlite3_mem_methods structure. The argument specifies alternative
+      ** low-level memory allocation routines to be used in place of the memory
+      ** allocation routines built into SQLite. */
+      sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
+      break;
+    }
+    case SQLITE_CONFIG_GETMALLOC: {
+      /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
+      ** single argument which is a pointer to an instance of the
+      ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
+      ** filled with the currently defined memory allocation routines. */
+      if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
+      *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
+      break;
+    }
+    case SQLITE_CONFIG_MEMSTATUS: {
+      assert( !sqlite3GlobalConfig.isInit );  /* Cannot change at runtime */
+      /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
+      ** single argument of type int, interpreted as a boolean, which enables
+      ** or disables the collection of memory allocation statistics. */
+      sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
+      break;
+    }
+    case SQLITE_CONFIG_SMALL_MALLOC: {
+      sqlite3GlobalConfig.bSmallMalloc = va_arg(ap, int);
+      break;
+    }
+    case SQLITE_CONFIG_PAGECACHE: {
+      /* EVIDENCE-OF: R-18761-36601 There are three arguments to
+      ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
+      ** the size of each page cache line (sz), and the number of cache lines
+      ** (N). */
+      sqlite3GlobalConfig.pPage = va_arg(ap, void*);
+      sqlite3GlobalConfig.szPage = va_arg(ap, int);
+      sqlite3GlobalConfig.nPage = va_arg(ap, int);
+      break;
+    }
+    case SQLITE_CONFIG_PCACHE_HDRSZ: {
+      /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
+      ** a single parameter which is a pointer to an integer and writes into
+      ** that integer the number of extra bytes per page required for each page
+      ** in SQLITE_CONFIG_PAGECACHE. */
+      *va_arg(ap, int*) =
+          sqlite3HeaderSizeBtree() +
+          sqlite3HeaderSizePcache() +
+          sqlite3HeaderSizePcache1();
+      break;
+    }
+
+    case SQLITE_CONFIG_PCACHE: {
+      /* no-op */
+      break;
+    }
+    case SQLITE_CONFIG_GETPCACHE: {
+      /* now an error */
+      rc = SQLITE_ERROR;
+      break;
+    }
+
+    case SQLITE_CONFIG_PCACHE2: {
+      /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
+      ** single argument which is a pointer to an sqlite3_pcache_methods2
+      ** object. This object specifies the interface to a custom page cache
+      ** implementation. */
+      sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
+      break;
+    }
+    case SQLITE_CONFIG_GETPCACHE2: {
+      /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
+      ** single argument which is a pointer to an sqlite3_pcache_methods2
+      ** object. SQLite copies of the current page cache implementation into
+      ** that object. */
+      if( sqlite3GlobalConfig.pcache2.xInit==0 ){
+        sqlite3PCacheSetDefault();
+      }
+      *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
+      break;
+    }
+
+/* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
+** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
+** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
+#if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
+    case SQLITE_CONFIG_HEAP: {
+      /* EVIDENCE-OF: R-19854-42126 There are three arguments to
+      ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
+      ** number of bytes in the memory buffer, and the minimum allocation size.
+      */
+      sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
+      sqlite3GlobalConfig.nHeap = va_arg(ap, int);
+      sqlite3GlobalConfig.mnReq = va_arg(ap, int);
+
+      if( sqlite3GlobalConfig.mnReq<1 ){
+        sqlite3GlobalConfig.mnReq = 1;
+      }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
+        /* cap min request size at 2^12 */
+        sqlite3GlobalConfig.mnReq = (1<<12);
+      }
+
+      if( sqlite3GlobalConfig.pHeap==0 ){
+        /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
+        ** is NULL, then SQLite reverts to using its default memory allocator
+        ** (the system malloc() implementation), undoing any prior invocation of
+        ** SQLITE_CONFIG_MALLOC.
+        **
+        ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
+        ** revert to its default implementation when sqlite3_initialize() is run
+        */
+        memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
+      }else{
+        /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
+        ** alternative memory allocator is engaged to handle all of SQLites
+        ** memory allocation needs. */
+#ifdef SQLITE_ENABLE_MEMSYS3
+        sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
+#endif
+#ifdef SQLITE_ENABLE_MEMSYS5
+        sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
+#endif
+      }
+      break;
+    }
+#endif
+
+    case SQLITE_CONFIG_LOOKASIDE: {
+      sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
+      sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
+      break;
+    }
+
+    /* Record a pointer to the logger function and its first argument.
+    ** The default is NULL.  Logging is disabled if the function pointer is
+    ** NULL.
+    */
+    case SQLITE_CONFIG_LOG: {
+      /* MSVC is picky about pulling func ptrs from va lists.
+      ** http://support.microsoft.com/kb/47961
+      ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
+      */
+      typedef void(*LOGFUNC_t)(void*,int,const char*);
+      LOGFUNC_t xLog = va_arg(ap, LOGFUNC_t);
+      void *pLogArg = va_arg(ap, void*);
+      AtomicStore(&sqlite3GlobalConfig.xLog, xLog);
+      AtomicStore(&sqlite3GlobalConfig.pLogArg, pLogArg);
+      break;
+    }
+
+    /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
+    ** can be changed at start-time using the
+    ** sqlite3_config(SQLITE_CONFIG_URI,1) or
+    ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
+    */
+    case SQLITE_CONFIG_URI: {
+      /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
+      ** argument of type int. If non-zero, then URI handling is globally
+      ** enabled. If the parameter is zero, then URI handling is globally
+      ** disabled. */
+      int bOpenUri = va_arg(ap, int);
+      AtomicStore(&sqlite3GlobalConfig.bOpenUri, bOpenUri);
+      break;
+    }
+
+    case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
+      /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
+      ** option takes a single integer argument which is interpreted as a
+      ** boolean in order to enable or disable the use of covering indices for
+      ** full table scans in the query optimizer. */
+      sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
+      break;
+    }
+
+#ifdef SQLITE_ENABLE_SQLLOG
+    case SQLITE_CONFIG_SQLLOG: {
+      typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
+      sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
+      sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
+      break;
+    }
+#endif
+
+    case SQLITE_CONFIG_MMAP_SIZE: {
+      /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
+      ** integer (sqlite3_int64) values that are the default mmap size limit
+      ** (the default setting for PRAGMA mmap_size) and the maximum allowed
+      ** mmap size limit. */
+      sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
+      sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
+      /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
+      ** negative, then that argument is changed to its compile-time default.
+      **
+      ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
+      ** silently truncated if necessary so that it does not exceed the
+      ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
+      ** compile-time option.
+      */
+      if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
+        mxMmap = SQLITE_MAX_MMAP_SIZE;
+      }
+      if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
+      if( szMmap>mxMmap) szMmap = mxMmap;
+      sqlite3GlobalConfig.mxMmap = mxMmap;
+      sqlite3GlobalConfig.szMmap = szMmap;
+      break;
+    }
+
+#if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
+    case SQLITE_CONFIG_WIN32_HEAPSIZE: {
+      /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
+      ** unsigned integer value that specifies the maximum size of the created
+      ** heap. */
+      sqlite3GlobalConfig.nHeap = va_arg(ap, int);
+      break;
+    }
+#endif
+
+    case SQLITE_CONFIG_PMASZ: {
+      sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
+      break;
+    }
+
+    case SQLITE_CONFIG_STMTJRNL_SPILL: {
+      sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
+      break;
+    }
+
+#ifdef SQLITE_ENABLE_SORTER_REFERENCES
+    case SQLITE_CONFIG_SORTERREF_SIZE: {
+      int iVal = va_arg(ap, int);
+      if( iVal<0 ){
+        iVal = SQLITE_DEFAULT_SORTERREF_SIZE;
+      }
+      sqlite3GlobalConfig.szSorterRef = (u32)iVal;
+      break;
+    }
+#endif /* SQLITE_ENABLE_SORTER_REFERENCES */
+
+#ifndef SQLITE_OMIT_DESERIALIZE
+    case SQLITE_CONFIG_MEMDB_MAXSIZE: {
+      sqlite3GlobalConfig.mxMemdbSize = va_arg(ap, sqlite3_int64);
+      break;
+    }
+#endif /* SQLITE_OMIT_DESERIALIZE */
+
+    case SQLITE_CONFIG_ROWID_IN_VIEW: {
+      int *pVal = va_arg(ap,int*);
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+      if( 0==*pVal ) sqlite3GlobalConfig.mNoVisibleRowid = TF_NoVisibleRowid;
+      if( 1==*pVal ) sqlite3GlobalConfig.mNoVisibleRowid = 0;
+      *pVal = (sqlite3GlobalConfig.mNoVisibleRowid==0);
+#else
+      *pVal = 0;
+#endif
+      break;
+    }
+
+    default: {
+      rc = SQLITE_ERROR;
+      break;
+    }
+  }
+  va_end(ap);
+  return rc;
+}
+
+/*
+** Set up the lookaside buffers for a database connection.
+** Return SQLITE_OK on success.
+** If lookaside is already active, return SQLITE_BUSY.
+**
+** The sz parameter is the number of bytes in each lookaside slot.
+** The cnt parameter is the number of slots.  If pStart is NULL the
+** space for the lookaside memory is obtained from sqlite3_malloc().
+** If pStart is not NULL then it is sz*cnt bytes of memory to use for
+** the lookaside memory.
+*/
+static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
+#ifndef SQLITE_OMIT_LOOKASIDE
+  void *pStart;
+  sqlite3_int64 szAlloc;
+  int nBig;   /* Number of full-size slots */
+  int nSm;    /* Number smaller LOOKASIDE_SMALL-byte slots */
+
+  if( sqlite3LookasideUsed(db,0)>0 ){
+    return SQLITE_BUSY;
+  }
+  /* Free any existing lookaside buffer for this handle before
+  ** allocating a new one so we don't have to have space for
+  ** both at the same time.
+  */
+  if( db->lookaside.bMalloced ){
+    sqlite3_free(db->lookaside.pStart);
+  }
+  /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
+  ** than a pointer to be useful.
+  */
+  sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
+  if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
+  if( sz>65528 ) sz = 65528;
+  if( cnt<0 ) cnt = 0;
+  szAlloc = (i64)sz*(i64)cnt;
+  if( sz==0 || cnt==0 ){
+    sz = 0;
+    pStart = 0;
+  }else if( pBuf==0 ){
+    sqlite3BeginBenignMalloc();
+    pStart = sqlite3Malloc( szAlloc );  /* IMP: R-61949-35727 */
+    sqlite3EndBenignMalloc();
+    if( pStart ) szAlloc = sqlite3MallocSize(pStart);
+  }else{
+    pStart = pBuf;
+  }
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+  if( sz>=LOOKASIDE_SMALL*3 ){
+    nBig = szAlloc/(3*LOOKASIDE_SMALL+sz);
+    nSm = (szAlloc - (i64)sz*(i64)nBig)/LOOKASIDE_SMALL;
+  }else if( sz>=LOOKASIDE_SMALL*2 ){
+    nBig = szAlloc/(LOOKASIDE_SMALL+sz);
+    nSm = (szAlloc - (i64)sz*(i64)nBig)/LOOKASIDE_SMALL;
+  }else
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+  if( sz>0 ){
+    nBig = szAlloc/sz;
+    nSm = 0;
+  }else{
+    nBig = nSm = 0;
+  }
+  db->lookaside.pStart = pStart;
+  db->lookaside.pInit = 0;
+  db->lookaside.pFree = 0;
+  db->lookaside.sz = (u16)sz;
+  db->lookaside.szTrue = (u16)sz;
+  if( pStart ){
+    int i;
+    LookasideSlot *p;
+    assert( sz > (int)sizeof(LookasideSlot*) );
+    p = (LookasideSlot*)pStart;
+    for(i=0; i<nBig; i++){
+      p->pNext = db->lookaside.pInit;
+      db->lookaside.pInit = p;
+      p = (LookasideSlot*)&((u8*)p)[sz];
+    }
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+    db->lookaside.pSmallInit = 0;
+    db->lookaside.pSmallFree = 0;
+    db->lookaside.pMiddle = p;
+    for(i=0; i<nSm; i++){
+      p->pNext = db->lookaside.pSmallInit;
+      db->lookaside.pSmallInit = p;
+      p = (LookasideSlot*)&((u8*)p)[LOOKASIDE_SMALL];
+    }
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+    assert( ((uptr)p)<=szAlloc + (uptr)pStart );
+    db->lookaside.pEnd = p;
+    db->lookaside.bDisable = 0;
+    db->lookaside.bMalloced = pBuf==0 ?1:0;
+    db->lookaside.nSlot = nBig+nSm;
+  }else{
+    db->lookaside.pStart = 0;
+#ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
+    db->lookaside.pSmallInit = 0;
+    db->lookaside.pSmallFree = 0;
+    db->lookaside.pMiddle = 0;
+#endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
+    db->lookaside.pEnd = 0;
+    db->lookaside.bDisable = 1;
+    db->lookaside.sz = 0;
+    db->lookaside.bMalloced = 0;
+    db->lookaside.nSlot = 0;
+  }
+  db->lookaside.pTrueEnd = db->lookaside.pEnd;
+  assert( sqlite3LookasideUsed(db,0)==0 );
+#endif /* SQLITE_OMIT_LOOKASIDE */
+  return SQLITE_OK;
+}
+
+/*
+** Return the mutex associated with a database connection.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->mutex;
+}
+
+/*
+** Free up as much memory as we can from the given database
+** connection.
+*/
+SQLITE_API int sqlite3_db_release_memory(sqlite3 *db){
+  int i;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  for(i=0; i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      Pager *pPager = sqlite3BtreePager(pBt);
+      sqlite3PagerShrink(pPager);
+    }
+  }
+  sqlite3BtreeLeaveAll(db);
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Flush any dirty pages in the pager-cache for any attached database
+** to disk.
+*/
+SQLITE_API int sqlite3_db_cacheflush(sqlite3 *db){
+  int i;
+  int rc = SQLITE_OK;
+  int bSeenBusy = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt && sqlite3BtreeTxnState(pBt)==SQLITE_TXN_WRITE ){
+      Pager *pPager = sqlite3BtreePager(pBt);
+      rc = sqlite3PagerFlush(pPager);
+      if( rc==SQLITE_BUSY ){
+        bSeenBusy = 1;
+        rc = SQLITE_OK;
+      }
+    }
+  }
+  sqlite3BtreeLeaveAll(db);
+  sqlite3_mutex_leave(db->mutex);
+  return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
+}
+
+/*
+** Configuration settings for an individual database connection
+*/
+SQLITE_API int sqlite3_db_config(sqlite3 *db, int op, ...){
+  va_list ap;
+  int rc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  va_start(ap, op);
+  switch( op ){
+    case SQLITE_DBCONFIG_MAINDBNAME: {
+      /* IMP: R-06824-28531 */
+      /* IMP: R-36257-52125 */
+      db->aDb[0].zDbSName = va_arg(ap,char*);
+      rc = SQLITE_OK;
+      break;
+    }
+    case SQLITE_DBCONFIG_LOOKASIDE: {
+      void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
+      int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
+      int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
+      rc = setupLookaside(db, pBuf, sz, cnt);
+      break;
+    }
+    default: {
+      static const struct {
+        int op;      /* The opcode */
+        u64 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
+      } aFlagOp[] = {
+        { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
+        { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
+        { SQLITE_DBCONFIG_ENABLE_VIEW,           SQLITE_EnableView     },
+        { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
+        { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
+        { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
+        { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
+        { SQLITE_DBCONFIG_TRIGGER_EQP,           SQLITE_TriggerEQP     },
+        { SQLITE_DBCONFIG_RESET_DATABASE,        SQLITE_ResetDatabase  },
+        { SQLITE_DBCONFIG_DEFENSIVE,             SQLITE_Defensive      },
+        { SQLITE_DBCONFIG_WRITABLE_SCHEMA,       SQLITE_WriteSchema|
+                                                 SQLITE_NoSchemaError  },
+        { SQLITE_DBCONFIG_LEGACY_ALTER_TABLE,    SQLITE_LegacyAlter    },
+        { SQLITE_DBCONFIG_DQS_DDL,               SQLITE_DqsDDL         },
+        { SQLITE_DBCONFIG_DQS_DML,               SQLITE_DqsDML         },
+        { SQLITE_DBCONFIG_LEGACY_FILE_FORMAT,    SQLITE_LegacyFileFmt  },
+        { SQLITE_DBCONFIG_TRUSTED_SCHEMA,        SQLITE_TrustedSchema  },
+        { SQLITE_DBCONFIG_STMT_SCANSTATUS,       SQLITE_StmtScanStatus },
+        { SQLITE_DBCONFIG_REVERSE_SCANORDER,     SQLITE_ReverseOrder   },
+        { SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE,  SQLITE_AttachCreate   },
+        { SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE,   SQLITE_AttachWrite    },
+        { SQLITE_DBCONFIG_ENABLE_COMMENTS,       SQLITE_Comments       },
+      };
+      unsigned int i;
+      rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
+      for(i=0; i<ArraySize(aFlagOp); i++){
+        if( aFlagOp[i].op==op ){
+          int onoff = va_arg(ap, int);
+          int *pRes = va_arg(ap, int*);
+          u64 oldFlags = db->flags;
+          if( onoff>0 ){
+            db->flags |= aFlagOp[i].mask;
+          }else if( onoff==0 ){
+            db->flags &= ~(u64)aFlagOp[i].mask;
+          }
+          if( oldFlags!=db->flags ){
+            sqlite3ExpirePreparedStatements(db, 0);
+          }
+          if( pRes ){
+            *pRes = (db->flags & aFlagOp[i].mask)!=0;
+          }
+          rc = SQLITE_OK;
+          break;
+        }
+      }
+      break;
+    }
+  }
+  va_end(ap);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** This is the default collating function named "BINARY" which is always
+** available.
+*/
+static int binCollFunc(
+  void *NotUsed,
+  int nKey1, const void *pKey1,
+  int nKey2, const void *pKey2
+){
+  int rc, n;
+  UNUSED_PARAMETER(NotUsed);
+  n = nKey1<nKey2 ? nKey1 : nKey2;
+  /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
+  ** strings byte by byte using the memcmp() function from the standard C
+  ** library. */
+  assert( pKey1 && pKey2 );
+  rc = memcmp(pKey1, pKey2, n);
+  if( rc==0 ){
+    rc = nKey1 - nKey2;
+  }
+  return rc;
+}
+
+/*
+** This is the collating function named "RTRIM" which is always
+** available.  Ignore trailing spaces.
+*/
+static int rtrimCollFunc(
+  void *pUser,
+  int nKey1, const void *pKey1,
+  int nKey2, const void *pKey2
+){
+  const u8 *pK1 = (const u8*)pKey1;
+  const u8 *pK2 = (const u8*)pKey2;
+  while( nKey1 && pK1[nKey1-1]==' ' ) nKey1--;
+  while( nKey2 && pK2[nKey2-1]==' ' ) nKey2--;
+  return binCollFunc(pUser, nKey1, pKey1, nKey2, pKey2);
+}
+
+/*
+** Return true if CollSeq is the default built-in BINARY.
+*/
+SQLITE_PRIVATE int sqlite3IsBinary(const CollSeq *p){
+  assert( p==0 || p->xCmp!=binCollFunc || strcmp(p->zName,"BINARY")==0 );
+  return p==0 || p->xCmp==binCollFunc;
+}
+
+/*
+** Another built-in collating sequence: NOCASE.
+**
+** This collating sequence is intended to be used for "case independent
+** comparison". SQLite's knowledge of upper and lower case equivalents
+** extends only to the 26 characters used in the English language.
+**
+** At the moment there is only a UTF-8 implementation.
+*/
+static int nocaseCollatingFunc(
+  void *NotUsed,
+  int nKey1, const void *pKey1,
+  int nKey2, const void *pKey2
+){
+  int r = sqlite3StrNICmp(
+      (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
+  UNUSED_PARAMETER(NotUsed);
+  if( 0==r ){
+    r = nKey1-nKey2;
+  }
+  return r;
+}
+
+/*
+** Return the ROWID of the most recent insert
+*/
+SQLITE_API sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->lastRowid;
+}
+
+/*
+** Set the value returned by the sqlite3_last_insert_rowid() API function.
+*/
+SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->lastRowid = iRowid;
+  sqlite3_mutex_leave(db->mutex);
+}
+
+/*
+** Return the number of changes in the most recent call to sqlite3_exec().
+*/
+SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->nChange;
+}
+SQLITE_API int sqlite3_changes(sqlite3 *db){
+  return (int)sqlite3_changes64(db);
+}
+
+/*
+** Return the number of changes since the database handle was opened.
+*/
+SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->nTotalChange;
+}
+SQLITE_API int sqlite3_total_changes(sqlite3 *db){
+  return (int)sqlite3_total_changes64(db);
+}
+
+/*
+** Close all open savepoints. This function only manipulates fields of the
+** database handle object, it does not close any savepoints that may be open
+** at the b-tree/pager level.
+*/
+SQLITE_PRIVATE void sqlite3CloseSavepoints(sqlite3 *db){
+  while( db->pSavepoint ){
+    Savepoint *pTmp = db->pSavepoint;
+    db->pSavepoint = pTmp->pNext;
+    sqlite3DbFree(db, pTmp);
+  }
+  db->nSavepoint = 0;
+  db->nStatement = 0;
+  db->isTransactionSavepoint = 0;
+}
+
+/*
+** Invoke the destructor function associated with FuncDef p, if any. Except,
+** if this is not the last copy of the function, do not invoke it. Multiple
+** copies of a single function are created when create_function() is called
+** with SQLITE_ANY as the encoding.
+*/
+static void functionDestroy(sqlite3 *db, FuncDef *p){
+  FuncDestructor *pDestructor;
+  assert( (p->funcFlags & SQLITE_FUNC_BUILTIN)==0 );
+  pDestructor = p->u.pDestructor;
+  if( pDestructor ){
+    pDestructor->nRef--;
+    if( pDestructor->nRef==0 ){
+      pDestructor->xDestroy(pDestructor->pUserData);
+      sqlite3DbFree(db, pDestructor);
+    }
+  }
+}
+
+/*
+** Disconnect all sqlite3_vtab objects that belong to database connection
+** db. This is called when db is being closed.
+*/
+static void disconnectAllVtab(sqlite3 *db){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  int i;
+  HashElem *p;
+  sqlite3BtreeEnterAll(db);
+  for(i=0; i<db->nDb; i++){
+    Schema *pSchema = db->aDb[i].pSchema;
+    if( pSchema ){
+      for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
+        Table *pTab = (Table *)sqliteHashData(p);
+        if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
+      }
+    }
+  }
+  for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
+    Module *pMod = (Module *)sqliteHashData(p);
+    if( pMod->pEpoTab ){
+      sqlite3VtabDisconnect(db, pMod->pEpoTab);
+    }
+  }
+  sqlite3VtabUnlockList(db);
+  sqlite3BtreeLeaveAll(db);
+#else
+  UNUSED_PARAMETER(db);
+#endif
+}
+
+/*
+** Return TRUE if database connection db has unfinalized prepared
+** statements or unfinished sqlite3_backup objects.
+*/
+static int connectionIsBusy(sqlite3 *db){
+  int j;
+  assert( sqlite3_mutex_held(db->mutex) );
+  if( db->pVdbe ) return 1;
+  for(j=0; j<db->nDb; j++){
+    Btree *pBt = db->aDb[j].pBt;
+    if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Close an existing SQLite database
+*/
+static int sqlite3Close(sqlite3 *db, int forceZombie){
+  if( !db ){
+    /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
+    ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
+    return SQLITE_OK;
+  }
+  if( !sqlite3SafetyCheckSickOrOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  sqlite3_mutex_enter(db->mutex);
+  if( db->mTrace & SQLITE_TRACE_CLOSE ){
+    db->trace.xV2(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
+  }
+
+  /* Force xDisconnect calls on all virtual tables */
+  disconnectAllVtab(db);
+
+  /* If a transaction is open, the disconnectAllVtab() call above
+  ** will not have called the xDisconnect() method on any virtual
+  ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
+  ** call will do so. We need to do this before the check for active
+  ** SQL statements below, as the v-table implementation may be storing
+  ** some prepared statements internally.
+  */
+  sqlite3VtabRollback(db);
+
+  /* Legacy behavior (sqlite3_close() behavior) is to return
+  ** SQLITE_BUSY if the connection can not be closed immediately.
+  */
+  if( !forceZombie && connectionIsBusy(db) ){
+    sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
+       "statements or unfinished backups");
+    sqlite3_mutex_leave(db->mutex);
+    return SQLITE_BUSY;
+  }
+
+#ifdef SQLITE_ENABLE_SQLLOG
+  if( sqlite3GlobalConfig.xSqllog ){
+    /* Closing the handle. Fourth parameter is passed the value 2. */
+    sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
+  }
+#endif
+
+  while( db->pDbData ){
+    DbClientData *p = db->pDbData;
+    db->pDbData = p->pNext;
+    assert( p->pData!=0 );
+    if( p->xDestructor ) p->xDestructor(p->pData);
+    sqlite3_free(p);
+  }
+
+  /* Convert the connection into a zombie and then close it.
+  */
+  db->eOpenState = SQLITE_STATE_ZOMBIE;
+  sqlite3LeaveMutexAndCloseZombie(db);
+  return SQLITE_OK;
+}
+
+/*
+** Return the transaction state for a single databse, or the maximum
+** transaction state over all attached databases if zSchema is null.
+*/
+SQLITE_API int sqlite3_txn_state(sqlite3 *db, const char *zSchema){
+  int iDb, nDb;
+  int iTxn = -1;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return -1;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( zSchema ){
+    nDb = iDb = sqlite3FindDbName(db, zSchema);
+    if( iDb<0 ) nDb--;
+  }else{
+    iDb = 0;
+    nDb = db->nDb-1;
+  }
+  for(; iDb<=nDb; iDb++){
+    Btree *pBt = db->aDb[iDb].pBt;
+    int x = pBt!=0 ? sqlite3BtreeTxnState(pBt) : SQLITE_TXN_NONE;
+    if( x>iTxn ) iTxn = x;
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return iTxn;
+}
+
+/*
+** Two variations on the public interface for closing a database
+** connection. The sqlite3_close() version returns SQLITE_BUSY and
+** leaves the connection open if there are unfinalized prepared
+** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
+** version forces the connection to become a zombie if there are
+** unclosed resources, and arranges for deallocation when the last
+** prepare statement or sqlite3_backup closes.
+*/
+SQLITE_API int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
+SQLITE_API int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
+
+
+/*
+** Close the mutex on database connection db.
+**
+** Furthermore, if database connection db is a zombie (meaning that there
+** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
+** every sqlite3_stmt has now been finalized and every sqlite3_backup has
+** finished, then free all resources.
+*/
+SQLITE_PRIVATE void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
+  HashElem *i;                    /* Hash table iterator */
+  int j;
+
+  /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
+  ** or if the connection has not yet been closed by sqlite3_close_v2(),
+  ** then just leave the mutex and return.
+  */
+  if( db->eOpenState!=SQLITE_STATE_ZOMBIE || connectionIsBusy(db) ){
+    sqlite3_mutex_leave(db->mutex);
+    return;
+  }
+
+  /* If we reach this point, it means that the database connection has
+  ** closed all sqlite3_stmt and sqlite3_backup objects and has been
+  ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
+  ** go ahead and free all resources.
+  */
+
+  /* If a transaction is open, roll it back. This also ensures that if
+  ** any database schemas have been modified by an uncommitted transaction
+  ** they are reset. And that the required b-tree mutex is held to make
+  ** the pager rollback and schema reset an atomic operation. */
+  sqlite3RollbackAll(db, SQLITE_OK);
+
+  /* Free any outstanding Savepoint structures. */
+  sqlite3CloseSavepoints(db);
+
+  /* Close all database connections */
+  for(j=0; j<db->nDb; j++){
+    struct Db *pDb = &db->aDb[j];
+    if( pDb->pBt ){
+      sqlite3BtreeClose(pDb->pBt);
+      pDb->pBt = 0;
+      if( j!=1 ){
+        pDb->pSchema = 0;
+      }
+    }
+  }
+  /* Clear the TEMP schema separately and last */
+  if( db->aDb[1].pSchema ){
+    sqlite3SchemaClear(db->aDb[1].pSchema);
+  }
+  sqlite3VtabUnlockList(db);
+
+  /* Free up the array of auxiliary databases */
+  sqlite3CollapseDatabaseArray(db);
+  assert( db->nDb<=2 );
+  assert( db->aDb==db->aDbStatic );
+
+  /* Tell the code in notify.c that the connection no longer holds any
+  ** locks and does not require any further unlock-notify callbacks.
+  */
+  sqlite3ConnectionClosed(db);
+
+  for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
+    FuncDef *pNext, *p;
+    p = sqliteHashData(i);
+    do{
+      functionDestroy(db, p);
+      pNext = p->pNext;
+      sqlite3DbFree(db, p);
+      p = pNext;
+    }while( p );
+  }
+  sqlite3HashClear(&db->aFunc);
+  for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
+    CollSeq *pColl = (CollSeq *)sqliteHashData(i);
+    /* Invoke any destructors registered for collation sequence user data. */
+    for(j=0; j<3; j++){
+      if( pColl[j].xDel ){
+        pColl[j].xDel(pColl[j].pUser);
+      }
+    }
+    sqlite3DbFree(db, pColl);
+  }
+  sqlite3HashClear(&db->aCollSeq);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
+    Module *pMod = (Module *)sqliteHashData(i);
+    sqlite3VtabEponymousTableClear(db, pMod);
+    sqlite3VtabModuleUnref(db, pMod);
+  }
+  sqlite3HashClear(&db->aModule);
+#endif
+
+  sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
+  sqlite3ValueFree(db->pErr);
+  sqlite3CloseExtensions(db);
+
+  db->eOpenState = SQLITE_STATE_ERROR;
+
+  /* The temp-database schema is allocated differently from the other schema
+  ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
+  ** So it needs to be freed here. Todo: Why not roll the temp schema into
+  ** the same sqliteMalloc() as the one that allocates the database
+  ** structure?
+  */
+  sqlite3DbFree(db, db->aDb[1].pSchema);
+  if( db->xAutovacDestr ){
+    db->xAutovacDestr(db->pAutovacPagesArg);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  db->eOpenState = SQLITE_STATE_CLOSED;
+  sqlite3_mutex_free(db->mutex);
+  assert( sqlite3LookasideUsed(db,0)==0 );
+  if( db->lookaside.bMalloced ){
+    sqlite3_free(db->lookaside.pStart);
+  }
+  sqlite3_free(db);
+}
+
+/*
+** Rollback all database files.  If tripCode is not SQLITE_OK, then
+** any write cursors are invalidated ("tripped" - as in "tripping a circuit
+** breaker") and made to return tripCode if there are any further
+** attempts to use that cursor.  Read cursors remain open and valid
+** but are "saved" in case the table pages are moved around.
+*/
+SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3 *db, int tripCode){
+  int i;
+  int inTrans = 0;
+  int schemaChange;
+  assert( sqlite3_mutex_held(db->mutex) );
+  sqlite3BeginBenignMalloc();
+
+  /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
+  ** This is important in case the transaction being rolled back has
+  ** modified the database schema. If the b-tree mutexes are not taken
+  ** here, then another shared-cache connection might sneak in between
+  ** the database rollback and schema reset, which can cause false
+  ** corruption reports in some cases.  */
+  sqlite3BtreeEnterAll(db);
+  schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;
+
+  for(i=0; i<db->nDb; i++){
+    Btree *p = db->aDb[i].pBt;
+    if( p ){
+      if( sqlite3BtreeTxnState(p)==SQLITE_TXN_WRITE ){
+        inTrans = 1;
+      }
+      sqlite3BtreeRollback(p, tripCode, !schemaChange);
+    }
+  }
+  sqlite3VtabRollback(db);
+  sqlite3EndBenignMalloc();
+
+  if( schemaChange ){
+    sqlite3ExpirePreparedStatements(db, 0);
+    sqlite3ResetAllSchemasOfConnection(db);
+  }
+  sqlite3BtreeLeaveAll(db);
+
+  /* Any deferred constraint violations have now been resolved. */
+  db->nDeferredCons = 0;
+  db->nDeferredImmCons = 0;
+  db->flags &= ~(u64)(SQLITE_DeferFKs|SQLITE_CorruptRdOnly);
+
+  /* If one has been configured, invoke the rollback-hook callback */
+  if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
+    db->xRollbackCallback(db->pRollbackArg);
+  }
+}
+
+/*
+** Return a static string containing the name corresponding to the error code
+** specified in the argument.
+*/
+#if defined(SQLITE_NEED_ERR_NAME)
+SQLITE_PRIVATE const char *sqlite3ErrName(int rc){
+  const char *zName = 0;
+  int i, origRc = rc;
+  for(i=0; i<2 && zName==0; i++, rc &= 0xff){
+    switch( rc ){
+      case SQLITE_OK:                 zName = "SQLITE_OK";                break;
+      case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
+      case SQLITE_ERROR_SNAPSHOT:     zName = "SQLITE_ERROR_SNAPSHOT";    break;
+      case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
+      case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
+      case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
+      case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
+      case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
+      case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
+      case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
+      case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
+      case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
+      case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
+      case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
+      case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
+      case SQLITE_READONLY_CANTINIT:  zName = "SQLITE_READONLY_CANTINIT"; break;
+      case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
+      case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
+      case SQLITE_READONLY_DIRECTORY: zName = "SQLITE_READONLY_DIRECTORY";break;
+      case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
+      case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
+      case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
+      case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
+      case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
+      case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
+      case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
+      case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
+      case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
+      case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
+      case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
+      case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
+      case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
+      case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
+      case SQLITE_IOERR_CHECKRESERVEDLOCK:
+                                zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
+      case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
+      case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
+      case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
+      case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
+      case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
+      case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
+      case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
+      case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
+      case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
+      case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
+      case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
+      case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
+      case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
+      case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
+      case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
+      case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
+      case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
+      case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
+      case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
+      case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
+      case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
+      case SQLITE_CANTOPEN_SYMLINK:   zName = "SQLITE_CANTOPEN_SYMLINK";  break;
+      case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
+      case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
+      case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
+      case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
+      case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
+      case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
+      case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
+      case SQLITE_CONSTRAINT_FOREIGNKEY:
+                                zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
+      case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
+      case SQLITE_CONSTRAINT_PRIMARYKEY:
+                                zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
+      case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
+      case SQLITE_CONSTRAINT_COMMITHOOK:
+                                zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
+      case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
+      case SQLITE_CONSTRAINT_FUNCTION:
+                                zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
+      case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
+      case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
+      case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
+      case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
+      case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
+      case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
+      case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
+      case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
+      case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
+      case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
+      case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
+      case SQLITE_NOTICE_RECOVER_ROLLBACK:
+                                zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
+      case SQLITE_NOTICE_RBU:         zName = "SQLITE_NOTICE_RBU"; break;
+      case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
+      case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
+      case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
+    }
+  }
+  if( zName==0 ){
+    static char zBuf[50];
+    sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
+    zName = zBuf;
+  }
+  return zName;
+}
+#endif
+
+/*
+** Return a static string that describes the kind of error specified in the
+** argument.
+*/
+SQLITE_PRIVATE const char *sqlite3ErrStr(int rc){
+  static const char* const aMsg[] = {
+    /* SQLITE_OK          */ "not an error",
+    /* SQLITE_ERROR       */ "SQL logic error",
+    /* SQLITE_INTERNAL    */ 0,
+    /* SQLITE_PERM        */ "access permission denied",
+    /* SQLITE_ABORT       */ "query aborted",
+    /* SQLITE_BUSY        */ "database is locked",
+    /* SQLITE_LOCKED      */ "database table is locked",
+    /* SQLITE_NOMEM       */ "out of memory",
+    /* SQLITE_READONLY    */ "attempt to write a readonly database",
+    /* SQLITE_INTERRUPT   */ "interrupted",
+    /* SQLITE_IOERR       */ "disk I/O error",
+    /* SQLITE_CORRUPT     */ "database disk image is malformed",
+    /* SQLITE_NOTFOUND    */ "unknown operation",
+    /* SQLITE_FULL        */ "database or disk is full",
+    /* SQLITE_CANTOPEN    */ "unable to open database file",
+    /* SQLITE_PROTOCOL    */ "locking protocol",
+    /* SQLITE_EMPTY       */ 0,
+    /* SQLITE_SCHEMA      */ "database schema has changed",
+    /* SQLITE_TOOBIG      */ "string or blob too big",
+    /* SQLITE_CONSTRAINT  */ "constraint failed",
+    /* SQLITE_MISMATCH    */ "datatype mismatch",
+    /* SQLITE_MISUSE      */ "bad parameter or other API misuse",
+#ifdef SQLITE_DISABLE_LFS
+    /* SQLITE_NOLFS       */ "large file support is disabled",
+#else
+    /* SQLITE_NOLFS       */ 0,
+#endif
+    /* SQLITE_AUTH        */ "authorization denied",
+    /* SQLITE_FORMAT      */ 0,
+    /* SQLITE_RANGE       */ "column index out of range",
+    /* SQLITE_NOTADB      */ "file is not a database",
+    /* SQLITE_NOTICE      */ "notification message",
+    /* SQLITE_WARNING     */ "warning message",
+  };
+  const char *zErr = "unknown error";
+  switch( rc ){
+    case SQLITE_ABORT_ROLLBACK: {
+      zErr = "abort due to ROLLBACK";
+      break;
+    }
+    case SQLITE_ROW: {
+      zErr = "another row available";
+      break;
+    }
+    case SQLITE_DONE: {
+      zErr = "no more rows available";
+      break;
+    }
+    default: {
+      rc &= 0xff;
+      if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
+        zErr = aMsg[rc];
+      }
+      break;
+    }
+  }
+  return zErr;
+}
+
+/*
+** This routine implements a busy callback that sleeps and tries
+** again until a timeout value is reached.  The timeout value is
+** an integer number of milliseconds passed in as the first
+** argument.
+**
+** Return non-zero to retry the lock.  Return zero to stop trying
+** and cause SQLite to return SQLITE_BUSY.
+*/
+static int sqliteDefaultBusyCallback(
+  void *ptr,               /* Database connection */
+  int count                /* Number of times table has been busy */
+){
+#if SQLITE_OS_WIN || !defined(HAVE_NANOSLEEP) || HAVE_NANOSLEEP
+  /* This case is for systems that have support for sleeping for fractions of
+  ** a second.  Examples:  All windows systems, unix systems with nanosleep() */
+  static const u8 delays[] =
+     { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
+  static const u8 totals[] =
+     { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
+# define NDELAY ArraySize(delays)
+  sqlite3 *db = (sqlite3 *)ptr;
+  int tmout = db->busyTimeout;
+  int delay, prior;
+
+  assert( count>=0 );
+  if( count < NDELAY ){
+    delay = delays[count];
+    prior = totals[count];
+  }else{
+    delay = delays[NDELAY-1];
+    prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
+  }
+  if( prior + delay > tmout ){
+    delay = tmout - prior;
+    if( delay<=0 ) return 0;
+  }
+  sqlite3OsSleep(db->pVfs, delay*1000);
+  return 1;
+#else
+  /* This case for unix systems that lack usleep() support.  Sleeping
+  ** must be done in increments of whole seconds */
+  sqlite3 *db = (sqlite3 *)ptr;
+  int tmout = ((sqlite3 *)ptr)->busyTimeout;
+  if( (count+1)*1000 > tmout ){
+    return 0;
+  }
+  sqlite3OsSleep(db->pVfs, 1000000);
+  return 1;
+#endif
+}
+
+/*
+** Invoke the given busy handler.
+**
+** This routine is called when an operation failed to acquire a
+** lock on VFS file pFile.
+**
+** If this routine returns non-zero, the lock is retried.  If it
+** returns 0, the operation aborts with an SQLITE_BUSY error.
+*/
+SQLITE_PRIVATE int sqlite3InvokeBusyHandler(BusyHandler *p){
+  int rc;
+  if( p->xBusyHandler==0 || p->nBusy<0 ) return 0;
+  rc = p->xBusyHandler(p->pBusyArg, p->nBusy);
+  if( rc==0 ){
+    p->nBusy = -1;
+  }else{
+    p->nBusy++;
+  }
+  return rc;
+}
+
+/*
+** This routine sets the busy callback for an Sqlite database to the
+** given callback function with the given argument.
+*/
+SQLITE_API int sqlite3_busy_handler(
+  sqlite3 *db,
+  int (*xBusy)(void*,int),
+  void *pArg
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->busyHandler.xBusyHandler = xBusy;
+  db->busyHandler.pBusyArg = pArg;
+  db->busyHandler.nBusy = 0;
+  db->busyTimeout = 0;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
+/*
+** This routine sets the progress callback for an Sqlite database to the
+** given callback function with the given argument. The progress callback will
+** be invoked every nOps opcodes.
+*/
+SQLITE_API void sqlite3_progress_handler(
+  sqlite3 *db,
+  int nOps,
+  int (*xProgress)(void*),
+  void *pArg
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( nOps>0 ){
+    db->xProgress = xProgress;
+    db->nProgressOps = (unsigned)nOps;
+    db->pProgressArg = pArg;
+  }else{
+    db->xProgress = 0;
+    db->nProgressOps = 0;
+    db->pProgressArg = 0;
+  }
+  sqlite3_mutex_leave(db->mutex);
+}
+#endif
+
+
+/*
+** This routine installs a default busy handler that waits for the
+** specified number of milliseconds before returning 0.
+*/
+SQLITE_API int sqlite3_busy_timeout(sqlite3 *db, int ms){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  if( ms>0 ){
+    sqlite3_busy_handler(db, (int(*)(void*,int))sqliteDefaultBusyCallback,
+                             (void*)db);
+    db->busyTimeout = ms;
+  }else{
+    sqlite3_busy_handler(db, 0, 0);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Cause any pending operation to stop at its earliest opportunity.
+*/
+SQLITE_API void sqlite3_interrupt(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db)
+   && (db==0 || db->eOpenState!=SQLITE_STATE_ZOMBIE)
+  ){
+    (void)SQLITE_MISUSE_BKPT;
+    return;
+  }
+#endif
+  AtomicStore(&db->u1.isInterrupted, 1);
+}
+
+/*
+** Return true or false depending on whether or not an interrupt is
+** pending on connection db.
+*/
+SQLITE_API int sqlite3_is_interrupted(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db)
+   && (db==0 || db->eOpenState!=SQLITE_STATE_ZOMBIE)
+  ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return AtomicLoad(&db->u1.isInterrupted)!=0;
+}
+
+/*
+** This function is exactly the same as sqlite3_create_function(), except
+** that it is designed to be called by internal code. The difference is
+** that if a malloc() fails in sqlite3_create_function(), an error code
+** is returned and the mallocFailed flag cleared.
+*/
+SQLITE_PRIVATE int sqlite3CreateFunc(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int enc,
+  void *pUserData,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
+  FuncDestructor *pDestructor
+){
+  FuncDef *p;
+  int extraFlags;
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( xValue==0 || xSFunc==0 );
+  if( zFunctionName==0                /* Must have a valid name */
+   || (xSFunc!=0 && xFinal!=0)        /* Not both xSFunc and xFinal */
+   || ((xFinal==0)!=(xStep==0))       /* Both or neither of xFinal and xStep */
+   || ((xValue==0)!=(xInverse==0))    /* Both or neither of xValue, xInverse */
+   || (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG)
+   || (255<sqlite3Strlen30(zFunctionName))
+  ){
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
+  assert( SQLITE_FUNC_DIRECT==SQLITE_DIRECTONLY );
+  extraFlags = enc &  (SQLITE_DETERMINISTIC|SQLITE_DIRECTONLY|
+                       SQLITE_SUBTYPE|SQLITE_INNOCUOUS|
+                       SQLITE_RESULT_SUBTYPE|SQLITE_SELFORDER1);
+  enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
+
+  /* The SQLITE_INNOCUOUS flag is the same bit as SQLITE_FUNC_UNSAFE.  But
+  ** the meaning is inverted.  So flip the bit. */
+  assert( SQLITE_FUNC_UNSAFE==SQLITE_INNOCUOUS );
+  extraFlags ^= SQLITE_FUNC_UNSAFE;  /* tag-20230109-1 */
+
+
+#ifndef SQLITE_OMIT_UTF16
+  /* If SQLITE_UTF16 is specified as the encoding type, transform this
+  ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
+  ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
+  **
+  ** If SQLITE_ANY is specified, add three versions of the function
+  ** to the hash table.
+  */
+  switch( enc ){
+    case SQLITE_UTF16:
+      enc = SQLITE_UTF16NATIVE;
+      break;
+    case SQLITE_ANY: {
+      int rc;
+      rc = sqlite3CreateFunc(db, zFunctionName, nArg,
+           (SQLITE_UTF8|extraFlags)^SQLITE_FUNC_UNSAFE, /* tag-20230109-1 */
+           pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3CreateFunc(db, zFunctionName, nArg,
+             (SQLITE_UTF16LE|extraFlags)^SQLITE_FUNC_UNSAFE, /* tag-20230109-1*/
+             pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
+      }
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      enc = SQLITE_UTF16BE;
+      break;
+    }
+    case SQLITE_UTF8:
+    case SQLITE_UTF16LE:
+    case SQLITE_UTF16BE:
+      break;
+    default:
+      enc = SQLITE_UTF8;
+      break;
+  }
+#else
+  enc = SQLITE_UTF8;
+#endif
+
+  /* Check if an existing function is being overridden or deleted. If so,
+  ** and there are active VMs, then return SQLITE_BUSY. If a function
+  ** is being overridden/deleted but there are no active VMs, allow the
+  ** operation to continue but invalidate all precompiled statements.
+  */
+  p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
+  if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==(u32)enc && p->nArg==nArg ){
+    if( db->nVdbeActive ){
+      sqlite3ErrorWithMsg(db, SQLITE_BUSY,
+        "unable to delete/modify user-function due to active statements");
+      assert( !db->mallocFailed );
+      return SQLITE_BUSY;
+    }else{
+      sqlite3ExpirePreparedStatements(db, 0);
+    }
+  }else if( xSFunc==0 && xFinal==0 ){
+    /* Trying to delete a function that does not exist.  This is a no-op.
+    ** https://sqlite.org/forum/forumpost/726219164b */
+    return SQLITE_OK;
+  }
+
+  p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
+  assert(p || db->mallocFailed);
+  if( !p ){
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  /* If an older version of the function with a configured destructor is
+  ** being replaced invoke the destructor function here. */
+  functionDestroy(db, p);
+
+  if( pDestructor ){
+    pDestructor->nRef++;
+  }
+  p->u.pDestructor = pDestructor;
+  p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
+  testcase( p->funcFlags & SQLITE_DETERMINISTIC );
+  testcase( p->funcFlags & SQLITE_DIRECTONLY );
+  p->xSFunc = xSFunc ? xSFunc : xStep;
+  p->xFinalize = xFinal;
+  p->xValue = xValue;
+  p->xInverse = xInverse;
+  p->pUserData = pUserData;
+  p->nArg = (u16)nArg;
+  return SQLITE_OK;
+}
+
+/*
+** Worker function used by utf-8 APIs that create new functions:
+**
+**    sqlite3_create_function()
+**    sqlite3_create_function_v2()
+**    sqlite3_create_window_function()
+*/
+static int createFunctionApi(
+  sqlite3 *db,
+  const char *zFunc,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
+  void(*xDestroy)(void*)
+){
+  int rc = SQLITE_ERROR;
+  FuncDestructor *pArg = 0;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( xDestroy ){
+    pArg = (FuncDestructor *)sqlite3Malloc(sizeof(FuncDestructor));
+    if( !pArg ){
+      sqlite3OomFault(db);
+      xDestroy(p);
+      goto out;
+    }
+    pArg->nRef = 0;
+    pArg->xDestroy = xDestroy;
+    pArg->pUserData = p;
+  }
+  rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p,
+      xSFunc, xStep, xFinal, xValue, xInverse, pArg
+  );
+  if( pArg && pArg->nRef==0 ){
+    assert( rc!=SQLITE_OK || (xStep==0 && xFinal==0) );
+    xDestroy(p);
+    sqlite3_free(pArg);
+  }
+
+ out:
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Create new user functions.
+*/
+SQLITE_API int sqlite3_create_function(
+  sqlite3 *db,
+  const char *zFunc,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*)
+){
+  return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
+                                    xFinal, 0, 0, 0);
+}
+SQLITE_API int sqlite3_create_function_v2(
+  sqlite3 *db,
+  const char *zFunc,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*),
+  void (*xDestroy)(void *)
+){
+  return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
+                                    xFinal, 0, 0, xDestroy);
+}
+SQLITE_API int sqlite3_create_window_function(
+  sqlite3 *db,
+  const char *zFunc,
+  int nArg,
+  int enc,
+  void *p,
+  void (*xStep)(sqlite3_context*,int,sqlite3_value **),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
+  void (*xDestroy)(void *)
+){
+  return createFunctionApi(db, zFunc, nArg, enc, p, 0, xStep,
+                                    xFinal, xValue, xInverse, xDestroy);
+}
+
+#ifndef SQLITE_OMIT_UTF16
+SQLITE_API int sqlite3_create_function16(
+  sqlite3 *db,
+  const void *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *p,
+  void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+){
+  int rc;
+  char *zFunc8;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
+  rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0,0,0);
+  sqlite3DbFree(db, zFunc8);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+#endif
+
+
+/*
+** The following is the implementation of an SQL function that always
+** fails with an error message stating that the function is used in the
+** wrong context.  The sqlite3_overload_function() API might construct
+** SQL function that use this routine so that the functions will exist
+** for name resolution but are actually overloaded by the xFindFunction
+** method of virtual tables.
+*/
+static void sqlite3InvalidFunction(
+  sqlite3_context *context,  /* The function calling context */
+  int NotUsed,               /* Number of arguments to the function */
+  sqlite3_value **NotUsed2   /* Value of each argument */
+){
+  const char *zName = (const char*)sqlite3_user_data(context);
+  char *zErr;
+  UNUSED_PARAMETER2(NotUsed, NotUsed2);
+  zErr = sqlite3_mprintf(
+      "unable to use function %s in the requested context", zName);
+  sqlite3_result_error(context, zErr, -1);
+  sqlite3_free(zErr);
+}
+
+/*
+** Declare that a function has been overloaded by a virtual table.
+**
+** If the function already exists as a regular global function, then
+** this routine is a no-op.  If the function does not exist, then create
+** a new one that always throws a run-time error.
+**
+** When virtual tables intend to provide an overloaded function, they
+** should call this routine to make sure the global function exists.
+** A global function must exist in order for name resolution to work
+** properly.
+*/
+SQLITE_API int sqlite3_overload_function(
+  sqlite3 *db,
+  const char *zName,
+  int nArg
+){
+  int rc;
+  char *zCopy;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  rc = sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)!=0;
+  sqlite3_mutex_leave(db->mutex);
+  if( rc ) return SQLITE_OK;
+  zCopy = sqlite3_mprintf("%s", zName);
+  if( zCopy==0 ) return SQLITE_NOMEM;
+  return sqlite3_create_function_v2(db, zName, nArg, SQLITE_UTF8,
+                           zCopy, sqlite3InvalidFunction, 0, 0, sqlite3_free);
+}
+
+#ifndef SQLITE_OMIT_TRACE
+/*
+** Register a trace function.  The pArg from the previously registered trace
+** is returned.
+**
+** A NULL trace function means that no tracing is executes.  A non-NULL
+** trace is a pointer to a function that is invoked at the start of each
+** SQL statement.
+*/
+#ifndef SQLITE_OMIT_DEPRECATED
+SQLITE_API void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
+  void *pOld;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pOld = db->pTraceArg;
+  db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
+  db->trace.xLegacy = xTrace;
+  db->pTraceArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pOld;
+}
+#endif /* SQLITE_OMIT_DEPRECATED */
+
+/* Register a trace callback using the version-2 interface.
+*/
+SQLITE_API int sqlite3_trace_v2(
+  sqlite3 *db,                               /* Trace this connection */
+  unsigned mTrace,                           /* Mask of events to be traced */
+  int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
+  void *pArg                                 /* Context */
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( mTrace==0 ) xTrace = 0;
+  if( xTrace==0 ) mTrace = 0;
+  db->mTrace = mTrace;
+  db->trace.xV2 = xTrace;
+  db->pTraceArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** Register a profile function.  The pArg from the previously registered
+** profile function is returned.
+**
+** A NULL profile function means that no profiling is executes.  A non-NULL
+** profile is a pointer to a function that is invoked at the conclusion of
+** each SQL statement that is run.
+*/
+SQLITE_API void *sqlite3_profile(
+  sqlite3 *db,
+  void (*xProfile)(void*,const char*,sqlite_uint64),
+  void *pArg
+){
+  void *pOld;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pOld = db->pProfileArg;
+  db->xProfile = xProfile;
+  db->pProfileArg = pArg;
+  db->mTrace &= SQLITE_TRACE_NONLEGACY_MASK;
+  if( db->xProfile ) db->mTrace |= SQLITE_TRACE_XPROFILE;
+  sqlite3_mutex_leave(db->mutex);
+  return pOld;
+}
+#endif /* SQLITE_OMIT_DEPRECATED */
+#endif /* SQLITE_OMIT_TRACE */
+
+/*
+** Register a function to be invoked when a transaction commits.
+** If the invoked function returns non-zero, then the commit becomes a
+** rollback.
+*/
+SQLITE_API void *sqlite3_commit_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  int (*xCallback)(void*),  /* Function to invoke on each commit */
+  void *pArg                /* Argument to the function */
+){
+  void *pOld;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pOld = db->pCommitArg;
+  db->xCommitCallback = xCallback;
+  db->pCommitArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pOld;
+}
+
+/*
+** Register a callback to be invoked each time a row is updated,
+** inserted or deleted using this database connection.
+*/
+SQLITE_API void *sqlite3_update_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
+  void *pArg                /* Argument to the function */
+){
+  void *pRet;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pUpdateArg;
+  db->xUpdateCallback = xCallback;
+  db->pUpdateArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+}
+
+/*
+** Register a callback to be invoked each time a transaction is rolled
+** back by this database connection.
+*/
+SQLITE_API void *sqlite3_rollback_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  void (*xCallback)(void*), /* Callback function */
+  void *pArg                /* Argument to the function */
+){
+  void *pRet;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pRollbackArg;
+  db->xRollbackCallback = xCallback;
+  db->pRollbackArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+}
+
+#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
+/*
+** Register a callback to be invoked each time a row is updated,
+** inserted or deleted using this database connection.
+*/
+SQLITE_API void *sqlite3_preupdate_hook(
+  sqlite3 *db,              /* Attach the hook to this database */
+  void(*xCallback)(         /* Callback function */
+    void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
+  void *pArg                /* First callback argument */
+){
+  void *pRet;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( db==0 ){
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pPreUpdateArg;
+  db->xPreUpdateCallback = xCallback;
+  db->pPreUpdateArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+}
+#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
+
+/*
+** Register a function to be invoked prior to each autovacuum that
+** determines the number of pages to vacuum.
+*/
+SQLITE_API int sqlite3_autovacuum_pages(
+  sqlite3 *db,                 /* Attach the hook to this database */
+  unsigned int (*xCallback)(void*,const char*,u32,u32,u32),
+  void *pArg,                  /* Argument to the function */
+  void (*xDestructor)(void*)   /* Destructor for pArg */
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    if( xDestructor ) xDestructor(pArg);
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( db->xAutovacDestr ){
+    db->xAutovacDestr(db->pAutovacPagesArg);
+  }
+  db->xAutovacPages = xCallback;
+  db->pAutovacPagesArg = pArg;
+  db->xAutovacDestr = xDestructor;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
+** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
+** is greater than sqlite3.pWalArg cast to an integer (the value configured by
+** wal_autocheckpoint()).
+*/
+SQLITE_PRIVATE int sqlite3WalDefaultHook(
+  void *pClientData,     /* Argument */
+  sqlite3 *db,           /* Connection */
+  const char *zDb,       /* Database */
+  int nFrame             /* Size of WAL */
+){
+  if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
+    sqlite3BeginBenignMalloc();
+    sqlite3_wal_checkpoint(db, zDb);
+    sqlite3EndBenignMalloc();
+  }
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_WAL */
+
+/*
+** Configure an sqlite3_wal_hook() callback to automatically checkpoint
+** a database after committing a transaction if there are nFrame or
+** more frames in the log file. Passing zero or a negative value as the
+** nFrame parameter disables automatic checkpoints entirely.
+**
+** The callback registered by this function replaces any existing callback
+** registered using sqlite3_wal_hook(). Likewise, registering a callback
+** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
+** configured by this function.
+*/
+SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
+#ifdef SQLITE_OMIT_WAL
+  UNUSED_PARAMETER(db);
+  UNUSED_PARAMETER(nFrame);
+#else
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  if( nFrame>0 ){
+    sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
+  }else{
+    sqlite3_wal_hook(db, 0, 0);
+  }
+#endif
+  return SQLITE_OK;
+}
+
+/*
+** Register a callback to be invoked each time a transaction is written
+** into the write-ahead-log by this database connection.
+*/
+SQLITE_API void *sqlite3_wal_hook(
+  sqlite3 *db,                    /* Attach the hook to this db handle */
+  int(*xCallback)(void *, sqlite3*, const char*, int),
+  void *pArg                      /* First argument passed to xCallback() */
+){
+#ifndef SQLITE_OMIT_WAL
+  void *pRet;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pRet = db->pWalArg;
+  db->xWalCallback = xCallback;
+  db->pWalArg = pArg;
+  sqlite3_mutex_leave(db->mutex);
+  return pRet;
+#else
+  return 0;
+#endif
+}
+
+/*
+** Checkpoint database zDb.
+*/
+SQLITE_API int sqlite3_wal_checkpoint_v2(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of attached database (or NULL) */
+  int eMode,                      /* SQLITE_CHECKPOINT_* value */
+  int *pnLog,                     /* OUT: Size of WAL log in frames */
+  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
+){
+#ifdef SQLITE_OMIT_WAL
+  return SQLITE_OK;
+#else
+  int rc;                         /* Return code */
+  int iDb;                        /* Schema to checkpoint */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+
+  /* Initialize the output variables to -1 in case an error occurs. */
+  if( pnLog ) *pnLog = -1;
+  if( pnCkpt ) *pnCkpt = -1;
+
+  assert( SQLITE_CHECKPOINT_PASSIVE==0 );
+  assert( SQLITE_CHECKPOINT_FULL==1 );
+  assert( SQLITE_CHECKPOINT_RESTART==2 );
+  assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
+  if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
+    /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
+    ** mode: */
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  sqlite3_mutex_enter(db->mutex);
+  if( zDb && zDb[0] ){
+    iDb = sqlite3FindDbName(db, zDb);
+  }else{
+    iDb = SQLITE_MAX_DB;   /* This means process all schemas */
+  }
+  if( iDb<0 ){
+    rc = SQLITE_ERROR;
+    sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
+  }else{
+    db->busyHandler.nBusy = 0;
+    rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
+    sqlite3Error(db, rc);
+  }
+  rc = sqlite3ApiExit(db, rc);
+
+  /* If there are no active statements, clear the interrupt flag at this
+  ** point.  */
+  if( db->nVdbeActive==0 ){
+    AtomicStore(&db->u1.isInterrupted, 0);
+  }
+
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+#endif
+}
+
+
+/*
+** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
+** to contains a zero-length string, all attached databases are
+** checkpointed.
+*/
+SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
+  /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
+  ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
+  return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
+}
+
+#ifndef SQLITE_OMIT_WAL
+/*
+** Run a checkpoint on database iDb. This is a no-op if database iDb is
+** not currently open in WAL mode.
+**
+** If a transaction is open on the database being checkpointed, this
+** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
+** an error occurs while running the checkpoint, an SQLite error code is
+** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
+**
+** The mutex on database handle db should be held by the caller. The mutex
+** associated with the specific b-tree being checkpointed is taken by
+** this function while the checkpoint is running.
+**
+** If iDb is passed SQLITE_MAX_DB then all attached databases are
+** checkpointed. If an error is encountered it is returned immediately -
+** no attempt is made to checkpoint any remaining databases.
+**
+** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL, RESTART
+** or TRUNCATE.
+*/
+SQLITE_PRIVATE int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Used to iterate through attached dbs */
+  int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  assert( !pnLog || *pnLog==-1 );
+  assert( !pnCkpt || *pnCkpt==-1 );
+  testcase( iDb==SQLITE_MAX_ATTACHED ); /* See forum post a006d86f72 */
+  testcase( iDb==SQLITE_MAX_DB );
+
+  for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
+    if( i==iDb || iDb==SQLITE_MAX_DB ){
+      rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
+      pnLog = 0;
+      pnCkpt = 0;
+      if( rc==SQLITE_BUSY ){
+        bBusy = 1;
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+  return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
+}
+#endif /* SQLITE_OMIT_WAL */
+
+/*
+** This function returns true if main-memory should be used instead of
+** a temporary file for transient pager files and statement journals.
+** The value returned depends on the value of db->temp_store (runtime
+** parameter) and the compile time value of SQLITE_TEMP_STORE. The
+** following table describes the relationship between these two values
+** and this functions return value.
+**
+**   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
+**   -----------------     --------------     ------------------------------
+**   0                     any                file      (return 0)
+**   1                     1                  file      (return 0)
+**   1                     2                  memory    (return 1)
+**   1                     0                  file      (return 0)
+**   2                     1                  file      (return 0)
+**   2                     2                  memory    (return 1)
+**   2                     0                  memory    (return 1)
+**   3                     any                memory    (return 1)
+*/
+SQLITE_PRIVATE int sqlite3TempInMemory(const sqlite3 *db){
+#if SQLITE_TEMP_STORE==1
+  return ( db->temp_store==2 );
+#endif
+#if SQLITE_TEMP_STORE==2
+  return ( db->temp_store!=1 );
+#endif
+#if SQLITE_TEMP_STORE==3
+  UNUSED_PARAMETER(db);
+  return 1;
+#endif
+#if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
+  UNUSED_PARAMETER(db);
+  return 0;
+#endif
+}
+
+/*
+** Return UTF-8 encoded English language explanation of the most recent
+** error.
+*/
+SQLITE_API const char *sqlite3_errmsg(sqlite3 *db){
+  const char *z;
+  if( !db ){
+    return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
+  }
+  if( !sqlite3SafetyCheckSickOrOk(db) ){
+    return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
+  }
+  sqlite3_mutex_enter(db->mutex);
+  if( db->mallocFailed ){
+    z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
+  }else{
+    testcase( db->pErr==0 );
+    z = db->errCode ? (char*)sqlite3_value_text(db->pErr) : 0;
+    assert( !db->mallocFailed );
+    if( z==0 ){
+      z = sqlite3ErrStr(db->errCode);
+    }
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return z;
+}
+
+/*
+** Return the byte offset of the most recent error
+*/
+SQLITE_API int sqlite3_error_offset(sqlite3 *db){
+  int iOffset = -1;
+  if( db && sqlite3SafetyCheckSickOrOk(db) && db->errCode ){
+    sqlite3_mutex_enter(db->mutex);
+    iOffset = db->errByteOffset;
+    sqlite3_mutex_leave(db->mutex);
+  }
+  return iOffset;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Return UTF-16 encoded English language explanation of the most recent
+** error.
+*/
+SQLITE_API const void *sqlite3_errmsg16(sqlite3 *db){
+  static const u16 outOfMem[] = {
+    'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
+  };
+  static const u16 misuse[] = {
+    'b', 'a', 'd', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'e', 'r', ' ',
+    'o', 'r', ' ', 'o', 't', 'h', 'e', 'r', ' ', 'A', 'P', 'I', ' ',
+    'm', 'i', 's', 'u', 's', 'e', 0
+  };
+
+  const void *z;
+  if( !db ){
+    return (void *)outOfMem;
+  }
+  if( !sqlite3SafetyCheckSickOrOk(db) ){
+    return (void *)misuse;
+  }
+  sqlite3_mutex_enter(db->mutex);
+  if( db->mallocFailed ){
+    z = (void *)outOfMem;
+  }else{
+    z = sqlite3_value_text16(db->pErr);
+    if( z==0 ){
+      sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
+      z = sqlite3_value_text16(db->pErr);
+    }
+    /* A malloc() may have failed within the call to sqlite3_value_text16()
+    ** above. If this is the case, then the db->mallocFailed flag needs to
+    ** be cleared before returning. Do this directly, instead of via
+    ** sqlite3ApiExit(), to avoid setting the database handle error message.
+    */
+    sqlite3OomClear(db);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return z;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Return the most recent error code generated by an SQLite routine. If NULL is
+** passed to this function, we assume a malloc() failed during sqlite3_open().
+*/
+SQLITE_API int sqlite3_errcode(sqlite3 *db){
+  if( db && !sqlite3SafetyCheckSickOrOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  if( !db || db->mallocFailed ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  return db->errCode & db->errMask;
+}
+SQLITE_API int sqlite3_extended_errcode(sqlite3 *db){
+  if( db && !sqlite3SafetyCheckSickOrOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+  if( !db || db->mallocFailed ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  return db->errCode;
+}
+SQLITE_API int sqlite3_system_errno(sqlite3 *db){
+  return db ? db->iSysErrno : 0;
+}
+
+/*
+** Return a string that describes the kind of error specified in the
+** argument.  For now, this simply calls the internal sqlite3ErrStr()
+** function.
+*/
+SQLITE_API const char *sqlite3_errstr(int rc){
+  return sqlite3ErrStr(rc);
+}
+
+/*
+** Create a new collating function for database "db".  The name is zName
+** and the encoding is enc.
+*/
+static int createCollation(
+  sqlite3* db,
+  const char *zName,
+  u8 enc,
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDel)(void*)
+){
+  CollSeq *pColl;
+  int enc2;
+
+  assert( sqlite3_mutex_held(db->mutex) );
+
+  /* If SQLITE_UTF16 is specified as the encoding type, transform this
+  ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
+  ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
+  */
+  enc2 = enc;
+  testcase( enc2==SQLITE_UTF16 );
+  testcase( enc2==SQLITE_UTF16_ALIGNED );
+  if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
+    enc2 = SQLITE_UTF16NATIVE;
+  }
+  if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
+    return SQLITE_MISUSE_BKPT;
+  }
+
+  /* Check if this call is removing or replacing an existing collation
+  ** sequence. If so, and there are active VMs, return busy. If there
+  ** are no active VMs, invalidate any pre-compiled statements.
+  */
+  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
+  if( pColl && pColl->xCmp ){
+    if( db->nVdbeActive ){
+      sqlite3ErrorWithMsg(db, SQLITE_BUSY,
+        "unable to delete/modify collation sequence due to active statements");
+      return SQLITE_BUSY;
+    }
+    sqlite3ExpirePreparedStatements(db, 0);
+
+    /* If collation sequence pColl was created directly by a call to
+    ** sqlite3_create_collation, and not generated by synthCollSeq(),
+    ** then any copies made by synthCollSeq() need to be invalidated.
+    ** Also, collation destructor - CollSeq.xDel() - function may need
+    ** to be called.
+    */
+    if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
+      CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
+      int j;
+      for(j=0; j<3; j++){
+        CollSeq *p = &aColl[j];
+        if( p->enc==pColl->enc ){
+          if( p->xDel ){
+            p->xDel(p->pUser);
+          }
+          p->xCmp = 0;
+        }
+      }
+    }
+  }
+
+  pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
+  if( pColl==0 ) return SQLITE_NOMEM_BKPT;
+  pColl->xCmp = xCompare;
+  pColl->pUser = pCtx;
+  pColl->xDel = xDel;
+  pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
+  sqlite3Error(db, SQLITE_OK);
+  return SQLITE_OK;
+}
+
+
+/*
+** This array defines hard upper bounds on limit values.  The
+** initializer must be kept in sync with the SQLITE_LIMIT_*
+** #defines in sqlite3.h.
+*/
+static const int aHardLimit[] = {
+  SQLITE_MAX_LENGTH,
+  SQLITE_MAX_SQL_LENGTH,
+  SQLITE_MAX_COLUMN,
+  SQLITE_MAX_EXPR_DEPTH,
+  SQLITE_MAX_COMPOUND_SELECT,
+  SQLITE_MAX_VDBE_OP,
+  SQLITE_MAX_FUNCTION_ARG,
+  SQLITE_MAX_ATTACHED,
+  SQLITE_MAX_LIKE_PATTERN_LENGTH,
+  SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
+  SQLITE_MAX_TRIGGER_DEPTH,
+  SQLITE_MAX_WORKER_THREADS,
+};
+
+/*
+** Make sure the hard limits are set to reasonable values
+*/
+#if SQLITE_MAX_LENGTH<100
+# error SQLITE_MAX_LENGTH must be at least 100
+#endif
+#if SQLITE_MAX_SQL_LENGTH<100
+# error SQLITE_MAX_SQL_LENGTH must be at least 100
+#endif
+#if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
+# error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
+#endif
+#if SQLITE_MAX_COMPOUND_SELECT<2
+# error SQLITE_MAX_COMPOUND_SELECT must be at least 2
+#endif
+#if SQLITE_MAX_VDBE_OP<40
+# error SQLITE_MAX_VDBE_OP must be at least 40
+#endif
+#if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>32767
+# error SQLITE_MAX_FUNCTION_ARG must be between 0 and 32767
+#endif
+#if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
+# error SQLITE_MAX_ATTACHED must be between 0 and 125
+#endif
+#if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
+# error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
+#endif
+#if SQLITE_MAX_COLUMN>32767
+# error SQLITE_MAX_COLUMN must not exceed 32767
+#endif
+#if SQLITE_MAX_TRIGGER_DEPTH<1
+# error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
+#endif
+#if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
+# error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
+#endif
+
+
+/*
+** Change the value of a limit.  Report the old value.
+** If an invalid limit index is supplied, report -1.
+** Make no changes but still report the old value if the
+** new limit is negative.
+**
+** A new lower limit does not shrink existing constructs.
+** It merely prevents new constructs that exceed the limit
+** from forming.
+*/
+SQLITE_API int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
+  int oldLimit;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return -1;
+  }
+#endif
+
+  /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
+  ** there is a hard upper bound set at compile-time by a C preprocessor
+  ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
+  ** "_MAX_".)
+  */
+  assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
+  assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
+  assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
+  assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
+  assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
+  assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
+  assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
+  assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
+  assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
+                                               SQLITE_MAX_LIKE_PATTERN_LENGTH );
+  assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
+  assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
+  assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
+  assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
+
+
+  if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
+    return -1;
+  }
+  oldLimit = db->aLimit[limitId];
+  if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
+    if( newLimit>aHardLimit[limitId] ){
+      newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
+    }else if( newLimit<SQLITE_MIN_LENGTH && limitId==SQLITE_LIMIT_LENGTH ){
+      newLimit = SQLITE_MIN_LENGTH;
+    }
+    db->aLimit[limitId] = newLimit;
+  }
+  return oldLimit;                     /* IMP: R-53341-35419 */
+}
+
+/*
+** This function is used to parse both URIs and non-URI filenames passed by the
+** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
+** URIs specified as part of ATTACH statements.
+**
+** The first argument to this function is the name of the VFS to use (or
+** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
+** query parameter. The second argument contains the URI (or non-URI filename)
+** itself. When this function is called the *pFlags variable should contain
+** the default flags to open the database handle with. The value stored in
+** *pFlags may be updated before returning if the URI filename contains
+** "cache=xxx" or "mode=xxx" query parameters.
+**
+** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
+** the VFS that should be used to open the database file. *pzFile is set to
+** point to a buffer containing the name of the file to open.  The value
+** stored in *pzFile is a database name acceptable to sqlite3_uri_parameter()
+** and is in the same format as names created using sqlite3_create_filename().
+** The caller must invoke sqlite3_free_filename() (not sqlite3_free()!) on
+** the value returned in *pzFile to avoid a memory leak.
+**
+** If an error occurs, then an SQLite error code is returned and *pzErrMsg
+** may be set to point to a buffer containing an English language error
+** message. It is the responsibility of the caller to eventually release
+** this buffer by calling sqlite3_free().
+*/
+SQLITE_PRIVATE int sqlite3ParseUri(
+  const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
+  const char *zUri,               /* Nul-terminated URI to parse */
+  unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
+  sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
+  char **pzFile,                  /* OUT: Filename component of URI */
+  char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
+){
+  int rc = SQLITE_OK;
+  unsigned int flags = *pFlags;
+  const char *zVfs = zDefaultVfs;
+  char *zFile;
+  char c;
+  int nUri = sqlite3Strlen30(zUri);
+
+  assert( *pzErrMsg==0 );
+
+  if( ((flags & SQLITE_OPEN_URI)                     /* IMP: R-48725-32206 */
+       || AtomicLoad(&sqlite3GlobalConfig.bOpenUri)) /* IMP: R-51689-46548 */
+   && nUri>=5 && memcmp(zUri, "file:", 5)==0         /* IMP: R-57884-37496 */
+  ){
+    char *zOpt;
+    int eState;                   /* Parser state when parsing URI */
+    int iIn;                      /* Input character index */
+    int iOut = 0;                 /* Output character index */
+    u64 nByte = nUri+8;           /* Bytes of space to allocate */
+
+    /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
+    ** method that there may be extra parameters following the file-name.  */
+    flags |= SQLITE_OPEN_URI;
+
+    for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
+    zFile = sqlite3_malloc64(nByte);
+    if( !zFile ) return SQLITE_NOMEM_BKPT;
+
+    memset(zFile, 0, 4);  /* 4-byte of 0x00 is the start of DB name marker */
+    zFile += 4;
+
+    iIn = 5;
+#ifdef SQLITE_ALLOW_URI_AUTHORITY
+    if( strncmp(zUri+5, "///", 3)==0 ){
+      iIn = 7;
+      /* The following condition causes URIs with five leading / characters
+      ** like file://///host/path to be converted into UNCs like //host/path.
+      ** The correct URI for that UNC has only two or four leading / characters
+      ** file://host/path or file:////host/path.  But 5 leading slashes is a
+      ** common error, we are told, so we handle it as a special case. */
+      if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
+    }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
+      iIn = 16;
+    }
+#else
+    /* Discard the scheme and authority segments of the URI. */
+    if( zUri[5]=='/' && zUri[6]=='/' ){
+      iIn = 7;
+      while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
+      if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
+        *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
+            iIn-7, &zUri[7]);
+        rc = SQLITE_ERROR;
+        goto parse_uri_out;
+      }
+    }
+#endif
+
+    /* Copy the filename and any query parameters into the zFile buffer.
+    ** Decode %HH escape codes along the way.
+    **
+    ** Within this loop, variable eState may be set to 0, 1 or 2, depending
+    ** on the parsing context. As follows:
+    **
+    **   0: Parsing file-name.
+    **   1: Parsing name section of a name=value query parameter.
+    **   2: Parsing value section of a name=value query parameter.
+    */
+    eState = 0;
+    while( (c = zUri[iIn])!=0 && c!='#' ){
+      iIn++;
+      if( c=='%'
+       && sqlite3Isxdigit(zUri[iIn])
+       && sqlite3Isxdigit(zUri[iIn+1])
+      ){
+        int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
+        octet += sqlite3HexToInt(zUri[iIn++]);
+
+        assert( octet>=0 && octet<256 );
+        if( octet==0 ){
+#ifndef SQLITE_ENABLE_URI_00_ERROR
+          /* This branch is taken when "%00" appears within the URI. In this
+          ** case we ignore all text in the remainder of the path, name or
+          ** value currently being parsed. So ignore the current character
+          ** and skip to the next "?", "=" or "&", as appropriate. */
+          while( (c = zUri[iIn])!=0 && c!='#'
+              && (eState!=0 || c!='?')
+              && (eState!=1 || (c!='=' && c!='&'))
+              && (eState!=2 || c!='&')
+          ){
+            iIn++;
+          }
+          continue;
+#else
+          /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
+          *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
+          rc = SQLITE_ERROR;
+          goto parse_uri_out;
+#endif
+        }
+        c = octet;
+      }else if( eState==1 && (c=='&' || c=='=') ){
+        if( zFile[iOut-1]==0 ){
+          /* An empty option name. Ignore this option altogether. */
+          while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
+          continue;
+        }
+        if( c=='&' ){
+          zFile[iOut++] = '\0';
+        }else{
+          eState = 2;
+        }
+        c = 0;
+      }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
+        c = 0;
+        eState = 1;
+      }
+      zFile[iOut++] = c;
+    }
+    if( eState==1 ) zFile[iOut++] = '\0';
+    memset(zFile+iOut, 0, 4); /* end-of-options + empty journal filenames */
+
+    /* Check if there were any options specified that should be interpreted
+    ** here. Options that are interpreted here include "vfs" and those that
+    ** correspond to flags that may be passed to the sqlite3_open_v2()
+    ** method. */
+    zOpt = &zFile[sqlite3Strlen30(zFile)+1];
+    while( zOpt[0] ){
+      int nOpt = sqlite3Strlen30(zOpt);
+      char *zVal = &zOpt[nOpt+1];
+      int nVal = sqlite3Strlen30(zVal);
+
+      if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
+        zVfs = zVal;
+      }else{
+        struct OpenMode {
+          const char *z;
+          int mode;
+        } *aMode = 0;
+        char *zModeType = 0;
+        int mask = 0;
+        int limit = 0;
+
+        if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
+          static struct OpenMode aCacheMode[] = {
+            { "shared",  SQLITE_OPEN_SHAREDCACHE },
+            { "private", SQLITE_OPEN_PRIVATECACHE },
+            { 0, 0 }
+          };
+
+          mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
+          aMode = aCacheMode;
+          limit = mask;
+          zModeType = "cache";
+        }
+        if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
+          static struct OpenMode aOpenMode[] = {
+            { "ro",  SQLITE_OPEN_READONLY },
+            { "rw",  SQLITE_OPEN_READWRITE },
+            { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
+            { "memory", SQLITE_OPEN_MEMORY },
+            { 0, 0 }
+          };
+
+          mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
+                   | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
+          aMode = aOpenMode;
+          limit = mask & flags;
+          zModeType = "access";
+        }
+
+        if( aMode ){
+          int i;
+          int mode = 0;
+          for(i=0; aMode[i].z; i++){
+            const char *z = aMode[i].z;
+            if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
+              mode = aMode[i].mode;
+              break;
+            }
+          }
+          if( mode==0 ){
+            *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
+            rc = SQLITE_ERROR;
+            goto parse_uri_out;
+          }
+          if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
+            *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
+                                        zModeType, zVal);
+            rc = SQLITE_PERM;
+            goto parse_uri_out;
+          }
+          flags = (flags & ~mask) | mode;
+        }
+      }
+
+      zOpt = &zVal[nVal+1];
+    }
+
+  }else{
+    zFile = sqlite3_malloc64(nUri+8);
+    if( !zFile ) return SQLITE_NOMEM_BKPT;
+    memset(zFile, 0, 4);
+    zFile += 4;
+    if( nUri ){
+      memcpy(zFile, zUri, nUri);
+    }
+    memset(zFile+nUri, 0, 4);
+    flags &= ~SQLITE_OPEN_URI;
+  }
+
+  *ppVfs = sqlite3_vfs_find(zVfs);
+  if( *ppVfs==0 ){
+    *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
+    rc = SQLITE_ERROR;
+  }
+ parse_uri_out:
+  if( rc!=SQLITE_OK ){
+    sqlite3_free_filename(zFile);
+    zFile = 0;
+  }
+  *pFlags = flags;
+  *pzFile = zFile;
+  return rc;
+}
+
+/*
+** This routine does the core work of extracting URI parameters from a
+** database filename for the sqlite3_uri_parameter() interface.
+*/
+static const char *uriParameter(const char *zFilename, const char *zParam){
+  zFilename += sqlite3Strlen30(zFilename) + 1;
+  while( ALWAYS(zFilename!=0) && zFilename[0] ){
+    int x = strcmp(zFilename, zParam);
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+    if( x==0 ) return zFilename;
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+  }
+  return 0;
+}
+
+
+
+/*
+** This routine does the work of opening a database on behalf of
+** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
+** is UTF-8 encoded.
+*/
+static int openDatabase(
+  const char *zFilename, /* Database filename UTF-8 encoded */
+  sqlite3 **ppDb,        /* OUT: Returned database handle */
+  unsigned int flags,    /* Operational flags */
+  const char *zVfs       /* Name of the VFS to use */
+){
+  sqlite3 *db;                    /* Store allocated handle here */
+  int rc;                         /* Return code */
+  int isThreadsafe;               /* True for threadsafe connections */
+  char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
+  char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
+  int i;                          /* Loop counter */
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *ppDb = 0;
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+
+  if( sqlite3GlobalConfig.bCoreMutex==0 ){
+    isThreadsafe = 0;
+  }else if( flags & SQLITE_OPEN_NOMUTEX ){
+    isThreadsafe = 0;
+  }else if( flags & SQLITE_OPEN_FULLMUTEX ){
+    isThreadsafe = 1;
+  }else{
+    isThreadsafe = sqlite3GlobalConfig.bFullMutex;
+  }
+
+  if( flags & SQLITE_OPEN_PRIVATECACHE ){
+    flags &= ~SQLITE_OPEN_SHAREDCACHE;
+  }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
+    flags |= SQLITE_OPEN_SHAREDCACHE;
+  }
+
+  /* Remove harmful bits from the flags parameter
+  **
+  ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
+  ** dealt with in the previous code block.  Besides these, the only
+  ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
+  ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
+  ** SQLITE_OPEN_PRIVATECACHE, SQLITE_OPEN_EXRESCODE, and some reserved
+  ** bits.  Silently mask off all other flags.
+  */
+  flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
+               SQLITE_OPEN_EXCLUSIVE |
+               SQLITE_OPEN_MAIN_DB |
+               SQLITE_OPEN_TEMP_DB |
+               SQLITE_OPEN_TRANSIENT_DB |
+               SQLITE_OPEN_MAIN_JOURNAL |
+               SQLITE_OPEN_TEMP_JOURNAL |
+               SQLITE_OPEN_SUBJOURNAL |
+               SQLITE_OPEN_SUPER_JOURNAL |
+               SQLITE_OPEN_NOMUTEX |
+               SQLITE_OPEN_FULLMUTEX |
+               SQLITE_OPEN_WAL
+             );
+
+  /* Allocate the sqlite data structure */
+  db = sqlite3MallocZero( sizeof(sqlite3) );
+  if( db==0 ) goto opendb_out;
+  if( isThreadsafe
+#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
+   || sqlite3GlobalConfig.bCoreMutex
+#endif
+  ){
+    db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
+    if( db->mutex==0 ){
+      sqlite3_free(db);
+      db = 0;
+      goto opendb_out;
+    }
+    if( isThreadsafe==0 ){
+      sqlite3MutexWarnOnContention(db->mutex);
+    }
+  }
+  sqlite3_mutex_enter(db->mutex);
+  db->errMask = (flags & SQLITE_OPEN_EXRESCODE)!=0 ? 0xffffffff : 0xff;
+  db->nDb = 2;
+  db->eOpenState = SQLITE_STATE_BUSY;
+  db->aDb = db->aDbStatic;
+  db->lookaside.bDisable = 1;
+  db->lookaside.sz = 0;
+
+  assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
+  memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
+  db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
+  db->autoCommit = 1;
+  db->nextAutovac = -1;
+  db->szMmap = sqlite3GlobalConfig.szMmap;
+  db->nextPagesize = 0;
+  db->init.azInit = sqlite3StdType; /* Any array of string ptrs will do */
+#ifdef SQLITE_ENABLE_SORTER_MMAP
+  /* Beginning with version 3.37.0, using the VFS xFetch() API to memory-map
+  ** the temporary files used to do external sorts (see code in vdbesort.c)
+  ** is disabled. It can still be used either by defining
+  ** SQLITE_ENABLE_SORTER_MMAP at compile time or by using the
+  ** SQLITE_TESTCTRL_SORTER_MMAP test-control at runtime. */
+  db->nMaxSorterMmap = 0x7FFFFFFF;
+#endif
+  db->flags |= SQLITE_ShortColNames
+                 | SQLITE_EnableTrigger
+                 | SQLITE_EnableView
+                 | SQLITE_CacheSpill
+                 | SQLITE_AttachCreate
+                 | SQLITE_AttachWrite
+                 | SQLITE_Comments
+#if !defined(SQLITE_TRUSTED_SCHEMA) || SQLITE_TRUSTED_SCHEMA+0!=0
+                 | SQLITE_TrustedSchema
+#endif
+/* The SQLITE_DQS compile-time option determines the default settings
+** for SQLITE_DBCONFIG_DQS_DDL and SQLITE_DBCONFIG_DQS_DML.
+**
+**    SQLITE_DQS     SQLITE_DBCONFIG_DQS_DDL    SQLITE_DBCONFIG_DQS_DML
+**    ----------     -----------------------    -----------------------
+**     undefined               on                          on
+**         3                   on                          on
+**         2                   on                         off
+**         1                  off                          on
+**         0                  off                         off
+**
+** Legacy behavior is 3 (double-quoted string literals are allowed anywhere)
+** and so that is the default.  But developers are encouraged to use
+** -DSQLITE_DQS=0 (best) or -DSQLITE_DQS=1 (second choice) if possible.
+*/
+#if !defined(SQLITE_DQS)
+# define SQLITE_DQS 3
+#endif
+#if (SQLITE_DQS&1)==1
+                 | SQLITE_DqsDML
+#endif
+#if (SQLITE_DQS&2)==2
+                 | SQLITE_DqsDDL
+#endif
+
+#if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
+                 | SQLITE_AutoIndex
+#endif
+#if SQLITE_DEFAULT_CKPTFULLFSYNC
+                 | SQLITE_CkptFullFSync
+#endif
+#if SQLITE_DEFAULT_FILE_FORMAT<4
+                 | SQLITE_LegacyFileFmt
+#endif
+#ifdef SQLITE_ENABLE_LOAD_EXTENSION
+                 | SQLITE_LoadExtension
+#endif
+#if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
+                 | SQLITE_RecTriggers
+#endif
+#if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
+                 | SQLITE_ForeignKeys
+#endif
+#if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
+                 | SQLITE_ReverseOrder
+#endif
+#if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
+                 | SQLITE_CellSizeCk
+#endif
+#if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
+                 | SQLITE_Fts3Tokenizer
+#endif
+#if defined(SQLITE_ENABLE_QPSG)
+                 | SQLITE_EnableQPSG
+#endif
+#if defined(SQLITE_DEFAULT_DEFENSIVE)
+                 | SQLITE_Defensive
+#endif
+#if defined(SQLITE_DEFAULT_LEGACY_ALTER_TABLE)
+                 | SQLITE_LegacyAlter
+#endif
+#if defined(SQLITE_ENABLE_STMT_SCANSTATUS)
+                 | SQLITE_StmtScanStatus
+#endif
+      ;
+  sqlite3HashInit(&db->aCollSeq);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  sqlite3HashInit(&db->aModule);
+#endif
+
+  /* Add the default collation sequence BINARY. BINARY works for both UTF-8
+  ** and UTF-16, so add a version for each to avoid any unnecessary
+  ** conversions. The only error that can occur here is a malloc() failure.
+  **
+  ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
+  ** functions:
+  */
+  createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
+  createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
+  createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
+  createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
+  createCollation(db, "RTRIM", SQLITE_UTF8, 0, rtrimCollFunc, 0);
+  if( db->mallocFailed ){
+    goto opendb_out;
+  }
+
+#if SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL)
+  /* Process magic filenames ":localStorage:" and ":sessionStorage:" */
+  if( zFilename && zFilename[0]==':' ){
+    if( strcmp(zFilename, ":localStorage:")==0 ){
+      zFilename = "file:local?vfs=kvvfs";
+      flags |= SQLITE_OPEN_URI;
+    }else if( strcmp(zFilename, ":sessionStorage:")==0 ){
+      zFilename = "file:session?vfs=kvvfs";
+      flags |= SQLITE_OPEN_URI;
+    }
+  }
+#endif /* SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL) */
+
+  /* Parse the filename/URI argument
+  **
+  ** Only allow sensible combinations of bits in the flags argument.
+  ** Throw an error if any non-sense combination is used.  If we
+  ** do not block illegal combinations here, it could trigger
+  ** assert() statements in deeper layers.  Sensible combinations
+  ** are:
+  **
+  **  1:  SQLITE_OPEN_READONLY
+  **  2:  SQLITE_OPEN_READWRITE
+  **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
+  */
+  db->openFlags = flags;
+  assert( SQLITE_OPEN_READONLY  == 0x01 );
+  assert( SQLITE_OPEN_READWRITE == 0x02 );
+  assert( SQLITE_OPEN_CREATE    == 0x04 );
+  testcase( (1<<(flags&7))==0x02 ); /* READONLY */
+  testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
+  testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
+  if( ((1<<(flags&7)) & 0x46)==0 ){
+    rc = SQLITE_MISUSE_BKPT;  /* IMP: R-18321-05872 */
+  }else{
+    if( zFilename==0 ) zFilename = ":memory:";
+    rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
+  }
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
+    sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
+    sqlite3_free(zErrMsg);
+    goto opendb_out;
+  }
+  assert( db->pVfs!=0 );
+#if SQLITE_OS_KV || defined(SQLITE_OS_KV_OPTIONAL)
+  if( sqlite3_stricmp(db->pVfs->zName, "kvvfs")==0 ){
+    db->temp_store = 2;
+  }
+#endif
+
+  /* Open the backend database driver */
+  rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
+                        flags | SQLITE_OPEN_MAIN_DB);
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_IOERR_NOMEM ){
+      rc = SQLITE_NOMEM_BKPT;
+    }
+    sqlite3Error(db, rc);
+    goto opendb_out;
+  }
+  sqlite3BtreeEnter(db->aDb[0].pBt);
+  db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
+  if( !db->mallocFailed ){
+    sqlite3SetTextEncoding(db, SCHEMA_ENC(db));
+  }
+  sqlite3BtreeLeave(db->aDb[0].pBt);
+  db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
+
+  /* The default safety_level for the main database is FULL; for the temp
+  ** database it is OFF. This matches the pager layer defaults.
+  */
+  db->aDb[0].zDbSName = "main";
+  db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
+  db->aDb[1].zDbSName = "temp";
+  db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
+
+  db->eOpenState = SQLITE_STATE_OPEN;
+  if( db->mallocFailed ){
+    goto opendb_out;
+  }
+
+  /* Register all built-in functions, but do not attempt to read the
+  ** database schema yet. This is delayed until the first time the database
+  ** is accessed.
+  */
+  sqlite3Error(db, SQLITE_OK);
+  sqlite3RegisterPerConnectionBuiltinFunctions(db);
+  rc = sqlite3_errcode(db);
+
+
+  /* Load compiled-in extensions */
+  for(i=0; rc==SQLITE_OK && i<ArraySize(sqlite3BuiltinExtensions); i++){
+    rc = sqlite3BuiltinExtensions[i](db);
+  }
+
+  /* Load automatic extensions - extensions that have been registered
+  ** using the sqlite3_automatic_extension() API.
+  */
+  if( rc==SQLITE_OK ){
+    sqlite3AutoLoadExtensions(db);
+    rc = sqlite3_errcode(db);
+    if( rc!=SQLITE_OK ){
+      goto opendb_out;
+    }
+  }
+
+#ifdef SQLITE_ENABLE_INTERNAL_FUNCTIONS
+  /* Testing use only!!! The -DSQLITE_ENABLE_INTERNAL_FUNCTIONS=1 compile-time
+  ** option gives access to internal functions by default.
+  ** Testing use only!!! */
+  db->mDbFlags |= DBFLAG_InternalFunc;
+#endif
+
+  /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
+  ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
+  ** mode.  Doing nothing at all also makes NORMAL the default.
+  */
+#ifdef SQLITE_DEFAULT_LOCKING_MODE
+  db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
+  sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
+                          SQLITE_DEFAULT_LOCKING_MODE);
+#endif
+
+  if( rc ) sqlite3Error(db, rc);
+
+  /* Enable the lookaside-malloc subsystem */
+  setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
+                        sqlite3GlobalConfig.nLookaside);
+
+  sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
+
+opendb_out:
+  if( db ){
+    assert( db->mutex!=0 || isThreadsafe==0
+           || sqlite3GlobalConfig.bFullMutex==0 );
+    sqlite3_mutex_leave(db->mutex);
+  }
+  rc = sqlite3_errcode(db);
+  assert( db!=0 || (rc&0xff)==SQLITE_NOMEM );
+  if( (rc&0xff)==SQLITE_NOMEM ){
+    sqlite3_close(db);
+    db = 0;
+  }else if( rc!=SQLITE_OK ){
+    db->eOpenState = SQLITE_STATE_SICK;
+  }
+  *ppDb = db;
+#ifdef SQLITE_ENABLE_SQLLOG
+  if( sqlite3GlobalConfig.xSqllog ){
+    /* Opening a db handle. Fourth parameter is passed 0. */
+    void *pArg = sqlite3GlobalConfig.pSqllogArg;
+    sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
+  }
+#endif
+  sqlite3_free_filename(zOpen);
+  return rc;
+}
+
+
+/*
+** Open a new database handle.
+*/
+SQLITE_API int sqlite3_open(
+  const char *zFilename,
+  sqlite3 **ppDb
+){
+  return openDatabase(zFilename, ppDb,
+                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
+}
+SQLITE_API int sqlite3_open_v2(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb,         /* OUT: SQLite db handle */
+  int flags,              /* Flags */
+  const char *zVfs        /* Name of VFS module to use */
+){
+  return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Open a new database handle.
+*/
+SQLITE_API int sqlite3_open16(
+  const void *zFilename,
+  sqlite3 **ppDb
+){
+  char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
+  sqlite3_value *pVal;
+  int rc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  *ppDb = 0;
+#ifndef SQLITE_OMIT_AUTOINIT
+  rc = sqlite3_initialize();
+  if( rc ) return rc;
+#endif
+  if( zFilename==0 ) zFilename = "\000\000";
+  pVal = sqlite3ValueNew(0);
+  sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
+  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
+  if( zFilename8 ){
+    rc = openDatabase(zFilename8, ppDb,
+                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
+    assert( *ppDb || rc==SQLITE_NOMEM );
+    if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
+      SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
+    }
+  }else{
+    rc = SQLITE_NOMEM_BKPT;
+  }
+  sqlite3ValueFree(pVal);
+
+  return rc & 0xff;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Register a new collation sequence with the database handle db.
+*/
+SQLITE_API int sqlite3_create_collation(
+  sqlite3* db,
+  const char *zName,
+  int enc,
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+){
+  return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
+}
+
+/*
+** Register a new collation sequence with the database handle db.
+*/
+SQLITE_API int sqlite3_create_collation_v2(
+  sqlite3* db,
+  const char *zName,
+  int enc,
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDel)(void*)
+){
+  int rc;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Register a new collation sequence with the database handle db.
+*/
+SQLITE_API int sqlite3_create_collation16(
+  sqlite3* db,
+  const void *zName,
+  int enc,
+  void* pCtx,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+){
+  int rc = SQLITE_OK;
+  char *zName8;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  assert( !db->mallocFailed );
+  zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
+  if( zName8 ){
+    rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
+    sqlite3DbFree(db, zName8);
+  }
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Register a collation sequence factory callback with the database handle
+** db. Replace any previously installed collation sequence factory.
+*/
+SQLITE_API int sqlite3_collation_needed(
+  sqlite3 *db,
+  void *pCollNeededArg,
+  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->xCollNeeded = xCollNeeded;
+  db->xCollNeeded16 = 0;
+  db->pCollNeededArg = pCollNeededArg;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+#ifndef SQLITE_OMIT_UTF16
+/*
+** Register a collation sequence factory callback with the database handle
+** db. Replace any previously installed collation sequence factory.
+*/
+SQLITE_API int sqlite3_collation_needed16(
+  sqlite3 *db,
+  void *pCollNeededArg,
+  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
+){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->xCollNeeded = 0;
+  db->xCollNeeded16 = xCollNeeded16;
+  db->pCollNeededArg = pCollNeededArg;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_UTF16 */
+
+/*
+** Find existing client data.
+*/
+SQLITE_API void *sqlite3_get_clientdata(sqlite3 *db, const char *zName){
+  DbClientData *p;
+  sqlite3_mutex_enter(db->mutex);
+  for(p=db->pDbData; p; p=p->pNext){
+    if( strcmp(p->zName, zName)==0 ){
+      void *pResult = p->pData;
+      sqlite3_mutex_leave(db->mutex);
+      return pResult;
+    }
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return 0;
+}
+
+/*
+** Add new client data to a database connection.
+*/
+SQLITE_API int sqlite3_set_clientdata(
+  sqlite3 *db,                   /* Attach client data to this connection */
+  const char *zName,             /* Name of the client data */
+  void *pData,                   /* The client data itself */
+  void (*xDestructor)(void*)     /* Destructor */
+){
+  DbClientData *p, **pp;
+  sqlite3_mutex_enter(db->mutex);
+  pp = &db->pDbData;
+  for(p=db->pDbData; p && strcmp(p->zName,zName); p=p->pNext){
+    pp = &p->pNext;
+  }
+  if( p ){
+    assert( p->pData!=0 );
+    if( p->xDestructor ) p->xDestructor(p->pData);
+    if( pData==0 ){
+      *pp = p->pNext;
+      sqlite3_free(p);
+      sqlite3_mutex_leave(db->mutex);
+      return SQLITE_OK;
+    }
+  }else if( pData==0 ){
+    sqlite3_mutex_leave(db->mutex);
+    return SQLITE_OK;
+  }else{
+    size_t n = strlen(zName);
+    p = sqlite3_malloc64( sizeof(DbClientData)+n+1 );
+    if( p==0 ){
+      if( xDestructor ) xDestructor(pData);
+      sqlite3_mutex_leave(db->mutex);
+      return SQLITE_NOMEM;
+    }
+    memcpy(p->zName, zName, n+1);
+    p->pNext = db->pDbData;
+    db->pDbData = p;
+  }
+  p->pData = pData;
+  p->xDestructor = xDestructor;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** This function is now an anachronism. It used to be used to recover from a
+** malloc() failure, but SQLite now does this automatically.
+*/
+SQLITE_API int sqlite3_global_recover(void){
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Test to see whether or not the database connection is in autocommit
+** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
+** by default.  Autocommit is disabled by a BEGIN statement and reenabled
+** by the next COMMIT or ROLLBACK.
+*/
+SQLITE_API int sqlite3_get_autocommit(sqlite3 *db){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  return db->autoCommit;
+}
+
+/*
+** The following routines are substitutes for constants SQLITE_CORRUPT,
+** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
+** constants.  They serve two purposes:
+**
+**   1.  Serve as a convenient place to set a breakpoint in a debugger
+**       to detect when version error conditions occurs.
+**
+**   2.  Invoke sqlite3_log() to provide the source code location where
+**       a low-level error is first detected.
+*/
+SQLITE_PRIVATE int sqlite3ReportError(int iErr, int lineno, const char *zType){
+  sqlite3_log(iErr, "%s at line %d of [%.10s]",
+              zType, lineno, 20+sqlite3_sourceid());
+  return iErr;
+}
+SQLITE_PRIVATE int sqlite3CorruptError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_CORRUPT, lineno, "database corruption");
+}
+SQLITE_PRIVATE int sqlite3MisuseError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_MISUSE, lineno, "misuse");
+}
+SQLITE_PRIVATE int sqlite3CantopenError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_CANTOPEN, lineno, "cannot open file");
+}
+#if defined(SQLITE_DEBUG) || defined(SQLITE_ENABLE_CORRUPT_PGNO)
+SQLITE_PRIVATE int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
+  char zMsg[100];
+  sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_CORRUPT, lineno, zMsg);
+}
+#endif
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3NomemError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_NOMEM, lineno, "OOM");
+}
+SQLITE_PRIVATE int sqlite3IoerrnomemError(int lineno){
+  testcase( sqlite3GlobalConfig.xLog!=0 );
+  return sqlite3ReportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
+}
+#endif
+
+#ifndef SQLITE_OMIT_DEPRECATED
+/*
+** This is a convenience routine that makes sure that all thread-specific
+** data for this thread has been deallocated.
+**
+** SQLite no longer uses thread-specific data so this routine is now a
+** no-op.  It is retained for historical compatibility.
+*/
+SQLITE_API void sqlite3_thread_cleanup(void){
+}
+#endif
+
+/*
+** Return meta information about a specific column of a database table.
+** See comment in sqlite3.h (sqlite.h.in) for details.
+*/
+SQLITE_API int sqlite3_table_column_metadata(
+  sqlite3 *db,                /* Connection handle */
+  const char *zDbName,        /* Database name or NULL */
+  const char *zTableName,     /* Table name */
+  const char *zColumnName,    /* Column name */
+  char const **pzDataType,    /* OUTPUT: Declared data type */
+  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
+  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
+  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
+  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
+){
+  int rc;
+  char *zErrMsg = 0;
+  Table *pTab = 0;
+  Column *pCol = 0;
+  int iCol = 0;
+  char const *zDataType = 0;
+  char const *zCollSeq = 0;
+  int notnull = 0;
+  int primarykey = 0;
+  int autoinc = 0;
+
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+
+  /* Ensure the database schema has been loaded */
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  rc = sqlite3Init(db, &zErrMsg);
+  if( SQLITE_OK!=rc ){
+    goto error_out;
+  }
+
+  /* Locate the table in question */
+  pTab = sqlite3FindTable(db, zTableName, zDbName);
+  if( !pTab || IsView(pTab) ){
+    pTab = 0;
+    goto error_out;
+  }
+
+  /* Find the column for which info is requested */
+  if( zColumnName==0 ){
+    /* Query for existence of table only */
+  }else{
+    for(iCol=0; iCol<pTab->nCol; iCol++){
+      pCol = &pTab->aCol[iCol];
+      if( 0==sqlite3StrICmp(pCol->zCnName, zColumnName) ){
+        break;
+      }
+    }
+    if( iCol==pTab->nCol ){
+      if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
+        iCol = pTab->iPKey;
+        pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
+      }else{
+        pTab = 0;
+        goto error_out;
+      }
+    }
+  }
+
+  /* The following block stores the meta information that will be returned
+  ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
+  ** and autoinc. At this point there are two possibilities:
+  **
+  **     1. The specified column name was rowid", "oid" or "_rowid_"
+  **        and there is no explicitly declared IPK column.
+  **
+  **     2. The table is not a view and the column name identified an
+  **        explicitly declared column. Copy meta information from *pCol.
+  */
+  if( pCol ){
+    zDataType = sqlite3ColumnType(pCol,0);
+    zCollSeq = sqlite3ColumnColl(pCol);
+    notnull = pCol->notNull!=0;
+    primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
+    autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
+  }else{
+    zDataType = "INTEGER";
+    primarykey = 1;
+  }
+  if( !zCollSeq ){
+    zCollSeq = sqlite3StrBINARY;
+  }
+
+error_out:
+  sqlite3BtreeLeaveAll(db);
+
+  /* Whether the function call succeeded or failed, set the output parameters
+  ** to whatever their local counterparts contain. If an error did occur,
+  ** this has the effect of zeroing all output parameters.
+  */
+  if( pzDataType ) *pzDataType = zDataType;
+  if( pzCollSeq ) *pzCollSeq = zCollSeq;
+  if( pNotNull ) *pNotNull = notnull;
+  if( pPrimaryKey ) *pPrimaryKey = primarykey;
+  if( pAutoinc ) *pAutoinc = autoinc;
+
+  if( SQLITE_OK==rc && !pTab ){
+    sqlite3DbFree(db, zErrMsg);
+    zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
+        zColumnName);
+    rc = SQLITE_ERROR;
+  }
+  sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
+  sqlite3DbFree(db, zErrMsg);
+  rc = sqlite3ApiExit(db, rc);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Sleep for a little while.  Return the amount of time slept.
+*/
+SQLITE_API int sqlite3_sleep(int ms){
+  sqlite3_vfs *pVfs;
+  int rc;
+  pVfs = sqlite3_vfs_find(0);
+  if( pVfs==0 ) return 0;
+
+  /* This function works in milliseconds, but the underlying OsSleep()
+  ** API uses microseconds. Hence the 1000's.
+  */
+  rc = (sqlite3OsSleep(pVfs, ms<0 ? 0 : 1000*ms)/1000);
+  return rc;
+}
+
+/*
+** Enable or disable the extended result codes.
+*/
+SQLITE_API int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  db->errMask = onoff ? 0xffffffff : 0xff;
+  sqlite3_mutex_leave(db->mutex);
+  return SQLITE_OK;
+}
+
+/*
+** Invoke the xFileControl method on a particular database.
+*/
+SQLITE_API int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
+  int rc = SQLITE_ERROR;
+  Btree *pBtree;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  pBtree = sqlite3DbNameToBtree(db, zDbName);
+  if( pBtree ){
+    Pager *pPager;
+    sqlite3_file *fd;
+    sqlite3BtreeEnter(pBtree);
+    pPager = sqlite3BtreePager(pBtree);
+    assert( pPager!=0 );
+    fd = sqlite3PagerFile(pPager);
+    assert( fd!=0 );
+    if( op==SQLITE_FCNTL_FILE_POINTER ){
+      *(sqlite3_file**)pArg = fd;
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_VFS_POINTER ){
+      *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
+      *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_DATA_VERSION ){
+      *(unsigned int*)pArg = sqlite3PagerDataVersion(pPager);
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_RESERVE_BYTES ){
+      int iNew = *(int*)pArg;
+      *(int*)pArg = sqlite3BtreeGetRequestedReserve(pBtree);
+      if( iNew>=0 && iNew<=255 ){
+        sqlite3BtreeSetPageSize(pBtree, 0, iNew, 0);
+      }
+      rc = SQLITE_OK;
+    }else if( op==SQLITE_FCNTL_RESET_CACHE ){
+      sqlite3BtreeClearCache(pBtree);
+      rc = SQLITE_OK;
+    }else{
+      int nSave = db->busyHandler.nBusy;
+      rc = sqlite3OsFileControl(fd, op, pArg);
+      db->busyHandler.nBusy = nSave;
+    }
+    sqlite3BtreeLeave(pBtree);
+  }
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Interface to the testing logic.
+*/
+SQLITE_API int sqlite3_test_control(int op, ...){
+  int rc = 0;
+#ifdef SQLITE_UNTESTABLE
+  UNUSED_PARAMETER(op);
+#else
+  va_list ap;
+  va_start(ap, op);
+  switch( op ){
+
+    /*
+    ** Save the current state of the PRNG.
+    */
+    case SQLITE_TESTCTRL_PRNG_SAVE: {
+      sqlite3PrngSaveState();
+      break;
+    }
+
+    /*
+    ** Restore the state of the PRNG to the last state saved using
+    ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
+    ** this verb acts like PRNG_RESET.
+    */
+    case SQLITE_TESTCTRL_PRNG_RESTORE: {
+      sqlite3PrngRestoreState();
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_PRNG_SEED, int x, sqlite3 *db);
+    **
+    ** Control the seed for the pseudo-random number generator (PRNG) that
+    ** is built into SQLite.  Cases:
+    **
+    **    x!=0 && db!=0       Seed the PRNG to the current value of the
+    **                        schema cookie in the main database for db, or
+    **                        x if the schema cookie is zero.  This case
+    **                        is convenient to use with database fuzzers
+    **                        as it allows the fuzzer some control over the
+    **                        the PRNG seed.
+    **
+    **    x!=0 && db==0       Seed the PRNG to the value of x.
+    **
+    **    x==0 && db==0       Revert to default behavior of using the
+    **                        xRandomness method on the primary VFS.
+    **
+    ** This test-control also resets the PRNG so that the new seed will
+    ** be used for the next call to sqlite3_randomness().
+    */
+#ifndef SQLITE_OMIT_WSD
+    case SQLITE_TESTCTRL_PRNG_SEED: {
+      int x = va_arg(ap, int);
+      int y;
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      assert( db==0 || db->aDb[0].pSchema!=0 );
+      if( db && (y = db->aDb[0].pSchema->schema_cookie)!=0 ){ x = y; }
+      sqlite3Config.iPrngSeed = x;
+      sqlite3_randomness(0,0);
+      break;
+    }
+#endif
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_FK_NO_ACTION, sqlite3 *db, int b);
+    **
+    ** If b is true, then activate the SQLITE_FkNoAction setting.  If b is
+    ** false then clearn that setting.  If the SQLITE_FkNoAction setting is
+    ** abled, all foreign key ON DELETE and ON UPDATE actions behave as if
+    ** they were NO ACTION, regardless of how they are defined.
+    **
+    ** NB:  One must usually run "PRAGMA writable_schema=RESET" after
+    ** using this test-control, before it will take full effect.  failing
+    ** to reset the schema can result in some unexpected behavior.
+    */
+    case SQLITE_TESTCTRL_FK_NO_ACTION: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      int b = va_arg(ap, int);
+      if( b ){
+        db->flags |= SQLITE_FkNoAction;
+      }else{
+        db->flags &= ~SQLITE_FkNoAction;
+      }
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(BITVEC_TEST, size, program)
+    **
+    ** Run a test against a Bitvec object of size.  The program argument
+    ** is an array of integers that defines the test.  Return -1 on a
+    ** memory allocation error, 0 on success, or non-zero for an error.
+    ** See the sqlite3BitvecBuiltinTest() for additional information.
+    */
+    case SQLITE_TESTCTRL_BITVEC_TEST: {
+      int sz = va_arg(ap, int);
+      int *aProg = va_arg(ap, int*);
+      rc = sqlite3BitvecBuiltinTest(sz, aProg);
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(FAULT_INSTALL, xCallback)
+    **
+    ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
+    ** if xCallback is not NULL.
+    **
+    ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
+    ** is called immediately after installing the new callback and the return
+    ** value from sqlite3FaultSim(0) becomes the return from
+    ** sqlite3_test_control().
+    */
+    case SQLITE_TESTCTRL_FAULT_INSTALL: {
+      /* A bug in MSVC prevents it from understanding pointers to functions
+      ** types in the second argument to va_arg().  Work around the problem
+      ** using a typedef.
+      ** http://support.microsoft.com/kb/47961  <-- dead hyperlink
+      ** Search at http://web.archive.org/ to find the 2015-03-16 archive
+      ** of the link above to see the original text.
+      ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
+      */
+      typedef int(*sqlite3FaultFuncType)(int);
+      sqlite3GlobalConfig.xTestCallback = va_arg(ap, sqlite3FaultFuncType);
+      rc = sqlite3FaultSim(0);
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
+    **
+    ** Register hooks to call to indicate which malloc() failures
+    ** are benign.
+    */
+    case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
+      typedef void (*void_function)(void);
+      void_function xBenignBegin;
+      void_function xBenignEnd;
+      xBenignBegin = va_arg(ap, void_function);
+      xBenignEnd = va_arg(ap, void_function);
+      sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
+    **
+    ** Set the PENDING byte to the value in the argument, if X>0.
+    ** Make no changes if X==0.  Return the value of the pending byte
+    ** as it existing before this routine was called.
+    **
+    ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
+    ** an incompatible database file format.  Changing the PENDING byte
+    ** while any database connection is open results in undefined and
+    ** deleterious behavior.
+    */
+    case SQLITE_TESTCTRL_PENDING_BYTE: {
+      rc = PENDING_BYTE;
+#ifndef SQLITE_OMIT_WSD
+      {
+        unsigned int newVal = va_arg(ap, unsigned int);
+        if( newVal ) sqlite3PendingByte = newVal;
+      }
+#endif
+      break;
+    }
+
+    /*
+    **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
+    **
+    ** This action provides a run-time test to see whether or not
+    ** assert() was enabled at compile-time.  If X is true and assert()
+    ** is enabled, then the return value is true.  If X is true and
+    ** assert() is disabled, then the return value is zero.  If X is
+    ** false and assert() is enabled, then the assertion fires and the
+    ** process aborts.  If X is false and assert() is disabled, then the
+    ** return value is zero.
+    */
+    case SQLITE_TESTCTRL_ASSERT: {
+      volatile int x = 0;
+      assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
+      rc = x;
+#if defined(SQLITE_DEBUG)
+      /* Invoke these debugging routines so that the compiler does not
+      ** issue "defined but not used" warnings. */
+      if( x==9999 ){
+        sqlite3ShowExpr(0);
+        sqlite3ShowExprList(0);
+        sqlite3ShowIdList(0);
+        sqlite3ShowSrcList(0);
+        sqlite3ShowWith(0);
+        sqlite3ShowUpsert(0);
+#ifndef SQLITE_OMIT_TRIGGER
+        sqlite3ShowTriggerStep(0);
+        sqlite3ShowTriggerStepList(0);
+        sqlite3ShowTrigger(0);
+        sqlite3ShowTriggerList(0);
+#endif
+#ifndef SQLITE_OMIT_WINDOWFUNC
+        sqlite3ShowWindow(0);
+        sqlite3ShowWinFunc(0);
+#endif
+        sqlite3ShowSelect(0);
+      }
+#endif
+      break;
+    }
+
+
+    /*
+    **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
+    **
+    ** This action provides a run-time test to see how the ALWAYS and
+    ** NEVER macros were defined at compile-time.
+    **
+    ** The return value is ALWAYS(X) if X is true, or 0 if X is false.
+    **
+    ** The recommended test is X==2.  If the return value is 2, that means
+    ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
+    ** default setting.  If the return value is 1, then ALWAYS() is either
+    ** hard-coded to true or else it asserts if its argument is false.
+    ** The first behavior (hard-coded to true) is the case if
+    ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
+    ** behavior (assert if the argument to ALWAYS() is false) is the case if
+    ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
+    **
+    ** The run-time test procedure might look something like this:
+    **
+    **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
+    **      // ALWAYS() and NEVER() are no-op pass-through macros
+    **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
+    **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
+    **    }else{
+    **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
+    **    }
+    */
+    case SQLITE_TESTCTRL_ALWAYS: {
+      int x = va_arg(ap,int);
+      rc = x ? ALWAYS(x) : 0;
+      break;
+    }
+
+    /*
+    **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
+    **
+    ** The integer returned reveals the byte-order of the computer on which
+    ** SQLite is running:
+    **
+    **       1     big-endian,    determined at run-time
+    **      10     little-endian, determined at run-time
+    **  432101     big-endian,    determined at compile-time
+    **  123410     little-endian, determined at compile-time
+    */
+    case SQLITE_TESTCTRL_BYTEORDER: {
+      rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
+    **
+    ** Enable or disable various optimizations for testing purposes.  The
+    ** argument N is a bitmask of optimizations to be disabled.  For normal
+    ** operation N should be 0.  The idea is that a test program (like the
+    ** SQL Logic Test or SLT test module) can run the same SQL multiple times
+    ** with various optimizations disabled to verify that the same answer
+    ** is obtained in every case.
+    */
+    case SQLITE_TESTCTRL_OPTIMIZATIONS: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      db->dbOptFlags = va_arg(ap, u32);
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_GETOPT, sqlite3 *db, int *N)
+    **
+    ** Write the current optimization settings into *N.  A zero bit means that
+    ** the optimization is on, and a 1 bit means that the optimization is off.
+    */
+    case SQLITE_TESTCTRL_GETOPT: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      int *pN = va_arg(ap, int*);
+      *pN = db->dbOptFlags;
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, onoff, xAlt);
+    **
+    ** If parameter onoff is 1, subsequent calls to localtime() fail.
+    ** If 2, then invoke xAlt() instead of localtime().  If 0, normal
+    ** processing.
+    **
+    ** xAlt arguments are void pointers, but they really want to be:
+    **
+    **    int xAlt(const time_t*, struct tm*);
+    **
+    ** xAlt should write results in to struct tm object of its 2nd argument
+    ** and return zero on success, or return non-zero on failure.
+    */
+    case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
+      sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
+      if( sqlite3GlobalConfig.bLocaltimeFault==2 ){
+        typedef int(*sqlite3LocaltimeType)(const void*,void*);
+        sqlite3GlobalConfig.xAltLocaltime = va_arg(ap, sqlite3LocaltimeType);
+      }else{
+        sqlite3GlobalConfig.xAltLocaltime = 0;
+      }
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_INTERNAL_FUNCTIONS, sqlite3*);
+    **
+    ** Toggle the ability to use internal functions on or off for
+    ** the database connection given in the argument.
+    */
+    case SQLITE_TESTCTRL_INTERNAL_FUNCTIONS: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      db->mDbFlags ^= DBFLAG_InternalFunc;
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
+    **
+    ** Set or clear a flag that indicates that the database file is always well-
+    ** formed and never corrupt.  This flag is clear by default, indicating that
+    ** database files might have arbitrary corruption.  Setting the flag during
+    ** testing causes certain assert() statements in the code to be activated
+    ** that demonstrate invariants on well-formed database files.
+    */
+    case SQLITE_TESTCTRL_NEVER_CORRUPT: {
+      sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS, int);
+    **
+    ** Set or clear a flag that causes SQLite to verify that type, name,
+    ** and tbl_name fields of the sqlite_schema table.  This is normally
+    ** on, but it is sometimes useful to turn it off for testing.
+    **
+    ** 2020-07-22:  Disabling EXTRA_SCHEMA_CHECKS also disables the
+    ** verification of rootpage numbers when parsing the schema.  This
+    ** is useful to make it easier to reach strange internal error states
+    ** during testing.  The EXTRA_SCHEMA_CHECKS setting is always enabled
+    ** in production.
+    */
+    case SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS: {
+      sqlite3GlobalConfig.bExtraSchemaChecks = va_arg(ap, int);
+      break;
+    }
+
+    /* Set the threshold at which OP_Once counters reset back to zero.
+    ** By default this is 0x7ffffffe (over 2 billion), but that value is
+    ** too big to test in a reasonable amount of time, so this control is
+    ** provided to set a small and easily reachable reset value.
+    */
+    case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
+      sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
+    **
+    ** Set the VDBE coverage callback function to xCallback with context
+    ** pointer ptr.
+    */
+    case SQLITE_TESTCTRL_VDBE_COVERAGE: {
+#ifdef SQLITE_VDBE_COVERAGE
+      typedef void (*branch_callback)(void*,unsigned int,
+                                      unsigned char,unsigned char);
+      sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
+      sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
+#endif
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
+    case SQLITE_TESTCTRL_SORTER_MMAP: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      db->nMaxSorterMmap = va_arg(ap, int);
+      break;
+    }
+
+    /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
+    **
+    ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
+    ** not.
+    */
+    case SQLITE_TESTCTRL_ISINIT: {
+      if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
+    **
+    ** This test control is used to create imposter tables.  "db" is a pointer
+    ** to the database connection.  dbName is the database name (ex: "main" or
+    ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
+    ** or off.  "tnum" is the root page of the b-tree to which the imposter
+    ** table should connect.
+    **
+    ** Enable imposter mode only when the schema has already been parsed.  Then
+    ** run a single CREATE TABLE statement to construct the imposter table in
+    ** the parsed schema.  Then turn imposter mode back off again.
+    **
+    ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
+    ** the schema to be reparsed the next time it is needed.  This has the
+    ** effect of erasing all imposter tables.
+    */
+    case SQLITE_TESTCTRL_IMPOSTER: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      int iDb;
+      sqlite3_mutex_enter(db->mutex);
+      iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
+      if( iDb>=0 ){
+        db->init.iDb = iDb;
+        db->init.busy = db->init.imposterTable = va_arg(ap,int);
+        db->init.newTnum = va_arg(ap,int);
+        if( db->init.busy==0 && db->init.newTnum>0 ){
+          sqlite3ResetAllSchemasOfConnection(db);
+        }
+      }
+      sqlite3_mutex_leave(db->mutex);
+      break;
+    }
+
+#if defined(YYCOVERAGE)
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_PARSER_COVERAGE, FILE *out)
+    **
+    ** This test control (only available when SQLite is compiled with
+    ** -DYYCOVERAGE) writes a report onto "out" that shows all
+    ** state/lookahead combinations in the parser state machine
+    ** which are never exercised.  If any state is missed, make the
+    ** return code SQLITE_ERROR.
+    */
+    case SQLITE_TESTCTRL_PARSER_COVERAGE: {
+      FILE *out = va_arg(ap, FILE*);
+      if( sqlite3ParserCoverage(out) ) rc = SQLITE_ERROR;
+      break;
+    }
+#endif /* defined(YYCOVERAGE) */
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_RESULT_INTREAL, sqlite3_context*);
+    **
+    ** This test-control causes the most recent sqlite3_result_int64() value
+    ** to be interpreted as a MEM_IntReal instead of as an MEM_Int.  Normally,
+    ** MEM_IntReal values only arise during an INSERT operation of integer
+    ** values into a REAL column, so they can be challenging to test.  This
+    ** test-control enables us to write an intreal() SQL function that can
+    ** inject an intreal() value at arbitrary places in an SQL statement,
+    ** for testing purposes.
+    */
+    case SQLITE_TESTCTRL_RESULT_INTREAL: {
+      sqlite3_context *pCtx = va_arg(ap, sqlite3_context*);
+      sqlite3ResultIntReal(pCtx);
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_SEEK_COUNT,
+    **    sqlite3 *db,    // Database connection
+    **    u64 *pnSeek     // Write seek count here
+    **  );
+    **
+    ** This test-control queries the seek-counter on the "main" database
+    ** file.  The seek-counter is written into *pnSeek and is then reset.
+    ** The seek-count is only available if compiled with SQLITE_DEBUG.
+    */
+    case SQLITE_TESTCTRL_SEEK_COUNT: {
+      sqlite3 *db = va_arg(ap, sqlite3*);
+      u64 *pn = va_arg(ap, sqlite3_uint64*);
+      *pn = sqlite3BtreeSeekCount(db->aDb->pBt);
+      (void)db;  /* Silence harmless unused variable warning */
+      break;
+    }
+
+    /*  sqlite3_test_control(SQLITE_TESTCTRL_TRACEFLAGS, op, ptr)
+    **
+    **  "ptr" is a pointer to a u32.
+    **
+    **   op==0       Store the current sqlite3TreeTrace in *ptr
+    **   op==1       Set sqlite3TreeTrace to the value *ptr
+    **   op==2       Store the current sqlite3WhereTrace in *ptr
+    **   op==3       Set sqlite3WhereTrace to the value *ptr
+    */
+    case SQLITE_TESTCTRL_TRACEFLAGS: {
+       int opTrace = va_arg(ap, int);
+       u32 *ptr = va_arg(ap, u32*);
+       switch( opTrace ){
+         case 0:   *ptr = sqlite3TreeTrace;      break;
+         case 1:   sqlite3TreeTrace = *ptr;      break;
+         case 2:   *ptr = sqlite3WhereTrace;     break;
+         case 3:   sqlite3WhereTrace = *ptr;     break;
+       }
+       break;
+    }
+
+    /* sqlite3_test_control(SQLITE_TESTCTRL_LOGEST,
+    **      double fIn,     // Input value
+    **      int *pLogEst,   // sqlite3LogEstFromDouble(fIn)
+    **      u64 *pInt,      // sqlite3LogEstToInt(*pLogEst)
+    **      int *pLogEst2   // sqlite3LogEst(*pInt)
+    ** );
+    **
+    ** Test access for the LogEst conversion routines.
+    */
+    case SQLITE_TESTCTRL_LOGEST: {
+      double rIn = va_arg(ap, double);
+      LogEst rLogEst = sqlite3LogEstFromDouble(rIn);
+      int *pI1 = va_arg(ap,int*);
+      u64 *pU64 = va_arg(ap,u64*);
+      int *pI2 = va_arg(ap,int*);
+      *pI1 = rLogEst;
+      *pU64 = sqlite3LogEstToInt(rLogEst);
+      *pI2 = sqlite3LogEst(*pU64);
+      break;
+    }
+
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_WSD)
+    /* sqlite3_test_control(SQLITE_TESTCTRL_TUNE, id, *piValue)
+    **
+    ** If "id" is an integer between 1 and SQLITE_NTUNE then set the value
+    ** of the id-th tuning parameter to *piValue.  If "id" is between -1
+    ** and -SQLITE_NTUNE, then write the current value of the (-id)-th
+    ** tuning parameter into *piValue.
+    **
+    ** Tuning parameters are for use during transient development builds,
+    ** to help find the best values for constants in the query planner.
+    ** Access tuning parameters using the Tuning(ID) macro.  Set the
+    ** parameters in the CLI using ".testctrl tune ID VALUE".
+    **
+    ** Transient use only.  Tuning parameters should not be used in
+    ** checked-in code.
+    */
+    case SQLITE_TESTCTRL_TUNE: {
+      int id = va_arg(ap, int);
+      int *piValue = va_arg(ap, int*);
+      if( id>0 && id<=SQLITE_NTUNE ){
+        Tuning(id) = *piValue;
+      }else if( id<0 && id>=-SQLITE_NTUNE ){
+        *piValue = Tuning(-id);
+      }else{
+        rc = SQLITE_NOTFOUND;
+      }
+      break;
+    }
+#endif
+
+    /* sqlite3_test_control(SQLITE_TESTCTRL_JSON_SELFCHECK, &onOff);
+    **
+    ** Activate or deactivate validation of JSONB that is generated from
+    ** text.  Off by default, as the validation is slow.  Validation is
+    ** only available if compiled using SQLITE_DEBUG.
+    **
+    ** If onOff is initially 1, then turn it on.  If onOff is initially
+    ** off, turn it off.  If onOff is initially -1, then change onOff
+    ** to be the current setting.
+    */
+    case SQLITE_TESTCTRL_JSON_SELFCHECK: {
+#if defined(SQLITE_DEBUG) && !defined(SQLITE_OMIT_WSD)
+      int *pOnOff = va_arg(ap, int*);
+      if( *pOnOff<0 ){
+        *pOnOff = sqlite3Config.bJsonSelfcheck;
+      }else{
+        sqlite3Config.bJsonSelfcheck = (u8)((*pOnOff)&0xff);
+      }
+#endif
+      break;
+    }
+  }
+  va_end(ap);
+#endif /* SQLITE_UNTESTABLE */
+  return rc;
+}
+
+/*
+** The Pager stores the Database filename, Journal filename, and WAL filename
+** consecutively in memory, in that order.  The database filename is prefixed
+** by four zero bytes.  Locate the start of the database filename by searching
+** backwards for the first byte following four consecutive zero bytes.
+**
+** This only works if the filename passed in was obtained from the Pager.
+*/
+static const char *databaseName(const char *zName){
+  while( zName[-1]!=0 || zName[-2]!=0 || zName[-3]!=0 || zName[-4]!=0 ){
+    zName--;
+  }
+  return zName;
+}
+
+/*
+** Append text z[] to the end of p[].  Return a pointer to the first
+** character after then zero terminator on the new text in p[].
+*/
+static char *appendText(char *p, const char *z){
+  size_t n = strlen(z);
+  memcpy(p, z, n+1);
+  return p+n+1;
+}
+
+/*
+** Allocate memory to hold names for a database, journal file, WAL file,
+** and query parameters.  The pointer returned is valid for use by
+** sqlite3_filename_database() and sqlite3_uri_parameter() and related
+** functions.
+**
+** Memory layout must be compatible with that generated by the pager
+** and expected by sqlite3_uri_parameter() and databaseName().
+*/
+SQLITE_API const char *sqlite3_create_filename(
+  const char *zDatabase,
+  const char *zJournal,
+  const char *zWal,
+  int nParam,
+  const char **azParam
+){
+  sqlite3_int64 nByte;
+  int i;
+  char *pResult, *p;
+  nByte = strlen(zDatabase) + strlen(zJournal) + strlen(zWal) + 10;
+  for(i=0; i<nParam*2; i++){
+    nByte += strlen(azParam[i])+1;
+  }
+  pResult = p = sqlite3_malloc64( nByte );
+  if( p==0 ) return 0;
+  memset(p, 0, 4);
+  p += 4;
+  p = appendText(p, zDatabase);
+  for(i=0; i<nParam*2; i++){
+    p = appendText(p, azParam[i]);
+  }
+  *(p++) = 0;
+  p = appendText(p, zJournal);
+  p = appendText(p, zWal);
+  *(p++) = 0;
+  *(p++) = 0;
+  assert( (sqlite3_int64)(p - pResult)==nByte );
+  return pResult + 4;
+}
+
+/*
+** Free memory obtained from sqlite3_create_filename().  It is a severe
+** error to call this routine with any parameter other than a pointer
+** previously obtained from sqlite3_create_filename() or a NULL pointer.
+*/
+SQLITE_API void sqlite3_free_filename(const char *p){
+  if( p==0 ) return;
+  p = databaseName(p);
+  sqlite3_free((char*)p - 4);
+}
+
+
+/*
+** This is a utility routine, useful to VFS implementations, that checks
+** to see if a database file was a URI that contained a specific query
+** parameter, and if so obtains the value of the query parameter.
+**
+** The zFilename argument is the filename pointer passed into the xOpen()
+** method of a VFS implementation.  The zParam argument is the name of the
+** query parameter we seek.  This routine returns the value of the zParam
+** parameter if it exists.  If the parameter does not exist, this routine
+** returns a NULL pointer.
+*/
+SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
+  if( zFilename==0 || zParam==0 ) return 0;
+  zFilename = databaseName(zFilename);
+  return uriParameter(zFilename, zParam);
+}
+
+/*
+** Return a pointer to the name of Nth query parameter of the filename.
+*/
+SQLITE_API const char *sqlite3_uri_key(const char *zFilename, int N){
+  if( zFilename==0 || N<0 ) return 0;
+  zFilename = databaseName(zFilename);
+  zFilename += sqlite3Strlen30(zFilename) + 1;
+  while( ALWAYS(zFilename) && zFilename[0] && (N--)>0 ){
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+  }
+  return zFilename[0] ? zFilename : 0;
+}
+
+/*
+** Return a boolean value for a query parameter.
+*/
+SQLITE_API int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
+  const char *z = sqlite3_uri_parameter(zFilename, zParam);
+  bDflt = bDflt!=0;
+  return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
+}
+
+/*
+** Return a 64-bit integer value for a query parameter.
+*/
+SQLITE_API sqlite3_int64 sqlite3_uri_int64(
+  const char *zFilename,    /* Filename as passed to xOpen */
+  const char *zParam,       /* URI parameter sought */
+  sqlite3_int64 bDflt       /* return if parameter is missing */
+){
+  const char *z = sqlite3_uri_parameter(zFilename, zParam);
+  sqlite3_int64 v;
+  if( z && sqlite3DecOrHexToI64(z, &v)==0 ){
+    bDflt = v;
+  }
+  return bDflt;
+}
+
+/*
+** Translate a filename that was handed to a VFS routine into the corresponding
+** database, journal, or WAL file.
+**
+** It is an error to pass this routine a filename string that was not
+** passed into the VFS from the SQLite core.  Doing so is similar to
+** passing free() a pointer that was not obtained from malloc() - it is
+** an error that we cannot easily detect but that will likely cause memory
+** corruption.
+*/
+SQLITE_API const char *sqlite3_filename_database(const char *zFilename){
+  if( zFilename==0 ) return 0;
+  return databaseName(zFilename);
+}
+SQLITE_API const char *sqlite3_filename_journal(const char *zFilename){
+  if( zFilename==0 ) return 0;
+  zFilename = databaseName(zFilename);
+  zFilename += sqlite3Strlen30(zFilename) + 1;
+  while( ALWAYS(zFilename) && zFilename[0] ){
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+    zFilename += sqlite3Strlen30(zFilename) + 1;
+  }
+  return zFilename + 1;
+}
+SQLITE_API const char *sqlite3_filename_wal(const char *zFilename){
+#ifdef SQLITE_OMIT_WAL
+  return 0;
+#else
+  zFilename = sqlite3_filename_journal(zFilename);
+  if( zFilename ) zFilename += sqlite3Strlen30(zFilename) + 1;
+  return zFilename;
+#endif
+}
+
+/*
+** Return the Btree pointer identified by zDbName.  Return NULL if not found.
+*/
+SQLITE_PRIVATE Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
+  int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
+  return iDb<0 ? 0 : db->aDb[iDb].pBt;
+}
+
+/*
+** Return the name of the N-th database schema.  Return NULL if N is out
+** of range.
+*/
+SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N){
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  if( N<0 || N>=db->nDb ){
+    return 0;
+  }else{
+    return db->aDb[N].zDbSName;
+  }
+}
+
+/*
+** Return the filename of the database associated with a database
+** connection.
+*/
+SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
+  Btree *pBt;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+  pBt = sqlite3DbNameToBtree(db, zDbName);
+  return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
+}
+
+/*
+** Return 1 if database is read-only or 0 if read/write.  Return -1 if
+** no such database exists.
+*/
+SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
+  Btree *pBt;
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    (void)SQLITE_MISUSE_BKPT;
+    return -1;
+  }
+#endif
+  pBt = sqlite3DbNameToBtree(db, zDbName);
+  return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
+}
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+/*
+** Obtain a snapshot handle for the snapshot of database zDb currently
+** being read by handle db.
+*/
+SQLITE_API int sqlite3_snapshot_get(
+  sqlite3 *db,
+  const char *zDb,
+  sqlite3_snapshot **ppSnapshot
+){
+  int rc = SQLITE_ERROR;
+#ifndef SQLITE_OMIT_WAL
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+
+  if( db->autoCommit==0 ){
+    int iDb = sqlite3FindDbName(db, zDb);
+    if( iDb==0 || iDb>1 ){
+      Btree *pBt = db->aDb[iDb].pBt;
+      if( SQLITE_TXN_WRITE!=sqlite3BtreeTxnState(pBt) ){
+        Pager *pPager = sqlite3BtreePager(pBt);
+        i64 dummy = 0;
+        sqlite3PagerSnapshotOpen(pPager, (sqlite3_snapshot*)&dummy);
+        rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
+        sqlite3PagerSnapshotOpen(pPager, 0);
+        if( rc==SQLITE_OK ){
+          rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
+        }
+      }
+    }
+  }
+
+  sqlite3_mutex_leave(db->mutex);
+#endif   /* SQLITE_OMIT_WAL */
+  return rc;
+}
+
+/*
+** Open a read-transaction on the snapshot identified by pSnapshot.
+*/
+SQLITE_API int sqlite3_snapshot_open(
+  sqlite3 *db,
+  const char *zDb,
+  sqlite3_snapshot *pSnapshot
+){
+  int rc = SQLITE_ERROR;
+#ifndef SQLITE_OMIT_WAL
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  if( db->autoCommit==0 ){
+    int iDb;
+    iDb = sqlite3FindDbName(db, zDb);
+    if( iDb==0 || iDb>1 ){
+      Btree *pBt = db->aDb[iDb].pBt;
+      if( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_WRITE ){
+        Pager *pPager = sqlite3BtreePager(pBt);
+        int bUnlock = 0;
+        if( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_NONE ){
+          if( db->nVdbeActive==0 ){
+            rc = sqlite3PagerSnapshotCheck(pPager, pSnapshot);
+            if( rc==SQLITE_OK ){
+              bUnlock = 1;
+              rc = sqlite3BtreeCommit(pBt);
+            }
+          }
+        }else{
+          rc = SQLITE_OK;
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3PagerSnapshotOpen(pPager, pSnapshot);
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
+          sqlite3PagerSnapshotOpen(pPager, 0);
+        }
+        if( bUnlock ){
+          sqlite3PagerSnapshotUnlock(pPager);
+        }
+      }
+    }
+  }
+
+  sqlite3_mutex_leave(db->mutex);
+#endif   /* SQLITE_OMIT_WAL */
+  return rc;
+}
+
+/*
+** Recover as many snapshots as possible from the wal file associated with
+** schema zDb of database db.
+*/
+SQLITE_API int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
+  int rc = SQLITE_ERROR;
+#ifndef SQLITE_OMIT_WAL
+  int iDb;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ){
+    return SQLITE_MISUSE_BKPT;
+  }
+#endif
+
+  sqlite3_mutex_enter(db->mutex);
+  iDb = sqlite3FindDbName(db, zDb);
+  if( iDb==0 || iDb>1 ){
+    Btree *pBt = db->aDb[iDb].pBt;
+    if( SQLITE_TXN_NONE==sqlite3BtreeTxnState(pBt) ){
+      rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
+        sqlite3BtreeCommit(pBt);
+      }
+    }
+  }
+  sqlite3_mutex_leave(db->mutex);
+#endif   /* SQLITE_OMIT_WAL */
+  return rc;
+}
+
+/*
+** Free a snapshot handle obtained from sqlite3_snapshot_get().
+*/
+SQLITE_API void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
+  sqlite3_free(pSnapshot);
+}
+#endif /* SQLITE_ENABLE_SNAPSHOT */
+
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+/*
+** Given the name of a compile-time option, return true if that option
+** was used and false if not.
+**
+** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
+** is not required for a match.
+*/
+SQLITE_API int sqlite3_compileoption_used(const char *zOptName){
+  int i, n;
+  int nOpt;
+  const char **azCompileOpt;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( zOptName==0 ){
+    (void)SQLITE_MISUSE_BKPT;
+    return 0;
+  }
+#endif
+
+  azCompileOpt = sqlite3CompileOptions(&nOpt);
+
+  if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
+  n = sqlite3Strlen30(zOptName);
+
+  /* Since nOpt is normally in single digits, a linear search is
+  ** adequate. No need for a binary search. */
+  for(i=0; i<nOpt; i++){
+    if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
+     && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
+    ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+/*
+** Return the N-th compile-time option string.  If N is out of range,
+** return a NULL pointer.
+*/
+SQLITE_API const char *sqlite3_compileoption_get(int N){
+  int nOpt;
+  const char **azCompileOpt;
+  azCompileOpt = sqlite3CompileOptions(&nOpt);
+  if( N>=0 && N<nOpt ){
+    return azCompileOpt[N];
+  }
+  return 0;
+}
+#endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
+
+/************** End of main.c ************************************************/
+/************** Begin file notify.c ******************************************/
+/*
+** 2009 March 3
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the implementation of the sqlite3_unlock_notify()
+** API method and its associated functionality.
+*/
+/* #include "sqliteInt.h" */
+/* #include "btreeInt.h" */
+
+/* Omit this entire file if SQLITE_ENABLE_UNLOCK_NOTIFY is not defined. */
+#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
+
+/*
+** Public interfaces:
+**
+**   sqlite3ConnectionBlocked()
+**   sqlite3ConnectionUnlocked()
+**   sqlite3ConnectionClosed()
+**   sqlite3_unlock_notify()
+*/
+
+#define assertMutexHeld() \
+  assert( sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN)) )
+
+/*
+** Head of a linked list of all sqlite3 objects created by this process
+** for which either sqlite3.pBlockingConnection or sqlite3.pUnlockConnection
+** is not NULL. This variable may only accessed while the STATIC_MAIN
+** mutex is held.
+*/
+static sqlite3 *SQLITE_WSD sqlite3BlockedList = 0;
+
+#ifndef NDEBUG
+/*
+** This function is a complex assert() that verifies the following
+** properties of the blocked connections list:
+**
+**   1) Each entry in the list has a non-NULL value for either
+**      pUnlockConnection or pBlockingConnection, or both.
+**
+**   2) All entries in the list that share a common value for
+**      xUnlockNotify are grouped together.
+**
+**   3) If the argument db is not NULL, then none of the entries in the
+**      blocked connections list have pUnlockConnection or pBlockingConnection
+**      set to db. This is used when closing connection db.
+*/
+static void checkListProperties(sqlite3 *db){
+  sqlite3 *p;
+  for(p=sqlite3BlockedList; p; p=p->pNextBlocked){
+    int seen = 0;
+    sqlite3 *p2;
+
+    /* Verify property (1) */
+    assert( p->pUnlockConnection || p->pBlockingConnection );
+
+    /* Verify property (2) */
+    for(p2=sqlite3BlockedList; p2!=p; p2=p2->pNextBlocked){
+      if( p2->xUnlockNotify==p->xUnlockNotify ) seen = 1;
+      assert( p2->xUnlockNotify==p->xUnlockNotify || !seen );
+      assert( db==0 || p->pUnlockConnection!=db );
+      assert( db==0 || p->pBlockingConnection!=db );
+    }
+  }
+}
+#else
+# define checkListProperties(x)
+#endif
+
+/*
+** Remove connection db from the blocked connections list. If connection
+** db is not currently a part of the list, this function is a no-op.
+*/
+static void removeFromBlockedList(sqlite3 *db){
+  sqlite3 **pp;
+  assertMutexHeld();
+  for(pp=&sqlite3BlockedList; *pp; pp = &(*pp)->pNextBlocked){
+    if( *pp==db ){
+      *pp = (*pp)->pNextBlocked;
+      break;
+    }
+  }
+}
+
+/*
+** Add connection db to the blocked connections list. It is assumed
+** that it is not already a part of the list.
+*/
+static void addToBlockedList(sqlite3 *db){
+  sqlite3 **pp;
+  assertMutexHeld();
+  for(
+    pp=&sqlite3BlockedList;
+    *pp && (*pp)->xUnlockNotify!=db->xUnlockNotify;
+    pp=&(*pp)->pNextBlocked
+  );
+  db->pNextBlocked = *pp;
+  *pp = db;
+}
+
+/*
+** Obtain the STATIC_MAIN mutex.
+*/
+static void enterMutex(void){
+  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN));
+  checkListProperties(0);
+}
+
+/*
+** Release the STATIC_MAIN mutex.
+*/
+static void leaveMutex(void){
+  assertMutexHeld();
+  checkListProperties(0);
+  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN));
+}
+
+/*
+** Register an unlock-notify callback.
+**
+** This is called after connection "db" has attempted some operation
+** but has received an SQLITE_LOCKED error because another connection
+** (call it pOther) in the same process was busy using the same shared
+** cache.  pOther is found by looking at db->pBlockingConnection.
+**
+** If there is no blocking connection, the callback is invoked immediately,
+** before this routine returns.
+**
+** If pOther is already blocked on db, then report SQLITE_LOCKED, to indicate
+** a deadlock.
+**
+** Otherwise, make arrangements to invoke xNotify when pOther drops
+** its locks.
+**
+** Each call to this routine overrides any prior callbacks registered
+** on the same "db".  If xNotify==0 then any prior callbacks are immediately
+** cancelled.
+*/
+SQLITE_API int sqlite3_unlock_notify(
+  sqlite3 *db,
+  void (*xNotify)(void **, int),
+  void *pArg
+){
+  int rc = SQLITE_OK;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+  if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
+#endif
+  sqlite3_mutex_enter(db->mutex);
+  enterMutex();
+
+  if( xNotify==0 ){
+    removeFromBlockedList(db);
+    db->pBlockingConnection = 0;
+    db->pUnlockConnection = 0;
+    db->xUnlockNotify = 0;
+    db->pUnlockArg = 0;
+  }else if( 0==db->pBlockingConnection ){
+    /* The blocking transaction has been concluded. Or there never was a
+    ** blocking transaction. In either case, invoke the notify callback
+    ** immediately.
+    */
+    xNotify(&pArg, 1);
+  }else{
+    sqlite3 *p;
+
+    for(p=db->pBlockingConnection; p && p!=db; p=p->pUnlockConnection){}
+    if( p ){
+      rc = SQLITE_LOCKED;              /* Deadlock detected. */
+    }else{
+      db->pUnlockConnection = db->pBlockingConnection;
+      db->xUnlockNotify = xNotify;
+      db->pUnlockArg = pArg;
+      removeFromBlockedList(db);
+      addToBlockedList(db);
+    }
+  }
+
+  leaveMutex();
+  assert( !db->mallocFailed );
+  sqlite3ErrorWithMsg(db, rc, (rc?"database is deadlocked":0));
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** This function is called while stepping or preparing a statement
+** associated with connection db. The operation will return SQLITE_LOCKED
+** to the user because it requires a lock that will not be available
+** until connection pBlocker concludes its current transaction.
+*/
+SQLITE_PRIVATE void sqlite3ConnectionBlocked(sqlite3 *db, sqlite3 *pBlocker){
+  enterMutex();
+  if( db->pBlockingConnection==0 && db->pUnlockConnection==0 ){
+    addToBlockedList(db);
+  }
+  db->pBlockingConnection = pBlocker;
+  leaveMutex();
+}
+
+/*
+** This function is called when
+** the transaction opened by database db has just finished. Locks held
+** by database connection db have been released.
+**
+** This function loops through each entry in the blocked connections
+** list and does the following:
+**
+**   1) If the sqlite3.pBlockingConnection member of a list entry is
+**      set to db, then set pBlockingConnection=0.
+**
+**   2) If the sqlite3.pUnlockConnection member of a list entry is
+**      set to db, then invoke the configured unlock-notify callback and
+**      set pUnlockConnection=0.
+**
+**   3) If the two steps above mean that pBlockingConnection==0 and
+**      pUnlockConnection==0, remove the entry from the blocked connections
+**      list.
+*/
+SQLITE_PRIVATE void sqlite3ConnectionUnlocked(sqlite3 *db){
+  void (*xUnlockNotify)(void **, int) = 0; /* Unlock-notify cb to invoke */
+  int nArg = 0;                            /* Number of entries in aArg[] */
+  sqlite3 **pp;                            /* Iterator variable */
+  void **aArg;               /* Arguments to the unlock callback */
+  void **aDyn = 0;           /* Dynamically allocated space for aArg[] */
+  void *aStatic[16];         /* Starter space for aArg[].  No malloc required */
+
+  aArg = aStatic;
+  enterMutex();         /* Enter STATIC_MAIN mutex */
+
+  /* This loop runs once for each entry in the blocked-connections list. */
+  for(pp=&sqlite3BlockedList; *pp; /* no-op */ ){
+    sqlite3 *p = *pp;
+
+    /* Step 1. */
+    if( p->pBlockingConnection==db ){
+      p->pBlockingConnection = 0;
+    }
+
+    /* Step 2. */
+    if( p->pUnlockConnection==db ){
+      assert( p->xUnlockNotify );
+      if( p->xUnlockNotify!=xUnlockNotify && nArg!=0 ){
+        xUnlockNotify(aArg, nArg);
+        nArg = 0;
+      }
+
+      sqlite3BeginBenignMalloc();
+      assert( aArg==aDyn || (aDyn==0 && aArg==aStatic) );
+      assert( nArg<=(int)ArraySize(aStatic) || aArg==aDyn );
+      if( (!aDyn && nArg==(int)ArraySize(aStatic))
+       || (aDyn && nArg==(int)(sqlite3MallocSize(aDyn)/sizeof(void*)))
+      ){
+        /* The aArg[] array needs to grow. */
+        void **pNew = (void **)sqlite3Malloc(nArg*sizeof(void *)*2);
+        if( pNew ){
+          memcpy(pNew, aArg, nArg*sizeof(void *));
+          sqlite3_free(aDyn);
+          aDyn = aArg = pNew;
+        }else{
+          /* This occurs when the array of context pointers that need to
+          ** be passed to the unlock-notify callback is larger than the
+          ** aStatic[] array allocated on the stack and the attempt to
+          ** allocate a larger array from the heap has failed.
+          **
+          ** This is a difficult situation to handle. Returning an error
+          ** code to the caller is insufficient, as even if an error code
+          ** is returned the transaction on connection db will still be
+          ** closed and the unlock-notify callbacks on blocked connections
+          ** will go unissued. This might cause the application to wait
+          ** indefinitely for an unlock-notify callback that will never
+          ** arrive.
+          **
+          ** Instead, invoke the unlock-notify callback with the context
+          ** array already accumulated. We can then clear the array and
+          ** begin accumulating any further context pointers without
+          ** requiring any dynamic allocation. This is sub-optimal because
+          ** it means that instead of one callback with a large array of
+          ** context pointers the application will receive two or more
+          ** callbacks with smaller arrays of context pointers, which will
+          ** reduce the applications ability to prioritize multiple
+          ** connections. But it is the best that can be done under the
+          ** circumstances.
+          */
+          xUnlockNotify(aArg, nArg);
+          nArg = 0;
+        }
+      }
+      sqlite3EndBenignMalloc();
+
+      aArg[nArg++] = p->pUnlockArg;
+      xUnlockNotify = p->xUnlockNotify;
+      p->pUnlockConnection = 0;
+      p->xUnlockNotify = 0;
+      p->pUnlockArg = 0;
+    }
+
+    /* Step 3. */
+    if( p->pBlockingConnection==0 && p->pUnlockConnection==0 ){
+      /* Remove connection p from the blocked connections list. */
+      *pp = p->pNextBlocked;
+      p->pNextBlocked = 0;
+    }else{
+      pp = &p->pNextBlocked;
+    }
+  }
+
+  if( nArg!=0 ){
+    xUnlockNotify(aArg, nArg);
+  }
+  sqlite3_free(aDyn);
+  leaveMutex();         /* Leave STATIC_MAIN mutex */
+}
+
+/*
+** This is called when the database connection passed as an argument is
+** being closed. The connection is removed from the blocked list.
+*/
+SQLITE_PRIVATE void sqlite3ConnectionClosed(sqlite3 *db){
+  sqlite3ConnectionUnlocked(db);
+  enterMutex();
+  removeFromBlockedList(db);
+  checkListProperties(db);
+  leaveMutex();
+}
+#endif
+
+/************** End of notify.c **********************************************/
+/************** Begin file fts3.c ********************************************/
+/*
+** 2006 Oct 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is an SQLite module implementing full-text search.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+
+/* The full-text index is stored in a series of b+tree (-like)
+** structures called segments which map terms to doclists.  The
+** structures are like b+trees in layout, but are constructed from the
+** bottom up in optimal fashion and are not updatable.  Since trees
+** are built from the bottom up, things will be described from the
+** bottom up.
+**
+**
+**** Varints ****
+** The basic unit of encoding is a variable-length integer called a
+** varint.  We encode variable-length integers in little-endian order
+** using seven bits * per byte as follows:
+**
+** KEY:
+**         A = 0xxxxxxx    7 bits of data and one flag bit
+**         B = 1xxxxxxx    7 bits of data and one flag bit
+**
+**  7 bits - A
+** 14 bits - BA
+** 21 bits - BBA
+** and so on.
+**
+** This is similar in concept to how sqlite encodes "varints" but
+** the encoding is not the same.  SQLite varints are big-endian
+** are are limited to 9 bytes in length whereas FTS3 varints are
+** little-endian and can be up to 10 bytes in length (in theory).
+**
+** Example encodings:
+**
+**     1:    0x01
+**   127:    0x7f
+**   128:    0x81 0x00
+**
+**
+**** Document lists ****
+** A doclist (document list) holds a docid-sorted list of hits for a
+** given term.  Doclists hold docids and associated token positions.
+** A docid is the unique integer identifier for a single document.
+** A position is the index of a word within the document.  The first
+** word of the document has a position of 0.
+**
+** FTS3 used to optionally store character offsets using a compile-time
+** option.  But that functionality is no longer supported.
+**
+** A doclist is stored like this:
+**
+** array {
+**   varint docid;          (delta from previous doclist)
+**   array {                (position list for column 0)
+**     varint position;     (2 more than the delta from previous position)
+**   }
+**   array {
+**     varint POS_COLUMN;   (marks start of position list for new column)
+**     varint column;       (index of new column)
+**     array {
+**       varint position;   (2 more than the delta from previous position)
+**     }
+**   }
+**   varint POS_END;        (marks end of positions for this document.
+** }
+**
+** Here, array { X } means zero or more occurrences of X, adjacent in
+** memory.  A "position" is an index of a token in the token stream
+** generated by the tokenizer. Note that POS_END and POS_COLUMN occur
+** in the same logical place as the position element, and act as sentinals
+** ending a position list array.  POS_END is 0.  POS_COLUMN is 1.
+** The positions numbers are not stored literally but rather as two more
+** than the difference from the prior position, or the just the position plus
+** 2 for the first position.  Example:
+**
+**   label:       A B C D E  F  G H   I  J K
+**   value:     123 5 9 1 1 14 35 0 234 72 0
+**
+** The 123 value is the first docid.  For column zero in this document
+** there are two matches at positions 3 and 10 (5-2 and 9-2+3).  The 1
+** at D signals the start of a new column; the 1 at E indicates that the
+** new column is column number 1.  There are two positions at 12 and 45
+** (14-2 and 35-2+12).  The 0 at H indicate the end-of-document.  The
+** 234 at I is the delta to next docid (357).  It has one position 70
+** (72-2) and then terminates with the 0 at K.
+**
+** A "position-list" is the list of positions for multiple columns for
+** a single docid.  A "column-list" is the set of positions for a single
+** column.  Hence, a position-list consists of one or more column-lists,
+** a document record consists of a docid followed by a position-list and
+** a doclist consists of one or more document records.
+**
+** A bare doclist omits the position information, becoming an
+** array of varint-encoded docids.
+**
+**** Segment leaf nodes ****
+** Segment leaf nodes store terms and doclists, ordered by term.  Leaf
+** nodes are written using LeafWriter, and read using LeafReader (to
+** iterate through a single leaf node's data) and LeavesReader (to
+** iterate through a segment's entire leaf layer).  Leaf nodes have
+** the format:
+**
+** varint iHeight;             (height from leaf level, always 0)
+** varint nTerm;               (length of first term)
+** char pTerm[nTerm];          (content of first term)
+** varint nDoclist;            (length of term's associated doclist)
+** char pDoclist[nDoclist];    (content of doclist)
+** array {
+**                             (further terms are delta-encoded)
+**   varint nPrefix;           (length of prefix shared with previous term)
+**   varint nSuffix;           (length of unshared suffix)
+**   char pTermSuffix[nSuffix];(unshared suffix of next term)
+**   varint nDoclist;          (length of term's associated doclist)
+**   char pDoclist[nDoclist];  (content of doclist)
+** }
+**
+** Here, array { X } means zero or more occurrences of X, adjacent in
+** memory.
+**
+** Leaf nodes are broken into blocks which are stored contiguously in
+** the %_segments table in sorted order.  This means that when the end
+** of a node is reached, the next term is in the node with the next
+** greater node id.
+**
+** New data is spilled to a new leaf node when the current node
+** exceeds LEAF_MAX bytes (default 2048).  New data which itself is
+** larger than STANDALONE_MIN (default 1024) is placed in a standalone
+** node (a leaf node with a single term and doclist).  The goal of
+** these settings is to pack together groups of small doclists while
+** making it efficient to directly access large doclists.  The
+** assumption is that large doclists represent terms which are more
+** likely to be query targets.
+**
+** TODO(shess) It may be useful for blocking decisions to be more
+** dynamic.  For instance, it may make more sense to have a 2.5k leaf
+** node rather than splitting into 2k and .5k nodes.  My intuition is
+** that this might extend through 2x or 4x the pagesize.
+**
+**
+**** Segment interior nodes ****
+** Segment interior nodes store blockids for subtree nodes and terms
+** to describe what data is stored by the each subtree.  Interior
+** nodes are written using InteriorWriter, and read using
+** InteriorReader.  InteriorWriters are created as needed when
+** SegmentWriter creates new leaf nodes, or when an interior node
+** itself grows too big and must be split.  The format of interior
+** nodes:
+**
+** varint iHeight;           (height from leaf level, always >0)
+** varint iBlockid;          (block id of node's leftmost subtree)
+** optional {
+**   varint nTerm;           (length of first term)
+**   char pTerm[nTerm];      (content of first term)
+**   array {
+**                                (further terms are delta-encoded)
+**     varint nPrefix;            (length of shared prefix with previous term)
+**     varint nSuffix;            (length of unshared suffix)
+**     char pTermSuffix[nSuffix]; (unshared suffix of next term)
+**   }
+** }
+**
+** Here, optional { X } means an optional element, while array { X }
+** means zero or more occurrences of X, adjacent in memory.
+**
+** An interior node encodes n terms separating n+1 subtrees.  The
+** subtree blocks are contiguous, so only the first subtree's blockid
+** is encoded.  The subtree at iBlockid will contain all terms less
+** than the first term encoded (or all terms if no term is encoded).
+** Otherwise, for terms greater than or equal to pTerm[i] but less
+** than pTerm[i+1], the subtree for that term will be rooted at
+** iBlockid+i.  Interior nodes only store enough term data to
+** distinguish adjacent children (if the rightmost term of the left
+** child is "something", and the leftmost term of the right child is
+** "wicked", only "w" is stored).
+**
+** New data is spilled to a new interior node at the same height when
+** the current node exceeds INTERIOR_MAX bytes (default 2048).
+** INTERIOR_MIN_TERMS (default 7) keeps large terms from monopolizing
+** interior nodes and making the tree too skinny.  The interior nodes
+** at a given height are naturally tracked by interior nodes at
+** height+1, and so on.
+**
+**
+**** Segment directory ****
+** The segment directory in table %_segdir stores meta-information for
+** merging and deleting segments, and also the root node of the
+** segment's tree.
+**
+** The root node is the top node of the segment's tree after encoding
+** the entire segment, restricted to ROOT_MAX bytes (default 1024).
+** This could be either a leaf node or an interior node.  If the top
+** node requires more than ROOT_MAX bytes, it is flushed to %_segments
+** and a new root interior node is generated (which should always fit
+** within ROOT_MAX because it only needs space for 2 varints, the
+** height and the blockid of the previous root).
+**
+** The meta-information in the segment directory is:
+**   level               - segment level (see below)
+**   idx                 - index within level
+**                       - (level,idx uniquely identify a segment)
+**   start_block         - first leaf node
+**   leaves_end_block    - last leaf node
+**   end_block           - last block (including interior nodes)
+**   root                - contents of root node
+**
+** If the root node is a leaf node, then start_block,
+** leaves_end_block, and end_block are all 0.
+**
+**
+**** Segment merging ****
+** To amortize update costs, segments are grouped into levels and
+** merged in batches.  Each increase in level represents exponentially
+** more documents.
+**
+** New documents (actually, document updates) are tokenized and
+** written individually (using LeafWriter) to a level 0 segment, with
+** incrementing idx.  When idx reaches MERGE_COUNT (default 16), all
+** level 0 segments are merged into a single level 1 segment.  Level 1
+** is populated like level 0, and eventually MERGE_COUNT level 1
+** segments are merged to a single level 2 segment (representing
+** MERGE_COUNT^2 updates), and so on.
+**
+** A segment merge traverses all segments at a given level in
+** parallel, performing a straightforward sorted merge.  Since segment
+** leaf nodes are written in to the %_segments table in order, this
+** merge traverses the underlying sqlite disk structures efficiently.
+** After the merge, all segment blocks from the merged level are
+** deleted.
+**
+** MERGE_COUNT controls how often we merge segments.  16 seems to be
+** somewhat of a sweet spot for insertion performance.  32 and 64 show
+** very similar performance numbers to 16 on insertion, though they're
+** a tiny bit slower (perhaps due to more overhead in merge-time
+** sorting).  8 is about 20% slower than 16, 4 about 50% slower than
+** 16, 2 about 66% slower than 16.
+**
+** At query time, high MERGE_COUNT increases the number of segments
+** which need to be scanned and merged.  For instance, with 100k docs
+** inserted:
+**
+**    MERGE_COUNT   segments
+**       16           25
+**        8           12
+**        4           10
+**        2            6
+**
+** This appears to have only a moderate impact on queries for very
+** frequent terms (which are somewhat dominated by segment merge
+** costs), and infrequent and non-existent terms still seem to be fast
+** even with many segments.
+**
+** TODO(shess) That said, it would be nice to have a better query-side
+** argument for MERGE_COUNT of 16.  Also, it is possible/likely that
+** optimizations to things like doclist merging will swing the sweet
+** spot around.
+**
+**
+**
+**** Handling of deletions and updates ****
+** Since we're using a segmented structure, with no docid-oriented
+** index into the term index, we clearly cannot simply update the term
+** index when a document is deleted or updated.  For deletions, we
+** write an empty doclist (varint(docid) varint(POS_END)), for updates
+** we simply write the new doclist.  Segment merges overwrite older
+** data for a particular docid with newer data, so deletes or updates
+** will eventually overtake the earlier data and knock it out.  The
+** query logic likewise merges doclists so that newer data knocks out
+** older data.
+*/
+
+/************** Include fts3Int.h in the middle of fts3.c ********************/
+/************** Begin file fts3Int.h *****************************************/
+/*
+** 2009 Nov 12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+#ifndef _FTSINT_H
+#define _FTSINT_H
+
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+
+/* FTS3/FTS4 require virtual tables */
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+# undef SQLITE_ENABLE_FTS3
+# undef SQLITE_ENABLE_FTS4
+#endif
+
+/*
+** FTS4 is really an extension for FTS3.  It is enabled using the
+** SQLITE_ENABLE_FTS3 macro.  But to avoid confusion we also all
+** the SQLITE_ENABLE_FTS4 macro to serve as an alisse for SQLITE_ENABLE_FTS3.
+*/
+#if defined(SQLITE_ENABLE_FTS4) && !defined(SQLITE_ENABLE_FTS3)
+# define SQLITE_ENABLE_FTS3
+#endif
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* If not building as part of the core, include sqlite3ext.h. */
+#ifndef SQLITE_CORE
+/* # include "sqlite3ext.h" */
+SQLITE_EXTENSION_INIT3
+#endif
+
+/* #include "sqlite3.h" */
+/************** Include fts3_tokenizer.h in the middle of fts3Int.h **********/
+/************** Begin file fts3_tokenizer.h **********************************/
+/*
+** 2006 July 10
+**
+** The author disclaims copyright to this source code.
+**
+*************************************************************************
+** Defines the interface to tokenizers used by fulltext-search.  There
+** are three basic components:
+**
+** sqlite3_tokenizer_module is a singleton defining the tokenizer
+** interface functions.  This is essentially the class structure for
+** tokenizers.
+**
+** sqlite3_tokenizer is used to define a particular tokenizer, perhaps
+** including customization information defined at creation time.
+**
+** sqlite3_tokenizer_cursor is generated by a tokenizer to generate
+** tokens from a particular input.
+*/
+#ifndef _FTS3_TOKENIZER_H_
+#define _FTS3_TOKENIZER_H_
+
+/* TODO(shess) Only used for SQLITE_OK and SQLITE_DONE at this time.
+** If tokenizers are to be allowed to call sqlite3_*() functions, then
+** we will need a way to register the API consistently.
+*/
+/* #include "sqlite3.h" */
+
+/*
+** Structures used by the tokenizer interface. When a new tokenizer
+** implementation is registered, the caller provides a pointer to
+** an sqlite3_tokenizer_module containing pointers to the callback
+** functions that make up an implementation.
+**
+** When an fts3 table is created, it passes any arguments passed to
+** the tokenizer clause of the CREATE VIRTUAL TABLE statement to the
+** sqlite3_tokenizer_module.xCreate() function of the requested tokenizer
+** implementation. The xCreate() function in turn returns an
+** sqlite3_tokenizer structure representing the specific tokenizer to
+** be used for the fts3 table (customized by the tokenizer clause arguments).
+**
+** To tokenize an input buffer, the sqlite3_tokenizer_module.xOpen()
+** method is called. It returns an sqlite3_tokenizer_cursor object
+** that may be used to tokenize a specific input buffer based on
+** the tokenization rules supplied by a specific sqlite3_tokenizer
+** object.
+*/
+typedef struct sqlite3_tokenizer_module sqlite3_tokenizer_module;
+typedef struct sqlite3_tokenizer sqlite3_tokenizer;
+typedef struct sqlite3_tokenizer_cursor sqlite3_tokenizer_cursor;
+
+struct sqlite3_tokenizer_module {
+
+  /*
+  ** Structure version. Should always be set to 0 or 1.
+  */
+  int iVersion;
+
+  /*
+  ** Create a new tokenizer. The values in the argv[] array are the
+  ** arguments passed to the "tokenizer" clause of the CREATE VIRTUAL
+  ** TABLE statement that created the fts3 table. For example, if
+  ** the following SQL is executed:
+  **
+  **   CREATE .. USING fts3( ... , tokenizer <tokenizer-name> arg1 arg2)
+  **
+  ** then argc is set to 2, and the argv[] array contains pointers
+  ** to the strings "arg1" and "arg2".
+  **
+  ** This method should return either SQLITE_OK (0), or an SQLite error
+  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
+  ** to point at the newly created tokenizer structure. The generic
+  ** sqlite3_tokenizer.pModule variable should not be initialized by
+  ** this callback. The caller will do so.
+  */
+  int (*xCreate)(
+    int argc,                           /* Size of argv array */
+    const char *const*argv,             /* Tokenizer argument strings */
+    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
+  );
+
+  /*
+  ** Destroy an existing tokenizer. The fts3 module calls this method
+  ** exactly once for each successful call to xCreate().
+  */
+  int (*xDestroy)(sqlite3_tokenizer *pTokenizer);
+
+  /*
+  ** Create a tokenizer cursor to tokenize an input buffer. The caller
+  ** is responsible for ensuring that the input buffer remains valid
+  ** until the cursor is closed (using the xClose() method).
+  */
+  int (*xOpen)(
+    sqlite3_tokenizer *pTokenizer,       /* Tokenizer object */
+    const char *pInput, int nBytes,      /* Input buffer */
+    sqlite3_tokenizer_cursor **ppCursor  /* OUT: Created tokenizer cursor */
+  );
+
+  /*
+  ** Destroy an existing tokenizer cursor. The fts3 module calls this
+  ** method exactly once for each successful call to xOpen().
+  */
+  int (*xClose)(sqlite3_tokenizer_cursor *pCursor);
+
+  /*
+  ** Retrieve the next token from the tokenizer cursor pCursor. This
+  ** method should either return SQLITE_OK and set the values of the
+  ** "OUT" variables identified below, or SQLITE_DONE to indicate that
+  ** the end of the buffer has been reached, or an SQLite error code.
+  **
+  ** *ppToken should be set to point at a buffer containing the
+  ** normalized version of the token (i.e. after any case-folding and/or
+  ** stemming has been performed). *pnBytes should be set to the length
+  ** of this buffer in bytes. The input text that generated the token is
+  ** identified by the byte offsets returned in *piStartOffset and
+  ** *piEndOffset. *piStartOffset should be set to the index of the first
+  ** byte of the token in the input buffer. *piEndOffset should be set
+  ** to the index of the first byte just past the end of the token in
+  ** the input buffer.
+  **
+  ** The buffer *ppToken is set to point at is managed by the tokenizer
+  ** implementation. It is only required to be valid until the next call
+  ** to xNext() or xClose().
+  */
+  /* TODO(shess) current implementation requires pInput to be
+  ** nul-terminated.  This should either be fixed, or pInput/nBytes
+  ** should be converted to zInput.
+  */
+  int (*xNext)(
+    sqlite3_tokenizer_cursor *pCursor,   /* Tokenizer cursor */
+    const char **ppToken, int *pnBytes,  /* OUT: Normalized text for token */
+    int *piStartOffset,  /* OUT: Byte offset of token in input buffer */
+    int *piEndOffset,    /* OUT: Byte offset of end of token in input buffer */
+    int *piPosition      /* OUT: Number of tokens returned before this one */
+  );
+
+  /***********************************************************************
+  ** Methods below this point are only available if iVersion>=1.
+  */
+
+  /*
+  ** Configure the language id of a tokenizer cursor.
+  */
+  int (*xLanguageid)(sqlite3_tokenizer_cursor *pCsr, int iLangid);
+};
+
+struct sqlite3_tokenizer {
+  const sqlite3_tokenizer_module *pModule;  /* The module for this tokenizer */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+struct sqlite3_tokenizer_cursor {
+  sqlite3_tokenizer *pTokenizer;       /* Tokenizer for this cursor. */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+int fts3_global_term_cnt(int iTerm, int iCol);
+int fts3_term_cnt(int iTerm, int iCol);
+
+
+#endif /* _FTS3_TOKENIZER_H_ */
+
+/************** End of fts3_tokenizer.h **************************************/
+/************** Continuing where we left off in fts3Int.h ********************/
+/************** Include fts3_hash.h in the middle of fts3Int.h ***************/
+/************** Begin file fts3_hash.h ***************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the header file for the generic hash-table implementation
+** used in SQLite.  We've modified it slightly to serve as a standalone
+** hash table implementation for the full-text indexing module.
+**
+*/
+#ifndef _FTS3_HASH_H_
+#define _FTS3_HASH_H_
+
+/* Forward declarations of structures. */
+typedef struct Fts3Hash Fts3Hash;
+typedef struct Fts3HashElem Fts3HashElem;
+
+/* A complete hash table is an instance of the following structure.
+** The internals of this structure are intended to be opaque -- client
+** code should not attempt to access or modify the fields of this structure
+** directly.  Change this structure only by using the routines below.
+** However, many of the "procedures" and "functions" for modifying and
+** accessing this structure are really macros, so we can't really make
+** this structure opaque.
+*/
+struct Fts3Hash {
+  char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
+  char copyKey;           /* True if copy of key made on insert */
+  int count;              /* Number of entries in this table */
+  Fts3HashElem *first;    /* The first element of the array */
+  int htsize;             /* Number of buckets in the hash table */
+  struct _fts3ht {        /* the hash table */
+    int count;               /* Number of entries with this hash */
+    Fts3HashElem *chain;     /* Pointer to first entry with this hash */
+  } *ht;
+};
+
+/* Each element in the hash table is an instance of the following
+** structure.  All elements are stored on a single doubly-linked list.
+**
+** Again, this structure is intended to be opaque, but it can't really
+** be opaque because it is used by macros.
+*/
+struct Fts3HashElem {
+  Fts3HashElem *next, *prev; /* Next and previous elements in the table */
+  void *data;                /* Data associated with this element */
+  void *pKey; int nKey;      /* Key associated with this element */
+};
+
+/*
+** There are 2 different modes of operation for a hash table:
+**
+**   FTS3_HASH_STRING        pKey points to a string that is nKey bytes long
+**                           (including the null-terminator, if any).  Case
+**                           is respected in comparisons.
+**
+**   FTS3_HASH_BINARY        pKey points to binary data nKey bytes long.
+**                           memcmp() is used to compare keys.
+**
+** A copy of the key is made if the copyKey parameter to fts3HashInit is 1.
+*/
+#define FTS3_HASH_STRING    1
+#define FTS3_HASH_BINARY    2
+
+/*
+** Access routines.  To delete, insert a NULL pointer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashInit(Fts3Hash *pNew, char keyClass, char copyKey);
+SQLITE_PRIVATE void *sqlite3Fts3HashInsert(Fts3Hash*, const void *pKey, int nKey, void *pData);
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const Fts3Hash*, const void *pKey, int nKey);
+SQLITE_PRIVATE void sqlite3Fts3HashClear(Fts3Hash*);
+SQLITE_PRIVATE Fts3HashElem *sqlite3Fts3HashFindElem(const Fts3Hash *, const void *, int);
+
+/*
+** Shorthand for the functions above
+*/
+#define fts3HashInit     sqlite3Fts3HashInit
+#define fts3HashInsert   sqlite3Fts3HashInsert
+#define fts3HashFind     sqlite3Fts3HashFind
+#define fts3HashClear    sqlite3Fts3HashClear
+#define fts3HashFindElem sqlite3Fts3HashFindElem
+
+/*
+** Macros for looping over all elements of a hash table.  The idiom is
+** like this:
+**
+**   Fts3Hash h;
+**   Fts3HashElem *p;
+**   ...
+**   for(p=fts3HashFirst(&h); p; p=fts3HashNext(p)){
+**     SomeStructure *pData = fts3HashData(p);
+**     // do something with pData
+**   }
+*/
+#define fts3HashFirst(H)  ((H)->first)
+#define fts3HashNext(E)   ((E)->next)
+#define fts3HashData(E)   ((E)->data)
+#define fts3HashKey(E)    ((E)->pKey)
+#define fts3HashKeysize(E) ((E)->nKey)
+
+/*
+** Number of entries in a hash table
+*/
+#define fts3HashCount(H)  ((H)->count)
+
+#endif /* _FTS3_HASH_H_ */
+
+/************** End of fts3_hash.h *******************************************/
+/************** Continuing where we left off in fts3Int.h ********************/
+
+/*
+** This constant determines the maximum depth of an FTS expression tree
+** that the library will create and use. FTS uses recursion to perform
+** various operations on the query tree, so the disadvantage of a large
+** limit is that it may allow very large queries to use large amounts
+** of stack space (perhaps causing a stack overflow).
+*/
+#ifndef SQLITE_FTS3_MAX_EXPR_DEPTH
+# define SQLITE_FTS3_MAX_EXPR_DEPTH 12
+#endif
+
+
+/*
+** This constant controls how often segments are merged. Once there are
+** FTS3_MERGE_COUNT segments of level N, they are merged into a single
+** segment of level N+1.
+*/
+#define FTS3_MERGE_COUNT 16
+
+/*
+** This is the maximum amount of data (in bytes) to store in the
+** Fts3Table.pendingTerms hash table. Normally, the hash table is
+** populated as documents are inserted/updated/deleted in a transaction
+** and used to create a new segment when the transaction is committed.
+** However if this limit is reached midway through a transaction, a new
+** segment is created and the hash table cleared immediately.
+*/
+#define FTS3_MAX_PENDING_DATA (1*1024*1024)
+
+/*
+** Macro to return the number of elements in an array. SQLite has a
+** similar macro called ArraySize(). Use a different name to avoid
+** a collision when building an amalgamation with built-in FTS3.
+*/
+#define SizeofArray(X) ((int)(sizeof(X)/sizeof(X[0])))
+
+
+#ifndef MIN
+# define MIN(x,y) ((x)<(y)?(x):(y))
+#endif
+#ifndef MAX
+# define MAX(x,y) ((x)>(y)?(x):(y))
+#endif
+
+/*
+** Maximum length of a varint encoded integer. The varint format is different
+** from that used by SQLite, so the maximum length is 10, not 9.
+*/
+#define FTS3_VARINT_MAX 10
+
+#define FTS3_BUFFER_PADDING 8
+
+/*
+** FTS4 virtual tables may maintain multiple indexes - one index of all terms
+** in the document set and zero or more prefix indexes. All indexes are stored
+** as one or more b+-trees in the %_segments and %_segdir tables.
+**
+** It is possible to determine which index a b+-tree belongs to based on the
+** value stored in the "%_segdir.level" column. Given this value L, the index
+** that the b+-tree belongs to is (L<<10). In other words, all b+-trees with
+** level values between 0 and 1023 (inclusive) belong to index 0, all levels
+** between 1024 and 2047 to index 1, and so on.
+**
+** It is considered impossible for an index to use more than 1024 levels. In
+** theory though this may happen, but only after at least
+** (FTS3_MERGE_COUNT^1024) separate flushes of the pending-terms tables.
+*/
+#define FTS3_SEGDIR_MAXLEVEL      1024
+#define FTS3_SEGDIR_MAXLEVEL_STR "1024"
+
+/*
+** The testcase() macro is only used by the amalgamation.  If undefined,
+** make it a no-op.
+*/
+#ifndef testcase
+# define testcase(X)
+#endif
+
+/*
+** Terminator values for position-lists and column-lists.
+*/
+#define POS_COLUMN  (1)     /* Column-list terminator */
+#define POS_END     (0)     /* Position-list terminator */
+
+/*
+** The assert_fts3_nc() macro is similar to the assert() macro, except that it
+** is used for assert() conditions that are true only if it can be
+** guranteed that the database is not corrupt.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_API extern int sqlite3_fts3_may_be_corrupt;
+# define assert_fts3_nc(x) assert(sqlite3_fts3_may_be_corrupt || (x))
+#else
+# define assert_fts3_nc(x) assert(x)
+#endif
+
+/*
+** This section provides definitions to allow the
+** FTS3 extension to be compiled outside of the
+** amalgamation.
+*/
+#ifndef SQLITE_AMALGAMATION
+/*
+** Macros indicating that conditional expressions are always true or
+** false.
+*/
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
+# define SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS 1
+#endif
+#if defined(SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS)
+# define ALWAYS(X)      (1)
+# define NEVER(X)       (0)
+#elif !defined(NDEBUG)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
+#else
+# define ALWAYS(X)      (X)
+# define NEVER(X)       (X)
+#endif
+
+/*
+** Internal types used by SQLite.
+*/
+typedef unsigned char u8;         /* 1-byte (or larger) unsigned integer */
+typedef short int i16;            /* 2-byte (or larger) signed integer */
+typedef unsigned int u32;         /* 4-byte unsigned integer */
+typedef sqlite3_uint64 u64;       /* 8-byte unsigned integer */
+typedef sqlite3_int64 i64;        /* 8-byte signed integer */
+
+/*
+** Macro used to suppress compiler warnings for unused parameters.
+*/
+#define UNUSED_PARAMETER(x) (void)(x)
+
+/*
+** Activate assert() only if SQLITE_TEST is enabled.
+*/
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+
+/*
+** The TESTONLY macro is used to enclose variable declarations or
+** other bits of code that are needed to support the arguments
+** within testcase() and assert() macros.
+*/
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+# define TESTONLY(X)  X
+#else
+# define TESTONLY(X)
+#endif
+
+#define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
+#define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
+
+#define deliberate_fall_through
+
+#endif /* SQLITE_AMALGAMATION */
+
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3Fts3Corrupt(void);
+# define FTS_CORRUPT_VTAB sqlite3Fts3Corrupt()
+#else
+# define FTS_CORRUPT_VTAB SQLITE_CORRUPT_VTAB
+#endif
+
+typedef struct Fts3Table Fts3Table;
+typedef struct Fts3Cursor Fts3Cursor;
+typedef struct Fts3Expr Fts3Expr;
+typedef struct Fts3Phrase Fts3Phrase;
+typedef struct Fts3PhraseToken Fts3PhraseToken;
+
+typedef struct Fts3Doclist Fts3Doclist;
+typedef struct Fts3SegFilter Fts3SegFilter;
+typedef struct Fts3DeferredToken Fts3DeferredToken;
+typedef struct Fts3SegReader Fts3SegReader;
+typedef struct Fts3MultiSegReader Fts3MultiSegReader;
+
+typedef struct MatchinfoBuffer MatchinfoBuffer;
+
+/*
+** A connection to a fulltext index is an instance of the following
+** structure. The xCreate and xConnect methods create an instance
+** of this structure and xDestroy and xDisconnect free that instance.
+** All other methods receive a pointer to the structure as one of their
+** arguments.
+*/
+struct Fts3Table {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  sqlite3 *db;                    /* The database connection */
+  const char *zDb;                /* logical database name */
+  const char *zName;              /* virtual table name */
+  int nColumn;                    /* number of named columns in virtual table */
+  char **azColumn;                /* column names.  malloced */
+  u8 *abNotindexed;               /* True for 'notindexed' columns */
+  sqlite3_tokenizer *pTokenizer;  /* tokenizer for inserts and queries */
+  char *zContentTbl;              /* content=xxx option, or NULL */
+  char *zLanguageid;              /* languageid=xxx option, or NULL */
+  int nAutoincrmerge;             /* Value configured by 'automerge' */
+  u32 nLeafAdd;                   /* Number of leaf blocks added this trans */
+  int bLock;                      /* Used to prevent recursive content= tbls */
+
+  /* Precompiled statements used by the implementation. Each of these
+  ** statements is run and reset within a single virtual table API call.
+  */
+  sqlite3_stmt *aStmt[40];
+  sqlite3_stmt *pSeekStmt;        /* Cache for fts3CursorSeekStmt() */
+
+  char *zReadExprlist;
+  char *zWriteExprlist;
+
+  int nNodeSize;                  /* Soft limit for node size */
+  u8 bFts4;                       /* True for FTS4, false for FTS3 */
+  u8 bHasStat;                    /* True if %_stat table exists (2==unknown) */
+  u8 bHasDocsize;                 /* True if %_docsize table exists */
+  u8 bDescIdx;                    /* True if doclists are in reverse order */
+  u8 bIgnoreSavepoint;            /* True to ignore xSavepoint invocations */
+  int nPgsz;                      /* Page size for host database */
+  char *zSegmentsTbl;             /* Name of %_segments table */
+  sqlite3_blob *pSegments;        /* Blob handle open on %_segments table */
+  int iSavepoint;
+
+  /*
+  ** The following array of hash tables is used to buffer pending index
+  ** updates during transactions. All pending updates buffered at any one
+  ** time must share a common language-id (see the FTS4 langid= feature).
+  ** The current language id is stored in variable iPrevLangid.
+  **
+  ** A single FTS4 table may have multiple full-text indexes. For each index
+  ** there is an entry in the aIndex[] array. Index 0 is an index of all the
+  ** terms that appear in the document set. Each subsequent index in aIndex[]
+  ** is an index of prefixes of a specific length.
+  **
+  ** Variable nPendingData contains an estimate the memory consumed by the
+  ** pending data structures, including hash table overhead, but not including
+  ** malloc overhead.  When nPendingData exceeds nMaxPendingData, all hash
+  ** tables are flushed to disk. Variable iPrevDocid is the docid of the most
+  ** recently inserted record.
+  */
+  int nIndex;                     /* Size of aIndex[] */
+  struct Fts3Index {
+    int nPrefix;                  /* Prefix length (0 for main terms index) */
+    Fts3Hash hPending;            /* Pending terms table for this index */
+  } *aIndex;
+  int nMaxPendingData;            /* Max pending data before flush to disk */
+  int nPendingData;               /* Current bytes of pending data */
+  sqlite_int64 iPrevDocid;        /* Docid of most recently inserted document */
+  int iPrevLangid;                /* Langid of recently inserted document */
+  int bPrevDelete;                /* True if last operation was a delete */
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
+  /* State variables used for validating that the transaction control
+  ** methods of the virtual table are called at appropriate times.  These
+  ** values do not contribute to FTS functionality; they are used for
+  ** verifying the operation of the SQLite core.
+  */
+  int inTransaction;     /* True after xBegin but before xCommit/xRollback */
+  int mxSavepoint;       /* Largest valid xSavepoint integer */
+#endif
+
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  /* True to disable the incremental doclist optimization. This is controled
+  ** by special insert command 'test-no-incr-doclist'.  */
+  int bNoIncrDoclist;
+
+  /* Number of segments in a level */
+  int nMergeCount;
+#endif
+};
+
+/* Macro to find the number of segments to merge */
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+# define MergeCount(P) ((P)->nMergeCount)
+#else
+# define MergeCount(P) FTS3_MERGE_COUNT
+#endif
+
+/*
+** When the core wants to read from the virtual table, it creates a
+** virtual table cursor (an instance of the following structure) using
+** the xOpen method. Cursors are destroyed using the xClose method.
+*/
+struct Fts3Cursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  i16 eSearch;                    /* Search strategy (see below) */
+  u8 isEof;                       /* True if at End Of Results */
+  u8 isRequireSeek;               /* True if must seek pStmt to %_content row */
+  u8 bSeekStmt;                   /* True if pStmt is a seek */
+  sqlite3_stmt *pStmt;            /* Prepared statement in use by the cursor */
+  Fts3Expr *pExpr;                /* Parsed MATCH query string */
+  int iLangid;                    /* Language being queried for */
+  int nPhrase;                    /* Number of matchable phrases in query */
+  Fts3DeferredToken *pDeferred;   /* Deferred search tokens, if any */
+  sqlite3_int64 iPrevId;          /* Previous id read from aDoclist */
+  char *pNextId;                  /* Pointer into the body of aDoclist */
+  char *aDoclist;                 /* List of docids for full-text queries */
+  int nDoclist;                   /* Size of buffer at aDoclist */
+  u8 bDesc;                       /* True to sort in descending order */
+  int eEvalmode;                  /* An FTS3_EVAL_XX constant */
+  int nRowAvg;                    /* Average size of database rows, in pages */
+  sqlite3_int64 nDoc;             /* Documents in table */
+  i64 iMinDocid;                  /* Minimum docid to return */
+  i64 iMaxDocid;                  /* Maximum docid to return */
+  int isMatchinfoNeeded;          /* True when aMatchinfo[] needs filling in */
+  MatchinfoBuffer *pMIBuffer;     /* Buffer for matchinfo data */
+};
+
+#define FTS3_EVAL_FILTER    0
+#define FTS3_EVAL_NEXT      1
+#define FTS3_EVAL_MATCHINFO 2
+
+/*
+** The Fts3Cursor.eSearch member is always set to one of the following.
+** Actualy, Fts3Cursor.eSearch can be greater than or equal to
+** FTS3_FULLTEXT_SEARCH.  If so, then Fts3Cursor.eSearch - 2 is the index
+** of the column to be searched.  For example, in
+**
+**     CREATE VIRTUAL TABLE ex1 USING fts3(a,b,c,d);
+**     SELECT docid FROM ex1 WHERE b MATCH 'one two three';
+**
+** Because the LHS of the MATCH operator is 2nd column "b",
+** Fts3Cursor.eSearch will be set to FTS3_FULLTEXT_SEARCH+1.  (+0 for a,
+** +1 for b, +2 for c, +3 for d.)  If the LHS of MATCH were "ex1"
+** indicating that all columns should be searched,
+** then eSearch would be set to FTS3_FULLTEXT_SEARCH+4.
+*/
+#define FTS3_FULLSCAN_SEARCH 0    /* Linear scan of %_content table */
+#define FTS3_DOCID_SEARCH    1    /* Lookup by rowid on %_content table */
+#define FTS3_FULLTEXT_SEARCH 2    /* Full-text index search */
+
+/*
+** The lower 16-bits of the sqlite3_index_info.idxNum value set by
+** the xBestIndex() method contains the Fts3Cursor.eSearch value described
+** above. The upper 16-bits contain a combination of the following
+** bits, used to describe extra constraints on full-text searches.
+*/
+#define FTS3_HAVE_LANGID    0x00010000      /* languageid=? */
+#define FTS3_HAVE_DOCID_GE  0x00020000      /* docid>=? */
+#define FTS3_HAVE_DOCID_LE  0x00040000      /* docid<=? */
+
+struct Fts3Doclist {
+  char *aAll;                    /* Array containing doclist (or NULL) */
+  int nAll;                      /* Size of a[] in bytes */
+  char *pNextDocid;              /* Pointer to next docid */
+
+  sqlite3_int64 iDocid;          /* Current docid (if pList!=0) */
+  int bFreeList;                 /* True if pList should be sqlite3_free()d */
+  char *pList;                   /* Pointer to position list following iDocid */
+  int nList;                     /* Length of position list */
+};
+
+/*
+** A "phrase" is a sequence of one or more tokens that must match in
+** sequence.  A single token is the base case and the most common case.
+** For a sequence of tokens contained in double-quotes (i.e. "one two three")
+** nToken will be the number of tokens in the string.
+*/
+struct Fts3PhraseToken {
+  char *z;                        /* Text of the token */
+  int n;                          /* Number of bytes in buffer z */
+  int isPrefix;                   /* True if token ends with a "*" character */
+  int bFirst;                     /* True if token must appear at position 0 */
+
+  /* Variables above this point are populated when the expression is
+  ** parsed (by code in fts3_expr.c). Below this point the variables are
+  ** used when evaluating the expression. */
+  Fts3DeferredToken *pDeferred;   /* Deferred token object for this token */
+  Fts3MultiSegReader *pSegcsr;    /* Segment-reader for this token */
+};
+
+struct Fts3Phrase {
+  /* Cache of doclist for this phrase. */
+  Fts3Doclist doclist;
+  int bIncr;                 /* True if doclist is loaded incrementally */
+  int iDoclistToken;
+
+  /* Used by sqlite3Fts3EvalPhrasePoslist() if this is a descendent of an
+  ** OR condition.  */
+  char *pOrPoslist;
+  i64 iOrDocid;
+
+  /* Variables below this point are populated by fts3_expr.c when parsing
+  ** a MATCH expression. Everything above is part of the evaluation phase.
+  */
+  int nToken;                /* Number of tokens in the phrase */
+  int iColumn;               /* Index of column this phrase must match */
+  Fts3PhraseToken aToken[1]; /* One entry for each token in the phrase */
+};
+
+/*
+** A tree of these objects forms the RHS of a MATCH operator.
+**
+** If Fts3Expr.eType is FTSQUERY_PHRASE and isLoaded is true, then aDoclist
+** points to a malloced buffer, size nDoclist bytes, containing the results
+** of this phrase query in FTS3 doclist format. As usual, the initial
+** "Length" field found in doclists stored on disk is omitted from this
+** buffer.
+**
+** Variable aMI is used only for FTSQUERY_NEAR nodes to store the global
+** matchinfo data. If it is not NULL, it points to an array of size nCol*3,
+** where nCol is the number of columns in the queried FTS table. The array
+** is populated as follows:
+**
+**   aMI[iCol*3 + 0] = Undefined
+**   aMI[iCol*3 + 1] = Number of occurrences
+**   aMI[iCol*3 + 2] = Number of rows containing at least one instance
+**
+** The aMI array is allocated using sqlite3_malloc(). It should be freed
+** when the expression node is.
+*/
+struct Fts3Expr {
+  int eType;                 /* One of the FTSQUERY_XXX values defined below */
+  int nNear;                 /* Valid if eType==FTSQUERY_NEAR */
+  Fts3Expr *pParent;         /* pParent->pLeft==this or pParent->pRight==this */
+  Fts3Expr *pLeft;           /* Left operand */
+  Fts3Expr *pRight;          /* Right operand */
+  Fts3Phrase *pPhrase;       /* Valid if eType==FTSQUERY_PHRASE */
+
+  /* The following are used by the fts3_eval.c module. */
+  sqlite3_int64 iDocid;      /* Current docid */
+  u8 bEof;                   /* True this expression is at EOF already */
+  u8 bStart;                 /* True if iDocid is valid */
+  u8 bDeferred;              /* True if this expression is entirely deferred */
+
+  /* The following are used by the fts3_snippet.c module. */
+  int iPhrase;               /* Index of this phrase in matchinfo() results */
+  u32 *aMI;                  /* See above */
+};
+
+/*
+** Candidate values for Fts3Query.eType. Note that the order of the first
+** four values is in order of precedence when parsing expressions. For
+** example, the following:
+**
+**   "a OR b AND c NOT d NEAR e"
+**
+** is equivalent to:
+**
+**   "a OR (b AND (c NOT (d NEAR e)))"
+*/
+#define FTSQUERY_NEAR   1
+#define FTSQUERY_NOT    2
+#define FTSQUERY_AND    3
+#define FTSQUERY_OR     4
+#define FTSQUERY_PHRASE 5
+
+
+/* fts3_write.c */
+SQLITE_PRIVATE int sqlite3Fts3UpdateMethod(sqlite3_vtab*,int,sqlite3_value**,sqlite3_int64*);
+SQLITE_PRIVATE int sqlite3Fts3PendingTermsFlush(Fts3Table *);
+SQLITE_PRIVATE void sqlite3Fts3PendingTermsClear(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3Optimize(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3SegReaderNew(int, int, sqlite3_int64,
+  sqlite3_int64, sqlite3_int64, const char *, int, Fts3SegReader**);
+SQLITE_PRIVATE int sqlite3Fts3SegReaderPending(
+  Fts3Table*,int,const char*,int,int,Fts3SegReader**);
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFree(Fts3SegReader *);
+SQLITE_PRIVATE int sqlite3Fts3AllSegdirs(Fts3Table*, int, int, int, sqlite3_stmt **);
+SQLITE_PRIVATE int sqlite3Fts3ReadBlock(Fts3Table*, sqlite3_int64, char **, int*, int*);
+
+SQLITE_PRIVATE int sqlite3Fts3SelectDoctotal(Fts3Table *, sqlite3_stmt **);
+SQLITE_PRIVATE int sqlite3Fts3SelectDocsize(Fts3Table *, sqlite3_int64, sqlite3_stmt **);
+
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *);
+SQLITE_PRIVATE int sqlite3Fts3DeferToken(Fts3Cursor *, Fts3PhraseToken *, int);
+SQLITE_PRIVATE int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *);
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *);
+SQLITE_PRIVATE int sqlite3Fts3DeferredTokenList(Fts3DeferredToken *, char **, int *);
+#else
+# define sqlite3Fts3FreeDeferredTokens(x)
+# define sqlite3Fts3DeferToken(x,y,z) SQLITE_OK
+# define sqlite3Fts3CacheDeferredDoclists(x) SQLITE_OK
+# define sqlite3Fts3FreeDeferredDoclists(x)
+# define sqlite3Fts3DeferredTokenList(x,y,z) SQLITE_OK
+#endif
+
+SQLITE_PRIVATE void sqlite3Fts3SegmentsClose(Fts3Table *);
+SQLITE_PRIVATE int sqlite3Fts3MaxLevel(Fts3Table *, int *);
+
+/* Special values interpreted by sqlite3SegReaderCursor() */
+#define FTS3_SEGCURSOR_PENDING        -1
+#define FTS3_SEGCURSOR_ALL            -2
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStart(Fts3Table*, Fts3MultiSegReader*, Fts3SegFilter*);
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStep(Fts3Table *, Fts3MultiSegReader *);
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFinish(Fts3MultiSegReader *);
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderCursor(Fts3Table *,
+    int, int, int, const char *, int, int, int, Fts3MultiSegReader *);
+
+/* Flags allowed as part of the 4th argument to SegmentReaderIterate() */
+#define FTS3_SEGMENT_REQUIRE_POS   0x00000001
+#define FTS3_SEGMENT_IGNORE_EMPTY  0x00000002
+#define FTS3_SEGMENT_COLUMN_FILTER 0x00000004
+#define FTS3_SEGMENT_PREFIX        0x00000008
+#define FTS3_SEGMENT_SCAN          0x00000010
+#define FTS3_SEGMENT_FIRST         0x00000020
+
+/* Type passed as 4th argument to SegmentReaderIterate() */
+struct Fts3SegFilter {
+  const char *zTerm;
+  int nTerm;
+  int iCol;
+  int flags;
+};
+
+struct Fts3MultiSegReader {
+  /* Used internally by sqlite3Fts3SegReaderXXX() calls */
+  Fts3SegReader **apSegment;      /* Array of Fts3SegReader objects */
+  int nSegment;                   /* Size of apSegment array */
+  int nAdvance;                   /* How many seg-readers to advance */
+  Fts3SegFilter *pFilter;         /* Pointer to filter object */
+  char *aBuffer;                  /* Buffer to merge doclists in */
+  i64 nBuffer;                    /* Allocated size of aBuffer[] in bytes */
+
+  int iColFilter;                 /* If >=0, filter for this column */
+  int bRestart;
+
+  /* Used by fts3.c only. */
+  int nCost;                      /* Cost of running iterator */
+  int bLookup;                    /* True if a lookup of a single entry. */
+
+  /* Output values. Valid only after Fts3SegReaderStep() returns SQLITE_ROW. */
+  char *zTerm;                    /* Pointer to term buffer */
+  int nTerm;                      /* Size of zTerm in bytes */
+  char *aDoclist;                 /* Pointer to doclist buffer */
+  int nDoclist;                   /* Size of aDoclist[] in bytes */
+};
+
+SQLITE_PRIVATE int sqlite3Fts3Incrmerge(Fts3Table*,int,int);
+
+#define fts3GetVarint32(p, piVal) (                                           \
+  (*(u8*)(p)&0x80) ? sqlite3Fts3GetVarint32(p, piVal) : (*piVal=*(u8*)(p), 1) \
+)
+
+/* fts3.c */
+SQLITE_PRIVATE void sqlite3Fts3ErrMsg(char**,const char*,...);
+SQLITE_PRIVATE int sqlite3Fts3PutVarint(char *, sqlite3_int64);
+SQLITE_PRIVATE int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
+SQLITE_PRIVATE int sqlite3Fts3GetVarintU(const char *, sqlite_uint64 *);
+SQLITE_PRIVATE int sqlite3Fts3GetVarintBounded(const char*,const char*,sqlite3_int64*);
+SQLITE_PRIVATE int sqlite3Fts3GetVarint32(const char *, int *);
+SQLITE_PRIVATE int sqlite3Fts3VarintLen(sqlite3_uint64);
+SQLITE_PRIVATE void sqlite3Fts3Dequote(char *);
+SQLITE_PRIVATE void sqlite3Fts3DoclistPrev(int,char*,int,char**,sqlite3_int64*,int*,u8*);
+SQLITE_PRIVATE int sqlite3Fts3EvalPhraseStats(Fts3Cursor *, Fts3Expr *, u32 *);
+SQLITE_PRIVATE int sqlite3Fts3FirstFilter(sqlite3_int64, char *, int, char *);
+SQLITE_PRIVATE void sqlite3Fts3CreateStatTable(int*, Fts3Table*);
+SQLITE_PRIVATE int sqlite3Fts3EvalTestDeferred(Fts3Cursor *pCsr, int *pRc);
+SQLITE_PRIVATE int sqlite3Fts3ReadInt(const char *z, int *pnOut);
+
+/* fts3_tokenizer.c */
+SQLITE_PRIVATE const char *sqlite3Fts3NextToken(const char *, int *);
+SQLITE_PRIVATE int sqlite3Fts3InitHashTable(sqlite3 *, Fts3Hash *, const char *);
+SQLITE_PRIVATE int sqlite3Fts3InitTokenizer(Fts3Hash *pHash, const char *,
+    sqlite3_tokenizer **, char **
+);
+SQLITE_PRIVATE int sqlite3Fts3IsIdChar(char);
+
+/* fts3_snippet.c */
+SQLITE_PRIVATE void sqlite3Fts3Offsets(sqlite3_context*, Fts3Cursor*);
+SQLITE_PRIVATE void sqlite3Fts3Snippet(sqlite3_context *, Fts3Cursor *, const char *,
+  const char *, const char *, int, int
+);
+SQLITE_PRIVATE void sqlite3Fts3Matchinfo(sqlite3_context *, Fts3Cursor *, const char *);
+SQLITE_PRIVATE void sqlite3Fts3MIBufferFree(MatchinfoBuffer *p);
+
+/* fts3_expr.c */
+SQLITE_PRIVATE int sqlite3Fts3ExprParse(sqlite3_tokenizer *, int,
+  char **, int, int, int, const char *, int, Fts3Expr **, char **
+);
+SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *);
+#ifdef SQLITE_TEST
+SQLITE_PRIVATE int sqlite3Fts3ExprInitTestInterface(sqlite3 *db, Fts3Hash*);
+SQLITE_PRIVATE int sqlite3Fts3InitTerm(sqlite3 *db);
+#endif
+SQLITE_PRIVATE void *sqlite3Fts3MallocZero(i64 nByte);
+
+SQLITE_PRIVATE int sqlite3Fts3OpenTokenizer(sqlite3_tokenizer *, int, const char *, int,
+  sqlite3_tokenizer_cursor **
+);
+
+/* fts3_aux.c */
+SQLITE_PRIVATE int sqlite3Fts3InitAux(sqlite3 *db);
+
+SQLITE_PRIVATE void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *);
+
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrStart(
+    Fts3Table*, Fts3MultiSegReader*, int, const char*, int);
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrNext(
+    Fts3Table *, Fts3MultiSegReader *, sqlite3_int64 *, char **, int *);
+SQLITE_PRIVATE int sqlite3Fts3EvalPhrasePoslist(Fts3Cursor *, Fts3Expr *, int iCol, char **);
+SQLITE_PRIVATE int sqlite3Fts3MsrOvfl(Fts3Cursor *, Fts3MultiSegReader *, int *);
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr);
+SQLITE_PRIVATE int sqlite3Fts3MsrCancel(Fts3Cursor*, Fts3Expr*);
+
+/* fts3_tokenize_vtab.c */
+SQLITE_PRIVATE int sqlite3Fts3InitTok(sqlite3*, Fts3Hash *, void(*xDestroy)(void*));
+
+/* fts3_unicode2.c (functions generated by parsing unicode text files) */
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+SQLITE_PRIVATE int sqlite3FtsUnicodeFold(int, int);
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsalnum(int);
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsdiacritic(int);
+#endif
+
+SQLITE_PRIVATE int sqlite3Fts3ExprIterate(Fts3Expr*, int (*x)(Fts3Expr*,int,void*), void*);
+
+SQLITE_PRIVATE int sqlite3Fts3IntegrityCheck(Fts3Table *p, int *pbOk);
+
+#endif /* !SQLITE_CORE || SQLITE_ENABLE_FTS3 */
+#endif /* _FTSINT_H */
+
+/************** End of fts3Int.h *********************************************/
+/************** Continuing where we left off in fts3.c ***********************/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+#if defined(SQLITE_ENABLE_FTS3) && !defined(SQLITE_CORE)
+# define SQLITE_CORE 1
+#endif
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stddef.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+/* #include <stdarg.h> */
+
+/* #include "fts3.h" */
+#ifndef SQLITE_CORE
+/* # include "sqlite3ext.h" */
+  SQLITE_EXTENSION_INIT1
+#endif
+
+typedef struct Fts3HashWrapper Fts3HashWrapper;
+struct Fts3HashWrapper {
+  Fts3Hash hash;                  /* Hash table */
+  int nRef;                       /* Number of pointers to this object */
+};
+
+static int fts3EvalNext(Fts3Cursor *pCsr);
+static int fts3EvalStart(Fts3Cursor *pCsr);
+static int fts3TermSegReaderCursor(
+    Fts3Cursor *, const char *, int, int, Fts3MultiSegReader **);
+
+/*
+** This variable is set to false when running tests for which the on disk
+** structures should not be corrupt. Otherwise, true. If it is false, extra
+** assert() conditions in the fts3 code are activated - conditions that are
+** only true if it is guaranteed that the fts3 database is not corrupt.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_API int sqlite3_fts3_may_be_corrupt = 1;
+#endif
+
+/*
+** Write a 64-bit variable-length integer to memory starting at p[0].
+** The length of data written will be between 1 and FTS3_VARINT_MAX bytes.
+** The number of bytes written is returned.
+*/
+SQLITE_PRIVATE int sqlite3Fts3PutVarint(char *p, sqlite_int64 v){
+  unsigned char *q = (unsigned char *) p;
+  sqlite_uint64 vu = v;
+  do{
+    *q++ = (unsigned char) ((vu & 0x7f) | 0x80);
+    vu >>= 7;
+  }while( vu!=0 );
+  q[-1] &= 0x7f;  /* turn off high bit in final byte */
+  assert( q - (unsigned char *)p <= FTS3_VARINT_MAX );
+  return (int) (q - (unsigned char *)p);
+}
+
+#define GETVARINT_STEP(v, ptr, shift, mask1, mask2, var, ret) \
+  v = (v & mask1) | ( (*(const unsigned char*)(ptr++)) << shift );  \
+  if( (v & mask2)==0 ){ var = v; return ret; }
+#define GETVARINT_INIT(v, ptr, shift, mask1, mask2, var, ret) \
+  v = (*ptr++);                                               \
+  if( (v & mask2)==0 ){ var = v; return ret; }
+
+SQLITE_PRIVATE int sqlite3Fts3GetVarintU(const char *pBuf, sqlite_uint64 *v){
+  const unsigned char *p = (const unsigned char*)pBuf;
+  const unsigned char *pStart = p;
+  u32 a;
+  u64 b;
+  int shift;
+
+  GETVARINT_INIT(a, p, 0,  0x00,     0x80, *v, 1);
+  GETVARINT_STEP(a, p, 7,  0x7F,     0x4000, *v, 2);
+  GETVARINT_STEP(a, p, 14, 0x3FFF,   0x200000, *v, 3);
+  GETVARINT_STEP(a, p, 21, 0x1FFFFF, 0x10000000, *v, 4);
+  b = (a & 0x0FFFFFFF );
+
+  for(shift=28; shift<=63; shift+=7){
+    u64 c = *p++;
+    b += (c&0x7F) << shift;
+    if( (c & 0x80)==0 ) break;
+  }
+  *v = b;
+  return (int)(p - pStart);
+}
+
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read, or 0 on error.
+** The value is stored in *v.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarint(const char *pBuf, sqlite_int64 *v){
+  return sqlite3Fts3GetVarintU(pBuf, (sqlite3_uint64*)v);
+}
+
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0] and
+** not extending past pEnd[-1].
+** Return the number of bytes read, or 0 on error.
+** The value is stored in *v.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarintBounded(
+  const char *pBuf,
+  const char *pEnd,
+  sqlite_int64 *v
+){
+  const unsigned char *p = (const unsigned char*)pBuf;
+  const unsigned char *pStart = p;
+  const unsigned char *pX = (const unsigned char*)pEnd;
+  u64 b = 0;
+  int shift;
+  for(shift=0; shift<=63; shift+=7){
+    u64 c = p<pX ? *p : 0;
+    p++;
+    b += (c&0x7F) << shift;
+    if( (c & 0x80)==0 ) break;
+  }
+  *v = b;
+  return (int)(p - pStart);
+}
+
+/*
+** Similar to sqlite3Fts3GetVarint(), except that the output is truncated to
+** a non-negative 32-bit integer before it is returned.
+*/
+SQLITE_PRIVATE int sqlite3Fts3GetVarint32(const char *p, int *pi){
+  const unsigned char *ptr = (const unsigned char*)p;
+  u32 a;
+
+#ifndef fts3GetVarint32
+  GETVARINT_INIT(a, ptr, 0,  0x00,     0x80, *pi, 1);
+#else
+  a = (*ptr++);
+  assert( a & 0x80 );
+#endif
+
+  GETVARINT_STEP(a, ptr, 7,  0x7F,     0x4000, *pi, 2);
+  GETVARINT_STEP(a, ptr, 14, 0x3FFF,   0x200000, *pi, 3);
+  GETVARINT_STEP(a, ptr, 21, 0x1FFFFF, 0x10000000, *pi, 4);
+  a = (a & 0x0FFFFFFF );
+  *pi = (int)(a | ((u32)(*ptr & 0x07) << 28));
+  assert( 0==(a & 0x80000000) );
+  assert( *pi>=0 );
+  return 5;
+}
+
+/*
+** Return the number of bytes required to encode v as a varint
+*/
+SQLITE_PRIVATE int sqlite3Fts3VarintLen(sqlite3_uint64 v){
+  int i = 0;
+  do{
+    i++;
+    v >>= 7;
+  }while( v!=0 );
+  return i;
+}
+
+/*
+** Convert an SQL-style quoted string into a normal string by removing
+** the quote characters.  The conversion is done in-place.  If the
+** input does not begin with a quote character, then this routine
+** is a no-op.
+**
+** Examples:
+**
+**     "abc"   becomes   abc
+**     'xyz'   becomes   xyz
+**     [pqr]   becomes   pqr
+**     `mno`   becomes   mno
+**
+*/
+SQLITE_PRIVATE void sqlite3Fts3Dequote(char *z){
+  char quote;                     /* Quote character (if any ) */
+
+  quote = z[0];
+  if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){
+    int iIn = 1;                  /* Index of next byte to read from input */
+    int iOut = 0;                 /* Index of next byte to write to output */
+
+    /* If the first byte was a '[', then the close-quote character is a ']' */
+    if( quote=='[' ) quote = ']';
+
+    while( z[iIn] ){
+      if( z[iIn]==quote ){
+        if( z[iIn+1]!=quote ) break;
+        z[iOut++] = quote;
+        iIn += 2;
+      }else{
+        z[iOut++] = z[iIn++];
+      }
+    }
+    z[iOut] = '\0';
+  }
+}
+
+/*
+** Read a single varint from the doclist at *pp and advance *pp to point
+** to the first byte past the end of the varint.  Add the value of the varint
+** to *pVal.
+*/
+static void fts3GetDeltaVarint(char **pp, sqlite3_int64 *pVal){
+  sqlite3_int64 iVal;
+  *pp += sqlite3Fts3GetVarint(*pp, &iVal);
+  *pVal += iVal;
+}
+
+/*
+** When this function is called, *pp points to the first byte following a
+** varint that is part of a doclist (or position-list, or any other list
+** of varints). This function moves *pp to point to the start of that varint,
+** and sets *pVal by the varint value.
+**
+** Argument pStart points to the first byte of the doclist that the
+** varint is part of.
+*/
+static void fts3GetReverseVarint(
+  char **pp,
+  char *pStart,
+  sqlite3_int64 *pVal
+){
+  sqlite3_int64 iVal;
+  char *p;
+
+  /* Pointer p now points at the first byte past the varint we are
+  ** interested in. So, unless the doclist is corrupt, the 0x80 bit is
+  ** clear on character p[-1]. */
+  for(p = (*pp)-2; p>=pStart && *p&0x80; p--);
+  p++;
+  *pp = p;
+
+  sqlite3Fts3GetVarint(p, &iVal);
+  *pVal = iVal;
+}
+
+/*
+** The xDisconnect() virtual table method.
+*/
+static int fts3DisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int i;
+
+  assert( p->nPendingData==0 );
+  assert( p->pSegments==0 );
+
+  /* Free any prepared statements held */
+  sqlite3_finalize(p->pSeekStmt);
+  for(i=0; i<SizeofArray(p->aStmt); i++){
+    sqlite3_finalize(p->aStmt[i]);
+  }
+  sqlite3_free(p->zSegmentsTbl);
+  sqlite3_free(p->zReadExprlist);
+  sqlite3_free(p->zWriteExprlist);
+  sqlite3_free(p->zContentTbl);
+  sqlite3_free(p->zLanguageid);
+
+  /* Invoke the tokenizer destructor to free the tokenizer. */
+  p->pTokenizer->pModule->xDestroy(p->pTokenizer);
+
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Write an error message into *pzErr
+*/
+SQLITE_PRIVATE void sqlite3Fts3ErrMsg(char **pzErr, const char *zFormat, ...){
+  va_list ap;
+  sqlite3_free(*pzErr);
+  va_start(ap, zFormat);
+  *pzErr = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+}
+
+/*
+** Construct one or more SQL statements from the format string given
+** and then evaluate those statements. The success code is written
+** into *pRc.
+**
+** If *pRc is initially non-zero then this routine is a no-op.
+*/
+static void fts3DbExec(
+  int *pRc,              /* Success code */
+  sqlite3 *db,           /* Database in which to run SQL */
+  const char *zFormat,   /* Format string for SQL */
+  ...                    /* Arguments to the format string */
+){
+  va_list ap;
+  char *zSql;
+  if( *pRc ) return;
+  va_start(ap, zFormat);
+  zSql = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+  if( zSql==0 ){
+    *pRc = SQLITE_NOMEM;
+  }else{
+    *pRc = sqlite3_exec(db, zSql, 0, 0, 0);
+    sqlite3_free(zSql);
+  }
+}
+
+/*
+** The xDestroy() virtual table method.
+*/
+static int fts3DestroyMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int rc = SQLITE_OK;              /* Return code */
+  const char *zDb = p->zDb;        /* Name of database (e.g. "main", "temp") */
+  sqlite3 *db = p->db;             /* Database handle */
+
+  /* Drop the shadow tables */
+  fts3DbExec(&rc, db,
+    "DROP TABLE IF EXISTS %Q.'%q_segments';"
+    "DROP TABLE IF EXISTS %Q.'%q_segdir';"
+    "DROP TABLE IF EXISTS %Q.'%q_docsize';"
+    "DROP TABLE IF EXISTS %Q.'%q_stat';"
+    "%s DROP TABLE IF EXISTS %Q.'%q_content';",
+    zDb, p->zName,
+    zDb, p->zName,
+    zDb, p->zName,
+    zDb, p->zName,
+    (p->zContentTbl ? "--" : ""), zDb,p->zName
+  );
+
+  /* If everything has worked, invoke fts3DisconnectMethod() to free the
+  ** memory associated with the Fts3Table structure and return SQLITE_OK.
+  ** Otherwise, return an SQLite error code.
+  */
+  return (rc==SQLITE_OK ? fts3DisconnectMethod(pVtab) : rc);
+}
+
+
+/*
+** Invoke sqlite3_declare_vtab() to declare the schema for the FTS3 table
+** passed as the first argument. This is done as part of the xConnect()
+** and xCreate() methods.
+**
+** If *pRc is non-zero when this function is called, it is a no-op.
+** Otherwise, if an error occurs, an SQLite error code is stored in *pRc
+** before returning.
+*/
+static void fts3DeclareVtab(int *pRc, Fts3Table *p){
+  if( *pRc==SQLITE_OK ){
+    int i;                        /* Iterator variable */
+    int rc;                       /* Return code */
+    char *zSql;                   /* SQL statement passed to declare_vtab() */
+    char *zCols;                  /* List of user defined columns */
+    const char *zLanguageid;
+
+    zLanguageid = (p->zLanguageid ? p->zLanguageid : "__langid");
+    sqlite3_vtab_config(p->db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1);
+    sqlite3_vtab_config(p->db, SQLITE_VTAB_INNOCUOUS);
+
+    /* Create a list of user columns for the virtual table */
+    zCols = sqlite3_mprintf("%Q, ", p->azColumn[0]);
+    for(i=1; zCols && i<p->nColumn; i++){
+      zCols = sqlite3_mprintf("%z%Q, ", zCols, p->azColumn[i]);
+    }
+
+    /* Create the whole "CREATE TABLE" statement to pass to SQLite */
+    zSql = sqlite3_mprintf(
+        "CREATE TABLE x(%s %Q HIDDEN, docid HIDDEN, %Q HIDDEN)",
+        zCols, p->zName, zLanguageid
+    );
+    if( !zCols || !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_declare_vtab(p->db, zSql);
+    }
+
+    sqlite3_free(zSql);
+    sqlite3_free(zCols);
+    *pRc = rc;
+  }
+}
+
+/*
+** Create the %_stat table if it does not already exist.
+*/
+SQLITE_PRIVATE void sqlite3Fts3CreateStatTable(int *pRc, Fts3Table *p){
+  fts3DbExec(pRc, p->db,
+      "CREATE TABLE IF NOT EXISTS %Q.'%q_stat'"
+          "(id INTEGER PRIMARY KEY, value BLOB);",
+      p->zDb, p->zName
+  );
+  if( (*pRc)==SQLITE_OK ) p->bHasStat = 1;
+}
+
+/*
+** Create the backing store tables (%_content, %_segments and %_segdir)
+** required by the FTS3 table passed as the only argument. This is done
+** as part of the vtab xCreate() method.
+**
+** If the p->bHasDocsize boolean is true (indicating that this is an
+** FTS4 table, not an FTS3 table) then also create the %_docsize and
+** %_stat tables required by FTS4.
+*/
+static int fts3CreateTables(Fts3Table *p){
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Iterator variable */
+  sqlite3 *db = p->db;            /* The database connection */
+
+  if( p->zContentTbl==0 ){
+    const char *zLanguageid = p->zLanguageid;
+    char *zContentCols;           /* Columns of %_content table */
+
+    /* Create a list of user columns for the content table */
+    zContentCols = sqlite3_mprintf("docid INTEGER PRIMARY KEY");
+    for(i=0; zContentCols && i<p->nColumn; i++){
+      char *z = p->azColumn[i];
+      zContentCols = sqlite3_mprintf("%z, 'c%d%q'", zContentCols, i, z);
+    }
+    if( zLanguageid && zContentCols ){
+      zContentCols = sqlite3_mprintf("%z, langid", zContentCols, zLanguageid);
+    }
+    if( zContentCols==0 ) rc = SQLITE_NOMEM;
+
+    /* Create the content table */
+    fts3DbExec(&rc, db,
+       "CREATE TABLE %Q.'%q_content'(%s)",
+       p->zDb, p->zName, zContentCols
+    );
+    sqlite3_free(zContentCols);
+  }
+
+  /* Create other tables */
+  fts3DbExec(&rc, db,
+      "CREATE TABLE %Q.'%q_segments'(blockid INTEGER PRIMARY KEY, block BLOB);",
+      p->zDb, p->zName
+  );
+  fts3DbExec(&rc, db,
+      "CREATE TABLE %Q.'%q_segdir'("
+        "level INTEGER,"
+        "idx INTEGER,"
+        "start_block INTEGER,"
+        "leaves_end_block INTEGER,"
+        "end_block INTEGER,"
+        "root BLOB,"
+        "PRIMARY KEY(level, idx)"
+      ");",
+      p->zDb, p->zName
+  );
+  if( p->bHasDocsize ){
+    fts3DbExec(&rc, db,
+        "CREATE TABLE %Q.'%q_docsize'(docid INTEGER PRIMARY KEY, size BLOB);",
+        p->zDb, p->zName
+    );
+  }
+  assert( p->bHasStat==p->bFts4 );
+  if( p->bHasStat ){
+    sqlite3Fts3CreateStatTable(&rc, p);
+  }
+  return rc;
+}
+
+/*
+** Store the current database page-size in bytes in p->nPgsz.
+**
+** If *pRc is non-zero when this function is called, it is a no-op.
+** Otherwise, if an error occurs, an SQLite error code is stored in *pRc
+** before returning.
+*/
+static void fts3DatabasePageSize(int *pRc, Fts3Table *p){
+  if( *pRc==SQLITE_OK ){
+    int rc;                       /* Return code */
+    char *zSql;                   /* SQL text "PRAGMA %Q.page_size" */
+    sqlite3_stmt *pStmt;          /* Compiled "PRAGMA %Q.page_size" statement */
+
+    zSql = sqlite3_mprintf("PRAGMA %Q.page_size", p->zDb);
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare(p->db, zSql, -1, &pStmt, 0);
+      if( rc==SQLITE_OK ){
+        sqlite3_step(pStmt);
+        p->nPgsz = sqlite3_column_int(pStmt, 0);
+        rc = sqlite3_finalize(pStmt);
+      }else if( rc==SQLITE_AUTH ){
+        p->nPgsz = 1024;
+        rc = SQLITE_OK;
+      }
+    }
+    assert( p->nPgsz>0 || rc!=SQLITE_OK );
+    sqlite3_free(zSql);
+    *pRc = rc;
+  }
+}
+
+/*
+** "Special" FTS4 arguments are column specifications of the following form:
+**
+**   <key> = <value>
+**
+** There may not be whitespace surrounding the "=" character. The <value>
+** term may be quoted, but the <key> may not.
+*/
+static int fts3IsSpecialColumn(
+  const char *z,
+  int *pnKey,
+  char **pzValue
+){
+  char *zValue;
+  const char *zCsr = z;
+
+  while( *zCsr!='=' ){
+    if( *zCsr=='\0' ) return 0;
+    zCsr++;
+  }
+
+  *pnKey = (int)(zCsr-z);
+  zValue = sqlite3_mprintf("%s", &zCsr[1]);
+  if( zValue ){
+    sqlite3Fts3Dequote(zValue);
+  }
+  *pzValue = zValue;
+  return 1;
+}
+
+/*
+** Append the output of a printf() style formatting to an existing string.
+*/
+static void fts3Appendf(
+  int *pRc,                       /* IN/OUT: Error code */
+  char **pz,                      /* IN/OUT: Pointer to string buffer */
+  const char *zFormat,            /* Printf format string to append */
+  ...                             /* Arguments for printf format string */
+){
+  if( *pRc==SQLITE_OK ){
+    va_list ap;
+    char *z;
+    va_start(ap, zFormat);
+    z = sqlite3_vmprintf(zFormat, ap);
+    va_end(ap);
+    if( z && *pz ){
+      char *z2 = sqlite3_mprintf("%s%s", *pz, z);
+      sqlite3_free(z);
+      z = z2;
+    }
+    if( z==0 ) *pRc = SQLITE_NOMEM;
+    sqlite3_free(*pz);
+    *pz = z;
+  }
+}
+
+/*
+** Return a copy of input string zInput enclosed in double-quotes (") and
+** with all double quote characters escaped. For example:
+**
+**     fts3QuoteId("un \"zip\"")   ->    "un \"\"zip\"\""
+**
+** The pointer returned points to memory obtained from sqlite3_malloc(). It
+** is the callers responsibility to call sqlite3_free() to release this
+** memory.
+*/
+static char *fts3QuoteId(char const *zInput){
+  sqlite3_int64 nRet;
+  char *zRet;
+  nRet = 2 + (int)strlen(zInput)*2 + 1;
+  zRet = sqlite3_malloc64(nRet);
+  if( zRet ){
+    int i;
+    char *z = zRet;
+    *(z++) = '"';
+    for(i=0; zInput[i]; i++){
+      if( zInput[i]=='"' ) *(z++) = '"';
+      *(z++) = zInput[i];
+    }
+    *(z++) = '"';
+    *(z++) = '\0';
+  }
+  return zRet;
+}
+
+/*
+** Return a list of comma separated SQL expressions and a FROM clause that
+** could be used in a SELECT statement such as the following:
+**
+**     SELECT <list of expressions> FROM %_content AS x ...
+**
+** to return the docid, followed by each column of text data in order
+** from left to write. If parameter zFunc is not NULL, then instead of
+** being returned directly each column of text data is passed to an SQL
+** function named zFunc first. For example, if zFunc is "unzip" and the
+** table has the three user-defined columns "a", "b", and "c", the following
+** string is returned:
+**
+**     "docid, unzip(x.'a'), unzip(x.'b'), unzip(x.'c') FROM %_content AS x"
+**
+** The pointer returned points to a buffer allocated by sqlite3_malloc(). It
+** is the responsibility of the caller to eventually free it.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
+** a NULL pointer is returned). Otherwise, if an OOM error is encountered
+** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
+** no error occurs, *pRc is left unmodified.
+*/
+static char *fts3ReadExprList(Fts3Table *p, const char *zFunc, int *pRc){
+  char *zRet = 0;
+  char *zFree = 0;
+  char *zFunction;
+  int i;
+
+  if( p->zContentTbl==0 ){
+    if( !zFunc ){
+      zFunction = "";
+    }else{
+      zFree = zFunction = fts3QuoteId(zFunc);
+    }
+    fts3Appendf(pRc, &zRet, "docid");
+    for(i=0; i<p->nColumn; i++){
+      fts3Appendf(pRc, &zRet, ",%s(x.'c%d%q')", zFunction, i, p->azColumn[i]);
+    }
+    if( p->zLanguageid ){
+      fts3Appendf(pRc, &zRet, ", x.%Q", "langid");
+    }
+    sqlite3_free(zFree);
+  }else{
+    fts3Appendf(pRc, &zRet, "rowid");
+    for(i=0; i<p->nColumn; i++){
+      fts3Appendf(pRc, &zRet, ", x.'%q'", p->azColumn[i]);
+    }
+    if( p->zLanguageid ){
+      fts3Appendf(pRc, &zRet, ", x.%Q", p->zLanguageid);
+    }
+  }
+  fts3Appendf(pRc, &zRet, " FROM '%q'.'%q%s' AS x",
+      p->zDb,
+      (p->zContentTbl ? p->zContentTbl : p->zName),
+      (p->zContentTbl ? "" : "_content")
+  );
+  return zRet;
+}
+
+/*
+** Return a list of N comma separated question marks, where N is the number
+** of columns in the %_content table (one for the docid plus one for each
+** user-defined text column).
+**
+** If argument zFunc is not NULL, then all but the first question mark
+** is preceded by zFunc and an open bracket, and followed by a closed
+** bracket. For example, if zFunc is "zip" and the FTS3 table has three
+** user-defined text columns, the following string is returned:
+**
+**     "?, zip(?), zip(?), zip(?)"
+**
+** The pointer returned points to a buffer allocated by sqlite3_malloc(). It
+** is the responsibility of the caller to eventually free it.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and
+** a NULL pointer is returned). Otherwise, if an OOM error is encountered
+** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If
+** no error occurs, *pRc is left unmodified.
+*/
+static char *fts3WriteExprList(Fts3Table *p, const char *zFunc, int *pRc){
+  char *zRet = 0;
+  char *zFree = 0;
+  char *zFunction;
+  int i;
+
+  if( !zFunc ){
+    zFunction = "";
+  }else{
+    zFree = zFunction = fts3QuoteId(zFunc);
+  }
+  fts3Appendf(pRc, &zRet, "?");
+  for(i=0; i<p->nColumn; i++){
+    fts3Appendf(pRc, &zRet, ",%s(?)", zFunction);
+  }
+  if( p->zLanguageid ){
+    fts3Appendf(pRc, &zRet, ", ?");
+  }
+  sqlite3_free(zFree);
+  return zRet;
+}
+
+/*
+** Buffer z contains a positive integer value encoded as utf-8 text.
+** Decode this value and store it in *pnOut, returning the number of bytes
+** consumed. If an overflow error occurs return a negative value.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ReadInt(const char *z, int *pnOut){
+  u64 iVal = 0;
+  int i;
+  for(i=0; z[i]>='0' && z[i]<='9'; i++){
+    iVal = iVal*10 + (z[i] - '0');
+    if( iVal>0x7FFFFFFF ) return -1;
+  }
+  *pnOut = (int)iVal;
+  return i;
+}
+
+/*
+** This function interprets the string at (*pp) as a non-negative integer
+** value. It reads the integer and sets *pnOut to the value read, then
+** sets *pp to point to the byte immediately following the last byte of
+** the integer value.
+**
+** Only decimal digits ('0'..'9') may be part of an integer value.
+**
+** If *pp does not being with a decimal digit SQLITE_ERROR is returned and
+** the output value undefined. Otherwise SQLITE_OK is returned.
+**
+** This function is used when parsing the "prefix=" FTS4 parameter.
+*/
+static int fts3GobbleInt(const char **pp, int *pnOut){
+  const int MAX_NPREFIX = 10000000;
+  int nInt = 0;                   /* Output value */
+  int nByte;
+  nByte = sqlite3Fts3ReadInt(*pp, &nInt);
+  if( nInt>MAX_NPREFIX ){
+    nInt = 0;
+  }
+  if( nByte==0 ){
+    return SQLITE_ERROR;
+  }
+  *pnOut = nInt;
+  *pp += nByte;
+  return SQLITE_OK;
+}
+
+/*
+** This function is called to allocate an array of Fts3Index structures
+** representing the indexes maintained by the current FTS table. FTS tables
+** always maintain the main "terms" index, but may also maintain one or
+** more "prefix" indexes, depending on the value of the "prefix=" parameter
+** (if any) specified as part of the CREATE VIRTUAL TABLE statement.
+**
+** Argument zParam is passed the value of the "prefix=" option if one was
+** specified, or NULL otherwise.
+**
+** If no error occurs, SQLITE_OK is returned and *apIndex set to point to
+** the allocated array. *pnIndex is set to the number of elements in the
+** array. If an error does occur, an SQLite error code is returned.
+**
+** Regardless of whether or not an error is returned, it is the responsibility
+** of the caller to call sqlite3_free() on the output array to free it.
+*/
+static int fts3PrefixParameter(
+  const char *zParam,             /* ABC in prefix=ABC parameter to parse */
+  int *pnIndex,                   /* OUT: size of *apIndex[] array */
+  struct Fts3Index **apIndex      /* OUT: Array of indexes for this table */
+){
+  struct Fts3Index *aIndex;       /* Allocated array */
+  int nIndex = 1;                 /* Number of entries in array */
+
+  if( zParam && zParam[0] ){
+    const char *p;
+    nIndex++;
+    for(p=zParam; *p; p++){
+      if( *p==',' ) nIndex++;
+    }
+  }
+
+  aIndex = sqlite3_malloc64(sizeof(struct Fts3Index) * nIndex);
+  *apIndex = aIndex;
+  if( !aIndex ){
+    return SQLITE_NOMEM;
+  }
+
+  memset(aIndex, 0, sizeof(struct Fts3Index) * nIndex);
+  if( zParam ){
+    const char *p = zParam;
+    int i;
+    for(i=1; i<nIndex; i++){
+      int nPrefix = 0;
+      if( fts3GobbleInt(&p, &nPrefix) ) return SQLITE_ERROR;
+      assert( nPrefix>=0 );
+      if( nPrefix==0 ){
+        nIndex--;
+        i--;
+      }else{
+        aIndex[i].nPrefix = nPrefix;
+      }
+      p++;
+    }
+  }
+
+  *pnIndex = nIndex;
+  return SQLITE_OK;
+}
+
+/*
+** This function is called when initializing an FTS4 table that uses the
+** content=xxx option. It determines the number of and names of the columns
+** of the new FTS4 table.
+**
+** The third argument passed to this function is the value passed to the
+** config=xxx option (i.e. "xxx"). This function queries the database for
+** a table of that name. If found, the output variables are populated
+** as follows:
+**
+**   *pnCol:   Set to the number of columns table xxx has,
+**
+**   *pnStr:   Set to the total amount of space required to store a copy
+**             of each columns name, including the nul-terminator.
+**
+**   *pazCol:  Set to point to an array of *pnCol strings. Each string is
+**             the name of the corresponding column in table xxx. The array
+**             and its contents are allocated using a single allocation. It
+**             is the responsibility of the caller to free this allocation
+**             by eventually passing the *pazCol value to sqlite3_free().
+**
+** If the table cannot be found, an error code is returned and the output
+** variables are undefined. Or, if an OOM is encountered, SQLITE_NOMEM is
+** returned (and the output variables are undefined).
+*/
+static int fts3ContentColumns(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of db (i.e. "main", "temp" etc.) */
+  const char *zTbl,               /* Name of content table */
+  const char ***pazCol,           /* OUT: Malloc'd array of column names */
+  int *pnCol,                     /* OUT: Size of array *pazCol */
+  int *pnStr,                     /* OUT: Bytes of string content */
+  char **pzErr                    /* OUT: error message */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  char *zSql;                     /* "SELECT *" statement on zTbl */
+  sqlite3_stmt *pStmt = 0;        /* Compiled version of zSql */
+
+  zSql = sqlite3_mprintf("SELECT * FROM %Q.%Q", zDb, zTbl);
+  if( !zSql ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0);
+    if( rc!=SQLITE_OK ){
+      sqlite3Fts3ErrMsg(pzErr, "%s", sqlite3_errmsg(db));
+    }
+  }
+  sqlite3_free(zSql);
+
+  if( rc==SQLITE_OK ){
+    const char **azCol;           /* Output array */
+    sqlite3_int64 nStr = 0;       /* Size of all column names (incl. 0x00) */
+    int nCol;                     /* Number of table columns */
+    int i;                        /* Used to iterate through columns */
+
+    /* Loop through the returned columns. Set nStr to the number of bytes of
+    ** space required to store a copy of each column name, including the
+    ** nul-terminator byte.  */
+    nCol = sqlite3_column_count(pStmt);
+    for(i=0; i<nCol; i++){
+      const char *zCol = sqlite3_column_name(pStmt, i);
+      nStr += strlen(zCol) + 1;
+    }
+
+    /* Allocate and populate the array to return. */
+    azCol = (const char **)sqlite3_malloc64(sizeof(char *) * nCol + nStr);
+    if( azCol==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      char *p = (char *)&azCol[nCol];
+      for(i=0; i<nCol; i++){
+        const char *zCol = sqlite3_column_name(pStmt, i);
+        int n = (int)strlen(zCol)+1;
+        memcpy(p, zCol, n);
+        azCol[i] = p;
+        p += n;
+      }
+    }
+    sqlite3_finalize(pStmt);
+
+    /* Set the output variables. */
+    *pnCol = nCol;
+    *pnStr = nStr;
+    *pazCol = azCol;
+  }
+
+  return rc;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the FTS3 virtual table.
+**
+** The argv[] array contains the following:
+**
+**   argv[0]   -> module name  ("fts3" or "fts4")
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> "column name" and other module argument fields.
+*/
+static int fts3InitVtab(
+  int isCreate,                   /* True for xCreate, false for xConnect */
+  sqlite3 *db,                    /* The SQLite database connection */
+  void *pAux,                     /* Hash table containing tokenizers */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
+  char **pzErr                    /* Write any error message here */
+){
+  Fts3Hash *pHash = &((Fts3HashWrapper*)pAux)->hash;
+  Fts3Table *p = 0;               /* Pointer to allocated vtab */
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* Iterator variable */
+  sqlite3_int64 nByte;            /* Size of allocation used for *p */
+  int iCol;                       /* Column index */
+  int nString = 0;                /* Bytes required to hold all column names */
+  int nCol = 0;                   /* Number of columns in the FTS table */
+  char *zCsr;                     /* Space for holding column names */
+  int nDb;                        /* Bytes required to hold database name */
+  int nName;                      /* Bytes required to hold table name */
+  int isFts4 = (argv[0][3]=='4'); /* True for FTS4, false for FTS3 */
+  const char **aCol;              /* Array of column names */
+  sqlite3_tokenizer *pTokenizer = 0;        /* Tokenizer for this table */
+
+  int nIndex = 0;                 /* Size of aIndex[] array */
+  struct Fts3Index *aIndex = 0;   /* Array of indexes for this table */
+
+  /* The results of parsing supported FTS4 key=value options: */
+  int bNoDocsize = 0;             /* True to omit %_docsize table */
+  int bDescIdx = 0;               /* True to store descending indexes */
+  char *zPrefix = 0;              /* Prefix parameter value (or NULL) */
+  char *zCompress = 0;            /* compress=? parameter (or NULL) */
+  char *zUncompress = 0;          /* uncompress=? parameter (or NULL) */
+  char *zContent = 0;             /* content=? parameter (or NULL) */
+  char *zLanguageid = 0;          /* languageid=? parameter (or NULL) */
+  char **azNotindexed = 0;        /* The set of notindexed= columns */
+  int nNotindexed = 0;            /* Size of azNotindexed[] array */
+
+  assert( strlen(argv[0])==4 );
+  assert( (sqlite3_strnicmp(argv[0], "fts4", 4)==0 && isFts4)
+       || (sqlite3_strnicmp(argv[0], "fts3", 4)==0 && !isFts4)
+  );
+
+  nDb = (int)strlen(argv[1]) + 1;
+  nName = (int)strlen(argv[2]) + 1;
+
+  nByte = sizeof(const char *) * (argc-2);
+  aCol = (const char **)sqlite3_malloc64(nByte);
+  if( aCol ){
+    memset((void*)aCol, 0, nByte);
+    azNotindexed = (char **)sqlite3_malloc64(nByte);
+  }
+  if( azNotindexed ){
+    memset(azNotindexed, 0, nByte);
+  }
+  if( !aCol || !azNotindexed ){
+    rc = SQLITE_NOMEM;
+    goto fts3_init_out;
+  }
+
+  /* Loop through all of the arguments passed by the user to the FTS3/4
+  ** module (i.e. all the column names and special arguments). This loop
+  ** does the following:
+  **
+  **   + Figures out the number of columns the FTSX table will have, and
+  **     the number of bytes of space that must be allocated to store copies
+  **     of the column names.
+  **
+  **   + If there is a tokenizer specification included in the arguments,
+  **     initializes the tokenizer pTokenizer.
+  */
+  for(i=3; rc==SQLITE_OK && i<argc; i++){
+    char const *z = argv[i];
+    int nKey;
+    char *zVal;
+
+    /* Check if this is a tokenizer specification */
+    if( !pTokenizer
+     && strlen(z)>8
+     && 0==sqlite3_strnicmp(z, "tokenize", 8)
+     && 0==sqlite3Fts3IsIdChar(z[8])
+    ){
+      rc = sqlite3Fts3InitTokenizer(pHash, &z[9], &pTokenizer, pzErr);
+    }
+
+    /* Check if it is an FTS4 special argument. */
+    else if( isFts4 && fts3IsSpecialColumn(z, &nKey, &zVal) ){
+      struct Fts4Option {
+        const char *zOpt;
+        int nOpt;
+      } aFts4Opt[] = {
+        { "matchinfo",   9 },     /* 0 -> MATCHINFO */
+        { "prefix",      6 },     /* 1 -> PREFIX */
+        { "compress",    8 },     /* 2 -> COMPRESS */
+        { "uncompress", 10 },     /* 3 -> UNCOMPRESS */
+        { "order",       5 },     /* 4 -> ORDER */
+        { "content",     7 },     /* 5 -> CONTENT */
+        { "languageid", 10 },     /* 6 -> LANGUAGEID */
+        { "notindexed", 10 }      /* 7 -> NOTINDEXED */
+      };
+
+      int iOpt;
+      if( !zVal ){
+        rc = SQLITE_NOMEM;
+      }else{
+        for(iOpt=0; iOpt<SizeofArray(aFts4Opt); iOpt++){
+          struct Fts4Option *pOp = &aFts4Opt[iOpt];
+          if( nKey==pOp->nOpt && !sqlite3_strnicmp(z, pOp->zOpt, pOp->nOpt) ){
+            break;
+          }
+        }
+        switch( iOpt ){
+          case 0:               /* MATCHINFO */
+            if( strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "fts3", 4) ){
+              sqlite3Fts3ErrMsg(pzErr, "unrecognized matchinfo: %s", zVal);
+              rc = SQLITE_ERROR;
+            }
+            bNoDocsize = 1;
+            break;
+
+          case 1:               /* PREFIX */
+            sqlite3_free(zPrefix);
+            zPrefix = zVal;
+            zVal = 0;
+            break;
+
+          case 2:               /* COMPRESS */
+            sqlite3_free(zCompress);
+            zCompress = zVal;
+            zVal = 0;
+            break;
+
+          case 3:               /* UNCOMPRESS */
+            sqlite3_free(zUncompress);
+            zUncompress = zVal;
+            zVal = 0;
+            break;
+
+          case 4:               /* ORDER */
+            if( (strlen(zVal)!=3 || sqlite3_strnicmp(zVal, "asc", 3))
+             && (strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "desc", 4))
+            ){
+              sqlite3Fts3ErrMsg(pzErr, "unrecognized order: %s", zVal);
+              rc = SQLITE_ERROR;
+            }
+            bDescIdx = (zVal[0]=='d' || zVal[0]=='D');
+            break;
+
+          case 5:              /* CONTENT */
+            sqlite3_free(zContent);
+            zContent = zVal;
+            zVal = 0;
+            break;
+
+          case 6:              /* LANGUAGEID */
+            assert( iOpt==6 );
+            sqlite3_free(zLanguageid);
+            zLanguageid = zVal;
+            zVal = 0;
+            break;
+
+          case 7:              /* NOTINDEXED */
+            azNotindexed[nNotindexed++] = zVal;
+            zVal = 0;
+            break;
+
+          default:
+            assert( iOpt==SizeofArray(aFts4Opt) );
+            sqlite3Fts3ErrMsg(pzErr, "unrecognized parameter: %s", z);
+            rc = SQLITE_ERROR;
+            break;
+        }
+        sqlite3_free(zVal);
+      }
+    }
+
+    /* Otherwise, the argument is a column name. */
+    else {
+      nString += (int)(strlen(z) + 1);
+      aCol[nCol++] = z;
+    }
+  }
+
+  /* If a content=xxx option was specified, the following:
+  **
+  **   1. Ignore any compress= and uncompress= options.
+  **
+  **   2. If no column names were specified as part of the CREATE VIRTUAL
+  **      TABLE statement, use all columns from the content table.
+  */
+  if( rc==SQLITE_OK && zContent ){
+    sqlite3_free(zCompress);
+    sqlite3_free(zUncompress);
+    zCompress = 0;
+    zUncompress = 0;
+    if( nCol==0 ){
+      sqlite3_free((void*)aCol);
+      aCol = 0;
+      rc = fts3ContentColumns(db, argv[1], zContent,&aCol,&nCol,&nString,pzErr);
+
+      /* If a languageid= option was specified, remove the language id
+      ** column from the aCol[] array. */
+      if( rc==SQLITE_OK && zLanguageid ){
+        int j;
+        for(j=0; j<nCol; j++){
+          if( sqlite3_stricmp(zLanguageid, aCol[j])==0 ){
+            int k;
+            for(k=j; k<nCol; k++) aCol[k] = aCol[k+1];
+            nCol--;
+            break;
+          }
+        }
+      }
+    }
+  }
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  if( nCol==0 ){
+    assert( nString==0 );
+    aCol[0] = "content";
+    nString = 8;
+    nCol = 1;
+  }
+
+  if( pTokenizer==0 ){
+    rc = sqlite3Fts3InitTokenizer(pHash, "simple", &pTokenizer, pzErr);
+    if( rc!=SQLITE_OK ) goto fts3_init_out;
+  }
+  assert( pTokenizer );
+
+  rc = fts3PrefixParameter(zPrefix, &nIndex, &aIndex);
+  if( rc==SQLITE_ERROR ){
+    assert( zPrefix );
+    sqlite3Fts3ErrMsg(pzErr, "error parsing prefix parameter: %s", zPrefix);
+  }
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  /* Allocate and populate the Fts3Table structure. */
+  nByte = sizeof(Fts3Table) +                  /* Fts3Table */
+          nCol * sizeof(char *) +              /* azColumn */
+          nIndex * sizeof(struct Fts3Index) +  /* aIndex */
+          nCol * sizeof(u8) +                  /* abNotindexed */
+          nName +                              /* zName */
+          nDb +                                /* zDb */
+          nString;                             /* Space for azColumn strings */
+  p = (Fts3Table*)sqlite3_malloc64(nByte);
+  if( p==0 ){
+    rc = SQLITE_NOMEM;
+    goto fts3_init_out;
+  }
+  memset(p, 0, nByte);
+  p->db = db;
+  p->nColumn = nCol;
+  p->nPendingData = 0;
+  p->azColumn = (char **)&p[1];
+  p->pTokenizer = pTokenizer;
+  p->nMaxPendingData = FTS3_MAX_PENDING_DATA;
+  p->bHasDocsize = (isFts4 && bNoDocsize==0);
+  p->bHasStat = (u8)isFts4;
+  p->bFts4 = (u8)isFts4;
+  p->bDescIdx = (u8)bDescIdx;
+  p->nAutoincrmerge = 0xff;   /* 0xff means setting unknown */
+  p->zContentTbl = zContent;
+  p->zLanguageid = zLanguageid;
+  zContent = 0;
+  zLanguageid = 0;
+  TESTONLY( p->inTransaction = -1 );
+  TESTONLY( p->mxSavepoint = -1 );
+
+  p->aIndex = (struct Fts3Index *)&p->azColumn[nCol];
+  memcpy(p->aIndex, aIndex, sizeof(struct Fts3Index) * nIndex);
+  p->nIndex = nIndex;
+  for(i=0; i<nIndex; i++){
+    fts3HashInit(&p->aIndex[i].hPending, FTS3_HASH_STRING, 1);
+  }
+  p->abNotindexed = (u8 *)&p->aIndex[nIndex];
+
+  /* Fill in the zName and zDb fields of the vtab structure. */
+  zCsr = (char *)&p->abNotindexed[nCol];
+  p->zName = zCsr;
+  memcpy(zCsr, argv[2], nName);
+  zCsr += nName;
+  p->zDb = zCsr;
+  memcpy(zCsr, argv[1], nDb);
+  zCsr += nDb;
+
+  /* Fill in the azColumn array */
+  for(iCol=0; iCol<nCol; iCol++){
+    char *z;
+    int n = 0;
+    z = (char *)sqlite3Fts3NextToken(aCol[iCol], &n);
+    if( n>0 ){
+      memcpy(zCsr, z, n);
+    }
+    zCsr[n] = '\0';
+    sqlite3Fts3Dequote(zCsr);
+    p->azColumn[iCol] = zCsr;
+    zCsr += n+1;
+    assert( zCsr <= &((char *)p)[nByte] );
+  }
+
+  /* Fill in the abNotindexed array */
+  for(iCol=0; iCol<nCol; iCol++){
+    int n = (int)strlen(p->azColumn[iCol]);
+    for(i=0; i<nNotindexed; i++){
+      char *zNot = azNotindexed[i];
+      if( zNot && n==(int)strlen(zNot)
+       && 0==sqlite3_strnicmp(p->azColumn[iCol], zNot, n)
+      ){
+        p->abNotindexed[iCol] = 1;
+        sqlite3_free(zNot);
+        azNotindexed[i] = 0;
+      }
+    }
+  }
+  for(i=0; i<nNotindexed; i++){
+    if( azNotindexed[i] ){
+      sqlite3Fts3ErrMsg(pzErr, "no such column: %s", azNotindexed[i]);
+      rc = SQLITE_ERROR;
+    }
+  }
+
+  if( rc==SQLITE_OK && (zCompress==0)!=(zUncompress==0) ){
+    char const *zMiss = (zCompress==0 ? "compress" : "uncompress");
+    rc = SQLITE_ERROR;
+    sqlite3Fts3ErrMsg(pzErr, "missing %s parameter in fts4 constructor", zMiss);
+  }
+  p->zReadExprlist = fts3ReadExprList(p, zUncompress, &rc);
+  p->zWriteExprlist = fts3WriteExprList(p, zCompress, &rc);
+  if( rc!=SQLITE_OK ) goto fts3_init_out;
+
+  /* If this is an xCreate call, create the underlying tables in the
+  ** database. TODO: For xConnect(), it could verify that said tables exist.
+  */
+  if( isCreate ){
+    rc = fts3CreateTables(p);
+  }
+
+  /* Check to see if a legacy fts3 table has been "upgraded" by the
+  ** addition of a %_stat table so that it can use incremental merge.
+  */
+  if( !isFts4 && !isCreate ){
+    p->bHasStat = 2;
+  }
+
+  /* Figure out the page-size for the database. This is required in order to
+  ** estimate the cost of loading large doclists from the database.  */
+  fts3DatabasePageSize(&rc, p);
+  p->nNodeSize = p->nPgsz-35;
+
+#if defined(SQLITE_DEBUG)||defined(SQLITE_TEST)
+  p->nMergeCount = FTS3_MERGE_COUNT;
+#endif
+
+  /* Declare the table schema to SQLite. */
+  fts3DeclareVtab(&rc, p);
+
+fts3_init_out:
+  sqlite3_free(zPrefix);
+  sqlite3_free(aIndex);
+  sqlite3_free(zCompress);
+  sqlite3_free(zUncompress);
+  sqlite3_free(zContent);
+  sqlite3_free(zLanguageid);
+  for(i=0; i<nNotindexed; i++) sqlite3_free(azNotindexed[i]);
+  sqlite3_free((void *)aCol);
+  sqlite3_free((void *)azNotindexed);
+  if( rc!=SQLITE_OK ){
+    if( p ){
+      fts3DisconnectMethod((sqlite3_vtab *)p);
+    }else if( pTokenizer ){
+      pTokenizer->pModule->xDestroy(pTokenizer);
+    }
+  }else{
+    assert( p->pSegments==0 );
+    *ppVTab = &p->base;
+  }
+  return rc;
+}
+
+/*
+** The xConnect() and xCreate() methods for the virtual table. All the
+** work is done in function fts3InitVtab().
+*/
+static int fts3ConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts3InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr);
+}
+static int fts3CreateMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts3InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr);
+}
+
+/*
+** Set the pIdxInfo->estimatedRows variable to nRow. Unless this
+** extension is currently being used by a version of SQLite too old to
+** support estimatedRows. In that case this function is a no-op.
+*/
+static void fts3SetEstimatedRows(sqlite3_index_info *pIdxInfo, i64 nRow){
+#if SQLITE_VERSION_NUMBER>=3008002
+  if( sqlite3_libversion_number()>=3008002 ){
+    pIdxInfo->estimatedRows = nRow;
+  }
+#endif
+}
+
+/*
+** Set the SQLITE_INDEX_SCAN_UNIQUE flag in pIdxInfo->flags. Unless this
+** extension is currently being used by a version of SQLite too old to
+** support index-info flags. In that case this function is a no-op.
+*/
+static void fts3SetUniqueFlag(sqlite3_index_info *pIdxInfo){
+#if SQLITE_VERSION_NUMBER>=3008012
+  if( sqlite3_libversion_number()>=3008012 ){
+    pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_UNIQUE;
+  }
+#endif
+}
+
+/*
+** Implementation of the xBestIndex method for FTS3 tables. There
+** are three possible strategies, in order of preference:
+**
+**   1. Direct lookup by rowid or docid.
+**   2. Full-text search using a MATCH operator on a non-docid column.
+**   3. Linear scan of %_content table.
+*/
+static int fts3BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
+  Fts3Table *p = (Fts3Table *)pVTab;
+  int i;                          /* Iterator variable */
+  int iCons = -1;                 /* Index of constraint to use */
+
+  int iLangidCons = -1;           /* Index of langid=x constraint, if present */
+  int iDocidGe = -1;              /* Index of docid>=x constraint, if present */
+  int iDocidLe = -1;              /* Index of docid<=x constraint, if present */
+  int iIdx;
+
+  if( p->bLock ){
+    return SQLITE_ERROR;
+  }
+
+  /* By default use a full table scan. This is an expensive option,
+  ** so search through the constraints to see if a more efficient
+  ** strategy is possible.
+  */
+  pInfo->idxNum = FTS3_FULLSCAN_SEARCH;
+  pInfo->estimatedCost = 5000000;
+  for(i=0; i<pInfo->nConstraint; i++){
+    int bDocid;                 /* True if this constraint is on docid */
+    struct sqlite3_index_constraint *pCons = &pInfo->aConstraint[i];
+    if( pCons->usable==0 ){
+      if( pCons->op==SQLITE_INDEX_CONSTRAINT_MATCH ){
+        /* There exists an unusable MATCH constraint. This means that if
+        ** the planner does elect to use the results of this call as part
+        ** of the overall query plan the user will see an "unable to use
+        ** function MATCH in the requested context" error. To discourage
+        ** this, return a very high cost here.  */
+        pInfo->idxNum = FTS3_FULLSCAN_SEARCH;
+        pInfo->estimatedCost = 1e50;
+        fts3SetEstimatedRows(pInfo, ((sqlite3_int64)1) << 50);
+        return SQLITE_OK;
+      }
+      continue;
+    }
+
+    bDocid = (pCons->iColumn<0 || pCons->iColumn==p->nColumn+1);
+
+    /* A direct lookup on the rowid or docid column. Assign a cost of 1.0. */
+    if( iCons<0 && pCons->op==SQLITE_INDEX_CONSTRAINT_EQ && bDocid ){
+      pInfo->idxNum = FTS3_DOCID_SEARCH;
+      pInfo->estimatedCost = 1.0;
+      iCons = i;
+    }
+
+    /* A MATCH constraint. Use a full-text search.
+    **
+    ** If there is more than one MATCH constraint available, use the first
+    ** one encountered. If there is both a MATCH constraint and a direct
+    ** rowid/docid lookup, prefer the MATCH strategy. This is done even
+    ** though the rowid/docid lookup is faster than a MATCH query, selecting
+    ** it would lead to an "unable to use function MATCH in the requested
+    ** context" error.
+    */
+    if( pCons->op==SQLITE_INDEX_CONSTRAINT_MATCH
+     && pCons->iColumn>=0 && pCons->iColumn<=p->nColumn
+    ){
+      pInfo->idxNum = FTS3_FULLTEXT_SEARCH + pCons->iColumn;
+      pInfo->estimatedCost = 2.0;
+      iCons = i;
+    }
+
+    /* Equality constraint on the langid column */
+    if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ
+     && pCons->iColumn==p->nColumn + 2
+    ){
+      iLangidCons = i;
+    }
+
+    if( bDocid ){
+      switch( pCons->op ){
+        case SQLITE_INDEX_CONSTRAINT_GE:
+        case SQLITE_INDEX_CONSTRAINT_GT:
+          iDocidGe = i;
+          break;
+
+        case SQLITE_INDEX_CONSTRAINT_LE:
+        case SQLITE_INDEX_CONSTRAINT_LT:
+          iDocidLe = i;
+          break;
+      }
+    }
+  }
+
+  /* If using a docid=? or rowid=? strategy, set the UNIQUE flag. */
+  if( pInfo->idxNum==FTS3_DOCID_SEARCH ) fts3SetUniqueFlag(pInfo);
+
+  iIdx = 1;
+  if( iCons>=0 ){
+    pInfo->aConstraintUsage[iCons].argvIndex = iIdx++;
+    pInfo->aConstraintUsage[iCons].omit = 1;
+  }
+  if( iLangidCons>=0 ){
+    pInfo->idxNum |= FTS3_HAVE_LANGID;
+    pInfo->aConstraintUsage[iLangidCons].argvIndex = iIdx++;
+  }
+  if( iDocidGe>=0 ){
+    pInfo->idxNum |= FTS3_HAVE_DOCID_GE;
+    pInfo->aConstraintUsage[iDocidGe].argvIndex = iIdx++;
+  }
+  if( iDocidLe>=0 ){
+    pInfo->idxNum |= FTS3_HAVE_DOCID_LE;
+    pInfo->aConstraintUsage[iDocidLe].argvIndex = iIdx++;
+  }
+
+  /* Regardless of the strategy selected, FTS can deliver rows in rowid (or
+  ** docid) order. Both ascending and descending are possible.
+  */
+  if( pInfo->nOrderBy==1 ){
+    struct sqlite3_index_orderby *pOrder = &pInfo->aOrderBy[0];
+    if( pOrder->iColumn<0 || pOrder->iColumn==p->nColumn+1 ){
+      if( pOrder->desc ){
+        pInfo->idxStr = "DESC";
+      }else{
+        pInfo->idxStr = "ASC";
+      }
+      pInfo->orderByConsumed = 1;
+    }
+  }
+
+  assert( p->pSegments==0 );
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xOpen method.
+*/
+static int fts3OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  sqlite3_vtab_cursor *pCsr;               /* Allocated cursor */
+
+  UNUSED_PARAMETER(pVTab);
+
+  /* Allocate a buffer large enough for an Fts3Cursor structure. If the
+  ** allocation succeeds, zero it and return SQLITE_OK. Otherwise,
+  ** if the allocation fails, return SQLITE_NOMEM.
+  */
+  *ppCsr = pCsr = (sqlite3_vtab_cursor *)sqlite3_malloc(sizeof(Fts3Cursor));
+  if( !pCsr ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(Fts3Cursor));
+  return SQLITE_OK;
+}
+
+/*
+** Finalize the statement handle at pCsr->pStmt.
+**
+** Or, if that statement handle is one created by fts3CursorSeekStmt(),
+** and the Fts3Table.pSeekStmt slot is currently NULL, save the statement
+** pointer there instead of finalizing it.
+*/
+static void fts3CursorFinalizeStmt(Fts3Cursor *pCsr){
+  if( pCsr->bSeekStmt ){
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+    if( p->pSeekStmt==0 ){
+      p->pSeekStmt = pCsr->pStmt;
+      sqlite3_reset(pCsr->pStmt);
+      pCsr->pStmt = 0;
+    }
+    pCsr->bSeekStmt = 0;
+  }
+  sqlite3_finalize(pCsr->pStmt);
+}
+
+/*
+** Free all resources currently held by the cursor passed as the only
+** argument.
+*/
+static void fts3ClearCursor(Fts3Cursor *pCsr){
+  fts3CursorFinalizeStmt(pCsr);
+  sqlite3Fts3FreeDeferredTokens(pCsr);
+  sqlite3_free(pCsr->aDoclist);
+  sqlite3Fts3MIBufferFree(pCsr->pMIBuffer);
+  sqlite3Fts3ExprFree(pCsr->pExpr);
+  memset(&(&pCsr->base)[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor));
+}
+
+/*
+** Close the cursor.  For additional information see the documentation
+** on the xClose method of the virtual table interface.
+*/
+static int fts3CloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  fts3ClearCursor(pCsr);
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** If pCsr->pStmt has not been prepared (i.e. if pCsr->pStmt==0), then
+** compose and prepare an SQL statement of the form:
+**
+**    "SELECT <columns> FROM %_content WHERE rowid = ?"
+**
+** (or the equivalent for a content=xxx table) and set pCsr->pStmt to
+** it. If an error occurs, return an SQLite error code.
+*/
+static int fts3CursorSeekStmt(Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;
+  if( pCsr->pStmt==0 ){
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+    char *zSql;
+    if( p->pSeekStmt ){
+      pCsr->pStmt = p->pSeekStmt;
+      p->pSeekStmt = 0;
+    }else{
+      zSql = sqlite3_mprintf("SELECT %s WHERE rowid = ?", p->zReadExprlist);
+      if( !zSql ) return SQLITE_NOMEM;
+      p->bLock++;
+      rc = sqlite3_prepare_v3(
+          p->db, zSql,-1,SQLITE_PREPARE_PERSISTENT,&pCsr->pStmt,0
+      );
+      p->bLock--;
+      sqlite3_free(zSql);
+    }
+    if( rc==SQLITE_OK ) pCsr->bSeekStmt = 1;
+  }
+  return rc;
+}
+
+/*
+** Position the pCsr->pStmt statement so that it is on the row
+** of the %_content table that contains the last match.  Return
+** SQLITE_OK on success.
+*/
+static int fts3CursorSeek(sqlite3_context *pContext, Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;
+  if( pCsr->isRequireSeek ){
+    rc = fts3CursorSeekStmt(pCsr);
+    if( rc==SQLITE_OK ){
+      Fts3Table *pTab = (Fts3Table*)pCsr->base.pVtab;
+      pTab->bLock++;
+      sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);
+      pCsr->isRequireSeek = 0;
+      if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){
+        pTab->bLock--;
+        return SQLITE_OK;
+      }else{
+        pTab->bLock--;
+        rc = sqlite3_reset(pCsr->pStmt);
+        if( rc==SQLITE_OK && ((Fts3Table *)pCsr->base.pVtab)->zContentTbl==0 ){
+          /* If no row was found and no error has occurred, then the %_content
+          ** table is missing a row that is present in the full-text index.
+          ** The data structures are corrupt.  */
+          rc = FTS_CORRUPT_VTAB;
+          pCsr->isEof = 1;
+        }
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK && pContext ){
+    sqlite3_result_error_code(pContext, rc);
+  }
+  return rc;
+}
+
+/*
+** This function is used to process a single interior node when searching
+** a b-tree for a term or term prefix. The node data is passed to this
+** function via the zNode/nNode parameters. The term to search for is
+** passed in zTerm/nTerm.
+**
+** If piFirst is not NULL, then this function sets *piFirst to the blockid
+** of the child node that heads the sub-tree that may contain the term.
+**
+** If piLast is not NULL, then *piLast is set to the right-most child node
+** that heads a sub-tree that may contain a term for which zTerm/nTerm is
+** a prefix.
+**
+** If an OOM error occurs, SQLITE_NOMEM is returned. Otherwise, SQLITE_OK.
+*/
+static int fts3ScanInteriorNode(
+  const char *zTerm,              /* Term to select leaves for */
+  int nTerm,                      /* Size of term zTerm in bytes */
+  const char *zNode,              /* Buffer containing segment interior node */
+  int nNode,                      /* Size of buffer at zNode */
+  sqlite3_int64 *piFirst,         /* OUT: Selected child node */
+  sqlite3_int64 *piLast           /* OUT: Selected child node */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  const char *zCsr = zNode;       /* Cursor to iterate through node */
+  const char *zEnd = &zCsr[nNode];/* End of interior node buffer */
+  char *zBuffer = 0;              /* Buffer to load terms into */
+  i64 nAlloc = 0;                 /* Size of allocated buffer */
+  int isFirstTerm = 1;            /* True when processing first term on page */
+  u64 iChild;                     /* Block id of child node to descend to */
+  int nBuffer = 0;                /* Total term size */
+
+  /* Skip over the 'height' varint that occurs at the start of every
+  ** interior node. Then load the blockid of the left-child of the b-tree
+  ** node into variable iChild.
+  **
+  ** Even if the data structure on disk is corrupted, this (reading two
+  ** varints from the buffer) does not risk an overread. If zNode is a
+  ** root node, then the buffer comes from a SELECT statement. SQLite does
+  ** not make this guarantee explicitly, but in practice there are always
+  ** either more than 20 bytes of allocated space following the nNode bytes of
+  ** contents, or two zero bytes. Or, if the node is read from the %_segments
+  ** table, then there are always 20 bytes of zeroed padding following the
+  ** nNode bytes of content (see sqlite3Fts3ReadBlock() for details).
+  */
+  zCsr += sqlite3Fts3GetVarintU(zCsr, &iChild);
+  zCsr += sqlite3Fts3GetVarintU(zCsr, &iChild);
+  if( zCsr>zEnd ){
+    return FTS_CORRUPT_VTAB;
+  }
+
+  while( zCsr<zEnd && (piFirst || piLast) ){
+    int cmp;                      /* memcmp() result */
+    int nSuffix;                  /* Size of term suffix */
+    int nPrefix = 0;              /* Size of term prefix */
+
+    /* Load the next term on the node into zBuffer. Use realloc() to expand
+    ** the size of zBuffer if required.  */
+    if( !isFirstTerm ){
+      zCsr += fts3GetVarint32(zCsr, &nPrefix);
+      if( nPrefix>nBuffer ){
+        rc = FTS_CORRUPT_VTAB;
+        goto finish_scan;
+      }
+    }
+    isFirstTerm = 0;
+    zCsr += fts3GetVarint32(zCsr, &nSuffix);
+
+    assert( nPrefix>=0 && nSuffix>=0 );
+    if( nPrefix>zCsr-zNode || nSuffix>zEnd-zCsr || nSuffix==0 ){
+      rc = FTS_CORRUPT_VTAB;
+      goto finish_scan;
+    }
+    if( (i64)nPrefix+nSuffix>nAlloc ){
+      char *zNew;
+      nAlloc = ((i64)nPrefix+nSuffix) * 2;
+      zNew = (char *)sqlite3_realloc64(zBuffer, nAlloc);
+      if( !zNew ){
+        rc = SQLITE_NOMEM;
+        goto finish_scan;
+      }
+      zBuffer = zNew;
+    }
+    assert( zBuffer );
+    memcpy(&zBuffer[nPrefix], zCsr, nSuffix);
+    nBuffer = nPrefix + nSuffix;
+    zCsr += nSuffix;
+
+    /* Compare the term we are searching for with the term just loaded from
+    ** the interior node. If the specified term is greater than or equal
+    ** to the term from the interior node, then all terms on the sub-tree
+    ** headed by node iChild are smaller than zTerm. No need to search
+    ** iChild.
+    **
+    ** If the interior node term is larger than the specified term, then
+    ** the tree headed by iChild may contain the specified term.
+    */
+    cmp = memcmp(zTerm, zBuffer, (nBuffer>nTerm ? nTerm : nBuffer));
+    if( piFirst && (cmp<0 || (cmp==0 && nBuffer>nTerm)) ){
+      *piFirst = (i64)iChild;
+      piFirst = 0;
+    }
+
+    if( piLast && cmp<0 ){
+      *piLast = (i64)iChild;
+      piLast = 0;
+    }
+
+    iChild++;
+  };
+
+  if( piFirst ) *piFirst = (i64)iChild;
+  if( piLast ) *piLast = (i64)iChild;
+
+ finish_scan:
+  sqlite3_free(zBuffer);
+  return rc;
+}
+
+
+/*
+** The buffer pointed to by argument zNode (size nNode bytes) contains an
+** interior node of a b-tree segment. The zTerm buffer (size nTerm bytes)
+** contains a term. This function searches the sub-tree headed by the zNode
+** node for the range of leaf nodes that may contain the specified term
+** or terms for which the specified term is a prefix.
+**
+** If piLeaf is not NULL, then *piLeaf is set to the blockid of the
+** left-most leaf node in the tree that may contain the specified term.
+** If piLeaf2 is not NULL, then *piLeaf2 is set to the blockid of the
+** right-most leaf node that may contain a term for which the specified
+** term is a prefix.
+**
+** It is possible that the range of returned leaf nodes does not contain
+** the specified term or any terms for which it is a prefix. However, if the
+** segment does contain any such terms, they are stored within the identified
+** range. Because this function only inspects interior segment nodes (and
+** never loads leaf nodes into memory), it is not possible to be sure.
+**
+** If an error occurs, an error code other than SQLITE_OK is returned.
+*/
+static int fts3SelectLeaf(
+  Fts3Table *p,                   /* Virtual table handle */
+  const char *zTerm,              /* Term to select leaves for */
+  int nTerm,                      /* Size of term zTerm in bytes */
+  const char *zNode,              /* Buffer containing segment interior node */
+  int nNode,                      /* Size of buffer at zNode */
+  sqlite3_int64 *piLeaf,          /* Selected leaf node */
+  sqlite3_int64 *piLeaf2          /* Selected leaf node */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int iHeight;                    /* Height of this node in tree */
+
+  assert( piLeaf || piLeaf2 );
+
+  fts3GetVarint32(zNode, &iHeight);
+  rc = fts3ScanInteriorNode(zTerm, nTerm, zNode, nNode, piLeaf, piLeaf2);
+  assert_fts3_nc( !piLeaf2 || !piLeaf || rc!=SQLITE_OK || (*piLeaf<=*piLeaf2) );
+
+  if( rc==SQLITE_OK && iHeight>1 ){
+    char *zBlob = 0;              /* Blob read from %_segments table */
+    int nBlob = 0;                /* Size of zBlob in bytes */
+
+    if( piLeaf && piLeaf2 && (*piLeaf!=*piLeaf2) ){
+      rc = sqlite3Fts3ReadBlock(p, *piLeaf, &zBlob, &nBlob, 0);
+      if( rc==SQLITE_OK ){
+        rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, 0);
+      }
+      sqlite3_free(zBlob);
+      piLeaf = 0;
+      zBlob = 0;
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts3ReadBlock(p, piLeaf?*piLeaf:*piLeaf2, &zBlob, &nBlob, 0);
+    }
+    if( rc==SQLITE_OK ){
+      int iNewHeight = 0;
+      fts3GetVarint32(zBlob, &iNewHeight);
+      if( iNewHeight>=iHeight ){
+        rc = FTS_CORRUPT_VTAB;
+      }else{
+        rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, piLeaf2);
+      }
+    }
+    sqlite3_free(zBlob);
+  }
+
+  return rc;
+}
+
+/*
+** This function is used to create delta-encoded serialized lists of FTS3
+** varints. Each call to this function appends a single varint to a list.
+*/
+static void fts3PutDeltaVarint(
+  char **pp,                      /* IN/OUT: Output pointer */
+  sqlite3_int64 *piPrev,          /* IN/OUT: Previous value written to list */
+  sqlite3_int64 iVal              /* Write this value to the list */
+){
+  assert_fts3_nc( iVal-*piPrev > 0 || (*piPrev==0 && iVal==0) );
+  *pp += sqlite3Fts3PutVarint(*pp, iVal-*piPrev);
+  *piPrev = iVal;
+}
+
+/*
+** When this function is called, *ppPoslist is assumed to point to the
+** start of a position-list. After it returns, *ppPoslist points to the
+** first byte after the position-list.
+**
+** A position list is list of positions (delta encoded) and columns for
+** a single document record of a doclist.  So, in other words, this
+** routine advances *ppPoslist so that it points to the next docid in
+** the doclist, or to the first byte past the end of the doclist.
+**
+** If pp is not NULL, then the contents of the position list are copied
+** to *pp. *pp is set to point to the first byte past the last byte copied
+** before this function returns.
+*/
+static void fts3PoslistCopy(char **pp, char **ppPoslist){
+  char *pEnd = *ppPoslist;
+  char c = 0;
+
+  /* The end of a position list is marked by a zero encoded as an FTS3
+  ** varint. A single POS_END (0) byte. Except, if the 0 byte is preceded by
+  ** a byte with the 0x80 bit set, then it is not a varint 0, but the tail
+  ** of some other, multi-byte, value.
+  **
+  ** The following while-loop moves pEnd to point to the first byte that is not
+  ** immediately preceded by a byte with the 0x80 bit set. Then increments
+  ** pEnd once more so that it points to the byte immediately following the
+  ** last byte in the position-list.
+  */
+  while( *pEnd | c ){
+    c = *pEnd++ & 0x80;
+    testcase( c!=0 && (*pEnd)==0 );
+  }
+  pEnd++;  /* Advance past the POS_END terminator byte */
+
+  if( pp ){
+    int n = (int)(pEnd - *ppPoslist);
+    char *p = *pp;
+    memcpy(p, *ppPoslist, n);
+    p += n;
+    *pp = p;
+  }
+  *ppPoslist = pEnd;
+}
+
+/*
+** When this function is called, *ppPoslist is assumed to point to the
+** start of a column-list. After it returns, *ppPoslist points to the
+** to the terminator (POS_COLUMN or POS_END) byte of the column-list.
+**
+** A column-list is list of delta-encoded positions for a single column
+** within a single document within a doclist.
+**
+** The column-list is terminated either by a POS_COLUMN varint (1) or
+** a POS_END varint (0).  This routine leaves *ppPoslist pointing to
+** the POS_COLUMN or POS_END that terminates the column-list.
+**
+** If pp is not NULL, then the contents of the column-list are copied
+** to *pp. *pp is set to point to the first byte past the last byte copied
+** before this function returns.  The POS_COLUMN or POS_END terminator
+** is not copied into *pp.
+*/
+static void fts3ColumnlistCopy(char **pp, char **ppPoslist){
+  char *pEnd = *ppPoslist;
+  char c = 0;
+
+  /* A column-list is terminated by either a 0x01 or 0x00 byte that is
+  ** not part of a multi-byte varint.
+  */
+  while( 0xFE & (*pEnd | c) ){
+    c = *pEnd++ & 0x80;
+    testcase( c!=0 && ((*pEnd)&0xfe)==0 );
+  }
+  if( pp ){
+    int n = (int)(pEnd - *ppPoslist);
+    char *p = *pp;
+    memcpy(p, *ppPoslist, n);
+    p += n;
+    *pp = p;
+  }
+  *ppPoslist = pEnd;
+}
+
+/*
+** Value used to signify the end of an position-list. This must be
+** as large or larger than any value that might appear on the
+** position-list, even a position list that has been corrupted.
+*/
+#define POSITION_LIST_END LARGEST_INT64
+
+/*
+** This function is used to help parse position-lists. When this function is
+** called, *pp may point to the start of the next varint in the position-list
+** being parsed, or it may point to 1 byte past the end of the position-list
+** (in which case **pp will be a terminator bytes POS_END (0) or
+** (1)).
+**
+** If *pp points past the end of the current position-list, set *pi to
+** POSITION_LIST_END and return. Otherwise, read the next varint from *pp,
+** increment the current value of *pi by the value read, and set *pp to
+** point to the next value before returning.
+**
+** Before calling this routine *pi must be initialized to the value of
+** the previous position, or zero if we are reading the first position
+** in the position-list.  Because positions are delta-encoded, the value
+** of the previous position is needed in order to compute the value of
+** the next position.
+*/
+static void fts3ReadNextPos(
+  char **pp,                    /* IN/OUT: Pointer into position-list buffer */
+  sqlite3_int64 *pi             /* IN/OUT: Value read from position-list */
+){
+  if( (**pp)&0xFE ){
+    int iVal;
+    *pp += fts3GetVarint32((*pp), &iVal);
+    *pi += iVal;
+    *pi -= 2;
+  }else{
+    *pi = POSITION_LIST_END;
+  }
+}
+
+/*
+** If parameter iCol is not 0, write an POS_COLUMN (1) byte followed by
+** the value of iCol encoded as a varint to *pp.   This will start a new
+** column list.
+**
+** Set *pp to point to the byte just after the last byte written before
+** returning (do not modify it if iCol==0). Return the total number of bytes
+** written (0 if iCol==0).
+*/
+static int fts3PutColNumber(char **pp, int iCol){
+  int n = 0;                      /* Number of bytes written */
+  if( iCol ){
+    char *p = *pp;                /* Output pointer */
+    n = 1 + sqlite3Fts3PutVarint(&p[1], iCol);
+    *p = 0x01;
+    *pp = &p[n];
+  }
+  return n;
+}
+
+/*
+** Compute the union of two position lists.  The output written
+** into *pp contains all positions of both *pp1 and *pp2 in sorted
+** order and with any duplicates removed.  All pointers are
+** updated appropriately.   The caller is responsible for insuring
+** that there is enough space in *pp to hold the complete output.
+*/
+static int fts3PoslistMerge(
+  char **pp,                      /* Output buffer */
+  char **pp1,                     /* Left input list */
+  char **pp2                      /* Right input list */
+){
+  char *p = *pp;
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+
+  while( *p1 || *p2 ){
+    int iCol1;         /* The current column index in pp1 */
+    int iCol2;         /* The current column index in pp2 */
+
+    if( *p1==POS_COLUMN ){
+      fts3GetVarint32(&p1[1], &iCol1);
+      if( iCol1==0 ) return FTS_CORRUPT_VTAB;
+    }
+    else if( *p1==POS_END ) iCol1 = 0x7fffffff;
+    else iCol1 = 0;
+
+    if( *p2==POS_COLUMN ){
+      fts3GetVarint32(&p2[1], &iCol2);
+      if( iCol2==0 ) return FTS_CORRUPT_VTAB;
+    }
+    else if( *p2==POS_END ) iCol2 = 0x7fffffff;
+    else iCol2 = 0;
+
+    if( iCol1==iCol2 ){
+      sqlite3_int64 i1 = 0;       /* Last position from pp1 */
+      sqlite3_int64 i2 = 0;       /* Last position from pp2 */
+      sqlite3_int64 iPrev = 0;
+      int n = fts3PutColNumber(&p, iCol1);
+      p1 += n;
+      p2 += n;
+
+      /* At this point, both p1 and p2 point to the start of column-lists
+      ** for the same column (the column with index iCol1 and iCol2).
+      ** A column-list is a list of non-negative delta-encoded varints, each
+      ** incremented by 2 before being stored. Each list is terminated by a
+      ** POS_END (0) or POS_COLUMN (1). The following block merges the two lists
+      ** and writes the results to buffer p. p is left pointing to the byte
+      ** after the list written. No terminator (POS_END or POS_COLUMN) is
+      ** written to the output.
+      */
+      fts3GetDeltaVarint(&p1, &i1);
+      fts3GetDeltaVarint(&p2, &i2);
+      if( i1<2 || i2<2 ){
+        break;
+      }
+      do {
+        fts3PutDeltaVarint(&p, &iPrev, (i1<i2) ? i1 : i2);
+        iPrev -= 2;
+        if( i1==i2 ){
+          fts3ReadNextPos(&p1, &i1);
+          fts3ReadNextPos(&p2, &i2);
+        }else if( i1<i2 ){
+          fts3ReadNextPos(&p1, &i1);
+        }else{
+          fts3ReadNextPos(&p2, &i2);
+        }
+      }while( i1!=POSITION_LIST_END || i2!=POSITION_LIST_END );
+    }else if( iCol1<iCol2 ){
+      p1 += fts3PutColNumber(&p, iCol1);
+      fts3ColumnlistCopy(&p, &p1);
+    }else{
+      p2 += fts3PutColNumber(&p, iCol2);
+      fts3ColumnlistCopy(&p, &p2);
+    }
+  }
+
+  *p++ = POS_END;
+  *pp = p;
+  *pp1 = p1 + 1;
+  *pp2 = p2 + 1;
+  return SQLITE_OK;
+}
+
+/*
+** This function is used to merge two position lists into one. When it is
+** called, *pp1 and *pp2 must both point to position lists. A position-list is
+** the part of a doclist that follows each document id. For example, if a row
+** contains:
+**
+**     'a b c'|'x y z'|'a b b a'
+**
+** Then the position list for this row for token 'b' would consist of:
+**
+**     0x02 0x01 0x02 0x03 0x03 0x00
+**
+** When this function returns, both *pp1 and *pp2 are left pointing to the
+** byte following the 0x00 terminator of their respective position lists.
+**
+** If isSaveLeft is 0, an entry is added to the output position list for
+** each position in *pp2 for which there exists one or more positions in
+** *pp1 so that (pos(*pp2)>pos(*pp1) && pos(*pp2)-pos(*pp1)<=nToken). i.e.
+** when the *pp1 token appears before the *pp2 token, but not more than nToken
+** slots before it.
+**
+** e.g. nToken==1 searches for adjacent positions.
+*/
+static int fts3PoslistPhraseMerge(
+  char **pp,                      /* IN/OUT: Preallocated output buffer */
+  int nToken,                     /* Maximum difference in token positions */
+  int isSaveLeft,                 /* Save the left position */
+  int isExact,                    /* If *pp1 is exactly nTokens before *pp2 */
+  char **pp1,                     /* IN/OUT: Left input list */
+  char **pp2                      /* IN/OUT: Right input list */
+){
+  char *p = *pp;
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+  int iCol1 = 0;
+  int iCol2 = 0;
+
+  /* Never set both isSaveLeft and isExact for the same invocation. */
+  assert( isSaveLeft==0 || isExact==0 );
+
+  assert_fts3_nc( p!=0 && *p1!=0 && *p2!=0 );
+  if( *p1==POS_COLUMN ){
+    p1++;
+    p1 += fts3GetVarint32(p1, &iCol1);
+    /* iCol1==0 indicates corruption. Column 0 does not have a POS_COLUMN
+    ** entry, so this is actually end-of-doclist. */
+    if( iCol1==0 ) return 0;
+  }
+  if( *p2==POS_COLUMN ){
+    p2++;
+    p2 += fts3GetVarint32(p2, &iCol2);
+    /* As above, iCol2==0 indicates corruption. */
+    if( iCol2==0 ) return 0;
+  }
+
+  while( 1 ){
+    if( iCol1==iCol2 ){
+      char *pSave = p;
+      sqlite3_int64 iPrev = 0;
+      sqlite3_int64 iPos1 = 0;
+      sqlite3_int64 iPos2 = 0;
+
+      if( iCol1 ){
+        *p++ = POS_COLUMN;
+        p += sqlite3Fts3PutVarint(p, iCol1);
+      }
+
+      fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
+      fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
+      if( iPos1<0 || iPos2<0 ) break;
+
+      while( 1 ){
+        if( iPos2==iPos1+nToken
+         || (isExact==0 && iPos2>iPos1 && iPos2<=iPos1+nToken)
+        ){
+          sqlite3_int64 iSave;
+          iSave = isSaveLeft ? iPos1 : iPos2;
+          fts3PutDeltaVarint(&p, &iPrev, iSave+2); iPrev -= 2;
+          pSave = 0;
+          assert( p );
+        }
+        if( (!isSaveLeft && iPos2<=(iPos1+nToken)) || iPos2<=iPos1 ){
+          if( (*p2&0xFE)==0 ) break;
+          fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2;
+        }else{
+          if( (*p1&0xFE)==0 ) break;
+          fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2;
+        }
+      }
+
+      if( pSave ){
+        assert( pp && p );
+        p = pSave;
+      }
+
+      fts3ColumnlistCopy(0, &p1);
+      fts3ColumnlistCopy(0, &p2);
+      assert( (*p1&0xFE)==0 && (*p2&0xFE)==0 );
+      if( 0==*p1 || 0==*p2 ) break;
+
+      p1++;
+      p1 += fts3GetVarint32(p1, &iCol1);
+      p2++;
+      p2 += fts3GetVarint32(p2, &iCol2);
+    }
+
+    /* Advance pointer p1 or p2 (whichever corresponds to the smaller of
+    ** iCol1 and iCol2) so that it points to either the 0x00 that marks the
+    ** end of the position list, or the 0x01 that precedes the next
+    ** column-number in the position list.
+    */
+    else if( iCol1<iCol2 ){
+      fts3ColumnlistCopy(0, &p1);
+      if( 0==*p1 ) break;
+      p1++;
+      p1 += fts3GetVarint32(p1, &iCol1);
+    }else{
+      fts3ColumnlistCopy(0, &p2);
+      if( 0==*p2 ) break;
+      p2++;
+      p2 += fts3GetVarint32(p2, &iCol2);
+    }
+  }
+
+  fts3PoslistCopy(0, &p2);
+  fts3PoslistCopy(0, &p1);
+  *pp1 = p1;
+  *pp2 = p2;
+  if( *pp==p ){
+    return 0;
+  }
+  *p++ = 0x00;
+  *pp = p;
+  return 1;
+}
+
+/*
+** Merge two position-lists as required by the NEAR operator. The argument
+** position lists correspond to the left and right phrases of an expression
+** like:
+**
+**     "phrase 1" NEAR "phrase number 2"
+**
+** Position list *pp1 corresponds to the left-hand side of the NEAR
+** expression and *pp2 to the right. As usual, the indexes in the position
+** lists are the offsets of the last token in each phrase (tokens "1" and "2"
+** in the example above).
+**
+** The output position list - written to *pp - is a copy of *pp2 with those
+** entries that are not sufficiently NEAR entries in *pp1 removed.
+*/
+static int fts3PoslistNearMerge(
+  char **pp,                      /* Output buffer */
+  char *aTmp,                     /* Temporary buffer space */
+  int nRight,                     /* Maximum difference in token positions */
+  int nLeft,                      /* Maximum difference in token positions */
+  char **pp1,                     /* IN/OUT: Left input list */
+  char **pp2                      /* IN/OUT: Right input list */
+){
+  char *p1 = *pp1;
+  char *p2 = *pp2;
+
+  char *pTmp1 = aTmp;
+  char *pTmp2;
+  char *aTmp2;
+  int res = 1;
+
+  fts3PoslistPhraseMerge(&pTmp1, nRight, 0, 0, pp1, pp2);
+  aTmp2 = pTmp2 = pTmp1;
+  *pp1 = p1;
+  *pp2 = p2;
+  fts3PoslistPhraseMerge(&pTmp2, nLeft, 1, 0, pp2, pp1);
+  if( pTmp1!=aTmp && pTmp2!=aTmp2 ){
+    fts3PoslistMerge(pp, &aTmp, &aTmp2);
+  }else if( pTmp1!=aTmp ){
+    fts3PoslistCopy(pp, &aTmp);
+  }else if( pTmp2!=aTmp2 ){
+    fts3PoslistCopy(pp, &aTmp2);
+  }else{
+    res = 0;
+  }
+
+  return res;
+}
+
+/*
+** An instance of this function is used to merge together the (potentially
+** large number of) doclists for each term that matches a prefix query.
+** See function fts3TermSelectMerge() for details.
+*/
+typedef struct TermSelect TermSelect;
+struct TermSelect {
+  char *aaOutput[16];             /* Malloc'd output buffers */
+  int anOutput[16];               /* Size each output buffer in bytes */
+};
+
+/*
+** This function is used to read a single varint from a buffer. Parameter
+** pEnd points 1 byte past the end of the buffer. When this function is
+** called, if *pp points to pEnd or greater, then the end of the buffer
+** has been reached. In this case *pp is set to 0 and the function returns.
+**
+** If *pp does not point to or past pEnd, then a single varint is read
+** from *pp. *pp is then set to point 1 byte past the end of the read varint.
+**
+** If bDescIdx is false, the value read is added to *pVal before returning.
+** If it is true, the value read is subtracted from *pVal before this
+** function returns.
+*/
+static void fts3GetDeltaVarint3(
+  char **pp,                      /* IN/OUT: Point to read varint from */
+  char *pEnd,                     /* End of buffer */
+  int bDescIdx,                   /* True if docids are descending */
+  sqlite3_int64 *pVal             /* IN/OUT: Integer value */
+){
+  if( *pp>=pEnd ){
+    *pp = 0;
+  }else{
+    u64 iVal;
+    *pp += sqlite3Fts3GetVarintU(*pp, &iVal);
+    if( bDescIdx ){
+      *pVal = (i64)((u64)*pVal - iVal);
+    }else{
+      *pVal = (i64)((u64)*pVal + iVal);
+    }
+  }
+}
+
+/*
+** This function is used to write a single varint to a buffer. The varint
+** is written to *pp. Before returning, *pp is set to point 1 byte past the
+** end of the value written.
+**
+** If *pbFirst is zero when this function is called, the value written to
+** the buffer is that of parameter iVal.
+**
+** If *pbFirst is non-zero when this function is called, then the value
+** written is either (iVal-*piPrev) (if bDescIdx is zero) or (*piPrev-iVal)
+** (if bDescIdx is non-zero).
+**
+** Before returning, this function always sets *pbFirst to 1 and *piPrev
+** to the value of parameter iVal.
+*/
+static void fts3PutDeltaVarint3(
+  char **pp,                      /* IN/OUT: Output pointer */
+  int bDescIdx,                   /* True for descending docids */
+  sqlite3_int64 *piPrev,          /* IN/OUT: Previous value written to list */
+  int *pbFirst,                   /* IN/OUT: True after first int written */
+  sqlite3_int64 iVal              /* Write this value to the list */
+){
+  sqlite3_uint64 iWrite;
+  if( bDescIdx==0 || *pbFirst==0 ){
+    assert_fts3_nc( *pbFirst==0 || iVal>=*piPrev );
+    iWrite = (u64)iVal - (u64)*piPrev;
+  }else{
+    assert_fts3_nc( *piPrev>=iVal );
+    iWrite = (u64)*piPrev - (u64)iVal;
+  }
+  assert( *pbFirst || *piPrev==0 );
+  assert_fts3_nc( *pbFirst==0 || iWrite>0 );
+  *pp += sqlite3Fts3PutVarint(*pp, iWrite);
+  *piPrev = iVal;
+  *pbFirst = 1;
+}
+
+
+/*
+** This macro is used by various functions that merge doclists. The two
+** arguments are 64-bit docid values. If the value of the stack variable
+** bDescDoclist is 0 when this macro is invoked, then it returns (i1-i2).
+** Otherwise, (i2-i1).
+**
+** Using this makes it easier to write code that can merge doclists that are
+** sorted in either ascending or descending order.
+*/
+/* #define DOCID_CMP(i1, i2) ((bDescDoclist?-1:1) * (i64)((u64)i1-i2)) */
+#define DOCID_CMP(i1, i2) ((bDescDoclist?-1:1) * (i1>i2?1:((i1==i2)?0:-1)))
+
+/*
+** This function does an "OR" merge of two doclists (output contains all
+** positions contained in either argument doclist). If the docids in the
+** input doclists are sorted in ascending order, parameter bDescDoclist
+** should be false. If they are sorted in ascending order, it should be
+** passed a non-zero value.
+**
+** If no error occurs, *paOut is set to point at an sqlite3_malloc'd buffer
+** containing the output doclist and SQLITE_OK is returned. In this case
+** *pnOut is set to the number of bytes in the output doclist.
+**
+** If an error occurs, an SQLite error code is returned. The output values
+** are undefined in this case.
+*/
+static int fts3DoclistOrMerge(
+  int bDescDoclist,               /* True if arguments are desc */
+  char *a1, int n1,               /* First doclist */
+  char *a2, int n2,               /* Second doclist */
+  char **paOut, int *pnOut        /* OUT: Malloc'd doclist */
+){
+  int rc = SQLITE_OK;
+  sqlite3_int64 i1 = 0;
+  sqlite3_int64 i2 = 0;
+  sqlite3_int64 iPrev = 0;
+  char *pEnd1 = &a1[n1];
+  char *pEnd2 = &a2[n2];
+  char *p1 = a1;
+  char *p2 = a2;
+  char *p;
+  char *aOut;
+  int bFirstOut = 0;
+
+  *paOut = 0;
+  *pnOut = 0;
+
+  /* Allocate space for the output. Both the input and output doclists
+  ** are delta encoded. If they are in ascending order (bDescDoclist==0),
+  ** then the first docid in each list is simply encoded as a varint. For
+  ** each subsequent docid, the varint stored is the difference between the
+  ** current and previous docid (a positive number - since the list is in
+  ** ascending order).
+  **
+  ** The first docid written to the output is therefore encoded using the
+  ** same number of bytes as it is in whichever of the input lists it is
+  ** read from. And each subsequent docid read from the same input list
+  ** consumes either the same or less bytes as it did in the input (since
+  ** the difference between it and the previous value in the output must
+  ** be a positive value less than or equal to the delta value read from
+  ** the input list). The same argument applies to all but the first docid
+  ** read from the 'other' list. And to the contents of all position lists
+  ** that will be copied and merged from the input to the output.
+  **
+  ** However, if the first docid copied to the output is a negative number,
+  ** then the encoding of the first docid from the 'other' input list may
+  ** be larger in the output than it was in the input (since the delta value
+  ** may be a larger positive integer than the actual docid).
+  **
+  ** The space required to store the output is therefore the sum of the
+  ** sizes of the two inputs, plus enough space for exactly one of the input
+  ** docids to grow.
+  **
+  ** A symetric argument may be made if the doclists are in descending
+  ** order.
+  */
+  aOut = sqlite3_malloc64((i64)n1+n2+FTS3_VARINT_MAX-1+FTS3_BUFFER_PADDING);
+  if( !aOut ) return SQLITE_NOMEM;
+
+  p = aOut;
+  fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1);
+  fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2);
+  while( p1 || p2 ){
+    sqlite3_int64 iDiff = DOCID_CMP(i1, i2);
+
+    if( p2 && p1 && iDiff==0 ){
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1);
+      rc = fts3PoslistMerge(&p, &p1, &p2);
+      if( rc ) break;
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }else if( !p2 || (p1 && iDiff<0) ){
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1);
+      fts3PoslistCopy(&p, &p1);
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+    }else{
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i2);
+      fts3PoslistCopy(&p, &p2);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }
+
+    assert( (p-aOut)<=((p1?(p1-a1):n1)+(p2?(p2-a2):n2)+FTS3_VARINT_MAX-1) );
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(aOut);
+    p = aOut = 0;
+  }else{
+    assert( (p-aOut)<=n1+n2+FTS3_VARINT_MAX-1 );
+    memset(&aOut[(p-aOut)], 0, FTS3_BUFFER_PADDING);
+  }
+  *paOut = aOut;
+  *pnOut = (int)(p-aOut);
+  return rc;
+}
+
+/*
+** This function does a "phrase" merge of two doclists. In a phrase merge,
+** the output contains a copy of each position from the right-hand input
+** doclist for which there is a position in the left-hand input doclist
+** exactly nDist tokens before it.
+**
+** If the docids in the input doclists are sorted in ascending order,
+** parameter bDescDoclist should be false. If they are sorted in ascending
+** order, it should be passed a non-zero value.
+**
+** The right-hand input doclist is overwritten by this function.
+*/
+static int fts3DoclistPhraseMerge(
+  int bDescDoclist,               /* True if arguments are desc */
+  int nDist,                      /* Distance from left to right (1=adjacent) */
+  char *aLeft, int nLeft,         /* Left doclist */
+  char **paRight, int *pnRight    /* IN/OUT: Right/output doclist */
+){
+  sqlite3_int64 i1 = 0;
+  sqlite3_int64 i2 = 0;
+  sqlite3_int64 iPrev = 0;
+  char *aRight = *paRight;
+  char *pEnd1 = &aLeft[nLeft];
+  char *pEnd2 = &aRight[*pnRight];
+  char *p1 = aLeft;
+  char *p2 = aRight;
+  char *p;
+  int bFirstOut = 0;
+  char *aOut;
+
+  assert( nDist>0 );
+  if( bDescDoclist ){
+    aOut = sqlite3_malloc64((sqlite3_int64)*pnRight + FTS3_VARINT_MAX);
+    if( aOut==0 ) return SQLITE_NOMEM;
+  }else{
+    aOut = aRight;
+  }
+  p = aOut;
+
+  fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1);
+  fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2);
+
+  while( p1 && p2 ){
+    sqlite3_int64 iDiff = DOCID_CMP(i1, i2);
+    if( iDiff==0 ){
+      char *pSave = p;
+      sqlite3_int64 iPrevSave = iPrev;
+      int bFirstOutSave = bFirstOut;
+
+      fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1);
+      if( 0==fts3PoslistPhraseMerge(&p, nDist, 0, 1, &p1, &p2) ){
+        p = pSave;
+        iPrev = iPrevSave;
+        bFirstOut = bFirstOutSave;
+      }
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }else if( iDiff<0 ){
+      fts3PoslistCopy(0, &p1);
+      fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1);
+    }else{
+      fts3PoslistCopy(0, &p2);
+      fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2);
+    }
+  }
+
+  *pnRight = (int)(p - aOut);
+  if( bDescDoclist ){
+    sqlite3_free(aRight);
+    *paRight = aOut;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Argument pList points to a position list nList bytes in size. This
+** function checks to see if the position list contains any entries for
+** a token in position 0 (of any column). If so, it writes argument iDelta
+** to the output buffer pOut, followed by a position list consisting only
+** of the entries from pList at position 0, and terminated by an 0x00 byte.
+** The value returned is the number of bytes written to pOut (if any).
+*/
+SQLITE_PRIVATE int sqlite3Fts3FirstFilter(
+  sqlite3_int64 iDelta,           /* Varint that may be written to pOut */
+  char *pList,                    /* Position list (no 0x00 term) */
+  int nList,                      /* Size of pList in bytes */
+  char *pOut                      /* Write output here */
+){
+  int nOut = 0;
+  int bWritten = 0;               /* True once iDelta has been written */
+  char *p = pList;
+  char *pEnd = &pList[nList];
+
+  if( *p!=0x01 ){
+    if( *p==0x02 ){
+      nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta);
+      pOut[nOut++] = 0x02;
+      bWritten = 1;
+    }
+    fts3ColumnlistCopy(0, &p);
+  }
+
+  while( p<pEnd ){
+    sqlite3_int64 iCol;
+    p++;
+    p += sqlite3Fts3GetVarint(p, &iCol);
+    if( *p==0x02 ){
+      if( bWritten==0 ){
+        nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta);
+        bWritten = 1;
+      }
+      pOut[nOut++] = 0x01;
+      nOut += sqlite3Fts3PutVarint(&pOut[nOut], iCol);
+      pOut[nOut++] = 0x02;
+    }
+    fts3ColumnlistCopy(0, &p);
+  }
+  if( bWritten ){
+    pOut[nOut++] = 0x00;
+  }
+
+  return nOut;
+}
+
+
+/*
+** Merge all doclists in the TermSelect.aaOutput[] array into a single
+** doclist stored in TermSelect.aaOutput[0]. If successful, delete all
+** other doclists (except the aaOutput[0] one) and return SQLITE_OK.
+**
+** If an OOM error occurs, return SQLITE_NOMEM. In this case it is
+** the responsibility of the caller to free any doclists left in the
+** TermSelect.aaOutput[] array.
+*/
+static int fts3TermSelectFinishMerge(Fts3Table *p, TermSelect *pTS){
+  char *aOut = 0;
+  int nOut = 0;
+  int i;
+
+  /* Loop through the doclists in the aaOutput[] array. Merge them all
+  ** into a single doclist.
+  */
+  for(i=0; i<SizeofArray(pTS->aaOutput); i++){
+    if( pTS->aaOutput[i] ){
+      if( !aOut ){
+        aOut = pTS->aaOutput[i];
+        nOut = pTS->anOutput[i];
+        pTS->aaOutput[i] = 0;
+      }else{
+        int nNew;
+        char *aNew;
+
+        int rc = fts3DoclistOrMerge(p->bDescIdx,
+            pTS->aaOutput[i], pTS->anOutput[i], aOut, nOut, &aNew, &nNew
+        );
+        if( rc!=SQLITE_OK ){
+          sqlite3_free(aOut);
+          return rc;
+        }
+
+        sqlite3_free(pTS->aaOutput[i]);
+        sqlite3_free(aOut);
+        pTS->aaOutput[i] = 0;
+        aOut = aNew;
+        nOut = nNew;
+      }
+    }
+  }
+
+  pTS->aaOutput[0] = aOut;
+  pTS->anOutput[0] = nOut;
+  return SQLITE_OK;
+}
+
+/*
+** Merge the doclist aDoclist/nDoclist into the TermSelect object passed
+** as the first argument. The merge is an "OR" merge (see function
+** fts3DoclistOrMerge() for details).
+**
+** This function is called with the doclist for each term that matches
+** a queried prefix. It merges all these doclists into one, the doclist
+** for the specified prefix. Since there can be a very large number of
+** doclists to merge, the merging is done pair-wise using the TermSelect
+** object.
+**
+** This function returns SQLITE_OK if the merge is successful, or an
+** SQLite error code (SQLITE_NOMEM) if an error occurs.
+*/
+static int fts3TermSelectMerge(
+  Fts3Table *p,                   /* FTS table handle */
+  TermSelect *pTS,                /* TermSelect object to merge into */
+  char *aDoclist,                 /* Pointer to doclist */
+  int nDoclist                    /* Size of aDoclist in bytes */
+){
+  if( pTS->aaOutput[0]==0 ){
+    /* If this is the first term selected, copy the doclist to the output
+    ** buffer using memcpy().
+    **
+    ** Add FTS3_VARINT_MAX bytes of unused space to the end of the
+    ** allocation. This is so as to ensure that the buffer is big enough
+    ** to hold the current doclist AND'd with any other doclist. If the
+    ** doclists are stored in order=ASC order, this padding would not be
+    ** required (since the size of [doclistA AND doclistB] is always less
+    ** than or equal to the size of [doclistA] in that case). But this is
+    ** not true for order=DESC. For example, a doclist containing (1, -1)
+    ** may be smaller than (-1), as in the first example the -1 may be stored
+    ** as a single-byte delta, whereas in the second it must be stored as a
+    ** FTS3_VARINT_MAX byte varint.
+    **
+    ** Similar padding is added in the fts3DoclistOrMerge() function.
+    */
+    pTS->aaOutput[0] = sqlite3_malloc64((i64)nDoclist + FTS3_VARINT_MAX + 1);
+    pTS->anOutput[0] = nDoclist;
+    if( pTS->aaOutput[0] ){
+      memcpy(pTS->aaOutput[0], aDoclist, nDoclist);
+      memset(&pTS->aaOutput[0][nDoclist], 0, FTS3_VARINT_MAX);
+    }else{
+      return SQLITE_NOMEM;
+    }
+  }else{
+    char *aMerge = aDoclist;
+    int nMerge = nDoclist;
+    int iOut;
+
+    for(iOut=0; iOut<SizeofArray(pTS->aaOutput); iOut++){
+      if( pTS->aaOutput[iOut]==0 ){
+        assert( iOut>0 );
+        pTS->aaOutput[iOut] = aMerge;
+        pTS->anOutput[iOut] = nMerge;
+        break;
+      }else{
+        char *aNew;
+        int nNew;
+
+        int rc = fts3DoclistOrMerge(p->bDescIdx, aMerge, nMerge,
+            pTS->aaOutput[iOut], pTS->anOutput[iOut], &aNew, &nNew
+        );
+        if( rc!=SQLITE_OK ){
+          if( aMerge!=aDoclist ) sqlite3_free(aMerge);
+          return rc;
+        }
+
+        if( aMerge!=aDoclist ) sqlite3_free(aMerge);
+        sqlite3_free(pTS->aaOutput[iOut]);
+        pTS->aaOutput[iOut] = 0;
+
+        aMerge = aNew;
+        nMerge = nNew;
+        if( (iOut+1)==SizeofArray(pTS->aaOutput) ){
+          pTS->aaOutput[iOut] = aMerge;
+          pTS->anOutput[iOut] = nMerge;
+        }
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Append SegReader object pNew to the end of the pCsr->apSegment[] array.
+*/
+static int fts3SegReaderCursorAppend(
+  Fts3MultiSegReader *pCsr,
+  Fts3SegReader *pNew
+){
+  if( (pCsr->nSegment%16)==0 ){
+    Fts3SegReader **apNew;
+    sqlite3_int64 nByte = (pCsr->nSegment + 16)*sizeof(Fts3SegReader*);
+    apNew = (Fts3SegReader **)sqlite3_realloc64(pCsr->apSegment, nByte);
+    if( !apNew ){
+      sqlite3Fts3SegReaderFree(pNew);
+      return SQLITE_NOMEM;
+    }
+    pCsr->apSegment = apNew;
+  }
+  pCsr->apSegment[pCsr->nSegment++] = pNew;
+  return SQLITE_OK;
+}
+
+/*
+** Add seg-reader objects to the Fts3MultiSegReader object passed as the
+** 8th argument.
+**
+** This function returns SQLITE_OK if successful, or an SQLite error code
+** otherwise.
+*/
+static int fts3SegReaderCursor(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index to search (from 0 to p->nIndex-1) */
+  int iLevel,                     /* Level of segments to scan */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  int isScan,                     /* True to scan from zTerm to EOF */
+  Fts3MultiSegReader *pCsr        /* Cursor object to populate */
+){
+  int rc = SQLITE_OK;             /* Error code */
+  sqlite3_stmt *pStmt = 0;        /* Statement to iterate through segments */
+  int rc2;                        /* Result of sqlite3_reset() */
+
+  /* If iLevel is less than 0 and this is not a scan, include a seg-reader
+  ** for the pending-terms. If this is a scan, then this call must be being
+  ** made by an fts4aux module, not an FTS table. In this case calling
+  ** Fts3SegReaderPending might segfault, as the data structures used by
+  ** fts4aux are not completely populated. So it's easiest to filter these
+  ** calls out here.  */
+  if( iLevel<0 && p->aIndex && p->iPrevLangid==iLangid ){
+    Fts3SegReader *pSeg = 0;
+    rc = sqlite3Fts3SegReaderPending(p, iIndex, zTerm, nTerm, isPrefix||isScan, &pSeg);
+    if( rc==SQLITE_OK && pSeg ){
+      rc = fts3SegReaderCursorAppend(pCsr, pSeg);
+    }
+  }
+
+  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts3AllSegdirs(p, iLangid, iIndex, iLevel, &pStmt);
+    }
+
+    while( rc==SQLITE_OK && SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
+      Fts3SegReader *pSeg = 0;
+
+      /* Read the values returned by the SELECT into local variables. */
+      sqlite3_int64 iStartBlock = sqlite3_column_int64(pStmt, 1);
+      sqlite3_int64 iLeavesEndBlock = sqlite3_column_int64(pStmt, 2);
+      sqlite3_int64 iEndBlock = sqlite3_column_int64(pStmt, 3);
+      int nRoot = sqlite3_column_bytes(pStmt, 4);
+      char const *zRoot = sqlite3_column_blob(pStmt, 4);
+
+      /* If zTerm is not NULL, and this segment is not stored entirely on its
+      ** root node, the range of leaves scanned can be reduced. Do this. */
+      if( iStartBlock && zTerm && zRoot ){
+        sqlite3_int64 *pi = (isPrefix ? &iLeavesEndBlock : 0);
+        rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &iStartBlock, pi);
+        if( rc!=SQLITE_OK ) goto finished;
+        if( isPrefix==0 && isScan==0 ) iLeavesEndBlock = iStartBlock;
+      }
+
+      rc = sqlite3Fts3SegReaderNew(pCsr->nSegment+1,
+          (isPrefix==0 && isScan==0),
+          iStartBlock, iLeavesEndBlock,
+          iEndBlock, zRoot, nRoot, &pSeg
+      );
+      if( rc!=SQLITE_OK ) goto finished;
+      rc = fts3SegReaderCursorAppend(pCsr, pSeg);
+    }
+  }
+
+ finished:
+  rc2 = sqlite3_reset(pStmt);
+  if( rc==SQLITE_DONE ) rc = rc2;
+
+  return rc;
+}
+
+/*
+** Set up a cursor object for iterating through a full-text index or a
+** single level therein.
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderCursor(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language-id to search */
+  int iIndex,                     /* Index to search (from 0 to p->nIndex-1) */
+  int iLevel,                     /* Level of segments to scan */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  int isScan,                     /* True to scan from zTerm to EOF */
+  Fts3MultiSegReader *pCsr       /* Cursor object to populate */
+){
+  assert( iIndex>=0 && iIndex<p->nIndex );
+  assert( iLevel==FTS3_SEGCURSOR_ALL
+      ||  iLevel==FTS3_SEGCURSOR_PENDING
+      ||  iLevel>=0
+  );
+  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
+  assert( FTS3_SEGCURSOR_ALL<0 && FTS3_SEGCURSOR_PENDING<0 );
+  assert( isPrefix==0 || isScan==0 );
+
+  memset(pCsr, 0, sizeof(Fts3MultiSegReader));
+  return fts3SegReaderCursor(
+      p, iLangid, iIndex, iLevel, zTerm, nTerm, isPrefix, isScan, pCsr
+  );
+}
+
+/*
+** In addition to its current configuration, have the Fts3MultiSegReader
+** passed as the 4th argument also scan the doclist for term zTerm/nTerm.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3SegReaderCursorAddZero(
+  Fts3Table *p,                   /* FTS virtual table handle */
+  int iLangid,
+  const char *zTerm,              /* Term to scan doclist of */
+  int nTerm,                      /* Number of bytes in zTerm */
+  Fts3MultiSegReader *pCsr        /* Fts3MultiSegReader to modify */
+){
+  return fts3SegReaderCursor(p,
+      iLangid, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0,pCsr
+  );
+}
+
+/*
+** Open an Fts3MultiSegReader to scan the doclist for term zTerm/nTerm. Or,
+** if isPrefix is true, to scan the doclist for all terms for which
+** zTerm/nTerm is a prefix. If successful, return SQLITE_OK and write
+** a pointer to the new Fts3MultiSegReader to *ppSegcsr. Otherwise, return
+** an SQLite error code.
+**
+** It is the responsibility of the caller to free this object by eventually
+** passing it to fts3SegReaderCursorFree()
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+** Output parameter *ppSegcsr is set to 0 if an error occurs.
+*/
+static int fts3TermSegReaderCursor(
+  Fts3Cursor *pCsr,               /* Virtual table cursor handle */
+  const char *zTerm,              /* Term to query for */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int isPrefix,                   /* True for a prefix search */
+  Fts3MultiSegReader **ppSegcsr   /* OUT: Allocated seg-reader cursor */
+){
+  Fts3MultiSegReader *pSegcsr;    /* Object to allocate and return */
+  int rc = SQLITE_NOMEM;          /* Return code */
+
+  pSegcsr = sqlite3_malloc(sizeof(Fts3MultiSegReader));
+  if( pSegcsr ){
+    int i;
+    int bFound = 0;               /* True once an index has been found */
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+
+    if( isPrefix ){
+      for(i=1; bFound==0 && i<p->nIndex; i++){
+        if( p->aIndex[i].nPrefix==nTerm ){
+          bFound = 1;
+          rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid,
+              i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0, pSegcsr
+          );
+          pSegcsr->bLookup = 1;
+        }
+      }
+
+      for(i=1; bFound==0 && i<p->nIndex; i++){
+        if( p->aIndex[i].nPrefix==nTerm+1 ){
+          bFound = 1;
+          rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid,
+              i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 1, 0, pSegcsr
+          );
+          if( rc==SQLITE_OK ){
+            rc = fts3SegReaderCursorAddZero(
+                p, pCsr->iLangid, zTerm, nTerm, pSegcsr
+            );
+          }
+        }
+      }
+    }
+
+    if( bFound==0 ){
+      rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid,
+          0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, isPrefix, 0, pSegcsr
+      );
+      pSegcsr->bLookup = !isPrefix;
+    }
+  }
+
+  *ppSegcsr = pSegcsr;
+  return rc;
+}
+
+/*
+** Free an Fts3MultiSegReader allocated by fts3TermSegReaderCursor().
+*/
+static void fts3SegReaderCursorFree(Fts3MultiSegReader *pSegcsr){
+  sqlite3Fts3SegReaderFinish(pSegcsr);
+  sqlite3_free(pSegcsr);
+}
+
+/*
+** This function retrieves the doclist for the specified term (or term
+** prefix) from the database.
+*/
+static int fts3TermSelect(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3PhraseToken *pTok,          /* Token to query for */
+  int iColumn,                    /* Column to query (or -ve for all columns) */
+  int *pnOut,                     /* OUT: Size of buffer at *ppOut */
+  char **ppOut                    /* OUT: Malloced result buffer */
+){
+  int rc;                         /* Return code */
+  Fts3MultiSegReader *pSegcsr;    /* Seg-reader cursor for this term */
+  TermSelect tsc;                 /* Object for pair-wise doclist merging */
+  Fts3SegFilter filter;           /* Segment term filter configuration */
+
+  pSegcsr = pTok->pSegcsr;
+  memset(&tsc, 0, sizeof(TermSelect));
+
+  filter.flags = FTS3_SEGMENT_IGNORE_EMPTY | FTS3_SEGMENT_REQUIRE_POS
+        | (pTok->isPrefix ? FTS3_SEGMENT_PREFIX : 0)
+        | (pTok->bFirst ? FTS3_SEGMENT_FIRST : 0)
+        | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0);
+  filter.iCol = iColumn;
+  filter.zTerm = pTok->z;
+  filter.nTerm = pTok->n;
+
+  rc = sqlite3Fts3SegReaderStart(p, pSegcsr, &filter);
+  while( SQLITE_OK==rc
+      && SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, pSegcsr))
+  ){
+    rc = fts3TermSelectMerge(p, &tsc, pSegcsr->aDoclist, pSegcsr->nDoclist);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts3TermSelectFinishMerge(p, &tsc);
+  }
+  if( rc==SQLITE_OK ){
+    *ppOut = tsc.aaOutput[0];
+    *pnOut = tsc.anOutput[0];
+  }else{
+    int i;
+    for(i=0; i<SizeofArray(tsc.aaOutput); i++){
+      sqlite3_free(tsc.aaOutput[i]);
+    }
+  }
+
+  fts3SegReaderCursorFree(pSegcsr);
+  pTok->pSegcsr = 0;
+  return rc;
+}
+
+/*
+** This function counts the total number of docids in the doclist stored
+** in buffer aList[], size nList bytes.
+**
+** If the isPoslist argument is true, then it is assumed that the doclist
+** contains a position-list following each docid. Otherwise, it is assumed
+** that the doclist is simply a list of docids stored as delta encoded
+** varints.
+*/
+static int fts3DoclistCountDocids(char *aList, int nList){
+  int nDoc = 0;                   /* Return value */
+  if( aList ){
+    char *aEnd = &aList[nList];   /* Pointer to one byte after EOF */
+    char *p = aList;              /* Cursor */
+    while( p<aEnd ){
+      nDoc++;
+      while( (*p++)&0x80 );     /* Skip docid varint */
+      fts3PoslistCopy(0, &p);   /* Skip over position list */
+    }
+  }
+
+  return nDoc;
+}
+
+/*
+** Advance the cursor to the next row in the %_content table that
+** matches the search criteria.  For a MATCH search, this will be
+** the next row that matches. For a full-table scan, this will be
+** simply the next row in the %_content table.  For a docid lookup,
+** this routine simply sets the EOF flag.
+**
+** Return SQLITE_OK if nothing goes wrong.  SQLITE_OK is returned
+** even if we reach end-of-file.  The fts3EofMethod() will be called
+** subsequently to determine whether or not an EOF was hit.
+*/
+static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){
+  int rc;
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+  if( pCsr->eSearch==FTS3_DOCID_SEARCH || pCsr->eSearch==FTS3_FULLSCAN_SEARCH ){
+    Fts3Table *pTab = (Fts3Table*)pCursor->pVtab;
+    pTab->bLock++;
+    if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){
+      pCsr->isEof = 1;
+      rc = sqlite3_reset(pCsr->pStmt);
+    }else{
+      pCsr->iPrevId = sqlite3_column_int64(pCsr->pStmt, 0);
+      rc = SQLITE_OK;
+    }
+    pTab->bLock--;
+  }else{
+    rc = fts3EvalNext((Fts3Cursor *)pCursor);
+  }
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  return rc;
+}
+
+/*
+** If the numeric type of argument pVal is "integer", then return it
+** converted to a 64-bit signed integer. Otherwise, return a copy of
+** the second parameter, iDefault.
+*/
+static sqlite3_int64 fts3DocidRange(sqlite3_value *pVal, i64 iDefault){
+  if( pVal ){
+    int eType = sqlite3_value_numeric_type(pVal);
+    if( eType==SQLITE_INTEGER ){
+      return sqlite3_value_int64(pVal);
+    }
+  }
+  return iDefault;
+}
+
+/*
+** This is the xFilter interface for the virtual table.  See
+** the virtual table xFilter method documentation for additional
+** information.
+**
+** If idxNum==FTS3_FULLSCAN_SEARCH then do a full table scan against
+** the %_content table.
+**
+** If idxNum==FTS3_DOCID_SEARCH then do a docid lookup for a single entry
+** in the %_content table.
+**
+** If idxNum>=FTS3_FULLTEXT_SEARCH then use the full text index.  The
+** column on the left-hand side of the MATCH operator is column
+** number idxNum-FTS3_FULLTEXT_SEARCH, 0 indexed.  argv[0] is the right-hand
+** side of the MATCH operator.
+*/
+static int fts3FilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  int rc = SQLITE_OK;
+  char *zSql;                     /* SQL statement used to access %_content */
+  int eSearch;
+  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
+  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
+
+  sqlite3_value *pCons = 0;       /* The MATCH or rowid constraint, if any */
+  sqlite3_value *pLangid = 0;     /* The "langid = ?" constraint, if any */
+  sqlite3_value *pDocidGe = 0;    /* The "docid >= ?" constraint, if any */
+  sqlite3_value *pDocidLe = 0;    /* The "docid <= ?" constraint, if any */
+  int iIdx;
+
+  UNUSED_PARAMETER(idxStr);
+  UNUSED_PARAMETER(nVal);
+
+  if( p->bLock ){
+    return SQLITE_ERROR;
+  }
+
+  eSearch = (idxNum & 0x0000FFFF);
+  assert( eSearch>=0 && eSearch<=(FTS3_FULLTEXT_SEARCH+p->nColumn) );
+  assert( p->pSegments==0 );
+
+  /* Collect arguments into local variables */
+  iIdx = 0;
+  if( eSearch!=FTS3_FULLSCAN_SEARCH ) pCons = apVal[iIdx++];
+  if( idxNum & FTS3_HAVE_LANGID ) pLangid = apVal[iIdx++];
+  if( idxNum & FTS3_HAVE_DOCID_GE ) pDocidGe = apVal[iIdx++];
+  if( idxNum & FTS3_HAVE_DOCID_LE ) pDocidLe = apVal[iIdx++];
+  assert( iIdx==nVal );
+
+  /* In case the cursor has been used before, clear it now. */
+  fts3ClearCursor(pCsr);
+
+  /* Set the lower and upper bounds on docids to return */
+  pCsr->iMinDocid = fts3DocidRange(pDocidGe, SMALLEST_INT64);
+  pCsr->iMaxDocid = fts3DocidRange(pDocidLe, LARGEST_INT64);
+
+  if( idxStr ){
+    pCsr->bDesc = (idxStr[0]=='D');
+  }else{
+    pCsr->bDesc = p->bDescIdx;
+  }
+  pCsr->eSearch = (i16)eSearch;
+
+  if( eSearch!=FTS3_DOCID_SEARCH && eSearch!=FTS3_FULLSCAN_SEARCH ){
+    int iCol = eSearch-FTS3_FULLTEXT_SEARCH;
+    const char *zQuery = (const char *)sqlite3_value_text(pCons);
+
+    if( zQuery==0 && sqlite3_value_type(pCons)!=SQLITE_NULL ){
+      return SQLITE_NOMEM;
+    }
+
+    pCsr->iLangid = 0;
+    if( pLangid ) pCsr->iLangid = sqlite3_value_int(pLangid);
+
+    assert( p->base.zErrMsg==0 );
+    rc = sqlite3Fts3ExprParse(p->pTokenizer, pCsr->iLangid,
+        p->azColumn, p->bFts4, p->nColumn, iCol, zQuery, -1, &pCsr->pExpr,
+        &p->base.zErrMsg
+    );
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    rc = fts3EvalStart(pCsr);
+    sqlite3Fts3SegmentsClose(p);
+    if( rc!=SQLITE_OK ) return rc;
+    pCsr->pNextId = pCsr->aDoclist;
+    pCsr->iPrevId = 0;
+  }
+
+  /* Compile a SELECT statement for this cursor. For a full-table-scan, the
+  ** statement loops through all rows of the %_content table. For a
+  ** full-text query or docid lookup, the statement retrieves a single
+  ** row by docid.
+  */
+  if( eSearch==FTS3_FULLSCAN_SEARCH ){
+    if( pDocidGe || pDocidLe ){
+      zSql = sqlite3_mprintf(
+          "SELECT %s WHERE rowid BETWEEN %lld AND %lld ORDER BY rowid %s",
+          p->zReadExprlist, pCsr->iMinDocid, pCsr->iMaxDocid,
+          (pCsr->bDesc ? "DESC" : "ASC")
+      );
+    }else{
+      zSql = sqlite3_mprintf("SELECT %s ORDER BY rowid %s",
+          p->zReadExprlist, (pCsr->bDesc ? "DESC" : "ASC")
+      );
+    }
+    if( zSql ){
+      p->bLock++;
+      rc = sqlite3_prepare_v3(
+          p->db,zSql,-1,SQLITE_PREPARE_PERSISTENT,&pCsr->pStmt,0
+      );
+      p->bLock--;
+      sqlite3_free(zSql);
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }else if( eSearch==FTS3_DOCID_SEARCH ){
+    rc = fts3CursorSeekStmt(pCsr);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_bind_value(pCsr->pStmt, 1, pCons);
+    }
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  return fts3NextMethod(pCursor);
+}
+
+/*
+** This is the xEof method of the virtual table. SQLite calls this
+** routine to find out if it has reached the end of a result set.
+*/
+static int fts3EofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3Cursor *pCsr = (Fts3Cursor*)pCursor;
+  if( pCsr->isEof ){
+    fts3ClearCursor(pCsr);
+    pCsr->isEof = 1;
+  }
+  return pCsr->isEof;
+}
+
+/*
+** This is the xRowid method. The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set. fts3
+** exposes %_content.docid as the rowid for the virtual table. The
+** rowid should be written to *pRowid.
+*/
+static int fts3RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
+  *pRowid = pCsr->iPrevId;
+  return SQLITE_OK;
+}
+
+/*
+** This is the xColumn method, called by SQLite to request a value from
+** the row that the supplied cursor currently points to.
+**
+** If:
+**
+**   (iCol <  p->nColumn)   -> The value of the iCol'th user column.
+**   (iCol == p->nColumn)   -> Magic column with the same name as the table.
+**   (iCol == p->nColumn+1) -> Docid column
+**   (iCol == p->nColumn+2) -> Langid column
+*/
+static int fts3ColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  int rc = SQLITE_OK;             /* Return Code */
+  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
+  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
+
+  /* The column value supplied by SQLite must be in range. */
+  assert( iCol>=0 && iCol<=p->nColumn+2 );
+
+  switch( iCol-p->nColumn ){
+    case 0:
+      /* The special 'table-name' column */
+      sqlite3_result_pointer(pCtx, pCsr, "fts3cursor", 0);
+      break;
+
+    case 1:
+      /* The docid column */
+      sqlite3_result_int64(pCtx, pCsr->iPrevId);
+      break;
+
+    case 2:
+      if( pCsr->pExpr ){
+        sqlite3_result_int64(pCtx, pCsr->iLangid);
+        break;
+      }else if( p->zLanguageid==0 ){
+        sqlite3_result_int(pCtx, 0);
+        break;
+      }else{
+        iCol = p->nColumn;
+        /* no break */ deliberate_fall_through
+      }
+
+    default:
+      /* A user column. Or, if this is a full-table scan, possibly the
+      ** language-id column. Seek the cursor. */
+      rc = fts3CursorSeek(0, pCsr);
+      if( rc==SQLITE_OK && sqlite3_data_count(pCsr->pStmt)-1>iCol ){
+        sqlite3_result_value(pCtx, sqlite3_column_value(pCsr->pStmt, iCol+1));
+      }
+      break;
+  }
+
+  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
+  return rc;
+}
+
+/*
+** This function is the implementation of the xUpdate callback used by
+** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
+** inserted, updated or deleted.
+*/
+static int fts3UpdateMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  return sqlite3Fts3UpdateMethod(pVtab, nArg, apVal, pRowid);
+}
+
+/*
+** Implementation of xSync() method. Flush the contents of the pending-terms
+** hash-table to the database.
+*/
+static int fts3SyncMethod(sqlite3_vtab *pVtab){
+
+  /* Following an incremental-merge operation, assuming that the input
+  ** segments are not completely consumed (the usual case), they are updated
+  ** in place to remove the entries that have already been merged. This
+  ** involves updating the leaf block that contains the smallest unmerged
+  ** entry and each block (if any) between the leaf and the root node. So
+  ** if the height of the input segment b-trees is N, and input segments
+  ** are merged eight at a time, updating the input segments at the end
+  ** of an incremental-merge requires writing (8*(1+N)) blocks. N is usually
+  ** small - often between 0 and 2. So the overhead of the incremental
+  ** merge is somewhere between 8 and 24 blocks. To avoid this overhead
+  ** dwarfing the actual productive work accomplished, the incremental merge
+  ** is only attempted if it will write at least 64 leaf blocks. Hence
+  ** nMinMerge.
+  **
+  ** Of course, updating the input segments also involves deleting a bunch
+  ** of blocks from the segments table. But this is not considered overhead
+  ** as it would also be required by a crisis-merge that used the same input
+  ** segments.
+  */
+  const u32 nMinMerge = 64;       /* Minimum amount of incr-merge work to do */
+
+  Fts3Table *p = (Fts3Table*)pVtab;
+  int rc;
+  i64 iLastRowid = sqlite3_last_insert_rowid(p->db);
+
+  rc = sqlite3Fts3PendingTermsFlush(p);
+  if( rc==SQLITE_OK
+   && p->nLeafAdd>(nMinMerge/16)
+   && p->nAutoincrmerge && p->nAutoincrmerge!=0xff
+  ){
+    int mxLevel = 0;              /* Maximum relative level value in db */
+    int A;                        /* Incr-merge parameter A */
+
+    rc = sqlite3Fts3MaxLevel(p, &mxLevel);
+    assert( rc==SQLITE_OK || mxLevel==0 );
+    A = p->nLeafAdd * mxLevel;
+    A += (A/2);
+    if( A>(int)nMinMerge ) rc = sqlite3Fts3Incrmerge(p, A, p->nAutoincrmerge);
+  }
+  sqlite3Fts3SegmentsClose(p);
+  sqlite3_set_last_insert_rowid(p->db, iLastRowid);
+  return rc;
+}
+
+/*
+** If it is currently unknown whether or not the FTS table has an %_stat
+** table (if p->bHasStat==2), attempt to determine this (set p->bHasStat
+** to 0 or 1). Return SQLITE_OK if successful, or an SQLite error code
+** if an error occurs.
+*/
+static int fts3SetHasStat(Fts3Table *p){
+  int rc = SQLITE_OK;
+  if( p->bHasStat==2 ){
+    char *zTbl = sqlite3_mprintf("%s_stat", p->zName);
+    if( zTbl ){
+      int res = sqlite3_table_column_metadata(p->db, p->zDb, zTbl, 0,0,0,0,0,0);
+      sqlite3_free(zTbl);
+      p->bHasStat = (res==SQLITE_OK);
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+  return rc;
+}
+
+/*
+** Implementation of xBegin() method.
+*/
+static int fts3BeginMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table*)pVtab;
+  int rc;
+  UNUSED_PARAMETER(pVtab);
+  assert( p->pSegments==0 );
+  assert( p->nPendingData==0 );
+  assert( p->inTransaction!=1 );
+  p->nLeafAdd = 0;
+  rc = fts3SetHasStat(p);
+#ifdef SQLITE_DEBUG
+  if( rc==SQLITE_OK ){
+    p->inTransaction = 1;
+    p->mxSavepoint = -1;
+  }
+#endif
+  return rc;
+}
+
+/*
+** Implementation of xCommit() method. This is a no-op. The contents of
+** the pending-terms hash-table have already been flushed into the database
+** by fts3SyncMethod().
+*/
+static int fts3CommitMethod(sqlite3_vtab *pVtab){
+  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
+  UNUSED_PARAMETER(pVtab);
+  assert( p->nPendingData==0 );
+  assert( p->inTransaction!=0 );
+  assert( p->pSegments==0 );
+  TESTONLY( p->inTransaction = 0 );
+  TESTONLY( p->mxSavepoint = -1; );
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xRollback(). Discard the contents of the pending-terms
+** hash-table. Any changes made to the database are reverted by SQLite.
+*/
+static int fts3RollbackMethod(sqlite3_vtab *pVtab){
+  Fts3Table *p = (Fts3Table*)pVtab;
+  sqlite3Fts3PendingTermsClear(p);
+  assert( p->inTransaction!=0 );
+  TESTONLY( p->inTransaction = 0 );
+  TESTONLY( p->mxSavepoint = -1; );
+  return SQLITE_OK;
+}
+
+/*
+** When called, *ppPoslist must point to the byte immediately following the
+** end of a position-list. i.e. ( (*ppPoslist)[-1]==POS_END ). This function
+** moves *ppPoslist so that it instead points to the first byte of the
+** same position list.
+*/
+static void fts3ReversePoslist(char *pStart, char **ppPoslist){
+  char *p = &(*ppPoslist)[-2];
+  char c = 0;
+
+  /* Skip backwards passed any trailing 0x00 bytes added by NearTrim() */
+  while( p>pStart && (c=*p--)==0 );
+
+  /* Search backwards for a varint with value zero (the end of the previous
+  ** poslist). This is an 0x00 byte preceded by some byte that does not
+  ** have the 0x80 bit set.  */
+  while( p>pStart && (*p & 0x80) | c ){
+    c = *p--;
+  }
+  assert( p==pStart || c==0 );
+
+  /* At this point p points to that preceding byte without the 0x80 bit
+  ** set. So to find the start of the poslist, skip forward 2 bytes then
+  ** over a varint.
+  **
+  ** Normally. The other case is that p==pStart and the poslist to return
+  ** is the first in the doclist. In this case do not skip forward 2 bytes.
+  ** The second part of the if condition (c==0 && *ppPoslist>&p[2])
+  ** is required for cases where the first byte of a doclist and the
+  ** doclist is empty. For example, if the first docid is 10, a doclist
+  ** that begins with:
+  **
+  **   0x0A 0x00 <next docid delta varint>
+  */
+  if( p>pStart || (c==0 && *ppPoslist>&p[2]) ){ p = &p[2]; }
+  while( *p++&0x80 );
+  *ppPoslist = p;
+}
+
+/*
+** Helper function used by the implementation of the overloaded snippet(),
+** offsets() and optimize() SQL functions.
+**
+** If the value passed as the third argument is a blob of size
+** sizeof(Fts3Cursor*), then the blob contents are copied to the
+** output variable *ppCsr and SQLITE_OK is returned. Otherwise, an error
+** message is written to context pContext and SQLITE_ERROR returned. The
+** string passed via zFunc is used as part of the error message.
+*/
+static int fts3FunctionArg(
+  sqlite3_context *pContext,      /* SQL function call context */
+  const char *zFunc,              /* Function name */
+  sqlite3_value *pVal,            /* argv[0] passed to function */
+  Fts3Cursor **ppCsr              /* OUT: Store cursor handle here */
+){
+  int rc;
+  *ppCsr = (Fts3Cursor*)sqlite3_value_pointer(pVal, "fts3cursor");
+  if( (*ppCsr)!=0 ){
+    rc = SQLITE_OK;
+  }else{
+    char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
+    sqlite3_result_error(pContext, zErr, -1);
+    sqlite3_free(zErr);
+    rc = SQLITE_ERROR;
+  }
+  return rc;
+}
+
+/*
+** Implementation of the snippet() function for FTS3
+*/
+static void fts3SnippetFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of apVal[] array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+  const char *zStart = "<b>";
+  const char *zEnd = "</b>";
+  const char *zEllipsis = "<b>...</b>";
+  int iCol = -1;
+  int nToken = 15;                /* Default number of tokens in snippet */
+
+  /* There must be at least one argument passed to this function (otherwise
+  ** the non-overloaded version would have been called instead of this one).
+  */
+  assert( nVal>=1 );
+
+  if( nVal>6 ){
+    sqlite3_result_error(pContext,
+        "wrong number of arguments to function snippet()", -1);
+    return;
+  }
+  if( fts3FunctionArg(pContext, "snippet", apVal[0], &pCsr) ) return;
+
+  switch( nVal ){
+    case 6: nToken = sqlite3_value_int(apVal[5]);
+            /* no break */ deliberate_fall_through
+    case 5: iCol = sqlite3_value_int(apVal[4]);
+            /* no break */ deliberate_fall_through
+    case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
+            /* no break */ deliberate_fall_through
+    case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
+            /* no break */ deliberate_fall_through
+    case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
+  }
+  if( !zEllipsis || !zEnd || !zStart ){
+    sqlite3_result_error_nomem(pContext);
+  }else if( nToken==0 ){
+    sqlite3_result_text(pContext, "", -1, SQLITE_STATIC);
+  }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
+    sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis, iCol, nToken);
+  }
+}
+
+/*
+** Implementation of the offsets() function for FTS3
+*/
+static void fts3OffsetsFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+
+  UNUSED_PARAMETER(nVal);
+
+  assert( nVal==1 );
+  if( fts3FunctionArg(pContext, "offsets", apVal[0], &pCsr) ) return;
+  assert( pCsr );
+  if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
+    sqlite3Fts3Offsets(pContext, pCsr);
+  }
+}
+
+/*
+** Implementation of the special optimize() function for FTS3. This
+** function merges all segments in the database to a single segment.
+** Example usage is:
+**
+**   SELECT optimize(t) FROM t LIMIT 1;
+**
+** where 't' is the name of an FTS3 table.
+*/
+static void fts3OptimizeFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  int rc;                         /* Return code */
+  Fts3Table *p;                   /* Virtual table handle */
+  Fts3Cursor *pCursor;            /* Cursor handle passed through apVal[0] */
+
+  UNUSED_PARAMETER(nVal);
+
+  assert( nVal==1 );
+  if( fts3FunctionArg(pContext, "optimize", apVal[0], &pCursor) ) return;
+  p = (Fts3Table *)pCursor->base.pVtab;
+  assert( p );
+
+  rc = sqlite3Fts3Optimize(p);
+
+  switch( rc ){
+    case SQLITE_OK:
+      sqlite3_result_text(pContext, "Index optimized", -1, SQLITE_STATIC);
+      break;
+    case SQLITE_DONE:
+      sqlite3_result_text(pContext, "Index already optimal", -1, SQLITE_STATIC);
+      break;
+    default:
+      sqlite3_result_error_code(pContext, rc);
+      break;
+  }
+}
+
+/*
+** Implementation of the matchinfo() function for FTS3
+*/
+static void fts3MatchinfoFunc(
+  sqlite3_context *pContext,      /* SQLite function call context */
+  int nVal,                       /* Size of argument array */
+  sqlite3_value **apVal           /* Array of arguments */
+){
+  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
+  assert( nVal==1 || nVal==2 );
+  if( SQLITE_OK==fts3FunctionArg(pContext, "matchinfo", apVal[0], &pCsr) ){
+    const char *zArg = 0;
+    if( nVal>1 ){
+      zArg = (const char *)sqlite3_value_text(apVal[1]);
+    }
+    sqlite3Fts3Matchinfo(pContext, pCsr, zArg);
+  }
+}
+
+/*
+** This routine implements the xFindFunction method for the FTS3
+** virtual table.
+*/
+static int fts3FindFunctionMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Number of SQL function arguments */
+  const char *zName,              /* Name of SQL function */
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
+  void **ppArg                    /* Unused */
+){
+  struct Overloaded {
+    const char *zName;
+    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  } aOverload[] = {
+    { "snippet", fts3SnippetFunc },
+    { "offsets", fts3OffsetsFunc },
+    { "optimize", fts3OptimizeFunc },
+    { "matchinfo", fts3MatchinfoFunc },
+  };
+  int i;                          /* Iterator variable */
+
+  UNUSED_PARAMETER(pVtab);
+  UNUSED_PARAMETER(nArg);
+  UNUSED_PARAMETER(ppArg);
+
+  for(i=0; i<SizeofArray(aOverload); i++){
+    if( strcmp(zName, aOverload[i].zName)==0 ){
+      *pxFunc = aOverload[i].xFunc;
+      return 1;
+    }
+  }
+
+  /* No function of the specified name was found. Return 0. */
+  return 0;
+}
+
+/*
+** Implementation of FTS3 xRename method. Rename an fts3 table.
+*/
+static int fts3RenameMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  const char *zName               /* New name of table */
+){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  sqlite3 *db = p->db;            /* Database connection */
+  int rc;                         /* Return Code */
+
+  /* At this point it must be known if the %_stat table exists or not.
+  ** So bHasStat may not be 2.  */
+  rc = fts3SetHasStat(p);
+
+  /* As it happens, the pending terms table is always empty here. This is
+  ** because an "ALTER TABLE RENAME TABLE" statement inside a transaction
+  ** always opens a savepoint transaction. And the xSavepoint() method
+  ** flushes the pending terms table. But leave the (no-op) call to
+  ** PendingTermsFlush() in in case that changes.
+  */
+  assert( p->nPendingData==0 );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3PendingTermsFlush(p);
+  }
+
+  p->bIgnoreSavepoint = 1;
+
+  if( p->zContentTbl==0 ){
+    fts3DbExec(&rc, db,
+      "ALTER TABLE %Q.'%q_content'  RENAME TO '%q_content';",
+      p->zDb, p->zName, zName
+    );
+  }
+
+  if( p->bHasDocsize ){
+    fts3DbExec(&rc, db,
+      "ALTER TABLE %Q.'%q_docsize'  RENAME TO '%q_docsize';",
+      p->zDb, p->zName, zName
+    );
+  }
+  if( p->bHasStat ){
+    fts3DbExec(&rc, db,
+      "ALTER TABLE %Q.'%q_stat'  RENAME TO '%q_stat';",
+      p->zDb, p->zName, zName
+    );
+  }
+  fts3DbExec(&rc, db,
+    "ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';",
+    p->zDb, p->zName, zName
+  );
+  fts3DbExec(&rc, db,
+    "ALTER TABLE %Q.'%q_segdir'   RENAME TO '%q_segdir';",
+    p->zDb, p->zName, zName
+  );
+
+  p->bIgnoreSavepoint = 0;
+  return rc;
+}
+
+/*
+** The xSavepoint() method.
+**
+** Flush the contents of the pending-terms table to disk.
+*/
+static int fts3SavepointMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  int rc = SQLITE_OK;
+  Fts3Table *pTab = (Fts3Table*)pVtab;
+  assert( pTab->inTransaction );
+  assert( pTab->mxSavepoint<=iSavepoint );
+  TESTONLY( pTab->mxSavepoint = iSavepoint );
+
+  if( pTab->bIgnoreSavepoint==0 ){
+    if( fts3HashCount(&pTab->aIndex[0].hPending)>0 ){
+      char *zSql = sqlite3_mprintf("INSERT INTO %Q.%Q(%Q) VALUES('flush')",
+          pTab->zDb, pTab->zName, pTab->zName
+          );
+      if( zSql ){
+        pTab->bIgnoreSavepoint = 1;
+        rc = sqlite3_exec(pTab->db, zSql, 0, 0, 0);
+        pTab->bIgnoreSavepoint = 0;
+        sqlite3_free(zSql);
+      }else{
+        rc = SQLITE_NOMEM;
+      }
+    }
+    if( rc==SQLITE_OK ){
+      pTab->iSavepoint = iSavepoint+1;
+    }
+  }
+  return rc;
+}
+
+/*
+** The xRelease() method.
+**
+** This is a no-op.
+*/
+static int fts3ReleaseMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts3Table *pTab = (Fts3Table*)pVtab;
+  assert( pTab->inTransaction );
+  assert( pTab->mxSavepoint >= iSavepoint );
+  TESTONLY( pTab->mxSavepoint = iSavepoint-1 );
+  pTab->iSavepoint = iSavepoint;
+  return SQLITE_OK;
+}
+
+/*
+** The xRollbackTo() method.
+**
+** Discard the contents of the pending terms table.
+*/
+static int fts3RollbackToMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts3Table *pTab = (Fts3Table*)pVtab;
+  UNUSED_PARAMETER(iSavepoint);
+  assert( pTab->inTransaction );
+  TESTONLY( pTab->mxSavepoint = iSavepoint );
+  if( (iSavepoint+1)<=pTab->iSavepoint ){
+    sqlite3Fts3PendingTermsClear(pTab);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return true if zName is the extension on one of the shadow tables used
+** by this module.
+*/
+static int fts3ShadowName(const char *zName){
+  static const char *azName[] = {
+    "content", "docsize", "segdir", "segments", "stat",
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
+    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Implementation of the xIntegrity() method on the FTS3/FTS4 virtual
+** table.
+*/
+static int fts3IntegrityMethod(
+  sqlite3_vtab *pVtab,      /* The virtual table to be checked */
+  const char *zSchema,      /* Name of schema in which pVtab lives */
+  const char *zTabname,     /* Name of the pVTab table */
+  int isQuick,              /* True if this is a quick_check */
+  char **pzErr              /* Write error message here */
+){
+  Fts3Table *p = (Fts3Table*)pVtab;
+  int rc = SQLITE_OK;
+  int bOk = 0;
+
+  UNUSED_PARAMETER(isQuick);
+  rc = sqlite3Fts3IntegrityCheck(p, &bOk);
+  assert( rc!=SQLITE_CORRUPT_VTAB );
+  if( rc==SQLITE_ERROR || (rc&0xFF)==SQLITE_CORRUPT ){
+    *pzErr = sqlite3_mprintf("unable to validate the inverted index for"
+                             " FTS%d table %s.%s: %s",
+                p->bFts4 ? 4 : 3, zSchema, zTabname, sqlite3_errstr(rc));
+    if( *pzErr ) rc = SQLITE_OK;
+  }else if( rc==SQLITE_OK && bOk==0 ){
+    *pzErr = sqlite3_mprintf("malformed inverted index for FTS%d table %s.%s",
+                p->bFts4 ? 4 : 3, zSchema, zTabname);
+    if( *pzErr==0 ) rc = SQLITE_NOMEM;
+  }
+  sqlite3Fts3SegmentsClose(p);
+  return rc;
+}
+
+
+
+static const sqlite3_module fts3Module = {
+  /* iVersion      */ 4,
+  /* xCreate       */ fts3CreateMethod,
+  /* xConnect      */ fts3ConnectMethod,
+  /* xBestIndex    */ fts3BestIndexMethod,
+  /* xDisconnect   */ fts3DisconnectMethod,
+  /* xDestroy      */ fts3DestroyMethod,
+  /* xOpen         */ fts3OpenMethod,
+  /* xClose        */ fts3CloseMethod,
+  /* xFilter       */ fts3FilterMethod,
+  /* xNext         */ fts3NextMethod,
+  /* xEof          */ fts3EofMethod,
+  /* xColumn       */ fts3ColumnMethod,
+  /* xRowid        */ fts3RowidMethod,
+  /* xUpdate       */ fts3UpdateMethod,
+  /* xBegin        */ fts3BeginMethod,
+  /* xSync         */ fts3SyncMethod,
+  /* xCommit       */ fts3CommitMethod,
+  /* xRollback     */ fts3RollbackMethod,
+  /* xFindFunction */ fts3FindFunctionMethod,
+  /* xRename */       fts3RenameMethod,
+  /* xSavepoint    */ fts3SavepointMethod,
+  /* xRelease      */ fts3ReleaseMethod,
+  /* xRollbackTo   */ fts3RollbackToMethod,
+  /* xShadowName   */ fts3ShadowName,
+  /* xIntegrity    */ fts3IntegrityMethod,
+};
+
+/*
+** This function is registered as the module destructor (called when an
+** FTS3 enabled database connection is closed). It frees the memory
+** allocated for the tokenizer hash table.
+*/
+static void hashDestroy(void *p){
+  Fts3HashWrapper *pHash = (Fts3HashWrapper *)p;
+  pHash->nRef--;
+  if( pHash->nRef<=0 ){
+    sqlite3Fts3HashClear(&pHash->hash);
+    sqlite3_free(pHash);
+  }
+}
+
+/*
+** The fts3 built-in tokenizers - "simple", "porter" and "icu"- are
+** implemented in files fts3_tokenizer1.c, fts3_porter.c and fts3_icu.c
+** respectively. The following three forward declarations are for functions
+** declared in these files used to retrieve the respective implementations.
+**
+** Calling sqlite3Fts3SimpleTokenizerModule() sets the value pointed
+** to by the argument to point to the "simple" tokenizer implementation.
+** And so on.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+SQLITE_PRIVATE void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const**ppModule);
+#endif
+#ifdef SQLITE_ENABLE_ICU
+SQLITE_PRIVATE void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+#endif
+
+/*
+** Initialize the fts3 extension. If this extension is built as part
+** of the sqlite library, then this function is called directly by
+** SQLite. If fts3 is built as a dynamically loadable extension, this
+** function is called by the sqlite3_extension_init() entry point.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Init(sqlite3 *db){
+  int rc = SQLITE_OK;
+  Fts3HashWrapper *pHash = 0;
+  const sqlite3_tokenizer_module *pSimple = 0;
+  const sqlite3_tokenizer_module *pPorter = 0;
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+  const sqlite3_tokenizer_module *pUnicode = 0;
+#endif
+
+#ifdef SQLITE_ENABLE_ICU
+  const sqlite3_tokenizer_module *pIcu = 0;
+  sqlite3Fts3IcuTokenizerModule(&pIcu);
+#endif
+
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+  sqlite3Fts3UnicodeTokenizer(&pUnicode);
+#endif
+
+#ifdef SQLITE_TEST
+  rc = sqlite3Fts3InitTerm(db);
+  if( rc!=SQLITE_OK ) return rc;
+#endif
+
+  rc = sqlite3Fts3InitAux(db);
+  if( rc!=SQLITE_OK ) return rc;
+
+  sqlite3Fts3SimpleTokenizerModule(&pSimple);
+  sqlite3Fts3PorterTokenizerModule(&pPorter);
+
+  /* Allocate and initialize the hash-table used to store tokenizers. */
+  pHash = sqlite3_malloc(sizeof(Fts3HashWrapper));
+  if( !pHash ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3Fts3HashInit(&pHash->hash, FTS3_HASH_STRING, 1);
+    pHash->nRef = 0;
+  }
+
+  /* Load the built-in tokenizers into the hash table */
+  if( rc==SQLITE_OK ){
+    if( sqlite3Fts3HashInsert(&pHash->hash, "simple", 7, (void *)pSimple)
+     || sqlite3Fts3HashInsert(&pHash->hash, "porter", 7, (void *)pPorter)
+
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+     || sqlite3Fts3HashInsert(&pHash->hash, "unicode61", 10, (void *)pUnicode)
+#endif
+#ifdef SQLITE_ENABLE_ICU
+     || (pIcu && sqlite3Fts3HashInsert(&pHash->hash, "icu", 4, (void *)pIcu))
+#endif
+    ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+#ifdef SQLITE_TEST
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3ExprInitTestInterface(db, &pHash->hash);
+  }
+#endif
+
+  /* Create the virtual table wrapper around the hash-table and overload
+  ** the four scalar functions. If this is successful, register the
+  ** module with sqlite.
+  */
+  if( SQLITE_OK==rc
+   && SQLITE_OK==(rc=sqlite3Fts3InitHashTable(db,&pHash->hash,"fts3_tokenizer"))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 1))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 2))
+   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
+  ){
+    pHash->nRef++;
+    rc = sqlite3_create_module_v2(
+        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
+    );
+    if( rc==SQLITE_OK ){
+      pHash->nRef++;
+      rc = sqlite3_create_module_v2(
+          db, "fts4", &fts3Module, (void *)pHash, hashDestroy
+      );
+    }
+    if( rc==SQLITE_OK ){
+      pHash->nRef++;
+      rc = sqlite3Fts3InitTok(db, (void *)pHash, hashDestroy);
+    }
+    return rc;
+  }
+
+
+  /* An error has occurred. Delete the hash table and return the error code. */
+  assert( rc!=SQLITE_OK );
+  if( pHash ){
+    sqlite3Fts3HashClear(&pHash->hash);
+    sqlite3_free(pHash);
+  }
+  return rc;
+}
+
+/*
+** Allocate an Fts3MultiSegReader for each token in the expression headed
+** by pExpr.
+**
+** An Fts3SegReader object is a cursor that can seek or scan a range of
+** entries within a single segment b-tree. An Fts3MultiSegReader uses multiple
+** Fts3SegReader objects internally to provide an interface to seek or scan
+** within the union of all segments of a b-tree. Hence the name.
+**
+** If the allocated Fts3MultiSegReader just seeks to a single entry in a
+** segment b-tree (if the term is not a prefix or it is a prefix for which
+** there exists prefix b-tree of the right length) then it may be traversed
+** and merged incrementally. Otherwise, it has to be merged into an in-memory
+** doclist and then traversed.
+*/
+static void fts3EvalAllocateReaders(
+  Fts3Cursor *pCsr,               /* FTS cursor handle */
+  Fts3Expr *pExpr,                /* Allocate readers for this expression */
+  int *pnToken,                   /* OUT: Total number of tokens in phrase. */
+  int *pnOr,                      /* OUT: Total number of OR nodes in expr. */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( pExpr && SQLITE_OK==*pRc ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      int i;
+      int nToken = pExpr->pPhrase->nToken;
+      *pnToken += nToken;
+      for(i=0; i<nToken; i++){
+        Fts3PhraseToken *pToken = &pExpr->pPhrase->aToken[i];
+        int rc = fts3TermSegReaderCursor(pCsr,
+            pToken->z, pToken->n, pToken->isPrefix, &pToken->pSegcsr
+        );
+        if( rc!=SQLITE_OK ){
+          *pRc = rc;
+          return;
+        }
+      }
+      assert( pExpr->pPhrase->iDoclistToken==0 );
+      pExpr->pPhrase->iDoclistToken = -1;
+    }else{
+      *pnOr += (pExpr->eType==FTSQUERY_OR);
+      fts3EvalAllocateReaders(pCsr, pExpr->pLeft, pnToken, pnOr, pRc);
+      fts3EvalAllocateReaders(pCsr, pExpr->pRight, pnToken, pnOr, pRc);
+    }
+  }
+}
+
+/*
+** Arguments pList/nList contain the doclist for token iToken of phrase p.
+** It is merged into the main doclist stored in p->doclist.aAll/nAll.
+**
+** This function assumes that pList points to a buffer allocated using
+** sqlite3_malloc(). This function takes responsibility for eventually
+** freeing the buffer.
+**
+** SQLITE_OK is returned if successful, or SQLITE_NOMEM if an error occurs.
+*/
+static int fts3EvalPhraseMergeToken(
+  Fts3Table *pTab,                /* FTS Table pointer */
+  Fts3Phrase *p,                  /* Phrase to merge pList/nList into */
+  int iToken,                     /* Token pList/nList corresponds to */
+  char *pList,                    /* Pointer to doclist */
+  int nList                       /* Number of bytes in pList */
+){
+  int rc = SQLITE_OK;
+  assert( iToken!=p->iDoclistToken );
+
+  if( pList==0 ){
+    sqlite3_free(p->doclist.aAll);
+    p->doclist.aAll = 0;
+    p->doclist.nAll = 0;
+  }
+
+  else if( p->iDoclistToken<0 ){
+    p->doclist.aAll = pList;
+    p->doclist.nAll = nList;
+  }
+
+  else if( p->doclist.aAll==0 ){
+    sqlite3_free(pList);
+  }
+
+  else {
+    char *pLeft;
+    char *pRight;
+    int nLeft;
+    int nRight;
+    int nDiff;
+
+    if( p->iDoclistToken<iToken ){
+      pLeft = p->doclist.aAll;
+      nLeft = p->doclist.nAll;
+      pRight = pList;
+      nRight = nList;
+      nDiff = iToken - p->iDoclistToken;
+    }else{
+      pRight = p->doclist.aAll;
+      nRight = p->doclist.nAll;
+      pLeft = pList;
+      nLeft = nList;
+      nDiff = p->iDoclistToken - iToken;
+    }
+
+    rc = fts3DoclistPhraseMerge(
+        pTab->bDescIdx, nDiff, pLeft, nLeft, &pRight, &nRight
+    );
+    sqlite3_free(pLeft);
+    p->doclist.aAll = pRight;
+    p->doclist.nAll = nRight;
+  }
+
+  if( iToken>p->iDoclistToken ) p->iDoclistToken = iToken;
+  return rc;
+}
+
+/*
+** Load the doclist for phrase p into p->doclist.aAll/nAll. The loaded doclist
+** does not take deferred tokens into account.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3EvalPhraseLoad(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Phrase *p                   /* Phrase object */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int iToken;
+  int rc = SQLITE_OK;
+
+  for(iToken=0; rc==SQLITE_OK && iToken<p->nToken; iToken++){
+    Fts3PhraseToken *pToken = &p->aToken[iToken];
+    assert( pToken->pDeferred==0 || pToken->pSegcsr==0 );
+
+    if( pToken->pSegcsr ){
+      int nThis = 0;
+      char *pThis = 0;
+      rc = fts3TermSelect(pTab, pToken, p->iColumn, &nThis, &pThis);
+      if( rc==SQLITE_OK ){
+        rc = fts3EvalPhraseMergeToken(pTab, p, iToken, pThis, nThis);
+      }
+    }
+    assert( pToken->pSegcsr==0 );
+  }
+
+  return rc;
+}
+
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+/*
+** This function is called on each phrase after the position lists for
+** any deferred tokens have been loaded into memory. It updates the phrases
+** current position list to include only those positions that are really
+** instances of the phrase (after considering deferred tokens). If this
+** means that the phrase does not appear in the current row, doclist.pList
+** and doclist.nList are both zeroed.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
+  int iToken;                     /* Used to iterate through phrase tokens */
+  char *aPoslist = 0;             /* Position list for deferred tokens */
+  int nPoslist = 0;               /* Number of bytes in aPoslist */
+  int iPrev = -1;                 /* Token number of previous deferred token */
+  char *aFree = (pPhrase->doclist.bFreeList ? pPhrase->doclist.pList : 0);
+
+  for(iToken=0; iToken<pPhrase->nToken; iToken++){
+    Fts3PhraseToken *pToken = &pPhrase->aToken[iToken];
+    Fts3DeferredToken *pDeferred = pToken->pDeferred;
+
+    if( pDeferred ){
+      char *pList;
+      int nList;
+      int rc = sqlite3Fts3DeferredTokenList(pDeferred, &pList, &nList);
+      if( rc!=SQLITE_OK ) return rc;
+
+      if( pList==0 ){
+        sqlite3_free(aPoslist);
+        sqlite3_free(aFree);
+        pPhrase->doclist.pList = 0;
+        pPhrase->doclist.nList = 0;
+        return SQLITE_OK;
+
+      }else if( aPoslist==0 ){
+        aPoslist = pList;
+        nPoslist = nList;
+
+      }else{
+        char *aOut = pList;
+        char *p1 = aPoslist;
+        char *p2 = aOut;
+
+        assert( iPrev>=0 );
+        fts3PoslistPhraseMerge(&aOut, iToken-iPrev, 0, 1, &p1, &p2);
+        sqlite3_free(aPoslist);
+        aPoslist = pList;
+        nPoslist = (int)(aOut - aPoslist);
+        if( nPoslist==0 ){
+          sqlite3_free(aPoslist);
+          sqlite3_free(aFree);
+          pPhrase->doclist.pList = 0;
+          pPhrase->doclist.nList = 0;
+          return SQLITE_OK;
+        }
+      }
+      iPrev = iToken;
+    }
+  }
+
+  if( iPrev>=0 ){
+    int nMaxUndeferred = pPhrase->iDoclistToken;
+    if( nMaxUndeferred<0 ){
+      pPhrase->doclist.pList = aPoslist;
+      pPhrase->doclist.nList = nPoslist;
+      pPhrase->doclist.iDocid = pCsr->iPrevId;
+      pPhrase->doclist.bFreeList = 1;
+    }else{
+      int nDistance;
+      char *p1;
+      char *p2;
+      char *aOut;
+
+      if( nMaxUndeferred>iPrev ){
+        p1 = aPoslist;
+        p2 = pPhrase->doclist.pList;
+        nDistance = nMaxUndeferred - iPrev;
+      }else{
+        p1 = pPhrase->doclist.pList;
+        p2 = aPoslist;
+        nDistance = iPrev - nMaxUndeferred;
+      }
+
+      aOut = (char *)sqlite3Fts3MallocZero(nPoslist+FTS3_BUFFER_PADDING);
+      if( !aOut ){
+        sqlite3_free(aPoslist);
+        return SQLITE_NOMEM;
+      }
+
+      pPhrase->doclist.pList = aOut;
+      assert( p1 && p2 );
+      if( fts3PoslistPhraseMerge(&aOut, nDistance, 0, 1, &p1, &p2) ){
+        pPhrase->doclist.bFreeList = 1;
+        pPhrase->doclist.nList = (int)(aOut - pPhrase->doclist.pList);
+      }else{
+        sqlite3_free(aOut);
+        pPhrase->doclist.pList = 0;
+        pPhrase->doclist.nList = 0;
+      }
+      sqlite3_free(aPoslist);
+    }
+  }
+
+  if( pPhrase->doclist.pList!=aFree ) sqlite3_free(aFree);
+  return SQLITE_OK;
+}
+#endif /* SQLITE_DISABLE_FTS4_DEFERRED */
+
+/*
+** Maximum number of tokens a phrase may have to be considered for the
+** incremental doclists strategy.
+*/
+#define MAX_INCR_PHRASE_TOKENS 4
+
+/*
+** This function is called for each Fts3Phrase in a full-text query
+** expression to initialize the mechanism for returning rows. Once this
+** function has been called successfully on an Fts3Phrase, it may be
+** used with fts3EvalPhraseNext() to iterate through the matching docids.
+**
+** If parameter bOptOk is true, then the phrase may (or may not) use the
+** incremental loading strategy. Otherwise, the entire doclist is loaded into
+** memory within this call.
+**
+** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
+*/
+static int fts3EvalPhraseStart(Fts3Cursor *pCsr, int bOptOk, Fts3Phrase *p){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;             /* Error code */
+  int i;
+
+  /* Determine if doclists may be loaded from disk incrementally. This is
+  ** possible if the bOptOk argument is true, the FTS doclists will be
+  ** scanned in forward order, and the phrase consists of
+  ** MAX_INCR_PHRASE_TOKENS or fewer tokens, none of which are are "^first"
+  ** tokens or prefix tokens that cannot use a prefix-index.  */
+  int bHaveIncr = 0;
+  int bIncrOk = (bOptOk
+   && pCsr->bDesc==pTab->bDescIdx
+   && p->nToken<=MAX_INCR_PHRASE_TOKENS && p->nToken>0
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+   && pTab->bNoIncrDoclist==0
+#endif
+  );
+  for(i=0; bIncrOk==1 && i<p->nToken; i++){
+    Fts3PhraseToken *pToken = &p->aToken[i];
+    if( pToken->bFirst || (pToken->pSegcsr!=0 && !pToken->pSegcsr->bLookup) ){
+      bIncrOk = 0;
+    }
+    if( pToken->pSegcsr ) bHaveIncr = 1;
+  }
+
+  if( bIncrOk && bHaveIncr ){
+    /* Use the incremental approach. */
+    int iCol = (p->iColumn >= pTab->nColumn ? -1 : p->iColumn);
+    for(i=0; rc==SQLITE_OK && i<p->nToken; i++){
+      Fts3PhraseToken *pToken = &p->aToken[i];
+      Fts3MultiSegReader *pSegcsr = pToken->pSegcsr;
+      if( pSegcsr ){
+        rc = sqlite3Fts3MsrIncrStart(pTab, pSegcsr, iCol, pToken->z, pToken->n);
+      }
+    }
+    p->bIncr = 1;
+  }else{
+    /* Load the full doclist for the phrase into memory. */
+    rc = fts3EvalPhraseLoad(pCsr, p);
+    p->bIncr = 0;
+  }
+
+  assert( rc!=SQLITE_OK || p->nToken<1 || p->aToken[0].pSegcsr==0 || p->bIncr );
+  return rc;
+}
+
+/*
+** This function is used to iterate backwards (from the end to start)
+** through doclists. It is used by this module to iterate through phrase
+** doclists in reverse and by the fts3_write.c module to iterate through
+** pending-terms lists when writing to databases with "order=desc".
+**
+** The doclist may be sorted in ascending (parameter bDescIdx==0) or
+** descending (parameter bDescIdx==1) order of docid. Regardless, this
+** function iterates from the end of the doclist to the beginning.
+*/
+SQLITE_PRIVATE void sqlite3Fts3DoclistPrev(
+  int bDescIdx,                   /* True if the doclist is desc */
+  char *aDoclist,                 /* Pointer to entire doclist */
+  int nDoclist,                   /* Length of aDoclist in bytes */
+  char **ppIter,                  /* IN/OUT: Iterator pointer */
+  sqlite3_int64 *piDocid,         /* IN/OUT: Docid pointer */
+  int *pnList,                    /* OUT: List length pointer */
+  u8 *pbEof                       /* OUT: End-of-file flag */
+){
+  char *p = *ppIter;
+
+  assert( nDoclist>0 );
+  assert( *pbEof==0 );
+  assert_fts3_nc( p || *piDocid==0 );
+  assert( !p || (p>aDoclist && p<&aDoclist[nDoclist]) );
+
+  if( p==0 ){
+    sqlite3_int64 iDocid = 0;
+    char *pNext = 0;
+    char *pDocid = aDoclist;
+    char *pEnd = &aDoclist[nDoclist];
+    int iMul = 1;
+
+    while( pDocid<pEnd ){
+      sqlite3_int64 iDelta;
+      pDocid += sqlite3Fts3GetVarint(pDocid, &iDelta);
+      iDocid += (iMul * iDelta);
+      pNext = pDocid;
+      fts3PoslistCopy(0, &pDocid);
+      while( pDocid<pEnd && *pDocid==0 ) pDocid++;
+      iMul = (bDescIdx ? -1 : 1);
+    }
+
+    *pnList = (int)(pEnd - pNext);
+    *ppIter = pNext;
+    *piDocid = iDocid;
+  }else{
+    int iMul = (bDescIdx ? -1 : 1);
+    sqlite3_int64 iDelta;
+    fts3GetReverseVarint(&p, aDoclist, &iDelta);
+    *piDocid -= (iMul * iDelta);
+
+    if( p==aDoclist ){
+      *pbEof = 1;
+    }else{
+      char *pSave = p;
+      fts3ReversePoslist(aDoclist, &p);
+      *pnList = (int)(pSave - p);
+    }
+    *ppIter = p;
+  }
+}
+
+/*
+** Iterate forwards through a doclist.
+*/
+SQLITE_PRIVATE void sqlite3Fts3DoclistNext(
+  int bDescIdx,                   /* True if the doclist is desc */
+  char *aDoclist,                 /* Pointer to entire doclist */
+  int nDoclist,                   /* Length of aDoclist in bytes */
+  char **ppIter,                  /* IN/OUT: Iterator pointer */
+  sqlite3_int64 *piDocid,         /* IN/OUT: Docid pointer */
+  u8 *pbEof                       /* OUT: End-of-file flag */
+){
+  char *p = *ppIter;
+
+  assert( nDoclist>0 );
+  assert( *pbEof==0 );
+  assert_fts3_nc( p || *piDocid==0 );
+  assert( !p || (p>=aDoclist && p<=&aDoclist[nDoclist]) );
+
+  if( p==0 ){
+    p = aDoclist;
+    p += sqlite3Fts3GetVarint(p, piDocid);
+  }else{
+    fts3PoslistCopy(0, &p);
+    while( p<&aDoclist[nDoclist] && *p==0 ) p++;
+    if( p>=&aDoclist[nDoclist] ){
+      *pbEof = 1;
+    }else{
+      sqlite3_int64 iVar;
+      p += sqlite3Fts3GetVarint(p, &iVar);
+      *piDocid += ((bDescIdx ? -1 : 1) * iVar);
+    }
+  }
+
+  *ppIter = p;
+}
+
+/*
+** Advance the iterator pDL to the next entry in pDL->aAll/nAll. Set *pbEof
+** to true if EOF is reached.
+*/
+static void fts3EvalDlPhraseNext(
+  Fts3Table *pTab,
+  Fts3Doclist *pDL,
+  u8 *pbEof
+){
+  char *pIter;                            /* Used to iterate through aAll */
+  char *pEnd;                             /* 1 byte past end of aAll */
+
+  if( pDL->pNextDocid ){
+    pIter = pDL->pNextDocid;
+    assert( pDL->aAll!=0 || pIter==0 );
+  }else{
+    pIter = pDL->aAll;
+  }
+
+  if( pIter==0 || pIter>=(pEnd = pDL->aAll + pDL->nAll) ){
+    /* We have already reached the end of this doclist. EOF. */
+    *pbEof = 1;
+  }else{
+    sqlite3_int64 iDelta;
+    pIter += sqlite3Fts3GetVarint(pIter, &iDelta);
+    if( pTab->bDescIdx==0 || pDL->pNextDocid==0 ){
+      pDL->iDocid += iDelta;
+    }else{
+      pDL->iDocid -= iDelta;
+    }
+    pDL->pList = pIter;
+    fts3PoslistCopy(0, &pIter);
+    pDL->nList = (int)(pIter - pDL->pList);
+
+    /* pIter now points just past the 0x00 that terminates the position-
+    ** list for document pDL->iDocid. However, if this position-list was
+    ** edited in place by fts3EvalNearTrim(), then pIter may not actually
+    ** point to the start of the next docid value. The following line deals
+    ** with this case by advancing pIter past the zero-padding added by
+    ** fts3EvalNearTrim().  */
+    while( pIter<pEnd && *pIter==0 ) pIter++;
+
+    pDL->pNextDocid = pIter;
+    assert( pIter>=&pDL->aAll[pDL->nAll] || *pIter );
+    *pbEof = 0;
+  }
+}
+
+/*
+** Helper type used by fts3EvalIncrPhraseNext() and incrPhraseTokenNext().
+*/
+typedef struct TokenDoclist TokenDoclist;
+struct TokenDoclist {
+  int bIgnore;
+  sqlite3_int64 iDocid;
+  char *pList;
+  int nList;
+};
+
+/*
+** Token pToken is an incrementally loaded token that is part of a
+** multi-token phrase. Advance it to the next matching document in the
+** database and populate output variable *p with the details of the new
+** entry. Or, if the iterator has reached EOF, set *pbEof to true.
+**
+** If an error occurs, return an SQLite error code. Otherwise, return
+** SQLITE_OK.
+*/
+static int incrPhraseTokenNext(
+  Fts3Table *pTab,                /* Virtual table handle */
+  Fts3Phrase *pPhrase,            /* Phrase to advance token of */
+  int iToken,                     /* Specific token to advance */
+  TokenDoclist *p,                /* OUT: Docid and doclist for new entry */
+  u8 *pbEof                       /* OUT: True if iterator is at EOF */
+){
+  int rc = SQLITE_OK;
+
+  if( pPhrase->iDoclistToken==iToken ){
+    assert( p->bIgnore==0 );
+    assert( pPhrase->aToken[iToken].pSegcsr==0 );
+    fts3EvalDlPhraseNext(pTab, &pPhrase->doclist, pbEof);
+    p->pList = pPhrase->doclist.pList;
+    p->nList = pPhrase->doclist.nList;
+    p->iDocid = pPhrase->doclist.iDocid;
+  }else{
+    Fts3PhraseToken *pToken = &pPhrase->aToken[iToken];
+    assert( pToken->pDeferred==0 );
+    assert( pToken->pSegcsr || pPhrase->iDoclistToken>=0 );
+    if( pToken->pSegcsr ){
+      assert( p->bIgnore==0 );
+      rc = sqlite3Fts3MsrIncrNext(
+          pTab, pToken->pSegcsr, &p->iDocid, &p->pList, &p->nList
+      );
+      if( p->pList==0 ) *pbEof = 1;
+    }else{
+      p->bIgnore = 1;
+    }
+  }
+
+  return rc;
+}
+
+
+/*
+** The phrase iterator passed as the second argument:
+**
+**   * features at least one token that uses an incremental doclist, and
+**
+**   * does not contain any deferred tokens.
+**
+** Advance it to the next matching documnent in the database and populate
+** the Fts3Doclist.pList and nList fields.
+**
+** If there is no "next" entry and no error occurs, then *pbEof is set to
+** 1 before returning. Otherwise, if no error occurs and the iterator is
+** successfully advanced, *pbEof is set to 0.
+**
+** If an error occurs, return an SQLite error code. Otherwise, return
+** SQLITE_OK.
+*/
+static int fts3EvalIncrPhraseNext(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Phrase *p,                  /* Phrase object to advance to next docid */
+  u8 *pbEof                       /* OUT: Set to 1 if EOF */
+){
+  int rc = SQLITE_OK;
+  Fts3Doclist *pDL = &p->doclist;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  u8 bEof = 0;
+
+  /* This is only called if it is guaranteed that the phrase has at least
+  ** one incremental token. In which case the bIncr flag is set. */
+  assert( p->bIncr==1 );
+
+  if( p->nToken==1 ){
+    rc = sqlite3Fts3MsrIncrNext(pTab, p->aToken[0].pSegcsr,
+        &pDL->iDocid, &pDL->pList, &pDL->nList
+    );
+    if( pDL->pList==0 ) bEof = 1;
+  }else{
+    int bDescDoclist = pCsr->bDesc;
+    struct TokenDoclist a[MAX_INCR_PHRASE_TOKENS];
+
+    memset(a, 0, sizeof(a));
+    assert( p->nToken<=MAX_INCR_PHRASE_TOKENS );
+    assert( p->iDoclistToken<MAX_INCR_PHRASE_TOKENS );
+
+    while( bEof==0 ){
+      int bMaxSet = 0;
+      sqlite3_int64 iMax = 0;     /* Largest docid for all iterators */
+      int i;                      /* Used to iterate through tokens */
+
+      /* Advance the iterator for each token in the phrase once. */
+      for(i=0; rc==SQLITE_OK && i<p->nToken && bEof==0; i++){
+        rc = incrPhraseTokenNext(pTab, p, i, &a[i], &bEof);
+        if( a[i].bIgnore==0 && (bMaxSet==0 || DOCID_CMP(iMax, a[i].iDocid)<0) ){
+          iMax = a[i].iDocid;
+          bMaxSet = 1;
+        }
+      }
+      assert( rc!=SQLITE_OK || (p->nToken>=1 && a[p->nToken-1].bIgnore==0) );
+      assert( rc!=SQLITE_OK || bMaxSet );
+
+      /* Keep advancing iterators until they all point to the same document */
+      for(i=0; i<p->nToken; i++){
+        while( rc==SQLITE_OK && bEof==0
+            && a[i].bIgnore==0 && DOCID_CMP(a[i].iDocid, iMax)<0
+        ){
+          rc = incrPhraseTokenNext(pTab, p, i, &a[i], &bEof);
+          if( DOCID_CMP(a[i].iDocid, iMax)>0 ){
+            iMax = a[i].iDocid;
+            i = 0;
+          }
+        }
+      }
+
+      /* Check if the current entries really are a phrase match */
+      if( bEof==0 ){
+        int nList = 0;
+        int nByte = a[p->nToken-1].nList;
+        char *aDoclist = sqlite3_malloc64((i64)nByte+FTS3_BUFFER_PADDING);
+        if( !aDoclist ) return SQLITE_NOMEM;
+        memcpy(aDoclist, a[p->nToken-1].pList, nByte+1);
+        memset(&aDoclist[nByte], 0, FTS3_BUFFER_PADDING);
+
+        for(i=0; i<(p->nToken-1); i++){
+          if( a[i].bIgnore==0 ){
+            char *pL = a[i].pList;
+            char *pR = aDoclist;
+            char *pOut = aDoclist;
+            int nDist = p->nToken-1-i;
+            int res = fts3PoslistPhraseMerge(&pOut, nDist, 0, 1, &pL, &pR);
+            if( res==0 ) break;
+            nList = (int)(pOut - aDoclist);
+          }
+        }
+        if( i==(p->nToken-1) ){
+          pDL->iDocid = iMax;
+          pDL->pList = aDoclist;
+          pDL->nList = nList;
+          pDL->bFreeList = 1;
+          break;
+        }
+        sqlite3_free(aDoclist);
+      }
+    }
+  }
+
+  *pbEof = bEof;
+  return rc;
+}
+
+/*
+** Attempt to move the phrase iterator to point to the next matching docid.
+** If an error occurs, return an SQLite error code. Otherwise, return
+** SQLITE_OK.
+**
+** If there is no "next" entry and no error occurs, then *pbEof is set to
+** 1 before returning. Otherwise, if no error occurs and the iterator is
+** successfully advanced, *pbEof is set to 0.
+*/
+static int fts3EvalPhraseNext(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Phrase *p,                  /* Phrase object to advance to next docid */
+  u8 *pbEof                       /* OUT: Set to 1 if EOF */
+){
+  int rc = SQLITE_OK;
+  Fts3Doclist *pDL = &p->doclist;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+
+  if( p->bIncr ){
+    rc = fts3EvalIncrPhraseNext(pCsr, p, pbEof);
+  }else if( pCsr->bDesc!=pTab->bDescIdx && pDL->nAll ){
+    sqlite3Fts3DoclistPrev(pTab->bDescIdx, pDL->aAll, pDL->nAll,
+        &pDL->pNextDocid, &pDL->iDocid, &pDL->nList, pbEof
+    );
+    pDL->pList = pDL->pNextDocid;
+  }else{
+    fts3EvalDlPhraseNext(pTab, pDL, pbEof);
+  }
+
+  return rc;
+}
+
+/*
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, fts3EvalPhraseStart() is called on all phrases within the
+** expression. Also the Fts3Expr.bDeferred variable is set to true for any
+** expressions for which all descendent tokens are deferred.
+**
+** If parameter bOptOk is zero, then it is guaranteed that the
+** Fts3Phrase.doclist.aAll/nAll variables contain the entire doclist for
+** each phrase in the expression (subject to deferred token processing).
+** Or, if bOptOk is non-zero, then one or more tokens within the expression
+** may be loaded incrementally, meaning doclist.aAll/nAll is not available.
+**
+** If an error occurs within this function, *pRc is set to an SQLite error
+** code before returning.
+*/
+static void fts3EvalStartReaders(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pExpr,                /* Expression to initialize phrases in */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( pExpr && SQLITE_OK==*pRc ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      int nToken = pExpr->pPhrase->nToken;
+      if( nToken ){
+        int i;
+        for(i=0; i<nToken; i++){
+          if( pExpr->pPhrase->aToken[i].pDeferred==0 ) break;
+        }
+        pExpr->bDeferred = (i==nToken);
+      }
+      *pRc = fts3EvalPhraseStart(pCsr, 1, pExpr->pPhrase);
+    }else{
+      fts3EvalStartReaders(pCsr, pExpr->pLeft, pRc);
+      fts3EvalStartReaders(pCsr, pExpr->pRight, pRc);
+      pExpr->bDeferred = (pExpr->pLeft->bDeferred && pExpr->pRight->bDeferred);
+    }
+  }
+}
+
+/*
+** An array of the following structures is assembled as part of the process
+** of selecting tokens to defer before the query starts executing (as part
+** of the xFilter() method). There is one element in the array for each
+** token in the FTS expression.
+**
+** Tokens are divided into AND/NEAR clusters. All tokens in a cluster belong
+** to phrases that are connected only by AND and NEAR operators (not OR or
+** NOT). When determining tokens to defer, each AND/NEAR cluster is considered
+** separately. The root of a tokens AND/NEAR cluster is stored in
+** Fts3TokenAndCost.pRoot.
+*/
+typedef struct Fts3TokenAndCost Fts3TokenAndCost;
+struct Fts3TokenAndCost {
+  Fts3Phrase *pPhrase;            /* The phrase the token belongs to */
+  int iToken;                     /* Position of token in phrase */
+  Fts3PhraseToken *pToken;        /* The token itself */
+  Fts3Expr *pRoot;                /* Root of NEAR/AND cluster */
+  int nOvfl;                      /* Number of overflow pages to load doclist */
+  int iCol;                       /* The column the token must match */
+};
+
+/*
+** This function is used to populate an allocated Fts3TokenAndCost array.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, if an error occurs during execution, *pRc is set to an
+** SQLite error code.
+*/
+static void fts3EvalTokenCosts(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pRoot,                /* Root of current AND/NEAR cluster */
+  Fts3Expr *pExpr,                /* Expression to consider */
+  Fts3TokenAndCost **ppTC,        /* Write new entries to *(*ppTC)++ */
+  Fts3Expr ***ppOr,               /* Write new OR root to *(*ppOr)++ */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( *pRc==SQLITE_OK ){
+    if( pExpr->eType==FTSQUERY_PHRASE ){
+      Fts3Phrase *pPhrase = pExpr->pPhrase;
+      int i;
+      for(i=0; *pRc==SQLITE_OK && i<pPhrase->nToken; i++){
+        Fts3TokenAndCost *pTC = (*ppTC)++;
+        pTC->pPhrase = pPhrase;
+        pTC->iToken = i;
+        pTC->pRoot = pRoot;
+        pTC->pToken = &pPhrase->aToken[i];
+        pTC->iCol = pPhrase->iColumn;
+        *pRc = sqlite3Fts3MsrOvfl(pCsr, pTC->pToken->pSegcsr, &pTC->nOvfl);
+      }
+    }else if( pExpr->eType!=FTSQUERY_NOT ){
+      assert( pExpr->eType==FTSQUERY_OR
+           || pExpr->eType==FTSQUERY_AND
+           || pExpr->eType==FTSQUERY_NEAR
+      );
+      assert( pExpr->pLeft && pExpr->pRight );
+      if( pExpr->eType==FTSQUERY_OR ){
+        pRoot = pExpr->pLeft;
+        **ppOr = pRoot;
+        (*ppOr)++;
+      }
+      fts3EvalTokenCosts(pCsr, pRoot, pExpr->pLeft, ppTC, ppOr, pRc);
+      if( pExpr->eType==FTSQUERY_OR ){
+        pRoot = pExpr->pRight;
+        **ppOr = pRoot;
+        (*ppOr)++;
+      }
+      fts3EvalTokenCosts(pCsr, pRoot, pExpr->pRight, ppTC, ppOr, pRc);
+    }
+  }
+}
+
+/*
+** Determine the average document (row) size in pages. If successful,
+** write this value to *pnPage and return SQLITE_OK. Otherwise, return
+** an SQLite error code.
+**
+** The average document size in pages is calculated by first calculating
+** determining the average size in bytes, B. If B is less than the amount
+** of data that will fit on a single leaf page of an intkey table in
+** this database, then the average docsize is 1. Otherwise, it is 1 plus
+** the number of overflow pages consumed by a record B bytes in size.
+*/
+static int fts3EvalAverageDocsize(Fts3Cursor *pCsr, int *pnPage){
+  int rc = SQLITE_OK;
+  if( pCsr->nRowAvg==0 ){
+    /* The average document size, which is required to calculate the cost
+    ** of each doclist, has not yet been determined. Read the required
+    ** data from the %_stat table to calculate it.
+    **
+    ** Entry 0 of the %_stat table is a blob containing (nCol+1) FTS3
+    ** varints, where nCol is the number of columns in the FTS3 table.
+    ** The first varint is the number of documents currently stored in
+    ** the table. The following nCol varints contain the total amount of
+    ** data stored in all rows of each column of the table, from left
+    ** to right.
+    */
+    Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
+    sqlite3_stmt *pStmt;
+    sqlite3_int64 nDoc = 0;
+    sqlite3_int64 nByte = 0;
+    const char *pEnd;
+    const char *a;
+
+    rc = sqlite3Fts3SelectDoctotal(p, &pStmt);
+    if( rc!=SQLITE_OK ) return rc;
+    a = sqlite3_column_blob(pStmt, 0);
+    testcase( a==0 );  /* If %_stat.value set to X'' */
+    if( a ){
+      pEnd = &a[sqlite3_column_bytes(pStmt, 0)];
+      a += sqlite3Fts3GetVarintBounded(a, pEnd, &nDoc);
+      while( a<pEnd ){
+        a += sqlite3Fts3GetVarintBounded(a, pEnd, &nByte);
+      }
+    }
+    if( nDoc==0 || nByte==0 ){
+      sqlite3_reset(pStmt);
+      return FTS_CORRUPT_VTAB;
+    }
+
+    pCsr->nDoc = nDoc;
+    pCsr->nRowAvg = (int)(((nByte / nDoc) + p->nPgsz) / p->nPgsz);
+    assert( pCsr->nRowAvg>0 );
+    rc = sqlite3_reset(pStmt);
+  }
+
+  *pnPage = pCsr->nRowAvg;
+  return rc;
+}
+
+/*
+** This function is called to select the tokens (if any) that will be
+** deferred. The array aTC[] has already been populated when this is
+** called.
+**
+** This function is called once for each AND/NEAR cluster in the
+** expression. Each invocation determines which tokens to defer within
+** the cluster with root node pRoot. See comments above the definition
+** of struct Fts3TokenAndCost for more details.
+**
+** If no error occurs, SQLITE_OK is returned and sqlite3Fts3DeferToken()
+** called on each token to defer. Otherwise, an SQLite error code is
+** returned.
+*/
+static int fts3EvalSelectDeferred(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pRoot,                /* Consider tokens with this root node */
+  Fts3TokenAndCost *aTC,          /* Array of expression tokens and costs */
+  int nTC                         /* Number of entries in aTC[] */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int nDocSize = 0;               /* Number of pages per doc loaded */
+  int rc = SQLITE_OK;             /* Return code */
+  int ii;                         /* Iterator variable for various purposes */
+  int nOvfl = 0;                  /* Total overflow pages used by doclists */
+  int nToken = 0;                 /* Total number of tokens in cluster */
+
+  int nMinEst = 0;                /* The minimum count for any phrase so far. */
+  int nLoad4 = 1;                 /* (Phrases that will be loaded)^4. */
+
+  /* Tokens are never deferred for FTS tables created using the content=xxx
+  ** option. The reason being that it is not guaranteed that the content
+  ** table actually contains the same data as the index. To prevent this from
+  ** causing any problems, the deferred token optimization is completely
+  ** disabled for content=xxx tables. */
+  if( pTab->zContentTbl ){
+    return SQLITE_OK;
+  }
+
+  /* Count the tokens in this AND/NEAR cluster. If none of the doclists
+  ** associated with the tokens spill onto overflow pages, or if there is
+  ** only 1 token, exit early. No tokens to defer in this case. */
+  for(ii=0; ii<nTC; ii++){
+    if( aTC[ii].pRoot==pRoot ){
+      nOvfl += aTC[ii].nOvfl;
+      nToken++;
+    }
+  }
+  if( nOvfl==0 || nToken<2 ) return SQLITE_OK;
+
+  /* Obtain the average docsize (in pages). */
+  rc = fts3EvalAverageDocsize(pCsr, &nDocSize);
+  assert( rc!=SQLITE_OK || nDocSize>0 );
+
+
+  /* Iterate through all tokens in this AND/NEAR cluster, in ascending order
+  ** of the number of overflow pages that will be loaded by the pager layer
+  ** to retrieve the entire doclist for the token from the full-text index.
+  ** Load the doclists for tokens that are either:
+  **
+  **   a. The cheapest token in the entire query (i.e. the one visited by the
+  **      first iteration of this loop), or
+  **
+  **   b. Part of a multi-token phrase.
+  **
+  ** After each token doclist is loaded, merge it with the others from the
+  ** same phrase and count the number of documents that the merged doclist
+  ** contains. Set variable "nMinEst" to the smallest number of documents in
+  ** any phrase doclist for which 1 or more token doclists have been loaded.
+  ** Let nOther be the number of other phrases for which it is certain that
+  ** one or more tokens will not be deferred.
+  **
+  ** Then, for each token, defer it if loading the doclist would result in
+  ** loading N or more overflow pages into memory, where N is computed as:
+  **
+  **    (nMinEst + 4^nOther - 1) / (4^nOther)
+  */
+  for(ii=0; ii<nToken && rc==SQLITE_OK; ii++){
+    int iTC;                      /* Used to iterate through aTC[] array. */
+    Fts3TokenAndCost *pTC = 0;    /* Set to cheapest remaining token. */
+
+    /* Set pTC to point to the cheapest remaining token. */
+    for(iTC=0; iTC<nTC; iTC++){
+      if( aTC[iTC].pToken && aTC[iTC].pRoot==pRoot
+       && (!pTC || aTC[iTC].nOvfl<pTC->nOvfl)
+      ){
+        pTC = &aTC[iTC];
+      }
+    }
+    assert( pTC );
+
+    if( ii && pTC->nOvfl>=((nMinEst+(nLoad4/4)-1)/(nLoad4/4))*nDocSize ){
+      /* The number of overflow pages to load for this (and therefore all
+      ** subsequent) tokens is greater than the estimated number of pages
+      ** that will be loaded if all subsequent tokens are deferred.
+      */
+      Fts3PhraseToken *pToken = pTC->pToken;
+      rc = sqlite3Fts3DeferToken(pCsr, pToken, pTC->iCol);
+      fts3SegReaderCursorFree(pToken->pSegcsr);
+      pToken->pSegcsr = 0;
+    }else{
+      /* Set nLoad4 to the value of (4^nOther) for the next iteration of the
+      ** for-loop. Except, limit the value to 2^24 to prevent it from
+      ** overflowing the 32-bit integer it is stored in. */
+      if( ii<12 ) nLoad4 = nLoad4*4;
+
+      if( ii==0 || (pTC->pPhrase->nToken>1 && ii!=nToken-1) ){
+        /* Either this is the cheapest token in the entire query, or it is
+        ** part of a multi-token phrase. Either way, the entire doclist will
+        ** (eventually) be loaded into memory. It may as well be now. */
+        Fts3PhraseToken *pToken = pTC->pToken;
+        int nList = 0;
+        char *pList = 0;
+        rc = fts3TermSelect(pTab, pToken, pTC->iCol, &nList, &pList);
+        assert( rc==SQLITE_OK || pList==0 );
+        if( rc==SQLITE_OK ){
+          rc = fts3EvalPhraseMergeToken(
+              pTab, pTC->pPhrase, pTC->iToken,pList,nList
+          );
+        }
+        if( rc==SQLITE_OK ){
+          int nCount;
+          nCount = fts3DoclistCountDocids(
+              pTC->pPhrase->doclist.aAll, pTC->pPhrase->doclist.nAll
+          );
+          if( ii==0 || nCount<nMinEst ) nMinEst = nCount;
+        }
+      }
+    }
+    pTC->pToken = 0;
+  }
+
+  return rc;
+}
+
+/*
+** This function is called from within the xFilter method. It initializes
+** the full-text query currently stored in pCsr->pExpr. To iterate through
+** the results of a query, the caller does:
+**
+**    fts3EvalStart(pCsr);
+**    while( 1 ){
+**      fts3EvalNext(pCsr);
+**      if( pCsr->bEof ) break;
+**      ... return row pCsr->iPrevId to the caller ...
+**    }
+*/
+static int fts3EvalStart(Fts3Cursor *pCsr){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int nToken = 0;
+  int nOr = 0;
+
+  /* Allocate a MultiSegReader for each token in the expression. */
+  fts3EvalAllocateReaders(pCsr, pCsr->pExpr, &nToken, &nOr, &rc);
+
+  /* Determine which, if any, tokens in the expression should be deferred. */
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+  if( rc==SQLITE_OK && nToken>1 && pTab->bFts4 ){
+    Fts3TokenAndCost *aTC;
+    aTC = (Fts3TokenAndCost *)sqlite3_malloc64(
+        sizeof(Fts3TokenAndCost) * nToken
+      + sizeof(Fts3Expr *) * nOr * 2
+    );
+
+    if( !aTC ){
+      rc = SQLITE_NOMEM;
+    }else{
+      Fts3Expr **apOr = (Fts3Expr **)&aTC[nToken];
+      int ii;
+      Fts3TokenAndCost *pTC = aTC;
+      Fts3Expr **ppOr = apOr;
+
+      fts3EvalTokenCosts(pCsr, 0, pCsr->pExpr, &pTC, &ppOr, &rc);
+      nToken = (int)(pTC-aTC);
+      nOr = (int)(ppOr-apOr);
+
+      if( rc==SQLITE_OK ){
+        rc = fts3EvalSelectDeferred(pCsr, 0, aTC, nToken);
+        for(ii=0; rc==SQLITE_OK && ii<nOr; ii++){
+          rc = fts3EvalSelectDeferred(pCsr, apOr[ii], aTC, nToken);
+        }
+      }
+
+      sqlite3_free(aTC);
+    }
+  }
+#endif
+
+  fts3EvalStartReaders(pCsr, pCsr->pExpr, &rc);
+  return rc;
+}
+
+/*
+** Invalidate the current position list for phrase pPhrase.
+*/
+static void fts3EvalInvalidatePoslist(Fts3Phrase *pPhrase){
+  if( pPhrase->doclist.bFreeList ){
+    sqlite3_free(pPhrase->doclist.pList);
+  }
+  pPhrase->doclist.pList = 0;
+  pPhrase->doclist.nList = 0;
+  pPhrase->doclist.bFreeList = 0;
+}
+
+/*
+** This function is called to edit the position list associated with
+** the phrase object passed as the fifth argument according to a NEAR
+** condition. For example:
+**
+**     abc NEAR/5 "def ghi"
+**
+** Parameter nNear is passed the NEAR distance of the expression (5 in
+** the example above). When this function is called, *paPoslist points to
+** the position list, and *pnToken is the number of phrase tokens in the
+** phrase on the other side of the NEAR operator to pPhrase. For example,
+** if pPhrase refers to the "def ghi" phrase, then *paPoslist points to
+** the position list associated with phrase "abc".
+**
+** All positions in the pPhrase position list that are not sufficiently
+** close to a position in the *paPoslist position list are removed. If this
+** leaves 0 positions, zero is returned. Otherwise, non-zero.
+**
+** Before returning, *paPoslist is set to point to the position lsit
+** associated with pPhrase. And *pnToken is set to the number of tokens in
+** pPhrase.
+*/
+static int fts3EvalNearTrim(
+  int nNear,                      /* NEAR distance. As in "NEAR/nNear". */
+  char *aTmp,                     /* Temporary space to use */
+  char **paPoslist,               /* IN/OUT: Position list */
+  int *pnToken,                   /* IN/OUT: Tokens in phrase of *paPoslist */
+  Fts3Phrase *pPhrase             /* The phrase object to trim the doclist of */
+){
+  int nParam1 = nNear + pPhrase->nToken;
+  int nParam2 = nNear + *pnToken;
+  int nNew;
+  char *p2;
+  char *pOut;
+  int res;
+
+  assert( pPhrase->doclist.pList );
+
+  p2 = pOut = pPhrase->doclist.pList;
+  res = fts3PoslistNearMerge(
+    &pOut, aTmp, nParam1, nParam2, paPoslist, &p2
+  );
+  if( res ){
+    nNew = (int)(pOut - pPhrase->doclist.pList) - 1;
+    assert_fts3_nc( nNew<=pPhrase->doclist.nList && nNew>0 );
+    if( nNew>=0 && nNew<=pPhrase->doclist.nList ){
+      assert( pPhrase->doclist.pList[nNew]=='\0' );
+      memset(&pPhrase->doclist.pList[nNew], 0, pPhrase->doclist.nList - nNew);
+      pPhrase->doclist.nList = nNew;
+    }
+    *paPoslist = pPhrase->doclist.pList;
+    *pnToken = pPhrase->nToken;
+  }
+
+  return res;
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is called.
+** Otherwise, it advances the expression passed as the second argument to
+** point to the next matching row in the database. Expressions iterate through
+** matching rows in docid order. Ascending order if Fts3Cursor.bDesc is zero,
+** or descending if it is non-zero.
+**
+** If an error occurs, *pRc is set to an SQLite error code. Otherwise, if
+** successful, the following variables in pExpr are set:
+**
+**   Fts3Expr.bEof                (non-zero if EOF - there is no next row)
+**   Fts3Expr.iDocid              (valid if bEof==0. The docid of the next row)
+**
+** If the expression is of type FTSQUERY_PHRASE, and the expression is not
+** at EOF, then the following variables are populated with the position list
+** for the phrase for the visited row:
+**
+**   FTs3Expr.pPhrase->doclist.nList        (length of pList in bytes)
+**   FTs3Expr.pPhrase->doclist.pList        (pointer to position list)
+**
+** It says above that this function advances the expression to the next
+** matching row. This is usually true, but there are the following exceptions:
+**
+**   1. Deferred tokens are not taken into account. If a phrase consists
+**      entirely of deferred tokens, it is assumed to match every row in
+**      the db. In this case the position-list is not populated at all.
+**
+**      Or, if a phrase contains one or more deferred tokens and one or
+**      more non-deferred tokens, then the expression is advanced to the
+**      next possible match, considering only non-deferred tokens. In other
+**      words, if the phrase is "A B C", and "B" is deferred, the expression
+**      is advanced to the next row that contains an instance of "A * C",
+**      where "*" may match any single token. The position list in this case
+**      is populated as for "A * C" before returning.
+**
+**   2. NEAR is treated as AND. If the expression is "x NEAR y", it is
+**      advanced to point to the next row that matches "x AND y".
+**
+** See sqlite3Fts3EvalTestDeferred() for details on testing if a row is
+** really a match, taking into account deferred tokens and NEAR operators.
+*/
+static void fts3EvalNextRow(
+  Fts3Cursor *pCsr,               /* FTS Cursor handle */
+  Fts3Expr *pExpr,                /* Expr. to advance to next matching row */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( *pRc==SQLITE_OK && pExpr->bEof==0 ){
+    int bDescDoclist = pCsr->bDesc;         /* Used by DOCID_CMP() macro */
+    pExpr->bStart = 1;
+
+    switch( pExpr->eType ){
+      case FTSQUERY_NEAR:
+      case FTSQUERY_AND: {
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+        assert( !pLeft->bDeferred || !pRight->bDeferred );
+
+        if( pLeft->bDeferred ){
+          /* LHS is entirely deferred. So we assume it matches every row.
+          ** Advance the RHS iterator to find the next row visited. */
+          fts3EvalNextRow(pCsr, pRight, pRc);
+          pExpr->iDocid = pRight->iDocid;
+          pExpr->bEof = pRight->bEof;
+        }else if( pRight->bDeferred ){
+          /* RHS is entirely deferred. So we assume it matches every row.
+          ** Advance the LHS iterator to find the next row visited. */
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+          pExpr->iDocid = pLeft->iDocid;
+          pExpr->bEof = pLeft->bEof;
+        }else{
+          /* Neither the RHS or LHS are deferred. */
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+          fts3EvalNextRow(pCsr, pRight, pRc);
+          while( !pLeft->bEof && !pRight->bEof && *pRc==SQLITE_OK ){
+            sqlite3_int64 iDiff = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
+            if( iDiff==0 ) break;
+            if( iDiff<0 ){
+              fts3EvalNextRow(pCsr, pLeft, pRc);
+            }else{
+              fts3EvalNextRow(pCsr, pRight, pRc);
+            }
+          }
+          pExpr->iDocid = pLeft->iDocid;
+          pExpr->bEof = (pLeft->bEof || pRight->bEof);
+          if( pExpr->eType==FTSQUERY_NEAR && pExpr->bEof ){
+            assert( pRight->eType==FTSQUERY_PHRASE );
+            if( pRight->pPhrase->doclist.aAll ){
+              Fts3Doclist *pDl = &pRight->pPhrase->doclist;
+              while( *pRc==SQLITE_OK && pRight->bEof==0 ){
+                memset(pDl->pList, 0, pDl->nList);
+                fts3EvalNextRow(pCsr, pRight, pRc);
+              }
+            }
+            if( pLeft->pPhrase && pLeft->pPhrase->doclist.aAll ){
+              Fts3Doclist *pDl = &pLeft->pPhrase->doclist;
+              while( *pRc==SQLITE_OK && pLeft->bEof==0 ){
+                memset(pDl->pList, 0, pDl->nList);
+                fts3EvalNextRow(pCsr, pLeft, pRc);
+              }
+            }
+            pRight->bEof = pLeft->bEof = 1;
+          }
+        }
+        break;
+      }
+
+      case FTSQUERY_OR: {
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+        sqlite3_int64 iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
+
+        assert_fts3_nc( pLeft->bStart || pLeft->iDocid==pRight->iDocid );
+        assert_fts3_nc( pRight->bStart || pLeft->iDocid==pRight->iDocid );
+
+        if( pRight->bEof || (pLeft->bEof==0 && iCmp<0) ){
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+        }else if( pLeft->bEof || iCmp>0 ){
+          fts3EvalNextRow(pCsr, pRight, pRc);
+        }else{
+          fts3EvalNextRow(pCsr, pLeft, pRc);
+          fts3EvalNextRow(pCsr, pRight, pRc);
+        }
+
+        pExpr->bEof = (pLeft->bEof && pRight->bEof);
+        iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
+        if( pRight->bEof || (pLeft->bEof==0 &&  iCmp<0) ){
+          pExpr->iDocid = pLeft->iDocid;
+        }else{
+          pExpr->iDocid = pRight->iDocid;
+        }
+
+        break;
+      }
+
+      case FTSQUERY_NOT: {
+        Fts3Expr *pLeft = pExpr->pLeft;
+        Fts3Expr *pRight = pExpr->pRight;
+
+        if( pRight->bStart==0 ){
+          fts3EvalNextRow(pCsr, pRight, pRc);
+          assert( *pRc!=SQLITE_OK || pRight->bStart );
+        }
+
+        fts3EvalNextRow(pCsr, pLeft, pRc);
+        if( pLeft->bEof==0 ){
+          while( !*pRc
+              && !pRight->bEof
+              && DOCID_CMP(pLeft->iDocid, pRight->iDocid)>0
+          ){
+            fts3EvalNextRow(pCsr, pRight, pRc);
+          }
+        }
+        pExpr->iDocid = pLeft->iDocid;
+        pExpr->bEof = pLeft->bEof;
+        break;
+      }
+
+      default: {
+        Fts3Phrase *pPhrase = pExpr->pPhrase;
+        fts3EvalInvalidatePoslist(pPhrase);
+        *pRc = fts3EvalPhraseNext(pCsr, pPhrase, &pExpr->bEof);
+        pExpr->iDocid = pPhrase->doclist.iDocid;
+        break;
+      }
+    }
+  }
+}
+
+/*
+** If *pRc is not SQLITE_OK, or if pExpr is not the root node of a NEAR
+** cluster, then this function returns 1 immediately.
+**
+** Otherwise, it checks if the current row really does match the NEAR
+** expression, using the data currently stored in the position lists
+** (Fts3Expr->pPhrase.doclist.pList/nList) for each phrase in the expression.
+**
+** If the current row is a match, the position list associated with each
+** phrase in the NEAR expression is edited in place to contain only those
+** phrase instances sufficiently close to their peers to satisfy all NEAR
+** constraints. In this case it returns 1. If the NEAR expression does not
+** match the current row, 0 is returned. The position lists may or may not
+** be edited if 0 is returned.
+*/
+static int fts3EvalNearTest(Fts3Expr *pExpr, int *pRc){
+  int res = 1;
+
+  /* The following block runs if pExpr is the root of a NEAR query.
+  ** For example, the query:
+  **
+  **         "w" NEAR "x" NEAR "y" NEAR "z"
+  **
+  ** which is represented in tree form as:
+  **
+  **                               |
+  **                          +--NEAR--+      <-- root of NEAR query
+  **                          |        |
+  **                     +--NEAR--+   "z"
+  **                     |        |
+  **                +--NEAR--+   "y"
+  **                |        |
+  **               "w"      "x"
+  **
+  ** The right-hand child of a NEAR node is always a phrase. The
+  ** left-hand child may be either a phrase or a NEAR node. There are
+  ** no exceptions to this - it's the way the parser in fts3_expr.c works.
+  */
+  if( *pRc==SQLITE_OK
+   && pExpr->eType==FTSQUERY_NEAR
+   && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
+  ){
+    Fts3Expr *p;
+    sqlite3_int64 nTmp = 0;       /* Bytes of temp space */
+    char *aTmp;                   /* Temp space for PoslistNearMerge() */
+
+    /* Allocate temporary working space. */
+    for(p=pExpr; p->pLeft; p=p->pLeft){
+      assert( p->pRight->pPhrase->doclist.nList>0 );
+      nTmp += p->pRight->pPhrase->doclist.nList;
+    }
+    nTmp += p->pPhrase->doclist.nList;
+    aTmp = sqlite3_malloc64(nTmp*2 + FTS3_VARINT_MAX);
+    if( !aTmp ){
+      *pRc = SQLITE_NOMEM;
+      res = 0;
+    }else{
+      char *aPoslist = p->pPhrase->doclist.pList;
+      int nToken = p->pPhrase->nToken;
+
+      for(p=p->pParent;res && p && p->eType==FTSQUERY_NEAR; p=p->pParent){
+        Fts3Phrase *pPhrase = p->pRight->pPhrase;
+        int nNear = p->nNear;
+        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
+      }
+
+      aPoslist = pExpr->pRight->pPhrase->doclist.pList;
+      nToken = pExpr->pRight->pPhrase->nToken;
+      for(p=pExpr->pLeft; p && res; p=p->pLeft){
+        int nNear;
+        Fts3Phrase *pPhrase;
+        assert( p->pParent && p->pParent->pLeft==p );
+        nNear = p->pParent->nNear;
+        pPhrase = (
+            p->eType==FTSQUERY_NEAR ? p->pRight->pPhrase : p->pPhrase
+        );
+        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
+      }
+    }
+
+    sqlite3_free(aTmp);
+  }
+
+  return res;
+}
+
+/*
+** This function is a helper function for sqlite3Fts3EvalTestDeferred().
+** Assuming no error occurs or has occurred, It returns non-zero if the
+** expression passed as the second argument matches the row that pCsr
+** currently points to, or zero if it does not.
+**
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** If an error occurs during execution of this function, *pRc is set to
+** the appropriate SQLite error code. In this case the returned value is
+** undefined.
+*/
+static int fts3EvalTestExpr(
+  Fts3Cursor *pCsr,               /* FTS cursor handle */
+  Fts3Expr *pExpr,                /* Expr to test. May or may not be root. */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  int bHit = 1;                   /* Return value */
+  if( *pRc==SQLITE_OK ){
+    switch( pExpr->eType ){
+      case FTSQUERY_NEAR:
+      case FTSQUERY_AND:
+        bHit = (
+            fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc)
+         && fts3EvalTestExpr(pCsr, pExpr->pRight, pRc)
+         && fts3EvalNearTest(pExpr, pRc)
+        );
+
+        /* If the NEAR expression does not match any rows, zero the doclist for
+        ** all phrases involved in the NEAR. This is because the snippet(),
+        ** offsets() and matchinfo() functions are not supposed to recognize
+        ** any instances of phrases that are part of unmatched NEAR queries.
+        ** For example if this expression:
+        **
+        **    ... MATCH 'a OR (b NEAR c)'
+        **
+        ** is matched against a row containing:
+        **
+        **        'a b d e'
+        **
+        ** then any snippet() should ony highlight the "a" term, not the "b"
+        ** (as "b" is part of a non-matching NEAR clause).
+        */
+        if( bHit==0
+         && pExpr->eType==FTSQUERY_NEAR
+         && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
+        ){
+          Fts3Expr *p;
+          for(p=pExpr; p->pPhrase==0; p=p->pLeft){
+            if( p->pRight->iDocid==pCsr->iPrevId ){
+              fts3EvalInvalidatePoslist(p->pRight->pPhrase);
+            }
+          }
+          if( p->iDocid==pCsr->iPrevId ){
+            fts3EvalInvalidatePoslist(p->pPhrase);
+          }
+        }
+
+        break;
+
+      case FTSQUERY_OR: {
+        int bHit1 = fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc);
+        int bHit2 = fts3EvalTestExpr(pCsr, pExpr->pRight, pRc);
+        bHit = bHit1 || bHit2;
+        break;
+      }
+
+      case FTSQUERY_NOT:
+        bHit = (
+            fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc)
+         && !fts3EvalTestExpr(pCsr, pExpr->pRight, pRc)
+        );
+        break;
+
+      default: {
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+        if( pCsr->pDeferred && (pExpr->bDeferred || (
+            pExpr->iDocid==pCsr->iPrevId && pExpr->pPhrase->doclist.pList
+        ))){
+          Fts3Phrase *pPhrase = pExpr->pPhrase;
+          if( pExpr->bDeferred ){
+            fts3EvalInvalidatePoslist(pPhrase);
+          }
+          *pRc = fts3EvalDeferredPhrase(pCsr, pPhrase);
+          bHit = (pPhrase->doclist.pList!=0);
+          pExpr->iDocid = pCsr->iPrevId;
+        }else
+#endif
+        {
+          bHit = (
+              pExpr->bEof==0 && pExpr->iDocid==pCsr->iPrevId
+           && pExpr->pPhrase->doclist.nList>0
+          );
+        }
+        break;
+      }
+    }
+  }
+  return bHit;
+}
+
+/*
+** This function is called as the second part of each xNext operation when
+** iterating through the results of a full-text query. At this point the
+** cursor points to a row that matches the query expression, with the
+** following caveats:
+**
+**   * Up until this point, "NEAR" operators in the expression have been
+**     treated as "AND".
+**
+**   * Deferred tokens have not yet been considered.
+**
+** If *pRc is not SQLITE_OK when this function is called, it immediately
+** returns 0. Otherwise, it tests whether or not after considering NEAR
+** operators and deferred tokens the current row is still a match for the
+** expression. It returns 1 if both of the following are true:
+**
+**   1. *pRc is SQLITE_OK when this function returns, and
+**
+**   2. After scanning the current FTS table row for the deferred tokens,
+**      it is determined that the row does *not* match the query.
+**
+** Or, if no error occurs and it seems the current row does match the FTS
+** query, return 0.
+*/
+SQLITE_PRIVATE int sqlite3Fts3EvalTestDeferred(Fts3Cursor *pCsr, int *pRc){
+  int rc = *pRc;
+  int bMiss = 0;
+  if( rc==SQLITE_OK ){
+
+    /* If there are one or more deferred tokens, load the current row into
+    ** memory and scan it to determine the position list for each deferred
+    ** token. Then, see if this row is really a match, considering deferred
+    ** tokens and NEAR operators (neither of which were taken into account
+    ** earlier, by fts3EvalNextRow()).
+    */
+    if( pCsr->pDeferred ){
+      rc = fts3CursorSeek(0, pCsr);
+      if( rc==SQLITE_OK ){
+        rc = sqlite3Fts3CacheDeferredDoclists(pCsr);
+      }
+    }
+    bMiss = (0==fts3EvalTestExpr(pCsr, pCsr->pExpr, &rc));
+
+    /* Free the position-lists accumulated for each deferred token above. */
+    sqlite3Fts3FreeDeferredDoclists(pCsr);
+    *pRc = rc;
+  }
+  return (rc==SQLITE_OK && bMiss);
+}
+
+/*
+** Advance to the next document that matches the FTS expression in
+** Fts3Cursor.pExpr.
+*/
+static int fts3EvalNext(Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;             /* Return Code */
+  Fts3Expr *pExpr = pCsr->pExpr;
+  assert( pCsr->isEof==0 );
+  if( pExpr==0 ){
+    pCsr->isEof = 1;
+  }else{
+    do {
+      if( pCsr->isRequireSeek==0 ){
+        sqlite3_reset(pCsr->pStmt);
+      }
+      assert( sqlite3_data_count(pCsr->pStmt)==0 );
+      fts3EvalNextRow(pCsr, pExpr, &rc);
+      pCsr->isEof = pExpr->bEof;
+      pCsr->isRequireSeek = 1;
+      pCsr->isMatchinfoNeeded = 1;
+      pCsr->iPrevId = pExpr->iDocid;
+    }while( pCsr->isEof==0 && sqlite3Fts3EvalTestDeferred(pCsr, &rc) );
+  }
+
+  /* Check if the cursor is past the end of the docid range specified
+  ** by Fts3Cursor.iMinDocid/iMaxDocid. If so, set the EOF flag.  */
+  if( rc==SQLITE_OK && (
+        (pCsr->bDesc==0 && pCsr->iPrevId>pCsr->iMaxDocid)
+     || (pCsr->bDesc!=0 && pCsr->iPrevId<pCsr->iMinDocid)
+  )){
+    pCsr->isEof = 1;
+  }
+
+  return rc;
+}
+
+/*
+** Restart interation for expression pExpr so that the next call to
+** fts3EvalNext() visits the first row. Do not allow incremental
+** loading or merging of phrase doclists for this iteration.
+**
+** If *pRc is other than SQLITE_OK when this function is called, it is
+** a no-op. If an error occurs within this function, *pRc is set to an
+** SQLite error code before returning.
+*/
+static void fts3EvalRestart(
+  Fts3Cursor *pCsr,
+  Fts3Expr *pExpr,
+  int *pRc
+){
+  if( pExpr && *pRc==SQLITE_OK ){
+    Fts3Phrase *pPhrase = pExpr->pPhrase;
+
+    if( pPhrase ){
+      fts3EvalInvalidatePoslist(pPhrase);
+      if( pPhrase->bIncr ){
+        int i;
+        for(i=0; i<pPhrase->nToken; i++){
+          Fts3PhraseToken *pToken = &pPhrase->aToken[i];
+          assert( pToken->pDeferred==0 );
+          if( pToken->pSegcsr ){
+            sqlite3Fts3MsrIncrRestart(pToken->pSegcsr);
+          }
+        }
+        *pRc = fts3EvalPhraseStart(pCsr, 0, pPhrase);
+      }
+      pPhrase->doclist.pNextDocid = 0;
+      pPhrase->doclist.iDocid = 0;
+      pPhrase->pOrPoslist = 0;
+    }
+
+    pExpr->iDocid = 0;
+    pExpr->bEof = 0;
+    pExpr->bStart = 0;
+
+    fts3EvalRestart(pCsr, pExpr->pLeft, pRc);
+    fts3EvalRestart(pCsr, pExpr->pRight, pRc);
+  }
+}
+
+/*
+** Expression node pExpr is an MSR phrase. This function restarts pExpr
+** so that it is a regular phrase query, not an MSR. SQLITE_OK is returned
+** if successful, or an SQLite error code otherwise.
+*/
+SQLITE_PRIVATE int sqlite3Fts3MsrCancel(Fts3Cursor *pCsr, Fts3Expr *pExpr){
+  int rc = SQLITE_OK;
+  if( pExpr->bEof==0 ){
+    i64 iDocid = pExpr->iDocid;
+    fts3EvalRestart(pCsr, pExpr, &rc);
+    while( rc==SQLITE_OK && pExpr->iDocid!=iDocid ){
+      fts3EvalNextRow(pCsr, pExpr, &rc);
+      if( pExpr->bEof ) rc = FTS_CORRUPT_VTAB;
+    }
+  }
+  return rc;
+}
+
+/*
+** After allocating the Fts3Expr.aMI[] array for each phrase in the
+** expression rooted at pExpr, the cursor iterates through all rows matched
+** by pExpr, calling this function for each row. This function increments
+** the values in Fts3Expr.aMI[] according to the position-list currently
+** found in Fts3Expr.pPhrase->doclist.pList for each of the phrase
+** expression nodes.
+*/
+static void fts3EvalUpdateCounts(Fts3Expr *pExpr, int nCol){
+  if( pExpr ){
+    Fts3Phrase *pPhrase = pExpr->pPhrase;
+    if( pPhrase && pPhrase->doclist.pList ){
+      int iCol = 0;
+      char *p = pPhrase->doclist.pList;
+
+      do{
+        u8 c = 0;
+        int iCnt = 0;
+        while( 0xFE & (*p | c) ){
+          if( (c&0x80)==0 ) iCnt++;
+          c = *p++ & 0x80;
+        }
+
+        /* aMI[iCol*3 + 1] = Number of occurrences
+        ** aMI[iCol*3 + 2] = Number of rows containing at least one instance
+        */
+        pExpr->aMI[iCol*3 + 1] += iCnt;
+        pExpr->aMI[iCol*3 + 2] += (iCnt>0);
+        if( *p==0x00 ) break;
+        p++;
+        p += fts3GetVarint32(p, &iCol);
+      }while( iCol<nCol );
+    }
+
+    fts3EvalUpdateCounts(pExpr->pLeft, nCol);
+    fts3EvalUpdateCounts(pExpr->pRight, nCol);
+  }
+}
+
+/*
+** This is an sqlite3Fts3ExprIterate() callback. If the Fts3Expr.aMI[] array
+** has not yet been allocated, allocate and zero it. Otherwise, just zero
+** it.
+*/
+static int fts3AllocateMSI(Fts3Expr *pExpr, int iPhrase, void *pCtx){
+  Fts3Table *pTab = (Fts3Table*)pCtx;
+  UNUSED_PARAMETER(iPhrase);
+  if( pExpr->aMI==0 ){
+    pExpr->aMI = (u32 *)sqlite3_malloc64(pTab->nColumn * 3 * sizeof(u32));
+    if( pExpr->aMI==0 ) return SQLITE_NOMEM;
+  }
+  memset(pExpr->aMI, 0, pTab->nColumn * 3 * sizeof(u32));
+  return SQLITE_OK;
+}
+
+/*
+** Expression pExpr must be of type FTSQUERY_PHRASE.
+**
+** If it is not already allocated and populated, this function allocates and
+** populates the Fts3Expr.aMI[] array for expression pExpr. If pExpr is part
+** of a NEAR expression, then it also allocates and populates the same array
+** for all other phrases that are part of the NEAR expression.
+**
+** SQLITE_OK is returned if the aMI[] array is successfully allocated and
+** populated. Otherwise, if an error occurs, an SQLite error code is returned.
+*/
+static int fts3EvalGatherStats(
+  Fts3Cursor *pCsr,               /* Cursor object */
+  Fts3Expr *pExpr                 /* FTSQUERY_PHRASE expression */
+){
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( pExpr->eType==FTSQUERY_PHRASE );
+  if( pExpr->aMI==0 ){
+    Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+    Fts3Expr *pRoot;                /* Root of NEAR expression */
+
+    sqlite3_int64 iPrevId = pCsr->iPrevId;
+    sqlite3_int64 iDocid;
+    u8 bEof;
+
+    /* Find the root of the NEAR expression */
+    pRoot = pExpr;
+    while( pRoot->pParent
+        && (pRoot->pParent->eType==FTSQUERY_NEAR || pRoot->bDeferred)
+    ){
+      pRoot = pRoot->pParent;
+    }
+    iDocid = pRoot->iDocid;
+    bEof = pRoot->bEof;
+    assert( pRoot->bStart );
+
+    /* Allocate space for the aMSI[] array of each FTSQUERY_PHRASE node */
+    rc = sqlite3Fts3ExprIterate(pRoot, fts3AllocateMSI, (void*)pTab);
+    if( rc!=SQLITE_OK ) return rc;
+    fts3EvalRestart(pCsr, pRoot, &rc);
+
+    while( pCsr->isEof==0 && rc==SQLITE_OK ){
+
+      do {
+        /* Ensure the %_content statement is reset. */
+        if( pCsr->isRequireSeek==0 ) sqlite3_reset(pCsr->pStmt);
+        assert( sqlite3_data_count(pCsr->pStmt)==0 );
+
+        /* Advance to the next document */
+        fts3EvalNextRow(pCsr, pRoot, &rc);
+        pCsr->isEof = pRoot->bEof;
+        pCsr->isRequireSeek = 1;
+        pCsr->isMatchinfoNeeded = 1;
+        pCsr->iPrevId = pRoot->iDocid;
+      }while( pCsr->isEof==0
+           && pRoot->eType==FTSQUERY_NEAR
+           && sqlite3Fts3EvalTestDeferred(pCsr, &rc)
+      );
+
+      if( rc==SQLITE_OK && pCsr->isEof==0 ){
+        fts3EvalUpdateCounts(pRoot, pTab->nColumn);
+      }
+    }
+
+    pCsr->isEof = 0;
+    pCsr->iPrevId = iPrevId;
+
+    if( bEof ){
+      pRoot->bEof = bEof;
+    }else{
+      /* Caution: pRoot may iterate through docids in ascending or descending
+      ** order. For this reason, even though it seems more defensive, the
+      ** do loop can not be written:
+      **
+      **   do {...} while( pRoot->iDocid<iDocid && rc==SQLITE_OK );
+      */
+      fts3EvalRestart(pCsr, pRoot, &rc);
+      do {
+        fts3EvalNextRow(pCsr, pRoot, &rc);
+        assert_fts3_nc( pRoot->bEof==0 );
+        if( pRoot->bEof ) rc = FTS_CORRUPT_VTAB;
+      }while( pRoot->iDocid!=iDocid && rc==SQLITE_OK );
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is used by the matchinfo() module to query a phrase
+** expression node for the following information:
+**
+**   1. The total number of occurrences of the phrase in each column of
+**      the FTS table (considering all rows), and
+**
+**   2. For each column, the number of rows in the table for which the
+**      column contains at least one instance of the phrase.
+**
+** If no error occurs, SQLITE_OK is returned and the values for each column
+** written into the array aiOut as follows:
+**
+**   aiOut[iCol*3 + 1] = Number of occurrences
+**   aiOut[iCol*3 + 2] = Number of rows containing at least one instance
+**
+** Caveats:
+**
+**   * If a phrase consists entirely of deferred tokens, then all output
+**     values are set to the number of documents in the table. In other
+**     words we assume that very common tokens occur exactly once in each
+**     column of each row of the table.
+**
+**   * If a phrase contains some deferred tokens (and some non-deferred
+**     tokens), count the potential occurrence identified by considering
+**     the non-deferred tokens instead of actual phrase occurrences.
+**
+**   * If the phrase is part of a NEAR expression, then only phrase instances
+**     that meet the NEAR constraint are included in the counts.
+*/
+SQLITE_PRIVATE int sqlite3Fts3EvalPhraseStats(
+  Fts3Cursor *pCsr,               /* FTS cursor handle */
+  Fts3Expr *pExpr,                /* Phrase expression */
+  u32 *aiOut                      /* Array to write results into (see above) */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int iCol;
+
+  if( pExpr->bDeferred && pExpr->pParent->eType!=FTSQUERY_NEAR ){
+    assert( pCsr->nDoc>0 );
+    for(iCol=0; iCol<pTab->nColumn; iCol++){
+      aiOut[iCol*3 + 1] = (u32)pCsr->nDoc;
+      aiOut[iCol*3 + 2] = (u32)pCsr->nDoc;
+    }
+  }else{
+    rc = fts3EvalGatherStats(pCsr, pExpr);
+    if( rc==SQLITE_OK ){
+      assert( pExpr->aMI );
+      for(iCol=0; iCol<pTab->nColumn; iCol++){
+        aiOut[iCol*3 + 1] = pExpr->aMI[iCol*3 + 1];
+        aiOut[iCol*3 + 2] = pExpr->aMI[iCol*3 + 2];
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The expression pExpr passed as the second argument to this function
+** must be of type FTSQUERY_PHRASE.
+**
+** The returned value is either NULL or a pointer to a buffer containing
+** a position-list indicating the occurrences of the phrase in column iCol
+** of the current row.
+**
+** More specifically, the returned buffer contains 1 varint for each
+** occurrence of the phrase in the column, stored using the normal (delta+2)
+** compression and is terminated by either an 0x01 or 0x00 byte. For example,
+** if the requested column contains "a b X c d X X" and the position-list
+** for 'X' is requested, the buffer returned may contain:
+**
+**     0x04 0x05 0x03 0x01   or   0x04 0x05 0x03 0x00
+**
+** This function works regardless of whether or not the phrase is deferred,
+** incremental, or neither.
+*/
+SQLITE_PRIVATE int sqlite3Fts3EvalPhrasePoslist(
+  Fts3Cursor *pCsr,               /* FTS3 cursor object */
+  Fts3Expr *pExpr,                /* Phrase to return doclist for */
+  int iCol,                       /* Column to return position list for */
+  char **ppOut                    /* OUT: Pointer to position list */
+){
+  Fts3Phrase *pPhrase = pExpr->pPhrase;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  char *pIter;
+  int iThis;
+  sqlite3_int64 iDocid;
+
+  /* If this phrase is applies specifically to some column other than
+  ** column iCol, return a NULL pointer.  */
+  *ppOut = 0;
+  assert( iCol>=0 && iCol<pTab->nColumn );
+  if( (pPhrase->iColumn<pTab->nColumn && pPhrase->iColumn!=iCol) ){
+    return SQLITE_OK;
+  }
+
+  iDocid = pExpr->iDocid;
+  pIter = pPhrase->doclist.pList;
+  if( iDocid!=pCsr->iPrevId || pExpr->bEof ){
+    int rc = SQLITE_OK;
+    int bDescDoclist = pTab->bDescIdx;      /* For DOCID_CMP macro */
+    int bOr = 0;
+    u8 bTreeEof = 0;
+    Fts3Expr *p;                  /* Used to iterate from pExpr to root */
+    Fts3Expr *pNear;              /* Most senior NEAR ancestor (or pExpr) */
+    Fts3Expr *pRun;               /* Closest non-deferred ancestor of pNear */
+    int bMatch;
+
+    /* Check if this phrase descends from an OR expression node. If not,
+    ** return NULL. Otherwise, the entry that corresponds to docid
+    ** pCsr->iPrevId may lie earlier in the doclist buffer. Or, if the
+    ** tree that the node is part of has been marked as EOF, but the node
+    ** itself is not EOF, then it may point to an earlier entry. */
+    pNear = pExpr;
+    for(p=pExpr->pParent; p; p=p->pParent){
+      if( p->eType==FTSQUERY_OR ) bOr = 1;
+      if( p->eType==FTSQUERY_NEAR ) pNear = p;
+      if( p->bEof ) bTreeEof = 1;
+    }
+    if( bOr==0 ) return SQLITE_OK;
+    pRun = pNear;
+    while( pRun->bDeferred ){
+      assert( pRun->pParent );
+      pRun = pRun->pParent;
+    }
+
+    /* This is the descendent of an OR node. In this case we cannot use
+    ** an incremental phrase. Load the entire doclist for the phrase
+    ** into memory in this case.  */
+    if( pPhrase->bIncr ){
+      int bEofSave = pRun->bEof;
+      fts3EvalRestart(pCsr, pRun, &rc);
+      while( rc==SQLITE_OK && !pRun->bEof ){
+        fts3EvalNextRow(pCsr, pRun, &rc);
+        if( bEofSave==0 && pRun->iDocid==iDocid ) break;
+      }
+      assert( rc!=SQLITE_OK || pPhrase->bIncr==0 );
+      if( rc==SQLITE_OK && pRun->bEof!=bEofSave ){
+        rc = FTS_CORRUPT_VTAB;
+      }
+    }
+    if( bTreeEof ){
+      while( rc==SQLITE_OK && !pRun->bEof ){
+        fts3EvalNextRow(pCsr, pRun, &rc);
+      }
+    }
+    if( rc!=SQLITE_OK ) return rc;
+
+    bMatch = 1;
+    for(p=pNear; p; p=p->pLeft){
+      u8 bEof = 0;
+      Fts3Expr *pTest = p;
+      Fts3Phrase *pPh;
+      assert( pTest->eType==FTSQUERY_NEAR || pTest->eType==FTSQUERY_PHRASE );
+      if( pTest->eType==FTSQUERY_NEAR ) pTest = pTest->pRight;
+      assert( pTest->eType==FTSQUERY_PHRASE );
+      pPh = pTest->pPhrase;
+
+      pIter = pPh->pOrPoslist;
+      iDocid = pPh->iOrDocid;
+      if( pCsr->bDesc==bDescDoclist ){
+        bEof = !pPh->doclist.nAll ||
+          (pIter >= (pPh->doclist.aAll + pPh->doclist.nAll));
+        while( (pIter==0 || DOCID_CMP(iDocid, pCsr->iPrevId)<0 ) && bEof==0 ){
+          sqlite3Fts3DoclistNext(
+              bDescDoclist, pPh->doclist.aAll, pPh->doclist.nAll,
+              &pIter, &iDocid, &bEof
+          );
+        }
+      }else{
+        bEof = !pPh->doclist.nAll || (pIter && pIter<=pPh->doclist.aAll);
+        while( (pIter==0 || DOCID_CMP(iDocid, pCsr->iPrevId)>0 ) && bEof==0 ){
+          int dummy;
+          sqlite3Fts3DoclistPrev(
+              bDescDoclist, pPh->doclist.aAll, pPh->doclist.nAll,
+              &pIter, &iDocid, &dummy, &bEof
+              );
+        }
+      }
+      pPh->pOrPoslist = pIter;
+      pPh->iOrDocid = iDocid;
+      if( bEof || iDocid!=pCsr->iPrevId ) bMatch = 0;
+    }
+
+    if( bMatch ){
+      pIter = pPhrase->pOrPoslist;
+    }else{
+      pIter = 0;
+    }
+  }
+  if( pIter==0 ) return SQLITE_OK;
+
+  if( *pIter==0x01 ){
+    pIter++;
+    pIter += fts3GetVarint32(pIter, &iThis);
+  }else{
+    iThis = 0;
+  }
+  while( iThis<iCol ){
+    fts3ColumnlistCopy(0, &pIter);
+    if( *pIter==0x00 ) return SQLITE_OK;
+    pIter++;
+    pIter += fts3GetVarint32(pIter, &iThis);
+  }
+  if( *pIter==0x00 ){
+    pIter = 0;
+  }
+
+  *ppOut = ((iCol==iThis)?pIter:0);
+  return SQLITE_OK;
+}
+
+/*
+** Free all components of the Fts3Phrase structure that were allocated by
+** the eval module. Specifically, this means to free:
+**
+**   * the contents of pPhrase->doclist, and
+**   * any Fts3MultiSegReader objects held by phrase tokens.
+*/
+SQLITE_PRIVATE void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *pPhrase){
+  if( pPhrase ){
+    int i;
+    sqlite3_free(pPhrase->doclist.aAll);
+    fts3EvalInvalidatePoslist(pPhrase);
+    memset(&pPhrase->doclist, 0, sizeof(Fts3Doclist));
+    for(i=0; i<pPhrase->nToken; i++){
+      fts3SegReaderCursorFree(pPhrase->aToken[i].pSegcsr);
+      pPhrase->aToken[i].pSegcsr = 0;
+    }
+  }
+}
+
+
+/*
+** Return SQLITE_CORRUPT_VTAB.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_PRIVATE int sqlite3Fts3Corrupt(){
+  return SQLITE_CORRUPT_VTAB;
+}
+#endif
+
+#if !defined(SQLITE_CORE)
+/*
+** Initialize API pointer table, if required.
+*/
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_fts3_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi)
+  return sqlite3Fts3Init(db);
+}
+#endif
+
+#endif
+
+/************** End of fts3.c ************************************************/
+/************** Begin file fts3_aux.c ****************************************/
+/*
+** 2011 Jan 27
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+typedef struct Fts3auxTable Fts3auxTable;
+typedef struct Fts3auxCursor Fts3auxCursor;
+
+struct Fts3auxTable {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  Fts3Table *pFts3Tab;
+};
+
+struct Fts3auxCursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  Fts3MultiSegReader csr;        /* Must be right after "base" */
+  Fts3SegFilter filter;
+  char *zStop;
+  int nStop;                      /* Byte-length of string zStop */
+  int iLangid;                    /* Language id to query */
+  int isEof;                      /* True if cursor is at EOF */
+  sqlite3_int64 iRowid;           /* Current rowid */
+
+  int iCol;                       /* Current value of 'col' column */
+  int nStat;                      /* Size of aStat[] array */
+  struct Fts3auxColstats {
+    sqlite3_int64 nDoc;           /* 'documents' values for current csr row */
+    sqlite3_int64 nOcc;           /* 'occurrences' values for current csr row */
+  } *aStat;
+};
+
+/*
+** Schema of the terms table.
+*/
+#define FTS3_AUX_SCHEMA \
+  "CREATE TABLE x(term, col, documents, occurrences, languageid HIDDEN)"
+
+/*
+** This function does all the work for both the xConnect and xCreate methods.
+** These tables have no persistent representation of their own, so xConnect
+** and xCreate are identical operations.
+*/
+static int fts3auxConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pUnused,                  /* Unused */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  char const *zDb;                /* Name of database (e.g. "main") */
+  char const *zFts3;              /* Name of fts3 table */
+  int nDb;                        /* Result of strlen(zDb) */
+  int nFts3;                      /* Result of strlen(zFts3) */
+  sqlite3_int64 nByte;            /* Bytes of space to allocate here */
+  int rc;                         /* value returned by declare_vtab() */
+  Fts3auxTable *p;                /* Virtual table object to return */
+
+  UNUSED_PARAMETER(pUnused);
+
+  /* The user should invoke this in one of two forms:
+  **
+  **     CREATE VIRTUAL TABLE xxx USING fts4aux(fts4-table);
+  **     CREATE VIRTUAL TABLE xxx USING fts4aux(fts4-table-db, fts4-table);
+  */
+  if( argc!=4 && argc!=5 ) goto bad_args;
+
+  zDb = argv[1];
+  nDb = (int)strlen(zDb);
+  if( argc==5 ){
+    if( nDb==4 && 0==sqlite3_strnicmp("temp", zDb, 4) ){
+      zDb = argv[3];
+      nDb = (int)strlen(zDb);
+      zFts3 = argv[4];
+    }else{
+      goto bad_args;
+    }
+  }else{
+    zFts3 = argv[3];
+  }
+  nFts3 = (int)strlen(zFts3);
+
+  rc = sqlite3_declare_vtab(db, FTS3_AUX_SCHEMA);
+  if( rc!=SQLITE_OK ) return rc;
+
+  nByte = sizeof(Fts3auxTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
+  p = (Fts3auxTable *)sqlite3_malloc64(nByte);
+  if( !p ) return SQLITE_NOMEM;
+  memset(p, 0, nByte);
+
+  p->pFts3Tab = (Fts3Table *)&p[1];
+  p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
+  p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
+  p->pFts3Tab->db = db;
+  p->pFts3Tab->nIndex = 1;
+
+  memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
+  memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
+  sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);
+
+  *ppVtab = (sqlite3_vtab *)p;
+  return SQLITE_OK;
+
+ bad_args:
+  sqlite3Fts3ErrMsg(pzErr, "invalid arguments to fts4aux constructor");
+  return SQLITE_ERROR;
+}
+
+/*
+** This function does the work for both the xDisconnect and xDestroy methods.
+** These tables have no persistent representation of their own, so xDisconnect
+** and xDestroy are identical operations.
+*/
+static int fts3auxDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3auxTable *p = (Fts3auxTable *)pVtab;
+  Fts3Table *pFts3 = p->pFts3Tab;
+  int i;
+
+  /* Free any prepared statements held */
+  for(i=0; i<SizeofArray(pFts3->aStmt); i++){
+    sqlite3_finalize(pFts3->aStmt[i]);
+  }
+  sqlite3_free(pFts3->zSegmentsTbl);
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+#define FTS4AUX_EQ_CONSTRAINT 1
+#define FTS4AUX_GE_CONSTRAINT 2
+#define FTS4AUX_LE_CONSTRAINT 4
+
+/*
+** xBestIndex - Analyze a WHERE and ORDER BY clause.
+*/
+static int fts3auxBestIndexMethod(
+  sqlite3_vtab *pVTab,
+  sqlite3_index_info *pInfo
+){
+  int i;
+  int iEq = -1;
+  int iGe = -1;
+  int iLe = -1;
+  int iLangid = -1;
+  int iNext = 1;                  /* Next free argvIndex value */
+
+  UNUSED_PARAMETER(pVTab);
+
+  /* This vtab delivers always results in "ORDER BY term ASC" order. */
+  if( pInfo->nOrderBy==1
+   && pInfo->aOrderBy[0].iColumn==0
+   && pInfo->aOrderBy[0].desc==0
+  ){
+    pInfo->orderByConsumed = 1;
+  }
+
+  /* Search for equality and range constraints on the "term" column.
+  ** And equality constraints on the hidden "languageid" column. */
+  for(i=0; i<pInfo->nConstraint; i++){
+    if( pInfo->aConstraint[i].usable ){
+      int op = pInfo->aConstraint[i].op;
+      int iCol = pInfo->aConstraint[i].iColumn;
+
+      if( iCol==0 ){
+        if( op==SQLITE_INDEX_CONSTRAINT_EQ ) iEq = i;
+        if( op==SQLITE_INDEX_CONSTRAINT_LT ) iLe = i;
+        if( op==SQLITE_INDEX_CONSTRAINT_LE ) iLe = i;
+        if( op==SQLITE_INDEX_CONSTRAINT_GT ) iGe = i;
+        if( op==SQLITE_INDEX_CONSTRAINT_GE ) iGe = i;
+      }
+      if( iCol==4 ){
+        if( op==SQLITE_INDEX_CONSTRAINT_EQ ) iLangid = i;
+      }
+    }
+  }
+
+  if( iEq>=0 ){
+    pInfo->idxNum = FTS4AUX_EQ_CONSTRAINT;
+    pInfo->aConstraintUsage[iEq].argvIndex = iNext++;
+    pInfo->estimatedCost = 5;
+  }else{
+    pInfo->idxNum = 0;
+    pInfo->estimatedCost = 20000;
+    if( iGe>=0 ){
+      pInfo->idxNum += FTS4AUX_GE_CONSTRAINT;
+      pInfo->aConstraintUsage[iGe].argvIndex = iNext++;
+      pInfo->estimatedCost /= 2;
+    }
+    if( iLe>=0 ){
+      pInfo->idxNum += FTS4AUX_LE_CONSTRAINT;
+      pInfo->aConstraintUsage[iLe].argvIndex = iNext++;
+      pInfo->estimatedCost /= 2;
+    }
+  }
+  if( iLangid>=0 ){
+    pInfo->aConstraintUsage[iLangid].argvIndex = iNext++;
+    pInfo->estimatedCost--;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** xOpen - Open a cursor.
+*/
+static int fts3auxOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  Fts3auxCursor *pCsr;            /* Pointer to cursor object to return */
+
+  UNUSED_PARAMETER(pVTab);
+
+  pCsr = (Fts3auxCursor *)sqlite3_malloc(sizeof(Fts3auxCursor));
+  if( !pCsr ) return SQLITE_NOMEM;
+  memset(pCsr, 0, sizeof(Fts3auxCursor));
+
+  *ppCsr = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** xClose - Close a cursor.
+*/
+static int fts3auxCloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+
+  sqlite3Fts3SegmentsClose(pFts3);
+  sqlite3Fts3SegReaderFinish(&pCsr->csr);
+  sqlite3_free((void *)pCsr->filter.zTerm);
+  sqlite3_free(pCsr->zStop);
+  sqlite3_free(pCsr->aStat);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+static int fts3auxGrowStatArray(Fts3auxCursor *pCsr, int nSize){
+  if( nSize>pCsr->nStat ){
+    struct Fts3auxColstats *aNew;
+    aNew = (struct Fts3auxColstats *)sqlite3_realloc64(pCsr->aStat,
+        sizeof(struct Fts3auxColstats) * nSize
+    );
+    if( aNew==0 ) return SQLITE_NOMEM;
+    memset(&aNew[pCsr->nStat], 0,
+        sizeof(struct Fts3auxColstats) * (nSize - pCsr->nStat)
+    );
+    pCsr->aStat = aNew;
+    pCsr->nStat = nSize;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** xNext - Advance the cursor to the next row, if any.
+*/
+static int fts3auxNextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+  int rc;
+
+  /* Increment our pretend rowid value. */
+  pCsr->iRowid++;
+
+  for(pCsr->iCol++; pCsr->iCol<pCsr->nStat; pCsr->iCol++){
+    if( pCsr->aStat[pCsr->iCol].nDoc>0 ) return SQLITE_OK;
+  }
+
+  rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
+  if( rc==SQLITE_ROW ){
+    int i = 0;
+    int nDoclist = pCsr->csr.nDoclist;
+    char *aDoclist = pCsr->csr.aDoclist;
+    int iCol;
+
+    int eState = 0;
+
+    if( pCsr->zStop ){
+      int n = (pCsr->nStop<pCsr->csr.nTerm) ? pCsr->nStop : pCsr->csr.nTerm;
+      int mc = memcmp(pCsr->zStop, pCsr->csr.zTerm, n);
+      if( mc<0 || (mc==0 && pCsr->csr.nTerm>pCsr->nStop) ){
+        pCsr->isEof = 1;
+        return SQLITE_OK;
+      }
+    }
+
+    if( fts3auxGrowStatArray(pCsr, 2) ) return SQLITE_NOMEM;
+    memset(pCsr->aStat, 0, sizeof(struct Fts3auxColstats) * pCsr->nStat);
+    iCol = 0;
+    rc = SQLITE_OK;
+
+    while( i<nDoclist ){
+      sqlite3_int64 v = 0;
+
+      i += sqlite3Fts3GetVarint(&aDoclist[i], &v);
+      switch( eState ){
+        /* State 0. In this state the integer just read was a docid. */
+        case 0:
+          pCsr->aStat[0].nDoc++;
+          eState = 1;
+          iCol = 0;
+          break;
+
+        /* State 1. In this state we are expecting either a 1, indicating
+        ** that the following integer will be a column number, or the
+        ** start of a position list for column 0.
+        **
+        ** The only difference between state 1 and state 2 is that if the
+        ** integer encountered in state 1 is not 0 or 1, then we need to
+        ** increment the column 0 "nDoc" count for this term.
+        */
+        case 1:
+          assert( iCol==0 );
+          if( v>1 ){
+            pCsr->aStat[1].nDoc++;
+          }
+          eState = 2;
+          /* fall through */
+
+        case 2:
+          if( v==0 ){       /* 0x00. Next integer will be a docid. */
+            eState = 0;
+          }else if( v==1 ){ /* 0x01. Next integer will be a column number. */
+            eState = 3;
+          }else{            /* 2 or greater. A position. */
+            pCsr->aStat[iCol+1].nOcc++;
+            pCsr->aStat[0].nOcc++;
+          }
+          break;
+
+        /* State 3. The integer just read is a column number. */
+        default: assert( eState==3 );
+          iCol = (int)v;
+          if( iCol<1 ){
+            rc = SQLITE_CORRUPT_VTAB;
+            break;
+          }
+          if( fts3auxGrowStatArray(pCsr, iCol+2) ) return SQLITE_NOMEM;
+          pCsr->aStat[iCol+1].nDoc++;
+          eState = 2;
+          break;
+      }
+    }
+
+    pCsr->iCol = 0;
+  }else{
+    pCsr->isEof = 1;
+  }
+  return rc;
+}
+
+/*
+** xFilter - Initialize a cursor to point at the start of its data.
+*/
+static int fts3auxFilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+  int rc;
+  int isScan = 0;
+  int iLangVal = 0;               /* Language id to query */
+
+  int iEq = -1;                   /* Index of term=? value in apVal */
+  int iGe = -1;                   /* Index of term>=? value in apVal */
+  int iLe = -1;                   /* Index of term<=? value in apVal */
+  int iLangid = -1;               /* Index of languageid=? value in apVal */
+  int iNext = 0;
+
+  UNUSED_PARAMETER(nVal);
+  UNUSED_PARAMETER(idxStr);
+
+  assert( idxStr==0 );
+  assert( idxNum==FTS4AUX_EQ_CONSTRAINT || idxNum==0
+       || idxNum==FTS4AUX_LE_CONSTRAINT || idxNum==FTS4AUX_GE_CONSTRAINT
+       || idxNum==(FTS4AUX_LE_CONSTRAINT|FTS4AUX_GE_CONSTRAINT)
+  );
+
+  if( idxNum==FTS4AUX_EQ_CONSTRAINT ){
+    iEq = iNext++;
+  }else{
+    isScan = 1;
+    if( idxNum & FTS4AUX_GE_CONSTRAINT ){
+      iGe = iNext++;
+    }
+    if( idxNum & FTS4AUX_LE_CONSTRAINT ){
+      iLe = iNext++;
+    }
+  }
+  if( iNext<nVal ){
+    iLangid = iNext++;
+  }
+
+  /* In case this cursor is being reused, close and zero it. */
+  testcase(pCsr->filter.zTerm);
+  sqlite3Fts3SegReaderFinish(&pCsr->csr);
+  sqlite3_free((void *)pCsr->filter.zTerm);
+  sqlite3_free(pCsr->aStat);
+  sqlite3_free(pCsr->zStop);
+  memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);
+
+  pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
+  if( isScan ) pCsr->filter.flags |= FTS3_SEGMENT_SCAN;
+
+  if( iEq>=0 || iGe>=0 ){
+    const unsigned char *zStr = sqlite3_value_text(apVal[0]);
+    assert( (iEq==0 && iGe==-1) || (iEq==-1 && iGe==0) );
+    if( zStr ){
+      pCsr->filter.zTerm = sqlite3_mprintf("%s", zStr);
+      if( pCsr->filter.zTerm==0 ) return SQLITE_NOMEM;
+      pCsr->filter.nTerm = (int)strlen(pCsr->filter.zTerm);
+    }
+  }
+
+  if( iLe>=0 ){
+    pCsr->zStop = sqlite3_mprintf("%s", sqlite3_value_text(apVal[iLe]));
+    if( pCsr->zStop==0 ) return SQLITE_NOMEM;
+    pCsr->nStop = (int)strlen(pCsr->zStop);
+  }
+
+  if( iLangid>=0 ){
+    iLangVal = sqlite3_value_int(apVal[iLangid]);
+
+    /* If the user specified a negative value for the languageid, use zero
+    ** instead. This works, as the "languageid=?" constraint will also
+    ** be tested by the VDBE layer. The test will always be false (since
+    ** this module will not return a row with a negative languageid), and
+    ** so the overall query will return zero rows.  */
+    if( iLangVal<0 ) iLangVal = 0;
+  }
+  pCsr->iLangid = iLangVal;
+
+  rc = sqlite3Fts3SegReaderCursor(pFts3, iLangVal, 0, FTS3_SEGCURSOR_ALL,
+      pCsr->filter.zTerm, pCsr->filter.nTerm, 0, isScan, &pCsr->csr
+  );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
+  }
+
+  if( rc==SQLITE_OK ) rc = fts3auxNextMethod(pCursor);
+  return rc;
+}
+
+/*
+** xEof - Return true if the cursor is at EOF, or false otherwise.
+*/
+static int fts3auxEofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  return pCsr->isEof;
+}
+
+/*
+** xColumn - Return a column value.
+*/
+static int fts3auxColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts3auxCursor *p = (Fts3auxCursor *)pCursor;
+
+  assert( p->isEof==0 );
+  switch( iCol ){
+    case 0: /* term */
+      sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
+      break;
+
+    case 1: /* col */
+      if( p->iCol ){
+        sqlite3_result_int(pCtx, p->iCol-1);
+      }else{
+        sqlite3_result_text(pCtx, "*", -1, SQLITE_STATIC);
+      }
+      break;
+
+    case 2: /* documents */
+      sqlite3_result_int64(pCtx, p->aStat[p->iCol].nDoc);
+      break;
+
+    case 3: /* occurrences */
+      sqlite3_result_int64(pCtx, p->aStat[p->iCol].nOcc);
+      break;
+
+    default: /* languageid */
+      assert( iCol==4 );
+      sqlite3_result_int(pCtx, p->iLangid);
+      break;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** xRowid - Return the current rowid for the cursor.
+*/
+static int fts3auxRowidMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite_int64 *pRowid            /* OUT: Rowid value */
+){
+  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+  *pRowid = pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Register the fts3aux module with database connection db. Return SQLITE_OK
+** if successful or an error code if sqlite3_create_module() fails.
+*/
+SQLITE_PRIVATE int sqlite3Fts3InitAux(sqlite3 *db){
+  static const sqlite3_module fts3aux_module = {
+     0,                           /* iVersion      */
+     fts3auxConnectMethod,        /* xCreate       */
+     fts3auxConnectMethod,        /* xConnect      */
+     fts3auxBestIndexMethod,      /* xBestIndex    */
+     fts3auxDisconnectMethod,     /* xDisconnect   */
+     fts3auxDisconnectMethod,     /* xDestroy      */
+     fts3auxOpenMethod,           /* xOpen         */
+     fts3auxCloseMethod,          /* xClose        */
+     fts3auxFilterMethod,         /* xFilter       */
+     fts3auxNextMethod,           /* xNext         */
+     fts3auxEofMethod,            /* xEof          */
+     fts3auxColumnMethod,         /* xColumn       */
+     fts3auxRowidMethod,          /* xRowid        */
+     0,                           /* xUpdate       */
+     0,                           /* xBegin        */
+     0,                           /* xSync         */
+     0,                           /* xCommit       */
+     0,                           /* xRollback     */
+     0,                           /* xFindFunction */
+     0,                           /* xRename       */
+     0,                           /* xSavepoint    */
+     0,                           /* xRelease      */
+     0,                           /* xRollbackTo   */
+     0,                           /* xShadowName   */
+     0                            /* xIntegrity    */
+  };
+  int rc;                         /* Return code */
+
+  rc = sqlite3_create_module(db, "fts4aux", &fts3aux_module, 0);
+  return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_aux.c ********************************************/
+/************** Begin file fts3_expr.c ***************************************/
+/*
+** 2008 Nov 28
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This module contains code that implements a parser for fts3 query strings
+** (the right-hand argument to the MATCH operator). Because the supported
+** syntax is relatively simple, the whole tokenizer/parser system is
+** hand-coded.
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/*
+** By default, this module parses the legacy syntax that has been
+** traditionally used by fts3. Or, if SQLITE_ENABLE_FTS3_PARENTHESIS
+** is defined, then it uses the new syntax. The differences between
+** the new and the old syntaxes are:
+**
+**  a) The new syntax supports parenthesis. The old does not.
+**
+**  b) The new syntax supports the AND and NOT operators. The old does not.
+**
+**  c) The old syntax supports the "-" token qualifier. This is not
+**     supported by the new syntax (it is replaced by the NOT operator).
+**
+**  d) When using the old syntax, the OR operator has a greater precedence
+**     than an implicit AND. When using the new, both implicity and explicit
+**     AND operators have a higher precedence than OR.
+**
+** If compiled with SQLITE_TEST defined, then this module exports the
+** symbol "int sqlite3_fts3_enable_parentheses". Setting this variable
+** to zero causes the module to use the old syntax. If it is set to
+** non-zero the new syntax is activated. This is so both syntaxes can
+** be tested using a single build of testfixture.
+**
+** The following describes the syntax supported by the fts3 MATCH
+** operator in a similar format to that used by the lemon parser
+** generator. This module does not use actually lemon, it uses a
+** custom parser.
+**
+**   query ::= andexpr (OR andexpr)*.
+**
+**   andexpr ::= notexpr (AND? notexpr)*.
+**
+**   notexpr ::= nearexpr (NOT nearexpr|-TOKEN)*.
+**   notexpr ::= LP query RP.
+**
+**   nearexpr ::= phrase (NEAR distance_opt nearexpr)*.
+**
+**   distance_opt ::= .
+**   distance_opt ::= / INTEGER.
+**
+**   phrase ::= TOKEN.
+**   phrase ::= COLUMN:TOKEN.
+**   phrase ::= "TOKEN TOKEN TOKEN...".
+*/
+
+#ifdef SQLITE_TEST
+SQLITE_API int sqlite3_fts3_enable_parentheses = 0;
+#else
+# ifdef SQLITE_ENABLE_FTS3_PARENTHESIS
+#  define sqlite3_fts3_enable_parentheses 1
+# else
+#  define sqlite3_fts3_enable_parentheses 0
+# endif
+#endif
+
+/*
+** Default span for NEAR operators.
+*/
+#define SQLITE_FTS3_DEFAULT_NEAR_PARAM 10
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+/*
+** isNot:
+**   This variable is used by function getNextNode(). When getNextNode() is
+**   called, it sets ParseContext.isNot to true if the 'next node' is a
+**   FTSQUERY_PHRASE with a unary "-" attached to it. i.e. "mysql" in the
+**   FTS3 query "sqlite -mysql". Otherwise, ParseContext.isNot is set to
+**   zero.
+*/
+typedef struct ParseContext ParseContext;
+struct ParseContext {
+  sqlite3_tokenizer *pTokenizer;      /* Tokenizer module */
+  int iLangid;                        /* Language id used with tokenizer */
+  const char **azCol;                 /* Array of column names for fts3 table */
+  int bFts4;                          /* True to allow FTS4-only syntax */
+  int nCol;                           /* Number of entries in azCol[] */
+  int iDefaultCol;                    /* Default column to query */
+  int isNot;                          /* True if getNextNode() sees a unary - */
+  sqlite3_context *pCtx;              /* Write error message here */
+  int nNest;                          /* Number of nested brackets */
+};
+
+/*
+** This function is equivalent to the standard isspace() function.
+**
+** The standard isspace() can be awkward to use safely, because although it
+** is defined to accept an argument of type int, its behavior when passed
+** an integer that falls outside of the range of the unsigned char type
+** is undefined (and sometimes, "undefined" means segfault). This wrapper
+** is defined to accept an argument of type char, and always returns 0 for
+** any values that fall outside of the range of the unsigned char type (i.e.
+** negative values).
+*/
+static int fts3isspace(char c){
+  return c==' ' || c=='\t' || c=='\n' || c=='\r' || c=='\v' || c=='\f';
+}
+
+/*
+** Allocate nByte bytes of memory using sqlite3_malloc(). If successful,
+** zero the memory before returning a pointer to it. If unsuccessful,
+** return NULL.
+*/
+SQLITE_PRIVATE void *sqlite3Fts3MallocZero(sqlite3_int64 nByte){
+  void *pRet = sqlite3_malloc64(nByte);
+  if( pRet ) memset(pRet, 0, nByte);
+  return pRet;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3OpenTokenizer(
+  sqlite3_tokenizer *pTokenizer,
+  int iLangid,
+  const char *z,
+  int n,
+  sqlite3_tokenizer_cursor **ppCsr
+){
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  sqlite3_tokenizer_cursor *pCsr = 0;
+  int rc;
+
+  rc = pModule->xOpen(pTokenizer, z, n, &pCsr);
+  assert( rc==SQLITE_OK || pCsr==0 );
+  if( rc==SQLITE_OK ){
+    pCsr->pTokenizer = pTokenizer;
+    if( pModule->iVersion>=1 ){
+      rc = pModule->xLanguageid(pCsr, iLangid);
+      if( rc!=SQLITE_OK ){
+        pModule->xClose(pCsr);
+        pCsr = 0;
+      }
+    }
+  }
+  *ppCsr = pCsr;
+  return rc;
+}
+
+/*
+** Function getNextNode(), which is called by fts3ExprParse(), may itself
+** call fts3ExprParse(). So this forward declaration is required.
+*/
+static int fts3ExprParse(ParseContext *, const char *, int, Fts3Expr **, int *);
+
+/*
+** Extract the next token from buffer z (length n) using the tokenizer
+** and other information (column names etc.) in pParse. Create an Fts3Expr
+** structure of type FTSQUERY_PHRASE containing a phrase consisting of this
+** single token and set *ppExpr to point to it. If the end of the buffer is
+** reached before a token is found, set *ppExpr to zero. It is the
+** responsibility of the caller to eventually deallocate the allocated
+** Fts3Expr structure (if any) by passing it to sqlite3_free().
+**
+** Return SQLITE_OK if successful, or SQLITE_NOMEM if a memory allocation
+** fails.
+*/
+static int getNextToken(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  int iCol,                               /* Value for Fts3Phrase.iColumn */
+  const char *z, int n,                   /* Input string */
+  Fts3Expr **ppExpr,                      /* OUT: expression */
+  int *pnConsumed                         /* OUT: Number of bytes consumed */
+){
+  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  int rc;
+  sqlite3_tokenizer_cursor *pCursor;
+  Fts3Expr *pRet = 0;
+  int i = 0;
+
+  /* Set variable i to the maximum number of bytes of input to tokenize. */
+  for(i=0; i<n; i++){
+    if( sqlite3_fts3_enable_parentheses && (z[i]=='(' || z[i]==')') ) break;
+    if( z[i]=='"' ) break;
+  }
+
+  *pnConsumed = i;
+  rc = sqlite3Fts3OpenTokenizer(pTokenizer, pParse->iLangid, z, i, &pCursor);
+  if( rc==SQLITE_OK ){
+    const char *zToken;
+    int nToken = 0, iStart = 0, iEnd = 0, iPosition = 0;
+    sqlite3_int64 nByte;                    /* total space to allocate */
+
+    rc = pModule->xNext(pCursor, &zToken, &nToken, &iStart, &iEnd, &iPosition);
+    if( rc==SQLITE_OK ){
+      nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase) + nToken;
+      pRet = (Fts3Expr *)sqlite3Fts3MallocZero(nByte);
+      if( !pRet ){
+        rc = SQLITE_NOMEM;
+      }else{
+        pRet->eType = FTSQUERY_PHRASE;
+        pRet->pPhrase = (Fts3Phrase *)&pRet[1];
+        pRet->pPhrase->nToken = 1;
+        pRet->pPhrase->iColumn = iCol;
+        pRet->pPhrase->aToken[0].n = nToken;
+        pRet->pPhrase->aToken[0].z = (char *)&pRet->pPhrase[1];
+        memcpy(pRet->pPhrase->aToken[0].z, zToken, nToken);
+
+        if( iEnd<n && z[iEnd]=='*' ){
+          pRet->pPhrase->aToken[0].isPrefix = 1;
+          iEnd++;
+        }
+
+        while( 1 ){
+          if( !sqlite3_fts3_enable_parentheses
+           && iStart>0 && z[iStart-1]=='-'
+          ){
+            pParse->isNot = 1;
+            iStart--;
+          }else if( pParse->bFts4 && iStart>0 && z[iStart-1]=='^' ){
+            pRet->pPhrase->aToken[0].bFirst = 1;
+            iStart--;
+          }else{
+            break;
+          }
+        }
+
+      }
+      *pnConsumed = iEnd;
+    }else if( i && rc==SQLITE_DONE ){
+      rc = SQLITE_OK;
+    }
+
+    pModule->xClose(pCursor);
+  }
+
+  *ppExpr = pRet;
+  return rc;
+}
+
+
+/*
+** Enlarge a memory allocation.  If an out-of-memory allocation occurs,
+** then free the old allocation.
+*/
+static void *fts3ReallocOrFree(void *pOrig, sqlite3_int64 nNew){
+  void *pRet = sqlite3_realloc64(pOrig, nNew);
+  if( !pRet ){
+    sqlite3_free(pOrig);
+  }
+  return pRet;
+}
+
+/*
+** Buffer zInput, length nInput, contains the contents of a quoted string
+** that appeared as part of an fts3 query expression. Neither quote character
+** is included in the buffer. This function attempts to tokenize the entire
+** input buffer and create an Fts3Expr structure of type FTSQUERY_PHRASE
+** containing the results.
+**
+** If successful, SQLITE_OK is returned and *ppExpr set to point at the
+** allocated Fts3Expr structure. Otherwise, either SQLITE_NOMEM (out of memory
+** error) or SQLITE_ERROR (tokenization error) is returned and *ppExpr set
+** to 0.
+*/
+static int getNextString(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  const char *zInput, int nInput,         /* Input string */
+  Fts3Expr **ppExpr                       /* OUT: expression */
+){
+  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  int rc;
+  Fts3Expr *p = 0;
+  sqlite3_tokenizer_cursor *pCursor = 0;
+  char *zTemp = 0;
+  int nTemp = 0;
+
+  const int nSpace = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
+  int nToken = 0;
+
+  /* The final Fts3Expr data structure, including the Fts3Phrase,
+  ** Fts3PhraseToken structures token buffers are all stored as a single
+  ** allocation so that the expression can be freed with a single call to
+  ** sqlite3_free(). Setting this up requires a two pass approach.
+  **
+  ** The first pass, in the block below, uses a tokenizer cursor to iterate
+  ** through the tokens in the expression. This pass uses fts3ReallocOrFree()
+  ** to assemble data in two dynamic buffers:
+  **
+  **   Buffer p: Points to the Fts3Expr structure, followed by the Fts3Phrase
+  **             structure, followed by the array of Fts3PhraseToken
+  **             structures. This pass only populates the Fts3PhraseToken array.
+  **
+  **   Buffer zTemp: Contains copies of all tokens.
+  **
+  ** The second pass, in the block that begins "if( rc==SQLITE_DONE )" below,
+  ** appends buffer zTemp to buffer p, and fills in the Fts3Expr and Fts3Phrase
+  ** structures.
+  */
+  rc = sqlite3Fts3OpenTokenizer(
+      pTokenizer, pParse->iLangid, zInput, nInput, &pCursor);
+  if( rc==SQLITE_OK ){
+    int ii;
+    for(ii=0; rc==SQLITE_OK; ii++){
+      const char *zByte;
+      int nByte = 0, iBegin = 0, iEnd = 0, iPos = 0;
+      rc = pModule->xNext(pCursor, &zByte, &nByte, &iBegin, &iEnd, &iPos);
+      if( rc==SQLITE_OK ){
+        Fts3PhraseToken *pToken;
+
+        p = fts3ReallocOrFree(p, nSpace + ii*sizeof(Fts3PhraseToken));
+        zTemp = fts3ReallocOrFree(zTemp, nTemp + nByte);
+        if( !zTemp || !p ){
+          rc = SQLITE_NOMEM;
+          goto getnextstring_out;
+        }
+
+        assert( nToken==ii );
+        pToken = &((Fts3Phrase *)(&p[1]))->aToken[ii];
+        memset(pToken, 0, sizeof(Fts3PhraseToken));
+
+        memcpy(&zTemp[nTemp], zByte, nByte);
+        nTemp += nByte;
+
+        pToken->n = nByte;
+        pToken->isPrefix = (iEnd<nInput && zInput[iEnd]=='*');
+        pToken->bFirst = (iBegin>0 && zInput[iBegin-1]=='^');
+        nToken = ii+1;
+      }
+    }
+  }
+
+  if( rc==SQLITE_DONE ){
+    int jj;
+    char *zBuf = 0;
+
+    p = fts3ReallocOrFree(p, nSpace + nToken*sizeof(Fts3PhraseToken) + nTemp);
+    if( !p ){
+      rc = SQLITE_NOMEM;
+      goto getnextstring_out;
+    }
+    memset(p, 0, (char *)&(((Fts3Phrase *)&p[1])->aToken[0])-(char *)p);
+    p->eType = FTSQUERY_PHRASE;
+    p->pPhrase = (Fts3Phrase *)&p[1];
+    p->pPhrase->iColumn = pParse->iDefaultCol;
+    p->pPhrase->nToken = nToken;
+
+    zBuf = (char *)&p->pPhrase->aToken[nToken];
+    assert( nTemp==0 || zTemp );
+    if( zTemp ){
+      memcpy(zBuf, zTemp, nTemp);
+    }
+
+    for(jj=0; jj<p->pPhrase->nToken; jj++){
+      p->pPhrase->aToken[jj].z = zBuf;
+      zBuf += p->pPhrase->aToken[jj].n;
+    }
+    rc = SQLITE_OK;
+  }
+
+ getnextstring_out:
+  if( pCursor ){
+    pModule->xClose(pCursor);
+  }
+  sqlite3_free(zTemp);
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(p);
+    p = 0;
+  }
+  *ppExpr = p;
+  return rc;
+}
+
+/*
+** The output variable *ppExpr is populated with an allocated Fts3Expr
+** structure, or set to 0 if the end of the input buffer is reached.
+**
+** Returns an SQLite error code. SQLITE_OK if everything works, SQLITE_NOMEM
+** if a malloc failure occurs, or SQLITE_ERROR if a parse error is encountered.
+** If SQLITE_ERROR is returned, pContext is populated with an error message.
+*/
+static int getNextNode(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  const char *z, int n,                   /* Input string */
+  Fts3Expr **ppExpr,                      /* OUT: expression */
+  int *pnConsumed                         /* OUT: Number of bytes consumed */
+){
+  static const struct Fts3Keyword {
+    char *z;                              /* Keyword text */
+    unsigned char n;                      /* Length of the keyword */
+    unsigned char parenOnly;              /* Only valid in paren mode */
+    unsigned char eType;                  /* Keyword code */
+  } aKeyword[] = {
+    { "OR" ,  2, 0, FTSQUERY_OR   },
+    { "AND",  3, 1, FTSQUERY_AND  },
+    { "NOT",  3, 1, FTSQUERY_NOT  },
+    { "NEAR", 4, 0, FTSQUERY_NEAR }
+  };
+  int ii;
+  int iCol;
+  int iColLen;
+  int rc;
+  Fts3Expr *pRet = 0;
+
+  const char *zInput = z;
+  int nInput = n;
+
+  pParse->isNot = 0;
+
+  /* Skip over any whitespace before checking for a keyword, an open or
+  ** close bracket, or a quoted string.
+  */
+  while( nInput>0 && fts3isspace(*zInput) ){
+    nInput--;
+    zInput++;
+  }
+  if( nInput==0 ){
+    return SQLITE_DONE;
+  }
+
+  /* See if we are dealing with a keyword. */
+  for(ii=0; ii<(int)(sizeof(aKeyword)/sizeof(struct Fts3Keyword)); ii++){
+    const struct Fts3Keyword *pKey = &aKeyword[ii];
+
+    if( (pKey->parenOnly & ~sqlite3_fts3_enable_parentheses)!=0 ){
+      continue;
+    }
+
+    if( nInput>=pKey->n && 0==memcmp(zInput, pKey->z, pKey->n) ){
+      int nNear = SQLITE_FTS3_DEFAULT_NEAR_PARAM;
+      int nKey = pKey->n;
+      char cNext;
+
+      /* If this is a "NEAR" keyword, check for an explicit nearness. */
+      if( pKey->eType==FTSQUERY_NEAR ){
+        assert( nKey==4 );
+        if( zInput[4]=='/' && zInput[5]>='0' && zInput[5]<='9' ){
+          nKey += 1+sqlite3Fts3ReadInt(&zInput[nKey+1], &nNear);
+        }
+      }
+
+      /* At this point this is probably a keyword. But for that to be true,
+      ** the next byte must contain either whitespace, an open or close
+      ** parenthesis, a quote character, or EOF.
+      */
+      cNext = zInput[nKey];
+      if( fts3isspace(cNext)
+       || cNext=='"' || cNext=='(' || cNext==')' || cNext==0
+      ){
+        pRet = (Fts3Expr *)sqlite3Fts3MallocZero(sizeof(Fts3Expr));
+        if( !pRet ){
+          return SQLITE_NOMEM;
+        }
+        pRet->eType = pKey->eType;
+        pRet->nNear = nNear;
+        *ppExpr = pRet;
+        *pnConsumed = (int)((zInput - z) + nKey);
+        return SQLITE_OK;
+      }
+
+      /* Turns out that wasn't a keyword after all. This happens if the
+      ** user has supplied a token such as "ORacle". Continue.
+      */
+    }
+  }
+
+  /* See if we are dealing with a quoted phrase. If this is the case, then
+  ** search for the closing quote and pass the whole string to getNextString()
+  ** for processing. This is easy to do, as fts3 has no syntax for escaping
+  ** a quote character embedded in a string.
+  */
+  if( *zInput=='"' ){
+    for(ii=1; ii<nInput && zInput[ii]!='"'; ii++);
+    *pnConsumed = (int)((zInput - z) + ii + 1);
+    if( ii==nInput ){
+      return SQLITE_ERROR;
+    }
+    return getNextString(pParse, &zInput[1], ii-1, ppExpr);
+  }
+
+  if( sqlite3_fts3_enable_parentheses ){
+    if( *zInput=='(' ){
+      int nConsumed = 0;
+      pParse->nNest++;
+#if !defined(SQLITE_MAX_EXPR_DEPTH)
+      if( pParse->nNest>1000 ) return SQLITE_ERROR;
+#elif SQLITE_MAX_EXPR_DEPTH>0
+      if( pParse->nNest>SQLITE_MAX_EXPR_DEPTH ) return SQLITE_ERROR;
+#endif
+      rc = fts3ExprParse(pParse, zInput+1, nInput-1, ppExpr, &nConsumed);
+      *pnConsumed = (int)(zInput - z) + 1 + nConsumed;
+      return rc;
+    }else if( *zInput==')' ){
+      pParse->nNest--;
+      *pnConsumed = (int)((zInput - z) + 1);
+      *ppExpr = 0;
+      return SQLITE_DONE;
+    }
+  }
+
+  /* If control flows to this point, this must be a regular token, or
+  ** the end of the input. Read a regular token using the sqlite3_tokenizer
+  ** interface. Before doing so, figure out if there is an explicit
+  ** column specifier for the token.
+  **
+  ** TODO: Strangely, it is not possible to associate a column specifier
+  ** with a quoted phrase, only with a single token. Not sure if this was
+  ** an implementation artifact or an intentional decision when fts3 was
+  ** first implemented. Whichever it was, this module duplicates the
+  ** limitation.
+  */
+  iCol = pParse->iDefaultCol;
+  iColLen = 0;
+  for(ii=0; ii<pParse->nCol; ii++){
+    const char *zStr = pParse->azCol[ii];
+    int nStr = (int)strlen(zStr);
+    if( nInput>nStr && zInput[nStr]==':'
+     && sqlite3_strnicmp(zStr, zInput, nStr)==0
+    ){
+      iCol = ii;
+      iColLen = (int)((zInput - z) + nStr + 1);
+      break;
+    }
+  }
+  rc = getNextToken(pParse, iCol, &z[iColLen], n-iColLen, ppExpr, pnConsumed);
+  *pnConsumed += iColLen;
+  return rc;
+}
+
+/*
+** The argument is an Fts3Expr structure for a binary operator (any type
+** except an FTSQUERY_PHRASE). Return an integer value representing the
+** precedence of the operator. Lower values have a higher precedence (i.e.
+** group more tightly). For example, in the C language, the == operator
+** groups more tightly than ||, and would therefore have a higher precedence.
+**
+** When using the new fts3 query syntax (when SQLITE_ENABLE_FTS3_PARENTHESIS
+** is defined), the order of the operators in precedence from highest to
+** lowest is:
+**
+**   NEAR
+**   NOT
+**   AND (including implicit ANDs)
+**   OR
+**
+** Note that when using the old query syntax, the OR operator has a higher
+** precedence than the AND operator.
+*/
+static int opPrecedence(Fts3Expr *p){
+  assert( p->eType!=FTSQUERY_PHRASE );
+  if( sqlite3_fts3_enable_parentheses ){
+    return p->eType;
+  }else if( p->eType==FTSQUERY_NEAR ){
+    return 1;
+  }else if( p->eType==FTSQUERY_OR ){
+    return 2;
+  }
+  assert( p->eType==FTSQUERY_AND );
+  return 3;
+}
+
+/*
+** Argument ppHead contains a pointer to the current head of a query
+** expression tree being parsed. pPrev is the expression node most recently
+** inserted into the tree. This function adds pNew, which is always a binary
+** operator node, into the expression tree based on the relative precedence
+** of pNew and the existing nodes of the tree. This may result in the head
+** of the tree changing, in which case *ppHead is set to the new root node.
+*/
+static void insertBinaryOperator(
+  Fts3Expr **ppHead,       /* Pointer to the root node of a tree */
+  Fts3Expr *pPrev,         /* Node most recently inserted into the tree */
+  Fts3Expr *pNew           /* New binary node to insert into expression tree */
+){
+  Fts3Expr *pSplit = pPrev;
+  while( pSplit->pParent && opPrecedence(pSplit->pParent)<=opPrecedence(pNew) ){
+    pSplit = pSplit->pParent;
+  }
+
+  if( pSplit->pParent ){
+    assert( pSplit->pParent->pRight==pSplit );
+    pSplit->pParent->pRight = pNew;
+    pNew->pParent = pSplit->pParent;
+  }else{
+    *ppHead = pNew;
+  }
+  pNew->pLeft = pSplit;
+  pSplit->pParent = pNew;
+}
+
+/*
+** Parse the fts3 query expression found in buffer z, length n. This function
+** returns either when the end of the buffer is reached or an unmatched
+** closing bracket - ')' - is encountered.
+**
+** If successful, SQLITE_OK is returned, *ppExpr is set to point to the
+** parsed form of the expression and *pnConsumed is set to the number of
+** bytes read from buffer z. Otherwise, *ppExpr is set to 0 and SQLITE_NOMEM
+** (out of memory error) or SQLITE_ERROR (parse error) is returned.
+*/
+static int fts3ExprParse(
+  ParseContext *pParse,                   /* fts3 query parse context */
+  const char *z, int n,                   /* Text of MATCH query */
+  Fts3Expr **ppExpr,                      /* OUT: Parsed query structure */
+  int *pnConsumed                         /* OUT: Number of bytes consumed */
+){
+  Fts3Expr *pRet = 0;
+  Fts3Expr *pPrev = 0;
+  Fts3Expr *pNotBranch = 0;               /* Only used in legacy parse mode */
+  int nIn = n;
+  const char *zIn = z;
+  int rc = SQLITE_OK;
+  int isRequirePhrase = 1;
+
+  while( rc==SQLITE_OK ){
+    Fts3Expr *p = 0;
+    int nByte = 0;
+
+    rc = getNextNode(pParse, zIn, nIn, &p, &nByte);
+    assert( nByte>0 || (rc!=SQLITE_OK && p==0) );
+    if( rc==SQLITE_OK ){
+      if( p ){
+        int isPhrase;
+
+        if( !sqlite3_fts3_enable_parentheses
+            && p->eType==FTSQUERY_PHRASE && pParse->isNot
+        ){
+          /* Create an implicit NOT operator. */
+          Fts3Expr *pNot = sqlite3Fts3MallocZero(sizeof(Fts3Expr));
+          if( !pNot ){
+            sqlite3Fts3ExprFree(p);
+            rc = SQLITE_NOMEM;
+            goto exprparse_out;
+          }
+          pNot->eType = FTSQUERY_NOT;
+          pNot->pRight = p;
+          p->pParent = pNot;
+          if( pNotBranch ){
+            pNot->pLeft = pNotBranch;
+            pNotBranch->pParent = pNot;
+          }
+          pNotBranch = pNot;
+          p = pPrev;
+        }else{
+          int eType = p->eType;
+          isPhrase = (eType==FTSQUERY_PHRASE || p->pLeft);
+
+          /* The isRequirePhrase variable is set to true if a phrase or
+          ** an expression contained in parenthesis is required. If a
+          ** binary operator (AND, OR, NOT or NEAR) is encounted when
+          ** isRequirePhrase is set, this is a syntax error.
+          */
+          if( !isPhrase && isRequirePhrase ){
+            sqlite3Fts3ExprFree(p);
+            rc = SQLITE_ERROR;
+            goto exprparse_out;
+          }
+
+          if( isPhrase && !isRequirePhrase ){
+            /* Insert an implicit AND operator. */
+            Fts3Expr *pAnd;
+            assert( pRet && pPrev );
+            pAnd = sqlite3Fts3MallocZero(sizeof(Fts3Expr));
+            if( !pAnd ){
+              sqlite3Fts3ExprFree(p);
+              rc = SQLITE_NOMEM;
+              goto exprparse_out;
+            }
+            pAnd->eType = FTSQUERY_AND;
+            insertBinaryOperator(&pRet, pPrev, pAnd);
+            pPrev = pAnd;
+          }
+
+          /* This test catches attempts to make either operand of a NEAR
+           ** operator something other than a phrase. For example, either of
+           ** the following:
+           **
+           **    (bracketed expression) NEAR phrase
+           **    phrase NEAR (bracketed expression)
+           **
+           ** Return an error in either case.
+           */
+          if( pPrev && (
+            (eType==FTSQUERY_NEAR && !isPhrase && pPrev->eType!=FTSQUERY_PHRASE)
+         || (eType!=FTSQUERY_PHRASE && isPhrase && pPrev->eType==FTSQUERY_NEAR)
+          )){
+            sqlite3Fts3ExprFree(p);
+            rc = SQLITE_ERROR;
+            goto exprparse_out;
+          }
+
+          if( isPhrase ){
+            if( pRet ){
+              assert( pPrev && pPrev->pLeft && pPrev->pRight==0 );
+              pPrev->pRight = p;
+              p->pParent = pPrev;
+            }else{
+              pRet = p;
+            }
+          }else{
+            insertBinaryOperator(&pRet, pPrev, p);
+          }
+          isRequirePhrase = !isPhrase;
+        }
+        pPrev = p;
+      }
+      assert( nByte>0 );
+    }
+    assert( rc!=SQLITE_OK || (nByte>0 && nByte<=nIn) );
+    nIn -= nByte;
+    zIn += nByte;
+  }
+
+  if( rc==SQLITE_DONE && pRet && isRequirePhrase ){
+    rc = SQLITE_ERROR;
+  }
+
+  if( rc==SQLITE_DONE ){
+    rc = SQLITE_OK;
+    if( !sqlite3_fts3_enable_parentheses && pNotBranch ){
+      if( !pRet ){
+        rc = SQLITE_ERROR;
+      }else{
+        Fts3Expr *pIter = pNotBranch;
+        while( pIter->pLeft ){
+          pIter = pIter->pLeft;
+        }
+        pIter->pLeft = pRet;
+        pRet->pParent = pIter;
+        pRet = pNotBranch;
+      }
+    }
+  }
+  *pnConsumed = n - nIn;
+
+exprparse_out:
+  if( rc!=SQLITE_OK ){
+    sqlite3Fts3ExprFree(pRet);
+    sqlite3Fts3ExprFree(pNotBranch);
+    pRet = 0;
+  }
+  *ppExpr = pRet;
+  return rc;
+}
+
+/*
+** Return SQLITE_ERROR if the maximum depth of the expression tree passed
+** as the only argument is more than nMaxDepth.
+*/
+static int fts3ExprCheckDepth(Fts3Expr *p, int nMaxDepth){
+  int rc = SQLITE_OK;
+  if( p ){
+    if( nMaxDepth<0 ){
+      rc = SQLITE_TOOBIG;
+    }else{
+      rc = fts3ExprCheckDepth(p->pLeft, nMaxDepth-1);
+      if( rc==SQLITE_OK ){
+        rc = fts3ExprCheckDepth(p->pRight, nMaxDepth-1);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** This function attempts to transform the expression tree at (*pp) to
+** an equivalent but more balanced form. The tree is modified in place.
+** If successful, SQLITE_OK is returned and (*pp) set to point to the
+** new root expression node.
+**
+** nMaxDepth is the maximum allowable depth of the balanced sub-tree.
+**
+** Otherwise, if an error occurs, an SQLite error code is returned and
+** expression (*pp) freed.
+*/
+static int fts3ExprBalance(Fts3Expr **pp, int nMaxDepth){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts3Expr *pRoot = *pp;          /* Initial root node */
+  Fts3Expr *pFree = 0;            /* List of free nodes. Linked by pParent. */
+  int eType = pRoot->eType;       /* Type of node in this tree */
+
+  if( nMaxDepth==0 ){
+    rc = SQLITE_ERROR;
+  }
+
+  if( rc==SQLITE_OK ){
+    if( (eType==FTSQUERY_AND || eType==FTSQUERY_OR) ){
+      Fts3Expr **apLeaf;
+      apLeaf = (Fts3Expr **)sqlite3_malloc64(sizeof(Fts3Expr *) * nMaxDepth);
+      if( 0==apLeaf ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(apLeaf, 0, sizeof(Fts3Expr *) * nMaxDepth);
+      }
+
+      if( rc==SQLITE_OK ){
+        int i;
+        Fts3Expr *p;
+
+        /* Set $p to point to the left-most leaf in the tree of eType nodes. */
+        for(p=pRoot; p->eType==eType; p=p->pLeft){
+          assert( p->pParent==0 || p->pParent->pLeft==p );
+          assert( p->pLeft && p->pRight );
+        }
+
+        /* This loop runs once for each leaf in the tree of eType nodes. */
+        while( 1 ){
+          int iLvl;
+          Fts3Expr *pParent = p->pParent;     /* Current parent of p */
+
+          assert( pParent==0 || pParent->pLeft==p );
+          p->pParent = 0;
+          if( pParent ){
+            pParent->pLeft = 0;
+          }else{
+            pRoot = 0;
+          }
+          rc = fts3ExprBalance(&p, nMaxDepth-1);
+          if( rc!=SQLITE_OK ) break;
+
+          for(iLvl=0; p && iLvl<nMaxDepth; iLvl++){
+            if( apLeaf[iLvl]==0 ){
+              apLeaf[iLvl] = p;
+              p = 0;
+            }else{
+              assert( pFree );
+              pFree->pLeft = apLeaf[iLvl];
+              pFree->pRight = p;
+              pFree->pLeft->pParent = pFree;
+              pFree->pRight->pParent = pFree;
+
+              p = pFree;
+              pFree = pFree->pParent;
+              p->pParent = 0;
+              apLeaf[iLvl] = 0;
+            }
+          }
+          if( p ){
+            sqlite3Fts3ExprFree(p);
+            rc = SQLITE_TOOBIG;
+            break;
+          }
+
+          /* If that was the last leaf node, break out of the loop */
+          if( pParent==0 ) break;
+
+          /* Set $p to point to the next leaf in the tree of eType nodes */
+          for(p=pParent->pRight; p->eType==eType; p=p->pLeft);
+
+          /* Remove pParent from the original tree. */
+          assert( pParent->pParent==0 || pParent->pParent->pLeft==pParent );
+          pParent->pRight->pParent = pParent->pParent;
+          if( pParent->pParent ){
+            pParent->pParent->pLeft = pParent->pRight;
+          }else{
+            assert( pParent==pRoot );
+            pRoot = pParent->pRight;
+          }
+
+          /* Link pParent into the free node list. It will be used as an
+          ** internal node of the new tree.  */
+          pParent->pParent = pFree;
+          pFree = pParent;
+        }
+
+        if( rc==SQLITE_OK ){
+          p = 0;
+          for(i=0; i<nMaxDepth; i++){
+            if( apLeaf[i] ){
+              if( p==0 ){
+                p = apLeaf[i];
+                p->pParent = 0;
+              }else{
+                assert( pFree!=0 );
+                pFree->pRight = p;
+                pFree->pLeft = apLeaf[i];
+                pFree->pLeft->pParent = pFree;
+                pFree->pRight->pParent = pFree;
+
+                p = pFree;
+                pFree = pFree->pParent;
+                p->pParent = 0;
+              }
+            }
+          }
+          pRoot = p;
+        }else{
+          /* An error occurred. Delete the contents of the apLeaf[] array
+          ** and pFree list. Everything else is cleaned up by the call to
+          ** sqlite3Fts3ExprFree(pRoot) below.  */
+          Fts3Expr *pDel;
+          for(i=0; i<nMaxDepth; i++){
+            sqlite3Fts3ExprFree(apLeaf[i]);
+          }
+          while( (pDel=pFree)!=0 ){
+            pFree = pDel->pParent;
+            sqlite3_free(pDel);
+          }
+        }
+
+        assert( pFree==0 );
+        sqlite3_free( apLeaf );
+      }
+    }else if( eType==FTSQUERY_NOT ){
+      Fts3Expr *pLeft = pRoot->pLeft;
+      Fts3Expr *pRight = pRoot->pRight;
+
+      pRoot->pLeft = 0;
+      pRoot->pRight = 0;
+      pLeft->pParent = 0;
+      pRight->pParent = 0;
+
+      rc = fts3ExprBalance(&pLeft, nMaxDepth-1);
+      if( rc==SQLITE_OK ){
+        rc = fts3ExprBalance(&pRight, nMaxDepth-1);
+      }
+
+      if( rc!=SQLITE_OK ){
+        sqlite3Fts3ExprFree(pRight);
+        sqlite3Fts3ExprFree(pLeft);
+      }else{
+        assert( pLeft && pRight );
+        pRoot->pLeft = pLeft;
+        pLeft->pParent = pRoot;
+        pRoot->pRight = pRight;
+        pRight->pParent = pRoot;
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3Fts3ExprFree(pRoot);
+    pRoot = 0;
+  }
+  *pp = pRoot;
+  return rc;
+}
+
+/*
+** This function is similar to sqlite3Fts3ExprParse(), with the following
+** differences:
+**
+**   1. It does not do expression rebalancing.
+**   2. It does not check that the expression does not exceed the
+**      maximum allowable depth.
+**   3. Even if it fails, *ppExpr may still be set to point to an
+**      expression tree. It should be deleted using sqlite3Fts3ExprFree()
+**      in this case.
+*/
+static int fts3ExprParseUnbalanced(
+  sqlite3_tokenizer *pTokenizer,      /* Tokenizer module */
+  int iLangid,                        /* Language id for tokenizer */
+  char **azCol,                       /* Array of column names for fts3 table */
+  int bFts4,                          /* True to allow FTS4-only syntax */
+  int nCol,                           /* Number of entries in azCol[] */
+  int iDefaultCol,                    /* Default column to query */
+  const char *z, int n,               /* Text of MATCH query */
+  Fts3Expr **ppExpr                   /* OUT: Parsed query structure */
+){
+  int nParsed;
+  int rc;
+  ParseContext sParse;
+
+  memset(&sParse, 0, sizeof(ParseContext));
+  sParse.pTokenizer = pTokenizer;
+  sParse.iLangid = iLangid;
+  sParse.azCol = (const char **)azCol;
+  sParse.nCol = nCol;
+  sParse.iDefaultCol = iDefaultCol;
+  sParse.bFts4 = bFts4;
+  if( z==0 ){
+    *ppExpr = 0;
+    return SQLITE_OK;
+  }
+  if( n<0 ){
+    n = (int)strlen(z);
+  }
+  rc = fts3ExprParse(&sParse, z, n, ppExpr, &nParsed);
+  assert( rc==SQLITE_OK || *ppExpr==0 );
+
+  /* Check for mismatched parenthesis */
+  if( rc==SQLITE_OK && sParse.nNest ){
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+/*
+** Parameters z and n contain a pointer to and length of a buffer containing
+** an fts3 query expression, respectively. This function attempts to parse the
+** query expression and create a tree of Fts3Expr structures representing the
+** parsed expression. If successful, *ppExpr is set to point to the head
+** of the parsed expression tree and SQLITE_OK is returned. If an error
+** occurs, either SQLITE_NOMEM (out-of-memory error) or SQLITE_ERROR (parse
+** error) is returned and *ppExpr is set to 0.
+**
+** If parameter n is a negative number, then z is assumed to point to a
+** nul-terminated string and the length is determined using strlen().
+**
+** The first parameter, pTokenizer, is passed the fts3 tokenizer module to
+** use to normalize query tokens while parsing the expression. The azCol[]
+** array, which is assumed to contain nCol entries, should contain the names
+** of each column in the target fts3 table, in order from left to right.
+** Column names must be nul-terminated strings.
+**
+** The iDefaultCol parameter should be passed the index of the table column
+** that appears on the left-hand-side of the MATCH operator (the default
+** column to match against for tokens for which a column name is not explicitly
+** specified as part of the query string), or -1 if tokens may by default
+** match any table column.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ExprParse(
+  sqlite3_tokenizer *pTokenizer,      /* Tokenizer module */
+  int iLangid,                        /* Language id for tokenizer */
+  char **azCol,                       /* Array of column names for fts3 table */
+  int bFts4,                          /* True to allow FTS4-only syntax */
+  int nCol,                           /* Number of entries in azCol[] */
+  int iDefaultCol,                    /* Default column to query */
+  const char *z, int n,               /* Text of MATCH query */
+  Fts3Expr **ppExpr,                  /* OUT: Parsed query structure */
+  char **pzErr                        /* OUT: Error message (sqlite3_malloc) */
+){
+  int rc = fts3ExprParseUnbalanced(
+      pTokenizer, iLangid, azCol, bFts4, nCol, iDefaultCol, z, n, ppExpr
+  );
+
+  /* Rebalance the expression. And check that its depth does not exceed
+  ** SQLITE_FTS3_MAX_EXPR_DEPTH.  */
+  if( rc==SQLITE_OK && *ppExpr ){
+    rc = fts3ExprBalance(ppExpr, SQLITE_FTS3_MAX_EXPR_DEPTH);
+    if( rc==SQLITE_OK ){
+      rc = fts3ExprCheckDepth(*ppExpr, SQLITE_FTS3_MAX_EXPR_DEPTH);
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3Fts3ExprFree(*ppExpr);
+    *ppExpr = 0;
+    if( rc==SQLITE_TOOBIG ){
+      sqlite3Fts3ErrMsg(pzErr,
+          "FTS expression tree is too large (maximum depth %d)",
+          SQLITE_FTS3_MAX_EXPR_DEPTH
+      );
+      rc = SQLITE_ERROR;
+    }else if( rc==SQLITE_ERROR ){
+      sqlite3Fts3ErrMsg(pzErr, "malformed MATCH expression: [%s]", z);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Free a single node of an expression tree.
+*/
+static void fts3FreeExprNode(Fts3Expr *p){
+  assert( p->eType==FTSQUERY_PHRASE || p->pPhrase==0 );
+  sqlite3Fts3EvalPhraseCleanup(p->pPhrase);
+  sqlite3_free(p->aMI);
+  sqlite3_free(p);
+}
+
+/*
+** Free a parsed fts3 query expression allocated by sqlite3Fts3ExprParse().
+**
+** This function would be simpler if it recursively called itself. But
+** that would mean passing a sufficiently large expression to ExprParse()
+** could cause a stack overflow.
+*/
+SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *pDel){
+  Fts3Expr *p;
+  assert( pDel==0 || pDel->pParent==0 );
+  for(p=pDel; p && (p->pLeft||p->pRight); p=(p->pLeft ? p->pLeft : p->pRight)){
+    assert( p->pParent==0 || p==p->pParent->pRight || p==p->pParent->pLeft );
+  }
+  while( p ){
+    Fts3Expr *pParent = p->pParent;
+    fts3FreeExprNode(p);
+    if( pParent && p==pParent->pLeft && pParent->pRight ){
+      p = pParent->pRight;
+      while( p && (p->pLeft || p->pRight) ){
+        assert( p==p->pParent->pRight || p==p->pParent->pLeft );
+        p = (p->pLeft ? p->pLeft : p->pRight);
+      }
+    }else{
+      p = pParent;
+    }
+  }
+}
+
+/****************************************************************************
+*****************************************************************************
+** Everything after this point is just test code.
+*/
+
+#ifdef SQLITE_TEST
+
+/* #include <stdio.h> */
+
+/*
+** Return a pointer to a buffer containing a text representation of the
+** expression passed as the first argument. The buffer is obtained from
+** sqlite3_malloc(). It is the responsibility of the caller to use
+** sqlite3_free() to release the memory. If an OOM condition is encountered,
+** NULL is returned.
+**
+** If the second argument is not NULL, then its contents are prepended to
+** the returned expression text and then freed using sqlite3_free().
+*/
+static char *exprToString(Fts3Expr *pExpr, char *zBuf){
+  if( pExpr==0 ){
+    return sqlite3_mprintf("");
+  }
+  switch( pExpr->eType ){
+    case FTSQUERY_PHRASE: {
+      Fts3Phrase *pPhrase = pExpr->pPhrase;
+      int i;
+      zBuf = sqlite3_mprintf(
+          "%zPHRASE %d 0", zBuf, pPhrase->iColumn);
+      for(i=0; zBuf && i<pPhrase->nToken; i++){
+        zBuf = sqlite3_mprintf("%z %.*s%s", zBuf,
+            pPhrase->aToken[i].n, pPhrase->aToken[i].z,
+            (pPhrase->aToken[i].isPrefix?"+":"")
+        );
+      }
+      return zBuf;
+    }
+
+    case FTSQUERY_NEAR:
+      zBuf = sqlite3_mprintf("%zNEAR/%d ", zBuf, pExpr->nNear);
+      break;
+    case FTSQUERY_NOT:
+      zBuf = sqlite3_mprintf("%zNOT ", zBuf);
+      break;
+    case FTSQUERY_AND:
+      zBuf = sqlite3_mprintf("%zAND ", zBuf);
+      break;
+    case FTSQUERY_OR:
+      zBuf = sqlite3_mprintf("%zOR ", zBuf);
+      break;
+  }
+
+  if( zBuf ) zBuf = sqlite3_mprintf("%z{", zBuf);
+  if( zBuf ) zBuf = exprToString(pExpr->pLeft, zBuf);
+  if( zBuf ) zBuf = sqlite3_mprintf("%z} {", zBuf);
+
+  if( zBuf ) zBuf = exprToString(pExpr->pRight, zBuf);
+  if( zBuf ) zBuf = sqlite3_mprintf("%z}", zBuf);
+
+  return zBuf;
+}
+
+/*
+** This is the implementation of a scalar SQL function used to test the
+** expression parser. It should be called as follows:
+**
+**   fts3_exprtest(<tokenizer>, <expr>, <column 1>, ...);
+**
+** The first argument, <tokenizer>, is the name of the fts3 tokenizer used
+** to parse the query expression (see README.tokenizers). The second argument
+** is the query expression to parse. Each subsequent argument is the name
+** of a column of the fts3 table that the query expression may refer to.
+** For example:
+**
+**   SELECT fts3_exprtest('simple', 'Bill col2:Bloggs', 'col1', 'col2');
+*/
+static void fts3ExprTestCommon(
+  int bRebalance,
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_tokenizer *pTokenizer = 0;
+  int rc;
+  char **azCol = 0;
+  const char *zExpr;
+  int nExpr;
+  int nCol;
+  int ii;
+  Fts3Expr *pExpr;
+  char *zBuf = 0;
+  Fts3Hash *pHash = (Fts3Hash*)sqlite3_user_data(context);
+  const char *zTokenizer = 0;
+  char *zErr = 0;
+
+  if( argc<3 ){
+    sqlite3_result_error(context,
+        "Usage: fts3_exprtest(tokenizer, expr, col1, ...", -1
+    );
+    return;
+  }
+
+  zTokenizer = (const char*)sqlite3_value_text(argv[0]);
+  rc = sqlite3Fts3InitTokenizer(pHash, zTokenizer, &pTokenizer, &zErr);
+  if( rc!=SQLITE_OK ){
+    if( rc==SQLITE_NOMEM ){
+      sqlite3_result_error_nomem(context);
+    }else{
+      sqlite3_result_error(context, zErr, -1);
+    }
+    sqlite3_free(zErr);
+    return;
+  }
+
+  zExpr = (const char *)sqlite3_value_text(argv[1]);
+  nExpr = sqlite3_value_bytes(argv[1]);
+  nCol = argc-2;
+  azCol = (char **)sqlite3_malloc64(nCol*sizeof(char *));
+  if( !azCol ){
+    sqlite3_result_error_nomem(context);
+    goto exprtest_out;
+  }
+  for(ii=0; ii<nCol; ii++){
+    azCol[ii] = (char *)sqlite3_value_text(argv[ii+2]);
+  }
+
+  if( bRebalance ){
+    char *zDummy = 0;
+    rc = sqlite3Fts3ExprParse(
+        pTokenizer, 0, azCol, 0, nCol, nCol, zExpr, nExpr, &pExpr, &zDummy
+    );
+    assert( rc==SQLITE_OK || pExpr==0 );
+    sqlite3_free(zDummy);
+  }else{
+    rc = fts3ExprParseUnbalanced(
+        pTokenizer, 0, azCol, 0, nCol, nCol, zExpr, nExpr, &pExpr
+    );
+  }
+
+  if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM ){
+    sqlite3Fts3ExprFree(pExpr);
+    sqlite3_result_error(context, "Error parsing expression", -1);
+  }else if( rc==SQLITE_NOMEM || !(zBuf = exprToString(pExpr, 0)) ){
+    sqlite3_result_error_nomem(context);
+  }else{
+    sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+    sqlite3_free(zBuf);
+  }
+
+  sqlite3Fts3ExprFree(pExpr);
+
+exprtest_out:
+  if( pTokenizer ){
+    rc = pTokenizer->pModule->xDestroy(pTokenizer);
+  }
+  sqlite3_free(azCol);
+}
+
+static void fts3ExprTest(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  fts3ExprTestCommon(0, context, argc, argv);
+}
+static void fts3ExprTestRebalance(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  fts3ExprTestCommon(1, context, argc, argv);
+}
+
+/*
+** Register the query expression parser test function fts3_exprtest()
+** with database connection db.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ExprInitTestInterface(sqlite3 *db, Fts3Hash *pHash){
+  int rc = sqlite3_create_function(
+      db, "fts3_exprtest", -1, SQLITE_UTF8, (void*)pHash, fts3ExprTest, 0, 0
+  );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(db, "fts3_exprtest_rebalance",
+        -1, SQLITE_UTF8, (void*)pHash, fts3ExprTestRebalance, 0, 0
+    );
+  }
+  return rc;
+}
+
+#endif
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_expr.c *******************************************/
+/************** Begin file fts3_hash.c ***************************************/
+/*
+** 2001 September 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This is the implementation of generic hash-tables used in SQLite.
+** We've modified it slightly to serve as a standalone hash table
+** implementation for the full-text indexing module.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <string.h> */
+
+/* #include "fts3_hash.h" */
+
+/*
+** Malloc and Free functions
+*/
+static void *fts3HashMalloc(sqlite3_int64 n){
+  void *p = sqlite3_malloc64(n);
+  if( p ){
+    memset(p, 0, n);
+  }
+  return p;
+}
+static void fts3HashFree(void *p){
+  sqlite3_free(p);
+}
+
+/* Turn bulk memory into a hash table object by initializing the
+** fields of the Hash structure.
+**
+** "pNew" is a pointer to the hash table that is to be initialized.
+** keyClass is one of the constants
+** FTS3_HASH_BINARY or FTS3_HASH_STRING.  The value of keyClass
+** determines what kind of key the hash table will use.  "copyKey" is
+** true if the hash table should make its own private copy of keys and
+** false if it should just use the supplied pointer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashInit(Fts3Hash *pNew, char keyClass, char copyKey){
+  assert( pNew!=0 );
+  assert( keyClass>=FTS3_HASH_STRING && keyClass<=FTS3_HASH_BINARY );
+  pNew->keyClass = keyClass;
+  pNew->copyKey = copyKey;
+  pNew->first = 0;
+  pNew->count = 0;
+  pNew->htsize = 0;
+  pNew->ht = 0;
+}
+
+/* Remove all entries from a hash table.  Reclaim all memory.
+** Call this routine to delete a hash table or to reset a hash table
+** to the empty state.
+*/
+SQLITE_PRIVATE void sqlite3Fts3HashClear(Fts3Hash *pH){
+  Fts3HashElem *elem;         /* For looping over all elements of the table */
+
+  assert( pH!=0 );
+  elem = pH->first;
+  pH->first = 0;
+  fts3HashFree(pH->ht);
+  pH->ht = 0;
+  pH->htsize = 0;
+  while( elem ){
+    Fts3HashElem *next_elem = elem->next;
+    if( pH->copyKey && elem->pKey ){
+      fts3HashFree(elem->pKey);
+    }
+    fts3HashFree(elem);
+    elem = next_elem;
+  }
+  pH->count = 0;
+}
+
+/*
+** Hash and comparison functions when the mode is FTS3_HASH_STRING
+*/
+static int fts3StrHash(const void *pKey, int nKey){
+  const char *z = (const char *)pKey;
+  unsigned h = 0;
+  if( nKey<=0 ) nKey = (int) strlen(z);
+  while( nKey > 0  ){
+    h = (h<<3) ^ h ^ *z++;
+    nKey--;
+  }
+  return (int)(h & 0x7fffffff);
+}
+static int fts3StrCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  if( n1!=n2 ) return 1;
+  return strncmp((const char*)pKey1,(const char*)pKey2,n1);
+}
+
+/*
+** Hash and comparison functions when the mode is FTS3_HASH_BINARY
+*/
+static int fts3BinHash(const void *pKey, int nKey){
+  int h = 0;
+  const char *z = (const char *)pKey;
+  while( nKey-- > 0 ){
+    h = (h<<3) ^ h ^ *(z++);
+  }
+  return h & 0x7fffffff;
+}
+static int fts3BinCompare(const void *pKey1, int n1, const void *pKey2, int n2){
+  if( n1!=n2 ) return 1;
+  return memcmp(pKey1,pKey2,n1);
+}
+
+/*
+** Return a pointer to the appropriate hash function given the key class.
+**
+** The C syntax in this function definition may be unfamilar to some
+** programmers, so we provide the following additional explanation:
+**
+** The name of the function is "ftsHashFunction".  The function takes a
+** single parameter "keyClass".  The return value of ftsHashFunction()
+** is a pointer to another function.  Specifically, the return value
+** of ftsHashFunction() is a pointer to a function that takes two parameters
+** with types "const void*" and "int" and returns an "int".
+*/
+static int (*ftsHashFunction(int keyClass))(const void*,int){
+  if( keyClass==FTS3_HASH_STRING ){
+    return &fts3StrHash;
+  }else{
+    assert( keyClass==FTS3_HASH_BINARY );
+    return &fts3BinHash;
+  }
+}
+
+/*
+** Return a pointer to the appropriate hash function given the key class.
+**
+** For help in interpreted the obscure C code in the function definition,
+** see the header comment on the previous function.
+*/
+static int (*ftsCompareFunction(int keyClass))(const void*,int,const void*,int){
+  if( keyClass==FTS3_HASH_STRING ){
+    return &fts3StrCompare;
+  }else{
+    assert( keyClass==FTS3_HASH_BINARY );
+    return &fts3BinCompare;
+  }
+}
+
+/* Link an element into the hash table
+*/
+static void fts3HashInsertElement(
+  Fts3Hash *pH,            /* The complete hash table */
+  struct _fts3ht *pEntry,  /* The entry into which pNew is inserted */
+  Fts3HashElem *pNew       /* The element to be inserted */
+){
+  Fts3HashElem *pHead;     /* First element already in pEntry */
+  pHead = pEntry->chain;
+  if( pHead ){
+    pNew->next = pHead;
+    pNew->prev = pHead->prev;
+    if( pHead->prev ){ pHead->prev->next = pNew; }
+    else             { pH->first = pNew; }
+    pHead->prev = pNew;
+  }else{
+    pNew->next = pH->first;
+    if( pH->first ){ pH->first->prev = pNew; }
+    pNew->prev = 0;
+    pH->first = pNew;
+  }
+  pEntry->count++;
+  pEntry->chain = pNew;
+}
+
+
+/* Resize the hash table so that it cantains "new_size" buckets.
+** "new_size" must be a power of 2.  The hash table might fail
+** to resize if sqliteMalloc() fails.
+**
+** Return non-zero if a memory allocation error occurs.
+*/
+static int fts3Rehash(Fts3Hash *pH, int new_size){
+  struct _fts3ht *new_ht;          /* The new hash table */
+  Fts3HashElem *elem, *next_elem;  /* For looping over existing elements */
+  int (*xHash)(const void*,int);   /* The hash function */
+
+  assert( (new_size & (new_size-1))==0 );
+  new_ht = (struct _fts3ht *)fts3HashMalloc( new_size*sizeof(struct _fts3ht) );
+  if( new_ht==0 ) return 1;
+  fts3HashFree(pH->ht);
+  pH->ht = new_ht;
+  pH->htsize = new_size;
+  xHash = ftsHashFunction(pH->keyClass);
+  for(elem=pH->first, pH->first=0; elem; elem = next_elem){
+    int h = (*xHash)(elem->pKey, elem->nKey) & (new_size-1);
+    next_elem = elem->next;
+    fts3HashInsertElement(pH, &new_ht[h], elem);
+  }
+  return 0;
+}
+
+/* This function (for internal use only) locates an element in an
+** hash table that matches the given key.  The hash for this key has
+** already been computed and is passed as the 4th parameter.
+*/
+static Fts3HashElem *fts3FindElementByHash(
+  const Fts3Hash *pH, /* The pH to be searched */
+  const void *pKey,   /* The key we are searching for */
+  int nKey,
+  int h               /* The hash for this key. */
+){
+  Fts3HashElem *elem;            /* Used to loop thru the element list */
+  int count;                     /* Number of elements left to test */
+  int (*xCompare)(const void*,int,const void*,int);  /* comparison function */
+
+  if( pH->ht ){
+    struct _fts3ht *pEntry = &pH->ht[h];
+    elem = pEntry->chain;
+    count = pEntry->count;
+    xCompare = ftsCompareFunction(pH->keyClass);
+    while( count-- && elem ){
+      if( (*xCompare)(elem->pKey,elem->nKey,pKey,nKey)==0 ){
+        return elem;
+      }
+      elem = elem->next;
+    }
+  }
+  return 0;
+}
+
+/* Remove a single entry from the hash table given a pointer to that
+** element and a hash on the element's key.
+*/
+static void fts3RemoveElementByHash(
+  Fts3Hash *pH,         /* The pH containing "elem" */
+  Fts3HashElem* elem,   /* The element to be removed from the pH */
+  int h                 /* Hash value for the element */
+){
+  struct _fts3ht *pEntry;
+  if( elem->prev ){
+    elem->prev->next = elem->next;
+  }else{
+    pH->first = elem->next;
+  }
+  if( elem->next ){
+    elem->next->prev = elem->prev;
+  }
+  pEntry = &pH->ht[h];
+  if( pEntry->chain==elem ){
+    pEntry->chain = elem->next;
+  }
+  pEntry->count--;
+  if( pEntry->count<=0 ){
+    pEntry->chain = 0;
+  }
+  if( pH->copyKey && elem->pKey ){
+    fts3HashFree(elem->pKey);
+  }
+  fts3HashFree( elem );
+  pH->count--;
+  if( pH->count<=0 ){
+    assert( pH->first==0 );
+    assert( pH->count==0 );
+    fts3HashClear(pH);
+  }
+}
+
+SQLITE_PRIVATE Fts3HashElem *sqlite3Fts3HashFindElem(
+  const Fts3Hash *pH,
+  const void *pKey,
+  int nKey
+){
+  int h;                          /* A hash on key */
+  int (*xHash)(const void*,int);  /* The hash function */
+
+  if( pH==0 || pH->ht==0 ) return 0;
+  xHash = ftsHashFunction(pH->keyClass);
+  assert( xHash!=0 );
+  h = (*xHash)(pKey,nKey);
+  assert( (pH->htsize & (pH->htsize-1))==0 );
+  return fts3FindElementByHash(pH,pKey,nKey, h & (pH->htsize-1));
+}
+
+/*
+** Attempt to locate an element of the hash table pH with a key
+** that matches pKey,nKey.  Return the data for this element if it is
+** found, or NULL if there is no match.
+*/
+SQLITE_PRIVATE void *sqlite3Fts3HashFind(const Fts3Hash *pH, const void *pKey, int nKey){
+  Fts3HashElem *pElem;            /* The element that matches key (if any) */
+
+  pElem = sqlite3Fts3HashFindElem(pH, pKey, nKey);
+  return pElem ? pElem->data : 0;
+}
+
+/* Insert an element into the hash table pH.  The key is pKey,nKey
+** and the data is "data".
+**
+** If no element exists with a matching key, then a new
+** element is created.  A copy of the key is made if the copyKey
+** flag is set.  NULL is returned.
+**
+** If another element already exists with the same key, then the
+** new data replaces the old data and the old data is returned.
+** The key is not copied in this instance.  If a malloc fails, then
+** the new data is returned and the hash table is unchanged.
+**
+** If the "data" parameter to this function is NULL, then the
+** element corresponding to "key" is removed from the hash table.
+*/
+SQLITE_PRIVATE void *sqlite3Fts3HashInsert(
+  Fts3Hash *pH,        /* The hash table to insert into */
+  const void *pKey,    /* The key */
+  int nKey,            /* Number of bytes in the key */
+  void *data           /* The data */
+){
+  int hraw;                 /* Raw hash value of the key */
+  int h;                    /* the hash of the key modulo hash table size */
+  Fts3HashElem *elem;       /* Used to loop thru the element list */
+  Fts3HashElem *new_elem;   /* New element added to the pH */
+  int (*xHash)(const void*,int);  /* The hash function */
+
+  assert( pH!=0 );
+  xHash = ftsHashFunction(pH->keyClass);
+  assert( xHash!=0 );
+  hraw = (*xHash)(pKey, nKey);
+  assert( (pH->htsize & (pH->htsize-1))==0 );
+  h = hraw & (pH->htsize-1);
+  elem = fts3FindElementByHash(pH,pKey,nKey,h);
+  if( elem ){
+    void *old_data = elem->data;
+    if( data==0 ){
+      fts3RemoveElementByHash(pH,elem,h);
+    }else{
+      elem->data = data;
+    }
+    return old_data;
+  }
+  if( data==0 ) return 0;
+  if( (pH->htsize==0 && fts3Rehash(pH,8))
+   || (pH->count>=pH->htsize && fts3Rehash(pH, pH->htsize*2))
+  ){
+    pH->count = 0;
+    return data;
+  }
+  assert( pH->htsize>0 );
+  new_elem = (Fts3HashElem*)fts3HashMalloc( sizeof(Fts3HashElem) );
+  if( new_elem==0 ) return data;
+  if( pH->copyKey && pKey!=0 ){
+    new_elem->pKey = fts3HashMalloc( nKey );
+    if( new_elem->pKey==0 ){
+      fts3HashFree(new_elem);
+      return data;
+    }
+    memcpy((void*)new_elem->pKey, pKey, nKey);
+  }else{
+    new_elem->pKey = (void*)pKey;
+  }
+  new_elem->nKey = nKey;
+  pH->count++;
+  assert( pH->htsize>0 );
+  assert( (pH->htsize & (pH->htsize-1))==0 );
+  h = hraw & (pH->htsize-1);
+  fts3HashInsertElement(pH, &pH->ht[h], new_elem);
+  new_elem->data = data;
+  return 0;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_hash.c *******************************************/
+/************** Begin file fts3_porter.c *************************************/
+/*
+** 2006 September 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Implementation of the full-text-search tokenizer that implements
+** a Porter stemmer.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+
+/* #include "fts3_tokenizer.h" */
+
+/*
+** Class derived from sqlite3_tokenizer
+*/
+typedef struct porter_tokenizer {
+  sqlite3_tokenizer base;      /* Base class */
+} porter_tokenizer;
+
+/*
+** Class derived from sqlite3_tokenizer_cursor
+*/
+typedef struct porter_tokenizer_cursor {
+  sqlite3_tokenizer_cursor base;
+  const char *zInput;          /* input we are tokenizing */
+  int nInput;                  /* size of the input */
+  int iOffset;                 /* current position in zInput */
+  int iToken;                  /* index of next token to be returned */
+  char *zToken;                /* storage for current token */
+  int nAllocated;              /* space allocated to zToken buffer */
+} porter_tokenizer_cursor;
+
+
+/*
+** Create a new tokenizer instance.
+*/
+static int porterCreate(
+  int argc, const char * const *argv,
+  sqlite3_tokenizer **ppTokenizer
+){
+  porter_tokenizer *t;
+
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+
+  t = (porter_tokenizer *) sqlite3_malloc(sizeof(*t));
+  if( t==NULL ) return SQLITE_NOMEM;
+  memset(t, 0, sizeof(*t));
+  *ppTokenizer = &t->base;
+  return SQLITE_OK;
+}
+
+/*
+** Destroy a tokenizer
+*/
+static int porterDestroy(sqlite3_tokenizer *pTokenizer){
+  sqlite3_free(pTokenizer);
+  return SQLITE_OK;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is zInput[0..nInput-1].  A cursor
+** used to incrementally tokenize this string is returned in
+** *ppCursor.
+*/
+static int porterOpen(
+  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
+  const char *zInput, int nInput,        /* String to be tokenized */
+  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
+){
+  porter_tokenizer_cursor *c;
+
+  UNUSED_PARAMETER(pTokenizer);
+
+  c = (porter_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
+  if( c==NULL ) return SQLITE_NOMEM;
+
+  c->zInput = zInput;
+  if( zInput==0 ){
+    c->nInput = 0;
+  }else if( nInput<0 ){
+    c->nInput = (int)strlen(zInput);
+  }else{
+    c->nInput = nInput;
+  }
+  c->iOffset = 0;                 /* start tokenizing at the beginning */
+  c->iToken = 0;
+  c->zToken = NULL;               /* no space allocated, yet. */
+  c->nAllocated = 0;
+
+  *ppCursor = &c->base;
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to
+** porterOpen() above.
+*/
+static int porterClose(sqlite3_tokenizer_cursor *pCursor){
+  porter_tokenizer_cursor *c = (porter_tokenizer_cursor *) pCursor;
+  sqlite3_free(c->zToken);
+  sqlite3_free(c);
+  return SQLITE_OK;
+}
+/*
+** Vowel or consonant
+*/
+static const char cType[] = {
+   0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0,
+   1, 1, 1, 2, 1
+};
+
+/*
+** isConsonant() and isVowel() determine if their first character in
+** the string they point to is a consonant or a vowel, according
+** to Porter ruls.
+**
+** A consonate is any letter other than 'a', 'e', 'i', 'o', or 'u'.
+** 'Y' is a consonant unless it follows another consonant,
+** in which case it is a vowel.
+**
+** In these routine, the letters are in reverse order.  So the 'y' rule
+** is that 'y' is a consonant unless it is followed by another
+** consonent.
+*/
+static int isVowel(const char*);
+static int isConsonant(const char *z){
+  int j;
+  char x = *z;
+  if( x==0 ) return 0;
+  assert( x>='a' && x<='z' );
+  j = cType[x-'a'];
+  if( j<2 ) return j;
+  return z[1]==0 || isVowel(z + 1);
+}
+static int isVowel(const char *z){
+  int j;
+  char x = *z;
+  if( x==0 ) return 0;
+  assert( x>='a' && x<='z' );
+  j = cType[x-'a'];
+  if( j<2 ) return 1-j;
+  return isConsonant(z + 1);
+}
+
+/*
+** Let any sequence of one or more vowels be represented by V and let
+** C be sequence of one or more consonants.  Then every word can be
+** represented as:
+**
+**           [C] (VC){m} [V]
+**
+** In prose:  A word is an optional consonant followed by zero or
+** vowel-consonant pairs followed by an optional vowel.  "m" is the
+** number of vowel consonant pairs.  This routine computes the value
+** of m for the first i bytes of a word.
+**
+** Return true if the m-value for z is 1 or more.  In other words,
+** return true if z contains at least one vowel that is followed
+** by a consonant.
+**
+** In this routine z[] is in reverse order.  So we are really looking
+** for an instance of a consonant followed by a vowel.
+*/
+static int m_gt_0(const char *z){
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  return *z!=0;
+}
+
+/* Like mgt0 above except we are looking for a value of m which is
+** exactly 1
+*/
+static int m_eq_1(const char *z){
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 1;
+  while( isConsonant(z) ){ z++; }
+  return *z==0;
+}
+
+/* Like mgt0 above except we are looking for a value of m>1 instead
+** or m>0
+*/
+static int m_gt_1(const char *z){
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isVowel(z) ){ z++; }
+  if( *z==0 ) return 0;
+  while( isConsonant(z) ){ z++; }
+  return *z!=0;
+}
+
+/*
+** Return TRUE if there is a vowel anywhere within z[0..n-1]
+*/
+static int hasVowel(const char *z){
+  while( isConsonant(z) ){ z++; }
+  return *z!=0;
+}
+
+/*
+** Return TRUE if the word ends in a double consonant.
+**
+** The text is reversed here. So we are really looking at
+** the first two characters of z[].
+*/
+static int doubleConsonant(const char *z){
+  return isConsonant(z) && z[0]==z[1];
+}
+
+/*
+** Return TRUE if the word ends with three letters which
+** are consonant-vowel-consonent and where the final consonant
+** is not 'w', 'x', or 'y'.
+**
+** The word is reversed here.  So we are really checking the
+** first three letters and the first one cannot be in [wxy].
+*/
+static int star_oh(const char *z){
+  return
+    isConsonant(z) &&
+    z[0]!='w' && z[0]!='x' && z[0]!='y' &&
+    isVowel(z+1) &&
+    isConsonant(z+2);
+}
+
+/*
+** If the word ends with zFrom and xCond() is true for the stem
+** of the word that preceeds the zFrom ending, then change the
+** ending to zTo.
+**
+** The input word *pz and zFrom are both in reverse order.  zTo
+** is in normal order.
+**
+** Return TRUE if zFrom matches.  Return FALSE if zFrom does not
+** match.  Not that TRUE is returned even if xCond() fails and
+** no substitution occurs.
+*/
+static int stem(
+  char **pz,             /* The word being stemmed (Reversed) */
+  const char *zFrom,     /* If the ending matches this... (Reversed) */
+  const char *zTo,       /* ... change the ending to this (not reversed) */
+  int (*xCond)(const char*)   /* Condition that must be true */
+){
+  char *z = *pz;
+  while( *zFrom && *zFrom==*z ){ z++; zFrom++; }
+  if( *zFrom!=0 ) return 0;
+  if( xCond && !xCond(z) ) return 1;
+  while( *zTo ){
+    *(--z) = *(zTo++);
+  }
+  *pz = z;
+  return 1;
+}
+
+/*
+** This is the fallback stemmer used when the porter stemmer is
+** inappropriate.  The input word is copied into the output with
+** US-ASCII case folding.  If the input word is too long (more
+** than 20 bytes if it contains no digits or more than 6 bytes if
+** it contains digits) then word is truncated to 20 or 6 bytes
+** by taking 10 or 3 bytes from the beginning and end.
+*/
+static void copy_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
+  int i, mx, j;
+  int hasDigit = 0;
+  for(i=0; i<nIn; i++){
+    char c = zIn[i];
+    if( c>='A' && c<='Z' ){
+      zOut[i] = c - 'A' + 'a';
+    }else{
+      if( c>='0' && c<='9' ) hasDigit = 1;
+      zOut[i] = c;
+    }
+  }
+  mx = hasDigit ? 3 : 10;
+  if( nIn>mx*2 ){
+    for(j=mx, i=nIn-mx; i<nIn; i++, j++){
+      zOut[j] = zOut[i];
+    }
+    i = j;
+  }
+  zOut[i] = 0;
+  *pnOut = i;
+}
+
+
+/*
+** Stem the input word zIn[0..nIn-1].  Store the output in zOut.
+** zOut is at least big enough to hold nIn bytes.  Write the actual
+** size of the output word (exclusive of the '\0' terminator) into *pnOut.
+**
+** Any upper-case characters in the US-ASCII character set ([A-Z])
+** are converted to lower case.  Upper-case UTF characters are
+** unchanged.
+**
+** Words that are longer than about 20 bytes are stemmed by retaining
+** a few bytes from the beginning and the end of the word.  If the
+** word contains digits, 3 bytes are taken from the beginning and
+** 3 bytes from the end.  For long words without digits, 10 bytes
+** are taken from each end.  US-ASCII case folding still applies.
+**
+** If the input word contains not digits but does characters not
+** in [a-zA-Z] then no stemming is attempted and this routine just
+** copies the input into the input into the output with US-ASCII
+** case folding.
+**
+** Stemming never increases the length of the word.  So there is
+** no chance of overflowing the zOut buffer.
+*/
+static void porter_stemmer(const char *zIn, int nIn, char *zOut, int *pnOut){
+  int i, j;
+  char zReverse[28];
+  char *z, *z2;
+  if( nIn<3 || nIn>=(int)sizeof(zReverse)-7 ){
+    /* The word is too big or too small for the porter stemmer.
+    ** Fallback to the copy stemmer */
+    copy_stemmer(zIn, nIn, zOut, pnOut);
+    return;
+  }
+  for(i=0, j=sizeof(zReverse)-6; i<nIn; i++, j--){
+    char c = zIn[i];
+    if( c>='A' && c<='Z' ){
+      zReverse[j] = c + 'a' - 'A';
+    }else if( c>='a' && c<='z' ){
+      zReverse[j] = c;
+    }else{
+      /* The use of a character not in [a-zA-Z] means that we fallback
+      ** to the copy stemmer */
+      copy_stemmer(zIn, nIn, zOut, pnOut);
+      return;
+    }
+  }
+  memset(&zReverse[sizeof(zReverse)-5], 0, 5);
+  z = &zReverse[j+1];
+
+
+  /* Step 1a */
+  if( z[0]=='s' ){
+    if(
+     !stem(&z, "sess", "ss", 0) &&
+     !stem(&z, "sei", "i", 0)  &&
+     !stem(&z, "ss", "ss", 0)
+    ){
+      z++;
+    }
+  }
+
+  /* Step 1b */
+  z2 = z;
+  if( stem(&z, "dee", "ee", m_gt_0) ){
+    /* Do nothing.  The work was all in the test */
+  }else if(
+     (stem(&z, "gni", "", hasVowel) || stem(&z, "de", "", hasVowel))
+      && z!=z2
+  ){
+     if( stem(&z, "ta", "ate", 0) ||
+         stem(&z, "lb", "ble", 0) ||
+         stem(&z, "zi", "ize", 0) ){
+       /* Do nothing.  The work was all in the test */
+     }else if( doubleConsonant(z) && (*z!='l' && *z!='s' && *z!='z') ){
+       z++;
+     }else if( m_eq_1(z) && star_oh(z) ){
+       *(--z) = 'e';
+     }
+  }
+
+  /* Step 1c */
+  if( z[0]=='y' && hasVowel(z+1) ){
+    z[0] = 'i';
+  }
+
+  /* Step 2 */
+  switch( z[1] ){
+   case 'a':
+     if( !stem(&z, "lanoita", "ate", m_gt_0) ){
+       stem(&z, "lanoit", "tion", m_gt_0);
+     }
+     break;
+   case 'c':
+     if( !stem(&z, "icne", "ence", m_gt_0) ){
+       stem(&z, "icna", "ance", m_gt_0);
+     }
+     break;
+   case 'e':
+     stem(&z, "rezi", "ize", m_gt_0);
+     break;
+   case 'g':
+     stem(&z, "igol", "log", m_gt_0);
+     break;
+   case 'l':
+     if( !stem(&z, "ilb", "ble", m_gt_0)
+      && !stem(&z, "illa", "al", m_gt_0)
+      && !stem(&z, "iltne", "ent", m_gt_0)
+      && !stem(&z, "ile", "e", m_gt_0)
+     ){
+       stem(&z, "ilsuo", "ous", m_gt_0);
+     }
+     break;
+   case 'o':
+     if( !stem(&z, "noitazi", "ize", m_gt_0)
+      && !stem(&z, "noita", "ate", m_gt_0)
+     ){
+       stem(&z, "rota", "ate", m_gt_0);
+     }
+     break;
+   case 's':
+     if( !stem(&z, "msila", "al", m_gt_0)
+      && !stem(&z, "ssenevi", "ive", m_gt_0)
+      && !stem(&z, "ssenluf", "ful", m_gt_0)
+     ){
+       stem(&z, "ssensuo", "ous", m_gt_0);
+     }
+     break;
+   case 't':
+     if( !stem(&z, "itila", "al", m_gt_0)
+      && !stem(&z, "itivi", "ive", m_gt_0)
+     ){
+       stem(&z, "itilib", "ble", m_gt_0);
+     }
+     break;
+  }
+
+  /* Step 3 */
+  switch( z[0] ){
+   case 'e':
+     if( !stem(&z, "etaci", "ic", m_gt_0)
+      && !stem(&z, "evita", "", m_gt_0)
+     ){
+       stem(&z, "ezila", "al", m_gt_0);
+     }
+     break;
+   case 'i':
+     stem(&z, "itici", "ic", m_gt_0);
+     break;
+   case 'l':
+     if( !stem(&z, "laci", "ic", m_gt_0) ){
+       stem(&z, "luf", "", m_gt_0);
+     }
+     break;
+   case 's':
+     stem(&z, "ssen", "", m_gt_0);
+     break;
+  }
+
+  /* Step 4 */
+  switch( z[1] ){
+   case 'a':
+     if( z[0]=='l' && m_gt_1(z+2) ){
+       z += 2;
+     }
+     break;
+   case 'c':
+     if( z[0]=='e' && z[2]=='n' && (z[3]=='a' || z[3]=='e')  && m_gt_1(z+4)  ){
+       z += 4;
+     }
+     break;
+   case 'e':
+     if( z[0]=='r' && m_gt_1(z+2) ){
+       z += 2;
+     }
+     break;
+   case 'i':
+     if( z[0]=='c' && m_gt_1(z+2) ){
+       z += 2;
+     }
+     break;
+   case 'l':
+     if( z[0]=='e' && z[2]=='b' && (z[3]=='a' || z[3]=='i') && m_gt_1(z+4) ){
+       z += 4;
+     }
+     break;
+   case 'n':
+     if( z[0]=='t' ){
+       if( z[2]=='a' ){
+         if( m_gt_1(z+3) ){
+           z += 3;
+         }
+       }else if( z[2]=='e' ){
+         if( !stem(&z, "tneme", "", m_gt_1)
+          && !stem(&z, "tnem", "", m_gt_1)
+         ){
+           stem(&z, "tne", "", m_gt_1);
+         }
+       }
+     }
+     break;
+   case 'o':
+     if( z[0]=='u' ){
+       if( m_gt_1(z+2) ){
+         z += 2;
+       }
+     }else if( z[3]=='s' || z[3]=='t' ){
+       stem(&z, "noi", "", m_gt_1);
+     }
+     break;
+   case 's':
+     if( z[0]=='m' && z[2]=='i' && m_gt_1(z+3) ){
+       z += 3;
+     }
+     break;
+   case 't':
+     if( !stem(&z, "eta", "", m_gt_1) ){
+       stem(&z, "iti", "", m_gt_1);
+     }
+     break;
+   case 'u':
+     if( z[0]=='s' && z[2]=='o' && m_gt_1(z+3) ){
+       z += 3;
+     }
+     break;
+   case 'v':
+   case 'z':
+     if( z[0]=='e' && z[2]=='i' && m_gt_1(z+3) ){
+       z += 3;
+     }
+     break;
+  }
+
+  /* Step 5a */
+  if( z[0]=='e' ){
+    if( m_gt_1(z+1) ){
+      z++;
+    }else if( m_eq_1(z+1) && !star_oh(z+1) ){
+      z++;
+    }
+  }
+
+  /* Step 5b */
+  if( m_gt_1(z) && z[0]=='l' && z[1]=='l' ){
+    z++;
+  }
+
+  /* z[] is now the stemmed word in reverse order.  Flip it back
+  ** around into forward order and return.
+  */
+  *pnOut = i = (int)strlen(z);
+  zOut[i] = 0;
+  while( *z ){
+    zOut[--i] = *(z++);
+  }
+}
+
+/*
+** Characters that can be part of a token.  We assume any character
+** whose value is greater than 0x80 (any UTF character) can be
+** part of a token.  In other words, delimiters all must have
+** values of 0x7f or lower.
+*/
+static const char porterIdChar[] = {
+/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
+    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
+};
+#define isDelim(C) (((ch=C)&0x80)==0 && (ch<0x30 || !porterIdChar[ch-0x30]))
+
+/*
+** Extract the next token from a tokenization cursor.  The cursor must
+** have been opened by a prior call to porterOpen().
+*/
+static int porterNext(
+  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by porterOpen */
+  const char **pzToken,               /* OUT: *pzToken is the token text */
+  int *pnBytes,                       /* OUT: Number of bytes in token */
+  int *piStartOffset,                 /* OUT: Starting offset of token */
+  int *piEndOffset,                   /* OUT: Ending offset of token */
+  int *piPosition                     /* OUT: Position integer of token */
+){
+  porter_tokenizer_cursor *c = (porter_tokenizer_cursor *) pCursor;
+  const char *z = c->zInput;
+
+  while( c->iOffset<c->nInput ){
+    int iStartOffset, ch;
+
+    /* Scan past delimiter characters */
+    while( c->iOffset<c->nInput && isDelim(z[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    /* Count non-delimiter characters. */
+    iStartOffset = c->iOffset;
+    while( c->iOffset<c->nInput && !isDelim(z[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    if( c->iOffset>iStartOffset ){
+      int n = c->iOffset-iStartOffset;
+      if( n>c->nAllocated ){
+        char *pNew;
+        c->nAllocated = n+20;
+        pNew = sqlite3_realloc64(c->zToken, c->nAllocated);
+        if( !pNew ) return SQLITE_NOMEM;
+        c->zToken = pNew;
+      }
+      porter_stemmer(&z[iStartOffset], n, c->zToken, pnBytes);
+      *pzToken = c->zToken;
+      *piStartOffset = iStartOffset;
+      *piEndOffset = c->iOffset;
+      *piPosition = c->iToken++;
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_DONE;
+}
+
+/*
+** The set of routines that implement the porter-stemmer tokenizer
+*/
+static const sqlite3_tokenizer_module porterTokenizerModule = {
+  0,
+  porterCreate,
+  porterDestroy,
+  porterOpen,
+  porterClose,
+  porterNext,
+  0
+};
+
+/*
+** Allocate a new porter tokenizer.  Return a pointer to the new
+** tokenizer in *ppModule
+*/
+SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(
+  sqlite3_tokenizer_module const**ppModule
+){
+  *ppModule = &porterTokenizerModule;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_porter.c *****************************************/
+/************** Begin file fts3_tokenizer.c **********************************/
+/*
+** 2007 June 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is part of an SQLite module implementing full-text search.
+** This particular file implements the generic tokenizer interface.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <string.h> */
+
+/*
+** Return true if the two-argument version of fts3_tokenizer()
+** has been activated via a prior call to sqlite3_db_config(db,
+** SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, 1, 0);
+*/
+static int fts3TokenizerEnabled(sqlite3_context *context){
+  sqlite3 *db = sqlite3_context_db_handle(context);
+  int isEnabled = 0;
+  sqlite3_db_config(db,SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER,-1,&isEnabled);
+  return isEnabled;
+}
+
+/*
+** Implementation of the SQL scalar function for accessing the underlying
+** hash table. This function may be called as follows:
+**
+**   SELECT <function-name>(<key-name>);
+**   SELECT <function-name>(<key-name>, <pointer>);
+**
+** where <function-name> is the name passed as the second argument
+** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer').
+**
+** If the <pointer> argument is specified, it must be a blob value
+** containing a pointer to be stored as the hash data corresponding
+** to the string <key-name>. If <pointer> is not specified, then
+** the string <key-name> must already exist in the has table. Otherwise,
+** an error is returned.
+**
+** Whether or not the <pointer> argument is specified, the value returned
+** is a blob containing the pointer stored as the hash data corresponding
+** to string <key-name> (after the hash-table is updated, if applicable).
+*/
+static void fts3TokenizerFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  Fts3Hash *pHash;
+  void *pPtr = 0;
+  const unsigned char *zName;
+  int nName;
+
+  assert( argc==1 || argc==2 );
+
+  pHash = (Fts3Hash *)sqlite3_user_data(context);
+
+  zName = sqlite3_value_text(argv[0]);
+  nName = sqlite3_value_bytes(argv[0])+1;
+
+  if( argc==2 ){
+    if( fts3TokenizerEnabled(context) || sqlite3_value_frombind(argv[1]) ){
+      void *pOld;
+      int n = sqlite3_value_bytes(argv[1]);
+      if( zName==0 || n!=sizeof(pPtr) ){
+        sqlite3_result_error(context, "argument type mismatch", -1);
+        return;
+      }
+      pPtr = *(void **)sqlite3_value_blob(argv[1]);
+      pOld = sqlite3Fts3HashInsert(pHash, (void *)zName, nName, pPtr);
+      if( pOld==pPtr ){
+        sqlite3_result_error(context, "out of memory", -1);
+      }
+    }else{
+      sqlite3_result_error(context, "fts3tokenize disabled", -1);
+      return;
+    }
+  }else{
+    if( zName ){
+      pPtr = sqlite3Fts3HashFind(pHash, zName, nName);
+    }
+    if( !pPtr ){
+      char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
+      sqlite3_result_error(context, zErr, -1);
+      sqlite3_free(zErr);
+      return;
+    }
+  }
+  if( fts3TokenizerEnabled(context) || sqlite3_value_frombind(argv[0]) ){
+    sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT);
+  }
+}
+
+SQLITE_PRIVATE int sqlite3Fts3IsIdChar(char c){
+  static const char isFtsIdChar[] = {
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 0x */
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 1x */
+      0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
+      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
+      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
+      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
+  };
+  return (c&0x80 || isFtsIdChar[(int)(c)]);
+}
+
+SQLITE_PRIVATE const char *sqlite3Fts3NextToken(const char *zStr, int *pn){
+  const char *z1;
+  const char *z2 = 0;
+
+  /* Find the start of the next token. */
+  z1 = zStr;
+  while( z2==0 ){
+    char c = *z1;
+    switch( c ){
+      case '\0': return 0;        /* No more tokens here */
+      case '\'':
+      case '"':
+      case '`': {
+        z2 = z1;
+        while( *++z2 && (*z2!=c || *++z2==c) );
+        break;
+      }
+      case '[':
+        z2 = &z1[1];
+        while( *z2 && z2[0]!=']' ) z2++;
+        if( *z2 ) z2++;
+        break;
+
+      default:
+        if( sqlite3Fts3IsIdChar(*z1) ){
+          z2 = &z1[1];
+          while( sqlite3Fts3IsIdChar(*z2) ) z2++;
+        }else{
+          z1++;
+        }
+    }
+  }
+
+  *pn = (int)(z2-z1);
+  return z1;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3InitTokenizer(
+  Fts3Hash *pHash,                /* Tokenizer hash table */
+  const char *zArg,               /* Tokenizer name */
+  sqlite3_tokenizer **ppTok,      /* OUT: Tokenizer (if applicable) */
+  char **pzErr                    /* OUT: Set to malloced error message */
+){
+  int rc;
+  char *z = (char *)zArg;
+  int n = 0;
+  char *zCopy;
+  char *zEnd;                     /* Pointer to nul-term of zCopy */
+  sqlite3_tokenizer_module *m;
+
+  zCopy = sqlite3_mprintf("%s", zArg);
+  if( !zCopy ) return SQLITE_NOMEM;
+  zEnd = &zCopy[strlen(zCopy)];
+
+  z = (char *)sqlite3Fts3NextToken(zCopy, &n);
+  if( z==0 ){
+    assert( n==0 );
+    z = zCopy;
+  }
+  z[n] = '\0';
+  sqlite3Fts3Dequote(z);
+
+  m = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash,z,(int)strlen(z)+1);
+  if( !m ){
+    sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer: %s", z);
+    rc = SQLITE_ERROR;
+  }else{
+    char const **aArg = 0;
+    int iArg = 0;
+    z = &z[n+1];
+    while( z<zEnd && (NULL!=(z = (char *)sqlite3Fts3NextToken(z, &n))) ){
+      sqlite3_int64 nNew = sizeof(char *)*(iArg+1);
+      char const **aNew = (const char **)sqlite3_realloc64((void *)aArg, nNew);
+      if( !aNew ){
+        sqlite3_free(zCopy);
+        sqlite3_free((void *)aArg);
+        return SQLITE_NOMEM;
+      }
+      aArg = aNew;
+      aArg[iArg++] = z;
+      z[n] = '\0';
+      sqlite3Fts3Dequote(z);
+      z = &z[n+1];
+    }
+    rc = m->xCreate(iArg, aArg, ppTok);
+    assert( rc!=SQLITE_OK || *ppTok );
+    if( rc!=SQLITE_OK ){
+      sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer");
+    }else{
+      (*ppTok)->pModule = m;
+    }
+    sqlite3_free((void *)aArg);
+  }
+
+  sqlite3_free(zCopy);
+  return rc;
+}
+
+
+#ifdef SQLITE_TEST
+
+#include "tclsqlite.h"
+/* #include <string.h> */
+
+/*
+** Implementation of a special SQL scalar function for testing tokenizers
+** designed to be used in concert with the Tcl testing framework. This
+** function must be called with two or more arguments:
+**
+**   SELECT <function-name>(<key-name>, ..., <input-string>);
+**
+** where <function-name> is the name passed as the second argument
+** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer')
+** concatenated with the string '_test' (e.g. 'fts3_tokenizer_test').
+**
+** The return value is a string that may be interpreted as a Tcl
+** list. For each token in the <input-string>, three elements are
+** added to the returned list. The first is the token position, the
+** second is the token text (folded, stemmed, etc.) and the third is the
+** substring of <input-string> associated with the token. For example,
+** using the built-in "simple" tokenizer:
+**
+**   SELECT fts_tokenizer_test('simple', 'I don't see how');
+**
+** will return the string:
+**
+**   "{0 i I 1 dont don't 2 see see 3 how how}"
+**
+*/
+static void testFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  Fts3Hash *pHash;
+  sqlite3_tokenizer_module *p;
+  sqlite3_tokenizer *pTokenizer = 0;
+  sqlite3_tokenizer_cursor *pCsr = 0;
+
+  const char *zErr = 0;
+
+  const char *zName;
+  int nName;
+  const char *zInput;
+  int nInput;
+
+  const char *azArg[64];
+
+  const char *zToken;
+  int nToken = 0;
+  int iStart = 0;
+  int iEnd = 0;
+  int iPos = 0;
+  int i;
+
+  Tcl_Obj *pRet;
+
+  if( argc<2 ){
+    sqlite3_result_error(context, "insufficient arguments", -1);
+    return;
+  }
+
+  nName = sqlite3_value_bytes(argv[0]);
+  zName = (const char *)sqlite3_value_text(argv[0]);
+  nInput = sqlite3_value_bytes(argv[argc-1]);
+  zInput = (const char *)sqlite3_value_text(argv[argc-1]);
+
+  pHash = (Fts3Hash *)sqlite3_user_data(context);
+  p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
+
+  if( !p ){
+    char *zErr2 = sqlite3_mprintf("unknown tokenizer: %s", zName);
+    sqlite3_result_error(context, zErr2, -1);
+    sqlite3_free(zErr2);
+    return;
+  }
+
+  pRet = Tcl_NewObj();
+  Tcl_IncrRefCount(pRet);
+
+  for(i=1; i<argc-1; i++){
+    azArg[i-1] = (const char *)sqlite3_value_text(argv[i]);
+  }
+
+  if( SQLITE_OK!=p->xCreate(argc-2, azArg, &pTokenizer) ){
+    zErr = "error in xCreate()";
+    goto finish;
+  }
+  pTokenizer->pModule = p;
+  if( sqlite3Fts3OpenTokenizer(pTokenizer, 0, zInput, nInput, &pCsr) ){
+    zErr = "error in xOpen()";
+    goto finish;
+  }
+
+  while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){
+    Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos));
+    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
+    zToken = &zInput[iStart];
+    nToken = iEnd-iStart;
+    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
+  }
+
+  if( SQLITE_OK!=p->xClose(pCsr) ){
+    zErr = "error in xClose()";
+    goto finish;
+  }
+  if( SQLITE_OK!=p->xDestroy(pTokenizer) ){
+    zErr = "error in xDestroy()";
+    goto finish;
+  }
+
+finish:
+  if( zErr ){
+    sqlite3_result_error(context, zErr, -1);
+  }else{
+    sqlite3_result_text(context, Tcl_GetString(pRet), -1, SQLITE_TRANSIENT);
+  }
+  Tcl_DecrRefCount(pRet);
+}
+
+static
+int registerTokenizer(
+  sqlite3 *db,
+  char *zName,
+  const sqlite3_tokenizer_module *p
+){
+  int rc;
+  sqlite3_stmt *pStmt;
+  const char zSql[] = "SELECT fts3_tokenizer(?, ?)";
+
+  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
+  sqlite3_bind_blob(pStmt, 2, &p, sizeof(p), SQLITE_STATIC);
+  sqlite3_step(pStmt);
+
+  return sqlite3_finalize(pStmt);
+}
+
+
+static
+int queryTokenizer(
+  sqlite3 *db,
+  char *zName,
+  const sqlite3_tokenizer_module **pp
+){
+  int rc;
+  sqlite3_stmt *pStmt;
+  const char zSql[] = "SELECT fts3_tokenizer(?)";
+
+  *pp = 0;
+  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB
+     && sqlite3_column_bytes(pStmt, 0)==sizeof(*pp)
+    ){
+      memcpy((void *)pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
+    }
+  }
+
+  return sqlite3_finalize(pStmt);
+}
+
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+
+/*
+** Implementation of the scalar function fts3_tokenizer_internal_test().
+** This function is used for testing only, it is not included in the
+** build unless SQLITE_TEST is defined.
+**
+** The purpose of this is to test that the fts3_tokenizer() function
+** can be used as designed by the C-code in the queryTokenizer and
+** registerTokenizer() functions above. These two functions are repeated
+** in the README.tokenizer file as an example, so it is important to
+** test them.
+**
+** To run the tests, evaluate the fts3_tokenizer_internal_test() scalar
+** function with no arguments. An assert() will fail if a problem is
+** detected. i.e.:
+**
+**     SELECT fts3_tokenizer_internal_test();
+**
+*/
+static void intTestFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  int rc;
+  const sqlite3_tokenizer_module *p1;
+  const sqlite3_tokenizer_module *p2;
+  sqlite3 *db = (sqlite3 *)sqlite3_user_data(context);
+
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+
+  /* Test the query function */
+  sqlite3Fts3SimpleTokenizerModule(&p1);
+  rc = queryTokenizer(db, "simple", &p2);
+  assert( rc==SQLITE_OK );
+  assert( p1==p2 );
+  rc = queryTokenizer(db, "nosuchtokenizer", &p2);
+  assert( rc==SQLITE_ERROR );
+  assert( p2==0 );
+  assert( 0==strcmp(sqlite3_errmsg(db), "unknown tokenizer: nosuchtokenizer") );
+
+  /* Test the storage function */
+  if( fts3TokenizerEnabled(context) ){
+    rc = registerTokenizer(db, "nosuchtokenizer", p1);
+    assert( rc==SQLITE_OK );
+    rc = queryTokenizer(db, "nosuchtokenizer", &p2);
+    assert( rc==SQLITE_OK );
+    assert( p2==p1 );
+  }
+
+  sqlite3_result_text(context, "ok", -1, SQLITE_STATIC);
+}
+
+#endif
+
+/*
+** Set up SQL objects in database db used to access the contents of
+** the hash table pointed to by argument pHash. The hash table must
+** been initialized to use string keys, and to take a private copy
+** of the key when a value is inserted. i.e. by a call similar to:
+**
+**    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
+**
+** This function adds a scalar function (see header comment above
+** fts3TokenizerFunc() in this file for details) and, if ENABLE_TABLE is
+** defined at compilation time, a temporary virtual table (see header
+** comment above struct HashTableVtab) to the database schema. Both
+** provide read/write access to the contents of *pHash.
+**
+** The third argument to this function, zName, is used as the name
+** of both the scalar and, if created, the virtual table.
+*/
+SQLITE_PRIVATE int sqlite3Fts3InitHashTable(
+  sqlite3 *db,
+  Fts3Hash *pHash,
+  const char *zName
+){
+  int rc = SQLITE_OK;
+  void *p = (void *)pHash;
+  const int any = SQLITE_UTF8|SQLITE_DIRECTONLY;
+
+#ifdef SQLITE_TEST
+  char *zTest = 0;
+  char *zTest2 = 0;
+  void *pdb = (void *)db;
+  zTest = sqlite3_mprintf("%s_test", zName);
+  zTest2 = sqlite3_mprintf("%s_internal_test", zName);
+  if( !zTest || !zTest2 ){
+    rc = SQLITE_NOMEM;
+  }
+#endif
+
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zName, 1, any, p, fts3TokenizerFunc, 0, 0);
+  }
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zName, 2, any, p, fts3TokenizerFunc, 0, 0);
+  }
+#ifdef SQLITE_TEST
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zTest, -1, any, p, testFunc, 0, 0);
+  }
+  if( SQLITE_OK==rc ){
+    rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0);
+  }
+#endif
+
+#ifdef SQLITE_TEST
+  sqlite3_free(zTest);
+  sqlite3_free(zTest2);
+#endif
+
+  return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_tokenizer.c **************************************/
+/************** Begin file fts3_tokenizer1.c *********************************/
+/*
+** 2006 Oct 10
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Implementation of the "simple" full-text-search tokenizer.
+*/
+
+/*
+** The code in this file is only compiled if:
+**
+**     * The FTS3 module is being built as an extension
+**       (in which case SQLITE_CORE is not defined), or
+**
+**     * The FTS3 module is being built into the core of
+**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+
+/* #include "fts3_tokenizer.h" */
+
+typedef struct simple_tokenizer {
+  sqlite3_tokenizer base;
+  char delim[128];             /* flag ASCII delimiters */
+} simple_tokenizer;
+
+typedef struct simple_tokenizer_cursor {
+  sqlite3_tokenizer_cursor base;
+  const char *pInput;          /* input we are tokenizing */
+  int nBytes;                  /* size of the input */
+  int iOffset;                 /* current position in pInput */
+  int iToken;                  /* index of next token to be returned */
+  char *pToken;                /* storage for current token */
+  int nTokenAllocated;         /* space allocated to zToken buffer */
+} simple_tokenizer_cursor;
+
+
+static int simpleDelim(simple_tokenizer *t, unsigned char c){
+  return c<0x80 && t->delim[c];
+}
+static int fts3_isalnum(int x){
+  return (x>='0' && x<='9') || (x>='A' && x<='Z') || (x>='a' && x<='z');
+}
+
+/*
+** Create a new tokenizer instance.
+*/
+static int simpleCreate(
+  int argc, const char * const *argv,
+  sqlite3_tokenizer **ppTokenizer
+){
+  simple_tokenizer *t;
+
+  t = (simple_tokenizer *) sqlite3_malloc(sizeof(*t));
+  if( t==NULL ) return SQLITE_NOMEM;
+  memset(t, 0, sizeof(*t));
+
+  /* TODO(shess) Delimiters need to remain the same from run to run,
+  ** else we need to reindex.  One solution would be a meta-table to
+  ** track such information in the database, then we'd only want this
+  ** information on the initial create.
+  */
+  if( argc>1 ){
+    int i, n = (int)strlen(argv[1]);
+    for(i=0; i<n; i++){
+      unsigned char ch = argv[1][i];
+      /* We explicitly don't support UTF-8 delimiters for now. */
+      if( ch>=0x80 ){
+        sqlite3_free(t);
+        return SQLITE_ERROR;
+      }
+      t->delim[ch] = 1;
+    }
+  } else {
+    /* Mark non-alphanumeric ASCII characters as delimiters */
+    int i;
+    for(i=1; i<0x80; i++){
+      t->delim[i] = !fts3_isalnum(i) ? -1 : 0;
+    }
+  }
+
+  *ppTokenizer = &t->base;
+  return SQLITE_OK;
+}
+
+/*
+** Destroy a tokenizer
+*/
+static int simpleDestroy(sqlite3_tokenizer *pTokenizer){
+  sqlite3_free(pTokenizer);
+  return SQLITE_OK;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is pInput[0..nBytes-1].  A cursor
+** used to incrementally tokenize this string is returned in
+** *ppCursor.
+*/
+static int simpleOpen(
+  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
+  const char *pInput, int nBytes,        /* String to be tokenized */
+  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
+){
+  simple_tokenizer_cursor *c;
+
+  UNUSED_PARAMETER(pTokenizer);
+
+  c = (simple_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
+  if( c==NULL ) return SQLITE_NOMEM;
+
+  c->pInput = pInput;
+  if( pInput==0 ){
+    c->nBytes = 0;
+  }else if( nBytes<0 ){
+    c->nBytes = (int)strlen(pInput);
+  }else{
+    c->nBytes = nBytes;
+  }
+  c->iOffset = 0;                 /* start tokenizing at the beginning */
+  c->iToken = 0;
+  c->pToken = NULL;               /* no space allocated, yet. */
+  c->nTokenAllocated = 0;
+
+  *ppCursor = &c->base;
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to
+** simpleOpen() above.
+*/
+static int simpleClose(sqlite3_tokenizer_cursor *pCursor){
+  simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
+  sqlite3_free(c->pToken);
+  sqlite3_free(c);
+  return SQLITE_OK;
+}
+
+/*
+** Extract the next token from a tokenization cursor.  The cursor must
+** have been opened by a prior call to simpleOpen().
+*/
+static int simpleNext(
+  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by simpleOpen */
+  const char **ppToken,               /* OUT: *ppToken is the token text */
+  int *pnBytes,                       /* OUT: Number of bytes in token */
+  int *piStartOffset,                 /* OUT: Starting offset of token */
+  int *piEndOffset,                   /* OUT: Ending offset of token */
+  int *piPosition                     /* OUT: Position integer of token */
+){
+  simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
+  simple_tokenizer *t = (simple_tokenizer *) pCursor->pTokenizer;
+  unsigned char *p = (unsigned char *)c->pInput;
+
+  while( c->iOffset<c->nBytes ){
+    int iStartOffset;
+
+    /* Scan past delimiter characters */
+    while( c->iOffset<c->nBytes && simpleDelim(t, p[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    /* Count non-delimiter characters. */
+    iStartOffset = c->iOffset;
+    while( c->iOffset<c->nBytes && !simpleDelim(t, p[c->iOffset]) ){
+      c->iOffset++;
+    }
+
+    if( c->iOffset>iStartOffset ){
+      int i, n = c->iOffset-iStartOffset;
+      if( n>c->nTokenAllocated ){
+        char *pNew;
+        c->nTokenAllocated = n+20;
+        pNew = sqlite3_realloc64(c->pToken, c->nTokenAllocated);
+        if( !pNew ) return SQLITE_NOMEM;
+        c->pToken = pNew;
+      }
+      for(i=0; i<n; i++){
+        /* TODO(shess) This needs expansion to handle UTF-8
+        ** case-insensitivity.
+        */
+        unsigned char ch = p[iStartOffset+i];
+        c->pToken[i] = (char)((ch>='A' && ch<='Z') ? ch-'A'+'a' : ch);
+      }
+      *ppToken = c->pToken;
+      *pnBytes = n;
+      *piStartOffset = iStartOffset;
+      *piEndOffset = c->iOffset;
+      *piPosition = c->iToken++;
+
+      return SQLITE_OK;
+    }
+  }
+  return SQLITE_DONE;
+}
+
+/*
+** The set of routines that implement the simple tokenizer
+*/
+static const sqlite3_tokenizer_module simpleTokenizerModule = {
+  0,
+  simpleCreate,
+  simpleDestroy,
+  simpleOpen,
+  simpleClose,
+  simpleNext,
+  0,
+};
+
+/*
+** Allocate a new simple tokenizer.  Return a pointer to the new
+** tokenizer in *ppModule
+*/
+SQLITE_PRIVATE void sqlite3Fts3SimpleTokenizerModule(
+  sqlite3_tokenizer_module const**ppModule
+){
+  *ppModule = &simpleTokenizerModule;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_tokenizer1.c *************************************/
+/************** Begin file fts3_tokenize_vtab.c ******************************/
+/*
+** 2013 Apr 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains code for the "fts3tokenize" virtual table module.
+** An fts3tokenize virtual table is created as follows:
+**
+**   CREATE VIRTUAL TABLE <tbl> USING fts3tokenize(
+**       <tokenizer-name>, <arg-1>, ...
+**   );
+**
+** The table created has the following schema:
+**
+**   CREATE TABLE <tbl>(input, token, start, end, position)
+**
+** When queried, the query must include a WHERE clause of type:
+**
+**   input = <string>
+**
+** The virtual table module tokenizes this <string>, using the FTS3
+** tokenizer specified by the arguments to the CREATE VIRTUAL TABLE
+** statement and returns one row for each token in the result. With
+** fields set as follows:
+**
+**   input:   Always set to a copy of <string>
+**   token:   A token from the input.
+**   start:   Byte offset of the token within the input <string>.
+**   end:     Byte offset of the byte immediately following the end of the
+**            token within the input string.
+**   pos:     Token offset of token within input.
+**
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+typedef struct Fts3tokTable Fts3tokTable;
+typedef struct Fts3tokCursor Fts3tokCursor;
+
+/*
+** Virtual table structure.
+*/
+struct Fts3tokTable {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  const sqlite3_tokenizer_module *pMod;
+  sqlite3_tokenizer *pTok;
+};
+
+/*
+** Virtual table cursor structure.
+*/
+struct Fts3tokCursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  char *zInput;                   /* Input string */
+  sqlite3_tokenizer_cursor *pCsr; /* Cursor to iterate through zInput */
+  int iRowid;                     /* Current 'rowid' value */
+  const char *zToken;             /* Current 'token' value */
+  int nToken;                     /* Size of zToken in bytes */
+  int iStart;                     /* Current 'start' value */
+  int iEnd;                       /* Current 'end' value */
+  int iPos;                       /* Current 'pos' value */
+};
+
+/*
+** Query FTS for the tokenizer implementation named zName.
+*/
+static int fts3tokQueryTokenizer(
+  Fts3Hash *pHash,
+  const char *zName,
+  const sqlite3_tokenizer_module **pp,
+  char **pzErr
+){
+  sqlite3_tokenizer_module *p;
+  int nName = (int)strlen(zName);
+
+  p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
+  if( !p ){
+    sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer: %s", zName);
+    return SQLITE_ERROR;
+  }
+
+  *pp = p;
+  return SQLITE_OK;
+}
+
+/*
+** The second argument, argv[], is an array of pointers to nul-terminated
+** strings. This function makes a copy of the array and strings into a
+** single block of memory. It then dequotes any of the strings that appear
+** to be quoted.
+**
+** If successful, output parameter *pazDequote is set to point at the
+** array of dequoted strings and SQLITE_OK is returned. The caller is
+** responsible for eventually calling sqlite3_free() to free the array
+** in this case. Or, if an error occurs, an SQLite error code is returned.
+** The final value of *pazDequote is undefined in this case.
+*/
+static int fts3tokDequoteArray(
+  int argc,                       /* Number of elements in argv[] */
+  const char * const *argv,       /* Input array */
+  char ***pazDequote              /* Output array */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  if( argc==0 ){
+    *pazDequote = 0;
+  }else{
+    int i;
+    int nByte = 0;
+    char **azDequote;
+
+    for(i=0; i<argc; i++){
+      nByte += (int)(strlen(argv[i]) + 1);
+    }
+
+    *pazDequote = azDequote = sqlite3_malloc64(sizeof(char *)*argc + nByte);
+    if( azDequote==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      char *pSpace = (char *)&azDequote[argc];
+      for(i=0; i<argc; i++){
+        int n = (int)strlen(argv[i]);
+        azDequote[i] = pSpace;
+        memcpy(pSpace, argv[i], n+1);
+        sqlite3Fts3Dequote(pSpace);
+        pSpace += (n+1);
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Schema of the tokenizer table.
+*/
+#define FTS3_TOK_SCHEMA "CREATE TABLE x(input, token, start, end, position)"
+
+/*
+** This function does all the work for both the xConnect and xCreate methods.
+** These tables have no persistent representation of their own, so xConnect
+** and xCreate are identical operations.
+**
+**   argv[0]: module name
+**   argv[1]: database name
+**   argv[2]: table name
+**   argv[3]: first argument (tokenizer name)
+*/
+static int fts3tokConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pHash,                    /* Hash table of tokenizers */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  Fts3tokTable *pTab = 0;
+  const sqlite3_tokenizer_module *pMod = 0;
+  sqlite3_tokenizer *pTok = 0;
+  int rc;
+  char **azDequote = 0;
+  int nDequote;
+
+  rc = sqlite3_declare_vtab(db, FTS3_TOK_SCHEMA);
+  if( rc!=SQLITE_OK ) return rc;
+
+  nDequote = argc-3;
+  rc = fts3tokDequoteArray(nDequote, &argv[3], &azDequote);
+
+  if( rc==SQLITE_OK ){
+    const char *zModule;
+    if( nDequote<1 ){
+      zModule = "simple";
+    }else{
+      zModule = azDequote[0];
+    }
+    rc = fts3tokQueryTokenizer((Fts3Hash*)pHash, zModule, &pMod, pzErr);
+  }
+
+  assert( (rc==SQLITE_OK)==(pMod!=0) );
+  if( rc==SQLITE_OK ){
+    const char * const *azArg = 0;
+    if( nDequote>1 ) azArg = (const char * const *)&azDequote[1];
+    rc = pMod->xCreate((nDequote>1 ? nDequote-1 : 0), azArg, &pTok);
+  }
+
+  if( rc==SQLITE_OK ){
+    pTab = (Fts3tokTable *)sqlite3_malloc(sizeof(Fts3tokTable));
+    if( pTab==0 ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    memset(pTab, 0, sizeof(Fts3tokTable));
+    pTab->pMod = pMod;
+    pTab->pTok = pTok;
+    *ppVtab = &pTab->base;
+  }else{
+    if( pTok ){
+      pMod->xDestroy(pTok);
+    }
+  }
+
+  sqlite3_free(azDequote);
+  return rc;
+}
+
+/*
+** This function does the work for both the xDisconnect and xDestroy methods.
+** These tables have no persistent representation of their own, so xDisconnect
+** and xDestroy are identical operations.
+*/
+static int fts3tokDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts3tokTable *pTab = (Fts3tokTable *)pVtab;
+
+  pTab->pMod->xDestroy(pTab->pTok);
+  sqlite3_free(pTab);
+  return SQLITE_OK;
+}
+
+/*
+** xBestIndex - Analyze a WHERE and ORDER BY clause.
+*/
+static int fts3tokBestIndexMethod(
+  sqlite3_vtab *pVTab,
+  sqlite3_index_info *pInfo
+){
+  int i;
+  UNUSED_PARAMETER(pVTab);
+
+  for(i=0; i<pInfo->nConstraint; i++){
+    if( pInfo->aConstraint[i].usable
+     && pInfo->aConstraint[i].iColumn==0
+     && pInfo->aConstraint[i].op==SQLITE_INDEX_CONSTRAINT_EQ
+    ){
+      pInfo->idxNum = 1;
+      pInfo->aConstraintUsage[i].argvIndex = 1;
+      pInfo->aConstraintUsage[i].omit = 1;
+      pInfo->estimatedCost = 1;
+      return SQLITE_OK;
+    }
+  }
+
+  pInfo->idxNum = 0;
+  assert( pInfo->estimatedCost>1000000.0 );
+
+  return SQLITE_OK;
+}
+
+/*
+** xOpen - Open a cursor.
+*/
+static int fts3tokOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  Fts3tokCursor *pCsr;
+  UNUSED_PARAMETER(pVTab);
+
+  pCsr = (Fts3tokCursor *)sqlite3_malloc(sizeof(Fts3tokCursor));
+  if( pCsr==0 ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(Fts3tokCursor));
+
+  *ppCsr = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** Reset the tokenizer cursor passed as the only argument. As if it had
+** just been returned by fts3tokOpenMethod().
+*/
+static void fts3tokResetCursor(Fts3tokCursor *pCsr){
+  if( pCsr->pCsr ){
+    Fts3tokTable *pTab = (Fts3tokTable *)(pCsr->base.pVtab);
+    pTab->pMod->xClose(pCsr->pCsr);
+    pCsr->pCsr = 0;
+  }
+  sqlite3_free(pCsr->zInput);
+  pCsr->zInput = 0;
+  pCsr->zToken = 0;
+  pCsr->nToken = 0;
+  pCsr->iStart = 0;
+  pCsr->iEnd = 0;
+  pCsr->iPos = 0;
+  pCsr->iRowid = 0;
+}
+
+/*
+** xClose - Close a cursor.
+*/
+static int fts3tokCloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+
+  fts3tokResetCursor(pCsr);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** xNext - Advance the cursor to the next row, if any.
+*/
+static int fts3tokNextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+  Fts3tokTable *pTab = (Fts3tokTable *)(pCursor->pVtab);
+  int rc;                         /* Return code */
+
+  pCsr->iRowid++;
+  rc = pTab->pMod->xNext(pCsr->pCsr,
+      &pCsr->zToken, &pCsr->nToken,
+      &pCsr->iStart, &pCsr->iEnd, &pCsr->iPos
+  );
+
+  if( rc!=SQLITE_OK ){
+    fts3tokResetCursor(pCsr);
+    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  }
+
+  return rc;
+}
+
+/*
+** xFilter - Initialize a cursor to point at the start of its data.
+*/
+static int fts3tokFilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  int rc = SQLITE_ERROR;
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+  Fts3tokTable *pTab = (Fts3tokTable *)(pCursor->pVtab);
+  UNUSED_PARAMETER(idxStr);
+  UNUSED_PARAMETER(nVal);
+
+  fts3tokResetCursor(pCsr);
+  if( idxNum==1 ){
+    const char *zByte = (const char *)sqlite3_value_text(apVal[0]);
+    int nByte = sqlite3_value_bytes(apVal[0]);
+    pCsr->zInput = sqlite3_malloc64(nByte+1);
+    if( pCsr->zInput==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      if( nByte>0 ) memcpy(pCsr->zInput, zByte, nByte);
+      pCsr->zInput[nByte] = 0;
+      rc = pTab->pMod->xOpen(pTab->pTok, pCsr->zInput, nByte, &pCsr->pCsr);
+      if( rc==SQLITE_OK ){
+        pCsr->pCsr->pTokenizer = pTab->pTok;
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ) return rc;
+  return fts3tokNextMethod(pCursor);
+}
+
+/*
+** xEof - Return true if the cursor is at EOF, or false otherwise.
+*/
+static int fts3tokEofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+  return (pCsr->zToken==0);
+}
+
+/*
+** xColumn - Return a column value.
+*/
+static int fts3tokColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+
+  /* CREATE TABLE x(input, token, start, end, position) */
+  switch( iCol ){
+    case 0:
+      sqlite3_result_text(pCtx, pCsr->zInput, -1, SQLITE_TRANSIENT);
+      break;
+    case 1:
+      sqlite3_result_text(pCtx, pCsr->zToken, pCsr->nToken, SQLITE_TRANSIENT);
+      break;
+    case 2:
+      sqlite3_result_int(pCtx, pCsr->iStart);
+      break;
+    case 3:
+      sqlite3_result_int(pCtx, pCsr->iEnd);
+      break;
+    default:
+      assert( iCol==4 );
+      sqlite3_result_int(pCtx, pCsr->iPos);
+      break;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** xRowid - Return the current rowid for the cursor.
+*/
+static int fts3tokRowidMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite_int64 *pRowid            /* OUT: Rowid value */
+){
+  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
+  *pRowid = (sqlite3_int64)pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Register the fts3tok module with database connection db. Return SQLITE_OK
+** if successful or an error code if sqlite3_create_module() fails.
+*/
+SQLITE_PRIVATE int sqlite3Fts3InitTok(sqlite3 *db, Fts3Hash *pHash, void(*xDestroy)(void*)){
+  static const sqlite3_module fts3tok_module = {
+     0,                           /* iVersion      */
+     fts3tokConnectMethod,        /* xCreate       */
+     fts3tokConnectMethod,        /* xConnect      */
+     fts3tokBestIndexMethod,      /* xBestIndex    */
+     fts3tokDisconnectMethod,     /* xDisconnect   */
+     fts3tokDisconnectMethod,     /* xDestroy      */
+     fts3tokOpenMethod,           /* xOpen         */
+     fts3tokCloseMethod,          /* xClose        */
+     fts3tokFilterMethod,         /* xFilter       */
+     fts3tokNextMethod,           /* xNext         */
+     fts3tokEofMethod,            /* xEof          */
+     fts3tokColumnMethod,         /* xColumn       */
+     fts3tokRowidMethod,          /* xRowid        */
+     0,                           /* xUpdate       */
+     0,                           /* xBegin        */
+     0,                           /* xSync         */
+     0,                           /* xCommit       */
+     0,                           /* xRollback     */
+     0,                           /* xFindFunction */
+     0,                           /* xRename       */
+     0,                           /* xSavepoint    */
+     0,                           /* xRelease      */
+     0,                           /* xRollbackTo   */
+     0,                           /* xShadowName   */
+     0                            /* xIntegrity    */
+  };
+  int rc;                         /* Return code */
+
+  rc = sqlite3_create_module_v2(
+      db, "fts3tokenize", &fts3tok_module, (void*)pHash, xDestroy
+  );
+  return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_tokenize_vtab.c **********************************/
+/************** Begin file fts3_write.c **************************************/
+/*
+** 2009 Oct 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file is part of the SQLite FTS3 extension module. Specifically,
+** this file contains code to insert, update and delete rows from FTS3
+** tables. It also contains code to merge FTS3 b-tree segments. Some
+** of the sub-routines used to merge segments are also used by the query
+** code in fts3.c.
+*/
+
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+
+#define FTS_MAX_APPENDABLE_HEIGHT 16
+
+/*
+** When full-text index nodes are loaded from disk, the buffer that they
+** are loaded into has the following number of bytes of padding at the end
+** of it. i.e. if a full-text index node is 900 bytes in size, then a buffer
+** of 920 bytes is allocated for it.
+**
+** This means that if we have a pointer into a buffer containing node data,
+** it is always safe to read up to two varints from it without risking an
+** overread, even if the node data is corrupted.
+*/
+#define FTS3_NODE_PADDING (FTS3_VARINT_MAX*2)
+
+/*
+** Under certain circumstances, b-tree nodes (doclists) can be loaded into
+** memory incrementally instead of all at once. This can be a big performance
+** win (reduced IO and CPU) if SQLite stops calling the virtual table xNext()
+** method before retrieving all query results (as may happen, for example,
+** if a query has a LIMIT clause).
+**
+** Incremental loading is used for b-tree nodes FTS3_NODE_CHUNK_THRESHOLD
+** bytes and larger. Nodes are loaded in chunks of FTS3_NODE_CHUNKSIZE bytes.
+** The code is written so that the hard lower-limit for each of these values
+** is 1. Clearly such small values would be inefficient, but can be useful
+** for testing purposes.
+**
+** If this module is built with SQLITE_TEST defined, these constants may
+** be overridden at runtime for testing purposes. File fts3_test.c contains
+** a Tcl interface to read and write the values.
+*/
+#ifdef SQLITE_TEST
+int test_fts3_node_chunksize = (4*1024);
+int test_fts3_node_chunk_threshold = (4*1024)*4;
+# define FTS3_NODE_CHUNKSIZE       test_fts3_node_chunksize
+# define FTS3_NODE_CHUNK_THRESHOLD test_fts3_node_chunk_threshold
+#else
+# define FTS3_NODE_CHUNKSIZE (4*1024)
+# define FTS3_NODE_CHUNK_THRESHOLD (FTS3_NODE_CHUNKSIZE*4)
+#endif
+
+/*
+** The values that may be meaningfully bound to the :1 parameter in
+** statements SQL_REPLACE_STAT and SQL_SELECT_STAT.
+*/
+#define FTS_STAT_DOCTOTAL      0
+#define FTS_STAT_INCRMERGEHINT 1
+#define FTS_STAT_AUTOINCRMERGE 2
+
+/*
+** If FTS_LOG_MERGES is defined, call sqlite3_log() to report each automatic
+** and incremental merge operation that takes place. This is used for
+** debugging FTS only, it should not usually be turned on in production
+** systems.
+*/
+#ifdef FTS3_LOG_MERGES
+static void fts3LogMerge(int nMerge, sqlite3_int64 iAbsLevel){
+  sqlite3_log(SQLITE_OK, "%d-way merge from level %d", nMerge, (int)iAbsLevel);
+}
+#else
+#define fts3LogMerge(x, y)
+#endif
+
+
+typedef struct PendingList PendingList;
+typedef struct SegmentNode SegmentNode;
+typedef struct SegmentWriter SegmentWriter;
+
+/*
+** An instance of the following data structure is used to build doclists
+** incrementally. See function fts3PendingListAppend() for details.
+*/
+struct PendingList {
+  int nData;
+  char *aData;
+  int nSpace;
+  sqlite3_int64 iLastDocid;
+  sqlite3_int64 iLastCol;
+  sqlite3_int64 iLastPos;
+};
+
+
+/*
+** Each cursor has a (possibly empty) linked list of the following objects.
+*/
+struct Fts3DeferredToken {
+  Fts3PhraseToken *pToken;        /* Pointer to corresponding expr token */
+  int iCol;                       /* Column token must occur in */
+  Fts3DeferredToken *pNext;       /* Next in list of deferred tokens */
+  PendingList *pList;             /* Doclist is assembled here */
+};
+
+/*
+** An instance of this structure is used to iterate through the terms on
+** a contiguous set of segment b-tree leaf nodes. Although the details of
+** this structure are only manipulated by code in this file, opaque handles
+** of type Fts3SegReader* are also used by code in fts3.c to iterate through
+** terms when querying the full-text index. See functions:
+**
+**   sqlite3Fts3SegReaderNew()
+**   sqlite3Fts3SegReaderFree()
+**   sqlite3Fts3SegReaderIterate()
+**
+** Methods used to manipulate Fts3SegReader structures:
+**
+**   fts3SegReaderNext()
+**   fts3SegReaderFirstDocid()
+**   fts3SegReaderNextDocid()
+*/
+struct Fts3SegReader {
+  int iIdx;                       /* Index within level, or 0x7FFFFFFF for PT */
+  u8 bLookup;                     /* True for a lookup only */
+  u8 rootOnly;                    /* True for a root-only reader */
+
+  sqlite3_int64 iStartBlock;      /* Rowid of first leaf block to traverse */
+  sqlite3_int64 iLeafEndBlock;    /* Rowid of final leaf block to traverse */
+  sqlite3_int64 iEndBlock;        /* Rowid of final block in segment (or 0) */
+  sqlite3_int64 iCurrentBlock;    /* Current leaf block (or 0) */
+
+  char *aNode;                    /* Pointer to node data (or NULL) */
+  int nNode;                      /* Size of buffer at aNode (or 0) */
+  int nPopulate;                  /* If >0, bytes of buffer aNode[] loaded */
+  sqlite3_blob *pBlob;            /* If not NULL, blob handle to read node */
+
+  Fts3HashElem **ppNextElem;
+
+  /* Variables set by fts3SegReaderNext(). These may be read directly
+  ** by the caller. They are valid from the time SegmentReaderNew() returns
+  ** until SegmentReaderNext() returns something other than SQLITE_OK
+  ** (i.e. SQLITE_DONE).
+  */
+  int nTerm;                      /* Number of bytes in current term */
+  char *zTerm;                    /* Pointer to current term */
+  int nTermAlloc;                 /* Allocated size of zTerm buffer */
+  char *aDoclist;                 /* Pointer to doclist of current entry */
+  int nDoclist;                   /* Size of doclist in current entry */
+
+  /* The following variables are used by fts3SegReaderNextDocid() to iterate
+  ** through the current doclist (aDoclist/nDoclist).
+  */
+  char *pOffsetList;
+  int nOffsetList;                /* For descending pending seg-readers only */
+  sqlite3_int64 iDocid;
+};
+
+#define fts3SegReaderIsPending(p) ((p)->ppNextElem!=0)
+#define fts3SegReaderIsRootOnly(p) ((p)->rootOnly!=0)
+
+/*
+** An instance of this structure is used to create a segment b-tree in the
+** database. The internal details of this type are only accessed by the
+** following functions:
+**
+**   fts3SegWriterAdd()
+**   fts3SegWriterFlush()
+**   fts3SegWriterFree()
+*/
+struct SegmentWriter {
+  SegmentNode *pTree;             /* Pointer to interior tree structure */
+  sqlite3_int64 iFirst;           /* First slot in %_segments written */
+  sqlite3_int64 iFree;            /* Next free slot in %_segments */
+  char *zTerm;                    /* Pointer to previous term buffer */
+  int nTerm;                      /* Number of bytes in zTerm */
+  int nMalloc;                    /* Size of malloc'd buffer at zMalloc */
+  char *zMalloc;                  /* Malloc'd space (possibly) used for zTerm */
+  int nSize;                      /* Size of allocation at aData */
+  int nData;                      /* Bytes of data in aData */
+  char *aData;                    /* Pointer to block from malloc() */
+  i64 nLeafData;                  /* Number of bytes of leaf data written */
+};
+
+/*
+** Type SegmentNode is used by the following three functions to create
+** the interior part of the segment b+-tree structures (everything except
+** the leaf nodes). These functions and type are only ever used by code
+** within the fts3SegWriterXXX() family of functions described above.
+**
+**   fts3NodeAddTerm()
+**   fts3NodeWrite()
+**   fts3NodeFree()
+**
+** When a b+tree is written to the database (either as a result of a merge
+** or the pending-terms table being flushed), leaves are written into the
+** database file as soon as they are completely populated. The interior of
+** the tree is assembled in memory and written out only once all leaves have
+** been populated and stored. This is Ok, as the b+-tree fanout is usually
+** very large, meaning that the interior of the tree consumes relatively
+** little memory.
+*/
+struct SegmentNode {
+  SegmentNode *pParent;           /* Parent node (or NULL for root node) */
+  SegmentNode *pRight;            /* Pointer to right-sibling */
+  SegmentNode *pLeftmost;         /* Pointer to left-most node of this depth */
+  int nEntry;                     /* Number of terms written to node so far */
+  char *zTerm;                    /* Pointer to previous term buffer */
+  int nTerm;                      /* Number of bytes in zTerm */
+  int nMalloc;                    /* Size of malloc'd buffer at zMalloc */
+  char *zMalloc;                  /* Malloc'd space (possibly) used for zTerm */
+  int nData;                      /* Bytes of valid data so far */
+  char *aData;                    /* Node data */
+};
+
+/*
+** Valid values for the second argument to fts3SqlStmt().
+*/
+#define SQL_DELETE_CONTENT             0
+#define SQL_IS_EMPTY                   1
+#define SQL_DELETE_ALL_CONTENT         2
+#define SQL_DELETE_ALL_SEGMENTS        3
+#define SQL_DELETE_ALL_SEGDIR          4
+#define SQL_DELETE_ALL_DOCSIZE         5
+#define SQL_DELETE_ALL_STAT            6
+#define SQL_SELECT_CONTENT_BY_ROWID    7
+#define SQL_NEXT_SEGMENT_INDEX         8
+#define SQL_INSERT_SEGMENTS            9
+#define SQL_NEXT_SEGMENTS_ID          10
+#define SQL_INSERT_SEGDIR             11
+#define SQL_SELECT_LEVEL              12
+#define SQL_SELECT_LEVEL_RANGE        13
+#define SQL_SELECT_LEVEL_COUNT        14
+#define SQL_SELECT_SEGDIR_MAX_LEVEL   15
+#define SQL_DELETE_SEGDIR_LEVEL       16
+#define SQL_DELETE_SEGMENTS_RANGE     17
+#define SQL_CONTENT_INSERT            18
+#define SQL_DELETE_DOCSIZE            19
+#define SQL_REPLACE_DOCSIZE           20
+#define SQL_SELECT_DOCSIZE            21
+#define SQL_SELECT_STAT               22
+#define SQL_REPLACE_STAT              23
+
+#define SQL_SELECT_ALL_PREFIX_LEVEL   24
+#define SQL_DELETE_ALL_TERMS_SEGDIR   25
+#define SQL_DELETE_SEGDIR_RANGE       26
+#define SQL_SELECT_ALL_LANGID         27
+#define SQL_FIND_MERGE_LEVEL          28
+#define SQL_MAX_LEAF_NODE_ESTIMATE    29
+#define SQL_DELETE_SEGDIR_ENTRY       30
+#define SQL_SHIFT_SEGDIR_ENTRY        31
+#define SQL_SELECT_SEGDIR             32
+#define SQL_CHOMP_SEGDIR              33
+#define SQL_SEGMENT_IS_APPENDABLE     34
+#define SQL_SELECT_INDEXES            35
+#define SQL_SELECT_MXLEVEL            36
+
+#define SQL_SELECT_LEVEL_RANGE2       37
+#define SQL_UPDATE_LEVEL_IDX          38
+#define SQL_UPDATE_LEVEL              39
+
+/*
+** This function is used to obtain an SQLite prepared statement handle
+** for the statement identified by the second argument. If successful,
+** *pp is set to the requested statement handle and SQLITE_OK returned.
+** Otherwise, an SQLite error code is returned and *pp is set to 0.
+**
+** If argument apVal is not NULL, then it must point to an array with
+** at least as many entries as the requested statement has bound
+** parameters. The values are bound to the statements parameters before
+** returning.
+*/
+static int fts3SqlStmt(
+  Fts3Table *p,                   /* Virtual table handle */
+  int eStmt,                      /* One of the SQL_XXX constants above */
+  sqlite3_stmt **pp,              /* OUT: Statement handle */
+  sqlite3_value **apVal           /* Values to bind to statement */
+){
+  const char *azSql[] = {
+/* 0  */  "DELETE FROM %Q.'%q_content' WHERE rowid = ?",
+/* 1  */  "SELECT NOT EXISTS(SELECT docid FROM %Q.'%q_content' WHERE rowid!=?)",
+/* 2  */  "DELETE FROM %Q.'%q_content'",
+/* 3  */  "DELETE FROM %Q.'%q_segments'",
+/* 4  */  "DELETE FROM %Q.'%q_segdir'",
+/* 5  */  "DELETE FROM %Q.'%q_docsize'",
+/* 6  */  "DELETE FROM %Q.'%q_stat'",
+/* 7  */  "SELECT %s WHERE rowid=?",
+/* 8  */  "SELECT (SELECT max(idx) FROM %Q.'%q_segdir' WHERE level = ?) + 1",
+/* 9  */  "REPLACE INTO %Q.'%q_segments'(blockid, block) VALUES(?, ?)",
+/* 10 */  "SELECT coalesce((SELECT max(blockid) FROM %Q.'%q_segments') + 1, 1)",
+/* 11 */  "REPLACE INTO %Q.'%q_segdir' VALUES(?,?,?,?,?,?)",
+
+          /* Return segments in order from oldest to newest.*/
+/* 12 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level = ? ORDER BY idx ASC",
+/* 13 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?"
+            "ORDER BY level DESC, idx ASC",
+
+/* 14 */  "SELECT count(*) FROM %Q.'%q_segdir' WHERE level = ?",
+/* 15 */  "SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",
+
+/* 16 */  "DELETE FROM %Q.'%q_segdir' WHERE level = ?",
+/* 17 */  "DELETE FROM %Q.'%q_segments' WHERE blockid BETWEEN ? AND ?",
+/* 18 */  "INSERT INTO %Q.'%q_content' VALUES(%s)",
+/* 19 */  "DELETE FROM %Q.'%q_docsize' WHERE docid = ?",
+/* 20 */  "REPLACE INTO %Q.'%q_docsize' VALUES(?,?)",
+/* 21 */  "SELECT size FROM %Q.'%q_docsize' WHERE docid=?",
+/* 22 */  "SELECT value FROM %Q.'%q_stat' WHERE id=?",
+/* 23 */  "REPLACE INTO %Q.'%q_stat' VALUES(?,?)",
+/* 24 */  "",
+/* 25 */  "",
+
+/* 26 */ "DELETE FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",
+/* 27 */ "SELECT ? UNION SELECT level / (1024 * ?) FROM %Q.'%q_segdir'",
+
+/* This statement is used to determine which level to read the input from
+** when performing an incremental merge. It returns the absolute level number
+** of the oldest level in the db that contains at least ? segments. Or,
+** if no level in the FTS index contains more than ? segments, the statement
+** returns zero rows.  */
+/* 28 */ "SELECT level, count(*) AS cnt FROM %Q.'%q_segdir' "
+         "  GROUP BY level HAVING cnt>=?"
+         "  ORDER BY (level %% 1024) ASC, 2 DESC LIMIT 1",
+
+/* Estimate the upper limit on the number of leaf nodes in a new segment
+** created by merging the oldest :2 segments from absolute level :1. See
+** function sqlite3Fts3Incrmerge() for details.  */
+/* 29 */ "SELECT 2 * total(1 + leaves_end_block - start_block) "
+         "  FROM (SELECT * FROM %Q.'%q_segdir' "
+         "        WHERE level = ? ORDER BY idx ASC LIMIT ?"
+         "  )",
+
+/* SQL_DELETE_SEGDIR_ENTRY
+**   Delete the %_segdir entry on absolute level :1 with index :2.  */
+/* 30 */ "DELETE FROM %Q.'%q_segdir' WHERE level = ? AND idx = ?",
+
+/* SQL_SHIFT_SEGDIR_ENTRY
+**   Modify the idx value for the segment with idx=:3 on absolute level :2
+**   to :1.  */
+/* 31 */ "UPDATE %Q.'%q_segdir' SET idx = ? WHERE level=? AND idx=?",
+
+/* SQL_SELECT_SEGDIR
+**   Read a single entry from the %_segdir table. The entry from absolute
+**   level :1 with index value :2.  */
+/* 32 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
+            "FROM %Q.'%q_segdir' WHERE level = ? AND idx = ?",
+
+/* SQL_CHOMP_SEGDIR
+**   Update the start_block (:1) and root (:2) fields of the %_segdir
+**   entry located on absolute level :3 with index :4.  */
+/* 33 */  "UPDATE %Q.'%q_segdir' SET start_block = ?, root = ?"
+            "WHERE level = ? AND idx = ?",
+
+/* SQL_SEGMENT_IS_APPENDABLE
+**   Return a single row if the segment with end_block=? is appendable. Or
+**   no rows otherwise.  */
+/* 34 */  "SELECT 1 FROM %Q.'%q_segments' WHERE blockid=? AND block IS NULL",
+
+/* SQL_SELECT_INDEXES
+**   Return the list of valid segment indexes for absolute level ?  */
+/* 35 */  "SELECT idx FROM %Q.'%q_segdir' WHERE level=? ORDER BY 1 ASC",
+
+/* SQL_SELECT_MXLEVEL
+**   Return the largest relative level in the FTS index or indexes.  */
+/* 36 */  "SELECT max( level %% 1024 ) FROM %Q.'%q_segdir'",
+
+          /* Return segments in order from oldest to newest.*/
+/* 37 */  "SELECT level, idx, end_block "
+            "FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ? "
+            "ORDER BY level DESC, idx ASC",
+
+          /* Update statements used while promoting segments */
+/* 38 */  "UPDATE OR FAIL %Q.'%q_segdir' SET level=-1,idx=? "
+            "WHERE level=? AND idx=?",
+/* 39 */  "UPDATE OR FAIL %Q.'%q_segdir' SET level=? WHERE level=-1"
+
+  };
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pStmt;
+
+  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
+  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
+
+  pStmt = p->aStmt[eStmt];
+  if( !pStmt ){
+    int f = SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB;
+    char *zSql;
+    if( eStmt==SQL_CONTENT_INSERT ){
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName, p->zWriteExprlist);
+    }else if( eStmt==SQL_SELECT_CONTENT_BY_ROWID ){
+      f &= ~SQLITE_PREPARE_NO_VTAB;
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zReadExprlist);
+    }else{
+      zSql = sqlite3_mprintf(azSql[eStmt], p->zDb, p->zName);
+    }
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v3(p->db, zSql, -1, f, &pStmt, NULL);
+      sqlite3_free(zSql);
+      assert( rc==SQLITE_OK || pStmt==0 );
+      p->aStmt[eStmt] = pStmt;
+    }
+  }
+  if( apVal ){
+    int i;
+    int nParam = sqlite3_bind_parameter_count(pStmt);
+    for(i=0; rc==SQLITE_OK && i<nParam; i++){
+      rc = sqlite3_bind_value(pStmt, i+1, apVal[i]);
+    }
+  }
+  *pp = pStmt;
+  return rc;
+}
+
+
+static int fts3SelectDocsize(
+  Fts3Table *pTab,                /* FTS3 table handle */
+  sqlite3_int64 iDocid,           /* Docid to bind for SQL_SELECT_DOCSIZE */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  sqlite3_stmt *pStmt = 0;        /* Statement requested from fts3SqlStmt() */
+  int rc;                         /* Return code */
+
+  rc = fts3SqlStmt(pTab, SQL_SELECT_DOCSIZE, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iDocid);
+    rc = sqlite3_step(pStmt);
+    if( rc!=SQLITE_ROW || sqlite3_column_type(pStmt, 0)!=SQLITE_BLOB ){
+      rc = sqlite3_reset(pStmt);
+      if( rc==SQLITE_OK ) rc = FTS_CORRUPT_VTAB;
+      pStmt = 0;
+    }else{
+      rc = SQLITE_OK;
+    }
+  }
+
+  *ppStmt = pStmt;
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3SelectDoctotal(
+  Fts3Table *pTab,                /* Fts3 table handle */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  sqlite3_stmt *pStmt = 0;
+  int rc;
+  rc = fts3SqlStmt(pTab, SQL_SELECT_STAT, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
+    if( sqlite3_step(pStmt)!=SQLITE_ROW
+     || sqlite3_column_type(pStmt, 0)!=SQLITE_BLOB
+    ){
+      rc = sqlite3_reset(pStmt);
+      if( rc==SQLITE_OK ) rc = FTS_CORRUPT_VTAB;
+      pStmt = 0;
+    }
+  }
+  *ppStmt = pStmt;
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3SelectDocsize(
+  Fts3Table *pTab,                /* Fts3 table handle */
+  sqlite3_int64 iDocid,           /* Docid to read size data for */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  return fts3SelectDocsize(pTab, iDocid, ppStmt);
+}
+
+/*
+** Similar to fts3SqlStmt(). Except, after binding the parameters in
+** array apVal[] to the SQL statement identified by eStmt, the statement
+** is executed.
+**
+** Returns SQLITE_OK if the statement is successfully executed, or an
+** SQLite error code otherwise.
+*/
+static void fts3SqlExec(
+  int *pRC,                /* Result code */
+  Fts3Table *p,            /* The FTS3 table */
+  int eStmt,               /* Index of statement to evaluate */
+  sqlite3_value **apVal    /* Parameters to bind */
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+  if( *pRC ) return;
+  rc = fts3SqlStmt(p, eStmt, &pStmt, apVal);
+  if( rc==SQLITE_OK ){
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+  }
+  *pRC = rc;
+}
+
+
+/*
+** This function ensures that the caller has obtained an exclusive
+** shared-cache table-lock on the %_segdir table. This is required before
+** writing data to the fts3 table. If this lock is not acquired first, then
+** the caller may end up attempting to take this lock as part of committing
+** a transaction, causing SQLite to return SQLITE_LOCKED or
+** LOCKED_SHAREDCACHEto a COMMIT command.
+**
+** It is best to avoid this because if FTS3 returns any error when
+** committing a transaction, the whole transaction will be rolled back.
+** And this is not what users expect when they get SQLITE_LOCKED_SHAREDCACHE.
+** It can still happen if the user locks the underlying tables directly
+** instead of accessing them via FTS.
+*/
+static int fts3Writelock(Fts3Table *p){
+  int rc = SQLITE_OK;
+
+  if( p->nPendingData==0 ){
+    sqlite3_stmt *pStmt;
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_LEVEL, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_null(pStmt, 1);
+      sqlite3_step(pStmt);
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** FTS maintains a separate indexes for each language-id (a 32-bit integer).
+** Within each language id, a separate index is maintained to store the
+** document terms, and each configured prefix size (configured the FTS
+** "prefix=" option). And each index consists of multiple levels ("relative
+** levels").
+**
+** All three of these values (the language id, the specific index and the
+** level within the index) are encoded in 64-bit integer values stored
+** in the %_segdir table on disk. This function is used to convert three
+** separate component values into the single 64-bit integer value that
+** can be used to query the %_segdir table.
+**
+** Specifically, each language-id/index combination is allocated 1024
+** 64-bit integer level values ("absolute levels"). The main terms index
+** for language-id 0 is allocate values 0-1023. The first prefix index
+** (if any) for language-id 0 is allocated values 1024-2047. And so on.
+** Language 1 indexes are allocated immediately following language 0.
+**
+** So, for a system with nPrefix prefix indexes configured, the block of
+** absolute levels that corresponds to language-id iLangid and index
+** iIndex starts at absolute level ((iLangid * (nPrefix+1) + iIndex) * 1024).
+*/
+static sqlite3_int64 getAbsoluteLevel(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index in p->aIndex[] */
+  int iLevel                      /* Level of segments */
+){
+  sqlite3_int64 iBase;            /* First absolute level for iLangid/iIndex */
+  assert_fts3_nc( iLangid>=0 );
+  assert( p->nIndex>0 );
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  iBase = ((sqlite3_int64)iLangid * p->nIndex + iIndex) * FTS3_SEGDIR_MAXLEVEL;
+  return iBase + iLevel;
+}
+
+/*
+** Set *ppStmt to a statement handle that may be used to iterate through
+** all rows in the %_segdir table, from oldest to newest. If successful,
+** return SQLITE_OK. If an error occurs while preparing the statement,
+** return an SQLite error code.
+**
+** There is only ever one instance of this SQL statement compiled for
+** each FTS3 table.
+**
+** The statement returns the following columns from the %_segdir table:
+**
+**   0: idx
+**   1: start_block
+**   2: leaves_end_block
+**   3: end_block
+**   4: root
+*/
+SQLITE_PRIVATE int sqlite3Fts3AllSegdirs(
+  Fts3Table *p,                   /* FTS3 table */
+  int iLangid,                    /* Language being queried */
+  int iIndex,                     /* Index for p->aIndex[] */
+  int iLevel,                     /* Level to select (relative level) */
+  sqlite3_stmt **ppStmt           /* OUT: Compiled statement */
+){
+  int rc;
+  sqlite3_stmt *pStmt = 0;
+
+  assert( iLevel==FTS3_SEGCURSOR_ALL || iLevel>=0 );
+  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  if( iLevel<0 ){
+    /* "SELECT * FROM %_segdir WHERE level BETWEEN ? AND ? ORDER BY ..." */
+    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_RANGE, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
+      sqlite3_bind_int64(pStmt, 2,
+          getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
+      );
+    }
+  }else{
+    /* "SELECT * FROM %_segdir WHERE level = ? ORDER BY ..." */
+    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex,iLevel));
+    }
+  }
+  *ppStmt = pStmt;
+  return rc;
+}
+
+
+/*
+** Append a single varint to a PendingList buffer. SQLITE_OK is returned
+** if successful, or an SQLite error code otherwise.
+**
+** This function also serves to allocate the PendingList structure itself.
+** For example, to create a new PendingList structure containing two
+** varints:
+**
+**   PendingList *p = 0;
+**   fts3PendingListAppendVarint(&p, 1);
+**   fts3PendingListAppendVarint(&p, 2);
+*/
+static int fts3PendingListAppendVarint(
+  PendingList **pp,               /* IN/OUT: Pointer to PendingList struct */
+  sqlite3_int64 i                 /* Value to append to data */
+){
+  PendingList *p = *pp;
+
+  /* Allocate or grow the PendingList as required. */
+  if( !p ){
+    p = sqlite3_malloc64(sizeof(*p) + 100);
+    if( !p ){
+      return SQLITE_NOMEM;
+    }
+    p->nSpace = 100;
+    p->aData = (char *)&p[1];
+    p->nData = 0;
+  }
+  else if( p->nData+FTS3_VARINT_MAX+1>p->nSpace ){
+    i64 nNew = p->nSpace * 2;
+    p = sqlite3_realloc64(p, sizeof(*p) + nNew);
+    if( !p ){
+      sqlite3_free(*pp);
+      *pp = 0;
+      return SQLITE_NOMEM;
+    }
+    p->nSpace = (int)nNew;
+    p->aData = (char *)&p[1];
+  }
+
+  /* Append the new serialized varint to the end of the list. */
+  p->nData += sqlite3Fts3PutVarint(&p->aData[p->nData], i);
+  p->aData[p->nData] = '\0';
+  *pp = p;
+  return SQLITE_OK;
+}
+
+/*
+** Add a docid/column/position entry to a PendingList structure. Non-zero
+** is returned if the structure is sqlite3_realloced as part of adding
+** the entry. Otherwise, zero.
+**
+** If an OOM error occurs, *pRc is set to SQLITE_NOMEM before returning.
+** Zero is always returned in this case. Otherwise, if no OOM error occurs,
+** it is set to SQLITE_OK.
+*/
+static int fts3PendingListAppend(
+  PendingList **pp,               /* IN/OUT: PendingList structure */
+  sqlite3_int64 iDocid,           /* Docid for entry to add */
+  sqlite3_int64 iCol,             /* Column for entry to add */
+  sqlite3_int64 iPos,             /* Position of term for entry to add */
+  int *pRc                        /* OUT: Return code */
+){
+  PendingList *p = *pp;
+  int rc = SQLITE_OK;
+
+  assert( !p || p->iLastDocid<=iDocid );
+
+  if( !p || p->iLastDocid!=iDocid ){
+    u64 iDelta = (u64)iDocid - (u64)(p ? p->iLastDocid : 0);
+    if( p ){
+      assert( p->nData<p->nSpace );
+      assert( p->aData[p->nData]==0 );
+      p->nData++;
+    }
+    if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iDelta)) ){
+      goto pendinglistappend_out;
+    }
+    p->iLastCol = -1;
+    p->iLastPos = 0;
+    p->iLastDocid = iDocid;
+  }
+  if( iCol>0 && p->iLastCol!=iCol ){
+    if( SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, 1))
+     || SQLITE_OK!=(rc = fts3PendingListAppendVarint(&p, iCol))
+    ){
+      goto pendinglistappend_out;
+    }
+    p->iLastCol = iCol;
+    p->iLastPos = 0;
+  }
+  if( iCol>=0 ){
+    assert( iPos>p->iLastPos || (iPos==0 && p->iLastPos==0) );
+    rc = fts3PendingListAppendVarint(&p, 2+iPos-p->iLastPos);
+    if( rc==SQLITE_OK ){
+      p->iLastPos = iPos;
+    }
+  }
+
+ pendinglistappend_out:
+  *pRc = rc;
+  if( p!=*pp ){
+    *pp = p;
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Free a PendingList object allocated by fts3PendingListAppend().
+*/
+static void fts3PendingListDelete(PendingList *pList){
+  sqlite3_free(pList);
+}
+
+/*
+** Add an entry to one of the pending-terms hash tables.
+*/
+static int fts3PendingTermsAddOne(
+  Fts3Table *p,
+  int iCol,
+  int iPos,
+  Fts3Hash *pHash,                /* Pending terms hash table to add entry to */
+  const char *zToken,
+  int nToken
+){
+  PendingList *pList;
+  int rc = SQLITE_OK;
+
+  pList = (PendingList *)fts3HashFind(pHash, zToken, nToken);
+  if( pList ){
+    p->nPendingData -= (pList->nData + nToken + sizeof(Fts3HashElem));
+  }
+  if( fts3PendingListAppend(&pList, p->iPrevDocid, iCol, iPos, &rc) ){
+    if( pList==fts3HashInsert(pHash, zToken, nToken, pList) ){
+      /* Malloc failed while inserting the new entry. This can only
+      ** happen if there was no previous entry for this token.
+      */
+      assert( 0==fts3HashFind(pHash, zToken, nToken) );
+      sqlite3_free(pList);
+      rc = SQLITE_NOMEM;
+    }
+  }
+  if( rc==SQLITE_OK ){
+    p->nPendingData += (pList->nData + nToken + sizeof(Fts3HashElem));
+  }
+  return rc;
+}
+
+/*
+** Tokenize the nul-terminated string zText and add all tokens to the
+** pending-terms hash-table. The docid used is that currently stored in
+** p->iPrevDocid, and the column is specified by argument iCol.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+*/
+static int fts3PendingTermsAdd(
+  Fts3Table *p,                   /* Table into which text will be inserted */
+  int iLangid,                    /* Language id to use */
+  const char *zText,              /* Text of document to be inserted */
+  int iCol,                       /* Column into which text is being inserted */
+  u32 *pnWord                     /* IN/OUT: Incr. by number tokens inserted */
+){
+  int rc;
+  int iStart = 0;
+  int iEnd = 0;
+  int iPos = 0;
+  int nWord = 0;
+
+  char const *zToken;
+  int nToken = 0;
+
+  sqlite3_tokenizer *pTokenizer = p->pTokenizer;
+  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
+  sqlite3_tokenizer_cursor *pCsr;
+  int (*xNext)(sqlite3_tokenizer_cursor *pCursor,
+      const char**,int*,int*,int*,int*);
+
+  assert( pTokenizer && pModule );
+
+  /* If the user has inserted a NULL value, this function may be called with
+  ** zText==0. In this case, add zero token entries to the hash table and
+  ** return early. */
+  if( zText==0 ){
+    *pnWord = 0;
+    return SQLITE_OK;
+  }
+
+  rc = sqlite3Fts3OpenTokenizer(pTokenizer, iLangid, zText, -1, &pCsr);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  xNext = pModule->xNext;
+  while( SQLITE_OK==rc
+      && SQLITE_OK==(rc = xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos))
+  ){
+    int i;
+    if( iPos>=nWord ) nWord = iPos+1;
+
+    /* Positions cannot be negative; we use -1 as a terminator internally.
+    ** Tokens must have a non-zero length.
+    */
+    if( iPos<0 || !zToken || nToken<=0 ){
+      rc = SQLITE_ERROR;
+      break;
+    }
+
+    /* Add the term to the terms index */
+    rc = fts3PendingTermsAddOne(
+        p, iCol, iPos, &p->aIndex[0].hPending, zToken, nToken
+    );
+
+    /* Add the term to each of the prefix indexes that it is not too
+    ** short for. */
+    for(i=1; rc==SQLITE_OK && i<p->nIndex; i++){
+      struct Fts3Index *pIndex = &p->aIndex[i];
+      if( nToken<pIndex->nPrefix ) continue;
+      rc = fts3PendingTermsAddOne(
+          p, iCol, iPos, &pIndex->hPending, zToken, pIndex->nPrefix
+      );
+    }
+  }
+
+  pModule->xClose(pCsr);
+  *pnWord += nWord;
+  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
+}
+
+/*
+** Calling this function indicates that subsequent calls to
+** fts3PendingTermsAdd() are to add term/position-list pairs for the
+** contents of the document with docid iDocid.
+*/
+static int fts3PendingTermsDocid(
+  Fts3Table *p,                   /* Full-text table handle */
+  int bDelete,                    /* True if this op is a delete */
+  int iLangid,                    /* Language id of row being written */
+  sqlite_int64 iDocid             /* Docid of row being written */
+){
+  assert( iLangid>=0 );
+  assert( bDelete==1 || bDelete==0 );
+
+  /* TODO(shess) Explore whether partially flushing the buffer on
+  ** forced-flush would provide better performance.  I suspect that if
+  ** we ordered the doclists by size and flushed the largest until the
+  ** buffer was half empty, that would let the less frequent terms
+  ** generate longer doclists.
+  */
+  if( iDocid<p->iPrevDocid
+   || (iDocid==p->iPrevDocid && p->bPrevDelete==0)
+   || p->iPrevLangid!=iLangid
+   || p->nPendingData>p->nMaxPendingData
+  ){
+    int rc = sqlite3Fts3PendingTermsFlush(p);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  p->iPrevDocid = iDocid;
+  p->iPrevLangid = iLangid;
+  p->bPrevDelete = bDelete;
+  return SQLITE_OK;
+}
+
+/*
+** Discard the contents of the pending-terms hash tables.
+*/
+SQLITE_PRIVATE void sqlite3Fts3PendingTermsClear(Fts3Table *p){
+  int i;
+  for(i=0; i<p->nIndex; i++){
+    Fts3HashElem *pElem;
+    Fts3Hash *pHash = &p->aIndex[i].hPending;
+    for(pElem=fts3HashFirst(pHash); pElem; pElem=fts3HashNext(pElem)){
+      PendingList *pList = (PendingList *)fts3HashData(pElem);
+      fts3PendingListDelete(pList);
+    }
+    fts3HashClear(pHash);
+  }
+  p->nPendingData = 0;
+}
+
+/*
+** This function is called by the xUpdate() method as part of an INSERT
+** operation. It adds entries for each term in the new record to the
+** pendingTerms hash table.
+**
+** Argument apVal is the same as the similarly named argument passed to
+** fts3InsertData(). Parameter iDocid is the docid of the new row.
+*/
+static int fts3InsertTerms(
+  Fts3Table *p,
+  int iLangid,
+  sqlite3_value **apVal,
+  u32 *aSz
+){
+  int i;                          /* Iterator variable */
+  for(i=2; i<p->nColumn+2; i++){
+    int iCol = i-2;
+    if( p->abNotindexed[iCol]==0 ){
+      const char *zText = (const char *)sqlite3_value_text(apVal[i]);
+      int rc = fts3PendingTermsAdd(p, iLangid, zText, iCol, &aSz[iCol]);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      aSz[p->nColumn] += sqlite3_value_bytes(apVal[i]);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is called by the xUpdate() method for an INSERT operation.
+** The apVal parameter is passed a copy of the apVal argument passed by
+** SQLite to the xUpdate() method. i.e:
+**
+**   apVal[0]                Not used for INSERT.
+**   apVal[1]                rowid
+**   apVal[2]                Left-most user-defined column
+**   ...
+**   apVal[p->nColumn+1]     Right-most user-defined column
+**   apVal[p->nColumn+2]     Hidden column with same name as table
+**   apVal[p->nColumn+3]     Hidden "docid" column (alias for rowid)
+**   apVal[p->nColumn+4]     Hidden languageid column
+*/
+static int fts3InsertData(
+  Fts3Table *p,                   /* Full-text table */
+  sqlite3_value **apVal,          /* Array of values to insert */
+  sqlite3_int64 *piDocid          /* OUT: Docid for row just inserted */
+){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pContentInsert;   /* INSERT INTO %_content VALUES(...) */
+
+  if( p->zContentTbl ){
+    sqlite3_value *pRowid = apVal[p->nColumn+3];
+    if( sqlite3_value_type(pRowid)==SQLITE_NULL ){
+      pRowid = apVal[1];
+    }
+    if( sqlite3_value_type(pRowid)!=SQLITE_INTEGER ){
+      return SQLITE_CONSTRAINT;
+    }
+    *piDocid = sqlite3_value_int64(pRowid);
+    return SQLITE_OK;
+  }
+
+  /* Locate the statement handle used to insert data into the %_content
+  ** table. The SQL for this statement is:
+  **
+  **   INSERT INTO %_content VALUES(?, ?, ?, ...)
+  **
+  ** The statement features N '?' variables, where N is the number of user
+  ** defined columns in the FTS3 table, plus one for the docid field.
+  */
+  rc = fts3SqlStmt(p, SQL_CONTENT_INSERT, &pContentInsert, &apVal[1]);
+  if( rc==SQLITE_OK && p->zLanguageid ){
+    rc = sqlite3_bind_int(
+        pContentInsert, p->nColumn+2,
+        sqlite3_value_int(apVal[p->nColumn+4])
+    );
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* There is a quirk here. The users INSERT statement may have specified
+  ** a value for the "rowid" field, for the "docid" field, or for both.
+  ** Which is a problem, since "rowid" and "docid" are aliases for the
+  ** same value. For example:
+  **
+  **   INSERT INTO fts3tbl(rowid, docid) VALUES(1, 2);
+  **
+  ** In FTS3, this is an error. It is an error to specify non-NULL values
+  ** for both docid and some other rowid alias.
+  */
+  if( SQLITE_NULL!=sqlite3_value_type(apVal[3+p->nColumn]) ){
+    if( SQLITE_NULL==sqlite3_value_type(apVal[0])
+     && SQLITE_NULL!=sqlite3_value_type(apVal[1])
+    ){
+      /* A rowid/docid conflict. */
+      return SQLITE_ERROR;
+    }
+    rc = sqlite3_bind_value(pContentInsert, 1, apVal[3+p->nColumn]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  /* Execute the statement to insert the record. Set *piDocid to the
+  ** new docid value.
+  */
+  sqlite3_step(pContentInsert);
+  rc = sqlite3_reset(pContentInsert);
+
+  *piDocid = sqlite3_last_insert_rowid(p->db);
+  return rc;
+}
+
+
+
+/*
+** Remove all data from the FTS3 table. Clear the hash table containing
+** pending terms.
+*/
+static int fts3DeleteAll(Fts3Table *p, int bContent){
+  int rc = SQLITE_OK;             /* Return code */
+
+  /* Discard the contents of the pending-terms hash table. */
+  sqlite3Fts3PendingTermsClear(p);
+
+  /* Delete everything from the shadow tables. Except, leave %_content as
+  ** is if bContent is false.  */
+  assert( p->zContentTbl==0 || bContent==0 );
+  if( bContent ) fts3SqlExec(&rc, p, SQL_DELETE_ALL_CONTENT, 0);
+  fts3SqlExec(&rc, p, SQL_DELETE_ALL_SEGMENTS, 0);
+  fts3SqlExec(&rc, p, SQL_DELETE_ALL_SEGDIR, 0);
+  if( p->bHasDocsize ){
+    fts3SqlExec(&rc, p, SQL_DELETE_ALL_DOCSIZE, 0);
+  }
+  if( p->bHasStat ){
+    fts3SqlExec(&rc, p, SQL_DELETE_ALL_STAT, 0);
+  }
+  return rc;
+}
+
+/*
+**
+*/
+static int langidFromSelect(Fts3Table *p, sqlite3_stmt *pSelect){
+  int iLangid = 0;
+  if( p->zLanguageid ) iLangid = sqlite3_column_int(pSelect, p->nColumn+1);
+  return iLangid;
+}
+
+/*
+** The first element in the apVal[] array is assumed to contain the docid
+** (an integer) of a row about to be deleted. Remove all terms from the
+** full-text index.
+*/
+static void fts3DeleteTerms(
+  int *pRC,               /* Result code */
+  Fts3Table *p,           /* The FTS table to delete from */
+  sqlite3_value *pRowid,  /* The docid to be deleted */
+  u32 *aSz,               /* Sizes of deleted document written here */
+  int *pbFound            /* OUT: Set to true if row really does exist */
+){
+  int rc;
+  sqlite3_stmt *pSelect;
+
+  assert( *pbFound==0 );
+  if( *pRC ) return;
+  rc = fts3SqlStmt(p, SQL_SELECT_CONTENT_BY_ROWID, &pSelect, &pRowid);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pSelect) ){
+      int i;
+      int iLangid = langidFromSelect(p, pSelect);
+      i64 iDocid = sqlite3_column_int64(pSelect, 0);
+      rc = fts3PendingTermsDocid(p, 1, iLangid, iDocid);
+      for(i=1; rc==SQLITE_OK && i<=p->nColumn; i++){
+        int iCol = i-1;
+        if( p->abNotindexed[iCol]==0 ){
+          const char *zText = (const char *)sqlite3_column_text(pSelect, i);
+          rc = fts3PendingTermsAdd(p, iLangid, zText, -1, &aSz[iCol]);
+          aSz[p->nColumn] += sqlite3_column_bytes(pSelect, i);
+        }
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3_reset(pSelect);
+        *pRC = rc;
+        return;
+      }
+      *pbFound = 1;
+    }
+    rc = sqlite3_reset(pSelect);
+  }else{
+    sqlite3_reset(pSelect);
+  }
+  *pRC = rc;
+}
+
+/*
+** Forward declaration to account for the circular dependency between
+** functions fts3SegmentMerge() and fts3AllocateSegdirIdx().
+*/
+static int fts3SegmentMerge(Fts3Table *, int, int, int);
+
+/*
+** This function allocates a new level iLevel index in the segdir table.
+** Usually, indexes are allocated within a level sequentially starting
+** with 0, so the allocated index is one greater than the value returned
+** by:
+**
+**   SELECT max(idx) FROM %_segdir WHERE level = :iLevel
+**
+** However, if there are already FTS3_MERGE_COUNT indexes at the requested
+** level, they are merged into a single level (iLevel+1) segment and the
+** allocated index is 0.
+**
+** If successful, *piIdx is set to the allocated index slot and SQLITE_OK
+** returned. Otherwise, an SQLite error code is returned.
+*/
+static int fts3AllocateSegdirIdx(
+  Fts3Table *p,
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index for p->aIndex */
+  int iLevel,
+  int *piIdx
+){
+  int rc;                         /* Return Code */
+  sqlite3_stmt *pNextIdx;         /* Query for next idx at level iLevel */
+  int iNext = 0;                  /* Result of query pNextIdx */
+
+  assert( iLangid>=0 );
+  assert( p->nIndex>=1 );
+
+  /* Set variable iNext to the next available segdir index at level iLevel. */
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pNextIdx, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(
+        pNextIdx, 1, getAbsoluteLevel(p, iLangid, iIndex, iLevel)
+    );
+    if( SQLITE_ROW==sqlite3_step(pNextIdx) ){
+      iNext = sqlite3_column_int(pNextIdx, 0);
+    }
+    rc = sqlite3_reset(pNextIdx);
+  }
+
+  if( rc==SQLITE_OK ){
+    /* If iNext is FTS3_MERGE_COUNT, indicating that level iLevel is already
+    ** full, merge all segments in level iLevel into a single iLevel+1
+    ** segment and allocate (newly freed) index 0 at level iLevel. Otherwise,
+    ** if iNext is less than FTS3_MERGE_COUNT, allocate index iNext.
+    */
+    if( iNext>=MergeCount(p) ){
+      fts3LogMerge(16, getAbsoluteLevel(p, iLangid, iIndex, iLevel));
+      rc = fts3SegmentMerge(p, iLangid, iIndex, iLevel);
+      *piIdx = 0;
+    }else{
+      *piIdx = iNext;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The %_segments table is declared as follows:
+**
+**   CREATE TABLE %_segments(blockid INTEGER PRIMARY KEY, block BLOB)
+**
+** This function reads data from a single row of the %_segments table. The
+** specific row is identified by the iBlockid parameter. If paBlob is not
+** NULL, then a buffer is allocated using sqlite3_malloc() and populated
+** with the contents of the blob stored in the "block" column of the
+** identified table row is. Whether or not paBlob is NULL, *pnBlob is set
+** to the size of the blob in bytes before returning.
+**
+** If an error occurs, or the table does not contain the specified row,
+** an SQLite error code is returned. Otherwise, SQLITE_OK is returned. If
+** paBlob is non-NULL, then it is the responsibility of the caller to
+** eventually free the returned buffer.
+**
+** This function may leave an open sqlite3_blob* handle in the
+** Fts3Table.pSegments variable. This handle is reused by subsequent calls
+** to this function. The handle may be closed by calling the
+** sqlite3Fts3SegmentsClose() function. Reusing a blob handle is a handy
+** performance improvement, but the blob handle should always be closed
+** before control is returned to the user (to prevent a lock being held
+** on the database file for longer than necessary). Thus, any virtual table
+** method (xFilter etc.) that may directly or indirectly call this function
+** must call sqlite3Fts3SegmentsClose() before returning.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ReadBlock(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iBlockid,         /* Access the row with blockid=$iBlockid */
+  char **paBlob,                  /* OUT: Blob data in malloc'd buffer */
+  int *pnBlob,                    /* OUT: Size of blob data */
+  int *pnLoad                     /* OUT: Bytes actually loaded */
+){
+  int rc;                         /* Return code */
+
+  /* pnBlob must be non-NULL. paBlob may be NULL or non-NULL. */
+  assert( pnBlob );
+
+  if( p->pSegments ){
+    rc = sqlite3_blob_reopen(p->pSegments, iBlockid);
+  }else{
+    if( 0==p->zSegmentsTbl ){
+      p->zSegmentsTbl = sqlite3_mprintf("%s_segments", p->zName);
+      if( 0==p->zSegmentsTbl ) return SQLITE_NOMEM;
+    }
+    rc = sqlite3_blob_open(
+       p->db, p->zDb, p->zSegmentsTbl, "block", iBlockid, 0, &p->pSegments
+    );
+  }
+
+  if( rc==SQLITE_OK ){
+    int nByte = sqlite3_blob_bytes(p->pSegments);
+    *pnBlob = nByte;
+    if( paBlob ){
+      char *aByte = sqlite3_malloc64((i64)nByte + FTS3_NODE_PADDING);
+      if( !aByte ){
+        rc = SQLITE_NOMEM;
+      }else{
+        if( pnLoad && nByte>(FTS3_NODE_CHUNK_THRESHOLD) ){
+          nByte = FTS3_NODE_CHUNKSIZE;
+          *pnLoad = nByte;
+        }
+        rc = sqlite3_blob_read(p->pSegments, aByte, nByte, 0);
+        memset(&aByte[nByte], 0, FTS3_NODE_PADDING);
+        if( rc!=SQLITE_OK ){
+          sqlite3_free(aByte);
+          aByte = 0;
+        }
+      }
+      *paBlob = aByte;
+    }
+  }else if( rc==SQLITE_ERROR ){
+    rc = FTS_CORRUPT_VTAB;
+  }
+
+  return rc;
+}
+
+/*
+** Close the blob handle at p->pSegments, if it is open. See comments above
+** the sqlite3Fts3ReadBlock() function for details.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SegmentsClose(Fts3Table *p){
+  sqlite3_blob_close(p->pSegments);
+  p->pSegments = 0;
+}
+
+static int fts3SegReaderIncrRead(Fts3SegReader *pReader){
+  int nRead;                      /* Number of bytes to read */
+  int rc;                         /* Return code */
+
+  nRead = MIN(pReader->nNode - pReader->nPopulate, FTS3_NODE_CHUNKSIZE);
+  rc = sqlite3_blob_read(
+      pReader->pBlob,
+      &pReader->aNode[pReader->nPopulate],
+      nRead,
+      pReader->nPopulate
+  );
+
+  if( rc==SQLITE_OK ){
+    pReader->nPopulate += nRead;
+    memset(&pReader->aNode[pReader->nPopulate], 0, FTS3_NODE_PADDING);
+    if( pReader->nPopulate==pReader->nNode ){
+      sqlite3_blob_close(pReader->pBlob);
+      pReader->pBlob = 0;
+      pReader->nPopulate = 0;
+    }
+  }
+  return rc;
+}
+
+static int fts3SegReaderRequire(Fts3SegReader *pReader, char *pFrom, int nByte){
+  int rc = SQLITE_OK;
+  assert( !pReader->pBlob
+       || (pFrom>=pReader->aNode && pFrom<&pReader->aNode[pReader->nNode])
+  );
+  while( pReader->pBlob && rc==SQLITE_OK
+     &&  (pFrom - pReader->aNode + nByte)>pReader->nPopulate
+  ){
+    rc = fts3SegReaderIncrRead(pReader);
+  }
+  return rc;
+}
+
+/*
+** Set an Fts3SegReader cursor to point at EOF.
+*/
+static void fts3SegReaderSetEof(Fts3SegReader *pSeg){
+  if( !fts3SegReaderIsRootOnly(pSeg) ){
+    sqlite3_free(pSeg->aNode);
+    sqlite3_blob_close(pSeg->pBlob);
+    pSeg->pBlob = 0;
+  }
+  pSeg->aNode = 0;
+}
+
+/*
+** Move the iterator passed as the first argument to the next term in the
+** segment. If successful, SQLITE_OK is returned. If there is no next term,
+** SQLITE_DONE. Otherwise, an SQLite error code.
+*/
+static int fts3SegReaderNext(
+  Fts3Table *p,
+  Fts3SegReader *pReader,
+  int bIncr
+){
+  int rc;                         /* Return code of various sub-routines */
+  char *pNext;                    /* Cursor variable */
+  int nPrefix;                    /* Number of bytes in term prefix */
+  int nSuffix;                    /* Number of bytes in term suffix */
+
+  if( !pReader->aDoclist ){
+    pNext = pReader->aNode;
+  }else{
+    pNext = &pReader->aDoclist[pReader->nDoclist];
+  }
+
+  if( !pNext || pNext>=&pReader->aNode[pReader->nNode] ){
+
+    if( fts3SegReaderIsPending(pReader) ){
+      Fts3HashElem *pElem = *(pReader->ppNextElem);
+      sqlite3_free(pReader->aNode);
+      pReader->aNode = 0;
+      if( pElem ){
+        char *aCopy;
+        PendingList *pList = (PendingList *)fts3HashData(pElem);
+        int nCopy = pList->nData+1;
+
+        int nTerm = fts3HashKeysize(pElem);
+        if( (nTerm+1)>pReader->nTermAlloc ){
+          sqlite3_free(pReader->zTerm);
+          pReader->zTerm = (char*)sqlite3_malloc64(((i64)nTerm+1)*2);
+          if( !pReader->zTerm ) return SQLITE_NOMEM;
+          pReader->nTermAlloc = (nTerm+1)*2;
+        }
+        memcpy(pReader->zTerm, fts3HashKey(pElem), nTerm);
+        pReader->zTerm[nTerm] = '\0';
+        pReader->nTerm = nTerm;
+
+        aCopy = (char*)sqlite3_malloc64(nCopy);
+        if( !aCopy ) return SQLITE_NOMEM;
+        memcpy(aCopy, pList->aData, nCopy);
+        pReader->nNode = pReader->nDoclist = nCopy;
+        pReader->aNode = pReader->aDoclist = aCopy;
+        pReader->ppNextElem++;
+        assert( pReader->aNode );
+      }
+      return SQLITE_OK;
+    }
+
+    fts3SegReaderSetEof(pReader);
+
+    /* If iCurrentBlock>=iLeafEndBlock, this is an EOF condition. All leaf
+    ** blocks have already been traversed.  */
+#ifdef CORRUPT_DB
+    assert( pReader->iCurrentBlock<=pReader->iLeafEndBlock || CORRUPT_DB );
+#endif
+    if( pReader->iCurrentBlock>=pReader->iLeafEndBlock ){
+      return SQLITE_OK;
+    }
+
+    rc = sqlite3Fts3ReadBlock(
+        p, ++pReader->iCurrentBlock, &pReader->aNode, &pReader->nNode,
+        (bIncr ? &pReader->nPopulate : 0)
+    );
+    if( rc!=SQLITE_OK ) return rc;
+    assert( pReader->pBlob==0 );
+    if( bIncr && pReader->nPopulate<pReader->nNode ){
+      pReader->pBlob = p->pSegments;
+      p->pSegments = 0;
+    }
+    pNext = pReader->aNode;
+  }
+
+  assert( !fts3SegReaderIsPending(pReader) );
+
+  rc = fts3SegReaderRequire(pReader, pNext, FTS3_VARINT_MAX*2);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Because of the FTS3_NODE_PADDING bytes of padding, the following is
+  ** safe (no risk of overread) even if the node data is corrupted. */
+  pNext += fts3GetVarint32(pNext, &nPrefix);
+  pNext += fts3GetVarint32(pNext, &nSuffix);
+  if( nSuffix<=0
+   || (&pReader->aNode[pReader->nNode] - pNext)<nSuffix
+   || nPrefix>pReader->nTerm
+  ){
+    return FTS_CORRUPT_VTAB;
+  }
+
+  /* Both nPrefix and nSuffix were read by fts3GetVarint32() and so are
+  ** between 0 and 0x7FFFFFFF. But the sum of the two may cause integer
+  ** overflow - hence the (i64) casts.  */
+  if( (i64)nPrefix+nSuffix>(i64)pReader->nTermAlloc ){
+    i64 nNew = ((i64)nPrefix+nSuffix)*2;
+    char *zNew = sqlite3_realloc64(pReader->zTerm, nNew);
+    if( !zNew ){
+      return SQLITE_NOMEM;
+    }
+    pReader->zTerm = zNew;
+    pReader->nTermAlloc = nNew;
+  }
+
+  rc = fts3SegReaderRequire(pReader, pNext, nSuffix+FTS3_VARINT_MAX);
+  if( rc!=SQLITE_OK ) return rc;
+
+  memcpy(&pReader->zTerm[nPrefix], pNext, nSuffix);
+  pReader->nTerm = nPrefix+nSuffix;
+  pNext += nSuffix;
+  pNext += fts3GetVarint32(pNext, &pReader->nDoclist);
+  pReader->aDoclist = pNext;
+  pReader->pOffsetList = 0;
+
+  /* Check that the doclist does not appear to extend past the end of the
+  ** b-tree node. And that the final byte of the doclist is 0x00. If either
+  ** of these statements is untrue, then the data structure is corrupt.
+  */
+  if( pReader->nDoclist > pReader->nNode-(pReader->aDoclist-pReader->aNode)
+   || (pReader->nPopulate==0 && pReader->aDoclist[pReader->nDoclist-1])
+   || pReader->nDoclist==0
+  ){
+    return FTS_CORRUPT_VTAB;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Set the SegReader to point to the first docid in the doclist associated
+** with the current term.
+*/
+static int fts3SegReaderFirstDocid(Fts3Table *pTab, Fts3SegReader *pReader){
+  int rc = SQLITE_OK;
+  assert( pReader->aDoclist );
+  assert( !pReader->pOffsetList );
+  if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
+    u8 bEof = 0;
+    pReader->iDocid = 0;
+    pReader->nOffsetList = 0;
+    sqlite3Fts3DoclistPrev(0,
+        pReader->aDoclist, pReader->nDoclist, &pReader->pOffsetList,
+        &pReader->iDocid, &pReader->nOffsetList, &bEof
+    );
+  }else{
+    rc = fts3SegReaderRequire(pReader, pReader->aDoclist, FTS3_VARINT_MAX);
+    if( rc==SQLITE_OK ){
+      int n = sqlite3Fts3GetVarint(pReader->aDoclist, &pReader->iDocid);
+      pReader->pOffsetList = &pReader->aDoclist[n];
+    }
+  }
+  return rc;
+}
+
+/*
+** Advance the SegReader to point to the next docid in the doclist
+** associated with the current term.
+**
+** If arguments ppOffsetList and pnOffsetList are not NULL, then
+** *ppOffsetList is set to point to the first column-offset list
+** in the doclist entry (i.e. immediately past the docid varint).
+** *pnOffsetList is set to the length of the set of column-offset
+** lists, not including the nul-terminator byte. For example:
+*/
+static int fts3SegReaderNextDocid(
+  Fts3Table *pTab,
+  Fts3SegReader *pReader,         /* Reader to advance to next docid */
+  char **ppOffsetList,            /* OUT: Pointer to current position-list */
+  int *pnOffsetList               /* OUT: Length of *ppOffsetList in bytes */
+){
+  int rc = SQLITE_OK;
+  char *p = pReader->pOffsetList;
+  char c = 0;
+
+  assert( p );
+
+  if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
+    /* A pending-terms seg-reader for an FTS4 table that uses order=desc.
+    ** Pending-terms doclists are always built up in ascending order, so
+    ** we have to iterate through them backwards here. */
+    u8 bEof = 0;
+    if( ppOffsetList ){
+      *ppOffsetList = pReader->pOffsetList;
+      *pnOffsetList = pReader->nOffsetList - 1;
+    }
+    sqlite3Fts3DoclistPrev(0,
+        pReader->aDoclist, pReader->nDoclist, &p, &pReader->iDocid,
+        &pReader->nOffsetList, &bEof
+    );
+    if( bEof ){
+      pReader->pOffsetList = 0;
+    }else{
+      pReader->pOffsetList = p;
+    }
+  }else{
+    char *pEnd = &pReader->aDoclist[pReader->nDoclist];
+
+    /* Pointer p currently points at the first byte of an offset list. The
+    ** following block advances it to point one byte past the end of
+    ** the same offset list. */
+    while( 1 ){
+
+      /* The following line of code (and the "p++" below the while() loop) is
+      ** normally all that is required to move pointer p to the desired
+      ** position. The exception is if this node is being loaded from disk
+      ** incrementally and pointer "p" now points to the first byte past
+      ** the populated part of pReader->aNode[].
+      */
+      while( *p | c ) c = *p++ & 0x80;
+      assert( *p==0 );
+
+      if( pReader->pBlob==0 || p<&pReader->aNode[pReader->nPopulate] ) break;
+      rc = fts3SegReaderIncrRead(pReader);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    p++;
+
+    /* If required, populate the output variables with a pointer to and the
+    ** size of the previous offset-list.
+    */
+    if( ppOffsetList ){
+      *ppOffsetList = pReader->pOffsetList;
+      *pnOffsetList = (int)(p - pReader->pOffsetList - 1);
+    }
+
+    /* List may have been edited in place by fts3EvalNearTrim() */
+    while( p<pEnd && *p==0 ) p++;
+
+    /* If there are no more entries in the doclist, set pOffsetList to
+    ** NULL. Otherwise, set Fts3SegReader.iDocid to the next docid and
+    ** Fts3SegReader.pOffsetList to point to the next offset list before
+    ** returning.
+    */
+    if( p>=pEnd ){
+      pReader->pOffsetList = 0;
+    }else{
+      rc = fts3SegReaderRequire(pReader, p, FTS3_VARINT_MAX);
+      if( rc==SQLITE_OK ){
+        u64 iDelta;
+        pReader->pOffsetList = p + sqlite3Fts3GetVarintU(p, &iDelta);
+        if( pTab->bDescIdx ){
+          pReader->iDocid = (i64)((u64)pReader->iDocid - iDelta);
+        }else{
+          pReader->iDocid = (i64)((u64)pReader->iDocid + iDelta);
+        }
+      }
+    }
+  }
+
+  return rc;
+}
+
+
+SQLITE_PRIVATE int sqlite3Fts3MsrOvfl(
+  Fts3Cursor *pCsr,
+  Fts3MultiSegReader *pMsr,
+  int *pnOvfl
+){
+  Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
+  int nOvfl = 0;
+  int ii;
+  int rc = SQLITE_OK;
+  int pgsz = p->nPgsz;
+
+  assert( p->bFts4 );
+  assert( pgsz>0 );
+
+  for(ii=0; rc==SQLITE_OK && ii<pMsr->nSegment; ii++){
+    Fts3SegReader *pReader = pMsr->apSegment[ii];
+    if( !fts3SegReaderIsPending(pReader)
+     && !fts3SegReaderIsRootOnly(pReader)
+    ){
+      sqlite3_int64 jj;
+      for(jj=pReader->iStartBlock; jj<=pReader->iLeafEndBlock; jj++){
+        int nBlob;
+        rc = sqlite3Fts3ReadBlock(p, jj, 0, &nBlob, 0);
+        if( rc!=SQLITE_OK ) break;
+        if( (nBlob+35)>pgsz ){
+          nOvfl += (nBlob + 34)/pgsz;
+        }
+      }
+    }
+  }
+  *pnOvfl = nOvfl;
+  return rc;
+}
+
+/*
+** Free all allocations associated with the iterator passed as the
+** second argument.
+*/
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFree(Fts3SegReader *pReader){
+  if( pReader ){
+    sqlite3_free(pReader->zTerm);
+    if( !fts3SegReaderIsRootOnly(pReader) ){
+      sqlite3_free(pReader->aNode);
+    }
+    sqlite3_blob_close(pReader->pBlob);
+  }
+  sqlite3_free(pReader);
+}
+
+/*
+** Allocate a new SegReader object.
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderNew(
+  int iAge,                       /* Segment "age". */
+  int bLookup,                    /* True for a lookup only */
+  sqlite3_int64 iStartLeaf,       /* First leaf to traverse */
+  sqlite3_int64 iEndLeaf,         /* Final leaf to traverse */
+  sqlite3_int64 iEndBlock,        /* Final block of segment */
+  const char *zRoot,              /* Buffer containing root node */
+  int nRoot,                      /* Size of buffer containing root node */
+  Fts3SegReader **ppReader        /* OUT: Allocated Fts3SegReader */
+){
+  Fts3SegReader *pReader;         /* Newly allocated SegReader object */
+  int nExtra = 0;                 /* Bytes to allocate segment root node */
+
+  assert( zRoot!=0 || nRoot==0 );
+#ifdef CORRUPT_DB
+  assert( zRoot!=0 || CORRUPT_DB );
+#endif
+
+  if( iStartLeaf==0 ){
+    if( iEndLeaf!=0 ) return FTS_CORRUPT_VTAB;
+    nExtra = nRoot + FTS3_NODE_PADDING;
+  }
+
+  pReader = (Fts3SegReader *)sqlite3_malloc64(sizeof(Fts3SegReader) + nExtra);
+  if( !pReader ){
+    return SQLITE_NOMEM;
+  }
+  memset(pReader, 0, sizeof(Fts3SegReader));
+  pReader->iIdx = iAge;
+  pReader->bLookup = bLookup!=0;
+  pReader->iStartBlock = iStartLeaf;
+  pReader->iLeafEndBlock = iEndLeaf;
+  pReader->iEndBlock = iEndBlock;
+
+  if( nExtra ){
+    /* The entire segment is stored in the root node. */
+    pReader->aNode = (char *)&pReader[1];
+    pReader->rootOnly = 1;
+    pReader->nNode = nRoot;
+    if( nRoot ) memcpy(pReader->aNode, zRoot, nRoot);
+    memset(&pReader->aNode[nRoot], 0, FTS3_NODE_PADDING);
+  }else{
+    pReader->iCurrentBlock = iStartLeaf-1;
+  }
+  *ppReader = pReader;
+  return SQLITE_OK;
+}
+
+/*
+** This is a comparison function used as a qsort() callback when sorting
+** an array of pending terms by term. This occurs as part of flushing
+** the contents of the pending-terms hash table to the database.
+*/
+static int SQLITE_CDECL fts3CompareElemByTerm(
+  const void *lhs,
+  const void *rhs
+){
+  char *z1 = fts3HashKey(*(Fts3HashElem **)lhs);
+  char *z2 = fts3HashKey(*(Fts3HashElem **)rhs);
+  int n1 = fts3HashKeysize(*(Fts3HashElem **)lhs);
+  int n2 = fts3HashKeysize(*(Fts3HashElem **)rhs);
+
+  int n = (n1<n2 ? n1 : n2);
+  int c = memcmp(z1, z2, n);
+  if( c==0 ){
+    c = n1 - n2;
+  }
+  return c;
+}
+
+/*
+** This function is used to allocate an Fts3SegReader that iterates through
+** a subset of the terms stored in the Fts3Table.pendingTerms array.
+**
+** If the isPrefixIter parameter is zero, then the returned SegReader iterates
+** through each term in the pending-terms table. Or, if isPrefixIter is
+** non-zero, it iterates through each term and its prefixes. For example, if
+** the pending terms hash table contains the terms "sqlite", "mysql" and
+** "firebird", then the iterator visits the following 'terms' (in the order
+** shown):
+**
+**   f fi fir fire fireb firebi firebir firebird
+**   m my mys mysq mysql
+**   s sq sql sqli sqlit sqlite
+**
+** Whereas if isPrefixIter is zero, the terms visited are:
+**
+**   firebird mysql sqlite
+*/
+SQLITE_PRIVATE int sqlite3Fts3SegReaderPending(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iIndex,                     /* Index for p->aIndex */
+  const char *zTerm,              /* Term to search for */
+  int nTerm,                      /* Size of buffer zTerm */
+  int bPrefix,                    /* True for a prefix iterator */
+  Fts3SegReader **ppReader        /* OUT: SegReader for pending-terms */
+){
+  Fts3SegReader *pReader = 0;     /* Fts3SegReader object to return */
+  Fts3HashElem *pE;               /* Iterator variable */
+  Fts3HashElem **aElem = 0;       /* Array of term hash entries to scan */
+  int nElem = 0;                  /* Size of array at aElem */
+  int rc = SQLITE_OK;             /* Return Code */
+  Fts3Hash *pHash;
+
+  pHash = &p->aIndex[iIndex].hPending;
+  if( bPrefix ){
+    int nAlloc = 0;               /* Size of allocated array at aElem */
+
+    for(pE=fts3HashFirst(pHash); pE; pE=fts3HashNext(pE)){
+      char *zKey = (char *)fts3HashKey(pE);
+      int nKey = fts3HashKeysize(pE);
+      if( nTerm==0 || (nKey>=nTerm && 0==memcmp(zKey, zTerm, nTerm)) ){
+        if( nElem==nAlloc ){
+          Fts3HashElem **aElem2;
+          nAlloc += 16;
+          aElem2 = (Fts3HashElem **)sqlite3_realloc64(
+              aElem, nAlloc*sizeof(Fts3HashElem *)
+          );
+          if( !aElem2 ){
+            rc = SQLITE_NOMEM;
+            nElem = 0;
+            break;
+          }
+          aElem = aElem2;
+        }
+
+        aElem[nElem++] = pE;
+      }
+    }
+
+    /* If more than one term matches the prefix, sort the Fts3HashElem
+    ** objects in term order using qsort(). This uses the same comparison
+    ** callback as is used when flushing terms to disk.
+    */
+    if( nElem>1 ){
+      qsort(aElem, nElem, sizeof(Fts3HashElem *), fts3CompareElemByTerm);
+    }
+
+  }else{
+    /* The query is a simple term lookup that matches at most one term in
+    ** the index. All that is required is a straight hash-lookup.
+    **
+    ** Because the stack address of pE may be accessed via the aElem pointer
+    ** below, the "Fts3HashElem *pE" must be declared so that it is valid
+    ** within this entire function, not just this "else{...}" block.
+    */
+    pE = fts3HashFindElem(pHash, zTerm, nTerm);
+    if( pE ){
+      aElem = &pE;
+      nElem = 1;
+    }
+  }
+
+  if( nElem>0 ){
+    sqlite3_int64 nByte;
+    nByte = sizeof(Fts3SegReader) + (nElem+1)*sizeof(Fts3HashElem *);
+    pReader = (Fts3SegReader *)sqlite3_malloc64(nByte);
+    if( !pReader ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pReader, 0, nByte);
+      pReader->iIdx = 0x7FFFFFFF;
+      pReader->ppNextElem = (Fts3HashElem **)&pReader[1];
+      memcpy(pReader->ppNextElem, aElem, nElem*sizeof(Fts3HashElem *));
+    }
+  }
+
+  if( bPrefix ){
+    sqlite3_free(aElem);
+  }
+  *ppReader = pReader;
+  return rc;
+}
+
+/*
+** Compare the entries pointed to by two Fts3SegReader structures.
+** Comparison is as follows:
+**
+**   1) EOF is greater than not EOF.
+**
+**   2) The current terms (if any) are compared using memcmp(). If one
+**      term is a prefix of another, the longer term is considered the
+**      larger.
+**
+**   3) By segment age. An older segment is considered larger.
+*/
+static int fts3SegReaderCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc;
+  if( pLhs->aNode && pRhs->aNode ){
+    int rc2 = pLhs->nTerm - pRhs->nTerm;
+    if( rc2<0 ){
+      rc = memcmp(pLhs->zTerm, pRhs->zTerm, pLhs->nTerm);
+    }else{
+      rc = memcmp(pLhs->zTerm, pRhs->zTerm, pRhs->nTerm);
+    }
+    if( rc==0 ){
+      rc = rc2;
+    }
+  }else{
+    rc = (pLhs->aNode==0) - (pRhs->aNode==0);
+  }
+  if( rc==0 ){
+    rc = pRhs->iIdx - pLhs->iIdx;
+  }
+  assert_fts3_nc( rc!=0 );
+  return rc;
+}
+
+/*
+** A different comparison function for SegReader structures. In this
+** version, it is assumed that each SegReader points to an entry in
+** a doclist for identical terms. Comparison is made as follows:
+**
+**   1) EOF (end of doclist in this case) is greater than not EOF.
+**
+**   2) By current docid.
+**
+**   3) By segment age. An older segment is considered larger.
+*/
+static int fts3SegReaderDoclistCmp(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
+  if( rc==0 ){
+    if( pLhs->iDocid==pRhs->iDocid ){
+      rc = pRhs->iIdx - pLhs->iIdx;
+    }else{
+      rc = (pLhs->iDocid > pRhs->iDocid) ? 1 : -1;
+    }
+  }
+  assert( pLhs->aNode && pRhs->aNode );
+  return rc;
+}
+static int fts3SegReaderDoclistCmpRev(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
+  int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
+  if( rc==0 ){
+    if( pLhs->iDocid==pRhs->iDocid ){
+      rc = pRhs->iIdx - pLhs->iIdx;
+    }else{
+      rc = (pLhs->iDocid < pRhs->iDocid) ? 1 : -1;
+    }
+  }
+  assert( pLhs->aNode && pRhs->aNode );
+  return rc;
+}
+
+/*
+** Compare the term that the Fts3SegReader object passed as the first argument
+** points to with the term specified by arguments zTerm and nTerm.
+**
+** If the pSeg iterator is already at EOF, return 0. Otherwise, return
+** -ve if the pSeg term is less than zTerm/nTerm, 0 if the two terms are
+** equal, or +ve if the pSeg term is greater than zTerm/nTerm.
+*/
+static int fts3SegReaderTermCmp(
+  Fts3SegReader *pSeg,            /* Segment reader object */
+  const char *zTerm,              /* Term to compare to */
+  int nTerm                       /* Size of term zTerm in bytes */
+){
+  int res = 0;
+  if( pSeg->aNode ){
+    if( pSeg->nTerm>nTerm ){
+      res = memcmp(pSeg->zTerm, zTerm, nTerm);
+    }else{
+      res = memcmp(pSeg->zTerm, zTerm, pSeg->nTerm);
+    }
+    if( res==0 ){
+      res = pSeg->nTerm-nTerm;
+    }
+  }
+  return res;
+}
+
+/*
+** Argument apSegment is an array of nSegment elements. It is known that
+** the final (nSegment-nSuspect) members are already in sorted order
+** (according to the comparison function provided). This function shuffles
+** the array around until all entries are in sorted order.
+*/
+static void fts3SegReaderSort(
+  Fts3SegReader **apSegment,                     /* Array to sort entries of */
+  int nSegment,                                  /* Size of apSegment array */
+  int nSuspect,                                  /* Unsorted entry count */
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *)  /* Comparison function */
+){
+  int i;                          /* Iterator variable */
+
+  assert( nSuspect<=nSegment );
+
+  if( nSuspect==nSegment ) nSuspect--;
+  for(i=nSuspect-1; i>=0; i--){
+    int j;
+    for(j=i; j<(nSegment-1); j++){
+      Fts3SegReader *pTmp;
+      if( xCmp(apSegment[j], apSegment[j+1])<0 ) break;
+      pTmp = apSegment[j+1];
+      apSegment[j+1] = apSegment[j];
+      apSegment[j] = pTmp;
+    }
+  }
+
+#ifndef NDEBUG
+  /* Check that the list really is sorted now. */
+  for(i=0; i<(nSuspect-1); i++){
+    assert( xCmp(apSegment[i], apSegment[i+1])<0 );
+  }
+#endif
+}
+
+/*
+** Insert a record into the %_segments table.
+*/
+static int fts3WriteSegment(
+  Fts3Table *p,                   /* Virtual table handle */
+  sqlite3_int64 iBlock,           /* Block id for new block */
+  char *z,                        /* Pointer to buffer containing block data */
+  int n                           /* Size of buffer z in bytes */
+){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_INSERT_SEGMENTS, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iBlock);
+    sqlite3_bind_blob(pStmt, 2, z, n, SQLITE_STATIC);
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+    sqlite3_bind_null(pStmt, 2);
+  }
+  return rc;
+}
+
+/*
+** Find the largest relative level number in the table. If successful, set
+** *pnMax to this value and return SQLITE_OK. Otherwise, if an error occurs,
+** set *pnMax to zero and return an SQLite error code.
+*/
+SQLITE_PRIVATE int sqlite3Fts3MaxLevel(Fts3Table *p, int *pnMax){
+  int rc;
+  int mxLevel = 0;
+  sqlite3_stmt *pStmt = 0;
+
+  rc = fts3SqlStmt(p, SQL_SELECT_MXLEVEL, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      mxLevel = sqlite3_column_int(pStmt, 0);
+    }
+    rc = sqlite3_reset(pStmt);
+  }
+  *pnMax = mxLevel;
+  return rc;
+}
+
+/*
+** Insert a record into the %_segdir table.
+*/
+static int fts3WriteSegdir(
+  Fts3Table *p,                   /* Virtual table handle */
+  sqlite3_int64 iLevel,           /* Value for "level" field (absolute level) */
+  int iIdx,                       /* Value for "idx" field */
+  sqlite3_int64 iStartBlock,      /* Value for "start_block" field */
+  sqlite3_int64 iLeafEndBlock,    /* Value for "leaves_end_block" field */
+  sqlite3_int64 iEndBlock,        /* Value for "end_block" field */
+  sqlite3_int64 nLeafData,        /* Bytes of leaf data in segment */
+  char *zRoot,                    /* Blob value for "root" field */
+  int nRoot                       /* Number of bytes in buffer zRoot */
+){
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_INSERT_SEGDIR, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pStmt, 1, iLevel);
+    sqlite3_bind_int(pStmt, 2, iIdx);
+    sqlite3_bind_int64(pStmt, 3, iStartBlock);
+    sqlite3_bind_int64(pStmt, 4, iLeafEndBlock);
+    if( nLeafData==0 ){
+      sqlite3_bind_int64(pStmt, 5, iEndBlock);
+    }else{
+      char *zEnd = sqlite3_mprintf("%lld %lld", iEndBlock, nLeafData);
+      if( !zEnd ) return SQLITE_NOMEM;
+      sqlite3_bind_text(pStmt, 5, zEnd, -1, sqlite3_free);
+    }
+    sqlite3_bind_blob(pStmt, 6, zRoot, nRoot, SQLITE_STATIC);
+    sqlite3_step(pStmt);
+    rc = sqlite3_reset(pStmt);
+    sqlite3_bind_null(pStmt, 6);
+  }
+  return rc;
+}
+
+/*
+** Return the size of the common prefix (if any) shared by zPrev and
+** zNext, in bytes. For example,
+**
+**   fts3PrefixCompress("abc", 3, "abcdef", 6)   // returns 3
+**   fts3PrefixCompress("abX", 3, "abcdef", 6)   // returns 2
+**   fts3PrefixCompress("abX", 3, "Xbcdef", 6)   // returns 0
+*/
+static int fts3PrefixCompress(
+  const char *zPrev,              /* Buffer containing previous term */
+  int nPrev,                      /* Size of buffer zPrev in bytes */
+  const char *zNext,              /* Buffer containing next term */
+  int nNext                       /* Size of buffer zNext in bytes */
+){
+  int n;
+  for(n=0; n<nPrev && n<nNext && zPrev[n]==zNext[n]; n++);
+  assert_fts3_nc( n<nNext );
+  return n;
+}
+
+/*
+** Add term zTerm to the SegmentNode. It is guaranteed that zTerm is larger
+** (according to memcmp) than the previous term.
+*/
+static int fts3NodeAddTerm(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentNode **ppTree,           /* IN/OUT: SegmentNode handle */
+  int isCopyTerm,                 /* True if zTerm/nTerm is transient */
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm                       /* Size of term in bytes */
+){
+  SegmentNode *pTree = *ppTree;
+  int rc;
+  SegmentNode *pNew;
+
+  /* First try to append the term to the current node. Return early if
+  ** this is possible.
+  */
+  if( pTree ){
+    int nData = pTree->nData;     /* Current size of node in bytes */
+    int nReq = nData;             /* Required space after adding zTerm */
+    int nPrefix;                  /* Number of bytes of prefix compression */
+    int nSuffix;                  /* Suffix length */
+
+    nPrefix = fts3PrefixCompress(pTree->zTerm, pTree->nTerm, zTerm, nTerm);
+    nSuffix = nTerm-nPrefix;
+
+    /* If nSuffix is zero or less, then zTerm/nTerm must be a prefix of
+    ** pWriter->zTerm/pWriter->nTerm. i.e. must be equal to or less than when
+    ** compared with BINARY collation. This indicates corruption.  */
+    if( nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+
+    nReq += sqlite3Fts3VarintLen(nPrefix)+sqlite3Fts3VarintLen(nSuffix)+nSuffix;
+    if( nReq<=p->nNodeSize || !pTree->zTerm ){
+
+      if( nReq>p->nNodeSize ){
+        /* An unusual case: this is the first term to be added to the node
+        ** and the static node buffer (p->nNodeSize bytes) is not large
+        ** enough. Use a separately malloced buffer instead This wastes
+        ** p->nNodeSize bytes, but since this scenario only comes about when
+        ** the database contain two terms that share a prefix of almost 2KB,
+        ** this is not expected to be a serious problem.
+        */
+        assert( pTree->aData==(char *)&pTree[1] );
+        pTree->aData = (char *)sqlite3_malloc64(nReq);
+        if( !pTree->aData ){
+          return SQLITE_NOMEM;
+        }
+      }
+
+      if( pTree->zTerm ){
+        /* There is no prefix-length field for first term in a node */
+        nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nPrefix);
+      }
+
+      nData += sqlite3Fts3PutVarint(&pTree->aData[nData], nSuffix);
+      memcpy(&pTree->aData[nData], &zTerm[nPrefix], nSuffix);
+      pTree->nData = nData + nSuffix;
+      pTree->nEntry++;
+
+      if( isCopyTerm ){
+        if( pTree->nMalloc<nTerm ){
+          char *zNew = sqlite3_realloc64(pTree->zMalloc, (i64)nTerm*2);
+          if( !zNew ){
+            return SQLITE_NOMEM;
+          }
+          pTree->nMalloc = nTerm*2;
+          pTree->zMalloc = zNew;
+        }
+        pTree->zTerm = pTree->zMalloc;
+        memcpy(pTree->zTerm, zTerm, nTerm);
+        pTree->nTerm = nTerm;
+      }else{
+        pTree->zTerm = (char *)zTerm;
+        pTree->nTerm = nTerm;
+      }
+      return SQLITE_OK;
+    }
+  }
+
+  /* If control flows to here, it was not possible to append zTerm to the
+  ** current node. Create a new node (a right-sibling of the current node).
+  ** If this is the first node in the tree, the term is added to it.
+  **
+  ** Otherwise, the term is not added to the new node, it is left empty for
+  ** now. Instead, the term is inserted into the parent of pTree. If pTree
+  ** has no parent, one is created here.
+  */
+  pNew = (SegmentNode *)sqlite3_malloc64(sizeof(SegmentNode) + p->nNodeSize);
+  if( !pNew ){
+    return SQLITE_NOMEM;
+  }
+  memset(pNew, 0, sizeof(SegmentNode));
+  pNew->nData = 1 + FTS3_VARINT_MAX;
+  pNew->aData = (char *)&pNew[1];
+
+  if( pTree ){
+    SegmentNode *pParent = pTree->pParent;
+    rc = fts3NodeAddTerm(p, &pParent, isCopyTerm, zTerm, nTerm);
+    if( pTree->pParent==0 ){
+      pTree->pParent = pParent;
+    }
+    pTree->pRight = pNew;
+    pNew->pLeftmost = pTree->pLeftmost;
+    pNew->pParent = pParent;
+    pNew->zMalloc = pTree->zMalloc;
+    pNew->nMalloc = pTree->nMalloc;
+    pTree->zMalloc = 0;
+  }else{
+    pNew->pLeftmost = pNew;
+    rc = fts3NodeAddTerm(p, &pNew, isCopyTerm, zTerm, nTerm);
+  }
+
+  *ppTree = pNew;
+  return rc;
+}
+
+/*
+** Helper function for fts3NodeWrite().
+*/
+static int fts3TreeFinishNode(
+  SegmentNode *pTree,
+  int iHeight,
+  sqlite3_int64 iLeftChild
+){
+  int nStart;
+  assert( iHeight>=1 && iHeight<128 );
+  nStart = FTS3_VARINT_MAX - sqlite3Fts3VarintLen(iLeftChild);
+  pTree->aData[nStart] = (char)iHeight;
+  sqlite3Fts3PutVarint(&pTree->aData[nStart+1], iLeftChild);
+  return nStart;
+}
+
+/*
+** Write the buffer for the segment node pTree and all of its peers to the
+** database. Then call this function recursively to write the parent of
+** pTree and its peers to the database.
+**
+** Except, if pTree is a root node, do not write it to the database. Instead,
+** set output variables *paRoot and *pnRoot to contain the root node.
+**
+** If successful, SQLITE_OK is returned and output variable *piLast is
+** set to the largest blockid written to the database (or zero if no
+** blocks were written to the db). Otherwise, an SQLite error code is
+** returned.
+*/
+static int fts3NodeWrite(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentNode *pTree,             /* SegmentNode handle */
+  int iHeight,                    /* Height of this node in tree */
+  sqlite3_int64 iLeaf,            /* Block id of first leaf node */
+  sqlite3_int64 iFree,            /* Block id of next free slot in %_segments */
+  sqlite3_int64 *piLast,          /* OUT: Block id of last entry written */
+  char **paRoot,                  /* OUT: Data for root node */
+  int *pnRoot                     /* OUT: Size of root node in bytes */
+){
+  int rc = SQLITE_OK;
+
+  if( !pTree->pParent ){
+    /* Root node of the tree. */
+    int nStart = fts3TreeFinishNode(pTree, iHeight, iLeaf);
+    *piLast = iFree-1;
+    *pnRoot = pTree->nData - nStart;
+    *paRoot = &pTree->aData[nStart];
+  }else{
+    SegmentNode *pIter;
+    sqlite3_int64 iNextFree = iFree;
+    sqlite3_int64 iNextLeaf = iLeaf;
+    for(pIter=pTree->pLeftmost; pIter && rc==SQLITE_OK; pIter=pIter->pRight){
+      int nStart = fts3TreeFinishNode(pIter, iHeight, iNextLeaf);
+      int nWrite = pIter->nData - nStart;
+
+      rc = fts3WriteSegment(p, iNextFree, &pIter->aData[nStart], nWrite);
+      iNextFree++;
+      iNextLeaf += (pIter->nEntry+1);
+    }
+    if( rc==SQLITE_OK ){
+      assert( iNextLeaf==iFree );
+      rc = fts3NodeWrite(
+          p, pTree->pParent, iHeight+1, iFree, iNextFree, piLast, paRoot, pnRoot
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Free all memory allocations associated with the tree pTree.
+*/
+static void fts3NodeFree(SegmentNode *pTree){
+  if( pTree ){
+    SegmentNode *p = pTree->pLeftmost;
+    fts3NodeFree(p->pParent);
+    while( p ){
+      SegmentNode *pRight = p->pRight;
+      if( p->aData!=(char *)&p[1] ){
+        sqlite3_free(p->aData);
+      }
+      assert( pRight==0 || p->zMalloc==0 );
+      sqlite3_free(p->zMalloc);
+      sqlite3_free(p);
+      p = pRight;
+    }
+  }
+}
+
+/*
+** Add a term to the segment being constructed by the SegmentWriter object
+** *ppWriter. When adding the first term to a segment, *ppWriter should
+** be passed NULL. This function will allocate a new SegmentWriter object
+** and return it via the input/output variable *ppWriter in this case.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+*/
+static int fts3SegWriterAdd(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentWriter **ppWriter,       /* IN/OUT: SegmentWriter handle */
+  int isCopyTerm,                 /* True if buffer zTerm must be copied */
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm,                      /* Size of term in bytes */
+  const char *aDoclist,           /* Pointer to buffer containing doclist */
+  int nDoclist                    /* Size of doclist in bytes */
+){
+  int nPrefix;                    /* Size of term prefix in bytes */
+  int nSuffix;                    /* Size of term suffix in bytes */
+  i64 nReq;                       /* Number of bytes required on leaf page */
+  int nData;
+  SegmentWriter *pWriter = *ppWriter;
+
+  if( !pWriter ){
+    int rc;
+    sqlite3_stmt *pStmt;
+
+    /* Allocate the SegmentWriter structure */
+    pWriter = (SegmentWriter *)sqlite3_malloc64(sizeof(SegmentWriter));
+    if( !pWriter ) return SQLITE_NOMEM;
+    memset(pWriter, 0, sizeof(SegmentWriter));
+    *ppWriter = pWriter;
+
+    /* Allocate a buffer in which to accumulate data */
+    pWriter->aData = (char *)sqlite3_malloc64(p->nNodeSize);
+    if( !pWriter->aData ) return SQLITE_NOMEM;
+    pWriter->nSize = p->nNodeSize;
+
+    /* Find the next free blockid in the %_segments table */
+    rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pStmt, 0);
+    if( rc!=SQLITE_OK ) return rc;
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      pWriter->iFree = sqlite3_column_int64(pStmt, 0);
+      pWriter->iFirst = pWriter->iFree;
+    }
+    rc = sqlite3_reset(pStmt);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  nData = pWriter->nData;
+
+  nPrefix = fts3PrefixCompress(pWriter->zTerm, pWriter->nTerm, zTerm, nTerm);
+  nSuffix = nTerm-nPrefix;
+
+  /* If nSuffix is zero or less, then zTerm/nTerm must be a prefix of
+  ** pWriter->zTerm/pWriter->nTerm. i.e. must be equal to or less than when
+  ** compared with BINARY collation. This indicates corruption.  */
+  if( nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+
+  /* Figure out how many bytes are required by this new entry */
+  nReq = sqlite3Fts3VarintLen(nPrefix) +    /* varint containing prefix size */
+    sqlite3Fts3VarintLen(nSuffix) +         /* varint containing suffix size */
+    nSuffix +                               /* Term suffix */
+    sqlite3Fts3VarintLen(nDoclist) +        /* Size of doclist */
+    nDoclist;                               /* Doclist data */
+
+  if( nData>0 && nData+nReq>p->nNodeSize ){
+    int rc;
+
+    /* The current leaf node is full. Write it out to the database. */
+    if( pWriter->iFree==LARGEST_INT64 ) return FTS_CORRUPT_VTAB;
+    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, nData);
+    if( rc!=SQLITE_OK ) return rc;
+    p->nLeafAdd++;
+
+    /* Add the current term to the interior node tree. The term added to
+    ** the interior tree must:
+    **
+    **   a) be greater than the largest term on the leaf node just written
+    **      to the database (still available in pWriter->zTerm), and
+    **
+    **   b) be less than or equal to the term about to be added to the new
+    **      leaf node (zTerm/nTerm).
+    **
+    ** In other words, it must be the prefix of zTerm 1 byte longer than
+    ** the common prefix (if any) of zTerm and pWriter->zTerm.
+    */
+    assert( nPrefix<nTerm );
+    rc = fts3NodeAddTerm(p, &pWriter->pTree, isCopyTerm, zTerm, nPrefix+1);
+    if( rc!=SQLITE_OK ) return rc;
+
+    nData = 0;
+    pWriter->nTerm = 0;
+
+    nPrefix = 0;
+    nSuffix = nTerm;
+    nReq = 1 +                              /* varint containing prefix size */
+      sqlite3Fts3VarintLen(nTerm) +         /* varint containing suffix size */
+      nTerm +                               /* Term suffix */
+      sqlite3Fts3VarintLen(nDoclist) +      /* Size of doclist */
+      nDoclist;                             /* Doclist data */
+  }
+
+  /* Increase the total number of bytes written to account for the new entry. */
+  pWriter->nLeafData += nReq;
+
+  /* If the buffer currently allocated is too small for this entry, realloc
+  ** the buffer to make it large enough.
+  */
+  if( nReq>pWriter->nSize ){
+    char *aNew = sqlite3_realloc64(pWriter->aData, nReq);
+    if( !aNew ) return SQLITE_NOMEM;
+    pWriter->aData = aNew;
+    pWriter->nSize = nReq;
+  }
+  assert( nData+nReq<=pWriter->nSize );
+
+  /* Append the prefix-compressed term and doclist to the buffer. */
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nPrefix);
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nSuffix);
+  assert( nSuffix>0 );
+  memcpy(&pWriter->aData[nData], &zTerm[nPrefix], nSuffix);
+  nData += nSuffix;
+  nData += sqlite3Fts3PutVarint(&pWriter->aData[nData], nDoclist);
+  assert( nDoclist>0 );
+  memcpy(&pWriter->aData[nData], aDoclist, nDoclist);
+  pWriter->nData = nData + nDoclist;
+
+  /* Save the current term so that it can be used to prefix-compress the next.
+  ** If the isCopyTerm parameter is true, then the buffer pointed to by
+  ** zTerm is transient, so take a copy of the term data. Otherwise, just
+  ** store a copy of the pointer.
+  */
+  if( isCopyTerm ){
+    if( nTerm>pWriter->nMalloc ){
+      char *zNew = sqlite3_realloc64(pWriter->zMalloc, (i64)nTerm*2);
+      if( !zNew ){
+        return SQLITE_NOMEM;
+      }
+      pWriter->nMalloc = nTerm*2;
+      pWriter->zMalloc = zNew;
+      pWriter->zTerm = zNew;
+    }
+    assert( pWriter->zTerm==pWriter->zMalloc );
+    assert( nTerm>0 );
+    memcpy(pWriter->zTerm, zTerm, nTerm);
+  }else{
+    pWriter->zTerm = (char *)zTerm;
+  }
+  pWriter->nTerm = nTerm;
+
+  return SQLITE_OK;
+}
+
+/*
+** Flush all data associated with the SegmentWriter object pWriter to the
+** database. This function must be called after all terms have been added
+** to the segment using fts3SegWriterAdd(). If successful, SQLITE_OK is
+** returned. Otherwise, an SQLite error code.
+*/
+static int fts3SegWriterFlush(
+  Fts3Table *p,                   /* Virtual table handle */
+  SegmentWriter *pWriter,         /* SegmentWriter to flush to the db */
+  sqlite3_int64 iLevel,           /* Value for 'level' column of %_segdir */
+  int iIdx                        /* Value for 'idx' column of %_segdir */
+){
+  int rc;                         /* Return code */
+  if( pWriter->pTree ){
+    sqlite3_int64 iLast = 0;      /* Largest block id written to database */
+    sqlite3_int64 iLastLeaf;      /* Largest leaf block id written to db */
+    char *zRoot = NULL;           /* Pointer to buffer containing root node */
+    int nRoot = 0;                /* Size of buffer zRoot */
+
+    iLastLeaf = pWriter->iFree;
+    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, pWriter->nData);
+    if( rc==SQLITE_OK ){
+      rc = fts3NodeWrite(p, pWriter->pTree, 1,
+          pWriter->iFirst, pWriter->iFree, &iLast, &zRoot, &nRoot);
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3WriteSegdir(p, iLevel, iIdx,
+          pWriter->iFirst, iLastLeaf, iLast, pWriter->nLeafData, zRoot, nRoot);
+    }
+  }else{
+    /* The entire tree fits on the root node. Write it to the segdir table. */
+    rc = fts3WriteSegdir(p, iLevel, iIdx,
+        0, 0, 0, pWriter->nLeafData, pWriter->aData, pWriter->nData);
+  }
+  p->nLeafAdd++;
+  return rc;
+}
+
+/*
+** Release all memory held by the SegmentWriter object passed as the
+** first argument.
+*/
+static void fts3SegWriterFree(SegmentWriter *pWriter){
+  if( pWriter ){
+    sqlite3_free(pWriter->aData);
+    sqlite3_free(pWriter->zMalloc);
+    fts3NodeFree(pWriter->pTree);
+    sqlite3_free(pWriter);
+  }
+}
+
+/*
+** The first value in the apVal[] array is assumed to contain an integer.
+** This function tests if there exist any documents with docid values that
+** are different from that integer. i.e. if deleting the document with docid
+** pRowid would mean the FTS3 table were empty.
+**
+** If successful, *pisEmpty is set to true if the table is empty except for
+** document pRowid, or false otherwise, and SQLITE_OK is returned. If an
+** error occurs, an SQLite error code is returned.
+*/
+static int fts3IsEmpty(Fts3Table *p, sqlite3_value *pRowid, int *pisEmpty){
+  sqlite3_stmt *pStmt;
+  int rc;
+  if( p->zContentTbl ){
+    /* If using the content=xxx option, assume the table is never empty */
+    *pisEmpty = 0;
+    rc = SQLITE_OK;
+  }else{
+    rc = fts3SqlStmt(p, SQL_IS_EMPTY, &pStmt, &pRowid);
+    if( rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        *pisEmpty = sqlite3_column_int(pStmt, 0);
+      }
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+  return rc;
+}
+
+/*
+** Set *pnMax to the largest segment level in the database for the index
+** iIndex.
+**
+** Segment levels are stored in the 'level' column of the %_segdir table.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if not.
+*/
+static int fts3SegmentMaxLevel(
+  Fts3Table *p,
+  int iLangid,
+  int iIndex,
+  sqlite3_int64 *pnMax
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  /* Set pStmt to the compiled version of:
+  **
+  **   SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?
+  **
+  ** (1024 is actually the value of macro FTS3_SEGDIR_PREFIXLEVEL_STR).
+  */
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR_MAX_LEVEL, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  sqlite3_bind_int64(pStmt, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
+  sqlite3_bind_int64(pStmt, 2,
+      getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
+  );
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    *pnMax = sqlite3_column_int64(pStmt, 0);
+  }
+  return sqlite3_reset(pStmt);
+}
+
+/*
+** iAbsLevel is an absolute level that may be assumed to exist within
+** the database. This function checks if it is the largest level number
+** within its index. Assuming no error occurs, *pbMax is set to 1 if
+** iAbsLevel is indeed the largest level, or 0 otherwise, and SQLITE_OK
+** is returned. If an error occurs, an error code is returned and the
+** final value of *pbMax is undefined.
+*/
+static int fts3SegmentIsMaxLevel(Fts3Table *p, i64 iAbsLevel, int *pbMax){
+
+  /* Set pStmt to the compiled version of:
+  **
+  **   SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?
+  **
+  ** (1024 is actually the value of macro FTS3_SEGDIR_PREFIXLEVEL_STR).
+  */
+  sqlite3_stmt *pStmt;
+  int rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR_MAX_LEVEL, &pStmt, 0);
+  if( rc!=SQLITE_OK ) return rc;
+  sqlite3_bind_int64(pStmt, 1, iAbsLevel+1);
+  sqlite3_bind_int64(pStmt, 2,
+      (((u64)iAbsLevel/FTS3_SEGDIR_MAXLEVEL)+1) * FTS3_SEGDIR_MAXLEVEL
+  );
+
+  *pbMax = 0;
+  if( SQLITE_ROW==sqlite3_step(pStmt) ){
+    *pbMax = sqlite3_column_type(pStmt, 0)==SQLITE_NULL;
+  }
+  return sqlite3_reset(pStmt);
+}
+
+/*
+** Delete all entries in the %_segments table associated with the segment
+** opened with seg-reader pSeg. This function does not affect the contents
+** of the %_segdir table.
+*/
+static int fts3DeleteSegment(
+  Fts3Table *p,                   /* FTS table handle */
+  Fts3SegReader *pSeg             /* Segment to delete */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  if( pSeg->iStartBlock ){
+    sqlite3_stmt *pDelete;        /* SQL statement to delete rows */
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDelete, 1, pSeg->iStartBlock);
+      sqlite3_bind_int64(pDelete, 2, pSeg->iEndBlock);
+      sqlite3_step(pDelete);
+      rc = sqlite3_reset(pDelete);
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is used after merging multiple segments into a single large
+** segment to delete the old, now redundant, segment b-trees. Specifically,
+** it:
+**
+**   1) Deletes all %_segments entries for the segments associated with
+**      each of the SegReader objects in the array passed as the third
+**      argument, and
+**
+**   2) deletes all %_segdir entries with level iLevel, or all %_segdir
+**      entries regardless of level if (iLevel<0).
+**
+** SQLITE_OK is returned if successful, otherwise an SQLite error code.
+*/
+static int fts3DeleteSegdir(
+  Fts3Table *p,                   /* Virtual table handle */
+  int iLangid,                    /* Language id */
+  int iIndex,                     /* Index for p->aIndex */
+  int iLevel,                     /* Level of %_segdir entries to delete */
+  Fts3SegReader **apSegment,      /* Array of SegReader objects */
+  int nReader                     /* Size of array apSegment */
+){
+  int rc = SQLITE_OK;             /* Return Code */
+  int i;                          /* Iterator variable */
+  sqlite3_stmt *pDelete = 0;      /* SQL statement to delete rows */
+
+  for(i=0; rc==SQLITE_OK && i<nReader; i++){
+    rc = fts3DeleteSegment(p, apSegment[i]);
+  }
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  assert( iLevel>=0 || iLevel==FTS3_SEGCURSOR_ALL );
+  if( iLevel==FTS3_SEGCURSOR_ALL ){
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_RANGE, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDelete, 1, getAbsoluteLevel(p, iLangid, iIndex, 0));
+      sqlite3_bind_int64(pDelete, 2,
+          getAbsoluteLevel(p, iLangid, iIndex, FTS3_SEGDIR_MAXLEVEL-1)
+      );
+    }
+  }else{
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_LEVEL, &pDelete, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(
+          pDelete, 1, getAbsoluteLevel(p, iLangid, iIndex, iLevel)
+      );
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sqlite3_step(pDelete);
+    rc = sqlite3_reset(pDelete);
+  }
+
+  return rc;
+}
+
+/*
+** When this function is called, buffer *ppList (size *pnList bytes) contains
+** a position list that may (or may not) feature multiple columns. This
+** function adjusts the pointer *ppList and the length *pnList so that they
+** identify the subset of the position list that corresponds to column iCol.
+**
+** If there are no entries in the input position list for column iCol, then
+** *pnList is set to zero before returning.
+**
+** If parameter bZero is non-zero, then any part of the input list following
+** the end of the output list is zeroed before returning.
+*/
+static void fts3ColumnFilter(
+  int iCol,                       /* Column to filter on */
+  int bZero,                      /* Zero out anything following *ppList */
+  char **ppList,                  /* IN/OUT: Pointer to position list */
+  int *pnList                     /* IN/OUT: Size of buffer *ppList in bytes */
+){
+  char *pList = *ppList;
+  int nList = *pnList;
+  char *pEnd = &pList[nList];
+  int iCurrent = 0;
+  char *p = pList;
+
+  assert( iCol>=0 );
+  while( 1 ){
+    char c = 0;
+    while( p<pEnd && (c | *p)&0xFE ) c = *p++ & 0x80;
+
+    if( iCol==iCurrent ){
+      nList = (int)(p - pList);
+      break;
+    }
+
+    nList -= (int)(p - pList);
+    pList = p;
+    if( nList<=0 ){
+      break;
+    }
+    p = &pList[1];
+    p += fts3GetVarint32(p, &iCurrent);
+  }
+
+  if( bZero && (pEnd - &pList[nList])>0){
+    memset(&pList[nList], 0, pEnd - &pList[nList]);
+  }
+  *ppList = pList;
+  *pnList = nList;
+}
+
+/*
+** Cache data in the Fts3MultiSegReader.aBuffer[] buffer (overwriting any
+** existing data). Grow the buffer if required.
+**
+** If successful, return SQLITE_OK. Otherwise, if an OOM error is encountered
+** trying to resize the buffer, return SQLITE_NOMEM.
+*/
+static int fts3MsrBufferData(
+  Fts3MultiSegReader *pMsr,       /* Multi-segment-reader handle */
+  char *pList,
+  i64 nList
+){
+  if( (nList+FTS3_NODE_PADDING)>pMsr->nBuffer ){
+    char *pNew;
+    int nNew = nList*2 + FTS3_NODE_PADDING;
+    pNew = (char *)sqlite3_realloc64(pMsr->aBuffer, nNew);
+    if( !pNew ) return SQLITE_NOMEM;
+    pMsr->aBuffer = pNew;
+    pMsr->nBuffer = nNew;
+  }
+
+  assert( nList>0 );
+  memcpy(pMsr->aBuffer, pList, nList);
+  memset(&pMsr->aBuffer[nList], 0, FTS3_NODE_PADDING);
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrNext(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pMsr,       /* Multi-segment-reader handle */
+  sqlite3_int64 *piDocid,         /* OUT: Docid value */
+  char **paPoslist,               /* OUT: Pointer to position list */
+  int *pnPoslist                  /* OUT: Size of position list in bytes */
+){
+  int nMerge = pMsr->nAdvance;
+  Fts3SegReader **apSegment = pMsr->apSegment;
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
+    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
+  );
+
+  if( nMerge==0 ){
+    *paPoslist = 0;
+    return SQLITE_OK;
+  }
+
+  while( 1 ){
+    Fts3SegReader *pSeg;
+    pSeg = pMsr->apSegment[0];
+
+    if( pSeg->pOffsetList==0 ){
+      *paPoslist = 0;
+      break;
+    }else{
+      int rc;
+      char *pList;
+      int nList;
+      int j;
+      sqlite3_int64 iDocid = apSegment[0]->iDocid;
+
+      rc = fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
+      j = 1;
+      while( rc==SQLITE_OK
+        && j<nMerge
+        && apSegment[j]->pOffsetList
+        && apSegment[j]->iDocid==iDocid
+      ){
+        rc = fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
+        j++;
+      }
+      if( rc!=SQLITE_OK ) return rc;
+      fts3SegReaderSort(pMsr->apSegment, nMerge, j, xCmp);
+
+      if( nList>0 && fts3SegReaderIsPending(apSegment[0]) ){
+        rc = fts3MsrBufferData(pMsr, pList, (i64)nList+1);
+        if( rc!=SQLITE_OK ) return rc;
+        assert( (pMsr->aBuffer[nList] & 0xFE)==0x00 );
+        pList = pMsr->aBuffer;
+      }
+
+      if( pMsr->iColFilter>=0 ){
+        fts3ColumnFilter(pMsr->iColFilter, 1, &pList, &nList);
+      }
+
+      if( nList>0 ){
+        *paPoslist = pList;
+        *piDocid = iDocid;
+        *pnPoslist = nList;
+        break;
+      }
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+static int fts3SegReaderStart(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr,       /* Cursor object */
+  const char *zTerm,              /* Term searched for (or NULL) */
+  int nTerm                       /* Length of zTerm in bytes */
+){
+  int i;
+  int nSeg = pCsr->nSegment;
+
+  /* If the Fts3SegFilter defines a specific term (or term prefix) to search
+  ** for, then advance each segment iterator until it points to a term of
+  ** equal or greater value than the specified term. This prevents many
+  ** unnecessary merge/sort operations for the case where single segment
+  ** b-tree leaf nodes contain more than one term.
+  */
+  for(i=0; pCsr->bRestart==0 && i<pCsr->nSegment; i++){
+    int res = 0;
+    Fts3SegReader *pSeg = pCsr->apSegment[i];
+    do {
+      int rc = fts3SegReaderNext(p, pSeg, 0);
+      if( rc!=SQLITE_OK ) return rc;
+    }while( zTerm && (res = fts3SegReaderTermCmp(pSeg, zTerm, nTerm))<0 );
+
+    if( pSeg->bLookup && res!=0 ){
+      fts3SegReaderSetEof(pSeg);
+    }
+  }
+  fts3SegReaderSort(pCsr->apSegment, nSeg, nSeg, fts3SegReaderCmp);
+
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStart(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr,       /* Cursor object */
+  Fts3SegFilter *pFilter          /* Restrictions on range of iteration */
+){
+  pCsr->pFilter = pFilter;
+  return fts3SegReaderStart(p, pCsr, pFilter->zTerm, pFilter->nTerm);
+}
+
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrStart(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr,       /* Cursor object */
+  int iCol,                       /* Column to match on. */
+  const char *zTerm,              /* Term to iterate through a doclist for */
+  int nTerm                       /* Number of bytes in zTerm */
+){
+  int i;
+  int rc;
+  int nSegment = pCsr->nSegment;
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
+    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
+  );
+
+  assert( pCsr->pFilter==0 );
+  assert( zTerm && nTerm>0 );
+
+  /* Advance each segment iterator until it points to the term zTerm/nTerm. */
+  rc = fts3SegReaderStart(p, pCsr, zTerm, nTerm);
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Determine how many of the segments actually point to zTerm/nTerm. */
+  for(i=0; i<nSegment; i++){
+    Fts3SegReader *pSeg = pCsr->apSegment[i];
+    if( !pSeg->aNode || fts3SegReaderTermCmp(pSeg, zTerm, nTerm) ){
+      break;
+    }
+  }
+  pCsr->nAdvance = i;
+
+  /* Advance each of the segments to point to the first docid. */
+  for(i=0; i<pCsr->nAdvance; i++){
+    rc = fts3SegReaderFirstDocid(p, pCsr->apSegment[i]);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  fts3SegReaderSort(pCsr->apSegment, i, i, xCmp);
+
+  assert( iCol<0 || iCol<p->nColumn );
+  pCsr->iColFilter = iCol;
+
+  return SQLITE_OK;
+}
+
+/*
+** This function is called on a MultiSegReader that has been started using
+** sqlite3Fts3MsrIncrStart(). One or more calls to MsrIncrNext() may also
+** have been made. Calling this function puts the MultiSegReader in such
+** a state that if the next two calls are:
+**
+**   sqlite3Fts3SegReaderStart()
+**   sqlite3Fts3SegReaderStep()
+**
+** then the entire doclist for the term is available in
+** MultiSegReader.aDoclist/nDoclist.
+*/
+SQLITE_PRIVATE int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr){
+  int i;                          /* Used to iterate through segment-readers */
+
+  assert( pCsr->zTerm==0 );
+  assert( pCsr->nTerm==0 );
+  assert( pCsr->aDoclist==0 );
+  assert( pCsr->nDoclist==0 );
+
+  pCsr->nAdvance = 0;
+  pCsr->bRestart = 1;
+  for(i=0; i<pCsr->nSegment; i++){
+    pCsr->apSegment[i]->pOffsetList = 0;
+    pCsr->apSegment[i]->nOffsetList = 0;
+    pCsr->apSegment[i]->iDocid = 0;
+  }
+
+  return SQLITE_OK;
+}
+
+static int fts3GrowSegReaderBuffer(Fts3MultiSegReader *pCsr, i64 nReq){
+  if( nReq>pCsr->nBuffer ){
+    char *aNew;
+    pCsr->nBuffer = nReq*2;
+    aNew = sqlite3_realloc64(pCsr->aBuffer, pCsr->nBuffer);
+    if( !aNew ){
+      return SQLITE_NOMEM;
+    }
+    pCsr->aBuffer = aNew;
+  }
+  return SQLITE_OK;
+}
+
+
+SQLITE_PRIVATE int sqlite3Fts3SegReaderStep(
+  Fts3Table *p,                   /* Virtual table handle */
+  Fts3MultiSegReader *pCsr        /* Cursor object */
+){
+  int rc = SQLITE_OK;
+
+  int isIgnoreEmpty =  (pCsr->pFilter->flags & FTS3_SEGMENT_IGNORE_EMPTY);
+  int isRequirePos =   (pCsr->pFilter->flags & FTS3_SEGMENT_REQUIRE_POS);
+  int isColFilter =    (pCsr->pFilter->flags & FTS3_SEGMENT_COLUMN_FILTER);
+  int isPrefix =       (pCsr->pFilter->flags & FTS3_SEGMENT_PREFIX);
+  int isScan =         (pCsr->pFilter->flags & FTS3_SEGMENT_SCAN);
+  int isFirst =        (pCsr->pFilter->flags & FTS3_SEGMENT_FIRST);
+
+  Fts3SegReader **apSegment = pCsr->apSegment;
+  int nSegment = pCsr->nSegment;
+  Fts3SegFilter *pFilter = pCsr->pFilter;
+  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
+    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
+  );
+
+  if( pCsr->nSegment==0 ) return SQLITE_OK;
+
+  do {
+    int nMerge;
+    int i;
+
+    /* Advance the first pCsr->nAdvance entries in the apSegment[] array
+    ** forward. Then sort the list in order of current term again.
+    */
+    for(i=0; i<pCsr->nAdvance; i++){
+      Fts3SegReader *pSeg = apSegment[i];
+      if( pSeg->bLookup ){
+        fts3SegReaderSetEof(pSeg);
+      }else{
+        rc = fts3SegReaderNext(p, pSeg, 0);
+      }
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    fts3SegReaderSort(apSegment, nSegment, pCsr->nAdvance, fts3SegReaderCmp);
+    pCsr->nAdvance = 0;
+
+    /* If all the seg-readers are at EOF, we're finished. return SQLITE_OK. */
+    assert( rc==SQLITE_OK );
+    if( apSegment[0]->aNode==0 ) break;
+
+    pCsr->nTerm = apSegment[0]->nTerm;
+    pCsr->zTerm = apSegment[0]->zTerm;
+
+    /* If this is a prefix-search, and if the term that apSegment[0] points
+    ** to does not share a suffix with pFilter->zTerm/nTerm, then all
+    ** required callbacks have been made. In this case exit early.
+    **
+    ** Similarly, if this is a search for an exact match, and the first term
+    ** of segment apSegment[0] is not a match, exit early.
+    */
+    if( pFilter->zTerm && !isScan ){
+      if( pCsr->nTerm<pFilter->nTerm
+       || (!isPrefix && pCsr->nTerm>pFilter->nTerm)
+       || memcmp(pCsr->zTerm, pFilter->zTerm, pFilter->nTerm)
+      ){
+        break;
+      }
+    }
+
+    nMerge = 1;
+    while( nMerge<nSegment
+        && apSegment[nMerge]->aNode
+        && apSegment[nMerge]->nTerm==pCsr->nTerm
+        && 0==memcmp(pCsr->zTerm, apSegment[nMerge]->zTerm, pCsr->nTerm)
+    ){
+      nMerge++;
+    }
+
+    assert( isIgnoreEmpty || (isRequirePos && !isColFilter) );
+    if( nMerge==1
+     && !isIgnoreEmpty
+     && !isFirst
+     && (p->bDescIdx==0 || fts3SegReaderIsPending(apSegment[0])==0)
+    ){
+      pCsr->nDoclist = apSegment[0]->nDoclist;
+      if( fts3SegReaderIsPending(apSegment[0]) ){
+        rc = fts3MsrBufferData(pCsr, apSegment[0]->aDoclist,
+                               (i64)pCsr->nDoclist);
+        pCsr->aDoclist = pCsr->aBuffer;
+      }else{
+        pCsr->aDoclist = apSegment[0]->aDoclist;
+      }
+      if( rc==SQLITE_OK ) rc = SQLITE_ROW;
+    }else{
+      int nDoclist = 0;           /* Size of doclist */
+      sqlite3_int64 iPrev = 0;    /* Previous docid stored in doclist */
+
+      /* The current term of the first nMerge entries in the array
+      ** of Fts3SegReader objects is the same. The doclists must be merged
+      ** and a single term returned with the merged doclist.
+      */
+      for(i=0; i<nMerge; i++){
+        fts3SegReaderFirstDocid(p, apSegment[i]);
+      }
+      fts3SegReaderSort(apSegment, nMerge, nMerge, xCmp);
+      while( apSegment[0]->pOffsetList ){
+        int j;                    /* Number of segments that share a docid */
+        char *pList = 0;
+        int nList = 0;
+        int nByte;
+        sqlite3_int64 iDocid = apSegment[0]->iDocid;
+        fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
+        j = 1;
+        while( j<nMerge
+            && apSegment[j]->pOffsetList
+            && apSegment[j]->iDocid==iDocid
+        ){
+          fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
+          j++;
+        }
+
+        if( isColFilter ){
+          fts3ColumnFilter(pFilter->iCol, 0, &pList, &nList);
+        }
+
+        if( !isIgnoreEmpty || nList>0 ){
+
+          /* Calculate the 'docid' delta value to write into the merged
+          ** doclist. */
+          sqlite3_int64 iDelta;
+          if( p->bDescIdx && nDoclist>0 ){
+            if( iPrev<=iDocid ) return FTS_CORRUPT_VTAB;
+            iDelta = (i64)((u64)iPrev - (u64)iDocid);
+          }else{
+            if( nDoclist>0 && iPrev>=iDocid ) return FTS_CORRUPT_VTAB;
+            iDelta = (i64)((u64)iDocid - (u64)iPrev);
+          }
+
+          nByte = sqlite3Fts3VarintLen(iDelta) + (isRequirePos?nList+1:0);
+
+          rc = fts3GrowSegReaderBuffer(pCsr,
+                                   (i64)nByte+nDoclist+FTS3_NODE_PADDING);
+          if( rc ) return rc;
+
+          if( isFirst ){
+            char *a = &pCsr->aBuffer[nDoclist];
+            int nWrite;
+
+            nWrite = sqlite3Fts3FirstFilter(iDelta, pList, nList, a);
+            if( nWrite ){
+              iPrev = iDocid;
+              nDoclist += nWrite;
+            }
+          }else{
+            nDoclist += sqlite3Fts3PutVarint(&pCsr->aBuffer[nDoclist], iDelta);
+            iPrev = iDocid;
+            if( isRequirePos ){
+              memcpy(&pCsr->aBuffer[nDoclist], pList, nList);
+              nDoclist += nList;
+              pCsr->aBuffer[nDoclist++] = '\0';
+            }
+          }
+        }
+
+        fts3SegReaderSort(apSegment, nMerge, j, xCmp);
+      }
+      if( nDoclist>0 ){
+        rc = fts3GrowSegReaderBuffer(pCsr, (i64)nDoclist+FTS3_NODE_PADDING);
+        if( rc ) return rc;
+        memset(&pCsr->aBuffer[nDoclist], 0, FTS3_NODE_PADDING);
+        pCsr->aDoclist = pCsr->aBuffer;
+        pCsr->nDoclist = nDoclist;
+        rc = SQLITE_ROW;
+      }
+    }
+    pCsr->nAdvance = nMerge;
+  }while( rc==SQLITE_OK );
+
+  return rc;
+}
+
+
+SQLITE_PRIVATE void sqlite3Fts3SegReaderFinish(
+  Fts3MultiSegReader *pCsr       /* Cursor object */
+){
+  if( pCsr ){
+    int i;
+    for(i=0; i<pCsr->nSegment; i++){
+      sqlite3Fts3SegReaderFree(pCsr->apSegment[i]);
+    }
+    sqlite3_free(pCsr->apSegment);
+    sqlite3_free(pCsr->aBuffer);
+
+    pCsr->nSegment = 0;
+    pCsr->apSegment = 0;
+    pCsr->aBuffer = 0;
+  }
+}
+
+/*
+** Decode the "end_block" field, selected by column iCol of the SELECT
+** statement passed as the first argument.
+**
+** The "end_block" field may contain either an integer, or a text field
+** containing the text representation of two non-negative integers separated
+** by one or more space (0x20) characters. In the first case, set *piEndBlock
+** to the integer value and *pnByte to zero before returning. In the second,
+** set *piEndBlock to the first value and *pnByte to the second.
+*/
+static void fts3ReadEndBlockField(
+  sqlite3_stmt *pStmt,
+  int iCol,
+  i64 *piEndBlock,
+  i64 *pnByte
+){
+  const unsigned char *zText = sqlite3_column_text(pStmt, iCol);
+  if( zText ){
+    int i;
+    int iMul = 1;
+    u64 iVal = 0;
+    for(i=0; zText[i]>='0' && zText[i]<='9'; i++){
+      iVal = iVal*10 + (zText[i] - '0');
+    }
+    *piEndBlock = (i64)iVal;
+    while( zText[i]==' ' ) i++;
+    iVal = 0;
+    if( zText[i]=='-' ){
+      i++;
+      iMul = -1;
+    }
+    for(/* no-op */; zText[i]>='0' && zText[i]<='9'; i++){
+      iVal = iVal*10 + (zText[i] - '0');
+    }
+    *pnByte = ((i64)iVal * (i64)iMul);
+  }
+}
+
+
+/*
+** A segment of size nByte bytes has just been written to absolute level
+** iAbsLevel. Promote any segments that should be promoted as a result.
+*/
+static int fts3PromoteSegments(
+  Fts3Table *p,                   /* FTS table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level just updated */
+  sqlite3_int64 nByte             /* Size of new segment at iAbsLevel */
+){
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pRange;
+
+  rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_RANGE2, &pRange, 0);
+
+  if( rc==SQLITE_OK ){
+    int bOk = 0;
+    i64 iLast = (iAbsLevel/FTS3_SEGDIR_MAXLEVEL + 1) * FTS3_SEGDIR_MAXLEVEL - 1;
+    i64 nLimit = (nByte*3)/2;
+
+    /* Loop through all entries in the %_segdir table corresponding to
+    ** segments in this index on levels greater than iAbsLevel. If there is
+    ** at least one such segment, and it is possible to determine that all
+    ** such segments are smaller than nLimit bytes in size, they will be
+    ** promoted to level iAbsLevel.  */
+    sqlite3_bind_int64(pRange, 1, iAbsLevel+1);
+    sqlite3_bind_int64(pRange, 2, iLast);
+    while( SQLITE_ROW==sqlite3_step(pRange) ){
+      i64 nSize = 0, dummy;
+      fts3ReadEndBlockField(pRange, 2, &dummy, &nSize);
+      if( nSize<=0 || nSize>nLimit ){
+        /* If nSize==0, then the %_segdir.end_block field does not not
+        ** contain a size value. This happens if it was written by an
+        ** old version of FTS. In this case it is not possible to determine
+        ** the size of the segment, and so segment promotion does not
+        ** take place.  */
+        bOk = 0;
+        break;
+      }
+      bOk = 1;
+    }
+    rc = sqlite3_reset(pRange);
+
+    if( bOk ){
+      int iIdx = 0;
+      sqlite3_stmt *pUpdate1 = 0;
+      sqlite3_stmt *pUpdate2 = 0;
+
+      if( rc==SQLITE_OK ){
+        rc = fts3SqlStmt(p, SQL_UPDATE_LEVEL_IDX, &pUpdate1, 0);
+      }
+      if( rc==SQLITE_OK ){
+        rc = fts3SqlStmt(p, SQL_UPDATE_LEVEL, &pUpdate2, 0);
+      }
+
+      if( rc==SQLITE_OK ){
+
+        /* Loop through all %_segdir entries for segments in this index with
+        ** levels equal to or greater than iAbsLevel. As each entry is visited,
+        ** updated it to set (level = -1) and (idx = N), where N is 0 for the
+        ** oldest segment in the range, 1 for the next oldest, and so on.
+        **
+        ** In other words, move all segments being promoted to level -1,
+        ** setting the "idx" fields as appropriate to keep them in the same
+        ** order. The contents of level -1 (which is never used, except
+        ** transiently here), will be moved back to level iAbsLevel below.  */
+        sqlite3_bind_int64(pRange, 1, iAbsLevel);
+        while( SQLITE_ROW==sqlite3_step(pRange) ){
+          sqlite3_bind_int(pUpdate1, 1, iIdx++);
+          sqlite3_bind_int(pUpdate1, 2, sqlite3_column_int(pRange, 0));
+          sqlite3_bind_int(pUpdate1, 3, sqlite3_column_int(pRange, 1));
+          sqlite3_step(pUpdate1);
+          rc = sqlite3_reset(pUpdate1);
+          if( rc!=SQLITE_OK ){
+            sqlite3_reset(pRange);
+            break;
+          }
+        }
+      }
+      if( rc==SQLITE_OK ){
+        rc = sqlite3_reset(pRange);
+      }
+
+      /* Move level -1 to level iAbsLevel */
+      if( rc==SQLITE_OK ){
+        sqlite3_bind_int64(pUpdate2, 1, iAbsLevel);
+        sqlite3_step(pUpdate2);
+        rc = sqlite3_reset(pUpdate2);
+      }
+    }
+  }
+
+
+  return rc;
+}
+
+/*
+** Merge all level iLevel segments in the database into a single
+** iLevel+1 segment. Or, if iLevel<0, merge all segments into a
+** single segment with a level equal to the numerically largest level
+** currently present in the database.
+**
+** If this function is called with iLevel<0, but there is only one
+** segment in the database, SQLITE_DONE is returned immediately.
+** Otherwise, if successful, SQLITE_OK is returned. If an error occurs,
+** an SQLite error code is returned.
+*/
+static int fts3SegmentMerge(
+  Fts3Table *p,
+  int iLangid,                    /* Language id to merge */
+  int iIndex,                     /* Index in p->aIndex[] to merge */
+  int iLevel                      /* Level to merge */
+){
+  int rc;                         /* Return code */
+  int iIdx = 0;                   /* Index of new segment */
+  sqlite3_int64 iNewLevel = 0;    /* Level/index to create new segment at */
+  SegmentWriter *pWriter = 0;     /* Used to write the new, merged, segment */
+  Fts3SegFilter filter;           /* Segment term filter condition */
+  Fts3MultiSegReader csr;         /* Cursor to iterate through level(s) */
+  int bIgnoreEmpty = 0;           /* True to ignore empty segments */
+  i64 iMaxLevel = 0;              /* Max level number for this index/langid */
+
+  assert( iLevel==FTS3_SEGCURSOR_ALL
+       || iLevel==FTS3_SEGCURSOR_PENDING
+       || iLevel>=0
+  );
+  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
+  assert( iIndex>=0 && iIndex<p->nIndex );
+
+  rc = sqlite3Fts3SegReaderCursor(p, iLangid, iIndex, iLevel, 0, 0, 1, 0, &csr);
+  if( rc!=SQLITE_OK || csr.nSegment==0 ) goto finished;
+
+  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
+    rc = fts3SegmentMaxLevel(p, iLangid, iIndex, &iMaxLevel);
+    if( rc!=SQLITE_OK ) goto finished;
+  }
+
+  if( iLevel==FTS3_SEGCURSOR_ALL ){
+    /* This call is to merge all segments in the database to a single
+    ** segment. The level of the new segment is equal to the numerically
+    ** greatest segment level currently present in the database for this
+    ** index. The idx of the new segment is always 0.  */
+    if( csr.nSegment==1 && 0==fts3SegReaderIsPending(csr.apSegment[0]) ){
+      rc = SQLITE_DONE;
+      goto finished;
+    }
+    iNewLevel = iMaxLevel;
+    bIgnoreEmpty = 1;
+
+  }else{
+    /* This call is to merge all segments at level iLevel. find the next
+    ** available segment index at level iLevel+1. The call to
+    ** fts3AllocateSegdirIdx() will merge the segments at level iLevel+1 to
+    ** a single iLevel+2 segment if necessary.  */
+    assert( FTS3_SEGCURSOR_PENDING==-1 );
+    iNewLevel = getAbsoluteLevel(p, iLangid, iIndex, iLevel+1);
+    rc = fts3AllocateSegdirIdx(p, iLangid, iIndex, iLevel+1, &iIdx);
+    bIgnoreEmpty = (iLevel!=FTS3_SEGCURSOR_PENDING) && (iNewLevel>iMaxLevel);
+  }
+  if( rc!=SQLITE_OK ) goto finished;
+
+  assert( csr.nSegment>0 );
+  assert_fts3_nc( iNewLevel>=getAbsoluteLevel(p, iLangid, iIndex, 0) );
+  assert_fts3_nc(
+    iNewLevel<getAbsoluteLevel(p, iLangid, iIndex,FTS3_SEGDIR_MAXLEVEL)
+  );
+
+  memset(&filter, 0, sizeof(Fts3SegFilter));
+  filter.flags = FTS3_SEGMENT_REQUIRE_POS;
+  filter.flags |= (bIgnoreEmpty ? FTS3_SEGMENT_IGNORE_EMPTY : 0);
+
+  rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
+  while( SQLITE_OK==rc ){
+    rc = sqlite3Fts3SegReaderStep(p, &csr);
+    if( rc!=SQLITE_ROW ) break;
+    rc = fts3SegWriterAdd(p, &pWriter, 1,
+        csr.zTerm, csr.nTerm, csr.aDoclist, csr.nDoclist);
+  }
+  if( rc!=SQLITE_OK ) goto finished;
+  assert_fts3_nc( pWriter || bIgnoreEmpty );
+
+  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
+    rc = fts3DeleteSegdir(
+        p, iLangid, iIndex, iLevel, csr.apSegment, csr.nSegment
+    );
+    if( rc!=SQLITE_OK ) goto finished;
+  }
+  if( pWriter ){
+    rc = fts3SegWriterFlush(p, pWriter, iNewLevel, iIdx);
+    if( rc==SQLITE_OK ){
+      if( iLevel==FTS3_SEGCURSOR_PENDING || iNewLevel<iMaxLevel ){
+        rc = fts3PromoteSegments(p, iNewLevel, pWriter->nLeafData);
+      }
+    }
+  }
+
+ finished:
+  fts3SegWriterFree(pWriter);
+  sqlite3Fts3SegReaderFinish(&csr);
+  return rc;
+}
+
+
+/*
+** Flush the contents of pendingTerms to level 0 segments.
+*/
+SQLITE_PRIVATE int sqlite3Fts3PendingTermsFlush(Fts3Table *p){
+  int rc = SQLITE_OK;
+  int i;
+
+  for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
+    rc = fts3SegmentMerge(p, p->iPrevLangid, i, FTS3_SEGCURSOR_PENDING);
+    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  }
+
+  /* Determine the auto-incr-merge setting if unknown.  If enabled,
+  ** estimate the number of leaf blocks of content to be written
+  */
+  if( rc==SQLITE_OK && p->bHasStat
+   && p->nAutoincrmerge==0xff && p->nLeafAdd>0
+  ){
+    sqlite3_stmt *pStmt = 0;
+    rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int(pStmt, 1, FTS_STAT_AUTOINCRMERGE);
+      rc = sqlite3_step(pStmt);
+      if( rc==SQLITE_ROW ){
+        p->nAutoincrmerge = sqlite3_column_int(pStmt, 0);
+        if( p->nAutoincrmerge==1 ) p->nAutoincrmerge = 8;
+      }else if( rc==SQLITE_DONE ){
+        p->nAutoincrmerge = 0;
+      }
+      rc = sqlite3_reset(pStmt);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sqlite3Fts3PendingTermsClear(p);
+  }
+  return rc;
+}
+
+/*
+** Encode N integers as varints into a blob.
+*/
+static void fts3EncodeIntArray(
+  int N,             /* The number of integers to encode */
+  u32 *a,            /* The integer values */
+  char *zBuf,        /* Write the BLOB here */
+  int *pNBuf         /* Write number of bytes if zBuf[] used here */
+){
+  int i, j;
+  for(i=j=0; i<N; i++){
+    j += sqlite3Fts3PutVarint(&zBuf[j], (sqlite3_int64)a[i]);
+  }
+  *pNBuf = j;
+}
+
+/*
+** Decode a blob of varints into N integers
+*/
+static void fts3DecodeIntArray(
+  int N,             /* The number of integers to decode */
+  u32 *a,            /* Write the integer values */
+  const char *zBuf,  /* The BLOB containing the varints */
+  int nBuf           /* size of the BLOB */
+){
+  int i = 0;
+  if( nBuf && (zBuf[nBuf-1]&0x80)==0 ){
+    int j;
+    for(i=j=0; i<N && j<nBuf; i++){
+      sqlite3_int64 x;
+      j += sqlite3Fts3GetVarint(&zBuf[j], &x);
+      a[i] = (u32)(x & 0xffffffff);
+    }
+  }
+  while( i<N ) a[i++] = 0;
+}
+
+/*
+** Insert the sizes (in tokens) for each column of the document
+** with docid equal to p->iPrevDocid.  The sizes are encoded as
+** a blob of varints.
+*/
+static void fts3InsertDocsize(
+  int *pRC,                       /* Result code */
+  Fts3Table *p,                   /* Table into which to insert */
+  u32 *aSz                        /* Sizes of each column, in tokens */
+){
+  char *pBlob;             /* The BLOB encoding of the document size */
+  int nBlob;               /* Number of bytes in the BLOB */
+  sqlite3_stmt *pStmt;     /* Statement used to insert the encoding */
+  int rc;                  /* Result code from subfunctions */
+
+  if( *pRC ) return;
+  pBlob = sqlite3_malloc64( 10*(sqlite3_int64)p->nColumn );
+  if( pBlob==0 ){
+    *pRC = SQLITE_NOMEM;
+    return;
+  }
+  fts3EncodeIntArray(p->nColumn, aSz, pBlob, &nBlob);
+  rc = fts3SqlStmt(p, SQL_REPLACE_DOCSIZE, &pStmt, 0);
+  if( rc ){
+    sqlite3_free(pBlob);
+    *pRC = rc;
+    return;
+  }
+  sqlite3_bind_int64(pStmt, 1, p->iPrevDocid);
+  sqlite3_bind_blob(pStmt, 2, pBlob, nBlob, sqlite3_free);
+  sqlite3_step(pStmt);
+  *pRC = sqlite3_reset(pStmt);
+}
+
+/*
+** Record 0 of the %_stat table contains a blob consisting of N varints,
+** where N is the number of user defined columns in the fts3 table plus
+** two. If nCol is the number of user defined columns, then values of the
+** varints are set as follows:
+**
+**   Varint 0:       Total number of rows in the table.
+**
+**   Varint 1..nCol: For each column, the total number of tokens stored in
+**                   the column for all rows of the table.
+**
+**   Varint 1+nCol:  The total size, in bytes, of all text values in all
+**                   columns of all rows of the table.
+**
+*/
+static void fts3UpdateDocTotals(
+  int *pRC,                       /* The result code */
+  Fts3Table *p,                   /* Table being updated */
+  u32 *aSzIns,                    /* Size increases */
+  u32 *aSzDel,                    /* Size decreases */
+  int nChng                       /* Change in the number of documents */
+){
+  char *pBlob;             /* Storage for BLOB written into %_stat */
+  int nBlob;               /* Size of BLOB written into %_stat */
+  u32 *a;                  /* Array of integers that becomes the BLOB */
+  sqlite3_stmt *pStmt;     /* Statement for reading and writing */
+  int i;                   /* Loop counter */
+  int rc;                  /* Result code from subfunctions */
+
+  const int nStat = p->nColumn+2;
+
+  if( *pRC ) return;
+  a = sqlite3_malloc64( (sizeof(u32)+10)*(sqlite3_int64)nStat );
+  if( a==0 ){
+    *pRC = SQLITE_NOMEM;
+    return;
+  }
+  pBlob = (char*)&a[nStat];
+  rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pStmt, 0);
+  if( rc ){
+    sqlite3_free(a);
+    *pRC = rc;
+    return;
+  }
+  sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
+  if( sqlite3_step(pStmt)==SQLITE_ROW ){
+    fts3DecodeIntArray(nStat, a,
+         sqlite3_column_blob(pStmt, 0),
+         sqlite3_column_bytes(pStmt, 0));
+  }else{
+    memset(a, 0, sizeof(u32)*(nStat) );
+  }
+  rc = sqlite3_reset(pStmt);
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(a);
+    *pRC = rc;
+    return;
+  }
+  if( nChng<0 && a[0]<(u32)(-nChng) ){
+    a[0] = 0;
+  }else{
+    a[0] += nChng;
+  }
+  for(i=0; i<p->nColumn+1; i++){
+    u32 x = a[i+1];
+    if( x+aSzIns[i] < aSzDel[i] ){
+      x = 0;
+    }else{
+      x = x + aSzIns[i] - aSzDel[i];
+    }
+    a[i+1] = x;
+  }
+  fts3EncodeIntArray(nStat, a, pBlob, &nBlob);
+  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pStmt, 0);
+  if( rc ){
+    sqlite3_free(a);
+    *pRC = rc;
+    return;
+  }
+  sqlite3_bind_int(pStmt, 1, FTS_STAT_DOCTOTAL);
+  sqlite3_bind_blob(pStmt, 2, pBlob, nBlob, SQLITE_STATIC);
+  sqlite3_step(pStmt);
+  *pRC = sqlite3_reset(pStmt);
+  sqlite3_bind_null(pStmt, 2);
+  sqlite3_free(a);
+}
+
+/*
+** Merge the entire database so that there is one segment for each
+** iIndex/iLangid combination.
+*/
+static int fts3DoOptimize(Fts3Table *p, int bReturnDone){
+  int bSeenDone = 0;
+  int rc;
+  sqlite3_stmt *pAllLangid = 0;
+
+  rc = sqlite3Fts3PendingTermsFlush(p);
+  if( rc==SQLITE_OK ){
+    rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
+  }
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int(pAllLangid, 1, p->iPrevLangid);
+    sqlite3_bind_int(pAllLangid, 2, p->nIndex);
+    while( sqlite3_step(pAllLangid)==SQLITE_ROW ){
+      int i;
+      int iLangid = sqlite3_column_int(pAllLangid, 0);
+      for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
+        rc = fts3SegmentMerge(p, iLangid, i, FTS3_SEGCURSOR_ALL);
+        if( rc==SQLITE_DONE ){
+          bSeenDone = 1;
+          rc = SQLITE_OK;
+        }
+      }
+    }
+    rc2 = sqlite3_reset(pAllLangid);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  sqlite3Fts3SegmentsClose(p);
+
+  return (rc==SQLITE_OK && bReturnDone && bSeenDone) ? SQLITE_DONE : rc;
+}
+
+/*
+** This function is called when the user executes the following statement:
+**
+**     INSERT INTO <tbl>(<tbl>) VALUES('rebuild');
+**
+** The entire FTS index is discarded and rebuilt. If the table is one
+** created using the content=xxx option, then the new index is based on
+** the current contents of the xxx table. Otherwise, it is rebuilt based
+** on the contents of the %_content table.
+*/
+static int fts3DoRebuild(Fts3Table *p){
+  int rc;                         /* Return Code */
+
+  rc = fts3DeleteAll(p, 0);
+  if( rc==SQLITE_OK ){
+    u32 *aSz = 0;
+    u32 *aSzIns = 0;
+    u32 *aSzDel = 0;
+    sqlite3_stmt *pStmt = 0;
+    int nEntry = 0;
+
+    /* Compose and prepare an SQL statement to loop through the content table */
+    char *zSql = sqlite3_mprintf("SELECT %s" , p->zReadExprlist);
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
+      sqlite3_free(zSql);
+    }
+
+    if( rc==SQLITE_OK ){
+      sqlite3_int64 nByte = sizeof(u32) * ((sqlite3_int64)p->nColumn+1)*3;
+      aSz = (u32 *)sqlite3_malloc64(nByte);
+      if( aSz==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(aSz, 0, nByte);
+        aSzIns = &aSz[p->nColumn+1];
+        aSzDel = &aSzIns[p->nColumn+1];
+      }
+    }
+
+    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      int iCol;
+      int iLangid = langidFromSelect(p, pStmt);
+      rc = fts3PendingTermsDocid(p, 0, iLangid, sqlite3_column_int64(pStmt, 0));
+      memset(aSz, 0, sizeof(aSz[0]) * (p->nColumn+1));
+      for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
+        if( p->abNotindexed[iCol]==0 ){
+          const char *z = (const char *) sqlite3_column_text(pStmt, iCol+1);
+          rc = fts3PendingTermsAdd(p, iLangid, z, iCol, &aSz[iCol]);
+          aSz[p->nColumn] += sqlite3_column_bytes(pStmt, iCol+1);
+        }
+      }
+      if( p->bHasDocsize ){
+        fts3InsertDocsize(&rc, p, aSz);
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3_finalize(pStmt);
+        pStmt = 0;
+      }else{
+        nEntry++;
+        for(iCol=0; iCol<=p->nColumn; iCol++){
+          aSzIns[iCol] += aSz[iCol];
+        }
+      }
+    }
+    if( p->bFts4 ){
+      fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nEntry);
+    }
+    sqlite3_free(aSz);
+
+    if( pStmt ){
+      int rc2 = sqlite3_finalize(pStmt);
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+  }
+
+  return rc;
+}
+
+
+/*
+** This function opens a cursor used to read the input data for an
+** incremental merge operation. Specifically, it opens a cursor to scan
+** the oldest nSeg segments (idx=0 through idx=(nSeg-1)) in absolute
+** level iAbsLevel.
+*/
+static int fts3IncrmergeCsr(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level to open */
+  int nSeg,                       /* Number of segments to merge */
+  Fts3MultiSegReader *pCsr        /* Cursor object to populate */
+){
+  int rc;                         /* Return Code */
+  sqlite3_stmt *pStmt = 0;        /* Statement used to read %_segdir entry */
+  sqlite3_int64 nByte;            /* Bytes allocated at pCsr->apSegment[] */
+
+  /* Allocate space for the Fts3MultiSegReader.aCsr[] array */
+  memset(pCsr, 0, sizeof(*pCsr));
+  nByte = sizeof(Fts3SegReader *) * nSeg;
+  pCsr->apSegment = (Fts3SegReader **)sqlite3_malloc64(nByte);
+
+  if( pCsr->apSegment==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    memset(pCsr->apSegment, 0, nByte);
+    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
+  }
+  if( rc==SQLITE_OK ){
+    int i;
+    int rc2;
+    sqlite3_bind_int64(pStmt, 1, iAbsLevel);
+    assert( pCsr->nSegment==0 );
+    for(i=0; rc==SQLITE_OK && sqlite3_step(pStmt)==SQLITE_ROW && i<nSeg; i++){
+      rc = sqlite3Fts3SegReaderNew(i, 0,
+          sqlite3_column_int64(pStmt, 1),        /* segdir.start_block */
+          sqlite3_column_int64(pStmt, 2),        /* segdir.leaves_end_block */
+          sqlite3_column_int64(pStmt, 3),        /* segdir.end_block */
+          sqlite3_column_blob(pStmt, 4),         /* segdir.root */
+          sqlite3_column_bytes(pStmt, 4),        /* segdir.root */
+          &pCsr->apSegment[i]
+      );
+      pCsr->nSegment++;
+    }
+    rc2 = sqlite3_reset(pStmt);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  return rc;
+}
+
+typedef struct IncrmergeWriter IncrmergeWriter;
+typedef struct NodeWriter NodeWriter;
+typedef struct Blob Blob;
+typedef struct NodeReader NodeReader;
+
+/*
+** An instance of the following structure is used as a dynamic buffer
+** to build up nodes or other blobs of data in.
+**
+** The function blobGrowBuffer() is used to extend the allocation.
+*/
+struct Blob {
+  char *a;                        /* Pointer to allocation */
+  int n;                          /* Number of valid bytes of data in a[] */
+  int nAlloc;                     /* Allocated size of a[] (nAlloc>=n) */
+};
+
+/*
+** This structure is used to build up buffers containing segment b-tree
+** nodes (blocks).
+*/
+struct NodeWriter {
+  sqlite3_int64 iBlock;           /* Current block id */
+  Blob key;                       /* Last key written to the current block */
+  Blob block;                     /* Current block image */
+};
+
+/*
+** An object of this type contains the state required to create or append
+** to an appendable b-tree segment.
+*/
+struct IncrmergeWriter {
+  int nLeafEst;                   /* Space allocated for leaf blocks */
+  int nWork;                      /* Number of leaf pages flushed */
+  sqlite3_int64 iAbsLevel;        /* Absolute level of input segments */
+  int iIdx;                       /* Index of *output* segment in iAbsLevel+1 */
+  sqlite3_int64 iStart;           /* Block number of first allocated block */
+  sqlite3_int64 iEnd;             /* Block number of last allocated block */
+  sqlite3_int64 nLeafData;        /* Bytes of leaf page data so far */
+  u8 bNoLeafData;                 /* If true, store 0 for segment size */
+  NodeWriter aNodeWriter[FTS_MAX_APPENDABLE_HEIGHT];
+};
+
+/*
+** An object of the following type is used to read data from a single
+** FTS segment node. See the following functions:
+**
+**     nodeReaderInit()
+**     nodeReaderNext()
+**     nodeReaderRelease()
+*/
+struct NodeReader {
+  const char *aNode;
+  int nNode;
+  int iOff;                       /* Current offset within aNode[] */
+
+  /* Output variables. Containing the current node entry. */
+  sqlite3_int64 iChild;           /* Pointer to child node */
+  Blob term;                      /* Current term */
+  const char *aDoclist;           /* Pointer to doclist */
+  int nDoclist;                   /* Size of doclist in bytes */
+};
+
+/*
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, if the allocation at pBlob->a is not already at least nMin
+** bytes in size, extend (realloc) it to be so.
+**
+** If an OOM error occurs, set *pRc to SQLITE_NOMEM and leave pBlob->a
+** unmodified. Otherwise, if the allocation succeeds, update pBlob->nAlloc
+** to reflect the new size of the pBlob->a[] buffer.
+*/
+static void blobGrowBuffer(Blob *pBlob, int nMin, int *pRc){
+  if( *pRc==SQLITE_OK && nMin>pBlob->nAlloc ){
+    int nAlloc = nMin;
+    char *a = (char *)sqlite3_realloc64(pBlob->a, nAlloc);
+    if( a ){
+      pBlob->nAlloc = nAlloc;
+      pBlob->a = a;
+    }else{
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+}
+
+/*
+** Attempt to advance the node-reader object passed as the first argument to
+** the next entry on the node.
+**
+** Return an error code if an error occurs (SQLITE_NOMEM is possible).
+** Otherwise return SQLITE_OK. If there is no next entry on the node
+** (e.g. because the current entry is the last) set NodeReader->aNode to
+** NULL to indicate EOF. Otherwise, populate the NodeReader structure output
+** variables for the new entry.
+*/
+static int nodeReaderNext(NodeReader *p){
+  int bFirst = (p->term.n==0);    /* True for first term on the node */
+  int nPrefix = 0;                /* Bytes to copy from previous term */
+  int nSuffix = 0;                /* Bytes to append to the prefix */
+  int rc = SQLITE_OK;             /* Return code */
+
+  assert( p->aNode );
+  if( p->iChild && bFirst==0 ) p->iChild++;
+  if( p->iOff>=p->nNode ){
+    /* EOF */
+    p->aNode = 0;
+  }else{
+    if( bFirst==0 ){
+      p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &nPrefix);
+    }
+    p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &nSuffix);
+
+    if( nPrefix>p->term.n || nSuffix>p->nNode-p->iOff || nSuffix==0 ){
+      return FTS_CORRUPT_VTAB;
+    }
+    blobGrowBuffer(&p->term, nPrefix+nSuffix, &rc);
+    if( rc==SQLITE_OK && ALWAYS(p->term.a!=0) ){
+      memcpy(&p->term.a[nPrefix], &p->aNode[p->iOff], nSuffix);
+      p->term.n = nPrefix+nSuffix;
+      p->iOff += nSuffix;
+      if( p->iChild==0 ){
+        p->iOff += fts3GetVarint32(&p->aNode[p->iOff], &p->nDoclist);
+        if( (p->nNode-p->iOff)<p->nDoclist ){
+          return FTS_CORRUPT_VTAB;
+        }
+        p->aDoclist = &p->aNode[p->iOff];
+        p->iOff += p->nDoclist;
+      }
+    }
+  }
+
+  assert_fts3_nc( p->iOff<=p->nNode );
+  return rc;
+}
+
+/*
+** Release all dynamic resources held by node-reader object *p.
+*/
+static void nodeReaderRelease(NodeReader *p){
+  sqlite3_free(p->term.a);
+}
+
+/*
+** Initialize a node-reader object to read the node in buffer aNode/nNode.
+**
+** If successful, SQLITE_OK is returned and the NodeReader object set to
+** point to the first entry on the node (if any). Otherwise, an SQLite
+** error code is returned.
+*/
+static int nodeReaderInit(NodeReader *p, const char *aNode, int nNode){
+  memset(p, 0, sizeof(NodeReader));
+  p->aNode = aNode;
+  p->nNode = nNode;
+
+  /* Figure out if this is a leaf or an internal node. */
+  if( aNode && aNode[0] ){
+    /* An internal node. */
+    p->iOff = 1 + sqlite3Fts3GetVarint(&p->aNode[1], &p->iChild);
+  }else{
+    p->iOff = 1;
+  }
+
+  return aNode ? nodeReaderNext(p) : SQLITE_OK;
+}
+
+/*
+** This function is called while writing an FTS segment each time a leaf o
+** node is finished and written to disk. The key (zTerm/nTerm) is guaranteed
+** to be greater than the largest key on the node just written, but smaller
+** than or equal to the first key that will be written to the next leaf
+** node.
+**
+** The block id of the leaf node just written to disk may be found in
+** (pWriter->aNodeWriter[0].iBlock) when this function is called.
+*/
+static int fts3IncrmergePush(
+  Fts3Table *p,                   /* Fts3 table handle */
+  IncrmergeWriter *pWriter,       /* Writer object */
+  const char *zTerm,              /* Term to write to internal node */
+  int nTerm                       /* Bytes at zTerm */
+){
+  sqlite3_int64 iPtr = pWriter->aNodeWriter[0].iBlock;
+  int iLayer;
+
+  assert( nTerm>0 );
+  for(iLayer=1; ALWAYS(iLayer<FTS_MAX_APPENDABLE_HEIGHT); iLayer++){
+    sqlite3_int64 iNextPtr = 0;
+    NodeWriter *pNode = &pWriter->aNodeWriter[iLayer];
+    int rc = SQLITE_OK;
+    int nPrefix;
+    int nSuffix;
+    int nSpace;
+
+    /* Figure out how much space the key will consume if it is written to
+    ** the current node of layer iLayer. Due to the prefix compression,
+    ** the space required changes depending on which node the key is to
+    ** be added to.  */
+    nPrefix = fts3PrefixCompress(pNode->key.a, pNode->key.n, zTerm, nTerm);
+    nSuffix = nTerm - nPrefix;
+    if(nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+    nSpace  = sqlite3Fts3VarintLen(nPrefix);
+    nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
+
+    if( pNode->key.n==0 || (pNode->block.n + nSpace)<=p->nNodeSize ){
+      /* If the current node of layer iLayer contains zero keys, or if adding
+      ** the key to it will not cause it to grow to larger than nNodeSize
+      ** bytes in size, write the key here.  */
+
+      Blob *pBlk = &pNode->block;
+      if( pBlk->n==0 ){
+        blobGrowBuffer(pBlk, p->nNodeSize, &rc);
+        if( rc==SQLITE_OK ){
+          pBlk->a[0] = (char)iLayer;
+          pBlk->n = 1 + sqlite3Fts3PutVarint(&pBlk->a[1], iPtr);
+        }
+      }
+      blobGrowBuffer(pBlk, pBlk->n + nSpace, &rc);
+      blobGrowBuffer(&pNode->key, nTerm, &rc);
+
+      if( rc==SQLITE_OK ){
+        if( pNode->key.n ){
+          pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nPrefix);
+        }
+        pBlk->n += sqlite3Fts3PutVarint(&pBlk->a[pBlk->n], nSuffix);
+        assert( nPrefix+nSuffix<=nTerm );
+        assert( nPrefix>=0 );
+        memcpy(&pBlk->a[pBlk->n], &zTerm[nPrefix], nSuffix);
+        pBlk->n += nSuffix;
+
+        memcpy(pNode->key.a, zTerm, nTerm);
+        pNode->key.n = nTerm;
+      }
+    }else{
+      /* Otherwise, flush the current node of layer iLayer to disk.
+      ** Then allocate a new, empty sibling node. The key will be written
+      ** into the parent of this node. */
+      rc = fts3WriteSegment(p, pNode->iBlock, pNode->block.a, pNode->block.n);
+
+      assert( pNode->block.nAlloc>=p->nNodeSize );
+      pNode->block.a[0] = (char)iLayer;
+      pNode->block.n = 1 + sqlite3Fts3PutVarint(&pNode->block.a[1], iPtr+1);
+
+      iNextPtr = pNode->iBlock;
+      pNode->iBlock++;
+      pNode->key.n = 0;
+    }
+
+    if( rc!=SQLITE_OK || iNextPtr==0 ) return rc;
+    iPtr = iNextPtr;
+  }
+
+  assert( 0 );
+  return 0;
+}
+
+/*
+** Append a term and (optionally) doclist to the FTS segment node currently
+** stored in blob *pNode. The node need not contain any terms, but the
+** header must be written before this function is called.
+**
+** A node header is a single 0x00 byte for a leaf node, or a height varint
+** followed by the left-hand-child varint for an internal node.
+**
+** The term to be appended is passed via arguments zTerm/nTerm. For a
+** leaf node, the doclist is passed as aDoclist/nDoclist. For an internal
+** node, both aDoclist and nDoclist must be passed 0.
+**
+** If the size of the value in blob pPrev is zero, then this is the first
+** term written to the node. Otherwise, pPrev contains a copy of the
+** previous term. Before this function returns, it is updated to contain a
+** copy of zTerm/nTerm.
+**
+** It is assumed that the buffer associated with pNode is already large
+** enough to accommodate the new entry. The buffer associated with pPrev
+** is extended by this function if requrired.
+**
+** If an error (i.e. OOM condition) occurs, an SQLite error code is
+** returned. Otherwise, SQLITE_OK.
+*/
+static int fts3AppendToNode(
+  Blob *pNode,                    /* Current node image to append to */
+  Blob *pPrev,                    /* Buffer containing previous term written */
+  const char *zTerm,              /* New term to write */
+  int nTerm,                      /* Size of zTerm in bytes */
+  const char *aDoclist,           /* Doclist (or NULL) to write */
+  int nDoclist                    /* Size of aDoclist in bytes */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int bFirst = (pPrev->n==0);     /* True if this is the first term written */
+  int nPrefix;                    /* Size of term prefix in bytes */
+  int nSuffix;                    /* Size of term suffix in bytes */
+
+  /* Node must have already been started. There must be a doclist for a
+  ** leaf node, and there must not be a doclist for an internal node.  */
+  assert( pNode->n>0 );
+  assert_fts3_nc( (pNode->a[0]=='\0')==(aDoclist!=0) );
+
+  blobGrowBuffer(pPrev, nTerm, &rc);
+  if( rc!=SQLITE_OK ) return rc;
+  assert( pPrev!=0 );
+  assert( pPrev->a!=0 );
+
+  nPrefix = fts3PrefixCompress(pPrev->a, pPrev->n, zTerm, nTerm);
+  nSuffix = nTerm - nPrefix;
+  if( nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+  memcpy(pPrev->a, zTerm, nTerm);
+  pPrev->n = nTerm;
+
+  if( bFirst==0 ){
+    pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nPrefix);
+  }
+  pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nSuffix);
+  memcpy(&pNode->a[pNode->n], &zTerm[nPrefix], nSuffix);
+  pNode->n += nSuffix;
+
+  if( aDoclist ){
+    pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nDoclist);
+    memcpy(&pNode->a[pNode->n], aDoclist, nDoclist);
+    pNode->n += nDoclist;
+  }
+
+  assert( pNode->n<=pNode->nAlloc );
+
+  return SQLITE_OK;
+}
+
+/*
+** Append the current term and doclist pointed to by cursor pCsr to the
+** appendable b-tree segment opened for writing by pWriter.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise.
+*/
+static int fts3IncrmergeAppend(
+  Fts3Table *p,                   /* Fts3 table handle */
+  IncrmergeWriter *pWriter,       /* Writer object */
+  Fts3MultiSegReader *pCsr        /* Cursor containing term and doclist */
+){
+  const char *zTerm = pCsr->zTerm;
+  int nTerm = pCsr->nTerm;
+  const char *aDoclist = pCsr->aDoclist;
+  int nDoclist = pCsr->nDoclist;
+  int rc = SQLITE_OK;           /* Return code */
+  int nSpace;                   /* Total space in bytes required on leaf */
+  int nPrefix;                  /* Size of prefix shared with previous term */
+  int nSuffix;                  /* Size of suffix (nTerm - nPrefix) */
+  NodeWriter *pLeaf;            /* Object used to write leaf nodes */
+
+  pLeaf = &pWriter->aNodeWriter[0];
+  nPrefix = fts3PrefixCompress(pLeaf->key.a, pLeaf->key.n, zTerm, nTerm);
+  nSuffix = nTerm - nPrefix;
+  if(nSuffix<=0 ) return FTS_CORRUPT_VTAB;
+
+  nSpace  = sqlite3Fts3VarintLen(nPrefix);
+  nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
+  nSpace += sqlite3Fts3VarintLen(nDoclist) + nDoclist;
+
+  /* If the current block is not empty, and if adding this term/doclist
+  ** to the current block would make it larger than Fts3Table.nNodeSize bytes,
+  ** and if there is still room for another leaf page, write this block out to
+  ** the database. */
+  if( pLeaf->block.n>0
+   && (pLeaf->block.n + nSpace)>p->nNodeSize
+   && pLeaf->iBlock < (pWriter->iStart + pWriter->nLeafEst)
+  ){
+    rc = fts3WriteSegment(p, pLeaf->iBlock, pLeaf->block.a, pLeaf->block.n);
+    pWriter->nWork++;
+
+    /* Add the current term to the parent node. The term added to the
+    ** parent must:
+    **
+    **   a) be greater than the largest term on the leaf node just written
+    **      to the database (still available in pLeaf->key), and
+    **
+    **   b) be less than or equal to the term about to be added to the new
+    **      leaf node (zTerm/nTerm).
+    **
+    ** In other words, it must be the prefix of zTerm 1 byte longer than
+    ** the common prefix (if any) of zTerm and pWriter->zTerm.
+    */
+    if( rc==SQLITE_OK ){
+      rc = fts3IncrmergePush(p, pWriter, zTerm, nPrefix+1);
+    }
+
+    /* Advance to the next output block */
+    pLeaf->iBlock++;
+    pLeaf->key.n = 0;
+    pLeaf->block.n = 0;
+
+    nSuffix = nTerm;
+    nSpace  = 1;
+    nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
+    nSpace += sqlite3Fts3VarintLen(nDoclist) + nDoclist;
+  }
+
+  pWriter->nLeafData += nSpace;
+  blobGrowBuffer(&pLeaf->block, pLeaf->block.n + nSpace, &rc);
+  if( rc==SQLITE_OK ){
+    if( pLeaf->block.n==0 ){
+      pLeaf->block.n = 1;
+      pLeaf->block.a[0] = '\0';
+    }
+    rc = fts3AppendToNode(
+        &pLeaf->block, &pLeaf->key, zTerm, nTerm, aDoclist, nDoclist
+    );
+  }
+
+  return rc;
+}
+
+/*
+** This function is called to release all dynamic resources held by the
+** merge-writer object pWriter, and if no error has occurred, to flush
+** all outstanding node buffers held by pWriter to disk.
+**
+** If *pRc is not SQLITE_OK when this function is called, then no attempt
+** is made to write any data to disk. Instead, this function serves only
+** to release outstanding resources.
+**
+** Otherwise, if *pRc is initially SQLITE_OK and an error occurs while
+** flushing buffers to disk, *pRc is set to an SQLite error code before
+** returning.
+*/
+static void fts3IncrmergeRelease(
+  Fts3Table *p,                   /* FTS3 table handle */
+  IncrmergeWriter *pWriter,       /* Merge-writer object */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  int i;                          /* Used to iterate through non-root layers */
+  int iRoot;                      /* Index of root in pWriter->aNodeWriter */
+  NodeWriter *pRoot;              /* NodeWriter for root node */
+  int rc = *pRc;                  /* Error code */
+
+  /* Set iRoot to the index in pWriter->aNodeWriter[] of the output segment
+  ** root node. If the segment fits entirely on a single leaf node, iRoot
+  ** will be set to 0. If the root node is the parent of the leaves, iRoot
+  ** will be 1. And so on.  */
+  for(iRoot=FTS_MAX_APPENDABLE_HEIGHT-1; iRoot>=0; iRoot--){
+    NodeWriter *pNode = &pWriter->aNodeWriter[iRoot];
+    if( pNode->block.n>0 ) break;
+    assert( *pRc || pNode->block.nAlloc==0 );
+    assert( *pRc || pNode->key.nAlloc==0 );
+    sqlite3_free(pNode->block.a);
+    sqlite3_free(pNode->key.a);
+  }
+
+  /* Empty output segment. This is a no-op. */
+  if( iRoot<0 ) return;
+
+  /* The entire output segment fits on a single node. Normally, this means
+  ** the node would be stored as a blob in the "root" column of the %_segdir
+  ** table. However, this is not permitted in this case. The problem is that
+  ** space has already been reserved in the %_segments table, and so the
+  ** start_block and end_block fields of the %_segdir table must be populated.
+  ** And, by design or by accident, released versions of FTS cannot handle
+  ** segments that fit entirely on the root node with start_block!=0.
+  **
+  ** Instead, create a synthetic root node that contains nothing but a
+  ** pointer to the single content node. So that the segment consists of a
+  ** single leaf and a single interior (root) node.
+  **
+  ** Todo: Better might be to defer allocating space in the %_segments
+  ** table until we are sure it is needed.
+  */
+  if( iRoot==0 ){
+    Blob *pBlock = &pWriter->aNodeWriter[1].block;
+    blobGrowBuffer(pBlock, 1 + FTS3_VARINT_MAX, &rc);
+    if( rc==SQLITE_OK ){
+      pBlock->a[0] = 0x01;
+      pBlock->n = 1 + sqlite3Fts3PutVarint(
+          &pBlock->a[1], pWriter->aNodeWriter[0].iBlock
+      );
+    }
+    iRoot = 1;
+  }
+  pRoot = &pWriter->aNodeWriter[iRoot];
+
+  /* Flush all currently outstanding nodes to disk. */
+  for(i=0; i<iRoot; i++){
+    NodeWriter *pNode = &pWriter->aNodeWriter[i];
+    if( pNode->block.n>0 && rc==SQLITE_OK ){
+      rc = fts3WriteSegment(p, pNode->iBlock, pNode->block.a, pNode->block.n);
+    }
+    sqlite3_free(pNode->block.a);
+    sqlite3_free(pNode->key.a);
+  }
+
+  /* Write the %_segdir record. */
+  if( rc==SQLITE_OK ){
+    rc = fts3WriteSegdir(p,
+        pWriter->iAbsLevel+1,               /* level */
+        pWriter->iIdx,                      /* idx */
+        pWriter->iStart,                    /* start_block */
+        pWriter->aNodeWriter[0].iBlock,     /* leaves_end_block */
+        pWriter->iEnd,                      /* end_block */
+        (pWriter->bNoLeafData==0 ? pWriter->nLeafData : 0),   /* end_block */
+        pRoot->block.a, pRoot->block.n      /* root */
+    );
+  }
+  sqlite3_free(pRoot->block.a);
+  sqlite3_free(pRoot->key.a);
+
+  *pRc = rc;
+}
+
+/*
+** Compare the term in buffer zLhs (size in bytes nLhs) with that in
+** zRhs (size in bytes nRhs) using memcmp. If one term is a prefix of
+** the other, it is considered to be smaller than the other.
+**
+** Return -ve if zLhs is smaller than zRhs, 0 if it is equal, or +ve
+** if it is greater.
+*/
+static int fts3TermCmp(
+  const char *zLhs, int nLhs,     /* LHS of comparison */
+  const char *zRhs, int nRhs      /* RHS of comparison */
+){
+  int nCmp = MIN(nLhs, nRhs);
+  int res;
+
+  if( nCmp && ALWAYS(zLhs) && ALWAYS(zRhs) ){
+    res = memcmp(zLhs, zRhs, nCmp);
+  }else{
+    res = 0;
+  }
+  if( res==0 ) res = nLhs - nRhs;
+
+  return res;
+}
+
+
+/*
+** Query to see if the entry in the %_segments table with blockid iEnd is
+** NULL. If no error occurs and the entry is NULL, set *pbRes 1 before
+** returning. Otherwise, set *pbRes to 0.
+**
+** Or, if an error occurs while querying the database, return an SQLite
+** error code. The final value of *pbRes is undefined in this case.
+**
+** This is used to test if a segment is an "appendable" segment. If it
+** is, then a NULL entry has been inserted into the %_segments table
+** with blockid %_segdir.end_block.
+*/
+static int fts3IsAppendable(Fts3Table *p, sqlite3_int64 iEnd, int *pbRes){
+  int bRes = 0;                   /* Result to set *pbRes to */
+  sqlite3_stmt *pCheck = 0;       /* Statement to query database with */
+  int rc;                         /* Return code */
+
+  rc = fts3SqlStmt(p, SQL_SEGMENT_IS_APPENDABLE, &pCheck, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pCheck, 1, iEnd);
+    if( SQLITE_ROW==sqlite3_step(pCheck) ) bRes = 1;
+    rc = sqlite3_reset(pCheck);
+  }
+
+  *pbRes = bRes;
+  return rc;
+}
+
+/*
+** This function is called when initializing an incremental-merge operation.
+** It checks if the existing segment with index value iIdx at absolute level
+** (iAbsLevel+1) can be appended to by the incremental merge. If it can, the
+** merge-writer object *pWriter is initialized to write to it.
+**
+** An existing segment can be appended to by an incremental merge if:
+**
+**   * It was initially created as an appendable segment (with all required
+**     space pre-allocated), and
+**
+**   * The first key read from the input (arguments zKey and nKey) is
+**     greater than the largest key currently stored in the potential
+**     output segment.
+*/
+static int fts3IncrmergeLoad(
+  Fts3Table *p,                   /* Fts3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level of input segments */
+  int iIdx,                       /* Index of candidate output segment */
+  const char *zKey,               /* First key to write */
+  int nKey,                       /* Number of bytes in nKey */
+  IncrmergeWriter *pWriter        /* Populate this object */
+){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pSelect = 0;      /* SELECT to read %_segdir entry */
+
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR, &pSelect, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_int64 iStart = 0;     /* Value of %_segdir.start_block */
+    sqlite3_int64 iLeafEnd = 0;   /* Value of %_segdir.leaves_end_block */
+    sqlite3_int64 iEnd = 0;       /* Value of %_segdir.end_block */
+    const char *aRoot = 0;        /* Pointer to %_segdir.root buffer */
+    int nRoot = 0;                /* Size of aRoot[] in bytes */
+    int rc2;                      /* Return code from sqlite3_reset() */
+    int bAppendable = 0;          /* Set to true if segment is appendable */
+
+    /* Read the %_segdir entry for index iIdx absolute level (iAbsLevel+1) */
+    sqlite3_bind_int64(pSelect, 1, iAbsLevel+1);
+    sqlite3_bind_int(pSelect, 2, iIdx);
+    if( sqlite3_step(pSelect)==SQLITE_ROW ){
+      iStart = sqlite3_column_int64(pSelect, 1);
+      iLeafEnd = sqlite3_column_int64(pSelect, 2);
+      fts3ReadEndBlockField(pSelect, 3, &iEnd, &pWriter->nLeafData);
+      if( pWriter->nLeafData<0 ){
+        pWriter->nLeafData = pWriter->nLeafData * -1;
+      }
+      pWriter->bNoLeafData = (pWriter->nLeafData==0);
+      nRoot = sqlite3_column_bytes(pSelect, 4);
+      aRoot = sqlite3_column_blob(pSelect, 4);
+      if( aRoot==0 ){
+        sqlite3_reset(pSelect);
+        return nRoot ? SQLITE_NOMEM : FTS_CORRUPT_VTAB;
+      }
+    }else{
+      return sqlite3_reset(pSelect);
+    }
+
+    /* Check for the zero-length marker in the %_segments table */
+    rc = fts3IsAppendable(p, iEnd, &bAppendable);
+
+    /* Check that zKey/nKey is larger than the largest key the candidate */
+    if( rc==SQLITE_OK && bAppendable ){
+      char *aLeaf = 0;
+      int nLeaf = 0;
+
+      rc = sqlite3Fts3ReadBlock(p, iLeafEnd, &aLeaf, &nLeaf, 0);
+      if( rc==SQLITE_OK ){
+        NodeReader reader;
+        for(rc = nodeReaderInit(&reader, aLeaf, nLeaf);
+            rc==SQLITE_OK && reader.aNode;
+            rc = nodeReaderNext(&reader)
+        ){
+          assert( reader.aNode );
+        }
+        if( fts3TermCmp(zKey, nKey, reader.term.a, reader.term.n)<=0 ){
+          bAppendable = 0;
+        }
+        nodeReaderRelease(&reader);
+      }
+      sqlite3_free(aLeaf);
+    }
+
+    if( rc==SQLITE_OK && bAppendable ){
+      /* It is possible to append to this segment. Set up the IncrmergeWriter
+      ** object to do so.  */
+      int i;
+      int nHeight = (int)aRoot[0];
+      NodeWriter *pNode;
+      if( nHeight<1 || nHeight>=FTS_MAX_APPENDABLE_HEIGHT ){
+        sqlite3_reset(pSelect);
+        return FTS_CORRUPT_VTAB;
+      }
+
+      pWriter->nLeafEst = (int)((iEnd - iStart) + 1)/FTS_MAX_APPENDABLE_HEIGHT;
+      pWriter->iStart = iStart;
+      pWriter->iEnd = iEnd;
+      pWriter->iAbsLevel = iAbsLevel;
+      pWriter->iIdx = iIdx;
+
+      for(i=nHeight+1; i<FTS_MAX_APPENDABLE_HEIGHT; i++){
+        pWriter->aNodeWriter[i].iBlock = pWriter->iStart + i*pWriter->nLeafEst;
+      }
+
+      pNode = &pWriter->aNodeWriter[nHeight];
+      pNode->iBlock = pWriter->iStart + pWriter->nLeafEst*nHeight;
+      blobGrowBuffer(&pNode->block,
+          MAX(nRoot, p->nNodeSize)+FTS3_NODE_PADDING, &rc
+      );
+      if( rc==SQLITE_OK ){
+        memcpy(pNode->block.a, aRoot, nRoot);
+        pNode->block.n = nRoot;
+        memset(&pNode->block.a[nRoot], 0, FTS3_NODE_PADDING);
+      }
+
+      for(i=nHeight; i>=0 && rc==SQLITE_OK; i--){
+        NodeReader reader;
+        memset(&reader, 0, sizeof(reader));
+        pNode = &pWriter->aNodeWriter[i];
+
+        if( pNode->block.a){
+          rc = nodeReaderInit(&reader, pNode->block.a, pNode->block.n);
+          while( reader.aNode && rc==SQLITE_OK ) rc = nodeReaderNext(&reader);
+          blobGrowBuffer(&pNode->key, reader.term.n, &rc);
+          if( rc==SQLITE_OK ){
+            assert_fts3_nc( reader.term.n>0 || reader.aNode==0 );
+            if( reader.term.n>0 ){
+              memcpy(pNode->key.a, reader.term.a, reader.term.n);
+            }
+            pNode->key.n = reader.term.n;
+            if( i>0 ){
+              char *aBlock = 0;
+              int nBlock = 0;
+              pNode = &pWriter->aNodeWriter[i-1];
+              pNode->iBlock = reader.iChild;
+              rc = sqlite3Fts3ReadBlock(p, reader.iChild, &aBlock, &nBlock,0);
+              blobGrowBuffer(&pNode->block,
+                  MAX(nBlock, p->nNodeSize)+FTS3_NODE_PADDING, &rc
+              );
+              if( rc==SQLITE_OK ){
+                memcpy(pNode->block.a, aBlock, nBlock);
+                pNode->block.n = nBlock;
+                memset(&pNode->block.a[nBlock], 0, FTS3_NODE_PADDING);
+              }
+              sqlite3_free(aBlock);
+            }
+          }
+        }
+        nodeReaderRelease(&reader);
+      }
+    }
+
+    rc2 = sqlite3_reset(pSelect);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  return rc;
+}
+
+/*
+** Determine the largest segment index value that exists within absolute
+** level iAbsLevel+1. If no error occurs, set *piIdx to this value plus
+** one before returning SQLITE_OK. Or, if there are no segments at all
+** within level iAbsLevel, set *piIdx to zero.
+**
+** If an error occurs, return an SQLite error code. The final value of
+** *piIdx is undefined in this case.
+*/
+static int fts3IncrmergeOutputIdx(
+  Fts3Table *p,                   /* FTS Table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute index of input segments */
+  int *piIdx                      /* OUT: Next free index at iAbsLevel+1 */
+){
+  int rc;
+  sqlite3_stmt *pOutputIdx = 0;   /* SQL used to find output index */
+
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pOutputIdx, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pOutputIdx, 1, iAbsLevel+1);
+    sqlite3_step(pOutputIdx);
+    *piIdx = sqlite3_column_int(pOutputIdx, 0);
+    rc = sqlite3_reset(pOutputIdx);
+  }
+
+  return rc;
+}
+
+/*
+** Allocate an appendable output segment on absolute level iAbsLevel+1
+** with idx value iIdx.
+**
+** In the %_segdir table, a segment is defined by the values in three
+** columns:
+**
+**     start_block
+**     leaves_end_block
+**     end_block
+**
+** When an appendable segment is allocated, it is estimated that the
+** maximum number of leaf blocks that may be required is the sum of the
+** number of leaf blocks consumed by the input segments, plus the number
+** of input segments, multiplied by two. This value is stored in stack
+** variable nLeafEst.
+**
+** A total of 16*nLeafEst blocks are allocated when an appendable segment
+** is created ((1 + end_block - start_block)==16*nLeafEst). The contiguous
+** array of leaf nodes starts at the first block allocated. The array
+** of interior nodes that are parents of the leaf nodes start at block
+** (start_block + (1 + end_block - start_block) / 16). And so on.
+**
+** In the actual code below, the value "16" is replaced with the
+** pre-processor macro FTS_MAX_APPENDABLE_HEIGHT.
+*/
+static int fts3IncrmergeWriter(
+  Fts3Table *p,                   /* Fts3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level of input segments */
+  int iIdx,                       /* Index of new output segment */
+  Fts3MultiSegReader *pCsr,       /* Cursor that data will be read from */
+  IncrmergeWriter *pWriter        /* Populate this object */
+){
+  int rc;                         /* Return Code */
+  int i;                          /* Iterator variable */
+  int nLeafEst = 0;               /* Blocks allocated for leaf nodes */
+  sqlite3_stmt *pLeafEst = 0;     /* SQL used to determine nLeafEst */
+  sqlite3_stmt *pFirstBlock = 0;  /* SQL used to determine first block */
+
+  /* Calculate nLeafEst. */
+  rc = fts3SqlStmt(p, SQL_MAX_LEAF_NODE_ESTIMATE, &pLeafEst, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pLeafEst, 1, iAbsLevel);
+    sqlite3_bind_int64(pLeafEst, 2, pCsr->nSegment);
+    if( SQLITE_ROW==sqlite3_step(pLeafEst) ){
+      nLeafEst = sqlite3_column_int(pLeafEst, 0);
+    }
+    rc = sqlite3_reset(pLeafEst);
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Calculate the first block to use in the output segment */
+  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENTS_ID, &pFirstBlock, 0);
+  if( rc==SQLITE_OK ){
+    if( SQLITE_ROW==sqlite3_step(pFirstBlock) ){
+      pWriter->iStart = sqlite3_column_int64(pFirstBlock, 0);
+      pWriter->iEnd = pWriter->iStart - 1;
+      pWriter->iEnd += nLeafEst * FTS_MAX_APPENDABLE_HEIGHT;
+    }
+    rc = sqlite3_reset(pFirstBlock);
+  }
+  if( rc!=SQLITE_OK ) return rc;
+
+  /* Insert the marker in the %_segments table to make sure nobody tries
+  ** to steal the space just allocated. This is also used to identify
+  ** appendable segments.  */
+  rc = fts3WriteSegment(p, pWriter->iEnd, 0, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  pWriter->iAbsLevel = iAbsLevel;
+  pWriter->nLeafEst = nLeafEst;
+  pWriter->iIdx = iIdx;
+
+  /* Set up the array of NodeWriter objects */
+  for(i=0; i<FTS_MAX_APPENDABLE_HEIGHT; i++){
+    pWriter->aNodeWriter[i].iBlock = pWriter->iStart + i*pWriter->nLeafEst;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Remove an entry from the %_segdir table. This involves running the
+** following two statements:
+**
+**   DELETE FROM %_segdir WHERE level = :iAbsLevel AND idx = :iIdx
+**   UPDATE %_segdir SET idx = idx - 1 WHERE level = :iAbsLevel AND idx > :iIdx
+**
+** The DELETE statement removes the specific %_segdir level. The UPDATE
+** statement ensures that the remaining segments have contiguously allocated
+** idx values.
+*/
+static int fts3RemoveSegdirEntry(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level to delete from */
+  int iIdx                        /* Index of %_segdir entry to delete */
+){
+  int rc;                         /* Return code */
+  sqlite3_stmt *pDelete = 0;      /* DELETE statement */
+
+  rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_ENTRY, &pDelete, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pDelete, 1, iAbsLevel);
+    sqlite3_bind_int(pDelete, 2, iIdx);
+    sqlite3_step(pDelete);
+    rc = sqlite3_reset(pDelete);
+  }
+
+  return rc;
+}
+
+/*
+** One or more segments have just been removed from absolute level iAbsLevel.
+** Update the 'idx' values of the remaining segments in the level so that
+** the idx values are a contiguous sequence starting from 0.
+*/
+static int fts3RepackSegdirLevel(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel         /* Absolute level to repack */
+){
+  int rc;                         /* Return code */
+  int *aIdx = 0;                  /* Array of remaining idx values */
+  int nIdx = 0;                   /* Valid entries in aIdx[] */
+  int nAlloc = 0;                 /* Allocated size of aIdx[] */
+  int i;                          /* Iterator variable */
+  sqlite3_stmt *pSelect = 0;      /* Select statement to read idx values */
+  sqlite3_stmt *pUpdate = 0;      /* Update statement to modify idx values */
+
+  rc = fts3SqlStmt(p, SQL_SELECT_INDEXES, &pSelect, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int64(pSelect, 1, iAbsLevel);
+    while( SQLITE_ROW==sqlite3_step(pSelect) ){
+      if( nIdx>=nAlloc ){
+        int *aNew;
+        nAlloc += 16;
+        aNew = sqlite3_realloc64(aIdx, nAlloc*sizeof(int));
+        if( !aNew ){
+          rc = SQLITE_NOMEM;
+          break;
+        }
+        aIdx = aNew;
+      }
+      aIdx[nIdx++] = sqlite3_column_int(pSelect, 0);
+    }
+    rc2 = sqlite3_reset(pSelect);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts3SqlStmt(p, SQL_SHIFT_SEGDIR_ENTRY, &pUpdate, 0);
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pUpdate, 2, iAbsLevel);
+  }
+
+  assert( p->bIgnoreSavepoint==0 );
+  p->bIgnoreSavepoint = 1;
+  for(i=0; rc==SQLITE_OK && i<nIdx; i++){
+    if( aIdx[i]!=i ){
+      sqlite3_bind_int(pUpdate, 3, aIdx[i]);
+      sqlite3_bind_int(pUpdate, 1, i);
+      sqlite3_step(pUpdate);
+      rc = sqlite3_reset(pUpdate);
+    }
+  }
+  p->bIgnoreSavepoint = 0;
+
+  sqlite3_free(aIdx);
+  return rc;
+}
+
+static void fts3StartNode(Blob *pNode, int iHeight, sqlite3_int64 iChild){
+  pNode->a[0] = (char)iHeight;
+  if( iChild ){
+    assert( pNode->nAlloc>=1+sqlite3Fts3VarintLen(iChild) );
+    pNode->n = 1 + sqlite3Fts3PutVarint(&pNode->a[1], iChild);
+  }else{
+    assert( pNode->nAlloc>=1 );
+    pNode->n = 1;
+  }
+}
+
+/*
+** The first two arguments are a pointer to and the size of a segment b-tree
+** node. The node may be a leaf or an internal node.
+**
+** This function creates a new node image in blob object *pNew by copying
+** all terms that are greater than or equal to zTerm/nTerm (for leaf nodes)
+** or greater than zTerm/nTerm (for internal nodes) from aNode/nNode.
+*/
+static int fts3TruncateNode(
+  const char *aNode,              /* Current node image */
+  int nNode,                      /* Size of aNode in bytes */
+  Blob *pNew,                     /* OUT: Write new node image here */
+  const char *zTerm,              /* Omit all terms smaller than this */
+  int nTerm,                      /* Size of zTerm in bytes */
+  sqlite3_int64 *piBlock          /* OUT: Block number in next layer down */
+){
+  NodeReader reader;              /* Reader object */
+  Blob prev = {0, 0, 0};          /* Previous term written to new node */
+  int rc = SQLITE_OK;             /* Return code */
+  int bLeaf;                       /* True for a leaf node */
+
+  if( nNode<1 ) return FTS_CORRUPT_VTAB;
+  bLeaf = aNode[0]=='\0';
+
+  /* Allocate required output space */
+  blobGrowBuffer(pNew, nNode, &rc);
+  if( rc!=SQLITE_OK ) return rc;
+  pNew->n = 0;
+
+  /* Populate new node buffer */
+  for(rc = nodeReaderInit(&reader, aNode, nNode);
+      rc==SQLITE_OK && reader.aNode;
+      rc = nodeReaderNext(&reader)
+  ){
+    if( pNew->n==0 ){
+      int res = fts3TermCmp(reader.term.a, reader.term.n, zTerm, nTerm);
+      if( res<0 || (bLeaf==0 && res==0) ) continue;
+      fts3StartNode(pNew, (int)aNode[0], reader.iChild);
+      *piBlock = reader.iChild;
+    }
+    rc = fts3AppendToNode(
+        pNew, &prev, reader.term.a, reader.term.n,
+        reader.aDoclist, reader.nDoclist
+    );
+    if( rc!=SQLITE_OK ) break;
+  }
+  if( pNew->n==0 ){
+    fts3StartNode(pNew, (int)aNode[0], reader.iChild);
+    *piBlock = reader.iChild;
+  }
+  assert( pNew->n<=pNew->nAlloc );
+
+  nodeReaderRelease(&reader);
+  sqlite3_free(prev.a);
+  return rc;
+}
+
+/*
+** Remove all terms smaller than zTerm/nTerm from segment iIdx in absolute
+** level iAbsLevel. This may involve deleting entries from the %_segments
+** table, and modifying existing entries in both the %_segments and %_segdir
+** tables.
+**
+** SQLITE_OK is returned if the segment is updated successfully. Or an
+** SQLite error code otherwise.
+*/
+static int fts3TruncateSegment(
+  Fts3Table *p,                   /* FTS3 table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level of segment to modify */
+  int iIdx,                       /* Index within level of segment to modify */
+  const char *zTerm,              /* Remove terms smaller than this */
+  int nTerm                      /* Number of bytes in buffer zTerm */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Blob root = {0,0,0};            /* New root page image */
+  Blob block = {0,0,0};           /* Buffer used for any other block */
+  sqlite3_int64 iBlock = 0;       /* Block id */
+  sqlite3_int64 iNewStart = 0;    /* New value for iStartBlock */
+  sqlite3_int64 iOldStart = 0;    /* Old value for iStartBlock */
+  sqlite3_stmt *pFetch = 0;       /* Statement used to fetch segdir */
+
+  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR, &pFetch, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;                      /* sqlite3_reset() return code */
+    sqlite3_bind_int64(pFetch, 1, iAbsLevel);
+    sqlite3_bind_int(pFetch, 2, iIdx);
+    if( SQLITE_ROW==sqlite3_step(pFetch) ){
+      const char *aRoot = sqlite3_column_blob(pFetch, 4);
+      int nRoot = sqlite3_column_bytes(pFetch, 4);
+      iOldStart = sqlite3_column_int64(pFetch, 1);
+      rc = fts3TruncateNode(aRoot, nRoot, &root, zTerm, nTerm, &iBlock);
+    }
+    rc2 = sqlite3_reset(pFetch);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  while( rc==SQLITE_OK && iBlock ){
+    char *aBlock = 0;
+    int nBlock = 0;
+    iNewStart = iBlock;
+
+    rc = sqlite3Fts3ReadBlock(p, iBlock, &aBlock, &nBlock, 0);
+    if( rc==SQLITE_OK ){
+      rc = fts3TruncateNode(aBlock, nBlock, &block, zTerm, nTerm, &iBlock);
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3WriteSegment(p, iNewStart, block.a, block.n);
+    }
+    sqlite3_free(aBlock);
+  }
+
+  /* Variable iNewStart now contains the first valid leaf node. */
+  if( rc==SQLITE_OK && iNewStart ){
+    sqlite3_stmt *pDel = 0;
+    rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDel, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDel, 1, iOldStart);
+      sqlite3_bind_int64(pDel, 2, iNewStart-1);
+      sqlite3_step(pDel);
+      rc = sqlite3_reset(pDel);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sqlite3_stmt *pChomp = 0;
+    rc = fts3SqlStmt(p, SQL_CHOMP_SEGDIR, &pChomp, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pChomp, 1, iNewStart);
+      sqlite3_bind_blob(pChomp, 2, root.a, root.n, SQLITE_STATIC);
+      sqlite3_bind_int64(pChomp, 3, iAbsLevel);
+      sqlite3_bind_int(pChomp, 4, iIdx);
+      sqlite3_step(pChomp);
+      rc = sqlite3_reset(pChomp);
+      sqlite3_bind_null(pChomp, 2);
+    }
+  }
+
+  sqlite3_free(root.a);
+  sqlite3_free(block.a);
+  return rc;
+}
+
+/*
+** This function is called after an incrmental-merge operation has run to
+** merge (or partially merge) two or more segments from absolute level
+** iAbsLevel.
+**
+** Each input segment is either removed from the db completely (if all of
+** its data was copied to the output segment by the incrmerge operation)
+** or modified in place so that it no longer contains those entries that
+** have been duplicated in the output segment.
+*/
+static int fts3IncrmergeChomp(
+  Fts3Table *p,                   /* FTS table handle */
+  sqlite3_int64 iAbsLevel,        /* Absolute level containing segments */
+  Fts3MultiSegReader *pCsr,       /* Chomp all segments opened by this cursor */
+  int *pnRem                      /* Number of segments not deleted */
+){
+  int i;
+  int nRem = 0;
+  int rc = SQLITE_OK;
+
+  for(i=pCsr->nSegment-1; i>=0 && rc==SQLITE_OK; i--){
+    Fts3SegReader *pSeg = 0;
+    int j;
+
+    /* Find the Fts3SegReader object with Fts3SegReader.iIdx==i. It is hiding
+    ** somewhere in the pCsr->apSegment[] array.  */
+    for(j=0; ALWAYS(j<pCsr->nSegment); j++){
+      pSeg = pCsr->apSegment[j];
+      if( pSeg->iIdx==i ) break;
+    }
+    assert( j<pCsr->nSegment && pSeg->iIdx==i );
+
+    if( pSeg->aNode==0 ){
+      /* Seg-reader is at EOF. Remove the entire input segment. */
+      rc = fts3DeleteSegment(p, pSeg);
+      if( rc==SQLITE_OK ){
+        rc = fts3RemoveSegdirEntry(p, iAbsLevel, pSeg->iIdx);
+      }
+      *pnRem = 0;
+    }else{
+      /* The incremental merge did not copy all the data from this
+      ** segment to the upper level. The segment is modified in place
+      ** so that it contains no keys smaller than zTerm/nTerm. */
+      const char *zTerm = pSeg->zTerm;
+      int nTerm = pSeg->nTerm;
+      rc = fts3TruncateSegment(p, iAbsLevel, pSeg->iIdx, zTerm, nTerm);
+      nRem++;
+    }
+  }
+
+  if( rc==SQLITE_OK && nRem!=pCsr->nSegment ){
+    rc = fts3RepackSegdirLevel(p, iAbsLevel);
+  }
+
+  *pnRem = nRem;
+  return rc;
+}
+
+/*
+** Store an incr-merge hint in the database.
+*/
+static int fts3IncrmergeHintStore(Fts3Table *p, Blob *pHint){
+  sqlite3_stmt *pReplace = 0;
+  int rc;                         /* Return code */
+
+  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pReplace, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int(pReplace, 1, FTS_STAT_INCRMERGEHINT);
+    sqlite3_bind_blob(pReplace, 2, pHint->a, pHint->n, SQLITE_STATIC);
+    sqlite3_step(pReplace);
+    rc = sqlite3_reset(pReplace);
+    sqlite3_bind_null(pReplace, 2);
+  }
+
+  return rc;
+}
+
+/*
+** Load an incr-merge hint from the database. The incr-merge hint, if one
+** exists, is stored in the rowid==1 row of the %_stat table.
+**
+** If successful, populate blob *pHint with the value read from the %_stat
+** table and return SQLITE_OK. Otherwise, if an error occurs, return an
+** SQLite error code.
+*/
+static int fts3IncrmergeHintLoad(Fts3Table *p, Blob *pHint){
+  sqlite3_stmt *pSelect = 0;
+  int rc;
+
+  pHint->n = 0;
+  rc = fts3SqlStmt(p, SQL_SELECT_STAT, &pSelect, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int(pSelect, 1, FTS_STAT_INCRMERGEHINT);
+    if( SQLITE_ROW==sqlite3_step(pSelect) ){
+      const char *aHint = sqlite3_column_blob(pSelect, 0);
+      int nHint = sqlite3_column_bytes(pSelect, 0);
+      if( aHint ){
+        blobGrowBuffer(pHint, nHint, &rc);
+        if( rc==SQLITE_OK ){
+          if( ALWAYS(pHint->a!=0) ) memcpy(pHint->a, aHint, nHint);
+          pHint->n = nHint;
+        }
+      }
+    }
+    rc2 = sqlite3_reset(pSelect);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  return rc;
+}
+
+/*
+** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
+** Otherwise, append an entry to the hint stored in blob *pHint. Each entry
+** consists of two varints, the absolute level number of the input segments
+** and the number of input segments.
+**
+** If successful, leave *pRc set to SQLITE_OK and return. If an error occurs,
+** set *pRc to an SQLite error code before returning.
+*/
+static void fts3IncrmergeHintPush(
+  Blob *pHint,                    /* Hint blob to append to */
+  i64 iAbsLevel,                  /* First varint to store in hint */
+  int nInput,                     /* Second varint to store in hint */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  blobGrowBuffer(pHint, pHint->n + 2*FTS3_VARINT_MAX, pRc);
+  if( *pRc==SQLITE_OK ){
+    pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], iAbsLevel);
+    pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], (i64)nInput);
+  }
+}
+
+/*
+** Read the last entry (most recently pushed) from the hint blob *pHint
+** and then remove the entry. Write the two values read to *piAbsLevel and
+** *pnInput before returning.
+**
+** If no error occurs, return SQLITE_OK. If the hint blob in *pHint does
+** not contain at least two valid varints, return SQLITE_CORRUPT_VTAB.
+*/
+static int fts3IncrmergeHintPop(Blob *pHint, i64 *piAbsLevel, int *pnInput){
+  const int nHint = pHint->n;
+  int i;
+
+  i = pHint->n-1;
+  if( (pHint->a[i] & 0x80) ) return FTS_CORRUPT_VTAB;
+  while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
+  if( i==0 ) return FTS_CORRUPT_VTAB;
+  i--;
+  while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
+
+  pHint->n = i;
+  i += sqlite3Fts3GetVarint(&pHint->a[i], piAbsLevel);
+  i += fts3GetVarint32(&pHint->a[i], pnInput);
+  assert( i<=nHint );
+  if( i!=nHint ) return FTS_CORRUPT_VTAB;
+
+  return SQLITE_OK;
+}
+
+
+/*
+** Attempt an incremental merge that writes nMerge leaf blocks.
+**
+** Incremental merges happen nMin segments at a time. The segments
+** to be merged are the nMin oldest segments (the ones with the smallest
+** values for the _segdir.idx field) in the highest level that contains
+** at least nMin segments. Multiple merges might occur in an attempt to
+** write the quota of nMerge leaf blocks.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Incrmerge(Fts3Table *p, int nMerge, int nMin){
+  int rc;                         /* Return code */
+  int nRem = nMerge;              /* Number of leaf pages yet to  be written */
+  Fts3MultiSegReader *pCsr;       /* Cursor used to read input data */
+  Fts3SegFilter *pFilter;         /* Filter used with cursor pCsr */
+  IncrmergeWriter *pWriter;       /* Writer object */
+  int nSeg = 0;                   /* Number of input segments */
+  sqlite3_int64 iAbsLevel = 0;    /* Absolute level number to work on */
+  Blob hint = {0, 0, 0};          /* Hint read from %_stat table */
+  int bDirtyHint = 0;             /* True if blob 'hint' has been modified */
+
+  /* Allocate space for the cursor, filter and writer objects */
+  const int nAlloc = sizeof(*pCsr) + sizeof(*pFilter) + sizeof(*pWriter);
+  pWriter = (IncrmergeWriter *)sqlite3_malloc64(nAlloc);
+  if( !pWriter ) return SQLITE_NOMEM;
+  pFilter = (Fts3SegFilter *)&pWriter[1];
+  pCsr = (Fts3MultiSegReader *)&pFilter[1];
+
+  rc = fts3IncrmergeHintLoad(p, &hint);
+  while( rc==SQLITE_OK && nRem>0 ){
+    const i64 nMod = FTS3_SEGDIR_MAXLEVEL * p->nIndex;
+    sqlite3_stmt *pFindLevel = 0; /* SQL used to determine iAbsLevel */
+    int bUseHint = 0;             /* True if attempting to append */
+    int iIdx = 0;                 /* Largest idx in level (iAbsLevel+1) */
+
+    /* Search the %_segdir table for the absolute level with the smallest
+    ** relative level number that contains at least nMin segments, if any.
+    ** If one is found, set iAbsLevel to the absolute level number and
+    ** nSeg to nMin. If no level with at least nMin segments can be found,
+    ** set nSeg to -1.
+    */
+    rc = fts3SqlStmt(p, SQL_FIND_MERGE_LEVEL, &pFindLevel, 0);
+    sqlite3_bind_int(pFindLevel, 1, MAX(2, nMin));
+    if( sqlite3_step(pFindLevel)==SQLITE_ROW ){
+      iAbsLevel = sqlite3_column_int64(pFindLevel, 0);
+      nSeg = sqlite3_column_int(pFindLevel, 1);
+      assert( nSeg>=2 );
+    }else{
+      nSeg = -1;
+    }
+    rc = sqlite3_reset(pFindLevel);
+
+    /* If the hint read from the %_stat table is not empty, check if the
+    ** last entry in it specifies a relative level smaller than or equal
+    ** to the level identified by the block above (if any). If so, this
+    ** iteration of the loop will work on merging at the hinted level.
+    */
+    if( rc==SQLITE_OK && hint.n ){
+      int nHint = hint.n;
+      sqlite3_int64 iHintAbsLevel = 0;      /* Hint level */
+      int nHintSeg = 0;                     /* Hint number of segments */
+
+      rc = fts3IncrmergeHintPop(&hint, &iHintAbsLevel, &nHintSeg);
+      if( nSeg<0 || (iAbsLevel % nMod) >= (iHintAbsLevel % nMod) ){
+        /* Based on the scan in the block above, it is known that there
+        ** are no levels with a relative level smaller than that of
+        ** iAbsLevel with more than nSeg segments, or if nSeg is -1,
+        ** no levels with more than nMin segments. Use this to limit the
+        ** value of nHintSeg to avoid a large memory allocation in case the
+        ** merge-hint is corrupt*/
+        iAbsLevel = iHintAbsLevel;
+        nSeg = MIN(MAX(nMin,nSeg), nHintSeg);
+        bUseHint = 1;
+        bDirtyHint = 1;
+      }else{
+        /* This undoes the effect of the HintPop() above - so that no entry
+        ** is removed from the hint blob.  */
+        hint.n = nHint;
+      }
+    }
+
+    /* If nSeg is less that zero, then there is no level with at least
+    ** nMin segments and no hint in the %_stat table. No work to do.
+    ** Exit early in this case.  */
+    if( nSeg<=0 ) break;
+
+    assert( nMod<=0x7FFFFFFF );
+    if( iAbsLevel<0 || iAbsLevel>(nMod<<32) ){
+      rc = FTS_CORRUPT_VTAB;
+      break;
+    }
+
+    /* Open a cursor to iterate through the contents of the oldest nSeg
+    ** indexes of absolute level iAbsLevel. If this cursor is opened using
+    ** the 'hint' parameters, it is possible that there are less than nSeg
+    ** segments available in level iAbsLevel. In this case, no work is
+    ** done on iAbsLevel - fall through to the next iteration of the loop
+    ** to start work on some other level.  */
+    memset(pWriter, 0, nAlloc);
+    pFilter->flags = FTS3_SEGMENT_REQUIRE_POS;
+
+    if( rc==SQLITE_OK ){
+      rc = fts3IncrmergeOutputIdx(p, iAbsLevel, &iIdx);
+      assert( bUseHint==1 || bUseHint==0 );
+      if( iIdx==0 || (bUseHint && iIdx==1) ){
+        int bIgnore = 0;
+        rc = fts3SegmentIsMaxLevel(p, iAbsLevel+1, &bIgnore);
+        if( bIgnore ){
+          pFilter->flags |= FTS3_SEGMENT_IGNORE_EMPTY;
+        }
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = fts3IncrmergeCsr(p, iAbsLevel, nSeg, pCsr);
+    }
+    if( SQLITE_OK==rc && pCsr->nSegment==nSeg
+     && SQLITE_OK==(rc = sqlite3Fts3SegReaderStart(p, pCsr, pFilter))
+    ){
+      int bEmpty = 0;
+      rc = sqlite3Fts3SegReaderStep(p, pCsr);
+      if( rc==SQLITE_OK ){
+        bEmpty = 1;
+      }else if( rc!=SQLITE_ROW ){
+        sqlite3Fts3SegReaderFinish(pCsr);
+        break;
+      }
+      if( bUseHint && iIdx>0 ){
+        const char *zKey = pCsr->zTerm;
+        int nKey = pCsr->nTerm;
+        rc = fts3IncrmergeLoad(p, iAbsLevel, iIdx-1, zKey, nKey, pWriter);
+      }else{
+        rc = fts3IncrmergeWriter(p, iAbsLevel, iIdx, pCsr, pWriter);
+      }
+
+      if( rc==SQLITE_OK && pWriter->nLeafEst ){
+        fts3LogMerge(nSeg, iAbsLevel);
+        if( bEmpty==0 ){
+          do {
+            rc = fts3IncrmergeAppend(p, pWriter, pCsr);
+            if( rc==SQLITE_OK ) rc = sqlite3Fts3SegReaderStep(p, pCsr);
+            if( pWriter->nWork>=nRem && rc==SQLITE_ROW ) rc = SQLITE_OK;
+          }while( rc==SQLITE_ROW );
+        }
+
+        /* Update or delete the input segments */
+        if( rc==SQLITE_OK ){
+          nRem -= (1 + pWriter->nWork);
+          rc = fts3IncrmergeChomp(p, iAbsLevel, pCsr, &nSeg);
+          if( nSeg!=0 ){
+            bDirtyHint = 1;
+            fts3IncrmergeHintPush(&hint, iAbsLevel, nSeg, &rc);
+          }
+        }
+      }
+
+      if( nSeg!=0 ){
+        pWriter->nLeafData = pWriter->nLeafData * -1;
+      }
+      fts3IncrmergeRelease(p, pWriter, &rc);
+      if( nSeg==0 && pWriter->bNoLeafData==0 ){
+        fts3PromoteSegments(p, iAbsLevel+1, pWriter->nLeafData);
+      }
+    }
+
+    sqlite3Fts3SegReaderFinish(pCsr);
+  }
+
+  /* Write the hint values into the %_stat table for the next incr-merger */
+  if( bDirtyHint && rc==SQLITE_OK ){
+    rc = fts3IncrmergeHintStore(p, &hint);
+  }
+
+  sqlite3_free(pWriter);
+  sqlite3_free(hint.a);
+  return rc;
+}
+
+/*
+** Convert the text beginning at *pz into an integer and return
+** its value.  Advance *pz to point to the first character past
+** the integer.
+**
+** This function used for parameters to merge= and incrmerge=
+** commands.
+*/
+static int fts3Getint(const char **pz){
+  const char *z = *pz;
+  int i = 0;
+  while( (*z)>='0' && (*z)<='9' && i<214748363 ) i = 10*i + *(z++) - '0';
+  *pz = z;
+  return i;
+}
+
+/*
+** Process statements of the form:
+**
+**    INSERT INTO table(table) VALUES('merge=A,B');
+**
+** A and B are integers that decode to be the number of leaf pages
+** written for the merge, and the minimum number of segments on a level
+** before it will be selected for a merge, respectively.
+*/
+static int fts3DoIncrmerge(
+  Fts3Table *p,                   /* FTS3 table handle */
+  const char *zParam              /* Nul-terminated string containing "A,B" */
+){
+  int rc;
+  int nMin = (MergeCount(p) / 2);
+  int nMerge = 0;
+  const char *z = zParam;
+
+  /* Read the first integer value */
+  nMerge = fts3Getint(&z);
+
+  /* If the first integer value is followed by a ',',  read the second
+  ** integer value. */
+  if( z[0]==',' && z[1]!='\0' ){
+    z++;
+    nMin = fts3Getint(&z);
+  }
+
+  if( z[0]!='\0' || nMin<2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    rc = SQLITE_OK;
+    if( !p->bHasStat ){
+      assert( p->bFts4==0 );
+      sqlite3Fts3CreateStatTable(&rc, p);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts3Incrmerge(p, nMerge, nMin);
+    }
+    sqlite3Fts3SegmentsClose(p);
+  }
+  return rc;
+}
+
+/*
+** Process statements of the form:
+**
+**    INSERT INTO table(table) VALUES('automerge=X');
+**
+** where X is an integer.  X==0 means to turn automerge off.  X!=0 means
+** turn it on.  The setting is persistent.
+*/
+static int fts3DoAutoincrmerge(
+  Fts3Table *p,                   /* FTS3 table handle */
+  const char *zParam              /* Nul-terminated string containing boolean */
+){
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pStmt = 0;
+  p->nAutoincrmerge = fts3Getint(&zParam);
+  if( p->nAutoincrmerge==1 || p->nAutoincrmerge>MergeCount(p) ){
+    p->nAutoincrmerge = 8;
+  }
+  if( !p->bHasStat ){
+    assert( p->bFts4==0 );
+    sqlite3Fts3CreateStatTable(&rc, p);
+    if( rc ) return rc;
+  }
+  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pStmt, 0);
+  if( rc ) return rc;
+  sqlite3_bind_int(pStmt, 1, FTS_STAT_AUTOINCRMERGE);
+  sqlite3_bind_int(pStmt, 2, p->nAutoincrmerge);
+  sqlite3_step(pStmt);
+  rc = sqlite3_reset(pStmt);
+  return rc;
+}
+
+/*
+** Return a 64-bit checksum for the FTS index entry specified by the
+** arguments to this function.
+*/
+static u64 fts3ChecksumEntry(
+  const char *zTerm,              /* Pointer to buffer containing term */
+  int nTerm,                      /* Size of zTerm in bytes */
+  int iLangid,                    /* Language id for current row */
+  int iIndex,                     /* Index (0..Fts3Table.nIndex-1) */
+  i64 iDocid,                     /* Docid for current row. */
+  int iCol,                       /* Column number */
+  int iPos                        /* Position */
+){
+  int i;
+  u64 ret = (u64)iDocid;
+
+  ret += (ret<<3) + iLangid;
+  ret += (ret<<3) + iIndex;
+  ret += (ret<<3) + iCol;
+  ret += (ret<<3) + iPos;
+  for(i=0; i<nTerm; i++) ret += (ret<<3) + zTerm[i];
+
+  return ret;
+}
+
+/*
+** Return a checksum of all entries in the FTS index that correspond to
+** language id iLangid. The checksum is calculated by XORing the checksums
+** of each individual entry (see fts3ChecksumEntry()) together.
+**
+** If successful, the checksum value is returned and *pRc set to SQLITE_OK.
+** Otherwise, if an error occurs, *pRc is set to an SQLite error code. The
+** return value is undefined in this case.
+*/
+static u64 fts3ChecksumIndex(
+  Fts3Table *p,                   /* FTS3 table handle */
+  int iLangid,                    /* Language id to return cksum for */
+  int iIndex,                     /* Index to cksum (0..p->nIndex-1) */
+  int *pRc                        /* OUT: Return code */
+){
+  Fts3SegFilter filter;
+  Fts3MultiSegReader csr;
+  int rc;
+  u64 cksum = 0;
+
+  if( *pRc ) return 0;
+
+  memset(&filter, 0, sizeof(filter));
+  memset(&csr, 0, sizeof(csr));
+  filter.flags =  FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
+  filter.flags |= FTS3_SEGMENT_SCAN;
+
+  rc = sqlite3Fts3SegReaderCursor(
+      p, iLangid, iIndex, FTS3_SEGCURSOR_ALL, 0, 0, 0, 1,&csr
+  );
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
+  }
+
+  if( rc==SQLITE_OK ){
+    while( SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, &csr)) ){
+      char *pCsr = csr.aDoclist;
+      char *pEnd = &pCsr[csr.nDoclist];
+
+      i64 iDocid = 0;
+      i64 iCol = 0;
+      u64 iPos = 0;
+
+      pCsr += sqlite3Fts3GetVarint(pCsr, &iDocid);
+      while( pCsr<pEnd ){
+        u64 iVal = 0;
+        pCsr += sqlite3Fts3GetVarintU(pCsr, &iVal);
+        if( pCsr<pEnd ){
+          if( iVal==0 || iVal==1 ){
+            iCol = 0;
+            iPos = 0;
+            if( iVal ){
+              pCsr += sqlite3Fts3GetVarint(pCsr, &iCol);
+            }else{
+              pCsr += sqlite3Fts3GetVarintU(pCsr, &iVal);
+              if( p->bDescIdx ){
+                iDocid = (i64)((u64)iDocid - iVal);
+              }else{
+                iDocid = (i64)((u64)iDocid + iVal);
+              }
+            }
+          }else{
+            iPos += (iVal - 2);
+            cksum = cksum ^ fts3ChecksumEntry(
+                csr.zTerm, csr.nTerm, iLangid, iIndex, iDocid,
+                (int)iCol, (int)iPos
+            );
+          }
+        }
+      }
+    }
+  }
+  sqlite3Fts3SegReaderFinish(&csr);
+
+  *pRc = rc;
+  return cksum;
+}
+
+/*
+** Check if the contents of the FTS index match the current contents of the
+** content table. If no error occurs and the contents do match, set *pbOk
+** to true and return SQLITE_OK. Or if the contents do not match, set *pbOk
+** to false before returning.
+**
+** If an error occurs (e.g. an OOM or IO error), return an SQLite error
+** code. The final value of *pbOk is undefined in this case.
+*/
+SQLITE_PRIVATE int sqlite3Fts3IntegrityCheck(Fts3Table *p, int *pbOk){
+  int rc = SQLITE_OK;             /* Return code */
+  u64 cksum1 = 0;                 /* Checksum based on FTS index contents */
+  u64 cksum2 = 0;                 /* Checksum based on %_content contents */
+  sqlite3_stmt *pAllLangid = 0;   /* Statement to return all language-ids */
+
+  /* This block calculates the checksum according to the FTS index. */
+  rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
+  if( rc==SQLITE_OK ){
+    int rc2;
+    sqlite3_bind_int(pAllLangid, 1, p->iPrevLangid);
+    sqlite3_bind_int(pAllLangid, 2, p->nIndex);
+    while( rc==SQLITE_OK && sqlite3_step(pAllLangid)==SQLITE_ROW ){
+      int iLangid = sqlite3_column_int(pAllLangid, 0);
+      int i;
+      for(i=0; i<p->nIndex; i++){
+        cksum1 = cksum1 ^ fts3ChecksumIndex(p, iLangid, i, &rc);
+      }
+    }
+    rc2 = sqlite3_reset(pAllLangid);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  /* This block calculates the checksum according to the %_content table */
+  if( rc==SQLITE_OK ){
+    sqlite3_tokenizer_module const *pModule = p->pTokenizer->pModule;
+    sqlite3_stmt *pStmt = 0;
+    char *zSql;
+
+    zSql = sqlite3_mprintf("SELECT %s" , p->zReadExprlist);
+    if( !zSql ){
+      rc = SQLITE_NOMEM;
+    }else{
+      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
+      sqlite3_free(zSql);
+    }
+
+    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      i64 iDocid = sqlite3_column_int64(pStmt, 0);
+      int iLang = langidFromSelect(p, pStmt);
+      int iCol;
+
+      for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
+        if( p->abNotindexed[iCol]==0 ){
+          const char *zText = (const char *)sqlite3_column_text(pStmt, iCol+1);
+          sqlite3_tokenizer_cursor *pT = 0;
+
+          rc = sqlite3Fts3OpenTokenizer(p->pTokenizer, iLang, zText, -1, &pT);
+          while( rc==SQLITE_OK ){
+            char const *zToken;       /* Buffer containing token */
+            int nToken = 0;           /* Number of bytes in token */
+            int iDum1 = 0, iDum2 = 0; /* Dummy variables */
+            int iPos = 0;             /* Position of token in zText */
+
+            rc = pModule->xNext(pT, &zToken, &nToken, &iDum1, &iDum2, &iPos);
+            if( rc==SQLITE_OK ){
+              int i;
+              cksum2 = cksum2 ^ fts3ChecksumEntry(
+                  zToken, nToken, iLang, 0, iDocid, iCol, iPos
+              );
+              for(i=1; i<p->nIndex; i++){
+                if( p->aIndex[i].nPrefix<=nToken ){
+                  cksum2 = cksum2 ^ fts3ChecksumEntry(
+                      zToken, p->aIndex[i].nPrefix, iLang, i, iDocid, iCol, iPos
+                  );
+                }
+              }
+            }
+          }
+          if( pT ) pModule->xClose(pT);
+          if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+        }
+      }
+    }
+
+    sqlite3_finalize(pStmt);
+  }
+
+  if( rc==SQLITE_CORRUPT_VTAB ){
+    rc = SQLITE_OK;
+    *pbOk = 0;
+  }else{
+    *pbOk = (rc==SQLITE_OK && cksum1==cksum2);
+  }
+  return rc;
+}
+
+/*
+** Run the integrity-check. If no error occurs and the current contents of
+** the FTS index are correct, return SQLITE_OK. Or, if the contents of the
+** FTS index are incorrect, return SQLITE_CORRUPT_VTAB.
+**
+** Or, if an error (e.g. an OOM or IO error) occurs, return an SQLite
+** error code.
+**
+** The integrity-check works as follows. For each token and indexed token
+** prefix in the document set, a 64-bit checksum is calculated (by code
+** in fts3ChecksumEntry()) based on the following:
+**
+**     + The index number (0 for the main index, 1 for the first prefix
+**       index etc.),
+**     + The token (or token prefix) text itself,
+**     + The language-id of the row it appears in,
+**     + The docid of the row it appears in,
+**     + The column it appears in, and
+**     + The tokens position within that column.
+**
+** The checksums for all entries in the index are XORed together to create
+** a single checksum for the entire index.
+**
+** The integrity-check code calculates the same checksum in two ways:
+**
+**     1. By scanning the contents of the FTS index, and
+**     2. By scanning and tokenizing the content table.
+**
+** If the two checksums are identical, the integrity-check is deemed to have
+** passed.
+*/
+static int fts3DoIntegrityCheck(
+  Fts3Table *p                    /* FTS3 table handle */
+){
+  int rc;
+  int bOk = 0;
+  rc = sqlite3Fts3IntegrityCheck(p, &bOk);
+  if( rc==SQLITE_OK && bOk==0 ) rc = FTS_CORRUPT_VTAB;
+  return rc;
+}
+
+/*
+** Handle a 'special' INSERT of the form:
+**
+**   "INSERT INTO tbl(tbl) VALUES(<expr>)"
+**
+** Argument pVal contains the result of <expr>. Currently the only
+** meaningful value to insert is the text 'optimize'.
+*/
+static int fts3SpecialInsert(Fts3Table *p, sqlite3_value *pVal){
+  int rc = SQLITE_ERROR;           /* Return Code */
+  const char *zVal = (const char *)sqlite3_value_text(pVal);
+  int nVal = sqlite3_value_bytes(pVal);
+
+  if( !zVal ){
+    return SQLITE_NOMEM;
+  }else if( nVal==8 && 0==sqlite3_strnicmp(zVal, "optimize", 8) ){
+    rc = fts3DoOptimize(p, 0);
+  }else if( nVal==7 && 0==sqlite3_strnicmp(zVal, "rebuild", 7) ){
+    rc = fts3DoRebuild(p);
+  }else if( nVal==15 && 0==sqlite3_strnicmp(zVal, "integrity-check", 15) ){
+    rc = fts3DoIntegrityCheck(p);
+  }else if( nVal>6 && 0==sqlite3_strnicmp(zVal, "merge=", 6) ){
+    rc = fts3DoIncrmerge(p, &zVal[6]);
+  }else if( nVal>10 && 0==sqlite3_strnicmp(zVal, "automerge=", 10) ){
+    rc = fts3DoAutoincrmerge(p, &zVal[10]);
+  }else if( nVal==5 && 0==sqlite3_strnicmp(zVal, "flush", 5) ){
+    rc = sqlite3Fts3PendingTermsFlush(p);
+  }
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+  else{
+    int v;
+    if( nVal>9 && 0==sqlite3_strnicmp(zVal, "nodesize=", 9) ){
+      v = atoi(&zVal[9]);
+      if( v>=24 && v<=p->nPgsz-35 ) p->nNodeSize = v;
+      rc = SQLITE_OK;
+    }else if( nVal>11 && 0==sqlite3_strnicmp(zVal, "maxpending=", 9) ){
+      v = atoi(&zVal[11]);
+      if( v>=64 && v<=FTS3_MAX_PENDING_DATA ) p->nMaxPendingData = v;
+      rc = SQLITE_OK;
+    }else if( nVal>21 && 0==sqlite3_strnicmp(zVal,"test-no-incr-doclist=",21) ){
+      p->bNoIncrDoclist = atoi(&zVal[21]);
+      rc = SQLITE_OK;
+    }else if( nVal>11 && 0==sqlite3_strnicmp(zVal,"mergecount=",11) ){
+      v = atoi(&zVal[11]);
+      if( v>=4 && v<=FTS3_MERGE_COUNT && (v&1)==0 ) p->nMergeCount = v;
+      rc = SQLITE_OK;
+    }
+  }
+#endif
+  return rc;
+}
+
+#ifndef SQLITE_DISABLE_FTS4_DEFERRED
+/*
+** Delete all cached deferred doclists. Deferred doclists are cached
+** (allocated) by the sqlite3Fts3CacheDeferredDoclists() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *pCsr){
+  Fts3DeferredToken *pDef;
+  for(pDef=pCsr->pDeferred; pDef; pDef=pDef->pNext){
+    fts3PendingListDelete(pDef->pList);
+    pDef->pList = 0;
+  }
+}
+
+/*
+** Free all entries in the pCsr->pDeffered list. Entries are added to
+** this list using sqlite3Fts3DeferToken().
+*/
+SQLITE_PRIVATE void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *pCsr){
+  Fts3DeferredToken *pDef;
+  Fts3DeferredToken *pNext;
+  for(pDef=pCsr->pDeferred; pDef; pDef=pNext){
+    pNext = pDef->pNext;
+    fts3PendingListDelete(pDef->pList);
+    sqlite3_free(pDef);
+  }
+  pCsr->pDeferred = 0;
+}
+
+/*
+** Generate deferred-doclists for all tokens in the pCsr->pDeferred list
+** based on the row that pCsr currently points to.
+**
+** A deferred-doclist is like any other doclist with position information
+** included, except that it only contains entries for a single row of the
+** table, not for all rows.
+*/
+SQLITE_PRIVATE int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *pCsr){
+  int rc = SQLITE_OK;             /* Return code */
+  if( pCsr->pDeferred ){
+    int i;                        /* Used to iterate through table columns */
+    sqlite3_int64 iDocid;         /* Docid of the row pCsr points to */
+    Fts3DeferredToken *pDef;      /* Used to iterate through deferred tokens */
+
+    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
+    sqlite3_tokenizer *pT = p->pTokenizer;
+    sqlite3_tokenizer_module const *pModule = pT->pModule;
+
+    assert( pCsr->isRequireSeek==0 );
+    iDocid = sqlite3_column_int64(pCsr->pStmt, 0);
+
+    for(i=0; i<p->nColumn && rc==SQLITE_OK; i++){
+      if( p->abNotindexed[i]==0 ){
+        const char *zText = (const char *)sqlite3_column_text(pCsr->pStmt, i+1);
+        sqlite3_tokenizer_cursor *pTC = 0;
+
+        rc = sqlite3Fts3OpenTokenizer(pT, pCsr->iLangid, zText, -1, &pTC);
+        while( rc==SQLITE_OK ){
+          char const *zToken;       /* Buffer containing token */
+          int nToken = 0;           /* Number of bytes in token */
+          int iDum1 = 0, iDum2 = 0; /* Dummy variables */
+          int iPos = 0;             /* Position of token in zText */
+
+          rc = pModule->xNext(pTC, &zToken, &nToken, &iDum1, &iDum2, &iPos);
+          for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
+            Fts3PhraseToken *pPT = pDef->pToken;
+            if( (pDef->iCol>=p->nColumn || pDef->iCol==i)
+                && (pPT->bFirst==0 || iPos==0)
+                && (pPT->n==nToken || (pPT->isPrefix && pPT->n<nToken))
+                && (0==memcmp(zToken, pPT->z, pPT->n))
+              ){
+              fts3PendingListAppend(&pDef->pList, iDocid, i, iPos, &rc);
+            }
+          }
+        }
+        if( pTC ) pModule->xClose(pTC);
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+      }
+    }
+
+    for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
+      if( pDef->pList ){
+        rc = fts3PendingListAppendVarint(&pDef->pList, 0);
+      }
+    }
+  }
+
+  return rc;
+}
+
+SQLITE_PRIVATE int sqlite3Fts3DeferredTokenList(
+  Fts3DeferredToken *p,
+  char **ppData,
+  int *pnData
+){
+  char *pRet;
+  int nSkip;
+  sqlite3_int64 dummy;
+
+  *ppData = 0;
+  *pnData = 0;
+
+  if( p->pList==0 ){
+    return SQLITE_OK;
+  }
+
+  pRet = (char *)sqlite3_malloc64(p->pList->nData);
+  if( !pRet ) return SQLITE_NOMEM;
+
+  nSkip = sqlite3Fts3GetVarint(p->pList->aData, &dummy);
+  *pnData = p->pList->nData - nSkip;
+  *ppData = pRet;
+
+  memcpy(pRet, &p->pList->aData[nSkip], *pnData);
+  return SQLITE_OK;
+}
+
+/*
+** Add an entry for token pToken to the pCsr->pDeferred list.
+*/
+SQLITE_PRIVATE int sqlite3Fts3DeferToken(
+  Fts3Cursor *pCsr,               /* Fts3 table cursor */
+  Fts3PhraseToken *pToken,        /* Token to defer */
+  int iCol                        /* Column that token must appear in (or -1) */
+){
+  Fts3DeferredToken *pDeferred;
+  pDeferred = sqlite3_malloc64(sizeof(*pDeferred));
+  if( !pDeferred ){
+    return SQLITE_NOMEM;
+  }
+  memset(pDeferred, 0, sizeof(*pDeferred));
+  pDeferred->pToken = pToken;
+  pDeferred->pNext = pCsr->pDeferred;
+  pDeferred->iCol = iCol;
+  pCsr->pDeferred = pDeferred;
+
+  assert( pToken->pDeferred==0 );
+  pToken->pDeferred = pDeferred;
+
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** SQLite value pRowid contains the rowid of a row that may or may not be
+** present in the FTS3 table. If it is, delete it and adjust the contents
+** of subsiduary data structures accordingly.
+*/
+static int fts3DeleteByRowid(
+  Fts3Table *p,
+  sqlite3_value *pRowid,
+  int *pnChng,                    /* IN/OUT: Decrement if row is deleted */
+  u32 *aSzDel
+){
+  int rc = SQLITE_OK;             /* Return code */
+  int bFound = 0;                 /* True if *pRowid really is in the table */
+
+  fts3DeleteTerms(&rc, p, pRowid, aSzDel, &bFound);
+  if( bFound && rc==SQLITE_OK ){
+    int isEmpty = 0;              /* Deleting *pRowid leaves the table empty */
+    rc = fts3IsEmpty(p, pRowid, &isEmpty);
+    if( rc==SQLITE_OK ){
+      if( isEmpty ){
+        /* Deleting this row means the whole table is empty. In this case
+        ** delete the contents of all three tables and throw away any
+        ** data in the pendingTerms hash table.  */
+        rc = fts3DeleteAll(p, 1);
+        *pnChng = 0;
+        memset(aSzDel, 0, sizeof(u32) * (p->nColumn+1) * 2);
+      }else{
+        *pnChng = *pnChng - 1;
+        if( p->zContentTbl==0 ){
+          fts3SqlExec(&rc, p, SQL_DELETE_CONTENT, &pRowid);
+        }
+        if( p->bHasDocsize ){
+          fts3SqlExec(&rc, p, SQL_DELETE_DOCSIZE, &pRowid);
+        }
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function does the work for the xUpdate method of FTS3 virtual
+** tables. The schema of the virtual table being:
+**
+**     CREATE TABLE <table name>(
+**       <user columns>,
+**       <table name> HIDDEN,
+**       docid HIDDEN,
+**       <langid> HIDDEN
+**     );
+**
+**
+*/
+SQLITE_PRIVATE int sqlite3Fts3UpdateMethod(
+  sqlite3_vtab *pVtab,            /* FTS3 vtab object */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  Fts3Table *p = (Fts3Table *)pVtab;
+  int rc = SQLITE_OK;             /* Return Code */
+  u32 *aSzIns = 0;                /* Sizes of inserted documents */
+  u32 *aSzDel = 0;                /* Sizes of deleted documents */
+  int nChng = 0;                  /* Net change in number of documents */
+  int bInsertDone = 0;
+
+  /* At this point it must be known if the %_stat table exists or not.
+  ** So bHasStat may not be 2.  */
+  assert( p->bHasStat==0 || p->bHasStat==1 );
+
+  assert( p->pSegments==0 );
+  assert(
+      nArg==1                     /* DELETE operations */
+   || nArg==(2 + p->nColumn + 3)  /* INSERT or UPDATE operations */
+  );
+
+  /* Check for a "special" INSERT operation. One of the form:
+  **
+  **   INSERT INTO xyz(xyz) VALUES('command');
+  */
+  if( nArg>1
+   && sqlite3_value_type(apVal[0])==SQLITE_NULL
+   && sqlite3_value_type(apVal[p->nColumn+2])!=SQLITE_NULL
+  ){
+    rc = fts3SpecialInsert(p, apVal[p->nColumn+2]);
+    goto update_out;
+  }
+
+  if( nArg>1 && sqlite3_value_int(apVal[2 + p->nColumn + 2])<0 ){
+    rc = SQLITE_CONSTRAINT;
+    goto update_out;
+  }
+
+  /* Allocate space to hold the change in document sizes */
+  aSzDel = sqlite3_malloc64(sizeof(aSzDel[0])*((sqlite3_int64)p->nColumn+1)*2);
+  if( aSzDel==0 ){
+    rc = SQLITE_NOMEM;
+    goto update_out;
+  }
+  aSzIns = &aSzDel[p->nColumn+1];
+  memset(aSzDel, 0, sizeof(aSzDel[0])*(p->nColumn+1)*2);
+
+  rc = fts3Writelock(p);
+  if( rc!=SQLITE_OK ) goto update_out;
+
+  /* If this is an INSERT operation, or an UPDATE that modifies the rowid
+  ** value, then this operation requires constraint handling.
+  **
+  ** If the on-conflict mode is REPLACE, this means that the existing row
+  ** should be deleted from the database before inserting the new row. Or,
+  ** if the on-conflict mode is other than REPLACE, then this method must
+  ** detect the conflict and return SQLITE_CONSTRAINT before beginning to
+  ** modify the database file.
+  */
+  if( nArg>1 && p->zContentTbl==0 ){
+    /* Find the value object that holds the new rowid value. */
+    sqlite3_value *pNewRowid = apVal[3+p->nColumn];
+    if( sqlite3_value_type(pNewRowid)==SQLITE_NULL ){
+      pNewRowid = apVal[1];
+    }
+
+    if( sqlite3_value_type(pNewRowid)!=SQLITE_NULL && (
+        sqlite3_value_type(apVal[0])==SQLITE_NULL
+     || sqlite3_value_int64(apVal[0])!=sqlite3_value_int64(pNewRowid)
+    )){
+      /* The new rowid is not NULL (in this case the rowid will be
+      ** automatically assigned and there is no chance of a conflict), and
+      ** the statement is either an INSERT or an UPDATE that modifies the
+      ** rowid column. So if the conflict mode is REPLACE, then delete any
+      ** existing row with rowid=pNewRowid.
+      **
+      ** Or, if the conflict mode is not REPLACE, insert the new record into
+      ** the %_content table. If we hit the duplicate rowid constraint (or any
+      ** other error) while doing so, return immediately.
+      **
+      ** This branch may also run if pNewRowid contains a value that cannot
+      ** be losslessly converted to an integer. In this case, the eventual
+      ** call to fts3InsertData() (either just below or further on in this
+      ** function) will return SQLITE_MISMATCH. If fts3DeleteByRowid is
+      ** invoked, it will delete zero rows (since no row will have
+      ** docid=$pNewRowid if $pNewRowid is not an integer value).
+      */
+      if( sqlite3_vtab_on_conflict(p->db)==SQLITE_REPLACE ){
+        rc = fts3DeleteByRowid(p, pNewRowid, &nChng, aSzDel);
+      }else{
+        rc = fts3InsertData(p, apVal, pRowid);
+        bInsertDone = 1;
+      }
+    }
+  }
+  if( rc!=SQLITE_OK ){
+    goto update_out;
+  }
+
+  /* If this is a DELETE or UPDATE operation, remove the old record. */
+  if( sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
+    assert( sqlite3_value_type(apVal[0])==SQLITE_INTEGER );
+    rc = fts3DeleteByRowid(p, apVal[0], &nChng, aSzDel);
+  }
+
+  /* If this is an INSERT or UPDATE operation, insert the new record. */
+  if( nArg>1 && rc==SQLITE_OK ){
+    int iLangid = sqlite3_value_int(apVal[2 + p->nColumn + 2]);
+    if( bInsertDone==0 ){
+      rc = fts3InsertData(p, apVal, pRowid);
+      if( rc==SQLITE_CONSTRAINT && p->zContentTbl==0 ){
+        rc = FTS_CORRUPT_VTAB;
+      }
+    }
+    if( rc==SQLITE_OK ){
+      rc = fts3PendingTermsDocid(p, 0, iLangid, *pRowid);
+    }
+    if( rc==SQLITE_OK ){
+      assert( p->iPrevDocid==*pRowid );
+      rc = fts3InsertTerms(p, iLangid, apVal, aSzIns);
+    }
+    if( p->bHasDocsize ){
+      fts3InsertDocsize(&rc, p, aSzIns);
+    }
+    nChng++;
+  }
+
+  if( p->bFts4 ){
+    fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nChng);
+  }
+
+ update_out:
+  sqlite3_free(aSzDel);
+  sqlite3Fts3SegmentsClose(p);
+  return rc;
+}
+
+/*
+** Flush any data in the pending-terms hash table to disk. If successful,
+** merge all segments in the database (including the new segment, if
+** there was any data to flush) into a single segment.
+*/
+SQLITE_PRIVATE int sqlite3Fts3Optimize(Fts3Table *p){
+  int rc;
+  rc = sqlite3_exec(p->db, "SAVEPOINT fts3", 0, 0, 0);
+  if( rc==SQLITE_OK ){
+    rc = fts3DoOptimize(p, 1);
+    if( rc==SQLITE_OK || rc==SQLITE_DONE ){
+      int rc2 = sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
+      if( rc2!=SQLITE_OK ) rc = rc2;
+    }else{
+      sqlite3_exec(p->db, "ROLLBACK TO fts3", 0, 0, 0);
+      sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
+    }
+  }
+  sqlite3Fts3SegmentsClose(p);
+  return rc;
+}
+
+#endif
+
+/************** End of fts3_write.c ******************************************/
+/************** Begin file fts3_snippet.c ************************************/
+/*
+** 2009 Oct 23
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+#ifndef SQLITE_AMALGAMATION
+typedef sqlite3_int64 i64;
+#endif
+
+/*
+** Characters that may appear in the second argument to matchinfo().
+*/
+#define FTS3_MATCHINFO_NPHRASE   'p'        /* 1 value */
+#define FTS3_MATCHINFO_NCOL      'c'        /* 1 value */
+#define FTS3_MATCHINFO_NDOC      'n'        /* 1 value */
+#define FTS3_MATCHINFO_AVGLENGTH 'a'        /* nCol values */
+#define FTS3_MATCHINFO_LENGTH    'l'        /* nCol values */
+#define FTS3_MATCHINFO_LCS       's'        /* nCol values */
+#define FTS3_MATCHINFO_HITS      'x'        /* 3*nCol*nPhrase values */
+#define FTS3_MATCHINFO_LHITS     'y'        /* nCol*nPhrase values */
+#define FTS3_MATCHINFO_LHITS_BM  'b'        /* nCol*nPhrase values */
+
+/*
+** The default value for the second argument to matchinfo().
+*/
+#define FTS3_MATCHINFO_DEFAULT   "pcx"
+
+
+/*
+** Used as an sqlite3Fts3ExprIterate() context when loading phrase doclists to
+** Fts3Expr.aDoclist[]/nDoclist.
+*/
+typedef struct LoadDoclistCtx LoadDoclistCtx;
+struct LoadDoclistCtx {
+  Fts3Cursor *pCsr;               /* FTS3 Cursor */
+  int nPhrase;                    /* Number of phrases seen so far */
+  int nToken;                     /* Number of tokens seen so far */
+};
+
+/*
+** The following types are used as part of the implementation of the
+** fts3BestSnippet() routine.
+*/
+typedef struct SnippetIter SnippetIter;
+typedef struct SnippetPhrase SnippetPhrase;
+typedef struct SnippetFragment SnippetFragment;
+
+struct SnippetIter {
+  Fts3Cursor *pCsr;               /* Cursor snippet is being generated from */
+  int iCol;                       /* Extract snippet from this column */
+  int nSnippet;                   /* Requested snippet length (in tokens) */
+  int nPhrase;                    /* Number of phrases in query */
+  SnippetPhrase *aPhrase;         /* Array of size nPhrase */
+  int iCurrent;                   /* First token of current snippet */
+};
+
+struct SnippetPhrase {
+  int nToken;                     /* Number of tokens in phrase */
+  char *pList;                    /* Pointer to start of phrase position list */
+  i64 iHead;                      /* Next value in position list */
+  char *pHead;                    /* Position list data following iHead */
+  i64 iTail;                      /* Next value in trailing position list */
+  char *pTail;                    /* Position list data following iTail */
+};
+
+struct SnippetFragment {
+  int iCol;                       /* Column snippet is extracted from */
+  int iPos;                       /* Index of first token in snippet */
+  u64 covered;                    /* Mask of query phrases covered */
+  u64 hlmask;                     /* Mask of snippet terms to highlight */
+};
+
+/*
+** This type is used as an sqlite3Fts3ExprIterate() context object while
+** accumulating the data returned by the matchinfo() function.
+*/
+typedef struct MatchInfo MatchInfo;
+struct MatchInfo {
+  Fts3Cursor *pCursor;            /* FTS3 Cursor */
+  int nCol;                       /* Number of columns in table */
+  int nPhrase;                    /* Number of matchable phrases in query */
+  sqlite3_int64 nDoc;             /* Number of docs in database */
+  char flag;
+  u32 *aMatchinfo;                /* Pre-allocated buffer */
+};
+
+/*
+** An instance of this structure is used to manage a pair of buffers, each
+** (nElem * sizeof(u32)) bytes in size. See the MatchinfoBuffer code below
+** for details.
+*/
+struct MatchinfoBuffer {
+  u8 aRef[3];
+  int nElem;
+  int bGlobal;                    /* Set if global data is loaded */
+  char *zMatchinfo;
+  u32 aMatchinfo[1];
+};
+
+
+/*
+** The snippet() and offsets() functions both return text values. An instance
+** of the following structure is used to accumulate those values while the
+** functions are running. See fts3StringAppend() for details.
+*/
+typedef struct StrBuffer StrBuffer;
+struct StrBuffer {
+  char *z;                        /* Pointer to buffer containing string */
+  int n;                          /* Length of z in bytes (excl. nul-term) */
+  int nAlloc;                     /* Allocated size of buffer z in bytes */
+};
+
+
+/*************************************************************************
+** Start of MatchinfoBuffer code.
+*/
+
+/*
+** Allocate a two-slot MatchinfoBuffer object.
+*/
+static MatchinfoBuffer *fts3MIBufferNew(size_t nElem, const char *zMatchinfo){
+  MatchinfoBuffer *pRet;
+  sqlite3_int64 nByte = sizeof(u32) * (2*(sqlite3_int64)nElem + 1)
+                           + sizeof(MatchinfoBuffer);
+  sqlite3_int64 nStr = strlen(zMatchinfo);
+
+  pRet = sqlite3Fts3MallocZero(nByte + nStr+1);
+  if( pRet ){
+    pRet->aMatchinfo[0] = (u8*)(&pRet->aMatchinfo[1]) - (u8*)pRet;
+    pRet->aMatchinfo[1+nElem] = pRet->aMatchinfo[0]
+                                      + sizeof(u32)*((int)nElem+1);
+    pRet->nElem = (int)nElem;
+    pRet->zMatchinfo = ((char*)pRet) + nByte;
+    memcpy(pRet->zMatchinfo, zMatchinfo, nStr+1);
+    pRet->aRef[0] = 1;
+  }
+
+  return pRet;
+}
+
+static void fts3MIBufferFree(void *p){
+  MatchinfoBuffer *pBuf = (MatchinfoBuffer*)((u8*)p - ((u32*)p)[-1]);
+
+  assert( (u32*)p==&pBuf->aMatchinfo[1]
+       || (u32*)p==&pBuf->aMatchinfo[pBuf->nElem+2]
+  );
+  if( (u32*)p==&pBuf->aMatchinfo[1] ){
+    pBuf->aRef[1] = 0;
+  }else{
+    pBuf->aRef[2] = 0;
+  }
+
+  if( pBuf->aRef[0]==0 && pBuf->aRef[1]==0 && pBuf->aRef[2]==0 ){
+    sqlite3_free(pBuf);
+  }
+}
+
+static void (*fts3MIBufferAlloc(MatchinfoBuffer *p, u32 **paOut))(void*){
+  void (*xRet)(void*) = 0;
+  u32 *aOut = 0;
+
+  if( p->aRef[1]==0 ){
+    p->aRef[1] = 1;
+    aOut = &p->aMatchinfo[1];
+    xRet = fts3MIBufferFree;
+  }
+  else if( p->aRef[2]==0 ){
+    p->aRef[2] = 1;
+    aOut = &p->aMatchinfo[p->nElem+2];
+    xRet = fts3MIBufferFree;
+  }else{
+    aOut = (u32*)sqlite3_malloc64(p->nElem * sizeof(u32));
+    if( aOut ){
+      xRet = sqlite3_free;
+      if( p->bGlobal ) memcpy(aOut, &p->aMatchinfo[1], p->nElem*sizeof(u32));
+    }
+  }
+
+  *paOut = aOut;
+  return xRet;
+}
+
+static void fts3MIBufferSetGlobal(MatchinfoBuffer *p){
+  p->bGlobal = 1;
+  memcpy(&p->aMatchinfo[2+p->nElem], &p->aMatchinfo[1], p->nElem*sizeof(u32));
+}
+
+/*
+** Free a MatchinfoBuffer object allocated using fts3MIBufferNew()
+*/
+SQLITE_PRIVATE void sqlite3Fts3MIBufferFree(MatchinfoBuffer *p){
+  if( p ){
+    assert( p->aRef[0]==1 );
+    p->aRef[0] = 0;
+    if( p->aRef[0]==0 && p->aRef[1]==0 && p->aRef[2]==0 ){
+      sqlite3_free(p);
+    }
+  }
+}
+
+/*
+** End of MatchinfoBuffer code.
+*************************************************************************/
+
+
+/*
+** This function is used to help iterate through a position-list. A position
+** list is a list of unique integers, sorted from smallest to largest. Each
+** element of the list is represented by an FTS3 varint that takes the value
+** of the difference between the current element and the previous one plus
+** two. For example, to store the position-list:
+**
+**     4 9 113
+**
+** the three varints:
+**
+**     6 7 106
+**
+** are encoded.
+**
+** When this function is called, *pp points to the start of an element of
+** the list. *piPos contains the value of the previous entry in the list.
+** After it returns, *piPos contains the value of the next element of the
+** list and *pp is advanced to the following varint.
+*/
+static void fts3GetDeltaPosition(char **pp, i64 *piPos){
+  int iVal;
+  *pp += fts3GetVarint32(*pp, &iVal);
+  *piPos += (iVal-2);
+}
+
+/*
+** Helper function for sqlite3Fts3ExprIterate() (see below).
+*/
+static int fts3ExprIterate2(
+  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
+  int *piPhrase,                  /* Pointer to phrase counter */
+  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
+  void *pCtx                      /* Second argument to pass to callback */
+){
+  int rc;                         /* Return code */
+  int eType = pExpr->eType;     /* Type of expression node pExpr */
+
+  if( eType!=FTSQUERY_PHRASE ){
+    assert( pExpr->pLeft && pExpr->pRight );
+    rc = fts3ExprIterate2(pExpr->pLeft, piPhrase, x, pCtx);
+    if( rc==SQLITE_OK && eType!=FTSQUERY_NOT ){
+      rc = fts3ExprIterate2(pExpr->pRight, piPhrase, x, pCtx);
+    }
+  }else{
+    rc = x(pExpr, *piPhrase, pCtx);
+    (*piPhrase)++;
+  }
+  return rc;
+}
+
+/*
+** Iterate through all phrase nodes in an FTS3 query, except those that
+** are part of a sub-tree that is the right-hand-side of a NOT operator.
+** For each phrase node found, the supplied callback function is invoked.
+**
+** If the callback function returns anything other than SQLITE_OK,
+** the iteration is abandoned and the error code returned immediately.
+** Otherwise, SQLITE_OK is returned after a callback has been made for
+** all eligible phrase nodes.
+*/
+SQLITE_PRIVATE int sqlite3Fts3ExprIterate(
+  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
+  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
+  void *pCtx                      /* Second argument to pass to callback */
+){
+  int iPhrase = 0;                /* Variable used as the phrase counter */
+  return fts3ExprIterate2(pExpr, &iPhrase, x, pCtx);
+}
+
+/*
+** This is an sqlite3Fts3ExprIterate() callback used while loading the
+** doclists for each phrase into Fts3Expr.aDoclist[]/nDoclist. See also
+** fts3ExprLoadDoclists().
+*/
+static int fts3ExprLoadDoclistsCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  int rc = SQLITE_OK;
+  Fts3Phrase *pPhrase = pExpr->pPhrase;
+  LoadDoclistCtx *p = (LoadDoclistCtx *)ctx;
+
+  UNUSED_PARAMETER(iPhrase);
+
+  p->nPhrase++;
+  p->nToken += pPhrase->nToken;
+
+  return rc;
+}
+
+/*
+** Load the doclists for each phrase in the query associated with FTS3 cursor
+** pCsr.
+**
+** If pnPhrase is not NULL, then *pnPhrase is set to the number of matchable
+** phrases in the expression (all phrases except those directly or
+** indirectly descended from the right-hand-side of a NOT operator). If
+** pnToken is not NULL, then it is set to the number of tokens in all
+** matchable phrases of the expression.
+*/
+static int fts3ExprLoadDoclists(
+  Fts3Cursor *pCsr,               /* Fts3 cursor for current query */
+  int *pnPhrase,                  /* OUT: Number of phrases in query */
+  int *pnToken                    /* OUT: Number of tokens in query */
+){
+  int rc;                         /* Return Code */
+  LoadDoclistCtx sCtx = {0,0,0};  /* Context for sqlite3Fts3ExprIterate() */
+  sCtx.pCsr = pCsr;
+  rc = sqlite3Fts3ExprIterate(pCsr->pExpr,fts3ExprLoadDoclistsCb,(void*)&sCtx);
+  if( pnPhrase ) *pnPhrase = sCtx.nPhrase;
+  if( pnToken ) *pnToken = sCtx.nToken;
+  return rc;
+}
+
+static int fts3ExprPhraseCountCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  (*(int *)ctx)++;
+  pExpr->iPhrase = iPhrase;
+  return SQLITE_OK;
+}
+static int fts3ExprPhraseCount(Fts3Expr *pExpr){
+  int nPhrase = 0;
+  (void)sqlite3Fts3ExprIterate(pExpr, fts3ExprPhraseCountCb, (void *)&nPhrase);
+  return nPhrase;
+}
+
+/*
+** Advance the position list iterator specified by the first two
+** arguments so that it points to the first element with a value greater
+** than or equal to parameter iNext.
+*/
+static void fts3SnippetAdvance(char **ppIter, i64 *piIter, int iNext){
+  char *pIter = *ppIter;
+  if( pIter ){
+    i64 iIter = *piIter;
+
+    while( iIter<iNext ){
+      if( 0==(*pIter & 0xFE) ){
+        iIter = -1;
+        pIter = 0;
+        break;
+      }
+      fts3GetDeltaPosition(&pIter, &iIter);
+    }
+
+    *piIter = iIter;
+    *ppIter = pIter;
+  }
+}
+
+/*
+** Advance the snippet iterator to the next candidate snippet.
+*/
+static int fts3SnippetNextCandidate(SnippetIter *pIter){
+  int i;                          /* Loop counter */
+
+  if( pIter->iCurrent<0 ){
+    /* The SnippetIter object has just been initialized. The first snippet
+    ** candidate always starts at offset 0 (even if this candidate has a
+    ** score of 0.0).
+    */
+    pIter->iCurrent = 0;
+
+    /* Advance the 'head' iterator of each phrase to the first offset that
+    ** is greater than or equal to (iNext+nSnippet).
+    */
+    for(i=0; i<pIter->nPhrase; i++){
+      SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+      fts3SnippetAdvance(&pPhrase->pHead, &pPhrase->iHead, pIter->nSnippet);
+    }
+  }else{
+    int iStart;
+    int iEnd = 0x7FFFFFFF;
+
+    for(i=0; i<pIter->nPhrase; i++){
+      SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+      if( pPhrase->pHead && pPhrase->iHead<iEnd ){
+        iEnd = pPhrase->iHead;
+      }
+    }
+    if( iEnd==0x7FFFFFFF ){
+      return 1;
+    }
+
+    assert( pIter->nSnippet>=0 );
+    pIter->iCurrent = iStart = iEnd - pIter->nSnippet + 1;
+    for(i=0; i<pIter->nPhrase; i++){
+      SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+      fts3SnippetAdvance(&pPhrase->pHead, &pPhrase->iHead, iEnd+1);
+      fts3SnippetAdvance(&pPhrase->pTail, &pPhrase->iTail, iStart);
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Retrieve information about the current candidate snippet of snippet
+** iterator pIter.
+*/
+static void fts3SnippetDetails(
+  SnippetIter *pIter,             /* Snippet iterator */
+  u64 mCovered,                   /* Bitmask of phrases already covered */
+  int *piToken,                   /* OUT: First token of proposed snippet */
+  int *piScore,                   /* OUT: "Score" for this snippet */
+  u64 *pmCover,                   /* OUT: Bitmask of phrases covered */
+  u64 *pmHighlight                /* OUT: Bitmask of terms to highlight */
+){
+  int iStart = pIter->iCurrent;   /* First token of snippet */
+  int iScore = 0;                 /* Score of this snippet */
+  int i;                          /* Loop counter */
+  u64 mCover = 0;                 /* Mask of phrases covered by this snippet */
+  u64 mHighlight = 0;             /* Mask of tokens to highlight in snippet */
+
+  for(i=0; i<pIter->nPhrase; i++){
+    SnippetPhrase *pPhrase = &pIter->aPhrase[i];
+    if( pPhrase->pTail ){
+      char *pCsr = pPhrase->pTail;
+      i64 iCsr = pPhrase->iTail;
+
+      while( iCsr<(iStart+pIter->nSnippet) && iCsr>=iStart ){
+        int j;
+        u64 mPhrase = (u64)1 << (i%64);
+        u64 mPos = (u64)1 << (iCsr - iStart);
+        assert( iCsr>=iStart && (iCsr - iStart)<=64 );
+        assert( i>=0 );
+        if( (mCover|mCovered)&mPhrase ){
+          iScore++;
+        }else{
+          iScore += 1000;
+        }
+        mCover |= mPhrase;
+
+        for(j=0; j<pPhrase->nToken && j<pIter->nSnippet; j++){
+          mHighlight |= (mPos>>j);
+        }
+
+        if( 0==(*pCsr & 0x0FE) ) break;
+        fts3GetDeltaPosition(&pCsr, &iCsr);
+      }
+    }
+  }
+
+  /* Set the output variables before returning. */
+  *piToken = iStart;
+  *piScore = iScore;
+  *pmCover = mCover;
+  *pmHighlight = mHighlight;
+}
+
+/*
+** This function is an sqlite3Fts3ExprIterate() callback used by
+** fts3BestSnippet().  Each invocation populates an element of the
+** SnippetIter.aPhrase[] array.
+*/
+static int fts3SnippetFindPositions(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  SnippetIter *p = (SnippetIter *)ctx;
+  SnippetPhrase *pPhrase = &p->aPhrase[iPhrase];
+  char *pCsr;
+  int rc;
+
+  pPhrase->nToken = pExpr->pPhrase->nToken;
+  rc = sqlite3Fts3EvalPhrasePoslist(p->pCsr, pExpr, p->iCol, &pCsr);
+  assert( rc==SQLITE_OK || pCsr==0 );
+  if( pCsr ){
+    i64 iFirst = 0;
+    pPhrase->pList = pCsr;
+    fts3GetDeltaPosition(&pCsr, &iFirst);
+    if( iFirst<0 ){
+      rc = FTS_CORRUPT_VTAB;
+    }else{
+      pPhrase->pHead = pCsr;
+      pPhrase->pTail = pCsr;
+      pPhrase->iHead = iFirst;
+      pPhrase->iTail = iFirst;
+    }
+  }else{
+    assert( rc!=SQLITE_OK || (
+       pPhrase->pList==0 && pPhrase->pHead==0 && pPhrase->pTail==0
+    ));
+  }
+
+  return rc;
+}
+
+/*
+** Select the fragment of text consisting of nFragment contiguous tokens
+** from column iCol that represent the "best" snippet. The best snippet
+** is the snippet with the highest score, where scores are calculated
+** by adding:
+**
+**   (a) +1 point for each occurrence of a matchable phrase in the snippet.
+**
+**   (b) +1000 points for the first occurrence of each matchable phrase in
+**       the snippet for which the corresponding mCovered bit is not set.
+**
+** The selected snippet parameters are stored in structure *pFragment before
+** returning. The score of the selected snippet is stored in *piScore
+** before returning.
+*/
+static int fts3BestSnippet(
+  int nSnippet,                   /* Desired snippet length */
+  Fts3Cursor *pCsr,               /* Cursor to create snippet for */
+  int iCol,                       /* Index of column to create snippet from */
+  u64 mCovered,                   /* Mask of phrases already covered */
+  u64 *pmSeen,                    /* IN/OUT: Mask of phrases seen */
+  SnippetFragment *pFragment,     /* OUT: Best snippet found */
+  int *piScore                    /* OUT: Score of snippet pFragment */
+){
+  int rc;                         /* Return Code */
+  int nList;                      /* Number of phrases in expression */
+  SnippetIter sIter;              /* Iterates through snippet candidates */
+  sqlite3_int64 nByte;            /* Number of bytes of space to allocate */
+  int iBestScore = -1;            /* Best snippet score found so far */
+  int i;                          /* Loop counter */
+
+  memset(&sIter, 0, sizeof(sIter));
+
+  /* Iterate through the phrases in the expression to count them. The same
+  ** callback makes sure the doclists are loaded for each phrase.
+  */
+  rc = fts3ExprLoadDoclists(pCsr, &nList, 0);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* Now that it is known how many phrases there are, allocate and zero
+  ** the required space using malloc().
+  */
+  nByte = sizeof(SnippetPhrase) * nList;
+  sIter.aPhrase = (SnippetPhrase *)sqlite3Fts3MallocZero(nByte);
+  if( !sIter.aPhrase ){
+    return SQLITE_NOMEM;
+  }
+
+  /* Initialize the contents of the SnippetIter object. Then iterate through
+  ** the set of phrases in the expression to populate the aPhrase[] array.
+  */
+  sIter.pCsr = pCsr;
+  sIter.iCol = iCol;
+  sIter.nSnippet = nSnippet;
+  sIter.nPhrase = nList;
+  sIter.iCurrent = -1;
+  rc = sqlite3Fts3ExprIterate(
+      pCsr->pExpr, fts3SnippetFindPositions, (void*)&sIter
+  );
+  if( rc==SQLITE_OK ){
+
+    /* Set the *pmSeen output variable. */
+    for(i=0; i<nList; i++){
+      if( sIter.aPhrase[i].pHead ){
+        *pmSeen |= (u64)1 << (i%64);
+      }
+    }
+
+    /* Loop through all candidate snippets. Store the best snippet in
+     ** *pFragment. Store its associated 'score' in iBestScore.
+     */
+    pFragment->iCol = iCol;
+    while( !fts3SnippetNextCandidate(&sIter) ){
+      int iPos;
+      int iScore;
+      u64 mCover;
+      u64 mHighlite;
+      fts3SnippetDetails(&sIter, mCovered, &iPos, &iScore, &mCover,&mHighlite);
+      assert( iScore>=0 );
+      if( iScore>iBestScore ){
+        pFragment->iPos = iPos;
+        pFragment->hlmask = mHighlite;
+        pFragment->covered = mCover;
+        iBestScore = iScore;
+      }
+    }
+
+    *piScore = iBestScore;
+  }
+  sqlite3_free(sIter.aPhrase);
+  return rc;
+}
+
+
+/*
+** Append a string to the string-buffer passed as the first argument.
+**
+** If nAppend is negative, then the length of the string zAppend is
+** determined using strlen().
+*/
+static int fts3StringAppend(
+  StrBuffer *pStr,                /* Buffer to append to */
+  const char *zAppend,            /* Pointer to data to append to buffer */
+  int nAppend                     /* Size of zAppend in bytes (or -1) */
+){
+  if( nAppend<0 ){
+    nAppend = (int)strlen(zAppend);
+  }
+
+  /* If there is insufficient space allocated at StrBuffer.z, use realloc()
+  ** to grow the buffer until so that it is big enough to accomadate the
+  ** appended data.
+  */
+  if( pStr->n+nAppend+1>=pStr->nAlloc ){
+    sqlite3_int64 nAlloc = pStr->nAlloc+(sqlite3_int64)nAppend+100;
+    char *zNew = sqlite3_realloc64(pStr->z, nAlloc);
+    if( !zNew ){
+      return SQLITE_NOMEM;
+    }
+    pStr->z = zNew;
+    pStr->nAlloc = nAlloc;
+  }
+  assert( pStr->z!=0 && (pStr->nAlloc >= pStr->n+nAppend+1) );
+
+  /* Append the data to the string buffer. */
+  memcpy(&pStr->z[pStr->n], zAppend, nAppend);
+  pStr->n += nAppend;
+  pStr->z[pStr->n] = '\0';
+
+  return SQLITE_OK;
+}
+
+/*
+** The fts3BestSnippet() function often selects snippets that end with a
+** query term. That is, the final term of the snippet is always a term
+** that requires highlighting. For example, if 'X' is a highlighted term
+** and '.' is a non-highlighted term, BestSnippet() may select:
+**
+**     ........X.....X
+**
+** This function "shifts" the beginning of the snippet forward in the
+** document so that there are approximately the same number of
+** non-highlighted terms to the right of the final highlighted term as there
+** are to the left of the first highlighted term. For example, to this:
+**
+**     ....X.....X....
+**
+** This is done as part of extracting the snippet text, not when selecting
+** the snippet. Snippet selection is done based on doclists only, so there
+** is no way for fts3BestSnippet() to know whether or not the document
+** actually contains terms that follow the final highlighted term.
+*/
+static int fts3SnippetShift(
+  Fts3Table *pTab,                /* FTS3 table snippet comes from */
+  int iLangid,                    /* Language id to use in tokenizing */
+  int nSnippet,                   /* Number of tokens desired for snippet */
+  const char *zDoc,               /* Document text to extract snippet from */
+  int nDoc,                       /* Size of buffer zDoc in bytes */
+  int *piPos,                     /* IN/OUT: First token of snippet */
+  u64 *pHlmask                    /* IN/OUT: Mask of tokens to highlight */
+){
+  u64 hlmask = *pHlmask;          /* Local copy of initial highlight-mask */
+
+  if( hlmask ){
+    int nLeft;                    /* Tokens to the left of first highlight */
+    int nRight;                   /* Tokens to the right of last highlight */
+    int nDesired;                 /* Ideal number of tokens to shift forward */
+
+    for(nLeft=0; !(hlmask & ((u64)1 << nLeft)); nLeft++);
+    for(nRight=0; !(hlmask & ((u64)1 << (nSnippet-1-nRight))); nRight++);
+    assert( (nSnippet-1-nRight)<=63 && (nSnippet-1-nRight)>=0 );
+    nDesired = (nLeft-nRight)/2;
+
+    /* Ideally, the start of the snippet should be pushed forward in the
+    ** document nDesired tokens. This block checks if there are actually
+    ** nDesired tokens to the right of the snippet. If so, *piPos and
+    ** *pHlMask are updated to shift the snippet nDesired tokens to the
+    ** right. Otherwise, the snippet is shifted by the number of tokens
+    ** available.
+    */
+    if( nDesired>0 ){
+      int nShift;                 /* Number of tokens to shift snippet by */
+      int iCurrent = 0;           /* Token counter */
+      int rc;                     /* Return Code */
+      sqlite3_tokenizer_module *pMod;
+      sqlite3_tokenizer_cursor *pC;
+      pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
+
+      /* Open a cursor on zDoc/nDoc. Check if there are (nSnippet+nDesired)
+      ** or more tokens in zDoc/nDoc.
+      */
+      rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, iLangid, zDoc, nDoc, &pC);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      while( rc==SQLITE_OK && iCurrent<(nSnippet+nDesired) ){
+        const char *ZDUMMY; int DUMMY1 = 0, DUMMY2 = 0, DUMMY3 = 0;
+        rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &DUMMY2, &DUMMY3, &iCurrent);
+      }
+      pMod->xClose(pC);
+      if( rc!=SQLITE_OK && rc!=SQLITE_DONE ){ return rc; }
+
+      nShift = (rc==SQLITE_DONE)+iCurrent-nSnippet;
+      assert( nShift<=nDesired );
+      if( nShift>0 ){
+        *piPos += nShift;
+        *pHlmask = hlmask >> nShift;
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Extract the snippet text for fragment pFragment from cursor pCsr and
+** append it to string buffer pOut.
+*/
+static int fts3SnippetText(
+  Fts3Cursor *pCsr,               /* FTS3 Cursor */
+  SnippetFragment *pFragment,     /* Snippet to extract */
+  int iFragment,                  /* Fragment number */
+  int isLast,                     /* True for final fragment in snippet */
+  int nSnippet,                   /* Number of tokens in extracted snippet */
+  const char *zOpen,              /* String inserted before highlighted term */
+  const char *zClose,             /* String inserted after highlighted term */
+  const char *zEllipsis,          /* String inserted between snippets */
+  StrBuffer *pOut                 /* Write output here */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc;                         /* Return code */
+  const char *zDoc;               /* Document text to extract snippet from */
+  int nDoc;                       /* Size of zDoc in bytes */
+  int iCurrent = 0;               /* Current token number of document */
+  int iEnd = 0;                   /* Byte offset of end of current token */
+  int isShiftDone = 0;            /* True after snippet is shifted */
+  int iPos = pFragment->iPos;     /* First token of snippet */
+  u64 hlmask = pFragment->hlmask; /* Highlight-mask for snippet */
+  int iCol = pFragment->iCol+1;   /* Query column to extract text from */
+  sqlite3_tokenizer_module *pMod; /* Tokenizer module methods object */
+  sqlite3_tokenizer_cursor *pC;   /* Tokenizer cursor open on zDoc/nDoc */
+
+  zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol);
+  if( zDoc==0 ){
+    if( sqlite3_column_type(pCsr->pStmt, iCol)!=SQLITE_NULL ){
+      return SQLITE_NOMEM;
+    }
+    return SQLITE_OK;
+  }
+  nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol);
+
+  /* Open a token cursor on the document. */
+  pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
+  rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, pCsr->iLangid, zDoc,nDoc,&pC);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  while( rc==SQLITE_OK ){
+    const char *ZDUMMY;           /* Dummy argument used with tokenizer */
+    int DUMMY1 = -1;              /* Dummy argument used with tokenizer */
+    int iBegin = 0;               /* Offset in zDoc of start of token */
+    int iFin = 0;                 /* Offset in zDoc of end of token */
+    int isHighlight = 0;          /* True for highlighted terms */
+
+    /* Variable DUMMY1 is initialized to a negative value above. Elsewhere
+    ** in the FTS code the variable that the third argument to xNext points to
+    ** is initialized to zero before the first (*but not necessarily
+    ** subsequent*) call to xNext(). This is done for a particular application
+    ** that needs to know whether or not the tokenizer is being used for
+    ** snippet generation or for some other purpose.
+    **
+    ** Extreme care is required when writing code to depend on this
+    ** initialization. It is not a documented part of the tokenizer interface.
+    ** If a tokenizer is used directly by any code outside of FTS, this
+    ** convention might not be respected.  */
+    rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &iBegin, &iFin, &iCurrent);
+    if( rc!=SQLITE_OK ){
+      if( rc==SQLITE_DONE ){
+        /* Special case - the last token of the snippet is also the last token
+        ** of the column. Append any punctuation that occurred between the end
+        ** of the previous token and the end of the document to the output.
+        ** Then break out of the loop. */
+        rc = fts3StringAppend(pOut, &zDoc[iEnd], -1);
+      }
+      break;
+    }
+    if( iCurrent<iPos ){ continue; }
+
+    if( !isShiftDone ){
+      int n = nDoc - iBegin;
+      rc = fts3SnippetShift(
+          pTab, pCsr->iLangid, nSnippet, &zDoc[iBegin], n, &iPos, &hlmask
+      );
+      isShiftDone = 1;
+
+      /* Now that the shift has been done, check if the initial "..." are
+      ** required. They are required if (a) this is not the first fragment,
+      ** or (b) this fragment does not begin at position 0 of its column.
+      */
+      if( rc==SQLITE_OK ){
+        if( iPos>0 || iFragment>0 ){
+          rc = fts3StringAppend(pOut, zEllipsis, -1);
+        }else if( iBegin ){
+          rc = fts3StringAppend(pOut, zDoc, iBegin);
+        }
+      }
+      if( rc!=SQLITE_OK || iCurrent<iPos ) continue;
+    }
+
+    if( iCurrent>=(iPos+nSnippet) ){
+      if( isLast ){
+        rc = fts3StringAppend(pOut, zEllipsis, -1);
+      }
+      break;
+    }
+
+    /* Set isHighlight to true if this term should be highlighted. */
+    isHighlight = (hlmask & ((u64)1 << (iCurrent-iPos)))!=0;
+
+    if( iCurrent>iPos ) rc = fts3StringAppend(pOut, &zDoc[iEnd], iBegin-iEnd);
+    if( rc==SQLITE_OK && isHighlight ) rc = fts3StringAppend(pOut, zOpen, -1);
+    if( rc==SQLITE_OK ) rc = fts3StringAppend(pOut, &zDoc[iBegin], iFin-iBegin);
+    if( rc==SQLITE_OK && isHighlight ) rc = fts3StringAppend(pOut, zClose, -1);
+
+    iEnd = iFin;
+  }
+
+  pMod->xClose(pC);
+  return rc;
+}
+
+
+/*
+** This function is used to count the entries in a column-list (a
+** delta-encoded list of term offsets within a single column of a single
+** row). When this function is called, *ppCollist should point to the
+** beginning of the first varint in the column-list (the varint that
+** contains the position of the first matching term in the column data).
+** Before returning, *ppCollist is set to point to the first byte after
+** the last varint in the column-list (either the 0x00 signifying the end
+** of the position-list, or the 0x01 that precedes the column number of
+** the next column in the position-list).
+**
+** The number of elements in the column-list is returned.
+*/
+static int fts3ColumnlistCount(char **ppCollist){
+  char *pEnd = *ppCollist;
+  char c = 0;
+  int nEntry = 0;
+
+  /* A column-list is terminated by either a 0x01 or 0x00. */
+  while( 0xFE & (*pEnd | c) ){
+    c = *pEnd++ & 0x80;
+    if( !c ) nEntry++;
+  }
+
+  *ppCollist = pEnd;
+  return nEntry;
+}
+
+/*
+** This function gathers 'y' or 'b' data for a single phrase.
+*/
+static int fts3ExprLHits(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  MatchInfo *p                    /* Matchinfo context */
+){
+  Fts3Table *pTab = (Fts3Table *)p->pCursor->base.pVtab;
+  int iStart;
+  Fts3Phrase *pPhrase = pExpr->pPhrase;
+  char *pIter = pPhrase->doclist.pList;
+  int iCol = 0;
+
+  assert( p->flag==FTS3_MATCHINFO_LHITS_BM || p->flag==FTS3_MATCHINFO_LHITS );
+  if( p->flag==FTS3_MATCHINFO_LHITS ){
+    iStart = pExpr->iPhrase * p->nCol;
+  }else{
+    iStart = pExpr->iPhrase * ((p->nCol + 31) / 32);
+  }
+
+  if( pIter ) while( 1 ){
+    int nHit = fts3ColumnlistCount(&pIter);
+    if( (pPhrase->iColumn>=pTab->nColumn || pPhrase->iColumn==iCol) ){
+      if( p->flag==FTS3_MATCHINFO_LHITS ){
+        p->aMatchinfo[iStart + iCol] = (u32)nHit;
+      }else if( nHit ){
+        p->aMatchinfo[iStart + (iCol+1)/32] |= (1 << (iCol&0x1F));
+      }
+    }
+    assert( *pIter==0x00 || *pIter==0x01 );
+    if( *pIter!=0x01 ) break;
+    pIter++;
+    pIter += fts3GetVarint32(pIter, &iCol);
+    if( iCol>=p->nCol ) return FTS_CORRUPT_VTAB;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Gather the results for matchinfo directives 'y' and 'b'.
+*/
+static int fts3ExprLHitGather(
+  Fts3Expr *pExpr,
+  MatchInfo *p
+){
+  int rc = SQLITE_OK;
+  assert( (pExpr->pLeft==0)==(pExpr->pRight==0) );
+  if( pExpr->bEof==0 && pExpr->iDocid==p->pCursor->iPrevId ){
+    if( pExpr->pLeft ){
+      rc = fts3ExprLHitGather(pExpr->pLeft, p);
+      if( rc==SQLITE_OK ) rc = fts3ExprLHitGather(pExpr->pRight, p);
+    }else{
+      rc = fts3ExprLHits(pExpr, p);
+    }
+  }
+  return rc;
+}
+
+/*
+** sqlite3Fts3ExprIterate() callback used to collect the "global" matchinfo
+** stats for a single query.
+**
+** sqlite3Fts3ExprIterate() callback to load the 'global' elements of a
+** FTS3_MATCHINFO_HITS matchinfo array. The global stats are those elements
+** of the matchinfo array that are constant for all rows returned by the
+** current query.
+**
+** Argument pCtx is actually a pointer to a struct of type MatchInfo. This
+** function populates Matchinfo.aMatchinfo[] as follows:
+**
+**   for(iCol=0; iCol<nCol; iCol++){
+**     aMatchinfo[3*iPhrase*nCol + 3*iCol + 1] = X;
+**     aMatchinfo[3*iPhrase*nCol + 3*iCol + 2] = Y;
+**   }
+**
+** where X is the number of matches for phrase iPhrase is column iCol of all
+** rows of the table. Y is the number of rows for which column iCol contains
+** at least one instance of phrase iPhrase.
+**
+** If the phrase pExpr consists entirely of deferred tokens, then all X and
+** Y values are set to nDoc, where nDoc is the number of documents in the
+** file system. This is done because the full-text index doclist is required
+** to calculate these values properly, and the full-text index doclist is
+** not available for deferred tokens.
+*/
+static int fts3ExprGlobalHitsCb(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  int iPhrase,                    /* Phrase number (numbered from zero) */
+  void *pCtx                      /* Pointer to MatchInfo structure */
+){
+  MatchInfo *p = (MatchInfo *)pCtx;
+  return sqlite3Fts3EvalPhraseStats(
+      p->pCursor, pExpr, &p->aMatchinfo[3*iPhrase*p->nCol]
+  );
+}
+
+/*
+** sqlite3Fts3ExprIterate() callback used to collect the "local" part of the
+** FTS3_MATCHINFO_HITS array. The local stats are those elements of the
+** array that are different for each row returned by the query.
+*/
+static int fts3ExprLocalHitsCb(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  int iPhrase,                    /* Phrase number */
+  void *pCtx                      /* Pointer to MatchInfo structure */
+){
+  int rc = SQLITE_OK;
+  MatchInfo *p = (MatchInfo *)pCtx;
+  int iStart = iPhrase * p->nCol * 3;
+  int i;
+
+  for(i=0; i<p->nCol && rc==SQLITE_OK; i++){
+    char *pCsr;
+    rc = sqlite3Fts3EvalPhrasePoslist(p->pCursor, pExpr, i, &pCsr);
+    if( pCsr ){
+      p->aMatchinfo[iStart+i*3] = fts3ColumnlistCount(&pCsr);
+    }else{
+      p->aMatchinfo[iStart+i*3] = 0;
+    }
+  }
+
+  return rc;
+}
+
+static int fts3MatchinfoCheck(
+  Fts3Table *pTab,
+  char cArg,
+  char **pzErr
+){
+  if( (cArg==FTS3_MATCHINFO_NPHRASE)
+   || (cArg==FTS3_MATCHINFO_NCOL)
+   || (cArg==FTS3_MATCHINFO_NDOC && pTab->bFts4)
+   || (cArg==FTS3_MATCHINFO_AVGLENGTH && pTab->bFts4)
+   || (cArg==FTS3_MATCHINFO_LENGTH && pTab->bHasDocsize)
+   || (cArg==FTS3_MATCHINFO_LCS)
+   || (cArg==FTS3_MATCHINFO_HITS)
+   || (cArg==FTS3_MATCHINFO_LHITS)
+   || (cArg==FTS3_MATCHINFO_LHITS_BM)
+  ){
+    return SQLITE_OK;
+  }
+  sqlite3Fts3ErrMsg(pzErr, "unrecognized matchinfo request: %c", cArg);
+  return SQLITE_ERROR;
+}
+
+static size_t fts3MatchinfoSize(MatchInfo *pInfo, char cArg){
+  size_t nVal;                      /* Number of integers output by cArg */
+
+  switch( cArg ){
+    case FTS3_MATCHINFO_NDOC:
+    case FTS3_MATCHINFO_NPHRASE:
+    case FTS3_MATCHINFO_NCOL:
+      nVal = 1;
+      break;
+
+    case FTS3_MATCHINFO_AVGLENGTH:
+    case FTS3_MATCHINFO_LENGTH:
+    case FTS3_MATCHINFO_LCS:
+      nVal = pInfo->nCol;
+      break;
+
+    case FTS3_MATCHINFO_LHITS:
+      nVal = pInfo->nCol * pInfo->nPhrase;
+      break;
+
+    case FTS3_MATCHINFO_LHITS_BM:
+      nVal = pInfo->nPhrase * ((pInfo->nCol + 31) / 32);
+      break;
+
+    default:
+      assert( cArg==FTS3_MATCHINFO_HITS );
+      nVal = pInfo->nCol * pInfo->nPhrase * 3;
+      break;
+  }
+
+  return nVal;
+}
+
+static int fts3MatchinfoSelectDoctotal(
+  Fts3Table *pTab,
+  sqlite3_stmt **ppStmt,
+  sqlite3_int64 *pnDoc,
+  const char **paLen,
+  const char **ppEnd
+){
+  sqlite3_stmt *pStmt;
+  const char *a;
+  const char *pEnd;
+  sqlite3_int64 nDoc;
+  int n;
+
+
+  if( !*ppStmt ){
+    int rc = sqlite3Fts3SelectDoctotal(pTab, ppStmt);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  pStmt = *ppStmt;
+  assert( sqlite3_data_count(pStmt)==1 );
+
+  n = sqlite3_column_bytes(pStmt, 0);
+  a = sqlite3_column_blob(pStmt, 0);
+  if( a==0 ){
+    return FTS_CORRUPT_VTAB;
+  }
+  pEnd = a + n;
+  a += sqlite3Fts3GetVarintBounded(a, pEnd, &nDoc);
+  if( nDoc<=0 || a>pEnd ){
+    return FTS_CORRUPT_VTAB;
+  }
+  *pnDoc = nDoc;
+
+  if( paLen ) *paLen = a;
+  if( ppEnd ) *ppEnd = pEnd;
+  return SQLITE_OK;
+}
+
+/*
+** An instance of the following structure is used to store state while
+** iterating through a multi-column position-list corresponding to the
+** hits for a single phrase on a single row in order to calculate the
+** values for a matchinfo() FTS3_MATCHINFO_LCS request.
+*/
+typedef struct LcsIterator LcsIterator;
+struct LcsIterator {
+  Fts3Expr *pExpr;                /* Pointer to phrase expression */
+  int iPosOffset;                 /* Tokens count up to end of this phrase */
+  char *pRead;                    /* Cursor used to iterate through aDoclist */
+  int iPos;                       /* Current position */
+};
+
+/*
+** If LcsIterator.iCol is set to the following value, the iterator has
+** finished iterating through all offsets for all columns.
+*/
+#define LCS_ITERATOR_FINISHED 0x7FFFFFFF;
+
+static int fts3MatchinfoLcsCb(
+  Fts3Expr *pExpr,                /* Phrase expression node */
+  int iPhrase,                    /* Phrase number (numbered from zero) */
+  void *pCtx                      /* Pointer to MatchInfo structure */
+){
+  LcsIterator *aIter = (LcsIterator *)pCtx;
+  aIter[iPhrase].pExpr = pExpr;
+  return SQLITE_OK;
+}
+
+/*
+** Advance the iterator passed as an argument to the next position. Return
+** 1 if the iterator is at EOF or if it now points to the start of the
+** position list for the next column.
+*/
+static int fts3LcsIteratorAdvance(LcsIterator *pIter){
+  char *pRead;
+  sqlite3_int64 iRead;
+  int rc = 0;
+
+  if( NEVER(pIter==0) ) return 1;
+  pRead = pIter->pRead;
+  pRead += sqlite3Fts3GetVarint(pRead, &iRead);
+  if( iRead==0 || iRead==1 ){
+    pRead = 0;
+    rc = 1;
+  }else{
+    pIter->iPos += (int)(iRead-2);
+  }
+
+  pIter->pRead = pRead;
+  return rc;
+}
+
+/*
+** This function implements the FTS3_MATCHINFO_LCS matchinfo() flag.
+**
+** If the call is successful, the longest-common-substring lengths for each
+** column are written into the first nCol elements of the pInfo->aMatchinfo[]
+** array before returning. SQLITE_OK is returned in this case.
+**
+** Otherwise, if an error occurs, an SQLite error code is returned and the
+** data written to the first nCol elements of pInfo->aMatchinfo[] is
+** undefined.
+*/
+static int fts3MatchinfoLcs(Fts3Cursor *pCsr, MatchInfo *pInfo){
+  LcsIterator *aIter;
+  int i;
+  int iCol;
+  int nToken = 0;
+  int rc = SQLITE_OK;
+
+  /* Allocate and populate the array of LcsIterator objects. The array
+  ** contains one element for each matchable phrase in the query.
+  **/
+  aIter = sqlite3Fts3MallocZero(sizeof(LcsIterator) * pCsr->nPhrase);
+  if( !aIter ) return SQLITE_NOMEM;
+  (void)sqlite3Fts3ExprIterate(pCsr->pExpr, fts3MatchinfoLcsCb, (void*)aIter);
+
+  for(i=0; i<pInfo->nPhrase; i++){
+    LcsIterator *pIter = &aIter[i];
+    nToken -= pIter->pExpr->pPhrase->nToken;
+    pIter->iPosOffset = nToken;
+  }
+
+  for(iCol=0; iCol<pInfo->nCol; iCol++){
+    int nLcs = 0;                 /* LCS value for this column */
+    int nLive = 0;                /* Number of iterators in aIter not at EOF */
+
+    for(i=0; i<pInfo->nPhrase; i++){
+      LcsIterator *pIt = &aIter[i];
+      rc = sqlite3Fts3EvalPhrasePoslist(pCsr, pIt->pExpr, iCol, &pIt->pRead);
+      if( rc!=SQLITE_OK ) goto matchinfo_lcs_out;
+      if( pIt->pRead ){
+        pIt->iPos = pIt->iPosOffset;
+        fts3LcsIteratorAdvance(pIt);
+        if( pIt->pRead==0 ){
+          rc = FTS_CORRUPT_VTAB;
+          goto matchinfo_lcs_out;
+        }
+        nLive++;
+      }
+    }
+
+    while( nLive>0 ){
+      LcsIterator *pAdv = 0;      /* The iterator to advance by one position */
+      int nThisLcs = 0;           /* LCS for the current iterator positions */
+
+      for(i=0; i<pInfo->nPhrase; i++){
+        LcsIterator *pIter = &aIter[i];
+        if( pIter->pRead==0 ){
+          /* This iterator is already at EOF for this column. */
+          nThisLcs = 0;
+        }else{
+          if( pAdv==0 || pIter->iPos<pAdv->iPos ){
+            pAdv = pIter;
+          }
+          if( nThisLcs==0 || pIter->iPos==pIter[-1].iPos ){
+            nThisLcs++;
+          }else{
+            nThisLcs = 1;
+          }
+          if( nThisLcs>nLcs ) nLcs = nThisLcs;
+        }
+      }
+      if( fts3LcsIteratorAdvance(pAdv) ) nLive--;
+    }
+
+    pInfo->aMatchinfo[iCol] = nLcs;
+  }
+
+ matchinfo_lcs_out:
+  sqlite3_free(aIter);
+  return rc;
+}
+
+/*
+** Populate the buffer pInfo->aMatchinfo[] with an array of integers to
+** be returned by the matchinfo() function. Argument zArg contains the
+** format string passed as the second argument to matchinfo (or the
+** default value "pcx" if no second argument was specified). The format
+** string has already been validated and the pInfo->aMatchinfo[] array
+** is guaranteed to be large enough for the output.
+**
+** If bGlobal is true, then populate all fields of the matchinfo() output.
+** If it is false, then assume that those fields that do not change between
+** rows (i.e. FTS3_MATCHINFO_NPHRASE, NCOL, NDOC, AVGLENGTH and part of HITS)
+** have already been populated.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs. If a value other than SQLITE_OK is returned, the state the
+** pInfo->aMatchinfo[] buffer is left in is undefined.
+*/
+static int fts3MatchinfoValues(
+  Fts3Cursor *pCsr,               /* FTS3 cursor object */
+  int bGlobal,                    /* True to grab the global stats */
+  MatchInfo *pInfo,               /* Matchinfo context object */
+  const char *zArg                /* Matchinfo format string */
+){
+  int rc = SQLITE_OK;
+  int i;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  sqlite3_stmt *pSelect = 0;
+
+  for(i=0; rc==SQLITE_OK && zArg[i]; i++){
+    pInfo->flag = zArg[i];
+    switch( zArg[i] ){
+      case FTS3_MATCHINFO_NPHRASE:
+        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nPhrase;
+        break;
+
+      case FTS3_MATCHINFO_NCOL:
+        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nCol;
+        break;
+
+      case FTS3_MATCHINFO_NDOC:
+        if( bGlobal ){
+          sqlite3_int64 nDoc = 0;
+          rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &nDoc, 0, 0);
+          pInfo->aMatchinfo[0] = (u32)nDoc;
+        }
+        break;
+
+      case FTS3_MATCHINFO_AVGLENGTH:
+        if( bGlobal ){
+          sqlite3_int64 nDoc;     /* Number of rows in table */
+          const char *a;          /* Aggregate column length array */
+          const char *pEnd;       /* First byte past end of length array */
+
+          rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &nDoc, &a, &pEnd);
+          if( rc==SQLITE_OK ){
+            int iCol;
+            for(iCol=0; iCol<pInfo->nCol; iCol++){
+              u32 iVal;
+              sqlite3_int64 nToken;
+              a += sqlite3Fts3GetVarint(a, &nToken);
+              if( a>pEnd ){
+                rc = SQLITE_CORRUPT_VTAB;
+                break;
+              }
+              iVal = (u32)(((u32)(nToken&0xffffffff)+nDoc/2)/nDoc);
+              pInfo->aMatchinfo[iCol] = iVal;
+            }
+          }
+        }
+        break;
+
+      case FTS3_MATCHINFO_LENGTH: {
+        sqlite3_stmt *pSelectDocsize = 0;
+        rc = sqlite3Fts3SelectDocsize(pTab, pCsr->iPrevId, &pSelectDocsize);
+        if( rc==SQLITE_OK ){
+          int iCol;
+          const char *a = sqlite3_column_blob(pSelectDocsize, 0);
+          const char *pEnd = a + sqlite3_column_bytes(pSelectDocsize, 0);
+          for(iCol=0; iCol<pInfo->nCol; iCol++){
+            sqlite3_int64 nToken;
+            a += sqlite3Fts3GetVarintBounded(a, pEnd, &nToken);
+            if( a>pEnd ){
+              rc = SQLITE_CORRUPT_VTAB;
+              break;
+            }
+            pInfo->aMatchinfo[iCol] = (u32)nToken;
+          }
+        }
+        sqlite3_reset(pSelectDocsize);
+        break;
+      }
+
+      case FTS3_MATCHINFO_LCS:
+        rc = fts3ExprLoadDoclists(pCsr, 0, 0);
+        if( rc==SQLITE_OK ){
+          rc = fts3MatchinfoLcs(pCsr, pInfo);
+        }
+        break;
+
+      case FTS3_MATCHINFO_LHITS_BM:
+      case FTS3_MATCHINFO_LHITS: {
+        size_t nZero = fts3MatchinfoSize(pInfo, zArg[i]) * sizeof(u32);
+        memset(pInfo->aMatchinfo, 0, nZero);
+        rc = fts3ExprLHitGather(pCsr->pExpr, pInfo);
+        break;
+      }
+
+      default: {
+        Fts3Expr *pExpr;
+        assert( zArg[i]==FTS3_MATCHINFO_HITS );
+        pExpr = pCsr->pExpr;
+        rc = fts3ExprLoadDoclists(pCsr, 0, 0);
+        if( rc!=SQLITE_OK ) break;
+        if( bGlobal ){
+          if( pCsr->pDeferred ){
+            rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &pInfo->nDoc,0,0);
+            if( rc!=SQLITE_OK ) break;
+          }
+          rc = sqlite3Fts3ExprIterate(pExpr, fts3ExprGlobalHitsCb,(void*)pInfo);
+          sqlite3Fts3EvalTestDeferred(pCsr, &rc);
+          if( rc!=SQLITE_OK ) break;
+        }
+        (void)sqlite3Fts3ExprIterate(pExpr, fts3ExprLocalHitsCb,(void*)pInfo);
+        break;
+      }
+    }
+
+    pInfo->aMatchinfo += fts3MatchinfoSize(pInfo, zArg[i]);
+  }
+
+  sqlite3_reset(pSelect);
+  return rc;
+}
+
+
+/*
+** Populate pCsr->aMatchinfo[] with data for the current row. The
+** 'matchinfo' data is an array of 32-bit unsigned integers (C type u32).
+*/
+static void fts3GetMatchinfo(
+  sqlite3_context *pCtx,        /* Return results here */
+  Fts3Cursor *pCsr,               /* FTS3 Cursor object */
+  const char *zArg                /* Second argument to matchinfo() function */
+){
+  MatchInfo sInfo;
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int bGlobal = 0;                /* Collect 'global' stats as well as local */
+
+  u32 *aOut = 0;
+  void (*xDestroyOut)(void*) = 0;
+
+  memset(&sInfo, 0, sizeof(MatchInfo));
+  sInfo.pCursor = pCsr;
+  sInfo.nCol = pTab->nColumn;
+
+  /* If there is cached matchinfo() data, but the format string for the
+  ** cache does not match the format string for this request, discard
+  ** the cached data. */
+  if( pCsr->pMIBuffer && strcmp(pCsr->pMIBuffer->zMatchinfo, zArg) ){
+    sqlite3Fts3MIBufferFree(pCsr->pMIBuffer);
+    pCsr->pMIBuffer = 0;
+  }
+
+  /* If Fts3Cursor.pMIBuffer is NULL, then this is the first time the
+  ** matchinfo function has been called for this query. In this case
+  ** allocate the array used to accumulate the matchinfo data and
+  ** initialize those elements that are constant for every row.
+  */
+  if( pCsr->pMIBuffer==0 ){
+    size_t nMatchinfo = 0;        /* Number of u32 elements in match-info */
+    int i;                        /* Used to iterate through zArg */
+
+    /* Determine the number of phrases in the query */
+    pCsr->nPhrase = fts3ExprPhraseCount(pCsr->pExpr);
+    sInfo.nPhrase = pCsr->nPhrase;
+
+    /* Determine the number of integers in the buffer returned by this call. */
+    for(i=0; zArg[i]; i++){
+      char *zErr = 0;
+      if( fts3MatchinfoCheck(pTab, zArg[i], &zErr) ){
+        sqlite3_result_error(pCtx, zErr, -1);
+        sqlite3_free(zErr);
+        return;
+      }
+      nMatchinfo += fts3MatchinfoSize(&sInfo, zArg[i]);
+    }
+
+    /* Allocate space for Fts3Cursor.aMatchinfo[] and Fts3Cursor.zMatchinfo. */
+    pCsr->pMIBuffer = fts3MIBufferNew(nMatchinfo, zArg);
+    if( !pCsr->pMIBuffer ) rc = SQLITE_NOMEM;
+
+    pCsr->isMatchinfoNeeded = 1;
+    bGlobal = 1;
+  }
+
+  if( rc==SQLITE_OK ){
+    xDestroyOut = fts3MIBufferAlloc(pCsr->pMIBuffer, &aOut);
+    if( xDestroyOut==0 ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    sInfo.aMatchinfo = aOut;
+    sInfo.nPhrase = pCsr->nPhrase;
+    rc = fts3MatchinfoValues(pCsr, bGlobal, &sInfo, zArg);
+    if( bGlobal ){
+      fts3MIBufferSetGlobal(pCsr->pMIBuffer);
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+    if( xDestroyOut ) xDestroyOut(aOut);
+  }else{
+    int n = pCsr->pMIBuffer->nElem * sizeof(u32);
+    sqlite3_result_blob(pCtx, aOut, n, xDestroyOut);
+  }
+}
+
+/*
+** Implementation of snippet() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3Snippet(
+  sqlite3_context *pCtx,          /* SQLite function call context */
+  Fts3Cursor *pCsr,               /* Cursor object */
+  const char *zStart,             /* Snippet start text - "<b>" */
+  const char *zEnd,               /* Snippet end text - "</b>" */
+  const char *zEllipsis,          /* Snippet ellipsis text - "<b>...</b>" */
+  int iCol,                       /* Extract snippet from this column */
+  int nToken                      /* Approximate number of tokens in snippet */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  int rc = SQLITE_OK;
+  int i;
+  StrBuffer res = {0, 0, 0};
+
+  /* The returned text includes up to four fragments of text extracted from
+  ** the data in the current row. The first iteration of the for(...) loop
+  ** below attempts to locate a single fragment of text nToken tokens in
+  ** size that contains at least one instance of all phrases in the query
+  ** expression that appear in the current row. If such a fragment of text
+  ** cannot be found, the second iteration of the loop attempts to locate
+  ** a pair of fragments, and so on.
+  */
+  int nSnippet = 0;               /* Number of fragments in this snippet */
+  SnippetFragment aSnippet[4];    /* Maximum of 4 fragments per snippet */
+  int nFToken = -1;               /* Number of tokens in each fragment */
+
+  if( !pCsr->pExpr ){
+    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
+    return;
+  }
+
+  /* Limit the snippet length to 64 tokens. */
+  if( nToken<-64 ) nToken = -64;
+  if( nToken>+64 ) nToken = +64;
+
+  for(nSnippet=1; 1; nSnippet++){
+
+    int iSnip;                    /* Loop counter 0..nSnippet-1 */
+    u64 mCovered = 0;             /* Bitmask of phrases covered by snippet */
+    u64 mSeen = 0;                /* Bitmask of phrases seen by BestSnippet() */
+
+    if( nToken>=0 ){
+      nFToken = (nToken+nSnippet-1) / nSnippet;
+    }else{
+      nFToken = -1 * nToken;
+    }
+
+    for(iSnip=0; iSnip<nSnippet; iSnip++){
+      int iBestScore = -1;        /* Best score of columns checked so far */
+      int iRead;                  /* Used to iterate through columns */
+      SnippetFragment *pFragment = &aSnippet[iSnip];
+
+      memset(pFragment, 0, sizeof(*pFragment));
+
+      /* Loop through all columns of the table being considered for snippets.
+      ** If the iCol argument to this function was negative, this means all
+      ** columns of the FTS3 table. Otherwise, only column iCol is considered.
+      */
+      for(iRead=0; iRead<pTab->nColumn; iRead++){
+        SnippetFragment sF = {0, 0, 0, 0};
+        int iS = 0;
+        if( iCol>=0 && iRead!=iCol ) continue;
+
+        /* Find the best snippet of nFToken tokens in column iRead. */
+        rc = fts3BestSnippet(nFToken, pCsr, iRead, mCovered, &mSeen, &sF, &iS);
+        if( rc!=SQLITE_OK ){
+          goto snippet_out;
+        }
+        if( iS>iBestScore ){
+          *pFragment = sF;
+          iBestScore = iS;
+        }
+      }
+
+      mCovered |= pFragment->covered;
+    }
+
+    /* If all query phrases seen by fts3BestSnippet() are present in at least
+    ** one of the nSnippet snippet fragments, break out of the loop.
+    */
+    assert( (mCovered&mSeen)==mCovered );
+    if( mSeen==mCovered || nSnippet==SizeofArray(aSnippet) ) break;
+  }
+
+  assert( nFToken>0 );
+
+  for(i=0; i<nSnippet && rc==SQLITE_OK; i++){
+    rc = fts3SnippetText(pCsr, &aSnippet[i],
+        i, (i==nSnippet-1), nFToken, zStart, zEnd, zEllipsis, &res
+    );
+  }
+
+ snippet_out:
+  sqlite3Fts3SegmentsClose(pTab);
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+    sqlite3_free(res.z);
+  }else{
+    sqlite3_result_text(pCtx, res.z, -1, sqlite3_free);
+  }
+}
+
+
+typedef struct TermOffset TermOffset;
+typedef struct TermOffsetCtx TermOffsetCtx;
+
+struct TermOffset {
+  char *pList;                    /* Position-list */
+  i64 iPos;                       /* Position just read from pList */
+  i64 iOff;                       /* Offset of this term from read positions */
+};
+
+struct TermOffsetCtx {
+  Fts3Cursor *pCsr;
+  int iCol;                       /* Column of table to populate aTerm for */
+  int iTerm;
+  sqlite3_int64 iDocid;
+  TermOffset *aTerm;
+};
+
+/*
+** This function is an sqlite3Fts3ExprIterate() callback used by sqlite3Fts3Offsets().
+*/
+static int fts3ExprTermOffsetInit(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  TermOffsetCtx *p = (TermOffsetCtx *)ctx;
+  int nTerm;                      /* Number of tokens in phrase */
+  int iTerm;                      /* For looping through nTerm phrase terms */
+  char *pList;                    /* Pointer to position list for phrase */
+  i64 iPos = 0;                   /* First position in position-list */
+  int rc;
+
+  UNUSED_PARAMETER(iPhrase);
+  rc = sqlite3Fts3EvalPhrasePoslist(p->pCsr, pExpr, p->iCol, &pList);
+  nTerm = pExpr->pPhrase->nToken;
+  if( pList ){
+    fts3GetDeltaPosition(&pList, &iPos);
+    assert_fts3_nc( iPos>=0 );
+  }
+
+  for(iTerm=0; iTerm<nTerm; iTerm++){
+    TermOffset *pT = &p->aTerm[p->iTerm++];
+    pT->iOff = nTerm-iTerm-1;
+    pT->pList = pList;
+    pT->iPos = iPos;
+  }
+
+  return rc;
+}
+
+/*
+** If expression pExpr is a phrase expression that uses an MSR query,
+** restart it as a regular, non-incremental query. Return SQLITE_OK
+** if successful, or an SQLite error code otherwise.
+*/
+static int fts3ExprRestartIfCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
+  TermOffsetCtx *p = (TermOffsetCtx*)ctx;
+  int rc = SQLITE_OK;
+  UNUSED_PARAMETER(iPhrase);
+  if( pExpr->pPhrase && pExpr->pPhrase->bIncr ){
+    rc = sqlite3Fts3MsrCancel(p->pCsr, pExpr);
+    pExpr->pPhrase->bIncr = 0;
+  }
+  return rc;
+}
+
+/*
+** Implementation of offsets() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3Offsets(
+  sqlite3_context *pCtx,          /* SQLite function call context */
+  Fts3Cursor *pCsr                /* Cursor object */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  sqlite3_tokenizer_module const *pMod = pTab->pTokenizer->pModule;
+  int rc;                         /* Return Code */
+  int nToken;                     /* Number of tokens in query */
+  int iCol;                       /* Column currently being processed */
+  StrBuffer res = {0, 0, 0};      /* Result string */
+  TermOffsetCtx sCtx;             /* Context for fts3ExprTermOffsetInit() */
+
+  if( !pCsr->pExpr ){
+    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
+    return;
+  }
+
+  memset(&sCtx, 0, sizeof(sCtx));
+  assert( pCsr->isRequireSeek==0 );
+
+  /* Count the number of terms in the query */
+  rc = fts3ExprLoadDoclists(pCsr, 0, &nToken);
+  if( rc!=SQLITE_OK ) goto offsets_out;
+
+  /* Allocate the array of TermOffset iterators. */
+  sCtx.aTerm = (TermOffset *)sqlite3Fts3MallocZero(sizeof(TermOffset)*nToken);
+  if( 0==sCtx.aTerm ){
+    rc = SQLITE_NOMEM;
+    goto offsets_out;
+  }
+  sCtx.iDocid = pCsr->iPrevId;
+  sCtx.pCsr = pCsr;
+
+  /* If a query restart will be required, do it here, rather than later of
+  ** after pointers to poslist buffers that may be invalidated by a restart
+  ** have been saved.  */
+  rc = sqlite3Fts3ExprIterate(pCsr->pExpr, fts3ExprRestartIfCb, (void*)&sCtx);
+  if( rc!=SQLITE_OK ) goto offsets_out;
+
+  /* Loop through the table columns, appending offset information to
+  ** string-buffer res for each column.
+  */
+  for(iCol=0; iCol<pTab->nColumn; iCol++){
+    sqlite3_tokenizer_cursor *pC; /* Tokenizer cursor */
+    const char *ZDUMMY;           /* Dummy argument used with xNext() */
+    int NDUMMY = 0;               /* Dummy argument used with xNext() */
+    int iStart = 0;
+    int iEnd = 0;
+    int iCurrent = 0;
+    const char *zDoc;
+    int nDoc;
+
+    /* Initialize the contents of sCtx.aTerm[] for column iCol. This
+    ** operation may fail if the database contains corrupt records.
+    */
+    sCtx.iCol = iCol;
+    sCtx.iTerm = 0;
+    rc = sqlite3Fts3ExprIterate(
+        pCsr->pExpr, fts3ExprTermOffsetInit, (void*)&sCtx
+    );
+    if( rc!=SQLITE_OK ) goto offsets_out;
+
+    /* Retreive the text stored in column iCol. If an SQL NULL is stored
+    ** in column iCol, jump immediately to the next iteration of the loop.
+    ** If an OOM occurs while retrieving the data (this can happen if SQLite
+    ** needs to transform the data from utf-16 to utf-8), return SQLITE_NOMEM
+    ** to the caller.
+    */
+    zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol+1);
+    nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol+1);
+    if( zDoc==0 ){
+      if( sqlite3_column_type(pCsr->pStmt, iCol+1)==SQLITE_NULL ){
+        continue;
+      }
+      rc = SQLITE_NOMEM;
+      goto offsets_out;
+    }
+
+    /* Initialize a tokenizer iterator to iterate through column iCol. */
+    rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, pCsr->iLangid,
+        zDoc, nDoc, &pC
+    );
+    if( rc!=SQLITE_OK ) goto offsets_out;
+
+    rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
+    while( rc==SQLITE_OK ){
+      int i;                      /* Used to loop through terms */
+      int iMinPos = 0x7FFFFFFF;   /* Position of next token */
+      TermOffset *pTerm = 0;      /* TermOffset associated with next token */
+
+      for(i=0; i<nToken; i++){
+        TermOffset *pT = &sCtx.aTerm[i];
+        if( pT->pList && (pT->iPos-pT->iOff)<iMinPos ){
+          iMinPos = pT->iPos-pT->iOff;
+          pTerm = pT;
+        }
+      }
+
+      if( !pTerm ){
+        /* All offsets for this column have been gathered. */
+        rc = SQLITE_DONE;
+      }else{
+        assert_fts3_nc( iCurrent<=iMinPos );
+        if( 0==(0xFE&*pTerm->pList) ){
+          pTerm->pList = 0;
+        }else{
+          fts3GetDeltaPosition(&pTerm->pList, &pTerm->iPos);
+        }
+        while( rc==SQLITE_OK && iCurrent<iMinPos ){
+          rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
+        }
+        if( rc==SQLITE_OK ){
+          char aBuffer[64];
+          sqlite3_snprintf(sizeof(aBuffer), aBuffer,
+              "%d %d %d %d ", iCol, pTerm-sCtx.aTerm, iStart, iEnd-iStart
+          );
+          rc = fts3StringAppend(&res, aBuffer, -1);
+        }else if( rc==SQLITE_DONE && pTab->zContentTbl==0 ){
+          rc = FTS_CORRUPT_VTAB;
+        }
+      }
+    }
+    if( rc==SQLITE_DONE ){
+      rc = SQLITE_OK;
+    }
+
+    pMod->xClose(pC);
+    if( rc!=SQLITE_OK ) goto offsets_out;
+  }
+
+ offsets_out:
+  sqlite3_free(sCtx.aTerm);
+  assert( rc!=SQLITE_DONE );
+  sqlite3Fts3SegmentsClose(pTab);
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx,  rc);
+    sqlite3_free(res.z);
+  }else{
+    sqlite3_result_text(pCtx, res.z, res.n-1, sqlite3_free);
+  }
+  return;
+}
+
+/*
+** Implementation of matchinfo() function.
+*/
+SQLITE_PRIVATE void sqlite3Fts3Matchinfo(
+  sqlite3_context *pContext,      /* Function call context */
+  Fts3Cursor *pCsr,               /* FTS3 table cursor */
+  const char *zArg                /* Second arg to matchinfo() function */
+){
+  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
+  const char *zFormat;
+
+  if( zArg ){
+    zFormat = zArg;
+  }else{
+    zFormat = FTS3_MATCHINFO_DEFAULT;
+  }
+
+  if( !pCsr->pExpr ){
+    sqlite3_result_blob(pContext, "", 0, SQLITE_STATIC);
+    return;
+  }else{
+    /* Retrieve matchinfo() data. */
+    fts3GetMatchinfo(pContext, pCsr, zFormat);
+    sqlite3Fts3SegmentsClose(pTab);
+  }
+}
+
+#endif
+
+/************** End of fts3_snippet.c ****************************************/
+/************** Begin file fts3_unicode.c ************************************/
+/*
+** 2012 May 24
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Implementation of the "unicode" full-text-search tokenizer.
+*/
+
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+/* #include <stdio.h> */
+/* #include <string.h> */
+
+/* #include "fts3_tokenizer.h" */
+
+/*
+** The following two macros - READ_UTF8 and WRITE_UTF8 - have been copied
+** from the sqlite3 source file utf.c. If this file is compiled as part
+** of the amalgamation, they are not required.
+*/
+#ifndef SQLITE_AMALGAMATION
+
+static const unsigned char sqlite3Utf8Trans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+#define READ_UTF8(zIn, zTerm, c)                           \
+  c = *(zIn++);                                            \
+  if( c>=0xc0 ){                                           \
+    c = sqlite3Utf8Trans1[c-0xc0];                         \
+    while( zIn!=zTerm && (*zIn & 0xc0)==0x80 ){            \
+      c = (c<<6) + (0x3f & *(zIn++));                      \
+    }                                                      \
+    if( c<0x80                                             \
+        || (c&0xFFFFF800)==0xD800                          \
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }        \
+  }
+
+#define WRITE_UTF8(zOut, c) {                          \
+  if( c<0x00080 ){                                     \
+    *zOut++ = (u8)(c&0xFF);                            \
+  }                                                    \
+  else if( c<0x00800 ){                                \
+    *zOut++ = 0xC0 + (u8)((c>>6)&0x1F);                \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+  else if( c<0x10000 ){                                \
+    *zOut++ = 0xE0 + (u8)((c>>12)&0x0F);               \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }else{                                               \
+    *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);             \
+    *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);             \
+    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
+    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
+  }                                                    \
+}
+
+#endif /* ifndef SQLITE_AMALGAMATION */
+
+typedef struct unicode_tokenizer unicode_tokenizer;
+typedef struct unicode_cursor unicode_cursor;
+
+struct unicode_tokenizer {
+  sqlite3_tokenizer base;
+  int eRemoveDiacritic;
+  int nException;
+  int *aiException;
+};
+
+struct unicode_cursor {
+  sqlite3_tokenizer_cursor base;
+  const unsigned char *aInput;    /* Input text being tokenized */
+  int nInput;                     /* Size of aInput[] in bytes */
+  int iOff;                       /* Current offset within aInput[] */
+  int iToken;                     /* Index of next token to be returned */
+  char *zToken;                   /* storage for current token */
+  int nAlloc;                     /* space allocated at zToken */
+};
+
+
+/*
+** Destroy a tokenizer allocated by unicodeCreate().
+*/
+static int unicodeDestroy(sqlite3_tokenizer *pTokenizer){
+  if( pTokenizer ){
+    unicode_tokenizer *p = (unicode_tokenizer *)pTokenizer;
+    sqlite3_free(p->aiException);
+    sqlite3_free(p);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** As part of a tokenchars= or separators= option, the CREATE VIRTUAL TABLE
+** statement has specified that the tokenizer for this table shall consider
+** all characters in string zIn/nIn to be separators (if bAlnum==0) or
+** token characters (if bAlnum==1).
+**
+** For each codepoint in the zIn/nIn string, this function checks if the
+** sqlite3FtsUnicodeIsalnum() function already returns the desired result.
+** If so, no action is taken. Otherwise, the codepoint is added to the
+** unicode_tokenizer.aiException[] array. For the purposes of tokenization,
+** the return value of sqlite3FtsUnicodeIsalnum() is inverted for all
+** codepoints in the aiException[] array.
+**
+** If a standalone diacritic mark (one that sqlite3FtsUnicodeIsdiacritic()
+** identifies as a diacritic) occurs in the zIn/nIn string it is ignored.
+** It is not possible to change the behavior of the tokenizer with respect
+** to these codepoints.
+*/
+static int unicodeAddExceptions(
+  unicode_tokenizer *p,           /* Tokenizer to add exceptions to */
+  int bAlnum,                     /* Replace Isalnum() return value with this */
+  const char *zIn,                /* Array of characters to make exceptions */
+  int nIn                         /* Length of z in bytes */
+){
+  const unsigned char *z = (const unsigned char *)zIn;
+  const unsigned char *zTerm = &z[nIn];
+  unsigned int iCode;
+  int nEntry = 0;
+
+  assert( bAlnum==0 || bAlnum==1 );
+
+  while( z<zTerm ){
+    READ_UTF8(z, zTerm, iCode);
+    assert( (sqlite3FtsUnicodeIsalnum((int)iCode) & 0xFFFFFFFE)==0 );
+    if( sqlite3FtsUnicodeIsalnum((int)iCode)!=bAlnum
+     && sqlite3FtsUnicodeIsdiacritic((int)iCode)==0
+    ){
+      nEntry++;
+    }
+  }
+
+  if( nEntry ){
+    int *aNew;                    /* New aiException[] array */
+    int nNew;                     /* Number of valid entries in array aNew[] */
+
+    aNew = sqlite3_realloc64(p->aiException,(p->nException+nEntry)*sizeof(int));
+    if( aNew==0 ) return SQLITE_NOMEM;
+    nNew = p->nException;
+
+    z = (const unsigned char *)zIn;
+    while( z<zTerm ){
+      READ_UTF8(z, zTerm, iCode);
+      if( sqlite3FtsUnicodeIsalnum((int)iCode)!=bAlnum
+       && sqlite3FtsUnicodeIsdiacritic((int)iCode)==0
+      ){
+        int i, j;
+        for(i=0; i<nNew && aNew[i]<(int)iCode; i++);
+        for(j=nNew; j>i; j--) aNew[j] = aNew[j-1];
+        aNew[i] = (int)iCode;
+        nNew++;
+      }
+    }
+    p->aiException = aNew;
+    p->nException = nNew;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Return true if the p->aiException[] array contains the value iCode.
+*/
+static int unicodeIsException(unicode_tokenizer *p, int iCode){
+  if( p->nException>0 ){
+    int *a = p->aiException;
+    int iLo = 0;
+    int iHi = p->nException-1;
+
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      if( iCode==a[iTest] ){
+        return 1;
+      }else if( iCode>a[iTest] ){
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Return true if, for the purposes of tokenization, codepoint iCode is
+** considered a token character (not a separator).
+*/
+static int unicodeIsAlnum(unicode_tokenizer *p, int iCode){
+  assert( (sqlite3FtsUnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 );
+  return sqlite3FtsUnicodeIsalnum(iCode) ^ unicodeIsException(p, iCode);
+}
+
+/*
+** Create a new tokenizer instance.
+*/
+static int unicodeCreate(
+  int nArg,                       /* Size of array argv[] */
+  const char * const *azArg,      /* Tokenizer creation arguments */
+  sqlite3_tokenizer **pp          /* OUT: New tokenizer handle */
+){
+  unicode_tokenizer *pNew;        /* New tokenizer object */
+  int i;
+  int rc = SQLITE_OK;
+
+  pNew = (unicode_tokenizer *) sqlite3_malloc(sizeof(unicode_tokenizer));
+  if( pNew==NULL ) return SQLITE_NOMEM;
+  memset(pNew, 0, sizeof(unicode_tokenizer));
+  pNew->eRemoveDiacritic = 1;
+
+  for(i=0; rc==SQLITE_OK && i<nArg; i++){
+    const char *z = azArg[i];
+    int n = (int)strlen(z);
+
+    if( n==19 && memcmp("remove_diacritics=1", z, 19)==0 ){
+      pNew->eRemoveDiacritic = 1;
+    }
+    else if( n==19 && memcmp("remove_diacritics=0", z, 19)==0 ){
+      pNew->eRemoveDiacritic = 0;
+    }
+    else if( n==19 && memcmp("remove_diacritics=2", z, 19)==0 ){
+      pNew->eRemoveDiacritic = 2;
+    }
+    else if( n>=11 && memcmp("tokenchars=", z, 11)==0 ){
+      rc = unicodeAddExceptions(pNew, 1, &z[11], n-11);
+    }
+    else if( n>=11 && memcmp("separators=", z, 11)==0 ){
+      rc = unicodeAddExceptions(pNew, 0, &z[11], n-11);
+    }
+    else{
+      /* Unrecognized argument */
+      rc  = SQLITE_ERROR;
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    unicodeDestroy((sqlite3_tokenizer *)pNew);
+    pNew = 0;
+  }
+  *pp = (sqlite3_tokenizer *)pNew;
+  return rc;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is pInput[0..nBytes-1].  A cursor
+** used to incrementally tokenize this string is returned in
+** *ppCursor.
+*/
+static int unicodeOpen(
+  sqlite3_tokenizer *p,           /* The tokenizer */
+  const char *aInput,             /* Input string */
+  int nInput,                     /* Size of string aInput in bytes */
+  sqlite3_tokenizer_cursor **pp   /* OUT: New cursor object */
+){
+  unicode_cursor *pCsr;
+
+  pCsr = (unicode_cursor *)sqlite3_malloc(sizeof(unicode_cursor));
+  if( pCsr==0 ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(unicode_cursor));
+
+  pCsr->aInput = (const unsigned char *)aInput;
+  if( aInput==0 ){
+    pCsr->nInput = 0;
+    pCsr->aInput = (const unsigned char*)"";
+  }else if( nInput<0 ){
+    pCsr->nInput = (int)strlen(aInput);
+  }else{
+    pCsr->nInput = nInput;
+  }
+
+  *pp = &pCsr->base;
+  UNUSED_PARAMETER(p);
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to
+** simpleOpen() above.
+*/
+static int unicodeClose(sqlite3_tokenizer_cursor *pCursor){
+  unicode_cursor *pCsr = (unicode_cursor *) pCursor;
+  sqlite3_free(pCsr->zToken);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** Extract the next token from a tokenization cursor.  The cursor must
+** have been opened by a prior call to simpleOpen().
+*/
+static int unicodeNext(
+  sqlite3_tokenizer_cursor *pC,   /* Cursor returned by simpleOpen */
+  const char **paToken,           /* OUT: Token text */
+  int *pnToken,                   /* OUT: Number of bytes at *paToken */
+  int *piStart,                   /* OUT: Starting offset of token */
+  int *piEnd,                     /* OUT: Ending offset of token */
+  int *piPos                      /* OUT: Position integer of token */
+){
+  unicode_cursor *pCsr = (unicode_cursor *)pC;
+  unicode_tokenizer *p = ((unicode_tokenizer *)pCsr->base.pTokenizer);
+  unsigned int iCode = 0;
+  char *zOut;
+  const unsigned char *z = &pCsr->aInput[pCsr->iOff];
+  const unsigned char *zStart = z;
+  const unsigned char *zEnd;
+  const unsigned char *zTerm = &pCsr->aInput[pCsr->nInput];
+
+  /* Scan past any delimiter characters before the start of the next token.
+  ** Return SQLITE_DONE early if this takes us all the way to the end of
+  ** the input.  */
+  while( z<zTerm ){
+    READ_UTF8(z, zTerm, iCode);
+    if( unicodeIsAlnum(p, (int)iCode) ) break;
+    zStart = z;
+  }
+  if( zStart>=zTerm ) return SQLITE_DONE;
+
+  zOut = pCsr->zToken;
+  do {
+    int iOut;
+
+    /* Grow the output buffer if required. */
+    if( (zOut-pCsr->zToken)>=(pCsr->nAlloc-4) ){
+      char *zNew = sqlite3_realloc64(pCsr->zToken, pCsr->nAlloc+64);
+      if( !zNew ) return SQLITE_NOMEM;
+      zOut = &zNew[zOut - pCsr->zToken];
+      pCsr->zToken = zNew;
+      pCsr->nAlloc += 64;
+    }
+
+    /* Write the folded case of the last character read to the output */
+    zEnd = z;
+    iOut = sqlite3FtsUnicodeFold((int)iCode, p->eRemoveDiacritic);
+    if( iOut ){
+      WRITE_UTF8(zOut, iOut);
+    }
+
+    /* If the cursor is not at EOF, read the next character */
+    if( z>=zTerm ) break;
+    READ_UTF8(z, zTerm, iCode);
+  }while( unicodeIsAlnum(p, (int)iCode)
+       || sqlite3FtsUnicodeIsdiacritic((int)iCode)
+  );
+
+  /* Set the output variables and return. */
+  pCsr->iOff = (int)(z - pCsr->aInput);
+  *paToken = pCsr->zToken;
+  *pnToken = (int)(zOut - pCsr->zToken);
+  *piStart = (int)(zStart - pCsr->aInput);
+  *piEnd = (int)(zEnd - pCsr->aInput);
+  *piPos = pCsr->iToken++;
+  return SQLITE_OK;
+}
+
+/*
+** Set *ppModule to a pointer to the sqlite3_tokenizer_module
+** structure for the unicode tokenizer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const **ppModule){
+  static const sqlite3_tokenizer_module module = {
+    0,
+    unicodeCreate,
+    unicodeDestroy,
+    unicodeOpen,
+    unicodeClose,
+    unicodeNext,
+    0,
+  };
+  *ppModule = &module;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+#endif /* ifndef SQLITE_DISABLE_FTS3_UNICODE */
+
+/************** End of fts3_unicode.c ****************************************/
+/************** Begin file fts3_unicode2.c ***********************************/
+/*
+** 2012-05-25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+/*
+** DO NOT EDIT THIS MACHINE GENERATED FILE.
+*/
+
+#ifndef SQLITE_DISABLE_FTS3_UNICODE
+#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
+
+/* #include <assert.h> */
+
+/*
+** Return true if the argument corresponds to a unicode codepoint
+** classified as either a letter or a number. Otherwise false.
+**
+** The results are undefined if the value passed to this function
+** is less than zero.
+*/
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsalnum(int c){
+  /* Each unsigned integer in the following array corresponds to a contiguous
+  ** range of unicode codepoints that are not either letters or numbers (i.e.
+  ** codepoints for which this function should return 0).
+  **
+  ** The most significant 22 bits in each 32-bit value contain the first
+  ** codepoint in the range. The least significant 10 bits are used to store
+  ** the size of the range (always at least 1). In other words, the value
+  ** ((C<<22) + N) represents a range of N codepoints starting with codepoint
+  ** C. It is not possible to represent a range larger than 1023 codepoints
+  ** using this format.
+  */
+  static const unsigned int aEntry[] = {
+    0x00000030, 0x0000E807, 0x00016C06, 0x0001EC2F, 0x0002AC07,
+    0x0002D001, 0x0002D803, 0x0002EC01, 0x0002FC01, 0x00035C01,
+    0x0003DC01, 0x000B0804, 0x000B480E, 0x000B9407, 0x000BB401,
+    0x000BBC81, 0x000DD401, 0x000DF801, 0x000E1002, 0x000E1C01,
+    0x000FD801, 0x00120808, 0x00156806, 0x00162402, 0x00163C01,
+    0x00164437, 0x0017CC02, 0x00180005, 0x00181816, 0x00187802,
+    0x00192C15, 0x0019A804, 0x0019C001, 0x001B5001, 0x001B580F,
+    0x001B9C07, 0x001BF402, 0x001C000E, 0x001C3C01, 0x001C4401,
+    0x001CC01B, 0x001E980B, 0x001FAC09, 0x001FD804, 0x00205804,
+    0x00206C09, 0x00209403, 0x0020A405, 0x0020C00F, 0x00216403,
+    0x00217801, 0x0023901B, 0x00240004, 0x0024E803, 0x0024F812,
+    0x00254407, 0x00258804, 0x0025C001, 0x00260403, 0x0026F001,
+    0x0026F807, 0x00271C02, 0x00272C03, 0x00275C01, 0x00278802,
+    0x0027C802, 0x0027E802, 0x00280403, 0x0028F001, 0x0028F805,
+    0x00291C02, 0x00292C03, 0x00294401, 0x0029C002, 0x0029D401,
+    0x002A0403, 0x002AF001, 0x002AF808, 0x002B1C03, 0x002B2C03,
+    0x002B8802, 0x002BC002, 0x002C0403, 0x002CF001, 0x002CF807,
+    0x002D1C02, 0x002D2C03, 0x002D5802, 0x002D8802, 0x002DC001,
+    0x002E0801, 0x002EF805, 0x002F1803, 0x002F2804, 0x002F5C01,
+    0x002FCC08, 0x00300403, 0x0030F807, 0x00311803, 0x00312804,
+    0x00315402, 0x00318802, 0x0031FC01, 0x00320802, 0x0032F001,
+    0x0032F807, 0x00331803, 0x00332804, 0x00335402, 0x00338802,
+    0x00340802, 0x0034F807, 0x00351803, 0x00352804, 0x00355C01,
+    0x00358802, 0x0035E401, 0x00360802, 0x00372801, 0x00373C06,
+    0x00375801, 0x00376008, 0x0037C803, 0x0038C401, 0x0038D007,
+    0x0038FC01, 0x00391C09, 0x00396802, 0x003AC401, 0x003AD006,
+    0x003AEC02, 0x003B2006, 0x003C041F, 0x003CD00C, 0x003DC417,
+    0x003E340B, 0x003E6424, 0x003EF80F, 0x003F380D, 0x0040AC14,
+    0x00412806, 0x00415804, 0x00417803, 0x00418803, 0x00419C07,
+    0x0041C404, 0x0042080C, 0x00423C01, 0x00426806, 0x0043EC01,
+    0x004D740C, 0x004E400A, 0x00500001, 0x0059B402, 0x005A0001,
+    0x005A6C02, 0x005BAC03, 0x005C4803, 0x005CC805, 0x005D4802,
+    0x005DC802, 0x005ED023, 0x005F6004, 0x005F7401, 0x0060000F,
+    0x0062A401, 0x0064800C, 0x0064C00C, 0x00650001, 0x00651002,
+    0x0066C011, 0x00672002, 0x00677822, 0x00685C05, 0x00687802,
+    0x0069540A, 0x0069801D, 0x0069FC01, 0x006A8007, 0x006AA006,
+    0x006C0005, 0x006CD011, 0x006D6823, 0x006E0003, 0x006E840D,
+    0x006F980E, 0x006FF004, 0x00709014, 0x0070EC05, 0x0071F802,
+    0x00730008, 0x00734019, 0x0073B401, 0x0073C803, 0x00770027,
+    0x0077F004, 0x007EF401, 0x007EFC03, 0x007F3403, 0x007F7403,
+    0x007FB403, 0x007FF402, 0x00800065, 0x0081A806, 0x0081E805,
+    0x00822805, 0x0082801A, 0x00834021, 0x00840002, 0x00840C04,
+    0x00842002, 0x00845001, 0x00845803, 0x00847806, 0x00849401,
+    0x00849C01, 0x0084A401, 0x0084B801, 0x0084E802, 0x00850005,
+    0x00852804, 0x00853C01, 0x00864264, 0x00900027, 0x0091000B,
+    0x0092704E, 0x00940200, 0x009C0475, 0x009E53B9, 0x00AD400A,
+    0x00B39406, 0x00B3BC03, 0x00B3E404, 0x00B3F802, 0x00B5C001,
+    0x00B5FC01, 0x00B7804F, 0x00B8C00C, 0x00BA001A, 0x00BA6C59,
+    0x00BC00D6, 0x00BFC00C, 0x00C00005, 0x00C02019, 0x00C0A807,
+    0x00C0D802, 0x00C0F403, 0x00C26404, 0x00C28001, 0x00C3EC01,
+    0x00C64002, 0x00C6580A, 0x00C70024, 0x00C8001F, 0x00C8A81E,
+    0x00C94001, 0x00C98020, 0x00CA2827, 0x00CB003F, 0x00CC0100,
+    0x01370040, 0x02924037, 0x0293F802, 0x02983403, 0x0299BC10,
+    0x029A7C01, 0x029BC008, 0x029C0017, 0x029C8002, 0x029E2402,
+    0x02A00801, 0x02A01801, 0x02A02C01, 0x02A08C09, 0x02A0D804,
+    0x02A1D004, 0x02A20002, 0x02A2D011, 0x02A33802, 0x02A38012,
+    0x02A3E003, 0x02A4980A, 0x02A51C0D, 0x02A57C01, 0x02A60004,
+    0x02A6CC1B, 0x02A77802, 0x02A8A40E, 0x02A90C01, 0x02A93002,
+    0x02A97004, 0x02A9DC03, 0x02A9EC01, 0x02AAC001, 0x02AAC803,
+    0x02AADC02, 0x02AAF802, 0x02AB0401, 0x02AB7802, 0x02ABAC07,
+    0x02ABD402, 0x02AF8C0B, 0x03600001, 0x036DFC02, 0x036FFC02,
+    0x037FFC01, 0x03EC7801, 0x03ECA401, 0x03EEC810, 0x03F4F802,
+    0x03F7F002, 0x03F8001A, 0x03F88007, 0x03F8C023, 0x03F95013,
+    0x03F9A004, 0x03FBFC01, 0x03FC040F, 0x03FC6807, 0x03FCEC06,
+    0x03FD6C0B, 0x03FF8007, 0x03FFA007, 0x03FFE405, 0x04040003,
+    0x0404DC09, 0x0405E411, 0x0406400C, 0x0407402E, 0x040E7C01,
+    0x040F4001, 0x04215C01, 0x04247C01, 0x0424FC01, 0x04280403,
+    0x04281402, 0x04283004, 0x0428E003, 0x0428FC01, 0x04294009,
+    0x0429FC01, 0x042CE407, 0x04400003, 0x0440E016, 0x04420003,
+    0x0442C012, 0x04440003, 0x04449C0E, 0x04450004, 0x04460003,
+    0x0446CC0E, 0x04471404, 0x045AAC0D, 0x0491C004, 0x05BD442E,
+    0x05BE3C04, 0x074000F6, 0x07440027, 0x0744A4B5, 0x07480046,
+    0x074C0057, 0x075B0401, 0x075B6C01, 0x075BEC01, 0x075C5401,
+    0x075CD401, 0x075D3C01, 0x075DBC01, 0x075E2401, 0x075EA401,
+    0x075F0C01, 0x07BBC002, 0x07C0002C, 0x07C0C064, 0x07C2800F,
+    0x07C2C40E, 0x07C3040F, 0x07C3440F, 0x07C4401F, 0x07C4C03C,
+    0x07C5C02B, 0x07C7981D, 0x07C8402B, 0x07C90009, 0x07C94002,
+    0x07CC0021, 0x07CCC006, 0x07CCDC46, 0x07CE0014, 0x07CE8025,
+    0x07CF1805, 0x07CF8011, 0x07D0003F, 0x07D10001, 0x07D108B6,
+    0x07D3E404, 0x07D4003E, 0x07D50004, 0x07D54018, 0x07D7EC46,
+    0x07D9140B, 0x07DA0046, 0x07DC0074, 0x38000401, 0x38008060,
+    0x380400F0,
+  };
+  static const unsigned int aAscii[4] = {
+    0xFFFFFFFF, 0xFC00FFFF, 0xF8000001, 0xF8000001,
+  };
+
+  if( (unsigned int)c<128 ){
+    return ( (aAscii[c >> 5] & ((unsigned int)1 << (c & 0x001F)))==0 );
+  }else if( (unsigned int)c<(1<<22) ){
+    unsigned int key = (((unsigned int)c)<<10) | 0x000003FF;
+    int iRes = 0;
+    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
+    int iLo = 0;
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      if( key >= aEntry[iTest] ){
+        iRes = iTest;
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+    assert( aEntry[0]<key );
+    assert( key>=aEntry[iRes] );
+    return (((unsigned int)c) >= ((aEntry[iRes]>>10) + (aEntry[iRes]&0x3FF)));
+  }
+  return 1;
+}
+
+
+/*
+** If the argument is a codepoint corresponding to a lowercase letter
+** in the ASCII range with a diacritic added, return the codepoint
+** of the ASCII letter only. For example, if passed 235 - "LATIN
+** SMALL LETTER E WITH DIAERESIS" - return 65 ("LATIN SMALL LETTER
+** E"). The resuls of passing a codepoint that corresponds to an
+** uppercase letter are undefined.
+*/
+static int remove_diacritic(int c, int bComplex){
+  unsigned short aDia[] = {
+        0,  1797,  1848,  1859,  1891,  1928,  1940,  1995,
+     2024,  2040,  2060,  2110,  2168,  2206,  2264,  2286,
+     2344,  2383,  2472,  2488,  2516,  2596,  2668,  2732,
+     2782,  2842,  2894,  2954,  2984,  3000,  3028,  3336,
+     3456,  3696,  3712,  3728,  3744,  3766,  3832,  3896,
+     3912,  3928,  3944,  3968,  4008,  4040,  4056,  4106,
+     4138,  4170,  4202,  4234,  4266,  4296,  4312,  4344,
+     4408,  4424,  4442,  4472,  4488,  4504,  6148,  6198,
+     6264,  6280,  6360,  6429,  6505,  6529, 61448, 61468,
+    61512, 61534, 61592, 61610, 61642, 61672, 61688, 61704,
+    61726, 61784, 61800, 61816, 61836, 61880, 61896, 61914,
+    61948, 61998, 62062, 62122, 62154, 62184, 62200, 62218,
+    62252, 62302, 62364, 62410, 62442, 62478, 62536, 62554,
+    62584, 62604, 62640, 62648, 62656, 62664, 62730, 62766,
+    62830, 62890, 62924, 62974, 63032, 63050, 63082, 63118,
+    63182, 63242, 63274, 63310, 63368, 63390,
+  };
+#define HIBIT ((unsigned char)0x80)
+  unsigned char aChar[] = {
+    '\0',      'a',       'c',       'e',       'i',       'n',
+    'o',       'u',       'y',       'y',       'a',       'c',
+    'd',       'e',       'e',       'g',       'h',       'i',
+    'j',       'k',       'l',       'n',       'o',       'r',
+    's',       't',       'u',       'u',       'w',       'y',
+    'z',       'o',       'u',       'a',       'i',       'o',
+    'u',       'u'|HIBIT, 'a'|HIBIT, 'g',       'k',       'o',
+    'o'|HIBIT, 'j',       'g',       'n',       'a'|HIBIT, 'a',
+    'e',       'i',       'o',       'r',       'u',       's',
+    't',       'h',       'a',       'e',       'o'|HIBIT, 'o',
+    'o'|HIBIT, 'y',       '\0',      '\0',      '\0',      '\0',
+    '\0',      '\0',      '\0',      '\0',      'a',       'b',
+    'c'|HIBIT, 'd',       'd',       'e'|HIBIT, 'e',       'e'|HIBIT,
+    'f',       'g',       'h',       'h',       'i',       'i'|HIBIT,
+    'k',       'l',       'l'|HIBIT, 'l',       'm',       'n',
+    'o'|HIBIT, 'p',       'r',       'r'|HIBIT, 'r',       's',
+    's'|HIBIT, 't',       'u',       'u'|HIBIT, 'v',       'w',
+    'w',       'x',       'y',       'z',       'h',       't',
+    'w',       'y',       'a',       'a'|HIBIT, 'a'|HIBIT, 'a'|HIBIT,
+    'e',       'e'|HIBIT, 'e'|HIBIT, 'i',       'o',       'o'|HIBIT,
+    'o'|HIBIT, 'o'|HIBIT, 'u',       'u'|HIBIT, 'u'|HIBIT, 'y',
+  };
+
+  unsigned int key = (((unsigned int)c)<<3) | 0x00000007;
+  int iRes = 0;
+  int iHi = sizeof(aDia)/sizeof(aDia[0]) - 1;
+  int iLo = 0;
+  while( iHi>=iLo ){
+    int iTest = (iHi + iLo) / 2;
+    if( key >= aDia[iTest] ){
+      iRes = iTest;
+      iLo = iTest+1;
+    }else{
+      iHi = iTest-1;
+    }
+  }
+  assert( key>=aDia[iRes] );
+  if( bComplex==0 && (aChar[iRes] & 0x80) ) return c;
+  return (c > (aDia[iRes]>>3) + (aDia[iRes]&0x07)) ? c : ((int)aChar[iRes] & 0x7F);
+}
+
+
+/*
+** Return true if the argument interpreted as a unicode codepoint
+** is a diacritical modifier character.
+*/
+SQLITE_PRIVATE int sqlite3FtsUnicodeIsdiacritic(int c){
+  unsigned int mask0 = 0x08029FDF;
+  unsigned int mask1 = 0x000361F8;
+  if( c<768 || c>817 ) return 0;
+  return (c < 768+32) ?
+      (mask0 & ((unsigned int)1 << (c-768))) :
+      (mask1 & ((unsigned int)1 << (c-768-32)));
+}
+
+
+/*
+** Interpret the argument as a unicode codepoint. If the codepoint
+** is an upper case character that has a lower case equivalent,
+** return the codepoint corresponding to the lower case version.
+** Otherwise, return a copy of the argument.
+**
+** The results are undefined if the value passed to this function
+** is less than zero.
+*/
+SQLITE_PRIVATE int sqlite3FtsUnicodeFold(int c, int eRemoveDiacritic){
+  /* Each entry in the following array defines a rule for folding a range
+  ** of codepoints to lower case. The rule applies to a range of nRange
+  ** codepoints starting at codepoint iCode.
+  **
+  ** If the least significant bit in flags is clear, then the rule applies
+  ** to all nRange codepoints (i.e. all nRange codepoints are upper case and
+  ** need to be folded). Or, if it is set, then the rule only applies to
+  ** every second codepoint in the range, starting with codepoint C.
+  **
+  ** The 7 most significant bits in flags are an index into the aiOff[]
+  ** array. If a specific codepoint C does require folding, then its lower
+  ** case equivalent is ((C + aiOff[flags>>1]) & 0xFFFF).
+  **
+  ** The contents of this array are generated by parsing the CaseFolding.txt
+  ** file distributed as part of the "Unicode Character Database". See
+  ** http://www.unicode.org for details.
+  */
+  static const struct TableEntry {
+    unsigned short iCode;
+    unsigned char flags;
+    unsigned char nRange;
+  } aEntry[] = {
+    {65, 14, 26},          {181, 64, 1},          {192, 14, 23},
+    {216, 14, 7},          {256, 1, 48},          {306, 1, 6},
+    {313, 1, 16},          {330, 1, 46},          {376, 116, 1},
+    {377, 1, 6},           {383, 104, 1},         {385, 50, 1},
+    {386, 1, 4},           {390, 44, 1},          {391, 0, 1},
+    {393, 42, 2},          {395, 0, 1},           {398, 32, 1},
+    {399, 38, 1},          {400, 40, 1},          {401, 0, 1},
+    {403, 42, 1},          {404, 46, 1},          {406, 52, 1},
+    {407, 48, 1},          {408, 0, 1},           {412, 52, 1},
+    {413, 54, 1},          {415, 56, 1},          {416, 1, 6},
+    {422, 60, 1},          {423, 0, 1},           {425, 60, 1},
+    {428, 0, 1},           {430, 60, 1},          {431, 0, 1},
+    {433, 58, 2},          {435, 1, 4},           {439, 62, 1},
+    {440, 0, 1},           {444, 0, 1},           {452, 2, 1},
+    {453, 0, 1},           {455, 2, 1},           {456, 0, 1},
+    {458, 2, 1},           {459, 1, 18},          {478, 1, 18},
+    {497, 2, 1},           {498, 1, 4},           {502, 122, 1},
+    {503, 134, 1},         {504, 1, 40},          {544, 110, 1},
+    {546, 1, 18},          {570, 70, 1},          {571, 0, 1},
+    {573, 108, 1},         {574, 68, 1},          {577, 0, 1},
+    {579, 106, 1},         {580, 28, 1},          {581, 30, 1},
+    {582, 1, 10},          {837, 36, 1},          {880, 1, 4},
+    {886, 0, 1},           {902, 18, 1},          {904, 16, 3},
+    {908, 26, 1},          {910, 24, 2},          {913, 14, 17},
+    {931, 14, 9},          {962, 0, 1},           {975, 4, 1},
+    {976, 140, 1},         {977, 142, 1},         {981, 146, 1},
+    {982, 144, 1},         {984, 1, 24},          {1008, 136, 1},
+    {1009, 138, 1},        {1012, 130, 1},        {1013, 128, 1},
+    {1015, 0, 1},          {1017, 152, 1},        {1018, 0, 1},
+    {1021, 110, 3},        {1024, 34, 16},        {1040, 14, 32},
+    {1120, 1, 34},         {1162, 1, 54},         {1216, 6, 1},
+    {1217, 1, 14},         {1232, 1, 88},         {1329, 22, 38},
+    {4256, 66, 38},        {4295, 66, 1},         {4301, 66, 1},
+    {7680, 1, 150},        {7835, 132, 1},        {7838, 96, 1},
+    {7840, 1, 96},         {7944, 150, 8},        {7960, 150, 6},
+    {7976, 150, 8},        {7992, 150, 8},        {8008, 150, 6},
+    {8025, 151, 8},        {8040, 150, 8},        {8072, 150, 8},
+    {8088, 150, 8},        {8104, 150, 8},        {8120, 150, 2},
+    {8122, 126, 2},        {8124, 148, 1},        {8126, 100, 1},
+    {8136, 124, 4},        {8140, 148, 1},        {8152, 150, 2},
+    {8154, 120, 2},        {8168, 150, 2},        {8170, 118, 2},
+    {8172, 152, 1},        {8184, 112, 2},        {8186, 114, 2},
+    {8188, 148, 1},        {8486, 98, 1},         {8490, 92, 1},
+    {8491, 94, 1},         {8498, 12, 1},         {8544, 8, 16},
+    {8579, 0, 1},          {9398, 10, 26},        {11264, 22, 47},
+    {11360, 0, 1},         {11362, 88, 1},        {11363, 102, 1},
+    {11364, 90, 1},        {11367, 1, 6},         {11373, 84, 1},
+    {11374, 86, 1},        {11375, 80, 1},        {11376, 82, 1},
+    {11378, 0, 1},         {11381, 0, 1},         {11390, 78, 2},
+    {11392, 1, 100},       {11499, 1, 4},         {11506, 0, 1},
+    {42560, 1, 46},        {42624, 1, 24},        {42786, 1, 14},
+    {42802, 1, 62},        {42873, 1, 4},         {42877, 76, 1},
+    {42878, 1, 10},        {42891, 0, 1},         {42893, 74, 1},
+    {42896, 1, 4},         {42912, 1, 10},        {42922, 72, 1},
+    {65313, 14, 26},
+  };
+  static const unsigned short aiOff[] = {
+   1,     2,     8,     15,    16,    26,    28,    32,
+   37,    38,    40,    48,    63,    64,    69,    71,
+   79,    80,    116,   202,   203,   205,   206,   207,
+   209,   210,   211,   213,   214,   217,   218,   219,
+   775,   7264,  10792, 10795, 23228, 23256, 30204, 54721,
+   54753, 54754, 54756, 54787, 54793, 54809, 57153, 57274,
+   57921, 58019, 58363, 61722, 65268, 65341, 65373, 65406,
+   65408, 65410, 65415, 65424, 65436, 65439, 65450, 65462,
+   65472, 65476, 65478, 65480, 65482, 65488, 65506, 65511,
+   65514, 65521, 65527, 65528, 65529,
+  };
+
+  int ret = c;
+
+  assert( sizeof(unsigned short)==2 && sizeof(unsigned char)==1 );
+
+  if( c<128 ){
+    if( c>='A' && c<='Z' ) ret = c + ('a' - 'A');
+  }else if( c<65536 ){
+    const struct TableEntry *p;
+    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
+    int iLo = 0;
+    int iRes = -1;
+
+    assert( c>aEntry[0].iCode );
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      int cmp = (c - aEntry[iTest].iCode);
+      if( cmp>=0 ){
+        iRes = iTest;
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+
+    assert( iRes>=0 && c>=aEntry[iRes].iCode );
+    p = &aEntry[iRes];
+    if( c<(p->iCode + p->nRange) && 0==(0x01 & p->flags & (p->iCode ^ c)) ){
+      ret = (c + (aiOff[p->flags>>1])) & 0x0000FFFF;
+      assert( ret>0 );
+    }
+
+    if( eRemoveDiacritic ){
+      ret = remove_diacritic(ret, eRemoveDiacritic==2);
+    }
+  }
+
+  else if( c>=66560 && c<66600 ){
+    ret = c + 40;
+  }
+
+  return ret;
+}
+#endif /* defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4) */
+#endif /* !defined(SQLITE_DISABLE_FTS3_UNICODE) */
+
+/************** End of fts3_unicode2.c ***************************************/
+/************** Begin file json.c ********************************************/
+/*
+** 2015-08-12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** SQLite JSON functions.
+**
+** This file began as an extension in ext/misc/json1.c in 2015.  That
+** extension proved so useful that it has now been moved into the core.
+**
+** The original design stored all JSON as pure text, canonical RFC-8259.
+** Support for JSON-5 extensions was added with version 3.42.0 (2023-05-16).
+** All generated JSON text still conforms strictly to RFC-8259, but text
+** with JSON-5 extensions is accepted as input.
+**
+** Beginning with version 3.45.0 (circa 2024-01-01), these routines also
+** accept BLOB values that have JSON encoded using a binary representation
+** called "JSONB".  The name JSONB comes from PostgreSQL, however the on-disk
+** format SQLite JSONB is completely different and incompatible with
+** PostgreSQL JSONB.
+**
+** Decoding and interpreting JSONB is still O(N) where N is the size of
+** the input, the same as text JSON.  However, the constant of proportionality
+** for JSONB is much smaller due to faster parsing.  The size of each
+** element in JSONB is encoded in its header, so there is no need to search
+** for delimiters using persnickety syntax rules.  JSONB seems to be about
+** 3x faster than text JSON as a result.  JSONB is also tends to be slightly
+** smaller than text JSON, by 5% or 10%, but there are corner cases where
+** JSONB can be slightly larger.  So you are not far mistaken to say that
+** a JSONB blob is the same size as the equivalent RFC-8259 text.
+**
+**
+** THE JSONB ENCODING:
+**
+** Every JSON element is encoded in JSONB as a header and a payload.
+** The header is between 1 and 9 bytes in size.  The payload is zero
+** or more bytes.
+**
+** The lower 4 bits of the first byte of the header determines the
+** element type:
+**
+**    0:   NULL
+**    1:   TRUE
+**    2:   FALSE
+**    3:   INT        -- RFC-8259 integer literal
+**    4:   INT5       -- JSON5 integer literal
+**    5:   FLOAT      -- RFC-8259 floating point literal
+**    6:   FLOAT5     -- JSON5 floating point literal
+**    7:   TEXT       -- Text literal acceptable to both SQL and JSON
+**    8:   TEXTJ      -- Text containing RFC-8259 escapes
+**    9:   TEXT5      -- Text containing JSON5 and/or RFC-8259 escapes
+**   10:   TEXTRAW    -- Text containing unescaped syntax characters
+**   11:   ARRAY
+**   12:   OBJECT
+**
+** The other three possible values (13-15) are reserved for future
+** enhancements.
+**
+** The upper 4 bits of the first byte determine the size of the header
+** and sometimes also the size of the payload.  If X is the first byte
+** of the element and if X>>4 is between 0 and 11, then the payload
+** will be that many bytes in size and the header is exactly one byte
+** in size.  Other four values for X>>4 (12-15) indicate that the header
+** is more than one byte in size and that the payload size is determined
+** by the remainder of the header, interpreted as a unsigned big-endian
+** integer.
+**
+**   Value of X>>4         Size integer        Total header size
+**   -------------     --------------------    -----------------
+**        12           1 byte (0-255)                2
+**        13           2 byte (0-65535)              3
+**        14           4 byte (0-4294967295)         5
+**        15           8 byte (0-1.8e19)             9
+**
+** The payload size need not be expressed in its minimal form.  For example,
+** if the payload size is 10, the size can be expressed in any of 5 different
+** ways: (1) (X>>4)==10, (2) (X>>4)==12 following by on 0x0a byte,
+** (3) (X>>4)==13 followed by 0x00 and 0x0a, (4) (X>>4)==14 followed by
+** 0x00 0x00 0x00 0x0a, or (5) (X>>4)==15 followed by 7 bytes of 0x00 and
+** a single byte of 0x0a.  The shorter forms are preferred, of course, but
+** sometimes when generating JSONB, the payload size is not known in advance
+** and it is convenient to reserve sufficient header space to cover the
+** largest possible payload size and then come back later and patch up
+** the size when it becomes known, resulting in a non-minimal encoding.
+**
+** The value (X>>4)==15 is not actually used in the current implementation
+** (as SQLite is currently unable handle BLOBs larger than about 2GB)
+** but is included in the design to allow for future enhancements.
+**
+** The payload follows the header.  NULL, TRUE, and FALSE have no payload and
+** their payload size must always be zero.  The payload for INT, INT5,
+** FLOAT, FLOAT5, TEXT, TEXTJ, TEXT5, and TEXTROW is text.  Note that the
+** "..." or '...' delimiters are omitted from the various text encodings.
+** The payload for ARRAY and OBJECT is a list of additional elements that
+** are the content for the array or object.  The payload for an OBJECT
+** must be an even number of elements.  The first element of each pair is
+** the label and must be of type TEXT, TEXTJ, TEXT5, or TEXTRAW.
+**
+** A valid JSONB blob consists of a single element, as described above.
+** Usually this will be an ARRAY or OBJECT element which has many more
+** elements as its content.  But the overall blob is just a single element.
+**
+** Input validation for JSONB blobs simply checks that the element type
+** code is between 0 and 12 and that the total size of the element
+** (header plus payload) is the same as the size of the BLOB.  If those
+** checks are true, the BLOB is assumed to be JSONB and processing continues.
+** Errors are only raised if some other miscoding is discovered during
+** processing.
+**
+** Additional information can be found in the doc/jsonb.md file of the
+** canonical SQLite source tree.
+*/
+#ifndef SQLITE_OMIT_JSON
+/* #include "sqliteInt.h" */
+
+/* JSONB element types
+*/
+#define JSONB_NULL     0   /* "null" */
+#define JSONB_TRUE     1   /* "true" */
+#define JSONB_FALSE    2   /* "false" */
+#define JSONB_INT      3   /* integer acceptable to JSON and SQL */
+#define JSONB_INT5     4   /* integer in 0x000 notation */
+#define JSONB_FLOAT    5   /* float acceptable to JSON and SQL */
+#define JSONB_FLOAT5   6   /* float with JSON5 extensions */
+#define JSONB_TEXT     7   /* Text compatible with both JSON and SQL */
+#define JSONB_TEXTJ    8   /* Text with JSON escapes */
+#define JSONB_TEXT5    9   /* Text with JSON-5 escape */
+#define JSONB_TEXTRAW 10   /* SQL text that needs escaping for JSON */
+#define JSONB_ARRAY   11   /* An array */
+#define JSONB_OBJECT  12   /* An object */
+
+/* Human-readable names for the JSONB values.  The index for each
+** string must correspond to the JSONB_* integer above.
+*/
+static const char * const jsonbType[] = {
+  "null", "true", "false", "integer", "integer",
+  "real", "real", "text",  "text",    "text",
+  "text", "array", "object", "", "", "", ""
+};
+
+/*
+** Growing our own isspace() routine this way is twice as fast as
+** the library isspace() function, resulting in a 7% overall performance
+** increase for the text-JSON parser.  (Ubuntu14.10 gcc 4.8.4 x64 with -Os).
+*/
+static const char jsonIsSpace[] = {
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 1, 1, 0, 0, 1, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  1, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+};
+#define jsonIsspace(x) (jsonIsSpace[(unsigned char)x])
+
+/*
+** The set of all space characters recognized by jsonIsspace().
+** Useful as the second argument to strspn().
+*/
+static const char jsonSpaces[] = "\011\012\015\040";
+
+/*
+** Characters that are special to JSON.  Control characters,
+** '"' and '\\' and '\''.  Actually, '\'' is not special to
+** canonical JSON, but it is special in JSON-5, so we include
+** it in the set of special characters.
+*/
+static const char jsonIsOk[256] = {
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
+  1, 1, 0, 1, 1, 1, 1, 0,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 0, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1,  1, 1, 1, 1, 1, 1, 1, 1
+};
+
+/* Objects */
+typedef struct JsonCache JsonCache;
+typedef struct JsonString JsonString;
+typedef struct JsonParse JsonParse;
+
+/*
+** Magic number used for the JSON parse cache in sqlite3_get_auxdata()
+*/
+#define JSON_CACHE_ID    (-429938)  /* Cache entry */
+#define JSON_CACHE_SIZE  4          /* Max number of cache entries */
+
+/*
+** jsonUnescapeOneChar() returns this invalid code point if it encounters
+** a syntax error.
+*/
+#define JSON_INVALID_CHAR 0x99999
+
+/* A cache mapping JSON text into JSONB blobs.
+**
+** Each cache entry is a JsonParse object with the following restrictions:
+**
+**    *   The bReadOnly flag must be set
+**
+**    *   The aBlob[] array must be owned by the JsonParse object.  In other
+**        words, nBlobAlloc must be non-zero.
+**
+**    *   eEdit and delta must be zero.
+**
+**    *   zJson must be an RCStr.  In other words bJsonIsRCStr must be true.
+*/
+struct JsonCache {
+  sqlite3 *db;                    /* Database connection */
+  int nUsed;                      /* Number of active entries in the cache */
+  JsonParse *a[JSON_CACHE_SIZE];  /* One line for each cache entry */
+};
+
+/* An instance of this object represents a JSON string
+** under construction.  Really, this is a generic string accumulator
+** that can be and is used to create strings other than JSON.
+**
+** If the generated string is longer than will fit into the zSpace[] buffer,
+** then it will be an RCStr string.  This aids with caching of large
+** JSON strings.
+*/
+struct JsonString {
+  sqlite3_context *pCtx;   /* Function context - put error messages here */
+  char *zBuf;              /* Append JSON content here */
+  u64 nAlloc;              /* Bytes of storage available in zBuf[] */
+  u64 nUsed;               /* Bytes of zBuf[] currently used */
+  u8 bStatic;              /* True if zBuf is static space */
+  u8 eErr;                 /* True if an error has been encountered */
+  char zSpace[100];        /* Initial static space */
+};
+
+/* Allowed values for JsonString.eErr */
+#define JSTRING_OOM         0x01   /* Out of memory */
+#define JSTRING_MALFORMED   0x02   /* Malformed JSONB */
+#define JSTRING_ERR         0x04   /* Error already sent to sqlite3_result */
+
+/* The "subtype" set for text JSON values passed through using
+** sqlite3_result_subtype() and sqlite3_value_subtype().
+*/
+#define JSON_SUBTYPE  74    /* Ascii for "J" */
+
+/*
+** Bit values for the flags passed into various SQL function implementations
+** via the sqlite3_user_data() value.
+*/
+#define JSON_JSON      0x01        /* Result is always JSON */
+#define JSON_SQL       0x02        /* Result is always SQL */
+#define JSON_ABPATH    0x03        /* Allow abbreviated JSON path specs */
+#define JSON_ISSET     0x04        /* json_set(), not json_insert() */
+#define JSON_BLOB      0x08        /* Use the BLOB output format */
+
+
+/* A parsed JSON value.  Lifecycle:
+**
+**   1.  JSON comes in and is parsed into a JSONB value in aBlob.  The
+**       original text is stored in zJson.  This step is skipped if the
+**       input is JSONB instead of text JSON.
+**
+**   2.  The aBlob[] array is searched using the JSON path notation, if needed.
+**
+**   3.  Zero or more changes are made to aBlob[] (via json_remove() or
+**       json_replace() or json_patch() or similar).
+**
+**   4.  New JSON text is generated from the aBlob[] for output.  This step
+**       is skipped if the function is one of the jsonb_* functions that
+**       returns JSONB instead of text JSON.
+*/
+struct JsonParse {
+  u8 *aBlob;         /* JSONB representation of JSON value */
+  u32 nBlob;         /* Bytes of aBlob[] actually used */
+  u32 nBlobAlloc;    /* Bytes allocated to aBlob[].  0 if aBlob is external */
+  char *zJson;       /* Json text used for parsing */
+  sqlite3 *db;       /* The database connection to which this object belongs */
+  int nJson;         /* Length of the zJson string in bytes */
+  u32 nJPRef;        /* Number of references to this object */
+  u32 iErr;          /* Error location in zJson[] */
+  u16 iDepth;        /* Nesting depth */
+  u8 nErr;           /* Number of errors seen */
+  u8 oom;            /* Set to true if out of memory */
+  u8 bJsonIsRCStr;   /* True if zJson is an RCStr */
+  u8 hasNonstd;      /* True if input uses non-standard features like JSON5 */
+  u8 bReadOnly;      /* Do not modify. */
+  /* Search and edit information.  See jsonLookupStep() */
+  u8 eEdit;          /* Edit operation to apply */
+  int delta;         /* Size change due to the edit */
+  u32 nIns;          /* Number of bytes to insert */
+  u32 iLabel;        /* Location of label if search landed on an object value */
+  u8 *aIns;          /* Content to be inserted */
+};
+
+/* Allowed values for JsonParse.eEdit */
+#define JEDIT_DEL   1   /* Delete if exists */
+#define JEDIT_REPL  2   /* Overwrite if exists */
+#define JEDIT_INS   3   /* Insert if not exists */
+#define JEDIT_SET   4   /* Insert or overwrite */
+
+/*
+** Maximum nesting depth of JSON for this implementation.
+**
+** This limit is needed to avoid a stack overflow in the recursive
+** descent parser.  A depth of 1000 is far deeper than any sane JSON
+** should go.  Historical note: This limit was 2000 prior to version 3.42.0
+*/
+#ifndef SQLITE_JSON_MAX_DEPTH
+# define JSON_MAX_DEPTH  1000
+#else
+# define JSON_MAX_DEPTH SQLITE_JSON_MAX_DEPTH
+#endif
+
+/*
+** Allowed values for the flgs argument to jsonParseFuncArg();
+*/
+#define JSON_EDITABLE  0x01   /* Generate a writable JsonParse object */
+#define JSON_KEEPERROR 0x02   /* Return non-NULL even if there is an error */
+
+/**************************************************************************
+** Forward references
+**************************************************************************/
+static void jsonReturnStringAsBlob(JsonString*);
+static int jsonFuncArgMightBeBinary(sqlite3_value *pJson);
+static u32 jsonTranslateBlobToText(const JsonParse*,u32,JsonString*);
+static void jsonReturnParse(sqlite3_context*,JsonParse*);
+static JsonParse *jsonParseFuncArg(sqlite3_context*,sqlite3_value*,u32);
+static void jsonParseFree(JsonParse*);
+static u32 jsonbPayloadSize(const JsonParse*, u32, u32*);
+static u32 jsonUnescapeOneChar(const char*, u32, u32*);
+
+/**************************************************************************
+** Utility routines for dealing with JsonCache objects
+**************************************************************************/
+
+/*
+** Free a JsonCache object.
+*/
+static void jsonCacheDelete(JsonCache *p){
+  int i;
+  for(i=0; i<p->nUsed; i++){
+    jsonParseFree(p->a[i]);
+  }
+  sqlite3DbFree(p->db, p);
+}
+static void jsonCacheDeleteGeneric(void *p){
+  jsonCacheDelete((JsonCache*)p);
+}
+
+/*
+** Insert a new entry into the cache.  If the cache is full, expel
+** the least recently used entry.  Return SQLITE_OK on success or a
+** result code otherwise.
+**
+** Cache entries are stored in age order, oldest first.
+*/
+static int jsonCacheInsert(
+  sqlite3_context *ctx,   /* The SQL statement context holding the cache */
+  JsonParse *pParse       /* The parse object to be added to the cache */
+){
+  JsonCache *p;
+
+  assert( pParse->zJson!=0 );
+  assert( pParse->bJsonIsRCStr );
+  assert( pParse->delta==0 );
+  p = sqlite3_get_auxdata(ctx, JSON_CACHE_ID);
+  if( p==0 ){
+    sqlite3 *db = sqlite3_context_db_handle(ctx);
+    p = sqlite3DbMallocZero(db, sizeof(*p));
+    if( p==0 ) return SQLITE_NOMEM;
+    p->db = db;
+    sqlite3_set_auxdata(ctx, JSON_CACHE_ID, p, jsonCacheDeleteGeneric);
+    p = sqlite3_get_auxdata(ctx, JSON_CACHE_ID);
+    if( p==0 ) return SQLITE_NOMEM;
+  }
+  if( p->nUsed >= JSON_CACHE_SIZE ){
+    jsonParseFree(p->a[0]);
+    memmove(p->a, &p->a[1], (JSON_CACHE_SIZE-1)*sizeof(p->a[0]));
+    p->nUsed = JSON_CACHE_SIZE-1;
+  }
+  assert( pParse->nBlobAlloc>0 );
+  pParse->eEdit = 0;
+  pParse->nJPRef++;
+  pParse->bReadOnly = 1;
+  p->a[p->nUsed] = pParse;
+  p->nUsed++;
+  return SQLITE_OK;
+}
+
+/*
+** Search for a cached translation the json text supplied by pArg.  Return
+** the JsonParse object if found.  Return NULL if not found.
+**
+** When a match if found, the matching entry is moved to become the
+** most-recently used entry if it isn't so already.
+**
+** The JsonParse object returned still belongs to the Cache and might
+** be deleted at any moment.  If the caller whants the JsonParse to
+** linger, it needs to increment the nPJRef reference counter.
+*/
+static JsonParse *jsonCacheSearch(
+  sqlite3_context *ctx,    /* The SQL statement context holding the cache */
+  sqlite3_value *pArg      /* Function argument containing SQL text */
+){
+  JsonCache *p;
+  int i;
+  const char *zJson;
+  int nJson;
+
+  if( sqlite3_value_type(pArg)!=SQLITE_TEXT ){
+    return 0;
+  }
+  zJson = (const char*)sqlite3_value_text(pArg);
+  if( zJson==0 ) return 0;
+  nJson = sqlite3_value_bytes(pArg);
+
+  p = sqlite3_get_auxdata(ctx, JSON_CACHE_ID);
+  if( p==0 ){
+    return 0;
+  }
+  for(i=0; i<p->nUsed; i++){
+    if( p->a[i]->zJson==zJson ) break;
+  }
+  if( i>=p->nUsed ){
+    for(i=0; i<p->nUsed; i++){
+      if( p->a[i]->nJson!=nJson ) continue;
+      if( memcmp(p->a[i]->zJson, zJson, nJson)==0 ) break;
+    }
+  }
+  if( i<p->nUsed ){
+    if( i<p->nUsed-1 ){
+      /* Make the matching entry the most recently used entry */
+      JsonParse *tmp = p->a[i];
+      memmove(&p->a[i], &p->a[i+1], (p->nUsed-i-1)*sizeof(tmp));
+      p->a[p->nUsed-1] = tmp;
+      i = p->nUsed - 1;
+    }
+    assert( p->a[i]->delta==0 );
+    return p->a[i];
+  }else{
+    return 0;
+  }
+}
+
+/**************************************************************************
+** Utility routines for dealing with JsonString objects
+**************************************************************************/
+
+/* Turn uninitialized bulk memory into a valid JsonString object
+** holding a zero-length string.
+*/
+static void jsonStringZero(JsonString *p){
+  p->zBuf = p->zSpace;
+  p->nAlloc = sizeof(p->zSpace);
+  p->nUsed = 0;
+  p->bStatic = 1;
+}
+
+/* Initialize the JsonString object
+*/
+static void jsonStringInit(JsonString *p, sqlite3_context *pCtx){
+  p->pCtx = pCtx;
+  p->eErr = 0;
+  jsonStringZero(p);
+}
+
+/* Free all allocated memory and reset the JsonString object back to its
+** initial state.
+*/
+static void jsonStringReset(JsonString *p){
+  if( !p->bStatic ) sqlite3RCStrUnref(p->zBuf);
+  jsonStringZero(p);
+}
+
+/* Report an out-of-memory (OOM) condition
+*/
+static void jsonStringOom(JsonString *p){
+  p->eErr |= JSTRING_OOM;
+  if( p->pCtx ) sqlite3_result_error_nomem(p->pCtx);
+  jsonStringReset(p);
+}
+
+/* Enlarge pJson->zBuf so that it can hold at least N more bytes.
+** Return zero on success.  Return non-zero on an OOM error
+*/
+static int jsonStringGrow(JsonString *p, u32 N){
+  u64 nTotal = N<p->nAlloc ? p->nAlloc*2 : p->nAlloc+N+10;
+  char *zNew;
+  if( p->bStatic ){
+    if( p->eErr ) return 1;
+    zNew = sqlite3RCStrNew(nTotal);
+    if( zNew==0 ){
+      jsonStringOom(p);
+      return SQLITE_NOMEM;
+    }
+    memcpy(zNew, p->zBuf, (size_t)p->nUsed);
+    p->zBuf = zNew;
+    p->bStatic = 0;
+  }else{
+    p->zBuf = sqlite3RCStrResize(p->zBuf, nTotal);
+    if( p->zBuf==0 ){
+      p->eErr |= JSTRING_OOM;
+      jsonStringZero(p);
+      return SQLITE_NOMEM;
+    }
+  }
+  p->nAlloc = nTotal;
+  return SQLITE_OK;
+}
+
+/* Append N bytes from zIn onto the end of the JsonString string.
+*/
+static SQLITE_NOINLINE void jsonStringExpandAndAppend(
+  JsonString *p,
+  const char *zIn,
+  u32 N
+){
+  assert( N>0 );
+  if( jsonStringGrow(p,N) ) return;
+  memcpy(p->zBuf+p->nUsed, zIn, N);
+  p->nUsed += N;
+}
+static void jsonAppendRaw(JsonString *p, const char *zIn, u32 N){
+  if( N==0 ) return;
+  if( N+p->nUsed >= p->nAlloc ){
+    jsonStringExpandAndAppend(p,zIn,N);
+  }else{
+    memcpy(p->zBuf+p->nUsed, zIn, N);
+    p->nUsed += N;
+  }
+}
+static void jsonAppendRawNZ(JsonString *p, const char *zIn, u32 N){
+  assert( N>0 );
+  if( N+p->nUsed >= p->nAlloc ){
+    jsonStringExpandAndAppend(p,zIn,N);
+  }else{
+    memcpy(p->zBuf+p->nUsed, zIn, N);
+    p->nUsed += N;
+  }
+}
+
+/* Append formatted text (not to exceed N bytes) to the JsonString.
+*/
+static void jsonPrintf(int N, JsonString *p, const char *zFormat, ...){
+  va_list ap;
+  if( (p->nUsed + N >= p->nAlloc) && jsonStringGrow(p, N) ) return;
+  va_start(ap, zFormat);
+  sqlite3_vsnprintf(N, p->zBuf+p->nUsed, zFormat, ap);
+  va_end(ap);
+  p->nUsed += (int)strlen(p->zBuf+p->nUsed);
+}
+
+/* Append a single character
+*/
+static SQLITE_NOINLINE void jsonAppendCharExpand(JsonString *p, char c){
+  if( jsonStringGrow(p,1) ) return;
+  p->zBuf[p->nUsed++] = c;
+}
+static void jsonAppendChar(JsonString *p, char c){
+  if( p->nUsed>=p->nAlloc ){
+    jsonAppendCharExpand(p,c);
+  }else{
+    p->zBuf[p->nUsed++] = c;
+  }
+}
+
+/* Remove a single character from the end of the string
+*/
+static void jsonStringTrimOneChar(JsonString *p){
+  if( p->eErr==0 ){
+    assert( p->nUsed>0 );
+    p->nUsed--;
+  }
+}
+
+
+/* Make sure there is a zero terminator on p->zBuf[]
+**
+** Return true on success.  Return false if an OOM prevents this
+** from happening.
+*/
+static int jsonStringTerminate(JsonString *p){
+  jsonAppendChar(p, 0);
+  jsonStringTrimOneChar(p);
+  return p->eErr==0;
+}
+
+/* Append a comma separator to the output buffer, if the previous
+** character is not '[' or '{'.
+*/
+static void jsonAppendSeparator(JsonString *p){
+  char c;
+  if( p->nUsed==0 ) return;
+  c = p->zBuf[p->nUsed-1];
+  if( c=='[' || c=='{' ) return;
+  jsonAppendChar(p, ',');
+}
+
+/* c is a control character.  Append the canonical JSON representation
+** of that control character to p.
+**
+** This routine assumes that the output buffer has already been enlarged
+** sufficiently to hold the worst-case encoding plus a nul terminator.
+*/
+static void jsonAppendControlChar(JsonString *p, u8 c){
+  static const char aSpecial[] = {
+     0, 0, 0, 0, 0, 0, 0, 0, 'b', 't', 'n', 0, 'f', 'r', 0, 0,
+     0, 0, 0, 0, 0, 0, 0, 0,   0,   0,   0, 0,   0,   0, 0, 0
+  };
+  assert( sizeof(aSpecial)==32 );
+  assert( aSpecial['\b']=='b' );
+  assert( aSpecial['\f']=='f' );
+  assert( aSpecial['\n']=='n' );
+  assert( aSpecial['\r']=='r' );
+  assert( aSpecial['\t']=='t' );
+  assert( c>=0 && c<sizeof(aSpecial) );
+  assert( p->nUsed+7 <= p->nAlloc );
+  if( aSpecial[c] ){
+    p->zBuf[p->nUsed] = '\\';
+    p->zBuf[p->nUsed+1] = aSpecial[c];
+    p->nUsed += 2;
+  }else{
+    p->zBuf[p->nUsed] = '\\';
+    p->zBuf[p->nUsed+1] = 'u';
+    p->zBuf[p->nUsed+2] = '0';
+    p->zBuf[p->nUsed+3] = '0';
+    p->zBuf[p->nUsed+4] = "0123456789abcdef"[c>>4];
+    p->zBuf[p->nUsed+5] = "0123456789abcdef"[c&0xf];
+    p->nUsed += 6;
+  }
+}
+
+/* Append the N-byte string in zIn to the end of the JsonString string
+** under construction.  Enclose the string in double-quotes ("...") and
+** escape any double-quotes or backslash characters contained within the
+** string.
+**
+** This routine is a high-runner.  There is a measurable performance
+** increase associated with unwinding the jsonIsOk[] loop.
+*/
+static void jsonAppendString(JsonString *p, const char *zIn, u32 N){
+  u32 k;
+  u8 c;
+  const u8 *z = (const u8*)zIn;
+  if( z==0 ) return;
+  if( (N+p->nUsed+2 >= p->nAlloc) && jsonStringGrow(p,N+2)!=0 ) return;
+  p->zBuf[p->nUsed++] = '"';
+  while( 1 /*exit-by-break*/ ){
+    k = 0;
+    /* The following while() is the 4-way unwound equivalent of
+    **
+    **     while( k<N && jsonIsOk[z[k]] ){ k++; }
+    */
+    while( 1 /* Exit by break */ ){
+      if( k+3>=N ){
+        while( k<N && jsonIsOk[z[k]] ){ k++; }
+        break;
+      }
+      if( !jsonIsOk[z[k]] ){
+        break;
+      }
+      if( !jsonIsOk[z[k+1]] ){
+        k += 1;
+        break;
+      }
+      if( !jsonIsOk[z[k+2]] ){
+        k += 2;
+        break;
+      }
+      if( !jsonIsOk[z[k+3]] ){
+        k += 3;
+        break;
+      }else{
+        k += 4;
+      }
+    }
+    if( k>=N ){
+      if( k>0 ){
+        memcpy(&p->zBuf[p->nUsed], z, k);
+        p->nUsed += k;
+      }
+      break;
+    }
+    if( k>0 ){
+      memcpy(&p->zBuf[p->nUsed], z, k);
+      p->nUsed += k;
+      z += k;
+      N -= k;
+    }
+    c = z[0];
+    if( c=='"' || c=='\\' ){
+      if( (p->nUsed+N+3 > p->nAlloc) && jsonStringGrow(p,N+3)!=0 ) return;
+      p->zBuf[p->nUsed++] = '\\';
+      p->zBuf[p->nUsed++] = c;
+    }else if( c=='\'' ){
+      p->zBuf[p->nUsed++] = c;
+    }else{
+      if( (p->nUsed+N+7 > p->nAlloc) && jsonStringGrow(p,N+7)!=0 ) return;
+      jsonAppendControlChar(p, c);
+    }
+    z++;
+    N--;
+  }
+  p->zBuf[p->nUsed++] = '"';
+  assert( p->nUsed<p->nAlloc );
+}
+
+/*
+** Append an sqlite3_value (such as a function parameter) to the JSON
+** string under construction in p.
+*/
+static void jsonAppendSqlValue(
+  JsonString *p,                 /* Append to this JSON string */
+  sqlite3_value *pValue          /* Value to append */
+){
+  switch( sqlite3_value_type(pValue) ){
+    case SQLITE_NULL: {
+      jsonAppendRawNZ(p, "null", 4);
+      break;
+    }
+    case SQLITE_FLOAT: {
+      jsonPrintf(100, p, "%!0.15g", sqlite3_value_double(pValue));
+      break;
+    }
+    case SQLITE_INTEGER: {
+      const char *z = (const char*)sqlite3_value_text(pValue);
+      u32 n = (u32)sqlite3_value_bytes(pValue);
+      jsonAppendRaw(p, z, n);
+      break;
+    }
+    case SQLITE_TEXT: {
+      const char *z = (const char*)sqlite3_value_text(pValue);
+      u32 n = (u32)sqlite3_value_bytes(pValue);
+      if( sqlite3_value_subtype(pValue)==JSON_SUBTYPE ){
+        jsonAppendRaw(p, z, n);
+      }else{
+        jsonAppendString(p, z, n);
+      }
+      break;
+    }
+    default: {
+      if( jsonFuncArgMightBeBinary(pValue) ){
+        JsonParse px;
+        memset(&px, 0, sizeof(px));
+        px.aBlob = (u8*)sqlite3_value_blob(pValue);
+        px.nBlob = sqlite3_value_bytes(pValue);
+        jsonTranslateBlobToText(&px, 0, p);
+      }else if( p->eErr==0 ){
+        sqlite3_result_error(p->pCtx, "JSON cannot hold BLOB values", -1);
+        p->eErr = JSTRING_ERR;
+        jsonStringReset(p);
+      }
+      break;
+    }
+  }
+}
+
+/* Make the text in p (which is probably a generated JSON text string)
+** the result of the SQL function.
+**
+** The JsonString is reset.
+**
+** If pParse and ctx are both non-NULL, then the SQL string in p is
+** loaded into the zJson field of the pParse object as a RCStr and the
+** pParse is added to the cache.
+*/
+static void jsonReturnString(
+  JsonString *p,            /* String to return */
+  JsonParse *pParse,        /* JSONB source or NULL */
+  sqlite3_context *ctx      /* Where to cache */
+){
+  assert( (pParse!=0)==(ctx!=0) );
+  assert( ctx==0 || ctx==p->pCtx );
+  if( p->eErr==0 ){
+    int flags = SQLITE_PTR_TO_INT(sqlite3_user_data(p->pCtx));
+    if( flags & JSON_BLOB ){
+      jsonReturnStringAsBlob(p);
+    }else if( p->bStatic ){
+      sqlite3_result_text64(p->pCtx, p->zBuf, p->nUsed,
+                            SQLITE_TRANSIENT, SQLITE_UTF8);
+    }else if( jsonStringTerminate(p) ){
+      if( pParse && pParse->bJsonIsRCStr==0 && pParse->nBlobAlloc>0 ){
+        int rc;
+        pParse->zJson = sqlite3RCStrRef(p->zBuf);
+        pParse->nJson = p->nUsed;
+        pParse->bJsonIsRCStr = 1;
+        rc = jsonCacheInsert(ctx, pParse);
+        if( rc==SQLITE_NOMEM ){
+          sqlite3_result_error_nomem(ctx);
+          jsonStringReset(p);
+          return;
+        }
+      }
+      sqlite3_result_text64(p->pCtx, sqlite3RCStrRef(p->zBuf), p->nUsed,
+                            sqlite3RCStrUnref,
+                            SQLITE_UTF8);
+    }else{
+      sqlite3_result_error_nomem(p->pCtx);
+    }
+  }else if( p->eErr & JSTRING_OOM ){
+    sqlite3_result_error_nomem(p->pCtx);
+  }else if( p->eErr & JSTRING_MALFORMED ){
+    sqlite3_result_error(p->pCtx, "malformed JSON", -1);
+  }
+  jsonStringReset(p);
+}
+
+/**************************************************************************
+** Utility routines for dealing with JsonParse objects
+**************************************************************************/
+
+/*
+** Reclaim all memory allocated by a JsonParse object.  But do not
+** delete the JsonParse object itself.
+*/
+static void jsonParseReset(JsonParse *pParse){
+  assert( pParse->nJPRef<=1 );
+  if( pParse->bJsonIsRCStr ){
+    sqlite3RCStrUnref(pParse->zJson);
+    pParse->zJson = 0;
+    pParse->nJson = 0;
+    pParse->bJsonIsRCStr = 0;
+  }
+  if( pParse->nBlobAlloc ){
+    sqlite3DbFree(pParse->db, pParse->aBlob);
+    pParse->aBlob = 0;
+    pParse->nBlob = 0;
+    pParse->nBlobAlloc = 0;
+  }
+}
+
+/*
+** Decrement the reference count on the JsonParse object.  When the
+** count reaches zero, free the object.
+*/
+static void jsonParseFree(JsonParse *pParse){
+  if( pParse ){
+    if( pParse->nJPRef>1 ){
+      pParse->nJPRef--;
+    }else{
+      jsonParseReset(pParse);
+      sqlite3DbFree(pParse->db, pParse);
+    }
+  }
+}
+
+/**************************************************************************
+** Utility routines for the JSON text parser
+**************************************************************************/
+
+/*
+** Translate a single byte of Hex into an integer.
+** This routine only gives a correct answer if h really is a valid hexadecimal
+** character:  0..9a..fA..F.  But unlike sqlite3HexToInt(), it does not
+** assert() if the digit is not hex.
+*/
+static u8 jsonHexToInt(int h){
+#ifdef SQLITE_ASCII
+  h += 9*(1&(h>>6));
+#endif
+#ifdef SQLITE_EBCDIC
+  h += 9*(1&~(h>>4));
+#endif
+  return (u8)(h & 0xf);
+}
+
+/*
+** Convert a 4-byte hex string into an integer
+*/
+static u32 jsonHexToInt4(const char *z){
+  u32 v;
+  v = (jsonHexToInt(z[0])<<12)
+    + (jsonHexToInt(z[1])<<8)
+    + (jsonHexToInt(z[2])<<4)
+    + jsonHexToInt(z[3]);
+  return v;
+}
+
+/*
+** Return true if z[] begins with 2 (or more) hexadecimal digits
+*/
+static int jsonIs2Hex(const char *z){
+  return sqlite3Isxdigit(z[0]) && sqlite3Isxdigit(z[1]);
+}
+
+/*
+** Return true if z[] begins with 4 (or more) hexadecimal digits
+*/
+static int jsonIs4Hex(const char *z){
+  return jsonIs2Hex(z) && jsonIs2Hex(&z[2]);
+}
+
+/*
+** Return the number of bytes of JSON5 whitespace at the beginning of
+** the input string z[].
+**
+** JSON5 whitespace consists of any of the following characters:
+**
+**    Unicode  UTF-8         Name
+**    U+0009   09            horizontal tab
+**    U+000a   0a            line feed
+**    U+000b   0b            vertical tab
+**    U+000c   0c            form feed
+**    U+000d   0d            carriage return
+**    U+0020   20            space
+**    U+00a0   c2 a0         non-breaking space
+**    U+1680   e1 9a 80      ogham space mark
+**    U+2000   e2 80 80      en quad
+**    U+2001   e2 80 81      em quad
+**    U+2002   e2 80 82      en space
+**    U+2003   e2 80 83      em space
+**    U+2004   e2 80 84      three-per-em space
+**    U+2005   e2 80 85      four-per-em space
+**    U+2006   e2 80 86      six-per-em space
+**    U+2007   e2 80 87      figure space
+**    U+2008   e2 80 88      punctuation space
+**    U+2009   e2 80 89      thin space
+**    U+200a   e2 80 8a      hair space
+**    U+2028   e2 80 a8      line separator
+**    U+2029   e2 80 a9      paragraph separator
+**    U+202f   e2 80 af      narrow no-break space (NNBSP)
+**    U+205f   e2 81 9f      medium mathematical space (MMSP)
+**    U+3000   e3 80 80      ideographical space
+**    U+FEFF   ef bb bf      byte order mark
+**
+** In addition, comments between '/', '*' and '*', '/' and
+** from '/', '/' to end-of-line are also considered to be whitespace.
+*/
+static int json5Whitespace(const char *zIn){
+  int n = 0;
+  const u8 *z = (u8*)zIn;
+  while( 1 /*exit by "goto whitespace_done"*/ ){
+    switch( z[n] ){
+      case 0x09:
+      case 0x0a:
+      case 0x0b:
+      case 0x0c:
+      case 0x0d:
+      case 0x20: {
+        n++;
+        break;
+      }
+      case '/': {
+        if( z[n+1]=='*' && z[n+2]!=0 ){
+          int j;
+          for(j=n+3; z[j]!='/' || z[j-1]!='*'; j++){
+            if( z[j]==0 ) goto whitespace_done;
+          }
+          n = j+1;
+          break;
+        }else if( z[n+1]=='/' ){
+          int j;
+          char c;
+          for(j=n+2; (c = z[j])!=0; j++){
+            if( c=='\n' || c=='\r' ) break;
+            if( 0xe2==(u8)c && 0x80==(u8)z[j+1]
+             && (0xa8==(u8)z[j+2] || 0xa9==(u8)z[j+2])
+            ){
+              j += 2;
+              break;
+            }
+          }
+          n = j;
+          if( z[n] ) n++;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xc2: {
+        if( z[n+1]==0xa0 ){
+          n += 2;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xe1: {
+        if( z[n+1]==0x9a && z[n+2]==0x80 ){
+          n += 3;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xe2: {
+        if( z[n+1]==0x80 ){
+          u8 c = z[n+2];
+          if( c<0x80 ) goto whitespace_done;
+          if( c<=0x8a || c==0xa8 || c==0xa9 || c==0xaf ){
+            n += 3;
+            break;
+          }
+        }else if( z[n+1]==0x81 && z[n+2]==0x9f ){
+          n += 3;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xe3: {
+        if( z[n+1]==0x80 && z[n+2]==0x80 ){
+          n += 3;
+          break;
+        }
+        goto whitespace_done;
+      }
+      case 0xef: {
+        if( z[n+1]==0xbb && z[n+2]==0xbf ){
+          n += 3;
+          break;
+        }
+        goto whitespace_done;
+      }
+      default: {
+        goto whitespace_done;
+      }
+    }
+  }
+  whitespace_done:
+  return n;
+}
+
+/*
+** Extra floating-point literals to allow in JSON.
+*/
+static const struct NanInfName {
+  char c1;
+  char c2;
+  char n;
+  char eType;
+  char nRepl;
+  char *zMatch;
+  char *zRepl;
+} aNanInfName[] = {
+  { 'i', 'I', 3, JSONB_FLOAT, 7, "inf", "9.0e999" },
+  { 'i', 'I', 8, JSONB_FLOAT, 7, "infinity", "9.0e999" },
+  { 'n', 'N', 3, JSONB_NULL, 4, "NaN", "null" },
+  { 'q', 'Q', 4, JSONB_NULL, 4, "QNaN", "null" },
+  { 's', 'S', 4, JSONB_NULL, 4, "SNaN", "null" },
+};
+
+
+/*
+** Report the wrong number of arguments for json_insert(), json_replace()
+** or json_set().
+*/
+static void jsonWrongNumArgs(
+  sqlite3_context *pCtx,
+  const char *zFuncName
+){
+  char *zMsg = sqlite3_mprintf("json_%s() needs an odd number of arguments",
+                               zFuncName);
+  sqlite3_result_error(pCtx, zMsg, -1);
+  sqlite3_free(zMsg);
+}
+
+/****************************************************************************
+** Utility routines for dealing with the binary BLOB representation of JSON
+****************************************************************************/
+
+/*
+** Expand pParse->aBlob so that it holds at least N bytes.
+**
+** Return the number of errors.
+*/
+static int jsonBlobExpand(JsonParse *pParse, u32 N){
+  u8 *aNew;
+  u32 t;
+  assert( N>pParse->nBlobAlloc );
+  if( pParse->nBlobAlloc==0 ){
+    t = 100;
+  }else{
+    t = pParse->nBlobAlloc*2;
+  }
+  if( t<N ) t = N+100;
+  aNew = sqlite3DbRealloc(pParse->db, pParse->aBlob, t);
+  if( aNew==0 ){ pParse->oom = 1; return 1; }
+  pParse->aBlob = aNew;
+  pParse->nBlobAlloc = t;
+  return 0;
+}
+
+/*
+** If pParse->aBlob is not previously editable (because it is taken
+** from sqlite3_value_blob(), as indicated by the fact that
+** pParse->nBlobAlloc==0 and pParse->nBlob>0) then make it editable
+** by making a copy into space obtained from malloc.
+**
+** Return true on success.  Return false on OOM.
+*/
+static int jsonBlobMakeEditable(JsonParse *pParse, u32 nExtra){
+  u8 *aOld;
+  u32 nSize;
+  assert( !pParse->bReadOnly );
+  if( pParse->oom ) return 0;
+  if( pParse->nBlobAlloc>0 ) return 1;
+  aOld = pParse->aBlob;
+  nSize = pParse->nBlob + nExtra;
+  pParse->aBlob = 0;
+  if( jsonBlobExpand(pParse, nSize) ){
+    return 0;
+  }
+  assert( pParse->nBlobAlloc >= pParse->nBlob + nExtra );
+  memcpy(pParse->aBlob, aOld, pParse->nBlob);
+  return 1;
+}
+
+/* Expand pParse->aBlob and append one bytes.
+*/
+static SQLITE_NOINLINE void jsonBlobExpandAndAppendOneByte(
+  JsonParse *pParse,
+  u8 c
+){
+  jsonBlobExpand(pParse, pParse->nBlob+1);
+  if( pParse->oom==0 ){
+    assert( pParse->nBlob+1<=pParse->nBlobAlloc );
+    pParse->aBlob[pParse->nBlob++] = c;
+  }
+}
+
+/* Append a single character.
+*/
+static void jsonBlobAppendOneByte(JsonParse *pParse, u8 c){
+  if( pParse->nBlob >= pParse->nBlobAlloc ){
+    jsonBlobExpandAndAppendOneByte(pParse, c);
+  }else{
+    pParse->aBlob[pParse->nBlob++] = c;
+  }
+}
+
+/* Slow version of jsonBlobAppendNode() that first resizes the
+** pParse->aBlob structure.
+*/
+static void jsonBlobAppendNode(JsonParse*,u8,u32,const void*);
+static SQLITE_NOINLINE void jsonBlobExpandAndAppendNode(
+  JsonParse *pParse,
+  u8 eType,
+  u32 szPayload,
+  const void *aPayload
+){
+  if( jsonBlobExpand(pParse, pParse->nBlob+szPayload+9) ) return;
+  jsonBlobAppendNode(pParse, eType, szPayload, aPayload);
+}
+
+
+/* Append an node type byte together with the payload size and
+** possibly also the payload.
+**
+** If aPayload is not NULL, then it is a pointer to the payload which
+** is also appended.  If aPayload is NULL, the pParse->aBlob[] array
+** is resized (if necessary) so that it is big enough to hold the
+** payload, but the payload is not appended and pParse->nBlob is left
+** pointing to where the first byte of payload will eventually be.
+*/
+static void jsonBlobAppendNode(
+  JsonParse *pParse,          /* The JsonParse object under construction */
+  u8 eType,                   /* Node type.  One of JSONB_* */
+  u32 szPayload,              /* Number of bytes of payload */
+  const void *aPayload        /* The payload.  Might be NULL */
+){
+  u8 *a;
+  if( pParse->nBlob+szPayload+9 > pParse->nBlobAlloc ){
+    jsonBlobExpandAndAppendNode(pParse,eType,szPayload,aPayload);
+    return;
+  }
+  assert( pParse->aBlob!=0 );
+  a = &pParse->aBlob[pParse->nBlob];
+  if( szPayload<=11 ){
+    a[0] = eType | (szPayload<<4);
+    pParse->nBlob += 1;
+  }else if( szPayload<=0xff ){
+    a[0] = eType | 0xc0;
+    a[1] = szPayload & 0xff;
+    pParse->nBlob += 2;
+  }else if( szPayload<=0xffff ){
+    a[0] = eType | 0xd0;
+    a[1] = (szPayload >> 8) & 0xff;
+    a[2] = szPayload & 0xff;
+    pParse->nBlob += 3;
+  }else{
+    a[0] = eType | 0xe0;
+    a[1] = (szPayload >> 24) & 0xff;
+    a[2] = (szPayload >> 16) & 0xff;
+    a[3] = (szPayload >> 8) & 0xff;
+    a[4] = szPayload & 0xff;
+    pParse->nBlob += 5;
+  }
+  if( aPayload ){
+    pParse->nBlob += szPayload;
+    memcpy(&pParse->aBlob[pParse->nBlob-szPayload], aPayload, szPayload);
+  }
+}
+
+/* Change the payload size for the node at index i to be szPayload.
+*/
+static int jsonBlobChangePayloadSize(
+  JsonParse *pParse,
+  u32 i,
+  u32 szPayload
+){
+  u8 *a;
+  u8 szType;
+  u8 nExtra;
+  u8 nNeeded;
+  int delta;
+  if( pParse->oom ) return 0;
+  a = &pParse->aBlob[i];
+  szType = a[0]>>4;
+  if( szType<=11 ){
+    nExtra = 0;
+  }else if( szType==12 ){
+    nExtra = 1;
+  }else if( szType==13 ){
+    nExtra = 2;
+  }else{
+    nExtra = 4;
+  }
+  if( szPayload<=11 ){
+    nNeeded = 0;
+  }else if( szPayload<=0xff ){
+    nNeeded = 1;
+  }else if( szPayload<=0xffff ){
+    nNeeded = 2;
+  }else{
+    nNeeded = 4;
+  }
+  delta = nNeeded - nExtra;
+  if( delta ){
+    u32 newSize = pParse->nBlob + delta;
+    if( delta>0 ){
+      if( newSize>pParse->nBlobAlloc && jsonBlobExpand(pParse, newSize) ){
+        return 0;  /* OOM error.  Error state recorded in pParse->oom. */
+      }
+      a = &pParse->aBlob[i];
+      memmove(&a[1+delta], &a[1], pParse->nBlob - (i+1));
+    }else{
+      memmove(&a[1], &a[1-delta], pParse->nBlob - (i+1-delta));
+    }
+    pParse->nBlob = newSize;
+  }
+  if( nNeeded==0 ){
+    a[0] = (a[0] & 0x0f) | (szPayload<<4);
+  }else if( nNeeded==1 ){
+    a[0] = (a[0] & 0x0f) | 0xc0;
+    a[1] = szPayload & 0xff;
+  }else if( nNeeded==2 ){
+    a[0] = (a[0] & 0x0f) | 0xd0;
+    a[1] = (szPayload >> 8) & 0xff;
+    a[2] = szPayload & 0xff;
+  }else{
+    a[0] = (a[0] & 0x0f) | 0xe0;
+    a[1] = (szPayload >> 24) & 0xff;
+    a[2] = (szPayload >> 16) & 0xff;
+    a[3] = (szPayload >> 8) & 0xff;
+    a[4] = szPayload & 0xff;
+  }
+  return delta;
+}
+
+/*
+** If z[0] is 'u' and is followed by exactly 4 hexadecimal character,
+** then set *pOp to JSONB_TEXTJ and return true.  If not, do not make
+** any changes to *pOp and return false.
+*/
+static int jsonIs4HexB(const char *z, int *pOp){
+  if( z[0]!='u' ) return 0;
+  if( !jsonIs4Hex(&z[1]) ) return 0;
+  *pOp = JSONB_TEXTJ;
+  return 1;
+}
+
+/*
+** Check a single element of the JSONB in pParse for validity.
+**
+** The element to be checked starts at offset i and must end at on the
+** last byte before iEnd.
+**
+** Return 0 if everything is correct.  Return the 1-based byte offset of the
+** error if a problem is detected.  (In other words, if the error is at offset
+** 0, return 1).
+*/
+static u32 jsonbValidityCheck(
+  const JsonParse *pParse,    /* Input JSONB.  Only aBlob and nBlob are used */
+  u32 i,                      /* Start of element as pParse->aBlob[i] */
+  u32 iEnd,                   /* One more than the last byte of the element */
+  u32 iDepth                  /* Current nesting depth */
+){
+  u32 n, sz, j, k;
+  const u8 *z;
+  u8 x;
+  if( iDepth>JSON_MAX_DEPTH ) return i+1;
+  sz = 0;
+  n = jsonbPayloadSize(pParse, i, &sz);
+  if( NEVER(n==0) ) return i+1;          /* Checked by caller */
+  if( NEVER(i+n+sz!=iEnd) ) return i+1;  /* Checked by caller */
+  z = pParse->aBlob;
+  x = z[i] & 0x0f;
+  switch( x ){
+    case JSONB_NULL:
+    case JSONB_TRUE:
+    case JSONB_FALSE: {
+      return n+sz==1 ? 0 : i+1;
+    }
+    case JSONB_INT: {
+      if( sz<1 ) return i+1;
+      j = i+n;
+      if( z[j]=='-' ){
+        j++;
+        if( sz<2 ) return i+1;
+      }
+      k = i+n+sz;
+      while( j<k ){
+        if( sqlite3Isdigit(z[j]) ){
+          j++;
+        }else{
+          return j+1;
+        }
+      }
+      return 0;
+    }
+    case JSONB_INT5: {
+      if( sz<3 ) return i+1;
+      j = i+n;
+      if( z[j]=='-' ){
+        if( sz<4 ) return i+1;
+        j++;
+      }
+      if( z[j]!='0' ) return i+1;
+      if( z[j+1]!='x' && z[j+1]!='X' ) return j+2;
+      j += 2;
+      k = i+n+sz;
+      while( j<k ){
+        if( sqlite3Isxdigit(z[j]) ){
+          j++;
+        }else{
+          return j+1;
+        }
+      }
+      return 0;
+    }
+    case JSONB_FLOAT:
+    case JSONB_FLOAT5: {
+      u8 seen = 0;   /* 0: initial.  1: '.' seen  2: 'e' seen */
+      if( sz<2 ) return i+1;
+      j = i+n;
+      k = j+sz;
+      if( z[j]=='-' ){
+        j++;
+        if( sz<3 ) return i+1;
+      }
+      if( z[j]=='.' ){
+        if( x==JSONB_FLOAT ) return j+1;
+        if( !sqlite3Isdigit(z[j+1]) ) return j+1;
+        j += 2;
+        seen = 1;
+      }else if( z[j]=='0' && x==JSONB_FLOAT ){
+        if( j+3>k ) return j+1;
+        if( z[j+1]!='.' && z[j+1]!='e' && z[j+1]!='E' ) return j+1;
+        j++;
+      }
+      for(; j<k; j++){
+        if( sqlite3Isdigit(z[j]) ) continue;
+        if( z[j]=='.' ){
+          if( seen>0 ) return j+1;
+          if( x==JSONB_FLOAT && (j==k-1 || !sqlite3Isdigit(z[j+1])) ){
+            return j+1;
+          }
+          seen = 1;
+          continue;
+        }
+        if( z[j]=='e' || z[j]=='E' ){
+          if( seen==2 ) return j+1;
+          if( j==k-1 ) return j+1;
+          if( z[j+1]=='+' || z[j+1]=='-' ){
+            j++;
+            if( j==k-1 ) return j+1;
+          }
+          seen = 2;
+          continue;
+        }
+        return j+1;
+      }
+      if( seen==0 ) return i+1;
+      return 0;
+    }
+    case JSONB_TEXT: {
+      j = i+n;
+      k = j+sz;
+      while( j<k ){
+        if( !jsonIsOk[z[j]] && z[j]!='\'' ) return j+1;
+        j++;
+      }
+      return 0;
+    }
+    case JSONB_TEXTJ:
+    case JSONB_TEXT5: {
+      j = i+n;
+      k = j+sz;
+      while( j<k ){
+        if( !jsonIsOk[z[j]] && z[j]!='\'' ){
+          if( z[j]=='"' ){
+            if( x==JSONB_TEXTJ ) return j+1;
+          }else if( z[j]<=0x1f ){
+            /* Control characters in JSON5 string literals are ok */
+            if( x==JSONB_TEXTJ ) return j+1;
+          }else if( NEVER(z[j]!='\\') || j+1>=k ){
+            return j+1;
+          }else if( strchr("\"\\/bfnrt",z[j+1])!=0 ){
+            j++;
+          }else if( z[j+1]=='u' ){
+            if( j+5>=k ) return j+1;
+            if( !jsonIs4Hex((const char*)&z[j+2]) ) return j+1;
+            j++;
+          }else if( x!=JSONB_TEXT5 ){
+            return j+1;
+          }else{
+            u32 c = 0;
+            u32 szC = jsonUnescapeOneChar((const char*)&z[j], k-j, &c);
+            if( c==JSON_INVALID_CHAR ) return j+1;
+            j += szC - 1;
+          }
+        }
+        j++;
+      }
+      return 0;
+    }
+    case JSONB_TEXTRAW: {
+      return 0;
+    }
+    case JSONB_ARRAY: {
+      u32 sub;
+      j = i+n;
+      k = j+sz;
+      while( j<k ){
+        sz = 0;
+        n = jsonbPayloadSize(pParse, j, &sz);
+        if( n==0 ) return j+1;
+        if( j+n+sz>k ) return j+1;
+        sub = jsonbValidityCheck(pParse, j, j+n+sz, iDepth+1);
+        if( sub ) return sub;
+        j += n + sz;
+      }
+      assert( j==k );
+      return 0;
+    }
+    case JSONB_OBJECT: {
+      u32 cnt = 0;
+      u32 sub;
+      j = i+n;
+      k = j+sz;
+      while( j<k ){
+        sz = 0;
+        n = jsonbPayloadSize(pParse, j, &sz);
+        if( n==0 ) return j+1;
+        if( j+n+sz>k ) return j+1;
+        if( (cnt & 1)==0 ){
+          x = z[j] & 0x0f;
+          if( x<JSONB_TEXT || x>JSONB_TEXTRAW ) return j+1;
+        }
+        sub = jsonbValidityCheck(pParse, j, j+n+sz, iDepth+1);
+        if( sub ) return sub;
+        cnt++;
+        j += n + sz;
+      }
+      assert( j==k );
+      if( (cnt & 1)!=0 ) return j+1;
+      return 0;
+    }
+    default: {
+      return i+1;
+    }
+  }
+}
+
+/*
+** Translate a single element of JSON text at pParse->zJson[i] into
+** its equivalent binary JSONB representation.  Append the translation into
+** pParse->aBlob[] beginning at pParse->nBlob.  The size of
+** pParse->aBlob[] is increased as necessary.
+**
+** Return the index of the first character past the end of the element parsed,
+** or one of the following special result codes:
+**
+**      0    End of input
+**     -1    Syntax error or OOM
+**     -2    '}' seen   \
+**     -3    ']' seen    \___  For these returns, pParse->iErr is set to
+**     -4    ',' seen    /     the index in zJson[] of the seen character
+**     -5    ':' seen   /
+*/
+static int jsonTranslateTextToBlob(JsonParse *pParse, u32 i){
+  char c;
+  u32 j;
+  u32 iThis, iStart;
+  int x;
+  u8 t;
+  const char *z = pParse->zJson;
+json_parse_restart:
+  switch( (u8)z[i] ){
+  case '{': {
+    /* Parse object */
+    iThis = pParse->nBlob;
+    jsonBlobAppendNode(pParse, JSONB_OBJECT, pParse->nJson-i, 0);
+    if( ++pParse->iDepth > JSON_MAX_DEPTH ){
+      pParse->iErr = i;
+      return -1;
+    }
+    iStart = pParse->nBlob;
+    for(j=i+1;;j++){
+      u32 iBlob = pParse->nBlob;
+      x = jsonTranslateTextToBlob(pParse, j);
+      if( x<=0 ){
+        int op;
+        if( x==(-2) ){
+          j = pParse->iErr;
+          if( pParse->nBlob!=(u32)iStart ) pParse->hasNonstd = 1;
+          break;
+        }
+        j += json5Whitespace(&z[j]);
+        op = JSONB_TEXT;
+        if( sqlite3JsonId1(z[j])
+         || (z[j]=='\\' && jsonIs4HexB(&z[j+1], &op))
+        ){
+          int k = j+1;
+          while( (sqlite3JsonId2(z[k]) && json5Whitespace(&z[k])==0)
+            || (z[k]=='\\' && jsonIs4HexB(&z[k+1], &op))
+          ){
+            k++;
+          }
+          assert( iBlob==pParse->nBlob );
+          jsonBlobAppendNode(pParse, op, k-j, &z[j]);
+          pParse->hasNonstd = 1;
+          x = k;
+        }else{
+          if( x!=-1 ) pParse->iErr = j;
+          return -1;
+        }
+      }
+      if( pParse->oom ) return -1;
+      t = pParse->aBlob[iBlob] & 0x0f;
+      if( t<JSONB_TEXT || t>JSONB_TEXTRAW ){
+        pParse->iErr = j;
+        return -1;
+      }
+      j = x;
+      if( z[j]==':' ){
+        j++;
+      }else{
+        if( jsonIsspace(z[j]) ){
+          /* strspn() is not helpful here */
+          do{ j++; }while( jsonIsspace(z[j]) );
+          if( z[j]==':' ){
+            j++;
+            goto parse_object_value;
+          }
+        }
+        x = jsonTranslateTextToBlob(pParse, j);
+        if( x!=(-5) ){
+          if( x!=(-1) ) pParse->iErr = j;
+          return -1;
+        }
+        j = pParse->iErr+1;
+      }
+    parse_object_value:
+      x = jsonTranslateTextToBlob(pParse, j);
+      if( x<=0 ){
+        if( x!=(-1) ) pParse->iErr = j;
+        return -1;
+      }
+      j = x;
+      if( z[j]==',' ){
+        continue;
+      }else if( z[j]=='}' ){
+        break;
+      }else{
+        if( jsonIsspace(z[j]) ){
+          j += 1 + (u32)strspn(&z[j+1], jsonSpaces);
+          if( z[j]==',' ){
+            continue;
+          }else if( z[j]=='}' ){
+            break;
+          }
+        }
+        x = jsonTranslateTextToBlob(pParse, j);
+        if( x==(-4) ){
+          j = pParse->iErr;
+          continue;
+        }
+        if( x==(-2) ){
+          j = pParse->iErr;
+          break;
+        }
+      }
+      pParse->iErr = j;
+      return -1;
+    }
+    jsonBlobChangePayloadSize(pParse, iThis, pParse->nBlob - iStart);
+    pParse->iDepth--;
+    return j+1;
+  }
+  case '[': {
+    /* Parse array */
+    iThis = pParse->nBlob;
+    assert( i<=(u32)pParse->nJson );
+    jsonBlobAppendNode(pParse, JSONB_ARRAY, pParse->nJson - i, 0);
+    iStart = pParse->nBlob;
+    if( pParse->oom ) return -1;
+    if( ++pParse->iDepth > JSON_MAX_DEPTH ){
+      pParse->iErr = i;
+      return -1;
+    }
+    for(j=i+1;;j++){
+      x = jsonTranslateTextToBlob(pParse, j);
+      if( x<=0 ){
+        if( x==(-3) ){
+          j = pParse->iErr;
+          if( pParse->nBlob!=iStart ) pParse->hasNonstd = 1;
+          break;
+        }
+        if( x!=(-1) ) pParse->iErr = j;
+        return -1;
+      }
+      j = x;
+      if( z[j]==',' ){
+        continue;
+      }else if( z[j]==']' ){
+        break;
+      }else{
+        if( jsonIsspace(z[j]) ){
+          j += 1 + (u32)strspn(&z[j+1], jsonSpaces);
+          if( z[j]==',' ){
+            continue;
+          }else if( z[j]==']' ){
+            break;
+          }
+        }
+        x = jsonTranslateTextToBlob(pParse, j);
+        if( x==(-4) ){
+          j = pParse->iErr;
+          continue;
+        }
+        if( x==(-3) ){
+          j = pParse->iErr;
+          break;
+        }
+      }
+      pParse->iErr = j;
+      return -1;
+    }
+    jsonBlobChangePayloadSize(pParse, iThis, pParse->nBlob - iStart);
+    pParse->iDepth--;
+    return j+1;
+  }
+  case '\'': {
+    u8 opcode;
+    char cDelim;
+    pParse->hasNonstd = 1;
+    opcode = JSONB_TEXT;
+    goto parse_string;
+  case '"':
+    /* Parse string */
+    opcode = JSONB_TEXT;
+  parse_string:
+    cDelim = z[i];
+    j = i+1;
+    while( 1 /*exit-by-break*/ ){
+      if( jsonIsOk[(u8)z[j]] ){
+        if( !jsonIsOk[(u8)z[j+1]] ){
+          j += 1;
+        }else if( !jsonIsOk[(u8)z[j+2]] ){
+          j += 2;
+        }else{
+          j += 3;
+          continue;
+        }
+      }
+      c = z[j];
+      if( c==cDelim ){
+        break;
+      }else if( c=='\\' ){
+        c = z[++j];
+        if( c=='"' || c=='\\' || c=='/' || c=='b' || c=='f'
+           || c=='n' || c=='r' || c=='t'
+           || (c=='u' && jsonIs4Hex(&z[j+1])) ){
+          if( opcode==JSONB_TEXT ) opcode = JSONB_TEXTJ;
+        }else if( c=='\'' || c=='0' || c=='v' || c=='\n'
+           || (0xe2==(u8)c && 0x80==(u8)z[j+1]
+                && (0xa8==(u8)z[j+2] || 0xa9==(u8)z[j+2]))
+           || (c=='x' && jsonIs2Hex(&z[j+1])) ){
+          opcode = JSONB_TEXT5;
+          pParse->hasNonstd = 1;
+        }else if( c=='\r' ){
+          if( z[j+1]=='\n' ) j++;
+          opcode = JSONB_TEXT5;
+          pParse->hasNonstd = 1;
+        }else{
+          pParse->iErr = j;
+          return -1;
+        }
+      }else if( c<=0x1f ){
+        if( c==0 ){
+          pParse->iErr = j;
+          return -1;
+        }
+        /* Control characters are not allowed in canonical JSON string
+        ** literals, but are allowed in JSON5 string literals. */
+        opcode = JSONB_TEXT5;
+        pParse->hasNonstd = 1;
+      }else if( c=='"' ){
+        opcode = JSONB_TEXT5;
+      }
+      j++;
+    }
+    jsonBlobAppendNode(pParse, opcode, j-1-i, &z[i+1]);
+    return j+1;
+  }
+  case 't': {
+    if( strncmp(z+i,"true",4)==0 && !sqlite3Isalnum(z[i+4]) ){
+      jsonBlobAppendOneByte(pParse, JSONB_TRUE);
+      return i+4;
+    }
+    pParse->iErr = i;
+    return -1;
+  }
+  case 'f': {
+    if( strncmp(z+i,"false",5)==0 && !sqlite3Isalnum(z[i+5]) ){
+      jsonBlobAppendOneByte(pParse, JSONB_FALSE);
+      return i+5;
+    }
+    pParse->iErr = i;
+    return -1;
+  }
+  case '+': {
+    u8 seenE;
+    pParse->hasNonstd = 1;
+    t = 0x00;            /* Bit 0x01:  JSON5.   Bit 0x02:  FLOAT */
+    goto parse_number;
+  case '.':
+    if( sqlite3Isdigit(z[i+1]) ){
+      pParse->hasNonstd = 1;
+      t = 0x03;          /* Bit 0x01:  JSON5.   Bit 0x02:  FLOAT */
+      seenE = 0;
+      goto parse_number_2;
+    }
+    pParse->iErr = i;
+    return -1;
+  case '-':
+  case '0':
+  case '1':
+  case '2':
+  case '3':
+  case '4':
+  case '5':
+  case '6':
+  case '7':
+  case '8':
+  case '9':
+    /* Parse number */
+    t = 0x00;            /* Bit 0x01:  JSON5.   Bit 0x02:  FLOAT */
+  parse_number:
+    seenE = 0;
+    assert( '-' < '0' );
+    assert( '+' < '0' );
+    assert( '.' < '0' );
+    c = z[i];
+
+    if( c<='0' ){
+      if( c=='0' ){
+        if( (z[i+1]=='x' || z[i+1]=='X') && sqlite3Isxdigit(z[i+2]) ){
+          assert( t==0x00 );
+          pParse->hasNonstd = 1;
+          t = 0x01;
+          for(j=i+3; sqlite3Isxdigit(z[j]); j++){}
+          goto parse_number_finish;
+        }else if( sqlite3Isdigit(z[i+1]) ){
+          pParse->iErr = i+1;
+          return -1;
+        }
+      }else{
+        if( !sqlite3Isdigit(z[i+1]) ){
+          /* JSON5 allows for "+Infinity" and "-Infinity" using exactly
+          ** that case.  SQLite also allows these in any case and it allows
+          ** "+inf" and "-inf". */
+          if( (z[i+1]=='I' || z[i+1]=='i')
+           && sqlite3StrNICmp(&z[i+1], "inf",3)==0
+          ){
+            pParse->hasNonstd = 1;
+            if( z[i]=='-' ){
+              jsonBlobAppendNode(pParse, JSONB_FLOAT, 6, "-9e999");
+            }else{
+              jsonBlobAppendNode(pParse, JSONB_FLOAT, 5, "9e999");
+            }
+            return i + (sqlite3StrNICmp(&z[i+4],"inity",5)==0 ? 9 : 4);
+          }
+          if( z[i+1]=='.' ){
+            pParse->hasNonstd = 1;
+            t |= 0x01;
+            goto parse_number_2;
+          }
+          pParse->iErr = i;
+          return -1;
+        }
+        if( z[i+1]=='0' ){
+          if( sqlite3Isdigit(z[i+2]) ){
+            pParse->iErr = i+1;
+            return -1;
+          }else if( (z[i+2]=='x' || z[i+2]=='X') && sqlite3Isxdigit(z[i+3]) ){
+            pParse->hasNonstd = 1;
+            t |= 0x01;
+            for(j=i+4; sqlite3Isxdigit(z[j]); j++){}
+            goto parse_number_finish;
+          }
+        }
+      }
+    }
+
+  parse_number_2:
+    for(j=i+1;; j++){
+      c = z[j];
+      if( sqlite3Isdigit(c) ) continue;
+      if( c=='.' ){
+        if( (t & 0x02)!=0 ){
+          pParse->iErr = j;
+          return -1;
+        }
+        t |= 0x02;
+        continue;
+      }
+      if( c=='e' || c=='E' ){
+        if( z[j-1]<'0' ){
+          if( ALWAYS(z[j-1]=='.') && ALWAYS(j-2>=i) && sqlite3Isdigit(z[j-2]) ){
+            pParse->hasNonstd = 1;
+            t |= 0x01;
+          }else{
+            pParse->iErr = j;
+            return -1;
+          }
+        }
+        if( seenE ){
+          pParse->iErr = j;
+          return -1;
+        }
+        t |= 0x02;
+        seenE = 1;
+        c = z[j+1];
+        if( c=='+' || c=='-' ){
+          j++;
+          c = z[j+1];
+        }
+        if( c<'0' || c>'9' ){
+          pParse->iErr = j;
+          return -1;
+        }
+        continue;
+      }
+      break;
+    }
+    if( z[j-1]<'0' ){
+      if( ALWAYS(z[j-1]=='.') && ALWAYS(j-2>=i) && sqlite3Isdigit(z[j-2]) ){
+        pParse->hasNonstd = 1;
+        t |= 0x01;
+      }else{
+        pParse->iErr = j;
+        return -1;
+      }
+    }
+  parse_number_finish:
+    assert( JSONB_INT+0x01==JSONB_INT5 );
+    assert( JSONB_FLOAT+0x01==JSONB_FLOAT5 );
+    assert( JSONB_INT+0x02==JSONB_FLOAT );
+    if( z[i]=='+' ) i++;
+    jsonBlobAppendNode(pParse, JSONB_INT+t, j-i, &z[i]);
+    return j;
+  }
+  case '}': {
+    pParse->iErr = i;
+    return -2;  /* End of {...} */
+  }
+  case ']': {
+    pParse->iErr = i;
+    return -3;  /* End of [...] */
+  }
+  case ',': {
+    pParse->iErr = i;
+    return -4;  /* List separator */
+  }
+  case ':': {
+    pParse->iErr = i;
+    return -5;  /* Object label/value separator */
+  }
+  case 0: {
+    return 0;   /* End of file */
+  }
+  case 0x09:
+  case 0x0a:
+  case 0x0d:
+  case 0x20: {
+    i += 1 + (u32)strspn(&z[i+1], jsonSpaces);
+    goto json_parse_restart;
+  }
+  case 0x0b:
+  case 0x0c:
+  case '/':
+  case 0xc2:
+  case 0xe1:
+  case 0xe2:
+  case 0xe3:
+  case 0xef: {
+    j = json5Whitespace(&z[i]);
+    if( j>0 ){
+      i += j;
+      pParse->hasNonstd = 1;
+      goto json_parse_restart;
+    }
+    pParse->iErr = i;
+    return -1;
+  }
+  case 'n': {
+    if( strncmp(z+i,"null",4)==0 && !sqlite3Isalnum(z[i+4]) ){
+      jsonBlobAppendOneByte(pParse, JSONB_NULL);
+      return i+4;
+    }
+    /* fall-through into the default case that checks for NaN */
+    /* no break */ deliberate_fall_through
+  }
+  default: {
+    u32 k;
+    int nn;
+    c = z[i];
+    for(k=0; k<sizeof(aNanInfName)/sizeof(aNanInfName[0]); k++){
+      if( c!=aNanInfName[k].c1 && c!=aNanInfName[k].c2 ) continue;
+      nn = aNanInfName[k].n;
+      if( sqlite3StrNICmp(&z[i], aNanInfName[k].zMatch, nn)!=0 ){
+        continue;
+      }
+      if( sqlite3Isalnum(z[i+nn]) ) continue;
+      if( aNanInfName[k].eType==JSONB_FLOAT ){
+        jsonBlobAppendNode(pParse, JSONB_FLOAT, 5, "9e999");
+      }else{
+        jsonBlobAppendOneByte(pParse, JSONB_NULL);
+      }
+      pParse->hasNonstd = 1;
+      return i + nn;
+    }
+    pParse->iErr = i;
+    return -1;  /* Syntax error */
+  }
+  } /* End switch(z[i]) */
+}
+
+
+/*
+** Parse a complete JSON string.  Return 0 on success or non-zero if there
+** are any errors.  If an error occurs, free all memory held by pParse,
+** but not pParse itself.
+**
+** pParse must be initialized to an empty parse object prior to calling
+** this routine.
+*/
+static int jsonConvertTextToBlob(
+  JsonParse *pParse,           /* Initialize and fill this JsonParse object */
+  sqlite3_context *pCtx        /* Report errors here */
+){
+  int i;
+  const char *zJson = pParse->zJson;
+  i = jsonTranslateTextToBlob(pParse, 0);
+  if( pParse->oom ) i = -1;
+  if( i>0 ){
+#ifdef SQLITE_DEBUG
+    assert( pParse->iDepth==0 );
+    if( sqlite3Config.bJsonSelfcheck ){
+      assert( jsonbValidityCheck(pParse, 0, pParse->nBlob, 0)==0 );
+    }
+#endif
+    while( jsonIsspace(zJson[i]) ) i++;
+    if( zJson[i] ){
+      i += json5Whitespace(&zJson[i]);
+      if( zJson[i] ){
+        if( pCtx ) sqlite3_result_error(pCtx, "malformed JSON", -1);
+        jsonParseReset(pParse);
+        return 1;
+      }
+      pParse->hasNonstd = 1;
+    }
+  }
+  if( i<=0 ){
+    if( pCtx!=0 ){
+      if( pParse->oom ){
+        sqlite3_result_error_nomem(pCtx);
+      }else{
+        sqlite3_result_error(pCtx, "malformed JSON", -1);
+      }
+    }
+    jsonParseReset(pParse);
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** The input string pStr is a well-formed JSON text string.  Convert
+** this into the JSONB format and make it the return value of the
+** SQL function.
+*/
+static void jsonReturnStringAsBlob(JsonString *pStr){
+  JsonParse px;
+  memset(&px, 0, sizeof(px));
+  jsonStringTerminate(pStr);
+  if( pStr->eErr ){
+    sqlite3_result_error_nomem(pStr->pCtx);
+    return;
+  }
+  px.zJson = pStr->zBuf;
+  px.nJson = pStr->nUsed;
+  px.db = sqlite3_context_db_handle(pStr->pCtx);
+  (void)jsonTranslateTextToBlob(&px, 0);
+  if( px.oom ){
+    sqlite3DbFree(px.db, px.aBlob);
+    sqlite3_result_error_nomem(pStr->pCtx);
+  }else{
+    assert( px.nBlobAlloc>0 );
+    assert( !px.bReadOnly );
+    sqlite3_result_blob(pStr->pCtx, px.aBlob, px.nBlob, SQLITE_DYNAMIC);
+  }
+}
+
+/* The byte at index i is a node type-code.  This routine
+** determines the payload size for that node and writes that
+** payload size in to *pSz.  It returns the offset from i to the
+** beginning of the payload.  Return 0 on error.
+*/
+static u32 jsonbPayloadSize(const JsonParse *pParse, u32 i, u32 *pSz){
+  u8 x;
+  u32 sz;
+  u32 n;
+  if( NEVER(i>pParse->nBlob) ){
+    *pSz = 0;
+    return 0;
+  }
+  x = pParse->aBlob[i]>>4;
+  if( x<=11 ){
+    sz = x;
+    n = 1;
+  }else if( x==12 ){
+    if( i+1>=pParse->nBlob ){
+      *pSz = 0;
+      return 0;
+    }
+    sz = pParse->aBlob[i+1];
+    n = 2;
+  }else if( x==13 ){
+    if( i+2>=pParse->nBlob ){
+      *pSz = 0;
+      return 0;
+    }
+    sz = (pParse->aBlob[i+1]<<8) + pParse->aBlob[i+2];
+    n = 3;
+  }else if( x==14 ){
+    if( i+4>=pParse->nBlob ){
+      *pSz = 0;
+      return 0;
+    }
+    sz = ((u32)pParse->aBlob[i+1]<<24) + (pParse->aBlob[i+2]<<16) +
+         (pParse->aBlob[i+3]<<8) + pParse->aBlob[i+4];
+    n = 5;
+  }else{
+    if( i+8>=pParse->nBlob
+     || pParse->aBlob[i+1]!=0
+     || pParse->aBlob[i+2]!=0
+     || pParse->aBlob[i+3]!=0
+     || pParse->aBlob[i+4]!=0
+    ){
+      *pSz = 0;
+      return 0;
+    }
+    sz = (pParse->aBlob[i+5]<<24) + (pParse->aBlob[i+6]<<16) +
+         (pParse->aBlob[i+7]<<8) + pParse->aBlob[i+8];
+    n = 9;
+  }
+  if( (i64)i+sz+n > pParse->nBlob
+   && (i64)i+sz+n > pParse->nBlob-pParse->delta
+  ){
+    sz = 0;
+    n = 0;
+  }
+  *pSz = sz;
+  return n;
+}
+
+
+/*
+** Translate the binary JSONB representation of JSON beginning at
+** pParse->aBlob[i] into a JSON text string.  Append the JSON
+** text onto the end of pOut.  Return the index in pParse->aBlob[]
+** of the first byte past the end of the element that is translated.
+**
+** If an error is detected in the BLOB input, the pOut->eErr flag
+** might get set to JSTRING_MALFORMED.  But not all BLOB input errors
+** are detected.  So a malformed JSONB input might either result
+** in an error, or in incorrect JSON.
+**
+** The pOut->eErr JSTRING_OOM flag is set on a OOM.
+*/
+static u32 jsonTranslateBlobToText(
+  const JsonParse *pParse,       /* the complete parse of the JSON */
+  u32 i,                         /* Start rendering at this index */
+  JsonString *pOut               /* Write JSON here */
+){
+  u32 sz, n, j, iEnd;
+
+  n = jsonbPayloadSize(pParse, i, &sz);
+  if( n==0 ){
+    pOut->eErr |= JSTRING_MALFORMED;
+    return pParse->nBlob+1;
+  }
+  switch( pParse->aBlob[i] & 0x0f ){
+    case JSONB_NULL: {
+      jsonAppendRawNZ(pOut, "null", 4);
+      return i+1;
+    }
+    case JSONB_TRUE: {
+      jsonAppendRawNZ(pOut, "true", 4);
+      return i+1;
+    }
+    case JSONB_FALSE: {
+      jsonAppendRawNZ(pOut, "false", 5);
+      return i+1;
+    }
+    case JSONB_INT:
+    case JSONB_FLOAT: {
+      if( sz==0 ) goto malformed_jsonb;
+      jsonAppendRaw(pOut, (const char*)&pParse->aBlob[i+n], sz);
+      break;
+    }
+    case JSONB_INT5: {  /* Integer literal in hexadecimal notation */
+      u32 k = 2;
+      sqlite3_uint64 u = 0;
+      const char *zIn = (const char*)&pParse->aBlob[i+n];
+      int bOverflow = 0;
+      if( sz==0 ) goto malformed_jsonb;
+      if( zIn[0]=='-' ){
+        jsonAppendChar(pOut, '-');
+        k++;
+      }else if( zIn[0]=='+' ){
+        k++;
+      }
+      for(; k<sz; k++){
+        if( !sqlite3Isxdigit(zIn[k]) ){
+          pOut->eErr |= JSTRING_MALFORMED;
+          break;
+        }else if( (u>>60)!=0 ){
+          bOverflow = 1;
+        }else{
+          u = u*16 + sqlite3HexToInt(zIn[k]);
+        }
+      }
+      jsonPrintf(100,pOut,bOverflow?"9.0e999":"%llu", u);
+      break;
+    }
+    case JSONB_FLOAT5: { /* Float literal missing digits beside "." */
+      u32 k = 0;
+      const char *zIn = (const char*)&pParse->aBlob[i+n];
+      if( sz==0 ) goto malformed_jsonb;
+      if( zIn[0]=='-' ){
+        jsonAppendChar(pOut, '-');
+        k++;
+      }
+      if( zIn[k]=='.' ){
+        jsonAppendChar(pOut, '0');
+      }
+      for(; k<sz; k++){
+        jsonAppendChar(pOut, zIn[k]);
+        if( zIn[k]=='.' && (k+1==sz || !sqlite3Isdigit(zIn[k+1])) ){
+          jsonAppendChar(pOut, '0');
+        }
+      }
+      break;
+    }
+    case JSONB_TEXT:
+    case JSONB_TEXTJ: {
+      jsonAppendChar(pOut, '"');
+      jsonAppendRaw(pOut, (const char*)&pParse->aBlob[i+n], sz);
+      jsonAppendChar(pOut, '"');
+      break;
+    }
+    case JSONB_TEXT5: {
+      const char *zIn;
+      u32 k;
+      u32 sz2 = sz;
+      zIn = (const char*)&pParse->aBlob[i+n];
+      jsonAppendChar(pOut, '"');
+      while( sz2>0 ){
+        for(k=0; k<sz2 && (jsonIsOk[(u8)zIn[k]] || zIn[k]=='\''); k++){}
+        if( k>0 ){
+          jsonAppendRawNZ(pOut, zIn, k);
+          if( k>=sz2 ){
+            break;
+          }
+          zIn += k;
+          sz2 -= k;
+        }
+        if( zIn[0]=='"' ){
+          jsonAppendRawNZ(pOut, "\\\"", 2);
+          zIn++;
+          sz2--;
+          continue;
+        }
+        if( zIn[0]<=0x1f ){
+          if( pOut->nUsed+7>pOut->nAlloc && jsonStringGrow(pOut,7) ) break;
+          jsonAppendControlChar(pOut, zIn[0]);
+          zIn++;
+          sz2--;
+          continue;
+        }
+        assert( zIn[0]=='\\' );
+        assert( sz2>=1 );
+        if( sz2<2 ){
+          pOut->eErr |= JSTRING_MALFORMED;
+          break;
+        }
+        switch( (u8)zIn[1] ){
+          case '\'':
+            jsonAppendChar(pOut, '\'');
+            break;
+          case 'v':
+            jsonAppendRawNZ(pOut, "\\u0009", 6);
+            break;
+          case 'x':
+            if( sz2<4 ){
+              pOut->eErr |= JSTRING_MALFORMED;
+              sz2 = 2;
+              break;
+            }
+            jsonAppendRawNZ(pOut, "\\u00", 4);
+            jsonAppendRawNZ(pOut, &zIn[2], 2);
+            zIn += 2;
+            sz2 -= 2;
+            break;
+          case '0':
+            jsonAppendRawNZ(pOut, "\\u0000", 6);
+            break;
+          case '\r':
+            if( sz2>2 && zIn[2]=='\n' ){
+              zIn++;
+              sz2--;
+            }
+            break;
+          case '\n':
+            break;
+          case 0xe2:
+            /* '\' followed by either U+2028 or U+2029 is ignored as
+            ** whitespace.  Not that in UTF8, U+2028 is 0xe2 0x80 0x29.
+            ** U+2029 is the same except for the last byte */
+            if( sz2<4
+             || 0x80!=(u8)zIn[2]
+             || (0xa8!=(u8)zIn[3] && 0xa9!=(u8)zIn[3])
+            ){
+              pOut->eErr |= JSTRING_MALFORMED;
+              sz2 = 2;
+              break;
+            }
+            zIn += 2;
+            sz2 -= 2;
+            break;
+          default:
+            jsonAppendRawNZ(pOut, zIn, 2);
+            break;
+        }
+        assert( sz2>=2 );
+        zIn += 2;
+        sz2 -= 2;
+      }
+      jsonAppendChar(pOut, '"');
+      break;
+    }
+    case JSONB_TEXTRAW: {
+      jsonAppendString(pOut, (const char*)&pParse->aBlob[i+n], sz);
+      break;
+    }
+    case JSONB_ARRAY: {
+      jsonAppendChar(pOut, '[');
+      j = i+n;
+      iEnd = j+sz;
+      while( j<iEnd && pOut->eErr==0 ){
+        j = jsonTranslateBlobToText(pParse, j, pOut);
+        jsonAppendChar(pOut, ',');
+      }
+      if( j>iEnd ) pOut->eErr |= JSTRING_MALFORMED;
+      if( sz>0 ) jsonStringTrimOneChar(pOut);
+      jsonAppendChar(pOut, ']');
+      break;
+    }
+    case JSONB_OBJECT: {
+      int x = 0;
+      jsonAppendChar(pOut, '{');
+      j = i+n;
+      iEnd = j+sz;
+      while( j<iEnd && pOut->eErr==0 ){
+        j = jsonTranslateBlobToText(pParse, j, pOut);
+        jsonAppendChar(pOut, (x++ & 1) ? ',' : ':');
+      }
+      if( (x & 1)!=0 || j>iEnd ) pOut->eErr |= JSTRING_MALFORMED;
+      if( sz>0 ) jsonStringTrimOneChar(pOut);
+      jsonAppendChar(pOut, '}');
+      break;
+    }
+
+    default: {
+      malformed_jsonb:
+      pOut->eErr |= JSTRING_MALFORMED;
+      break;
+    }
+  }
+  return i+n+sz;
+}
+
+/* Context for recursion of json_pretty()
+*/
+typedef struct JsonPretty JsonPretty;
+struct JsonPretty {
+  JsonParse *pParse;        /* The BLOB being rendered */
+  JsonString *pOut;         /* Generate pretty output into this string */
+  const char *zIndent;      /* Use this text for indentation */
+  u32 szIndent;             /* Bytes in zIndent[] */
+  u32 nIndent;              /* Current level of indentation */
+};
+
+/* Append indentation to the pretty JSON under construction */
+static void jsonPrettyIndent(JsonPretty *pPretty){
+  u32 jj;
+  for(jj=0; jj<pPretty->nIndent; jj++){
+    jsonAppendRaw(pPretty->pOut, pPretty->zIndent, pPretty->szIndent);
+  }
+}
+
+/*
+** Translate the binary JSONB representation of JSON beginning at
+** pParse->aBlob[i] into a JSON text string.  Append the JSON
+** text onto the end of pOut.  Return the index in pParse->aBlob[]
+** of the first byte past the end of the element that is translated.
+**
+** This is a variant of jsonTranslateBlobToText() that "pretty-prints"
+** the output.  Extra whitespace is inserted to make the JSON easier
+** for humans to read.
+**
+** If an error is detected in the BLOB input, the pOut->eErr flag
+** might get set to JSTRING_MALFORMED.  But not all BLOB input errors
+** are detected.  So a malformed JSONB input might either result
+** in an error, or in incorrect JSON.
+**
+** The pOut->eErr JSTRING_OOM flag is set on a OOM.
+*/
+static u32 jsonTranslateBlobToPrettyText(
+  JsonPretty *pPretty,       /* Pretty-printing context */
+  u32 i                      /* Start rendering at this index */
+){
+  u32 sz, n, j, iEnd;
+  const JsonParse *pParse = pPretty->pParse;
+  JsonString *pOut = pPretty->pOut;
+  n = jsonbPayloadSize(pParse, i, &sz);
+  if( n==0 ){
+    pOut->eErr |= JSTRING_MALFORMED;
+    return pParse->nBlob+1;
+  }
+  switch( pParse->aBlob[i] & 0x0f ){
+    case JSONB_ARRAY: {
+      j = i+n;
+      iEnd = j+sz;
+      jsonAppendChar(pOut, '[');
+      if( j<iEnd ){
+        jsonAppendChar(pOut, '\n');
+        pPretty->nIndent++;
+        while( pOut->eErr==0 ){
+          jsonPrettyIndent(pPretty);
+          j = jsonTranslateBlobToPrettyText(pPretty, j);
+          if( j>=iEnd ) break;
+          jsonAppendRawNZ(pOut, ",\n", 2);
+        }
+        jsonAppendChar(pOut, '\n');
+        pPretty->nIndent--;
+        jsonPrettyIndent(pPretty);
+      }
+      jsonAppendChar(pOut, ']');
+      i = iEnd;
+      break;
+    }
+    case JSONB_OBJECT: {
+      j = i+n;
+      iEnd = j+sz;
+      jsonAppendChar(pOut, '{');
+      if( j<iEnd ){
+        jsonAppendChar(pOut, '\n');
+        pPretty->nIndent++;
+        while( pOut->eErr==0 ){
+          jsonPrettyIndent(pPretty);
+          j = jsonTranslateBlobToText(pParse, j, pOut);
+          if( j>iEnd ){
+            pOut->eErr |= JSTRING_MALFORMED;
+            break;
+          }
+          jsonAppendRawNZ(pOut, ": ", 2);
+          j = jsonTranslateBlobToPrettyText(pPretty, j);
+          if( j>=iEnd ) break;
+          jsonAppendRawNZ(pOut, ",\n", 2);
+        }
+        jsonAppendChar(pOut, '\n');
+        pPretty->nIndent--;
+        jsonPrettyIndent(pPretty);
+      }
+      jsonAppendChar(pOut, '}');
+      i = iEnd;
+      break;
+    }
+    default: {
+      i = jsonTranslateBlobToText(pParse, i, pOut);
+      break;
+    }
+  }
+  return i;
+}
+
+
+/* Return true if the input pJson
+**
+** For performance reasons, this routine does not do a detailed check of the
+** input BLOB to ensure that it is well-formed.  Hence, false positives are
+** possible.  False negatives should never occur, however.
+*/
+static int jsonFuncArgMightBeBinary(sqlite3_value *pJson){
+  u32 sz, n;
+  const u8 *aBlob;
+  int nBlob;
+  JsonParse s;
+  if( sqlite3_value_type(pJson)!=SQLITE_BLOB ) return 0;
+  aBlob = sqlite3_value_blob(pJson);
+  nBlob = sqlite3_value_bytes(pJson);
+  if( nBlob<1 ) return 0;
+  if( NEVER(aBlob==0) || (aBlob[0] & 0x0f)>JSONB_OBJECT ) return 0;
+  memset(&s, 0, sizeof(s));
+  s.aBlob = (u8*)aBlob;
+  s.nBlob = nBlob;
+  n = jsonbPayloadSize(&s, 0, &sz);
+  if( n==0 ) return 0;
+  if( sz+n!=(u32)nBlob ) return 0;
+  if( (aBlob[0] & 0x0f)<=JSONB_FALSE && sz>0 ) return 0;
+  return sz+n==(u32)nBlob;
+}
+
+/*
+** Given that a JSONB_ARRAY object starts at offset i, return
+** the number of entries in that array.
+*/
+static u32 jsonbArrayCount(JsonParse *pParse, u32 iRoot){
+  u32 n, sz, i, iEnd;
+  u32 k = 0;
+  n = jsonbPayloadSize(pParse, iRoot, &sz);
+  iEnd = iRoot+n+sz;
+  for(i=iRoot+n; n>0 && i<iEnd; i+=sz+n, k++){
+    n = jsonbPayloadSize(pParse, i, &sz);
+  }
+  return k;
+}
+
+/*
+** Edit the payload size of the element at iRoot by the amount in
+** pParse->delta.
+*/
+static void jsonAfterEditSizeAdjust(JsonParse *pParse, u32 iRoot){
+  u32 sz = 0;
+  u32 nBlob;
+  assert( pParse->delta!=0 );
+  assert( pParse->nBlobAlloc >= pParse->nBlob );
+  nBlob = pParse->nBlob;
+  pParse->nBlob = pParse->nBlobAlloc;
+  (void)jsonbPayloadSize(pParse, iRoot, &sz);
+  pParse->nBlob = nBlob;
+  sz += pParse->delta;
+  pParse->delta += jsonBlobChangePayloadSize(pParse, iRoot, sz);
+}
+
+/*
+** Modify the JSONB blob at pParse->aBlob by removing nDel bytes of
+** content beginning at iDel, and replacing them with nIns bytes of
+** content given by aIns.
+**
+** nDel may be zero, in which case no bytes are removed.  But iDel is
+** still important as new bytes will be insert beginning at iDel.
+**
+** aIns may be zero, in which case space is created to hold nIns bytes
+** beginning at iDel, but that space is uninitialized.
+**
+** Set pParse->oom if an OOM occurs.
+*/
+static void jsonBlobEdit(
+  JsonParse *pParse,     /* The JSONB to be modified is in pParse->aBlob */
+  u32 iDel,              /* First byte to be removed */
+  u32 nDel,              /* Number of bytes to remove */
+  const u8 *aIns,        /* Content to insert */
+  u32 nIns               /* Bytes of content to insert */
+){
+  i64 d = (i64)nIns - (i64)nDel;
+  if( d!=0 ){
+    if( pParse->nBlob + d > pParse->nBlobAlloc ){
+      jsonBlobExpand(pParse, pParse->nBlob+d);
+      if( pParse->oom ) return;
+    }
+    memmove(&pParse->aBlob[iDel+nIns],
+            &pParse->aBlob[iDel+nDel],
+            pParse->nBlob - (iDel+nDel));
+    pParse->nBlob += d;
+    pParse->delta += d;
+  }
+  if( nIns && aIns ) memcpy(&pParse->aBlob[iDel], aIns, nIns);
+}
+
+/*
+** Return the number of escaped newlines to be ignored.
+** An escaped newline is a one of the following byte sequences:
+**
+**    0x5c 0x0a
+**    0x5c 0x0d
+**    0x5c 0x0d 0x0a
+**    0x5c 0xe2 0x80 0xa8
+**    0x5c 0xe2 0x80 0xa9
+*/
+static u32 jsonBytesToBypass(const char *z, u32 n){
+  u32 i = 0;
+  while( i+1<n ){
+    if( z[i]!='\\' ) return i;
+    if( z[i+1]=='\n' ){
+      i += 2;
+      continue;
+    }
+    if( z[i+1]=='\r' ){
+      if( i+2<n && z[i+2]=='\n' ){
+        i += 3;
+      }else{
+        i += 2;
+      }
+      continue;
+    }
+    if( 0xe2==(u8)z[i+1]
+     && i+3<n
+     && 0x80==(u8)z[i+2]
+     && (0xa8==(u8)z[i+3] || 0xa9==(u8)z[i+3])
+    ){
+      i += 4;
+      continue;
+    }
+    break;
+  }
+  return i;
+}
+
+/*
+** Input z[0..n] defines JSON escape sequence including the leading '\\'.
+** Decode that escape sequence into a single character.  Write that
+** character into *piOut.  Return the number of bytes in the escape sequence.
+**
+** If there is a syntax error of some kind (for example too few characters
+** after the '\\' to complete the encoding) then *piOut is set to
+** JSON_INVALID_CHAR.
+*/
+static u32 jsonUnescapeOneChar(const char *z, u32 n, u32 *piOut){
+  assert( n>0 );
+  assert( z[0]=='\\' );
+  if( n<2 ){
+    *piOut = JSON_INVALID_CHAR;
+    return n;
+  }
+  switch( (u8)z[1] ){
+    case 'u': {
+      u32 v, vlo;
+      if( n<6 ){
+        *piOut = JSON_INVALID_CHAR;
+        return n;
+      }
+      v = jsonHexToInt4(&z[2]);
+      if( (v & 0xfc00)==0xd800
+       && n>=12
+       && z[6]=='\\'
+       && z[7]=='u'
+       && ((vlo = jsonHexToInt4(&z[8]))&0xfc00)==0xdc00
+      ){
+        *piOut = ((v&0x3ff)<<10) + (vlo&0x3ff) + 0x10000;
+        return 12;
+      }else{
+        *piOut = v;
+        return 6;
+      }
+    }
+    case 'b': {   *piOut = '\b';  return 2; }
+    case 'f': {   *piOut = '\f';  return 2; }
+    case 'n': {   *piOut = '\n';  return 2; }
+    case 'r': {   *piOut = '\r';  return 2; }
+    case 't': {   *piOut = '\t';  return 2; }
+    case 'v': {   *piOut = '\v';  return 2; }
+    case '0': {   *piOut = 0;     return 2; }
+    case '\'':
+    case '"':
+    case '/':
+    case '\\':{   *piOut = z[1];  return 2; }
+    case 'x': {
+      if( n<4 ){
+        *piOut = JSON_INVALID_CHAR;
+        return n;
+      }
+      *piOut = (jsonHexToInt(z[2])<<4) | jsonHexToInt(z[3]);
+      return 4;
+    }
+    case 0xe2:
+    case '\r':
+    case '\n': {
+      u32 nSkip = jsonBytesToBypass(z, n);
+      if( nSkip==0 ){
+        *piOut = JSON_INVALID_CHAR;
+        return n;
+      }else if( nSkip==n ){
+        *piOut = 0;
+        return n;
+      }else if( z[nSkip]=='\\' ){
+        return nSkip + jsonUnescapeOneChar(&z[nSkip], n-nSkip, piOut);
+      }else{
+        int sz = sqlite3Utf8ReadLimited((u8*)&z[nSkip], n-nSkip, piOut);
+        return nSkip + sz;
+      }
+    }
+    default: {
+      *piOut = JSON_INVALID_CHAR;
+      return 2;
+    }
+  }
+}
+
+
+/*
+** Compare two object labels.  Return 1 if they are equal and
+** 0 if they differ.
+**
+** In this version, we know that one or the other or both of the
+** two comparands contains an escape sequence.
+*/
+static SQLITE_NOINLINE int jsonLabelCompareEscaped(
+  const char *zLeft,          /* The left label */
+  u32 nLeft,                  /* Size of the left label in bytes */
+  int rawLeft,                /* True if zLeft contains no escapes */
+  const char *zRight,         /* The right label */
+  u32 nRight,                 /* Size of the right label in bytes */
+  int rawRight                /* True if zRight is escape-free */
+){
+  u32 cLeft, cRight;
+  assert( rawLeft==0 || rawRight==0 );
+  while( 1 /*exit-by-return*/ ){
+    if( nLeft==0 ){
+      cLeft = 0;
+    }else if( rawLeft || zLeft[0]!='\\' ){
+      cLeft = ((u8*)zLeft)[0];
+      if( cLeft>=0xc0 ){
+        int sz = sqlite3Utf8ReadLimited((u8*)zLeft, nLeft, &cLeft);
+        zLeft += sz;
+        nLeft -= sz;
+      }else{
+        zLeft++;
+        nLeft--;
+      }
+    }else{
+      u32 n = jsonUnescapeOneChar(zLeft, nLeft, &cLeft);
+      zLeft += n;
+      assert( n<=nLeft );
+      nLeft -= n;
+    }
+    if( nRight==0 ){
+      cRight = 0;
+    }else if( rawRight || zRight[0]!='\\' ){
+      cRight = ((u8*)zRight)[0];
+      if( cRight>=0xc0 ){
+        int sz = sqlite3Utf8ReadLimited((u8*)zRight, nRight, &cRight);
+        zRight += sz;
+        nRight -= sz;
+      }else{
+        zRight++;
+        nRight--;
+      }
+    }else{
+      u32 n = jsonUnescapeOneChar(zRight, nRight, &cRight);
+      zRight += n;
+      assert( n<=nRight );
+      nRight -= n;
+    }
+    if( cLeft!=cRight ) return 0;
+    if( cLeft==0 ) return 1;
+  }
+}
+
+/*
+** Compare two object labels.  Return 1 if they are equal and
+** 0 if they differ.  Return -1 if an OOM occurs.
+*/
+static int jsonLabelCompare(
+  const char *zLeft,          /* The left label */
+  u32 nLeft,                  /* Size of the left label in bytes */
+  int rawLeft,                /* True if zLeft contains no escapes */
+  const char *zRight,         /* The right label */
+  u32 nRight,                 /* Size of the right label in bytes */
+  int rawRight                /* True if zRight is escape-free */
+){
+  if( rawLeft && rawRight ){
+    /* Simpliest case:  Neither label contains escapes.  A simple
+    ** memcmp() is sufficient. */
+    if( nLeft!=nRight ) return 0;
+    return memcmp(zLeft, zRight, nLeft)==0;
+  }else{
+    return jsonLabelCompareEscaped(zLeft, nLeft, rawLeft,
+                                   zRight, nRight, rawRight);
+  }
+}
+
+/*
+** Error returns from jsonLookupStep()
+*/
+#define JSON_LOOKUP_ERROR      0xffffffff
+#define JSON_LOOKUP_NOTFOUND   0xfffffffe
+#define JSON_LOOKUP_PATHERROR  0xfffffffd
+#define JSON_LOOKUP_ISERROR(x) ((x)>=JSON_LOOKUP_PATHERROR)
+
+/* Forward declaration */
+static u32 jsonLookupStep(JsonParse*,u32,const char*,u32);
+
+
+/* This helper routine for jsonLookupStep() populates pIns with
+** binary data that is to be inserted into pParse.
+**
+** In the common case, pIns just points to pParse->aIns and pParse->nIns.
+** But if the zPath of the original edit operation includes path elements
+** that go deeper, additional substructure must be created.
+**
+** For example:
+**
+**     json_insert('{}', '$.a.b.c', 123);
+**
+** The search stops at '$.a'  But additional substructure must be
+** created for the ".b.c" part of the patch so that the final result
+** is:  {"a":{"b":{"c"::123}}}.  This routine populates pIns with
+** the binary equivalent of {"b":{"c":123}} so that it can be inserted.
+**
+** The caller is responsible for resetting pIns when it has finished
+** using the substructure.
+*/
+static u32 jsonCreateEditSubstructure(
+  JsonParse *pParse,  /* The original JSONB that is being edited */
+  JsonParse *pIns,    /* Populate this with the blob data to insert */
+  const char *zTail   /* Tail of the path that determins substructure */
+){
+  static const u8 emptyObject[] = { JSONB_ARRAY, JSONB_OBJECT };
+  int rc;
+  memset(pIns, 0, sizeof(*pIns));
+  pIns->db = pParse->db;
+  if( zTail[0]==0 ){
+    /* No substructure.  Just insert what is given in pParse. */
+    pIns->aBlob = pParse->aIns;
+    pIns->nBlob = pParse->nIns;
+    rc = 0;
+  }else{
+    /* Construct the binary substructure */
+    pIns->nBlob = 1;
+    pIns->aBlob = (u8*)&emptyObject[zTail[0]=='.'];
+    pIns->eEdit = pParse->eEdit;
+    pIns->nIns = pParse->nIns;
+    pIns->aIns = pParse->aIns;
+    rc = jsonLookupStep(pIns, 0, zTail, 0);
+    pParse->oom |= pIns->oom;
+  }
+  return rc;  /* Error code only */
+}
+
+/*
+** Search along zPath to find the Json element specified.  Return an
+** index into pParse->aBlob[] for the start of that element's value.
+**
+** If the value found by this routine is the value half of label/value pair
+** within an object, then set pPath->iLabel to the start of the corresponding
+** label, before returning.
+**
+** Return one of the JSON_LOOKUP error codes if problems are seen.
+**
+** This routine will also modify the blob.  If pParse->eEdit is one of
+** JEDIT_DEL, JEDIT_REPL, JEDIT_INS, or JEDIT_SET, then changes might be
+** made to the selected value.  If an edit is performed, then the return
+** value does not necessarily point to the select element.  If an edit
+** is performed, the return value is only useful for detecting error
+** conditions.
+*/
+static u32 jsonLookupStep(
+  JsonParse *pParse,      /* The JSON to search */
+  u32 iRoot,              /* Begin the search at this element of aBlob[] */
+  const char *zPath,      /* The path to search */
+  u32 iLabel              /* Label if iRoot is a value of in an object */
+){
+  u32 i, j, k, nKey, sz, n, iEnd, rc;
+  const char *zKey;
+  u8 x;
+
+  if( zPath[0]==0 ){
+    if( pParse->eEdit && jsonBlobMakeEditable(pParse, pParse->nIns) ){
+      n = jsonbPayloadSize(pParse, iRoot, &sz);
+      sz += n;
+      if( pParse->eEdit==JEDIT_DEL ){
+        if( iLabel>0 ){
+          sz += iRoot - iLabel;
+          iRoot = iLabel;
+        }
+        jsonBlobEdit(pParse, iRoot, sz, 0, 0);
+      }else if( pParse->eEdit==JEDIT_INS ){
+        /* Already exists, so json_insert() is a no-op */
+      }else{
+        /* json_set() or json_replace() */
+        jsonBlobEdit(pParse, iRoot, sz, pParse->aIns, pParse->nIns);
+      }
+    }
+    pParse->iLabel = iLabel;
+    return iRoot;
+  }
+  if( zPath[0]=='.' ){
+    int rawKey = 1;
+    x = pParse->aBlob[iRoot];
+    zPath++;
+    if( zPath[0]=='"' ){
+      zKey = zPath + 1;
+      for(i=1; zPath[i] && zPath[i]!='"'; i++){
+        if( zPath[i]=='\\' && zPath[i+1]!=0 ) i++;
+      }
+      nKey = i-1;
+      if( zPath[i] ){
+        i++;
+      }else{
+        return JSON_LOOKUP_PATHERROR;
+      }
+      testcase( nKey==0 );
+      rawKey = memchr(zKey, '\\', nKey)==0;
+    }else{
+      zKey = zPath;
+      for(i=0; zPath[i] && zPath[i]!='.' && zPath[i]!='['; i++){}
+      nKey = i;
+      if( nKey==0 ){
+        return JSON_LOOKUP_PATHERROR;
+      }
+    }
+    if( (x & 0x0f)!=JSONB_OBJECT ) return JSON_LOOKUP_NOTFOUND;
+    n = jsonbPayloadSize(pParse, iRoot, &sz);
+    j = iRoot + n;  /* j is the index of a label */
+    iEnd = j+sz;
+    while( j<iEnd ){
+      int rawLabel;
+      const char *zLabel;
+      x = pParse->aBlob[j] & 0x0f;
+      if( x<JSONB_TEXT || x>JSONB_TEXTRAW ) return JSON_LOOKUP_ERROR;
+      n = jsonbPayloadSize(pParse, j, &sz);
+      if( n==0 ) return JSON_LOOKUP_ERROR;
+      k = j+n;  /* k is the index of the label text */
+      if( k+sz>=iEnd ) return JSON_LOOKUP_ERROR;
+      zLabel = (const char*)&pParse->aBlob[k];
+      rawLabel = x==JSONB_TEXT || x==JSONB_TEXTRAW;
+      if( jsonLabelCompare(zKey, nKey, rawKey, zLabel, sz, rawLabel) ){
+        u32 v = k+sz;  /* v is the index of the value */
+        if( ((pParse->aBlob[v])&0x0f)>JSONB_OBJECT ) return JSON_LOOKUP_ERROR;
+        n = jsonbPayloadSize(pParse, v, &sz);
+        if( n==0 || v+n+sz>iEnd ) return JSON_LOOKUP_ERROR;
+        assert( j>0 );
+        rc = jsonLookupStep(pParse, v, &zPath[i], j);
+        if( pParse->delta ) jsonAfterEditSizeAdjust(pParse, iRoot);
+        return rc;
+      }
+      j = k+sz;
+      if( ((pParse->aBlob[j])&0x0f)>JSONB_OBJECT ) return JSON_LOOKUP_ERROR;
+      n = jsonbPayloadSize(pParse, j, &sz);
+      if( n==0 ) return JSON_LOOKUP_ERROR;
+      j += n+sz;
+    }
+    if( j>iEnd ) return JSON_LOOKUP_ERROR;
+    if( pParse->eEdit>=JEDIT_INS ){
+      u32 nIns;          /* Total bytes to insert (label+value) */
+      JsonParse v;       /* BLOB encoding of the value to be inserted */
+      JsonParse ix;      /* Header of the label to be inserted */
+      testcase( pParse->eEdit==JEDIT_INS );
+      testcase( pParse->eEdit==JEDIT_SET );
+      memset(&ix, 0, sizeof(ix));
+      ix.db = pParse->db;
+      jsonBlobAppendNode(&ix, rawKey?JSONB_TEXTRAW:JSONB_TEXT5, nKey, 0);
+      pParse->oom |= ix.oom;
+      rc = jsonCreateEditSubstructure(pParse, &v, &zPath[i]);
+      if( !JSON_LOOKUP_ISERROR(rc)
+       && jsonBlobMakeEditable(pParse, ix.nBlob+nKey+v.nBlob)
+      ){
+        assert( !pParse->oom );
+        nIns = ix.nBlob + nKey + v.nBlob;
+        jsonBlobEdit(pParse, j, 0, 0, nIns);
+        if( !pParse->oom ){
+          assert( pParse->aBlob!=0 ); /* Because pParse->oom!=0 */
+          assert( ix.aBlob!=0 );      /* Because pPasre->oom!=0 */
+          memcpy(&pParse->aBlob[j], ix.aBlob, ix.nBlob);
+          k = j + ix.nBlob;
+          memcpy(&pParse->aBlob[k], zKey, nKey);
+          k += nKey;
+          memcpy(&pParse->aBlob[k], v.aBlob, v.nBlob);
+          if( ALWAYS(pParse->delta) ) jsonAfterEditSizeAdjust(pParse, iRoot);
+        }
+      }
+      jsonParseReset(&v);
+      jsonParseReset(&ix);
+      return rc;
+    }
+  }else if( zPath[0]=='[' ){
+    x = pParse->aBlob[iRoot] & 0x0f;
+    if( x!=JSONB_ARRAY )  return JSON_LOOKUP_NOTFOUND;
+    n = jsonbPayloadSize(pParse, iRoot, &sz);
+    k = 0;
+    i = 1;
+    while( sqlite3Isdigit(zPath[i]) ){
+      k = k*10 + zPath[i] - '0';
+      i++;
+    }
+    if( i<2 || zPath[i]!=']' ){
+      if( zPath[1]=='#' ){
+        k = jsonbArrayCount(pParse, iRoot);
+        i = 2;
+        if( zPath[2]=='-' && sqlite3Isdigit(zPath[3]) ){
+          unsigned int nn = 0;
+          i = 3;
+          do{
+            nn = nn*10 + zPath[i] - '0';
+            i++;
+          }while( sqlite3Isdigit(zPath[i]) );
+          if( nn>k ) return JSON_LOOKUP_NOTFOUND;
+          k -= nn;
+        }
+        if( zPath[i]!=']' ){
+          return JSON_LOOKUP_PATHERROR;
+        }
+      }else{
+        return JSON_LOOKUP_PATHERROR;
+      }
+    }
+    j = iRoot+n;
+    iEnd = j+sz;
+    while( j<iEnd ){
+      if( k==0 ){
+        rc = jsonLookupStep(pParse, j, &zPath[i+1], 0);
+        if( pParse->delta ) jsonAfterEditSizeAdjust(pParse, iRoot);
+        return rc;
+      }
+      k--;
+      n = jsonbPayloadSize(pParse, j, &sz);
+      if( n==0 ) return JSON_LOOKUP_ERROR;
+      j += n+sz;
+    }
+    if( j>iEnd ) return JSON_LOOKUP_ERROR;
+    if( k>0 ) return JSON_LOOKUP_NOTFOUND;
+    if( pParse->eEdit>=JEDIT_INS ){
+      JsonParse v;
+      testcase( pParse->eEdit==JEDIT_INS );
+      testcase( pParse->eEdit==JEDIT_SET );
+      rc = jsonCreateEditSubstructure(pParse, &v, &zPath[i+1]);
+      if( !JSON_LOOKUP_ISERROR(rc)
+       && jsonBlobMakeEditable(pParse, v.nBlob)
+      ){
+        assert( !pParse->oom );
+        jsonBlobEdit(pParse, j, 0, v.aBlob, v.nBlob);
+      }
+      jsonParseReset(&v);
+      if( pParse->delta ) jsonAfterEditSizeAdjust(pParse, iRoot);
+      return rc;
+    }
+  }else{
+    return JSON_LOOKUP_PATHERROR;
+  }
+  return JSON_LOOKUP_NOTFOUND;
+}
+
+/*
+** Convert a JSON BLOB into text and make that text the return value
+** of an SQL function.
+*/
+static void jsonReturnTextJsonFromBlob(
+  sqlite3_context *ctx,
+  const u8 *aBlob,
+  u32 nBlob
+){
+  JsonParse x;
+  JsonString s;
+
+  if( NEVER(aBlob==0) ) return;
+  memset(&x, 0, sizeof(x));
+  x.aBlob = (u8*)aBlob;
+  x.nBlob = nBlob;
+  jsonStringInit(&s, ctx);
+  jsonTranslateBlobToText(&x, 0, &s);
+  jsonReturnString(&s, 0, 0);
+}
+
+
+/*
+** Return the value of the BLOB node at index i.
+**
+** If the value is a primitive, return it as an SQL value.
+** If the value is an array or object, return it as either
+** JSON text or the BLOB encoding, depending on the JSON_B flag
+** on the userdata.
+*/
+static void jsonReturnFromBlob(
+  JsonParse *pParse,          /* Complete JSON parse tree */
+  u32 i,                      /* Index of the node */
+  sqlite3_context *pCtx,      /* Return value for this function */
+  int textOnly                /* return text JSON.  Disregard user-data */
+){
+  u32 n, sz;
+  int rc;
+  sqlite3 *db = sqlite3_context_db_handle(pCtx);
+
+  n = jsonbPayloadSize(pParse, i, &sz);
+  if( n==0 ){
+    sqlite3_result_error(pCtx, "malformed JSON", -1);
+    return;
+  }
+  switch( pParse->aBlob[i] & 0x0f ){
+    case JSONB_NULL: {
+      if( sz ) goto returnfromblob_malformed;
+      sqlite3_result_null(pCtx);
+      break;
+    }
+    case JSONB_TRUE: {
+      if( sz ) goto returnfromblob_malformed;
+      sqlite3_result_int(pCtx, 1);
+      break;
+    }
+    case JSONB_FALSE: {
+      if( sz ) goto returnfromblob_malformed;
+      sqlite3_result_int(pCtx, 0);
+      break;
+    }
+    case JSONB_INT5:
+    case JSONB_INT: {
+      sqlite3_int64 iRes = 0;
+      char *z;
+      int bNeg = 0;
+      char x;
+      if( sz==0 ) goto returnfromblob_malformed;
+      x = (char)pParse->aBlob[i+n];
+      if( x=='-' ){
+        if( sz<2 ) goto returnfromblob_malformed;
+        n++;
+        sz--;
+        bNeg = 1;
+      }
+      z = sqlite3DbStrNDup(db, (const char*)&pParse->aBlob[i+n], (int)sz);
+      if( z==0 ) goto returnfromblob_oom;
+      rc = sqlite3DecOrHexToI64(z, &iRes);
+      sqlite3DbFree(db, z);
+      if( rc==0 ){
+        sqlite3_result_int64(pCtx, bNeg ? -iRes : iRes);
+      }else if( rc==3 && bNeg ){
+        sqlite3_result_int64(pCtx, SMALLEST_INT64);
+      }else if( rc==1 ){
+        goto returnfromblob_malformed;
+      }else{
+        if( bNeg ){ n--; sz++; }
+        goto to_double;
+      }
+      break;
+    }
+    case JSONB_FLOAT5:
+    case JSONB_FLOAT: {
+      double r;
+      char *z;
+      if( sz==0 ) goto returnfromblob_malformed;
+    to_double:
+      z = sqlite3DbStrNDup(db, (const char*)&pParse->aBlob[i+n], (int)sz);
+      if( z==0 ) goto returnfromblob_oom;
+      rc = sqlite3AtoF(z, &r, sqlite3Strlen30(z), SQLITE_UTF8);
+      sqlite3DbFree(db, z);
+      if( rc<=0 ) goto returnfromblob_malformed;
+      sqlite3_result_double(pCtx, r);
+      break;
+    }
+    case JSONB_TEXTRAW:
+    case JSONB_TEXT: {
+      sqlite3_result_text(pCtx, (char*)&pParse->aBlob[i+n], sz,
+                          SQLITE_TRANSIENT);
+      break;
+    }
+    case JSONB_TEXT5:
+    case JSONB_TEXTJ: {
+      /* Translate JSON formatted string into raw text */
+      u32 iIn, iOut;
+      const char *z;
+      char *zOut;
+      u32 nOut = sz;
+      z = (const char*)&pParse->aBlob[i+n];
+      zOut = sqlite3DbMallocRaw(db, nOut+1);
+      if( zOut==0 ) goto returnfromblob_oom;
+      for(iIn=iOut=0; iIn<sz; iIn++){
+        char c = z[iIn];
+        if( c=='\\' ){
+          u32 v;
+          u32 szEscape = jsonUnescapeOneChar(&z[iIn], sz-iIn, &v);
+          if( v<=0x7f ){
+            zOut[iOut++] = (char)v;
+          }else if( v<=0x7ff ){
+            assert( szEscape>=2 );
+            zOut[iOut++] = (char)(0xc0 | (v>>6));
+            zOut[iOut++] = 0x80 | (v&0x3f);
+          }else if( v<0x10000 ){
+            assert( szEscape>=3 );
+            zOut[iOut++] = 0xe0 | (v>>12);
+            zOut[iOut++] = 0x80 | ((v>>6)&0x3f);
+            zOut[iOut++] = 0x80 | (v&0x3f);
+          }else if( v==JSON_INVALID_CHAR ){
+            /* Silently ignore illegal unicode */
+          }else{
+            assert( szEscape>=4 );
+            zOut[iOut++] = 0xf0 | (v>>18);
+            zOut[iOut++] = 0x80 | ((v>>12)&0x3f);
+            zOut[iOut++] = 0x80 | ((v>>6)&0x3f);
+            zOut[iOut++] = 0x80 | (v&0x3f);
+          }
+          iIn += szEscape - 1;
+        }else{
+          zOut[iOut++] = c;
+        }
+      } /* end for() */
+      assert( iOut<=nOut );
+      zOut[iOut] = 0;
+      sqlite3_result_text(pCtx, zOut, iOut, SQLITE_DYNAMIC);
+      break;
+    }
+    case JSONB_ARRAY:
+    case JSONB_OBJECT: {
+      int flags = textOnly ? 0 : SQLITE_PTR_TO_INT(sqlite3_user_data(pCtx));
+      if( flags & JSON_BLOB ){
+        sqlite3_result_blob(pCtx, &pParse->aBlob[i], sz+n, SQLITE_TRANSIENT);
+      }else{
+        jsonReturnTextJsonFromBlob(pCtx, &pParse->aBlob[i], sz+n);
+      }
+      break;
+    }
+    default: {
+      goto returnfromblob_malformed;
+    }
+  }
+  return;
+
+returnfromblob_oom:
+  sqlite3_result_error_nomem(pCtx);
+  return;
+
+returnfromblob_malformed:
+  sqlite3_result_error(pCtx, "malformed JSON", -1);
+  return;
+}
+
+/*
+** pArg is a function argument that might be an SQL value or a JSON
+** value.  Figure out what it is and encode it as a JSONB blob.
+** Return the results in pParse.
+**
+** pParse is uninitialized upon entry.  This routine will handle the
+** initialization of pParse.  The result will be contained in
+** pParse->aBlob and pParse->nBlob.  pParse->aBlob might be dynamically
+** allocated (if pParse->nBlobAlloc is greater than zero) in which case
+** the caller is responsible for freeing the space allocated to pParse->aBlob
+** when it has finished with it.  Or pParse->aBlob might be a static string
+** or a value obtained from sqlite3_value_blob(pArg).
+**
+** If the argument is a BLOB that is clearly not a JSONB, then this
+** function might set an error message in ctx and return non-zero.
+** It might also set an error message and return non-zero on an OOM error.
+*/
+static int jsonFunctionArgToBlob(
+  sqlite3_context *ctx,
+  sqlite3_value *pArg,
+  JsonParse *pParse
+){
+  int eType = sqlite3_value_type(pArg);
+  static u8 aNull[] = { 0x00 };
+  memset(pParse, 0, sizeof(pParse[0]));
+  pParse->db = sqlite3_context_db_handle(ctx);
+  switch( eType ){
+    default: {
+      pParse->aBlob = aNull;
+      pParse->nBlob = 1;
+      return 0;
+    }
+    case SQLITE_BLOB: {
+      if( jsonFuncArgMightBeBinary(pArg) ){
+        pParse->aBlob = (u8*)sqlite3_value_blob(pArg);
+        pParse->nBlob = sqlite3_value_bytes(pArg);
+      }else{
+        sqlite3_result_error(ctx, "JSON cannot hold BLOB values", -1);
+        return 1;
+      }
+      break;
+    }
+    case SQLITE_TEXT: {
+      const char *zJson = (const char*)sqlite3_value_text(pArg);
+      int nJson = sqlite3_value_bytes(pArg);
+      if( zJson==0 ) return 1;
+      if( sqlite3_value_subtype(pArg)==JSON_SUBTYPE ){
+        pParse->zJson = (char*)zJson;
+        pParse->nJson = nJson;
+        if( jsonConvertTextToBlob(pParse, ctx) ){
+          sqlite3_result_error(ctx, "malformed JSON", -1);
+          sqlite3DbFree(pParse->db, pParse->aBlob);
+          memset(pParse, 0, sizeof(pParse[0]));
+          return 1;
+        }
+      }else{
+        jsonBlobAppendNode(pParse, JSONB_TEXTRAW, nJson, zJson);
+      }
+      break;
+    }
+    case SQLITE_FLOAT: {
+      double r = sqlite3_value_double(pArg);
+      if( NEVER(sqlite3IsNaN(r)) ){
+        jsonBlobAppendNode(pParse, JSONB_NULL, 0, 0);
+      }else{
+        int n = sqlite3_value_bytes(pArg);
+        const char *z = (const char*)sqlite3_value_text(pArg);
+        if( z==0 ) return 1;
+        if( z[0]=='I' ){
+          jsonBlobAppendNode(pParse, JSONB_FLOAT, 5, "9e999");
+        }else if( z[0]=='-' && z[1]=='I' ){
+          jsonBlobAppendNode(pParse, JSONB_FLOAT, 6, "-9e999");
+        }else{
+          jsonBlobAppendNode(pParse, JSONB_FLOAT, n, z);
+        }
+      }
+      break;
+    }
+    case SQLITE_INTEGER: {
+      int n = sqlite3_value_bytes(pArg);
+      const char *z = (const char*)sqlite3_value_text(pArg);
+      if( z==0 ) return 1;
+      jsonBlobAppendNode(pParse, JSONB_INT, n, z);
+      break;
+    }
+  }
+  if( pParse->oom ){
+    sqlite3_result_error_nomem(ctx);
+    return 1;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Generate a bad path error.
+**
+** If ctx is not NULL then push the error message into ctx and return NULL.
+** If ctx is NULL, then return the text of the error message.
+*/
+static char *jsonBadPathError(
+  sqlite3_context *ctx,     /* The function call containing the error */
+  const char *zPath         /* The path with the problem */
+){
+  char *zMsg = sqlite3_mprintf("bad JSON path: %Q", zPath);
+  if( ctx==0 ) return zMsg;
+  if( zMsg ){
+    sqlite3_result_error(ctx, zMsg, -1);
+    sqlite3_free(zMsg);
+  }else{
+    sqlite3_result_error_nomem(ctx);
+  }
+  return 0;
+}
+
+/* argv[0] is a BLOB that seems likely to be a JSONB.  Subsequent
+** arguments come in parse where each pair contains a JSON path and
+** content to insert or set at that patch.  Do the updates
+** and return the result.
+**
+** The specific operation is determined by eEdit, which can be one
+** of JEDIT_INS, JEDIT_REPL, or JEDIT_SET.
+*/
+static void jsonInsertIntoBlob(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv,
+  int eEdit                /* JEDIT_INS, JEDIT_REPL, or JEDIT_SET */
+){
+  int i;
+  u32 rc = 0;
+  const char *zPath = 0;
+  int flgs;
+  JsonParse *p;
+  JsonParse ax;
+
+  assert( (argc&1)==1 );
+  flgs = argc==1 ? 0 : JSON_EDITABLE;
+  p = jsonParseFuncArg(ctx, argv[0], flgs);
+  if( p==0 ) return;
+  for(i=1; i<argc-1; i+=2){
+    if( sqlite3_value_type(argv[i])==SQLITE_NULL ) continue;
+    zPath = (const char*)sqlite3_value_text(argv[i]);
+    if( zPath==0 ){
+      sqlite3_result_error_nomem(ctx);
+      jsonParseFree(p);
+      return;
+    }
+    if( zPath[0]!='$' ) goto jsonInsertIntoBlob_patherror;
+    if( jsonFunctionArgToBlob(ctx, argv[i+1], &ax) ){
+      jsonParseReset(&ax);
+      jsonParseFree(p);
+      return;
+    }
+    if( zPath[1]==0 ){
+      if( eEdit==JEDIT_REPL || eEdit==JEDIT_SET ){
+        jsonBlobEdit(p, 0, p->nBlob, ax.aBlob, ax.nBlob);
+      }
+      rc = 0;
+   }else{
+      p->eEdit = eEdit;
+      p->nIns = ax.nBlob;
+      p->aIns = ax.aBlob;
+      p->delta = 0;
+      rc = jsonLookupStep(p, 0, zPath+1, 0);
+    }
+    jsonParseReset(&ax);
+    if( rc==JSON_LOOKUP_NOTFOUND ) continue;
+    if( JSON_LOOKUP_ISERROR(rc) ) goto jsonInsertIntoBlob_patherror;
+  }
+  jsonReturnParse(ctx, p);
+  jsonParseFree(p);
+  return;
+
+jsonInsertIntoBlob_patherror:
+  jsonParseFree(p);
+  if( rc==JSON_LOOKUP_ERROR ){
+    sqlite3_result_error(ctx, "malformed JSON", -1);
+  }else{
+    jsonBadPathError(ctx, zPath);
+  }
+  return;
+}
+
+/*
+** If pArg is a blob that seems like a JSONB blob, then initialize
+** p to point to that JSONB and return TRUE.  If pArg does not seem like
+** a JSONB blob, then return FALSE;
+**
+** This routine is only called if it is already known that pArg is a
+** blob.  The only open question is whether or not the blob appears
+** to be a JSONB blob.
+*/
+static int jsonArgIsJsonb(sqlite3_value *pArg, JsonParse *p){
+  u32 n, sz = 0;
+  p->aBlob = (u8*)sqlite3_value_blob(pArg);
+  p->nBlob = (u32)sqlite3_value_bytes(pArg);
+  if( p->nBlob==0 ){
+    p->aBlob = 0;
+    return 0;
+  }
+  if( NEVER(p->aBlob==0) ){
+    return 0;
+  }
+  if( (p->aBlob[0] & 0x0f)<=JSONB_OBJECT
+   && (n = jsonbPayloadSize(p, 0, &sz))>0
+   && sz+n==p->nBlob
+   && ((p->aBlob[0] & 0x0f)>JSONB_FALSE || sz==0)
+  ){
+    return 1;
+  }
+  p->aBlob = 0;
+  p->nBlob = 0;
+  return 0;
+}
+
+/*
+** Generate a JsonParse object, containing valid JSONB in aBlob and nBlob,
+** from the SQL function argument pArg.  Return a pointer to the new
+** JsonParse object.
+**
+** Ownership of the new JsonParse object is passed to the caller.  The
+** caller should invoke jsonParseFree() on the return value when it
+** has finished using it.
+**
+** If any errors are detected, an appropriate error messages is set
+** using sqlite3_result_error() or the equivalent and this routine
+** returns NULL.  This routine also returns NULL if the pArg argument
+** is an SQL NULL value, but no error message is set in that case.  This
+** is so that SQL functions that are given NULL arguments will return
+** a NULL value.
+*/
+static JsonParse *jsonParseFuncArg(
+  sqlite3_context *ctx,
+  sqlite3_value *pArg,
+  u32 flgs
+){
+  int eType;                   /* Datatype of pArg */
+  JsonParse *p = 0;            /* Value to be returned */
+  JsonParse *pFromCache = 0;   /* Value taken from cache */
+  sqlite3 *db;                 /* The database connection */
+
+  assert( ctx!=0 );
+  eType = sqlite3_value_type(pArg);
+  if( eType==SQLITE_NULL ){
+    return 0;
+  }
+  pFromCache = jsonCacheSearch(ctx, pArg);
+  if( pFromCache ){
+    pFromCache->nJPRef++;
+    if( (flgs & JSON_EDITABLE)==0 ){
+      return pFromCache;
+    }
+  }
+  db = sqlite3_context_db_handle(ctx);
+rebuild_from_cache:
+  p = sqlite3DbMallocZero(db, sizeof(*p));
+  if( p==0 ) goto json_pfa_oom;
+  memset(p, 0, sizeof(*p));
+  p->db = db;
+  p->nJPRef = 1;
+  if( pFromCache!=0 ){
+    u32 nBlob = pFromCache->nBlob;
+    p->aBlob = sqlite3DbMallocRaw(db, nBlob);
+    if( p->aBlob==0 ) goto json_pfa_oom;
+    memcpy(p->aBlob, pFromCache->aBlob, nBlob);
+    p->nBlobAlloc = p->nBlob = nBlob;
+    p->hasNonstd = pFromCache->hasNonstd;
+    jsonParseFree(pFromCache);
+    return p;
+  }
+  if( eType==SQLITE_BLOB ){
+    if( jsonArgIsJsonb(pArg,p) ){
+      if( (flgs & JSON_EDITABLE)!=0 && jsonBlobMakeEditable(p, 0)==0 ){
+        goto json_pfa_oom;
+      }
+      return p;
+    }
+    /* If the blob is not valid JSONB, fall through into trying to cast
+    ** the blob into text which is then interpreted as JSON.  (tag-20240123-a)
+    **
+    ** This goes against all historical documentation about how the SQLite
+    ** JSON functions were suppose to work.  From the beginning, blob was
+    ** reserved for expansion and a blob value should have raised an error.
+    ** But it did not, due to a bug.  And many applications came to depend
+    ** upon this buggy behavior, espeically when using the CLI and reading
+    ** JSON text using readfile(), which returns a blob.  For this reason
+    ** we will continue to support the bug moving forward.
+    ** See for example https://sqlite.org/forum/forumpost/012136abd5292b8d
+    */
+  }
+  p->zJson = (char*)sqlite3_value_text(pArg);
+  p->nJson = sqlite3_value_bytes(pArg);
+  if( db->mallocFailed ) goto json_pfa_oom;
+  if( p->nJson==0 ) goto json_pfa_malformed;
+  assert( p->zJson!=0 );
+  if( jsonConvertTextToBlob(p, (flgs & JSON_KEEPERROR) ? 0 : ctx) ){
+    if( flgs & JSON_KEEPERROR ){
+      p->nErr = 1;
+      return p;
+    }else{
+      jsonParseFree(p);
+      return 0;
+    }
+  }else{
+    int isRCStr = sqlite3ValueIsOfClass(pArg, sqlite3RCStrUnref);
+    int rc;
+    if( !isRCStr ){
+      char *zNew = sqlite3RCStrNew( p->nJson );
+      if( zNew==0 ) goto json_pfa_oom;
+      memcpy(zNew, p->zJson, p->nJson);
+      p->zJson = zNew;
+      p->zJson[p->nJson] = 0;
+    }else{
+      sqlite3RCStrRef(p->zJson);
+    }
+    p->bJsonIsRCStr = 1;
+    rc = jsonCacheInsert(ctx, p);
+    if( rc==SQLITE_NOMEM ) goto json_pfa_oom;
+    if( flgs & JSON_EDITABLE ){
+      pFromCache = p;
+      p = 0;
+      goto rebuild_from_cache;
+    }
+  }
+  return p;
+
+json_pfa_malformed:
+  if( flgs & JSON_KEEPERROR ){
+    p->nErr = 1;
+    return p;
+  }else{
+    jsonParseFree(p);
+    sqlite3_result_error(ctx, "malformed JSON", -1);
+    return 0;
+  }
+
+json_pfa_oom:
+  jsonParseFree(pFromCache);
+  jsonParseFree(p);
+  sqlite3_result_error_nomem(ctx);
+  return 0;
+}
+
+/*
+** Make the return value of a JSON function either the raw JSONB blob
+** or make it JSON text, depending on whether the JSON_BLOB flag is
+** set on the function.
+*/
+static void jsonReturnParse(
+  sqlite3_context *ctx,
+  JsonParse *p
+){
+  int flgs;
+  if( p->oom ){
+    sqlite3_result_error_nomem(ctx);
+    return;
+  }
+  flgs = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+  if( flgs & JSON_BLOB ){
+    if( p->nBlobAlloc>0 && !p->bReadOnly ){
+      sqlite3_result_blob(ctx, p->aBlob, p->nBlob, SQLITE_DYNAMIC);
+      p->nBlobAlloc = 0;
+    }else{
+      sqlite3_result_blob(ctx, p->aBlob, p->nBlob, SQLITE_TRANSIENT);
+    }
+  }else{
+    JsonString s;
+    jsonStringInit(&s, ctx);
+    p->delta = 0;
+    jsonTranslateBlobToText(p, 0, &s);
+    jsonReturnString(&s, p, ctx);
+    sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+  }
+}
+
+/****************************************************************************
+** SQL functions used for testing and debugging
+****************************************************************************/
+
+#if SQLITE_DEBUG
+/*
+** Decode JSONB bytes in aBlob[] starting at iStart through but not
+** including iEnd.  Indent the
+** content by nIndent spaces.
+*/
+static void jsonDebugPrintBlob(
+  JsonParse *pParse, /* JSON content */
+  u32 iStart,        /* Start rendering here */
+  u32 iEnd,          /* Do not render this byte or any byte after this one */
+  int nIndent,       /* Indent by this many spaces */
+  sqlite3_str *pOut  /* Generate output into this sqlite3_str object */
+){
+  while( iStart<iEnd ){
+    u32 i, n, nn, sz = 0;
+    int showContent = 1;
+    u8 x = pParse->aBlob[iStart] & 0x0f;
+    u32 savedNBlob = pParse->nBlob;
+    sqlite3_str_appendf(pOut, "%5d:%*s", iStart, nIndent, "");
+    if( pParse->nBlobAlloc>pParse->nBlob ){
+      pParse->nBlob = pParse->nBlobAlloc;
+    }
+    nn = n = jsonbPayloadSize(pParse, iStart, &sz);
+    if( nn==0 ) nn = 1;
+    if( sz>0 && x<JSONB_ARRAY ){
+      nn += sz;
+    }
+    for(i=0; i<nn; i++){
+      sqlite3_str_appendf(pOut, " %02x", pParse->aBlob[iStart+i]);
+    }
+    if( n==0 ){
+      sqlite3_str_appendf(pOut, "   ERROR invalid node size\n");
+      iStart = n==0 ? iStart+1 : iEnd;
+      continue;
+    }
+    pParse->nBlob = savedNBlob;
+    if( iStart+n+sz>iEnd ){
+      iEnd = iStart+n+sz;
+      if( iEnd>pParse->nBlob ){
+        if( pParse->nBlobAlloc>0 && iEnd>pParse->nBlobAlloc ){
+          iEnd = pParse->nBlobAlloc;
+        }else{
+          iEnd = pParse->nBlob;
+        }
+      }
+    }
+    sqlite3_str_appendall(pOut,"  <-- ");
+    switch( x ){
+      case JSONB_NULL:     sqlite3_str_appendall(pOut,"null"); break;
+      case JSONB_TRUE:     sqlite3_str_appendall(pOut,"true"); break;
+      case JSONB_FALSE:    sqlite3_str_appendall(pOut,"false"); break;
+      case JSONB_INT:      sqlite3_str_appendall(pOut,"int"); break;
+      case JSONB_INT5:     sqlite3_str_appendall(pOut,"int5"); break;
+      case JSONB_FLOAT:    sqlite3_str_appendall(pOut,"float"); break;
+      case JSONB_FLOAT5:   sqlite3_str_appendall(pOut,"float5"); break;
+      case JSONB_TEXT:     sqlite3_str_appendall(pOut,"text"); break;
+      case JSONB_TEXTJ:    sqlite3_str_appendall(pOut,"textj"); break;
+      case JSONB_TEXT5:    sqlite3_str_appendall(pOut,"text5"); break;
+      case JSONB_TEXTRAW:  sqlite3_str_appendall(pOut,"textraw"); break;
+      case JSONB_ARRAY: {
+        sqlite3_str_appendf(pOut,"array, %u bytes\n", sz);
+        jsonDebugPrintBlob(pParse, iStart+n, iStart+n+sz, nIndent+2, pOut);
+        showContent = 0;
+        break;
+      }
+      case JSONB_OBJECT: {
+        sqlite3_str_appendf(pOut, "object, %u bytes\n", sz);
+        jsonDebugPrintBlob(pParse, iStart+n, iStart+n+sz, nIndent+2, pOut);
+        showContent = 0;
+        break;
+      }
+      default: {
+        sqlite3_str_appendall(pOut, "ERROR: unknown node type\n");
+        showContent = 0;
+        break;
+      }
+    }
+    if( showContent ){
+      if( sz==0 && x<=JSONB_FALSE ){
+        sqlite3_str_append(pOut, "\n", 1);
+      }else{
+        u32 j;
+        sqlite3_str_appendall(pOut, ": \"");
+        for(j=iStart+n; j<iStart+n+sz; j++){
+          u8 c = pParse->aBlob[j];
+          if( c<0x20 || c>=0x7f ) c = '.';
+          sqlite3_str_append(pOut, (char*)&c, 1);
+        }
+        sqlite3_str_append(pOut, "\"\n", 2);
+      }
+    }
+    iStart += n + sz;
+  }
+}
+static void jsonShowParse(JsonParse *pParse){
+  sqlite3_str out;
+  char zBuf[1000];
+  if( pParse==0 ){
+    printf("NULL pointer\n");
+    return;
+  }else{
+    printf("nBlobAlloc = %u\n", pParse->nBlobAlloc);
+    printf("nBlob = %u\n", pParse->nBlob);
+    printf("delta = %d\n", pParse->delta);
+    if( pParse->nBlob==0 ) return;
+    printf("content (bytes 0..%u):\n", pParse->nBlob-1);
+  }
+  sqlite3StrAccumInit(&out, 0, zBuf, sizeof(zBuf), 1000000);
+  jsonDebugPrintBlob(pParse, 0, pParse->nBlob, 0, &out);
+  printf("%s", sqlite3_str_value(&out));
+  sqlite3_str_reset(&out);
+}
+#endif /* SQLITE_DEBUG */
+
+#ifdef SQLITE_DEBUG
+/*
+** SQL function:   json_parse(JSON)
+**
+** Parse JSON using jsonParseFuncArg().  Return text that is a
+** human-readable dump of the binary JSONB for the input parameter.
+*/
+static void jsonParseFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;        /* The parse */
+  sqlite3_str out;
+
+  assert( argc>=1 );
+  sqlite3StrAccumInit(&out, 0, 0, 0, 1000000);
+  p = jsonParseFuncArg(ctx, argv[0], 0);
+  if( p==0 ) return;
+  if( argc==1 ){
+    jsonDebugPrintBlob(p, 0, p->nBlob, 0, &out);
+    sqlite3_result_text64(ctx,out.zText,out.nChar,SQLITE_TRANSIENT,SQLITE_UTF8);
+  }else{
+    jsonShowParse(p);
+  }
+  jsonParseFree(p);
+  sqlite3_str_reset(&out);
+}
+#endif /* SQLITE_DEBUG */
+
+/****************************************************************************
+** Scalar SQL function implementations
+****************************************************************************/
+
+/*
+** Implementation of the json_quote(VALUE) function.  Return a JSON value
+** corresponding to the SQL value input.  Mostly this means putting
+** double-quotes around strings and returning the unquoted string "null"
+** when given a NULL input.
+*/
+static void jsonQuoteFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonString jx;
+  UNUSED_PARAMETER(argc);
+
+  jsonStringInit(&jx, ctx);
+  jsonAppendSqlValue(&jx, argv[0]);
+  jsonReturnString(&jx, 0, 0);
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+
+/*
+** Implementation of the json_array(VALUE,...) function.  Return a JSON
+** array that contains all values given in arguments.  Or if any argument
+** is a BLOB, throw an error.
+*/
+static void jsonArrayFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+  JsonString jx;
+
+  jsonStringInit(&jx, ctx);
+  jsonAppendChar(&jx, '[');
+  for(i=0; i<argc; i++){
+    jsonAppendSeparator(&jx);
+    jsonAppendSqlValue(&jx, argv[i]);
+  }
+  jsonAppendChar(&jx, ']');
+  jsonReturnString(&jx, 0, 0);
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+
+/*
+** json_array_length(JSON)
+** json_array_length(JSON, PATH)
+**
+** Return the number of elements in the top-level JSON array.
+** Return 0 if the input is not a well-formed JSON array.
+*/
+static void jsonArrayLengthFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;          /* The parse */
+  sqlite3_int64 cnt = 0;
+  u32 i;
+  u8 eErr = 0;
+
+  p = jsonParseFuncArg(ctx, argv[0], 0);
+  if( p==0 ) return;
+  if( argc==2 ){
+    const char *zPath = (const char*)sqlite3_value_text(argv[1]);
+    if( zPath==0 ){
+      jsonParseFree(p);
+      return;
+    }
+    i = jsonLookupStep(p, 0, zPath[0]=='$' ? zPath+1 : "@", 0);
+    if( JSON_LOOKUP_ISERROR(i) ){
+      if( i==JSON_LOOKUP_NOTFOUND ){
+        /* no-op */
+      }else if( i==JSON_LOOKUP_PATHERROR ){
+        jsonBadPathError(ctx, zPath);
+      }else{
+        sqlite3_result_error(ctx, "malformed JSON", -1);
+      }
+      eErr = 1;
+      i = 0;
+    }
+  }else{
+    i = 0;
+  }
+  if( (p->aBlob[i] & 0x0f)==JSONB_ARRAY ){
+    cnt = jsonbArrayCount(p, i);
+  }
+  if( !eErr ) sqlite3_result_int64(ctx, cnt);
+  jsonParseFree(p);
+}
+
+/* True if the string is all alphanumerics and underscores */
+static int jsonAllAlphanum(const char *z, int n){
+  int i;
+  for(i=0; i<n && (sqlite3Isalnum(z[i]) || z[i]=='_'); i++){}
+  return i==n;
+}
+
+/*
+** json_extract(JSON, PATH, ...)
+** "->"(JSON,PATH)
+** "->>"(JSON,PATH)
+**
+** Return the element described by PATH.  Return NULL if that PATH element
+** is not found.
+**
+** If JSON_JSON is set or if more that one PATH argument is supplied then
+** always return a JSON representation of the result.  If JSON_SQL is set,
+** then always return an SQL representation of the result.  If neither flag
+** is present and argc==2, then return JSON for objects and arrays and SQL
+** for all other values.
+**
+** When multiple PATH arguments are supplied, the result is a JSON array
+** containing the result of each PATH.
+**
+** Abbreviated JSON path expressions are allows if JSON_ABPATH, for
+** compatibility with PG.
+*/
+static void jsonExtractFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p = 0;      /* The parse */
+  int flags;             /* Flags associated with the function */
+  int i;                 /* Loop counter */
+  JsonString jx;         /* String for array result */
+
+  if( argc<2 ) return;
+  p = jsonParseFuncArg(ctx, argv[0], 0);
+  if( p==0 ) return;
+  flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+  jsonStringInit(&jx, ctx);
+  if( argc>2 ){
+    jsonAppendChar(&jx, '[');
+  }
+  for(i=1; i<argc; i++){
+    /* With a single PATH argument */
+    const char *zPath = (const char*)sqlite3_value_text(argv[i]);
+    int nPath;
+    u32 j;
+    if( zPath==0 ) goto json_extract_error;
+    nPath = sqlite3Strlen30(zPath);
+    if( zPath[0]=='$' ){
+      j = jsonLookupStep(p, 0, zPath+1, 0);
+    }else if( (flags & JSON_ABPATH) ){
+      /* The -> and ->> operators accept abbreviated PATH arguments.  This
+      ** is mostly for compatibility with PostgreSQL, but also for
+      ** convenience.
+      **
+      **     NUMBER   ==>  $[NUMBER]     // PG compatible
+      **     LABEL    ==>  $.LABEL       // PG compatible
+      **     [NUMBER] ==>  $[NUMBER]     // Not PG.  Purely for convenience
+      **
+      ** Updated 2024-05-27:  If the NUMBER is negative, then PG counts from
+      ** the right of the array.  Hence for negative NUMBER:
+      **
+      **     NUMBER   ==>  $[#NUMBER]    // PG compatible
+      */
+      jsonStringInit(&jx, ctx);
+      if( sqlite3_value_type(argv[i])==SQLITE_INTEGER ){
+        jsonAppendRawNZ(&jx, "[", 1);
+        if( zPath[0]=='-' ) jsonAppendRawNZ(&jx,"#",1);
+        jsonAppendRaw(&jx, zPath, nPath);
+        jsonAppendRawNZ(&jx, "]", 2);
+      }else if( jsonAllAlphanum(zPath, nPath) ){
+        jsonAppendRawNZ(&jx, ".", 1);
+        jsonAppendRaw(&jx, zPath, nPath);
+      }else if( zPath[0]=='[' && nPath>=3 && zPath[nPath-1]==']' ){
+        jsonAppendRaw(&jx, zPath, nPath);
+      }else{
+        jsonAppendRawNZ(&jx, ".\"", 2);
+        jsonAppendRaw(&jx, zPath, nPath);
+        jsonAppendRawNZ(&jx, "\"", 1);
+      }
+      jsonStringTerminate(&jx);
+      j = jsonLookupStep(p, 0, jx.zBuf, 0);
+      jsonStringReset(&jx);
+    }else{
+      jsonBadPathError(ctx, zPath);
+      goto json_extract_error;
+    }
+    if( j<p->nBlob ){
+      if( argc==2 ){
+        if( flags & JSON_JSON ){
+          jsonStringInit(&jx, ctx);
+          jsonTranslateBlobToText(p, j, &jx);
+          jsonReturnString(&jx, 0, 0);
+          jsonStringReset(&jx);
+          assert( (flags & JSON_BLOB)==0 );
+          sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+        }else{
+          jsonReturnFromBlob(p, j, ctx, 0);
+          if( (flags & (JSON_SQL|JSON_BLOB))==0
+           && (p->aBlob[j]&0x0f)>=JSONB_ARRAY
+          ){
+            sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+          }
+        }
+      }else{
+        jsonAppendSeparator(&jx);
+        jsonTranslateBlobToText(p, j, &jx);
+      }
+    }else if( j==JSON_LOOKUP_NOTFOUND ){
+      if( argc==2 ){
+        goto json_extract_error;  /* Return NULL if not found */
+      }else{
+        jsonAppendSeparator(&jx);
+        jsonAppendRawNZ(&jx, "null", 4);
+      }
+    }else if( j==JSON_LOOKUP_ERROR ){
+      sqlite3_result_error(ctx, "malformed JSON", -1);
+      goto json_extract_error;
+    }else{
+      jsonBadPathError(ctx, zPath);
+      goto json_extract_error;
+    }
+  }
+  if( argc>2 ){
+    jsonAppendChar(&jx, ']');
+    jsonReturnString(&jx, 0, 0);
+    if( (flags & JSON_BLOB)==0 ){
+      sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+    }
+  }
+json_extract_error:
+  jsonStringReset(&jx);
+  jsonParseFree(p);
+  return;
+}
+
+/*
+** Return codes for jsonMergePatch()
+*/
+#define JSON_MERGE_OK          0     /* Success */
+#define JSON_MERGE_BADTARGET   1     /* Malformed TARGET blob */
+#define JSON_MERGE_BADPATCH    2     /* Malformed PATCH blob */
+#define JSON_MERGE_OOM         3     /* Out-of-memory condition */
+
+/*
+** RFC-7396 MergePatch for two JSONB blobs.
+**
+** pTarget is the target. pPatch is the patch.  The target is updated
+** in place.  The patch is read-only.
+**
+** The original RFC-7396 algorithm is this:
+**
+**   define MergePatch(Target, Patch):
+**     if Patch is an Object:
+**       if Target is not an Object:
+**         Target = {} # Ignore the contents and set it to an empty Object
+**     for each Name/Value pair in Patch:
+**         if Value is null:
+**           if Name exists in Target:
+**             remove the Name/Value pair from Target
+**         else:
+**           Target[Name] = MergePatch(Target[Name], Value)
+**       return Target
+**     else:
+**       return Patch
+**
+** Here is an equivalent algorithm restructured to show the actual
+** implementation:
+**
+** 01   define MergePatch(Target, Patch):
+** 02      if Patch is not an Object:
+** 03         return Patch
+** 04      else: // if Patch is an Object
+** 05         if Target is not an Object:
+** 06            Target = {}
+** 07      for each Name/Value pair in Patch:
+** 08         if Name exists in Target:
+** 09            if Value is null:
+** 10               remove the Name/Value pair from Target
+** 11            else
+** 12               Target[name] = MergePatch(Target[Name], Value)
+** 13         else if Value is not NULL:
+** 14            if Value is not an Object:
+** 15               Target[name] = Value
+** 16            else:
+** 17               Target[name] = MergePatch('{}',value)
+** 18      return Target
+**  |
+**  ^---- Line numbers referenced in comments in the implementation
+*/
+static int jsonMergePatch(
+  JsonParse *pTarget,      /* The JSON parser that contains the TARGET */
+  u32 iTarget,             /* Index of TARGET in pTarget->aBlob[] */
+  const JsonParse *pPatch, /* The PATCH */
+  u32 iPatch               /* Index of PATCH in pPatch->aBlob[] */
+){
+  u8 x;             /* Type of a single node */
+  u32 n, sz=0;      /* Return values from jsonbPayloadSize() */
+  u32 iTCursor;     /* Cursor position while scanning the target object */
+  u32 iTStart;      /* First label in the target object */
+  u32 iTEndBE;      /* Original first byte past end of target, before edit */
+  u32 iTEnd;        /* Current first byte past end of target */
+  u8 eTLabel;       /* Node type of the target label */
+  u32 iTLabel = 0;  /* Index of the label */
+  u32 nTLabel = 0;  /* Header size in bytes for the target label */
+  u32 szTLabel = 0; /* Size of the target label payload */
+  u32 iTValue = 0;  /* Index of the target value */
+  u32 nTValue = 0;  /* Header size of the target value */
+  u32 szTValue = 0; /* Payload size for the target value */
+
+  u32 iPCursor;     /* Cursor position while scanning the patch */
+  u32 iPEnd;        /* First byte past the end of the patch */
+  u8 ePLabel;       /* Node type of the patch label */
+  u32 iPLabel;      /* Start of patch label */
+  u32 nPLabel;      /* Size of header on the patch label */
+  u32 szPLabel;     /* Payload size of the patch label */
+  u32 iPValue;      /* Start of patch value */
+  u32 nPValue;      /* Header size for the patch value */
+  u32 szPValue;     /* Payload size of the patch value */
+
+  assert( iTarget>=0 && iTarget<pTarget->nBlob );
+  assert( iPatch>=0 && iPatch<pPatch->nBlob );
+  x = pPatch->aBlob[iPatch] & 0x0f;
+  if( x!=JSONB_OBJECT ){  /* Algorithm line 02 */
+    u32 szPatch;        /* Total size of the patch, header+payload */
+    u32 szTarget;       /* Total size of the target, header+payload */
+    n = jsonbPayloadSize(pPatch, iPatch, &sz);
+    szPatch = n+sz;
+    sz = 0;
+    n = jsonbPayloadSize(pTarget, iTarget, &sz);
+    szTarget = n+sz;
+    jsonBlobEdit(pTarget, iTarget, szTarget, pPatch->aBlob+iPatch, szPatch);
+    return pTarget->oom ? JSON_MERGE_OOM : JSON_MERGE_OK;  /* Line 03 */
+  }
+  x = pTarget->aBlob[iTarget] & 0x0f;
+  if( x!=JSONB_OBJECT ){  /* Algorithm line 05 */
+    n = jsonbPayloadSize(pTarget, iTarget, &sz);
+    jsonBlobEdit(pTarget, iTarget+n, sz, 0, 0);
+    x = pTarget->aBlob[iTarget];
+    pTarget->aBlob[iTarget] = (x & 0xf0) | JSONB_OBJECT;
+  }
+  n = jsonbPayloadSize(pPatch, iPatch, &sz);
+  if( NEVER(n==0) ) return JSON_MERGE_BADPATCH;
+  iPCursor = iPatch+n;
+  iPEnd = iPCursor+sz;
+  n = jsonbPayloadSize(pTarget, iTarget, &sz);
+  if( NEVER(n==0) ) return JSON_MERGE_BADTARGET;
+  iTStart = iTarget+n;
+  iTEndBE = iTStart+sz;
+
+  while( iPCursor<iPEnd ){  /* Algorithm line 07 */
+    iPLabel = iPCursor;
+    ePLabel = pPatch->aBlob[iPCursor] & 0x0f;
+    if( ePLabel<JSONB_TEXT || ePLabel>JSONB_TEXTRAW ){
+      return JSON_MERGE_BADPATCH;
+    }
+    nPLabel = jsonbPayloadSize(pPatch, iPCursor, &szPLabel);
+    if( nPLabel==0 ) return JSON_MERGE_BADPATCH;
+    iPValue = iPCursor + nPLabel + szPLabel;
+    if( iPValue>=iPEnd ) return JSON_MERGE_BADPATCH;
+    nPValue = jsonbPayloadSize(pPatch, iPValue, &szPValue);
+    if( nPValue==0 ) return JSON_MERGE_BADPATCH;
+    iPCursor = iPValue + nPValue + szPValue;
+    if( iPCursor>iPEnd ) return JSON_MERGE_BADPATCH;
+
+    iTCursor = iTStart;
+    iTEnd = iTEndBE + pTarget->delta;
+    while( iTCursor<iTEnd ){
+      int isEqual;   /* true if the patch and target labels match */
+      iTLabel = iTCursor;
+      eTLabel = pTarget->aBlob[iTCursor] & 0x0f;
+      if( eTLabel<JSONB_TEXT || eTLabel>JSONB_TEXTRAW ){
+        return JSON_MERGE_BADTARGET;
+      }
+      nTLabel = jsonbPayloadSize(pTarget, iTCursor, &szTLabel);
+      if( nTLabel==0 ) return JSON_MERGE_BADTARGET;
+      iTValue = iTLabel + nTLabel + szTLabel;
+      if( iTValue>=iTEnd ) return JSON_MERGE_BADTARGET;
+      nTValue = jsonbPayloadSize(pTarget, iTValue, &szTValue);
+      if( nTValue==0 ) return JSON_MERGE_BADTARGET;
+      if( iTValue + nTValue + szTValue > iTEnd ) return JSON_MERGE_BADTARGET;
+      isEqual = jsonLabelCompare(
+                   (const char*)&pPatch->aBlob[iPLabel+nPLabel],
+                   szPLabel,
+                   (ePLabel==JSONB_TEXT || ePLabel==JSONB_TEXTRAW),
+                   (const char*)&pTarget->aBlob[iTLabel+nTLabel],
+                   szTLabel,
+                   (eTLabel==JSONB_TEXT || eTLabel==JSONB_TEXTRAW));
+      if( isEqual ) break;
+      iTCursor = iTValue + nTValue + szTValue;
+    }
+    x = pPatch->aBlob[iPValue] & 0x0f;
+    if( iTCursor<iTEnd ){
+      /* A match was found.  Algorithm line 08 */
+      if( x==0 ){
+        /* Patch value is NULL.  Algorithm line 09 */
+        jsonBlobEdit(pTarget, iTLabel, nTLabel+szTLabel+nTValue+szTValue, 0,0);
+        /*  vvvvvv----- No OOM on a delete-only edit */
+        if( NEVER(pTarget->oom) ) return JSON_MERGE_OOM;
+      }else{
+        /* Algorithm line 12 */
+        int rc, savedDelta = pTarget->delta;
+        pTarget->delta = 0;
+        rc = jsonMergePatch(pTarget, iTValue, pPatch, iPValue);
+        if( rc ) return rc;
+        pTarget->delta += savedDelta;
+      }
+    }else if( x>0 ){  /* Algorithm line 13 */
+      /* No match and patch value is not NULL */
+      u32 szNew = szPLabel+nPLabel;
+      if( (pPatch->aBlob[iPValue] & 0x0f)!=JSONB_OBJECT ){  /* Line 14 */
+        jsonBlobEdit(pTarget, iTEnd, 0, 0, szPValue+nPValue+szNew);
+        if( pTarget->oom ) return JSON_MERGE_OOM;
+        memcpy(&pTarget->aBlob[iTEnd], &pPatch->aBlob[iPLabel], szNew);
+        memcpy(&pTarget->aBlob[iTEnd+szNew],
+               &pPatch->aBlob[iPValue], szPValue+nPValue);
+      }else{
+        int rc, savedDelta;
+        jsonBlobEdit(pTarget, iTEnd, 0, 0, szNew+1);
+        if( pTarget->oom ) return JSON_MERGE_OOM;
+        memcpy(&pTarget->aBlob[iTEnd], &pPatch->aBlob[iPLabel], szNew);
+        pTarget->aBlob[iTEnd+szNew] = 0x00;
+        savedDelta = pTarget->delta;
+        pTarget->delta = 0;
+        rc = jsonMergePatch(pTarget, iTEnd+szNew,pPatch,iPValue);
+        if( rc ) return rc;
+        pTarget->delta += savedDelta;
+      }
+    }
+  }
+  if( pTarget->delta ) jsonAfterEditSizeAdjust(pTarget, iTarget);
+  return pTarget->oom ? JSON_MERGE_OOM : JSON_MERGE_OK;
+}
+
+
+/*
+** Implementation of the json_mergepatch(JSON1,JSON2) function.  Return a JSON
+** object that is the result of running the RFC 7396 MergePatch() algorithm
+** on the two arguments.
+*/
+static void jsonPatchFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *pTarget;    /* The TARGET */
+  JsonParse *pPatch;     /* The PATCH */
+  int rc;                /* Result code */
+
+  UNUSED_PARAMETER(argc);
+  assert( argc==2 );
+  pTarget = jsonParseFuncArg(ctx, argv[0], JSON_EDITABLE);
+  if( pTarget==0 ) return;
+  pPatch = jsonParseFuncArg(ctx, argv[1], 0);
+  if( pPatch ){
+    rc = jsonMergePatch(pTarget, 0, pPatch, 0);
+    if( rc==JSON_MERGE_OK ){
+      jsonReturnParse(ctx, pTarget);
+    }else if( rc==JSON_MERGE_OOM ){
+      sqlite3_result_error_nomem(ctx);
+    }else{
+      sqlite3_result_error(ctx, "malformed JSON", -1);
+    }
+    jsonParseFree(pPatch);
+  }
+  jsonParseFree(pTarget);
+}
+
+
+/*
+** Implementation of the json_object(NAME,VALUE,...) function.  Return a JSON
+** object that contains all name/value given in arguments.  Or if any name
+** is not a string or if any value is a BLOB, throw an error.
+*/
+static void jsonObjectFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  int i;
+  JsonString jx;
+  const char *z;
+  u32 n;
+
+  if( argc&1 ){
+    sqlite3_result_error(ctx, "json_object() requires an even number "
+                                  "of arguments", -1);
+    return;
+  }
+  jsonStringInit(&jx, ctx);
+  jsonAppendChar(&jx, '{');
+  for(i=0; i<argc; i+=2){
+    if( sqlite3_value_type(argv[i])!=SQLITE_TEXT ){
+      sqlite3_result_error(ctx, "json_object() labels must be TEXT", -1);
+      jsonStringReset(&jx);
+      return;
+    }
+    jsonAppendSeparator(&jx);
+    z = (const char*)sqlite3_value_text(argv[i]);
+    n = sqlite3_value_bytes(argv[i]);
+    jsonAppendString(&jx, z, n);
+    jsonAppendChar(&jx, ':');
+    jsonAppendSqlValue(&jx, argv[i+1]);
+  }
+  jsonAppendChar(&jx, '}');
+  jsonReturnString(&jx, 0, 0);
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+
+
+/*
+** json_remove(JSON, PATH, ...)
+**
+** Remove the named elements from JSON and return the result.  malformed
+** JSON or PATH arguments result in an error.
+*/
+static void jsonRemoveFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;          /* The parse */
+  const char *zPath = 0; /* Path of element to be removed */
+  int i;                 /* Loop counter */
+  u32 rc;                /* Subroutine return code */
+
+  if( argc<1 ) return;
+  p = jsonParseFuncArg(ctx, argv[0], argc>1 ? JSON_EDITABLE : 0);
+  if( p==0 ) return;
+  for(i=1; i<argc; i++){
+    zPath = (const char*)sqlite3_value_text(argv[i]);
+    if( zPath==0 ){
+      goto json_remove_done;
+    }
+    if( zPath[0]!='$' ){
+      goto json_remove_patherror;
+    }
+    if( zPath[1]==0 ){
+      /* json_remove(j,'$') returns NULL */
+      goto json_remove_done;
+    }
+    p->eEdit = JEDIT_DEL;
+    p->delta = 0;
+    rc = jsonLookupStep(p, 0, zPath+1, 0);
+    if( JSON_LOOKUP_ISERROR(rc) ){
+      if( rc==JSON_LOOKUP_NOTFOUND ){
+        continue;  /* No-op */
+      }else if( rc==JSON_LOOKUP_PATHERROR ){
+        jsonBadPathError(ctx, zPath);
+      }else{
+        sqlite3_result_error(ctx, "malformed JSON", -1);
+      }
+      goto json_remove_done;
+    }
+  }
+  jsonReturnParse(ctx, p);
+  jsonParseFree(p);
+  return;
+
+json_remove_patherror:
+  jsonBadPathError(ctx, zPath);
+
+json_remove_done:
+  jsonParseFree(p);
+  return;
+}
+
+/*
+** json_replace(JSON, PATH, VALUE, ...)
+**
+** Replace the value at PATH with VALUE.  If PATH does not already exist,
+** this routine is a no-op.  If JSON or PATH is malformed, throw an error.
+*/
+static void jsonReplaceFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  if( argc<1 ) return;
+  if( (argc&1)==0 ) {
+    jsonWrongNumArgs(ctx, "replace");
+    return;
+  }
+  jsonInsertIntoBlob(ctx, argc, argv, JEDIT_REPL);
+}
+
+
+/*
+** json_set(JSON, PATH, VALUE, ...)
+**
+** Set the value at PATH to VALUE.  Create the PATH if it does not already
+** exist.  Overwrite existing values that do exist.
+** If JSON or PATH is malformed, throw an error.
+**
+** json_insert(JSON, PATH, VALUE, ...)
+**
+** Create PATH and initialize it to VALUE.  If PATH already exists, this
+** routine is a no-op.  If JSON or PATH is malformed, throw an error.
+*/
+static void jsonSetFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+
+  int flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+  int bIsSet = (flags&JSON_ISSET)!=0;
+
+  if( argc<1 ) return;
+  if( (argc&1)==0 ) {
+    jsonWrongNumArgs(ctx, bIsSet ? "set" : "insert");
+    return;
+  }
+  jsonInsertIntoBlob(ctx, argc, argv, bIsSet ? JEDIT_SET : JEDIT_INS);
+}
+
+/*
+** json_type(JSON)
+** json_type(JSON, PATH)
+**
+** Return the top-level "type" of a JSON string.  json_type() raises an
+** error if either the JSON or PATH inputs are not well-formed.
+*/
+static void jsonTypeFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;          /* The parse */
+  const char *zPath = 0;
+  u32 i;
+
+  p = jsonParseFuncArg(ctx, argv[0], 0);
+  if( p==0 ) return;
+  if( argc==2 ){
+    zPath = (const char*)sqlite3_value_text(argv[1]);
+    if( zPath==0 ) goto json_type_done;
+    if( zPath[0]!='$' ){
+      jsonBadPathError(ctx, zPath);
+      goto json_type_done;
+    }
+    i = jsonLookupStep(p, 0, zPath+1, 0);
+    if( JSON_LOOKUP_ISERROR(i) ){
+      if( i==JSON_LOOKUP_NOTFOUND ){
+        /* no-op */
+      }else if( i==JSON_LOOKUP_PATHERROR ){
+        jsonBadPathError(ctx, zPath);
+      }else{
+        sqlite3_result_error(ctx, "malformed JSON", -1);
+      }
+      goto json_type_done;
+    }
+  }else{
+    i = 0;
+  }
+  sqlite3_result_text(ctx, jsonbType[p->aBlob[i]&0x0f], -1, SQLITE_STATIC);
+json_type_done:
+  jsonParseFree(p);
+}
+
+/*
+** json_pretty(JSON)
+** json_pretty(JSON, INDENT)
+**
+** Return text that is a pretty-printed rendering of the input JSON.
+** If the argument is not valid JSON, return NULL.
+**
+** The INDENT argument is text that is used for indentation.  If omitted,
+** it defaults to four spaces (the same as PostgreSQL).
+*/
+static void jsonPrettyFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonString s;          /* The output string */
+  JsonPretty x;          /* Pretty printing context */
+
+  memset(&x, 0, sizeof(x));
+  x.pParse = jsonParseFuncArg(ctx, argv[0], 0);
+  if( x.pParse==0 ) return;
+  x.pOut = &s;
+  jsonStringInit(&s, ctx);
+  if( argc==1 || (x.zIndent = (const char*)sqlite3_value_text(argv[1]))==0 ){
+    x.zIndent = "    ";
+    x.szIndent = 4;
+  }else{
+    x.szIndent = (u32)strlen(x.zIndent);
+  }
+  jsonTranslateBlobToPrettyText(&x, 0);
+  jsonReturnString(&s, 0, 0);
+  jsonParseFree(x.pParse);
+}
+
+/*
+** json_valid(JSON)
+** json_valid(JSON, FLAGS)
+**
+** Check the JSON argument to see if it is well-formed.  The FLAGS argument
+** encodes the various constraints on what is meant by "well-formed":
+**
+**     0x01      Canonical RFC-8259 JSON text
+**     0x02      JSON text with optional JSON-5 extensions
+**     0x04      Superficially appears to be JSONB
+**     0x08      Strictly well-formed JSONB
+**
+** If the FLAGS argument is omitted, it defaults to 1.  Useful values for
+** FLAGS include:
+**
+**    1          Strict canonical JSON text
+**    2          JSON text perhaps with JSON-5 extensions
+**    4          Superficially appears to be JSONB
+**    5          Canonical JSON text or superficial JSONB
+**    6          JSON-5 text or superficial JSONB
+**    8          Strict JSONB
+**    9          Canonical JSON text or strict JSONB
+**    10         JSON-5 text or strict JSONB
+**
+** Other flag combinations are redundant.  For example, every canonical
+** JSON text is also well-formed JSON-5 text, so FLAG values 2 and 3
+** are the same.  Similarly, any input that passes a strict JSONB validation
+** will also pass the superficial validation so 12 through 15 are the same
+** as 8 through 11 respectively.
+**
+** This routine runs in linear time to validate text and when doing strict
+** JSONB validation.  Superficial JSONB validation is constant time,
+** assuming the BLOB is already in memory.  The performance advantage
+** of superficial JSONB validation is why that option is provided.
+** Application developers can choose to do fast superficial validation or
+** slower strict validation, according to their specific needs.
+**
+** Only the lower four bits of the FLAGS argument are currently used.
+** Higher bits are reserved for future expansion.   To facilitate
+** compatibility, the current implementation raises an error if any bit
+** in FLAGS is set other than the lower four bits.
+**
+** The original circa 2015 implementation of the JSON routines in
+** SQLite only supported canonical RFC-8259 JSON text and the json_valid()
+** function only accepted one argument.  That is why the default value
+** for the FLAGS argument is 1, since FLAGS=1 causes this routine to only
+** recognize canonical RFC-8259 JSON text as valid.  The extra FLAGS
+** argument was added when the JSON routines were extended to support
+** JSON5-like extensions and binary JSONB stored in BLOBs.
+**
+** Return Values:
+**
+**   *   Raise an error if FLAGS is outside the range of 1 to 15.
+**   *   Return NULL if the input is NULL
+**   *   Return 1 if the input is well-formed.
+**   *   Return 0 if the input is not well-formed.
+*/
+static void jsonValidFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonParse *p;          /* The parse */
+  u8 flags = 1;
+  u8 res = 0;
+  if( argc==2 ){
+    i64 f = sqlite3_value_int64(argv[1]);
+    if( f<1 || f>15 ){
+      sqlite3_result_error(ctx, "FLAGS parameter to json_valid() must be"
+                                " between 1 and 15", -1);
+      return;
+    }
+    flags = f & 0x0f;
+  }
+  switch( sqlite3_value_type(argv[0]) ){
+    case SQLITE_NULL: {
+#ifdef SQLITE_LEGACY_JSON_VALID
+      /* Incorrect legacy behavior was to return FALSE for a NULL input */
+      sqlite3_result_int(ctx, 0);
+#endif
+      return;
+    }
+    case SQLITE_BLOB: {
+      if( jsonFuncArgMightBeBinary(argv[0]) ){
+        if( flags & 0x04 ){
+          /* Superficial checking only - accomplished by the
+          ** jsonFuncArgMightBeBinary() call above. */
+          res = 1;
+        }else if( flags & 0x08 ){
+          /* Strict checking.  Check by translating BLOB->TEXT->BLOB.  If
+          ** no errors occur, call that a "strict check". */
+          JsonParse px;
+          u32 iErr;
+          memset(&px, 0, sizeof(px));
+          px.aBlob = (u8*)sqlite3_value_blob(argv[0]);
+          px.nBlob = sqlite3_value_bytes(argv[0]);
+          iErr = jsonbValidityCheck(&px, 0, px.nBlob, 1);
+          res = iErr==0;
+        }
+        break;
+      }
+      /* Fall through into interpreting the input as text.  See note
+      ** above at tag-20240123-a. */
+      /* no break */ deliberate_fall_through
+    }
+    default: {
+      JsonParse px;
+      if( (flags & 0x3)==0 ) break;
+      memset(&px, 0, sizeof(px));
+
+      p = jsonParseFuncArg(ctx, argv[0], JSON_KEEPERROR);
+      if( p ){
+        if( p->oom ){
+          sqlite3_result_error_nomem(ctx);
+        }else if( p->nErr ){
+          /* no-op */
+        }else if( (flags & 0x02)!=0 || p->hasNonstd==0 ){
+          res = 1;
+        }
+        jsonParseFree(p);
+      }else{
+        sqlite3_result_error_nomem(ctx);
+      }
+      break;
+    }
+  }
+  sqlite3_result_int(ctx, res);
+}
+
+/*
+** json_error_position(JSON)
+**
+** If the argument is NULL, return NULL
+**
+** If the argument is BLOB, do a full validity check and return non-zero
+** if the check fails.  The return value is the approximate 1-based offset
+** to the byte of the element that contains the first error.
+**
+** Otherwise interpret the argument is TEXT (even if it is numeric) and
+** return the 1-based character position for where the parser first recognized
+** that the input was not valid JSON, or return 0 if the input text looks
+** ok.  JSON-5 extensions are accepted.
+*/
+static void jsonErrorFunc(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  i64 iErrPos = 0;       /* Error position to be returned */
+  JsonParse s;
+
+  assert( argc==1 );
+  UNUSED_PARAMETER(argc);
+  memset(&s, 0, sizeof(s));
+  s.db = sqlite3_context_db_handle(ctx);
+  if( jsonFuncArgMightBeBinary(argv[0]) ){
+    s.aBlob = (u8*)sqlite3_value_blob(argv[0]);
+    s.nBlob = sqlite3_value_bytes(argv[0]);
+    iErrPos = (i64)jsonbValidityCheck(&s, 0, s.nBlob, 1);
+  }else{
+    s.zJson = (char*)sqlite3_value_text(argv[0]);
+    if( s.zJson==0 ) return;  /* NULL input or OOM */
+    s.nJson = sqlite3_value_bytes(argv[0]);
+    if( jsonConvertTextToBlob(&s,0) ){
+      if( s.oom ){
+        iErrPos = -1;
+      }else{
+        /* Convert byte-offset s.iErr into a character offset */
+        u32 k;
+        assert( s.zJson!=0 );  /* Because s.oom is false */
+        for(k=0; k<s.iErr && ALWAYS(s.zJson[k]); k++){
+          if( (s.zJson[k] & 0xc0)!=0x80 ) iErrPos++;
+        }
+        iErrPos++;
+      }
+    }
+  }
+  jsonParseReset(&s);
+  if( iErrPos<0 ){
+    sqlite3_result_error_nomem(ctx);
+  }else{
+    sqlite3_result_int64(ctx, iErrPos);
+  }
+}
+
+/****************************************************************************
+** Aggregate SQL function implementations
+****************************************************************************/
+/*
+** json_group_array(VALUE)
+**
+** Return a JSON array composed of all values in the aggregate.
+*/
+static void jsonArrayStep(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonString *pStr;
+  UNUSED_PARAMETER(argc);
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, sizeof(*pStr));
+  if( pStr ){
+    if( pStr->zBuf==0 ){
+      jsonStringInit(pStr, ctx);
+      jsonAppendChar(pStr, '[');
+    }else if( pStr->nUsed>1 ){
+      jsonAppendChar(pStr, ',');
+    }
+    pStr->pCtx = ctx;
+    jsonAppendSqlValue(pStr, argv[0]);
+  }
+}
+static void jsonArrayCompute(sqlite3_context *ctx, int isFinal){
+  JsonString *pStr;
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, 0);
+  if( pStr ){
+    int flags;
+    pStr->pCtx = ctx;
+    jsonAppendChar(pStr, ']');
+    flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+    if( pStr->eErr ){
+      jsonReturnString(pStr, 0, 0);
+      return;
+    }else if( flags & JSON_BLOB ){
+      jsonReturnStringAsBlob(pStr);
+      if( isFinal ){
+        if( !pStr->bStatic ) sqlite3RCStrUnref(pStr->zBuf);
+      }else{
+        jsonStringTrimOneChar(pStr);
+      }
+      return;
+    }else if( isFinal ){
+      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed,
+                          pStr->bStatic ? SQLITE_TRANSIENT :
+                              sqlite3RCStrUnref);
+      pStr->bStatic = 1;
+    }else{
+      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed, SQLITE_TRANSIENT);
+      jsonStringTrimOneChar(pStr);
+    }
+  }else{
+    sqlite3_result_text(ctx, "[]", 2, SQLITE_STATIC);
+  }
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+static void jsonArrayValue(sqlite3_context *ctx){
+  jsonArrayCompute(ctx, 0);
+}
+static void jsonArrayFinal(sqlite3_context *ctx){
+  jsonArrayCompute(ctx, 1);
+}
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+/*
+** This method works for both json_group_array() and json_group_object().
+** It works by removing the first element of the group by searching forward
+** to the first comma (",") that is not within a string and deleting all
+** text through that comma.
+*/
+static void jsonGroupInverse(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  unsigned int i;
+  int inStr = 0;
+  int nNest = 0;
+  char *z;
+  char c;
+  JsonString *pStr;
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(argv);
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, 0);
+#ifdef NEVER
+  /* pStr is always non-NULL since jsonArrayStep() or jsonObjectStep() will
+  ** always have been called to initialize it */
+  if( NEVER(!pStr) ) return;
+#endif
+  z = pStr->zBuf;
+  for(i=1; i<pStr->nUsed && ((c = z[i])!=',' || inStr || nNest); i++){
+    if( c=='"' ){
+      inStr = !inStr;
+    }else if( c=='\\' ){
+      i++;
+    }else if( !inStr ){
+      if( c=='{' || c=='[' ) nNest++;
+      if( c=='}' || c==']' ) nNest--;
+    }
+  }
+  if( i<pStr->nUsed ){
+    pStr->nUsed -= i;
+    memmove(&z[1], &z[i+1], (size_t)pStr->nUsed-1);
+    z[pStr->nUsed] = 0;
+  }else{
+    pStr->nUsed = 1;
+  }
+}
+#else
+# define jsonGroupInverse 0
+#endif
+
+
+/*
+** json_group_obj(NAME,VALUE)
+**
+** Return a JSON object composed of all names and values in the aggregate.
+*/
+static void jsonObjectStep(
+  sqlite3_context *ctx,
+  int argc,
+  sqlite3_value **argv
+){
+  JsonString *pStr;
+  const char *z;
+  u32 n;
+  UNUSED_PARAMETER(argc);
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, sizeof(*pStr));
+  if( pStr ){
+    if( pStr->zBuf==0 ){
+      jsonStringInit(pStr, ctx);
+      jsonAppendChar(pStr, '{');
+    }else if( pStr->nUsed>1 ){
+      jsonAppendChar(pStr, ',');
+    }
+    pStr->pCtx = ctx;
+    z = (const char*)sqlite3_value_text(argv[0]);
+    n = sqlite3Strlen30(z);
+    jsonAppendString(pStr, z, n);
+    jsonAppendChar(pStr, ':');
+    jsonAppendSqlValue(pStr, argv[1]);
+  }
+}
+static void jsonObjectCompute(sqlite3_context *ctx, int isFinal){
+  JsonString *pStr;
+  pStr = (JsonString*)sqlite3_aggregate_context(ctx, 0);
+  if( pStr ){
+    int flags;
+    jsonAppendChar(pStr, '}');
+    pStr->pCtx = ctx;
+    flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
+    if( pStr->eErr ){
+      jsonReturnString(pStr, 0, 0);
+      return;
+    }else if( flags & JSON_BLOB ){
+      jsonReturnStringAsBlob(pStr);
+      if( isFinal ){
+        if( !pStr->bStatic ) sqlite3RCStrUnref(pStr->zBuf);
+      }else{
+        jsonStringTrimOneChar(pStr);
+      }
+      return;
+    }else if( isFinal ){
+      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed,
+                          pStr->bStatic ? SQLITE_TRANSIENT :
+                          sqlite3RCStrUnref);
+      pStr->bStatic = 1;
+    }else{
+      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed, SQLITE_TRANSIENT);
+      jsonStringTrimOneChar(pStr);
+    }
+  }else{
+    sqlite3_result_text(ctx, "{}", 2, SQLITE_STATIC);
+  }
+  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+}
+static void jsonObjectValue(sqlite3_context *ctx){
+  jsonObjectCompute(ctx, 0);
+}
+static void jsonObjectFinal(sqlite3_context *ctx){
+  jsonObjectCompute(ctx, 1);
+}
+
+
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/****************************************************************************
+** The json_each virtual table
+****************************************************************************/
+typedef struct JsonParent JsonParent;
+struct JsonParent {
+  u32 iHead;                 /* Start of object or array */
+  u32 iValue;                /* Start of the value */
+  u32 iEnd;                  /* First byte past the end */
+  u32 nPath;                 /* Length of path */
+  i64 iKey;                  /* Key for JSONB_ARRAY */
+};
+
+typedef struct JsonEachCursor JsonEachCursor;
+struct JsonEachCursor {
+  sqlite3_vtab_cursor base;  /* Base class - must be first */
+  u32 iRowid;                /* The rowid */
+  u32 i;                     /* Index in sParse.aBlob[] of current row */
+  u32 iEnd;                  /* EOF when i equals or exceeds this value */
+  u32 nRoot;                 /* Size of the root path in bytes */
+  u8 eType;                  /* Type of the container for element i */
+  u8 bRecursive;             /* True for json_tree().  False for json_each() */
+  u32 nParent;               /* Current nesting depth */
+  u32 nParentAlloc;          /* Space allocated for aParent[] */
+  JsonParent *aParent;       /* Parent elements of i */
+  sqlite3 *db;               /* Database connection */
+  JsonString path;           /* Current path */
+  JsonParse sParse;          /* Parse of the input JSON */
+};
+typedef struct JsonEachConnection JsonEachConnection;
+struct JsonEachConnection {
+  sqlite3_vtab base;         /* Base class - must be first */
+  sqlite3 *db;               /* Database connection */
+};
+
+
+/* Constructor for the json_each virtual table */
+static int jsonEachConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  JsonEachConnection *pNew;
+  int rc;
+
+/* Column numbers */
+#define JEACH_KEY     0
+#define JEACH_VALUE   1
+#define JEACH_TYPE    2
+#define JEACH_ATOM    3
+#define JEACH_ID      4
+#define JEACH_PARENT  5
+#define JEACH_FULLKEY 6
+#define JEACH_PATH    7
+/* The xBestIndex method assumes that the JSON and ROOT columns are
+** the last two columns in the table.  Should this ever changes, be
+** sure to update the xBestIndex method. */
+#define JEACH_JSON    8
+#define JEACH_ROOT    9
+
+  UNUSED_PARAMETER(pzErr);
+  UNUSED_PARAMETER(argv);
+  UNUSED_PARAMETER(argc);
+  UNUSED_PARAMETER(pAux);
+  rc = sqlite3_declare_vtab(db,
+     "CREATE TABLE x(key,value,type,atom,id,parent,fullkey,path,"
+                    "json HIDDEN,root HIDDEN)");
+  if( rc==SQLITE_OK ){
+    pNew = (JsonEachConnection*)sqlite3DbMallocZero(db, sizeof(*pNew));
+    *ppVtab = (sqlite3_vtab*)pNew;
+    if( pNew==0 ) return SQLITE_NOMEM;
+    sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
+    pNew->db = db;
+  }
+  return rc;
+}
+
+/* destructor for json_each virtual table */
+static int jsonEachDisconnect(sqlite3_vtab *pVtab){
+  JsonEachConnection *p = (JsonEachConnection*)pVtab;
+  sqlite3DbFree(p->db, pVtab);
+  return SQLITE_OK;
+}
+
+/* constructor for a JsonEachCursor object for json_each(). */
+static int jsonEachOpenEach(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+  JsonEachConnection *pVtab = (JsonEachConnection*)p;
+  JsonEachCursor *pCur;
+
+  UNUSED_PARAMETER(p);
+  pCur = sqlite3DbMallocZero(pVtab->db, sizeof(*pCur));
+  if( pCur==0 ) return SQLITE_NOMEM;
+  pCur->db = pVtab->db;
+  jsonStringZero(&pCur->path);
+  *ppCursor = &pCur->base;
+  return SQLITE_OK;
+}
+
+/* constructor for a JsonEachCursor object for json_tree(). */
+static int jsonEachOpenTree(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+  int rc = jsonEachOpenEach(p, ppCursor);
+  if( rc==SQLITE_OK ){
+    JsonEachCursor *pCur = (JsonEachCursor*)*ppCursor;
+    pCur->bRecursive = 1;
+  }
+  return rc;
+}
+
+/* Reset a JsonEachCursor back to its original state.  Free any memory
+** held. */
+static void jsonEachCursorReset(JsonEachCursor *p){
+  jsonParseReset(&p->sParse);
+  jsonStringReset(&p->path);
+  sqlite3DbFree(p->db, p->aParent);
+  p->iRowid = 0;
+  p->i = 0;
+  p->aParent = 0;
+  p->nParent = 0;
+  p->nParentAlloc = 0;
+  p->iEnd = 0;
+  p->eType = 0;
+}
+
+/* Destructor for a jsonEachCursor object */
+static int jsonEachClose(sqlite3_vtab_cursor *cur){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  jsonEachCursorReset(p);
+
+  sqlite3DbFree(p->db, cur);
+  return SQLITE_OK;
+}
+
+/* Return TRUE if the jsonEachCursor object has been advanced off the end
+** of the JSON object */
+static int jsonEachEof(sqlite3_vtab_cursor *cur){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  return p->i >= p->iEnd;
+}
+
+/*
+** If the cursor is currently pointing at the label of a object entry,
+** then return the index of the value.  For all other cases, return the
+** current pointer position, which is the value.
+*/
+static int jsonSkipLabel(JsonEachCursor *p){
+  if( p->eType==JSONB_OBJECT ){
+    u32 sz = 0;
+    u32 n = jsonbPayloadSize(&p->sParse, p->i, &sz);
+    return p->i + n + sz;
+  }else{
+    return p->i;
+  }
+}
+
+/*
+** Append the path name for the current element.
+*/
+static void jsonAppendPathName(JsonEachCursor *p){
+  assert( p->nParent>0 );
+  assert( p->eType==JSONB_ARRAY || p->eType==JSONB_OBJECT );
+  if( p->eType==JSONB_ARRAY ){
+    jsonPrintf(30, &p->path, "[%lld]", p->aParent[p->nParent-1].iKey);
+  }else{
+    u32 n, sz = 0, k, i;
+    const char *z;
+    int needQuote = 0;
+    n = jsonbPayloadSize(&p->sParse, p->i, &sz);
+    k = p->i + n;
+    z = (const char*)&p->sParse.aBlob[k];
+    if( sz==0 || !sqlite3Isalpha(z[0]) ){
+      needQuote = 1;
+    }else{
+      for(i=0; i<sz; i++){
+        if( !sqlite3Isalnum(z[i]) ){
+          needQuote = 1;
+          break;
+        }
+      }
+    }
+    if( needQuote ){
+      jsonPrintf(sz+4,&p->path,".\"%.*s\"", sz, z);
+    }else{
+      jsonPrintf(sz+2,&p->path,".%.*s", sz, z);
+    }
+  }
+}
+
+/* Advance the cursor to the next element for json_tree() */
+static int jsonEachNext(sqlite3_vtab_cursor *cur){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  int rc = SQLITE_OK;
+  if( p->bRecursive ){
+    u8 x;
+    u8 levelChange = 0;
+    u32 n, sz = 0;
+    u32 i = jsonSkipLabel(p);
+    x = p->sParse.aBlob[i] & 0x0f;
+    n = jsonbPayloadSize(&p->sParse, i, &sz);
+    if( x==JSONB_OBJECT || x==JSONB_ARRAY ){
+      JsonParent *pParent;
+      if( p->nParent>=p->nParentAlloc ){
+        JsonParent *pNew;
+        u64 nNew;
+        nNew = p->nParentAlloc*2 + 3;
+        pNew = sqlite3DbRealloc(p->db, p->aParent, sizeof(JsonParent)*nNew);
+        if( pNew==0 ) return SQLITE_NOMEM;
+        p->nParentAlloc = (u32)nNew;
+        p->aParent = pNew;
+      }
+      levelChange = 1;
+      pParent = &p->aParent[p->nParent];
+      pParent->iHead = p->i;
+      pParent->iValue = i;
+      pParent->iEnd = i + n + sz;
+      pParent->iKey = -1;
+      pParent->nPath = (u32)p->path.nUsed;
+      if( p->eType && p->nParent ){
+        jsonAppendPathName(p);
+        if( p->path.eErr ) rc = SQLITE_NOMEM;
+      }
+      p->nParent++;
+      p->i = i + n;
+    }else{
+      p->i = i + n + sz;
+    }
+    while( p->nParent>0 && p->i >= p->aParent[p->nParent-1].iEnd ){
+      p->nParent--;
+      p->path.nUsed = p->aParent[p->nParent].nPath;
+      levelChange = 1;
+    }
+    if( levelChange ){
+      if( p->nParent>0 ){
+        JsonParent *pParent = &p->aParent[p->nParent-1];
+        u32 iVal = pParent->iValue;
+        p->eType = p->sParse.aBlob[iVal] & 0x0f;
+      }else{
+        p->eType = 0;
+      }
+    }
+  }else{
+    u32 n, sz = 0;
+    u32 i = jsonSkipLabel(p);
+    n = jsonbPayloadSize(&p->sParse, i, &sz);
+    p->i = i + n + sz;
+  }
+  if( p->eType==JSONB_ARRAY && p->nParent ){
+    p->aParent[p->nParent-1].iKey++;
+  }
+  p->iRowid++;
+  return rc;
+}
+
+/* Length of the path for rowid==0 in bRecursive mode.
+*/
+static int jsonEachPathLength(JsonEachCursor *p){
+  u32 n = p->path.nUsed;
+  char *z = p->path.zBuf;
+  if( p->iRowid==0 && p->bRecursive && n>=2 ){
+    while( n>1 ){
+      n--;
+      if( z[n]=='[' || z[n]=='.' ){
+        u32 x, sz = 0;
+        char cSaved = z[n];
+        z[n] = 0;
+        assert( p->sParse.eEdit==0 );
+        x = jsonLookupStep(&p->sParse, 0, z+1, 0);
+        z[n] = cSaved;
+        if( JSON_LOOKUP_ISERROR(x) ) continue;
+        if( x + jsonbPayloadSize(&p->sParse, x, &sz) == p->i ) break;
+      }
+    }
+  }
+  return n;
+}
+
+/* Return the value of a column */
+static int jsonEachColumn(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int iColumn                 /* Which column to return */
+){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  switch( iColumn ){
+    case JEACH_KEY: {
+      if( p->nParent==0 ){
+        u32 n, j;
+        if( p->nRoot==1 ) break;
+        j = jsonEachPathLength(p);
+        n = p->nRoot - j;
+        if( n==0 ){
+          break;
+        }else if( p->path.zBuf[j]=='[' ){
+          i64 x;
+          sqlite3Atoi64(&p->path.zBuf[j+1], &x, n-1, SQLITE_UTF8);
+          sqlite3_result_int64(ctx, x);
+        }else if( p->path.zBuf[j+1]=='"' ){
+          sqlite3_result_text(ctx, &p->path.zBuf[j+2], n-3, SQLITE_TRANSIENT);
+        }else{
+          sqlite3_result_text(ctx, &p->path.zBuf[j+1], n-1, SQLITE_TRANSIENT);
+        }
+        break;
+      }
+      if( p->eType==JSONB_OBJECT ){
+        jsonReturnFromBlob(&p->sParse, p->i, ctx, 1);
+      }else{
+        assert( p->eType==JSONB_ARRAY );
+        sqlite3_result_int64(ctx, p->aParent[p->nParent-1].iKey);
+      }
+      break;
+    }
+    case JEACH_VALUE: {
+      u32 i = jsonSkipLabel(p);
+      jsonReturnFromBlob(&p->sParse, i, ctx, 1);
+      if( (p->sParse.aBlob[i] & 0x0f)>=JSONB_ARRAY ){
+        sqlite3_result_subtype(ctx, JSON_SUBTYPE);
+      }
+      break;
+    }
+    case JEACH_TYPE: {
+      u32 i = jsonSkipLabel(p);
+      u8 eType = p->sParse.aBlob[i] & 0x0f;
+      sqlite3_result_text(ctx, jsonbType[eType], -1, SQLITE_STATIC);
+      break;
+    }
+    case JEACH_ATOM: {
+      u32 i = jsonSkipLabel(p);
+      if( (p->sParse.aBlob[i] & 0x0f)<JSONB_ARRAY ){
+        jsonReturnFromBlob(&p->sParse, i, ctx, 1);
+      }
+      break;
+    }
+    case JEACH_ID: {
+      sqlite3_result_int64(ctx, (sqlite3_int64)p->i);
+      break;
+    }
+    case JEACH_PARENT: {
+      if( p->nParent>0 && p->bRecursive ){
+        sqlite3_result_int64(ctx, p->aParent[p->nParent-1].iHead);
+      }
+      break;
+    }
+    case JEACH_FULLKEY: {
+      u64 nBase = p->path.nUsed;
+      if( p->nParent ) jsonAppendPathName(p);
+      sqlite3_result_text64(ctx, p->path.zBuf, p->path.nUsed,
+                            SQLITE_TRANSIENT, SQLITE_UTF8);
+      p->path.nUsed = nBase;
+      break;
+    }
+    case JEACH_PATH: {
+      u32 n = jsonEachPathLength(p);
+      sqlite3_result_text64(ctx, p->path.zBuf, n,
+                            SQLITE_TRANSIENT, SQLITE_UTF8);
+      break;
+    }
+    default: {
+      sqlite3_result_text(ctx, p->path.zBuf, p->nRoot, SQLITE_STATIC);
+      break;
+    }
+    case JEACH_JSON: {
+      if( p->sParse.zJson==0 ){
+        sqlite3_result_blob(ctx, p->sParse.aBlob, p->sParse.nBlob,
+                            SQLITE_TRANSIENT);
+      }else{
+        sqlite3_result_text(ctx, p->sParse.zJson, -1, SQLITE_TRANSIENT);
+      }
+      break;
+    }
+  }
+  return SQLITE_OK;
+}
+
+/* Return the current rowid value */
+static int jsonEachRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  *pRowid = p->iRowid;
+  return SQLITE_OK;
+}
+
+/* The query strategy is to look for an equality constraint on the json
+** column.  Without such a constraint, the table cannot operate.  idxNum is
+** 1 if the constraint is found, 3 if the constraint and zRoot are found,
+** and 0 otherwise.
+*/
+static int jsonEachBestIndex(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  int i;                     /* Loop counter or computed array index */
+  int aIdx[2];               /* Index of constraints for JSON and ROOT */
+  int unusableMask = 0;      /* Mask of unusable JSON and ROOT constraints */
+  int idxMask = 0;           /* Mask of usable == constraints JSON and ROOT */
+  const struct sqlite3_index_constraint *pConstraint;
+
+  /* This implementation assumes that JSON and ROOT are the last two
+  ** columns in the table */
+  assert( JEACH_ROOT == JEACH_JSON+1 );
+  UNUSED_PARAMETER(tab);
+  aIdx[0] = aIdx[1] = -1;
+  pConstraint = pIdxInfo->aConstraint;
+  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
+    int iCol;
+    int iMask;
+    if( pConstraint->iColumn < JEACH_JSON ) continue;
+    iCol = pConstraint->iColumn - JEACH_JSON;
+    assert( iCol==0 || iCol==1 );
+    testcase( iCol==0 );
+    iMask = 1 << iCol;
+    if( pConstraint->usable==0 ){
+      unusableMask |= iMask;
+    }else if( pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ ){
+      aIdx[iCol] = i;
+      idxMask |= iMask;
+    }
+  }
+  if( pIdxInfo->nOrderBy>0
+   && pIdxInfo->aOrderBy[0].iColumn<0
+   && pIdxInfo->aOrderBy[0].desc==0
+  ){
+    pIdxInfo->orderByConsumed = 1;
+  }
+
+  if( (unusableMask & ~idxMask)!=0 ){
+    /* If there are any unusable constraints on JSON or ROOT, then reject
+    ** this entire plan */
+    return SQLITE_CONSTRAINT;
+  }
+  if( aIdx[0]<0 ){
+    /* No JSON input.  Leave estimatedCost at the huge value that it was
+    ** initialized to to discourage the query planner from selecting this
+    ** plan. */
+    pIdxInfo->idxNum = 0;
+  }else{
+    pIdxInfo->estimatedCost = 1.0;
+    i = aIdx[0];
+    pIdxInfo->aConstraintUsage[i].argvIndex = 1;
+    pIdxInfo->aConstraintUsage[i].omit = 1;
+    if( aIdx[1]<0 ){
+      pIdxInfo->idxNum = 1;  /* Only JSON supplied.  Plan 1 */
+    }else{
+      i = aIdx[1];
+      pIdxInfo->aConstraintUsage[i].argvIndex = 2;
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      pIdxInfo->idxNum = 3;  /* Both JSON and ROOT are supplied.  Plan 3 */
+    }
+  }
+  return SQLITE_OK;
+}
+
+/* Start a search on a new JSON string */
+static int jsonEachFilter(
+  sqlite3_vtab_cursor *cur,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  JsonEachCursor *p = (JsonEachCursor*)cur;
+  const char *zRoot = 0;
+  u32 i, n, sz;
+
+  UNUSED_PARAMETER(idxStr);
+  UNUSED_PARAMETER(argc);
+  jsonEachCursorReset(p);
+  if( idxNum==0 ) return SQLITE_OK;
+  memset(&p->sParse, 0, sizeof(p->sParse));
+  p->sParse.nJPRef = 1;
+  p->sParse.db = p->db;
+  if( jsonFuncArgMightBeBinary(argv[0]) ){
+    p->sParse.nBlob = sqlite3_value_bytes(argv[0]);
+    p->sParse.aBlob = (u8*)sqlite3_value_blob(argv[0]);
+  }else{
+    p->sParse.zJson = (char*)sqlite3_value_text(argv[0]);
+    p->sParse.nJson = sqlite3_value_bytes(argv[0]);
+    if( p->sParse.zJson==0 ){
+      p->i = p->iEnd = 0;
+      return SQLITE_OK;
+    }
+    if( jsonConvertTextToBlob(&p->sParse, 0) ){
+      if( p->sParse.oom ){
+        return SQLITE_NOMEM;
+      }
+      goto json_each_malformed_input;
+    }
+  }
+  if( idxNum==3 ){
+    zRoot = (const char*)sqlite3_value_text(argv[1]);
+    if( zRoot==0 ) return SQLITE_OK;
+    if( zRoot[0]!='$' ){
+      sqlite3_free(cur->pVtab->zErrMsg);
+      cur->pVtab->zErrMsg = jsonBadPathError(0, zRoot);
+      jsonEachCursorReset(p);
+      return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
+    }
+    p->nRoot = sqlite3Strlen30(zRoot);
+    if( zRoot[1]==0 ){
+      i = p->i = 0;
+      p->eType = 0;
+    }else{
+      i = jsonLookupStep(&p->sParse, 0, zRoot+1, 0);
+      if( JSON_LOOKUP_ISERROR(i) ){
+        if( i==JSON_LOOKUP_NOTFOUND ){
+          p->i = 0;
+          p->eType = 0;
+          p->iEnd = 0;
+          return SQLITE_OK;
+        }
+        sqlite3_free(cur->pVtab->zErrMsg);
+        cur->pVtab->zErrMsg = jsonBadPathError(0, zRoot);
+        jsonEachCursorReset(p);
+        return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
+      }
+      if( p->sParse.iLabel ){
+        p->i = p->sParse.iLabel;
+        p->eType = JSONB_OBJECT;
+      }else{
+        p->i = i;
+        p->eType = JSONB_ARRAY;
+      }
+    }
+    jsonAppendRaw(&p->path, zRoot, p->nRoot);
+  }else{
+    i = p->i = 0;
+    p->eType = 0;
+    p->nRoot = 1;
+    jsonAppendRaw(&p->path, "$", 1);
+  }
+  p->nParent = 0;
+  n = jsonbPayloadSize(&p->sParse, i, &sz);
+  p->iEnd = i+n+sz;
+  if( (p->sParse.aBlob[i] & 0x0f)>=JSONB_ARRAY && !p->bRecursive ){
+    p->i = i + n;
+    p->eType = p->sParse.aBlob[i] & 0x0f;
+    p->aParent = sqlite3DbMallocZero(p->db, sizeof(JsonParent));
+    if( p->aParent==0 ) return SQLITE_NOMEM;
+    p->nParent = 1;
+    p->nParentAlloc = 1;
+    p->aParent[0].iKey = 0;
+    p->aParent[0].iEnd = p->iEnd;
+    p->aParent[0].iHead = p->i;
+    p->aParent[0].iValue = i;
+  }
+  return SQLITE_OK;
+
+json_each_malformed_input:
+  sqlite3_free(cur->pVtab->zErrMsg);
+  cur->pVtab->zErrMsg = sqlite3_mprintf("malformed JSON");
+  jsonEachCursorReset(p);
+  return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
+}
+
+/* The methods of the json_each virtual table */
+static sqlite3_module jsonEachModule = {
+  0,                         /* iVersion */
+  0,                         /* xCreate */
+  jsonEachConnect,           /* xConnect */
+  jsonEachBestIndex,         /* xBestIndex */
+  jsonEachDisconnect,        /* xDisconnect */
+  0,                         /* xDestroy */
+  jsonEachOpenEach,          /* xOpen - open a cursor */
+  jsonEachClose,             /* xClose - close a cursor */
+  jsonEachFilter,            /* xFilter - configure scan constraints */
+  jsonEachNext,              /* xNext - advance a cursor */
+  jsonEachEof,               /* xEof - check for end of scan */
+  jsonEachColumn,            /* xColumn - read data */
+  jsonEachRowid,             /* xRowid - read data */
+  0,                         /* xUpdate */
+  0,                         /* xBegin */
+  0,                         /* xSync */
+  0,                         /* xCommit */
+  0,                         /* xRollback */
+  0,                         /* xFindMethod */
+  0,                         /* xRename */
+  0,                         /* xSavepoint */
+  0,                         /* xRelease */
+  0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
+  0                          /* xIntegrity */
+};
+
+/* The methods of the json_tree virtual table. */
+static sqlite3_module jsonTreeModule = {
+  0,                         /* iVersion */
+  0,                         /* xCreate */
+  jsonEachConnect,           /* xConnect */
+  jsonEachBestIndex,         /* xBestIndex */
+  jsonEachDisconnect,        /* xDisconnect */
+  0,                         /* xDestroy */
+  jsonEachOpenTree,          /* xOpen - open a cursor */
+  jsonEachClose,             /* xClose - close a cursor */
+  jsonEachFilter,            /* xFilter - configure scan constraints */
+  jsonEachNext,              /* xNext - advance a cursor */
+  jsonEachEof,               /* xEof - check for end of scan */
+  jsonEachColumn,            /* xColumn - read data */
+  jsonEachRowid,             /* xRowid - read data */
+  0,                         /* xUpdate */
+  0,                         /* xBegin */
+  0,                         /* xSync */
+  0,                         /* xCommit */
+  0,                         /* xRollback */
+  0,                         /* xFindMethod */
+  0,                         /* xRename */
+  0,                         /* xSavepoint */
+  0,                         /* xRelease */
+  0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
+  0                          /* xIntegrity */
+};
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+#endif /* !defined(SQLITE_OMIT_JSON) */
+
+/*
+** Register JSON functions.
+*/
+SQLITE_PRIVATE void sqlite3RegisterJsonFunctions(void){
+#ifndef SQLITE_OMIT_JSON
+  static FuncDef aJsonFunc[] = {
+    /*   sqlite3_result_subtype() ----,  ,--- sqlite3_value_subtype()       */
+    /*                                |  |                                  */
+    /*             Uses cache ------, |  | ,---- Returns JSONB              */
+    /*                              | |  | |                                */
+    /*     Number of arguments ---, | |  | | ,--- Flags                     */
+    /*                            | | |  | | |                              */
+    JFUNCTION(json,               1,1,1, 0,0,0,          jsonRemoveFunc),
+    JFUNCTION(jsonb,              1,1,0, 0,1,0,          jsonRemoveFunc),
+    JFUNCTION(json_array,        -1,0,1, 1,0,0,          jsonArrayFunc),
+    JFUNCTION(jsonb_array,       -1,0,1, 1,1,0,          jsonArrayFunc),
+    JFUNCTION(json_array_length,  1,1,0, 0,0,0,          jsonArrayLengthFunc),
+    JFUNCTION(json_array_length,  2,1,0, 0,0,0,          jsonArrayLengthFunc),
+    JFUNCTION(json_error_position,1,1,0, 0,0,0,          jsonErrorFunc),
+    JFUNCTION(json_extract,      -1,1,1, 0,0,0,          jsonExtractFunc),
+    JFUNCTION(jsonb_extract,     -1,1,0, 0,1,0,          jsonExtractFunc),
+    JFUNCTION(->,                 2,1,1, 0,0,JSON_JSON,  jsonExtractFunc),
+    JFUNCTION(->>,                2,1,0, 0,0,JSON_SQL,   jsonExtractFunc),
+    JFUNCTION(json_insert,       -1,1,1, 1,0,0,          jsonSetFunc),
+    JFUNCTION(jsonb_insert,      -1,1,0, 1,1,0,          jsonSetFunc),
+    JFUNCTION(json_object,       -1,0,1, 1,0,0,          jsonObjectFunc),
+    JFUNCTION(jsonb_object,      -1,0,1, 1,1,0,          jsonObjectFunc),
+    JFUNCTION(json_patch,         2,1,1, 0,0,0,          jsonPatchFunc),
+    JFUNCTION(jsonb_patch,        2,1,0, 0,1,0,          jsonPatchFunc),
+    JFUNCTION(json_pretty,        1,1,0, 0,0,0,          jsonPrettyFunc),
+    JFUNCTION(json_pretty,        2,1,0, 0,0,0,          jsonPrettyFunc),
+    JFUNCTION(json_quote,         1,0,1, 1,0,0,          jsonQuoteFunc),
+    JFUNCTION(json_remove,       -1,1,1, 0,0,0,          jsonRemoveFunc),
+    JFUNCTION(jsonb_remove,      -1,1,0, 0,1,0,          jsonRemoveFunc),
+    JFUNCTION(json_replace,      -1,1,1, 1,0,0,          jsonReplaceFunc),
+    JFUNCTION(jsonb_replace,     -1,1,0, 1,1,0,          jsonReplaceFunc),
+    JFUNCTION(json_set,          -1,1,1, 1,0,JSON_ISSET, jsonSetFunc),
+    JFUNCTION(jsonb_set,         -1,1,0, 1,1,JSON_ISSET, jsonSetFunc),
+    JFUNCTION(json_type,          1,1,0, 0,0,0,          jsonTypeFunc),
+    JFUNCTION(json_type,          2,1,0, 0,0,0,          jsonTypeFunc),
+    JFUNCTION(json_valid,         1,1,0, 0,0,0,          jsonValidFunc),
+    JFUNCTION(json_valid,         2,1,0, 0,0,0,          jsonValidFunc),
+#if SQLITE_DEBUG
+    JFUNCTION(json_parse,         1,1,0, 0,0,0,          jsonParseFunc),
+#endif
+    WAGGREGATE(json_group_array,  1, 0, 0,
+       jsonArrayStep, jsonArrayFinal, jsonArrayValue, jsonGroupInverse,
+       SQLITE_SUBTYPE|SQLITE_RESULT_SUBTYPE|SQLITE_UTF8|
+       SQLITE_DETERMINISTIC),
+    WAGGREGATE(jsonb_group_array, 1, JSON_BLOB, 0,
+       jsonArrayStep, jsonArrayFinal, jsonArrayValue, jsonGroupInverse,
+       SQLITE_SUBTYPE|SQLITE_RESULT_SUBTYPE|SQLITE_UTF8|SQLITE_DETERMINISTIC),
+    WAGGREGATE(json_group_object, 2, 0, 0,
+       jsonObjectStep, jsonObjectFinal, jsonObjectValue, jsonGroupInverse,
+       SQLITE_SUBTYPE|SQLITE_RESULT_SUBTYPE|SQLITE_UTF8|SQLITE_DETERMINISTIC),
+    WAGGREGATE(jsonb_group_object,2, JSON_BLOB, 0,
+       jsonObjectStep, jsonObjectFinal, jsonObjectValue, jsonGroupInverse,
+       SQLITE_SUBTYPE|SQLITE_RESULT_SUBTYPE|SQLITE_UTF8|
+       SQLITE_DETERMINISTIC)
+  };
+  sqlite3InsertBuiltinFuncs(aJsonFunc, ArraySize(aJsonFunc));
+#endif
+}
+
+#if  !defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_JSON)
+/*
+** Register the JSON table-valued functions
+*/
+SQLITE_PRIVATE int sqlite3JsonTableFunctions(sqlite3 *db){
+  int rc = SQLITE_OK;
+  static const struct {
+    const char *zName;
+    sqlite3_module *pModule;
+  } aMod[] = {
+    { "json_each",            &jsonEachModule               },
+    { "json_tree",            &jsonTreeModule               },
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(aMod)/sizeof(aMod[0]) && rc==SQLITE_OK; i++){
+    rc = sqlite3_create_module(db, aMod[i].zName, aMod[i].pModule, 0);
+  }
+  return rc;
+}
+#endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) && !defined(SQLITE_OMIT_JSON) */
+
+/************** End of json.c ************************************************/
+/************** Begin file rtree.c *******************************************/
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code for implementations of the r-tree and r*-tree
+** algorithms packaged as an SQLite virtual table module.
+*/
+
+/*
+** Database Format of R-Tree Tables
+** --------------------------------
+**
+** The data structure for a single virtual r-tree table is stored in three
+** native SQLite tables declared as follows. In each case, the '%' character
+** in the table name is replaced with the user-supplied name of the r-tree
+** table.
+**
+**   CREATE TABLE %_node(nodeno INTEGER PRIMARY KEY, data BLOB)
+**   CREATE TABLE %_parent(nodeno INTEGER PRIMARY KEY, parentnode INTEGER)
+**   CREATE TABLE %_rowid(rowid INTEGER PRIMARY KEY, nodeno INTEGER, ...)
+**
+** The data for each node of the r-tree structure is stored in the %_node
+** table. For each node that is not the root node of the r-tree, there is
+** an entry in the %_parent table associating the node with its parent.
+** And for each row of data in the table, there is an entry in the %_rowid
+** table that maps from the entries rowid to the id of the node that it
+** is stored on.  If the r-tree contains auxiliary columns, those are stored
+** on the end of the %_rowid table.
+**
+** The root node of an r-tree always exists, even if the r-tree table is
+** empty. The nodeno of the root node is always 1. All other nodes in the
+** table must be the same size as the root node. The content of each node
+** is formatted as follows:
+**
+**   1. If the node is the root node (node 1), then the first 2 bytes
+**      of the node contain the tree depth as a big-endian integer.
+**      For non-root nodes, the first 2 bytes are left unused.
+**
+**   2. The next 2 bytes contain the number of entries currently
+**      stored in the node.
+**
+**   3. The remainder of the node contains the node entries. Each entry
+**      consists of a single 8-byte integer followed by an even number
+**      of 4-byte coordinates. For leaf nodes the integer is the rowid
+**      of a record. For internal nodes it is the node number of a
+**      child page.
+*/
+
+#if !defined(SQLITE_CORE) \
+  || (defined(SQLITE_ENABLE_RTREE) && !defined(SQLITE_OMIT_VIRTUALTABLE))
+
+#ifndef SQLITE_CORE
+/*   #include "sqlite3ext.h" */
+  SQLITE_EXTENSION_INIT1
+#else
+/*   #include "sqlite3.h" */
+#endif
+SQLITE_PRIVATE int sqlite3GetToken(const unsigned char*,int*); /* In the SQLite core */
+
+/*
+** If building separately, we will need some setup that is normally
+** found in sqliteInt.h
+*/
+#if !defined(SQLITE_AMALGAMATION)
+#include "sqlite3rtree.h"
+typedef sqlite3_int64 i64;
+typedef sqlite3_uint64 u64;
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+#if defined(NDEBUG) && defined(SQLITE_DEBUG)
+# undef NDEBUG
+#endif
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
+# define SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS 1
+#endif
+#if defined(SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS)
+# define ALWAYS(X)      (1)
+# define NEVER(X)       (0)
+#elif !defined(NDEBUG)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
+#else
+# define ALWAYS(X)      (X)
+# define NEVER(X)       (X)
+#endif
+#endif /* !defined(SQLITE_AMALGAMATION) */
+
+/* Macro to check for 4-byte alignment.  Only used inside of assert() */
+#ifdef SQLITE_DEBUG
+# define FOUR_BYTE_ALIGNED(X)  ((((char*)(X) - (char*)0) & 3)==0)
+#endif
+
+/* #include <string.h> */
+/* #include <stdio.h> */
+/* #include <assert.h> */
+/* #include <stdlib.h> */
+
+/*  The following macro is used to suppress compiler warnings.
+*/
+#ifndef UNUSED_PARAMETER
+# define UNUSED_PARAMETER(x) (void)(x)
+#endif
+
+typedef struct Rtree Rtree;
+typedef struct RtreeCursor RtreeCursor;
+typedef struct RtreeNode RtreeNode;
+typedef struct RtreeCell RtreeCell;
+typedef struct RtreeConstraint RtreeConstraint;
+typedef struct RtreeMatchArg RtreeMatchArg;
+typedef struct RtreeGeomCallback RtreeGeomCallback;
+typedef union RtreeCoord RtreeCoord;
+typedef struct RtreeSearchPoint RtreeSearchPoint;
+
+/* The rtree may have between 1 and RTREE_MAX_DIMENSIONS dimensions. */
+#define RTREE_MAX_DIMENSIONS 5
+
+/* Maximum number of auxiliary columns */
+#define RTREE_MAX_AUX_COLUMN 100
+
+/* Size of hash table Rtree.aHash. This hash table is not expected to
+** ever contain very many entries, so a fixed number of buckets is
+** used.
+*/
+#define HASHSIZE 97
+
+/* The xBestIndex method of this virtual table requires an estimate of
+** the number of rows in the virtual table to calculate the costs of
+** various strategies. If possible, this estimate is loaded from the
+** sqlite_stat1 table (with RTREE_MIN_ROWEST as a hard-coded minimum).
+** Otherwise, if no sqlite_stat1 entry is available, use
+** RTREE_DEFAULT_ROWEST.
+*/
+#define RTREE_DEFAULT_ROWEST 1048576
+#define RTREE_MIN_ROWEST         100
+
+/*
+** An rtree virtual-table object.
+*/
+struct Rtree {
+  sqlite3_vtab base;          /* Base class.  Must be first */
+  sqlite3 *db;                /* Host database connection */
+  int iNodeSize;              /* Size in bytes of each node in the node table */
+  u8 nDim;                    /* Number of dimensions */
+  u8 nDim2;                   /* Twice the number of dimensions */
+  u8 eCoordType;              /* RTREE_COORD_REAL32 or RTREE_COORD_INT32 */
+  u8 nBytesPerCell;           /* Bytes consumed per cell */
+  u8 inWrTrans;               /* True if inside write transaction */
+  u8 nAux;                    /* # of auxiliary columns in %_rowid */
+#ifdef SQLITE_ENABLE_GEOPOLY
+  u8 nAuxNotNull;             /* Number of initial not-null aux columns */
+#endif
+#ifdef SQLITE_DEBUG
+  u8 bCorrupt;                /* Shadow table corruption detected */
+#endif
+  int iDepth;                 /* Current depth of the r-tree structure */
+  char *zDb;                  /* Name of database containing r-tree table */
+  char *zName;                /* Name of r-tree table */
+  char *zNodeName;            /* Name of the %_node table */
+  u32 nBusy;                  /* Current number of users of this structure */
+  i64 nRowEst;                /* Estimated number of rows in this table */
+  u32 nCursor;                /* Number of open cursors */
+  u32 nNodeRef;               /* Number RtreeNodes with positive nRef */
+  char *zReadAuxSql;          /* SQL for statement to read aux data */
+
+  /* List of nodes removed during a CondenseTree operation. List is
+  ** linked together via the pointer normally used for hash chains -
+  ** RtreeNode.pNext. RtreeNode.iNode stores the depth of the sub-tree
+  ** headed by the node (leaf nodes have RtreeNode.iNode==0).
+  */
+  RtreeNode *pDeleted;
+
+  /* Blob I/O on xxx_node */
+  sqlite3_blob *pNodeBlob;
+
+  /* Statements to read/write/delete a record from xxx_node */
+  sqlite3_stmt *pWriteNode;
+  sqlite3_stmt *pDeleteNode;
+
+  /* Statements to read/write/delete a record from xxx_rowid */
+  sqlite3_stmt *pReadRowid;
+  sqlite3_stmt *pWriteRowid;
+  sqlite3_stmt *pDeleteRowid;
+
+  /* Statements to read/write/delete a record from xxx_parent */
+  sqlite3_stmt *pReadParent;
+  sqlite3_stmt *pWriteParent;
+  sqlite3_stmt *pDeleteParent;
+
+  /* Statement for writing to the "aux:" fields, if there are any */
+  sqlite3_stmt *pWriteAux;
+
+  RtreeNode *aHash[HASHSIZE]; /* Hash table of in-memory nodes. */
+};
+
+/* Possible values for Rtree.eCoordType: */
+#define RTREE_COORD_REAL32 0
+#define RTREE_COORD_INT32  1
+
+/*
+** If SQLITE_RTREE_INT_ONLY is defined, then this virtual table will
+** only deal with integer coordinates.  No floating point operations
+** will be done.
+*/
+#ifdef SQLITE_RTREE_INT_ONLY
+  typedef sqlite3_int64 RtreeDValue;       /* High accuracy coordinate */
+  typedef int RtreeValue;                  /* Low accuracy coordinate */
+# define RTREE_ZERO 0
+#else
+  typedef double RtreeDValue;              /* High accuracy coordinate */
+  typedef float RtreeValue;                /* Low accuracy coordinate */
+# define RTREE_ZERO 0.0
+#endif
+
+/*
+** Set the Rtree.bCorrupt flag
+*/
+#ifdef SQLITE_DEBUG
+# define RTREE_IS_CORRUPT(X) ((X)->bCorrupt = 1)
+#else
+# define RTREE_IS_CORRUPT(X)
+#endif
+
+/*
+** When doing a search of an r-tree, instances of the following structure
+** record intermediate results from the tree walk.
+**
+** The id is always a node-id.  For iLevel>=1 the id is the node-id of
+** the node that the RtreeSearchPoint represents.  When iLevel==0, however,
+** the id is of the parent node and the cell that RtreeSearchPoint
+** represents is the iCell-th entry in the parent node.
+*/
+struct RtreeSearchPoint {
+  RtreeDValue rScore;    /* The score for this node.  Smallest goes first. */
+  sqlite3_int64 id;      /* Node ID */
+  u8 iLevel;             /* 0=entries.  1=leaf node.  2+ for higher */
+  u8 eWithin;            /* PARTLY_WITHIN or FULLY_WITHIN */
+  u8 iCell;              /* Cell index within the node */
+};
+
+/*
+** The minimum number of cells allowed for a node is a third of the
+** maximum. In Gutman's notation:
+**
+**     m = M/3
+**
+** If an R*-tree "Reinsert" operation is required, the same number of
+** cells are removed from the overfull node and reinserted into the tree.
+*/
+#define RTREE_MINCELLS(p) ((((p)->iNodeSize-4)/(p)->nBytesPerCell)/3)
+#define RTREE_REINSERT(p) RTREE_MINCELLS(p)
+#define RTREE_MAXCELLS 51
+
+/*
+** The smallest possible node-size is (512-64)==448 bytes. And the largest
+** supported cell size is 48 bytes (8 byte rowid + ten 4 byte coordinates).
+** Therefore all non-root nodes must contain at least 3 entries. Since
+** 3^40 is greater than 2^64, an r-tree structure always has a depth of
+** 40 or less.
+*/
+#define RTREE_MAX_DEPTH 40
+
+
+/*
+** Number of entries in the cursor RtreeNode cache.  The first entry is
+** used to cache the RtreeNode for RtreeCursor.sPoint.  The remaining
+** entries cache the RtreeNode for the first elements of the priority queue.
+*/
+#define RTREE_CACHE_SZ  5
+
+/*
+** An rtree cursor object.
+*/
+struct RtreeCursor {
+  sqlite3_vtab_cursor base;         /* Base class.  Must be first */
+  u8 atEOF;                         /* True if at end of search */
+  u8 bPoint;                        /* True if sPoint is valid */
+  u8 bAuxValid;                     /* True if pReadAux is valid */
+  int iStrategy;                    /* Copy of idxNum search parameter */
+  int nConstraint;                  /* Number of entries in aConstraint */
+  RtreeConstraint *aConstraint;     /* Search constraints. */
+  int nPointAlloc;                  /* Number of slots allocated for aPoint[] */
+  int nPoint;                       /* Number of slots used in aPoint[] */
+  int mxLevel;                      /* iLevel value for root of the tree */
+  RtreeSearchPoint *aPoint;         /* Priority queue for search points */
+  sqlite3_stmt *pReadAux;           /* Statement to read aux-data */
+  RtreeSearchPoint sPoint;          /* Cached next search point */
+  RtreeNode *aNode[RTREE_CACHE_SZ]; /* Rtree node cache */
+  u32 anQueue[RTREE_MAX_DEPTH+1];   /* Number of queued entries by iLevel */
+};
+
+/* Return the Rtree of a RtreeCursor */
+#define RTREE_OF_CURSOR(X)   ((Rtree*)((X)->base.pVtab))
+
+/*
+** A coordinate can be either a floating point number or a integer.  All
+** coordinates within a single R-Tree are always of the same time.
+*/
+union RtreeCoord {
+  RtreeValue f;      /* Floating point value */
+  int i;             /* Integer value */
+  u32 u;             /* Unsigned for byte-order conversions */
+};
+
+/*
+** The argument is an RtreeCoord. Return the value stored within the RtreeCoord
+** formatted as a RtreeDValue (double or int64). This macro assumes that local
+** variable pRtree points to the Rtree structure associated with the
+** RtreeCoord.
+*/
+#ifdef SQLITE_RTREE_INT_ONLY
+# define DCOORD(coord) ((RtreeDValue)coord.i)
+#else
+# define DCOORD(coord) (                           \
+    (pRtree->eCoordType==RTREE_COORD_REAL32) ?      \
+      ((double)coord.f) :                           \
+      ((double)coord.i)                             \
+  )
+#endif
+
+/*
+** A search constraint.
+*/
+struct RtreeConstraint {
+  int iCoord;                     /* Index of constrained coordinate */
+  int op;                         /* Constraining operation */
+  union {
+    RtreeDValue rValue;             /* Constraint value. */
+    int (*xGeom)(sqlite3_rtree_geometry*,int,RtreeDValue*,int*);
+    int (*xQueryFunc)(sqlite3_rtree_query_info*);
+  } u;
+  sqlite3_rtree_query_info *pInfo;  /* xGeom and xQueryFunc argument */
+};
+
+/* Possible values for RtreeConstraint.op */
+#define RTREE_EQ    0x41  /* A */
+#define RTREE_LE    0x42  /* B */
+#define RTREE_LT    0x43  /* C */
+#define RTREE_GE    0x44  /* D */
+#define RTREE_GT    0x45  /* E */
+#define RTREE_MATCH 0x46  /* F: Old-style sqlite3_rtree_geometry_callback() */
+#define RTREE_QUERY 0x47  /* G: New-style sqlite3_rtree_query_callback() */
+
+/* Special operators available only on cursors.  Needs to be consecutive
+** with the normal values above, but must be less than RTREE_MATCH.  These
+** are used in the cursor for contraints such as x=NULL (RTREE_FALSE) or
+** x<'xyz' (RTREE_TRUE) */
+#define RTREE_TRUE  0x3f  /* ? */
+#define RTREE_FALSE 0x40  /* @ */
+
+/*
+** An rtree structure node.
+*/
+struct RtreeNode {
+  RtreeNode *pParent;         /* Parent node */
+  i64 iNode;                  /* The node number */
+  int nRef;                   /* Number of references to this node */
+  int isDirty;                /* True if the node needs to be written to disk */
+  u8 *zData;                  /* Content of the node, as should be on disk */
+  RtreeNode *pNext;           /* Next node in this hash collision chain */
+};
+
+/* Return the number of cells in a node  */
+#define NCELL(pNode) readInt16(&(pNode)->zData[2])
+
+/*
+** A single cell from a node, deserialized
+*/
+struct RtreeCell {
+  i64 iRowid;                                 /* Node or entry ID */
+  RtreeCoord aCoord[RTREE_MAX_DIMENSIONS*2];  /* Bounding box coordinates */
+};
+
+
+/*
+** This object becomes the sqlite3_user_data() for the SQL functions
+** that are created by sqlite3_rtree_geometry_callback() and
+** sqlite3_rtree_query_callback() and which appear on the right of MATCH
+** operators in order to constrain a search.
+**
+** xGeom and xQueryFunc are the callback functions.  Exactly one of
+** xGeom and xQueryFunc fields is non-NULL, depending on whether the
+** SQL function was created using sqlite3_rtree_geometry_callback() or
+** sqlite3_rtree_query_callback().
+**
+** This object is deleted automatically by the destructor mechanism in
+** sqlite3_create_function_v2().
+*/
+struct RtreeGeomCallback {
+  int (*xGeom)(sqlite3_rtree_geometry*, int, RtreeDValue*, int*);
+  int (*xQueryFunc)(sqlite3_rtree_query_info*);
+  void (*xDestructor)(void*);
+  void *pContext;
+};
+
+/*
+** An instance of this structure (in the form of a BLOB) is returned by
+** the SQL functions that sqlite3_rtree_geometry_callback() and
+** sqlite3_rtree_query_callback() create, and is read as the right-hand
+** operand to the MATCH operator of an R-Tree.
+*/
+struct RtreeMatchArg {
+  u32 iSize;                  /* Size of this object */
+  RtreeGeomCallback cb;       /* Info about the callback functions */
+  int nParam;                 /* Number of parameters to the SQL function */
+  sqlite3_value **apSqlParam; /* Original SQL parameter values */
+  RtreeDValue aParam[1];      /* Values for parameters to the SQL function */
+};
+
+#ifndef MAX
+# define MAX(x,y) ((x) < (y) ? (y) : (x))
+#endif
+#ifndef MIN
+# define MIN(x,y) ((x) > (y) ? (y) : (x))
+#endif
+
+/* What version of GCC is being used.  0 means GCC is not being used .
+** Note that the GCC_VERSION macro will also be set correctly when using
+** clang, since clang works hard to be gcc compatible.  So the gcc
+** optimizations will also work when compiling with clang.
+*/
+#ifndef GCC_VERSION
+#if defined(__GNUC__) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define GCC_VERSION (__GNUC__*1000000+__GNUC_MINOR__*1000+__GNUC_PATCHLEVEL__)
+#else
+# define GCC_VERSION 0
+#endif
+#endif
+
+/* The testcase() macro should already be defined in the amalgamation.  If
+** it is not, make it a no-op.
+*/
+#ifndef SQLITE_AMALGAMATION
+# if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_DEBUG)
+    unsigned int sqlite3RtreeTestcase = 0;
+#   define testcase(X)  if( X ){ sqlite3RtreeTestcase += __LINE__; }
+# else
+#   define testcase(X)
+# endif
+#endif
+
+/*
+** Make sure that the compiler intrinsics we desire are enabled when
+** compiling with an appropriate version of MSVC unless prevented by
+** the SQLITE_DISABLE_INTRINSIC define.
+*/
+#if !defined(SQLITE_DISABLE_INTRINSIC)
+#  if defined(_MSC_VER) && _MSC_VER>=1400
+#    if !defined(_WIN32_WCE)
+/* #      include <intrin.h> */
+#      pragma intrinsic(_byteswap_ulong)
+#      pragma intrinsic(_byteswap_uint64)
+#    else
+/* #      include <cmnintrin.h> */
+#    endif
+#  endif
+#endif
+
+/*
+** Macros to determine whether the machine is big or little endian,
+** and whether or not that determination is run-time or compile-time.
+**
+** For best performance, an attempt is made to guess at the byte-order
+** using C-preprocessor macros.  If that is unsuccessful, or if
+** -DSQLITE_RUNTIME_BYTEORDER=1 is set, then byte-order is determined
+** at run-time.
+*/
+#ifndef SQLITE_BYTEORDER /* Replicate changes at tag-20230904a */
+# if defined(__BYTE_ORDER__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
+#   define SQLITE_BYTEORDER 4321
+# elif defined(__BYTE_ORDER__) && __BYTE_ORDER__==__ORDER_LITTLE_ENDIAN__
+#   define SQLITE_BYTEORDER 1234
+# elif defined(__BIG_ENDIAN__) && __BIG_ENDIAN__==1
+#   define SQLITE_BYTEORDER 4321
+# elif defined(i386)    || defined(__i386__)      || defined(_M_IX86) ||    \
+     defined(__x86_64)  || defined(__x86_64__)    || defined(_M_X64)  ||    \
+     defined(_M_AMD64)  || defined(_M_ARM)        || defined(__x86)   ||    \
+     defined(__ARMEL__) || defined(__AARCH64EL__) || defined(_M_ARM64)
+#   define SQLITE_BYTEORDER 1234
+# elif defined(sparc)   || defined(__ARMEB__)     || defined(__AARCH64EB__)
+#   define SQLITE_BYTEORDER 4321
+# else
+#   define SQLITE_BYTEORDER 0
+# endif
+#endif
+
+
+/* What version of MSVC is being used.  0 means MSVC is not being used */
+#ifndef MSVC_VERSION
+#if defined(_MSC_VER) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define MSVC_VERSION _MSC_VER
+#else
+# define MSVC_VERSION 0
+#endif
+#endif
+
+/*
+** Functions to deserialize a 16 bit integer, 32 bit real number and
+** 64 bit integer. The deserialized value is returned.
+*/
+static int readInt16(u8 *p){
+  return (p[0]<<8) + p[1];
+}
+static void readCoord(u8 *p, RtreeCoord *pCoord){
+  assert( FOUR_BYTE_ALIGNED(p) );
+#if SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  pCoord->u = _byteswap_ulong(*(u32*)p);
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  pCoord->u = __builtin_bswap32(*(u32*)p);
+#elif SQLITE_BYTEORDER==4321
+  pCoord->u = *(u32*)p;
+#else
+  pCoord->u = (
+    (((u32)p[0]) << 24) +
+    (((u32)p[1]) << 16) +
+    (((u32)p[2]) <<  8) +
+    (((u32)p[3]) <<  0)
+  );
+#endif
+}
+static i64 readInt64(u8 *p){
+#if SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  u64 x;
+  memcpy(&x, p, 8);
+  return (i64)_byteswap_uint64(x);
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  u64 x;
+  memcpy(&x, p, 8);
+  return (i64)__builtin_bswap64(x);
+#elif SQLITE_BYTEORDER==4321
+  i64 x;
+  memcpy(&x, p, 8);
+  return x;
+#else
+  return (i64)(
+    (((u64)p[0]) << 56) +
+    (((u64)p[1]) << 48) +
+    (((u64)p[2]) << 40) +
+    (((u64)p[3]) << 32) +
+    (((u64)p[4]) << 24) +
+    (((u64)p[5]) << 16) +
+    (((u64)p[6]) <<  8) +
+    (((u64)p[7]) <<  0)
+  );
+#endif
+}
+
+/*
+** Functions to serialize a 16 bit integer, 32 bit real number and
+** 64 bit integer. The value returned is the number of bytes written
+** to the argument buffer (always 2, 4 and 8 respectively).
+*/
+static void writeInt16(u8 *p, int i){
+  p[0] = (i>> 8)&0xFF;
+  p[1] = (i>> 0)&0xFF;
+}
+static int writeCoord(u8 *p, RtreeCoord *pCoord){
+  u32 i;
+  assert( FOUR_BYTE_ALIGNED(p) );
+  assert( sizeof(RtreeCoord)==4 );
+  assert( sizeof(u32)==4 );
+#if SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  i = __builtin_bswap32(pCoord->u);
+  memcpy(p, &i, 4);
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  i = _byteswap_ulong(pCoord->u);
+  memcpy(p, &i, 4);
+#elif SQLITE_BYTEORDER==4321
+  i = pCoord->u;
+  memcpy(p, &i, 4);
+#else
+  i = pCoord->u;
+  p[0] = (i>>24)&0xFF;
+  p[1] = (i>>16)&0xFF;
+  p[2] = (i>> 8)&0xFF;
+  p[3] = (i>> 0)&0xFF;
+#endif
+  return 4;
+}
+static int writeInt64(u8 *p, i64 i){
+#if SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+  i = (i64)__builtin_bswap64((u64)i);
+  memcpy(p, &i, 8);
+#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+  i = (i64)_byteswap_uint64((u64)i);
+  memcpy(p, &i, 8);
+#elif SQLITE_BYTEORDER==4321
+  memcpy(p, &i, 8);
+#else
+  p[0] = (i>>56)&0xFF;
+  p[1] = (i>>48)&0xFF;
+  p[2] = (i>>40)&0xFF;
+  p[3] = (i>>32)&0xFF;
+  p[4] = (i>>24)&0xFF;
+  p[5] = (i>>16)&0xFF;
+  p[6] = (i>> 8)&0xFF;
+  p[7] = (i>> 0)&0xFF;
+#endif
+  return 8;
+}
+
+/*
+** Increment the reference count of node p.
+*/
+static void nodeReference(RtreeNode *p){
+  if( p ){
+    assert( p->nRef>0 );
+    p->nRef++;
+  }
+}
+
+/*
+** Clear the content of node p (set all bytes to 0x00).
+*/
+static void nodeZero(Rtree *pRtree, RtreeNode *p){
+  memset(&p->zData[2], 0, pRtree->iNodeSize-2);
+  p->isDirty = 1;
+}
+
+/*
+** Given a node number iNode, return the corresponding key to use
+** in the Rtree.aHash table.
+*/
+static unsigned int nodeHash(i64 iNode){
+  return ((unsigned)iNode) % HASHSIZE;
+}
+
+/*
+** Search the node hash table for node iNode. If found, return a pointer
+** to it. Otherwise, return 0.
+*/
+static RtreeNode *nodeHashLookup(Rtree *pRtree, i64 iNode){
+  RtreeNode *p;
+  for(p=pRtree->aHash[nodeHash(iNode)]; p && p->iNode!=iNode; p=p->pNext);
+  return p;
+}
+
+/*
+** Add node pNode to the node hash table.
+*/
+static void nodeHashInsert(Rtree *pRtree, RtreeNode *pNode){
+  int iHash;
+  assert( pNode->pNext==0 );
+  iHash = nodeHash(pNode->iNode);
+  pNode->pNext = pRtree->aHash[iHash];
+  pRtree->aHash[iHash] = pNode;
+}
+
+/*
+** Remove node pNode from the node hash table.
+*/
+static void nodeHashDelete(Rtree *pRtree, RtreeNode *pNode){
+  RtreeNode **pp;
+  if( pNode->iNode!=0 ){
+    pp = &pRtree->aHash[nodeHash(pNode->iNode)];
+    for( ; (*pp)!=pNode; pp = &(*pp)->pNext){ assert(*pp); }
+    *pp = pNode->pNext;
+    pNode->pNext = 0;
+  }
+}
+
+/*
+** Allocate and return new r-tree node. Initially, (RtreeNode.iNode==0),
+** indicating that node has not yet been assigned a node number. It is
+** assigned a node number when nodeWrite() is called to write the
+** node contents out to the database.
+*/
+static RtreeNode *nodeNew(Rtree *pRtree, RtreeNode *pParent){
+  RtreeNode *pNode;
+  pNode = (RtreeNode *)sqlite3_malloc64(sizeof(RtreeNode) + pRtree->iNodeSize);
+  if( pNode ){
+    memset(pNode, 0, sizeof(RtreeNode) + pRtree->iNodeSize);
+    pNode->zData = (u8 *)&pNode[1];
+    pNode->nRef = 1;
+    pRtree->nNodeRef++;
+    pNode->pParent = pParent;
+    pNode->isDirty = 1;
+    nodeReference(pParent);
+  }
+  return pNode;
+}
+
+/*
+** Clear the Rtree.pNodeBlob object
+*/
+static void nodeBlobReset(Rtree *pRtree){
+  sqlite3_blob *pBlob = pRtree->pNodeBlob;
+  pRtree->pNodeBlob = 0;
+  sqlite3_blob_close(pBlob);
+}
+
+/*
+** Obtain a reference to an r-tree node.
+*/
+static int nodeAcquire(
+  Rtree *pRtree,             /* R-tree structure */
+  i64 iNode,                 /* Node number to load */
+  RtreeNode *pParent,        /* Either the parent node or NULL */
+  RtreeNode **ppNode         /* OUT: Acquired node */
+){
+  int rc = SQLITE_OK;
+  RtreeNode *pNode = 0;
+
+  /* Check if the requested node is already in the hash table. If so,
+  ** increase its reference count and return it.
+  */
+  if( (pNode = nodeHashLookup(pRtree, iNode))!=0 ){
+    if( pParent && ALWAYS(pParent!=pNode->pParent) ){
+      RTREE_IS_CORRUPT(pRtree);
+      return SQLITE_CORRUPT_VTAB;
+    }
+    pNode->nRef++;
+    *ppNode = pNode;
+    return SQLITE_OK;
+  }
+
+  if( pRtree->pNodeBlob ){
+    sqlite3_blob *pBlob = pRtree->pNodeBlob;
+    pRtree->pNodeBlob = 0;
+    rc = sqlite3_blob_reopen(pBlob, iNode);
+    pRtree->pNodeBlob = pBlob;
+    if( rc ){
+      nodeBlobReset(pRtree);
+      if( rc==SQLITE_NOMEM ) return SQLITE_NOMEM;
+    }
+  }
+  if( pRtree->pNodeBlob==0 ){
+    rc = sqlite3_blob_open(pRtree->db, pRtree->zDb, pRtree->zNodeName,
+                           "data", iNode, 0,
+                           &pRtree->pNodeBlob);
+  }
+  if( rc ){
+    *ppNode = 0;
+    /* If unable to open an sqlite3_blob on the desired row, that can only
+    ** be because the shadow tables hold erroneous data. */
+    if( rc==SQLITE_ERROR ){
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+    }
+  }else if( pRtree->iNodeSize==sqlite3_blob_bytes(pRtree->pNodeBlob) ){
+    pNode = (RtreeNode *)sqlite3_malloc64(sizeof(RtreeNode)+pRtree->iNodeSize);
+    if( !pNode ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pNode->pParent = pParent;
+      pNode->zData = (u8 *)&pNode[1];
+      pNode->nRef = 1;
+      pRtree->nNodeRef++;
+      pNode->iNode = iNode;
+      pNode->isDirty = 0;
+      pNode->pNext = 0;
+      rc = sqlite3_blob_read(pRtree->pNodeBlob, pNode->zData,
+                             pRtree->iNodeSize, 0);
+    }
+  }
+
+  /* If the root node was just loaded, set pRtree->iDepth to the height
+  ** of the r-tree structure. A height of zero means all data is stored on
+  ** the root node. A height of one means the children of the root node
+  ** are the leaves, and so on. If the depth as specified on the root node
+  ** is greater than RTREE_MAX_DEPTH, the r-tree structure must be corrupt.
+  */
+  if( rc==SQLITE_OK && pNode && iNode==1 ){
+    pRtree->iDepth = readInt16(pNode->zData);
+    if( pRtree->iDepth>RTREE_MAX_DEPTH ){
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+    }
+  }
+
+  /* If no error has occurred so far, check if the "number of entries"
+  ** field on the node is too large. If so, set the return code to
+  ** SQLITE_CORRUPT_VTAB.
+  */
+  if( pNode && rc==SQLITE_OK ){
+    if( NCELL(pNode)>((pRtree->iNodeSize-4)/pRtree->nBytesPerCell) ){
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( pNode!=0 ){
+      nodeReference(pParent);
+      nodeHashInsert(pRtree, pNode);
+    }else{
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+    }
+    *ppNode = pNode;
+  }else{
+    nodeBlobReset(pRtree);
+    if( pNode ){
+      pRtree->nNodeRef--;
+      sqlite3_free(pNode);
+    }
+    *ppNode = 0;
+  }
+
+  return rc;
+}
+
+/*
+** Overwrite cell iCell of node pNode with the contents of pCell.
+*/
+static void nodeOverwriteCell(
+  Rtree *pRtree,             /* The overall R-Tree */
+  RtreeNode *pNode,          /* The node into which the cell is to be written */
+  RtreeCell *pCell,          /* The cell to write */
+  int iCell                  /* Index into pNode into which pCell is written */
+){
+  int ii;
+  u8 *p = &pNode->zData[4 + pRtree->nBytesPerCell*iCell];
+  p += writeInt64(p, pCell->iRowid);
+  for(ii=0; ii<pRtree->nDim2; ii++){
+    p += writeCoord(p, &pCell->aCoord[ii]);
+  }
+  pNode->isDirty = 1;
+}
+
+/*
+** Remove the cell with index iCell from node pNode.
+*/
+static void nodeDeleteCell(Rtree *pRtree, RtreeNode *pNode, int iCell){
+  u8 *pDst = &pNode->zData[4 + pRtree->nBytesPerCell*iCell];
+  u8 *pSrc = &pDst[pRtree->nBytesPerCell];
+  int nByte = (NCELL(pNode) - iCell - 1) * pRtree->nBytesPerCell;
+  memmove(pDst, pSrc, nByte);
+  writeInt16(&pNode->zData[2], NCELL(pNode)-1);
+  pNode->isDirty = 1;
+}
+
+/*
+** Insert the contents of cell pCell into node pNode. If the insert
+** is successful, return SQLITE_OK.
+**
+** If there is not enough free space in pNode, return SQLITE_FULL.
+*/
+static int nodeInsertCell(
+  Rtree *pRtree,                /* The overall R-Tree */
+  RtreeNode *pNode,             /* Write new cell into this node */
+  RtreeCell *pCell              /* The cell to be inserted */
+){
+  int nCell;                    /* Current number of cells in pNode */
+  int nMaxCell;                 /* Maximum number of cells for pNode */
+
+  nMaxCell = (pRtree->iNodeSize-4)/pRtree->nBytesPerCell;
+  nCell = NCELL(pNode);
+
+  assert( nCell<=nMaxCell );
+  if( nCell<nMaxCell ){
+    nodeOverwriteCell(pRtree, pNode, pCell, nCell);
+    writeInt16(&pNode->zData[2], nCell+1);
+    pNode->isDirty = 1;
+  }
+
+  return (nCell==nMaxCell);
+}
+
+/*
+** If the node is dirty, write it out to the database.
+*/
+static int nodeWrite(Rtree *pRtree, RtreeNode *pNode){
+  int rc = SQLITE_OK;
+  if( pNode->isDirty ){
+    sqlite3_stmt *p = pRtree->pWriteNode;
+    if( pNode->iNode ){
+      sqlite3_bind_int64(p, 1, pNode->iNode);
+    }else{
+      sqlite3_bind_null(p, 1);
+    }
+    sqlite3_bind_blob(p, 2, pNode->zData, pRtree->iNodeSize, SQLITE_STATIC);
+    sqlite3_step(p);
+    pNode->isDirty = 0;
+    rc = sqlite3_reset(p);
+    sqlite3_bind_null(p, 2);
+    if( pNode->iNode==0 && rc==SQLITE_OK ){
+      pNode->iNode = sqlite3_last_insert_rowid(pRtree->db);
+      nodeHashInsert(pRtree, pNode);
+    }
+  }
+  return rc;
+}
+
+/*
+** Release a reference to a node. If the node is dirty and the reference
+** count drops to zero, the node data is written to the database.
+*/
+static int nodeRelease(Rtree *pRtree, RtreeNode *pNode){
+  int rc = SQLITE_OK;
+  if( pNode ){
+    assert( pNode->nRef>0 );
+    assert( pRtree->nNodeRef>0 );
+    pNode->nRef--;
+    if( pNode->nRef==0 ){
+      pRtree->nNodeRef--;
+      if( pNode->iNode==1 ){
+        pRtree->iDepth = -1;
+      }
+      if( pNode->pParent ){
+        rc = nodeRelease(pRtree, pNode->pParent);
+      }
+      if( rc==SQLITE_OK ){
+        rc = nodeWrite(pRtree, pNode);
+      }
+      nodeHashDelete(pRtree, pNode);
+      sqlite3_free(pNode);
+    }
+  }
+  return rc;
+}
+
+/*
+** Return the 64-bit integer value associated with cell iCell of
+** node pNode. If pNode is a leaf node, this is a rowid. If it is
+** an internal node, then the 64-bit integer is a child page number.
+*/
+static i64 nodeGetRowid(
+  Rtree *pRtree,       /* The overall R-Tree */
+  RtreeNode *pNode,    /* The node from which to extract the ID */
+  int iCell            /* The cell index from which to extract the ID */
+){
+  assert( iCell<NCELL(pNode) );
+  return readInt64(&pNode->zData[4 + pRtree->nBytesPerCell*iCell]);
+}
+
+/*
+** Return coordinate iCoord from cell iCell in node pNode.
+*/
+static void nodeGetCoord(
+  Rtree *pRtree,               /* The overall R-Tree */
+  RtreeNode *pNode,            /* The node from which to extract a coordinate */
+  int iCell,                   /* The index of the cell within the node */
+  int iCoord,                  /* Which coordinate to extract */
+  RtreeCoord *pCoord           /* OUT: Space to write result to */
+){
+  assert( iCell<NCELL(pNode) );
+  readCoord(&pNode->zData[12 + pRtree->nBytesPerCell*iCell + 4*iCoord], pCoord);
+}
+
+/*
+** Deserialize cell iCell of node pNode. Populate the structure pointed
+** to by pCell with the results.
+*/
+static void nodeGetCell(
+  Rtree *pRtree,               /* The overall R-Tree */
+  RtreeNode *pNode,            /* The node containing the cell to be read */
+  int iCell,                   /* Index of the cell within the node */
+  RtreeCell *pCell             /* OUT: Write the cell contents here */
+){
+  u8 *pData;
+  RtreeCoord *pCoord;
+  int ii = 0;
+  pCell->iRowid = nodeGetRowid(pRtree, pNode, iCell);
+  pData = pNode->zData + (12 + pRtree->nBytesPerCell*iCell);
+  pCoord = pCell->aCoord;
+  do{
+    readCoord(pData, &pCoord[ii]);
+    readCoord(pData+4, &pCoord[ii+1]);
+    pData += 8;
+    ii += 2;
+  }while( ii<pRtree->nDim2 );
+}
+
+
+/* Forward declaration for the function that does the work of
+** the virtual table module xCreate() and xConnect() methods.
+*/
+static int rtreeInit(
+  sqlite3 *, void *, int, const char *const*, sqlite3_vtab **, char **, int
+);
+
+/*
+** Rtree virtual table module xCreate method.
+*/
+static int rtreeCreate(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  return rtreeInit(db, pAux, argc, argv, ppVtab, pzErr, 1);
+}
+
+/*
+** Rtree virtual table module xConnect method.
+*/
+static int rtreeConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  return rtreeInit(db, pAux, argc, argv, ppVtab, pzErr, 0);
+}
+
+/*
+** Increment the r-tree reference count.
+*/
+static void rtreeReference(Rtree *pRtree){
+  pRtree->nBusy++;
+}
+
+/*
+** Decrement the r-tree reference count. When the reference count reaches
+** zero the structure is deleted.
+*/
+static void rtreeRelease(Rtree *pRtree){
+  pRtree->nBusy--;
+  if( pRtree->nBusy==0 ){
+    pRtree->inWrTrans = 0;
+    assert( pRtree->nCursor==0 );
+    nodeBlobReset(pRtree);
+    assert( pRtree->nNodeRef==0 || pRtree->bCorrupt );
+    sqlite3_finalize(pRtree->pWriteNode);
+    sqlite3_finalize(pRtree->pDeleteNode);
+    sqlite3_finalize(pRtree->pReadRowid);
+    sqlite3_finalize(pRtree->pWriteRowid);
+    sqlite3_finalize(pRtree->pDeleteRowid);
+    sqlite3_finalize(pRtree->pReadParent);
+    sqlite3_finalize(pRtree->pWriteParent);
+    sqlite3_finalize(pRtree->pDeleteParent);
+    sqlite3_finalize(pRtree->pWriteAux);
+    sqlite3_free(pRtree->zReadAuxSql);
+    sqlite3_free(pRtree);
+  }
+}
+
+/*
+** Rtree virtual table module xDisconnect method.
+*/
+static int rtreeDisconnect(sqlite3_vtab *pVtab){
+  rtreeRelease((Rtree *)pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** Rtree virtual table module xDestroy method.
+*/
+static int rtreeDestroy(sqlite3_vtab *pVtab){
+  Rtree *pRtree = (Rtree *)pVtab;
+  int rc;
+  char *zCreate = sqlite3_mprintf(
+    "DROP TABLE '%q'.'%q_node';"
+    "DROP TABLE '%q'.'%q_rowid';"
+    "DROP TABLE '%q'.'%q_parent';",
+    pRtree->zDb, pRtree->zName,
+    pRtree->zDb, pRtree->zName,
+    pRtree->zDb, pRtree->zName
+  );
+  if( !zCreate ){
+    rc = SQLITE_NOMEM;
+  }else{
+    nodeBlobReset(pRtree);
+    rc = sqlite3_exec(pRtree->db, zCreate, 0, 0, 0);
+    sqlite3_free(zCreate);
+  }
+  if( rc==SQLITE_OK ){
+    rtreeRelease(pRtree);
+  }
+
+  return rc;
+}
+
+/*
+** Rtree virtual table module xOpen method.
+*/
+static int rtreeOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+  int rc = SQLITE_NOMEM;
+  Rtree *pRtree = (Rtree *)pVTab;
+  RtreeCursor *pCsr;
+
+  pCsr = (RtreeCursor *)sqlite3_malloc64(sizeof(RtreeCursor));
+  if( pCsr ){
+    memset(pCsr, 0, sizeof(RtreeCursor));
+    pCsr->base.pVtab = pVTab;
+    rc = SQLITE_OK;
+    pRtree->nCursor++;
+  }
+  *ppCursor = (sqlite3_vtab_cursor *)pCsr;
+
+  return rc;
+}
+
+
+/*
+** Reset a cursor back to its initial state.
+*/
+static void resetCursor(RtreeCursor *pCsr){
+  Rtree *pRtree = (Rtree *)(pCsr->base.pVtab);
+  int ii;
+  sqlite3_stmt *pStmt;
+  if( pCsr->aConstraint ){
+    int i;                        /* Used to iterate through constraint array */
+    for(i=0; i<pCsr->nConstraint; i++){
+      sqlite3_rtree_query_info *pInfo = pCsr->aConstraint[i].pInfo;
+      if( pInfo ){
+        if( pInfo->xDelUser ) pInfo->xDelUser(pInfo->pUser);
+        sqlite3_free(pInfo);
+      }
+    }
+    sqlite3_free(pCsr->aConstraint);
+    pCsr->aConstraint = 0;
+  }
+  for(ii=0; ii<RTREE_CACHE_SZ; ii++) nodeRelease(pRtree, pCsr->aNode[ii]);
+  sqlite3_free(pCsr->aPoint);
+  pStmt = pCsr->pReadAux;
+  memset(pCsr, 0, sizeof(RtreeCursor));
+  pCsr->base.pVtab = (sqlite3_vtab*)pRtree;
+  pCsr->pReadAux = pStmt;
+
+}
+
+/*
+** Rtree virtual table module xClose method.
+*/
+static int rtreeClose(sqlite3_vtab_cursor *cur){
+  Rtree *pRtree = (Rtree *)(cur->pVtab);
+  RtreeCursor *pCsr = (RtreeCursor *)cur;
+  assert( pRtree->nCursor>0 );
+  resetCursor(pCsr);
+  sqlite3_finalize(pCsr->pReadAux);
+  sqlite3_free(pCsr);
+  pRtree->nCursor--;
+  if( pRtree->nCursor==0 && pRtree->inWrTrans==0 ){
+    nodeBlobReset(pRtree);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Rtree virtual table module xEof method.
+**
+** Return non-zero if the cursor does not currently point to a valid
+** record (i.e if the scan has finished), or zero otherwise.
+*/
+static int rtreeEof(sqlite3_vtab_cursor *cur){
+  RtreeCursor *pCsr = (RtreeCursor *)cur;
+  return pCsr->atEOF;
+}
+
+/*
+** Convert raw bits from the on-disk RTree record into a coordinate value.
+** The on-disk format is big-endian and needs to be converted for little-
+** endian platforms.  The on-disk record stores integer coordinates if
+** eInt is true and it stores 32-bit floating point records if eInt is
+** false.  a[] is the four bytes of the on-disk record to be decoded.
+** Store the results in "r".
+**
+** There are five versions of this macro.  The last one is generic.  The
+** other four are various architectures-specific optimizations.
+*/
+#if SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    c.u = _byteswap_ulong(*(u32*)a);                            \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    c.u = __builtin_bswap32(*(u32*)a);                          \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#elif SQLITE_BYTEORDER==1234
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    memcpy(&c.u,a,4);                                           \
+    c.u = ((c.u>>24)&0xff)|((c.u>>8)&0xff00)|                   \
+          ((c.u&0xff)<<24)|((c.u&0xff00)<<8);                   \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#elif SQLITE_BYTEORDER==4321
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    memcpy(&c.u,a,4);                                           \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#else
+#define RTREE_DECODE_COORD(eInt, a, r) {                        \
+    RtreeCoord c;    /* Coordinate decoded */                   \
+    c.u = ((u32)a[0]<<24) + ((u32)a[1]<<16)                     \
+           +((u32)a[2]<<8) + a[3];                              \
+    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
+}
+#endif
+
+/*
+** Check the RTree node or entry given by pCellData and p against the MATCH
+** constraint pConstraint.
+*/
+static int rtreeCallbackConstraint(
+  RtreeConstraint *pConstraint,  /* The constraint to test */
+  int eInt,                      /* True if RTree holding integer coordinates */
+  u8 *pCellData,                 /* Raw cell content */
+  RtreeSearchPoint *pSearch,     /* Container of this cell */
+  sqlite3_rtree_dbl *prScore,    /* OUT: score for the cell */
+  int *peWithin                  /* OUT: visibility of the cell */
+){
+  sqlite3_rtree_query_info *pInfo = pConstraint->pInfo; /* Callback info */
+  int nCoord = pInfo->nCoord;                           /* No. of coordinates */
+  int rc;                                             /* Callback return code */
+  RtreeCoord c;                                       /* Translator union */
+  sqlite3_rtree_dbl aCoord[RTREE_MAX_DIMENSIONS*2];   /* Decoded coordinates */
+
+  assert( pConstraint->op==RTREE_MATCH || pConstraint->op==RTREE_QUERY );
+  assert( nCoord==2 || nCoord==4 || nCoord==6 || nCoord==8 || nCoord==10 );
+
+  if( pConstraint->op==RTREE_QUERY && pSearch->iLevel==1 ){
+    pInfo->iRowid = readInt64(pCellData);
+  }
+  pCellData += 8;
+#ifndef SQLITE_RTREE_INT_ONLY
+  if( eInt==0 ){
+    switch( nCoord ){
+      case 10:  readCoord(pCellData+36, &c); aCoord[9] = c.f;
+                readCoord(pCellData+32, &c); aCoord[8] = c.f;
+      case 8:   readCoord(pCellData+28, &c); aCoord[7] = c.f;
+                readCoord(pCellData+24, &c); aCoord[6] = c.f;
+      case 6:   readCoord(pCellData+20, &c); aCoord[5] = c.f;
+                readCoord(pCellData+16, &c); aCoord[4] = c.f;
+      case 4:   readCoord(pCellData+12, &c); aCoord[3] = c.f;
+                readCoord(pCellData+8,  &c); aCoord[2] = c.f;
+      default:  readCoord(pCellData+4,  &c); aCoord[1] = c.f;
+                readCoord(pCellData,    &c); aCoord[0] = c.f;
+    }
+  }else
+#endif
+  {
+    switch( nCoord ){
+      case 10:  readCoord(pCellData+36, &c); aCoord[9] = c.i;
+                readCoord(pCellData+32, &c); aCoord[8] = c.i;
+      case 8:   readCoord(pCellData+28, &c); aCoord[7] = c.i;
+                readCoord(pCellData+24, &c); aCoord[6] = c.i;
+      case 6:   readCoord(pCellData+20, &c); aCoord[5] = c.i;
+                readCoord(pCellData+16, &c); aCoord[4] = c.i;
+      case 4:   readCoord(pCellData+12, &c); aCoord[3] = c.i;
+                readCoord(pCellData+8,  &c); aCoord[2] = c.i;
+      default:  readCoord(pCellData+4,  &c); aCoord[1] = c.i;
+                readCoord(pCellData,    &c); aCoord[0] = c.i;
+    }
+  }
+  if( pConstraint->op==RTREE_MATCH ){
+    int eWithin = 0;
+    rc = pConstraint->u.xGeom((sqlite3_rtree_geometry*)pInfo,
+                              nCoord, aCoord, &eWithin);
+    if( eWithin==0 ) *peWithin = NOT_WITHIN;
+    *prScore = RTREE_ZERO;
+  }else{
+    pInfo->aCoord = aCoord;
+    pInfo->iLevel = pSearch->iLevel - 1;
+    pInfo->rScore = pInfo->rParentScore = pSearch->rScore;
+    pInfo->eWithin = pInfo->eParentWithin = pSearch->eWithin;
+    rc = pConstraint->u.xQueryFunc(pInfo);
+    if( pInfo->eWithin<*peWithin ) *peWithin = pInfo->eWithin;
+    if( pInfo->rScore<*prScore || *prScore<RTREE_ZERO ){
+      *prScore = pInfo->rScore;
+    }
+  }
+  return rc;
+}
+
+/*
+** Check the internal RTree node given by pCellData against constraint p.
+** If this constraint cannot be satisfied by any child within the node,
+** set *peWithin to NOT_WITHIN.
+*/
+static void rtreeNonleafConstraint(
+  RtreeConstraint *p,        /* The constraint to test */
+  int eInt,                  /* True if RTree holds integer coordinates */
+  u8 *pCellData,             /* Raw cell content as appears on disk */
+  int *peWithin              /* Adjust downward, as appropriate */
+){
+  sqlite3_rtree_dbl val;     /* Coordinate value convert to a double */
+
+  /* p->iCoord might point to either a lower or upper bound coordinate
+  ** in a coordinate pair.  But make pCellData point to the lower bound.
+  */
+  pCellData += 8 + 4*(p->iCoord&0xfe);
+
+  assert(p->op==RTREE_LE || p->op==RTREE_LT || p->op==RTREE_GE
+      || p->op==RTREE_GT || p->op==RTREE_EQ || p->op==RTREE_TRUE
+      || p->op==RTREE_FALSE );
+  assert( FOUR_BYTE_ALIGNED(pCellData) );
+  switch( p->op ){
+    case RTREE_TRUE:  return;   /* Always satisfied */
+    case RTREE_FALSE: break;    /* Never satisfied */
+    case RTREE_EQ:
+      RTREE_DECODE_COORD(eInt, pCellData, val);
+      /* val now holds the lower bound of the coordinate pair */
+      if( p->u.rValue>=val ){
+        pCellData += 4;
+        RTREE_DECODE_COORD(eInt, pCellData, val);
+        /* val now holds the upper bound of the coordinate pair */
+        if( p->u.rValue<=val ) return;
+      }
+      break;
+    case RTREE_LE:
+    case RTREE_LT:
+      RTREE_DECODE_COORD(eInt, pCellData, val);
+      /* val now holds the lower bound of the coordinate pair */
+      if( p->u.rValue>=val ) return;
+      break;
+
+    default:
+      pCellData += 4;
+      RTREE_DECODE_COORD(eInt, pCellData, val);
+      /* val now holds the upper bound of the coordinate pair */
+      if( p->u.rValue<=val ) return;
+      break;
+  }
+  *peWithin = NOT_WITHIN;
+}
+
+/*
+** Check the leaf RTree cell given by pCellData against constraint p.
+** If this constraint is not satisfied, set *peWithin to NOT_WITHIN.
+** If the constraint is satisfied, leave *peWithin unchanged.
+**
+** The constraint is of the form:  xN op $val
+**
+** The op is given by p->op.  The xN is p->iCoord-th coordinate in
+** pCellData.  $val is given by p->u.rValue.
+*/
+static void rtreeLeafConstraint(
+  RtreeConstraint *p,        /* The constraint to test */
+  int eInt,                  /* True if RTree holds integer coordinates */
+  u8 *pCellData,             /* Raw cell content as appears on disk */
+  int *peWithin              /* Adjust downward, as appropriate */
+){
+  RtreeDValue xN;      /* Coordinate value converted to a double */
+
+  assert(p->op==RTREE_LE || p->op==RTREE_LT || p->op==RTREE_GE
+      || p->op==RTREE_GT || p->op==RTREE_EQ || p->op==RTREE_TRUE
+      || p->op==RTREE_FALSE );
+  pCellData += 8 + p->iCoord*4;
+  assert( FOUR_BYTE_ALIGNED(pCellData) );
+  RTREE_DECODE_COORD(eInt, pCellData, xN);
+  switch( p->op ){
+    case RTREE_TRUE:  return;   /* Always satisfied */
+    case RTREE_FALSE: break;    /* Never satisfied */
+    case RTREE_LE:    if( xN <= p->u.rValue ) return;  break;
+    case RTREE_LT:    if( xN <  p->u.rValue ) return;  break;
+    case RTREE_GE:    if( xN >= p->u.rValue ) return;  break;
+    case RTREE_GT:    if( xN >  p->u.rValue ) return;  break;
+    default:          if( xN == p->u.rValue ) return;  break;
+  }
+  *peWithin = NOT_WITHIN;
+}
+
+/*
+** One of the cells in node pNode is guaranteed to have a 64-bit
+** integer value equal to iRowid. Return the index of this cell.
+*/
+static int nodeRowidIndex(
+  Rtree *pRtree,
+  RtreeNode *pNode,
+  i64 iRowid,
+  int *piIndex
+){
+  int ii;
+  int nCell = NCELL(pNode);
+  assert( nCell<200 );
+  for(ii=0; ii<nCell; ii++){
+    if( nodeGetRowid(pRtree, pNode, ii)==iRowid ){
+      *piIndex = ii;
+      return SQLITE_OK;
+    }
+  }
+  RTREE_IS_CORRUPT(pRtree);
+  return SQLITE_CORRUPT_VTAB;
+}
+
+/*
+** Return the index of the cell containing a pointer to node pNode
+** in its parent. If pNode is the root node, return -1.
+*/
+static int nodeParentIndex(Rtree *pRtree, RtreeNode *pNode, int *piIndex){
+  RtreeNode *pParent = pNode->pParent;
+  if( ALWAYS(pParent) ){
+    return nodeRowidIndex(pRtree, pParent, pNode->iNode, piIndex);
+  }else{
+    *piIndex = -1;
+    return SQLITE_OK;
+  }
+}
+
+/*
+** Compare two search points.  Return negative, zero, or positive if the first
+** is less than, equal to, or greater than the second.
+**
+** The rScore is the primary key.  Smaller rScore values come first.
+** If the rScore is a tie, then use iLevel as the tie breaker with smaller
+** iLevel values coming first.  In this way, if rScore is the same for all
+** SearchPoints, then iLevel becomes the deciding factor and the result
+** is a depth-first search, which is the desired default behavior.
+*/
+static int rtreeSearchPointCompare(
+  const RtreeSearchPoint *pA,
+  const RtreeSearchPoint *pB
+){
+  if( pA->rScore<pB->rScore ) return -1;
+  if( pA->rScore>pB->rScore ) return +1;
+  if( pA->iLevel<pB->iLevel ) return -1;
+  if( pA->iLevel>pB->iLevel ) return +1;
+  return 0;
+}
+
+/*
+** Interchange two search points in a cursor.
+*/
+static void rtreeSearchPointSwap(RtreeCursor *p, int i, int j){
+  RtreeSearchPoint t = p->aPoint[i];
+  assert( i<j );
+  p->aPoint[i] = p->aPoint[j];
+  p->aPoint[j] = t;
+  i++; j++;
+  if( i<RTREE_CACHE_SZ ){
+    if( j>=RTREE_CACHE_SZ ){
+      nodeRelease(RTREE_OF_CURSOR(p), p->aNode[i]);
+      p->aNode[i] = 0;
+    }else{
+      RtreeNode *pTemp = p->aNode[i];
+      p->aNode[i] = p->aNode[j];
+      p->aNode[j] = pTemp;
+    }
+  }
+}
+
+/*
+** Return the search point with the lowest current score.
+*/
+static RtreeSearchPoint *rtreeSearchPointFirst(RtreeCursor *pCur){
+  return pCur->bPoint ? &pCur->sPoint : pCur->nPoint ? pCur->aPoint : 0;
+}
+
+/*
+** Get the RtreeNode for the search point with the lowest score.
+*/
+static RtreeNode *rtreeNodeOfFirstSearchPoint(RtreeCursor *pCur, int *pRC){
+  sqlite3_int64 id;
+  int ii = 1 - pCur->bPoint;
+  assert( ii==0 || ii==1 );
+  assert( pCur->bPoint || pCur->nPoint );
+  if( pCur->aNode[ii]==0 ){
+    assert( pRC!=0 );
+    id = ii ? pCur->aPoint[0].id : pCur->sPoint.id;
+    *pRC = nodeAcquire(RTREE_OF_CURSOR(pCur), id, 0, &pCur->aNode[ii]);
+  }
+  return pCur->aNode[ii];
+}
+
+/*
+** Push a new element onto the priority queue
+*/
+static RtreeSearchPoint *rtreeEnqueue(
+  RtreeCursor *pCur,    /* The cursor */
+  RtreeDValue rScore,   /* Score for the new search point */
+  u8 iLevel             /* Level for the new search point */
+){
+  int i, j;
+  RtreeSearchPoint *pNew;
+  if( pCur->nPoint>=pCur->nPointAlloc ){
+    int nNew = pCur->nPointAlloc*2 + 8;
+    pNew = sqlite3_realloc64(pCur->aPoint, nNew*sizeof(pCur->aPoint[0]));
+    if( pNew==0 ) return 0;
+    pCur->aPoint = pNew;
+    pCur->nPointAlloc = nNew;
+  }
+  i = pCur->nPoint++;
+  pNew = pCur->aPoint + i;
+  pNew->rScore = rScore;
+  pNew->iLevel = iLevel;
+  assert( iLevel<=RTREE_MAX_DEPTH );
+  while( i>0 ){
+    RtreeSearchPoint *pParent;
+    j = (i-1)/2;
+    pParent = pCur->aPoint + j;
+    if( rtreeSearchPointCompare(pNew, pParent)>=0 ) break;
+    rtreeSearchPointSwap(pCur, j, i);
+    i = j;
+    pNew = pParent;
+  }
+  return pNew;
+}
+
+/*
+** Allocate a new RtreeSearchPoint and return a pointer to it.  Return
+** NULL if malloc fails.
+*/
+static RtreeSearchPoint *rtreeSearchPointNew(
+  RtreeCursor *pCur,    /* The cursor */
+  RtreeDValue rScore,   /* Score for the new search point */
+  u8 iLevel             /* Level for the new search point */
+){
+  RtreeSearchPoint *pNew, *pFirst;
+  pFirst = rtreeSearchPointFirst(pCur);
+  pCur->anQueue[iLevel]++;
+  if( pFirst==0
+   || pFirst->rScore>rScore
+   || (pFirst->rScore==rScore && pFirst->iLevel>iLevel)
+  ){
+    if( pCur->bPoint ){
+      int ii;
+      pNew = rtreeEnqueue(pCur, rScore, iLevel);
+      if( pNew==0 ) return 0;
+      ii = (int)(pNew - pCur->aPoint) + 1;
+      assert( ii==1 );
+      if( ALWAYS(ii<RTREE_CACHE_SZ) ){
+        assert( pCur->aNode[ii]==0 );
+        pCur->aNode[ii] = pCur->aNode[0];
+      }else{
+        nodeRelease(RTREE_OF_CURSOR(pCur), pCur->aNode[0]);
+      }
+      pCur->aNode[0] = 0;
+      *pNew = pCur->sPoint;
+    }
+    pCur->sPoint.rScore = rScore;
+    pCur->sPoint.iLevel = iLevel;
+    pCur->bPoint = 1;
+    return &pCur->sPoint;
+  }else{
+    return rtreeEnqueue(pCur, rScore, iLevel);
+  }
+}
+
+#if 0
+/* Tracing routines for the RtreeSearchPoint queue */
+static void tracePoint(RtreeSearchPoint *p, int idx, RtreeCursor *pCur){
+  if( idx<0 ){ printf(" s"); }else{ printf("%2d", idx); }
+  printf(" %d.%05lld.%02d %g %d",
+    p->iLevel, p->id, p->iCell, p->rScore, p->eWithin
+  );
+  idx++;
+  if( idx<RTREE_CACHE_SZ ){
+    printf(" %p\n", pCur->aNode[idx]);
+  }else{
+    printf("\n");
+  }
+}
+static void traceQueue(RtreeCursor *pCur, const char *zPrefix){
+  int ii;
+  printf("=== %9s ", zPrefix);
+  if( pCur->bPoint ){
+    tracePoint(&pCur->sPoint, -1, pCur);
+  }
+  for(ii=0; ii<pCur->nPoint; ii++){
+    if( ii>0 || pCur->bPoint ) printf("              ");
+    tracePoint(&pCur->aPoint[ii], ii, pCur);
+  }
+}
+# define RTREE_QUEUE_TRACE(A,B) traceQueue(A,B)
+#else
+# define RTREE_QUEUE_TRACE(A,B)   /* no-op */
+#endif
+
+/* Remove the search point with the lowest current score.
+*/
+static void rtreeSearchPointPop(RtreeCursor *p){
+  int i, j, k, n;
+  i = 1 - p->bPoint;
+  assert( i==0 || i==1 );
+  if( p->aNode[i] ){
+    nodeRelease(RTREE_OF_CURSOR(p), p->aNode[i]);
+    p->aNode[i] = 0;
+  }
+  if( p->bPoint ){
+    p->anQueue[p->sPoint.iLevel]--;
+    p->bPoint = 0;
+  }else if( ALWAYS(p->nPoint) ){
+    p->anQueue[p->aPoint[0].iLevel]--;
+    n = --p->nPoint;
+    p->aPoint[0] = p->aPoint[n];
+    if( n<RTREE_CACHE_SZ-1 ){
+      p->aNode[1] = p->aNode[n+1];
+      p->aNode[n+1] = 0;
+    }
+    i = 0;
+    while( (j = i*2+1)<n ){
+      k = j+1;
+      if( k<n && rtreeSearchPointCompare(&p->aPoint[k], &p->aPoint[j])<0 ){
+        if( rtreeSearchPointCompare(&p->aPoint[k], &p->aPoint[i])<0 ){
+          rtreeSearchPointSwap(p, i, k);
+          i = k;
+        }else{
+          break;
+        }
+      }else{
+        if( rtreeSearchPointCompare(&p->aPoint[j], &p->aPoint[i])<0 ){
+          rtreeSearchPointSwap(p, i, j);
+          i = j;
+        }else{
+          break;
+        }
+      }
+    }
+  }
+}
+
+
+/*
+** Continue the search on cursor pCur until the front of the queue
+** contains an entry suitable for returning as a result-set row,
+** or until the RtreeSearchPoint queue is empty, indicating that the
+** query has completed.
+*/
+static int rtreeStepToLeaf(RtreeCursor *pCur){
+  RtreeSearchPoint *p;
+  Rtree *pRtree = RTREE_OF_CURSOR(pCur);
+  RtreeNode *pNode;
+  int eWithin;
+  int rc = SQLITE_OK;
+  int nCell;
+  int nConstraint = pCur->nConstraint;
+  int ii;
+  int eInt;
+  RtreeSearchPoint x;
+
+  eInt = pRtree->eCoordType==RTREE_COORD_INT32;
+  while( (p = rtreeSearchPointFirst(pCur))!=0 && p->iLevel>0 ){
+    u8 *pCellData;
+    pNode = rtreeNodeOfFirstSearchPoint(pCur, &rc);
+    if( rc ) return rc;
+    nCell = NCELL(pNode);
+    assert( nCell<200 );
+    pCellData = pNode->zData + (4+pRtree->nBytesPerCell*p->iCell);
+    while( p->iCell<nCell ){
+      sqlite3_rtree_dbl rScore = (sqlite3_rtree_dbl)-1;
+      eWithin = FULLY_WITHIN;
+      for(ii=0; ii<nConstraint; ii++){
+        RtreeConstraint *pConstraint = pCur->aConstraint + ii;
+        if( pConstraint->op>=RTREE_MATCH ){
+          rc = rtreeCallbackConstraint(pConstraint, eInt, pCellData, p,
+                                       &rScore, &eWithin);
+          if( rc ) return rc;
+        }else if( p->iLevel==1 ){
+          rtreeLeafConstraint(pConstraint, eInt, pCellData, &eWithin);
+        }else{
+          rtreeNonleafConstraint(pConstraint, eInt, pCellData, &eWithin);
+        }
+        if( eWithin==NOT_WITHIN ){
+          p->iCell++;
+          pCellData += pRtree->nBytesPerCell;
+          break;
+        }
+      }
+      if( eWithin==NOT_WITHIN ) continue;
+      p->iCell++;
+      x.iLevel = p->iLevel - 1;
+      if( x.iLevel ){
+        x.id = readInt64(pCellData);
+        for(ii=0; ii<pCur->nPoint; ii++){
+          if( pCur->aPoint[ii].id==x.id ){
+            RTREE_IS_CORRUPT(pRtree);
+            return SQLITE_CORRUPT_VTAB;
+          }
+        }
+        x.iCell = 0;
+      }else{
+        x.id = p->id;
+        x.iCell = p->iCell - 1;
+      }
+      if( p->iCell>=nCell ){
+        RTREE_QUEUE_TRACE(pCur, "POP-S:");
+        rtreeSearchPointPop(pCur);
+      }
+      if( rScore<RTREE_ZERO ) rScore = RTREE_ZERO;
+      p = rtreeSearchPointNew(pCur, rScore, x.iLevel);
+      if( p==0 ) return SQLITE_NOMEM;
+      p->eWithin = (u8)eWithin;
+      p->id = x.id;
+      p->iCell = x.iCell;
+      RTREE_QUEUE_TRACE(pCur, "PUSH-S:");
+      break;
+    }
+    if( p->iCell>=nCell ){
+      RTREE_QUEUE_TRACE(pCur, "POP-Se:");
+      rtreeSearchPointPop(pCur);
+    }
+  }
+  pCur->atEOF = p==0;
+  return SQLITE_OK;
+}
+
+/*
+** Rtree virtual table module xNext method.
+*/
+static int rtreeNext(sqlite3_vtab_cursor *pVtabCursor){
+  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+  int rc = SQLITE_OK;
+
+  /* Move to the next entry that matches the configured constraints. */
+  RTREE_QUEUE_TRACE(pCsr, "POP-Nx:");
+  if( pCsr->bAuxValid ){
+    pCsr->bAuxValid = 0;
+    sqlite3_reset(pCsr->pReadAux);
+  }
+  rtreeSearchPointPop(pCsr);
+  rc = rtreeStepToLeaf(pCsr);
+  return rc;
+}
+
+/*
+** Rtree virtual table module xRowid method.
+*/
+static int rtreeRowid(sqlite3_vtab_cursor *pVtabCursor, sqlite_int64 *pRowid){
+  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+  RtreeSearchPoint *p = rtreeSearchPointFirst(pCsr);
+  int rc = SQLITE_OK;
+  RtreeNode *pNode = rtreeNodeOfFirstSearchPoint(pCsr, &rc);
+  if( rc==SQLITE_OK && ALWAYS(p) ){
+    if( p->iCell>=NCELL(pNode) ){
+      rc = SQLITE_ABORT;
+    }else{
+      *pRowid = nodeGetRowid(RTREE_OF_CURSOR(pCsr), pNode, p->iCell);
+    }
+  }
+  return rc;
+}
+
+/*
+** Rtree virtual table module xColumn method.
+*/
+static int rtreeColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
+  Rtree *pRtree = (Rtree *)cur->pVtab;
+  RtreeCursor *pCsr = (RtreeCursor *)cur;
+  RtreeSearchPoint *p = rtreeSearchPointFirst(pCsr);
+  RtreeCoord c;
+  int rc = SQLITE_OK;
+  RtreeNode *pNode = rtreeNodeOfFirstSearchPoint(pCsr, &rc);
+
+  if( rc ) return rc;
+  if( NEVER(p==0) ) return SQLITE_OK;
+  if( p->iCell>=NCELL(pNode) ) return SQLITE_ABORT;
+  if( i==0 ){
+    sqlite3_result_int64(ctx, nodeGetRowid(pRtree, pNode, p->iCell));
+  }else if( i<=pRtree->nDim2 ){
+    nodeGetCoord(pRtree, pNode, p->iCell, i-1, &c);
+#ifndef SQLITE_RTREE_INT_ONLY
+    if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+      sqlite3_result_double(ctx, c.f);
+    }else
+#endif
+    {
+      assert( pRtree->eCoordType==RTREE_COORD_INT32 );
+      sqlite3_result_int(ctx, c.i);
+    }
+  }else{
+    if( !pCsr->bAuxValid ){
+      if( pCsr->pReadAux==0 ){
+        rc = sqlite3_prepare_v3(pRtree->db, pRtree->zReadAuxSql, -1, 0,
+                                &pCsr->pReadAux, 0);
+        if( rc ) return rc;
+      }
+      sqlite3_bind_int64(pCsr->pReadAux, 1,
+          nodeGetRowid(pRtree, pNode, p->iCell));
+      rc = sqlite3_step(pCsr->pReadAux);
+      if( rc==SQLITE_ROW ){
+        pCsr->bAuxValid = 1;
+      }else{
+        sqlite3_reset(pCsr->pReadAux);
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+        return rc;
+      }
+    }
+    sqlite3_result_value(ctx,
+         sqlite3_column_value(pCsr->pReadAux, i - pRtree->nDim2 + 1));
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Use nodeAcquire() to obtain the leaf node containing the record with
+** rowid iRowid. If successful, set *ppLeaf to point to the node and
+** return SQLITE_OK. If there is no such record in the table, set
+** *ppLeaf to 0 and return SQLITE_OK. If an error occurs, set *ppLeaf
+** to zero and return an SQLite error code.
+*/
+static int findLeafNode(
+  Rtree *pRtree,              /* RTree to search */
+  i64 iRowid,                 /* The rowid searching for */
+  RtreeNode **ppLeaf,         /* Write the node here */
+  sqlite3_int64 *piNode       /* Write the node-id here */
+){
+  int rc;
+  *ppLeaf = 0;
+  sqlite3_bind_int64(pRtree->pReadRowid, 1, iRowid);
+  if( sqlite3_step(pRtree->pReadRowid)==SQLITE_ROW ){
+    i64 iNode = sqlite3_column_int64(pRtree->pReadRowid, 0);
+    if( piNode ) *piNode = iNode;
+    rc = nodeAcquire(pRtree, iNode, 0, ppLeaf);
+    sqlite3_reset(pRtree->pReadRowid);
+  }else{
+    rc = sqlite3_reset(pRtree->pReadRowid);
+  }
+  return rc;
+}
+
+/*
+** This function is called to configure the RtreeConstraint object passed
+** as the second argument for a MATCH constraint. The value passed as the
+** first argument to this function is the right-hand operand to the MATCH
+** operator.
+*/
+static int deserializeGeometry(sqlite3_value *pValue, RtreeConstraint *pCons){
+  RtreeMatchArg *pBlob, *pSrc;       /* BLOB returned by geometry function */
+  sqlite3_rtree_query_info *pInfo;   /* Callback information */
+
+  pSrc = sqlite3_value_pointer(pValue, "RtreeMatchArg");
+  if( pSrc==0 ) return SQLITE_ERROR;
+  pInfo = (sqlite3_rtree_query_info*)
+                sqlite3_malloc64( sizeof(*pInfo)+pSrc->iSize );
+  if( !pInfo ) return SQLITE_NOMEM;
+  memset(pInfo, 0, sizeof(*pInfo));
+  pBlob = (RtreeMatchArg*)&pInfo[1];
+  memcpy(pBlob, pSrc, pSrc->iSize);
+  pInfo->pContext = pBlob->cb.pContext;
+  pInfo->nParam = pBlob->nParam;
+  pInfo->aParam = pBlob->aParam;
+  pInfo->apSqlParam = pBlob->apSqlParam;
+
+  if( pBlob->cb.xGeom ){
+    pCons->u.xGeom = pBlob->cb.xGeom;
+  }else{
+    pCons->op = RTREE_QUERY;
+    pCons->u.xQueryFunc = pBlob->cb.xQueryFunc;
+  }
+  pCons->pInfo = pInfo;
+  return SQLITE_OK;
+}
+
+SQLITE_PRIVATE int sqlite3IntFloatCompare(i64,double);
+
+/*
+** Rtree virtual table module xFilter method.
+*/
+static int rtreeFilter(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  Rtree *pRtree = (Rtree *)pVtabCursor->pVtab;
+  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+  RtreeNode *pRoot = 0;
+  int ii;
+  int rc = SQLITE_OK;
+  int iCell = 0;
+
+  rtreeReference(pRtree);
+
+  /* Reset the cursor to the same state as rtreeOpen() leaves it in. */
+  resetCursor(pCsr);
+
+  pCsr->iStrategy = idxNum;
+  if( idxNum==1 ){
+    /* Special case - lookup by rowid. */
+    RtreeNode *pLeaf;        /* Leaf on which the required cell resides */
+    RtreeSearchPoint *p;     /* Search point for the leaf */
+    i64 iRowid = sqlite3_value_int64(argv[0]);
+    i64 iNode = 0;
+    int eType = sqlite3_value_numeric_type(argv[0]);
+    if( eType==SQLITE_INTEGER
+     || (eType==SQLITE_FLOAT
+         && 0==sqlite3IntFloatCompare(iRowid,sqlite3_value_double(argv[0])))
+    ){
+      rc = findLeafNode(pRtree, iRowid, &pLeaf, &iNode);
+    }else{
+      rc = SQLITE_OK;
+      pLeaf = 0;
+    }
+    if( rc==SQLITE_OK && pLeaf!=0 ){
+      p = rtreeSearchPointNew(pCsr, RTREE_ZERO, 0);
+      assert( p!=0 );  /* Always returns pCsr->sPoint */
+      pCsr->aNode[0] = pLeaf;
+      p->id = iNode;
+      p->eWithin = PARTLY_WITHIN;
+      rc = nodeRowidIndex(pRtree, pLeaf, iRowid, &iCell);
+      p->iCell = (u8)iCell;
+      RTREE_QUEUE_TRACE(pCsr, "PUSH-F1:");
+    }else{
+      pCsr->atEOF = 1;
+    }
+  }else{
+    /* Normal case - r-tree scan. Set up the RtreeCursor.aConstraint array
+    ** with the configured constraints.
+    */
+    rc = nodeAcquire(pRtree, 1, 0, &pRoot);
+    if( rc==SQLITE_OK && argc>0 ){
+      pCsr->aConstraint = sqlite3_malloc64(sizeof(RtreeConstraint)*argc);
+      pCsr->nConstraint = argc;
+      if( !pCsr->aConstraint ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(pCsr->aConstraint, 0, sizeof(RtreeConstraint)*argc);
+        memset(pCsr->anQueue, 0, sizeof(u32)*(pRtree->iDepth + 1));
+        assert( (idxStr==0 && argc==0)
+                || (idxStr && (int)strlen(idxStr)==argc*2) );
+        for(ii=0; ii<argc; ii++){
+          RtreeConstraint *p = &pCsr->aConstraint[ii];
+          int eType = sqlite3_value_numeric_type(argv[ii]);
+          p->op = idxStr[ii*2];
+          p->iCoord = idxStr[ii*2+1]-'0';
+          if( p->op>=RTREE_MATCH ){
+            /* A MATCH operator. The right-hand-side must be a blob that
+            ** can be cast into an RtreeMatchArg object. One created using
+            ** an sqlite3_rtree_geometry_callback() SQL user function.
+            */
+            rc = deserializeGeometry(argv[ii], p);
+            if( rc!=SQLITE_OK ){
+              break;
+            }
+            p->pInfo->nCoord = pRtree->nDim2;
+            p->pInfo->anQueue = pCsr->anQueue;
+            p->pInfo->mxLevel = pRtree->iDepth + 1;
+          }else if( eType==SQLITE_INTEGER ){
+            sqlite3_int64 iVal = sqlite3_value_int64(argv[ii]);
+#ifdef SQLITE_RTREE_INT_ONLY
+            p->u.rValue = iVal;
+#else
+            p->u.rValue = (double)iVal;
+            if( iVal>=((sqlite3_int64)1)<<48
+             || iVal<=-(((sqlite3_int64)1)<<48)
+            ){
+              if( p->op==RTREE_LT ) p->op = RTREE_LE;
+              if( p->op==RTREE_GT ) p->op = RTREE_GE;
+            }
+#endif
+          }else if( eType==SQLITE_FLOAT ){
+#ifdef SQLITE_RTREE_INT_ONLY
+            p->u.rValue = sqlite3_value_int64(argv[ii]);
+#else
+            p->u.rValue = sqlite3_value_double(argv[ii]);
+#endif
+          }else{
+            p->u.rValue = RTREE_ZERO;
+            if( eType==SQLITE_NULL ){
+              p->op = RTREE_FALSE;
+            }else if( p->op==RTREE_LT || p->op==RTREE_LE ){
+              p->op = RTREE_TRUE;
+            }else{
+              p->op = RTREE_FALSE;
+            }
+          }
+        }
+      }
+    }
+    if( rc==SQLITE_OK ){
+      RtreeSearchPoint *pNew;
+      assert( pCsr->bPoint==0 );  /* Due to the resetCursor() call above */
+      pNew = rtreeSearchPointNew(pCsr, RTREE_ZERO, (u8)(pRtree->iDepth+1));
+      if( NEVER(pNew==0) ){       /* Because pCsr->bPoint was FALSE */
+        return SQLITE_NOMEM;
+      }
+      pNew->id = 1;
+      pNew->iCell = 0;
+      pNew->eWithin = PARTLY_WITHIN;
+      assert( pCsr->bPoint==1 );
+      pCsr->aNode[0] = pRoot;
+      pRoot = 0;
+      RTREE_QUEUE_TRACE(pCsr, "PUSH-Fm:");
+      rc = rtreeStepToLeaf(pCsr);
+    }
+  }
+
+  nodeRelease(pRtree, pRoot);
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+/*
+** Rtree virtual table module xBestIndex method. There are three
+** table scan strategies to choose from (in order from most to
+** least desirable):
+**
+**   idxNum     idxStr        Strategy
+**   ------------------------------------------------
+**     1        Unused        Direct lookup by rowid.
+**     2        See below     R-tree query or full-table scan.
+**   ------------------------------------------------
+**
+** If strategy 1 is used, then idxStr is not meaningful. If strategy
+** 2 is used, idxStr is formatted to contain 2 bytes for each
+** constraint used. The first two bytes of idxStr correspond to
+** the constraint in sqlite3_index_info.aConstraintUsage[] with
+** (argvIndex==1) etc.
+**
+** The first of each pair of bytes in idxStr identifies the constraint
+** operator as follows:
+**
+**   Operator    Byte Value
+**   ----------------------
+**      =        0x41 ('A')
+**     <=        0x42 ('B')
+**      <        0x43 ('C')
+**     >=        0x44 ('D')
+**      >        0x45 ('E')
+**   MATCH       0x46 ('F')
+**   ----------------------
+**
+** The second of each pair of bytes identifies the coordinate column
+** to which the constraint applies. The leftmost coordinate column
+** is 'a', the second from the left 'b' etc.
+*/
+static int rtreeBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  Rtree *pRtree = (Rtree*)tab;
+  int rc = SQLITE_OK;
+  int ii;
+  int bMatch = 0;                 /* True if there exists a MATCH constraint */
+  i64 nRow;                       /* Estimated rows returned by this scan */
+
+  int iIdx = 0;
+  char zIdxStr[RTREE_MAX_DIMENSIONS*8+1];
+  memset(zIdxStr, 0, sizeof(zIdxStr));
+
+  /* Check if there exists a MATCH constraint - even an unusable one. If there
+  ** is, do not consider the lookup-by-rowid plan as using such a plan would
+  ** require the VDBE to evaluate the MATCH constraint, which is not currently
+  ** possible. */
+  for(ii=0; ii<pIdxInfo->nConstraint; ii++){
+    if( pIdxInfo->aConstraint[ii].op==SQLITE_INDEX_CONSTRAINT_MATCH ){
+      bMatch = 1;
+    }
+  }
+
+  assert( pIdxInfo->idxStr==0 );
+  for(ii=0; ii<pIdxInfo->nConstraint && iIdx<(int)(sizeof(zIdxStr)-1); ii++){
+    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[ii];
+
+    if( bMatch==0 && p->usable
+     && p->iColumn<=0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ
+    ){
+      /* We have an equality constraint on the rowid. Use strategy 1. */
+      int jj;
+      for(jj=0; jj<ii; jj++){
+        pIdxInfo->aConstraintUsage[jj].argvIndex = 0;
+        pIdxInfo->aConstraintUsage[jj].omit = 0;
+      }
+      pIdxInfo->idxNum = 1;
+      pIdxInfo->aConstraintUsage[ii].argvIndex = 1;
+      pIdxInfo->aConstraintUsage[jj].omit = 1;
+
+      /* This strategy involves a two rowid lookups on an B-Tree structures
+      ** and then a linear search of an R-Tree node. This should be
+      ** considered almost as quick as a direct rowid lookup (for which
+      ** sqlite uses an internal cost of 0.0). It is expected to return
+      ** a single row.
+      */
+      pIdxInfo->estimatedCost = 30.0;
+      pIdxInfo->estimatedRows = 1;
+      pIdxInfo->idxFlags = SQLITE_INDEX_SCAN_UNIQUE;
+      return SQLITE_OK;
+    }
+
+    if( p->usable
+    && ((p->iColumn>0 && p->iColumn<=pRtree->nDim2)
+        || p->op==SQLITE_INDEX_CONSTRAINT_MATCH)
+    ){
+      u8 op;
+      u8 doOmit = 1;
+      switch( p->op ){
+        case SQLITE_INDEX_CONSTRAINT_EQ:    op = RTREE_EQ;    doOmit = 0; break;
+        case SQLITE_INDEX_CONSTRAINT_GT:    op = RTREE_GT;    doOmit = 0; break;
+        case SQLITE_INDEX_CONSTRAINT_LE:    op = RTREE_LE;    break;
+        case SQLITE_INDEX_CONSTRAINT_LT:    op = RTREE_LT;    doOmit = 0; break;
+        case SQLITE_INDEX_CONSTRAINT_GE:    op = RTREE_GE;    break;
+        case SQLITE_INDEX_CONSTRAINT_MATCH: op = RTREE_MATCH; break;
+        default:                            op = 0;           break;
+      }
+      if( op ){
+        zIdxStr[iIdx++] = op;
+        zIdxStr[iIdx++] = (char)(p->iColumn - 1 + '0');
+        pIdxInfo->aConstraintUsage[ii].argvIndex = (iIdx/2);
+        pIdxInfo->aConstraintUsage[ii].omit = doOmit;
+      }
+    }
+  }
+
+  pIdxInfo->idxNum = 2;
+  pIdxInfo->needToFreeIdxStr = 1;
+  if( iIdx>0 ){
+    pIdxInfo->idxStr = sqlite3_malloc( iIdx+1 );
+    if( pIdxInfo->idxStr==0 ){
+      return SQLITE_NOMEM;
+    }
+    memcpy(pIdxInfo->idxStr, zIdxStr, iIdx+1);
+  }
+
+  nRow = pRtree->nRowEst >> (iIdx/2);
+  pIdxInfo->estimatedCost = (double)6.0 * (double)nRow;
+  pIdxInfo->estimatedRows = nRow;
+
+  return rc;
+}
+
+/*
+** Return the N-dimensional volumn of the cell stored in *p.
+*/
+static RtreeDValue cellArea(Rtree *pRtree, RtreeCell *p){
+  RtreeDValue area = (RtreeDValue)1;
+  assert( pRtree->nDim>=1 && pRtree->nDim<=5 );
+#ifndef SQLITE_RTREE_INT_ONLY
+  if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+    switch( pRtree->nDim ){
+      case 5:  area  = p->aCoord[9].f - p->aCoord[8].f;
+      case 4:  area *= p->aCoord[7].f - p->aCoord[6].f;
+      case 3:  area *= p->aCoord[5].f - p->aCoord[4].f;
+      case 2:  area *= p->aCoord[3].f - p->aCoord[2].f;
+      default: area *= p->aCoord[1].f - p->aCoord[0].f;
+    }
+  }else
+#endif
+  {
+    switch( pRtree->nDim ){
+      case 5:  area  = (i64)p->aCoord[9].i - (i64)p->aCoord[8].i;
+      case 4:  area *= (i64)p->aCoord[7].i - (i64)p->aCoord[6].i;
+      case 3:  area *= (i64)p->aCoord[5].i - (i64)p->aCoord[4].i;
+      case 2:  area *= (i64)p->aCoord[3].i - (i64)p->aCoord[2].i;
+      default: area *= (i64)p->aCoord[1].i - (i64)p->aCoord[0].i;
+    }
+  }
+  return area;
+}
+
+/*
+** Return the margin length of cell p. The margin length is the sum
+** of the objects size in each dimension.
+*/
+static RtreeDValue cellMargin(Rtree *pRtree, RtreeCell *p){
+  RtreeDValue margin = 0;
+  int ii = pRtree->nDim2 - 2;
+  do{
+    margin += (DCOORD(p->aCoord[ii+1]) - DCOORD(p->aCoord[ii]));
+    ii -= 2;
+  }while( ii>=0 );
+  return margin;
+}
+
+/*
+** Store the union of cells p1 and p2 in p1.
+*/
+static void cellUnion(Rtree *pRtree, RtreeCell *p1, RtreeCell *p2){
+  int ii = 0;
+  if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+    do{
+      p1->aCoord[ii].f = MIN(p1->aCoord[ii].f, p2->aCoord[ii].f);
+      p1->aCoord[ii+1].f = MAX(p1->aCoord[ii+1].f, p2->aCoord[ii+1].f);
+      ii += 2;
+    }while( ii<pRtree->nDim2 );
+  }else{
+    do{
+      p1->aCoord[ii].i = MIN(p1->aCoord[ii].i, p2->aCoord[ii].i);
+      p1->aCoord[ii+1].i = MAX(p1->aCoord[ii+1].i, p2->aCoord[ii+1].i);
+      ii += 2;
+    }while( ii<pRtree->nDim2 );
+  }
+}
+
+/*
+** Return true if the area covered by p2 is a subset of the area covered
+** by p1. False otherwise.
+*/
+static int cellContains(Rtree *pRtree, RtreeCell *p1, RtreeCell *p2){
+  int ii;
+  if( pRtree->eCoordType==RTREE_COORD_INT32 ){
+    for(ii=0; ii<pRtree->nDim2; ii+=2){
+      RtreeCoord *a1 = &p1->aCoord[ii];
+      RtreeCoord *a2 = &p2->aCoord[ii];
+      if( a2[0].i<a1[0].i || a2[1].i>a1[1].i ) return 0;
+    }
+  }else{
+    for(ii=0; ii<pRtree->nDim2; ii+=2){
+      RtreeCoord *a1 = &p1->aCoord[ii];
+      RtreeCoord *a2 = &p2->aCoord[ii];
+      if( a2[0].f<a1[0].f || a2[1].f>a1[1].f ) return 0;
+    }
+  }
+  return 1;
+}
+
+static RtreeDValue cellOverlap(
+  Rtree *pRtree,
+  RtreeCell *p,
+  RtreeCell *aCell,
+  int nCell
+){
+  int ii;
+  RtreeDValue overlap = RTREE_ZERO;
+  for(ii=0; ii<nCell; ii++){
+    int jj;
+    RtreeDValue o = (RtreeDValue)1;
+    for(jj=0; jj<pRtree->nDim2; jj+=2){
+      RtreeDValue x1, x2;
+      x1 = MAX(DCOORD(p->aCoord[jj]), DCOORD(aCell[ii].aCoord[jj]));
+      x2 = MIN(DCOORD(p->aCoord[jj+1]), DCOORD(aCell[ii].aCoord[jj+1]));
+      if( x2<x1 ){
+        o = (RtreeDValue)0;
+        break;
+      }else{
+        o = o * (x2-x1);
+      }
+    }
+    overlap += o;
+  }
+  return overlap;
+}
+
+
+/*
+** This function implements the ChooseLeaf algorithm from Gutman[84].
+** ChooseSubTree in r*tree terminology.
+*/
+static int ChooseLeaf(
+  Rtree *pRtree,               /* Rtree table */
+  RtreeCell *pCell,            /* Cell to insert into rtree */
+  int iHeight,                 /* Height of sub-tree rooted at pCell */
+  RtreeNode **ppLeaf           /* OUT: Selected leaf page */
+){
+  int rc;
+  int ii;
+  RtreeNode *pNode = 0;
+  rc = nodeAcquire(pRtree, 1, 0, &pNode);
+
+  for(ii=0; rc==SQLITE_OK && ii<(pRtree->iDepth-iHeight); ii++){
+    int iCell;
+    sqlite3_int64 iBest = 0;
+    int bFound = 0;
+    RtreeDValue fMinGrowth = RTREE_ZERO;
+    RtreeDValue fMinArea = RTREE_ZERO;
+    int nCell = NCELL(pNode);
+    RtreeNode *pChild = 0;
+
+    /* First check to see if there is are any cells in pNode that completely
+    ** contains pCell.  If two or more cells in pNode completely contain pCell
+    ** then pick the smallest.
+    */
+    for(iCell=0; iCell<nCell; iCell++){
+      RtreeCell cell;
+      nodeGetCell(pRtree, pNode, iCell, &cell);
+      if( cellContains(pRtree, &cell, pCell) ){
+        RtreeDValue area = cellArea(pRtree, &cell);
+        if( bFound==0 || area<fMinArea ){
+          iBest = cell.iRowid;
+          fMinArea = area;
+          bFound = 1;
+        }
+      }
+    }
+    if( !bFound ){
+      /* No cells of pNode will completely contain pCell.  So pick the
+      ** cell of pNode that grows by the least amount when pCell is added.
+      ** Break ties by selecting the smaller cell.
+      */
+      for(iCell=0; iCell<nCell; iCell++){
+        RtreeCell cell;
+        RtreeDValue growth;
+        RtreeDValue area;
+        nodeGetCell(pRtree, pNode, iCell, &cell);
+        area = cellArea(pRtree, &cell);
+        cellUnion(pRtree, &cell, pCell);
+        growth = cellArea(pRtree, &cell)-area;
+        if( iCell==0
+         || growth<fMinGrowth
+         || (growth==fMinGrowth && area<fMinArea)
+        ){
+          fMinGrowth = growth;
+          fMinArea = area;
+          iBest = cell.iRowid;
+        }
+      }
+    }
+
+    rc = nodeAcquire(pRtree, iBest, pNode, &pChild);
+    nodeRelease(pRtree, pNode);
+    pNode = pChild;
+  }
+
+  *ppLeaf = pNode;
+  return rc;
+}
+
+/*
+** A cell with the same content as pCell has just been inserted into
+** the node pNode. This function updates the bounding box cells in
+** all ancestor elements.
+*/
+static int AdjustTree(
+  Rtree *pRtree,                    /* Rtree table */
+  RtreeNode *pNode,                 /* Adjust ancestry of this node. */
+  RtreeCell *pCell                  /* This cell was just inserted */
+){
+  RtreeNode *p = pNode;
+  int cnt = 0;
+  int rc;
+  while( p->pParent ){
+    RtreeNode *pParent = p->pParent;
+    RtreeCell cell;
+    int iCell;
+
+    cnt++;
+    if( NEVER(cnt>100) ){
+      RTREE_IS_CORRUPT(pRtree);
+      return SQLITE_CORRUPT_VTAB;
+    }
+    rc = nodeParentIndex(pRtree, p, &iCell);
+    if( NEVER(rc!=SQLITE_OK) ){
+      RTREE_IS_CORRUPT(pRtree);
+      return SQLITE_CORRUPT_VTAB;
+    }
+
+    nodeGetCell(pRtree, pParent, iCell, &cell);
+    if( !cellContains(pRtree, &cell, pCell) ){
+      cellUnion(pRtree, &cell, pCell);
+      nodeOverwriteCell(pRtree, pParent, &cell, iCell);
+    }
+
+    p = pParent;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Write mapping (iRowid->iNode) to the <rtree>_rowid table.
+*/
+static int rowidWrite(Rtree *pRtree, sqlite3_int64 iRowid, sqlite3_int64 iNode){
+  sqlite3_bind_int64(pRtree->pWriteRowid, 1, iRowid);
+  sqlite3_bind_int64(pRtree->pWriteRowid, 2, iNode);
+  sqlite3_step(pRtree->pWriteRowid);
+  return sqlite3_reset(pRtree->pWriteRowid);
+}
+
+/*
+** Write mapping (iNode->iPar) to the <rtree>_parent table.
+*/
+static int parentWrite(Rtree *pRtree, sqlite3_int64 iNode, sqlite3_int64 iPar){
+  sqlite3_bind_int64(pRtree->pWriteParent, 1, iNode);
+  sqlite3_bind_int64(pRtree->pWriteParent, 2, iPar);
+  sqlite3_step(pRtree->pWriteParent);
+  return sqlite3_reset(pRtree->pWriteParent);
+}
+
+static int rtreeInsertCell(Rtree *, RtreeNode *, RtreeCell *, int);
+
+
+
+/*
+** Arguments aIdx, aCell and aSpare all point to arrays of size
+** nIdx. The aIdx array contains the set of integers from 0 to
+** (nIdx-1) in no particular order. This function sorts the values
+** in aIdx according to dimension iDim of the cells in aCell. The
+** minimum value of dimension iDim is considered first, the
+** maximum used to break ties.
+**
+** The aSpare array is used as temporary working space by the
+** sorting algorithm.
+*/
+static void SortByDimension(
+  Rtree *pRtree,
+  int *aIdx,
+  int nIdx,
+  int iDim,
+  RtreeCell *aCell,
+  int *aSpare
+){
+  if( nIdx>1 ){
+
+    int iLeft = 0;
+    int iRight = 0;
+
+    int nLeft = nIdx/2;
+    int nRight = nIdx-nLeft;
+    int *aLeft = aIdx;
+    int *aRight = &aIdx[nLeft];
+
+    SortByDimension(pRtree, aLeft, nLeft, iDim, aCell, aSpare);
+    SortByDimension(pRtree, aRight, nRight, iDim, aCell, aSpare);
+
+    memcpy(aSpare, aLeft, sizeof(int)*nLeft);
+    aLeft = aSpare;
+    while( iLeft<nLeft || iRight<nRight ){
+      RtreeDValue xleft1 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2]);
+      RtreeDValue xleft2 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2+1]);
+      RtreeDValue xright1 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2]);
+      RtreeDValue xright2 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2+1]);
+      if( (iLeft!=nLeft) && ((iRight==nRight)
+       || (xleft1<xright1)
+       || (xleft1==xright1 && xleft2<xright2)
+      )){
+        aIdx[iLeft+iRight] = aLeft[iLeft];
+        iLeft++;
+      }else{
+        aIdx[iLeft+iRight] = aRight[iRight];
+        iRight++;
+      }
+    }
+
+#if 0
+    /* Check that the sort worked */
+    {
+      int jj;
+      for(jj=1; jj<nIdx; jj++){
+        RtreeDValue xleft1 = aCell[aIdx[jj-1]].aCoord[iDim*2];
+        RtreeDValue xleft2 = aCell[aIdx[jj-1]].aCoord[iDim*2+1];
+        RtreeDValue xright1 = aCell[aIdx[jj]].aCoord[iDim*2];
+        RtreeDValue xright2 = aCell[aIdx[jj]].aCoord[iDim*2+1];
+        assert( xleft1<=xright1 && (xleft1<xright1 || xleft2<=xright2) );
+      }
+    }
+#endif
+  }
+}
+
+/*
+** Implementation of the R*-tree variant of SplitNode from Beckman[1990].
+*/
+static int splitNodeStartree(
+  Rtree *pRtree,
+  RtreeCell *aCell,
+  int nCell,
+  RtreeNode *pLeft,
+  RtreeNode *pRight,
+  RtreeCell *pBboxLeft,
+  RtreeCell *pBboxRight
+){
+  int **aaSorted;
+  int *aSpare;
+  int ii;
+
+  int iBestDim = 0;
+  int iBestSplit = 0;
+  RtreeDValue fBestMargin = RTREE_ZERO;
+
+  sqlite3_int64 nByte = (pRtree->nDim+1)*(sizeof(int*)+nCell*sizeof(int));
+
+  aaSorted = (int **)sqlite3_malloc64(nByte);
+  if( !aaSorted ){
+    return SQLITE_NOMEM;
+  }
+
+  aSpare = &((int *)&aaSorted[pRtree->nDim])[pRtree->nDim*nCell];
+  memset(aaSorted, 0, nByte);
+  for(ii=0; ii<pRtree->nDim; ii++){
+    int jj;
+    aaSorted[ii] = &((int *)&aaSorted[pRtree->nDim])[ii*nCell];
+    for(jj=0; jj<nCell; jj++){
+      aaSorted[ii][jj] = jj;
+    }
+    SortByDimension(pRtree, aaSorted[ii], nCell, ii, aCell, aSpare);
+  }
+
+  for(ii=0; ii<pRtree->nDim; ii++){
+    RtreeDValue margin = RTREE_ZERO;
+    RtreeDValue fBestOverlap = RTREE_ZERO;
+    RtreeDValue fBestArea = RTREE_ZERO;
+    int iBestLeft = 0;
+    int nLeft;
+
+    for(
+      nLeft=RTREE_MINCELLS(pRtree);
+      nLeft<=(nCell-RTREE_MINCELLS(pRtree));
+      nLeft++
+    ){
+      RtreeCell left;
+      RtreeCell right;
+      int kk;
+      RtreeDValue overlap;
+      RtreeDValue area;
+
+      memcpy(&left, &aCell[aaSorted[ii][0]], sizeof(RtreeCell));
+      memcpy(&right, &aCell[aaSorted[ii][nCell-1]], sizeof(RtreeCell));
+      for(kk=1; kk<(nCell-1); kk++){
+        if( kk<nLeft ){
+          cellUnion(pRtree, &left, &aCell[aaSorted[ii][kk]]);
+        }else{
+          cellUnion(pRtree, &right, &aCell[aaSorted[ii][kk]]);
+        }
+      }
+      margin += cellMargin(pRtree, &left);
+      margin += cellMargin(pRtree, &right);
+      overlap = cellOverlap(pRtree, &left, &right, 1);
+      area = cellArea(pRtree, &left) + cellArea(pRtree, &right);
+      if( (nLeft==RTREE_MINCELLS(pRtree))
+       || (overlap<fBestOverlap)
+       || (overlap==fBestOverlap && area<fBestArea)
+      ){
+        iBestLeft = nLeft;
+        fBestOverlap = overlap;
+        fBestArea = area;
+      }
+    }
+
+    if( ii==0 || margin<fBestMargin ){
+      iBestDim = ii;
+      fBestMargin = margin;
+      iBestSplit = iBestLeft;
+    }
+  }
+
+  memcpy(pBboxLeft, &aCell[aaSorted[iBestDim][0]], sizeof(RtreeCell));
+  memcpy(pBboxRight, &aCell[aaSorted[iBestDim][iBestSplit]], sizeof(RtreeCell));
+  for(ii=0; ii<nCell; ii++){
+    RtreeNode *pTarget = (ii<iBestSplit)?pLeft:pRight;
+    RtreeCell *pBbox = (ii<iBestSplit)?pBboxLeft:pBboxRight;
+    RtreeCell *pCell = &aCell[aaSorted[iBestDim][ii]];
+    nodeInsertCell(pRtree, pTarget, pCell);
+    cellUnion(pRtree, pBbox, pCell);
+  }
+
+  sqlite3_free(aaSorted);
+  return SQLITE_OK;
+}
+
+
+static int updateMapping(
+  Rtree *pRtree,
+  i64 iRowid,
+  RtreeNode *pNode,
+  int iHeight
+){
+  int (*xSetMapping)(Rtree *, sqlite3_int64, sqlite3_int64);
+  xSetMapping = ((iHeight==0)?rowidWrite:parentWrite);
+  if( iHeight>0 ){
+    RtreeNode *pChild = nodeHashLookup(pRtree, iRowid);
+    RtreeNode *p;
+    for(p=pNode; p; p=p->pParent){
+      if( p==pChild ) return SQLITE_CORRUPT_VTAB;
+    }
+    if( pChild ){
+      nodeRelease(pRtree, pChild->pParent);
+      nodeReference(pNode);
+      pChild->pParent = pNode;
+    }
+  }
+  if( NEVER(pNode==0) ) return SQLITE_ERROR;
+  return xSetMapping(pRtree, iRowid, pNode->iNode);
+}
+
+static int SplitNode(
+  Rtree *pRtree,
+  RtreeNode *pNode,
+  RtreeCell *pCell,
+  int iHeight
+){
+  int i;
+  int newCellIsRight = 0;
+
+  int rc = SQLITE_OK;
+  int nCell = NCELL(pNode);
+  RtreeCell *aCell;
+  int *aiUsed;
+
+  RtreeNode *pLeft = 0;
+  RtreeNode *pRight = 0;
+
+  RtreeCell leftbbox;
+  RtreeCell rightbbox;
+
+  /* Allocate an array and populate it with a copy of pCell and
+  ** all cells from node pLeft. Then zero the original node.
+  */
+  aCell = sqlite3_malloc64((sizeof(RtreeCell)+sizeof(int))*(nCell+1));
+  if( !aCell ){
+    rc = SQLITE_NOMEM;
+    goto splitnode_out;
+  }
+  aiUsed = (int *)&aCell[nCell+1];
+  memset(aiUsed, 0, sizeof(int)*(nCell+1));
+  for(i=0; i<nCell; i++){
+    nodeGetCell(pRtree, pNode, i, &aCell[i]);
+  }
+  nodeZero(pRtree, pNode);
+  memcpy(&aCell[nCell], pCell, sizeof(RtreeCell));
+  nCell++;
+
+  if( pNode->iNode==1 ){
+    pRight = nodeNew(pRtree, pNode);
+    pLeft = nodeNew(pRtree, pNode);
+    pRtree->iDepth++;
+    pNode->isDirty = 1;
+    writeInt16(pNode->zData, pRtree->iDepth);
+  }else{
+    pLeft = pNode;
+    pRight = nodeNew(pRtree, pLeft->pParent);
+    pLeft->nRef++;
+  }
+
+  if( !pLeft || !pRight ){
+    rc = SQLITE_NOMEM;
+    goto splitnode_out;
+  }
+
+  memset(pLeft->zData, 0, pRtree->iNodeSize);
+  memset(pRight->zData, 0, pRtree->iNodeSize);
+
+  rc = splitNodeStartree(pRtree, aCell, nCell, pLeft, pRight,
+                         &leftbbox, &rightbbox);
+  if( rc!=SQLITE_OK ){
+    goto splitnode_out;
+  }
+
+  /* Ensure both child nodes have node numbers assigned to them by calling
+  ** nodeWrite(). Node pRight always needs a node number, as it was created
+  ** by nodeNew() above. But node pLeft sometimes already has a node number.
+  ** In this case avoid the all to nodeWrite().
+  */
+  if( SQLITE_OK!=(rc = nodeWrite(pRtree, pRight))
+   || (0==pLeft->iNode && SQLITE_OK!=(rc = nodeWrite(pRtree, pLeft)))
+  ){
+    goto splitnode_out;
+  }
+
+  rightbbox.iRowid = pRight->iNode;
+  leftbbox.iRowid = pLeft->iNode;
+
+  if( pNode->iNode==1 ){
+    rc = rtreeInsertCell(pRtree, pLeft->pParent, &leftbbox, iHeight+1);
+    if( rc!=SQLITE_OK ){
+      goto splitnode_out;
+    }
+  }else{
+    RtreeNode *pParent = pLeft->pParent;
+    int iCell;
+    rc = nodeParentIndex(pRtree, pLeft, &iCell);
+    if( ALWAYS(rc==SQLITE_OK) ){
+      nodeOverwriteCell(pRtree, pParent, &leftbbox, iCell);
+      rc = AdjustTree(pRtree, pParent, &leftbbox);
+      assert( rc==SQLITE_OK );
+    }
+    if( NEVER(rc!=SQLITE_OK) ){
+      goto splitnode_out;
+    }
+  }
+  if( (rc = rtreeInsertCell(pRtree, pRight->pParent, &rightbbox, iHeight+1)) ){
+    goto splitnode_out;
+  }
+
+  for(i=0; i<NCELL(pRight); i++){
+    i64 iRowid = nodeGetRowid(pRtree, pRight, i);
+    rc = updateMapping(pRtree, iRowid, pRight, iHeight);
+    if( iRowid==pCell->iRowid ){
+      newCellIsRight = 1;
+    }
+    if( rc!=SQLITE_OK ){
+      goto splitnode_out;
+    }
+  }
+  if( pNode->iNode==1 ){
+    for(i=0; i<NCELL(pLeft); i++){
+      i64 iRowid = nodeGetRowid(pRtree, pLeft, i);
+      rc = updateMapping(pRtree, iRowid, pLeft, iHeight);
+      if( rc!=SQLITE_OK ){
+        goto splitnode_out;
+      }
+    }
+  }else if( newCellIsRight==0 ){
+    rc = updateMapping(pRtree, pCell->iRowid, pLeft, iHeight);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = nodeRelease(pRtree, pRight);
+    pRight = 0;
+  }
+  if( rc==SQLITE_OK ){
+    rc = nodeRelease(pRtree, pLeft);
+    pLeft = 0;
+  }
+
+splitnode_out:
+  nodeRelease(pRtree, pRight);
+  nodeRelease(pRtree, pLeft);
+  sqlite3_free(aCell);
+  return rc;
+}
+
+/*
+** If node pLeaf is not the root of the r-tree and its pParent pointer is
+** still NULL, load all ancestor nodes of pLeaf into memory and populate
+** the pLeaf->pParent chain all the way up to the root node.
+**
+** This operation is required when a row is deleted (or updated - an update
+** is implemented as a delete followed by an insert). SQLite provides the
+** rowid of the row to delete, which can be used to find the leaf on which
+** the entry resides (argument pLeaf). Once the leaf is located, this
+** function is called to determine its ancestry.
+*/
+static int fixLeafParent(Rtree *pRtree, RtreeNode *pLeaf){
+  int rc = SQLITE_OK;
+  RtreeNode *pChild = pLeaf;
+  while( rc==SQLITE_OK && pChild->iNode!=1 && pChild->pParent==0 ){
+    int rc2 = SQLITE_OK;          /* sqlite3_reset() return code */
+    sqlite3_bind_int64(pRtree->pReadParent, 1, pChild->iNode);
+    rc = sqlite3_step(pRtree->pReadParent);
+    if( rc==SQLITE_ROW ){
+      RtreeNode *pTest;           /* Used to test for reference loops */
+      i64 iNode;                  /* Node number of parent node */
+
+      /* Before setting pChild->pParent, test that we are not creating a
+      ** loop of references (as we would if, say, pChild==pParent). We don't
+      ** want to do this as it leads to a memory leak when trying to delete
+      ** the referenced counted node structures.
+      */
+      iNode = sqlite3_column_int64(pRtree->pReadParent, 0);
+      for(pTest=pLeaf; pTest && pTest->iNode!=iNode; pTest=pTest->pParent);
+      if( pTest==0 ){
+        rc2 = nodeAcquire(pRtree, iNode, 0, &pChild->pParent);
+      }
+    }
+    rc = sqlite3_reset(pRtree->pReadParent);
+    if( rc==SQLITE_OK ) rc = rc2;
+    if( rc==SQLITE_OK && !pChild->pParent ){
+      RTREE_IS_CORRUPT(pRtree);
+      rc = SQLITE_CORRUPT_VTAB;
+    }
+    pChild = pChild->pParent;
+  }
+  return rc;
+}
+
+static int deleteCell(Rtree *, RtreeNode *, int, int);
+
+static int removeNode(Rtree *pRtree, RtreeNode *pNode, int iHeight){
+  int rc;
+  int rc2;
+  RtreeNode *pParent = 0;
+  int iCell;
+
+  assert( pNode->nRef==1 );
+
+  /* Remove the entry in the parent cell. */
+  rc = nodeParentIndex(pRtree, pNode, &iCell);
+  if( rc==SQLITE_OK ){
+    pParent = pNode->pParent;
+    pNode->pParent = 0;
+    rc = deleteCell(pRtree, pParent, iCell, iHeight+1);
+    testcase( rc!=SQLITE_OK );
+  }
+  rc2 = nodeRelease(pRtree, pParent);
+  if( rc==SQLITE_OK ){
+    rc = rc2;
+  }
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  /* Remove the xxx_node entry. */
+  sqlite3_bind_int64(pRtree->pDeleteNode, 1, pNode->iNode);
+  sqlite3_step(pRtree->pDeleteNode);
+  if( SQLITE_OK!=(rc = sqlite3_reset(pRtree->pDeleteNode)) ){
+    return rc;
+  }
+
+  /* Remove the xxx_parent entry. */
+  sqlite3_bind_int64(pRtree->pDeleteParent, 1, pNode->iNode);
+  sqlite3_step(pRtree->pDeleteParent);
+  if( SQLITE_OK!=(rc = sqlite3_reset(pRtree->pDeleteParent)) ){
+    return rc;
+  }
+
+  /* Remove the node from the in-memory hash table and link it into
+  ** the Rtree.pDeleted list. Its contents will be re-inserted later on.
+  */
+  nodeHashDelete(pRtree, pNode);
+  pNode->iNode = iHeight;
+  pNode->pNext = pRtree->pDeleted;
+  pNode->nRef++;
+  pRtree->pDeleted = pNode;
+
+  return SQLITE_OK;
+}
+
+static int fixBoundingBox(Rtree *pRtree, RtreeNode *pNode){
+  RtreeNode *pParent = pNode->pParent;
+  int rc = SQLITE_OK;
+  if( pParent ){
+    int ii;
+    int nCell = NCELL(pNode);
+    RtreeCell box;                            /* Bounding box for pNode */
+    nodeGetCell(pRtree, pNode, 0, &box);
+    for(ii=1; ii<nCell; ii++){
+      RtreeCell cell;
+      nodeGetCell(pRtree, pNode, ii, &cell);
+      cellUnion(pRtree, &box, &cell);
+    }
+    box.iRowid = pNode->iNode;
+    rc = nodeParentIndex(pRtree, pNode, &ii);
+    if( rc==SQLITE_OK ){
+      nodeOverwriteCell(pRtree, pParent, &box, ii);
+      rc = fixBoundingBox(pRtree, pParent);
+    }
+  }
+  return rc;
+}
+
+/*
+** Delete the cell at index iCell of node pNode. After removing the
+** cell, adjust the r-tree data structure if required.
+*/
+static int deleteCell(Rtree *pRtree, RtreeNode *pNode, int iCell, int iHeight){
+  RtreeNode *pParent;
+  int rc;
+
+  if( SQLITE_OK!=(rc = fixLeafParent(pRtree, pNode)) ){
+    return rc;
+  }
+
+  /* Remove the cell from the node. This call just moves bytes around
+  ** the in-memory node image, so it cannot fail.
+  */
+  nodeDeleteCell(pRtree, pNode, iCell);
+
+  /* If the node is not the tree root and now has less than the minimum
+  ** number of cells, remove it from the tree. Otherwise, update the
+  ** cell in the parent node so that it tightly contains the updated
+  ** node.
+  */
+  pParent = pNode->pParent;
+  assert( pParent || pNode->iNode==1 );
+  if( pParent ){
+    if( NCELL(pNode)<RTREE_MINCELLS(pRtree) ){
+      rc = removeNode(pRtree, pNode, iHeight);
+    }else{
+      rc = fixBoundingBox(pRtree, pNode);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Insert cell pCell into node pNode. Node pNode is the head of a
+** subtree iHeight high (leaf nodes have iHeight==0).
+*/
+static int rtreeInsertCell(
+  Rtree *pRtree,
+  RtreeNode *pNode,
+  RtreeCell *pCell,
+  int iHeight
+){
+  int rc = SQLITE_OK;
+  if( iHeight>0 ){
+    RtreeNode *pChild = nodeHashLookup(pRtree, pCell->iRowid);
+    if( pChild ){
+      nodeRelease(pRtree, pChild->pParent);
+      nodeReference(pNode);
+      pChild->pParent = pNode;
+    }
+  }
+  if( nodeInsertCell(pRtree, pNode, pCell) ){
+    rc = SplitNode(pRtree, pNode, pCell, iHeight);
+  }else{
+    rc = AdjustTree(pRtree, pNode, pCell);
+    if( ALWAYS(rc==SQLITE_OK) ){
+      if( iHeight==0 ){
+        rc = rowidWrite(pRtree, pCell->iRowid, pNode->iNode);
+      }else{
+        rc = parentWrite(pRtree, pCell->iRowid, pNode->iNode);
+      }
+    }
+  }
+  return rc;
+}
+
+static int reinsertNodeContent(Rtree *pRtree, RtreeNode *pNode){
+  int ii;
+  int rc = SQLITE_OK;
+  int nCell = NCELL(pNode);
+
+  for(ii=0; rc==SQLITE_OK && ii<nCell; ii++){
+    RtreeNode *pInsert;
+    RtreeCell cell;
+    nodeGetCell(pRtree, pNode, ii, &cell);
+
+    /* Find a node to store this cell in. pNode->iNode currently contains
+    ** the height of the sub-tree headed by the cell.
+    */
+    rc = ChooseLeaf(pRtree, &cell, (int)pNode->iNode, &pInsert);
+    if( rc==SQLITE_OK ){
+      int rc2;
+      rc = rtreeInsertCell(pRtree, pInsert, &cell, (int)pNode->iNode);
+      rc2 = nodeRelease(pRtree, pInsert);
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Select a currently unused rowid for a new r-tree record.
+*/
+static int rtreeNewRowid(Rtree *pRtree, i64 *piRowid){
+  int rc;
+  sqlite3_bind_null(pRtree->pWriteRowid, 1);
+  sqlite3_bind_null(pRtree->pWriteRowid, 2);
+  sqlite3_step(pRtree->pWriteRowid);
+  rc = sqlite3_reset(pRtree->pWriteRowid);
+  *piRowid = sqlite3_last_insert_rowid(pRtree->db);
+  return rc;
+}
+
+/*
+** Remove the entry with rowid=iDelete from the r-tree structure.
+*/
+static int rtreeDeleteRowid(Rtree *pRtree, sqlite3_int64 iDelete){
+  int rc;                         /* Return code */
+  RtreeNode *pLeaf = 0;           /* Leaf node containing record iDelete */
+  int iCell;                      /* Index of iDelete cell in pLeaf */
+  RtreeNode *pRoot = 0;           /* Root node of rtree structure */
+
+
+  /* Obtain a reference to the root node to initialize Rtree.iDepth */
+  rc = nodeAcquire(pRtree, 1, 0, &pRoot);
+
+  /* Obtain a reference to the leaf node that contains the entry
+  ** about to be deleted.
+  */
+  if( rc==SQLITE_OK ){
+    rc = findLeafNode(pRtree, iDelete, &pLeaf, 0);
+  }
+
+#ifdef CORRUPT_DB
+  assert( pLeaf!=0 || rc!=SQLITE_OK || CORRUPT_DB );
+#endif
+
+  /* Delete the cell in question from the leaf node. */
+  if( rc==SQLITE_OK && pLeaf ){
+    int rc2;
+    rc = nodeRowidIndex(pRtree, pLeaf, iDelete, &iCell);
+    if( rc==SQLITE_OK ){
+      rc = deleteCell(pRtree, pLeaf, iCell, 0);
+    }
+    rc2 = nodeRelease(pRtree, pLeaf);
+    if( rc==SQLITE_OK ){
+      rc = rc2;
+    }
+  }
+
+  /* Delete the corresponding entry in the <rtree>_rowid table. */
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pRtree->pDeleteRowid, 1, iDelete);
+    sqlite3_step(pRtree->pDeleteRowid);
+    rc = sqlite3_reset(pRtree->pDeleteRowid);
+  }
+
+  /* Check if the root node now has exactly one child. If so, remove
+  ** it, schedule the contents of the child for reinsertion and
+  ** reduce the tree height by one.
+  **
+  ** This is equivalent to copying the contents of the child into
+  ** the root node (the operation that Gutman's paper says to perform
+  ** in this scenario).
+  */
+  if( rc==SQLITE_OK && pRtree->iDepth>0 && NCELL(pRoot)==1 ){
+    int rc2;
+    RtreeNode *pChild = 0;
+    i64 iChild = nodeGetRowid(pRtree, pRoot, 0);
+    rc = nodeAcquire(pRtree, iChild, pRoot, &pChild);  /* tag-20210916a */
+    if( rc==SQLITE_OK ){
+      rc = removeNode(pRtree, pChild, pRtree->iDepth-1);
+    }
+    rc2 = nodeRelease(pRtree, pChild);
+    if( rc==SQLITE_OK ) rc = rc2;
+    if( rc==SQLITE_OK ){
+      pRtree->iDepth--;
+      writeInt16(pRoot->zData, pRtree->iDepth);
+      pRoot->isDirty = 1;
+    }
+  }
+
+  /* Re-insert the contents of any underfull nodes removed from the tree. */
+  for(pLeaf=pRtree->pDeleted; pLeaf; pLeaf=pRtree->pDeleted){
+    if( rc==SQLITE_OK ){
+      rc = reinsertNodeContent(pRtree, pLeaf);
+    }
+    pRtree->pDeleted = pLeaf->pNext;
+    pRtree->nNodeRef--;
+    sqlite3_free(pLeaf);
+  }
+
+  /* Release the reference to the root node. */
+  if( rc==SQLITE_OK ){
+    rc = nodeRelease(pRtree, pRoot);
+  }else{
+    nodeRelease(pRtree, pRoot);
+  }
+
+  return rc;
+}
+
+/*
+** Rounding constants for float->double conversion.
+*/
+#define RNDTOWARDS  (1.0 - 1.0/8388608.0)  /* Round towards zero */
+#define RNDAWAY     (1.0 + 1.0/8388608.0)  /* Round away from zero */
+
+#if !defined(SQLITE_RTREE_INT_ONLY)
+/*
+** Convert an sqlite3_value into an RtreeValue (presumably a float)
+** while taking care to round toward negative or positive, respectively.
+*/
+static RtreeValue rtreeValueDown(sqlite3_value *v){
+  double d = sqlite3_value_double(v);
+  float f = (float)d;
+  if( f>d ){
+    f = (float)(d*(d<0 ? RNDAWAY : RNDTOWARDS));
+  }
+  return f;
+}
+static RtreeValue rtreeValueUp(sqlite3_value *v){
+  double d = sqlite3_value_double(v);
+  float f = (float)d;
+  if( f<d ){
+    f = (float)(d*(d<0 ? RNDTOWARDS : RNDAWAY));
+  }
+  return f;
+}
+#endif /* !defined(SQLITE_RTREE_INT_ONLY) */
+
+/*
+** A constraint has failed while inserting a row into an rtree table.
+** Assuming no OOM error occurs, this function sets the error message
+** (at pRtree->base.zErrMsg) to an appropriate value and returns
+** SQLITE_CONSTRAINT.
+**
+** Parameter iCol is the index of the leftmost column involved in the
+** constraint failure. If it is 0, then the constraint that failed is
+** the unique constraint on the id column. Otherwise, it is the rtree
+** (c1<=c2) constraint on columns iCol and iCol+1 that has failed.
+**
+** If an OOM occurs, SQLITE_NOMEM is returned instead of SQLITE_CONSTRAINT.
+*/
+static int rtreeConstraintError(Rtree *pRtree, int iCol){
+  sqlite3_stmt *pStmt = 0;
+  char *zSql;
+  int rc;
+
+  assert( iCol==0 || iCol%2 );
+  zSql = sqlite3_mprintf("SELECT * FROM %Q.%Q", pRtree->zDb, pRtree->zName);
+  if( zSql ){
+    rc = sqlite3_prepare_v2(pRtree->db, zSql, -1, &pStmt, 0);
+  }else{
+    rc = SQLITE_NOMEM;
+  }
+  sqlite3_free(zSql);
+
+  if( rc==SQLITE_OK ){
+    if( iCol==0 ){
+      const char *zCol = sqlite3_column_name(pStmt, 0);
+      pRtree->base.zErrMsg = sqlite3_mprintf(
+          "UNIQUE constraint failed: %s.%s", pRtree->zName, zCol
+      );
+    }else{
+      const char *zCol1 = sqlite3_column_name(pStmt, iCol);
+      const char *zCol2 = sqlite3_column_name(pStmt, iCol+1);
+      pRtree->base.zErrMsg = sqlite3_mprintf(
+          "rtree constraint failed: %s.(%s<=%s)", pRtree->zName, zCol1, zCol2
+      );
+    }
+  }
+
+  sqlite3_finalize(pStmt);
+  return (rc==SQLITE_OK ? SQLITE_CONSTRAINT : rc);
+}
+
+
+
+/*
+** The xUpdate method for rtree module virtual tables.
+*/
+static int rtreeUpdate(
+  sqlite3_vtab *pVtab,
+  int nData,
+  sqlite3_value **aData,
+  sqlite_int64 *pRowid
+){
+  Rtree *pRtree = (Rtree *)pVtab;
+  int rc = SQLITE_OK;
+  RtreeCell cell;                 /* New cell to insert if nData>1 */
+  int bHaveRowid = 0;             /* Set to 1 after new rowid is determined */
+
+  if( pRtree->nNodeRef ){
+    /* Unable to write to the btree while another cursor is reading from it,
+    ** since the write might do a rebalance which would disrupt the read
+    ** cursor. */
+    return SQLITE_LOCKED_VTAB;
+  }
+  rtreeReference(pRtree);
+  assert(nData>=1);
+
+  memset(&cell, 0, sizeof(cell));
+
+  /* Constraint handling. A write operation on an r-tree table may return
+  ** SQLITE_CONSTRAINT for two reasons:
+  **
+  **   1. A duplicate rowid value, or
+  **   2. The supplied data violates the "x2>=x1" constraint.
+  **
+  ** In the first case, if the conflict-handling mode is REPLACE, then
+  ** the conflicting row can be removed before proceeding. In the second
+  ** case, SQLITE_CONSTRAINT must be returned regardless of the
+  ** conflict-handling mode specified by the user.
+  */
+  if( nData>1 ){
+    int ii;
+    int nn = nData - 4;
+
+    if( nn > pRtree->nDim2 ) nn = pRtree->nDim2;
+    /* Populate the cell.aCoord[] array. The first coordinate is aData[3].
+    **
+    ** NB: nData can only be less than nDim*2+3 if the rtree is mis-declared
+    ** with "column" that are interpreted as table constraints.
+    ** Example:  CREATE VIRTUAL TABLE bad USING rtree(x,y,CHECK(y>5));
+    ** This problem was discovered after years of use, so we silently ignore
+    ** these kinds of misdeclared tables to avoid breaking any legacy.
+    */
+
+#ifndef SQLITE_RTREE_INT_ONLY
+    if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+      for(ii=0; ii<nn; ii+=2){
+        cell.aCoord[ii].f = rtreeValueDown(aData[ii+3]);
+        cell.aCoord[ii+1].f = rtreeValueUp(aData[ii+4]);
+        if( cell.aCoord[ii].f>cell.aCoord[ii+1].f ){
+          rc = rtreeConstraintError(pRtree, ii+1);
+          goto constraint;
+        }
+      }
+    }else
+#endif
+    {
+      for(ii=0; ii<nn; ii+=2){
+        cell.aCoord[ii].i = sqlite3_value_int(aData[ii+3]);
+        cell.aCoord[ii+1].i = sqlite3_value_int(aData[ii+4]);
+        if( cell.aCoord[ii].i>cell.aCoord[ii+1].i ){
+          rc = rtreeConstraintError(pRtree, ii+1);
+          goto constraint;
+        }
+      }
+    }
+
+    /* If a rowid value was supplied, check if it is already present in
+    ** the table. If so, the constraint has failed. */
+    if( sqlite3_value_type(aData[2])!=SQLITE_NULL ){
+      cell.iRowid = sqlite3_value_int64(aData[2]);
+      if( sqlite3_value_type(aData[0])==SQLITE_NULL
+       || sqlite3_value_int64(aData[0])!=cell.iRowid
+      ){
+        int steprc;
+        sqlite3_bind_int64(pRtree->pReadRowid, 1, cell.iRowid);
+        steprc = sqlite3_step(pRtree->pReadRowid);
+        rc = sqlite3_reset(pRtree->pReadRowid);
+        if( SQLITE_ROW==steprc ){
+          if( sqlite3_vtab_on_conflict(pRtree->db)==SQLITE_REPLACE ){
+            rc = rtreeDeleteRowid(pRtree, cell.iRowid);
+          }else{
+            rc = rtreeConstraintError(pRtree, 0);
+            goto constraint;
+          }
+        }
+      }
+      bHaveRowid = 1;
+    }
+  }
+
+  /* If aData[0] is not an SQL NULL value, it is the rowid of a
+  ** record to delete from the r-tree table. The following block does
+  ** just that.
+  */
+  if( sqlite3_value_type(aData[0])!=SQLITE_NULL ){
+    rc = rtreeDeleteRowid(pRtree, sqlite3_value_int64(aData[0]));
+  }
+
+  /* If the aData[] array contains more than one element, elements
+  ** (aData[2]..aData[argc-1]) contain a new record to insert into
+  ** the r-tree structure.
+  */
+  if( rc==SQLITE_OK && nData>1 ){
+    /* Insert the new record into the r-tree */
+    RtreeNode *pLeaf = 0;
+
+    /* Figure out the rowid of the new row. */
+    if( bHaveRowid==0 ){
+      rc = rtreeNewRowid(pRtree, &cell.iRowid);
+    }
+    *pRowid = cell.iRowid;
+
+    if( rc==SQLITE_OK ){
+      rc = ChooseLeaf(pRtree, &cell, 0, &pLeaf);
+    }
+    if( rc==SQLITE_OK ){
+      int rc2;
+      rc = rtreeInsertCell(pRtree, pLeaf, &cell, 0);
+      rc2 = nodeRelease(pRtree, pLeaf);
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+    if( rc==SQLITE_OK && pRtree->nAux ){
+      sqlite3_stmt *pUp = pRtree->pWriteAux;
+      int jj;
+      sqlite3_bind_int64(pUp, 1, *pRowid);
+      for(jj=0; jj<pRtree->nAux; jj++){
+        sqlite3_bind_value(pUp, jj+2, aData[pRtree->nDim2+3+jj]);
+      }
+      sqlite3_step(pUp);
+      rc = sqlite3_reset(pUp);
+    }
+  }
+
+constraint:
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+/*
+** Called when a transaction starts.
+*/
+static int rtreeBeginTransaction(sqlite3_vtab *pVtab){
+  Rtree *pRtree = (Rtree *)pVtab;
+  assert( pRtree->inWrTrans==0 );
+  pRtree->inWrTrans = 1;
+  return SQLITE_OK;
+}
+
+/*
+** Called when a transaction completes (either by COMMIT or ROLLBACK).
+** The sqlite3_blob object should be released at this point.
+*/
+static int rtreeEndTransaction(sqlite3_vtab *pVtab){
+  Rtree *pRtree = (Rtree *)pVtab;
+  pRtree->inWrTrans = 0;
+  nodeBlobReset(pRtree);
+  return SQLITE_OK;
+}
+static int rtreeRollback(sqlite3_vtab *pVtab){
+  return rtreeEndTransaction(pVtab);
+}
+
+/*
+** The xRename method for rtree module virtual tables.
+*/
+static int rtreeRename(sqlite3_vtab *pVtab, const char *zNewName){
+  Rtree *pRtree = (Rtree *)pVtab;
+  int rc = SQLITE_NOMEM;
+  char *zSql = sqlite3_mprintf(
+    "ALTER TABLE %Q.'%q_node'   RENAME TO \"%w_node\";"
+    "ALTER TABLE %Q.'%q_parent' RENAME TO \"%w_parent\";"
+    "ALTER TABLE %Q.'%q_rowid'  RENAME TO \"%w_rowid\";"
+    , pRtree->zDb, pRtree->zName, zNewName
+    , pRtree->zDb, pRtree->zName, zNewName
+    , pRtree->zDb, pRtree->zName, zNewName
+  );
+  if( zSql ){
+    nodeBlobReset(pRtree);
+    rc = sqlite3_exec(pRtree->db, zSql, 0, 0, 0);
+    sqlite3_free(zSql);
+  }
+  return rc;
+}
+
+/*
+** The xSavepoint method.
+**
+** This module does not need to do anything to support savepoints. However,
+** it uses this hook to close any open blob handle. This is done because a
+** DROP TABLE command - which fortunately always opens a savepoint - cannot
+** succeed if there are any open blob handles. i.e. if the blob handle were
+** not closed here, the following would fail:
+**
+**   BEGIN;
+**     INSERT INTO rtree...
+**     DROP TABLE <tablename>;    -- Would fail with SQLITE_LOCKED
+**   COMMIT;
+*/
+static int rtreeSavepoint(sqlite3_vtab *pVtab, int iSavepoint){
+  Rtree *pRtree = (Rtree *)pVtab;
+  u8 iwt = pRtree->inWrTrans;
+  UNUSED_PARAMETER(iSavepoint);
+  pRtree->inWrTrans = 0;
+  nodeBlobReset(pRtree);
+  pRtree->inWrTrans = iwt;
+  return SQLITE_OK;
+}
+
+/*
+** This function populates the pRtree->nRowEst variable with an estimate
+** of the number of rows in the virtual table. If possible, this is based
+** on sqlite_stat1 data. Otherwise, use RTREE_DEFAULT_ROWEST.
+*/
+static int rtreeQueryStat1(sqlite3 *db, Rtree *pRtree){
+  const char *zFmt = "SELECT stat FROM %Q.sqlite_stat1 WHERE tbl = '%q_rowid'";
+  char *zSql;
+  sqlite3_stmt *p;
+  int rc;
+  i64 nRow = RTREE_MIN_ROWEST;
+
+  rc = sqlite3_table_column_metadata(
+      db, pRtree->zDb, "sqlite_stat1",0,0,0,0,0,0
+  );
+  if( rc!=SQLITE_OK ){
+    pRtree->nRowEst = RTREE_DEFAULT_ROWEST;
+    return rc==SQLITE_ERROR ? SQLITE_OK : rc;
+  }
+  zSql = sqlite3_mprintf(zFmt, pRtree->zDb, pRtree->zName);
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare_v2(db, zSql, -1, &p, 0);
+    if( rc==SQLITE_OK ){
+      if( sqlite3_step(p)==SQLITE_ROW ) nRow = sqlite3_column_int64(p, 0);
+      rc = sqlite3_finalize(p);
+    }
+    sqlite3_free(zSql);
+  }
+  pRtree->nRowEst = MAX(nRow, RTREE_MIN_ROWEST);
+  return rc;
+}
+
+
+/*
+** Return true if zName is the extension on one of the shadow tables used
+** by this module.
+*/
+static int rtreeShadowName(const char *zName){
+  static const char *azName[] = {
+    "node", "parent", "rowid"
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
+    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
+  }
+  return 0;
+}
+
+/* Forward declaration */
+static int rtreeIntegrity(sqlite3_vtab*, const char*, const char*, int, char**);
+
+static sqlite3_module rtreeModule = {
+  4,                          /* iVersion */
+  rtreeCreate,                /* xCreate - create a table */
+  rtreeConnect,               /* xConnect - connect to an existing table */
+  rtreeBestIndex,             /* xBestIndex - Determine search strategy */
+  rtreeDisconnect,            /* xDisconnect - Disconnect from a table */
+  rtreeDestroy,               /* xDestroy - Drop a table */
+  rtreeOpen,                  /* xOpen - open a cursor */
+  rtreeClose,                 /* xClose - close a cursor */
+  rtreeFilter,                /* xFilter - configure scan constraints */
+  rtreeNext,                  /* xNext - advance a cursor */
+  rtreeEof,                   /* xEof */
+  rtreeColumn,                /* xColumn - read data */
+  rtreeRowid,                 /* xRowid - read data */
+  rtreeUpdate,                /* xUpdate - write data */
+  rtreeBeginTransaction,      /* xBegin - begin transaction */
+  rtreeEndTransaction,        /* xSync - sync transaction */
+  rtreeEndTransaction,        /* xCommit - commit transaction */
+  rtreeRollback,              /* xRollback - rollback transaction */
+  0,                          /* xFindFunction - function overloading */
+  rtreeRename,                /* xRename - rename the table */
+  rtreeSavepoint,             /* xSavepoint */
+  0,                          /* xRelease */
+  0,                          /* xRollbackTo */
+  rtreeShadowName,            /* xShadowName */
+  rtreeIntegrity              /* xIntegrity */
+};
+
+static int rtreeSqlInit(
+  Rtree *pRtree,
+  sqlite3 *db,
+  const char *zDb,
+  const char *zPrefix,
+  int isCreate
+){
+  int rc = SQLITE_OK;
+
+  #define N_STATEMENT 8
+  static const char *azSql[N_STATEMENT] = {
+    /* Write the xxx_node table */
+    "INSERT OR REPLACE INTO '%q'.'%q_node' VALUES(?1, ?2)",
+    "DELETE FROM '%q'.'%q_node' WHERE nodeno = ?1",
+
+    /* Read and write the xxx_rowid table */
+    "SELECT nodeno FROM '%q'.'%q_rowid' WHERE rowid = ?1",
+    "INSERT OR REPLACE INTO '%q'.'%q_rowid' VALUES(?1, ?2)",
+    "DELETE FROM '%q'.'%q_rowid' WHERE rowid = ?1",
+
+    /* Read and write the xxx_parent table */
+    "SELECT parentnode FROM '%q'.'%q_parent' WHERE nodeno = ?1",
+    "INSERT OR REPLACE INTO '%q'.'%q_parent' VALUES(?1, ?2)",
+    "DELETE FROM '%q'.'%q_parent' WHERE nodeno = ?1"
+  };
+  sqlite3_stmt **appStmt[N_STATEMENT];
+  int i;
+  const int f = SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB;
+
+  pRtree->db = db;
+
+  if( isCreate ){
+    char *zCreate;
+    sqlite3_str *p = sqlite3_str_new(db);
+    int ii;
+    sqlite3_str_appendf(p,
+       "CREATE TABLE \"%w\".\"%w_rowid\"(rowid INTEGER PRIMARY KEY,nodeno",
+       zDb, zPrefix);
+    for(ii=0; ii<pRtree->nAux; ii++){
+      sqlite3_str_appendf(p,",a%d",ii);
+    }
+    sqlite3_str_appendf(p,
+      ");CREATE TABLE \"%w\".\"%w_node\"(nodeno INTEGER PRIMARY KEY,data);",
+      zDb, zPrefix);
+    sqlite3_str_appendf(p,
+    "CREATE TABLE \"%w\".\"%w_parent\"(nodeno INTEGER PRIMARY KEY,parentnode);",
+      zDb, zPrefix);
+    sqlite3_str_appendf(p,
+       "INSERT INTO \"%w\".\"%w_node\"VALUES(1,zeroblob(%d))",
+       zDb, zPrefix, pRtree->iNodeSize);
+    zCreate = sqlite3_str_finish(p);
+    if( !zCreate ){
+      return SQLITE_NOMEM;
+    }
+    rc = sqlite3_exec(db, zCreate, 0, 0, 0);
+    sqlite3_free(zCreate);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+  }
+
+  appStmt[0] = &pRtree->pWriteNode;
+  appStmt[1] = &pRtree->pDeleteNode;
+  appStmt[2] = &pRtree->pReadRowid;
+  appStmt[3] = &pRtree->pWriteRowid;
+  appStmt[4] = &pRtree->pDeleteRowid;
+  appStmt[5] = &pRtree->pReadParent;
+  appStmt[6] = &pRtree->pWriteParent;
+  appStmt[7] = &pRtree->pDeleteParent;
+
+  rc = rtreeQueryStat1(db, pRtree);
+  for(i=0; i<N_STATEMENT && rc==SQLITE_OK; i++){
+    char *zSql;
+    const char *zFormat;
+    if( i!=3 || pRtree->nAux==0 ){
+       zFormat = azSql[i];
+    }else {
+       /* An UPSERT is very slightly slower than REPLACE, but it is needed
+       ** if there are auxiliary columns */
+       zFormat = "INSERT INTO\"%w\".\"%w_rowid\"(rowid,nodeno)VALUES(?1,?2)"
+                  "ON CONFLICT(rowid)DO UPDATE SET nodeno=excluded.nodeno";
+    }
+    zSql = sqlite3_mprintf(zFormat, zDb, zPrefix);
+    if( zSql ){
+      rc = sqlite3_prepare_v3(db, zSql, -1, f, appStmt[i], 0);
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+    sqlite3_free(zSql);
+  }
+  if( pRtree->nAux && rc!=SQLITE_NOMEM ){
+    pRtree->zReadAuxSql = sqlite3_mprintf(
+       "SELECT * FROM \"%w\".\"%w_rowid\" WHERE rowid=?1",
+       zDb, zPrefix);
+    if( pRtree->zReadAuxSql==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      sqlite3_str *p = sqlite3_str_new(db);
+      int ii;
+      char *zSql;
+      sqlite3_str_appendf(p, "UPDATE \"%w\".\"%w_rowid\"SET ", zDb, zPrefix);
+      for(ii=0; ii<pRtree->nAux; ii++){
+        if( ii ) sqlite3_str_append(p, ",", 1);
+#ifdef SQLITE_ENABLE_GEOPOLY
+        if( ii<pRtree->nAuxNotNull ){
+          sqlite3_str_appendf(p,"a%d=coalesce(?%d,a%d)",ii,ii+2,ii);
+        }else
+#endif
+        {
+          sqlite3_str_appendf(p,"a%d=?%d",ii,ii+2);
+        }
+      }
+      sqlite3_str_appendf(p, " WHERE rowid=?1");
+      zSql = sqlite3_str_finish(p);
+      if( zSql==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        rc = sqlite3_prepare_v3(db, zSql, -1, f, &pRtree->pWriteAux, 0);
+        sqlite3_free(zSql);
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The second argument to this function contains the text of an SQL statement
+** that returns a single integer value. The statement is compiled and executed
+** using database connection db. If successful, the integer value returned
+** is written to *piVal and SQLITE_OK returned. Otherwise, an SQLite error
+** code is returned and the value of *piVal after returning is not defined.
+*/
+static int getIntFromStmt(sqlite3 *db, const char *zSql, int *piVal){
+  int rc = SQLITE_NOMEM;
+  if( zSql ){
+    sqlite3_stmt *pStmt = 0;
+    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        *piVal = sqlite3_column_int(pStmt, 0);
+      }
+      rc = sqlite3_finalize(pStmt);
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is called from within the xConnect() or xCreate() method to
+** determine the node-size used by the rtree table being created or connected
+** to. If successful, pRtree->iNodeSize is populated and SQLITE_OK returned.
+** Otherwise, an SQLite error code is returned.
+**
+** If this function is being called as part of an xConnect(), then the rtree
+** table already exists. In this case the node-size is determined by inspecting
+** the root node of the tree.
+**
+** Otherwise, for an xCreate(), use 64 bytes less than the database page-size.
+** This ensures that each node is stored on a single database page. If the
+** database page-size is so large that more than RTREE_MAXCELLS entries
+** would fit in a single node, use a smaller node-size.
+*/
+static int getNodeSize(
+  sqlite3 *db,                    /* Database handle */
+  Rtree *pRtree,                  /* Rtree handle */
+  int isCreate,                   /* True for xCreate, false for xConnect */
+  char **pzErr                    /* OUT: Error message, if any */
+){
+  int rc;
+  char *zSql;
+  if( isCreate ){
+    int iPageSize = 0;
+    zSql = sqlite3_mprintf("PRAGMA %Q.page_size", pRtree->zDb);
+    rc = getIntFromStmt(db, zSql, &iPageSize);
+    if( rc==SQLITE_OK ){
+      pRtree->iNodeSize = iPageSize-64;
+      if( (4+pRtree->nBytesPerCell*RTREE_MAXCELLS)<pRtree->iNodeSize ){
+        pRtree->iNodeSize = 4+pRtree->nBytesPerCell*RTREE_MAXCELLS;
+      }
+    }else{
+      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    }
+  }else{
+    zSql = sqlite3_mprintf(
+        "SELECT length(data) FROM '%q'.'%q_node' WHERE nodeno = 1",
+        pRtree->zDb, pRtree->zName
+    );
+    rc = getIntFromStmt(db, zSql, &pRtree->iNodeSize);
+    if( rc!=SQLITE_OK ){
+      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    }else if( pRtree->iNodeSize<(512-64) ){
+      rc = SQLITE_CORRUPT_VTAB;
+      RTREE_IS_CORRUPT(pRtree);
+      *pzErr = sqlite3_mprintf("undersize RTree blobs in \"%q_node\"",
+                               pRtree->zName);
+    }
+  }
+
+  sqlite3_free(zSql);
+  return rc;
+}
+
+/*
+** Return the length of a token
+*/
+static int rtreeTokenLength(const char *z){
+  int dummy = 0;
+  return sqlite3GetToken((const unsigned char*)z,&dummy);
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the r-tree virtual table.
+**
+**   argv[0]   -> module name
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> column names...
+*/
+static int rtreeInit(
+  sqlite3 *db,                        /* Database connection */
+  void *pAux,                         /* One of the RTREE_COORD_* constants */
+  int argc, const char *const*argv,   /* Parameters to CREATE TABLE statement */
+  sqlite3_vtab **ppVtab,              /* OUT: New virtual table */
+  char **pzErr,                       /* OUT: Error message, if any */
+  int isCreate                        /* True for xCreate, false for xConnect */
+){
+  int rc = SQLITE_OK;
+  Rtree *pRtree;
+  int nDb;              /* Length of string argv[1] */
+  int nName;            /* Length of string argv[2] */
+  int eCoordType = (pAux ? RTREE_COORD_INT32 : RTREE_COORD_REAL32);
+  sqlite3_str *pSql;
+  char *zSql;
+  int ii = 4;
+  int iErr;
+
+  const char *aErrMsg[] = {
+    0,                                                    /* 0 */
+    "Wrong number of columns for an rtree table",         /* 1 */
+    "Too few columns for an rtree table",                 /* 2 */
+    "Too many columns for an rtree table",                /* 3 */
+    "Auxiliary rtree columns must be last"                /* 4 */
+  };
+
+  assert( RTREE_MAX_AUX_COLUMN<256 ); /* Aux columns counted by a u8 */
+  if( argc<6 || argc>RTREE_MAX_AUX_COLUMN+3 ){
+    *pzErr = sqlite3_mprintf("%s", aErrMsg[2 + (argc>=6)]);
+    return SQLITE_ERROR;
+  }
+
+  sqlite3_vtab_config(db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1);
+  sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
+
+
+  /* Allocate the sqlite3_vtab structure */
+  nDb = (int)strlen(argv[1]);
+  nName = (int)strlen(argv[2]);
+  pRtree = (Rtree *)sqlite3_malloc64(sizeof(Rtree)+nDb+nName*2+8);
+  if( !pRtree ){
+    return SQLITE_NOMEM;
+  }
+  memset(pRtree, 0, sizeof(Rtree)+nDb+nName*2+8);
+  pRtree->nBusy = 1;
+  pRtree->base.pModule = &rtreeModule;
+  pRtree->zDb = (char *)&pRtree[1];
+  pRtree->zName = &pRtree->zDb[nDb+1];
+  pRtree->zNodeName = &pRtree->zName[nName+1];
+  pRtree->eCoordType = (u8)eCoordType;
+  memcpy(pRtree->zDb, argv[1], nDb);
+  memcpy(pRtree->zName, argv[2], nName);
+  memcpy(pRtree->zNodeName, argv[2], nName);
+  memcpy(&pRtree->zNodeName[nName], "_node", 6);
+
+
+  /* Create/Connect to the underlying relational database schema. If
+  ** that is successful, call sqlite3_declare_vtab() to configure
+  ** the r-tree table schema.
+  */
+  pSql = sqlite3_str_new(db);
+  sqlite3_str_appendf(pSql, "CREATE TABLE x(%.*s INT",
+                      rtreeTokenLength(argv[3]), argv[3]);
+  for(ii=4; ii<argc; ii++){
+    const char *zArg = argv[ii];
+    if( zArg[0]=='+' ){
+      pRtree->nAux++;
+      sqlite3_str_appendf(pSql, ",%.*s", rtreeTokenLength(zArg+1), zArg+1);
+    }else if( pRtree->nAux>0 ){
+      break;
+    }else{
+      static const char *azFormat[] = {",%.*s REAL", ",%.*s INT"};
+      pRtree->nDim2++;
+      sqlite3_str_appendf(pSql, azFormat[eCoordType],
+                          rtreeTokenLength(zArg), zArg);
+    }
+  }
+  sqlite3_str_appendf(pSql, ");");
+  zSql = sqlite3_str_finish(pSql);
+  if( !zSql ){
+    rc = SQLITE_NOMEM;
+  }else if( ii<argc ){
+    *pzErr = sqlite3_mprintf("%s", aErrMsg[4]);
+    rc = SQLITE_ERROR;
+  }else if( SQLITE_OK!=(rc = sqlite3_declare_vtab(db, zSql)) ){
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+  }
+  sqlite3_free(zSql);
+  if( rc ) goto rtreeInit_fail;
+  pRtree->nDim = pRtree->nDim2/2;
+  if( pRtree->nDim<1 ){
+    iErr = 2;
+  }else if( pRtree->nDim2>RTREE_MAX_DIMENSIONS*2 ){
+    iErr = 3;
+  }else if( pRtree->nDim2 % 2 ){
+    iErr = 1;
+  }else{
+    iErr = 0;
+  }
+  if( iErr ){
+    *pzErr = sqlite3_mprintf("%s", aErrMsg[iErr]);
+    goto rtreeInit_fail;
+  }
+  pRtree->nBytesPerCell = 8 + pRtree->nDim2*4;
+
+  /* Figure out the node size to use. */
+  rc = getNodeSize(db, pRtree, isCreate, pzErr);
+  if( rc ) goto rtreeInit_fail;
+  rc = rtreeSqlInit(pRtree, db, argv[1], argv[2], isCreate);
+  if( rc ){
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    goto rtreeInit_fail;
+  }
+
+  *ppVtab = (sqlite3_vtab *)pRtree;
+  return SQLITE_OK;
+
+rtreeInit_fail:
+  if( rc==SQLITE_OK ) rc = SQLITE_ERROR;
+  assert( *ppVtab==0 );
+  assert( pRtree->nBusy==1 );
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+
+/*
+** Implementation of a scalar function that decodes r-tree nodes to
+** human readable strings. This can be used for debugging and analysis.
+**
+** The scalar function takes two arguments: (1) the number of dimensions
+** to the rtree (between 1 and 5, inclusive) and (2) a blob of data containing
+** an r-tree node.  For a two-dimensional r-tree structure called "rt", to
+** deserialize all nodes, a statement like:
+**
+**   SELECT rtreenode(2, data) FROM rt_node;
+**
+** The human readable string takes the form of a Tcl list with one
+** entry for each cell in the r-tree node. Each entry is itself a
+** list, containing the 8-byte rowid/pageno followed by the
+** <num-dimension>*2 coordinates.
+*/
+static void rtreenode(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
+  RtreeNode node;
+  Rtree tree;
+  int ii;
+  int nData;
+  int errCode;
+  sqlite3_str *pOut;
+
+  UNUSED_PARAMETER(nArg);
+  memset(&node, 0, sizeof(RtreeNode));
+  memset(&tree, 0, sizeof(Rtree));
+  tree.nDim = (u8)sqlite3_value_int(apArg[0]);
+  if( tree.nDim<1 || tree.nDim>5 ) return;
+  tree.nDim2 = tree.nDim*2;
+  tree.nBytesPerCell = 8 + 8 * tree.nDim;
+  node.zData = (u8 *)sqlite3_value_blob(apArg[1]);
+  if( node.zData==0 ) return;
+  nData = sqlite3_value_bytes(apArg[1]);
+  if( nData<4 ) return;
+  if( nData<NCELL(&node)*tree.nBytesPerCell ) return;
+
+  pOut = sqlite3_str_new(0);
+  for(ii=0; ii<NCELL(&node); ii++){
+    RtreeCell cell;
+    int jj;
+
+    nodeGetCell(&tree, &node, ii, &cell);
+    if( ii>0 ) sqlite3_str_append(pOut, " ", 1);
+    sqlite3_str_appendf(pOut, "{%lld", cell.iRowid);
+    for(jj=0; jj<tree.nDim2; jj++){
+#ifndef SQLITE_RTREE_INT_ONLY
+      sqlite3_str_appendf(pOut, " %g", (double)cell.aCoord[jj].f);
+#else
+      sqlite3_str_appendf(pOut, " %d", cell.aCoord[jj].i);
+#endif
+    }
+    sqlite3_str_append(pOut, "}", 1);
+  }
+  errCode = sqlite3_str_errcode(pOut);
+  sqlite3_result_error_code(ctx, errCode);
+  sqlite3_result_text(ctx, sqlite3_str_finish(pOut), -1, sqlite3_free);
+}
+
+/* This routine implements an SQL function that returns the "depth" parameter
+** from the front of a blob that is an r-tree node.  For example:
+**
+**     SELECT rtreedepth(data) FROM rt_node WHERE nodeno=1;
+**
+** The depth value is 0 for all nodes other than the root node, and the root
+** node always has nodeno=1, so the example above is the primary use for this
+** routine.  This routine is intended for testing and analysis only.
+*/
+static void rtreedepth(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
+  UNUSED_PARAMETER(nArg);
+  if( sqlite3_value_type(apArg[0])!=SQLITE_BLOB
+   || sqlite3_value_bytes(apArg[0])<2
+
+  ){
+    sqlite3_result_error(ctx, "Invalid argument to rtreedepth()", -1);
+  }else{
+    u8 *zBlob = (u8 *)sqlite3_value_blob(apArg[0]);
+    if( zBlob ){
+      sqlite3_result_int(ctx, readInt16(zBlob));
+    }else{
+      sqlite3_result_error_nomem(ctx);
+    }
+  }
+}
+
+/*
+** Context object passed between the various routines that make up the
+** implementation of integrity-check function rtreecheck().
+*/
+typedef struct RtreeCheck RtreeCheck;
+struct RtreeCheck {
+  sqlite3 *db;                    /* Database handle */
+  const char *zDb;                /* Database containing rtree table */
+  const char *zTab;               /* Name of rtree table */
+  int bInt;                       /* True for rtree_i32 table */
+  int nDim;                       /* Number of dimensions for this rtree tbl */
+  sqlite3_stmt *pGetNode;         /* Statement used to retrieve nodes */
+  sqlite3_stmt *aCheckMapping[2]; /* Statements to query %_parent/%_rowid */
+  int nLeaf;                      /* Number of leaf cells in table */
+  int nNonLeaf;                   /* Number of non-leaf cells in table */
+  int rc;                         /* Return code */
+  char *zReport;                  /* Message to report */
+  int nErr;                       /* Number of lines in zReport */
+};
+
+#define RTREE_CHECK_MAX_ERROR 100
+
+/*
+** Reset SQL statement pStmt. If the sqlite3_reset() call returns an error,
+** and RtreeCheck.rc==SQLITE_OK, set RtreeCheck.rc to the error code.
+*/
+static void rtreeCheckReset(RtreeCheck *pCheck, sqlite3_stmt *pStmt){
+  int rc = sqlite3_reset(pStmt);
+  if( pCheck->rc==SQLITE_OK ) pCheck->rc = rc;
+}
+
+/*
+** The second and subsequent arguments to this function are a format string
+** and printf style arguments. This function formats the string and attempts
+** to compile it as an SQL statement.
+**
+** If successful, a pointer to the new SQL statement is returned. Otherwise,
+** NULL is returned and an error code left in RtreeCheck.rc.
+*/
+static sqlite3_stmt *rtreeCheckPrepare(
+  RtreeCheck *pCheck,             /* RtreeCheck object */
+  const char *zFmt, ...           /* Format string and trailing args */
+){
+  va_list ap;
+  char *z;
+  sqlite3_stmt *pRet = 0;
+
+  va_start(ap, zFmt);
+  z = sqlite3_vmprintf(zFmt, ap);
+
+  if( pCheck->rc==SQLITE_OK ){
+    if( z==0 ){
+      pCheck->rc = SQLITE_NOMEM;
+    }else{
+      pCheck->rc = sqlite3_prepare_v2(pCheck->db, z, -1, &pRet, 0);
+    }
+  }
+
+  sqlite3_free(z);
+  va_end(ap);
+  return pRet;
+}
+
+/*
+** The second and subsequent arguments to this function are a printf()
+** style format string and arguments. This function formats the string and
+** appends it to the report being accumuated in pCheck.
+*/
+static void rtreeCheckAppendMsg(RtreeCheck *pCheck, const char *zFmt, ...){
+  va_list ap;
+  va_start(ap, zFmt);
+  if( pCheck->rc==SQLITE_OK && pCheck->nErr<RTREE_CHECK_MAX_ERROR ){
+    char *z = sqlite3_vmprintf(zFmt, ap);
+    if( z==0 ){
+      pCheck->rc = SQLITE_NOMEM;
+    }else{
+      pCheck->zReport = sqlite3_mprintf("%z%s%z",
+          pCheck->zReport, (pCheck->zReport ? "\n" : ""), z
+      );
+      if( pCheck->zReport==0 ){
+        pCheck->rc = SQLITE_NOMEM;
+      }
+    }
+    pCheck->nErr++;
+  }
+  va_end(ap);
+}
+
+/*
+** This function is a no-op if there is already an error code stored
+** in the RtreeCheck object indicated by the first argument. NULL is
+** returned in this case.
+**
+** Otherwise, the contents of rtree table node iNode are loaded from
+** the database and copied into a buffer obtained from sqlite3_malloc().
+** If no error occurs, a pointer to the buffer is returned and (*pnNode)
+** is set to the size of the buffer in bytes.
+**
+** Or, if an error does occur, NULL is returned and an error code left
+** in the RtreeCheck object. The final value of *pnNode is undefined in
+** this case.
+*/
+static u8 *rtreeCheckGetNode(RtreeCheck *pCheck, i64 iNode, int *pnNode){
+  u8 *pRet = 0;                   /* Return value */
+
+  if( pCheck->rc==SQLITE_OK && pCheck->pGetNode==0 ){
+    pCheck->pGetNode = rtreeCheckPrepare(pCheck,
+        "SELECT data FROM %Q.'%q_node' WHERE nodeno=?",
+        pCheck->zDb, pCheck->zTab
+    );
+  }
+
+  if( pCheck->rc==SQLITE_OK ){
+    sqlite3_bind_int64(pCheck->pGetNode, 1, iNode);
+    if( sqlite3_step(pCheck->pGetNode)==SQLITE_ROW ){
+      int nNode = sqlite3_column_bytes(pCheck->pGetNode, 0);
+      const u8 *pNode = (const u8*)sqlite3_column_blob(pCheck->pGetNode, 0);
+      pRet = sqlite3_malloc64(nNode);
+      if( pRet==0 ){
+        pCheck->rc = SQLITE_NOMEM;
+      }else{
+        memcpy(pRet, pNode, nNode);
+        *pnNode = nNode;
+      }
+    }
+    rtreeCheckReset(pCheck, pCheck->pGetNode);
+    if( pCheck->rc==SQLITE_OK && pRet==0 ){
+      rtreeCheckAppendMsg(pCheck, "Node %lld missing from database", iNode);
+    }
+  }
+
+  return pRet;
+}
+
+/*
+** This function is used to check that the %_parent (if bLeaf==0) or %_rowid
+** (if bLeaf==1) table contains a specified entry. The schemas of the
+** two tables are:
+**
+**   CREATE TABLE %_parent(nodeno INTEGER PRIMARY KEY, parentnode INTEGER)
+**   CREATE TABLE %_rowid(rowid INTEGER PRIMARY KEY, nodeno INTEGER, ...)
+**
+** In both cases, this function checks that there exists an entry with
+** IPK value iKey and the second column set to iVal.
+**
+*/
+static void rtreeCheckMapping(
+  RtreeCheck *pCheck,             /* RtreeCheck object */
+  int bLeaf,                      /* True for a leaf cell, false for interior */
+  i64 iKey,                       /* Key for mapping */
+  i64 iVal                        /* Expected value for mapping */
+){
+  int rc;
+  sqlite3_stmt *pStmt;
+  const char *azSql[2] = {
+    "SELECT parentnode FROM %Q.'%q_parent' WHERE nodeno=?1",
+    "SELECT nodeno FROM %Q.'%q_rowid' WHERE rowid=?1"
+  };
+
+  assert( bLeaf==0 || bLeaf==1 );
+  if( pCheck->aCheckMapping[bLeaf]==0 ){
+    pCheck->aCheckMapping[bLeaf] = rtreeCheckPrepare(pCheck,
+        azSql[bLeaf], pCheck->zDb, pCheck->zTab
+    );
+  }
+  if( pCheck->rc!=SQLITE_OK ) return;
+
+  pStmt = pCheck->aCheckMapping[bLeaf];
+  sqlite3_bind_int64(pStmt, 1, iKey);
+  rc = sqlite3_step(pStmt);
+  if( rc==SQLITE_DONE ){
+    rtreeCheckAppendMsg(pCheck, "Mapping (%lld -> %lld) missing from %s table",
+        iKey, iVal, (bLeaf ? "%_rowid" : "%_parent")
+    );
+  }else if( rc==SQLITE_ROW ){
+    i64 ii = sqlite3_column_int64(pStmt, 0);
+    if( ii!=iVal ){
+      rtreeCheckAppendMsg(pCheck,
+          "Found (%lld -> %lld) in %s table, expected (%lld -> %lld)",
+          iKey, ii, (bLeaf ? "%_rowid" : "%_parent"), iKey, iVal
+      );
+    }
+  }
+  rtreeCheckReset(pCheck, pStmt);
+}
+
+/*
+** Argument pCell points to an array of coordinates stored on an rtree page.
+** This function checks that the coordinates are internally consistent (no
+** x1>x2 conditions) and adds an error message to the RtreeCheck object
+** if they are not.
+**
+** Additionally, if pParent is not NULL, then it is assumed to point to
+** the array of coordinates on the parent page that bound the page
+** containing pCell. In this case it is also verified that the two
+** sets of coordinates are mutually consistent and an error message added
+** to the RtreeCheck object if they are not.
+*/
+static void rtreeCheckCellCoord(
+  RtreeCheck *pCheck,
+  i64 iNode,                      /* Node id to use in error messages */
+  int iCell,                      /* Cell number to use in error messages */
+  u8 *pCell,                      /* Pointer to cell coordinates */
+  u8 *pParent                     /* Pointer to parent coordinates */
+){
+  RtreeCoord c1, c2;
+  RtreeCoord p1, p2;
+  int i;
+
+  for(i=0; i<pCheck->nDim; i++){
+    readCoord(&pCell[4*2*i], &c1);
+    readCoord(&pCell[4*(2*i + 1)], &c2);
+
+    /* printf("%e, %e\n", c1.u.f, c2.u.f); */
+    if( pCheck->bInt ? c1.i>c2.i : c1.f>c2.f ){
+      rtreeCheckAppendMsg(pCheck,
+          "Dimension %d of cell %d on node %lld is corrupt", i, iCell, iNode
+      );
+    }
+
+    if( pParent ){
+      readCoord(&pParent[4*2*i], &p1);
+      readCoord(&pParent[4*(2*i + 1)], &p2);
+
+      if( (pCheck->bInt ? c1.i<p1.i : c1.f<p1.f)
+       || (pCheck->bInt ? c2.i>p2.i : c2.f>p2.f)
+      ){
+        rtreeCheckAppendMsg(pCheck,
+            "Dimension %d of cell %d on node %lld is corrupt relative to parent"
+            , i, iCell, iNode
+        );
+      }
+    }
+  }
+}
+
+/*
+** Run rtreecheck() checks on node iNode, which is at depth iDepth within
+** the r-tree structure. Argument aParent points to the array of coordinates
+** that bound node iNode on the parent node.
+**
+** If any problems are discovered, an error message is appended to the
+** report accumulated in the RtreeCheck object.
+*/
+static void rtreeCheckNode(
+  RtreeCheck *pCheck,
+  int iDepth,                     /* Depth of iNode (0==leaf) */
+  u8 *aParent,                    /* Buffer containing parent coords */
+  i64 iNode                       /* Node to check */
+){
+  u8 *aNode = 0;
+  int nNode = 0;
+
+  assert( iNode==1 || aParent!=0 );
+  assert( pCheck->nDim>0 );
+
+  aNode = rtreeCheckGetNode(pCheck, iNode, &nNode);
+  if( aNode ){
+    if( nNode<4 ){
+      rtreeCheckAppendMsg(pCheck,
+          "Node %lld is too small (%d bytes)", iNode, nNode
+      );
+    }else{
+      int nCell;                  /* Number of cells on page */
+      int i;                      /* Used to iterate through cells */
+      if( aParent==0 ){
+        iDepth = readInt16(aNode);
+        if( iDepth>RTREE_MAX_DEPTH ){
+          rtreeCheckAppendMsg(pCheck, "Rtree depth out of range (%d)", iDepth);
+          sqlite3_free(aNode);
+          return;
+        }
+      }
+      nCell = readInt16(&aNode[2]);
+      if( (4 + nCell*(8 + pCheck->nDim*2*4))>nNode ){
+        rtreeCheckAppendMsg(pCheck,
+            "Node %lld is too small for cell count of %d (%d bytes)",
+            iNode, nCell, nNode
+        );
+      }else{
+        for(i=0; i<nCell; i++){
+          u8 *pCell = &aNode[4 + i*(8 + pCheck->nDim*2*4)];
+          i64 iVal = readInt64(pCell);
+          rtreeCheckCellCoord(pCheck, iNode, i, &pCell[8], aParent);
+
+          if( iDepth>0 ){
+            rtreeCheckMapping(pCheck, 0, iVal, iNode);
+            rtreeCheckNode(pCheck, iDepth-1, &pCell[8], iVal);
+            pCheck->nNonLeaf++;
+          }else{
+            rtreeCheckMapping(pCheck, 1, iVal, iNode);
+            pCheck->nLeaf++;
+          }
+        }
+      }
+    }
+    sqlite3_free(aNode);
+  }
+}
+
+/*
+** The second argument to this function must be either "_rowid" or
+** "_parent". This function checks that the number of entries in the
+** %_rowid or %_parent table is exactly nExpect. If not, it adds
+** an error message to the report in the RtreeCheck object indicated
+** by the first argument.
+*/
+static void rtreeCheckCount(RtreeCheck *pCheck, const char *zTbl, i64 nExpect){
+  if( pCheck->rc==SQLITE_OK ){
+    sqlite3_stmt *pCount;
+    pCount = rtreeCheckPrepare(pCheck, "SELECT count(*) FROM %Q.'%q%s'",
+        pCheck->zDb, pCheck->zTab, zTbl
+    );
+    if( pCount ){
+      if( sqlite3_step(pCount)==SQLITE_ROW ){
+        i64 nActual = sqlite3_column_int64(pCount, 0);
+        if( nActual!=nExpect ){
+          rtreeCheckAppendMsg(pCheck, "Wrong number of entries in %%%s table"
+              " - expected %lld, actual %lld" , zTbl, nExpect, nActual
+          );
+        }
+      }
+      pCheck->rc = sqlite3_finalize(pCount);
+    }
+  }
+}
+
+/*
+** This function does the bulk of the work for the rtree integrity-check.
+** It is called by rtreecheck(), which is the SQL function implementation.
+*/
+static int rtreeCheckTable(
+  sqlite3 *db,                    /* Database handle to access db through */
+  const char *zDb,                /* Name of db ("main", "temp" etc.) */
+  const char *zTab,               /* Name of rtree table to check */
+  char **pzReport                 /* OUT: sqlite3_malloc'd report text */
+){
+  RtreeCheck check;               /* Common context for various routines */
+  sqlite3_stmt *pStmt = 0;        /* Used to find column count of rtree table */
+  int nAux = 0;                   /* Number of extra columns. */
+
+  /* Initialize the context object */
+  memset(&check, 0, sizeof(check));
+  check.db = db;
+  check.zDb = zDb;
+  check.zTab = zTab;
+
+  /* Find the number of auxiliary columns */
+  pStmt = rtreeCheckPrepare(&check, "SELECT * FROM %Q.'%q_rowid'", zDb, zTab);
+  if( pStmt ){
+    nAux = sqlite3_column_count(pStmt) - 2;
+    sqlite3_finalize(pStmt);
+  }else
+  if( check.rc!=SQLITE_NOMEM ){
+    check.rc = SQLITE_OK;
+  }
+
+  /* Find number of dimensions in the rtree table. */
+  pStmt = rtreeCheckPrepare(&check, "SELECT * FROM %Q.%Q", zDb, zTab);
+  if( pStmt ){
+    int rc;
+    check.nDim = (sqlite3_column_count(pStmt) - 1 - nAux) / 2;
+    if( check.nDim<1 ){
+      rtreeCheckAppendMsg(&check, "Schema corrupt or not an rtree");
+    }else if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      check.bInt = (sqlite3_column_type(pStmt, 1)==SQLITE_INTEGER);
+    }
+    rc = sqlite3_finalize(pStmt);
+    if( rc!=SQLITE_CORRUPT ) check.rc = rc;
+  }
+
+  /* Do the actual integrity-check */
+  if( check.nDim>=1 ){
+    if( check.rc==SQLITE_OK ){
+      rtreeCheckNode(&check, 0, 0, 1);
+    }
+    rtreeCheckCount(&check, "_rowid", check.nLeaf);
+    rtreeCheckCount(&check, "_parent", check.nNonLeaf);
+  }
+
+  /* Finalize SQL statements used by the integrity-check */
+  sqlite3_finalize(check.pGetNode);
+  sqlite3_finalize(check.aCheckMapping[0]);
+  sqlite3_finalize(check.aCheckMapping[1]);
+
+  *pzReport = check.zReport;
+  return check.rc;
+}
+
+/*
+** Implementation of the xIntegrity method for Rtree.
+*/
+static int rtreeIntegrity(
+  sqlite3_vtab *pVtab,   /* The virtual table to check */
+  const char *zSchema,   /* Schema in which the virtual table lives */
+  const char *zName,     /* Name of the virtual table */
+  int isQuick,           /* True for a quick_check */
+  char **pzErr           /* Write results here */
+){
+  Rtree *pRtree = (Rtree*)pVtab;
+  int rc;
+  assert( pzErr!=0 && *pzErr==0 );
+  UNUSED_PARAMETER(zSchema);
+  UNUSED_PARAMETER(zName);
+  UNUSED_PARAMETER(isQuick);
+  rc = rtreeCheckTable(pRtree->db, pRtree->zDb, pRtree->zName, pzErr);
+  if( rc==SQLITE_OK && *pzErr ){
+    *pzErr = sqlite3_mprintf("In RTree %s.%s:\n%z",
+                 pRtree->zDb, pRtree->zName, *pzErr);
+    if( (*pzErr)==0 ) rc = SQLITE_NOMEM;
+  }
+  return rc;
+}
+
+/*
+** Usage:
+**
+**   rtreecheck(<rtree-table>);
+**   rtreecheck(<database>, <rtree-table>);
+**
+** Invoking this SQL function runs an integrity-check on the named rtree
+** table. The integrity-check verifies the following:
+**
+**   1. For each cell in the r-tree structure (%_node table), that:
+**
+**       a) for each dimension, (coord1 <= coord2).
+**
+**       b) unless the cell is on the root node, that the cell is bounded
+**          by the parent cell on the parent node.
+**
+**       c) for leaf nodes, that there is an entry in the %_rowid
+**          table corresponding to the cell's rowid value that
+**          points to the correct node.
+**
+**       d) for cells on non-leaf nodes, that there is an entry in the
+**          %_parent table mapping from the cell's child node to the
+**          node that it resides on.
+**
+**   2. That there are the same number of entries in the %_rowid table
+**      as there are leaf cells in the r-tree structure, and that there
+**      is a leaf cell that corresponds to each entry in the %_rowid table.
+**
+**   3. That there are the same number of entries in the %_parent table
+**      as there are non-leaf cells in the r-tree structure, and that
+**      there is a non-leaf cell that corresponds to each entry in the
+**      %_parent table.
+*/
+static void rtreecheck(
+  sqlite3_context *ctx,
+  int nArg,
+  sqlite3_value **apArg
+){
+  if( nArg!=1 && nArg!=2 ){
+    sqlite3_result_error(ctx,
+        "wrong number of arguments to function rtreecheck()", -1
+    );
+  }else{
+    int rc;
+    char *zReport = 0;
+    const char *zDb = (const char*)sqlite3_value_text(apArg[0]);
+    const char *zTab;
+    if( nArg==1 ){
+      zTab = zDb;
+      zDb = "main";
+    }else{
+      zTab = (const char*)sqlite3_value_text(apArg[1]);
+    }
+    rc = rtreeCheckTable(sqlite3_context_db_handle(ctx), zDb, zTab, &zReport);
+    if( rc==SQLITE_OK ){
+      sqlite3_result_text(ctx, zReport ? zReport : "ok", -1, SQLITE_TRANSIENT);
+    }else{
+      sqlite3_result_error_code(ctx, rc);
+    }
+    sqlite3_free(zReport);
+  }
+}
+
+/* Conditionally include the geopoly code */
+#ifdef SQLITE_ENABLE_GEOPOLY
+/************** Include geopoly.c in the middle of rtree.c *******************/
+/************** Begin file geopoly.c *****************************************/
+/*
+** 2018-05-25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file implements an alternative R-Tree virtual table that
+** uses polygons to express the boundaries of 2-dimensional objects.
+**
+** This file is #include-ed onto the end of "rtree.c" so that it has
+** access to all of the R-Tree internals.
+*/
+/* #include <stdlib.h> */
+
+/* Enable -DGEOPOLY_ENABLE_DEBUG for debugging facilities */
+#ifdef GEOPOLY_ENABLE_DEBUG
+  static int geo_debug = 0;
+# define GEODEBUG(X) if(geo_debug)printf X
+#else
+# define GEODEBUG(X)
+#endif
+
+/* Character class routines */
+#ifdef sqlite3Isdigit
+   /* Use the SQLite core versions if this routine is part of the
+   ** SQLite amalgamation */
+#  define safe_isdigit(x)  sqlite3Isdigit(x)
+#  define safe_isalnum(x)  sqlite3Isalnum(x)
+#  define safe_isxdigit(x) sqlite3Isxdigit(x)
+#else
+   /* Use the standard library for separate compilation */
+#include <ctype.h>  /* amalgamator: keep */
+#  define safe_isdigit(x)  isdigit((unsigned char)(x))
+#  define safe_isalnum(x)  isalnum((unsigned char)(x))
+#  define safe_isxdigit(x) isxdigit((unsigned char)(x))
+#endif
+
+#ifndef JSON_NULL   /* The following stuff repeats things found in json1 */
+/*
+** Growing our own isspace() routine this way is twice as fast as
+** the library isspace() function.
+*/
+static const char geopolyIsSpace[] = {
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 1, 1, 0, 0, 1, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  1, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
+};
+#define fast_isspace(x) (geopolyIsSpace[(unsigned char)x])
+#endif /* JSON NULL - back to original code */
+
+/* Compiler and version */
+#ifndef GCC_VERSION
+#if defined(__GNUC__) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define GCC_VERSION (__GNUC__*1000000+__GNUC_MINOR__*1000+__GNUC_PATCHLEVEL__)
+#else
+# define GCC_VERSION 0
+#endif
+#endif
+#ifndef MSVC_VERSION
+#if defined(_MSC_VER) && !defined(SQLITE_DISABLE_INTRINSIC)
+# define MSVC_VERSION _MSC_VER
+#else
+# define MSVC_VERSION 0
+#endif
+#endif
+
+/* Datatype for coordinates
+*/
+typedef float GeoCoord;
+
+/*
+** Internal representation of a polygon.
+**
+** The polygon consists of a sequence of vertexes.  There is a line
+** segment between each pair of vertexes, and one final segment from
+** the last vertex back to the first.  (This differs from the GeoJSON
+** standard in which the final vertex is a repeat of the first.)
+**
+** The polygon follows the right-hand rule.  The area to the right of
+** each segment is "outside" and the area to the left is "inside".
+**
+** The on-disk representation consists of a 4-byte header followed by
+** the values.  The 4-byte header is:
+**
+**      encoding    (1 byte)   0=big-endian, 1=little-endian
+**      nvertex     (3 bytes)  Number of vertexes as a big-endian integer
+**
+** Enough space is allocated for 4 coordinates, to work around over-zealous
+** warnings coming from some compiler (notably, clang). In reality, the size
+** of each GeoPoly memory allocate is adjusted as necessary so that the
+** GeoPoly.a[] array at the end is the appropriate size.
+*/
+typedef struct GeoPoly GeoPoly;
+struct GeoPoly {
+  int nVertex;          /* Number of vertexes */
+  unsigned char hdr[4]; /* Header for on-disk representation */
+  GeoCoord a[8];        /* 2*nVertex values. X (longitude) first, then Y */
+};
+
+/* The size of a memory allocation needed for a GeoPoly object sufficient
+** to hold N coordinate pairs.
+*/
+#define GEOPOLY_SZ(N)  (sizeof(GeoPoly) + sizeof(GeoCoord)*2*((N)-4))
+
+/* Macros to access coordinates of a GeoPoly.
+** We have to use these macros, rather than just say p->a[i] in order
+** to silence (incorrect) UBSAN warnings if the array index is too large.
+*/
+#define GeoX(P,I)  (((GeoCoord*)(P)->a)[(I)*2])
+#define GeoY(P,I)  (((GeoCoord*)(P)->a)[(I)*2+1])
+
+
+/*
+** State of a parse of a GeoJSON input.
+*/
+typedef struct GeoParse GeoParse;
+struct GeoParse {
+  const unsigned char *z;   /* Unparsed input */
+  int nVertex;              /* Number of vertexes in a[] */
+  int nAlloc;               /* Space allocated to a[] */
+  int nErr;                 /* Number of errors encountered */
+  GeoCoord *a;          /* Array of vertexes.  From sqlite3_malloc64() */
+};
+
+/* Do a 4-byte byte swap */
+static void geopolySwab32(unsigned char *a){
+  unsigned char t = a[0];
+  a[0] = a[3];
+  a[3] = t;
+  t = a[1];
+  a[1] = a[2];
+  a[2] = t;
+}
+
+/* Skip whitespace.  Return the next non-whitespace character. */
+static char geopolySkipSpace(GeoParse *p){
+  while( fast_isspace(p->z[0]) ) p->z++;
+  return p->z[0];
+}
+
+/* Parse out a number.  Write the value into *pVal if pVal!=0.
+** return non-zero on success and zero if the next token is not a number.
+*/
+static int geopolyParseNumber(GeoParse *p, GeoCoord *pVal){
+  char c = geopolySkipSpace(p);
+  const unsigned char *z = p->z;
+  int j = 0;
+  int seenDP = 0;
+  int seenE = 0;
+  if( c=='-' ){
+    j = 1;
+    c = z[j];
+  }
+  if( c=='0' && z[j+1]>='0' && z[j+1]<='9' ) return 0;
+  for(;; j++){
+    c = z[j];
+    if( safe_isdigit(c) ) continue;
+    if( c=='.' ){
+      if( z[j-1]=='-' ) return 0;
+      if( seenDP ) return 0;
+      seenDP = 1;
+      continue;
+    }
+    if( c=='e' || c=='E' ){
+      if( z[j-1]<'0' ) return 0;
+      if( seenE ) return -1;
+      seenDP = seenE = 1;
+      c = z[j+1];
+      if( c=='+' || c=='-' ){
+        j++;
+        c = z[j+1];
+      }
+      if( c<'0' || c>'9' ) return 0;
+      continue;
+    }
+    break;
+  }
+  if( z[j-1]<'0' ) return 0;
+  if( pVal ){
+#ifdef SQLITE_AMALGAMATION
+     /* The sqlite3AtoF() routine is much much faster than atof(), if it
+     ** is available */
+     double r;
+     (void)sqlite3AtoF((const char*)p->z, &r, j, SQLITE_UTF8);
+     *pVal = r;
+#else
+     *pVal = (GeoCoord)atof((const char*)p->z);
+#endif
+  }
+  p->z += j;
+  return 1;
+}
+
+/*
+** If the input is a well-formed JSON array of coordinates with at least
+** four coordinates and where each coordinate is itself a two-value array,
+** then convert the JSON into a GeoPoly object and return a pointer to
+** that object.
+**
+** If any error occurs, return NULL.
+*/
+static GeoPoly *geopolyParseJson(const unsigned char *z, int *pRc){
+  GeoParse s;
+  int rc = SQLITE_OK;
+  memset(&s, 0, sizeof(s));
+  s.z = z;
+  if( geopolySkipSpace(&s)=='[' ){
+    s.z++;
+    while( geopolySkipSpace(&s)=='[' ){
+      int ii = 0;
+      char c;
+      s.z++;
+      if( s.nVertex>=s.nAlloc ){
+        GeoCoord *aNew;
+        s.nAlloc = s.nAlloc*2 + 16;
+        aNew = sqlite3_realloc64(s.a, s.nAlloc*sizeof(GeoCoord)*2 );
+        if( aNew==0 ){
+          rc = SQLITE_NOMEM;
+          s.nErr++;
+          break;
+        }
+        s.a = aNew;
+      }
+      while( geopolyParseNumber(&s, ii<=1 ? &s.a[s.nVertex*2+ii] : 0) ){
+        ii++;
+        if( ii==2 ) s.nVertex++;
+        c = geopolySkipSpace(&s);
+        s.z++;
+        if( c==',' ) continue;
+        if( c==']' && ii>=2 ) break;
+        s.nErr++;
+        rc = SQLITE_ERROR;
+        goto parse_json_err;
+      }
+      if( geopolySkipSpace(&s)==',' ){
+        s.z++;
+        continue;
+      }
+      break;
+    }
+    if( geopolySkipSpace(&s)==']'
+     && s.nVertex>=4
+     && s.a[0]==s.a[s.nVertex*2-2]
+     && s.a[1]==s.a[s.nVertex*2-1]
+     && (s.z++, geopolySkipSpace(&s)==0)
+    ){
+      GeoPoly *pOut;
+      int x = 1;
+      s.nVertex--;  /* Remove the redundant vertex at the end */
+      pOut = sqlite3_malloc64( GEOPOLY_SZ((sqlite3_int64)s.nVertex) );
+      x = 1;
+      if( pOut==0 ) goto parse_json_err;
+      pOut->nVertex = s.nVertex;
+      memcpy(pOut->a, s.a, s.nVertex*2*sizeof(GeoCoord));
+      pOut->hdr[0] = *(unsigned char*)&x;
+      pOut->hdr[1] = (s.nVertex>>16)&0xff;
+      pOut->hdr[2] = (s.nVertex>>8)&0xff;
+      pOut->hdr[3] = s.nVertex&0xff;
+      sqlite3_free(s.a);
+      if( pRc ) *pRc = SQLITE_OK;
+      return pOut;
+    }else{
+      s.nErr++;
+      rc = SQLITE_ERROR;
+    }
+  }
+parse_json_err:
+  if( pRc ) *pRc = rc;
+  sqlite3_free(s.a);
+  return 0;
+}
+
+/*
+** Given a function parameter, try to interpret it as a polygon, either
+** in the binary format or JSON text.  Compute a GeoPoly object and
+** return a pointer to that object.  Or if the input is not a well-formed
+** polygon, put an error message in sqlite3_context and return NULL.
+*/
+static GeoPoly *geopolyFuncParam(
+  sqlite3_context *pCtx,      /* Context for error messages */
+  sqlite3_value *pVal,        /* The value to decode */
+  int *pRc                    /* Write error here */
+){
+  GeoPoly *p = 0;
+  int nByte;
+  testcase( pCtx==0 );
+  if( sqlite3_value_type(pVal)==SQLITE_BLOB
+   && (nByte = sqlite3_value_bytes(pVal))>=(int)(4+6*sizeof(GeoCoord))
+  ){
+    const unsigned char *a = sqlite3_value_blob(pVal);
+    int nVertex;
+    if( a==0 ){
+      if( pCtx ) sqlite3_result_error_nomem(pCtx);
+      return 0;
+    }
+    nVertex = (a[1]<<16) + (a[2]<<8) + a[3];
+    if( (a[0]==0 || a[0]==1)
+     && (nVertex*2*sizeof(GeoCoord) + 4)==(unsigned int)nByte
+    ){
+      p = sqlite3_malloc64( sizeof(*p) + (nVertex-1)*2*sizeof(GeoCoord) );
+      if( p==0 ){
+        if( pRc ) *pRc = SQLITE_NOMEM;
+        if( pCtx ) sqlite3_result_error_nomem(pCtx);
+      }else{
+        int x = 1;
+        p->nVertex = nVertex;
+        memcpy(p->hdr, a, nByte);
+        if( a[0] != *(unsigned char*)&x ){
+          int ii;
+          for(ii=0; ii<nVertex; ii++){
+            geopolySwab32((unsigned char*)&GeoX(p,ii));
+            geopolySwab32((unsigned char*)&GeoY(p,ii));
+          }
+          p->hdr[0] ^= 1;
+        }
+      }
+    }
+    if( pRc ) *pRc = SQLITE_OK;
+    return p;
+  }else if( sqlite3_value_type(pVal)==SQLITE_TEXT ){
+    const unsigned char *zJson = sqlite3_value_text(pVal);
+    if( zJson==0 ){
+      if( pRc ) *pRc = SQLITE_NOMEM;
+      return 0;
+    }
+    return geopolyParseJson(zJson, pRc);
+  }else{
+    if( pRc ) *pRc = SQLITE_ERROR;
+    return 0;
+  }
+}
+
+/*
+** Implementation of the geopoly_blob(X) function.
+**
+** If the input is a well-formed Geopoly BLOB or JSON string
+** then return the BLOB representation of the polygon.  Otherwise
+** return NULL.
+*/
+static void geopolyBlobFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  (void)argc;
+  if( p ){
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** SQL function:     geopoly_json(X)
+**
+** Interpret X as a polygon and render it as a JSON array
+** of coordinates.  Or, if X is not a valid polygon, return NULL.
+*/
+static void geopolyJsonFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  (void)argc;
+  if( p ){
+    sqlite3 *db = sqlite3_context_db_handle(context);
+    sqlite3_str *x = sqlite3_str_new(db);
+    int i;
+    sqlite3_str_append(x, "[", 1);
+    for(i=0; i<p->nVertex; i++){
+      sqlite3_str_appendf(x, "[%!g,%!g],", GeoX(p,i), GeoY(p,i));
+    }
+    sqlite3_str_appendf(x, "[%!g,%!g]]", GeoX(p,0), GeoY(p,0));
+    sqlite3_result_text(context, sqlite3_str_finish(x), -1, sqlite3_free);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** SQL function:     geopoly_svg(X, ....)
+**
+** Interpret X as a polygon and render it as a SVG <polyline>.
+** Additional arguments are added as attributes to the <polyline>.
+*/
+static void geopolySvgFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p;
+  if( argc<1 ) return;
+  p = geopolyFuncParam(context, argv[0], 0);
+  if( p ){
+    sqlite3 *db = sqlite3_context_db_handle(context);
+    sqlite3_str *x = sqlite3_str_new(db);
+    int i;
+    char cSep = '\'';
+    sqlite3_str_appendf(x, "<polyline points=");
+    for(i=0; i<p->nVertex; i++){
+      sqlite3_str_appendf(x, "%c%g,%g", cSep, GeoX(p,i), GeoY(p,i));
+      cSep = ' ';
+    }
+    sqlite3_str_appendf(x, " %g,%g'", GeoX(p,0), GeoY(p,0));
+    for(i=1; i<argc; i++){
+      const char *z = (const char*)sqlite3_value_text(argv[i]);
+      if( z && z[0] ){
+        sqlite3_str_appendf(x, " %s", z);
+      }
+    }
+    sqlite3_str_appendf(x, "></polyline>");
+    sqlite3_result_text(context, sqlite3_str_finish(x), -1, sqlite3_free);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** SQL Function:      geopoly_xform(poly, A, B, C, D, E, F)
+**
+** Transform and/or translate a polygon as follows:
+**
+**      x1 = A*x0 + B*y0 + E
+**      y1 = C*x0 + D*y0 + F
+**
+** For a translation:
+**
+**      geopoly_xform(poly, 1, 0, 0, 1, x-offset, y-offset)
+**
+** Rotate by R around the point (0,0):
+**
+**      geopoly_xform(poly, cos(R), sin(R), -sin(R), cos(R), 0, 0)
+*/
+static void geopolyXformFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  double A = sqlite3_value_double(argv[1]);
+  double B = sqlite3_value_double(argv[2]);
+  double C = sqlite3_value_double(argv[3]);
+  double D = sqlite3_value_double(argv[4]);
+  double E = sqlite3_value_double(argv[5]);
+  double F = sqlite3_value_double(argv[6]);
+  GeoCoord x1, y1, x0, y0;
+  int ii;
+  (void)argc;
+  if( p ){
+    for(ii=0; ii<p->nVertex; ii++){
+      x0 = GeoX(p,ii);
+      y0 = GeoY(p,ii);
+      x1 = (GeoCoord)(A*x0 + B*y0 + E);
+      y1 = (GeoCoord)(C*x0 + D*y0 + F);
+      GeoX(p,ii) = x1;
+      GeoY(p,ii) = y1;
+    }
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Compute the area enclosed by the polygon.
+**
+** This routine can also be used to detect polygons that rotate in
+** the wrong direction.  Polygons are suppose to be counter-clockwise (CCW).
+** This routine returns a negative value for clockwise (CW) polygons.
+*/
+static double geopolyArea(GeoPoly *p){
+  double rArea = 0.0;
+  int ii;
+  for(ii=0; ii<p->nVertex-1; ii++){
+    rArea += (GeoX(p,ii) - GeoX(p,ii+1))           /* (x0 - x1) */
+              * (GeoY(p,ii) + GeoY(p,ii+1))        /* (y0 + y1) */
+              * 0.5;
+  }
+  rArea += (GeoX(p,ii) - GeoX(p,0))                /* (xN - x0) */
+           * (GeoY(p,ii) + GeoY(p,0))              /* (yN + y0) */
+           * 0.5;
+  return rArea;
+}
+
+/*
+** Implementation of the geopoly_area(X) function.
+**
+** If the input is a well-formed Geopoly BLOB then return the area
+** enclosed by the polygon.  If the polygon circulates clockwise instead
+** of counterclockwise (as it should) then return the negative of the
+** enclosed area.  Otherwise return NULL.
+*/
+static void geopolyAreaFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  (void)argc;
+  if( p ){
+    sqlite3_result_double(context, geopolyArea(p));
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Implementation of the geopoly_ccw(X) function.
+**
+** If the rotation of polygon X is clockwise (incorrect) instead of
+** counter-clockwise (the correct winding order according to RFC7946)
+** then reverse the order of the vertexes in polygon X.
+**
+** In other words, this routine returns a CCW polygon regardless of the
+** winding order of its input.
+**
+** Use this routine to sanitize historical inputs that that sometimes
+** contain polygons that wind in the wrong direction.
+*/
+static void geopolyCcwFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyFuncParam(context, argv[0], 0);
+  (void)argc;
+  if( p ){
+    if( geopolyArea(p)<0.0 ){
+      int ii, jj;
+      for(ii=1, jj=p->nVertex-1; ii<jj; ii++, jj--){
+        GeoCoord t = GeoX(p,ii);
+        GeoX(p,ii) = GeoX(p,jj);
+        GeoX(p,jj) = t;
+        t = GeoY(p,ii);
+        GeoY(p,ii) = GeoY(p,jj);
+        GeoY(p,jj) = t;
+      }
+    }
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+#define GEOPOLY_PI 3.1415926535897932385
+
+/* Fast approximation for sine(X) for X between -0.5*pi and 2*pi
+*/
+static double geopolySine(double r){
+  assert( r>=-0.5*GEOPOLY_PI && r<=2.0*GEOPOLY_PI );
+  if( r>=1.5*GEOPOLY_PI ){
+    r -= 2.0*GEOPOLY_PI;
+  }
+  if( r>=0.5*GEOPOLY_PI ){
+    return -geopolySine(r-GEOPOLY_PI);
+  }else{
+    double r2 = r*r;
+    double r3 = r2*r;
+    double r5 = r3*r2;
+    return 0.9996949*r - 0.1656700*r3 + 0.0075134*r5;
+  }
+}
+
+/*
+** Function:   geopoly_regular(X,Y,R,N)
+**
+** Construct a simple, convex, regular polygon centered at X, Y
+** with circumradius R and with N sides.
+*/
+static void geopolyRegularFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  double x = sqlite3_value_double(argv[0]);
+  double y = sqlite3_value_double(argv[1]);
+  double r = sqlite3_value_double(argv[2]);
+  int n = sqlite3_value_int(argv[3]);
+  int i;
+  GeoPoly *p;
+  (void)argc;
+
+  if( n<3 || r<=0.0 ) return;
+  if( n>1000 ) n = 1000;
+  p = sqlite3_malloc64( sizeof(*p) + (n-1)*2*sizeof(GeoCoord) );
+  if( p==0 ){
+    sqlite3_result_error_nomem(context);
+    return;
+  }
+  i = 1;
+  p->hdr[0] = *(unsigned char*)&i;
+  p->hdr[1] = 0;
+  p->hdr[2] = (n>>8)&0xff;
+  p->hdr[3] = n&0xff;
+  for(i=0; i<n; i++){
+    double rAngle = 2.0*GEOPOLY_PI*i/n;
+    GeoX(p,i) = x - r*geopolySine(rAngle-0.5*GEOPOLY_PI);
+    GeoY(p,i) = y + r*geopolySine(rAngle);
+  }
+  sqlite3_result_blob(context, p->hdr, 4+8*n, SQLITE_TRANSIENT);
+  sqlite3_free(p);
+}
+
+/*
+** If pPoly is a polygon, compute its bounding box. Then:
+**
+**    (1) if aCoord!=0 store the bounding box in aCoord, returning NULL
+**    (2) otherwise, compute a GeoPoly for the bounding box and return the
+**        new GeoPoly
+**
+** If pPoly is NULL but aCoord is not NULL, then compute a new GeoPoly from
+** the bounding box in aCoord and return a pointer to that GeoPoly.
+*/
+static GeoPoly *geopolyBBox(
+  sqlite3_context *context,   /* For recording the error */
+  sqlite3_value *pPoly,       /* The polygon */
+  RtreeCoord *aCoord,         /* Results here */
+  int *pRc                    /* Error code here */
+){
+  GeoPoly *pOut = 0;
+  GeoPoly *p;
+  float mnX, mxX, mnY, mxY;
+  if( pPoly==0 && aCoord!=0 ){
+    p = 0;
+    mnX = aCoord[0].f;
+    mxX = aCoord[1].f;
+    mnY = aCoord[2].f;
+    mxY = aCoord[3].f;
+    goto geopolyBboxFill;
+  }else{
+    p = geopolyFuncParam(context, pPoly, pRc);
+  }
+  if( p ){
+    int ii;
+    mnX = mxX = GeoX(p,0);
+    mnY = mxY = GeoY(p,0);
+    for(ii=1; ii<p->nVertex; ii++){
+      double r = GeoX(p,ii);
+      if( r<mnX ) mnX = (float)r;
+      else if( r>mxX ) mxX = (float)r;
+      r = GeoY(p,ii);
+      if( r<mnY ) mnY = (float)r;
+      else if( r>mxY ) mxY = (float)r;
+    }
+    if( pRc ) *pRc = SQLITE_OK;
+    if( aCoord==0 ){
+      geopolyBboxFill:
+      pOut = sqlite3_realloc64(p, GEOPOLY_SZ(4));
+      if( pOut==0 ){
+        sqlite3_free(p);
+        if( context ) sqlite3_result_error_nomem(context);
+        if( pRc ) *pRc = SQLITE_NOMEM;
+        return 0;
+      }
+      pOut->nVertex = 4;
+      ii = 1;
+      pOut->hdr[0] = *(unsigned char*)ⅈ
+      pOut->hdr[1] = 0;
+      pOut->hdr[2] = 0;
+      pOut->hdr[3] = 4;
+      GeoX(pOut,0) = mnX;
+      GeoY(pOut,0) = mnY;
+      GeoX(pOut,1) = mxX;
+      GeoY(pOut,1) = mnY;
+      GeoX(pOut,2) = mxX;
+      GeoY(pOut,2) = mxY;
+      GeoX(pOut,3) = mnX;
+      GeoY(pOut,3) = mxY;
+    }else{
+      sqlite3_free(p);
+      aCoord[0].f = mnX;
+      aCoord[1].f = mxX;
+      aCoord[2].f = mnY;
+      aCoord[3].f = mxY;
+    }
+  }else if( aCoord ){
+    memset(aCoord, 0, sizeof(RtreeCoord)*4);
+  }
+  return pOut;
+}
+
+/*
+** Implementation of the geopoly_bbox(X) SQL function.
+*/
+static void geopolyBBoxFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p = geopolyBBox(context, argv[0], 0, 0);
+  (void)argc;
+  if( p ){
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** State vector for the geopoly_group_bbox() aggregate function.
+*/
+typedef struct GeoBBox GeoBBox;
+struct GeoBBox {
+  int isInit;
+  RtreeCoord a[4];
+};
+
+
+/*
+** Implementation of the geopoly_group_bbox(X) aggregate SQL function.
+*/
+static void geopolyBBoxStep(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  RtreeCoord a[4];
+  int rc = SQLITE_OK;
+  (void)argc;
+  (void)geopolyBBox(context, argv[0], a, &rc);
+  if( rc==SQLITE_OK ){
+    GeoBBox *pBBox;
+    pBBox = (GeoBBox*)sqlite3_aggregate_context(context, sizeof(*pBBox));
+    if( pBBox==0 ) return;
+    if( pBBox->isInit==0 ){
+      pBBox->isInit = 1;
+      memcpy(pBBox->a, a, sizeof(RtreeCoord)*4);
+    }else{
+      if( a[0].f < pBBox->a[0].f ) pBBox->a[0] = a[0];
+      if( a[1].f > pBBox->a[1].f ) pBBox->a[1] = a[1];
+      if( a[2].f < pBBox->a[2].f ) pBBox->a[2] = a[2];
+      if( a[3].f > pBBox->a[3].f ) pBBox->a[3] = a[3];
+    }
+  }
+}
+static void geopolyBBoxFinal(
+  sqlite3_context *context
+){
+  GeoPoly *p;
+  GeoBBox *pBBox;
+  pBBox = (GeoBBox*)sqlite3_aggregate_context(context, 0);
+  if( pBBox==0 ) return;
+  p = geopolyBBox(context, 0, pBBox->a, 0);
+  if( p ){
+    sqlite3_result_blob(context, p->hdr,
+       4+8*p->nVertex, SQLITE_TRANSIENT);
+    sqlite3_free(p);
+  }
+}
+
+
+/*
+** Determine if point (x0,y0) is beneath line segment (x1,y1)->(x2,y2).
+** Returns:
+**
+**    +2  x0,y0 is on the line segement
+**
+**    +1  x0,y0 is beneath line segment
+**
+**    0   x0,y0 is not on or beneath the line segment or the line segment
+**        is vertical and x0,y0 is not on the line segment
+**
+** The left-most coordinate min(x1,x2) is not considered to be part of
+** the line segment for the purposes of this analysis.
+*/
+static int pointBeneathLine(
+  double x0, double y0,
+  double x1, double y1,
+  double x2, double y2
+){
+  double y;
+  if( x0==x1 && y0==y1 ) return 2;
+  if( x1<x2 ){
+    if( x0<=x1 || x0>x2 ) return 0;
+  }else if( x1>x2 ){
+    if( x0<=x2 || x0>x1 ) return 0;
+  }else{
+    /* Vertical line segment */
+    if( x0!=x1 ) return 0;
+    if( y0<y1 && y0<y2 ) return 0;
+    if( y0>y1 && y0>y2 ) return 0;
+    return 2;
+  }
+  y = y1 + (y2-y1)*(x0-x1)/(x2-x1);
+  if( y0==y ) return 2;
+  if( y0<y ) return 1;
+  return 0;
+}
+
+/*
+** SQL function:    geopoly_contains_point(P,X,Y)
+**
+** Return +2 if point X,Y is within polygon P.
+** Return +1 if point X,Y is on the polygon boundary.
+** Return 0 if point X,Y is outside the polygon
+*/
+static void geopolyContainsPointFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p1 = geopolyFuncParam(context, argv[0], 0);
+  double x0 = sqlite3_value_double(argv[1]);
+  double y0 = sqlite3_value_double(argv[2]);
+  int v = 0;
+  int cnt = 0;
+  int ii;
+  (void)argc;
+
+  if( p1==0 ) return;
+  for(ii=0; ii<p1->nVertex-1; ii++){
+    v = pointBeneathLine(x0,y0,GeoX(p1,ii), GeoY(p1,ii),
+                               GeoX(p1,ii+1),GeoY(p1,ii+1));
+    if( v==2 ) break;
+    cnt += v;
+  }
+  if( v!=2 ){
+    v = pointBeneathLine(x0,y0,GeoX(p1,ii), GeoY(p1,ii),
+                               GeoX(p1,0),  GeoY(p1,0));
+  }
+  if( v==2 ){
+    sqlite3_result_int(context, 1);
+  }else if( ((v+cnt)&1)==0 ){
+    sqlite3_result_int(context, 0);
+  }else{
+    sqlite3_result_int(context, 2);
+  }
+  sqlite3_free(p1);
+}
+
+/* Forward declaration */
+static int geopolyOverlap(GeoPoly *p1, GeoPoly *p2);
+
+/*
+** SQL function:    geopoly_within(P1,P2)
+**
+** Return +2 if P1 and P2 are the same polygon
+** Return +1 if P2 is contained within P1
+** Return 0 if any part of P2 is on the outside of P1
+**
+*/
+static void geopolyWithinFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p1 = geopolyFuncParam(context, argv[0], 0);
+  GeoPoly *p2 = geopolyFuncParam(context, argv[1], 0);
+  (void)argc;
+  if( p1 && p2 ){
+    int x = geopolyOverlap(p1, p2);
+    if( x<0 ){
+      sqlite3_result_error_nomem(context);
+    }else{
+      sqlite3_result_int(context, x==2 ? 1 : x==4 ? 2 : 0);
+    }
+  }
+  sqlite3_free(p1);
+  sqlite3_free(p2);
+}
+
+/* Objects used by the overlap algorihm. */
+typedef struct GeoEvent GeoEvent;
+typedef struct GeoSegment GeoSegment;
+typedef struct GeoOverlap GeoOverlap;
+struct GeoEvent {
+  double x;              /* X coordinate at which event occurs */
+  int eType;             /* 0 for ADD, 1 for REMOVE */
+  GeoSegment *pSeg;      /* The segment to be added or removed */
+  GeoEvent *pNext;       /* Next event in the sorted list */
+};
+struct GeoSegment {
+  double C, B;           /* y = C*x + B */
+  double y;              /* Current y value */
+  float y0;              /* Initial y value */
+  unsigned char side;    /* 1 for p1, 2 for p2 */
+  unsigned int idx;      /* Which segment within the side */
+  GeoSegment *pNext;     /* Next segment in a list sorted by y */
+};
+struct GeoOverlap {
+  GeoEvent *aEvent;          /* Array of all events */
+  GeoSegment *aSegment;      /* Array of all segments */
+  int nEvent;                /* Number of events */
+  int nSegment;              /* Number of segments */
+};
+
+/*
+** Add a single segment and its associated events.
+*/
+static void geopolyAddOneSegment(
+  GeoOverlap *p,
+  GeoCoord x0,
+  GeoCoord y0,
+  GeoCoord x1,
+  GeoCoord y1,
+  unsigned char side,
+  unsigned int idx
+){
+  GeoSegment *pSeg;
+  GeoEvent *pEvent;
+  if( x0==x1 ) return;  /* Ignore vertical segments */
+  if( x0>x1 ){
+    GeoCoord t = x0;
+    x0 = x1;
+    x1 = t;
+    t = y0;
+    y0 = y1;
+    y1 = t;
+  }
+  pSeg = p->aSegment + p->nSegment;
+  p->nSegment++;
+  pSeg->C = (y1-y0)/(x1-x0);
+  pSeg->B = y1 - x1*pSeg->C;
+  pSeg->y0 = y0;
+  pSeg->side = side;
+  pSeg->idx = idx;
+  pEvent = p->aEvent + p->nEvent;
+  p->nEvent++;
+  pEvent->x = x0;
+  pEvent->eType = 0;
+  pEvent->pSeg = pSeg;
+  pEvent = p->aEvent + p->nEvent;
+  p->nEvent++;
+  pEvent->x = x1;
+  pEvent->eType = 1;
+  pEvent->pSeg = pSeg;
+}
+
+
+
+/*
+** Insert all segments and events for polygon pPoly.
+*/
+static void geopolyAddSegments(
+  GeoOverlap *p,          /* Add segments to this Overlap object */
+  GeoPoly *pPoly,         /* Take all segments from this polygon */
+  unsigned char side      /* The side of pPoly */
+){
+  unsigned int i;
+  GeoCoord *x;
+  for(i=0; i<(unsigned)pPoly->nVertex-1; i++){
+    x = &GeoX(pPoly,i);
+    geopolyAddOneSegment(p, x[0], x[1], x[2], x[3], side, i);
+  }
+  x = &GeoX(pPoly,i);
+  geopolyAddOneSegment(p, x[0], x[1], pPoly->a[0], pPoly->a[1], side, i);
+}
+
+/*
+** Merge two lists of sorted events by X coordinate
+*/
+static GeoEvent *geopolyEventMerge(GeoEvent *pLeft, GeoEvent *pRight){
+  GeoEvent head, *pLast;
+  head.pNext = 0;
+  pLast = &head;
+  while( pRight && pLeft ){
+    if( pRight->x <= pLeft->x ){
+      pLast->pNext = pRight;
+      pLast = pRight;
+      pRight = pRight->pNext;
+    }else{
+      pLast->pNext = pLeft;
+      pLast = pLeft;
+      pLeft = pLeft->pNext;
+    }
+  }
+  pLast->pNext = pRight ? pRight : pLeft;
+  return head.pNext;
+}
+
+/*
+** Sort an array of nEvent event objects into a list.
+*/
+static GeoEvent *geopolySortEventsByX(GeoEvent *aEvent, int nEvent){
+  int mx = 0;
+  int i, j;
+  GeoEvent *p;
+  GeoEvent *a[50];
+  for(i=0; i<nEvent; i++){
+    p = &aEvent[i];
+    p->pNext = 0;
+    for(j=0; j<mx && a[j]; j++){
+      p = geopolyEventMerge(a[j], p);
+      a[j] = 0;
+    }
+    a[j] = p;
+    if( j>=mx ) mx = j+1;
+  }
+  p = 0;
+  for(i=0; i<mx; i++){
+    p = geopolyEventMerge(a[i], p);
+  }
+  return p;
+}
+
+/*
+** Merge two lists of sorted segments by Y, and then by C.
+*/
+static GeoSegment *geopolySegmentMerge(GeoSegment *pLeft, GeoSegment *pRight){
+  GeoSegment head, *pLast;
+  head.pNext = 0;
+  pLast = &head;
+  while( pRight && pLeft ){
+    double r = pRight->y - pLeft->y;
+    if( r==0.0 ) r = pRight->C - pLeft->C;
+    if( r<0.0 ){
+      pLast->pNext = pRight;
+      pLast = pRight;
+      pRight = pRight->pNext;
+    }else{
+      pLast->pNext = pLeft;
+      pLast = pLeft;
+      pLeft = pLeft->pNext;
+    }
+  }
+  pLast->pNext = pRight ? pRight : pLeft;
+  return head.pNext;
+}
+
+/*
+** Sort a list of GeoSegments in order of increasing Y and in the event of
+** a tie, increasing C (slope).
+*/
+static GeoSegment *geopolySortSegmentsByYAndC(GeoSegment *pList){
+  int mx = 0;
+  int i;
+  GeoSegment *p;
+  GeoSegment *a[50];
+  while( pList ){
+    p = pList;
+    pList = pList->pNext;
+    p->pNext = 0;
+    for(i=0; i<mx && a[i]; i++){
+      p = geopolySegmentMerge(a[i], p);
+      a[i] = 0;
+    }
+    a[i] = p;
+    if( i>=mx ) mx = i+1;
+  }
+  p = 0;
+  for(i=0; i<mx; i++){
+    p = geopolySegmentMerge(a[i], p);
+  }
+  return p;
+}
+
+/*
+** Determine the overlap between two polygons
+*/
+static int geopolyOverlap(GeoPoly *p1, GeoPoly *p2){
+  sqlite3_int64 nVertex = p1->nVertex + p2->nVertex + 2;
+  GeoOverlap *p;
+  sqlite3_int64 nByte;
+  GeoEvent *pThisEvent;
+  double rX;
+  int rc = 0;
+  int needSort = 0;
+  GeoSegment *pActive = 0;
+  GeoSegment *pSeg;
+  unsigned char aOverlap[4];
+
+  nByte = sizeof(GeoEvent)*nVertex*2
+           + sizeof(GeoSegment)*nVertex
+           + sizeof(GeoOverlap);
+  p = sqlite3_malloc64( nByte );
+  if( p==0 ) return -1;
+  p->aEvent = (GeoEvent*)&p[1];
+  p->aSegment = (GeoSegment*)&p->aEvent[nVertex*2];
+  p->nEvent = p->nSegment = 0;
+  geopolyAddSegments(p, p1, 1);
+  geopolyAddSegments(p, p2, 2);
+  pThisEvent = geopolySortEventsByX(p->aEvent, p->nEvent);
+  rX = pThisEvent && pThisEvent->x==0.0 ? -1.0 : 0.0;
+  memset(aOverlap, 0, sizeof(aOverlap));
+  while( pThisEvent ){
+    if( pThisEvent->x!=rX ){
+      GeoSegment *pPrev = 0;
+      int iMask = 0;
+      GEODEBUG(("Distinct X: %g\n", pThisEvent->x));
+      rX = pThisEvent->x;
+      if( needSort ){
+        GEODEBUG(("SORT\n"));
+        pActive = geopolySortSegmentsByYAndC(pActive);
+        needSort = 0;
+      }
+      for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
+        if( pPrev ){
+          if( pPrev->y!=pSeg->y ){
+            GEODEBUG(("MASK: %d\n", iMask));
+            aOverlap[iMask] = 1;
+          }
+        }
+        iMask ^= pSeg->side;
+        pPrev = pSeg;
+      }
+      pPrev = 0;
+      for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
+        double y = pSeg->C*rX + pSeg->B;
+        GEODEBUG(("Segment %d.%d %g->%g\n", pSeg->side, pSeg->idx, pSeg->y, y));
+        pSeg->y = y;
+        if( pPrev ){
+          if( pPrev->y>pSeg->y && pPrev->side!=pSeg->side ){
+            rc = 1;
+            GEODEBUG(("Crossing: %d.%d and %d.%d\n",
+                    pPrev->side, pPrev->idx,
+                    pSeg->side, pSeg->idx));
+            goto geopolyOverlapDone;
+          }else if( pPrev->y!=pSeg->y ){
+            GEODEBUG(("MASK: %d\n", iMask));
+            aOverlap[iMask] = 1;
+          }
+        }
+        iMask ^= pSeg->side;
+        pPrev = pSeg;
+      }
+    }
+    GEODEBUG(("%s %d.%d C=%g B=%g\n",
+      pThisEvent->eType ? "RM " : "ADD",
+      pThisEvent->pSeg->side, pThisEvent->pSeg->idx,
+      pThisEvent->pSeg->C,
+      pThisEvent->pSeg->B));
+    if( pThisEvent->eType==0 ){
+      /* Add a segment */
+      pSeg = pThisEvent->pSeg;
+      pSeg->y = pSeg->y0;
+      pSeg->pNext = pActive;
+      pActive = pSeg;
+      needSort = 1;
+    }else{
+      /* Remove a segment */
+      if( pActive==pThisEvent->pSeg ){
+        pActive = ALWAYS(pActive) ? pActive->pNext : 0;
+      }else{
+        for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
+          if( pSeg->pNext==pThisEvent->pSeg ){
+            pSeg->pNext = ALWAYS(pSeg->pNext) ? pSeg->pNext->pNext : 0;
+            break;
+          }
+        }
+      }
+    }
+    pThisEvent = pThisEvent->pNext;
+  }
+  if( aOverlap[3]==0 ){
+    rc = 0;
+  }else if( aOverlap[1]!=0 && aOverlap[2]==0 ){
+    rc = 3;
+  }else if( aOverlap[1]==0 && aOverlap[2]!=0 ){
+    rc = 2;
+  }else if( aOverlap[1]==0 && aOverlap[2]==0 ){
+    rc = 4;
+  }else{
+    rc = 1;
+  }
+
+geopolyOverlapDone:
+  sqlite3_free(p);
+  return rc;
+}
+
+/*
+** SQL function:    geopoly_overlap(P1,P2)
+**
+** Determine whether or not P1 and P2 overlap. Return value:
+**
+**   0     The two polygons are disjoint
+**   1     They overlap
+**   2     P1 is completely contained within P2
+**   3     P2 is completely contained within P1
+**   4     P1 and P2 are the same polygon
+**   NULL  Either P1 or P2 or both are not valid polygons
+*/
+static void geopolyOverlapFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  GeoPoly *p1 = geopolyFuncParam(context, argv[0], 0);
+  GeoPoly *p2 = geopolyFuncParam(context, argv[1], 0);
+  (void)argc;
+  if( p1 && p2 ){
+    int x = geopolyOverlap(p1, p2);
+    if( x<0 ){
+      sqlite3_result_error_nomem(context);
+    }else{
+      sqlite3_result_int(context, x);
+    }
+  }
+  sqlite3_free(p1);
+  sqlite3_free(p2);
+}
+
+/*
+** Enable or disable debugging output
+*/
+static void geopolyDebugFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  (void)context;
+  (void)argc;
+#ifdef GEOPOLY_ENABLE_DEBUG
+  geo_debug = sqlite3_value_int(argv[0]);
+#else
+  (void)argv;
+#endif
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the geopoly virtual table.
+**
+**   argv[0]   -> module name
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> column names...
+*/
+static int geopolyInit(
+  sqlite3 *db,                        /* Database connection */
+  void *pAux,                         /* One of the RTREE_COORD_* constants */
+  int argc, const char *const*argv,   /* Parameters to CREATE TABLE statement */
+  sqlite3_vtab **ppVtab,              /* OUT: New virtual table */
+  char **pzErr,                       /* OUT: Error message, if any */
+  int isCreate                        /* True for xCreate, false for xConnect */
+){
+  int rc = SQLITE_OK;
+  Rtree *pRtree;
+  sqlite3_int64 nDb;              /* Length of string argv[1] */
+  sqlite3_int64 nName;            /* Length of string argv[2] */
+  sqlite3_str *pSql;
+  char *zSql;
+  int ii;
+  (void)pAux;
+
+  sqlite3_vtab_config(db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1);
+  sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
+
+  /* Allocate the sqlite3_vtab structure */
+  nDb = strlen(argv[1]);
+  nName = strlen(argv[2]);
+  pRtree = (Rtree *)sqlite3_malloc64(sizeof(Rtree)+nDb+nName*2+8);
+  if( !pRtree ){
+    return SQLITE_NOMEM;
+  }
+  memset(pRtree, 0, sizeof(Rtree)+nDb+nName*2+8);
+  pRtree->nBusy = 1;
+  pRtree->base.pModule = &rtreeModule;
+  pRtree->zDb = (char *)&pRtree[1];
+  pRtree->zName = &pRtree->zDb[nDb+1];
+  pRtree->zNodeName = &pRtree->zName[nName+1];
+  pRtree->eCoordType = RTREE_COORD_REAL32;
+  pRtree->nDim = 2;
+  pRtree->nDim2 = 4;
+  memcpy(pRtree->zDb, argv[1], nDb);
+  memcpy(pRtree->zName, argv[2], nName);
+  memcpy(pRtree->zNodeName, argv[2], nName);
+  memcpy(&pRtree->zNodeName[nName], "_node", 6);
+
+
+  /* Create/Connect to the underlying relational database schema. If
+  ** that is successful, call sqlite3_declare_vtab() to configure
+  ** the r-tree table schema.
+  */
+  pSql = sqlite3_str_new(db);
+  sqlite3_str_appendf(pSql, "CREATE TABLE x(_shape");
+  pRtree->nAux = 1;         /* Add one for _shape */
+  pRtree->nAuxNotNull = 1;  /* The _shape column is always not-null */
+  for(ii=3; ii<argc; ii++){
+    pRtree->nAux++;
+    sqlite3_str_appendf(pSql, ",%s", argv[ii]);
+  }
+  sqlite3_str_appendf(pSql, ");");
+  zSql = sqlite3_str_finish(pSql);
+  if( !zSql ){
+    rc = SQLITE_NOMEM;
+  }else if( SQLITE_OK!=(rc = sqlite3_declare_vtab(db, zSql)) ){
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+  }
+  sqlite3_free(zSql);
+  if( rc ) goto geopolyInit_fail;
+  pRtree->nBytesPerCell = 8 + pRtree->nDim2*4;
+
+  /* Figure out the node size to use. */
+  rc = getNodeSize(db, pRtree, isCreate, pzErr);
+  if( rc ) goto geopolyInit_fail;
+  rc = rtreeSqlInit(pRtree, db, argv[1], argv[2], isCreate);
+  if( rc ){
+    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    goto geopolyInit_fail;
+  }
+
+  *ppVtab = (sqlite3_vtab *)pRtree;
+  return SQLITE_OK;
+
+geopolyInit_fail:
+  if( rc==SQLITE_OK ) rc = SQLITE_ERROR;
+  assert( *ppVtab==0 );
+  assert( pRtree->nBusy==1 );
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+
+/*
+** GEOPOLY virtual table module xCreate method.
+*/
+static int geopolyCreate(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  return geopolyInit(db, pAux, argc, argv, ppVtab, pzErr, 1);
+}
+
+/*
+** GEOPOLY virtual table module xConnect method.
+*/
+static int geopolyConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  return geopolyInit(db, pAux, argc, argv, ppVtab, pzErr, 0);
+}
+
+
+/*
+** GEOPOLY virtual table module xFilter method.
+**
+** Query plans:
+**
+**      1         rowid lookup
+**      2         search for objects overlapping the same bounding box
+**                that contains polygon argv[0]
+**      3         search for objects overlapping the same bounding box
+**                that contains polygon argv[0]
+**      4         full table scan
+*/
+static int geopolyFilter(
+  sqlite3_vtab_cursor *pVtabCursor,     /* The cursor to initialize */
+  int idxNum,                           /* Query plan */
+  const char *idxStr,                   /* Not Used */
+  int argc, sqlite3_value **argv        /* Parameters to the query plan */
+){
+  Rtree *pRtree = (Rtree *)pVtabCursor->pVtab;
+  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+  RtreeNode *pRoot = 0;
+  int rc = SQLITE_OK;
+  int iCell = 0;
+  (void)idxStr;
+
+  rtreeReference(pRtree);
+
+  /* Reset the cursor to the same state as rtreeOpen() leaves it in. */
+  resetCursor(pCsr);
+
+  pCsr->iStrategy = idxNum;
+  if( idxNum==1 ){
+    /* Special case - lookup by rowid. */
+    RtreeNode *pLeaf;        /* Leaf on which the required cell resides */
+    RtreeSearchPoint *p;     /* Search point for the leaf */
+    i64 iRowid = sqlite3_value_int64(argv[0]);
+    i64 iNode = 0;
+    rc = findLeafNode(pRtree, iRowid, &pLeaf, &iNode);
+    if( rc==SQLITE_OK && pLeaf!=0 ){
+      p = rtreeSearchPointNew(pCsr, RTREE_ZERO, 0);
+      assert( p!=0 );  /* Always returns pCsr->sPoint */
+      pCsr->aNode[0] = pLeaf;
+      p->id = iNode;
+      p->eWithin = PARTLY_WITHIN;
+      rc = nodeRowidIndex(pRtree, pLeaf, iRowid, &iCell);
+      p->iCell = (u8)iCell;
+      RTREE_QUEUE_TRACE(pCsr, "PUSH-F1:");
+    }else{
+      pCsr->atEOF = 1;
+    }
+  }else{
+    /* Normal case - r-tree scan. Set up the RtreeCursor.aConstraint array
+    ** with the configured constraints.
+    */
+    rc = nodeAcquire(pRtree, 1, 0, &pRoot);
+    if( rc==SQLITE_OK && idxNum<=3 ){
+      RtreeCoord bbox[4];
+      RtreeConstraint *p;
+      assert( argc==1 );
+      assert( argv[0]!=0 );
+      geopolyBBox(0, argv[0], bbox, &rc);
+      if( rc ){
+        goto geopoly_filter_end;
+      }
+      pCsr->aConstraint = p = sqlite3_malloc(sizeof(RtreeConstraint)*4);
+      pCsr->nConstraint = 4;
+      if( p==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(pCsr->aConstraint, 0, sizeof(RtreeConstraint)*4);
+        memset(pCsr->anQueue, 0, sizeof(u32)*(pRtree->iDepth + 1));
+        if( idxNum==2 ){
+          /* Overlap query */
+          p->op = 'B';
+          p->iCoord = 0;
+          p->u.rValue = bbox[1].f;
+          p++;
+          p->op = 'D';
+          p->iCoord = 1;
+          p->u.rValue = bbox[0].f;
+          p++;
+          p->op = 'B';
+          p->iCoord = 2;
+          p->u.rValue = bbox[3].f;
+          p++;
+          p->op = 'D';
+          p->iCoord = 3;
+          p->u.rValue = bbox[2].f;
+        }else{
+          /* Within query */
+          p->op = 'D';
+          p->iCoord = 0;
+          p->u.rValue = bbox[0].f;
+          p++;
+          p->op = 'B';
+          p->iCoord = 1;
+          p->u.rValue = bbox[1].f;
+          p++;
+          p->op = 'D';
+          p->iCoord = 2;
+          p->u.rValue = bbox[2].f;
+          p++;
+          p->op = 'B';
+          p->iCoord = 3;
+          p->u.rValue = bbox[3].f;
+        }
+      }
+    }
+    if( rc==SQLITE_OK ){
+      RtreeSearchPoint *pNew;
+      pNew = rtreeSearchPointNew(pCsr, RTREE_ZERO, (u8)(pRtree->iDepth+1));
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM;
+        goto geopoly_filter_end;
+      }
+      pNew->id = 1;
+      pNew->iCell = 0;
+      pNew->eWithin = PARTLY_WITHIN;
+      assert( pCsr->bPoint==1 );
+      pCsr->aNode[0] = pRoot;
+      pRoot = 0;
+      RTREE_QUEUE_TRACE(pCsr, "PUSH-Fm:");
+      rc = rtreeStepToLeaf(pCsr);
+    }
+  }
+
+geopoly_filter_end:
+  nodeRelease(pRtree, pRoot);
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+/*
+** Rtree virtual table module xBestIndex method. There are three
+** table scan strategies to choose from (in order from most to
+** least desirable):
+**
+**   idxNum     idxStr        Strategy
+**   ------------------------------------------------
+**     1        "rowid"       Direct lookup by rowid.
+**     2        "rtree"       R-tree overlap query using geopoly_overlap()
+**     3        "rtree"       R-tree within query using geopoly_within()
+**     4        "fullscan"    full-table scan.
+**   ------------------------------------------------
+*/
+static int geopolyBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  int ii;
+  int iRowidTerm = -1;
+  int iFuncTerm = -1;
+  int idxNum = 0;
+  (void)tab;
+
+  for(ii=0; ii<pIdxInfo->nConstraint; ii++){
+    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[ii];
+    if( !p->usable ) continue;
+    if( p->iColumn<0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ  ){
+      iRowidTerm = ii;
+      break;
+    }
+    if( p->iColumn==0 && p->op>=SQLITE_INDEX_CONSTRAINT_FUNCTION ){
+      /* p->op==SQLITE_INDEX_CONSTRAINT_FUNCTION for geopoly_overlap()
+      ** p->op==(SQLITE_INDEX_CONTRAINT_FUNCTION+1) for geopoly_within().
+      ** See geopolyFindFunction() */
+      iFuncTerm = ii;
+      idxNum = p->op - SQLITE_INDEX_CONSTRAINT_FUNCTION + 2;
+    }
+  }
+
+  if( iRowidTerm>=0 ){
+    pIdxInfo->idxNum = 1;
+    pIdxInfo->idxStr = "rowid";
+    pIdxInfo->aConstraintUsage[iRowidTerm].argvIndex = 1;
+    pIdxInfo->aConstraintUsage[iRowidTerm].omit = 1;
+    pIdxInfo->estimatedCost = 30.0;
+    pIdxInfo->estimatedRows = 1;
+    pIdxInfo->idxFlags = SQLITE_INDEX_SCAN_UNIQUE;
+    return SQLITE_OK;
+  }
+  if( iFuncTerm>=0 ){
+    pIdxInfo->idxNum = idxNum;
+    pIdxInfo->idxStr = "rtree";
+    pIdxInfo->aConstraintUsage[iFuncTerm].argvIndex = 1;
+    pIdxInfo->aConstraintUsage[iFuncTerm].omit = 0;
+    pIdxInfo->estimatedCost = 300.0;
+    pIdxInfo->estimatedRows = 10;
+    return SQLITE_OK;
+  }
+  pIdxInfo->idxNum = 4;
+  pIdxInfo->idxStr = "fullscan";
+  pIdxInfo->estimatedCost = 3000000.0;
+  pIdxInfo->estimatedRows = 100000;
+  return SQLITE_OK;
+}
+
+
+/*
+** GEOPOLY virtual table module xColumn method.
+*/
+static int geopolyColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
+  Rtree *pRtree = (Rtree *)cur->pVtab;
+  RtreeCursor *pCsr = (RtreeCursor *)cur;
+  RtreeSearchPoint *p = rtreeSearchPointFirst(pCsr);
+  int rc = SQLITE_OK;
+  RtreeNode *pNode = rtreeNodeOfFirstSearchPoint(pCsr, &rc);
+
+  if( rc ) return rc;
+  if( p==0 ) return SQLITE_OK;
+  if( i==0 && sqlite3_vtab_nochange(ctx) ) return SQLITE_OK;
+  if( i<=pRtree->nAux ){
+    if( !pCsr->bAuxValid ){
+      if( pCsr->pReadAux==0 ){
+        rc = sqlite3_prepare_v3(pRtree->db, pRtree->zReadAuxSql, -1, 0,
+                                &pCsr->pReadAux, 0);
+        if( rc ) return rc;
+      }
+      sqlite3_bind_int64(pCsr->pReadAux, 1,
+          nodeGetRowid(pRtree, pNode, p->iCell));
+      rc = sqlite3_step(pCsr->pReadAux);
+      if( rc==SQLITE_ROW ){
+        pCsr->bAuxValid = 1;
+      }else{
+        sqlite3_reset(pCsr->pReadAux);
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+        return rc;
+      }
+    }
+    sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pReadAux, i+2));
+  }
+  return SQLITE_OK;
+}
+
+
+/*
+** The xUpdate method for GEOPOLY module virtual tables.
+**
+** For DELETE:
+**
+**     argv[0] = the rowid to be deleted
+**
+** For INSERT:
+**
+**     argv[0] = SQL NULL
+**     argv[1] = rowid to insert, or an SQL NULL to select automatically
+**     argv[2] = _shape column
+**     argv[3] = first application-defined column....
+**
+** For UPDATE:
+**
+**     argv[0] = rowid to modify.  Never NULL
+**     argv[1] = rowid after the change.  Never NULL
+**     argv[2] = new value for _shape
+**     argv[3] = new value for first application-defined column....
+*/
+static int geopolyUpdate(
+  sqlite3_vtab *pVtab,
+  int nData,
+  sqlite3_value **aData,
+  sqlite_int64 *pRowid
+){
+  Rtree *pRtree = (Rtree *)pVtab;
+  int rc = SQLITE_OK;
+  RtreeCell cell;                 /* New cell to insert if nData>1 */
+  i64 oldRowid;                   /* The old rowid */
+  int oldRowidValid;              /* True if oldRowid is valid */
+  i64 newRowid;                   /* The new rowid */
+  int newRowidValid;              /* True if newRowid is valid */
+  int coordChange = 0;            /* Change in coordinates */
+
+  if( pRtree->nNodeRef ){
+    /* Unable to write to the btree while another cursor is reading from it,
+    ** since the write might do a rebalance which would disrupt the read
+    ** cursor. */
+    return SQLITE_LOCKED_VTAB;
+  }
+  rtreeReference(pRtree);
+  assert(nData>=1);
+
+  oldRowidValid = sqlite3_value_type(aData[0])!=SQLITE_NULL;;
+  oldRowid = oldRowidValid ? sqlite3_value_int64(aData[0]) : 0;
+  newRowidValid = nData>1 && sqlite3_value_type(aData[1])!=SQLITE_NULL;
+  newRowid = newRowidValid ? sqlite3_value_int64(aData[1]) : 0;
+  cell.iRowid = newRowid;
+
+  if( nData>1                                 /* not a DELETE */
+   && (!oldRowidValid                         /* INSERT */
+        || !sqlite3_value_nochange(aData[2])  /* UPDATE _shape */
+        || oldRowid!=newRowid)                /* Rowid change */
+  ){
+    assert( aData[2]!=0 );
+    geopolyBBox(0, aData[2], cell.aCoord, &rc);
+    if( rc ){
+      if( rc==SQLITE_ERROR ){
+        pVtab->zErrMsg =
+          sqlite3_mprintf("_shape does not contain a valid polygon");
+      }
+      goto geopoly_update_end;
+    }
+    coordChange = 1;
+
+    /* If a rowid value was supplied, check if it is already present in
+    ** the table. If so, the constraint has failed. */
+    if( newRowidValid && (!oldRowidValid || oldRowid!=newRowid) ){
+      int steprc;
+      sqlite3_bind_int64(pRtree->pReadRowid, 1, cell.iRowid);
+      steprc = sqlite3_step(pRtree->pReadRowid);
+      rc = sqlite3_reset(pRtree->pReadRowid);
+      if( SQLITE_ROW==steprc ){
+        if( sqlite3_vtab_on_conflict(pRtree->db)==SQLITE_REPLACE ){
+          rc = rtreeDeleteRowid(pRtree, cell.iRowid);
+        }else{
+          rc = rtreeConstraintError(pRtree, 0);
+        }
+      }
+    }
+  }
+
+  /* If aData[0] is not an SQL NULL value, it is the rowid of a
+  ** record to delete from the r-tree table. The following block does
+  ** just that.
+  */
+  if( rc==SQLITE_OK && (nData==1 || (coordChange && oldRowidValid)) ){
+    rc = rtreeDeleteRowid(pRtree, oldRowid);
+  }
+
+  /* If the aData[] array contains more than one element, elements
+  ** (aData[2]..aData[argc-1]) contain a new record to insert into
+  ** the r-tree structure.
+  */
+  if( rc==SQLITE_OK && nData>1 && coordChange ){
+    /* Insert the new record into the r-tree */
+    RtreeNode *pLeaf = 0;
+    if( !newRowidValid ){
+      rc = rtreeNewRowid(pRtree, &cell.iRowid);
+    }
+    *pRowid = cell.iRowid;
+    if( rc==SQLITE_OK ){
+      rc = ChooseLeaf(pRtree, &cell, 0, &pLeaf);
+    }
+    if( rc==SQLITE_OK ){
+      int rc2;
+      rc = rtreeInsertCell(pRtree, pLeaf, &cell, 0);
+      rc2 = nodeRelease(pRtree, pLeaf);
+      if( rc==SQLITE_OK ){
+        rc = rc2;
+      }
+    }
+  }
+
+  /* Change the data */
+  if( rc==SQLITE_OK && nData>1 ){
+    sqlite3_stmt *pUp = pRtree->pWriteAux;
+    int jj;
+    int nChange = 0;
+    sqlite3_bind_int64(pUp, 1, cell.iRowid);
+    assert( pRtree->nAux>=1 );
+    if( sqlite3_value_nochange(aData[2]) ){
+      sqlite3_bind_null(pUp, 2);
+    }else{
+      GeoPoly *p = 0;
+      if( sqlite3_value_type(aData[2])==SQLITE_TEXT
+       && (p = geopolyFuncParam(0, aData[2], &rc))!=0
+       && rc==SQLITE_OK
+      ){
+        sqlite3_bind_blob(pUp, 2, p->hdr, 4+8*p->nVertex, SQLITE_TRANSIENT);
+      }else{
+        sqlite3_bind_value(pUp, 2, aData[2]);
+      }
+      sqlite3_free(p);
+      nChange = 1;
+    }
+    for(jj=1; jj<nData-2; jj++){
+      nChange++;
+      sqlite3_bind_value(pUp, jj+2, aData[jj+2]);
+    }
+    if( nChange ){
+      sqlite3_step(pUp);
+      rc = sqlite3_reset(pUp);
+    }
+  }
+
+geopoly_update_end:
+  rtreeRelease(pRtree);
+  return rc;
+}
+
+/*
+** Report that geopoly_overlap() is an overloaded function suitable
+** for use in xBestIndex.
+*/
+static int geopolyFindFunction(
+  sqlite3_vtab *pVtab,
+  int nArg,
+  const char *zName,
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
+  void **ppArg
+){
+  (void)pVtab;
+  (void)nArg;
+  if( sqlite3_stricmp(zName, "geopoly_overlap")==0 ){
+    *pxFunc = geopolyOverlapFunc;
+    *ppArg = 0;
+    return SQLITE_INDEX_CONSTRAINT_FUNCTION;
+  }
+  if( sqlite3_stricmp(zName, "geopoly_within")==0 ){
+    *pxFunc = geopolyWithinFunc;
+    *ppArg = 0;
+    return SQLITE_INDEX_CONSTRAINT_FUNCTION+1;
+  }
+  return 0;
+}
+
+
+static sqlite3_module geopolyModule = {
+  3,                          /* iVersion */
+  geopolyCreate,              /* xCreate - create a table */
+  geopolyConnect,             /* xConnect - connect to an existing table */
+  geopolyBestIndex,           /* xBestIndex - Determine search strategy */
+  rtreeDisconnect,            /* xDisconnect - Disconnect from a table */
+  rtreeDestroy,               /* xDestroy - Drop a table */
+  rtreeOpen,                  /* xOpen - open a cursor */
+  rtreeClose,                 /* xClose - close a cursor */
+  geopolyFilter,              /* xFilter - configure scan constraints */
+  rtreeNext,                  /* xNext - advance a cursor */
+  rtreeEof,                   /* xEof */
+  geopolyColumn,              /* xColumn - read data */
+  rtreeRowid,                 /* xRowid - read data */
+  geopolyUpdate,              /* xUpdate - write data */
+  rtreeBeginTransaction,      /* xBegin - begin transaction */
+  rtreeEndTransaction,        /* xSync - sync transaction */
+  rtreeEndTransaction,        /* xCommit - commit transaction */
+  rtreeEndTransaction,        /* xRollback - rollback transaction */
+  geopolyFindFunction,        /* xFindFunction - function overloading */
+  rtreeRename,                /* xRename - rename the table */
+  rtreeSavepoint,             /* xSavepoint */
+  0,                          /* xRelease */
+  0,                          /* xRollbackTo */
+  rtreeShadowName,            /* xShadowName */
+  rtreeIntegrity              /* xIntegrity */
+};
+
+static int sqlite3_geopoly_init(sqlite3 *db){
+  int rc = SQLITE_OK;
+  static const struct {
+    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+    signed char nArg;
+    unsigned char bPure;
+    const char *zName;
+  } aFunc[] = {
+     { geopolyAreaFunc,          1, 1,    "geopoly_area"             },
+     { geopolyBlobFunc,          1, 1,    "geopoly_blob"             },
+     { geopolyJsonFunc,          1, 1,    "geopoly_json"             },
+     { geopolySvgFunc,          -1, 1,    "geopoly_svg"              },
+     { geopolyWithinFunc,        2, 1,    "geopoly_within"           },
+     { geopolyContainsPointFunc, 3, 1,    "geopoly_contains_point"   },
+     { geopolyOverlapFunc,       2, 1,    "geopoly_overlap"          },
+     { geopolyDebugFunc,         1, 0,    "geopoly_debug"            },
+     { geopolyBBoxFunc,          1, 1,    "geopoly_bbox"             },
+     { geopolyXformFunc,         7, 1,    "geopoly_xform"            },
+     { geopolyRegularFunc,       4, 1,    "geopoly_regular"          },
+     { geopolyCcwFunc,           1, 1,    "geopoly_ccw"              },
+  };
+  static const struct {
+    void (*xStep)(sqlite3_context*,int,sqlite3_value**);
+    void (*xFinal)(sqlite3_context*);
+    const char *zName;
+  } aAgg[] = {
+     { geopolyBBoxStep, geopolyBBoxFinal, "geopoly_group_bbox"    },
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(aFunc)/sizeof(aFunc[0]) && rc==SQLITE_OK; i++){
+    int enc;
+    if( aFunc[i].bPure ){
+      enc = SQLITE_UTF8|SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS;
+    }else{
+      enc = SQLITE_UTF8|SQLITE_DIRECTONLY;
+    }
+    rc = sqlite3_create_function(db, aFunc[i].zName, aFunc[i].nArg,
+                                 enc, 0,
+                                 aFunc[i].xFunc, 0, 0);
+  }
+  for(i=0; i<sizeof(aAgg)/sizeof(aAgg[0]) && rc==SQLITE_OK; i++){
+    rc = sqlite3_create_function(db, aAgg[i].zName, 1,
+              SQLITE_UTF8|SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS, 0,
+              0, aAgg[i].xStep, aAgg[i].xFinal);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_module_v2(db, "geopoly", &geopolyModule, 0, 0);
+  }
+  return rc;
+}
+
+/************** End of geopoly.c *********************************************/
+/************** Continuing where we left off in rtree.c **********************/
+#endif
+
+/*
+** Register the r-tree module with database handle db. This creates the
+** virtual table module "rtree" and the debugging/analysis scalar
+** function "rtreenode".
+*/
+SQLITE_PRIVATE int sqlite3RtreeInit(sqlite3 *db){
+  const int utf8 = SQLITE_UTF8;
+  int rc;
+
+  rc = sqlite3_create_function(db, "rtreenode", 2, utf8, 0, rtreenode, 0, 0);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(db, "rtreedepth", 1, utf8, 0,rtreedepth, 0, 0);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(db, "rtreecheck", -1, utf8, 0,rtreecheck, 0,0);
+  }
+  if( rc==SQLITE_OK ){
+#ifdef SQLITE_RTREE_INT_ONLY
+    void *c = (void *)RTREE_COORD_INT32;
+#else
+    void *c = (void *)RTREE_COORD_REAL32;
+#endif
+    rc = sqlite3_create_module_v2(db, "rtree", &rtreeModule, c, 0);
+  }
+  if( rc==SQLITE_OK ){
+    void *c = (void *)RTREE_COORD_INT32;
+    rc = sqlite3_create_module_v2(db, "rtree_i32", &rtreeModule, c, 0);
+  }
+#ifdef SQLITE_ENABLE_GEOPOLY
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_geopoly_init(db);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** This routine deletes the RtreeGeomCallback object that was attached
+** one of the SQL functions create by sqlite3_rtree_geometry_callback()
+** or sqlite3_rtree_query_callback().  In other words, this routine is the
+** destructor for an RtreeGeomCallback objecct.  This routine is called when
+** the corresponding SQL function is deleted.
+*/
+static void rtreeFreeCallback(void *p){
+  RtreeGeomCallback *pInfo = (RtreeGeomCallback*)p;
+  if( pInfo->xDestructor ) pInfo->xDestructor(pInfo->pContext);
+  sqlite3_free(p);
+}
+
+/*
+** This routine frees the BLOB that is returned by geomCallback().
+*/
+static void rtreeMatchArgFree(void *pArg){
+  int i;
+  RtreeMatchArg *p = (RtreeMatchArg*)pArg;
+  for(i=0; i<p->nParam; i++){
+    sqlite3_value_free(p->apSqlParam[i]);
+  }
+  sqlite3_free(p);
+}
+
+/*
+** Each call to sqlite3_rtree_geometry_callback() or
+** sqlite3_rtree_query_callback() creates an ordinary SQLite
+** scalar function that is implemented by this routine.
+**
+** All this function does is construct an RtreeMatchArg object that
+** contains the geometry-checking callback routines and a list of
+** parameters to this function, then return that RtreeMatchArg object
+** as a BLOB.
+**
+** The R-Tree MATCH operator will read the returned BLOB, deserialize
+** the RtreeMatchArg object, and use the RtreeMatchArg object to figure
+** out which elements of the R-Tree should be returned by the query.
+*/
+static void geomCallback(sqlite3_context *ctx, int nArg, sqlite3_value **aArg){
+  RtreeGeomCallback *pGeomCtx = (RtreeGeomCallback *)sqlite3_user_data(ctx);
+  RtreeMatchArg *pBlob;
+  sqlite3_int64 nBlob;
+  int memErr = 0;
+
+  nBlob = sizeof(RtreeMatchArg) + (nArg-1)*sizeof(RtreeDValue)
+           + nArg*sizeof(sqlite3_value*);
+  pBlob = (RtreeMatchArg *)sqlite3_malloc64(nBlob);
+  if( !pBlob ){
+    sqlite3_result_error_nomem(ctx);
+  }else{
+    int i;
+    pBlob->iSize = nBlob;
+    pBlob->cb = pGeomCtx[0];
+    pBlob->apSqlParam = (sqlite3_value**)&pBlob->aParam[nArg];
+    pBlob->nParam = nArg;
+    for(i=0; i<nArg; i++){
+      pBlob->apSqlParam[i] = sqlite3_value_dup(aArg[i]);
+      if( pBlob->apSqlParam[i]==0 ) memErr = 1;
+#ifdef SQLITE_RTREE_INT_ONLY
+      pBlob->aParam[i] = sqlite3_value_int64(aArg[i]);
+#else
+      pBlob->aParam[i] = sqlite3_value_double(aArg[i]);
+#endif
+    }
+    if( memErr ){
+      sqlite3_result_error_nomem(ctx);
+      rtreeMatchArgFree(pBlob);
+    }else{
+      sqlite3_result_pointer(ctx, pBlob, "RtreeMatchArg", rtreeMatchArgFree);
+    }
+  }
+}
+
+/*
+** Register a new geometry function for use with the r-tree MATCH operator.
+*/
+SQLITE_API int sqlite3_rtree_geometry_callback(
+  sqlite3 *db,                  /* Register SQL function on this connection */
+  const char *zGeom,            /* Name of the new SQL function */
+  int (*xGeom)(sqlite3_rtree_geometry*,int,RtreeDValue*,int*), /* Callback */
+  void *pContext                /* Extra data associated with the callback */
+){
+  RtreeGeomCallback *pGeomCtx;      /* Context object for new user-function */
+
+  /* Allocate and populate the context object. */
+  pGeomCtx = (RtreeGeomCallback *)sqlite3_malloc(sizeof(RtreeGeomCallback));
+  if( !pGeomCtx ) return SQLITE_NOMEM;
+  pGeomCtx->xGeom = xGeom;
+  pGeomCtx->xQueryFunc = 0;
+  pGeomCtx->xDestructor = 0;
+  pGeomCtx->pContext = pContext;
+  return sqlite3_create_function_v2(db, zGeom, -1, SQLITE_ANY,
+      (void *)pGeomCtx, geomCallback, 0, 0, rtreeFreeCallback
+  );
+}
+
+/*
+** Register a new 2nd-generation geometry function for use with the
+** r-tree MATCH operator.
+*/
+SQLITE_API int sqlite3_rtree_query_callback(
+  sqlite3 *db,                 /* Register SQL function on this connection */
+  const char *zQueryFunc,      /* Name of new SQL function */
+  int (*xQueryFunc)(sqlite3_rtree_query_info*), /* Callback */
+  void *pContext,              /* Extra data passed into the callback */
+  void (*xDestructor)(void*)   /* Destructor for the extra data */
+){
+  RtreeGeomCallback *pGeomCtx;      /* Context object for new user-function */
+
+  /* Allocate and populate the context object. */
+  pGeomCtx = (RtreeGeomCallback *)sqlite3_malloc(sizeof(RtreeGeomCallback));
+  if( !pGeomCtx ){
+    if( xDestructor ) xDestructor(pContext);
+    return SQLITE_NOMEM;
+  }
+  pGeomCtx->xGeom = 0;
+  pGeomCtx->xQueryFunc = xQueryFunc;
+  pGeomCtx->xDestructor = xDestructor;
+  pGeomCtx->pContext = pContext;
+  return sqlite3_create_function_v2(db, zQueryFunc, -1, SQLITE_ANY,
+      (void *)pGeomCtx, geomCallback, 0, 0, rtreeFreeCallback
+  );
+}
+
+#ifndef SQLITE_CORE
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_rtree_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi)
+  return sqlite3RtreeInit(db);
+}
+#endif
+
+#endif
+
+/************** End of rtree.c ***********************************************/
+/************** Begin file icu.c *********************************************/
+/*
+** 2007 May 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** $Id: icu.c,v 1.7 2007/12/13 21:54:11 drh Exp $
+**
+** This file implements an integration between the ICU library
+** ("International Components for Unicode", an open-source library
+** for handling unicode data) and SQLite. The integration uses
+** ICU to provide the following to SQLite:
+**
+**   * An implementation of the SQL regexp() function (and hence REGEXP
+**     operator) using the ICU uregex_XX() APIs.
+**
+**   * Implementations of the SQL scalar upper() and lower() functions
+**     for case mapping.
+**
+**   * Integration of ICU and SQLite collation sequences.
+**
+**   * An implementation of the LIKE operator that uses ICU to
+**     provide case-independent matching.
+*/
+
+#if !defined(SQLITE_CORE)                  \
+ || defined(SQLITE_ENABLE_ICU)             \
+ || defined(SQLITE_ENABLE_ICU_COLLATIONS)
+
+/* Include ICU headers */
+#include <unicode/utypes.h>
+#include <unicode/uregex.h>
+#include <unicode/ustring.h>
+#include <unicode/ucol.h>
+
+/* #include <assert.h> */
+
+#ifndef SQLITE_CORE
+/*   #include "sqlite3ext.h" */
+  SQLITE_EXTENSION_INIT1
+#else
+/*   #include "sqlite3.h" */
+#endif
+
+/*
+** This function is called when an ICU function called from within
+** the implementation of an SQL scalar function returns an error.
+**
+** The scalar function context passed as the first argument is
+** loaded with an error message based on the following two args.
+*/
+static void icuFunctionError(
+  sqlite3_context *pCtx,       /* SQLite scalar function context */
+  const char *zName,           /* Name of ICU function that failed */
+  UErrorCode e                 /* Error code returned by ICU function */
+){
+  char zBuf[128];
+  sqlite3_snprintf(128, zBuf, "ICU error: %s(): %s", zName, u_errorName(e));
+  zBuf[127] = '\0';
+  sqlite3_result_error(pCtx, zBuf, -1);
+}
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_ICU)
+
+/*
+** Maximum length (in bytes) of the pattern in a LIKE or GLOB
+** operator.
+*/
+#ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
+# define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
+#endif
+
+/*
+** Version of sqlite3_free() that is always a function, never a macro.
+*/
+static void xFree(void *p){
+  sqlite3_free(p);
+}
+
+/*
+** This lookup table is used to help decode the first byte of
+** a multi-byte UTF8 character. It is copied here from SQLite source
+** code file utf8.c.
+*/
+static const unsigned char icuUtf8Trans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+#define SQLITE_ICU_READ_UTF8(zIn, c)                       \
+  c = *(zIn++);                                            \
+  if( c>=0xc0 ){                                           \
+    c = icuUtf8Trans1[c-0xc0];                             \
+    while( (*zIn & 0xc0)==0x80 ){                          \
+      c = (c<<6) + (0x3f & *(zIn++));                      \
+    }                                                      \
+  }
+
+#define SQLITE_ICU_SKIP_UTF8(zIn)                          \
+  assert( *zIn );                                          \
+  if( *(zIn++)>=0xc0 ){                                    \
+    while( (*zIn & 0xc0)==0x80 ){zIn++;}                   \
+  }
+
+
+/*
+** Compare two UTF-8 strings for equality where the first string is
+** a "LIKE" expression. Return true (1) if they are the same and
+** false (0) if they are different.
+*/
+static int icuLikeCompare(
+  const uint8_t *zPattern,   /* LIKE pattern */
+  const uint8_t *zString,    /* The UTF-8 string to compare against */
+  const UChar32 uEsc         /* The escape character */
+){
+  static const uint32_t MATCH_ONE = (uint32_t)'_';
+  static const uint32_t MATCH_ALL = (uint32_t)'%';
+
+  int prevEscape = 0;     /* True if the previous character was uEsc */
+
+  while( 1 ){
+
+    /* Read (and consume) the next character from the input pattern. */
+    uint32_t uPattern;
+    SQLITE_ICU_READ_UTF8(zPattern, uPattern);
+    if( uPattern==0 ) break;
+
+    /* There are now 4 possibilities:
+    **
+    **     1. uPattern is an unescaped match-all character "%",
+    **     2. uPattern is an unescaped match-one character "_",
+    **     3. uPattern is an unescaped escape character, or
+    **     4. uPattern is to be handled as an ordinary character
+    */
+    if( uPattern==MATCH_ALL && !prevEscape && uPattern!=(uint32_t)uEsc ){
+      /* Case 1. */
+      uint8_t c;
+
+      /* Skip any MATCH_ALL or MATCH_ONE characters that follow a
+      ** MATCH_ALL. For each MATCH_ONE, skip one character in the
+      ** test string.
+      */
+      while( (c=*zPattern) == MATCH_ALL || c == MATCH_ONE ){
+        if( c==MATCH_ONE ){
+          if( *zString==0 ) return 0;
+          SQLITE_ICU_SKIP_UTF8(zString);
+        }
+        zPattern++;
+      }
+
+      if( *zPattern==0 ) return 1;
+
+      while( *zString ){
+        if( icuLikeCompare(zPattern, zString, uEsc) ){
+          return 1;
+        }
+        SQLITE_ICU_SKIP_UTF8(zString);
+      }
+      return 0;
+
+    }else if( uPattern==MATCH_ONE && !prevEscape && uPattern!=(uint32_t)uEsc ){
+      /* Case 2. */
+      if( *zString==0 ) return 0;
+      SQLITE_ICU_SKIP_UTF8(zString);
+
+    }else if( uPattern==(uint32_t)uEsc && !prevEscape ){
+      /* Case 3. */
+      prevEscape = 1;
+
+    }else{
+      /* Case 4. */
+      uint32_t uString;
+      SQLITE_ICU_READ_UTF8(zString, uString);
+      uString = (uint32_t)u_foldCase((UChar32)uString, U_FOLD_CASE_DEFAULT);
+      uPattern = (uint32_t)u_foldCase((UChar32)uPattern, U_FOLD_CASE_DEFAULT);
+      if( uString!=uPattern ){
+        return 0;
+      }
+      prevEscape = 0;
+    }
+  }
+
+  return *zString==0;
+}
+
+/*
+** Implementation of the like() SQL function.  This function implements
+** the build-in LIKE operator.  The first argument to the function is the
+** pattern and the second argument is the string.  So, the SQL statements:
+**
+**       A LIKE B
+**
+** is implemented as like(B, A). If there is an escape character E,
+**
+**       A LIKE B ESCAPE E
+**
+** is mapped to like(B, A, E).
+*/
+static void icuLikeFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const unsigned char *zA = sqlite3_value_text(argv[0]);
+  const unsigned char *zB = sqlite3_value_text(argv[1]);
+  UChar32 uEsc = 0;
+
+  /* Limit the length of the LIKE or GLOB pattern to avoid problems
+  ** of deep recursion and N*N behavior in patternCompare().
+  */
+  if( sqlite3_value_bytes(argv[0])>SQLITE_MAX_LIKE_PATTERN_LENGTH ){
+    sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
+    return;
+  }
+
+
+  if( argc==3 ){
+    /* The escape character string must consist of a single UTF-8 character.
+    ** Otherwise, return an error.
+    */
+    int nE= sqlite3_value_bytes(argv[2]);
+    const unsigned char *zE = sqlite3_value_text(argv[2]);
+    int i = 0;
+    if( zE==0 ) return;
+    U8_NEXT(zE, i, nE, uEsc);
+    if( i!=nE){
+      sqlite3_result_error(context,
+          "ESCAPE expression must be a single character", -1);
+      return;
+    }
+  }
+
+  if( zA && zB ){
+    sqlite3_result_int(context, icuLikeCompare(zA, zB, uEsc));
+  }
+}
+
+/*
+** Function to delete compiled regexp objects. Registered as
+** a destructor function with sqlite3_set_auxdata().
+*/
+static void icuRegexpDelete(void *p){
+  URegularExpression *pExpr = (URegularExpression *)p;
+  uregex_close(pExpr);
+}
+
+/*
+** Implementation of SQLite REGEXP operator. This scalar function takes
+** two arguments. The first is a regular expression pattern to compile
+** the second is a string to match against that pattern. If either
+** argument is an SQL NULL, then NULL Is returned. Otherwise, the result
+** is 1 if the string matches the pattern, or 0 otherwise.
+**
+** SQLite maps the regexp() function to the regexp() operator such
+** that the following two are equivalent:
+**
+**     zString REGEXP zPattern
+**     regexp(zPattern, zString)
+**
+** Uses the following ICU regexp APIs:
+**
+**     uregex_open()
+**     uregex_matches()
+**     uregex_close()
+*/
+static void icuRegexpFunc(sqlite3_context *p, int nArg, sqlite3_value **apArg){
+  UErrorCode status = U_ZERO_ERROR;
+  URegularExpression *pExpr;
+  UBool res;
+  const UChar *zString = sqlite3_value_text16(apArg[1]);
+
+  (void)nArg;  /* Unused parameter */
+
+  /* If the left hand side of the regexp operator is NULL,
+  ** then the result is also NULL.
+  */
+  if( !zString ){
+    return;
+  }
+
+  pExpr = sqlite3_get_auxdata(p, 0);
+  if( !pExpr ){
+    const UChar *zPattern = sqlite3_value_text16(apArg[0]);
+    if( !zPattern ){
+      return;
+    }
+    pExpr = uregex_open(zPattern, -1, 0, 0, &status);
+
+    if( U_SUCCESS(status) ){
+      sqlite3_set_auxdata(p, 0, pExpr, icuRegexpDelete);
+      pExpr = sqlite3_get_auxdata(p, 0);
+    }
+    if( !pExpr ){
+      icuFunctionError(p, "uregex_open", status);
+      return;
+    }
+  }
+
+  /* Configure the text that the regular expression operates on. */
+  uregex_setText(pExpr, zString, -1, &status);
+  if( !U_SUCCESS(status) ){
+    icuFunctionError(p, "uregex_setText", status);
+    return;
+  }
+
+  /* Attempt the match */
+  res = uregex_matches(pExpr, 0, &status);
+  if( !U_SUCCESS(status) ){
+    icuFunctionError(p, "uregex_matches", status);
+    return;
+  }
+
+  /* Set the text that the regular expression operates on to a NULL
+  ** pointer. This is not really necessary, but it is tidier than
+  ** leaving the regular expression object configured with an invalid
+  ** pointer after this function returns.
+  */
+  uregex_setText(pExpr, 0, 0, &status);
+
+  /* Return 1 or 0. */
+  sqlite3_result_int(p, res ? 1 : 0);
+}
+
+/*
+** Implementations of scalar functions for case mapping - upper() and
+** lower(). Function upper() converts its input to upper-case (ABC).
+** Function lower() converts to lower-case (abc).
+**
+** ICU provides two types of case mapping, "general" case mapping and
+** "language specific". Refer to ICU documentation for the differences
+** between the two.
+**
+** To utilise "general" case mapping, the upper() or lower() scalar
+** functions are invoked with one argument:
+**
+**     upper('ABC') -> 'abc'
+**     lower('abc') -> 'ABC'
+**
+** To access ICU "language specific" case mapping, upper() or lower()
+** should be invoked with two arguments. The second argument is the name
+** of the locale to use. Passing an empty string ("") or SQL NULL value
+** as the second argument is the same as invoking the 1 argument version
+** of upper() or lower().
+**
+**     lower('I', 'en_us') -> 'i'
+**     lower('I', 'tr_tr') -> '\u131' (small dotless i)
+**
+** http://www.icu-project.org/userguide/posix.html#case_mappings
+*/
+static void icuCaseFunc16(sqlite3_context *p, int nArg, sqlite3_value **apArg){
+  const UChar *zInput;            /* Pointer to input string */
+  UChar *zOutput = 0;             /* Pointer to output buffer */
+  int nInput;                     /* Size of utf-16 input string in bytes */
+  int nOut;                       /* Size of output buffer in bytes */
+  int cnt;
+  int bToUpper;                   /* True for toupper(), false for tolower() */
+  UErrorCode status;
+  const char *zLocale = 0;
+
+  assert(nArg==1 || nArg==2);
+  bToUpper = (sqlite3_user_data(p)!=0);
+  if( nArg==2 ){
+    zLocale = (const char *)sqlite3_value_text(apArg[1]);
+  }
+
+  zInput = sqlite3_value_text16(apArg[0]);
+  if( !zInput ){
+    return;
+  }
+  nOut = nInput = sqlite3_value_bytes16(apArg[0]);
+  if( nOut==0 ){
+    sqlite3_result_text16(p, "", 0, SQLITE_STATIC);
+    return;
+  }
+
+  for(cnt=0; cnt<2; cnt++){
+    UChar *zNew = sqlite3_realloc(zOutput, nOut);
+    if( zNew==0 ){
+      sqlite3_free(zOutput);
+      sqlite3_result_error_nomem(p);
+      return;
+    }
+    zOutput = zNew;
+    status = U_ZERO_ERROR;
+    if( bToUpper ){
+      nOut = 2*u_strToUpper(zOutput,nOut/2,zInput,nInput/2,zLocale,&status);
+    }else{
+      nOut = 2*u_strToLower(zOutput,nOut/2,zInput,nInput/2,zLocale,&status);
+    }
+
+    if( U_SUCCESS(status) ){
+      sqlite3_result_text16(p, zOutput, nOut, xFree);
+    }else if( status==U_BUFFER_OVERFLOW_ERROR ){
+      assert( cnt==0 );
+      continue;
+    }else{
+      icuFunctionError(p, bToUpper ? "u_strToUpper" : "u_strToLower", status);
+    }
+    return;
+  }
+  assert( 0 );     /* Unreachable */
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_ICU) */
+
+/*
+** Collation sequence destructor function. The pCtx argument points to
+** a UCollator structure previously allocated using ucol_open().
+*/
+static void icuCollationDel(void *pCtx){
+  UCollator *p = (UCollator *)pCtx;
+  ucol_close(p);
+}
+
+/*
+** Collation sequence comparison function. The pCtx argument points to
+** a UCollator structure previously allocated using ucol_open().
+*/
+static int icuCollationColl(
+  void *pCtx,
+  int nLeft,
+  const void *zLeft,
+  int nRight,
+  const void *zRight
+){
+  UCollationResult res;
+  UCollator *p = (UCollator *)pCtx;
+  res = ucol_strcoll(p, (UChar *)zLeft, nLeft/2, (UChar *)zRight, nRight/2);
+  switch( res ){
+    case UCOL_LESS:    return -1;
+    case UCOL_GREATER: return +1;
+    case UCOL_EQUAL:   return 0;
+  }
+  assert(!"Unexpected return value from ucol_strcoll()");
+  return 0;
+}
+
+/*
+** Implementation of the scalar function icu_load_collation().
+**
+** This scalar function is used to add ICU collation based collation
+** types to an SQLite database connection. It is intended to be called
+** as follows:
+**
+**     SELECT icu_load_collation(<locale>, <collation-name>);
+**
+** Where <locale> is a string containing an ICU locale identifier (i.e.
+** "en_AU", "tr_TR" etc.) and <collation-name> is the name of the
+** collation sequence to create.
+*/
+static void icuLoadCollation(
+  sqlite3_context *p,
+  int nArg,
+  sqlite3_value **apArg
+){
+  sqlite3 *db = (sqlite3 *)sqlite3_user_data(p);
+  UErrorCode status = U_ZERO_ERROR;
+  const char *zLocale;      /* Locale identifier - (eg. "jp_JP") */
+  const char *zName;        /* SQL Collation sequence name (eg. "japanese") */
+  UCollator *pUCollator;    /* ICU library collation object */
+  int rc;                   /* Return code from sqlite3_create_collation_x() */
+
+  assert(nArg==2 || nArg==3);
+  (void)nArg; /* Unused parameter */
+  zLocale = (const char *)sqlite3_value_text(apArg[0]);
+  zName = (const char *)sqlite3_value_text(apArg[1]);
+
+  if( !zLocale || !zName ){
+    return;
+  }
+
+  pUCollator = ucol_open(zLocale, &status);
+  if( !U_SUCCESS(status) ){
+    icuFunctionError(p, "ucol_open", status);
+    return;
+  }
+  assert(p);
+  if(nArg==3){
+    const char *zOption = (const char*)sqlite3_value_text(apArg[2]);
+    static const struct {
+       const char *zName;
+       UColAttributeValue val;
+    } aStrength[] = {
+      {  "PRIMARY",      UCOL_PRIMARY           },
+      {  "SECONDARY",    UCOL_SECONDARY         },
+      {  "TERTIARY",     UCOL_TERTIARY          },
+      {  "DEFAULT",      UCOL_DEFAULT_STRENGTH  },
+      {  "QUARTERNARY",  UCOL_QUATERNARY        },
+      {  "IDENTICAL",    UCOL_IDENTICAL         },
+    };
+    unsigned int i;
+    for(i=0; i<sizeof(aStrength)/sizeof(aStrength[0]); i++){
+      if( sqlite3_stricmp(zOption,aStrength[i].zName)==0 ){
+        ucol_setStrength(pUCollator, aStrength[i].val);
+        break;
+      }
+    }
+    if( i>=sizeof(aStrength)/sizeof(aStrength[0]) ){
+      sqlite3_str *pStr = sqlite3_str_new(sqlite3_context_db_handle(p));
+      sqlite3_str_appendf(pStr,
+         "unknown collation strength \"%s\" - should be one of:",
+         zOption);
+      for(i=0; i<sizeof(aStrength)/sizeof(aStrength[0]); i++){
+         sqlite3_str_appendf(pStr, " %s", aStrength[i].zName);
+      }
+      sqlite3_result_error(p, sqlite3_str_value(pStr), -1);
+      sqlite3_free(sqlite3_str_finish(pStr));
+      return;
+    }
+  }
+  rc = sqlite3_create_collation_v2(db, zName, SQLITE_UTF16, (void *)pUCollator,
+      icuCollationColl, icuCollationDel
+  );
+  if( rc!=SQLITE_OK ){
+    ucol_close(pUCollator);
+    sqlite3_result_error(p, "Error registering collation function", -1);
+  }
+}
+
+/*
+** Register the ICU extension functions with database db.
+*/
+SQLITE_PRIVATE int sqlite3IcuInit(sqlite3 *db){
+# define SQLITEICU_EXTRAFLAGS (SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS)
+  static const struct IcuScalar {
+    const char *zName;                        /* Function name */
+    unsigned char nArg;                       /* Number of arguments */
+    unsigned int enc;                         /* Optimal text encoding */
+    unsigned char iContext;                   /* sqlite3_user_data() context */
+    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  } scalars[] = {
+    {"icu_load_collation",2,SQLITE_UTF8|SQLITE_DIRECTONLY,1, icuLoadCollation},
+    {"icu_load_collation",3,SQLITE_UTF8|SQLITE_DIRECTONLY,1, icuLoadCollation},
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_ICU)
+    {"regexp", 2, SQLITE_ANY|SQLITEICU_EXTRAFLAGS,         0, icuRegexpFunc},
+    {"lower",  1, SQLITE_UTF16|SQLITEICU_EXTRAFLAGS,       0, icuCaseFunc16},
+    {"lower",  2, SQLITE_UTF16|SQLITEICU_EXTRAFLAGS,       0, icuCaseFunc16},
+    {"upper",  1, SQLITE_UTF16|SQLITEICU_EXTRAFLAGS,       1, icuCaseFunc16},
+    {"upper",  2, SQLITE_UTF16|SQLITEICU_EXTRAFLAGS,       1, icuCaseFunc16},
+    {"lower",  1, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        0, icuCaseFunc16},
+    {"lower",  2, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        0, icuCaseFunc16},
+    {"upper",  1, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        1, icuCaseFunc16},
+    {"upper",  2, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        1, icuCaseFunc16},
+    {"like",   2, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        0, icuLikeFunc},
+    {"like",   3, SQLITE_UTF8|SQLITEICU_EXTRAFLAGS,        0, icuLikeFunc},
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_ICU) */
+  };
+  int rc = SQLITE_OK;
+  int i;
+
+  for(i=0; rc==SQLITE_OK && i<(int)(sizeof(scalars)/sizeof(scalars[0])); i++){
+    const struct IcuScalar *p = &scalars[i];
+    rc = sqlite3_create_function(
+        db, p->zName, p->nArg, p->enc,
+        p->iContext ? (void*)db : (void*)0,
+        p->xFunc, 0, 0
+    );
+  }
+
+  return rc;
+}
+
+#ifndef SQLITE_CORE
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_icu_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi)
+  return sqlite3IcuInit(db);
+}
+#endif
+
+#endif
+
+/************** End of icu.c *************************************************/
+/************** Begin file fts3_icu.c ****************************************/
+/*
+** 2007 June 22
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file implements a tokenizer for fts3 based on the ICU library.
+*/
+/* #include "fts3Int.h" */
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+#ifdef SQLITE_ENABLE_ICU
+
+/* #include <assert.h> */
+/* #include <string.h> */
+/* #include "fts3_tokenizer.h" */
+
+#include <unicode/ubrk.h>
+/* #include <unicode/ucol.h> */
+/* #include <unicode/ustring.h> */
+#include <unicode/utf16.h>
+
+typedef struct IcuTokenizer IcuTokenizer;
+typedef struct IcuCursor IcuCursor;
+
+struct IcuTokenizer {
+  sqlite3_tokenizer base;
+  char *zLocale;
+};
+
+struct IcuCursor {
+  sqlite3_tokenizer_cursor base;
+
+  UBreakIterator *pIter;      /* ICU break-iterator object */
+  int nChar;                  /* Number of UChar elements in pInput */
+  UChar *aChar;               /* Copy of input using utf-16 encoding */
+  int *aOffset;               /* Offsets of each character in utf-8 input */
+
+  int nBuffer;
+  char *zBuffer;
+
+  int iToken;
+};
+
+/*
+** Create a new tokenizer instance.
+*/
+static int icuCreate(
+  int argc,                            /* Number of entries in argv[] */
+  const char * const *argv,            /* Tokenizer creation arguments */
+  sqlite3_tokenizer **ppTokenizer      /* OUT: Created tokenizer */
+){
+  IcuTokenizer *p;
+  int n = 0;
+
+  if( argc>0 ){
+    n = strlen(argv[0])+1;
+  }
+  p = (IcuTokenizer *)sqlite3_malloc64(sizeof(IcuTokenizer)+n);
+  if( !p ){
+    return SQLITE_NOMEM;
+  }
+  memset(p, 0, sizeof(IcuTokenizer));
+
+  if( n ){
+    p->zLocale = (char *)&p[1];
+    memcpy(p->zLocale, argv[0], n);
+  }
+
+  *ppTokenizer = (sqlite3_tokenizer *)p;
+
+  return SQLITE_OK;
+}
+
+/*
+** Destroy a tokenizer
+*/
+static int icuDestroy(sqlite3_tokenizer *pTokenizer){
+  IcuTokenizer *p = (IcuTokenizer *)pTokenizer;
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Prepare to begin tokenizing a particular string.  The input
+** string to be tokenized is pInput[0..nBytes-1].  A cursor
+** used to incrementally tokenize this string is returned in
+** *ppCursor.
+*/
+static int icuOpen(
+  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
+  const char *zInput,                    /* Input string */
+  int nInput,                            /* Length of zInput in bytes */
+  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
+){
+  IcuTokenizer *p = (IcuTokenizer *)pTokenizer;
+  IcuCursor *pCsr;
+
+  const int32_t opt = U_FOLD_CASE_DEFAULT;
+  UErrorCode status = U_ZERO_ERROR;
+  int nChar;
+
+  UChar32 c;
+  int iInput = 0;
+  int iOut = 0;
+
+  *ppCursor = 0;
+
+  if( zInput==0 ){
+    nInput = 0;
+    zInput = "";
+  }else if( nInput<0 ){
+    nInput = strlen(zInput);
+  }
+  nChar = nInput+1;
+  pCsr = (IcuCursor *)sqlite3_malloc64(
+      sizeof(IcuCursor) +                /* IcuCursor */
+      ((nChar+3)&~3) * sizeof(UChar) +   /* IcuCursor.aChar[] */
+      (nChar+1) * sizeof(int)            /* IcuCursor.aOffset[] */
+  );
+  if( !pCsr ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(IcuCursor));
+  pCsr->aChar = (UChar *)&pCsr[1];
+  pCsr->aOffset = (int *)&pCsr->aChar[(nChar+3)&~3];
+
+  pCsr->aOffset[iOut] = iInput;
+  U8_NEXT(zInput, iInput, nInput, c);
+  while( c>0 ){
+    int isError = 0;
+    c = u_foldCase(c, opt);
+    U16_APPEND(pCsr->aChar, iOut, nChar, c, isError);
+    if( isError ){
+      sqlite3_free(pCsr);
+      return SQLITE_ERROR;
+    }
+    pCsr->aOffset[iOut] = iInput;
+
+    if( iInput<nInput ){
+      U8_NEXT(zInput, iInput, nInput, c);
+    }else{
+      c = 0;
+    }
+  }
+
+  pCsr->pIter = ubrk_open(UBRK_WORD, p->zLocale, pCsr->aChar, iOut, &status);
+  if( !U_SUCCESS(status) ){
+    sqlite3_free(pCsr);
+    return SQLITE_ERROR;
+  }
+  pCsr->nChar = iOut;
+
+  ubrk_first(pCsr->pIter);
+  *ppCursor = (sqlite3_tokenizer_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** Close a tokenization cursor previously opened by a call to icuOpen().
+*/
+static int icuClose(sqlite3_tokenizer_cursor *pCursor){
+  IcuCursor *pCsr = (IcuCursor *)pCursor;
+  ubrk_close(pCsr->pIter);
+  sqlite3_free(pCsr->zBuffer);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** Extract the next token from a tokenization cursor.
+*/
+static int icuNext(
+  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by simpleOpen */
+  const char **ppToken,               /* OUT: *ppToken is the token text */
+  int *pnBytes,                       /* OUT: Number of bytes in token */
+  int *piStartOffset,                 /* OUT: Starting offset of token */
+  int *piEndOffset,                   /* OUT: Ending offset of token */
+  int *piPosition                     /* OUT: Position integer of token */
+){
+  IcuCursor *pCsr = (IcuCursor *)pCursor;
+
+  int iStart = 0;
+  int iEnd = 0;
+  int nByte = 0;
+
+  while( iStart==iEnd ){
+    UChar32 c;
+
+    iStart = ubrk_current(pCsr->pIter);
+    iEnd = ubrk_next(pCsr->pIter);
+    if( iEnd==UBRK_DONE ){
+      return SQLITE_DONE;
+    }
+
+    while( iStart<iEnd ){
+      int iWhite = iStart;
+      U16_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c);
+      if( u_isspace(c) ){
+        iStart = iWhite;
+      }else{
+        break;
+      }
+    }
+    assert(iStart<=iEnd);
+  }
+
+  do {
+    UErrorCode status = U_ZERO_ERROR;
+    if( nByte ){
+      char *zNew = sqlite3_realloc(pCsr->zBuffer, nByte);
+      if( !zNew ){
+        return SQLITE_NOMEM;
+      }
+      pCsr->zBuffer = zNew;
+      pCsr->nBuffer = nByte;
+    }
+
+    u_strToUTF8(
+        pCsr->zBuffer, pCsr->nBuffer, &nByte,    /* Output vars */
+        &pCsr->aChar[iStart], iEnd-iStart,       /* Input vars */
+        &status                                  /* Output success/failure */
+    );
+  } while( nByte>pCsr->nBuffer );
+
+  *ppToken = pCsr->zBuffer;
+  *pnBytes = nByte;
+  *piStartOffset = pCsr->aOffset[iStart];
+  *piEndOffset = pCsr->aOffset[iEnd];
+  *piPosition = pCsr->iToken++;
+
+  return SQLITE_OK;
+}
+
+/*
+** The set of routines that implement the simple tokenizer
+*/
+static const sqlite3_tokenizer_module icuTokenizerModule = {
+  0,                           /* iVersion    */
+  icuCreate,                   /* xCreate     */
+  icuDestroy,                  /* xCreate     */
+  icuOpen,                     /* xOpen       */
+  icuClose,                    /* xClose      */
+  icuNext,                     /* xNext       */
+  0,                           /* xLanguageid */
+};
+
+/*
+** Set *ppModule to point at the implementation of the ICU tokenizer.
+*/
+SQLITE_PRIVATE void sqlite3Fts3IcuTokenizerModule(
+  sqlite3_tokenizer_module const**ppModule
+){
+  *ppModule = &icuTokenizerModule;
+}
+
+#endif /* defined(SQLITE_ENABLE_ICU) */
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
+
+/************** End of fts3_icu.c ********************************************/
+/************** Begin file sqlite3rbu.c **************************************/
+/*
+** 2014 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+**
+** OVERVIEW
+**
+**  The RBU extension requires that the RBU update be packaged as an
+**  SQLite database. The tables it expects to find are described in
+**  sqlite3rbu.h.  Essentially, for each table xyz in the target database
+**  that the user wishes to write to, a corresponding data_xyz table is
+**  created in the RBU database and populated with one row for each row to
+**  update, insert or delete from the target table.
+**
+**  The update proceeds in three stages:
+**
+**  1) The database is updated. The modified database pages are written
+**     to a *-oal file. A *-oal file is just like a *-wal file, except
+**     that it is named "<database>-oal" instead of "<database>-wal".
+**     Because regular SQLite clients do not look for file named
+**     "<database>-oal", they go on using the original database in
+**     rollback mode while the *-oal file is being generated.
+**
+**     During this stage RBU does not update the database by writing
+**     directly to the target tables. Instead it creates "imposter"
+**     tables using the SQLITE_TESTCTRL_IMPOSTER interface that it uses
+**     to update each b-tree individually. All updates required by each
+**     b-tree are completed before moving on to the next, and all
+**     updates are done in sorted key order.
+**
+**  2) The "<database>-oal" file is moved to the equivalent "<database>-wal"
+**     location using a call to rename(2). Before doing this the RBU
+**     module takes an EXCLUSIVE lock on the database file, ensuring
+**     that there are no other active readers.
+**
+**     Once the EXCLUSIVE lock is released, any other database readers
+**     detect the new *-wal file and read the database in wal mode. At
+**     this point they see the new version of the database - including
+**     the updates made as part of the RBU update.
+**
+**  3) The new *-wal file is checkpointed. This proceeds in the same way
+**     as a regular database checkpoint, except that a single frame is
+**     checkpointed each time sqlite3rbu_step() is called. If the RBU
+**     handle is closed before the entire *-wal file is checkpointed,
+**     the checkpoint progress is saved in the RBU database and the
+**     checkpoint can be resumed by another RBU client at some point in
+**     the future.
+**
+** POTENTIAL PROBLEMS
+**
+**  The rename() call might not be portable. And RBU is not currently
+**  syncing the directory after renaming the file.
+**
+**  When state is saved, any commit to the *-oal file and the commit to
+**  the RBU update database are not atomic. So if the power fails at the
+**  wrong moment they might get out of sync. As the main database will be
+**  committed before the RBU update database this will likely either just
+**  pass unnoticed, or result in SQLITE_CONSTRAINT errors (due to UNIQUE
+**  constraint violations).
+**
+**  If some client does modify the target database mid RBU update, or some
+**  other error occurs, the RBU extension will keep throwing errors. It's
+**  not really clear how to get out of this state. The system could just
+**  by delete the RBU update database and *-oal file and have the device
+**  download the update again and start over.
+**
+**  At present, for an UPDATE, both the new.* and old.* records are
+**  collected in the rbu_xyz table. And for both UPDATEs and DELETEs all
+**  fields are collected.  This means we're probably writing a lot more
+**  data to disk when saving the state of an ongoing update to the RBU
+**  update database than is strictly necessary.
+**
+*/
+
+/* #include <assert.h> */
+/* #include <string.h> */
+/* #include <stdio.h> */
+
+/* #include "sqlite3.h" */
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_RBU)
+/************** Include sqlite3rbu.h in the middle of sqlite3rbu.c ***********/
+/************** Begin file sqlite3rbu.h **************************************/
+/*
+** 2014 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the public interface for the RBU extension.
+*/
+
+/*
+** SUMMARY
+**
+** Writing a transaction containing a large number of operations on
+** b-tree indexes that are collectively larger than the available cache
+** memory can be very inefficient.
+**
+** The problem is that in order to update a b-tree, the leaf page (at least)
+** containing the entry being inserted or deleted must be modified. If the
+** working set of leaves is larger than the available cache memory, then a
+** single leaf that is modified more than once as part of the transaction
+** may be loaded from or written to the persistent media multiple times.
+** Additionally, because the index updates are likely to be applied in
+** random order, access to pages within the database is also likely to be in
+** random order, which is itself quite inefficient.
+**
+** One way to improve the situation is to sort the operations on each index
+** by index key before applying them to the b-tree. This leads to an IO
+** pattern that resembles a single linear scan through the index b-tree,
+** and all but guarantees each modified leaf page is loaded and stored
+** exactly once. SQLite uses this trick to improve the performance of
+** CREATE INDEX commands. This extension allows it to be used to improve
+** the performance of large transactions on existing databases.
+**
+** Additionally, this extension allows the work involved in writing the
+** large transaction to be broken down into sub-transactions performed
+** sequentially by separate processes. This is useful if the system cannot
+** guarantee that a single update process will run for long enough to apply
+** the entire update, for example because the update is being applied on a
+** mobile device that is frequently rebooted. Even after the writer process
+** has committed one or more sub-transactions, other database clients continue
+** to read from the original database snapshot. In other words, partially
+** applied transactions are not visible to other clients.
+**
+** "RBU" stands for "Resumable Bulk Update". As in a large database update
+** transmitted via a wireless network to a mobile device. A transaction
+** applied using this extension is hence refered to as an "RBU update".
+**
+**
+** LIMITATIONS
+**
+** An "RBU update" transaction is subject to the following limitations:
+**
+**   * The transaction must consist of INSERT, UPDATE and DELETE operations
+**     only.
+**
+**   * INSERT statements may not use any default values.
+**
+**   * UPDATE and DELETE statements must identify their target rows by
+**     non-NULL PRIMARY KEY values. Rows with NULL values stored in PRIMARY
+**     KEY fields may not be updated or deleted. If the table being written
+**     has no PRIMARY KEY, affected rows must be identified by rowid.
+**
+**   * UPDATE statements may not modify PRIMARY KEY columns.
+**
+**   * No triggers will be fired.
+**
+**   * No foreign key violations are detected or reported.
+**
+**   * CHECK constraints are not enforced.
+**
+**   * No constraint handling mode except for "OR ROLLBACK" is supported.
+**
+**
+** PREPARATION
+**
+** An "RBU update" is stored as a separate SQLite database. A database
+** containing an RBU update is an "RBU database". For each table in the
+** target database to be updated, the RBU database should contain a table
+** named "data_<target name>" containing the same set of columns as the
+** target table, and one more - "rbu_control". The data_% table should
+** have no PRIMARY KEY or UNIQUE constraints, but each column should have
+** the same type as the corresponding column in the target database.
+** The "rbu_control" column should have no type at all. For example, if
+** the target database contains:
+**
+**   CREATE TABLE t1(a INTEGER PRIMARY KEY, b TEXT, c UNIQUE);
+**
+** Then the RBU database should contain:
+**
+**   CREATE TABLE data_t1(a INTEGER, b TEXT, c, rbu_control);
+**
+** The order of the columns in the data_% table does not matter.
+**
+** Instead of a regular table, the RBU database may also contain virtual
+** tables or views named using the data_<target> naming scheme.
+**
+** Instead of the plain data_<target> naming scheme, RBU database tables
+** may also be named data<integer>_<target>, where <integer> is any sequence
+** of zero or more numeric characters (0-9). This can be significant because
+** tables within the RBU database are always processed in order sorted by
+** name. By judicious selection of the <integer> portion of the names
+** of the RBU tables the user can therefore control the order in which they
+** are processed. This can be useful, for example, to ensure that "external
+** content" FTS4 tables are updated before their underlying content tables.
+**
+** If the target database table is a virtual table or a table that has no
+** PRIMARY KEY declaration, the data_% table must also contain a column
+** named "rbu_rowid". This column is mapped to the table's implicit primary
+** key column - "rowid". Virtual tables for which the "rowid" column does
+** not function like a primary key value cannot be updated using RBU. For
+** example, if the target db contains either of the following:
+**
+**   CREATE VIRTUAL TABLE x1 USING fts3(a, b);
+**   CREATE TABLE x1(a, b)
+**
+** then the RBU database should contain:
+**
+**   CREATE TABLE data_x1(a, b, rbu_rowid, rbu_control);
+**
+** All non-hidden columns (i.e. all columns matched by "SELECT *") of the
+** target table must be present in the input table. For virtual tables,
+** hidden columns are optional - they are updated by RBU if present in
+** the input table, or not otherwise. For example, to write to an fts4
+** table with a hidden languageid column such as:
+**
+**   CREATE VIRTUAL TABLE ft1 USING fts4(a, b, languageid='langid');
+**
+** Either of the following input table schemas may be used:
+**
+**   CREATE TABLE data_ft1(a, b, langid, rbu_rowid, rbu_control);
+**   CREATE TABLE data_ft1(a, b, rbu_rowid, rbu_control);
+**
+** For each row to INSERT into the target database as part of the RBU
+** update, the corresponding data_% table should contain a single record
+** with the "rbu_control" column set to contain integer value 0. The
+** other columns should be set to the values that make up the new record
+** to insert.
+**
+** If the target database table has an INTEGER PRIMARY KEY, it is not
+** possible to insert a NULL value into the IPK column. Attempting to
+** do so results in an SQLITE_MISMATCH error.
+**
+** For each row to DELETE from the target database as part of the RBU
+** update, the corresponding data_% table should contain a single record
+** with the "rbu_control" column set to contain integer value 1. The
+** real primary key values of the row to delete should be stored in the
+** corresponding columns of the data_% table. The values stored in the
+** other columns are not used.
+**
+** For each row to UPDATE from the target database as part of the RBU
+** update, the corresponding data_% table should contain a single record
+** with the "rbu_control" column set to contain a value of type text.
+** The real primary key values identifying the row to update should be
+** stored in the corresponding columns of the data_% table row, as should
+** the new values of all columns being update. The text value in the
+** "rbu_control" column must contain the same number of characters as
+** there are columns in the target database table, and must consist entirely
+** of 'x' and '.' characters (or in some special cases 'd' - see below). For
+** each column that is being updated, the corresponding character is set to
+** 'x'. For those that remain as they are, the corresponding character of the
+** rbu_control value should be set to '.'. For example, given the tables
+** above, the update statement:
+**
+**   UPDATE t1 SET c = 'usa' WHERE a = 4;
+**
+** is represented by the data_t1 row created by:
+**
+**   INSERT INTO data_t1(a, b, c, rbu_control) VALUES(4, NULL, 'usa', '..x');
+**
+** Instead of an 'x' character, characters of the rbu_control value specified
+** for UPDATEs may also be set to 'd'. In this case, instead of updating the
+** target table with the value stored in the corresponding data_% column, the
+** user-defined SQL function "rbu_delta()" is invoked and the result stored in
+** the target table column. rbu_delta() is invoked with two arguments - the
+** original value currently stored in the target table column and the
+** value specified in the data_xxx table.
+**
+** For example, this row:
+**
+**   INSERT INTO data_t1(a, b, c, rbu_control) VALUES(4, NULL, 'usa', '..d');
+**
+** is similar to an UPDATE statement such as:
+**
+**   UPDATE t1 SET c = rbu_delta(c, 'usa') WHERE a = 4;
+**
+** Finally, if an 'f' character appears in place of a 'd' or 's' in an
+** ota_control string, the contents of the data_xxx table column is assumed
+** to be a "fossil delta" - a patch to be applied to a blob value in the
+** format used by the fossil source-code management system. In this case
+** the existing value within the target database table must be of type BLOB.
+** It is replaced by the result of applying the specified fossil delta to
+** itself.
+**
+** If the target database table is a virtual table or a table with no PRIMARY
+** KEY, the rbu_control value should not include a character corresponding
+** to the rbu_rowid value. For example, this:
+**
+**   INSERT INTO data_ft1(a, b, rbu_rowid, rbu_control)
+**       VALUES(NULL, 'usa', 12, '.x');
+**
+** causes a result similar to:
+**
+**   UPDATE ft1 SET b = 'usa' WHERE rowid = 12;
+**
+** The data_xxx tables themselves should have no PRIMARY KEY declarations.
+** However, RBU is more efficient if reading the rows in from each data_xxx
+** table in "rowid" order is roughly the same as reading them sorted by
+** the PRIMARY KEY of the corresponding target database table. In other
+** words, rows should be sorted using the destination table PRIMARY KEY
+** fields before they are inserted into the data_xxx tables.
+**
+** USAGE
+**
+** The API declared below allows an application to apply an RBU update
+** stored on disk to an existing target database. Essentially, the
+** application:
+**
+**     1) Opens an RBU handle using the sqlite3rbu_open() function.
+**
+**     2) Registers any required virtual table modules with the database
+**        handle returned by sqlite3rbu_db(). Also, if required, register
+**        the rbu_delta() implementation.
+**
+**     3) Calls the sqlite3rbu_step() function one or more times on
+**        the new handle. Each call to sqlite3rbu_step() performs a single
+**        b-tree operation, so thousands of calls may be required to apply
+**        a complete update.
+**
+**     4) Calls sqlite3rbu_close() to close the RBU update handle. If
+**        sqlite3rbu_step() has been called enough times to completely
+**        apply the update to the target database, then the RBU database
+**        is marked as fully applied. Otherwise, the state of the RBU
+**        update application is saved in the RBU database for later
+**        resumption.
+**
+** See comments below for more detail on APIs.
+**
+** If an update is only partially applied to the target database by the
+** time sqlite3rbu_close() is called, various state information is saved
+** within the RBU database. This allows subsequent processes to automatically
+** resume the RBU update from where it left off.
+**
+** To remove all RBU extension state information, returning an RBU database
+** to its original contents, it is sufficient to drop all tables that begin
+** with the prefix "rbu_"
+**
+** DATABASE LOCKING
+**
+** An RBU update may not be applied to a database in WAL mode. Attempting
+** to do so is an error (SQLITE_ERROR).
+**
+** While an RBU handle is open, a SHARED lock may be held on the target
+** database file. This means it is possible for other clients to read the
+** database, but not to write it.
+**
+** If an RBU update is started and then suspended before it is completed,
+** then an external client writes to the database, then attempting to resume
+** the suspended RBU update is also an error (SQLITE_BUSY).
+*/
+
+#ifndef _SQLITE3RBU_H
+#define _SQLITE3RBU_H
+
+/* #include "sqlite3.h"              ** Required for error code definitions ** */
+
+#if 0
+extern "C" {
+#endif
+
+typedef struct sqlite3rbu sqlite3rbu;
+
+/*
+** Open an RBU handle.
+**
+** Argument zTarget is the path to the target database. Argument zRbu is
+** the path to the RBU database. Each call to this function must be matched
+** by a call to sqlite3rbu_close(). When opening the databases, RBU passes
+** the SQLITE_CONFIG_URI flag to sqlite3_open_v2(). So if either zTarget
+** or zRbu begin with "file:", it will be interpreted as an SQLite
+** database URI, not a regular file name.
+**
+** If the zState argument is passed a NULL value, the RBU extension stores
+** the current state of the update (how many rows have been updated, which
+** indexes are yet to be updated etc.) within the RBU database itself. This
+** can be convenient, as it means that the RBU application does not need to
+** organize removing a separate state file after the update is concluded.
+** Or, if zState is non-NULL, it must be a path to a database file in which
+** the RBU extension can store the state of the update.
+**
+** When resuming an RBU update, the zState argument must be passed the same
+** value as when the RBU update was started.
+**
+** Once the RBU update is finished, the RBU extension does not
+** automatically remove any zState database file, even if it created it.
+**
+** By default, RBU uses the default VFS to access the files on disk. To
+** use a VFS other than the default, an SQLite "file:" URI containing a
+** "vfs=..." option may be passed as the zTarget option.
+**
+** IMPORTANT NOTE FOR ZIPVFS USERS: The RBU extension works with all of
+** SQLite's built-in VFSs, including the multiplexor VFS. However it does
+** not work out of the box with zipvfs. Refer to the comment describing
+** the zipvfs_create_vfs() API below for details on using RBU with zipvfs.
+*/
+SQLITE_API sqlite3rbu *sqlite3rbu_open(
+  const char *zTarget,
+  const char *zRbu,
+  const char *zState
+);
+
+/*
+** Open an RBU handle to perform an RBU vacuum on database file zTarget.
+** An RBU vacuum is similar to SQLite's built-in VACUUM command, except
+** that it can be suspended and resumed like an RBU update.
+**
+** The second argument to this function identifies a database in which
+** to store the state of the RBU vacuum operation if it is suspended. The
+** first time sqlite3rbu_vacuum() is called, to start an RBU vacuum
+** operation, the state database should either not exist or be empty
+** (contain no tables). If an RBU vacuum is suspended by calling
+** sqlite3rbu_close() on the RBU handle before sqlite3rbu_step() has
+** returned SQLITE_DONE, the vacuum state is stored in the state database.
+** The vacuum can be resumed by calling this function to open a new RBU
+** handle specifying the same target and state databases.
+**
+** If the second argument passed to this function is NULL, then the
+** name of the state database is "<database>-vacuum", where <database>
+** is the name of the target database file. In this case, on UNIX, if the
+** state database is not already present in the file-system, it is created
+** with the same permissions as the target db is made.
+**
+** With an RBU vacuum, it is an SQLITE_MISUSE error if the name of the
+** state database ends with "-vactmp". This name is reserved for internal
+** use.
+**
+** This function does not delete the state database after an RBU vacuum
+** is completed, even if it created it. However, if the call to
+** sqlite3rbu_close() returns any value other than SQLITE_OK, the contents
+** of the state tables within the state database are zeroed. This way,
+** the next call to sqlite3rbu_vacuum() opens a handle that starts a
+** new RBU vacuum operation.
+**
+** As with sqlite3rbu_open(), Zipvfs users should rever to the comment
+** describing the sqlite3rbu_create_vfs() API function below for
+** a description of the complications associated with using RBU with
+** zipvfs databases.
+*/
+SQLITE_API sqlite3rbu *sqlite3rbu_vacuum(
+  const char *zTarget,
+  const char *zState
+);
+
+/*
+** Configure a limit for the amount of temp space that may be used by
+** the RBU handle passed as the first argument. The new limit is specified
+** in bytes by the second parameter. If it is positive, the limit is updated.
+** If the second parameter to this function is passed zero, then the limit
+** is removed entirely. If the second parameter is negative, the limit is
+** not modified (this is useful for querying the current limit).
+**
+** In all cases the returned value is the current limit in bytes (zero
+** indicates unlimited).
+**
+** If the temp space limit is exceeded during operation, an SQLITE_FULL
+** error is returned.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_temp_size_limit(sqlite3rbu*, sqlite3_int64);
+
+/*
+** Return the current amount of temp file space, in bytes, currently used by
+** the RBU handle passed as the only argument.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_temp_size(sqlite3rbu*);
+
+/*
+** Internally, each RBU connection uses a separate SQLite database
+** connection to access the target and rbu update databases. This
+** API allows the application direct access to these database handles.
+**
+** The first argument passed to this function must be a valid, open, RBU
+** handle. The second argument should be passed zero to access the target
+** database handle, or non-zero to access the rbu update database handle.
+** Accessing the underlying database handles may be useful in the
+** following scenarios:
+**
+**   * If any target tables are virtual tables, it may be necessary to
+**     call sqlite3_create_module() on the target database handle to
+**     register the required virtual table implementations.
+**
+**   * If the data_xxx tables in the RBU source database are virtual
+**     tables, the application may need to call sqlite3_create_module() on
+**     the rbu update db handle to any required virtual table
+**     implementations.
+**
+**   * If the application uses the "rbu_delta()" feature described above,
+**     it must use sqlite3_create_function() or similar to register the
+**     rbu_delta() implementation with the target database handle.
+**
+** If an error has occurred, either while opening or stepping the RBU object,
+** this function may return NULL. The error code and message may be collected
+** when sqlite3rbu_close() is called.
+**
+** Database handles returned by this function remain valid until the next
+** call to any sqlite3rbu_xxx() function other than sqlite3rbu_db().
+*/
+SQLITE_API sqlite3 *sqlite3rbu_db(sqlite3rbu*, int bRbu);
+
+/*
+** Do some work towards applying the RBU update to the target db.
+**
+** Return SQLITE_DONE if the update has been completely applied, or
+** SQLITE_OK if no error occurs but there remains work to do to apply
+** the RBU update. If an error does occur, some other error code is
+** returned.
+**
+** Once a call to sqlite3rbu_step() has returned a value other than
+** SQLITE_OK, all subsequent calls on the same RBU handle are no-ops
+** that immediately return the same value.
+*/
+SQLITE_API int sqlite3rbu_step(sqlite3rbu *pRbu);
+
+/*
+** Force RBU to save its state to disk.
+**
+** If a power failure or application crash occurs during an update, following
+** system recovery RBU may resume the update from the point at which the state
+** was last saved. In other words, from the most recent successful call to
+** sqlite3rbu_close() or this function.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+*/
+SQLITE_API int sqlite3rbu_savestate(sqlite3rbu *pRbu);
+
+/*
+** Close an RBU handle.
+**
+** If the RBU update has been completely applied, mark the RBU database
+** as fully applied. Otherwise, assuming no error has occurred, save the
+** current state of the RBU update appliation to the RBU database.
+**
+** If an error has already occurred as part of an sqlite3rbu_step()
+** or sqlite3rbu_open() call, or if one occurs within this function, an
+** SQLite error code is returned. Additionally, if pzErrmsg is not NULL,
+** *pzErrmsg may be set to point to a buffer containing a utf-8 formatted
+** English language error message. It is the responsibility of the caller to
+** eventually free any such buffer using sqlite3_free().
+**
+** Otherwise, if no error occurs, this function returns SQLITE_OK if the
+** update has been partially applied, or SQLITE_DONE if it has been
+** completely applied.
+*/
+SQLITE_API int sqlite3rbu_close(sqlite3rbu *pRbu, char **pzErrmsg);
+
+/*
+** Return the total number of key-value operations (inserts, deletes or
+** updates) that have been performed on the target database since the
+** current RBU update was started.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_progress(sqlite3rbu *pRbu);
+
+/*
+** Obtain permyriadage (permyriadage is to 10000 as percentage is to 100)
+** progress indications for the two stages of an RBU update. This API may
+** be useful for driving GUI progress indicators and similar.
+**
+** An RBU update is divided into two stages:
+**
+**   * Stage 1, in which changes are accumulated in an oal/wal file, and
+**   * Stage 2, in which the contents of the wal file are copied into the
+**     main database.
+**
+** The update is visible to non-RBU clients during stage 2. During stage 1
+** non-RBU reader clients may see the original database.
+**
+** If this API is called during stage 2 of the update, output variable
+** (*pnOne) is set to 10000 to indicate that stage 1 has finished and (*pnTwo)
+** to a value between 0 and 10000 to indicate the permyriadage progress of
+** stage 2. A value of 5000 indicates that stage 2 is half finished,
+** 9000 indicates that it is 90% finished, and so on.
+**
+** If this API is called during stage 1 of the update, output variable
+** (*pnTwo) is set to 0 to indicate that stage 2 has not yet started. The
+** value to which (*pnOne) is set depends on whether or not the RBU
+** database contains an "rbu_count" table. The rbu_count table, if it
+** exists, must contain the same columns as the following:
+**
+**   CREATE TABLE rbu_count(tbl TEXT PRIMARY KEY, cnt INTEGER) WITHOUT ROWID;
+**
+** There must be one row in the table for each source (data_xxx) table within
+** the RBU database. The 'tbl' column should contain the name of the source
+** table. The 'cnt' column should contain the number of rows within the
+** source table.
+**
+** If the rbu_count table is present and populated correctly and this
+** API is called during stage 1, the *pnOne output variable is set to the
+** permyriadage progress of the same stage. If the rbu_count table does
+** not exist, then (*pnOne) is set to -1 during stage 1. If the rbu_count
+** table exists but is not correctly populated, the value of the *pnOne
+** output variable during stage 1 is undefined.
+*/
+SQLITE_API void sqlite3rbu_bp_progress(sqlite3rbu *pRbu, int *pnOne, int*pnTwo);
+
+/*
+** Obtain an indication as to the current stage of an RBU update or vacuum.
+** This function always returns one of the SQLITE_RBU_STATE_XXX constants
+** defined in this file. Return values should be interpreted as follows:
+**
+** SQLITE_RBU_STATE_OAL:
+**   RBU is currently building a *-oal file. The next call to sqlite3rbu_step()
+**   may either add further data to the *-oal file, or compute data that will
+**   be added by a subsequent call.
+**
+** SQLITE_RBU_STATE_MOVE:
+**   RBU has finished building the *-oal file. The next call to sqlite3rbu_step()
+**   will move the *-oal file to the equivalent *-wal path. If the current
+**   operation is an RBU update, then the updated version of the database
+**   file will become visible to ordinary SQLite clients following the next
+**   call to sqlite3rbu_step().
+**
+** SQLITE_RBU_STATE_CHECKPOINT:
+**   RBU is currently performing an incremental checkpoint. The next call to
+**   sqlite3rbu_step() will copy a page of data from the *-wal file into
+**   the target database file.
+**
+** SQLITE_RBU_STATE_DONE:
+**   The RBU operation has finished. Any subsequent calls to sqlite3rbu_step()
+**   will immediately return SQLITE_DONE.
+**
+** SQLITE_RBU_STATE_ERROR:
+**   An error has occurred. Any subsequent calls to sqlite3rbu_step() will
+**   immediately return the SQLite error code associated with the error.
+*/
+#define SQLITE_RBU_STATE_OAL        1
+#define SQLITE_RBU_STATE_MOVE       2
+#define SQLITE_RBU_STATE_CHECKPOINT 3
+#define SQLITE_RBU_STATE_DONE       4
+#define SQLITE_RBU_STATE_ERROR      5
+
+SQLITE_API int sqlite3rbu_state(sqlite3rbu *pRbu);
+
+/*
+** As part of applying an RBU update or performing an RBU vacuum operation,
+** the system must at one point move the *-oal file to the equivalent *-wal
+** path. Normally, it does this by invoking POSIX function rename(2) directly.
+** Except on WINCE platforms, where it uses win32 API MoveFileW(). This
+** function may be used to register a callback that the RBU module will invoke
+** instead of one of these APIs.
+**
+** If a callback is registered with an RBU handle, it invokes it instead
+** of rename(2) when it needs to move a file within the file-system. The
+** first argument passed to the xRename() callback is a copy of the second
+** argument (pArg) passed to this function. The second is the full path
+** to the file to move and the third the full path to which it should be
+** moved. The callback function should return SQLITE_OK to indicate
+** success. If an error occurs, it should return an SQLite error code.
+** In this case the RBU operation will be abandoned and the error returned
+** to the RBU user.
+**
+** Passing a NULL pointer in place of the xRename argument to this function
+** restores the default behaviour.
+*/
+SQLITE_API void sqlite3rbu_rename_handler(
+  sqlite3rbu *pRbu,
+  void *pArg,
+  int (*xRename)(void *pArg, const char *zOld, const char *zNew)
+);
+
+
+/*
+** Create an RBU VFS named zName that accesses the underlying file-system
+** via existing VFS zParent. Or, if the zParent parameter is passed NULL,
+** then the new RBU VFS uses the default system VFS to access the file-system.
+** The new object is registered as a non-default VFS with SQLite before
+** returning.
+**
+** Part of the RBU implementation uses a custom VFS object. Usually, this
+** object is created and deleted automatically by RBU.
+**
+** The exception is for applications that also use zipvfs. In this case,
+** the custom VFS must be explicitly created by the user before the RBU
+** handle is opened. The RBU VFS should be installed so that the zipvfs
+** VFS uses the RBU VFS, which in turn uses any other VFS layers in use
+** (for example multiplexor) to access the file-system. For example,
+** to assemble an RBU enabled VFS stack that uses both zipvfs and
+** multiplexor (error checking omitted):
+**
+**     // Create a VFS named "multiplex" (not the default).
+**     sqlite3_multiplex_initialize(0, 0);
+**
+**     // Create an rbu VFS named "rbu" that uses multiplexor. If the
+**     // second argument were replaced with NULL, the "rbu" VFS would
+**     // access the file-system via the system default VFS, bypassing the
+**     // multiplexor.
+**     sqlite3rbu_create_vfs("rbu", "multiplex");
+**
+**     // Create a zipvfs VFS named "zipvfs" that uses rbu.
+**     zipvfs_create_vfs_v3("zipvfs", "rbu", 0, xCompressorAlgorithmDetector);
+**
+**     // Make zipvfs the default VFS.
+**     sqlite3_vfs_register(sqlite3_vfs_find("zipvfs"), 1);
+**
+** Because the default VFS created above includes a RBU functionality, it
+** may be used by RBU clients. Attempting to use RBU with a zipvfs VFS stack
+** that does not include the RBU layer results in an error.
+**
+** The overhead of adding the "rbu" VFS to the system is negligible for
+** non-RBU users. There is no harm in an application accessing the
+** file-system via "rbu" all the time, even if it only uses RBU functionality
+** occasionally.
+*/
+SQLITE_API int sqlite3rbu_create_vfs(const char *zName, const char *zParent);
+
+/*
+** Deregister and destroy an RBU vfs created by an earlier call to
+** sqlite3rbu_create_vfs().
+**
+** VFS objects are not reference counted. If a VFS object is destroyed
+** before all database handles that use it have been closed, the results
+** are undefined.
+*/
+SQLITE_API void sqlite3rbu_destroy_vfs(const char *zName);
+
+#if 0
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* _SQLITE3RBU_H */
+
+/************** End of sqlite3rbu.h ******************************************/
+/************** Continuing where we left off in sqlite3rbu.c *****************/
+
+#if defined(_WIN32_WCE)
+/* #include "windows.h" */
+#endif
+
+/* Maximum number of prepared UPDATE statements held by this module */
+#define SQLITE_RBU_UPDATE_CACHESIZE 16
+
+/* Delta checksums disabled by default.  Compile with -DRBU_ENABLE_DELTA_CKSUM
+** to enable checksum verification.
+*/
+#ifndef RBU_ENABLE_DELTA_CKSUM
+# define RBU_ENABLE_DELTA_CKSUM 0
+#endif
+
+/*
+** Swap two objects of type TYPE.
+*/
+#if !defined(SQLITE_AMALGAMATION)
+# define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
+#endif
+
+/*
+** Name of the URI option that causes RBU to take an exclusive lock as
+** part of the incremental checkpoint operation.
+*/
+#define RBU_EXCLUSIVE_CHECKPOINT "rbu_exclusive_checkpoint"
+
+
+/*
+** The rbu_state table is used to save the state of a partially applied
+** update so that it can be resumed later. The table consists of integer
+** keys mapped to values as follows:
+**
+** RBU_STATE_STAGE:
+**   May be set to integer values 1, 2, 4 or 5. As follows:
+**       1: the *-rbu file is currently under construction.
+**       2: the *-rbu file has been constructed, but not yet moved
+**          to the *-wal path.
+**       4: the checkpoint is underway.
+**       5: the rbu update has been checkpointed.
+**
+** RBU_STATE_TBL:
+**   Only valid if STAGE==1. The target database name of the table
+**   currently being written.
+**
+** RBU_STATE_IDX:
+**   Only valid if STAGE==1. The target database name of the index
+**   currently being written, or NULL if the main table is currently being
+**   updated.
+**
+** RBU_STATE_ROW:
+**   Only valid if STAGE==1. Number of rows already processed for the current
+**   table/index.
+**
+** RBU_STATE_PROGRESS:
+**   Trbul number of sqlite3rbu_step() calls made so far as part of this
+**   rbu update.
+**
+** RBU_STATE_CKPT:
+**   Valid if STAGE==4. The 64-bit checksum associated with the wal-index
+**   header created by recovering the *-wal file. This is used to detect
+**   cases when another client appends frames to the *-wal file in the
+**   middle of an incremental checkpoint (an incremental checkpoint cannot
+**   be continued if this happens).
+**
+** RBU_STATE_COOKIE:
+**   Valid if STAGE==1. The current change-counter cookie value in the
+**   target db file.
+**
+** RBU_STATE_OALSZ:
+**   Valid if STAGE==1. The size in bytes of the *-oal file.
+**
+** RBU_STATE_DATATBL:
+**   Only valid if STAGE==1. The RBU database name of the table
+**   currently being read.
+*/
+#define RBU_STATE_STAGE        1
+#define RBU_STATE_TBL          2
+#define RBU_STATE_IDX          3
+#define RBU_STATE_ROW          4
+#define RBU_STATE_PROGRESS     5
+#define RBU_STATE_CKPT         6
+#define RBU_STATE_COOKIE       7
+#define RBU_STATE_OALSZ        8
+#define RBU_STATE_PHASEONESTEP 9
+#define RBU_STATE_DATATBL     10
+
+#define RBU_STAGE_OAL         1
+#define RBU_STAGE_MOVE        2
+#define RBU_STAGE_CAPTURE     3
+#define RBU_STAGE_CKPT        4
+#define RBU_STAGE_DONE        5
+
+
+#define RBU_CREATE_STATE \
+  "CREATE TABLE IF NOT EXISTS %s.rbu_state(k INTEGER PRIMARY KEY, v)"
+
+typedef struct RbuFrame RbuFrame;
+typedef struct RbuObjIter RbuObjIter;
+typedef struct RbuState RbuState;
+typedef struct RbuSpan RbuSpan;
+typedef struct rbu_vfs rbu_vfs;
+typedef struct rbu_file rbu_file;
+typedef struct RbuUpdateStmt RbuUpdateStmt;
+
+#if !defined(SQLITE_AMALGAMATION)
+typedef unsigned int u32;
+typedef unsigned short u16;
+typedef unsigned char u8;
+typedef sqlite3_int64 i64;
+typedef sqlite3_uint64 u64;
+#endif
+
+/*
+** These values must match the values defined in wal.c for the equivalent
+** locks. These are not magic numbers as they are part of the SQLite file
+** format.
+*/
+#define WAL_LOCK_WRITE  0
+#define WAL_LOCK_CKPT   1
+#define WAL_LOCK_READ0  3
+
+#define SQLITE_FCNTL_RBUCNT    5149216
+
+/*
+** A structure to store values read from the rbu_state table in memory.
+*/
+struct RbuState {
+  int eStage;
+  char *zTbl;
+  char *zDataTbl;
+  char *zIdx;
+  i64 iWalCksum;
+  int nRow;
+  i64 nProgress;
+  u32 iCookie;
+  i64 iOalSz;
+  i64 nPhaseOneStep;
+};
+
+struct RbuUpdateStmt {
+  char *zMask;                    /* Copy of update mask used with pUpdate */
+  sqlite3_stmt *pUpdate;          /* Last update statement (or NULL) */
+  RbuUpdateStmt *pNext;
+};
+
+struct RbuSpan {
+  const char *zSpan;
+  int nSpan;
+};
+
+/*
+** An iterator of this type is used to iterate through all objects in
+** the target database that require updating. For each such table, the
+** iterator visits, in order:
+**
+**     * the table itself,
+**     * each index of the table (zero or more points to visit), and
+**     * a special "cleanup table" state.
+**
+** abIndexed:
+**   If the table has no indexes on it, abIndexed is set to NULL. Otherwise,
+**   it points to an array of flags nTblCol elements in size. The flag is
+**   set for each column that is either a part of the PK or a part of an
+**   index. Or clear otherwise.
+**
+**   If there are one or more partial indexes on the table, all fields of
+**   this array set set to 1. This is because in that case, the module has
+**   no way to tell which fields will be required to add and remove entries
+**   from the partial indexes.
+**
+*/
+struct RbuObjIter {
+  sqlite3_stmt *pTblIter;         /* Iterate through tables */
+  sqlite3_stmt *pIdxIter;         /* Index iterator */
+  int nTblCol;                    /* Size of azTblCol[] array */
+  char **azTblCol;                /* Array of unquoted target column names */
+  char **azTblType;               /* Array of target column types */
+  int *aiSrcOrder;                /* src table col -> target table col */
+  u8 *abTblPk;                    /* Array of flags, set on target PK columns */
+  u8 *abNotNull;                  /* Array of flags, set on NOT NULL columns */
+  u8 *abIndexed;                  /* Array of flags, set on indexed & PK cols */
+  int eType;                      /* Table type - an RBU_PK_XXX value */
+
+  /* Output variables. zTbl==0 implies EOF. */
+  int bCleanup;                   /* True in "cleanup" state */
+  const char *zTbl;               /* Name of target db table */
+  const char *zDataTbl;           /* Name of rbu db table (or null) */
+  const char *zIdx;               /* Name of target db index (or null) */
+  int iTnum;                      /* Root page of current object */
+  int iPkTnum;                    /* If eType==EXTERNAL, root of PK index */
+  int bUnique;                    /* Current index is unique */
+  int nIndex;                     /* Number of aux. indexes on table zTbl */
+
+  /* Statements created by rbuObjIterPrepareAll() */
+  int nCol;                       /* Number of columns in current object */
+  sqlite3_stmt *pSelect;          /* Source data */
+  sqlite3_stmt *pInsert;          /* Statement for INSERT operations */
+  sqlite3_stmt *pDelete;          /* Statement for DELETE ops */
+  sqlite3_stmt *pTmpInsert;       /* Insert into rbu_tmp_$zDataTbl */
+  int nIdxCol;
+  RbuSpan *aIdxCol;
+  char *zIdxSql;
+
+  /* Last UPDATE used (for PK b-tree updates only), or NULL. */
+  RbuUpdateStmt *pRbuUpdate;
+};
+
+/*
+** Values for RbuObjIter.eType
+**
+**     0: Table does not exist (error)
+**     1: Table has an implicit rowid.
+**     2: Table has an explicit IPK column.
+**     3: Table has an external PK index.
+**     4: Table is WITHOUT ROWID.
+**     5: Table is a virtual table.
+*/
+#define RBU_PK_NOTABLE        0
+#define RBU_PK_NONE           1
+#define RBU_PK_IPK            2
+#define RBU_PK_EXTERNAL       3
+#define RBU_PK_WITHOUT_ROWID  4
+#define RBU_PK_VTAB           5
+
+
+/*
+** Within the RBU_STAGE_OAL stage, each call to sqlite3rbu_step() performs
+** one of the following operations.
+*/
+#define RBU_INSERT     1          /* Insert on a main table b-tree */
+#define RBU_DELETE     2          /* Delete a row from a main table b-tree */
+#define RBU_REPLACE    3          /* Delete and then insert a row */
+#define RBU_IDX_DELETE 4          /* Delete a row from an aux. index b-tree */
+#define RBU_IDX_INSERT 5          /* Insert on an aux. index b-tree */
+
+#define RBU_UPDATE     6          /* Update a row in a main table b-tree */
+
+/*
+** A single step of an incremental checkpoint - frame iWalFrame of the wal
+** file should be copied to page iDbPage of the database file.
+*/
+struct RbuFrame {
+  u32 iDbPage;
+  u32 iWalFrame;
+};
+
+#ifndef UNUSED_PARAMETER
+/*
+** The following macros are used to suppress compiler warnings and to
+** make it clear to human readers when a function parameter is deliberately
+** left unused within the body of a function. This usually happens when
+** a function is called via a function pointer. For example the
+** implementation of an SQL aggregate step callback may not use the
+** parameter indicating the number of arguments passed to the aggregate,
+** if it knows that this is enforced elsewhere.
+**
+** When a function parameter is not used at all within the body of a function,
+** it is generally named "NotUsed" or "NotUsed2" to make things even clearer.
+** However, these macros may also be used to suppress warnings related to
+** parameters that may or may not be used depending on compilation options.
+** For example those parameters only used in assert() statements. In these
+** cases the parameters are named as per the usual conventions.
+*/
+#define UNUSED_PARAMETER(x) (void)(x)
+#define UNUSED_PARAMETER2(x,y) UNUSED_PARAMETER(x),UNUSED_PARAMETER(y)
+#endif
+
+/*
+** RBU handle.
+**
+** nPhaseOneStep:
+**   If the RBU database contains an rbu_count table, this value is set to
+**   a running estimate of the number of b-tree operations required to
+**   finish populating the *-oal file. This allows the sqlite3_bp_progress()
+**   API to calculate the permyriadage progress of populating the *-oal file
+**   using the formula:
+**
+**     permyriadage = (10000 * nProgress) / nPhaseOneStep
+**
+**   nPhaseOneStep is initialized to the sum of:
+**
+**     nRow * (nIndex + 1)
+**
+**   for all source tables in the RBU database, where nRow is the number
+**   of rows in the source table and nIndex the number of indexes on the
+**   corresponding target database table.
+**
+**   This estimate is accurate if the RBU update consists entirely of
+**   INSERT operations. However, it is inaccurate if:
+**
+**     * the RBU update contains any UPDATE operations. If the PK specified
+**       for an UPDATE operation does not exist in the target table, then
+**       no b-tree operations are required on index b-trees. Or if the
+**       specified PK does exist, then (nIndex*2) such operations are
+**       required (one delete and one insert on each index b-tree).
+**
+**     * the RBU update contains any DELETE operations for which the specified
+**       PK does not exist. In this case no operations are required on index
+**       b-trees.
+**
+**     * the RBU update contains REPLACE operations. These are similar to
+**       UPDATE operations.
+**
+**   nPhaseOneStep is updated to account for the conditions above during the
+**   first pass of each source table. The updated nPhaseOneStep value is
+**   stored in the rbu_state table if the RBU update is suspended.
+*/
+struct sqlite3rbu {
+  int eStage;                     /* Value of RBU_STATE_STAGE field */
+  sqlite3 *dbMain;                /* target database handle */
+  sqlite3 *dbRbu;                 /* rbu database handle */
+  char *zTarget;                  /* Path to target db */
+  char *zRbu;                     /* Path to rbu db */
+  char *zState;                   /* Path to state db (or NULL if zRbu) */
+  char zStateDb[5];               /* Db name for state ("stat" or "main") */
+  int rc;                         /* Value returned by last rbu_step() call */
+  char *zErrmsg;                  /* Error message if rc!=SQLITE_OK */
+  int nStep;                      /* Rows processed for current object */
+  sqlite3_int64 nProgress;        /* Rows processed for all objects */
+  RbuObjIter objiter;             /* Iterator for skipping through tbl/idx */
+  const char *zVfsName;           /* Name of automatically created rbu vfs */
+  rbu_file *pTargetFd;            /* File handle open on target db */
+  int nPagePerSector;             /* Pages per sector for pTargetFd */
+  i64 iOalSz;
+  i64 nPhaseOneStep;
+  void *pRenameArg;
+  int (*xRename)(void*, const char*, const char*);
+
+  /* The following state variables are used as part of the incremental
+  ** checkpoint stage (eStage==RBU_STAGE_CKPT). See comments surrounding
+  ** function rbuSetupCheckpoint() for details.  */
+  u32 iMaxFrame;                  /* Largest iWalFrame value in aFrame[] */
+  u32 mLock;
+  int nFrame;                     /* Entries in aFrame[] array */
+  int nFrameAlloc;                /* Allocated size of aFrame[] array */
+  RbuFrame *aFrame;
+  int pgsz;
+  u8 *aBuf;
+  i64 iWalCksum;
+  i64 szTemp;                     /* Current size of all temp files in use */
+  i64 szTempLimit;                /* Total size limit for temp files */
+
+  /* Used in RBU vacuum mode only */
+  int nRbu;                       /* Number of RBU VFS in the stack */
+  rbu_file *pRbuFd;               /* Fd for main db of dbRbu */
+};
+
+/*
+** An rbu VFS is implemented using an instance of this structure.
+**
+** Variable pRbu is only non-NULL for automatically created RBU VFS objects.
+** It is NULL for RBU VFS objects created explicitly using
+** sqlite3rbu_create_vfs(). It is used to track the total amount of temp
+** space used by the RBU handle.
+*/
+struct rbu_vfs {
+  sqlite3_vfs base;               /* rbu VFS shim methods */
+  sqlite3_vfs *pRealVfs;          /* Underlying VFS */
+  sqlite3_mutex *mutex;           /* Mutex to protect pMain */
+  sqlite3rbu *pRbu;               /* Owner RBU object */
+  rbu_file *pMain;                /* List of main db files */
+  rbu_file *pMainRbu;             /* List of main db files with pRbu!=0 */
+};
+
+/*
+** Each file opened by an rbu VFS is represented by an instance of
+** the following structure.
+**
+** If this is a temporary file (pRbu!=0 && flags&DELETE_ON_CLOSE), variable
+** "sz" is set to the current size of the database file.
+*/
+struct rbu_file {
+  sqlite3_file base;              /* sqlite3_file methods */
+  sqlite3_file *pReal;            /* Underlying file handle */
+  rbu_vfs *pRbuVfs;               /* Pointer to the rbu_vfs object */
+  sqlite3rbu *pRbu;               /* Pointer to rbu object (rbu target only) */
+  i64 sz;                         /* Size of file in bytes (temp only) */
+
+  int openFlags;                  /* Flags this file was opened with */
+  u32 iCookie;                    /* Cookie value for main db files */
+  u8 iWriteVer;                   /* "write-version" value for main db files */
+  u8 bNolock;                     /* True to fail EXCLUSIVE locks */
+
+  int nShm;                       /* Number of entries in apShm[] array */
+  char **apShm;                   /* Array of mmap'd *-shm regions */
+  char *zDel;                     /* Delete this when closing file */
+
+  const char *zWal;               /* Wal filename for this main db file */
+  rbu_file *pWalFd;               /* Wal file descriptor for this main db */
+  rbu_file *pMainNext;            /* Next MAIN_DB file */
+  rbu_file *pMainRbuNext;         /* Next MAIN_DB file with pRbu!=0 */
+};
+
+/*
+** True for an RBU vacuum handle, or false otherwise.
+*/
+#define rbuIsVacuum(p) ((p)->zTarget==0)
+
+
+/*************************************************************************
+** The following three functions, found below:
+**
+**   rbuDeltaGetInt()
+**   rbuDeltaChecksum()
+**   rbuDeltaApply()
+**
+** are lifted from the fossil source code (http://fossil-scm.org). They
+** are used to implement the scalar SQL function rbu_fossil_delta().
+*/
+
+/*
+** Read bytes from *pz and convert them into a positive integer.  When
+** finished, leave *pz pointing to the first character past the end of
+** the integer.  The *pLen parameter holds the length of the string
+** in *pz and is decremented once for each character in the integer.
+*/
+static unsigned int rbuDeltaGetInt(const char **pz, int *pLen){
+  static const signed char zValue[] = {
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+     0,  1,  2,  3,  4,  5,  6,  7,    8,  9, -1, -1, -1, -1, -1, -1,
+    -1, 10, 11, 12, 13, 14, 15, 16,   17, 18, 19, 20, 21, 22, 23, 24,
+    25, 26, 27, 28, 29, 30, 31, 32,   33, 34, 35, -1, -1, -1, -1, 36,
+    -1, 37, 38, 39, 40, 41, 42, 43,   44, 45, 46, 47, 48, 49, 50, 51,
+    52, 53, 54, 55, 56, 57, 58, 59,   60, 61, 62, -1, -1, -1, 63, -1,
+  };
+  unsigned int v = 0;
+  int c;
+  unsigned char *z = (unsigned char*)*pz;
+  unsigned char *zStart = z;
+  while( (c = zValue[0x7f&*(z++)])>=0 ){
+     v = (v<<6) + c;
+  }
+  z--;
+  *pLen -= (int)(z - zStart);
+  *pz = (char*)z;
+  return v;
+}
+
+#if RBU_ENABLE_DELTA_CKSUM
+/*
+** Compute a 32-bit checksum on the N-byte buffer.  Return the result.
+*/
+static unsigned int rbuDeltaChecksum(const char *zIn, size_t N){
+  const unsigned char *z = (const unsigned char *)zIn;
+  unsigned sum0 = 0;
+  unsigned sum1 = 0;
+  unsigned sum2 = 0;
+  unsigned sum3 = 0;
+  while(N >= 16){
+    sum0 += ((unsigned)z[0] + z[4] + z[8] + z[12]);
+    sum1 += ((unsigned)z[1] + z[5] + z[9] + z[13]);
+    sum2 += ((unsigned)z[2] + z[6] + z[10]+ z[14]);
+    sum3 += ((unsigned)z[3] + z[7] + z[11]+ z[15]);
+    z += 16;
+    N -= 16;
+  }
+  while(N >= 4){
+    sum0 += z[0];
+    sum1 += z[1];
+    sum2 += z[2];
+    sum3 += z[3];
+    z += 4;
+    N -= 4;
+  }
+  sum3 += (sum2 << 8) + (sum1 << 16) + (sum0 << 24);
+  switch(N){
+    case 3:   sum3 += (z[2] << 8);
+    case 2:   sum3 += (z[1] << 16);
+    case 1:   sum3 += (z[0] << 24);
+    default:  ;
+  }
+  return sum3;
+}
+#endif
+
+/*
+** Apply a delta.
+**
+** The output buffer should be big enough to hold the whole output
+** file and a NUL terminator at the end.  The delta_output_size()
+** routine will determine this size for you.
+**
+** The delta string should be null-terminated.  But the delta string
+** may contain embedded NUL characters (if the input and output are
+** binary files) so we also have to pass in the length of the delta in
+** the lenDelta parameter.
+**
+** This function returns the size of the output file in bytes (excluding
+** the final NUL terminator character).  Except, if the delta string is
+** malformed or intended for use with a source file other than zSrc,
+** then this routine returns -1.
+**
+** Refer to the delta_create() documentation above for a description
+** of the delta file format.
+*/
+static int rbuDeltaApply(
+  const char *zSrc,      /* The source or pattern file */
+  int lenSrc,            /* Length of the source file */
+  const char *zDelta,    /* Delta to apply to the pattern */
+  int lenDelta,          /* Length of the delta */
+  char *zOut             /* Write the output into this preallocated buffer */
+){
+  unsigned int limit;
+  unsigned int total = 0;
+#if RBU_ENABLE_DELTA_CKSUM
+  char *zOrigOut = zOut;
+#endif
+
+  limit = rbuDeltaGetInt(&zDelta, &lenDelta);
+  if( *zDelta!='\n' ){
+    /* ERROR: size integer not terminated by "\n" */
+    return -1;
+  }
+  zDelta++; lenDelta--;
+  while( *zDelta && lenDelta>0 ){
+    unsigned int cnt, ofst;
+    cnt = rbuDeltaGetInt(&zDelta, &lenDelta);
+    switch( zDelta[0] ){
+      case '@': {
+        zDelta++; lenDelta--;
+        ofst = rbuDeltaGetInt(&zDelta, &lenDelta);
+        if( lenDelta>0 && zDelta[0]!=',' ){
+          /* ERROR: copy command not terminated by ',' */
+          return -1;
+        }
+        zDelta++; lenDelta--;
+        total += cnt;
+        if( total>limit ){
+          /* ERROR: copy exceeds output file size */
+          return -1;
+        }
+        if( (int)(ofst+cnt) > lenSrc ){
+          /* ERROR: copy extends past end of input */
+          return -1;
+        }
+        memcpy(zOut, &zSrc[ofst], cnt);
+        zOut += cnt;
+        break;
+      }
+      case ':': {
+        zDelta++; lenDelta--;
+        total += cnt;
+        if( total>limit ){
+          /* ERROR:  insert command gives an output larger than predicted */
+          return -1;
+        }
+        if( (int)cnt>lenDelta ){
+          /* ERROR: insert count exceeds size of delta */
+          return -1;
+        }
+        memcpy(zOut, zDelta, cnt);
+        zOut += cnt;
+        zDelta += cnt;
+        lenDelta -= cnt;
+        break;
+      }
+      case ';': {
+        zDelta++; lenDelta--;
+        zOut[0] = 0;
+#if RBU_ENABLE_DELTA_CKSUM
+        if( cnt!=rbuDeltaChecksum(zOrigOut, total) ){
+          /* ERROR:  bad checksum */
+          return -1;
+        }
+#endif
+        if( total!=limit ){
+          /* ERROR: generated size does not match predicted size */
+          return -1;
+        }
+        return total;
+      }
+      default: {
+        /* ERROR: unknown delta operator */
+        return -1;
+      }
+    }
+  }
+  /* ERROR: unterminated delta */
+  return -1;
+}
+
+static int rbuDeltaOutputSize(const char *zDelta, int lenDelta){
+  int size;
+  size = rbuDeltaGetInt(&zDelta, &lenDelta);
+  if( *zDelta!='\n' ){
+    /* ERROR: size integer not terminated by "\n" */
+    return -1;
+  }
+  return size;
+}
+
+/*
+** End of code taken from fossil.
+*************************************************************************/
+
+/*
+** Implementation of SQL scalar function rbu_fossil_delta().
+**
+** This function applies a fossil delta patch to a blob. Exactly two
+** arguments must be passed to this function. The first is the blob to
+** patch and the second the patch to apply. If no error occurs, this
+** function returns the patched blob.
+*/
+static void rbuFossilDeltaFunc(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  const char *aDelta;
+  int nDelta;
+  const char *aOrig;
+  int nOrig;
+
+  int nOut;
+  int nOut2;
+  char *aOut;
+
+  assert( argc==2 );
+  UNUSED_PARAMETER(argc);
+
+  nOrig = sqlite3_value_bytes(argv[0]);
+  aOrig = (const char*)sqlite3_value_blob(argv[0]);
+  nDelta = sqlite3_value_bytes(argv[1]);
+  aDelta = (const char*)sqlite3_value_blob(argv[1]);
+
+  /* Figure out the size of the output */
+  nOut = rbuDeltaOutputSize(aDelta, nDelta);
+  if( nOut<0 ){
+    sqlite3_result_error(context, "corrupt fossil delta", -1);
+    return;
+  }
+
+  aOut = sqlite3_malloc(nOut+1);
+  if( aOut==0 ){
+    sqlite3_result_error_nomem(context);
+  }else{
+    nOut2 = rbuDeltaApply(aOrig, nOrig, aDelta, nDelta, aOut);
+    if( nOut2!=nOut ){
+      sqlite3_free(aOut);
+      sqlite3_result_error(context, "corrupt fossil delta", -1);
+    }else{
+      sqlite3_result_blob(context, aOut, nOut, sqlite3_free);
+    }
+  }
+}
+
+
+/*
+** Prepare the SQL statement in buffer zSql against database handle db.
+** If successful, set *ppStmt to point to the new statement and return
+** SQLITE_OK.
+**
+** Otherwise, if an error does occur, set *ppStmt to NULL and return
+** an SQLite error code. Additionally, set output variable *pzErrmsg to
+** point to a buffer containing an error message. It is the responsibility
+** of the caller to (eventually) free this buffer using sqlite3_free().
+*/
+static int prepareAndCollectError(
+  sqlite3 *db,
+  sqlite3_stmt **ppStmt,
+  char **pzErrmsg,
+  const char *zSql
+){
+  int rc = sqlite3_prepare_v2(db, zSql, -1, ppStmt, 0);
+  if( rc!=SQLITE_OK ){
+    *pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+    *ppStmt = 0;
+  }
+  return rc;
+}
+
+/*
+** Reset the SQL statement passed as the first argument. Return a copy
+** of the value returned by sqlite3_reset().
+**
+** If an error has occurred, then set *pzErrmsg to point to a buffer
+** containing an error message. It is the responsibility of the caller
+** to eventually free this buffer using sqlite3_free().
+*/
+static int resetAndCollectError(sqlite3_stmt *pStmt, char **pzErrmsg){
+  int rc = sqlite3_reset(pStmt);
+  if( rc!=SQLITE_OK ){
+    *pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(sqlite3_db_handle(pStmt)));
+  }
+  return rc;
+}
+
+/*
+** Unless it is NULL, argument zSql points to a buffer allocated using
+** sqlite3_malloc containing an SQL statement. This function prepares the SQL
+** statement against database db and frees the buffer. If statement
+** compilation is successful, *ppStmt is set to point to the new statement
+** handle and SQLITE_OK is returned.
+**
+** Otherwise, if an error occurs, *ppStmt is set to NULL and an error code
+** returned. In this case, *pzErrmsg may also be set to point to an error
+** message. It is the responsibility of the caller to free this error message
+** buffer using sqlite3_free().
+**
+** If argument zSql is NULL, this function assumes that an OOM has occurred.
+** In this case SQLITE_NOMEM is returned and *ppStmt set to NULL.
+*/
+static int prepareFreeAndCollectError(
+  sqlite3 *db,
+  sqlite3_stmt **ppStmt,
+  char **pzErrmsg,
+  char *zSql
+){
+  int rc;
+  assert( *pzErrmsg==0 );
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+    *ppStmt = 0;
+  }else{
+    rc = prepareAndCollectError(db, ppStmt, pzErrmsg, zSql);
+    sqlite3_free(zSql);
+  }
+  return rc;
+}
+
+/*
+** Free the RbuObjIter.azTblCol[] and RbuObjIter.abTblPk[] arrays allocated
+** by an earlier call to rbuObjIterCacheTableInfo().
+*/
+static void rbuObjIterFreeCols(RbuObjIter *pIter){
+  int i;
+  for(i=0; i<pIter->nTblCol; i++){
+    sqlite3_free(pIter->azTblCol[i]);
+    sqlite3_free(pIter->azTblType[i]);
+  }
+  sqlite3_free(pIter->azTblCol);
+  pIter->azTblCol = 0;
+  pIter->azTblType = 0;
+  pIter->aiSrcOrder = 0;
+  pIter->abTblPk = 0;
+  pIter->abNotNull = 0;
+  pIter->nTblCol = 0;
+  pIter->eType = 0;               /* Invalid value */
+}
+
+/*
+** Finalize all statements and free all allocations that are specific to
+** the current object (table/index pair).
+*/
+static void rbuObjIterClearStatements(RbuObjIter *pIter){
+  RbuUpdateStmt *pUp;
+
+  sqlite3_finalize(pIter->pSelect);
+  sqlite3_finalize(pIter->pInsert);
+  sqlite3_finalize(pIter->pDelete);
+  sqlite3_finalize(pIter->pTmpInsert);
+  pUp = pIter->pRbuUpdate;
+  while( pUp ){
+    RbuUpdateStmt *pTmp = pUp->pNext;
+    sqlite3_finalize(pUp->pUpdate);
+    sqlite3_free(pUp);
+    pUp = pTmp;
+  }
+  sqlite3_free(pIter->aIdxCol);
+  sqlite3_free(pIter->zIdxSql);
+
+  pIter->pSelect = 0;
+  pIter->pInsert = 0;
+  pIter->pDelete = 0;
+  pIter->pRbuUpdate = 0;
+  pIter->pTmpInsert = 0;
+  pIter->nCol = 0;
+  pIter->nIdxCol = 0;
+  pIter->aIdxCol = 0;
+  pIter->zIdxSql = 0;
+}
+
+/*
+** Clean up any resources allocated as part of the iterator object passed
+** as the only argument.
+*/
+static void rbuObjIterFinalize(RbuObjIter *pIter){
+  rbuObjIterClearStatements(pIter);
+  sqlite3_finalize(pIter->pTblIter);
+  sqlite3_finalize(pIter->pIdxIter);
+  rbuObjIterFreeCols(pIter);
+  memset(pIter, 0, sizeof(RbuObjIter));
+}
+
+/*
+** Advance the iterator to the next position.
+**
+** If no error occurs, SQLITE_OK is returned and the iterator is left
+** pointing to the next entry. Otherwise, an error code and message is
+** left in the RBU handle passed as the first argument. A copy of the
+** error code is returned.
+*/
+static int rbuObjIterNext(sqlite3rbu *p, RbuObjIter *pIter){
+  int rc = p->rc;
+  if( rc==SQLITE_OK ){
+
+    /* Free any SQLite statements used while processing the previous object */
+    rbuObjIterClearStatements(pIter);
+    if( pIter->zIdx==0 ){
+      rc = sqlite3_exec(p->dbMain,
+          "DROP TRIGGER IF EXISTS temp.rbu_insert_tr;"
+          "DROP TRIGGER IF EXISTS temp.rbu_update1_tr;"
+          "DROP TRIGGER IF EXISTS temp.rbu_update2_tr;"
+          "DROP TRIGGER IF EXISTS temp.rbu_delete_tr;"
+          , 0, 0, &p->zErrmsg
+      );
+    }
+
+    if( rc==SQLITE_OK ){
+      if( pIter->bCleanup ){
+        rbuObjIterFreeCols(pIter);
+        pIter->bCleanup = 0;
+        rc = sqlite3_step(pIter->pTblIter);
+        if( rc!=SQLITE_ROW ){
+          rc = resetAndCollectError(pIter->pTblIter, &p->zErrmsg);
+          pIter->zTbl = 0;
+          pIter->zDataTbl = 0;
+        }else{
+          pIter->zTbl = (const char*)sqlite3_column_text(pIter->pTblIter, 0);
+          pIter->zDataTbl = (const char*)sqlite3_column_text(pIter->pTblIter,1);
+          rc = (pIter->zDataTbl && pIter->zTbl) ? SQLITE_OK : SQLITE_NOMEM;
+        }
+      }else{
+        if( pIter->zIdx==0 ){
+          sqlite3_stmt *pIdx = pIter->pIdxIter;
+          rc = sqlite3_bind_text(pIdx, 1, pIter->zTbl, -1, SQLITE_STATIC);
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3_step(pIter->pIdxIter);
+          if( rc!=SQLITE_ROW ){
+            rc = resetAndCollectError(pIter->pIdxIter, &p->zErrmsg);
+            pIter->bCleanup = 1;
+            pIter->zIdx = 0;
+          }else{
+            pIter->zIdx = (const char*)sqlite3_column_text(pIter->pIdxIter, 0);
+            pIter->iTnum = sqlite3_column_int(pIter->pIdxIter, 1);
+            pIter->bUnique = sqlite3_column_int(pIter->pIdxIter, 2);
+            rc = pIter->zIdx ? SQLITE_OK : SQLITE_NOMEM;
+          }
+        }
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    rbuObjIterFinalize(pIter);
+    p->rc = rc;
+  }
+  return rc;
+}
+
+
+/*
+** The implementation of the rbu_target_name() SQL function. This function
+** accepts one or two arguments. The first argument is the name of a table -
+** the name of a table in the RBU database.  The second, if it is present, is 1
+** for a view or 0 for a table.
+**
+** For a non-vacuum RBU handle, if the table name matches the pattern:
+**
+**     data[0-9]_<name>
+**
+** where <name> is any sequence of 1 or more characters, <name> is returned.
+** Otherwise, if the only argument does not match the above pattern, an SQL
+** NULL is returned.
+**
+**     "data_t1"     -> "t1"
+**     "data0123_t2" -> "t2"
+**     "dataAB_t3"   -> NULL
+**
+** For an rbu vacuum handle, a copy of the first argument is returned if
+** the second argument is either missing or 0 (not a view).
+*/
+static void rbuTargetNameFunc(
+  sqlite3_context *pCtx,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3rbu *p = sqlite3_user_data(pCtx);
+  const char *zIn;
+  assert( argc==1 || argc==2 );
+
+  zIn = (const char*)sqlite3_value_text(argv[0]);
+  if( zIn ){
+    if( rbuIsVacuum(p) ){
+      assert( argc==2 || argc==1 );
+      if( argc==1 || 0==sqlite3_value_int(argv[1]) ){
+        sqlite3_result_text(pCtx, zIn, -1, SQLITE_STATIC);
+      }
+    }else{
+      if( strlen(zIn)>4 && memcmp("data", zIn, 4)==0 ){
+        int i;
+        for(i=4; zIn[i]>='0' && zIn[i]<='9'; i++);
+        if( zIn[i]=='_' && zIn[i+1] ){
+          sqlite3_result_text(pCtx, &zIn[i+1], -1, SQLITE_STATIC);
+        }
+      }
+    }
+  }
+}
+
+/*
+** Initialize the iterator structure passed as the second argument.
+**
+** If no error occurs, SQLITE_OK is returned and the iterator is left
+** pointing to the first entry. Otherwise, an error code and message is
+** left in the RBU handle passed as the first argument. A copy of the
+** error code is returned.
+*/
+static int rbuObjIterFirst(sqlite3rbu *p, RbuObjIter *pIter){
+  int rc;
+  memset(pIter, 0, sizeof(RbuObjIter));
+
+  rc = prepareFreeAndCollectError(p->dbRbu, &pIter->pTblIter, &p->zErrmsg,
+    sqlite3_mprintf(
+      "SELECT rbu_target_name(name, type='view') AS target, name "
+      "FROM sqlite_schema "
+      "WHERE type IN ('table', 'view') AND target IS NOT NULL "
+      " %s "
+      "ORDER BY name"
+  , rbuIsVacuum(p) ? "AND rootpage!=0 AND rootpage IS NOT NULL" : ""));
+
+  if( rc==SQLITE_OK ){
+    rc = prepareAndCollectError(p->dbMain, &pIter->pIdxIter, &p->zErrmsg,
+        "SELECT name, rootpage, sql IS NULL OR substr(8, 6)=='UNIQUE' "
+        "  FROM main.sqlite_schema "
+        "  WHERE type='index' AND tbl_name = ?"
+    );
+  }
+
+  pIter->bCleanup = 1;
+  p->rc = rc;
+  return rbuObjIterNext(p, pIter);
+}
+
+/*
+** This is a wrapper around "sqlite3_mprintf(zFmt, ...)". If an OOM occurs,
+** an error code is stored in the RBU handle passed as the first argument.
+**
+** If an error has already occurred (p->rc is already set to something other
+** than SQLITE_OK), then this function returns NULL without modifying the
+** stored error code. In this case it still calls sqlite3_free() on any
+** printf() parameters associated with %z conversions.
+*/
+static char *rbuMPrintf(sqlite3rbu *p, const char *zFmt, ...){
+  char *zSql = 0;
+  va_list ap;
+  va_start(ap, zFmt);
+  zSql = sqlite3_vmprintf(zFmt, ap);
+  if( p->rc==SQLITE_OK ){
+    if( zSql==0 ) p->rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_free(zSql);
+    zSql = 0;
+  }
+  va_end(ap);
+  return zSql;
+}
+
+/*
+** Argument zFmt is a sqlite3_mprintf() style format string. The trailing
+** arguments are the usual subsitution values. This function performs
+** the printf() style substitutions and executes the result as an SQL
+** statement on the RBU handles database.
+**
+** If an error occurs, an error code and error message is stored in the
+** RBU handle. If an error has already occurred when this function is
+** called, it is a no-op.
+*/
+static int rbuMPrintfExec(sqlite3rbu *p, sqlite3 *db, const char *zFmt, ...){
+  va_list ap;
+  char *zSql;
+  va_start(ap, zFmt);
+  zSql = sqlite3_vmprintf(zFmt, ap);
+  if( p->rc==SQLITE_OK ){
+    if( zSql==0 ){
+      p->rc = SQLITE_NOMEM;
+    }else{
+      p->rc = sqlite3_exec(db, zSql, 0, 0, &p->zErrmsg);
+    }
+  }
+  sqlite3_free(zSql);
+  va_end(ap);
+  return p->rc;
+}
+
+/*
+** Attempt to allocate and return a pointer to a zeroed block of nByte
+** bytes.
+**
+** If an error (i.e. an OOM condition) occurs, return NULL and leave an
+** error code in the rbu handle passed as the first argument. Or, if an
+** error has already occurred when this function is called, return NULL
+** immediately without attempting the allocation or modifying the stored
+** error code.
+*/
+static void *rbuMalloc(sqlite3rbu *p, sqlite3_int64 nByte){
+  void *pRet = 0;
+  if( p->rc==SQLITE_OK ){
+    assert( nByte>0 );
+    pRet = sqlite3_malloc64(nByte);
+    if( pRet==0 ){
+      p->rc = SQLITE_NOMEM;
+    }else{
+      memset(pRet, 0, nByte);
+    }
+  }
+  return pRet;
+}
+
+
+/*
+** Allocate and zero the pIter->azTblCol[] and abTblPk[] arrays so that
+** there is room for at least nCol elements. If an OOM occurs, store an
+** error code in the RBU handle passed as the first argument.
+*/
+static void rbuAllocateIterArrays(sqlite3rbu *p, RbuObjIter *pIter, int nCol){
+  sqlite3_int64 nByte = (2*sizeof(char*) + sizeof(int) + 3*sizeof(u8)) * nCol;
+  char **azNew;
+
+  azNew = (char**)rbuMalloc(p, nByte);
+  if( azNew ){
+    pIter->azTblCol = azNew;
+    pIter->azTblType = &azNew[nCol];
+    pIter->aiSrcOrder = (int*)&pIter->azTblType[nCol];
+    pIter->abTblPk = (u8*)&pIter->aiSrcOrder[nCol];
+    pIter->abNotNull = (u8*)&pIter->abTblPk[nCol];
+    pIter->abIndexed = (u8*)&pIter->abNotNull[nCol];
+  }
+}
+
+/*
+** The first argument must be a nul-terminated string. This function
+** returns a copy of the string in memory obtained from sqlite3_malloc().
+** It is the responsibility of the caller to eventually free this memory
+** using sqlite3_free().
+**
+** If an OOM condition is encountered when attempting to allocate memory,
+** output variable (*pRc) is set to SQLITE_NOMEM before returning. Otherwise,
+** if the allocation succeeds, (*pRc) is left unchanged.
+*/
+static char *rbuStrndup(const char *zStr, int *pRc){
+  char *zRet = 0;
+
+  if( *pRc==SQLITE_OK ){
+    if( zStr ){
+      size_t nCopy = strlen(zStr) + 1;
+      zRet = (char*)sqlite3_malloc64(nCopy);
+      if( zRet ){
+        memcpy(zRet, zStr, nCopy);
+      }else{
+        *pRc = SQLITE_NOMEM;
+      }
+    }
+  }
+
+  return zRet;
+}
+
+/*
+** Finalize the statement passed as the second argument.
+**
+** If the sqlite3_finalize() call indicates that an error occurs, and the
+** rbu handle error code is not already set, set the error code and error
+** message accordingly.
+*/
+static void rbuFinalize(sqlite3rbu *p, sqlite3_stmt *pStmt){
+  sqlite3 *db = sqlite3_db_handle(pStmt);
+  int rc = sqlite3_finalize(pStmt);
+  if( p->rc==SQLITE_OK && rc!=SQLITE_OK ){
+    p->rc = rc;
+    p->zErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+  }
+}
+
+/* Determine the type of a table.
+**
+**   peType is of type (int*), a pointer to an output parameter of type
+**   (int). This call sets the output parameter as follows, depending
+**   on the type of the table specified by parameters dbName and zTbl.
+**
+**     RBU_PK_NOTABLE:       No such table.
+**     RBU_PK_NONE:          Table has an implicit rowid.
+**     RBU_PK_IPK:           Table has an explicit IPK column.
+**     RBU_PK_EXTERNAL:      Table has an external PK index.
+**     RBU_PK_WITHOUT_ROWID: Table is WITHOUT ROWID.
+**     RBU_PK_VTAB:          Table is a virtual table.
+**
+**   Argument *piPk is also of type (int*), and also points to an output
+**   parameter. Unless the table has an external primary key index
+**   (i.e. unless *peType is set to 3), then *piPk is set to zero. Or,
+**   if the table does have an external primary key index, then *piPk
+**   is set to the root page number of the primary key index before
+**   returning.
+**
+** ALGORITHM:
+**
+**   if( no entry exists in sqlite_schema ){
+**     return RBU_PK_NOTABLE
+**   }else if( sql for the entry starts with "CREATE VIRTUAL" ){
+**     return RBU_PK_VTAB
+**   }else if( "PRAGMA index_list()" for the table contains a "pk" index ){
+**     if( the index that is the pk exists in sqlite_schema ){
+**       *piPK = rootpage of that index.
+**       return RBU_PK_EXTERNAL
+**     }else{
+**       return RBU_PK_WITHOUT_ROWID
+**     }
+**   }else if( "PRAGMA table_info()" lists one or more "pk" columns ){
+**     return RBU_PK_IPK
+**   }else{
+**     return RBU_PK_NONE
+**   }
+*/
+static void rbuTableType(
+  sqlite3rbu *p,
+  const char *zTab,
+  int *peType,
+  int *piTnum,
+  int *piPk
+){
+  /*
+  ** 0) SELECT count(*) FROM sqlite_schema where name=%Q AND IsVirtual(%Q)
+  ** 1) PRAGMA index_list = ?
+  ** 2) SELECT count(*) FROM sqlite_schema where name=%Q
+  ** 3) PRAGMA table_info = ?
+  */
+  sqlite3_stmt *aStmt[4] = {0, 0, 0, 0};
+
+  *peType = RBU_PK_NOTABLE;
+  *piPk = 0;
+
+  assert( p->rc==SQLITE_OK );
+  p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[0], &p->zErrmsg,
+    sqlite3_mprintf(
+          "SELECT "
+          " (sql COLLATE nocase BETWEEN 'CREATE VIRTUAL' AND 'CREATE VIRTUAM'),"
+          " rootpage"
+          "  FROM sqlite_schema"
+          " WHERE name=%Q", zTab
+  ));
+  if( p->rc!=SQLITE_OK || sqlite3_step(aStmt[0])!=SQLITE_ROW ){
+    /* Either an error, or no such table. */
+    goto rbuTableType_end;
+  }
+  if( sqlite3_column_int(aStmt[0], 0) ){
+    *peType = RBU_PK_VTAB;                     /* virtual table */
+    goto rbuTableType_end;
+  }
+  *piTnum = sqlite3_column_int(aStmt[0], 1);
+
+  p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[1], &p->zErrmsg,
+    sqlite3_mprintf("PRAGMA index_list=%Q",zTab)
+  );
+  if( p->rc ) goto rbuTableType_end;
+  while( sqlite3_step(aStmt[1])==SQLITE_ROW ){
+    const u8 *zOrig = sqlite3_column_text(aStmt[1], 3);
+    const u8 *zIdx = sqlite3_column_text(aStmt[1], 1);
+    if( zOrig && zIdx && zOrig[0]=='p' ){
+      p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[2], &p->zErrmsg,
+          sqlite3_mprintf(
+            "SELECT rootpage FROM sqlite_schema WHERE name = %Q", zIdx
+      ));
+      if( p->rc==SQLITE_OK ){
+        if( sqlite3_step(aStmt[2])==SQLITE_ROW ){
+          *piPk = sqlite3_column_int(aStmt[2], 0);
+          *peType = RBU_PK_EXTERNAL;
+        }else{
+          *peType = RBU_PK_WITHOUT_ROWID;
+        }
+      }
+      goto rbuTableType_end;
+    }
+  }
+
+  p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[3], &p->zErrmsg,
+    sqlite3_mprintf("PRAGMA table_info=%Q",zTab)
+  );
+  if( p->rc==SQLITE_OK ){
+    while( sqlite3_step(aStmt[3])==SQLITE_ROW ){
+      if( sqlite3_column_int(aStmt[3],5)>0 ){
+        *peType = RBU_PK_IPK;                /* explicit IPK column */
+        goto rbuTableType_end;
+      }
+    }
+    *peType = RBU_PK_NONE;
+  }
+
+rbuTableType_end: {
+    unsigned int i;
+    for(i=0; i<sizeof(aStmt)/sizeof(aStmt[0]); i++){
+      rbuFinalize(p, aStmt[i]);
+    }
+  }
+}
+
+/*
+** This is a helper function for rbuObjIterCacheTableInfo(). It populates
+** the pIter->abIndexed[] array.
+*/
+static void rbuObjIterCacheIndexedCols(sqlite3rbu *p, RbuObjIter *pIter){
+  sqlite3_stmt *pList = 0;
+  int bIndex = 0;
+
+  if( p->rc==SQLITE_OK ){
+    memcpy(pIter->abIndexed, pIter->abTblPk, sizeof(u8)*pIter->nTblCol);
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pList, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.index_list = %Q", pIter->zTbl)
+    );
+  }
+
+  pIter->nIndex = 0;
+  while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pList) ){
+    const char *zIdx = (const char*)sqlite3_column_text(pList, 1);
+    int bPartial = sqlite3_column_int(pList, 4);
+    sqlite3_stmt *pXInfo = 0;
+    if( zIdx==0 ) break;
+    if( bPartial ){
+      memset(pIter->abIndexed, 0x01, sizeof(u8)*pIter->nTblCol);
+    }
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", zIdx)
+    );
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+      int iCid = sqlite3_column_int(pXInfo, 1);
+      if( iCid>=0 ) pIter->abIndexed[iCid] = 1;
+      if( iCid==-2 ){
+        memset(pIter->abIndexed, 0x01, sizeof(u8)*pIter->nTblCol);
+      }
+    }
+    rbuFinalize(p, pXInfo);
+    bIndex = 1;
+    pIter->nIndex++;
+  }
+
+  if( pIter->eType==RBU_PK_WITHOUT_ROWID ){
+    /* "PRAGMA index_list" includes the main PK b-tree */
+    pIter->nIndex--;
+  }
+
+  rbuFinalize(p, pList);
+  if( bIndex==0 ) pIter->abIndexed = 0;
+}
+
+
+/*
+** If they are not already populated, populate the pIter->azTblCol[],
+** pIter->abTblPk[], pIter->nTblCol and pIter->bRowid variables according to
+** the table (not index) that the iterator currently points to.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise. If
+** an error does occur, an error code and error message are also left in
+** the RBU handle.
+*/
+static int rbuObjIterCacheTableInfo(sqlite3rbu *p, RbuObjIter *pIter){
+  if( pIter->azTblCol==0 ){
+    sqlite3_stmt *pStmt = 0;
+    int nCol = 0;
+    int i;                        /* for() loop iterator variable */
+    int bRbuRowid = 0;            /* If input table has column "rbu_rowid" */
+    int iOrder = 0;
+    int iTnum = 0;
+
+    /* Figure out the type of table this step will deal with. */
+    assert( pIter->eType==0 );
+    rbuTableType(p, pIter->zTbl, &pIter->eType, &iTnum, &pIter->iPkTnum);
+    if( p->rc==SQLITE_OK && pIter->eType==RBU_PK_NOTABLE ){
+      p->rc = SQLITE_ERROR;
+      p->zErrmsg = sqlite3_mprintf("no such table: %s", pIter->zTbl);
+    }
+    if( p->rc ) return p->rc;
+    if( pIter->zIdx==0 ) pIter->iTnum = iTnum;
+
+    assert( pIter->eType==RBU_PK_NONE || pIter->eType==RBU_PK_IPK
+         || pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_WITHOUT_ROWID
+         || pIter->eType==RBU_PK_VTAB
+    );
+
+    /* Populate the azTblCol[] and nTblCol variables based on the columns
+    ** of the input table. Ignore any input table columns that begin with
+    ** "rbu_".  */
+    p->rc = prepareFreeAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
+        sqlite3_mprintf("SELECT * FROM '%q'", pIter->zDataTbl)
+    );
+    if( p->rc==SQLITE_OK ){
+      nCol = sqlite3_column_count(pStmt);
+      rbuAllocateIterArrays(p, pIter, nCol);
+    }
+    for(i=0; p->rc==SQLITE_OK && i<nCol; i++){
+      const char *zName = (const char*)sqlite3_column_name(pStmt, i);
+      if( sqlite3_strnicmp("rbu_", zName, 4) ){
+        char *zCopy = rbuStrndup(zName, &p->rc);
+        pIter->aiSrcOrder[pIter->nTblCol] = pIter->nTblCol;
+        pIter->azTblCol[pIter->nTblCol++] = zCopy;
+      }
+      else if( 0==sqlite3_stricmp("rbu_rowid", zName) ){
+        bRbuRowid = 1;
+      }
+    }
+    sqlite3_finalize(pStmt);
+    pStmt = 0;
+
+    if( p->rc==SQLITE_OK
+     && rbuIsVacuum(p)==0
+     && bRbuRowid!=(pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE)
+    ){
+      p->rc = SQLITE_ERROR;
+      p->zErrmsg = sqlite3_mprintf(
+          "table %q %s rbu_rowid column", pIter->zDataTbl,
+          (bRbuRowid ? "may not have" : "requires")
+      );
+    }
+
+    /* Check that all non-HIDDEN columns in the destination table are also
+    ** present in the input table. Populate the abTblPk[], azTblType[] and
+    ** aiTblOrder[] arrays at the same time.  */
+    if( p->rc==SQLITE_OK ){
+      p->rc = prepareFreeAndCollectError(p->dbMain, &pStmt, &p->zErrmsg,
+          sqlite3_mprintf("PRAGMA table_info(%Q)", pIter->zTbl)
+      );
+    }
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      const char *zName = (const char*)sqlite3_column_text(pStmt, 1);
+      if( zName==0 ) break;  /* An OOM - finalize() below returns S_NOMEM */
+      for(i=iOrder; i<pIter->nTblCol; i++){
+        if( 0==strcmp(zName, pIter->azTblCol[i]) ) break;
+      }
+      if( i==pIter->nTblCol ){
+        p->rc = SQLITE_ERROR;
+        p->zErrmsg = sqlite3_mprintf("column missing from %q: %s",
+            pIter->zDataTbl, zName
+        );
+      }else{
+        int iPk = sqlite3_column_int(pStmt, 5);
+        int bNotNull = sqlite3_column_int(pStmt, 3);
+        const char *zType = (const char*)sqlite3_column_text(pStmt, 2);
+
+        if( i!=iOrder ){
+          SWAP(int, pIter->aiSrcOrder[i], pIter->aiSrcOrder[iOrder]);
+          SWAP(char*, pIter->azTblCol[i], pIter->azTblCol[iOrder]);
+        }
+
+        pIter->azTblType[iOrder] = rbuStrndup(zType, &p->rc);
+        assert( iPk>=0 );
+        pIter->abTblPk[iOrder] = (u8)iPk;
+        pIter->abNotNull[iOrder] = (u8)bNotNull || (iPk!=0);
+        iOrder++;
+      }
+    }
+
+    rbuFinalize(p, pStmt);
+    rbuObjIterCacheIndexedCols(p, pIter);
+    assert( pIter->eType!=RBU_PK_VTAB || pIter->abIndexed==0 );
+    assert( pIter->eType!=RBU_PK_VTAB || pIter->nIndex==0 );
+  }
+
+  return p->rc;
+}
+
+/*
+** This function constructs and returns a pointer to a nul-terminated
+** string containing some SQL clause or list based on one or more of the
+** column names currently stored in the pIter->azTblCol[] array.
+*/
+static char *rbuObjIterGetCollist(
+  sqlite3rbu *p,                  /* RBU object */
+  RbuObjIter *pIter               /* Object iterator for column names */
+){
+  char *zList = 0;
+  const char *zSep = "";
+  int i;
+  for(i=0; i<pIter->nTblCol; i++){
+    const char *z = pIter->azTblCol[i];
+    zList = rbuMPrintf(p, "%z%s\"%w\"", zList, zSep, z);
+    zSep = ", ";
+  }
+  return zList;
+}
+
+/*
+** Return a comma separated list of the quoted PRIMARY KEY column names,
+** in order, for the current table. Before each column name, add the text
+** zPre. After each column name, add the zPost text. Use zSeparator as
+** the separator text (usually ", ").
+*/
+static char *rbuObjIterGetPkList(
+  sqlite3rbu *p,                  /* RBU object */
+  RbuObjIter *pIter,              /* Object iterator for column names */
+  const char *zPre,               /* Before each quoted column name */
+  const char *zSeparator,         /* Separator to use between columns */
+  const char *zPost               /* After each quoted column name */
+){
+  int iPk = 1;
+  char *zRet = 0;
+  const char *zSep = "";
+  while( 1 ){
+    int i;
+    for(i=0; i<pIter->nTblCol; i++){
+      if( (int)pIter->abTblPk[i]==iPk ){
+        const char *zCol = pIter->azTblCol[i];
+        zRet = rbuMPrintf(p, "%z%s%s\"%w\"%s", zRet, zSep, zPre, zCol, zPost);
+        zSep = zSeparator;
+        break;
+      }
+    }
+    if( i==pIter->nTblCol ) break;
+    iPk++;
+  }
+  return zRet;
+}
+
+/*
+** This function is called as part of restarting an RBU vacuum within
+** stage 1 of the process (while the *-oal file is being built) while
+** updating a table (not an index). The table may be a rowid table or
+** a WITHOUT ROWID table. It queries the target database to find the
+** largest key that has already been written to the target table and
+** constructs a WHERE clause that can be used to extract the remaining
+** rows from the source table. For a rowid table, the WHERE clause
+** is of the form:
+**
+**     "WHERE _rowid_ > ?"
+**
+** and for WITHOUT ROWID tables:
+**
+**     "WHERE (key1, key2) > (?, ?)"
+**
+** Instead of "?" placeholders, the actual WHERE clauses created by
+** this function contain literal SQL values.
+*/
+static char *rbuVacuumTableStart(
+  sqlite3rbu *p,                  /* RBU handle */
+  RbuObjIter *pIter,              /* RBU iterator object */
+  int bRowid,                     /* True for a rowid table */
+  const char *zWrite              /* Target table name prefix */
+){
+  sqlite3_stmt *pMax = 0;
+  char *zRet = 0;
+  if( bRowid ){
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pMax, &p->zErrmsg,
+        sqlite3_mprintf(
+          "SELECT max(_rowid_) FROM \"%s%w\"", zWrite, pIter->zTbl
+        )
+    );
+    if( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pMax) ){
+      sqlite3_int64 iMax = sqlite3_column_int64(pMax, 0);
+      zRet = rbuMPrintf(p, " WHERE _rowid_ > %lld ", iMax);
+    }
+    rbuFinalize(p, pMax);
+  }else{
+    char *zOrder = rbuObjIterGetPkList(p, pIter, "", ", ", " DESC");
+    char *zSelect = rbuObjIterGetPkList(p, pIter, "quote(", "||','||", ")");
+    char *zList = rbuObjIterGetPkList(p, pIter, "", ", ", "");
+
+    if( p->rc==SQLITE_OK ){
+      p->rc = prepareFreeAndCollectError(p->dbMain, &pMax, &p->zErrmsg,
+          sqlite3_mprintf(
+            "SELECT %s FROM \"%s%w\" ORDER BY %s LIMIT 1",
+                zSelect, zWrite, pIter->zTbl, zOrder
+          )
+      );
+      if( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pMax) ){
+        const char *zVal = (const char*)sqlite3_column_text(pMax, 0);
+        zRet = rbuMPrintf(p, " WHERE (%s) > (%s) ", zList, zVal);
+      }
+      rbuFinalize(p, pMax);
+    }
+
+    sqlite3_free(zOrder);
+    sqlite3_free(zSelect);
+    sqlite3_free(zList);
+  }
+  return zRet;
+}
+
+/*
+** This function is called as part of restating an RBU vacuum when the
+** current operation is writing content to an index. If possible, it
+** queries the target index b-tree for the largest key already written to
+** it, then composes and returns an expression that can be used in a WHERE
+** clause to select the remaining required rows from the source table.
+** It is only possible to return such an expression if:
+**
+**   * The index contains no DESC columns, and
+**   * The last key written to the index before the operation was
+**     suspended does not contain any NULL values.
+**
+** The expression is of the form:
+**
+**   (index-field1, index-field2, ...) > (?, ?, ...)
+**
+** except that the "?" placeholders are replaced with literal values.
+**
+** If the expression cannot be created, NULL is returned. In this case,
+** the caller has to use an OFFSET clause to extract only the required
+** rows from the sourct table, just as it does for an RBU update operation.
+*/
+static char *rbuVacuumIndexStart(
+  sqlite3rbu *p,                  /* RBU handle */
+  RbuObjIter *pIter               /* RBU iterator object */
+){
+  char *zOrder = 0;
+  char *zLhs = 0;
+  char *zSelect = 0;
+  char *zVector = 0;
+  char *zRet = 0;
+  int bFailed = 0;
+  const char *zSep = "";
+  int iCol = 0;
+  sqlite3_stmt *pXInfo = 0;
+
+  p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+      sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", pIter->zIdx)
+  );
+  while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+    int iCid = sqlite3_column_int(pXInfo, 1);
+    const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
+    const char *zCol;
+    if( sqlite3_column_int(pXInfo, 3) ){
+      bFailed = 1;
+      break;
+    }
+
+    if( iCid<0 ){
+      if( pIter->eType==RBU_PK_IPK ){
+        int i;
+        for(i=0; pIter->abTblPk[i]==0; i++);
+        assert( i<pIter->nTblCol );
+        zCol = pIter->azTblCol[i];
+      }else{
+        zCol = "_rowid_";
+      }
+    }else{
+      zCol = pIter->azTblCol[iCid];
+    }
+
+    zLhs = rbuMPrintf(p, "%z%s \"%w\" COLLATE %Q",
+        zLhs, zSep, zCol, zCollate
+        );
+    zOrder = rbuMPrintf(p, "%z%s \"rbu_imp_%d%w\" COLLATE %Q DESC",
+        zOrder, zSep, iCol, zCol, zCollate
+        );
+    zSelect = rbuMPrintf(p, "%z%s quote(\"rbu_imp_%d%w\")",
+        zSelect, zSep, iCol, zCol
+        );
+    zSep = ", ";
+    iCol++;
+  }
+  rbuFinalize(p, pXInfo);
+  if( bFailed ) goto index_start_out;
+
+  if( p->rc==SQLITE_OK ){
+    sqlite3_stmt *pSel = 0;
+
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pSel, &p->zErrmsg,
+        sqlite3_mprintf("SELECT %s FROM \"rbu_imp_%w\" ORDER BY %s LIMIT 1",
+          zSelect, pIter->zTbl, zOrder
+        )
+    );
+    if( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSel) ){
+      zSep = "";
+      for(iCol=0; iCol<pIter->nCol; iCol++){
+        const char *zQuoted = (const char*)sqlite3_column_text(pSel, iCol);
+        if( zQuoted==0 ){
+          p->rc = SQLITE_NOMEM;
+        }else if( zQuoted[0]=='N' ){
+          bFailed = 1;
+          break;
+        }
+        zVector = rbuMPrintf(p, "%z%s%s", zVector, zSep, zQuoted);
+        zSep = ", ";
+      }
+
+      if( !bFailed ){
+        zRet = rbuMPrintf(p, "(%s) > (%s)", zLhs, zVector);
+      }
+    }
+    rbuFinalize(p, pSel);
+  }
+
+ index_start_out:
+  sqlite3_free(zOrder);
+  sqlite3_free(zSelect);
+  sqlite3_free(zVector);
+  sqlite3_free(zLhs);
+  return zRet;
+}
+
+/*
+** This function is used to create a SELECT list (the list of SQL
+** expressions that follows a SELECT keyword) for a SELECT statement
+** used to read from an data_xxx or rbu_tmp_xxx table while updating the
+** index object currently indicated by the iterator object passed as the
+** second argument. A "PRAGMA index_xinfo = <idxname>" statement is used
+** to obtain the required information.
+**
+** If the index is of the following form:
+**
+**   CREATE INDEX i1 ON t1(c, b COLLATE nocase);
+**
+** and "t1" is a table with an explicit INTEGER PRIMARY KEY column
+** "ipk", the returned string is:
+**
+**   "`c` COLLATE 'BINARY', `b` COLLATE 'NOCASE', `ipk` COLLATE 'BINARY'"
+**
+** As well as the returned string, three other malloc'd strings are
+** returned via output parameters. As follows:
+**
+**   pzImposterCols: ...
+**   pzImposterPk: ...
+**   pzWhere: ...
+*/
+static char *rbuObjIterGetIndexCols(
+  sqlite3rbu *p,                  /* RBU object */
+  RbuObjIter *pIter,              /* Object iterator for column names */
+  char **pzImposterCols,          /* OUT: Columns for imposter table */
+  char **pzImposterPk,            /* OUT: Imposter PK clause */
+  char **pzWhere,                 /* OUT: WHERE clause */
+  int *pnBind                     /* OUT: Trbul number of columns */
+){
+  int rc = p->rc;                 /* Error code */
+  int rc2;                        /* sqlite3_finalize() return code */
+  char *zRet = 0;                 /* String to return */
+  char *zImpCols = 0;             /* String to return via *pzImposterCols */
+  char *zImpPK = 0;               /* String to return via *pzImposterPK */
+  char *zWhere = 0;               /* String to return via *pzWhere */
+  int nBind = 0;                  /* Value to return via *pnBind */
+  const char *zCom = "";          /* Set to ", " later on */
+  const char *zAnd = "";          /* Set to " AND " later on */
+  sqlite3_stmt *pXInfo = 0;       /* PRAGMA index_xinfo = ? */
+
+  if( rc==SQLITE_OK ){
+    assert( p->zErrmsg==0 );
+    rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", pIter->zIdx)
+    );
+  }
+
+  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+    int iCid = sqlite3_column_int(pXInfo, 1);
+    int bDesc = sqlite3_column_int(pXInfo, 3);
+    const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
+    const char *zCol = 0;
+    const char *zType;
+
+    if( iCid==-2 ){
+      int iSeq = sqlite3_column_int(pXInfo, 0);
+      zRet = sqlite3_mprintf("%z%s(%.*s) COLLATE %Q", zRet, zCom,
+          pIter->aIdxCol[iSeq].nSpan, pIter->aIdxCol[iSeq].zSpan, zCollate
+      );
+      zType = "";
+    }else {
+      if( iCid<0 ){
+        /* An integer primary key. If the table has an explicit IPK, use
+        ** its name. Otherwise, use "rbu_rowid".  */
+        if( pIter->eType==RBU_PK_IPK ){
+          int i;
+          for(i=0; pIter->abTblPk[i]==0; i++);
+          assert( i<pIter->nTblCol );
+          zCol = pIter->azTblCol[i];
+        }else if( rbuIsVacuum(p) ){
+          zCol = "_rowid_";
+        }else{
+          zCol = "rbu_rowid";
+        }
+        zType = "INTEGER";
+      }else{
+        zCol = pIter->azTblCol[iCid];
+        zType = pIter->azTblType[iCid];
+      }
+      zRet = sqlite3_mprintf("%z%s\"%w\" COLLATE %Q", zRet, zCom,zCol,zCollate);
+    }
+
+    if( pIter->bUnique==0 || sqlite3_column_int(pXInfo, 5) ){
+      const char *zOrder = (bDesc ? " DESC" : "");
+      zImpPK = sqlite3_mprintf("%z%s\"rbu_imp_%d%w\"%s",
+          zImpPK, zCom, nBind, zCol, zOrder
+      );
+    }
+    zImpCols = sqlite3_mprintf("%z%s\"rbu_imp_%d%w\" %s COLLATE %Q",
+        zImpCols, zCom, nBind, zCol, zType, zCollate
+    );
+    zWhere = sqlite3_mprintf(
+        "%z%s\"rbu_imp_%d%w\" IS ?", zWhere, zAnd, nBind, zCol
+    );
+    if( zRet==0 || zImpPK==0 || zImpCols==0 || zWhere==0 ) rc = SQLITE_NOMEM;
+    zCom = ", ";
+    zAnd = " AND ";
+    nBind++;
+  }
+
+  rc2 = sqlite3_finalize(pXInfo);
+  if( rc==SQLITE_OK ) rc = rc2;
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(zRet);
+    sqlite3_free(zImpCols);
+    sqlite3_free(zImpPK);
+    sqlite3_free(zWhere);
+    zRet = 0;
+    zImpCols = 0;
+    zImpPK = 0;
+    zWhere = 0;
+    p->rc = rc;
+  }
+
+  *pzImposterCols = zImpCols;
+  *pzImposterPk = zImpPK;
+  *pzWhere = zWhere;
+  *pnBind = nBind;
+  return zRet;
+}
+
+/*
+** Assuming the current table columns are "a", "b" and "c", and the zObj
+** paramter is passed "old", return a string of the form:
+**
+**     "old.a, old.b, old.b"
+**
+** With the column names escaped.
+**
+** For tables with implicit rowids - RBU_PK_EXTERNAL and RBU_PK_NONE, append
+** the text ", old._rowid_" to the returned value.
+*/
+static char *rbuObjIterGetOldlist(
+  sqlite3rbu *p,
+  RbuObjIter *pIter,
+  const char *zObj
+){
+  char *zList = 0;
+  if( p->rc==SQLITE_OK && pIter->abIndexed ){
+    const char *zS = "";
+    int i;
+    for(i=0; i<pIter->nTblCol; i++){
+      if( pIter->abIndexed[i] ){
+        const char *zCol = pIter->azTblCol[i];
+        zList = sqlite3_mprintf("%z%s%s.\"%w\"", zList, zS, zObj, zCol);
+      }else{
+        zList = sqlite3_mprintf("%z%sNULL", zList, zS);
+      }
+      zS = ", ";
+      if( zList==0 ){
+        p->rc = SQLITE_NOMEM;
+        break;
+      }
+    }
+
+    /* For a table with implicit rowids, append "old._rowid_" to the list. */
+    if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
+      zList = rbuMPrintf(p, "%z, %s._rowid_", zList, zObj);
+    }
+  }
+  return zList;
+}
+
+/*
+** Return an expression that can be used in a WHERE clause to match the
+** primary key of the current table. For example, if the table is:
+**
+**   CREATE TABLE t1(a, b, c, PRIMARY KEY(b, c));
+**
+** Return the string:
+**
+**   "b = ?1 AND c = ?2"
+*/
+static char *rbuObjIterGetWhere(
+  sqlite3rbu *p,
+  RbuObjIter *pIter
+){
+  char *zList = 0;
+  if( pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE ){
+    zList = rbuMPrintf(p, "_rowid_ = ?%d", pIter->nTblCol+1);
+  }else if( pIter->eType==RBU_PK_EXTERNAL ){
+    const char *zSep = "";
+    int i;
+    for(i=0; i<pIter->nTblCol; i++){
+      if( pIter->abTblPk[i] ){
+        zList = rbuMPrintf(p, "%z%sc%d=?%d", zList, zSep, i, i+1);
+        zSep = " AND ";
+      }
+    }
+    zList = rbuMPrintf(p,
+        "_rowid_ = (SELECT id FROM rbu_imposter2 WHERE %z)", zList
+    );
+
+  }else{
+    const char *zSep = "";
+    int i;
+    for(i=0; i<pIter->nTblCol; i++){
+      if( pIter->abTblPk[i] ){
+        const char *zCol = pIter->azTblCol[i];
+        zList = rbuMPrintf(p, "%z%s\"%w\"=?%d", zList, zSep, zCol, i+1);
+        zSep = " AND ";
+      }
+    }
+  }
+  return zList;
+}
+
+/*
+** The SELECT statement iterating through the keys for the current object
+** (p->objiter.pSelect) currently points to a valid row. However, there
+** is something wrong with the rbu_control value in the rbu_control value
+** stored in the (p->nCol+1)'th column. Set the error code and error message
+** of the RBU handle to something reflecting this.
+*/
+static void rbuBadControlError(sqlite3rbu *p){
+  p->rc = SQLITE_ERROR;
+  p->zErrmsg = sqlite3_mprintf("invalid rbu_control value");
+}
+
+
+/*
+** Return a nul-terminated string containing the comma separated list of
+** assignments that should be included following the "SET" keyword of
+** an UPDATE statement used to update the table object that the iterator
+** passed as the second argument currently points to if the rbu_control
+** column of the data_xxx table entry is set to zMask.
+**
+** The memory for the returned string is obtained from sqlite3_malloc().
+** It is the responsibility of the caller to eventually free it using
+** sqlite3_free().
+**
+** If an OOM error is encountered when allocating space for the new
+** string, an error code is left in the rbu handle passed as the first
+** argument and NULL is returned. Or, if an error has already occurred
+** when this function is called, NULL is returned immediately, without
+** attempting the allocation or modifying the stored error code.
+*/
+static char *rbuObjIterGetSetlist(
+  sqlite3rbu *p,
+  RbuObjIter *pIter,
+  const char *zMask
+){
+  char *zList = 0;
+  if( p->rc==SQLITE_OK ){
+    int i;
+
+    if( (int)strlen(zMask)!=pIter->nTblCol ){
+      rbuBadControlError(p);
+    }else{
+      const char *zSep = "";
+      for(i=0; i<pIter->nTblCol; i++){
+        char c = zMask[pIter->aiSrcOrder[i]];
+        if( c=='x' ){
+          zList = rbuMPrintf(p, "%z%s\"%w\"=?%d",
+              zList, zSep, pIter->azTblCol[i], i+1
+          );
+          zSep = ", ";
+        }
+        else if( c=='d' ){
+          zList = rbuMPrintf(p, "%z%s\"%w\"=rbu_delta(\"%w\", ?%d)",
+              zList, zSep, pIter->azTblCol[i], pIter->azTblCol[i], i+1
+          );
+          zSep = ", ";
+        }
+        else if( c=='f' ){
+          zList = rbuMPrintf(p, "%z%s\"%w\"=rbu_fossil_delta(\"%w\", ?%d)",
+              zList, zSep, pIter->azTblCol[i], pIter->azTblCol[i], i+1
+          );
+          zSep = ", ";
+        }
+      }
+    }
+  }
+  return zList;
+}
+
+/*
+** Return a nul-terminated string consisting of nByte comma separated
+** "?" expressions. For example, if nByte is 3, return a pointer to
+** a buffer containing the string "?,?,?".
+**
+** The memory for the returned string is obtained from sqlite3_malloc().
+** It is the responsibility of the caller to eventually free it using
+** sqlite3_free().
+**
+** If an OOM error is encountered when allocating space for the new
+** string, an error code is left in the rbu handle passed as the first
+** argument and NULL is returned. Or, if an error has already occurred
+** when this function is called, NULL is returned immediately, without
+** attempting the allocation or modifying the stored error code.
+*/
+static char *rbuObjIterGetBindlist(sqlite3rbu *p, int nBind){
+  char *zRet = 0;
+  sqlite3_int64 nByte = 2*(sqlite3_int64)nBind + 1;
+
+  zRet = (char*)rbuMalloc(p, nByte);
+  if( zRet ){
+    int i;
+    for(i=0; i<nBind; i++){
+      zRet[i*2] = '?';
+      zRet[i*2+1] = (i+1==nBind) ? '\0' : ',';
+    }
+  }
+  return zRet;
+}
+
+/*
+** The iterator currently points to a table (not index) of type
+** RBU_PK_WITHOUT_ROWID. This function creates the PRIMARY KEY
+** declaration for the corresponding imposter table. For example,
+** if the iterator points to a table created as:
+**
+**   CREATE TABLE t1(a, b, c, PRIMARY KEY(b, a DESC)) WITHOUT ROWID
+**
+** this function returns:
+**
+**   PRIMARY KEY("b", "a" DESC)
+*/
+static char *rbuWithoutRowidPK(sqlite3rbu *p, RbuObjIter *pIter){
+  char *z = 0;
+  assert( pIter->zIdx==0 );
+  if( p->rc==SQLITE_OK ){
+    const char *zSep = "PRIMARY KEY(";
+    sqlite3_stmt *pXList = 0;     /* PRAGMA index_list = (pIter->zTbl) */
+    sqlite3_stmt *pXInfo = 0;     /* PRAGMA index_xinfo = <pk-index> */
+
+    p->rc = prepareFreeAndCollectError(p->dbMain, &pXList, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.index_list = %Q", pIter->zTbl)
+    );
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXList) ){
+      const char *zOrig = (const char*)sqlite3_column_text(pXList,3);
+      if( zOrig && strcmp(zOrig, "pk")==0 ){
+        const char *zIdx = (const char*)sqlite3_column_text(pXList,1);
+        if( zIdx ){
+          p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+              sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", zIdx)
+          );
+        }
+        break;
+      }
+    }
+    rbuFinalize(p, pXList);
+
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+      if( sqlite3_column_int(pXInfo, 5) ){
+        /* int iCid = sqlite3_column_int(pXInfo, 0); */
+        const char *zCol = (const char*)sqlite3_column_text(pXInfo, 2);
+        const char *zDesc = sqlite3_column_int(pXInfo, 3) ? " DESC" : "";
+        z = rbuMPrintf(p, "%z%s\"%w\"%s", z, zSep, zCol, zDesc);
+        zSep = ", ";
+      }
+    }
+    z = rbuMPrintf(p, "%z)", z);
+    rbuFinalize(p, pXInfo);
+  }
+  return z;
+}
+
+/*
+** This function creates the second imposter table used when writing to
+** a table b-tree where the table has an external primary key. If the
+** iterator passed as the second argument does not currently point to
+** a table (not index) with an external primary key, this function is a
+** no-op.
+**
+** Assuming the iterator does point to a table with an external PK, this
+** function creates a WITHOUT ROWID imposter table named "rbu_imposter2"
+** used to access that PK index. For example, if the target table is
+** declared as follows:
+**
+**   CREATE TABLE t1(a, b TEXT, c REAL, PRIMARY KEY(b, c));
+**
+** then the imposter table schema is:
+**
+**   CREATE TABLE rbu_imposter2(c1 TEXT, c2 REAL, id INTEGER) WITHOUT ROWID;
+**
+*/
+static void rbuCreateImposterTable2(sqlite3rbu *p, RbuObjIter *pIter){
+  if( p->rc==SQLITE_OK && pIter->eType==RBU_PK_EXTERNAL ){
+    int tnum = pIter->iPkTnum;    /* Root page of PK index */
+    sqlite3_stmt *pQuery = 0;     /* SELECT name ... WHERE rootpage = $tnum */
+    const char *zIdx = 0;         /* Name of PK index */
+    sqlite3_stmt *pXInfo = 0;     /* PRAGMA main.index_xinfo = $zIdx */
+    const char *zComma = "";
+    char *zCols = 0;              /* Used to build up list of table cols */
+    char *zPk = 0;                /* Used to build up table PK declaration */
+
+    /* Figure out the name of the primary key index for the current table.
+    ** This is needed for the argument to "PRAGMA index_xinfo". Set
+    ** zIdx to point to a nul-terminated string containing this name. */
+    p->rc = prepareAndCollectError(p->dbMain, &pQuery, &p->zErrmsg,
+        "SELECT name FROM sqlite_schema WHERE rootpage = ?"
+    );
+    if( p->rc==SQLITE_OK ){
+      sqlite3_bind_int(pQuery, 1, tnum);
+      if( SQLITE_ROW==sqlite3_step(pQuery) ){
+        zIdx = (const char*)sqlite3_column_text(pQuery, 0);
+      }
+    }
+    if( zIdx ){
+      p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
+          sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", zIdx)
+      );
+    }
+    rbuFinalize(p, pQuery);
+
+    while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
+      int bKey = sqlite3_column_int(pXInfo, 5);
+      if( bKey ){
+        int iCid = sqlite3_column_int(pXInfo, 1);
+        int bDesc = sqlite3_column_int(pXInfo, 3);
+        const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
+        zCols = rbuMPrintf(p, "%z%sc%d %s COLLATE %Q", zCols, zComma,
+            iCid, pIter->azTblType[iCid], zCollate
+        );
+        zPk = rbuMPrintf(p, "%z%sc%d%s", zPk, zComma, iCid, bDesc?" DESC":"");
+        zComma = ", ";
+      }
+    }
+    zCols = rbuMPrintf(p, "%z, id INTEGER", zCols);
+    rbuFinalize(p, pXInfo);
+
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 1, tnum);
+    rbuMPrintfExec(p, p->dbMain,
+        "CREATE TABLE rbu_imposter2(%z, PRIMARY KEY(%z)) WITHOUT ROWID",
+        zCols, zPk
+    );
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 0);
+  }
+}
+
+/*
+** If an error has already occurred when this function is called, it
+** immediately returns zero (without doing any work). Or, if an error
+** occurs during the execution of this function, it sets the error code
+** in the sqlite3rbu object indicated by the first argument and returns
+** zero.
+**
+** The iterator passed as the second argument is guaranteed to point to
+** a table (not an index) when this function is called. This function
+** attempts to create any imposter table required to write to the main
+** table b-tree of the table before returning. Non-zero is returned if
+** an imposter table are created, or zero otherwise.
+**
+** An imposter table is required in all cases except RBU_PK_VTAB. Only
+** virtual tables are written to directly. The imposter table has the
+** same schema as the actual target table (less any UNIQUE constraints).
+** More precisely, the "same schema" means the same columns, types,
+** collation sequences. For tables that do not have an external PRIMARY
+** KEY, it also means the same PRIMARY KEY declaration.
+*/
+static void rbuCreateImposterTable(sqlite3rbu *p, RbuObjIter *pIter){
+  if( p->rc==SQLITE_OK && pIter->eType!=RBU_PK_VTAB ){
+    int tnum = pIter->iTnum;
+    const char *zComma = "";
+    char *zSql = 0;
+    int iCol;
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 1);
+
+    for(iCol=0; p->rc==SQLITE_OK && iCol<pIter->nTblCol; iCol++){
+      const char *zPk = "";
+      const char *zCol = pIter->azTblCol[iCol];
+      const char *zColl = 0;
+
+      p->rc = sqlite3_table_column_metadata(
+          p->dbMain, "main", pIter->zTbl, zCol, 0, &zColl, 0, 0, 0
+      );
+
+      if( pIter->eType==RBU_PK_IPK && pIter->abTblPk[iCol] ){
+        /* If the target table column is an "INTEGER PRIMARY KEY", add
+        ** "PRIMARY KEY" to the imposter table column declaration. */
+        zPk = "PRIMARY KEY ";
+      }
+      zSql = rbuMPrintf(p, "%z%s\"%w\" %s %sCOLLATE %Q%s",
+          zSql, zComma, zCol, pIter->azTblType[iCol], zPk, zColl,
+          (pIter->abNotNull[iCol] ? " NOT NULL" : "")
+      );
+      zComma = ", ";
+    }
+
+    if( pIter->eType==RBU_PK_WITHOUT_ROWID ){
+      char *zPk = rbuWithoutRowidPK(p, pIter);
+      if( zPk ){
+        zSql = rbuMPrintf(p, "%z, %z", zSql, zPk);
+      }
+    }
+
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 1, tnum);
+    rbuMPrintfExec(p, p->dbMain, "CREATE TABLE \"rbu_imp_%w\"(%z)%s",
+        pIter->zTbl, zSql,
+        (pIter->eType==RBU_PK_WITHOUT_ROWID ? " WITHOUT ROWID" : "")
+    );
+    sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 0);
+  }
+}
+
+/*
+** Prepare a statement used to insert rows into the "rbu_tmp_xxx" table.
+** Specifically a statement of the form:
+**
+**     INSERT INTO rbu_tmp_xxx VALUES(?, ?, ? ...);
+**
+** The number of bound variables is equal to the number of columns in
+** the target table, plus one (for the rbu_control column), plus one more
+** (for the rbu_rowid column) if the target table is an implicit IPK or
+** virtual table.
+*/
+static void rbuObjIterPrepareTmpInsert(
+  sqlite3rbu *p,
+  RbuObjIter *pIter,
+  const char *zCollist,
+  const char *zRbuRowid
+){
+  int bRbuRowid = (pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE);
+  char *zBind = rbuObjIterGetBindlist(p, pIter->nTblCol + 1 + bRbuRowid);
+  if( zBind ){
+    assert( pIter->pTmpInsert==0 );
+    p->rc = prepareFreeAndCollectError(
+        p->dbRbu, &pIter->pTmpInsert, &p->zErrmsg, sqlite3_mprintf(
+          "INSERT INTO %s.'rbu_tmp_%q'(rbu_control,%s%s) VALUES(%z)",
+          p->zStateDb, pIter->zDataTbl, zCollist, zRbuRowid, zBind
+    ));
+  }
+}
+
+static void rbuTmpInsertFunc(
+  sqlite3_context *pCtx,
+  int nVal,
+  sqlite3_value **apVal
+){
+  sqlite3rbu *p = sqlite3_user_data(pCtx);
+  int rc = SQLITE_OK;
+  int i;
+
+  assert( sqlite3_value_int(apVal[0])!=0
+      || p->objiter.eType==RBU_PK_EXTERNAL
+      || p->objiter.eType==RBU_PK_NONE
+  );
+  if( sqlite3_value_int(apVal[0])!=0 ){
+    p->nPhaseOneStep += p->objiter.nIndex;
+  }
+
+  for(i=0; rc==SQLITE_OK && i<nVal; i++){
+    rc = sqlite3_bind_value(p->objiter.pTmpInsert, i+1, apVal[i]);
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3_step(p->objiter.pTmpInsert);
+    rc = sqlite3_reset(p->objiter.pTmpInsert);
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+  }
+}
+
+static char *rbuObjIterGetIndexWhere(sqlite3rbu *p, RbuObjIter *pIter){
+  sqlite3_stmt *pStmt = 0;
+  int rc = p->rc;
+  char *zRet = 0;
+
+  assert( pIter->zIdxSql==0 && pIter->nIdxCol==0 && pIter->aIdxCol==0 );
+
+  if( rc==SQLITE_OK ){
+    rc = prepareAndCollectError(p->dbMain, &pStmt, &p->zErrmsg,
+        "SELECT trim(sql) FROM sqlite_schema WHERE type='index' AND name=?"
+    );
+  }
+  if( rc==SQLITE_OK ){
+    int rc2;
+    rc = sqlite3_bind_text(pStmt, 1, pIter->zIdx, -1, SQLITE_STATIC);
+    if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+      char *zSql = (char*)sqlite3_column_text(pStmt, 0);
+      if( zSql ){
+        pIter->zIdxSql = zSql = rbuStrndup(zSql, &rc);
+      }
+      if( zSql ){
+        int nParen = 0;           /* Number of open parenthesis */
+        int i;
+        int iIdxCol = 0;
+        int nIdxAlloc = 0;
+        for(i=0; zSql[i]; i++){
+          char c = zSql[i];
+
+          /* If necessary, grow the pIter->aIdxCol[] array */
+          if( iIdxCol==nIdxAlloc ){
+            RbuSpan *aIdxCol = (RbuSpan*)sqlite3_realloc(
+                pIter->aIdxCol, (nIdxAlloc+16)*sizeof(RbuSpan)
+            );
+            if( aIdxCol==0 ){
+              rc = SQLITE_NOMEM;
+              break;
+            }
+            pIter->aIdxCol = aIdxCol;
+            nIdxAlloc += 16;
+          }
+
+          if( c=='(' ){
+            if( nParen==0 ){
+              assert( iIdxCol==0 );
+              pIter->aIdxCol[0].zSpan = &zSql[i+1];
+            }
+            nParen++;
+          }
+          else if( c==')' ){
+            nParen--;
+            if( nParen==0 ){
+              int nSpan = (int)(&zSql[i] - pIter->aIdxCol[iIdxCol].zSpan);
+              pIter->aIdxCol[iIdxCol++].nSpan = nSpan;
+              i++;
+              break;
+            }
+          }else if( c==',' && nParen==1 ){
+            int nSpan = (int)(&zSql[i] - pIter->aIdxCol[iIdxCol].zSpan);
+            pIter->aIdxCol[iIdxCol++].nSpan = nSpan;
+            pIter->aIdxCol[iIdxCol].zSpan = &zSql[i+1];
+          }else if( c=='"' || c=='\'' || c=='`' ){
+            for(i++; 1; i++){
+              if( zSql[i]==c ){
+                if( zSql[i+1]!=c ) break;
+                i++;
+              }
+            }
+          }else if( c=='[' ){
+            for(i++; 1; i++){
+              if( zSql[i]==']' ) break;
+            }
+          }else if( c=='-' && zSql[i+1]=='-' ){
+            for(i=i+2; zSql[i] && zSql[i]!='\n'; i++);
+            if( zSql[i]=='\0' ) break;
+          }else if( c=='/' && zSql[i+1]=='*' ){
+            for(i=i+2; zSql[i] && (zSql[i]!='*' || zSql[i+1]!='/'); i++);
+            if( zSql[i]=='\0' ) break;
+            i++;
+          }
+        }
+        if( zSql[i] ){
+          zRet = rbuStrndup(&zSql[i], &rc);
+        }
+        pIter->nIdxCol = iIdxCol;
+      }
+    }
+
+    rc2 = sqlite3_finalize(pStmt);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  p->rc = rc;
+  return zRet;
+}
+
+/*
+** Ensure that the SQLite statement handles required to update the
+** target database object currently indicated by the iterator passed
+** as the second argument are available.
+*/
+static int rbuObjIterPrepareAll(
+  sqlite3rbu *p,
+  RbuObjIter *pIter,
+  int nOffset                     /* Add "LIMIT -1 OFFSET $nOffset" to SELECT */
+){
+  assert( pIter->bCleanup==0 );
+  if( pIter->pSelect==0 && rbuObjIterCacheTableInfo(p, pIter)==SQLITE_OK ){
+    const int tnum = pIter->iTnum;
+    char *zCollist = 0;           /* List of indexed columns */
+    char **pz = &p->zErrmsg;
+    const char *zIdx = pIter->zIdx;
+    char *zLimit = 0;
+
+    if( nOffset ){
+      zLimit = sqlite3_mprintf(" LIMIT -1 OFFSET %d", nOffset);
+      if( !zLimit ) p->rc = SQLITE_NOMEM;
+    }
+
+    if( zIdx ){
+      const char *zTbl = pIter->zTbl;
+      char *zImposterCols = 0;    /* Columns for imposter table */
+      char *zImposterPK = 0;      /* Primary key declaration for imposter */
+      char *zWhere = 0;           /* WHERE clause on PK columns */
+      char *zBind = 0;
+      char *zPart = 0;
+      int nBind = 0;
+
+      assert( pIter->eType!=RBU_PK_VTAB );
+      zPart = rbuObjIterGetIndexWhere(p, pIter);
+      zCollist = rbuObjIterGetIndexCols(
+          p, pIter, &zImposterCols, &zImposterPK, &zWhere, &nBind
+      );
+      zBind = rbuObjIterGetBindlist(p, nBind);
+
+      /* Create the imposter table used to write to this index. */
+      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 1);
+      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 1,tnum);
+      rbuMPrintfExec(p, p->dbMain,
+          "CREATE TABLE \"rbu_imp_%w\"( %s, PRIMARY KEY( %s ) ) WITHOUT ROWID",
+          zTbl, zImposterCols, zImposterPK
+      );
+      sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 0);
+
+      /* Create the statement to insert index entries */
+      pIter->nCol = nBind;
+      if( p->rc==SQLITE_OK ){
+        p->rc = prepareFreeAndCollectError(
+            p->dbMain, &pIter->pInsert, &p->zErrmsg,
+          sqlite3_mprintf("INSERT INTO \"rbu_imp_%w\" VALUES(%s)", zTbl, zBind)
+        );
+      }
+
+      /* And to delete index entries */
+      if( rbuIsVacuum(p)==0 && p->rc==SQLITE_OK ){
+        p->rc = prepareFreeAndCollectError(
+            p->dbMain, &pIter->pDelete, &p->zErrmsg,
+          sqlite3_mprintf("DELETE FROM \"rbu_imp_%w\" WHERE %s", zTbl, zWhere)
+        );
+      }
+
+      /* Create the SELECT statement to read keys in sorted order */
+      if( p->rc==SQLITE_OK ){
+        char *zSql;
+        if( rbuIsVacuum(p) ){
+          char *zStart = 0;
+          if( nOffset ){
+            zStart = rbuVacuumIndexStart(p, pIter);
+            if( zStart ){
+              sqlite3_free(zLimit);
+              zLimit = 0;
+            }
+          }
+
+          zSql = sqlite3_mprintf(
+              "SELECT %s, 0 AS rbu_control FROM '%q' %s %s %s ORDER BY %s%s",
+              zCollist,
+              pIter->zDataTbl,
+              zPart,
+              (zStart ? (zPart ? "AND" : "WHERE") : ""), zStart,
+              zCollist, zLimit
+          );
+          sqlite3_free(zStart);
+        }else
+
+        if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
+          zSql = sqlite3_mprintf(
+              "SELECT %s, rbu_control FROM %s.'rbu_tmp_%q' %s ORDER BY %s%s",
+              zCollist, p->zStateDb, pIter->zDataTbl,
+              zPart, zCollist, zLimit
+          );
+        }else{
+          zSql = sqlite3_mprintf(
+              "SELECT %s, rbu_control FROM %s.'rbu_tmp_%q' %s "
+              "UNION ALL "
+              "SELECT %s, rbu_control FROM '%q' "
+              "%s %s typeof(rbu_control)='integer' AND rbu_control!=1 "
+              "ORDER BY %s%s",
+              zCollist, p->zStateDb, pIter->zDataTbl, zPart,
+              zCollist, pIter->zDataTbl,
+              zPart,
+              (zPart ? "AND" : "WHERE"),
+              zCollist, zLimit
+          );
+        }
+        if( p->rc==SQLITE_OK ){
+          p->rc = prepareFreeAndCollectError(p->dbRbu,&pIter->pSelect,pz,zSql);
+        }else{
+          sqlite3_free(zSql);
+        }
+      }
+
+      sqlite3_free(zImposterCols);
+      sqlite3_free(zImposterPK);
+      sqlite3_free(zWhere);
+      sqlite3_free(zBind);
+      sqlite3_free(zPart);
+    }else{
+      int bRbuRowid = (pIter->eType==RBU_PK_VTAB)
+                    ||(pIter->eType==RBU_PK_NONE)
+                    ||(pIter->eType==RBU_PK_EXTERNAL && rbuIsVacuum(p));
+      const char *zTbl = pIter->zTbl;       /* Table this step applies to */
+      const char *zWrite;                   /* Imposter table name */
+
+      char *zBindings = rbuObjIterGetBindlist(p, pIter->nTblCol + bRbuRowid);
+      char *zWhere = rbuObjIterGetWhere(p, pIter);
+      char *zOldlist = rbuObjIterGetOldlist(p, pIter, "old");
+      char *zNewlist = rbuObjIterGetOldlist(p, pIter, "new");
+
+      zCollist = rbuObjIterGetCollist(p, pIter);
+      pIter->nCol = pIter->nTblCol;
+
+      /* Create the imposter table or tables (if required). */
+      rbuCreateImposterTable(p, pIter);
+      rbuCreateImposterTable2(p, pIter);
+      zWrite = (pIter->eType==RBU_PK_VTAB ? "" : "rbu_imp_");
+
+      /* Create the INSERT statement to write to the target PK b-tree */
+      if( p->rc==SQLITE_OK ){
+        p->rc = prepareFreeAndCollectError(p->dbMain, &pIter->pInsert, pz,
+            sqlite3_mprintf(
+              "INSERT INTO \"%s%w\"(%s%s) VALUES(%s)",
+              zWrite, zTbl, zCollist, (bRbuRowid ? ", _rowid_" : ""), zBindings
+            )
+        );
+      }
+
+      /* Create the DELETE statement to write to the target PK b-tree.
+      ** Because it only performs INSERT operations, this is not required for
+      ** an rbu vacuum handle.  */
+      if( rbuIsVacuum(p)==0 && p->rc==SQLITE_OK ){
+        p->rc = prepareFreeAndCollectError(p->dbMain, &pIter->pDelete, pz,
+            sqlite3_mprintf(
+              "DELETE FROM \"%s%w\" WHERE %s", zWrite, zTbl, zWhere
+            )
+        );
+      }
+
+      if( rbuIsVacuum(p)==0 && pIter->abIndexed ){
+        const char *zRbuRowid = "";
+        if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
+          zRbuRowid = ", rbu_rowid";
+        }
+
+        /* Create the rbu_tmp_xxx table and the triggers to populate it. */
+        rbuMPrintfExec(p, p->dbRbu,
+            "CREATE TABLE IF NOT EXISTS %s.'rbu_tmp_%q' AS "
+            "SELECT *%s FROM '%q' WHERE 0;"
+            , p->zStateDb, pIter->zDataTbl
+            , (pIter->eType==RBU_PK_EXTERNAL ? ", 0 AS rbu_rowid" : "")
+            , pIter->zDataTbl
+        );
+
+        rbuMPrintfExec(p, p->dbMain,
+            "CREATE TEMP TRIGGER rbu_delete_tr BEFORE DELETE ON \"%s%w\" "
+            "BEGIN "
+            "  SELECT rbu_tmp_insert(3, %s);"
+            "END;"
+
+            "CREATE TEMP TRIGGER rbu_update1_tr BEFORE UPDATE ON \"%s%w\" "
+            "BEGIN "
+            "  SELECT rbu_tmp_insert(3, %s);"
+            "END;"
+
+            "CREATE TEMP TRIGGER rbu_update2_tr AFTER UPDATE ON \"%s%w\" "
+            "BEGIN "
+            "  SELECT rbu_tmp_insert(4, %s);"
+            "END;",
+            zWrite, zTbl, zOldlist,
+            zWrite, zTbl, zOldlist,
+            zWrite, zTbl, zNewlist
+        );
+
+        if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
+          rbuMPrintfExec(p, p->dbMain,
+              "CREATE TEMP TRIGGER rbu_insert_tr AFTER INSERT ON \"%s%w\" "
+              "BEGIN "
+              "  SELECT rbu_tmp_insert(0, %s);"
+              "END;",
+              zWrite, zTbl, zNewlist
+          );
+        }
+
+        rbuObjIterPrepareTmpInsert(p, pIter, zCollist, zRbuRowid);
+      }
+
+      /* Create the SELECT statement to read keys from data_xxx */
+      if( p->rc==SQLITE_OK ){
+        const char *zRbuRowid = "";
+        char *zStart = 0;
+        char *zOrder = 0;
+        if( bRbuRowid ){
+          zRbuRowid = rbuIsVacuum(p) ? ",_rowid_ " : ",rbu_rowid";
+        }
+
+        if( rbuIsVacuum(p) ){
+          if( nOffset ){
+            zStart = rbuVacuumTableStart(p, pIter, bRbuRowid, zWrite);
+            if( zStart ){
+              sqlite3_free(zLimit);
+              zLimit = 0;
+            }
+          }
+          if( bRbuRowid ){
+            zOrder = rbuMPrintf(p, "_rowid_");
+          }else{
+            zOrder = rbuObjIterGetPkList(p, pIter, "", ", ", "");
+          }
+        }
+
+        if( p->rc==SQLITE_OK ){
+          p->rc = prepareFreeAndCollectError(p->dbRbu, &pIter->pSelect, pz,
+              sqlite3_mprintf(
+                "SELECT %s,%s rbu_control%s FROM '%q'%s %s %s %s",
+                zCollist,
+                (rbuIsVacuum(p) ? "0 AS " : ""),
+                zRbuRowid,
+                pIter->zDataTbl, (zStart ? zStart : ""),
+                (zOrder ? "ORDER BY" : ""), zOrder,
+                zLimit
+              )
+          );
+        }
+        sqlite3_free(zStart);
+        sqlite3_free(zOrder);
+      }
+
+      sqlite3_free(zWhere);
+      sqlite3_free(zOldlist);
+      sqlite3_free(zNewlist);
+      sqlite3_free(zBindings);
+    }
+    sqlite3_free(zCollist);
+    sqlite3_free(zLimit);
+  }
+
+  return p->rc;
+}
+
+/*
+** Set output variable *ppStmt to point to an UPDATE statement that may
+** be used to update the imposter table for the main table b-tree of the
+** table object that pIter currently points to, assuming that the
+** rbu_control column of the data_xyz table contains zMask.
+**
+** If the zMask string does not specify any columns to update, then this
+** is not an error. Output variable *ppStmt is set to NULL in this case.
+*/
+static int rbuGetUpdateStmt(
+  sqlite3rbu *p,                  /* RBU handle */
+  RbuObjIter *pIter,              /* Object iterator */
+  const char *zMask,              /* rbu_control value ('x.x.') */
+  sqlite3_stmt **ppStmt           /* OUT: UPDATE statement handle */
+){
+  RbuUpdateStmt **pp;
+  RbuUpdateStmt *pUp = 0;
+  int nUp = 0;
+
+  /* In case an error occurs */
+  *ppStmt = 0;
+
+  /* Search for an existing statement. If one is found, shift it to the front
+  ** of the LRU queue and return immediately. Otherwise, leave nUp pointing
+  ** to the number of statements currently in the cache and pUp to the
+  ** last object in the list.  */
+  for(pp=&pIter->pRbuUpdate; *pp; pp=&((*pp)->pNext)){
+    pUp = *pp;
+    if( strcmp(pUp->zMask, zMask)==0 ){
+      *pp = pUp->pNext;
+      pUp->pNext = pIter->pRbuUpdate;
+      pIter->pRbuUpdate = pUp;
+      *ppStmt = pUp->pUpdate;
+      return SQLITE_OK;
+    }
+    nUp++;
+  }
+  assert( pUp==0 || pUp->pNext==0 );
+
+  if( nUp>=SQLITE_RBU_UPDATE_CACHESIZE ){
+    for(pp=&pIter->pRbuUpdate; *pp!=pUp; pp=&((*pp)->pNext));
+    *pp = 0;
+    sqlite3_finalize(pUp->pUpdate);
+    pUp->pUpdate = 0;
+  }else{
+    pUp = (RbuUpdateStmt*)rbuMalloc(p, sizeof(RbuUpdateStmt)+pIter->nTblCol+1);
+  }
+
+  if( pUp ){
+    char *zWhere = rbuObjIterGetWhere(p, pIter);
+    char *zSet = rbuObjIterGetSetlist(p, pIter, zMask);
+    char *zUpdate = 0;
+
+    pUp->zMask = (char*)&pUp[1];
+    memcpy(pUp->zMask, zMask, pIter->nTblCol);
+    pUp->pNext = pIter->pRbuUpdate;
+    pIter->pRbuUpdate = pUp;
+
+    if( zSet ){
+      const char *zPrefix = "";
+
+      if( pIter->eType!=RBU_PK_VTAB ) zPrefix = "rbu_imp_";
+      zUpdate = sqlite3_mprintf("UPDATE \"%s%w\" SET %s WHERE %s",
+          zPrefix, pIter->zTbl, zSet, zWhere
+      );
+      p->rc = prepareFreeAndCollectError(
+          p->dbMain, &pUp->pUpdate, &p->zErrmsg, zUpdate
+      );
+      *ppStmt = pUp->pUpdate;
+    }
+    sqlite3_free(zWhere);
+    sqlite3_free(zSet);
+  }
+
+  return p->rc;
+}
+
+static sqlite3 *rbuOpenDbhandle(
+  sqlite3rbu *p,
+  const char *zName,
+  int bUseVfs
+){
+  sqlite3 *db = 0;
+  if( p->rc==SQLITE_OK ){
+    const int flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_URI;
+    p->rc = sqlite3_open_v2(zName, &db, flags, bUseVfs ? p->zVfsName : 0);
+    if( p->rc ){
+      p->zErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+      sqlite3_close(db);
+      db = 0;
+    }
+  }
+  return db;
+}
+
+/*
+** Free an RbuState object allocated by rbuLoadState().
+*/
+static void rbuFreeState(RbuState *p){
+  if( p ){
+    sqlite3_free(p->zTbl);
+    sqlite3_free(p->zDataTbl);
+    sqlite3_free(p->zIdx);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Allocate an RbuState object and load the contents of the rbu_state
+** table into it. Return a pointer to the new object. It is the
+** responsibility of the caller to eventually free the object using
+** sqlite3_free().
+**
+** If an error occurs, leave an error code and message in the rbu handle
+** and return NULL.
+*/
+static RbuState *rbuLoadState(sqlite3rbu *p){
+  RbuState *pRet = 0;
+  sqlite3_stmt *pStmt = 0;
+  int rc;
+  int rc2;
+
+  pRet = (RbuState*)rbuMalloc(p, sizeof(RbuState));
+  if( pRet==0 ) return 0;
+
+  rc = prepareFreeAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
+      sqlite3_mprintf("SELECT k, v FROM %s.rbu_state", p->zStateDb)
+  );
+  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+    switch( sqlite3_column_int(pStmt, 0) ){
+      case RBU_STATE_STAGE:
+        pRet->eStage = sqlite3_column_int(pStmt, 1);
+        if( pRet->eStage!=RBU_STAGE_OAL
+         && pRet->eStage!=RBU_STAGE_MOVE
+         && pRet->eStage!=RBU_STAGE_CKPT
+        ){
+          p->rc = SQLITE_CORRUPT;
+        }
+        break;
+
+      case RBU_STATE_TBL:
+        pRet->zTbl = rbuStrndup((char*)sqlite3_column_text(pStmt, 1), &rc);
+        break;
+
+      case RBU_STATE_IDX:
+        pRet->zIdx = rbuStrndup((char*)sqlite3_column_text(pStmt, 1), &rc);
+        break;
+
+      case RBU_STATE_ROW:
+        pRet->nRow = sqlite3_column_int(pStmt, 1);
+        break;
+
+      case RBU_STATE_PROGRESS:
+        pRet->nProgress = sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_CKPT:
+        pRet->iWalCksum = sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_COOKIE:
+        pRet->iCookie = (u32)sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_OALSZ:
+        pRet->iOalSz = sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_PHASEONESTEP:
+        pRet->nPhaseOneStep = sqlite3_column_int64(pStmt, 1);
+        break;
+
+      case RBU_STATE_DATATBL:
+        pRet->zDataTbl = rbuStrndup((char*)sqlite3_column_text(pStmt, 1), &rc);
+        break;
+
+      default:
+        rc = SQLITE_CORRUPT;
+        break;
+    }
+  }
+  rc2 = sqlite3_finalize(pStmt);
+  if( rc==SQLITE_OK ) rc = rc2;
+
+  p->rc = rc;
+  return pRet;
+}
+
+
+/*
+** Open the database handle and attach the RBU database as "rbu". If an
+** error occurs, leave an error code and message in the RBU handle.
+**
+** If argument dbMain is not NULL, then it is a database handle already
+** open on the target database. Use this handle instead of opening a new
+** one.
+*/
+static void rbuOpenDatabase(sqlite3rbu *p, sqlite3 *dbMain, int *pbRetry){
+  assert( p->rc || (p->dbMain==0 && p->dbRbu==0) );
+  assert( p->rc || rbuIsVacuum(p) || p->zTarget!=0 );
+  assert( dbMain==0 || rbuIsVacuum(p)==0 );
+
+  /* Open the RBU database */
+  p->dbRbu = rbuOpenDbhandle(p, p->zRbu, 1);
+  p->dbMain = dbMain;
+
+  if( p->rc==SQLITE_OK && rbuIsVacuum(p) ){
+    sqlite3_file_control(p->dbRbu, "main", SQLITE_FCNTL_RBUCNT, (void*)p);
+    if( p->zState==0 ){
+      const char *zFile = sqlite3_db_filename(p->dbRbu, "main");
+      p->zState = rbuMPrintf(p, "file:///%s-vacuum?modeof=%s", zFile, zFile);
+    }
+  }
+
+  /* If using separate RBU and state databases, attach the state database to
+  ** the RBU db handle now.  */
+  if( p->zState ){
+    rbuMPrintfExec(p, p->dbRbu, "ATTACH %Q AS stat", p->zState);
+    memcpy(p->zStateDb, "stat", 4);
+  }else{
+    memcpy(p->zStateDb, "main", 4);
+  }
+
+#if 0
+  if( p->rc==SQLITE_OK && rbuIsVacuum(p) ){
+    p->rc = sqlite3_exec(p->dbRbu, "BEGIN", 0, 0, 0);
+  }
+#endif
+
+  /* If it has not already been created, create the rbu_state table */
+  rbuMPrintfExec(p, p->dbRbu, RBU_CREATE_STATE, p->zStateDb);
+
+#if 0
+  if( rbuIsVacuum(p) ){
+    if( p->rc==SQLITE_OK ){
+      int rc2;
+      int bOk = 0;
+      sqlite3_stmt *pCnt = 0;
+      p->rc = prepareAndCollectError(p->dbRbu, &pCnt, &p->zErrmsg,
+          "SELECT count(*) FROM stat.sqlite_schema"
+      );
+      if( p->rc==SQLITE_OK
+       && sqlite3_step(pCnt)==SQLITE_ROW
+       && 1==sqlite3_column_int(pCnt, 0)
+      ){
+        bOk = 1;
+      }
+      rc2 = sqlite3_finalize(pCnt);
+      if( p->rc==SQLITE_OK ) p->rc = rc2;
+
+      if( p->rc==SQLITE_OK && bOk==0 ){
+        p->rc = SQLITE_ERROR;
+        p->zErrmsg = sqlite3_mprintf("invalid state database");
+      }
+
+      if( p->rc==SQLITE_OK ){
+        p->rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, 0);
+      }
+    }
+  }
+#endif
+
+  if( p->rc==SQLITE_OK && rbuIsVacuum(p) ){
+    int bOpen = 0;
+    int rc;
+    p->nRbu = 0;
+    p->pRbuFd = 0;
+    rc = sqlite3_file_control(p->dbRbu, "main", SQLITE_FCNTL_RBUCNT, (void*)p);
+    if( rc!=SQLITE_NOTFOUND ) p->rc = rc;
+    if( p->eStage>=RBU_STAGE_MOVE ){
+      bOpen = 1;
+    }else{
+      RbuState *pState = rbuLoadState(p);
+      if( pState ){
+        bOpen = (pState->eStage>=RBU_STAGE_MOVE);
+        rbuFreeState(pState);
+      }
+    }
+    if( bOpen ) p->dbMain = rbuOpenDbhandle(p, p->zRbu, p->nRbu<=1);
+  }
+
+  p->eStage = 0;
+  if( p->rc==SQLITE_OK && p->dbMain==0 ){
+    if( !rbuIsVacuum(p) ){
+      p->dbMain = rbuOpenDbhandle(p, p->zTarget, 1);
+    }else if( p->pRbuFd->pWalFd ){
+      if( pbRetry ){
+        p->pRbuFd->bNolock = 0;
+        sqlite3_close(p->dbRbu);
+        sqlite3_close(p->dbMain);
+        p->dbMain = 0;
+        p->dbRbu = 0;
+        *pbRetry = 1;
+        return;
+      }
+      p->rc = SQLITE_ERROR;
+      p->zErrmsg = sqlite3_mprintf("cannot vacuum wal mode database");
+    }else{
+      char *zTarget;
+      char *zExtra = 0;
+      if( strlen(p->zRbu)>=5 && 0==memcmp("file:", p->zRbu, 5) ){
+        zExtra = &p->zRbu[5];
+        while( *zExtra ){
+          if( *zExtra++=='?' ) break;
+        }
+        if( *zExtra=='\0' ) zExtra = 0;
+      }
+
+      zTarget = sqlite3_mprintf("file:%s-vactmp?rbu_memory=1%s%s",
+          sqlite3_db_filename(p->dbRbu, "main"),
+          (zExtra==0 ? "" : "&"), (zExtra==0 ? "" : zExtra)
+      );
+
+      if( zTarget==0 ){
+        p->rc = SQLITE_NOMEM;
+        return;
+      }
+      p->dbMain = rbuOpenDbhandle(p, zTarget, p->nRbu<=1);
+      sqlite3_free(zTarget);
+    }
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_create_function(p->dbMain,
+        "rbu_tmp_insert", -1, SQLITE_UTF8, (void*)p, rbuTmpInsertFunc, 0, 0
+    );
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_create_function(p->dbMain,
+        "rbu_fossil_delta", 2, SQLITE_UTF8, 0, rbuFossilDeltaFunc, 0, 0
+    );
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_create_function(p->dbRbu,
+        "rbu_target_name", -1, SQLITE_UTF8, (void*)p, rbuTargetNameFunc, 0, 0
+    );
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_file_control(p->dbMain, "main", SQLITE_FCNTL_RBU, (void*)p);
+  }
+  rbuMPrintfExec(p, p->dbMain, "SELECT * FROM sqlite_schema");
+
+  /* Mark the database file just opened as an RBU target database. If
+  ** this call returns SQLITE_NOTFOUND, then the RBU vfs is not in use.
+  ** This is an error.  */
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_file_control(p->dbMain, "main", SQLITE_FCNTL_RBU, (void*)p);
+  }
+
+  if( p->rc==SQLITE_NOTFOUND ){
+    p->rc = SQLITE_ERROR;
+    p->zErrmsg = sqlite3_mprintf("rbu vfs not found");
+  }
+}
+
+/*
+** This routine is a copy of the sqlite3FileSuffix3() routine from the core.
+** It is a no-op unless SQLITE_ENABLE_8_3_NAMES is defined.
+**
+** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
+** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
+** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
+** three characters, then shorten the suffix on z[] to be the last three
+** characters of the original suffix.
+**
+** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
+** do the suffix shortening regardless of URI parameter.
+**
+** Examples:
+**
+**     test.db-journal    =>   test.nal
+**     test.db-wal        =>   test.wal
+**     test.db-shm        =>   test.shm
+**     test.db-mj7f3319fa =>   test.9fa
+*/
+static void rbuFileSuffix3(const char *zBase, char *z){
+#ifdef SQLITE_ENABLE_8_3_NAMES
+#if SQLITE_ENABLE_8_3_NAMES<2
+  if( sqlite3_uri_boolean(zBase, "8_3_names", 0) )
+#endif
+  {
+    int i, sz;
+    sz = (int)strlen(z)&0xffffff;
+    for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
+    if( z[i]=='.' && sz>i+4 ) memmove(&z[i+1], &z[sz-3], 4);
+  }
+#else
+  UNUSED_PARAMETER2(zBase,z);
+#endif
+}
+
+/*
+** Return the current wal-index header checksum for the target database
+** as a 64-bit integer.
+**
+** The checksum is store in the first page of xShmMap memory as an 8-byte
+** blob starting at byte offset 40.
+*/
+static i64 rbuShmChecksum(sqlite3rbu *p){
+  i64 iRet = 0;
+  if( p->rc==SQLITE_OK ){
+    sqlite3_file *pDb = p->pTargetFd->pReal;
+    u32 volatile *ptr;
+    p->rc = pDb->pMethods->xShmMap(pDb, 0, 32*1024, 0, (void volatile**)&ptr);
+    if( p->rc==SQLITE_OK ){
+      iRet = (i64)(((u64)ptr[10] << 32) + ptr[11]);
+    }
+  }
+  return iRet;
+}
+
+/*
+** This function is called as part of initializing or reinitializing an
+** incremental checkpoint.
+**
+** It populates the sqlite3rbu.aFrame[] array with the set of
+** (wal frame -> db page) copy operations required to checkpoint the
+** current wal file, and obtains the set of shm locks required to safely
+** perform the copy operations directly on the file-system.
+**
+** If argument pState is not NULL, then the incremental checkpoint is
+** being resumed. In this case, if the checksum of the wal-index-header
+** following recovery is not the same as the checksum saved in the RbuState
+** object, then the rbu handle is set to DONE state. This occurs if some
+** other client appends a transaction to the wal file in the middle of
+** an incremental checkpoint.
+*/
+static void rbuSetupCheckpoint(sqlite3rbu *p, RbuState *pState){
+
+  /* If pState is NULL, then the wal file may not have been opened and
+  ** recovered. Running a read-statement here to ensure that doing so
+  ** does not interfere with the "capture" process below.  */
+  if( pState==0 ){
+    p->eStage = 0;
+    if( p->rc==SQLITE_OK ){
+      p->rc = sqlite3_exec(p->dbMain, "SELECT * FROM sqlite_schema", 0, 0, 0);
+    }
+  }
+
+  /* Assuming no error has occurred, run a "restart" checkpoint with the
+  ** sqlite3rbu.eStage variable set to CAPTURE. This turns on the following
+  ** special behaviour in the rbu VFS:
+  **
+  **   * If the exclusive shm WRITER or READ0 lock cannot be obtained,
+  **     the checkpoint fails with SQLITE_BUSY (normally SQLite would
+  **     proceed with running a passive checkpoint instead of failing).
+  **
+  **   * Attempts to read from the *-wal file or write to the database file
+  **     do not perform any IO. Instead, the frame/page combinations that
+  **     would be read/written are recorded in the sqlite3rbu.aFrame[]
+  **     array.
+  **
+  **   * Calls to xShmLock(UNLOCK) to release the exclusive shm WRITER,
+  **     READ0 and CHECKPOINT locks taken as part of the checkpoint are
+  **     no-ops. These locks will not be released until the connection
+  **     is closed.
+  **
+  **   * Attempting to xSync() the database file causes an SQLITE_NOTICE
+  **     error.
+  **
+  ** As a result, unless an error (i.e. OOM or SQLITE_BUSY) occurs, the
+  ** checkpoint below fails with SQLITE_NOTICE, and leaves the aFrame[]
+  ** array populated with a set of (frame -> page) mappings. Because the
+  ** WRITER, CHECKPOINT and READ0 locks are still held, it is safe to copy
+  ** data from the wal file into the database file according to the
+  ** contents of aFrame[].
+  */
+  if( p->rc==SQLITE_OK ){
+    int rc2;
+    p->eStage = RBU_STAGE_CAPTURE;
+    rc2 = sqlite3_exec(p->dbMain, "PRAGMA main.wal_checkpoint=restart", 0, 0,0);
+    if( rc2!=SQLITE_NOTICE ) p->rc = rc2;
+  }
+
+  if( p->rc==SQLITE_OK && p->nFrame>0 ){
+    p->eStage = RBU_STAGE_CKPT;
+    p->nStep = (pState ? pState->nRow : 0);
+    p->aBuf = rbuMalloc(p, p->pgsz);
+    p->iWalCksum = rbuShmChecksum(p);
+  }
+
+  if( p->rc==SQLITE_OK ){
+    if( p->nFrame==0 || (pState && pState->iWalCksum!=p->iWalCksum) ){
+      p->rc = SQLITE_DONE;
+      p->eStage = RBU_STAGE_DONE;
+    }else{
+      int nSectorSize;
+      sqlite3_file *pDb = p->pTargetFd->pReal;
+      sqlite3_file *pWal = p->pTargetFd->pWalFd->pReal;
+      assert( p->nPagePerSector==0 );
+      nSectorSize = pDb->pMethods->xSectorSize(pDb);
+      if( nSectorSize>p->pgsz ){
+        p->nPagePerSector = nSectorSize / p->pgsz;
+      }else{
+        p->nPagePerSector = 1;
+      }
+
+      /* Call xSync() on the wal file. This causes SQLite to sync the
+      ** directory in which the target database and the wal file reside, in
+      ** case it has not been synced since the rename() call in
+      ** rbuMoveOalFile(). */
+      p->rc = pWal->pMethods->xSync(pWal, SQLITE_SYNC_NORMAL);
+    }
+  }
+}
+
+/*
+** Called when iAmt bytes are read from offset iOff of the wal file while
+** the rbu object is in capture mode. Record the frame number of the frame
+** being read in the aFrame[] array.
+*/
+static int rbuCaptureWalRead(sqlite3rbu *pRbu, i64 iOff, int iAmt){
+  const u32 mReq = (1<<WAL_LOCK_WRITE)|(1<<WAL_LOCK_CKPT)|(1<<WAL_LOCK_READ0);
+  u32 iFrame;
+
+  if( pRbu->mLock!=mReq ){
+    pRbu->rc = SQLITE_BUSY;
+    return SQLITE_NOTICE_RBU;
+  }
+
+  pRbu->pgsz = iAmt;
+  if( pRbu->nFrame==pRbu->nFrameAlloc ){
+    int nNew = (pRbu->nFrameAlloc ? pRbu->nFrameAlloc : 64) * 2;
+    RbuFrame *aNew;
+    aNew = (RbuFrame*)sqlite3_realloc64(pRbu->aFrame, nNew * sizeof(RbuFrame));
+    if( aNew==0 ) return SQLITE_NOMEM;
+    pRbu->aFrame = aNew;
+    pRbu->nFrameAlloc = nNew;
+  }
+
+  iFrame = (u32)((iOff-32) / (i64)(iAmt+24)) + 1;
+  if( pRbu->iMaxFrame<iFrame ) pRbu->iMaxFrame = iFrame;
+  pRbu->aFrame[pRbu->nFrame].iWalFrame = iFrame;
+  pRbu->aFrame[pRbu->nFrame].iDbPage = 0;
+  pRbu->nFrame++;
+  return SQLITE_OK;
+}
+
+/*
+** Called when a page of data is written to offset iOff of the database
+** file while the rbu handle is in capture mode. Record the page number
+** of the page being written in the aFrame[] array.
+*/
+static int rbuCaptureDbWrite(sqlite3rbu *pRbu, i64 iOff){
+  pRbu->aFrame[pRbu->nFrame-1].iDbPage = (u32)(iOff / pRbu->pgsz) + 1;
+  return SQLITE_OK;
+}
+
+/*
+** This is called as part of an incremental checkpoint operation. Copy
+** a single frame of data from the wal file into the database file, as
+** indicated by the RbuFrame object.
+*/
+static void rbuCheckpointFrame(sqlite3rbu *p, RbuFrame *pFrame){
+  sqlite3_file *pWal = p->pTargetFd->pWalFd->pReal;
+  sqlite3_file *pDb = p->pTargetFd->pReal;
+  i64 iOff;
+
+  assert( p->rc==SQLITE_OK );
+  iOff = (i64)(pFrame->iWalFrame-1) * (p->pgsz + 24) + 32 + 24;
+  p->rc = pWal->pMethods->xRead(pWal, p->aBuf, p->pgsz, iOff);
+  if( p->rc ) return;
+
+  iOff = (i64)(pFrame->iDbPage-1) * p->pgsz;
+  p->rc = pDb->pMethods->xWrite(pDb, p->aBuf, p->pgsz, iOff);
+}
+
+/*
+** This value is copied from the definition of ZIPVFS_CTRL_FILE_POINTER
+** in zipvfs.h.
+*/
+#define RBU_ZIPVFS_CTRL_FILE_POINTER 230439
+
+/*
+** Take an EXCLUSIVE lock on the database file. Return SQLITE_OK if
+** successful, or an SQLite error code otherwise.
+*/
+static int rbuLockDatabase(sqlite3 *db){
+  int rc = SQLITE_OK;
+  sqlite3_file *fd = 0;
+
+  sqlite3_file_control(db, "main", RBU_ZIPVFS_CTRL_FILE_POINTER, &fd);
+  if( fd ){
+    sqlite3_file_control(db, "main", SQLITE_FCNTL_FILE_POINTER, &fd);
+    rc = fd->pMethods->xLock(fd, SQLITE_LOCK_SHARED);
+    if( rc==SQLITE_OK ){
+      rc = fd->pMethods->xUnlock(fd, SQLITE_LOCK_NONE);
+    }
+    sqlite3_file_control(db, "main", RBU_ZIPVFS_CTRL_FILE_POINTER, &fd);
+  }else{
+    sqlite3_file_control(db, "main", SQLITE_FCNTL_FILE_POINTER, &fd);
+  }
+
+  if( rc==SQLITE_OK && fd->pMethods ){
+    rc = fd->pMethods->xLock(fd, SQLITE_LOCK_SHARED);
+    if( rc==SQLITE_OK ){
+      rc = fd->pMethods->xLock(fd, SQLITE_LOCK_EXCLUSIVE);
+    }
+  }
+  return rc;
+}
+
+/*
+** Return true if the database handle passed as the only argument
+** was opened with the rbu_exclusive_checkpoint=1 URI parameter
+** specified. Or false otherwise.
+*/
+static int rbuExclusiveCheckpoint(sqlite3 *db){
+  const char *zUri = sqlite3_db_filename(db, 0);
+  return sqlite3_uri_boolean(zUri, RBU_EXCLUSIVE_CHECKPOINT, 0);
+}
+
+#if defined(_WIN32_WCE)
+static LPWSTR rbuWinUtf8ToUnicode(const char *zFilename){
+  int nChar;
+  LPWSTR zWideFilename;
+
+  nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0);
+  if( nChar==0 ){
+    return 0;
+  }
+  zWideFilename = sqlite3_malloc64( nChar*sizeof(zWideFilename[0]) );
+  if( zWideFilename==0 ){
+    return 0;
+  }
+  memset(zWideFilename, 0, nChar*sizeof(zWideFilename[0]));
+  nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, zWideFilename,
+                                nChar);
+  if( nChar==0 ){
+    sqlite3_free(zWideFilename);
+    zWideFilename = 0;
+  }
+  return zWideFilename;
+}
+#endif
+
+/*
+** The RBU handle is currently in RBU_STAGE_OAL state, with a SHARED lock
+** on the database file. This proc moves the *-oal file to the *-wal path,
+** then reopens the database file (this time in vanilla, non-oal, WAL mode).
+** If an error occurs, leave an error code and error message in the rbu
+** handle.
+*/
+static void rbuMoveOalFile(sqlite3rbu *p){
+  const char *zBase = sqlite3_db_filename(p->dbMain, "main");
+  const char *zMove = zBase;
+  char *zOal;
+  char *zWal;
+
+  if( rbuIsVacuum(p) ){
+    zMove = sqlite3_db_filename(p->dbRbu, "main");
+  }
+  zOal = sqlite3_mprintf("%s-oal", zMove);
+  zWal = sqlite3_mprintf("%s-wal", zMove);
+
+  assert( p->eStage==RBU_STAGE_MOVE );
+  assert( p->rc==SQLITE_OK && p->zErrmsg==0 );
+  if( zWal==0 || zOal==0 ){
+    p->rc = SQLITE_NOMEM;
+  }else{
+    /* Move the *-oal file to *-wal. At this point connection p->db is
+    ** holding a SHARED lock on the target database file (because it is
+    ** in WAL mode). So no other connection may be writing the db.
+    **
+    ** In order to ensure that there are no database readers, an EXCLUSIVE
+    ** lock is obtained here before the *-oal is moved to *-wal.
+    */
+    sqlite3 *dbMain = 0;
+    rbuFileSuffix3(zBase, zWal);
+    rbuFileSuffix3(zBase, zOal);
+
+    /* Re-open the databases. */
+    rbuObjIterFinalize(&p->objiter);
+    sqlite3_close(p->dbRbu);
+    sqlite3_close(p->dbMain);
+    p->dbMain = 0;
+    p->dbRbu = 0;
+
+    dbMain = rbuOpenDbhandle(p, p->zTarget, 1);
+    if( dbMain ){
+      assert( p->rc==SQLITE_OK );
+      p->rc = rbuLockDatabase(dbMain);
+    }
+
+    if( p->rc==SQLITE_OK ){
+      p->rc = p->xRename(p->pRenameArg, zOal, zWal);
+    }
+
+    if( p->rc!=SQLITE_OK
+     || rbuIsVacuum(p)
+     || rbuExclusiveCheckpoint(dbMain)==0
+    ){
+      sqlite3_close(dbMain);
+      dbMain = 0;
+    }
+
+    if( p->rc==SQLITE_OK ){
+      rbuOpenDatabase(p, dbMain, 0);
+      rbuSetupCheckpoint(p, 0);
+    }
+  }
+
+  sqlite3_free(zWal);
+  sqlite3_free(zOal);
+}
+
+/*
+** The SELECT statement iterating through the keys for the current object
+** (p->objiter.pSelect) currently points to a valid row. This function
+** determines the type of operation requested by this row and returns
+** one of the following values to indicate the result:
+**
+**     * RBU_INSERT
+**     * RBU_DELETE
+**     * RBU_IDX_DELETE
+**     * RBU_UPDATE
+**
+** If RBU_UPDATE is returned, then output variable *pzMask is set to
+** point to the text value indicating the columns to update.
+**
+** If the rbu_control field contains an invalid value, an error code and
+** message are left in the RBU handle and zero returned.
+*/
+static int rbuStepType(sqlite3rbu *p, const char **pzMask){
+  int iCol = p->objiter.nCol;     /* Index of rbu_control column */
+  int res = 0;                    /* Return value */
+
+  switch( sqlite3_column_type(p->objiter.pSelect, iCol) ){
+    case SQLITE_INTEGER: {
+      int iVal = sqlite3_column_int(p->objiter.pSelect, iCol);
+      switch( iVal ){
+        case 0: res = RBU_INSERT;     break;
+        case 1: res = RBU_DELETE;     break;
+        case 2: res = RBU_REPLACE;    break;
+        case 3: res = RBU_IDX_DELETE; break;
+        case 4: res = RBU_IDX_INSERT; break;
+      }
+      break;
+    }
+
+    case SQLITE_TEXT: {
+      const unsigned char *z = sqlite3_column_text(p->objiter.pSelect, iCol);
+      if( z==0 ){
+        p->rc = SQLITE_NOMEM;
+      }else{
+        *pzMask = (const char*)z;
+      }
+      res = RBU_UPDATE;
+
+      break;
+    }
+
+    default:
+      break;
+  }
+
+  if( res==0 ){
+    rbuBadControlError(p);
+  }
+  return res;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Assert that column iCol of statement pStmt is named zName.
+*/
+static void assertColumnName(sqlite3_stmt *pStmt, int iCol, const char *zName){
+  const char *zCol = sqlite3_column_name(pStmt, iCol);
+  assert( 0==sqlite3_stricmp(zName, zCol) );
+}
+#else
+# define assertColumnName(x,y,z)
+#endif
+
+/*
+** Argument eType must be one of RBU_INSERT, RBU_DELETE, RBU_IDX_INSERT or
+** RBU_IDX_DELETE. This function performs the work of a single
+** sqlite3rbu_step() call for the type of operation specified by eType.
+*/
+static void rbuStepOneOp(sqlite3rbu *p, int eType){
+  RbuObjIter *pIter = &p->objiter;
+  sqlite3_value *pVal;
+  sqlite3_stmt *pWriter;
+  int i;
+
+  assert( p->rc==SQLITE_OK );
+  assert( eType!=RBU_DELETE || pIter->zIdx==0 );
+  assert( eType==RBU_DELETE || eType==RBU_IDX_DELETE
+       || eType==RBU_INSERT || eType==RBU_IDX_INSERT
+  );
+
+  /* If this is a delete, decrement nPhaseOneStep by nIndex. If the DELETE
+  ** statement below does actually delete a row, nPhaseOneStep will be
+  ** incremented by the same amount when SQL function rbu_tmp_insert()
+  ** is invoked by the trigger.  */
+  if( eType==RBU_DELETE ){
+    p->nPhaseOneStep -= p->objiter.nIndex;
+  }
+
+  if( eType==RBU_IDX_DELETE || eType==RBU_DELETE ){
+    pWriter = pIter->pDelete;
+  }else{
+    pWriter = pIter->pInsert;
+  }
+
+  for(i=0; i<pIter->nCol; i++){
+    /* If this is an INSERT into a table b-tree and the table has an
+    ** explicit INTEGER PRIMARY KEY, check that this is not an attempt
+    ** to write a NULL into the IPK column. That is not permitted.  */
+    if( eType==RBU_INSERT
+     && pIter->zIdx==0 && pIter->eType==RBU_PK_IPK && pIter->abTblPk[i]
+     && sqlite3_column_type(pIter->pSelect, i)==SQLITE_NULL
+    ){
+      p->rc = SQLITE_MISMATCH;
+      p->zErrmsg = sqlite3_mprintf("datatype mismatch");
+      return;
+    }
+
+    if( eType==RBU_DELETE && pIter->abTblPk[i]==0 ){
+      continue;
+    }
+
+    pVal = sqlite3_column_value(pIter->pSelect, i);
+    p->rc = sqlite3_bind_value(pWriter, i+1, pVal);
+    if( p->rc ) return;
+  }
+  if( pIter->zIdx==0 ){
+    if( pIter->eType==RBU_PK_VTAB
+     || pIter->eType==RBU_PK_NONE
+     || (pIter->eType==RBU_PK_EXTERNAL && rbuIsVacuum(p))
+    ){
+      /* For a virtual table, or a table with no primary key, the
+      ** SELECT statement is:
+      **
+      **   SELECT <cols>, rbu_control, rbu_rowid FROM ....
+      **
+      ** Hence column_value(pIter->nCol+1).
+      */
+      assertColumnName(pIter->pSelect, pIter->nCol+1,
+          rbuIsVacuum(p) ? "rowid" : "rbu_rowid"
+      );
+      pVal = sqlite3_column_value(pIter->pSelect, pIter->nCol+1);
+      p->rc = sqlite3_bind_value(pWriter, pIter->nCol+1, pVal);
+    }
+  }
+  if( p->rc==SQLITE_OK ){
+    sqlite3_step(pWriter);
+    p->rc = resetAndCollectError(pWriter, &p->zErrmsg);
+  }
+}
+
+/*
+** This function does the work for an sqlite3rbu_step() call.
+**
+** The object-iterator (p->objiter) currently points to a valid object,
+** and the input cursor (p->objiter.pSelect) currently points to a valid
+** input row. Perform whatever processing is required and return.
+**
+** If no  error occurs, SQLITE_OK is returned. Otherwise, an error code
+** and message is left in the RBU handle and a copy of the error code
+** returned.
+*/
+static int rbuStep(sqlite3rbu *p){
+  RbuObjIter *pIter = &p->objiter;
+  const char *zMask = 0;
+  int eType = rbuStepType(p, &zMask);
+
+  if( eType ){
+    assert( eType==RBU_INSERT     || eType==RBU_DELETE
+         || eType==RBU_REPLACE    || eType==RBU_IDX_DELETE
+         || eType==RBU_IDX_INSERT || eType==RBU_UPDATE
+    );
+    assert( eType!=RBU_UPDATE || pIter->zIdx==0 );
+
+    if( pIter->zIdx==0 && (eType==RBU_IDX_DELETE || eType==RBU_IDX_INSERT) ){
+      rbuBadControlError(p);
+    }
+    else if( eType==RBU_REPLACE ){
+      if( pIter->zIdx==0 ){
+        p->nPhaseOneStep += p->objiter.nIndex;
+        rbuStepOneOp(p, RBU_DELETE);
+      }
+      if( p->rc==SQLITE_OK ) rbuStepOneOp(p, RBU_INSERT);
+    }
+    else if( eType!=RBU_UPDATE ){
+      rbuStepOneOp(p, eType);
+    }
+    else{
+      sqlite3_value *pVal;
+      sqlite3_stmt *pUpdate = 0;
+      assert( eType==RBU_UPDATE );
+      p->nPhaseOneStep -= p->objiter.nIndex;
+      rbuGetUpdateStmt(p, pIter, zMask, &pUpdate);
+      if( pUpdate ){
+        int i;
+        for(i=0; p->rc==SQLITE_OK && i<pIter->nCol; i++){
+          char c = zMask[pIter->aiSrcOrder[i]];
+          pVal = sqlite3_column_value(pIter->pSelect, i);
+          if( pIter->abTblPk[i] || c!='.' ){
+            p->rc = sqlite3_bind_value(pUpdate, i+1, pVal);
+          }
+        }
+        if( p->rc==SQLITE_OK
+         && (pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE)
+        ){
+          /* Bind the rbu_rowid value to column _rowid_ */
+          assertColumnName(pIter->pSelect, pIter->nCol+1, "rbu_rowid");
+          pVal = sqlite3_column_value(pIter->pSelect, pIter->nCol+1);
+          p->rc = sqlite3_bind_value(pUpdate, pIter->nCol+1, pVal);
+        }
+        if( p->rc==SQLITE_OK ){
+          sqlite3_step(pUpdate);
+          p->rc = resetAndCollectError(pUpdate, &p->zErrmsg);
+        }
+      }
+    }
+  }
+  return p->rc;
+}
+
+/*
+** Increment the schema cookie of the main database opened by p->dbMain.
+**
+** Or, if this is an RBU vacuum, set the schema cookie of the main db
+** opened by p->dbMain to one more than the schema cookie of the main
+** db opened by p->dbRbu.
+*/
+static void rbuIncrSchemaCookie(sqlite3rbu *p){
+  if( p->rc==SQLITE_OK ){
+    sqlite3 *dbread = (rbuIsVacuum(p) ? p->dbRbu : p->dbMain);
+    int iCookie = 1000000;
+    sqlite3_stmt *pStmt;
+
+    p->rc = prepareAndCollectError(dbread, &pStmt, &p->zErrmsg,
+        "PRAGMA schema_version"
+    );
+    if( p->rc==SQLITE_OK ){
+      /* Coverage: it may be that this sqlite3_step() cannot fail. There
+      ** is already a transaction open, so the prepared statement cannot
+      ** throw an SQLITE_SCHEMA exception. The only database page the
+      ** statement reads is page 1, which is guaranteed to be in the cache.
+      ** And no memory allocations are required.  */
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        iCookie = sqlite3_column_int(pStmt, 0);
+      }
+      rbuFinalize(p, pStmt);
+    }
+    if( p->rc==SQLITE_OK ){
+      rbuMPrintfExec(p, p->dbMain, "PRAGMA schema_version = %d", iCookie+1);
+    }
+  }
+}
+
+/*
+** Update the contents of the rbu_state table within the rbu database. The
+** value stored in the RBU_STATE_STAGE column is eStage. All other values
+** are determined by inspecting the rbu handle passed as the first argument.
+*/
+static void rbuSaveState(sqlite3rbu *p, int eStage){
+  if( p->rc==SQLITE_OK || p->rc==SQLITE_DONE ){
+    sqlite3_stmt *pInsert = 0;
+    rbu_file *pFd = (rbuIsVacuum(p) ? p->pRbuFd : p->pTargetFd);
+    int rc;
+
+    assert( p->zErrmsg==0 );
+    rc = prepareFreeAndCollectError(p->dbRbu, &pInsert, &p->zErrmsg,
+        sqlite3_mprintf(
+          "INSERT OR REPLACE INTO %s.rbu_state(k, v) VALUES "
+          "(%d, %d), "
+          "(%d, %Q), "
+          "(%d, %Q), "
+          "(%d, %d), "
+          "(%d, %lld), "
+          "(%d, %lld), "
+          "(%d, %lld), "
+          "(%d, %lld), "
+          "(%d, %lld), "
+          "(%d, %Q)  ",
+          p->zStateDb,
+          RBU_STATE_STAGE, eStage,
+          RBU_STATE_TBL, p->objiter.zTbl,
+          RBU_STATE_IDX, p->objiter.zIdx,
+          RBU_STATE_ROW, p->nStep,
+          RBU_STATE_PROGRESS, p->nProgress,
+          RBU_STATE_CKPT, p->iWalCksum,
+          RBU_STATE_COOKIE, (i64)pFd->iCookie,
+          RBU_STATE_OALSZ, p->iOalSz,
+          RBU_STATE_PHASEONESTEP, p->nPhaseOneStep,
+          RBU_STATE_DATATBL, p->objiter.zDataTbl
+      )
+    );
+    assert( pInsert==0 || rc==SQLITE_OK );
+
+    if( rc==SQLITE_OK ){
+      sqlite3_step(pInsert);
+      rc = sqlite3_finalize(pInsert);
+    }
+    if( rc!=SQLITE_OK ) p->rc = rc;
+  }
+}
+
+
+/*
+** The second argument passed to this function is the name of a PRAGMA
+** setting - "page_size", "auto_vacuum", "user_version" or "application_id".
+** This function executes the following on sqlite3rbu.dbRbu:
+**
+**   "PRAGMA main.$zPragma"
+**
+** where $zPragma is the string passed as the second argument, then
+** on sqlite3rbu.dbMain:
+**
+**   "PRAGMA main.$zPragma = $val"
+**
+** where $val is the value returned by the first PRAGMA invocation.
+**
+** In short, it copies the value  of the specified PRAGMA setting from
+** dbRbu to dbMain.
+*/
+static void rbuCopyPragma(sqlite3rbu *p, const char *zPragma){
+  if( p->rc==SQLITE_OK ){
+    sqlite3_stmt *pPragma = 0;
+    p->rc = prepareFreeAndCollectError(p->dbRbu, &pPragma, &p->zErrmsg,
+        sqlite3_mprintf("PRAGMA main.%s", zPragma)
+    );
+    if( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pPragma) ){
+      p->rc = rbuMPrintfExec(p, p->dbMain, "PRAGMA main.%s = %d",
+          zPragma, sqlite3_column_int(pPragma, 0)
+      );
+    }
+    rbuFinalize(p, pPragma);
+  }
+}
+
+/*
+** The RBU handle passed as the only argument has just been opened and
+** the state database is empty. If this RBU handle was opened for an
+** RBU vacuum operation, create the schema in the target db.
+*/
+static void rbuCreateTargetSchema(sqlite3rbu *p){
+  sqlite3_stmt *pSql = 0;
+  sqlite3_stmt *pInsert = 0;
+
+  assert( rbuIsVacuum(p) );
+  p->rc = sqlite3_exec(p->dbMain, "PRAGMA writable_schema=1", 0,0, &p->zErrmsg);
+  if( p->rc==SQLITE_OK ){
+    p->rc = prepareAndCollectError(p->dbRbu, &pSql, &p->zErrmsg,
+      "SELECT sql FROM sqlite_schema WHERE sql!='' AND rootpage!=0"
+      " AND name!='sqlite_sequence' "
+      " ORDER BY type DESC"
+    );
+  }
+
+  while( p->rc==SQLITE_OK && sqlite3_step(pSql)==SQLITE_ROW ){
+    const char *zSql = (const char*)sqlite3_column_text(pSql, 0);
+    p->rc = sqlite3_exec(p->dbMain, zSql, 0, 0, &p->zErrmsg);
+  }
+  rbuFinalize(p, pSql);
+  if( p->rc!=SQLITE_OK ) return;
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = prepareAndCollectError(p->dbRbu, &pSql, &p->zErrmsg,
+        "SELECT * FROM sqlite_schema WHERE rootpage=0 OR rootpage IS NULL"
+    );
+  }
+
+  if( p->rc==SQLITE_OK ){
+    p->rc = prepareAndCollectError(p->dbMain, &pInsert, &p->zErrmsg,
+        "INSERT INTO sqlite_schema VALUES(?,?,?,?,?)"
+    );
+  }
+
+  while( p->rc==SQLITE_OK && sqlite3_step(pSql)==SQLITE_ROW ){
+    int i;
+    for(i=0; i<5; i++){
+      sqlite3_bind_value(pInsert, i+1, sqlite3_column_value(pSql, i));
+    }
+    sqlite3_step(pInsert);
+    p->rc = sqlite3_reset(pInsert);
+  }
+  if( p->rc==SQLITE_OK ){
+    p->rc = sqlite3_exec(p->dbMain, "PRAGMA writable_schema=0",0,0,&p->zErrmsg);
+  }
+
+  rbuFinalize(p, pSql);
+  rbuFinalize(p, pInsert);
+}
+
+/*
+** Step the RBU object.
+*/
+SQLITE_API int sqlite3rbu_step(sqlite3rbu *p){
+  if( p ){
+    switch( p->eStage ){
+      case RBU_STAGE_OAL: {
+        RbuObjIter *pIter = &p->objiter;
+
+        /* If this is an RBU vacuum operation and the state table was empty
+        ** when this handle was opened, create the target database schema. */
+        if( rbuIsVacuum(p) && p->nProgress==0 && p->rc==SQLITE_OK ){
+          rbuCreateTargetSchema(p);
+          rbuCopyPragma(p, "user_version");
+          rbuCopyPragma(p, "application_id");
+        }
+
+        while( p->rc==SQLITE_OK && pIter->zTbl ){
+
+          if( pIter->bCleanup ){
+            /* Clean up the rbu_tmp_xxx table for the previous table. It
+            ** cannot be dropped as there are currently active SQL statements.
+            ** But the contents can be deleted.  */
+            if( rbuIsVacuum(p)==0 && pIter->abIndexed ){
+              rbuMPrintfExec(p, p->dbRbu,
+                  "DELETE FROM %s.'rbu_tmp_%q'", p->zStateDb, pIter->zDataTbl
+              );
+            }
+          }else{
+            rbuObjIterPrepareAll(p, pIter, 0);
+
+            /* Advance to the next row to process. */
+            if( p->rc==SQLITE_OK ){
+              int rc = sqlite3_step(pIter->pSelect);
+              if( rc==SQLITE_ROW ){
+                p->nProgress++;
+                p->nStep++;
+                return rbuStep(p);
+              }
+              p->rc = sqlite3_reset(pIter->pSelect);
+              p->nStep = 0;
+            }
+          }
+
+          rbuObjIterNext(p, pIter);
+        }
+
+        if( p->rc==SQLITE_OK ){
+          assert( pIter->zTbl==0 );
+          rbuSaveState(p, RBU_STAGE_MOVE);
+          rbuIncrSchemaCookie(p);
+          if( p->rc==SQLITE_OK ){
+            p->rc = sqlite3_exec(p->dbMain, "COMMIT", 0, 0, &p->zErrmsg);
+          }
+          if( p->rc==SQLITE_OK ){
+            p->rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, &p->zErrmsg);
+          }
+          p->eStage = RBU_STAGE_MOVE;
+        }
+        break;
+      }
+
+      case RBU_STAGE_MOVE: {
+        if( p->rc==SQLITE_OK ){
+          rbuMoveOalFile(p);
+          p->nProgress++;
+        }
+        break;
+      }
+
+      case RBU_STAGE_CKPT: {
+        if( p->rc==SQLITE_OK ){
+          if( p->nStep>=p->nFrame ){
+            sqlite3_file *pDb = p->pTargetFd->pReal;
+
+            /* Sync the db file */
+            p->rc = pDb->pMethods->xSync(pDb, SQLITE_SYNC_NORMAL);
+
+            /* Update nBackfill */
+            if( p->rc==SQLITE_OK ){
+              void volatile *ptr;
+              p->rc = pDb->pMethods->xShmMap(pDb, 0, 32*1024, 0, &ptr);
+              if( p->rc==SQLITE_OK ){
+                ((u32 volatile*)ptr)[24] = p->iMaxFrame;
+              }
+            }
+
+            if( p->rc==SQLITE_OK ){
+              p->eStage = RBU_STAGE_DONE;
+              p->rc = SQLITE_DONE;
+            }
+          }else{
+            /* At one point the following block copied a single frame from the
+            ** wal file to the database file. So that one call to sqlite3rbu_step()
+            ** checkpointed a single frame.
+            **
+            ** However, if the sector-size is larger than the page-size, and the
+            ** application calls sqlite3rbu_savestate() or close() immediately
+            ** after this step, then rbu_step() again, then a power failure occurs,
+            ** then the database page written here may be damaged. Work around
+            ** this by checkpointing frames until the next page in the aFrame[]
+            ** lies on a different disk sector to the current one. */
+            u32 iSector;
+            do{
+              RbuFrame *pFrame = &p->aFrame[p->nStep];
+              iSector = (pFrame->iDbPage-1) / p->nPagePerSector;
+              rbuCheckpointFrame(p, pFrame);
+              p->nStep++;
+            }while( p->nStep<p->nFrame
+                 && iSector==((p->aFrame[p->nStep].iDbPage-1) / p->nPagePerSector)
+                 && p->rc==SQLITE_OK
+            );
+          }
+          p->nProgress++;
+        }
+        break;
+      }
+
+      default:
+        break;
+    }
+    return p->rc;
+  }else{
+    return SQLITE_NOMEM;
+  }
+}
+
+/*
+** Compare strings z1 and z2, returning 0 if they are identical, or non-zero
+** otherwise. Either or both argument may be NULL. Two NULL values are
+** considered equal, and NULL is considered distinct from all other values.
+*/
+static int rbuStrCompare(const char *z1, const char *z2){
+  if( z1==0 && z2==0 ) return 0;
+  if( z1==0 || z2==0 ) return 1;
+  return (sqlite3_stricmp(z1, z2)!=0);
+}
+
+/*
+** This function is called as part of sqlite3rbu_open() when initializing
+** an rbu handle in OAL stage. If the rbu update has not started (i.e.
+** the rbu_state table was empty) it is a no-op. Otherwise, it arranges
+** things so that the next call to sqlite3rbu_step() continues on from
+** where the previous rbu handle left off.
+**
+** If an error occurs, an error code and error message are left in the
+** rbu handle passed as the first argument.
+*/
+static void rbuSetupOal(sqlite3rbu *p, RbuState *pState){
+  assert( p->rc==SQLITE_OK );
+  if( pState->zTbl ){
+    RbuObjIter *pIter = &p->objiter;
+    int rc = SQLITE_OK;
+
+    while( rc==SQLITE_OK && pIter->zTbl && (pIter->bCleanup
+       || rbuStrCompare(pIter->zIdx, pState->zIdx)
+       || (pState->zDataTbl==0 && rbuStrCompare(pIter->zTbl, pState->zTbl))
+       || (pState->zDataTbl && rbuStrCompare(pIter->zDataTbl, pState->zDataTbl))
+    )){
+      rc = rbuObjIterNext(p, pIter);
+    }
+
+    if( rc==SQLITE_OK && !pIter->zTbl ){
+      rc = SQLITE_ERROR;
+      p->zErrmsg = sqlite3_mprintf("rbu_state mismatch error");
+    }
+
+    if( rc==SQLITE_OK ){
+      p->nStep = pState->nRow;
+      rc = rbuObjIterPrepareAll(p, &p->objiter, p->nStep);
+    }
+
+    p->rc = rc;
+  }
+}
+
+/*
+** If there is a "*-oal" file in the file-system corresponding to the
+** target database in the file-system, delete it. If an error occurs,
+** leave an error code and error message in the rbu handle.
+*/
+static void rbuDeleteOalFile(sqlite3rbu *p){
+  char *zOal = rbuMPrintf(p, "%s-oal", p->zTarget);
+  if( zOal ){
+    sqlite3_vfs *pVfs = 0;
+    sqlite3_file_control(p->dbMain, "main", SQLITE_FCNTL_VFS_POINTER, &pVfs);
+    assert( pVfs && p->rc==SQLITE_OK && p->zErrmsg==0 );
+    pVfs->xDelete(pVfs, zOal, 0);
+    sqlite3_free(zOal);
+  }
+}
+
+/*
+** Allocate a private rbu VFS for the rbu handle passed as the only
+** argument. This VFS will be used unless the call to sqlite3rbu_open()
+** specified a URI with a vfs=? option in place of a target database
+** file name.
+*/
+static void rbuCreateVfs(sqlite3rbu *p){
+  int rnd;
+  char zRnd[64];
+
+  assert( p->rc==SQLITE_OK );
+  sqlite3_randomness(sizeof(int), (void*)&rnd);
+  sqlite3_snprintf(sizeof(zRnd), zRnd, "rbu_vfs_%d", rnd);
+  p->rc = sqlite3rbu_create_vfs(zRnd, 0);
+  if( p->rc==SQLITE_OK ){
+    sqlite3_vfs *pVfs = sqlite3_vfs_find(zRnd);
+    assert( pVfs );
+    p->zVfsName = pVfs->zName;
+    ((rbu_vfs*)pVfs)->pRbu = p;
+  }
+}
+
+/*
+** Destroy the private VFS created for the rbu handle passed as the only
+** argument by an earlier call to rbuCreateVfs().
+*/
+static void rbuDeleteVfs(sqlite3rbu *p){
+  if( p->zVfsName ){
+    sqlite3rbu_destroy_vfs(p->zVfsName);
+    p->zVfsName = 0;
+  }
+}
+
+/*
+** This user-defined SQL function is invoked with a single argument - the
+** name of a table expected to appear in the target database. It returns
+** the number of auxilliary indexes on the table.
+*/
+static void rbuIndexCntFunc(
+  sqlite3_context *pCtx,
+  int nVal,
+  sqlite3_value **apVal
+){
+  sqlite3rbu *p = (sqlite3rbu*)sqlite3_user_data(pCtx);
+  sqlite3_stmt *pStmt = 0;
+  char *zErrmsg = 0;
+  int rc;
+  sqlite3 *db = (rbuIsVacuum(p) ? p->dbRbu : p->dbMain);
+
+  assert( nVal==1 );
+  UNUSED_PARAMETER(nVal);
+
+  rc = prepareFreeAndCollectError(db, &pStmt, &zErrmsg,
+      sqlite3_mprintf("SELECT count(*) FROM sqlite_schema "
+        "WHERE type='index' AND tbl_name = %Q", sqlite3_value_text(apVal[0]))
+  );
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error(pCtx, zErrmsg, -1);
+  }else{
+    int nIndex = 0;
+    if( SQLITE_ROW==sqlite3_step(pStmt) ){
+      nIndex = sqlite3_column_int(pStmt, 0);
+    }
+    rc = sqlite3_finalize(pStmt);
+    if( rc==SQLITE_OK ){
+      sqlite3_result_int(pCtx, nIndex);
+    }else{
+      sqlite3_result_error(pCtx, sqlite3_errmsg(db), -1);
+    }
+  }
+
+  sqlite3_free(zErrmsg);
+}
+
+/*
+** If the RBU database contains the rbu_count table, use it to initialize
+** the sqlite3rbu.nPhaseOneStep variable. The schema of the rbu_count table
+** is assumed to contain the same columns as:
+**
+**   CREATE TABLE rbu_count(tbl TEXT PRIMARY KEY, cnt INTEGER) WITHOUT ROWID;
+**
+** There should be one row in the table for each data_xxx table in the
+** database. The 'tbl' column should contain the name of a data_xxx table,
+** and the cnt column the number of rows it contains.
+**
+** sqlite3rbu.nPhaseOneStep is initialized to the sum of (1 + nIndex) * cnt
+** for all rows in the rbu_count table, where nIndex is the number of
+** indexes on the corresponding target database table.
+*/
+static void rbuInitPhaseOneSteps(sqlite3rbu *p){
+  if( p->rc==SQLITE_OK ){
+    sqlite3_stmt *pStmt = 0;
+    int bExists = 0;                /* True if rbu_count exists */
+
+    p->nPhaseOneStep = -1;
+
+    p->rc = sqlite3_create_function(p->dbRbu,
+        "rbu_index_cnt", 1, SQLITE_UTF8, (void*)p, rbuIndexCntFunc, 0, 0
+    );
+
+    /* Check for the rbu_count table. If it does not exist, or if an error
+    ** occurs, nPhaseOneStep will be left set to -1. */
+    if( p->rc==SQLITE_OK ){
+      p->rc = prepareAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
+          "SELECT 1 FROM sqlite_schema WHERE tbl_name = 'rbu_count'"
+      );
+    }
+    if( p->rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pStmt) ){
+        bExists = 1;
+      }
+      p->rc = sqlite3_finalize(pStmt);
+    }
+
+    if( p->rc==SQLITE_OK && bExists ){
+      p->rc = prepareAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
+          "SELECT sum(cnt * (1 + rbu_index_cnt(rbu_target_name(tbl))))"
+          "FROM rbu_count"
+      );
+      if( p->rc==SQLITE_OK ){
+        if( SQLITE_ROW==sqlite3_step(pStmt) ){
+          p->nPhaseOneStep = sqlite3_column_int64(pStmt, 0);
+        }
+        p->rc = sqlite3_finalize(pStmt);
+      }
+    }
+  }
+}
+
+
+static sqlite3rbu *openRbuHandle(
+  const char *zTarget,
+  const char *zRbu,
+  const char *zState
+){
+  sqlite3rbu *p;
+  size_t nTarget = zTarget ? strlen(zTarget) : 0;
+  size_t nRbu = strlen(zRbu);
+  size_t nByte = sizeof(sqlite3rbu) + nTarget+1 + nRbu+1;
+
+  p = (sqlite3rbu*)sqlite3_malloc64(nByte);
+  if( p ){
+    RbuState *pState = 0;
+
+    /* Create the custom VFS. */
+    memset(p, 0, sizeof(sqlite3rbu));
+    sqlite3rbu_rename_handler(p, 0, 0);
+    rbuCreateVfs(p);
+
+    /* Open the target, RBU and state databases */
+    if( p->rc==SQLITE_OK ){
+      char *pCsr = (char*)&p[1];
+      int bRetry = 0;
+      if( zTarget ){
+        p->zTarget = pCsr;
+        memcpy(p->zTarget, zTarget, nTarget+1);
+        pCsr += nTarget+1;
+      }
+      p->zRbu = pCsr;
+      memcpy(p->zRbu, zRbu, nRbu+1);
+      pCsr += nRbu+1;
+      if( zState ){
+        p->zState = rbuMPrintf(p, "%s", zState);
+      }
+
+      /* If the first attempt to open the database file fails and the bRetry
+      ** flag it set, this means that the db was not opened because it seemed
+      ** to be a wal-mode db. But, this may have happened due to an earlier
+      ** RBU vacuum operation leaving an old wal file in the directory.
+      ** If this is the case, it will have been checkpointed and deleted
+      ** when the handle was closed and a second attempt to open the
+      ** database may succeed.  */
+      rbuOpenDatabase(p, 0, &bRetry);
+      if( bRetry ){
+        rbuOpenDatabase(p, 0, 0);
+      }
+    }
+
+    if( p->rc==SQLITE_OK ){
+      pState = rbuLoadState(p);
+      assert( pState || p->rc!=SQLITE_OK );
+      if( p->rc==SQLITE_OK ){
+
+        if( pState->eStage==0 ){
+          rbuDeleteOalFile(p);
+          rbuInitPhaseOneSteps(p);
+          p->eStage = RBU_STAGE_OAL;
+        }else{
+          p->eStage = pState->eStage;
+          p->nPhaseOneStep = pState->nPhaseOneStep;
+        }
+        p->nProgress = pState->nProgress;
+        p->iOalSz = pState->iOalSz;
+      }
+    }
+    assert( p->rc!=SQLITE_OK || p->eStage!=0 );
+
+    if( p->rc==SQLITE_OK && p->pTargetFd->pWalFd ){
+      if( p->eStage==RBU_STAGE_OAL ){
+        p->rc = SQLITE_ERROR;
+        p->zErrmsg = sqlite3_mprintf("cannot update wal mode database");
+      }else if( p->eStage==RBU_STAGE_MOVE ){
+        p->eStage = RBU_STAGE_CKPT;
+        p->nStep = 0;
+      }
+    }
+
+    if( p->rc==SQLITE_OK
+     && (p->eStage==RBU_STAGE_OAL || p->eStage==RBU_STAGE_MOVE)
+     && pState->eStage!=0
+    ){
+      rbu_file *pFd = (rbuIsVacuum(p) ? p->pRbuFd : p->pTargetFd);
+      if( pFd->iCookie!=pState->iCookie ){
+        /* At this point (pTargetFd->iCookie) contains the value of the
+        ** change-counter cookie (the thing that gets incremented when a
+        ** transaction is committed in rollback mode) currently stored on
+        ** page 1 of the database file. */
+        p->rc = SQLITE_BUSY;
+        p->zErrmsg = sqlite3_mprintf("database modified during rbu %s",
+            (rbuIsVacuum(p) ? "vacuum" : "update")
+        );
+      }
+    }
+
+    if( p->rc==SQLITE_OK ){
+      if( p->eStage==RBU_STAGE_OAL ){
+        sqlite3 *db = p->dbMain;
+        p->rc = sqlite3_exec(p->dbRbu, "BEGIN", 0, 0, &p->zErrmsg);
+
+        /* Point the object iterator at the first object */
+        if( p->rc==SQLITE_OK ){
+          p->rc = rbuObjIterFirst(p, &p->objiter);
+        }
+
+        /* If the RBU database contains no data_xxx tables, declare the RBU
+        ** update finished.  */
+        if( p->rc==SQLITE_OK && p->objiter.zTbl==0 ){
+          p->rc = SQLITE_DONE;
+          p->eStage = RBU_STAGE_DONE;
+        }else{
+          if( p->rc==SQLITE_OK && pState->eStage==0 && rbuIsVacuum(p) ){
+            rbuCopyPragma(p, "page_size");
+            rbuCopyPragma(p, "auto_vacuum");
+          }
+
+          /* Open transactions both databases. The *-oal file is opened or
+          ** created at this point. */
+          if( p->rc==SQLITE_OK ){
+            p->rc = sqlite3_exec(db, "BEGIN IMMEDIATE", 0, 0, &p->zErrmsg);
+          }
+
+          /* Check if the main database is a zipvfs db. If it is, set the upper
+          ** level pager to use "journal_mode=off". This prevents it from
+          ** generating a large journal using a temp file.  */
+          if( p->rc==SQLITE_OK ){
+            int frc = sqlite3_file_control(db, "main", SQLITE_FCNTL_ZIPVFS, 0);
+            if( frc==SQLITE_OK ){
+              p->rc = sqlite3_exec(
+                db, "PRAGMA journal_mode=off",0,0,&p->zErrmsg);
+            }
+          }
+
+          if( p->rc==SQLITE_OK ){
+            rbuSetupOal(p, pState);
+          }
+        }
+      }else if( p->eStage==RBU_STAGE_MOVE ){
+        /* no-op */
+      }else if( p->eStage==RBU_STAGE_CKPT ){
+        if( !rbuIsVacuum(p) && rbuExclusiveCheckpoint(p->dbMain) ){
+          /* If the rbu_exclusive_checkpoint=1 URI parameter was specified
+          ** and an incremental checkpoint is being resumed, attempt an
+          ** exclusive lock on the db file. If this fails, so be it.  */
+          p->eStage = RBU_STAGE_DONE;
+          rbuLockDatabase(p->dbMain);
+          p->eStage = RBU_STAGE_CKPT;
+        }
+        rbuSetupCheckpoint(p, pState);
+      }else if( p->eStage==RBU_STAGE_DONE ){
+        p->rc = SQLITE_DONE;
+      }else{
+        p->rc = SQLITE_CORRUPT;
+      }
+    }
+
+    rbuFreeState(pState);
+  }
+
+  return p;
+}
+
+/*
+** Allocate and return an RBU handle with all fields zeroed except for the
+** error code, which is set to SQLITE_MISUSE.
+*/
+static sqlite3rbu *rbuMisuseError(void){
+  sqlite3rbu *pRet;
+  pRet = sqlite3_malloc64(sizeof(sqlite3rbu));
+  if( pRet ){
+    memset(pRet, 0, sizeof(sqlite3rbu));
+    pRet->rc = SQLITE_MISUSE;
+  }
+  return pRet;
+}
+
+/*
+** Open and return a new RBU handle.
+*/
+SQLITE_API sqlite3rbu *sqlite3rbu_open(
+  const char *zTarget,
+  const char *zRbu,
+  const char *zState
+){
+  if( zTarget==0 || zRbu==0 ){ return rbuMisuseError(); }
+  return openRbuHandle(zTarget, zRbu, zState);
+}
+
+/*
+** Open a handle to begin or resume an RBU VACUUM operation.
+*/
+SQLITE_API sqlite3rbu *sqlite3rbu_vacuum(
+  const char *zTarget,
+  const char *zState
+){
+  if( zTarget==0 ){ return rbuMisuseError(); }
+  if( zState ){
+    size_t n = strlen(zState);
+    if( n>=7 && 0==memcmp("-vactmp", &zState[n-7], 7) ){
+      return rbuMisuseError();
+    }
+  }
+  /* TODO: Check that both arguments are non-NULL */
+  return openRbuHandle(0, zTarget, zState);
+}
+
+/*
+** Return the database handle used by pRbu.
+*/
+SQLITE_API sqlite3 *sqlite3rbu_db(sqlite3rbu *pRbu, int bRbu){
+  sqlite3 *db = 0;
+  if( pRbu ){
+    db = (bRbu ? pRbu->dbRbu : pRbu->dbMain);
+  }
+  return db;
+}
+
+
+/*
+** If the error code currently stored in the RBU handle is SQLITE_CONSTRAINT,
+** then edit any error message string so as to remove all occurrences of
+** the pattern "rbu_imp_[0-9]*".
+*/
+static void rbuEditErrmsg(sqlite3rbu *p){
+  if( p->rc==SQLITE_CONSTRAINT && p->zErrmsg ){
+    unsigned int i;
+    size_t nErrmsg = strlen(p->zErrmsg);
+    for(i=0; i<(nErrmsg-8); i++){
+      if( memcmp(&p->zErrmsg[i], "rbu_imp_", 8)==0 ){
+        int nDel = 8;
+        while( p->zErrmsg[i+nDel]>='0' && p->zErrmsg[i+nDel]<='9' ) nDel++;
+        memmove(&p->zErrmsg[i], &p->zErrmsg[i+nDel], nErrmsg + 1 - i - nDel);
+        nErrmsg -= nDel;
+      }
+    }
+  }
+}
+
+/*
+** Close the RBU handle.
+*/
+SQLITE_API int sqlite3rbu_close(sqlite3rbu *p, char **pzErrmsg){
+  int rc;
+  if( p ){
+
+    /* Commit the transaction to the *-oal file. */
+    if( p->rc==SQLITE_OK && p->eStage==RBU_STAGE_OAL ){
+      p->rc = sqlite3_exec(p->dbMain, "COMMIT", 0, 0, &p->zErrmsg);
+    }
+
+    /* Sync the db file if currently doing an incremental checkpoint */
+    if( p->rc==SQLITE_OK && p->eStage==RBU_STAGE_CKPT ){
+      sqlite3_file *pDb = p->pTargetFd->pReal;
+      p->rc = pDb->pMethods->xSync(pDb, SQLITE_SYNC_NORMAL);
+    }
+
+    rbuSaveState(p, p->eStage);
+
+    if( p->rc==SQLITE_OK && p->eStage==RBU_STAGE_OAL ){
+      p->rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, &p->zErrmsg);
+    }
+
+    /* Close any open statement handles. */
+    rbuObjIterFinalize(&p->objiter);
+
+    /* If this is an RBU vacuum handle and the vacuum has either finished
+    ** successfully or encountered an error, delete the contents of the
+    ** state table. This causes the next call to sqlite3rbu_vacuum()
+    ** specifying the current target and state databases to start a new
+    ** vacuum from scratch.  */
+    if( rbuIsVacuum(p) && p->rc!=SQLITE_OK && p->dbRbu ){
+      int rc2 = sqlite3_exec(p->dbRbu, "DELETE FROM stat.rbu_state", 0, 0, 0);
+      if( p->rc==SQLITE_DONE && rc2!=SQLITE_OK ) p->rc = rc2;
+    }
+
+    /* Close the open database handle and VFS object. */
+    sqlite3_close(p->dbRbu);
+    sqlite3_close(p->dbMain);
+    assert( p->szTemp==0 );
+    rbuDeleteVfs(p);
+    sqlite3_free(p->aBuf);
+    sqlite3_free(p->aFrame);
+
+    rbuEditErrmsg(p);
+    rc = p->rc;
+    if( pzErrmsg ){
+      *pzErrmsg = p->zErrmsg;
+    }else{
+      sqlite3_free(p->zErrmsg);
+    }
+    sqlite3_free(p->zState);
+    sqlite3_free(p);
+  }else{
+    rc = SQLITE_NOMEM;
+    *pzErrmsg = 0;
+  }
+  return rc;
+}
+
+/*
+** Return the total number of key-value operations (inserts, deletes or
+** updates) that have been performed on the target database since the
+** current RBU update was started.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_progress(sqlite3rbu *pRbu){
+  return pRbu->nProgress;
+}
+
+/*
+** Return permyriadage progress indications for the two main stages of
+** an RBU update.
+*/
+SQLITE_API void sqlite3rbu_bp_progress(sqlite3rbu *p, int *pnOne, int *pnTwo){
+  const int MAX_PROGRESS = 10000;
+  switch( p->eStage ){
+    case RBU_STAGE_OAL:
+      if( p->nPhaseOneStep>0 ){
+        *pnOne = (int)(MAX_PROGRESS * (i64)p->nProgress/(i64)p->nPhaseOneStep);
+      }else{
+        *pnOne = -1;
+      }
+      *pnTwo = 0;
+      break;
+
+    case RBU_STAGE_MOVE:
+      *pnOne = MAX_PROGRESS;
+      *pnTwo = 0;
+      break;
+
+    case RBU_STAGE_CKPT:
+      *pnOne = MAX_PROGRESS;
+      *pnTwo = (int)(MAX_PROGRESS * (i64)p->nStep / (i64)p->nFrame);
+      break;
+
+    case RBU_STAGE_DONE:
+      *pnOne = MAX_PROGRESS;
+      *pnTwo = MAX_PROGRESS;
+      break;
+
+    default:
+      assert( 0 );
+  }
+}
+
+/*
+** Return the current state of the RBU vacuum or update operation.
+*/
+SQLITE_API int sqlite3rbu_state(sqlite3rbu *p){
+  int aRes[] = {
+    0, SQLITE_RBU_STATE_OAL, SQLITE_RBU_STATE_MOVE,
+    0, SQLITE_RBU_STATE_CHECKPOINT, SQLITE_RBU_STATE_DONE
+  };
+
+  assert( RBU_STAGE_OAL==1 );
+  assert( RBU_STAGE_MOVE==2 );
+  assert( RBU_STAGE_CKPT==4 );
+  assert( RBU_STAGE_DONE==5 );
+  assert( aRes[RBU_STAGE_OAL]==SQLITE_RBU_STATE_OAL );
+  assert( aRes[RBU_STAGE_MOVE]==SQLITE_RBU_STATE_MOVE );
+  assert( aRes[RBU_STAGE_CKPT]==SQLITE_RBU_STATE_CHECKPOINT );
+  assert( aRes[RBU_STAGE_DONE]==SQLITE_RBU_STATE_DONE );
+
+  if( p->rc!=SQLITE_OK && p->rc!=SQLITE_DONE ){
+    return SQLITE_RBU_STATE_ERROR;
+  }else{
+    assert( p->rc!=SQLITE_DONE || p->eStage==RBU_STAGE_DONE );
+    assert( p->eStage==RBU_STAGE_OAL
+         || p->eStage==RBU_STAGE_MOVE
+         || p->eStage==RBU_STAGE_CKPT
+         || p->eStage==RBU_STAGE_DONE
+    );
+    return aRes[p->eStage];
+  }
+}
+
+SQLITE_API int sqlite3rbu_savestate(sqlite3rbu *p){
+  int rc = p->rc;
+  if( rc==SQLITE_DONE ) return SQLITE_OK;
+
+  assert( p->eStage>=RBU_STAGE_OAL && p->eStage<=RBU_STAGE_DONE );
+  if( p->eStage==RBU_STAGE_OAL ){
+    assert( rc!=SQLITE_DONE );
+    if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbMain, "COMMIT", 0, 0, 0);
+  }
+
+  /* Sync the db file */
+  if( rc==SQLITE_OK && p->eStage==RBU_STAGE_CKPT ){
+    sqlite3_file *pDb = p->pTargetFd->pReal;
+    rc = pDb->pMethods->xSync(pDb, SQLITE_SYNC_NORMAL);
+  }
+
+  p->rc = rc;
+  rbuSaveState(p, p->eStage);
+  rc = p->rc;
+
+  if( p->eStage==RBU_STAGE_OAL ){
+    assert( rc!=SQLITE_DONE );
+    if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, 0);
+    if( rc==SQLITE_OK ){
+      const char *zBegin = rbuIsVacuum(p) ? "BEGIN" : "BEGIN IMMEDIATE";
+      rc = sqlite3_exec(p->dbRbu, zBegin, 0, 0, 0);
+    }
+    if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbMain, "BEGIN IMMEDIATE", 0, 0,0);
+  }
+
+  p->rc = rc;
+  return rc;
+}
+
+/*
+** Default xRename callback for RBU.
+*/
+static int xDefaultRename(void *pArg, const char *zOld, const char *zNew){
+  int rc = SQLITE_OK;
+  UNUSED_PARAMETER(pArg);
+#if defined(_WIN32_WCE)
+  {
+    LPWSTR zWideOld;
+    LPWSTR zWideNew;
+
+    zWideOld = rbuWinUtf8ToUnicode(zOld);
+    if( zWideOld ){
+      zWideNew = rbuWinUtf8ToUnicode(zNew);
+      if( zWideNew ){
+        if( MoveFileW(zWideOld, zWideNew) ){
+          rc = SQLITE_OK;
+        }else{
+          rc = SQLITE_IOERR;
+        }
+        sqlite3_free(zWideNew);
+      }else{
+        rc = SQLITE_IOERR_NOMEM;
+      }
+      sqlite3_free(zWideOld);
+    }else{
+      rc = SQLITE_IOERR_NOMEM;
+    }
+  }
+#else
+  rc = rename(zOld, zNew) ? SQLITE_IOERR : SQLITE_OK;
+#endif
+  return rc;
+}
+
+SQLITE_API void sqlite3rbu_rename_handler(
+  sqlite3rbu *pRbu,
+  void *pArg,
+  int (*xRename)(void *pArg, const char *zOld, const char *zNew)
+){
+  if( xRename ){
+    pRbu->xRename = xRename;
+    pRbu->pRenameArg = pArg;
+  }else{
+    pRbu->xRename = xDefaultRename;
+    pRbu->pRenameArg = 0;
+  }
+}
+
+/**************************************************************************
+** Beginning of RBU VFS shim methods. The VFS shim modifies the behaviour
+** of a standard VFS in the following ways:
+**
+** 1. Whenever the first page of a main database file is read or
+**    written, the value of the change-counter cookie is stored in
+**    rbu_file.iCookie. Similarly, the value of the "write-version"
+**    database header field is stored in rbu_file.iWriteVer. This ensures
+**    that the values are always trustworthy within an open transaction.
+**
+** 2. Whenever an SQLITE_OPEN_WAL file is opened, the (rbu_file.pWalFd)
+**    member variable of the associated database file descriptor is set
+**    to point to the new file. A mutex protected linked list of all main
+**    db fds opened using a particular RBU VFS is maintained at
+**    rbu_vfs.pMain to facilitate this.
+**
+** 3. Using a new file-control "SQLITE_FCNTL_RBU", a main db rbu_file
+**    object can be marked as the target database of an RBU update. This
+**    turns on the following extra special behaviour:
+**
+** 3a. If xAccess() is called to check if there exists a *-wal file
+**     associated with an RBU target database currently in RBU_STAGE_OAL
+**     stage (preparing the *-oal file), the following special handling
+**     applies:
+**
+**      * if the *-wal file does exist, return SQLITE_CANTOPEN. An RBU
+**        target database may not be in wal mode already.
+**
+**      * if the *-wal file does not exist, set the output parameter to
+**        non-zero (to tell SQLite that it does exist) anyway.
+**
+**     Then, when xOpen() is called to open the *-wal file associated with
+**     the RBU target in RBU_STAGE_OAL stage, instead of opening the *-wal
+**     file, the rbu vfs opens the corresponding *-oal file instead.
+**
+** 3b. The *-shm pages returned by xShmMap() for a target db file in
+**     RBU_STAGE_OAL mode are actually stored in heap memory. This is to
+**     avoid creating a *-shm file on disk. Additionally, xShmLock() calls
+**     are no-ops on target database files in RBU_STAGE_OAL mode. This is
+**     because assert() statements in some VFS implementations fail if
+**     xShmLock() is called before xShmMap().
+**
+** 3c. If an EXCLUSIVE lock is attempted on a target database file in any
+**     mode except RBU_STAGE_DONE (all work completed and checkpointed), it
+**     fails with an SQLITE_BUSY error. This is to stop RBU connections
+**     from automatically checkpointing a *-wal (or *-oal) file from within
+**     sqlite3_close().
+**
+** 3d. In RBU_STAGE_CAPTURE mode, all xRead() calls on the wal file, and
+**     all xWrite() calls on the target database file perform no IO.
+**     Instead the frame and page numbers that would be read and written
+**     are recorded. Additionally, successful attempts to obtain exclusive
+**     xShmLock() WRITER, CHECKPOINTER and READ0 locks on the target
+**     database file are recorded. xShmLock() calls to unlock the same
+**     locks are no-ops (so that once obtained, these locks are never
+**     relinquished). Finally, calls to xSync() on the target database
+**     file fail with SQLITE_NOTICE errors.
+*/
+
+static void rbuUnlockShm(rbu_file *p){
+  assert( p->openFlags & SQLITE_OPEN_MAIN_DB );
+  if( p->pRbu ){
+    int (*xShmLock)(sqlite3_file*,int,int,int) = p->pReal->pMethods->xShmLock;
+    int i;
+    for(i=0; i<SQLITE_SHM_NLOCK;i++){
+      if( (1<<i) & p->pRbu->mLock ){
+        xShmLock(p->pReal, i, 1, SQLITE_SHM_UNLOCK|SQLITE_SHM_EXCLUSIVE);
+      }
+    }
+    p->pRbu->mLock = 0;
+  }
+}
+
+/*
+*/
+static int rbuUpdateTempSize(rbu_file *pFd, sqlite3_int64 nNew){
+  sqlite3rbu *pRbu = pFd->pRbu;
+  i64 nDiff = nNew - pFd->sz;
+  pRbu->szTemp += nDiff;
+  pFd->sz = nNew;
+  assert( pRbu->szTemp>=0 );
+  if( pRbu->szTempLimit && pRbu->szTemp>pRbu->szTempLimit ) return SQLITE_FULL;
+  return SQLITE_OK;
+}
+
+/*
+** Add an item to the main-db lists, if it is not already present.
+**
+** There are two main-db lists. One for all file descriptors, and one
+** for all file descriptors with rbu_file.pDb!=0. If the argument has
+** rbu_file.pDb!=0, then it is assumed to already be present on the
+** main list and is only added to the pDb!=0 list.
+*/
+static void rbuMainlistAdd(rbu_file *p){
+  rbu_vfs *pRbuVfs = p->pRbuVfs;
+  rbu_file *pIter;
+  assert( (p->openFlags & SQLITE_OPEN_MAIN_DB) );
+  sqlite3_mutex_enter(pRbuVfs->mutex);
+  if( p->pRbu==0 ){
+    for(pIter=pRbuVfs->pMain; pIter; pIter=pIter->pMainNext);
+    p->pMainNext = pRbuVfs->pMain;
+    pRbuVfs->pMain = p;
+  }else{
+    for(pIter=pRbuVfs->pMainRbu; pIter && pIter!=p; pIter=pIter->pMainRbuNext){}
+    if( pIter==0 ){
+      p->pMainRbuNext = pRbuVfs->pMainRbu;
+      pRbuVfs->pMainRbu = p;
+    }
+  }
+  sqlite3_mutex_leave(pRbuVfs->mutex);
+}
+
+/*
+** Remove an item from the main-db lists.
+*/
+static void rbuMainlistRemove(rbu_file *p){
+  rbu_file **pp;
+  sqlite3_mutex_enter(p->pRbuVfs->mutex);
+  for(pp=&p->pRbuVfs->pMain; *pp && *pp!=p; pp=&((*pp)->pMainNext)){}
+  if( *pp ) *pp = p->pMainNext;
+  p->pMainNext = 0;
+  for(pp=&p->pRbuVfs->pMainRbu; *pp && *pp!=p; pp=&((*pp)->pMainRbuNext)){}
+  if( *pp ) *pp = p->pMainRbuNext;
+  p->pMainRbuNext = 0;
+  sqlite3_mutex_leave(p->pRbuVfs->mutex);
+}
+
+/*
+** Given that zWal points to a buffer containing a wal file name passed to
+** either the xOpen() or xAccess() VFS method, search the main-db list for
+** a file-handle opened by the same database connection on the corresponding
+** database file.
+**
+** If parameter bRbu is true, only search for file-descriptors with
+** rbu_file.pDb!=0.
+*/
+static rbu_file *rbuFindMaindb(rbu_vfs *pRbuVfs, const char *zWal, int bRbu){
+  rbu_file *pDb;
+  sqlite3_mutex_enter(pRbuVfs->mutex);
+  if( bRbu ){
+    for(pDb=pRbuVfs->pMainRbu; pDb && pDb->zWal!=zWal; pDb=pDb->pMainRbuNext){}
+  }else{
+    for(pDb=pRbuVfs->pMain; pDb && pDb->zWal!=zWal; pDb=pDb->pMainNext){}
+  }
+  sqlite3_mutex_leave(pRbuVfs->mutex);
+  return pDb;
+}
+
+/*
+** Close an rbu file.
+*/
+static int rbuVfsClose(sqlite3_file *pFile){
+  rbu_file *p = (rbu_file*)pFile;
+  int rc;
+  int i;
+
+  /* Free the contents of the apShm[] array. And the array itself. */
+  for(i=0; i<p->nShm; i++){
+    sqlite3_free(p->apShm[i]);
+  }
+  sqlite3_free(p->apShm);
+  p->apShm = 0;
+  sqlite3_free(p->zDel);
+
+  if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
+    const sqlite3_io_methods *pMeth = p->pReal->pMethods;
+    rbuMainlistRemove(p);
+    rbuUnlockShm(p);
+    if( pMeth->iVersion>1 && pMeth->xShmUnmap ){
+      pMeth->xShmUnmap(p->pReal, 0);
+    }
+  }
+  else if( (p->openFlags & SQLITE_OPEN_DELETEONCLOSE) && p->pRbu ){
+    rbuUpdateTempSize(p, 0);
+  }
+  assert( p->pMainNext==0 && p->pRbuVfs->pMain!=p );
+
+  /* Close the underlying file handle */
+  rc = p->pReal->pMethods->xClose(p->pReal);
+  return rc;
+}
+
+
+/*
+** Read and return an unsigned 32-bit big-endian integer from the buffer
+** passed as the only argument.
+*/
+static u32 rbuGetU32(u8 *aBuf){
+  return ((u32)aBuf[0] << 24)
+       + ((u32)aBuf[1] << 16)
+       + ((u32)aBuf[2] <<  8)
+       + ((u32)aBuf[3]);
+}
+
+/*
+** Write an unsigned 32-bit value in big-endian format to the supplied
+** buffer.
+*/
+static void rbuPutU32(u8 *aBuf, u32 iVal){
+  aBuf[0] = (iVal >> 24) & 0xFF;
+  aBuf[1] = (iVal >> 16) & 0xFF;
+  aBuf[2] = (iVal >>  8) & 0xFF;
+  aBuf[3] = (iVal >>  0) & 0xFF;
+}
+
+static void rbuPutU16(u8 *aBuf, u16 iVal){
+  aBuf[0] = (iVal >>  8) & 0xFF;
+  aBuf[1] = (iVal >>  0) & 0xFF;
+}
+
+/*
+** Read data from an rbuVfs-file.
+*/
+static int rbuVfsRead(
+  sqlite3_file *pFile,
+  void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  rbu_file *p = (rbu_file*)pFile;
+  sqlite3rbu *pRbu = p->pRbu;
+  int rc;
+
+  if( pRbu && pRbu->eStage==RBU_STAGE_CAPTURE ){
+    assert( p->openFlags & SQLITE_OPEN_WAL );
+    rc = rbuCaptureWalRead(p->pRbu, iOfst, iAmt);
+  }else{
+    if( pRbu && pRbu->eStage==RBU_STAGE_OAL
+     && (p->openFlags & SQLITE_OPEN_WAL)
+     && iOfst>=pRbu->iOalSz
+    ){
+      rc = SQLITE_OK;
+      memset(zBuf, 0, iAmt);
+    }else{
+      rc = p->pReal->pMethods->xRead(p->pReal, zBuf, iAmt, iOfst);
+#if 1
+      /* If this is being called to read the first page of the target
+      ** database as part of an rbu vacuum operation, synthesize the
+      ** contents of the first page if it does not yet exist. Otherwise,
+      ** SQLite will not check for a *-wal file.  */
+      if( pRbu && rbuIsVacuum(pRbu)
+          && rc==SQLITE_IOERR_SHORT_READ && iOfst==0
+          && (p->openFlags & SQLITE_OPEN_MAIN_DB)
+          && pRbu->rc==SQLITE_OK
+      ){
+        sqlite3_file *pFd = (sqlite3_file*)pRbu->pRbuFd;
+        rc = pFd->pMethods->xRead(pFd, zBuf, iAmt, iOfst);
+        if( rc==SQLITE_OK ){
+          u8 *aBuf = (u8*)zBuf;
+          u32 iRoot = rbuGetU32(&aBuf[52]) ? 1 : 0;
+          rbuPutU32(&aBuf[52], iRoot);      /* largest root page number */
+          rbuPutU32(&aBuf[36], 0);          /* number of free pages */
+          rbuPutU32(&aBuf[32], 0);          /* first page on free list trunk */
+          rbuPutU32(&aBuf[28], 1);          /* size of db file in pages */
+          rbuPutU32(&aBuf[24], pRbu->pRbuFd->iCookie+1);  /* Change counter */
+
+          if( iAmt>100 ){
+            memset(&aBuf[100], 0, iAmt-100);
+            rbuPutU16(&aBuf[105], iAmt & 0xFFFF);
+            aBuf[100] = 0x0D;
+          }
+        }
+      }
+#endif
+    }
+    if( rc==SQLITE_OK && iOfst==0 && (p->openFlags & SQLITE_OPEN_MAIN_DB) ){
+      /* These look like magic numbers. But they are stable, as they are part
+       ** of the definition of the SQLite file format, which may not change. */
+      u8 *pBuf = (u8*)zBuf;
+      p->iCookie = rbuGetU32(&pBuf[24]);
+      p->iWriteVer = pBuf[19];
+    }
+  }
+  return rc;
+}
+
+/*
+** Write data to an rbuVfs-file.
+*/
+static int rbuVfsWrite(
+  sqlite3_file *pFile,
+  const void *zBuf,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  rbu_file *p = (rbu_file*)pFile;
+  sqlite3rbu *pRbu = p->pRbu;
+  int rc;
+
+  if( pRbu && pRbu->eStage==RBU_STAGE_CAPTURE ){
+    assert( p->openFlags & SQLITE_OPEN_MAIN_DB );
+    rc = rbuCaptureDbWrite(p->pRbu, iOfst);
+  }else{
+    if( pRbu ){
+      if( pRbu->eStage==RBU_STAGE_OAL
+       && (p->openFlags & SQLITE_OPEN_WAL)
+       && iOfst>=pRbu->iOalSz
+      ){
+        pRbu->iOalSz = iAmt + iOfst;
+      }else if( p->openFlags & SQLITE_OPEN_DELETEONCLOSE ){
+        i64 szNew = iAmt+iOfst;
+        if( szNew>p->sz ){
+          rc = rbuUpdateTempSize(p, szNew);
+          if( rc!=SQLITE_OK ) return rc;
+        }
+      }
+    }
+    rc = p->pReal->pMethods->xWrite(p->pReal, zBuf, iAmt, iOfst);
+    if( rc==SQLITE_OK && iOfst==0 && (p->openFlags & SQLITE_OPEN_MAIN_DB) ){
+      /* These look like magic numbers. But they are stable, as they are part
+      ** of the definition of the SQLite file format, which may not change. */
+      u8 *pBuf = (u8*)zBuf;
+      p->iCookie = rbuGetU32(&pBuf[24]);
+      p->iWriteVer = pBuf[19];
+    }
+  }
+  return rc;
+}
+
+/*
+** Truncate an rbuVfs-file.
+*/
+static int rbuVfsTruncate(sqlite3_file *pFile, sqlite_int64 size){
+  rbu_file *p = (rbu_file*)pFile;
+  if( (p->openFlags & SQLITE_OPEN_DELETEONCLOSE) && p->pRbu ){
+    int rc = rbuUpdateTempSize(p, size);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+  return p->pReal->pMethods->xTruncate(p->pReal, size);
+}
+
+/*
+** Sync an rbuVfs-file.
+*/
+static int rbuVfsSync(sqlite3_file *pFile, int flags){
+  rbu_file *p = (rbu_file *)pFile;
+  if( p->pRbu && p->pRbu->eStage==RBU_STAGE_CAPTURE ){
+    if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
+      return SQLITE_NOTICE_RBU;
+    }
+    return SQLITE_OK;
+  }
+  return p->pReal->pMethods->xSync(p->pReal, flags);
+}
+
+/*
+** Return the current file-size of an rbuVfs-file.
+*/
+static int rbuVfsFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
+  rbu_file *p = (rbu_file *)pFile;
+  int rc;
+  rc = p->pReal->pMethods->xFileSize(p->pReal, pSize);
+
+  /* If this is an RBU vacuum operation and this is the target database,
+  ** pretend that it has at least one page. Otherwise, SQLite will not
+  ** check for the existance of a *-wal file. rbuVfsRead() contains
+  ** similar logic.  */
+  if( rc==SQLITE_OK && *pSize==0
+   && p->pRbu && rbuIsVacuum(p->pRbu)
+   && (p->openFlags & SQLITE_OPEN_MAIN_DB)
+  ){
+    *pSize = 1024;
+  }
+  return rc;
+}
+
+/*
+** Lock an rbuVfs-file.
+*/
+static int rbuVfsLock(sqlite3_file *pFile, int eLock){
+  rbu_file *p = (rbu_file*)pFile;
+  sqlite3rbu *pRbu = p->pRbu;
+  int rc = SQLITE_OK;
+
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
+  if( eLock==SQLITE_LOCK_EXCLUSIVE
+   && (p->bNolock || (pRbu && pRbu->eStage!=RBU_STAGE_DONE))
+  ){
+    /* Do not allow EXCLUSIVE locks. Preventing SQLite from taking this
+    ** prevents it from checkpointing the database from sqlite3_close(). */
+    rc = SQLITE_BUSY;
+  }else{
+    rc = p->pReal->pMethods->xLock(p->pReal, eLock);
+  }
+
+  return rc;
+}
+
+/*
+** Unlock an rbuVfs-file.
+*/
+static int rbuVfsUnlock(sqlite3_file *pFile, int eLock){
+  rbu_file *p = (rbu_file *)pFile;
+  return p->pReal->pMethods->xUnlock(p->pReal, eLock);
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on an rbuVfs-file.
+*/
+static int rbuVfsCheckReservedLock(sqlite3_file *pFile, int *pResOut){
+  rbu_file *p = (rbu_file *)pFile;
+  return p->pReal->pMethods->xCheckReservedLock(p->pReal, pResOut);
+}
+
+/*
+** File control method. For custom operations on an rbuVfs-file.
+*/
+static int rbuVfsFileControl(sqlite3_file *pFile, int op, void *pArg){
+  rbu_file *p = (rbu_file *)pFile;
+  int (*xControl)(sqlite3_file*,int,void*) = p->pReal->pMethods->xFileControl;
+  int rc;
+
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB)
+       || p->openFlags & (SQLITE_OPEN_TRANSIENT_DB|SQLITE_OPEN_TEMP_JOURNAL)
+  );
+  if( op==SQLITE_FCNTL_RBU ){
+    sqlite3rbu *pRbu = (sqlite3rbu*)pArg;
+
+    /* First try to find another RBU vfs lower down in the vfs stack. If
+    ** one is found, this vfs will operate in pass-through mode. The lower
+    ** level vfs will do the special RBU handling.  */
+    rc = xControl(p->pReal, op, pArg);
+
+    if( rc==SQLITE_NOTFOUND ){
+      /* Now search for a zipvfs instance lower down in the VFS stack. If
+      ** one is found, this is an error.  */
+      void *dummy = 0;
+      rc = xControl(p->pReal, SQLITE_FCNTL_ZIPVFS, &dummy);
+      if( rc==SQLITE_OK ){
+        rc = SQLITE_ERROR;
+        pRbu->zErrmsg = sqlite3_mprintf("rbu/zipvfs setup error");
+      }else if( rc==SQLITE_NOTFOUND ){
+        pRbu->pTargetFd = p;
+        p->pRbu = pRbu;
+        rbuMainlistAdd(p);
+        if( p->pWalFd ) p->pWalFd->pRbu = pRbu;
+        rc = SQLITE_OK;
+      }
+    }
+    return rc;
+  }
+  else if( op==SQLITE_FCNTL_RBUCNT ){
+    sqlite3rbu *pRbu = (sqlite3rbu*)pArg;
+    pRbu->nRbu++;
+    pRbu->pRbuFd = p;
+    p->bNolock = 1;
+  }
+
+  rc = xControl(p->pReal, op, pArg);
+  if( rc==SQLITE_OK && op==SQLITE_FCNTL_VFSNAME ){
+    rbu_vfs *pRbuVfs = p->pRbuVfs;
+    char *zIn = *(char**)pArg;
+    char *zOut = sqlite3_mprintf("rbu(%s)/%z", pRbuVfs->base.zName, zIn);
+    *(char**)pArg = zOut;
+    if( zOut==0 ) rc = SQLITE_NOMEM;
+  }
+
+  return rc;
+}
+
+/*
+** Return the sector-size in bytes for an rbuVfs-file.
+*/
+static int rbuVfsSectorSize(sqlite3_file *pFile){
+  rbu_file *p = (rbu_file *)pFile;
+  return p->pReal->pMethods->xSectorSize(p->pReal);
+}
+
+/*
+** Return the device characteristic flags supported by an rbuVfs-file.
+*/
+static int rbuVfsDeviceCharacteristics(sqlite3_file *pFile){
+  rbu_file *p = (rbu_file *)pFile;
+  return p->pReal->pMethods->xDeviceCharacteristics(p->pReal);
+}
+
+/*
+** Take or release a shared-memory lock.
+*/
+static int rbuVfsShmLock(sqlite3_file *pFile, int ofst, int n, int flags){
+  rbu_file *p = (rbu_file*)pFile;
+  sqlite3rbu *pRbu = p->pRbu;
+  int rc = SQLITE_OK;
+
+#ifdef SQLITE_AMALGAMATION
+    assert( WAL_CKPT_LOCK==1 );
+#endif
+
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
+  if( pRbu && (
+       pRbu->eStage==RBU_STAGE_OAL
+    || pRbu->eStage==RBU_STAGE_MOVE
+    || pRbu->eStage==RBU_STAGE_DONE
+  )){
+    /* Prevent SQLite from taking a shm-lock on the target file when it
+    ** is supplying heap memory to the upper layer in place of *-shm
+    ** segments. */
+    if( ofst==WAL_LOCK_CKPT && n==1 ) rc = SQLITE_BUSY;
+  }else{
+    int bCapture = 0;
+    if( pRbu && pRbu->eStage==RBU_STAGE_CAPTURE ){
+      bCapture = 1;
+    }
+    if( bCapture==0 || 0==(flags & SQLITE_SHM_UNLOCK) ){
+      rc = p->pReal->pMethods->xShmLock(p->pReal, ofst, n, flags);
+      if( bCapture && rc==SQLITE_OK ){
+        pRbu->mLock |= ((1<<n) - 1) << ofst;
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Obtain a pointer to a mapping of a single 32KiB page of the *-shm file.
+*/
+static int rbuVfsShmMap(
+  sqlite3_file *pFile,
+  int iRegion,
+  int szRegion,
+  int isWrite,
+  void volatile **pp
+){
+  rbu_file *p = (rbu_file*)pFile;
+  int rc = SQLITE_OK;
+  int eStage = (p->pRbu ? p->pRbu->eStage : 0);
+
+  /* If not in RBU_STAGE_OAL, allow this call to pass through. Or, if this
+  ** rbu is in the RBU_STAGE_OAL state, use heap memory for *-shm space
+  ** instead of a file on disk.  */
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
+  if( eStage==RBU_STAGE_OAL ){
+    sqlite3_int64 nByte = (iRegion+1) * sizeof(char*);
+    char **apNew = (char**)sqlite3_realloc64(p->apShm, nByte);
+
+    /* This is an RBU connection that uses its own heap memory for the
+    ** pages of the *-shm file. Since no other process can have run
+    ** recovery, the connection must request *-shm pages in order
+    ** from start to finish.  */
+    assert( iRegion==p->nShm );
+    if( apNew==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(&apNew[p->nShm], 0, sizeof(char*) * (1 + iRegion - p->nShm));
+      p->apShm = apNew;
+      p->nShm = iRegion+1;
+    }
+
+    if( rc==SQLITE_OK ){
+      char *pNew = (char*)sqlite3_malloc64(szRegion);
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memset(pNew, 0, szRegion);
+        p->apShm[iRegion] = pNew;
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      *pp = p->apShm[iRegion];
+    }else{
+      *pp = 0;
+    }
+  }else{
+    assert( p->apShm==0 );
+    rc = p->pReal->pMethods->xShmMap(p->pReal, iRegion, szRegion, isWrite, pp);
+  }
+
+  return rc;
+}
+
+/*
+** Memory barrier.
+*/
+static void rbuVfsShmBarrier(sqlite3_file *pFile){
+  rbu_file *p = (rbu_file *)pFile;
+  p->pReal->pMethods->xShmBarrier(p->pReal);
+}
+
+/*
+** The xShmUnmap method.
+*/
+static int rbuVfsShmUnmap(sqlite3_file *pFile, int delFlag){
+  rbu_file *p = (rbu_file*)pFile;
+  int rc = SQLITE_OK;
+  int eStage = (p->pRbu ? p->pRbu->eStage : 0);
+
+  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
+  if( eStage==RBU_STAGE_OAL || eStage==RBU_STAGE_MOVE ){
+    /* no-op */
+  }else{
+    /* Release the checkpointer and writer locks */
+    rbuUnlockShm(p);
+    rc = p->pReal->pMethods->xShmUnmap(p->pReal, delFlag);
+  }
+  return rc;
+}
+
+/*
+** Open an rbu file handle.
+*/
+static int rbuVfsOpen(
+  sqlite3_vfs *pVfs,
+  const char *zName,
+  sqlite3_file *pFile,
+  int flags,
+  int *pOutFlags
+){
+  static sqlite3_io_methods rbuvfs_io_methods = {
+    2,                            /* iVersion */
+    rbuVfsClose,                  /* xClose */
+    rbuVfsRead,                   /* xRead */
+    rbuVfsWrite,                  /* xWrite */
+    rbuVfsTruncate,               /* xTruncate */
+    rbuVfsSync,                   /* xSync */
+    rbuVfsFileSize,               /* xFileSize */
+    rbuVfsLock,                   /* xLock */
+    rbuVfsUnlock,                 /* xUnlock */
+    rbuVfsCheckReservedLock,      /* xCheckReservedLock */
+    rbuVfsFileControl,            /* xFileControl */
+    rbuVfsSectorSize,             /* xSectorSize */
+    rbuVfsDeviceCharacteristics,  /* xDeviceCharacteristics */
+    rbuVfsShmMap,                 /* xShmMap */
+    rbuVfsShmLock,                /* xShmLock */
+    rbuVfsShmBarrier,             /* xShmBarrier */
+    rbuVfsShmUnmap,               /* xShmUnmap */
+    0, 0                          /* xFetch, xUnfetch */
+  };
+  static sqlite3_io_methods rbuvfs_io_methods1 = {
+    1,                            /* iVersion */
+    rbuVfsClose,                  /* xClose */
+    rbuVfsRead,                   /* xRead */
+    rbuVfsWrite,                  /* xWrite */
+    rbuVfsTruncate,               /* xTruncate */
+    rbuVfsSync,                   /* xSync */
+    rbuVfsFileSize,               /* xFileSize */
+    rbuVfsLock,                   /* xLock */
+    rbuVfsUnlock,                 /* xUnlock */
+    rbuVfsCheckReservedLock,      /* xCheckReservedLock */
+    rbuVfsFileControl,            /* xFileControl */
+    rbuVfsSectorSize,             /* xSectorSize */
+    rbuVfsDeviceCharacteristics,  /* xDeviceCharacteristics */
+    0, 0, 0, 0, 0, 0
+  };
+
+
+
+  rbu_vfs *pRbuVfs = (rbu_vfs*)pVfs;
+  sqlite3_vfs *pRealVfs = pRbuVfs->pRealVfs;
+  rbu_file *pFd = (rbu_file *)pFile;
+  int rc = SQLITE_OK;
+  const char *zOpen = zName;
+  int oflags = flags;
+
+  memset(pFd, 0, sizeof(rbu_file));
+  pFd->pReal = (sqlite3_file*)&pFd[1];
+  pFd->pRbuVfs = pRbuVfs;
+  pFd->openFlags = flags;
+  if( zName ){
+    if( flags & SQLITE_OPEN_MAIN_DB ){
+      /* A main database has just been opened. The following block sets
+      ** (pFd->zWal) to point to a buffer owned by SQLite that contains
+      ** the name of the *-wal file this db connection will use. SQLite
+      ** happens to pass a pointer to this buffer when using xAccess()
+      ** or xOpen() to operate on the *-wal file.  */
+      pFd->zWal = sqlite3_filename_wal(zName);
+    }
+    else if( flags & SQLITE_OPEN_WAL ){
+      rbu_file *pDb = rbuFindMaindb(pRbuVfs, zName, 0);
+      if( pDb ){
+        if( pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
+          /* This call is to open a *-wal file. Intead, open the *-oal. */
+          size_t nOpen;
+          if( rbuIsVacuum(pDb->pRbu) ){
+            zOpen = sqlite3_db_filename(pDb->pRbu->dbRbu, "main");
+            zOpen = sqlite3_filename_wal(zOpen);
+          }
+          nOpen = strlen(zOpen);
+          ((char*)zOpen)[nOpen-3] = 'o';
+          pFd->pRbu = pDb->pRbu;
+        }
+        pDb->pWalFd = pFd;
+      }
+    }
+  }else{
+    pFd->pRbu = pRbuVfs->pRbu;
+  }
+
+  if( oflags & SQLITE_OPEN_MAIN_DB
+   && sqlite3_uri_boolean(zName, "rbu_memory", 0)
+  ){
+    assert( oflags & SQLITE_OPEN_MAIN_DB );
+    oflags =  SQLITE_OPEN_TEMP_DB | SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
+              SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE;
+    zOpen = 0;
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = pRealVfs->xOpen(pRealVfs, zOpen, pFd->pReal, oflags, pOutFlags);
+  }
+  if( pFd->pReal->pMethods ){
+    const sqlite3_io_methods *pMeth = pFd->pReal->pMethods;
+    /* The xOpen() operation has succeeded. Set the sqlite3_file.pMethods
+    ** pointer and, if the file is a main database file, link it into the
+    ** mutex protected linked list of all such files.  */
+    if( pMeth->iVersion<2 || pMeth->xShmLock==0 ){
+      pFile->pMethods = &rbuvfs_io_methods1;
+    }else{
+      pFile->pMethods = &rbuvfs_io_methods;
+    }
+    if( flags & SQLITE_OPEN_MAIN_DB ){
+      rbuMainlistAdd(pFd);
+    }
+  }else{
+    sqlite3_free(pFd->zDel);
+  }
+
+  return rc;
+}
+
+/*
+** Delete the file located at zPath.
+*/
+static int rbuVfsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xDelete(pRealVfs, zPath, dirSync);
+}
+
+/*
+** Test for access permissions. Return true if the requested permission
+** is available, or false otherwise.
+*/
+static int rbuVfsAccess(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int flags,
+  int *pResOut
+){
+  rbu_vfs *pRbuVfs = (rbu_vfs*)pVfs;
+  sqlite3_vfs *pRealVfs = pRbuVfs->pRealVfs;
+  int rc;
+
+  rc = pRealVfs->xAccess(pRealVfs, zPath, flags, pResOut);
+
+  /* If this call is to check if a *-wal file associated with an RBU target
+  ** database connection exists, and the RBU update is in RBU_STAGE_OAL,
+  ** the following special handling is activated:
+  **
+  **   a) if the *-wal file does exist, return SQLITE_CANTOPEN. This
+  **      ensures that the RBU extension never tries to update a database
+  **      in wal mode, even if the first page of the database file has
+  **      been damaged.
+  **
+  **   b) if the *-wal file does not exist, claim that it does anyway,
+  **      causing SQLite to call xOpen() to open it. This call will also
+  **      be intercepted (see the rbuVfsOpen() function) and the *-oal
+  **      file opened instead.
+  */
+  if( rc==SQLITE_OK && flags==SQLITE_ACCESS_EXISTS ){
+    rbu_file *pDb = rbuFindMaindb(pRbuVfs, zPath, 1);
+    if( pDb && pDb->pRbu->eStage==RBU_STAGE_OAL ){
+      assert( pDb->pRbu );
+      if( *pResOut ){
+        rc = SQLITE_CANTOPEN;
+      }else{
+        sqlite3_int64 sz = 0;
+        rc = rbuVfsFileSize(&pDb->base, &sz);
+        *pResOut = (sz>0);
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Populate buffer zOut with the full canonical pathname corresponding
+** to the pathname in zPath. zOut is guaranteed to point to a buffer
+** of at least (DEVSYM_MAX_PATHNAME+1) bytes.
+*/
+static int rbuVfsFullPathname(
+  sqlite3_vfs *pVfs,
+  const char *zPath,
+  int nOut,
+  char *zOut
+){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xFullPathname(pRealVfs, zPath, nOut, zOut);
+}
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+/*
+** Open the dynamic library located at zPath and return a handle.
+*/
+static void *rbuVfsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xDlOpen(pRealVfs, zPath);
+}
+
+/*
+** Populate the buffer zErrMsg (size nByte bytes) with a human readable
+** utf-8 string describing the most recent error encountered associated
+** with dynamic libraries.
+*/
+static void rbuVfsDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  pRealVfs->xDlError(pRealVfs, nByte, zErrMsg);
+}
+
+/*
+** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
+*/
+static void (*rbuVfsDlSym(
+  sqlite3_vfs *pVfs,
+  void *pArg,
+  const char *zSym
+))(void){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xDlSym(pRealVfs, pArg, zSym);
+}
+
+/*
+** Close the dynamic library handle pHandle.
+*/
+static void rbuVfsDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  pRealVfs->xDlClose(pRealVfs, pHandle);
+}
+#endif /* SQLITE_OMIT_LOAD_EXTENSION */
+
+/*
+** Populate the buffer pointed to by zBufOut with nByte bytes of
+** random data.
+*/
+static int rbuVfsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xRandomness(pRealVfs, nByte, zBufOut);
+}
+
+/*
+** Sleep for nMicro microseconds. Return the number of microseconds
+** actually slept.
+*/
+static int rbuVfsSleep(sqlite3_vfs *pVfs, int nMicro){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xSleep(pRealVfs, nMicro);
+}
+
+/*
+** Return the current time as a Julian Day number in *pTimeOut.
+*/
+static int rbuVfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+  sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
+  return pRealVfs->xCurrentTime(pRealVfs, pTimeOut);
+}
+
+/*
+** No-op.
+*/
+static int rbuVfsGetLastError(sqlite3_vfs *pVfs, int a, char *b){
+  UNUSED_PARAMETER(pVfs);
+  UNUSED_PARAMETER(a);
+  UNUSED_PARAMETER(b);
+  return 0;
+}
+
+/*
+** Deregister and destroy an RBU vfs created by an earlier call to
+** sqlite3rbu_create_vfs().
+*/
+SQLITE_API void sqlite3rbu_destroy_vfs(const char *zName){
+  sqlite3_vfs *pVfs = sqlite3_vfs_find(zName);
+  if( pVfs && pVfs->xOpen==rbuVfsOpen ){
+    sqlite3_mutex_free(((rbu_vfs*)pVfs)->mutex);
+    sqlite3_vfs_unregister(pVfs);
+    sqlite3_free(pVfs);
+  }
+}
+
+/*
+** Create an RBU VFS named zName that accesses the underlying file-system
+** via existing VFS zParent. The new object is registered as a non-default
+** VFS with SQLite before returning.
+*/
+SQLITE_API int sqlite3rbu_create_vfs(const char *zName, const char *zParent){
+
+  /* Template for VFS */
+  static sqlite3_vfs vfs_template = {
+    1,                            /* iVersion */
+    0,                            /* szOsFile */
+    0,                            /* mxPathname */
+    0,                            /* pNext */
+    0,                            /* zName */
+    0,                            /* pAppData */
+    rbuVfsOpen,                   /* xOpen */
+    rbuVfsDelete,                 /* xDelete */
+    rbuVfsAccess,                 /* xAccess */
+    rbuVfsFullPathname,           /* xFullPathname */
+
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+    rbuVfsDlOpen,                 /* xDlOpen */
+    rbuVfsDlError,                /* xDlError */
+    rbuVfsDlSym,                  /* xDlSym */
+    rbuVfsDlClose,                /* xDlClose */
+#else
+    0, 0, 0, 0,
+#endif
+
+    rbuVfsRandomness,             /* xRandomness */
+    rbuVfsSleep,                  /* xSleep */
+    rbuVfsCurrentTime,            /* xCurrentTime */
+    rbuVfsGetLastError,           /* xGetLastError */
+    0,                            /* xCurrentTimeInt64 (version 2) */
+    0, 0, 0                       /* Unimplemented version 3 methods */
+  };
+
+  rbu_vfs *pNew = 0;              /* Newly allocated VFS */
+  int rc = SQLITE_OK;
+  size_t nName;
+  size_t nByte;
+
+  nName = strlen(zName);
+  nByte = sizeof(rbu_vfs) + nName + 1;
+  pNew = (rbu_vfs*)sqlite3_malloc64(nByte);
+  if( pNew==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_vfs *pParent;           /* Parent VFS */
+    memset(pNew, 0, nByte);
+    pParent = sqlite3_vfs_find(zParent);
+    if( pParent==0 ){
+      rc = SQLITE_NOTFOUND;
+    }else{
+      char *zSpace;
+      memcpy(&pNew->base, &vfs_template, sizeof(sqlite3_vfs));
+      pNew->base.mxPathname = pParent->mxPathname;
+      pNew->base.szOsFile = sizeof(rbu_file) + pParent->szOsFile;
+      pNew->pRealVfs = pParent;
+      pNew->base.zName = (const char*)(zSpace = (char*)&pNew[1]);
+      memcpy(zSpace, zName, nName);
+
+      /* Allocate the mutex and register the new VFS (not as the default) */
+      pNew->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_RECURSIVE);
+      if( pNew->mutex==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        rc = sqlite3_vfs_register(&pNew->base, 0);
+      }
+    }
+
+    if( rc!=SQLITE_OK ){
+      sqlite3_mutex_free(pNew->mutex);
+      sqlite3_free(pNew);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Configure the aggregate temp file size limit for this RBU handle.
+*/
+SQLITE_API sqlite3_int64 sqlite3rbu_temp_size_limit(sqlite3rbu *pRbu, sqlite3_int64 n){
+  if( n>=0 ){
+    pRbu->szTempLimit = n;
+  }
+  return pRbu->szTempLimit;
+}
+
+SQLITE_API sqlite3_int64 sqlite3rbu_temp_size(sqlite3rbu *pRbu){
+  return pRbu->szTemp;
+}
+
+
+/**************************************************************************/
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_RBU) */
+
+/************** End of sqlite3rbu.c ******************************************/
+/************** Begin file dbstat.c ******************************************/
+/*
+** 2010 July 12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains an implementation of the "dbstat" virtual table.
+**
+** The dbstat virtual table is used to extract low-level storage
+** information from an SQLite database in order to implement the
+** "sqlite3_analyzer" utility.  See the ../tool/spaceanal.tcl script
+** for an example implementation.
+**
+** Additional information is available on the "dbstat.html" page of the
+** official SQLite documentation.
+*/
+
+/* #include "sqliteInt.h"   ** Requires access to internal data structures ** */
+#if (defined(SQLITE_ENABLE_DBSTAT_VTAB) || defined(SQLITE_TEST)) \
+    && !defined(SQLITE_OMIT_VIRTUALTABLE)
+
+/*
+** The pager and btree modules arrange objects in memory so that there are
+** always approximately 200 bytes of addressable memory following each page
+** buffer. This way small buffer overreads caused by corrupt database pages
+** do not cause undefined behaviour. This module pads each page buffer
+** by the following number of bytes for the same purpose.
+*/
+#define DBSTAT_PAGE_PADDING_BYTES 256
+
+/*
+** Page paths:
+**
+**   The value of the 'path' column describes the path taken from the
+**   root-node of the b-tree structure to each page. The value of the
+**   root-node path is '/'.
+**
+**   The value of the path for the left-most child page of the root of
+**   a b-tree is '/000/'. (Btrees store content ordered from left to right
+**   so the pages to the left have smaller keys than the pages to the right.)
+**   The next to left-most child of the root page is
+**   '/001', and so on, each sibling page identified by a 3-digit hex
+**   value. The children of the 451st left-most sibling have paths such
+**   as '/1c2/000/, '/1c2/001/' etc.
+**
+**   Overflow pages are specified by appending a '+' character and a
+**   six-digit hexadecimal value to the path to the cell they are linked
+**   from. For example, the three overflow pages in a chain linked from
+**   the left-most cell of the 450th child of the root page are identified
+**   by the paths:
+**
+**      '/1c2/000+000000'         // First page in overflow chain
+**      '/1c2/000+000001'         // Second page in overflow chain
+**      '/1c2/000+000002'         // Third page in overflow chain
+**
+**   If the paths are sorted using the BINARY collation sequence, then
+**   the overflow pages associated with a cell will appear earlier in the
+**   sort-order than its child page:
+**
+**      '/1c2/000/'               // Left-most child of 451st child of root
+*/
+static const char zDbstatSchema[] =
+  "CREATE TABLE x("
+  " name       TEXT,"          /*  0 Name of table or index */
+  " path       TEXT,"          /*  1 Path to page from root (NULL for agg) */
+  " pageno     INTEGER,"       /*  2 Page number (page count for aggregates) */
+  " pagetype   TEXT,"          /*  3 'internal', 'leaf', 'overflow', or NULL */
+  " ncell      INTEGER,"       /*  4 Cells on page (0 for overflow) */
+  " payload    INTEGER,"       /*  5 Bytes of payload on this page */
+  " unused     INTEGER,"       /*  6 Bytes of unused space on this page */
+  " mx_payload INTEGER,"       /*  7 Largest payload size of all cells */
+  " pgoffset   INTEGER,"       /*  8 Offset of page in file (NULL for agg) */
+  " pgsize     INTEGER,"       /*  9 Size of the page (sum for aggregate) */
+  " schema     TEXT HIDDEN,"   /* 10 Database schema being analyzed */
+  " aggregate  BOOLEAN HIDDEN" /* 11 aggregate info for each table */
+  ")"
+;
+
+/* Forward reference to data structured used in this module */
+typedef struct StatTable StatTable;
+typedef struct StatCursor StatCursor;
+typedef struct StatPage StatPage;
+typedef struct StatCell StatCell;
+
+/* Size information for a single cell within a btree page */
+struct StatCell {
+  int nLocal;                     /* Bytes of local payload */
+  u32 iChildPg;                   /* Child node (or 0 if this is a leaf) */
+  int nOvfl;                      /* Entries in aOvfl[] */
+  u32 *aOvfl;                     /* Array of overflow page numbers */
+  int nLastOvfl;                  /* Bytes of payload on final overflow page */
+  int iOvfl;                      /* Iterates through aOvfl[] */
+};
+
+/* Size information for a single btree page */
+struct StatPage {
+  u32 iPgno;                      /* Page number */
+  u8 *aPg;                        /* Page buffer from sqlite3_malloc() */
+  int iCell;                      /* Current cell */
+  char *zPath;                    /* Path to this page */
+
+  /* Variables populated by statDecodePage(): */
+  u8 flags;                       /* Copy of flags byte */
+  int nCell;                      /* Number of cells on page */
+  int nUnused;                    /* Number of unused bytes on page */
+  StatCell *aCell;                /* Array of parsed cells */
+  u32 iRightChildPg;              /* Right-child page number (or 0) */
+  int nMxPayload;                 /* Largest payload of any cell on the page */
+};
+
+/* The cursor for scanning the dbstat virtual table */
+struct StatCursor {
+  sqlite3_vtab_cursor base;       /* base class.  MUST BE FIRST! */
+  sqlite3_stmt *pStmt;            /* Iterates through set of root pages */
+  u8 isEof;                       /* After pStmt has returned SQLITE_DONE */
+  u8 isAgg;                       /* Aggregate results for each table */
+  int iDb;                        /* Schema used for this query */
+
+  StatPage aPage[32];             /* Pages in path to current page */
+  int iPage;                      /* Current entry in aPage[] */
+
+  /* Values to return. */
+  u32 iPageno;                    /* Value of 'pageno' column */
+  char *zName;                    /* Value of 'name' column */
+  char *zPath;                    /* Value of 'path' column */
+  char *zPagetype;                /* Value of 'pagetype' column */
+  int nPage;                      /* Number of pages in current btree */
+  int nCell;                      /* Value of 'ncell' column */
+  int nMxPayload;                 /* Value of 'mx_payload' column */
+  i64 nUnused;                    /* Value of 'unused' column */
+  i64 nPayload;                   /* Value of 'payload' column */
+  i64 iOffset;                    /* Value of 'pgOffset' column */
+  i64 szPage;                     /* Value of 'pgSize' column */
+};
+
+/* An instance of the DBSTAT virtual table */
+struct StatTable {
+  sqlite3_vtab base;              /* base class.  MUST BE FIRST! */
+  sqlite3 *db;                    /* Database connection that owns this vtab */
+  int iDb;                        /* Index of database to analyze */
+};
+
+#ifndef get2byte
+# define get2byte(x)   ((x)[0]<<8 | (x)[1])
+#endif
+
+/*
+** Connect to or create a new DBSTAT virtual table.
+*/
+static int statConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  StatTable *pTab = 0;
+  int rc = SQLITE_OK;
+  int iDb;
+  (void)pAux;
+
+  if( argc>=4 ){
+    Token nm;
+    sqlite3TokenInit(&nm, (char*)argv[3]);
+    iDb = sqlite3FindDb(db, &nm);
+    if( iDb<0 ){
+      *pzErr = sqlite3_mprintf("no such database: %s", argv[3]);
+      return SQLITE_ERROR;
+    }
+  }else{
+    iDb = 0;
+  }
+  sqlite3_vtab_config(db, SQLITE_VTAB_DIRECTONLY);
+  rc = sqlite3_declare_vtab(db, zDbstatSchema);
+  if( rc==SQLITE_OK ){
+    pTab = (StatTable *)sqlite3_malloc64(sizeof(StatTable));
+    if( pTab==0 ) rc = SQLITE_NOMEM_BKPT;
+  }
+
+  assert( rc==SQLITE_OK || pTab==0 );
+  if( rc==SQLITE_OK ){
+    memset(pTab, 0, sizeof(StatTable));
+    pTab->db = db;
+    pTab->iDb = iDb;
+  }
+
+  *ppVtab = (sqlite3_vtab*)pTab;
+  return rc;
+}
+
+/*
+** Disconnect from or destroy the DBSTAT virtual table.
+*/
+static int statDisconnect(sqlite3_vtab *pVtab){
+  sqlite3_free(pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** Compute the best query strategy and return the result in idxNum.
+**
+**   idxNum-Bit        Meaning
+**   ----------        ----------------------------------------------
+**      0x01           There is a schema=? term in the WHERE clause
+**      0x02           There is a name=? term in the WHERE clause
+**      0x04           There is an aggregate=? term in the WHERE clause
+**      0x08           Output should be ordered by name and path
+*/
+static int statBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  int i;
+  int iSchema = -1;
+  int iName = -1;
+  int iAgg = -1;
+  (void)tab;
+
+  /* Look for a valid schema=? constraint.  If found, change the idxNum to
+  ** 1 and request the value of that constraint be sent to xFilter.  And
+  ** lower the cost estimate to encourage the constrained version to be
+  ** used.
+  */
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    if( pIdxInfo->aConstraint[i].op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
+    if( pIdxInfo->aConstraint[i].usable==0 ){
+      /* Force DBSTAT table should always be the right-most table in a join */
+      return SQLITE_CONSTRAINT;
+    }
+    switch( pIdxInfo->aConstraint[i].iColumn ){
+      case 0: {    /* name */
+        iName = i;
+        break;
+      }
+      case 10: {   /* schema */
+        iSchema = i;
+        break;
+      }
+      case 11: {   /* aggregate */
+        iAgg = i;
+        break;
+      }
+    }
+  }
+  i = 0;
+  if( iSchema>=0 ){
+    pIdxInfo->aConstraintUsage[iSchema].argvIndex = ++i;
+    pIdxInfo->aConstraintUsage[iSchema].omit = 1;
+    pIdxInfo->idxNum |= 0x01;
+  }
+  if( iName>=0 ){
+    pIdxInfo->aConstraintUsage[iName].argvIndex = ++i;
+    pIdxInfo->idxNum |= 0x02;
+  }
+  if( iAgg>=0 ){
+    pIdxInfo->aConstraintUsage[iAgg].argvIndex = ++i;
+    pIdxInfo->idxNum |= 0x04;
+  }
+  pIdxInfo->estimatedCost = 1.0;
+
+  /* Records are always returned in ascending order of (name, path).
+  ** If this will satisfy the client, set the orderByConsumed flag so that
+  ** SQLite does not do an external sort.
+  */
+  if( ( pIdxInfo->nOrderBy==1
+     && pIdxInfo->aOrderBy[0].iColumn==0
+     && pIdxInfo->aOrderBy[0].desc==0
+     ) ||
+      ( pIdxInfo->nOrderBy==2
+     && pIdxInfo->aOrderBy[0].iColumn==0
+     && pIdxInfo->aOrderBy[0].desc==0
+     && pIdxInfo->aOrderBy[1].iColumn==1
+     && pIdxInfo->aOrderBy[1].desc==0
+     )
+  ){
+    pIdxInfo->orderByConsumed = 1;
+    pIdxInfo->idxNum |= 0x08;
+  }
+  pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_HEX;
+
+  return SQLITE_OK;
+}
+
+/*
+** Open a new DBSTAT cursor.
+*/
+static int statOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+  StatTable *pTab = (StatTable *)pVTab;
+  StatCursor *pCsr;
+
+  pCsr = (StatCursor *)sqlite3_malloc64(sizeof(StatCursor));
+  if( pCsr==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }else{
+    memset(pCsr, 0, sizeof(StatCursor));
+    pCsr->base.pVtab = pVTab;
+    pCsr->iDb = pTab->iDb;
+  }
+
+  *ppCursor = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+static void statClearCells(StatPage *p){
+  int i;
+  if( p->aCell ){
+    for(i=0; i<p->nCell; i++){
+      sqlite3_free(p->aCell[i].aOvfl);
+    }
+    sqlite3_free(p->aCell);
+  }
+  p->nCell = 0;
+  p->aCell = 0;
+}
+
+static void statClearPage(StatPage *p){
+  u8 *aPg = p->aPg;
+  statClearCells(p);
+  sqlite3_free(p->zPath);
+  memset(p, 0, sizeof(StatPage));
+  p->aPg = aPg;
+}
+
+static void statResetCsr(StatCursor *pCsr){
+  int i;
+  /* In some circumstances, specifically if an OOM has occurred, the call
+  ** to sqlite3_reset() may cause the pager to be reset (emptied). It is
+  ** important that statClearPage() is called to free any page refs before
+  ** this happens. dbsqlfuzz 9ed3e4e3816219d3509d711636c38542bf3f40b1. */
+  for(i=0; i<ArraySize(pCsr->aPage); i++){
+    statClearPage(&pCsr->aPage[i]);
+    sqlite3_free(pCsr->aPage[i].aPg);
+    pCsr->aPage[i].aPg = 0;
+  }
+  sqlite3_reset(pCsr->pStmt);
+  pCsr->iPage = 0;
+  sqlite3_free(pCsr->zPath);
+  pCsr->zPath = 0;
+  pCsr->isEof = 0;
+}
+
+/* Resize the space-used counters inside of the cursor */
+static void statResetCounts(StatCursor *pCsr){
+  pCsr->nCell = 0;
+  pCsr->nMxPayload = 0;
+  pCsr->nUnused = 0;
+  pCsr->nPayload = 0;
+  pCsr->szPage = 0;
+  pCsr->nPage = 0;
+}
+
+/*
+** Close a DBSTAT cursor.
+*/
+static int statClose(sqlite3_vtab_cursor *pCursor){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  statResetCsr(pCsr);
+  sqlite3_finalize(pCsr->pStmt);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** For a single cell on a btree page, compute the number of bytes of
+** content (payload) stored on that page.  That is to say, compute the
+** number of bytes of content not found on overflow pages.
+*/
+static int getLocalPayload(
+  int nUsable,                    /* Usable bytes per page */
+  u8 flags,                       /* Page flags */
+  int nTotal                      /* Total record (payload) size */
+){
+  int nLocal;
+  int nMinLocal;
+  int nMaxLocal;
+
+  if( flags==0x0D ){              /* Table leaf node */
+    nMinLocal = (nUsable - 12) * 32 / 255 - 23;
+    nMaxLocal = nUsable - 35;
+  }else{                          /* Index interior and leaf nodes */
+    nMinLocal = (nUsable - 12) * 32 / 255 - 23;
+    nMaxLocal = (nUsable - 12) * 64 / 255 - 23;
+  }
+
+  nLocal = nMinLocal + (nTotal - nMinLocal) % (nUsable - 4);
+  if( nLocal>nMaxLocal ) nLocal = nMinLocal;
+  return nLocal;
+}
+
+/* Populate the StatPage object with information about the all
+** cells found on the page currently under analysis.
+*/
+static int statDecodePage(Btree *pBt, StatPage *p){
+  int nUnused;
+  int iOff;
+  int nHdr;
+  int isLeaf;
+  int szPage;
+
+  u8 *aData = p->aPg;
+  u8 *aHdr = &aData[p->iPgno==1 ? 100 : 0];
+
+  p->flags = aHdr[0];
+  if( p->flags==0x0A || p->flags==0x0D ){
+    isLeaf = 1;
+    nHdr = 8;
+  }else if( p->flags==0x05 || p->flags==0x02 ){
+    isLeaf = 0;
+    nHdr = 12;
+  }else{
+    goto statPageIsCorrupt;
+  }
+  if( p->iPgno==1 ) nHdr += 100;
+  p->nCell = get2byte(&aHdr[3]);
+  p->nMxPayload = 0;
+  szPage = sqlite3BtreeGetPageSize(pBt);
+
+  nUnused = get2byte(&aHdr[5]) - nHdr - 2*p->nCell;
+  nUnused += (int)aHdr[7];
+  iOff = get2byte(&aHdr[1]);
+  while( iOff ){
+    int iNext;
+    if( iOff>=szPage ) goto statPageIsCorrupt;
+    nUnused += get2byte(&aData[iOff+2]);
+    iNext = get2byte(&aData[iOff]);
+    if( iNext<iOff+4 && iNext>0 ) goto statPageIsCorrupt;
+    iOff = iNext;
+  }
+  p->nUnused = nUnused;
+  p->iRightChildPg = isLeaf ? 0 : sqlite3Get4byte(&aHdr[8]);
+
+  if( p->nCell ){
+    int i;                        /* Used to iterate through cells */
+    int nUsable;                  /* Usable bytes per page */
+
+    sqlite3BtreeEnter(pBt);
+    nUsable = szPage - sqlite3BtreeGetReserveNoMutex(pBt);
+    sqlite3BtreeLeave(pBt);
+    p->aCell = sqlite3_malloc64((p->nCell+1) * sizeof(StatCell));
+    if( p->aCell==0 ) return SQLITE_NOMEM_BKPT;
+    memset(p->aCell, 0, (p->nCell+1) * sizeof(StatCell));
+
+    for(i=0; i<p->nCell; i++){
+      StatCell *pCell = &p->aCell[i];
+
+      iOff = get2byte(&aData[nHdr+i*2]);
+      if( iOff<nHdr || iOff>=szPage ) goto statPageIsCorrupt;
+      if( !isLeaf ){
+        pCell->iChildPg = sqlite3Get4byte(&aData[iOff]);
+        iOff += 4;
+      }
+      if( p->flags==0x05 ){
+        /* A table interior node. nPayload==0. */
+      }else{
+        u32 nPayload;             /* Bytes of payload total (local+overflow) */
+        int nLocal;               /* Bytes of payload stored locally */
+        iOff += getVarint32(&aData[iOff], nPayload);
+        if( p->flags==0x0D ){
+          u64 dummy;
+          iOff += sqlite3GetVarint(&aData[iOff], &dummy);
+        }
+        if( nPayload>(u32)p->nMxPayload ) p->nMxPayload = nPayload;
+        nLocal = getLocalPayload(nUsable, p->flags, nPayload);
+        if( nLocal<0 ) goto statPageIsCorrupt;
+        pCell->nLocal = nLocal;
+        assert( nPayload>=(u32)nLocal );
+        assert( nLocal<=(nUsable-35) );
+        if( nPayload>(u32)nLocal ){
+          int j;
+          int nOvfl = ((nPayload - nLocal) + nUsable-4 - 1) / (nUsable - 4);
+          if( iOff+nLocal+4>nUsable || nPayload>0x7fffffff ){
+            goto statPageIsCorrupt;
+          }
+          pCell->nLastOvfl = (nPayload-nLocal) - (nOvfl-1) * (nUsable-4);
+          pCell->nOvfl = nOvfl;
+          pCell->aOvfl = sqlite3_malloc64(sizeof(u32)*nOvfl);
+          if( pCell->aOvfl==0 ) return SQLITE_NOMEM_BKPT;
+          pCell->aOvfl[0] = sqlite3Get4byte(&aData[iOff+nLocal]);
+          for(j=1; j<nOvfl; j++){
+            int rc;
+            u32 iPrev = pCell->aOvfl[j-1];
+            DbPage *pPg = 0;
+            rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPrev, &pPg, 0);
+            if( rc!=SQLITE_OK ){
+              assert( pPg==0 );
+              return rc;
+            }
+            pCell->aOvfl[j] = sqlite3Get4byte(sqlite3PagerGetData(pPg));
+            sqlite3PagerUnref(pPg);
+          }
+        }
+      }
+    }
+  }
+
+  return SQLITE_OK;
+
+statPageIsCorrupt:
+  p->flags = 0;
+  statClearCells(p);
+  return SQLITE_OK;
+}
+
+/*
+** Populate the pCsr->iOffset and pCsr->szPage member variables. Based on
+** the current value of pCsr->iPageno.
+*/
+static void statSizeAndOffset(StatCursor *pCsr){
+  StatTable *pTab = (StatTable *)((sqlite3_vtab_cursor *)pCsr)->pVtab;
+  Btree *pBt = pTab->db->aDb[pTab->iDb].pBt;
+  Pager *pPager = sqlite3BtreePager(pBt);
+  sqlite3_file *fd;
+  sqlite3_int64 x[2];
+
+  /* If connected to a ZIPVFS backend, find the page size and
+  ** offset from ZIPVFS.
+  */
+  fd = sqlite3PagerFile(pPager);
+  x[0] = pCsr->iPageno;
+  if( sqlite3OsFileControl(fd, 230440, &x)==SQLITE_OK ){
+    pCsr->iOffset = x[0];
+    pCsr->szPage += x[1];
+  }else{
+    /* Not ZIPVFS: The default page size and offset */
+    pCsr->szPage += sqlite3BtreeGetPageSize(pBt);
+    pCsr->iOffset = (i64)pCsr->szPage * (pCsr->iPageno - 1);
+  }
+}
+
+/*
+** Load a copy of the page data for page iPg into the buffer belonging
+** to page object pPg. Allocate the buffer if necessary. Return SQLITE_OK
+** if successful, or an SQLite error code otherwise.
+*/
+static int statGetPage(
+  Btree *pBt,                     /* Load page from this b-tree */
+  u32 iPg,                        /* Page number to load */
+  StatPage *pPg                   /* Load page into this object */
+){
+  int pgsz = sqlite3BtreeGetPageSize(pBt);
+  DbPage *pDbPage = 0;
+  int rc;
+
+  if( pPg->aPg==0 ){
+    pPg->aPg = (u8*)sqlite3_malloc(pgsz + DBSTAT_PAGE_PADDING_BYTES);
+    if( pPg->aPg==0 ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    memset(&pPg->aPg[pgsz], 0, DBSTAT_PAGE_PADDING_BYTES);
+  }
+
+  rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPg, &pDbPage, 0);
+  if( rc==SQLITE_OK ){
+    const u8 *a = sqlite3PagerGetData(pDbPage);
+    memcpy(pPg->aPg, a, pgsz);
+    sqlite3PagerUnref(pDbPage);
+  }
+
+  return rc;
+}
+
+/*
+** Move a DBSTAT cursor to the next entry.  Normally, the next
+** entry will be the next page, but in aggregated mode (pCsr->isAgg!=0),
+** the next entry is the next btree.
+*/
+static int statNext(sqlite3_vtab_cursor *pCursor){
+  int rc;
+  int nPayload;
+  char *z;
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  StatTable *pTab = (StatTable *)pCursor->pVtab;
+  Btree *pBt = pTab->db->aDb[pCsr->iDb].pBt;
+  Pager *pPager = sqlite3BtreePager(pBt);
+
+  sqlite3_free(pCsr->zPath);
+  pCsr->zPath = 0;
+
+statNextRestart:
+  if( pCsr->iPage<0 ){
+    /* Start measuring space on the next btree */
+    statResetCounts(pCsr);
+    rc = sqlite3_step(pCsr->pStmt);
+    if( rc==SQLITE_ROW ){
+      int nPage;
+      u32 iRoot = (u32)sqlite3_column_int64(pCsr->pStmt, 1);
+      sqlite3PagerPagecount(pPager, &nPage);
+      if( nPage==0 ){
+        pCsr->isEof = 1;
+        return sqlite3_reset(pCsr->pStmt);
+      }
+      rc = statGetPage(pBt, iRoot, &pCsr->aPage[0]);
+      pCsr->aPage[0].iPgno = iRoot;
+      pCsr->aPage[0].iCell = 0;
+      if( !pCsr->isAgg ){
+        pCsr->aPage[0].zPath = z = sqlite3_mprintf("/");
+        if( z==0 ) rc = SQLITE_NOMEM_BKPT;
+      }
+      pCsr->iPage = 0;
+      pCsr->nPage = 1;
+    }else{
+      pCsr->isEof = 1;
+      return sqlite3_reset(pCsr->pStmt);
+    }
+  }else{
+    /* Continue analyzing the btree previously started */
+    StatPage *p = &pCsr->aPage[pCsr->iPage];
+    if( !pCsr->isAgg ) statResetCounts(pCsr);
+    while( p->iCell<p->nCell ){
+      StatCell *pCell = &p->aCell[p->iCell];
+      while( pCell->iOvfl<pCell->nOvfl ){
+        int nUsable, iOvfl;
+        sqlite3BtreeEnter(pBt);
+        nUsable = sqlite3BtreeGetPageSize(pBt) -
+                        sqlite3BtreeGetReserveNoMutex(pBt);
+        sqlite3BtreeLeave(pBt);
+        pCsr->nPage++;
+        statSizeAndOffset(pCsr);
+        if( pCell->iOvfl<pCell->nOvfl-1 ){
+          pCsr->nPayload += nUsable - 4;
+        }else{
+          pCsr->nPayload += pCell->nLastOvfl;
+          pCsr->nUnused += nUsable - 4 - pCell->nLastOvfl;
+        }
+        iOvfl = pCell->iOvfl;
+        pCell->iOvfl++;
+        if( !pCsr->isAgg ){
+          pCsr->zName = (char *)sqlite3_column_text(pCsr->pStmt, 0);
+          pCsr->iPageno = pCell->aOvfl[iOvfl];
+          pCsr->zPagetype = "overflow";
+          pCsr->zPath = z = sqlite3_mprintf(
+              "%s%.3x+%.6x", p->zPath, p->iCell, iOvfl
+          );
+          return z==0 ? SQLITE_NOMEM_BKPT : SQLITE_OK;
+        }
+      }
+      if( p->iRightChildPg ) break;
+      p->iCell++;
+    }
+
+    if( !p->iRightChildPg || p->iCell>p->nCell ){
+      statClearPage(p);
+      pCsr->iPage--;
+      if( pCsr->isAgg && pCsr->iPage<0 ){
+        /* label-statNext-done:  When computing aggregate space usage over
+        ** an entire btree, this is the exit point from this function */
+        return SQLITE_OK;
+      }
+      goto statNextRestart; /* Tail recursion */
+    }
+    pCsr->iPage++;
+    if( pCsr->iPage>=ArraySize(pCsr->aPage) ){
+      statResetCsr(pCsr);
+      return SQLITE_CORRUPT_BKPT;
+    }
+    assert( p==&pCsr->aPage[pCsr->iPage-1] );
+
+    if( p->iCell==p->nCell ){
+      p[1].iPgno = p->iRightChildPg;
+    }else{
+      p[1].iPgno = p->aCell[p->iCell].iChildPg;
+    }
+    rc = statGetPage(pBt, p[1].iPgno, &p[1]);
+    pCsr->nPage++;
+    p[1].iCell = 0;
+    if( !pCsr->isAgg ){
+      p[1].zPath = z = sqlite3_mprintf("%s%.3x/", p->zPath, p->iCell);
+      if( z==0 ) rc = SQLITE_NOMEM_BKPT;
+    }
+    p->iCell++;
+  }
+
+
+  /* Populate the StatCursor fields with the values to be returned
+  ** by the xColumn() and xRowid() methods.
+  */
+  if( rc==SQLITE_OK ){
+    int i;
+    StatPage *p = &pCsr->aPage[pCsr->iPage];
+    pCsr->zName = (char *)sqlite3_column_text(pCsr->pStmt, 0);
+    pCsr->iPageno = p->iPgno;
+
+    rc = statDecodePage(pBt, p);
+    if( rc==SQLITE_OK ){
+      statSizeAndOffset(pCsr);
+
+      switch( p->flags ){
+        case 0x05:             /* table internal */
+        case 0x02:             /* index internal */
+          pCsr->zPagetype = "internal";
+          break;
+        case 0x0D:             /* table leaf */
+        case 0x0A:             /* index leaf */
+          pCsr->zPagetype = "leaf";
+          break;
+        default:
+          pCsr->zPagetype = "corrupted";
+          break;
+      }
+      pCsr->nCell += p->nCell;
+      pCsr->nUnused += p->nUnused;
+      if( p->nMxPayload>pCsr->nMxPayload ) pCsr->nMxPayload = p->nMxPayload;
+      if( !pCsr->isAgg ){
+        pCsr->zPath = z = sqlite3_mprintf("%s", p->zPath);
+        if( z==0 ) rc = SQLITE_NOMEM_BKPT;
+      }
+      nPayload = 0;
+      for(i=0; i<p->nCell; i++){
+        nPayload += p->aCell[i].nLocal;
+      }
+      pCsr->nPayload += nPayload;
+
+      /* If computing aggregate space usage by btree, continue with the
+      ** next page.  The loop will exit via the return at label-statNext-done
+      */
+      if( pCsr->isAgg ) goto statNextRestart;
+    }
+  }
+
+  return rc;
+}
+
+static int statEof(sqlite3_vtab_cursor *pCursor){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  return pCsr->isEof;
+}
+
+/* Initialize a cursor according to the query plan idxNum using the
+** arguments in argv[0].  See statBestIndex() for a description of the
+** meaning of the bits in idxNum.
+*/
+static int statFilter(
+  sqlite3_vtab_cursor *pCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  StatTable *pTab = (StatTable*)(pCursor->pVtab);
+  sqlite3_str *pSql;      /* Query of btrees to analyze */
+  char *zSql;             /* String value of pSql */
+  int iArg = 0;           /* Count of argv[] parameters used so far */
+  int rc = SQLITE_OK;     /* Result of this operation */
+  const char *zName = 0;  /* Only provide analysis of this table */
+  (void)argc;
+  (void)idxStr;
+
+  statResetCsr(pCsr);
+  sqlite3_finalize(pCsr->pStmt);
+  pCsr->pStmt = 0;
+  if( idxNum & 0x01 ){
+    /* schema=? constraint is present.  Get its value */
+    const char *zDbase = (const char*)sqlite3_value_text(argv[iArg++]);
+    pCsr->iDb = sqlite3FindDbName(pTab->db, zDbase);
+    if( pCsr->iDb<0 ){
+      pCsr->iDb = 0;
+      pCsr->isEof = 1;
+      return SQLITE_OK;
+    }
+  }else{
+    pCsr->iDb = pTab->iDb;
+  }
+  if( idxNum & 0x02 ){
+    /* name=? constraint is present */
+    zName = (const char*)sqlite3_value_text(argv[iArg++]);
+  }
+  if( idxNum & 0x04 ){
+    /* aggregate=? constraint is present */
+    pCsr->isAgg = sqlite3_value_double(argv[iArg++])!=0.0;
+  }else{
+    pCsr->isAgg = 0;
+  }
+  pSql = sqlite3_str_new(pTab->db);
+  sqlite3_str_appendf(pSql,
+      "SELECT * FROM ("
+        "SELECT 'sqlite_schema' AS name,1 AS rootpage,'table' AS type"
+        " UNION ALL "
+        "SELECT name,rootpage,type"
+        " FROM \"%w\".sqlite_schema WHERE rootpage!=0)",
+      pTab->db->aDb[pCsr->iDb].zDbSName);
+  if( zName ){
+    sqlite3_str_appendf(pSql, "WHERE name=%Q", zName);
+  }
+  if( idxNum & 0x08 ){
+    sqlite3_str_appendf(pSql, " ORDER BY name");
+  }
+  zSql = sqlite3_str_finish(pSql);
+  if( zSql==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }else{
+    rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pStmt, 0);
+    sqlite3_free(zSql);
+  }
+
+  if( rc==SQLITE_OK ){
+    pCsr->iPage = -1;
+    rc = statNext(pCursor);
+  }
+  return rc;
+}
+
+static int statColumn(
+  sqlite3_vtab_cursor *pCursor,
+  sqlite3_context *ctx,
+  int i
+){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  switch( i ){
+    case 0:            /* name */
+      sqlite3_result_text(ctx, pCsr->zName, -1, SQLITE_TRANSIENT);
+      break;
+    case 1:            /* path */
+      if( !pCsr->isAgg ){
+        sqlite3_result_text(ctx, pCsr->zPath, -1, SQLITE_TRANSIENT);
+      }
+      break;
+    case 2:            /* pageno */
+      if( pCsr->isAgg ){
+        sqlite3_result_int64(ctx, pCsr->nPage);
+      }else{
+        sqlite3_result_int64(ctx, pCsr->iPageno);
+      }
+      break;
+    case 3:            /* pagetype */
+      if( !pCsr->isAgg ){
+        sqlite3_result_text(ctx, pCsr->zPagetype, -1, SQLITE_STATIC);
+      }
+      break;
+    case 4:            /* ncell */
+      sqlite3_result_int64(ctx, pCsr->nCell);
+      break;
+    case 5:            /* payload */
+      sqlite3_result_int64(ctx, pCsr->nPayload);
+      break;
+    case 6:            /* unused */
+      sqlite3_result_int64(ctx, pCsr->nUnused);
+      break;
+    case 7:            /* mx_payload */
+      sqlite3_result_int64(ctx, pCsr->nMxPayload);
+      break;
+    case 8:            /* pgoffset */
+      if( !pCsr->isAgg ){
+        sqlite3_result_int64(ctx, pCsr->iOffset);
+      }
+      break;
+    case 9:            /* pgsize */
+      sqlite3_result_int64(ctx, pCsr->szPage);
+      break;
+    case 10: {         /* schema */
+      sqlite3 *db = sqlite3_context_db_handle(ctx);
+      int iDb = pCsr->iDb;
+      sqlite3_result_text(ctx, db->aDb[iDb].zDbSName, -1, SQLITE_STATIC);
+      break;
+    }
+    default: {         /* aggregate */
+      sqlite3_result_int(ctx, pCsr->isAgg);
+      break;
+    }
+  }
+  return SQLITE_OK;
+}
+
+static int statRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  StatCursor *pCsr = (StatCursor *)pCursor;
+  *pRowid = pCsr->iPageno;
+  return SQLITE_OK;
+}
+
+/*
+** Invoke this routine to register the "dbstat" virtual table module
+*/
+SQLITE_PRIVATE int sqlite3DbstatRegister(sqlite3 *db){
+  static sqlite3_module dbstat_module = {
+    0,                            /* iVersion */
+    statConnect,                  /* xCreate */
+    statConnect,                  /* xConnect */
+    statBestIndex,                /* xBestIndex */
+    statDisconnect,               /* xDisconnect */
+    statDisconnect,               /* xDestroy */
+    statOpen,                     /* xOpen - open a cursor */
+    statClose,                    /* xClose - close a cursor */
+    statFilter,                   /* xFilter - configure scan constraints */
+    statNext,                     /* xNext - advance a cursor */
+    statEof,                      /* xEof - check for end of scan */
+    statColumn,                   /* xColumn - read data */
+    statRowid,                    /* xRowid - read data */
+    0,                            /* xUpdate */
+    0,                            /* xBegin */
+    0,                            /* xSync */
+    0,                            /* xCommit */
+    0,                            /* xRollback */
+    0,                            /* xFindMethod */
+    0,                            /* xRename */
+    0,                            /* xSavepoint */
+    0,                            /* xRelease */
+    0,                            /* xRollbackTo */
+    0,                            /* xShadowName */
+    0                             /* xIntegrity */
+  };
+  return sqlite3_create_module(db, "dbstat", &dbstat_module, 0);
+}
+#elif defined(SQLITE_ENABLE_DBSTAT_VTAB)
+SQLITE_PRIVATE int sqlite3DbstatRegister(sqlite3 *db){ return SQLITE_OK; }
+#endif /* SQLITE_ENABLE_DBSTAT_VTAB */
+
+/************** End of dbstat.c **********************************************/
+/************** Begin file dbpage.c ******************************************/
+/*
+** 2017-10-11
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains an implementation of the "sqlite_dbpage" virtual table.
+**
+** The sqlite_dbpage virtual table is used to read or write whole raw
+** pages of the database file.  The pager interface is used so that
+** uncommitted changes and changes recorded in the WAL file are correctly
+** retrieved.
+**
+** Usage example:
+**
+**    SELECT data FROM sqlite_dbpage('aux1') WHERE pgno=123;
+**
+** This is an eponymous virtual table so it does not need to be created before
+** use.  The optional argument to the sqlite_dbpage() table name is the
+** schema for the database file that is to be read.  The default schema is
+** "main".
+**
+** The data field of sqlite_dbpage table can be updated.  The new
+** value must be a BLOB which is the correct page size, otherwise the
+** update fails.  INSERT operations also work, and operate as if they
+** where REPLACE.  The size of the database can be extended by INSERT-ing
+** new pages on the end.
+**
+** Rows may not be deleted.  However, doing an INSERT to page number N
+** with NULL page data causes the N-th page and all subsequent pages to be
+** deleted and the database to be truncated.
+*/
+
+/* #include "sqliteInt.h"   ** Requires access to internal data structures ** */
+#if (defined(SQLITE_ENABLE_DBPAGE_VTAB) || defined(SQLITE_TEST)) \
+    && !defined(SQLITE_OMIT_VIRTUALTABLE)
+
+typedef struct DbpageTable DbpageTable;
+typedef struct DbpageCursor DbpageCursor;
+
+struct DbpageCursor {
+  sqlite3_vtab_cursor base;       /* Base class.  Must be first */
+  int pgno;                       /* Current page number */
+  int mxPgno;                     /* Last page to visit on this scan */
+  Pager *pPager;                  /* Pager being read/written */
+  DbPage *pPage1;                 /* Page 1 of the database */
+  int iDb;                        /* Index of database to analyze */
+  int szPage;                     /* Size of each page in bytes */
+};
+
+struct DbpageTable {
+  sqlite3_vtab base;              /* Base class.  Must be first */
+  sqlite3 *db;                    /* The database */
+  int iDbTrunc;                   /* Database to truncate */
+  Pgno pgnoTrunc;                 /* Size to truncate to */
+};
+
+/* Columns */
+#define DBPAGE_COLUMN_PGNO    0
+#define DBPAGE_COLUMN_DATA    1
+#define DBPAGE_COLUMN_SCHEMA  2
+
+
+/*
+** Connect to or create a dbpagevfs virtual table.
+*/
+static int dbpageConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  DbpageTable *pTab = 0;
+  int rc = SQLITE_OK;
+  (void)pAux;
+  (void)argc;
+  (void)argv;
+  (void)pzErr;
+
+  sqlite3_vtab_config(db, SQLITE_VTAB_DIRECTONLY);
+  sqlite3_vtab_config(db, SQLITE_VTAB_USES_ALL_SCHEMAS);
+  rc = sqlite3_declare_vtab(db,
+          "CREATE TABLE x(pgno INTEGER PRIMARY KEY, data BLOB, schema HIDDEN)");
+  if( rc==SQLITE_OK ){
+    pTab = (DbpageTable *)sqlite3_malloc64(sizeof(DbpageTable));
+    if( pTab==0 ) rc = SQLITE_NOMEM_BKPT;
+  }
+
+  assert( rc==SQLITE_OK || pTab==0 );
+  if( rc==SQLITE_OK ){
+    memset(pTab, 0, sizeof(DbpageTable));
+    pTab->db = db;
+  }
+
+  *ppVtab = (sqlite3_vtab*)pTab;
+  return rc;
+}
+
+/*
+** Disconnect from or destroy a dbpagevfs virtual table.
+*/
+static int dbpageDisconnect(sqlite3_vtab *pVtab){
+  sqlite3_free(pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** idxNum:
+**
+**     0     schema=main, full table scan
+**     1     schema=main, pgno=?1
+**     2     schema=?1, full table scan
+**     3     schema=?1, pgno=?2
+*/
+static int dbpageBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  int i;
+  int iPlan = 0;
+  (void)tab;
+
+  /* If there is a schema= constraint, it must be honored.  Report a
+  ** ridiculously large estimated cost if the schema= constraint is
+  ** unavailable
+  */
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[i];
+    if( p->iColumn!=DBPAGE_COLUMN_SCHEMA ) continue;
+    if( p->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
+    if( !p->usable ){
+      /* No solution. */
+      return SQLITE_CONSTRAINT;
+    }
+    iPlan = 2;
+    pIdxInfo->aConstraintUsage[i].argvIndex = 1;
+    pIdxInfo->aConstraintUsage[i].omit = 1;
+    break;
+  }
+
+  /* If we reach this point, it means that either there is no schema=
+  ** constraint (in which case we use the "main" schema) or else the
+  ** schema constraint was accepted.  Lower the estimated cost accordingly
+  */
+  pIdxInfo->estimatedCost = 1.0e6;
+
+  /* Check for constraints against pgno */
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[i];
+    if( p->usable && p->iColumn<=0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ ){
+      pIdxInfo->estimatedRows = 1;
+      pIdxInfo->idxFlags = SQLITE_INDEX_SCAN_UNIQUE;
+      pIdxInfo->estimatedCost = 1.0;
+      pIdxInfo->aConstraintUsage[i].argvIndex = iPlan ? 2 : 1;
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      iPlan |= 1;
+      break;
+    }
+  }
+  pIdxInfo->idxNum = iPlan;
+
+  if( pIdxInfo->nOrderBy>=1
+   && pIdxInfo->aOrderBy[0].iColumn<=0
+   && pIdxInfo->aOrderBy[0].desc==0
+  ){
+    pIdxInfo->orderByConsumed = 1;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Open a new dbpagevfs cursor.
+*/
+static int dbpageOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+  DbpageCursor *pCsr;
+
+  pCsr = (DbpageCursor *)sqlite3_malloc64(sizeof(DbpageCursor));
+  if( pCsr==0 ){
+    return SQLITE_NOMEM_BKPT;
+  }else{
+    memset(pCsr, 0, sizeof(DbpageCursor));
+    pCsr->base.pVtab = pVTab;
+    pCsr->pgno = -1;
+  }
+
+  *ppCursor = (sqlite3_vtab_cursor *)pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** Close a dbpagevfs cursor.
+*/
+static int dbpageClose(sqlite3_vtab_cursor *pCursor){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  if( pCsr->pPage1 ) sqlite3PagerUnrefPageOne(pCsr->pPage1);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** Move a dbpagevfs cursor to the next entry in the file.
+*/
+static int dbpageNext(sqlite3_vtab_cursor *pCursor){
+  int rc = SQLITE_OK;
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  pCsr->pgno++;
+  return rc;
+}
+
+static int dbpageEof(sqlite3_vtab_cursor *pCursor){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  return pCsr->pgno > pCsr->mxPgno;
+}
+
+/*
+** idxNum:
+**
+**     0     schema=main, full table scan
+**     1     schema=main, pgno=?1
+**     2     schema=?1, full table scan
+**     3     schema=?1, pgno=?2
+**
+** idxStr is not used
+*/
+static int dbpageFilter(
+  sqlite3_vtab_cursor *pCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  DbpageTable *pTab = (DbpageTable *)pCursor->pVtab;
+  int rc;
+  sqlite3 *db = pTab->db;
+  Btree *pBt;
+
+  (void)idxStr;
+
+  /* Default setting is no rows of result */
+  pCsr->pgno = 1;
+  pCsr->mxPgno = 0;
+
+  if( idxNum & 2 ){
+    const char *zSchema;
+    assert( argc>=1 );
+    zSchema = (const char*)sqlite3_value_text(argv[0]);
+    pCsr->iDb = sqlite3FindDbName(db, zSchema);
+    if( pCsr->iDb<0 ) return SQLITE_OK;
+  }else{
+    pCsr->iDb = 0;
+  }
+  pBt = db->aDb[pCsr->iDb].pBt;
+  if( NEVER(pBt==0) ) return SQLITE_OK;
+  pCsr->pPager = sqlite3BtreePager(pBt);
+  pCsr->szPage = sqlite3BtreeGetPageSize(pBt);
+  pCsr->mxPgno = sqlite3BtreeLastPage(pBt);
+  if( idxNum & 1 ){
+    assert( argc>(idxNum>>1) );
+    pCsr->pgno = sqlite3_value_int(argv[idxNum>>1]);
+    if( pCsr->pgno<1 || pCsr->pgno>pCsr->mxPgno ){
+      pCsr->pgno = 1;
+      pCsr->mxPgno = 0;
+    }else{
+      pCsr->mxPgno = pCsr->pgno;
+    }
+  }else{
+    assert( pCsr->pgno==1 );
+  }
+  if( pCsr->pPage1 ) sqlite3PagerUnrefPageOne(pCsr->pPage1);
+  rc = sqlite3PagerGet(pCsr->pPager, 1, &pCsr->pPage1, 0);
+  return rc;
+}
+
+static int dbpageColumn(
+  sqlite3_vtab_cursor *pCursor,
+  sqlite3_context *ctx,
+  int i
+){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  int rc = SQLITE_OK;
+  switch( i ){
+    case 0: {           /* pgno */
+      sqlite3_result_int(ctx, pCsr->pgno);
+      break;
+    }
+    case 1: {           /* data */
+      DbPage *pDbPage = 0;
+      if( pCsr->pgno==((PENDING_BYTE/pCsr->szPage)+1) ){
+        /* The pending byte page. Assume it is zeroed out. Attempting to
+        ** request this page from the page is an SQLITE_CORRUPT error. */
+        sqlite3_result_zeroblob(ctx, pCsr->szPage);
+      }else{
+        rc = sqlite3PagerGet(pCsr->pPager, pCsr->pgno, (DbPage**)&pDbPage, 0);
+        if( rc==SQLITE_OK ){
+          sqlite3_result_blob(ctx, sqlite3PagerGetData(pDbPage), pCsr->szPage,
+              SQLITE_TRANSIENT);
+        }
+        sqlite3PagerUnref(pDbPage);
+      }
+      break;
+    }
+    default: {          /* schema */
+      sqlite3 *db = sqlite3_context_db_handle(ctx);
+      sqlite3_result_text(ctx, db->aDb[pCsr->iDb].zDbSName, -1, SQLITE_STATIC);
+      break;
+    }
+  }
+  return rc;
+}
+
+static int dbpageRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
+  *pRowid = pCsr->pgno;
+  return SQLITE_OK;
+}
+
+/*
+** Open write transactions. Since we do not know in advance which database
+** files will be written by the sqlite_dbpage virtual table, start a write
+** transaction on them all.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise.
+*/
+static int dbpageBeginTrans(DbpageTable *pTab){
+  sqlite3 *db = pTab->db;
+  int rc = SQLITE_OK;
+  int i;
+  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ) rc = sqlite3BtreeBeginTrans(pBt, 1, 0);
+  }
+  return rc;
+}
+
+static int dbpageUpdate(
+  sqlite3_vtab *pVtab,
+  int argc,
+  sqlite3_value **argv,
+  sqlite_int64 *pRowid
+){
+  DbpageTable *pTab = (DbpageTable *)pVtab;
+  Pgno pgno;
+  DbPage *pDbPage = 0;
+  int rc = SQLITE_OK;
+  char *zErr = 0;
+  int iDb;
+  Btree *pBt;
+  Pager *pPager;
+  int szPage;
+  int isInsert;
+
+  (void)pRowid;
+  if( pTab->db->flags & SQLITE_Defensive ){
+    zErr = "read-only";
+    goto update_fail;
+  }
+  if( argc==1 ){
+    zErr = "cannot delete";
+    goto update_fail;
+  }
+  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
+    pgno = (Pgno)sqlite3_value_int(argv[2]);
+    isInsert = 1;
+  }else{
+    pgno = sqlite3_value_int(argv[0]);
+    if( (Pgno)sqlite3_value_int(argv[1])!=pgno ){
+      zErr = "cannot insert";
+      goto update_fail;
+    }
+    isInsert = 0;
+  }
+  if( sqlite3_value_type(argv[4])==SQLITE_NULL ){
+    iDb = 0;
+  }else{
+    const char *zSchema = (const char*)sqlite3_value_text(argv[4]);
+    iDb = sqlite3FindDbName(pTab->db, zSchema);
+    if( iDb<0 ){
+      zErr = "no such schema";
+      goto update_fail;
+    }
+  }
+  pBt = pTab->db->aDb[iDb].pBt;
+  if( pgno<1 || NEVER(pBt==0) ){
+    zErr = "bad page number";
+    goto update_fail;
+  }
+  szPage = sqlite3BtreeGetPageSize(pBt);
+  if( sqlite3_value_type(argv[3])!=SQLITE_BLOB
+   || sqlite3_value_bytes(argv[3])!=szPage
+  ){
+    if( sqlite3_value_type(argv[3])==SQLITE_NULL && isInsert && pgno>1 ){
+      /* "INSERT INTO dbpage($PGNO,NULL)" causes page number $PGNO and
+      ** all subsequent pages to be deleted. */
+      pTab->iDbTrunc = iDb;
+      pgno--;
+      pTab->pgnoTrunc = pgno;
+    }else{
+      zErr = "bad page value";
+      goto update_fail;
+    }
+  }
+
+  if( dbpageBeginTrans(pTab)!=SQLITE_OK ){
+    zErr = "failed to open transaction";
+    goto update_fail;
+  }
+
+  pPager = sqlite3BtreePager(pBt);
+  rc = sqlite3PagerGet(pPager, pgno, (DbPage**)&pDbPage, 0);
+  if( rc==SQLITE_OK ){
+    const void *pData = sqlite3_value_blob(argv[3]);
+    if( (rc = sqlite3PagerWrite(pDbPage))==SQLITE_OK && pData ){
+      unsigned char *aPage = sqlite3PagerGetData(pDbPage);
+      memcpy(aPage, pData, szPage);
+      pTab->pgnoTrunc = 0;
+    }
+  }else{
+    pTab->pgnoTrunc = 0;
+  }
+  sqlite3PagerUnref(pDbPage);
+  return rc;
+
+update_fail:
+  pTab->pgnoTrunc = 0;
+  sqlite3_free(pVtab->zErrMsg);
+  pVtab->zErrMsg = sqlite3_mprintf("%s", zErr);
+  return SQLITE_ERROR;
+}
+
+static int dbpageBegin(sqlite3_vtab *pVtab){
+  DbpageTable *pTab = (DbpageTable *)pVtab;
+  pTab->pgnoTrunc = 0;
+  return SQLITE_OK;
+}
+
+/* Invoke sqlite3PagerTruncate() as necessary, just prior to COMMIT
+*/
+static int dbpageSync(sqlite3_vtab *pVtab){
+  DbpageTable *pTab = (DbpageTable *)pVtab;
+  if( pTab->pgnoTrunc>0 ){
+    Btree *pBt = pTab->db->aDb[pTab->iDbTrunc].pBt;
+    Pager *pPager = sqlite3BtreePager(pBt);
+    sqlite3BtreeEnter(pBt);
+    if( pTab->pgnoTrunc<sqlite3BtreeLastPage(pBt) ){
+      sqlite3PagerTruncateImage(pPager, pTab->pgnoTrunc);
+    }
+    sqlite3BtreeLeave(pBt);
+  }
+  pTab->pgnoTrunc = 0;
+  return SQLITE_OK;
+}
+
+/* Cancel any pending truncate.
+*/
+static int dbpageRollbackTo(sqlite3_vtab *pVtab, int notUsed1){
+  DbpageTable *pTab = (DbpageTable *)pVtab;
+  pTab->pgnoTrunc = 0;
+  (void)notUsed1;
+  return SQLITE_OK;
+}
+
+/*
+** Invoke this routine to register the "dbpage" virtual table module
+*/
+SQLITE_PRIVATE int sqlite3DbpageRegister(sqlite3 *db){
+  static sqlite3_module dbpage_module = {
+    2,                            /* iVersion */
+    dbpageConnect,                /* xCreate */
+    dbpageConnect,                /* xConnect */
+    dbpageBestIndex,              /* xBestIndex */
+    dbpageDisconnect,             /* xDisconnect */
+    dbpageDisconnect,             /* xDestroy */
+    dbpageOpen,                   /* xOpen - open a cursor */
+    dbpageClose,                  /* xClose - close a cursor */
+    dbpageFilter,                 /* xFilter - configure scan constraints */
+    dbpageNext,                   /* xNext - advance a cursor */
+    dbpageEof,                    /* xEof - check for end of scan */
+    dbpageColumn,                 /* xColumn - read data */
+    dbpageRowid,                  /* xRowid - read data */
+    dbpageUpdate,                 /* xUpdate */
+    dbpageBegin,                  /* xBegin */
+    dbpageSync,                   /* xSync */
+    0,                            /* xCommit */
+    0,                            /* xRollback */
+    0,                            /* xFindMethod */
+    0,                            /* xRename */
+    0,                            /* xSavepoint */
+    0,                            /* xRelease */
+    dbpageRollbackTo,             /* xRollbackTo */
+    0,                            /* xShadowName */
+    0                             /* xIntegrity */
+  };
+  return sqlite3_create_module(db, "sqlite_dbpage", &dbpage_module, 0);
+}
+#elif defined(SQLITE_ENABLE_DBPAGE_VTAB)
+SQLITE_PRIVATE int sqlite3DbpageRegister(sqlite3 *db){ return SQLITE_OK; }
+#endif /* SQLITE_ENABLE_DBSTAT_VTAB */
+
+/************** End of dbpage.c **********************************************/
+/************** Begin file sqlite3session.c **********************************/
+
+#if defined(SQLITE_ENABLE_SESSION) && defined(SQLITE_ENABLE_PREUPDATE_HOOK)
+/* #include "sqlite3session.h" */
+/* #include <assert.h> */
+/* #include <string.h> */
+
+#ifndef SQLITE_AMALGAMATION
+/* # include "sqliteInt.h" */
+/* # include "vdbeInt.h" */
+#endif
+
+typedef struct SessionTable SessionTable;
+typedef struct SessionChange SessionChange;
+typedef struct SessionBuffer SessionBuffer;
+typedef struct SessionInput SessionInput;
+
+/*
+** Minimum chunk size used by streaming versions of functions.
+*/
+#ifndef SESSIONS_STRM_CHUNK_SIZE
+# ifdef SQLITE_TEST
+#   define SESSIONS_STRM_CHUNK_SIZE 64
+# else
+#   define SESSIONS_STRM_CHUNK_SIZE 1024
+# endif
+#endif
+
+#define SESSIONS_ROWID "_rowid_"
+
+static int sessions_strm_chunk_size = SESSIONS_STRM_CHUNK_SIZE;
+
+typedef struct SessionHook SessionHook;
+struct SessionHook {
+  void *pCtx;
+  int (*xOld)(void*,int,sqlite3_value**);
+  int (*xNew)(void*,int,sqlite3_value**);
+  int (*xCount)(void*);
+  int (*xDepth)(void*);
+};
+
+/*
+** Session handle structure.
+*/
+struct sqlite3_session {
+  sqlite3 *db;                    /* Database handle session is attached to */
+  char *zDb;                      /* Name of database session is attached to */
+  int bEnableSize;                /* True if changeset_size() enabled */
+  int bEnable;                    /* True if currently recording */
+  int bIndirect;                  /* True if all changes are indirect */
+  int bAutoAttach;                /* True to auto-attach tables */
+  int bImplicitPK;                /* True to handle tables with implicit PK */
+  int rc;                         /* Non-zero if an error has occurred */
+  void *pFilterCtx;               /* First argument to pass to xTableFilter */
+  int (*xTableFilter)(void *pCtx, const char *zTab);
+  i64 nMalloc;                    /* Number of bytes of data allocated */
+  i64 nMaxChangesetSize;
+  sqlite3_value *pZeroBlob;       /* Value containing X'' */
+  sqlite3_session *pNext;         /* Next session object on same db. */
+  SessionTable *pTable;           /* List of attached tables */
+  SessionHook hook;               /* APIs to grab new and old data with */
+};
+
+/*
+** Instances of this structure are used to build strings or binary records.
+*/
+struct SessionBuffer {
+  u8 *aBuf;                       /* Pointer to changeset buffer */
+  int nBuf;                       /* Size of buffer aBuf */
+  int nAlloc;                     /* Size of allocation containing aBuf */
+};
+
+/*
+** An object of this type is used internally as an abstraction for
+** input data. Input data may be supplied either as a single large buffer
+** (e.g. sqlite3changeset_start()) or using a stream function (e.g.
+**  sqlite3changeset_start_strm()).
+**
+** bNoDiscard:
+**   If true, then the only time data is discarded is as a result of explicit
+**   sessionDiscardData() calls. Not within every sessionInputBuffer() call.
+*/
+struct SessionInput {
+  int bNoDiscard;                 /* If true, do not discard in InputBuffer() */
+  int iCurrent;                   /* Offset in aData[] of current change */
+  int iNext;                      /* Offset in aData[] of next change */
+  u8 *aData;                      /* Pointer to buffer containing changeset */
+  int nData;                      /* Number of bytes in aData */
+
+  SessionBuffer buf;              /* Current read buffer */
+  int (*xInput)(void*, void*, int*);        /* Input stream call (or NULL) */
+  void *pIn;                                /* First argument to xInput */
+  int bEof;                       /* Set to true after xInput finished */
+};
+
+/*
+** Structure for changeset iterators.
+*/
+struct sqlite3_changeset_iter {
+  SessionInput in;                /* Input buffer or stream */
+  SessionBuffer tblhdr;           /* Buffer to hold apValue/zTab/abPK/ */
+  int bPatchset;                  /* True if this is a patchset */
+  int bInvert;                    /* True to invert changeset */
+  int bSkipEmpty;                 /* Skip noop UPDATE changes */
+  int rc;                         /* Iterator error code */
+  sqlite3_stmt *pConflict;        /* Points to conflicting row, if any */
+  char *zTab;                     /* Current table */
+  int nCol;                       /* Number of columns in zTab */
+  int op;                         /* Current operation */
+  int bIndirect;                  /* True if current change was indirect */
+  u8 *abPK;                       /* Primary key array */
+  sqlite3_value **apValue;        /* old.* and new.* values */
+};
+
+/*
+** Each session object maintains a set of the following structures, one
+** for each table the session object is monitoring. The structures are
+** stored in a linked list starting at sqlite3_session.pTable.
+**
+** The keys of the SessionTable.aChange[] hash table are all rows that have
+** been modified in any way since the session object was attached to the
+** table.
+**
+** The data associated with each hash-table entry is a structure containing
+** a subset of the initial values that the modified row contained at the
+** start of the session. Or no initial values if the row was inserted.
+**
+** pDfltStmt:
+**   This is only used by the sqlite3changegroup_xxx() APIs, not by
+**   regular sqlite3_session objects. It is a SELECT statement that
+**   selects the default value for each table column. For example,
+**   if the table is
+**
+**      CREATE TABLE xx(a DEFAULT 1, b, c DEFAULT 'abc')
+**
+**   then this variable is the compiled version of:
+**
+**      SELECT 1, NULL, 'abc'
+*/
+struct SessionTable {
+  SessionTable *pNext;
+  char *zName;                    /* Local name of table */
+  int nCol;                       /* Number of non-hidden columns */
+  int nTotalCol;                  /* Number of columns including hidden */
+  int bStat1;                     /* True if this is sqlite_stat1 */
+  int bRowid;                     /* True if this table uses rowid for PK */
+  const char **azCol;             /* Column names */
+  const char **azDflt;            /* Default value expressions */
+  int *aiIdx;                     /* Index to pass to xNew/xOld */
+  u8 *abPK;                       /* Array of primary key flags */
+  int nEntry;                     /* Total number of entries in hash table */
+  int nChange;                    /* Size of apChange[] array */
+  SessionChange **apChange;       /* Hash table buckets */
+  sqlite3_stmt *pDfltStmt;
+};
+
+/*
+** RECORD FORMAT:
+**
+** The following record format is similar to (but not compatible with) that
+** used in SQLite database files. This format is used as part of the
+** change-set binary format, and so must be architecture independent.
+**
+** Unlike the SQLite database record format, each field is self-contained -
+** there is no separation of header and data. Each field begins with a
+** single byte describing its type, as follows:
+**
+**       0x00: Undefined value.
+**       0x01: Integer value.
+**       0x02: Real value.
+**       0x03: Text value.
+**       0x04: Blob value.
+**       0x05: SQL NULL value.
+**
+** Note that the above match the definitions of SQLITE_INTEGER, SQLITE_TEXT
+** and so on in sqlite3.h. For undefined and NULL values, the field consists
+** only of the single type byte. For other types of values, the type byte
+** is followed by:
+**
+**   Text values:
+**     A varint containing the number of bytes in the value (encoded using
+**     UTF-8). Followed by a buffer containing the UTF-8 representation
+**     of the text value. There is no nul terminator.
+**
+**   Blob values:
+**     A varint containing the number of bytes in the value, followed by
+**     a buffer containing the value itself.
+**
+**   Integer values:
+**     An 8-byte big-endian integer value.
+**
+**   Real values:
+**     An 8-byte big-endian IEEE 754-2008 real value.
+**
+** Varint values are encoded in the same way as varints in the SQLite
+** record format.
+**
+** CHANGESET FORMAT:
+**
+** A changeset is a collection of DELETE, UPDATE and INSERT operations on
+** one or more tables. Operations on a single table are grouped together,
+** but may occur in any order (i.e. deletes, updates and inserts are all
+** mixed together).
+**
+** Each group of changes begins with a table header:
+**
+**   1 byte: Constant 0x54 (capital 'T')
+**   Varint: Number of columns in the table.
+**   nCol bytes: 0x01 for PK columns, 0x00 otherwise.
+**   N bytes: Unqualified table name (encoded using UTF-8). Nul-terminated.
+**
+** Followed by one or more changes to the table.
+**
+**   1 byte: Either SQLITE_INSERT (0x12), UPDATE (0x17) or DELETE (0x09).
+**   1 byte: The "indirect-change" flag.
+**   old.* record: (delete and update only)
+**   new.* record: (insert and update only)
+**
+** The "old.*" and "new.*" records, if present, are N field records in the
+** format described above under "RECORD FORMAT", where N is the number of
+** columns in the table. The i'th field of each record is associated with
+** the i'th column of the table, counting from left to right in the order
+** in which columns were declared in the CREATE TABLE statement.
+**
+** The new.* record that is part of each INSERT change contains the values
+** that make up the new row. Similarly, the old.* record that is part of each
+** DELETE change contains the values that made up the row that was deleted
+** from the database. In the changeset format, the records that are part
+** of INSERT or DELETE changes never contain any undefined (type byte 0x00)
+** fields.
+**
+** Within the old.* record associated with an UPDATE change, all fields
+** associated with table columns that are not PRIMARY KEY columns and are
+** not modified by the UPDATE change are set to "undefined". Other fields
+** are set to the values that made up the row before the UPDATE that the
+** change records took place. Within the new.* record, fields associated
+** with table columns modified by the UPDATE change contain the new
+** values. Fields associated with table columns that are not modified
+** are set to "undefined".
+**
+** PATCHSET FORMAT:
+**
+** A patchset is also a collection of changes. It is similar to a changeset,
+** but leaves undefined those fields that are not useful if no conflict
+** resolution is required when applying the changeset.
+**
+** Each group of changes begins with a table header:
+**
+**   1 byte: Constant 0x50 (capital 'P')
+**   Varint: Number of columns in the table.
+**   nCol bytes: 0x01 for PK columns, 0x00 otherwise.
+**   N bytes: Unqualified table name (encoded using UTF-8). Nul-terminated.
+**
+** Followed by one or more changes to the table.
+**
+**   1 byte: Either SQLITE_INSERT (0x12), UPDATE (0x17) or DELETE (0x09).
+**   1 byte: The "indirect-change" flag.
+**   single record: (PK fields for DELETE, PK and modified fields for UPDATE,
+**                   full record for INSERT).
+**
+** As in the changeset format, each field of the single record that is part
+** of a patchset change is associated with the correspondingly positioned
+** table column, counting from left to right within the CREATE TABLE
+** statement.
+**
+** For a DELETE change, all fields within the record except those associated
+** with PRIMARY KEY columns are omitted. The PRIMARY KEY fields contain the
+** values identifying the row to delete.
+**
+** For an UPDATE change, all fields except those associated with PRIMARY KEY
+** columns and columns that are modified by the UPDATE are set to "undefined".
+** PRIMARY KEY fields contain the values identifying the table row to update,
+** and fields associated with modified columns contain the new column values.
+**
+** The records associated with INSERT changes are in the same format as for
+** changesets. It is not possible for a record associated with an INSERT
+** change to contain a field set to "undefined".
+**
+** REBASE BLOB FORMAT:
+**
+** A rebase blob may be output by sqlite3changeset_apply_v2() and its
+** streaming equivalent for use with the sqlite3_rebaser APIs to rebase
+** existing changesets. A rebase blob contains one entry for each conflict
+** resolved using either the OMIT or REPLACE strategies within the apply_v2()
+** call.
+**
+** The format used for a rebase blob is very similar to that used for
+** changesets. All entries related to a single table are grouped together.
+**
+** Each group of entries begins with a table header in changeset format:
+**
+**   1 byte: Constant 0x54 (capital 'T')
+**   Varint: Number of columns in the table.
+**   nCol bytes: 0x01 for PK columns, 0x00 otherwise.
+**   N bytes: Unqualified table name (encoded using UTF-8). Nul-terminated.
+**
+** Followed by one or more entries associated with the table.
+**
+**   1 byte: Either SQLITE_INSERT (0x12), DELETE (0x09).
+**   1 byte: Flag. 0x01 for REPLACE, 0x00 for OMIT.
+**   record: (in the record format defined above).
+**
+** In a rebase blob, the first field is set to SQLITE_INSERT if the change
+** that caused the conflict was an INSERT or UPDATE, or to SQLITE_DELETE if
+** it was a DELETE. The second field is set to 0x01 if the conflict
+** resolution strategy was REPLACE, or 0x00 if it was OMIT.
+**
+** If the change that caused the conflict was a DELETE, then the single
+** record is a copy of the old.* record from the original changeset. If it
+** was an INSERT, then the single record is a copy of the new.* record. If
+** the conflicting change was an UPDATE, then the single record is a copy
+** of the new.* record with the PK fields filled in based on the original
+** old.* record.
+*/
+
+/*
+** For each row modified during a session, there exists a single instance of
+** this structure stored in a SessionTable.aChange[] hash table.
+*/
+struct SessionChange {
+  u8 op;                          /* One of UPDATE, DELETE, INSERT */
+  u8 bIndirect;                   /* True if this change is "indirect" */
+  u16 nRecordField;               /* Number of fields in aRecord[] */
+  int nMaxSize;                   /* Max size of eventual changeset record */
+  int nRecord;                    /* Number of bytes in buffer aRecord[] */
+  u8 *aRecord;                    /* Buffer containing old.* record */
+  SessionChange *pNext;           /* For hash-table collisions */
+};
+
+/*
+** Write a varint with value iVal into the buffer at aBuf. Return the
+** number of bytes written.
+*/
+static int sessionVarintPut(u8 *aBuf, int iVal){
+  return putVarint32(aBuf, iVal);
+}
+
+/*
+** Return the number of bytes required to store value iVal as a varint.
+*/
+static int sessionVarintLen(int iVal){
+  return sqlite3VarintLen(iVal);
+}
+
+/*
+** Read a varint value from aBuf[] into *piVal. Return the number of
+** bytes read.
+*/
+static int sessionVarintGet(const u8 *aBuf, int *piVal){
+  return getVarint32(aBuf, *piVal);
+}
+
+/* Load an unaligned and unsigned 32-bit integer */
+#define SESSION_UINT32(x) (((u32)(x)[0]<<24)|((x)[1]<<16)|((x)[2]<<8)|(x)[3])
+
+/*
+** Read a 64-bit big-endian integer value from buffer aRec[]. Return
+** the value read.
+*/
+static sqlite3_int64 sessionGetI64(u8 *aRec){
+  u64 x = SESSION_UINT32(aRec);
+  u32 y = SESSION_UINT32(aRec+4);
+  x = (x<<32) + y;
+  return (sqlite3_int64)x;
+}
+
+/*
+** Write a 64-bit big-endian integer value to the buffer aBuf[].
+*/
+static void sessionPutI64(u8 *aBuf, sqlite3_int64 i){
+  aBuf[0] = (i>>56) & 0xFF;
+  aBuf[1] = (i>>48) & 0xFF;
+  aBuf[2] = (i>>40) & 0xFF;
+  aBuf[3] = (i>>32) & 0xFF;
+  aBuf[4] = (i>>24) & 0xFF;
+  aBuf[5] = (i>>16) & 0xFF;
+  aBuf[6] = (i>> 8) & 0xFF;
+  aBuf[7] = (i>> 0) & 0xFF;
+}
+
+/*
+** This function is used to serialize the contents of value pValue (see
+** comment titled "RECORD FORMAT" above).
+**
+** If it is non-NULL, the serialized form of the value is written to
+** buffer aBuf. *pnWrite is set to the number of bytes written before
+** returning. Or, if aBuf is NULL, the only thing this function does is
+** set *pnWrite.
+**
+** If no error occurs, SQLITE_OK is returned. Or, if an OOM error occurs
+** within a call to sqlite3_value_text() (may fail if the db is utf-16))
+** SQLITE_NOMEM is returned.
+*/
+static int sessionSerializeValue(
+  u8 *aBuf,                       /* If non-NULL, write serialized value here */
+  sqlite3_value *pValue,          /* Value to serialize */
+  sqlite3_int64 *pnWrite          /* IN/OUT: Increment by bytes written */
+){
+  int nByte;                      /* Size of serialized value in bytes */
+
+  if( pValue ){
+    int eType;                    /* Value type (SQLITE_NULL, TEXT etc.) */
+
+    eType = sqlite3_value_type(pValue);
+    if( aBuf ) aBuf[0] = eType;
+
+    switch( eType ){
+      case SQLITE_NULL:
+        nByte = 1;
+        break;
+
+      case SQLITE_INTEGER:
+      case SQLITE_FLOAT:
+        if( aBuf ){
+          /* TODO: SQLite does something special to deal with mixed-endian
+          ** floating point values (e.g. ARM7). This code probably should
+          ** too.  */
+          u64 i;
+          if( eType==SQLITE_INTEGER ){
+            i = (u64)sqlite3_value_int64(pValue);
+          }else{
+            double r;
+            assert( sizeof(double)==8 && sizeof(u64)==8 );
+            r = sqlite3_value_double(pValue);
+            memcpy(&i, &r, 8);
+          }
+          sessionPutI64(&aBuf[1], i);
+        }
+        nByte = 9;
+        break;
+
+      default: {
+        u8 *z;
+        int n;
+        int nVarint;
+
+        assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
+        if( eType==SQLITE_TEXT ){
+          z = (u8 *)sqlite3_value_text(pValue);
+        }else{
+          z = (u8 *)sqlite3_value_blob(pValue);
+        }
+        n = sqlite3_value_bytes(pValue);
+        if( z==0 && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM;
+        nVarint = sessionVarintLen(n);
+
+        if( aBuf ){
+          sessionVarintPut(&aBuf[1], n);
+          if( n>0 ) memcpy(&aBuf[nVarint + 1], z, n);
+        }
+
+        nByte = 1 + nVarint + n;
+        break;
+      }
+    }
+  }else{
+    nByte = 1;
+    if( aBuf ) aBuf[0] = '\0';
+  }
+
+  if( pnWrite ) *pnWrite += nByte;
+  return SQLITE_OK;
+}
+
+/*
+** Allocate and return a pointer to a buffer nByte bytes in size. If
+** pSession is not NULL, increase the sqlite3_session.nMalloc variable
+** by the number of bytes allocated.
+*/
+static void *sessionMalloc64(sqlite3_session *pSession, i64 nByte){
+  void *pRet = sqlite3_malloc64(nByte);
+  if( pSession ) pSession->nMalloc += sqlite3_msize(pRet);
+  return pRet;
+}
+
+/*
+** Free buffer pFree, which must have been allocated by an earlier
+** call to sessionMalloc64(). If pSession is not NULL, decrease the
+** sqlite3_session.nMalloc counter by the number of bytes freed.
+*/
+static void sessionFree(sqlite3_session *pSession, void *pFree){
+  if( pSession ) pSession->nMalloc -= sqlite3_msize(pFree);
+  sqlite3_free(pFree);
+}
+
+/*
+** This macro is used to calculate hash key values for data structures. In
+** order to use this macro, the entire data structure must be represented
+** as a series of unsigned integers. In order to calculate a hash-key value
+** for a data structure represented as three such integers, the macro may
+** then be used as follows:
+**
+**    int hash_key_value;
+**    hash_key_value = HASH_APPEND(0, <value 1>);
+**    hash_key_value = HASH_APPEND(hash_key_value, <value 2>);
+**    hash_key_value = HASH_APPEND(hash_key_value, <value 3>);
+**
+** In practice, the data structures this macro is used for are the primary
+** key values of modified rows.
+*/
+#define HASH_APPEND(hash, add) ((hash) << 3) ^ (hash) ^ (unsigned int)(add)
+
+/*
+** Append the hash of the 64-bit integer passed as the second argument to the
+** hash-key value passed as the first. Return the new hash-key value.
+*/
+static unsigned int sessionHashAppendI64(unsigned int h, i64 i){
+  h = HASH_APPEND(h, i & 0xFFFFFFFF);
+  return HASH_APPEND(h, (i>>32)&0xFFFFFFFF);
+}
+
+/*
+** Append the hash of the blob passed via the second and third arguments to
+** the hash-key value passed as the first. Return the new hash-key value.
+*/
+static unsigned int sessionHashAppendBlob(unsigned int h, int n, const u8 *z){
+  int i;
+  for(i=0; i<n; i++) h = HASH_APPEND(h, z[i]);
+  return h;
+}
+
+/*
+** Append the hash of the data type passed as the second argument to the
+** hash-key value passed as the first. Return the new hash-key value.
+*/
+static unsigned int sessionHashAppendType(unsigned int h, int eType){
+  return HASH_APPEND(h, eType);
+}
+
+/*
+** This function may only be called from within a pre-update callback.
+** It calculates a hash based on the primary key values of the old.* or
+** new.* row currently available and, assuming no error occurs, writes it to
+** *piHash before returning. If the primary key contains one or more NULL
+** values, *pbNullPK is set to true before returning.
+**
+** If an error occurs, an SQLite error code is returned and the final values
+** of *piHash asn *pbNullPK are undefined. Otherwise, SQLITE_OK is returned
+** and the output variables are set as described above.
+*/
+static int sessionPreupdateHash(
+  sqlite3_session *pSession,      /* Session object that owns pTab */
+  i64 iRowid,
+  SessionTable *pTab,             /* Session table handle */
+  int bNew,                       /* True to hash the new.* PK */
+  int *piHash,                    /* OUT: Hash value */
+  int *pbNullPK                   /* OUT: True if there are NULL values in PK */
+){
+  unsigned int h = 0;             /* Hash value to return */
+  int i;                          /* Used to iterate through columns */
+
+  assert( pTab->nTotalCol==pSession->hook.xCount(pSession->hook.pCtx) );
+  if( pTab->bRowid ){
+    h = sessionHashAppendI64(h, iRowid);
+  }else{
+    assert( *pbNullPK==0 );
+    for(i=0; i<pTab->nCol; i++){
+      if( pTab->abPK[i] ){
+        int rc;
+        int eType;
+        sqlite3_value *pVal;
+        int iIdx = pTab->aiIdx[i];
+
+        if( bNew ){
+          rc = pSession->hook.xNew(pSession->hook.pCtx, iIdx, &pVal);
+        }else{
+          rc = pSession->hook.xOld(pSession->hook.pCtx, iIdx, &pVal);
+        }
+        if( rc!=SQLITE_OK ) return rc;
+
+        eType = sqlite3_value_type(pVal);
+        h = sessionHashAppendType(h, eType);
+        if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+          i64 iVal;
+          if( eType==SQLITE_INTEGER ){
+            iVal = sqlite3_value_int64(pVal);
+          }else{
+            double rVal = sqlite3_value_double(pVal);
+            assert( sizeof(iVal)==8 && sizeof(rVal)==8 );
+            memcpy(&iVal, &rVal, 8);
+          }
+          h = sessionHashAppendI64(h, iVal);
+        }else if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
+          const u8 *z;
+          int n;
+          if( eType==SQLITE_TEXT ){
+            z = (const u8 *)sqlite3_value_text(pVal);
+          }else{
+            z = (const u8 *)sqlite3_value_blob(pVal);
+          }
+          n = sqlite3_value_bytes(pVal);
+          if( !z && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM;
+          h = sessionHashAppendBlob(h, n, z);
+        }else{
+          assert( eType==SQLITE_NULL );
+          assert( pTab->bStat1==0 || i!=1 );
+          *pbNullPK = 1;
+        }
+      }
+    }
+  }
+
+  *piHash = (h % pTab->nChange);
+  return SQLITE_OK;
+}
+
+/*
+** The buffer that the argument points to contains a serialized SQL value.
+** Return the number of bytes of space occupied by the value (including
+** the type byte).
+*/
+static int sessionSerialLen(const u8 *a){
+  int e;
+  int n;
+  assert( a!=0 );
+  e = *a;
+  if( e==0 || e==0xFF ) return 1;
+  if( e==SQLITE_NULL ) return 1;
+  if( e==SQLITE_INTEGER || e==SQLITE_FLOAT ) return 9;
+  return sessionVarintGet(&a[1], &n) + 1 + n;
+}
+
+/*
+** Based on the primary key values stored in change aRecord, calculate a
+** hash key. Assume the has table has nBucket buckets. The hash keys
+** calculated by this function are compatible with those calculated by
+** sessionPreupdateHash().
+**
+** The bPkOnly argument is non-zero if the record at aRecord[] is from
+** a patchset DELETE. In this case the non-PK fields are omitted entirely.
+*/
+static unsigned int sessionChangeHash(
+  SessionTable *pTab,             /* Table handle */
+  int bPkOnly,                    /* Record consists of PK fields only */
+  u8 *aRecord,                    /* Change record */
+  int nBucket                     /* Assume this many buckets in hash table */
+){
+  unsigned int h = 0;             /* Value to return */
+  int i;                          /* Used to iterate through columns */
+  u8 *a = aRecord;                /* Used to iterate through change record */
+
+  for(i=0; i<pTab->nCol; i++){
+    int eType = *a;
+    int isPK = pTab->abPK[i];
+    if( bPkOnly && isPK==0 ) continue;
+
+    /* It is not possible for eType to be SQLITE_NULL here. The session
+    ** module does not record changes for rows with NULL values stored in
+    ** primary key columns. */
+    assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT
+         || eType==SQLITE_TEXT || eType==SQLITE_BLOB
+         || eType==SQLITE_NULL || eType==0
+    );
+    assert( !isPK || (eType!=0 && eType!=SQLITE_NULL) );
+
+    if( isPK ){
+      a++;
+      h = sessionHashAppendType(h, eType);
+      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+        h = sessionHashAppendI64(h, sessionGetI64(a));
+        a += 8;
+      }else{
+        int n;
+        a += sessionVarintGet(a, &n);
+        h = sessionHashAppendBlob(h, n, a);
+        a += n;
+      }
+    }else{
+      a += sessionSerialLen(a);
+    }
+  }
+  return (h % nBucket);
+}
+
+/*
+** Arguments aLeft and aRight are pointers to change records for table pTab.
+** This function returns true if the two records apply to the same row (i.e.
+** have the same values stored in the primary key columns), or false
+** otherwise.
+*/
+static int sessionChangeEqual(
+  SessionTable *pTab,             /* Table used for PK definition */
+  int bLeftPkOnly,                /* True if aLeft[] contains PK fields only */
+  u8 *aLeft,                      /* Change record */
+  int bRightPkOnly,               /* True if aRight[] contains PK fields only */
+  u8 *aRight                      /* Change record */
+){
+  u8 *a1 = aLeft;                 /* Cursor to iterate through aLeft */
+  u8 *a2 = aRight;                /* Cursor to iterate through aRight */
+  int iCol;                       /* Used to iterate through table columns */
+
+  for(iCol=0; iCol<pTab->nCol; iCol++){
+    if( pTab->abPK[iCol] ){
+      int n1 = sessionSerialLen(a1);
+      int n2 = sessionSerialLen(a2);
+
+      if( n1!=n2 || memcmp(a1, a2, n1) ){
+        return 0;
+      }
+      a1 += n1;
+      a2 += n2;
+    }else{
+      if( bLeftPkOnly==0 ) a1 += sessionSerialLen(a1);
+      if( bRightPkOnly==0 ) a2 += sessionSerialLen(a2);
+    }
+  }
+
+  return 1;
+}
+
+/*
+** Arguments aLeft and aRight both point to buffers containing change
+** records with nCol columns. This function "merges" the two records into
+** a single records which is written to the buffer at *paOut. *paOut is
+** then set to point to one byte after the last byte written before
+** returning.
+**
+** The merging of records is done as follows: For each column, if the
+** aRight record contains a value for the column, copy the value from
+** their. Otherwise, if aLeft contains a value, copy it. If neither
+** record contains a value for a given column, then neither does the
+** output record.
+*/
+static void sessionMergeRecord(
+  u8 **paOut,
+  int nCol,
+  u8 *aLeft,
+  u8 *aRight
+){
+  u8 *a1 = aLeft;                 /* Cursor used to iterate through aLeft */
+  u8 *a2 = aRight;                /* Cursor used to iterate through aRight */
+  u8 *aOut = *paOut;              /* Output cursor */
+  int iCol;                       /* Used to iterate from 0 to nCol */
+
+  for(iCol=0; iCol<nCol; iCol++){
+    int n1 = sessionSerialLen(a1);
+    int n2 = sessionSerialLen(a2);
+    if( *a2 ){
+      memcpy(aOut, a2, n2);
+      aOut += n2;
+    }else{
+      memcpy(aOut, a1, n1);
+      aOut += n1;
+    }
+    a1 += n1;
+    a2 += n2;
+  }
+
+  *paOut = aOut;
+}
+
+/*
+** This is a helper function used by sessionMergeUpdate().
+**
+** When this function is called, both *paOne and *paTwo point to a value
+** within a change record. Before it returns, both have been advanced so
+** as to point to the next value in the record.
+**
+** If, when this function is called, *paTwo points to a valid value (i.e.
+** *paTwo[0] is not 0x00 - the "no value" placeholder), a copy of the *paTwo
+** pointer is returned and *pnVal is set to the number of bytes in the
+** serialized value. Otherwise, a copy of *paOne is returned and *pnVal
+** set to the number of bytes in the value at *paOne. If *paOne points
+** to the "no value" placeholder, *pnVal is set to 1. In other words:
+**
+**   if( *paTwo is valid ) return *paTwo;
+**   return *paOne;
+**
+*/
+static u8 *sessionMergeValue(
+  u8 **paOne,                     /* IN/OUT: Left-hand buffer pointer */
+  u8 **paTwo,                     /* IN/OUT: Right-hand buffer pointer */
+  int *pnVal                      /* OUT: Bytes in returned value */
+){
+  u8 *a1 = *paOne;
+  u8 *a2 = *paTwo;
+  u8 *pRet = 0;
+  int n1;
+
+  assert( a1 );
+  if( a2 ){
+    int n2 = sessionSerialLen(a2);
+    if( *a2 ){
+      *pnVal = n2;
+      pRet = a2;
+    }
+    *paTwo = &a2[n2];
+  }
+
+  n1 = sessionSerialLen(a1);
+  if( pRet==0 ){
+    *pnVal = n1;
+    pRet = a1;
+  }
+  *paOne = &a1[n1];
+
+  return pRet;
+}
+
+/*
+** This function is used by changeset_concat() to merge two UPDATE changes
+** on the same row.
+*/
+static int sessionMergeUpdate(
+  u8 **paOut,                     /* IN/OUT: Pointer to output buffer */
+  SessionTable *pTab,             /* Table change pertains to */
+  int bPatchset,                  /* True if records are patchset records */
+  u8 *aOldRecord1,                /* old.* record for first change */
+  u8 *aOldRecord2,                /* old.* record for second change */
+  u8 *aNewRecord1,                /* new.* record for first change */
+  u8 *aNewRecord2                 /* new.* record for second change */
+){
+  u8 *aOld1 = aOldRecord1;
+  u8 *aOld2 = aOldRecord2;
+  u8 *aNew1 = aNewRecord1;
+  u8 *aNew2 = aNewRecord2;
+
+  u8 *aOut = *paOut;
+  int i;
+
+  if( bPatchset==0 ){
+    int bRequired = 0;
+
+    assert( aOldRecord1 && aNewRecord1 );
+
+    /* Write the old.* vector first. */
+    for(i=0; i<pTab->nCol; i++){
+      int nOld;
+      u8 *aOld;
+      int nNew;
+      u8 *aNew;
+
+      aOld = sessionMergeValue(&aOld1, &aOld2, &nOld);
+      aNew = sessionMergeValue(&aNew1, &aNew2, &nNew);
+      if( pTab->abPK[i] || nOld!=nNew || memcmp(aOld, aNew, nNew) ){
+        if( pTab->abPK[i]==0 ) bRequired = 1;
+        memcpy(aOut, aOld, nOld);
+        aOut += nOld;
+      }else{
+        *(aOut++) = '\0';
+      }
+    }
+
+    if( !bRequired ) return 0;
+  }
+
+  /* Write the new.* vector */
+  aOld1 = aOldRecord1;
+  aOld2 = aOldRecord2;
+  aNew1 = aNewRecord1;
+  aNew2 = aNewRecord2;
+  for(i=0; i<pTab->nCol; i++){
+    int nOld;
+    u8 *aOld;
+    int nNew;
+    u8 *aNew;
+
+    aOld = sessionMergeValue(&aOld1, &aOld2, &nOld);
+    aNew = sessionMergeValue(&aNew1, &aNew2, &nNew);
+    if( bPatchset==0
+     && (pTab->abPK[i] || (nOld==nNew && 0==memcmp(aOld, aNew, nNew)))
+    ){
+      *(aOut++) = '\0';
+    }else{
+      memcpy(aOut, aNew, nNew);
+      aOut += nNew;
+    }
+  }
+
+  *paOut = aOut;
+  return 1;
+}
+
+/*
+** This function is only called from within a pre-update-hook callback.
+** It determines if the current pre-update-hook change affects the same row
+** as the change stored in argument pChange. If so, it returns true. Otherwise
+** if the pre-update-hook does not affect the same row as pChange, it returns
+** false.
+*/
+static int sessionPreupdateEqual(
+  sqlite3_session *pSession,      /* Session object that owns SessionTable */
+  i64 iRowid,                     /* Rowid value if pTab->bRowid */
+  SessionTable *pTab,             /* Table associated with change */
+  SessionChange *pChange,         /* Change to compare to */
+  int op                          /* Current pre-update operation */
+){
+  int iCol;                       /* Used to iterate through columns */
+  u8 *a = pChange->aRecord;       /* Cursor used to scan change record */
+
+  if( pTab->bRowid ){
+    if( a[0]!=SQLITE_INTEGER ) return 0;
+    return sessionGetI64(&a[1])==iRowid;
+  }
+
+  assert( op==SQLITE_INSERT || op==SQLITE_UPDATE || op==SQLITE_DELETE );
+  for(iCol=0; iCol<pTab->nCol; iCol++){
+    if( !pTab->abPK[iCol] ){
+      a += sessionSerialLen(a);
+    }else{
+      sqlite3_value *pVal;        /* Value returned by preupdate_new/old */
+      int rc;                     /* Error code from preupdate_new/old */
+      int eType = *a++;           /* Type of value from change record */
+      int iIdx = pTab->aiIdx[iCol];
+
+      /* The following calls to preupdate_new() and preupdate_old() can not
+      ** fail. This is because they cache their return values, and by the
+      ** time control flows to here they have already been called once from
+      ** within sessionPreupdateHash(). The first two asserts below verify
+      ** this (that the method has already been called). */
+      if( op==SQLITE_INSERT ){
+        /* assert( db->pPreUpdate->pNewUnpacked || db->pPreUpdate->aNew ); */
+        rc = pSession->hook.xNew(pSession->hook.pCtx, iIdx, &pVal);
+      }else{
+        /* assert( db->pPreUpdate->pUnpacked ); */
+        rc = pSession->hook.xOld(pSession->hook.pCtx, iIdx, &pVal);
+      }
+      assert( rc==SQLITE_OK );
+      (void)rc;                   /* Suppress warning about unused variable */
+      if( sqlite3_value_type(pVal)!=eType ) return 0;
+
+      /* A SessionChange object never has a NULL value in a PK column */
+      assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT
+           || eType==SQLITE_BLOB    || eType==SQLITE_TEXT
+      );
+
+      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+        i64 iVal = sessionGetI64(a);
+        a += 8;
+        if( eType==SQLITE_INTEGER ){
+          if( sqlite3_value_int64(pVal)!=iVal ) return 0;
+        }else{
+          double rVal;
+          assert( sizeof(iVal)==8 && sizeof(rVal)==8 );
+          memcpy(&rVal, &iVal, 8);
+          if( sqlite3_value_double(pVal)!=rVal ) return 0;
+        }
+      }else{
+        int n;
+        const u8 *z;
+        a += sessionVarintGet(a, &n);
+        if( sqlite3_value_bytes(pVal)!=n ) return 0;
+        if( eType==SQLITE_TEXT ){
+          z = sqlite3_value_text(pVal);
+        }else{
+          z = sqlite3_value_blob(pVal);
+        }
+        if( n>0 && memcmp(a, z, n) ) return 0;
+        a += n;
+      }
+    }
+  }
+
+  return 1;
+}
+
+/*
+** If required, grow the hash table used to store changes on table pTab
+** (part of the session pSession). If a fatal OOM error occurs, set the
+** session object to failed and return SQLITE_ERROR. Otherwise, return
+** SQLITE_OK.
+**
+** It is possible that a non-fatal OOM error occurs in this function. In
+** that case the hash-table does not grow, but SQLITE_OK is returned anyway.
+** Growing the hash table in this case is a performance optimization only,
+** it is not required for correct operation.
+*/
+static int sessionGrowHash(
+  sqlite3_session *pSession,      /* For memory accounting. May be NULL */
+  int bPatchset,
+  SessionTable *pTab
+){
+  if( pTab->nChange==0 || pTab->nEntry>=(pTab->nChange/2) ){
+    int i;
+    SessionChange **apNew;
+    sqlite3_int64 nNew = 2*(sqlite3_int64)(pTab->nChange ? pTab->nChange : 128);
+
+    apNew = (SessionChange**)sessionMalloc64(
+        pSession, sizeof(SessionChange*) * nNew
+    );
+    if( apNew==0 ){
+      if( pTab->nChange==0 ){
+        return SQLITE_ERROR;
+      }
+      return SQLITE_OK;
+    }
+    memset(apNew, 0, sizeof(SessionChange *) * nNew);
+
+    for(i=0; i<pTab->nChange; i++){
+      SessionChange *p;
+      SessionChange *pNext;
+      for(p=pTab->apChange[i]; p; p=pNext){
+        int bPkOnly = (p->op==SQLITE_DELETE && bPatchset);
+        int iHash = sessionChangeHash(pTab, bPkOnly, p->aRecord, nNew);
+        pNext = p->pNext;
+        p->pNext = apNew[iHash];
+        apNew[iHash] = p;
+      }
+    }
+
+    sessionFree(pSession, pTab->apChange);
+    pTab->nChange = nNew;
+    pTab->apChange = apNew;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** This function queries the database for the names of the columns of table
+** zThis, in schema zDb.
+**
+** Otherwise, if they are not NULL, variable *pnCol is set to the number
+** of columns in the database table and variable *pzTab is set to point to a
+** nul-terminated copy of the table name. *pazCol (if not NULL) is set to
+** point to an array of pointers to column names. And *pabPK (again, if not
+** NULL) is set to point to an array of booleans - true if the corresponding
+** column is part of the primary key.
+**
+** For example, if the table is declared as:
+**
+**     CREATE TABLE tbl1(w, x DEFAULT 'abc', y, z, PRIMARY KEY(w, z));
+**
+** Then the five output variables are populated as follows:
+**
+**     *pnCol  = 4
+**     *pzTab  = "tbl1"
+**     *pazCol = {"w", "x", "y", "z"}
+**     *pazDflt = {NULL, 'abc', NULL, NULL}
+**     *pabPK  = {1, 0, 0, 1}
+**
+** All returned buffers are part of the same single allocation, which must
+** be freed using sqlite3_free() by the caller
+*/
+static int sessionTableInfo(
+  sqlite3_session *pSession,      /* For memory accounting. May be NULL */
+  sqlite3 *db,                    /* Database connection */
+  const char *zDb,                /* Name of attached database (e.g. "main") */
+  const char *zThis,              /* Table name */
+  int *pnCol,                     /* OUT: number of columns */
+  int *pnTotalCol,                /* OUT: number of hidden columns */
+  const char **pzTab,             /* OUT: Copy of zThis */
+  const char ***pazCol,           /* OUT: Array of column names for table */
+  const char ***pazDflt,          /* OUT: Array of default value expressions */
+  int **paiIdx,                   /* OUT: Array of xNew/xOld indexes */
+  u8 **pabPK,                     /* OUT: Array of booleans - true for PK col */
+  int *pbRowid                    /* OUT: True if only PK is a rowid */
+){
+  char *zPragma;
+  sqlite3_stmt *pStmt;
+  int rc;
+  sqlite3_int64 nByte;
+  int nDbCol = 0;
+  int nThis;
+  int i;
+  u8 *pAlloc = 0;
+  char **azCol = 0;
+  char **azDflt = 0;
+  u8 *abPK = 0;
+  int *aiIdx = 0;
+  int bRowid = 0;                 /* Set to true to use rowid as PK */
+
+  assert( pazCol && pabPK );
+
+  *pazCol = 0;
+  *pabPK = 0;
+  *pnCol = 0;
+  if( pnTotalCol ) *pnTotalCol = 0;
+  if( paiIdx ) *paiIdx = 0;
+  if( pzTab ) *pzTab = 0;
+  if( pazDflt ) *pazDflt = 0;
+
+  nThis = sqlite3Strlen30(zThis);
+  if( nThis==12 && 0==sqlite3_stricmp("sqlite_stat1", zThis) ){
+    rc = sqlite3_table_column_metadata(db, zDb, zThis, 0, 0, 0, 0, 0, 0);
+    if( rc==SQLITE_OK ){
+      /* For sqlite_stat1, pretend that (tbl,idx) is the PRIMARY KEY. */
+      zPragma = sqlite3_mprintf(
+          "SELECT 0, 'tbl',  '', 0, '', 1, 0     UNION ALL "
+          "SELECT 1, 'idx',  '', 0, '', 2, 0     UNION ALL "
+          "SELECT 2, 'stat', '', 0, '', 0, 0"
+      );
+    }else if( rc==SQLITE_ERROR ){
+      zPragma = sqlite3_mprintf("");
+    }else{
+      return rc;
+    }
+  }else{
+    zPragma = sqlite3_mprintf("PRAGMA '%q'.table_xinfo('%q')", zDb, zThis);
+  }
+  if( !zPragma ){
+    return SQLITE_NOMEM;
+  }
+
+  rc = sqlite3_prepare_v2(db, zPragma, -1, &pStmt, 0);
+  sqlite3_free(zPragma);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+
+  nByte = nThis + 1;
+  bRowid = (pbRowid!=0);
+  while( SQLITE_ROW==sqlite3_step(pStmt) ){
+    nByte += sqlite3_column_bytes(pStmt, 1);          /* name */
+    nByte += sqlite3_column_bytes(pStmt, 4);          /* dflt_value */
+    if( sqlite3_column_int(pStmt, 6)==0 ){            /* !hidden */
+      nDbCol++;
+    }
+    if( sqlite3_column_int(pStmt, 5) ) bRowid = 0;    /* pk */
+  }
+  if( nDbCol==0 ) bRowid = 0;
+  nDbCol += bRowid;
+  nByte += strlen(SESSIONS_ROWID);
+  rc = sqlite3_reset(pStmt);
+
+  if( rc==SQLITE_OK ){
+    nByte += nDbCol * (sizeof(const char *)*2 +sizeof(int)+sizeof(u8) + 1 + 1);
+    pAlloc = sessionMalloc64(pSession, nByte);
+    if( pAlloc==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pAlloc, 0, nByte);
+    }
+  }
+  if( rc==SQLITE_OK ){
+    azCol = (char **)pAlloc;
+    azDflt = (char**)&azCol[nDbCol];
+    aiIdx = (int*)&azDflt[nDbCol];
+    abPK = (u8 *)&aiIdx[nDbCol];
+    pAlloc = &abPK[nDbCol];
+    if( pzTab ){
+      memcpy(pAlloc, zThis, nThis+1);
+      *pzTab = (char *)pAlloc;
+      pAlloc += nThis+1;
+    }
+
+    i = 0;
+    if( bRowid ){
+      size_t nName = strlen(SESSIONS_ROWID);
+      memcpy(pAlloc, SESSIONS_ROWID, nName+1);
+      azCol[i] = (char*)pAlloc;
+      pAlloc += nName+1;
+      abPK[i] = 1;
+      aiIdx[i] = -1;
+      i++;
+    }
+    while( SQLITE_ROW==sqlite3_step(pStmt) ){
+      if( sqlite3_column_int(pStmt, 6)==0 ){            /* !hidden */
+        int nName = sqlite3_column_bytes(pStmt, 1);
+        int nDflt = sqlite3_column_bytes(pStmt, 4);
+        const unsigned char *zName = sqlite3_column_text(pStmt, 1);
+        const unsigned char *zDflt = sqlite3_column_text(pStmt, 4);
+
+        if( zName==0 ) break;
+        memcpy(pAlloc, zName, nName+1);
+        azCol[i] = (char *)pAlloc;
+        pAlloc += nName+1;
+        if( zDflt ){
+          memcpy(pAlloc, zDflt, nDflt+1);
+          azDflt[i] = (char *)pAlloc;
+          pAlloc += nDflt+1;
+        }else{
+          azDflt[i] = 0;
+        }
+        abPK[i] = sqlite3_column_int(pStmt, 5);
+        aiIdx[i] = sqlite3_column_int(pStmt, 0);
+        i++;
+      }
+      if( pnTotalCol ) (*pnTotalCol)++;
+    }
+    rc = sqlite3_reset(pStmt);
+  }
+
+  /* If successful, populate the output variables. Otherwise, zero them and
+  ** free any allocation made. An error code will be returned in this case.
+  */
+  if( rc==SQLITE_OK ){
+    *pazCol = (const char**)azCol;
+    if( pazDflt ) *pazDflt = (const char**)azDflt;
+    *pabPK = abPK;
+    *pnCol = nDbCol;
+    if( paiIdx ) *paiIdx = aiIdx;
+  }else{
+    sessionFree(pSession, azCol);
+  }
+  if( pbRowid ) *pbRowid = bRowid;
+  sqlite3_finalize(pStmt);
+  return rc;
+}
+
+/*
+** This function is called to initialize the SessionTable.nCol, azCol[]
+** abPK[] and azDflt[] members of SessionTable object pTab. If these
+** fields are already initilialized, this function is a no-op.
+**
+** If an error occurs, an error code is stored in sqlite3_session.rc and
+** non-zero returned. Or, if no error occurs but the table has no primary
+** key, sqlite3_session.rc is left set to SQLITE_OK and non-zero returned to
+** indicate that updates on this table should be ignored. SessionTable.abPK
+** is set to NULL in this case.
+*/
+static int sessionInitTable(
+  sqlite3_session *pSession,      /* Optional session handle */
+  SessionTable *pTab,             /* Table object to initialize */
+  sqlite3 *db,                    /* Database handle to read schema from */
+  const char *zDb                 /* Name of db - "main", "temp" etc. */
+){
+  int rc = SQLITE_OK;
+
+  if( pTab->nCol==0 ){
+    u8 *abPK;
+    assert( pTab->azCol==0 || pTab->abPK==0 );
+    rc = sessionTableInfo(pSession, db, zDb,
+        pTab->zName, &pTab->nCol, &pTab->nTotalCol, 0, &pTab->azCol,
+        &pTab->azDflt, &pTab->aiIdx, &abPK,
+        ((pSession==0 || pSession->bImplicitPK) ? &pTab->bRowid : 0)
+    );
+    if( rc==SQLITE_OK ){
+      int i;
+      for(i=0; i<pTab->nCol; i++){
+        if( abPK[i] ){
+          pTab->abPK = abPK;
+          break;
+        }
+      }
+      if( 0==sqlite3_stricmp("sqlite_stat1", pTab->zName) ){
+        pTab->bStat1 = 1;
+      }
+
+      if( pSession && pSession->bEnableSize ){
+        pSession->nMaxChangesetSize += (
+          1 + sessionVarintLen(pTab->nCol) + pTab->nCol + strlen(pTab->zName)+1
+        );
+      }
+    }
+  }
+
+  if( pSession ){
+    pSession->rc = rc;
+    return (rc || pTab->abPK==0);
+  }
+  return rc;
+}
+
+/*
+** Re-initialize table object pTab.
+*/
+static int sessionReinitTable(sqlite3_session *pSession, SessionTable *pTab){
+  int nCol = 0;
+  int nTotalCol = 0;
+  const char **azCol = 0;
+  const char **azDflt = 0;
+  int *aiIdx = 0;
+  u8 *abPK = 0;
+  int bRowid = 0;
+
+  assert( pSession->rc==SQLITE_OK );
+
+  pSession->rc = sessionTableInfo(pSession, pSession->db, pSession->zDb,
+      pTab->zName, &nCol, &nTotalCol, 0, &azCol, &azDflt, &aiIdx, &abPK,
+      (pSession->bImplicitPK ? &bRowid : 0)
+  );
+  if( pSession->rc==SQLITE_OK ){
+    if( pTab->nCol>nCol || pTab->bRowid!=bRowid ){
+      pSession->rc = SQLITE_SCHEMA;
+    }else{
+      int ii;
+      int nOldCol = pTab->nCol;
+      for(ii=0; ii<nCol; ii++){
+        if( ii<pTab->nCol ){
+          if( pTab->abPK[ii]!=abPK[ii] ){
+            pSession->rc = SQLITE_SCHEMA;
+          }
+        }else if( abPK[ii] ){
+          pSession->rc = SQLITE_SCHEMA;
+        }
+      }
+
+      if( pSession->rc==SQLITE_OK ){
+        const char **a = pTab->azCol;
+        pTab->azCol = azCol;
+        pTab->nCol = nCol;
+        pTab->nTotalCol = nTotalCol;
+        pTab->azDflt = azDflt;
+        pTab->abPK = abPK;
+        pTab->aiIdx = aiIdx;
+        azCol = a;
+      }
+      if( pSession->bEnableSize ){
+        pSession->nMaxChangesetSize += (nCol - nOldCol);
+        pSession->nMaxChangesetSize += sessionVarintLen(nCol);
+        pSession->nMaxChangesetSize -= sessionVarintLen(nOldCol);
+      }
+    }
+  }
+
+  sqlite3_free((char*)azCol);
+  return pSession->rc;
+}
+
+/*
+** Session-change object (*pp) contains an old.* record with fewer than
+** nCol fields. This function updates it with the default values for
+** the missing fields.
+*/
+static void sessionUpdateOneChange(
+  sqlite3_session *pSession,      /* For memory accounting */
+  int *pRc,                       /* IN/OUT: Error code */
+  SessionChange **pp,             /* IN/OUT: Change object to update */
+  int nCol,                       /* Number of columns now in table */
+  sqlite3_stmt *pDflt             /* SELECT <default-values...> */
+){
+  SessionChange *pOld = *pp;
+
+  while( pOld->nRecordField<nCol ){
+    SessionChange *pNew = 0;
+    int nByte = 0;
+    int nIncr = 0;
+    int iField = pOld->nRecordField;
+    int eType = sqlite3_column_type(pDflt, iField);
+    switch( eType ){
+      case SQLITE_NULL:
+        nIncr = 1;
+        break;
+      case SQLITE_INTEGER:
+      case SQLITE_FLOAT:
+        nIncr = 9;
+        break;
+      default: {
+        int n = sqlite3_column_bytes(pDflt, iField);
+        nIncr = 1 + sessionVarintLen(n) + n;
+        assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
+        break;
+      }
+    }
+
+    nByte = nIncr + (sizeof(SessionChange) + pOld->nRecord);
+    pNew = sessionMalloc64(pSession, nByte);
+    if( pNew==0 ){
+      *pRc = SQLITE_NOMEM;
+      return;
+    }else{
+      memcpy(pNew, pOld, sizeof(SessionChange));
+      pNew->aRecord = (u8*)&pNew[1];
+      memcpy(pNew->aRecord, pOld->aRecord, pOld->nRecord);
+      pNew->aRecord[pNew->nRecord++] = (u8)eType;
+      switch( eType ){
+        case SQLITE_INTEGER: {
+          i64 iVal = sqlite3_column_int64(pDflt, iField);
+          sessionPutI64(&pNew->aRecord[pNew->nRecord], iVal);
+          pNew->nRecord += 8;
+          break;
+        }
+
+        case SQLITE_FLOAT: {
+          double rVal = sqlite3_column_double(pDflt, iField);
+          i64 iVal = 0;
+          memcpy(&iVal, &rVal, sizeof(rVal));
+          sessionPutI64(&pNew->aRecord[pNew->nRecord], iVal);
+          pNew->nRecord += 8;
+          break;
+        }
+
+        case SQLITE_TEXT: {
+          int n = sqlite3_column_bytes(pDflt, iField);
+          const char *z = (const char*)sqlite3_column_text(pDflt, iField);
+          pNew->nRecord += sessionVarintPut(&pNew->aRecord[pNew->nRecord], n);
+          memcpy(&pNew->aRecord[pNew->nRecord], z, n);
+          pNew->nRecord += n;
+          break;
+        }
+
+        case SQLITE_BLOB: {
+          int n = sqlite3_column_bytes(pDflt, iField);
+          const u8 *z = (const u8*)sqlite3_column_blob(pDflt, iField);
+          pNew->nRecord += sessionVarintPut(&pNew->aRecord[pNew->nRecord], n);
+          memcpy(&pNew->aRecord[pNew->nRecord], z, n);
+          pNew->nRecord += n;
+          break;
+        }
+
+        default:
+          assert( eType==SQLITE_NULL );
+          break;
+      }
+
+      sessionFree(pSession, pOld);
+      *pp = pOld = pNew;
+      pNew->nRecordField++;
+      pNew->nMaxSize += nIncr;
+      if( pSession ){
+        pSession->nMaxChangesetSize += nIncr;
+      }
+    }
+  }
+}
+
+/*
+** Ensure that there is room in the buffer to append nByte bytes of data.
+** If not, use sqlite3_realloc() to grow the buffer so that there is.
+**
+** If successful, return zero. Otherwise, if an OOM condition is encountered,
+** set *pRc to SQLITE_NOMEM and return non-zero.
+*/
+static int sessionBufferGrow(SessionBuffer *p, i64 nByte, int *pRc){
+#define SESSION_MAX_BUFFER_SZ (0x7FFFFF00 - 1)
+  i64 nReq = p->nBuf + nByte;
+  if( *pRc==SQLITE_OK && nReq>p->nAlloc ){
+    u8 *aNew;
+    i64 nNew = p->nAlloc ? p->nAlloc : 128;
+
+    do {
+      nNew = nNew*2;
+    }while( nNew<nReq );
+
+    /* The value of SESSION_MAX_BUFFER_SZ is copied from the implementation
+    ** of sqlite3_realloc64(). Allocations greater than this size in bytes
+    ** always fail. It is used here to ensure that this routine can always
+    ** allocate up to this limit - instead of up to the largest power of
+    ** two smaller than the limit.  */
+    if( nNew>SESSION_MAX_BUFFER_SZ ){
+      nNew = SESSION_MAX_BUFFER_SZ;
+      if( nNew<nReq ){
+        *pRc = SQLITE_NOMEM;
+        return 1;
+      }
+    }
+
+    aNew = (u8 *)sqlite3_realloc64(p->aBuf, nNew);
+    if( 0==aNew ){
+      *pRc = SQLITE_NOMEM;
+    }else{
+      p->aBuf = aNew;
+      p->nAlloc = nNew;
+    }
+  }
+  return (*pRc!=SQLITE_OK);
+}
+
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append a string to the buffer. All bytes in the string
+** up to (but not including) the nul-terminator are written to the buffer.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendStr(
+  SessionBuffer *p,
+  const char *zStr,
+  int *pRc
+){
+  int nStr = sqlite3Strlen30(zStr);
+  if( 0==sessionBufferGrow(p, nStr+1, pRc) ){
+    memcpy(&p->aBuf[p->nBuf], zStr, nStr);
+    p->nBuf += nStr;
+    p->aBuf[p->nBuf] = 0x00;
+  }
+}
+
+/*
+** Format a string using printf() style formatting and then append it to the
+** buffer using sessionAppendString().
+*/
+static void sessionAppendPrintf(
+  SessionBuffer *p,               /* Buffer to append to */
+  int *pRc,
+  const char *zFmt,
+  ...
+){
+  if( *pRc==SQLITE_OK ){
+    char *zApp = 0;
+    va_list ap;
+    va_start(ap, zFmt);
+    zApp = sqlite3_vmprintf(zFmt, ap);
+    if( zApp==0 ){
+      *pRc = SQLITE_NOMEM;
+    }else{
+      sessionAppendStr(p, zApp, pRc);
+    }
+    va_end(ap);
+    sqlite3_free(zApp);
+  }
+}
+
+/*
+** Prepare a statement against database handle db that SELECTs a single
+** row containing the default values for each column in table pTab. For
+** example, if pTab is declared as:
+**
+**   CREATE TABLE pTab(a PRIMARY KEY, b DEFAULT 123, c DEFAULT 'abcd');
+**
+** Then this function prepares and returns the SQL statement:
+**
+**   SELECT NULL, 123, 'abcd';
+*/
+static int sessionPrepareDfltStmt(
+  sqlite3 *db,                    /* Database handle */
+  SessionTable *pTab,             /* Table to prepare statement for */
+  sqlite3_stmt **ppStmt           /* OUT: Statement handle */
+){
+  SessionBuffer sql = {0,0,0};
+  int rc = SQLITE_OK;
+  const char *zSep = " ";
+  int ii = 0;
+
+  *ppStmt = 0;
+  sessionAppendPrintf(&sql, &rc, "SELECT");
+  for(ii=0; ii<pTab->nCol; ii++){
+    const char *zDflt = pTab->azDflt[ii] ? pTab->azDflt[ii] : "NULL";
+    sessionAppendPrintf(&sql, &rc, "%s%s", zSep, zDflt);
+    zSep = ", ";
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_prepare_v2(db, (const char*)sql.aBuf, -1, ppStmt, 0);
+  }
+  sqlite3_free(sql.aBuf);
+
+  return rc;
+}
+
+/*
+** Table pTab has one or more existing change-records with old.* records
+** with fewer than pTab->nCol columns. This function updates all such
+** change-records with the default values for the missing columns.
+*/
+static int sessionUpdateChanges(sqlite3_session *pSession, SessionTable *pTab){
+  sqlite3_stmt *pStmt = 0;
+  int rc = pSession->rc;
+
+  rc = sessionPrepareDfltStmt(pSession->db, pTab, &pStmt);
+  if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+    int ii = 0;
+    SessionChange **pp = 0;
+    for(ii=0; ii<pTab->nChange; ii++){
+      for(pp=&pTab->apChange[ii]; *pp; pp=&((*pp)->pNext)){
+        if( (*pp)->nRecordField!=pTab->nCol ){
+          sessionUpdateOneChange(pSession, &rc, pp, pTab->nCol, pStmt);
+        }
+      }
+    }
+  }
+
+  pSession->rc = rc;
+  rc = sqlite3_finalize(pStmt);
+  if( pSession->rc==SQLITE_OK ) pSession->rc = rc;
+  return pSession->rc;
+}
+
+/*
+** Versions of the four methods in object SessionHook for use with the
+** sqlite_stat1 table. The purpose of this is to substitute a zero-length
+** blob each time a NULL value is read from the "idx" column of the
+** sqlite_stat1 table.
+*/
+typedef struct SessionStat1Ctx SessionStat1Ctx;
+struct SessionStat1Ctx {
+  SessionHook hook;
+  sqlite3_session *pSession;
+};
+static int sessionStat1Old(void *pCtx, int iCol, sqlite3_value **ppVal){
+  SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
+  sqlite3_value *pVal = 0;
+  int rc = p->hook.xOld(p->hook.pCtx, iCol, &pVal);
+  if( rc==SQLITE_OK && iCol==1 && sqlite3_value_type(pVal)==SQLITE_NULL ){
+    pVal = p->pSession->pZeroBlob;
+  }
+  *ppVal = pVal;
+  return rc;
+}
+static int sessionStat1New(void *pCtx, int iCol, sqlite3_value **ppVal){
+  SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
+  sqlite3_value *pVal = 0;
+  int rc = p->hook.xNew(p->hook.pCtx, iCol, &pVal);
+  if( rc==SQLITE_OK && iCol==1 && sqlite3_value_type(pVal)==SQLITE_NULL ){
+    pVal = p->pSession->pZeroBlob;
+  }
+  *ppVal = pVal;
+  return rc;
+}
+static int sessionStat1Count(void *pCtx){
+  SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
+  return p->hook.xCount(p->hook.pCtx);
+}
+static int sessionStat1Depth(void *pCtx){
+  SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx;
+  return p->hook.xDepth(p->hook.pCtx);
+}
+
+static int sessionUpdateMaxSize(
+  int op,
+  sqlite3_session *pSession,      /* Session object pTab is attached to */
+  SessionTable *pTab,             /* Table that change applies to */
+  SessionChange *pC               /* Update pC->nMaxSize */
+){
+  i64 nNew = 2;
+  if( pC->op==SQLITE_INSERT ){
+    if( pTab->bRowid ) nNew += 9;
+    if( op!=SQLITE_DELETE ){
+      int ii;
+      for(ii=0; ii<pTab->nCol; ii++){
+        sqlite3_value *p = 0;
+        pSession->hook.xNew(pSession->hook.pCtx, pTab->aiIdx[ii], &p);
+        sessionSerializeValue(0, p, &nNew);
+      }
+    }
+  }else if( op==SQLITE_DELETE ){
+    nNew += pC->nRecord;
+    if( sqlite3_preupdate_blobwrite(pSession->db)>=0 ){
+      nNew += pC->nRecord;
+    }
+  }else{
+    int ii;
+    u8 *pCsr = pC->aRecord;
+    if( pTab->bRowid ){
+      nNew += 9 + 1;
+      pCsr += 9;
+    }
+    for(ii=pTab->bRowid; ii<pTab->nCol; ii++){
+      int bChanged = 1;
+      int nOld = 0;
+      int eType;
+      int iIdx = pTab->aiIdx[ii];
+      sqlite3_value *p = 0;
+      pSession->hook.xNew(pSession->hook.pCtx, iIdx, &p);
+      if( p==0 ){
+        return SQLITE_NOMEM;
+      }
+
+      eType = *pCsr++;
+      switch( eType ){
+        case SQLITE_NULL:
+          bChanged = sqlite3_value_type(p)!=SQLITE_NULL;
+          break;
+
+        case SQLITE_FLOAT:
+        case SQLITE_INTEGER: {
+          if( eType==sqlite3_value_type(p) ){
+            sqlite3_int64 iVal = sessionGetI64(pCsr);
+            if( eType==SQLITE_INTEGER ){
+              bChanged = (iVal!=sqlite3_value_int64(p));
+            }else{
+              double dVal;
+              memcpy(&dVal, &iVal, 8);
+              bChanged = (dVal!=sqlite3_value_double(p));
+            }
+          }
+          nOld = 8;
+          pCsr += 8;
+          break;
+        }
+
+        default: {
+          int nByte;
+          nOld = sessionVarintGet(pCsr, &nByte);
+          pCsr += nOld;
+          nOld += nByte;
+          assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
+          if( eType==sqlite3_value_type(p)
+           && nByte==sqlite3_value_bytes(p)
+           && (nByte==0 || 0==memcmp(pCsr, sqlite3_value_blob(p), nByte))
+          ){
+            bChanged = 0;
+          }
+          pCsr += nByte;
+          break;
+        }
+      }
+
+      if( bChanged && pTab->abPK[ii] ){
+        nNew = pC->nRecord + 2;
+        break;
+      }
+
+      if( bChanged ){
+        nNew += 1 + nOld;
+        sessionSerializeValue(0, p, &nNew);
+      }else if( pTab->abPK[ii] ){
+        nNew += 2 + nOld;
+      }else{
+        nNew += 2;
+      }
+    }
+  }
+
+  if( nNew>pC->nMaxSize ){
+    int nIncr = nNew - pC->nMaxSize;
+    pC->nMaxSize = nNew;
+    pSession->nMaxChangesetSize += nIncr;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is only called from with a pre-update-hook reporting a
+** change on table pTab (attached to session pSession). The type of change
+** (UPDATE, INSERT, DELETE) is specified by the first argument.
+**
+** Unless one is already present or an error occurs, an entry is added
+** to the changed-rows hash table associated with table pTab.
+*/
+static void sessionPreupdateOneChange(
+  int op,                         /* One of SQLITE_UPDATE, INSERT, DELETE */
+  i64 iRowid,
+  sqlite3_session *pSession,      /* Session object pTab is attached to */
+  SessionTable *pTab              /* Table that change applies to */
+){
+  int iHash;
+  int bNull = 0;
+  int rc = SQLITE_OK;
+  int nExpect = 0;
+  SessionStat1Ctx stat1 = {{0,0,0,0,0},0};
+
+  if( pSession->rc ) return;
+
+  /* Load table details if required */
+  if( sessionInitTable(pSession, pTab, pSession->db, pSession->zDb) ) return;
+
+  /* Check the number of columns in this xPreUpdate call matches the
+  ** number of columns in the table.  */
+  nExpect = pSession->hook.xCount(pSession->hook.pCtx);
+  if( pTab->nTotalCol<nExpect ){
+    if( sessionReinitTable(pSession, pTab) ) return;
+    if( sessionUpdateChanges(pSession, pTab) ) return;
+  }
+  if( pTab->nTotalCol!=nExpect ){
+    pSession->rc = SQLITE_SCHEMA;
+    return;
+  }
+
+  /* Grow the hash table if required */
+  if( sessionGrowHash(pSession, 0, pTab) ){
+    pSession->rc = SQLITE_NOMEM;
+    return;
+  }
+
+  if( pTab->bStat1 ){
+    stat1.hook = pSession->hook;
+    stat1.pSession = pSession;
+    pSession->hook.pCtx = (void*)&stat1;
+    pSession->hook.xNew = sessionStat1New;
+    pSession->hook.xOld = sessionStat1Old;
+    pSession->hook.xCount = sessionStat1Count;
+    pSession->hook.xDepth = sessionStat1Depth;
+    if( pSession->pZeroBlob==0 ){
+      sqlite3_value *p = sqlite3ValueNew(0);
+      if( p==0 ){
+        rc = SQLITE_NOMEM;
+        goto error_out;
+      }
+      sqlite3ValueSetStr(p, 0, "", 0, SQLITE_STATIC);
+      pSession->pZeroBlob = p;
+    }
+  }
+
+  /* Calculate the hash-key for this change. If the primary key of the row
+  ** includes a NULL value, exit early. Such changes are ignored by the
+  ** session module. */
+  rc = sessionPreupdateHash(
+      pSession, iRowid, pTab, op==SQLITE_INSERT, &iHash, &bNull
+  );
+  if( rc!=SQLITE_OK ) goto error_out;
+
+  if( bNull==0 ){
+    /* Search the hash table for an existing record for this row. */
+    SessionChange *pC;
+    for(pC=pTab->apChange[iHash]; pC; pC=pC->pNext){
+      if( sessionPreupdateEqual(pSession, iRowid, pTab, pC, op) ) break;
+    }
+
+    if( pC==0 ){
+      /* Create a new change object containing all the old values (if
+      ** this is an SQLITE_UPDATE or SQLITE_DELETE), or just the PK
+      ** values (if this is an INSERT). */
+      sqlite3_int64 nByte;    /* Number of bytes to allocate */
+      int i;                  /* Used to iterate through columns */
+
+      assert( rc==SQLITE_OK );
+      pTab->nEntry++;
+
+      /* Figure out how large an allocation is required */
+      nByte = sizeof(SessionChange);
+      for(i=pTab->bRowid; i<pTab->nCol; i++){
+        int iIdx = pTab->aiIdx[i];
+        sqlite3_value *p = 0;
+        if( op!=SQLITE_INSERT ){
+          /* This may fail if the column has a non-NULL default and was added
+          ** using ALTER TABLE ADD COLUMN after this record was created. */
+          rc = pSession->hook.xOld(pSession->hook.pCtx, iIdx, &p);
+        }else if( pTab->abPK[i] ){
+          TESTONLY(int trc = ) pSession->hook.xNew(pSession->hook.pCtx,iIdx,&p);
+          assert( trc==SQLITE_OK );
+        }
+
+        if( rc==SQLITE_OK ){
+          /* This may fail if SQLite value p contains a utf-16 string that must
+          ** be converted to utf-8 and an OOM error occurs while doing so. */
+          rc = sessionSerializeValue(0, p, &nByte);
+        }
+        if( rc!=SQLITE_OK ) goto error_out;
+      }
+      if( pTab->bRowid ){
+        nByte += 9;               /* Size of rowid field - an integer */
+      }
+
+      /* Allocate the change object */
+      pC = (SessionChange*)sessionMalloc64(pSession, nByte);
+      if( !pC ){
+        rc = SQLITE_NOMEM;
+        goto error_out;
+      }else{
+        memset(pC, 0, sizeof(SessionChange));
+        pC->aRecord = (u8 *)&pC[1];
+      }
+
+      /* Populate the change object. None of the preupdate_old(),
+      ** preupdate_new() or SerializeValue() calls below may fail as all
+      ** required values and encodings have already been cached in memory.
+      ** It is not possible for an OOM to occur in this block. */
+      nByte = 0;
+      if( pTab->bRowid ){
+        pC->aRecord[0] = SQLITE_INTEGER;
+        sessionPutI64(&pC->aRecord[1], iRowid);
+        nByte = 9;
+      }
+      for(i=pTab->bRowid; i<pTab->nCol; i++){
+        sqlite3_value *p = 0;
+        int iIdx = pTab->aiIdx[i];
+        if( op!=SQLITE_INSERT ){
+          pSession->hook.xOld(pSession->hook.pCtx, iIdx, &p);
+        }else if( pTab->abPK[i] ){
+          pSession->hook.xNew(pSession->hook.pCtx, iIdx, &p);
+        }
+        sessionSerializeValue(&pC->aRecord[nByte], p, &nByte);
+      }
+
+      /* Add the change to the hash-table */
+      if( pSession->bIndirect || pSession->hook.xDepth(pSession->hook.pCtx) ){
+        pC->bIndirect = 1;
+      }
+      pC->nRecordField = pTab->nCol;
+      pC->nRecord = nByte;
+      pC->op = op;
+      pC->pNext = pTab->apChange[iHash];
+      pTab->apChange[iHash] = pC;
+
+    }else if( pC->bIndirect ){
+      /* If the existing change is considered "indirect", but this current
+      ** change is "direct", mark the change object as direct. */
+      if( pSession->hook.xDepth(pSession->hook.pCtx)==0
+       && pSession->bIndirect==0
+      ){
+        pC->bIndirect = 0;
+      }
+    }
+
+    assert( rc==SQLITE_OK );
+    if( pSession->bEnableSize ){
+      rc = sessionUpdateMaxSize(op, pSession, pTab, pC);
+    }
+  }
+
+
+  /* If an error has occurred, mark the session object as failed. */
+ error_out:
+  if( pTab->bStat1 ){
+    pSession->hook = stat1.hook;
+  }
+  if( rc!=SQLITE_OK ){
+    pSession->rc = rc;
+  }
+}
+
+static int sessionFindTable(
+  sqlite3_session *pSession,
+  const char *zName,
+  SessionTable **ppTab
+){
+  int rc = SQLITE_OK;
+  int nName = sqlite3Strlen30(zName);
+  SessionTable *pRet;
+
+  /* Search for an existing table */
+  for(pRet=pSession->pTable; pRet; pRet=pRet->pNext){
+    if( 0==sqlite3_strnicmp(pRet->zName, zName, nName+1) ) break;
+  }
+
+  if( pRet==0 && pSession->bAutoAttach ){
+    /* If there is a table-filter configured, invoke it. If it returns 0,
+    ** do not automatically add the new table. */
+    if( pSession->xTableFilter==0
+     || pSession->xTableFilter(pSession->pFilterCtx, zName)
+    ){
+      rc = sqlite3session_attach(pSession, zName);
+      if( rc==SQLITE_OK ){
+        pRet = pSession->pTable;
+        while( ALWAYS(pRet) && pRet->pNext ){
+          pRet = pRet->pNext;
+        }
+        assert( pRet!=0 );
+        assert( 0==sqlite3_strnicmp(pRet->zName, zName, nName+1) );
+      }
+    }
+  }
+
+  assert( rc==SQLITE_OK || pRet==0 );
+  *ppTab = pRet;
+  return rc;
+}
+
+/*
+** The 'pre-update' hook registered by this module with SQLite databases.
+*/
+static void xPreUpdate(
+  void *pCtx,                     /* Copy of third arg to preupdate_hook() */
+  sqlite3 *db,                    /* Database handle */
+  int op,                         /* SQLITE_UPDATE, DELETE or INSERT */
+  char const *zDb,                /* Database name */
+  char const *zName,              /* Table name */
+  sqlite3_int64 iKey1,            /* Rowid of row about to be deleted/updated */
+  sqlite3_int64 iKey2             /* New rowid value (for a rowid UPDATE) */
+){
+  sqlite3_session *pSession;
+  int nDb = sqlite3Strlen30(zDb);
+
+  assert( sqlite3_mutex_held(db->mutex) );
+  (void)iKey1;
+  (void)iKey2;
+
+  for(pSession=(sqlite3_session *)pCtx; pSession; pSession=pSession->pNext){
+    SessionTable *pTab;
+
+    /* If this session is attached to a different database ("main", "temp"
+    ** etc.), or if it is not currently enabled, there is nothing to do. Skip
+    ** to the next session object attached to this database. */
+    if( pSession->bEnable==0 ) continue;
+    if( pSession->rc ) continue;
+    if( sqlite3_strnicmp(zDb, pSession->zDb, nDb+1) ) continue;
+
+    pSession->rc = sessionFindTable(pSession, zName, &pTab);
+    if( pTab ){
+      assert( pSession->rc==SQLITE_OK );
+      assert( op==SQLITE_UPDATE || iKey1==iKey2 );
+      sessionPreupdateOneChange(op, iKey1, pSession, pTab);
+      if( op==SQLITE_UPDATE ){
+        sessionPreupdateOneChange(SQLITE_INSERT, iKey2, pSession, pTab);
+      }
+    }
+  }
+}
+
+/*
+** The pre-update hook implementations.
+*/
+static int sessionPreupdateOld(void *pCtx, int iVal, sqlite3_value **ppVal){
+  return sqlite3_preupdate_old((sqlite3*)pCtx, iVal, ppVal);
+}
+static int sessionPreupdateNew(void *pCtx, int iVal, sqlite3_value **ppVal){
+  return sqlite3_preupdate_new((sqlite3*)pCtx, iVal, ppVal);
+}
+static int sessionPreupdateCount(void *pCtx){
+  return sqlite3_preupdate_count((sqlite3*)pCtx);
+}
+static int sessionPreupdateDepth(void *pCtx){
+  return sqlite3_preupdate_depth((sqlite3*)pCtx);
+}
+
+/*
+** Install the pre-update hooks on the session object passed as the only
+** argument.
+*/
+static void sessionPreupdateHooks(
+  sqlite3_session *pSession
+){
+  pSession->hook.pCtx = (void*)pSession->db;
+  pSession->hook.xOld = sessionPreupdateOld;
+  pSession->hook.xNew = sessionPreupdateNew;
+  pSession->hook.xCount = sessionPreupdateCount;
+  pSession->hook.xDepth = sessionPreupdateDepth;
+}
+
+typedef struct SessionDiffCtx SessionDiffCtx;
+struct SessionDiffCtx {
+  sqlite3_stmt *pStmt;
+  int bRowid;
+  int nOldOff;
+};
+
+/*
+** The diff hook implementations.
+*/
+static int sessionDiffOld(void *pCtx, int iVal, sqlite3_value **ppVal){
+  SessionDiffCtx *p = (SessionDiffCtx*)pCtx;
+  *ppVal = sqlite3_column_value(p->pStmt, iVal+p->nOldOff+p->bRowid);
+  return SQLITE_OK;
+}
+static int sessionDiffNew(void *pCtx, int iVal, sqlite3_value **ppVal){
+  SessionDiffCtx *p = (SessionDiffCtx*)pCtx;
+  *ppVal = sqlite3_column_value(p->pStmt, iVal+p->bRowid);
+   return SQLITE_OK;
+}
+static int sessionDiffCount(void *pCtx){
+  SessionDiffCtx *p = (SessionDiffCtx*)pCtx;
+  return (p->nOldOff ? p->nOldOff : sqlite3_column_count(p->pStmt)) - p->bRowid;
+}
+static int sessionDiffDepth(void *pCtx){
+  (void)pCtx;
+  return 0;
+}
+
+/*
+** Install the diff hooks on the session object passed as the only
+** argument.
+*/
+static void sessionDiffHooks(
+  sqlite3_session *pSession,
+  SessionDiffCtx *pDiffCtx
+){
+  pSession->hook.pCtx = (void*)pDiffCtx;
+  pSession->hook.xOld = sessionDiffOld;
+  pSession->hook.xNew = sessionDiffNew;
+  pSession->hook.xCount = sessionDiffCount;
+  pSession->hook.xDepth = sessionDiffDepth;
+}
+
+static char *sessionExprComparePK(
+  int nCol,
+  const char *zDb1, const char *zDb2,
+  const char *zTab,
+  const char **azCol, u8 *abPK
+){
+  int i;
+  const char *zSep = "";
+  char *zRet = 0;
+
+  for(i=0; i<nCol; i++){
+    if( abPK[i] ){
+      zRet = sqlite3_mprintf("%z%s\"%w\".\"%w\".\"%w\"=\"%w\".\"%w\".\"%w\"",
+          zRet, zSep, zDb1, zTab, azCol[i], zDb2, zTab, azCol[i]
+      );
+      zSep = " AND ";
+      if( zRet==0 ) break;
+    }
+  }
+
+  return zRet;
+}
+
+static char *sessionExprCompareOther(
+  int nCol,
+  const char *zDb1, const char *zDb2,
+  const char *zTab,
+  const char **azCol, u8 *abPK
+){
+  int i;
+  const char *zSep = "";
+  char *zRet = 0;
+  int bHave = 0;
+
+  for(i=0; i<nCol; i++){
+    if( abPK[i]==0 ){
+      bHave = 1;
+      zRet = sqlite3_mprintf(
+          "%z%s\"%w\".\"%w\".\"%w\" IS NOT \"%w\".\"%w\".\"%w\"",
+          zRet, zSep, zDb1, zTab, azCol[i], zDb2, zTab, azCol[i]
+      );
+      zSep = " OR ";
+      if( zRet==0 ) break;
+    }
+  }
+
+  if( bHave==0 ){
+    assert( zRet==0 );
+    zRet = sqlite3_mprintf("0");
+  }
+
+  return zRet;
+}
+
+static char *sessionSelectFindNew(
+  const char *zDb1,      /* Pick rows in this db only */
+  const char *zDb2,      /* But not in this one */
+  int bRowid,
+  const char *zTbl,      /* Table name */
+  const char *zExpr
+){
+  const char *zSel = (bRowid ? SESSIONS_ROWID ", *" : "*");
+  char *zRet = sqlite3_mprintf(
+      "SELECT %s FROM \"%w\".\"%w\" WHERE NOT EXISTS ("
+      "  SELECT 1 FROM \"%w\".\"%w\" WHERE %s"
+      ")",
+      zSel, zDb1, zTbl, zDb2, zTbl, zExpr
+  );
+  return zRet;
+}
+
+static int sessionDiffFindNew(
+  int op,
+  sqlite3_session *pSession,
+  SessionTable *pTab,
+  const char *zDb1,
+  const char *zDb2,
+  char *zExpr
+){
+  int rc = SQLITE_OK;
+  char *zStmt = sessionSelectFindNew(
+      zDb1, zDb2, pTab->bRowid, pTab->zName, zExpr
+  );
+
+  if( zStmt==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_stmt *pStmt;
+    rc = sqlite3_prepare(pSession->db, zStmt, -1, &pStmt, 0);
+    if( rc==SQLITE_OK ){
+      SessionDiffCtx *pDiffCtx = (SessionDiffCtx*)pSession->hook.pCtx;
+      pDiffCtx->pStmt = pStmt;
+      pDiffCtx->nOldOff = 0;
+      pDiffCtx->bRowid = pTab->bRowid;
+      while( SQLITE_ROW==sqlite3_step(pStmt) ){
+        i64 iRowid = (pTab->bRowid ? sqlite3_column_int64(pStmt, 0) : 0);
+        sessionPreupdateOneChange(op, iRowid, pSession, pTab);
+      }
+      rc = sqlite3_finalize(pStmt);
+    }
+    sqlite3_free(zStmt);
+  }
+
+  return rc;
+}
+
+/*
+** Return a comma-separated list of the fully-qualified (with both database
+** and table name) column names from table pTab. e.g.
+**
+**    "main"."t1"."a", "main"."t1"."b", "main"."t1"."c"
+*/
+static char *sessionAllCols(
+  const char *zDb,
+  SessionTable *pTab
+){
+  int ii;
+  char *zRet = 0;
+  for(ii=0; ii<pTab->nCol; ii++){
+    zRet = sqlite3_mprintf("%z%s\"%w\".\"%w\".\"%w\"",
+        zRet, (zRet ? ", " : ""), zDb, pTab->zName, pTab->azCol[ii]
+    );
+    if( !zRet ) break;
+  }
+  return zRet;
+}
+
+static int sessionDiffFindModified(
+  sqlite3_session *pSession,
+  SessionTable *pTab,
+  const char *zFrom,
+  const char *zExpr
+){
+  int rc = SQLITE_OK;
+
+  char *zExpr2 = sessionExprCompareOther(pTab->nCol,
+      pSession->zDb, zFrom, pTab->zName, pTab->azCol, pTab->abPK
+  );
+  if( zExpr2==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    char *z1 = sessionAllCols(pSession->zDb, pTab);
+    char *z2 = sessionAllCols(zFrom, pTab);
+    char *zStmt = sqlite3_mprintf(
+        "SELECT %s,%s FROM \"%w\".\"%w\", \"%w\".\"%w\" WHERE %s AND (%z)",
+        z1, z2, pSession->zDb, pTab->zName, zFrom, pTab->zName, zExpr, zExpr2
+    );
+    if( zStmt==0 || z1==0 || z2==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      sqlite3_stmt *pStmt;
+      rc = sqlite3_prepare(pSession->db, zStmt, -1, &pStmt, 0);
+
+      if( rc==SQLITE_OK ){
+        SessionDiffCtx *pDiffCtx = (SessionDiffCtx*)pSession->hook.pCtx;
+        pDiffCtx->pStmt = pStmt;
+        pDiffCtx->nOldOff = pTab->nCol;
+        while( SQLITE_ROW==sqlite3_step(pStmt) ){
+          i64 iRowid = (pTab->bRowid ? sqlite3_column_int64(pStmt, 0) : 0);
+          sessionPreupdateOneChange(SQLITE_UPDATE, iRowid, pSession, pTab);
+        }
+        rc = sqlite3_finalize(pStmt);
+      }
+    }
+    sqlite3_free(zStmt);
+    sqlite3_free(z1);
+    sqlite3_free(z2);
+  }
+
+  return rc;
+}
+
+SQLITE_API int sqlite3session_diff(
+  sqlite3_session *pSession,
+  const char *zFrom,
+  const char *zTbl,
+  char **pzErrMsg
+){
+  const char *zDb = pSession->zDb;
+  int rc = pSession->rc;
+  SessionDiffCtx d;
+
+  memset(&d, 0, sizeof(d));
+  sessionDiffHooks(pSession, &d);
+
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+  if( pzErrMsg ) *pzErrMsg = 0;
+  if( rc==SQLITE_OK ){
+    char *zExpr = 0;
+    sqlite3 *db = pSession->db;
+    SessionTable *pTo;            /* Table zTbl */
+
+    /* Locate and if necessary initialize the target table object */
+    rc = sessionFindTable(pSession, zTbl, &pTo);
+    if( pTo==0 ) goto diff_out;
+    if( sessionInitTable(pSession, pTo, pSession->db, pSession->zDb) ){
+      rc = pSession->rc;
+      goto diff_out;
+    }
+
+    /* Check the table schemas match */
+    if( rc==SQLITE_OK ){
+      int bHasPk = 0;
+      int bMismatch = 0;
+      int nCol;                   /* Columns in zFrom.zTbl */
+      int bRowid = 0;
+      u8 *abPK;
+      const char **azCol = 0;
+      rc = sessionTableInfo(0, db, zFrom, zTbl,
+          &nCol, 0, 0, &azCol, 0, 0, &abPK,
+          pSession->bImplicitPK ? &bRowid : 0
+      );
+      if( rc==SQLITE_OK ){
+        if( pTo->nCol!=nCol ){
+          bMismatch = 1;
+        }else{
+          int i;
+          for(i=0; i<nCol; i++){
+            if( pTo->abPK[i]!=abPK[i] ) bMismatch = 1;
+            if( sqlite3_stricmp(azCol[i], pTo->azCol[i]) ) bMismatch = 1;
+            if( abPK[i] ) bHasPk = 1;
+          }
+        }
+      }
+      sqlite3_free((char*)azCol);
+      if( bMismatch ){
+        if( pzErrMsg ){
+          *pzErrMsg = sqlite3_mprintf("table schemas do not match");
+        }
+        rc = SQLITE_SCHEMA;
+      }
+      if( bHasPk==0 ){
+        /* Ignore tables with no primary keys */
+        goto diff_out;
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      zExpr = sessionExprComparePK(pTo->nCol,
+          zDb, zFrom, pTo->zName, pTo->azCol, pTo->abPK
+      );
+    }
+
+    /* Find new rows */
+    if( rc==SQLITE_OK ){
+      rc = sessionDiffFindNew(SQLITE_INSERT, pSession, pTo, zDb, zFrom, zExpr);
+    }
+
+    /* Find old rows */
+    if( rc==SQLITE_OK ){
+      rc = sessionDiffFindNew(SQLITE_DELETE, pSession, pTo, zFrom, zDb, zExpr);
+    }
+
+    /* Find modified rows */
+    if( rc==SQLITE_OK ){
+      rc = sessionDiffFindModified(pSession, pTo, zFrom, zExpr);
+    }
+
+    sqlite3_free(zExpr);
+  }
+
+ diff_out:
+  sessionPreupdateHooks(pSession);
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+  return rc;
+}
+
+/*
+** Create a session object. This session object will record changes to
+** database zDb attached to connection db.
+*/
+SQLITE_API int sqlite3session_create(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of db (e.g. "main") */
+  sqlite3_session **ppSession     /* OUT: New session object */
+){
+  sqlite3_session *pNew;          /* Newly allocated session object */
+  sqlite3_session *pOld;          /* Session object already attached to db */
+  int nDb = sqlite3Strlen30(zDb); /* Length of zDb in bytes */
+
+  /* Zero the output value in case an error occurs. */
+  *ppSession = 0;
+
+  /* Allocate and populate the new session object. */
+  pNew = (sqlite3_session *)sqlite3_malloc64(sizeof(sqlite3_session) + nDb + 1);
+  if( !pNew ) return SQLITE_NOMEM;
+  memset(pNew, 0, sizeof(sqlite3_session));
+  pNew->db = db;
+  pNew->zDb = (char *)&pNew[1];
+  pNew->bEnable = 1;
+  memcpy(pNew->zDb, zDb, nDb+1);
+  sessionPreupdateHooks(pNew);
+
+  /* Add the new session object to the linked list of session objects
+  ** attached to database handle $db. Do this under the cover of the db
+  ** handle mutex.  */
+  sqlite3_mutex_enter(sqlite3_db_mutex(db));
+  pOld = (sqlite3_session*)sqlite3_preupdate_hook(db, xPreUpdate, (void*)pNew);
+  pNew->pNext = pOld;
+  sqlite3_mutex_leave(sqlite3_db_mutex(db));
+
+  *ppSession = pNew;
+  return SQLITE_OK;
+}
+
+/*
+** Free the list of table objects passed as the first argument. The contents
+** of the changed-rows hash tables are also deleted.
+*/
+static void sessionDeleteTable(sqlite3_session *pSession, SessionTable *pList){
+  SessionTable *pNext;
+  SessionTable *pTab;
+
+  for(pTab=pList; pTab; pTab=pNext){
+    int i;
+    pNext = pTab->pNext;
+    for(i=0; i<pTab->nChange; i++){
+      SessionChange *p;
+      SessionChange *pNextChange;
+      for(p=pTab->apChange[i]; p; p=pNextChange){
+        pNextChange = p->pNext;
+        sessionFree(pSession, p);
+      }
+    }
+    sqlite3_finalize(pTab->pDfltStmt);
+    sessionFree(pSession, (char*)pTab->azCol);  /* cast works around VC++ bug */
+    sessionFree(pSession, pTab->apChange);
+    sessionFree(pSession, pTab);
+  }
+}
+
+/*
+** Delete a session object previously allocated using sqlite3session_create().
+*/
+SQLITE_API void sqlite3session_delete(sqlite3_session *pSession){
+  sqlite3 *db = pSession->db;
+  sqlite3_session *pHead;
+  sqlite3_session **pp;
+
+  /* Unlink the session from the linked list of sessions attached to the
+  ** database handle. Hold the db mutex while doing so.  */
+  sqlite3_mutex_enter(sqlite3_db_mutex(db));
+  pHead = (sqlite3_session*)sqlite3_preupdate_hook(db, 0, 0);
+  for(pp=&pHead; ALWAYS((*pp)!=0); pp=&((*pp)->pNext)){
+    if( (*pp)==pSession ){
+      *pp = (*pp)->pNext;
+      if( pHead ) sqlite3_preupdate_hook(db, xPreUpdate, (void*)pHead);
+      break;
+    }
+  }
+  sqlite3_mutex_leave(sqlite3_db_mutex(db));
+  sqlite3ValueFree(pSession->pZeroBlob);
+
+  /* Delete all attached table objects. And the contents of their
+  ** associated hash-tables. */
+  sessionDeleteTable(pSession, pSession->pTable);
+
+  /* Free the session object. */
+  sqlite3_free(pSession);
+}
+
+/*
+** Set a table filter on a Session Object.
+*/
+SQLITE_API void sqlite3session_table_filter(
+  sqlite3_session *pSession,
+  int(*xFilter)(void*, const char*),
+  void *pCtx                      /* First argument passed to xFilter */
+){
+  pSession->bAutoAttach = 1;
+  pSession->pFilterCtx = pCtx;
+  pSession->xTableFilter = xFilter;
+}
+
+/*
+** Attach a table to a session. All subsequent changes made to the table
+** while the session object is enabled will be recorded.
+**
+** Only tables that have a PRIMARY KEY defined may be attached. It does
+** not matter if the PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias)
+** or not.
+*/
+SQLITE_API int sqlite3session_attach(
+  sqlite3_session *pSession,      /* Session object */
+  const char *zName               /* Table name */
+){
+  int rc = SQLITE_OK;
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+
+  if( !zName ){
+    pSession->bAutoAttach = 1;
+  }else{
+    SessionTable *pTab;           /* New table object (if required) */
+    int nName;                    /* Number of bytes in string zName */
+
+    /* First search for an existing entry. If one is found, this call is
+    ** a no-op. Return early. */
+    nName = sqlite3Strlen30(zName);
+    for(pTab=pSession->pTable; pTab; pTab=pTab->pNext){
+      if( 0==sqlite3_strnicmp(pTab->zName, zName, nName+1) ) break;
+    }
+
+    if( !pTab ){
+      /* Allocate new SessionTable object. */
+      int nByte = sizeof(SessionTable) + nName + 1;
+      pTab = (SessionTable*)sessionMalloc64(pSession, nByte);
+      if( !pTab ){
+        rc = SQLITE_NOMEM;
+      }else{
+        /* Populate the new SessionTable object and link it into the list.
+        ** The new object must be linked onto the end of the list, not
+        ** simply added to the start of it in order to ensure that tables
+        ** appear in the correct order when a changeset or patchset is
+        ** eventually generated. */
+        SessionTable **ppTab;
+        memset(pTab, 0, sizeof(SessionTable));
+        pTab->zName = (char *)&pTab[1];
+        memcpy(pTab->zName, zName, nName+1);
+        for(ppTab=&pSession->pTable; *ppTab; ppTab=&(*ppTab)->pNext);
+        *ppTab = pTab;
+      }
+    }
+  }
+
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+  return rc;
+}
+
+/*
+** Append the value passed as the second argument to the buffer passed
+** as the first.
+**
+** This function is a no-op if *pRc is non-zero when it is called.
+** Otherwise, if an error occurs, *pRc is set to an SQLite error code
+** before returning.
+*/
+static void sessionAppendValue(SessionBuffer *p, sqlite3_value *pVal, int *pRc){
+  int rc = *pRc;
+  if( rc==SQLITE_OK ){
+    sqlite3_int64 nByte = 0;
+    rc = sessionSerializeValue(0, pVal, &nByte);
+    sessionBufferGrow(p, nByte, &rc);
+    if( rc==SQLITE_OK ){
+      rc = sessionSerializeValue(&p->aBuf[p->nBuf], pVal, 0);
+      p->nBuf += nByte;
+    }else{
+      *pRc = rc;
+    }
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append a single byte to the buffer.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendByte(SessionBuffer *p, u8 v, int *pRc){
+  if( 0==sessionBufferGrow(p, 1, pRc) ){
+    p->aBuf[p->nBuf++] = v;
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append a single varint to the buffer.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendVarint(SessionBuffer *p, int v, int *pRc){
+  if( 0==sessionBufferGrow(p, 9, pRc) ){
+    p->nBuf += sessionVarintPut(&p->aBuf[p->nBuf], v);
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append a blob of data to the buffer.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendBlob(
+  SessionBuffer *p,
+  const u8 *aBlob,
+  int nBlob,
+  int *pRc
+){
+  if( nBlob>0 && 0==sessionBufferGrow(p, nBlob, pRc) ){
+    memcpy(&p->aBuf[p->nBuf], aBlob, nBlob);
+    p->nBuf += nBlob;
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append the string representation of integer iVal
+** to the buffer. No nul-terminator is written.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendInteger(
+  SessionBuffer *p,               /* Buffer to append to */
+  int iVal,                       /* Value to write the string rep. of */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  char aBuf[24];
+  sqlite3_snprintf(sizeof(aBuf)-1, aBuf, "%d", iVal);
+  sessionAppendStr(p, aBuf, pRc);
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwise, append the string zStr enclosed in quotes (") and
+** with any embedded quote characters escaped to the buffer. No
+** nul-terminator byte is written.
+**
+** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before
+** returning.
+*/
+static void sessionAppendIdent(
+  SessionBuffer *p,               /* Buffer to a append to */
+  const char *zStr,               /* String to quote, escape and append */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  int nStr = sqlite3Strlen30(zStr)*2 + 2 + 2;
+  if( 0==sessionBufferGrow(p, nStr, pRc) ){
+    char *zOut = (char *)&p->aBuf[p->nBuf];
+    const char *zIn = zStr;
+    *zOut++ = '"';
+    if( zIn!=0 ){
+      while( *zIn ){
+        if( *zIn=='"' ) *zOut++ = '"';
+        *zOut++ = *(zIn++);
+      }
+    }
+    *zOut++ = '"';
+    p->nBuf = (int)((u8 *)zOut - p->aBuf);
+    p->aBuf[p->nBuf] = 0x00;
+  }
+}
+
+/*
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. Otherwse, it appends the serialized version of the value stored
+** in column iCol of the row that SQL statement pStmt currently points
+** to to the buffer.
+*/
+static void sessionAppendCol(
+  SessionBuffer *p,               /* Buffer to append to */
+  sqlite3_stmt *pStmt,            /* Handle pointing to row containing value */
+  int iCol,                       /* Column to read value from */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  if( *pRc==SQLITE_OK ){
+    int eType = sqlite3_column_type(pStmt, iCol);
+    sessionAppendByte(p, (u8)eType, pRc);
+    if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+      sqlite3_int64 i;
+      u8 aBuf[8];
+      if( eType==SQLITE_INTEGER ){
+        i = sqlite3_column_int64(pStmt, iCol);
+      }else{
+        double r = sqlite3_column_double(pStmt, iCol);
+        memcpy(&i, &r, 8);
+      }
+      sessionPutI64(aBuf, i);
+      sessionAppendBlob(p, aBuf, 8, pRc);
+    }
+    if( eType==SQLITE_BLOB || eType==SQLITE_TEXT ){
+      u8 *z;
+      int nByte;
+      if( eType==SQLITE_BLOB ){
+        z = (u8 *)sqlite3_column_blob(pStmt, iCol);
+      }else{
+        z = (u8 *)sqlite3_column_text(pStmt, iCol);
+      }
+      nByte = sqlite3_column_bytes(pStmt, iCol);
+      if( z || (eType==SQLITE_BLOB && nByte==0) ){
+        sessionAppendVarint(p, nByte, pRc);
+        sessionAppendBlob(p, z, nByte, pRc);
+      }else{
+        *pRc = SQLITE_NOMEM;
+      }
+    }
+  }
+}
+
+/*
+**
+** This function appends an update change to the buffer (see the comments
+** under "CHANGESET FORMAT" at the top of the file). An update change
+** consists of:
+**
+**   1 byte:  SQLITE_UPDATE (0x17)
+**   n bytes: old.* record (see RECORD FORMAT)
+**   m bytes: new.* record (see RECORD FORMAT)
+**
+** The SessionChange object passed as the third argument contains the
+** values that were stored in the row when the session began (the old.*
+** values). The statement handle passed as the second argument points
+** at the current version of the row (the new.* values).
+**
+** If all of the old.* values are equal to their corresponding new.* value
+** (i.e. nothing has changed), then no data at all is appended to the buffer.
+**
+** Otherwise, the old.* record contains all primary key values and the
+** original values of any fields that have been modified. The new.* record
+** contains the new values of only those fields that have been modified.
+*/
+static int sessionAppendUpdate(
+  SessionBuffer *pBuf,            /* Buffer to append to */
+  int bPatchset,                  /* True for "patchset", 0 for "changeset" */
+  sqlite3_stmt *pStmt,            /* Statement handle pointing at new row */
+  SessionChange *p,               /* Object containing old values */
+  u8 *abPK                        /* Boolean array - true for PK columns */
+){
+  int rc = SQLITE_OK;
+  SessionBuffer buf2 = {0,0,0}; /* Buffer to accumulate new.* record in */
+  int bNoop = 1;                /* Set to zero if any values are modified */
+  int nRewind = pBuf->nBuf;     /* Set to zero if any values are modified */
+  int i;                        /* Used to iterate through columns */
+  u8 *pCsr = p->aRecord;        /* Used to iterate through old.* values */
+
+  assert( abPK!=0 );
+  sessionAppendByte(pBuf, SQLITE_UPDATE, &rc);
+  sessionAppendByte(pBuf, p->bIndirect, &rc);
+  for(i=0; i<sqlite3_column_count(pStmt); i++){
+    int bChanged = 0;
+    int nAdvance;
+    int eType = *pCsr;
+    switch( eType ){
+      case SQLITE_NULL:
+        nAdvance = 1;
+        if( sqlite3_column_type(pStmt, i)!=SQLITE_NULL ){
+          bChanged = 1;
+        }
+        break;
+
+      case SQLITE_FLOAT:
+      case SQLITE_INTEGER: {
+        nAdvance = 9;
+        if( eType==sqlite3_column_type(pStmt, i) ){
+          sqlite3_int64 iVal = sessionGetI64(&pCsr[1]);
+          if( eType==SQLITE_INTEGER ){
+            if( iVal==sqlite3_column_int64(pStmt, i) ) break;
+          }else{
+            double dVal;
+            memcpy(&dVal, &iVal, 8);
+            if( dVal==sqlite3_column_double(pStmt, i) ) break;
+          }
+        }
+        bChanged = 1;
+        break;
+      }
+
+      default: {
+        int n;
+        int nHdr = 1 + sessionVarintGet(&pCsr[1], &n);
+        assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
+        nAdvance = nHdr + n;
+        if( eType==sqlite3_column_type(pStmt, i)
+         && n==sqlite3_column_bytes(pStmt, i)
+         && (n==0 || 0==memcmp(&pCsr[nHdr], sqlite3_column_blob(pStmt, i), n))
+        ){
+          break;
+        }
+        bChanged = 1;
+      }
+    }
+
+    /* If at least one field has been modified, this is not a no-op. */
+    if( bChanged ) bNoop = 0;
+
+    /* Add a field to the old.* record. This is omitted if this module is
+    ** currently generating a patchset. */
+    if( bPatchset==0 ){
+      if( bChanged || abPK[i] ){
+        sessionAppendBlob(pBuf, pCsr, nAdvance, &rc);
+      }else{
+        sessionAppendByte(pBuf, 0, &rc);
+      }
+    }
+
+    /* Add a field to the new.* record. Or the only record if currently
+    ** generating a patchset.  */
+    if( bChanged || (bPatchset && abPK[i]) ){
+      sessionAppendCol(&buf2, pStmt, i, &rc);
+    }else{
+      sessionAppendByte(&buf2, 0, &rc);
+    }
+
+    pCsr += nAdvance;
+  }
+
+  if( bNoop ){
+    pBuf->nBuf = nRewind;
+  }else{
+    sessionAppendBlob(pBuf, buf2.aBuf, buf2.nBuf, &rc);
+  }
+  sqlite3_free(buf2.aBuf);
+
+  return rc;
+}
+
+/*
+** Append a DELETE change to the buffer passed as the first argument. Use
+** the changeset format if argument bPatchset is zero, or the patchset
+** format otherwise.
+*/
+static int sessionAppendDelete(
+  SessionBuffer *pBuf,            /* Buffer to append to */
+  int bPatchset,                  /* True for "patchset", 0 for "changeset" */
+  SessionChange *p,               /* Object containing old values */
+  int nCol,                       /* Number of columns in table */
+  u8 *abPK                        /* Boolean array - true for PK columns */
+){
+  int rc = SQLITE_OK;
+
+  sessionAppendByte(pBuf, SQLITE_DELETE, &rc);
+  sessionAppendByte(pBuf, p->bIndirect, &rc);
+
+  if( bPatchset==0 ){
+    sessionAppendBlob(pBuf, p->aRecord, p->nRecord, &rc);
+  }else{
+    int i;
+    u8 *a = p->aRecord;
+    for(i=0; i<nCol; i++){
+      u8 *pStart = a;
+      int eType = *a++;
+
+      switch( eType ){
+        case 0:
+        case SQLITE_NULL:
+          assert( abPK[i]==0 );
+          break;
+
+        case SQLITE_FLOAT:
+        case SQLITE_INTEGER:
+          a += 8;
+          break;
+
+        default: {
+          int n;
+          a += sessionVarintGet(a, &n);
+          a += n;
+          break;
+        }
+      }
+      if( abPK[i] ){
+        sessionAppendBlob(pBuf, pStart, (int)(a-pStart), &rc);
+      }
+    }
+    assert( (a - p->aRecord)==p->nRecord );
+  }
+
+  return rc;
+}
+
+/*
+** Formulate and prepare a SELECT statement to retrieve a row from table
+** zTab in database zDb based on its primary key. i.e.
+**
+**   SELECT *, <noop-test> FROM zDb.zTab WHERE (pk1, pk2,...) IS (?1, ?2,...)
+**
+** where <noop-test> is:
+**
+**   1 AND (?A OR ?1 IS <column>) AND ...
+**
+** for each non-pk <column>.
+*/
+static int sessionSelectStmt(
+  sqlite3 *db,                    /* Database handle */
+  int bIgnoreNoop,
+  const char *zDb,                /* Database name */
+  const char *zTab,               /* Table name */
+  int bRowid,
+  int nCol,                       /* Number of columns in table */
+  const char **azCol,             /* Names of table columns */
+  u8 *abPK,                       /* PRIMARY KEY  array */
+  sqlite3_stmt **ppStmt           /* OUT: Prepared SELECT statement */
+){
+  int rc = SQLITE_OK;
+  char *zSql = 0;
+  const char *zSep = "";
+  int nSql = -1;
+  int i;
+
+  SessionBuffer cols = {0, 0, 0};
+  SessionBuffer nooptest = {0, 0, 0};
+  SessionBuffer pkfield = {0, 0, 0};
+  SessionBuffer pkvar = {0, 0, 0};
+
+  sessionAppendStr(&nooptest, ", 1", &rc);
+
+  if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){
+    sessionAppendStr(&nooptest, " AND (?6 OR ?3 IS stat)", &rc);
+    sessionAppendStr(&pkfield, "tbl, idx", &rc);
+    sessionAppendStr(&pkvar,
+        "?1, (CASE WHEN ?2=X'' THEN NULL ELSE ?2 END)", &rc
+    );
+    sessionAppendStr(&cols, "tbl, ?2, stat", &rc);
+  }else{
+  #if 0
+    if( bRowid ){
+      sessionAppendStr(&cols, SESSIONS_ROWID, &rc);
+    }
+    #endif
+    for(i=0; i<nCol; i++){
+      if( cols.nBuf ) sessionAppendStr(&cols, ", ", &rc);
+      sessionAppendIdent(&cols, azCol[i], &rc);
+      if( abPK[i] ){
+        sessionAppendStr(&pkfield, zSep, &rc);
+        sessionAppendStr(&pkvar, zSep, &rc);
+        zSep = ", ";
+        sessionAppendIdent(&pkfield, azCol[i], &rc);
+        sessionAppendPrintf(&pkvar, &rc, "?%d", i+1);
+      }else{
+        sessionAppendPrintf(&nooptest, &rc,
+            " AND (?%d OR ?%d IS %w.%w)", i+1+nCol, i+1, zTab, azCol[i]
+        );
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    zSql = sqlite3_mprintf(
+        "SELECT %s%s FROM %Q.%Q WHERE (%s) IS (%s)",
+        (char*)cols.aBuf, (bIgnoreNoop ? (char*)nooptest.aBuf : ""),
+        zDb, zTab, (char*)pkfield.aBuf, (char*)pkvar.aBuf
+    );
+    if( zSql==0 ) rc = SQLITE_NOMEM;
+  }
+
+#if 0
+  if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){
+    zSql = sqlite3_mprintf(
+        "SELECT tbl, ?2, stat FROM %Q.sqlite_stat1 WHERE tbl IS ?1 AND "
+        "idx IS (CASE WHEN ?2=X'' THEN NULL ELSE ?2 END)", zDb
+    );
+    if( zSql==0 ) rc = SQLITE_NOMEM;
+  }else{
+    const char *zSep = "";
+    SessionBuffer buf = {0, 0, 0};
+
+    sessionAppendStr(&buf, "SELECT * FROM ", &rc);
+    sessionAppendIdent(&buf, zDb, &rc);
+    sessionAppendStr(&buf, ".", &rc);
+    sessionAppendIdent(&buf, zTab, &rc);
+    sessionAppendStr(&buf, " WHERE ", &rc);
+    for(i=0; i<nCol; i++){
+      if( abPK[i] ){
+        sessionAppendStr(&buf, zSep, &rc);
+        sessionAppendIdent(&buf, azCol[i], &rc);
+        sessionAppendStr(&buf, " IS ?", &rc);
+        sessionAppendInteger(&buf, i+1, &rc);
+        zSep = " AND ";
+      }
+    }
+    zSql = (char*)buf.aBuf;
+    nSql = buf.nBuf;
+  }
+#endif
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_prepare_v2(db, zSql, nSql, ppStmt, 0);
+  }
+  sqlite3_free(zSql);
+  sqlite3_free(nooptest.aBuf);
+  sqlite3_free(pkfield.aBuf);
+  sqlite3_free(pkvar.aBuf);
+  sqlite3_free(cols.aBuf);
+  return rc;
+}
+
+/*
+** Bind the PRIMARY KEY values from the change passed in argument pChange
+** to the SELECT statement passed as the first argument. The SELECT statement
+** is as prepared by function sessionSelectStmt().
+**
+** Return SQLITE_OK if all PK values are successfully bound, or an SQLite
+** error code (e.g. SQLITE_NOMEM) otherwise.
+*/
+static int sessionSelectBind(
+  sqlite3_stmt *pSelect,          /* SELECT from sessionSelectStmt() */
+  int nCol,                       /* Number of columns in table */
+  u8 *abPK,                       /* PRIMARY KEY array */
+  SessionChange *pChange          /* Change structure */
+){
+  int i;
+  int rc = SQLITE_OK;
+  u8 *a = pChange->aRecord;
+
+  for(i=0; i<nCol && rc==SQLITE_OK; i++){
+    int eType = *a++;
+
+    switch( eType ){
+      case 0:
+      case SQLITE_NULL:
+        assert( abPK[i]==0 );
+        break;
+
+      case SQLITE_INTEGER: {
+        if( abPK[i] ){
+          i64 iVal = sessionGetI64(a);
+          rc = sqlite3_bind_int64(pSelect, i+1, iVal);
+        }
+        a += 8;
+        break;
+      }
+
+      case SQLITE_FLOAT: {
+        if( abPK[i] ){
+          double rVal;
+          i64 iVal = sessionGetI64(a);
+          memcpy(&rVal, &iVal, 8);
+          rc = sqlite3_bind_double(pSelect, i+1, rVal);
+        }
+        a += 8;
+        break;
+      }
+
+      case SQLITE_TEXT: {
+        int n;
+        a += sessionVarintGet(a, &n);
+        if( abPK[i] ){
+          rc = sqlite3_bind_text(pSelect, i+1, (char *)a, n, SQLITE_TRANSIENT);
+        }
+        a += n;
+        break;
+      }
+
+      default: {
+        int n;
+        assert( eType==SQLITE_BLOB );
+        a += sessionVarintGet(a, &n);
+        if( abPK[i] ){
+          rc = sqlite3_bind_blob(pSelect, i+1, a, n, SQLITE_TRANSIENT);
+        }
+        a += n;
+        break;
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is a no-op if *pRc is set to other than SQLITE_OK when it
+** is called. Otherwise, append a serialized table header (part of the binary
+** changeset format) to buffer *pBuf. If an error occurs, set *pRc to an
+** SQLite error code before returning.
+*/
+static void sessionAppendTableHdr(
+  SessionBuffer *pBuf,            /* Append header to this buffer */
+  int bPatchset,                  /* Use the patchset format if true */
+  SessionTable *pTab,             /* Table object to append header for */
+  int *pRc                        /* IN/OUT: Error code */
+){
+  /* Write a table header */
+  sessionAppendByte(pBuf, (bPatchset ? 'P' : 'T'), pRc);
+  sessionAppendVarint(pBuf, pTab->nCol, pRc);
+  sessionAppendBlob(pBuf, pTab->abPK, pTab->nCol, pRc);
+  sessionAppendBlob(pBuf, (u8 *)pTab->zName, (int)strlen(pTab->zName)+1, pRc);
+}
+
+/*
+** Generate either a changeset (if argument bPatchset is zero) or a patchset
+** (if it is non-zero) based on the current contents of the session object
+** passed as the first argument.
+**
+** If no error occurs, SQLITE_OK is returned and the new changeset/patchset
+** stored in output variables *pnChangeset and *ppChangeset. Or, if an error
+** occurs, an SQLite error code is returned and both output variables set
+** to 0.
+*/
+static int sessionGenerateChangeset(
+  sqlite3_session *pSession,      /* Session object */
+  int bPatchset,                  /* True for patchset, false for changeset */
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut,                     /* First argument for xOutput */
+  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
+  void **ppChangeset              /* OUT: Buffer containing changeset */
+){
+  sqlite3 *db = pSession->db;     /* Source database handle */
+  SessionTable *pTab;             /* Used to iterate through attached tables */
+  SessionBuffer buf = {0,0,0};    /* Buffer in which to accumlate changeset */
+  int rc;                         /* Return code */
+
+  assert( xOutput==0 || (pnChangeset==0 && ppChangeset==0) );
+  assert( xOutput!=0 || (pnChangeset!=0 && ppChangeset!=0) );
+
+  /* Zero the output variables in case an error occurs. If this session
+  ** object is already in the error state (sqlite3_session.rc != SQLITE_OK),
+  ** this call will be a no-op.  */
+  if( xOutput==0 ){
+    assert( pnChangeset!=0  && ppChangeset!=0 );
+    *pnChangeset = 0;
+    *ppChangeset = 0;
+  }
+
+  if( pSession->rc ) return pSession->rc;
+  rc = sqlite3_exec(pSession->db, "SAVEPOINT changeset", 0, 0, 0);
+  if( rc!=SQLITE_OK ) return rc;
+
+  sqlite3_mutex_enter(sqlite3_db_mutex(db));
+
+  for(pTab=pSession->pTable; rc==SQLITE_OK && pTab; pTab=pTab->pNext){
+    if( pTab->nEntry ){
+      const char *zName = pTab->zName;
+      int i;                      /* Used to iterate through hash buckets */
+      sqlite3_stmt *pSel = 0;     /* SELECT statement to query table pTab */
+      int nRewind = buf.nBuf;     /* Initial size of write buffer */
+      int nNoop;                  /* Size of buffer after writing tbl header */
+      int nOldCol = pTab->nCol;
+
+      /* Check the table schema is still Ok. */
+      rc = sessionReinitTable(pSession, pTab);
+      if( rc==SQLITE_OK && pTab->nCol!=nOldCol ){
+        rc = sessionUpdateChanges(pSession, pTab);
+      }
+
+      /* Write a table header */
+      sessionAppendTableHdr(&buf, bPatchset, pTab, &rc);
+
+      /* Build and compile a statement to execute: */
+      if( rc==SQLITE_OK ){
+        rc = sessionSelectStmt(db, 0, pSession->zDb,
+            zName, pTab->bRowid, pTab->nCol, pTab->azCol, pTab->abPK, &pSel
+        );
+      }
+
+      nNoop = buf.nBuf;
+      for(i=0; i<pTab->nChange && rc==SQLITE_OK; i++){
+        SessionChange *p;         /* Used to iterate through changes */
+
+        for(p=pTab->apChange[i]; rc==SQLITE_OK && p; p=p->pNext){
+          rc = sessionSelectBind(pSel, pTab->nCol, pTab->abPK, p);
+          if( rc!=SQLITE_OK ) continue;
+          if( sqlite3_step(pSel)==SQLITE_ROW ){
+            if( p->op==SQLITE_INSERT ){
+              int iCol;
+              sessionAppendByte(&buf, SQLITE_INSERT, &rc);
+              sessionAppendByte(&buf, p->bIndirect, &rc);
+              for(iCol=0; iCol<pTab->nCol; iCol++){
+                sessionAppendCol(&buf, pSel, iCol, &rc);
+              }
+            }else{
+              assert( pTab->abPK!=0 );
+              rc = sessionAppendUpdate(&buf, bPatchset, pSel, p, pTab->abPK);
+            }
+          }else if( p->op!=SQLITE_INSERT ){
+            rc = sessionAppendDelete(&buf, bPatchset, p, pTab->nCol,pTab->abPK);
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3_reset(pSel);
+          }
+
+          /* If the buffer is now larger than sessions_strm_chunk_size, pass
+          ** its contents to the xOutput() callback. */
+          if( xOutput
+           && rc==SQLITE_OK
+           && buf.nBuf>nNoop
+           && buf.nBuf>sessions_strm_chunk_size
+          ){
+            rc = xOutput(pOut, (void*)buf.aBuf, buf.nBuf);
+            nNoop = -1;
+            buf.nBuf = 0;
+          }
+
+        }
+      }
+
+      sqlite3_finalize(pSel);
+      if( buf.nBuf==nNoop ){
+        buf.nBuf = nRewind;
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( xOutput==0 ){
+      *pnChangeset = buf.nBuf;
+      *ppChangeset = buf.aBuf;
+      buf.aBuf = 0;
+    }else if( buf.nBuf>0 ){
+      rc = xOutput(pOut, (void*)buf.aBuf, buf.nBuf);
+    }
+  }
+
+  sqlite3_free(buf.aBuf);
+  sqlite3_exec(db, "RELEASE changeset", 0, 0, 0);
+  sqlite3_mutex_leave(sqlite3_db_mutex(db));
+  return rc;
+}
+
+/*
+** Obtain a changeset object containing all changes recorded by the
+** session object passed as the first argument.
+**
+** It is the responsibility of the caller to eventually free the buffer
+** using sqlite3_free().
+*/
+SQLITE_API int sqlite3session_changeset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
+  void **ppChangeset              /* OUT: Buffer containing changeset */
+){
+  int rc;
+
+  if( pnChangeset==0 || ppChangeset==0 ) return SQLITE_MISUSE;
+  rc = sessionGenerateChangeset(pSession, 0, 0, 0, pnChangeset, ppChangeset);
+  assert( rc || pnChangeset==0
+       || pSession->bEnableSize==0 || *pnChangeset<=pSession->nMaxChangesetSize
+  );
+  return rc;
+}
+
+/*
+** Streaming version of sqlite3session_changeset().
+*/
+SQLITE_API int sqlite3session_changeset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  if( xOutput==0 ) return SQLITE_MISUSE;
+  return sessionGenerateChangeset(pSession, 0, xOutput, pOut, 0, 0);
+}
+
+/*
+** Streaming version of sqlite3session_patchset().
+*/
+SQLITE_API int sqlite3session_patchset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  if( xOutput==0 ) return SQLITE_MISUSE;
+  return sessionGenerateChangeset(pSession, 1, xOutput, pOut, 0, 0);
+}
+
+/*
+** Obtain a patchset object containing all changes recorded by the
+** session object passed as the first argument.
+**
+** It is the responsibility of the caller to eventually free the buffer
+** using sqlite3_free().
+*/
+SQLITE_API int sqlite3session_patchset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnPatchset,                /* OUT: Size of buffer at *ppChangeset */
+  void **ppPatchset               /* OUT: Buffer containing changeset */
+){
+  if( pnPatchset==0 || ppPatchset==0 ) return SQLITE_MISUSE;
+  return sessionGenerateChangeset(pSession, 1, 0, 0, pnPatchset, ppPatchset);
+}
+
+/*
+** Enable or disable the session object passed as the first argument.
+*/
+SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable){
+  int ret;
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+  if( bEnable>=0 ){
+    pSession->bEnable = bEnable;
+  }
+  ret = pSession->bEnable;
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+  return ret;
+}
+
+/*
+** Enable or disable the session object passed as the first argument.
+*/
+SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect){
+  int ret;
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+  if( bIndirect>=0 ){
+    pSession->bIndirect = bIndirect;
+  }
+  ret = pSession->bIndirect;
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+  return ret;
+}
+
+/*
+** Return true if there have been no changes to monitored tables recorded
+** by the session object passed as the only argument.
+*/
+SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession){
+  int ret = 0;
+  SessionTable *pTab;
+
+  sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db));
+  for(pTab=pSession->pTable; pTab && ret==0; pTab=pTab->pNext){
+    ret = (pTab->nEntry>0);
+  }
+  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));
+
+  return (ret==0);
+}
+
+/*
+** Return the amount of heap memory in use.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession){
+  return pSession->nMalloc;
+}
+
+/*
+** Configure the session object passed as the first argument.
+*/
+SQLITE_API int sqlite3session_object_config(sqlite3_session *pSession, int op, void *pArg){
+  int rc = SQLITE_OK;
+  switch( op ){
+    case SQLITE_SESSION_OBJCONFIG_SIZE: {
+      int iArg = *(int*)pArg;
+      if( iArg>=0 ){
+        if( pSession->pTable ){
+          rc = SQLITE_MISUSE;
+        }else{
+          pSession->bEnableSize = (iArg!=0);
+        }
+      }
+      *(int*)pArg = pSession->bEnableSize;
+      break;
+    }
+
+    case SQLITE_SESSION_OBJCONFIG_ROWID: {
+      int iArg = *(int*)pArg;
+      if( iArg>=0 ){
+        if( pSession->pTable ){
+          rc = SQLITE_MISUSE;
+        }else{
+          pSession->bImplicitPK = (iArg!=0);
+        }
+      }
+      *(int*)pArg = pSession->bImplicitPK;
+      break;
+    }
+
+    default:
+      rc = SQLITE_MISUSE;
+  }
+
+  return rc;
+}
+
+/*
+** Return the maximum size of sqlite3session_changeset() output.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession){
+  return pSession->nMaxChangesetSize;
+}
+
+/*
+** Do the work for either sqlite3changeset_start() or start_strm().
+*/
+static int sessionChangesetStart(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int nChangeset,                 /* Size of buffer pChangeset in bytes */
+  void *pChangeset,               /* Pointer to buffer containing changeset */
+  int bInvert,                    /* True to invert changeset */
+  int bSkipEmpty                  /* True to skip empty UPDATE changes */
+){
+  sqlite3_changeset_iter *pRet;   /* Iterator to return */
+  int nByte;                      /* Number of bytes to allocate for iterator */
+
+  assert( xInput==0 || (pChangeset==0 && nChangeset==0) );
+
+  /* Zero the output variable in case an error occurs. */
+  *pp = 0;
+
+  /* Allocate and initialize the iterator structure. */
+  nByte = sizeof(sqlite3_changeset_iter);
+  pRet = (sqlite3_changeset_iter *)sqlite3_malloc(nByte);
+  if( !pRet ) return SQLITE_NOMEM;
+  memset(pRet, 0, sizeof(sqlite3_changeset_iter));
+  pRet->in.aData = (u8 *)pChangeset;
+  pRet->in.nData = nChangeset;
+  pRet->in.xInput = xInput;
+  pRet->in.pIn = pIn;
+  pRet->in.bEof = (xInput ? 0 : 1);
+  pRet->bInvert = bInvert;
+  pRet->bSkipEmpty = bSkipEmpty;
+
+  /* Populate the output variable and return success. */
+  *pp = pRet;
+  return SQLITE_OK;
+}
+
+/*
+** Create an iterator used to iterate through the contents of a changeset.
+*/
+SQLITE_API int sqlite3changeset_start(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int nChangeset,                 /* Size of buffer pChangeset in bytes */
+  void *pChangeset                /* Pointer to buffer containing changeset */
+){
+  return sessionChangesetStart(pp, 0, 0, nChangeset, pChangeset, 0, 0);
+}
+SQLITE_API int sqlite3changeset_start_v2(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int nChangeset,                 /* Size of buffer pChangeset in bytes */
+  void *pChangeset,               /* Pointer to buffer containing changeset */
+  int flags
+){
+  int bInvert = !!(flags & SQLITE_CHANGESETSTART_INVERT);
+  return sessionChangesetStart(pp, 0, 0, nChangeset, pChangeset, bInvert, 0);
+}
+
+/*
+** Streaming version of sqlite3changeset_start().
+*/
+SQLITE_API int sqlite3changeset_start_strm(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn
+){
+  return sessionChangesetStart(pp, xInput, pIn, 0, 0, 0, 0);
+}
+SQLITE_API int sqlite3changeset_start_v2_strm(
+  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int flags
+){
+  int bInvert = !!(flags & SQLITE_CHANGESETSTART_INVERT);
+  return sessionChangesetStart(pp, xInput, pIn, 0, 0, bInvert, 0);
+}
+
+/*
+** If the SessionInput object passed as the only argument is a streaming
+** object and the buffer is full, discard some data to free up space.
+*/
+static void sessionDiscardData(SessionInput *pIn){
+  if( pIn->xInput && pIn->iNext>=sessions_strm_chunk_size ){
+    int nMove = pIn->buf.nBuf - pIn->iNext;
+    assert( nMove>=0 );
+    if( nMove>0 ){
+      memmove(pIn->buf.aBuf, &pIn->buf.aBuf[pIn->iNext], nMove);
+    }
+    pIn->buf.nBuf -= pIn->iNext;
+    pIn->iNext = 0;
+    pIn->nData = pIn->buf.nBuf;
+  }
+}
+
+/*
+** Ensure that there are at least nByte bytes available in the buffer. Or,
+** if there are not nByte bytes remaining in the input, that all available
+** data is in the buffer.
+**
+** Return an SQLite error code if an error occurs, or SQLITE_OK otherwise.
+*/
+static int sessionInputBuffer(SessionInput *pIn, int nByte){
+  int rc = SQLITE_OK;
+  if( pIn->xInput ){
+    while( !pIn->bEof && (pIn->iNext+nByte)>=pIn->nData && rc==SQLITE_OK ){
+      int nNew = sessions_strm_chunk_size;
+
+      if( pIn->bNoDiscard==0 ) sessionDiscardData(pIn);
+      if( SQLITE_OK==sessionBufferGrow(&pIn->buf, nNew, &rc) ){
+        rc = pIn->xInput(pIn->pIn, &pIn->buf.aBuf[pIn->buf.nBuf], &nNew);
+        if( nNew==0 ){
+          pIn->bEof = 1;
+        }else{
+          pIn->buf.nBuf += nNew;
+        }
+      }
+
+      pIn->aData = pIn->buf.aBuf;
+      pIn->nData = pIn->buf.nBuf;
+    }
+  }
+  return rc;
+}
+
+/*
+** When this function is called, *ppRec points to the start of a record
+** that contains nCol values. This function advances the pointer *ppRec
+** until it points to the byte immediately following that record.
+*/
+static void sessionSkipRecord(
+  u8 **ppRec,                     /* IN/OUT: Record pointer */
+  int nCol                        /* Number of values in record */
+){
+  u8 *aRec = *ppRec;
+  int i;
+  for(i=0; i<nCol; i++){
+    int eType = *aRec++;
+    if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
+      int nByte;
+      aRec += sessionVarintGet((u8*)aRec, &nByte);
+      aRec += nByte;
+    }else if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+      aRec += 8;
+    }
+  }
+
+  *ppRec = aRec;
+}
+
+/*
+** This function sets the value of the sqlite3_value object passed as the
+** first argument to a copy of the string or blob held in the aData[]
+** buffer. SQLITE_OK is returned if successful, or SQLITE_NOMEM if an OOM
+** error occurs.
+*/
+static int sessionValueSetStr(
+  sqlite3_value *pVal,            /* Set the value of this object */
+  u8 *aData,                      /* Buffer containing string or blob data */
+  int nData,                      /* Size of buffer aData[] in bytes */
+  u8 enc                          /* String encoding (0 for blobs) */
+){
+  /* In theory this code could just pass SQLITE_TRANSIENT as the final
+  ** argument to sqlite3ValueSetStr() and have the copy created
+  ** automatically. But doing so makes it difficult to detect any OOM
+  ** error. Hence the code to create the copy externally. */
+  u8 *aCopy = sqlite3_malloc64((sqlite3_int64)nData+1);
+  if( aCopy==0 ) return SQLITE_NOMEM;
+  memcpy(aCopy, aData, nData);
+  sqlite3ValueSetStr(pVal, nData, (char*)aCopy, enc, sqlite3_free);
+  return SQLITE_OK;
+}
+
+/*
+** Deserialize a single record from a buffer in memory. See "RECORD FORMAT"
+** for details.
+**
+** When this function is called, *paChange points to the start of the record
+** to deserialize. Assuming no error occurs, *paChange is set to point to
+** one byte after the end of the same record before this function returns.
+** If the argument abPK is NULL, then the record contains nCol values. Or,
+** if abPK is other than NULL, then the record contains only the PK fields
+** (in other words, it is a patchset DELETE record).
+**
+** If successful, each element of the apOut[] array (allocated by the caller)
+** is set to point to an sqlite3_value object containing the value read
+** from the corresponding position in the record. If that value is not
+** included in the record (i.e. because the record is part of an UPDATE change
+** and the field was not modified), the corresponding element of apOut[] is
+** set to NULL.
+**
+** It is the responsibility of the caller to free all sqlite_value structures
+** using sqlite3_free().
+**
+** If an error occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
+** The apOut[] array may have been partially populated in this case.
+*/
+static int sessionReadRecord(
+  SessionInput *pIn,              /* Input data */
+  int nCol,                       /* Number of values in record */
+  u8 *abPK,                       /* Array of primary key flags, or NULL */
+  sqlite3_value **apOut,          /* Write values to this array */
+  int *pbEmpty
+){
+  int i;                          /* Used to iterate through columns */
+  int rc = SQLITE_OK;
+
+  assert( pbEmpty==0 || *pbEmpty==0 );
+  if( pbEmpty ) *pbEmpty = 1;
+  for(i=0; i<nCol && rc==SQLITE_OK; i++){
+    int eType = 0;                /* Type of value (SQLITE_NULL, TEXT etc.) */
+    if( abPK && abPK[i]==0 ) continue;
+    rc = sessionInputBuffer(pIn, 9);
+    if( rc==SQLITE_OK ){
+      if( pIn->iNext>=pIn->nData ){
+        rc = SQLITE_CORRUPT_BKPT;
+      }else{
+        eType = pIn->aData[pIn->iNext++];
+        assert( apOut[i]==0 );
+        if( eType ){
+          if( pbEmpty ) *pbEmpty = 0;
+          apOut[i] = sqlite3ValueNew(0);
+          if( !apOut[i] ) rc = SQLITE_NOMEM;
+        }
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      u8 *aVal = &pIn->aData[pIn->iNext];
+      if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
+        int nByte;
+        pIn->iNext += sessionVarintGet(aVal, &nByte);
+        rc = sessionInputBuffer(pIn, nByte);
+        if( rc==SQLITE_OK ){
+          if( nByte<0 || nByte>pIn->nData-pIn->iNext ){
+            rc = SQLITE_CORRUPT_BKPT;
+          }else{
+            u8 enc = (eType==SQLITE_TEXT ? SQLITE_UTF8 : 0);
+            rc = sessionValueSetStr(apOut[i],&pIn->aData[pIn->iNext],nByte,enc);
+            pIn->iNext += nByte;
+          }
+        }
+      }
+      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+        if( (pIn->nData-pIn->iNext)<8 ){
+          rc = SQLITE_CORRUPT_BKPT;
+        }else{
+          sqlite3_int64 v = sessionGetI64(aVal);
+          if( eType==SQLITE_INTEGER ){
+            sqlite3VdbeMemSetInt64(apOut[i], v);
+          }else{
+            double d;
+            memcpy(&d, &v, 8);
+            sqlite3VdbeMemSetDouble(apOut[i], d);
+          }
+          pIn->iNext += 8;
+        }
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The input pointer currently points to the second byte of a table-header.
+** Specifically, to the following:
+**
+**   + number of columns in table (varint)
+**   + array of PK flags (1 byte per column),
+**   + table name (nul terminated).
+**
+** This function ensures that all of the above is present in the input
+** buffer (i.e. that it can be accessed without any calls to xInput()).
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
+** The input pointer is not moved.
+*/
+static int sessionChangesetBufferTblhdr(SessionInput *pIn, int *pnByte){
+  int rc = SQLITE_OK;
+  int nCol = 0;
+  int nRead = 0;
+
+  rc = sessionInputBuffer(pIn, 9);
+  if( rc==SQLITE_OK ){
+    nRead += sessionVarintGet(&pIn->aData[pIn->iNext + nRead], &nCol);
+    /* The hard upper limit for the number of columns in an SQLite
+    ** database table is, according to sqliteLimit.h, 32676. So
+    ** consider any table-header that purports to have more than 65536
+    ** columns to be corrupt. This is convenient because otherwise,
+    ** if the (nCol>65536) condition below were omitted, a sufficiently
+    ** large value for nCol may cause nRead to wrap around and become
+    ** negative. Leading to a crash. */
+    if( nCol<0 || nCol>65536 ){
+      rc = SQLITE_CORRUPT_BKPT;
+    }else{
+      rc = sessionInputBuffer(pIn, nRead+nCol+100);
+      nRead += nCol;
+    }
+  }
+
+  while( rc==SQLITE_OK ){
+    while( (pIn->iNext + nRead)<pIn->nData && pIn->aData[pIn->iNext + nRead] ){
+      nRead++;
+    }
+    if( (pIn->iNext + nRead)<pIn->nData ) break;
+    rc = sessionInputBuffer(pIn, nRead + 100);
+  }
+  *pnByte = nRead+1;
+  return rc;
+}
+
+/*
+** The input pointer currently points to the first byte of the first field
+** of a record consisting of nCol columns. This function ensures the entire
+** record is buffered. It does not move the input pointer.
+**
+** If successful, SQLITE_OK is returned and *pnByte is set to the size of
+** the record in bytes. Otherwise, an SQLite error code is returned. The
+** final value of *pnByte is undefined in this case.
+*/
+static int sessionChangesetBufferRecord(
+  SessionInput *pIn,              /* Input data */
+  int nCol,                       /* Number of columns in record */
+  int *pnByte                     /* OUT: Size of record in bytes */
+){
+  int rc = SQLITE_OK;
+  int nByte = 0;
+  int i;
+  for(i=0; rc==SQLITE_OK && i<nCol; i++){
+    int eType;
+    rc = sessionInputBuffer(pIn, nByte + 10);
+    if( rc==SQLITE_OK ){
+      eType = pIn->aData[pIn->iNext + nByte++];
+      if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
+        int n;
+        nByte += sessionVarintGet(&pIn->aData[pIn->iNext+nByte], &n);
+        nByte += n;
+        rc = sessionInputBuffer(pIn, nByte);
+      }else if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
+        nByte += 8;
+      }
+    }
+  }
+  *pnByte = nByte;
+  return rc;
+}
+
+/*
+** The input pointer currently points to the second byte of a table-header.
+** Specifically, to the following:
+**
+**   + number of columns in table (varint)
+**   + array of PK flags (1 byte per column),
+**   + table name (nul terminated).
+**
+** This function decodes the table-header and populates the p->nCol,
+** p->zTab and p->abPK[] variables accordingly. The p->apValue[] array is
+** also allocated or resized according to the new value of p->nCol. The
+** input pointer is left pointing to the byte following the table header.
+**
+** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code
+** is returned and the final values of the various fields enumerated above
+** are undefined.
+*/
+static int sessionChangesetReadTblhdr(sqlite3_changeset_iter *p){
+  int rc;
+  int nCopy;
+  assert( p->rc==SQLITE_OK );
+
+  rc = sessionChangesetBufferTblhdr(&p->in, &nCopy);
+  if( rc==SQLITE_OK ){
+    int nByte;
+    int nVarint;
+    nVarint = sessionVarintGet(&p->in.aData[p->in.iNext], &p->nCol);
+    if( p->nCol>0 ){
+      nCopy -= nVarint;
+      p->in.iNext += nVarint;
+      nByte = p->nCol * sizeof(sqlite3_value*) * 2 + nCopy;
+      p->tblhdr.nBuf = 0;
+      sessionBufferGrow(&p->tblhdr, nByte, &rc);
+    }else{
+      rc = SQLITE_CORRUPT_BKPT;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    size_t iPK = sizeof(sqlite3_value*)*p->nCol*2;
+    memset(p->tblhdr.aBuf, 0, iPK);
+    memcpy(&p->tblhdr.aBuf[iPK], &p->in.aData[p->in.iNext], nCopy);
+    p->in.iNext += nCopy;
+  }
+
+  p->apValue = (sqlite3_value**)p->tblhdr.aBuf;
+  if( p->apValue==0 ){
+    p->abPK = 0;
+    p->zTab = 0;
+  }else{
+    p->abPK = (u8*)&p->apValue[p->nCol*2];
+    p->zTab = p->abPK ? (char*)&p->abPK[p->nCol] : 0;
+  }
+  return (p->rc = rc);
+}
+
+/*
+** Advance the changeset iterator to the next change. The differences between
+** this function and sessionChangesetNext() are that
+**
+**   * If pbEmpty is not NULL and the change is a no-op UPDATE (an UPDATE
+**     that modifies no columns), this function sets (*pbEmpty) to 1.
+**
+**   * If the iterator is configured to skip no-op UPDATEs,
+**     sessionChangesetNext() does that. This function does not.
+*/
+static int sessionChangesetNextOne(
+  sqlite3_changeset_iter *p,      /* Changeset iterator */
+  u8 **paRec,                     /* If non-NULL, store record pointer here */
+  int *pnRec,                     /* If non-NULL, store size of record here */
+  int *pbNew,                     /* If non-NULL, true if new table */
+  int *pbEmpty
+){
+  int i;
+  u8 op;
+
+  assert( (paRec==0 && pnRec==0) || (paRec && pnRec) );
+  assert( pbEmpty==0 || *pbEmpty==0 );
+
+  /* If the iterator is in the error-state, return immediately. */
+  if( p->rc!=SQLITE_OK ) return p->rc;
+
+  /* Free the current contents of p->apValue[], if any. */
+  if( p->apValue ){
+    for(i=0; i<p->nCol*2; i++){
+      sqlite3ValueFree(p->apValue[i]);
+    }
+    memset(p->apValue, 0, sizeof(sqlite3_value*)*p->nCol*2);
+  }
+
+  /* Make sure the buffer contains at least 10 bytes of input data, or all
+  ** remaining data if there are less than 10 bytes available. This is
+  ** sufficient either for the 'T' or 'P' byte and the varint that follows
+  ** it, or for the two single byte values otherwise. */
+  p->rc = sessionInputBuffer(&p->in, 2);
+  if( p->rc!=SQLITE_OK ) return p->rc;
+
+  sessionDiscardData(&p->in);
+  p->in.iCurrent = p->in.iNext;
+
+  /* If the iterator is already at the end of the changeset, return DONE. */
+  if( p->in.iNext>=p->in.nData ){
+    return SQLITE_DONE;
+  }
+
+  op = p->in.aData[p->in.iNext++];
+  while( op=='T' || op=='P' ){
+    if( pbNew ) *pbNew = 1;
+    p->bPatchset = (op=='P');
+    if( sessionChangesetReadTblhdr(p) ) return p->rc;
+    if( (p->rc = sessionInputBuffer(&p->in, 2)) ) return p->rc;
+    p->in.iCurrent = p->in.iNext;
+    if( p->in.iNext>=p->in.nData ) return SQLITE_DONE;
+    op = p->in.aData[p->in.iNext++];
+  }
+
+  if( p->zTab==0 || (p->bPatchset && p->bInvert) ){
+    /* The first record in the changeset is not a table header. Must be a
+    ** corrupt changeset. */
+    assert( p->in.iNext==1 || p->zTab );
+    return (p->rc = SQLITE_CORRUPT_BKPT);
+  }
+
+  p->op = op;
+  p->bIndirect = p->in.aData[p->in.iNext++];
+  if( p->op!=SQLITE_UPDATE && p->op!=SQLITE_DELETE && p->op!=SQLITE_INSERT ){
+    return (p->rc = SQLITE_CORRUPT_BKPT);
+  }
+
+  if( paRec ){
+    int nVal;                     /* Number of values to buffer */
+    if( p->bPatchset==0 && op==SQLITE_UPDATE ){
+      nVal = p->nCol * 2;
+    }else if( p->bPatchset && op==SQLITE_DELETE ){
+      nVal = 0;
+      for(i=0; i<p->nCol; i++) if( p->abPK[i] ) nVal++;
+    }else{
+      nVal = p->nCol;
+    }
+    p->rc = sessionChangesetBufferRecord(&p->in, nVal, pnRec);
+    if( p->rc!=SQLITE_OK ) return p->rc;
+    *paRec = &p->in.aData[p->in.iNext];
+    p->in.iNext += *pnRec;
+  }else{
+    sqlite3_value **apOld = (p->bInvert ? &p->apValue[p->nCol] : p->apValue);
+    sqlite3_value **apNew = (p->bInvert ? p->apValue : &p->apValue[p->nCol]);
+
+    /* If this is an UPDATE or DELETE, read the old.* record. */
+    if( p->op!=SQLITE_INSERT && (p->bPatchset==0 || p->op==SQLITE_DELETE) ){
+      u8 *abPK = p->bPatchset ? p->abPK : 0;
+      p->rc = sessionReadRecord(&p->in, p->nCol, abPK, apOld, 0);
+      if( p->rc!=SQLITE_OK ) return p->rc;
+    }
+
+    /* If this is an INSERT or UPDATE, read the new.* record. */
+    if( p->op!=SQLITE_DELETE ){
+      p->rc = sessionReadRecord(&p->in, p->nCol, 0, apNew, pbEmpty);
+      if( p->rc!=SQLITE_OK ) return p->rc;
+    }
+
+    if( (p->bPatchset || p->bInvert) && p->op==SQLITE_UPDATE ){
+      /* If this is an UPDATE that is part of a patchset, then all PK and
+      ** modified fields are present in the new.* record. The old.* record
+      ** is currently completely empty. This block shifts the PK fields from
+      ** new.* to old.*, to accommodate the code that reads these arrays.  */
+      for(i=0; i<p->nCol; i++){
+        assert( p->bPatchset==0 || p->apValue[i]==0 );
+        if( p->abPK[i] ){
+          assert( p->apValue[i]==0 );
+          p->apValue[i] = p->apValue[i+p->nCol];
+          if( p->apValue[i]==0 ) return (p->rc = SQLITE_CORRUPT_BKPT);
+          p->apValue[i+p->nCol] = 0;
+        }
+      }
+    }else if( p->bInvert ){
+      if( p->op==SQLITE_INSERT ) p->op = SQLITE_DELETE;
+      else if( p->op==SQLITE_DELETE ) p->op = SQLITE_INSERT;
+    }
+
+    /* If this is an UPDATE that is part of a changeset, then check that
+    ** there are no fields in the old.* record that are not (a) PK fields,
+    ** or (b) also present in the new.* record.
+    **
+    ** Such records are technically corrupt, but the rebaser was at one
+    ** point generating them. Under most circumstances this is benign, but
+    ** can cause spurious SQLITE_RANGE errors when applying the changeset. */
+    if( p->bPatchset==0 && p->op==SQLITE_UPDATE){
+      for(i=0; i<p->nCol; i++){
+        if( p->abPK[i]==0 && p->apValue[i+p->nCol]==0 ){
+          sqlite3ValueFree(p->apValue[i]);
+          p->apValue[i] = 0;
+        }
+      }
+    }
+  }
+
+  return SQLITE_ROW;
+}
+
+/*
+** Advance the changeset iterator to the next change.
+**
+** If both paRec and pnRec are NULL, then this function works like the public
+** API sqlite3changeset_next(). If SQLITE_ROW is returned, then the
+** sqlite3changeset_new() and old() APIs may be used to query for values.
+**
+** Otherwise, if paRec and pnRec are not NULL, then a pointer to the change
+** record is written to *paRec before returning and the number of bytes in
+** the record to *pnRec.
+**
+** Either way, this function returns SQLITE_ROW if the iterator is
+** successfully advanced to the next change in the changeset, an SQLite
+** error code if an error occurs, or SQLITE_DONE if there are no further
+** changes in the changeset.
+*/
+static int sessionChangesetNext(
+  sqlite3_changeset_iter *p,      /* Changeset iterator */
+  u8 **paRec,                     /* If non-NULL, store record pointer here */
+  int *pnRec,                     /* If non-NULL, store size of record here */
+  int *pbNew                      /* If non-NULL, true if new table */
+){
+  int bEmpty;
+  int rc;
+  do {
+    bEmpty = 0;
+    rc = sessionChangesetNextOne(p, paRec, pnRec, pbNew, &bEmpty);
+  }while( rc==SQLITE_ROW && p->bSkipEmpty && bEmpty);
+  return rc;
+}
+
+/*
+** Advance an iterator created by sqlite3changeset_start() to the next
+** change in the changeset. This function may return SQLITE_ROW, SQLITE_DONE
+** or SQLITE_CORRUPT.
+**
+** This function may not be called on iterators passed to a conflict handler
+** callback by changeset_apply().
+*/
+SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *p){
+  return sessionChangesetNext(p, 0, 0, 0);
+}
+
+/*
+** The following function extracts information on the current change
+** from a changeset iterator. It may only be called after changeset_next()
+** has returned SQLITE_ROW.
+*/
+SQLITE_API int sqlite3changeset_op(
+  sqlite3_changeset_iter *pIter,  /* Iterator handle */
+  const char **pzTab,             /* OUT: Pointer to table name */
+  int *pnCol,                     /* OUT: Number of columns in table */
+  int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
+  int *pbIndirect                 /* OUT: True if change is indirect */
+){
+  *pOp = pIter->op;
+  *pnCol = pIter->nCol;
+  *pzTab = pIter->zTab;
+  if( pbIndirect ) *pbIndirect = pIter->bIndirect;
+  return SQLITE_OK;
+}
+
+/*
+** Return information regarding the PRIMARY KEY and number of columns in
+** the database table affected by the change that pIter currently points
+** to. This function may only be called after changeset_next() returns
+** SQLITE_ROW.
+*/
+SQLITE_API int sqlite3changeset_pk(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
+  int *pnCol                      /* OUT: Number of entries in output array */
+){
+  *pabPK = pIter->abPK;
+  if( pnCol ) *pnCol = pIter->nCol;
+  return SQLITE_OK;
+}
+
+/*
+** This function may only be called while the iterator is pointing to an
+** SQLITE_UPDATE or SQLITE_DELETE change (see sqlite3changeset_op()).
+** Otherwise, SQLITE_MISUSE is returned.
+**
+** It sets *ppValue to point to an sqlite3_value structure containing the
+** iVal'th value in the old.* record. Or, if that particular value is not
+** included in the record (because the change is an UPDATE and the field
+** was not modified and is not a PK column), set *ppValue to NULL.
+**
+** If value iVal is out-of-range, SQLITE_RANGE is returned and *ppValue is
+** not modified. Otherwise, SQLITE_OK.
+*/
+SQLITE_API int sqlite3changeset_old(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Index of old.* value to retrieve */
+  sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
+){
+  if( pIter->op!=SQLITE_UPDATE && pIter->op!=SQLITE_DELETE ){
+    return SQLITE_MISUSE;
+  }
+  if( iVal<0 || iVal>=pIter->nCol ){
+    return SQLITE_RANGE;
+  }
+  *ppValue = pIter->apValue[iVal];
+  return SQLITE_OK;
+}
+
+/*
+** This function may only be called while the iterator is pointing to an
+** SQLITE_UPDATE or SQLITE_INSERT change (see sqlite3changeset_op()).
+** Otherwise, SQLITE_MISUSE is returned.
+**
+** It sets *ppValue to point to an sqlite3_value structure containing the
+** iVal'th value in the new.* record. Or, if that particular value is not
+** included in the record (because the change is an UPDATE and the field
+** was not modified), set *ppValue to NULL.
+**
+** If value iVal is out-of-range, SQLITE_RANGE is returned and *ppValue is
+** not modified. Otherwise, SQLITE_OK.
+*/
+SQLITE_API int sqlite3changeset_new(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Index of new.* value to retrieve */
+  sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
+){
+  if( pIter->op!=SQLITE_UPDATE && pIter->op!=SQLITE_INSERT ){
+    return SQLITE_MISUSE;
+  }
+  if( iVal<0 || iVal>=pIter->nCol ){
+    return SQLITE_RANGE;
+  }
+  *ppValue = pIter->apValue[pIter->nCol+iVal];
+  return SQLITE_OK;
+}
+
+/*
+** The following two macros are used internally. They are similar to the
+** sqlite3changeset_new() and sqlite3changeset_old() functions, except that
+** they omit all error checking and return a pointer to the requested value.
+*/
+#define sessionChangesetNew(pIter, iVal) (pIter)->apValue[(pIter)->nCol+(iVal)]
+#define sessionChangesetOld(pIter, iVal) (pIter)->apValue[(iVal)]
+
+/*
+** This function may only be called with a changeset iterator that has been
+** passed to an SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT
+** conflict-handler function. Otherwise, SQLITE_MISUSE is returned.
+**
+** If successful, *ppValue is set to point to an sqlite3_value structure
+** containing the iVal'th value of the conflicting record.
+**
+** If value iVal is out-of-range or some other error occurs, an SQLite error
+** code is returned. Otherwise, SQLITE_OK.
+*/
+SQLITE_API int sqlite3changeset_conflict(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Index of conflict record value to fetch */
+  sqlite3_value **ppValue         /* OUT: Value from conflicting row */
+){
+  if( !pIter->pConflict ){
+    return SQLITE_MISUSE;
+  }
+  if( iVal<0 || iVal>=pIter->nCol ){
+    return SQLITE_RANGE;
+  }
+  *ppValue = sqlite3_column_value(pIter->pConflict, iVal);
+  return SQLITE_OK;
+}
+
+/*
+** This function may only be called with an iterator passed to an
+** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
+** it sets the output variable to the total number of known foreign key
+** violations in the destination database and returns SQLITE_OK.
+**
+** In all other cases this function returns SQLITE_MISUSE.
+*/
+SQLITE_API int sqlite3changeset_fk_conflicts(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int *pnOut                      /* OUT: Number of FK violations */
+){
+  if( pIter->pConflict || pIter->apValue ){
+    return SQLITE_MISUSE;
+  }
+  *pnOut = pIter->nCol;
+  return SQLITE_OK;
+}
+
+
+/*
+** Finalize an iterator allocated with sqlite3changeset_start().
+**
+** This function may not be called on iterators passed to a conflict handler
+** callback by changeset_apply().
+*/
+SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *p){
+  int rc = SQLITE_OK;
+  if( p ){
+    int i;                        /* Used to iterate through p->apValue[] */
+    rc = p->rc;
+    if( p->apValue ){
+      for(i=0; i<p->nCol*2; i++) sqlite3ValueFree(p->apValue[i]);
+    }
+    sqlite3_free(p->tblhdr.aBuf);
+    sqlite3_free(p->in.buf.aBuf);
+    sqlite3_free(p);
+  }
+  return rc;
+}
+
+static int sessionChangesetInvert(
+  SessionInput *pInput,           /* Input changeset */
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut,
+  int *pnInverted,                /* OUT: Number of bytes in output changeset */
+  void **ppInverted               /* OUT: Inverse of pChangeset */
+){
+  int rc = SQLITE_OK;             /* Return value */
+  SessionBuffer sOut;             /* Output buffer */
+  int nCol = 0;                   /* Number of cols in current table */
+  u8 *abPK = 0;                   /* PK array for current table */
+  sqlite3_value **apVal = 0;      /* Space for values for UPDATE inversion */
+  SessionBuffer sPK = {0, 0, 0};  /* PK array for current table */
+
+  /* Initialize the output buffer */
+  memset(&sOut, 0, sizeof(SessionBuffer));
+
+  /* Zero the output variables in case an error occurs. */
+  if( ppInverted ){
+    *ppInverted = 0;
+    *pnInverted = 0;
+  }
+
+  while( 1 ){
+    u8 eType;
+
+    /* Test for EOF. */
+    if( (rc = sessionInputBuffer(pInput, 2)) ) goto finished_invert;
+    if( pInput->iNext>=pInput->nData ) break;
+    eType = pInput->aData[pInput->iNext];
+
+    switch( eType ){
+      case 'T': {
+        /* A 'table' record consists of:
+        **
+        **   * A constant 'T' character,
+        **   * Number of columns in said table (a varint),
+        **   * An array of nCol bytes (sPK),
+        **   * A nul-terminated table name.
+        */
+        int nByte;
+        int nVar;
+        pInput->iNext++;
+        if( (rc = sessionChangesetBufferTblhdr(pInput, &nByte)) ){
+          goto finished_invert;
+        }
+        nVar = sessionVarintGet(&pInput->aData[pInput->iNext], &nCol);
+        sPK.nBuf = 0;
+        sessionAppendBlob(&sPK, &pInput->aData[pInput->iNext+nVar], nCol, &rc);
+        sessionAppendByte(&sOut, eType, &rc);
+        sessionAppendBlob(&sOut, &pInput->aData[pInput->iNext], nByte, &rc);
+        if( rc ) goto finished_invert;
+
+        pInput->iNext += nByte;
+        sqlite3_free(apVal);
+        apVal = 0;
+        abPK = sPK.aBuf;
+        break;
+      }
+
+      case SQLITE_INSERT:
+      case SQLITE_DELETE: {
+        int nByte;
+        int bIndirect = pInput->aData[pInput->iNext+1];
+        int eType2 = (eType==SQLITE_DELETE ? SQLITE_INSERT : SQLITE_DELETE);
+        pInput->iNext += 2;
+        assert( rc==SQLITE_OK );
+        rc = sessionChangesetBufferRecord(pInput, nCol, &nByte);
+        sessionAppendByte(&sOut, eType2, &rc);
+        sessionAppendByte(&sOut, bIndirect, &rc);
+        sessionAppendBlob(&sOut, &pInput->aData[pInput->iNext], nByte, &rc);
+        pInput->iNext += nByte;
+        if( rc ) goto finished_invert;
+        break;
+      }
+
+      case SQLITE_UPDATE: {
+        int iCol;
+
+        if( 0==apVal ){
+          apVal = (sqlite3_value **)sqlite3_malloc64(sizeof(apVal[0])*nCol*2);
+          if( 0==apVal ){
+            rc = SQLITE_NOMEM;
+            goto finished_invert;
+          }
+          memset(apVal, 0, sizeof(apVal[0])*nCol*2);
+        }
+
+        /* Write the header for the new UPDATE change. Same as the original. */
+        sessionAppendByte(&sOut, eType, &rc);
+        sessionAppendByte(&sOut, pInput->aData[pInput->iNext+1], &rc);
+
+        /* Read the old.* and new.* records for the update change. */
+        pInput->iNext += 2;
+        rc = sessionReadRecord(pInput, nCol, 0, &apVal[0], 0);
+        if( rc==SQLITE_OK ){
+          rc = sessionReadRecord(pInput, nCol, 0, &apVal[nCol], 0);
+        }
+
+        /* Write the new old.* record. Consists of the PK columns from the
+        ** original old.* record, and the other values from the original
+        ** new.* record. */
+        for(iCol=0; iCol<nCol; iCol++){
+          sqlite3_value *pVal = apVal[iCol + (abPK[iCol] ? 0 : nCol)];
+          sessionAppendValue(&sOut, pVal, &rc);
+        }
+
+        /* Write the new new.* record. Consists of a copy of all values
+        ** from the original old.* record, except for the PK columns, which
+        ** are set to "undefined". */
+        for(iCol=0; iCol<nCol; iCol++){
+          sqlite3_value *pVal = (abPK[iCol] ? 0 : apVal[iCol]);
+          sessionAppendValue(&sOut, pVal, &rc);
+        }
+
+        for(iCol=0; iCol<nCol*2; iCol++){
+          sqlite3ValueFree(apVal[iCol]);
+        }
+        memset(apVal, 0, sizeof(apVal[0])*nCol*2);
+        if( rc!=SQLITE_OK ){
+          goto finished_invert;
+        }
+
+        break;
+      }
+
+      default:
+        rc = SQLITE_CORRUPT_BKPT;
+        goto finished_invert;
+    }
+
+    assert( rc==SQLITE_OK );
+    if( xOutput && sOut.nBuf>=sessions_strm_chunk_size ){
+      rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
+      sOut.nBuf = 0;
+      if( rc!=SQLITE_OK ) goto finished_invert;
+    }
+  }
+
+  assert( rc==SQLITE_OK );
+  if( pnInverted && ALWAYS(ppInverted) ){
+    *pnInverted = sOut.nBuf;
+    *ppInverted = sOut.aBuf;
+    sOut.aBuf = 0;
+  }else if( sOut.nBuf>0 && ALWAYS(xOutput!=0) ){
+    rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
+  }
+
+ finished_invert:
+  sqlite3_free(sOut.aBuf);
+  sqlite3_free(apVal);
+  sqlite3_free(sPK.aBuf);
+  return rc;
+}
+
+
+/*
+** Invert a changeset object.
+*/
+SQLITE_API int sqlite3changeset_invert(
+  int nChangeset,                 /* Number of bytes in input */
+  const void *pChangeset,         /* Input changeset */
+  int *pnInverted,                /* OUT: Number of bytes in output changeset */
+  void **ppInverted               /* OUT: Inverse of pChangeset */
+){
+  SessionInput sInput;
+
+  /* Set up the input stream */
+  memset(&sInput, 0, sizeof(SessionInput));
+  sInput.nData = nChangeset;
+  sInput.aData = (u8*)pChangeset;
+
+  return sessionChangesetInvert(&sInput, 0, 0, pnInverted, ppInverted);
+}
+
+/*
+** Streaming version of sqlite3changeset_invert().
+*/
+SQLITE_API int sqlite3changeset_invert_strm(
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  SessionInput sInput;
+  int rc;
+
+  /* Set up the input stream */
+  memset(&sInput, 0, sizeof(SessionInput));
+  sInput.xInput = xInput;
+  sInput.pIn = pIn;
+
+  rc = sessionChangesetInvert(&sInput, xOutput, pOut, 0, 0);
+  sqlite3_free(sInput.buf.aBuf);
+  return rc;
+}
+
+
+typedef struct SessionUpdate SessionUpdate;
+struct SessionUpdate {
+  sqlite3_stmt *pStmt;
+  u32 *aMask;
+  SessionUpdate *pNext;
+};
+
+typedef struct SessionApplyCtx SessionApplyCtx;
+struct SessionApplyCtx {
+  sqlite3 *db;
+  sqlite3_stmt *pDelete;          /* DELETE statement */
+  sqlite3_stmt *pInsert;          /* INSERT statement */
+  sqlite3_stmt *pSelect;          /* SELECT statement */
+  int nCol;                       /* Size of azCol[] and abPK[] arrays */
+  const char **azCol;             /* Array of column names */
+  u8 *abPK;                       /* Boolean array - true if column is in PK */
+  u32 *aUpdateMask;               /* Used by sessionUpdateFind */
+  SessionUpdate *pUp;
+  int bStat1;                     /* True if table is sqlite_stat1 */
+  int bDeferConstraints;          /* True to defer constraints */
+  int bInvertConstraints;         /* Invert when iterating constraints buffer */
+  SessionBuffer constraints;      /* Deferred constraints are stored here */
+  SessionBuffer rebase;           /* Rebase information (if any) here */
+  u8 bRebaseStarted;              /* If table header is already in rebase */
+  u8 bRebase;                     /* True to collect rebase information */
+  u8 bIgnoreNoop;                 /* True to ignore no-op conflicts */
+  int bRowid;
+};
+
+/* Number of prepared UPDATE statements to cache. */
+#define SESSION_UPDATE_CACHE_SZ 12
+
+/*
+** Find a prepared UPDATE statement suitable for the UPDATE step currently
+** being visited by the iterator. The UPDATE is of the form:
+**
+**   UPDATE tbl SET col = ?, col2 = ? WHERE pk1 IS ? AND pk2 IS ?
+*/
+static int sessionUpdateFind(
+  sqlite3_changeset_iter *pIter,
+  SessionApplyCtx *p,
+  int bPatchset,
+  sqlite3_stmt **ppStmt
+){
+  int rc = SQLITE_OK;
+  SessionUpdate *pUp = 0;
+  int nCol = pIter->nCol;
+  int nU32 = (pIter->nCol+33)/32;
+  int ii;
+
+  if( p->aUpdateMask==0 ){
+    p->aUpdateMask = sqlite3_malloc(nU32*sizeof(u32));
+    if( p->aUpdateMask==0 ){
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    memset(p->aUpdateMask, 0, nU32*sizeof(u32));
+    rc = SQLITE_CORRUPT;
+    for(ii=0; ii<pIter->nCol; ii++){
+      if( sessionChangesetNew(pIter, ii) ){
+        p->aUpdateMask[ii/32] |= (1<<(ii%32));
+        rc = SQLITE_OK;
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( bPatchset ) p->aUpdateMask[nCol/32] |= (1<<(nCol%32));
+
+    if( p->pUp ){
+      int nUp = 0;
+      SessionUpdate **pp = &p->pUp;
+      while( 1 ){
+        nUp++;
+        if( 0==memcmp(p->aUpdateMask, (*pp)->aMask, nU32*sizeof(u32)) ){
+          pUp = *pp;
+          *pp = pUp->pNext;
+          pUp->pNext = p->pUp;
+          p->pUp = pUp;
+          break;
+        }
+
+        if( (*pp)->pNext ){
+          pp = &(*pp)->pNext;
+        }else{
+          if( nUp>=SESSION_UPDATE_CACHE_SZ ){
+            sqlite3_finalize((*pp)->pStmt);
+            sqlite3_free(*pp);
+            *pp = 0;
+          }
+          break;
+        }
+      }
+    }
+
+    if( pUp==0 ){
+      int nByte = sizeof(SessionUpdate) * nU32*sizeof(u32);
+      int bStat1 = (sqlite3_stricmp(pIter->zTab, "sqlite_stat1")==0);
+      pUp = (SessionUpdate*)sqlite3_malloc(nByte);
+      if( pUp==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        const char *zSep = "";
+        SessionBuffer buf;
+
+        memset(&buf, 0, sizeof(buf));
+        pUp->aMask = (u32*)&pUp[1];
+        memcpy(pUp->aMask, p->aUpdateMask, nU32*sizeof(u32));
+
+        sessionAppendStr(&buf, "UPDATE main.", &rc);
+        sessionAppendIdent(&buf, pIter->zTab, &rc);
+        sessionAppendStr(&buf, " SET ", &rc);
+
+        /* Create the assignments part of the UPDATE */
+        for(ii=0; ii<pIter->nCol; ii++){
+          if( p->abPK[ii]==0 && sessionChangesetNew(pIter, ii) ){
+            sessionAppendStr(&buf, zSep, &rc);
+            sessionAppendIdent(&buf, p->azCol[ii], &rc);
+            sessionAppendStr(&buf, " = ?", &rc);
+            sessionAppendInteger(&buf, ii*2+1, &rc);
+            zSep = ", ";
+          }
+        }
+
+        /* Create the WHERE clause part of the UPDATE */
+        zSep = "";
+        sessionAppendStr(&buf, " WHERE ", &rc);
+        for(ii=0; ii<pIter->nCol; ii++){
+          if( p->abPK[ii] || (bPatchset==0 && sessionChangesetOld(pIter, ii)) ){
+            sessionAppendStr(&buf, zSep, &rc);
+            if( bStat1 && ii==1 ){
+              assert( sqlite3_stricmp(p->azCol[ii], "idx")==0 );
+              sessionAppendStr(&buf,
+                  "idx IS CASE "
+                  "WHEN length(?4)=0 AND typeof(?4)='blob' THEN NULL "
+                  "ELSE ?4 END ", &rc
+              );
+            }else{
+              sessionAppendIdent(&buf, p->azCol[ii], &rc);
+              sessionAppendStr(&buf, " IS ?", &rc);
+              sessionAppendInteger(&buf, ii*2+2, &rc);
+            }
+            zSep = " AND ";
+          }
+        }
+
+        if( rc==SQLITE_OK ){
+          char *zSql = (char*)buf.aBuf;
+          rc = sqlite3_prepare_v2(p->db, zSql, buf.nBuf, &pUp->pStmt, 0);
+        }
+
+        if( rc!=SQLITE_OK ){
+          sqlite3_free(pUp);
+          pUp = 0;
+        }else{
+          pUp->pNext = p->pUp;
+          p->pUp = pUp;
+        }
+        sqlite3_free(buf.aBuf);
+      }
+    }
+  }
+
+  assert( (rc==SQLITE_OK)==(pUp!=0) );
+  if( pUp ){
+    *ppStmt = pUp->pStmt;
+  }else{
+    *ppStmt = 0;
+  }
+  return rc;
+}
+
+/*
+** Free all cached UPDATE statements.
+*/
+static void sessionUpdateFree(SessionApplyCtx *p){
+  SessionUpdate *pUp;
+  SessionUpdate *pNext;
+  for(pUp=p->pUp; pUp; pUp=pNext){
+    pNext = pUp->pNext;
+    sqlite3_finalize(pUp->pStmt);
+    sqlite3_free(pUp);
+  }
+  p->pUp = 0;
+  sqlite3_free(p->aUpdateMask);
+  p->aUpdateMask = 0;
+}
+
+/*
+** Formulate a statement to DELETE a row from database db. Assuming a table
+** structure like this:
+**
+**     CREATE TABLE x(a, b, c, d, PRIMARY KEY(a, c));
+**
+** The DELETE statement looks like this:
+**
+**     DELETE FROM x WHERE a = :1 AND c = :3 AND (:5 OR b IS :2 AND d IS :4)
+**
+** Variable :5 (nCol+1) is a boolean. It should be set to 0 if we require
+** matching b and d values, or 1 otherwise. The second case comes up if the
+** conflict handler is invoked with NOTFOUND and returns CHANGESET_REPLACE.
+**
+** If successful, SQLITE_OK is returned and SessionApplyCtx.pDelete is left
+** pointing to the prepared version of the SQL statement.
+*/
+static int sessionDeleteRow(
+  sqlite3 *db,                    /* Database handle */
+  const char *zTab,               /* Table name */
+  SessionApplyCtx *p              /* Session changeset-apply context */
+){
+  int i;
+  const char *zSep = "";
+  int rc = SQLITE_OK;
+  SessionBuffer buf = {0, 0, 0};
+  int nPk = 0;
+
+  sessionAppendStr(&buf, "DELETE FROM main.", &rc);
+  sessionAppendIdent(&buf, zTab, &rc);
+  sessionAppendStr(&buf, " WHERE ", &rc);
+
+  for(i=0; i<p->nCol; i++){
+    if( p->abPK[i] ){
+      nPk++;
+      sessionAppendStr(&buf, zSep, &rc);
+      sessionAppendIdent(&buf, p->azCol[i], &rc);
+      sessionAppendStr(&buf, " = ?", &rc);
+      sessionAppendInteger(&buf, i+1, &rc);
+      zSep = " AND ";
+    }
+  }
+
+  if( nPk<p->nCol ){
+    sessionAppendStr(&buf, " AND (?", &rc);
+    sessionAppendInteger(&buf, p->nCol+1, &rc);
+    sessionAppendStr(&buf, " OR ", &rc);
+
+    zSep = "";
+    for(i=0; i<p->nCol; i++){
+      if( !p->abPK[i] ){
+        sessionAppendStr(&buf, zSep, &rc);
+        sessionAppendIdent(&buf, p->azCol[i], &rc);
+        sessionAppendStr(&buf, " IS ?", &rc);
+        sessionAppendInteger(&buf, i+1, &rc);
+        zSep = "AND ";
+      }
+    }
+    sessionAppendStr(&buf, ")", &rc);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_prepare_v2(db, (char *)buf.aBuf, buf.nBuf, &p->pDelete, 0);
+  }
+  sqlite3_free(buf.aBuf);
+
+  return rc;
+}
+
+/*
+** Formulate and prepare an SQL statement to query table zTab by primary
+** key. Assuming the following table structure:
+**
+**     CREATE TABLE x(a, b, c, d, PRIMARY KEY(a, c));
+**
+** The SELECT statement looks like this:
+**
+**     SELECT * FROM x WHERE a = ?1 AND c = ?3
+**
+** If successful, SQLITE_OK is returned and SessionApplyCtx.pSelect is left
+** pointing to the prepared version of the SQL statement.
+*/
+static int sessionSelectRow(
+  sqlite3 *db,                    /* Database handle */
+  const char *zTab,               /* Table name */
+  SessionApplyCtx *p              /* Session changeset-apply context */
+){
+  /* TODO */
+  return sessionSelectStmt(db, p->bIgnoreNoop,
+      "main", zTab, p->bRowid, p->nCol, p->azCol, p->abPK, &p->pSelect
+  );
+}
+
+/*
+** Formulate and prepare an INSERT statement to add a record to table zTab.
+** For example:
+**
+**     INSERT INTO main."zTab" VALUES(?1, ?2, ?3 ...);
+**
+** If successful, SQLITE_OK is returned and SessionApplyCtx.pInsert is left
+** pointing to the prepared version of the SQL statement.
+*/
+static int sessionInsertRow(
+  sqlite3 *db,                    /* Database handle */
+  const char *zTab,               /* Table name */
+  SessionApplyCtx *p              /* Session changeset-apply context */
+){
+  int rc = SQLITE_OK;
+  int i;
+  SessionBuffer buf = {0, 0, 0};
+
+  sessionAppendStr(&buf, "INSERT INTO main.", &rc);
+  sessionAppendIdent(&buf, zTab, &rc);
+  sessionAppendStr(&buf, "(", &rc);
+  for(i=0; i<p->nCol; i++){
+    if( i!=0 ) sessionAppendStr(&buf, ", ", &rc);
+    sessionAppendIdent(&buf, p->azCol[i], &rc);
+  }
+
+  sessionAppendStr(&buf, ") VALUES(?", &rc);
+  for(i=1; i<p->nCol; i++){
+    sessionAppendStr(&buf, ", ?", &rc);
+  }
+  sessionAppendStr(&buf, ")", &rc);
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_prepare_v2(db, (char *)buf.aBuf, buf.nBuf, &p->pInsert, 0);
+  }
+  sqlite3_free(buf.aBuf);
+  return rc;
+}
+
+static int sessionPrepare(sqlite3 *db, sqlite3_stmt **pp, const char *zSql){
+  return sqlite3_prepare_v2(db, zSql, -1, pp, 0);
+}
+
+/*
+** Prepare statements for applying changes to the sqlite_stat1 table.
+** These are similar to those created by sessionSelectRow(),
+** sessionInsertRow(), sessionUpdateRow() and sessionDeleteRow() for
+** other tables.
+*/
+static int sessionStat1Sql(sqlite3 *db, SessionApplyCtx *p){
+  int rc = sessionSelectRow(db, "sqlite_stat1", p);
+  if( rc==SQLITE_OK ){
+    rc = sessionPrepare(db, &p->pInsert,
+        "INSERT INTO main.sqlite_stat1 VALUES(?1, "
+        "CASE WHEN length(?2)=0 AND typeof(?2)='blob' THEN NULL ELSE ?2 END, "
+        "?3)"
+    );
+  }
+  if( rc==SQLITE_OK ){
+    rc = sessionPrepare(db, &p->pDelete,
+        "DELETE FROM main.sqlite_stat1 WHERE tbl=?1 AND idx IS "
+        "CASE WHEN length(?2)=0 AND typeof(?2)='blob' THEN NULL ELSE ?2 END "
+        "AND (?4 OR stat IS ?3)"
+    );
+  }
+  return rc;
+}
+
+/*
+** A wrapper around sqlite3_bind_value() that detects an extra problem.
+** See comments in the body of this function for details.
+*/
+static int sessionBindValue(
+  sqlite3_stmt *pStmt,            /* Statement to bind value to */
+  int i,                          /* Parameter number to bind to */
+  sqlite3_value *pVal             /* Value to bind */
+){
+  int eType = sqlite3_value_type(pVal);
+  /* COVERAGE: The (pVal->z==0) branch is never true using current versions
+  ** of SQLite. If a malloc fails in an sqlite3_value_xxx() function, either
+  ** the (pVal->z) variable remains as it was or the type of the value is
+  ** set to SQLITE_NULL.  */
+  if( (eType==SQLITE_TEXT || eType==SQLITE_BLOB) && pVal->z==0 ){
+    /* This condition occurs when an earlier OOM in a call to
+    ** sqlite3_value_text() or sqlite3_value_blob() (perhaps from within
+    ** a conflict-handler) has zeroed the pVal->z pointer. Return NOMEM. */
+    return SQLITE_NOMEM;
+  }
+  return sqlite3_bind_value(pStmt, i, pVal);
+}
+
+/*
+** Iterator pIter must point to an SQLITE_INSERT entry. This function
+** transfers new.* values from the current iterator entry to statement
+** pStmt. The table being inserted into has nCol columns.
+**
+** New.* value $i from the iterator is bound to variable ($i+1) of
+** statement pStmt. If parameter abPK is NULL, all values from 0 to (nCol-1)
+** are transfered to the statement. Otherwise, if abPK is not NULL, it points
+** to an array nCol elements in size. In this case only those values for
+** which abPK[$i] is true are read from the iterator and bound to the
+** statement.
+**
+** An SQLite error code is returned if an error occurs. Otherwise, SQLITE_OK.
+*/
+static int sessionBindRow(
+  sqlite3_changeset_iter *pIter,  /* Iterator to read values from */
+  int(*xValue)(sqlite3_changeset_iter *, int, sqlite3_value **),
+  int nCol,                       /* Number of columns */
+  u8 *abPK,                       /* If not NULL, bind only if true */
+  sqlite3_stmt *pStmt             /* Bind values to this statement */
+){
+  int i;
+  int rc = SQLITE_OK;
+
+  /* Neither sqlite3changeset_old or sqlite3changeset_new can fail if the
+  ** argument iterator points to a suitable entry. Make sure that xValue
+  ** is one of these to guarantee that it is safe to ignore the return
+  ** in the code below. */
+  assert( xValue==sqlite3changeset_old || xValue==sqlite3changeset_new );
+
+  for(i=0; rc==SQLITE_OK && i<nCol; i++){
+    if( !abPK || abPK[i] ){
+      sqlite3_value *pVal = 0;
+      (void)xValue(pIter, i, &pVal);
+      if( pVal==0 ){
+        /* The value in the changeset was "undefined". This indicates a
+        ** corrupt changeset blob.  */
+        rc = SQLITE_CORRUPT_BKPT;
+      }else{
+        rc = sessionBindValue(pStmt, i+1, pVal);
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** SQL statement pSelect is as generated by the sessionSelectRow() function.
+** This function binds the primary key values from the change that changeset
+** iterator pIter points to to the SELECT and attempts to seek to the table
+** entry. If a row is found, the SELECT statement left pointing at the row
+** and SQLITE_ROW is returned. Otherwise, if no row is found and no error
+** has occured, the statement is reset and SQLITE_OK is returned. If an
+** error occurs, the statement is reset and an SQLite error code is returned.
+**
+** If this function returns SQLITE_ROW, the caller must eventually reset()
+** statement pSelect. If any other value is returned, the statement does
+** not require a reset().
+**
+** If the iterator currently points to an INSERT record, bind values from the
+** new.* record to the SELECT statement. Or, if it points to a DELETE or
+** UPDATE, bind values from the old.* record.
+*/
+static int sessionSeekToRow(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  SessionApplyCtx *p
+){
+  sqlite3_stmt *pSelect = p->pSelect;
+  int rc;                         /* Return code */
+  int nCol;                       /* Number of columns in table */
+  int op;                         /* Changset operation (SQLITE_UPDATE etc.) */
+  const char *zDummy;             /* Unused */
+
+  sqlite3_clear_bindings(pSelect);
+  sqlite3changeset_op(pIter, &zDummy, &nCol, &op, 0);
+  rc = sessionBindRow(pIter,
+      op==SQLITE_INSERT ? sqlite3changeset_new : sqlite3changeset_old,
+      nCol, p->abPK, pSelect
+  );
+
+  if( op!=SQLITE_DELETE && p->bIgnoreNoop ){
+    int ii;
+    for(ii=0; rc==SQLITE_OK && ii<nCol; ii++){
+      if( p->abPK[ii]==0 ){
+        sqlite3_value *pVal = 0;
+        sqlite3changeset_new(pIter, ii, &pVal);
+        sqlite3_bind_int(pSelect, ii+1+nCol, (pVal==0));
+        if( pVal ) rc = sessionBindValue(pSelect, ii+1, pVal);
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_step(pSelect);
+    if( rc!=SQLITE_ROW ) rc = sqlite3_reset(pSelect);
+  }
+
+  return rc;
+}
+
+/*
+** This function is called from within sqlite3changeset_apply_v2() when
+** a conflict is encountered and resolved using conflict resolution
+** mode eType (either SQLITE_CHANGESET_OMIT or SQLITE_CHANGESET_REPLACE)..
+** It adds a conflict resolution record to the buffer in
+** SessionApplyCtx.rebase, which will eventually be returned to the caller
+** of apply_v2() as the "rebase" buffer.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise.
+*/
+static int sessionRebaseAdd(
+  SessionApplyCtx *p,             /* Apply context */
+  int eType,                      /* Conflict resolution (OMIT or REPLACE) */
+  sqlite3_changeset_iter *pIter   /* Iterator pointing at current change */
+){
+  int rc = SQLITE_OK;
+  if( p->bRebase ){
+    int i;
+    int eOp = pIter->op;
+    if( p->bRebaseStarted==0 ){
+      /* Append a table-header to the rebase buffer */
+      const char *zTab = pIter->zTab;
+      sessionAppendByte(&p->rebase, 'T', &rc);
+      sessionAppendVarint(&p->rebase, p->nCol, &rc);
+      sessionAppendBlob(&p->rebase, p->abPK, p->nCol, &rc);
+      sessionAppendBlob(&p->rebase, (u8*)zTab, (int)strlen(zTab)+1, &rc);
+      p->bRebaseStarted = 1;
+    }
+
+    assert( eType==SQLITE_CHANGESET_REPLACE||eType==SQLITE_CHANGESET_OMIT );
+    assert( eOp==SQLITE_DELETE || eOp==SQLITE_INSERT || eOp==SQLITE_UPDATE );
+
+    sessionAppendByte(&p->rebase,
+        (eOp==SQLITE_DELETE ? SQLITE_DELETE : SQLITE_INSERT), &rc
+        );
+    sessionAppendByte(&p->rebase, (eType==SQLITE_CHANGESET_REPLACE), &rc);
+    for(i=0; i<p->nCol; i++){
+      sqlite3_value *pVal = 0;
+      if( eOp==SQLITE_DELETE || (eOp==SQLITE_UPDATE && p->abPK[i]) ){
+        sqlite3changeset_old(pIter, i, &pVal);
+      }else{
+        sqlite3changeset_new(pIter, i, &pVal);
+      }
+      sessionAppendValue(&p->rebase, pVal, &rc);
+    }
+  }
+  return rc;
+}
+
+/*
+** Invoke the conflict handler for the change that the changeset iterator
+** currently points to.
+**
+** Argument eType must be either CHANGESET_DATA or CHANGESET_CONFLICT.
+** If argument pbReplace is NULL, then the type of conflict handler invoked
+** depends solely on eType, as follows:
+**
+**    eType value                 Value passed to xConflict
+**    -------------------------------------------------
+**    CHANGESET_DATA              CHANGESET_NOTFOUND
+**    CHANGESET_CONFLICT          CHANGESET_CONSTRAINT
+**
+** Or, if pbReplace is not NULL, then an attempt is made to find an existing
+** record with the same primary key as the record about to be deleted, updated
+** or inserted. If such a record can be found, it is available to the conflict
+** handler as the "conflicting" record. In this case the type of conflict
+** handler invoked is as follows:
+**
+**    eType value         PK Record found?   Value passed to xConflict
+**    ----------------------------------------------------------------
+**    CHANGESET_DATA      Yes                CHANGESET_DATA
+**    CHANGESET_DATA      No                 CHANGESET_NOTFOUND
+**    CHANGESET_CONFLICT  Yes                CHANGESET_CONFLICT
+**    CHANGESET_CONFLICT  No                 CHANGESET_CONSTRAINT
+**
+** If pbReplace is not NULL, and a record with a matching PK is found, and
+** the conflict handler function returns SQLITE_CHANGESET_REPLACE, *pbReplace
+** is set to non-zero before returning SQLITE_OK.
+**
+** If the conflict handler returns SQLITE_CHANGESET_ABORT, SQLITE_ABORT is
+** returned. Or, if the conflict handler returns an invalid value,
+** SQLITE_MISUSE. If the conflict handler returns SQLITE_CHANGESET_OMIT,
+** this function returns SQLITE_OK.
+*/
+static int sessionConflictHandler(
+  int eType,                      /* Either CHANGESET_DATA or CONFLICT */
+  SessionApplyCtx *p,             /* changeset_apply() context */
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int(*xConflict)(void *, int, sqlite3_changeset_iter*),
+  void *pCtx,                     /* First argument for conflict handler */
+  int *pbReplace                  /* OUT: Set to true if PK row is found */
+){
+  int res = 0;                    /* Value returned by conflict handler */
+  int rc;
+  int nCol;
+  int op;
+  const char *zDummy;
+
+  sqlite3changeset_op(pIter, &zDummy, &nCol, &op, 0);
+
+  assert( eType==SQLITE_CHANGESET_CONFLICT || eType==SQLITE_CHANGESET_DATA );
+  assert( SQLITE_CHANGESET_CONFLICT+1==SQLITE_CHANGESET_CONSTRAINT );
+  assert( SQLITE_CHANGESET_DATA+1==SQLITE_CHANGESET_NOTFOUND );
+
+  /* Bind the new.* PRIMARY KEY values to the SELECT statement. */
+  if( pbReplace ){
+    rc = sessionSeekToRow(pIter, p);
+  }else{
+    rc = SQLITE_OK;
+  }
+
+  if( rc==SQLITE_ROW ){
+    /* There exists another row with the new.* primary key. */
+    if( p->bIgnoreNoop
+     && sqlite3_column_int(p->pSelect, sqlite3_column_count(p->pSelect)-1)
+    ){
+      res = SQLITE_CHANGESET_OMIT;
+    }else{
+      pIter->pConflict = p->pSelect;
+      res = xConflict(pCtx, eType, pIter);
+      pIter->pConflict = 0;
+    }
+    rc = sqlite3_reset(p->pSelect);
+  }else if( rc==SQLITE_OK ){
+    if( p->bDeferConstraints && eType==SQLITE_CHANGESET_CONFLICT ){
+      /* Instead of invoking the conflict handler, append the change blob
+      ** to the SessionApplyCtx.constraints buffer. */
+      u8 *aBlob = &pIter->in.aData[pIter->in.iCurrent];
+      int nBlob = pIter->in.iNext - pIter->in.iCurrent;
+      sessionAppendBlob(&p->constraints, aBlob, nBlob, &rc);
+      return SQLITE_OK;
+    }else{
+      /* No other row with the new.* primary key. */
+      res = xConflict(pCtx, eType+1, pIter);
+      if( res==SQLITE_CHANGESET_REPLACE ) rc = SQLITE_MISUSE;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    switch( res ){
+      case SQLITE_CHANGESET_REPLACE:
+        assert( pbReplace );
+        *pbReplace = 1;
+        break;
+
+      case SQLITE_CHANGESET_OMIT:
+        break;
+
+      case SQLITE_CHANGESET_ABORT:
+        rc = SQLITE_ABORT;
+        break;
+
+      default:
+        rc = SQLITE_MISUSE;
+        break;
+    }
+    if( rc==SQLITE_OK ){
+      rc = sessionRebaseAdd(p, res, pIter);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Attempt to apply the change that the iterator passed as the first argument
+** currently points to to the database. If a conflict is encountered, invoke
+** the conflict handler callback.
+**
+** If argument pbRetry is NULL, then ignore any CHANGESET_DATA conflict. If
+** one is encountered, update or delete the row with the matching primary key
+** instead. Or, if pbRetry is not NULL and a CHANGESET_DATA conflict occurs,
+** invoke the conflict handler. If it returns CHANGESET_REPLACE, set *pbRetry
+** to true before returning. In this case the caller will invoke this function
+** again, this time with pbRetry set to NULL.
+**
+** If argument pbReplace is NULL and a CHANGESET_CONFLICT conflict is
+** encountered invoke the conflict handler with CHANGESET_CONSTRAINT instead.
+** Or, if pbReplace is not NULL, invoke it with CHANGESET_CONFLICT. If such
+** an invocation returns SQLITE_CHANGESET_REPLACE, set *pbReplace to true
+** before retrying. In this case the caller attempts to remove the conflicting
+** row before invoking this function again, this time with pbReplace set
+** to NULL.
+**
+** If any conflict handler returns SQLITE_CHANGESET_ABORT, this function
+** returns SQLITE_ABORT. Otherwise, if no error occurs, SQLITE_OK is
+** returned.
+*/
+static int sessionApplyOneOp(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  SessionApplyCtx *p,             /* changeset_apply() context */
+  int(*xConflict)(void *, int, sqlite3_changeset_iter *),
+  void *pCtx,                     /* First argument for the conflict handler */
+  int *pbReplace,                 /* OUT: True to remove PK row and retry */
+  int *pbRetry                    /* OUT: True to retry. */
+){
+  const char *zDummy;
+  int op;
+  int nCol;
+  int rc = SQLITE_OK;
+
+  assert( p->pDelete && p->pInsert && p->pSelect );
+  assert( p->azCol && p->abPK );
+  assert( !pbReplace || *pbReplace==0 );
+
+  sqlite3changeset_op(pIter, &zDummy, &nCol, &op, 0);
+
+  if( op==SQLITE_DELETE ){
+
+    /* Bind values to the DELETE statement. If conflict handling is required,
+    ** bind values for all columns and set bound variable (nCol+1) to true.
+    ** Or, if conflict handling is not required, bind just the PK column
+    ** values and, if it exists, set (nCol+1) to false. Conflict handling
+    ** is not required if:
+    **
+    **   * this is a patchset, or
+    **   * (pbRetry==0), or
+    **   * all columns of the table are PK columns (in this case there is
+    **     no (nCol+1) variable to bind to).
+    */
+    u8 *abPK = (pIter->bPatchset ? p->abPK : 0);
+    rc = sessionBindRow(pIter, sqlite3changeset_old, nCol, abPK, p->pDelete);
+    if( rc==SQLITE_OK && sqlite3_bind_parameter_count(p->pDelete)>nCol ){
+      rc = sqlite3_bind_int(p->pDelete, nCol+1, (pbRetry==0 || abPK));
+    }
+    if( rc!=SQLITE_OK ) return rc;
+
+    sqlite3_step(p->pDelete);
+    rc = sqlite3_reset(p->pDelete);
+    if( rc==SQLITE_OK && sqlite3_changes(p->db)==0 && p->bIgnoreNoop==0 ){
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_DATA, p, pIter, xConflict, pCtx, pbRetry
+      );
+    }else if( (rc&0xff)==SQLITE_CONSTRAINT ){
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_CONFLICT, p, pIter, xConflict, pCtx, 0
+      );
+    }
+
+  }else if( op==SQLITE_UPDATE ){
+    int i;
+    sqlite3_stmt *pUp = 0;
+    int bPatchset = (pbRetry==0 || pIter->bPatchset);
+
+    rc = sessionUpdateFind(pIter, p, bPatchset, &pUp);
+
+    /* Bind values to the UPDATE statement. */
+    for(i=0; rc==SQLITE_OK && i<nCol; i++){
+      sqlite3_value *pOld = sessionChangesetOld(pIter, i);
+      sqlite3_value *pNew = sessionChangesetNew(pIter, i);
+      if( p->abPK[i] || (bPatchset==0 && pOld) ){
+        rc = sessionBindValue(pUp, i*2+2, pOld);
+      }
+      if( rc==SQLITE_OK && pNew ){
+        rc = sessionBindValue(pUp, i*2+1, pNew);
+      }
+    }
+    if( rc!=SQLITE_OK ) return rc;
+
+    /* Attempt the UPDATE. In the case of a NOTFOUND or DATA conflict,
+    ** the result will be SQLITE_OK with 0 rows modified. */
+    sqlite3_step(pUp);
+    rc = sqlite3_reset(pUp);
+
+    if( rc==SQLITE_OK && sqlite3_changes(p->db)==0 ){
+      /* A NOTFOUND or DATA error. Search the table to see if it contains
+      ** a row with a matching primary key. If so, this is a DATA conflict.
+      ** Otherwise, if there is no primary key match, it is a NOTFOUND. */
+
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_DATA, p, pIter, xConflict, pCtx, pbRetry
+      );
+
+    }else if( (rc&0xff)==SQLITE_CONSTRAINT ){
+      /* This is always a CONSTRAINT conflict. */
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_CONFLICT, p, pIter, xConflict, pCtx, 0
+      );
+    }
+
+  }else{
+    assert( op==SQLITE_INSERT );
+    if( p->bStat1 ){
+      /* Check if there is a conflicting row. For sqlite_stat1, this needs
+      ** to be done using a SELECT, as there is no PRIMARY KEY in the
+      ** database schema to throw an exception if a duplicate is inserted.  */
+      rc = sessionSeekToRow(pIter, p);
+      if( rc==SQLITE_ROW ){
+        rc = SQLITE_CONSTRAINT;
+        sqlite3_reset(p->pSelect);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = sessionBindRow(pIter, sqlite3changeset_new, nCol, 0, p->pInsert);
+      if( rc!=SQLITE_OK ) return rc;
+
+      sqlite3_step(p->pInsert);
+      rc = sqlite3_reset(p->pInsert);
+    }
+
+    if( (rc&0xff)==SQLITE_CONSTRAINT ){
+      rc = sessionConflictHandler(
+          SQLITE_CHANGESET_CONFLICT, p, pIter, xConflict, pCtx, pbReplace
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Attempt to apply the change that the iterator passed as the first argument
+** currently points to to the database. If a conflict is encountered, invoke
+** the conflict handler callback.
+**
+** The difference between this function and sessionApplyOne() is that this
+** function handles the case where the conflict-handler is invoked and
+** returns SQLITE_CHANGESET_REPLACE - indicating that the change should be
+** retried in some manner.
+*/
+static int sessionApplyOneWithRetry(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator to read change from */
+  SessionApplyCtx *pApply,        /* Apply context */
+  int(*xConflict)(void*, int, sqlite3_changeset_iter*),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  int bReplace = 0;
+  int bRetry = 0;
+  int rc;
+
+  rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, &bReplace, &bRetry);
+  if( rc==SQLITE_OK ){
+    /* If the bRetry flag is set, the change has not been applied due to an
+    ** SQLITE_CHANGESET_DATA problem (i.e. this is an UPDATE or DELETE and
+    ** a row with the correct PK is present in the db, but one or more other
+    ** fields do not contain the expected values) and the conflict handler
+    ** returned SQLITE_CHANGESET_REPLACE. In this case retry the operation,
+    ** but pass NULL as the final argument so that sessionApplyOneOp() ignores
+    ** the SQLITE_CHANGESET_DATA problem.  */
+    if( bRetry ){
+      assert( pIter->op==SQLITE_UPDATE || pIter->op==SQLITE_DELETE );
+      rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, 0, 0);
+    }
+
+    /* If the bReplace flag is set, the change is an INSERT that has not
+    ** been performed because the database already contains a row with the
+    ** specified primary key and the conflict handler returned
+    ** SQLITE_CHANGESET_REPLACE. In this case remove the conflicting row
+    ** before reattempting the INSERT.  */
+    else if( bReplace ){
+      assert( pIter->op==SQLITE_INSERT );
+      rc = sqlite3_exec(db, "SAVEPOINT replace_op", 0, 0, 0);
+      if( rc==SQLITE_OK ){
+        rc = sessionBindRow(pIter,
+            sqlite3changeset_new, pApply->nCol, pApply->abPK, pApply->pDelete);
+        sqlite3_bind_int(pApply->pDelete, pApply->nCol+1, 1);
+      }
+      if( rc==SQLITE_OK ){
+        sqlite3_step(pApply->pDelete);
+        rc = sqlite3_reset(pApply->pDelete);
+      }
+      if( rc==SQLITE_OK ){
+        rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, 0, 0);
+      }
+      if( rc==SQLITE_OK ){
+        rc = sqlite3_exec(db, "RELEASE replace_op", 0, 0, 0);
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Retry the changes accumulated in the pApply->constraints buffer.
+*/
+static int sessionRetryConstraints(
+  sqlite3 *db,
+  int bPatchset,
+  const char *zTab,
+  SessionApplyCtx *pApply,
+  int(*xConflict)(void*, int, sqlite3_changeset_iter*),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  int rc = SQLITE_OK;
+
+  while( pApply->constraints.nBuf ){
+    sqlite3_changeset_iter *pIter2 = 0;
+    SessionBuffer cons = pApply->constraints;
+    memset(&pApply->constraints, 0, sizeof(SessionBuffer));
+
+    rc = sessionChangesetStart(
+        &pIter2, 0, 0, cons.nBuf, cons.aBuf, pApply->bInvertConstraints, 1
+    );
+    if( rc==SQLITE_OK ){
+      size_t nByte = 2*pApply->nCol*sizeof(sqlite3_value*);
+      int rc2;
+      pIter2->bPatchset = bPatchset;
+      pIter2->zTab = (char*)zTab;
+      pIter2->nCol = pApply->nCol;
+      pIter2->abPK = pApply->abPK;
+      sessionBufferGrow(&pIter2->tblhdr, nByte, &rc);
+      pIter2->apValue = (sqlite3_value**)pIter2->tblhdr.aBuf;
+      if( rc==SQLITE_OK ) memset(pIter2->apValue, 0, nByte);
+
+      while( rc==SQLITE_OK && SQLITE_ROW==sqlite3changeset_next(pIter2) ){
+        rc = sessionApplyOneWithRetry(db, pIter2, pApply, xConflict, pCtx);
+      }
+
+      rc2 = sqlite3changeset_finalize(pIter2);
+      if( rc==SQLITE_OK ) rc = rc2;
+    }
+    assert( pApply->bDeferConstraints || pApply->constraints.nBuf==0 );
+
+    sqlite3_free(cons.aBuf);
+    if( rc!=SQLITE_OK ) break;
+    if( pApply->constraints.nBuf>=cons.nBuf ){
+      /* No progress was made on the last round. */
+      pApply->bDeferConstraints = 0;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Argument pIter is a changeset iterator that has been initialized, but
+** not yet passed to sqlite3changeset_next(). This function applies the
+** changeset to the main database attached to handle "db". The supplied
+** conflict handler callback is invoked to resolve any conflicts encountered
+** while applying the change.
+*/
+static int sessionChangesetApply(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  sqlite3_changeset_iter *pIter,  /* Changeset to apply */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of fifth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase, /* OUT: Rebase information */
+  int flags                       /* SESSION_APPLY_XXX flags */
+){
+  int schemaMismatch = 0;
+  int rc = SQLITE_OK;             /* Return code */
+  const char *zTab = 0;           /* Name of current table */
+  int nTab = 0;                   /* Result of sqlite3Strlen30(zTab) */
+  SessionApplyCtx sApply;         /* changeset_apply() context object */
+  int bPatchset;
+  u64 savedFlag = db->flags & SQLITE_FkNoAction;
+
+  assert( xConflict!=0 );
+
+  sqlite3_mutex_enter(sqlite3_db_mutex(db));
+  if( flags & SQLITE_CHANGESETAPPLY_FKNOACTION ){
+    db->flags |= ((u64)SQLITE_FkNoAction);
+    db->aDb[0].pSchema->schema_cookie -= 32;
+  }
+
+  pIter->in.bNoDiscard = 1;
+  memset(&sApply, 0, sizeof(sApply));
+  sApply.bRebase = (ppRebase && pnRebase);
+  sApply.bInvertConstraints = !!(flags & SQLITE_CHANGESETAPPLY_INVERT);
+  sApply.bIgnoreNoop = !!(flags & SQLITE_CHANGESETAPPLY_IGNORENOOP);
+  if( (flags & SQLITE_CHANGESETAPPLY_NOSAVEPOINT)==0 ){
+    rc = sqlite3_exec(db, "SAVEPOINT changeset_apply", 0, 0, 0);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_exec(db, "PRAGMA defer_foreign_keys = 1", 0, 0, 0);
+  }
+  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3changeset_next(pIter) ){
+    int nCol;
+    int op;
+    const char *zNew;
+
+    sqlite3changeset_op(pIter, &zNew, &nCol, &op, 0);
+
+    if( zTab==0 || sqlite3_strnicmp(zNew, zTab, nTab+1) ){
+      u8 *abPK;
+
+      rc = sessionRetryConstraints(
+          db, pIter->bPatchset, zTab, &sApply, xConflict, pCtx
+      );
+      if( rc!=SQLITE_OK ) break;
+
+      sessionUpdateFree(&sApply);
+      sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
+      sqlite3_finalize(sApply.pDelete);
+      sqlite3_finalize(sApply.pInsert);
+      sqlite3_finalize(sApply.pSelect);
+      sApply.db = db;
+      sApply.pDelete = 0;
+      sApply.pInsert = 0;
+      sApply.pSelect = 0;
+      sApply.nCol = 0;
+      sApply.azCol = 0;
+      sApply.abPK = 0;
+      sApply.bStat1 = 0;
+      sApply.bDeferConstraints = 1;
+      sApply.bRebaseStarted = 0;
+      sApply.bRowid = 0;
+      memset(&sApply.constraints, 0, sizeof(SessionBuffer));
+
+      /* If an xFilter() callback was specified, invoke it now. If the
+      ** xFilter callback returns zero, skip this table. If it returns
+      ** non-zero, proceed. */
+      schemaMismatch = (xFilter && (0==xFilter(pCtx, zNew)));
+      if( schemaMismatch ){
+        zTab = sqlite3_mprintf("%s", zNew);
+        if( zTab==0 ){
+          rc = SQLITE_NOMEM;
+          break;
+        }
+        nTab = (int)strlen(zTab);
+        sApply.azCol = (const char **)zTab;
+      }else{
+        int nMinCol = 0;
+        int i;
+
+        sqlite3changeset_pk(pIter, &abPK, 0);
+        rc = sessionTableInfo(0, db, "main", zNew,
+            &sApply.nCol, 0, &zTab, &sApply.azCol, 0, 0,
+            &sApply.abPK, &sApply.bRowid
+        );
+        if( rc!=SQLITE_OK ) break;
+        for(i=0; i<sApply.nCol; i++){
+          if( sApply.abPK[i] ) nMinCol = i+1;
+        }
+
+        if( sApply.nCol==0 ){
+          schemaMismatch = 1;
+          sqlite3_log(SQLITE_SCHEMA,
+              "sqlite3changeset_apply(): no such table: %s", zTab
+          );
+        }
+        else if( sApply.nCol<nCol ){
+          schemaMismatch = 1;
+          sqlite3_log(SQLITE_SCHEMA,
+              "sqlite3changeset_apply(): table %s has %d columns, "
+              "expected %d or more",
+              zTab, sApply.nCol, nCol
+          );
+        }
+        else if( nCol<nMinCol || memcmp(sApply.abPK, abPK, nCol)!=0 ){
+          schemaMismatch = 1;
+          sqlite3_log(SQLITE_SCHEMA, "sqlite3changeset_apply(): "
+              "primary key mismatch for table %s", zTab
+          );
+        }
+        else{
+          sApply.nCol = nCol;
+          if( 0==sqlite3_stricmp(zTab, "sqlite_stat1") ){
+            if( (rc = sessionStat1Sql(db, &sApply) ) ){
+              break;
+            }
+            sApply.bStat1 = 1;
+          }else{
+            if( (rc = sessionSelectRow(db, zTab, &sApply))
+             || (rc = sessionDeleteRow(db, zTab, &sApply))
+             || (rc = sessionInsertRow(db, zTab, &sApply))
+            ){
+              break;
+            }
+            sApply.bStat1 = 0;
+          }
+        }
+        nTab = sqlite3Strlen30(zTab);
+      }
+    }
+
+    /* If there is a schema mismatch on the current table, proceed to the
+    ** next change. A log message has already been issued. */
+    if( schemaMismatch ) continue;
+
+    rc = sessionApplyOneWithRetry(db, pIter, &sApply, xConflict, pCtx);
+  }
+
+  bPatchset = pIter->bPatchset;
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changeset_finalize(pIter);
+  }else{
+    sqlite3changeset_finalize(pIter);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sessionRetryConstraints(db, bPatchset, zTab, &sApply, xConflict, pCtx);
+  }
+
+  if( rc==SQLITE_OK ){
+    int nFk, notUsed;
+    sqlite3_db_status(db, SQLITE_DBSTATUS_DEFERRED_FKS, &nFk, ¬Used, 0);
+    if( nFk!=0 ){
+      int res = SQLITE_CHANGESET_ABORT;
+      sqlite3_changeset_iter sIter;
+      memset(&sIter, 0, sizeof(sIter));
+      sIter.nCol = nFk;
+      res = xConflict(pCtx, SQLITE_CHANGESET_FOREIGN_KEY, &sIter);
+      if( res!=SQLITE_CHANGESET_OMIT ){
+        rc = SQLITE_CONSTRAINT;
+      }
+    }
+  }
+
+  {
+    int rc2 = sqlite3_exec(db, "PRAGMA defer_foreign_keys = 0", 0, 0, 0);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+
+  if( (flags & SQLITE_CHANGESETAPPLY_NOSAVEPOINT)==0 ){
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3_exec(db, "ROLLBACK TO changeset_apply", 0, 0, 0);
+      sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
+    }
+  }
+
+  assert( sApply.bRebase || sApply.rebase.nBuf==0 );
+  if( rc==SQLITE_OK && bPatchset==0 && sApply.bRebase ){
+    *ppRebase = (void*)sApply.rebase.aBuf;
+    *pnRebase = sApply.rebase.nBuf;
+    sApply.rebase.aBuf = 0;
+  }
+  sessionUpdateFree(&sApply);
+  sqlite3_finalize(sApply.pInsert);
+  sqlite3_finalize(sApply.pDelete);
+  sqlite3_finalize(sApply.pSelect);
+  sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
+  sqlite3_free((char*)sApply.constraints.aBuf);
+  sqlite3_free((char*)sApply.rebase.aBuf);
+
+  if( (flags & SQLITE_CHANGESETAPPLY_FKNOACTION) && savedFlag==0 ){
+    assert( db->flags & SQLITE_FkNoAction );
+    db->flags &= ~((u64)SQLITE_FkNoAction);
+    db->aDb[0].pSchema->schema_cookie -= 32;
+  }
+  sqlite3_mutex_leave(sqlite3_db_mutex(db));
+  return rc;
+}
+
+/*
+** Apply the changeset passed via pChangeset/nChangeset to the main
+** database attached to handle "db".
+*/
+SQLITE_API int sqlite3changeset_apply_v2(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase,
+  int flags
+){
+  sqlite3_changeset_iter *pIter;  /* Iterator to skip through changeset */
+  int bInv = !!(flags & SQLITE_CHANGESETAPPLY_INVERT);
+  int rc = sessionChangesetStart(&pIter, 0, 0, nChangeset, pChangeset, bInv, 1);
+
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetApply(
+        db, pIter, xFilter, xConflict, pCtx, ppRebase, pnRebase, flags
+    );
+  }
+
+  return rc;
+}
+
+/*
+** Apply the changeset passed via pChangeset/nChangeset to the main database
+** attached to handle "db". Invoke the supplied conflict handler callback
+** to resolve any conflicts encountered while applying the change.
+*/
+SQLITE_API int sqlite3changeset_apply(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of fifth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  return sqlite3changeset_apply_v2(
+      db, nChangeset, pChangeset, xFilter, xConflict, pCtx, 0, 0, 0
+  );
+}
+
+/*
+** Apply the changeset passed via xInput/pIn to the main database
+** attached to handle "db". Invoke the supplied conflict handler callback
+** to resolve any conflicts encountered while applying the change.
+*/
+SQLITE_API int sqlite3changeset_apply_v2_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase,
+  int flags
+){
+  sqlite3_changeset_iter *pIter;  /* Iterator to skip through changeset */
+  int bInverse = !!(flags & SQLITE_CHANGESETAPPLY_INVERT);
+  int rc = sessionChangesetStart(&pIter, xInput, pIn, 0, 0, bInverse, 1);
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetApply(
+        db, pIter, xFilter, xConflict, pCtx, ppRebase, pnRebase, flags
+    );
+  }
+  return rc;
+}
+SQLITE_API int sqlite3changeset_apply_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+){
+  return sqlite3changeset_apply_v2_strm(
+      db, xInput, pIn, xFilter, xConflict, pCtx, 0, 0, 0
+  );
+}
+
+/*
+** sqlite3_changegroup handle.
+*/
+struct sqlite3_changegroup {
+  int rc;                         /* Error code */
+  int bPatch;                     /* True to accumulate patchsets */
+  SessionTable *pList;            /* List of tables in current patch */
+  SessionBuffer rec;
+
+  sqlite3 *db;                    /* Configured by changegroup_schema() */
+  char *zDb;                      /* Configured by changegroup_schema() */
+};
+
+/*
+** This function is called to merge two changes to the same row together as
+** part of an sqlite3changeset_concat() operation. A new change object is
+** allocated and a pointer to it stored in *ppNew.
+*/
+static int sessionChangeMerge(
+  SessionTable *pTab,             /* Table structure */
+  int bRebase,                    /* True for a rebase hash-table */
+  int bPatchset,                  /* True for patchsets */
+  SessionChange *pExist,          /* Existing change */
+  int op2,                        /* Second change operation */
+  int bIndirect,                  /* True if second change is indirect */
+  u8 *aRec,                       /* Second change record */
+  int nRec,                       /* Number of bytes in aRec */
+  SessionChange **ppNew           /* OUT: Merged change */
+){
+  SessionChange *pNew = 0;
+  int rc = SQLITE_OK;
+  assert( aRec!=0 );
+
+  if( !pExist ){
+    pNew = (SessionChange *)sqlite3_malloc64(sizeof(SessionChange) + nRec);
+    if( !pNew ){
+      return SQLITE_NOMEM;
+    }
+    memset(pNew, 0, sizeof(SessionChange));
+    pNew->op = op2;
+    pNew->bIndirect = bIndirect;
+    pNew->aRecord = (u8*)&pNew[1];
+    if( bIndirect==0 || bRebase==0 ){
+      pNew->nRecord = nRec;
+      memcpy(pNew->aRecord, aRec, nRec);
+    }else{
+      int i;
+      u8 *pIn = aRec;
+      u8 *pOut = pNew->aRecord;
+      for(i=0; i<pTab->nCol; i++){
+        int nIn = sessionSerialLen(pIn);
+        if( *pIn==0 ){
+          *pOut++ = 0;
+        }else if( pTab->abPK[i]==0 ){
+          *pOut++ = 0xFF;
+        }else{
+          memcpy(pOut, pIn, nIn);
+          pOut += nIn;
+        }
+        pIn += nIn;
+      }
+      pNew->nRecord = pOut - pNew->aRecord;
+    }
+  }else if( bRebase ){
+    if( pExist->op==SQLITE_DELETE && pExist->bIndirect ){
+      *ppNew = pExist;
+    }else{
+      sqlite3_int64 nByte = nRec + pExist->nRecord + sizeof(SessionChange);
+      pNew = (SessionChange*)sqlite3_malloc64(nByte);
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        int i;
+        u8 *a1 = pExist->aRecord;
+        u8 *a2 = aRec;
+        u8 *pOut;
+
+        memset(pNew, 0, nByte);
+        pNew->bIndirect = bIndirect || pExist->bIndirect;
+        pNew->op = op2;
+        pOut = pNew->aRecord = (u8*)&pNew[1];
+
+        for(i=0; i<pTab->nCol; i++){
+          int n1 = sessionSerialLen(a1);
+          int n2 = sessionSerialLen(a2);
+          if( *a1==0xFF || (pTab->abPK[i]==0 && bIndirect) ){
+            *pOut++ = 0xFF;
+          }else if( *a2==0 ){
+            memcpy(pOut, a1, n1);
+            pOut += n1;
+          }else{
+            memcpy(pOut, a2, n2);
+            pOut += n2;
+          }
+          a1 += n1;
+          a2 += n2;
+        }
+        pNew->nRecord = pOut - pNew->aRecord;
+      }
+      sqlite3_free(pExist);
+    }
+  }else{
+    int op1 = pExist->op;
+
+    /*
+    **   op1=INSERT, op2=INSERT      ->      Unsupported. Discard op2.
+    **   op1=INSERT, op2=UPDATE      ->      INSERT.
+    **   op1=INSERT, op2=DELETE      ->      (none)
+    **
+    **   op1=UPDATE, op2=INSERT      ->      Unsupported. Discard op2.
+    **   op1=UPDATE, op2=UPDATE      ->      UPDATE.
+    **   op1=UPDATE, op2=DELETE      ->      DELETE.
+    **
+    **   op1=DELETE, op2=INSERT      ->      UPDATE.
+    **   op1=DELETE, op2=UPDATE      ->      Unsupported. Discard op2.
+    **   op1=DELETE, op2=DELETE      ->      Unsupported. Discard op2.
+    */
+    if( (op1==SQLITE_INSERT && op2==SQLITE_INSERT)
+     || (op1==SQLITE_UPDATE && op2==SQLITE_INSERT)
+     || (op1==SQLITE_DELETE && op2==SQLITE_UPDATE)
+     || (op1==SQLITE_DELETE && op2==SQLITE_DELETE)
+    ){
+      pNew = pExist;
+    }else if( op1==SQLITE_INSERT && op2==SQLITE_DELETE ){
+      sqlite3_free(pExist);
+      assert( pNew==0 );
+    }else{
+      u8 *aExist = pExist->aRecord;
+      sqlite3_int64 nByte;
+      u8 *aCsr;
+
+      /* Allocate a new SessionChange object. Ensure that the aRecord[]
+      ** buffer of the new object is large enough to hold any record that
+      ** may be generated by combining the input records.  */
+      nByte = sizeof(SessionChange) + pExist->nRecord + nRec;
+      pNew = (SessionChange *)sqlite3_malloc64(nByte);
+      if( !pNew ){
+        sqlite3_free(pExist);
+        return SQLITE_NOMEM;
+      }
+      memset(pNew, 0, sizeof(SessionChange));
+      pNew->bIndirect = (bIndirect && pExist->bIndirect);
+      aCsr = pNew->aRecord = (u8 *)&pNew[1];
+
+      if( op1==SQLITE_INSERT ){             /* INSERT + UPDATE */
+        u8 *a1 = aRec;
+        assert( op2==SQLITE_UPDATE );
+        pNew->op = SQLITE_INSERT;
+        if( bPatchset==0 ) sessionSkipRecord(&a1, pTab->nCol);
+        sessionMergeRecord(&aCsr, pTab->nCol, aExist, a1);
+      }else if( op1==SQLITE_DELETE ){       /* DELETE + INSERT */
+        assert( op2==SQLITE_INSERT );
+        pNew->op = SQLITE_UPDATE;
+        if( bPatchset ){
+          memcpy(aCsr, aRec, nRec);
+          aCsr += nRec;
+        }else{
+          if( 0==sessionMergeUpdate(&aCsr, pTab, bPatchset, aExist, 0,aRec,0) ){
+            sqlite3_free(pNew);
+            pNew = 0;
+          }
+        }
+      }else if( op2==SQLITE_UPDATE ){       /* UPDATE + UPDATE */
+        u8 *a1 = aExist;
+        u8 *a2 = aRec;
+        assert( op1==SQLITE_UPDATE );
+        if( bPatchset==0 ){
+          sessionSkipRecord(&a1, pTab->nCol);
+          sessionSkipRecord(&a2, pTab->nCol);
+        }
+        pNew->op = SQLITE_UPDATE;
+        if( 0==sessionMergeUpdate(&aCsr, pTab, bPatchset, aRec, aExist,a1,a2) ){
+          sqlite3_free(pNew);
+          pNew = 0;
+        }
+      }else{                                /* UPDATE + DELETE */
+        assert( op1==SQLITE_UPDATE && op2==SQLITE_DELETE );
+        pNew->op = SQLITE_DELETE;
+        if( bPatchset ){
+          memcpy(aCsr, aRec, nRec);
+          aCsr += nRec;
+        }else{
+          sessionMergeRecord(&aCsr, pTab->nCol, aRec, aExist);
+        }
+      }
+
+      if( pNew ){
+        pNew->nRecord = (int)(aCsr - pNew->aRecord);
+      }
+      sqlite3_free(pExist);
+    }
+  }
+
+  *ppNew = pNew;
+  return rc;
+}
+
+/*
+** Check if a changeset entry with nCol columns and the PK array passed
+** as the final argument to this function is compatible with SessionTable
+** pTab. If so, return 1. Otherwise, if they are incompatible in some way,
+** return 0.
+*/
+static int sessionChangesetCheckCompat(
+  SessionTable *pTab,
+  int nCol,
+  u8 *abPK
+){
+  if( pTab->azCol && nCol<pTab->nCol ){
+    int ii;
+    for(ii=0; ii<pTab->nCol; ii++){
+      u8 bPK = (ii < nCol) ? abPK[ii] : 0;
+      if( pTab->abPK[ii]!=bPK ) return 0;
+    }
+    return 1;
+  }
+  return (pTab->nCol==nCol && 0==memcmp(abPK, pTab->abPK, nCol));
+}
+
+static int sessionChangesetExtendRecord(
+  sqlite3_changegroup *pGrp,
+  SessionTable *pTab,
+  int nCol,
+  int op,
+  const u8 *aRec,
+  int nRec,
+  SessionBuffer *pOut
+){
+  int rc = SQLITE_OK;
+  int ii = 0;
+
+  assert( pTab->azCol );
+  assert( nCol<pTab->nCol );
+
+  pOut->nBuf = 0;
+  if( op==SQLITE_INSERT || (op==SQLITE_DELETE && pGrp->bPatch==0) ){
+    /* Append the missing default column values to the record. */
+    sessionAppendBlob(pOut, aRec, nRec, &rc);
+    if( rc==SQLITE_OK && pTab->pDfltStmt==0 ){
+      rc = sessionPrepareDfltStmt(pGrp->db, pTab, &pTab->pDfltStmt);
+      if( rc==SQLITE_OK && SQLITE_ROW!=sqlite3_step(pTab->pDfltStmt) ){
+        rc = sqlite3_errcode(pGrp->db);
+      }
+    }
+    for(ii=nCol; rc==SQLITE_OK && ii<pTab->nCol; ii++){
+      int eType = sqlite3_column_type(pTab->pDfltStmt, ii);
+      sessionAppendByte(pOut, eType, &rc);
+      switch( eType ){
+        case SQLITE_FLOAT:
+        case SQLITE_INTEGER: {
+          i64 iVal;
+          if( eType==SQLITE_INTEGER ){
+            iVal = sqlite3_column_int64(pTab->pDfltStmt, ii);
+          }else{
+            double rVal = sqlite3_column_int64(pTab->pDfltStmt, ii);
+            memcpy(&iVal, &rVal, sizeof(i64));
+          }
+          if( SQLITE_OK==sessionBufferGrow(pOut, 8, &rc) ){
+            sessionPutI64(&pOut->aBuf[pOut->nBuf], iVal);
+            pOut->nBuf += 8;
+          }
+          break;
+        }
+
+        case SQLITE_BLOB:
+        case SQLITE_TEXT: {
+          int n = sqlite3_column_bytes(pTab->pDfltStmt, ii);
+          sessionAppendVarint(pOut, n, &rc);
+          if( eType==SQLITE_TEXT ){
+            const u8 *z = (const u8*)sqlite3_column_text(pTab->pDfltStmt, ii);
+            sessionAppendBlob(pOut, z, n, &rc);
+          }else{
+            const u8 *z = (const u8*)sqlite3_column_blob(pTab->pDfltStmt, ii);
+            sessionAppendBlob(pOut, z, n, &rc);
+          }
+          break;
+        }
+
+        default:
+          assert( eType==SQLITE_NULL );
+          break;
+      }
+    }
+  }else if( op==SQLITE_UPDATE ){
+    /* Append missing "undefined" entries to the old.* record. And, if this
+    ** is an UPDATE, to the new.* record as well.  */
+    int iOff = 0;
+    if( pGrp->bPatch==0 ){
+      for(ii=0; ii<nCol; ii++){
+        iOff += sessionSerialLen(&aRec[iOff]);
+      }
+      sessionAppendBlob(pOut, aRec, iOff, &rc);
+      for(ii=0; ii<(pTab->nCol-nCol); ii++){
+        sessionAppendByte(pOut, 0x00, &rc);
+      }
+    }
+
+    sessionAppendBlob(pOut, &aRec[iOff], nRec-iOff, &rc);
+    for(ii=0; ii<(pTab->nCol-nCol); ii++){
+      sessionAppendByte(pOut, 0x00, &rc);
+    }
+  }else{
+    assert( op==SQLITE_DELETE && pGrp->bPatch );
+    sessionAppendBlob(pOut, aRec, nRec, &rc);
+  }
+
+  return rc;
+}
+
+/*
+** Locate or create a SessionTable object that may be used to add the
+** change currently pointed to by iterator pIter to changegroup pGrp.
+** If successful, set output variable (*ppTab) to point to the table
+** object and return SQLITE_OK. Otherwise, if some error occurs, return
+** an SQLite error code and leave (*ppTab) set to NULL.
+*/
+static int sessionChangesetFindTable(
+  sqlite3_changegroup *pGrp,
+  const char *zTab,
+  sqlite3_changeset_iter *pIter,
+  SessionTable **ppTab
+){
+  int rc = SQLITE_OK;
+  SessionTable *pTab = 0;
+  int nTab = (int)strlen(zTab);
+  u8 *abPK = 0;
+  int nCol = 0;
+
+  *ppTab = 0;
+  sqlite3changeset_pk(pIter, &abPK, &nCol);
+
+  /* Search the list for an existing table */
+  for(pTab = pGrp->pList; pTab; pTab=pTab->pNext){
+    if( 0==sqlite3_strnicmp(pTab->zName, zTab, nTab+1) ) break;
+  }
+
+  /* If one was not found above, create a new table now */
+  if( !pTab ){
+    SessionTable **ppNew;
+
+    pTab = sqlite3_malloc64(sizeof(SessionTable) + nCol + nTab+1);
+    if( !pTab ){
+      return SQLITE_NOMEM;
+    }
+    memset(pTab, 0, sizeof(SessionTable));
+    pTab->nCol = nCol;
+    pTab->abPK = (u8*)&pTab[1];
+    memcpy(pTab->abPK, abPK, nCol);
+    pTab->zName = (char*)&pTab->abPK[nCol];
+    memcpy(pTab->zName, zTab, nTab+1);
+
+    if( pGrp->db ){
+      pTab->nCol = 0;
+      rc = sessionInitTable(0, pTab, pGrp->db, pGrp->zDb);
+      if( rc ){
+        assert( pTab->azCol==0 );
+        sqlite3_free(pTab);
+        return rc;
+      }
+    }
+
+    /* The new object must be linked on to the end of the list, not
+    ** simply added to the start of it. This is to ensure that the
+    ** tables within the output of sqlite3changegroup_output() are in
+    ** the right order.  */
+    for(ppNew=&pGrp->pList; *ppNew; ppNew=&(*ppNew)->pNext);
+    *ppNew = pTab;
+  }
+
+  /* Check that the table is compatible. */
+  if( !sessionChangesetCheckCompat(pTab, nCol, abPK) ){
+    rc = SQLITE_SCHEMA;
+  }
+
+  *ppTab = pTab;
+  return rc;
+}
+
+/*
+** Add the change currently indicated by iterator pIter to the hash table
+** belonging to changegroup pGrp.
+*/
+static int sessionOneChangeToHash(
+  sqlite3_changegroup *pGrp,
+  sqlite3_changeset_iter *pIter,
+  int bRebase
+){
+  int rc = SQLITE_OK;
+  int nCol = 0;
+  int op = 0;
+  int iHash = 0;
+  int bIndirect = 0;
+  SessionChange *pChange = 0;
+  SessionChange *pExist = 0;
+  SessionChange **pp = 0;
+  SessionTable *pTab = 0;
+  u8 *aRec = &pIter->in.aData[pIter->in.iCurrent + 2];
+  int nRec = (pIter->in.iNext - pIter->in.iCurrent) - 2;
+
+  assert( nRec>0 );
+
+  /* Ensure that only changesets, or only patchsets, but not a mixture
+  ** of both, are being combined. It is an error to try to combine a
+  ** changeset and a patchset.  */
+  if( pGrp->pList==0 ){
+    pGrp->bPatch = pIter->bPatchset;
+  }else if( pIter->bPatchset!=pGrp->bPatch ){
+    rc = SQLITE_ERROR;
+  }
+
+  if( rc==SQLITE_OK ){
+    const char *zTab = 0;
+    sqlite3changeset_op(pIter, &zTab, &nCol, &op, &bIndirect);
+    rc = sessionChangesetFindTable(pGrp, zTab, pIter, &pTab);
+  }
+
+  if( rc==SQLITE_OK && nCol<pTab->nCol ){
+    SessionBuffer *pBuf = &pGrp->rec;
+    rc = sessionChangesetExtendRecord(pGrp, pTab, nCol, op, aRec, nRec, pBuf);
+    aRec = pBuf->aBuf;
+    nRec = pBuf->nBuf;
+    assert( pGrp->db );
+  }
+
+  if( rc==SQLITE_OK && sessionGrowHash(0, pIter->bPatchset, pTab) ){
+    rc = SQLITE_NOMEM;
+  }
+
+  if( rc==SQLITE_OK ){
+    /* Search for existing entry. If found, remove it from the hash table.
+    ** Code below may link it back in.  */
+    iHash = sessionChangeHash(
+        pTab, (pIter->bPatchset && op==SQLITE_DELETE), aRec, pTab->nChange
+    );
+    for(pp=&pTab->apChange[iHash]; *pp; pp=&(*pp)->pNext){
+      int bPkOnly1 = 0;
+      int bPkOnly2 = 0;
+      if( pIter->bPatchset ){
+        bPkOnly1 = (*pp)->op==SQLITE_DELETE;
+        bPkOnly2 = op==SQLITE_DELETE;
+      }
+      if( sessionChangeEqual(pTab, bPkOnly1, (*pp)->aRecord, bPkOnly2, aRec) ){
+        pExist = *pp;
+        *pp = (*pp)->pNext;
+        pTab->nEntry--;
+        break;
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sessionChangeMerge(pTab, bRebase,
+        pIter->bPatchset, pExist, op, bIndirect, aRec, nRec, &pChange
+    );
+  }
+  if( rc==SQLITE_OK && pChange ){
+    pChange->pNext = pTab->apChange[iHash];
+    pTab->apChange[iHash] = pChange;
+    pTab->nEntry++;
+  }
+
+  if( rc==SQLITE_OK ) rc = pIter->rc;
+  return rc;
+}
+
+/*
+** Add all changes in the changeset traversed by the iterator passed as
+** the first argument to the changegroup hash tables.
+*/
+static int sessionChangesetToHash(
+  sqlite3_changeset_iter *pIter,   /* Iterator to read from */
+  sqlite3_changegroup *pGrp,       /* Changegroup object to add changeset to */
+  int bRebase                      /* True if hash table is for rebasing */
+){
+  u8 *aRec;
+  int nRec;
+  int rc = SQLITE_OK;
+
+  pIter->in.bNoDiscard = 1;
+  while( SQLITE_ROW==(sessionChangesetNext(pIter, &aRec, &nRec, 0)) ){
+    rc = sessionOneChangeToHash(pGrp, pIter, bRebase);
+    if( rc!=SQLITE_OK ) break;
+  }
+
+  if( rc==SQLITE_OK ) rc = pIter->rc;
+  return rc;
+}
+
+/*
+** Serialize a changeset (or patchset) based on all changesets (or patchsets)
+** added to the changegroup object passed as the first argument.
+**
+** If xOutput is not NULL, then the changeset/patchset is returned to the
+** user via one or more calls to xOutput, as with the other streaming
+** interfaces.
+**
+** Or, if xOutput is NULL, then (*ppOut) is populated with a pointer to a
+** buffer containing the output changeset before this function returns. In
+** this case (*pnOut) is set to the size of the output buffer in bytes. It
+** is the responsibility of the caller to free the output buffer using
+** sqlite3_free() when it is no longer required.
+**
+** If successful, SQLITE_OK is returned. Or, if an error occurs, an SQLite
+** error code. If an error occurs and xOutput is NULL, (*ppOut) and (*pnOut)
+** are both set to 0 before returning.
+*/
+static int sessionChangegroupOutput(
+  sqlite3_changegroup *pGrp,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut,
+  int *pnOut,
+  void **ppOut
+){
+  int rc = SQLITE_OK;
+  SessionBuffer buf = {0, 0, 0};
+  SessionTable *pTab;
+  assert( xOutput==0 || (ppOut==0 && pnOut==0) );
+
+  /* Create the serialized output changeset based on the contents of the
+  ** hash tables attached to the SessionTable objects in list p->pList.
+  */
+  for(pTab=pGrp->pList; rc==SQLITE_OK && pTab; pTab=pTab->pNext){
+    int i;
+    if( pTab->nEntry==0 ) continue;
+
+    sessionAppendTableHdr(&buf, pGrp->bPatch, pTab, &rc);
+    for(i=0; i<pTab->nChange; i++){
+      SessionChange *p;
+      for(p=pTab->apChange[i]; p; p=p->pNext){
+        sessionAppendByte(&buf, p->op, &rc);
+        sessionAppendByte(&buf, p->bIndirect, &rc);
+        sessionAppendBlob(&buf, p->aRecord, p->nRecord, &rc);
+        if( rc==SQLITE_OK && xOutput && buf.nBuf>=sessions_strm_chunk_size ){
+          rc = xOutput(pOut, buf.aBuf, buf.nBuf);
+          buf.nBuf = 0;
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( xOutput ){
+      if( buf.nBuf>0 ) rc = xOutput(pOut, buf.aBuf, buf.nBuf);
+    }else if( ppOut ){
+      *ppOut = buf.aBuf;
+      if( pnOut ) *pnOut = buf.nBuf;
+      buf.aBuf = 0;
+    }
+  }
+  sqlite3_free(buf.aBuf);
+
+  return rc;
+}
+
+/*
+** Allocate a new, empty, sqlite3_changegroup.
+*/
+SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp){
+  int rc = SQLITE_OK;             /* Return code */
+  sqlite3_changegroup *p;         /* New object */
+  p = (sqlite3_changegroup*)sqlite3_malloc(sizeof(sqlite3_changegroup));
+  if( p==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    memset(p, 0, sizeof(sqlite3_changegroup));
+  }
+  *pp = p;
+  return rc;
+}
+
+/*
+** Provide a database schema to the changegroup object.
+*/
+SQLITE_API int sqlite3changegroup_schema(
+  sqlite3_changegroup *pGrp,
+  sqlite3 *db,
+  const char *zDb
+){
+  int rc = SQLITE_OK;
+
+  if( pGrp->pList || pGrp->db ){
+    /* Cannot add a schema after one or more calls to sqlite3changegroup_add(),
+    ** or after sqlite3changegroup_schema() has already been called. */
+    rc = SQLITE_MISUSE;
+  }else{
+    pGrp->zDb = sqlite3_mprintf("%s", zDb);
+    if( pGrp->zDb==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pGrp->db = db;
+    }
+  }
+  return rc;
+}
+
+/*
+** Add the changeset currently stored in buffer pData, size nData bytes,
+** to changeset-group p.
+*/
+SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup *pGrp, int nData, void *pData){
+  sqlite3_changeset_iter *pIter;  /* Iterator opened on pData/nData */
+  int rc;                         /* Return code */
+
+  rc = sqlite3changeset_start(&pIter, nData, pData);
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetToHash(pIter, pGrp, 0);
+  }
+  sqlite3changeset_finalize(pIter);
+  return rc;
+}
+
+/*
+** Add a single change to a changeset-group.
+*/
+SQLITE_API int sqlite3changegroup_add_change(
+  sqlite3_changegroup *pGrp,
+  sqlite3_changeset_iter *pIter
+){
+  if( pIter->in.iCurrent==pIter->in.iNext
+   || pIter->rc!=SQLITE_OK
+   || pIter->bInvert
+  ){
+    /* Iterator does not point to any valid entry or is an INVERT iterator. */
+    return SQLITE_ERROR;
+  }
+  return sessionOneChangeToHash(pGrp, pIter, 0);
+}
+
+/*
+** Obtain a buffer containing a changeset representing the concatenation
+** of all changesets added to the group so far.
+*/
+SQLITE_API int sqlite3changegroup_output(
+    sqlite3_changegroup *pGrp,
+    int *pnData,
+    void **ppData
+){
+  return sessionChangegroupOutput(pGrp, 0, 0, pnData, ppData);
+}
+
+/*
+** Streaming versions of changegroup_add().
+*/
+SQLITE_API int sqlite3changegroup_add_strm(
+  sqlite3_changegroup *pGrp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn
+){
+  sqlite3_changeset_iter *pIter;  /* Iterator opened on pData/nData */
+  int rc;                         /* Return code */
+
+  rc = sqlite3changeset_start_strm(&pIter, xInput, pIn);
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetToHash(pIter, pGrp, 0);
+  }
+  sqlite3changeset_finalize(pIter);
+  return rc;
+}
+
+/*
+** Streaming versions of changegroup_output().
+*/
+SQLITE_API int sqlite3changegroup_output_strm(
+  sqlite3_changegroup *pGrp,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  return sessionChangegroupOutput(pGrp, xOutput, pOut, 0, 0);
+}
+
+/*
+** Delete a changegroup object.
+*/
+SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup *pGrp){
+  if( pGrp ){
+    sqlite3_free(pGrp->zDb);
+    sessionDeleteTable(0, pGrp->pList);
+    sqlite3_free(pGrp->rec.aBuf);
+    sqlite3_free(pGrp);
+  }
+}
+
+/*
+** Combine two changesets together.
+*/
+SQLITE_API int sqlite3changeset_concat(
+  int nLeft,                      /* Number of bytes in lhs input */
+  void *pLeft,                    /* Lhs input changeset */
+  int nRight                      /* Number of bytes in rhs input */,
+  void *pRight,                   /* Rhs input changeset */
+  int *pnOut,                     /* OUT: Number of bytes in output changeset */
+  void **ppOut                    /* OUT: changeset (left <concat> right) */
+){
+  sqlite3_changegroup *pGrp;
+  int rc;
+
+  rc = sqlite3changegroup_new(&pGrp);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_add(pGrp, nLeft, pLeft);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_add(pGrp, nRight, pRight);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
+  }
+  sqlite3changegroup_delete(pGrp);
+
+  return rc;
+}
+
+/*
+** Streaming version of sqlite3changeset_concat().
+*/
+SQLITE_API int sqlite3changeset_concat_strm(
+  int (*xInputA)(void *pIn, void *pData, int *pnData),
+  void *pInA,
+  int (*xInputB)(void *pIn, void *pData, int *pnData),
+  void *pInB,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  sqlite3_changegroup *pGrp;
+  int rc;
+
+  rc = sqlite3changegroup_new(&pGrp);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_add_strm(pGrp, xInputA, pInA);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_add_strm(pGrp, xInputB, pInB);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3changegroup_output_strm(pGrp, xOutput, pOut);
+  }
+  sqlite3changegroup_delete(pGrp);
+
+  return rc;
+}
+
+/*
+** Changeset rebaser handle.
+*/
+struct sqlite3_rebaser {
+  sqlite3_changegroup grp;        /* Hash table */
+};
+
+/*
+** Buffers a1 and a2 must both contain a sessions module record nCol
+** fields in size. This function appends an nCol sessions module
+** record to buffer pBuf that is a copy of a1, except that for
+** each field that is undefined in a1[], swap in the field from a2[].
+*/
+static void sessionAppendRecordMerge(
+  SessionBuffer *pBuf,            /* Buffer to append to */
+  int nCol,                       /* Number of columns in each record */
+  u8 *a1, int n1,                 /* Record 1 */
+  u8 *a2, int n2,                 /* Record 2 */
+  int *pRc                        /* IN/OUT: error code */
+){
+  sessionBufferGrow(pBuf, n1+n2, pRc);
+  if( *pRc==SQLITE_OK ){
+    int i;
+    u8 *pOut = &pBuf->aBuf[pBuf->nBuf];
+    for(i=0; i<nCol; i++){
+      int nn1 = sessionSerialLen(a1);
+      int nn2 = sessionSerialLen(a2);
+      if( *a1==0 || *a1==0xFF ){
+        memcpy(pOut, a2, nn2);
+        pOut += nn2;
+      }else{
+        memcpy(pOut, a1, nn1);
+        pOut += nn1;
+      }
+      a1 += nn1;
+      a2 += nn2;
+    }
+
+    pBuf->nBuf = pOut-pBuf->aBuf;
+    assert( pBuf->nBuf<=pBuf->nAlloc );
+  }
+}
+
+/*
+** This function is called when rebasing a local UPDATE change against one
+** or more remote UPDATE changes. The aRec/nRec buffer contains the current
+** old.* and new.* records for the change. The rebase buffer (a single
+** record) is in aChange/nChange. The rebased change is appended to buffer
+** pBuf.
+**
+** Rebasing the UPDATE involves:
+**
+**   * Removing any changes to fields for which the corresponding field
+**     in the rebase buffer is set to "replaced" (type 0xFF). If this
+**     means the UPDATE change updates no fields, nothing is appended
+**     to the output buffer.
+**
+**   * For each field modified by the local change for which the
+**     corresponding field in the rebase buffer is not "undefined" (0x00)
+**     or "replaced" (0xFF), the old.* value is replaced by the value
+**     in the rebase buffer.
+*/
+static void sessionAppendPartialUpdate(
+  SessionBuffer *pBuf,            /* Append record here */
+  sqlite3_changeset_iter *pIter,  /* Iterator pointed at local change */
+  u8 *aRec, int nRec,             /* Local change */
+  u8 *aChange, int nChange,       /* Record to rebase against */
+  int *pRc                        /* IN/OUT: Return Code */
+){
+  sessionBufferGrow(pBuf, 2+nRec+nChange, pRc);
+  if( *pRc==SQLITE_OK ){
+    int bData = 0;
+    u8 *pOut = &pBuf->aBuf[pBuf->nBuf];
+    int i;
+    u8 *a1 = aRec;
+    u8 *a2 = aChange;
+
+    *pOut++ = SQLITE_UPDATE;
+    *pOut++ = pIter->bIndirect;
+    for(i=0; i<pIter->nCol; i++){
+      int n1 = sessionSerialLen(a1);
+      int n2 = sessionSerialLen(a2);
+      if( pIter->abPK[i] || a2[0]==0 ){
+        if( !pIter->abPK[i] && a1[0] ) bData = 1;
+        memcpy(pOut, a1, n1);
+        pOut += n1;
+      }else if( a2[0]!=0xFF && a1[0] ){
+        bData = 1;
+        memcpy(pOut, a2, n2);
+        pOut += n2;
+      }else{
+        *pOut++ = '\0';
+      }
+      a1 += n1;
+      a2 += n2;
+    }
+    if( bData ){
+      a2 = aChange;
+      for(i=0; i<pIter->nCol; i++){
+        int n1 = sessionSerialLen(a1);
+        int n2 = sessionSerialLen(a2);
+        if( pIter->abPK[i] || a2[0]!=0xFF ){
+          memcpy(pOut, a1, n1);
+          pOut += n1;
+        }else{
+          *pOut++ = '\0';
+        }
+        a1 += n1;
+        a2 += n2;
+      }
+      pBuf->nBuf = (pOut - pBuf->aBuf);
+    }
+  }
+}
+
+/*
+** pIter is configured to iterate through a changeset. This function rebases
+** that changeset according to the current configuration of the rebaser
+** object passed as the first argument. If no error occurs and argument xOutput
+** is not NULL, then the changeset is returned to the caller by invoking
+** xOutput zero or more times and SQLITE_OK returned. Or, if xOutput is NULL,
+** then (*ppOut) is set to point to a buffer containing the rebased changeset
+** before this function returns. In this case (*pnOut) is set to the size of
+** the buffer in bytes.  It is the responsibility of the caller to eventually
+** free the (*ppOut) buffer using sqlite3_free().
+**
+** If an error occurs, an SQLite error code is returned. If ppOut and
+** pnOut are not NULL, then the two output parameters are set to 0 before
+** returning.
+*/
+static int sessionRebase(
+  sqlite3_rebaser *p,             /* Rebaser hash table */
+  sqlite3_changeset_iter *pIter,  /* Input data */
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut,                     /* Context for xOutput callback */
+  int *pnOut,                     /* OUT: Number of bytes in output changeset */
+  void **ppOut                    /* OUT: Inverse of pChangeset */
+){
+  int rc = SQLITE_OK;
+  u8 *aRec = 0;
+  int nRec = 0;
+  int bNew = 0;
+  SessionTable *pTab = 0;
+  SessionBuffer sOut = {0,0,0};
+
+  while( SQLITE_ROW==sessionChangesetNext(pIter, &aRec, &nRec, &bNew) ){
+    SessionChange *pChange = 0;
+    int bDone = 0;
+
+    if( bNew ){
+      const char *zTab = pIter->zTab;
+      for(pTab=p->grp.pList; pTab; pTab=pTab->pNext){
+        if( 0==sqlite3_stricmp(pTab->zName, zTab) ) break;
+      }
+      bNew = 0;
+
+      /* A patchset may not be rebased */
+      if( pIter->bPatchset ){
+        rc = SQLITE_ERROR;
+      }
+
+      /* Append a table header to the output for this new table */
+      sessionAppendByte(&sOut, pIter->bPatchset ? 'P' : 'T', &rc);
+      sessionAppendVarint(&sOut, pIter->nCol, &rc);
+      sessionAppendBlob(&sOut, pIter->abPK, pIter->nCol, &rc);
+      sessionAppendBlob(&sOut,(u8*)pIter->zTab,(int)strlen(pIter->zTab)+1,&rc);
+    }
+
+    if( pTab && rc==SQLITE_OK ){
+      int iHash = sessionChangeHash(pTab, 0, aRec, pTab->nChange);
+
+      for(pChange=pTab->apChange[iHash]; pChange; pChange=pChange->pNext){
+        if( sessionChangeEqual(pTab, 0, aRec, 0, pChange->aRecord) ){
+          break;
+        }
+      }
+    }
+
+    if( pChange ){
+      assert( pChange->op==SQLITE_DELETE || pChange->op==SQLITE_INSERT );
+      switch( pIter->op ){
+        case SQLITE_INSERT:
+          if( pChange->op==SQLITE_INSERT ){
+            bDone = 1;
+            if( pChange->bIndirect==0 ){
+              sessionAppendByte(&sOut, SQLITE_UPDATE, &rc);
+              sessionAppendByte(&sOut, pIter->bIndirect, &rc);
+              sessionAppendBlob(&sOut, pChange->aRecord, pChange->nRecord, &rc);
+              sessionAppendBlob(&sOut, aRec, nRec, &rc);
+            }
+          }
+          break;
+
+        case SQLITE_UPDATE:
+          bDone = 1;
+          if( pChange->op==SQLITE_DELETE ){
+            if( pChange->bIndirect==0 ){
+              u8 *pCsr = aRec;
+              sessionSkipRecord(&pCsr, pIter->nCol);
+              sessionAppendByte(&sOut, SQLITE_INSERT, &rc);
+              sessionAppendByte(&sOut, pIter->bIndirect, &rc);
+              sessionAppendRecordMerge(&sOut, pIter->nCol,
+                  pCsr, nRec-(pCsr-aRec),
+                  pChange->aRecord, pChange->nRecord, &rc
+              );
+            }
+          }else{
+            sessionAppendPartialUpdate(&sOut, pIter,
+                aRec, nRec, pChange->aRecord, pChange->nRecord, &rc
+            );
+          }
+          break;
+
+        default:
+          assert( pIter->op==SQLITE_DELETE );
+          bDone = 1;
+          if( pChange->op==SQLITE_INSERT ){
+            sessionAppendByte(&sOut, SQLITE_DELETE, &rc);
+            sessionAppendByte(&sOut, pIter->bIndirect, &rc);
+            sessionAppendRecordMerge(&sOut, pIter->nCol,
+                pChange->aRecord, pChange->nRecord, aRec, nRec, &rc
+            );
+          }
+          break;
+      }
+    }
+
+    if( bDone==0 ){
+      sessionAppendByte(&sOut, pIter->op, &rc);
+      sessionAppendByte(&sOut, pIter->bIndirect, &rc);
+      sessionAppendBlob(&sOut, aRec, nRec, &rc);
+    }
+    if( rc==SQLITE_OK && xOutput && sOut.nBuf>sessions_strm_chunk_size ){
+      rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
+      sOut.nBuf = 0;
+    }
+    if( rc ) break;
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(sOut.aBuf);
+    memset(&sOut, 0, sizeof(sOut));
+  }
+
+  if( rc==SQLITE_OK ){
+    if( xOutput ){
+      if( sOut.nBuf>0 ){
+        rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
+      }
+    }else if( ppOut ){
+      *ppOut = (void*)sOut.aBuf;
+      *pnOut = sOut.nBuf;
+      sOut.aBuf = 0;
+    }
+  }
+  sqlite3_free(sOut.aBuf);
+  return rc;
+}
+
+/*
+** Create a new rebaser object.
+*/
+SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew){
+  int rc = SQLITE_OK;
+  sqlite3_rebaser *pNew;
+
+  pNew = sqlite3_malloc(sizeof(sqlite3_rebaser));
+  if( pNew==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    memset(pNew, 0, sizeof(sqlite3_rebaser));
+  }
+  *ppNew = pNew;
+  return rc;
+}
+
+/*
+** Call this one or more times to configure a rebaser.
+*/
+SQLITE_API int sqlite3rebaser_configure(
+  sqlite3_rebaser *p,
+  int nRebase, const void *pRebase
+){
+  sqlite3_changeset_iter *pIter = 0;   /* Iterator opened on pData/nData */
+  int rc;                              /* Return code */
+  rc = sqlite3changeset_start(&pIter, nRebase, (void*)pRebase);
+  if( rc==SQLITE_OK ){
+    rc = sessionChangesetToHash(pIter, &p->grp, 1);
+  }
+  sqlite3changeset_finalize(pIter);
+  return rc;
+}
+
+/*
+** Rebase a changeset according to current rebaser configuration
+*/
+SQLITE_API int sqlite3rebaser_rebase(
+  sqlite3_rebaser *p,
+  int nIn, const void *pIn,
+  int *pnOut, void **ppOut
+){
+  sqlite3_changeset_iter *pIter = 0;   /* Iterator to skip through input */
+  int rc = sqlite3changeset_start(&pIter, nIn, (void*)pIn);
+
+  if( rc==SQLITE_OK ){
+    rc = sessionRebase(p, pIter, 0, 0, pnOut, ppOut);
+    sqlite3changeset_finalize(pIter);
+  }
+
+  return rc;
+}
+
+/*
+** Rebase a changeset according to current rebaser configuration
+*/
+SQLITE_API int sqlite3rebaser_rebase_strm(
+  sqlite3_rebaser *p,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+){
+  sqlite3_changeset_iter *pIter = 0;   /* Iterator to skip through input */
+  int rc = sqlite3changeset_start_strm(&pIter, xInput, pIn);
+
+  if( rc==SQLITE_OK ){
+    rc = sessionRebase(p, pIter, xOutput, pOut, 0, 0);
+    sqlite3changeset_finalize(pIter);
+  }
+
+  return rc;
+}
+
+/*
+** Destroy a rebaser object
+*/
+SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p){
+  if( p ){
+    sessionDeleteTable(0, p->grp.pList);
+    sqlite3_free(p->grp.rec.aBuf);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Global configuration
+*/
+SQLITE_API int sqlite3session_config(int op, void *pArg){
+  int rc = SQLITE_OK;
+  switch( op ){
+    case SQLITE_SESSION_CONFIG_STRMSIZE: {
+      int *pInt = (int*)pArg;
+      if( *pInt>0 ){
+        sessions_strm_chunk_size = *pInt;
+      }
+      *pInt = sessions_strm_chunk_size;
+      break;
+    }
+    default:
+      rc = SQLITE_MISUSE;
+      break;
+  }
+  return rc;
+}
+
+#endif /* SQLITE_ENABLE_SESSION && SQLITE_ENABLE_PREUPDATE_HOOK */
+
+/************** End of sqlite3session.c **************************************/
+/************** Begin file fts5.c ********************************************/
+
+/*
+** This, the "fts5.c" source file, is a composite file that is itself
+** assembled from the following files:
+**
+**    fts5.h
+**    fts5Int.h
+**    fts5parse.h          <--- Generated from fts5parse.y by Lemon
+**    fts5parse.c          <--- Generated from fts5parse.y by Lemon
+**    fts5_aux.c
+**    fts5_buffer.c
+**    fts5_config.c
+**    fts5_expr.c
+**    fts5_hash.c
+**    fts5_index.c
+**    fts5_main.c
+**    fts5_storage.c
+**    fts5_tokenize.c
+**    fts5_unicode2.c
+**    fts5_varint.c
+**    fts5_vocab.c
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS5)
+
+#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
+# define NDEBUG 1
+#endif
+#if defined(NDEBUG) && defined(SQLITE_DEBUG)
+# undef NDEBUG
+#endif
+
+#ifdef HAVE_STDINT_H
+/* #include <stdint.h> */
+#endif
+#ifdef HAVE_INTTYPES_H
+/* #include <inttypes.h> */
+#endif
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Interfaces to extend FTS5. Using the interfaces defined in this file,
+** FTS5 may be extended with:
+**
+**     * custom tokenizers, and
+**     * custom auxiliary functions.
+*/
+
+
+#ifndef _FTS5_H
+#define _FTS5_H
+
+/* #include "sqlite3.h" */
+
+#if 0
+extern "C" {
+#endif
+
+/*************************************************************************
+** CUSTOM AUXILIARY FUNCTIONS
+**
+** Virtual table implementations may overload SQL functions by implementing
+** the sqlite3_module.xFindFunction() method.
+*/
+
+typedef struct Fts5ExtensionApi Fts5ExtensionApi;
+typedef struct Fts5Context Fts5Context;
+typedef struct Fts5PhraseIter Fts5PhraseIter;
+
+typedef void (*fts5_extension_function)(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+);
+
+struct Fts5PhraseIter {
+  const unsigned char *a;
+  const unsigned char *b;
+};
+
+/*
+** EXTENSION API FUNCTIONS
+**
+** xUserData(pFts):
+**   Return a copy of the pUserData pointer passed to the xCreateFunction()
+**   API when the extension function was registered.
+**
+** xColumnTotalSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the FTS5 table. Or, if iCol is
+**   non-negative but less than the number of columns in the table, return
+**   the total number of tokens in column iCol, considering all rows in
+**   the FTS5 table.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+** xColumnCount(pFts):
+**   Return the number of columns in the table.
+**
+** xColumnSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the current row. Or, if iCol is
+**   non-negative but less than the number of columns in the table, set
+**   *pnToken to the number of tokens in column iCol of the current row.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+**   This function may be quite inefficient if used with an FTS5 table
+**   created with the "columnsize=0" option.
+**
+** xColumnText:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the text of column iCol of
+**   the current document. If successful, (*pz) is set to point to a buffer
+**   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
+**   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
+**   if an error occurs, an SQLite error code is returned and the final values
+**   of (*pz) and (*pn) are undefined.
+**
+** xPhraseCount:
+**   Returns the number of phrases in the current query expression.
+**
+** xPhraseSize:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of phrases in the current query, as returned by xPhraseCount,
+**   0 is returned. Otherwise, this function returns the number of tokens in
+**   phrase iPhrase of the query. Phrases are numbered starting from zero.
+**
+** xInstCount:
+**   Set *pnInst to the total number of occurrences of all phrases within
+**   the query within the current row. Return SQLITE_OK if successful, or
+**   an error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always returns 0.
+**
+** xInst:
+**   Query for the details of phrase match iIdx within the current row.
+**   Phrase matches are numbered starting from zero, so the iIdx argument
+**   should be greater than or equal to zero and smaller than the value
+**   output by xInstCount(). If iIdx is less than zero or greater than
+**   or equal to the value returned by xInstCount(), SQLITE_RANGE is returned.
+**
+**   Otherwise, output parameter *piPhrase is set to the phrase number, *piCol
+**   to the column in which it occurs and *piOff the token offset of the
+**   first token of the phrase. SQLITE_OK is returned if successful, or an
+**   error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xRowid:
+**   Returns the rowid of the current row.
+**
+** xTokenize:
+**   Tokenize text using the tokenizer belonging to the FTS5 table.
+**
+** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
+**   This API function is used to query the FTS table for phrase iPhrase
+**   of the current query. Specifically, a query equivalent to:
+**
+**       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
+**
+**   with $p set to a phrase equivalent to the phrase iPhrase of the
+**   current query is executed. Any column filter that applies to
+**   phrase iPhrase of the current query is included in $p. For each
+**   row visited, the callback function passed as the fourth argument
+**   is invoked. The context and API objects passed to the callback
+**   function may be used to access the properties of each matched row.
+**   Invoking Api.xUserData() returns a copy of the pointer passed as
+**   the third argument to pUserData.
+**
+**   If parameter iPhrase is less than zero, or greater than or equal to
+**   the number of phrases in the query, as returned by xPhraseCount(),
+**   this function returns SQLITE_RANGE.
+**
+**   If the callback function returns any value other than SQLITE_OK, the
+**   query is abandoned and the xQueryPhrase function returns immediately.
+**   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
+**   Otherwise, the error code is propagated upwards.
+**
+**   If the query runs to completion without incident, SQLITE_OK is returned.
+**   Or, if some error occurs before the query completes or is aborted by
+**   the callback, an SQLite error code is returned.
+**
+**
+** xSetAuxdata(pFts5, pAux, xDelete)
+**
+**   Save the pointer passed as the second argument as the extension function's
+**   "auxiliary data". The pointer may then be retrieved by the current or any
+**   future invocation of the same fts5 extension function made as part of
+**   the same MATCH query using the xGetAuxdata() API.
+**
+**   Each extension function is allocated a single auxiliary data slot for
+**   each FTS query (MATCH expression). If the extension function is invoked
+**   more than once for a single FTS query, then all invocations share a
+**   single auxiliary data context.
+**
+**   If there is already an auxiliary data pointer when this function is
+**   invoked, then it is replaced by the new pointer. If an xDelete callback
+**   was specified along with the original pointer, it is invoked at this
+**   point.
+**
+**   The xDelete callback, if one is specified, is also invoked on the
+**   auxiliary data pointer after the FTS5 query has finished.
+**
+**   If an error (e.g. an OOM condition) occurs within this function,
+**   the auxiliary data is set to NULL and an error code returned. If the
+**   xDelete parameter was not NULL, it is invoked on the auxiliary data
+**   pointer before returning.
+**
+**
+** xGetAuxdata(pFts5, bClear)
+**
+**   Returns the current auxiliary data pointer for the fts5 extension
+**   function. See the xSetAuxdata() method for details.
+**
+**   If the bClear argument is non-zero, then the auxiliary data is cleared
+**   (set to NULL) before this function returns. In this case the xDelete,
+**   if any, is not invoked.
+**
+**
+** xRowCount(pFts5, pnRow)
+**
+**   This function is used to retrieve the total number of rows in the table.
+**   In other words, the same value that would be returned by:
+**
+**        SELECT count(*) FROM ftstable;
+**
+** xPhraseFirst()
+**   This function is used, along with type Fts5PhraseIter and the xPhraseNext
+**   method, to iterate through all instances of a single query phrase within
+**   the current row. This is the same information as is accessible via the
+**   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
+**   to use, this API may be faster under some circumstances. To iterate
+**   through instances of phrase iPhrase, use the following code:
+**
+**       Fts5PhraseIter iter;
+**       int iCol, iOff;
+**       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
+**           iCol>=0;
+**           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
+**       ){
+**         // An instance of phrase iPhrase at offset iOff of column iCol
+**       }
+**
+**   The Fts5PhraseIter structure is defined above. Applications should not
+**   modify this structure directly - it should only be used as shown above
+**   with the xPhraseFirst() and xPhraseNext() API methods (and by
+**   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always iterates
+**   through an empty set (all calls to xPhraseFirst() set iCol to -1).
+**
+**   In all cases, matches are visited in (column ASC, offset ASC) order.
+**   i.e. all those in column 0, sorted by offset, followed by those in
+**   column 1, etc.
+**
+** xPhraseNext()
+**   See xPhraseFirst above.
+**
+** xPhraseFirstColumn()
+**   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
+**   and xPhraseNext() APIs described above. The difference is that instead
+**   of iterating through all instances of a phrase in the current row, these
+**   APIs are used to iterate through the set of columns in the current row
+**   that contain one or more instances of a specified phrase. For example:
+**
+**       Fts5PhraseIter iter;
+**       int iCol;
+**       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
+**           iCol>=0;
+**           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
+**       ){
+**         // Column iCol contains at least one instance of phrase iPhrase
+**       }
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" option. If the FTS5 table is created with either
+**   "detail=none" "content=" option (i.e. if it is a contentless table),
+**   then this API always iterates through an empty set (all calls to
+**   xPhraseFirstColumn() set iCol to -1).
+**
+**   The information accessed using this API and its companion
+**   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
+**   (or xInst/xInstCount). The chief advantage of this API is that it is
+**   significantly more efficient than those alternatives when used with
+**   "detail=column" tables.
+**
+** xPhraseNextColumn()
+**   See xPhraseFirstColumn above.
+**
+** xQueryToken(pFts5, iPhrase, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase iPhrase of the current
+**   query. Before returning, output parameter *ppToken is set to point
+**   to a buffer containing the requested token, and *pnToken to the
+**   size of this buffer in bytes.
+**
+**   If iPhrase or iToken are less than zero, or if iPhrase is greater than
+**   or equal to the number of phrases in the query as reported by
+**   xPhraseCount(), or if iToken is equal to or greater than the number of
+**   tokens in the phrase, SQLITE_RANGE is returned and *ppToken and *pnToken
+     are both zeroed.
+**
+**   The output text is not a copy of the query text that specified the
+**   token. It is the output of the tokenizer module. For tokendata=1
+**   tables, this includes any embedded 0x00 and trailing data.
+**
+** xInstToken(pFts5, iIdx, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase hit iIdx within the
+**   current row. If iIdx is less than zero or greater than or equal to the
+**   value returned by xInstCount(), SQLITE_RANGE is returned.  Otherwise,
+**   output variable (*ppToken) is set to point to a buffer containing the
+**   matching document token, and (*pnToken) to the size of that buffer in
+**   bytes.
+**
+**   The output text is not a copy of the document text that was tokenized.
+**   It is the output of the tokenizer module. For tokendata=1 tables, this
+**   includes any embedded 0x00 and trailing data.
+**
+**   This API may be slow in some cases if the token identified by parameters
+**   iIdx and iToken matched a prefix token in the query. In most cases, the
+**   first call to this API for each prefix token in the query is forced
+**   to scan the portion of the full-text index that matches the prefix
+**   token to collect the extra data required by this API. If the prefix
+**   token matches a large number of token instances in the document set,
+**   this may be a performance problem.
+**
+**   If the user knows in advance that a query may use this API for a
+**   prefix token, FTS5 may be configured to collect all required data as part
+**   of the initial querying of the full-text index, avoiding the second scan
+**   entirely. This also causes prefix queries that do not use this API to
+**   run more slowly and use more memory. FTS5 may be configured in this way
+**   either on a per-table basis using the [FTS5 insttoken | 'insttoken']
+**   option, or on a per-query basis using the
+**   [fts5_insttoken | fts5_insttoken()] user function.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xColumnLocale(pFts5, iIdx, pzLocale, pnLocale)
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the locale associated
+**   with column iCol of the current row. Usually, there is no associated
+**   locale, and output parameters (*pzLocale) and (*pnLocale) are set
+**   to NULL and 0, respectively. However, if the fts5_locale() function
+**   was used to associate a locale with the value when it was inserted
+**   into the fts5 table, then (*pzLocale) is set to point to a nul-terminated
+**   buffer containing the name of the locale in utf-8 encoding. (*pnLocale)
+**   is set to the size in bytes of the buffer, not including the
+**   nul-terminator.
+**
+**   If successful, SQLITE_OK is returned. Or, if an error occurs, an
+**   SQLite error code is returned. The final value of the output parameters
+**   is undefined in this case.
+**
+** xTokenize_v2:
+**   Tokenize text using the tokenizer belonging to the FTS5 table. This
+**   API is the same as the xTokenize() API, except that it allows a tokenizer
+**   locale to be specified.
+*/
+struct Fts5ExtensionApi {
+  int iVersion;                   /* Currently always set to 4 */
+
+  void *(*xUserData)(Fts5Context*);
+
+  int (*xColumnCount)(Fts5Context*);
+  int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
+  int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
+
+  int (*xTokenize)(Fts5Context*,
+    const char *pText, int nText, /* Text to tokenize */
+    void *pCtx,                   /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+
+  int (*xPhraseCount)(Fts5Context*);
+  int (*xPhraseSize)(Fts5Context*, int iPhrase);
+
+  int (*xInstCount)(Fts5Context*, int *pnInst);
+  int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
+
+  sqlite3_int64 (*xRowid)(Fts5Context*);
+  int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
+
+  int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
+    int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
+  );
+  int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
+  void *(*xGetAuxdata)(Fts5Context*, int bClear);
+
+  int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
+  void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
+
+  int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
+  void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
+
+  /* Below this point are iVersion>=3 only */
+  int (*xQueryToken)(Fts5Context*,
+      int iPhrase, int iToken,
+      const char **ppToken, int *pnToken
+  );
+  int (*xInstToken)(Fts5Context*, int iIdx, int iToken, const char**, int*);
+
+  /* Below this point are iVersion>=4 only */
+  int (*xColumnLocale)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xTokenize_v2)(Fts5Context*,
+    const char *pText, int nText,      /* Text to tokenize */
+    const char *pLocale, int nLocale,  /* Locale to pass to tokenizer */
+    void *pCtx,                        /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+};
+
+/*
+** CUSTOM AUXILIARY FUNCTIONS
+*************************************************************************/
+
+/*************************************************************************
+** CUSTOM TOKENIZERS
+**
+** Applications may also register custom tokenizer types. A tokenizer
+** is registered by providing fts5 with a populated instance of the
+** following structure. All structure methods must be defined, setting
+** any member of the fts5_tokenizer struct to NULL leads to undefined
+** behaviour. The structure methods are expected to function as follows:
+**
+** xCreate:
+**   This function is used to allocate and initialize a tokenizer instance.
+**   A tokenizer instance is required to actually tokenize text.
+**
+**   The first argument passed to this function is a copy of the (void*)
+**   pointer provided by the application when the fts5_tokenizer_v2 object
+**   was registered with FTS5 (the third argument to xCreateTokenizer()).
+**   The second and third arguments are an array of nul-terminated strings
+**   containing the tokenizer arguments, if any, specified following the
+**   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
+**   to create the FTS5 table.
+**
+**   The final argument is an output variable. If successful, (*ppOut)
+**   should be set to point to the new tokenizer handle and SQLITE_OK
+**   returned. If an error occurs, some value other than SQLITE_OK should
+**   be returned. In this case, fts5 assumes that the final value of *ppOut
+**   is undefined.
+**
+** xDelete:
+**   This function is invoked to delete a tokenizer handle previously
+**   allocated using xCreate(). Fts5 guarantees that this function will
+**   be invoked exactly once for each successful call to xCreate().
+**
+** xTokenize:
+**   This function is expected to tokenize the nText byte string indicated
+**   by argument pText. pText may or may not be nul-terminated. The first
+**   argument passed to this function is a pointer to an Fts5Tokenizer object
+**   returned by an earlier call to xCreate().
+**
+**   The third argument indicates the reason that FTS5 is requesting
+**   tokenization of the supplied text. This is always one of the following
+**   four values:
+**
+**   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
+**            or removed from the FTS table. The tokenizer is being invoked to
+**            determine the set of tokens to add to (or delete from) the
+**            FTS index.
+**
+**       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
+**            against the FTS index. The tokenizer is being called to tokenize
+**            a bareword or quoted string specified as part of the query.
+**
+**       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
+**            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
+**            followed by a "*" character, indicating that the last token
+**            returned by the tokenizer will be treated as a token prefix.
+**
+**       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
+**            satisfy an fts5_api.xTokenize() request made by an auxiliary
+**            function. Or an fts5_api.xColumnSize() request made by the same
+**            on a columnsize=0 database.
+**   </ul>
+**
+**   The sixth and seventh arguments passed to xTokenize() - pLocale and
+**   nLocale - are a pointer to a buffer containing the locale to use for
+**   tokenization (e.g. "en_US") and its size in bytes, respectively. The
+**   pLocale buffer is not nul-terminated. pLocale may be passed NULL (in
+**   which case nLocale is always 0) to indicate that the tokenizer should
+**   use its default locale.
+**
+**   For each token in the input string, the supplied callback xToken() must
+**   be invoked. The first argument to it should be a copy of the pointer
+**   passed as the second argument to xTokenize(). The third and fourth
+**   arguments are a pointer to a buffer containing the token text, and the
+**   size of the token in bytes. The 4th and 5th arguments are the byte offsets
+**   of the first byte of and first byte immediately following the text from
+**   which the token is derived within the input.
+**
+**   The second argument passed to the xToken() callback ("tflags") should
+**   normally be set to 0. The exception is if the tokenizer supports
+**   synonyms. In this case see the discussion below for details.
+**
+**   FTS5 assumes the xToken() callback is invoked for each token in the
+**   order that they occur within the input text.
+**
+**   If an xToken() callback returns any value other than SQLITE_OK, then
+**   the tokenization should be abandoned and the xTokenize() method should
+**   immediately return a copy of the xToken() return value. Or, if the
+**   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
+**   if an error occurs with the xTokenize() implementation itself, it
+**   may abandon the tokenization and return any error code other than
+**   SQLITE_OK or SQLITE_DONE.
+**
+**   If the tokenizer is registered using an fts5_tokenizer_v2 object,
+**   then the xTokenize() method has two additional arguments - pLocale
+**   and nLocale. These specify the locale that the tokenizer should use
+**   for the current request. If pLocale and nLocale are both 0, then the
+**   tokenizer should use its default locale. Otherwise, pLocale points to
+**   an nLocale byte buffer containing the name of the locale to use as utf-8
+**   text. pLocale is not nul-terminated.
+**
+** FTS5_TOKENIZER
+**
+** There is also an fts5_tokenizer object. This is an older, deprecated,
+** version of fts5_tokenizer_v2. It is similar except that:
+**
+**  <ul>
+**    <li> There is no "iVersion" field, and
+**    <li> The xTokenize() method does not take a locale argument.
+**  </ul>
+**
+** Legacy fts5_tokenizer tokenizers must be registered using the
+** legacy xCreateTokenizer() function, instead of xCreateTokenizer_v2().
+**
+** Tokenizer implementations registered using either API may be retrieved
+** using both xFindTokenizer() and xFindTokenizer_v2().
+**
+** SYNONYM SUPPORT
+**
+**   Custom tokenizers may also support synonyms. Consider a case in which a
+**   user wishes to query for a phrase such as "first place". Using the
+**   built-in tokenizers, the FTS5 query 'first + place' will match instances
+**   of "first place" within the document set, but not alternative forms
+**   such as "1st place". In some applications, it would be better to match
+**   all instances of "first place" or "1st place" regardless of which form
+**   the user specified in the MATCH query text.
+**
+**   There are several ways to approach this in FTS5:
+**
+**   <ol><li> By mapping all synonyms to a single token. In this case, using
+**            the above example, this means that the tokenizer returns the
+**            same token for inputs "first" and "1st". Say that token is in
+**            fact "first", so that when the user inserts the document "I won
+**            1st place" entries are added to the index for tokens "i", "won",
+**            "first" and "place". If the user then queries for '1st + place',
+**            the tokenizer substitutes "first" for "1st" and the query works
+**            as expected.
+**
+**       <li> By querying the index for all synonyms of each query term
+**            separately. In this case, when tokenizing query text, the
+**            tokenizer may provide multiple synonyms for a single term
+**            within the document. FTS5 then queries the index for each
+**            synonym individually. For example, faced with the query:
+**
+**   <codeblock>
+**     ... MATCH 'first place'</codeblock>
+**
+**            the tokenizer offers both "1st" and "first" as synonyms for the
+**            first token in the MATCH query and FTS5 effectively runs a query
+**            similar to:
+**
+**   <codeblock>
+**     ... MATCH '(first OR 1st) place'</codeblock>
+**
+**            except that, for the purposes of auxiliary functions, the query
+**            still appears to contain just two phrases - "(first OR 1st)"
+**            being treated as a single phrase.
+**
+**       <li> By adding multiple synonyms for a single term to the FTS index.
+**            Using this method, when tokenizing document text, the tokenizer
+**            provides multiple synonyms for each token. So that when a
+**            document such as "I won first place" is tokenized, entries are
+**            added to the FTS index for "i", "won", "first", "1st" and
+**            "place".
+**
+**            This way, even if the tokenizer does not provide synonyms
+**            when tokenizing query text (it should not - to do so would be
+**            inefficient), it doesn't matter if the user queries for
+**            'first + place' or '1st + place', as there are entries in the
+**            FTS index corresponding to both forms of the first token.
+**   </ol>
+**
+**   Whether it is parsing document or query text, any call to xToken that
+**   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
+**   is considered to supply a synonym for the previous token. For example,
+**   when parsing the document "I won first place", a tokenizer that supports
+**   synonyms would call xToken() 5 times, as follows:
+**
+**   <codeblock>
+**       xToken(pCtx, 0, "i",                      1,  0,  1);
+**       xToken(pCtx, 0, "won",                    3,  2,  5);
+**       xToken(pCtx, 0, "first",                  5,  6, 11);
+**       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
+**       xToken(pCtx, 0, "place",                  5, 12, 17);
+**</codeblock>
+**
+**   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
+**   xToken() is called. Multiple synonyms may be specified for a single token
+**   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
+**   There is no limit to the number of synonyms that may be provided for a
+**   single token.
+**
+**   In many cases, method (1) above is the best approach. It does not add
+**   extra data to the FTS index or require FTS5 to query for multiple terms,
+**   so it is efficient in terms of disk space and query speed. However, it
+**   does not support prefix queries very well. If, as suggested above, the
+**   token "first" is substituted for "1st" by the tokenizer, then the query:
+**
+**   <codeblock>
+**     ... MATCH '1s*'</codeblock>
+**
+**   will not match documents that contain the token "1st" (as the tokenizer
+**   will probably not map "1s" to any prefix of "first").
+**
+**   For full prefix support, method (3) may be preferred. In this case,
+**   because the index contains entries for both "first" and "1st", prefix
+**   queries such as 'fi*' or '1s*' will match correctly. However, because
+**   extra entries are added to the FTS index, this method uses more space
+**   within the database.
+**
+**   Method (2) offers a midpoint between (1) and (3). Using this method,
+**   a query such as '1s*' will match documents that contain the literal
+**   token "1st", but not "first" (assuming the tokenizer is not able to
+**   provide synonyms for prefixes). However, a non-prefix query like '1st'
+**   will match against "1st" and "first". This method does not require
+**   extra disk space, as no extra entries are added to the FTS index.
+**   On the other hand, it may require more CPU cycles to run MATCH queries,
+**   as separate queries of the FTS index are required for each synonym.
+**
+**   When using methods (2) or (3), it is important that the tokenizer only
+**   provide synonyms when tokenizing document text (method (3)) or query
+**   text (method (2)), not both. Doing so will not cause any errors, but is
+**   inefficient.
+*/
+typedef struct Fts5Tokenizer Fts5Tokenizer;
+typedef struct fts5_tokenizer_v2 fts5_tokenizer_v2;
+struct fts5_tokenizer_v2 {
+  int iVersion;             /* Currently always 2 */
+
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      const char *pLocale, int nLocale,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+/*
+** New code should use the fts5_tokenizer_v2 type to define tokenizer
+** implementations. The following type is included for legacy applications
+** that still use it.
+*/
+typedef struct fts5_tokenizer fts5_tokenizer;
+struct fts5_tokenizer {
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+
+/* Flags that may be passed as the third argument to xTokenize() */
+#define FTS5_TOKENIZE_QUERY     0x0001
+#define FTS5_TOKENIZE_PREFIX    0x0002
+#define FTS5_TOKENIZE_DOCUMENT  0x0004
+#define FTS5_TOKENIZE_AUX       0x0008
+
+/* Flags that may be passed by the tokenizer implementation back to FTS5
+** as the third argument to the supplied xToken callback. */
+#define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
+
+/*
+** END OF CUSTOM TOKENIZERS
+*************************************************************************/
+
+/*************************************************************************
+** FTS5 EXTENSION REGISTRATION API
+*/
+typedef struct fts5_api fts5_api;
+struct fts5_api {
+  int iVersion;                   /* Currently always set to 3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer *pTokenizer
+  );
+
+  /* Create a new auxiliary function */
+  int (*xCreateFunction)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_extension_function xFunction,
+    void (*xDestroy)(void*)
+  );
+
+  /* APIs below this point are only available if iVersion>=3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer_v2 *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer_v2 **ppTokenizer
+  );
+};
+
+/*
+** END OF REGISTRATION API
+*************************************************************************/
+
+#if 0
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* _FTS5_H */
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+#ifndef _FTS5INT_H
+#define _FTS5INT_H
+
+/* #include "fts5.h" */
+/* #include "sqlite3ext.h" */
+SQLITE_EXTENSION_INIT1
+
+/* #include <string.h> */
+/* #include <assert.h> */
+
+#ifndef SQLITE_AMALGAMATION
+
+typedef unsigned char  u8;
+typedef unsigned int   u32;
+typedef unsigned short u16;
+typedef short i16;
+typedef sqlite3_int64 i64;
+typedef sqlite3_uint64 u64;
+
+#ifndef ArraySize
+# define ArraySize(x) ((int)(sizeof(x) / sizeof(x[0])))
+#endif
+
+#define testcase(x)
+
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
+# define SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS 1
+#endif
+#if defined(SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS)
+# define ALWAYS(X)      (1)
+# define NEVER(X)       (0)
+#elif !defined(NDEBUG)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
+#else
+# define ALWAYS(X)      (X)
+# define NEVER(X)       (X)
+#endif
+
+#define MIN(x,y) (((x) < (y)) ? (x) : (y))
+#define MAX(x,y) (((x) > (y)) ? (x) : (y))
+
+/*
+** Constants for the largest and smallest possible 64-bit signed integers.
+*/
+# define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
+# define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
+
+/* The uptr type is an unsigned integer large enough to hold a pointer
+*/
+#if defined(HAVE_STDINT_H)
+  typedef uintptr_t uptr;
+#elif SQLITE_PTRSIZE==4
+  typedef u32 uptr;
+#else
+  typedef u64 uptr;
+#endif
+
+#ifdef SQLITE_4_BYTE_ALIGNED_MALLOC
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&3)==0)
+#else
+# define EIGHT_BYTE_ALIGNMENT(X)   ((((uptr)(X) - (uptr)0)&7)==0)
+#endif
+
+#endif
+
+/* Truncate very long tokens to this many bytes. Hard limit is
+** (65536-1-1-4-9)==65521 bytes. The limiting factor is the 16-bit offset
+** field that occurs at the start of each leaf page (see fts5_index.c). */
+#define FTS5_MAX_TOKEN_SIZE 32768
+
+/*
+** Maximum number of prefix indexes on single FTS5 table. This must be
+** less than 32. If it is set to anything large than that, an #error
+** directive in fts5_index.c will cause the build to fail.
+*/
+#define FTS5_MAX_PREFIX_INDEXES 31
+
+/*
+** Maximum segments permitted in a single index
+*/
+#define FTS5_MAX_SEGMENT 2000
+
+#define FTS5_DEFAULT_NEARDIST 10
+#define FTS5_DEFAULT_RANK     "bm25"
+
+/* Name of rank and rowid columns */
+#define FTS5_RANK_NAME "rank"
+#define FTS5_ROWID_NAME "rowid"
+
+#ifdef SQLITE_DEBUG
+# define FTS5_CORRUPT sqlite3Fts5Corrupt()
+static int sqlite3Fts5Corrupt(void);
+#else
+# define FTS5_CORRUPT SQLITE_CORRUPT_VTAB
+#endif
+
+/*
+** The assert_nc() macro is similar to the assert() macro, except that it
+** is used for assert() conditions that are true only if it can be
+** guranteed that the database is not corrupt.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_API extern int sqlite3_fts5_may_be_corrupt;
+# define assert_nc(x) assert(sqlite3_fts5_may_be_corrupt || (x))
+#else
+# define assert_nc(x) assert(x)
+#endif
+
+/*
+** A version of memcmp() that does not cause asan errors if one of the pointer
+** parameters is NULL and the number of bytes to compare is zero.
+*/
+#define fts5Memcmp(s1, s2, n) ((n)<=0 ? 0 : memcmp((s1), (s2), (n)))
+
+/* Mark a function parameter as unused, to suppress nuisance compiler
+** warnings. */
+#ifndef UNUSED_PARAM
+# define UNUSED_PARAM(X)  (void)(X)
+#endif
+
+#ifndef UNUSED_PARAM2
+# define UNUSED_PARAM2(X, Y)  (void)(X), (void)(Y)
+#endif
+
+typedef struct Fts5Global Fts5Global;
+typedef struct Fts5Colset Fts5Colset;
+
+/* If a NEAR() clump or phrase may only match a specific set of columns,
+** then an object of the following type is used to record the set of columns.
+** Each entry in the aiCol[] array is a column that may be matched.
+**
+** This object is used by fts5_expr.c and fts5_index.c.
+*/
+struct Fts5Colset {
+  int nCol;
+  int aiCol[1];
+};
+
+
+
+/**************************************************************************
+** Interface to code in fts5_config.c. fts5_config.c contains contains code
+** to parse the arguments passed to the CREATE VIRTUAL TABLE statement.
+*/
+
+typedef struct Fts5Config Fts5Config;
+typedef struct Fts5TokenizerConfig Fts5TokenizerConfig;
+
+struct Fts5TokenizerConfig {
+  Fts5Tokenizer *pTok;
+  fts5_tokenizer_v2 *pApi2;
+  fts5_tokenizer *pApi1;
+  const char **azArg;
+  int nArg;
+  int ePattern;                   /* FTS_PATTERN_XXX constant */
+  const char *pLocale;            /* Current locale to use */
+  int nLocale;                    /* Size of pLocale in bytes */
+};
+
+/*
+** An instance of the following structure encodes all information that can
+** be gleaned from the CREATE VIRTUAL TABLE statement.
+**
+** And all information loaded from the %_config table.
+**
+** nAutomerge:
+**   The minimum number of segments that an auto-merge operation should
+**   attempt to merge together. A value of 1 sets the object to use the
+**   compile time default. Zero disables auto-merge altogether.
+**
+** bContentlessDelete:
+**   True if the contentless_delete option was present in the CREATE
+**   VIRTUAL TABLE statement.
+**
+** zContent:
+**
+** zContentRowid:
+**   The value of the content_rowid= option, if one was specified. Or
+**   the string "rowid" otherwise. This text is not quoted - if it is
+**   used as part of an SQL statement it needs to be quoted appropriately.
+**
+** zContentExprlist:
+**
+** pzErrmsg:
+**   This exists in order to allow the fts5_index.c module to return a
+**   decent error message if it encounters a file-format version it does
+**   not understand.
+**
+** bColumnsize:
+**   True if the %_docsize table is created.
+**
+** bPrefixIndex:
+**   This is only used for debugging. If set to false, any prefix indexes
+**   are ignored. This value is configured using:
+**
+**       INSERT INTO tbl(tbl, rank) VALUES('prefix-index', $bPrefixIndex);
+**
+** bLocale:
+**   Set to true if locale=1 was specified when the table was created.
+*/
+struct Fts5Config {
+  sqlite3 *db;                    /* Database handle */
+  Fts5Global *pGlobal;            /* Global fts5 object for handle db */
+  char *zDb;                      /* Database holding FTS index (e.g. "main") */
+  char *zName;                    /* Name of FTS index */
+  int nCol;                       /* Number of columns */
+  char **azCol;                   /* Column names */
+  u8 *abUnindexed;                /* True for unindexed columns */
+  int nPrefix;                    /* Number of prefix indexes */
+  int *aPrefix;                   /* Sizes in bytes of nPrefix prefix indexes */
+  int eContent;                   /* An FTS5_CONTENT value */
+  int bContentlessDelete;         /* "contentless_delete=" option (dflt==0) */
+  int bContentlessUnindexed;      /* "contentless_unindexed=" option (dflt=0) */
+  char *zContent;                 /* content table */
+  char *zContentRowid;            /* "content_rowid=" option value */
+  int bColumnsize;                /* "columnsize=" option value (dflt==1) */
+  int bTokendata;                 /* "tokendata=" option value (dflt==0) */
+  int bLocale;                    /* "locale=" option value (dflt==0) */
+  int eDetail;                    /* FTS5_DETAIL_XXX value */
+  char *zContentExprlist;
+  Fts5TokenizerConfig t;
+  int bLock;                      /* True when table is preparing statement */
+
+
+  /* Values loaded from the %_config table */
+  int iVersion;                   /* fts5 file format 'version' */
+  int iCookie;                    /* Incremented when %_config is modified */
+  int pgsz;                       /* Approximate page size used in %_data */
+  int nAutomerge;                 /* 'automerge' setting */
+  int nCrisisMerge;               /* Maximum allowed segments per level */
+  int nUsermerge;                 /* 'usermerge' setting */
+  int nHashSize;                  /* Bytes of memory for in-memory hash */
+  char *zRank;                    /* Name of rank function */
+  char *zRankArgs;                /* Arguments to rank function */
+  int bSecureDelete;              /* 'secure-delete' */
+  int nDeleteMerge;               /* 'deletemerge' */
+  int bPrefixInsttoken;           /* 'prefix-insttoken' */
+
+  /* If non-NULL, points to sqlite3_vtab.base.zErrmsg. Often NULL. */
+  char **pzErrmsg;
+
+#ifdef SQLITE_DEBUG
+  int bPrefixIndex;               /* True to use prefix-indexes */
+#endif
+};
+
+/* Current expected value of %_config table 'version' field. And
+** the expected version if the 'secure-delete' option has ever been
+** set on the table.  */
+#define FTS5_CURRENT_VERSION               4
+#define FTS5_CURRENT_VERSION_SECUREDELETE  5
+
+#define FTS5_CONTENT_NORMAL    0
+#define FTS5_CONTENT_NONE      1
+#define FTS5_CONTENT_EXTERNAL  2
+#define FTS5_CONTENT_UNINDEXED 3
+
+#define FTS5_DETAIL_FULL      0
+#define FTS5_DETAIL_NONE      1
+#define FTS5_DETAIL_COLUMNS   2
+
+#define FTS5_PATTERN_NONE     0
+#define FTS5_PATTERN_LIKE     65  /* matches SQLITE_INDEX_CONSTRAINT_LIKE */
+#define FTS5_PATTERN_GLOB     66  /* matches SQLITE_INDEX_CONSTRAINT_GLOB */
+
+static int sqlite3Fts5ConfigParse(
+    Fts5Global*, sqlite3*, int, const char **, Fts5Config**, char**
+);
+static void sqlite3Fts5ConfigFree(Fts5Config*);
+
+static int sqlite3Fts5ConfigDeclareVtab(Fts5Config *pConfig);
+
+static int sqlite3Fts5Tokenize(
+  Fts5Config *pConfig,            /* FTS5 Configuration object */
+  int flags,                      /* FTS5_TOKENIZE_* flags */
+  const char *pText, int nText,   /* Text to tokenize */
+  void *pCtx,                     /* Context passed to xToken() */
+  int (*xToken)(void*, int, const char*, int, int, int)    /* Callback */
+);
+
+static void sqlite3Fts5Dequote(char *z);
+
+/* Load the contents of the %_config table */
+static int sqlite3Fts5ConfigLoad(Fts5Config*, int);
+
+/* Set the value of a single config attribute */
+static int sqlite3Fts5ConfigSetValue(Fts5Config*, const char*, sqlite3_value*, int*);
+
+static int sqlite3Fts5ConfigParseRank(const char*, char**, char**);
+
+static void sqlite3Fts5ConfigErrmsg(Fts5Config *pConfig, const char *zFmt, ...);
+
+/*
+** End of interface to code in fts5_config.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_buffer.c.
+*/
+
+/*
+** Buffer object for the incremental building of string data.
+*/
+typedef struct Fts5Buffer Fts5Buffer;
+struct Fts5Buffer {
+  u8 *p;
+  int n;
+  int nSpace;
+};
+
+static int sqlite3Fts5BufferSize(int*, Fts5Buffer*, u32);
+static void sqlite3Fts5BufferAppendVarint(int*, Fts5Buffer*, i64);
+static void sqlite3Fts5BufferAppendBlob(int*, Fts5Buffer*, u32, const u8*);
+static void sqlite3Fts5BufferAppendString(int *, Fts5Buffer*, const char*);
+static void sqlite3Fts5BufferFree(Fts5Buffer*);
+static void sqlite3Fts5BufferZero(Fts5Buffer*);
+static void sqlite3Fts5BufferSet(int*, Fts5Buffer*, int, const u8*);
+static void sqlite3Fts5BufferAppendPrintf(int *, Fts5Buffer*, char *zFmt, ...);
+
+static char *sqlite3Fts5Mprintf(int *pRc, const char *zFmt, ...);
+
+#define fts5BufferZero(x)             sqlite3Fts5BufferZero(x)
+#define fts5BufferAppendVarint(a,b,c) sqlite3Fts5BufferAppendVarint(a,b,(i64)c)
+#define fts5BufferFree(a)             sqlite3Fts5BufferFree(a)
+#define fts5BufferAppendBlob(a,b,c,d) sqlite3Fts5BufferAppendBlob(a,b,c,d)
+#define fts5BufferSet(a,b,c,d)        sqlite3Fts5BufferSet(a,b,c,d)
+
+#define fts5BufferGrow(pRc,pBuf,nn) ( \
+  (u32)((pBuf)->n) + (u32)(nn) <= (u32)((pBuf)->nSpace) ? 0 : \
+    sqlite3Fts5BufferSize((pRc),(pBuf),(nn)+(pBuf)->n) \
+)
+
+/* Write and decode big-endian 32-bit integer values */
+static void sqlite3Fts5Put32(u8*, int);
+static int sqlite3Fts5Get32(const u8*);
+
+#define FTS5_POS2COLUMN(iPos) (int)((iPos >> 32) & 0x7FFFFFFF)
+#define FTS5_POS2OFFSET(iPos) (int)(iPos & 0x7FFFFFFF)
+
+typedef struct Fts5PoslistReader Fts5PoslistReader;
+struct Fts5PoslistReader {
+  /* Variables used only by sqlite3Fts5PoslistIterXXX() functions. */
+  const u8 *a;                    /* Position list to iterate through */
+  int n;                          /* Size of buffer at a[] in bytes */
+  int i;                          /* Current offset in a[] */
+
+  u8 bFlag;                       /* For client use (any custom purpose) */
+
+  /* Output variables */
+  u8 bEof;                        /* Set to true at EOF */
+  i64 iPos;                       /* (iCol<<32) + iPos */
+};
+static int sqlite3Fts5PoslistReaderInit(
+  const u8 *a, int n,             /* Poslist buffer to iterate through */
+  Fts5PoslistReader *pIter        /* Iterator object to initialize */
+);
+static int sqlite3Fts5PoslistReaderNext(Fts5PoslistReader*);
+
+typedef struct Fts5PoslistWriter Fts5PoslistWriter;
+struct Fts5PoslistWriter {
+  i64 iPrev;
+};
+static int sqlite3Fts5PoslistWriterAppend(Fts5Buffer*, Fts5PoslistWriter*, i64);
+static void sqlite3Fts5PoslistSafeAppend(Fts5Buffer*, i64*, i64);
+
+static int sqlite3Fts5PoslistNext64(
+  const u8 *a, int n,             /* Buffer containing poslist */
+  int *pi,                        /* IN/OUT: Offset within a[] */
+  i64 *piOff                      /* IN/OUT: Current offset */
+);
+
+/* Malloc utility */
+static void *sqlite3Fts5MallocZero(int *pRc, sqlite3_int64 nByte);
+static char *sqlite3Fts5Strndup(int *pRc, const char *pIn, int nIn);
+
+/* Character set tests (like isspace(), isalpha() etc.) */
+static int sqlite3Fts5IsBareword(char t);
+
+
+/* Bucket of terms object used by the integrity-check in offsets=0 mode. */
+typedef struct Fts5Termset Fts5Termset;
+static int sqlite3Fts5TermsetNew(Fts5Termset**);
+static int sqlite3Fts5TermsetAdd(Fts5Termset*, int, const char*, int, int *pbPresent);
+static void sqlite3Fts5TermsetFree(Fts5Termset*);
+
+/*
+** End of interface to code in fts5_buffer.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_index.c. fts5_index.c contains contains code
+** to access the data stored in the %_data table.
+*/
+
+typedef struct Fts5Index Fts5Index;
+typedef struct Fts5IndexIter Fts5IndexIter;
+
+struct Fts5IndexIter {
+  i64 iRowid;
+  const u8 *pData;
+  int nData;
+  u8 bEof;
+};
+
+#define sqlite3Fts5IterEof(x) ((x)->bEof)
+
+/*
+** Values used as part of the flags argument passed to IndexQuery().
+*/
+#define FTS5INDEX_QUERY_PREFIX      0x0001  /* Prefix query */
+#define FTS5INDEX_QUERY_DESC        0x0002  /* Docs in descending rowid order */
+#define FTS5INDEX_QUERY_TEST_NOIDX  0x0004  /* Do not use prefix index */
+#define FTS5INDEX_QUERY_SCAN        0x0008  /* Scan query (fts5vocab) */
+
+/* The following are used internally by the fts5_index.c module. They are
+** defined here only to make it easier to avoid clashes with the flags
+** above. */
+#define FTS5INDEX_QUERY_SKIPEMPTY   0x0010
+#define FTS5INDEX_QUERY_NOOUTPUT    0x0020
+#define FTS5INDEX_QUERY_SKIPHASH    0x0040
+#define FTS5INDEX_QUERY_NOTOKENDATA 0x0080
+#define FTS5INDEX_QUERY_SCANONETERM 0x0100
+
+/*
+** Create/destroy an Fts5Index object.
+*/
+static int sqlite3Fts5IndexOpen(Fts5Config *pConfig, int bCreate, Fts5Index**, char**);
+static int sqlite3Fts5IndexClose(Fts5Index *p);
+
+/*
+** Return a simple checksum value based on the arguments.
+*/
+static u64 sqlite3Fts5IndexEntryCksum(
+  i64 iRowid,
+  int iCol,
+  int iPos,
+  int iIdx,
+  const char *pTerm,
+  int nTerm
+);
+
+/*
+** Argument p points to a buffer containing utf-8 text that is n bytes in
+** size. Return the number of bytes in the nChar character prefix of the
+** buffer, or 0 if there are less than nChar characters in total.
+*/
+static int sqlite3Fts5IndexCharlenToBytelen(
+  const char *p,
+  int nByte,
+  int nChar
+);
+
+/*
+** Open a new iterator to iterate though all rowids that match the
+** specified token or token prefix.
+*/
+static int sqlite3Fts5IndexQuery(
+  Fts5Index *p,                   /* FTS index to query */
+  const char *pToken, int nToken, /* Token (or prefix) to query for */
+  int flags,                      /* Mask of FTS5INDEX_QUERY_X flags */
+  Fts5Colset *pColset,            /* Match these columns only */
+  Fts5IndexIter **ppIter          /* OUT: New iterator object */
+);
+
+/*
+** The various operations on open token or token prefix iterators opened
+** using sqlite3Fts5IndexQuery().
+*/
+static int sqlite3Fts5IterNext(Fts5IndexIter*);
+static int sqlite3Fts5IterNextFrom(Fts5IndexIter*, i64 iMatch);
+
+/*
+** Close an iterator opened by sqlite3Fts5IndexQuery().
+*/
+static void sqlite3Fts5IterClose(Fts5IndexIter*);
+
+/*
+** Close the reader blob handle, if it is open.
+*/
+static void sqlite3Fts5IndexCloseReader(Fts5Index*);
+
+/*
+** This interface is used by the fts5vocab module.
+*/
+static const char *sqlite3Fts5IterTerm(Fts5IndexIter*, int*);
+static int sqlite3Fts5IterNextScan(Fts5IndexIter*);
+static void *sqlite3Fts5StructureRef(Fts5Index*);
+static void sqlite3Fts5StructureRelease(void*);
+static int sqlite3Fts5StructureTest(Fts5Index*, void*);
+
+/*
+** Used by xInstToken():
+*/
+static int sqlite3Fts5IterToken(
+  Fts5IndexIter *pIndexIter,
+  const char *pToken, int nToken,
+  i64 iRowid,
+  int iCol,
+  int iOff,
+  const char **ppOut, int *pnOut
+);
+
+/*
+** Insert or remove data to or from the index. Each time a document is
+** added to or removed from the index, this function is called one or more
+** times.
+**
+** For an insert, it must be called once for each token in the new document.
+** If the operation is a delete, it must be called (at least) once for each
+** unique token in the document with an iCol value less than zero. The iPos
+** argument is ignored for a delete.
+*/
+static int sqlite3Fts5IndexWrite(
+  Fts5Index *p,                   /* Index to write to */
+  int iCol,                       /* Column token appears in (-ve -> delete) */
+  int iPos,                       /* Position of token within column */
+  const char *pToken, int nToken  /* Token to add or remove to or from index */
+);
+
+/*
+** Indicate that subsequent calls to sqlite3Fts5IndexWrite() pertain to
+** document iDocid.
+*/
+static int sqlite3Fts5IndexBeginWrite(
+  Fts5Index *p,                   /* Index to write to */
+  int bDelete,                    /* True if current operation is a delete */
+  i64 iDocid                      /* Docid to add or remove data from */
+);
+
+/*
+** Flush any data stored in the in-memory hash tables to the database.
+** Also close any open blob handles.
+*/
+static int sqlite3Fts5IndexSync(Fts5Index *p);
+
+/*
+** Discard any data stored in the in-memory hash tables. Do not write it
+** to the database. Additionally, assume that the contents of the %_data
+** table may have changed on disk. So any in-memory caches of %_data
+** records must be invalidated.
+*/
+static int sqlite3Fts5IndexRollback(Fts5Index *p);
+
+/*
+** Get or set the "averages" values.
+*/
+static int sqlite3Fts5IndexGetAverages(Fts5Index *p, i64 *pnRow, i64 *anSize);
+static int sqlite3Fts5IndexSetAverages(Fts5Index *p, const u8*, int);
+
+/*
+** Functions called by the storage module as part of integrity-check.
+*/
+static int sqlite3Fts5IndexIntegrityCheck(Fts5Index*, u64 cksum, int bUseCksum);
+
+/*
+** Called during virtual module initialization to register UDF
+** fts5_decode() with SQLite
+*/
+static int sqlite3Fts5IndexInit(sqlite3*);
+
+static int sqlite3Fts5IndexSetCookie(Fts5Index*, int);
+
+/*
+** Return the total number of entries read from the %_data table by
+** this connection since it was created.
+*/
+static int sqlite3Fts5IndexReads(Fts5Index *p);
+
+static int sqlite3Fts5IndexReinit(Fts5Index *p);
+static int sqlite3Fts5IndexOptimize(Fts5Index *p);
+static int sqlite3Fts5IndexMerge(Fts5Index *p, int nMerge);
+static int sqlite3Fts5IndexReset(Fts5Index *p);
+
+static int sqlite3Fts5IndexLoadConfig(Fts5Index *p);
+
+static int sqlite3Fts5IndexGetOrigin(Fts5Index *p, i64 *piOrigin);
+static int sqlite3Fts5IndexContentlessDelete(Fts5Index *p, i64 iOrigin, i64 iRowid);
+
+static void sqlite3Fts5IndexIterClearTokendata(Fts5IndexIter*);
+
+/* Used to populate hash tables for xInstToken in detail=none/column mode. */
+static int sqlite3Fts5IndexIterWriteTokendata(
+    Fts5IndexIter*, const char*, int, i64 iRowid, int iCol, int iOff
+);
+
+/*
+** End of interface to code in fts5_index.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_varint.c.
+*/
+static int sqlite3Fts5GetVarint32(const unsigned char *p, u32 *v);
+static int sqlite3Fts5GetVarintLen(u32 iVal);
+static u8 sqlite3Fts5GetVarint(const unsigned char*, u64*);
+static int sqlite3Fts5PutVarint(unsigned char *p, u64 v);
+
+#define fts5GetVarint32(a,b) sqlite3Fts5GetVarint32(a,(u32*)&(b))
+#define fts5GetVarint    sqlite3Fts5GetVarint
+
+#define fts5FastGetVarint32(a, iOff, nVal) {      \
+  nVal = (a)[iOff++];                             \
+  if( nVal & 0x80 ){                              \
+    iOff--;                                       \
+    iOff += fts5GetVarint32(&(a)[iOff], nVal);    \
+  }                                               \
+}
+
+
+/*
+** End of interface to code in fts5_varint.c.
+**************************************************************************/
+
+
+/**************************************************************************
+** Interface to code in fts5_main.c.
+*/
+
+/*
+** Virtual-table object.
+*/
+typedef struct Fts5Table Fts5Table;
+struct Fts5Table {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  Fts5Config *pConfig;            /* Virtual table configuration */
+  Fts5Index *pIndex;              /* Full-text index */
+};
+
+static int sqlite3Fts5LoadTokenizer(Fts5Config *pConfig);
+
+static Fts5Table *sqlite3Fts5TableFromCsrid(Fts5Global*, i64);
+
+static int sqlite3Fts5FlushToDisk(Fts5Table*);
+
+static void sqlite3Fts5ClearLocale(Fts5Config *pConfig);
+static void sqlite3Fts5SetLocale(Fts5Config *pConfig, const char *pLoc, int nLoc);
+
+static int sqlite3Fts5IsLocaleValue(Fts5Config *pConfig, sqlite3_value *pVal);
+static int sqlite3Fts5DecodeLocaleValue(sqlite3_value *pVal,
+    const char **ppText, int *pnText, const char **ppLoc, int *pnLoc
+);
+
+/*
+** End of interface to code in fts5.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_hash.c.
+*/
+typedef struct Fts5Hash Fts5Hash;
+
+/*
+** Create a hash table, free a hash table.
+*/
+static int sqlite3Fts5HashNew(Fts5Config*, Fts5Hash**, int *pnSize);
+static void sqlite3Fts5HashFree(Fts5Hash*);
+
+static int sqlite3Fts5HashWrite(
+  Fts5Hash*,
+  i64 iRowid,                     /* Rowid for this entry */
+  int iCol,                       /* Column token appears in (-ve -> delete) */
+  int iPos,                       /* Position of token within column */
+  char bByte,
+  const char *pToken, int nToken  /* Token to add or remove to or from index */
+);
+
+/*
+** Empty (but do not delete) a hash table.
+*/
+static void sqlite3Fts5HashClear(Fts5Hash*);
+
+/*
+** Return true if the hash is empty, false otherwise.
+*/
+static int sqlite3Fts5HashIsEmpty(Fts5Hash*);
+
+static int sqlite3Fts5HashQuery(
+  Fts5Hash*,                      /* Hash table to query */
+  int nPre,
+  const char *pTerm, int nTerm,   /* Query term */
+  void **ppObj,                   /* OUT: Pointer to doclist for pTerm */
+  int *pnDoclist                  /* OUT: Size of doclist in bytes */
+);
+
+static int sqlite3Fts5HashScanInit(
+  Fts5Hash*,                      /* Hash table to query */
+  const char *pTerm, int nTerm    /* Query prefix */
+);
+static void sqlite3Fts5HashScanNext(Fts5Hash*);
+static int sqlite3Fts5HashScanEof(Fts5Hash*);
+static void sqlite3Fts5HashScanEntry(Fts5Hash *,
+  const char **pzTerm,            /* OUT: term (nul-terminated) */
+  int *pnTerm,                    /* OUT: Size of term in bytes */
+  const u8 **ppDoclist,           /* OUT: pointer to doclist */
+  int *pnDoclist                  /* OUT: size of doclist in bytes */
+);
+
+
+
+/*
+** End of interface to code in fts5_hash.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_storage.c. fts5_storage.c contains contains
+** code to access the data stored in the %_content and %_docsize tables.
+*/
+
+#define FTS5_STMT_SCAN_ASC  0     /* SELECT rowid, * FROM ... ORDER BY 1 ASC */
+#define FTS5_STMT_SCAN_DESC 1     /* SELECT rowid, * FROM ... ORDER BY 1 DESC */
+#define FTS5_STMT_LOOKUP    2     /* SELECT rowid, * FROM ... WHERE rowid=? */
+
+typedef struct Fts5Storage Fts5Storage;
+
+static int sqlite3Fts5StorageOpen(Fts5Config*, Fts5Index*, int, Fts5Storage**, char**);
+static int sqlite3Fts5StorageClose(Fts5Storage *p);
+static int sqlite3Fts5StorageRename(Fts5Storage*, const char *zName);
+
+static int sqlite3Fts5DropAll(Fts5Config*);
+static int sqlite3Fts5CreateTable(Fts5Config*, const char*, const char*, int, char **);
+
+static int sqlite3Fts5StorageDelete(Fts5Storage *p, i64, sqlite3_value**, int);
+static int sqlite3Fts5StorageContentInsert(Fts5Storage *p, int, sqlite3_value**, i64*);
+static int sqlite3Fts5StorageIndexInsert(Fts5Storage *p, sqlite3_value**, i64);
+
+static int sqlite3Fts5StorageIntegrity(Fts5Storage *p, int iArg);
+
+static int sqlite3Fts5StorageStmt(Fts5Storage *p, int eStmt, sqlite3_stmt**, char**);
+static void sqlite3Fts5StorageStmtRelease(Fts5Storage *p, int eStmt, sqlite3_stmt*);
+
+static int sqlite3Fts5StorageDocsize(Fts5Storage *p, i64 iRowid, int *aCol);
+static int sqlite3Fts5StorageSize(Fts5Storage *p, int iCol, i64 *pnAvg);
+static int sqlite3Fts5StorageRowCount(Fts5Storage *p, i64 *pnRow);
+
+static int sqlite3Fts5StorageSync(Fts5Storage *p);
+static int sqlite3Fts5StorageRollback(Fts5Storage *p);
+
+static int sqlite3Fts5StorageConfigValue(
+    Fts5Storage *p, const char*, sqlite3_value*, int
+);
+
+static int sqlite3Fts5StorageDeleteAll(Fts5Storage *p);
+static int sqlite3Fts5StorageRebuild(Fts5Storage *p);
+static int sqlite3Fts5StorageOptimize(Fts5Storage *p);
+static int sqlite3Fts5StorageMerge(Fts5Storage *p, int nMerge);
+static int sqlite3Fts5StorageReset(Fts5Storage *p);
+
+static void sqlite3Fts5StorageReleaseDeleteRow(Fts5Storage*);
+static int sqlite3Fts5StorageFindDeleteRow(Fts5Storage *p, i64 iDel);
+
+/*
+** End of interface to code in fts5_storage.c.
+**************************************************************************/
+
+
+/**************************************************************************
+** Interface to code in fts5_expr.c.
+*/
+typedef struct Fts5Expr Fts5Expr;
+typedef struct Fts5ExprNode Fts5ExprNode;
+typedef struct Fts5Parse Fts5Parse;
+typedef struct Fts5Token Fts5Token;
+typedef struct Fts5ExprPhrase Fts5ExprPhrase;
+typedef struct Fts5ExprNearset Fts5ExprNearset;
+
+struct Fts5Token {
+  const char *p;                  /* Token text (not NULL terminated) */
+  int n;                          /* Size of buffer p in bytes */
+};
+
+/* Parse a MATCH expression. */
+static int sqlite3Fts5ExprNew(
+  Fts5Config *pConfig,
+  int bPhraseToAnd,
+  int iCol,                       /* Column on LHS of MATCH operator */
+  const char *zExpr,
+  Fts5Expr **ppNew,
+  char **pzErr
+);
+static int sqlite3Fts5ExprPattern(
+  Fts5Config *pConfig,
+  int bGlob,
+  int iCol,
+  const char *zText,
+  Fts5Expr **pp
+);
+
+/*
+** for(rc = sqlite3Fts5ExprFirst(pExpr, pIdx, bDesc);
+**     rc==SQLITE_OK && 0==sqlite3Fts5ExprEof(pExpr);
+**     rc = sqlite3Fts5ExprNext(pExpr)
+** ){
+**   // The document with rowid iRowid matches the expression!
+**   i64 iRowid = sqlite3Fts5ExprRowid(pExpr);
+** }
+*/
+static int sqlite3Fts5ExprFirst(Fts5Expr*, Fts5Index *pIdx, i64 iMin, int bDesc);
+static int sqlite3Fts5ExprNext(Fts5Expr*, i64 iMax);
+static int sqlite3Fts5ExprEof(Fts5Expr*);
+static i64 sqlite3Fts5ExprRowid(Fts5Expr*);
+
+static void sqlite3Fts5ExprFree(Fts5Expr*);
+static int sqlite3Fts5ExprAnd(Fts5Expr **pp1, Fts5Expr *p2);
+
+/* Called during startup to register a UDF with SQLite */
+static int sqlite3Fts5ExprInit(Fts5Global*, sqlite3*);
+
+static int sqlite3Fts5ExprPhraseCount(Fts5Expr*);
+static int sqlite3Fts5ExprPhraseSize(Fts5Expr*, int iPhrase);
+static int sqlite3Fts5ExprPoslist(Fts5Expr*, int, const u8 **);
+
+typedef struct Fts5PoslistPopulator Fts5PoslistPopulator;
+static Fts5PoslistPopulator *sqlite3Fts5ExprClearPoslists(Fts5Expr*, int);
+static int sqlite3Fts5ExprPopulatePoslists(
+    Fts5Config*, Fts5Expr*, Fts5PoslistPopulator*, int, const char*, int
+);
+static void sqlite3Fts5ExprCheckPoslists(Fts5Expr*, i64);
+
+static int sqlite3Fts5ExprClonePhrase(Fts5Expr*, int, Fts5Expr**);
+
+static int sqlite3Fts5ExprPhraseCollist(Fts5Expr *, int, const u8 **, int *);
+
+static int sqlite3Fts5ExprQueryToken(Fts5Expr*, int, int, const char**, int*);
+static int sqlite3Fts5ExprInstToken(Fts5Expr*, i64, int, int, int, int, const char**, int*);
+static void sqlite3Fts5ExprClearTokens(Fts5Expr*);
+
+/*******************************************
+** The fts5_expr.c API above this point is used by the other hand-written
+** C code in this module. The interfaces below this point are called by
+** the parser code in fts5parse.y.  */
+
+static void sqlite3Fts5ParseError(Fts5Parse *pParse, const char *zFmt, ...);
+
+static Fts5ExprNode *sqlite3Fts5ParseNode(
+  Fts5Parse *pParse,
+  int eType,
+  Fts5ExprNode *pLeft,
+  Fts5ExprNode *pRight,
+  Fts5ExprNearset *pNear
+);
+
+static Fts5ExprNode *sqlite3Fts5ParseImplicitAnd(
+  Fts5Parse *pParse,
+  Fts5ExprNode *pLeft,
+  Fts5ExprNode *pRight
+);
+
+static Fts5ExprPhrase *sqlite3Fts5ParseTerm(
+  Fts5Parse *pParse,
+  Fts5ExprPhrase *pPhrase,
+  Fts5Token *pToken,
+  int bPrefix
+);
+
+static void sqlite3Fts5ParseSetCaret(Fts5ExprPhrase*);
+
+static Fts5ExprNearset *sqlite3Fts5ParseNearset(
+  Fts5Parse*,
+  Fts5ExprNearset*,
+  Fts5ExprPhrase*
+);
+
+static Fts5Colset *sqlite3Fts5ParseColset(
+  Fts5Parse*,
+  Fts5Colset*,
+  Fts5Token *
+);
+
+static void sqlite3Fts5ParsePhraseFree(Fts5ExprPhrase*);
+static void sqlite3Fts5ParseNearsetFree(Fts5ExprNearset*);
+static void sqlite3Fts5ParseNodeFree(Fts5ExprNode*);
+
+static void sqlite3Fts5ParseSetDistance(Fts5Parse*, Fts5ExprNearset*, Fts5Token*);
+static void sqlite3Fts5ParseSetColset(Fts5Parse*, Fts5ExprNode*, Fts5Colset*);
+static Fts5Colset *sqlite3Fts5ParseColsetInvert(Fts5Parse*, Fts5Colset*);
+static void sqlite3Fts5ParseFinished(Fts5Parse *pParse, Fts5ExprNode *p);
+static void sqlite3Fts5ParseNear(Fts5Parse *pParse, Fts5Token*);
+
+/*
+** End of interface to code in fts5_expr.c.
+**************************************************************************/
+
+
+
+/**************************************************************************
+** Interface to code in fts5_aux.c.
+*/
+
+static int sqlite3Fts5AuxInit(fts5_api*);
+/*
+** End of interface to code in fts5_aux.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_tokenizer.c.
+*/
+
+static int sqlite3Fts5TokenizerInit(fts5_api*);
+static int sqlite3Fts5TokenizerPattern(
+    int (*xCreate)(void*, const char**, int, Fts5Tokenizer**),
+    Fts5Tokenizer *pTok
+);
+static int sqlite3Fts5TokenizerPreload(Fts5TokenizerConfig*);
+/*
+** End of interface to code in fts5_tokenizer.c.
+**************************************************************************/
+
+/**************************************************************************
+** Interface to code in fts5_vocab.c.
+*/
+
+static int sqlite3Fts5VocabInit(Fts5Global*, sqlite3*);
+
+/*
+** End of interface to code in fts5_vocab.c.
+**************************************************************************/
+
+
+/**************************************************************************
+** Interface to automatically generated code in fts5_unicode2.c.
+*/
+static int sqlite3Fts5UnicodeIsdiacritic(int c);
+static int sqlite3Fts5UnicodeFold(int c, int bRemoveDiacritic);
+
+static int sqlite3Fts5UnicodeCatParse(const char*, u8*);
+static int sqlite3Fts5UnicodeCategory(u32 iCode);
+static void sqlite3Fts5UnicodeAscii(u8*, u8*);
+/*
+** End of interface to code in fts5_unicode2.c.
+**************************************************************************/
+
+#endif
+
+#define FTS5_OR                               1
+#define FTS5_AND                              2
+#define FTS5_NOT                              3
+#define FTS5_TERM                             4
+#define FTS5_COLON                            5
+#define FTS5_MINUS                            6
+#define FTS5_LCP                              7
+#define FTS5_RCP                              8
+#define FTS5_STRING                           9
+#define FTS5_LP                              10
+#define FTS5_RP                              11
+#define FTS5_CARET                           12
+#define FTS5_COMMA                           13
+#define FTS5_PLUS                            14
+#define FTS5_STAR                            15
+
+/* This file is automatically generated by Lemon from input grammar
+** source file "fts5parse.y".
+*/
+/*
+** 2000-05-29
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** Driver template for the LEMON parser generator.
+**
+** The "lemon" program processes an LALR(1) input grammar file, then uses
+** this template to construct a parser.  The "lemon" program inserts text
+** at each "%%" line.  Also, any "P-a-r-s-e" identifer prefix (without the
+** interstitial "-" characters) contained in this template is changed into
+** the value of the %name directive from the grammar.  Otherwise, the content
+** of this template is copied straight through into the generate parser
+** source file.
+**
+** The following is the concatenation of all %include directives from the
+** input grammar file:
+*/
+/************ Begin %include sections from the grammar ************************/
+
+/* #include "fts5Int.h" */
+/* #include "fts5parse.h" */
+
+/*
+** Disable all error recovery processing in the parser push-down
+** automaton.
+*/
+#define fts5YYNOERRORRECOVERY 1
+
+/*
+** Make fts5yytestcase() the same as testcase()
+*/
+#define fts5yytestcase(X) testcase(X)
+
+/*
+** Indicate that sqlite3ParserFree() will never be called with a null
+** pointer.
+*/
+#define fts5YYPARSEFREENOTNULL 1
+
+/*
+** Alternative datatype for the argument to the malloc() routine passed
+** into sqlite3ParserAlloc().  The default is size_t.
+*/
+#define fts5YYMALLOCARGTYPE  u64
+
+/**************** End of %include directives **********************************/
+/* These constants specify the various numeric values for terminal symbols.
+***************** Begin token definitions *************************************/
+#ifndef FTS5_OR
+#define FTS5_OR                              1
+#define FTS5_AND                             2
+#define FTS5_NOT                             3
+#define FTS5_TERM                            4
+#define FTS5_COLON                           5
+#define FTS5_MINUS                           6
+#define FTS5_LCP                             7
+#define FTS5_RCP                             8
+#define FTS5_STRING                          9
+#define FTS5_LP                             10
+#define FTS5_RP                             11
+#define FTS5_CARET                          12
+#define FTS5_COMMA                          13
+#define FTS5_PLUS                           14
+#define FTS5_STAR                           15
+#endif
+/**************** End token definitions ***************************************/
+
+/* The next sections is a series of control #defines.
+** various aspects of the generated parser.
+**    fts5YYCODETYPE         is the data type used to store the integer codes
+**                       that represent terminal and non-terminal symbols.
+**                       "unsigned char" is used if there are fewer than
+**                       256 symbols.  Larger types otherwise.
+**    fts5YYNOCODE           is a number of type fts5YYCODETYPE that is not used for
+**                       any terminal or nonterminal symbol.
+**    fts5YYFALLBACK         If defined, this indicates that one or more tokens
+**                       (also known as: "terminal symbols") have fall-back
+**                       values which should be used if the original symbol
+**                       would not parse.  This permits keywords to sometimes
+**                       be used as identifiers, for example.
+**    fts5YYACTIONTYPE       is the data type used for "action codes" - numbers
+**                       that indicate what to do in response to the next
+**                       token.
+**    sqlite3Fts5ParserFTS5TOKENTYPE     is the data type used for minor type for terminal
+**                       symbols.  Background: A "minor type" is a semantic
+**                       value associated with a terminal or non-terminal
+**                       symbols.  For example, for an "ID" terminal symbol,
+**                       the minor type might be the name of the identifier.
+**                       Each non-terminal can have a different minor type.
+**                       Terminal symbols all have the same minor type, though.
+**                       This macros defines the minor type for terminal
+**                       symbols.
+**    fts5YYMINORTYPE        is the data type used for all minor types.
+**                       This is typically a union of many types, one of
+**                       which is sqlite3Fts5ParserFTS5TOKENTYPE.  The entry in the union
+**                       for terminal symbols is called "fts5yy0".
+**    fts5YYSTACKDEPTH       is the maximum depth of the parser's stack.  If
+**                       zero the stack is dynamically sized using realloc()
+**    sqlite3Fts5ParserARG_SDECL     A static variable declaration for the %extra_argument
+**    sqlite3Fts5ParserARG_PDECL     A parameter declaration for the %extra_argument
+**    sqlite3Fts5ParserARG_PARAM     Code to pass %extra_argument as a subroutine parameter
+**    sqlite3Fts5ParserARG_STORE     Code to store %extra_argument into fts5yypParser
+**    sqlite3Fts5ParserARG_FETCH     Code to extract %extra_argument from fts5yypParser
+**    sqlite3Fts5ParserCTX_*         As sqlite3Fts5ParserARG_ except for %extra_context
+**    fts5YYREALLOC          Name of the realloc() function to use
+**    fts5YYFREE             Name of the free() function to use
+**    fts5YYDYNSTACK         True if stack space should be extended on heap
+**    fts5YYERRORSYMBOL      is the code number of the error symbol.  If not
+**                       defined, then do no error processing.
+**    fts5YYNSTATE           the combined number of states.
+**    fts5YYNRULE            the number of rules in the grammar
+**    fts5YYNFTS5TOKEN           Number of terminal symbols
+**    fts5YY_MAX_SHIFT       Maximum value for shift actions
+**    fts5YY_MIN_SHIFTREDUCE Minimum value for shift-reduce actions
+**    fts5YY_MAX_SHIFTREDUCE Maximum value for shift-reduce actions
+**    fts5YY_ERROR_ACTION    The fts5yy_action[] code for syntax error
+**    fts5YY_ACCEPT_ACTION   The fts5yy_action[] code for accept
+**    fts5YY_NO_ACTION       The fts5yy_action[] code for no-op
+**    fts5YY_MIN_REDUCE      Minimum value for reduce actions
+**    fts5YY_MAX_REDUCE      Maximum value for reduce actions
+**    fts5YY_MIN_DSTRCTR     Minimum symbol value that has a destructor
+**    fts5YY_MAX_DSTRCTR     Maximum symbol value that has a destructor
+*/
+#ifndef INTERFACE
+# define INTERFACE 1
+#endif
+/************* Begin control #defines *****************************************/
+#define fts5YYCODETYPE unsigned char
+#define fts5YYNOCODE 27
+#define fts5YYACTIONTYPE unsigned char
+#define sqlite3Fts5ParserFTS5TOKENTYPE Fts5Token
+typedef union {
+  int fts5yyinit;
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yy0;
+  int fts5yy4;
+  Fts5Colset* fts5yy11;
+  Fts5ExprNode* fts5yy24;
+  Fts5ExprNearset* fts5yy46;
+  Fts5ExprPhrase* fts5yy53;
+} fts5YYMINORTYPE;
+#ifndef fts5YYSTACKDEPTH
+#define fts5YYSTACKDEPTH 100
+#endif
+#define sqlite3Fts5ParserARG_SDECL Fts5Parse *pParse;
+#define sqlite3Fts5ParserARG_PDECL ,Fts5Parse *pParse
+#define sqlite3Fts5ParserARG_PARAM ,pParse
+#define sqlite3Fts5ParserARG_FETCH Fts5Parse *pParse=fts5yypParser->pParse;
+#define sqlite3Fts5ParserARG_STORE fts5yypParser->pParse=pParse;
+#define fts5YYREALLOC realloc
+#define fts5YYFREE free
+#define fts5YYDYNSTACK 0
+#define sqlite3Fts5ParserCTX_SDECL
+#define sqlite3Fts5ParserCTX_PDECL
+#define sqlite3Fts5ParserCTX_PARAM
+#define sqlite3Fts5ParserCTX_FETCH
+#define sqlite3Fts5ParserCTX_STORE
+#define fts5YYNSTATE             35
+#define fts5YYNRULE              28
+#define fts5YYNRULE_WITH_ACTION  28
+#define fts5YYNFTS5TOKEN             16
+#define fts5YY_MAX_SHIFT         34
+#define fts5YY_MIN_SHIFTREDUCE   52
+#define fts5YY_MAX_SHIFTREDUCE   79
+#define fts5YY_ERROR_ACTION      80
+#define fts5YY_ACCEPT_ACTION     81
+#define fts5YY_NO_ACTION         82
+#define fts5YY_MIN_REDUCE        83
+#define fts5YY_MAX_REDUCE        110
+#define fts5YY_MIN_DSTRCTR       16
+#define fts5YY_MAX_DSTRCTR       24
+/************* End control #defines *******************************************/
+#define fts5YY_NLOOKAHEAD ((int)(sizeof(fts5yy_lookahead)/sizeof(fts5yy_lookahead[0])))
+
+/* Define the fts5yytestcase() macro to be a no-op if is not already defined
+** otherwise.
+**
+** Applications can choose to define fts5yytestcase() in the %include section
+** to a macro that can assist in verifying code coverage.  For production
+** code the fts5yytestcase() macro should be turned off.  But it is useful
+** for testing.
+*/
+#ifndef fts5yytestcase
+# define fts5yytestcase(X)
+#endif
+
+/* Macro to determine if stack space has the ability to grow using
+** heap memory.
+*/
+#if fts5YYSTACKDEPTH<=0 || fts5YYDYNSTACK
+# define fts5YYGROWABLESTACK 1
+#else
+# define fts5YYGROWABLESTACK 0
+#endif
+
+/* Guarantee a minimum number of initial stack slots.
+*/
+#if fts5YYSTACKDEPTH<=0
+# undef fts5YYSTACKDEPTH
+# define fts5YYSTACKDEPTH 2  /* Need a minimum stack size */
+#endif
+
+
+/* Next are the tables used to determine what action to take based on the
+** current state and lookahead token.  These tables are used to implement
+** functions that take a state number and lookahead value and return an
+** action integer.
+**
+** Suppose the action integer is N.  Then the action is determined as
+** follows
+**
+**   0 <= N <= fts5YY_MAX_SHIFT             Shift N.  That is, push the lookahead
+**                                      token onto the stack and goto state N.
+**
+**   N between fts5YY_MIN_SHIFTREDUCE       Shift to an arbitrary state then
+**     and fts5YY_MAX_SHIFTREDUCE           reduce by rule N-fts5YY_MIN_SHIFTREDUCE.
+**
+**   N == fts5YY_ERROR_ACTION               A syntax error has occurred.
+**
+**   N == fts5YY_ACCEPT_ACTION              The parser accepts its input.
+**
+**   N == fts5YY_NO_ACTION                  No such action.  Denotes unused
+**                                      slots in the fts5yy_action[] table.
+**
+**   N between fts5YY_MIN_REDUCE            Reduce by rule N-fts5YY_MIN_REDUCE
+**     and fts5YY_MAX_REDUCE
+**
+** The action table is constructed as a single large table named fts5yy_action[].
+** Given state S and lookahead X, the action is computed as either:
+**
+**    (A)   N = fts5yy_action[ fts5yy_shift_ofst[S] + X ]
+**    (B)   N = fts5yy_default[S]
+**
+** The (A) formula is preferred.  The B formula is used instead if
+** fts5yy_lookahead[fts5yy_shift_ofst[S]+X] is not equal to X.
+**
+** The formulas above are for computing the action when the lookahead is
+** a terminal symbol.  If the lookahead is a non-terminal (as occurs after
+** a reduce action) then the fts5yy_reduce_ofst[] array is used in place of
+** the fts5yy_shift_ofst[] array.
+**
+** The following are the tables generated in this section:
+**
+**  fts5yy_action[]        A single table containing all actions.
+**  fts5yy_lookahead[]     A table containing the lookahead for each entry in
+**                     fts5yy_action.  Used to detect hash collisions.
+**  fts5yy_shift_ofst[]    For each state, the offset into fts5yy_action for
+**                     shifting terminals.
+**  fts5yy_reduce_ofst[]   For each state, the offset into fts5yy_action for
+**                     shifting non-terminals after a reduce.
+**  fts5yy_default[]       Default action for each state.
+**
+*********** Begin parsing tables **********************************************/
+#define fts5YY_ACTTAB_COUNT (105)
+static const fts5YYACTIONTYPE fts5yy_action[] = {
+ /*     0 */    81,   20,   96,    6,   28,   99,   98,   26,   26,   18,
+ /*    10 */    96,    6,   28,   17,   98,   56,   26,   19,   96,    6,
+ /*    20 */    28,   14,   98,   14,   26,   31,   92,   96,    6,   28,
+ /*    30 */   108,   98,   25,   26,   21,   96,    6,   28,   78,   98,
+ /*    40 */    58,   26,   29,   96,    6,   28,  107,   98,   22,   26,
+ /*    50 */    24,   16,   12,   11,    1,   13,   13,   24,   16,   23,
+ /*    60 */    11,   33,   34,   13,   97,    8,   27,   32,   98,    7,
+ /*    70 */    26,    3,    4,    5,    3,    4,    5,    3,   83,    4,
+ /*    80 */     5,    3,   63,    5,    3,   62,   12,    2,   86,   13,
+ /*    90 */     9,   30,   10,   10,   54,   57,   75,   78,   78,   53,
+ /*   100 */    57,   15,   82,   82,   71,
+};
+static const fts5YYCODETYPE fts5yy_lookahead[] = {
+ /*     0 */    16,   17,   18,   19,   20,   22,   22,   24,   24,   17,
+ /*    10 */    18,   19,   20,    7,   22,    9,   24,   17,   18,   19,
+ /*    20 */    20,    9,   22,    9,   24,   13,   17,   18,   19,   20,
+ /*    30 */    26,   22,   24,   24,   17,   18,   19,   20,   15,   22,
+ /*    40 */     9,   24,   17,   18,   19,   20,   26,   22,   21,   24,
+ /*    50 */     6,    7,    9,    9,   10,   12,   12,    6,    7,   21,
+ /*    60 */     9,   24,   25,   12,   18,    5,   20,   14,   22,    5,
+ /*    70 */    24,    3,    1,    2,    3,    1,    2,    3,    0,    1,
+ /*    80 */     2,    3,   11,    2,    3,   11,    9,   10,    5,   12,
+ /*    90 */    23,   24,   10,   10,    8,    9,    9,   15,   15,    8,
+ /*   100 */     9,    9,   27,   27,   11,   27,   27,   27,   27,   27,
+ /*   110 */    27,   27,   27,   27,   27,   27,   27,   27,   27,   27,
+ /*   120 */    27,
+};
+#define fts5YY_SHIFT_COUNT    (34)
+#define fts5YY_SHIFT_MIN      (0)
+#define fts5YY_SHIFT_MAX      (93)
+static const unsigned char fts5yy_shift_ofst[] = {
+ /*     0 */    44,   44,   44,   44,   44,   44,   51,   77,   43,   12,
+ /*    10 */    14,   83,   82,   14,   23,   23,   31,   31,   71,   74,
+ /*    20 */    78,   81,   86,   91,    6,   53,   53,   60,   64,   68,
+ /*    30 */    53,   87,   92,   53,   93,
+};
+#define fts5YY_REDUCE_COUNT (17)
+#define fts5YY_REDUCE_MIN   (-17)
+#define fts5YY_REDUCE_MAX   (67)
+static const signed char fts5yy_reduce_ofst[] = {
+ /*     0 */   -16,   -8,    0,    9,   17,   25,   46,  -17,  -17,   37,
+ /*    10 */    67,    4,    4,    8,    4,   20,   27,   38,
+};
+static const fts5YYACTIONTYPE fts5yy_default[] = {
+ /*     0 */    80,   80,   80,   80,   80,   80,   95,   80,   80,  105,
+ /*    10 */    80,  110,  110,   80,  110,  110,   80,   80,   80,   80,
+ /*    20 */    80,   91,   80,   80,   80,  101,  100,   80,   80,   90,
+ /*    30 */   103,   80,   80,  104,   80,
+};
+/********** End of lemon-generated parsing tables *****************************/
+
+/* The next table maps tokens (terminal symbols) into fallback tokens.
+** If a construct like the following:
+**
+**      %fallback ID X Y Z.
+**
+** appears in the grammar, then ID becomes a fallback token for X, Y,
+** and Z.  Whenever one of the tokens X, Y, or Z is input to the parser
+** but it does not parse, the type of the token is changed to ID and
+** the parse is retried before an error is thrown.
+**
+** This feature can be used, for example, to cause some keywords in a language
+** to revert to identifiers if they keyword does not apply in the context where
+** it appears.
+*/
+#ifdef fts5YYFALLBACK
+static const fts5YYCODETYPE fts5yyFallback[] = {
+};
+#endif /* fts5YYFALLBACK */
+
+/* The following structure represents a single element of the
+** parser's stack.  Information stored includes:
+**
+**   +  The state number for the parser at this level of the stack.
+**
+**   +  The value of the token stored at this level of the stack.
+**      (In other words, the "major" token.)
+**
+**   +  The semantic value stored at this level of the stack.  This is
+**      the information used by the action routines in the grammar.
+**      It is sometimes called the "minor" token.
+**
+** After the "shift" half of a SHIFTREDUCE action, the stateno field
+** actually contains the reduce action for the second half of the
+** SHIFTREDUCE.
+*/
+struct fts5yyStackEntry {
+  fts5YYACTIONTYPE stateno;  /* The state-number, or reduce action in SHIFTREDUCE */
+  fts5YYCODETYPE major;      /* The major token value.  This is the code
+                         ** number for the token at this stack level */
+  fts5YYMINORTYPE minor;     /* The user-supplied minor token value.  This
+                         ** is the value of the token  */
+};
+typedef struct fts5yyStackEntry fts5yyStackEntry;
+
+/* The state of the parser is completely contained in an instance of
+** the following structure */
+struct fts5yyParser {
+  fts5yyStackEntry *fts5yytos;          /* Pointer to top element of the stack */
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+  int fts5yyhwm;                    /* High-water mark of the stack */
+#endif
+#ifndef fts5YYNOERRORRECOVERY
+  int fts5yyerrcnt;                 /* Shifts left before out of the error */
+#endif
+  sqlite3Fts5ParserARG_SDECL                /* A place to hold %extra_argument */
+  sqlite3Fts5ParserCTX_SDECL                /* A place to hold %extra_context */
+  fts5yyStackEntry *fts5yystackEnd;           /* Last entry in the stack */
+  fts5yyStackEntry *fts5yystack;              /* The parser stack */
+  fts5yyStackEntry fts5yystk0[fts5YYSTACKDEPTH];  /* Initial stack space */
+};
+typedef struct fts5yyParser fts5yyParser;
+
+/* #include <assert.h> */
+#ifndef NDEBUG
+/* #include <stdio.h> */
+static FILE *fts5yyTraceFILE = 0;
+static char *fts5yyTracePrompt = 0;
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/*
+** Turn parser tracing on by giving a stream to which to write the trace
+** and a prompt to preface each trace message.  Tracing is turned off
+** by making either argument NULL
+**
+** Inputs:
+** <ul>
+** <li> A FILE* to which trace output should be written.
+**      If NULL, then tracing is turned off.
+** <li> A prefix string written at the beginning of every
+**      line of trace output.  If NULL, then tracing is
+**      turned off.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+static void sqlite3Fts5ParserTrace(FILE *TraceFILE, char *zTracePrompt){
+  fts5yyTraceFILE = TraceFILE;
+  fts5yyTracePrompt = zTracePrompt;
+  if( fts5yyTraceFILE==0 ) fts5yyTracePrompt = 0;
+  else if( fts5yyTracePrompt==0 ) fts5yyTraceFILE = 0;
+}
+#endif /* NDEBUG */
+
+#if defined(fts5YYCOVERAGE) || !defined(NDEBUG)
+/* For tracing shifts, the names of all terminals and nonterminals
+** are required.  The following table supplies these names */
+static const char *const fts5yyTokenName[] = {
+  /*    0 */ "$",
+  /*    1 */ "OR",
+  /*    2 */ "AND",
+  /*    3 */ "NOT",
+  /*    4 */ "TERM",
+  /*    5 */ "COLON",
+  /*    6 */ "MINUS",
+  /*    7 */ "LCP",
+  /*    8 */ "RCP",
+  /*    9 */ "STRING",
+  /*   10 */ "LP",
+  /*   11 */ "RP",
+  /*   12 */ "CARET",
+  /*   13 */ "COMMA",
+  /*   14 */ "PLUS",
+  /*   15 */ "STAR",
+  /*   16 */ "input",
+  /*   17 */ "expr",
+  /*   18 */ "cnearset",
+  /*   19 */ "exprlist",
+  /*   20 */ "colset",
+  /*   21 */ "colsetlist",
+  /*   22 */ "nearset",
+  /*   23 */ "nearphrases",
+  /*   24 */ "phrase",
+  /*   25 */ "neardist_opt",
+  /*   26 */ "star_opt",
+};
+#endif /* defined(fts5YYCOVERAGE) || !defined(NDEBUG) */
+
+#ifndef NDEBUG
+/* For tracing reduce actions, the names of all rules are required.
+*/
+static const char *const fts5yyRuleName[] = {
+ /*   0 */ "input ::= expr",
+ /*   1 */ "colset ::= MINUS LCP colsetlist RCP",
+ /*   2 */ "colset ::= LCP colsetlist RCP",
+ /*   3 */ "colset ::= STRING",
+ /*   4 */ "colset ::= MINUS STRING",
+ /*   5 */ "colsetlist ::= colsetlist STRING",
+ /*   6 */ "colsetlist ::= STRING",
+ /*   7 */ "expr ::= expr AND expr",
+ /*   8 */ "expr ::= expr OR expr",
+ /*   9 */ "expr ::= expr NOT expr",
+ /*  10 */ "expr ::= colset COLON LP expr RP",
+ /*  11 */ "expr ::= LP expr RP",
+ /*  12 */ "expr ::= exprlist",
+ /*  13 */ "exprlist ::= cnearset",
+ /*  14 */ "exprlist ::= exprlist cnearset",
+ /*  15 */ "cnearset ::= nearset",
+ /*  16 */ "cnearset ::= colset COLON nearset",
+ /*  17 */ "nearset ::= phrase",
+ /*  18 */ "nearset ::= CARET phrase",
+ /*  19 */ "nearset ::= STRING LP nearphrases neardist_opt RP",
+ /*  20 */ "nearphrases ::= phrase",
+ /*  21 */ "nearphrases ::= nearphrases phrase",
+ /*  22 */ "neardist_opt ::=",
+ /*  23 */ "neardist_opt ::= COMMA STRING",
+ /*  24 */ "phrase ::= phrase PLUS STRING star_opt",
+ /*  25 */ "phrase ::= STRING star_opt",
+ /*  26 */ "star_opt ::= STAR",
+ /*  27 */ "star_opt ::=",
+};
+#endif /* NDEBUG */
+
+
+#if fts5YYGROWABLESTACK
+/*
+** Try to increase the size of the parser stack.  Return the number
+** of errors.  Return 0 on success.
+*/
+static int fts5yyGrowStack(fts5yyParser *p){
+  int oldSize = 1 + (int)(p->fts5yystackEnd - p->fts5yystack);
+  int newSize;
+  int idx;
+  fts5yyStackEntry *pNew;
+
+  newSize = oldSize*2 + 100;
+  idx = (int)(p->fts5yytos - p->fts5yystack);
+  if( p->fts5yystack==p->fts5yystk0 ){
+    pNew = fts5YYREALLOC(0, newSize*sizeof(pNew[0]));
+    if( pNew==0 ) return 1;
+    memcpy(pNew, p->fts5yystack, oldSize*sizeof(pNew[0]));
+  }else{
+    pNew = fts5YYREALLOC(p->fts5yystack, newSize*sizeof(pNew[0]));
+    if( pNew==0 ) return 1;
+  }
+  p->fts5yystack = pNew;
+  p->fts5yytos = &p->fts5yystack[idx];
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fprintf(fts5yyTraceFILE,"%sStack grows from %d to %d entries.\n",
+            fts5yyTracePrompt, oldSize, newSize);
+  }
+#endif
+  p->fts5yystackEnd = &p->fts5yystack[newSize-1];
+  return 0;
+}
+#endif /* fts5YYGROWABLESTACK */
+
+#if !fts5YYGROWABLESTACK
+/* For builds that do no have a growable stack, fts5yyGrowStack always
+** returns an error.
+*/
+# define fts5yyGrowStack(X) 1
+#endif
+
+/* Datatype of the argument to the memory allocated passed as the
+** second argument to sqlite3Fts5ParserAlloc() below.  This can be changed by
+** putting an appropriate #define in the %include section of the input
+** grammar.
+*/
+#ifndef fts5YYMALLOCARGTYPE
+# define fts5YYMALLOCARGTYPE size_t
+#endif
+
+/* Initialize a new parser that has already been allocated.
+*/
+static void sqlite3Fts5ParserInit(void *fts5yypRawParser sqlite3Fts5ParserCTX_PDECL){
+  fts5yyParser *fts5yypParser = (fts5yyParser*)fts5yypRawParser;
+  sqlite3Fts5ParserCTX_STORE
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+  fts5yypParser->fts5yyhwm = 0;
+#endif
+  fts5yypParser->fts5yystack = fts5yypParser->fts5yystk0;
+  fts5yypParser->fts5yystackEnd = &fts5yypParser->fts5yystack[fts5YYSTACKDEPTH-1];
+#ifndef fts5YYNOERRORRECOVERY
+  fts5yypParser->fts5yyerrcnt = -1;
+#endif
+  fts5yypParser->fts5yytos = fts5yypParser->fts5yystack;
+  fts5yypParser->fts5yystack[0].stateno = 0;
+  fts5yypParser->fts5yystack[0].major = 0;
+}
+
+#ifndef sqlite3Fts5Parser_ENGINEALWAYSONSTACK
+/*
+** This function allocates a new parser.
+** The only argument is a pointer to a function which works like
+** malloc.
+**
+** Inputs:
+** A pointer to the function used to allocate memory.
+**
+** Outputs:
+** A pointer to a parser.  This pointer is used in subsequent calls
+** to sqlite3Fts5Parser and sqlite3Fts5ParserFree.
+*/
+static void *sqlite3Fts5ParserAlloc(void *(*mallocProc)(fts5YYMALLOCARGTYPE) sqlite3Fts5ParserCTX_PDECL){
+  fts5yyParser *fts5yypParser;
+  fts5yypParser = (fts5yyParser*)(*mallocProc)( (fts5YYMALLOCARGTYPE)sizeof(fts5yyParser) );
+  if( fts5yypParser ){
+    sqlite3Fts5ParserCTX_STORE
+    sqlite3Fts5ParserInit(fts5yypParser sqlite3Fts5ParserCTX_PARAM);
+  }
+  return (void*)fts5yypParser;
+}
+#endif /* sqlite3Fts5Parser_ENGINEALWAYSONSTACK */
+
+
+/* The following function deletes the "minor type" or semantic value
+** associated with a symbol.  The symbol can be either a terminal
+** or nonterminal. "fts5yymajor" is the symbol code, and "fts5yypminor" is
+** a pointer to the value to be deleted.  The code used to do the
+** deletions is derived from the %destructor and/or %token_destructor
+** directives of the input grammar.
+*/
+static void fts5yy_destructor(
+  fts5yyParser *fts5yypParser,    /* The parser */
+  fts5YYCODETYPE fts5yymajor,     /* Type code for object to destroy */
+  fts5YYMINORTYPE *fts5yypminor   /* The object to be destroyed */
+){
+  sqlite3Fts5ParserARG_FETCH
+  sqlite3Fts5ParserCTX_FETCH
+  switch( fts5yymajor ){
+    /* Here is inserted the actions which take place when a
+    ** terminal or non-terminal is destroyed.  This can happen
+    ** when the symbol is popped from the stack during a
+    ** reduce or during error processing or when a parser is
+    ** being destroyed before it is finished parsing.
+    **
+    ** Note: during a reduce, the only symbols destroyed are those
+    ** which appear on the RHS of the rule, but which are *not* used
+    ** inside the C code.
+    */
+/********* Begin destructor definitions ***************************************/
+    case 16: /* input */
+{
+ (void)pParse;
+}
+      break;
+    case 17: /* expr */
+    case 18: /* cnearset */
+    case 19: /* exprlist */
+{
+ sqlite3Fts5ParseNodeFree((fts5yypminor->fts5yy24));
+}
+      break;
+    case 20: /* colset */
+    case 21: /* colsetlist */
+{
+ sqlite3_free((fts5yypminor->fts5yy11));
+}
+      break;
+    case 22: /* nearset */
+    case 23: /* nearphrases */
+{
+ sqlite3Fts5ParseNearsetFree((fts5yypminor->fts5yy46));
+}
+      break;
+    case 24: /* phrase */
+{
+ sqlite3Fts5ParsePhraseFree((fts5yypminor->fts5yy53));
+}
+      break;
+/********* End destructor definitions *****************************************/
+    default:  break;   /* If no destructor action specified: do nothing */
+  }
+}
+
+/*
+** Pop the parser's stack once.
+**
+** If there is a destructor routine associated with the token which
+** is popped from the stack, then call it.
+*/
+static void fts5yy_pop_parser_stack(fts5yyParser *pParser){
+  fts5yyStackEntry *fts5yytos;
+  assert( pParser->fts5yytos!=0 );
+  assert( pParser->fts5yytos > pParser->fts5yystack );
+  fts5yytos = pParser->fts5yytos--;
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fprintf(fts5yyTraceFILE,"%sPopping %s\n",
+      fts5yyTracePrompt,
+      fts5yyTokenName[fts5yytos->major]);
+  }
+#endif
+  fts5yy_destructor(pParser, fts5yytos->major, &fts5yytos->minor);
+}
+
+/*
+** Clear all secondary memory allocations from the parser
+*/
+static void sqlite3Fts5ParserFinalize(void *p){
+  fts5yyParser *pParser = (fts5yyParser*)p;
+
+  /* In-lined version of calling fts5yy_pop_parser_stack() for each
+  ** element left in the stack */
+  fts5yyStackEntry *fts5yytos = pParser->fts5yytos;
+  while( fts5yytos>pParser->fts5yystack ){
+#ifndef NDEBUG
+    if( fts5yyTraceFILE ){
+      fprintf(fts5yyTraceFILE,"%sPopping %s\n",
+        fts5yyTracePrompt,
+        fts5yyTokenName[fts5yytos->major]);
+    }
+#endif
+    if( fts5yytos->major>=fts5YY_MIN_DSTRCTR ){
+      fts5yy_destructor(pParser, fts5yytos->major, &fts5yytos->minor);
+    }
+    fts5yytos--;
+  }
+
+#if fts5YYGROWABLESTACK
+  if( pParser->fts5yystack!=pParser->fts5yystk0 ) fts5YYFREE(pParser->fts5yystack);
+#endif
+}
+
+#ifndef sqlite3Fts5Parser_ENGINEALWAYSONSTACK
+/*
+** Deallocate and destroy a parser.  Destructors are called for
+** all stack elements before shutting the parser down.
+**
+** If the fts5YYPARSEFREENEVERNULL macro exists (for example because it
+** is defined in a %include section of the input grammar) then it is
+** assumed that the input pointer is never NULL.
+*/
+static void sqlite3Fts5ParserFree(
+  void *p,                    /* The parser to be deleted */
+  void (*freeProc)(void*)     /* Function used to reclaim memory */
+){
+#ifndef fts5YYPARSEFREENEVERNULL
+  if( p==0 ) return;
+#endif
+  sqlite3Fts5ParserFinalize(p);
+  (*freeProc)(p);
+}
+#endif /* sqlite3Fts5Parser_ENGINEALWAYSONSTACK */
+
+/*
+** Return the peak depth of the stack for a parser.
+*/
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+static int sqlite3Fts5ParserStackPeak(void *p){
+  fts5yyParser *pParser = (fts5yyParser*)p;
+  return pParser->fts5yyhwm;
+}
+#endif
+
+/* This array of booleans keeps track of the parser statement
+** coverage.  The element fts5yycoverage[X][Y] is set when the parser
+** is in state X and has a lookahead token Y.  In a well-tested
+** systems, every element of this matrix should end up being set.
+*/
+#if defined(fts5YYCOVERAGE)
+static unsigned char fts5yycoverage[fts5YYNSTATE][fts5YYNFTS5TOKEN];
+#endif
+
+/*
+** Write into out a description of every state/lookahead combination that
+**
+**   (1)  has not been used by the parser, and
+**   (2)  is not a syntax error.
+**
+** Return the number of missed state/lookahead combinations.
+*/
+#if defined(fts5YYCOVERAGE)
+static int sqlite3Fts5ParserCoverage(FILE *out){
+  int stateno, iLookAhead, i;
+  int nMissed = 0;
+  for(stateno=0; stateno<fts5YYNSTATE; stateno++){
+    i = fts5yy_shift_ofst[stateno];
+    for(iLookAhead=0; iLookAhead<fts5YYNFTS5TOKEN; iLookAhead++){
+      if( fts5yy_lookahead[i+iLookAhead]!=iLookAhead ) continue;
+      if( fts5yycoverage[stateno][iLookAhead]==0 ) nMissed++;
+      if( out ){
+        fprintf(out,"State %d lookahead %s %s\n", stateno,
+                fts5yyTokenName[iLookAhead],
+                fts5yycoverage[stateno][iLookAhead] ? "ok" : "missed");
+      }
+    }
+  }
+  return nMissed;
+}
+#endif
+
+/*
+** Find the appropriate action for a parser given the terminal
+** look-ahead token iLookAhead.
+*/
+static fts5YYACTIONTYPE fts5yy_find_shift_action(
+  fts5YYCODETYPE iLookAhead,    /* The look-ahead token */
+  fts5YYACTIONTYPE stateno      /* Current state number */
+){
+  int i;
+
+  if( stateno>fts5YY_MAX_SHIFT ) return stateno;
+  assert( stateno <= fts5YY_SHIFT_COUNT );
+#if defined(fts5YYCOVERAGE)
+  fts5yycoverage[stateno][iLookAhead] = 1;
+#endif
+  do{
+    i = fts5yy_shift_ofst[stateno];
+    assert( i>=0 );
+    assert( i<=fts5YY_ACTTAB_COUNT );
+    assert( i+fts5YYNFTS5TOKEN<=(int)fts5YY_NLOOKAHEAD );
+    assert( iLookAhead!=fts5YYNOCODE );
+    assert( iLookAhead < fts5YYNFTS5TOKEN );
+    i += iLookAhead;
+    assert( i<(int)fts5YY_NLOOKAHEAD );
+    if( fts5yy_lookahead[i]!=iLookAhead ){
+#ifdef fts5YYFALLBACK
+      fts5YYCODETYPE iFallback;            /* Fallback token */
+      assert( iLookAhead<sizeof(fts5yyFallback)/sizeof(fts5yyFallback[0]) );
+      iFallback = fts5yyFallback[iLookAhead];
+      if( iFallback!=0 ){
+#ifndef NDEBUG
+        if( fts5yyTraceFILE ){
+          fprintf(fts5yyTraceFILE, "%sFALLBACK %s => %s\n",
+             fts5yyTracePrompt, fts5yyTokenName[iLookAhead], fts5yyTokenName[iFallback]);
+        }
+#endif
+        assert( fts5yyFallback[iFallback]==0 ); /* Fallback loop must terminate */
+        iLookAhead = iFallback;
+        continue;
+      }
+#endif
+#ifdef fts5YYWILDCARD
+      {
+        int j = i - iLookAhead + fts5YYWILDCARD;
+        assert( j<(int)(sizeof(fts5yy_lookahead)/sizeof(fts5yy_lookahead[0])) );
+        if( fts5yy_lookahead[j]==fts5YYWILDCARD && iLookAhead>0 ){
+#ifndef NDEBUG
+          if( fts5yyTraceFILE ){
+            fprintf(fts5yyTraceFILE, "%sWILDCARD %s => %s\n",
+               fts5yyTracePrompt, fts5yyTokenName[iLookAhead],
+               fts5yyTokenName[fts5YYWILDCARD]);
+          }
+#endif /* NDEBUG */
+          return fts5yy_action[j];
+        }
+      }
+#endif /* fts5YYWILDCARD */
+      return fts5yy_default[stateno];
+    }else{
+      assert( i>=0 && i<(int)(sizeof(fts5yy_action)/sizeof(fts5yy_action[0])) );
+      return fts5yy_action[i];
+    }
+  }while(1);
+}
+
+/*
+** Find the appropriate action for a parser given the non-terminal
+** look-ahead token iLookAhead.
+*/
+static fts5YYACTIONTYPE fts5yy_find_reduce_action(
+  fts5YYACTIONTYPE stateno,     /* Current state number */
+  fts5YYCODETYPE iLookAhead     /* The look-ahead token */
+){
+  int i;
+#ifdef fts5YYERRORSYMBOL
+  if( stateno>fts5YY_REDUCE_COUNT ){
+    return fts5yy_default[stateno];
+  }
+#else
+  assert( stateno<=fts5YY_REDUCE_COUNT );
+#endif
+  i = fts5yy_reduce_ofst[stateno];
+  assert( iLookAhead!=fts5YYNOCODE );
+  i += iLookAhead;
+#ifdef fts5YYERRORSYMBOL
+  if( i<0 || i>=fts5YY_ACTTAB_COUNT || fts5yy_lookahead[i]!=iLookAhead ){
+    return fts5yy_default[stateno];
+  }
+#else
+  assert( i>=0 && i<fts5YY_ACTTAB_COUNT );
+  assert( fts5yy_lookahead[i]==iLookAhead );
+#endif
+  return fts5yy_action[i];
+}
+
+/*
+** The following routine is called if the stack overflows.
+*/
+static void fts5yyStackOverflow(fts5yyParser *fts5yypParser){
+   sqlite3Fts5ParserARG_FETCH
+   sqlite3Fts5ParserCTX_FETCH
+#ifndef NDEBUG
+   if( fts5yyTraceFILE ){
+     fprintf(fts5yyTraceFILE,"%sStack Overflow!\n",fts5yyTracePrompt);
+   }
+#endif
+   while( fts5yypParser->fts5yytos>fts5yypParser->fts5yystack ) fts5yy_pop_parser_stack(fts5yypParser);
+   /* Here code is inserted which will execute if the parser
+   ** stack every overflows */
+/******** Begin %stack_overflow code ******************************************/
+
+  sqlite3Fts5ParseError(pParse, "fts5: parser stack overflow");
+/******** End %stack_overflow code ********************************************/
+   sqlite3Fts5ParserARG_STORE /* Suppress warning about unused %extra_argument var */
+   sqlite3Fts5ParserCTX_STORE
+}
+
+/*
+** Print tracing information for a SHIFT action
+*/
+#ifndef NDEBUG
+static void fts5yyTraceShift(fts5yyParser *fts5yypParser, int fts5yyNewState, const char *zTag){
+  if( fts5yyTraceFILE ){
+    if( fts5yyNewState<fts5YYNSTATE ){
+      fprintf(fts5yyTraceFILE,"%s%s '%s', go to state %d\n",
+         fts5yyTracePrompt, zTag, fts5yyTokenName[fts5yypParser->fts5yytos->major],
+         fts5yyNewState);
+    }else{
+      fprintf(fts5yyTraceFILE,"%s%s '%s', pending reduce %d\n",
+         fts5yyTracePrompt, zTag, fts5yyTokenName[fts5yypParser->fts5yytos->major],
+         fts5yyNewState - fts5YY_MIN_REDUCE);
+    }
+  }
+}
+#else
+# define fts5yyTraceShift(X,Y,Z)
+#endif
+
+/*
+** Perform a shift action.
+*/
+static void fts5yy_shift(
+  fts5yyParser *fts5yypParser,          /* The parser to be shifted */
+  fts5YYACTIONTYPE fts5yyNewState,      /* The new state to shift in */
+  fts5YYCODETYPE fts5yyMajor,           /* The major token to shift in */
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yyMinor        /* The minor token to shift in */
+){
+  fts5yyStackEntry *fts5yytos;
+  fts5yypParser->fts5yytos++;
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+  if( (int)(fts5yypParser->fts5yytos - fts5yypParser->fts5yystack)>fts5yypParser->fts5yyhwm ){
+    fts5yypParser->fts5yyhwm++;
+    assert( fts5yypParser->fts5yyhwm == (int)(fts5yypParser->fts5yytos - fts5yypParser->fts5yystack) );
+  }
+#endif
+  fts5yytos = fts5yypParser->fts5yytos;
+  if( fts5yytos>fts5yypParser->fts5yystackEnd ){
+    if( fts5yyGrowStack(fts5yypParser) ){
+      fts5yypParser->fts5yytos--;
+      fts5yyStackOverflow(fts5yypParser);
+      return;
+    }
+    fts5yytos = fts5yypParser->fts5yytos;
+    assert( fts5yytos <= fts5yypParser->fts5yystackEnd );
+  }
+  if( fts5yyNewState > fts5YY_MAX_SHIFT ){
+    fts5yyNewState += fts5YY_MIN_REDUCE - fts5YY_MIN_SHIFTREDUCE;
+  }
+  fts5yytos->stateno = fts5yyNewState;
+  fts5yytos->major = fts5yyMajor;
+  fts5yytos->minor.fts5yy0 = fts5yyMinor;
+  fts5yyTraceShift(fts5yypParser, fts5yyNewState, "Shift");
+}
+
+/* For rule J, fts5yyRuleInfoLhs[J] contains the symbol on the left-hand side
+** of that rule */
+static const fts5YYCODETYPE fts5yyRuleInfoLhs[] = {
+    16,  /* (0) input ::= expr */
+    20,  /* (1) colset ::= MINUS LCP colsetlist RCP */
+    20,  /* (2) colset ::= LCP colsetlist RCP */
+    20,  /* (3) colset ::= STRING */
+    20,  /* (4) colset ::= MINUS STRING */
+    21,  /* (5) colsetlist ::= colsetlist STRING */
+    21,  /* (6) colsetlist ::= STRING */
+    17,  /* (7) expr ::= expr AND expr */
+    17,  /* (8) expr ::= expr OR expr */
+    17,  /* (9) expr ::= expr NOT expr */
+    17,  /* (10) expr ::= colset COLON LP expr RP */
+    17,  /* (11) expr ::= LP expr RP */
+    17,  /* (12) expr ::= exprlist */
+    19,  /* (13) exprlist ::= cnearset */
+    19,  /* (14) exprlist ::= exprlist cnearset */
+    18,  /* (15) cnearset ::= nearset */
+    18,  /* (16) cnearset ::= colset COLON nearset */
+    22,  /* (17) nearset ::= phrase */
+    22,  /* (18) nearset ::= CARET phrase */
+    22,  /* (19) nearset ::= STRING LP nearphrases neardist_opt RP */
+    23,  /* (20) nearphrases ::= phrase */
+    23,  /* (21) nearphrases ::= nearphrases phrase */
+    25,  /* (22) neardist_opt ::= */
+    25,  /* (23) neardist_opt ::= COMMA STRING */
+    24,  /* (24) phrase ::= phrase PLUS STRING star_opt */
+    24,  /* (25) phrase ::= STRING star_opt */
+    26,  /* (26) star_opt ::= STAR */
+    26,  /* (27) star_opt ::= */
+};
+
+/* For rule J, fts5yyRuleInfoNRhs[J] contains the negative of the number
+** of symbols on the right-hand side of that rule. */
+static const signed char fts5yyRuleInfoNRhs[] = {
+   -1,  /* (0) input ::= expr */
+   -4,  /* (1) colset ::= MINUS LCP colsetlist RCP */
+   -3,  /* (2) colset ::= LCP colsetlist RCP */
+   -1,  /* (3) colset ::= STRING */
+   -2,  /* (4) colset ::= MINUS STRING */
+   -2,  /* (5) colsetlist ::= colsetlist STRING */
+   -1,  /* (6) colsetlist ::= STRING */
+   -3,  /* (7) expr ::= expr AND expr */
+   -3,  /* (8) expr ::= expr OR expr */
+   -3,  /* (9) expr ::= expr NOT expr */
+   -5,  /* (10) expr ::= colset COLON LP expr RP */
+   -3,  /* (11) expr ::= LP expr RP */
+   -1,  /* (12) expr ::= exprlist */
+   -1,  /* (13) exprlist ::= cnearset */
+   -2,  /* (14) exprlist ::= exprlist cnearset */
+   -1,  /* (15) cnearset ::= nearset */
+   -3,  /* (16) cnearset ::= colset COLON nearset */
+   -1,  /* (17) nearset ::= phrase */
+   -2,  /* (18) nearset ::= CARET phrase */
+   -5,  /* (19) nearset ::= STRING LP nearphrases neardist_opt RP */
+   -1,  /* (20) nearphrases ::= phrase */
+   -2,  /* (21) nearphrases ::= nearphrases phrase */
+    0,  /* (22) neardist_opt ::= */
+   -2,  /* (23) neardist_opt ::= COMMA STRING */
+   -4,  /* (24) phrase ::= phrase PLUS STRING star_opt */
+   -2,  /* (25) phrase ::= STRING star_opt */
+   -1,  /* (26) star_opt ::= STAR */
+    0,  /* (27) star_opt ::= */
+};
+
+static void fts5yy_accept(fts5yyParser*);  /* Forward Declaration */
+
+/*
+** Perform a reduce action and the shift that must immediately
+** follow the reduce.
+**
+** The fts5yyLookahead and fts5yyLookaheadToken parameters provide reduce actions
+** access to the lookahead token (if any).  The fts5yyLookahead will be fts5YYNOCODE
+** if the lookahead token has already been consumed.  As this procedure is
+** only called from one place, optimizing compilers will in-line it, which
+** means that the extra parameters have no performance impact.
+*/
+static fts5YYACTIONTYPE fts5yy_reduce(
+  fts5yyParser *fts5yypParser,         /* The parser */
+  unsigned int fts5yyruleno,       /* Number of the rule by which to reduce */
+  int fts5yyLookahead,             /* Lookahead token, or fts5YYNOCODE if none */
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yyLookaheadToken  /* Value of the lookahead token */
+  sqlite3Fts5ParserCTX_PDECL                   /* %extra_context */
+){
+  int fts5yygoto;                     /* The next state */
+  fts5YYACTIONTYPE fts5yyact;             /* The next action */
+  fts5yyStackEntry *fts5yymsp;            /* The top of the parser's stack */
+  int fts5yysize;                     /* Amount to pop the stack */
+  sqlite3Fts5ParserARG_FETCH
+  (void)fts5yyLookahead;
+  (void)fts5yyLookaheadToken;
+  fts5yymsp = fts5yypParser->fts5yytos;
+
+  switch( fts5yyruleno ){
+  /* Beginning here are the reduction cases.  A typical example
+  ** follows:
+  **   case 0:
+  **  #line <lineno> <grammarfile>
+  **     { ... }           // User supplied code
+  **  #line <lineno> <thisfile>
+  **     break;
+  */
+/********** Begin reduce actions **********************************************/
+        fts5YYMINORTYPE fts5yylhsminor;
+      case 0: /* input ::= expr */
+{ sqlite3Fts5ParseFinished(pParse, fts5yymsp[0].minor.fts5yy24); }
+        break;
+      case 1: /* colset ::= MINUS LCP colsetlist RCP */
+{
+    fts5yymsp[-3].minor.fts5yy11 = sqlite3Fts5ParseColsetInvert(pParse, fts5yymsp[-1].minor.fts5yy11);
+}
+        break;
+      case 2: /* colset ::= LCP colsetlist RCP */
+{ fts5yymsp[-2].minor.fts5yy11 = fts5yymsp[-1].minor.fts5yy11; }
+        break;
+      case 3: /* colset ::= STRING */
+{
+  fts5yylhsminor.fts5yy11 = sqlite3Fts5ParseColset(pParse, 0, &fts5yymsp[0].minor.fts5yy0);
+}
+  fts5yymsp[0].minor.fts5yy11 = fts5yylhsminor.fts5yy11;
+        break;
+      case 4: /* colset ::= MINUS STRING */
+{
+  fts5yymsp[-1].minor.fts5yy11 = sqlite3Fts5ParseColset(pParse, 0, &fts5yymsp[0].minor.fts5yy0);
+  fts5yymsp[-1].minor.fts5yy11 = sqlite3Fts5ParseColsetInvert(pParse, fts5yymsp[-1].minor.fts5yy11);
+}
+        break;
+      case 5: /* colsetlist ::= colsetlist STRING */
+{
+  fts5yylhsminor.fts5yy11 = sqlite3Fts5ParseColset(pParse, fts5yymsp[-1].minor.fts5yy11, &fts5yymsp[0].minor.fts5yy0); }
+  fts5yymsp[-1].minor.fts5yy11 = fts5yylhsminor.fts5yy11;
+        break;
+      case 6: /* colsetlist ::= STRING */
+{
+  fts5yylhsminor.fts5yy11 = sqlite3Fts5ParseColset(pParse, 0, &fts5yymsp[0].minor.fts5yy0);
+}
+  fts5yymsp[0].minor.fts5yy11 = fts5yylhsminor.fts5yy11;
+        break;
+      case 7: /* expr ::= expr AND expr */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_AND, fts5yymsp[-2].minor.fts5yy24, fts5yymsp[0].minor.fts5yy24, 0);
+}
+  fts5yymsp[-2].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 8: /* expr ::= expr OR expr */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_OR, fts5yymsp[-2].minor.fts5yy24, fts5yymsp[0].minor.fts5yy24, 0);
+}
+  fts5yymsp[-2].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 9: /* expr ::= expr NOT expr */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_NOT, fts5yymsp[-2].minor.fts5yy24, fts5yymsp[0].minor.fts5yy24, 0);
+}
+  fts5yymsp[-2].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 10: /* expr ::= colset COLON LP expr RP */
+{
+  sqlite3Fts5ParseSetColset(pParse, fts5yymsp[-1].minor.fts5yy24, fts5yymsp[-4].minor.fts5yy11);
+  fts5yylhsminor.fts5yy24 = fts5yymsp[-1].minor.fts5yy24;
+}
+  fts5yymsp[-4].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 11: /* expr ::= LP expr RP */
+{fts5yymsp[-2].minor.fts5yy24 = fts5yymsp[-1].minor.fts5yy24;}
+        break;
+      case 12: /* expr ::= exprlist */
+      case 13: /* exprlist ::= cnearset */ fts5yytestcase(fts5yyruleno==13);
+{fts5yylhsminor.fts5yy24 = fts5yymsp[0].minor.fts5yy24;}
+  fts5yymsp[0].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 14: /* exprlist ::= exprlist cnearset */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseImplicitAnd(pParse, fts5yymsp[-1].minor.fts5yy24, fts5yymsp[0].minor.fts5yy24);
+}
+  fts5yymsp[-1].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 15: /* cnearset ::= nearset */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_STRING, 0, 0, fts5yymsp[0].minor.fts5yy46);
+}
+  fts5yymsp[0].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 16: /* cnearset ::= colset COLON nearset */
+{
+  fts5yylhsminor.fts5yy24 = sqlite3Fts5ParseNode(pParse, FTS5_STRING, 0, 0, fts5yymsp[0].minor.fts5yy46);
+  sqlite3Fts5ParseSetColset(pParse, fts5yylhsminor.fts5yy24, fts5yymsp[-2].minor.fts5yy11);
+}
+  fts5yymsp[-2].minor.fts5yy24 = fts5yylhsminor.fts5yy24;
+        break;
+      case 17: /* nearset ::= phrase */
+{ fts5yylhsminor.fts5yy46 = sqlite3Fts5ParseNearset(pParse, 0, fts5yymsp[0].minor.fts5yy53); }
+  fts5yymsp[0].minor.fts5yy46 = fts5yylhsminor.fts5yy46;
+        break;
+      case 18: /* nearset ::= CARET phrase */
+{
+  sqlite3Fts5ParseSetCaret(fts5yymsp[0].minor.fts5yy53);
+  fts5yymsp[-1].minor.fts5yy46 = sqlite3Fts5ParseNearset(pParse, 0, fts5yymsp[0].minor.fts5yy53);
+}
+        break;
+      case 19: /* nearset ::= STRING LP nearphrases neardist_opt RP */
+{
+  sqlite3Fts5ParseNear(pParse, &fts5yymsp[-4].minor.fts5yy0);
+  sqlite3Fts5ParseSetDistance(pParse, fts5yymsp[-2].minor.fts5yy46, &fts5yymsp[-1].minor.fts5yy0);
+  fts5yylhsminor.fts5yy46 = fts5yymsp[-2].minor.fts5yy46;
+}
+  fts5yymsp[-4].minor.fts5yy46 = fts5yylhsminor.fts5yy46;
+        break;
+      case 20: /* nearphrases ::= phrase */
+{
+  fts5yylhsminor.fts5yy46 = sqlite3Fts5ParseNearset(pParse, 0, fts5yymsp[0].minor.fts5yy53);
+}
+  fts5yymsp[0].minor.fts5yy46 = fts5yylhsminor.fts5yy46;
+        break;
+      case 21: /* nearphrases ::= nearphrases phrase */
+{
+  fts5yylhsminor.fts5yy46 = sqlite3Fts5ParseNearset(pParse, fts5yymsp[-1].minor.fts5yy46, fts5yymsp[0].minor.fts5yy53);
+}
+  fts5yymsp[-1].minor.fts5yy46 = fts5yylhsminor.fts5yy46;
+        break;
+      case 22: /* neardist_opt ::= */
+{ fts5yymsp[1].minor.fts5yy0.p = 0; fts5yymsp[1].minor.fts5yy0.n = 0; }
+        break;
+      case 23: /* neardist_opt ::= COMMA STRING */
+{ fts5yymsp[-1].minor.fts5yy0 = fts5yymsp[0].minor.fts5yy0; }
+        break;
+      case 24: /* phrase ::= phrase PLUS STRING star_opt */
+{
+  fts5yylhsminor.fts5yy53 = sqlite3Fts5ParseTerm(pParse, fts5yymsp[-3].minor.fts5yy53, &fts5yymsp[-1].minor.fts5yy0, fts5yymsp[0].minor.fts5yy4);
+}
+  fts5yymsp[-3].minor.fts5yy53 = fts5yylhsminor.fts5yy53;
+        break;
+      case 25: /* phrase ::= STRING star_opt */
+{
+  fts5yylhsminor.fts5yy53 = sqlite3Fts5ParseTerm(pParse, 0, &fts5yymsp[-1].minor.fts5yy0, fts5yymsp[0].minor.fts5yy4);
+}
+  fts5yymsp[-1].minor.fts5yy53 = fts5yylhsminor.fts5yy53;
+        break;
+      case 26: /* star_opt ::= STAR */
+{ fts5yymsp[0].minor.fts5yy4 = 1; }
+        break;
+      case 27: /* star_opt ::= */
+{ fts5yymsp[1].minor.fts5yy4 = 0; }
+        break;
+      default:
+        break;
+/********** End reduce actions ************************************************/
+  };
+  assert( fts5yyruleno<sizeof(fts5yyRuleInfoLhs)/sizeof(fts5yyRuleInfoLhs[0]) );
+  fts5yygoto = fts5yyRuleInfoLhs[fts5yyruleno];
+  fts5yysize = fts5yyRuleInfoNRhs[fts5yyruleno];
+  fts5yyact = fts5yy_find_reduce_action(fts5yymsp[fts5yysize].stateno,(fts5YYCODETYPE)fts5yygoto);
+
+  /* There are no SHIFTREDUCE actions on nonterminals because the table
+  ** generator has simplified them to pure REDUCE actions. */
+  assert( !(fts5yyact>fts5YY_MAX_SHIFT && fts5yyact<=fts5YY_MAX_SHIFTREDUCE) );
+
+  /* It is not possible for a REDUCE to be followed by an error */
+  assert( fts5yyact!=fts5YY_ERROR_ACTION );
+
+  fts5yymsp += fts5yysize+1;
+  fts5yypParser->fts5yytos = fts5yymsp;
+  fts5yymsp->stateno = (fts5YYACTIONTYPE)fts5yyact;
+  fts5yymsp->major = (fts5YYCODETYPE)fts5yygoto;
+  fts5yyTraceShift(fts5yypParser, fts5yyact, "... then shift");
+  return fts5yyact;
+}
+
+/*
+** The following code executes when the parse fails
+*/
+#ifndef fts5YYNOERRORRECOVERY
+static void fts5yy_parse_failed(
+  fts5yyParser *fts5yypParser           /* The parser */
+){
+  sqlite3Fts5ParserARG_FETCH
+  sqlite3Fts5ParserCTX_FETCH
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fprintf(fts5yyTraceFILE,"%sFail!\n",fts5yyTracePrompt);
+  }
+#endif
+  while( fts5yypParser->fts5yytos>fts5yypParser->fts5yystack ) fts5yy_pop_parser_stack(fts5yypParser);
+  /* Here code is inserted which will be executed whenever the
+  ** parser fails */
+/************ Begin %parse_failure code ***************************************/
+/************ End %parse_failure code *****************************************/
+  sqlite3Fts5ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3Fts5ParserCTX_STORE
+}
+#endif /* fts5YYNOERRORRECOVERY */
+
+/*
+** The following code executes when a syntax error first occurs.
+*/
+static void fts5yy_syntax_error(
+  fts5yyParser *fts5yypParser,           /* The parser */
+  int fts5yymajor,                   /* The major type of the error token */
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yyminor         /* The minor type of the error token */
+){
+  sqlite3Fts5ParserARG_FETCH
+  sqlite3Fts5ParserCTX_FETCH
+#define FTS5TOKEN fts5yyminor
+/************ Begin %syntax_error code ****************************************/
+
+  UNUSED_PARAM(fts5yymajor); /* Silence a compiler warning */
+  sqlite3Fts5ParseError(
+    pParse, "fts5: syntax error near \"%.*s\"",FTS5TOKEN.n,FTS5TOKEN.p
+  );
+/************ End %syntax_error code ******************************************/
+  sqlite3Fts5ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3Fts5ParserCTX_STORE
+}
+
+/*
+** The following is executed when the parser accepts
+*/
+static void fts5yy_accept(
+  fts5yyParser *fts5yypParser           /* The parser */
+){
+  sqlite3Fts5ParserARG_FETCH
+  sqlite3Fts5ParserCTX_FETCH
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fprintf(fts5yyTraceFILE,"%sAccept!\n",fts5yyTracePrompt);
+  }
+#endif
+#ifndef fts5YYNOERRORRECOVERY
+  fts5yypParser->fts5yyerrcnt = -1;
+#endif
+  assert( fts5yypParser->fts5yytos==fts5yypParser->fts5yystack );
+  /* Here code is inserted which will be executed whenever the
+  ** parser accepts */
+/*********** Begin %parse_accept code *****************************************/
+/*********** End %parse_accept code *******************************************/
+  sqlite3Fts5ParserARG_STORE /* Suppress warning about unused %extra_argument variable */
+  sqlite3Fts5ParserCTX_STORE
+}
+
+/* The main parser program.
+** The first argument is a pointer to a structure obtained from
+** "sqlite3Fts5ParserAlloc" which describes the current state of the parser.
+** The second argument is the major token number.  The third is
+** the minor token.  The fourth optional argument is whatever the
+** user wants (and specified in the grammar) and is available for
+** use by the action routines.
+**
+** Inputs:
+** <ul>
+** <li> A pointer to the parser (an opaque structure.)
+** <li> The major token number.
+** <li> The minor token number.
+** <li> An option argument of a grammar-specified type.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+static void sqlite3Fts5Parser(
+  void *fts5yyp,                   /* The parser */
+  int fts5yymajor,                 /* The major token code number */
+  sqlite3Fts5ParserFTS5TOKENTYPE fts5yyminor       /* The value for the token */
+  sqlite3Fts5ParserARG_PDECL               /* Optional %extra_argument parameter */
+){
+  fts5YYMINORTYPE fts5yyminorunion;
+  fts5YYACTIONTYPE fts5yyact;   /* The parser action. */
+#if !defined(fts5YYERRORSYMBOL) && !defined(fts5YYNOERRORRECOVERY)
+  int fts5yyendofinput;     /* True if we are at the end of input */
+#endif
+#ifdef fts5YYERRORSYMBOL
+  int fts5yyerrorhit = 0;   /* True if fts5yymajor has invoked an error */
+#endif
+  fts5yyParser *fts5yypParser = (fts5yyParser*)fts5yyp;  /* The parser */
+  sqlite3Fts5ParserCTX_FETCH
+  sqlite3Fts5ParserARG_STORE
+
+  assert( fts5yypParser->fts5yytos!=0 );
+#if !defined(fts5YYERRORSYMBOL) && !defined(fts5YYNOERRORRECOVERY)
+  fts5yyendofinput = (fts5yymajor==0);
+#endif
+
+  fts5yyact = fts5yypParser->fts5yytos->stateno;
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    if( fts5yyact < fts5YY_MIN_REDUCE ){
+      fprintf(fts5yyTraceFILE,"%sInput '%s' in state %d\n",
+              fts5yyTracePrompt,fts5yyTokenName[fts5yymajor],fts5yyact);
+    }else{
+      fprintf(fts5yyTraceFILE,"%sInput '%s' with pending reduce %d\n",
+              fts5yyTracePrompt,fts5yyTokenName[fts5yymajor],fts5yyact-fts5YY_MIN_REDUCE);
+    }
+  }
+#endif
+
+  while(1){ /* Exit by "break" */
+    assert( fts5yypParser->fts5yytos>=fts5yypParser->fts5yystack );
+    assert( fts5yyact==fts5yypParser->fts5yytos->stateno );
+    fts5yyact = fts5yy_find_shift_action((fts5YYCODETYPE)fts5yymajor,fts5yyact);
+    if( fts5yyact >= fts5YY_MIN_REDUCE ){
+      unsigned int fts5yyruleno = fts5yyact - fts5YY_MIN_REDUCE; /* Reduce by this rule */
+#ifndef NDEBUG
+      assert( fts5yyruleno<(int)(sizeof(fts5yyRuleName)/sizeof(fts5yyRuleName[0])) );
+      if( fts5yyTraceFILE ){
+        int fts5yysize = fts5yyRuleInfoNRhs[fts5yyruleno];
+        if( fts5yysize ){
+          fprintf(fts5yyTraceFILE, "%sReduce %d [%s]%s, pop back to state %d.\n",
+            fts5yyTracePrompt,
+            fts5yyruleno, fts5yyRuleName[fts5yyruleno],
+            fts5yyruleno<fts5YYNRULE_WITH_ACTION ? "" : " without external action",
+            fts5yypParser->fts5yytos[fts5yysize].stateno);
+        }else{
+          fprintf(fts5yyTraceFILE, "%sReduce %d [%s]%s.\n",
+            fts5yyTracePrompt, fts5yyruleno, fts5yyRuleName[fts5yyruleno],
+            fts5yyruleno<fts5YYNRULE_WITH_ACTION ? "" : " without external action");
+        }
+      }
+#endif /* NDEBUG */
+
+      /* Check that the stack is large enough to grow by a single entry
+      ** if the RHS of the rule is empty.  This ensures that there is room
+      ** enough on the stack to push the LHS value */
+      if( fts5yyRuleInfoNRhs[fts5yyruleno]==0 ){
+#ifdef fts5YYTRACKMAXSTACKDEPTH
+        if( (int)(fts5yypParser->fts5yytos - fts5yypParser->fts5yystack)>fts5yypParser->fts5yyhwm ){
+          fts5yypParser->fts5yyhwm++;
+          assert( fts5yypParser->fts5yyhwm ==
+                  (int)(fts5yypParser->fts5yytos - fts5yypParser->fts5yystack));
+        }
+#endif
+        if( fts5yypParser->fts5yytos>=fts5yypParser->fts5yystackEnd ){
+          if( fts5yyGrowStack(fts5yypParser) ){
+            fts5yyStackOverflow(fts5yypParser);
+            break;
+          }
+        }
+      }
+      fts5yyact = fts5yy_reduce(fts5yypParser,fts5yyruleno,fts5yymajor,fts5yyminor sqlite3Fts5ParserCTX_PARAM);
+    }else if( fts5yyact <= fts5YY_MAX_SHIFTREDUCE ){
+      fts5yy_shift(fts5yypParser,fts5yyact,(fts5YYCODETYPE)fts5yymajor,fts5yyminor);
+#ifndef fts5YYNOERRORRECOVERY
+      fts5yypParser->fts5yyerrcnt--;
+#endif
+      break;
+    }else if( fts5yyact==fts5YY_ACCEPT_ACTION ){
+      fts5yypParser->fts5yytos--;
+      fts5yy_accept(fts5yypParser);
+      return;
+    }else{
+      assert( fts5yyact == fts5YY_ERROR_ACTION );
+      fts5yyminorunion.fts5yy0 = fts5yyminor;
+#ifdef fts5YYERRORSYMBOL
+      int fts5yymx;
+#endif
+#ifndef NDEBUG
+      if( fts5yyTraceFILE ){
+        fprintf(fts5yyTraceFILE,"%sSyntax Error!\n",fts5yyTracePrompt);
+      }
+#endif
+#ifdef fts5YYERRORSYMBOL
+      /* A syntax error has occurred.
+      ** The response to an error depends upon whether or not the
+      ** grammar defines an error token "ERROR".
+      **
+      ** This is what we do if the grammar does define ERROR:
+      **
+      **  * Call the %syntax_error function.
+      **
+      **  * Begin popping the stack until we enter a state where
+      **    it is legal to shift the error symbol, then shift
+      **    the error symbol.
+      **
+      **  * Set the error count to three.
+      **
+      **  * Begin accepting and shifting new tokens.  No new error
+      **    processing will occur until three tokens have been
+      **    shifted successfully.
+      **
+      */
+      if( fts5yypParser->fts5yyerrcnt<0 ){
+        fts5yy_syntax_error(fts5yypParser,fts5yymajor,fts5yyminor);
+      }
+      fts5yymx = fts5yypParser->fts5yytos->major;
+      if( fts5yymx==fts5YYERRORSYMBOL || fts5yyerrorhit ){
+#ifndef NDEBUG
+        if( fts5yyTraceFILE ){
+          fprintf(fts5yyTraceFILE,"%sDiscard input token %s\n",
+             fts5yyTracePrompt,fts5yyTokenName[fts5yymajor]);
+        }
+#endif
+        fts5yy_destructor(fts5yypParser, (fts5YYCODETYPE)fts5yymajor, &fts5yyminorunion);
+        fts5yymajor = fts5YYNOCODE;
+      }else{
+        while( fts5yypParser->fts5yytos > fts5yypParser->fts5yystack ){
+          fts5yyact = fts5yy_find_reduce_action(fts5yypParser->fts5yytos->stateno,
+                                        fts5YYERRORSYMBOL);
+          if( fts5yyact<=fts5YY_MAX_SHIFTREDUCE ) break;
+          fts5yy_pop_parser_stack(fts5yypParser);
+        }
+        if( fts5yypParser->fts5yytos <= fts5yypParser->fts5yystack || fts5yymajor==0 ){
+          fts5yy_destructor(fts5yypParser,(fts5YYCODETYPE)fts5yymajor,&fts5yyminorunion);
+          fts5yy_parse_failed(fts5yypParser);
+#ifndef fts5YYNOERRORRECOVERY
+          fts5yypParser->fts5yyerrcnt = -1;
+#endif
+          fts5yymajor = fts5YYNOCODE;
+        }else if( fts5yymx!=fts5YYERRORSYMBOL ){
+          fts5yy_shift(fts5yypParser,fts5yyact,fts5YYERRORSYMBOL,fts5yyminor);
+        }
+      }
+      fts5yypParser->fts5yyerrcnt = 3;
+      fts5yyerrorhit = 1;
+      if( fts5yymajor==fts5YYNOCODE ) break;
+      fts5yyact = fts5yypParser->fts5yytos->stateno;
+#elif defined(fts5YYNOERRORRECOVERY)
+      /* If the fts5YYNOERRORRECOVERY macro is defined, then do not attempt to
+      ** do any kind of error recovery.  Instead, simply invoke the syntax
+      ** error routine and continue going as if nothing had happened.
+      **
+      ** Applications can set this macro (for example inside %include) if
+      ** they intend to abandon the parse upon the first syntax error seen.
+      */
+      fts5yy_syntax_error(fts5yypParser,fts5yymajor, fts5yyminor);
+      fts5yy_destructor(fts5yypParser,(fts5YYCODETYPE)fts5yymajor,&fts5yyminorunion);
+      break;
+#else  /* fts5YYERRORSYMBOL is not defined */
+      /* This is what we do if the grammar does not define ERROR:
+      **
+      **  * Report an error message, and throw away the input token.
+      **
+      **  * If the input token is $, then fail the parse.
+      **
+      ** As before, subsequent error messages are suppressed until
+      ** three input tokens have been successfully shifted.
+      */
+      if( fts5yypParser->fts5yyerrcnt<=0 ){
+        fts5yy_syntax_error(fts5yypParser,fts5yymajor, fts5yyminor);
+      }
+      fts5yypParser->fts5yyerrcnt = 3;
+      fts5yy_destructor(fts5yypParser,(fts5YYCODETYPE)fts5yymajor,&fts5yyminorunion);
+      if( fts5yyendofinput ){
+        fts5yy_parse_failed(fts5yypParser);
+#ifndef fts5YYNOERRORRECOVERY
+        fts5yypParser->fts5yyerrcnt = -1;
+#endif
+      }
+      break;
+#endif
+    }
+  }
+#ifndef NDEBUG
+  if( fts5yyTraceFILE ){
+    fts5yyStackEntry *i;
+    char cDiv = '[';
+    fprintf(fts5yyTraceFILE,"%sReturn. Stack=",fts5yyTracePrompt);
+    for(i=&fts5yypParser->fts5yystack[1]; i<=fts5yypParser->fts5yytos; i++){
+      fprintf(fts5yyTraceFILE,"%c%s", cDiv, fts5yyTokenName[i->major]);
+      cDiv = ' ';
+    }
+    fprintf(fts5yyTraceFILE,"]\n");
+  }
+#endif
+  return;
+}
+
+/*
+** Return the fallback token corresponding to canonical token iToken, or
+** 0 if iToken has no fallback.
+*/
+static int sqlite3Fts5ParserFallback(int iToken){
+#ifdef fts5YYFALLBACK
+  assert( iToken<(int)(sizeof(fts5yyFallback)/sizeof(fts5yyFallback[0])) );
+  return fts5yyFallback[iToken];
+#else
+  (void)iToken;
+  return 0;
+#endif
+}
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+
+/* #include "fts5Int.h" */
+#include <math.h>                 /* amalgamator: keep */
+
+/*
+** Object used to iterate through all "coalesced phrase instances" in
+** a single column of the current row. If the phrase instances in the
+** column being considered do not overlap, this object simply iterates
+** through them. Or, if they do overlap (share one or more tokens in
+** common), each set of overlapping instances is treated as a single
+** match. See documentation for the highlight() auxiliary function for
+** details.
+**
+** Usage is:
+**
+**   for(rc = fts5CInstIterNext(pApi, pFts, iCol, &iter);
+**      (rc==SQLITE_OK && 0==fts5CInstIterEof(&iter);
+**      rc = fts5CInstIterNext(&iter)
+**   ){
+**     printf("instance starts at %d, ends at %d\n", iter.iStart, iter.iEnd);
+**   }
+**
+*/
+typedef struct CInstIter CInstIter;
+struct CInstIter {
+  const Fts5ExtensionApi *pApi;   /* API offered by current FTS version */
+  Fts5Context *pFts;              /* First arg to pass to pApi functions */
+  int iCol;                       /* Column to search */
+  int iInst;                      /* Next phrase instance index */
+  int nInst;                      /* Total number of phrase instances */
+
+  /* Output variables */
+  int iStart;                     /* First token in coalesced phrase instance */
+  int iEnd;                       /* Last token in coalesced phrase instance */
+};
+
+/*
+** Advance the iterator to the next coalesced phrase instance. Return
+** an SQLite error code if an error occurs, or SQLITE_OK otherwise.
+*/
+static int fts5CInstIterNext(CInstIter *pIter){
+  int rc = SQLITE_OK;
+  pIter->iStart = -1;
+  pIter->iEnd = -1;
+
+  while( rc==SQLITE_OK && pIter->iInst<pIter->nInst ){
+    int ip; int ic; int io;
+    rc = pIter->pApi->xInst(pIter->pFts, pIter->iInst, &ip, &ic, &io);
+    if( rc==SQLITE_OK ){
+      if( ic==pIter->iCol ){
+        int iEnd = io - 1 + pIter->pApi->xPhraseSize(pIter->pFts, ip);
+        if( pIter->iStart<0 ){
+          pIter->iStart = io;
+          pIter->iEnd = iEnd;
+        }else if( io<=pIter->iEnd ){
+          if( iEnd>pIter->iEnd ) pIter->iEnd = iEnd;
+        }else{
+          break;
+        }
+      }
+      pIter->iInst++;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Initialize the iterator object indicated by the final parameter to
+** iterate through coalesced phrase instances in column iCol.
+*/
+static int fts5CInstIterInit(
+  const Fts5ExtensionApi *pApi,
+  Fts5Context *pFts,
+  int iCol,
+  CInstIter *pIter
+){
+  int rc;
+
+  memset(pIter, 0, sizeof(CInstIter));
+  pIter->pApi = pApi;
+  pIter->pFts = pFts;
+  pIter->iCol = iCol;
+  rc = pApi->xInstCount(pFts, &pIter->nInst);
+
+  if( rc==SQLITE_OK ){
+    rc = fts5CInstIterNext(pIter);
+  }
+
+  return rc;
+}
+
+
+
+/*************************************************************************
+** Start of highlight() implementation.
+*/
+typedef struct HighlightContext HighlightContext;
+struct HighlightContext {
+  /* Constant parameters to fts5HighlightCb() */
+  int iRangeStart;                /* First token to include */
+  int iRangeEnd;                  /* If non-zero, last token to include */
+  const char *zOpen;              /* Opening highlight */
+  const char *zClose;             /* Closing highlight */
+  const char *zIn;                /* Input text */
+  int nIn;                        /* Size of input text in bytes */
+
+  /* Variables modified by fts5HighlightCb() */
+  CInstIter iter;                 /* Coalesced Instance Iterator */
+  int iPos;                       /* Current token offset in zIn[] */
+  int iOff;                       /* Have copied up to this offset in zIn[] */
+  int bOpen;                      /* True if highlight is open */
+  char *zOut;                     /* Output value */
+};
+
+/*
+** Append text to the HighlightContext output string - p->zOut. Argument
+** z points to a buffer containing n bytes of text to append. If n is
+** negative, everything up until the first '\0' is appended to the output.
+**
+** If *pRc is set to any value other than SQLITE_OK when this function is
+** called, it is a no-op. If an error (i.e. an OOM condition) is encountered,
+** *pRc is set to an error code before returning.
+*/
+static void fts5HighlightAppend(
+  int *pRc,
+  HighlightContext *p,
+  const char *z, int n
+){
+  if( *pRc==SQLITE_OK && z ){
+    if( n<0 ) n = (int)strlen(z);
+    p->zOut = sqlite3_mprintf("%z%.*s", p->zOut, n, z);
+    if( p->zOut==0 ) *pRc = SQLITE_NOMEM;
+  }
+}
+
+/*
+** Tokenizer callback used by implementation of highlight() function.
+*/
+static int fts5HighlightCb(
+  void *pContext,                 /* Pointer to HighlightContext object */
+  int tflags,                     /* Mask of FTS5_TOKEN_* flags */
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iStartOff,                  /* Start byte offset of token */
+  int iEndOff                     /* End byte offset of token */
+){
+  HighlightContext *p = (HighlightContext*)pContext;
+  int rc = SQLITE_OK;
+  int iPos;
+
+  UNUSED_PARAM2(pToken, nToken);
+
+  if( tflags & FTS5_TOKEN_COLOCATED ) return SQLITE_OK;
+  iPos = p->iPos++;
+
+  if( p->iRangeEnd>=0 ){
+    if( iPos<p->iRangeStart || iPos>p->iRangeEnd ) return SQLITE_OK;
+    if( p->iRangeStart && iPos==p->iRangeStart ) p->iOff = iStartOff;
+  }
+
+  /* If the parenthesis is open, and this token is not part of the current
+  ** phrase, and the starting byte offset of this token is past the point
+  ** that has currently been copied into the output buffer, close the
+  ** parenthesis. */
+  if( p->bOpen
+   && (iPos<=p->iter.iStart || p->iter.iStart<0)
+   && iStartOff>p->iOff
+  ){
+    fts5HighlightAppend(&rc, p, p->zClose, -1);
+    p->bOpen = 0;
+  }
+
+  /* If this is the start of a new phrase, and the highlight is not open:
+  **
+  **   * copy text from the input up to the start of the phrase, and
+  **   * open the highlight.
+  */
+  if( iPos==p->iter.iStart && p->bOpen==0 ){
+    fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iStartOff - p->iOff);
+    fts5HighlightAppend(&rc, p, p->zOpen, -1);
+    p->iOff = iStartOff;
+    p->bOpen = 1;
+  }
+
+  if( iPos==p->iter.iEnd ){
+    if( p->bOpen==0 ){
+      assert( p->iRangeEnd>=0 );
+      fts5HighlightAppend(&rc, p, p->zOpen, -1);
+      p->bOpen = 1;
+    }
+    fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iEndOff - p->iOff);
+    p->iOff = iEndOff;
+
+    if( rc==SQLITE_OK ){
+      rc = fts5CInstIterNext(&p->iter);
+    }
+  }
+
+  if( iPos==p->iRangeEnd ){
+    if( p->bOpen ){
+      if( p->iter.iStart>=0 && iPos>=p->iter.iStart ){
+        fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iEndOff - p->iOff);
+        p->iOff = iEndOff;
+      }
+      fts5HighlightAppend(&rc, p, p->zClose, -1);
+      p->bOpen = 0;
+    }
+    fts5HighlightAppend(&rc, p, &p->zIn[p->iOff], iEndOff - p->iOff);
+    p->iOff = iEndOff;
+  }
+
+  return rc;
+}
+
+
+/*
+** Implementation of highlight() function.
+*/
+static void fts5HighlightFunction(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+){
+  HighlightContext ctx;
+  int rc;
+  int iCol;
+
+  if( nVal!=3 ){
+    const char *zErr = "wrong number of arguments to function highlight()";
+    sqlite3_result_error(pCtx, zErr, -1);
+    return;
+  }
+
+  iCol = sqlite3_value_int(apVal[0]);
+  memset(&ctx, 0, sizeof(HighlightContext));
+  ctx.zOpen = (const char*)sqlite3_value_text(apVal[1]);
+  ctx.zClose = (const char*)sqlite3_value_text(apVal[2]);
+  ctx.iRangeEnd = -1;
+  rc = pApi->xColumnText(pFts, iCol, &ctx.zIn, &ctx.nIn);
+  if( rc==SQLITE_RANGE ){
+    sqlite3_result_text(pCtx, "", -1, SQLITE_STATIC);
+    rc = SQLITE_OK;
+  }else if( ctx.zIn ){
+    const char *pLoc = 0;         /* Locale of column iCol */
+    int nLoc = 0;                 /* Size of pLoc in bytes */
+    if( rc==SQLITE_OK ){
+      rc = fts5CInstIterInit(pApi, pFts, iCol, &ctx.iter);
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = pApi->xColumnLocale(pFts, iCol, &pLoc, &nLoc);
+    }
+    if( rc==SQLITE_OK ){
+      rc = pApi->xTokenize_v2(
+          pFts, ctx.zIn, ctx.nIn, pLoc, nLoc, (void*)&ctx, fts5HighlightCb
+      );
+    }
+    if( ctx.bOpen ){
+      fts5HighlightAppend(&rc, &ctx, ctx.zClose, -1);
+    }
+    fts5HighlightAppend(&rc, &ctx, &ctx.zIn[ctx.iOff], ctx.nIn - ctx.iOff);
+
+    if( rc==SQLITE_OK ){
+      sqlite3_result_text(pCtx, (const char*)ctx.zOut, -1, SQLITE_TRANSIENT);
+    }
+    sqlite3_free(ctx.zOut);
+  }
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+  }
+}
+/*
+** End of highlight() implementation.
+**************************************************************************/
+
+/*
+** Context object passed to the fts5SentenceFinderCb() function.
+*/
+typedef struct Fts5SFinder Fts5SFinder;
+struct Fts5SFinder {
+  int iPos;                       /* Current token position */
+  int nFirstAlloc;                /* Allocated size of aFirst[] */
+  int nFirst;                     /* Number of entries in aFirst[] */
+  int *aFirst;                    /* Array of first token in each sentence */
+  const char *zDoc;               /* Document being tokenized */
+};
+
+/*
+** Add an entry to the Fts5SFinder.aFirst[] array. Grow the array if
+** necessary. Return SQLITE_OK if successful, or SQLITE_NOMEM if an
+** error occurs.
+*/
+static int fts5SentenceFinderAdd(Fts5SFinder *p, int iAdd){
+  if( p->nFirstAlloc==p->nFirst ){
+    int nNew = p->nFirstAlloc ? p->nFirstAlloc*2 : 64;
+    int *aNew;
+
+    aNew = (int*)sqlite3_realloc64(p->aFirst, nNew*sizeof(int));
+    if( aNew==0 ) return SQLITE_NOMEM;
+    p->aFirst = aNew;
+    p->nFirstAlloc = nNew;
+  }
+  p->aFirst[p->nFirst++] = iAdd;
+  return SQLITE_OK;
+}
+
+/*
+** This function is an xTokenize() callback used by the auxiliary snippet()
+** function. Its job is to identify tokens that are the first in a sentence.
+** For each such token, an entry is added to the SFinder.aFirst[] array.
+*/
+static int fts5SentenceFinderCb(
+  void *pContext,                 /* Pointer to HighlightContext object */
+  int tflags,                     /* Mask of FTS5_TOKEN_* flags */
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iStartOff,                  /* Start offset of token */
+  int iEndOff                     /* End offset of token */
+){
+  int rc = SQLITE_OK;
+
+  UNUSED_PARAM2(pToken, nToken);
+  UNUSED_PARAM(iEndOff);
+
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 ){
+    Fts5SFinder *p = (Fts5SFinder*)pContext;
+    if( p->iPos>0 ){
+      int i;
+      char c = 0;
+      for(i=iStartOff-1; i>=0; i--){
+        c = p->zDoc[i];
+        if( c!=' ' && c!='\t' && c!='\n' && c!='\r' ) break;
+      }
+      if( i!=iStartOff-1 && (c=='.' || c==':') ){
+        rc = fts5SentenceFinderAdd(p, p->iPos);
+      }
+    }else{
+      rc = fts5SentenceFinderAdd(p, 0);
+    }
+    p->iPos++;
+  }
+  return rc;
+}
+
+static int fts5SnippetScore(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  int nDocsize,                   /* Size of column in tokens */
+  unsigned char *aSeen,           /* Array with one element per query phrase */
+  int iCol,                       /* Column to score */
+  int iPos,                       /* Starting offset to score */
+  int nToken,                     /* Max tokens per snippet */
+  int *pnScore,                   /* OUT: Score */
+  int *piPos                      /* OUT: Adjusted offset */
+){
+  int rc;
+  int i;
+  int ip = 0;
+  int ic = 0;
+  int iOff = 0;
+  int iFirst = -1;
+  int nInst;
+  int nScore = 0;
+  int iLast = 0;
+  sqlite3_int64 iEnd = (sqlite3_int64)iPos + nToken;
+
+  rc = pApi->xInstCount(pFts, &nInst);
+  for(i=0; i<nInst && rc==SQLITE_OK; i++){
+    rc = pApi->xInst(pFts, i, &ip, &ic, &iOff);
+    if( rc==SQLITE_OK && ic==iCol && iOff>=iPos && iOff<iEnd ){
+      nScore += (aSeen[ip] ? 1 : 1000);
+      aSeen[ip] = 1;
+      if( iFirst<0 ) iFirst = iOff;
+      iLast = iOff + pApi->xPhraseSize(pFts, ip);
+    }
+  }
+
+  *pnScore = nScore;
+  if( piPos ){
+    sqlite3_int64 iAdj = iFirst - (nToken - (iLast-iFirst)) / 2;
+    if( (iAdj+nToken)>nDocsize ) iAdj = nDocsize - nToken;
+    if( iAdj<0 ) iAdj = 0;
+    *piPos = (int)iAdj;
+  }
+
+  return rc;
+}
+
+/*
+** Return the value in pVal interpreted as utf-8 text. Except, if pVal
+** contains a NULL value, return a pointer to a static string zero
+** bytes in length instead of a NULL pointer.
+*/
+static const char *fts5ValueToText(sqlite3_value *pVal){
+  const char *zRet = (const char*)sqlite3_value_text(pVal);
+  return zRet ? zRet : "";
+}
+
+/*
+** Implementation of snippet() function.
+*/
+static void fts5SnippetFunction(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+){
+  HighlightContext ctx;
+  int rc = SQLITE_OK;             /* Return code */
+  int iCol;                       /* 1st argument to snippet() */
+  const char *zEllips;            /* 4th argument to snippet() */
+  int nToken;                     /* 5th argument to snippet() */
+  int nInst = 0;                  /* Number of instance matches this row */
+  int i;                          /* Used to iterate through instances */
+  int nPhrase;                    /* Number of phrases in query */
+  unsigned char *aSeen;           /* Array of "seen instance" flags */
+  int iBestCol;                   /* Column containing best snippet */
+  int iBestStart = 0;             /* First token of best snippet */
+  int nBestScore = 0;             /* Score of best snippet */
+  int nColSize = 0;               /* Total size of iBestCol in tokens */
+  Fts5SFinder sFinder;            /* Used to find the beginnings of sentences */
+  int nCol;
+
+  if( nVal!=5 ){
+    const char *zErr = "wrong number of arguments to function snippet()";
+    sqlite3_result_error(pCtx, zErr, -1);
+    return;
+  }
+
+  nCol = pApi->xColumnCount(pFts);
+  memset(&ctx, 0, sizeof(HighlightContext));
+  iCol = sqlite3_value_int(apVal[0]);
+  ctx.zOpen = fts5ValueToText(apVal[1]);
+  ctx.zClose = fts5ValueToText(apVal[2]);
+  ctx.iRangeEnd = -1;
+  zEllips = fts5ValueToText(apVal[3]);
+  nToken = sqlite3_value_int(apVal[4]);
+
+  iBestCol = (iCol>=0 ? iCol : 0);
+  nPhrase = pApi->xPhraseCount(pFts);
+  aSeen = sqlite3_malloc(nPhrase);
+  if( aSeen==0 ){
+    rc = SQLITE_NOMEM;
+  }
+  if( rc==SQLITE_OK ){
+    rc = pApi->xInstCount(pFts, &nInst);
+  }
+
+  memset(&sFinder, 0, sizeof(Fts5SFinder));
+  for(i=0; i<nCol; i++){
+    if( iCol<0 || iCol==i ){
+      const char *pLoc = 0;       /* Locale of column iCol */
+      int nLoc = 0;               /* Size of pLoc in bytes */
+      int nDoc;
+      int nDocsize;
+      int ii;
+      sFinder.iPos = 0;
+      sFinder.nFirst = 0;
+      rc = pApi->xColumnText(pFts, i, &sFinder.zDoc, &nDoc);
+      if( rc!=SQLITE_OK ) break;
+      rc = pApi->xColumnLocale(pFts, i, &pLoc, &nLoc);
+      if( rc!=SQLITE_OK ) break;
+      rc = pApi->xTokenize_v2(pFts,
+          sFinder.zDoc, nDoc, pLoc, nLoc, (void*)&sFinder, fts5SentenceFinderCb
+      );
+      if( rc!=SQLITE_OK ) break;
+      rc = pApi->xColumnSize(pFts, i, &nDocsize);
+      if( rc!=SQLITE_OK ) break;
+
+      for(ii=0; rc==SQLITE_OK && ii<nInst; ii++){
+        int ip, ic, io;
+        int iAdj;
+        int nScore;
+        int jj;
+
+        rc = pApi->xInst(pFts, ii, &ip, &ic, &io);
+        if( ic!=i ) continue;
+        if( io>nDocsize ) rc = FTS5_CORRUPT;
+        if( rc!=SQLITE_OK ) continue;
+        memset(aSeen, 0, nPhrase);
+        rc = fts5SnippetScore(pApi, pFts, nDocsize, aSeen, i,
+            io, nToken, &nScore, &iAdj
+        );
+        if( rc==SQLITE_OK && nScore>nBestScore ){
+          nBestScore = nScore;
+          iBestCol = i;
+          iBestStart = iAdj;
+          nColSize = nDocsize;
+        }
+
+        if( rc==SQLITE_OK && sFinder.nFirst && nDocsize>nToken ){
+          for(jj=0; jj<(sFinder.nFirst-1); jj++){
+            if( sFinder.aFirst[jj+1]>io ) break;
+          }
+
+          if( sFinder.aFirst[jj]<io ){
+            memset(aSeen, 0, nPhrase);
+            rc = fts5SnippetScore(pApi, pFts, nDocsize, aSeen, i,
+              sFinder.aFirst[jj], nToken, &nScore, 0
+            );
+
+            nScore += (sFinder.aFirst[jj]==0 ? 120 : 100);
+            if( rc==SQLITE_OK && nScore>nBestScore ){
+              nBestScore = nScore;
+              iBestCol = i;
+              iBestStart = sFinder.aFirst[jj];
+              nColSize = nDocsize;
+            }
+          }
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = pApi->xColumnText(pFts, iBestCol, &ctx.zIn, &ctx.nIn);
+  }
+  if( rc==SQLITE_OK && nColSize==0 ){
+    rc = pApi->xColumnSize(pFts, iBestCol, &nColSize);
+  }
+  if( ctx.zIn ){
+    const char *pLoc = 0;         /* Locale of column iBestCol */
+    int nLoc = 0;                 /* Bytes in pLoc */
+
+    if( rc==SQLITE_OK ){
+      rc = fts5CInstIterInit(pApi, pFts, iBestCol, &ctx.iter);
+    }
+
+    ctx.iRangeStart = iBestStart;
+    ctx.iRangeEnd = iBestStart + nToken - 1;
+
+    if( iBestStart>0 ){
+      fts5HighlightAppend(&rc, &ctx, zEllips, -1);
+    }
+
+    /* Advance iterator ctx.iter so that it points to the first coalesced
+    ** phrase instance at or following position iBestStart. */
+    while( ctx.iter.iStart>=0 && ctx.iter.iStart<iBestStart && rc==SQLITE_OK ){
+      rc = fts5CInstIterNext(&ctx.iter);
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = pApi->xColumnLocale(pFts, iBestCol, &pLoc, &nLoc);
+    }
+    if( rc==SQLITE_OK ){
+      rc = pApi->xTokenize_v2(
+          pFts, ctx.zIn, ctx.nIn, pLoc, nLoc, (void*)&ctx,fts5HighlightCb
+      );
+    }
+    if( ctx.bOpen ){
+      fts5HighlightAppend(&rc, &ctx, ctx.zClose, -1);
+    }
+    if( ctx.iRangeEnd>=(nColSize-1) ){
+      fts5HighlightAppend(&rc, &ctx, &ctx.zIn[ctx.iOff], ctx.nIn - ctx.iOff);
+    }else{
+      fts5HighlightAppend(&rc, &ctx, zEllips, -1);
+    }
+  }
+  if( rc==SQLITE_OK ){
+    sqlite3_result_text(pCtx, (const char*)ctx.zOut, -1, SQLITE_TRANSIENT);
+  }else{
+    sqlite3_result_error_code(pCtx, rc);
+  }
+  sqlite3_free(ctx.zOut);
+  sqlite3_free(aSeen);
+  sqlite3_free(sFinder.aFirst);
+}
+
+/************************************************************************/
+
+/*
+** The first time the bm25() function is called for a query, an instance
+** of the following structure is allocated and populated.
+*/
+typedef struct Fts5Bm25Data Fts5Bm25Data;
+struct Fts5Bm25Data {
+  int nPhrase;                    /* Number of phrases in query */
+  double avgdl;                   /* Average number of tokens in each row */
+  double *aIDF;                   /* IDF for each phrase */
+  double *aFreq;                  /* Array used to calculate phrase freq. */
+};
+
+/*
+** Callback used by fts5Bm25GetData() to count the number of rows in the
+** table matched by each individual phrase within the query.
+*/
+static int fts5CountCb(
+  const Fts5ExtensionApi *pApi,
+  Fts5Context *pFts,
+  void *pUserData                 /* Pointer to sqlite3_int64 variable */
+){
+  sqlite3_int64 *pn = (sqlite3_int64*)pUserData;
+  UNUSED_PARAM2(pApi, pFts);
+  (*pn)++;
+  return SQLITE_OK;
+}
+
+/*
+** Set *ppData to point to the Fts5Bm25Data object for the current query.
+** If the object has not already been allocated, allocate and populate it
+** now.
+*/
+static int fts5Bm25GetData(
+  const Fts5ExtensionApi *pApi,
+  Fts5Context *pFts,
+  Fts5Bm25Data **ppData           /* OUT: bm25-data object for this query */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5Bm25Data *p;                /* Object to return */
+
+  p = (Fts5Bm25Data*)pApi->xGetAuxdata(pFts, 0);
+  if( p==0 ){
+    int nPhrase;                  /* Number of phrases in query */
+    sqlite3_int64 nRow = 0;       /* Number of rows in table */
+    sqlite3_int64 nToken = 0;     /* Number of tokens in table */
+    sqlite3_int64 nByte;          /* Bytes of space to allocate */
+    int i;
+
+    /* Allocate the Fts5Bm25Data object */
+    nPhrase = pApi->xPhraseCount(pFts);
+    nByte = sizeof(Fts5Bm25Data) + nPhrase*2*sizeof(double);
+    p = (Fts5Bm25Data*)sqlite3_malloc64(nByte);
+    if( p==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(p, 0, (size_t)nByte);
+      p->nPhrase = nPhrase;
+      p->aIDF = (double*)&p[1];
+      p->aFreq = &p->aIDF[nPhrase];
+    }
+
+    /* Calculate the average document length for this FTS5 table */
+    if( rc==SQLITE_OK ) rc = pApi->xRowCount(pFts, &nRow);
+    assert( rc!=SQLITE_OK || nRow>0 );
+    if( rc==SQLITE_OK ) rc = pApi->xColumnTotalSize(pFts, -1, &nToken);
+    if( rc==SQLITE_OK ) p->avgdl = (double)nToken  / (double)nRow;
+
+    /* Calculate an IDF for each phrase in the query */
+    for(i=0; rc==SQLITE_OK && i<nPhrase; i++){
+      sqlite3_int64 nHit = 0;
+      rc = pApi->xQueryPhrase(pFts, i, (void*)&nHit, fts5CountCb);
+      if( rc==SQLITE_OK ){
+        /* Calculate the IDF (Inverse Document Frequency) for phrase i.
+        ** This is done using the standard BM25 formula as found on wikipedia:
+        **
+        **   IDF = log( (N - nHit + 0.5) / (nHit + 0.5) )
+        **
+        ** where "N" is the total number of documents in the set and nHit
+        ** is the number that contain at least one instance of the phrase
+        ** under consideration.
+        **
+        ** The problem with this is that if (N < 2*nHit), the IDF is
+        ** negative. Which is undesirable. So the mimimum allowable IDF is
+        ** (1e-6) - roughly the same as a term that appears in just over
+        ** half of set of 5,000,000 documents.  */
+        double idf = log( (nRow - nHit + 0.5) / (nHit + 0.5) );
+        if( idf<=0.0 ) idf = 1e-6;
+        p->aIDF[i] = idf;
+      }
+    }
+
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(p);
+    }else{
+      rc = pApi->xSetAuxdata(pFts, p, sqlite3_free);
+    }
+    if( rc!=SQLITE_OK ) p = 0;
+  }
+  *ppData = p;
+  return rc;
+}
+
+/*
+** Implementation of bm25() function.
+*/
+static void fts5Bm25Function(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+){
+  const double k1 = 1.2;          /* Constant "k1" from BM25 formula */
+  const double b = 0.75;          /* Constant "b" from BM25 formula */
+  int rc;                         /* Error code */
+  double score = 0.0;             /* SQL function return value */
+  Fts5Bm25Data *pData;            /* Values allocated/calculated once only */
+  int i;                          /* Iterator variable */
+  int nInst = 0;                  /* Value returned by xInstCount() */
+  double D = 0.0;                 /* Total number of tokens in row */
+  double *aFreq = 0;              /* Array of phrase freq. for current row */
+
+  /* Calculate the phrase frequency (symbol "f(qi,D)" in the documentation)
+  ** for each phrase in the query for the current row. */
+  rc = fts5Bm25GetData(pApi, pFts, &pData);
+  if( rc==SQLITE_OK ){
+    aFreq = pData->aFreq;
+    memset(aFreq, 0, sizeof(double) * pData->nPhrase);
+    rc = pApi->xInstCount(pFts, &nInst);
+  }
+  for(i=0; rc==SQLITE_OK && i<nInst; i++){
+    int ip; int ic; int io;
+    rc = pApi->xInst(pFts, i, &ip, &ic, &io);
+    if( rc==SQLITE_OK ){
+      double w = (nVal > ic) ? sqlite3_value_double(apVal[ic]) : 1.0;
+      aFreq[ip] += w;
+    }
+  }
+
+  /* Figure out the total size of the current row in tokens. */
+  if( rc==SQLITE_OK ){
+    int nTok;
+    rc = pApi->xColumnSize(pFts, -1, &nTok);
+    D = (double)nTok;
+  }
+
+  /* Determine and return the BM25 score for the current row. Or, if an
+  ** error has occurred, throw an exception. */
+  if( rc==SQLITE_OK ){
+    for(i=0; i<pData->nPhrase; i++){
+      score += pData->aIDF[i] * (
+          ( aFreq[i] * (k1 + 1.0) ) /
+          ( aFreq[i] + k1 * (1 - b + b * D / pData->avgdl) )
+      );
+    }
+    sqlite3_result_double(pCtx, -1.0 * score);
+  }else{
+    sqlite3_result_error_code(pCtx, rc);
+  }
+}
+
+/*
+** Implementation of fts5_get_locale() function.
+*/
+static void fts5GetLocaleFunction(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+){
+  int iCol = 0;
+  int eType = 0;
+  int rc = SQLITE_OK;
+  const char *zLocale = 0;
+  int nLocale = 0;
+
+  /* xColumnLocale() must be available */
+  assert( pApi->iVersion>=4 );
+
+  if( nVal!=1 ){
+    const char *z = "wrong number of arguments to function fts5_get_locale()";
+    sqlite3_result_error(pCtx, z, -1);
+    return;
+  }
+
+  eType = sqlite3_value_numeric_type(apVal[0]);
+  if( eType!=SQLITE_INTEGER ){
+    const char *z = "non-integer argument passed to function fts5_get_locale()";
+    sqlite3_result_error(pCtx, z, -1);
+    return;
+  }
+
+  iCol = sqlite3_value_int(apVal[0]);
+  if( iCol<0 || iCol>=pApi->xColumnCount(pFts) ){
+    sqlite3_result_error_code(pCtx, SQLITE_RANGE);
+    return;
+  }
+
+  rc = pApi->xColumnLocale(pFts, iCol, &zLocale, &nLocale);
+  if( rc!=SQLITE_OK ){
+    sqlite3_result_error_code(pCtx, rc);
+    return;
+  }
+
+  sqlite3_result_text(pCtx, zLocale, nLocale, SQLITE_TRANSIENT);
+}
+
+static int sqlite3Fts5AuxInit(fts5_api *pApi){
+  struct Builtin {
+    const char *zFunc;            /* Function name (nul-terminated) */
+    void *pUserData;              /* User-data pointer */
+    fts5_extension_function xFunc;/* Callback function */
+    void (*xDestroy)(void*);      /* Destructor function */
+  } aBuiltin [] = {
+    { "snippet",         0, fts5SnippetFunction,   0 },
+    { "highlight",       0, fts5HighlightFunction, 0 },
+    { "bm25",            0, fts5Bm25Function,      0 },
+    { "fts5_get_locale", 0, fts5GetLocaleFunction, 0 },
+  };
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* To iterate through builtin functions */
+
+  for(i=0; rc==SQLITE_OK && i<ArraySize(aBuiltin); i++){
+    rc = pApi->xCreateFunction(pApi,
+        aBuiltin[i].zFunc,
+        aBuiltin[i].pUserData,
+        aBuiltin[i].xFunc,
+        aBuiltin[i].xDestroy
+    );
+  }
+
+  return rc;
+}
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+
+
+/* #include "fts5Int.h" */
+
+static int sqlite3Fts5BufferSize(int *pRc, Fts5Buffer *pBuf, u32 nByte){
+  if( (u32)pBuf->nSpace<nByte ){
+    u64 nNew = pBuf->nSpace ? pBuf->nSpace : 64;
+    u8 *pNew;
+    while( nNew<nByte ){
+      nNew = nNew * 2;
+    }
+    pNew = sqlite3_realloc64(pBuf->p, nNew);
+    if( pNew==0 ){
+      *pRc = SQLITE_NOMEM;
+      return 1;
+    }else{
+      pBuf->nSpace = (int)nNew;
+      pBuf->p = pNew;
+    }
+  }
+  return 0;
+}
+
+
+/*
+** Encode value iVal as an SQLite varint and append it to the buffer object
+** pBuf. If an OOM error occurs, set the error code in p.
+*/
+static void sqlite3Fts5BufferAppendVarint(int *pRc, Fts5Buffer *pBuf, i64 iVal){
+  if( fts5BufferGrow(pRc, pBuf, 9) ) return;
+  pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], iVal);
+}
+
+static void sqlite3Fts5Put32(u8 *aBuf, int iVal){
+  aBuf[0] = (iVal>>24) & 0x00FF;
+  aBuf[1] = (iVal>>16) & 0x00FF;
+  aBuf[2] = (iVal>> 8) & 0x00FF;
+  aBuf[3] = (iVal>> 0) & 0x00FF;
+}
+
+static int sqlite3Fts5Get32(const u8 *aBuf){
+  return (int)((((u32)aBuf[0])<<24) + (aBuf[1]<<16) + (aBuf[2]<<8) + aBuf[3]);
+}
+
+/*
+** Append buffer nData/pData to buffer pBuf. If an OOM error occurs, set
+** the error code in p. If an error has already occurred when this function
+** is called, it is a no-op.
+*/
+static void sqlite3Fts5BufferAppendBlob(
+  int *pRc,
+  Fts5Buffer *pBuf,
+  u32 nData,
+  const u8 *pData
+){
+  if( nData ){
+    if( fts5BufferGrow(pRc, pBuf, nData) ) return;
+    assert( pBuf->p!=0 );
+    memcpy(&pBuf->p[pBuf->n], pData, nData);
+    pBuf->n += nData;
+  }
+}
+
+/*
+** Append the nul-terminated string zStr to the buffer pBuf. This function
+** ensures that the byte following the buffer data is set to 0x00, even
+** though this byte is not included in the pBuf->n count.
+*/
+static void sqlite3Fts5BufferAppendString(
+  int *pRc,
+  Fts5Buffer *pBuf,
+  const char *zStr
+){
+  int nStr = (int)strlen(zStr);
+  sqlite3Fts5BufferAppendBlob(pRc, pBuf, nStr+1, (const u8*)zStr);
+  pBuf->n--;
+}
+
+/*
+** Argument zFmt is a printf() style format string. This function performs
+** the printf() style processing, then appends the results to buffer pBuf.
+**
+** Like sqlite3Fts5BufferAppendString(), this function ensures that the byte
+** following the buffer data is set to 0x00, even though this byte is not
+** included in the pBuf->n count.
+*/
+static void sqlite3Fts5BufferAppendPrintf(
+  int *pRc,
+  Fts5Buffer *pBuf,
+  char *zFmt, ...
+){
+  if( *pRc==SQLITE_OK ){
+    char *zTmp;
+    va_list ap;
+    va_start(ap, zFmt);
+    zTmp = sqlite3_vmprintf(zFmt, ap);
+    va_end(ap);
+
+    if( zTmp==0 ){
+      *pRc = SQLITE_NOMEM;
+    }else{
+      sqlite3Fts5BufferAppendString(pRc, pBuf, zTmp);
+      sqlite3_free(zTmp);
+    }
+  }
+}
+
+static char *sqlite3Fts5Mprintf(int *pRc, const char *zFmt, ...){
+  char *zRet = 0;
+  if( *pRc==SQLITE_OK ){
+    va_list ap;
+    va_start(ap, zFmt);
+    zRet = sqlite3_vmprintf(zFmt, ap);
+    va_end(ap);
+    if( zRet==0 ){
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+  return zRet;
+}
+
+
+/*
+** Free any buffer allocated by pBuf. Zero the structure before returning.
+*/
+static void sqlite3Fts5BufferFree(Fts5Buffer *pBuf){
+  sqlite3_free(pBuf->p);
+  memset(pBuf, 0, sizeof(Fts5Buffer));
+}
+
+/*
+** Zero the contents of the buffer object. But do not free the associated
+** memory allocation.
+*/
+static void sqlite3Fts5BufferZero(Fts5Buffer *pBuf){
+  pBuf->n = 0;
+}
+
+/*
+** Set the buffer to contain nData/pData. If an OOM error occurs, leave an
+** the error code in p. If an error has already occurred when this function
+** is called, it is a no-op.
+*/
+static void sqlite3Fts5BufferSet(
+  int *pRc,
+  Fts5Buffer *pBuf,
+  int nData,
+  const u8 *pData
+){
+  pBuf->n = 0;
+  sqlite3Fts5BufferAppendBlob(pRc, pBuf, nData, pData);
+}
+
+static int sqlite3Fts5PoslistNext64(
+  const u8 *a, int n,             /* Buffer containing poslist */
+  int *pi,                        /* IN/OUT: Offset within a[] */
+  i64 *piOff                      /* IN/OUT: Current offset */
+){
+  int i = *pi;
+  assert( a!=0 || i==0 );
+  if( i>=n ){
+    /* EOF */
+    *piOff = -1;
+    return 1;
+  }else{
+    i64 iOff = *piOff;
+    u32 iVal;
+    assert( a!=0 );
+    fts5FastGetVarint32(a, i, iVal);
+    if( iVal<=1 ){
+      if( iVal==0 ){
+        *pi = i;
+        return 0;
+      }
+      fts5FastGetVarint32(a, i, iVal);
+      iOff = ((i64)iVal) << 32;
+      assert( iOff>=0 );
+      fts5FastGetVarint32(a, i, iVal);
+      if( iVal<2 ){
+        /* This is a corrupt record. So stop parsing it here. */
+        *piOff = -1;
+        return 1;
+      }
+      *piOff = iOff + ((iVal-2) & 0x7FFFFFFF);
+    }else{
+      *piOff = (iOff & (i64)0x7FFFFFFF<<32)+((iOff + (iVal-2)) & 0x7FFFFFFF);
+    }
+    *pi = i;
+    assert_nc( *piOff>=iOff );
+    return 0;
+  }
+}
+
+
+/*
+** Advance the iterator object passed as the only argument. Return true
+** if the iterator reaches EOF, or false otherwise.
+*/
+static int sqlite3Fts5PoslistReaderNext(Fts5PoslistReader *pIter){
+  if( sqlite3Fts5PoslistNext64(pIter->a, pIter->n, &pIter->i, &pIter->iPos) ){
+    pIter->bEof = 1;
+  }
+  return pIter->bEof;
+}
+
+static int sqlite3Fts5PoslistReaderInit(
+  const u8 *a, int n,             /* Poslist buffer to iterate through */
+  Fts5PoslistReader *pIter        /* Iterator object to initialize */
+){
+  memset(pIter, 0, sizeof(*pIter));
+  pIter->a = a;
+  pIter->n = n;
+  sqlite3Fts5PoslistReaderNext(pIter);
+  return pIter->bEof;
+}
+
+/*
+** Append position iPos to the position list being accumulated in buffer
+** pBuf, which must be already be large enough to hold the new data.
+** The previous position written to this list is *piPrev. *piPrev is set
+** to iPos before returning.
+*/
+static void sqlite3Fts5PoslistSafeAppend(
+  Fts5Buffer *pBuf,
+  i64 *piPrev,
+  i64 iPos
+){
+  if( iPos>=*piPrev ){
+    static const i64 colmask = ((i64)(0x7FFFFFFF)) << 32;
+    if( (iPos & colmask) != (*piPrev & colmask) ){
+      pBuf->p[pBuf->n++] = 1;
+      pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], (iPos>>32));
+      *piPrev = (iPos & colmask);
+    }
+    pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], (iPos-*piPrev)+2);
+    *piPrev = iPos;
+  }
+}
+
+static int sqlite3Fts5PoslistWriterAppend(
+  Fts5Buffer *pBuf,
+  Fts5PoslistWriter *pWriter,
+  i64 iPos
+){
+  int rc = 0;   /* Initialized only to suppress erroneous warning from Clang */
+  if( fts5BufferGrow(&rc, pBuf, 5+5+5) ) return rc;
+  sqlite3Fts5PoslistSafeAppend(pBuf, &pWriter->iPrev, iPos);
+  return SQLITE_OK;
+}
+
+static void *sqlite3Fts5MallocZero(int *pRc, sqlite3_int64 nByte){
+  void *pRet = 0;
+  if( *pRc==SQLITE_OK ){
+    pRet = sqlite3_malloc64(nByte);
+    if( pRet==0 ){
+      if( nByte>0 ) *pRc = SQLITE_NOMEM;
+    }else{
+      memset(pRet, 0, (size_t)nByte);
+    }
+  }
+  return pRet;
+}
+
+/*
+** Return a nul-terminated copy of the string indicated by pIn. If nIn
+** is non-negative, then it is the length of the string in bytes. Otherwise,
+** the length of the string is determined using strlen().
+**
+** It is the responsibility of the caller to eventually free the returned
+** buffer using sqlite3_free(). If an OOM error occurs, NULL is returned.
+*/
+static char *sqlite3Fts5Strndup(int *pRc, const char *pIn, int nIn){
+  char *zRet = 0;
+  if( *pRc==SQLITE_OK ){
+    if( nIn<0 ){
+      nIn = (int)strlen(pIn);
+    }
+    zRet = (char*)sqlite3_malloc(nIn+1);
+    if( zRet ){
+      memcpy(zRet, pIn, nIn);
+      zRet[nIn] = '\0';
+    }else{
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+  return zRet;
+}
+
+
+/*
+** Return true if character 't' may be part of an FTS5 bareword, or false
+** otherwise. Characters that may be part of barewords:
+**
+**   * All non-ASCII characters,
+**   * The 52 upper and lower case ASCII characters, and
+**   * The 10 integer ASCII characters.
+**   * The underscore character "_" (0x5F).
+**   * The unicode "subsitute" character (0x1A).
+*/
+static int sqlite3Fts5IsBareword(char t){
+  u8 aBareword[128] = {
+    0, 0, 0, 0, 0, 0, 0, 0,    0, 0, 0, 0, 0, 0, 0, 0,   /* 0x00 .. 0x0F */
+    0, 0, 0, 0, 0, 0, 0, 0,    0, 0, 1, 0, 0, 0, 0, 0,   /* 0x10 .. 0x1F */
+    0, 0, 0, 0, 0, 0, 0, 0,    0, 0, 0, 0, 0, 0, 0, 0,   /* 0x20 .. 0x2F */
+    1, 1, 1, 1, 1, 1, 1, 1,    1, 1, 0, 0, 0, 0, 0, 0,   /* 0x30 .. 0x3F */
+    0, 1, 1, 1, 1, 1, 1, 1,    1, 1, 1, 1, 1, 1, 1, 1,   /* 0x40 .. 0x4F */
+    1, 1, 1, 1, 1, 1, 1, 1,    1, 1, 1, 0, 0, 0, 0, 1,   /* 0x50 .. 0x5F */
+    0, 1, 1, 1, 1, 1, 1, 1,    1, 1, 1, 1, 1, 1, 1, 1,   /* 0x60 .. 0x6F */
+    1, 1, 1, 1, 1, 1, 1, 1,    1, 1, 1, 0, 0, 0, 0, 0    /* 0x70 .. 0x7F */
+  };
+
+  return (t & 0x80) || aBareword[(int)t];
+}
+
+
+/*************************************************************************
+*/
+typedef struct Fts5TermsetEntry Fts5TermsetEntry;
+struct Fts5TermsetEntry {
+  char *pTerm;
+  int nTerm;
+  int iIdx;                       /* Index (main or aPrefix[] entry) */
+  Fts5TermsetEntry *pNext;
+};
+
+struct Fts5Termset {
+  Fts5TermsetEntry *apHash[512];
+};
+
+static int sqlite3Fts5TermsetNew(Fts5Termset **pp){
+  int rc = SQLITE_OK;
+  *pp = sqlite3Fts5MallocZero(&rc, sizeof(Fts5Termset));
+  return rc;
+}
+
+static int sqlite3Fts5TermsetAdd(
+  Fts5Termset *p,
+  int iIdx,
+  const char *pTerm, int nTerm,
+  int *pbPresent
+){
+  int rc = SQLITE_OK;
+  *pbPresent = 0;
+  if( p ){
+    int i;
+    u32 hash = 13;
+    Fts5TermsetEntry *pEntry;
+
+    /* Calculate a hash value for this term. This is the same hash checksum
+    ** used by the fts5_hash.c module. This is not important for correct
+    ** operation of the module, but is necessary to ensure that some tests
+    ** designed to produce hash table collisions really do work.  */
+    for(i=nTerm-1; i>=0; i--){
+      hash = (hash << 3) ^ hash ^ pTerm[i];
+    }
+    hash = (hash << 3) ^ hash ^ iIdx;
+    hash = hash % ArraySize(p->apHash);
+
+    for(pEntry=p->apHash[hash]; pEntry; pEntry=pEntry->pNext){
+      if( pEntry->iIdx==iIdx
+          && pEntry->nTerm==nTerm
+          && memcmp(pEntry->pTerm, pTerm, nTerm)==0
+      ){
+        *pbPresent = 1;
+        break;
+      }
+    }
+
+    if( pEntry==0 ){
+      pEntry = sqlite3Fts5MallocZero(&rc, sizeof(Fts5TermsetEntry) + nTerm);
+      if( pEntry ){
+        pEntry->pTerm = (char*)&pEntry[1];
+        pEntry->nTerm = nTerm;
+        pEntry->iIdx = iIdx;
+        memcpy(pEntry->pTerm, pTerm, nTerm);
+        pEntry->pNext = p->apHash[hash];
+        p->apHash[hash] = pEntry;
+      }
+    }
+  }
+
+  return rc;
+}
+
+static void sqlite3Fts5TermsetFree(Fts5Termset *p){
+  if( p ){
+    u32 i;
+    for(i=0; i<ArraySize(p->apHash); i++){
+      Fts5TermsetEntry *pEntry = p->apHash[i];
+      while( pEntry ){
+        Fts5TermsetEntry *pDel = pEntry;
+        pEntry = pEntry->pNext;
+        sqlite3_free(pDel);
+      }
+    }
+    sqlite3_free(p);
+  }
+}
+
+/*
+** 2014 Jun 09
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is an SQLite module implementing full-text search.
+*/
+
+
+/* #include "fts5Int.h" */
+
+#define FTS5_DEFAULT_PAGE_SIZE   4050
+#define FTS5_DEFAULT_AUTOMERGE      4
+#define FTS5_DEFAULT_USERMERGE      4
+#define FTS5_DEFAULT_CRISISMERGE   16
+#define FTS5_DEFAULT_HASHSIZE    (1024*1024)
+
+#define FTS5_DEFAULT_DELETE_AUTOMERGE 10      /* default 10% */
+
+/* Maximum allowed page size */
+#define FTS5_MAX_PAGE_SIZE (64*1024)
+
+static int fts5_iswhitespace(char x){
+  return (x==' ');
+}
+
+static int fts5_isopenquote(char x){
+  return (x=='"' || x=='\'' || x=='[' || x=='`');
+}
+
+/*
+** Argument pIn points to a character that is part of a nul-terminated
+** string. Return a pointer to the first character following *pIn in
+** the string that is not a white-space character.
+*/
+static const char *fts5ConfigSkipWhitespace(const char *pIn){
+  const char *p = pIn;
+  if( p ){
+    while( fts5_iswhitespace(*p) ){ p++; }
+  }
+  return p;
+}
+
+/*
+** Argument pIn points to a character that is part of a nul-terminated
+** string. Return a pointer to the first character following *pIn in
+** the string that is not a "bareword" character.
+*/
+static const char *fts5ConfigSkipBareword(const char *pIn){
+  const char *p = pIn;
+  while ( sqlite3Fts5IsBareword(*p) ) p++;
+  if( p==pIn ) p = 0;
+  return p;
+}
+
+static int fts5_isdigit(char a){
+  return (a>='0' && a<='9');
+}
+
+
+
+static const char *fts5ConfigSkipLiteral(const char *pIn){
+  const char *p = pIn;
+  switch( *p ){
+    case 'n': case 'N':
+      if( sqlite3_strnicmp("null", p, 4)==0 ){
+        p = &p[4];
+      }else{
+        p = 0;
+      }
+      break;
+
+    case 'x': case 'X':
+      p++;
+      if( *p=='\'' ){
+        p++;
+        while( (*p>='a' && *p<='f')
+            || (*p>='A' && *p<='F')
+            || (*p>='0' && *p<='9')
+            ){
+          p++;
+        }
+        if( *p=='\'' && 0==((p-pIn)%2) ){
+          p++;
+        }else{
+          p = 0;
+        }
+      }else{
+        p = 0;
+      }
+      break;
+
+    case '\'':
+      p++;
+      while( p ){
+        if( *p=='\'' ){
+          p++;
+          if( *p!='\'' ) break;
+        }
+        p++;
+        if( *p==0 ) p = 0;
+      }
+      break;
+
+    default:
+      /* maybe a number */
+      if( *p=='+' || *p=='-' ) p++;
+      while( fts5_isdigit(*p) ) p++;
+
+      /* At this point, if the literal was an integer, the parse is
+      ** finished. Or, if it is a floating point value, it may continue
+      ** with either a decimal point or an 'E' character. */
+      if( *p=='.' && fts5_isdigit(p[1]) ){
+        p += 2;
+        while( fts5_isdigit(*p) ) p++;
+      }
+      if( p==pIn ) p = 0;
+
+      break;
+  }
+
+  return p;
+}
+
+/*
+** The first character of the string pointed to by argument z is guaranteed
+** to be an open-quote character (see function fts5_isopenquote()).
+**
+** This function searches for the corresponding close-quote character within
+** the string and, if found, dequotes the string in place and adds a new
+** nul-terminator byte.
+**
+** If the close-quote is found, the value returned is the byte offset of
+** the character immediately following it. Or, if the close-quote is not
+** found, -1 is returned. If -1 is returned, the buffer is left in an
+** undefined state.
+*/
+static int fts5Dequote(char *z){
+  char q;
+  int iIn = 1;
+  int iOut = 0;
+  q = z[0];
+
+  /* Set stack variable q to the close-quote character */
+  assert( q=='[' || q=='\'' || q=='"' || q=='`' );
+  if( q=='[' ) q = ']';
+
+  while( z[iIn] ){
+    if( z[iIn]==q ){
+      if( z[iIn+1]!=q ){
+        /* Character iIn was the close quote. */
+        iIn++;
+        break;
+      }else{
+        /* Character iIn and iIn+1 form an escaped quote character. Skip
+        ** the input cursor past both and copy a single quote character
+        ** to the output buffer. */
+        iIn += 2;
+        z[iOut++] = q;
+      }
+    }else{
+      z[iOut++] = z[iIn++];
+    }
+  }
+
+  z[iOut] = '\0';
+  return iIn;
+}
+
+/*
+** Convert an SQL-style quoted string into a normal string by removing
+** the quote characters.  The conversion is done in-place.  If the
+** input does not begin with a quote character, then this routine
+** is a no-op.
+**
+** Examples:
+**
+**     "abc"   becomes   abc
+**     'xyz'   becomes   xyz
+**     [pqr]   becomes   pqr
+**     `mno`   becomes   mno
+*/
+static void sqlite3Fts5Dequote(char *z){
+  char quote;                     /* Quote character (if any ) */
+
+  assert( 0==fts5_iswhitespace(z[0]) );
+  quote = z[0];
+  if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){
+    fts5Dequote(z);
+  }
+}
+
+
+struct Fts5Enum {
+  const char *zName;
+  int eVal;
+};
+typedef struct Fts5Enum Fts5Enum;
+
+static int fts5ConfigSetEnum(
+  const Fts5Enum *aEnum,
+  const char *zEnum,
+  int *peVal
+){
+  int nEnum = (int)strlen(zEnum);
+  int i;
+  int iVal = -1;
+
+  for(i=0; aEnum[i].zName; i++){
+    if( sqlite3_strnicmp(aEnum[i].zName, zEnum, nEnum)==0 ){
+      if( iVal>=0 ) return SQLITE_ERROR;
+      iVal = aEnum[i].eVal;
+    }
+  }
+
+  *peVal = iVal;
+  return iVal<0 ? SQLITE_ERROR : SQLITE_OK;
+}
+
+/*
+** Parse a "special" CREATE VIRTUAL TABLE directive and update
+** configuration object pConfig as appropriate.
+**
+** If successful, object pConfig is updated and SQLITE_OK returned. If
+** an error occurs, an SQLite error code is returned and an error message
+** may be left in *pzErr. It is the responsibility of the caller to
+** eventually free any such error message using sqlite3_free().
+*/
+static int fts5ConfigParseSpecial(
+  Fts5Config *pConfig,            /* Configuration object to update */
+  const char *zCmd,               /* Special command to parse */
+  const char *zArg,               /* Argument to parse */
+  char **pzErr                    /* OUT: Error message */
+){
+  int rc = SQLITE_OK;
+  int nCmd = (int)strlen(zCmd);
+
+  if( sqlite3_strnicmp("prefix", zCmd, nCmd)==0 ){
+    const int nByte = sizeof(int) * FTS5_MAX_PREFIX_INDEXES;
+    const char *p;
+    int bFirst = 1;
+    if( pConfig->aPrefix==0 ){
+      pConfig->aPrefix = sqlite3Fts5MallocZero(&rc, nByte);
+      if( rc ) return rc;
+    }
+
+    p = zArg;
+    while( 1 ){
+      int nPre = 0;
+
+      while( p[0]==' ' ) p++;
+      if( bFirst==0 && p[0]==',' ){
+        p++;
+        while( p[0]==' ' ) p++;
+      }else if( p[0]=='\0' ){
+        break;
+      }
+      if( p[0]<'0' || p[0]>'9' ){
+        *pzErr = sqlite3_mprintf("malformed prefix=... directive");
+        rc = SQLITE_ERROR;
+        break;
+      }
+
+      if( pConfig->nPrefix==FTS5_MAX_PREFIX_INDEXES ){
+        *pzErr = sqlite3_mprintf(
+            "too many prefix indexes (max %d)", FTS5_MAX_PREFIX_INDEXES
+        );
+        rc = SQLITE_ERROR;
+        break;
+      }
+
+      while( p[0]>='0' && p[0]<='9' && nPre<1000 ){
+        nPre = nPre*10 + (p[0] - '0');
+        p++;
+      }
+
+      if( nPre<=0 || nPre>=1000 ){
+        *pzErr = sqlite3_mprintf("prefix length out of range (max 999)");
+        rc = SQLITE_ERROR;
+        break;
+      }
+
+      pConfig->aPrefix[pConfig->nPrefix] = nPre;
+      pConfig->nPrefix++;
+      bFirst = 0;
+    }
+    assert( pConfig->nPrefix<=FTS5_MAX_PREFIX_INDEXES );
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("tokenize", zCmd, nCmd)==0 ){
+    const char *p = (const char*)zArg;
+    sqlite3_int64 nArg = strlen(zArg) + 1;
+    char **azArg = sqlite3Fts5MallocZero(&rc, (sizeof(char*) + 2) * nArg);
+
+    if( azArg ){
+      char *pSpace = (char*)&azArg[nArg];
+      if( pConfig->t.azArg ){
+        *pzErr = sqlite3_mprintf("multiple tokenize=... directives");
+        rc = SQLITE_ERROR;
+      }else{
+        for(nArg=0; p && *p; nArg++){
+          const char *p2 = fts5ConfigSkipWhitespace(p);
+          if( *p2=='\'' ){
+            p = fts5ConfigSkipLiteral(p2);
+          }else{
+            p = fts5ConfigSkipBareword(p2);
+          }
+          if( p ){
+            memcpy(pSpace, p2, p-p2);
+            azArg[nArg] = pSpace;
+            sqlite3Fts5Dequote(pSpace);
+            pSpace += (p - p2) + 1;
+            p = fts5ConfigSkipWhitespace(p);
+          }
+        }
+        if( p==0 ){
+          *pzErr = sqlite3_mprintf("parse error in tokenize directive");
+          rc = SQLITE_ERROR;
+        }else{
+          pConfig->t.azArg = (const char**)azArg;
+          pConfig->t.nArg = nArg;
+          azArg = 0;
+        }
+      }
+    }
+    sqlite3_free(azArg);
+
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("content", zCmd, nCmd)==0 ){
+    if( pConfig->eContent!=FTS5_CONTENT_NORMAL ){
+      *pzErr = sqlite3_mprintf("multiple content=... directives");
+      rc = SQLITE_ERROR;
+    }else{
+      if( zArg[0] ){
+        pConfig->eContent = FTS5_CONTENT_EXTERNAL;
+        pConfig->zContent = sqlite3Fts5Mprintf(&rc, "%Q.%Q", pConfig->zDb,zArg);
+      }else{
+        pConfig->eContent = FTS5_CONTENT_NONE;
+      }
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("contentless_delete", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed contentless_delete=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bContentlessDelete = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("contentless_unindexed", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed contentless_delete=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bContentlessUnindexed = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("content_rowid", zCmd, nCmd)==0 ){
+    if( pConfig->zContentRowid ){
+      *pzErr = sqlite3_mprintf("multiple content_rowid=... directives");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->zContentRowid = sqlite3Fts5Strndup(&rc, zArg, -1);
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("columnsize", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed columnsize=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bColumnsize = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("locale", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed locale=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bLocale = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("detail", zCmd, nCmd)==0 ){
+    const Fts5Enum aDetail[] = {
+      { "none", FTS5_DETAIL_NONE },
+      { "full", FTS5_DETAIL_FULL },
+      { "columns", FTS5_DETAIL_COLUMNS },
+      { 0, 0 }
+    };
+
+    if( (rc = fts5ConfigSetEnum(aDetail, zArg, &pConfig->eDetail)) ){
+      *pzErr = sqlite3_mprintf("malformed detail=... directive");
+    }
+    return rc;
+  }
+
+  if( sqlite3_strnicmp("tokendata", zCmd, nCmd)==0 ){
+    if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1]!='\0' ){
+      *pzErr = sqlite3_mprintf("malformed tokendata=... directive");
+      rc = SQLITE_ERROR;
+    }else{
+      pConfig->bTokendata = (zArg[0]=='1');
+    }
+    return rc;
+  }
+
+  *pzErr = sqlite3_mprintf("unrecognized option: \"%.*s\"", nCmd, zCmd);
+  return SQLITE_ERROR;
+}
+
+/*
+** Gobble up the first bareword or quoted word from the input buffer zIn.
+** Return a pointer to the character immediately following the last in
+** the gobbled word if successful, or a NULL pointer otherwise (failed
+** to find close-quote character).
+**
+** Before returning, set pzOut to point to a new buffer containing a
+** nul-terminated, dequoted copy of the gobbled word. If the word was
+** quoted, *pbQuoted is also set to 1 before returning.
+**
+** If *pRc is other than SQLITE_OK when this function is called, it is
+** a no-op (NULL is returned). Otherwise, if an OOM occurs within this
+** function, *pRc is set to SQLITE_NOMEM before returning. *pRc is *not*
+** set if a parse error (failed to find close quote) occurs.
+*/
+static const char *fts5ConfigGobbleWord(
+  int *pRc,                       /* IN/OUT: Error code */
+  const char *zIn,                /* Buffer to gobble string/bareword from */
+  char **pzOut,                   /* OUT: malloc'd buffer containing str/bw */
+  int *pbQuoted                   /* OUT: Set to true if dequoting required */
+){
+  const char *zRet = 0;
+
+  sqlite3_int64 nIn = strlen(zIn);
+  char *zOut = sqlite3_malloc64(nIn+1);
+
+  assert( *pRc==SQLITE_OK );
+  *pbQuoted = 0;
+  *pzOut = 0;
+
+  if( zOut==0 ){
+    *pRc = SQLITE_NOMEM;
+  }else{
+    memcpy(zOut, zIn, (size_t)(nIn+1));
+    if( fts5_isopenquote(zOut[0]) ){
+      int ii = fts5Dequote(zOut);
+      zRet = &zIn[ii];
+      *pbQuoted = 1;
+    }else{
+      zRet = fts5ConfigSkipBareword(zIn);
+      if( zRet ){
+        zOut[zRet-zIn] = '\0';
+      }
+    }
+  }
+
+  if( zRet==0 ){
+    sqlite3_free(zOut);
+  }else{
+    *pzOut = zOut;
+  }
+
+  return zRet;
+}
+
+static int fts5ConfigParseColumn(
+  Fts5Config *p,
+  char *zCol,
+  char *zArg,
+  char **pzErr,
+  int *pbUnindexed
+){
+  int rc = SQLITE_OK;
+  if( 0==sqlite3_stricmp(zCol, FTS5_RANK_NAME)
+   || 0==sqlite3_stricmp(zCol, FTS5_ROWID_NAME)
+  ){
+    *pzErr = sqlite3_mprintf("reserved fts5 column name: %s", zCol);
+    rc = SQLITE_ERROR;
+  }else if( zArg ){
+    if( 0==sqlite3_stricmp(zArg, "unindexed") ){
+      p->abUnindexed[p->nCol] = 1;
+      *pbUnindexed = 1;
+    }else{
+      *pzErr = sqlite3_mprintf("unrecognized column option: %s", zArg);
+      rc = SQLITE_ERROR;
+    }
+  }
+
+  p->azCol[p->nCol++] = zCol;
+  return rc;
+}
+
+/*
+** Populate the Fts5Config.zContentExprlist string.
+*/
+static int fts5ConfigMakeExprlist(Fts5Config *p){
+  int i;
+  int rc = SQLITE_OK;
+  Fts5Buffer buf = {0, 0, 0};
+
+  sqlite3Fts5BufferAppendPrintf(&rc, &buf, "T.%Q", p->zContentRowid);
+  if( p->eContent!=FTS5_CONTENT_NONE ){
+    assert( p->eContent==FTS5_CONTENT_EXTERNAL
+         || p->eContent==FTS5_CONTENT_NORMAL
+         || p->eContent==FTS5_CONTENT_UNINDEXED
+    );
+    for(i=0; i<p->nCol; i++){
+      if( p->eContent==FTS5_CONTENT_EXTERNAL ){
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", T.%Q", p->azCol[i]);
+      }else if( p->eContent==FTS5_CONTENT_NORMAL || p->abUnindexed[i] ){
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", T.c%d", i);
+      }else{
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", NULL");
+      }
+    }
+  }
+  if( p->eContent==FTS5_CONTENT_NORMAL && p->bLocale ){
+    for(i=0; i<p->nCol; i++){
+      if( p->abUnindexed[i]==0 ){
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", T.l%d", i);
+      }else{
+        sqlite3Fts5BufferAppendPrintf(&rc, &buf, ", NULL");
+      }
+    }
+  }
+
+  assert( p->zContentExprlist==0 );
+  p->zContentExprlist = (char*)buf.p;
+  return rc;
+}
+
+/*
+** Arguments nArg/azArg contain the string arguments passed to the xCreate
+** or xConnect method of the virtual table. This function attempts to
+** allocate an instance of Fts5Config containing the results of parsing
+** those arguments.
+**
+** If successful, SQLITE_OK is returned and *ppOut is set to point to the
+** new Fts5Config object. If an error occurs, an SQLite error code is
+** returned, *ppOut is set to NULL and an error message may be left in
+** *pzErr. It is the responsibility of the caller to eventually free any
+** such error message using sqlite3_free().
+*/
+static int sqlite3Fts5ConfigParse(
+  Fts5Global *pGlobal,
+  sqlite3 *db,
+  int nArg,                       /* Number of arguments */
+  const char **azArg,             /* Array of nArg CREATE VIRTUAL TABLE args */
+  Fts5Config **ppOut,             /* OUT: Results of parse */
+  char **pzErr                    /* OUT: Error message */
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5Config *pRet;               /* New object to return */
+  int i;
+  sqlite3_int64 nByte;
+  int bUnindexed = 0;             /* True if there are one or more UNINDEXED */
+
+  *ppOut = pRet = (Fts5Config*)sqlite3_malloc(sizeof(Fts5Config));
+  if( pRet==0 ) return SQLITE_NOMEM;
+  memset(pRet, 0, sizeof(Fts5Config));
+  pRet->pGlobal = pGlobal;
+  pRet->db = db;
+  pRet->iCookie = -1;
+
+  nByte = nArg * (sizeof(char*) + sizeof(u8));
+  pRet->azCol = (char**)sqlite3Fts5MallocZero(&rc, nByte);
+  pRet->abUnindexed = pRet->azCol ? (u8*)&pRet->azCol[nArg] : 0;
+  pRet->zDb = sqlite3Fts5Strndup(&rc, azArg[1], -1);
+  pRet->zName = sqlite3Fts5Strndup(&rc, azArg[2], -1);
+  pRet->bColumnsize = 1;
+  pRet->eDetail = FTS5_DETAIL_FULL;
+#ifdef SQLITE_DEBUG
+  pRet->bPrefixIndex = 1;
+#endif
+  if( rc==SQLITE_OK && sqlite3_stricmp(pRet->zName, FTS5_RANK_NAME)==0 ){
+    *pzErr = sqlite3_mprintf("reserved fts5 table name: %s", pRet->zName);
+    rc = SQLITE_ERROR;
+  }
+
+  assert( (pRet->abUnindexed && pRet->azCol) || rc!=SQLITE_OK );
+  for(i=3; rc==SQLITE_OK && i<nArg; i++){
+    const char *zOrig = azArg[i];
+    const char *z;
+    char *zOne = 0;
+    char *zTwo = 0;
+    int bOption = 0;
+    int bMustBeCol = 0;
+
+    z = fts5ConfigGobbleWord(&rc, zOrig, &zOne, &bMustBeCol);
+    z = fts5ConfigSkipWhitespace(z);
+    if( z && *z=='=' ){
+      bOption = 1;
+      assert( zOne!=0 );
+      z++;
+      if( bMustBeCol ) z = 0;
+    }
+    z = fts5ConfigSkipWhitespace(z);
+    if( z && z[0] ){
+      int bDummy;
+      z = fts5ConfigGobbleWord(&rc, z, &zTwo, &bDummy);
+      if( z && z[0] ) z = 0;
+    }
+
+    if( rc==SQLITE_OK ){
+      if( z==0 ){
+        *pzErr = sqlite3_mprintf("parse error in \"%s\"", zOrig);
+        rc = SQLITE_ERROR;
+      }else{
+        if( bOption ){
+          rc = fts5ConfigParseSpecial(pRet,
+            ALWAYS(zOne)?zOne:"",
+            zTwo?zTwo:"",
+            pzErr
+          );
+        }else{
+          rc = fts5ConfigParseColumn(pRet, zOne, zTwo, pzErr, &bUnindexed);
+          zOne = 0;
+        }
+      }
+    }
+
+    sqlite3_free(zOne);
+    sqlite3_free(zTwo);
+  }
+
+  /* We only allow contentless_delete=1 if the table is indeed contentless. */
+  if( rc==SQLITE_OK
+   && pRet->bContentlessDelete
+   && pRet->eContent!=FTS5_CONTENT_NONE
+  ){
+    *pzErr = sqlite3_mprintf(
+        "contentless_delete=1 requires a contentless table"
+    );
+    rc = SQLITE_ERROR;
+  }
+
+  /* We only allow contentless_delete=1 if columnsize=0 is not present.
+  **
+  ** This restriction may be removed at some point.
+  */
+  if( rc==SQLITE_OK && pRet->bContentlessDelete && pRet->bColumnsize==0 ){
+    *pzErr = sqlite3_mprintf(
+        "contentless_delete=1 is incompatible with columnsize=0"
+    );
+    rc = SQLITE_ERROR;
+  }
+
+  /* We only allow contentless_unindexed=1 if the table is actually a
+  ** contentless one.
+  */
+  if( rc==SQLITE_OK
+   && pRet->bContentlessUnindexed
+   && pRet->eContent!=FTS5_CONTENT_NONE
+  ){
+    *pzErr = sqlite3_mprintf(
+        "contentless_unindexed=1 requires a contentless table"
+    );
+    rc = SQLITE_ERROR;
+  }
+
+  /* If no zContent option was specified, fill in the default values. */
+  if( rc==SQLITE_OK && pRet->zContent==0 ){
+    const char *zTail = 0;
+    assert( pRet->eContent==FTS5_CONTENT_NORMAL
+         || pRet->eContent==FTS5_CONTENT_NONE
+    );
+    if( pRet->eContent==FTS5_CONTENT_NORMAL ){
+      zTail = "content";
+    }else if( bUnindexed && pRet->bContentlessUnindexed ){
+      pRet->eContent = FTS5_CONTENT_UNINDEXED;
+      zTail = "content";
+    }else if( pRet->bColumnsize ){
+      zTail = "docsize";
+    }
+
+    if( zTail ){
+      pRet->zContent = sqlite3Fts5Mprintf(
+          &rc, "%Q.'%q_%s'", pRet->zDb, pRet->zName, zTail
+      );
+    }
+  }
+
+  if( rc==SQLITE_OK && pRet->zContentRowid==0 ){
+    pRet->zContentRowid = sqlite3Fts5Strndup(&rc, "rowid", -1);
+  }
+
+  /* Formulate the zContentExprlist text */
+  if( rc==SQLITE_OK ){
+    rc = fts5ConfigMakeExprlist(pRet);
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3Fts5ConfigFree(pRet);
+    *ppOut = 0;
+  }
+  return rc;
+}
+
+/*
+** Free the configuration object passed as the only argument.
+*/
+static void sqlite3Fts5ConfigFree(Fts5Config *pConfig){
+  if( pConfig ){
+    int i;
+    if( pConfig->t.pTok ){
+      if( pConfig->t.pApi1 ){
+        pConfig->t.pApi1->xDelete(pConfig->t.pTok);
+      }else{
+        pConfig->t.pApi2->xDelete(pConfig->t.pTok);
+      }
+    }
+    sqlite3_free((char*)pConfig->t.azArg);
+    sqlite3_free(pConfig->zDb);
+    sqlite3_free(pConfig->zName);
+    for(i=0; i<pConfig->nCol; i++){
+      sqlite3_free(pConfig->azCol[i]);
+    }
+    sqlite3_free(pConfig->azCol);
+    sqlite3_free(pConfig->aPrefix);
+    sqlite3_free(pConfig->zRank);
+    sqlite3_free(pConfig->zRankArgs);
+    sqlite3_free(pConfig->zContent);
+    sqlite3_free(pConfig->zContentRowid);
+    sqlite3_free(pConfig->zContentExprlist);
+    sqlite3_free(pConfig);
+  }
+}
+
+/*
+** Call sqlite3_declare_vtab() based on the contents of the configuration
+** object passed as the only argument. Return SQLITE_OK if successful, or
+** an SQLite error code if an error occurs.
+*/
+static int sqlite3Fts5ConfigDeclareVtab(Fts5Config *pConfig){
+  int i;
+  int rc = SQLITE_OK;
+  char *zSql;
+
+  zSql = sqlite3Fts5Mprintf(&rc, "CREATE TABLE x(");
+  for(i=0; zSql && i<pConfig->nCol; i++){
+    const char *zSep = (i==0?"":", ");
+    zSql = sqlite3Fts5Mprintf(&rc, "%z%s%Q", zSql, zSep, pConfig->azCol[i]);
+  }
+  zSql = sqlite3Fts5Mprintf(&rc, "%z, %Q HIDDEN, %s HIDDEN)",
+      zSql, pConfig->zName, FTS5_RANK_NAME
+  );
+
+  assert( zSql || rc==SQLITE_NOMEM );
+  if( zSql ){
+    rc = sqlite3_declare_vtab(pConfig->db, zSql);
+    sqlite3_free(zSql);
+  }
+
+  return rc;
+}
+
+/*
+** Tokenize the text passed via the second and third arguments.
+**
+** The callback is invoked once for each token in the input text. The
+** arguments passed to it are, in order:
+**
+**     void *pCtx          // Copy of 4th argument to sqlite3Fts5Tokenize()
+**     const char *pToken  // Pointer to buffer containing token
+**     int nToken          // Size of token in bytes
+**     int iStart          // Byte offset of start of token within input text
+**     int iEnd            // Byte offset of end of token within input text
+**     int iPos            // Position of token in input (first token is 0)
+**
+** If the callback returns a non-zero value the tokenization is abandoned
+** and no further callbacks are issued.
+**
+** This function returns SQLITE_OK if successful or an SQLite error code
+** if an error occurs. If the tokenization was abandoned early because
+** the callback returned SQLITE_DONE, this is not an error and this function
+** still returns SQLITE_OK. Or, if the tokenization was abandoned early
+** because the callback returned another non-zero value, it is assumed
+** to be an SQLite error code and returned to the caller.
+*/
+static int sqlite3Fts5Tokenize(
+  Fts5Config *pConfig,            /* FTS5 Configuration object */
+  int flags,                      /* FTS5_TOKENIZE_* flags */
+  const char *pText, int nText,   /* Text to tokenize */
+  void *pCtx,                     /* Context passed to xToken() */
+  int (*xToken)(void*, int, const char*, int, int, int)    /* Callback */
+){
+  int rc = SQLITE_OK;
+  if( pText ){
+    if( pConfig->t.pTok==0 ){
+      rc = sqlite3Fts5LoadTokenizer(pConfig);
+    }
+    if( rc==SQLITE_OK ){
+      if( pConfig->t.pApi1 ){
+        rc = pConfig->t.pApi1->xTokenize(
+            pConfig->t.pTok, pCtx, flags, pText, nText, xToken
+        );
+      }else{
+        rc = pConfig->t.pApi2->xTokenize(pConfig->t.pTok, pCtx, flags,
+            pText, nText, pConfig->t.pLocale, pConfig->t.nLocale, xToken
+        );
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** Argument pIn points to the first character in what is expected to be
+** a comma-separated list of SQL literals followed by a ')' character.
+** If it actually is this, return a pointer to the ')'. Otherwise, return
+** NULL to indicate a parse error.
+*/
+static const char *fts5ConfigSkipArgs(const char *pIn){
+  const char *p = pIn;
+
+  while( 1 ){
+    p = fts5ConfigSkipWhitespace(p);
+    p = fts5ConfigSkipLiteral(p);
+    p = fts5ConfigSkipWhitespace(p);
+    if( p==0 || *p==')' ) break;
+    if( *p!=',' ){
+      p = 0;
+      break;
+    }
+    p++;
+  }
+
+  return p;
+}
+
+/*
+** Parameter zIn contains a rank() function specification. The format of
+** this is:
+**
+**   + Bareword (function name)
+**   + Open parenthesis - "("
+**   + Zero or more SQL literals in a comma separated list
+**   + Close parenthesis - ")"
+*/
+static int sqlite3Fts5ConfigParseRank(
+  const char *zIn,                /* Input string */
+  char **pzRank,                  /* OUT: Rank function name */
+  char **pzRankArgs               /* OUT: Rank function arguments */
+){
+  const char *p = zIn;
+  const char *pRank;
+  char *zRank = 0;
+  char *zRankArgs = 0;
+  int rc = SQLITE_OK;
+
+  *pzRank = 0;
+  *pzRankArgs = 0;
+
+  if( p==0 ){
+    rc = SQLITE_ERROR;
+  }else{
+    p = fts5ConfigSkipWhitespace(p);
+    pRank = p;
+    p = fts5ConfigSkipBareword(p);
+
+    if( p ){
+      zRank = sqlite3Fts5MallocZero(&rc, 1 + p - pRank);
+      if( zRank ) memcpy(zRank, pRank, p-pRank);
+    }else{
+      rc = SQLITE_ERROR;
+    }
+
+    if( rc==SQLITE_OK ){
+      p = fts5ConfigSkipWhitespace(p);
+      if( *p!='(' ) rc = SQLITE_ERROR;
+      p++;
+    }
+    if( rc==SQLITE_OK ){
+      const char *pArgs;
+      p = fts5ConfigSkipWhitespace(p);
+      pArgs = p;
+      if( *p!=')' ){
+        p = fts5ConfigSkipArgs(p);
+        if( p==0 ){
+          rc = SQLITE_ERROR;
+        }else{
+          zRankArgs = sqlite3Fts5MallocZero(&rc, 1 + p - pArgs);
+          if( zRankArgs ) memcpy(zRankArgs, pArgs, p-pArgs);
+        }
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_free(zRank);
+    assert( zRankArgs==0 );
+  }else{
+    *pzRank = zRank;
+    *pzRankArgs = zRankArgs;
+  }
+  return rc;
+}
+
+static int sqlite3Fts5ConfigSetValue(
+  Fts5Config *pConfig,
+  const char *zKey,
+  sqlite3_value *pVal,
+  int *pbBadkey
+){
+  int rc = SQLITE_OK;
+
+  if( 0==sqlite3_stricmp(zKey, "pgsz") ){
+    int pgsz = 0;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      pgsz = sqlite3_value_int(pVal);
+    }
+    if( pgsz<32 || pgsz>FTS5_MAX_PAGE_SIZE ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->pgsz = pgsz;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "hashsize") ){
+    int nHashSize = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nHashSize = sqlite3_value_int(pVal);
+    }
+    if( nHashSize<=0 ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->nHashSize = nHashSize;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "automerge") ){
+    int nAutomerge = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nAutomerge = sqlite3_value_int(pVal);
+    }
+    if( nAutomerge<0 || nAutomerge>64 ){
+      *pbBadkey = 1;
+    }else{
+      if( nAutomerge==1 ) nAutomerge = FTS5_DEFAULT_AUTOMERGE;
+      pConfig->nAutomerge = nAutomerge;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "usermerge") ){
+    int nUsermerge = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nUsermerge = sqlite3_value_int(pVal);
+    }
+    if( nUsermerge<2 || nUsermerge>16 ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->nUsermerge = nUsermerge;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "crisismerge") ){
+    int nCrisisMerge = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nCrisisMerge = sqlite3_value_int(pVal);
+    }
+    if( nCrisisMerge<0 ){
+      *pbBadkey = 1;
+    }else{
+      if( nCrisisMerge<=1 ) nCrisisMerge = FTS5_DEFAULT_CRISISMERGE;
+      if( nCrisisMerge>=FTS5_MAX_SEGMENT ) nCrisisMerge = FTS5_MAX_SEGMENT-1;
+      pConfig->nCrisisMerge = nCrisisMerge;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "deletemerge") ){
+    int nVal = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      nVal = sqlite3_value_int(pVal);
+    }else{
+      *pbBadkey = 1;
+    }
+    if( nVal<0 ) nVal = FTS5_DEFAULT_DELETE_AUTOMERGE;
+    if( nVal>100 ) nVal = 0;
+    pConfig->nDeleteMerge = nVal;
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "rank") ){
+    const char *zIn = (const char*)sqlite3_value_text(pVal);
+    char *zRank;
+    char *zRankArgs;
+    rc = sqlite3Fts5ConfigParseRank(zIn, &zRank, &zRankArgs);
+    if( rc==SQLITE_OK ){
+      sqlite3_free(pConfig->zRank);
+      sqlite3_free(pConfig->zRankArgs);
+      pConfig->zRank = zRank;
+      pConfig->zRankArgs = zRankArgs;
+    }else if( rc==SQLITE_ERROR ){
+      rc = SQLITE_OK;
+      *pbBadkey = 1;
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "secure-delete") ){
+    int bVal = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      bVal = sqlite3_value_int(pVal);
+    }
+    if( bVal<0 ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->bSecureDelete = (bVal ? 1 : 0);
+    }
+  }
+
+  else if( 0==sqlite3_stricmp(zKey, "insttoken") ){
+    int bVal = -1;
+    if( SQLITE_INTEGER==sqlite3_value_numeric_type(pVal) ){
+      bVal = sqlite3_value_int(pVal);
+    }
+    if( bVal<0 ){
+      *pbBadkey = 1;
+    }else{
+      pConfig->bPrefixInsttoken = (bVal ? 1 : 0);
+    }
+
+  }else{
+    *pbBadkey = 1;
+  }
+  return rc;
+}
+
+/*
+** Load the contents of the %_config table into memory.
+*/
+static int sqlite3Fts5ConfigLoad(Fts5Config *pConfig, int iCookie){
+  const char *zSelect = "SELECT k, v FROM %Q.'%q_config'";
+  char *zSql;
+  sqlite3_stmt *p = 0;
+  int rc = SQLITE_OK;
+  int iVersion = 0;
+
+  /* Set default values */
+  pConfig->pgsz = FTS5_DEFAULT_PAGE_SIZE;
+  pConfig->nAutomerge = FTS5_DEFAULT_AUTOMERGE;
+  pConfig->nUsermerge = FTS5_DEFAULT_USERMERGE;
+  pConfig->nCrisisMerge = FTS5_DEFAULT_CRISISMERGE;
+  pConfig->nHashSize = FTS5_DEFAULT_HASHSIZE;
+  pConfig->nDeleteMerge = FTS5_DEFAULT_DELETE_AUTOMERGE;
+
+  zSql = sqlite3Fts5Mprintf(&rc, zSelect, pConfig->zDb, pConfig->zName);
+  if( zSql ){
+    rc = sqlite3_prepare_v2(pConfig->db, zSql, -1, &p, 0);
+    sqlite3_free(zSql);
+  }
+
+  assert( rc==SQLITE_OK || p==0 );
+  if( rc==SQLITE_OK ){
+    while( SQLITE_ROW==sqlite3_step(p) ){
+      const char *zK = (const char*)sqlite3_column_text(p, 0);
+      sqlite3_value *pVal = sqlite3_column_value(p, 1);
+      if( 0==sqlite3_stricmp(zK, "version") ){
+        iVersion = sqlite3_value_int(pVal);
+      }else{
+        int bDummy = 0;
+        sqlite3Fts5ConfigSetValue(pConfig, zK, pVal, &bDummy);
+      }
+    }
+    rc = sqlite3_finalize(p);
+  }
+
+  if( rc==SQLITE_OK
+   && iVersion!=FTS5_CURRENT_VERSION
+   && iVersion!=FTS5_CURRENT_VERSION_SECUREDELETE
+  ){
+    rc = SQLITE_ERROR;
+    sqlite3Fts5ConfigErrmsg(pConfig, "invalid fts5 file format "
+        "(found %d, expected %d or %d) - run 'rebuild'",
+        iVersion, FTS5_CURRENT_VERSION, FTS5_CURRENT_VERSION_SECUREDELETE
+    );
+  }else{
+    pConfig->iVersion = iVersion;
+  }
+
+  if( rc==SQLITE_OK ){
+    pConfig->iCookie = iCookie;
+  }
+  return rc;
+}
+
+/*
+** Set (*pConfig->pzErrmsg) to point to an sqlite3_malloc()ed buffer
+** containing the error message created using printf() style formatting
+** string zFmt and its trailing arguments.
+*/
+static void sqlite3Fts5ConfigErrmsg(Fts5Config *pConfig, const char *zFmt, ...){
+  va_list ap;                     /* ... printf arguments */
+  char *zMsg = 0;
+
+  va_start(ap, zFmt);
+  zMsg = sqlite3_vmprintf(zFmt, ap);
+  if( pConfig->pzErrmsg ){
+    assert( *pConfig->pzErrmsg==0 );
+    *pConfig->pzErrmsg = zMsg;
+  }else{
+    sqlite3_free(zMsg);
+  }
+
+  va_end(ap);
+}
+
+
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+
+
+
+/* #include "fts5Int.h" */
+/* #include "fts5parse.h" */
+
+#ifndef SQLITE_FTS5_MAX_EXPR_DEPTH
+# define SQLITE_FTS5_MAX_EXPR_DEPTH 256
+#endif
+
+/*
+** All token types in the generated fts5parse.h file are greater than 0.
+*/
+#define FTS5_EOF 0
+
+#define FTS5_LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
+
+typedef struct Fts5ExprTerm Fts5ExprTerm;
+
+/*
+** Functions generated by lemon from fts5parse.y.
+*/
+static void *sqlite3Fts5ParserAlloc(void *(*mallocProc)(u64));
+static void sqlite3Fts5ParserFree(void*, void (*freeProc)(void*));
+static void sqlite3Fts5Parser(void*, int, Fts5Token, Fts5Parse*);
+#ifndef NDEBUG
+/* #include <stdio.h> */
+static void sqlite3Fts5ParserTrace(FILE*, char*);
+#endif
+static int sqlite3Fts5ParserFallback(int);
+
+
+struct Fts5Expr {
+  Fts5Index *pIndex;
+  Fts5Config *pConfig;
+  Fts5ExprNode *pRoot;
+  int bDesc;                      /* Iterate in descending rowid order */
+  int nPhrase;                    /* Number of phrases in expression */
+  Fts5ExprPhrase **apExprPhrase;  /* Pointers to phrase objects */
+};
+
+/*
+** eType:
+**   Expression node type. Usually one of:
+**
+**       FTS5_AND                 (nChild, apChild valid)
+**       FTS5_OR                  (nChild, apChild valid)
+**       FTS5_NOT                 (nChild, apChild valid)
+**       FTS5_STRING              (pNear valid)
+**       FTS5_TERM                (pNear valid)
+**
+**   An expression node with eType==0 may also exist. It always matches zero
+**   rows. This is created when a phrase containing no tokens is parsed.
+**   e.g. "".
+**
+** iHeight:
+**   Distance from this node to furthest leaf. This is always 0 for nodes
+**   of type FTS5_STRING and FTS5_TERM. For all other nodes it is one
+**   greater than the largest child value.
+*/
+struct Fts5ExprNode {
+  int eType;                      /* Node type */
+  int bEof;                       /* True at EOF */
+  int bNomatch;                   /* True if entry is not a match */
+  int iHeight;                    /* Distance to tree leaf nodes */
+
+  /* Next method for this node. */
+  int (*xNext)(Fts5Expr*, Fts5ExprNode*, int, i64);
+
+  i64 iRowid;                     /* Current rowid */
+  Fts5ExprNearset *pNear;         /* For FTS5_STRING - cluster of phrases */
+
+  /* Child nodes. For a NOT node, this array always contains 2 entries. For
+  ** AND or OR nodes, it contains 2 or more entries.  */
+  int nChild;                     /* Number of child nodes */
+  Fts5ExprNode *apChild[1];       /* Array of child nodes */
+};
+
+#define Fts5NodeIsString(p) ((p)->eType==FTS5_TERM || (p)->eType==FTS5_STRING)
+
+/*
+** Invoke the xNext method of an Fts5ExprNode object. This macro should be
+** used as if it has the same signature as the xNext() methods themselves.
+*/
+#define fts5ExprNodeNext(a,b,c,d) (b)->xNext((a), (b), (c), (d))
+
+/*
+** An instance of the following structure represents a single search term
+** or term prefix.
+*/
+struct Fts5ExprTerm {
+  u8 bPrefix;                     /* True for a prefix term */
+  u8 bFirst;                      /* True if token must be first in column */
+  char *pTerm;                    /* Term data */
+  int nQueryTerm;                 /* Effective size of term in bytes */
+  int nFullTerm;                  /* Size of term in bytes incl. tokendata */
+  Fts5IndexIter *pIter;           /* Iterator for this term */
+  Fts5ExprTerm *pSynonym;         /* Pointer to first in list of synonyms */
+};
+
+/*
+** A phrase. One or more terms that must appear in a contiguous sequence
+** within a document for it to match.
+*/
+struct Fts5ExprPhrase {
+  Fts5ExprNode *pNode;            /* FTS5_STRING node this phrase is part of */
+  Fts5Buffer poslist;             /* Current position list */
+  int nTerm;                      /* Number of entries in aTerm[] */
+  Fts5ExprTerm aTerm[1];          /* Terms that make up this phrase */
+};
+
+/*
+** One or more phrases that must appear within a certain token distance of
+** each other within each matching document.
+*/
+struct Fts5ExprNearset {
+  int nNear;                      /* NEAR parameter */
+  Fts5Colset *pColset;            /* Columns to search (NULL -> all columns) */
+  int nPhrase;                    /* Number of entries in aPhrase[] array */
+  Fts5ExprPhrase *apPhrase[1];    /* Array of phrase pointers */
+};
+
+
+/*
+** Parse context.
+*/
+struct Fts5Parse {
+  Fts5Config *pConfig;
+  char *zErr;
+  int rc;
+  int nPhrase;                    /* Size of apPhrase array */
+  Fts5ExprPhrase **apPhrase;      /* Array of all phrases */
+  Fts5ExprNode *pExpr;            /* Result of a successful parse */
+  int bPhraseToAnd;               /* Convert "a+b" to "a AND b" */
+};
+
+/*
+** Check that the Fts5ExprNode.iHeight variables are set correctly in
+** the expression tree passed as the only argument.
+*/
+#ifndef NDEBUG
+static void assert_expr_depth_ok(int rc, Fts5ExprNode *p){
+  if( rc==SQLITE_OK ){
+    if( p->eType==FTS5_TERM || p->eType==FTS5_STRING || p->eType==0 ){
+      assert( p->iHeight==0 );
+    }else{
+      int ii;
+      int iMaxChild = 0;
+      for(ii=0; ii<p->nChild; ii++){
+        Fts5ExprNode *pChild = p->apChild[ii];
+        iMaxChild = MAX(iMaxChild, pChild->iHeight);
+        assert_expr_depth_ok(SQLITE_OK, pChild);
+      }
+      assert( p->iHeight==iMaxChild+1 );
+    }
+  }
+}
+#else
+# define assert_expr_depth_ok(rc, p)
+#endif
+
+static void sqlite3Fts5ParseError(Fts5Parse *pParse, const char *zFmt, ...){
+  va_list ap;
+  va_start(ap, zFmt);
+  if( pParse->rc==SQLITE_OK ){
+    assert( pParse->zErr==0 );
+    pParse->zErr = sqlite3_vmprintf(zFmt, ap);
+    pParse->rc = SQLITE_ERROR;
+  }
+  va_end(ap);
+}
+
+static int fts5ExprIsspace(char t){
+  return t==' ' || t=='\t' || t=='\n' || t=='\r';
+}
+
+/*
+** Read the first token from the nul-terminated string at *pz.
+*/
+static int fts5ExprGetToken(
+  Fts5Parse *pParse,
+  const char **pz,                /* IN/OUT: Pointer into buffer */
+  Fts5Token *pToken
+){
+  const char *z = *pz;
+  int tok;
+
+  /* Skip past any whitespace */
+  while( fts5ExprIsspace(*z) ) z++;
+
+  pToken->p = z;
+  pToken->n = 1;
+  switch( *z ){
+    case '(':  tok = FTS5_LP;    break;
+    case ')':  tok = FTS5_RP;    break;
+    case '{':  tok = FTS5_LCP;   break;
+    case '}':  tok = FTS5_RCP;   break;
+    case ':':  tok = FTS5_COLON; break;
+    case ',':  tok = FTS5_COMMA; break;
+    case '+':  tok = FTS5_PLUS;  break;
+    case '*':  tok = FTS5_STAR;  break;
+    case '-':  tok = FTS5_MINUS; break;
+    case '^':  tok = FTS5_CARET; break;
+    case '\0': tok = FTS5_EOF;   break;
+
+    case '"': {
+      const char *z2;
+      tok = FTS5_STRING;
+
+      for(z2=&z[1]; 1; z2++){
+        if( z2[0]=='"' ){
+          z2++;
+          if( z2[0]!='"' ) break;
+        }
+        if( z2[0]=='\0' ){
+          sqlite3Fts5ParseError(pParse, "unterminated string");
+          return FTS5_EOF;
+        }
+      }
+      pToken->n = (z2 - z);
+      break;
+    }
+
+    default: {
+      const char *z2;
+      if( sqlite3Fts5IsBareword(z[0])==0 ){
+        sqlite3Fts5ParseError(pParse, "fts5: syntax error near \"%.1s\"", z);
+        return FTS5_EOF;
+      }
+      tok = FTS5_STRING;
+      for(z2=&z[1]; sqlite3Fts5IsBareword(*z2); z2++);
+      pToken->n = (z2 - z);
+      if( pToken->n==2 && memcmp(pToken->p, "OR", 2)==0 )  tok = FTS5_OR;
+      if( pToken->n==3 && memcmp(pToken->p, "NOT", 3)==0 ) tok = FTS5_NOT;
+      if( pToken->n==3 && memcmp(pToken->p, "AND", 3)==0 ) tok = FTS5_AND;
+      break;
+    }
+  }
+
+  *pz = &pToken->p[pToken->n];
+  return tok;
+}
+
+static void *fts5ParseAlloc(u64 t){ return sqlite3_malloc64((sqlite3_int64)t);}
+static void fts5ParseFree(void *p){ sqlite3_free(p); }
+
+static int sqlite3Fts5ExprNew(
+  Fts5Config *pConfig,            /* FTS5 Configuration */
+  int bPhraseToAnd,
+  int iCol,
+  const char *zExpr,              /* Expression text */
+  Fts5Expr **ppNew,
+  char **pzErr
+){
+  Fts5Parse sParse;
+  Fts5Token token;
+  const char *z = zExpr;
+  int t;                          /* Next token type */
+  void *pEngine;
+  Fts5Expr *pNew;
+
+  *ppNew = 0;
+  *pzErr = 0;
+  memset(&sParse, 0, sizeof(sParse));
+  sParse.bPhraseToAnd = bPhraseToAnd;
+  pEngine = sqlite3Fts5ParserAlloc(fts5ParseAlloc);
+  if( pEngine==0 ){ return SQLITE_NOMEM; }
+  sParse.pConfig = pConfig;
+
+  do {
+    t = fts5ExprGetToken(&sParse, &z, &token);
+    sqlite3Fts5Parser(pEngine, t, token, &sParse);
+  }while( sParse.rc==SQLITE_OK && t!=FTS5_EOF );
+  sqlite3Fts5ParserFree(pEngine, fts5ParseFree);
+
+  assert( sParse.pExpr || sParse.rc!=SQLITE_OK );
+  assert_expr_depth_ok(sParse.rc, sParse.pExpr);
+
+  /* If the LHS of the MATCH expression was a user column, apply the
+  ** implicit column-filter.  */
+  if( sParse.rc==SQLITE_OK && iCol<pConfig->nCol ){
+    int n = sizeof(Fts5Colset);
+    Fts5Colset *pColset = (Fts5Colset*)sqlite3Fts5MallocZero(&sParse.rc, n);
+    if( pColset ){
+      pColset->nCol = 1;
+      pColset->aiCol[0] = iCol;
+      sqlite3Fts5ParseSetColset(&sParse, sParse.pExpr, pColset);
+    }
+  }
+
+  assert( sParse.rc!=SQLITE_OK || sParse.zErr==0 );
+  if( sParse.rc==SQLITE_OK ){
+    *ppNew = pNew = sqlite3_malloc(sizeof(Fts5Expr));
+    if( pNew==0 ){
+      sParse.rc = SQLITE_NOMEM;
+      sqlite3Fts5ParseNodeFree(sParse.pExpr);
+    }else{
+      pNew->pRoot = sParse.pExpr;
+      pNew->pIndex = 0;
+      pNew->pConfig = pConfig;
+      pNew->apExprPhrase = sParse.apPhrase;
+      pNew->nPhrase = sParse.nPhrase;
+      pNew->bDesc = 0;
+      sParse.apPhrase = 0;
+    }
+  }else{
+    sqlite3Fts5ParseNodeFree(sParse.pExpr);
+  }
+
+  sqlite3_free(sParse.apPhrase);
+  if( 0==*pzErr ){
+    *pzErr = sParse.zErr;
+  }else{
+    sqlite3_free(sParse.zErr);
+  }
+  return sParse.rc;
+}
+
+/*
+** Assuming that buffer z is at least nByte bytes in size and contains a
+** valid utf-8 string, return the number of characters in the string.
+*/
+static int fts5ExprCountChar(const char *z, int nByte){
+  int nRet = 0;
+  int ii;
+  for(ii=0; ii<nByte; ii++){
+    if( (z[ii] & 0xC0)!=0x80 ) nRet++;
+  }
+  return nRet;
+}
+
+/*
+** This function is only called when using the special 'trigram' tokenizer.
+** Argument zText contains the text of a LIKE or GLOB pattern matched
+** against column iCol. This function creates and compiles an FTS5 MATCH
+** expression that will match a superset of the rows matched by the LIKE or
+** GLOB. If successful, SQLITE_OK is returned. Otherwise, an SQLite error
+** code.
+*/
+static int sqlite3Fts5ExprPattern(
+  Fts5Config *pConfig, int bGlob, int iCol, const char *zText, Fts5Expr **pp
+){
+  i64 nText = strlen(zText);
+  char *zExpr = (char*)sqlite3_malloc64(nText*4 + 1);
+  int rc = SQLITE_OK;
+
+  if( zExpr==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    char aSpec[3];
+    int iOut = 0;
+    int i = 0;
+    int iFirst = 0;
+
+    if( bGlob==0 ){
+      aSpec[0] = '_';
+      aSpec[1] = '%';
+      aSpec[2] = 0;
+    }else{
+      aSpec[0] = '*';
+      aSpec[1] = '?';
+      aSpec[2] = '[';
+    }
+
+    while( i<=nText ){
+      if( i==nText
+       || zText[i]==aSpec[0] || zText[i]==aSpec[1] || zText[i]==aSpec[2]
+      ){
+
+        if( fts5ExprCountChar(&zText[iFirst], i-iFirst)>=3 ){
+          int jj;
+          zExpr[iOut++] = '"';
+          for(jj=iFirst; jj<i; jj++){
+            zExpr[iOut++] = zText[jj];
+            if( zText[jj]=='"' ) zExpr[iOut++] = '"';
+          }
+          zExpr[iOut++] = '"';
+          zExpr[iOut++] = ' ';
+        }
+        if( zText[i]==aSpec[2] ){
+          i += 2;
+          if( zText[i-1]=='^' ) i++;
+          while( i<nText && zText[i]!=']' ) i++;
+        }
+        iFirst = i+1;
+      }
+      i++;
+    }
+    if( iOut>0 ){
+      int bAnd = 0;
+      if( pConfig->eDetail!=FTS5_DETAIL_FULL ){
+        bAnd = 1;
+        if( pConfig->eDetail==FTS5_DETAIL_NONE ){
+          iCol = pConfig->nCol;
+        }
+      }
+      zExpr[iOut] = '\0';
+      rc = sqlite3Fts5ExprNew(pConfig, bAnd, iCol, zExpr, pp,pConfig->pzErrmsg);
+    }else{
+      *pp = 0;
+    }
+    sqlite3_free(zExpr);
+  }
+
+  return rc;
+}
+
+/*
+** Free the expression node object passed as the only argument.
+*/
+static void sqlite3Fts5ParseNodeFree(Fts5ExprNode *p){
+  if( p ){
+    int i;
+    for(i=0; i<p->nChild; i++){
+      sqlite3Fts5ParseNodeFree(p->apChild[i]);
+    }
+    sqlite3Fts5ParseNearsetFree(p->pNear);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Free the expression object passed as the only argument.
+*/
+static void sqlite3Fts5ExprFree(Fts5Expr *p){
+  if( p ){
+    sqlite3Fts5ParseNodeFree(p->pRoot);
+    sqlite3_free(p->apExprPhrase);
+    sqlite3_free(p);
+  }
+}
+
+static int sqlite3Fts5ExprAnd(Fts5Expr **pp1, Fts5Expr *p2){
+  Fts5Parse sParse;
+  memset(&sParse, 0, sizeof(sParse));
+
+  if( *pp1 && p2 ){
+    Fts5Expr *p1 = *pp1;
+    int nPhrase = p1->nPhrase + p2->nPhrase;
+
+    p1->pRoot = sqlite3Fts5ParseNode(&sParse, FTS5_AND, p1->pRoot, p2->pRoot,0);
+    p2->pRoot = 0;
+
+    if( sParse.rc==SQLITE_OK ){
+      Fts5ExprPhrase **ap = (Fts5ExprPhrase**)sqlite3_realloc(
+          p1->apExprPhrase, nPhrase * sizeof(Fts5ExprPhrase*)
+      );
+      if( ap==0 ){
+        sParse.rc = SQLITE_NOMEM;
+      }else{
+        int i;
+        memmove(&ap[p2->nPhrase], ap, p1->nPhrase*sizeof(Fts5ExprPhrase*));
+        for(i=0; i<p2->nPhrase; i++){
+          ap[i] = p2->apExprPhrase[i];
+        }
+        p1->nPhrase = nPhrase;
+        p1->apExprPhrase = ap;
+      }
+    }
+    sqlite3_free(p2->apExprPhrase);
+    sqlite3_free(p2);
+  }else if( p2 ){
+    *pp1 = p2;
+  }
+
+  return sParse.rc;
+}
+
+/*
+** Argument pTerm must be a synonym iterator. Return the current rowid
+** that it points to.
+*/
+static i64 fts5ExprSynonymRowid(Fts5ExprTerm *pTerm, int bDesc, int *pbEof){
+  i64 iRet = 0;
+  int bRetValid = 0;
+  Fts5ExprTerm *p;
+
+  assert( pTerm );
+  assert( pTerm->pSynonym );
+  assert( bDesc==0 || bDesc==1 );
+  for(p=pTerm; p; p=p->pSynonym){
+    if( 0==sqlite3Fts5IterEof(p->pIter) ){
+      i64 iRowid = p->pIter->iRowid;
+      if( bRetValid==0 || (bDesc!=(iRowid<iRet)) ){
+        iRet = iRowid;
+        bRetValid = 1;
+      }
+    }
+  }
+
+  if( pbEof && bRetValid==0 ) *pbEof = 1;
+  return iRet;
+}
+
+/*
+** Argument pTerm must be a synonym iterator.
+*/
+static int fts5ExprSynonymList(
+  Fts5ExprTerm *pTerm,
+  i64 iRowid,
+  Fts5Buffer *pBuf,               /* Use this buffer for space if required */
+  u8 **pa, int *pn
+){
+  Fts5PoslistReader aStatic[4];
+  Fts5PoslistReader *aIter = aStatic;
+  int nIter = 0;
+  int nAlloc = 4;
+  int rc = SQLITE_OK;
+  Fts5ExprTerm *p;
+
+  assert( pTerm->pSynonym );
+  for(p=pTerm; p; p=p->pSynonym){
+    Fts5IndexIter *pIter = p->pIter;
+    if( sqlite3Fts5IterEof(pIter)==0 && pIter->iRowid==iRowid ){
+      if( pIter->nData==0 ) continue;
+      if( nIter==nAlloc ){
+        sqlite3_int64 nByte = sizeof(Fts5PoslistReader) * nAlloc * 2;
+        Fts5PoslistReader *aNew = (Fts5PoslistReader*)sqlite3_malloc64(nByte);
+        if( aNew==0 ){
+          rc = SQLITE_NOMEM;
+          goto synonym_poslist_out;
+        }
+        memcpy(aNew, aIter, sizeof(Fts5PoslistReader) * nIter);
+        nAlloc = nAlloc*2;
+        if( aIter!=aStatic ) sqlite3_free(aIter);
+        aIter = aNew;
+      }
+      sqlite3Fts5PoslistReaderInit(pIter->pData, pIter->nData, &aIter[nIter]);
+      assert( aIter[nIter].bEof==0 );
+      nIter++;
+    }
+  }
+
+  if( nIter==1 ){
+    *pa = (u8*)aIter[0].a;
+    *pn = aIter[0].n;
+  }else{
+    Fts5PoslistWriter writer = {0};
+    i64 iPrev = -1;
+    fts5BufferZero(pBuf);
+    while( 1 ){
+      int i;
+      i64 iMin = FTS5_LARGEST_INT64;
+      for(i=0; i<nIter; i++){
+        if( aIter[i].bEof==0 ){
+          if( aIter[i].iPos==iPrev ){
+            if( sqlite3Fts5PoslistReaderNext(&aIter[i]) ) continue;
+          }
+          if( aIter[i].iPos<iMin ){
+            iMin = aIter[i].iPos;
+          }
+        }
+      }
+      if( iMin==FTS5_LARGEST_INT64 || rc!=SQLITE_OK ) break;
+      rc = sqlite3Fts5PoslistWriterAppend(pBuf, &writer, iMin);
+      iPrev = iMin;
+    }
+    if( rc==SQLITE_OK ){
+      *pa = pBuf->p;
+      *pn = pBuf->n;
+    }
+  }
+
+ synonym_poslist_out:
+  if( aIter!=aStatic ) sqlite3_free(aIter);
+  return rc;
+}
+
+
+/*
+** All individual term iterators in pPhrase are guaranteed to be valid and
+** pointing to the same rowid when this function is called. This function
+** checks if the current rowid really is a match, and if so populates
+** the pPhrase->poslist buffer accordingly. Output parameter *pbMatch
+** is set to true if this is really a match, or false otherwise.
+**
+** SQLITE_OK is returned if an error occurs, or an SQLite error code
+** otherwise. It is not considered an error code if the current rowid is
+** not a match.
+*/
+static int fts5ExprPhraseIsMatch(
+  Fts5ExprNode *pNode,            /* Node pPhrase belongs to */
+  Fts5ExprPhrase *pPhrase,        /* Phrase object to initialize */
+  int *pbMatch                    /* OUT: Set to true if really a match */
+){
+  Fts5PoslistWriter writer = {0};
+  Fts5PoslistReader aStatic[4];
+  Fts5PoslistReader *aIter = aStatic;
+  int i;
+  int rc = SQLITE_OK;
+  int bFirst = pPhrase->aTerm[0].bFirst;
+
+  fts5BufferZero(&pPhrase->poslist);
+
+  /* If the aStatic[] array is not large enough, allocate a large array
+  ** using sqlite3_malloc(). This approach could be improved upon. */
+  if( pPhrase->nTerm>ArraySize(aStatic) ){
+    sqlite3_int64 nByte = sizeof(Fts5PoslistReader) * pPhrase->nTerm;
+    aIter = (Fts5PoslistReader*)sqlite3_malloc64(nByte);
+    if( !aIter ) return SQLITE_NOMEM;
+  }
+  memset(aIter, 0, sizeof(Fts5PoslistReader) * pPhrase->nTerm);
+
+  /* Initialize a term iterator for each term in the phrase */
+  for(i=0; i<pPhrase->nTerm; i++){
+    Fts5ExprTerm *pTerm = &pPhrase->aTerm[i];
+    int n = 0;
+    int bFlag = 0;
+    u8 *a = 0;
+    if( pTerm->pSynonym ){
+      Fts5Buffer buf = {0, 0, 0};
+      rc = fts5ExprSynonymList(pTerm, pNode->iRowid, &buf, &a, &n);
+      if( rc ){
+        sqlite3_free(a);
+        goto ismatch_out;
+      }
+      if( a==buf.p ) bFlag = 1;
+    }else{
+      a = (u8*)pTerm->pIter->pData;
+      n = pTerm->pIter->nData;
+    }
+    sqlite3Fts5PoslistReaderInit(a, n, &aIter[i]);
+    aIter[i].bFlag = (u8)bFlag;
+    if( aIter[i].bEof ) goto ismatch_out;
+  }
+
+  while( 1 ){
+    int bMatch;
+    i64 iPos = aIter[0].iPos;
+    do {
+      bMatch = 1;
+      for(i=0; i<pPhrase->nTerm; i++){
+        Fts5PoslistReader *pPos = &aIter[i];
+        i64 iAdj = iPos + i;
+        if( pPos->iPos!=iAdj ){
+          bMatch = 0;
+          while( pPos->iPos<iAdj ){
+            if( sqlite3Fts5PoslistReaderNext(pPos) ) goto ismatch_out;
+          }
+          if( pPos->iPos>iAdj ) iPos = pPos->iPos-i;
+        }
+      }
+    }while( bMatch==0 );
+
+    /* Append position iPos to the output */
+    if( bFirst==0 || FTS5_POS2OFFSET(iPos)==0 ){
+      rc = sqlite3Fts5PoslistWriterAppend(&pPhrase->poslist, &writer, iPos);
+      if( rc!=SQLITE_OK ) goto ismatch_out;
+    }
+
+    for(i=0; i<pPhrase->nTerm; i++){
+      if( sqlite3Fts5PoslistReaderNext(&aIter[i]) ) goto ismatch_out;
+    }
+  }
+
+ ismatch_out:
+  *pbMatch = (pPhrase->poslist.n>0);
+  for(i=0; i<pPhrase->nTerm; i++){
+    if( aIter[i].bFlag ) sqlite3_free((u8*)aIter[i].a);
+  }
+  if( aIter!=aStatic ) sqlite3_free(aIter);
+  return rc;
+}
+
+typedef struct Fts5LookaheadReader Fts5LookaheadReader;
+struct Fts5LookaheadReader {
+  const u8 *a;                    /* Buffer containing position list */
+  int n;                          /* Size of buffer a[] in bytes */
+  int i;                          /* Current offset in position list */
+  i64 iPos;                       /* Current position */
+  i64 iLookahead;                 /* Next position */
+};
+
+#define FTS5_LOOKAHEAD_EOF (((i64)1) << 62)
+
+static int fts5LookaheadReaderNext(Fts5LookaheadReader *p){
+  p->iPos = p->iLookahead;
+  if( sqlite3Fts5PoslistNext64(p->a, p->n, &p->i, &p->iLookahead) ){
+    p->iLookahead = FTS5_LOOKAHEAD_EOF;
+  }
+  return (p->iPos==FTS5_LOOKAHEAD_EOF);
+}
+
+static int fts5LookaheadReaderInit(
+  const u8 *a, int n,             /* Buffer to read position list from */
+  Fts5LookaheadReader *p          /* Iterator object to initialize */
+){
+  memset(p, 0, sizeof(Fts5LookaheadReader));
+  p->a = a;
+  p->n = n;
+  fts5LookaheadReaderNext(p);
+  return fts5LookaheadReaderNext(p);
+}
+
+typedef struct Fts5NearTrimmer Fts5NearTrimmer;
+struct Fts5NearTrimmer {
+  Fts5LookaheadReader reader;     /* Input iterator */
+  Fts5PoslistWriter writer;       /* Writer context */
+  Fts5Buffer *pOut;               /* Output poslist */
+};
+
+/*
+** The near-set object passed as the first argument contains more than
+** one phrase. All phrases currently point to the same row. The
+** Fts5ExprPhrase.poslist buffers are populated accordingly. This function
+** tests if the current row contains instances of each phrase sufficiently
+** close together to meet the NEAR constraint. Non-zero is returned if it
+** does, or zero otherwise.
+**
+** If in/out parameter (*pRc) is set to other than SQLITE_OK when this
+** function is called, it is a no-op. Or, if an error (e.g. SQLITE_NOMEM)
+** occurs within this function (*pRc) is set accordingly before returning.
+** The return value is undefined in both these cases.
+**
+** If no error occurs and non-zero (a match) is returned, the position-list
+** of each phrase object is edited to contain only those entries that
+** meet the constraint before returning.
+*/
+static int fts5ExprNearIsMatch(int *pRc, Fts5ExprNearset *pNear){
+  Fts5NearTrimmer aStatic[4];
+  Fts5NearTrimmer *a = aStatic;
+  Fts5ExprPhrase **apPhrase = pNear->apPhrase;
+
+  int i;
+  int rc = *pRc;
+  int bMatch;
+
+  assert( pNear->nPhrase>1 );
+
+  /* If the aStatic[] array is not large enough, allocate a large array
+  ** using sqlite3_malloc(). This approach could be improved upon. */
+  if( pNear->nPhrase>ArraySize(aStatic) ){
+    sqlite3_int64 nByte = sizeof(Fts5NearTrimmer) * pNear->nPhrase;
+    a = (Fts5NearTrimmer*)sqlite3Fts5MallocZero(&rc, nByte);
+  }else{
+    memset(aStatic, 0, sizeof(aStatic));
+  }
+  if( rc!=SQLITE_OK ){
+    *pRc = rc;
+    return 0;
+  }
+
+  /* Initialize a lookahead iterator for each phrase. After passing the
+  ** buffer and buffer size to the lookaside-reader init function, zero
+  ** the phrase poslist buffer. The new poslist for the phrase (containing
+  ** the same entries as the original with some entries removed on account
+  ** of the NEAR constraint) is written over the original even as it is
+  ** being read. This is safe as the entries for the new poslist are a
+  ** subset of the old, so it is not possible for data yet to be read to
+  ** be overwritten.  */
+  for(i=0; i<pNear->nPhrase; i++){
+    Fts5Buffer *pPoslist = &apPhrase[i]->poslist;
+    fts5LookaheadReaderInit(pPoslist->p, pPoslist->n, &a[i].reader);
+    pPoslist->n = 0;
+    a[i].pOut = pPoslist;
+  }
+
+  while( 1 ){
+    int iAdv;
+    i64 iMin;
+    i64 iMax;
+
+    /* This block advances the phrase iterators until they point to a set of
+    ** entries that together comprise a match.  */
+    iMax = a[0].reader.iPos;
+    do {
+      bMatch = 1;
+      for(i=0; i<pNear->nPhrase; i++){
+        Fts5LookaheadReader *pPos = &a[i].reader;
+        iMin = iMax - pNear->apPhrase[i]->nTerm - pNear->nNear;
+        if( pPos->iPos<iMin || pPos->iPos>iMax ){
+          bMatch = 0;
+          while( pPos->iPos<iMin ){
+            if( fts5LookaheadReaderNext(pPos) ) goto ismatch_out;
+          }
+          if( pPos->iPos>iMax ) iMax = pPos->iPos;
+        }
+      }
+    }while( bMatch==0 );
+
+    /* Add an entry to each output position list */
+    for(i=0; i<pNear->nPhrase; i++){
+      i64 iPos = a[i].reader.iPos;
+      Fts5PoslistWriter *pWriter = &a[i].writer;
+      if( a[i].pOut->n==0 || iPos!=pWriter->iPrev ){
+        sqlite3Fts5PoslistWriterAppend(a[i].pOut, pWriter, iPos);
+      }
+    }
+
+    iAdv = 0;
+    iMin = a[0].reader.iLookahead;
+    for(i=0; i<pNear->nPhrase; i++){
+      if( a[i].reader.iLookahead < iMin ){
+        iMin = a[i].reader.iLookahead;
+        iAdv = i;
+      }
+    }
+    if( fts5LookaheadReaderNext(&a[iAdv].reader) ) goto ismatch_out;
+  }
+
+  ismatch_out: {
+    int bRet = a[0].pOut->n>0;
+    *pRc = rc;
+    if( a!=aStatic ) sqlite3_free(a);
+    return bRet;
+  }
+}
+
+/*
+** Advance iterator pIter until it points to a value equal to or laster
+** than the initial value of *piLast. If this means the iterator points
+** to a value laster than *piLast, update *piLast to the new lastest value.
+**
+** If the iterator reaches EOF, set *pbEof to true before returning. If
+** an error occurs, set *pRc to an error code. If either *pbEof or *pRc
+** are set, return a non-zero value. Otherwise, return zero.
+*/
+static int fts5ExprAdvanceto(
+  Fts5IndexIter *pIter,           /* Iterator to advance */
+  int bDesc,                      /* True if iterator is "rowid DESC" */
+  i64 *piLast,                    /* IN/OUT: Lastest rowid seen so far */
+  int *pRc,                       /* OUT: Error code */
+  int *pbEof                      /* OUT: Set to true if EOF */
+){
+  i64 iLast = *piLast;
+  i64 iRowid;
+
+  iRowid = pIter->iRowid;
+  if( (bDesc==0 && iLast>iRowid) || (bDesc && iLast<iRowid) ){
+    int rc = sqlite3Fts5IterNextFrom(pIter, iLast);
+    if( rc || sqlite3Fts5IterEof(pIter) ){
+      *pRc = rc;
+      *pbEof = 1;
+      return 1;
+    }
+    iRowid = pIter->iRowid;
+    assert( (bDesc==0 && iRowid>=iLast) || (bDesc==1 && iRowid<=iLast) );
+  }
+  *piLast = iRowid;
+
+  return 0;
+}
+
+static int fts5ExprSynonymAdvanceto(
+  Fts5ExprTerm *pTerm,            /* Term iterator to advance */
+  int bDesc,                      /* True if iterator is "rowid DESC" */
+  i64 *piLast,                    /* IN/OUT: Lastest rowid seen so far */
+  int *pRc                        /* OUT: Error code */
+){
+  int rc = SQLITE_OK;
+  i64 iLast = *piLast;
+  Fts5ExprTerm *p;
+  int bEof = 0;
+
+  for(p=pTerm; rc==SQLITE_OK && p; p=p->pSynonym){
+    if( sqlite3Fts5IterEof(p->pIter)==0 ){
+      i64 iRowid = p->pIter->iRowid;
+      if( (bDesc==0 && iLast>iRowid) || (bDesc && iLast<iRowid) ){
+        rc = sqlite3Fts5IterNextFrom(p->pIter, iLast);
+      }
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    *pRc = rc;
+    bEof = 1;
+  }else{
+    *piLast = fts5ExprSynonymRowid(pTerm, bDesc, &bEof);
+  }
+  return bEof;
+}
+
+
+static int fts5ExprNearTest(
+  int *pRc,
+  Fts5Expr *pExpr,                /* Expression that pNear is a part of */
+  Fts5ExprNode *pNode             /* The "NEAR" node (FTS5_STRING) */
+){
+  Fts5ExprNearset *pNear = pNode->pNear;
+  int rc = *pRc;
+
+  if( pExpr->pConfig->eDetail!=FTS5_DETAIL_FULL ){
+    Fts5ExprTerm *pTerm;
+    Fts5ExprPhrase *pPhrase = pNear->apPhrase[0];
+    pPhrase->poslist.n = 0;
+    for(pTerm=&pPhrase->aTerm[0]; pTerm; pTerm=pTerm->pSynonym){
+      Fts5IndexIter *pIter = pTerm->pIter;
+      if( sqlite3Fts5IterEof(pIter)==0 ){
+        if( pIter->iRowid==pNode->iRowid && pIter->nData>0 ){
+          pPhrase->poslist.n = 1;
+        }
+      }
+    }
+    return pPhrase->poslist.n;
+  }else{
+    int i;
+
+    /* Check that each phrase in the nearset matches the current row.
+    ** Populate the pPhrase->poslist buffers at the same time. If any
+    ** phrase is not a match, break out of the loop early.  */
+    for(i=0; rc==SQLITE_OK && i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      if( pPhrase->nTerm>1 || pPhrase->aTerm[0].pSynonym
+       || pNear->pColset || pPhrase->aTerm[0].bFirst
+      ){
+        int bMatch = 0;
+        rc = fts5ExprPhraseIsMatch(pNode, pPhrase, &bMatch);
+        if( bMatch==0 ) break;
+      }else{
+        Fts5IndexIter *pIter = pPhrase->aTerm[0].pIter;
+        fts5BufferSet(&rc, &pPhrase->poslist, pIter->nData, pIter->pData);
+      }
+    }
+
+    *pRc = rc;
+    if( i==pNear->nPhrase && (i==1 || fts5ExprNearIsMatch(pRc, pNear)) ){
+      return 1;
+    }
+    return 0;
+  }
+}
+
+
+/*
+** Initialize all term iterators in the pNear object. If any term is found
+** to match no documents at all, return immediately without initializing any
+** further iterators.
+**
+** If an error occurs, return an SQLite error code. Otherwise, return
+** SQLITE_OK. It is not considered an error if some term matches zero
+** documents.
+*/
+static int fts5ExprNearInitAll(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode
+){
+  Fts5ExprNearset *pNear = pNode->pNear;
+  int i;
+
+  assert( pNode->bNomatch==0 );
+  for(i=0; i<pNear->nPhrase; i++){
+    Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+    if( pPhrase->nTerm==0 ){
+      pNode->bEof = 1;
+      return SQLITE_OK;
+    }else{
+      int j;
+      for(j=0; j<pPhrase->nTerm; j++){
+        Fts5ExprTerm *pTerm = &pPhrase->aTerm[j];
+        Fts5ExprTerm *p;
+        int bHit = 0;
+
+        for(p=pTerm; p; p=p->pSynonym){
+          int rc;
+          if( p->pIter ){
+            sqlite3Fts5IterClose(p->pIter);
+            p->pIter = 0;
+          }
+          rc = sqlite3Fts5IndexQuery(
+              pExpr->pIndex, p->pTerm, p->nQueryTerm,
+              (pTerm->bPrefix ? FTS5INDEX_QUERY_PREFIX : 0) |
+              (pExpr->bDesc ? FTS5INDEX_QUERY_DESC : 0),
+              pNear->pColset,
+              &p->pIter
+          );
+          assert( (rc==SQLITE_OK)==(p->pIter!=0) );
+          if( rc!=SQLITE_OK ) return rc;
+          if( 0==sqlite3Fts5IterEof(p->pIter) ){
+            bHit = 1;
+          }
+        }
+
+        if( bHit==0 ){
+          pNode->bEof = 1;
+          return SQLITE_OK;
+        }
+      }
+    }
+  }
+
+  pNode->bEof = 0;
+  return SQLITE_OK;
+}
+
+/*
+** If pExpr is an ASC iterator, this function returns a value with the
+** same sign as:
+**
+**   (iLhs - iRhs)
+**
+** Otherwise, if this is a DESC iterator, the opposite is returned:
+**
+**   (iRhs - iLhs)
+*/
+static int fts5RowidCmp(
+  Fts5Expr *pExpr,
+  i64 iLhs,
+  i64 iRhs
+){
+  assert( pExpr->bDesc==0 || pExpr->bDesc==1 );
+  if( pExpr->bDesc==0 ){
+    if( iLhs<iRhs ) return -1;
+    return (iLhs > iRhs);
+  }else{
+    if( iLhs>iRhs ) return -1;
+    return (iLhs < iRhs);
+  }
+}
+
+static void fts5ExprSetEof(Fts5ExprNode *pNode){
+  int i;
+  pNode->bEof = 1;
+  pNode->bNomatch = 0;
+  for(i=0; i<pNode->nChild; i++){
+    fts5ExprSetEof(pNode->apChild[i]);
+  }
+}
+
+static void fts5ExprNodeZeroPoslist(Fts5ExprNode *pNode){
+  if( pNode->eType==FTS5_STRING || pNode->eType==FTS5_TERM ){
+    Fts5ExprNearset *pNear = pNode->pNear;
+    int i;
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      pPhrase->poslist.n = 0;
+    }
+  }else{
+    int i;
+    for(i=0; i<pNode->nChild; i++){
+      fts5ExprNodeZeroPoslist(pNode->apChild[i]);
+    }
+  }
+}
+
+
+
+/*
+** Compare the values currently indicated by the two nodes as follows:
+**
+**    res = (*p1) - (*p2)
+**
+** Nodes that point to values that come later in the iteration order are
+** considered to be larger. Nodes at EOF are the largest of all.
+**
+** This means that if the iteration order is ASC, then numerically larger
+** rowids are considered larger. Or if it is the default DESC, numerically
+** smaller rowids are larger.
+*/
+static int fts5NodeCompare(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *p1,
+  Fts5ExprNode *p2
+){
+  if( p2->bEof ) return -1;
+  if( p1->bEof ) return +1;
+  return fts5RowidCmp(pExpr, p1->iRowid, p2->iRowid);
+}
+
+/*
+** All individual term iterators in pNear are guaranteed to be valid when
+** this function is called. This function checks if all term iterators
+** point to the same rowid, and if not, advances them until they do.
+** If an EOF is reached before this happens, *pbEof is set to true before
+** returning.
+**
+** SQLITE_OK is returned if an error occurs, or an SQLite error code
+** otherwise. It is not considered an error code if an iterator reaches
+** EOF.
+*/
+static int fts5ExprNodeTest_STRING(
+  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
+  Fts5ExprNode *pNode
+){
+  Fts5ExprNearset *pNear = pNode->pNear;
+  Fts5ExprPhrase *pLeft = pNear->apPhrase[0];
+  int rc = SQLITE_OK;
+  i64 iLast;                      /* Lastest rowid any iterator points to */
+  int i, j;                       /* Phrase and token index, respectively */
+  int bMatch;                     /* True if all terms are at the same rowid */
+  const int bDesc = pExpr->bDesc;
+
+  /* Check that this node should not be FTS5_TERM */
+  assert( pNear->nPhrase>1
+       || pNear->apPhrase[0]->nTerm>1
+       || pNear->apPhrase[0]->aTerm[0].pSynonym
+       || pNear->apPhrase[0]->aTerm[0].bFirst
+  );
+
+  /* Initialize iLast, the "lastest" rowid any iterator points to. If the
+  ** iterator skips through rowids in the default ascending order, this means
+  ** the maximum rowid. Or, if the iterator is "ORDER BY rowid DESC", then it
+  ** means the minimum rowid.  */
+  if( pLeft->aTerm[0].pSynonym ){
+    iLast = fts5ExprSynonymRowid(&pLeft->aTerm[0], bDesc, 0);
+  }else{
+    iLast = pLeft->aTerm[0].pIter->iRowid;
+  }
+
+  do {
+    bMatch = 1;
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      for(j=0; j<pPhrase->nTerm; j++){
+        Fts5ExprTerm *pTerm = &pPhrase->aTerm[j];
+        if( pTerm->pSynonym ){
+          i64 iRowid = fts5ExprSynonymRowid(pTerm, bDesc, 0);
+          if( iRowid==iLast ) continue;
+          bMatch = 0;
+          if( fts5ExprSynonymAdvanceto(pTerm, bDesc, &iLast, &rc) ){
+            pNode->bNomatch = 0;
+            pNode->bEof = 1;
+            return rc;
+          }
+        }else{
+          Fts5IndexIter *pIter = pPhrase->aTerm[j].pIter;
+          if( pIter->iRowid==iLast ) continue;
+          bMatch = 0;
+          if( fts5ExprAdvanceto(pIter, bDesc, &iLast, &rc, &pNode->bEof) ){
+            return rc;
+          }
+        }
+      }
+    }
+  }while( bMatch==0 );
+
+  pNode->iRowid = iLast;
+  pNode->bNomatch = ((0==fts5ExprNearTest(&rc, pExpr, pNode)) && rc==SQLITE_OK);
+  assert( pNode->bEof==0 || pNode->bNomatch==0 );
+
+  return rc;
+}
+
+/*
+** Advance the first term iterator in the first phrase of pNear. Set output
+** variable *pbEof to true if it reaches EOF or if an error occurs.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int fts5ExprNodeNext_STRING(
+  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
+  Fts5ExprNode *pNode,            /* FTS5_STRING or FTS5_TERM node */
+  int bFromValid,
+  i64 iFrom
+){
+  Fts5ExprTerm *pTerm = &pNode->pNear->apPhrase[0]->aTerm[0];
+  int rc = SQLITE_OK;
+
+  pNode->bNomatch = 0;
+  if( pTerm->pSynonym ){
+    int bEof = 1;
+    Fts5ExprTerm *p;
+
+    /* Find the firstest rowid any synonym points to. */
+    i64 iRowid = fts5ExprSynonymRowid(pTerm, pExpr->bDesc, 0);
+
+    /* Advance each iterator that currently points to iRowid. Or, if iFrom
+    ** is valid - each iterator that points to a rowid before iFrom.  */
+    for(p=pTerm; p; p=p->pSynonym){
+      if( sqlite3Fts5IterEof(p->pIter)==0 ){
+        i64 ii = p->pIter->iRowid;
+        if( ii==iRowid
+         || (bFromValid && ii!=iFrom && (ii>iFrom)==pExpr->bDesc)
+        ){
+          if( bFromValid ){
+            rc = sqlite3Fts5IterNextFrom(p->pIter, iFrom);
+          }else{
+            rc = sqlite3Fts5IterNext(p->pIter);
+          }
+          if( rc!=SQLITE_OK ) break;
+          if( sqlite3Fts5IterEof(p->pIter)==0 ){
+            bEof = 0;
+          }
+        }else{
+          bEof = 0;
+        }
+      }
+    }
+
+    /* Set the EOF flag if either all synonym iterators are at EOF or an
+    ** error has occurred.  */
+    pNode->bEof = (rc || bEof);
+  }else{
+    Fts5IndexIter *pIter = pTerm->pIter;
+
+    assert( Fts5NodeIsString(pNode) );
+    if( bFromValid ){
+      rc = sqlite3Fts5IterNextFrom(pIter, iFrom);
+    }else{
+      rc = sqlite3Fts5IterNext(pIter);
+    }
+
+    pNode->bEof = (rc || sqlite3Fts5IterEof(pIter));
+  }
+
+  if( pNode->bEof==0 ){
+    assert( rc==SQLITE_OK );
+    rc = fts5ExprNodeTest_STRING(pExpr, pNode);
+  }
+
+  return rc;
+}
+
+
+static int fts5ExprNodeTest_TERM(
+  Fts5Expr *pExpr,                /* Expression that pNear is a part of */
+  Fts5ExprNode *pNode             /* The "NEAR" node (FTS5_TERM) */
+){
+  /* As this "NEAR" object is actually a single phrase that consists
+  ** of a single term only, grab pointers into the poslist managed by the
+  ** fts5_index.c iterator object. This is much faster than synthesizing
+  ** a new poslist the way we have to for more complicated phrase or NEAR
+  ** expressions.  */
+  Fts5ExprPhrase *pPhrase = pNode->pNear->apPhrase[0];
+  Fts5IndexIter *pIter = pPhrase->aTerm[0].pIter;
+
+  assert( pNode->eType==FTS5_TERM );
+  assert( pNode->pNear->nPhrase==1 && pPhrase->nTerm==1 );
+  assert( pPhrase->aTerm[0].pSynonym==0 );
+
+  pPhrase->poslist.n = pIter->nData;
+  if( pExpr->pConfig->eDetail==FTS5_DETAIL_FULL ){
+    pPhrase->poslist.p = (u8*)pIter->pData;
+  }
+  pNode->iRowid = pIter->iRowid;
+  pNode->bNomatch = (pPhrase->poslist.n==0);
+  return SQLITE_OK;
+}
+
+/*
+** xNext() method for a node of type FTS5_TERM.
+*/
+static int fts5ExprNodeNext_TERM(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode,
+  int bFromValid,
+  i64 iFrom
+){
+  int rc;
+  Fts5IndexIter *pIter = pNode->pNear->apPhrase[0]->aTerm[0].pIter;
+
+  assert( pNode->bEof==0 );
+  if( bFromValid ){
+    rc = sqlite3Fts5IterNextFrom(pIter, iFrom);
+  }else{
+    rc = sqlite3Fts5IterNext(pIter);
+  }
+  if( rc==SQLITE_OK && sqlite3Fts5IterEof(pIter)==0 ){
+    rc = fts5ExprNodeTest_TERM(pExpr, pNode);
+  }else{
+    pNode->bEof = 1;
+    pNode->bNomatch = 0;
+  }
+  return rc;
+}
+
+static void fts5ExprNodeTest_OR(
+  Fts5Expr *pExpr,                /* Expression of which pNode is a part */
+  Fts5ExprNode *pNode             /* Expression node to test */
+){
+  Fts5ExprNode *pNext = pNode->apChild[0];
+  int i;
+
+  for(i=1; i<pNode->nChild; i++){
+    Fts5ExprNode *pChild = pNode->apChild[i];
+    int cmp = fts5NodeCompare(pExpr, pNext, pChild);
+    if( cmp>0 || (cmp==0 && pChild->bNomatch==0) ){
+      pNext = pChild;
+    }
+  }
+  pNode->iRowid = pNext->iRowid;
+  pNode->bEof = pNext->bEof;
+  pNode->bNomatch = pNext->bNomatch;
+}
+
+static int fts5ExprNodeNext_OR(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode,
+  int bFromValid,
+  i64 iFrom
+){
+  int i;
+  i64 iLast = pNode->iRowid;
+
+  for(i=0; i<pNode->nChild; i++){
+    Fts5ExprNode *p1 = pNode->apChild[i];
+    assert( p1->bEof || fts5RowidCmp(pExpr, p1->iRowid, iLast)>=0 );
+    if( p1->bEof==0 ){
+      if( (p1->iRowid==iLast)
+       || (bFromValid && fts5RowidCmp(pExpr, p1->iRowid, iFrom)<0)
+      ){
+        int rc = fts5ExprNodeNext(pExpr, p1, bFromValid, iFrom);
+        if( rc!=SQLITE_OK ){
+          pNode->bNomatch = 0;
+          return rc;
+        }
+      }
+    }
+  }
+
+  fts5ExprNodeTest_OR(pExpr, pNode);
+  return SQLITE_OK;
+}
+
+/*
+** Argument pNode is an FTS5_AND node.
+*/
+static int fts5ExprNodeTest_AND(
+  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
+  Fts5ExprNode *pAnd              /* FTS5_AND node to advance */
+){
+  int iChild;
+  i64 iLast = pAnd->iRowid;
+  int rc = SQLITE_OK;
+  int bMatch;
+
+  assert( pAnd->bEof==0 );
+  do {
+    pAnd->bNomatch = 0;
+    bMatch = 1;
+    for(iChild=0; iChild<pAnd->nChild; iChild++){
+      Fts5ExprNode *pChild = pAnd->apChild[iChild];
+      int cmp = fts5RowidCmp(pExpr, iLast, pChild->iRowid);
+      if( cmp>0 ){
+        /* Advance pChild until it points to iLast or laster */
+        rc = fts5ExprNodeNext(pExpr, pChild, 1, iLast);
+        if( rc!=SQLITE_OK ){
+          pAnd->bNomatch = 0;
+          return rc;
+        }
+      }
+
+      /* If the child node is now at EOF, so is the parent AND node. Otherwise,
+      ** the child node is guaranteed to have advanced at least as far as
+      ** rowid iLast. So if it is not at exactly iLast, pChild->iRowid is the
+      ** new lastest rowid seen so far.  */
+      assert( pChild->bEof || fts5RowidCmp(pExpr, iLast, pChild->iRowid)<=0 );
+      if( pChild->bEof ){
+        fts5ExprSetEof(pAnd);
+        bMatch = 1;
+        break;
+      }else if( iLast!=pChild->iRowid ){
+        bMatch = 0;
+        iLast = pChild->iRowid;
+      }
+
+      if( pChild->bNomatch ){
+        pAnd->bNomatch = 1;
+      }
+    }
+  }while( bMatch==0 );
+
+  if( pAnd->bNomatch && pAnd!=pExpr->pRoot ){
+    fts5ExprNodeZeroPoslist(pAnd);
+  }
+  pAnd->iRowid = iLast;
+  return SQLITE_OK;
+}
+
+static int fts5ExprNodeNext_AND(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode,
+  int bFromValid,
+  i64 iFrom
+){
+  int rc = fts5ExprNodeNext(pExpr, pNode->apChild[0], bFromValid, iFrom);
+  if( rc==SQLITE_OK ){
+    rc = fts5ExprNodeTest_AND(pExpr, pNode);
+  }else{
+    pNode->bNomatch = 0;
+  }
+  return rc;
+}
+
+static int fts5ExprNodeTest_NOT(
+  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
+  Fts5ExprNode *pNode             /* FTS5_NOT node to advance */
+){
+  int rc = SQLITE_OK;
+  Fts5ExprNode *p1 = pNode->apChild[0];
+  Fts5ExprNode *p2 = pNode->apChild[1];
+  assert( pNode->nChild==2 );
+
+  while( rc==SQLITE_OK && p1->bEof==0 ){
+    int cmp = fts5NodeCompare(pExpr, p1, p2);
+    if( cmp>0 ){
+      rc = fts5ExprNodeNext(pExpr, p2, 1, p1->iRowid);
+      cmp = fts5NodeCompare(pExpr, p1, p2);
+    }
+    assert( rc!=SQLITE_OK || cmp<=0 );
+    if( cmp || p2->bNomatch ) break;
+    rc = fts5ExprNodeNext(pExpr, p1, 0, 0);
+  }
+  pNode->bEof = p1->bEof;
+  pNode->bNomatch = p1->bNomatch;
+  pNode->iRowid = p1->iRowid;
+  if( p1->bEof ){
+    fts5ExprNodeZeroPoslist(p2);
+  }
+  return rc;
+}
+
+static int fts5ExprNodeNext_NOT(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode,
+  int bFromValid,
+  i64 iFrom
+){
+  int rc = fts5ExprNodeNext(pExpr, pNode->apChild[0], bFromValid, iFrom);
+  if( rc==SQLITE_OK ){
+    rc = fts5ExprNodeTest_NOT(pExpr, pNode);
+  }
+  if( rc!=SQLITE_OK ){
+    pNode->bNomatch = 0;
+  }
+  return rc;
+}
+
+/*
+** If pNode currently points to a match, this function returns SQLITE_OK
+** without modifying it. Otherwise, pNode is advanced until it does point
+** to a match or EOF is reached.
+*/
+static int fts5ExprNodeTest(
+  Fts5Expr *pExpr,                /* Expression of which pNode is a part */
+  Fts5ExprNode *pNode             /* Expression node to test */
+){
+  int rc = SQLITE_OK;
+  if( pNode->bEof==0 ){
+    switch( pNode->eType ){
+
+      case FTS5_STRING: {
+        rc = fts5ExprNodeTest_STRING(pExpr, pNode);
+        break;
+      }
+
+      case FTS5_TERM: {
+        rc = fts5ExprNodeTest_TERM(pExpr, pNode);
+        break;
+      }
+
+      case FTS5_AND: {
+        rc = fts5ExprNodeTest_AND(pExpr, pNode);
+        break;
+      }
+
+      case FTS5_OR: {
+        fts5ExprNodeTest_OR(pExpr, pNode);
+        break;
+      }
+
+      default: assert( pNode->eType==FTS5_NOT ); {
+        rc = fts5ExprNodeTest_NOT(pExpr, pNode);
+        break;
+      }
+    }
+  }
+  return rc;
+}
+
+
+/*
+** Set node pNode, which is part of expression pExpr, to point to the first
+** match. If there are no matches, set the Node.bEof flag to indicate EOF.
+**
+** Return an SQLite error code if an error occurs, or SQLITE_OK otherwise.
+** It is not an error if there are no matches.
+*/
+static int fts5ExprNodeFirst(Fts5Expr *pExpr, Fts5ExprNode *pNode){
+  int rc = SQLITE_OK;
+  pNode->bEof = 0;
+  pNode->bNomatch = 0;
+
+  if( Fts5NodeIsString(pNode) ){
+    /* Initialize all term iterators in the NEAR object. */
+    rc = fts5ExprNearInitAll(pExpr, pNode);
+  }else if( pNode->xNext==0 ){
+    pNode->bEof = 1;
+  }else{
+    int i;
+    int nEof = 0;
+    for(i=0; i<pNode->nChild && rc==SQLITE_OK; i++){
+      Fts5ExprNode *pChild = pNode->apChild[i];
+      rc = fts5ExprNodeFirst(pExpr, pNode->apChild[i]);
+      assert( pChild->bEof==0 || pChild->bEof==1 );
+      nEof += pChild->bEof;
+    }
+    pNode->iRowid = pNode->apChild[0]->iRowid;
+
+    switch( pNode->eType ){
+      case FTS5_AND:
+        if( nEof>0 ) fts5ExprSetEof(pNode);
+        break;
+
+      case FTS5_OR:
+        if( pNode->nChild==nEof ) fts5ExprSetEof(pNode);
+        break;
+
+      default:
+        assert( pNode->eType==FTS5_NOT );
+        pNode->bEof = pNode->apChild[0]->bEof;
+        break;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts5ExprNodeTest(pExpr, pNode);
+  }
+  return rc;
+}
+
+
+/*
+** Begin iterating through the set of documents in index pIdx matched by
+** the MATCH expression passed as the first argument. If the "bDesc"
+** parameter is passed a non-zero value, iteration is in descending rowid
+** order. Or, if it is zero, in ascending order.
+**
+** If iterating in ascending rowid order (bDesc==0), the first document
+** visited is that with the smallest rowid that is larger than or equal
+** to parameter iFirst. Or, if iterating in ascending order (bDesc==1),
+** then the first document visited must have a rowid smaller than or
+** equal to iFirst.
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise. It
+** is not considered an error if the query does not match any documents.
+*/
+static int sqlite3Fts5ExprFirst(Fts5Expr *p, Fts5Index *pIdx, i64 iFirst, int bDesc){
+  Fts5ExprNode *pRoot = p->pRoot;
+  int rc;                         /* Return code */
+
+  p->pIndex = pIdx;
+  p->bDesc = bDesc;
+  rc = fts5ExprNodeFirst(p, pRoot);
+
+  /* If not at EOF but the current rowid occurs earlier than iFirst in
+  ** the iteration order, move to document iFirst or later. */
+  if( rc==SQLITE_OK
+   && 0==pRoot->bEof
+   && fts5RowidCmp(p, pRoot->iRowid, iFirst)<0
+  ){
+    rc = fts5ExprNodeNext(p, pRoot, 1, iFirst);
+  }
+
+  /* If the iterator is not at a real match, skip forward until it is. */
+  while( pRoot->bNomatch && rc==SQLITE_OK ){
+    assert( pRoot->bEof==0 );
+    rc = fts5ExprNodeNext(p, pRoot, 0, 0);
+  }
+  return rc;
+}
+
+/*
+** Move to the next document
+**
+** Return SQLITE_OK if successful, or an SQLite error code otherwise. It
+** is not considered an error if the query does not match any documents.
+*/
+static int sqlite3Fts5ExprNext(Fts5Expr *p, i64 iLast){
+  int rc;
+  Fts5ExprNode *pRoot = p->pRoot;
+  assert( pRoot->bEof==0 && pRoot->bNomatch==0 );
+  do {
+    rc = fts5ExprNodeNext(p, pRoot, 0, 0);
+    assert( pRoot->bNomatch==0 || (rc==SQLITE_OK && pRoot->bEof==0) );
+  }while( pRoot->bNomatch );
+  if( fts5RowidCmp(p, pRoot->iRowid, iLast)>0 ){
+    pRoot->bEof = 1;
+  }
+  return rc;
+}
+
+static int sqlite3Fts5ExprEof(Fts5Expr *p){
+  return p->pRoot->bEof;
+}
+
+static i64 sqlite3Fts5ExprRowid(Fts5Expr *p){
+  return p->pRoot->iRowid;
+}
+
+static int fts5ParseStringFromToken(Fts5Token *pToken, char **pz){
+  int rc = SQLITE_OK;
+  *pz = sqlite3Fts5Strndup(&rc, pToken->p, pToken->n);
+  return rc;
+}
+
+/*
+** Free the phrase object passed as the only argument.
+*/
+static void fts5ExprPhraseFree(Fts5ExprPhrase *pPhrase){
+  if( pPhrase ){
+    int i;
+    for(i=0; i<pPhrase->nTerm; i++){
+      Fts5ExprTerm *pSyn;
+      Fts5ExprTerm *pNext;
+      Fts5ExprTerm *pTerm = &pPhrase->aTerm[i];
+      sqlite3_free(pTerm->pTerm);
+      sqlite3Fts5IterClose(pTerm->pIter);
+      for(pSyn=pTerm->pSynonym; pSyn; pSyn=pNext){
+        pNext = pSyn->pSynonym;
+        sqlite3Fts5IterClose(pSyn->pIter);
+        fts5BufferFree((Fts5Buffer*)&pSyn[1]);
+        sqlite3_free(pSyn);
+      }
+    }
+    if( pPhrase->poslist.nSpace>0 ) fts5BufferFree(&pPhrase->poslist);
+    sqlite3_free(pPhrase);
+  }
+}
+
+/*
+** Set the "bFirst" flag on the first token of the phrase passed as the
+** only argument.
+*/
+static void sqlite3Fts5ParseSetCaret(Fts5ExprPhrase *pPhrase){
+  if( pPhrase && pPhrase->nTerm ){
+    pPhrase->aTerm[0].bFirst = 1;
+  }
+}
+
+/*
+** If argument pNear is NULL, then a new Fts5ExprNearset object is allocated
+** and populated with pPhrase. Or, if pNear is not NULL, phrase pPhrase is
+** appended to it and the results returned.
+**
+** If an OOM error occurs, both the pNear and pPhrase objects are freed and
+** NULL returned.
+*/
+static Fts5ExprNearset *sqlite3Fts5ParseNearset(
+  Fts5Parse *pParse,              /* Parse context */
+  Fts5ExprNearset *pNear,         /* Existing nearset, or NULL */
+  Fts5ExprPhrase *pPhrase         /* Recently parsed phrase */
+){
+  const int SZALLOC = 8;
+  Fts5ExprNearset *pRet = 0;
+
+  if( pParse->rc==SQLITE_OK ){
+    if( pNear==0 ){
+      sqlite3_int64 nByte;
+      nByte = sizeof(Fts5ExprNearset) + SZALLOC * sizeof(Fts5ExprPhrase*);
+      pRet = sqlite3_malloc64(nByte);
+      if( pRet==0 ){
+        pParse->rc = SQLITE_NOMEM;
+      }else{
+        memset(pRet, 0, (size_t)nByte);
+      }
+    }else if( (pNear->nPhrase % SZALLOC)==0 ){
+      int nNew = pNear->nPhrase + SZALLOC;
+      sqlite3_int64 nByte;
+
+      nByte = sizeof(Fts5ExprNearset) + nNew * sizeof(Fts5ExprPhrase*);
+      pRet = (Fts5ExprNearset*)sqlite3_realloc64(pNear, nByte);
+      if( pRet==0 ){
+        pParse->rc = SQLITE_NOMEM;
+      }
+    }else{
+      pRet = pNear;
+    }
+  }
+
+  if( pRet==0 ){
+    assert( pParse->rc!=SQLITE_OK );
+    sqlite3Fts5ParseNearsetFree(pNear);
+    sqlite3Fts5ParsePhraseFree(pPhrase);
+  }else{
+    if( pRet->nPhrase>0 ){
+      Fts5ExprPhrase *pLast = pRet->apPhrase[pRet->nPhrase-1];
+      assert( pParse!=0 );
+      assert( pParse->apPhrase!=0 );
+      assert( pParse->nPhrase>=2 );
+      assert( pLast==pParse->apPhrase[pParse->nPhrase-2] );
+      if( pPhrase->nTerm==0 ){
+        fts5ExprPhraseFree(pPhrase);
+        pRet->nPhrase--;
+        pParse->nPhrase--;
+        pPhrase = pLast;
+      }else if( pLast->nTerm==0 ){
+        fts5ExprPhraseFree(pLast);
+        pParse->apPhrase[pParse->nPhrase-2] = pPhrase;
+        pParse->nPhrase--;
+        pRet->nPhrase--;
+      }
+    }
+    pRet->apPhrase[pRet->nPhrase++] = pPhrase;
+  }
+  return pRet;
+}
+
+typedef struct TokenCtx TokenCtx;
+struct TokenCtx {
+  Fts5ExprPhrase *pPhrase;
+  Fts5Config *pConfig;
+  int rc;
+};
+
+/*
+** Callback for tokenizing terms used by ParseTerm().
+*/
+static int fts5ParseTokenize(
+  void *pContext,                 /* Pointer to Fts5InsertCtx object */
+  int tflags,                     /* Mask of FTS5_TOKEN_* flags */
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iUnused1,                   /* Start offset of token */
+  int iUnused2                    /* End offset of token */
+){
+  int rc = SQLITE_OK;
+  const int SZALLOC = 8;
+  TokenCtx *pCtx = (TokenCtx*)pContext;
+  Fts5ExprPhrase *pPhrase = pCtx->pPhrase;
+
+  UNUSED_PARAM2(iUnused1, iUnused2);
+
+  /* If an error has already occurred, this is a no-op */
+  if( pCtx->rc!=SQLITE_OK ) return pCtx->rc;
+  if( nToken>FTS5_MAX_TOKEN_SIZE ) nToken = FTS5_MAX_TOKEN_SIZE;
+
+  if( pPhrase && pPhrase->nTerm>0 && (tflags & FTS5_TOKEN_COLOCATED) ){
+    Fts5ExprTerm *pSyn;
+    sqlite3_int64 nByte = sizeof(Fts5ExprTerm) + sizeof(Fts5Buffer) + nToken+1;
+    pSyn = (Fts5ExprTerm*)sqlite3_malloc64(nByte);
+    if( pSyn==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pSyn, 0, (size_t)nByte);
+      pSyn->pTerm = ((char*)pSyn) + sizeof(Fts5ExprTerm) + sizeof(Fts5Buffer);
+      pSyn->nFullTerm = pSyn->nQueryTerm = nToken;
+      if( pCtx->pConfig->bTokendata ){
+        pSyn->nQueryTerm = (int)strlen(pSyn->pTerm);
+      }
+      memcpy(pSyn->pTerm, pToken, nToken);
+      pSyn->pSynonym = pPhrase->aTerm[pPhrase->nTerm-1].pSynonym;
+      pPhrase->aTerm[pPhrase->nTerm-1].pSynonym = pSyn;
+    }
+  }else{
+    Fts5ExprTerm *pTerm;
+    if( pPhrase==0 || (pPhrase->nTerm % SZALLOC)==0 ){
+      Fts5ExprPhrase *pNew;
+      int nNew = SZALLOC + (pPhrase ? pPhrase->nTerm : 0);
+
+      pNew = (Fts5ExprPhrase*)sqlite3_realloc64(pPhrase,
+          sizeof(Fts5ExprPhrase) + sizeof(Fts5ExprTerm) * nNew
+      );
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        if( pPhrase==0 ) memset(pNew, 0, sizeof(Fts5ExprPhrase));
+        pCtx->pPhrase = pPhrase = pNew;
+        pNew->nTerm = nNew - SZALLOC;
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      pTerm = &pPhrase->aTerm[pPhrase->nTerm++];
+      memset(pTerm, 0, sizeof(Fts5ExprTerm));
+      pTerm->pTerm = sqlite3Fts5Strndup(&rc, pToken, nToken);
+      pTerm->nFullTerm = pTerm->nQueryTerm = nToken;
+      if( pCtx->pConfig->bTokendata && rc==SQLITE_OK ){
+        pTerm->nQueryTerm = (int)strlen(pTerm->pTerm);
+      }
+    }
+  }
+
+  pCtx->rc = rc;
+  return rc;
+}
+
+
+/*
+** Free the phrase object passed as the only argument.
+*/
+static void sqlite3Fts5ParsePhraseFree(Fts5ExprPhrase *pPhrase){
+  fts5ExprPhraseFree(pPhrase);
+}
+
+/*
+** Free the phrase object passed as the second argument.
+*/
+static void sqlite3Fts5ParseNearsetFree(Fts5ExprNearset *pNear){
+  if( pNear ){
+    int i;
+    for(i=0; i<pNear->nPhrase; i++){
+      fts5ExprPhraseFree(pNear->apPhrase[i]);
+    }
+    sqlite3_free(pNear->pColset);
+    sqlite3_free(pNear);
+  }
+}
+
+static void sqlite3Fts5ParseFinished(Fts5Parse *pParse, Fts5ExprNode *p){
+  assert( pParse->pExpr==0 );
+  pParse->pExpr = p;
+}
+
+static int parseGrowPhraseArray(Fts5Parse *pParse){
+  if( (pParse->nPhrase % 8)==0 ){
+    sqlite3_int64 nByte = sizeof(Fts5ExprPhrase*) * (pParse->nPhrase + 8);
+    Fts5ExprPhrase **apNew;
+    apNew = (Fts5ExprPhrase**)sqlite3_realloc64(pParse->apPhrase, nByte);
+    if( apNew==0 ){
+      pParse->rc = SQLITE_NOMEM;
+      return SQLITE_NOMEM;
+    }
+    pParse->apPhrase = apNew;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** This function is called by the parser to process a string token. The
+** string may or may not be quoted. In any case it is tokenized and a
+** phrase object consisting of all tokens returned.
+*/
+static Fts5ExprPhrase *sqlite3Fts5ParseTerm(
+  Fts5Parse *pParse,              /* Parse context */
+  Fts5ExprPhrase *pAppend,        /* Phrase to append to */
+  Fts5Token *pToken,              /* String to tokenize */
+  int bPrefix                     /* True if there is a trailing "*" */
+){
+  Fts5Config *pConfig = pParse->pConfig;
+  TokenCtx sCtx;                  /* Context object passed to callback */
+  int rc;                         /* Tokenize return code */
+  char *z = 0;
+
+  memset(&sCtx, 0, sizeof(TokenCtx));
+  sCtx.pPhrase = pAppend;
+  sCtx.pConfig = pConfig;
+
+  rc = fts5ParseStringFromToken(pToken, &z);
+  if( rc==SQLITE_OK ){
+    int flags = FTS5_TOKENIZE_QUERY | (bPrefix ? FTS5_TOKENIZE_PREFIX : 0);
+    int n;
+    sqlite3Fts5Dequote(z);
+    n = (int)strlen(z);
+    rc = sqlite3Fts5Tokenize(pConfig, flags, z, n, &sCtx, fts5ParseTokenize);
+  }
+  sqlite3_free(z);
+  if( rc || (rc = sCtx.rc) ){
+    pParse->rc = rc;
+    fts5ExprPhraseFree(sCtx.pPhrase);
+    sCtx.pPhrase = 0;
+  }else{
+
+    if( pAppend==0 ){
+      if( parseGrowPhraseArray(pParse) ){
+        fts5ExprPhraseFree(sCtx.pPhrase);
+        return 0;
+      }
+      pParse->nPhrase++;
+    }
+
+    if( sCtx.pPhrase==0 ){
+      /* This happens when parsing a token or quoted phrase that contains
+      ** no token characters at all. (e.g ... MATCH '""'). */
+      sCtx.pPhrase = sqlite3Fts5MallocZero(&pParse->rc, sizeof(Fts5ExprPhrase));
+    }else if( sCtx.pPhrase->nTerm ){
+      sCtx.pPhrase->aTerm[sCtx.pPhrase->nTerm-1].bPrefix = (u8)bPrefix;
+    }
+    assert( pParse->apPhrase!=0 );
+    pParse->apPhrase[pParse->nPhrase-1] = sCtx.pPhrase;
+  }
+
+  return sCtx.pPhrase;
+}
+
+/*
+** Create a new FTS5 expression by cloning phrase iPhrase of the
+** expression passed as the second argument.
+*/
+static int sqlite3Fts5ExprClonePhrase(
+  Fts5Expr *pExpr,
+  int iPhrase,
+  Fts5Expr **ppNew
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5ExprPhrase *pOrig = 0;      /* The phrase extracted from pExpr */
+  Fts5Expr *pNew = 0;             /* Expression to return via *ppNew */
+  TokenCtx sCtx = {0,0,0};        /* Context object for fts5ParseTokenize */
+  if( !pExpr || iPhrase<0 || iPhrase>=pExpr->nPhrase ){
+    rc = SQLITE_RANGE;
+  }else{
+    pOrig = pExpr->apExprPhrase[iPhrase];
+    pNew = (Fts5Expr*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Expr));
+  }
+  if( rc==SQLITE_OK ){
+    pNew->apExprPhrase = (Fts5ExprPhrase**)sqlite3Fts5MallocZero(&rc,
+        sizeof(Fts5ExprPhrase*));
+  }
+  if( rc==SQLITE_OK ){
+    pNew->pRoot = (Fts5ExprNode*)sqlite3Fts5MallocZero(&rc,
+        sizeof(Fts5ExprNode));
+  }
+  if( rc==SQLITE_OK ){
+    pNew->pRoot->pNear = (Fts5ExprNearset*)sqlite3Fts5MallocZero(&rc,
+        sizeof(Fts5ExprNearset) + sizeof(Fts5ExprPhrase*));
+  }
+  if( rc==SQLITE_OK && ALWAYS(pOrig!=0) ){
+    Fts5Colset *pColsetOrig = pOrig->pNode->pNear->pColset;
+    if( pColsetOrig ){
+      sqlite3_int64 nByte;
+      Fts5Colset *pColset;
+      nByte = sizeof(Fts5Colset) + (pColsetOrig->nCol-1) * sizeof(int);
+      pColset = (Fts5Colset*)sqlite3Fts5MallocZero(&rc, nByte);
+      if( pColset ){
+        memcpy(pColset, pColsetOrig, (size_t)nByte);
+      }
+      pNew->pRoot->pNear->pColset = pColset;
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    if( pOrig->nTerm ){
+      int i;                          /* Used to iterate through phrase terms */
+      sCtx.pConfig = pExpr->pConfig;
+      for(i=0; rc==SQLITE_OK && i<pOrig->nTerm; i++){
+        int tflags = 0;
+        Fts5ExprTerm *p;
+        for(p=&pOrig->aTerm[i]; p && rc==SQLITE_OK; p=p->pSynonym){
+          rc = fts5ParseTokenize((void*)&sCtx,tflags,p->pTerm,p->nFullTerm,0,0);
+          tflags = FTS5_TOKEN_COLOCATED;
+        }
+        if( rc==SQLITE_OK ){
+          sCtx.pPhrase->aTerm[i].bPrefix = pOrig->aTerm[i].bPrefix;
+          sCtx.pPhrase->aTerm[i].bFirst = pOrig->aTerm[i].bFirst;
+        }
+      }
+    }else{
+      /* This happens when parsing a token or quoted phrase that contains
+      ** no token characters at all. (e.g ... MATCH '""'). */
+      sCtx.pPhrase = sqlite3Fts5MallocZero(&rc, sizeof(Fts5ExprPhrase));
+    }
+  }
+
+  if( rc==SQLITE_OK && ALWAYS(sCtx.pPhrase) ){
+    /* All the allocations succeeded. Put the expression object together. */
+    pNew->pIndex = pExpr->pIndex;
+    pNew->pConfig = pExpr->pConfig;
+    pNew->nPhrase = 1;
+    pNew->apExprPhrase[0] = sCtx.pPhrase;
+    pNew->pRoot->pNear->apPhrase[0] = sCtx.pPhrase;
+    pNew->pRoot->pNear->nPhrase = 1;
+    sCtx.pPhrase->pNode = pNew->pRoot;
+
+    if( pOrig->nTerm==1
+     && pOrig->aTerm[0].pSynonym==0
+     && pOrig->aTerm[0].bFirst==0
+    ){
+      pNew->pRoot->eType = FTS5_TERM;
+      pNew->pRoot->xNext = fts5ExprNodeNext_TERM;
+    }else{
+      pNew->pRoot->eType = FTS5_STRING;
+      pNew->pRoot->xNext = fts5ExprNodeNext_STRING;
+    }
+  }else{
+    sqlite3Fts5ExprFree(pNew);
+    fts5ExprPhraseFree(sCtx.pPhrase);
+    pNew = 0;
+  }
+
+  *ppNew = pNew;
+  return rc;
+}
+
+
+/*
+** Token pTok has appeared in a MATCH expression where the NEAR operator
+** is expected. If token pTok does not contain "NEAR", store an error
+** in the pParse object.
+*/
+static void sqlite3Fts5ParseNear(Fts5Parse *pParse, Fts5Token *pTok){
+  if( pTok->n!=4 || memcmp("NEAR", pTok->p, 4) ){
+    sqlite3Fts5ParseError(
+        pParse, "fts5: syntax error near \"%.*s\"", pTok->n, pTok->p
+    );
+  }
+}
+
+static void sqlite3Fts5ParseSetDistance(
+  Fts5Parse *pParse,
+  Fts5ExprNearset *pNear,
+  Fts5Token *p
+){
+  if( pNear ){
+    int nNear = 0;
+    int i;
+    if( p->n ){
+      for(i=0; i<p->n; i++){
+        char c = (char)p->p[i];
+        if( c<'0' || c>'9' ){
+          sqlite3Fts5ParseError(
+              pParse, "expected integer, got \"%.*s\"", p->n, p->p
+              );
+          return;
+        }
+        nNear = nNear * 10 + (p->p[i] - '0');
+      }
+    }else{
+      nNear = FTS5_DEFAULT_NEARDIST;
+    }
+    pNear->nNear = nNear;
+  }
+}
+
+/*
+** The second argument passed to this function may be NULL, or it may be
+** an existing Fts5Colset object. This function returns a pointer to
+** a new colset object containing the contents of (p) with new value column
+** number iCol appended.
+**
+** If an OOM error occurs, store an error code in pParse and return NULL.
+** The old colset object (if any) is not freed in this case.
+*/
+static Fts5Colset *fts5ParseColset(
+  Fts5Parse *pParse,              /* Store SQLITE_NOMEM here if required */
+  Fts5Colset *p,                  /* Existing colset object */
+  int iCol                        /* New column to add to colset object */
+){
+  int nCol = p ? p->nCol : 0;     /* Num. columns already in colset object */
+  Fts5Colset *pNew;               /* New colset object to return */
+
+  assert( pParse->rc==SQLITE_OK );
+  assert( iCol>=0 && iCol<pParse->pConfig->nCol );
+
+  pNew = sqlite3_realloc64(p, sizeof(Fts5Colset) + sizeof(int)*nCol);
+  if( pNew==0 ){
+    pParse->rc = SQLITE_NOMEM;
+  }else{
+    int *aiCol = pNew->aiCol;
+    int i, j;
+    for(i=0; i<nCol; i++){
+      if( aiCol[i]==iCol ) return pNew;
+      if( aiCol[i]>iCol ) break;
+    }
+    for(j=nCol; j>i; j--){
+      aiCol[j] = aiCol[j-1];
+    }
+    aiCol[i] = iCol;
+    pNew->nCol = nCol+1;
+
+#ifndef NDEBUG
+    /* Check that the array is in order and contains no duplicate entries. */
+    for(i=1; i<pNew->nCol; i++) assert( pNew->aiCol[i]>pNew->aiCol[i-1] );
+#endif
+  }
+
+  return pNew;
+}
+
+/*
+** Allocate and return an Fts5Colset object specifying the inverse of
+** the colset passed as the second argument. Free the colset passed
+** as the second argument before returning.
+*/
+static Fts5Colset *sqlite3Fts5ParseColsetInvert(Fts5Parse *pParse, Fts5Colset *p){
+  Fts5Colset *pRet;
+  int nCol = pParse->pConfig->nCol;
+
+  pRet = (Fts5Colset*)sqlite3Fts5MallocZero(&pParse->rc,
+      sizeof(Fts5Colset) + sizeof(int)*nCol
+  );
+  if( pRet ){
+    int i;
+    int iOld = 0;
+    for(i=0; i<nCol; i++){
+      if( iOld>=p->nCol || p->aiCol[iOld]!=i ){
+        pRet->aiCol[pRet->nCol++] = i;
+      }else{
+        iOld++;
+      }
+    }
+  }
+
+  sqlite3_free(p);
+  return pRet;
+}
+
+static Fts5Colset *sqlite3Fts5ParseColset(
+  Fts5Parse *pParse,              /* Store SQLITE_NOMEM here if required */
+  Fts5Colset *pColset,            /* Existing colset object */
+  Fts5Token *p
+){
+  Fts5Colset *pRet = 0;
+  int iCol;
+  char *z;                        /* Dequoted copy of token p */
+
+  z = sqlite3Fts5Strndup(&pParse->rc, p->p, p->n);
+  if( pParse->rc==SQLITE_OK ){
+    Fts5Config *pConfig = pParse->pConfig;
+    sqlite3Fts5Dequote(z);
+    for(iCol=0; iCol<pConfig->nCol; iCol++){
+      if( 0==sqlite3_stricmp(pConfig->azCol[iCol], z) ) break;
+    }
+    if( iCol==pConfig->nCol ){
+      sqlite3Fts5ParseError(pParse, "no such column: %s", z);
+    }else{
+      pRet = fts5ParseColset(pParse, pColset, iCol);
+    }
+    sqlite3_free(z);
+  }
+
+  if( pRet==0 ){
+    assert( pParse->rc!=SQLITE_OK );
+    sqlite3_free(pColset);
+  }
+
+  return pRet;
+}
+
+/*
+** If argument pOrig is NULL, or if (*pRc) is set to anything other than
+** SQLITE_OK when this function is called, NULL is returned.
+**
+** Otherwise, a copy of (*pOrig) is made into memory obtained from
+** sqlite3Fts5MallocZero() and a pointer to it returned. If the allocation
+** fails, (*pRc) is set to SQLITE_NOMEM and NULL is returned.
+*/
+static Fts5Colset *fts5CloneColset(int *pRc, Fts5Colset *pOrig){
+  Fts5Colset *pRet;
+  if( pOrig ){
+    sqlite3_int64 nByte = sizeof(Fts5Colset) + (pOrig->nCol-1) * sizeof(int);
+    pRet = (Fts5Colset*)sqlite3Fts5MallocZero(pRc, nByte);
+    if( pRet ){
+      memcpy(pRet, pOrig, (size_t)nByte);
+    }
+  }else{
+    pRet = 0;
+  }
+  return pRet;
+}
+
+/*
+** Remove from colset pColset any columns that are not also in colset pMerge.
+*/
+static void fts5MergeColset(Fts5Colset *pColset, Fts5Colset *pMerge){
+  int iIn = 0;          /* Next input in pColset */
+  int iMerge = 0;       /* Next input in pMerge */
+  int iOut = 0;         /* Next output slot in pColset */
+
+  while( iIn<pColset->nCol && iMerge<pMerge->nCol ){
+    int iDiff = pColset->aiCol[iIn] - pMerge->aiCol[iMerge];
+    if( iDiff==0 ){
+      pColset->aiCol[iOut++] = pMerge->aiCol[iMerge];
+      iMerge++;
+      iIn++;
+    }else if( iDiff>0 ){
+      iMerge++;
+    }else{
+      iIn++;
+    }
+  }
+  pColset->nCol = iOut;
+}
+
+/*
+** Recursively apply colset pColset to expression node pNode and all of
+** its decendents. If (*ppFree) is not NULL, it contains a spare copy
+** of pColset. This function may use the spare copy and set (*ppFree) to
+** zero, or it may create copies of pColset using fts5CloneColset().
+*/
+static void fts5ParseSetColset(
+  Fts5Parse *pParse,
+  Fts5ExprNode *pNode,
+  Fts5Colset *pColset,
+  Fts5Colset **ppFree
+){
+  if( pParse->rc==SQLITE_OK ){
+    assert( pNode->eType==FTS5_TERM || pNode->eType==FTS5_STRING
+         || pNode->eType==FTS5_AND  || pNode->eType==FTS5_OR
+         || pNode->eType==FTS5_NOT  || pNode->eType==FTS5_EOF
+    );
+    if( pNode->eType==FTS5_STRING || pNode->eType==FTS5_TERM ){
+      Fts5ExprNearset *pNear = pNode->pNear;
+      if( pNear->pColset ){
+        fts5MergeColset(pNear->pColset, pColset);
+        if( pNear->pColset->nCol==0 ){
+          pNode->eType = FTS5_EOF;
+          pNode->xNext = 0;
+        }
+      }else if( *ppFree ){
+        pNear->pColset = pColset;
+        *ppFree = 0;
+      }else{
+        pNear->pColset = fts5CloneColset(&pParse->rc, pColset);
+      }
+    }else{
+      int i;
+      assert( pNode->eType!=FTS5_EOF || pNode->nChild==0 );
+      for(i=0; i<pNode->nChild; i++){
+        fts5ParseSetColset(pParse, pNode->apChild[i], pColset, ppFree);
+      }
+    }
+  }
+}
+
+/*
+** Apply colset pColset to expression node pExpr and all of its descendents.
+*/
+static void sqlite3Fts5ParseSetColset(
+  Fts5Parse *pParse,
+  Fts5ExprNode *pExpr,
+  Fts5Colset *pColset
+){
+  Fts5Colset *pFree = pColset;
+  if( pParse->pConfig->eDetail==FTS5_DETAIL_NONE ){
+    sqlite3Fts5ParseError(pParse,
+        "fts5: column queries are not supported (detail=none)"
+    );
+  }else{
+    fts5ParseSetColset(pParse, pExpr, pColset, &pFree);
+  }
+  sqlite3_free(pFree);
+}
+
+static void fts5ExprAssignXNext(Fts5ExprNode *pNode){
+  switch( pNode->eType ){
+    case FTS5_STRING: {
+      Fts5ExprNearset *pNear = pNode->pNear;
+      if( pNear->nPhrase==1 && pNear->apPhrase[0]->nTerm==1
+       && pNear->apPhrase[0]->aTerm[0].pSynonym==0
+       && pNear->apPhrase[0]->aTerm[0].bFirst==0
+      ){
+        pNode->eType = FTS5_TERM;
+        pNode->xNext = fts5ExprNodeNext_TERM;
+      }else{
+        pNode->xNext = fts5ExprNodeNext_STRING;
+      }
+      break;
+    };
+
+    case FTS5_OR: {
+      pNode->xNext = fts5ExprNodeNext_OR;
+      break;
+    };
+
+    case FTS5_AND: {
+      pNode->xNext = fts5ExprNodeNext_AND;
+      break;
+    };
+
+    default: assert( pNode->eType==FTS5_NOT ); {
+      pNode->xNext = fts5ExprNodeNext_NOT;
+      break;
+    };
+  }
+}
+
+/*
+** Add pSub as a child of p.
+*/
+static void fts5ExprAddChildren(Fts5ExprNode *p, Fts5ExprNode *pSub){
+  int ii = p->nChild;
+  if( p->eType!=FTS5_NOT && pSub->eType==p->eType ){
+    int nByte = sizeof(Fts5ExprNode*) * pSub->nChild;
+    memcpy(&p->apChild[p->nChild], pSub->apChild, nByte);
+    p->nChild += pSub->nChild;
+    sqlite3_free(pSub);
+  }else{
+    p->apChild[p->nChild++] = pSub;
+  }
+  for( ; ii<p->nChild; ii++){
+    p->iHeight = MAX(p->iHeight, p->apChild[ii]->iHeight + 1);
+  }
+}
+
+/*
+** This function is used when parsing LIKE or GLOB patterns against
+** trigram indexes that specify either detail=column or detail=none.
+** It converts a phrase:
+**
+**     abc + def + ghi
+**
+** into an AND tree:
+**
+**     abc AND def AND ghi
+*/
+static Fts5ExprNode *fts5ParsePhraseToAnd(
+  Fts5Parse *pParse,
+  Fts5ExprNearset *pNear
+){
+  int nTerm = pNear->apPhrase[0]->nTerm;
+  int ii;
+  int nByte;
+  Fts5ExprNode *pRet;
+
+  assert( pNear->nPhrase==1 );
+  assert( pParse->bPhraseToAnd );
+
+  nByte = sizeof(Fts5ExprNode) + nTerm*sizeof(Fts5ExprNode*);
+  pRet = (Fts5ExprNode*)sqlite3Fts5MallocZero(&pParse->rc, nByte);
+  if( pRet ){
+    pRet->eType = FTS5_AND;
+    pRet->nChild = nTerm;
+    pRet->iHeight = 1;
+    fts5ExprAssignXNext(pRet);
+    pParse->nPhrase--;
+    for(ii=0; ii<nTerm; ii++){
+      Fts5ExprPhrase *pPhrase = (Fts5ExprPhrase*)sqlite3Fts5MallocZero(
+          &pParse->rc, sizeof(Fts5ExprPhrase)
+      );
+      if( pPhrase ){
+        if( parseGrowPhraseArray(pParse) ){
+          fts5ExprPhraseFree(pPhrase);
+        }else{
+          Fts5ExprTerm *p = &pNear->apPhrase[0]->aTerm[ii];
+          Fts5ExprTerm *pTo = &pPhrase->aTerm[0];
+          pParse->apPhrase[pParse->nPhrase++] = pPhrase;
+          pPhrase->nTerm = 1;
+          pTo->pTerm = sqlite3Fts5Strndup(&pParse->rc, p->pTerm, p->nFullTerm);
+          pTo->nQueryTerm = p->nQueryTerm;
+          pTo->nFullTerm = p->nFullTerm;
+          pRet->apChild[ii] = sqlite3Fts5ParseNode(pParse, FTS5_STRING,
+              0, 0, sqlite3Fts5ParseNearset(pParse, 0, pPhrase)
+          );
+        }
+      }
+    }
+
+    if( pParse->rc ){
+      sqlite3Fts5ParseNodeFree(pRet);
+      pRet = 0;
+    }else{
+      sqlite3Fts5ParseNearsetFree(pNear);
+    }
+  }
+
+  return pRet;
+}
+
+/*
+** Allocate and return a new expression object. If anything goes wrong (i.e.
+** OOM error), leave an error code in pParse and return NULL.
+*/
+static Fts5ExprNode *sqlite3Fts5ParseNode(
+  Fts5Parse *pParse,              /* Parse context */
+  int eType,                      /* FTS5_STRING, AND, OR or NOT */
+  Fts5ExprNode *pLeft,            /* Left hand child expression */
+  Fts5ExprNode *pRight,           /* Right hand child expression */
+  Fts5ExprNearset *pNear          /* For STRING expressions, the near cluster */
+){
+  Fts5ExprNode *pRet = 0;
+
+  if( pParse->rc==SQLITE_OK ){
+    int nChild = 0;               /* Number of children of returned node */
+    sqlite3_int64 nByte;          /* Bytes of space to allocate for this node */
+
+    assert( (eType!=FTS5_STRING && !pNear)
+         || (eType==FTS5_STRING && !pLeft && !pRight)
+    );
+    if( eType==FTS5_STRING && pNear==0 ) return 0;
+    if( eType!=FTS5_STRING && pLeft==0 ) return pRight;
+    if( eType!=FTS5_STRING && pRight==0 ) return pLeft;
+
+    if( eType==FTS5_STRING
+     && pParse->bPhraseToAnd
+     && pNear->apPhrase[0]->nTerm>1
+    ){
+      pRet = fts5ParsePhraseToAnd(pParse, pNear);
+    }else{
+      if( eType==FTS5_NOT ){
+        nChild = 2;
+      }else if( eType==FTS5_AND || eType==FTS5_OR ){
+        nChild = 2;
+        if( pLeft->eType==eType ) nChild += pLeft->nChild-1;
+        if( pRight->eType==eType ) nChild += pRight->nChild-1;
+      }
+
+      nByte = sizeof(Fts5ExprNode) + sizeof(Fts5ExprNode*)*(nChild-1);
+      pRet = (Fts5ExprNode*)sqlite3Fts5MallocZero(&pParse->rc, nByte);
+
+      if( pRet ){
+        pRet->eType = eType;
+        pRet->pNear = pNear;
+        fts5ExprAssignXNext(pRet);
+        if( eType==FTS5_STRING ){
+          int iPhrase;
+          for(iPhrase=0; iPhrase<pNear->nPhrase; iPhrase++){
+            pNear->apPhrase[iPhrase]->pNode = pRet;
+            if( pNear->apPhrase[iPhrase]->nTerm==0 ){
+              pRet->xNext = 0;
+              pRet->eType = FTS5_EOF;
+            }
+          }
+
+          if( pParse->pConfig->eDetail!=FTS5_DETAIL_FULL ){
+            Fts5ExprPhrase *pPhrase = pNear->apPhrase[0];
+            if( pNear->nPhrase!=1
+                || pPhrase->nTerm>1
+                || (pPhrase->nTerm>0 && pPhrase->aTerm[0].bFirst)
+              ){
+              sqlite3Fts5ParseError(pParse,
+                  "fts5: %s queries are not supported (detail!=full)",
+                  pNear->nPhrase==1 ? "phrase": "NEAR"
+              );
+              sqlite3Fts5ParseNodeFree(pRet);
+              pRet = 0;
+              pNear = 0;
+              assert( pLeft==0 && pRight==0 );
+            }
+          }
+        }else{
+          assert( pNear==0 );
+          fts5ExprAddChildren(pRet, pLeft);
+          fts5ExprAddChildren(pRet, pRight);
+          pLeft = pRight = 0;
+          if( pRet->iHeight>SQLITE_FTS5_MAX_EXPR_DEPTH ){
+            sqlite3Fts5ParseError(pParse,
+                "fts5 expression tree is too large (maximum depth %d)",
+                SQLITE_FTS5_MAX_EXPR_DEPTH
+            );
+            sqlite3Fts5ParseNodeFree(pRet);
+            pRet = 0;
+          }
+        }
+      }
+    }
+  }
+
+  if( pRet==0 ){
+    assert( pParse->rc!=SQLITE_OK );
+    sqlite3Fts5ParseNodeFree(pLeft);
+    sqlite3Fts5ParseNodeFree(pRight);
+    sqlite3Fts5ParseNearsetFree(pNear);
+  }
+  return pRet;
+}
+
+static Fts5ExprNode *sqlite3Fts5ParseImplicitAnd(
+  Fts5Parse *pParse,              /* Parse context */
+  Fts5ExprNode *pLeft,            /* Left hand child expression */
+  Fts5ExprNode *pRight            /* Right hand child expression */
+){
+  Fts5ExprNode *pRet = 0;
+  Fts5ExprNode *pPrev;
+
+  if( pParse->rc ){
+    sqlite3Fts5ParseNodeFree(pLeft);
+    sqlite3Fts5ParseNodeFree(pRight);
+  }else{
+
+    assert( pLeft->eType==FTS5_STRING
+        || pLeft->eType==FTS5_TERM
+        || pLeft->eType==FTS5_EOF
+        || pLeft->eType==FTS5_AND
+    );
+    assert( pRight->eType==FTS5_STRING
+        || pRight->eType==FTS5_TERM
+        || pRight->eType==FTS5_EOF
+        || (pRight->eType==FTS5_AND && pParse->bPhraseToAnd)
+    );
+
+    if( pLeft->eType==FTS5_AND ){
+      pPrev = pLeft->apChild[pLeft->nChild-1];
+    }else{
+      pPrev = pLeft;
+    }
+    assert( pPrev->eType==FTS5_STRING
+        || pPrev->eType==FTS5_TERM
+        || pPrev->eType==FTS5_EOF
+        );
+
+    if( pRight->eType==FTS5_EOF ){
+      assert( pParse->apPhrase!=0 );
+      assert( pParse->nPhrase>0 );
+      assert( pParse->apPhrase[pParse->nPhrase-1]==pRight->pNear->apPhrase[0] );
+      sqlite3Fts5ParseNodeFree(pRight);
+      pRet = pLeft;
+      pParse->nPhrase--;
+    }
+    else if( pPrev->eType==FTS5_EOF ){
+      Fts5ExprPhrase **ap;
+
+      if( pPrev==pLeft ){
+        pRet = pRight;
+      }else{
+        pLeft->apChild[pLeft->nChild-1] = pRight;
+        pRet = pLeft;
+      }
+
+      ap = &pParse->apPhrase[pParse->nPhrase-1-pRight->pNear->nPhrase];
+      assert( ap[0]==pPrev->pNear->apPhrase[0] );
+      memmove(ap, &ap[1], sizeof(Fts5ExprPhrase*)*pRight->pNear->nPhrase);
+      pParse->nPhrase--;
+
+      sqlite3Fts5ParseNodeFree(pPrev);
+    }
+    else{
+      pRet = sqlite3Fts5ParseNode(pParse, FTS5_AND, pLeft, pRight, 0);
+    }
+  }
+
+  return pRet;
+}
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+static char *fts5ExprTermPrint(Fts5ExprTerm *pTerm){
+  sqlite3_int64 nByte = 0;
+  Fts5ExprTerm *p;
+  char *zQuoted;
+
+  /* Determine the maximum amount of space required. */
+  for(p=pTerm; p; p=p->pSynonym){
+    nByte += pTerm->nQueryTerm * 2 + 3 + 2;
+  }
+  zQuoted = sqlite3_malloc64(nByte);
+
+  if( zQuoted ){
+    int i = 0;
+    for(p=pTerm; p; p=p->pSynonym){
+      char *zIn = p->pTerm;
+      char *zEnd = &zIn[p->nQueryTerm];
+      zQuoted[i++] = '"';
+      while( zIn<zEnd ){
+        if( *zIn=='"' ) zQuoted[i++] = '"';
+        zQuoted[i++] = *zIn++;
+      }
+      zQuoted[i++] = '"';
+      if( p->pSynonym ) zQuoted[i++] = '|';
+    }
+    if( pTerm->bPrefix ){
+      zQuoted[i++] = ' ';
+      zQuoted[i++] = '*';
+    }
+    zQuoted[i++] = '\0';
+  }
+  return zQuoted;
+}
+
+static char *fts5PrintfAppend(char *zApp, const char *zFmt, ...){
+  char *zNew;
+  va_list ap;
+  va_start(ap, zFmt);
+  zNew = sqlite3_vmprintf(zFmt, ap);
+  va_end(ap);
+  if( zApp && zNew ){
+    char *zNew2 = sqlite3_mprintf("%s%s", zApp, zNew);
+    sqlite3_free(zNew);
+    zNew = zNew2;
+  }
+  sqlite3_free(zApp);
+  return zNew;
+}
+
+/*
+** Compose a tcl-readable representation of expression pExpr. Return a
+** pointer to a buffer containing that representation. It is the
+** responsibility of the caller to at some point free the buffer using
+** sqlite3_free().
+*/
+static char *fts5ExprPrintTcl(
+  Fts5Config *pConfig,
+  const char *zNearsetCmd,
+  Fts5ExprNode *pExpr
+){
+  char *zRet = 0;
+  if( pExpr->eType==FTS5_STRING || pExpr->eType==FTS5_TERM ){
+    Fts5ExprNearset *pNear = pExpr->pNear;
+    int i;
+    int iTerm;
+
+    zRet = fts5PrintfAppend(zRet, "%s ", zNearsetCmd);
+    if( zRet==0 ) return 0;
+    if( pNear->pColset ){
+      int *aiCol = pNear->pColset->aiCol;
+      int nCol = pNear->pColset->nCol;
+      if( nCol==1 ){
+        zRet = fts5PrintfAppend(zRet, "-col %d ", aiCol[0]);
+      }else{
+        zRet = fts5PrintfAppend(zRet, "-col {%d", aiCol[0]);
+        for(i=1; i<pNear->pColset->nCol; i++){
+          zRet = fts5PrintfAppend(zRet, " %d", aiCol[i]);
+        }
+        zRet = fts5PrintfAppend(zRet, "} ");
+      }
+      if( zRet==0 ) return 0;
+    }
+
+    if( pNear->nPhrase>1 ){
+      zRet = fts5PrintfAppend(zRet, "-near %d ", pNear->nNear);
+      if( zRet==0 ) return 0;
+    }
+
+    zRet = fts5PrintfAppend(zRet, "--");
+    if( zRet==0 ) return 0;
+
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+
+      zRet = fts5PrintfAppend(zRet, " {");
+      for(iTerm=0; zRet && iTerm<pPhrase->nTerm; iTerm++){
+        Fts5ExprTerm *p = &pPhrase->aTerm[iTerm];
+        zRet = fts5PrintfAppend(zRet, "%s%.*s", iTerm==0?"":" ",
+            p->nQueryTerm, p->pTerm
+        );
+        if( pPhrase->aTerm[iTerm].bPrefix ){
+          zRet = fts5PrintfAppend(zRet, "*");
+        }
+      }
+
+      if( zRet ) zRet = fts5PrintfAppend(zRet, "}");
+      if( zRet==0 ) return 0;
+    }
+
+  }else if( pExpr->eType==0 ){
+    zRet = sqlite3_mprintf("{}");
+  }else{
+    char const *zOp = 0;
+    int i;
+    switch( pExpr->eType ){
+      case FTS5_AND: zOp = "AND"; break;
+      case FTS5_NOT: zOp = "NOT"; break;
+      default:
+        assert( pExpr->eType==FTS5_OR );
+        zOp = "OR";
+        break;
+    }
+
+    zRet = sqlite3_mprintf("%s", zOp);
+    for(i=0; zRet && i<pExpr->nChild; i++){
+      char *z = fts5ExprPrintTcl(pConfig, zNearsetCmd, pExpr->apChild[i]);
+      if( !z ){
+        sqlite3_free(zRet);
+        zRet = 0;
+      }else{
+        zRet = fts5PrintfAppend(zRet, " [%z]", z);
+      }
+    }
+  }
+
+  return zRet;
+}
+
+static char *fts5ExprPrint(Fts5Config *pConfig, Fts5ExprNode *pExpr){
+  char *zRet = 0;
+  if( pExpr->eType==0 ){
+    return sqlite3_mprintf("\"\"");
+  }else
+  if( pExpr->eType==FTS5_STRING || pExpr->eType==FTS5_TERM ){
+    Fts5ExprNearset *pNear = pExpr->pNear;
+    int i;
+    int iTerm;
+
+    if( pNear->pColset ){
+      int ii;
+      Fts5Colset *pColset = pNear->pColset;
+      if( pColset->nCol>1 ) zRet = fts5PrintfAppend(zRet, "{");
+      for(ii=0; ii<pColset->nCol; ii++){
+        zRet = fts5PrintfAppend(zRet, "%s%s",
+            pConfig->azCol[pColset->aiCol[ii]], ii==pColset->nCol-1 ? "" : " "
+        );
+      }
+      if( zRet ){
+        zRet = fts5PrintfAppend(zRet, "%s : ", pColset->nCol>1 ? "}" : "");
+      }
+      if( zRet==0 ) return 0;
+    }
+
+    if( pNear->nPhrase>1 ){
+      zRet = fts5PrintfAppend(zRet, "NEAR(");
+      if( zRet==0 ) return 0;
+    }
+
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      if( i!=0 ){
+        zRet = fts5PrintfAppend(zRet, " ");
+        if( zRet==0 ) return 0;
+      }
+      for(iTerm=0; iTerm<pPhrase->nTerm; iTerm++){
+        char *zTerm = fts5ExprTermPrint(&pPhrase->aTerm[iTerm]);
+        if( zTerm ){
+          zRet = fts5PrintfAppend(zRet, "%s%s", iTerm==0?"":" + ", zTerm);
+          sqlite3_free(zTerm);
+        }
+        if( zTerm==0 || zRet==0 ){
+          sqlite3_free(zRet);
+          return 0;
+        }
+      }
+    }
+
+    if( pNear->nPhrase>1 ){
+      zRet = fts5PrintfAppend(zRet, ", %d)", pNear->nNear);
+      if( zRet==0 ) return 0;
+    }
+
+  }else{
+    char const *zOp = 0;
+    int i;
+
+    switch( pExpr->eType ){
+      case FTS5_AND: zOp = " AND "; break;
+      case FTS5_NOT: zOp = " NOT "; break;
+      default:
+        assert( pExpr->eType==FTS5_OR );
+        zOp = " OR ";
+        break;
+    }
+
+    for(i=0; i<pExpr->nChild; i++){
+      char *z = fts5ExprPrint(pConfig, pExpr->apChild[i]);
+      if( z==0 ){
+        sqlite3_free(zRet);
+        zRet = 0;
+      }else{
+        int e = pExpr->apChild[i]->eType;
+        int b = (e!=FTS5_STRING && e!=FTS5_TERM && e!=FTS5_EOF);
+        zRet = fts5PrintfAppend(zRet, "%s%s%z%s",
+            (i==0 ? "" : zOp),
+            (b?"(":""), z, (b?")":"")
+        );
+      }
+      if( zRet==0 ) break;
+    }
+  }
+
+  return zRet;
+}
+
+/*
+** The implementation of user-defined scalar functions fts5_expr() (bTcl==0)
+** and fts5_expr_tcl() (bTcl!=0).
+*/
+static void fts5ExprFunction(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal,          /* Function arguments */
+  int bTcl
+){
+  Fts5Global *pGlobal = (Fts5Global*)sqlite3_user_data(pCtx);
+  sqlite3 *db = sqlite3_context_db_handle(pCtx);
+  const char *zExpr = 0;
+  char *zErr = 0;
+  Fts5Expr *pExpr = 0;
+  int rc;
+  int i;
+
+  const char **azConfig;          /* Array of arguments for Fts5Config */
+  const char *zNearsetCmd = "nearset";
+  int nConfig;                    /* Size of azConfig[] */
+  Fts5Config *pConfig = 0;
+  int iArg = 1;
+
+  if( nArg<1 ){
+    zErr = sqlite3_mprintf("wrong number of arguments to function %s",
+        bTcl ? "fts5_expr_tcl" : "fts5_expr"
+    );
+    sqlite3_result_error(pCtx, zErr, -1);
+    sqlite3_free(zErr);
+    return;
+  }
+
+  if( bTcl && nArg>1 ){
+    zNearsetCmd = (const char*)sqlite3_value_text(apVal[1]);
+    iArg = 2;
+  }
+
+  nConfig = 3 + (nArg-iArg);
+  azConfig = (const char**)sqlite3_malloc64(sizeof(char*) * nConfig);
+  if( azConfig==0 ){
+    sqlite3_result_error_nomem(pCtx);
+    return;
+  }
+  azConfig[0] = 0;
+  azConfig[1] = "main";
+  azConfig[2] = "tbl";
+  for(i=3; iArg<nArg; iArg++){
+    const char *z = (const char*)sqlite3_value_text(apVal[iArg]);
+    azConfig[i++] = (z ? z : "");
+  }
+
+  zExpr = (const char*)sqlite3_value_text(apVal[0]);
+  if( zExpr==0 ) zExpr = "";
+
+  rc = sqlite3Fts5ConfigParse(pGlobal, db, nConfig, azConfig, &pConfig, &zErr);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ExprNew(pConfig, 0, pConfig->nCol, zExpr, &pExpr, &zErr);
+  }
+  if( rc==SQLITE_OK ){
+    char *zText;
+    if( pExpr->pRoot->xNext==0 ){
+      zText = sqlite3_mprintf("");
+    }else if( bTcl ){
+      zText = fts5ExprPrintTcl(pConfig, zNearsetCmd, pExpr->pRoot);
+    }else{
+      zText = fts5ExprPrint(pConfig, pExpr->pRoot);
+    }
+    if( zText==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      sqlite3_result_text(pCtx, zText, -1, SQLITE_TRANSIENT);
+      sqlite3_free(zText);
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    if( zErr ){
+      sqlite3_result_error(pCtx, zErr, -1);
+      sqlite3_free(zErr);
+    }else{
+      sqlite3_result_error_code(pCtx, rc);
+    }
+  }
+  sqlite3_free((void *)azConfig);
+  sqlite3Fts5ConfigFree(pConfig);
+  sqlite3Fts5ExprFree(pExpr);
+}
+
+static void fts5ExprFunctionHr(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  fts5ExprFunction(pCtx, nArg, apVal, 0);
+}
+static void fts5ExprFunctionTcl(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  fts5ExprFunction(pCtx, nArg, apVal, 1);
+}
+
+/*
+** The implementation of an SQLite user-defined-function that accepts a
+** single integer as an argument. If the integer is an alpha-numeric
+** unicode code point, 1 is returned. Otherwise 0.
+*/
+static void fts5ExprIsAlnum(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  int iCode;
+  u8 aArr[32];
+  if( nArg!=1 ){
+    sqlite3_result_error(pCtx,
+        "wrong number of arguments to function fts5_isalnum", -1
+    );
+    return;
+  }
+  memset(aArr, 0, sizeof(aArr));
+  sqlite3Fts5UnicodeCatParse("L*", aArr);
+  sqlite3Fts5UnicodeCatParse("N*", aArr);
+  sqlite3Fts5UnicodeCatParse("Co", aArr);
+  iCode = sqlite3_value_int(apVal[0]);
+  sqlite3_result_int(pCtx, aArr[sqlite3Fts5UnicodeCategory((u32)iCode)]);
+}
+
+static void fts5ExprFold(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  if( nArg!=1 && nArg!=2 ){
+    sqlite3_result_error(pCtx,
+        "wrong number of arguments to function fts5_fold", -1
+    );
+  }else{
+    int iCode;
+    int bRemoveDiacritics = 0;
+    iCode = sqlite3_value_int(apVal[0]);
+    if( nArg==2 ) bRemoveDiacritics = sqlite3_value_int(apVal[1]);
+    sqlite3_result_int(pCtx, sqlite3Fts5UnicodeFold(iCode, bRemoveDiacritics));
+  }
+}
+#endif /* if SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+/*
+** This is called during initialization to register the fts5_expr() scalar
+** UDF with the SQLite handle passed as the only argument.
+*/
+static int sqlite3Fts5ExprInit(Fts5Global *pGlobal, sqlite3 *db){
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+  struct Fts5ExprFunc {
+    const char *z;
+    void (*x)(sqlite3_context*,int,sqlite3_value**);
+  } aFunc[] = {
+    { "fts5_expr",     fts5ExprFunctionHr },
+    { "fts5_expr_tcl", fts5ExprFunctionTcl },
+    { "fts5_isalnum",  fts5ExprIsAlnum },
+    { "fts5_fold",     fts5ExprFold },
+  };
+  int i;
+  int rc = SQLITE_OK;
+  void *pCtx = (void*)pGlobal;
+
+  for(i=0; rc==SQLITE_OK && i<ArraySize(aFunc); i++){
+    struct Fts5ExprFunc *p = &aFunc[i];
+    rc = sqlite3_create_function(db, p->z, -1, SQLITE_UTF8, pCtx, p->x, 0, 0);
+  }
+#else
+  int rc = SQLITE_OK;
+  UNUSED_PARAM2(pGlobal,db);
+#endif
+
+  /* Avoid warnings indicating that sqlite3Fts5ParserTrace() and
+  ** sqlite3Fts5ParserFallback() are unused */
+#ifndef NDEBUG
+  (void)sqlite3Fts5ParserTrace;
+#endif
+  (void)sqlite3Fts5ParserFallback;
+
+  return rc;
+}
+
+/*
+** Return the number of phrases in expression pExpr.
+*/
+static int sqlite3Fts5ExprPhraseCount(Fts5Expr *pExpr){
+  return (pExpr ? pExpr->nPhrase : 0);
+}
+
+/*
+** Return the number of terms in the iPhrase'th phrase in pExpr.
+*/
+static int sqlite3Fts5ExprPhraseSize(Fts5Expr *pExpr, int iPhrase){
+  if( iPhrase<0 || iPhrase>=pExpr->nPhrase ) return 0;
+  return pExpr->apExprPhrase[iPhrase]->nTerm;
+}
+
+/*
+** This function is used to access the current position list for phrase
+** iPhrase.
+*/
+static int sqlite3Fts5ExprPoslist(Fts5Expr *pExpr, int iPhrase, const u8 **pa){
+  int nRet;
+  Fts5ExprPhrase *pPhrase = pExpr->apExprPhrase[iPhrase];
+  Fts5ExprNode *pNode = pPhrase->pNode;
+  if( pNode->bEof==0 && pNode->iRowid==pExpr->pRoot->iRowid ){
+    *pa = pPhrase->poslist.p;
+    nRet = pPhrase->poslist.n;
+  }else{
+    *pa = 0;
+    nRet = 0;
+  }
+  return nRet;
+}
+
+struct Fts5PoslistPopulator {
+  Fts5PoslistWriter writer;
+  int bOk;                        /* True if ok to populate */
+  int bMiss;
+};
+
+/*
+** Clear the position lists associated with all phrases in the expression
+** passed as the first argument. Argument bLive is true if the expression
+** might be pointing to a real entry, otherwise it has just been reset.
+**
+** At present this function is only used for detail=col and detail=none
+** fts5 tables. This implies that all phrases must be at most 1 token
+** in size, as phrase matches are not supported without detail=full.
+*/
+static Fts5PoslistPopulator *sqlite3Fts5ExprClearPoslists(Fts5Expr *pExpr, int bLive){
+  Fts5PoslistPopulator *pRet;
+  pRet = sqlite3_malloc64(sizeof(Fts5PoslistPopulator)*pExpr->nPhrase);
+  if( pRet ){
+    int i;
+    memset(pRet, 0, sizeof(Fts5PoslistPopulator)*pExpr->nPhrase);
+    for(i=0; i<pExpr->nPhrase; i++){
+      Fts5Buffer *pBuf = &pExpr->apExprPhrase[i]->poslist;
+      Fts5ExprNode *pNode = pExpr->apExprPhrase[i]->pNode;
+      assert( pExpr->apExprPhrase[i]->nTerm<=1 );
+      if( bLive &&
+          (pBuf->n==0 || pNode->iRowid!=pExpr->pRoot->iRowid || pNode->bEof)
+      ){
+        pRet[i].bMiss = 1;
+      }else{
+        pBuf->n = 0;
+      }
+    }
+  }
+  return pRet;
+}
+
+struct Fts5ExprCtx {
+  Fts5Expr *pExpr;
+  Fts5PoslistPopulator *aPopulator;
+  i64 iOff;
+};
+typedef struct Fts5ExprCtx Fts5ExprCtx;
+
+/*
+** TODO: Make this more efficient!
+*/
+static int fts5ExprColsetTest(Fts5Colset *pColset, int iCol){
+  int i;
+  for(i=0; i<pColset->nCol; i++){
+    if( pColset->aiCol[i]==iCol ) return 1;
+  }
+  return 0;
+}
+
+/*
+** pToken is a buffer nToken bytes in size that may or may not contain
+** an embedded 0x00 byte. If it does, return the number of bytes in
+** the buffer before the 0x00. If it does not, return nToken.
+*/
+static int fts5QueryTerm(const char *pToken, int nToken){
+  int ii;
+  for(ii=0; ii<nToken && pToken[ii]; ii++){}
+  return ii;
+}
+
+static int fts5ExprPopulatePoslistsCb(
+  void *pCtx,                /* Copy of 2nd argument to xTokenize() */
+  int tflags,                /* Mask of FTS5_TOKEN_* flags */
+  const char *pToken,        /* Pointer to buffer containing token */
+  int nToken,                /* Size of token in bytes */
+  int iUnused1,              /* Byte offset of token within input text */
+  int iUnused2               /* Byte offset of end of token within input text */
+){
+  Fts5ExprCtx *p = (Fts5ExprCtx*)pCtx;
+  Fts5Expr *pExpr = p->pExpr;
+  int i;
+  int nQuery = nToken;
+  i64 iRowid = pExpr->pRoot->iRowid;
+
+  UNUSED_PARAM2(iUnused1, iUnused2);
+
+  if( nQuery>FTS5_MAX_TOKEN_SIZE ) nQuery = FTS5_MAX_TOKEN_SIZE;
+  if( pExpr->pConfig->bTokendata ){
+    nQuery = fts5QueryTerm(pToken, nQuery);
+  }
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 ) p->iOff++;
+  for(i=0; i<pExpr->nPhrase; i++){
+    Fts5ExprTerm *pT;
+    if( p->aPopulator[i].bOk==0 ) continue;
+    for(pT=&pExpr->apExprPhrase[i]->aTerm[0]; pT; pT=pT->pSynonym){
+      if( (pT->nQueryTerm==nQuery || (pT->nQueryTerm<nQuery && pT->bPrefix))
+       && memcmp(pT->pTerm, pToken, pT->nQueryTerm)==0
+      ){
+        int rc = sqlite3Fts5PoslistWriterAppend(
+            &pExpr->apExprPhrase[i]->poslist, &p->aPopulator[i].writer, p->iOff
+        );
+        if( rc==SQLITE_OK && (pExpr->pConfig->bTokendata || pT->bPrefix) ){
+          int iCol = p->iOff>>32;
+          int iTokOff = p->iOff & 0x7FFFFFFF;
+          rc = sqlite3Fts5IndexIterWriteTokendata(
+              pT->pIter, pToken, nToken, iRowid, iCol, iTokOff
+          );
+        }
+        if( rc ) return rc;
+        break;
+      }
+    }
+  }
+  return SQLITE_OK;
+}
+
+static int sqlite3Fts5ExprPopulatePoslists(
+  Fts5Config *pConfig,
+  Fts5Expr *pExpr,
+  Fts5PoslistPopulator *aPopulator,
+  int iCol,
+  const char *z, int n
+){
+  int i;
+  Fts5ExprCtx sCtx;
+  sCtx.pExpr = pExpr;
+  sCtx.aPopulator = aPopulator;
+  sCtx.iOff = (((i64)iCol) << 32) - 1;
+
+  for(i=0; i<pExpr->nPhrase; i++){
+    Fts5ExprNode *pNode = pExpr->apExprPhrase[i]->pNode;
+    Fts5Colset *pColset = pNode->pNear->pColset;
+    if( (pColset && 0==fts5ExprColsetTest(pColset, iCol))
+     || aPopulator[i].bMiss
+    ){
+      aPopulator[i].bOk = 0;
+    }else{
+      aPopulator[i].bOk = 1;
+    }
+  }
+
+  return sqlite3Fts5Tokenize(pConfig,
+      FTS5_TOKENIZE_DOCUMENT, z, n, (void*)&sCtx, fts5ExprPopulatePoslistsCb
+  );
+}
+
+static void fts5ExprClearPoslists(Fts5ExprNode *pNode){
+  if( pNode->eType==FTS5_TERM || pNode->eType==FTS5_STRING ){
+    pNode->pNear->apPhrase[0]->poslist.n = 0;
+  }else{
+    int i;
+    for(i=0; i<pNode->nChild; i++){
+      fts5ExprClearPoslists(pNode->apChild[i]);
+    }
+  }
+}
+
+static int fts5ExprCheckPoslists(Fts5ExprNode *pNode, i64 iRowid){
+  pNode->iRowid = iRowid;
+  pNode->bEof = 0;
+  switch( pNode->eType ){
+    case 0:
+    case FTS5_TERM:
+    case FTS5_STRING:
+      return (pNode->pNear->apPhrase[0]->poslist.n>0);
+
+    case FTS5_AND: {
+      int i;
+      for(i=0; i<pNode->nChild; i++){
+        if( fts5ExprCheckPoslists(pNode->apChild[i], iRowid)==0 ){
+          fts5ExprClearPoslists(pNode);
+          return 0;
+        }
+      }
+      break;
+    }
+
+    case FTS5_OR: {
+      int i;
+      int bRet = 0;
+      for(i=0; i<pNode->nChild; i++){
+        if( fts5ExprCheckPoslists(pNode->apChild[i], iRowid) ){
+          bRet = 1;
+        }
+      }
+      return bRet;
+    }
+
+    default: {
+      assert( pNode->eType==FTS5_NOT );
+      if( 0==fts5ExprCheckPoslists(pNode->apChild[0], iRowid)
+          || 0!=fts5ExprCheckPoslists(pNode->apChild[1], iRowid)
+        ){
+        fts5ExprClearPoslists(pNode);
+        return 0;
+      }
+      break;
+    }
+  }
+  return 1;
+}
+
+static void sqlite3Fts5ExprCheckPoslists(Fts5Expr *pExpr, i64 iRowid){
+  fts5ExprCheckPoslists(pExpr->pRoot, iRowid);
+}
+
+/*
+** This function is only called for detail=columns tables.
+*/
+static int sqlite3Fts5ExprPhraseCollist(
+  Fts5Expr *pExpr,
+  int iPhrase,
+  const u8 **ppCollist,
+  int *pnCollist
+){
+  Fts5ExprPhrase *pPhrase = pExpr->apExprPhrase[iPhrase];
+  Fts5ExprNode *pNode = pPhrase->pNode;
+  int rc = SQLITE_OK;
+
+  assert( iPhrase>=0 && iPhrase<pExpr->nPhrase );
+  assert( pExpr->pConfig->eDetail==FTS5_DETAIL_COLUMNS );
+
+  if( pNode->bEof==0
+   && pNode->iRowid==pExpr->pRoot->iRowid
+   && pPhrase->poslist.n>0
+  ){
+    Fts5ExprTerm *pTerm = &pPhrase->aTerm[0];
+    if( pTerm->pSynonym ){
+      Fts5Buffer *pBuf = (Fts5Buffer*)&pTerm->pSynonym[1];
+      rc = fts5ExprSynonymList(
+          pTerm, pNode->iRowid, pBuf, (u8**)ppCollist, pnCollist
+      );
+    }else{
+      *ppCollist = pPhrase->aTerm[0].pIter->pData;
+      *pnCollist = pPhrase->aTerm[0].pIter->nData;
+    }
+  }else{
+    *ppCollist = 0;
+    *pnCollist = 0;
+  }
+
+  return rc;
+}
+
+/*
+** Does the work of the fts5_api.xQueryToken() API method.
+*/
+static int sqlite3Fts5ExprQueryToken(
+  Fts5Expr *pExpr,
+  int iPhrase,
+  int iToken,
+  const char **ppOut,
+  int *pnOut
+){
+  Fts5ExprPhrase *pPhrase = 0;
+
+  if( iPhrase<0 || iPhrase>=pExpr->nPhrase ){
+    return SQLITE_RANGE;
+  }
+  pPhrase = pExpr->apExprPhrase[iPhrase];
+  if( iToken<0 || iToken>=pPhrase->nTerm ){
+    return SQLITE_RANGE;
+  }
+
+  *ppOut = pPhrase->aTerm[iToken].pTerm;
+  *pnOut = pPhrase->aTerm[iToken].nFullTerm;
+  return SQLITE_OK;
+}
+
+/*
+** Does the work of the fts5_api.xInstToken() API method.
+*/
+static int sqlite3Fts5ExprInstToken(
+  Fts5Expr *pExpr,
+  i64 iRowid,
+  int iPhrase,
+  int iCol,
+  int iOff,
+  int iToken,
+  const char **ppOut,
+  int *pnOut
+){
+  Fts5ExprPhrase *pPhrase = 0;
+  Fts5ExprTerm *pTerm = 0;
+  int rc = SQLITE_OK;
+
+  if( iPhrase<0 || iPhrase>=pExpr->nPhrase ){
+    return SQLITE_RANGE;
+  }
+  pPhrase = pExpr->apExprPhrase[iPhrase];
+  if( iToken<0 || iToken>=pPhrase->nTerm ){
+    return SQLITE_RANGE;
+  }
+  pTerm = &pPhrase->aTerm[iToken];
+  if( pExpr->pConfig->bTokendata || pTerm->bPrefix ){
+    rc = sqlite3Fts5IterToken(
+        pTerm->pIter, pTerm->pTerm, pTerm->nQueryTerm,
+        iRowid, iCol, iOff+iToken, ppOut, pnOut
+    );
+  }else{
+    *ppOut = pTerm->pTerm;
+    *pnOut = pTerm->nFullTerm;
+  }
+  return rc;
+}
+
+/*
+** Clear the token mappings for all Fts5IndexIter objects mannaged by
+** the expression passed as the only argument.
+*/
+static void sqlite3Fts5ExprClearTokens(Fts5Expr *pExpr){
+  int ii;
+  for(ii=0; ii<pExpr->nPhrase; ii++){
+    Fts5ExprTerm *pT;
+    for(pT=&pExpr->apExprPhrase[ii]->aTerm[0]; pT; pT=pT->pSynonym){
+      sqlite3Fts5IndexIterClearTokendata(pT->pIter);
+    }
+  }
+}
+
+/*
+** 2014 August 11
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+
+
+
+/* #include "fts5Int.h" */
+
+typedef struct Fts5HashEntry Fts5HashEntry;
+
+/*
+** This file contains the implementation of an in-memory hash table used
+** to accumuluate "term -> doclist" content before it is flused to a level-0
+** segment.
+*/
+
+
+struct Fts5Hash {
+  int eDetail;                    /* Copy of Fts5Config.eDetail */
+  int *pnByte;                    /* Pointer to bytes counter */
+  int nEntry;                     /* Number of entries currently in hash */
+  int nSlot;                      /* Size of aSlot[] array */
+  Fts5HashEntry *pScan;           /* Current ordered scan item */
+  Fts5HashEntry **aSlot;          /* Array of hash slots */
+};
+
+/*
+** Each entry in the hash table is represented by an object of the
+** following type. Each object, its key, and its current data are stored
+** in a single memory allocation. The key immediately follows the object
+** in memory. The position list data immediately follows the key data
+** in memory.
+**
+** The key is Fts5HashEntry.nKey bytes in size. It consists of a single
+** byte identifying the index (either the main term index or a prefix-index),
+** followed by the term data. For example: "0token". There is no
+** nul-terminator - in this case nKey=6.
+**
+** The data that follows the key is in a similar, but not identical format
+** to the doclist data stored in the database. It is:
+**
+**   * Rowid, as a varint
+**   * Position list, without 0x00 terminator.
+**   * Size of previous position list and rowid, as a 4 byte
+**     big-endian integer.
+**
+** iRowidOff:
+**   Offset of last rowid written to data area. Relative to first byte of
+**   structure.
+**
+** nData:
+**   Bytes of data written since iRowidOff.
+*/
+struct Fts5HashEntry {
+  Fts5HashEntry *pHashNext;       /* Next hash entry with same hash-key */
+  Fts5HashEntry *pScanNext;       /* Next entry in sorted order */
+
+  int nAlloc;                     /* Total size of allocation */
+  int iSzPoslist;                 /* Offset of space for 4-byte poslist size */
+  int nData;                      /* Total bytes of data (incl. structure) */
+  int nKey;                       /* Length of key in bytes */
+  u8 bDel;                        /* Set delete-flag @ iSzPoslist */
+  u8 bContent;                    /* Set content-flag (detail=none mode) */
+  i16 iCol;                       /* Column of last value written */
+  int iPos;                       /* Position of last value written */
+  i64 iRowid;                     /* Rowid of last value written */
+};
+
+/*
+** Eqivalent to:
+**
+**   char *fts5EntryKey(Fts5HashEntry *pEntry){ return zKey; }
+*/
+#define fts5EntryKey(p) ( ((char *)(&(p)[1])) )
+
+
+/*
+** Allocate a new hash table.
+*/
+static int sqlite3Fts5HashNew(Fts5Config *pConfig, Fts5Hash **ppNew, int *pnByte){
+  int rc = SQLITE_OK;
+  Fts5Hash *pNew;
+
+  *ppNew = pNew = (Fts5Hash*)sqlite3_malloc(sizeof(Fts5Hash));
+  if( pNew==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_int64 nByte;
+    memset(pNew, 0, sizeof(Fts5Hash));
+    pNew->pnByte = pnByte;
+    pNew->eDetail = pConfig->eDetail;
+
+    pNew->nSlot = 1024;
+    nByte = sizeof(Fts5HashEntry*) * pNew->nSlot;
+    pNew->aSlot = (Fts5HashEntry**)sqlite3_malloc64(nByte);
+    if( pNew->aSlot==0 ){
+      sqlite3_free(pNew);
+      *ppNew = 0;
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pNew->aSlot, 0, (size_t)nByte);
+    }
+  }
+  return rc;
+}
+
+/*
+** Free a hash table object.
+*/
+static void sqlite3Fts5HashFree(Fts5Hash *pHash){
+  if( pHash ){
+    sqlite3Fts5HashClear(pHash);
+    sqlite3_free(pHash->aSlot);
+    sqlite3_free(pHash);
+  }
+}
+
+/*
+** Empty (but do not delete) a hash table.
+*/
+static void sqlite3Fts5HashClear(Fts5Hash *pHash){
+  int i;
+  for(i=0; i<pHash->nSlot; i++){
+    Fts5HashEntry *pNext;
+    Fts5HashEntry *pSlot;
+    for(pSlot=pHash->aSlot[i]; pSlot; pSlot=pNext){
+      pNext = pSlot->pHashNext;
+      sqlite3_free(pSlot);
+    }
+  }
+  memset(pHash->aSlot, 0, pHash->nSlot * sizeof(Fts5HashEntry*));
+  pHash->nEntry = 0;
+}
+
+static unsigned int fts5HashKey(int nSlot, const u8 *p, int n){
+  int i;
+  unsigned int h = 13;
+  for(i=n-1; i>=0; i--){
+    h = (h << 3) ^ h ^ p[i];
+  }
+  return (h % nSlot);
+}
+
+static unsigned int fts5HashKey2(int nSlot, u8 b, const u8 *p, int n){
+  int i;
+  unsigned int h = 13;
+  for(i=n-1; i>=0; i--){
+    h = (h << 3) ^ h ^ p[i];
+  }
+  h = (h << 3) ^ h ^ b;
+  return (h % nSlot);
+}
+
+/*
+** Resize the hash table by doubling the number of slots.
+*/
+static int fts5HashResize(Fts5Hash *pHash){
+  int nNew = pHash->nSlot*2;
+  int i;
+  Fts5HashEntry **apNew;
+  Fts5HashEntry **apOld = pHash->aSlot;
+
+  apNew = (Fts5HashEntry**)sqlite3_malloc64(nNew*sizeof(Fts5HashEntry*));
+  if( !apNew ) return SQLITE_NOMEM;
+  memset(apNew, 0, nNew*sizeof(Fts5HashEntry*));
+
+  for(i=0; i<pHash->nSlot; i++){
+    while( apOld[i] ){
+      unsigned int iHash;
+      Fts5HashEntry *p = apOld[i];
+      apOld[i] = p->pHashNext;
+      iHash = fts5HashKey(nNew, (u8*)fts5EntryKey(p), p->nKey);
+      p->pHashNext = apNew[iHash];
+      apNew[iHash] = p;
+    }
+  }
+
+  sqlite3_free(apOld);
+  pHash->nSlot = nNew;
+  pHash->aSlot = apNew;
+  return SQLITE_OK;
+}
+
+static int fts5HashAddPoslistSize(
+  Fts5Hash *pHash,
+  Fts5HashEntry *p,
+  Fts5HashEntry *p2
+){
+  int nRet = 0;
+  if( p->iSzPoslist ){
+    u8 *pPtr = p2 ? (u8*)p2 : (u8*)p;
+    int nData = p->nData;
+    if( pHash->eDetail==FTS5_DETAIL_NONE ){
+      assert( nData==p->iSzPoslist );
+      if( p->bDel ){
+        pPtr[nData++] = 0x00;
+        if( p->bContent ){
+          pPtr[nData++] = 0x00;
+        }
+      }
+    }else{
+      int nSz = (nData - p->iSzPoslist - 1);       /* Size in bytes */
+      int nPos = nSz*2 + p->bDel;                     /* Value of nPos field */
+
+      assert( p->bDel==0 || p->bDel==1 );
+      if( nPos<=127 ){
+        pPtr[p->iSzPoslist] = (u8)nPos;
+      }else{
+        int nByte = sqlite3Fts5GetVarintLen((u32)nPos);
+        memmove(&pPtr[p->iSzPoslist + nByte], &pPtr[p->iSzPoslist + 1], nSz);
+        sqlite3Fts5PutVarint(&pPtr[p->iSzPoslist], nPos);
+        nData += (nByte-1);
+      }
+    }
+
+    nRet = nData - p->nData;
+    if( p2==0 ){
+      p->iSzPoslist = 0;
+      p->bDel = 0;
+      p->bContent = 0;
+      p->nData = nData;
+    }
+  }
+  return nRet;
+}
+
+/*
+** Add an entry to the in-memory hash table. The key is the concatenation
+** of bByte and (pToken/nToken). The value is (iRowid/iCol/iPos).
+**
+**     (bByte || pToken) -> (iRowid,iCol,iPos)
+**
+** Or, if iCol is negative, then the value is a delete marker.
+*/
+static int sqlite3Fts5HashWrite(
+  Fts5Hash *pHash,
+  i64 iRowid,                     /* Rowid for this entry */
+  int iCol,                       /* Column token appears in (-ve -> delete) */
+  int iPos,                       /* Position of token within column */
+  char bByte,                     /* First byte of token */
+  const char *pToken, int nToken  /* Token to add or remove to or from index */
+){
+  unsigned int iHash;
+  Fts5HashEntry *p;
+  u8 *pPtr;
+  int nIncr = 0;                  /* Amount to increment (*pHash->pnByte) by */
+  int bNew;                       /* If non-delete entry should be written */
+
+  bNew = (pHash->eDetail==FTS5_DETAIL_FULL);
+
+  /* Attempt to locate an existing hash entry */
+  iHash = fts5HashKey2(pHash->nSlot, (u8)bByte, (const u8*)pToken, nToken);
+  for(p=pHash->aSlot[iHash]; p; p=p->pHashNext){
+    char *zKey = fts5EntryKey(p);
+    if( zKey[0]==bByte
+     && p->nKey==nToken+1
+     && memcmp(&zKey[1], pToken, nToken)==0
+    ){
+      break;
+    }
+  }
+
+  /* If an existing hash entry cannot be found, create a new one. */
+  if( p==0 ){
+    /* Figure out how much space to allocate */
+    char *zKey;
+    sqlite3_int64 nByte = sizeof(Fts5HashEntry) + (nToken+1) + 1 + 64;
+    if( nByte<128 ) nByte = 128;
+
+    /* Grow the Fts5Hash.aSlot[] array if necessary. */
+    if( (pHash->nEntry*2)>=pHash->nSlot ){
+      int rc = fts5HashResize(pHash);
+      if( rc!=SQLITE_OK ) return rc;
+      iHash = fts5HashKey2(pHash->nSlot, (u8)bByte, (const u8*)pToken, nToken);
+    }
+
+    /* Allocate new Fts5HashEntry and add it to the hash table. */
+    p = (Fts5HashEntry*)sqlite3_malloc64(nByte);
+    if( !p ) return SQLITE_NOMEM;
+    memset(p, 0, sizeof(Fts5HashEntry));
+    p->nAlloc = (int)nByte;
+    zKey = fts5EntryKey(p);
+    zKey[0] = bByte;
+    memcpy(&zKey[1], pToken, nToken);
+    assert( iHash==fts5HashKey(pHash->nSlot, (u8*)zKey, nToken+1) );
+    p->nKey = nToken+1;
+    zKey[nToken+1] = '\0';
+    p->nData = nToken+1 + sizeof(Fts5HashEntry);
+    p->pHashNext = pHash->aSlot[iHash];
+    pHash->aSlot[iHash] = p;
+    pHash->nEntry++;
+
+    /* Add the first rowid field to the hash-entry */
+    p->nData += sqlite3Fts5PutVarint(&((u8*)p)[p->nData], iRowid);
+    p->iRowid = iRowid;
+
+    p->iSzPoslist = p->nData;
+    if( pHash->eDetail!=FTS5_DETAIL_NONE ){
+      p->nData += 1;
+      p->iCol = (pHash->eDetail==FTS5_DETAIL_FULL ? 0 : -1);
+    }
+
+  }else{
+
+    /* Appending to an existing hash-entry. Check that there is enough
+    ** space to append the largest possible new entry. Worst case scenario
+    ** is:
+    **
+    **     + 9 bytes for a new rowid,
+    **     + 4 byte reserved for the "poslist size" varint.
+    **     + 1 byte for a "new column" byte,
+    **     + 3 bytes for a new column number (16-bit max) as a varint,
+    **     + 5 bytes for the new position offset (32-bit max).
+    */
+    if( (p->nAlloc - p->nData) < (9 + 4 + 1 + 3 + 5) ){
+      sqlite3_int64 nNew = p->nAlloc * 2;
+      Fts5HashEntry *pNew;
+      Fts5HashEntry **pp;
+      pNew = (Fts5HashEntry*)sqlite3_realloc64(p, nNew);
+      if( pNew==0 ) return SQLITE_NOMEM;
+      pNew->nAlloc = (int)nNew;
+      for(pp=&pHash->aSlot[iHash]; *pp!=p; pp=&(*pp)->pHashNext);
+      *pp = pNew;
+      p = pNew;
+    }
+    nIncr -= p->nData;
+  }
+  assert( (p->nAlloc - p->nData) >= (9 + 4 + 1 + 3 + 5) );
+
+  pPtr = (u8*)p;
+
+  /* If this is a new rowid, append the 4-byte size field for the previous
+  ** entry, and the new rowid for this entry.  */
+  if( iRowid!=p->iRowid ){
+    u64 iDiff = (u64)iRowid - (u64)p->iRowid;
+    fts5HashAddPoslistSize(pHash, p, 0);
+    p->nData += sqlite3Fts5PutVarint(&pPtr[p->nData], iDiff);
+    p->iRowid = iRowid;
+    bNew = 1;
+    p->iSzPoslist = p->nData;
+    if( pHash->eDetail!=FTS5_DETAIL_NONE ){
+      p->nData += 1;
+      p->iCol = (pHash->eDetail==FTS5_DETAIL_FULL ? 0 : -1);
+      p->iPos = 0;
+    }
+  }
+
+  if( iCol>=0 ){
+    if( pHash->eDetail==FTS5_DETAIL_NONE ){
+      p->bContent = 1;
+    }else{
+      /* Append a new column value, if necessary */
+      assert_nc( iCol>=p->iCol );
+      if( iCol!=p->iCol ){
+        if( pHash->eDetail==FTS5_DETAIL_FULL ){
+          pPtr[p->nData++] = 0x01;
+          p->nData += sqlite3Fts5PutVarint(&pPtr[p->nData], iCol);
+          p->iCol = (i16)iCol;
+          p->iPos = 0;
+        }else{
+          bNew = 1;
+          p->iCol = (i16)(iPos = iCol);
+        }
+      }
+
+      /* Append the new position offset, if necessary */
+      if( bNew ){
+        p->nData += sqlite3Fts5PutVarint(&pPtr[p->nData], iPos - p->iPos + 2);
+        p->iPos = iPos;
+      }
+    }
+  }else{
+    /* This is a delete. Set the delete flag. */
+    p->bDel = 1;
+  }
+
+  nIncr += p->nData;
+  *pHash->pnByte += nIncr;
+  return SQLITE_OK;
+}
+
+
+/*
+** Arguments pLeft and pRight point to linked-lists of hash-entry objects,
+** each sorted in key order. This function merges the two lists into a
+** single list and returns a pointer to its first element.
+*/
+static Fts5HashEntry *fts5HashEntryMerge(
+  Fts5HashEntry *pLeft,
+  Fts5HashEntry *pRight
+){
+  Fts5HashEntry *p1 = pLeft;
+  Fts5HashEntry *p2 = pRight;
+  Fts5HashEntry *pRet = 0;
+  Fts5HashEntry **ppOut = &pRet;
+
+  while( p1 || p2 ){
+    if( p1==0 ){
+      *ppOut = p2;
+      p2 = 0;
+    }else if( p2==0 ){
+      *ppOut = p1;
+      p1 = 0;
+    }else{
+      char *zKey1 = fts5EntryKey(p1);
+      char *zKey2 = fts5EntryKey(p2);
+      int nMin = MIN(p1->nKey, p2->nKey);
+
+      int cmp = memcmp(zKey1, zKey2, nMin);
+      if( cmp==0 ){
+        cmp = p1->nKey - p2->nKey;
+      }
+      assert( cmp!=0 );
+
+      if( cmp>0 ){
+        /* p2 is smaller */
+        *ppOut = p2;
+        ppOut = &p2->pScanNext;
+        p2 = p2->pScanNext;
+      }else{
+        /* p1 is smaller */
+        *ppOut = p1;
+        ppOut = &p1->pScanNext;
+        p1 = p1->pScanNext;
+      }
+      *ppOut = 0;
+    }
+  }
+
+  return pRet;
+}
+
+/*
+** Link all tokens from hash table iHash into a list in sorted order. The
+** tokens are not removed from the hash table.
+*/
+static int fts5HashEntrySort(
+  Fts5Hash *pHash,
+  const char *pTerm, int nTerm,   /* Query prefix, if any */
+  Fts5HashEntry **ppSorted
+){
+  const int nMergeSlot = 32;
+  Fts5HashEntry **ap;
+  Fts5HashEntry *pList;
+  int iSlot;
+  int i;
+
+  *ppSorted = 0;
+  ap = sqlite3_malloc64(sizeof(Fts5HashEntry*) * nMergeSlot);
+  if( !ap ) return SQLITE_NOMEM;
+  memset(ap, 0, sizeof(Fts5HashEntry*) * nMergeSlot);
+
+  for(iSlot=0; iSlot<pHash->nSlot; iSlot++){
+    Fts5HashEntry *pIter;
+    for(pIter=pHash->aSlot[iSlot]; pIter; pIter=pIter->pHashNext){
+      if( pTerm==0
+       || (pIter->nKey>=nTerm && 0==memcmp(fts5EntryKey(pIter), pTerm, nTerm))
+      ){
+        Fts5HashEntry *pEntry = pIter;
+        pEntry->pScanNext = 0;
+        for(i=0; ap[i]; i++){
+          pEntry = fts5HashEntryMerge(pEntry, ap[i]);
+          ap[i] = 0;
+        }
+        ap[i] = pEntry;
+      }
+    }
+  }
+
+  pList = 0;
+  for(i=0; i<nMergeSlot; i++){
+    pList = fts5HashEntryMerge(pList, ap[i]);
+  }
+
+  sqlite3_free(ap);
+  *ppSorted = pList;
+  return SQLITE_OK;
+}
+
+/*
+** Query the hash table for a doclist associated with term pTerm/nTerm.
+*/
+static int sqlite3Fts5HashQuery(
+  Fts5Hash *pHash,                /* Hash table to query */
+  int nPre,
+  const char *pTerm, int nTerm,   /* Query term */
+  void **ppOut,                   /* OUT: Pointer to new object */
+  int *pnDoclist                  /* OUT: Size of doclist in bytes */
+){
+  unsigned int iHash = fts5HashKey(pHash->nSlot, (const u8*)pTerm, nTerm);
+  char *zKey = 0;
+  Fts5HashEntry *p;
+
+  for(p=pHash->aSlot[iHash]; p; p=p->pHashNext){
+    zKey = fts5EntryKey(p);
+    if( nTerm==p->nKey && memcmp(zKey, pTerm, nTerm)==0 ) break;
+  }
+
+  if( p ){
+    int nHashPre = sizeof(Fts5HashEntry) + nTerm;
+    int nList = p->nData - nHashPre;
+    u8 *pRet = (u8*)(*ppOut = sqlite3_malloc64(nPre + nList + 10));
+    if( pRet ){
+      Fts5HashEntry *pFaux = (Fts5HashEntry*)&pRet[nPre-nHashPre];
+      memcpy(&pRet[nPre], &((u8*)p)[nHashPre], nList);
+      nList += fts5HashAddPoslistSize(pHash, p, pFaux);
+      *pnDoclist = nList;
+    }else{
+      *pnDoclist = 0;
+      return SQLITE_NOMEM;
+    }
+  }else{
+    *ppOut = 0;
+    *pnDoclist = 0;
+  }
+
+  return SQLITE_OK;
+}
+
+static int sqlite3Fts5HashScanInit(
+  Fts5Hash *p,                    /* Hash table to query */
+  const char *pTerm, int nTerm    /* Query prefix */
+){
+  return fts5HashEntrySort(p, pTerm, nTerm, &p->pScan);
+}
+
+#ifdef SQLITE_DEBUG
+static int fts5HashCount(Fts5Hash *pHash){
+  int nEntry = 0;
+  int ii;
+  for(ii=0; ii<pHash->nSlot; ii++){
+    Fts5HashEntry *p = 0;
+    for(p=pHash->aSlot[ii]; p; p=p->pHashNext){
+      nEntry++;
+    }
+  }
+  return nEntry;
+}
+#endif
+
+/*
+** Return true if the hash table is empty, false otherwise.
+*/
+static int sqlite3Fts5HashIsEmpty(Fts5Hash *pHash){
+  assert( pHash->nEntry==fts5HashCount(pHash) );
+  return pHash->nEntry==0;
+}
+
+static void sqlite3Fts5HashScanNext(Fts5Hash *p){
+  assert( !sqlite3Fts5HashScanEof(p) );
+  p->pScan = p->pScan->pScanNext;
+}
+
+static int sqlite3Fts5HashScanEof(Fts5Hash *p){
+  return (p->pScan==0);
+}
+
+static void sqlite3Fts5HashScanEntry(
+  Fts5Hash *pHash,
+  const char **pzTerm,            /* OUT: term (nul-terminated) */
+  int *pnTerm,                    /* OUT: Size of term in bytes */
+  const u8 **ppDoclist,           /* OUT: pointer to doclist */
+  int *pnDoclist                  /* OUT: size of doclist in bytes */
+){
+  Fts5HashEntry *p;
+  if( (p = pHash->pScan) ){
+    char *zKey = fts5EntryKey(p);
+    int nTerm = p->nKey;
+    fts5HashAddPoslistSize(pHash, p, 0);
+    *pzTerm = zKey;
+    *pnTerm = nTerm;
+    *ppDoclist = (const u8*)&zKey[nTerm];
+    *pnDoclist = p->nData - (sizeof(Fts5HashEntry) + nTerm);
+  }else{
+    *pzTerm = 0;
+    *pnTerm = 0;
+    *ppDoclist = 0;
+    *pnDoclist = 0;
+  }
+}
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Low level access to the FTS index stored in the database file. The
+** routines in this file file implement all read and write access to the
+** %_data table. Other parts of the system access this functionality via
+** the interface defined in fts5Int.h.
+*/
+
+
+/* #include "fts5Int.h" */
+
+/*
+** Overview:
+**
+** The %_data table contains all the FTS indexes for an FTS5 virtual table.
+** As well as the main term index, there may be up to 31 prefix indexes.
+** The format is similar to FTS3/4, except that:
+**
+**   * all segment b-tree leaf data is stored in fixed size page records
+**     (e.g. 1000 bytes). A single doclist may span multiple pages. Care is
+**     taken to ensure it is possible to iterate in either direction through
+**     the entries in a doclist, or to seek to a specific entry within a
+**     doclist, without loading it into memory.
+**
+**   * large doclists that span many pages have associated "doclist index"
+**     records that contain a copy of the first rowid on each page spanned by
+**     the doclist. This is used to speed up seek operations, and merges of
+**     large doclists with very small doclists.
+**
+**   * extra fields in the "structure record" record the state of ongoing
+**     incremental merge operations.
+**
+*/
+
+
+#define FTS5_OPT_WORK_UNIT  1000  /* Number of leaf pages per optimize step */
+#define FTS5_WORK_UNIT      64    /* Number of leaf pages in unit of work */
+
+#define FTS5_MIN_DLIDX_SIZE 4     /* Add dlidx if this many empty pages */
+
+#define FTS5_MAIN_PREFIX '0'
+
+#if FTS5_MAX_PREFIX_INDEXES > 31
+# error "FTS5_MAX_PREFIX_INDEXES is too large"
+#endif
+
+#define FTS5_MAX_LEVEL 64
+
+/*
+** There are two versions of the format used for the structure record:
+**
+**   1. the legacy format, that may be read by all fts5 versions, and
+**
+**   2. the V2 format, which is used by contentless_delete=1 databases.
+**
+** Both begin with a 4-byte "configuration cookie" value. Then, a legacy
+** format structure record contains a varint - the number of levels in
+** the structure. Whereas a V2 structure record contains the constant
+** 4 bytes [0xff 0x00 0x00 0x01]. This is unambiguous as the value of a
+** varint has to be at least 16256 to begin with "0xFF". And the default
+** maximum number of levels is 64.
+**
+** See below for more on structure record formats.
+*/
+#define FTS5_STRUCTURE_V2 "\xFF\x00\x00\x01"
+
+/*
+** Details:
+**
+** The %_data table managed by this module,
+**
+**     CREATE TABLE %_data(id INTEGER PRIMARY KEY, block BLOB);
+**
+** , contains the following 6 types of records. See the comments surrounding
+** the FTS5_*_ROWID macros below for a description of how %_data rowids are
+** assigned to each fo them.
+**
+** 1. Structure Records:
+**
+**   The set of segments that make up an index - the index structure - are
+**   recorded in a single record within the %_data table. The record consists
+**   of a single 32-bit configuration cookie value followed by a list of
+**   SQLite varints.
+**
+**   If the structure record is a V2 record, the configuration cookie is
+**   followed by the following 4 bytes: [0xFF 0x00 0x00 0x01].
+**
+**   Next, the record continues with three varints:
+**
+**     + number of levels,
+**     + total number of segments on all levels,
+**     + value of write counter.
+**
+**   Then, for each level from 0 to nMax:
+**
+**     + number of input segments in ongoing merge.
+**     + total number of segments in level.
+**     + for each segment from oldest to newest:
+**         + segment id (always > 0)
+**         + first leaf page number (often 1, always greater than 0)
+**         + final leaf page number
+**
+**      Then, for V2 structures only:
+**
+**         + lower origin counter value,
+**         + upper origin counter value,
+**         + the number of tombstone hash pages.
+**
+** 2. The Averages Record:
+**
+**   A single record within the %_data table. The data is a list of varints.
+**   The first value is the number of rows in the index. Then, for each column
+**   from left to right, the total number of tokens in the column for all
+**   rows of the table.
+**
+** 3. Segment leaves:
+**
+**   TERM/DOCLIST FORMAT:
+**
+**     Most of each segment leaf is taken up by term/doclist data. The
+**     general format of term/doclist, starting with the first term
+**     on the leaf page, is:
+**
+**         varint : size of first term
+**         blob:    first term data
+**         doclist: first doclist
+**         zero-or-more {
+**           varint:  number of bytes in common with previous term
+**           varint:  number of bytes of new term data (nNew)
+**           blob:    nNew bytes of new term data
+**           doclist: next doclist
+**         }
+**
+**     doclist format:
+**
+**         varint:  first rowid
+**         poslist: first poslist
+**         zero-or-more {
+**           varint:  rowid delta (always > 0)
+**           poslist: next poslist
+**         }
+**
+**     poslist format:
+**
+**         varint: size of poslist in bytes multiplied by 2, not including
+**                 this field. Plus 1 if this entry carries the "delete" flag.
+**         collist: collist for column 0
+**         zero-or-more {
+**           0x01 byte
+**           varint: column number (I)
+**           collist: collist for column I
+**         }
+**
+**     collist format:
+**
+**         varint: first offset + 2
+**         zero-or-more {
+**           varint: offset delta + 2
+**         }
+**
+**   PAGE FORMAT
+**
+**     Each leaf page begins with a 4-byte header containing 2 16-bit
+**     unsigned integer fields in big-endian format. They are:
+**
+**       * The byte offset of the first rowid on the page, if it exists
+**         and occurs before the first term (otherwise 0).
+**
+**       * The byte offset of the start of the page footer. If the page
+**         footer is 0 bytes in size, then this field is the same as the
+**         size of the leaf page in bytes.
+**
+**     The page footer consists of a single varint for each term located
+**     on the page. Each varint is the byte offset of the current term
+**     within the page, delta-compressed against the previous value. In
+**     other words, the first varint in the footer is the byte offset of
+**     the first term, the second is the byte offset of the second less that
+**     of the first, and so on.
+**
+**     The term/doclist format described above is accurate if the entire
+**     term/doclist data fits on a single leaf page. If this is not the case,
+**     the format is changed in two ways:
+**
+**       + if the first rowid on a page occurs before the first term, it
+**         is stored as a literal value:
+**
+**             varint:  first rowid
+**
+**       + the first term on each page is stored in the same way as the
+**         very first term of the segment:
+**
+**             varint : size of first term
+**             blob:    first term data
+**
+** 5. Segment doclist indexes:
+**
+**   Doclist indexes are themselves b-trees, however they usually consist of
+**   a single leaf record only. The format of each doclist index leaf page
+**   is:
+**
+**     * Flags byte. Bits are:
+**         0x01: Clear if leaf is also the root page, otherwise set.
+**
+**     * Page number of fts index leaf page. As a varint.
+**
+**     * First rowid on page indicated by previous field. As a varint.
+**
+**     * A list of varints, one for each subsequent termless page. A
+**       positive delta if the termless page contains at least one rowid,
+**       or an 0x00 byte otherwise.
+**
+**   Internal doclist index nodes are:
+**
+**     * Flags byte. Bits are:
+**         0x01: Clear for root page, otherwise set.
+**
+**     * Page number of first child page. As a varint.
+**
+**     * Copy of first rowid on page indicated by previous field. As a varint.
+**
+**     * A list of delta-encoded varints - the first rowid on each subsequent
+**       child page.
+**
+** 6. Tombstone Hash Page
+**
+**   These records are only ever present in contentless_delete=1 tables.
+**   There are zero or more of these associated with each segment. They
+**   are used to store the tombstone rowids for rows contained in the
+**   associated segments.
+**
+**   The set of nHashPg tombstone hash pages associated with a single
+**   segment together form a single hash table containing tombstone rowids.
+**   To find the page of the hash on which a key might be stored:
+**
+**       iPg = (rowid % nHashPg)
+**
+**   Then, within page iPg, which has nSlot slots:
+**
+**       iSlot = (rowid / nHashPg) % nSlot
+**
+**   Each tombstone hash page begins with an 8 byte header:
+**
+**     1-byte:  Key-size (the size in bytes of each slot). Either 4 or 8.
+**     1-byte:  rowid-0-tombstone flag. This flag is only valid on the
+**              first tombstone hash page for each segment (iPg=0). If set,
+**              the hash table contains rowid 0. If clear, it does not.
+**              Rowid 0 is handled specially.
+**     2-bytes: unused.
+**     4-bytes: Big-endian integer containing number of entries on page.
+**
+**   Following this are nSlot 4 or 8 byte slots (depending on the key-size
+**   in the first byte of the page header). The number of slots may be
+**   determined based on the size of the page record and the key-size:
+**
+**     nSlot = (nByte - 8) / key-size
+*/
+
+/*
+** Rowids for the averages and structure records in the %_data table.
+*/
+#define FTS5_AVERAGES_ROWID     1    /* Rowid used for the averages record */
+#define FTS5_STRUCTURE_ROWID   10    /* The structure record */
+
+/*
+** Macros determining the rowids used by segment leaves and dlidx leaves
+** and nodes. All nodes and leaves are stored in the %_data table with large
+** positive rowids.
+**
+** Each segment has a unique non-zero 16-bit id.
+**
+** The rowid for each segment leaf is found by passing the segment id and
+** the leaf page number to the FTS5_SEGMENT_ROWID macro. Leaves are numbered
+** sequentially starting from 1.
+*/
+#define FTS5_DATA_ID_B     16     /* Max seg id number 65535 */
+#define FTS5_DATA_DLI_B     1     /* Doclist-index flag (1 bit) */
+#define FTS5_DATA_HEIGHT_B  5     /* Max dlidx tree height of 32 */
+#define FTS5_DATA_PAGE_B   31     /* Max page number of 2147483648 */
+
+#define fts5_dri(segid, dlidx, height, pgno) (                                 \
+ ((i64)(segid)  << (FTS5_DATA_PAGE_B+FTS5_DATA_HEIGHT_B+FTS5_DATA_DLI_B)) +    \
+ ((i64)(dlidx)  << (FTS5_DATA_PAGE_B + FTS5_DATA_HEIGHT_B)) +                  \
+ ((i64)(height) << (FTS5_DATA_PAGE_B)) +                                       \
+ ((i64)(pgno))                                                                 \
+)
+
+#define FTS5_SEGMENT_ROWID(segid, pgno)       fts5_dri(segid, 0, 0, pgno)
+#define FTS5_DLIDX_ROWID(segid, height, pgno) fts5_dri(segid, 1, height, pgno)
+#define FTS5_TOMBSTONE_ROWID(segid,ipg)       fts5_dri(segid+(1<<16), 0, 0, ipg)
+
+#ifdef SQLITE_DEBUG
+static int sqlite3Fts5Corrupt() { return SQLITE_CORRUPT_VTAB; }
+#endif
+
+
+/*
+** Each time a blob is read from the %_data table, it is padded with this
+** many zero bytes. This makes it easier to decode the various record formats
+** without overreading if the records are corrupt.
+*/
+#define FTS5_DATA_ZERO_PADDING 8
+#define FTS5_DATA_PADDING 20
+
+typedef struct Fts5Data Fts5Data;
+typedef struct Fts5DlidxIter Fts5DlidxIter;
+typedef struct Fts5DlidxLvl Fts5DlidxLvl;
+typedef struct Fts5DlidxWriter Fts5DlidxWriter;
+typedef struct Fts5Iter Fts5Iter;
+typedef struct Fts5PageWriter Fts5PageWriter;
+typedef struct Fts5SegIter Fts5SegIter;
+typedef struct Fts5DoclistIter Fts5DoclistIter;
+typedef struct Fts5SegWriter Fts5SegWriter;
+typedef struct Fts5Structure Fts5Structure;
+typedef struct Fts5StructureLevel Fts5StructureLevel;
+typedef struct Fts5StructureSegment Fts5StructureSegment;
+typedef struct Fts5TokenDataIter Fts5TokenDataIter;
+typedef struct Fts5TokenDataMap Fts5TokenDataMap;
+typedef struct Fts5TombstoneArray Fts5TombstoneArray;
+
+struct Fts5Data {
+  u8 *p;                          /* Pointer to buffer containing record */
+  int nn;                         /* Size of record in bytes */
+  int szLeaf;                     /* Size of leaf without page-index */
+};
+
+/*
+** One object per %_data table.
+**
+** nContentlessDelete:
+**   The number of contentless delete operations since the most recent
+**   call to fts5IndexFlush() or fts5IndexDiscardData(). This is tracked
+**   so that extra auto-merge work can be done by fts5IndexFlush() to
+**   account for the delete operations.
+*/
+struct Fts5Index {
+  Fts5Config *pConfig;            /* Virtual table configuration */
+  char *zDataTbl;                 /* Name of %_data table */
+  int nWorkUnit;                  /* Leaf pages in a "unit" of work */
+
+  /*
+  ** Variables related to the accumulation of tokens and doclists within the
+  ** in-memory hash tables before they are flushed to disk.
+  */
+  Fts5Hash *pHash;                /* Hash table for in-memory data */
+  int nPendingData;               /* Current bytes of pending data */
+  i64 iWriteRowid;                /* Rowid for current doc being written */
+  int bDelete;                    /* Current write is a delete */
+  int nContentlessDelete;         /* Number of contentless delete ops */
+  int nPendingRow;                /* Number of INSERT in hash table */
+
+  /* Error state. */
+  int rc;                         /* Current error code */
+  int flushRc;
+
+  /* State used by the fts5DataXXX() functions. */
+  sqlite3_blob *pReader;          /* RO incr-blob open on %_data table */
+  sqlite3_stmt *pWriter;          /* "INSERT ... %_data VALUES(?,?)" */
+  sqlite3_stmt *pDeleter;         /* "DELETE FROM %_data ... id>=? AND id<=?" */
+  sqlite3_stmt *pIdxWriter;       /* "INSERT ... %_idx VALUES(?,?,?,?)" */
+  sqlite3_stmt *pIdxDeleter;      /* "DELETE FROM %_idx WHERE segid=?" */
+  sqlite3_stmt *pIdxSelect;
+  sqlite3_stmt *pIdxNextSelect;
+  int nRead;                      /* Total number of blocks read */
+
+  sqlite3_stmt *pDeleteFromIdx;
+
+  sqlite3_stmt *pDataVersion;
+  i64 iStructVersion;             /* data_version when pStruct read */
+  Fts5Structure *pStruct;         /* Current db structure (or NULL) */
+};
+
+struct Fts5DoclistIter {
+  u8 *aEof;                       /* Pointer to 1 byte past end of doclist */
+
+  /* Output variables. aPoslist==0 at EOF */
+  i64 iRowid;
+  u8 *aPoslist;
+  int nPoslist;
+  int nSize;
+};
+
+/*
+** The contents of the "structure" record for each index are represented
+** using an Fts5Structure record in memory. Which uses instances of the
+** other Fts5StructureXXX types as components.
+**
+** nOriginCntr:
+**   This value is set to non-zero for structure records created for
+**   contentlessdelete=1 tables only. In that case it represents the
+**   origin value to apply to the next top-level segment created.
+*/
+struct Fts5StructureSegment {
+  int iSegid;                     /* Segment id */
+  int pgnoFirst;                  /* First leaf page number in segment */
+  int pgnoLast;                   /* Last leaf page number in segment */
+
+  /* contentlessdelete=1 tables only: */
+  u64 iOrigin1;
+  u64 iOrigin2;
+  int nPgTombstone;               /* Number of tombstone hash table pages */
+  u64 nEntryTombstone;            /* Number of tombstone entries that "count" */
+  u64 nEntry;                     /* Number of rows in this segment */
+};
+struct Fts5StructureLevel {
+  int nMerge;                     /* Number of segments in incr-merge */
+  int nSeg;                       /* Total number of segments on level */
+  Fts5StructureSegment *aSeg;     /* Array of segments. aSeg[0] is oldest. */
+};
+struct Fts5Structure {
+  int nRef;                       /* Object reference count */
+  u64 nWriteCounter;              /* Total leaves written to level 0 */
+  u64 nOriginCntr;                /* Origin value for next top-level segment */
+  int nSegment;                   /* Total segments in this structure */
+  int nLevel;                     /* Number of levels in this index */
+  Fts5StructureLevel aLevel[1];   /* Array of nLevel level objects */
+};
+
+/*
+** An object of type Fts5SegWriter is used to write to segments.
+*/
+struct Fts5PageWriter {
+  int pgno;                       /* Page number for this page */
+  int iPrevPgidx;                 /* Previous value written into pgidx */
+  Fts5Buffer buf;                 /* Buffer containing leaf data */
+  Fts5Buffer pgidx;               /* Buffer containing page-index */
+  Fts5Buffer term;                /* Buffer containing previous term on page */
+};
+struct Fts5DlidxWriter {
+  int pgno;                       /* Page number for this page */
+  int bPrevValid;                 /* True if iPrev is valid */
+  i64 iPrev;                      /* Previous rowid value written to page */
+  Fts5Buffer buf;                 /* Buffer containing page data */
+};
+struct Fts5SegWriter {
+  int iSegid;                     /* Segid to write to */
+  Fts5PageWriter writer;          /* PageWriter object */
+  i64 iPrevRowid;                 /* Previous rowid written to current leaf */
+  u8 bFirstRowidInDoclist;        /* True if next rowid is first in doclist */
+  u8 bFirstRowidInPage;           /* True if next rowid is first in page */
+  /* TODO1: Can use (writer.pgidx.n==0) instead of bFirstTermInPage */
+  u8 bFirstTermInPage;            /* True if next term will be first in leaf */
+  int nLeafWritten;               /* Number of leaf pages written */
+  int nEmpty;                     /* Number of contiguous term-less nodes */
+
+  int nDlidx;                     /* Allocated size of aDlidx[] array */
+  Fts5DlidxWriter *aDlidx;        /* Array of Fts5DlidxWriter objects */
+
+  /* Values to insert into the %_idx table */
+  Fts5Buffer btterm;              /* Next term to insert into %_idx table */
+  int iBtPage;                    /* Page number corresponding to btterm */
+};
+
+typedef struct Fts5CResult Fts5CResult;
+struct Fts5CResult {
+  u16 iFirst;                     /* aSeg[] index of firstest iterator */
+  u8 bTermEq;                     /* True if the terms are equal */
+};
+
+/*
+** Object for iterating through a single segment, visiting each term/rowid
+** pair in the segment.
+**
+** pSeg:
+**   The segment to iterate through.
+**
+** iLeafPgno:
+**   Current leaf page number within segment.
+**
+** iLeafOffset:
+**   Byte offset within the current leaf that is the first byte of the
+**   position list data (one byte passed the position-list size field).
+**
+** pLeaf:
+**   Buffer containing current leaf page data. Set to NULL at EOF.
+**
+** iTermLeafPgno, iTermLeafOffset:
+**   Leaf page number containing the last term read from the segment. And
+**   the offset immediately following the term data.
+**
+** flags:
+**   Mask of FTS5_SEGITER_XXX values. Interpreted as follows:
+**
+**   FTS5_SEGITER_ONETERM:
+**     If set, set the iterator to point to EOF after the current doclist
+**     has been exhausted. Do not proceed to the next term in the segment.
+**
+**   FTS5_SEGITER_REVERSE:
+**     This flag is only ever set if FTS5_SEGITER_ONETERM is also set. If
+**     it is set, iterate through rowid in descending order instead of the
+**     default ascending order.
+**
+** iRowidOffset/nRowidOffset/aRowidOffset:
+**     These are used if the FTS5_SEGITER_REVERSE flag is set.
+**
+**     For each rowid on the page corresponding to the current term, the
+**     corresponding aRowidOffset[] entry is set to the byte offset of the
+**     start of the "position-list-size" field within the page.
+**
+** iTermIdx:
+**     Index of current term on iTermLeafPgno.
+**
+** apTombstone/nTombstone:
+**     These are used for contentless_delete=1 tables only. When the cursor
+**     is first allocated, the apTombstone[] array is allocated so that it
+**     is large enough for all tombstones hash pages associated with the
+**     segment. The pages themselves are loaded lazily from the database as
+**     they are required.
+*/
+struct Fts5SegIter {
+  Fts5StructureSegment *pSeg;     /* Segment to iterate through */
+  int flags;                      /* Mask of configuration flags */
+  int iLeafPgno;                  /* Current leaf page number */
+  Fts5Data *pLeaf;                /* Current leaf data */
+  Fts5Data *pNextLeaf;            /* Leaf page (iLeafPgno+1) */
+  i64 iLeafOffset;                /* Byte offset within current leaf */
+  Fts5TombstoneArray *pTombArray; /* Array of tombstone pages */
+
+  /* Next method */
+  void (*xNext)(Fts5Index*, Fts5SegIter*, int*);
+
+  /* The page and offset from which the current term was read. The offset
+  ** is the offset of the first rowid in the current doclist.  */
+  int iTermLeafPgno;
+  int iTermLeafOffset;
+
+  int iPgidxOff;                  /* Next offset in pgidx */
+  int iEndofDoclist;
+
+  /* The following are only used if the FTS5_SEGITER_REVERSE flag is set. */
+  int iRowidOffset;               /* Current entry in aRowidOffset[] */
+  int nRowidOffset;               /* Allocated size of aRowidOffset[] array */
+  int *aRowidOffset;              /* Array of offset to rowid fields */
+
+  Fts5DlidxIter *pDlidx;          /* If there is a doclist-index */
+
+  /* Variables populated based on current entry. */
+  Fts5Buffer term;                /* Current term */
+  i64 iRowid;                     /* Current rowid */
+  int nPos;                       /* Number of bytes in current position list */
+  u8 bDel;                        /* True if the delete flag is set */
+};
+
+/*
+** Array of tombstone pages. Reference counted.
+*/
+struct Fts5TombstoneArray {
+  int nRef;                       /* Number of pointers to this object */
+  int nTombstone;
+  Fts5Data *apTombstone[1];       /* Array of tombstone pages */
+};
+
+/*
+** Argument is a pointer to an Fts5Data structure that contains a
+** leaf page.
+*/
+#define ASSERT_SZLEAF_OK(x) assert( \
+    (x)->szLeaf==(x)->nn || (x)->szLeaf==fts5GetU16(&(x)->p[2]) \
+)
+
+#define FTS5_SEGITER_ONETERM 0x01
+#define FTS5_SEGITER_REVERSE 0x02
+
+/*
+** Argument is a pointer to an Fts5Data structure that contains a leaf
+** page. This macro evaluates to true if the leaf contains no terms, or
+** false if it contains at least one term.
+*/
+#define fts5LeafIsTermless(x) ((x)->szLeaf >= (x)->nn)
+
+#define fts5LeafTermOff(x, i) (fts5GetU16(&(x)->p[(x)->szLeaf + (i)*2]))
+
+#define fts5LeafFirstRowidOff(x) (fts5GetU16((x)->p))
+
+/*
+** Object for iterating through the merged results of one or more segments,
+** visiting each term/rowid pair in the merged data.
+**
+** nSeg is always a power of two greater than or equal to the number of
+** segments that this object is merging data from. Both the aSeg[] and
+** aFirst[] arrays are sized at nSeg entries. The aSeg[] array is padded
+** with zeroed objects - these are handled as if they were iterators opened
+** on empty segments.
+**
+** The results of comparing segments aSeg[N] and aSeg[N+1], where N is an
+** even number, is stored in aFirst[(nSeg+N)/2]. The "result" of the
+** comparison in this context is the index of the iterator that currently
+** points to the smaller term/rowid combination. Iterators at EOF are
+** considered to be greater than all other iterators.
+**
+** aFirst[1] contains the index in aSeg[] of the iterator that points to
+** the smallest key overall. aFirst[0] is unused.
+**
+** poslist:
+**   Used by sqlite3Fts5IterPoslist() when the poslist needs to be buffered.
+**   There is no way to tell if this is populated or not.
+**
+** pColset:
+**   If not NULL, points to an object containing a set of column indices.
+**   Only matches that occur in one of these columns will be returned.
+**   The Fts5Iter does not own the Fts5Colset object, and so it is not
+**   freed when the iterator is closed - it is owned by the upper layer.
+*/
+struct Fts5Iter {
+  Fts5IndexIter base;             /* Base class containing output vars */
+  Fts5TokenDataIter *pTokenDataIter;
+
+  Fts5Index *pIndex;              /* Index that owns this iterator */
+  Fts5Buffer poslist;             /* Buffer containing current poslist */
+  Fts5Colset *pColset;            /* Restrict matches to these columns */
+
+  /* Invoked to set output variables. */
+  void (*xSetOutputs)(Fts5Iter*, Fts5SegIter*);
+
+  int nSeg;                       /* Size of aSeg[] array */
+  int bRev;                       /* True to iterate in reverse order */
+  u8 bSkipEmpty;                  /* True to skip deleted entries */
+
+  i64 iSwitchRowid;               /* Firstest rowid of other than aFirst[1] */
+  Fts5CResult *aFirst;            /* Current merge state (see above) */
+  Fts5SegIter aSeg[1];            /* Array of segment iterators */
+};
+
+/*
+** An instance of the following type is used to iterate through the contents
+** of a doclist-index record.
+**
+** pData:
+**   Record containing the doclist-index data.
+**
+** bEof:
+**   Set to true once iterator has reached EOF.
+**
+** iOff:
+**   Set to the current offset within record pData.
+*/
+struct Fts5DlidxLvl {
+  Fts5Data *pData;              /* Data for current page of this level */
+  int iOff;                     /* Current offset into pData */
+  int bEof;                     /* At EOF already */
+  int iFirstOff;                /* Used by reverse iterators */
+
+  /* Output variables */
+  int iLeafPgno;                /* Page number of current leaf page */
+  i64 iRowid;                   /* First rowid on leaf iLeafPgno */
+};
+struct Fts5DlidxIter {
+  int nLvl;
+  int iSegid;
+  Fts5DlidxLvl aLvl[1];
+};
+
+static void fts5PutU16(u8 *aOut, u16 iVal){
+  aOut[0] = (iVal>>8);
+  aOut[1] = (iVal&0xFF);
+}
+
+static u16 fts5GetU16(const u8 *aIn){
+  return ((u16)aIn[0] << 8) + aIn[1];
+}
+
+/*
+** The only argument points to a buffer at least 8 bytes in size. This
+** function interprets the first 8 bytes of the buffer as a 64-bit big-endian
+** unsigned integer and returns the result.
+*/
+static u64 fts5GetU64(u8 *a){
+  return ((u64)a[0] << 56)
+       + ((u64)a[1] << 48)
+       + ((u64)a[2] << 40)
+       + ((u64)a[3] << 32)
+       + ((u64)a[4] << 24)
+       + ((u64)a[5] << 16)
+       + ((u64)a[6] << 8)
+       + ((u64)a[7] << 0);
+}
+
+/*
+** The only argument points to a buffer at least 4 bytes in size. This
+** function interprets the first 4 bytes of the buffer as a 32-bit big-endian
+** unsigned integer and returns the result.
+*/
+static u32 fts5GetU32(const u8 *a){
+  return ((u32)a[0] << 24)
+       + ((u32)a[1] << 16)
+       + ((u32)a[2] << 8)
+       + ((u32)a[3] << 0);
+}
+
+/*
+** Write iVal, formated as a 64-bit big-endian unsigned integer, to the
+** buffer indicated by the first argument.
+*/
+static void fts5PutU64(u8 *a, u64 iVal){
+  a[0] = ((iVal >> 56) & 0xFF);
+  a[1] = ((iVal >> 48) & 0xFF);
+  a[2] = ((iVal >> 40) & 0xFF);
+  a[3] = ((iVal >> 32) & 0xFF);
+  a[4] = ((iVal >> 24) & 0xFF);
+  a[5] = ((iVal >> 16) & 0xFF);
+  a[6] = ((iVal >>  8) & 0xFF);
+  a[7] = ((iVal >>  0) & 0xFF);
+}
+
+/*
+** Write iVal, formated as a 32-bit big-endian unsigned integer, to the
+** buffer indicated by the first argument.
+*/
+static void fts5PutU32(u8 *a, u32 iVal){
+  a[0] = ((iVal >> 24) & 0xFF);
+  a[1] = ((iVal >> 16) & 0xFF);
+  a[2] = ((iVal >>  8) & 0xFF);
+  a[3] = ((iVal >>  0) & 0xFF);
+}
+
+/*
+** Allocate and return a buffer at least nByte bytes in size.
+**
+** If an OOM error is encountered, return NULL and set the error code in
+** the Fts5Index handle passed as the first argument.
+*/
+static void *fts5IdxMalloc(Fts5Index *p, sqlite3_int64 nByte){
+  return sqlite3Fts5MallocZero(&p->rc, nByte);
+}
+
+/*
+** Compare the contents of the pLeft buffer with the pRight/nRight blob.
+**
+** Return -ve if pLeft is smaller than pRight, 0 if they are equal or
+** +ve if pRight is smaller than pLeft. In other words:
+**
+**     res = *pLeft - *pRight
+*/
+#ifdef SQLITE_DEBUG
+static int fts5BufferCompareBlob(
+  Fts5Buffer *pLeft,              /* Left hand side of comparison */
+  const u8 *pRight, int nRight    /* Right hand side of comparison */
+){
+  int nCmp = MIN(pLeft->n, nRight);
+  int res = memcmp(pLeft->p, pRight, nCmp);
+  return (res==0 ? (pLeft->n - nRight) : res);
+}
+#endif
+
+/*
+** Compare the contents of the two buffers using memcmp(). If one buffer
+** is a prefix of the other, it is considered the lesser.
+**
+** Return -ve if pLeft is smaller than pRight, 0 if they are equal or
+** +ve if pRight is smaller than pLeft. In other words:
+**
+**     res = *pLeft - *pRight
+*/
+static int fts5BufferCompare(Fts5Buffer *pLeft, Fts5Buffer *pRight){
+  int nCmp, res;
+  nCmp = MIN(pLeft->n, pRight->n);
+  assert( nCmp<=0 || pLeft->p!=0 );
+  assert( nCmp<=0 || pRight->p!=0 );
+  res = fts5Memcmp(pLeft->p, pRight->p, nCmp);
+  return (res==0 ? (pLeft->n - pRight->n) : res);
+}
+
+static int fts5LeafFirstTermOff(Fts5Data *pLeaf){
+  int ret;
+  fts5GetVarint32(&pLeaf->p[pLeaf->szLeaf], ret);
+  return ret;
+}
+
+/*
+** Close the read-only blob handle, if it is open.
+*/
+static void fts5IndexCloseReader(Fts5Index *p){
+  if( p->pReader ){
+    int rc;
+    sqlite3_blob *pReader = p->pReader;
+    p->pReader = 0;
+    rc = sqlite3_blob_close(pReader);
+    if( p->rc==SQLITE_OK ) p->rc = rc;
+  }
+}
+
+/*
+** Retrieve a record from the %_data table.
+**
+** If an error occurs, NULL is returned and an error left in the
+** Fts5Index object.
+*/
+static Fts5Data *fts5DataRead(Fts5Index *p, i64 iRowid){
+  Fts5Data *pRet = 0;
+  if( p->rc==SQLITE_OK ){
+    int rc = SQLITE_OK;
+
+    if( p->pReader ){
+      /* This call may return SQLITE_ABORT if there has been a savepoint
+      ** rollback since it was last used. In this case a new blob handle
+      ** is required.  */
+      sqlite3_blob *pBlob = p->pReader;
+      p->pReader = 0;
+      rc = sqlite3_blob_reopen(pBlob, iRowid);
+      assert( p->pReader==0 );
+      p->pReader = pBlob;
+      if( rc!=SQLITE_OK ){
+        fts5IndexCloseReader(p);
+      }
+      if( rc==SQLITE_ABORT ) rc = SQLITE_OK;
+    }
+
+    /* If the blob handle is not open at this point, open it and seek
+    ** to the requested entry.  */
+    if( p->pReader==0 && rc==SQLITE_OK ){
+      Fts5Config *pConfig = p->pConfig;
+      rc = sqlite3_blob_open(pConfig->db,
+          pConfig->zDb, p->zDataTbl, "block", iRowid, 0, &p->pReader
+      );
+    }
+
+    /* If either of the sqlite3_blob_open() or sqlite3_blob_reopen() calls
+    ** above returned SQLITE_ERROR, return SQLITE_CORRUPT_VTAB instead.
+    ** All the reasons those functions might return SQLITE_ERROR - missing
+    ** table, missing row, non-blob/text in block column - indicate
+    ** backing store corruption.  */
+    if( rc==SQLITE_ERROR ) rc = FTS5_CORRUPT;
+
+    if( rc==SQLITE_OK ){
+      u8 *aOut = 0;               /* Read blob data into this buffer */
+      int nByte = sqlite3_blob_bytes(p->pReader);
+      int szData = (sizeof(Fts5Data) + 7) & ~7;
+      sqlite3_int64 nAlloc = szData + nByte + FTS5_DATA_PADDING;
+      pRet = (Fts5Data*)sqlite3_malloc64(nAlloc);
+      if( pRet ){
+        pRet->nn = nByte;
+        aOut = pRet->p = (u8*)pRet + szData;
+      }else{
+        rc = SQLITE_NOMEM;
+      }
+
+      if( rc==SQLITE_OK ){
+        rc = sqlite3_blob_read(p->pReader, aOut, nByte, 0);
+      }
+      if( rc!=SQLITE_OK ){
+        sqlite3_free(pRet);
+        pRet = 0;
+      }else{
+        /* TODO1: Fix this */
+        pRet->p[nByte] = 0x00;
+        pRet->p[nByte+1] = 0x00;
+        pRet->szLeaf = fts5GetU16(&pRet->p[2]);
+      }
+    }
+    p->rc = rc;
+    p->nRead++;
+  }
+
+  assert( (pRet==0)==(p->rc!=SQLITE_OK) );
+  assert( pRet==0 || EIGHT_BYTE_ALIGNMENT( pRet->p ) );
+  return pRet;
+}
+
+
+/*
+** Release a reference to data record returned by an earlier call to
+** fts5DataRead().
+*/
+static void fts5DataRelease(Fts5Data *pData){
+  sqlite3_free(pData);
+}
+
+static Fts5Data *fts5LeafRead(Fts5Index *p, i64 iRowid){
+  Fts5Data *pRet = fts5DataRead(p, iRowid);
+  if( pRet ){
+    if( pRet->nn<4 || pRet->szLeaf>pRet->nn ){
+      p->rc = FTS5_CORRUPT;
+      fts5DataRelease(pRet);
+      pRet = 0;
+    }
+  }
+  return pRet;
+}
+
+static int fts5IndexPrepareStmt(
+  Fts5Index *p,
+  sqlite3_stmt **ppStmt,
+  char *zSql
+){
+  if( p->rc==SQLITE_OK ){
+    if( zSql ){
+      int rc = sqlite3_prepare_v3(p->pConfig->db, zSql, -1,
+          SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB,
+          ppStmt, 0);
+      /* If this prepare() call fails with SQLITE_ERROR, then one of the
+      ** %_idx or %_data tables has been removed or modified. Call this
+      ** corruption.  */
+      p->rc = (rc==SQLITE_ERROR ? SQLITE_CORRUPT : rc);
+    }else{
+      p->rc = SQLITE_NOMEM;
+    }
+  }
+  sqlite3_free(zSql);
+  return p->rc;
+}
+
+
+/*
+** INSERT OR REPLACE a record into the %_data table.
+*/
+static void fts5DataWrite(Fts5Index *p, i64 iRowid, const u8 *pData, int nData){
+  if( p->rc!=SQLITE_OK ) return;
+
+  if( p->pWriter==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pWriter, sqlite3_mprintf(
+          "REPLACE INTO '%q'.'%q_data'(id, block) VALUES(?,?)",
+          pConfig->zDb, pConfig->zName
+    ));
+    if( p->rc ) return;
+  }
+
+  sqlite3_bind_int64(p->pWriter, 1, iRowid);
+  sqlite3_bind_blob(p->pWriter, 2, pData, nData, SQLITE_STATIC);
+  sqlite3_step(p->pWriter);
+  p->rc = sqlite3_reset(p->pWriter);
+  sqlite3_bind_null(p->pWriter, 2);
+}
+
+/*
+** Execute the following SQL:
+**
+**     DELETE FROM %_data WHERE id BETWEEN $iFirst AND $iLast
+*/
+static void fts5DataDelete(Fts5Index *p, i64 iFirst, i64 iLast){
+  if( p->rc!=SQLITE_OK ) return;
+
+  if( p->pDeleter==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    char *zSql = sqlite3_mprintf(
+        "DELETE FROM '%q'.'%q_data' WHERE id>=? AND id<=?",
+          pConfig->zDb, pConfig->zName
+    );
+    if( fts5IndexPrepareStmt(p, &p->pDeleter, zSql) ) return;
+  }
+
+  sqlite3_bind_int64(p->pDeleter, 1, iFirst);
+  sqlite3_bind_int64(p->pDeleter, 2, iLast);
+  sqlite3_step(p->pDeleter);
+  p->rc = sqlite3_reset(p->pDeleter);
+}
+
+/*
+** Remove all records associated with segment iSegid.
+*/
+static void fts5DataRemoveSegment(Fts5Index *p, Fts5StructureSegment *pSeg){
+  int iSegid = pSeg->iSegid;
+  i64 iFirst = FTS5_SEGMENT_ROWID(iSegid, 0);
+  i64 iLast = FTS5_SEGMENT_ROWID(iSegid+1, 0)-1;
+  fts5DataDelete(p, iFirst, iLast);
+
+  if( pSeg->nPgTombstone ){
+    i64 iTomb1 = FTS5_TOMBSTONE_ROWID(iSegid, 0);
+    i64 iTomb2 = FTS5_TOMBSTONE_ROWID(iSegid, pSeg->nPgTombstone-1);
+    fts5DataDelete(p, iTomb1, iTomb2);
+  }
+  if( p->pIdxDeleter==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pIdxDeleter, sqlite3_mprintf(
+          "DELETE FROM '%q'.'%q_idx' WHERE segid=?",
+          pConfig->zDb, pConfig->zName
+    ));
+  }
+  if( p->rc==SQLITE_OK ){
+    sqlite3_bind_int(p->pIdxDeleter, 1, iSegid);
+    sqlite3_step(p->pIdxDeleter);
+    p->rc = sqlite3_reset(p->pIdxDeleter);
+  }
+}
+
+/*
+** Release a reference to an Fts5Structure object returned by an earlier
+** call to fts5StructureRead() or fts5StructureDecode().
+*/
+static void fts5StructureRelease(Fts5Structure *pStruct){
+  if( pStruct && 0>=(--pStruct->nRef) ){
+    int i;
+    assert( pStruct->nRef==0 );
+    for(i=0; i<pStruct->nLevel; i++){
+      sqlite3_free(pStruct->aLevel[i].aSeg);
+    }
+    sqlite3_free(pStruct);
+  }
+}
+
+static void fts5StructureRef(Fts5Structure *pStruct){
+  pStruct->nRef++;
+}
+
+static void *sqlite3Fts5StructureRef(Fts5Index *p){
+  fts5StructureRef(p->pStruct);
+  return (void*)p->pStruct;
+}
+static void sqlite3Fts5StructureRelease(void *p){
+  if( p ){
+    fts5StructureRelease((Fts5Structure*)p);
+  }
+}
+static int sqlite3Fts5StructureTest(Fts5Index *p, void *pStruct){
+  if( p->pStruct!=(Fts5Structure*)pStruct ){
+    return SQLITE_ABORT;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Ensure that structure object (*pp) is writable.
+**
+** This function is a no-op if (*pRc) is not SQLITE_OK when it is called. If
+** an error occurs, (*pRc) is set to an SQLite error code before returning.
+*/
+static void fts5StructureMakeWritable(int *pRc, Fts5Structure **pp){
+  Fts5Structure *p = *pp;
+  if( *pRc==SQLITE_OK && p->nRef>1 ){
+    i64 nByte = sizeof(Fts5Structure)+(p->nLevel-1)*sizeof(Fts5StructureLevel);
+    Fts5Structure *pNew;
+    pNew = (Fts5Structure*)sqlite3Fts5MallocZero(pRc, nByte);
+    if( pNew ){
+      int i;
+      memcpy(pNew, p, nByte);
+      for(i=0; i<p->nLevel; i++) pNew->aLevel[i].aSeg = 0;
+      for(i=0; i<p->nLevel; i++){
+        Fts5StructureLevel *pLvl = &pNew->aLevel[i];
+        nByte = sizeof(Fts5StructureSegment) * pNew->aLevel[i].nSeg;
+        pLvl->aSeg = (Fts5StructureSegment*)sqlite3Fts5MallocZero(pRc, nByte);
+        if( pLvl->aSeg==0 ){
+          for(i=0; i<p->nLevel; i++){
+            sqlite3_free(pNew->aLevel[i].aSeg);
+          }
+          sqlite3_free(pNew);
+          return;
+        }
+        memcpy(pLvl->aSeg, p->aLevel[i].aSeg, nByte);
+      }
+      p->nRef--;
+      pNew->nRef = 1;
+    }
+    *pp = pNew;
+  }
+}
+
+/*
+** Deserialize and return the structure record currently stored in serialized
+** form within buffer pData/nData.
+**
+** The Fts5Structure.aLevel[] and each Fts5StructureLevel.aSeg[] array
+** are over-allocated by one slot. This allows the structure contents
+** to be more easily edited.
+**
+** If an error occurs, *ppOut is set to NULL and an SQLite error code
+** returned. Otherwise, *ppOut is set to point to the new object and
+** SQLITE_OK returned.
+*/
+static int fts5StructureDecode(
+  const u8 *pData,                /* Buffer containing serialized structure */
+  int nData,                      /* Size of buffer pData in bytes */
+  int *piCookie,                  /* Configuration cookie value */
+  Fts5Structure **ppOut           /* OUT: Deserialized object */
+){
+  int rc = SQLITE_OK;
+  int i = 0;
+  int iLvl;
+  int nLevel = 0;
+  int nSegment = 0;
+  sqlite3_int64 nByte;            /* Bytes of space to allocate at pRet */
+  Fts5Structure *pRet = 0;        /* Structure object to return */
+  int bStructureV2 = 0;           /* True for FTS5_STRUCTURE_V2 */
+  u64 nOriginCntr = 0;            /* Largest origin value seen so far */
+
+  /* Grab the cookie value */
+  if( piCookie ) *piCookie = sqlite3Fts5Get32(pData);
+  i = 4;
+
+  /* Check if this is a V2 structure record. Set bStructureV2 if it is. */
+  if( 0==memcmp(&pData[i], FTS5_STRUCTURE_V2, 4) ){
+    i += 4;
+    bStructureV2 = 1;
+  }
+
+  /* Read the total number of levels and segments from the start of the
+  ** structure record.  */
+  i += fts5GetVarint32(&pData[i], nLevel);
+  i += fts5GetVarint32(&pData[i], nSegment);
+  if( nLevel>FTS5_MAX_SEGMENT   || nLevel<0
+   || nSegment>FTS5_MAX_SEGMENT || nSegment<0
+  ){
+    return FTS5_CORRUPT;
+  }
+  nByte = (
+      sizeof(Fts5Structure) +                    /* Main structure */
+      sizeof(Fts5StructureLevel) * (nLevel-1)    /* aLevel[] array */
+  );
+  pRet = (Fts5Structure*)sqlite3Fts5MallocZero(&rc, nByte);
+
+  if( pRet ){
+    pRet->nRef = 1;
+    pRet->nLevel = nLevel;
+    pRet->nSegment = nSegment;
+    i += sqlite3Fts5GetVarint(&pData[i], &pRet->nWriteCounter);
+
+    for(iLvl=0; rc==SQLITE_OK && iLvl<nLevel; iLvl++){
+      Fts5StructureLevel *pLvl = &pRet->aLevel[iLvl];
+      int nTotal = 0;
+      int iSeg;
+
+      if( i>=nData ){
+        rc = FTS5_CORRUPT;
+      }else{
+        i += fts5GetVarint32(&pData[i], pLvl->nMerge);
+        i += fts5GetVarint32(&pData[i], nTotal);
+        if( nTotal<pLvl->nMerge ) rc = FTS5_CORRUPT;
+        pLvl->aSeg = (Fts5StructureSegment*)sqlite3Fts5MallocZero(&rc,
+            nTotal * sizeof(Fts5StructureSegment)
+        );
+        nSegment -= nTotal;
+      }
+
+      if( rc==SQLITE_OK ){
+        pLvl->nSeg = nTotal;
+        for(iSeg=0; iSeg<nTotal; iSeg++){
+          Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
+          if( i>=nData ){
+            rc = FTS5_CORRUPT;
+            break;
+          }
+          assert( pSeg!=0 );
+          i += fts5GetVarint32(&pData[i], pSeg->iSegid);
+          i += fts5GetVarint32(&pData[i], pSeg->pgnoFirst);
+          i += fts5GetVarint32(&pData[i], pSeg->pgnoLast);
+          if( bStructureV2 ){
+            i += fts5GetVarint(&pData[i], &pSeg->iOrigin1);
+            i += fts5GetVarint(&pData[i], &pSeg->iOrigin2);
+            i += fts5GetVarint32(&pData[i], pSeg->nPgTombstone);
+            i += fts5GetVarint(&pData[i], &pSeg->nEntryTombstone);
+            i += fts5GetVarint(&pData[i], &pSeg->nEntry);
+            nOriginCntr = MAX(nOriginCntr, pSeg->iOrigin2);
+          }
+          if( pSeg->pgnoLast<pSeg->pgnoFirst ){
+            rc = FTS5_CORRUPT;
+            break;
+          }
+        }
+        if( iLvl>0 && pLvl[-1].nMerge && nTotal==0 ) rc = FTS5_CORRUPT;
+        if( iLvl==nLevel-1 && pLvl->nMerge ) rc = FTS5_CORRUPT;
+      }
+    }
+    if( nSegment!=0 && rc==SQLITE_OK ) rc = FTS5_CORRUPT;
+    if( bStructureV2 ){
+      pRet->nOriginCntr = nOriginCntr+1;
+    }
+
+    if( rc!=SQLITE_OK ){
+      fts5StructureRelease(pRet);
+      pRet = 0;
+    }
+  }
+
+  *ppOut = pRet;
+  return rc;
+}
+
+/*
+** Add a level to the Fts5Structure.aLevel[] array of structure object
+** (*ppStruct).
+*/
+static void fts5StructureAddLevel(int *pRc, Fts5Structure **ppStruct){
+  fts5StructureMakeWritable(pRc, ppStruct);
+  assert( (ppStruct!=0 && (*ppStruct)!=0) || (*pRc)!=SQLITE_OK );
+  if( *pRc==SQLITE_OK ){
+    Fts5Structure *pStruct = *ppStruct;
+    int nLevel = pStruct->nLevel;
+    sqlite3_int64 nByte = (
+        sizeof(Fts5Structure) +                  /* Main structure */
+        sizeof(Fts5StructureLevel) * (nLevel+1)  /* aLevel[] array */
+    );
+
+    pStruct = sqlite3_realloc64(pStruct, nByte);
+    if( pStruct ){
+      memset(&pStruct->aLevel[nLevel], 0, sizeof(Fts5StructureLevel));
+      pStruct->nLevel++;
+      *ppStruct = pStruct;
+    }else{
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+}
+
+/*
+** Extend level iLvl so that there is room for at least nExtra more
+** segments.
+*/
+static void fts5StructureExtendLevel(
+  int *pRc,
+  Fts5Structure *pStruct,
+  int iLvl,
+  int nExtra,
+  int bInsert
+){
+  if( *pRc==SQLITE_OK ){
+    Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
+    Fts5StructureSegment *aNew;
+    sqlite3_int64 nByte;
+
+    nByte = (pLvl->nSeg + nExtra) * sizeof(Fts5StructureSegment);
+    aNew = sqlite3_realloc64(pLvl->aSeg, nByte);
+    if( aNew ){
+      if( bInsert==0 ){
+        memset(&aNew[pLvl->nSeg], 0, sizeof(Fts5StructureSegment) * nExtra);
+      }else{
+        int nMove = pLvl->nSeg * sizeof(Fts5StructureSegment);
+        memmove(&aNew[nExtra], aNew, nMove);
+        memset(aNew, 0, sizeof(Fts5StructureSegment) * nExtra);
+      }
+      pLvl->aSeg = aNew;
+    }else{
+      *pRc = SQLITE_NOMEM;
+    }
+  }
+}
+
+static Fts5Structure *fts5StructureReadUncached(Fts5Index *p){
+  Fts5Structure *pRet = 0;
+  Fts5Config *pConfig = p->pConfig;
+  int iCookie;                    /* Configuration cookie */
+  Fts5Data *pData;
+
+  pData = fts5DataRead(p, FTS5_STRUCTURE_ROWID);
+  if( p->rc==SQLITE_OK ){
+    /* TODO: Do we need this if the leaf-index is appended? Probably... */
+    memset(&pData->p[pData->nn], 0, FTS5_DATA_PADDING);
+    p->rc = fts5StructureDecode(pData->p, pData->nn, &iCookie, &pRet);
+    if( p->rc==SQLITE_OK && (pConfig->pgsz==0 || pConfig->iCookie!=iCookie) ){
+      p->rc = sqlite3Fts5ConfigLoad(pConfig, iCookie);
+    }
+    fts5DataRelease(pData);
+    if( p->rc!=SQLITE_OK ){
+      fts5StructureRelease(pRet);
+      pRet = 0;
+    }
+  }
+
+  return pRet;
+}
+
+static i64 fts5IndexDataVersion(Fts5Index *p){
+  i64 iVersion = 0;
+
+  if( p->rc==SQLITE_OK ){
+    if( p->pDataVersion==0 ){
+      p->rc = fts5IndexPrepareStmt(p, &p->pDataVersion,
+          sqlite3_mprintf("PRAGMA %Q.data_version", p->pConfig->zDb)
+          );
+      if( p->rc ) return 0;
+    }
+
+    if( SQLITE_ROW==sqlite3_step(p->pDataVersion) ){
+      iVersion = sqlite3_column_int64(p->pDataVersion, 0);
+    }
+    p->rc = sqlite3_reset(p->pDataVersion);
+  }
+
+  return iVersion;
+}
+
+/*
+** Read, deserialize and return the structure record.
+**
+** The Fts5Structure.aLevel[] and each Fts5StructureLevel.aSeg[] array
+** are over-allocated as described for function fts5StructureDecode()
+** above.
+**
+** If an error occurs, NULL is returned and an error code left in the
+** Fts5Index handle. If an error has already occurred when this function
+** is called, it is a no-op.
+*/
+static Fts5Structure *fts5StructureRead(Fts5Index *p){
+
+  if( p->pStruct==0 ){
+    p->iStructVersion = fts5IndexDataVersion(p);
+    if( p->rc==SQLITE_OK ){
+      p->pStruct = fts5StructureReadUncached(p);
+    }
+  }
+
+#if 0
+  else{
+    Fts5Structure *pTest = fts5StructureReadUncached(p);
+    if( pTest ){
+      int i, j;
+      assert_nc( p->pStruct->nSegment==pTest->nSegment );
+      assert_nc( p->pStruct->nLevel==pTest->nLevel );
+      for(i=0; i<pTest->nLevel; i++){
+        assert_nc( p->pStruct->aLevel[i].nMerge==pTest->aLevel[i].nMerge );
+        assert_nc( p->pStruct->aLevel[i].nSeg==pTest->aLevel[i].nSeg );
+        for(j=0; j<pTest->aLevel[i].nSeg; j++){
+          Fts5StructureSegment *p1 = &pTest->aLevel[i].aSeg[j];
+          Fts5StructureSegment *p2 = &p->pStruct->aLevel[i].aSeg[j];
+          assert_nc( p1->iSegid==p2->iSegid );
+          assert_nc( p1->pgnoFirst==p2->pgnoFirst );
+          assert_nc( p1->pgnoLast==p2->pgnoLast );
+        }
+      }
+      fts5StructureRelease(pTest);
+    }
+  }
+#endif
+
+  if( p->rc!=SQLITE_OK ) return 0;
+  assert( p->iStructVersion!=0 );
+  assert( p->pStruct!=0 );
+  fts5StructureRef(p->pStruct);
+  return p->pStruct;
+}
+
+static void fts5StructureInvalidate(Fts5Index *p){
+  if( p->pStruct ){
+    fts5StructureRelease(p->pStruct);
+    p->pStruct = 0;
+  }
+}
+
+/*
+** Return the total number of segments in index structure pStruct. This
+** function is only ever used as part of assert() conditions.
+*/
+#ifdef SQLITE_DEBUG
+static int fts5StructureCountSegments(Fts5Structure *pStruct){
+  int nSegment = 0;               /* Total number of segments */
+  if( pStruct ){
+    int iLvl;                     /* Used to iterate through levels */
+    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+      nSegment += pStruct->aLevel[iLvl].nSeg;
+    }
+  }
+
+  return nSegment;
+}
+#endif
+
+#define fts5BufferSafeAppendBlob(pBuf, pBlob, nBlob) {     \
+  assert( (pBuf)->nSpace>=((pBuf)->n+nBlob) );             \
+  memcpy(&(pBuf)->p[(pBuf)->n], pBlob, nBlob);             \
+  (pBuf)->n += nBlob;                                      \
+}
+
+#define fts5BufferSafeAppendVarint(pBuf, iVal) {                \
+  (pBuf)->n += sqlite3Fts5PutVarint(&(pBuf)->p[(pBuf)->n], (iVal));  \
+  assert( (pBuf)->nSpace>=(pBuf)->n );                          \
+}
+
+
+/*
+** Serialize and store the "structure" record.
+**
+** If an error occurs, leave an error code in the Fts5Index object. If an
+** error has already occurred, this function is a no-op.
+*/
+static void fts5StructureWrite(Fts5Index *p, Fts5Structure *pStruct){
+  if( p->rc==SQLITE_OK ){
+    Fts5Buffer buf;               /* Buffer to serialize record into */
+    int iLvl;                     /* Used to iterate through levels */
+    int iCookie;                  /* Cookie value to store */
+    int nHdr = (pStruct->nOriginCntr>0 ? (4+4+9+9+9) : (4+9+9));
+
+    assert( pStruct->nSegment==fts5StructureCountSegments(pStruct) );
+    memset(&buf, 0, sizeof(Fts5Buffer));
+
+    /* Append the current configuration cookie */
+    iCookie = p->pConfig->iCookie;
+    if( iCookie<0 ) iCookie = 0;
+
+    if( 0==sqlite3Fts5BufferSize(&p->rc, &buf, nHdr) ){
+      sqlite3Fts5Put32(buf.p, iCookie);
+      buf.n = 4;
+      if( pStruct->nOriginCntr>0 ){
+        fts5BufferSafeAppendBlob(&buf, FTS5_STRUCTURE_V2, 4);
+      }
+      fts5BufferSafeAppendVarint(&buf, pStruct->nLevel);
+      fts5BufferSafeAppendVarint(&buf, pStruct->nSegment);
+      fts5BufferSafeAppendVarint(&buf, (i64)pStruct->nWriteCounter);
+    }
+
+    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+      int iSeg;                     /* Used to iterate through segments */
+      Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
+      fts5BufferAppendVarint(&p->rc, &buf, pLvl->nMerge);
+      fts5BufferAppendVarint(&p->rc, &buf, pLvl->nSeg);
+      assert( pLvl->nMerge<=pLvl->nSeg );
+
+      for(iSeg=0; iSeg<pLvl->nSeg; iSeg++){
+        Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
+        fts5BufferAppendVarint(&p->rc, &buf, pSeg->iSegid);
+        fts5BufferAppendVarint(&p->rc, &buf, pSeg->pgnoFirst);
+        fts5BufferAppendVarint(&p->rc, &buf, pSeg->pgnoLast);
+        if( pStruct->nOriginCntr>0 ){
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->iOrigin1);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->iOrigin2);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->nPgTombstone);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->nEntryTombstone);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->nEntry);
+        }
+      }
+    }
+
+    fts5DataWrite(p, FTS5_STRUCTURE_ROWID, buf.p, buf.n);
+    fts5BufferFree(&buf);
+  }
+}
+
+#if 0
+static void fts5DebugStructure(int*,Fts5Buffer*,Fts5Structure*);
+static void fts5PrintStructure(const char *zCaption, Fts5Structure *pStruct){
+  int rc = SQLITE_OK;
+  Fts5Buffer buf;
+  memset(&buf, 0, sizeof(buf));
+  fts5DebugStructure(&rc, &buf, pStruct);
+  fprintf(stdout, "%s: %s\n", zCaption, buf.p);
+  fflush(stdout);
+  fts5BufferFree(&buf);
+}
+#else
+# define fts5PrintStructure(x,y)
+#endif
+
+static int fts5SegmentSize(Fts5StructureSegment *pSeg){
+  return 1 + pSeg->pgnoLast - pSeg->pgnoFirst;
+}
+
+/*
+** Return a copy of index structure pStruct. Except, promote as many
+** segments as possible to level iPromote. If an OOM occurs, NULL is
+** returned.
+*/
+static void fts5StructurePromoteTo(
+  Fts5Index *p,
+  int iPromote,
+  int szPromote,
+  Fts5Structure *pStruct
+){
+  int il, is;
+  Fts5StructureLevel *pOut = &pStruct->aLevel[iPromote];
+
+  if( pOut->nMerge==0 ){
+    for(il=iPromote+1; il<pStruct->nLevel; il++){
+      Fts5StructureLevel *pLvl = &pStruct->aLevel[il];
+      if( pLvl->nMerge ) return;
+      for(is=pLvl->nSeg-1; is>=0; is--){
+        int sz = fts5SegmentSize(&pLvl->aSeg[is]);
+        if( sz>szPromote ) return;
+        fts5StructureExtendLevel(&p->rc, pStruct, iPromote, 1, 1);
+        if( p->rc ) return;
+        memcpy(pOut->aSeg, &pLvl->aSeg[is], sizeof(Fts5StructureSegment));
+        pOut->nSeg++;
+        pLvl->nSeg--;
+      }
+    }
+  }
+}
+
+/*
+** A new segment has just been written to level iLvl of index structure
+** pStruct. This function determines if any segments should be promoted
+** as a result. Segments are promoted in two scenarios:
+**
+**   a) If the segment just written is smaller than one or more segments
+**      within the previous populated level, it is promoted to the previous
+**      populated level.
+**
+**   b) If the segment just written is larger than the newest segment on
+**      the next populated level, then that segment, and any other adjacent
+**      segments that are also smaller than the one just written, are
+**      promoted.
+**
+** If one or more segments are promoted, the structure object is updated
+** to reflect this.
+*/
+static void fts5StructurePromote(
+  Fts5Index *p,                   /* FTS5 backend object */
+  int iLvl,                       /* Index level just updated */
+  Fts5Structure *pStruct          /* Index structure */
+){
+  if( p->rc==SQLITE_OK ){
+    int iTst;
+    int iPromote = -1;
+    int szPromote = 0;            /* Promote anything this size or smaller */
+    Fts5StructureSegment *pSeg;   /* Segment just written */
+    int szSeg;                    /* Size of segment just written */
+    int nSeg = pStruct->aLevel[iLvl].nSeg;
+
+    if( nSeg==0 ) return;
+    pSeg = &pStruct->aLevel[iLvl].aSeg[pStruct->aLevel[iLvl].nSeg-1];
+    szSeg = (1 + pSeg->pgnoLast - pSeg->pgnoFirst);
+
+    /* Check for condition (a) */
+    for(iTst=iLvl-1; iTst>=0 && pStruct->aLevel[iTst].nSeg==0; iTst--);
+    if( iTst>=0 ){
+      int i;
+      int szMax = 0;
+      Fts5StructureLevel *pTst = &pStruct->aLevel[iTst];
+      assert( pTst->nMerge==0 );
+      for(i=0; i<pTst->nSeg; i++){
+        int sz = pTst->aSeg[i].pgnoLast - pTst->aSeg[i].pgnoFirst + 1;
+        if( sz>szMax ) szMax = sz;
+      }
+      if( szMax>=szSeg ){
+        /* Condition (a) is true. Promote the newest segment on level
+        ** iLvl to level iTst.  */
+        iPromote = iTst;
+        szPromote = szMax;
+      }
+    }
+
+    /* If condition (a) is not met, assume (b) is true. StructurePromoteTo()
+    ** is a no-op if it is not.  */
+    if( iPromote<0 ){
+      iPromote = iLvl;
+      szPromote = szSeg;
+    }
+    fts5StructurePromoteTo(p, iPromote, szPromote, pStruct);
+  }
+}
+
+
+/*
+** Advance the iterator passed as the only argument. If the end of the
+** doclist-index page is reached, return non-zero.
+*/
+static int fts5DlidxLvlNext(Fts5DlidxLvl *pLvl){
+  Fts5Data *pData = pLvl->pData;
+
+  if( pLvl->iOff==0 ){
+    assert( pLvl->bEof==0 );
+    pLvl->iOff = 1;
+    pLvl->iOff += fts5GetVarint32(&pData->p[1], pLvl->iLeafPgno);
+    pLvl->iOff += fts5GetVarint(&pData->p[pLvl->iOff], (u64*)&pLvl->iRowid);
+    pLvl->iFirstOff = pLvl->iOff;
+  }else{
+    int iOff;
+    for(iOff=pLvl->iOff; iOff<pData->nn; iOff++){
+      if( pData->p[iOff] ) break;
+    }
+
+    if( iOff<pData->nn ){
+      u64 iVal;
+      pLvl->iLeafPgno += (iOff - pLvl->iOff) + 1;
+      iOff += fts5GetVarint(&pData->p[iOff], &iVal);
+      pLvl->iRowid += iVal;
+      pLvl->iOff = iOff;
+    }else{
+      pLvl->bEof = 1;
+    }
+  }
+
+  return pLvl->bEof;
+}
+
+/*
+** Advance the iterator passed as the only argument.
+*/
+static int fts5DlidxIterNextR(Fts5Index *p, Fts5DlidxIter *pIter, int iLvl){
+  Fts5DlidxLvl *pLvl = &pIter->aLvl[iLvl];
+
+  assert( iLvl<pIter->nLvl );
+  if( fts5DlidxLvlNext(pLvl) ){
+    if( (iLvl+1) < pIter->nLvl ){
+      fts5DlidxIterNextR(p, pIter, iLvl+1);
+      if( pLvl[1].bEof==0 ){
+        fts5DataRelease(pLvl->pData);
+        memset(pLvl, 0, sizeof(Fts5DlidxLvl));
+        pLvl->pData = fts5DataRead(p,
+            FTS5_DLIDX_ROWID(pIter->iSegid, iLvl, pLvl[1].iLeafPgno)
+        );
+        if( pLvl->pData ) fts5DlidxLvlNext(pLvl);
+      }
+    }
+  }
+
+  return pIter->aLvl[0].bEof;
+}
+static int fts5DlidxIterNext(Fts5Index *p, Fts5DlidxIter *pIter){
+  return fts5DlidxIterNextR(p, pIter, 0);
+}
+
+/*
+** The iterator passed as the first argument has the following fields set
+** as follows. This function sets up the rest of the iterator so that it
+** points to the first rowid in the doclist-index.
+**
+**   pData:
+**     pointer to doclist-index record,
+**
+** When this function is called pIter->iLeafPgno is the page number the
+** doclist is associated with (the one featuring the term).
+*/
+static int fts5DlidxIterFirst(Fts5DlidxIter *pIter){
+  int i;
+  for(i=0; i<pIter->nLvl; i++){
+    fts5DlidxLvlNext(&pIter->aLvl[i]);
+  }
+  return pIter->aLvl[0].bEof;
+}
+
+
+static int fts5DlidxIterEof(Fts5Index *p, Fts5DlidxIter *pIter){
+  return p->rc!=SQLITE_OK || pIter->aLvl[0].bEof;
+}
+
+static void fts5DlidxIterLast(Fts5Index *p, Fts5DlidxIter *pIter){
+  int i;
+
+  /* Advance each level to the last entry on the last page */
+  for(i=pIter->nLvl-1; p->rc==SQLITE_OK && i>=0; i--){
+    Fts5DlidxLvl *pLvl = &pIter->aLvl[i];
+    while( fts5DlidxLvlNext(pLvl)==0 );
+    pLvl->bEof = 0;
+
+    if( i>0 ){
+      Fts5DlidxLvl *pChild = &pLvl[-1];
+      fts5DataRelease(pChild->pData);
+      memset(pChild, 0, sizeof(Fts5DlidxLvl));
+      pChild->pData = fts5DataRead(p,
+          FTS5_DLIDX_ROWID(pIter->iSegid, i-1, pLvl->iLeafPgno)
+      );
+    }
+  }
+}
+
+/*
+** Move the iterator passed as the only argument to the previous entry.
+*/
+static int fts5DlidxLvlPrev(Fts5DlidxLvl *pLvl){
+  int iOff = pLvl->iOff;
+
+  assert( pLvl->bEof==0 );
+  if( iOff<=pLvl->iFirstOff ){
+    pLvl->bEof = 1;
+  }else{
+    u8 *a = pLvl->pData->p;
+
+    pLvl->iOff = 0;
+    fts5DlidxLvlNext(pLvl);
+    while( 1 ){
+      int nZero = 0;
+      int ii = pLvl->iOff;
+      u64 delta = 0;
+
+      while( a[ii]==0 ){
+        nZero++;
+        ii++;
+      }
+      ii += sqlite3Fts5GetVarint(&a[ii], &delta);
+
+      if( ii>=iOff ) break;
+      pLvl->iLeafPgno += nZero+1;
+      pLvl->iRowid += delta;
+      pLvl->iOff = ii;
+    }
+  }
+
+  return pLvl->bEof;
+}
+
+static int fts5DlidxIterPrevR(Fts5Index *p, Fts5DlidxIter *pIter, int iLvl){
+  Fts5DlidxLvl *pLvl = &pIter->aLvl[iLvl];
+
+  assert( iLvl<pIter->nLvl );
+  if( fts5DlidxLvlPrev(pLvl) ){
+    if( (iLvl+1) < pIter->nLvl ){
+      fts5DlidxIterPrevR(p, pIter, iLvl+1);
+      if( pLvl[1].bEof==0 ){
+        fts5DataRelease(pLvl->pData);
+        memset(pLvl, 0, sizeof(Fts5DlidxLvl));
+        pLvl->pData = fts5DataRead(p,
+            FTS5_DLIDX_ROWID(pIter->iSegid, iLvl, pLvl[1].iLeafPgno)
+        );
+        if( pLvl->pData ){
+          while( fts5DlidxLvlNext(pLvl)==0 );
+          pLvl->bEof = 0;
+        }
+      }
+    }
+  }
+
+  return pIter->aLvl[0].bEof;
+}
+static int fts5DlidxIterPrev(Fts5Index *p, Fts5DlidxIter *pIter){
+  return fts5DlidxIterPrevR(p, pIter, 0);
+}
+
+/*
+** Free a doclist-index iterator object allocated by fts5DlidxIterInit().
+*/
+static void fts5DlidxIterFree(Fts5DlidxIter *pIter){
+  if( pIter ){
+    int i;
+    for(i=0; i<pIter->nLvl; i++){
+      fts5DataRelease(pIter->aLvl[i].pData);
+    }
+    sqlite3_free(pIter);
+  }
+}
+
+static Fts5DlidxIter *fts5DlidxIterInit(
+  Fts5Index *p,                   /* Fts5 Backend to iterate within */
+  int bRev,                       /* True for ORDER BY ASC */
+  int iSegid,                     /* Segment id */
+  int iLeafPg                     /* Leaf page number to load dlidx for */
+){
+  Fts5DlidxIter *pIter = 0;
+  int i;
+  int bDone = 0;
+
+  for(i=0; p->rc==SQLITE_OK && bDone==0; i++){
+    sqlite3_int64 nByte = sizeof(Fts5DlidxIter) + i * sizeof(Fts5DlidxLvl);
+    Fts5DlidxIter *pNew;
+
+    pNew = (Fts5DlidxIter*)sqlite3_realloc64(pIter, nByte);
+    if( pNew==0 ){
+      p->rc = SQLITE_NOMEM;
+    }else{
+      i64 iRowid = FTS5_DLIDX_ROWID(iSegid, i, iLeafPg);
+      Fts5DlidxLvl *pLvl = &pNew->aLvl[i];
+      pIter = pNew;
+      memset(pLvl, 0, sizeof(Fts5DlidxLvl));
+      pLvl->pData = fts5DataRead(p, iRowid);
+      if( pLvl->pData && (pLvl->pData->p[0] & 0x0001)==0 ){
+        bDone = 1;
+      }
+      pIter->nLvl = i+1;
+    }
+  }
+
+  if( p->rc==SQLITE_OK ){
+    pIter->iSegid = iSegid;
+    if( bRev==0 ){
+      fts5DlidxIterFirst(pIter);
+    }else{
+      fts5DlidxIterLast(p, pIter);
+    }
+  }
+
+  if( p->rc!=SQLITE_OK ){
+    fts5DlidxIterFree(pIter);
+    pIter = 0;
+  }
+
+  return pIter;
+}
+
+static i64 fts5DlidxIterRowid(Fts5DlidxIter *pIter){
+  return pIter->aLvl[0].iRowid;
+}
+static int fts5DlidxIterPgno(Fts5DlidxIter *pIter){
+  return pIter->aLvl[0].iLeafPgno;
+}
+
+/*
+** Load the next leaf page into the segment iterator.
+*/
+static void fts5SegIterNextPage(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter              /* Iterator to advance to next page */
+){
+  Fts5Data *pLeaf;
+  Fts5StructureSegment *pSeg = pIter->pSeg;
+  fts5DataRelease(pIter->pLeaf);
+  pIter->iLeafPgno++;
+  if( pIter->pNextLeaf ){
+    pIter->pLeaf = pIter->pNextLeaf;
+    pIter->pNextLeaf = 0;
+  }else if( pIter->iLeafPgno<=pSeg->pgnoLast ){
+    pIter->pLeaf = fts5LeafRead(p,
+        FTS5_SEGMENT_ROWID(pSeg->iSegid, pIter->iLeafPgno)
+    );
+  }else{
+    pIter->pLeaf = 0;
+  }
+  pLeaf = pIter->pLeaf;
+
+  if( pLeaf ){
+    pIter->iPgidxOff = pLeaf->szLeaf;
+    if( fts5LeafIsTermless(pLeaf) ){
+      pIter->iEndofDoclist = pLeaf->nn+1;
+    }else{
+      pIter->iPgidxOff += fts5GetVarint32(&pLeaf->p[pIter->iPgidxOff],
+          pIter->iEndofDoclist
+      );
+    }
+  }
+}
+
+/*
+** Argument p points to a buffer containing a varint to be interpreted as a
+** position list size field. Read the varint and return the number of bytes
+** read. Before returning, set *pnSz to the number of bytes in the position
+** list, and *pbDel to true if the delete flag is set, or false otherwise.
+*/
+static int fts5GetPoslistSize(const u8 *p, int *pnSz, int *pbDel){
+  int nSz;
+  int n = 0;
+  fts5FastGetVarint32(p, n, nSz);
+  assert_nc( nSz>=0 );
+  *pnSz = nSz/2;
+  *pbDel = nSz & 0x0001;
+  return n;
+}
+
+/*
+** Fts5SegIter.iLeafOffset currently points to the first byte of a
+** position-list size field. Read the value of the field and store it
+** in the following variables:
+**
+**   Fts5SegIter.nPos
+**   Fts5SegIter.bDel
+**
+** Leave Fts5SegIter.iLeafOffset pointing to the first byte of the
+** position list content (if any).
+*/
+static void fts5SegIterLoadNPos(Fts5Index *p, Fts5SegIter *pIter){
+  if( p->rc==SQLITE_OK ){
+    int iOff = pIter->iLeafOffset;  /* Offset to read at */
+    ASSERT_SZLEAF_OK(pIter->pLeaf);
+    if( p->pConfig->eDetail==FTS5_DETAIL_NONE ){
+      int iEod = MIN(pIter->iEndofDoclist, pIter->pLeaf->szLeaf);
+      pIter->bDel = 0;
+      pIter->nPos = 1;
+      if( iOff<iEod && pIter->pLeaf->p[iOff]==0 ){
+        pIter->bDel = 1;
+        iOff++;
+        if( iOff<iEod && pIter->pLeaf->p[iOff]==0 ){
+          pIter->nPos = 1;
+          iOff++;
+        }else{
+          pIter->nPos = 0;
+        }
+      }
+    }else{
+      int nSz;
+      fts5FastGetVarint32(pIter->pLeaf->p, iOff, nSz);
+      pIter->bDel = (nSz & 0x0001);
+      pIter->nPos = nSz>>1;
+      assert_nc( pIter->nPos>=0 );
+    }
+    pIter->iLeafOffset = iOff;
+  }
+}
+
+static void fts5SegIterLoadRowid(Fts5Index *p, Fts5SegIter *pIter){
+  u8 *a = pIter->pLeaf->p;        /* Buffer to read data from */
+  i64 iOff = pIter->iLeafOffset;
+
+  ASSERT_SZLEAF_OK(pIter->pLeaf);
+  while( iOff>=pIter->pLeaf->szLeaf ){
+    fts5SegIterNextPage(p, pIter);
+    if( pIter->pLeaf==0 ){
+      if( p->rc==SQLITE_OK ) p->rc = FTS5_CORRUPT;
+      return;
+    }
+    iOff = 4;
+    a = pIter->pLeaf->p;
+  }
+  iOff += sqlite3Fts5GetVarint(&a[iOff], (u64*)&pIter->iRowid);
+  pIter->iLeafOffset = iOff;
+}
+
+/*
+** Fts5SegIter.iLeafOffset currently points to the first byte of the
+** "nSuffix" field of a term. Function parameter nKeep contains the value
+** of the "nPrefix" field (if there was one - it is passed 0 if this is
+** the first term in the segment).
+**
+** This function populates:
+**
+**   Fts5SegIter.term
+**   Fts5SegIter.rowid
+**
+** accordingly and leaves (Fts5SegIter.iLeafOffset) set to the content of
+** the first position list. The position list belonging to document
+** (Fts5SegIter.iRowid).
+*/
+static void fts5SegIterLoadTerm(Fts5Index *p, Fts5SegIter *pIter, int nKeep){
+  u8 *a = pIter->pLeaf->p;        /* Buffer to read data from */
+  i64 iOff = pIter->iLeafOffset;  /* Offset to read at */
+  int nNew;                       /* Bytes of new data */
+
+  iOff += fts5GetVarint32(&a[iOff], nNew);
+  if( iOff+nNew>pIter->pLeaf->szLeaf || nKeep>pIter->term.n || nNew==0 ){
+    p->rc = FTS5_CORRUPT;
+    return;
+  }
+  pIter->term.n = nKeep;
+  fts5BufferAppendBlob(&p->rc, &pIter->term, nNew, &a[iOff]);
+  assert( pIter->term.n<=pIter->term.nSpace );
+  iOff += nNew;
+  pIter->iTermLeafOffset = iOff;
+  pIter->iTermLeafPgno = pIter->iLeafPgno;
+  pIter->iLeafOffset = iOff;
+
+  if( pIter->iPgidxOff>=pIter->pLeaf->nn ){
+    pIter->iEndofDoclist = pIter->pLeaf->nn+1;
+  }else{
+    int nExtra;
+    pIter->iPgidxOff += fts5GetVarint32(&a[pIter->iPgidxOff], nExtra);
+    pIter->iEndofDoclist += nExtra;
+  }
+
+  fts5SegIterLoadRowid(p, pIter);
+}
+
+static void fts5SegIterNext(Fts5Index*, Fts5SegIter*, int*);
+static void fts5SegIterNext_Reverse(Fts5Index*, Fts5SegIter*, int*);
+static void fts5SegIterNext_None(Fts5Index*, Fts5SegIter*, int*);
+
+static void fts5SegIterSetNext(Fts5Index *p, Fts5SegIter *pIter){
+  if( pIter->flags & FTS5_SEGITER_REVERSE ){
+    pIter->xNext = fts5SegIterNext_Reverse;
+  }else if( p->pConfig->eDetail==FTS5_DETAIL_NONE ){
+    pIter->xNext = fts5SegIterNext_None;
+  }else{
+    pIter->xNext = fts5SegIterNext;
+  }
+}
+
+/*
+** Allocate a tombstone hash page array object (pIter->pTombArray) for
+** the iterator passed as the second argument. If an OOM error occurs,
+** leave an error in the Fts5Index object.
+*/
+static void fts5SegIterAllocTombstone(Fts5Index *p, Fts5SegIter *pIter){
+  const int nTomb = pIter->pSeg->nPgTombstone;
+  if( nTomb>0 ){
+    int nByte = nTomb * sizeof(Fts5Data*) + sizeof(Fts5TombstoneArray);
+    Fts5TombstoneArray *pNew;
+    pNew = (Fts5TombstoneArray*)sqlite3Fts5MallocZero(&p->rc, nByte);
+    if( pNew ){
+      pNew->nTombstone = nTomb;
+      pNew->nRef = 1;
+      pIter->pTombArray = pNew;
+    }
+  }
+}
+
+/*
+** Initialize the iterator object pIter to iterate through the entries in
+** segment pSeg. The iterator is left pointing to the first entry when
+** this function returns.
+**
+** If an error occurs, Fts5Index.rc is set to an appropriate error code. If
+** an error has already occurred when this function is called, it is a no-op.
+*/
+static void fts5SegIterInit(
+  Fts5Index *p,                   /* FTS index object */
+  Fts5StructureSegment *pSeg,     /* Description of segment */
+  Fts5SegIter *pIter              /* Object to populate */
+){
+  if( pSeg->pgnoFirst==0 ){
+    /* This happens if the segment is being used as an input to an incremental
+    ** merge and all data has already been "trimmed". See function
+    ** fts5TrimSegments() for details. In this case leave the iterator empty.
+    ** The caller will see the (pIter->pLeaf==0) and assume the iterator is
+    ** at EOF already. */
+    assert( pIter->pLeaf==0 );
+    return;
+  }
+
+  if( p->rc==SQLITE_OK ){
+    memset(pIter, 0, sizeof(*pIter));
+    fts5SegIterSetNext(p, pIter);
+    pIter->pSeg = pSeg;
+    pIter->iLeafPgno = pSeg->pgnoFirst-1;
+    do {
+      fts5SegIterNextPage(p, pIter);
+    }while( p->rc==SQLITE_OK && pIter->pLeaf && pIter->pLeaf->nn==4 );
+  }
+
+  if( p->rc==SQLITE_OK && pIter->pLeaf ){
+    pIter->iLeafOffset = 4;
+    assert( pIter->pLeaf!=0 );
+    assert_nc( pIter->pLeaf->nn>4 );
+    assert_nc( fts5LeafFirstTermOff(pIter->pLeaf)==4 );
+    pIter->iPgidxOff = pIter->pLeaf->szLeaf+1;
+    fts5SegIterLoadTerm(p, pIter, 0);
+    fts5SegIterLoadNPos(p, pIter);
+    fts5SegIterAllocTombstone(p, pIter);
+  }
+}
+
+/*
+** This function is only ever called on iterators created by calls to
+** Fts5IndexQuery() with the FTS5INDEX_QUERY_DESC flag set.
+**
+** The iterator is in an unusual state when this function is called: the
+** Fts5SegIter.iLeafOffset variable is set to the offset of the start of
+** the position-list size field for the first relevant rowid on the page.
+** Fts5SegIter.rowid is set, but nPos and bDel are not.
+**
+** This function advances the iterator so that it points to the last
+** relevant rowid on the page and, if necessary, initializes the
+** aRowidOffset[] and iRowidOffset variables. At this point the iterator
+** is in its regular state - Fts5SegIter.iLeafOffset points to the first
+** byte of the position list content associated with said rowid.
+*/
+static void fts5SegIterReverseInitPage(Fts5Index *p, Fts5SegIter *pIter){
+  int eDetail = p->pConfig->eDetail;
+  int n = pIter->pLeaf->szLeaf;
+  int i = pIter->iLeafOffset;
+  u8 *a = pIter->pLeaf->p;
+  int iRowidOffset = 0;
+
+  if( n>pIter->iEndofDoclist ){
+    n = pIter->iEndofDoclist;
+  }
+
+  ASSERT_SZLEAF_OK(pIter->pLeaf);
+  while( 1 ){
+    u64 iDelta = 0;
+
+    if( eDetail==FTS5_DETAIL_NONE ){
+      /* todo */
+      if( i<n && a[i]==0 ){
+        i++;
+        if( i<n && a[i]==0 ) i++;
+      }
+    }else{
+      int nPos;
+      int bDummy;
+      i += fts5GetPoslistSize(&a[i], &nPos, &bDummy);
+      i += nPos;
+    }
+    if( i>=n ) break;
+    i += fts5GetVarint(&a[i], &iDelta);
+    pIter->iRowid += iDelta;
+
+    /* If necessary, grow the pIter->aRowidOffset[] array. */
+    if( iRowidOffset>=pIter->nRowidOffset ){
+      int nNew = pIter->nRowidOffset + 8;
+      int *aNew = (int*)sqlite3_realloc64(pIter->aRowidOffset,nNew*sizeof(int));
+      if( aNew==0 ){
+        p->rc = SQLITE_NOMEM;
+        break;
+      }
+      pIter->aRowidOffset = aNew;
+      pIter->nRowidOffset = nNew;
+    }
+
+    pIter->aRowidOffset[iRowidOffset++] = pIter->iLeafOffset;
+    pIter->iLeafOffset = i;
+  }
+  pIter->iRowidOffset = iRowidOffset;
+  fts5SegIterLoadNPos(p, pIter);
+}
+
+/*
+**
+*/
+static void fts5SegIterReverseNewPage(Fts5Index *p, Fts5SegIter *pIter){
+  assert( pIter->flags & FTS5_SEGITER_REVERSE );
+  assert( pIter->flags & FTS5_SEGITER_ONETERM );
+
+  fts5DataRelease(pIter->pLeaf);
+  pIter->pLeaf = 0;
+  while( p->rc==SQLITE_OK && pIter->iLeafPgno>pIter->iTermLeafPgno ){
+    Fts5Data *pNew;
+    pIter->iLeafPgno--;
+    pNew = fts5DataRead(p, FTS5_SEGMENT_ROWID(
+          pIter->pSeg->iSegid, pIter->iLeafPgno
+    ));
+    if( pNew ){
+      /* iTermLeafOffset may be equal to szLeaf if the term is the last
+      ** thing on the page - i.e. the first rowid is on the following page.
+      ** In this case leave pIter->pLeaf==0, this iterator is at EOF. */
+      if( pIter->iLeafPgno==pIter->iTermLeafPgno ){
+        assert( pIter->pLeaf==0 );
+        if( pIter->iTermLeafOffset<pNew->szLeaf ){
+          pIter->pLeaf = pNew;
+          pIter->iLeafOffset = pIter->iTermLeafOffset;
+        }
+      }else{
+        int iRowidOff;
+        iRowidOff = fts5LeafFirstRowidOff(pNew);
+        if( iRowidOff ){
+          if( iRowidOff>=pNew->szLeaf ){
+            p->rc = FTS5_CORRUPT;
+          }else{
+            pIter->pLeaf = pNew;
+            pIter->iLeafOffset = iRowidOff;
+          }
+        }
+      }
+
+      if( pIter->pLeaf ){
+        u8 *a = &pIter->pLeaf->p[pIter->iLeafOffset];
+        pIter->iLeafOffset += fts5GetVarint(a, (u64*)&pIter->iRowid);
+        break;
+      }else{
+        fts5DataRelease(pNew);
+      }
+    }
+  }
+
+  if( pIter->pLeaf ){
+    pIter->iEndofDoclist = pIter->pLeaf->nn+1;
+    fts5SegIterReverseInitPage(p, pIter);
+  }
+}
+
+/*
+** Return true if the iterator passed as the second argument currently
+** points to a delete marker. A delete marker is an entry with a 0 byte
+** position-list.
+*/
+static int fts5MultiIterIsEmpty(Fts5Index *p, Fts5Iter *pIter){
+  Fts5SegIter *pSeg = &pIter->aSeg[pIter->aFirst[1].iFirst];
+  return (p->rc==SQLITE_OK && pSeg->pLeaf && pSeg->nPos==0);
+}
+
+/*
+** Advance iterator pIter to the next entry.
+**
+** This version of fts5SegIterNext() is only used by reverse iterators.
+*/
+static void fts5SegIterNext_Reverse(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  int *pbUnused                   /* Unused */
+){
+  assert( pIter->flags & FTS5_SEGITER_REVERSE );
+  assert( pIter->pNextLeaf==0 );
+  UNUSED_PARAM(pbUnused);
+
+  if( pIter->iRowidOffset>0 ){
+    u8 *a = pIter->pLeaf->p;
+    int iOff;
+    u64 iDelta;
+
+    pIter->iRowidOffset--;
+    pIter->iLeafOffset = pIter->aRowidOffset[pIter->iRowidOffset];
+    fts5SegIterLoadNPos(p, pIter);
+    iOff = pIter->iLeafOffset;
+    if( p->pConfig->eDetail!=FTS5_DETAIL_NONE ){
+      iOff += pIter->nPos;
+    }
+    fts5GetVarint(&a[iOff], &iDelta);
+    pIter->iRowid -= iDelta;
+  }else{
+    fts5SegIterReverseNewPage(p, pIter);
+  }
+}
+
+/*
+** Advance iterator pIter to the next entry.
+**
+** This version of fts5SegIterNext() is only used if detail=none and the
+** iterator is not a reverse direction iterator.
+*/
+static void fts5SegIterNext_None(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  int *pbNewTerm                  /* OUT: Set for new term */
+){
+  int iOff;
+
+  assert( p->rc==SQLITE_OK );
+  assert( (pIter->flags & FTS5_SEGITER_REVERSE)==0 );
+  assert( p->pConfig->eDetail==FTS5_DETAIL_NONE );
+
+  ASSERT_SZLEAF_OK(pIter->pLeaf);
+  iOff = pIter->iLeafOffset;
+
+  /* Next entry is on the next page */
+  while( pIter->pSeg && iOff>=pIter->pLeaf->szLeaf ){
+    fts5SegIterNextPage(p, pIter);
+    if( p->rc || pIter->pLeaf==0 ) return;
+    pIter->iRowid = 0;
+    iOff = 4;
+  }
+
+  if( iOff<pIter->iEndofDoclist ){
+    /* Next entry is on the current page */
+    u64 iDelta;
+    iOff += sqlite3Fts5GetVarint(&pIter->pLeaf->p[iOff], (u64*)&iDelta);
+    pIter->iLeafOffset = iOff;
+    pIter->iRowid += iDelta;
+  }else if( (pIter->flags & FTS5_SEGITER_ONETERM)==0 ){
+    if( pIter->pSeg ){
+      int nKeep = 0;
+      if( iOff!=fts5LeafFirstTermOff(pIter->pLeaf) ){
+        iOff += fts5GetVarint32(&pIter->pLeaf->p[iOff], nKeep);
+      }
+      pIter->iLeafOffset = iOff;
+      fts5SegIterLoadTerm(p, pIter, nKeep);
+    }else{
+      const u8 *pList = 0;
+      const char *zTerm = 0;
+      int nTerm = 0;
+      int nList;
+      sqlite3Fts5HashScanNext(p->pHash);
+      sqlite3Fts5HashScanEntry(p->pHash, &zTerm, &nTerm, &pList, &nList);
+      if( pList==0 ) goto next_none_eof;
+      pIter->pLeaf->p = (u8*)pList;
+      pIter->pLeaf->nn = nList;
+      pIter->pLeaf->szLeaf = nList;
+      pIter->iEndofDoclist = nList;
+      sqlite3Fts5BufferSet(&p->rc,&pIter->term, nTerm, (u8*)zTerm);
+      pIter->iLeafOffset = fts5GetVarint(pList, (u64*)&pIter->iRowid);
+    }
+
+    if( pbNewTerm ) *pbNewTerm = 1;
+  }else{
+    goto next_none_eof;
+  }
+
+  fts5SegIterLoadNPos(p, pIter);
+
+  return;
+ next_none_eof:
+  fts5DataRelease(pIter->pLeaf);
+  pIter->pLeaf = 0;
+}
+
+
+/*
+** Advance iterator pIter to the next entry.
+**
+** If an error occurs, Fts5Index.rc is set to an appropriate error code. It
+** is not considered an error if the iterator reaches EOF. If an error has
+** already occurred when this function is called, it is a no-op.
+*/
+static void fts5SegIterNext(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  int *pbNewTerm                  /* OUT: Set for new term */
+){
+  Fts5Data *pLeaf = pIter->pLeaf;
+  int iOff;
+  int bNewTerm = 0;
+  int nKeep = 0;
+  u8 *a;
+  int n;
+
+  assert( pbNewTerm==0 || *pbNewTerm==0 );
+  assert( p->pConfig->eDetail!=FTS5_DETAIL_NONE );
+
+  /* Search for the end of the position list within the current page. */
+  a = pLeaf->p;
+  n = pLeaf->szLeaf;
+
+  ASSERT_SZLEAF_OK(pLeaf);
+  iOff = pIter->iLeafOffset + pIter->nPos;
+
+  if( iOff<n ){
+    /* The next entry is on the current page. */
+    assert_nc( iOff<=pIter->iEndofDoclist );
+    if( iOff>=pIter->iEndofDoclist ){
+      bNewTerm = 1;
+      if( iOff!=fts5LeafFirstTermOff(pLeaf) ){
+        iOff += fts5GetVarint32(&a[iOff], nKeep);
+      }
+    }else{
+      u64 iDelta;
+      iOff += sqlite3Fts5GetVarint(&a[iOff], &iDelta);
+      pIter->iRowid += iDelta;
+      assert_nc( iDelta>0 );
+    }
+    pIter->iLeafOffset = iOff;
+
+  }else if( pIter->pSeg==0 ){
+    const u8 *pList = 0;
+    const char *zTerm = 0;
+    int nTerm = 0;
+    int nList = 0;
+    assert( (pIter->flags & FTS5_SEGITER_ONETERM) || pbNewTerm );
+    if( 0==(pIter->flags & FTS5_SEGITER_ONETERM) ){
+      sqlite3Fts5HashScanNext(p->pHash);
+      sqlite3Fts5HashScanEntry(p->pHash, &zTerm, &nTerm, &pList, &nList);
+    }
+    if( pList==0 ){
+      fts5DataRelease(pIter->pLeaf);
+      pIter->pLeaf = 0;
+    }else{
+      pIter->pLeaf->p = (u8*)pList;
+      pIter->pLeaf->nn = nList;
+      pIter->pLeaf->szLeaf = nList;
+      pIter->iEndofDoclist = nList+1;
+      sqlite3Fts5BufferSet(&p->rc, &pIter->term, nTerm, (u8*)zTerm);
+      pIter->iLeafOffset = fts5GetVarint(pList, (u64*)&pIter->iRowid);
+      *pbNewTerm = 1;
+    }
+  }else{
+    iOff = 0;
+    /* Next entry is not on the current page */
+    while( iOff==0 ){
+      fts5SegIterNextPage(p, pIter);
+      pLeaf = pIter->pLeaf;
+      if( pLeaf==0 ) break;
+      ASSERT_SZLEAF_OK(pLeaf);
+      if( (iOff = fts5LeafFirstRowidOff(pLeaf)) && iOff<pLeaf->szLeaf ){
+        iOff += sqlite3Fts5GetVarint(&pLeaf->p[iOff], (u64*)&pIter->iRowid);
+        pIter->iLeafOffset = iOff;
+
+        if( pLeaf->nn>pLeaf->szLeaf ){
+          pIter->iPgidxOff = pLeaf->szLeaf + fts5GetVarint32(
+              &pLeaf->p[pLeaf->szLeaf], pIter->iEndofDoclist
+          );
+        }
+      }
+      else if( pLeaf->nn>pLeaf->szLeaf ){
+        pIter->iPgidxOff = pLeaf->szLeaf + fts5GetVarint32(
+            &pLeaf->p[pLeaf->szLeaf], iOff
+        );
+        pIter->iLeafOffset = iOff;
+        pIter->iEndofDoclist = iOff;
+        bNewTerm = 1;
+      }
+      assert_nc( iOff<pLeaf->szLeaf );
+      if( iOff>pLeaf->szLeaf ){
+        p->rc = FTS5_CORRUPT;
+        return;
+      }
+    }
+  }
+
+  /* Check if the iterator is now at EOF. If so, return early. */
+  if( pIter->pLeaf ){
+    if( bNewTerm ){
+      if( pIter->flags & FTS5_SEGITER_ONETERM ){
+        fts5DataRelease(pIter->pLeaf);
+        pIter->pLeaf = 0;
+      }else{
+        fts5SegIterLoadTerm(p, pIter, nKeep);
+        fts5SegIterLoadNPos(p, pIter);
+        if( pbNewTerm ) *pbNewTerm = 1;
+      }
+    }else{
+      /* The following could be done by calling fts5SegIterLoadNPos(). But
+      ** this block is particularly performance critical, so equivalent
+      ** code is inlined.  */
+      int nSz;
+      assert_nc( pIter->iLeafOffset<=pIter->pLeaf->nn );
+      fts5FastGetVarint32(pIter->pLeaf->p, pIter->iLeafOffset, nSz);
+      pIter->bDel = (nSz & 0x0001);
+      pIter->nPos = nSz>>1;
+      assert_nc( pIter->nPos>=0 );
+    }
+  }
+}
+
+#define SWAPVAL(T, a, b) { T tmp; tmp=a; a=b; b=tmp; }
+
+#define fts5IndexSkipVarint(a, iOff) {            \
+  int iEnd = iOff+9;                              \
+  while( (a[iOff++] & 0x80) && iOff<iEnd );       \
+}
+
+/*
+** Iterator pIter currently points to the first rowid in a doclist. This
+** function sets the iterator up so that iterates in reverse order through
+** the doclist.
+*/
+static void fts5SegIterReverse(Fts5Index *p, Fts5SegIter *pIter){
+  Fts5DlidxIter *pDlidx = pIter->pDlidx;
+  Fts5Data *pLast = 0;
+  int pgnoLast = 0;
+
+  if( pDlidx && p->pConfig->iVersion==FTS5_CURRENT_VERSION ){
+    int iSegid = pIter->pSeg->iSegid;
+    pgnoLast = fts5DlidxIterPgno(pDlidx);
+    pLast = fts5LeafRead(p, FTS5_SEGMENT_ROWID(iSegid, pgnoLast));
+  }else{
+    Fts5Data *pLeaf = pIter->pLeaf;         /* Current leaf data */
+
+    /* Currently, Fts5SegIter.iLeafOffset points to the first byte of
+    ** position-list content for the current rowid. Back it up so that it
+    ** points to the start of the position-list size field. */
+    int iPoslist;
+    if( pIter->iTermLeafPgno==pIter->iLeafPgno ){
+      iPoslist = pIter->iTermLeafOffset;
+    }else{
+      iPoslist = 4;
+    }
+    fts5IndexSkipVarint(pLeaf->p, iPoslist);
+    pIter->iLeafOffset = iPoslist;
+
+    /* If this condition is true then the largest rowid for the current
+    ** term may not be stored on the current page. So search forward to
+    ** see where said rowid really is.  */
+    if( pIter->iEndofDoclist>=pLeaf->szLeaf ){
+      int pgno;
+      Fts5StructureSegment *pSeg = pIter->pSeg;
+
+      /* The last rowid in the doclist may not be on the current page. Search
+      ** forward to find the page containing the last rowid.  */
+      for(pgno=pIter->iLeafPgno+1; !p->rc && pgno<=pSeg->pgnoLast; pgno++){
+        i64 iAbs = FTS5_SEGMENT_ROWID(pSeg->iSegid, pgno);
+        Fts5Data *pNew = fts5LeafRead(p, iAbs);
+        if( pNew ){
+          int iRowid, bTermless;
+          iRowid = fts5LeafFirstRowidOff(pNew);
+          bTermless = fts5LeafIsTermless(pNew);
+          if( iRowid ){
+            SWAPVAL(Fts5Data*, pNew, pLast);
+            pgnoLast = pgno;
+          }
+          fts5DataRelease(pNew);
+          if( bTermless==0 ) break;
+        }
+      }
+    }
+  }
+
+  /* If pLast is NULL at this point, then the last rowid for this doclist
+  ** lies on the page currently indicated by the iterator. In this case
+  ** pIter->iLeafOffset is already set to point to the position-list size
+  ** field associated with the first relevant rowid on the page.
+  **
+  ** Or, if pLast is non-NULL, then it is the page that contains the last
+  ** rowid. In this case configure the iterator so that it points to the
+  ** first rowid on this page.
+  */
+  if( pLast ){
+    int iOff;
+    fts5DataRelease(pIter->pLeaf);
+    pIter->pLeaf = pLast;
+    pIter->iLeafPgno = pgnoLast;
+    iOff = fts5LeafFirstRowidOff(pLast);
+    if( iOff>pLast->szLeaf ){
+      p->rc = FTS5_CORRUPT;
+      return;
+    }
+    iOff += fts5GetVarint(&pLast->p[iOff], (u64*)&pIter->iRowid);
+    pIter->iLeafOffset = iOff;
+
+    if( fts5LeafIsTermless(pLast) ){
+      pIter->iEndofDoclist = pLast->nn+1;
+    }else{
+      pIter->iEndofDoclist = fts5LeafFirstTermOff(pLast);
+    }
+  }
+
+  fts5SegIterReverseInitPage(p, pIter);
+}
+
+/*
+** Iterator pIter currently points to the first rowid of a doclist.
+** There is a doclist-index associated with the final term on the current
+** page. If the current term is the last term on the page, load the
+** doclist-index from disk and initialize an iterator at (pIter->pDlidx).
+*/
+static void fts5SegIterLoadDlidx(Fts5Index *p, Fts5SegIter *pIter){
+  int iSeg = pIter->pSeg->iSegid;
+  int bRev = (pIter->flags & FTS5_SEGITER_REVERSE);
+  Fts5Data *pLeaf = pIter->pLeaf; /* Current leaf data */
+
+  assert( pIter->flags & FTS5_SEGITER_ONETERM );
+  assert( pIter->pDlidx==0 );
+
+  /* Check if the current doclist ends on this page. If it does, return
+  ** early without loading the doclist-index (as it belongs to a different
+  ** term. */
+  if( pIter->iTermLeafPgno==pIter->iLeafPgno
+   && pIter->iEndofDoclist<pLeaf->szLeaf
+  ){
+    return;
+  }
+
+  pIter->pDlidx = fts5DlidxIterInit(p, bRev, iSeg, pIter->iTermLeafPgno);
+}
+
+/*
+** The iterator object passed as the second argument currently contains
+** no valid values except for the Fts5SegIter.pLeaf member variable. This
+** function searches the leaf page for a term matching (pTerm/nTerm).
+**
+** If the specified term is found on the page, then the iterator is left
+** pointing to it. If argument bGe is zero and the term is not found,
+** the iterator is left pointing at EOF.
+**
+** If bGe is non-zero and the specified term is not found, then the
+** iterator is left pointing to the smallest term in the segment that
+** is larger than the specified term, even if this term is not on the
+** current page.
+*/
+static void fts5LeafSeek(
+  Fts5Index *p,                   /* Leave any error code here */
+  int bGe,                        /* True for a >= search */
+  Fts5SegIter *pIter,             /* Iterator to seek */
+  const u8 *pTerm, int nTerm      /* Term to search for */
+){
+  u32 iOff;
+  const u8 *a = pIter->pLeaf->p;
+  u32 n = (u32)pIter->pLeaf->nn;
+
+  u32 nMatch = 0;
+  u32 nKeep = 0;
+  u32 nNew = 0;
+  u32 iTermOff;
+  u32 iPgidx;                     /* Current offset in pgidx */
+  int bEndOfPage = 0;
+
+  assert( p->rc==SQLITE_OK );
+
+  iPgidx = (u32)pIter->pLeaf->szLeaf;
+  iPgidx += fts5GetVarint32(&a[iPgidx], iTermOff);
+  iOff = iTermOff;
+  if( iOff>n ){
+    p->rc = FTS5_CORRUPT;
+    return;
+  }
+
+  while( 1 ){
+
+    /* Figure out how many new bytes are in this term */
+    fts5FastGetVarint32(a, iOff, nNew);
+    if( nKeep<nMatch ){
+      goto search_failed;
+    }
+
+    assert( nKeep>=nMatch );
+    if( nKeep==nMatch ){
+      u32 nCmp;
+      u32 i;
+      nCmp = (u32)MIN(nNew, nTerm-nMatch);
+      for(i=0; i<nCmp; i++){
+        if( a[iOff+i]!=pTerm[nMatch+i] ) break;
+      }
+      nMatch += i;
+
+      if( (u32)nTerm==nMatch ){
+        if( i==nNew ){
+          goto search_success;
+        }else{
+          goto search_failed;
+        }
+      }else if( i<nNew && a[iOff+i]>pTerm[nMatch] ){
+        goto search_failed;
+      }
+    }
+
+    if( iPgidx>=n ){
+      bEndOfPage = 1;
+      break;
+    }
+
+    iPgidx += fts5GetVarint32(&a[iPgidx], nKeep);
+    iTermOff += nKeep;
+    iOff = iTermOff;
+
+    if( iOff>=n ){
+      p->rc = FTS5_CORRUPT;
+      return;
+    }
+
+    /* Read the nKeep field of the next term. */
+    fts5FastGetVarint32(a, iOff, nKeep);
+  }
+
+ search_failed:
+  if( bGe==0 ){
+    fts5DataRelease(pIter->pLeaf);
+    pIter->pLeaf = 0;
+    return;
+  }else if( bEndOfPage ){
+    do {
+      fts5SegIterNextPage(p, pIter);
+      if( pIter->pLeaf==0 ) return;
+      a = pIter->pLeaf->p;
+      if( fts5LeafIsTermless(pIter->pLeaf)==0 ){
+        iPgidx = (u32)pIter->pLeaf->szLeaf;
+        iPgidx += fts5GetVarint32(&pIter->pLeaf->p[iPgidx], iOff);
+        if( iOff<4 || (i64)iOff>=pIter->pLeaf->szLeaf ){
+          p->rc = FTS5_CORRUPT;
+          return;
+        }else{
+          nKeep = 0;
+          iTermOff = iOff;
+          n = (u32)pIter->pLeaf->nn;
+          iOff += fts5GetVarint32(&a[iOff], nNew);
+          break;
+        }
+      }
+    }while( 1 );
+  }
+
+ search_success:
+  if( (i64)iOff+nNew>n || nNew<1 ){
+    p->rc = FTS5_CORRUPT;
+    return;
+  }
+  pIter->iLeafOffset = iOff + nNew;
+  pIter->iTermLeafOffset = pIter->iLeafOffset;
+  pIter->iTermLeafPgno = pIter->iLeafPgno;
+
+  fts5BufferSet(&p->rc, &pIter->term, nKeep, pTerm);
+  fts5BufferAppendBlob(&p->rc, &pIter->term, nNew, &a[iOff]);
+
+  if( iPgidx>=n ){
+    pIter->iEndofDoclist = pIter->pLeaf->nn+1;
+  }else{
+    int nExtra;
+    iPgidx += fts5GetVarint32(&a[iPgidx], nExtra);
+    pIter->iEndofDoclist = iTermOff + nExtra;
+  }
+  pIter->iPgidxOff = iPgidx;
+
+  fts5SegIterLoadRowid(p, pIter);
+  fts5SegIterLoadNPos(p, pIter);
+}
+
+static sqlite3_stmt *fts5IdxSelectStmt(Fts5Index *p){
+  if( p->pIdxSelect==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pIdxSelect, sqlite3_mprintf(
+          "SELECT pgno FROM '%q'.'%q_idx' WHERE "
+          "segid=? AND term<=? ORDER BY term DESC LIMIT 1",
+          pConfig->zDb, pConfig->zName
+    ));
+  }
+  return p->pIdxSelect;
+}
+
+/*
+** Initialize the object pIter to point to term pTerm/nTerm within segment
+** pSeg. If there is no such term in the index, the iterator is set to EOF.
+**
+** If an error occurs, Fts5Index.rc is set to an appropriate error code. If
+** an error has already occurred when this function is called, it is a no-op.
+*/
+static void fts5SegIterSeekInit(
+  Fts5Index *p,                   /* FTS5 backend */
+  const u8 *pTerm, int nTerm,     /* Term to seek to */
+  int flags,                      /* Mask of FTS5INDEX_XXX flags */
+  Fts5StructureSegment *pSeg,     /* Description of segment */
+  Fts5SegIter *pIter              /* Object to populate */
+){
+  int iPg = 1;
+  int bGe = (flags & FTS5INDEX_QUERY_SCAN);
+  int bDlidx = 0;                 /* True if there is a doclist-index */
+  sqlite3_stmt *pIdxSelect = 0;
+
+  assert( bGe==0 || (flags & FTS5INDEX_QUERY_DESC)==0 );
+  assert( pTerm && nTerm );
+  memset(pIter, 0, sizeof(*pIter));
+  pIter->pSeg = pSeg;
+
+  /* This block sets stack variable iPg to the leaf page number that may
+  ** contain term (pTerm/nTerm), if it is present in the segment. */
+  pIdxSelect = fts5IdxSelectStmt(p);
+  if( p->rc ) return;
+  sqlite3_bind_int(pIdxSelect, 1, pSeg->iSegid);
+  sqlite3_bind_blob(pIdxSelect, 2, pTerm, nTerm, SQLITE_STATIC);
+  if( SQLITE_ROW==sqlite3_step(pIdxSelect) ){
+    i64 val = sqlite3_column_int(pIdxSelect, 0);
+    iPg = (int)(val>>1);
+    bDlidx = (val & 0x0001);
+  }
+  p->rc = sqlite3_reset(pIdxSelect);
+  sqlite3_bind_null(pIdxSelect, 2);
+
+  if( iPg<pSeg->pgnoFirst ){
+    iPg = pSeg->pgnoFirst;
+    bDlidx = 0;
+  }
+
+  pIter->iLeafPgno = iPg - 1;
+  fts5SegIterNextPage(p, pIter);
+
+  if( pIter->pLeaf ){
+    fts5LeafSeek(p, bGe, pIter, pTerm, nTerm);
+  }
+
+  if( p->rc==SQLITE_OK && (bGe==0 || (flags & FTS5INDEX_QUERY_SCANONETERM)) ){
+    pIter->flags |= FTS5_SEGITER_ONETERM;
+    if( pIter->pLeaf ){
+      if( flags & FTS5INDEX_QUERY_DESC ){
+        pIter->flags |= FTS5_SEGITER_REVERSE;
+      }
+      if( bDlidx ){
+        fts5SegIterLoadDlidx(p, pIter);
+      }
+      if( flags & FTS5INDEX_QUERY_DESC ){
+        fts5SegIterReverse(p, pIter);
+      }
+    }
+  }
+
+  fts5SegIterSetNext(p, pIter);
+  if( 0==(flags & FTS5INDEX_QUERY_SCANONETERM) ){
+    fts5SegIterAllocTombstone(p, pIter);
+  }
+
+  /* Either:
+  **
+  **   1) an error has occurred, or
+  **   2) the iterator points to EOF, or
+  **   3) the iterator points to an entry with term (pTerm/nTerm), or
+  **   4) the FTS5INDEX_QUERY_SCAN flag was set and the iterator points
+  **      to an entry with a term greater than or equal to (pTerm/nTerm).
+  */
+  assert_nc( p->rc!=SQLITE_OK                                       /* 1 */
+   || pIter->pLeaf==0                                               /* 2 */
+   || fts5BufferCompareBlob(&pIter->term, pTerm, nTerm)==0          /* 3 */
+   || (bGe && fts5BufferCompareBlob(&pIter->term, pTerm, nTerm)>0)  /* 4 */
+  );
+}
+
+
+/*
+** SQL used by fts5SegIterNextInit() to find the page to open.
+*/
+static sqlite3_stmt *fts5IdxNextStmt(Fts5Index *p){
+  if( p->pIdxNextSelect==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pIdxNextSelect, sqlite3_mprintf(
+          "SELECT pgno FROM '%q'.'%q_idx' WHERE "
+          "segid=? AND term>? ORDER BY term ASC LIMIT 1",
+          pConfig->zDb, pConfig->zName
+    ));
+
+  }
+  return p->pIdxNextSelect;
+}
+
+/*
+** This is similar to fts5SegIterSeekInit(), except that it initializes
+** the segment iterator to point to the first term following the page
+** with pToken/nToken on it.
+*/
+static void fts5SegIterNextInit(
+  Fts5Index *p,
+  const char *pTerm, int nTerm,
+  Fts5StructureSegment *pSeg,     /* Description of segment */
+  Fts5SegIter *pIter              /* Object to populate */
+){
+  int iPg = -1;                   /* Page of segment to open */
+  int bDlidx = 0;
+  sqlite3_stmt *pSel = 0;         /* SELECT to find iPg */
+
+  pSel = fts5IdxNextStmt(p);
+  if( pSel ){
+    assert( p->rc==SQLITE_OK );
+    sqlite3_bind_int(pSel, 1, pSeg->iSegid);
+    sqlite3_bind_blob(pSel, 2, pTerm, nTerm, SQLITE_STATIC);
+
+    if( sqlite3_step(pSel)==SQLITE_ROW ){
+      i64 val = sqlite3_column_int64(pSel, 0);
+      iPg = (int)(val>>1);
+      bDlidx = (val & 0x0001);
+    }
+    p->rc = sqlite3_reset(pSel);
+    sqlite3_bind_null(pSel, 2);
+    if( p->rc ) return;
+  }
+
+  memset(pIter, 0, sizeof(*pIter));
+  pIter->pSeg = pSeg;
+  pIter->flags |= FTS5_SEGITER_ONETERM;
+  if( iPg>=0 ){
+    pIter->iLeafPgno = iPg - 1;
+    fts5SegIterNextPage(p, pIter);
+    fts5SegIterSetNext(p, pIter);
+  }
+  if( pIter->pLeaf ){
+    const u8 *a = pIter->pLeaf->p;
+    int iTermOff = 0;
+
+    pIter->iPgidxOff = pIter->pLeaf->szLeaf;
+    pIter->iPgidxOff += fts5GetVarint32(&a[pIter->iPgidxOff], iTermOff);
+    pIter->iLeafOffset = iTermOff;
+    fts5SegIterLoadTerm(p, pIter, 0);
+    fts5SegIterLoadNPos(p, pIter);
+    if( bDlidx ) fts5SegIterLoadDlidx(p, pIter);
+
+    assert( p->rc!=SQLITE_OK ||
+        fts5BufferCompareBlob(&pIter->term, (const u8*)pTerm, nTerm)>0
+    );
+  }
+}
+
+/*
+** Initialize the object pIter to point to term pTerm/nTerm within the
+** in-memory hash table. If there is no such term in the hash-table, the
+** iterator is set to EOF.
+**
+** If an error occurs, Fts5Index.rc is set to an appropriate error code. If
+** an error has already occurred when this function is called, it is a no-op.
+*/
+static void fts5SegIterHashInit(
+  Fts5Index *p,                   /* FTS5 backend */
+  const u8 *pTerm, int nTerm,     /* Term to seek to */
+  int flags,                      /* Mask of FTS5INDEX_XXX flags */
+  Fts5SegIter *pIter              /* Object to populate */
+){
+  int nList = 0;
+  const u8 *z = 0;
+  int n = 0;
+  Fts5Data *pLeaf = 0;
+
+  assert( p->pHash );
+  assert( p->rc==SQLITE_OK );
+
+  if( pTerm==0 || (flags & FTS5INDEX_QUERY_SCAN) ){
+    const u8 *pList = 0;
+
+    p->rc = sqlite3Fts5HashScanInit(p->pHash, (const char*)pTerm, nTerm);
+    sqlite3Fts5HashScanEntry(p->pHash, (const char**)&z, &n, &pList, &nList);
+    if( pList ){
+      pLeaf = fts5IdxMalloc(p, sizeof(Fts5Data));
+      if( pLeaf ){
+        pLeaf->p = (u8*)pList;
+      }
+    }
+
+    /* The call to sqlite3Fts5HashScanInit() causes the hash table to
+    ** fill the size field of all existing position lists. This means they
+    ** can no longer be appended to. Since the only scenario in which they
+    ** can be appended to is if the previous operation on this table was
+    ** a DELETE, by clearing the Fts5Index.bDelete flag we can avoid this
+    ** possibility altogether.  */
+    p->bDelete = 0;
+  }else{
+    p->rc = sqlite3Fts5HashQuery(p->pHash, sizeof(Fts5Data),
+        (const char*)pTerm, nTerm, (void**)&pLeaf, &nList
+    );
+    if( pLeaf ){
+      pLeaf->p = (u8*)&pLeaf[1];
+    }
+    z = pTerm;
+    n = nTerm;
+    pIter->flags |= FTS5_SEGITER_ONETERM;
+  }
+
+  if( pLeaf ){
+    sqlite3Fts5BufferSet(&p->rc, &pIter->term, n, z);
+    pLeaf->nn = pLeaf->szLeaf = nList;
+    pIter->pLeaf = pLeaf;
+    pIter->iLeafOffset = fts5GetVarint(pLeaf->p, (u64*)&pIter->iRowid);
+    pIter->iEndofDoclist = pLeaf->nn;
+
+    if( flags & FTS5INDEX_QUERY_DESC ){
+      pIter->flags |= FTS5_SEGITER_REVERSE;
+      fts5SegIterReverseInitPage(p, pIter);
+    }else{
+      fts5SegIterLoadNPos(p, pIter);
+    }
+  }
+
+  fts5SegIterSetNext(p, pIter);
+}
+
+/*
+** Array ap[] contains n elements. Release each of these elements using
+** fts5DataRelease(). Then free the array itself using sqlite3_free().
+*/
+static void fts5IndexFreeArray(Fts5Data **ap, int n){
+  if( ap ){
+    int ii;
+    for(ii=0; ii<n; ii++){
+      fts5DataRelease(ap[ii]);
+    }
+    sqlite3_free(ap);
+  }
+}
+
+/*
+** Decrement the ref-count of the object passed as the only argument. If it
+** reaches 0, free it and its contents.
+*/
+static void fts5TombstoneArrayDelete(Fts5TombstoneArray *p){
+  if( p ){
+    p->nRef--;
+    if( p->nRef<=0 ){
+      int ii;
+      for(ii=0; ii<p->nTombstone; ii++){
+        fts5DataRelease(p->apTombstone[ii]);
+      }
+      sqlite3_free(p);
+    }
+  }
+}
+
+/*
+** Zero the iterator passed as the only argument.
+*/
+static void fts5SegIterClear(Fts5SegIter *pIter){
+  fts5BufferFree(&pIter->term);
+  fts5DataRelease(pIter->pLeaf);
+  fts5DataRelease(pIter->pNextLeaf);
+  fts5TombstoneArrayDelete(pIter->pTombArray);
+  fts5DlidxIterFree(pIter->pDlidx);
+  sqlite3_free(pIter->aRowidOffset);
+  memset(pIter, 0, sizeof(Fts5SegIter));
+}
+
+#ifdef SQLITE_DEBUG
+
+/*
+** This function is used as part of the big assert() procedure implemented by
+** fts5AssertMultiIterSetup(). It ensures that the result currently stored
+** in *pRes is the correct result of comparing the current positions of the
+** two iterators.
+*/
+static void fts5AssertComparisonResult(
+  Fts5Iter *pIter,
+  Fts5SegIter *p1,
+  Fts5SegIter *p2,
+  Fts5CResult *pRes
+){
+  int i1 = p1 - pIter->aSeg;
+  int i2 = p2 - pIter->aSeg;
+
+  if( p1->pLeaf || p2->pLeaf ){
+    if( p1->pLeaf==0 ){
+      assert( pRes->iFirst==i2 );
+    }else if( p2->pLeaf==0 ){
+      assert( pRes->iFirst==i1 );
+    }else{
+      int nMin = MIN(p1->term.n, p2->term.n);
+      int res = fts5Memcmp(p1->term.p, p2->term.p, nMin);
+      if( res==0 ) res = p1->term.n - p2->term.n;
+
+      if( res==0 ){
+        assert( pRes->bTermEq==1 );
+        assert( p1->iRowid!=p2->iRowid );
+        res = ((p1->iRowid > p2->iRowid)==pIter->bRev) ? -1 : 1;
+      }else{
+        assert( pRes->bTermEq==0 );
+      }
+
+      if( res<0 ){
+        assert( pRes->iFirst==i1 );
+      }else{
+        assert( pRes->iFirst==i2 );
+      }
+    }
+  }
+}
+
+/*
+** This function is a no-op unless SQLITE_DEBUG is defined when this module
+** is compiled. In that case, this function is essentially an assert()
+** statement used to verify that the contents of the pIter->aFirst[] array
+** are correct.
+*/
+static void fts5AssertMultiIterSetup(Fts5Index *p, Fts5Iter *pIter){
+  if( p->rc==SQLITE_OK ){
+    Fts5SegIter *pFirst = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+    int i;
+
+    assert( (pFirst->pLeaf==0)==pIter->base.bEof );
+
+    /* Check that pIter->iSwitchRowid is set correctly. */
+    for(i=0; i<pIter->nSeg; i++){
+      Fts5SegIter *p1 = &pIter->aSeg[i];
+      assert( p1==pFirst
+           || p1->pLeaf==0
+           || fts5BufferCompare(&pFirst->term, &p1->term)
+           || p1->iRowid==pIter->iSwitchRowid
+           || (p1->iRowid<pIter->iSwitchRowid)==pIter->bRev
+      );
+    }
+
+    for(i=0; i<pIter->nSeg; i+=2){
+      Fts5SegIter *p1 = &pIter->aSeg[i];
+      Fts5SegIter *p2 = &pIter->aSeg[i+1];
+      Fts5CResult *pRes = &pIter->aFirst[(pIter->nSeg + i) / 2];
+      fts5AssertComparisonResult(pIter, p1, p2, pRes);
+    }
+
+    for(i=1; i<(pIter->nSeg / 2); i+=2){
+      Fts5SegIter *p1 = &pIter->aSeg[ pIter->aFirst[i*2].iFirst ];
+      Fts5SegIter *p2 = &pIter->aSeg[ pIter->aFirst[i*2+1].iFirst ];
+      Fts5CResult *pRes = &pIter->aFirst[i];
+      fts5AssertComparisonResult(pIter, p1, p2, pRes);
+    }
+  }
+}
+#else
+# define fts5AssertMultiIterSetup(x,y)
+#endif
+
+/*
+** Do the comparison necessary to populate pIter->aFirst[iOut].
+**
+** If the returned value is non-zero, then it is the index of an entry
+** in the pIter->aSeg[] array that is (a) not at EOF, and (b) pointing
+** to a key that is a duplicate of another, higher priority,
+** segment-iterator in the pSeg->aSeg[] array.
+*/
+static int fts5MultiIterDoCompare(Fts5Iter *pIter, int iOut){
+  int i1;                         /* Index of left-hand Fts5SegIter */
+  int i2;                         /* Index of right-hand Fts5SegIter */
+  int iRes;
+  Fts5SegIter *p1;                /* Left-hand Fts5SegIter */
+  Fts5SegIter *p2;                /* Right-hand Fts5SegIter */
+  Fts5CResult *pRes = &pIter->aFirst[iOut];
+
+  assert( iOut<pIter->nSeg && iOut>0 );
+  assert( pIter->bRev==0 || pIter->bRev==1 );
+
+  if( iOut>=(pIter->nSeg/2) ){
+    i1 = (iOut - pIter->nSeg/2) * 2;
+    i2 = i1 + 1;
+  }else{
+    i1 = pIter->aFirst[iOut*2].iFirst;
+    i2 = pIter->aFirst[iOut*2+1].iFirst;
+  }
+  p1 = &pIter->aSeg[i1];
+  p2 = &pIter->aSeg[i2];
+
+  pRes->bTermEq = 0;
+  if( p1->pLeaf==0 ){           /* If p1 is at EOF */
+    iRes = i2;
+  }else if( p2->pLeaf==0 ){     /* If p2 is at EOF */
+    iRes = i1;
+  }else{
+    int res = fts5BufferCompare(&p1->term, &p2->term);
+    if( res==0 ){
+      assert_nc( i2>i1 );
+      assert_nc( i2!=0 );
+      pRes->bTermEq = 1;
+      if( p1->iRowid==p2->iRowid ){
+        return i2;
+      }
+      res = ((p1->iRowid > p2->iRowid)==pIter->bRev) ? -1 : +1;
+    }
+    assert( res!=0 );
+    if( res<0 ){
+      iRes = i1;
+    }else{
+      iRes = i2;
+    }
+  }
+
+  pRes->iFirst = (u16)iRes;
+  return 0;
+}
+
+/*
+** Move the seg-iter so that it points to the first rowid on page iLeafPgno.
+** It is an error if leaf iLeafPgno does not exist. Unless the db is
+** a 'secure-delete' db, if it contains no rowids then this is also an error.
+*/
+static void fts5SegIterGotoPage(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  int iLeafPgno
+){
+  assert( iLeafPgno>pIter->iLeafPgno );
+
+  if( iLeafPgno>pIter->pSeg->pgnoLast ){
+    p->rc = FTS5_CORRUPT;
+  }else{
+    fts5DataRelease(pIter->pNextLeaf);
+    pIter->pNextLeaf = 0;
+    pIter->iLeafPgno = iLeafPgno-1;
+
+    while( p->rc==SQLITE_OK ){
+      int iOff;
+      fts5SegIterNextPage(p, pIter);
+      if( pIter->pLeaf==0 ) break;
+      iOff = fts5LeafFirstRowidOff(pIter->pLeaf);
+      if( iOff>0 ){
+        u8 *a = pIter->pLeaf->p;
+        int n = pIter->pLeaf->szLeaf;
+        if( iOff<4 || iOff>=n ){
+          p->rc = FTS5_CORRUPT;
+        }else{
+          iOff += fts5GetVarint(&a[iOff], (u64*)&pIter->iRowid);
+          pIter->iLeafOffset = iOff;
+          fts5SegIterLoadNPos(p, pIter);
+        }
+        break;
+      }
+    }
+  }
+}
+
+/*
+** Advance the iterator passed as the second argument until it is at or
+** past rowid iFrom. Regardless of the value of iFrom, the iterator is
+** always advanced at least once.
+*/
+static void fts5SegIterNextFrom(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegIter *pIter,             /* Iterator to advance */
+  i64 iMatch                      /* Advance iterator at least this far */
+){
+  int bRev = (pIter->flags & FTS5_SEGITER_REVERSE);
+  Fts5DlidxIter *pDlidx = pIter->pDlidx;
+  int iLeafPgno = pIter->iLeafPgno;
+  int bMove = 1;
+
+  assert( pIter->flags & FTS5_SEGITER_ONETERM );
+  assert( pIter->pDlidx );
+  assert( pIter->pLeaf );
+
+  if( bRev==0 ){
+    while( !fts5DlidxIterEof(p, pDlidx) && iMatch>fts5DlidxIterRowid(pDlidx) ){
+      iLeafPgno = fts5DlidxIterPgno(pDlidx);
+      fts5DlidxIterNext(p, pDlidx);
+    }
+    assert_nc( iLeafPgno>=pIter->iLeafPgno || p->rc );
+    if( iLeafPgno>pIter->iLeafPgno ){
+      fts5SegIterGotoPage(p, pIter, iLeafPgno);
+      bMove = 0;
+    }
+  }else{
+    assert( pIter->pNextLeaf==0 );
+    assert( iMatch<pIter->iRowid );
+    while( !fts5DlidxIterEof(p, pDlidx) && iMatch<fts5DlidxIterRowid(pDlidx) ){
+      fts5DlidxIterPrev(p, pDlidx);
+    }
+    iLeafPgno = fts5DlidxIterPgno(pDlidx);
+
+    assert( fts5DlidxIterEof(p, pDlidx) || iLeafPgno<=pIter->iLeafPgno );
+
+    if( iLeafPgno<pIter->iLeafPgno ){
+      pIter->iLeafPgno = iLeafPgno+1;
+      fts5SegIterReverseNewPage(p, pIter);
+      bMove = 0;
+    }
+  }
+
+  do{
+    if( bMove && p->rc==SQLITE_OK ) pIter->xNext(p, pIter, 0);
+    if( pIter->pLeaf==0 ) break;
+    if( bRev==0 && pIter->iRowid>=iMatch ) break;
+    if( bRev!=0 && pIter->iRowid<=iMatch ) break;
+    bMove = 1;
+  }while( p->rc==SQLITE_OK );
+}
+
+/*
+** Free the iterator object passed as the second argument.
+*/
+static void fts5MultiIterFree(Fts5Iter *pIter){
+  if( pIter ){
+    int i;
+    for(i=0; i<pIter->nSeg; i++){
+      fts5SegIterClear(&pIter->aSeg[i]);
+    }
+    fts5BufferFree(&pIter->poslist);
+    sqlite3_free(pIter);
+  }
+}
+
+static void fts5MultiIterAdvanced(
+  Fts5Index *p,                   /* FTS5 backend to iterate within */
+  Fts5Iter *pIter,                /* Iterator to update aFirst[] array for */
+  int iChanged,                   /* Index of sub-iterator just advanced */
+  int iMinset                     /* Minimum entry in aFirst[] to set */
+){
+  int i;
+  for(i=(pIter->nSeg+iChanged)/2; i>=iMinset && p->rc==SQLITE_OK; i=i/2){
+    int iEq;
+    if( (iEq = fts5MultiIterDoCompare(pIter, i)) ){
+      Fts5SegIter *pSeg = &pIter->aSeg[iEq];
+      assert( p->rc==SQLITE_OK );
+      pSeg->xNext(p, pSeg, 0);
+      i = pIter->nSeg + iEq;
+    }
+  }
+}
+
+/*
+** Sub-iterator iChanged of iterator pIter has just been advanced. It still
+** points to the same term though - just a different rowid. This function
+** attempts to update the contents of the pIter->aFirst[] accordingly.
+** If it does so successfully, 0 is returned. Otherwise 1.
+**
+** If non-zero is returned, the caller should call fts5MultiIterAdvanced()
+** on the iterator instead. That function does the same as this one, except
+** that it deals with more complicated cases as well.
+*/
+static int fts5MultiIterAdvanceRowid(
+  Fts5Iter *pIter,                /* Iterator to update aFirst[] array for */
+  int iChanged,                   /* Index of sub-iterator just advanced */
+  Fts5SegIter **ppFirst
+){
+  Fts5SegIter *pNew = &pIter->aSeg[iChanged];
+
+  if( pNew->iRowid==pIter->iSwitchRowid
+   || (pNew->iRowid<pIter->iSwitchRowid)==pIter->bRev
+  ){
+    int i;
+    Fts5SegIter *pOther = &pIter->aSeg[iChanged ^ 0x0001];
+    pIter->iSwitchRowid = pIter->bRev ? SMALLEST_INT64 : LARGEST_INT64;
+    for(i=(pIter->nSeg+iChanged)/2; 1; i=i/2){
+      Fts5CResult *pRes = &pIter->aFirst[i];
+
+      assert( pNew->pLeaf );
+      assert( pRes->bTermEq==0 || pOther->pLeaf );
+
+      if( pRes->bTermEq ){
+        if( pNew->iRowid==pOther->iRowid ){
+          return 1;
+        }else if( (pOther->iRowid>pNew->iRowid)==pIter->bRev ){
+          pIter->iSwitchRowid = pOther->iRowid;
+          pNew = pOther;
+        }else if( (pOther->iRowid>pIter->iSwitchRowid)==pIter->bRev ){
+          pIter->iSwitchRowid = pOther->iRowid;
+        }
+      }
+      pRes->iFirst = (u16)(pNew - pIter->aSeg);
+      if( i==1 ) break;
+
+      pOther = &pIter->aSeg[ pIter->aFirst[i ^ 0x0001].iFirst ];
+    }
+  }
+
+  *ppFirst = pNew;
+  return 0;
+}
+
+/*
+** Set the pIter->bEof variable based on the state of the sub-iterators.
+*/
+static void fts5MultiIterSetEof(Fts5Iter *pIter){
+  Fts5SegIter *pSeg = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+  pIter->base.bEof = pSeg->pLeaf==0;
+  pIter->iSwitchRowid = pSeg->iRowid;
+}
+
+/*
+** The argument to this macro must be an Fts5Data structure containing a
+** tombstone hash page. This macro returns the key-size of the hash-page.
+*/
+#define TOMBSTONE_KEYSIZE(pPg) (pPg->p[0]==4 ? 4 : 8)
+
+#define TOMBSTONE_NSLOT(pPg)   \
+  ((pPg->nn > 16) ? ((pPg->nn-8) / TOMBSTONE_KEYSIZE(pPg)) : 1)
+
+/*
+** Query a single tombstone hash table for rowid iRowid. Return true if
+** it is found or false otherwise. The tombstone hash table is one of
+** nHashTable tables.
+*/
+static int fts5IndexTombstoneQuery(
+  Fts5Data *pHash,                /* Hash table page to query */
+  int nHashTable,                 /* Number of pages attached to segment */
+  u64 iRowid                      /* Rowid to query hash for */
+){
+  const int szKey = TOMBSTONE_KEYSIZE(pHash);
+  const int nSlot = TOMBSTONE_NSLOT(pHash);
+  int iSlot = (iRowid / nHashTable) % nSlot;
+  int nCollide = nSlot;
+
+  if( iRowid==0 ){
+    return pHash->p[1];
+  }else if( szKey==4 ){
+    u32 *aSlot = (u32*)&pHash->p[8];
+    while( aSlot[iSlot] ){
+      if( fts5GetU32((u8*)&aSlot[iSlot])==iRowid ) return 1;
+      if( nCollide--==0 ) break;
+      iSlot = (iSlot+1)%nSlot;
+    }
+  }else{
+    u64 *aSlot = (u64*)&pHash->p[8];
+    while( aSlot[iSlot] ){
+      if( fts5GetU64((u8*)&aSlot[iSlot])==iRowid ) return 1;
+      if( nCollide--==0 ) break;
+      iSlot = (iSlot+1)%nSlot;
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Return true if the iterator passed as the only argument points
+** to an segment entry for which there is a tombstone. Return false
+** if there is no tombstone or if the iterator is already at EOF.
+*/
+static int fts5MultiIterIsDeleted(Fts5Iter *pIter){
+  int iFirst = pIter->aFirst[1].iFirst;
+  Fts5SegIter *pSeg = &pIter->aSeg[iFirst];
+  Fts5TombstoneArray *pArray = pSeg->pTombArray;
+
+  if( pSeg->pLeaf && pArray ){
+    /* Figure out which page the rowid might be present on. */
+    int iPg = ((u64)pSeg->iRowid) % pArray->nTombstone;
+    assert( iPg>=0 );
+
+    /* If tombstone hash page iPg has not yet been loaded from the
+    ** database, load it now. */
+    if( pArray->apTombstone[iPg]==0 ){
+      pArray->apTombstone[iPg] = fts5DataRead(pIter->pIndex,
+          FTS5_TOMBSTONE_ROWID(pSeg->pSeg->iSegid, iPg)
+      );
+      if( pArray->apTombstone[iPg]==0 ) return 0;
+    }
+
+    return fts5IndexTombstoneQuery(
+        pArray->apTombstone[iPg],
+        pArray->nTombstone,
+        pSeg->iRowid
+    );
+  }
+
+  return 0;
+}
+
+/*
+** Move the iterator to the next entry.
+**
+** If an error occurs, an error code is left in Fts5Index.rc. It is not
+** considered an error if the iterator reaches EOF, or if it is already at
+** EOF when this function is called.
+*/
+static void fts5MultiIterNext(
+  Fts5Index *p,
+  Fts5Iter *pIter,
+  int bFrom,                      /* True if argument iFrom is valid */
+  i64 iFrom                       /* Advance at least as far as this */
+){
+  int bUseFrom = bFrom;
+  assert( pIter->base.bEof==0 );
+  while( p->rc==SQLITE_OK ){
+    int iFirst = pIter->aFirst[1].iFirst;
+    int bNewTerm = 0;
+    Fts5SegIter *pSeg = &pIter->aSeg[iFirst];
+    assert( p->rc==SQLITE_OK );
+    if( bUseFrom && pSeg->pDlidx ){
+      fts5SegIterNextFrom(p, pSeg, iFrom);
+    }else{
+      pSeg->xNext(p, pSeg, &bNewTerm);
+    }
+
+    if( pSeg->pLeaf==0 || bNewTerm
+     || fts5MultiIterAdvanceRowid(pIter, iFirst, &pSeg)
+    ){
+      fts5MultiIterAdvanced(p, pIter, iFirst, 1);
+      fts5MultiIterSetEof(pIter);
+      pSeg = &pIter->aSeg[pIter->aFirst[1].iFirst];
+      if( pSeg->pLeaf==0 ) return;
+    }
+
+    fts5AssertMultiIterSetup(p, pIter);
+    assert( pSeg==&pIter->aSeg[pIter->aFirst[1].iFirst] && pSeg->pLeaf );
+    if( (pIter->bSkipEmpty==0 || pSeg->nPos)
+      && 0==fts5MultiIterIsDeleted(pIter)
+    ){
+      pIter->xSetOutputs(pIter, pSeg);
+      return;
+    }
+    bUseFrom = 0;
+  }
+}
+
+static void fts5MultiIterNext2(
+  Fts5Index *p,
+  Fts5Iter *pIter,
+  int *pbNewTerm                  /* OUT: True if *might* be new term */
+){
+  assert( pIter->bSkipEmpty );
+  if( p->rc==SQLITE_OK ){
+    *pbNewTerm = 0;
+    do{
+      int iFirst = pIter->aFirst[1].iFirst;
+      Fts5SegIter *pSeg = &pIter->aSeg[iFirst];
+      int bNewTerm = 0;
+
+      assert( p->rc==SQLITE_OK );
+      pSeg->xNext(p, pSeg, &bNewTerm);
+      if( pSeg->pLeaf==0 || bNewTerm
+       || fts5MultiIterAdvanceRowid(pIter, iFirst, &pSeg)
+      ){
+        fts5MultiIterAdvanced(p, pIter, iFirst, 1);
+        fts5MultiIterSetEof(pIter);
+        *pbNewTerm = 1;
+      }
+      fts5AssertMultiIterSetup(p, pIter);
+
+    }while( (fts5MultiIterIsEmpty(p, pIter) || fts5MultiIterIsDeleted(pIter))
+         && (p->rc==SQLITE_OK)
+    );
+  }
+}
+
+static void fts5IterSetOutputs_Noop(Fts5Iter *pUnused1, Fts5SegIter *pUnused2){
+  UNUSED_PARAM2(pUnused1, pUnused2);
+}
+
+static Fts5Iter *fts5MultiIterAlloc(
+  Fts5Index *p,                   /* FTS5 backend to iterate within */
+  int nSeg
+){
+  Fts5Iter *pNew;
+  i64 nSlot;                      /* Power of two >= nSeg */
+
+  for(nSlot=2; nSlot<nSeg; nSlot=nSlot*2);
+  pNew = fts5IdxMalloc(p,
+      sizeof(Fts5Iter) +                  /* pNew */
+      sizeof(Fts5SegIter) * (nSlot-1) +   /* pNew->aSeg[] */
+      sizeof(Fts5CResult) * nSlot         /* pNew->aFirst[] */
+  );
+  if( pNew ){
+    pNew->nSeg = nSlot;
+    pNew->aFirst = (Fts5CResult*)&pNew->aSeg[nSlot];
+    pNew->pIndex = p;
+    pNew->xSetOutputs = fts5IterSetOutputs_Noop;
+  }
+  return pNew;
+}
+
+static void fts5PoslistCallback(
+  Fts5Index *pUnused,
+  void *pContext,
+  const u8 *pChunk, int nChunk
+){
+  UNUSED_PARAM(pUnused);
+  assert_nc( nChunk>=0 );
+  if( nChunk>0 ){
+    fts5BufferSafeAppendBlob((Fts5Buffer*)pContext, pChunk, nChunk);
+  }
+}
+
+typedef struct PoslistCallbackCtx PoslistCallbackCtx;
+struct PoslistCallbackCtx {
+  Fts5Buffer *pBuf;               /* Append to this buffer */
+  Fts5Colset *pColset;            /* Restrict matches to this column */
+  int eState;                     /* See above */
+};
+
+typedef struct PoslistOffsetsCtx PoslistOffsetsCtx;
+struct PoslistOffsetsCtx {
+  Fts5Buffer *pBuf;               /* Append to this buffer */
+  Fts5Colset *pColset;            /* Restrict matches to this column */
+  int iRead;
+  int iWrite;
+};
+
+/*
+** TODO: Make this more efficient!
+*/
+static int fts5IndexColsetTest(Fts5Colset *pColset, int iCol){
+  int i;
+  for(i=0; i<pColset->nCol; i++){
+    if( pColset->aiCol[i]==iCol ) return 1;
+  }
+  return 0;
+}
+
+static void fts5PoslistOffsetsCallback(
+  Fts5Index *pUnused,
+  void *pContext,
+  const u8 *pChunk, int nChunk
+){
+  PoslistOffsetsCtx *pCtx = (PoslistOffsetsCtx*)pContext;
+  UNUSED_PARAM(pUnused);
+  assert_nc( nChunk>=0 );
+  if( nChunk>0 ){
+    int i = 0;
+    while( i<nChunk ){
+      int iVal;
+      i += fts5GetVarint32(&pChunk[i], iVal);
+      iVal += pCtx->iRead - 2;
+      pCtx->iRead = iVal;
+      if( fts5IndexColsetTest(pCtx->pColset, iVal) ){
+        fts5BufferSafeAppendVarint(pCtx->pBuf, iVal + 2 - pCtx->iWrite);
+        pCtx->iWrite = iVal;
+      }
+    }
+  }
+}
+
+static void fts5PoslistFilterCallback(
+  Fts5Index *pUnused,
+  void *pContext,
+  const u8 *pChunk, int nChunk
+){
+  PoslistCallbackCtx *pCtx = (PoslistCallbackCtx*)pContext;
+  UNUSED_PARAM(pUnused);
+  assert_nc( nChunk>=0 );
+  if( nChunk>0 ){
+    /* Search through to find the first varint with value 1. This is the
+    ** start of the next columns hits. */
+    int i = 0;
+    int iStart = 0;
+
+    if( pCtx->eState==2 ){
+      int iCol;
+      fts5FastGetVarint32(pChunk, i, iCol);
+      if( fts5IndexColsetTest(pCtx->pColset, iCol) ){
+        pCtx->eState = 1;
+        fts5BufferSafeAppendVarint(pCtx->pBuf, 1);
+      }else{
+        pCtx->eState = 0;
+      }
+    }
+
+    do {
+      while( i<nChunk && pChunk[i]!=0x01 ){
+        while( pChunk[i] & 0x80 ) i++;
+        i++;
+      }
+      if( pCtx->eState ){
+        fts5BufferSafeAppendBlob(pCtx->pBuf, &pChunk[iStart], i-iStart);
+      }
+      if( i<nChunk ){
+        int iCol;
+        iStart = i;
+        i++;
+        if( i>=nChunk ){
+          pCtx->eState = 2;
+        }else{
+          fts5FastGetVarint32(pChunk, i, iCol);
+          pCtx->eState = fts5IndexColsetTest(pCtx->pColset, iCol);
+          if( pCtx->eState ){
+            fts5BufferSafeAppendBlob(pCtx->pBuf, &pChunk[iStart], i-iStart);
+            iStart = i;
+          }
+        }
+      }
+    }while( i<nChunk );
+  }
+}
+
+static void fts5ChunkIterate(
+  Fts5Index *p,                   /* Index object */
+  Fts5SegIter *pSeg,              /* Poslist of this iterator */
+  void *pCtx,                     /* Context pointer for xChunk callback */
+  void (*xChunk)(Fts5Index*, void*, const u8*, int)
+){
+  int nRem = pSeg->nPos;          /* Number of bytes still to come */
+  Fts5Data *pData = 0;
+  u8 *pChunk = &pSeg->pLeaf->p[pSeg->iLeafOffset];
+  int nChunk = MIN(nRem, pSeg->pLeaf->szLeaf - pSeg->iLeafOffset);
+  int pgno = pSeg->iLeafPgno;
+  int pgnoSave = 0;
+
+  /* This function does not work with detail=none databases. */
+  assert( p->pConfig->eDetail!=FTS5_DETAIL_NONE );
+
+  if( (pSeg->flags & FTS5_SEGITER_REVERSE)==0 ){
+    pgnoSave = pgno+1;
+  }
+
+  while( 1 ){
+    xChunk(p, pCtx, pChunk, nChunk);
+    nRem -= nChunk;
+    fts5DataRelease(pData);
+    if( nRem<=0 ){
+      break;
+    }else if( pSeg->pSeg==0 ){
+      p->rc = FTS5_CORRUPT;
+      return;
+    }else{
+      pgno++;
+      pData = fts5LeafRead(p, FTS5_SEGMENT_ROWID(pSeg->pSeg->iSegid, pgno));
+      if( pData==0 ) break;
+      pChunk = &pData->p[4];
+      nChunk = MIN(nRem, pData->szLeaf - 4);
+      if( pgno==pgnoSave ){
+        assert( pSeg->pNextLeaf==0 );
+        pSeg->pNextLeaf = pData;
+        pData = 0;
+      }
+    }
+  }
+}
+
+/*
+** Iterator pIter currently points to a valid entry (not EOF). This
+** function appends the position list data for the current entry to
+** buffer pBuf. It does not make a copy of the position-list size
+** field.
+*/
+static void fts5SegiterPoslist(
+  Fts5Index *p,
+  Fts5SegIter *pSeg,
+  Fts5Colset *pColset,
+  Fts5Buffer *pBuf
+){
+  assert( pBuf!=0 );
+  assert( pSeg!=0 );
+  if( 0==fts5BufferGrow(&p->rc, pBuf, pSeg->nPos+FTS5_DATA_ZERO_PADDING) ){
+    assert( pBuf->p!=0 );
+    assert( pBuf->nSpace >= pBuf->n+pSeg->nPos+FTS5_DATA_ZERO_PADDING );
+    memset(&pBuf->p[pBuf->n+pSeg->nPos], 0, FTS5_DATA_ZERO_PADDING);
+    if( pColset==0 ){
+      fts5ChunkIterate(p, pSeg, (void*)pBuf, fts5PoslistCallback);
+    }else{
+      if( p->pConfig->eDetail==FTS5_DETAIL_FULL ){
+        PoslistCallbackCtx sCtx;
+        sCtx.pBuf = pBuf;
+        sCtx.pColset = pColset;
+        sCtx.eState = fts5IndexColsetTest(pColset, 0);
+        assert( sCtx.eState==0 || sCtx.eState==1 );
+        fts5ChunkIterate(p, pSeg, (void*)&sCtx, fts5PoslistFilterCallback);
+      }else{
+        PoslistOffsetsCtx sCtx;
+        memset(&sCtx, 0, sizeof(sCtx));
+        sCtx.pBuf = pBuf;
+        sCtx.pColset = pColset;
+        fts5ChunkIterate(p, pSeg, (void*)&sCtx, fts5PoslistOffsetsCallback);
+      }
+    }
+  }
+}
+
+/*
+** Parameter pPos points to a buffer containing a position list, size nPos.
+** This function filters it according to pColset (which must be non-NULL)
+** and sets pIter->base.pData/nData to point to the new position list.
+** If memory is required for the new position list, use buffer pIter->poslist.
+** Or, if the new position list is a contiguous subset of the input, set
+** pIter->base.pData/nData to point directly to it.
+**
+** This function is a no-op if *pRc is other than SQLITE_OK when it is
+** called. If an OOM error is encountered, *pRc is set to SQLITE_NOMEM
+** before returning.
+*/
+static void fts5IndexExtractColset(
+  int *pRc,
+  Fts5Colset *pColset,            /* Colset to filter on */
+  const u8 *pPos, int nPos,       /* Position list */
+  Fts5Iter *pIter
+){
+  if( *pRc==SQLITE_OK ){
+    const u8 *p = pPos;
+    const u8 *aCopy = p;
+    const u8 *pEnd = &p[nPos];    /* One byte past end of position list */
+    int i = 0;
+    int iCurrent = 0;
+
+    if( pColset->nCol>1 && sqlite3Fts5BufferSize(pRc, &pIter->poslist, nPos) ){
+      return;
+    }
+
+    while( 1 ){
+      while( pColset->aiCol[i]<iCurrent ){
+        i++;
+        if( i==pColset->nCol ){
+          pIter->base.pData = pIter->poslist.p;
+          pIter->base.nData = pIter->poslist.n;
+          return;
+        }
+      }
+
+      /* Advance pointer p until it points to pEnd or an 0x01 byte that is
+      ** not part of a varint */
+      while( p<pEnd && *p!=0x01 ){
+        while( *p++ & 0x80 );
+      }
+
+      if( pColset->aiCol[i]==iCurrent ){
+        if( pColset->nCol==1 ){
+          pIter->base.pData = aCopy;
+          pIter->base.nData = p-aCopy;
+          return;
+        }
+        fts5BufferSafeAppendBlob(&pIter->poslist, aCopy, p-aCopy);
+      }
+      if( p>=pEnd ){
+        pIter->base.pData = pIter->poslist.p;
+        pIter->base.nData = pIter->poslist.n;
+        return;
+      }
+      aCopy = p++;
+      iCurrent = *p++;
+      if( iCurrent & 0x80 ){
+        p--;
+        p += fts5GetVarint32(p, iCurrent);
+      }
+    }
+  }
+
+}
+
+/*
+** xSetOutputs callback used by detail=none tables.
+*/
+static void fts5IterSetOutputs_None(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  assert( pIter->pIndex->pConfig->eDetail==FTS5_DETAIL_NONE );
+  pIter->base.iRowid = pSeg->iRowid;
+  pIter->base.nData = pSeg->nPos;
+}
+
+/*
+** xSetOutputs callback used by detail=full and detail=col tables when no
+** column filters are specified.
+*/
+static void fts5IterSetOutputs_Nocolset(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  pIter->base.iRowid = pSeg->iRowid;
+  pIter->base.nData = pSeg->nPos;
+
+  assert( pIter->pIndex->pConfig->eDetail!=FTS5_DETAIL_NONE );
+  assert( pIter->pColset==0 );
+
+  if( pSeg->iLeafOffset+pSeg->nPos<=pSeg->pLeaf->szLeaf ){
+    /* All data is stored on the current page. Populate the output
+    ** variables to point into the body of the page object. */
+    pIter->base.pData = &pSeg->pLeaf->p[pSeg->iLeafOffset];
+  }else{
+    /* The data is distributed over two or more pages. Copy it into the
+    ** Fts5Iter.poslist buffer and then set the output pointer to point
+    ** to this buffer.  */
+    fts5BufferZero(&pIter->poslist);
+    fts5SegiterPoslist(pIter->pIndex, pSeg, 0, &pIter->poslist);
+    pIter->base.pData = pIter->poslist.p;
+  }
+}
+
+/*
+** xSetOutputs callback used when the Fts5Colset object has nCol==0 (match
+** against no columns at all).
+*/
+static void fts5IterSetOutputs_ZeroColset(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  UNUSED_PARAM(pSeg);
+  pIter->base.nData = 0;
+}
+
+/*
+** xSetOutputs callback used by detail=col when there is a column filter
+** and there are 100 or more columns. Also called as a fallback from
+** fts5IterSetOutputs_Col100 if the column-list spans more than one page.
+*/
+static void fts5IterSetOutputs_Col(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  fts5BufferZero(&pIter->poslist);
+  fts5SegiterPoslist(pIter->pIndex, pSeg, pIter->pColset, &pIter->poslist);
+  pIter->base.iRowid = pSeg->iRowid;
+  pIter->base.pData = pIter->poslist.p;
+  pIter->base.nData = pIter->poslist.n;
+}
+
+/*
+** xSetOutputs callback used when:
+**
+**   * detail=col,
+**   * there is a column filter, and
+**   * the table contains 100 or fewer columns.
+**
+** The last point is to ensure all column numbers are stored as
+** single-byte varints.
+*/
+static void fts5IterSetOutputs_Col100(Fts5Iter *pIter, Fts5SegIter *pSeg){
+
+  assert( pIter->pIndex->pConfig->eDetail==FTS5_DETAIL_COLUMNS );
+  assert( pIter->pColset );
+
+  if( pSeg->iLeafOffset+pSeg->nPos>pSeg->pLeaf->szLeaf ){
+    fts5IterSetOutputs_Col(pIter, pSeg);
+  }else{
+    u8 *a = (u8*)&pSeg->pLeaf->p[pSeg->iLeafOffset];
+    u8 *pEnd = (u8*)&a[pSeg->nPos];
+    int iPrev = 0;
+    int *aiCol = pIter->pColset->aiCol;
+    int *aiColEnd = &aiCol[pIter->pColset->nCol];
+
+    u8 *aOut = pIter->poslist.p;
+    int iPrevOut = 0;
+
+    pIter->base.iRowid = pSeg->iRowid;
+
+    while( a<pEnd ){
+      iPrev += (int)a++[0] - 2;
+      while( *aiCol<iPrev ){
+        aiCol++;
+        if( aiCol==aiColEnd ) goto setoutputs_col_out;
+      }
+      if( *aiCol==iPrev ){
+        *aOut++ = (u8)((iPrev - iPrevOut) + 2);
+        iPrevOut = iPrev;
+      }
+    }
+
+setoutputs_col_out:
+    pIter->base.pData = pIter->poslist.p;
+    pIter->base.nData = aOut - pIter->poslist.p;
+  }
+}
+
+/*
+** xSetOutputs callback used by detail=full when there is a column filter.
+*/
+static void fts5IterSetOutputs_Full(Fts5Iter *pIter, Fts5SegIter *pSeg){
+  Fts5Colset *pColset = pIter->pColset;
+  pIter->base.iRowid = pSeg->iRowid;
+
+  assert( pIter->pIndex->pConfig->eDetail==FTS5_DETAIL_FULL );
+  assert( pColset );
+
+  if( pSeg->iLeafOffset+pSeg->nPos<=pSeg->pLeaf->szLeaf ){
+    /* All data is stored on the current page. Populate the output
+    ** variables to point into the body of the page object. */
+    const u8 *a = &pSeg->pLeaf->p[pSeg->iLeafOffset];
+    int *pRc = &pIter->pIndex->rc;
+    fts5BufferZero(&pIter->poslist);
+    fts5IndexExtractColset(pRc, pColset, a, pSeg->nPos, pIter);
+  }else{
+    /* The data is distributed over two or more pages. Copy it into the
+    ** Fts5Iter.poslist buffer and then set the output pointer to point
+    ** to this buffer.  */
+    fts5BufferZero(&pIter->poslist);
+    fts5SegiterPoslist(pIter->pIndex, pSeg, pColset, &pIter->poslist);
+    pIter->base.pData = pIter->poslist.p;
+    pIter->base.nData = pIter->poslist.n;
+  }
+}
+
+static void fts5IterSetOutputCb(int *pRc, Fts5Iter *pIter){
+  assert( pIter!=0 || (*pRc)!=SQLITE_OK );
+  if( *pRc==SQLITE_OK ){
+    Fts5Config *pConfig = pIter->pIndex->pConfig;
+    if( pConfig->eDetail==FTS5_DETAIL_NONE ){
+      pIter->xSetOutputs = fts5IterSetOutputs_None;
+    }
+
+    else if( pIter->pColset==0 ){
+      pIter->xSetOutputs = fts5IterSetOutputs_Nocolset;
+    }
+
+    else if( pIter->pColset->nCol==0 ){
+      pIter->xSetOutputs = fts5IterSetOutputs_ZeroColset;
+    }
+
+    else if( pConfig->eDetail==FTS5_DETAIL_FULL ){
+      pIter->xSetOutputs = fts5IterSetOutputs_Full;
+    }
+
+    else{
+      assert( pConfig->eDetail==FTS5_DETAIL_COLUMNS );
+      if( pConfig->nCol<=100 ){
+        pIter->xSetOutputs = fts5IterSetOutputs_Col100;
+        sqlite3Fts5BufferSize(pRc, &pIter->poslist, pConfig->nCol);
+      }else{
+        pIter->xSetOutputs = fts5IterSetOutputs_Col;
+      }
+    }
+  }
+}
+
+/*
+** All the component segment-iterators of pIter have been set up. This
+** functions finishes setup for iterator pIter itself.
+*/
+static void fts5MultiIterFinishSetup(Fts5Index *p, Fts5Iter *pIter){
+  int iIter;
+  for(iIter=pIter->nSeg-1; iIter>0; iIter--){
+    int iEq;
+    if( (iEq = fts5MultiIterDoCompare(pIter, iIter)) ){
+      Fts5SegIter *pSeg = &pIter->aSeg[iEq];
+      if( p->rc==SQLITE_OK ) pSeg->xNext(p, pSeg, 0);
+      fts5MultiIterAdvanced(p, pIter, iEq, iIter);
+    }
+  }
+  fts5MultiIterSetEof(pIter);
+  fts5AssertMultiIterSetup(p, pIter);
+
+  if( (pIter->bSkipEmpty && fts5MultiIterIsEmpty(p, pIter))
+   || fts5MultiIterIsDeleted(pIter)
+  ){
+    fts5MultiIterNext(p, pIter, 0, 0);
+  }else if( pIter->base.bEof==0 ){
+    Fts5SegIter *pSeg = &pIter->aSeg[pIter->aFirst[1].iFirst];
+    pIter->xSetOutputs(pIter, pSeg);
+  }
+}
+
+/*
+** Allocate a new Fts5Iter object.
+**
+** The new object will be used to iterate through data in structure pStruct.
+** If iLevel is -ve, then all data in all segments is merged. Or, if iLevel
+** is zero or greater, data from the first nSegment segments on level iLevel
+** is merged.
+**
+** The iterator initially points to the first term/rowid entry in the
+** iterated data.
+*/
+static void fts5MultiIterNew(
+  Fts5Index *p,                   /* FTS5 backend to iterate within */
+  Fts5Structure *pStruct,         /* Structure of specific index */
+  int flags,                      /* FTS5INDEX_QUERY_XXX flags */
+  Fts5Colset *pColset,            /* Colset to filter on (or NULL) */
+  const u8 *pTerm, int nTerm,     /* Term to seek to (or NULL/0) */
+  int iLevel,                     /* Level to iterate (-1 for all) */
+  int nSegment,                   /* Number of segments to merge (iLevel>=0) */
+  Fts5Iter **ppOut                /* New object */
+){
+  int nSeg = 0;                   /* Number of segment-iters in use */
+  int iIter = 0;                  /* */
+  int iSeg;                       /* Used to iterate through segments */
+  Fts5StructureLevel *pLvl;
+  Fts5Iter *pNew;
+
+  assert( (pTerm==0 && nTerm==0) || iLevel<0 );
+
+  /* Allocate space for the new multi-seg-iterator. */
+  if( p->rc==SQLITE_OK ){
+    if( iLevel<0 ){
+      assert( pStruct->nSegment==fts5StructureCountSegments(pStruct) );
+      nSeg = pStruct->nSegment;
+      nSeg += (p->pHash && 0==(flags & FTS5INDEX_QUERY_SKIPHASH));
+    }else{
+      nSeg = MIN(pStruct->aLevel[iLevel].nSeg, nSegment);
+    }
+  }
+  *ppOut = pNew = fts5MultiIterAlloc(p, nSeg);
+  if( pNew==0 ){
+    assert( p->rc!=SQLITE_OK );
+    goto fts5MultiIterNew_post_check;
+  }
+  pNew->bRev = (0!=(flags & FTS5INDEX_QUERY_DESC));
+  pNew->bSkipEmpty = (0!=(flags & FTS5INDEX_QUERY_SKIPEMPTY));
+  pNew->pColset = pColset;
+  if( (flags & FTS5INDEX_QUERY_NOOUTPUT)==0 ){
+    fts5IterSetOutputCb(&p->rc, pNew);
+  }
+
+  /* Initialize each of the component segment iterators. */
+  if( p->rc==SQLITE_OK ){
+    if( iLevel<0 ){
+      Fts5StructureLevel *pEnd = &pStruct->aLevel[pStruct->nLevel];
+      if( p->pHash && 0==(flags & FTS5INDEX_QUERY_SKIPHASH) ){
+        /* Add a segment iterator for the current contents of the hash table. */
+        Fts5SegIter *pIter = &pNew->aSeg[iIter++];
+        fts5SegIterHashInit(p, pTerm, nTerm, flags, pIter);
+      }
+      for(pLvl=&pStruct->aLevel[0]; pLvl<pEnd; pLvl++){
+        for(iSeg=pLvl->nSeg-1; iSeg>=0; iSeg--){
+          Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
+          Fts5SegIter *pIter = &pNew->aSeg[iIter++];
+          if( pTerm==0 ){
+            fts5SegIterInit(p, pSeg, pIter);
+          }else{
+            fts5SegIterSeekInit(p, pTerm, nTerm, flags, pSeg, pIter);
+          }
+        }
+      }
+    }else{
+      pLvl = &pStruct->aLevel[iLevel];
+      for(iSeg=nSeg-1; iSeg>=0; iSeg--){
+        fts5SegIterInit(p, &pLvl->aSeg[iSeg], &pNew->aSeg[iIter++]);
+      }
+    }
+    assert( iIter==nSeg );
+  }
+
+  /* If the above was successful, each component iterator now points
+  ** to the first entry in its segment. In this case initialize the
+  ** aFirst[] array. Or, if an error has occurred, free the iterator
+  ** object and set the output variable to NULL.  */
+  if( p->rc==SQLITE_OK ){
+    fts5MultiIterFinishSetup(p, pNew);
+  }else{
+    fts5MultiIterFree(pNew);
+    *ppOut = 0;
+  }
+
+fts5MultiIterNew_post_check:
+  assert( (*ppOut)!=0 || p->rc!=SQLITE_OK );
+  return;
+}
+
+/*
+** Create an Fts5Iter that iterates through the doclist provided
+** as the second argument.
+*/
+static void fts5MultiIterNew2(
+  Fts5Index *p,                   /* FTS5 backend to iterate within */
+  Fts5Data *pData,                /* Doclist to iterate through */
+  int bDesc,                      /* True for descending rowid order */
+  Fts5Iter **ppOut                /* New object */
+){
+  Fts5Iter *pNew;
+  pNew = fts5MultiIterAlloc(p, 2);
+  if( pNew ){
+    Fts5SegIter *pIter = &pNew->aSeg[1];
+    pIter->flags = FTS5_SEGITER_ONETERM;
+    if( pData->szLeaf>0 ){
+      pIter->pLeaf = pData;
+      pIter->iLeafOffset = fts5GetVarint(pData->p, (u64*)&pIter->iRowid);
+      pIter->iEndofDoclist = pData->nn;
+      pNew->aFirst[1].iFirst = 1;
+      if( bDesc ){
+        pNew->bRev = 1;
+        pIter->flags |= FTS5_SEGITER_REVERSE;
+        fts5SegIterReverseInitPage(p, pIter);
+      }else{
+        fts5SegIterLoadNPos(p, pIter);
+      }
+      pData = 0;
+    }else{
+      pNew->base.bEof = 1;
+    }
+    fts5SegIterSetNext(p, pIter);
+
+    *ppOut = pNew;
+  }
+
+  fts5DataRelease(pData);
+}
+
+/*
+** Return true if the iterator is at EOF or if an error has occurred.
+** False otherwise.
+*/
+static int fts5MultiIterEof(Fts5Index *p, Fts5Iter *pIter){
+  assert( pIter!=0 || p->rc!=SQLITE_OK );
+  assert( p->rc!=SQLITE_OK
+      || (pIter->aSeg[ pIter->aFirst[1].iFirst ].pLeaf==0)==pIter->base.bEof
+  );
+  return (p->rc || pIter->base.bEof);
+}
+
+/*
+** Return the rowid of the entry that the iterator currently points
+** to. If the iterator points to EOF when this function is called the
+** results are undefined.
+*/
+static i64 fts5MultiIterRowid(Fts5Iter *pIter){
+  assert( pIter->aSeg[ pIter->aFirst[1].iFirst ].pLeaf );
+  return pIter->aSeg[ pIter->aFirst[1].iFirst ].iRowid;
+}
+
+/*
+** Move the iterator to the next entry at or following iMatch.
+*/
+static void fts5MultiIterNextFrom(
+  Fts5Index *p,
+  Fts5Iter *pIter,
+  i64 iMatch
+){
+  while( 1 ){
+    i64 iRowid;
+    fts5MultiIterNext(p, pIter, 1, iMatch);
+    if( fts5MultiIterEof(p, pIter) ) break;
+    iRowid = fts5MultiIterRowid(pIter);
+    if( pIter->bRev==0 && iRowid>=iMatch ) break;
+    if( pIter->bRev!=0 && iRowid<=iMatch ) break;
+  }
+}
+
+/*
+** Return a pointer to a buffer containing the term associated with the
+** entry that the iterator currently points to.
+*/
+static const u8 *fts5MultiIterTerm(Fts5Iter *pIter, int *pn){
+  Fts5SegIter *p = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+  *pn = p->term.n;
+  return p->term.p;
+}
+
+/*
+** Allocate a new segment-id for the structure pStruct. The new segment
+** id must be between 1 and 65335 inclusive, and must not be used by
+** any currently existing segment. If a free segment id cannot be found,
+** SQLITE_FULL is returned.
+**
+** If an error has already occurred, this function is a no-op. 0 is
+** returned in this case.
+*/
+static int fts5AllocateSegid(Fts5Index *p, Fts5Structure *pStruct){
+  int iSegid = 0;
+
+  if( p->rc==SQLITE_OK ){
+    if( pStruct->nSegment>=FTS5_MAX_SEGMENT ){
+      p->rc = SQLITE_FULL;
+    }else{
+      /* FTS5_MAX_SEGMENT is currently defined as 2000. So the following
+      ** array is 63 elements, or 252 bytes, in size.  */
+      u32 aUsed[(FTS5_MAX_SEGMENT+31) / 32];
+      int iLvl, iSeg;
+      int i;
+      u32 mask;
+      memset(aUsed, 0, sizeof(aUsed));
+      for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+        for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
+          int iId = pStruct->aLevel[iLvl].aSeg[iSeg].iSegid;
+          if( iId<=FTS5_MAX_SEGMENT && iId>0 ){
+            aUsed[(iId-1) / 32] |= (u32)1 << ((iId-1) % 32);
+          }
+        }
+      }
+
+      for(i=0; aUsed[i]==0xFFFFFFFF; i++);
+      mask = aUsed[i];
+      for(iSegid=0; mask & ((u32)1 << iSegid); iSegid++);
+      iSegid += 1 + i*32;
+
+#ifdef SQLITE_DEBUG
+      for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+        for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
+          assert_nc( iSegid!=pStruct->aLevel[iLvl].aSeg[iSeg].iSegid );
+        }
+      }
+      assert_nc( iSegid>0 && iSegid<=FTS5_MAX_SEGMENT );
+
+      {
+        sqlite3_stmt *pIdxSelect = fts5IdxSelectStmt(p);
+        if( p->rc==SQLITE_OK ){
+          u8 aBlob[2] = {0xff, 0xff};
+          sqlite3_bind_int(pIdxSelect, 1, iSegid);
+          sqlite3_bind_blob(pIdxSelect, 2, aBlob, 2, SQLITE_STATIC);
+          assert_nc( sqlite3_step(pIdxSelect)!=SQLITE_ROW );
+          p->rc = sqlite3_reset(pIdxSelect);
+          sqlite3_bind_null(pIdxSelect, 2);
+        }
+      }
+#endif
+    }
+  }
+
+  return iSegid;
+}
+
+/*
+** Discard all data currently cached in the hash-tables.
+*/
+static void fts5IndexDiscardData(Fts5Index *p){
+  assert( p->pHash || p->nPendingData==0 );
+  if( p->pHash ){
+    sqlite3Fts5HashClear(p->pHash);
+    p->nPendingData = 0;
+    p->nPendingRow = 0;
+    p->flushRc = SQLITE_OK;
+  }
+  p->nContentlessDelete = 0;
+}
+
+/*
+** Return the size of the prefix, in bytes, that buffer
+** (pNew/<length-unknown>) shares with buffer (pOld/nOld).
+**
+** Buffer (pNew/<length-unknown>) is guaranteed to be greater
+** than buffer (pOld/nOld).
+*/
+static int fts5PrefixCompress(int nOld, const u8 *pOld, const u8 *pNew){
+  int i;
+  for(i=0; i<nOld; i++){
+    if( pOld[i]!=pNew[i] ) break;
+  }
+  return i;
+}
+
+static void fts5WriteDlidxClear(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  int bFlush                      /* If true, write dlidx to disk */
+){
+  int i;
+  assert( bFlush==0 || (pWriter->nDlidx>0 && pWriter->aDlidx[0].buf.n>0) );
+  for(i=0; i<pWriter->nDlidx; i++){
+    Fts5DlidxWriter *pDlidx = &pWriter->aDlidx[i];
+    if( pDlidx->buf.n==0 ) break;
+    if( bFlush ){
+      assert( pDlidx->pgno!=0 );
+      fts5DataWrite(p,
+          FTS5_DLIDX_ROWID(pWriter->iSegid, i, pDlidx->pgno),
+          pDlidx->buf.p, pDlidx->buf.n
+      );
+    }
+    sqlite3Fts5BufferZero(&pDlidx->buf);
+    pDlidx->bPrevValid = 0;
+  }
+}
+
+/*
+** Grow the pWriter->aDlidx[] array to at least nLvl elements in size.
+** Any new array elements are zeroed before returning.
+*/
+static int fts5WriteDlidxGrow(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  int nLvl
+){
+  if( p->rc==SQLITE_OK && nLvl>=pWriter->nDlidx ){
+    Fts5DlidxWriter *aDlidx = (Fts5DlidxWriter*)sqlite3_realloc64(
+        pWriter->aDlidx, sizeof(Fts5DlidxWriter) * nLvl
+    );
+    if( aDlidx==0 ){
+      p->rc = SQLITE_NOMEM;
+    }else{
+      size_t nByte = sizeof(Fts5DlidxWriter) * (nLvl - pWriter->nDlidx);
+      memset(&aDlidx[pWriter->nDlidx], 0, nByte);
+      pWriter->aDlidx = aDlidx;
+      pWriter->nDlidx = nLvl;
+    }
+  }
+  return p->rc;
+}
+
+/*
+** If the current doclist-index accumulating in pWriter->aDlidx[] is large
+** enough, flush it to disk and return 1. Otherwise discard it and return
+** zero.
+*/
+static int fts5WriteFlushDlidx(Fts5Index *p, Fts5SegWriter *pWriter){
+  int bFlag = 0;
+
+  /* If there were FTS5_MIN_DLIDX_SIZE or more empty leaf pages written
+  ** to the database, also write the doclist-index to disk.  */
+  if( pWriter->aDlidx[0].buf.n>0 && pWriter->nEmpty>=FTS5_MIN_DLIDX_SIZE ){
+    bFlag = 1;
+  }
+  fts5WriteDlidxClear(p, pWriter, bFlag);
+  pWriter->nEmpty = 0;
+  return bFlag;
+}
+
+/*
+** This function is called whenever processing of the doclist for the
+** last term on leaf page (pWriter->iBtPage) is completed.
+**
+** The doclist-index for that term is currently stored in-memory within the
+** Fts5SegWriter.aDlidx[] array. If it is large enough, this function
+** writes it out to disk. Or, if it is too small to bother with, discards
+** it.
+**
+** Fts5SegWriter.btterm currently contains the first term on page iBtPage.
+*/
+static void fts5WriteFlushBtree(Fts5Index *p, Fts5SegWriter *pWriter){
+  int bFlag;
+
+  assert( pWriter->iBtPage || pWriter->nEmpty==0 );
+  if( pWriter->iBtPage==0 ) return;
+  bFlag = fts5WriteFlushDlidx(p, pWriter);
+
+  if( p->rc==SQLITE_OK ){
+    const char *z = (pWriter->btterm.n>0?(const char*)pWriter->btterm.p:"");
+    /* The following was already done in fts5WriteInit(): */
+    /* sqlite3_bind_int(p->pIdxWriter, 1, pWriter->iSegid); */
+    sqlite3_bind_blob(p->pIdxWriter, 2, z, pWriter->btterm.n, SQLITE_STATIC);
+    sqlite3_bind_int64(p->pIdxWriter, 3, bFlag + ((i64)pWriter->iBtPage<<1));
+    sqlite3_step(p->pIdxWriter);
+    p->rc = sqlite3_reset(p->pIdxWriter);
+    sqlite3_bind_null(p->pIdxWriter, 2);
+  }
+  pWriter->iBtPage = 0;
+}
+
+/*
+** This is called once for each leaf page except the first that contains
+** at least one term. Argument (nTerm/pTerm) is the split-key - a term that
+** is larger than all terms written to earlier leaves, and equal to or
+** smaller than the first term on the new leaf.
+**
+** If an error occurs, an error code is left in Fts5Index.rc. If an error
+** has already occurred when this function is called, it is a no-op.
+*/
+static void fts5WriteBtreeTerm(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegWriter *pWriter,         /* Writer object */
+  int nTerm, const u8 *pTerm      /* First term on new page */
+){
+  fts5WriteFlushBtree(p, pWriter);
+  if( p->rc==SQLITE_OK ){
+    fts5BufferSet(&p->rc, &pWriter->btterm, nTerm, pTerm);
+    pWriter->iBtPage = pWriter->writer.pgno;
+  }
+}
+
+/*
+** This function is called when flushing a leaf page that contains no
+** terms at all to disk.
+*/
+static void fts5WriteBtreeNoTerm(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5SegWriter *pWriter          /* Writer object */
+){
+  /* If there were no rowids on the leaf page either and the doclist-index
+  ** has already been started, append an 0x00 byte to it.  */
+  if( pWriter->bFirstRowidInPage && pWriter->aDlidx[0].buf.n>0 ){
+    Fts5DlidxWriter *pDlidx = &pWriter->aDlidx[0];
+    assert( pDlidx->bPrevValid );
+    sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx->buf, 0);
+  }
+
+  /* Increment the "number of sequential leaves without a term" counter. */
+  pWriter->nEmpty++;
+}
+
+static i64 fts5DlidxExtractFirstRowid(Fts5Buffer *pBuf){
+  i64 iRowid;
+  int iOff;
+
+  iOff = 1 + fts5GetVarint(&pBuf->p[1], (u64*)&iRowid);
+  fts5GetVarint(&pBuf->p[iOff], (u64*)&iRowid);
+  return iRowid;
+}
+
+/*
+** Rowid iRowid has just been appended to the current leaf page. It is the
+** first on the page. This function appends an appropriate entry to the current
+** doclist-index.
+*/
+static void fts5WriteDlidxAppend(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  i64 iRowid
+){
+  int i;
+  int bDone = 0;
+
+  for(i=0; p->rc==SQLITE_OK && bDone==0; i++){
+    i64 iVal;
+    Fts5DlidxWriter *pDlidx = &pWriter->aDlidx[i];
+
+    if( pDlidx->buf.n>=p->pConfig->pgsz ){
+      /* The current doclist-index page is full. Write it to disk and push
+      ** a copy of iRowid (which will become the first rowid on the next
+      ** doclist-index leaf page) up into the next level of the b-tree
+      ** hierarchy. If the node being flushed is currently the root node,
+      ** also push its first rowid upwards. */
+      pDlidx->buf.p[0] = 0x01;    /* Not the root node */
+      fts5DataWrite(p,
+          FTS5_DLIDX_ROWID(pWriter->iSegid, i, pDlidx->pgno),
+          pDlidx->buf.p, pDlidx->buf.n
+      );
+      fts5WriteDlidxGrow(p, pWriter, i+2);
+      pDlidx = &pWriter->aDlidx[i];
+      if( p->rc==SQLITE_OK && pDlidx[1].buf.n==0 ){
+        i64 iFirst = fts5DlidxExtractFirstRowid(&pDlidx->buf);
+
+        /* This was the root node. Push its first rowid up to the new root. */
+        pDlidx[1].pgno = pDlidx->pgno;
+        sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx[1].buf, 0);
+        sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx[1].buf, pDlidx->pgno);
+        sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx[1].buf, iFirst);
+        pDlidx[1].bPrevValid = 1;
+        pDlidx[1].iPrev = iFirst;
+      }
+
+      sqlite3Fts5BufferZero(&pDlidx->buf);
+      pDlidx->bPrevValid = 0;
+      pDlidx->pgno++;
+    }else{
+      bDone = 1;
+    }
+
+    if( pDlidx->bPrevValid ){
+      iVal = (u64)iRowid - (u64)pDlidx->iPrev;
+    }else{
+      i64 iPgno = (i==0 ? pWriter->writer.pgno : pDlidx[-1].pgno);
+      assert( pDlidx->buf.n==0 );
+      sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx->buf, !bDone);
+      sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx->buf, iPgno);
+      iVal = iRowid;
+    }
+
+    sqlite3Fts5BufferAppendVarint(&p->rc, &pDlidx->buf, iVal);
+    pDlidx->bPrevValid = 1;
+    pDlidx->iPrev = iRowid;
+  }
+}
+
+static void fts5WriteFlushLeaf(Fts5Index *p, Fts5SegWriter *pWriter){
+  static const u8 zero[] = { 0x00, 0x00, 0x00, 0x00 };
+  Fts5PageWriter *pPage = &pWriter->writer;
+  i64 iRowid;
+
+  assert( (pPage->pgidx.n==0)==(pWriter->bFirstTermInPage) );
+
+  /* Set the szLeaf header field. */
+  assert( 0==fts5GetU16(&pPage->buf.p[2]) );
+  fts5PutU16(&pPage->buf.p[2], (u16)pPage->buf.n);
+
+  if( pWriter->bFirstTermInPage ){
+    /* No term was written to this page. */
+    assert( pPage->pgidx.n==0 );
+    fts5WriteBtreeNoTerm(p, pWriter);
+  }else{
+    /* Append the pgidx to the page buffer. Set the szLeaf header field. */
+    fts5BufferAppendBlob(&p->rc, &pPage->buf, pPage->pgidx.n, pPage->pgidx.p);
+  }
+
+  /* Write the page out to disk */
+  iRowid = FTS5_SEGMENT_ROWID(pWriter->iSegid, pPage->pgno);
+  fts5DataWrite(p, iRowid, pPage->buf.p, pPage->buf.n);
+
+  /* Initialize the next page. */
+  fts5BufferZero(&pPage->buf);
+  fts5BufferZero(&pPage->pgidx);
+  fts5BufferAppendBlob(&p->rc, &pPage->buf, 4, zero);
+  pPage->iPrevPgidx = 0;
+  pPage->pgno++;
+
+  /* Increase the leaves written counter */
+  pWriter->nLeafWritten++;
+
+  /* The new leaf holds no terms or rowids */
+  pWriter->bFirstTermInPage = 1;
+  pWriter->bFirstRowidInPage = 1;
+}
+
+/*
+** Append term pTerm/nTerm to the segment being written by the writer passed
+** as the second argument.
+**
+** If an error occurs, set the Fts5Index.rc error code. If an error has
+** already occurred, this function is a no-op.
+*/
+static void fts5WriteAppendTerm(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  int nTerm, const u8 *pTerm
+){
+  int nPrefix;                    /* Bytes of prefix compression for term */
+  Fts5PageWriter *pPage = &pWriter->writer;
+  Fts5Buffer *pPgidx = &pWriter->writer.pgidx;
+  int nMin = MIN(pPage->term.n, nTerm);
+
+  assert( p->rc==SQLITE_OK );
+  assert( pPage->buf.n>=4 );
+  assert( pPage->buf.n>4 || pWriter->bFirstTermInPage );
+
+  /* If the current leaf page is full, flush it to disk. */
+  if( (pPage->buf.n + pPgidx->n + nTerm + 2)>=p->pConfig->pgsz ){
+    if( pPage->buf.n>4 ){
+      fts5WriteFlushLeaf(p, pWriter);
+      if( p->rc!=SQLITE_OK ) return;
+    }
+    fts5BufferGrow(&p->rc, &pPage->buf, nTerm+FTS5_DATA_PADDING);
+  }
+
+  /* TODO1: Updating pgidx here. */
+  pPgidx->n += sqlite3Fts5PutVarint(
+      &pPgidx->p[pPgidx->n], pPage->buf.n - pPage->iPrevPgidx
+  );
+  pPage->iPrevPgidx = pPage->buf.n;
+#if 0
+  fts5PutU16(&pPgidx->p[pPgidx->n], pPage->buf.n);
+  pPgidx->n += 2;
+#endif
+
+  if( pWriter->bFirstTermInPage ){
+    nPrefix = 0;
+    if( pPage->pgno!=1 ){
+      /* This is the first term on a leaf that is not the leftmost leaf in
+      ** the segment b-tree. In this case it is necessary to add a term to
+      ** the b-tree hierarchy that is (a) larger than the largest term
+      ** already written to the segment and (b) smaller than or equal to
+      ** this term. In other words, a prefix of (pTerm/nTerm) that is one
+      ** byte longer than the longest prefix (pTerm/nTerm) shares with the
+      ** previous term.
+      **
+      ** Usually, the previous term is available in pPage->term. The exception
+      ** is if this is the first term written in an incremental-merge step.
+      ** In this case the previous term is not available, so just write a
+      ** copy of (pTerm/nTerm) into the parent node. This is slightly
+      ** inefficient, but still correct.  */
+      int n = nTerm;
+      if( pPage->term.n ){
+        n = 1 + fts5PrefixCompress(nMin, pPage->term.p, pTerm);
+      }
+      fts5WriteBtreeTerm(p, pWriter, n, pTerm);
+      if( p->rc!=SQLITE_OK ) return;
+      pPage = &pWriter->writer;
+    }
+  }else{
+    nPrefix = fts5PrefixCompress(nMin, pPage->term.p, pTerm);
+    fts5BufferAppendVarint(&p->rc, &pPage->buf, nPrefix);
+  }
+
+  /* Append the number of bytes of new data, then the term data itself
+  ** to the page. */
+  fts5BufferAppendVarint(&p->rc, &pPage->buf, nTerm - nPrefix);
+  fts5BufferAppendBlob(&p->rc, &pPage->buf, nTerm - nPrefix, &pTerm[nPrefix]);
+
+  /* Update the Fts5PageWriter.term field. */
+  fts5BufferSet(&p->rc, &pPage->term, nTerm, pTerm);
+  pWriter->bFirstTermInPage = 0;
+
+  pWriter->bFirstRowidInPage = 0;
+  pWriter->bFirstRowidInDoclist = 1;
+
+  assert( p->rc || (pWriter->nDlidx>0 && pWriter->aDlidx[0].buf.n==0) );
+  pWriter->aDlidx[0].pgno = pPage->pgno;
+}
+
+/*
+** Append a rowid and position-list size field to the writers output.
+*/
+static void fts5WriteAppendRowid(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  i64 iRowid
+){
+  if( p->rc==SQLITE_OK ){
+    Fts5PageWriter *pPage = &pWriter->writer;
+
+    if( (pPage->buf.n + pPage->pgidx.n)>=p->pConfig->pgsz ){
+      fts5WriteFlushLeaf(p, pWriter);
+    }
+
+    /* If this is to be the first rowid written to the page, set the
+    ** rowid-pointer in the page-header. Also append a value to the dlidx
+    ** buffer, in case a doclist-index is required.  */
+    if( pWriter->bFirstRowidInPage ){
+      fts5PutU16(pPage->buf.p, (u16)pPage->buf.n);
+      fts5WriteDlidxAppend(p, pWriter, iRowid);
+    }
+
+    /* Write the rowid. */
+    if( pWriter->bFirstRowidInDoclist || pWriter->bFirstRowidInPage ){
+      fts5BufferAppendVarint(&p->rc, &pPage->buf, iRowid);
+    }else{
+      assert_nc( p->rc || iRowid>pWriter->iPrevRowid );
+      fts5BufferAppendVarint(&p->rc, &pPage->buf,
+          (u64)iRowid - (u64)pWriter->iPrevRowid
+      );
+    }
+    pWriter->iPrevRowid = iRowid;
+    pWriter->bFirstRowidInDoclist = 0;
+    pWriter->bFirstRowidInPage = 0;
+  }
+}
+
+static void fts5WriteAppendPoslistData(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  const u8 *aData,
+  int nData
+){
+  Fts5PageWriter *pPage = &pWriter->writer;
+  const u8 *a = aData;
+  int n = nData;
+
+  assert( p->pConfig->pgsz>0 || p->rc!=SQLITE_OK );
+  while( p->rc==SQLITE_OK
+     && (pPage->buf.n + pPage->pgidx.n + n)>=p->pConfig->pgsz
+  ){
+    int nReq = p->pConfig->pgsz - pPage->buf.n - pPage->pgidx.n;
+    int nCopy = 0;
+    while( nCopy<nReq ){
+      i64 dummy;
+      nCopy += fts5GetVarint(&a[nCopy], (u64*)&dummy);
+    }
+    fts5BufferAppendBlob(&p->rc, &pPage->buf, nCopy, a);
+    a += nCopy;
+    n -= nCopy;
+    fts5WriteFlushLeaf(p, pWriter);
+  }
+  if( n>0 ){
+    fts5BufferAppendBlob(&p->rc, &pPage->buf, n, a);
+  }
+}
+
+/*
+** Flush any data cached by the writer object to the database. Free any
+** allocations associated with the writer.
+*/
+static void fts5WriteFinish(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,         /* Writer object */
+  int *pnLeaf                     /* OUT: Number of leaf pages in b-tree */
+){
+  int i;
+  Fts5PageWriter *pLeaf = &pWriter->writer;
+  if( p->rc==SQLITE_OK ){
+    assert( pLeaf->pgno>=1 );
+    if( pLeaf->buf.n>4 ){
+      fts5WriteFlushLeaf(p, pWriter);
+    }
+    *pnLeaf = pLeaf->pgno-1;
+    if( pLeaf->pgno>1 ){
+      fts5WriteFlushBtree(p, pWriter);
+    }
+  }
+  fts5BufferFree(&pLeaf->term);
+  fts5BufferFree(&pLeaf->buf);
+  fts5BufferFree(&pLeaf->pgidx);
+  fts5BufferFree(&pWriter->btterm);
+
+  for(i=0; i<pWriter->nDlidx; i++){
+    sqlite3Fts5BufferFree(&pWriter->aDlidx[i].buf);
+  }
+  sqlite3_free(pWriter->aDlidx);
+}
+
+static void fts5WriteInit(
+  Fts5Index *p,
+  Fts5SegWriter *pWriter,
+  int iSegid
+){
+  const int nBuffer = p->pConfig->pgsz + FTS5_DATA_PADDING;
+
+  memset(pWriter, 0, sizeof(Fts5SegWriter));
+  pWriter->iSegid = iSegid;
+
+  fts5WriteDlidxGrow(p, pWriter, 1);
+  pWriter->writer.pgno = 1;
+  pWriter->bFirstTermInPage = 1;
+  pWriter->iBtPage = 1;
+
+  assert( pWriter->writer.buf.n==0 );
+  assert( pWriter->writer.pgidx.n==0 );
+
+  /* Grow the two buffers to pgsz + padding bytes in size. */
+  sqlite3Fts5BufferSize(&p->rc, &pWriter->writer.pgidx, nBuffer);
+  sqlite3Fts5BufferSize(&p->rc, &pWriter->writer.buf, nBuffer);
+
+  if( p->pIdxWriter==0 ){
+    Fts5Config *pConfig = p->pConfig;
+    fts5IndexPrepareStmt(p, &p->pIdxWriter, sqlite3_mprintf(
+          "INSERT INTO '%q'.'%q_idx'(segid,term,pgno) VALUES(?,?,?)",
+          pConfig->zDb, pConfig->zName
+    ));
+  }
+
+  if( p->rc==SQLITE_OK ){
+    /* Initialize the 4-byte leaf-page header to 0x00. */
+    memset(pWriter->writer.buf.p, 0, 4);
+    pWriter->writer.buf.n = 4;
+
+    /* Bind the current output segment id to the index-writer. This is an
+    ** optimization over binding the same value over and over as rows are
+    ** inserted into %_idx by the current writer.  */
+    sqlite3_bind_int(p->pIdxWriter, 1, pWriter->iSegid);
+  }
+}
+
+/*
+** Iterator pIter was used to iterate through the input segments of on an
+** incremental merge operation. This function is called if the incremental
+** merge step has finished but the input has not been completely exhausted.
+*/
+static void fts5TrimSegments(Fts5Index *p, Fts5Iter *pIter){
+  int i;
+  Fts5Buffer buf;
+  memset(&buf, 0, sizeof(Fts5Buffer));
+  for(i=0; i<pIter->nSeg && p->rc==SQLITE_OK; i++){
+    Fts5SegIter *pSeg = &pIter->aSeg[i];
+    if( pSeg->pSeg==0 ){
+      /* no-op */
+    }else if( pSeg->pLeaf==0 ){
+      /* All keys from this input segment have been transfered to the output.
+      ** Set both the first and last page-numbers to 0 to indicate that the
+      ** segment is now empty. */
+      pSeg->pSeg->pgnoLast = 0;
+      pSeg->pSeg->pgnoFirst = 0;
+    }else{
+      int iOff = pSeg->iTermLeafOffset;     /* Offset on new first leaf page */
+      i64 iLeafRowid;
+      Fts5Data *pData;
+      int iId = pSeg->pSeg->iSegid;
+      u8 aHdr[4] = {0x00, 0x00, 0x00, 0x00};
+
+      iLeafRowid = FTS5_SEGMENT_ROWID(iId, pSeg->iTermLeafPgno);
+      pData = fts5LeafRead(p, iLeafRowid);
+      if( pData ){
+        if( iOff>pData->szLeaf ){
+          /* This can occur if the pages that the segments occupy overlap - if
+          ** a single page has been assigned to more than one segment. In
+          ** this case a prior iteration of this loop may have corrupted the
+          ** segment currently being trimmed.  */
+          p->rc = FTS5_CORRUPT;
+        }else{
+          fts5BufferZero(&buf);
+          fts5BufferGrow(&p->rc, &buf, pData->nn);
+          fts5BufferAppendBlob(&p->rc, &buf, sizeof(aHdr), aHdr);
+          fts5BufferAppendVarint(&p->rc, &buf, pSeg->term.n);
+          fts5BufferAppendBlob(&p->rc, &buf, pSeg->term.n, pSeg->term.p);
+          fts5BufferAppendBlob(&p->rc, &buf,pData->szLeaf-iOff,&pData->p[iOff]);
+          if( p->rc==SQLITE_OK ){
+            /* Set the szLeaf field */
+            fts5PutU16(&buf.p[2], (u16)buf.n);
+          }
+
+          /* Set up the new page-index array */
+          fts5BufferAppendVarint(&p->rc, &buf, 4);
+          if( pSeg->iLeafPgno==pSeg->iTermLeafPgno
+           && pSeg->iEndofDoclist<pData->szLeaf
+           && pSeg->iPgidxOff<=pData->nn
+          ){
+            int nDiff = pData->szLeaf - pSeg->iEndofDoclist;
+            fts5BufferAppendVarint(&p->rc, &buf, buf.n - 1 - nDiff - 4);
+            fts5BufferAppendBlob(&p->rc, &buf,
+                pData->nn - pSeg->iPgidxOff, &pData->p[pSeg->iPgidxOff]
+            );
+          }
+
+          pSeg->pSeg->pgnoFirst = pSeg->iTermLeafPgno;
+          fts5DataDelete(p, FTS5_SEGMENT_ROWID(iId, 1), iLeafRowid);
+          fts5DataWrite(p, iLeafRowid, buf.p, buf.n);
+        }
+        fts5DataRelease(pData);
+      }
+    }
+  }
+  fts5BufferFree(&buf);
+}
+
+static void fts5MergeChunkCallback(
+  Fts5Index *p,
+  void *pCtx,
+  const u8 *pChunk, int nChunk
+){
+  Fts5SegWriter *pWriter = (Fts5SegWriter*)pCtx;
+  fts5WriteAppendPoslistData(p, pWriter, pChunk, nChunk);
+}
+
+/*
+**
+*/
+static void fts5IndexMergeLevel(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Structure **ppStruct,       /* IN/OUT: Stucture of index */
+  int iLvl,                       /* Level to read input from */
+  int *pnRem                      /* Write up to this many output leaves */
+){
+  Fts5Structure *pStruct = *ppStruct;
+  Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
+  Fts5StructureLevel *pLvlOut;
+  Fts5Iter *pIter = 0;       /* Iterator to read input data */
+  int nRem = pnRem ? *pnRem : 0;  /* Output leaf pages left to write */
+  int nInput;                     /* Number of input segments */
+  Fts5SegWriter writer;           /* Writer object */
+  Fts5StructureSegment *pSeg;     /* Output segment */
+  Fts5Buffer term;
+  int bOldest;                    /* True if the output segment is the oldest */
+  int eDetail = p->pConfig->eDetail;
+  const int flags = FTS5INDEX_QUERY_NOOUTPUT;
+  int bTermWritten = 0;           /* True if current term already output */
+
+  assert( iLvl<pStruct->nLevel );
+  assert( pLvl->nMerge<=pLvl->nSeg );
+
+  memset(&writer, 0, sizeof(Fts5SegWriter));
+  memset(&term, 0, sizeof(Fts5Buffer));
+  if( pLvl->nMerge ){
+    pLvlOut = &pStruct->aLevel[iLvl+1];
+    assert( pLvlOut->nSeg>0 );
+    nInput = pLvl->nMerge;
+    pSeg = &pLvlOut->aSeg[pLvlOut->nSeg-1];
+
+    fts5WriteInit(p, &writer, pSeg->iSegid);
+    writer.writer.pgno = pSeg->pgnoLast+1;
+    writer.iBtPage = 0;
+  }else{
+    int iSegid = fts5AllocateSegid(p, pStruct);
+
+    /* Extend the Fts5Structure object as required to ensure the output
+    ** segment exists. */
+    if( iLvl==pStruct->nLevel-1 ){
+      fts5StructureAddLevel(&p->rc, ppStruct);
+      pStruct = *ppStruct;
+    }
+    fts5StructureExtendLevel(&p->rc, pStruct, iLvl+1, 1, 0);
+    if( p->rc ) return;
+    pLvl = &pStruct->aLevel[iLvl];
+    pLvlOut = &pStruct->aLevel[iLvl+1];
+
+    fts5WriteInit(p, &writer, iSegid);
+
+    /* Add the new segment to the output level */
+    pSeg = &pLvlOut->aSeg[pLvlOut->nSeg];
+    pLvlOut->nSeg++;
+    pSeg->pgnoFirst = 1;
+    pSeg->iSegid = iSegid;
+    pStruct->nSegment++;
+
+    /* Read input from all segments in the input level */
+    nInput = pLvl->nSeg;
+
+    /* Set the range of origins that will go into the output segment. */
+    if( pStruct->nOriginCntr>0 ){
+      pSeg->iOrigin1 = pLvl->aSeg[0].iOrigin1;
+      pSeg->iOrigin2 = pLvl->aSeg[pLvl->nSeg-1].iOrigin2;
+    }
+  }
+  bOldest = (pLvlOut->nSeg==1 && pStruct->nLevel==iLvl+2);
+
+  assert( iLvl>=0 );
+  for(fts5MultiIterNew(p, pStruct, flags, 0, 0, 0, iLvl, nInput, &pIter);
+      fts5MultiIterEof(p, pIter)==0;
+      fts5MultiIterNext(p, pIter, 0, 0)
+  ){
+    Fts5SegIter *pSegIter = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+    int nPos;                     /* position-list size field value */
+    int nTerm;
+    const u8 *pTerm;
+
+    pTerm = fts5MultiIterTerm(pIter, &nTerm);
+    if( nTerm!=term.n || fts5Memcmp(pTerm, term.p, nTerm) ){
+      if( pnRem && writer.nLeafWritten>nRem ){
+        break;
+      }
+      fts5BufferSet(&p->rc, &term, nTerm, pTerm);
+      bTermWritten =0;
+    }
+
+    /* Check for key annihilation. */
+    if( pSegIter->nPos==0 && (bOldest || pSegIter->bDel==0) ) continue;
+
+    if( p->rc==SQLITE_OK && bTermWritten==0 ){
+      /* This is a new term. Append a term to the output segment. */
+      fts5WriteAppendTerm(p, &writer, nTerm, pTerm);
+      bTermWritten = 1;
+    }
+
+    /* Append the rowid to the output */
+    /* WRITEPOSLISTSIZE */
+    fts5WriteAppendRowid(p, &writer, fts5MultiIterRowid(pIter));
+
+    if( eDetail==FTS5_DETAIL_NONE ){
+      if( pSegIter->bDel ){
+        fts5BufferAppendVarint(&p->rc, &writer.writer.buf, 0);
+        if( pSegIter->nPos>0 ){
+          fts5BufferAppendVarint(&p->rc, &writer.writer.buf, 0);
+        }
+      }
+    }else{
+      /* Append the position-list data to the output */
+      nPos = pSegIter->nPos*2 + pSegIter->bDel;
+      fts5BufferAppendVarint(&p->rc, &writer.writer.buf, nPos);
+      fts5ChunkIterate(p, pSegIter, (void*)&writer, fts5MergeChunkCallback);
+    }
+  }
+
+  /* Flush the last leaf page to disk. Set the output segment b-tree height
+  ** and last leaf page number at the same time.  */
+  fts5WriteFinish(p, &writer, &pSeg->pgnoLast);
+
+  assert( pIter!=0 || p->rc!=SQLITE_OK );
+  if( fts5MultiIterEof(p, pIter) ){
+    int i;
+
+    /* Remove the redundant segments from the %_data table */
+    assert( pSeg->nEntry==0 );
+    for(i=0; i<nInput; i++){
+      Fts5StructureSegment *pOld = &pLvl->aSeg[i];
+      pSeg->nEntry += (pOld->nEntry - pOld->nEntryTombstone);
+      fts5DataRemoveSegment(p, pOld);
+    }
+
+    /* Remove the redundant segments from the input level */
+    if( pLvl->nSeg!=nInput ){
+      int nMove = (pLvl->nSeg - nInput) * sizeof(Fts5StructureSegment);
+      memmove(pLvl->aSeg, &pLvl->aSeg[nInput], nMove);
+    }
+    pStruct->nSegment -= nInput;
+    pLvl->nSeg -= nInput;
+    pLvl->nMerge = 0;
+    if( pSeg->pgnoLast==0 ){
+      pLvlOut->nSeg--;
+      pStruct->nSegment--;
+    }
+  }else{
+    assert( pSeg->pgnoLast>0 );
+    fts5TrimSegments(p, pIter);
+    pLvl->nMerge = nInput;
+  }
+
+  fts5MultiIterFree(pIter);
+  fts5BufferFree(&term);
+  if( pnRem ) *pnRem -= writer.nLeafWritten;
+}
+
+/*
+** If this is not a contentless_delete=1 table, or if the 'deletemerge'
+** configuration option is set to 0, then this function always returns -1.
+** Otherwise, it searches the structure object passed as the second argument
+** for a level suitable for merging due to having a large number of
+** tombstones in the tombstone hash. If one is found, its index is returned.
+** Otherwise, if there is no suitable level, -1.
+*/
+static int fts5IndexFindDeleteMerge(Fts5Index *p, Fts5Structure *pStruct){
+  Fts5Config *pConfig = p->pConfig;
+  int iRet = -1;
+  if( pConfig->bContentlessDelete && pConfig->nDeleteMerge>0 ){
+    int ii;
+    int nBest = 0;
+
+    for(ii=0; ii<pStruct->nLevel; ii++){
+      Fts5StructureLevel *pLvl = &pStruct->aLevel[ii];
+      i64 nEntry = 0;
+      i64 nTomb = 0;
+      int iSeg;
+      for(iSeg=0; iSeg<pLvl->nSeg; iSeg++){
+        nEntry += pLvl->aSeg[iSeg].nEntry;
+        nTomb += pLvl->aSeg[iSeg].nEntryTombstone;
+      }
+      assert_nc( nEntry>0 || pLvl->nSeg==0 );
+      if( nEntry>0 ){
+        int nPercent = (nTomb * 100) / nEntry;
+        if( nPercent>=pConfig->nDeleteMerge && nPercent>nBest ){
+          iRet = ii;
+          nBest = nPercent;
+        }
+      }
+
+      /* If pLvl is already the input level to an ongoing merge, look no
+      ** further for a merge candidate. The caller should be allowed to
+      ** continue merging from pLvl first.  */
+      if( pLvl->nMerge ) break;
+    }
+  }
+  return iRet;
+}
+
+/*
+** Do up to nPg pages of automerge work on the index.
+**
+** Return true if any changes were actually made, or false otherwise.
+*/
+static int fts5IndexMerge(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Structure **ppStruct,       /* IN/OUT: Current structure of index */
+  int nPg,                        /* Pages of work to do */
+  int nMin                        /* Minimum number of segments to merge */
+){
+  int nRem = nPg;
+  int bRet = 0;
+  Fts5Structure *pStruct = *ppStruct;
+  while( nRem>0 && p->rc==SQLITE_OK ){
+    int iLvl;                   /* To iterate through levels */
+    int iBestLvl = 0;           /* Level offering the most input segments */
+    int nBest = 0;              /* Number of input segments on best level */
+
+    /* Set iBestLvl to the level to read input segments from. Or to -1 if
+    ** there is no level suitable to merge segments from.  */
+    assert( pStruct->nLevel>0 );
+    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+      Fts5StructureLevel *pLvl = &pStruct->aLevel[iLvl];
+      if( pLvl->nMerge ){
+        if( pLvl->nMerge>nBest ){
+          iBestLvl = iLvl;
+          nBest = nMin;
+        }
+        break;
+      }
+      if( pLvl->nSeg>nBest ){
+        nBest = pLvl->nSeg;
+        iBestLvl = iLvl;
+      }
+    }
+    if( nBest<nMin ){
+      iBestLvl = fts5IndexFindDeleteMerge(p, pStruct);
+    }
+
+    if( iBestLvl<0 ) break;
+    bRet = 1;
+    fts5IndexMergeLevel(p, &pStruct, iBestLvl, &nRem);
+    if( p->rc==SQLITE_OK && pStruct->aLevel[iBestLvl].nMerge==0 ){
+      fts5StructurePromote(p, iBestLvl+1, pStruct);
+    }
+
+    if( nMin==1 ) nMin = 2;
+  }
+  *ppStruct = pStruct;
+  return bRet;
+}
+
+/*
+** A total of nLeaf leaf pages of data has just been flushed to a level-0
+** segment. This function updates the write-counter accordingly and, if
+** necessary, performs incremental merge work.
+**
+** If an error occurs, set the Fts5Index.rc error code. If an error has
+** already occurred, this function is a no-op.
+*/
+static void fts5IndexAutomerge(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Structure **ppStruct,       /* IN/OUT: Current structure of index */
+  int nLeaf                       /* Number of output leaves just written */
+){
+  if( p->rc==SQLITE_OK && p->pConfig->nAutomerge>0 && ALWAYS((*ppStruct)!=0) ){
+    Fts5Structure *pStruct = *ppStruct;
+    u64 nWrite;                   /* Initial value of write-counter */
+    int nWork;                    /* Number of work-quanta to perform */
+    int nRem;                     /* Number of leaf pages left to write */
+
+    /* Update the write-counter. While doing so, set nWork. */
+    nWrite = pStruct->nWriteCounter;
+    nWork = (int)(((nWrite + nLeaf) / p->nWorkUnit) - (nWrite / p->nWorkUnit));
+    pStruct->nWriteCounter += nLeaf;
+    nRem = (int)(p->nWorkUnit * nWork * pStruct->nLevel);
+
+    fts5IndexMerge(p, ppStruct, nRem, p->pConfig->nAutomerge);
+  }
+}
+
+static void fts5IndexCrisismerge(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Structure **ppStruct        /* IN/OUT: Current structure of index */
+){
+  const int nCrisis = p->pConfig->nCrisisMerge;
+  Fts5Structure *pStruct = *ppStruct;
+  if( pStruct && pStruct->nLevel>0 ){
+    int iLvl = 0;
+    while( p->rc==SQLITE_OK && pStruct->aLevel[iLvl].nSeg>=nCrisis ){
+      fts5IndexMergeLevel(p, &pStruct, iLvl, 0);
+      assert( p->rc!=SQLITE_OK || pStruct->nLevel>(iLvl+1) );
+      fts5StructurePromote(p, iLvl+1, pStruct);
+      iLvl++;
+    }
+    *ppStruct = pStruct;
+  }
+}
+
+static int fts5IndexReturn(Fts5Index *p){
+  int rc = p->rc;
+  p->rc = SQLITE_OK;
+  return rc;
+}
+
+/*
+** Close the read-only blob handle, if it is open.
+*/
+static void sqlite3Fts5IndexCloseReader(Fts5Index *p){
+  fts5IndexCloseReader(p);
+  fts5IndexReturn(p);
+}
+
+typedef struct Fts5FlushCtx Fts5FlushCtx;
+struct Fts5FlushCtx {
+  Fts5Index *pIdx;
+  Fts5SegWriter writer;
+};
+
+/*
+** Buffer aBuf[] contains a list of varints, all small enough to fit
+** in a 32-bit integer. Return the size of the largest prefix of this
+** list nMax bytes or less in size.
+*/
+static int fts5PoslistPrefix(const u8 *aBuf, int nMax){
+  int ret;
+  u32 dummy;
+  ret = fts5GetVarint32(aBuf, dummy);
+  if( ret<nMax ){
+    while( 1 ){
+      int i = fts5GetVarint32(&aBuf[ret], dummy);
+      if( (ret + i) > nMax ) break;
+      ret += i;
+    }
+  }
+  return ret;
+}
+
+/*
+** Execute the SQL statement:
+**
+**    DELETE FROM %_idx WHERE (segid, (pgno/2)) = ($iSegid, $iPgno);
+**
+** This is used when a secure-delete operation removes the last term
+** from a segment leaf page. In that case the %_idx entry is removed
+** too. This is done to ensure that if all instances of a token are
+** removed from an fts5 database in secure-delete mode, no trace of
+** the token itself remains in the database.
+*/
+static void fts5SecureDeleteIdxEntry(
+  Fts5Index *p,                   /* FTS5 backend object */
+  int iSegid,                     /* Id of segment to delete entry for */
+  int iPgno                       /* Page number within segment */
+){
+  if( iPgno!=1 ){
+    assert( p->pConfig->iVersion==FTS5_CURRENT_VERSION_SECUREDELETE );
+    if( p->pDeleteFromIdx==0 ){
+      fts5IndexPrepareStmt(p, &p->pDeleteFromIdx, sqlite3_mprintf(
+          "DELETE FROM '%q'.'%q_idx' WHERE (segid, (pgno/2)) = (?1, ?2)",
+          p->pConfig->zDb, p->pConfig->zName
+      ));
+    }
+    if( p->rc==SQLITE_OK ){
+      sqlite3_bind_int(p->pDeleteFromIdx, 1, iSegid);
+      sqlite3_bind_int(p->pDeleteFromIdx, 2, iPgno);
+      sqlite3_step(p->pDeleteFromIdx);
+      p->rc = sqlite3_reset(p->pDeleteFromIdx);
+    }
+  }
+}
+
+/*
+** This is called when a secure-delete operation removes a position-list
+** that overflows onto segment page iPgno of segment pSeg. This function
+** rewrites node iPgno, and possibly one or more of its right-hand peers,
+** to remove this portion of the position list.
+**
+** Output variable (*pbLastInDoclist) is set to true if the position-list
+** removed is followed by a new term or the end-of-segment, or false if
+** it is followed by another rowid/position list.
+*/
+static void fts5SecureDeleteOverflow(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,
+  int iPgno,
+  int *pbLastInDoclist
+){
+  const int bDetailNone = (p->pConfig->eDetail==FTS5_DETAIL_NONE);
+  int pgno;
+  Fts5Data *pLeaf = 0;
+  assert( iPgno!=1 );
+
+  *pbLastInDoclist = 1;
+  for(pgno=iPgno; p->rc==SQLITE_OK && pgno<=pSeg->pgnoLast; pgno++){
+    i64 iRowid = FTS5_SEGMENT_ROWID(pSeg->iSegid, pgno);
+    int iNext = 0;
+    u8 *aPg = 0;
+
+    pLeaf = fts5DataRead(p, iRowid);
+    if( pLeaf==0 ) break;
+    aPg = pLeaf->p;
+
+    iNext = fts5GetU16(&aPg[0]);
+    if( iNext!=0 ){
+      *pbLastInDoclist = 0;
+    }
+    if( iNext==0 && pLeaf->szLeaf!=pLeaf->nn ){
+      fts5GetVarint32(&aPg[pLeaf->szLeaf], iNext);
+    }
+
+    if( iNext==0 ){
+      /* The page contains no terms or rowids. Replace it with an empty
+      ** page and move on to the right-hand peer.  */
+      const u8 aEmpty[] = {0x00, 0x00, 0x00, 0x04};
+      assert_nc( bDetailNone==0 || pLeaf->nn==4 );
+      if( bDetailNone==0 ) fts5DataWrite(p, iRowid, aEmpty, sizeof(aEmpty));
+      fts5DataRelease(pLeaf);
+      pLeaf = 0;
+    }else if( bDetailNone ){
+      break;
+    }else if( iNext>=pLeaf->szLeaf || pLeaf->nn<pLeaf->szLeaf || iNext<4 ){
+      p->rc = FTS5_CORRUPT;
+      break;
+    }else{
+      int nShift = iNext - 4;
+      int nPg;
+
+      int nIdx = 0;
+      u8 *aIdx = 0;
+
+      /* Unless the current page footer is 0 bytes in size (in which case
+      ** the new page footer will be as well), allocate and populate a
+      ** buffer containing the new page footer. Set stack variables aIdx
+      ** and nIdx accordingly.  */
+      if( pLeaf->nn>pLeaf->szLeaf ){
+        int iFirst = 0;
+        int i1 = pLeaf->szLeaf;
+        int i2 = 0;
+
+        i1 += fts5GetVarint32(&aPg[i1], iFirst);
+        if( iFirst<iNext ){
+          p->rc = FTS5_CORRUPT;
+          break;
+        }
+        aIdx = sqlite3Fts5MallocZero(&p->rc, (pLeaf->nn-pLeaf->szLeaf)+2);
+        if( aIdx==0 ) break;
+        i2 = sqlite3Fts5PutVarint(aIdx, iFirst-nShift);
+        if( i1<pLeaf->nn ){
+          memcpy(&aIdx[i2], &aPg[i1], pLeaf->nn-i1);
+          i2 += (pLeaf->nn-i1);
+        }
+        nIdx = i2;
+      }
+
+      /* Modify the contents of buffer aPg[]. Set nPg to the new size
+      ** in bytes. The new page is always smaller than the old.  */
+      nPg = pLeaf->szLeaf - nShift;
+      memmove(&aPg[4], &aPg[4+nShift], nPg-4);
+      fts5PutU16(&aPg[2], nPg);
+      if( fts5GetU16(&aPg[0]) ) fts5PutU16(&aPg[0], 4);
+      if( nIdx>0 ){
+        memcpy(&aPg[nPg], aIdx, nIdx);
+        nPg += nIdx;
+      }
+      sqlite3_free(aIdx);
+
+      /* Write the new page to disk and exit the loop */
+      assert( nPg>4 || fts5GetU16(aPg)==0 );
+      fts5DataWrite(p, iRowid, aPg, nPg);
+      break;
+    }
+  }
+  fts5DataRelease(pLeaf);
+}
+
+/*
+** Completely remove the entry that pSeg currently points to from
+** the database.
+*/
+static void fts5DoSecureDelete(
+  Fts5Index *p,
+  Fts5SegIter *pSeg
+){
+  const int bDetailNone = (p->pConfig->eDetail==FTS5_DETAIL_NONE);
+  int iSegid = pSeg->pSeg->iSegid;
+  u8 *aPg = pSeg->pLeaf->p;
+  int nPg = pSeg->pLeaf->nn;
+  int iPgIdx = pSeg->pLeaf->szLeaf;
+
+  u64 iDelta = 0;
+  int iNextOff = 0;
+  int iOff = 0;
+  int nIdx = 0;
+  u8 *aIdx = 0;
+  int bLastInDoclist = 0;
+  int iIdx = 0;
+  int iStart = 0;
+  int iDelKeyOff = 0;       /* Offset of deleted key, if any */
+
+  nIdx = nPg-iPgIdx;
+  aIdx = sqlite3Fts5MallocZero(&p->rc, nIdx+16);
+  if( p->rc ) return;
+  memcpy(aIdx, &aPg[iPgIdx], nIdx);
+
+  /* At this point segment iterator pSeg points to the entry
+  ** this function should remove from the b-tree segment.
+  **
+  ** In detail=full or detail=column mode, pSeg->iLeafOffset is the
+  ** offset of the first byte in the position-list for the entry to
+  ** remove. Immediately before this comes two varints that will also
+  ** need to be removed:
+  **
+  **     + the rowid or delta rowid value for the entry, and
+  **     + the size of the position list in bytes.
+  **
+  ** Or, in detail=none mode, there is a single varint prior to
+  ** pSeg->iLeafOffset - the rowid or delta rowid value.
+  **
+  ** This block sets the following variables:
+  **
+  **   iStart:
+  **     The offset of the first byte of the rowid or delta-rowid
+  **     value for the doclist entry being removed.
+  **
+  **   iDelta:
+  **     The value of the rowid or delta-rowid value for the doclist
+  **     entry being removed.
+  **
+  **   iNextOff:
+  **     The offset of the next entry following the position list
+  **     for the one being removed. If the position list for this
+  **     entry overflows onto the next leaf page, this value will be
+  **     greater than pLeaf->szLeaf.
+  */
+  {
+    int iSOP;                     /* Start-Of-Position-list */
+    if( pSeg->iLeafPgno==pSeg->iTermLeafPgno ){
+      iStart = pSeg->iTermLeafOffset;
+    }else{
+      iStart = fts5GetU16(&aPg[0]);
+    }
+
+    iSOP = iStart + fts5GetVarint(&aPg[iStart], &iDelta);
+    assert_nc( iSOP<=pSeg->iLeafOffset );
+
+    if( bDetailNone ){
+      while( iSOP<pSeg->iLeafOffset ){
+        if( aPg[iSOP]==0x00 ) iSOP++;
+        if( aPg[iSOP]==0x00 ) iSOP++;
+        iStart = iSOP;
+        iSOP = iStart + fts5GetVarint(&aPg[iStart], &iDelta);
+      }
+
+      iNextOff = iSOP;
+      if( iNextOff<pSeg->iEndofDoclist && aPg[iNextOff]==0x00 ) iNextOff++;
+      if( iNextOff<pSeg->iEndofDoclist && aPg[iNextOff]==0x00 ) iNextOff++;
+
+    }else{
+      int nPos = 0;
+      iSOP += fts5GetVarint32(&aPg[iSOP], nPos);
+      while( iSOP<pSeg->iLeafOffset ){
+        iStart = iSOP + (nPos/2);
+        iSOP = iStart + fts5GetVarint(&aPg[iStart], &iDelta);
+        iSOP += fts5GetVarint32(&aPg[iSOP], nPos);
+      }
+      assert_nc( iSOP==pSeg->iLeafOffset );
+      iNextOff = pSeg->iLeafOffset + pSeg->nPos;
+    }
+  }
+
+  iOff = iStart;
+
+  /* If the position-list for the entry being removed flows over past
+  ** the end of this page, delete the portion of the position-list on the
+  ** next page and beyond.
+  **
+  ** Set variable bLastInDoclist to true if this entry happens
+  ** to be the last rowid in the doclist for its term.  */
+  if( iNextOff>=iPgIdx ){
+    int pgno = pSeg->iLeafPgno+1;
+    fts5SecureDeleteOverflow(p, pSeg->pSeg, pgno, &bLastInDoclist);
+    iNextOff = iPgIdx;
+  }
+
+  if( pSeg->bDel==0 ){
+    if( iNextOff!=iPgIdx ){
+      /* Loop through the page-footer. If iNextOff (offset of the
+      ** entry following the one we are removing) is equal to the
+      ** offset of a key on this page, then the entry is the last
+      ** in its doclist. */
+      int iKeyOff = 0;
+      for(iIdx=0; iIdx<nIdx; /* no-op */){
+        u32 iVal = 0;
+        iIdx += fts5GetVarint32(&aIdx[iIdx], iVal);
+        iKeyOff += iVal;
+        if( iKeyOff==iNextOff ){
+          bLastInDoclist = 1;
+        }
+      }
+    }
+
+    /* If this is (a) the first rowid on a page and (b) is not followed by
+    ** another position list on the same page, set the "first-rowid" field
+    ** of the header to 0.  */
+    if( fts5GetU16(&aPg[0])==iStart && (bLastInDoclist || iNextOff==iPgIdx) ){
+      fts5PutU16(&aPg[0], 0);
+    }
+  }
+
+  if( pSeg->bDel ){
+    iOff += sqlite3Fts5PutVarint(&aPg[iOff], iDelta);
+    aPg[iOff++] = 0x01;
+  }else if( bLastInDoclist==0 ){
+    if( iNextOff!=iPgIdx ){
+      u64 iNextDelta = 0;
+      iNextOff += fts5GetVarint(&aPg[iNextOff], &iNextDelta);
+      iOff += sqlite3Fts5PutVarint(&aPg[iOff], iDelta + iNextDelta);
+    }
+  }else if(
+      pSeg->iLeafPgno==pSeg->iTermLeafPgno
+   && iStart==pSeg->iTermLeafOffset
+  ){
+    /* The entry being removed was the only position list in its
+    ** doclist. Therefore the term needs to be removed as well. */
+    int iKey = 0;
+    int iKeyOff = 0;
+
+    /* Set iKeyOff to the offset of the term that will be removed - the
+    ** last offset in the footer that is not greater than iStart. */
+    for(iIdx=0; iIdx<nIdx; iKey++){
+      u32 iVal = 0;
+      iIdx += fts5GetVarint32(&aIdx[iIdx], iVal);
+      if( (iKeyOff+iVal)>(u32)iStart ) break;
+      iKeyOff += iVal;
+    }
+    assert_nc( iKey>=1 );
+
+    /* Set iDelKeyOff to the value of the footer entry to remove from
+    ** the page. */
+    iDelKeyOff = iOff = iKeyOff;
+
+    if( iNextOff!=iPgIdx ){
+      /* This is the only position-list associated with the term, and there
+      ** is another term following it on this page. So the subsequent term
+      ** needs to be moved to replace the term associated with the entry
+      ** being removed. */
+      int nPrefix = 0;
+      int nSuffix = 0;
+      int nPrefix2 = 0;
+      int nSuffix2 = 0;
+
+      iDelKeyOff = iNextOff;
+      iNextOff += fts5GetVarint32(&aPg[iNextOff], nPrefix2);
+      iNextOff += fts5GetVarint32(&aPg[iNextOff], nSuffix2);
+
+      if( iKey!=1 ){
+        iKeyOff += fts5GetVarint32(&aPg[iKeyOff], nPrefix);
+      }
+      iKeyOff += fts5GetVarint32(&aPg[iKeyOff], nSuffix);
+
+      nPrefix = MIN(nPrefix, nPrefix2);
+      nSuffix = (nPrefix2 + nSuffix2) - nPrefix;
+
+      if( (iKeyOff+nSuffix)>iPgIdx || (iNextOff+nSuffix2)>iPgIdx ){
+        p->rc = FTS5_CORRUPT;
+      }else{
+        if( iKey!=1 ){
+          iOff += sqlite3Fts5PutVarint(&aPg[iOff], nPrefix);
+        }
+        iOff += sqlite3Fts5PutVarint(&aPg[iOff], nSuffix);
+        if( nPrefix2>pSeg->term.n ){
+          p->rc = FTS5_CORRUPT;
+        }else if( nPrefix2>nPrefix ){
+          memcpy(&aPg[iOff], &pSeg->term.p[nPrefix], nPrefix2-nPrefix);
+          iOff += (nPrefix2-nPrefix);
+        }
+        memmove(&aPg[iOff], &aPg[iNextOff], nSuffix2);
+        iOff += nSuffix2;
+        iNextOff += nSuffix2;
+      }
+    }
+  }else if( iStart==4 ){
+    int iPgno;
+
+    assert_nc( pSeg->iLeafPgno>pSeg->iTermLeafPgno );
+    /* The entry being removed may be the only position list in
+    ** its doclist. */
+    for(iPgno=pSeg->iLeafPgno-1; iPgno>pSeg->iTermLeafPgno; iPgno-- ){
+      Fts5Data *pPg = fts5DataRead(p, FTS5_SEGMENT_ROWID(iSegid, iPgno));
+      int bEmpty = (pPg && pPg->nn==4);
+      fts5DataRelease(pPg);
+      if( bEmpty==0 ) break;
+    }
+
+    if( iPgno==pSeg->iTermLeafPgno ){
+      i64 iId = FTS5_SEGMENT_ROWID(iSegid, pSeg->iTermLeafPgno);
+      Fts5Data *pTerm = fts5DataRead(p, iId);
+      if( pTerm && pTerm->szLeaf==pSeg->iTermLeafOffset ){
+        u8 *aTermIdx = &pTerm->p[pTerm->szLeaf];
+        int nTermIdx = pTerm->nn - pTerm->szLeaf;
+        int iTermIdx = 0;
+        int iTermOff = 0;
+
+        while( 1 ){
+          u32 iVal = 0;
+          int nByte = fts5GetVarint32(&aTermIdx[iTermIdx], iVal);
+          iTermOff += iVal;
+          if( (iTermIdx+nByte)>=nTermIdx ) break;
+          iTermIdx += nByte;
+        }
+        nTermIdx = iTermIdx;
+
+        memmove(&pTerm->p[iTermOff], &pTerm->p[pTerm->szLeaf], nTermIdx);
+        fts5PutU16(&pTerm->p[2], iTermOff);
+
+        fts5DataWrite(p, iId, pTerm->p, iTermOff+nTermIdx);
+        if( nTermIdx==0 ){
+          fts5SecureDeleteIdxEntry(p, iSegid, pSeg->iTermLeafPgno);
+        }
+      }
+      fts5DataRelease(pTerm);
+    }
+  }
+
+  /* Assuming no error has occurred, this block does final edits to the
+  ** leaf page before writing it back to disk. Input variables are:
+  **
+  **   nPg: Total initial size of leaf page.
+  **   iPgIdx: Initial offset of page footer.
+  **
+  **   iOff: Offset to move data to
+  **   iNextOff: Offset to move data from
+  */
+  if( p->rc==SQLITE_OK ){
+    const int nMove = nPg - iNextOff;     /* Number of bytes to move */
+    int nShift = iNextOff - iOff;         /* Distance to move them */
+
+    int iPrevKeyOut = 0;
+    int iKeyIn = 0;
+
+    memmove(&aPg[iOff], &aPg[iNextOff], nMove);
+    iPgIdx -= nShift;
+    nPg = iPgIdx;
+    fts5PutU16(&aPg[2], iPgIdx);
+
+    for(iIdx=0; iIdx<nIdx; /* no-op */){
+      u32 iVal = 0;
+      iIdx += fts5GetVarint32(&aIdx[iIdx], iVal);
+      iKeyIn += iVal;
+      if( iKeyIn!=iDelKeyOff ){
+        int iKeyOut = (iKeyIn - (iKeyIn>iOff ? nShift : 0));
+        nPg += sqlite3Fts5PutVarint(&aPg[nPg], iKeyOut - iPrevKeyOut);
+        iPrevKeyOut = iKeyOut;
+      }
+    }
+
+    if( iPgIdx==nPg && nIdx>0 && pSeg->iLeafPgno!=1 ){
+      fts5SecureDeleteIdxEntry(p, iSegid, pSeg->iLeafPgno);
+    }
+
+    assert_nc( nPg>4 || fts5GetU16(aPg)==0 );
+    fts5DataWrite(p, FTS5_SEGMENT_ROWID(iSegid,pSeg->iLeafPgno), aPg, nPg);
+  }
+  sqlite3_free(aIdx);
+}
+
+/*
+** This is called as part of flushing a delete to disk in 'secure-delete'
+** mode. It edits the segments within the database described by argument
+** pStruct to remove the entries for term zTerm, rowid iRowid.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** has occurred. Any error code is also stored in the Fts5Index handle.
+*/
+static int fts5FlushSecureDelete(
+  Fts5Index *p,
+  Fts5Structure *pStruct,
+  const char *zTerm,
+  int nTerm,
+  i64 iRowid
+){
+  const int f = FTS5INDEX_QUERY_SKIPHASH;
+  Fts5Iter *pIter = 0;            /* Used to find term instance */
+
+  /* If the version number has not been set to SECUREDELETE, do so now. */
+  if( p->pConfig->iVersion!=FTS5_CURRENT_VERSION_SECUREDELETE ){
+    Fts5Config *pConfig = p->pConfig;
+    sqlite3_stmt *pStmt = 0;
+    fts5IndexPrepareStmt(p, &pStmt, sqlite3_mprintf(
+          "REPLACE INTO %Q.'%q_config' VALUES ('version', %d)",
+          pConfig->zDb, pConfig->zName, FTS5_CURRENT_VERSION_SECUREDELETE
+    ));
+    if( p->rc==SQLITE_OK ){
+      int rc;
+      sqlite3_step(pStmt);
+      rc = sqlite3_finalize(pStmt);
+      if( p->rc==SQLITE_OK ) p->rc = rc;
+      pConfig->iCookie++;
+      pConfig->iVersion = FTS5_CURRENT_VERSION_SECUREDELETE;
+    }
+  }
+
+  fts5MultiIterNew(p, pStruct, f, 0, (const u8*)zTerm, nTerm, -1, 0, &pIter);
+  if( fts5MultiIterEof(p, pIter)==0 ){
+    i64 iThis = fts5MultiIterRowid(pIter);
+    if( iThis<iRowid ){
+      fts5MultiIterNextFrom(p, pIter, iRowid);
+    }
+
+    if( p->rc==SQLITE_OK
+     && fts5MultiIterEof(p, pIter)==0
+     && iRowid==fts5MultiIterRowid(pIter)
+    ){
+      Fts5SegIter *pSeg = &pIter->aSeg[pIter->aFirst[1].iFirst];
+      fts5DoSecureDelete(p, pSeg);
+    }
+  }
+
+  fts5MultiIterFree(pIter);
+  return p->rc;
+}
+
+
+/*
+** Flush the contents of in-memory hash table iHash to a new level-0
+** segment on disk. Also update the corresponding structure record.
+**
+** If an error occurs, set the Fts5Index.rc error code. If an error has
+** already occurred, this function is a no-op.
+*/
+static void fts5FlushOneHash(Fts5Index *p){
+  Fts5Hash *pHash = p->pHash;
+  Fts5Structure *pStruct;
+  int iSegid;
+  int pgnoLast = 0;                 /* Last leaf page number in segment */
+
+  /* Obtain a reference to the index structure and allocate a new segment-id
+  ** for the new level-0 segment.  */
+  pStruct = fts5StructureRead(p);
+  fts5StructureInvalidate(p);
+
+  if( sqlite3Fts5HashIsEmpty(pHash)==0 ){
+    iSegid = fts5AllocateSegid(p, pStruct);
+    if( iSegid ){
+      const int pgsz = p->pConfig->pgsz;
+      int eDetail = p->pConfig->eDetail;
+      int bSecureDelete = p->pConfig->bSecureDelete;
+      Fts5StructureSegment *pSeg; /* New segment within pStruct */
+      Fts5Buffer *pBuf;           /* Buffer in which to assemble leaf page */
+      Fts5Buffer *pPgidx;         /* Buffer in which to assemble pgidx */
+
+      Fts5SegWriter writer;
+      fts5WriteInit(p, &writer, iSegid);
+
+      pBuf = &writer.writer.buf;
+      pPgidx = &writer.writer.pgidx;
+
+      /* fts5WriteInit() should have initialized the buffers to (most likely)
+      ** the maximum space required. */
+      assert( p->rc || pBuf->nSpace>=(pgsz + FTS5_DATA_PADDING) );
+      assert( p->rc || pPgidx->nSpace>=(pgsz + FTS5_DATA_PADDING) );
+
+      /* Begin scanning through hash table entries. This loop runs once for each
+      ** term/doclist currently stored within the hash table. */
+      if( p->rc==SQLITE_OK ){
+        p->rc = sqlite3Fts5HashScanInit(pHash, 0, 0);
+      }
+      while( p->rc==SQLITE_OK && 0==sqlite3Fts5HashScanEof(pHash) ){
+        const char *zTerm;        /* Buffer containing term */
+        int nTerm;                /* Size of zTerm in bytes */
+        const u8 *pDoclist;       /* Pointer to doclist for this term */
+        int nDoclist;             /* Size of doclist in bytes */
+
+        /* Get the term and doclist for this entry. */
+        sqlite3Fts5HashScanEntry(pHash, &zTerm, &nTerm, &pDoclist, &nDoclist);
+        if( bSecureDelete==0 ){
+          fts5WriteAppendTerm(p, &writer, nTerm, (const u8*)zTerm);
+          if( p->rc!=SQLITE_OK ) break;
+          assert( writer.bFirstRowidInPage==0 );
+        }
+
+        if( !bSecureDelete && pgsz>=(pBuf->n + pPgidx->n + nDoclist + 1) ){
+          /* The entire doclist will fit on the current leaf. */
+          fts5BufferSafeAppendBlob(pBuf, pDoclist, nDoclist);
+        }else{
+          int bTermWritten = !bSecureDelete;
+          i64 iRowid = 0;
+          i64 iPrev = 0;
+          int iOff = 0;
+
+          /* The entire doclist will not fit on this leaf. The following
+          ** loop iterates through the poslists that make up the current
+          ** doclist.  */
+          while( p->rc==SQLITE_OK && iOff<nDoclist ){
+            u64 iDelta = 0;
+            iOff += fts5GetVarint(&pDoclist[iOff], &iDelta);
+            iRowid += iDelta;
+
+            /* If in secure delete mode, and if this entry in the poslist is
+            ** in fact a delete, then edit the existing segments directly
+            ** using fts5FlushSecureDelete().  */
+            if( bSecureDelete ){
+              if( eDetail==FTS5_DETAIL_NONE ){
+                if( iOff<nDoclist && pDoclist[iOff]==0x00
+                 && !fts5FlushSecureDelete(p, pStruct, zTerm, nTerm, iRowid)
+                ){
+                  iOff++;
+                  if( iOff<nDoclist && pDoclist[iOff]==0x00 ){
+                    iOff++;
+                    nDoclist = 0;
+                  }else{
+                    continue;
+                  }
+                }
+              }else if( (pDoclist[iOff] & 0x01)
+                && !fts5FlushSecureDelete(p, pStruct, zTerm, nTerm, iRowid)
+              ){
+                if( p->rc!=SQLITE_OK || pDoclist[iOff]==0x01 ){
+                  iOff++;
+                  continue;
+                }
+              }
+            }
+
+            if( p->rc==SQLITE_OK && bTermWritten==0 ){
+              fts5WriteAppendTerm(p, &writer, nTerm, (const u8*)zTerm);
+              bTermWritten = 1;
+              assert( p->rc!=SQLITE_OK || writer.bFirstRowidInPage==0 );
+            }
+
+            if( writer.bFirstRowidInPage ){
+              fts5PutU16(&pBuf->p[0], (u16)pBuf->n);   /* first rowid on page */
+              pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], iRowid);
+              writer.bFirstRowidInPage = 0;
+              fts5WriteDlidxAppend(p, &writer, iRowid);
+            }else{
+              u64 iRowidDelta = (u64)iRowid - (u64)iPrev;
+              pBuf->n += sqlite3Fts5PutVarint(&pBuf->p[pBuf->n], iRowidDelta);
+            }
+            if( p->rc!=SQLITE_OK ) break;
+            assert( pBuf->n<=pBuf->nSpace );
+            iPrev = iRowid;
+
+            if( eDetail==FTS5_DETAIL_NONE ){
+              if( iOff<nDoclist && pDoclist[iOff]==0 ){
+                pBuf->p[pBuf->n++] = 0;
+                iOff++;
+                if( iOff<nDoclist && pDoclist[iOff]==0 ){
+                  pBuf->p[pBuf->n++] = 0;
+                  iOff++;
+                }
+              }
+              if( (pBuf->n + pPgidx->n)>=pgsz ){
+                fts5WriteFlushLeaf(p, &writer);
+              }
+            }else{
+              int bDel = 0;
+              int nPos = 0;
+              int nCopy = fts5GetPoslistSize(&pDoclist[iOff], &nPos, &bDel);
+              if( bDel && bSecureDelete ){
+                fts5BufferAppendVarint(&p->rc, pBuf, nPos*2);
+                iOff += nCopy;
+                nCopy = nPos;
+              }else{
+                nCopy += nPos;
+              }
+              if( (pBuf->n + pPgidx->n + nCopy) <= pgsz ){
+                /* The entire poslist will fit on the current leaf. So copy
+                ** it in one go. */
+                fts5BufferSafeAppendBlob(pBuf, &pDoclist[iOff], nCopy);
+              }else{
+                /* The entire poslist will not fit on this leaf. So it needs
+                ** to be broken into sections. The only qualification being
+                ** that each varint must be stored contiguously.  */
+                const u8 *pPoslist = &pDoclist[iOff];
+                int iPos = 0;
+                while( p->rc==SQLITE_OK ){
+                  int nSpace = pgsz - pBuf->n - pPgidx->n;
+                  int n = 0;
+                  if( (nCopy - iPos)<=nSpace ){
+                    n = nCopy - iPos;
+                  }else{
+                    n = fts5PoslistPrefix(&pPoslist[iPos], nSpace);
+                  }
+                  assert( n>0 );
+                  fts5BufferSafeAppendBlob(pBuf, &pPoslist[iPos], n);
+                  iPos += n;
+                  if( (pBuf->n + pPgidx->n)>=pgsz ){
+                    fts5WriteFlushLeaf(p, &writer);
+                  }
+                  if( iPos>=nCopy ) break;
+                }
+              }
+              iOff += nCopy;
+            }
+          }
+        }
+
+        /* TODO2: Doclist terminator written here. */
+        /* pBuf->p[pBuf->n++] = '\0'; */
+        assert( pBuf->n<=pBuf->nSpace );
+        if( p->rc==SQLITE_OK ) sqlite3Fts5HashScanNext(pHash);
+      }
+      fts5WriteFinish(p, &writer, &pgnoLast);
+
+      assert( p->rc!=SQLITE_OK || bSecureDelete || pgnoLast>0 );
+      if( pgnoLast>0 ){
+        /* Update the Fts5Structure. It is written back to the database by the
+        ** fts5StructureRelease() call below.  */
+        if( pStruct->nLevel==0 ){
+          fts5StructureAddLevel(&p->rc, &pStruct);
+        }
+        fts5StructureExtendLevel(&p->rc, pStruct, 0, 1, 0);
+        if( p->rc==SQLITE_OK ){
+          pSeg = &pStruct->aLevel[0].aSeg[ pStruct->aLevel[0].nSeg++ ];
+          pSeg->iSegid = iSegid;
+          pSeg->pgnoFirst = 1;
+          pSeg->pgnoLast = pgnoLast;
+          if( pStruct->nOriginCntr>0 ){
+            pSeg->iOrigin1 = pStruct->nOriginCntr;
+            pSeg->iOrigin2 = pStruct->nOriginCntr;
+            pSeg->nEntry = p->nPendingRow;
+            pStruct->nOriginCntr++;
+          }
+          pStruct->nSegment++;
+        }
+        fts5StructurePromote(p, 0, pStruct);
+      }
+    }
+  }
+
+  fts5IndexAutomerge(p, &pStruct, pgnoLast + p->nContentlessDelete);
+  fts5IndexCrisismerge(p, &pStruct);
+  fts5StructureWrite(p, pStruct);
+  fts5StructureRelease(pStruct);
+}
+
+/*
+** Flush any data stored in the in-memory hash tables to the database.
+*/
+static void fts5IndexFlush(Fts5Index *p){
+  /* Unless it is empty, flush the hash table to disk */
+  if( p->flushRc ){
+    p->rc = p->flushRc;
+    return;
+  }
+  if( p->nPendingData || p->nContentlessDelete ){
+    assert( p->pHash );
+    fts5FlushOneHash(p);
+    if( p->rc==SQLITE_OK ){
+      sqlite3Fts5HashClear(p->pHash);
+      p->nPendingData = 0;
+      p->nPendingRow = 0;
+      p->nContentlessDelete = 0;
+    }else if( p->nPendingData || p->nContentlessDelete ){
+      p->flushRc = p->rc;
+    }
+  }
+}
+
+static Fts5Structure *fts5IndexOptimizeStruct(
+  Fts5Index *p,
+  Fts5Structure *pStruct
+){
+  Fts5Structure *pNew = 0;
+  sqlite3_int64 nByte = sizeof(Fts5Structure);
+  int nSeg = pStruct->nSegment;
+  int i;
+
+  /* Figure out if this structure requires optimization. A structure does
+  ** not require optimization if either:
+  **
+  **  1. it consists of fewer than two segments, or
+  **  2. all segments are on the same level, or
+  **  3. all segments except one are currently inputs to a merge operation.
+  **
+  ** In the first case, if there are no tombstone hash pages, return NULL. In
+  ** the second, increment the ref-count on *pStruct and return a copy of the
+  ** pointer to it.
+  */
+  if( nSeg==0 ) return 0;
+  for(i=0; i<pStruct->nLevel; i++){
+    int nThis = pStruct->aLevel[i].nSeg;
+    int nMerge = pStruct->aLevel[i].nMerge;
+    if( nThis>0 && (nThis==nSeg || (nThis==nSeg-1 && nMerge==nThis)) ){
+      if( nSeg==1 && nThis==1 && pStruct->aLevel[i].aSeg[0].nPgTombstone==0 ){
+        return 0;
+      }
+      fts5StructureRef(pStruct);
+      return pStruct;
+    }
+    assert( pStruct->aLevel[i].nMerge<=nThis );
+  }
+
+  nByte += (pStruct->nLevel+1) * sizeof(Fts5StructureLevel);
+  pNew = (Fts5Structure*)sqlite3Fts5MallocZero(&p->rc, nByte);
+
+  if( pNew ){
+    Fts5StructureLevel *pLvl;
+    nByte = nSeg * sizeof(Fts5StructureSegment);
+    pNew->nLevel = MIN(pStruct->nLevel+1, FTS5_MAX_LEVEL);
+    pNew->nRef = 1;
+    pNew->nWriteCounter = pStruct->nWriteCounter;
+    pNew->nOriginCntr = pStruct->nOriginCntr;
+    pLvl = &pNew->aLevel[pNew->nLevel-1];
+    pLvl->aSeg = (Fts5StructureSegment*)sqlite3Fts5MallocZero(&p->rc, nByte);
+    if( pLvl->aSeg ){
+      int iLvl, iSeg;
+      int iSegOut = 0;
+      /* Iterate through all segments, from oldest to newest. Add them to
+      ** the new Fts5Level object so that pLvl->aSeg[0] is the oldest
+      ** segment in the data structure.  */
+      for(iLvl=pStruct->nLevel-1; iLvl>=0; iLvl--){
+        for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
+          pLvl->aSeg[iSegOut] = pStruct->aLevel[iLvl].aSeg[iSeg];
+          iSegOut++;
+        }
+      }
+      pNew->nSegment = pLvl->nSeg = nSeg;
+    }else{
+      sqlite3_free(pNew);
+      pNew = 0;
+    }
+  }
+
+  return pNew;
+}
+
+static int sqlite3Fts5IndexOptimize(Fts5Index *p){
+  Fts5Structure *pStruct;
+  Fts5Structure *pNew = 0;
+
+  assert( p->rc==SQLITE_OK );
+  fts5IndexFlush(p);
+  assert( p->rc!=SQLITE_OK || p->nContentlessDelete==0 );
+  pStruct = fts5StructureRead(p);
+  assert( p->rc!=SQLITE_OK || pStruct!=0 );
+  fts5StructureInvalidate(p);
+
+  if( pStruct ){
+    pNew = fts5IndexOptimizeStruct(p, pStruct);
+  }
+  fts5StructureRelease(pStruct);
+
+  assert( pNew==0 || pNew->nSegment>0 );
+  if( pNew ){
+    int iLvl;
+    for(iLvl=0; pNew->aLevel[iLvl].nSeg==0; iLvl++){}
+    while( p->rc==SQLITE_OK && pNew->aLevel[iLvl].nSeg>0 ){
+      int nRem = FTS5_OPT_WORK_UNIT;
+      fts5IndexMergeLevel(p, &pNew, iLvl, &nRem);
+    }
+
+    fts5StructureWrite(p, pNew);
+    fts5StructureRelease(pNew);
+  }
+
+  return fts5IndexReturn(p);
+}
+
+/*
+** This is called to implement the special "VALUES('merge', $nMerge)"
+** INSERT command.
+*/
+static int sqlite3Fts5IndexMerge(Fts5Index *p, int nMerge){
+  Fts5Structure *pStruct = 0;
+
+  fts5IndexFlush(p);
+  pStruct = fts5StructureRead(p);
+  if( pStruct ){
+    int nMin = p->pConfig->nUsermerge;
+    fts5StructureInvalidate(p);
+    if( nMerge<0 ){
+      Fts5Structure *pNew = fts5IndexOptimizeStruct(p, pStruct);
+      fts5StructureRelease(pStruct);
+      pStruct = pNew;
+      nMin = 1;
+      nMerge = nMerge*-1;
+    }
+    if( pStruct && pStruct->nLevel ){
+      if( fts5IndexMerge(p, &pStruct, nMerge, nMin) ){
+        fts5StructureWrite(p, pStruct);
+      }
+    }
+    fts5StructureRelease(pStruct);
+  }
+  return fts5IndexReturn(p);
+}
+
+static void fts5AppendRowid(
+  Fts5Index *p,
+  u64 iDelta,
+  Fts5Iter *pUnused,
+  Fts5Buffer *pBuf
+){
+  UNUSED_PARAM(pUnused);
+  fts5BufferAppendVarint(&p->rc, pBuf, iDelta);
+}
+
+static void fts5AppendPoslist(
+  Fts5Index *p,
+  u64 iDelta,
+  Fts5Iter *pMulti,
+  Fts5Buffer *pBuf
+){
+  int nData = pMulti->base.nData;
+  int nByte = nData + 9 + 9 + FTS5_DATA_ZERO_PADDING;
+  assert( nData>0 );
+  if( p->rc==SQLITE_OK && 0==fts5BufferGrow(&p->rc, pBuf, nByte) ){
+    fts5BufferSafeAppendVarint(pBuf, iDelta);
+    fts5BufferSafeAppendVarint(pBuf, nData*2);
+    fts5BufferSafeAppendBlob(pBuf, pMulti->base.pData, nData);
+    memset(&pBuf->p[pBuf->n], 0, FTS5_DATA_ZERO_PADDING);
+  }
+}
+
+
+static void fts5DoclistIterNext(Fts5DoclistIter *pIter){
+  u8 *p = pIter->aPoslist + pIter->nSize + pIter->nPoslist;
+
+  assert( pIter->aPoslist || (p==0 && pIter->aPoslist==0) );
+  if( p>=pIter->aEof ){
+    pIter->aPoslist = 0;
+  }else{
+    i64 iDelta;
+
+    p += fts5GetVarint(p, (u64*)&iDelta);
+    pIter->iRowid += iDelta;
+
+    /* Read position list size */
+    if( p[0] & 0x80 ){
+      int nPos;
+      pIter->nSize = fts5GetVarint32(p, nPos);
+      pIter->nPoslist = (nPos>>1);
+    }else{
+      pIter->nPoslist = ((int)(p[0])) >> 1;
+      pIter->nSize = 1;
+    }
+
+    pIter->aPoslist = p;
+    if( &pIter->aPoslist[pIter->nPoslist]>pIter->aEof ){
+      pIter->aPoslist = 0;
+    }
+  }
+}
+
+static void fts5DoclistIterInit(
+  Fts5Buffer *pBuf,
+  Fts5DoclistIter *pIter
+){
+  memset(pIter, 0, sizeof(*pIter));
+  if( pBuf->n>0 ){
+    pIter->aPoslist = pBuf->p;
+    pIter->aEof = &pBuf->p[pBuf->n];
+    fts5DoclistIterNext(pIter);
+  }
+}
+
+#if 0
+/*
+** Append a doclist to buffer pBuf.
+**
+** This function assumes that space within the buffer has already been
+** allocated.
+*/
+static void fts5MergeAppendDocid(
+  Fts5Buffer *pBuf,               /* Buffer to write to */
+  i64 *piLastRowid,               /* IN/OUT: Previous rowid written (if any) */
+  i64 iRowid                      /* Rowid to append */
+){
+  assert( pBuf->n!=0 || (*piLastRowid)==0 );
+  fts5BufferSafeAppendVarint(pBuf, iRowid - *piLastRowid);
+  *piLastRowid = iRowid;
+}
+#endif
+
+#define fts5MergeAppendDocid(pBuf, iLastRowid, iRowid) {                 \
+  assert( (pBuf)->n!=0 || (iLastRowid)==0 );                             \
+  fts5BufferSafeAppendVarint((pBuf), (u64)(iRowid) - (u64)(iLastRowid)); \
+  (iLastRowid) = (iRowid);                                               \
+}
+
+/*
+** Swap the contents of buffer *p1 with that of *p2.
+*/
+static void fts5BufferSwap(Fts5Buffer *p1, Fts5Buffer *p2){
+  Fts5Buffer tmp = *p1;
+  *p1 = *p2;
+  *p2 = tmp;
+}
+
+static void fts5NextRowid(Fts5Buffer *pBuf, int *piOff, i64 *piRowid){
+  int i = *piOff;
+  if( i>=pBuf->n ){
+    *piOff = -1;
+  }else{
+    u64 iVal;
+    *piOff = i + sqlite3Fts5GetVarint(&pBuf->p[i], &iVal);
+    *piRowid += iVal;
+  }
+}
+
+/*
+** This is the equivalent of fts5MergePrefixLists() for detail=none mode.
+** In this case the buffers consist of a delta-encoded list of rowids only.
+*/
+static void fts5MergeRowidLists(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Buffer *p1,                 /* First list to merge */
+  int nBuf,                       /* Number of entries in apBuf[] */
+  Fts5Buffer *aBuf                /* Array of other lists to merge into p1 */
+){
+  int i1 = 0;
+  int i2 = 0;
+  i64 iRowid1 = 0;
+  i64 iRowid2 = 0;
+  i64 iOut = 0;
+  Fts5Buffer *p2 = &aBuf[0];
+  Fts5Buffer out;
+
+  (void)nBuf;
+  memset(&out, 0, sizeof(out));
+  assert( nBuf==1 );
+  sqlite3Fts5BufferSize(&p->rc, &out, p1->n + p2->n);
+  if( p->rc ) return;
+
+  fts5NextRowid(p1, &i1, &iRowid1);
+  fts5NextRowid(p2, &i2, &iRowid2);
+  while( i1>=0 || i2>=0 ){
+    if( i1>=0 && (i2<0 || iRowid1<iRowid2) ){
+      assert( iOut==0 || iRowid1>iOut );
+      fts5BufferSafeAppendVarint(&out, iRowid1 - iOut);
+      iOut = iRowid1;
+      fts5NextRowid(p1, &i1, &iRowid1);
+    }else{
+      assert( iOut==0 || iRowid2>iOut );
+      fts5BufferSafeAppendVarint(&out, iRowid2 - iOut);
+      iOut = iRowid2;
+      if( i1>=0 && iRowid1==iRowid2 ){
+        fts5NextRowid(p1, &i1, &iRowid1);
+      }
+      fts5NextRowid(p2, &i2, &iRowid2);
+    }
+  }
+
+  fts5BufferSwap(&out, p1);
+  fts5BufferFree(&out);
+}
+
+typedef struct PrefixMerger PrefixMerger;
+struct PrefixMerger {
+  Fts5DoclistIter iter;           /* Doclist iterator */
+  i64 iPos;                       /* For iterating through a position list */
+  int iOff;
+  u8 *aPos;
+  PrefixMerger *pNext;            /* Next in docid/poslist order */
+};
+
+static void fts5PrefixMergerInsertByRowid(
+  PrefixMerger **ppHead,
+  PrefixMerger *p
+){
+  if( p->iter.aPoslist ){
+    PrefixMerger **pp = ppHead;
+    while( *pp && p->iter.iRowid>(*pp)->iter.iRowid ){
+      pp = &(*pp)->pNext;
+    }
+    p->pNext = *pp;
+    *pp = p;
+  }
+}
+
+static void fts5PrefixMergerInsertByPosition(
+  PrefixMerger **ppHead,
+  PrefixMerger *p
+){
+  if( p->iPos>=0 ){
+    PrefixMerger **pp = ppHead;
+    while( *pp && p->iPos>(*pp)->iPos ){
+      pp = &(*pp)->pNext;
+    }
+    p->pNext = *pp;
+    *pp = p;
+  }
+}
+
+
+/*
+** Array aBuf[] contains nBuf doclists. These are all merged in with the
+** doclist in buffer p1.
+*/
+static void fts5MergePrefixLists(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5Buffer *p1,                 /* First list to merge */
+  int nBuf,                       /* Number of buffers in array aBuf[] */
+  Fts5Buffer *aBuf                /* Other lists to merge in */
+){
+#define fts5PrefixMergerNextPosition(p) \
+  sqlite3Fts5PoslistNext64((p)->aPos,(p)->iter.nPoslist,&(p)->iOff,&(p)->iPos)
+#define FTS5_MERGE_NLIST 16
+  PrefixMerger aMerger[FTS5_MERGE_NLIST];
+  PrefixMerger *pHead = 0;
+  int i;
+  int nOut = 0;
+  Fts5Buffer out = {0, 0, 0};
+  Fts5Buffer tmp = {0, 0, 0};
+  i64 iLastRowid = 0;
+
+  /* Initialize a doclist-iterator for each input buffer. Arrange them in
+  ** a linked-list starting at pHead in ascending order of rowid. Avoid
+  ** linking any iterators already at EOF into the linked list at all. */
+  assert( nBuf+1<=(int)(sizeof(aMerger)/sizeof(aMerger[0])) );
+  memset(aMerger, 0, sizeof(PrefixMerger)*(nBuf+1));
+  pHead = &aMerger[nBuf];
+  fts5DoclistIterInit(p1, &pHead->iter);
+  for(i=0; i<nBuf; i++){
+    fts5DoclistIterInit(&aBuf[i], &aMerger[i].iter);
+    fts5PrefixMergerInsertByRowid(&pHead, &aMerger[i]);
+    nOut += aBuf[i].n;
+  }
+  if( nOut==0 ) return;
+  nOut += p1->n + 9 + 10*nBuf;
+
+  /* The maximum size of the output is equal to the sum of the
+  ** input sizes + 1 varint (9 bytes). The extra varint is because if the
+  ** first rowid in one input is a large negative number, and the first in
+  ** the other a non-negative number, the delta for the non-negative
+  ** number will be larger on disk than the literal integer value
+  ** was.
+  **
+  ** Or, if the input position-lists are corrupt, then the output might
+  ** include up to (nBuf+1) extra 10-byte positions created by interpreting -1
+  ** (the value PoslistNext64() uses for EOF) as a position and appending
+  ** it to the output. This can happen at most once for each input
+  ** position-list, hence (nBuf+1) 10 byte paddings.  */
+  if( sqlite3Fts5BufferSize(&p->rc, &out, nOut) ) return;
+
+  while( pHead ){
+    fts5MergeAppendDocid(&out, iLastRowid, pHead->iter.iRowid);
+
+    if( pHead->pNext && iLastRowid==pHead->pNext->iter.iRowid ){
+      /* Merge data from two or more poslists */
+      i64 iPrev = 0;
+      int nTmp = FTS5_DATA_ZERO_PADDING;
+      int nMerge = 0;
+      PrefixMerger *pSave = pHead;
+      PrefixMerger *pThis = 0;
+      int nTail = 0;
+
+      pHead = 0;
+      while( pSave && pSave->iter.iRowid==iLastRowid ){
+        PrefixMerger *pNext = pSave->pNext;
+        pSave->iOff = 0;
+        pSave->iPos = 0;
+        pSave->aPos = &pSave->iter.aPoslist[pSave->iter.nSize];
+        fts5PrefixMergerNextPosition(pSave);
+        nTmp += pSave->iter.nPoslist + 10;
+        nMerge++;
+        fts5PrefixMergerInsertByPosition(&pHead, pSave);
+        pSave = pNext;
+      }
+
+      if( pHead==0 || pHead->pNext==0 ){
+        p->rc = FTS5_CORRUPT;
+        break;
+      }
+
+      /* See the earlier comment in this function for an explanation of why
+      ** corrupt input position lists might cause the output to consume
+      ** at most nMerge*10 bytes of unexpected space. */
+      if( sqlite3Fts5BufferSize(&p->rc, &tmp, nTmp+nMerge*10) ){
+        break;
+      }
+      fts5BufferZero(&tmp);
+
+      pThis = pHead;
+      pHead = pThis->pNext;
+      sqlite3Fts5PoslistSafeAppend(&tmp, &iPrev, pThis->iPos);
+      fts5PrefixMergerNextPosition(pThis);
+      fts5PrefixMergerInsertByPosition(&pHead, pThis);
+
+      while( pHead->pNext ){
+        pThis = pHead;
+        if( pThis->iPos!=iPrev ){
+          sqlite3Fts5PoslistSafeAppend(&tmp, &iPrev, pThis->iPos);
+        }
+        fts5PrefixMergerNextPosition(pThis);
+        pHead = pThis->pNext;
+        fts5PrefixMergerInsertByPosition(&pHead, pThis);
+      }
+
+      if( pHead->iPos!=iPrev ){
+        sqlite3Fts5PoslistSafeAppend(&tmp, &iPrev, pHead->iPos);
+      }
+      nTail = pHead->iter.nPoslist - pHead->iOff;
+
+      /* WRITEPOSLISTSIZE */
+      assert_nc( tmp.n+nTail<=nTmp );
+      assert( tmp.n+nTail<=nTmp+nMerge*10 );
+      if( tmp.n+nTail>nTmp-FTS5_DATA_ZERO_PADDING ){
+        if( p->rc==SQLITE_OK ) p->rc = FTS5_CORRUPT;
+        break;
+      }
+      fts5BufferSafeAppendVarint(&out, (tmp.n+nTail) * 2);
+      fts5BufferSafeAppendBlob(&out, tmp.p, tmp.n);
+      if( nTail>0 ){
+        fts5BufferSafeAppendBlob(&out, &pHead->aPos[pHead->iOff], nTail);
+      }
+
+      pHead = pSave;
+      for(i=0; i<nBuf+1; i++){
+        PrefixMerger *pX = &aMerger[i];
+        if( pX->iter.aPoslist && pX->iter.iRowid==iLastRowid ){
+          fts5DoclistIterNext(&pX->iter);
+          fts5PrefixMergerInsertByRowid(&pHead, pX);
+        }
+      }
+
+    }else{
+      /* Copy poslist from pHead to output */
+      PrefixMerger *pThis = pHead;
+      Fts5DoclistIter *pI = &pThis->iter;
+      fts5BufferSafeAppendBlob(&out, pI->aPoslist, pI->nPoslist+pI->nSize);
+      fts5DoclistIterNext(pI);
+      pHead = pThis->pNext;
+      fts5PrefixMergerInsertByRowid(&pHead, pThis);
+    }
+  }
+
+  fts5BufferFree(p1);
+  fts5BufferFree(&tmp);
+  memset(&out.p[out.n], 0, FTS5_DATA_ZERO_PADDING);
+  *p1 = out;
+}
+
+
+/*
+** Iterate through a range of entries in the FTS index, invoking the xVisit
+** callback for each of them.
+**
+** Parameter pToken points to an nToken buffer containing an FTS index term
+** (i.e. a document term with the preceding 1 byte index identifier -
+** FTS5_MAIN_PREFIX or similar). If bPrefix is true, then the call visits
+** all entries for terms that have pToken/nToken as a prefix. If bPrefix
+** is false, then only entries with pToken/nToken as the entire key are
+** visited.
+**
+** If the current table is a tokendata=1 table, then if bPrefix is true then
+** each index term is treated separately. However, if bPrefix is false, then
+** all index terms corresponding to pToken/nToken are collapsed into a single
+** term before the callback is invoked.
+**
+** The callback invoked for each entry visited is specified by paramter xVisit.
+** Each time it is invoked, it is passed a pointer to the Fts5Index object,
+** a copy of the 7th paramter to this function (pCtx) and a pointer to the
+** iterator that indicates the current entry. If the current entry is the
+** first with a new term (i.e. different from that of the previous entry,
+** including the very first term), then the final two parameters are passed
+** a pointer to the term and its size in bytes, respectively. If the current
+** entry is not the first associated with its term, these two parameters
+** are passed 0.
+**
+** If parameter pColset is not NULL, then it is used to filter entries before
+** the callback is invoked.
+*/
+static int fts5VisitEntries(
+  Fts5Index *p,                   /* Fts5 index object */
+  Fts5Colset *pColset,            /* Columns filter to apply, or NULL */
+  u8 *pToken,                     /* Buffer containing token */
+  int nToken,                     /* Size of buffer pToken in bytes */
+  int bPrefix,                    /* True for a prefix scan */
+  void (*xVisit)(Fts5Index*, void *pCtx, Fts5Iter *pIter, const u8*, int),
+  void *pCtx                      /* Passed as second argument to xVisit() */
+){
+  const int flags = (bPrefix ? FTS5INDEX_QUERY_SCAN : 0)
+                  | FTS5INDEX_QUERY_SKIPEMPTY
+                  | FTS5INDEX_QUERY_NOOUTPUT;
+  Fts5Iter *p1 = 0;     /* Iterator used to gather data from index */
+  int bNewTerm = 1;
+  Fts5Structure *pStruct = fts5StructureRead(p);
+
+  fts5MultiIterNew(p, pStruct, flags, pColset, pToken, nToken, -1, 0, &p1);
+  fts5IterSetOutputCb(&p->rc, p1);
+  for( /* no-op */ ;
+      fts5MultiIterEof(p, p1)==0;
+      fts5MultiIterNext2(p, p1, &bNewTerm)
+  ){
+    Fts5SegIter *pSeg = &p1->aSeg[ p1->aFirst[1].iFirst ];
+    int nNew = 0;
+    const u8 *pNew = 0;
+
+    p1->xSetOutputs(p1, pSeg);
+    if( p->rc ) break;
+
+    if( bNewTerm ){
+      nNew = pSeg->term.n;
+      pNew = pSeg->term.p;
+      if( nNew<nToken || memcmp(pToken, pNew, nToken) ) break;
+    }
+
+    xVisit(p, pCtx, p1, pNew, nNew);
+  }
+  fts5MultiIterFree(p1);
+
+  fts5StructureRelease(pStruct);
+  return p->rc;
+}
+
+
+/*
+** Usually, a tokendata=1 iterator (struct Fts5TokenDataIter) accumulates an
+** array of these for each row it visits (so all iRowid fields are the same).
+** Or, for an iterator used by an "ORDER BY rank" query, it accumulates an
+** array of these for the entire query (in which case iRowid fields may take
+** a variety of values).
+**
+** Each instance in the array indicates the iterator (and therefore term)
+** associated with position iPos of rowid iRowid. This is used by the
+** xInstToken() API.
+**
+** iRowid:
+**   Rowid for the current entry.
+**
+** iPos:
+**   Position of current entry within row. In the usual ((iCol<<32)+iOff)
+**   format (e.g. see macros FTS5_POS2COLUMN() and FTS5_POS2OFFSET()).
+**
+** iIter:
+**   If the Fts5TokenDataIter iterator that the entry is part of is
+**   actually an iterator (i.e. with nIter>0, not just a container for
+**   Fts5TokenDataMap structures), then this variable is an index into
+**   the apIter[] array. The corresponding term is that which the iterator
+**   at apIter[iIter] currently points to.
+**
+**   Or, if the Fts5TokenDataIter iterator is just a container object
+**   (nIter==0), then iIter is an index into the term.p[] buffer where
+**   the term is stored.
+**
+** nByte:
+**   In the case where iIter is an index into term.p[], this variable
+**   is the size of the term in bytes. If iIter is an index into apIter[],
+**   this variable is unused.
+*/
+struct Fts5TokenDataMap {
+  i64 iRowid;                     /* Row this token is located in */
+  i64 iPos;                       /* Position of token */
+  int iIter;                      /* Iterator token was read from */
+  int nByte;                      /* Length of token in bytes (or 0) */
+};
+
+/*
+** An object used to supplement Fts5Iter for tokendata=1 iterators.
+**
+** This object serves two purposes. The first is as a container for an array
+** of Fts5TokenDataMap structures, which are used to find the token required
+** when the xInstToken() API is used. This is done by the nMapAlloc, nMap and
+** aMap[] variables.
+*/
+struct Fts5TokenDataIter {
+  int nMapAlloc;                  /* Allocated size of aMap[] in entries */
+  int nMap;                       /* Number of valid entries in aMap[] */
+  Fts5TokenDataMap *aMap;         /* Array of (rowid+pos -> token) mappings */
+
+  /* The following are used for prefix-queries only. */
+  Fts5Buffer terms;
+
+  /* The following are used for other full-token tokendata queries only. */
+  int nIter;
+  int nIterAlloc;
+  Fts5PoslistReader *aPoslistReader;
+  int *aPoslistToIter;
+  Fts5Iter *apIter[1];
+};
+
+/*
+** The two input arrays - a1[] and a2[] - are in sorted order. This function
+** merges the two arrays together and writes the result to output array
+** aOut[]. aOut[] is guaranteed to be large enough to hold the result.
+**
+** Duplicate entries are copied into the output. So the size of the output
+** array is always (n1+n2) entries.
+*/
+static void fts5TokendataMerge(
+  Fts5TokenDataMap *a1, int n1,   /* Input array 1 */
+  Fts5TokenDataMap *a2, int n2,   /* Input array 2 */
+  Fts5TokenDataMap *aOut          /* Output array */
+){
+  int i1 = 0;
+  int i2 = 0;
+
+  assert( n1>=0 && n2>=0 );
+  while( i1<n1 || i2<n2 ){
+    Fts5TokenDataMap *pOut = &aOut[i1+i2];
+    if( i2>=n2 || (i1<n1 && (
+        a1[i1].iRowid<a2[i2].iRowid
+     || (a1[i1].iRowid==a2[i2].iRowid && a1[i1].iPos<=a2[i2].iPos)
+    ))){
+      memcpy(pOut, &a1[i1], sizeof(Fts5TokenDataMap));
+      i1++;
+    }else{
+      memcpy(pOut, &a2[i2], sizeof(Fts5TokenDataMap));
+      i2++;
+    }
+  }
+}
+
+
+/*
+** Append a mapping to the token-map belonging to object pT.
+*/
+static void fts5TokendataIterAppendMap(
+  Fts5Index *p,
+  Fts5TokenDataIter *pT,
+  int iIter,
+  int nByte,
+  i64 iRowid,
+  i64 iPos
+){
+  if( p->rc==SQLITE_OK ){
+    if( pT->nMap==pT->nMapAlloc ){
+      int nNew = pT->nMapAlloc ? pT->nMapAlloc*2 : 64;
+      int nAlloc = nNew * sizeof(Fts5TokenDataMap);
+      Fts5TokenDataMap *aNew;
+
+      aNew = (Fts5TokenDataMap*)sqlite3_realloc(pT->aMap, nAlloc);
+      if( aNew==0 ){
+        p->rc = SQLITE_NOMEM;
+        return;
+      }
+
+      pT->aMap = aNew;
+      pT->nMapAlloc = nNew;
+    }
+
+    pT->aMap[pT->nMap].iRowid = iRowid;
+    pT->aMap[pT->nMap].iPos = iPos;
+    pT->aMap[pT->nMap].iIter = iIter;
+    pT->aMap[pT->nMap].nByte = nByte;
+    pT->nMap++;
+  }
+}
+
+/*
+** Sort the contents of the pT->aMap[] array.
+**
+** The sorting algorithm requries a malloc(). If this fails, an error code
+** is left in Fts5Index.rc before returning.
+*/
+static void fts5TokendataIterSortMap(Fts5Index *p, Fts5TokenDataIter *pT){
+  Fts5TokenDataMap *aTmp = 0;
+  int nByte = pT->nMap * sizeof(Fts5TokenDataMap);
+
+  aTmp = (Fts5TokenDataMap*)sqlite3Fts5MallocZero(&p->rc, nByte);
+  if( aTmp ){
+    Fts5TokenDataMap *a1 = pT->aMap;
+    Fts5TokenDataMap *a2 = aTmp;
+    i64 nHalf;
+
+    for(nHalf=1; nHalf<pT->nMap; nHalf=nHalf*2){
+      int i1;
+      for(i1=0; i1<pT->nMap; i1+=(nHalf*2)){
+        int n1 = MIN(nHalf, pT->nMap-i1);
+        int n2 = MIN(nHalf, pT->nMap-i1-n1);
+        fts5TokendataMerge(&a1[i1], n1, &a1[i1+n1], n2, &a2[i1]);
+      }
+      SWAPVAL(Fts5TokenDataMap*, a1, a2);
+    }
+
+    if( a1!=pT->aMap ){
+      memcpy(pT->aMap, a1, pT->nMap*sizeof(Fts5TokenDataMap));
+    }
+    sqlite3_free(aTmp);
+
+#ifdef SQLITE_DEBUG
+    {
+      int ii;
+      for(ii=1; ii<pT->nMap; ii++){
+        Fts5TokenDataMap *p1 = &pT->aMap[ii-1];
+        Fts5TokenDataMap *p2 = &pT->aMap[ii];
+        assert( p1->iRowid<p2->iRowid
+             || (p1->iRowid==p2->iRowid && p1->iPos<=p2->iPos)
+        );
+      }
+    }
+#endif
+  }
+}
+
+/*
+** Delete an Fts5TokenDataIter structure and its contents.
+*/
+static void fts5TokendataIterDelete(Fts5TokenDataIter *pSet){
+  if( pSet ){
+    int ii;
+    for(ii=0; ii<pSet->nIter; ii++){
+      fts5MultiIterFree(pSet->apIter[ii]);
+    }
+    fts5BufferFree(&pSet->terms);
+    sqlite3_free(pSet->aPoslistReader);
+    sqlite3_free(pSet->aMap);
+    sqlite3_free(pSet);
+  }
+}
+
+
+/*
+** fts5VisitEntries() context object used by fts5SetupPrefixIterTokendata()
+** to pass data to prefixIterSetupTokendataCb().
+*/
+typedef struct TokendataSetupCtx TokendataSetupCtx;
+struct TokendataSetupCtx {
+  Fts5TokenDataIter *pT;          /* Object being populated with mappings */
+  int iTermOff;                   /* Offset of current term in terms.p[] */
+  int nTermByte;                  /* Size of current term in bytes */
+};
+
+/*
+** fts5VisitEntries() callback used by fts5SetupPrefixIterTokendata(). This
+** callback adds an entry to the Fts5TokenDataIter.aMap[] array for each
+** position in the current position-list. It doesn't matter that some of
+** these may be out of order - they will be sorted later.
+*/
+static void prefixIterSetupTokendataCb(
+  Fts5Index *p,
+  void *pCtx,
+  Fts5Iter *p1,
+  const u8 *pNew,
+  int nNew
+){
+  TokendataSetupCtx *pSetup = (TokendataSetupCtx*)pCtx;
+  int iPosOff = 0;
+  i64 iPos = 0;
+
+  if( pNew ){
+    pSetup->nTermByte = nNew-1;
+    pSetup->iTermOff = pSetup->pT->terms.n;
+    fts5BufferAppendBlob(&p->rc, &pSetup->pT->terms, nNew-1, pNew+1);
+  }
+
+  while( 0==sqlite3Fts5PoslistNext64(
+     p1->base.pData, p1->base.nData, &iPosOff, &iPos
+  ) ){
+    fts5TokendataIterAppendMap(p,
+        pSetup->pT, pSetup->iTermOff, pSetup->nTermByte, p1->base.iRowid, iPos
+    );
+  }
+}
+
+
+/*
+** Context object passed by fts5SetupPrefixIter() to fts5VisitEntries().
+*/
+typedef struct PrefixSetupCtx PrefixSetupCtx;
+struct PrefixSetupCtx {
+  void (*xMerge)(Fts5Index*, Fts5Buffer*, int, Fts5Buffer*);
+  void (*xAppend)(Fts5Index*, u64, Fts5Iter*, Fts5Buffer*);
+  i64 iLastRowid;
+  int nMerge;
+  Fts5Buffer *aBuf;
+  int nBuf;
+  Fts5Buffer doclist;
+  TokendataSetupCtx *pTokendata;
+};
+
+/*
+** fts5VisitEntries() callback used by fts5SetupPrefixIter()
+*/
+static void prefixIterSetupCb(
+  Fts5Index *p,
+  void *pCtx,
+  Fts5Iter *p1,
+  const u8 *pNew,
+  int nNew
+){
+  PrefixSetupCtx *pSetup = (PrefixSetupCtx*)pCtx;
+  const int nMerge = pSetup->nMerge;
+
+  if( p1->base.nData>0 ){
+    if( p1->base.iRowid<=pSetup->iLastRowid && pSetup->doclist.n>0 ){
+      int i;
+      for(i=0; p->rc==SQLITE_OK && pSetup->doclist.n; i++){
+        int i1 = i*nMerge;
+        int iStore;
+        assert( i1+nMerge<=pSetup->nBuf );
+        for(iStore=i1; iStore<i1+nMerge; iStore++){
+          if( pSetup->aBuf[iStore].n==0 ){
+            fts5BufferSwap(&pSetup->doclist, &pSetup->aBuf[iStore]);
+            fts5BufferZero(&pSetup->doclist);
+            break;
+          }
+        }
+        if( iStore==i1+nMerge ){
+          pSetup->xMerge(p, &pSetup->doclist, nMerge, &pSetup->aBuf[i1]);
+          for(iStore=i1; iStore<i1+nMerge; iStore++){
+            fts5BufferZero(&pSetup->aBuf[iStore]);
+          }
+        }
+      }
+      pSetup->iLastRowid = 0;
+    }
+
+    pSetup->xAppend(
+        p, (u64)p1->base.iRowid-(u64)pSetup->iLastRowid, p1, &pSetup->doclist
+    );
+    pSetup->iLastRowid = p1->base.iRowid;
+  }
+
+  if( pSetup->pTokendata ){
+    prefixIterSetupTokendataCb(p, (void*)pSetup->pTokendata, p1, pNew, nNew);
+  }
+}
+
+static void fts5SetupPrefixIter(
+  Fts5Index *p,                   /* Index to read from */
+  int bDesc,                      /* True for "ORDER BY rowid DESC" */
+  int iIdx,                       /* Index to scan for data */
+  u8 *pToken,                     /* Buffer containing prefix to match */
+  int nToken,                     /* Size of buffer pToken in bytes */
+  Fts5Colset *pColset,            /* Restrict matches to these columns */
+  Fts5Iter **ppIter               /* OUT: New iterator */
+){
+  Fts5Structure *pStruct;
+  PrefixSetupCtx s;
+  TokendataSetupCtx s2;
+
+  memset(&s, 0, sizeof(s));
+  memset(&s2, 0, sizeof(s2));
+
+  s.nMerge = 1;
+  s.iLastRowid = 0;
+  s.nBuf = 32;
+  if( iIdx==0
+   && p->pConfig->eDetail==FTS5_DETAIL_FULL
+   && p->pConfig->bPrefixInsttoken
+  ){
+    s.pTokendata = &s2;
+    s2.pT = (Fts5TokenDataIter*)fts5IdxMalloc(p, sizeof(*s2.pT));
+  }
+
+  if( p->pConfig->eDetail==FTS5_DETAIL_NONE ){
+    s.xMerge = fts5MergeRowidLists;
+    s.xAppend = fts5AppendRowid;
+  }else{
+    s.nMerge = FTS5_MERGE_NLIST-1;
+    s.nBuf = s.nMerge*8;   /* Sufficient to merge (16^8)==(2^32) lists */
+    s.xMerge = fts5MergePrefixLists;
+    s.xAppend = fts5AppendPoslist;
+  }
+
+  s.aBuf = (Fts5Buffer*)fts5IdxMalloc(p, sizeof(Fts5Buffer)*s.nBuf);
+  pStruct = fts5StructureRead(p);
+  assert( p->rc!=SQLITE_OK || (s.aBuf && pStruct) );
+
+  if( p->rc==SQLITE_OK ){
+    void *pCtx = (void*)&s;
+    int i;
+    Fts5Data *pData;
+
+    /* If iIdx is non-zero, then it is the number of a prefix-index for
+    ** prefixes 1 character longer than the prefix being queried for. That
+    ** index contains all the doclists required, except for the one
+    ** corresponding to the prefix itself. That one is extracted from the
+    ** main term index here.  */
+    if( iIdx!=0 ){
+      pToken[0] = FTS5_MAIN_PREFIX;
+      fts5VisitEntries(p, pColset, pToken, nToken, 0, prefixIterSetupCb, pCtx);
+    }
+
+    pToken[0] = FTS5_MAIN_PREFIX + iIdx;
+    fts5VisitEntries(p, pColset, pToken, nToken, 1, prefixIterSetupCb, pCtx);
+
+    assert( (s.nBuf%s.nMerge)==0 );
+    for(i=0; i<s.nBuf; i+=s.nMerge){
+      int iFree;
+      if( p->rc==SQLITE_OK ){
+        s.xMerge(p, &s.doclist, s.nMerge, &s.aBuf[i]);
+      }
+      for(iFree=i; iFree<i+s.nMerge; iFree++){
+        fts5BufferFree(&s.aBuf[iFree]);
+      }
+    }
+
+    pData = fts5IdxMalloc(p, sizeof(*pData)+s.doclist.n+FTS5_DATA_ZERO_PADDING);
+    assert( pData!=0 || p->rc!=SQLITE_OK );
+    if( pData ){
+      pData->p = (u8*)&pData[1];
+      pData->nn = pData->szLeaf = s.doclist.n;
+      if( s.doclist.n ) memcpy(pData->p, s.doclist.p, s.doclist.n);
+      fts5MultiIterNew2(p, pData, bDesc, ppIter);
+    }
+
+    assert( (*ppIter)!=0 || p->rc!=SQLITE_OK );
+    if( p->rc==SQLITE_OK && s.pTokendata ){
+      fts5TokendataIterSortMap(p, s2.pT);
+      (*ppIter)->pTokenDataIter = s2.pT;
+      s2.pT = 0;
+    }
+  }
+
+  fts5TokendataIterDelete(s2.pT);
+  fts5BufferFree(&s.doclist);
+  fts5StructureRelease(pStruct);
+  sqlite3_free(s.aBuf);
+}
+
+
+/*
+** Indicate that all subsequent calls to sqlite3Fts5IndexWrite() pertain
+** to the document with rowid iRowid.
+*/
+static int sqlite3Fts5IndexBeginWrite(Fts5Index *p, int bDelete, i64 iRowid){
+  assert( p->rc==SQLITE_OK );
+
+  /* Allocate the hash table if it has not already been allocated */
+  if( p->pHash==0 ){
+    p->rc = sqlite3Fts5HashNew(p->pConfig, &p->pHash, &p->nPendingData);
+  }
+
+  /* Flush the hash table to disk if required */
+  if( iRowid<p->iWriteRowid
+   || (iRowid==p->iWriteRowid && p->bDelete==0)
+   || (p->nPendingData > p->pConfig->nHashSize)
+  ){
+    fts5IndexFlush(p);
+  }
+
+  p->iWriteRowid = iRowid;
+  p->bDelete = bDelete;
+  if( bDelete==0 ){
+    p->nPendingRow++;
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** Commit data to disk.
+*/
+static int sqlite3Fts5IndexSync(Fts5Index *p){
+  assert( p->rc==SQLITE_OK );
+  fts5IndexFlush(p);
+  fts5IndexCloseReader(p);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Discard any data stored in the in-memory hash tables. Do not write it
+** to the database. Additionally, assume that the contents of the %_data
+** table may have changed on disk. So any in-memory caches of %_data
+** records must be invalidated.
+*/
+static int sqlite3Fts5IndexRollback(Fts5Index *p){
+  fts5IndexCloseReader(p);
+  fts5IndexDiscardData(p);
+  fts5StructureInvalidate(p);
+  return fts5IndexReturn(p);
+}
+
+/*
+** The %_data table is completely empty when this function is called. This
+** function populates it with the initial structure objects for each index,
+** and the initial version of the "averages" record (a zero-byte blob).
+*/
+static int sqlite3Fts5IndexReinit(Fts5Index *p){
+  Fts5Structure s;
+  fts5StructureInvalidate(p);
+  fts5IndexDiscardData(p);
+  memset(&s, 0, sizeof(Fts5Structure));
+  if( p->pConfig->bContentlessDelete ){
+    s.nOriginCntr = 1;
+  }
+  fts5DataWrite(p, FTS5_AVERAGES_ROWID, (const u8*)"", 0);
+  fts5StructureWrite(p, &s);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Open a new Fts5Index handle. If the bCreate argument is true, create
+** and initialize the underlying %_data table.
+**
+** If successful, set *pp to point to the new object and return SQLITE_OK.
+** Otherwise, set *pp to NULL and return an SQLite error code.
+*/
+static int sqlite3Fts5IndexOpen(
+  Fts5Config *pConfig,
+  int bCreate,
+  Fts5Index **pp,
+  char **pzErr
+){
+  int rc = SQLITE_OK;
+  Fts5Index *p;                   /* New object */
+
+  *pp = p = (Fts5Index*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Index));
+  if( rc==SQLITE_OK ){
+    p->pConfig = pConfig;
+    p->nWorkUnit = FTS5_WORK_UNIT;
+    p->zDataTbl = sqlite3Fts5Mprintf(&rc, "%s_data", pConfig->zName);
+    if( p->zDataTbl && bCreate ){
+      rc = sqlite3Fts5CreateTable(
+          pConfig, "data", "id INTEGER PRIMARY KEY, block BLOB", 0, pzErr
+      );
+      if( rc==SQLITE_OK ){
+        rc = sqlite3Fts5CreateTable(pConfig, "idx",
+            "segid, term, pgno, PRIMARY KEY(segid, term)",
+            1, pzErr
+        );
+      }
+      if( rc==SQLITE_OK ){
+        rc = sqlite3Fts5IndexReinit(p);
+      }
+    }
+  }
+
+  assert( rc!=SQLITE_OK || p->rc==SQLITE_OK );
+  if( rc ){
+    sqlite3Fts5IndexClose(p);
+    *pp = 0;
+  }
+  return rc;
+}
+
+/*
+** Close a handle opened by an earlier call to sqlite3Fts5IndexOpen().
+*/
+static int sqlite3Fts5IndexClose(Fts5Index *p){
+  int rc = SQLITE_OK;
+  if( p ){
+    assert( p->pReader==0 );
+    fts5StructureInvalidate(p);
+    sqlite3_finalize(p->pWriter);
+    sqlite3_finalize(p->pDeleter);
+    sqlite3_finalize(p->pIdxWriter);
+    sqlite3_finalize(p->pIdxDeleter);
+    sqlite3_finalize(p->pIdxSelect);
+    sqlite3_finalize(p->pIdxNextSelect);
+    sqlite3_finalize(p->pDataVersion);
+    sqlite3_finalize(p->pDeleteFromIdx);
+    sqlite3Fts5HashFree(p->pHash);
+    sqlite3_free(p->zDataTbl);
+    sqlite3_free(p);
+  }
+  return rc;
+}
+
+/*
+** Argument p points to a buffer containing utf-8 text that is n bytes in
+** size. Return the number of bytes in the nChar character prefix of the
+** buffer, or 0 if there are less than nChar characters in total.
+*/
+static int sqlite3Fts5IndexCharlenToBytelen(
+  const char *p,
+  int nByte,
+  int nChar
+){
+  int n = 0;
+  int i;
+  for(i=0; i<nChar; i++){
+    if( n>=nByte ) return 0;      /* Input contains fewer than nChar chars */
+    if( (unsigned char)p[n++]>=0xc0 ){
+      if( n>=nByte ) return 0;
+      while( (p[n] & 0xc0)==0x80 ){
+        n++;
+        if( n>=nByte ){
+          if( i+1==nChar ) break;
+          return 0;
+        }
+      }
+    }
+  }
+  return n;
+}
+
+/*
+** pIn is a UTF-8 encoded string, nIn bytes in size. Return the number of
+** unicode characters in the string.
+*/
+static int fts5IndexCharlen(const char *pIn, int nIn){
+  int nChar = 0;
+  int i = 0;
+  while( i<nIn ){
+    if( (unsigned char)pIn[i++]>=0xc0 ){
+      while( i<nIn && (pIn[i] & 0xc0)==0x80 ) i++;
+    }
+    nChar++;
+  }
+  return nChar;
+}
+
+/*
+** Insert or remove data to or from the index. Each time a document is
+** added to or removed from the index, this function is called one or more
+** times.
+**
+** For an insert, it must be called once for each token in the new document.
+** If the operation is a delete, it must be called (at least) once for each
+** unique token in the document with an iCol value less than zero. The iPos
+** argument is ignored for a delete.
+*/
+static int sqlite3Fts5IndexWrite(
+  Fts5Index *p,                   /* Index to write to */
+  int iCol,                       /* Column token appears in (-ve -> delete) */
+  int iPos,                       /* Position of token within column */
+  const char *pToken, int nToken  /* Token to add or remove to or from index */
+){
+  int i;                          /* Used to iterate through indexes */
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5Config *pConfig = p->pConfig;
+
+  assert( p->rc==SQLITE_OK );
+  assert( (iCol<0)==p->bDelete );
+
+  /* Add the entry to the main terms index. */
+  rc = sqlite3Fts5HashWrite(
+      p->pHash, p->iWriteRowid, iCol, iPos, FTS5_MAIN_PREFIX, pToken, nToken
+  );
+
+  for(i=0; i<pConfig->nPrefix && rc==SQLITE_OK; i++){
+    const int nChar = pConfig->aPrefix[i];
+    int nByte = sqlite3Fts5IndexCharlenToBytelen(pToken, nToken, nChar);
+    if( nByte ){
+      rc = sqlite3Fts5HashWrite(p->pHash,
+          p->iWriteRowid, iCol, iPos, (char)(FTS5_MAIN_PREFIX+i+1), pToken,
+          nByte
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** pToken points to a buffer of size nToken bytes containing a search
+** term, including the index number at the start, used on a tokendata=1
+** table. This function returns true if the term in buffer pBuf matches
+** token pToken/nToken.
+*/
+static int fts5IsTokendataPrefix(
+  Fts5Buffer *pBuf,
+  const u8 *pToken,
+  int nToken
+){
+  return (
+      pBuf->n>=nToken
+   && 0==memcmp(pBuf->p, pToken, nToken)
+   && (pBuf->n==nToken || pBuf->p[nToken]==0x00)
+  );
+}
+
+/*
+** Ensure the segment-iterator passed as the only argument points to EOF.
+*/
+static void fts5SegIterSetEOF(Fts5SegIter *pSeg){
+  fts5DataRelease(pSeg->pLeaf);
+  pSeg->pLeaf = 0;
+}
+
+static void fts5IterClose(Fts5IndexIter *pIndexIter){
+  if( pIndexIter ){
+    Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+    Fts5Index *pIndex = pIter->pIndex;
+    fts5TokendataIterDelete(pIter->pTokenDataIter);
+    fts5MultiIterFree(pIter);
+    fts5IndexCloseReader(pIndex);
+  }
+}
+
+/*
+** This function appends iterator pAppend to Fts5TokenDataIter pIn and
+** returns the result.
+*/
+static Fts5TokenDataIter *fts5AppendTokendataIter(
+  Fts5Index *p,                   /* Index object (for error code) */
+  Fts5TokenDataIter *pIn,         /* Current Fts5TokenDataIter struct */
+  Fts5Iter *pAppend               /* Append this iterator */
+){
+  Fts5TokenDataIter *pRet = pIn;
+
+  if( p->rc==SQLITE_OK ){
+    if( pIn==0 || pIn->nIter==pIn->nIterAlloc ){
+      int nAlloc = pIn ? pIn->nIterAlloc*2 : 16;
+      int nByte = nAlloc * sizeof(Fts5Iter*) + sizeof(Fts5TokenDataIter);
+      Fts5TokenDataIter *pNew = (Fts5TokenDataIter*)sqlite3_realloc(pIn, nByte);
+
+      if( pNew==0 ){
+        p->rc = SQLITE_NOMEM;
+      }else{
+        if( pIn==0 ) memset(pNew, 0, nByte);
+        pRet = pNew;
+        pNew->nIterAlloc = nAlloc;
+      }
+    }
+  }
+  if( p->rc ){
+    fts5IterClose((Fts5IndexIter*)pAppend);
+  }else{
+    pRet->apIter[pRet->nIter++] = pAppend;
+  }
+  assert( pRet==0 || pRet->nIter<=pRet->nIterAlloc );
+
+  return pRet;
+}
+
+/*
+** The iterator passed as the only argument must be a tokendata=1 iterator
+** (pIter->pTokenDataIter!=0). This function sets the iterator output
+** variables (pIter->base.*) according to the contents of the current
+** row.
+*/
+static void fts5IterSetOutputsTokendata(Fts5Iter *pIter){
+  int ii;
+  int nHit = 0;
+  i64 iRowid = SMALLEST_INT64;
+  int iMin = 0;
+
+  Fts5TokenDataIter *pT = pIter->pTokenDataIter;
+
+  pIter->base.nData = 0;
+  pIter->base.pData = 0;
+
+  for(ii=0; ii<pT->nIter; ii++){
+    Fts5Iter *p = pT->apIter[ii];
+    if( p->base.bEof==0 ){
+      if( nHit==0 || p->base.iRowid<iRowid ){
+        iRowid = p->base.iRowid;
+        nHit = 1;
+        pIter->base.pData = p->base.pData;
+        pIter->base.nData = p->base.nData;
+        iMin = ii;
+      }else if( p->base.iRowid==iRowid ){
+        nHit++;
+      }
+    }
+  }
+
+  if( nHit==0 ){
+    pIter->base.bEof = 1;
+  }else{
+    int eDetail = pIter->pIndex->pConfig->eDetail;
+    pIter->base.bEof = 0;
+    pIter->base.iRowid = iRowid;
+
+    if( nHit==1 && eDetail==FTS5_DETAIL_FULL ){
+      fts5TokendataIterAppendMap(pIter->pIndex, pT, iMin, 0, iRowid, -1);
+    }else
+    if( nHit>1 && eDetail!=FTS5_DETAIL_NONE ){
+      int nReader = 0;
+      int nByte = 0;
+      i64 iPrev = 0;
+
+      /* Allocate array of iterators if they are not already allocated. */
+      if( pT->aPoslistReader==0 ){
+        pT->aPoslistReader = (Fts5PoslistReader*)sqlite3Fts5MallocZero(
+            &pIter->pIndex->rc,
+            pT->nIter * (sizeof(Fts5PoslistReader) + sizeof(int))
+        );
+        if( pT->aPoslistReader==0 ) return;
+        pT->aPoslistToIter = (int*)&pT->aPoslistReader[pT->nIter];
+      }
+
+      /* Populate an iterator for each poslist that will be merged */
+      for(ii=0; ii<pT->nIter; ii++){
+        Fts5Iter *p = pT->apIter[ii];
+        if( iRowid==p->base.iRowid ){
+          pT->aPoslistToIter[nReader] = ii;
+          sqlite3Fts5PoslistReaderInit(
+              p->base.pData, p->base.nData, &pT->aPoslistReader[nReader++]
+          );
+          nByte += p->base.nData;
+        }
+      }
+
+      /* Ensure the output buffer is large enough */
+      if( fts5BufferGrow(&pIter->pIndex->rc, &pIter->poslist, nByte+nHit*10) ){
+        return;
+      }
+
+      /* Ensure the token-mapping is large enough */
+      if( eDetail==FTS5_DETAIL_FULL && pT->nMapAlloc<(pT->nMap + nByte) ){
+        int nNew = (pT->nMapAlloc + nByte) * 2;
+        Fts5TokenDataMap *aNew = (Fts5TokenDataMap*)sqlite3_realloc(
+            pT->aMap, nNew*sizeof(Fts5TokenDataMap)
+        );
+        if( aNew==0 ){
+          pIter->pIndex->rc = SQLITE_NOMEM;
+          return;
+        }
+        pT->aMap = aNew;
+        pT->nMapAlloc = nNew;
+      }
+
+      pIter->poslist.n = 0;
+
+      while( 1 ){
+        i64 iMinPos = LARGEST_INT64;
+
+        /* Find smallest position */
+        iMin = 0;
+        for(ii=0; ii<nReader; ii++){
+          Fts5PoslistReader *pReader = &pT->aPoslistReader[ii];
+          if( pReader->bEof==0 ){
+            if( pReader->iPos<iMinPos ){
+              iMinPos = pReader->iPos;
+              iMin = ii;
+            }
+          }
+        }
+
+        /* If all readers were at EOF, break out of the loop. */
+        if( iMinPos==LARGEST_INT64 ) break;
+
+        sqlite3Fts5PoslistSafeAppend(&pIter->poslist, &iPrev, iMinPos);
+        sqlite3Fts5PoslistReaderNext(&pT->aPoslistReader[iMin]);
+
+        if( eDetail==FTS5_DETAIL_FULL ){
+          pT->aMap[pT->nMap].iPos = iMinPos;
+          pT->aMap[pT->nMap].iIter = pT->aPoslistToIter[iMin];
+          pT->aMap[pT->nMap].iRowid = iRowid;
+          pT->nMap++;
+        }
+      }
+
+      pIter->base.pData = pIter->poslist.p;
+      pIter->base.nData = pIter->poslist.n;
+    }
+  }
+}
+
+/*
+** The iterator passed as the only argument must be a tokendata=1 iterator
+** (pIter->pTokenDataIter!=0). This function advances the iterator. If
+** argument bFrom is false, then the iterator is advanced to the next
+** entry. Or, if bFrom is true, it is advanced to the first entry with
+** a rowid of iFrom or greater.
+*/
+static void fts5TokendataIterNext(Fts5Iter *pIter, int bFrom, i64 iFrom){
+  int ii;
+  Fts5TokenDataIter *pT = pIter->pTokenDataIter;
+  Fts5Index *pIndex = pIter->pIndex;
+
+  for(ii=0; ii<pT->nIter; ii++){
+    Fts5Iter *p = pT->apIter[ii];
+    if( p->base.bEof==0
+     && (p->base.iRowid==pIter->base.iRowid || (bFrom && p->base.iRowid<iFrom))
+    ){
+      fts5MultiIterNext(pIndex, p, bFrom, iFrom);
+      while( bFrom && p->base.bEof==0
+          && p->base.iRowid<iFrom
+          && pIndex->rc==SQLITE_OK
+      ){
+        fts5MultiIterNext(pIndex, p, 0, 0);
+      }
+    }
+  }
+
+  if( pIndex->rc==SQLITE_OK ){
+    fts5IterSetOutputsTokendata(pIter);
+  }
+}
+
+/*
+** If the segment-iterator passed as the first argument is at EOF, then
+** set pIter->term to a copy of buffer pTerm.
+*/
+static void fts5TokendataSetTermIfEof(Fts5Iter *pIter, Fts5Buffer *pTerm){
+  if( pIter && pIter->aSeg[0].pLeaf==0 ){
+    fts5BufferSet(&pIter->pIndex->rc, &pIter->aSeg[0].term, pTerm->n, pTerm->p);
+  }
+}
+
+/*
+** This function sets up an iterator to use for a non-prefix query on a
+** tokendata=1 table.
+*/
+static Fts5Iter *fts5SetupTokendataIter(
+  Fts5Index *p,                   /* FTS index to query */
+  const u8 *pToken,               /* Buffer containing query term */
+  int nToken,                     /* Size of buffer pToken in bytes */
+  Fts5Colset *pColset             /* Colset to filter on */
+){
+  Fts5Iter *pRet = 0;
+  Fts5TokenDataIter *pSet = 0;
+  Fts5Structure *pStruct = 0;
+  const int flags = FTS5INDEX_QUERY_SCANONETERM | FTS5INDEX_QUERY_SCAN;
+
+  Fts5Buffer bSeek = {0, 0, 0};
+  Fts5Buffer *pSmall = 0;
+
+  fts5IndexFlush(p);
+  pStruct = fts5StructureRead(p);
+
+  while( p->rc==SQLITE_OK ){
+    Fts5Iter *pPrev = pSet ? pSet->apIter[pSet->nIter-1] : 0;
+    Fts5Iter *pNew = 0;
+    Fts5SegIter *pNewIter = 0;
+    Fts5SegIter *pPrevIter = 0;
+
+    int iLvl, iSeg, ii;
+
+    pNew = fts5MultiIterAlloc(p, pStruct->nSegment);
+    if( pSmall ){
+      fts5BufferSet(&p->rc, &bSeek, pSmall->n, pSmall->p);
+      fts5BufferAppendBlob(&p->rc, &bSeek, 1, (const u8*)"\0");
+    }else{
+      fts5BufferSet(&p->rc, &bSeek, nToken, pToken);
+    }
+    if( p->rc ){
+      fts5IterClose((Fts5IndexIter*)pNew);
+      break;
+    }
+
+    pNewIter = &pNew->aSeg[0];
+    pPrevIter = (pPrev ? &pPrev->aSeg[0] : 0);
+    for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+      for(iSeg=pStruct->aLevel[iLvl].nSeg-1; iSeg>=0; iSeg--){
+        Fts5StructureSegment *pSeg = &pStruct->aLevel[iLvl].aSeg[iSeg];
+        int bDone = 0;
+
+        if( pPrevIter ){
+          if( fts5BufferCompare(pSmall, &pPrevIter->term) ){
+            memcpy(pNewIter, pPrevIter, sizeof(Fts5SegIter));
+            memset(pPrevIter, 0, sizeof(Fts5SegIter));
+            bDone = 1;
+          }else if( pPrevIter->iEndofDoclist>pPrevIter->pLeaf->szLeaf ){
+            fts5SegIterNextInit(p,(const char*)bSeek.p,bSeek.n-1,pSeg,pNewIter);
+            bDone = 1;
+          }
+        }
+
+        if( bDone==0 ){
+          fts5SegIterSeekInit(p, bSeek.p, bSeek.n, flags, pSeg, pNewIter);
+        }
+
+        if( pPrevIter ){
+          if( pPrevIter->pTombArray ){
+            pNewIter->pTombArray = pPrevIter->pTombArray;
+            pNewIter->pTombArray->nRef++;
+          }
+        }else{
+          fts5SegIterAllocTombstone(p, pNewIter);
+        }
+
+        pNewIter++;
+        if( pPrevIter ) pPrevIter++;
+        if( p->rc ) break;
+      }
+    }
+    fts5TokendataSetTermIfEof(pPrev, pSmall);
+
+    pNew->bSkipEmpty = 1;
+    pNew->pColset = pColset;
+    fts5IterSetOutputCb(&p->rc, pNew);
+
+    /* Loop through all segments in the new iterator. Find the smallest
+    ** term that any segment-iterator points to. Iterator pNew will be
+    ** used for this term. Also, set any iterator that points to a term that
+    ** does not match pToken/nToken to point to EOF */
+    pSmall = 0;
+    for(ii=0; ii<pNew->nSeg; ii++){
+      Fts5SegIter *pII = &pNew->aSeg[ii];
+      if( 0==fts5IsTokendataPrefix(&pII->term, pToken, nToken) ){
+        fts5SegIterSetEOF(pII);
+      }
+      if( pII->pLeaf && (!pSmall || fts5BufferCompare(pSmall, &pII->term)>0) ){
+        pSmall = &pII->term;
+      }
+    }
+
+    /* If pSmall is still NULL at this point, then the new iterator does
+    ** not point to any terms that match the query. So delete it and break
+    ** out of the loop - all required iterators have been collected.  */
+    if( pSmall==0 ){
+      fts5IterClose((Fts5IndexIter*)pNew);
+      break;
+    }
+
+    /* Append this iterator to the set and continue. */
+    pSet = fts5AppendTokendataIter(p, pSet, pNew);
+  }
+
+  if( p->rc==SQLITE_OK && pSet ){
+    int ii;
+    for(ii=0; ii<pSet->nIter; ii++){
+      Fts5Iter *pIter = pSet->apIter[ii];
+      int iSeg;
+      for(iSeg=0; iSeg<pIter->nSeg; iSeg++){
+        pIter->aSeg[iSeg].flags |= FTS5_SEGITER_ONETERM;
+      }
+      fts5MultiIterFinishSetup(p, pIter);
+    }
+  }
+
+  if( p->rc==SQLITE_OK ){
+    pRet = fts5MultiIterAlloc(p, 0);
+  }
+  if( pRet ){
+    pRet->nSeg = 0;
+    pRet->pTokenDataIter = pSet;
+    if( pSet ){
+      fts5IterSetOutputsTokendata(pRet);
+    }else{
+      pRet->base.bEof = 1;
+    }
+  }else{
+    fts5TokendataIterDelete(pSet);
+  }
+
+  fts5StructureRelease(pStruct);
+  fts5BufferFree(&bSeek);
+  return pRet;
+}
+
+/*
+** Open a new iterator to iterate though all rowid that match the
+** specified token or token prefix.
+*/
+static int sqlite3Fts5IndexQuery(
+  Fts5Index *p,                   /* FTS index to query */
+  const char *pToken, int nToken, /* Token (or prefix) to query for */
+  int flags,                      /* Mask of FTS5INDEX_QUERY_X flags */
+  Fts5Colset *pColset,            /* Match these columns only */
+  Fts5IndexIter **ppIter          /* OUT: New iterator object */
+){
+  Fts5Config *pConfig = p->pConfig;
+  Fts5Iter *pRet = 0;
+  Fts5Buffer buf = {0, 0, 0};
+
+  /* If the QUERY_SCAN flag is set, all other flags must be clear. */
+  assert( (flags & FTS5INDEX_QUERY_SCAN)==0 || flags==FTS5INDEX_QUERY_SCAN );
+
+  if( sqlite3Fts5BufferSize(&p->rc, &buf, nToken+1)==0 ){
+    int iIdx = 0;                 /* Index to search */
+    int iPrefixIdx = 0;           /* +1 prefix index */
+    int bTokendata = pConfig->bTokendata;
+    assert( buf.p!=0 );
+    if( nToken>0 ) memcpy(&buf.p[1], pToken, nToken);
+
+    /* The NOTOKENDATA flag is set when each token in a tokendata=1 table
+    ** should be treated individually, instead of merging all those with
+    ** a common prefix into a single entry. This is used, for example, by
+    ** queries performed as part of an integrity-check, or by the fts5vocab
+    ** module.  */
+    if( flags & (FTS5INDEX_QUERY_NOTOKENDATA|FTS5INDEX_QUERY_SCAN) ){
+      bTokendata = 0;
+    }
+
+    /* Figure out which index to search and set iIdx accordingly. If this
+    ** is a prefix query for which there is no prefix index, set iIdx to
+    ** greater than pConfig->nPrefix to indicate that the query will be
+    ** satisfied by scanning multiple terms in the main index.
+    **
+    ** If the QUERY_TEST_NOIDX flag was specified, then this must be a
+    ** prefix-query. Instead of using a prefix-index (if one exists),
+    ** evaluate the prefix query using the main FTS index. This is used
+    ** for internal sanity checking by the integrity-check in debug
+    ** mode only.  */
+#ifdef SQLITE_DEBUG
+    if( pConfig->bPrefixIndex==0 || (flags & FTS5INDEX_QUERY_TEST_NOIDX) ){
+      assert( flags & FTS5INDEX_QUERY_PREFIX );
+      iIdx = 1+pConfig->nPrefix;
+    }else
+#endif
+    if( flags & FTS5INDEX_QUERY_PREFIX ){
+      int nChar = fts5IndexCharlen(pToken, nToken);
+      for(iIdx=1; iIdx<=pConfig->nPrefix; iIdx++){
+        int nIdxChar = pConfig->aPrefix[iIdx-1];
+        if( nIdxChar==nChar ) break;
+        if( nIdxChar==nChar+1 ) iPrefixIdx = iIdx;
+      }
+    }
+
+    if( bTokendata && iIdx==0 ){
+      buf.p[0] = FTS5_MAIN_PREFIX;
+      pRet = fts5SetupTokendataIter(p, buf.p, nToken+1, pColset);
+    }else if( iIdx<=pConfig->nPrefix ){
+      /* Straight index lookup */
+      Fts5Structure *pStruct = fts5StructureRead(p);
+      buf.p[0] = (u8)(FTS5_MAIN_PREFIX + iIdx);
+      if( pStruct ){
+        fts5MultiIterNew(p, pStruct, flags | FTS5INDEX_QUERY_SKIPEMPTY,
+            pColset, buf.p, nToken+1, -1, 0, &pRet
+        );
+        fts5StructureRelease(pStruct);
+      }
+    }else{
+      /* Scan multiple terms in the main index for a prefix query. */
+      int bDesc = (flags & FTS5INDEX_QUERY_DESC)!=0;
+      fts5SetupPrefixIter(p, bDesc, iPrefixIdx, buf.p, nToken+1, pColset,&pRet);
+      if( pRet==0 ){
+        assert( p->rc!=SQLITE_OK );
+      }else{
+        assert( pRet->pColset==0 );
+        fts5IterSetOutputCb(&p->rc, pRet);
+        if( p->rc==SQLITE_OK ){
+          Fts5SegIter *pSeg = &pRet->aSeg[pRet->aFirst[1].iFirst];
+          if( pSeg->pLeaf ) pRet->xSetOutputs(pRet, pSeg);
+        }
+      }
+    }
+
+    if( p->rc ){
+      fts5IterClose((Fts5IndexIter*)pRet);
+      pRet = 0;
+      fts5IndexCloseReader(p);
+    }
+
+    *ppIter = (Fts5IndexIter*)pRet;
+    sqlite3Fts5BufferFree(&buf);
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** Return true if the iterator passed as the only argument is at EOF.
+*/
+/*
+** Move to the next matching rowid.
+*/
+static int sqlite3Fts5IterNext(Fts5IndexIter *pIndexIter){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  assert( pIter->pIndex->rc==SQLITE_OK );
+  if( pIter->nSeg==0 ){
+    assert( pIter->pTokenDataIter );
+    fts5TokendataIterNext(pIter, 0, 0);
+  }else{
+    fts5MultiIterNext(pIter->pIndex, pIter, 0, 0);
+  }
+  return fts5IndexReturn(pIter->pIndex);
+}
+
+/*
+** Move to the next matching term/rowid. Used by the fts5vocab module.
+*/
+static int sqlite3Fts5IterNextScan(Fts5IndexIter *pIndexIter){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  Fts5Index *p = pIter->pIndex;
+
+  assert( pIter->pIndex->rc==SQLITE_OK );
+
+  fts5MultiIterNext(p, pIter, 0, 0);
+  if( p->rc==SQLITE_OK ){
+    Fts5SegIter *pSeg = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
+    if( pSeg->pLeaf && pSeg->term.p[0]!=FTS5_MAIN_PREFIX ){
+      fts5DataRelease(pSeg->pLeaf);
+      pSeg->pLeaf = 0;
+      pIter->base.bEof = 1;
+    }
+  }
+
+  return fts5IndexReturn(pIter->pIndex);
+}
+
+/*
+** Move to the next matching rowid that occurs at or after iMatch. The
+** definition of "at or after" depends on whether this iterator iterates
+** in ascending or descending rowid order.
+*/
+static int sqlite3Fts5IterNextFrom(Fts5IndexIter *pIndexIter, i64 iMatch){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  if( pIter->nSeg==0 ){
+    assert( pIter->pTokenDataIter );
+    fts5TokendataIterNext(pIter, 1, iMatch);
+  }else{
+    fts5MultiIterNextFrom(pIter->pIndex, pIter, iMatch);
+  }
+  return fts5IndexReturn(pIter->pIndex);
+}
+
+/*
+** Return the current term.
+*/
+static const char *sqlite3Fts5IterTerm(Fts5IndexIter *pIndexIter, int *pn){
+  int n;
+  const char *z = (const char*)fts5MultiIterTerm((Fts5Iter*)pIndexIter, &n);
+  assert_nc( z || n<=1 );
+  *pn = n-1;
+  return (z ? &z[1] : 0);
+}
+
+/*
+** pIter is a prefix query. This function populates pIter->pTokenDataIter
+** with an Fts5TokenDataIter object containing mappings for all rows
+** matched by the query.
+*/
+static int fts5SetupPrefixIterTokendata(
+  Fts5Iter *pIter,
+  const char *pToken,             /* Token prefix to search for */
+  int nToken                      /* Size of pToken in bytes */
+){
+  Fts5Index *p = pIter->pIndex;
+  Fts5Buffer token = {0, 0, 0};
+  TokendataSetupCtx ctx;
+
+  memset(&ctx, 0, sizeof(ctx));
+
+  fts5BufferGrow(&p->rc, &token, nToken+1);
+  assert( token.p!=0 || p->rc!=SQLITE_OK );
+  ctx.pT = (Fts5TokenDataIter*)sqlite3Fts5MallocZero(&p->rc, sizeof(*ctx.pT));
+
+  if( p->rc==SQLITE_OK ){
+
+    /* Fill in the token prefix to search for */
+    token.p[0] = FTS5_MAIN_PREFIX;
+    memcpy(&token.p[1], pToken, nToken);
+    token.n = nToken+1;
+
+    fts5VisitEntries(
+        p, 0, token.p, token.n, 1, prefixIterSetupTokendataCb, (void*)&ctx
+    );
+
+    fts5TokendataIterSortMap(p, ctx.pT);
+  }
+
+  if( p->rc==SQLITE_OK ){
+    pIter->pTokenDataIter = ctx.pT;
+  }else{
+    fts5TokendataIterDelete(ctx.pT);
+  }
+  fts5BufferFree(&token);
+
+  return fts5IndexReturn(p);
+}
+
+/*
+** This is used by xInstToken() to access the token at offset iOff, column
+** iCol of row iRowid. The token is returned via output variables *ppOut
+** and *pnOut. The iterator passed as the first argument must be a tokendata=1
+** iterator (pIter->pTokenDataIter!=0).
+**
+** pToken/nToken:
+*/
+static int sqlite3Fts5IterToken(
+  Fts5IndexIter *pIndexIter,
+  const char *pToken, int nToken,
+  i64 iRowid,
+  int iCol,
+  int iOff,
+  const char **ppOut, int *pnOut
+){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  Fts5TokenDataIter *pT = pIter->pTokenDataIter;
+  i64 iPos = (((i64)iCol)<<32) + iOff;
+  Fts5TokenDataMap *aMap = 0;
+  int i1 = 0;
+  int i2 = 0;
+  int iTest = 0;
+
+  assert( pT || (pToken && pIter->nSeg>0) );
+  if( pT==0 ){
+    int rc = fts5SetupPrefixIterTokendata(pIter, pToken, nToken);
+    if( rc!=SQLITE_OK ) return rc;
+    pT = pIter->pTokenDataIter;
+  }
+
+  i2 = pT->nMap;
+  aMap = pT->aMap;
+
+  while( i2>i1 ){
+    iTest = (i1 + i2) / 2;
+
+    if( aMap[iTest].iRowid<iRowid ){
+      i1 = iTest+1;
+    }else if( aMap[iTest].iRowid>iRowid ){
+      i2 = iTest;
+    }else{
+      if( aMap[iTest].iPos<iPos ){
+        if( aMap[iTest].iPos<0 ){
+          break;
+        }
+        i1 = iTest+1;
+      }else if( aMap[iTest].iPos>iPos ){
+        i2 = iTest;
+      }else{
+        break;
+      }
+    }
+  }
+
+  if( i2>i1 ){
+    if( pIter->nSeg==0 ){
+      Fts5Iter *pMap = pT->apIter[aMap[iTest].iIter];
+      *ppOut = (const char*)pMap->aSeg[0].term.p+1;
+      *pnOut = pMap->aSeg[0].term.n-1;
+    }else{
+      Fts5TokenDataMap *p = &aMap[iTest];
+      *ppOut = (const char*)&pT->terms.p[p->iIter];
+      *pnOut = aMap[iTest].nByte;
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** Clear any existing entries from the token-map associated with the
+** iterator passed as the only argument.
+*/
+static void sqlite3Fts5IndexIterClearTokendata(Fts5IndexIter *pIndexIter){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  if( pIter && pIter->pTokenDataIter
+   && (pIter->nSeg==0 || pIter->pIndex->pConfig->eDetail!=FTS5_DETAIL_FULL)
+  ){
+    pIter->pTokenDataIter->nMap = 0;
+  }
+}
+
+/*
+** Set a token-mapping for the iterator passed as the first argument. This
+** is used in detail=column or detail=none mode when a token is requested
+** using the xInstToken() API. In this case the caller tokenizers the
+** current row and configures the token-mapping via multiple calls to this
+** function.
+*/
+static int sqlite3Fts5IndexIterWriteTokendata(
+  Fts5IndexIter *pIndexIter,
+  const char *pToken, int nToken,
+  i64 iRowid, int iCol, int iOff
+){
+  Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
+  Fts5TokenDataIter *pT = pIter->pTokenDataIter;
+  Fts5Index *p = pIter->pIndex;
+  i64 iPos = (((i64)iCol)<<32) + iOff;
+
+  assert( p->pConfig->eDetail!=FTS5_DETAIL_FULL );
+  assert( pIter->pTokenDataIter || pIter->nSeg>0 );
+  if( pIter->nSeg>0 ){
+    /* This is a prefix term iterator. */
+    if( pT==0 ){
+      pT = (Fts5TokenDataIter*)sqlite3Fts5MallocZero(&p->rc, sizeof(*pT));
+      pIter->pTokenDataIter = pT;
+    }
+    if( pT ){
+      fts5TokendataIterAppendMap(p, pT, pT->terms.n, nToken, iRowid, iPos);
+      fts5BufferAppendBlob(&p->rc, &pT->terms, nToken, (const u8*)pToken);
+    }
+  }else{
+    int ii;
+    for(ii=0; ii<pT->nIter; ii++){
+      Fts5Buffer *pTerm = &pT->apIter[ii]->aSeg[0].term;
+      if( nToken==pTerm->n-1 && memcmp(pToken, pTerm->p+1, nToken)==0 ) break;
+    }
+    if( ii<pT->nIter ){
+      fts5TokendataIterAppendMap(p, pT, ii, 0, iRowid, iPos);
+    }
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** Close an iterator opened by an earlier call to sqlite3Fts5IndexQuery().
+*/
+static void sqlite3Fts5IterClose(Fts5IndexIter *pIndexIter){
+  if( pIndexIter ){
+    Fts5Index *pIndex = ((Fts5Iter*)pIndexIter)->pIndex;
+    fts5IterClose(pIndexIter);
+    fts5IndexReturn(pIndex);
+  }
+}
+
+/*
+** Read and decode the "averages" record from the database.
+**
+** Parameter anSize must point to an array of size nCol, where nCol is
+** the number of user defined columns in the FTS table.
+*/
+static int sqlite3Fts5IndexGetAverages(Fts5Index *p, i64 *pnRow, i64 *anSize){
+  int nCol = p->pConfig->nCol;
+  Fts5Data *pData;
+
+  *pnRow = 0;
+  memset(anSize, 0, sizeof(i64) * nCol);
+  pData = fts5DataRead(p, FTS5_AVERAGES_ROWID);
+  if( p->rc==SQLITE_OK && pData->nn ){
+    int i = 0;
+    int iCol;
+    i += fts5GetVarint(&pData->p[i], (u64*)pnRow);
+    for(iCol=0; i<pData->nn && iCol<nCol; iCol++){
+      i += fts5GetVarint(&pData->p[i], (u64*)&anSize[iCol]);
+    }
+  }
+
+  fts5DataRelease(pData);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Replace the current "averages" record with the contents of the buffer
+** supplied as the second argument.
+*/
+static int sqlite3Fts5IndexSetAverages(Fts5Index *p, const u8 *pData, int nData){
+  assert( p->rc==SQLITE_OK );
+  fts5DataWrite(p, FTS5_AVERAGES_ROWID, pData, nData);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Return the total number of blocks this module has read from the %_data
+** table since it was created.
+*/
+static int sqlite3Fts5IndexReads(Fts5Index *p){
+  return p->nRead;
+}
+
+/*
+** Set the 32-bit cookie value stored at the start of all structure
+** records to the value passed as the second argument.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int sqlite3Fts5IndexSetCookie(Fts5Index *p, int iNew){
+  int rc;                              /* Return code */
+  Fts5Config *pConfig = p->pConfig;    /* Configuration object */
+  u8 aCookie[4];                       /* Binary representation of iNew */
+  sqlite3_blob *pBlob = 0;
+
+  assert( p->rc==SQLITE_OK );
+  sqlite3Fts5Put32(aCookie, iNew);
+
+  rc = sqlite3_blob_open(pConfig->db, pConfig->zDb, p->zDataTbl,
+      "block", FTS5_STRUCTURE_ROWID, 1, &pBlob
+  );
+  if( rc==SQLITE_OK ){
+    sqlite3_blob_write(pBlob, aCookie, 4, 0);
+    rc = sqlite3_blob_close(pBlob);
+  }
+
+  return rc;
+}
+
+static int sqlite3Fts5IndexLoadConfig(Fts5Index *p){
+  Fts5Structure *pStruct;
+  pStruct = fts5StructureRead(p);
+  fts5StructureRelease(pStruct);
+  return fts5IndexReturn(p);
+}
+
+/*
+** Retrieve the origin value that will be used for the segment currently
+** being accumulated in the in-memory hash table when it is flushed to
+** disk. If successful, SQLITE_OK is returned and (*piOrigin) set to
+** the queried value. Or, if an error occurs, an error code is returned
+** and the final value of (*piOrigin) is undefined.
+*/
+static int sqlite3Fts5IndexGetOrigin(Fts5Index *p, i64 *piOrigin){
+  Fts5Structure *pStruct;
+  pStruct = fts5StructureRead(p);
+  if( pStruct ){
+    *piOrigin = pStruct->nOriginCntr;
+    fts5StructureRelease(pStruct);
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** Buffer pPg contains a page of a tombstone hash table - one of nPg pages
+** associated with the same segment. This function adds rowid iRowid to
+** the hash table. The caller is required to guarantee that there is at
+** least one free slot on the page.
+**
+** If parameter bForce is false and the hash table is deemed to be full
+** (more than half of the slots are occupied), then non-zero is returned
+** and iRowid not inserted. Or, if bForce is true or if the hash table page
+** is not full, iRowid is inserted and zero returned.
+*/
+static int fts5IndexTombstoneAddToPage(
+  Fts5Data *pPg,
+  int bForce,
+  int nPg,
+  u64 iRowid
+){
+  const int szKey = TOMBSTONE_KEYSIZE(pPg);
+  const int nSlot = TOMBSTONE_NSLOT(pPg);
+  const int nElem = fts5GetU32(&pPg->p[4]);
+  int iSlot = (iRowid / nPg) % nSlot;
+  int nCollide = nSlot;
+
+  if( szKey==4 && iRowid>0xFFFFFFFF ) return 2;
+  if( iRowid==0 ){
+    pPg->p[1] = 0x01;
+    return 0;
+  }
+
+  if( bForce==0 && nElem>=(nSlot/2) ){
+    return 1;
+  }
+
+  fts5PutU32(&pPg->p[4], nElem+1);
+  if( szKey==4 ){
+    u32 *aSlot = (u32*)&pPg->p[8];
+    while( aSlot[iSlot] ){
+      iSlot = (iSlot + 1) % nSlot;
+      if( nCollide--==0 ) return 0;
+    }
+    fts5PutU32((u8*)&aSlot[iSlot], (u32)iRowid);
+  }else{
+    u64 *aSlot = (u64*)&pPg->p[8];
+    while( aSlot[iSlot] ){
+      iSlot = (iSlot + 1) % nSlot;
+      if( nCollide--==0 ) return 0;
+    }
+    fts5PutU64((u8*)&aSlot[iSlot], iRowid);
+  }
+
+  return 0;
+}
+
+/*
+** This function attempts to build a new hash containing all the keys
+** currently in the tombstone hash table for segment pSeg. The new
+** hash will be stored in the nOut buffers passed in array apOut[].
+** All pages of the new hash use key-size szKey (4 or 8).
+**
+** Return 0 if the hash is successfully rebuilt into the nOut pages.
+** Or non-zero if it is not (because one page became overfull). In this
+** case the caller should retry with a larger nOut parameter.
+**
+** Parameter pData1 is page iPg1 of the hash table being rebuilt.
+*/
+static int fts5IndexTombstoneRehash(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,     /* Segment to rebuild hash of */
+  Fts5Data *pData1,               /* One page of current hash - or NULL */
+  int iPg1,                       /* Which page of the current hash is pData1 */
+  int szKey,                      /* 4 or 8, the keysize */
+  int nOut,                       /* Number of output pages */
+  Fts5Data **apOut                /* Array of output hash pages */
+){
+  int ii;
+  int res = 0;
+
+  /* Initialize the headers of all the output pages */
+  for(ii=0; ii<nOut; ii++){
+    apOut[ii]->p[0] = szKey;
+    fts5PutU32(&apOut[ii]->p[4], 0);
+  }
+
+  /* Loop through the current pages of the hash table. */
+  for(ii=0; res==0 && ii<pSeg->nPgTombstone; ii++){
+    Fts5Data *pData = 0;          /* Page ii of the current hash table */
+    Fts5Data *pFree = 0;          /* Free this at the end of the loop */
+
+    if( iPg1==ii ){
+      pData = pData1;
+    }else{
+      pFree = pData = fts5DataRead(p, FTS5_TOMBSTONE_ROWID(pSeg->iSegid, ii));
+    }
+
+    if( pData ){
+      int szKeyIn = TOMBSTONE_KEYSIZE(pData);
+      int nSlotIn = (pData->nn - 8) / szKeyIn;
+      int iIn;
+      for(iIn=0; iIn<nSlotIn; iIn++){
+        u64 iVal = 0;
+
+        /* Read the value from slot iIn of the input page into iVal. */
+        if( szKeyIn==4 ){
+          u32 *aSlot = (u32*)&pData->p[8];
+          if( aSlot[iIn] ) iVal = fts5GetU32((u8*)&aSlot[iIn]);
+        }else{
+          u64 *aSlot = (u64*)&pData->p[8];
+          if( aSlot[iIn] ) iVal = fts5GetU64((u8*)&aSlot[iIn]);
+        }
+
+        /* If iVal is not 0 at this point, insert it into the new hash table */
+        if( iVal ){
+          Fts5Data *pPg = apOut[(iVal % nOut)];
+          res = fts5IndexTombstoneAddToPage(pPg, 0, nOut, iVal);
+          if( res ) break;
+        }
+      }
+
+      /* If this is page 0 of the old hash, copy the rowid-0-flag from the
+      ** old hash to the new.  */
+      if( ii==0 ){
+        apOut[0]->p[1] = pData->p[1];
+      }
+    }
+    fts5DataRelease(pFree);
+  }
+
+  return res;
+}
+
+/*
+** This is called to rebuild the hash table belonging to segment pSeg.
+** If parameter pData1 is not NULL, then one page of the existing hash table
+** has already been loaded - pData1, which is page iPg1. The key-size for
+** the new hash table is szKey (4 or 8).
+**
+** If successful, the new hash table is not written to disk. Instead,
+** output parameter (*pnOut) is set to the number of pages in the new
+** hash table, and (*papOut) to point to an array of buffers containing
+** the new page data.
+**
+** If an error occurs, an error code is left in the Fts5Index object and
+** both output parameters set to 0 before returning.
+*/
+static void fts5IndexTombstoneRebuild(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,     /* Segment to rebuild hash of */
+  Fts5Data *pData1,               /* One page of current hash - or NULL */
+  int iPg1,                       /* Which page of the current hash is pData1 */
+  int szKey,                      /* 4 or 8, the keysize */
+  int *pnOut,                     /* OUT: Number of output pages */
+  Fts5Data ***papOut              /* OUT: Output hash pages */
+){
+  const int MINSLOT = 32;
+  int nSlotPerPage = MAX(MINSLOT, (p->pConfig->pgsz - 8) / szKey);
+  int nSlot = 0;                  /* Number of slots in each output page */
+  int nOut = 0;
+
+  /* Figure out how many output pages (nOut) and how many slots per
+  ** page (nSlot).  There are three possibilities:
+  **
+  **   1. The hash table does not yet exist. In this case the new hash
+  **      table will consist of a single page with MINSLOT slots.
+  **
+  **   2. The hash table exists but is currently a single page. In this
+  **      case an attempt is made to grow the page to accommodate the new
+  **      entry. The page is allowed to grow up to nSlotPerPage (see above)
+  **      slots.
+  **
+  **   3. The hash table already consists of more than one page, or of
+  **      a single page already so large that it cannot be grown. In this
+  **      case the new hash consists of (nPg*2+1) pages of nSlotPerPage
+  **      slots each, where nPg is the current number of pages in the
+  **      hash table.
+  */
+  if( pSeg->nPgTombstone==0 ){
+    /* Case 1. */
+    nOut = 1;
+    nSlot = MINSLOT;
+  }else if( pSeg->nPgTombstone==1 ){
+    /* Case 2. */
+    int nElem = (int)fts5GetU32(&pData1->p[4]);
+    assert( pData1 && iPg1==0 );
+    nOut = 1;
+    nSlot = MAX(nElem*4, MINSLOT);
+    if( nSlot>nSlotPerPage ) nOut = 0;
+  }
+  if( nOut==0 ){
+    /* Case 3. */
+    nOut = (pSeg->nPgTombstone * 2 + 1);
+    nSlot = nSlotPerPage;
+  }
+
+  /* Allocate the required array and output pages */
+  while( 1 ){
+    int res = 0;
+    int ii = 0;
+    int szPage = 0;
+    Fts5Data **apOut = 0;
+
+    /* Allocate space for the new hash table */
+    assert( nSlot>=MINSLOT );
+    apOut = (Fts5Data**)sqlite3Fts5MallocZero(&p->rc, sizeof(Fts5Data*) * nOut);
+    szPage = 8 + nSlot*szKey;
+    for(ii=0; ii<nOut; ii++){
+      Fts5Data *pNew = (Fts5Data*)sqlite3Fts5MallocZero(&p->rc,
+          sizeof(Fts5Data)+szPage
+      );
+      if( pNew ){
+        pNew->nn = szPage;
+        pNew->p = (u8*)&pNew[1];
+        apOut[ii] = pNew;
+      }
+    }
+
+    /* Rebuild the hash table. */
+    if( p->rc==SQLITE_OK ){
+      res = fts5IndexTombstoneRehash(p, pSeg, pData1, iPg1, szKey, nOut, apOut);
+    }
+    if( res==0 ){
+      if( p->rc ){
+        fts5IndexFreeArray(apOut, nOut);
+        apOut = 0;
+        nOut = 0;
+      }
+      *pnOut = nOut;
+      *papOut = apOut;
+      break;
+    }
+
+    /* If control flows to here, it was not possible to rebuild the hash
+    ** table. Free all buffers and then try again with more pages. */
+    assert( p->rc==SQLITE_OK );
+    fts5IndexFreeArray(apOut, nOut);
+    nSlot = nSlotPerPage;
+    nOut = nOut*2 + 1;
+  }
+}
+
+
+/*
+** Add a tombstone for rowid iRowid to segment pSeg.
+*/
+static void fts5IndexTombstoneAdd(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,
+  u64 iRowid
+){
+  Fts5Data *pPg = 0;
+  int iPg = -1;
+  int szKey = 0;
+  int nHash = 0;
+  Fts5Data **apHash = 0;
+
+  p->nContentlessDelete++;
+
+  if( pSeg->nPgTombstone>0 ){
+    iPg = iRowid % pSeg->nPgTombstone;
+    pPg = fts5DataRead(p, FTS5_TOMBSTONE_ROWID(pSeg->iSegid,iPg));
+    if( pPg==0 ){
+      assert( p->rc!=SQLITE_OK );
+      return;
+    }
+
+    if( 0==fts5IndexTombstoneAddToPage(pPg, 0, pSeg->nPgTombstone, iRowid) ){
+      fts5DataWrite(p, FTS5_TOMBSTONE_ROWID(pSeg->iSegid,iPg), pPg->p, pPg->nn);
+      fts5DataRelease(pPg);
+      return;
+    }
+  }
+
+  /* Have to rebuild the hash table. First figure out the key-size (4 or 8). */
+  szKey = pPg ? TOMBSTONE_KEYSIZE(pPg) : 4;
+  if( iRowid>0xFFFFFFFF ) szKey = 8;
+
+  /* Rebuild the hash table */
+  fts5IndexTombstoneRebuild(p, pSeg, pPg, iPg, szKey, &nHash, &apHash);
+  assert( p->rc==SQLITE_OK || (nHash==0 && apHash==0) );
+
+  /* If all has succeeded, write the new rowid into one of the new hash
+  ** table pages, then write them all out to disk. */
+  if( nHash ){
+    int ii = 0;
+    fts5IndexTombstoneAddToPage(apHash[iRowid % nHash], 1, nHash, iRowid);
+    for(ii=0; ii<nHash; ii++){
+      i64 iTombstoneRowid = FTS5_TOMBSTONE_ROWID(pSeg->iSegid, ii);
+      fts5DataWrite(p, iTombstoneRowid, apHash[ii]->p, apHash[ii]->nn);
+    }
+    pSeg->nPgTombstone = nHash;
+    fts5StructureWrite(p, p->pStruct);
+  }
+
+  fts5DataRelease(pPg);
+  fts5IndexFreeArray(apHash, nHash);
+}
+
+/*
+** Add iRowid to the tombstone list of the segment or segments that contain
+** rows from origin iOrigin. Return SQLITE_OK if successful, or an SQLite
+** error code otherwise.
+*/
+static int sqlite3Fts5IndexContentlessDelete(Fts5Index *p, i64 iOrigin, i64 iRowid){
+  Fts5Structure *pStruct;
+  pStruct = fts5StructureRead(p);
+  if( pStruct ){
+    int bFound = 0;               /* True after pSeg->nEntryTombstone incr. */
+    int iLvl;
+    for(iLvl=pStruct->nLevel-1; iLvl>=0; iLvl--){
+      int iSeg;
+      for(iSeg=pStruct->aLevel[iLvl].nSeg-1; iSeg>=0; iSeg--){
+        Fts5StructureSegment *pSeg = &pStruct->aLevel[iLvl].aSeg[iSeg];
+        if( pSeg->iOrigin1<=(u64)iOrigin && pSeg->iOrigin2>=(u64)iOrigin ){
+          if( bFound==0 ){
+            pSeg->nEntryTombstone++;
+            bFound = 1;
+          }
+          fts5IndexTombstoneAdd(p, pSeg, iRowid);
+        }
+      }
+    }
+    fts5StructureRelease(pStruct);
+  }
+  return fts5IndexReturn(p);
+}
+
+/*************************************************************************
+**************************************************************************
+** Below this point is the implementation of the integrity-check
+** functionality.
+*/
+
+/*
+** Return a simple checksum value based on the arguments.
+*/
+static u64 sqlite3Fts5IndexEntryCksum(
+  i64 iRowid,
+  int iCol,
+  int iPos,
+  int iIdx,
+  const char *pTerm,
+  int nTerm
+){
+  int i;
+  u64 ret = iRowid;
+  ret += (ret<<3) + iCol;
+  ret += (ret<<3) + iPos;
+  if( iIdx>=0 ) ret += (ret<<3) + (FTS5_MAIN_PREFIX + iIdx);
+  for(i=0; i<nTerm; i++) ret += (ret<<3) + pTerm[i];
+  return ret;
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** This function is purely an internal test. It does not contribute to
+** FTS functionality, or even the integrity-check, in any way.
+**
+** Instead, it tests that the same set of pgno/rowid combinations are
+** visited regardless of whether the doclist-index identified by parameters
+** iSegid/iLeaf is iterated in forwards or reverse order.
+*/
+static void fts5TestDlidxReverse(
+  Fts5Index *p,
+  int iSegid,                     /* Segment id to load from */
+  int iLeaf                       /* Load doclist-index for this leaf */
+){
+  Fts5DlidxIter *pDlidx = 0;
+  u64 cksum1 = 13;
+  u64 cksum2 = 13;
+
+  for(pDlidx=fts5DlidxIterInit(p, 0, iSegid, iLeaf);
+      fts5DlidxIterEof(p, pDlidx)==0;
+      fts5DlidxIterNext(p, pDlidx)
+  ){
+    i64 iRowid = fts5DlidxIterRowid(pDlidx);
+    int pgno = fts5DlidxIterPgno(pDlidx);
+    assert( pgno>iLeaf );
+    cksum1 += iRowid + ((i64)pgno<<32);
+  }
+  fts5DlidxIterFree(pDlidx);
+  pDlidx = 0;
+
+  for(pDlidx=fts5DlidxIterInit(p, 1, iSegid, iLeaf);
+      fts5DlidxIterEof(p, pDlidx)==0;
+      fts5DlidxIterPrev(p, pDlidx)
+  ){
+    i64 iRowid = fts5DlidxIterRowid(pDlidx);
+    int pgno = fts5DlidxIterPgno(pDlidx);
+    assert( fts5DlidxIterPgno(pDlidx)>iLeaf );
+    cksum2 += iRowid + ((i64)pgno<<32);
+  }
+  fts5DlidxIterFree(pDlidx);
+  pDlidx = 0;
+
+  if( p->rc==SQLITE_OK && cksum1!=cksum2 ) p->rc = FTS5_CORRUPT;
+}
+
+static int fts5QueryCksum(
+  Fts5Index *p,                   /* Fts5 index object */
+  int iIdx,
+  const char *z,                  /* Index key to query for */
+  int n,                          /* Size of index key in bytes */
+  int flags,                      /* Flags for Fts5IndexQuery */
+  u64 *pCksum                     /* IN/OUT: Checksum value */
+){
+  int eDetail = p->pConfig->eDetail;
+  u64 cksum = *pCksum;
+  Fts5IndexIter *pIter = 0;
+  int rc = sqlite3Fts5IndexQuery(
+      p, z, n, (flags | FTS5INDEX_QUERY_NOTOKENDATA), 0, &pIter
+  );
+
+  while( rc==SQLITE_OK && ALWAYS(pIter!=0) && 0==sqlite3Fts5IterEof(pIter) ){
+    i64 rowid = pIter->iRowid;
+
+    if( eDetail==FTS5_DETAIL_NONE ){
+      cksum ^= sqlite3Fts5IndexEntryCksum(rowid, 0, 0, iIdx, z, n);
+    }else{
+      Fts5PoslistReader sReader;
+      for(sqlite3Fts5PoslistReaderInit(pIter->pData, pIter->nData, &sReader);
+          sReader.bEof==0;
+          sqlite3Fts5PoslistReaderNext(&sReader)
+      ){
+        int iCol = FTS5_POS2COLUMN(sReader.iPos);
+        int iOff = FTS5_POS2OFFSET(sReader.iPos);
+        cksum ^= sqlite3Fts5IndexEntryCksum(rowid, iCol, iOff, iIdx, z, n);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5IterNext(pIter);
+    }
+  }
+  fts5IterClose(pIter);
+
+  *pCksum = cksum;
+  return rc;
+}
+
+/*
+** Check if buffer z[], size n bytes, contains as series of valid utf-8
+** encoded codepoints. If so, return 0. Otherwise, if the buffer does not
+** contain valid utf-8, return non-zero.
+*/
+static int fts5TestUtf8(const char *z, int n){
+  int i = 0;
+  assert_nc( n>0 );
+  while( i<n ){
+    if( (z[i] & 0x80)==0x00 ){
+      i++;
+    }else
+    if( (z[i] & 0xE0)==0xC0 ){
+      if( i+1>=n || (z[i+1] & 0xC0)!=0x80 ) return 1;
+      i += 2;
+    }else
+    if( (z[i] & 0xF0)==0xE0 ){
+      if( i+2>=n || (z[i+1] & 0xC0)!=0x80 || (z[i+2] & 0xC0)!=0x80 ) return 1;
+      i += 3;
+    }else
+    if( (z[i] & 0xF8)==0xF0 ){
+      if( i+3>=n || (z[i+1] & 0xC0)!=0x80 || (z[i+2] & 0xC0)!=0x80 ) return 1;
+      if( (z[i+2] & 0xC0)!=0x80 ) return 1;
+      i += 3;
+    }else{
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
+/*
+** This function is also purely an internal test. It does not contribute to
+** FTS functionality, or even the integrity-check, in any way.
+*/
+static void fts5TestTerm(
+  Fts5Index *p,
+  Fts5Buffer *pPrev,              /* Previous term */
+  const char *z, int n,           /* Possibly new term to test */
+  u64 expected,
+  u64 *pCksum
+){
+  int rc = p->rc;
+  if( pPrev->n==0 ){
+    fts5BufferSet(&rc, pPrev, n, (const u8*)z);
+  }else
+  if( rc==SQLITE_OK && (pPrev->n!=n || memcmp(pPrev->p, z, n)) ){
+    u64 cksum3 = *pCksum;
+    const char *zTerm = (const char*)&pPrev->p[1];  /* term sans prefix-byte */
+    int nTerm = pPrev->n-1;            /* Size of zTerm in bytes */
+    int iIdx = (pPrev->p[0] - FTS5_MAIN_PREFIX);
+    int flags = (iIdx==0 ? 0 : FTS5INDEX_QUERY_PREFIX);
+    u64 ck1 = 0;
+    u64 ck2 = 0;
+
+    /* Check that the results returned for ASC and DESC queries are
+    ** the same. If not, call this corruption.  */
+    rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, flags, &ck1);
+    if( rc==SQLITE_OK ){
+      int f = flags|FTS5INDEX_QUERY_DESC;
+      rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, f, &ck2);
+    }
+    if( rc==SQLITE_OK && ck1!=ck2 ) rc = FTS5_CORRUPT;
+
+    /* If this is a prefix query, check that the results returned if the
+    ** the index is disabled are the same. In both ASC and DESC order.
+    **
+    ** This check may only be performed if the hash table is empty. This
+    ** is because the hash table only supports a single scan query at
+    ** a time, and the multi-iter loop from which this function is called
+    ** is already performing such a scan.
+    **
+    ** Also only do this if buffer zTerm contains nTerm bytes of valid
+    ** utf-8. Otherwise, the last part of the buffer contents might contain
+    ** a non-utf-8 sequence that happens to be a prefix of a valid utf-8
+    ** character stored in the main fts index, which will cause the
+    ** test to fail.  */
+    if( p->nPendingData==0 && 0==fts5TestUtf8(zTerm, nTerm) ){
+      if( iIdx>0 && rc==SQLITE_OK ){
+        int f = flags|FTS5INDEX_QUERY_TEST_NOIDX;
+        ck2 = 0;
+        rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, f, &ck2);
+        if( rc==SQLITE_OK && ck1!=ck2 ) rc = FTS5_CORRUPT;
+      }
+      if( iIdx>0 && rc==SQLITE_OK ){
+        int f = flags|FTS5INDEX_QUERY_TEST_NOIDX|FTS5INDEX_QUERY_DESC;
+        ck2 = 0;
+        rc = fts5QueryCksum(p, iIdx, zTerm, nTerm, f, &ck2);
+        if( rc==SQLITE_OK && ck1!=ck2 ) rc = FTS5_CORRUPT;
+      }
+    }
+
+    cksum3 ^= ck1;
+    fts5BufferSet(&rc, pPrev, n, (const u8*)z);
+
+    if( rc==SQLITE_OK && cksum3!=expected ){
+      rc = FTS5_CORRUPT;
+    }
+    *pCksum = cksum3;
+  }
+  p->rc = rc;
+}
+
+#else
+# define fts5TestDlidxReverse(x,y,z)
+# define fts5TestTerm(u,v,w,x,y,z)
+#endif
+
+/*
+** Check that:
+**
+**   1) All leaves of pSeg between iFirst and iLast (inclusive) exist and
+**      contain zero terms.
+**   2) All leaves of pSeg between iNoRowid and iLast (inclusive) exist and
+**      contain zero rowids.
+*/
+static void fts5IndexIntegrityCheckEmpty(
+  Fts5Index *p,
+  Fts5StructureSegment *pSeg,     /* Segment to check internal consistency */
+  int iFirst,
+  int iNoRowid,
+  int iLast
+){
+  int i;
+
+  /* Now check that the iter.nEmpty leaves following the current leaf
+  ** (a) exist and (b) contain no terms. */
+  for(i=iFirst; p->rc==SQLITE_OK && i<=iLast; i++){
+    Fts5Data *pLeaf = fts5DataRead(p, FTS5_SEGMENT_ROWID(pSeg->iSegid, i));
+    if( pLeaf ){
+      if( !fts5LeafIsTermless(pLeaf) ) p->rc = FTS5_CORRUPT;
+      if( i>=iNoRowid && 0!=fts5LeafFirstRowidOff(pLeaf) ) p->rc = FTS5_CORRUPT;
+    }
+    fts5DataRelease(pLeaf);
+  }
+}
+
+static void fts5IntegrityCheckPgidx(Fts5Index *p, Fts5Data *pLeaf){
+  i64 iTermOff = 0;
+  int ii;
+
+  Fts5Buffer buf1 = {0,0,0};
+  Fts5Buffer buf2 = {0,0,0};
+
+  ii = pLeaf->szLeaf;
+  while( ii<pLeaf->nn && p->rc==SQLITE_OK ){
+    int res;
+    i64 iOff;
+    int nIncr;
+
+    ii += fts5GetVarint32(&pLeaf->p[ii], nIncr);
+    iTermOff += nIncr;
+    iOff = iTermOff;
+
+    if( iOff>=pLeaf->szLeaf ){
+      p->rc = FTS5_CORRUPT;
+    }else if( iTermOff==nIncr ){
+      int nByte;
+      iOff += fts5GetVarint32(&pLeaf->p[iOff], nByte);
+      if( (iOff+nByte)>pLeaf->szLeaf ){
+        p->rc = FTS5_CORRUPT;
+      }else{
+        fts5BufferSet(&p->rc, &buf1, nByte, &pLeaf->p[iOff]);
+      }
+    }else{
+      int nKeep, nByte;
+      iOff += fts5GetVarint32(&pLeaf->p[iOff], nKeep);
+      iOff += fts5GetVarint32(&pLeaf->p[iOff], nByte);
+      if( nKeep>buf1.n || (iOff+nByte)>pLeaf->szLeaf ){
+        p->rc = FTS5_CORRUPT;
+      }else{
+        buf1.n = nKeep;
+        fts5BufferAppendBlob(&p->rc, &buf1, nByte, &pLeaf->p[iOff]);
+      }
+
+      if( p->rc==SQLITE_OK ){
+        res = fts5BufferCompare(&buf1, &buf2);
+        if( res<=0 ) p->rc = FTS5_CORRUPT;
+      }
+    }
+    fts5BufferSet(&p->rc, &buf2, buf1.n, buf1.p);
+  }
+
+  fts5BufferFree(&buf1);
+  fts5BufferFree(&buf2);
+}
+
+static void fts5IndexIntegrityCheckSegment(
+  Fts5Index *p,                   /* FTS5 backend object */
+  Fts5StructureSegment *pSeg      /* Segment to check internal consistency */
+){
+  Fts5Config *pConfig = p->pConfig;
+  int bSecureDelete = (pConfig->iVersion==FTS5_CURRENT_VERSION_SECUREDELETE);
+  sqlite3_stmt *pStmt = 0;
+  int rc2;
+  int iIdxPrevLeaf = pSeg->pgnoFirst-1;
+  int iDlidxPrevLeaf = pSeg->pgnoLast;
+
+  if( pSeg->pgnoFirst==0 ) return;
+
+  fts5IndexPrepareStmt(p, &pStmt, sqlite3_mprintf(
+      "SELECT segid, term, (pgno>>1), (pgno&1) FROM %Q.'%q_idx' WHERE segid=%d "
+      "ORDER BY 1, 2",
+      pConfig->zDb, pConfig->zName, pSeg->iSegid
+  ));
+
+  /* Iterate through the b-tree hierarchy.  */
+  while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
+    i64 iRow;                     /* Rowid for this leaf */
+    Fts5Data *pLeaf;              /* Data for this leaf */
+
+    const char *zIdxTerm = (const char*)sqlite3_column_blob(pStmt, 1);
+    int nIdxTerm = sqlite3_column_bytes(pStmt, 1);
+    int iIdxLeaf = sqlite3_column_int(pStmt, 2);
+    int bIdxDlidx = sqlite3_column_int(pStmt, 3);
+
+    /* If the leaf in question has already been trimmed from the segment,
+    ** ignore this b-tree entry. Otherwise, load it into memory. */
+    if( iIdxLeaf<pSeg->pgnoFirst ) continue;
+    iRow = FTS5_SEGMENT_ROWID(pSeg->iSegid, iIdxLeaf);
+    pLeaf = fts5LeafRead(p, iRow);
+    if( pLeaf==0 ) break;
+
+    /* Check that the leaf contains at least one term, and that it is equal
+    ** to or larger than the split-key in zIdxTerm.  Also check that if there
+    ** is also a rowid pointer within the leaf page header, it points to a
+    ** location before the term.  */
+    if( pLeaf->nn<=pLeaf->szLeaf ){
+
+      if( nIdxTerm==0
+       && pConfig->iVersion==FTS5_CURRENT_VERSION_SECUREDELETE
+       && pLeaf->nn==pLeaf->szLeaf
+       && pLeaf->nn==4
+      ){
+        /* special case - the very first page in a segment keeps its %_idx
+        ** entry even if all the terms are removed from it by secure-delete
+        ** operations. */
+      }else{
+        p->rc = FTS5_CORRUPT;
+      }
+
+    }else{
+      int iOff;                   /* Offset of first term on leaf */
+      int iRowidOff;              /* Offset of first rowid on leaf */
+      int nTerm;                  /* Size of term on leaf in bytes */
+      int res;                    /* Comparison of term and split-key */
+
+      iOff = fts5LeafFirstTermOff(pLeaf);
+      iRowidOff = fts5LeafFirstRowidOff(pLeaf);
+      if( iRowidOff>=iOff || iOff>=pLeaf->szLeaf ){
+        p->rc = FTS5_CORRUPT;
+      }else{
+        iOff += fts5GetVarint32(&pLeaf->p[iOff], nTerm);
+        res = fts5Memcmp(&pLeaf->p[iOff], zIdxTerm, MIN(nTerm, nIdxTerm));
+        if( res==0 ) res = nTerm - nIdxTerm;
+        if( res<0 ) p->rc = FTS5_CORRUPT;
+      }
+
+      fts5IntegrityCheckPgidx(p, pLeaf);
+    }
+    fts5DataRelease(pLeaf);
+    if( p->rc ) break;
+
+    /* Now check that the iter.nEmpty leaves following the current leaf
+    ** (a) exist and (b) contain no terms. */
+    fts5IndexIntegrityCheckEmpty(
+        p, pSeg, iIdxPrevLeaf+1, iDlidxPrevLeaf+1, iIdxLeaf-1
+    );
+    if( p->rc ) break;
+
+    /* If there is a doclist-index, check that it looks right. */
+    if( bIdxDlidx ){
+      Fts5DlidxIter *pDlidx = 0;  /* For iterating through doclist index */
+      int iPrevLeaf = iIdxLeaf;
+      int iSegid = pSeg->iSegid;
+      int iPg = 0;
+      i64 iKey;
+
+      for(pDlidx=fts5DlidxIterInit(p, 0, iSegid, iIdxLeaf);
+          fts5DlidxIterEof(p, pDlidx)==0;
+          fts5DlidxIterNext(p, pDlidx)
+      ){
+
+        /* Check any rowid-less pages that occur before the current leaf. */
+        for(iPg=iPrevLeaf+1; iPg<fts5DlidxIterPgno(pDlidx); iPg++){
+          iKey = FTS5_SEGMENT_ROWID(iSegid, iPg);
+          pLeaf = fts5DataRead(p, iKey);
+          if( pLeaf ){
+            if( fts5LeafFirstRowidOff(pLeaf)!=0 ) p->rc = FTS5_CORRUPT;
+            fts5DataRelease(pLeaf);
+          }
+        }
+        iPrevLeaf = fts5DlidxIterPgno(pDlidx);
+
+        /* Check that the leaf page indicated by the iterator really does
+        ** contain the rowid suggested by the same. */
+        iKey = FTS5_SEGMENT_ROWID(iSegid, iPrevLeaf);
+        pLeaf = fts5DataRead(p, iKey);
+        if( pLeaf ){
+          i64 iRowid;
+          int iRowidOff = fts5LeafFirstRowidOff(pLeaf);
+          ASSERT_SZLEAF_OK(pLeaf);
+          if( iRowidOff>=pLeaf->szLeaf ){
+            p->rc = FTS5_CORRUPT;
+          }else if( bSecureDelete==0 || iRowidOff>0 ){
+            i64 iDlRowid = fts5DlidxIterRowid(pDlidx);
+            fts5GetVarint(&pLeaf->p[iRowidOff], (u64*)&iRowid);
+            if( iRowid<iDlRowid || (bSecureDelete==0 && iRowid!=iDlRowid) ){
+              p->rc = FTS5_CORRUPT;
+            }
+          }
+          fts5DataRelease(pLeaf);
+        }
+      }
+
+      iDlidxPrevLeaf = iPg;
+      fts5DlidxIterFree(pDlidx);
+      fts5TestDlidxReverse(p, iSegid, iIdxLeaf);
+    }else{
+      iDlidxPrevLeaf = pSeg->pgnoLast;
+      /* TODO: Check there is no doclist index */
+    }
+
+    iIdxPrevLeaf = iIdxLeaf;
+  }
+
+  rc2 = sqlite3_finalize(pStmt);
+  if( p->rc==SQLITE_OK ) p->rc = rc2;
+
+  /* Page iter.iLeaf must now be the rightmost leaf-page in the segment */
+#if 0
+  if( p->rc==SQLITE_OK && iter.iLeaf!=pSeg->pgnoLast ){
+    p->rc = FTS5_CORRUPT;
+  }
+#endif
+}
+
+
+/*
+** Run internal checks to ensure that the FTS index (a) is internally
+** consistent and (b) contains entries for which the XOR of the checksums
+** as calculated by sqlite3Fts5IndexEntryCksum() is cksum.
+**
+** Return SQLITE_CORRUPT if any of the internal checks fail, or if the
+** checksum does not match. Return SQLITE_OK if all checks pass without
+** error, or some other SQLite error code if another error (e.g. OOM)
+** occurs.
+*/
+static int sqlite3Fts5IndexIntegrityCheck(Fts5Index *p, u64 cksum, int bUseCksum){
+  int eDetail = p->pConfig->eDetail;
+  u64 cksum2 = 0;                 /* Checksum based on contents of indexes */
+  Fts5Buffer poslist = {0,0,0};   /* Buffer used to hold a poslist */
+  Fts5Iter *pIter;                /* Used to iterate through entire index */
+  Fts5Structure *pStruct;         /* Index structure */
+  int iLvl, iSeg;
+
+#ifdef SQLITE_DEBUG
+  /* Used by extra internal tests only run if NDEBUG is not defined */
+  u64 cksum3 = 0;                 /* Checksum based on contents of indexes */
+  Fts5Buffer term = {0,0,0};      /* Buffer used to hold most recent term */
+#endif
+  const int flags = FTS5INDEX_QUERY_NOOUTPUT;
+
+  /* Load the FTS index structure */
+  pStruct = fts5StructureRead(p);
+  if( pStruct==0 ){
+    assert( p->rc!=SQLITE_OK );
+    return fts5IndexReturn(p);
+  }
+
+  /* Check that the internal nodes of each segment match the leaves */
+  for(iLvl=0; iLvl<pStruct->nLevel; iLvl++){
+    for(iSeg=0; iSeg<pStruct->aLevel[iLvl].nSeg; iSeg++){
+      Fts5StructureSegment *pSeg = &pStruct->aLevel[iLvl].aSeg[iSeg];
+      fts5IndexIntegrityCheckSegment(p, pSeg);
+    }
+  }
+
+  /* The cksum argument passed to this function is a checksum calculated
+  ** based on all expected entries in the FTS index (including prefix index
+  ** entries). This block checks that a checksum calculated based on the
+  ** actual contents of FTS index is identical.
+  **
+  ** Two versions of the same checksum are calculated. The first (stack
+  ** variable cksum2) based on entries extracted from the full-text index
+  ** while doing a linear scan of each individual index in turn.
+  **
+  ** As each term visited by the linear scans, a separate query for the
+  ** same term is performed. cksum3 is calculated based on the entries
+  ** extracted by these queries.
+  */
+  for(fts5MultiIterNew(p, pStruct, flags, 0, 0, 0, -1, 0, &pIter);
+      fts5MultiIterEof(p, pIter)==0;
+      fts5MultiIterNext(p, pIter, 0, 0)
+  ){
+    int n;                      /* Size of term in bytes */
+    i64 iPos = 0;               /* Position read from poslist */
+    int iOff = 0;               /* Offset within poslist */
+    i64 iRowid = fts5MultiIterRowid(pIter);
+    char *z = (char*)fts5MultiIterTerm(pIter, &n);
+
+    /* If this is a new term, query for it. Update cksum3 with the results. */
+    fts5TestTerm(p, &term, z, n, cksum2, &cksum3);
+    if( p->rc ) break;
+
+    if( eDetail==FTS5_DETAIL_NONE ){
+      if( 0==fts5MultiIterIsEmpty(p, pIter) ){
+        cksum2 ^= sqlite3Fts5IndexEntryCksum(iRowid, 0, 0, -1, z, n);
+      }
+    }else{
+      poslist.n = 0;
+      fts5SegiterPoslist(p, &pIter->aSeg[pIter->aFirst[1].iFirst], 0, &poslist);
+      fts5BufferAppendBlob(&p->rc, &poslist, 4, (const u8*)"\0\0\0\0");
+      while( 0==sqlite3Fts5PoslistNext64(poslist.p, poslist.n, &iOff, &iPos) ){
+        int iCol = FTS5_POS2COLUMN(iPos);
+        int iTokOff = FTS5_POS2OFFSET(iPos);
+        cksum2 ^= sqlite3Fts5IndexEntryCksum(iRowid, iCol, iTokOff, -1, z, n);
+      }
+    }
+  }
+  fts5TestTerm(p, &term, 0, 0, cksum2, &cksum3);
+
+  fts5MultiIterFree(pIter);
+  if( p->rc==SQLITE_OK && bUseCksum && cksum!=cksum2 ) p->rc = FTS5_CORRUPT;
+
+  fts5StructureRelease(pStruct);
+#ifdef SQLITE_DEBUG
+  fts5BufferFree(&term);
+#endif
+  fts5BufferFree(&poslist);
+  return fts5IndexReturn(p);
+}
+
+/*************************************************************************
+**************************************************************************
+** Below this point is the implementation of the fts5_decode() scalar
+** function only.
+*/
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** Decode a segment-data rowid from the %_data table. This function is
+** the opposite of macro FTS5_SEGMENT_ROWID().
+*/
+static void fts5DecodeRowid(
+  i64 iRowid,                     /* Rowid from %_data table */
+  int *pbTombstone,               /* OUT: Tombstone hash flag */
+  int *piSegid,                   /* OUT: Segment id */
+  int *pbDlidx,                   /* OUT: Dlidx flag */
+  int *piHeight,                  /* OUT: Height */
+  int *piPgno                     /* OUT: Page number */
+){
+  *piPgno = (int)(iRowid & (((i64)1 << FTS5_DATA_PAGE_B) - 1));
+  iRowid >>= FTS5_DATA_PAGE_B;
+
+  *piHeight = (int)(iRowid & (((i64)1 << FTS5_DATA_HEIGHT_B) - 1));
+  iRowid >>= FTS5_DATA_HEIGHT_B;
+
+  *pbDlidx = (int)(iRowid & 0x0001);
+  iRowid >>= FTS5_DATA_DLI_B;
+
+  *piSegid = (int)(iRowid & (((i64)1 << FTS5_DATA_ID_B) - 1));
+  iRowid >>= FTS5_DATA_ID_B;
+
+  *pbTombstone = (int)(iRowid & 0x0001);
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+static void fts5DebugRowid(int *pRc, Fts5Buffer *pBuf, i64 iKey){
+  int iSegid, iHeight, iPgno, bDlidx, bTomb;     /* Rowid compenents */
+  fts5DecodeRowid(iKey, &bTomb, &iSegid, &bDlidx, &iHeight, &iPgno);
+
+  if( iSegid==0 ){
+    if( iKey==FTS5_AVERAGES_ROWID ){
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "{averages} ");
+    }else{
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "{structure}");
+    }
+  }
+  else{
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "{%s%ssegid=%d h=%d pgno=%d}",
+        bDlidx ? "dlidx " : "",
+        bTomb ? "tombstone " : "",
+        iSegid, iHeight, iPgno
+    );
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+static void fts5DebugStructure(
+  int *pRc,                       /* IN/OUT: error code */
+  Fts5Buffer *pBuf,
+  Fts5Structure *p
+){
+  int iLvl, iSeg;                 /* Iterate through levels, segments */
+
+  for(iLvl=0; iLvl<p->nLevel; iLvl++){
+    Fts5StructureLevel *pLvl = &p->aLevel[iLvl];
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf,
+        " {lvl=%d nMerge=%d nSeg=%d", iLvl, pLvl->nMerge, pLvl->nSeg
+    );
+    for(iSeg=0; iSeg<pLvl->nSeg; iSeg++){
+      Fts5StructureSegment *pSeg = &pLvl->aSeg[iSeg];
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " {id=%d leaves=%d..%d",
+          pSeg->iSegid, pSeg->pgnoFirst, pSeg->pgnoLast
+      );
+      if( pSeg->iOrigin1>0 ){
+        sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " origin=%lld..%lld",
+            pSeg->iOrigin1, pSeg->iOrigin2
+        );
+      }
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "}");
+    }
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "}");
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** This is part of the fts5_decode() debugging aid.
+**
+** Arguments pBlob/nBlob contain a serialized Fts5Structure object. This
+** function appends a human-readable representation of the same object
+** to the buffer passed as the second argument.
+*/
+static void fts5DecodeStructure(
+  int *pRc,                       /* IN/OUT: error code */
+  Fts5Buffer *pBuf,
+  const u8 *pBlob, int nBlob
+){
+  int rc;                         /* Return code */
+  Fts5Structure *p = 0;           /* Decoded structure object */
+
+  rc = fts5StructureDecode(pBlob, nBlob, 0, &p);
+  if( rc!=SQLITE_OK ){
+    *pRc = rc;
+    return;
+  }
+
+  fts5DebugStructure(pRc, pBuf, p);
+  fts5StructureRelease(p);
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** This is part of the fts5_decode() debugging aid.
+**
+** Arguments pBlob/nBlob contain an "averages" record. This function
+** appends a human-readable representation of record to the buffer passed
+** as the second argument.
+*/
+static void fts5DecodeAverages(
+  int *pRc,                       /* IN/OUT: error code */
+  Fts5Buffer *pBuf,
+  const u8 *pBlob, int nBlob
+){
+  int i = 0;
+  const char *zSpace = "";
+
+  while( i<nBlob ){
+    u64 iVal;
+    i += sqlite3Fts5GetVarint(&pBlob[i], &iVal);
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, "%s%d", zSpace, (int)iVal);
+    zSpace = " ";
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** Buffer (a/n) is assumed to contain a list of serialized varints. Read
+** each varint and append its string representation to buffer pBuf. Return
+** after either the input buffer is exhausted or a 0 value is read.
+**
+** The return value is the number of bytes read from the input buffer.
+*/
+static int fts5DecodePoslist(int *pRc, Fts5Buffer *pBuf, const u8 *a, int n){
+  int iOff = 0;
+  while( iOff<n ){
+    int iVal;
+    iOff += fts5GetVarint32(&a[iOff], iVal);
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " %d", iVal);
+  }
+  return iOff;
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** The start of buffer (a/n) contains the start of a doclist. The doclist
+** may or may not finish within the buffer. This function appends a text
+** representation of the part of the doclist that is present to buffer
+** pBuf.
+**
+** The return value is the number of bytes read from the input buffer.
+*/
+static int fts5DecodeDoclist(int *pRc, Fts5Buffer *pBuf, const u8 *a, int n){
+  i64 iDocid = 0;
+  int iOff = 0;
+
+  if( n>0 ){
+    iOff = sqlite3Fts5GetVarint(a, (u64*)&iDocid);
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " id=%lld", iDocid);
+  }
+  while( iOff<n ){
+    int nPos;
+    int bDel;
+    iOff += fts5GetPoslistSize(&a[iOff], &nPos, &bDel);
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " nPos=%d%s", nPos, bDel?"*":"");
+    iOff += fts5DecodePoslist(pRc, pBuf, &a[iOff], MIN(n-iOff, nPos));
+    if( iOff<n ){
+      i64 iDelta;
+      iOff += sqlite3Fts5GetVarint(&a[iOff], (u64*)&iDelta);
+      iDocid += iDelta;
+      sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " id=%lld", iDocid);
+    }
+  }
+
+  return iOff;
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** This function is part of the fts5_decode() debugging function. It is
+** only ever used with detail=none tables.
+**
+** Buffer (pData/nData) contains a doclist in the format used by detail=none
+** tables. This function appends a human-readable version of that list to
+** buffer pBuf.
+**
+** If *pRc is other than SQLITE_OK when this function is called, it is a
+** no-op. If an OOM or other error occurs within this function, *pRc is
+** set to an SQLite error code before returning. The final state of buffer
+** pBuf is undefined in this case.
+*/
+static void fts5DecodeRowidList(
+  int *pRc,                       /* IN/OUT: Error code */
+  Fts5Buffer *pBuf,               /* Buffer to append text to */
+  const u8 *pData, int nData      /* Data to decode list-of-rowids from */
+){
+  int i = 0;
+  i64 iRowid = 0;
+
+  while( i<nData ){
+    const char *zApp = "";
+    u64 iVal;
+    i += sqlite3Fts5GetVarint(&pData[i], &iVal);
+    iRowid += iVal;
+
+    if( i<nData && pData[i]==0x00 ){
+      i++;
+      if( i<nData && pData[i]==0x00 ){
+        i++;
+        zApp = "+";
+      }else{
+        zApp = "*";
+      }
+    }
+
+    sqlite3Fts5BufferAppendPrintf(pRc, pBuf, " %lld%s", iRowid, zApp);
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+static void fts5BufferAppendTerm(int *pRc, Fts5Buffer *pBuf, Fts5Buffer *pTerm){
+  int ii;
+  fts5BufferGrow(pRc, pBuf, pTerm->n*2 + 1);
+  if( *pRc==SQLITE_OK ){
+    for(ii=0; ii<pTerm->n; ii++){
+      if( pTerm->p[ii]==0x00 ){
+        pBuf->p[pBuf->n++] = '\\';
+        pBuf->p[pBuf->n++] = '0';
+      }else{
+        pBuf->p[pBuf->n++] = pTerm->p[ii];
+      }
+    }
+    pBuf->p[pBuf->n] = 0x00;
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** The implementation of user-defined scalar function fts5_decode().
+*/
+static void fts5DecodeFunction(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args (always 2) */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  i64 iRowid;                     /* Rowid for record being decoded */
+  int iSegid,iHeight,iPgno,bDlidx;/* Rowid components */
+  int bTomb;
+  const u8 *aBlob; int n;         /* Record to decode */
+  u8 *a = 0;
+  Fts5Buffer s;                   /* Build up text to return here */
+  int rc = SQLITE_OK;             /* Return code */
+  sqlite3_int64 nSpace = 0;
+  int eDetailNone = (sqlite3_user_data(pCtx)!=0);
+
+  assert( nArg==2 );
+  UNUSED_PARAM(nArg);
+  memset(&s, 0, sizeof(Fts5Buffer));
+  iRowid = sqlite3_value_int64(apVal[0]);
+
+  /* Make a copy of the second argument (a blob) in aBlob[]. The aBlob[]
+  ** copy is followed by FTS5_DATA_ZERO_PADDING 0x00 bytes, which prevents
+  ** buffer overreads even if the record is corrupt.  */
+  n = sqlite3_value_bytes(apVal[1]);
+  aBlob = sqlite3_value_blob(apVal[1]);
+  nSpace = n + FTS5_DATA_ZERO_PADDING;
+  a = (u8*)sqlite3Fts5MallocZero(&rc, nSpace);
+  if( a==0 ) goto decode_out;
+  if( n>0 ) memcpy(a, aBlob, n);
+
+  fts5DecodeRowid(iRowid, &bTomb, &iSegid, &bDlidx, &iHeight, &iPgno);
+
+  fts5DebugRowid(&rc, &s, iRowid);
+  if( bDlidx ){
+    Fts5Data dlidx;
+    Fts5DlidxLvl lvl;
+
+    dlidx.p = a;
+    dlidx.nn = n;
+
+    memset(&lvl, 0, sizeof(Fts5DlidxLvl));
+    lvl.pData = &dlidx;
+    lvl.iLeafPgno = iPgno;
+
+    for(fts5DlidxLvlNext(&lvl); lvl.bEof==0; fts5DlidxLvlNext(&lvl)){
+      sqlite3Fts5BufferAppendPrintf(&rc, &s,
+          " %d(%lld)", lvl.iLeafPgno, lvl.iRowid
+      );
+    }
+  }else if( bTomb ){
+    u32 nElem  = fts5GetU32(&a[4]);
+    int szKey = (aBlob[0]==4 || aBlob[0]==8) ? aBlob[0] : 8;
+    int nSlot = (n - 8) / szKey;
+    int ii;
+    sqlite3Fts5BufferAppendPrintf(&rc, &s, " nElem=%d", (int)nElem);
+    if( aBlob[1] ){
+      sqlite3Fts5BufferAppendPrintf(&rc, &s, " 0");
+    }
+    for(ii=0; ii<nSlot; ii++){
+      u64 iVal = 0;
+      if( szKey==4 ){
+        u32 *aSlot = (u32*)&aBlob[8];
+        if( aSlot[ii] ) iVal = fts5GetU32((u8*)&aSlot[ii]);
+      }else{
+        u64 *aSlot = (u64*)&aBlob[8];
+        if( aSlot[ii] ) iVal = fts5GetU64((u8*)&aSlot[ii]);
+      }
+      if( iVal!=0 ){
+        sqlite3Fts5BufferAppendPrintf(&rc, &s, " %lld", (i64)iVal);
+      }
+    }
+  }else if( iSegid==0 ){
+    if( iRowid==FTS5_AVERAGES_ROWID ){
+      fts5DecodeAverages(&rc, &s, a, n);
+    }else{
+      fts5DecodeStructure(&rc, &s, a, n);
+    }
+  }else if( eDetailNone ){
+    Fts5Buffer term;              /* Current term read from page */
+    int szLeaf;
+    int iPgidxOff = szLeaf = fts5GetU16(&a[2]);
+    int iTermOff;
+    int nKeep = 0;
+    int iOff;
+
+    memset(&term, 0, sizeof(Fts5Buffer));
+
+    /* Decode any entries that occur before the first term. */
+    if( szLeaf<n ){
+      iPgidxOff += fts5GetVarint32(&a[iPgidxOff], iTermOff);
+    }else{
+      iTermOff = szLeaf;
+    }
+    fts5DecodeRowidList(&rc, &s, &a[4], iTermOff-4);
+
+    iOff = iTermOff;
+    while( iOff<szLeaf && rc==SQLITE_OK ){
+      int nAppend;
+
+      /* Read the term data for the next term*/
+      iOff += fts5GetVarint32(&a[iOff], nAppend);
+      term.n = nKeep;
+      fts5BufferAppendBlob(&rc, &term, nAppend, &a[iOff]);
+      sqlite3Fts5BufferAppendPrintf(&rc, &s, " term=");
+      fts5BufferAppendTerm(&rc, &s, &term);
+      iOff += nAppend;
+
+      /* Figure out where the doclist for this term ends */
+      if( iPgidxOff<n ){
+        int nIncr;
+        iPgidxOff += fts5GetVarint32(&a[iPgidxOff], nIncr);
+        iTermOff += nIncr;
+      }else{
+        iTermOff = szLeaf;
+      }
+      if( iTermOff>szLeaf ){
+        rc = FTS5_CORRUPT;
+      }else{
+        fts5DecodeRowidList(&rc, &s, &a[iOff], iTermOff-iOff);
+      }
+      iOff = iTermOff;
+      if( iOff<szLeaf ){
+        iOff += fts5GetVarint32(&a[iOff], nKeep);
+      }
+    }
+
+    fts5BufferFree(&term);
+  }else{
+    Fts5Buffer term;              /* Current term read from page */
+    int szLeaf;                   /* Offset of pgidx in a[] */
+    int iPgidxOff;
+    int iPgidxPrev = 0;           /* Previous value read from pgidx */
+    int iTermOff = 0;
+    int iRowidOff = 0;
+    int iOff;
+    int nDoclist;
+
+    memset(&term, 0, sizeof(Fts5Buffer));
+
+    if( n<4 ){
+      sqlite3Fts5BufferSet(&rc, &s, 7, (const u8*)"corrupt");
+      goto decode_out;
+    }else{
+      iRowidOff = fts5GetU16(&a[0]);
+      iPgidxOff = szLeaf = fts5GetU16(&a[2]);
+      if( iPgidxOff<n ){
+        fts5GetVarint32(&a[iPgidxOff], iTermOff);
+      }else if( iPgidxOff>n ){
+        rc = FTS5_CORRUPT;
+        goto decode_out;
+      }
+    }
+
+    /* Decode the position list tail at the start of the page */
+    if( iRowidOff!=0 ){
+      iOff = iRowidOff;
+    }else if( iTermOff!=0 ){
+      iOff = iTermOff;
+    }else{
+      iOff = szLeaf;
+    }
+    if( iOff>n ){
+      rc = FTS5_CORRUPT;
+      goto decode_out;
+    }
+    fts5DecodePoslist(&rc, &s, &a[4], iOff-4);
+
+    /* Decode any more doclist data that appears on the page before the
+    ** first term. */
+    nDoclist = (iTermOff ? iTermOff : szLeaf) - iOff;
+    if( nDoclist+iOff>n ){
+      rc = FTS5_CORRUPT;
+      goto decode_out;
+    }
+    fts5DecodeDoclist(&rc, &s, &a[iOff], nDoclist);
+
+    while( iPgidxOff<n && rc==SQLITE_OK ){
+      int bFirst = (iPgidxOff==szLeaf);     /* True for first term on page */
+      int nByte;                            /* Bytes of data */
+      int iEnd;
+
+      iPgidxOff += fts5GetVarint32(&a[iPgidxOff], nByte);
+      iPgidxPrev += nByte;
+      iOff = iPgidxPrev;
+
+      if( iPgidxOff<n ){
+        fts5GetVarint32(&a[iPgidxOff], nByte);
+        iEnd = iPgidxPrev + nByte;
+      }else{
+        iEnd = szLeaf;
+      }
+      if( iEnd>szLeaf ){
+        rc = FTS5_CORRUPT;
+        break;
+      }
+
+      if( bFirst==0 ){
+        iOff += fts5GetVarint32(&a[iOff], nByte);
+        if( nByte>term.n ){
+          rc = FTS5_CORRUPT;
+          break;
+        }
+        term.n = nByte;
+      }
+      iOff += fts5GetVarint32(&a[iOff], nByte);
+      if( iOff+nByte>n ){
+        rc = FTS5_CORRUPT;
+        break;
+      }
+      fts5BufferAppendBlob(&rc, &term, nByte, &a[iOff]);
+      iOff += nByte;
+
+      sqlite3Fts5BufferAppendPrintf(&rc, &s, " term=");
+      fts5BufferAppendTerm(&rc, &s, &term);
+      iOff += fts5DecodeDoclist(&rc, &s, &a[iOff], iEnd-iOff);
+    }
+
+    fts5BufferFree(&term);
+  }
+
+ decode_out:
+  sqlite3_free(a);
+  if( rc==SQLITE_OK ){
+    sqlite3_result_text(pCtx, (const char*)s.p, s.n, SQLITE_TRANSIENT);
+  }else{
+    sqlite3_result_error_code(pCtx, rc);
+  }
+  fts5BufferFree(&s);
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+/*
+** The implementation of user-defined scalar function fts5_rowid().
+*/
+static void fts5RowidFunction(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args (always 2) */
+  sqlite3_value **apVal           /* Function arguments */
+){
+  const char *zArg;
+  if( nArg==0 ){
+    sqlite3_result_error(pCtx, "should be: fts5_rowid(subject, ....)", -1);
+  }else{
+    zArg = (const char*)sqlite3_value_text(apVal[0]);
+    if( 0==sqlite3_stricmp(zArg, "segment") ){
+      i64 iRowid;
+      int segid, pgno;
+      if( nArg!=3 ){
+        sqlite3_result_error(pCtx,
+            "should be: fts5_rowid('segment', segid, pgno))", -1
+        );
+      }else{
+        segid = sqlite3_value_int(apVal[1]);
+        pgno = sqlite3_value_int(apVal[2]);
+        iRowid = FTS5_SEGMENT_ROWID(segid, pgno);
+        sqlite3_result_int64(pCtx, iRowid);
+      }
+    }else{
+      sqlite3_result_error(pCtx,
+        "first arg to fts5_rowid() must be 'segment'" , -1
+      );
+    }
+  }
+}
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+
+typedef struct Fts5StructVtab Fts5StructVtab;
+struct Fts5StructVtab {
+  sqlite3_vtab base;
+};
+
+typedef struct Fts5StructVcsr Fts5StructVcsr;
+struct Fts5StructVcsr {
+  sqlite3_vtab_cursor base;
+  Fts5Structure *pStruct;
+  int iLevel;
+  int iSeg;
+  int iRowid;
+};
+
+/*
+** Create a new fts5_structure() table-valued function.
+*/
+static int fts5structConnectMethod(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  Fts5StructVtab *pNew = 0;
+  int rc = SQLITE_OK;
+
+  rc = sqlite3_declare_vtab(db,
+      "CREATE TABLE xyz("
+          "level, segment, merge, segid, leaf1, leaf2, loc1, loc2, "
+          "npgtombstone, nentrytombstone, nentry, struct HIDDEN);"
+  );
+  if( rc==SQLITE_OK ){
+    pNew = sqlite3Fts5MallocZero(&rc, sizeof(*pNew));
+  }
+
+  *ppVtab = (sqlite3_vtab*)pNew;
+  return rc;
+}
+
+/*
+** We must have a single struct=? constraint that will be passed through
+** into the xFilter method.  If there is no valid struct=? constraint,
+** then return an SQLITE_CONSTRAINT error.
+*/
+static int fts5structBestIndexMethod(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  int i;
+  int rc = SQLITE_CONSTRAINT;
+  struct sqlite3_index_constraint *p;
+  pIdxInfo->estimatedCost = (double)100;
+  pIdxInfo->estimatedRows = 100;
+  pIdxInfo->idxNum = 0;
+  for(i=0, p=pIdxInfo->aConstraint; i<pIdxInfo->nConstraint; i++, p++){
+    if( p->usable==0 ) continue;
+    if( p->op==SQLITE_INDEX_CONSTRAINT_EQ && p->iColumn==11 ){
+      rc = SQLITE_OK;
+      pIdxInfo->aConstraintUsage[i].omit = 1;
+      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
+      break;
+    }
+  }
+  return rc;
+}
+
+/*
+** This method is the destructor for bytecodevtab objects.
+*/
+static int fts5structDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts5StructVtab *p = (Fts5StructVtab*)pVtab;
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Constructor for a new bytecodevtab_cursor object.
+*/
+static int fts5structOpenMethod(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCsr){
+  int rc = SQLITE_OK;
+  Fts5StructVcsr *pNew = 0;
+
+  pNew = sqlite3Fts5MallocZero(&rc, sizeof(*pNew));
+  *ppCsr = (sqlite3_vtab_cursor*)pNew;
+
+  return SQLITE_OK;
+}
+
+/*
+** Destructor for a bytecodevtab_cursor.
+*/
+static int fts5structCloseMethod(sqlite3_vtab_cursor *cur){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  fts5StructureRelease(pCsr->pStruct);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+
+/*
+** Advance a bytecodevtab_cursor to its next row of output.
+*/
+static int fts5structNextMethod(sqlite3_vtab_cursor *cur){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  Fts5Structure *p = pCsr->pStruct;
+
+  assert( pCsr->pStruct );
+  pCsr->iSeg++;
+  pCsr->iRowid++;
+  while( pCsr->iLevel<p->nLevel && pCsr->iSeg>=p->aLevel[pCsr->iLevel].nSeg ){
+    pCsr->iLevel++;
+    pCsr->iSeg = 0;
+  }
+  if( pCsr->iLevel>=p->nLevel ){
+    fts5StructureRelease(pCsr->pStruct);
+    pCsr->pStruct = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the cursor has been moved off of the last
+** row of output.
+*/
+static int fts5structEofMethod(sqlite3_vtab_cursor *cur){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  return pCsr->pStruct==0;
+}
+
+static int fts5structRowidMethod(
+  sqlite3_vtab_cursor *cur,
+  sqlite_int64 *piRowid
+){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  *piRowid = pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Return values of columns for the row at which the bytecodevtab_cursor
+** is currently pointing.
+*/
+static int fts5structColumnMethod(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int i                       /* Which column to return */
+){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
+  Fts5Structure *p = pCsr->pStruct;
+  Fts5StructureSegment *pSeg = &p->aLevel[pCsr->iLevel].aSeg[pCsr->iSeg];
+
+  switch( i ){
+    case 0: /* level */
+      sqlite3_result_int(ctx, pCsr->iLevel);
+      break;
+    case 1: /* segment */
+      sqlite3_result_int(ctx, pCsr->iSeg);
+      break;
+    case 2: /* merge */
+      sqlite3_result_int(ctx, pCsr->iSeg < p->aLevel[pCsr->iLevel].nMerge);
+      break;
+    case 3: /* segid */
+      sqlite3_result_int(ctx, pSeg->iSegid);
+      break;
+    case 4: /* leaf1 */
+      sqlite3_result_int(ctx, pSeg->pgnoFirst);
+      break;
+    case 5: /* leaf2 */
+      sqlite3_result_int(ctx, pSeg->pgnoLast);
+      break;
+    case 6: /* origin1 */
+      sqlite3_result_int64(ctx, pSeg->iOrigin1);
+      break;
+    case 7: /* origin2 */
+      sqlite3_result_int64(ctx, pSeg->iOrigin2);
+      break;
+    case 8: /* npgtombstone */
+      sqlite3_result_int(ctx, pSeg->nPgTombstone);
+      break;
+    case 9: /* nentrytombstone */
+      sqlite3_result_int64(ctx, pSeg->nEntryTombstone);
+      break;
+    case 10: /* nentry */
+      sqlite3_result_int64(ctx, pSeg->nEntry);
+      break;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Initialize a cursor.
+**
+**    idxNum==0     means show all subprograms
+**    idxNum==1     means show only the main bytecode and omit subprograms.
+*/
+static int fts5structFilterMethod(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  Fts5StructVcsr *pCsr = (Fts5StructVcsr *)pVtabCursor;
+  int rc = SQLITE_OK;
+
+  const u8 *aBlob = 0;
+  int nBlob = 0;
+
+  assert( argc==1 );
+  fts5StructureRelease(pCsr->pStruct);
+  pCsr->pStruct = 0;
+
+  nBlob = sqlite3_value_bytes(argv[0]);
+  aBlob = (const u8*)sqlite3_value_blob(argv[0]);
+  rc = fts5StructureDecode(aBlob, nBlob, 0, &pCsr->pStruct);
+  if( rc==SQLITE_OK ){
+    pCsr->iLevel = 0;
+    pCsr->iRowid = 0;
+    pCsr->iSeg = -1;
+    rc = fts5structNextMethod(pVtabCursor);
+  }
+
+  return rc;
+}
+
+#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */
+
+/*
+** This is called as part of registering the FTS5 module with database
+** connection db. It registers several user-defined scalar functions useful
+** with FTS5.
+**
+** If successful, SQLITE_OK is returned. If an error occurs, some other
+** SQLite error code is returned instead.
+*/
+static int sqlite3Fts5IndexInit(sqlite3 *db){
+#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
+  int rc = sqlite3_create_function(
+      db, "fts5_decode", 2, SQLITE_UTF8, 0, fts5DecodeFunction, 0, 0
+  );
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(
+        db, "fts5_decode_none", 2,
+        SQLITE_UTF8, (void*)db, fts5DecodeFunction, 0, 0
+    );
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(
+        db, "fts5_rowid", -1, SQLITE_UTF8, 0, fts5RowidFunction, 0, 0
+    );
+  }
+
+  if( rc==SQLITE_OK ){
+    static const sqlite3_module fts5structure_module = {
+      0,                           /* iVersion      */
+      0,                           /* xCreate       */
+      fts5structConnectMethod,     /* xConnect      */
+      fts5structBestIndexMethod,   /* xBestIndex    */
+      fts5structDisconnectMethod,  /* xDisconnect   */
+      0,                           /* xDestroy      */
+      fts5structOpenMethod,        /* xOpen         */
+      fts5structCloseMethod,       /* xClose        */
+      fts5structFilterMethod,      /* xFilter       */
+      fts5structNextMethod,        /* xNext         */
+      fts5structEofMethod,         /* xEof          */
+      fts5structColumnMethod,      /* xColumn       */
+      fts5structRowidMethod,       /* xRowid        */
+      0,                           /* xUpdate       */
+      0,                           /* xBegin        */
+      0,                           /* xSync         */
+      0,                           /* xCommit       */
+      0,                           /* xRollback     */
+      0,                           /* xFindFunction */
+      0,                           /* xRename       */
+      0,                           /* xSavepoint    */
+      0,                           /* xRelease      */
+      0,                           /* xRollbackTo   */
+      0,                           /* xShadowName   */
+      0                            /* xIntegrity    */
+    };
+    rc = sqlite3_create_module(db, "fts5_structure", &fts5structure_module, 0);
+  }
+  return rc;
+#else
+  return SQLITE_OK;
+  UNUSED_PARAM(db);
+#endif
+}
+
+
+static int sqlite3Fts5IndexReset(Fts5Index *p){
+  assert( p->pStruct==0 || p->iStructVersion!=0 );
+  if( fts5IndexDataVersion(p)!=p->iStructVersion ){
+    fts5StructureInvalidate(p);
+  }
+  return fts5IndexReturn(p);
+}
+
+/*
+** 2014 Jun 09
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is an SQLite module implementing full-text search.
+*/
+
+
+/* #include "fts5Int.h" */
+
+/*
+** This variable is set to false when running tests for which the on disk
+** structures should not be corrupt. Otherwise, true. If it is false, extra
+** assert() conditions in the fts5 code are activated - conditions that are
+** only true if it is guaranteed that the fts5 database is not corrupt.
+*/
+#ifdef SQLITE_DEBUG
+SQLITE_API int sqlite3_fts5_may_be_corrupt = 1;
+#endif
+
+
+typedef struct Fts5Auxdata Fts5Auxdata;
+typedef struct Fts5Auxiliary Fts5Auxiliary;
+typedef struct Fts5Cursor Fts5Cursor;
+typedef struct Fts5FullTable Fts5FullTable;
+typedef struct Fts5Sorter Fts5Sorter;
+typedef struct Fts5TokenizerModule Fts5TokenizerModule;
+
+/*
+** NOTES ON TRANSACTIONS:
+**
+** SQLite invokes the following virtual table methods as transactions are
+** opened and closed by the user:
+**
+**     xBegin():    Start of a new transaction.
+**     xSync():     Initial part of two-phase commit.
+**     xCommit():   Final part of two-phase commit.
+**     xRollback(): Rollback the transaction.
+**
+** Anything that is required as part of a commit that may fail is performed
+** in the xSync() callback. Current versions of SQLite ignore any errors
+** returned by xCommit().
+**
+** And as sub-transactions are opened/closed:
+**
+**     xSavepoint(int S):  Open savepoint S.
+**     xRelease(int S):    Commit and close savepoint S.
+**     xRollbackTo(int S): Rollback to start of savepoint S.
+**
+** During a write-transaction the fts5_index.c module may cache some data
+** in-memory. It is flushed to disk whenever xSync(), xRelease() or
+** xSavepoint() is called. And discarded whenever xRollback() or xRollbackTo()
+** is called.
+**
+** Additionally, if SQLITE_DEBUG is defined, an instance of the following
+** structure is used to record the current transaction state. This information
+** is not required, but it is used in the assert() statements executed by
+** function fts5CheckTransactionState() (see below).
+*/
+struct Fts5TransactionState {
+  int eState;                     /* 0==closed, 1==open, 2==synced */
+  int iSavepoint;                 /* Number of open savepoints (0 -> none) */
+};
+
+/*
+** A single object of this type is allocated when the FTS5 module is
+** registered with a database handle. It is used to store pointers to
+** all registered FTS5 extensions - tokenizers and auxiliary functions.
+*/
+struct Fts5Global {
+  fts5_api api;                   /* User visible part of object (see fts5.h) */
+  sqlite3 *db;                    /* Associated database connection */
+  i64 iNextId;                    /* Used to allocate unique cursor ids */
+  Fts5Auxiliary *pAux;            /* First in list of all aux. functions */
+  Fts5TokenizerModule *pTok;      /* First in list of all tokenizer modules */
+  Fts5TokenizerModule *pDfltTok;  /* Default tokenizer module */
+  Fts5Cursor *pCsr;               /* First in list of all open cursors */
+  u32 aLocaleHdr[4];
+};
+
+/*
+** Size of header on fts5_locale() values. And macro to access a buffer
+** containing a copy of the header from an Fts5Config pointer.
+*/
+#define FTS5_LOCALE_HDR_SIZE ((int)sizeof( ((Fts5Global*)0)->aLocaleHdr ))
+#define FTS5_LOCALE_HDR(pConfig) ((const u8*)(pConfig->pGlobal->aLocaleHdr))
+
+#define FTS5_INSTTOKEN_SUBTYPE 73
+
+/*
+** Each auxiliary function registered with the FTS5 module is represented
+** by an object of the following type. All such objects are stored as part
+** of the Fts5Global.pAux list.
+*/
+struct Fts5Auxiliary {
+  Fts5Global *pGlobal;            /* Global context for this function */
+  char *zFunc;                    /* Function name (nul-terminated) */
+  void *pUserData;                /* User-data pointer */
+  fts5_extension_function xFunc;  /* Callback function */
+  void (*xDestroy)(void*);        /* Destructor function */
+  Fts5Auxiliary *pNext;           /* Next registered auxiliary function */
+};
+
+/*
+** Each tokenizer module registered with the FTS5 module is represented
+** by an object of the following type. All such objects are stored as part
+** of the Fts5Global.pTok list.
+**
+** bV2Native:
+**  True if the tokenizer was registered using xCreateTokenizer_v2(), false
+**  for xCreateTokenizer(). If this variable is true, then x2 is populated
+**  with the routines as supplied by the caller and x1 contains synthesized
+**  wrapper routines. In this case the user-data pointer passed to
+**  x1.xCreate should be a pointer to the Fts5TokenizerModule structure,
+**  not a copy of pUserData.
+**
+**  Of course, if bV2Native is false, then x1 contains the real routines and
+**  x2 the synthesized ones. In this case a pointer to the Fts5TokenizerModule
+**  object should be passed to x2.xCreate.
+**
+**  The synthesized wrapper routines are necessary for xFindTokenizer(_v2)
+**  calls.
+*/
+struct Fts5TokenizerModule {
+  char *zName;                    /* Name of tokenizer */
+  void *pUserData;                /* User pointer passed to xCreate() */
+  int bV2Native;                  /* True if v2 native tokenizer */
+  fts5_tokenizer x1;              /* Tokenizer functions */
+  fts5_tokenizer_v2 x2;           /* V2 tokenizer functions */
+  void (*xDestroy)(void*);        /* Destructor function */
+  Fts5TokenizerModule *pNext;     /* Next registered tokenizer module */
+};
+
+struct Fts5FullTable {
+  Fts5Table p;                    /* Public class members from fts5Int.h */
+  Fts5Storage *pStorage;          /* Document store */
+  Fts5Global *pGlobal;            /* Global (connection wide) data */
+  Fts5Cursor *pSortCsr;           /* Sort data from this cursor */
+  int iSavepoint;                 /* Successful xSavepoint()+1 */
+
+#ifdef SQLITE_DEBUG
+  struct Fts5TransactionState ts;
+#endif
+};
+
+struct Fts5MatchPhrase {
+  Fts5Buffer *pPoslist;           /* Pointer to current poslist */
+  int nTerm;                      /* Size of phrase in terms */
+};
+
+/*
+** pStmt:
+**   SELECT rowid, <fts> FROM <fts> ORDER BY +rank;
+**
+** aIdx[]:
+**   There is one entry in the aIdx[] array for each phrase in the query,
+**   the value of which is the offset within aPoslist[] following the last
+**   byte of the position list for the corresponding phrase.
+*/
+struct Fts5Sorter {
+  sqlite3_stmt *pStmt;
+  i64 iRowid;                     /* Current rowid */
+  const u8 *aPoslist;             /* Position lists for current row */
+  int nIdx;                       /* Number of entries in aIdx[] */
+  int aIdx[1];                    /* Offsets into aPoslist for current row */
+};
+
+
+/*
+** Virtual-table cursor object.
+**
+** iSpecial:
+**   If this is a 'special' query (refer to function fts5SpecialMatch()),
+**   then this variable contains the result of the query.
+**
+** iFirstRowid, iLastRowid:
+**   These variables are only used for FTS5_PLAN_MATCH cursors. Assuming the
+**   cursor iterates in ascending order of rowids, iFirstRowid is the lower
+**   limit of rowids to return, and iLastRowid the upper. In other words, the
+**   WHERE clause in the user's query might have been:
+**
+**       <tbl> MATCH <expr> AND rowid BETWEEN $iFirstRowid AND $iLastRowid
+**
+**   If the cursor iterates in descending order of rowid, iFirstRowid
+**   is the upper limit (i.e. the "first" rowid visited) and iLastRowid
+**   the lower.
+*/
+struct Fts5Cursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  Fts5Cursor *pNext;              /* Next cursor in Fts5Cursor.pCsr list */
+  int *aColumnSize;               /* Values for xColumnSize() */
+  i64 iCsrId;                     /* Cursor id */
+
+  /* Zero from this point onwards on cursor reset */
+  int ePlan;                      /* FTS5_PLAN_XXX value */
+  int bDesc;                      /* True for "ORDER BY rowid DESC" queries */
+  i64 iFirstRowid;                /* Return no rowids earlier than this */
+  i64 iLastRowid;                 /* Return no rowids later than this */
+  sqlite3_stmt *pStmt;            /* Statement used to read %_content */
+  Fts5Expr *pExpr;                /* Expression for MATCH queries */
+  Fts5Sorter *pSorter;            /* Sorter for "ORDER BY rank" queries */
+  int csrflags;                   /* Mask of cursor flags (see below) */
+  i64 iSpecial;                   /* Result of special query */
+
+  /* "rank" function. Populated on demand from vtab.xColumn(). */
+  char *zRank;                    /* Custom rank function */
+  char *zRankArgs;                /* Custom rank function args */
+  Fts5Auxiliary *pRank;           /* Rank callback (or NULL) */
+  int nRankArg;                   /* Number of trailing arguments for rank() */
+  sqlite3_value **apRankArg;      /* Array of trailing arguments */
+  sqlite3_stmt *pRankArgStmt;     /* Origin of objects in apRankArg[] */
+
+  /* Auxiliary data storage */
+  Fts5Auxiliary *pAux;            /* Currently executing extension function */
+  Fts5Auxdata *pAuxdata;          /* First in linked list of saved aux-data */
+
+  /* Cache used by auxiliary API functions xInst() and xInstCount() */
+  Fts5PoslistReader *aInstIter;   /* One for each phrase */
+  int nInstAlloc;                 /* Size of aInst[] array (entries / 3) */
+  int nInstCount;                 /* Number of phrase instances */
+  int *aInst;                     /* 3 integers per phrase instance */
+};
+
+/*
+** Bits that make up the "idxNum" parameter passed indirectly by
+** xBestIndex() to xFilter().
+*/
+#define FTS5_BI_MATCH        0x0001         /* <tbl> MATCH ? */
+#define FTS5_BI_RANK         0x0002         /* rank MATCH ? */
+#define FTS5_BI_ROWID_EQ     0x0004         /* rowid == ? */
+#define FTS5_BI_ROWID_LE     0x0008         /* rowid <= ? */
+#define FTS5_BI_ROWID_GE     0x0010         /* rowid >= ? */
+
+#define FTS5_BI_ORDER_RANK   0x0020
+#define FTS5_BI_ORDER_ROWID  0x0040
+#define FTS5_BI_ORDER_DESC   0x0080
+
+/*
+** Values for Fts5Cursor.csrflags
+*/
+#define FTS5CSR_EOF               0x01
+#define FTS5CSR_REQUIRE_CONTENT   0x02
+#define FTS5CSR_REQUIRE_DOCSIZE   0x04
+#define FTS5CSR_REQUIRE_INST      0x08
+#define FTS5CSR_FREE_ZRANK        0x10
+#define FTS5CSR_REQUIRE_RESEEK    0x20
+#define FTS5CSR_REQUIRE_POSLIST   0x40
+
+#define BitFlagAllTest(x,y) (((x) & (y))==(y))
+#define BitFlagTest(x,y)    (((x) & (y))!=0)
+
+
+/*
+** Macros to Set(), Clear() and Test() cursor flags.
+*/
+#define CsrFlagSet(pCsr, flag)   ((pCsr)->csrflags |= (flag))
+#define CsrFlagClear(pCsr, flag) ((pCsr)->csrflags &= ~(flag))
+#define CsrFlagTest(pCsr, flag)  ((pCsr)->csrflags & (flag))
+
+struct Fts5Auxdata {
+  Fts5Auxiliary *pAux;            /* Extension to which this belongs */
+  void *pPtr;                     /* Pointer value */
+  void(*xDelete)(void*);          /* Destructor */
+  Fts5Auxdata *pNext;             /* Next object in linked list */
+};
+
+#ifdef SQLITE_DEBUG
+#define FTS5_BEGIN      1
+#define FTS5_SYNC       2
+#define FTS5_COMMIT     3
+#define FTS5_ROLLBACK   4
+#define FTS5_SAVEPOINT  5
+#define FTS5_RELEASE    6
+#define FTS5_ROLLBACKTO 7
+static void fts5CheckTransactionState(Fts5FullTable *p, int op, int iSavepoint){
+  switch( op ){
+    case FTS5_BEGIN:
+      assert( p->ts.eState==0 );
+      p->ts.eState = 1;
+      p->ts.iSavepoint = -1;
+      break;
+
+    case FTS5_SYNC:
+      assert( p->ts.eState==1 || p->ts.eState==2 );
+      p->ts.eState = 2;
+      break;
+
+    case FTS5_COMMIT:
+      assert( p->ts.eState==2 );
+      p->ts.eState = 0;
+      break;
+
+    case FTS5_ROLLBACK:
+      assert( p->ts.eState==1 || p->ts.eState==2 || p->ts.eState==0 );
+      p->ts.eState = 0;
+      break;
+
+    case FTS5_SAVEPOINT:
+      assert( p->ts.eState>=1 );
+      assert( iSavepoint>=0 );
+      assert( iSavepoint>=p->ts.iSavepoint );
+      p->ts.iSavepoint = iSavepoint;
+      break;
+
+    case FTS5_RELEASE:
+      assert( p->ts.eState>=1 );
+      assert( iSavepoint>=0 );
+      assert( iSavepoint<=p->ts.iSavepoint );
+      p->ts.iSavepoint = iSavepoint-1;
+      break;
+
+    case FTS5_ROLLBACKTO:
+      assert( p->ts.eState>=1 );
+      assert( iSavepoint>=-1 );
+      /* The following assert() can fail if another vtab strikes an error
+      ** within an xSavepoint() call then SQLite calls xRollbackTo() - without
+      ** having called xSavepoint() on this vtab.  */
+      /* assert( iSavepoint<=p->ts.iSavepoint ); */
+      p->ts.iSavepoint = iSavepoint;
+      break;
+  }
+}
+#else
+# define fts5CheckTransactionState(x,y,z)
+#endif
+
+/*
+** Return true if pTab is a contentless table. If parameter bIncludeUnindexed
+** is true, this includes contentless tables that store UNINDEXED columns
+** only.
+*/
+static int fts5IsContentless(Fts5FullTable *pTab, int bIncludeUnindexed){
+  int eContent = pTab->p.pConfig->eContent;
+  return (
+    eContent==FTS5_CONTENT_NONE
+    || (bIncludeUnindexed && eContent==FTS5_CONTENT_UNINDEXED)
+  );
+}
+
+/*
+** Delete a virtual table handle allocated by fts5InitVtab().
+*/
+static void fts5FreeVtab(Fts5FullTable *pTab){
+  if( pTab ){
+    sqlite3Fts5IndexClose(pTab->p.pIndex);
+    sqlite3Fts5StorageClose(pTab->pStorage);
+    sqlite3Fts5ConfigFree(pTab->p.pConfig);
+    sqlite3_free(pTab);
+  }
+}
+
+/*
+** The xDisconnect() virtual table method.
+*/
+static int fts5DisconnectMethod(sqlite3_vtab *pVtab){
+  fts5FreeVtab((Fts5FullTable*)pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** The xDestroy() virtual table method.
+*/
+static int fts5DestroyMethod(sqlite3_vtab *pVtab){
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  int rc = sqlite3Fts5DropAll(pTab->pConfig);
+  if( rc==SQLITE_OK ){
+    fts5FreeVtab((Fts5FullTable*)pVtab);
+  }
+  return rc;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the FTS3 virtual table.
+**
+** The argv[] array contains the following:
+**
+**   argv[0]   -> module name  ("fts5")
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> "column name" and other module argument fields.
+*/
+static int fts5InitVtab(
+  int bCreate,                    /* True for xCreate, false for xConnect */
+  sqlite3 *db,                    /* The SQLite database connection */
+  void *pAux,                     /* Hash table containing tokenizers */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
+  char **pzErr                    /* Write any error message here */
+){
+  Fts5Global *pGlobal = (Fts5Global*)pAux;
+  const char **azConfig = (const char**)argv;
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5Config *pConfig = 0;        /* Results of parsing argc/argv */
+  Fts5FullTable *pTab = 0;        /* New virtual table object */
+
+  /* Allocate the new vtab object and parse the configuration */
+  pTab = (Fts5FullTable*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5FullTable));
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ConfigParse(pGlobal, db, argc, azConfig, &pConfig, pzErr);
+    assert( (rc==SQLITE_OK && *pzErr==0) || pConfig==0 );
+  }
+  if( rc==SQLITE_OK ){
+    pConfig->pzErrmsg = pzErr;
+    pTab->p.pConfig = pConfig;
+    pTab->pGlobal = pGlobal;
+    if( bCreate || sqlite3Fts5TokenizerPreload(&pConfig->t) ){
+      rc = sqlite3Fts5LoadTokenizer(pConfig);
+    }
+  }
+
+  /* Open the index sub-system */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexOpen(pConfig, bCreate, &pTab->p.pIndex, pzErr);
+  }
+
+  /* Open the storage sub-system */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageOpen(
+        pConfig, pTab->p.pIndex, bCreate, &pTab->pStorage, pzErr
+    );
+  }
+
+  /* Call sqlite3_declare_vtab() */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ConfigDeclareVtab(pConfig);
+  }
+
+  /* Load the initial configuration */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ConfigLoad(pTab->p.pConfig, pTab->p.pConfig->iCookie-1);
+  }
+
+  if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_NORMAL ){
+    rc = sqlite3_vtab_config(db, SQLITE_VTAB_CONSTRAINT_SUPPORT, (int)1);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
+  }
+
+  if( pConfig ) pConfig->pzErrmsg = 0;
+  if( rc!=SQLITE_OK ){
+    fts5FreeVtab(pTab);
+    pTab = 0;
+  }else if( bCreate ){
+    fts5CheckTransactionState(pTab, FTS5_BEGIN, 0);
+  }
+  *ppVTab = (sqlite3_vtab*)pTab;
+  return rc;
+}
+
+/*
+** The xConnect() and xCreate() methods for the virtual table. All the
+** work is done in function fts5InitVtab().
+*/
+static int fts5ConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr);
+}
+static int fts5CreateMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr);
+}
+
+/*
+** The different query plans.
+*/
+#define FTS5_PLAN_MATCH          1       /* (<tbl> MATCH ?) */
+#define FTS5_PLAN_SOURCE         2       /* A source cursor for SORTED_MATCH */
+#define FTS5_PLAN_SPECIAL        3       /* An internal query */
+#define FTS5_PLAN_SORTED_MATCH   4       /* (<tbl> MATCH ? ORDER BY rank) */
+#define FTS5_PLAN_SCAN           5       /* No usable constraint */
+#define FTS5_PLAN_ROWID          6       /* (rowid = ?) */
+
+/*
+** Set the SQLITE_INDEX_SCAN_UNIQUE flag in pIdxInfo->flags. Unless this
+** extension is currently being used by a version of SQLite too old to
+** support index-info flags. In that case this function is a no-op.
+*/
+static void fts5SetUniqueFlag(sqlite3_index_info *pIdxInfo){
+#if SQLITE_VERSION_NUMBER>=3008012
+#ifndef SQLITE_CORE
+  if( sqlite3_libversion_number()>=3008012 )
+#endif
+  {
+    pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_UNIQUE;
+  }
+#endif
+}
+
+static int fts5UsePatternMatch(
+  Fts5Config *pConfig,
+  struct sqlite3_index_constraint *p
+){
+  assert( FTS5_PATTERN_GLOB==SQLITE_INDEX_CONSTRAINT_GLOB );
+  assert( FTS5_PATTERN_LIKE==SQLITE_INDEX_CONSTRAINT_LIKE );
+  if( pConfig->t.ePattern==FTS5_PATTERN_GLOB && p->op==FTS5_PATTERN_GLOB ){
+    return 1;
+  }
+  if( pConfig->t.ePattern==FTS5_PATTERN_LIKE
+   && (p->op==FTS5_PATTERN_LIKE || p->op==FTS5_PATTERN_GLOB)
+  ){
+    return 1;
+  }
+  return 0;
+}
+
+/*
+** Implementation of the xBestIndex method for FTS5 tables. Within the
+** WHERE constraint, it searches for the following:
+**
+**   1. A MATCH constraint against the table column.
+**   2. A MATCH constraint against the "rank" column.
+**   3. A MATCH constraint against some other column.
+**   4. An == constraint against the rowid column.
+**   5. A < or <= constraint against the rowid column.
+**   6. A > or >= constraint against the rowid column.
+**
+** Within the ORDER BY, the following are supported:
+**
+**   5. ORDER BY rank [ASC|DESC]
+**   6. ORDER BY rowid [ASC|DESC]
+**
+** Information for the xFilter call is passed via both the idxNum and
+** idxStr variables. Specifically, idxNum is a bitmask of the following
+** flags used to encode the ORDER BY clause:
+**
+**     FTS5_BI_ORDER_RANK
+**     FTS5_BI_ORDER_ROWID
+**     FTS5_BI_ORDER_DESC
+**
+** idxStr is used to encode data from the WHERE clause. For each argument
+** passed to the xFilter method, the following is appended to idxStr:
+**
+**   Match against table column:            "m"
+**   Match against rank column:             "r"
+**   Match against other column:            "M<column-number>"
+**   LIKE  against other column:            "L<column-number>"
+**   GLOB  against other column:            "G<column-number>"
+**   Equality constraint against the rowid: "="
+**   A < or <= against the rowid:           "<"
+**   A > or >= against the rowid:           ">"
+**
+** This function ensures that there is at most one "r" or "=". And that if
+** there exists an "=" then there is no "<" or ">".
+**
+** If an unusable MATCH operator is present in the WHERE clause, then
+** SQLITE_CONSTRAINT is returned.
+**
+** Costs are assigned as follows:
+**
+**  a) If a MATCH operator is present, the cost depends on the other
+**     constraints also present. As follows:
+**
+**       * No other constraints:         cost=1000.0
+**       * One rowid range constraint:   cost=750.0
+**       * Both rowid range constraints: cost=500.0
+**       * An == rowid constraint:       cost=100.0
+**
+**  b) Otherwise, if there is no MATCH:
+**
+**       * No other constraints:         cost=1000000.0
+**       * One rowid range constraint:   cost=750000.0
+**       * Both rowid range constraints: cost=250000.0
+**       * An == rowid constraint:       cost=10.0
+**
+** Costs are not modified by the ORDER BY clause.
+*/
+static int fts5BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
+  Fts5Table *pTab = (Fts5Table*)pVTab;
+  Fts5Config *pConfig = pTab->pConfig;
+  const int nCol = pConfig->nCol;
+  int idxFlags = 0;               /* Parameter passed through to xFilter() */
+  int i;
+
+  char *idxStr;
+  int iIdxStr = 0;
+  int iCons = 0;
+
+  int bSeenEq = 0;
+  int bSeenGt = 0;
+  int bSeenLt = 0;
+  int nSeenMatch = 0;
+  int bSeenRank = 0;
+
+
+  assert( SQLITE_INDEX_CONSTRAINT_EQ<SQLITE_INDEX_CONSTRAINT_MATCH );
+  assert( SQLITE_INDEX_CONSTRAINT_GT<SQLITE_INDEX_CONSTRAINT_MATCH );
+  assert( SQLITE_INDEX_CONSTRAINT_LE<SQLITE_INDEX_CONSTRAINT_MATCH );
+  assert( SQLITE_INDEX_CONSTRAINT_GE<SQLITE_INDEX_CONSTRAINT_MATCH );
+  assert( SQLITE_INDEX_CONSTRAINT_LE<SQLITE_INDEX_CONSTRAINT_MATCH );
+
+  if( pConfig->bLock ){
+    pTab->base.zErrMsg = sqlite3_mprintf(
+        "recursively defined fts5 content table"
+    );
+    return SQLITE_ERROR;
+  }
+
+  idxStr = (char*)sqlite3_malloc(pInfo->nConstraint * 8 + 1);
+  if( idxStr==0 ) return SQLITE_NOMEM;
+  pInfo->idxStr = idxStr;
+  pInfo->needToFreeIdxStr = 1;
+
+  for(i=0; i<pInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *p = &pInfo->aConstraint[i];
+    int iCol = p->iColumn;
+    if( p->op==SQLITE_INDEX_CONSTRAINT_MATCH
+     || (p->op==SQLITE_INDEX_CONSTRAINT_EQ && iCol>=nCol)
+    ){
+      /* A MATCH operator or equivalent */
+      if( p->usable==0 || iCol<0 ){
+        /* As there exists an unusable MATCH constraint this is an
+        ** unusable plan. Return SQLITE_CONSTRAINT. */
+        idxStr[iIdxStr] = 0;
+        return SQLITE_CONSTRAINT;
+      }else{
+        if( iCol==nCol+1 ){
+          if( bSeenRank ) continue;
+          idxStr[iIdxStr++] = 'r';
+          bSeenRank = 1;
+        }else{
+          nSeenMatch++;
+          idxStr[iIdxStr++] = 'M';
+          sqlite3_snprintf(6, &idxStr[iIdxStr], "%d", iCol);
+          idxStr += strlen(&idxStr[iIdxStr]);
+          assert( idxStr[iIdxStr]=='\0' );
+        }
+        pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+        pInfo->aConstraintUsage[i].omit = 1;
+      }
+    }else if( p->usable ){
+      if( iCol>=0 && iCol<nCol && fts5UsePatternMatch(pConfig, p) ){
+        assert( p->op==FTS5_PATTERN_LIKE || p->op==FTS5_PATTERN_GLOB );
+        idxStr[iIdxStr++] = p->op==FTS5_PATTERN_LIKE ? 'L' : 'G';
+        sqlite3_snprintf(6, &idxStr[iIdxStr], "%d", iCol);
+        idxStr += strlen(&idxStr[iIdxStr]);
+        pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+        assert( idxStr[iIdxStr]=='\0' );
+        nSeenMatch++;
+      }else if( bSeenEq==0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ && iCol<0 ){
+        idxStr[iIdxStr++] = '=';
+        bSeenEq = 1;
+        pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+      }
+    }
+  }
+
+  if( bSeenEq==0 ){
+    for(i=0; i<pInfo->nConstraint; i++){
+      struct sqlite3_index_constraint *p = &pInfo->aConstraint[i];
+      if( p->iColumn<0 && p->usable ){
+        int op = p->op;
+        if( op==SQLITE_INDEX_CONSTRAINT_LT || op==SQLITE_INDEX_CONSTRAINT_LE ){
+          if( bSeenLt ) continue;
+          idxStr[iIdxStr++] = '<';
+          pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+          bSeenLt = 1;
+        }else
+        if( op==SQLITE_INDEX_CONSTRAINT_GT || op==SQLITE_INDEX_CONSTRAINT_GE ){
+          if( bSeenGt ) continue;
+          idxStr[iIdxStr++] = '>';
+          pInfo->aConstraintUsage[i].argvIndex = ++iCons;
+          bSeenGt = 1;
+        }
+      }
+    }
+  }
+  idxStr[iIdxStr] = '\0';
+
+  /* Set idxFlags flags for the ORDER BY clause
+  **
+  ** Note that tokendata=1 tables cannot currently handle "ORDER BY rowid DESC".
+  */
+  if( pInfo->nOrderBy==1 ){
+    int iSort = pInfo->aOrderBy[0].iColumn;
+    if( iSort==(pConfig->nCol+1) && nSeenMatch>0 ){
+      idxFlags |= FTS5_BI_ORDER_RANK;
+    }else if( iSort==-1 && (!pInfo->aOrderBy[0].desc || !pConfig->bTokendata) ){
+      idxFlags |= FTS5_BI_ORDER_ROWID;
+    }
+    if( BitFlagTest(idxFlags, FTS5_BI_ORDER_RANK|FTS5_BI_ORDER_ROWID) ){
+      pInfo->orderByConsumed = 1;
+      if( pInfo->aOrderBy[0].desc ){
+        idxFlags |= FTS5_BI_ORDER_DESC;
+      }
+    }
+  }
+
+  /* Calculate the estimated cost based on the flags set in idxFlags. */
+  if( bSeenEq ){
+    pInfo->estimatedCost = nSeenMatch ? 1000.0 : 10.0;
+    if( nSeenMatch==0 ) fts5SetUniqueFlag(pInfo);
+  }else if( bSeenLt && bSeenGt ){
+    pInfo->estimatedCost = nSeenMatch ? 5000.0 : 250000.0;
+  }else if( bSeenLt || bSeenGt ){
+    pInfo->estimatedCost = nSeenMatch ? 7500.0 : 750000.0;
+  }else{
+    pInfo->estimatedCost = nSeenMatch ? 10000.0 : 1000000.0;
+  }
+  for(i=1; i<nSeenMatch; i++){
+    pInfo->estimatedCost *= 0.4;
+  }
+
+  pInfo->idxNum = idxFlags;
+  return SQLITE_OK;
+}
+
+static int fts5NewTransaction(Fts5FullTable *pTab){
+  Fts5Cursor *pCsr;
+  for(pCsr=pTab->pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
+    if( pCsr->base.pVtab==(sqlite3_vtab*)pTab ) return SQLITE_OK;
+  }
+  return sqlite3Fts5StorageReset(pTab->pStorage);
+}
+
+/*
+** Implementation of xOpen method.
+*/
+static int fts5OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVTab;
+  Fts5Config *pConfig = pTab->p.pConfig;
+  Fts5Cursor *pCsr = 0;           /* New cursor object */
+  sqlite3_int64 nByte;            /* Bytes of space to allocate */
+  int rc;                         /* Return code */
+
+  rc = fts5NewTransaction(pTab);
+  if( rc==SQLITE_OK ){
+    nByte = sizeof(Fts5Cursor) + pConfig->nCol * sizeof(int);
+    pCsr = (Fts5Cursor*)sqlite3_malloc64(nByte);
+    if( pCsr ){
+      Fts5Global *pGlobal = pTab->pGlobal;
+      memset(pCsr, 0, (size_t)nByte);
+      pCsr->aColumnSize = (int*)&pCsr[1];
+      pCsr->pNext = pGlobal->pCsr;
+      pGlobal->pCsr = pCsr;
+      pCsr->iCsrId = ++pGlobal->iNextId;
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
+  return rc;
+}
+
+static int fts5StmtType(Fts5Cursor *pCsr){
+  if( pCsr->ePlan==FTS5_PLAN_SCAN ){
+    return (pCsr->bDesc) ? FTS5_STMT_SCAN_DESC : FTS5_STMT_SCAN_ASC;
+  }
+  return FTS5_STMT_LOOKUP;
+}
+
+/*
+** This function is called after the cursor passed as the only argument
+** is moved to point at a different row. It clears all cached data
+** specific to the previous row stored by the cursor object.
+*/
+static void fts5CsrNewrow(Fts5Cursor *pCsr){
+  CsrFlagSet(pCsr,
+      FTS5CSR_REQUIRE_CONTENT
+    | FTS5CSR_REQUIRE_DOCSIZE
+    | FTS5CSR_REQUIRE_INST
+    | FTS5CSR_REQUIRE_POSLIST
+  );
+}
+
+static void fts5FreeCursorComponents(Fts5Cursor *pCsr){
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  Fts5Auxdata *pData;
+  Fts5Auxdata *pNext;
+
+  sqlite3_free(pCsr->aInstIter);
+  sqlite3_free(pCsr->aInst);
+  if( pCsr->pStmt ){
+    int eStmt = fts5StmtType(pCsr);
+    sqlite3Fts5StorageStmtRelease(pTab->pStorage, eStmt, pCsr->pStmt);
+  }
+  if( pCsr->pSorter ){
+    Fts5Sorter *pSorter = pCsr->pSorter;
+    sqlite3_finalize(pSorter->pStmt);
+    sqlite3_free(pSorter);
+  }
+
+  if( pCsr->ePlan!=FTS5_PLAN_SOURCE ){
+    sqlite3Fts5ExprFree(pCsr->pExpr);
+  }
+
+  for(pData=pCsr->pAuxdata; pData; pData=pNext){
+    pNext = pData->pNext;
+    if( pData->xDelete ) pData->xDelete(pData->pPtr);
+    sqlite3_free(pData);
+  }
+
+  sqlite3_finalize(pCsr->pRankArgStmt);
+  sqlite3_free(pCsr->apRankArg);
+
+  if( CsrFlagTest(pCsr, FTS5CSR_FREE_ZRANK) ){
+    sqlite3_free(pCsr->zRank);
+    sqlite3_free(pCsr->zRankArgs);
+  }
+
+  sqlite3Fts5IndexCloseReader(pTab->p.pIndex);
+  memset(&pCsr->ePlan, 0, sizeof(Fts5Cursor) - ((u8*)&pCsr->ePlan - (u8*)pCsr));
+}
+
+
+/*
+** Close the cursor.  For additional information see the documentation
+** on the xClose method of the virtual table interface.
+*/
+static int fts5CloseMethod(sqlite3_vtab_cursor *pCursor){
+  if( pCursor ){
+    Fts5FullTable *pTab = (Fts5FullTable*)(pCursor->pVtab);
+    Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+    Fts5Cursor **pp;
+
+    fts5FreeCursorComponents(pCsr);
+    /* Remove the cursor from the Fts5Global.pCsr list */
+    for(pp=&pTab->pGlobal->pCsr; (*pp)!=pCsr; pp=&(*pp)->pNext);
+    *pp = pCsr->pNext;
+
+    sqlite3_free(pCsr);
+  }
+  return SQLITE_OK;
+}
+
+static int fts5SorterNext(Fts5Cursor *pCsr){
+  Fts5Sorter *pSorter = pCsr->pSorter;
+  int rc;
+
+  rc = sqlite3_step(pSorter->pStmt);
+  if( rc==SQLITE_DONE ){
+    rc = SQLITE_OK;
+    CsrFlagSet(pCsr, FTS5CSR_EOF|FTS5CSR_REQUIRE_CONTENT);
+  }else if( rc==SQLITE_ROW ){
+    const u8 *a;
+    const u8 *aBlob;
+    int nBlob;
+    int i;
+    int iOff = 0;
+    rc = SQLITE_OK;
+
+    pSorter->iRowid = sqlite3_column_int64(pSorter->pStmt, 0);
+    nBlob = sqlite3_column_bytes(pSorter->pStmt, 1);
+    aBlob = a = sqlite3_column_blob(pSorter->pStmt, 1);
+
+    /* nBlob==0 in detail=none mode. */
+    if( nBlob>0 ){
+      for(i=0; i<(pSorter->nIdx-1); i++){
+        int iVal;
+        a += fts5GetVarint32(a, iVal);
+        iOff += iVal;
+        pSorter->aIdx[i] = iOff;
+      }
+      pSorter->aIdx[i] = &aBlob[nBlob] - a;
+      pSorter->aPoslist = a;
+    }
+
+    fts5CsrNewrow(pCsr);
+  }
+
+  return rc;
+}
+
+
+/*
+** Set the FTS5CSR_REQUIRE_RESEEK flag on all FTS5_PLAN_MATCH cursors
+** open on table pTab.
+*/
+static void fts5TripCursors(Fts5FullTable *pTab){
+  Fts5Cursor *pCsr;
+  for(pCsr=pTab->pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
+    if( pCsr->ePlan==FTS5_PLAN_MATCH
+     && pCsr->base.pVtab==(sqlite3_vtab*)pTab
+    ){
+      CsrFlagSet(pCsr, FTS5CSR_REQUIRE_RESEEK);
+    }
+  }
+}
+
+/*
+** If the REQUIRE_RESEEK flag is set on the cursor passed as the first
+** argument, close and reopen all Fts5IndexIter iterators that the cursor
+** is using. Then attempt to move the cursor to a rowid equal to or laster
+** (in the cursors sort order - ASC or DESC) than the current rowid.
+**
+** If the new rowid is not equal to the old, set output parameter *pbSkip
+** to 1 before returning. Otherwise, leave it unchanged.
+**
+** Return SQLITE_OK if successful or if no reseek was required, or an
+** error code if an error occurred.
+*/
+static int fts5CursorReseek(Fts5Cursor *pCsr, int *pbSkip){
+  int rc = SQLITE_OK;
+  assert( *pbSkip==0 );
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_RESEEK) ){
+    Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+    int bDesc = pCsr->bDesc;
+    i64 iRowid = sqlite3Fts5ExprRowid(pCsr->pExpr);
+
+    rc = sqlite3Fts5ExprFirst(pCsr->pExpr, pTab->p.pIndex, iRowid, bDesc);
+    if( rc==SQLITE_OK &&  iRowid!=sqlite3Fts5ExprRowid(pCsr->pExpr) ){
+      *pbSkip = 1;
+    }
+
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_RESEEK);
+    fts5CsrNewrow(pCsr);
+    if( sqlite3Fts5ExprEof(pCsr->pExpr) ){
+      CsrFlagSet(pCsr, FTS5CSR_EOF);
+      *pbSkip = 1;
+    }
+  }
+  return rc;
+}
+
+
+/*
+** Advance the cursor to the next row in the table that matches the
+** search criteria.
+**
+** Return SQLITE_OK if nothing goes wrong.  SQLITE_OK is returned
+** even if we reach end-of-file.  The fts5EofMethod() will be called
+** subsequently to determine whether or not an EOF was hit.
+*/
+static int fts5NextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int rc;
+
+  assert( (pCsr->ePlan<3)==
+          (pCsr->ePlan==FTS5_PLAN_MATCH || pCsr->ePlan==FTS5_PLAN_SOURCE)
+  );
+  assert( !CsrFlagTest(pCsr, FTS5CSR_EOF) );
+
+  /* If this cursor uses FTS5_PLAN_MATCH and this is a tokendata=1 table,
+  ** clear any token mappings accumulated at the fts5_index.c level. In
+  ** other cases, specifically FTS5_PLAN_SOURCE and FTS5_PLAN_SORTED_MATCH,
+  ** we need to retain the mappings for the entire query.  */
+  if( pCsr->ePlan==FTS5_PLAN_MATCH
+   && ((Fts5Table*)pCursor->pVtab)->pConfig->bTokendata
+  ){
+    sqlite3Fts5ExprClearTokens(pCsr->pExpr);
+  }
+
+  if( pCsr->ePlan<3 ){
+    int bSkip = 0;
+    if( (rc = fts5CursorReseek(pCsr, &bSkip)) || bSkip ) return rc;
+    rc = sqlite3Fts5ExprNext(pCsr->pExpr, pCsr->iLastRowid);
+    CsrFlagSet(pCsr, sqlite3Fts5ExprEof(pCsr->pExpr));
+    fts5CsrNewrow(pCsr);
+  }else{
+    switch( pCsr->ePlan ){
+      case FTS5_PLAN_SPECIAL: {
+        CsrFlagSet(pCsr, FTS5CSR_EOF);
+        rc = SQLITE_OK;
+        break;
+      }
+
+      case FTS5_PLAN_SORTED_MATCH: {
+        rc = fts5SorterNext(pCsr);
+        break;
+      }
+
+      default: {
+        Fts5Config *pConfig = ((Fts5Table*)pCursor->pVtab)->pConfig;
+        pConfig->bLock++;
+        rc = sqlite3_step(pCsr->pStmt);
+        pConfig->bLock--;
+        if( rc!=SQLITE_ROW ){
+          CsrFlagSet(pCsr, FTS5CSR_EOF);
+          rc = sqlite3_reset(pCsr->pStmt);
+          if( rc!=SQLITE_OK ){
+            pCursor->pVtab->zErrMsg = sqlite3_mprintf(
+                "%s", sqlite3_errmsg(pConfig->db)
+            );
+          }
+        }else{
+          rc = SQLITE_OK;
+          CsrFlagSet(pCsr, FTS5CSR_REQUIRE_DOCSIZE);
+        }
+        break;
+      }
+    }
+  }
+
+  return rc;
+}
+
+
+static int fts5PrepareStatement(
+  sqlite3_stmt **ppStmt,
+  Fts5Config *pConfig,
+  const char *zFmt,
+  ...
+){
+  sqlite3_stmt *pRet = 0;
+  int rc;
+  char *zSql;
+  va_list ap;
+
+  va_start(ap, zFmt);
+  zSql = sqlite3_vmprintf(zFmt, ap);
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_prepare_v3(pConfig->db, zSql, -1,
+                            SQLITE_PREPARE_PERSISTENT, &pRet, 0);
+    if( rc!=SQLITE_OK ){
+      sqlite3Fts5ConfigErrmsg(pConfig, "%s", sqlite3_errmsg(pConfig->db));
+    }
+    sqlite3_free(zSql);
+  }
+
+  va_end(ap);
+  *ppStmt = pRet;
+  return rc;
+}
+
+static int fts5CursorFirstSorted(
+  Fts5FullTable *pTab,
+  Fts5Cursor *pCsr,
+  int bDesc
+){
+  Fts5Config *pConfig = pTab->p.pConfig;
+  Fts5Sorter *pSorter;
+  int nPhrase;
+  sqlite3_int64 nByte;
+  int rc;
+  const char *zRank = pCsr->zRank;
+  const char *zRankArgs = pCsr->zRankArgs;
+
+  nPhrase = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+  nByte = sizeof(Fts5Sorter) + sizeof(int) * (nPhrase-1);
+  pSorter = (Fts5Sorter*)sqlite3_malloc64(nByte);
+  if( pSorter==0 ) return SQLITE_NOMEM;
+  memset(pSorter, 0, (size_t)nByte);
+  pSorter->nIdx = nPhrase;
+
+  /* TODO: It would be better to have some system for reusing statement
+  ** handles here, rather than preparing a new one for each query. But that
+  ** is not possible as SQLite reference counts the virtual table objects.
+  ** And since the statement required here reads from this very virtual
+  ** table, saving it creates a circular reference.
+  **
+  ** If SQLite a built-in statement cache, this wouldn't be a problem. */
+  rc = fts5PrepareStatement(&pSorter->pStmt, pConfig,
+      "SELECT rowid, rank FROM %Q.%Q ORDER BY %s(\"%w\"%s%s) %s",
+      pConfig->zDb, pConfig->zName, zRank, pConfig->zName,
+      (zRankArgs ? ", " : ""),
+      (zRankArgs ? zRankArgs : ""),
+      bDesc ? "DESC" : "ASC"
+  );
+
+  pCsr->pSorter = pSorter;
+  if( rc==SQLITE_OK ){
+    assert( pTab->pSortCsr==0 );
+    pTab->pSortCsr = pCsr;
+    rc = fts5SorterNext(pCsr);
+    pTab->pSortCsr = 0;
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_finalize(pSorter->pStmt);
+    sqlite3_free(pSorter);
+    pCsr->pSorter = 0;
+  }
+
+  return rc;
+}
+
+static int fts5CursorFirst(Fts5FullTable *pTab, Fts5Cursor *pCsr, int bDesc){
+  int rc;
+  Fts5Expr *pExpr = pCsr->pExpr;
+  rc = sqlite3Fts5ExprFirst(pExpr, pTab->p.pIndex, pCsr->iFirstRowid, bDesc);
+  if( sqlite3Fts5ExprEof(pExpr) ){
+    CsrFlagSet(pCsr, FTS5CSR_EOF);
+  }
+  fts5CsrNewrow(pCsr);
+  return rc;
+}
+
+/*
+** Process a "special" query. A special query is identified as one with a
+** MATCH expression that begins with a '*' character. The remainder of
+** the text passed to the MATCH operator are used as  the special query
+** parameters.
+*/
+static int fts5SpecialMatch(
+  Fts5FullTable *pTab,
+  Fts5Cursor *pCsr,
+  const char *zQuery
+){
+  int rc = SQLITE_OK;             /* Return code */
+  const char *z = zQuery;         /* Special query text */
+  int n;                          /* Number of bytes in text at z */
+
+  while( z[0]==' ' ) z++;
+  for(n=0; z[n] && z[n]!=' '; n++);
+
+  assert( pTab->p.base.zErrMsg==0 );
+  pCsr->ePlan = FTS5_PLAN_SPECIAL;
+
+  if( n==5 && 0==sqlite3_strnicmp("reads", z, n) ){
+    pCsr->iSpecial = sqlite3Fts5IndexReads(pTab->p.pIndex);
+  }
+  else if( n==2 && 0==sqlite3_strnicmp("id", z, n) ){
+    pCsr->iSpecial = pCsr->iCsrId;
+  }
+  else{
+    /* An unrecognized directive. Return an error message. */
+    pTab->p.base.zErrMsg = sqlite3_mprintf("unknown special query: %.*s", n, z);
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+/*
+** Search for an auxiliary function named zName that can be used with table
+** pTab. If one is found, return a pointer to the corresponding Fts5Auxiliary
+** structure. Otherwise, if no such function exists, return NULL.
+*/
+static Fts5Auxiliary *fts5FindAuxiliary(Fts5FullTable *pTab, const char *zName){
+  Fts5Auxiliary *pAux;
+
+  for(pAux=pTab->pGlobal->pAux; pAux; pAux=pAux->pNext){
+    if( sqlite3_stricmp(zName, pAux->zFunc)==0 ) return pAux;
+  }
+
+  /* No function of the specified name was found. Return 0. */
+  return 0;
+}
+
+
+static int fts5FindRankFunction(Fts5Cursor *pCsr){
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  Fts5Config *pConfig = pTab->p.pConfig;
+  int rc = SQLITE_OK;
+  Fts5Auxiliary *pAux = 0;
+  const char *zRank = pCsr->zRank;
+  const char *zRankArgs = pCsr->zRankArgs;
+
+  if( zRankArgs ){
+    char *zSql = sqlite3Fts5Mprintf(&rc, "SELECT %s", zRankArgs);
+    if( zSql ){
+      sqlite3_stmt *pStmt = 0;
+      rc = sqlite3_prepare_v3(pConfig->db, zSql, -1,
+                              SQLITE_PREPARE_PERSISTENT, &pStmt, 0);
+      sqlite3_free(zSql);
+      assert( rc==SQLITE_OK || pCsr->pRankArgStmt==0 );
+      if( rc==SQLITE_OK ){
+        if( SQLITE_ROW==sqlite3_step(pStmt) ){
+          sqlite3_int64 nByte;
+          pCsr->nRankArg = sqlite3_column_count(pStmt);
+          nByte = sizeof(sqlite3_value*)*pCsr->nRankArg;
+          pCsr->apRankArg = (sqlite3_value**)sqlite3Fts5MallocZero(&rc, nByte);
+          if( rc==SQLITE_OK ){
+            int i;
+            for(i=0; i<pCsr->nRankArg; i++){
+              pCsr->apRankArg[i] = sqlite3_column_value(pStmt, i);
+            }
+          }
+          pCsr->pRankArgStmt = pStmt;
+        }else{
+          rc = sqlite3_finalize(pStmt);
+          assert( rc!=SQLITE_OK );
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    pAux = fts5FindAuxiliary(pTab, zRank);
+    if( pAux==0 ){
+      assert( pTab->p.base.zErrMsg==0 );
+      pTab->p.base.zErrMsg = sqlite3_mprintf("no such function: %s", zRank);
+      rc = SQLITE_ERROR;
+    }
+  }
+
+  pCsr->pRank = pAux;
+  return rc;
+}
+
+
+static int fts5CursorParseRank(
+  Fts5Config *pConfig,
+  Fts5Cursor *pCsr,
+  sqlite3_value *pRank
+){
+  int rc = SQLITE_OK;
+  if( pRank ){
+    const char *z = (const char*)sqlite3_value_text(pRank);
+    char *zRank = 0;
+    char *zRankArgs = 0;
+
+    if( z==0 ){
+      if( sqlite3_value_type(pRank)==SQLITE_NULL ) rc = SQLITE_ERROR;
+    }else{
+      rc = sqlite3Fts5ConfigParseRank(z, &zRank, &zRankArgs);
+    }
+    if( rc==SQLITE_OK ){
+      pCsr->zRank = zRank;
+      pCsr->zRankArgs = zRankArgs;
+      CsrFlagSet(pCsr, FTS5CSR_FREE_ZRANK);
+    }else if( rc==SQLITE_ERROR ){
+      pCsr->base.pVtab->zErrMsg = sqlite3_mprintf(
+          "parse error in rank function: %s", z
+      );
+    }
+  }else{
+    if( pConfig->zRank ){
+      pCsr->zRank = (char*)pConfig->zRank;
+      pCsr->zRankArgs = (char*)pConfig->zRankArgs;
+    }else{
+      pCsr->zRank = (char*)FTS5_DEFAULT_RANK;
+      pCsr->zRankArgs = 0;
+    }
+  }
+  return rc;
+}
+
+static i64 fts5GetRowidLimit(sqlite3_value *pVal, i64 iDefault){
+  if( pVal ){
+    int eType = sqlite3_value_numeric_type(pVal);
+    if( eType==SQLITE_INTEGER ){
+      return sqlite3_value_int64(pVal);
+    }
+  }
+  return iDefault;
+}
+
+/*
+** Set the error message on the virtual table passed as the first argument.
+*/
+static void fts5SetVtabError(Fts5FullTable *p, const char *zFormat, ...){
+  va_list ap;                     /* ... printf arguments */
+  va_start(ap, zFormat);
+  sqlite3_free(p->p.base.zErrMsg);
+  p->p.base.zErrMsg = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+}
+
+/*
+** Arrange for subsequent calls to sqlite3Fts5Tokenize() to use the locale
+** specified by pLocale/nLocale. The buffer indicated by pLocale must remain
+** valid until after the final call to sqlite3Fts5Tokenize() that will use
+** the locale.
+*/
+static void sqlite3Fts5SetLocale(
+  Fts5Config *pConfig,
+  const char *zLocale,
+  int nLocale
+){
+  Fts5TokenizerConfig *pT = &pConfig->t;
+  pT->pLocale = zLocale;
+  pT->nLocale = nLocale;
+}
+
+/*
+** Clear any locale configured by an earlier call to sqlite3Fts5SetLocale().
+*/
+static void sqlite3Fts5ClearLocale(Fts5Config *pConfig){
+  sqlite3Fts5SetLocale(pConfig, 0, 0);
+}
+
+/*
+** Return true if the value passed as the only argument is an
+** fts5_locale() value.
+*/
+static int sqlite3Fts5IsLocaleValue(Fts5Config *pConfig, sqlite3_value *pVal){
+  int ret = 0;
+  if( sqlite3_value_type(pVal)==SQLITE_BLOB ){
+    /* Call sqlite3_value_bytes() after sqlite3_value_blob() in this case.
+    ** If the blob was created using zeroblob(), then sqlite3_value_blob()
+    ** may call malloc(). If this malloc() fails, then the values returned
+    ** by both value_blob() and value_bytes() will be 0. If value_bytes() were
+    ** called first, then the NULL pointer returned by value_blob() might
+    ** be dereferenced.  */
+    const u8 *pBlob = sqlite3_value_blob(pVal);
+    int nBlob = sqlite3_value_bytes(pVal);
+    if( nBlob>FTS5_LOCALE_HDR_SIZE
+     && 0==memcmp(pBlob, FTS5_LOCALE_HDR(pConfig), FTS5_LOCALE_HDR_SIZE)
+    ){
+      ret = 1;
+    }
+  }
+  return ret;
+}
+
+/*
+** Value pVal is guaranteed to be an fts5_locale() value, according to
+** sqlite3Fts5IsLocaleValue(). This function extracts the text and locale
+** from the value and returns them separately.
+**
+** If successful, SQLITE_OK is returned and (*ppText) and (*ppLoc) set
+** to point to buffers containing the text and locale, as utf-8,
+** respectively. In this case output parameters (*pnText) and (*pnLoc) are
+** set to the sizes in bytes of these two buffers.
+**
+** Or, if an error occurs, then an SQLite error code is returned. The final
+** value of the four output parameters is undefined in this case.
+*/
+static int sqlite3Fts5DecodeLocaleValue(
+  sqlite3_value *pVal,
+  const char **ppText,
+  int *pnText,
+  const char **ppLoc,
+  int *pnLoc
+){
+  const char *p = sqlite3_value_blob(pVal);
+  int n = sqlite3_value_bytes(pVal);
+  int nLoc = 0;
+
+  assert( sqlite3_value_type(pVal)==SQLITE_BLOB );
+  assert( n>FTS5_LOCALE_HDR_SIZE );
+
+  for(nLoc=FTS5_LOCALE_HDR_SIZE; p[nLoc]; nLoc++){
+    if( nLoc==(n-1) ){
+      return SQLITE_MISMATCH;
+    }
+  }
+  *ppLoc = &p[FTS5_LOCALE_HDR_SIZE];
+  *pnLoc = nLoc - FTS5_LOCALE_HDR_SIZE;
+
+  *ppText = &p[nLoc+1];
+  *pnText = n - nLoc - 1;
+  return SQLITE_OK;
+}
+
+/*
+** Argument pVal is the text of a full-text search expression. It may or
+** may not have been wrapped by fts5_locale(). This function extracts
+** the text of the expression, and sets output variable (*pzText) to
+** point to a nul-terminated buffer containing the expression.
+**
+** If pVal was an fts5_locale() value, then sqlite3Fts5SetLocale() is called
+** to set the tokenizer to use the specified locale.
+**
+** If output variable (*pbFreeAndReset) is set to true, then the caller
+** is required to (a) call sqlite3Fts5ClearLocale() to reset the tokenizer
+** locale, and (b) call sqlite3_free() to free (*pzText).
+*/
+static int fts5ExtractExprText(
+  Fts5Config *pConfig,            /* Fts5 configuration */
+  sqlite3_value *pVal,            /* Value to extract expression text from */
+  char **pzText,                  /* OUT: nul-terminated buffer of text */
+  int *pbFreeAndReset             /* OUT: Free (*pzText) and clear locale */
+){
+  int rc = SQLITE_OK;
+
+  if( sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+    const char *pText = 0;
+    int nText = 0;
+    const char *pLoc = 0;
+    int nLoc = 0;
+    rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+    *pzText = sqlite3Fts5Mprintf(&rc, "%.*s", nText, pText);
+    if( rc==SQLITE_OK ){
+      sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+    }
+    *pbFreeAndReset = 1;
+  }else{
+    *pzText = (char*)sqlite3_value_text(pVal);
+    *pbFreeAndReset = 0;
+  }
+
+  return rc;
+}
+
+
+/*
+** This is the xFilter interface for the virtual table.  See
+** the virtual table xFilter method documentation for additional
+** information.
+**
+** There are three possible query strategies:
+**
+**   1. Full-text search using a MATCH operator.
+**   2. A by-rowid lookup.
+**   3. A full-table scan.
+*/
+static int fts5FilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *idxStr,             /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCursor->pVtab);
+  Fts5Config *pConfig = pTab->p.pConfig;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int rc = SQLITE_OK;             /* Error code */
+  int bDesc;                      /* True if ORDER BY [rank|rowid] DESC */
+  int bOrderByRank;               /* True if ORDER BY rank */
+  sqlite3_value *pRank = 0;       /* rank MATCH ? expression (or NULL) */
+  sqlite3_value *pRowidEq = 0;    /* rowid = ? expression (or NULL) */
+  sqlite3_value *pRowidLe = 0;    /* rowid <= ? expression (or NULL) */
+  sqlite3_value *pRowidGe = 0;    /* rowid >= ? expression (or NULL) */
+  int iCol;                       /* Column on LHS of MATCH operator */
+  char **pzErrmsg = pConfig->pzErrmsg;
+  int bPrefixInsttoken = pConfig->bPrefixInsttoken;
+  int i;
+  int iIdxStr = 0;
+  Fts5Expr *pExpr = 0;
+
+  assert( pConfig->bLock==0 );
+  if( pCsr->ePlan ){
+    fts5FreeCursorComponents(pCsr);
+    memset(&pCsr->ePlan, 0, sizeof(Fts5Cursor) - ((u8*)&pCsr->ePlan-(u8*)pCsr));
+  }
+
+  assert( pCsr->pStmt==0 );
+  assert( pCsr->pExpr==0 );
+  assert( pCsr->csrflags==0 );
+  assert( pCsr->pRank==0 );
+  assert( pCsr->zRank==0 );
+  assert( pCsr->zRankArgs==0 );
+  assert( pTab->pSortCsr==0 || nVal==0 );
+
+  assert( pzErrmsg==0 || pzErrmsg==&pTab->p.base.zErrMsg );
+  pConfig->pzErrmsg = &pTab->p.base.zErrMsg;
+
+  /* Decode the arguments passed through to this function. */
+  for(i=0; i<nVal; i++){
+    switch( idxStr[iIdxStr++] ){
+      case 'r':
+        pRank = apVal[i];
+        break;
+      case 'M': {
+        char *zText = 0;
+        int bFreeAndReset = 0;
+        int bInternal = 0;
+
+        rc = fts5ExtractExprText(pConfig, apVal[i], &zText, &bFreeAndReset);
+        if( rc!=SQLITE_OK ) goto filter_out;
+        if( zText==0 ) zText = "";
+        if( sqlite3_value_subtype(apVal[i])==FTS5_INSTTOKEN_SUBTYPE ){
+          pConfig->bPrefixInsttoken = 1;
+        }
+
+        iCol = 0;
+        do{
+          iCol = iCol*10 + (idxStr[iIdxStr]-'0');
+          iIdxStr++;
+        }while( idxStr[iIdxStr]>='0' && idxStr[iIdxStr]<='9' );
+
+        if( zText[0]=='*' ){
+          /* The user has issued a query of the form "MATCH '*...'". This
+          ** indicates that the MATCH expression is not a full text query,
+          ** but a request for an internal parameter.  */
+          rc = fts5SpecialMatch(pTab, pCsr, &zText[1]);
+          bInternal = 1;
+        }else{
+          char **pzErr = &pTab->p.base.zErrMsg;
+          rc = sqlite3Fts5ExprNew(pConfig, 0, iCol, zText, &pExpr, pzErr);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5ExprAnd(&pCsr->pExpr, pExpr);
+            pExpr = 0;
+          }
+        }
+
+        if( bFreeAndReset ){
+          sqlite3_free(zText);
+          sqlite3Fts5ClearLocale(pConfig);
+        }
+
+        if( bInternal || rc!=SQLITE_OK ) goto filter_out;
+
+        break;
+      }
+      case 'L':
+      case 'G': {
+        int bGlob = (idxStr[iIdxStr-1]=='G');
+        const char *zText = (const char*)sqlite3_value_text(apVal[i]);
+        iCol = 0;
+        do{
+          iCol = iCol*10 + (idxStr[iIdxStr]-'0');
+          iIdxStr++;
+        }while( idxStr[iIdxStr]>='0' && idxStr[iIdxStr]<='9' );
+        if( zText ){
+          rc = sqlite3Fts5ExprPattern(pConfig, bGlob, iCol, zText, &pExpr);
+        }
+        if( rc==SQLITE_OK ){
+          rc = sqlite3Fts5ExprAnd(&pCsr->pExpr, pExpr);
+          pExpr = 0;
+        }
+        if( rc!=SQLITE_OK ) goto filter_out;
+        break;
+      }
+      case '=':
+        pRowidEq = apVal[i];
+        break;
+      case '<':
+        pRowidLe = apVal[i];
+        break;
+      default: assert( idxStr[iIdxStr-1]=='>' );
+        pRowidGe = apVal[i];
+        break;
+    }
+  }
+  bOrderByRank = ((idxNum & FTS5_BI_ORDER_RANK) ? 1 : 0);
+  pCsr->bDesc = bDesc = ((idxNum & FTS5_BI_ORDER_DESC) ? 1 : 0);
+
+  /* Set the cursor upper and lower rowid limits. Only some strategies
+  ** actually use them. This is ok, as the xBestIndex() method leaves the
+  ** sqlite3_index_constraint.omit flag clear for range constraints
+  ** on the rowid field.  */
+  if( pRowidEq ){
+    pRowidLe = pRowidGe = pRowidEq;
+  }
+  if( bDesc ){
+    pCsr->iFirstRowid = fts5GetRowidLimit(pRowidLe, LARGEST_INT64);
+    pCsr->iLastRowid = fts5GetRowidLimit(pRowidGe, SMALLEST_INT64);
+  }else{
+    pCsr->iLastRowid = fts5GetRowidLimit(pRowidLe, LARGEST_INT64);
+    pCsr->iFirstRowid = fts5GetRowidLimit(pRowidGe, SMALLEST_INT64);
+  }
+
+  rc = sqlite3Fts5IndexLoadConfig(pTab->p.pIndex);
+  if( rc!=SQLITE_OK ) goto filter_out;
+
+  if( pTab->pSortCsr ){
+    /* If pSortCsr is non-NULL, then this call is being made as part of
+    ** processing for a "... MATCH <expr> ORDER BY rank" query (ePlan is
+    ** set to FTS5_PLAN_SORTED_MATCH). pSortCsr is the cursor that will
+    ** return results to the user for this query. The current cursor
+    ** (pCursor) is used to execute the query issued by function
+    ** fts5CursorFirstSorted() above.  */
+    assert( pRowidEq==0 && pRowidLe==0 && pRowidGe==0 && pRank==0 );
+    assert( nVal==0 && bOrderByRank==0 && bDesc==0 );
+    assert( pCsr->iLastRowid==LARGEST_INT64 );
+    assert( pCsr->iFirstRowid==SMALLEST_INT64 );
+    if( pTab->pSortCsr->bDesc ){
+      pCsr->iLastRowid = pTab->pSortCsr->iFirstRowid;
+      pCsr->iFirstRowid = pTab->pSortCsr->iLastRowid;
+    }else{
+      pCsr->iLastRowid = pTab->pSortCsr->iLastRowid;
+      pCsr->iFirstRowid = pTab->pSortCsr->iFirstRowid;
+    }
+    pCsr->ePlan = FTS5_PLAN_SOURCE;
+    pCsr->pExpr = pTab->pSortCsr->pExpr;
+    rc = fts5CursorFirst(pTab, pCsr, bDesc);
+  }else if( pCsr->pExpr ){
+    assert( rc==SQLITE_OK );
+    rc = fts5CursorParseRank(pConfig, pCsr, pRank);
+    if( rc==SQLITE_OK ){
+      if( bOrderByRank ){
+        pCsr->ePlan = FTS5_PLAN_SORTED_MATCH;
+        rc = fts5CursorFirstSorted(pTab, pCsr, bDesc);
+      }else{
+        pCsr->ePlan = FTS5_PLAN_MATCH;
+        rc = fts5CursorFirst(pTab, pCsr, bDesc);
+      }
+    }
+  }else if( pConfig->zContent==0 ){
+    fts5SetVtabError(pTab,"%s: table does not support scanning",pConfig->zName);
+    rc = SQLITE_ERROR;
+  }else{
+    /* This is either a full-table scan (ePlan==FTS5_PLAN_SCAN) or a lookup
+    ** by rowid (ePlan==FTS5_PLAN_ROWID).  */
+    pCsr->ePlan = (pRowidEq ? FTS5_PLAN_ROWID : FTS5_PLAN_SCAN);
+    rc = sqlite3Fts5StorageStmt(
+        pTab->pStorage, fts5StmtType(pCsr), &pCsr->pStmt, &pTab->p.base.zErrMsg
+    );
+    if( rc==SQLITE_OK ){
+      if( pRowidEq!=0 ){
+        assert( pCsr->ePlan==FTS5_PLAN_ROWID );
+        sqlite3_bind_value(pCsr->pStmt, 1, pRowidEq);
+      }else{
+        sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iFirstRowid);
+        sqlite3_bind_int64(pCsr->pStmt, 2, pCsr->iLastRowid);
+      }
+      rc = fts5NextMethod(pCursor);
+    }
+  }
+
+ filter_out:
+  sqlite3Fts5ExprFree(pExpr);
+  pConfig->pzErrmsg = pzErrmsg;
+  pConfig->bPrefixInsttoken = bPrefixInsttoken;
+  return rc;
+}
+
+/*
+** This is the xEof method of the virtual table. SQLite calls this
+** routine to find out if it has reached the end of a result set.
+*/
+static int fts5EofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  return (CsrFlagTest(pCsr, FTS5CSR_EOF) ? 1 : 0);
+}
+
+/*
+** Return the rowid that the cursor currently points to.
+*/
+static i64 fts5CursorRowid(Fts5Cursor *pCsr){
+  assert( pCsr->ePlan==FTS5_PLAN_MATCH
+       || pCsr->ePlan==FTS5_PLAN_SORTED_MATCH
+       || pCsr->ePlan==FTS5_PLAN_SOURCE
+       || pCsr->ePlan==FTS5_PLAN_SCAN
+       || pCsr->ePlan==FTS5_PLAN_ROWID
+  );
+  if( pCsr->pSorter ){
+    return pCsr->pSorter->iRowid;
+  }else if( pCsr->ePlan>=FTS5_PLAN_SCAN ){
+    return sqlite3_column_int64(pCsr->pStmt, 0);
+  }else{
+    return sqlite3Fts5ExprRowid(pCsr->pExpr);
+  }
+}
+
+/*
+** This is the xRowid method. The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set. fts5
+** exposes %_content.rowid as the rowid for the virtual table. The
+** rowid should be written to *pRowid.
+*/
+static int fts5RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int ePlan = pCsr->ePlan;
+
+  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );
+  if( ePlan==FTS5_PLAN_SPECIAL ){
+    *pRowid = 0;
+  }else{
+    *pRowid = fts5CursorRowid(pCsr);
+  }
+
+  return SQLITE_OK;
+}
+
+
+/*
+** If the cursor requires seeking (bSeekRequired flag is set), seek it.
+** Return SQLITE_OK if no error occurs, or an SQLite error code otherwise.
+**
+** If argument bErrormsg is true and an error occurs, an error message may
+** be left in sqlite3_vtab.zErrMsg.
+*/
+static int fts5SeekCursor(Fts5Cursor *pCsr, int bErrormsg){
+  int rc = SQLITE_OK;
+
+  /* If the cursor does not yet have a statement handle, obtain one now. */
+  if( pCsr->pStmt==0 ){
+    Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+    int eStmt = fts5StmtType(pCsr);
+    rc = sqlite3Fts5StorageStmt(
+        pTab->pStorage, eStmt, &pCsr->pStmt, (bErrormsg?&pTab->p.base.zErrMsg:0)
+    );
+    assert( rc!=SQLITE_OK || pTab->p.base.zErrMsg==0 );
+    assert( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) );
+  }
+
+  if( rc==SQLITE_OK && CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) ){
+    Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+    assert( pCsr->pExpr );
+    sqlite3_reset(pCsr->pStmt);
+    sqlite3_bind_int64(pCsr->pStmt, 1, fts5CursorRowid(pCsr));
+    pTab->pConfig->bLock++;
+    rc = sqlite3_step(pCsr->pStmt);
+    pTab->pConfig->bLock--;
+    if( rc==SQLITE_ROW ){
+      rc = SQLITE_OK;
+      CsrFlagClear(pCsr, FTS5CSR_REQUIRE_CONTENT);
+    }else{
+      rc = sqlite3_reset(pCsr->pStmt);
+      if( rc==SQLITE_OK ){
+        rc = FTS5_CORRUPT;
+        fts5SetVtabError((Fts5FullTable*)pTab,
+            "fts5: missing row %lld from content table %s",
+            fts5CursorRowid(pCsr),
+            pTab->pConfig->zContent
+        );
+      }else if( pTab->pConfig->pzErrmsg ){
+        fts5SetVtabError((Fts5FullTable*)pTab,
+            "%s", sqlite3_errmsg(pTab->pConfig->db)
+        );
+      }
+    }
+  }
+  return rc;
+}
+
+/*
+** This function is called to handle an FTS INSERT command. In other words,
+** an INSERT statement of the form:
+**
+**     INSERT INTO fts(fts) VALUES($pCmd)
+**     INSERT INTO fts(fts, rank) VALUES($pCmd, $pVal)
+**
+** Argument pVal is the value assigned to column "fts" by the INSERT
+** statement. This function returns SQLITE_OK if successful, or an SQLite
+** error code if an error occurs.
+**
+** The commands implemented by this function are documented in the "Special
+** INSERT Directives" section of the documentation. It should be updated if
+** more commands are added to this function.
+*/
+static int fts5SpecialInsert(
+  Fts5FullTable *pTab,            /* Fts5 table object */
+  const char *zCmd,               /* Text inserted into table-name column */
+  sqlite3_value *pVal             /* Value inserted into rank column */
+){
+  Fts5Config *pConfig = pTab->p.pConfig;
+  int rc = SQLITE_OK;
+  int bError = 0;
+  int bLoadConfig = 0;
+
+  if( 0==sqlite3_stricmp("delete-all", zCmd) ){
+    if( pConfig->eContent==FTS5_CONTENT_NORMAL ){
+      fts5SetVtabError(pTab,
+          "'delete-all' may only be used with a "
+          "contentless or external content fts5 table"
+      );
+      rc = SQLITE_ERROR;
+    }else{
+      rc = sqlite3Fts5StorageDeleteAll(pTab->pStorage);
+    }
+    bLoadConfig = 1;
+  }else if( 0==sqlite3_stricmp("rebuild", zCmd) ){
+    if( fts5IsContentless(pTab, 1) ){
+      fts5SetVtabError(pTab,
+          "'rebuild' may not be used with a contentless fts5 table"
+      );
+      rc = SQLITE_ERROR;
+    }else{
+      rc = sqlite3Fts5StorageRebuild(pTab->pStorage);
+    }
+    bLoadConfig = 1;
+  }else if( 0==sqlite3_stricmp("optimize", zCmd) ){
+    rc = sqlite3Fts5StorageOptimize(pTab->pStorage);
+  }else if( 0==sqlite3_stricmp("merge", zCmd) ){
+    int nMerge = sqlite3_value_int(pVal);
+    rc = sqlite3Fts5StorageMerge(pTab->pStorage, nMerge);
+  }else if( 0==sqlite3_stricmp("integrity-check", zCmd) ){
+    int iArg = sqlite3_value_int(pVal);
+    rc = sqlite3Fts5StorageIntegrity(pTab->pStorage, iArg);
+#ifdef SQLITE_DEBUG
+  }else if( 0==sqlite3_stricmp("prefix-index", zCmd) ){
+    pConfig->bPrefixIndex = sqlite3_value_int(pVal);
+#endif
+  }else if( 0==sqlite3_stricmp("flush", zCmd) ){
+    rc = sqlite3Fts5FlushToDisk(&pTab->p);
+  }else{
+    rc = sqlite3Fts5FlushToDisk(&pTab->p);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5IndexLoadConfig(pTab->p.pIndex);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5ConfigSetValue(pTab->p.pConfig, zCmd, pVal, &bError);
+    }
+    if( rc==SQLITE_OK ){
+      if( bError ){
+        rc = SQLITE_ERROR;
+      }else{
+        rc = sqlite3Fts5StorageConfigValue(pTab->pStorage, zCmd, pVal, 0);
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK && bLoadConfig ){
+    pTab->p.pConfig->iCookie--;
+    rc = sqlite3Fts5IndexLoadConfig(pTab->p.pIndex);
+  }
+
+  return rc;
+}
+
+static int fts5SpecialDelete(
+  Fts5FullTable *pTab,
+  sqlite3_value **apVal
+){
+  int rc = SQLITE_OK;
+  int eType1 = sqlite3_value_type(apVal[1]);
+  if( eType1==SQLITE_INTEGER ){
+    sqlite3_int64 iDel = sqlite3_value_int64(apVal[1]);
+    rc = sqlite3Fts5StorageDelete(pTab->pStorage, iDel, &apVal[2], 0);
+  }
+  return rc;
+}
+
+static void fts5StorageInsert(
+  int *pRc,
+  Fts5FullTable *pTab,
+  sqlite3_value **apVal,
+  i64 *piRowid
+){
+  int rc = *pRc;
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageContentInsert(pTab->pStorage, 0, apVal, piRowid);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageIndexInsert(pTab->pStorage, apVal, *piRowid);
+  }
+  *pRc = rc;
+}
+
+/*
+**
+** This function is called when the user attempts an UPDATE on a contentless
+** table. Parameter bRowidModified is true if the UPDATE statement modifies
+** the rowid value. Parameter apVal[] contains the new values for each user
+** defined column of the fts5 table. pConfig is the configuration object of the
+** table being updated (guaranteed to be contentless). The contentless_delete=1
+** and contentless_unindexed=1 options may or may not be set.
+**
+** This function returns SQLITE_OK if the UPDATE can go ahead, or an SQLite
+** error code if it cannot. In this case an error message is also loaded into
+** pConfig. Output parameter (*pbContent) is set to true if the caller should
+** update the %_content table only - not the FTS index or any other shadow
+** table. This occurs when an UPDATE modifies only UNINDEXED columns of the
+** table.
+**
+** An UPDATE may proceed if:
+**
+**   * The only columns modified are UNINDEXED columns, or
+**
+**   * The contentless_delete=1 option was specified and all of the indexed
+**     columns (not a subset) have been modified.
+*/
+static int fts5ContentlessUpdate(
+  Fts5Config *pConfig,
+  sqlite3_value **apVal,
+  int bRowidModified,
+  int *pbContent
+){
+  int ii;
+  int bSeenIndex = 0;             /* Have seen modified indexed column */
+  int bSeenIndexNC = 0;           /* Have seen unmodified indexed column */
+  int rc = SQLITE_OK;
+
+  for(ii=0; ii<pConfig->nCol; ii++){
+    if( pConfig->abUnindexed[ii]==0 ){
+      if( sqlite3_value_nochange(apVal[ii]) ){
+        bSeenIndexNC++;
+      }else{
+        bSeenIndex++;
+      }
+    }
+  }
+
+  if( bSeenIndex==0 && bRowidModified==0 ){
+    *pbContent = 1;
+  }else{
+    if( bSeenIndexNC || pConfig->bContentlessDelete==0 ){
+      rc = SQLITE_ERROR;
+      sqlite3Fts5ConfigErrmsg(pConfig,
+          (pConfig->bContentlessDelete ?
+          "%s a subset of columns on fts5 contentless-delete table: %s" :
+          "%s contentless fts5 table: %s")
+          , "cannot UPDATE", pConfig->zName
+      );
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is the implementation of the xUpdate callback used by
+** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
+** inserted, updated or deleted.
+**
+** A delete specifies a single argument - the rowid of the row to remove.
+**
+** Update and insert operations pass:
+**
+**   1. The "old" rowid, or NULL.
+**   2. The "new" rowid.
+**   3. Values for each of the nCol matchable columns.
+**   4. Values for the two hidden columns (<tablename> and "rank").
+*/
+static int fts5UpdateMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  Fts5Config *pConfig = pTab->p.pConfig;
+  int eType0;                     /* value_type() of apVal[0] */
+  int rc = SQLITE_OK;             /* Return code */
+
+  /* A transaction must be open when this is called. */
+  assert( pTab->ts.eState==1 || pTab->ts.eState==2 );
+
+  assert( pVtab->zErrMsg==0 );
+  assert( nArg==1 || nArg==(2+pConfig->nCol+2) );
+  assert( sqlite3_value_type(apVal[0])==SQLITE_INTEGER
+       || sqlite3_value_type(apVal[0])==SQLITE_NULL
+  );
+  assert( pTab->p.pConfig->pzErrmsg==0 );
+  if( pConfig->pgsz==0 ){
+    rc = sqlite3Fts5ConfigLoad(pTab->p.pConfig, pTab->p.pConfig->iCookie);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  pTab->p.pConfig->pzErrmsg = &pTab->p.base.zErrMsg;
+
+  /* Put any active cursors into REQUIRE_SEEK state. */
+  fts5TripCursors(pTab);
+
+  eType0 = sqlite3_value_type(apVal[0]);
+  if( eType0==SQLITE_NULL
+   && sqlite3_value_type(apVal[2+pConfig->nCol])!=SQLITE_NULL
+  ){
+    /* A "special" INSERT op. These are handled separately. */
+    const char *z = (const char*)sqlite3_value_text(apVal[2+pConfig->nCol]);
+    if( pConfig->eContent!=FTS5_CONTENT_NORMAL
+      && 0==sqlite3_stricmp("delete", z)
+    ){
+      if( pConfig->bContentlessDelete ){
+        fts5SetVtabError(pTab,
+            "'delete' may not be used with a contentless_delete=1 table"
+        );
+        rc = SQLITE_ERROR;
+      }else{
+        rc = fts5SpecialDelete(pTab, apVal);
+      }
+    }else{
+      rc = fts5SpecialInsert(pTab, z, apVal[2 + pConfig->nCol + 1]);
+    }
+  }else{
+    /* A regular INSERT, UPDATE or DELETE statement. The trick here is that
+    ** any conflict on the rowid value must be detected before any
+    ** modifications are made to the database file. There are 4 cases:
+    **
+    **   1) DELETE
+    **   2) UPDATE (rowid not modified)
+    **   3) UPDATE (rowid modified)
+    **   4) INSERT
+    **
+    ** Cases 3 and 4 may violate the rowid constraint.
+    */
+    int eConflict = SQLITE_ABORT;
+    if( pConfig->eContent==FTS5_CONTENT_NORMAL || pConfig->bContentlessDelete ){
+      eConflict = sqlite3_vtab_on_conflict(pConfig->db);
+    }
+
+    assert( eType0==SQLITE_INTEGER || eType0==SQLITE_NULL );
+    assert( nArg!=1 || eType0==SQLITE_INTEGER );
+
+    /* DELETE */
+    if( nArg==1 ){
+      /* It is only possible to DELETE from a contentless table if the
+      ** contentless_delete=1 flag is set. */
+      if( fts5IsContentless(pTab, 1) && pConfig->bContentlessDelete==0 ){
+        fts5SetVtabError(pTab,
+            "cannot DELETE from contentless fts5 table: %s", pConfig->zName
+        );
+        rc = SQLITE_ERROR;
+      }else{
+        i64 iDel = sqlite3_value_int64(apVal[0]);  /* Rowid to delete */
+        rc = sqlite3Fts5StorageDelete(pTab->pStorage, iDel, 0, 0);
+      }
+    }
+
+    /* INSERT or UPDATE */
+    else{
+      int eType1 = sqlite3_value_numeric_type(apVal[1]);
+
+      /* It is an error to write an fts5_locale() value to a table without
+      ** the locale=1 option. */
+      if( pConfig->bLocale==0 ){
+        int ii;
+        for(ii=0; ii<pConfig->nCol; ii++){
+          sqlite3_value *pVal = apVal[ii+2];
+          if( sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+            fts5SetVtabError(pTab, "fts5_locale() requires locale=1");
+            rc = SQLITE_MISMATCH;
+            goto update_out;
+          }
+        }
+      }
+
+      if( eType0!=SQLITE_INTEGER ){
+        /* An INSERT statement. If the conflict-mode is REPLACE, first remove
+        ** the current entry (if any). */
+        if( eConflict==SQLITE_REPLACE && eType1==SQLITE_INTEGER ){
+          i64 iNew = sqlite3_value_int64(apVal[1]);  /* Rowid to delete */
+          rc = sqlite3Fts5StorageDelete(pTab->pStorage, iNew, 0, 0);
+        }
+        fts5StorageInsert(&rc, pTab, apVal, pRowid);
+      }
+
+      /* UPDATE */
+      else{
+        Fts5Storage *pStorage = pTab->pStorage;
+        i64 iOld = sqlite3_value_int64(apVal[0]);  /* Old rowid */
+        i64 iNew = sqlite3_value_int64(apVal[1]);  /* New rowid */
+        int bContent = 0;         /* Content only update */
+
+        /* If this is a contentless table (including contentless_unindexed=1
+        ** tables), check if the UPDATE may proceed.  */
+        if( fts5IsContentless(pTab, 1) ){
+          rc = fts5ContentlessUpdate(pConfig, &apVal[2], iOld!=iNew, &bContent);
+          if( rc!=SQLITE_OK ) goto update_out;
+        }
+
+        if( eType1!=SQLITE_INTEGER ){
+          rc = SQLITE_MISMATCH;
+        }else if( iOld!=iNew ){
+          assert( bContent==0 );
+          if( eConflict==SQLITE_REPLACE ){
+            rc = sqlite3Fts5StorageDelete(pStorage, iOld, 0, 1);
+            if( rc==SQLITE_OK ){
+              rc = sqlite3Fts5StorageDelete(pStorage, iNew, 0, 0);
+            }
+            fts5StorageInsert(&rc, pTab, apVal, pRowid);
+          }else{
+            rc = sqlite3Fts5StorageFindDeleteRow(pStorage, iOld);
+            if( rc==SQLITE_OK ){
+              rc = sqlite3Fts5StorageContentInsert(pStorage, 0, apVal, pRowid);
+            }
+            if( rc==SQLITE_OK ){
+              rc = sqlite3Fts5StorageDelete(pStorage, iOld, 0, 0);
+            }
+            if( rc==SQLITE_OK ){
+              rc = sqlite3Fts5StorageIndexInsert(pStorage, apVal, *pRowid);
+            }
+          }
+        }else if( bContent ){
+          /* This occurs when an UPDATE on a contentless table affects *only*
+          ** UNINDEXED columns. This is a no-op for contentless_unindexed=0
+          ** tables, or a write to the %_content table only for =1 tables.  */
+          assert( fts5IsContentless(pTab, 1) );
+          rc = sqlite3Fts5StorageFindDeleteRow(pStorage, iOld);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5StorageContentInsert(pStorage, 1, apVal, pRowid);
+          }
+        }else{
+          rc = sqlite3Fts5StorageDelete(pStorage, iOld, 0, 1);
+          fts5StorageInsert(&rc, pTab, apVal, pRowid);
+        }
+        sqlite3Fts5StorageReleaseDeleteRow(pStorage);
+      }
+    }
+  }
+
+ update_out:
+  pTab->p.pConfig->pzErrmsg = 0;
+  return rc;
+}
+
+/*
+** Implementation of xSync() method.
+*/
+static int fts5SyncMethod(sqlite3_vtab *pVtab){
+  int rc;
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  fts5CheckTransactionState(pTab, FTS5_SYNC, 0);
+  pTab->p.pConfig->pzErrmsg = &pTab->p.base.zErrMsg;
+  rc = sqlite3Fts5FlushToDisk(&pTab->p);
+  pTab->p.pConfig->pzErrmsg = 0;
+  return rc;
+}
+
+/*
+** Implementation of xBegin() method.
+*/
+static int fts5BeginMethod(sqlite3_vtab *pVtab){
+  int rc = fts5NewTransaction((Fts5FullTable*)pVtab);
+  if( rc==SQLITE_OK ){
+    fts5CheckTransactionState((Fts5FullTable*)pVtab, FTS5_BEGIN, 0);
+  }
+  return rc;
+}
+
+/*
+** Implementation of xCommit() method. This is a no-op. The contents of
+** the pending-terms hash-table have already been flushed into the database
+** by fts5SyncMethod().
+*/
+static int fts5CommitMethod(sqlite3_vtab *pVtab){
+  UNUSED_PARAM(pVtab);  /* Call below is a no-op for NDEBUG builds */
+  fts5CheckTransactionState((Fts5FullTable*)pVtab, FTS5_COMMIT, 0);
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xRollback(). Discard the contents of the pending-terms
+** hash-table. Any changes made to the database are reverted by SQLite.
+*/
+static int fts5RollbackMethod(sqlite3_vtab *pVtab){
+  int rc;
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  fts5CheckTransactionState(pTab, FTS5_ROLLBACK, 0);
+  rc = sqlite3Fts5StorageRollback(pTab->pStorage);
+  pTab->p.pConfig->pgsz = 0;
+  return rc;
+}
+
+static int fts5CsrPoslist(Fts5Cursor*, int, const u8**, int*);
+
+static void *fts5ApiUserData(Fts5Context *pCtx){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return pCsr->pAux->pUserData;
+}
+
+static int fts5ApiColumnCount(Fts5Context *pCtx){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return ((Fts5Table*)(pCsr->base.pVtab))->pConfig->nCol;
+}
+
+static int fts5ApiColumnTotalSize(
+  Fts5Context *pCtx,
+  int iCol,
+  sqlite3_int64 *pnToken
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  return sqlite3Fts5StorageSize(pTab->pStorage, iCol, pnToken);
+}
+
+static int fts5ApiRowCount(Fts5Context *pCtx, i64 *pnRow){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  return sqlite3Fts5StorageRowCount(pTab->pStorage, pnRow);
+}
+
+/*
+** Implementation of xTokenize_v2() API.
+*/
+static int fts5ApiTokenize_v2(
+  Fts5Context *pCtx,
+  const char *pText, int nText,
+  const char *pLoc, int nLoc,
+  void *pUserData,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+  int rc = SQLITE_OK;
+
+  sqlite3Fts5SetLocale(pTab->pConfig, pLoc, nLoc);
+  rc = sqlite3Fts5Tokenize(pTab->pConfig,
+      FTS5_TOKENIZE_AUX, pText, nText, pUserData, xToken
+  );
+  sqlite3Fts5SetLocale(pTab->pConfig, 0, 0);
+
+  return rc;
+}
+
+/*
+** Implementation of xTokenize() API. This is just xTokenize_v2() with NULL/0
+** passed as the locale.
+*/
+static int fts5ApiTokenize(
+  Fts5Context *pCtx,
+  const char *pText, int nText,
+  void *pUserData,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  return fts5ApiTokenize_v2(pCtx, pText, nText, 0, 0, pUserData, xToken);
+}
+
+static int fts5ApiPhraseCount(Fts5Context *pCtx){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+}
+
+static int fts5ApiPhraseSize(Fts5Context *pCtx, int iPhrase){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return sqlite3Fts5ExprPhraseSize(pCsr->pExpr, iPhrase);
+}
+
+/*
+** Argument pStmt is an SQL statement of the type used by Fts5Cursor. This
+** function extracts the text value of column iCol of the current row.
+** Additionally, if there is an associated locale, it invokes
+** sqlite3Fts5SetLocale() to configure the tokenizer. In all cases the caller
+** should invoke sqlite3Fts5ClearLocale() to clear the locale at some point
+** after this function returns.
+**
+** If successful, (*ppText) is set to point to a buffer containing the text
+** value as utf-8 and SQLITE_OK returned. (*pnText) is set to the size of that
+** buffer in bytes. It is not guaranteed to be nul-terminated. If an error
+** occurs, an SQLite error code is returned. The final values of the two
+** output parameters are undefined in this case.
+*/
+static int fts5TextFromStmt(
+  Fts5Config *pConfig,
+  sqlite3_stmt *pStmt,
+  int iCol,
+  const char **ppText,
+  int *pnText
+){
+  sqlite3_value *pVal = sqlite3_column_value(pStmt, iCol+1);
+  const char *pLoc = 0;
+  int nLoc = 0;
+  int rc = SQLITE_OK;
+
+  if( pConfig->bLocale
+   && pConfig->eContent==FTS5_CONTENT_EXTERNAL
+   && sqlite3Fts5IsLocaleValue(pConfig, pVal)
+  ){
+    rc = sqlite3Fts5DecodeLocaleValue(pVal, ppText, pnText, &pLoc, &nLoc);
+  }else{
+    *ppText = (const char*)sqlite3_value_text(pVal);
+    *pnText = sqlite3_value_bytes(pVal);
+    if( pConfig->bLocale && pConfig->eContent==FTS5_CONTENT_NORMAL ){
+      pLoc = (const char*)sqlite3_column_text(pStmt, iCol+1+pConfig->nCol);
+      nLoc = sqlite3_column_bytes(pStmt, iCol+1+pConfig->nCol);
+    }
+  }
+  sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+  return rc;
+}
+
+static int fts5ApiColumnText(
+  Fts5Context *pCtx,
+  int iCol,
+  const char **pz,
+  int *pn
+){
+  int rc = SQLITE_OK;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+
+  assert( pCsr->ePlan!=FTS5_PLAN_SPECIAL );
+  if( iCol<0 || iCol>=pTab->pConfig->nCol ){
+    rc = SQLITE_RANGE;
+  }else if( fts5IsContentless((Fts5FullTable*)(pCsr->base.pVtab), 0) ){
+    *pz = 0;
+    *pn = 0;
+  }else{
+    rc = fts5SeekCursor(pCsr, 0);
+    if( rc==SQLITE_OK ){
+      rc = fts5TextFromStmt(pTab->pConfig, pCsr->pStmt, iCol, pz, pn);
+      sqlite3Fts5ClearLocale(pTab->pConfig);
+    }
+  }
+  return rc;
+}
+
+/*
+** This is called by various API functions - xInst, xPhraseFirst,
+** xPhraseFirstColumn etc. - to obtain the position list for phrase iPhrase
+** of the current row. This function works for both detail=full tables (in
+** which case the position-list was read from the fts index) or for other
+** detail= modes if the row content is available.
+*/
+static int fts5CsrPoslist(
+  Fts5Cursor *pCsr,               /* Fts5 cursor object */
+  int iPhrase,                    /* Phrase to find position list for */
+  const u8 **pa,                  /* OUT: Pointer to position list buffer */
+  int *pn                         /* OUT: Size of (*pa) in bytes */
+){
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+  int rc = SQLITE_OK;
+  int bLive = (pCsr->pSorter==0);
+
+  if( iPhrase<0 || iPhrase>=sqlite3Fts5ExprPhraseCount(pCsr->pExpr) ){
+    rc = SQLITE_RANGE;
+  }else if( pConfig->eDetail!=FTS5_DETAIL_FULL
+         && fts5IsContentless((Fts5FullTable*)pCsr->base.pVtab, 1)
+  ){
+    *pa = 0;
+    *pn = 0;
+    return SQLITE_OK;
+  }else if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_POSLIST) ){
+    if( pConfig->eDetail!=FTS5_DETAIL_FULL ){
+      Fts5PoslistPopulator *aPopulator;
+      int i;
+
+      aPopulator = sqlite3Fts5ExprClearPoslists(pCsr->pExpr, bLive);
+      if( aPopulator==0 ) rc = SQLITE_NOMEM;
+      if( rc==SQLITE_OK ){
+        rc = fts5SeekCursor(pCsr, 0);
+      }
+      for(i=0; i<pConfig->nCol && rc==SQLITE_OK; i++){
+        const char *z = 0;
+        int n = 0;
+        rc = fts5TextFromStmt(pConfig, pCsr->pStmt, i, &z, &n);
+        if( rc==SQLITE_OK ){
+          rc = sqlite3Fts5ExprPopulatePoslists(
+              pConfig, pCsr->pExpr, aPopulator, i, z, n
+          );
+        }
+        sqlite3Fts5ClearLocale(pConfig);
+      }
+      sqlite3_free(aPopulator);
+
+      if( pCsr->pSorter ){
+        sqlite3Fts5ExprCheckPoslists(pCsr->pExpr, pCsr->pSorter->iRowid);
+      }
+    }
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_POSLIST);
+  }
+
+  if( rc==SQLITE_OK ){
+    if( pCsr->pSorter && pConfig->eDetail==FTS5_DETAIL_FULL ){
+      Fts5Sorter *pSorter = pCsr->pSorter;
+      int i1 = (iPhrase==0 ? 0 : pSorter->aIdx[iPhrase-1]);
+      *pn = pSorter->aIdx[iPhrase] - i1;
+      *pa = &pSorter->aPoslist[i1];
+    }else{
+      *pn = sqlite3Fts5ExprPoslist(pCsr->pExpr, iPhrase, pa);
+    }
+  }else{
+    *pa = 0;
+    *pn = 0;
+  }
+
+  return rc;
+}
+
+/*
+** Ensure that the Fts5Cursor.nInstCount and aInst[] variables are populated
+** correctly for the current view. Return SQLITE_OK if successful, or an
+** SQLite error code otherwise.
+*/
+static int fts5CacheInstArray(Fts5Cursor *pCsr){
+  int rc = SQLITE_OK;
+  Fts5PoslistReader *aIter;       /* One iterator for each phrase */
+  int nIter;                      /* Number of iterators/phrases */
+  int nCol = ((Fts5Table*)pCsr->base.pVtab)->pConfig->nCol;
+
+  nIter = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+  if( pCsr->aInstIter==0 ){
+    sqlite3_int64 nByte = sizeof(Fts5PoslistReader) * nIter;
+    pCsr->aInstIter = (Fts5PoslistReader*)sqlite3Fts5MallocZero(&rc, nByte);
+  }
+  aIter = pCsr->aInstIter;
+
+  if( aIter ){
+    int nInst = 0;                /* Number instances seen so far */
+    int i;
+
+    /* Initialize all iterators */
+    for(i=0; i<nIter && rc==SQLITE_OK; i++){
+      const u8 *a;
+      int n;
+      rc = fts5CsrPoslist(pCsr, i, &a, &n);
+      if( rc==SQLITE_OK ){
+        sqlite3Fts5PoslistReaderInit(a, n, &aIter[i]);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      while( 1 ){
+        int *aInst;
+        int iBest = -1;
+        for(i=0; i<nIter; i++){
+          if( (aIter[i].bEof==0)
+              && (iBest<0 || aIter[i].iPos<aIter[iBest].iPos)
+            ){
+            iBest = i;
+          }
+        }
+        if( iBest<0 ) break;
+
+        nInst++;
+        if( nInst>=pCsr->nInstAlloc ){
+          int nNewSize = pCsr->nInstAlloc ? pCsr->nInstAlloc*2 : 32;
+          aInst = (int*)sqlite3_realloc64(
+              pCsr->aInst, nNewSize*sizeof(int)*3
+              );
+          if( aInst ){
+            pCsr->aInst = aInst;
+            pCsr->nInstAlloc = nNewSize;
+          }else{
+            nInst--;
+            rc = SQLITE_NOMEM;
+            break;
+          }
+        }
+
+        aInst = &pCsr->aInst[3 * (nInst-1)];
+        aInst[0] = iBest;
+        aInst[1] = FTS5_POS2COLUMN(aIter[iBest].iPos);
+        aInst[2] = FTS5_POS2OFFSET(aIter[iBest].iPos);
+        assert( aInst[1]>=0 );
+        if( aInst[1]>=nCol ){
+          rc = FTS5_CORRUPT;
+          break;
+        }
+        sqlite3Fts5PoslistReaderNext(&aIter[iBest]);
+      }
+    }
+
+    pCsr->nInstCount = nInst;
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_INST);
+  }
+  return rc;
+}
+
+static int fts5ApiInstCount(Fts5Context *pCtx, int *pnInst){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int rc = SQLITE_OK;
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_INST)==0
+   || SQLITE_OK==(rc = fts5CacheInstArray(pCsr)) ){
+    *pnInst = pCsr->nInstCount;
+  }
+  return rc;
+}
+
+static int fts5ApiInst(
+  Fts5Context *pCtx,
+  int iIdx,
+  int *piPhrase,
+  int *piCol,
+  int *piOff
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int rc = SQLITE_OK;
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_INST)==0
+   || SQLITE_OK==(rc = fts5CacheInstArray(pCsr))
+  ){
+    if( iIdx<0 || iIdx>=pCsr->nInstCount ){
+      rc = SQLITE_RANGE;
+    }else{
+      *piPhrase = pCsr->aInst[iIdx*3];
+      *piCol = pCsr->aInst[iIdx*3 + 1];
+      *piOff = pCsr->aInst[iIdx*3 + 2];
+    }
+  }
+  return rc;
+}
+
+static sqlite3_int64 fts5ApiRowid(Fts5Context *pCtx){
+  return fts5CursorRowid((Fts5Cursor*)pCtx);
+}
+
+static int fts5ColumnSizeCb(
+  void *pContext,                 /* Pointer to int */
+  int tflags,
+  const char *pUnused,            /* Buffer containing token */
+  int nUnused,                    /* Size of token in bytes */
+  int iUnused1,                   /* Start offset of token */
+  int iUnused2                    /* End offset of token */
+){
+  int *pCnt = (int*)pContext;
+  UNUSED_PARAM2(pUnused, nUnused);
+  UNUSED_PARAM2(iUnused1, iUnused2);
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 ){
+    (*pCnt)++;
+  }
+  return SQLITE_OK;
+}
+
+static int fts5ApiColumnSize(Fts5Context *pCtx, int iCol, int *pnToken){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  Fts5Config *pConfig = pTab->p.pConfig;
+  int rc = SQLITE_OK;
+
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_DOCSIZE) ){
+    if( pConfig->bColumnsize ){
+      i64 iRowid = fts5CursorRowid(pCsr);
+      rc = sqlite3Fts5StorageDocsize(pTab->pStorage, iRowid, pCsr->aColumnSize);
+    }else if( !pConfig->zContent || pConfig->eContent==FTS5_CONTENT_UNINDEXED ){
+      int i;
+      for(i=0; i<pConfig->nCol; i++){
+        if( pConfig->abUnindexed[i]==0 ){
+          pCsr->aColumnSize[i] = -1;
+        }
+      }
+    }else{
+      int i;
+      rc = fts5SeekCursor(pCsr, 0);
+      for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
+        if( pConfig->abUnindexed[i]==0 ){
+          const char *z = 0;
+          int n = 0;
+          pCsr->aColumnSize[i] = 0;
+          rc = fts5TextFromStmt(pConfig, pCsr->pStmt, i, &z, &n);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5Tokenize(pConfig, FTS5_TOKENIZE_AUX,
+                z, n, (void*)&pCsr->aColumnSize[i], fts5ColumnSizeCb
+            );
+          }
+          sqlite3Fts5ClearLocale(pConfig);
+        }
+      }
+    }
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_DOCSIZE);
+  }
+  if( iCol<0 ){
+    int i;
+    *pnToken = 0;
+    for(i=0; i<pConfig->nCol; i++){
+      *pnToken += pCsr->aColumnSize[i];
+    }
+  }else if( iCol<pConfig->nCol ){
+    *pnToken = pCsr->aColumnSize[iCol];
+  }else{
+    *pnToken = 0;
+    rc = SQLITE_RANGE;
+  }
+  return rc;
+}
+
+/*
+** Implementation of the xSetAuxdata() method.
+*/
+static int fts5ApiSetAuxdata(
+  Fts5Context *pCtx,              /* Fts5 context */
+  void *pPtr,                     /* Pointer to save as auxdata */
+  void(*xDelete)(void*)           /* Destructor for pPtr (or NULL) */
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Auxdata *pData;
+
+  /* Search through the cursors list of Fts5Auxdata objects for one that
+  ** corresponds to the currently executing auxiliary function.  */
+  for(pData=pCsr->pAuxdata; pData; pData=pData->pNext){
+    if( pData->pAux==pCsr->pAux ) break;
+  }
+
+  if( pData ){
+    if( pData->xDelete ){
+      pData->xDelete(pData->pPtr);
+    }
+  }else{
+    int rc = SQLITE_OK;
+    pData = (Fts5Auxdata*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Auxdata));
+    if( pData==0 ){
+      if( xDelete ) xDelete(pPtr);
+      return rc;
+    }
+    pData->pAux = pCsr->pAux;
+    pData->pNext = pCsr->pAuxdata;
+    pCsr->pAuxdata = pData;
+  }
+
+  pData->xDelete = xDelete;
+  pData->pPtr = pPtr;
+  return SQLITE_OK;
+}
+
+static void *fts5ApiGetAuxdata(Fts5Context *pCtx, int bClear){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Auxdata *pData;
+  void *pRet = 0;
+
+  for(pData=pCsr->pAuxdata; pData; pData=pData->pNext){
+    if( pData->pAux==pCsr->pAux ) break;
+  }
+
+  if( pData ){
+    pRet = pData->pPtr;
+    if( bClear ){
+      pData->pPtr = 0;
+      pData->xDelete = 0;
+    }
+  }
+
+  return pRet;
+}
+
+static void fts5ApiPhraseNext(
+  Fts5Context *pCtx,
+  Fts5PhraseIter *pIter,
+  int *piCol, int *piOff
+){
+  if( pIter->a>=pIter->b ){
+    *piCol = -1;
+    *piOff = -1;
+  }else{
+    int iVal;
+    pIter->a += fts5GetVarint32(pIter->a, iVal);
+    if( iVal==1 ){
+      /* Avoid returning a (*piCol) value that is too large for the table,
+      ** even if the position-list is corrupt. The caller might not be
+      ** expecting it.  */
+      int nCol = ((Fts5Table*)(((Fts5Cursor*)pCtx)->base.pVtab))->pConfig->nCol;
+      pIter->a += fts5GetVarint32(pIter->a, iVal);
+      *piCol = (iVal>=nCol ? nCol-1 : iVal);
+      *piOff = 0;
+      pIter->a += fts5GetVarint32(pIter->a, iVal);
+    }
+    *piOff += (iVal-2);
+  }
+}
+
+static int fts5ApiPhraseFirst(
+  Fts5Context *pCtx,
+  int iPhrase,
+  Fts5PhraseIter *pIter,
+  int *piCol, int *piOff
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int n;
+  int rc = fts5CsrPoslist(pCsr, iPhrase, &pIter->a, &n);
+  if( rc==SQLITE_OK ){
+    assert( pIter->a || n==0 );
+    pIter->b = (pIter->a ? &pIter->a[n] : 0);
+    *piCol = 0;
+    *piOff = 0;
+    fts5ApiPhraseNext(pCtx, pIter, piCol, piOff);
+  }
+  return rc;
+}
+
+static void fts5ApiPhraseNextColumn(
+  Fts5Context *pCtx,
+  Fts5PhraseIter *pIter,
+  int *piCol
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+
+  if( pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+    if( pIter->a>=pIter->b ){
+      *piCol = -1;
+    }else{
+      int iIncr;
+      pIter->a += fts5GetVarint32(&pIter->a[0], iIncr);
+      *piCol += (iIncr-2);
+    }
+  }else{
+    while( 1 ){
+      int dummy;
+      if( pIter->a>=pIter->b ){
+        *piCol = -1;
+        return;
+      }
+      if( pIter->a[0]==0x01 ) break;
+      pIter->a += fts5GetVarint32(pIter->a, dummy);
+    }
+    pIter->a += 1 + fts5GetVarint32(&pIter->a[1], *piCol);
+  }
+}
+
+static int fts5ApiPhraseFirstColumn(
+  Fts5Context *pCtx,
+  int iPhrase,
+  Fts5PhraseIter *pIter,
+  int *piCol
+){
+  int rc = SQLITE_OK;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+
+  if( pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+    Fts5Sorter *pSorter = pCsr->pSorter;
+    int n;
+    if( pSorter ){
+      int i1 = (iPhrase==0 ? 0 : pSorter->aIdx[iPhrase-1]);
+      n = pSorter->aIdx[iPhrase] - i1;
+      pIter->a = &pSorter->aPoslist[i1];
+    }else{
+      rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, iPhrase, &pIter->a, &n);
+    }
+    if( rc==SQLITE_OK ){
+      assert( pIter->a || n==0 );
+      pIter->b = (pIter->a ? &pIter->a[n] : 0);
+      *piCol = 0;
+      fts5ApiPhraseNextColumn(pCtx, pIter, piCol);
+    }
+  }else{
+    int n;
+    rc = fts5CsrPoslist(pCsr, iPhrase, &pIter->a, &n);
+    if( rc==SQLITE_OK ){
+      assert( pIter->a || n==0 );
+      pIter->b = (pIter->a ? &pIter->a[n] : 0);
+      if( n<=0 ){
+        *piCol = -1;
+      }else if( pIter->a[0]==0x01 ){
+        pIter->a += 1 + fts5GetVarint32(&pIter->a[1], *piCol);
+      }else{
+        *piCol = 0;
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** xQueryToken() API implemenetation.
+*/
+static int fts5ApiQueryToken(
+  Fts5Context* pCtx,
+  int iPhrase,
+  int iToken,
+  const char **ppOut,
+  int *pnOut
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return sqlite3Fts5ExprQueryToken(pCsr->pExpr, iPhrase, iToken, ppOut, pnOut);
+}
+
+/*
+** xInstToken() API implemenetation.
+*/
+static int fts5ApiInstToken(
+  Fts5Context *pCtx,
+  int iIdx,
+  int iToken,
+  const char **ppOut, int *pnOut
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int rc = SQLITE_OK;
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_INST)==0
+   || SQLITE_OK==(rc = fts5CacheInstArray(pCsr))
+  ){
+    if( iIdx<0 || iIdx>=pCsr->nInstCount ){
+      rc = SQLITE_RANGE;
+    }else{
+      int iPhrase = pCsr->aInst[iIdx*3];
+      int iCol = pCsr->aInst[iIdx*3 + 1];
+      int iOff = pCsr->aInst[iIdx*3 + 2];
+      i64 iRowid = fts5CursorRowid(pCsr);
+      rc = sqlite3Fts5ExprInstToken(
+          pCsr->pExpr, iRowid, iPhrase, iCol, iOff, iToken, ppOut, pnOut
+      );
+    }
+  }
+  return rc;
+}
+
+
+static int fts5ApiQueryPhrase(Fts5Context*, int, void*,
+    int(*)(const Fts5ExtensionApi*, Fts5Context*, void*)
+);
+
+/*
+** The xColumnLocale() API.
+*/
+static int fts5ApiColumnLocale(
+  Fts5Context *pCtx,
+  int iCol,
+  const char **pzLocale,
+  int *pnLocale
+){
+  int rc = SQLITE_OK;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+
+  *pzLocale = 0;
+  *pnLocale = 0;
+
+  assert( pCsr->ePlan!=FTS5_PLAN_SPECIAL );
+  if( iCol<0 || iCol>=pConfig->nCol ){
+    rc = SQLITE_RANGE;
+  }else if(
+      pConfig->abUnindexed[iCol]==0
+   && 0==fts5IsContentless((Fts5FullTable*)pCsr->base.pVtab, 1)
+   && pConfig->bLocale
+  ){
+    rc = fts5SeekCursor(pCsr, 0);
+    if( rc==SQLITE_OK ){
+      const char *zDummy = 0;
+      int nDummy = 0;
+      rc = fts5TextFromStmt(pConfig, pCsr->pStmt, iCol, &zDummy, &nDummy);
+      if( rc==SQLITE_OK ){
+        *pzLocale = pConfig->t.pLocale;
+        *pnLocale = pConfig->t.nLocale;
+      }
+      sqlite3Fts5ClearLocale(pConfig);
+    }
+  }
+
+  return rc;
+}
+
+static const Fts5ExtensionApi sFts5Api = {
+  4,                            /* iVersion */
+  fts5ApiUserData,
+  fts5ApiColumnCount,
+  fts5ApiRowCount,
+  fts5ApiColumnTotalSize,
+  fts5ApiTokenize,
+  fts5ApiPhraseCount,
+  fts5ApiPhraseSize,
+  fts5ApiInstCount,
+  fts5ApiInst,
+  fts5ApiRowid,
+  fts5ApiColumnText,
+  fts5ApiColumnSize,
+  fts5ApiQueryPhrase,
+  fts5ApiSetAuxdata,
+  fts5ApiGetAuxdata,
+  fts5ApiPhraseFirst,
+  fts5ApiPhraseNext,
+  fts5ApiPhraseFirstColumn,
+  fts5ApiPhraseNextColumn,
+  fts5ApiQueryToken,
+  fts5ApiInstToken,
+  fts5ApiColumnLocale,
+  fts5ApiTokenize_v2
+};
+
+/*
+** Implementation of API function xQueryPhrase().
+*/
+static int fts5ApiQueryPhrase(
+  Fts5Context *pCtx,
+  int iPhrase,
+  void *pUserData,
+  int(*xCallback)(const Fts5ExtensionApi*, Fts5Context*, void*)
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
+  int rc;
+  Fts5Cursor *pNew = 0;
+
+  rc = fts5OpenMethod(pCsr->base.pVtab, (sqlite3_vtab_cursor**)&pNew);
+  if( rc==SQLITE_OK ){
+    pNew->ePlan = FTS5_PLAN_MATCH;
+    pNew->iFirstRowid = SMALLEST_INT64;
+    pNew->iLastRowid = LARGEST_INT64;
+    pNew->base.pVtab = (sqlite3_vtab*)pTab;
+    rc = sqlite3Fts5ExprClonePhrase(pCsr->pExpr, iPhrase, &pNew->pExpr);
+  }
+
+  if( rc==SQLITE_OK ){
+    for(rc = fts5CursorFirst(pTab, pNew, 0);
+        rc==SQLITE_OK && CsrFlagTest(pNew, FTS5CSR_EOF)==0;
+        rc = fts5NextMethod((sqlite3_vtab_cursor*)pNew)
+    ){
+      rc = xCallback(&sFts5Api, (Fts5Context*)pNew, pUserData);
+      if( rc!=SQLITE_OK ){
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+        break;
+      }
+    }
+  }
+
+  fts5CloseMethod((sqlite3_vtab_cursor*)pNew);
+  return rc;
+}
+
+static void fts5ApiInvoke(
+  Fts5Auxiliary *pAux,
+  Fts5Cursor *pCsr,
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( pCsr->pAux==0 );
+  assert( pCsr->ePlan!=FTS5_PLAN_SPECIAL );
+  pCsr->pAux = pAux;
+  pAux->xFunc(&sFts5Api, (Fts5Context*)pCsr, context, argc, argv);
+  pCsr->pAux = 0;
+}
+
+static Fts5Cursor *fts5CursorFromCsrid(Fts5Global *pGlobal, i64 iCsrId){
+  Fts5Cursor *pCsr;
+  for(pCsr=pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
+    if( pCsr->iCsrId==iCsrId ) break;
+  }
+  return pCsr;
+}
+
+/*
+** Parameter zFmt is a printf() style formatting string. This function
+** formats it using the trailing arguments and returns the result as
+** an error message to the context passed as the first argument.
+*/
+static void fts5ResultError(sqlite3_context *pCtx, const char *zFmt, ...){
+  char *zErr = 0;
+  va_list ap;
+  va_start(ap, zFmt);
+  zErr = sqlite3_vmprintf(zFmt, ap);
+  sqlite3_result_error(pCtx, zErr, -1);
+  sqlite3_free(zErr);
+  va_end(ap);
+}
+
+static void fts5ApiCallback(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+
+  Fts5Auxiliary *pAux;
+  Fts5Cursor *pCsr;
+  i64 iCsrId;
+
+  assert( argc>=1 );
+  pAux = (Fts5Auxiliary*)sqlite3_user_data(context);
+  iCsrId = sqlite3_value_int64(argv[0]);
+
+  pCsr = fts5CursorFromCsrid(pAux->pGlobal, iCsrId);
+  if( pCsr==0 || (pCsr->ePlan==0 || pCsr->ePlan==FTS5_PLAN_SPECIAL) ){
+    fts5ResultError(context, "no such cursor: %lld", iCsrId);
+  }else{
+    sqlite3_vtab *pTab = pCsr->base.pVtab;
+    fts5ApiInvoke(pAux, pCsr, context, argc-1, &argv[1]);
+    sqlite3_free(pTab->zErrMsg);
+    pTab->zErrMsg = 0;
+  }
+}
+
+
+/*
+** Given cursor id iId, return a pointer to the corresponding Fts5Table
+** object. Or NULL If the cursor id does not exist.
+*/
+static Fts5Table *sqlite3Fts5TableFromCsrid(
+  Fts5Global *pGlobal,            /* FTS5 global context for db handle */
+  i64 iCsrId                      /* Id of cursor to find */
+){
+  Fts5Cursor *pCsr;
+  pCsr = fts5CursorFromCsrid(pGlobal, iCsrId);
+  if( pCsr ){
+    return (Fts5Table*)pCsr->base.pVtab;
+  }
+  return 0;
+}
+
+/*
+** Return a "position-list blob" corresponding to the current position of
+** cursor pCsr via sqlite3_result_blob(). A position-list blob contains
+** the current position-list for each phrase in the query associated with
+** cursor pCsr.
+**
+** A position-list blob begins with (nPhrase-1) varints, where nPhrase is
+** the number of phrases in the query. Following the varints are the
+** concatenated position lists for each phrase, in order.
+**
+** The first varint (if it exists) contains the size of the position list
+** for phrase 0. The second (same disclaimer) contains the size of position
+** list 1. And so on. There is no size field for the final position list,
+** as it can be derived from the total size of the blob.
+*/
+static int fts5PoslistBlob(sqlite3_context *pCtx, Fts5Cursor *pCsr){
+  int i;
+  int rc = SQLITE_OK;
+  int nPhrase = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+  Fts5Buffer val;
+
+  memset(&val, 0, sizeof(Fts5Buffer));
+  switch( ((Fts5Table*)(pCsr->base.pVtab))->pConfig->eDetail ){
+    case FTS5_DETAIL_FULL:
+
+      /* Append the varints */
+      for(i=0; i<(nPhrase-1); i++){
+        const u8 *dummy;
+        int nByte = sqlite3Fts5ExprPoslist(pCsr->pExpr, i, &dummy);
+        sqlite3Fts5BufferAppendVarint(&rc, &val, nByte);
+      }
+
+      /* Append the position lists */
+      for(i=0; i<nPhrase; i++){
+        const u8 *pPoslist;
+        int nPoslist;
+        nPoslist = sqlite3Fts5ExprPoslist(pCsr->pExpr, i, &pPoslist);
+        sqlite3Fts5BufferAppendBlob(&rc, &val, nPoslist, pPoslist);
+      }
+      break;
+
+    case FTS5_DETAIL_COLUMNS:
+
+      /* Append the varints */
+      for(i=0; rc==SQLITE_OK && i<(nPhrase-1); i++){
+        const u8 *dummy;
+        int nByte;
+        rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, i, &dummy, &nByte);
+        sqlite3Fts5BufferAppendVarint(&rc, &val, nByte);
+      }
+
+      /* Append the position lists */
+      for(i=0; rc==SQLITE_OK && i<nPhrase; i++){
+        const u8 *pPoslist;
+        int nPoslist;
+        rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, i, &pPoslist, &nPoslist);
+        sqlite3Fts5BufferAppendBlob(&rc, &val, nPoslist, pPoslist);
+      }
+      break;
+
+    default:
+      break;
+  }
+
+  sqlite3_result_blob(pCtx, val.p, val.n, sqlite3_free);
+  return rc;
+}
+
+/*
+** This is the xColumn method, called by SQLite to request a value from
+** the row that the supplied cursor currently points to.
+*/
+static int fts5ColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)(pCursor->pVtab);
+  Fts5Config *pConfig = pTab->p.pConfig;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int rc = SQLITE_OK;
+
+  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );
+
+  if( pCsr->ePlan==FTS5_PLAN_SPECIAL ){
+    if( iCol==pConfig->nCol ){
+      sqlite3_result_int64(pCtx, pCsr->iSpecial);
+    }
+  }else
+
+  if( iCol==pConfig->nCol ){
+    /* User is requesting the value of the special column with the same name
+    ** as the table. Return the cursor integer id number. This value is only
+    ** useful in that it may be passed as the first argument to an FTS5
+    ** auxiliary function.  */
+    sqlite3_result_int64(pCtx, pCsr->iCsrId);
+  }else if( iCol==pConfig->nCol+1 ){
+    /* The value of the "rank" column. */
+
+    if( pCsr->ePlan==FTS5_PLAN_SOURCE ){
+      fts5PoslistBlob(pCtx, pCsr);
+    }else if(
+        pCsr->ePlan==FTS5_PLAN_MATCH
+     || pCsr->ePlan==FTS5_PLAN_SORTED_MATCH
+    ){
+      if( pCsr->pRank || SQLITE_OK==(rc = fts5FindRankFunction(pCsr)) ){
+        fts5ApiInvoke(pCsr->pRank, pCsr, pCtx, pCsr->nRankArg, pCsr->apRankArg);
+      }
+    }
+  }else{
+    if( !sqlite3_vtab_nochange(pCtx) && pConfig->eContent!=FTS5_CONTENT_NONE ){
+      pConfig->pzErrmsg = &pTab->p.base.zErrMsg;
+      rc = fts5SeekCursor(pCsr, 1);
+      if( rc==SQLITE_OK ){
+        sqlite3_value *pVal = sqlite3_column_value(pCsr->pStmt, iCol+1);
+        if( pConfig->bLocale
+         && pConfig->eContent==FTS5_CONTENT_EXTERNAL
+         && sqlite3Fts5IsLocaleValue(pConfig, pVal)
+        ){
+          const char *z = 0;
+          int n = 0;
+          rc = fts5TextFromStmt(pConfig, pCsr->pStmt, iCol, &z, &n);
+          if( rc==SQLITE_OK ){
+            sqlite3_result_text(pCtx, z, n, SQLITE_TRANSIENT);
+          }
+          sqlite3Fts5ClearLocale(pConfig);
+        }else{
+          sqlite3_result_value(pCtx, pVal);
+        }
+      }
+
+      pConfig->pzErrmsg = 0;
+    }
+  }
+
+  return rc;
+}
+
+
+/*
+** This routine implements the xFindFunction method for the FTS3
+** virtual table.
+*/
+static int fts5FindFunctionMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nUnused,                    /* Number of SQL function arguments */
+  const char *zName,              /* Name of SQL function */
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
+  void **ppArg                    /* OUT: User data for *pxFunc */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  Fts5Auxiliary *pAux;
+
+  UNUSED_PARAM(nUnused);
+  pAux = fts5FindAuxiliary(pTab, zName);
+  if( pAux ){
+    *pxFunc = fts5ApiCallback;
+    *ppArg = (void*)pAux;
+    return 1;
+  }
+
+  /* No function of the specified name was found. Return 0. */
+  return 0;
+}
+
+/*
+** Implementation of FTS5 xRename method. Rename an fts5 table.
+*/
+static int fts5RenameMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  const char *zName               /* New name of table */
+){
+  int rc;
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  rc = sqlite3Fts5StorageRename(pTab->pStorage, zName);
+  return rc;
+}
+
+static int sqlite3Fts5FlushToDisk(Fts5Table *pTab){
+  fts5TripCursors((Fts5FullTable*)pTab);
+  return sqlite3Fts5StorageSync(((Fts5FullTable*)pTab)->pStorage);
+}
+
+/*
+** The xSavepoint() method.
+**
+** Flush the contents of the pending-terms table to disk.
+*/
+static int fts5SavepointMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  int rc = SQLITE_OK;
+
+  fts5CheckTransactionState(pTab, FTS5_SAVEPOINT, iSavepoint);
+  rc = sqlite3Fts5FlushToDisk((Fts5Table*)pVtab);
+  if( rc==SQLITE_OK ){
+    pTab->iSavepoint = iSavepoint+1;
+  }
+  return rc;
+}
+
+/*
+** The xRelease() method.
+**
+** This is a no-op.
+*/
+static int fts5ReleaseMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  int rc = SQLITE_OK;
+  fts5CheckTransactionState(pTab, FTS5_RELEASE, iSavepoint);
+  if( (iSavepoint+1)<pTab->iSavepoint ){
+    rc = sqlite3Fts5FlushToDisk(&pTab->p);
+    if( rc==SQLITE_OK ){
+      pTab->iSavepoint = iSavepoint;
+    }
+  }
+  return rc;
+}
+
+/*
+** The xRollbackTo() method.
+**
+** Discard the contents of the pending terms table.
+*/
+static int fts5RollbackToMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  int rc = SQLITE_OK;
+  fts5CheckTransactionState(pTab, FTS5_ROLLBACKTO, iSavepoint);
+  fts5TripCursors(pTab);
+  if( (iSavepoint+1)<=pTab->iSavepoint ){
+    pTab->p.pConfig->pgsz = 0;
+    rc = sqlite3Fts5StorageRollback(pTab->pStorage);
+  }
+  return rc;
+}
+
+/*
+** Register a new auxiliary function with global context pGlobal.
+*/
+static int fts5CreateAux(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  fts5_extension_function xFunc,  /* Aux. function implementation */
+  void(*xDestroy)(void*)          /* Destructor for pUserData */
+){
+  Fts5Global *pGlobal = (Fts5Global*)pApi;
+  int rc = sqlite3_overload_function(pGlobal->db, zName, -1);
+  if( rc==SQLITE_OK ){
+    Fts5Auxiliary *pAux;
+    sqlite3_int64 nName;            /* Size of zName in bytes, including \0 */
+    sqlite3_int64 nByte;            /* Bytes of space to allocate */
+
+    nName = strlen(zName) + 1;
+    nByte = sizeof(Fts5Auxiliary) + nName;
+    pAux = (Fts5Auxiliary*)sqlite3_malloc64(nByte);
+    if( pAux ){
+      memset(pAux, 0, (size_t)nByte);
+      pAux->zFunc = (char*)&pAux[1];
+      memcpy(pAux->zFunc, zName, nName);
+      pAux->pGlobal = pGlobal;
+      pAux->pUserData = pUserData;
+      pAux->xFunc = xFunc;
+      pAux->xDestroy = xDestroy;
+      pAux->pNext = pGlobal->pAux;
+      pGlobal->pAux = pAux;
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function is used by xCreateTokenizer_v2() and xCreateTokenizer().
+** It allocates and partially populates a new Fts5TokenizerModule object.
+** The new object is already linked into the Fts5Global context before
+** returning.
+**
+** If successful, SQLITE_OK is returned and a pointer to the new
+** Fts5TokenizerModule object returned via output parameter (*ppNew). All
+** that is required is for the caller to fill in the methods in
+** Fts5TokenizerModule.x1 and x2, and to set Fts5TokenizerModule.bV2Native
+** as appropriate.
+**
+** If an error occurs, an SQLite error code is returned and the final value
+** of (*ppNew) undefined.
+*/
+static int fts5NewTokenizerModule(
+  Fts5Global *pGlobal,            /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  void(*xDestroy)(void*),         /* Destructor for pUserData */
+  Fts5TokenizerModule **ppNew
+){
+  int rc = SQLITE_OK;
+  Fts5TokenizerModule *pNew;
+  sqlite3_int64 nName;          /* Size of zName and its \0 terminator */
+  sqlite3_int64 nByte;          /* Bytes of space to allocate */
+
+  nName = strlen(zName) + 1;
+  nByte = sizeof(Fts5TokenizerModule) + nName;
+  *ppNew = pNew = (Fts5TokenizerModule*)sqlite3Fts5MallocZero(&rc, nByte);
+  if( pNew ){
+    pNew->zName = (char*)&pNew[1];
+    memcpy(pNew->zName, zName, nName);
+    pNew->pUserData = pUserData;
+    pNew->xDestroy = xDestroy;
+    pNew->pNext = pGlobal->pTok;
+    pGlobal->pTok = pNew;
+    if( pNew->pNext==0 ){
+      pGlobal->pDfltTok = pNew;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** An instance of this type is used as the Fts5Tokenizer object for
+** wrapper tokenizers - those that provide access to a v1 tokenizer via
+** the fts5_tokenizer_v2 API, and those that provide access to a v2 tokenizer
+** via the fts5_tokenizer API.
+*/
+typedef struct Fts5VtoVTokenizer Fts5VtoVTokenizer;
+struct Fts5VtoVTokenizer {
+  int bV2Native;                  /* True if v2 native tokenizer */
+  fts5_tokenizer x1;              /* Tokenizer functions */
+  fts5_tokenizer_v2 x2;           /* V2 tokenizer functions */
+  Fts5Tokenizer *pReal;
+};
+
+/*
+** Create a wrapper tokenizer. The context argument pCtx points to the
+** Fts5TokenizerModule object.
+*/
+static int fts5VtoVCreate(
+  void *pCtx,
+  const char **azArg,
+  int nArg,
+  Fts5Tokenizer **ppOut
+){
+  Fts5TokenizerModule *pMod = (Fts5TokenizerModule*)pCtx;
+  Fts5VtoVTokenizer *pNew = 0;
+  int rc = SQLITE_OK;
+
+  pNew = (Fts5VtoVTokenizer*)sqlite3Fts5MallocZero(&rc, sizeof(*pNew));
+  if( rc==SQLITE_OK ){
+    pNew->x1 = pMod->x1;
+    pNew->x2 = pMod->x2;
+    pNew->bV2Native = pMod->bV2Native;
+    if( pMod->bV2Native ){
+      rc = pMod->x2.xCreate(pMod->pUserData, azArg, nArg, &pNew->pReal);
+    }else{
+      rc = pMod->x1.xCreate(pMod->pUserData, azArg, nArg, &pNew->pReal);
+    }
+    if( rc!=SQLITE_OK ){
+      sqlite3_free(pNew);
+      pNew = 0;
+    }
+  }
+
+  *ppOut = (Fts5Tokenizer*)pNew;
+  return rc;
+}
+
+/*
+** Delete an Fts5VtoVTokenizer wrapper tokenizer.
+*/
+static void fts5VtoVDelete(Fts5Tokenizer *pTok){
+  Fts5VtoVTokenizer *p = (Fts5VtoVTokenizer*)pTok;
+  if( p ){
+    if( p->bV2Native ){
+      p->x2.xDelete(p->pReal);
+    }else{
+      p->x1.xDelete(p->pReal);
+    }
+    sqlite3_free(p);
+  }
+}
+
+
+/*
+** xTokenizer method for a wrapper tokenizer that offers the v1 interface
+** (no support for locales).
+*/
+static int fts5V1toV2Tokenize(
+  Fts5Tokenizer *pTok,
+  void *pCtx, int flags,
+  const char *pText, int nText,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  Fts5VtoVTokenizer *p = (Fts5VtoVTokenizer*)pTok;
+  assert( p->bV2Native );
+  return p->x2.xTokenize(p->pReal, pCtx, flags, pText, nText, 0, 0, xToken);
+}
+
+/*
+** xTokenizer method for a wrapper tokenizer that offers the v2 interface
+** (with locale support).
+*/
+static int fts5V2toV1Tokenize(
+  Fts5Tokenizer *pTok,
+  void *pCtx, int flags,
+  const char *pText, int nText,
+  const char *pLocale, int nLocale,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  Fts5VtoVTokenizer *p = (Fts5VtoVTokenizer*)pTok;
+  assert( p->bV2Native==0 );
+  UNUSED_PARAM2(pLocale,nLocale);
+  return p->x1.xTokenize(p->pReal, pCtx, flags, pText, nText, xToken);
+}
+
+/*
+** Register a new tokenizer. This is the implementation of the
+** fts5_api.xCreateTokenizer_v2() method.
+*/
+static int fts5CreateTokenizer_v2(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  fts5_tokenizer_v2 *pTokenizer,  /* Tokenizer implementation */
+  void(*xDestroy)(void*)          /* Destructor for pUserData */
+){
+  Fts5Global *pGlobal = (Fts5Global*)pApi;
+  int rc = SQLITE_OK;
+
+  if( pTokenizer->iVersion>2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    Fts5TokenizerModule *pNew = 0;
+    rc = fts5NewTokenizerModule(pGlobal, zName, pUserData, xDestroy, &pNew);
+    if( pNew ){
+      pNew->x2 = *pTokenizer;
+      pNew->bV2Native = 1;
+      pNew->x1.xCreate = fts5VtoVCreate;
+      pNew->x1.xTokenize = fts5V1toV2Tokenize;
+      pNew->x1.xDelete = fts5VtoVDelete;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** The fts5_api.xCreateTokenizer() method.
+*/
+static int fts5CreateTokenizer(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  fts5_tokenizer *pTokenizer,     /* Tokenizer implementation */
+  void(*xDestroy)(void*)          /* Destructor for pUserData */
+){
+  Fts5TokenizerModule *pNew = 0;
+  int rc = SQLITE_OK;
+
+  rc = fts5NewTokenizerModule(
+      (Fts5Global*)pApi, zName, pUserData, xDestroy, &pNew
+  );
+  if( pNew ){
+    pNew->x1 = *pTokenizer;
+    pNew->x2.xCreate = fts5VtoVCreate;
+    pNew->x2.xTokenize = fts5V2toV1Tokenize;
+    pNew->x2.xDelete = fts5VtoVDelete;
+  }
+  return rc;
+}
+
+/*
+** Search the global context passed as the first argument for a tokenizer
+** module named zName. If found, return a pointer to the Fts5TokenizerModule
+** object. Otherwise, return NULL.
+*/
+static Fts5TokenizerModule *fts5LocateTokenizer(
+  Fts5Global *pGlobal,            /* Global (one per db handle) object */
+  const char *zName               /* Name of tokenizer module to find */
+){
+  Fts5TokenizerModule *pMod = 0;
+
+  if( zName==0 ){
+    pMod = pGlobal->pDfltTok;
+  }else{
+    for(pMod=pGlobal->pTok; pMod; pMod=pMod->pNext){
+      if( sqlite3_stricmp(zName, pMod->zName)==0 ) break;
+    }
+  }
+
+  return pMod;
+}
+
+/*
+** Find a tokenizer. This is the implementation of the
+** fts5_api.xFindTokenizer_v2() method.
+*/
+static int fts5FindTokenizer_v2(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of tokenizer */
+  void **ppUserData,
+  fts5_tokenizer_v2 **ppTokenizer /* Populate this object */
+){
+  int rc = SQLITE_OK;
+  Fts5TokenizerModule *pMod;
+
+  pMod = fts5LocateTokenizer((Fts5Global*)pApi, zName);
+  if( pMod ){
+    if( pMod->bV2Native ){
+      *ppUserData = pMod->pUserData;
+    }else{
+      *ppUserData = (void*)pMod;
+    }
+    *ppTokenizer = &pMod->x2;
+  }else{
+    *ppTokenizer = 0;
+    *ppUserData = 0;
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+/*
+** Find a tokenizer. This is the implementation of the
+** fts5_api.xFindTokenizer() method.
+*/
+static int fts5FindTokenizer(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void **ppUserData,
+  fts5_tokenizer *pTokenizer      /* Populate this object */
+){
+  int rc = SQLITE_OK;
+  Fts5TokenizerModule *pMod;
+
+  pMod = fts5LocateTokenizer((Fts5Global*)pApi, zName);
+  if( pMod ){
+    if( pMod->bV2Native==0 ){
+      *ppUserData = pMod->pUserData;
+    }else{
+      *ppUserData = (void*)pMod;
+    }
+    *pTokenizer = pMod->x1;
+  }else{
+    memset(pTokenizer, 0, sizeof(*pTokenizer));
+    *ppUserData = 0;
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+/*
+** Attempt to instantiate the tokenizer.
+*/
+static int sqlite3Fts5LoadTokenizer(Fts5Config *pConfig){
+  const char **azArg = pConfig->t.azArg;
+  const int nArg = pConfig->t.nArg;
+  Fts5TokenizerModule *pMod = 0;
+  int rc = SQLITE_OK;
+
+  pMod = fts5LocateTokenizer(pConfig->pGlobal, nArg==0 ? 0 : azArg[0]);
+  if( pMod==0 ){
+    assert( nArg>0 );
+    rc = SQLITE_ERROR;
+    sqlite3Fts5ConfigErrmsg(pConfig, "no such tokenizer: %s", azArg[0]);
+  }else{
+    int (*xCreate)(void*, const char**, int, Fts5Tokenizer**) = 0;
+    if( pMod->bV2Native ){
+      xCreate = pMod->x2.xCreate;
+      pConfig->t.pApi2 = &pMod->x2;
+    }else{
+      pConfig->t.pApi1 = &pMod->x1;
+      xCreate = pMod->x1.xCreate;
+    }
+
+    rc = xCreate(pMod->pUserData,
+        (azArg?&azArg[1]:0), (nArg?nArg-1:0), &pConfig->t.pTok
+    );
+
+    if( rc!=SQLITE_OK ){
+      if( rc!=SQLITE_NOMEM ){
+        sqlite3Fts5ConfigErrmsg(pConfig, "error in tokenizer constructor");
+      }
+    }else if( pMod->bV2Native==0 ){
+      pConfig->t.ePattern = sqlite3Fts5TokenizerPattern(
+          pMod->x1.xCreate, pConfig->t.pTok
+      );
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    pConfig->t.pApi1 = 0;
+    pConfig->t.pApi2 = 0;
+    pConfig->t.pTok = 0;
+  }
+
+  return rc;
+}
+
+
+/*
+** xDestroy callback passed to sqlite3_create_module(). This is invoked
+** when the db handle is being closed. Free memory associated with
+** tokenizers and aux functions registered with this db handle.
+*/
+static void fts5ModuleDestroy(void *pCtx){
+  Fts5TokenizerModule *pTok, *pNextTok;
+  Fts5Auxiliary *pAux, *pNextAux;
+  Fts5Global *pGlobal = (Fts5Global*)pCtx;
+
+  for(pAux=pGlobal->pAux; pAux; pAux=pNextAux){
+    pNextAux = pAux->pNext;
+    if( pAux->xDestroy ) pAux->xDestroy(pAux->pUserData);
+    sqlite3_free(pAux);
+  }
+
+  for(pTok=pGlobal->pTok; pTok; pTok=pNextTok){
+    pNextTok = pTok->pNext;
+    if( pTok->xDestroy ) pTok->xDestroy(pTok->pUserData);
+    sqlite3_free(pTok);
+  }
+
+  sqlite3_free(pGlobal);
+}
+
+/*
+** Implementation of the fts5() function used by clients to obtain the
+** API pointer.
+*/
+static void fts5Fts5Func(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apArg           /* Function arguments */
+){
+  Fts5Global *pGlobal = (Fts5Global*)sqlite3_user_data(pCtx);
+  fts5_api **ppApi;
+  UNUSED_PARAM(nArg);
+  assert( nArg==1 );
+  ppApi = (fts5_api**)sqlite3_value_pointer(apArg[0], "fts5_api_ptr");
+  if( ppApi ) *ppApi = &pGlobal->api;
+}
+
+/*
+** Implementation of fts5_source_id() function.
+*/
+static void fts5SourceIdFunc(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apUnused        /* Function arguments */
+){
+  assert( nArg==0 );
+  UNUSED_PARAM2(nArg, apUnused);
+  sqlite3_result_text(pCtx, "fts5: 2025-05-07 10:39:52 17144570b0d96ae63cd6f3edca39e27ebd74925252bbaf6723bcb2f6b4861fb1", -1, SQLITE_TRANSIENT);
+}
+
+/*
+** Implementation of fts5_locale(LOCALE, TEXT) function.
+**
+** If parameter LOCALE is NULL, or a zero-length string, then a copy of
+** TEXT is returned. Otherwise, both LOCALE and TEXT are interpreted as
+** text, and the value returned is a blob consisting of:
+**
+**     * The 4 bytes 0x00, 0xE0, 0xB2, 0xEb (FTS5_LOCALE_HEADER).
+**     * The LOCALE, as utf-8 text, followed by
+**     * 0x00, followed by
+**     * The TEXT, as utf-8 text.
+**
+** There is no final nul-terminator following the TEXT value.
+*/
+static void fts5LocaleFunc(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apArg           /* Function arguments */
+){
+  const char *zLocale = 0;
+  int nLocale = 0;
+  const char *zText = 0;
+  int nText = 0;
+
+  assert( nArg==2 );
+  UNUSED_PARAM(nArg);
+
+  zLocale = (const char*)sqlite3_value_text(apArg[0]);
+  nLocale = sqlite3_value_bytes(apArg[0]);
+
+  zText = (const char*)sqlite3_value_text(apArg[1]);
+  nText = sqlite3_value_bytes(apArg[1]);
+
+  if( zLocale==0 || zLocale[0]=='\0' ){
+    sqlite3_result_text(pCtx, zText, nText, SQLITE_TRANSIENT);
+  }else{
+    Fts5Global *p = (Fts5Global*)sqlite3_user_data(pCtx);
+    u8 *pBlob = 0;
+    u8 *pCsr = 0;
+    int nBlob = 0;
+
+    nBlob = FTS5_LOCALE_HDR_SIZE + nLocale + 1 + nText;
+    pBlob = (u8*)sqlite3_malloc(nBlob);
+    if( pBlob==0 ){
+      sqlite3_result_error_nomem(pCtx);
+      return;
+    }
+
+    pCsr = pBlob;
+    memcpy(pCsr, (const u8*)p->aLocaleHdr, FTS5_LOCALE_HDR_SIZE);
+    pCsr += FTS5_LOCALE_HDR_SIZE;
+    memcpy(pCsr, zLocale, nLocale);
+    pCsr += nLocale;
+    (*pCsr++) = 0x00;
+    if( zText ) memcpy(pCsr, zText, nText);
+    assert( &pCsr[nText]==&pBlob[nBlob] );
+
+    sqlite3_result_blob(pCtx, pBlob, nBlob, sqlite3_free);
+  }
+}
+
+/*
+** Implementation of fts5_insttoken() function.
+*/
+static void fts5InsttokenFunc(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apArg           /* Function arguments */
+){
+  assert( nArg==1 );
+  (void)nArg;
+  sqlite3_result_value(pCtx, apArg[0]);
+  sqlite3_result_subtype(pCtx, FTS5_INSTTOKEN_SUBTYPE);
+}
+
+/*
+** Return true if zName is the extension on one of the shadow tables used
+** by this module.
+*/
+static int fts5ShadowName(const char *zName){
+  static const char *azName[] = {
+    "config", "content", "data", "docsize", "idx"
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
+    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
+  }
+  return 0;
+}
+
+/*
+** Run an integrity check on the FTS5 data structures.  Return a string
+** if anything is found amiss.  Return a NULL pointer if everything is
+** OK.
+*/
+static int fts5IntegrityMethod(
+  sqlite3_vtab *pVtab,    /* the FTS5 virtual table to check */
+  const char *zSchema,    /* Name of schema in which this table lives */
+  const char *zTabname,   /* Name of the table itself */
+  int isQuick,            /* True if this is a quick-check */
+  char **pzErr            /* Write error message here */
+){
+  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
+  int rc;
+
+  assert( pzErr!=0 && *pzErr==0 );
+  UNUSED_PARAM(isQuick);
+  assert( pTab->p.pConfig->pzErrmsg==0 );
+  pTab->p.pConfig->pzErrmsg = pzErr;
+  rc = sqlite3Fts5StorageIntegrity(pTab->pStorage, 0);
+  if( *pzErr==0 && rc!=SQLITE_OK ){
+    if( (rc&0xff)==SQLITE_CORRUPT ){
+      *pzErr = sqlite3_mprintf("malformed inverted index for FTS5 table %s.%s",
+          zSchema, zTabname);
+      rc = (*pzErr) ? SQLITE_OK : SQLITE_NOMEM;
+    }else{
+      *pzErr = sqlite3_mprintf("unable to validate the inverted index for"
+          " FTS5 table %s.%s: %s",
+          zSchema, zTabname, sqlite3_errstr(rc));
+    }
+  }
+
+  sqlite3Fts5IndexCloseReader(pTab->p.pIndex);
+  pTab->p.pConfig->pzErrmsg = 0;
+
+  return rc;
+}
+
+static int fts5Init(sqlite3 *db){
+  static const sqlite3_module fts5Mod = {
+    /* iVersion      */ 4,
+    /* xCreate       */ fts5CreateMethod,
+    /* xConnect      */ fts5ConnectMethod,
+    /* xBestIndex    */ fts5BestIndexMethod,
+    /* xDisconnect   */ fts5DisconnectMethod,
+    /* xDestroy      */ fts5DestroyMethod,
+    /* xOpen         */ fts5OpenMethod,
+    /* xClose        */ fts5CloseMethod,
+    /* xFilter       */ fts5FilterMethod,
+    /* xNext         */ fts5NextMethod,
+    /* xEof          */ fts5EofMethod,
+    /* xColumn       */ fts5ColumnMethod,
+    /* xRowid        */ fts5RowidMethod,
+    /* xUpdate       */ fts5UpdateMethod,
+    /* xBegin        */ fts5BeginMethod,
+    /* xSync         */ fts5SyncMethod,
+    /* xCommit       */ fts5CommitMethod,
+    /* xRollback     */ fts5RollbackMethod,
+    /* xFindFunction */ fts5FindFunctionMethod,
+    /* xRename       */ fts5RenameMethod,
+    /* xSavepoint    */ fts5SavepointMethod,
+    /* xRelease      */ fts5ReleaseMethod,
+    /* xRollbackTo   */ fts5RollbackToMethod,
+    /* xShadowName   */ fts5ShadowName,
+    /* xIntegrity    */ fts5IntegrityMethod
+  };
+
+  int rc;
+  Fts5Global *pGlobal = 0;
+
+  pGlobal = (Fts5Global*)sqlite3_malloc(sizeof(Fts5Global));
+  if( pGlobal==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    void *p = (void*)pGlobal;
+    memset(pGlobal, 0, sizeof(Fts5Global));
+    pGlobal->db = db;
+    pGlobal->api.iVersion = 3;
+    pGlobal->api.xCreateFunction = fts5CreateAux;
+    pGlobal->api.xCreateTokenizer = fts5CreateTokenizer;
+    pGlobal->api.xFindTokenizer = fts5FindTokenizer;
+    pGlobal->api.xCreateTokenizer_v2 = fts5CreateTokenizer_v2;
+    pGlobal->api.xFindTokenizer_v2 = fts5FindTokenizer_v2;
+
+    /* Initialize pGlobal->aLocaleHdr[] to a 128-bit pseudo-random vector.
+    ** The constants below were generated randomly.  */
+    sqlite3_randomness(sizeof(pGlobal->aLocaleHdr), pGlobal->aLocaleHdr);
+    pGlobal->aLocaleHdr[0] ^= 0xF924976D;
+    pGlobal->aLocaleHdr[1] ^= 0x16596E13;
+    pGlobal->aLocaleHdr[2] ^= 0x7C80BEAA;
+    pGlobal->aLocaleHdr[3] ^= 0x9B03A67F;
+    assert( sizeof(pGlobal->aLocaleHdr)==16 );
+
+    rc = sqlite3_create_module_v2(db, "fts5", &fts5Mod, p, fts5ModuleDestroy);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5IndexInit(db);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5ExprInit(pGlobal, db);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5AuxInit(&pGlobal->api);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5TokenizerInit(&pGlobal->api);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5VocabInit(pGlobal, db);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5", 1, SQLITE_UTF8, p, fts5Fts5Func, 0, 0
+      );
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5_source_id", 0,
+          SQLITE_UTF8|SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS,
+          p, fts5SourceIdFunc, 0, 0
+      );
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5_locale", 2,
+          SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_RESULT_SUBTYPE|SQLITE_SUBTYPE,
+          p, fts5LocaleFunc, 0, 0
+      );
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5_insttoken", 1,
+          SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_RESULT_SUBTYPE,
+          p, fts5InsttokenFunc, 0, 0
+      );
+    }
+  }
+
+  /* If SQLITE_FTS5_ENABLE_TEST_MI is defined, assume that the file
+  ** fts5_test_mi.c is compiled and linked into the executable. And call
+  ** its entry point to enable the matchinfo() demo.  */
+#ifdef SQLITE_FTS5_ENABLE_TEST_MI
+  if( rc==SQLITE_OK ){
+    extern int sqlite3Fts5TestRegisterMatchinfo(sqlite3*);
+    rc = sqlite3Fts5TestRegisterMatchinfo(db);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** The following functions are used to register the module with SQLite. If
+** this module is being built as part of the SQLite core (SQLITE_CORE is
+** defined), then sqlite3_open() will call sqlite3Fts5Init() directly.
+**
+** Or, if this module is being built as a loadable extension,
+** sqlite3Fts5Init() is omitted and the two standard entry points
+** sqlite3_fts_init() and sqlite3_fts5_init() defined instead.
+*/
+#ifndef SQLITE_CORE
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_fts_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi);
+  (void)pzErrMsg;  /* Unused parameter */
+  return fts5Init(db);
+}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_fts5_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi);
+  (void)pzErrMsg;  /* Unused parameter */
+  return fts5Init(db);
+}
+#else
+SQLITE_PRIVATE int sqlite3Fts5Init(sqlite3 *db){
+  return fts5Init(db);
+}
+#endif
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+
+
+
+/* #include "fts5Int.h" */
+
+/*
+** pSavedRow:
+**   SQL statement FTS5_STMT_LOOKUP2 is a copy of FTS5_STMT_LOOKUP, it
+**   does a by-rowid lookup to retrieve a single row from the %_content
+**   table or equivalent external-content table/view.
+**
+**   However, FTS5_STMT_LOOKUP2 is only used when retrieving the original
+**   values for a row being UPDATEd. In that case, the SQL statement is
+**   not reset and pSavedRow is set to point at it. This is so that the
+**   insert operation that follows the delete may access the original
+**   row values for any new values for which sqlite3_value_nochange() returns
+**   true. i.e. if the user executes:
+**
+**        CREATE VIRTUAL TABLE ft USING fts5(a, b, c, locale=1);
+**        ...
+**        UPDATE fts SET a=?, b=? WHERE rowid=?;
+**
+**   then the value passed to the xUpdate() method of this table as the
+**   new.c value is an sqlite3_value_nochange() value. So in this case it
+**   must be read from the saved row stored in Fts5Storage.pSavedRow.
+**
+**   This is necessary - using sqlite3_value_nochange() instead of just having
+**   SQLite pass the original value back via xUpdate() - so as not to discard
+**   any locale information associated with such values.
+**
+*/
+struct Fts5Storage {
+  Fts5Config *pConfig;
+  Fts5Index *pIndex;
+  int bTotalsValid;               /* True if nTotalRow/aTotalSize[] are valid */
+  i64 nTotalRow;                  /* Total number of rows in FTS table */
+  i64 *aTotalSize;                /* Total sizes of each column */
+  sqlite3_stmt *pSavedRow;
+  sqlite3_stmt *aStmt[12];
+};
+
+
+#if FTS5_STMT_SCAN_ASC!=0
+# error "FTS5_STMT_SCAN_ASC mismatch"
+#endif
+#if FTS5_STMT_SCAN_DESC!=1
+# error "FTS5_STMT_SCAN_DESC mismatch"
+#endif
+#if FTS5_STMT_LOOKUP!=2
+# error "FTS5_STMT_LOOKUP mismatch"
+#endif
+
+#define FTS5_STMT_LOOKUP2         3
+#define FTS5_STMT_INSERT_CONTENT  4
+#define FTS5_STMT_REPLACE_CONTENT 5
+#define FTS5_STMT_DELETE_CONTENT  6
+#define FTS5_STMT_REPLACE_DOCSIZE 7
+#define FTS5_STMT_DELETE_DOCSIZE  8
+#define FTS5_STMT_LOOKUP_DOCSIZE  9
+#define FTS5_STMT_REPLACE_CONFIG 10
+#define FTS5_STMT_SCAN           11
+
+/*
+** Prepare the two insert statements - Fts5Storage.pInsertContent and
+** Fts5Storage.pInsertDocsize - if they have not already been prepared.
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int fts5StorageGetStmt(
+  Fts5Storage *p,                 /* Storage handle */
+  int eStmt,                      /* FTS5_STMT_XXX constant */
+  sqlite3_stmt **ppStmt,          /* OUT: Prepared statement handle */
+  char **pzErrMsg                 /* OUT: Error message (if any) */
+){
+  int rc = SQLITE_OK;
+
+  /* If there is no %_docsize table, there should be no requests for
+  ** statements to operate on it.  */
+  assert( p->pConfig->bColumnsize || (
+        eStmt!=FTS5_STMT_REPLACE_DOCSIZE
+     && eStmt!=FTS5_STMT_DELETE_DOCSIZE
+     && eStmt!=FTS5_STMT_LOOKUP_DOCSIZE
+  ));
+
+  assert( eStmt>=0 && eStmt<ArraySize(p->aStmt) );
+  if( p->aStmt[eStmt]==0 ){
+    const char *azStmt[] = {
+      "SELECT %s FROM %s T WHERE T.%Q >= ? AND T.%Q <= ? ORDER BY T.%Q ASC",
+      "SELECT %s FROM %s T WHERE T.%Q <= ? AND T.%Q >= ? ORDER BY T.%Q DESC",
+      "SELECT %s FROM %s T WHERE T.%Q=?",               /* LOOKUP  */
+      "SELECT %s FROM %s T WHERE T.%Q=?",               /* LOOKUP2  */
+
+      "INSERT INTO %Q.'%q_content' VALUES(%s)",         /* INSERT_CONTENT  */
+      "REPLACE INTO %Q.'%q_content' VALUES(%s)",        /* REPLACE_CONTENT */
+      "DELETE FROM %Q.'%q_content' WHERE id=?",         /* DELETE_CONTENT  */
+      "REPLACE INTO %Q.'%q_docsize' VALUES(?,?%s)",     /* REPLACE_DOCSIZE  */
+      "DELETE FROM %Q.'%q_docsize' WHERE id=?",         /* DELETE_DOCSIZE  */
+
+      "SELECT sz%s FROM %Q.'%q_docsize' WHERE id=?",    /* LOOKUP_DOCSIZE  */
+
+      "REPLACE INTO %Q.'%q_config' VALUES(?,?)",        /* REPLACE_CONFIG */
+      "SELECT %s FROM %s AS T",                         /* SCAN */
+    };
+    Fts5Config *pC = p->pConfig;
+    char *zSql = 0;
+
+    assert( ArraySize(azStmt)==ArraySize(p->aStmt) );
+
+    switch( eStmt ){
+      case FTS5_STMT_SCAN:
+        zSql = sqlite3_mprintf(azStmt[eStmt],
+            pC->zContentExprlist, pC->zContent
+        );
+        break;
+
+      case FTS5_STMT_SCAN_ASC:
+      case FTS5_STMT_SCAN_DESC:
+        zSql = sqlite3_mprintf(azStmt[eStmt], pC->zContentExprlist,
+            pC->zContent, pC->zContentRowid, pC->zContentRowid,
+            pC->zContentRowid
+        );
+        break;
+
+      case FTS5_STMT_LOOKUP:
+      case FTS5_STMT_LOOKUP2:
+        zSql = sqlite3_mprintf(azStmt[eStmt],
+            pC->zContentExprlist, pC->zContent, pC->zContentRowid
+        );
+        break;
+
+      case FTS5_STMT_INSERT_CONTENT:
+      case FTS5_STMT_REPLACE_CONTENT: {
+        char *zBind = 0;
+        int i;
+
+        assert( pC->eContent==FTS5_CONTENT_NORMAL
+             || pC->eContent==FTS5_CONTENT_UNINDEXED
+        );
+
+        /* Add bindings for the "c*" columns - those that store the actual
+        ** table content. If eContent==NORMAL, then there is one binding
+        ** for each column. Or, if eContent==UNINDEXED, then there are only
+        ** bindings for the UNINDEXED columns. */
+        for(i=0; rc==SQLITE_OK && i<(pC->nCol+1); i++){
+          if( !i || pC->eContent==FTS5_CONTENT_NORMAL || pC->abUnindexed[i-1] ){
+            zBind = sqlite3Fts5Mprintf(&rc, "%z%s?%d", zBind, zBind?",":"",i+1);
+          }
+        }
+
+        /* Add bindings for any "l*" columns. Only non-UNINDEXED columns
+        ** require these.  */
+        if( pC->bLocale && pC->eContent==FTS5_CONTENT_NORMAL ){
+          for(i=0; rc==SQLITE_OK && i<pC->nCol; i++){
+            if( pC->abUnindexed[i]==0 ){
+              zBind = sqlite3Fts5Mprintf(&rc, "%z,?%d", zBind, pC->nCol+i+2);
+            }
+          }
+        }
+
+        zSql = sqlite3Fts5Mprintf(&rc, azStmt[eStmt], pC->zDb, pC->zName,zBind);
+        sqlite3_free(zBind);
+        break;
+      }
+
+      case FTS5_STMT_REPLACE_DOCSIZE:
+        zSql = sqlite3_mprintf(azStmt[eStmt], pC->zDb, pC->zName,
+          (pC->bContentlessDelete ? ",?" : "")
+        );
+        break;
+
+      case FTS5_STMT_LOOKUP_DOCSIZE:
+        zSql = sqlite3_mprintf(azStmt[eStmt],
+            (pC->bContentlessDelete ? ",origin" : ""),
+            pC->zDb, pC->zName
+        );
+        break;
+
+      default:
+        zSql = sqlite3_mprintf(azStmt[eStmt], pC->zDb, pC->zName);
+        break;
+    }
+
+    if( zSql==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      int f = SQLITE_PREPARE_PERSISTENT;
+      if( eStmt>FTS5_STMT_LOOKUP2 ) f |= SQLITE_PREPARE_NO_VTAB;
+      p->pConfig->bLock++;
+      rc = sqlite3_prepare_v3(pC->db, zSql, -1, f, &p->aStmt[eStmt], 0);
+      p->pConfig->bLock--;
+      sqlite3_free(zSql);
+      if( rc!=SQLITE_OK && pzErrMsg ){
+        *pzErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pC->db));
+      }
+      if( rc==SQLITE_ERROR && eStmt>FTS5_STMT_LOOKUP2 && eStmt<FTS5_STMT_SCAN ){
+        /* One of the internal tables - not the %_content table - is missing.
+        ** This counts as a corrupted table.  */
+       rc = SQLITE_CORRUPT;
+      }
+    }
+  }
+
+  *ppStmt = p->aStmt[eStmt];
+  sqlite3_reset(*ppStmt);
+  return rc;
+}
+
+
+static int fts5ExecPrintf(
+  sqlite3 *db,
+  char **pzErr,
+  const char *zFormat,
+  ...
+){
+  int rc;
+  va_list ap;                     /* ... printf arguments */
+  char *zSql;
+
+  va_start(ap, zFormat);
+  zSql = sqlite3_vmprintf(zFormat, ap);
+
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    rc = sqlite3_exec(db, zSql, 0, 0, pzErr);
+    sqlite3_free(zSql);
+  }
+
+  va_end(ap);
+  return rc;
+}
+
+/*
+** Drop all shadow tables. Return SQLITE_OK if successful or an SQLite error
+** code otherwise.
+*/
+static int sqlite3Fts5DropAll(Fts5Config *pConfig){
+  int rc = fts5ExecPrintf(pConfig->db, 0,
+      "DROP TABLE IF EXISTS %Q.'%q_data';"
+      "DROP TABLE IF EXISTS %Q.'%q_idx';"
+      "DROP TABLE IF EXISTS %Q.'%q_config';",
+      pConfig->zDb, pConfig->zName,
+      pConfig->zDb, pConfig->zName,
+      pConfig->zDb, pConfig->zName
+  );
+  if( rc==SQLITE_OK && pConfig->bColumnsize ){
+    rc = fts5ExecPrintf(pConfig->db, 0,
+        "DROP TABLE IF EXISTS %Q.'%q_docsize';",
+        pConfig->zDb, pConfig->zName
+    );
+  }
+  if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_NORMAL ){
+    rc = fts5ExecPrintf(pConfig->db, 0,
+        "DROP TABLE IF EXISTS %Q.'%q_content';",
+        pConfig->zDb, pConfig->zName
+    );
+  }
+  return rc;
+}
+
+static void fts5StorageRenameOne(
+  Fts5Config *pConfig,            /* Current FTS5 configuration */
+  int *pRc,                       /* IN/OUT: Error code */
+  const char *zTail,              /* Tail of table name e.g. "data", "config" */
+  const char *zName               /* New name of FTS5 table */
+){
+  if( *pRc==SQLITE_OK ){
+    *pRc = fts5ExecPrintf(pConfig->db, 0,
+        "ALTER TABLE %Q.'%q_%s' RENAME TO '%q_%s';",
+        pConfig->zDb, pConfig->zName, zTail, zName, zTail
+    );
+  }
+}
+
+static int sqlite3Fts5StorageRename(Fts5Storage *pStorage, const char *zName){
+  Fts5Config *pConfig = pStorage->pConfig;
+  int rc = sqlite3Fts5StorageSync(pStorage);
+
+  fts5StorageRenameOne(pConfig, &rc, "data", zName);
+  fts5StorageRenameOne(pConfig, &rc, "idx", zName);
+  fts5StorageRenameOne(pConfig, &rc, "config", zName);
+  if( pConfig->bColumnsize ){
+    fts5StorageRenameOne(pConfig, &rc, "docsize", zName);
+  }
+  if( pConfig->eContent==FTS5_CONTENT_NORMAL ){
+    fts5StorageRenameOne(pConfig, &rc, "content", zName);
+  }
+  return rc;
+}
+
+/*
+** Create the shadow table named zPost, with definition zDefn. Return
+** SQLITE_OK if successful, or an SQLite error code otherwise.
+*/
+static int sqlite3Fts5CreateTable(
+  Fts5Config *pConfig,            /* FTS5 configuration */
+  const char *zPost,              /* Shadow table to create (e.g. "content") */
+  const char *zDefn,              /* Columns etc. for shadow table */
+  int bWithout,                   /* True for without rowid */
+  char **pzErr                    /* OUT: Error message */
+){
+  int rc;
+  char *zErr = 0;
+
+  rc = fts5ExecPrintf(pConfig->db, &zErr, "CREATE TABLE %Q.'%q_%q'(%s)%s",
+      pConfig->zDb, pConfig->zName, zPost, zDefn,
+#ifndef SQLITE_FTS5_NO_WITHOUT_ROWID
+      bWithout?" WITHOUT ROWID":
+#endif
+      ""
+  );
+  if( zErr ){
+    *pzErr = sqlite3_mprintf(
+        "fts5: error creating shadow table %q_%s: %s",
+        pConfig->zName, zPost, zErr
+    );
+    sqlite3_free(zErr);
+  }
+
+  return rc;
+}
+
+/*
+** Open a new Fts5Index handle. If the bCreate argument is true, create
+** and initialize the underlying tables
+**
+** If successful, set *pp to point to the new object and return SQLITE_OK.
+** Otherwise, set *pp to NULL and return an SQLite error code.
+*/
+static int sqlite3Fts5StorageOpen(
+  Fts5Config *pConfig,
+  Fts5Index *pIndex,
+  int bCreate,
+  Fts5Storage **pp,
+  char **pzErr                    /* OUT: Error message */
+){
+  int rc = SQLITE_OK;
+  Fts5Storage *p;                 /* New object */
+  sqlite3_int64 nByte;            /* Bytes of space to allocate */
+
+  nByte = sizeof(Fts5Storage)               /* Fts5Storage object */
+        + pConfig->nCol * sizeof(i64);      /* Fts5Storage.aTotalSize[] */
+  *pp = p = (Fts5Storage*)sqlite3_malloc64(nByte);
+  if( !p ) return SQLITE_NOMEM;
+
+  memset(p, 0, (size_t)nByte);
+  p->aTotalSize = (i64*)&p[1];
+  p->pConfig = pConfig;
+  p->pIndex = pIndex;
+
+  if( bCreate ){
+    if( pConfig->eContent==FTS5_CONTENT_NORMAL
+     || pConfig->eContent==FTS5_CONTENT_UNINDEXED
+    ){
+      int nDefn = 32 + pConfig->nCol*10;
+      char *zDefn = sqlite3_malloc64(32 + (sqlite3_int64)pConfig->nCol * 20);
+      if( zDefn==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        int i;
+        int iOff;
+        sqlite3_snprintf(nDefn, zDefn, "id INTEGER PRIMARY KEY");
+        iOff = (int)strlen(zDefn);
+        for(i=0; i<pConfig->nCol; i++){
+          if( pConfig->eContent==FTS5_CONTENT_NORMAL
+           || pConfig->abUnindexed[i]
+          ){
+            sqlite3_snprintf(nDefn-iOff, &zDefn[iOff], ", c%d", i);
+            iOff += (int)strlen(&zDefn[iOff]);
+          }
+        }
+        if( pConfig->bLocale ){
+          for(i=0; i<pConfig->nCol; i++){
+            if( pConfig->abUnindexed[i]==0 ){
+              sqlite3_snprintf(nDefn-iOff, &zDefn[iOff], ", l%d", i);
+              iOff += (int)strlen(&zDefn[iOff]);
+            }
+          }
+        }
+        rc = sqlite3Fts5CreateTable(pConfig, "content", zDefn, 0, pzErr);
+      }
+      sqlite3_free(zDefn);
+    }
+
+    if( rc==SQLITE_OK && pConfig->bColumnsize ){
+      const char *zCols = "id INTEGER PRIMARY KEY, sz BLOB";
+      if( pConfig->bContentlessDelete ){
+        zCols = "id INTEGER PRIMARY KEY, sz BLOB, origin INTEGER";
+      }
+      rc = sqlite3Fts5CreateTable(pConfig, "docsize", zCols, 0, pzErr);
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5CreateTable(
+          pConfig, "config", "k PRIMARY KEY, v", 1, pzErr
+      );
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5StorageConfigValue(p, "version", 0, FTS5_CURRENT_VERSION);
+    }
+  }
+
+  if( rc ){
+    sqlite3Fts5StorageClose(p);
+    *pp = 0;
+  }
+  return rc;
+}
+
+/*
+** Close a handle opened by an earlier call to sqlite3Fts5StorageOpen().
+*/
+static int sqlite3Fts5StorageClose(Fts5Storage *p){
+  int rc = SQLITE_OK;
+  if( p ){
+    int i;
+
+    /* Finalize all SQL statements */
+    for(i=0; i<ArraySize(p->aStmt); i++){
+      sqlite3_finalize(p->aStmt[i]);
+    }
+
+    sqlite3_free(p);
+  }
+  return rc;
+}
+
+typedef struct Fts5InsertCtx Fts5InsertCtx;
+struct Fts5InsertCtx {
+  Fts5Storage *pStorage;
+  int iCol;
+  int szCol;                      /* Size of column value in tokens */
+};
+
+/*
+** Tokenization callback used when inserting tokens into the FTS index.
+*/
+static int fts5StorageInsertCallback(
+  void *pContext,                 /* Pointer to Fts5InsertCtx object */
+  int tflags,
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iUnused1,                   /* Start offset of token */
+  int iUnused2                    /* End offset of token */
+){
+  Fts5InsertCtx *pCtx = (Fts5InsertCtx*)pContext;
+  Fts5Index *pIdx = pCtx->pStorage->pIndex;
+  UNUSED_PARAM2(iUnused1, iUnused2);
+  if( nToken>FTS5_MAX_TOKEN_SIZE ) nToken = FTS5_MAX_TOKEN_SIZE;
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 || pCtx->szCol==0 ){
+    pCtx->szCol++;
+  }
+  return sqlite3Fts5IndexWrite(pIdx, pCtx->iCol, pCtx->szCol-1, pToken, nToken);
+}
+
+/*
+** This function is used as part of an UPDATE statement that modifies the
+** rowid of a row. In that case, this function is called first to set
+** Fts5Storage.pSavedRow to point to a statement that may be used to
+** access the original values of the row being deleted - iDel.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+** It is not considered an error if row iDel does not exist. In this case
+** pSavedRow is not set and SQLITE_OK returned.
+*/
+static int sqlite3Fts5StorageFindDeleteRow(Fts5Storage *p, i64 iDel){
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pSeek = 0;
+
+  assert( p->pSavedRow==0 );
+  rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP+1, &pSeek, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pSeek, 1, iDel);
+    if( sqlite3_step(pSeek)!=SQLITE_ROW ){
+      rc = sqlite3_reset(pSeek);
+    }else{
+      p->pSavedRow = pSeek;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** If a row with rowid iDel is present in the %_content table, add the
+** delete-markers to the FTS index necessary to delete it. Do not actually
+** remove the %_content row at this time though.
+**
+** If parameter bSaveRow is true, then Fts5Storage.pSavedRow is left
+** pointing to a statement (FTS5_STMT_LOOKUP2) that may be used to access
+** the original values of the row being deleted. This is used by UPDATE
+** statements.
+*/
+static int fts5StorageDeleteFromIndex(
+  Fts5Storage *p,
+  i64 iDel,
+  sqlite3_value **apVal,
+  int bSaveRow                    /* True to set pSavedRow */
+){
+  Fts5Config *pConfig = p->pConfig;
+  sqlite3_stmt *pSeek = 0;        /* SELECT to read row iDel from %_data */
+  int rc = SQLITE_OK;             /* Return code */
+  int rc2;                        /* sqlite3_reset() return code */
+  int iCol;
+  Fts5InsertCtx ctx;
+
+  assert( bSaveRow==0 || apVal==0 );
+  assert( bSaveRow==0 || bSaveRow==1 );
+  assert( FTS5_STMT_LOOKUP2==FTS5_STMT_LOOKUP+1 );
+
+  if( apVal==0 ){
+    if( p->pSavedRow && bSaveRow ){
+      pSeek = p->pSavedRow;
+      p->pSavedRow = 0;
+    }else{
+      rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP+bSaveRow, &pSeek, 0);
+      if( rc!=SQLITE_OK ) return rc;
+      sqlite3_bind_int64(pSeek, 1, iDel);
+      if( sqlite3_step(pSeek)!=SQLITE_ROW ){
+        return sqlite3_reset(pSeek);
+      }
+    }
+  }
+
+  ctx.pStorage = p;
+  ctx.iCol = -1;
+  for(iCol=1; rc==SQLITE_OK && iCol<=pConfig->nCol; iCol++){
+    if( pConfig->abUnindexed[iCol-1]==0 ){
+      sqlite3_value *pVal = 0;
+      const char *pText = 0;
+      int nText = 0;
+      const char *pLoc = 0;
+      int nLoc = 0;
+
+      assert( pSeek==0 || apVal==0 );
+      assert( pSeek!=0 || apVal!=0 );
+      if( pSeek ){
+        pVal = sqlite3_column_value(pSeek, iCol);
+      }else{
+        pVal = apVal[iCol-1];
+      }
+
+      if( pConfig->bLocale && sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+        rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+      }else{
+        pText = (const char*)sqlite3_value_text(pVal);
+        nText = sqlite3_value_bytes(pVal);
+        if( pConfig->bLocale && pSeek ){
+          pLoc = (const char*)sqlite3_column_text(pSeek, iCol + pConfig->nCol);
+          nLoc = sqlite3_column_bytes(pSeek, iCol + pConfig->nCol);
+        }
+      }
+
+      if( rc==SQLITE_OK ){
+        sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+        ctx.szCol = 0;
+        rc = sqlite3Fts5Tokenize(pConfig, FTS5_TOKENIZE_DOCUMENT,
+            pText, nText, (void*)&ctx, fts5StorageInsertCallback
+        );
+        p->aTotalSize[iCol-1] -= (i64)ctx.szCol;
+        if( rc==SQLITE_OK && p->aTotalSize[iCol-1]<0 ){
+          rc = FTS5_CORRUPT;
+        }
+        sqlite3Fts5ClearLocale(pConfig);
+      }
+    }
+  }
+  if( rc==SQLITE_OK && p->nTotalRow<1 ){
+    rc = FTS5_CORRUPT;
+  }else{
+    p->nTotalRow--;
+  }
+
+  if( rc==SQLITE_OK && bSaveRow ){
+    assert( p->pSavedRow==0 );
+    p->pSavedRow = pSeek;
+  }else{
+    rc2 = sqlite3_reset(pSeek);
+    if( rc==SQLITE_OK ) rc = rc2;
+  }
+  return rc;
+}
+
+/*
+** Reset any saved statement pSavedRow. Zero pSavedRow as well. This
+** should be called by the xUpdate() method of the fts5 table before
+** returning from any operation that may have set Fts5Storage.pSavedRow.
+*/
+static void sqlite3Fts5StorageReleaseDeleteRow(Fts5Storage *pStorage){
+  assert( pStorage->pSavedRow==0
+       || pStorage->pSavedRow==pStorage->aStmt[FTS5_STMT_LOOKUP2]
+  );
+  sqlite3_reset(pStorage->pSavedRow);
+  pStorage->pSavedRow = 0;
+}
+
+/*
+** This function is called to process a DELETE on a contentless_delete=1
+** table. It adds the tombstone required to delete the entry with rowid
+** iDel. If successful, SQLITE_OK is returned. Or, if an error occurs,
+** an SQLite error code.
+*/
+static int fts5StorageContentlessDelete(Fts5Storage *p, i64 iDel){
+  i64 iOrigin = 0;
+  sqlite3_stmt *pLookup = 0;
+  int rc = SQLITE_OK;
+
+  assert( p->pConfig->bContentlessDelete );
+  assert( p->pConfig->eContent==FTS5_CONTENT_NONE
+       || p->pConfig->eContent==FTS5_CONTENT_UNINDEXED
+  );
+
+  /* Look up the origin of the document in the %_docsize table. Store
+  ** this in stack variable iOrigin.  */
+  rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP_DOCSIZE, &pLookup, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_int64(pLookup, 1, iDel);
+    if( SQLITE_ROW==sqlite3_step(pLookup) ){
+      iOrigin = sqlite3_column_int64(pLookup, 1);
+    }
+    rc = sqlite3_reset(pLookup);
+  }
+
+  if( rc==SQLITE_OK && iOrigin!=0 ){
+    rc = sqlite3Fts5IndexContentlessDelete(p->pIndex, iOrigin, iDel);
+  }
+
+  return rc;
+}
+
+/*
+** Insert a record into the %_docsize table. Specifically, do:
+**
+**   INSERT OR REPLACE INTO %_docsize(id, sz) VALUES(iRowid, pBuf);
+**
+** If there is no %_docsize table (as happens if the columnsize=0 option
+** is specified when the FTS5 table is created), this function is a no-op.
+*/
+static int fts5StorageInsertDocsize(
+  Fts5Storage *p,                 /* Storage module to write to */
+  i64 iRowid,                     /* id value */
+  Fts5Buffer *pBuf                /* sz value */
+){
+  int rc = SQLITE_OK;
+  if( p->pConfig->bColumnsize ){
+    sqlite3_stmt *pReplace = 0;
+    rc = fts5StorageGetStmt(p, FTS5_STMT_REPLACE_DOCSIZE, &pReplace, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pReplace, 1, iRowid);
+      if( p->pConfig->bContentlessDelete ){
+        i64 iOrigin = 0;
+        rc = sqlite3Fts5IndexGetOrigin(p->pIndex, &iOrigin);
+        sqlite3_bind_int64(pReplace, 3, iOrigin);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_blob(pReplace, 2, pBuf->p, pBuf->n, SQLITE_STATIC);
+      sqlite3_step(pReplace);
+      rc = sqlite3_reset(pReplace);
+      sqlite3_bind_null(pReplace, 2);
+    }
+  }
+  return rc;
+}
+
+/*
+** Load the contents of the "averages" record from disk into the
+** p->nTotalRow and p->aTotalSize[] variables. If successful, and if
+** argument bCache is true, set the p->bTotalsValid flag to indicate
+** that the contents of aTotalSize[] and nTotalRow are valid until
+** further notice.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int fts5StorageLoadTotals(Fts5Storage *p, int bCache){
+  int rc = SQLITE_OK;
+  if( p->bTotalsValid==0 ){
+    rc = sqlite3Fts5IndexGetAverages(p->pIndex, &p->nTotalRow, p->aTotalSize);
+    p->bTotalsValid = bCache;
+  }
+  return rc;
+}
+
+/*
+** Store the current contents of the p->nTotalRow and p->aTotalSize[]
+** variables in the "averages" record on disk.
+**
+** Return SQLITE_OK if successful, or an SQLite error code if an error
+** occurs.
+*/
+static int fts5StorageSaveTotals(Fts5Storage *p){
+  int nCol = p->pConfig->nCol;
+  int i;
+  Fts5Buffer buf;
+  int rc = SQLITE_OK;
+  memset(&buf, 0, sizeof(buf));
+
+  sqlite3Fts5BufferAppendVarint(&rc, &buf, p->nTotalRow);
+  for(i=0; i<nCol; i++){
+    sqlite3Fts5BufferAppendVarint(&rc, &buf, p->aTotalSize[i]);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexSetAverages(p->pIndex, buf.p, buf.n);
+  }
+  sqlite3_free(buf.p);
+
+  return rc;
+}
+
+/*
+** Remove a row from the FTS table.
+*/
+static int sqlite3Fts5StorageDelete(
+  Fts5Storage *p,                 /* Storage object */
+  i64 iDel,                       /* Rowid to delete from table */
+  sqlite3_value **apVal,          /* Optional - values to remove from index */
+  int bSaveRow                    /* If true, set pSavedRow for deleted row */
+){
+  Fts5Config *pConfig = p->pConfig;
+  int rc;
+  sqlite3_stmt *pDel = 0;
+
+  assert( pConfig->eContent!=FTS5_CONTENT_NORMAL || apVal==0 );
+  rc = fts5StorageLoadTotals(p, 1);
+
+  /* Delete the index records */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexBeginWrite(p->pIndex, 1, iDel);
+  }
+
+  if( rc==SQLITE_OK ){
+    if( p->pConfig->bContentlessDelete ){
+      rc = fts5StorageContentlessDelete(p, iDel);
+      if( rc==SQLITE_OK
+       && bSaveRow
+       && p->pConfig->eContent==FTS5_CONTENT_UNINDEXED
+      ){
+        rc = sqlite3Fts5StorageFindDeleteRow(p, iDel);
+      }
+    }else{
+      rc = fts5StorageDeleteFromIndex(p, iDel, apVal, bSaveRow);
+    }
+  }
+
+  /* Delete the %_docsize record */
+  if( rc==SQLITE_OK && pConfig->bColumnsize ){
+    rc = fts5StorageGetStmt(p, FTS5_STMT_DELETE_DOCSIZE, &pDel, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDel, 1, iDel);
+      sqlite3_step(pDel);
+      rc = sqlite3_reset(pDel);
+    }
+  }
+
+  /* Delete the %_content record */
+  if( pConfig->eContent==FTS5_CONTENT_NORMAL
+   || pConfig->eContent==FTS5_CONTENT_UNINDEXED
+  ){
+    if( rc==SQLITE_OK ){
+      rc = fts5StorageGetStmt(p, FTS5_STMT_DELETE_CONTENT, &pDel, 0);
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_int64(pDel, 1, iDel);
+      sqlite3_step(pDel);
+      rc = sqlite3_reset(pDel);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Delete all entries in the FTS5 index.
+*/
+static int sqlite3Fts5StorageDeleteAll(Fts5Storage *p){
+  Fts5Config *pConfig = p->pConfig;
+  int rc;
+
+  p->bTotalsValid = 0;
+
+  /* Delete the contents of the %_data and %_docsize tables. */
+  rc = fts5ExecPrintf(pConfig->db, 0,
+      "DELETE FROM %Q.'%q_data';"
+      "DELETE FROM %Q.'%q_idx';",
+      pConfig->zDb, pConfig->zName,
+      pConfig->zDb, pConfig->zName
+  );
+  if( rc==SQLITE_OK && pConfig->bColumnsize ){
+    rc = fts5ExecPrintf(pConfig->db, 0,
+        "DELETE FROM %Q.'%q_docsize';", pConfig->zDb, pConfig->zName
+    );
+  }
+
+  if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_UNINDEXED ){
+    rc = fts5ExecPrintf(pConfig->db, 0,
+        "DELETE FROM %Q.'%q_content';", pConfig->zDb, pConfig->zName
+    );
+  }
+
+  /* Reinitialize the %_data table. This call creates the initial structure
+  ** and averages records.  */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexReinit(p->pIndex);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageConfigValue(p, "version", 0, FTS5_CURRENT_VERSION);
+  }
+  return rc;
+}
+
+static int sqlite3Fts5StorageRebuild(Fts5Storage *p){
+  Fts5Buffer buf = {0,0,0};
+  Fts5Config *pConfig = p->pConfig;
+  sqlite3_stmt *pScan = 0;
+  Fts5InsertCtx ctx;
+  int rc, rc2;
+
+  memset(&ctx, 0, sizeof(Fts5InsertCtx));
+  ctx.pStorage = p;
+  rc = sqlite3Fts5StorageDeleteAll(p);
+  if( rc==SQLITE_OK ){
+    rc = fts5StorageLoadTotals(p, 1);
+  }
+
+  if( rc==SQLITE_OK ){
+    rc = fts5StorageGetStmt(p, FTS5_STMT_SCAN, &pScan, pConfig->pzErrmsg);
+  }
+
+  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pScan) ){
+    i64 iRowid = sqlite3_column_int64(pScan, 0);
+
+    sqlite3Fts5BufferZero(&buf);
+    rc = sqlite3Fts5IndexBeginWrite(p->pIndex, 0, iRowid);
+    for(ctx.iCol=0; rc==SQLITE_OK && ctx.iCol<pConfig->nCol; ctx.iCol++){
+      ctx.szCol = 0;
+      if( pConfig->abUnindexed[ctx.iCol]==0 ){
+        int nText = 0;            /* Size of pText in bytes */
+        const char *pText = 0;    /* Pointer to buffer containing text value */
+        int nLoc = 0;             /* Size of pLoc in bytes */
+        const char *pLoc = 0;     /* Pointer to buffer containing text value */
+
+        sqlite3_value *pVal = sqlite3_column_value(pScan, ctx.iCol+1);
+        if( pConfig->eContent==FTS5_CONTENT_EXTERNAL
+         && sqlite3Fts5IsLocaleValue(pConfig, pVal)
+        ){
+          rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+        }else{
+          pText = (const char*)sqlite3_value_text(pVal);
+          nText = sqlite3_value_bytes(pVal);
+          if( pConfig->bLocale ){
+            int iCol = ctx.iCol + 1 + pConfig->nCol;
+            pLoc = (const char*)sqlite3_column_text(pScan, iCol);
+            nLoc = sqlite3_column_bytes(pScan, iCol);
+          }
+        }
+
+        if( rc==SQLITE_OK ){
+          sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+          rc = sqlite3Fts5Tokenize(pConfig,
+              FTS5_TOKENIZE_DOCUMENT,
+              pText, nText,
+              (void*)&ctx,
+              fts5StorageInsertCallback
+          );
+          sqlite3Fts5ClearLocale(pConfig);
+        }
+      }
+      sqlite3Fts5BufferAppendVarint(&rc, &buf, ctx.szCol);
+      p->aTotalSize[ctx.iCol] += (i64)ctx.szCol;
+    }
+    p->nTotalRow++;
+
+    if( rc==SQLITE_OK ){
+      rc = fts5StorageInsertDocsize(p, iRowid, &buf);
+    }
+  }
+  sqlite3_free(buf.p);
+  rc2 = sqlite3_reset(pScan);
+  if( rc==SQLITE_OK ) rc = rc2;
+
+  /* Write the averages record */
+  if( rc==SQLITE_OK ){
+    rc = fts5StorageSaveTotals(p);
+  }
+  return rc;
+}
+
+static int sqlite3Fts5StorageOptimize(Fts5Storage *p){
+  return sqlite3Fts5IndexOptimize(p->pIndex);
+}
+
+static int sqlite3Fts5StorageMerge(Fts5Storage *p, int nMerge){
+  return sqlite3Fts5IndexMerge(p->pIndex, nMerge);
+}
+
+static int sqlite3Fts5StorageReset(Fts5Storage *p){
+  return sqlite3Fts5IndexReset(p->pIndex);
+}
+
+/*
+** Allocate a new rowid. This is used for "external content" tables when
+** a NULL value is inserted into the rowid column. The new rowid is allocated
+** by inserting a dummy row into the %_docsize table. The dummy will be
+** overwritten later.
+**
+** If the %_docsize table does not exist, SQLITE_MISMATCH is returned. In
+** this case the user is required to provide a rowid explicitly.
+*/
+static int fts5StorageNewRowid(Fts5Storage *p, i64 *piRowid){
+  int rc = SQLITE_MISMATCH;
+  if( p->pConfig->bColumnsize ){
+    sqlite3_stmt *pReplace = 0;
+    rc = fts5StorageGetStmt(p, FTS5_STMT_REPLACE_DOCSIZE, &pReplace, 0);
+    if( rc==SQLITE_OK ){
+      sqlite3_bind_null(pReplace, 1);
+      sqlite3_bind_null(pReplace, 2);
+      sqlite3_step(pReplace);
+      rc = sqlite3_reset(pReplace);
+    }
+    if( rc==SQLITE_OK ){
+      *piRowid = sqlite3_last_insert_rowid(p->pConfig->db);
+    }
+  }
+  return rc;
+}
+
+/*
+** Insert a new row into the FTS content table.
+*/
+static int sqlite3Fts5StorageContentInsert(
+  Fts5Storage *p,
+  int bReplace,                   /* True to use REPLACE instead of INSERT */
+  sqlite3_value **apVal,
+  i64 *piRowid
+){
+  Fts5Config *pConfig = p->pConfig;
+  int rc = SQLITE_OK;
+
+  /* Insert the new row into the %_content table. */
+  if( pConfig->eContent!=FTS5_CONTENT_NORMAL
+   && pConfig->eContent!=FTS5_CONTENT_UNINDEXED
+  ){
+    if( sqlite3_value_type(apVal[1])==SQLITE_INTEGER ){
+      *piRowid = sqlite3_value_int64(apVal[1]);
+    }else{
+      rc = fts5StorageNewRowid(p, piRowid);
+    }
+  }else{
+    sqlite3_stmt *pInsert = 0;    /* Statement to write %_content table */
+    int i;                        /* Counter variable */
+
+    assert( FTS5_STMT_INSERT_CONTENT+1==FTS5_STMT_REPLACE_CONTENT );
+    assert( bReplace==0 || bReplace==1 );
+    rc = fts5StorageGetStmt(p, FTS5_STMT_INSERT_CONTENT+bReplace, &pInsert, 0);
+    if( pInsert ) sqlite3_clear_bindings(pInsert);
+
+    /* Bind the rowid value */
+    sqlite3_bind_value(pInsert, 1, apVal[1]);
+
+    /* Loop through values for user-defined columns. i=2 is the leftmost
+    ** user-defined column. As is column 1 of pSavedRow.  */
+    for(i=2; rc==SQLITE_OK && i<=pConfig->nCol+1; i++){
+      int bUnindexed = pConfig->abUnindexed[i-2];
+      if( pConfig->eContent==FTS5_CONTENT_NORMAL || bUnindexed ){
+        sqlite3_value *pVal = apVal[i];
+
+        if( sqlite3_value_nochange(pVal) && p->pSavedRow ){
+          /* This is an UPDATE statement, and user-defined column (i-2) was not
+          ** modified.  Retrieve the value from Fts5Storage.pSavedRow.  */
+          pVal = sqlite3_column_value(p->pSavedRow, i-1);
+          if( pConfig->bLocale && bUnindexed==0 ){
+            sqlite3_bind_value(pInsert, pConfig->nCol + i,
+                sqlite3_column_value(p->pSavedRow, pConfig->nCol + i - 1)
+            );
+          }
+        }else if( sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+          const char *pText = 0;
+          const char *pLoc = 0;
+          int nText = 0;
+          int nLoc = 0;
+          assert( pConfig->bLocale );
+
+          rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+          if( rc==SQLITE_OK ){
+            sqlite3_bind_text(pInsert, i, pText, nText, SQLITE_TRANSIENT);
+            if( bUnindexed==0 ){
+              int iLoc = pConfig->nCol + i;
+              sqlite3_bind_text(pInsert, iLoc, pLoc, nLoc, SQLITE_TRANSIENT);
+            }
+          }
+
+          continue;
+        }
+
+        rc = sqlite3_bind_value(pInsert, i, pVal);
+      }
+    }
+    if( rc==SQLITE_OK ){
+      sqlite3_step(pInsert);
+      rc = sqlite3_reset(pInsert);
+    }
+    *piRowid = sqlite3_last_insert_rowid(pConfig->db);
+  }
+
+  return rc;
+}
+
+/*
+** Insert new entries into the FTS index and %_docsize table.
+*/
+static int sqlite3Fts5StorageIndexInsert(
+  Fts5Storage *p,
+  sqlite3_value **apVal,
+  i64 iRowid
+){
+  Fts5Config *pConfig = p->pConfig;
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5InsertCtx ctx;              /* Tokenization callback context object */
+  Fts5Buffer buf;                 /* Buffer used to build up %_docsize blob */
+
+  memset(&buf, 0, sizeof(Fts5Buffer));
+  ctx.pStorage = p;
+  rc = fts5StorageLoadTotals(p, 1);
+
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexBeginWrite(p->pIndex, 0, iRowid);
+  }
+  for(ctx.iCol=0; rc==SQLITE_OK && ctx.iCol<pConfig->nCol; ctx.iCol++){
+    ctx.szCol = 0;
+    if( pConfig->abUnindexed[ctx.iCol]==0 ){
+      int nText = 0;              /* Size of pText in bytes */
+      const char *pText = 0;      /* Pointer to buffer containing text value */
+      int nLoc = 0;               /* Size of pText in bytes */
+      const char *pLoc = 0;       /* Pointer to buffer containing text value */
+
+      sqlite3_value *pVal = apVal[ctx.iCol+2];
+      if( p->pSavedRow && sqlite3_value_nochange(pVal) ){
+        pVal = sqlite3_column_value(p->pSavedRow, ctx.iCol+1);
+        if( pConfig->eContent==FTS5_CONTENT_NORMAL && pConfig->bLocale ){
+          int iCol = ctx.iCol + 1 + pConfig->nCol;
+          pLoc = (const char*)sqlite3_column_text(p->pSavedRow, iCol);
+          nLoc = sqlite3_column_bytes(p->pSavedRow, iCol);
+        }
+      }else{
+        pVal = apVal[ctx.iCol+2];
+      }
+
+      if( pConfig->bLocale && sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
+        rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
+      }else{
+        pText = (const char*)sqlite3_value_text(pVal);
+        nText = sqlite3_value_bytes(pVal);
+      }
+
+      if( rc==SQLITE_OK ){
+        sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+        rc = sqlite3Fts5Tokenize(pConfig,
+            FTS5_TOKENIZE_DOCUMENT, pText, nText, (void*)&ctx,
+            fts5StorageInsertCallback
+        );
+        sqlite3Fts5ClearLocale(pConfig);
+      }
+    }
+    sqlite3Fts5BufferAppendVarint(&rc, &buf, ctx.szCol);
+    p->aTotalSize[ctx.iCol] += (i64)ctx.szCol;
+  }
+  p->nTotalRow++;
+
+  /* Write the %_docsize record */
+  if( rc==SQLITE_OK ){
+    rc = fts5StorageInsertDocsize(p, iRowid, &buf);
+  }
+  sqlite3_free(buf.p);
+
+  return rc;
+}
+
+static int fts5StorageCount(Fts5Storage *p, const char *zSuffix, i64 *pnRow){
+  Fts5Config *pConfig = p->pConfig;
+  char *zSql;
+  int rc;
+
+  zSql = sqlite3_mprintf("SELECT count(*) FROM %Q.'%q_%s'",
+      pConfig->zDb, pConfig->zName, zSuffix
+  );
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    sqlite3_stmt *pCnt = 0;
+    rc = sqlite3_prepare_v2(pConfig->db, zSql, -1, &pCnt, 0);
+    if( rc==SQLITE_OK ){
+      if( SQLITE_ROW==sqlite3_step(pCnt) ){
+        *pnRow = sqlite3_column_int64(pCnt, 0);
+      }
+      rc = sqlite3_finalize(pCnt);
+    }
+  }
+
+  sqlite3_free(zSql);
+  return rc;
+}
+
+/*
+** Context object used by sqlite3Fts5StorageIntegrity().
+*/
+typedef struct Fts5IntegrityCtx Fts5IntegrityCtx;
+struct Fts5IntegrityCtx {
+  i64 iRowid;
+  int iCol;
+  int szCol;
+  u64 cksum;
+  Fts5Termset *pTermset;
+  Fts5Config *pConfig;
+};
+
+
+/*
+** Tokenization callback used by integrity check.
+*/
+static int fts5StorageIntegrityCallback(
+  void *pContext,                 /* Pointer to Fts5IntegrityCtx object */
+  int tflags,
+  const char *pToken,             /* Buffer containing token */
+  int nToken,                     /* Size of token in bytes */
+  int iUnused1,                   /* Start offset of token */
+  int iUnused2                    /* End offset of token */
+){
+  Fts5IntegrityCtx *pCtx = (Fts5IntegrityCtx*)pContext;
+  Fts5Termset *pTermset = pCtx->pTermset;
+  int bPresent;
+  int ii;
+  int rc = SQLITE_OK;
+  int iPos;
+  int iCol;
+
+  UNUSED_PARAM2(iUnused1, iUnused2);
+  if( nToken>FTS5_MAX_TOKEN_SIZE ) nToken = FTS5_MAX_TOKEN_SIZE;
+
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 || pCtx->szCol==0 ){
+    pCtx->szCol++;
+  }
+
+  switch( pCtx->pConfig->eDetail ){
+    case FTS5_DETAIL_FULL:
+      iPos = pCtx->szCol-1;
+      iCol = pCtx->iCol;
+      break;
+
+    case FTS5_DETAIL_COLUMNS:
+      iPos = pCtx->iCol;
+      iCol = 0;
+      break;
+
+    default:
+      assert( pCtx->pConfig->eDetail==FTS5_DETAIL_NONE );
+      iPos = 0;
+      iCol = 0;
+      break;
+  }
+
+  rc = sqlite3Fts5TermsetAdd(pTermset, 0, pToken, nToken, &bPresent);
+  if( rc==SQLITE_OK && bPresent==0 ){
+    pCtx->cksum ^= sqlite3Fts5IndexEntryCksum(
+        pCtx->iRowid, iCol, iPos, 0, pToken, nToken
+    );
+  }
+
+  for(ii=0; rc==SQLITE_OK && ii<pCtx->pConfig->nPrefix; ii++){
+    const int nChar = pCtx->pConfig->aPrefix[ii];
+    int nByte = sqlite3Fts5IndexCharlenToBytelen(pToken, nToken, nChar);
+    if( nByte ){
+      rc = sqlite3Fts5TermsetAdd(pTermset, ii+1, pToken, nByte, &bPresent);
+      if( bPresent==0 ){
+        pCtx->cksum ^= sqlite3Fts5IndexEntryCksum(
+            pCtx->iRowid, iCol, iPos, ii+1, pToken, nByte
+        );
+      }
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Check that the contents of the FTS index match that of the %_content
+** table. Return SQLITE_OK if they do, or SQLITE_CORRUPT if not. Return
+** some other SQLite error code if an error occurs while attempting to
+** determine this.
+*/
+static int sqlite3Fts5StorageIntegrity(Fts5Storage *p, int iArg){
+  Fts5Config *pConfig = p->pConfig;
+  int rc = SQLITE_OK;             /* Return code */
+  int *aColSize;                  /* Array of size pConfig->nCol */
+  i64 *aTotalSize;                /* Array of size pConfig->nCol */
+  Fts5IntegrityCtx ctx;
+  sqlite3_stmt *pScan;
+  int bUseCksum;
+
+  memset(&ctx, 0, sizeof(Fts5IntegrityCtx));
+  ctx.pConfig = p->pConfig;
+  aTotalSize = (i64*)sqlite3_malloc64(pConfig->nCol*(sizeof(int)+sizeof(i64)));
+  if( !aTotalSize ) return SQLITE_NOMEM;
+  aColSize = (int*)&aTotalSize[pConfig->nCol];
+  memset(aTotalSize, 0, sizeof(i64) * pConfig->nCol);
+
+  bUseCksum = (pConfig->eContent==FTS5_CONTENT_NORMAL
+           || (pConfig->eContent==FTS5_CONTENT_EXTERNAL && iArg)
+  );
+  if( bUseCksum ){
+    /* Generate the expected index checksum based on the contents of the
+    ** %_content table. This block stores the checksum in ctx.cksum. */
+    rc = fts5StorageGetStmt(p, FTS5_STMT_SCAN, &pScan, 0);
+    if( rc==SQLITE_OK ){
+      int rc2;
+      while( SQLITE_ROW==sqlite3_step(pScan) ){
+        int i;
+        ctx.iRowid = sqlite3_column_int64(pScan, 0);
+        ctx.szCol = 0;
+        if( pConfig->bColumnsize ){
+          rc = sqlite3Fts5StorageDocsize(p, ctx.iRowid, aColSize);
+        }
+        if( rc==SQLITE_OK && pConfig->eDetail==FTS5_DETAIL_NONE ){
+          rc = sqlite3Fts5TermsetNew(&ctx.pTermset);
+        }
+        for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
+          if( pConfig->abUnindexed[i]==0 ){
+            const char *pText = 0;
+            int nText = 0;
+            const char *pLoc = 0;
+            int nLoc = 0;
+            sqlite3_value *pVal = sqlite3_column_value(pScan, i+1);
+
+            if( pConfig->eContent==FTS5_CONTENT_EXTERNAL
+             && sqlite3Fts5IsLocaleValue(pConfig, pVal)
+            ){
+              rc = sqlite3Fts5DecodeLocaleValue(
+                  pVal, &pText, &nText, &pLoc, &nLoc
+              );
+            }else{
+              if( pConfig->eContent==FTS5_CONTENT_NORMAL && pConfig->bLocale ){
+                int iCol = i + 1 + pConfig->nCol;
+                pLoc = (const char*)sqlite3_column_text(pScan, iCol);
+                nLoc = sqlite3_column_bytes(pScan, iCol);
+              }
+              pText = (const char*)sqlite3_value_text(pVal);
+              nText = sqlite3_value_bytes(pVal);
+            }
+
+            ctx.iCol = i;
+            ctx.szCol = 0;
+
+            if( rc==SQLITE_OK && pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+              rc = sqlite3Fts5TermsetNew(&ctx.pTermset);
+            }
+
+            if( rc==SQLITE_OK ){
+              sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
+              rc = sqlite3Fts5Tokenize(pConfig,
+                  FTS5_TOKENIZE_DOCUMENT,
+                  pText, nText,
+                  (void*)&ctx,
+                  fts5StorageIntegrityCallback
+              );
+              sqlite3Fts5ClearLocale(pConfig);
+            }
+
+            /* If this is not a columnsize=0 database, check that the number
+            ** of tokens in the value matches the aColSize[] value read from
+            ** the %_docsize table.  */
+            if( rc==SQLITE_OK
+             && pConfig->bColumnsize
+             && ctx.szCol!=aColSize[i]
+            ){
+              rc = FTS5_CORRUPT;
+            }
+            aTotalSize[i] += ctx.szCol;
+            if( pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+              sqlite3Fts5TermsetFree(ctx.pTermset);
+              ctx.pTermset = 0;
+            }
+          }
+        }
+        sqlite3Fts5TermsetFree(ctx.pTermset);
+        ctx.pTermset = 0;
+
+        if( rc!=SQLITE_OK ) break;
+      }
+      rc2 = sqlite3_reset(pScan);
+      if( rc==SQLITE_OK ) rc = rc2;
+    }
+
+    /* Test that the "totals" (sometimes called "averages") record looks Ok */
+    if( rc==SQLITE_OK ){
+      int i;
+      rc = fts5StorageLoadTotals(p, 0);
+      for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
+        if( p->aTotalSize[i]!=aTotalSize[i] ) rc = FTS5_CORRUPT;
+      }
+    }
+
+    /* Check that the %_docsize and %_content tables contain the expected
+    ** number of rows.  */
+    if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_NORMAL ){
+      i64 nRow = 0;
+      rc = fts5StorageCount(p, "content", &nRow);
+      if( rc==SQLITE_OK && nRow!=p->nTotalRow ) rc = FTS5_CORRUPT;
+    }
+    if( rc==SQLITE_OK && pConfig->bColumnsize ){
+      i64 nRow = 0;
+      rc = fts5StorageCount(p, "docsize", &nRow);
+      if( rc==SQLITE_OK && nRow!=p->nTotalRow ) rc = FTS5_CORRUPT;
+    }
+  }
+
+  /* Pass the expected checksum down to the FTS index module. It will
+  ** verify, amongst other things, that it matches the checksum generated by
+  ** inspecting the index itself.  */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexIntegrityCheck(p->pIndex, ctx.cksum, bUseCksum);
+  }
+
+  sqlite3_free(aTotalSize);
+  return rc;
+}
+
+/*
+** Obtain an SQLite statement handle that may be used to read data from the
+** %_content table.
+*/
+static int sqlite3Fts5StorageStmt(
+  Fts5Storage *p,
+  int eStmt,
+  sqlite3_stmt **pp,
+  char **pzErrMsg
+){
+  int rc;
+  assert( eStmt==FTS5_STMT_SCAN_ASC
+       || eStmt==FTS5_STMT_SCAN_DESC
+       || eStmt==FTS5_STMT_LOOKUP
+  );
+  rc = fts5StorageGetStmt(p, eStmt, pp, pzErrMsg);
+  if( rc==SQLITE_OK ){
+    assert( p->aStmt[eStmt]==*pp );
+    p->aStmt[eStmt] = 0;
+  }
+  return rc;
+}
+
+/*
+** Release an SQLite statement handle obtained via an earlier call to
+** sqlite3Fts5StorageStmt(). The eStmt parameter passed to this function
+** must match that passed to the sqlite3Fts5StorageStmt() call.
+*/
+static void sqlite3Fts5StorageStmtRelease(
+  Fts5Storage *p,
+  int eStmt,
+  sqlite3_stmt *pStmt
+){
+  assert( eStmt==FTS5_STMT_SCAN_ASC
+       || eStmt==FTS5_STMT_SCAN_DESC
+       || eStmt==FTS5_STMT_LOOKUP
+  );
+  if( p->aStmt[eStmt]==0 ){
+    sqlite3_reset(pStmt);
+    p->aStmt[eStmt] = pStmt;
+  }else{
+    sqlite3_finalize(pStmt);
+  }
+}
+
+static int fts5StorageDecodeSizeArray(
+  int *aCol, int nCol,            /* Array to populate */
+  const u8 *aBlob, int nBlob      /* Record to read varints from */
+){
+  int i;
+  int iOff = 0;
+  for(i=0; i<nCol; i++){
+    if( iOff>=nBlob ) return 1;
+    iOff += fts5GetVarint32(&aBlob[iOff], aCol[i]);
+  }
+  return (iOff!=nBlob);
+}
+
+/*
+** Argument aCol points to an array of integers containing one entry for
+** each table column. This function reads the %_docsize record for the
+** specified rowid and populates aCol[] with the results.
+**
+** An SQLite error code is returned if an error occurs, or SQLITE_OK
+** otherwise.
+*/
+static int sqlite3Fts5StorageDocsize(Fts5Storage *p, i64 iRowid, int *aCol){
+  int nCol = p->pConfig->nCol;    /* Number of user columns in table */
+  sqlite3_stmt *pLookup = 0;      /* Statement to query %_docsize */
+  int rc;                         /* Return Code */
+
+  assert( p->pConfig->bColumnsize );
+  rc = fts5StorageGetStmt(p, FTS5_STMT_LOOKUP_DOCSIZE, &pLookup, 0);
+  if( pLookup ){
+    int bCorrupt = 1;
+    assert( rc==SQLITE_OK );
+    sqlite3_bind_int64(pLookup, 1, iRowid);
+    if( SQLITE_ROW==sqlite3_step(pLookup) ){
+      const u8 *aBlob = sqlite3_column_blob(pLookup, 0);
+      int nBlob = sqlite3_column_bytes(pLookup, 0);
+      if( 0==fts5StorageDecodeSizeArray(aCol, nCol, aBlob, nBlob) ){
+        bCorrupt = 0;
+      }
+    }
+    rc = sqlite3_reset(pLookup);
+    if( bCorrupt && rc==SQLITE_OK ){
+      rc = FTS5_CORRUPT;
+    }
+  }else{
+    assert( rc!=SQLITE_OK );
+  }
+
+  return rc;
+}
+
+static int sqlite3Fts5StorageSize(Fts5Storage *p, int iCol, i64 *pnToken){
+  int rc = fts5StorageLoadTotals(p, 0);
+  if( rc==SQLITE_OK ){
+    *pnToken = 0;
+    if( iCol<0 ){
+      int i;
+      for(i=0; i<p->pConfig->nCol; i++){
+        *pnToken += p->aTotalSize[i];
+      }
+    }else if( iCol<p->pConfig->nCol ){
+      *pnToken = p->aTotalSize[iCol];
+    }else{
+      rc = SQLITE_RANGE;
+    }
+  }
+  return rc;
+}
+
+static int sqlite3Fts5StorageRowCount(Fts5Storage *p, i64 *pnRow){
+  int rc = fts5StorageLoadTotals(p, 0);
+  if( rc==SQLITE_OK ){
+    /* nTotalRow being zero does not necessarily indicate a corrupt
+    ** database - it might be that the FTS5 table really does contain zero
+    ** rows. However this function is only called from the xRowCount() API,
+    ** and there is no way for that API to be invoked if the table contains
+    ** no rows. Hence the FTS5_CORRUPT return.  */
+    *pnRow = p->nTotalRow;
+    if( p->nTotalRow<=0 ) rc = FTS5_CORRUPT;
+  }
+  return rc;
+}
+
+/*
+** Flush any data currently held in-memory to disk.
+*/
+static int sqlite3Fts5StorageSync(Fts5Storage *p){
+  int rc = SQLITE_OK;
+  i64 iLastRowid = sqlite3_last_insert_rowid(p->pConfig->db);
+  if( p->bTotalsValid ){
+    rc = fts5StorageSaveTotals(p);
+    if( rc==SQLITE_OK ){
+      p->bTotalsValid = 0;
+    }
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexSync(p->pIndex);
+  }
+  sqlite3_set_last_insert_rowid(p->pConfig->db, iLastRowid);
+  return rc;
+}
+
+static int sqlite3Fts5StorageRollback(Fts5Storage *p){
+  p->bTotalsValid = 0;
+  return sqlite3Fts5IndexRollback(p->pIndex);
+}
+
+static int sqlite3Fts5StorageConfigValue(
+  Fts5Storage *p,
+  const char *z,
+  sqlite3_value *pVal,
+  int iVal
+){
+  sqlite3_stmt *pReplace = 0;
+  int rc = fts5StorageGetStmt(p, FTS5_STMT_REPLACE_CONFIG, &pReplace, 0);
+  if( rc==SQLITE_OK ){
+    sqlite3_bind_text(pReplace, 1, z, -1, SQLITE_STATIC);
+    if( pVal ){
+      sqlite3_bind_value(pReplace, 2, pVal);
+    }else{
+      sqlite3_bind_int(pReplace, 2, iVal);
+    }
+    sqlite3_step(pReplace);
+    rc = sqlite3_reset(pReplace);
+    sqlite3_bind_null(pReplace, 1);
+  }
+  if( rc==SQLITE_OK && pVal ){
+    int iNew = p->pConfig->iCookie + 1;
+    rc = sqlite3Fts5IndexSetCookie(p->pIndex, iNew);
+    if( rc==SQLITE_OK ){
+      p->pConfig->iCookie = iNew;
+    }
+  }
+  return rc;
+}
+
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+
+/* #include "fts5Int.h" */
+
+/**************************************************************************
+** Start of ascii tokenizer implementation.
+*/
+
+/*
+** For tokenizers with no "unicode" modifier, the set of token characters
+** is the same as the set of ASCII range alphanumeric characters.
+*/
+static unsigned char aAsciiTokenChar[128] = {
+  0, 0, 0, 0, 0, 0, 0, 0,   0, 0, 0, 0, 0, 0, 0, 0,   /* 0x00..0x0F */
+  0, 0, 0, 0, 0, 0, 0, 0,   0, 0, 0, 0, 0, 0, 0, 0,   /* 0x10..0x1F */
+  0, 0, 0, 0, 0, 0, 0, 0,   0, 0, 0, 0, 0, 0, 0, 0,   /* 0x20..0x2F */
+  1, 1, 1, 1, 1, 1, 1, 1,   1, 1, 0, 0, 0, 0, 0, 0,   /* 0x30..0x3F */
+  0, 1, 1, 1, 1, 1, 1, 1,   1, 1, 1, 1, 1, 1, 1, 1,   /* 0x40..0x4F */
+  1, 1, 1, 1, 1, 1, 1, 1,   1, 1, 1, 0, 0, 0, 0, 0,   /* 0x50..0x5F */
+  0, 1, 1, 1, 1, 1, 1, 1,   1, 1, 1, 1, 1, 1, 1, 1,   /* 0x60..0x6F */
+  1, 1, 1, 1, 1, 1, 1, 1,   1, 1, 1, 0, 0, 0, 0, 0,   /* 0x70..0x7F */
+};
+
+typedef struct AsciiTokenizer AsciiTokenizer;
+struct AsciiTokenizer {
+  unsigned char aTokenChar[128];
+};
+
+static void fts5AsciiAddExceptions(
+  AsciiTokenizer *p,
+  const char *zArg,
+  int bTokenChars
+){
+  int i;
+  for(i=0; zArg[i]; i++){
+    if( (zArg[i] & 0x80)==0 ){
+      p->aTokenChar[(int)zArg[i]] = (unsigned char)bTokenChars;
+    }
+  }
+}
+
+/*
+** Delete a "ascii" tokenizer.
+*/
+static void fts5AsciiDelete(Fts5Tokenizer *p){
+  sqlite3_free(p);
+}
+
+/*
+** Create an "ascii" tokenizer.
+*/
+static int fts5AsciiCreate(
+  void *pUnused,
+  const char **azArg, int nArg,
+  Fts5Tokenizer **ppOut
+){
+  int rc = SQLITE_OK;
+  AsciiTokenizer *p = 0;
+  UNUSED_PARAM(pUnused);
+  if( nArg%2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    p = sqlite3_malloc(sizeof(AsciiTokenizer));
+    if( p==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      int i;
+      memset(p, 0, sizeof(AsciiTokenizer));
+      memcpy(p->aTokenChar, aAsciiTokenChar, sizeof(aAsciiTokenChar));
+      for(i=0; rc==SQLITE_OK && i<nArg; i+=2){
+        const char *zArg = azArg[i+1];
+        if( 0==sqlite3_stricmp(azArg[i], "tokenchars") ){
+          fts5AsciiAddExceptions(p, zArg, 1);
+        }else
+        if( 0==sqlite3_stricmp(azArg[i], "separators") ){
+          fts5AsciiAddExceptions(p, zArg, 0);
+        }else{
+          rc = SQLITE_ERROR;
+        }
+      }
+      if( rc!=SQLITE_OK ){
+        fts5AsciiDelete((Fts5Tokenizer*)p);
+        p = 0;
+      }
+    }
+  }
+
+  *ppOut = (Fts5Tokenizer*)p;
+  return rc;
+}
+
+
+static void asciiFold(char *aOut, const char *aIn, int nByte){
+  int i;
+  for(i=0; i<nByte; i++){
+    char c = aIn[i];
+    if( c>='A' && c<='Z' ) c += 32;
+    aOut[i] = c;
+  }
+}
+
+/*
+** Tokenize some text using the ascii tokenizer.
+*/
+static int fts5AsciiTokenize(
+  Fts5Tokenizer *pTokenizer,
+  void *pCtx,
+  int iUnused,
+  const char *pText, int nText,
+  int (*xToken)(void*, int, const char*, int nToken, int iStart, int iEnd)
+){
+  AsciiTokenizer *p = (AsciiTokenizer*)pTokenizer;
+  int rc = SQLITE_OK;
+  int ie;
+  int is = 0;
+
+  char aFold[64];
+  int nFold = sizeof(aFold);
+  char *pFold = aFold;
+  unsigned char *a = p->aTokenChar;
+
+  UNUSED_PARAM(iUnused);
+
+  while( is<nText && rc==SQLITE_OK ){
+    int nByte;
+
+    /* Skip any leading divider characters. */
+    while( is<nText && ((pText[is]&0x80)==0 && a[(int)pText[is]]==0) ){
+      is++;
+    }
+    if( is==nText ) break;
+
+    /* Count the token characters */
+    ie = is+1;
+    while( ie<nText && ((pText[ie]&0x80) || a[(int)pText[ie]] ) ){
+      ie++;
+    }
+
+    /* Fold to lower case */
+    nByte = ie-is;
+    if( nByte>nFold ){
+      if( pFold!=aFold ) sqlite3_free(pFold);
+      pFold = sqlite3_malloc64((sqlite3_int64)nByte*2);
+      if( pFold==0 ){
+        rc = SQLITE_NOMEM;
+        break;
+      }
+      nFold = nByte*2;
+    }
+    asciiFold(pFold, &pText[is], nByte);
+
+    /* Invoke the token callback */
+    rc = xToken(pCtx, 0, pFold, nByte, is, ie);
+    is = ie+1;
+  }
+
+  if( pFold!=aFold ) sqlite3_free(pFold);
+  if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  return rc;
+}
+
+/**************************************************************************
+** Start of unicode61 tokenizer implementation.
+*/
+
+
+/*
+** The following two macros - READ_UTF8 and WRITE_UTF8 - have been copied
+** from the sqlite3 source file utf.c. If this file is compiled as part
+** of the amalgamation, they are not required.
+*/
+#ifndef SQLITE_AMALGAMATION
+
+static const unsigned char sqlite3Utf8Trans1[] = {
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
+};
+
+#define READ_UTF8(zIn, zTerm, c)                           \
+  c = *(zIn++);                                            \
+  if( c>=0xc0 ){                                           \
+    c = sqlite3Utf8Trans1[c-0xc0];                         \
+    while( zIn<zTerm && (*zIn & 0xc0)==0x80 ){             \
+      c = (c<<6) + (0x3f & *(zIn++));                      \
+    }                                                      \
+    if( c<0x80                                             \
+        || (c&0xFFFFF800)==0xD800                          \
+        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }        \
+  }
+
+
+#define WRITE_UTF8(zOut, c) {                          \
+  if( c<0x00080 ){                                     \
+    *zOut++ = (unsigned char)(c&0xFF);                 \
+  }                                                    \
+  else if( c<0x00800 ){                                \
+    *zOut++ = 0xC0 + (unsigned char)((c>>6)&0x1F);     \
+    *zOut++ = 0x80 + (unsigned char)(c & 0x3F);        \
+  }                                                    \
+  else if( c<0x10000 ){                                \
+    *zOut++ = 0xE0 + (unsigned char)((c>>12)&0x0F);    \
+    *zOut++ = 0x80 + (unsigned char)((c>>6) & 0x3F);   \
+    *zOut++ = 0x80 + (unsigned char)(c & 0x3F);        \
+  }else{                                               \
+    *zOut++ = 0xF0 + (unsigned char)((c>>18) & 0x07);  \
+    *zOut++ = 0x80 + (unsigned char)((c>>12) & 0x3F);  \
+    *zOut++ = 0x80 + (unsigned char)((c>>6) & 0x3F);   \
+    *zOut++ = 0x80 + (unsigned char)(c & 0x3F);        \
+  }                                                    \
+}
+
+#endif /* ifndef SQLITE_AMALGAMATION */
+
+#define FTS5_SKIP_UTF8(zIn) {                               \
+  if( ((unsigned char)(*(zIn++)))>=0xc0 ){                              \
+    while( (((unsigned char)*zIn) & 0xc0)==0x80 ){ zIn++; }             \
+  }                                                    \
+}
+
+typedef struct Unicode61Tokenizer Unicode61Tokenizer;
+struct Unicode61Tokenizer {
+  unsigned char aTokenChar[128];  /* ASCII range token characters */
+  char *aFold;                    /* Buffer to fold text into */
+  int nFold;                      /* Size of aFold[] in bytes */
+  int eRemoveDiacritic;           /* True if remove_diacritics=1 is set */
+  int nException;
+  int *aiException;
+
+  unsigned char aCategory[32];    /* True for token char categories */
+};
+
+/* Values for eRemoveDiacritic (must match internals of fts5_unicode2.c) */
+#define FTS5_REMOVE_DIACRITICS_NONE    0
+#define FTS5_REMOVE_DIACRITICS_SIMPLE  1
+#define FTS5_REMOVE_DIACRITICS_COMPLEX 2
+
+static int fts5UnicodeAddExceptions(
+  Unicode61Tokenizer *p,          /* Tokenizer object */
+  const char *z,                  /* Characters to treat as exceptions */
+  int bTokenChars                 /* 1 for 'tokenchars', 0 for 'separators' */
+){
+  int rc = SQLITE_OK;
+  int n = (int)strlen(z);
+  int *aNew;
+
+  if( n>0 ){
+    aNew = (int*)sqlite3_realloc64(p->aiException,
+                                   (n+p->nException)*sizeof(int));
+    if( aNew ){
+      int nNew = p->nException;
+      const unsigned char *zCsr = (const unsigned char*)z;
+      const unsigned char *zTerm = (const unsigned char*)&z[n];
+      while( zCsr<zTerm ){
+        u32 iCode;
+        int bToken;
+        READ_UTF8(zCsr, zTerm, iCode);
+        if( iCode<128 ){
+          p->aTokenChar[iCode] = (unsigned char)bTokenChars;
+        }else{
+          bToken = p->aCategory[sqlite3Fts5UnicodeCategory(iCode)];
+          assert( (bToken==0 || bToken==1) );
+          assert( (bTokenChars==0 || bTokenChars==1) );
+          if( bToken!=bTokenChars && sqlite3Fts5UnicodeIsdiacritic(iCode)==0 ){
+            int i;
+            for(i=0; i<nNew; i++){
+              if( (u32)aNew[i]>iCode ) break;
+            }
+            memmove(&aNew[i+1], &aNew[i], (nNew-i)*sizeof(int));
+            aNew[i] = iCode;
+            nNew++;
+          }
+        }
+      }
+      p->aiException = aNew;
+      p->nException = nNew;
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Return true if the p->aiException[] array contains the value iCode.
+*/
+static int fts5UnicodeIsException(Unicode61Tokenizer *p, int iCode){
+  if( p->nException>0 ){
+    int *a = p->aiException;
+    int iLo = 0;
+    int iHi = p->nException-1;
+
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      if( iCode==a[iTest] ){
+        return 1;
+      }else if( iCode>a[iTest] ){
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+  }
+
+  return 0;
+}
+
+/*
+** Delete a "unicode61" tokenizer.
+*/
+static void fts5UnicodeDelete(Fts5Tokenizer *pTok){
+  if( pTok ){
+    Unicode61Tokenizer *p = (Unicode61Tokenizer*)pTok;
+    sqlite3_free(p->aiException);
+    sqlite3_free(p->aFold);
+    sqlite3_free(p);
+  }
+  return;
+}
+
+static int unicodeSetCategories(Unicode61Tokenizer *p, const char *zCat){
+  const char *z = zCat;
+
+  while( *z ){
+    while( *z==' ' || *z=='\t' ) z++;
+    if( *z && sqlite3Fts5UnicodeCatParse(z, p->aCategory) ){
+      return SQLITE_ERROR;
+    }
+    while( *z!=' ' && *z!='\t' && *z!='\0' ) z++;
+  }
+
+  sqlite3Fts5UnicodeAscii(p->aCategory, p->aTokenChar);
+  return SQLITE_OK;
+}
+
+/*
+** Create a "unicode61" tokenizer.
+*/
+static int fts5UnicodeCreate(
+  void *pUnused,
+  const char **azArg, int nArg,
+  Fts5Tokenizer **ppOut
+){
+  int rc = SQLITE_OK;             /* Return code */
+  Unicode61Tokenizer *p = 0;      /* New tokenizer object */
+
+  UNUSED_PARAM(pUnused);
+
+  if( nArg%2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    p = (Unicode61Tokenizer*)sqlite3_malloc(sizeof(Unicode61Tokenizer));
+    if( p ){
+      const char *zCat = "L* N* Co";
+      int i;
+      memset(p, 0, sizeof(Unicode61Tokenizer));
+
+      p->eRemoveDiacritic = FTS5_REMOVE_DIACRITICS_SIMPLE;
+      p->nFold = 64;
+      p->aFold = sqlite3_malloc64(p->nFold * sizeof(char));
+      if( p->aFold==0 ){
+        rc = SQLITE_NOMEM;
+      }
+
+      /* Search for a "categories" argument */
+      for(i=0; rc==SQLITE_OK && i<nArg; i+=2){
+        if( 0==sqlite3_stricmp(azArg[i], "categories") ){
+          zCat = azArg[i+1];
+        }
+      }
+      if( rc==SQLITE_OK ){
+        rc = unicodeSetCategories(p, zCat);
+      }
+
+      for(i=0; rc==SQLITE_OK && i<nArg; i+=2){
+        const char *zArg = azArg[i+1];
+        if( 0==sqlite3_stricmp(azArg[i], "remove_diacritics") ){
+          if( (zArg[0]!='0' && zArg[0]!='1' && zArg[0]!='2') || zArg[1] ){
+            rc = SQLITE_ERROR;
+          }else{
+            p->eRemoveDiacritic = (zArg[0] - '0');
+            assert( p->eRemoveDiacritic==FTS5_REMOVE_DIACRITICS_NONE
+                 || p->eRemoveDiacritic==FTS5_REMOVE_DIACRITICS_SIMPLE
+                 || p->eRemoveDiacritic==FTS5_REMOVE_DIACRITICS_COMPLEX
+            );
+          }
+        }else
+        if( 0==sqlite3_stricmp(azArg[i], "tokenchars") ){
+          rc = fts5UnicodeAddExceptions(p, zArg, 1);
+        }else
+        if( 0==sqlite3_stricmp(azArg[i], "separators") ){
+          rc = fts5UnicodeAddExceptions(p, zArg, 0);
+        }else
+        if( 0==sqlite3_stricmp(azArg[i], "categories") ){
+          /* no-op */
+        }else{
+          rc = SQLITE_ERROR;
+        }
+      }
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+    if( rc!=SQLITE_OK ){
+      fts5UnicodeDelete((Fts5Tokenizer*)p);
+      p = 0;
+    }
+    *ppOut = (Fts5Tokenizer*)p;
+  }
+  return rc;
+}
+
+/*
+** Return true if, for the purposes of tokenizing with the tokenizer
+** passed as the first argument, codepoint iCode is considered a token
+** character (not a separator).
+*/
+static int fts5UnicodeIsAlnum(Unicode61Tokenizer *p, int iCode){
+  return (
+    p->aCategory[sqlite3Fts5UnicodeCategory((u32)iCode)]
+    ^ fts5UnicodeIsException(p, iCode)
+  );
+}
+
+static int fts5UnicodeTokenize(
+  Fts5Tokenizer *pTokenizer,
+  void *pCtx,
+  int iUnused,
+  const char *pText, int nText,
+  int (*xToken)(void*, int, const char*, int nToken, int iStart, int iEnd)
+){
+  Unicode61Tokenizer *p = (Unicode61Tokenizer*)pTokenizer;
+  int rc = SQLITE_OK;
+  unsigned char *a = p->aTokenChar;
+
+  unsigned char *zTerm = (unsigned char*)&pText[nText];
+  unsigned char *zCsr = (unsigned char *)pText;
+
+  /* Output buffer */
+  char *aFold = p->aFold;
+  int nFold = p->nFold;
+  const char *pEnd = &aFold[nFold-6];
+
+  UNUSED_PARAM(iUnused);
+
+  /* Each iteration of this loop gobbles up a contiguous run of separators,
+  ** then the next token.  */
+  while( rc==SQLITE_OK ){
+    u32 iCode;                    /* non-ASCII codepoint read from input */
+    char *zOut = aFold;
+    int is;
+    int ie;
+
+    /* Skip any separator characters. */
+    while( 1 ){
+      if( zCsr>=zTerm ) goto tokenize_done;
+      if( *zCsr & 0x80 ) {
+        /* A character outside of the ascii range. Skip past it if it is
+        ** a separator character. Or break out of the loop if it is not. */
+        is = zCsr - (unsigned char*)pText;
+        READ_UTF8(zCsr, zTerm, iCode);
+        if( fts5UnicodeIsAlnum(p, iCode) ){
+          goto non_ascii_tokenchar;
+        }
+      }else{
+        if( a[*zCsr] ){
+          is = zCsr - (unsigned char*)pText;
+          goto ascii_tokenchar;
+        }
+        zCsr++;
+      }
+    }
+
+    /* Run through the tokenchars. Fold them into the output buffer along
+    ** the way.  */
+    while( zCsr<zTerm ){
+
+      /* Grow the output buffer so that there is sufficient space to fit the
+      ** largest possible utf-8 character.  */
+      if( zOut>pEnd ){
+        aFold = sqlite3_malloc64((sqlite3_int64)nFold*2);
+        if( aFold==0 ){
+          rc = SQLITE_NOMEM;
+          goto tokenize_done;
+        }
+        zOut = &aFold[zOut - p->aFold];
+        memcpy(aFold, p->aFold, nFold);
+        sqlite3_free(p->aFold);
+        p->aFold = aFold;
+        p->nFold = nFold = nFold*2;
+        pEnd = &aFold[nFold-6];
+      }
+
+      if( *zCsr & 0x80 ){
+        /* An non-ascii-range character. Fold it into the output buffer if
+        ** it is a token character, or break out of the loop if it is not. */
+        READ_UTF8(zCsr, zTerm, iCode);
+        if( fts5UnicodeIsAlnum(p,iCode)||sqlite3Fts5UnicodeIsdiacritic(iCode) ){
+ non_ascii_tokenchar:
+          iCode = sqlite3Fts5UnicodeFold(iCode, p->eRemoveDiacritic);
+          if( iCode ) WRITE_UTF8(zOut, iCode);
+        }else{
+          break;
+        }
+      }else if( a[*zCsr]==0 ){
+        /* An ascii-range separator character. End of token. */
+        break;
+      }else{
+ ascii_tokenchar:
+        if( *zCsr>='A' && *zCsr<='Z' ){
+          *zOut++ = *zCsr + 32;
+        }else{
+          *zOut++ = *zCsr;
+        }
+        zCsr++;
+      }
+      ie = zCsr - (unsigned char*)pText;
+    }
+
+    /* Invoke the token callback */
+    rc = xToken(pCtx, 0, aFold, zOut-aFold, is, ie);
+  }
+
+ tokenize_done:
+  if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+  return rc;
+}
+
+/**************************************************************************
+** Start of porter stemmer implementation.
+*/
+
+/* Any tokens larger than this (in bytes) are passed through without
+** stemming. */
+#define FTS5_PORTER_MAX_TOKEN 64
+
+typedef struct PorterTokenizer PorterTokenizer;
+struct PorterTokenizer {
+  fts5_tokenizer_v2 tokenizer_v2; /* Parent tokenizer module */
+  Fts5Tokenizer *pTokenizer;      /* Parent tokenizer instance */
+  char aBuf[FTS5_PORTER_MAX_TOKEN + 64];
+};
+
+/*
+** Delete a "porter" tokenizer.
+*/
+static void fts5PorterDelete(Fts5Tokenizer *pTok){
+  if( pTok ){
+    PorterTokenizer *p = (PorterTokenizer*)pTok;
+    if( p->pTokenizer ){
+      p->tokenizer_v2.xDelete(p->pTokenizer);
+    }
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Create a "porter" tokenizer.
+*/
+static int fts5PorterCreate(
+  void *pCtx,
+  const char **azArg, int nArg,
+  Fts5Tokenizer **ppOut
+){
+  fts5_api *pApi = (fts5_api*)pCtx;
+  int rc = SQLITE_OK;
+  PorterTokenizer *pRet;
+  void *pUserdata = 0;
+  const char *zBase = "unicode61";
+  fts5_tokenizer_v2 *pV2 = 0;
+
+  if( nArg>0 ){
+    zBase = azArg[0];
+  }
+
+  pRet = (PorterTokenizer*)sqlite3_malloc(sizeof(PorterTokenizer));
+  if( pRet ){
+    memset(pRet, 0, sizeof(PorterTokenizer));
+    rc = pApi->xFindTokenizer_v2(pApi, zBase, &pUserdata, &pV2);
+  }else{
+    rc = SQLITE_NOMEM;
+  }
+  if( rc==SQLITE_OK ){
+    int nArg2 = (nArg>0 ? nArg-1 : 0);
+    const char **az2 = (nArg2 ? &azArg[1] : 0);
+    memcpy(&pRet->tokenizer_v2, pV2, sizeof(fts5_tokenizer_v2));
+    rc = pRet->tokenizer_v2.xCreate(pUserdata, az2, nArg2, &pRet->pTokenizer);
+  }
+
+  if( rc!=SQLITE_OK ){
+    fts5PorterDelete((Fts5Tokenizer*)pRet);
+    pRet = 0;
+  }
+  *ppOut = (Fts5Tokenizer*)pRet;
+  return rc;
+}
+
+typedef struct PorterContext PorterContext;
+struct PorterContext {
+  void *pCtx;
+  int (*xToken)(void*, int, const char*, int, int, int);
+  char *aBuf;
+};
+
+typedef struct PorterRule PorterRule;
+struct PorterRule {
+  const char *zSuffix;
+  int nSuffix;
+  int (*xCond)(char *zStem, int nStem);
+  const char *zOutput;
+  int nOutput;
+};
+
+#if 0
+static int fts5PorterApply(char *aBuf, int *pnBuf, PorterRule *aRule){
+  int ret = -1;
+  int nBuf = *pnBuf;
+  PorterRule *p;
+
+  for(p=aRule; p->zSuffix; p++){
+    assert( strlen(p->zSuffix)==p->nSuffix );
+    assert( strlen(p->zOutput)==p->nOutput );
+    if( nBuf<p->nSuffix ) continue;
+    if( 0==memcmp(&aBuf[nBuf - p->nSuffix], p->zSuffix, p->nSuffix) ) break;
+  }
+
+  if( p->zSuffix ){
+    int nStem = nBuf - p->nSuffix;
+    if( p->xCond==0 || p->xCond(aBuf, nStem) ){
+      memcpy(&aBuf[nStem], p->zOutput, p->nOutput);
+      *pnBuf = nStem + p->nOutput;
+      ret = p - aRule;
+    }
+  }
+
+  return ret;
+}
+#endif
+
+static int fts5PorterIsVowel(char c, int bYIsVowel){
+  return (
+      c=='a' || c=='e' || c=='i' || c=='o' || c=='u' || (bYIsVowel && c=='y')
+  );
+}
+
+static int fts5PorterGobbleVC(char *zStem, int nStem, int bPrevCons){
+  int i;
+  int bCons = bPrevCons;
+
+  /* Scan for a vowel */
+  for(i=0; i<nStem; i++){
+    if( 0==(bCons = !fts5PorterIsVowel(zStem[i], bCons)) ) break;
+  }
+
+  /* Scan for a consonent */
+  for(i++; i<nStem; i++){
+    if( (bCons = !fts5PorterIsVowel(zStem[i], bCons)) ) return i+1;
+  }
+  return 0;
+}
+
+/* porter rule condition: (m > 0) */
+static int fts5Porter_MGt0(char *zStem, int nStem){
+  return !!fts5PorterGobbleVC(zStem, nStem, 0);
+}
+
+/* porter rule condition: (m > 1) */
+static int fts5Porter_MGt1(char *zStem, int nStem){
+  int n;
+  n = fts5PorterGobbleVC(zStem, nStem, 0);
+  if( n && fts5PorterGobbleVC(&zStem[n], nStem-n, 1) ){
+    return 1;
+  }
+  return 0;
+}
+
+/* porter rule condition: (m = 1) */
+static int fts5Porter_MEq1(char *zStem, int nStem){
+  int n;
+  n = fts5PorterGobbleVC(zStem, nStem, 0);
+  if( n && 0==fts5PorterGobbleVC(&zStem[n], nStem-n, 1) ){
+    return 1;
+  }
+  return 0;
+}
+
+/* porter rule condition: (*o) */
+static int fts5Porter_Ostar(char *zStem, int nStem){
+  if( zStem[nStem-1]=='w' || zStem[nStem-1]=='x' || zStem[nStem-1]=='y' ){
+    return 0;
+  }else{
+    int i;
+    int mask = 0;
+    int bCons = 0;
+    for(i=0; i<nStem; i++){
+      bCons = !fts5PorterIsVowel(zStem[i], bCons);
+      assert( bCons==0 || bCons==1 );
+      mask = (mask << 1) + bCons;
+    }
+    return ((mask & 0x0007)==0x0005);
+  }
+}
+
+/* porter rule condition: (m > 1 and (*S or *T)) */
+static int fts5Porter_MGt1_and_S_or_T(char *zStem, int nStem){
+  assert( nStem>0 );
+  return (zStem[nStem-1]=='s' || zStem[nStem-1]=='t')
+      && fts5Porter_MGt1(zStem, nStem);
+}
+
+/* porter rule condition: (*v*) */
+static int fts5Porter_Vowel(char *zStem, int nStem){
+  int i;
+  for(i=0; i<nStem; i++){
+    if( fts5PorterIsVowel(zStem[i], i>0) ){
+      return 1;
+    }
+  }
+  return 0;
+}
+
+
+/**************************************************************************
+***************************************************************************
+** GENERATED CODE STARTS HERE (mkportersteps.tcl)
+*/
+
+static int fts5PorterStep4(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'a':
+      if( nBuf>2 && 0==memcmp("al", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+        }
+      }
+      break;
+
+    case 'c':
+      if( nBuf>4 && 0==memcmp("ance", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }else if( nBuf>4 && 0==memcmp("ence", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }
+      break;
+
+    case 'e':
+      if( nBuf>2 && 0==memcmp("er", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+        }
+      }
+      break;
+
+    case 'i':
+      if( nBuf>2 && 0==memcmp("ic", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+        }
+      }
+      break;
+
+    case 'l':
+      if( nBuf>4 && 0==memcmp("able", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }else if( nBuf>4 && 0==memcmp("ible", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }
+      break;
+
+    case 'n':
+      if( nBuf>3 && 0==memcmp("ant", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }else if( nBuf>5 && 0==memcmp("ement", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-5) ){
+          *pnBuf = nBuf - 5;
+        }
+      }else if( nBuf>4 && 0==memcmp("ment", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }else if( nBuf>3 && 0==memcmp("ent", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'o':
+      if( nBuf>3 && 0==memcmp("ion", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1_and_S_or_T(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }else if( nBuf>2 && 0==memcmp("ou", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+        }
+      }
+      break;
+
+    case 's':
+      if( nBuf>3 && 0==memcmp("ism", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 't':
+      if( nBuf>3 && 0==memcmp("ate", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }else if( nBuf>3 && 0==memcmp("iti", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'u':
+      if( nBuf>3 && 0==memcmp("ous", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'v':
+      if( nBuf>3 && 0==memcmp("ive", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'z':
+      if( nBuf>3 && 0==memcmp("ize", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt1(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+  }
+  return ret;
+}
+
+
+static int fts5PorterStep1B2(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'a':
+      if( nBuf>2 && 0==memcmp("at", &aBuf[nBuf-2], 2) ){
+        memcpy(&aBuf[nBuf-2], "ate", 3);
+        *pnBuf = nBuf - 2 + 3;
+        ret = 1;
+      }
+      break;
+
+    case 'b':
+      if( nBuf>2 && 0==memcmp("bl", &aBuf[nBuf-2], 2) ){
+        memcpy(&aBuf[nBuf-2], "ble", 3);
+        *pnBuf = nBuf - 2 + 3;
+        ret = 1;
+      }
+      break;
+
+    case 'i':
+      if( nBuf>2 && 0==memcmp("iz", &aBuf[nBuf-2], 2) ){
+        memcpy(&aBuf[nBuf-2], "ize", 3);
+        *pnBuf = nBuf - 2 + 3;
+        ret = 1;
+      }
+      break;
+
+  }
+  return ret;
+}
+
+
+static int fts5PorterStep2(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'a':
+      if( nBuf>7 && 0==memcmp("ational", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ate", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }else if( nBuf>6 && 0==memcmp("tional", &aBuf[nBuf-6], 6) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-6) ){
+          memcpy(&aBuf[nBuf-6], "tion", 4);
+          *pnBuf = nBuf - 6 + 4;
+        }
+      }
+      break;
+
+    case 'c':
+      if( nBuf>4 && 0==memcmp("enci", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ence", 4);
+          *pnBuf = nBuf - 4 + 4;
+        }
+      }else if( nBuf>4 && 0==memcmp("anci", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ance", 4);
+          *pnBuf = nBuf - 4 + 4;
+        }
+      }
+      break;
+
+    case 'e':
+      if( nBuf>4 && 0==memcmp("izer", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ize", 3);
+          *pnBuf = nBuf - 4 + 3;
+        }
+      }
+      break;
+
+    case 'g':
+      if( nBuf>4 && 0==memcmp("logi", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "log", 3);
+          *pnBuf = nBuf - 4 + 3;
+        }
+      }
+      break;
+
+    case 'l':
+      if( nBuf>3 && 0==memcmp("bli", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-3) ){
+          memcpy(&aBuf[nBuf-3], "ble", 3);
+          *pnBuf = nBuf - 3 + 3;
+        }
+      }else if( nBuf>4 && 0==memcmp("alli", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "al", 2);
+          *pnBuf = nBuf - 4 + 2;
+        }
+      }else if( nBuf>5 && 0==memcmp("entli", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ent", 3);
+          *pnBuf = nBuf - 5 + 3;
+        }
+      }else if( nBuf>3 && 0==memcmp("eli", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-3) ){
+          memcpy(&aBuf[nBuf-3], "e", 1);
+          *pnBuf = nBuf - 3 + 1;
+        }
+      }else if( nBuf>5 && 0==memcmp("ousli", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ous", 3);
+          *pnBuf = nBuf - 5 + 3;
+        }
+      }
+      break;
+
+    case 'o':
+      if( nBuf>7 && 0==memcmp("ization", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ize", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }else if( nBuf>5 && 0==memcmp("ation", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ate", 3);
+          *pnBuf = nBuf - 5 + 3;
+        }
+      }else if( nBuf>4 && 0==memcmp("ator", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ate", 3);
+          *pnBuf = nBuf - 4 + 3;
+        }
+      }
+      break;
+
+    case 's':
+      if( nBuf>5 && 0==memcmp("alism", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "al", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }else if( nBuf>7 && 0==memcmp("iveness", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ive", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }else if( nBuf>7 && 0==memcmp("fulness", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ful", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }else if( nBuf>7 && 0==memcmp("ousness", &aBuf[nBuf-7], 7) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-7) ){
+          memcpy(&aBuf[nBuf-7], "ous", 3);
+          *pnBuf = nBuf - 7 + 3;
+        }
+      }
+      break;
+
+    case 't':
+      if( nBuf>5 && 0==memcmp("aliti", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "al", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }else if( nBuf>5 && 0==memcmp("iviti", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ive", 3);
+          *pnBuf = nBuf - 5 + 3;
+        }
+      }else if( nBuf>6 && 0==memcmp("biliti", &aBuf[nBuf-6], 6) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-6) ){
+          memcpy(&aBuf[nBuf-6], "ble", 3);
+          *pnBuf = nBuf - 6 + 3;
+        }
+      }
+      break;
+
+  }
+  return ret;
+}
+
+
+static int fts5PorterStep3(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'a':
+      if( nBuf>4 && 0==memcmp("ical", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          memcpy(&aBuf[nBuf-4], "ic", 2);
+          *pnBuf = nBuf - 4 + 2;
+        }
+      }
+      break;
+
+    case 's':
+      if( nBuf>4 && 0==memcmp("ness", &aBuf[nBuf-4], 4) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-4) ){
+          *pnBuf = nBuf - 4;
+        }
+      }
+      break;
+
+    case 't':
+      if( nBuf>5 && 0==memcmp("icate", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ic", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }else if( nBuf>5 && 0==memcmp("iciti", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "ic", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }
+      break;
+
+    case 'u':
+      if( nBuf>3 && 0==memcmp("ful", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+        }
+      }
+      break;
+
+    case 'v':
+      if( nBuf>5 && 0==memcmp("ative", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          *pnBuf = nBuf - 5;
+        }
+      }
+      break;
+
+    case 'z':
+      if( nBuf>5 && 0==memcmp("alize", &aBuf[nBuf-5], 5) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-5) ){
+          memcpy(&aBuf[nBuf-5], "al", 2);
+          *pnBuf = nBuf - 5 + 2;
+        }
+      }
+      break;
+
+  }
+  return ret;
+}
+
+
+static int fts5PorterStep1B(char *aBuf, int *pnBuf){
+  int ret = 0;
+  int nBuf = *pnBuf;
+  switch( aBuf[nBuf-2] ){
+
+    case 'e':
+      if( nBuf>3 && 0==memcmp("eed", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_MGt0(aBuf, nBuf-3) ){
+          memcpy(&aBuf[nBuf-3], "ee", 2);
+          *pnBuf = nBuf - 3 + 2;
+        }
+      }else if( nBuf>2 && 0==memcmp("ed", &aBuf[nBuf-2], 2) ){
+        if( fts5Porter_Vowel(aBuf, nBuf-2) ){
+          *pnBuf = nBuf - 2;
+          ret = 1;
+        }
+      }
+      break;
+
+    case 'n':
+      if( nBuf>3 && 0==memcmp("ing", &aBuf[nBuf-3], 3) ){
+        if( fts5Porter_Vowel(aBuf, nBuf-3) ){
+          *pnBuf = nBuf - 3;
+          ret = 1;
+        }
+      }
+      break;
+
+  }
+  return ret;
+}
+
+/*
+** GENERATED CODE ENDS HERE (mkportersteps.tcl)
+***************************************************************************
+**************************************************************************/
+
+static void fts5PorterStep1A(char *aBuf, int *pnBuf){
+  int nBuf = *pnBuf;
+  if( aBuf[nBuf-1]=='s' ){
+    if( aBuf[nBuf-2]=='e' ){
+      if( (nBuf>4 && aBuf[nBuf-4]=='s' && aBuf[nBuf-3]=='s')
+       || (nBuf>3 && aBuf[nBuf-3]=='i' )
+      ){
+        *pnBuf = nBuf-2;
+      }else{
+        *pnBuf = nBuf-1;
+      }
+    }
+    else if( aBuf[nBuf-2]!='s' ){
+      *pnBuf = nBuf-1;
+    }
+  }
+}
+
+static int fts5PorterCb(
+  void *pCtx,
+  int tflags,
+  const char *pToken,
+  int nToken,
+  int iStart,
+  int iEnd
+){
+  PorterContext *p = (PorterContext*)pCtx;
+
+  char *aBuf;
+  int nBuf;
+
+  if( nToken>FTS5_PORTER_MAX_TOKEN || nToken<3 ) goto pass_through;
+  aBuf = p->aBuf;
+  nBuf = nToken;
+  memcpy(aBuf, pToken, nBuf);
+
+  /* Step 1. */
+  fts5PorterStep1A(aBuf, &nBuf);
+  if( fts5PorterStep1B(aBuf, &nBuf) ){
+    if( fts5PorterStep1B2(aBuf, &nBuf)==0 ){
+      char c = aBuf[nBuf-1];
+      if( fts5PorterIsVowel(c, 0)==0
+       && c!='l' && c!='s' && c!='z' && c==aBuf[nBuf-2]
+      ){
+        nBuf--;
+      }else if( fts5Porter_MEq1(aBuf, nBuf) && fts5Porter_Ostar(aBuf, nBuf) ){
+        aBuf[nBuf++] = 'e';
+      }
+    }
+  }
+
+  /* Step 1C. */
+  if( aBuf[nBuf-1]=='y' && fts5Porter_Vowel(aBuf, nBuf-1) ){
+    aBuf[nBuf-1] = 'i';
+  }
+
+  /* Steps 2 through 4. */
+  fts5PorterStep2(aBuf, &nBuf);
+  fts5PorterStep3(aBuf, &nBuf);
+  fts5PorterStep4(aBuf, &nBuf);
+
+  /* Step 5a. */
+  assert( nBuf>0 );
+  if( aBuf[nBuf-1]=='e' ){
+    if( fts5Porter_MGt1(aBuf, nBuf-1)
+     || (fts5Porter_MEq1(aBuf, nBuf-1) && !fts5Porter_Ostar(aBuf, nBuf-1))
+    ){
+      nBuf--;
+    }
+  }
+
+  /* Step 5b. */
+  if( nBuf>1 && aBuf[nBuf-1]=='l'
+   && aBuf[nBuf-2]=='l' && fts5Porter_MGt1(aBuf, nBuf-1)
+  ){
+    nBuf--;
+  }
+
+  return p->xToken(p->pCtx, tflags, aBuf, nBuf, iStart, iEnd);
+
+ pass_through:
+  return p->xToken(p->pCtx, tflags, pToken, nToken, iStart, iEnd);
+}
+
+/*
+** Tokenize using the porter tokenizer.
+*/
+static int fts5PorterTokenize(
+  Fts5Tokenizer *pTokenizer,
+  void *pCtx,
+  int flags,
+  const char *pText, int nText,
+  const char *pLoc, int nLoc,
+  int (*xToken)(void*, int, const char*, int nToken, int iStart, int iEnd)
+){
+  PorterTokenizer *p = (PorterTokenizer*)pTokenizer;
+  PorterContext sCtx;
+  sCtx.xToken = xToken;
+  sCtx.pCtx = pCtx;
+  sCtx.aBuf = p->aBuf;
+  return p->tokenizer_v2.xTokenize(
+      p->pTokenizer, (void*)&sCtx, flags, pText, nText, pLoc, nLoc, fts5PorterCb
+  );
+}
+
+/**************************************************************************
+** Start of trigram implementation.
+*/
+typedef struct TrigramTokenizer TrigramTokenizer;
+struct TrigramTokenizer {
+  int bFold;                      /* True to fold to lower-case */
+  int iFoldParam;                 /* Parameter to pass to Fts5UnicodeFold() */
+};
+
+/*
+** Free a trigram tokenizer.
+*/
+static void fts5TriDelete(Fts5Tokenizer *p){
+  sqlite3_free(p);
+}
+
+/*
+** Allocate a trigram tokenizer.
+*/
+static int fts5TriCreate(
+  void *pUnused,
+  const char **azArg,
+  int nArg,
+  Fts5Tokenizer **ppOut
+){
+  int rc = SQLITE_OK;
+  TrigramTokenizer *pNew = 0;
+  UNUSED_PARAM(pUnused);
+  if( nArg%2 ){
+    rc = SQLITE_ERROR;
+  }else{
+    int i;
+    pNew = (TrigramTokenizer*)sqlite3_malloc(sizeof(*pNew));
+    if( pNew==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      pNew->bFold = 1;
+      pNew->iFoldParam = 0;
+
+      for(i=0; rc==SQLITE_OK && i<nArg; i+=2){
+        const char *zArg = azArg[i+1];
+        if( 0==sqlite3_stricmp(azArg[i], "case_sensitive") ){
+          if( (zArg[0]!='0' && zArg[0]!='1') || zArg[1] ){
+            rc = SQLITE_ERROR;
+          }else{
+            pNew->bFold = (zArg[0]=='0');
+          }
+        }else if( 0==sqlite3_stricmp(azArg[i], "remove_diacritics") ){
+          if( (zArg[0]!='0' && zArg[0]!='1' && zArg[0]!='2') || zArg[1] ){
+            rc = SQLITE_ERROR;
+          }else{
+            pNew->iFoldParam = (zArg[0]!='0') ? 2 : 0;
+          }
+        }else{
+          rc = SQLITE_ERROR;
+        }
+      }
+
+      if( pNew->iFoldParam!=0 && pNew->bFold==0 ){
+        rc = SQLITE_ERROR;
+      }
+
+      if( rc!=SQLITE_OK ){
+        fts5TriDelete((Fts5Tokenizer*)pNew);
+        pNew = 0;
+      }
+    }
+  }
+  *ppOut = (Fts5Tokenizer*)pNew;
+  return rc;
+}
+
+/*
+** Trigram tokenizer tokenize routine.
+*/
+static int fts5TriTokenize(
+  Fts5Tokenizer *pTok,
+  void *pCtx,
+  int unusedFlags,
+  const char *pText, int nText,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  TrigramTokenizer *p = (TrigramTokenizer*)pTok;
+  int rc = SQLITE_OK;
+  char aBuf[32];
+  char *zOut = aBuf;
+  int ii;
+  const unsigned char *zIn = (const unsigned char*)pText;
+  const unsigned char *zEof = (zIn ? &zIn[nText] : 0);
+  u32 iCode = 0;
+  int aStart[3];                  /* Input offset of each character in aBuf[] */
+
+  UNUSED_PARAM(unusedFlags);
+
+  /* Populate aBuf[] with the characters for the first trigram. */
+  for(ii=0; ii<3; ii++){
+    do {
+      aStart[ii] = zIn - (const unsigned char*)pText;
+      if( zIn>=zEof ) return SQLITE_OK;
+      READ_UTF8(zIn, zEof, iCode);
+      if( p->bFold ) iCode = sqlite3Fts5UnicodeFold(iCode, p->iFoldParam);
+    }while( iCode==0 );
+    WRITE_UTF8(zOut, iCode);
+  }
+
+  /* At the start of each iteration of this loop:
+  **
+  **  aBuf:      Contains 3 characters. The 3 characters of the next trigram.
+  **  zOut:      Points to the byte following the last character in aBuf.
+  **  aStart[3]: Contains the byte offset in the input text corresponding
+  **             to the start of each of the three characters in the buffer.
+  */
+  assert( zIn<=zEof );
+  while( 1 ){
+    int iNext;                    /* Start of character following current tri */
+    const char *z1;
+
+    /* Read characters from the input up until the first non-diacritic */
+    do {
+      iNext = zIn - (const unsigned char*)pText;
+      if( zIn>=zEof ){
+        iCode = 0;
+        break;
+      }
+      READ_UTF8(zIn, zEof, iCode);
+      if( p->bFold ) iCode = sqlite3Fts5UnicodeFold(iCode, p->iFoldParam);
+    }while( iCode==0 );
+
+    /* Pass the current trigram back to fts5 */
+    rc = xToken(pCtx, 0, aBuf, zOut-aBuf, aStart[0], iNext);
+    if( iCode==0 || rc!=SQLITE_OK ) break;
+
+    /* Remove the first character from buffer aBuf[]. Append the character
+    ** with codepoint iCode.  */
+    z1 = aBuf;
+    FTS5_SKIP_UTF8(z1);
+    memmove(aBuf, z1, zOut - z1);
+    zOut -= (z1 - aBuf);
+    WRITE_UTF8(zOut, iCode);
+
+    /* Update the aStart[] array */
+    aStart[0] = aStart[1];
+    aStart[1] = aStart[2];
+    aStart[2] = iNext;
+  }
+
+  return rc;
+}
+
+/*
+** Argument xCreate is a pointer to a constructor function for a tokenizer.
+** pTok is a tokenizer previously created using the same method. This function
+** returns one of FTS5_PATTERN_NONE, FTS5_PATTERN_LIKE or FTS5_PATTERN_GLOB
+** indicating the style of pattern matching that the tokenizer can support.
+** In practice, this is:
+**
+**     "trigram" tokenizer, case_sensitive=1 - FTS5_PATTERN_GLOB
+**     "trigram" tokenizer, case_sensitive=0 (the default) - FTS5_PATTERN_LIKE
+**     all other tokenizers - FTS5_PATTERN_NONE
+*/
+static int sqlite3Fts5TokenizerPattern(
+    int (*xCreate)(void*, const char**, int, Fts5Tokenizer**),
+    Fts5Tokenizer *pTok
+){
+  if( xCreate==fts5TriCreate ){
+    TrigramTokenizer *p = (TrigramTokenizer*)pTok;
+    if( p->iFoldParam==0 ){
+      return p->bFold ? FTS5_PATTERN_LIKE : FTS5_PATTERN_GLOB;
+    }
+  }
+  return FTS5_PATTERN_NONE;
+}
+
+/*
+** Return true if the tokenizer described by p->azArg[] is the trigram
+** tokenizer. This tokenizer needs to be loaded before xBestIndex is
+** called for the first time in order to correctly handle LIKE/GLOB.
+*/
+static int sqlite3Fts5TokenizerPreload(Fts5TokenizerConfig *p){
+  return (p->nArg>=1 && 0==sqlite3_stricmp(p->azArg[0], "trigram"));
+}
+
+
+/*
+** Register all built-in tokenizers with FTS5.
+*/
+static int sqlite3Fts5TokenizerInit(fts5_api *pApi){
+  struct BuiltinTokenizer {
+    const char *zName;
+    fts5_tokenizer x;
+  } aBuiltin[] = {
+    { "unicode61", {fts5UnicodeCreate, fts5UnicodeDelete, fts5UnicodeTokenize}},
+    { "ascii",     {fts5AsciiCreate, fts5AsciiDelete, fts5AsciiTokenize }},
+    { "trigram",   {fts5TriCreate, fts5TriDelete, fts5TriTokenize}},
+  };
+
+  int rc = SQLITE_OK;             /* Return code */
+  int i;                          /* To iterate through builtin functions */
+
+  for(i=0; rc==SQLITE_OK && i<ArraySize(aBuiltin); i++){
+    rc = pApi->xCreateTokenizer(pApi,
+        aBuiltin[i].zName,
+        (void*)pApi,
+        &aBuiltin[i].x,
+        0
+    );
+  }
+  if( rc==SQLITE_OK ){
+    fts5_tokenizer_v2 sPorter = {
+      2,
+      fts5PorterCreate,
+      fts5PorterDelete,
+      fts5PorterTokenize
+    };
+    rc = pApi->xCreateTokenizer_v2(pApi,
+        "porter",
+        (void*)pApi,
+        &sPorter,
+        0
+    );
+  }
+  return rc;
+}
+
+/*
+** 2012-05-25
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+*/
+
+/*
+** DO NOT EDIT THIS MACHINE GENERATED FILE.
+*/
+
+
+/* #include <assert.h> */
+
+
+
+/*
+** If the argument is a codepoint corresponding to a lowercase letter
+** in the ASCII range with a diacritic added, return the codepoint
+** of the ASCII letter only. For example, if passed 235 - "LATIN
+** SMALL LETTER E WITH DIAERESIS" - return 65 ("LATIN SMALL LETTER
+** E"). The resuls of passing a codepoint that corresponds to an
+** uppercase letter are undefined.
+*/
+static int fts5_remove_diacritic(int c, int bComplex){
+  unsigned short aDia[] = {
+        0,  1797,  1848,  1859,  1891,  1928,  1940,  1995,
+     2024,  2040,  2060,  2110,  2168,  2206,  2264,  2286,
+     2344,  2383,  2472,  2488,  2516,  2596,  2668,  2732,
+     2782,  2842,  2894,  2954,  2984,  3000,  3028,  3336,
+     3456,  3696,  3712,  3728,  3744,  3766,  3832,  3896,
+     3912,  3928,  3944,  3968,  4008,  4040,  4056,  4106,
+     4138,  4170,  4202,  4234,  4266,  4296,  4312,  4344,
+     4408,  4424,  4442,  4472,  4488,  4504,  6148,  6198,
+     6264,  6280,  6360,  6429,  6505,  6529, 61448, 61468,
+    61512, 61534, 61592, 61610, 61642, 61672, 61688, 61704,
+    61726, 61784, 61800, 61816, 61836, 61880, 61896, 61914,
+    61948, 61998, 62062, 62122, 62154, 62184, 62200, 62218,
+    62252, 62302, 62364, 62410, 62442, 62478, 62536, 62554,
+    62584, 62604, 62640, 62648, 62656, 62664, 62730, 62766,
+    62830, 62890, 62924, 62974, 63032, 63050, 63082, 63118,
+    63182, 63242, 63274, 63310, 63368, 63390,
+  };
+#define HIBIT ((unsigned char)0x80)
+  unsigned char aChar[] = {
+    '\0',      'a',       'c',       'e',       'i',       'n',
+    'o',       'u',       'y',       'y',       'a',       'c',
+    'd',       'e',       'e',       'g',       'h',       'i',
+    'j',       'k',       'l',       'n',       'o',       'r',
+    's',       't',       'u',       'u',       'w',       'y',
+    'z',       'o',       'u',       'a',       'i',       'o',
+    'u',       'u'|HIBIT, 'a'|HIBIT, 'g',       'k',       'o',
+    'o'|HIBIT, 'j',       'g',       'n',       'a'|HIBIT, 'a',
+    'e',       'i',       'o',       'r',       'u',       's',
+    't',       'h',       'a',       'e',       'o'|HIBIT, 'o',
+    'o'|HIBIT, 'y',       '\0',      '\0',      '\0',      '\0',
+    '\0',      '\0',      '\0',      '\0',      'a',       'b',
+    'c'|HIBIT, 'd',       'd',       'e'|HIBIT, 'e',       'e'|HIBIT,
+    'f',       'g',       'h',       'h',       'i',       'i'|HIBIT,
+    'k',       'l',       'l'|HIBIT, 'l',       'm',       'n',
+    'o'|HIBIT, 'p',       'r',       'r'|HIBIT, 'r',       's',
+    's'|HIBIT, 't',       'u',       'u'|HIBIT, 'v',       'w',
+    'w',       'x',       'y',       'z',       'h',       't',
+    'w',       'y',       'a',       'a'|HIBIT, 'a'|HIBIT, 'a'|HIBIT,
+    'e',       'e'|HIBIT, 'e'|HIBIT, 'i',       'o',       'o'|HIBIT,
+    'o'|HIBIT, 'o'|HIBIT, 'u',       'u'|HIBIT, 'u'|HIBIT, 'y',
+  };
+
+  unsigned int key = (((unsigned int)c)<<3) | 0x00000007;
+  int iRes = 0;
+  int iHi = sizeof(aDia)/sizeof(aDia[0]) - 1;
+  int iLo = 0;
+  while( iHi>=iLo ){
+    int iTest = (iHi + iLo) / 2;
+    if( key >= aDia[iTest] ){
+      iRes = iTest;
+      iLo = iTest+1;
+    }else{
+      iHi = iTest-1;
+    }
+  }
+  assert( key>=aDia[iRes] );
+  if( bComplex==0 && (aChar[iRes] & 0x80) ) return c;
+  return (c > (aDia[iRes]>>3) + (aDia[iRes]&0x07)) ? c : ((int)aChar[iRes] & 0x7F);
+}
+
+
+/*
+** Return true if the argument interpreted as a unicode codepoint
+** is a diacritical modifier character.
+*/
+static int sqlite3Fts5UnicodeIsdiacritic(int c){
+  unsigned int mask0 = 0x08029FDF;
+  unsigned int mask1 = 0x000361F8;
+  if( c<768 || c>817 ) return 0;
+  return (c < 768+32) ?
+      (mask0 & ((unsigned int)1 << (c-768))) :
+      (mask1 & ((unsigned int)1 << (c-768-32)));
+}
+
+
+/*
+** Interpret the argument as a unicode codepoint. If the codepoint
+** is an upper case character that has a lower case equivalent,
+** return the codepoint corresponding to the lower case version.
+** Otherwise, return a copy of the argument.
+**
+** The results are undefined if the value passed to this function
+** is less than zero.
+*/
+static int sqlite3Fts5UnicodeFold(int c, int eRemoveDiacritic){
+  /* Each entry in the following array defines a rule for folding a range
+  ** of codepoints to lower case. The rule applies to a range of nRange
+  ** codepoints starting at codepoint iCode.
+  **
+  ** If the least significant bit in flags is clear, then the rule applies
+  ** to all nRange codepoints (i.e. all nRange codepoints are upper case and
+  ** need to be folded). Or, if it is set, then the rule only applies to
+  ** every second codepoint in the range, starting with codepoint C.
+  **
+  ** The 7 most significant bits in flags are an index into the aiOff[]
+  ** array. If a specific codepoint C does require folding, then its lower
+  ** case equivalent is ((C + aiOff[flags>>1]) & 0xFFFF).
+  **
+  ** The contents of this array are generated by parsing the CaseFolding.txt
+  ** file distributed as part of the "Unicode Character Database". See
+  ** http://www.unicode.org for details.
+  */
+  static const struct TableEntry {
+    unsigned short iCode;
+    unsigned char flags;
+    unsigned char nRange;
+  } aEntry[] = {
+    {65, 14, 26},          {181, 64, 1},          {192, 14, 23},
+    {216, 14, 7},          {256, 1, 48},          {306, 1, 6},
+    {313, 1, 16},          {330, 1, 46},          {376, 116, 1},
+    {377, 1, 6},           {383, 104, 1},         {385, 50, 1},
+    {386, 1, 4},           {390, 44, 1},          {391, 0, 1},
+    {393, 42, 2},          {395, 0, 1},           {398, 32, 1},
+    {399, 38, 1},          {400, 40, 1},          {401, 0, 1},
+    {403, 42, 1},          {404, 46, 1},          {406, 52, 1},
+    {407, 48, 1},          {408, 0, 1},           {412, 52, 1},
+    {413, 54, 1},          {415, 56, 1},          {416, 1, 6},
+    {422, 60, 1},          {423, 0, 1},           {425, 60, 1},
+    {428, 0, 1},           {430, 60, 1},          {431, 0, 1},
+    {433, 58, 2},          {435, 1, 4},           {439, 62, 1},
+    {440, 0, 1},           {444, 0, 1},           {452, 2, 1},
+    {453, 0, 1},           {455, 2, 1},           {456, 0, 1},
+    {458, 2, 1},           {459, 1, 18},          {478, 1, 18},
+    {497, 2, 1},           {498, 1, 4},           {502, 122, 1},
+    {503, 134, 1},         {504, 1, 40},          {544, 110, 1},
+    {546, 1, 18},          {570, 70, 1},          {571, 0, 1},
+    {573, 108, 1},         {574, 68, 1},          {577, 0, 1},
+    {579, 106, 1},         {580, 28, 1},          {581, 30, 1},
+    {582, 1, 10},          {837, 36, 1},          {880, 1, 4},
+    {886, 0, 1},           {902, 18, 1},          {904, 16, 3},
+    {908, 26, 1},          {910, 24, 2},          {913, 14, 17},
+    {931, 14, 9},          {962, 0, 1},           {975, 4, 1},
+    {976, 140, 1},         {977, 142, 1},         {981, 146, 1},
+    {982, 144, 1},         {984, 1, 24},          {1008, 136, 1},
+    {1009, 138, 1},        {1012, 130, 1},        {1013, 128, 1},
+    {1015, 0, 1},          {1017, 152, 1},        {1018, 0, 1},
+    {1021, 110, 3},        {1024, 34, 16},        {1040, 14, 32},
+    {1120, 1, 34},         {1162, 1, 54},         {1216, 6, 1},
+    {1217, 1, 14},         {1232, 1, 88},         {1329, 22, 38},
+    {4256, 66, 38},        {4295, 66, 1},         {4301, 66, 1},
+    {7680, 1, 150},        {7835, 132, 1},        {7838, 96, 1},
+    {7840, 1, 96},         {7944, 150, 8},        {7960, 150, 6},
+    {7976, 150, 8},        {7992, 150, 8},        {8008, 150, 6},
+    {8025, 151, 8},        {8040, 150, 8},        {8072, 150, 8},
+    {8088, 150, 8},        {8104, 150, 8},        {8120, 150, 2},
+    {8122, 126, 2},        {8124, 148, 1},        {8126, 100, 1},
+    {8136, 124, 4},        {8140, 148, 1},        {8152, 150, 2},
+    {8154, 120, 2},        {8168, 150, 2},        {8170, 118, 2},
+    {8172, 152, 1},        {8184, 112, 2},        {8186, 114, 2},
+    {8188, 148, 1},        {8486, 98, 1},         {8490, 92, 1},
+    {8491, 94, 1},         {8498, 12, 1},         {8544, 8, 16},
+    {8579, 0, 1},          {9398, 10, 26},        {11264, 22, 47},
+    {11360, 0, 1},         {11362, 88, 1},        {11363, 102, 1},
+    {11364, 90, 1},        {11367, 1, 6},         {11373, 84, 1},
+    {11374, 86, 1},        {11375, 80, 1},        {11376, 82, 1},
+    {11378, 0, 1},         {11381, 0, 1},         {11390, 78, 2},
+    {11392, 1, 100},       {11499, 1, 4},         {11506, 0, 1},
+    {42560, 1, 46},        {42624, 1, 24},        {42786, 1, 14},
+    {42802, 1, 62},        {42873, 1, 4},         {42877, 76, 1},
+    {42878, 1, 10},        {42891, 0, 1},         {42893, 74, 1},
+    {42896, 1, 4},         {42912, 1, 10},        {42922, 72, 1},
+    {65313, 14, 26},
+  };
+  static const unsigned short aiOff[] = {
+   1,     2,     8,     15,    16,    26,    28,    32,
+   37,    38,    40,    48,    63,    64,    69,    71,
+   79,    80,    116,   202,   203,   205,   206,   207,
+   209,   210,   211,   213,   214,   217,   218,   219,
+   775,   7264,  10792, 10795, 23228, 23256, 30204, 54721,
+   54753, 54754, 54756, 54787, 54793, 54809, 57153, 57274,
+   57921, 58019, 58363, 61722, 65268, 65341, 65373, 65406,
+   65408, 65410, 65415, 65424, 65436, 65439, 65450, 65462,
+   65472, 65476, 65478, 65480, 65482, 65488, 65506, 65511,
+   65514, 65521, 65527, 65528, 65529,
+  };
+
+  int ret = c;
+
+  assert( sizeof(unsigned short)==2 && sizeof(unsigned char)==1 );
+
+  if( c<128 ){
+    if( c>='A' && c<='Z' ) ret = c + ('a' - 'A');
+  }else if( c<65536 ){
+    const struct TableEntry *p;
+    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
+    int iLo = 0;
+    int iRes = -1;
+
+    assert( c>aEntry[0].iCode );
+    while( iHi>=iLo ){
+      int iTest = (iHi + iLo) / 2;
+      int cmp = (c - aEntry[iTest].iCode);
+      if( cmp>=0 ){
+        iRes = iTest;
+        iLo = iTest+1;
+      }else{
+        iHi = iTest-1;
+      }
+    }
+
+    assert( iRes>=0 && c>=aEntry[iRes].iCode );
+    p = &aEntry[iRes];
+    if( c<(p->iCode + p->nRange) && 0==(0x01 & p->flags & (p->iCode ^ c)) ){
+      ret = (c + (aiOff[p->flags>>1])) & 0x0000FFFF;
+      assert( ret>0 );
+    }
+
+    if( eRemoveDiacritic ){
+      ret = fts5_remove_diacritic(ret, eRemoveDiacritic==2);
+    }
+  }
+
+  else if( c>=66560 && c<66600 ){
+    ret = c + 40;
+  }
+
+  return ret;
+}
+
+
+static int sqlite3Fts5UnicodeCatParse(const char *zCat, u8 *aArray){
+  aArray[0] = 1;
+  switch( zCat[0] ){
+    case 'C':
+          switch( zCat[1] ){
+            case 'c': aArray[1] = 1; break;
+            case 'f': aArray[2] = 1; break;
+            case 'n': aArray[3] = 1; break;
+            case 's': aArray[4] = 1; break;
+            case 'o': aArray[31] = 1; break;
+            case '*':
+              aArray[1] = 1;
+              aArray[2] = 1;
+              aArray[3] = 1;
+              aArray[4] = 1;
+              aArray[31] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'L':
+          switch( zCat[1] ){
+            case 'l': aArray[5] = 1; break;
+            case 'm': aArray[6] = 1; break;
+            case 'o': aArray[7] = 1; break;
+            case 't': aArray[8] = 1; break;
+            case 'u': aArray[9] = 1; break;
+            case 'C': aArray[30] = 1; break;
+            case '*':
+              aArray[5] = 1;
+              aArray[6] = 1;
+              aArray[7] = 1;
+              aArray[8] = 1;
+              aArray[9] = 1;
+              aArray[30] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'M':
+          switch( zCat[1] ){
+            case 'c': aArray[10] = 1; break;
+            case 'e': aArray[11] = 1; break;
+            case 'n': aArray[12] = 1; break;
+            case '*':
+              aArray[10] = 1;
+              aArray[11] = 1;
+              aArray[12] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'N':
+          switch( zCat[1] ){
+            case 'd': aArray[13] = 1; break;
+            case 'l': aArray[14] = 1; break;
+            case 'o': aArray[15] = 1; break;
+            case '*':
+              aArray[13] = 1;
+              aArray[14] = 1;
+              aArray[15] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'P':
+          switch( zCat[1] ){
+            case 'c': aArray[16] = 1; break;
+            case 'd': aArray[17] = 1; break;
+            case 'e': aArray[18] = 1; break;
+            case 'f': aArray[19] = 1; break;
+            case 'i': aArray[20] = 1; break;
+            case 'o': aArray[21] = 1; break;
+            case 's': aArray[22] = 1; break;
+            case '*':
+              aArray[16] = 1;
+              aArray[17] = 1;
+              aArray[18] = 1;
+              aArray[19] = 1;
+              aArray[20] = 1;
+              aArray[21] = 1;
+              aArray[22] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'S':
+          switch( zCat[1] ){
+            case 'c': aArray[23] = 1; break;
+            case 'k': aArray[24] = 1; break;
+            case 'm': aArray[25] = 1; break;
+            case 'o': aArray[26] = 1; break;
+            case '*':
+              aArray[23] = 1;
+              aArray[24] = 1;
+              aArray[25] = 1;
+              aArray[26] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+    case 'Z':
+          switch( zCat[1] ){
+            case 'l': aArray[27] = 1; break;
+            case 'p': aArray[28] = 1; break;
+            case 's': aArray[29] = 1; break;
+            case '*':
+              aArray[27] = 1;
+              aArray[28] = 1;
+              aArray[29] = 1;
+              break;
+            default: return 1;          }
+          break;
+
+
+    default:
+      return 1;
+  }
+  return 0;
+}
+
+static u16 aFts5UnicodeBlock[] = {
+    0,     1471,  1753,  1760,  1760,  1760,  1760,  1760,  1760,  1760,
+    1760,  1760,  1760,  1760,  1760,  1763,  1765,
+  };
+static u16 aFts5UnicodeMap[] = {
+    0,     32,    33,    36,    37,    40,    41,    42,    43,    44,
+    45,    46,    48,    58,    60,    63,    65,    91,    92,    93,
+    94,    95,    96,    97,    123,   124,   125,   126,   127,   160,
+    161,   162,   166,   167,   168,   169,   170,   171,   172,   173,
+    174,   175,   176,   177,   178,   180,   181,   182,   184,   185,
+    186,   187,   188,   191,   192,   215,   216,   223,   247,   248,
+    256,   312,   313,   329,   330,   377,   383,   385,   387,   388,
+    391,   394,   396,   398,   402,   403,   405,   406,   409,   412,
+    414,   415,   417,   418,   423,   427,   428,   431,   434,   436,
+    437,   440,   442,   443,   444,   446,   448,   452,   453,   454,
+    455,   456,   457,   458,   459,   460,   461,   477,   478,   496,
+    497,   498,   499,   500,   503,   505,   506,   564,   570,   572,
+    573,   575,   577,   580,   583,   584,   592,   660,   661,   688,
+    706,   710,   722,   736,   741,   748,   749,   750,   751,   768,
+    880,   884,   885,   886,   890,   891,   894,   900,   902,   903,
+    904,   908,   910,   912,   913,   931,   940,   975,   977,   978,
+    981,   984,   1008,  1012,  1014,  1015,  1018,  1020,  1021,  1072,
+    1120,  1154,  1155,  1160,  1162,  1217,  1231,  1232,  1329,  1369,
+    1370,  1377,  1417,  1418,  1423,  1425,  1470,  1471,  1472,  1473,
+    1475,  1476,  1478,  1479,  1488,  1520,  1523,  1536,  1542,  1545,
+    1547,  1548,  1550,  1552,  1563,  1566,  1568,  1600,  1601,  1611,
+    1632,  1642,  1646,  1648,  1649,  1748,  1749,  1750,  1757,  1758,
+    1759,  1765,  1767,  1769,  1770,  1774,  1776,  1786,  1789,  1791,
+    1792,  1807,  1808,  1809,  1810,  1840,  1869,  1958,  1969,  1984,
+    1994,  2027,  2036,  2038,  2039,  2042,  2048,  2070,  2074,  2075,
+    2084,  2085,  2088,  2089,  2096,  2112,  2137,  2142,  2208,  2210,
+    2276,  2304,  2307,  2308,  2362,  2363,  2364,  2365,  2366,  2369,
+    2377,  2381,  2382,  2384,  2385,  2392,  2402,  2404,  2406,  2416,
+    2417,  2418,  2425,  2433,  2434,  2437,  2447,  2451,  2474,  2482,
+    2486,  2492,  2493,  2494,  2497,  2503,  2507,  2509,  2510,  2519,
+    2524,  2527,  2530,  2534,  2544,  2546,  2548,  2554,  2555,  2561,
+    2563,  2565,  2575,  2579,  2602,  2610,  2613,  2616,  2620,  2622,
+    2625,  2631,  2635,  2641,  2649,  2654,  2662,  2672,  2674,  2677,
+    2689,  2691,  2693,  2703,  2707,  2730,  2738,  2741,  2748,  2749,
+    2750,  2753,  2759,  2761,  2763,  2765,  2768,  2784,  2786,  2790,
+    2800,  2801,  2817,  2818,  2821,  2831,  2835,  2858,  2866,  2869,
+    2876,  2877,  2878,  2879,  2880,  2881,  2887,  2891,  2893,  2902,
+    2903,  2908,  2911,  2914,  2918,  2928,  2929,  2930,  2946,  2947,
+    2949,  2958,  2962,  2969,  2972,  2974,  2979,  2984,  2990,  3006,
+    3008,  3009,  3014,  3018,  3021,  3024,  3031,  3046,  3056,  3059,
+    3065,  3066,  3073,  3077,  3086,  3090,  3114,  3125,  3133,  3134,
+    3137,  3142,  3146,  3157,  3160,  3168,  3170,  3174,  3192,  3199,
+    3202,  3205,  3214,  3218,  3242,  3253,  3260,  3261,  3262,  3263,
+    3264,  3270,  3271,  3274,  3276,  3285,  3294,  3296,  3298,  3302,
+    3313,  3330,  3333,  3342,  3346,  3389,  3390,  3393,  3398,  3402,
+    3405,  3406,  3415,  3424,  3426,  3430,  3440,  3449,  3450,  3458,
+    3461,  3482,  3507,  3517,  3520,  3530,  3535,  3538,  3542,  3544,
+    3570,  3572,  3585,  3633,  3634,  3636,  3647,  3648,  3654,  3655,
+    3663,  3664,  3674,  3713,  3716,  3719,  3722,  3725,  3732,  3737,
+    3745,  3749,  3751,  3754,  3757,  3761,  3762,  3764,  3771,  3773,
+    3776,  3782,  3784,  3792,  3804,  3840,  3841,  3844,  3859,  3860,
+    3861,  3864,  3866,  3872,  3882,  3892,  3893,  3894,  3895,  3896,
+    3897,  3898,  3899,  3900,  3901,  3902,  3904,  3913,  3953,  3967,
+    3968,  3973,  3974,  3976,  3981,  3993,  4030,  4038,  4039,  4046,
+    4048,  4053,  4057,  4096,  4139,  4141,  4145,  4146,  4152,  4153,
+    4155,  4157,  4159,  4160,  4170,  4176,  4182,  4184,  4186,  4190,
+    4193,  4194,  4197,  4199,  4206,  4209,  4213,  4226,  4227,  4229,
+    4231,  4237,  4238,  4239,  4240,  4250,  4253,  4254,  4256,  4295,
+    4301,  4304,  4347,  4348,  4349,  4682,  4688,  4696,  4698,  4704,
+    4746,  4752,  4786,  4792,  4800,  4802,  4808,  4824,  4882,  4888,
+    4957,  4960,  4969,  4992,  5008,  5024,  5120,  5121,  5741,  5743,
+    5760,  5761,  5787,  5788,  5792,  5867,  5870,  5888,  5902,  5906,
+    5920,  5938,  5941,  5952,  5970,  5984,  5998,  6002,  6016,  6068,
+    6070,  6071,  6078,  6086,  6087,  6089,  6100,  6103,  6104,  6107,
+    6108,  6109,  6112,  6128,  6144,  6150,  6151,  6155,  6158,  6160,
+    6176,  6211,  6212,  6272,  6313,  6314,  6320,  6400,  6432,  6435,
+    6439,  6441,  6448,  6450,  6451,  6457,  6464,  6468,  6470,  6480,
+    6512,  6528,  6576,  6593,  6600,  6608,  6618,  6622,  6656,  6679,
+    6681,  6686,  6688,  6741,  6742,  6743,  6744,  6752,  6753,  6754,
+    6755,  6757,  6765,  6771,  6783,  6784,  6800,  6816,  6823,  6824,
+    6912,  6916,  6917,  6964,  6965,  6966,  6971,  6972,  6973,  6978,
+    6979,  6981,  6992,  7002,  7009,  7019,  7028,  7040,  7042,  7043,
+    7073,  7074,  7078,  7080,  7082,  7083,  7084,  7086,  7088,  7098,
+    7142,  7143,  7144,  7146,  7149,  7150,  7151,  7154,  7164,  7168,
+    7204,  7212,  7220,  7222,  7227,  7232,  7245,  7248,  7258,  7288,
+    7294,  7360,  7376,  7379,  7380,  7393,  7394,  7401,  7405,  7406,
+    7410,  7412,  7413,  7424,  7468,  7531,  7544,  7545,  7579,  7616,
+    7676,  7680,  7830,  7838,  7936,  7944,  7952,  7960,  7968,  7976,
+    7984,  7992,  8000,  8008,  8016,  8025,  8027,  8029,  8031,  8033,
+    8040,  8048,  8064,  8072,  8080,  8088,  8096,  8104,  8112,  8118,
+    8120,  8124,  8125,  8126,  8127,  8130,  8134,  8136,  8140,  8141,
+    8144,  8150,  8152,  8157,  8160,  8168,  8173,  8178,  8182,  8184,
+    8188,  8189,  8192,  8203,  8208,  8214,  8216,  8217,  8218,  8219,
+    8221,  8222,  8223,  8224,  8232,  8233,  8234,  8239,  8240,  8249,
+    8250,  8251,  8255,  8257,  8260,  8261,  8262,  8263,  8274,  8275,
+    8276,  8277,  8287,  8288,  8298,  8304,  8305,  8308,  8314,  8317,
+    8318,  8319,  8320,  8330,  8333,  8334,  8336,  8352,  8400,  8413,
+    8417,  8418,  8421,  8448,  8450,  8451,  8455,  8456,  8458,  8459,
+    8462,  8464,  8467,  8468,  8469,  8470,  8472,  8473,  8478,  8484,
+    8485,  8486,  8487,  8488,  8489,  8490,  8494,  8495,  8496,  8500,
+    8501,  8505,  8506,  8508,  8510,  8512,  8517,  8519,  8522,  8523,
+    8524,  8526,  8527,  8528,  8544,  8579,  8581,  8585,  8592,  8597,
+    8602,  8604,  8608,  8609,  8611,  8612,  8614,  8615,  8622,  8623,
+    8654,  8656,  8658,  8659,  8660,  8661,  8692,  8960,  8968,  8972,
+    8992,  8994,  9001,  9002,  9003,  9084,  9085,  9115,  9140,  9180,
+    9186,  9216,  9280,  9312,  9372,  9450,  9472,  9655,  9656,  9665,
+    9666,  9720,  9728,  9839,  9840,  9985,  10088, 10089, 10090, 10091,
+    10092, 10093, 10094, 10095, 10096, 10097, 10098, 10099, 10100, 10101,
+    10102, 10132, 10176, 10181, 10182, 10183, 10214, 10215, 10216, 10217,
+    10218, 10219, 10220, 10221, 10222, 10223, 10224, 10240, 10496, 10627,
+    10628, 10629, 10630, 10631, 10632, 10633, 10634, 10635, 10636, 10637,
+    10638, 10639, 10640, 10641, 10642, 10643, 10644, 10645, 10646, 10647,
+    10648, 10649, 10712, 10713, 10714, 10715, 10716, 10748, 10749, 10750,
+    11008, 11056, 11077, 11079, 11088, 11264, 11312, 11360, 11363, 11365,
+    11367, 11374, 11377, 11378, 11380, 11381, 11383, 11388, 11390, 11393,
+    11394, 11492, 11493, 11499, 11503, 11506, 11513, 11517, 11518, 11520,
+    11559, 11565, 11568, 11631, 11632, 11647, 11648, 11680, 11688, 11696,
+    11704, 11712, 11720, 11728, 11736, 11744, 11776, 11778, 11779, 11780,
+    11781, 11782, 11785, 11786, 11787, 11788, 11789, 11790, 11799, 11800,
+    11802, 11803, 11804, 11805, 11806, 11808, 11809, 11810, 11811, 11812,
+    11813, 11814, 11815, 11816, 11817, 11818, 11823, 11824, 11834, 11904,
+    11931, 12032, 12272, 12288, 12289, 12292, 12293, 12294, 12295, 12296,
+    12297, 12298, 12299, 12300, 12301, 12302, 12303, 12304, 12305, 12306,
+    12308, 12309, 12310, 12311, 12312, 12313, 12314, 12315, 12316, 12317,
+    12318, 12320, 12321, 12330, 12334, 12336, 12337, 12342, 12344, 12347,
+    12348, 12349, 12350, 12353, 12441, 12443, 12445, 12447, 12448, 12449,
+    12539, 12540, 12543, 12549, 12593, 12688, 12690, 12694, 12704, 12736,
+    12784, 12800, 12832, 12842, 12872, 12880, 12881, 12896, 12928, 12938,
+    12977, 12992, 13056, 13312, 19893, 19904, 19968, 40908, 40960, 40981,
+    40982, 42128, 42192, 42232, 42238, 42240, 42508, 42509, 42512, 42528,
+    42538, 42560, 42606, 42607, 42608, 42611, 42612, 42622, 42623, 42624,
+    42655, 42656, 42726, 42736, 42738, 42752, 42775, 42784, 42786, 42800,
+    42802, 42864, 42865, 42873, 42878, 42888, 42889, 42891, 42896, 42912,
+    43000, 43002, 43003, 43010, 43011, 43014, 43015, 43019, 43020, 43043,
+    43045, 43047, 43048, 43056, 43062, 43064, 43065, 43072, 43124, 43136,
+    43138, 43188, 43204, 43214, 43216, 43232, 43250, 43256, 43259, 43264,
+    43274, 43302, 43310, 43312, 43335, 43346, 43359, 43360, 43392, 43395,
+    43396, 43443, 43444, 43446, 43450, 43452, 43453, 43457, 43471, 43472,
+    43486, 43520, 43561, 43567, 43569, 43571, 43573, 43584, 43587, 43588,
+    43596, 43597, 43600, 43612, 43616, 43632, 43633, 43639, 43642, 43643,
+    43648, 43696, 43697, 43698, 43701, 43703, 43705, 43710, 43712, 43713,
+    43714, 43739, 43741, 43742, 43744, 43755, 43756, 43758, 43760, 43762,
+    43763, 43765, 43766, 43777, 43785, 43793, 43808, 43816, 43968, 44003,
+    44005, 44006, 44008, 44009, 44011, 44012, 44013, 44016, 44032, 55203,
+    55216, 55243, 55296, 56191, 56319, 57343, 57344, 63743, 63744, 64112,
+    64256, 64275, 64285, 64286, 64287, 64297, 64298, 64312, 64318, 64320,
+    64323, 64326, 64434, 64467, 64830, 64831, 64848, 64914, 65008, 65020,
+    65021, 65024, 65040, 65047, 65048, 65049, 65056, 65072, 65073, 65075,
+    65077, 65078, 65079, 65080, 65081, 65082, 65083, 65084, 65085, 65086,
+    65087, 65088, 65089, 65090, 65091, 65092, 65093, 65095, 65096, 65097,
+    65101, 65104, 65108, 65112, 65113, 65114, 65115, 65116, 65117, 65118,
+    65119, 65122, 65123, 65124, 65128, 65129, 65130, 65136, 65142, 65279,
+    65281, 65284, 65285, 65288, 65289, 65290, 65291, 65292, 65293, 65294,
+    65296, 65306, 65308, 65311, 65313, 65339, 65340, 65341, 65342, 65343,
+    65344, 65345, 65371, 65372, 65373, 65374, 65375, 65376, 65377, 65378,
+    65379, 65380, 65382, 65392, 65393, 65438, 65440, 65474, 65482, 65490,
+    65498, 65504, 65506, 65507, 65508, 65509, 65512, 65513, 65517, 65529,
+    65532, 0,     13,    40,    60,    63,    80,    128,   256,   263,
+    311,   320,   373,   377,   394,   400,   464,   509,   640,   672,
+    768,   800,   816,   833,   834,   842,   896,   927,   928,   968,
+    976,   977,   1024,  1064,  1104,  1184,  2048,  2056,  2058,  2103,
+    2108,  2111,  2135,  2136,  2304,  2326,  2335,  2336,  2367,  2432,
+    2494,  2560,  2561,  2565,  2572,  2576,  2581,  2585,  2616,  2623,
+    2624,  2640,  2656,  2685,  2687,  2816,  2873,  2880,  2904,  2912,
+    2936,  3072,  3680,  4096,  4097,  4098,  4099,  4152,  4167,  4178,
+    4198,  4224,  4226,  4227,  4272,  4275,  4279,  4281,  4283,  4285,
+    4286,  4304,  4336,  4352,  4355,  4391,  4396,  4397,  4406,  4416,
+    4480,  4482,  4483,  4531,  4534,  4543,  4545,  4549,  4560,  5760,
+    5803,  5804,  5805,  5806,  5808,  5814,  5815,  5824,  8192,  9216,
+    9328,  12288, 26624, 28416, 28496, 28497, 28559, 28563, 45056, 53248,
+    53504, 53545, 53605, 53607, 53610, 53613, 53619, 53627, 53635, 53637,
+    53644, 53674, 53678, 53760, 53826, 53829, 54016, 54112, 54272, 54298,
+    54324, 54350, 54358, 54376, 54402, 54428, 54430, 54434, 54437, 54441,
+    54446, 54454, 54459, 54461, 54469, 54480, 54506, 54532, 54535, 54541,
+    54550, 54558, 54584, 54587, 54592, 54598, 54602, 54610, 54636, 54662,
+    54688, 54714, 54740, 54766, 54792, 54818, 54844, 54870, 54896, 54922,
+    54952, 54977, 54978, 55003, 55004, 55010, 55035, 55036, 55061, 55062,
+    55068, 55093, 55094, 55119, 55120, 55126, 55151, 55152, 55177, 55178,
+    55184, 55209, 55210, 55235, 55236, 55242, 55246, 60928, 60933, 60961,
+    60964, 60967, 60969, 60980, 60985, 60987, 60994, 60999, 61001, 61003,
+    61005, 61009, 61012, 61015, 61017, 61019, 61021, 61023, 61025, 61028,
+    61031, 61036, 61044, 61049, 61054, 61056, 61067, 61089, 61093, 61099,
+    61168, 61440, 61488, 61600, 61617, 61633, 61649, 61696, 61712, 61744,
+    61808, 61926, 61968, 62016, 62032, 62208, 62256, 62263, 62336, 62368,
+    62406, 62432, 62464, 62528, 62530, 62713, 62720, 62784, 62800, 62971,
+    63045, 63104, 63232, 0,     42710, 42752, 46900, 46912, 47133, 63488,
+    1,     32,    256,   0,     65533,
+  };
+static u16 aFts5UnicodeData[] = {
+    1025,  61,    117,   55,    117,   54,    50,    53,    57,    53,
+    49,    85,    333,   85,    121,   85,    841,   54,    53,    50,
+    56,    48,    56,    837,   54,    57,    50,    57,    1057,  61,
+    53,    151,   58,    53,    56,    58,    39,    52,    57,    34,
+    58,    56,    58,    57,    79,    56,    37,    85,    56,    47,
+    39,    51,    111,   53,    745,   57,    233,   773,   57,    261,
+    1822,  37,    542,   37,    1534,  222,   69,    73,    37,    126,
+    126,   73,    69,    137,   37,    73,    37,    105,   101,   73,
+    37,    73,    37,    190,   158,   37,    126,   126,   73,    37,
+    126,   94,    37,    39,    94,    69,    135,   41,    40,    37,
+    41,    40,    37,    41,    40,    37,    542,   37,    606,   37,
+    41,    40,    37,    126,   73,    37,    1886,  197,   73,    37,
+    73,    69,    126,   105,   37,    286,   2181,  39,    869,   582,
+    152,   390,   472,   166,   248,   38,    56,    38,    568,   3596,
+    158,   38,    56,    94,    38,    101,   53,    88,    41,    53,
+    105,   41,    73,    37,    553,   297,   1125,  94,    37,    105,
+    101,   798,   133,   94,    57,    126,   94,    37,    1641,  1541,
+    1118,  58,    172,   75,    1790,  478,   37,    2846,  1225,  38,
+    213,   1253,  53,    49,    55,    1452,  49,    44,    53,    76,
+    53,    76,    53,    44,    871,   103,   85,    162,   121,   85,
+    55,    85,    90,    364,   53,    85,    1031,  38,    327,   684,
+    333,   149,   71,    44,    3175,  53,    39,    236,   34,    58,
+    204,   70,    76,    58,    140,   71,    333,   103,   90,    39,
+    469,   34,    39,    44,    967,   876,   2855,  364,   39,    333,
+    1063,  300,   70,    58,    117,   38,    711,   140,   38,    300,
+    38,    108,   38,    172,   501,   807,   108,   53,    39,    359,
+    876,   108,   42,    1735,  44,    42,    44,    39,    106,   268,
+    138,   44,    74,    39,    236,   327,   76,    85,    333,   53,
+    38,    199,   231,   44,    74,    263,   71,    711,   231,   39,
+    135,   44,    39,    106,   140,   74,    74,    44,    39,    42,
+    71,    103,   76,    333,   71,    87,    207,   58,    55,    76,
+    42,    199,   71,    711,   231,   71,    71,    71,    44,    106,
+    76,    76,    108,   44,    135,   39,    333,   76,    103,   44,
+    76,    42,    295,   103,   711,   231,   71,    167,   44,    39,
+    106,   172,   76,    42,    74,    44,    39,    71,    76,    333,
+    53,    55,    44,    74,    263,   71,    711,   231,   71,    167,
+    44,    39,    42,    44,    42,    140,   74,    74,    44,    44,
+    42,    71,    103,   76,    333,   58,    39,    207,   44,    39,
+    199,   103,   135,   71,    39,    71,    71,    103,   391,   74,
+    44,    74,    106,   106,   44,    39,    42,    333,   111,   218,
+    55,    58,    106,   263,   103,   743,   327,   167,   39,    108,
+    138,   108,   140,   76,    71,    71,    76,    333,   239,   58,
+    74,    263,   103,   743,   327,   167,   44,    39,    42,    44,
+    170,   44,    74,    74,    76,    74,    39,    71,    76,    333,
+    71,    74,    263,   103,   1319,  39,    106,   140,   106,   106,
+    44,    39,    42,    71,    76,    333,   207,   58,    199,   74,
+    583,   775,   295,   39,    231,   44,    106,   108,   44,    266,
+    74,    53,    1543,  44,    71,    236,   55,    199,   38,    268,
+    53,    333,   85,    71,    39,    71,    39,    39,    135,   231,
+    103,   39,    39,    71,    135,   44,    71,    204,   76,    39,
+    167,   38,    204,   333,   135,   39,    122,   501,   58,    53,
+    122,   76,    218,   333,   335,   58,    44,    58,    44,    58,
+    44,    54,    50,    54,    50,    74,    263,   1159,  460,   42,
+    172,   53,    76,    167,   364,   1164,  282,   44,    218,   90,
+    181,   154,   85,    1383,  74,    140,   42,    204,   42,    76,
+    74,    76,    39,    333,   213,   199,   74,    76,    135,   108,
+    39,    106,   71,    234,   103,   140,   423,   44,    74,    76,
+    202,   44,    39,    42,    333,   106,   44,    90,    1225,  41,
+    41,    1383,  53,    38,    10631, 135,   231,   39,    135,   1319,
+    135,   1063,  135,   231,   39,    135,   487,   1831,  135,   2151,
+    108,   309,   655,   519,   346,   2727,  49,    19847, 85,    551,
+    61,    839,   54,    50,    2407,  117,   110,   423,   135,   108,
+    583,   108,   85,    583,   76,    423,   103,   76,    1671,  76,
+    42,    236,   266,   44,    74,    364,   117,   38,    117,   55,
+    39,    44,    333,   335,   213,   49,    149,   108,   61,    333,
+    1127,  38,    1671,  1319,  44,    39,    2247,  935,   108,   138,
+    76,    106,   74,    44,    202,   108,   58,    85,    333,   967,
+    167,   1415,  554,   231,   74,    333,   47,    1114,  743,   76,
+    106,   85,    1703,  42,    44,    42,    236,   44,    42,    44,
+    74,    268,   202,   332,   44,    333,   333,   245,   38,    213,
+    140,   42,    1511,  44,    42,    172,   42,    44,    170,   44,
+    74,    231,   333,   245,   346,   300,   314,   76,    42,    967,
+    42,    140,   74,    76,    42,    44,    74,    71,    333,   1415,
+    44,    42,    76,    106,   44,    42,    108,   74,    149,   1159,
+    266,   268,   74,    76,    181,   333,   103,   333,   967,   198,
+    85,    277,   108,   53,    428,   42,    236,   135,   44,    135,
+    74,    44,    71,    1413,  2022,  421,   38,    1093,  1190,  1260,
+    140,   4830,  261,   3166,  261,   265,   197,   201,   261,   265,
+    261,   265,   197,   201,   261,   41,    41,    41,    94,    229,
+    265,   453,   261,   264,   261,   264,   261,   264,   165,   69,
+    137,   40,    56,    37,    120,   101,   69,    137,   40,    120,
+    133,   69,    137,   120,   261,   169,   120,   101,   69,    137,
+    40,    88,    381,   162,   209,   85,    52,    51,    54,    84,
+    51,    54,    52,    277,   59,    60,    162,   61,    309,   52,
+    51,    149,   80,    117,   57,    54,    50,    373,   57,    53,
+    48,    341,   61,    162,   194,   47,    38,    207,   121,   54,
+    50,    38,    335,   121,   54,    50,    422,   855,   428,   139,
+    44,    107,   396,   90,    41,    154,   41,    90,    37,    105,
+    69,    105,   37,    58,    41,    90,    57,    169,   218,   41,
+    58,    41,    58,    41,    58,    137,   58,    37,    137,   37,
+    135,   37,    90,    69,    73,    185,   94,    101,   58,    57,
+    90,    37,    58,    527,   1134,  94,    142,   47,    185,   186,
+    89,    154,   57,    90,    57,    90,    57,    250,   57,    1018,
+    89,    90,    57,    58,    57,    1018,  8601,  282,   153,   666,
+    89,    250,   54,    50,    2618,  57,    986,   825,   1306,  217,
+    602,   1274,  378,   1935,  2522,  719,   5882,  57,    314,   57,
+    1754,  281,   3578,  57,    4634,  3322,  54,    50,    54,    50,
+    54,    50,    54,    50,    54,    50,    54,    50,    54,    50,
+    975,   1434,  185,   54,    50,    1017,  54,    50,    54,    50,
+    54,    50,    54,    50,    54,    50,    537,   8218,  4217,  54,
+    50,    54,    50,    54,    50,    54,    50,    54,    50,    54,
+    50,    54,    50,    54,    50,    54,    50,    54,    50,    54,
+    50,    2041,  54,    50,    54,    50,    1049,  54,    50,    8281,
+    1562,  697,   90,    217,   346,   1513,  1509,  126,   73,    69,
+    254,   105,   37,    94,    37,    94,    165,   70,    105,   37,
+    3166,  37,    218,   158,   108,   94,    149,   47,    85,    1221,
+    37,    37,    1799,  38,    53,    44,    743,   231,   231,   231,
+    231,   231,   231,   231,   231,   1036,  85,    52,    51,    52,
+    51,    117,   52,    51,    53,    52,    51,    309,   49,    85,
+    49,    53,    52,    51,    85,    52,    51,    54,    50,    54,
+    50,    54,    50,    54,    50,    181,   38,    341,   81,    858,
+    2874,  6874,  410,   61,    117,   58,    38,    39,    46,    54,
+    50,    54,    50,    54,    50,    54,    50,    54,    50,    90,
+    54,    50,    54,    50,    54,    50,    54,    50,    49,    54,
+    82,    58,    302,   140,   74,    49,    166,   90,    110,   38,
+    39,    53,    90,    2759,  76,    88,    70,    39,    49,    2887,
+    53,    102,   39,    1319,  3015,  90,    143,   346,   871,   1178,
+    519,   1018,  335,   986,   271,   58,    495,   1050,  335,   1274,
+    495,   2042,  8218,  39,    39,    2074,  39,    39,    679,   38,
+    36583, 1786,  1287,  198,   85,    8583,  38,    117,   519,   333,
+    71,    1502,  39,    44,    107,   53,    332,   53,    38,    798,
+    44,    2247,  334,   76,    213,   760,   294,   88,    478,   69,
+    2014,  38,    261,   190,   350,   38,    88,    158,   158,   382,
+    70,    37,    231,   44,    103,   44,    135,   44,    743,   74,
+    76,    42,    154,   207,   90,    55,    58,    1671,  149,   74,
+    1607,  522,   44,    85,    333,   588,   199,   117,   39,    333,
+    903,   268,   85,    743,   364,   74,    53,    935,   108,   42,
+    1511,  44,    74,    140,   74,    44,    138,   437,   38,    333,
+    85,    1319,  204,   74,    76,    74,    76,    103,   44,    263,
+    44,    42,    333,   149,   519,   38,    199,   122,   39,    42,
+    1543,  44,    39,    108,   71,    76,    167,   76,    39,    44,
+    39,    71,    38,    85,    359,   42,    76,    74,    85,    39,
+    70,    42,    44,    199,   199,   199,   231,   231,   1127,  74,
+    44,    74,    44,    74,    53,    42,    44,    333,   39,    39,
+    743,   1575,  36,    68,    68,    36,    63,    63,    11719, 3399,
+    229,   165,   39,    44,    327,   57,    423,   167,   39,    71,
+    71,    3463,  536,   11623, 54,    50,    2055,  1735,  391,   55,
+    58,    524,   245,   54,    50,    53,    236,   53,    81,    80,
+    54,    50,    54,    50,    54,    50,    54,    50,    54,    50,
+    54,    50,    54,    50,    54,    50,    85,    54,    50,    149,
+    112,   117,   149,   49,    54,    50,    54,    50,    54,    50,
+    117,   57,    49,    121,   53,    55,    85,    167,   4327,  34,
+    117,   55,    117,   54,    50,    53,    57,    53,    49,    85,
+    333,   85,    121,   85,    841,   54,    53,    50,    56,    48,
+    56,    837,   54,    57,    50,    57,    54,    50,    53,    54,
+    50,    85,    327,   38,    1447,  70,    999,   199,   199,   199,
+    103,   87,    57,    56,    58,    87,    58,    153,   90,    98,
+    90,    391,   839,   615,   71,    487,   455,   3943,  117,   1455,
+    314,   1710,  143,   570,   47,    410,   1466,  44,    935,   1575,
+    999,   143,   551,   46,    263,   46,    967,   53,    1159,  263,
+    53,    174,   1289,  1285,  2503,  333,   199,   39,    1415,  71,
+    39,    743,   53,    271,   711,   207,   53,    839,   53,    1799,
+    71,    39,    108,   76,    140,   135,   103,   871,   108,   44,
+    271,   309,   935,   79,    53,    1735,  245,   711,   271,   615,
+    271,   2343,  1007,  42,    44,    42,    1703,  492,   245,   655,
+    333,   76,    42,    1447,  106,   140,   74,    76,    85,    34,
+    149,   807,   333,   108,   1159,  172,   42,    268,   333,   149,
+    76,    42,    1543,  106,   300,   74,    135,   149,   333,   1383,
+    44,    42,    44,    74,    204,   42,    44,    333,   28135, 3182,
+    149,   34279, 18215, 2215,  39,    1482,  140,   422,   71,    7898,
+    1274,  1946,  74,    108,   122,   202,   258,   268,   90,    236,
+    986,   140,   1562,  2138,  108,   58,    2810,  591,   841,   837,
+    841,   229,   581,   841,   837,   41,    73,    41,    73,    137,
+    265,   133,   37,    229,   357,   841,   837,   73,    137,   265,
+    233,   837,   73,    137,   169,   41,    233,   837,   841,   837,
+    841,   837,   841,   837,   841,   837,   841,   837,   841,   901,
+    809,   57,    805,   57,    197,   809,   57,    805,   57,    197,
+    809,   57,    805,   57,    197,   809,   57,    805,   57,    197,
+    809,   57,    805,   57,    197,   94,    1613,  135,   871,   71,
+    39,    39,    327,   135,   39,    39,    39,    39,    39,    39,
+    103,   71,    39,    39,    39,    39,    39,    39,    71,    39,
+    135,   231,   135,   135,   39,    327,   551,   103,   167,   551,
+    89,    1434,  3226,  506,   474,   506,   506,   367,   1018,  1946,
+    1402,  954,   1402,  314,   90,    1082,  218,   2266,  666,   1210,
+    186,   570,   2042,  58,    5850,  154,   2010,  154,   794,   2266,
+    378,   2266,  3738,  39,    39,    39,    39,    39,    39,    17351,
+    34,    3074,  7692,  63,    63,
+  };
+
+static int sqlite3Fts5UnicodeCategory(u32 iCode) {
+  int iRes = -1;
+  int iHi;
+  int iLo;
+  int ret;
+  u16 iKey;
+
+  if( iCode>=(1<<20) ){
+    return 0;
+  }
+  iLo = aFts5UnicodeBlock[(iCode>>16)];
+  iHi = aFts5UnicodeBlock[1+(iCode>>16)];
+  iKey = (iCode & 0xFFFF);
+  while( iHi>iLo ){
+    int iTest = (iHi + iLo) / 2;
+    assert( iTest>=iLo && iTest<iHi );
+    if( iKey>=aFts5UnicodeMap[iTest] ){
+      iRes = iTest;
+      iLo = iTest+1;
+    }else{
+      iHi = iTest;
+    }
+  }
+
+  if( iRes<0 ) return 0;
+  if( iKey>=(aFts5UnicodeMap[iRes]+(aFts5UnicodeData[iRes]>>5)) ) return 0;
+  ret = aFts5UnicodeData[iRes] & 0x1F;
+  if( ret!=30 ) return ret;
+  return ((iKey - aFts5UnicodeMap[iRes]) & 0x01) ? 5 : 9;
+}
+
+static void sqlite3Fts5UnicodeAscii(u8 *aArray, u8 *aAscii){
+  int i = 0;
+  int iTbl = 0;
+  while( i<128 ){
+    int bToken = aArray[ aFts5UnicodeData[iTbl] & 0x1F ];
+    int n = (aFts5UnicodeData[iTbl] >> 5) + i;
+    for(; i<128 && i<n; i++){
+      aAscii[i] = (u8)bToken;
+    }
+    iTbl++;
+  }
+  aAscii[0] = 0;                  /* 0x00 is never a token character */
+}
+
+
+/*
+** 2015 May 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Routines for varint serialization and deserialization.
+*/
+
+
+/* #include "fts5Int.h" */
+
+/*
+** This is a copy of the sqlite3GetVarint32() routine from the SQLite core.
+** Except, this version does handle the single byte case that the core
+** version depends on being handled before its function is called.
+*/
+static int sqlite3Fts5GetVarint32(const unsigned char *p, u32 *v){
+  u32 a,b;
+
+  /* The 1-byte case. Overwhelmingly the most common. */
+  a = *p;
+  /* a: p0 (unmasked) */
+  if (!(a&0x80))
+  {
+    /* Values between 0 and 127 */
+    *v = a;
+    return 1;
+  }
+
+  /* The 2-byte case */
+  p++;
+  b = *p;
+  /* b: p1 (unmasked) */
+  if (!(b&0x80))
+  {
+    /* Values between 128 and 16383 */
+    a &= 0x7f;
+    a = a<<7;
+    *v = a | b;
+    return 2;
+  }
+
+  /* The 3-byte case */
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<14 | p2 (unmasked) */
+  if (!(a&0x80))
+  {
+    /* Values between 16384 and 2097151 */
+    a &= (0x7f<<14)|(0x7f);
+    b &= 0x7f;
+    b = b<<7;
+    *v = a | b;
+    return 3;
+  }
+
+  /* A 32-bit varint is used to store size information in btrees.
+  ** Objects are rarely larger than 2MiB limit of a 3-byte varint.
+  ** A 3-byte varint is sufficient, for example, to record the size
+  ** of a 1048569-byte BLOB or string.
+  **
+  ** We only unroll the first 1-, 2-, and 3- byte cases.  The very
+  ** rare larger cases can be handled by the slower 64-bit varint
+  ** routine.
+  */
+  {
+    u64 v64;
+    u8 n;
+    p -= 2;
+    n = sqlite3Fts5GetVarint(p, &v64);
+    *v = ((u32)v64) & 0x7FFFFFFF;
+    assert( n>3 && n<=9 );
+    return n;
+  }
+}
+
+
+/*
+** Bitmasks used by sqlite3GetVarint().  These precomputed constants
+** are defined here rather than simply putting the constant expressions
+** inline in order to work around bugs in the RVT compiler.
+**
+** SLOT_2_0     A mask for  (0x7f<<14) | 0x7f
+**
+** SLOT_4_2_0   A mask for  (0x7f<<28) | SLOT_2_0
+*/
+#define SLOT_2_0     0x001fc07f
+#define SLOT_4_2_0   0xf01fc07f
+
+/*
+** Read a 64-bit variable-length integer from memory starting at p[0].
+** Return the number of bytes read.  The value is stored in *v.
+*/
+static u8 sqlite3Fts5GetVarint(const unsigned char *p, u64 *v){
+  u32 a,b,s;
+
+  a = *p;
+  /* a: p0 (unmasked) */
+  if (!(a&0x80))
+  {
+    *v = a;
+    return 1;
+  }
+
+  p++;
+  b = *p;
+  /* b: p1 (unmasked) */
+  if (!(b&0x80))
+  {
+    a &= 0x7f;
+    a = a<<7;
+    a |= b;
+    *v = a;
+    return 2;
+  }
+
+  /* Verify that constants are precomputed correctly */
+  assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
+  assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<14 | p2 (unmasked) */
+  if (!(a&0x80))
+  {
+    a &= SLOT_2_0;
+    b &= 0x7f;
+    b = b<<7;
+    a |= b;
+    *v = a;
+    return 3;
+  }
+
+  /* CSE1 from below */
+  a &= SLOT_2_0;
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<14 | p3 (unmasked) */
+  if (!(b&0x80))
+  {
+    b &= SLOT_2_0;
+    /* moved CSE1 up */
+    /* a &= (0x7f<<14)|(0x7f); */
+    a = a<<7;
+    a |= b;
+    *v = a;
+    return 4;
+  }
+
+  /* a: p0<<14 | p2 (masked) */
+  /* b: p1<<14 | p3 (unmasked) */
+  /* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+  /* moved CSE1 up */
+  /* a &= (0x7f<<14)|(0x7f); */
+  b &= SLOT_2_0;
+  s = a;
+  /* s: p0<<14 | p2 (masked) */
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p0<<28 | p2<<14 | p4 (unmasked) */
+  if (!(a&0x80))
+  {
+    /* we can skip these cause they were (effectively) done above in calc'ing s */
+    /* a &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
+    /* b &= (0x7f<<14)|(0x7f); */
+    b = b<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 5;
+  }
+
+  /* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+  s = s<<7;
+  s |= b;
+  /* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
+
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p1<<28 | p3<<14 | p5 (unmasked) */
+  if (!(b&0x80))
+  {
+    /* we can skip this cause it was (effectively) done above in calc'ing s */
+    /* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
+    a &= SLOT_2_0;
+    a = a<<7;
+    a |= b;
+    s = s>>18;
+    *v = ((u64)s)<<32 | a;
+    return 6;
+  }
+
+  p++;
+  a = a<<14;
+  a |= *p;
+  /* a: p2<<28 | p4<<14 | p6 (unmasked) */
+  if (!(a&0x80))
+  {
+    a &= SLOT_4_2_0;
+    b &= SLOT_2_0;
+    b = b<<7;
+    a |= b;
+    s = s>>11;
+    *v = ((u64)s)<<32 | a;
+    return 7;
+  }
+
+  /* CSE2 from below */
+  a &= SLOT_2_0;
+  p++;
+  b = b<<14;
+  b |= *p;
+  /* b: p3<<28 | p5<<14 | p7 (unmasked) */
+  if (!(b&0x80))
+  {
+    b &= SLOT_4_2_0;
+    /* moved CSE2 up */
+    /* a &= (0x7f<<14)|(0x7f); */
+    a = a<<7;
+    a |= b;
+    s = s>>4;
+    *v = ((u64)s)<<32 | a;
+    return 8;
+  }
+
+  p++;
+  a = a<<15;
+  a |= *p;
+  /* a: p4<<29 | p6<<15 | p8 (unmasked) */
+
+  /* moved CSE2 up */
+  /* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
+  b &= SLOT_2_0;
+  b = b<<8;
+  a |= b;
+
+  s = s<<4;
+  b = p[-4];
+  b &= 0x7f;
+  b = b>>3;
+  s |= b;
+
+  *v = ((u64)s)<<32 | a;
+
+  return 9;
+}
+
+/*
+** The variable-length integer encoding is as follows:
+**
+** KEY:
+**         A = 0xxxxxxx    7 bits of data and one flag bit
+**         B = 1xxxxxxx    7 bits of data and one flag bit
+**         C = xxxxxxxx    8 bits of data
+**
+**  7 bits - A
+** 14 bits - BA
+** 21 bits - BBA
+** 28 bits - BBBA
+** 35 bits - BBBBA
+** 42 bits - BBBBBA
+** 49 bits - BBBBBBA
+** 56 bits - BBBBBBBA
+** 64 bits - BBBBBBBBC
+*/
+
+#ifdef SQLITE_NOINLINE
+# define FTS5_NOINLINE SQLITE_NOINLINE
+#else
+# define FTS5_NOINLINE
+#endif
+
+/*
+** Write a 64-bit variable-length integer to memory starting at p[0].
+** The length of data write will be between 1 and 9 bytes.  The number
+** of bytes written is returned.
+**
+** A variable-length integer consists of the lower 7 bits of each byte
+** for all bytes that have the 8th bit set and one byte with the 8th
+** bit clear.  Except, if we get to the 9th byte, it stores the full
+** 8 bits and is the last byte.
+*/
+static int FTS5_NOINLINE fts5PutVarint64(unsigned char *p, u64 v){
+  int i, j, n;
+  u8 buf[10];
+  if( v & (((u64)0xff000000)<<32) ){
+    p[8] = (u8)v;
+    v >>= 8;
+    for(i=7; i>=0; i--){
+      p[i] = (u8)((v & 0x7f) | 0x80);
+      v >>= 7;
+    }
+    return 9;
+  }
+  n = 0;
+  do{
+    buf[n++] = (u8)((v & 0x7f) | 0x80);
+    v >>= 7;
+  }while( v!=0 );
+  buf[0] &= 0x7f;
+  assert( n<=9 );
+  for(i=0, j=n-1; j>=0; j--, i++){
+    p[i] = buf[j];
+  }
+  return n;
+}
+
+static int sqlite3Fts5PutVarint(unsigned char *p, u64 v){
+  if( v<=0x7f ){
+    p[0] = v&0x7f;
+    return 1;
+  }
+  if( v<=0x3fff ){
+    p[0] = ((v>>7)&0x7f)|0x80;
+    p[1] = v&0x7f;
+    return 2;
+  }
+  return fts5PutVarint64(p,v);
+}
+
+
+static int sqlite3Fts5GetVarintLen(u32 iVal){
+#if 0
+  if( iVal<(1 << 7 ) ) return 1;
+#endif
+  assert( iVal>=(1 << 7) );
+  if( iVal<(1 << 14) ) return 2;
+  if( iVal<(1 << 21) ) return 3;
+  if( iVal<(1 << 28) ) return 4;
+  return 5;
+}
+
+/*
+** 2015 May 08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This is an SQLite virtual table module implementing direct access to an
+** existing FTS5 index. The module may create several different types of
+** tables:
+**
+** col:
+**     CREATE TABLE vocab(term, col, doc, cnt, PRIMARY KEY(term, col));
+**
+**   One row for each term/column combination. The value of $doc is set to
+**   the number of fts5 rows that contain at least one instance of term
+**   $term within column $col. Field $cnt is set to the total number of
+**   instances of term $term in column $col (in any row of the fts5 table).
+**
+** row:
+**     CREATE TABLE vocab(term, doc, cnt, PRIMARY KEY(term));
+**
+**   One row for each term in the database. The value of $doc is set to
+**   the number of fts5 rows that contain at least one instance of term
+**   $term. Field $cnt is set to the total number of instances of term
+**   $term in the database.
+**
+** instance:
+**     CREATE TABLE vocab(term, doc, col, offset, PRIMARY KEY(<all-fields>));
+**
+**   One row for each term instance in the database.
+*/
+
+
+/* #include "fts5Int.h" */
+
+
+typedef struct Fts5VocabTable Fts5VocabTable;
+typedef struct Fts5VocabCursor Fts5VocabCursor;
+
+struct Fts5VocabTable {
+  sqlite3_vtab base;
+  char *zFts5Tbl;                 /* Name of fts5 table */
+  char *zFts5Db;                  /* Db containing fts5 table */
+  sqlite3 *db;                    /* Database handle */
+  Fts5Global *pGlobal;            /* FTS5 global object for this database */
+  int eType;                      /* FTS5_VOCAB_COL, ROW or INSTANCE */
+  unsigned bBusy;                 /* True if busy */
+};
+
+struct Fts5VocabCursor {
+  sqlite3_vtab_cursor base;
+  sqlite3_stmt *pStmt;            /* Statement holding lock on pIndex */
+  Fts5Table *pFts5;               /* Associated FTS5 table */
+
+  int bEof;                       /* True if this cursor is at EOF */
+  Fts5IndexIter *pIter;           /* Term/rowid iterator object */
+  void *pStruct;                  /* From sqlite3Fts5StructureRef() */
+
+  int nLeTerm;                    /* Size of zLeTerm in bytes */
+  char *zLeTerm;                  /* (term <= $zLeTerm) paramater, or NULL */
+  int colUsed;                    /* Copy of sqlite3_index_info.colUsed */
+
+  /* These are used by 'col' tables only */
+  int iCol;
+  i64 *aCnt;
+  i64 *aDoc;
+
+  /* Output values used by all tables. */
+  i64 rowid;                      /* This table's current rowid value */
+  Fts5Buffer term;                /* Current value of 'term' column */
+
+  /* Output values Used by 'instance' tables only */
+  i64 iInstPos;
+  int iInstOff;
+};
+
+#define FTS5_VOCAB_COL      0
+#define FTS5_VOCAB_ROW      1
+#define FTS5_VOCAB_INSTANCE 2
+
+#define FTS5_VOCAB_COL_SCHEMA  "term, col, doc, cnt"
+#define FTS5_VOCAB_ROW_SCHEMA  "term, doc, cnt"
+#define FTS5_VOCAB_INST_SCHEMA "term, doc, col, offset"
+
+/*
+** Bits for the mask used as the idxNum value by xBestIndex/xFilter.
+*/
+#define FTS5_VOCAB_TERM_EQ 0x0100
+#define FTS5_VOCAB_TERM_GE 0x0200
+#define FTS5_VOCAB_TERM_LE 0x0400
+
+#define FTS5_VOCAB_COLUSED_MASK 0xFF
+
+
+/*
+** Translate a string containing an fts5vocab table type to an
+** FTS5_VOCAB_XXX constant. If successful, set *peType to the output
+** value and return SQLITE_OK. Otherwise, set *pzErr to an error message
+** and return SQLITE_ERROR.
+*/
+static int fts5VocabTableType(const char *zType, char **pzErr, int *peType){
+  int rc = SQLITE_OK;
+  char *zCopy = sqlite3Fts5Strndup(&rc, zType, -1);
+  if( rc==SQLITE_OK ){
+    sqlite3Fts5Dequote(zCopy);
+    if( sqlite3_stricmp(zCopy, "col")==0 ){
+      *peType = FTS5_VOCAB_COL;
+    }else
+
+    if( sqlite3_stricmp(zCopy, "row")==0 ){
+      *peType = FTS5_VOCAB_ROW;
+    }else
+    if( sqlite3_stricmp(zCopy, "instance")==0 ){
+      *peType = FTS5_VOCAB_INSTANCE;
+    }else
+    {
+      *pzErr = sqlite3_mprintf("fts5vocab: unknown table type: %Q", zCopy);
+      rc = SQLITE_ERROR;
+    }
+    sqlite3_free(zCopy);
+  }
+
+  return rc;
+}
+
+
+/*
+** The xDisconnect() virtual table method.
+*/
+static int fts5VocabDisconnectMethod(sqlite3_vtab *pVtab){
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pVtab;
+  sqlite3_free(pTab);
+  return SQLITE_OK;
+}
+
+/*
+** The xDestroy() virtual table method.
+*/
+static int fts5VocabDestroyMethod(sqlite3_vtab *pVtab){
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pVtab;
+  sqlite3_free(pTab);
+  return SQLITE_OK;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the FTS3 virtual table.
+**
+** The argv[] array contains the following:
+**
+**   argv[0]   -> module name  ("fts5vocab")
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**
+** then:
+**
+**   argv[3]   -> name of fts5 table
+**   argv[4]   -> type of fts5vocab table
+**
+** or, for tables in the TEMP schema only.
+**
+**   argv[3]   -> name of fts5 tables database
+**   argv[4]   -> name of fts5 table
+**   argv[5]   -> type of fts5vocab table
+*/
+static int fts5VocabInitVtab(
+  sqlite3 *db,                    /* The SQLite database connection */
+  void *pAux,                     /* Pointer to Fts5Global object */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
+  char **pzErr                    /* Write any error message here */
+){
+  const char *azSchema[] = {
+    "CREATE TABlE vocab(" FTS5_VOCAB_COL_SCHEMA  ")",
+    "CREATE TABlE vocab(" FTS5_VOCAB_ROW_SCHEMA  ")",
+    "CREATE TABlE vocab(" FTS5_VOCAB_INST_SCHEMA ")"
+  };
+
+  Fts5VocabTable *pRet = 0;
+  int rc = SQLITE_OK;             /* Return code */
+  int bDb;
+
+  bDb = (argc==6 && strlen(argv[1])==4 && memcmp("temp", argv[1], 4)==0);
+
+  if( argc!=5 && bDb==0 ){
+    *pzErr = sqlite3_mprintf("wrong number of vtable arguments");
+    rc = SQLITE_ERROR;
+  }else{
+    int nByte;                      /* Bytes of space to allocate */
+    const char *zDb = bDb ? argv[3] : argv[1];
+    const char *zTab = bDb ? argv[4] : argv[3];
+    const char *zType = bDb ? argv[5] : argv[4];
+    int nDb = (int)strlen(zDb)+1;
+    int nTab = (int)strlen(zTab)+1;
+    int eType = 0;
+
+    rc = fts5VocabTableType(zType, pzErr, &eType);
+    if( rc==SQLITE_OK ){
+      assert( eType>=0 && eType<ArraySize(azSchema) );
+      rc = sqlite3_declare_vtab(db, azSchema[eType]);
+    }
+
+    nByte = sizeof(Fts5VocabTable) + nDb + nTab;
+    pRet = sqlite3Fts5MallocZero(&rc, nByte);
+    if( pRet ){
+      pRet->pGlobal = (Fts5Global*)pAux;
+      pRet->eType = eType;
+      pRet->db = db;
+      pRet->zFts5Tbl = (char*)&pRet[1];
+      pRet->zFts5Db = &pRet->zFts5Tbl[nTab];
+      memcpy(pRet->zFts5Tbl, zTab, nTab);
+      memcpy(pRet->zFts5Db, zDb, nDb);
+      sqlite3Fts5Dequote(pRet->zFts5Tbl);
+      sqlite3Fts5Dequote(pRet->zFts5Db);
+    }
+  }
+
+  *ppVTab = (sqlite3_vtab*)pRet;
+  return rc;
+}
+
+
+/*
+** The xConnect() and xCreate() methods for the virtual table. All the
+** work is done in function fts5VocabInitVtab().
+*/
+static int fts5VocabConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5VocabInitVtab(db, pAux, argc, argv, ppVtab, pzErr);
+}
+static int fts5VocabCreateMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5VocabInitVtab(db, pAux, argc, argv, ppVtab, pzErr);
+}
+
+/*
+** Implementation of the xBestIndex method.
+**
+** Only constraints of the form:
+**
+**     term <= ?
+**     term == ?
+**     term >= ?
+**
+** are interpreted. Less-than and less-than-or-equal are treated
+** identically, as are greater-than and greater-than-or-equal.
+*/
+static int fts5VocabBestIndexMethod(
+  sqlite3_vtab *pUnused,
+  sqlite3_index_info *pInfo
+){
+  int i;
+  int iTermEq = -1;
+  int iTermGe = -1;
+  int iTermLe = -1;
+  int idxNum = (int)pInfo->colUsed;
+  int nArg = 0;
+
+  UNUSED_PARAM(pUnused);
+
+  assert( (pInfo->colUsed & FTS5_VOCAB_COLUSED_MASK)==pInfo->colUsed );
+
+  for(i=0; i<pInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *p = &pInfo->aConstraint[i];
+    if( p->usable==0 ) continue;
+    if( p->iColumn==0 ){          /* term column */
+      if( p->op==SQLITE_INDEX_CONSTRAINT_EQ ) iTermEq = i;
+      if( p->op==SQLITE_INDEX_CONSTRAINT_LE ) iTermLe = i;
+      if( p->op==SQLITE_INDEX_CONSTRAINT_LT ) iTermLe = i;
+      if( p->op==SQLITE_INDEX_CONSTRAINT_GE ) iTermGe = i;
+      if( p->op==SQLITE_INDEX_CONSTRAINT_GT ) iTermGe = i;
+    }
+  }
+
+  if( iTermEq>=0 ){
+    idxNum |= FTS5_VOCAB_TERM_EQ;
+    pInfo->aConstraintUsage[iTermEq].argvIndex = ++nArg;
+    pInfo->estimatedCost = 100;
+  }else{
+    pInfo->estimatedCost = 1000000;
+    if( iTermGe>=0 ){
+      idxNum |= FTS5_VOCAB_TERM_GE;
+      pInfo->aConstraintUsage[iTermGe].argvIndex = ++nArg;
+      pInfo->estimatedCost = pInfo->estimatedCost / 2;
+    }
+    if( iTermLe>=0 ){
+      idxNum |= FTS5_VOCAB_TERM_LE;
+      pInfo->aConstraintUsage[iTermLe].argvIndex = ++nArg;
+      pInfo->estimatedCost = pInfo->estimatedCost / 2;
+    }
+  }
+
+  /* This virtual table always delivers results in ascending order of
+  ** the "term" column (column 0). So if the user has requested this
+  ** specifically - "ORDER BY term" or "ORDER BY term ASC" - set the
+  ** sqlite3_index_info.orderByConsumed flag to tell the core the results
+  ** are already in sorted order.  */
+  if( pInfo->nOrderBy==1
+   && pInfo->aOrderBy[0].iColumn==0
+   && pInfo->aOrderBy[0].desc==0
+  ){
+    pInfo->orderByConsumed = 1;
+  }
+
+  pInfo->idxNum = idxNum;
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xOpen method.
+*/
+static int fts5VocabOpenMethod(
+  sqlite3_vtab *pVTab,
+  sqlite3_vtab_cursor **ppCsr
+){
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pVTab;
+  Fts5Table *pFts5 = 0;
+  Fts5VocabCursor *pCsr = 0;
+  int rc = SQLITE_OK;
+  sqlite3_stmt *pStmt = 0;
+  char *zSql = 0;
+
+  if( pTab->bBusy ){
+    pVTab->zErrMsg = sqlite3_mprintf(
+       "recursive definition for %s.%s", pTab->zFts5Db, pTab->zFts5Tbl
+    );
+    return SQLITE_ERROR;
+  }
+  zSql = sqlite3Fts5Mprintf(&rc,
+      "SELECT t.%Q FROM %Q.%Q AS t WHERE t.%Q MATCH '*id'",
+      pTab->zFts5Tbl, pTab->zFts5Db, pTab->zFts5Tbl, pTab->zFts5Tbl
+  );
+  if( zSql ){
+    rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pStmt, 0);
+  }
+  sqlite3_free(zSql);
+  assert( rc==SQLITE_OK || pStmt==0 );
+  if( rc==SQLITE_ERROR ) rc = SQLITE_OK;
+
+  pTab->bBusy = 1;
+  if( pStmt && sqlite3_step(pStmt)==SQLITE_ROW ){
+    i64 iId = sqlite3_column_int64(pStmt, 0);
+    pFts5 = sqlite3Fts5TableFromCsrid(pTab->pGlobal, iId);
+  }
+  pTab->bBusy = 0;
+
+  if( rc==SQLITE_OK ){
+    if( pFts5==0 ){
+      rc = sqlite3_finalize(pStmt);
+      pStmt = 0;
+      if( rc==SQLITE_OK ){
+        pVTab->zErrMsg = sqlite3_mprintf(
+            "no such fts5 table: %s.%s", pTab->zFts5Db, pTab->zFts5Tbl
+        );
+        rc = SQLITE_ERROR;
+      }
+    }else{
+      rc = sqlite3Fts5FlushToDisk(pFts5);
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    i64 nByte = pFts5->pConfig->nCol * sizeof(i64)*2 + sizeof(Fts5VocabCursor);
+    pCsr = (Fts5VocabCursor*)sqlite3Fts5MallocZero(&rc, nByte);
+  }
+
+  if( pCsr ){
+    pCsr->pFts5 = pFts5;
+    pCsr->pStmt = pStmt;
+    pCsr->aCnt = (i64*)&pCsr[1];
+    pCsr->aDoc = &pCsr->aCnt[pFts5->pConfig->nCol];
+  }else{
+    sqlite3_finalize(pStmt);
+  }
+
+  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
+  return rc;
+}
+
+static void fts5VocabResetCursor(Fts5VocabCursor *pCsr){
+  pCsr->rowid = 0;
+  sqlite3Fts5IterClose(pCsr->pIter);
+  sqlite3Fts5StructureRelease(pCsr->pStruct);
+  pCsr->pStruct = 0;
+  pCsr->pIter = 0;
+  sqlite3_free(pCsr->zLeTerm);
+  pCsr->nLeTerm = -1;
+  pCsr->zLeTerm = 0;
+  pCsr->bEof = 0;
+}
+
+/*
+** Close the cursor.  For additional information see the documentation
+** on the xClose method of the virtual table interface.
+*/
+static int fts5VocabCloseMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  fts5VocabResetCursor(pCsr);
+  sqlite3Fts5BufferFree(&pCsr->term);
+  sqlite3_finalize(pCsr->pStmt);
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+static int fts5VocabInstanceNewTerm(Fts5VocabCursor *pCsr){
+  int rc = SQLITE_OK;
+
+  if( sqlite3Fts5IterEof(pCsr->pIter) ){
+    pCsr->bEof = 1;
+  }else{
+    const char *zTerm;
+    int nTerm;
+    zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
+    if( pCsr->nLeTerm>=0 ){
+      int nCmp = MIN(nTerm, pCsr->nLeTerm);
+      int bCmp = memcmp(pCsr->zLeTerm, zTerm, nCmp);
+      if( bCmp<0 || (bCmp==0 && pCsr->nLeTerm<nTerm) ){
+        pCsr->bEof = 1;
+      }
+    }
+
+    sqlite3Fts5BufferSet(&rc, &pCsr->term, nTerm, (const u8*)zTerm);
+  }
+  return rc;
+}
+
+static int fts5VocabInstanceNext(Fts5VocabCursor *pCsr){
+  int eDetail = pCsr->pFts5->pConfig->eDetail;
+  int rc = SQLITE_OK;
+  Fts5IndexIter *pIter = pCsr->pIter;
+  i64 *pp = &pCsr->iInstPos;
+  int *po = &pCsr->iInstOff;
+
+  assert( sqlite3Fts5IterEof(pIter)==0 );
+  assert( pCsr->bEof==0 );
+  while( eDetail==FTS5_DETAIL_NONE
+      || sqlite3Fts5PoslistNext64(pIter->pData, pIter->nData, po, pp)
+  ){
+    pCsr->iInstPos = 0;
+    pCsr->iInstOff = 0;
+
+    rc = sqlite3Fts5IterNextScan(pCsr->pIter);
+    if( rc==SQLITE_OK ){
+      rc = fts5VocabInstanceNewTerm(pCsr);
+      if( pCsr->bEof || eDetail==FTS5_DETAIL_NONE ) break;
+    }
+    if( rc ){
+      pCsr->bEof = 1;
+      break;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Advance the cursor to the next row in the table.
+*/
+static int fts5VocabNextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pCursor->pVtab;
+  int nCol = pCsr->pFts5->pConfig->nCol;
+  int rc;
+
+  rc = sqlite3Fts5StructureTest(pCsr->pFts5->pIndex, pCsr->pStruct);
+  if( rc!=SQLITE_OK ) return rc;
+  pCsr->rowid++;
+
+  if( pTab->eType==FTS5_VOCAB_INSTANCE ){
+    return fts5VocabInstanceNext(pCsr);
+  }
+
+  if( pTab->eType==FTS5_VOCAB_COL ){
+    for(pCsr->iCol++; pCsr->iCol<nCol; pCsr->iCol++){
+      if( pCsr->aDoc[pCsr->iCol] ) break;
+    }
+  }
+
+  if( pTab->eType!=FTS5_VOCAB_COL || pCsr->iCol>=nCol ){
+    if( sqlite3Fts5IterEof(pCsr->pIter) ){
+      pCsr->bEof = 1;
+    }else{
+      const char *zTerm;
+      int nTerm;
+
+      zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
+      assert( nTerm>=0 );
+      if( pCsr->nLeTerm>=0 ){
+        int nCmp = MIN(nTerm, pCsr->nLeTerm);
+        int bCmp = memcmp(pCsr->zLeTerm, zTerm, nCmp);
+        if( bCmp<0 || (bCmp==0 && pCsr->nLeTerm<nTerm) ){
+          pCsr->bEof = 1;
+          return SQLITE_OK;
+        }
+      }
+
+      sqlite3Fts5BufferSet(&rc, &pCsr->term, nTerm, (const u8*)zTerm);
+      memset(pCsr->aCnt, 0, nCol * sizeof(i64));
+      memset(pCsr->aDoc, 0, nCol * sizeof(i64));
+      pCsr->iCol = 0;
+
+      assert( pTab->eType==FTS5_VOCAB_COL || pTab->eType==FTS5_VOCAB_ROW );
+      while( rc==SQLITE_OK ){
+        int eDetail = pCsr->pFts5->pConfig->eDetail;
+        const u8 *pPos; int nPos;   /* Position list */
+        i64 iPos = 0;               /* 64-bit position read from poslist */
+        int iOff = 0;               /* Current offset within position list */
+
+        pPos = pCsr->pIter->pData;
+        nPos = pCsr->pIter->nData;
+
+        switch( pTab->eType ){
+          case FTS5_VOCAB_ROW:
+            /* Do not bother counting the number of instances if the "cnt"
+            ** column is not being read (according to colUsed).  */
+            if( eDetail==FTS5_DETAIL_FULL && (pCsr->colUsed & 0x04) ){
+              while( iPos<nPos ){
+                u32 ii;
+                fts5FastGetVarint32(pPos, iPos, ii);
+                if( ii==1 ){
+                  /* New column in the position list */
+                  fts5FastGetVarint32(pPos, iPos, ii);
+                }else{
+                  /* An instance - increment pCsr->aCnt[] */
+                  pCsr->aCnt[0]++;
+                }
+              }
+            }
+            pCsr->aDoc[0]++;
+            break;
+
+          case FTS5_VOCAB_COL:
+            if( eDetail==FTS5_DETAIL_FULL ){
+              int iCol = -1;
+              while( 0==sqlite3Fts5PoslistNext64(pPos, nPos, &iOff, &iPos) ){
+                int ii = FTS5_POS2COLUMN(iPos);
+                if( iCol!=ii ){
+                  if( ii>=nCol ){
+                    rc = FTS5_CORRUPT;
+                    break;
+                  }
+                  pCsr->aDoc[ii]++;
+                  iCol = ii;
+                }
+                pCsr->aCnt[ii]++;
+              }
+            }else if( eDetail==FTS5_DETAIL_COLUMNS ){
+              while( 0==sqlite3Fts5PoslistNext64(pPos, nPos, &iOff,&iPos) ){
+                assert_nc( iPos>=0 && iPos<nCol );
+                if( iPos>=nCol ){
+                  rc = FTS5_CORRUPT;
+                  break;
+                }
+                pCsr->aDoc[iPos]++;
+              }
+            }else{
+              assert( eDetail==FTS5_DETAIL_NONE );
+              pCsr->aDoc[0]++;
+            }
+            break;
+
+          default:
+            assert( pTab->eType==FTS5_VOCAB_INSTANCE );
+            break;
+        }
+
+        if( rc==SQLITE_OK ){
+          rc = sqlite3Fts5IterNextScan(pCsr->pIter);
+        }
+        if( pTab->eType==FTS5_VOCAB_INSTANCE ) break;
+
+        if( rc==SQLITE_OK ){
+          zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
+          if( nTerm!=pCsr->term.n
+          || (nTerm>0 && memcmp(zTerm, pCsr->term.p, nTerm))
+          ){
+            break;
+          }
+          if( sqlite3Fts5IterEof(pCsr->pIter) ) break;
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK && pCsr->bEof==0 && pTab->eType==FTS5_VOCAB_COL ){
+    for(/* noop */; pCsr->iCol<nCol && pCsr->aDoc[pCsr->iCol]==0; pCsr->iCol++);
+    if( pCsr->iCol==nCol ){
+      rc = FTS5_CORRUPT;
+    }
+  }
+  return rc;
+}
+
+/*
+** This is the xFilter implementation for the virtual table.
+*/
+static int fts5VocabFilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *zUnused,            /* Unused */
+  int nUnused,                    /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  Fts5VocabTable *pTab = (Fts5VocabTable*)pCursor->pVtab;
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  int eType = pTab->eType;
+  int rc = SQLITE_OK;
+
+  int iVal = 0;
+  int f = FTS5INDEX_QUERY_SCAN;
+  const char *zTerm = 0;
+  int nTerm = 0;
+
+  sqlite3_value *pEq = 0;
+  sqlite3_value *pGe = 0;
+  sqlite3_value *pLe = 0;
+
+  UNUSED_PARAM2(zUnused, nUnused);
+
+  fts5VocabResetCursor(pCsr);
+  if( idxNum & FTS5_VOCAB_TERM_EQ ) pEq = apVal[iVal++];
+  if( idxNum & FTS5_VOCAB_TERM_GE ) pGe = apVal[iVal++];
+  if( idxNum & FTS5_VOCAB_TERM_LE ) pLe = apVal[iVal++];
+  pCsr->colUsed = (idxNum & FTS5_VOCAB_COLUSED_MASK);
+
+  if( pEq ){
+    zTerm = (const char *)sqlite3_value_text(pEq);
+    nTerm = sqlite3_value_bytes(pEq);
+    f = FTS5INDEX_QUERY_NOTOKENDATA;
+  }else{
+    if( pGe ){
+      zTerm = (const char *)sqlite3_value_text(pGe);
+      nTerm = sqlite3_value_bytes(pGe);
+    }
+    if( pLe ){
+      const char *zCopy = (const char *)sqlite3_value_text(pLe);
+      if( zCopy==0 ) zCopy = "";
+      pCsr->nLeTerm = sqlite3_value_bytes(pLe);
+      pCsr->zLeTerm = sqlite3_malloc(pCsr->nLeTerm+1);
+      if( pCsr->zLeTerm==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        memcpy(pCsr->zLeTerm, zCopy, pCsr->nLeTerm+1);
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    Fts5Index *pIndex = pCsr->pFts5->pIndex;
+    rc = sqlite3Fts5IndexQuery(pIndex, zTerm, nTerm, f, 0, &pCsr->pIter);
+    if( rc==SQLITE_OK ){
+      pCsr->pStruct = sqlite3Fts5StructureRef(pIndex);
+    }
+  }
+  if( rc==SQLITE_OK && eType==FTS5_VOCAB_INSTANCE ){
+    rc = fts5VocabInstanceNewTerm(pCsr);
+  }
+  if( rc==SQLITE_OK && !pCsr->bEof
+   && (eType!=FTS5_VOCAB_INSTANCE
+    || pCsr->pFts5->pConfig->eDetail!=FTS5_DETAIL_NONE)
+  ){
+    rc = fts5VocabNextMethod(pCursor);
+  }
+
+  return rc;
+}
+
+/*
+** This is the xEof method of the virtual table. SQLite calls this
+** routine to find out if it has reached the end of a result set.
+*/
+static int fts5VocabEofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  return pCsr->bEof;
+}
+
+static int fts5VocabColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  int eDetail = pCsr->pFts5->pConfig->eDetail;
+  int eType = ((Fts5VocabTable*)(pCursor->pVtab))->eType;
+  i64 iVal = 0;
+
+  if( iCol==0 ){
+    sqlite3_result_text(
+        pCtx, (const char*)pCsr->term.p, pCsr->term.n, SQLITE_TRANSIENT
+    );
+  }else if( eType==FTS5_VOCAB_COL ){
+    assert( iCol==1 || iCol==2 || iCol==3 );
+    if( iCol==1 ){
+      if( eDetail!=FTS5_DETAIL_NONE ){
+        const char *z = pCsr->pFts5->pConfig->azCol[pCsr->iCol];
+        sqlite3_result_text(pCtx, z, -1, SQLITE_STATIC);
+      }
+    }else if( iCol==2 ){
+      iVal = pCsr->aDoc[pCsr->iCol];
+    }else{
+      iVal = pCsr->aCnt[pCsr->iCol];
+    }
+  }else if( eType==FTS5_VOCAB_ROW ){
+    assert( iCol==1 || iCol==2 );
+    if( iCol==1 ){
+      iVal = pCsr->aDoc[0];
+    }else{
+      iVal = pCsr->aCnt[0];
+    }
+  }else{
+    assert( eType==FTS5_VOCAB_INSTANCE );
+    switch( iCol ){
+      case 1:
+        sqlite3_result_int64(pCtx, pCsr->pIter->iRowid);
+        break;
+      case 2: {
+        int ii = -1;
+        if( eDetail==FTS5_DETAIL_FULL ){
+          ii = FTS5_POS2COLUMN(pCsr->iInstPos);
+        }else if( eDetail==FTS5_DETAIL_COLUMNS ){
+          ii = (int)pCsr->iInstPos;
+        }
+        if( ii>=0 && ii<pCsr->pFts5->pConfig->nCol ){
+          const char *z = pCsr->pFts5->pConfig->azCol[ii];
+          sqlite3_result_text(pCtx, z, -1, SQLITE_STATIC);
+        }
+        break;
+      }
+      default: {
+        assert( iCol==3 );
+        if( eDetail==FTS5_DETAIL_FULL ){
+          int ii = FTS5_POS2OFFSET(pCsr->iInstPos);
+          sqlite3_result_int(pCtx, ii);
+        }
+        break;
+      }
+    }
+  }
+
+  if( iVal>0 ) sqlite3_result_int64(pCtx, iVal);
+  return SQLITE_OK;
+}
+
+/*
+** This is the xRowid method. The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set. The
+** rowid should be written to *pRowid.
+*/
+static int fts5VocabRowidMethod(
+  sqlite3_vtab_cursor *pCursor,
+  sqlite_int64 *pRowid
+){
+  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
+  *pRowid = pCsr->rowid;
+  return SQLITE_OK;
+}
+
+static int sqlite3Fts5VocabInit(Fts5Global *pGlobal, sqlite3 *db){
+  static const sqlite3_module fts5Vocab = {
+    /* iVersion      */ 2,
+    /* xCreate       */ fts5VocabCreateMethod,
+    /* xConnect      */ fts5VocabConnectMethod,
+    /* xBestIndex    */ fts5VocabBestIndexMethod,
+    /* xDisconnect   */ fts5VocabDisconnectMethod,
+    /* xDestroy      */ fts5VocabDestroyMethod,
+    /* xOpen         */ fts5VocabOpenMethod,
+    /* xClose        */ fts5VocabCloseMethod,
+    /* xFilter       */ fts5VocabFilterMethod,
+    /* xNext         */ fts5VocabNextMethod,
+    /* xEof          */ fts5VocabEofMethod,
+    /* xColumn       */ fts5VocabColumnMethod,
+    /* xRowid        */ fts5VocabRowidMethod,
+    /* xUpdate       */ 0,
+    /* xBegin        */ 0,
+    /* xSync         */ 0,
+    /* xCommit       */ 0,
+    /* xRollback     */ 0,
+    /* xFindFunction */ 0,
+    /* xRename       */ 0,
+    /* xSavepoint    */ 0,
+    /* xRelease      */ 0,
+    /* xRollbackTo   */ 0,
+    /* xShadowName   */ 0,
+    /* xIntegrity    */ 0
+  };
+  void *p = (void*)pGlobal;
+
+  return sqlite3_create_module_v2(db, "fts5vocab", &fts5Vocab, p, 0);
+}
+
+
+/* Here ends the fts5.c composite file. */
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS5) */
+
+/************** End of fts5.c ************************************************/
+/************** Begin file stmt.c ********************************************/
+/*
+** 2017-05-31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file demonstrates an eponymous virtual table that returns information
+** about all prepared statements for the database connection.
+**
+** Usage example:
+**
+**     .load ./stmt
+**     .mode line
+**     .header on
+**     SELECT * FROM stmt;
+*/
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_STMTVTAB)
+#if !defined(SQLITEINT_H)
+/* #include "sqlite3ext.h" */
+#endif
+SQLITE_EXTENSION_INIT1
+/* #include <assert.h> */
+/* #include <string.h> */
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+
+
+#define STMT_NUM_INTEGER_COLUMN 10
+typedef struct StmtRow StmtRow;
+struct StmtRow {
+  sqlite3_int64 iRowid;                /* Rowid value */
+  char *zSql;                          /* column "sql" */
+  int aCol[STMT_NUM_INTEGER_COLUMN+1]; /* all other column values */
+  StmtRow *pNext;                      /* Next row to return */
+};
+
+/* stmt_vtab is a subclass of sqlite3_vtab which will
+** serve as the underlying representation of a stmt virtual table
+*/
+typedef struct stmt_vtab stmt_vtab;
+struct stmt_vtab {
+  sqlite3_vtab base;  /* Base class - must be first */
+  sqlite3 *db;        /* Database connection for this stmt vtab */
+};
+
+/* stmt_cursor is a subclass of sqlite3_vtab_cursor which will
+** serve as the underlying representation of a cursor that scans
+** over rows of the result
+*/
+typedef struct stmt_cursor stmt_cursor;
+struct stmt_cursor {
+  sqlite3_vtab_cursor base;  /* Base class - must be first */
+  sqlite3 *db;               /* Database connection for this cursor */
+  StmtRow *pRow;             /* Current row */
+};
+
+/*
+** The stmtConnect() method is invoked to create a new
+** stmt_vtab that describes the stmt virtual table.
+**
+** Think of this routine as the constructor for stmt_vtab objects.
+**
+** All this routine needs to do is:
+**
+**    (1) Allocate the stmt_vtab object and initialize all fields.
+**
+**    (2) Tell SQLite (via the sqlite3_declare_vtab() interface) what the
+**        result set of queries against stmt will look like.
+*/
+static int stmtConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  stmt_vtab *pNew;
+  int rc;
+
+/* Column numbers */
+#define STMT_COLUMN_SQL     0   /* SQL for the statement */
+#define STMT_COLUMN_NCOL    1   /* Number of result columns */
+#define STMT_COLUMN_RO      2   /* True if read-only */
+#define STMT_COLUMN_BUSY    3   /* True if currently busy */
+#define STMT_COLUMN_NSCAN   4   /* SQLITE_STMTSTATUS_FULLSCAN_STEP */
+#define STMT_COLUMN_NSORT   5   /* SQLITE_STMTSTATUS_SORT */
+#define STMT_COLUMN_NAIDX   6   /* SQLITE_STMTSTATUS_AUTOINDEX */
+#define STMT_COLUMN_NSTEP   7   /* SQLITE_STMTSTATUS_VM_STEP */
+#define STMT_COLUMN_REPREP  8   /* SQLITE_STMTSTATUS_REPREPARE */
+#define STMT_COLUMN_RUN     9   /* SQLITE_STMTSTATUS_RUN */
+#define STMT_COLUMN_MEM    10   /* SQLITE_STMTSTATUS_MEMUSED */
+
+
+  (void)pAux;
+  (void)argc;
+  (void)argv;
+  (void)pzErr;
+  rc = sqlite3_declare_vtab(db,
+     "CREATE TABLE x(sql,ncol,ro,busy,nscan,nsort,naidx,nstep,"
+                    "reprep,run,mem)");
+  if( rc==SQLITE_OK ){
+    pNew = sqlite3_malloc64( sizeof(*pNew) );
+    *ppVtab = (sqlite3_vtab*)pNew;
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, sizeof(*pNew));
+    pNew->db = db;
+  }
+  return rc;
+}
+
+/*
+** This method is the destructor for stmt_cursor objects.
+*/
+static int stmtDisconnect(sqlite3_vtab *pVtab){
+  sqlite3_free(pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** Constructor for a new stmt_cursor object.
+*/
+static int stmtOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
+  stmt_cursor *pCur;
+  pCur = sqlite3_malloc64( sizeof(*pCur) );
+  if( pCur==0 ) return SQLITE_NOMEM;
+  memset(pCur, 0, sizeof(*pCur));
+  pCur->db = ((stmt_vtab*)p)->db;
+  *ppCursor = &pCur->base;
+  return SQLITE_OK;
+}
+
+static void stmtCsrReset(stmt_cursor *pCur){
+  StmtRow *pRow = 0;
+  StmtRow *pNext = 0;
+  for(pRow=pCur->pRow; pRow; pRow=pNext){
+    pNext = pRow->pNext;
+    sqlite3_free(pRow);
+  }
+  pCur->pRow = 0;
+}
+
+/*
+** Destructor for a stmt_cursor.
+*/
+static int stmtClose(sqlite3_vtab_cursor *cur){
+  stmtCsrReset((stmt_cursor*)cur);
+  sqlite3_free(cur);
+  return SQLITE_OK;
+}
+
+
+/*
+** Advance a stmt_cursor to its next row of output.
+*/
+static int stmtNext(sqlite3_vtab_cursor *cur){
+  stmt_cursor *pCur = (stmt_cursor*)cur;
+  StmtRow *pNext = pCur->pRow->pNext;
+  sqlite3_free(pCur->pRow);
+  pCur->pRow = pNext;
+  return SQLITE_OK;
+}
+
+/*
+** Return values of columns for the row at which the stmt_cursor
+** is currently pointing.
+*/
+static int stmtColumn(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int i                       /* Which column to return */
+){
+  stmt_cursor *pCur = (stmt_cursor*)cur;
+  StmtRow *pRow = pCur->pRow;
+  if( i==STMT_COLUMN_SQL ){
+    sqlite3_result_text(ctx, pRow->zSql, -1, SQLITE_TRANSIENT);
+  }else{
+    sqlite3_result_int(ctx, pRow->aCol[i]);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Return the rowid for the current row.  In this implementation, the
+** rowid is the same as the output value.
+*/
+static int stmtRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
+  stmt_cursor *pCur = (stmt_cursor*)cur;
+  *pRowid = pCur->pRow->iRowid;
+  return SQLITE_OK;
+}
+
+/*
+** Return TRUE if the cursor has been moved off of the last
+** row of output.
+*/
+static int stmtEof(sqlite3_vtab_cursor *cur){
+  stmt_cursor *pCur = (stmt_cursor*)cur;
+  return pCur->pRow==0;
+}
+
+/*
+** This method is called to "rewind" the stmt_cursor object back
+** to the first row of output.  This method is always called at least
+** once prior to any call to stmtColumn() or stmtRowid() or
+** stmtEof().
+*/
+static int stmtFilter(
+  sqlite3_vtab_cursor *pVtabCursor,
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  stmt_cursor *pCur = (stmt_cursor *)pVtabCursor;
+  sqlite3_stmt *p = 0;
+  sqlite3_int64 iRowid = 1;
+  StmtRow **ppRow = 0;
+
+  (void)idxNum;
+  (void)idxStr;
+  (void)argc;
+  (void)argv;
+  stmtCsrReset(pCur);
+  ppRow = &pCur->pRow;
+  for(p=sqlite3_next_stmt(pCur->db, 0); p; p=sqlite3_next_stmt(pCur->db, p)){
+    const char *zSql = sqlite3_sql(p);
+    sqlite3_int64 nSql = zSql ? strlen(zSql)+1 : 0;
+    StmtRow *pNew = (StmtRow*)sqlite3_malloc64(sizeof(StmtRow) + nSql);
+
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, sizeof(StmtRow));
+    if( zSql ){
+      pNew->zSql = (char*)&pNew[1];
+      memcpy(pNew->zSql, zSql, nSql);
+    }
+    pNew->aCol[STMT_COLUMN_NCOL] = sqlite3_column_count(p);
+    pNew->aCol[STMT_COLUMN_RO] = sqlite3_stmt_readonly(p);
+    pNew->aCol[STMT_COLUMN_BUSY] = sqlite3_stmt_busy(p);
+    pNew->aCol[STMT_COLUMN_NSCAN] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_FULLSCAN_STEP, 0
+    );
+    pNew->aCol[STMT_COLUMN_NSORT] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_SORT, 0
+    );
+    pNew->aCol[STMT_COLUMN_NAIDX] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_AUTOINDEX, 0
+    );
+    pNew->aCol[STMT_COLUMN_NSTEP] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_VM_STEP, 0
+    );
+    pNew->aCol[STMT_COLUMN_REPREP] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_REPREPARE, 0
+    );
+    pNew->aCol[STMT_COLUMN_RUN] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_RUN, 0
+    );
+    pNew->aCol[STMT_COLUMN_MEM] = sqlite3_stmt_status(
+        p, SQLITE_STMTSTATUS_MEMUSED, 0
+    );
+    pNew->iRowid = iRowid++;
+    *ppRow = pNew;
+    ppRow = &pNew->pNext;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** SQLite will invoke this method one or more times while planning a query
+** that uses the stmt virtual table.  This routine needs to create
+** a query plan for each invocation and compute an estimated cost for that
+** plan.
+*/
+static int stmtBestIndex(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  (void)tab;
+  pIdxInfo->estimatedCost = (double)500;
+  pIdxInfo->estimatedRows = 500;
+  return SQLITE_OK;
+}
+
+/*
+** This following structure defines all the methods for the
+** stmt virtual table.
+*/
+static sqlite3_module stmtModule = {
+  0,                         /* iVersion */
+  0,                         /* xCreate */
+  stmtConnect,               /* xConnect */
+  stmtBestIndex,             /* xBestIndex */
+  stmtDisconnect,            /* xDisconnect */
+  0,                         /* xDestroy */
+  stmtOpen,                  /* xOpen - open a cursor */
+  stmtClose,                 /* xClose - close a cursor */
+  stmtFilter,                /* xFilter - configure scan constraints */
+  stmtNext,                  /* xNext - advance a cursor */
+  stmtEof,                   /* xEof - check for end of scan */
+  stmtColumn,                /* xColumn - read data */
+  stmtRowid,                 /* xRowid - read data */
+  0,                         /* xUpdate */
+  0,                         /* xBegin */
+  0,                         /* xSync */
+  0,                         /* xCommit */
+  0,                         /* xRollback */
+  0,                         /* xFindMethod */
+  0,                         /* xRename */
+  0,                         /* xSavepoint */
+  0,                         /* xRelease */
+  0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
+  0                          /* xIntegrity */
+};
+
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+SQLITE_PRIVATE int sqlite3StmtVtabInit(sqlite3 *db){
+  int rc = SQLITE_OK;
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  rc = sqlite3_create_module(db, "sqlite_stmt", &stmtModule, 0);
+#endif
+  return rc;
+}
+
+#ifndef SQLITE_CORE
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+SQLITE_API int sqlite3_stmt_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  int rc = SQLITE_OK;
+  SQLITE_EXTENSION_INIT2(pApi);
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  rc = sqlite3StmtVtabInit(db);
+#endif
+  return rc;
+}
+#endif /* SQLITE_CORE */
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_STMTVTAB) */
+
+/************** End of stmt.c ************************************************/
+/* Return the source-id for this library */
+SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
+#endif /* SQLITE_AMALGAMATION */
+/************************** End of sqlite3.c ******************************/
diff --git a/server/node_modules/better-sqlite3/deps/sqlite3/sqlite3.h b/server/node_modules/better-sqlite3/deps/sqlite3/sqlite3.h
new file mode 100644
index 0000000..b536f64
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/sqlite3/sqlite3.h
@@ -0,0 +1,13715 @@
+/*
+** 2001-09-15
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the interface that the SQLite library
+** presents to client programs.  If a C-function, structure, datatype,
+** or constant definition does not appear in this file, then it is
+** not a published API of SQLite, is subject to change without
+** notice, and should not be referenced by programs that use SQLite.
+**
+** Some of the definitions that are in this file are marked as
+** "experimental".  Experimental interfaces are normally new
+** features recently added to SQLite.  We do not anticipate changes
+** to experimental interfaces but reserve the right to make minor changes
+** if experience from use "in the wild" suggest such changes are prudent.
+**
+** The official C-language API documentation for SQLite is derived
+** from comments in this file.  This file is the authoritative source
+** on how SQLite interfaces are supposed to operate.
+**
+** The name of this file under configuration management is "sqlite.h.in".
+** The makefile makes some minor changes to this file (such as inserting
+** the version number) and changes its name to "sqlite3.h" as
+** part of the build process.
+*/
+#ifndef SQLITE3_H
+#define SQLITE3_H
+#include <stdarg.h>     /* Needed for the definition of va_list */
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/*
+** Facilitate override of interface linkage and calling conventions.
+** Be aware that these macros may not be used within this particular
+** translation of the amalgamation and its associated header file.
+**
+** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
+** compiler that the target identifier should have external linkage.
+**
+** The SQLITE_CDECL macro is used to set the calling convention for
+** public functions that accept a variable number of arguments.
+**
+** The SQLITE_APICALL macro is used to set the calling convention for
+** public functions that accept a fixed number of arguments.
+**
+** The SQLITE_STDCALL macro is no longer used and is now deprecated.
+**
+** The SQLITE_CALLBACK macro is used to set the calling convention for
+** function pointers.
+**
+** The SQLITE_SYSAPI macro is used to set the calling convention for
+** functions provided by the operating system.
+**
+** Currently, the SQLITE_CDECL, SQLITE_APICALL, SQLITE_CALLBACK, and
+** SQLITE_SYSAPI macros are used only when building for environments
+** that require non-default calling conventions.
+*/
+#ifndef SQLITE_EXTERN
+# define SQLITE_EXTERN extern
+#endif
+#ifndef SQLITE_API
+# define SQLITE_API
+#endif
+#ifndef SQLITE_CDECL
+# define SQLITE_CDECL
+#endif
+#ifndef SQLITE_APICALL
+# define SQLITE_APICALL
+#endif
+#ifndef SQLITE_STDCALL
+# define SQLITE_STDCALL SQLITE_APICALL
+#endif
+#ifndef SQLITE_CALLBACK
+# define SQLITE_CALLBACK
+#endif
+#ifndef SQLITE_SYSAPI
+# define SQLITE_SYSAPI
+#endif
+
+/*
+** These no-op macros are used in front of interfaces to mark those
+** interfaces as either deprecated or experimental.  New applications
+** should not use deprecated interfaces - they are supported for backwards
+** compatibility only.  Application writers should be aware that
+** experimental interfaces are subject to change in point releases.
+**
+** These macros used to resolve to various kinds of compiler magic that
+** would generate warning messages when they were used.  But that
+** compiler magic ended up generating such a flurry of bug reports
+** that we have taken it all out and gone back to using simple
+** noop macros.
+*/
+#define SQLITE_DEPRECATED
+#define SQLITE_EXPERIMENTAL
+
+/*
+** Ensure these symbols were not defined by some previous header file.
+*/
+#ifdef SQLITE_VERSION
+# undef SQLITE_VERSION
+#endif
+#ifdef SQLITE_VERSION_NUMBER
+# undef SQLITE_VERSION_NUMBER
+#endif
+
+/*
+** CAPI3REF: Compile-Time Library Version Numbers
+**
+** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
+** evaluates to a string literal that is the SQLite version in the
+** format "X.Y.Z" where X is the major version number (always 3 for
+** SQLite3) and Y is the minor version number and Z is the release number.)^
+** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
+** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
+** numbers used in [SQLITE_VERSION].)^
+** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
+** be larger than the release from which it is derived.  Either Y will
+** be held constant and Z will be incremented or else Y will be incremented
+** and Z will be reset to zero.
+**
+** Since [version 3.6.18] ([dateof:3.6.18]),
+** SQLite source code has been stored in the
+** <a href="http://www.fossil-scm.org/">Fossil configuration management
+** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
+** a string which identifies a particular check-in of SQLite
+** within its configuration management system.  ^The SQLITE_SOURCE_ID
+** string contains the date and time of the check-in (UTC) and a SHA1
+** or SHA3-256 hash of the entire source tree.  If the source code has
+** been edited in any way since it was last checked in, then the last
+** four hexadecimal digits of the hash may be modified.
+**
+** See also: [sqlite3_libversion()],
+** [sqlite3_libversion_number()], [sqlite3_sourceid()],
+** [sqlite_version()] and [sqlite_source_id()].
+*/
+#define SQLITE_VERSION        "3.49.2"
+#define SQLITE_VERSION_NUMBER 3049002
+#define SQLITE_SOURCE_ID      "2025-05-07 10:39:52 17144570b0d96ae63cd6f3edca39e27ebd74925252bbaf6723bcb2f6b4861fb1"
+
+/*
+** CAPI3REF: Run-Time Library Version Numbers
+** KEYWORDS: sqlite3_version sqlite3_sourceid
+**
+** These interfaces provide the same information as the [SQLITE_VERSION],
+** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
+** but are associated with the library instead of the header file.  ^(Cautious
+** programmers might include assert() statements in their application to
+** verify that values returned by these interfaces match the macros in
+** the header, and thus ensure that the application is
+** compiled with matching library and header files.
+**
+** <blockquote><pre>
+** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
+** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
+** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
+** </pre></blockquote>)^
+**
+** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
+** macro.  ^The sqlite3_libversion() function returns a pointer to the
+** to the sqlite3_version[] string constant.  The sqlite3_libversion()
+** function is provided for use in DLLs since DLL users usually do not have
+** direct access to string constants within the DLL.  ^The
+** sqlite3_libversion_number() function returns an integer equal to
+** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns
+** a pointer to a string constant whose value is the same as the
+** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
+** using an edited copy of [the amalgamation], then the last four characters
+** of the hash might be different from [SQLITE_SOURCE_ID].)^
+**
+** See also: [sqlite_version()] and [sqlite_source_id()].
+*/
+SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
+SQLITE_API const char *sqlite3_libversion(void);
+SQLITE_API const char *sqlite3_sourceid(void);
+SQLITE_API int sqlite3_libversion_number(void);
+
+/*
+** CAPI3REF: Run-Time Library Compilation Options Diagnostics
+**
+** ^The sqlite3_compileoption_used() function returns 0 or 1
+** indicating whether the specified option was defined at
+** compile time.  ^The SQLITE_ prefix may be omitted from the
+** option name passed to sqlite3_compileoption_used().
+**
+** ^The sqlite3_compileoption_get() function allows iterating
+** over the list of options that were defined at compile time by
+** returning the N-th compile time option string.  ^If N is out of range,
+** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
+** prefix is omitted from any strings returned by
+** sqlite3_compileoption_get().
+**
+** ^Support for the diagnostic functions sqlite3_compileoption_used()
+** and sqlite3_compileoption_get() may be omitted by specifying the
+** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
+**
+** See also: SQL functions [sqlite_compileoption_used()] and
+** [sqlite_compileoption_get()] and the [compile_options pragma].
+*/
+#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
+SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
+SQLITE_API const char *sqlite3_compileoption_get(int N);
+#else
+# define sqlite3_compileoption_used(X) 0
+# define sqlite3_compileoption_get(X)  ((void*)0)
+#endif
+
+/*
+** CAPI3REF: Test To See If The Library Is Threadsafe
+**
+** ^The sqlite3_threadsafe() function returns zero if and only if
+** SQLite was compiled with mutexing code omitted due to the
+** [SQLITE_THREADSAFE] compile-time option being set to 0.
+**
+** SQLite can be compiled with or without mutexes.  When
+** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
+** are enabled and SQLite is threadsafe.  When the
+** [SQLITE_THREADSAFE] macro is 0,
+** the mutexes are omitted.  Without the mutexes, it is not safe
+** to use SQLite concurrently from more than one thread.
+**
+** Enabling mutexes incurs a measurable performance penalty.
+** So if speed is of utmost importance, it makes sense to disable
+** the mutexes.  But for maximum safety, mutexes should be enabled.
+** ^The default behavior is for mutexes to be enabled.
+**
+** This interface can be used by an application to make sure that the
+** version of SQLite that it is linking against was compiled with
+** the desired setting of the [SQLITE_THREADSAFE] macro.
+**
+** This interface only reports on the compile-time mutex setting
+** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
+** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
+** can be fully or partially disabled using a call to [sqlite3_config()]
+** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
+** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
+** sqlite3_threadsafe() function shows only the compile-time setting of
+** thread safety, not any run-time changes to that setting made by
+** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
+** is unchanged by calls to sqlite3_config().)^
+**
+** See the [threading mode] documentation for additional information.
+*/
+SQLITE_API int sqlite3_threadsafe(void);
+
+/*
+** CAPI3REF: Database Connection Handle
+** KEYWORDS: {database connection} {database connections}
+**
+** Each open SQLite database is represented by a pointer to an instance of
+** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
+** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
+** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
+** and [sqlite3_close_v2()] are its destructors.  There are many other
+** interfaces (such as
+** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
+** [sqlite3_busy_timeout()] to name but three) that are methods on an
+** sqlite3 object.
+*/
+typedef struct sqlite3 sqlite3;
+
+/*
+** CAPI3REF: 64-Bit Integer Types
+** KEYWORDS: sqlite_int64 sqlite_uint64
+**
+** Because there is no cross-platform way to specify 64-bit integer types
+** SQLite includes typedefs for 64-bit signed and unsigned integers.
+**
+** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
+** The sqlite_int64 and sqlite_uint64 types are supported for backwards
+** compatibility only.
+**
+** ^The sqlite3_int64 and sqlite_int64 types can store integer values
+** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
+** sqlite3_uint64 and sqlite_uint64 types can store integer values
+** between 0 and +18446744073709551615 inclusive.
+*/
+#ifdef SQLITE_INT64_TYPE
+  typedef SQLITE_INT64_TYPE sqlite_int64;
+# ifdef SQLITE_UINT64_TYPE
+    typedef SQLITE_UINT64_TYPE sqlite_uint64;
+# else
+    typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
+# endif
+#elif defined(_MSC_VER) || defined(__BORLANDC__)
+  typedef __int64 sqlite_int64;
+  typedef unsigned __int64 sqlite_uint64;
+#else
+  typedef long long int sqlite_int64;
+  typedef unsigned long long int sqlite_uint64;
+#endif
+typedef sqlite_int64 sqlite3_int64;
+typedef sqlite_uint64 sqlite3_uint64;
+
+/*
+** If compiling for a processor that lacks floating point support,
+** substitute integer for floating-point.
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# define double sqlite3_int64
+#endif
+
+/*
+** CAPI3REF: Closing A Database Connection
+** DESTRUCTOR: sqlite3
+**
+** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
+** for the [sqlite3] object.
+** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
+** the [sqlite3] object is successfully destroyed and all associated
+** resources are deallocated.
+**
+** Ideally, applications should [sqlite3_finalize | finalize] all
+** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
+** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
+** with the [sqlite3] object prior to attempting to close the object.
+** ^If the database connection is associated with unfinalized prepared
+** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
+** sqlite3_close() will leave the database connection open and return
+** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
+** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
+** it returns [SQLITE_OK] regardless, but instead of deallocating the database
+** connection immediately, it marks the database connection as an unusable
+** "zombie" and makes arrangements to automatically deallocate the database
+** connection after all prepared statements are finalized, all BLOB handles
+** are closed, and all backups have finished. The sqlite3_close_v2() interface
+** is intended for use with host languages that are garbage collected, and
+** where the order in which destructors are called is arbitrary.
+**
+** ^If an [sqlite3] object is destroyed while a transaction is open,
+** the transaction is automatically rolled back.
+**
+** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
+** must be either a NULL
+** pointer or an [sqlite3] object pointer obtained
+** from [sqlite3_open()], [sqlite3_open16()], or
+** [sqlite3_open_v2()], and not previously closed.
+** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
+** argument is a harmless no-op.
+*/
+SQLITE_API int sqlite3_close(sqlite3*);
+SQLITE_API int sqlite3_close_v2(sqlite3*);
+
+/*
+** The type for a callback function.
+** This is legacy and deprecated.  It is included for historical
+** compatibility and is not documented.
+*/
+typedef int (*sqlite3_callback)(void*,int,char**, char**);
+
+/*
+** CAPI3REF: One-Step Query Execution Interface
+** METHOD: sqlite3
+**
+** The sqlite3_exec() interface is a convenience wrapper around
+** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
+** that allows an application to run multiple statements of SQL
+** without having to use a lot of C code.
+**
+** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
+** semicolon-separate SQL statements passed into its 2nd argument,
+** in the context of the [database connection] passed in as its 1st
+** argument.  ^If the callback function of the 3rd argument to
+** sqlite3_exec() is not NULL, then it is invoked for each result row
+** coming out of the evaluated SQL statements.  ^The 4th argument to
+** sqlite3_exec() is relayed through to the 1st argument of each
+** callback invocation.  ^If the callback pointer to sqlite3_exec()
+** is NULL, then no callback is ever invoked and result rows are
+** ignored.
+**
+** ^If an error occurs while evaluating the SQL statements passed into
+** sqlite3_exec(), then execution of the current statement stops and
+** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
+** is not NULL then any error message is written into memory obtained
+** from [sqlite3_malloc()] and passed back through the 5th parameter.
+** To avoid memory leaks, the application should invoke [sqlite3_free()]
+** on error message strings returned through the 5th parameter of
+** sqlite3_exec() after the error message string is no longer needed.
+** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
+** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
+** NULL before returning.
+**
+** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
+** routine returns SQLITE_ABORT without invoking the callback again and
+** without running any subsequent SQL statements.
+**
+** ^The 2nd argument to the sqlite3_exec() callback function is the
+** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
+** callback is an array of pointers to strings obtained as if from
+** [sqlite3_column_text()], one for each column.  ^If an element of a
+** result row is NULL then the corresponding string pointer for the
+** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
+** sqlite3_exec() callback is an array of pointers to strings where each
+** entry represents the name of corresponding result column as obtained
+** from [sqlite3_column_name()].
+**
+** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
+** to an empty string, or a pointer that contains only whitespace and/or
+** SQL comments, then no SQL statements are evaluated and the database
+** is not changed.
+**
+** Restrictions:
+**
+** <ul>
+** <li> The application must ensure that the 1st parameter to sqlite3_exec()
+**      is a valid and open [database connection].
+** <li> The application must not close the [database connection] specified by
+**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not modify the SQL statement text passed into
+**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
+** <li> The application must not dereference the arrays or string pointers
+**       passed as the 3rd and 4th callback parameters after it returns.
+** </ul>
+*/
+SQLITE_API int sqlite3_exec(
+  sqlite3*,                                  /* An open database */
+  const char *sql,                           /* SQL to be evaluated */
+  int (*callback)(void*,int,char**,char**),  /* Callback function */
+  void *,                                    /* 1st argument to callback */
+  char **errmsg                              /* Error msg written here */
+);
+
+/*
+** CAPI3REF: Result Codes
+** KEYWORDS: {result code definitions}
+**
+** Many SQLite functions return an integer result code from the set shown
+** here in order to indicate success or failure.
+**
+** New error codes may be added in future versions of SQLite.
+**
+** See also: [extended result code definitions]
+*/
+#define SQLITE_OK           0   /* Successful result */
+/* beginning-of-error-codes */
+#define SQLITE_ERROR        1   /* Generic error */
+#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
+#define SQLITE_PERM         3   /* Access permission denied */
+#define SQLITE_ABORT        4   /* Callback routine requested an abort */
+#define SQLITE_BUSY         5   /* The database file is locked */
+#define SQLITE_LOCKED       6   /* A table in the database is locked */
+#define SQLITE_NOMEM        7   /* A malloc() failed */
+#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
+#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
+#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
+#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
+#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
+#define SQLITE_FULL        13   /* Insertion failed because database is full */
+#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
+#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
+#define SQLITE_EMPTY       16   /* Internal use only */
+#define SQLITE_SCHEMA      17   /* The database schema changed */
+#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
+#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
+#define SQLITE_MISMATCH    20   /* Data type mismatch */
+#define SQLITE_MISUSE      21   /* Library used incorrectly */
+#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
+#define SQLITE_AUTH        23   /* Authorization denied */
+#define SQLITE_FORMAT      24   /* Not used */
+#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
+#define SQLITE_NOTADB      26   /* File opened that is not a database file */
+#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
+#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
+#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
+#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
+/* end-of-error-codes */
+
+/*
+** CAPI3REF: Extended Result Codes
+** KEYWORDS: {extended result code definitions}
+**
+** In its default configuration, SQLite API routines return one of 30 integer
+** [result codes].  However, experience has shown that many of
+** these result codes are too coarse-grained.  They do not provide as
+** much information about problems as programmers might like.  In an effort to
+** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
+** and later) include
+** support for additional result codes that provide more detailed information
+** about errors. These [extended result codes] are enabled or disabled
+** on a per database connection basis using the
+** [sqlite3_extended_result_codes()] API.  Or, the extended code for
+** the most recent error can be obtained using
+** [sqlite3_extended_errcode()].
+*/
+#define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
+#define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
+#define SQLITE_ERROR_SNAPSHOT          (SQLITE_ERROR | (3<<8))
+#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
+#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
+#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
+#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
+#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
+#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
+#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
+#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
+#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
+#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
+#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
+#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
+#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
+#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
+#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
+#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
+#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
+#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
+#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
+#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
+#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
+#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
+#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
+#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
+#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
+#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
+#define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
+#define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
+#define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
+#define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
+#define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
+#define SQLITE_IOERR_DATA              (SQLITE_IOERR | (32<<8))
+#define SQLITE_IOERR_CORRUPTFS         (SQLITE_IOERR | (33<<8))
+#define SQLITE_IOERR_IN_PAGE           (SQLITE_IOERR | (34<<8))
+#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
+#define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
+#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
+#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
+#define SQLITE_BUSY_TIMEOUT            (SQLITE_BUSY   |  (3<<8))
+#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
+#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
+#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
+#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
+#define SQLITE_CANTOPEN_DIRTYWAL       (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
+#define SQLITE_CANTOPEN_SYMLINK        (SQLITE_CANTOPEN | (6<<8))
+#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
+#define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
+#define SQLITE_CORRUPT_INDEX           (SQLITE_CORRUPT | (3<<8))
+#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
+#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
+#define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
+#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
+#define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
+#define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
+#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
+#define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
+#define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
+#define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
+#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
+#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
+#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
+#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
+#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
+#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
+#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
+#define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
+#define SQLITE_CONSTRAINT_DATATYPE     (SQLITE_CONSTRAINT |(12<<8))
+#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
+#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
+#define SQLITE_NOTICE_RBU              (SQLITE_NOTICE | (3<<8))
+#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
+#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
+#define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
+#define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8)) /* internal use only */
+
+/*
+** CAPI3REF: Flags For File Open Operations
+**
+** These bit values are intended for use in the
+** 3rd parameter to the [sqlite3_open_v2()] interface and
+** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
+**
+** Only those flags marked as "Ok for sqlite3_open_v2()" may be
+** used as the third argument to the [sqlite3_open_v2()] interface.
+** The other flags have historically been ignored by sqlite3_open_v2(),
+** though future versions of SQLite might change so that an error is
+** raised if any of the disallowed bits are passed into sqlite3_open_v2().
+** Applications should not depend on the historical behavior.
+**
+** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
+** [sqlite3_open_v2()] does *not* cause the underlying database file
+** to be opened using O_EXCL.  Passing SQLITE_OPEN_EXCLUSIVE into
+** [sqlite3_open_v2()] has historically be a no-op and might become an
+** error in future versions of SQLite.
+*/
+#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
+#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
+#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
+#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
+#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
+#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
+#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
+#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
+#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
+#define SQLITE_OPEN_SUPER_JOURNAL    0x00004000  /* VFS only */
+#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
+#define SQLITE_OPEN_NOFOLLOW         0x01000000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_EXRESCODE        0x02000000  /* Extended result codes */
+
+/* Reserved:                         0x00F00000 */
+/* Legacy compatibility: */
+#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
+
+
+/*
+** CAPI3REF: Device Characteristics
+**
+** The xDeviceCharacteristics method of the [sqlite3_io_methods]
+** object returns an integer which is a vector of these
+** bit values expressing I/O characteristics of the mass storage
+** device that holds the file that the [sqlite3_io_methods]
+** refers to.
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
+** after reboot following a crash or power loss, the only bytes in a
+** file that were written at the application level might have changed
+** and that adjacent bytes, even bytes within the same sector are
+** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
+** flag indicates that a file cannot be deleted when open.  The
+** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
+** read-only media and cannot be changed even by processes with
+** elevated privileges.
+**
+** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
+** filesystem supports doing multiple write operations atomically when those
+** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
+** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
+**
+** The SQLITE_IOCAP_SUBPAGE_READ property means that it is ok to read
+** from the database file in amounts that are not a multiple of the
+** page size and that do not begin at a page boundary.  Without this
+** property, SQLite is careful to only do full-page reads and write
+** on aligned pages, with the one exception that it will do a sub-page
+** read of the first page to access the database header.
+*/
+#define SQLITE_IOCAP_ATOMIC                 0x00000001
+#define SQLITE_IOCAP_ATOMIC512              0x00000002
+#define SQLITE_IOCAP_ATOMIC1K               0x00000004
+#define SQLITE_IOCAP_ATOMIC2K               0x00000008
+#define SQLITE_IOCAP_ATOMIC4K               0x00000010
+#define SQLITE_IOCAP_ATOMIC8K               0x00000020
+#define SQLITE_IOCAP_ATOMIC16K              0x00000040
+#define SQLITE_IOCAP_ATOMIC32K              0x00000080
+#define SQLITE_IOCAP_ATOMIC64K              0x00000100
+#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
+#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
+#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
+#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
+#define SQLITE_IOCAP_IMMUTABLE              0x00002000
+#define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
+#define SQLITE_IOCAP_SUBPAGE_READ           0x00008000
+
+/*
+** CAPI3REF: File Locking Levels
+**
+** SQLite uses one of these integer values as the second
+** argument to calls it makes to the xLock() and xUnlock() methods
+** of an [sqlite3_io_methods] object.  These values are ordered from
+** lest restrictive to most restrictive.
+**
+** The argument to xLock() is always SHARED or higher.  The argument to
+** xUnlock is either SHARED or NONE.
+*/
+#define SQLITE_LOCK_NONE          0       /* xUnlock() only */
+#define SQLITE_LOCK_SHARED        1       /* xLock() or xUnlock() */
+#define SQLITE_LOCK_RESERVED      2       /* xLock() only */
+#define SQLITE_LOCK_PENDING       3       /* xLock() only */
+#define SQLITE_LOCK_EXCLUSIVE     4       /* xLock() only */
+
+/*
+** CAPI3REF: Synchronization Type Flags
+**
+** When SQLite invokes the xSync() method of an
+** [sqlite3_io_methods] object it uses a combination of
+** these integer values as the second argument.
+**
+** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
+** sync operation only needs to flush data to mass storage.  Inode
+** information need not be flushed. If the lower four bits of the flag
+** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
+** If the lower four bits equal SQLITE_SYNC_FULL, that means
+** to use Mac OS X style fullsync instead of fsync().
+**
+** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
+** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
+** settings.  The [synchronous pragma] determines when calls to the
+** xSync VFS method occur and applies uniformly across all platforms.
+** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
+** energetic or rigorous or forceful the sync operations are and
+** only make a difference on Mac OSX for the default SQLite code.
+** (Third-party VFS implementations might also make the distinction
+** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
+** operating systems natively supported by SQLite, only Mac OSX
+** cares about the difference.)
+*/
+#define SQLITE_SYNC_NORMAL        0x00002
+#define SQLITE_SYNC_FULL          0x00003
+#define SQLITE_SYNC_DATAONLY      0x00010
+
+/*
+** CAPI3REF: OS Interface Open File Handle
+**
+** An [sqlite3_file] object represents an open file in the
+** [sqlite3_vfs | OS interface layer].  Individual OS interface
+** implementations will
+** want to subclass this object by appending additional fields
+** for their own use.  The pMethods entry is a pointer to an
+** [sqlite3_io_methods] object that defines methods for performing
+** I/O operations on the open file.
+*/
+typedef struct sqlite3_file sqlite3_file;
+struct sqlite3_file {
+  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
+};
+
+/*
+** CAPI3REF: OS Interface File Virtual Methods Object
+**
+** Every file opened by the [sqlite3_vfs.xOpen] method populates an
+** [sqlite3_file] object (or, more commonly, a subclass of the
+** [sqlite3_file] object) with a pointer to an instance of this object.
+** This object defines the methods used to perform various operations
+** against the open file represented by the [sqlite3_file] object.
+**
+** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
+** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
+** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
+** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
+** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
+** to NULL.
+**
+** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
+** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
+** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
+** flag may be ORed in to indicate that only the data of the file
+** and not its inode needs to be synced.
+**
+** The integer values to xLock() and xUnlock() are one of
+** <ul>
+** <li> [SQLITE_LOCK_NONE],
+** <li> [SQLITE_LOCK_SHARED],
+** <li> [SQLITE_LOCK_RESERVED],
+** <li> [SQLITE_LOCK_PENDING], or
+** <li> [SQLITE_LOCK_EXCLUSIVE].
+** </ul>
+** xLock() upgrades the database file lock.  In other words, xLock() moves the
+** database file lock in the direction NONE toward EXCLUSIVE. The argument to
+** xLock() is always one of SHARED, RESERVED, PENDING, or EXCLUSIVE, never
+** SQLITE_LOCK_NONE.  If the database file lock is already at or above the
+** requested lock, then the call to xLock() is a no-op.
+** xUnlock() downgrades the database file lock to either SHARED or NONE.
+** If the lock is already at or below the requested lock state, then the call
+** to xUnlock() is a no-op.
+** The xCheckReservedLock() method checks whether any database connection,
+** either in this process or in some other process, is holding a RESERVED,
+** PENDING, or EXCLUSIVE lock on the file.  It returns, via its output
+** pointer parameter, true if such a lock exists and false otherwise.
+**
+** The xFileControl() method is a generic interface that allows custom
+** VFS implementations to directly control an open file using the
+** [sqlite3_file_control()] interface.  The second "op" argument is an
+** integer opcode.  The third argument is a generic pointer intended to
+** point to a structure that may contain arguments or space in which to
+** write return values.  Potential uses for xFileControl() might be
+** functions to enable blocking locks with timeouts, to change the
+** locking strategy (for example to use dot-file locks), to inquire
+** about the status of a lock, or to break stale locks.  The SQLite
+** core reserves all opcodes less than 100 for its own use.
+** A [file control opcodes | list of opcodes] less than 100 is available.
+** Applications that define a custom xFileControl method should use opcodes
+** greater than 100 to avoid conflicts.  VFS implementations should
+** return [SQLITE_NOTFOUND] for file control opcodes that they do not
+** recognize.
+**
+** The xSectorSize() method returns the sector size of the
+** device that underlies the file.  The sector size is the
+** minimum write that can be performed without disturbing
+** other bytes in the file.  The xDeviceCharacteristics()
+** method returns a bit vector describing behaviors of the
+** underlying device:
+**
+** <ul>
+** <li> [SQLITE_IOCAP_ATOMIC]
+** <li> [SQLITE_IOCAP_ATOMIC512]
+** <li> [SQLITE_IOCAP_ATOMIC1K]
+** <li> [SQLITE_IOCAP_ATOMIC2K]
+** <li> [SQLITE_IOCAP_ATOMIC4K]
+** <li> [SQLITE_IOCAP_ATOMIC8K]
+** <li> [SQLITE_IOCAP_ATOMIC16K]
+** <li> [SQLITE_IOCAP_ATOMIC32K]
+** <li> [SQLITE_IOCAP_ATOMIC64K]
+** <li> [SQLITE_IOCAP_SAFE_APPEND]
+** <li> [SQLITE_IOCAP_SEQUENTIAL]
+** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
+** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
+** <li> [SQLITE_IOCAP_IMMUTABLE]
+** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
+** <li> [SQLITE_IOCAP_SUBPAGE_READ]
+** </ul>
+**
+** The SQLITE_IOCAP_ATOMIC property means that all writes of
+** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
+** mean that writes of blocks that are nnn bytes in size and
+** are aligned to an address which is an integer multiple of
+** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
+** that when data is appended to a file, the data is appended
+** first then the size of the file is extended, never the other
+** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
+** information is written to disk in the same order as calls
+** to xWrite().
+**
+** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
+** in the unread portions of the buffer with zeros.  A VFS that
+** fails to zero-fill short reads might seem to work.  However,
+** failure to zero-fill short reads will eventually lead to
+** database corruption.
+*/
+typedef struct sqlite3_io_methods sqlite3_io_methods;
+struct sqlite3_io_methods {
+  int iVersion;
+  int (*xClose)(sqlite3_file*);
+  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
+  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
+  int (*xSync)(sqlite3_file*, int flags);
+  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
+  int (*xLock)(sqlite3_file*, int);
+  int (*xUnlock)(sqlite3_file*, int);
+  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
+  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
+  int (*xSectorSize)(sqlite3_file*);
+  int (*xDeviceCharacteristics)(sqlite3_file*);
+  /* Methods above are valid for version 1 */
+  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
+  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
+  void (*xShmBarrier)(sqlite3_file*);
+  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
+  /* Methods above are valid for version 2 */
+  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
+  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
+  /* Methods above are valid for version 3 */
+  /* Additional methods may be added in future releases */
+};
+
+/*
+** CAPI3REF: Standard File Control Opcodes
+** KEYWORDS: {file control opcodes} {file control opcode}
+**
+** These integer constants are opcodes for the xFileControl method
+** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
+** interface.
+**
+** <ul>
+** <li>[[SQLITE_FCNTL_LOCKSTATE]]
+** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
+** opcode causes the xFileControl method to write the current state of
+** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
+** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
+** into an integer that the pArg argument points to.
+** This capability is only available if SQLite is compiled with [SQLITE_DEBUG].
+**
+** <li>[[SQLITE_FCNTL_SIZE_HINT]]
+** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
+** layer a hint of how large the database file will grow to be during the
+** current transaction.  This hint is not guaranteed to be accurate but it
+** is often close.  The underlying VFS might choose to preallocate database
+** file space based on this hint in order to help writes to the database
+** file run faster.
+**
+** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
+** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
+** implements [sqlite3_deserialize()] to set an upper bound on the size
+** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
+** If the integer pointed to is negative, then it is filled in with the
+** current limit.  Otherwise the limit is set to the larger of the value
+** of the integer pointed to and the current database size.  The integer
+** pointed to is set to the new limit.
+**
+** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
+** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
+** extends and truncates the database file in chunks of a size specified
+** by the user. The fourth argument to [sqlite3_file_control()] should
+** point to an integer (type int) containing the new chunk-size to use
+** for the nominated database. Allocating database file space in large
+** chunks (say 1MB at a time), may reduce file-system fragmentation and
+** improve performance on some systems.
+**
+** <li>[[SQLITE_FCNTL_FILE_POINTER]]
+** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with a particular database
+** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
+**
+** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
+** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
+** to the [sqlite3_file] object associated with the journal file (either
+** the [rollback journal] or the [write-ahead log]) for a particular database
+** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
+**
+** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
+** No longer in use.
+**
+** <li>[[SQLITE_FCNTL_SYNC]]
+** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
+** sent to the VFS immediately before the xSync method is invoked on a
+** database file descriptor. Or, if the xSync method is not invoked
+** because the user has configured SQLite with
+** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
+** of the xSync method. In most cases, the pointer argument passed with
+** this file-control is NULL. However, if the database file is being synced
+** as part of a multi-database commit, the argument points to a nul-terminated
+** string containing the transactions super-journal file name. VFSes that
+** do not need this signal should silently ignore this opcode. Applications
+** should not call [sqlite3_file_control()] with this opcode as doing so may
+** disrupt the operation of the specialized VFSes that do require it.
+**
+** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
+** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
+** and sent to the VFS after a transaction has been committed immediately
+** but before the database is unlocked. VFSes that do not need this signal
+** should silently ignore this opcode. Applications should not call
+** [sqlite3_file_control()] with this opcode as doing so may disrupt the
+** operation of the specialized VFSes that do require it.
+**
+** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
+** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
+** retry counts and intervals for certain disk I/O operations for the
+** windows [VFS] in order to provide robustness in the presence of
+** anti-virus programs.  By default, the windows VFS will retry file read,
+** file write, and file delete operations up to 10 times, with a delay
+** of 25 milliseconds before the first retry and with the delay increasing
+** by an additional 25 milliseconds with each subsequent retry.  This
+** opcode allows these two values (10 retries and 25 milliseconds of delay)
+** to be adjusted.  The values are changed for all database connections
+** within the same process.  The argument is a pointer to an array of two
+** integers where the first integer is the new retry count and the second
+** integer is the delay.  If either integer is negative, then the setting
+** is not changed but instead the prior value of that setting is written
+** into the array entry, allowing the current retry settings to be
+** interrogated.  The zDbName parameter is ignored.
+**
+** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
+** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
+** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
+** write ahead log ([WAL file]) and shared memory
+** files used for transaction control
+** are automatically deleted when the latest connection to the database
+** closes.  Setting persistent WAL mode causes those files to persist after
+** close.  Persisting the files is useful when other processes that do not
+** have write permission on the directory containing the database file want
+** to read the database file, as the WAL and shared memory files must exist
+** in order for the database to be readable.  The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
+** WAL mode.  If the integer is -1, then it is overwritten with the current
+** WAL persistence setting.
+**
+** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
+** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
+** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
+** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
+** xDeviceCharacteristics methods. The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
+** mode.  If the integer is -1, then it is overwritten with the current
+** zero-damage mode setting.
+**
+** <li>[[SQLITE_FCNTL_OVERWRITE]]
+** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
+** a write transaction to indicate that, unless it is rolled back for some
+** reason, the entire database file will be overwritten by the current
+** transaction. This is used by VACUUM operations.
+**
+** <li>[[SQLITE_FCNTL_VFSNAME]]
+** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
+** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
+** final bottom-level VFS are written into memory obtained from
+** [sqlite3_malloc()] and the result is stored in the char* variable
+** that the fourth parameter of [sqlite3_file_control()] points to.
+** The caller is responsible for freeing the memory when done.  As with
+** all file-control actions, there is no guarantee that this will actually
+** do anything.  Callers should initialize the char* variable to a NULL
+** pointer in case this file-control is not implemented.  This file-control
+** is intended for diagnostic use only.
+**
+** <li>[[SQLITE_FCNTL_VFS_POINTER]]
+** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
+** [VFSes] currently in use.  ^(The argument X in
+** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
+** of type "[sqlite3_vfs] **".  This opcodes will set *X
+** to a pointer to the top-level VFS.)^
+** ^When there are multiple VFS shims in the stack, this opcode finds the
+** upper-most shim only.
+**
+** <li>[[SQLITE_FCNTL_PRAGMA]]
+** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
+** file control is sent to the open [sqlite3_file] object corresponding
+** to the database file to which the pragma statement refers. ^The argument
+** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
+** pointers to strings (char**) in which the second element of the array
+** is the name of the pragma and the third element is the argument to the
+** pragma or NULL if the pragma has no argument.  ^The handler for an
+** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
+** of the char** argument point to a string obtained from [sqlite3_mprintf()]
+** or the equivalent and that string will become the result of the pragma or
+** the error message if the pragma fails. ^If the
+** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
+** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
+** file control returns [SQLITE_OK], then the parser assumes that the
+** VFS has handled the PRAGMA itself and the parser generates a no-op
+** prepared statement if result string is NULL, or that returns a copy
+** of the result string if the string is non-NULL.
+** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
+** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
+** that the VFS encountered an error while handling the [PRAGMA] and the
+** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
+** file control occurs at the beginning of pragma statement analysis and so
+** it is able to override built-in [PRAGMA] statements.
+**
+** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
+** ^The [SQLITE_FCNTL_BUSYHANDLER]
+** file-control may be invoked by SQLite on the database file handle
+** shortly after it is opened in order to provide a custom VFS with access
+** to the connection's busy-handler callback. The argument is of type (void**)
+** - an array of two (void *) values. The first (void *) actually points
+** to a function of type (int (*)(void *)). In order to invoke the connection's
+** busy-handler, this function should be invoked with the second (void *) in
+** the array as the only argument. If it returns non-zero, then the operation
+** should be retried. If it returns zero, the custom VFS should abandon the
+** current operation.
+**
+** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
+** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
+** to have SQLite generate a
+** temporary filename using the same algorithm that is followed to generate
+** temporary filenames for TEMP tables and other internal uses.  The
+** argument should be a char** which will be filled with the filename
+** written into memory obtained from [sqlite3_malloc()].  The caller should
+** invoke [sqlite3_free()] on the result to avoid a memory leak.
+**
+** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
+** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
+** maximum number of bytes that will be used for memory-mapped I/O.
+** The argument is a pointer to a value of type sqlite3_int64 that
+** is an advisory maximum number of bytes in the file to memory map.  The
+** pointer is overwritten with the old value.  The limit is not changed if
+** the value originally pointed to is negative, and so the current limit
+** can be queried by passing in a pointer to a negative number.  This
+** file-control is used internally to implement [PRAGMA mmap_size].
+**
+** <li>[[SQLITE_FCNTL_TRACE]]
+** The [SQLITE_FCNTL_TRACE] file control provides advisory information
+** to the VFS about what the higher layers of the SQLite stack are doing.
+** This file control is used by some VFS activity tracing [shims].
+** The argument is a zero-terminated string.  Higher layers in the
+** SQLite stack may generate instances of this file control if
+** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
+**
+** <li>[[SQLITE_FCNTL_HAS_MOVED]]
+** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
+** pointer to an integer and it writes a boolean into that integer depending
+** on whether or not the file has been renamed, moved, or deleted since it
+** was first opened.
+**
+** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
+** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
+** underlying native file handle associated with a file handle.  This file
+** control interprets its argument as a pointer to a native file handle and
+** writes the resulting value there.
+**
+** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
+** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
+** opcode causes the xFileControl method to swap the file handle with the one
+** pointed to by the pArg argument.  This capability is used during testing
+** and only needs to be supported when SQLITE_TEST is defined.
+**
+** <li>[[SQLITE_FCNTL_NULL_IO]]
+** The [SQLITE_FCNTL_NULL_IO] opcode sets the low-level file descriptor
+** or file handle for the [sqlite3_file] object such that it will no longer
+** read or write to the database file.
+**
+** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
+** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
+** be advantageous to block on the next WAL lock if the lock is not immediately
+** available.  The WAL subsystem issues this signal during rare
+** circumstances in order to fix a problem with priority inversion.
+** Applications should <em>not</em> use this file-control.
+**
+** <li>[[SQLITE_FCNTL_ZIPVFS]]
+** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
+** VFS should return SQLITE_NOTFOUND for this opcode.
+**
+** <li>[[SQLITE_FCNTL_RBU]]
+** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
+** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
+** this opcode.
+**
+** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
+** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
+** the file descriptor is placed in "batch write mode", which
+** means all subsequent write operations will be deferred and done
+** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
+** that do not support batch atomic writes will return SQLITE_NOTFOUND.
+** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
+** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
+** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
+** no VFS interface calls on the same [sqlite3_file] file descriptor
+** except for calls to the xWrite method and the xFileControl method
+** with [SQLITE_FCNTL_SIZE_HINT].
+**
+** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
+** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
+** operations since the previous successful call to
+** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
+** This file control returns [SQLITE_OK] if and only if the writes were
+** all performed successfully and have been committed to persistent storage.
+** ^Regardless of whether or not it is successful, this file control takes
+** the file descriptor out of batch write mode so that all subsequent
+** write operations are independent.
+** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
+** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
+**
+** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
+** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
+** operations since the previous successful call to
+** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
+** ^This file control takes the file descriptor out of batch write mode
+** so that all subsequent write operations are independent.
+** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
+** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
+**
+** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
+** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
+** to block for up to M milliseconds before failing when attempting to
+** obtain a file lock using the xLock or xShmLock methods of the VFS.
+** The parameter is a pointer to a 32-bit signed integer that contains
+** the value that M is to be set to. Before returning, the 32-bit signed
+** integer is overwritten with the previous value of M.
+**
+** <li>[[SQLITE_FCNTL_DATA_VERSION]]
+** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
+** a database file.  The argument is a pointer to a 32-bit unsigned integer.
+** The "data version" for the pager is written into the pointer.  The
+** "data version" changes whenever any change occurs to the corresponding
+** database file, either through SQL statements on the same database
+** connection or through transactions committed by separate database
+** connections possibly in other processes. The [sqlite3_total_changes()]
+** interface can be used to find if any database on the connection has changed,
+** but that interface responds to changes on TEMP as well as MAIN and does
+** not provide a mechanism to detect changes to MAIN only.  Also, the
+** [sqlite3_total_changes()] interface responds to internal changes only and
+** omits changes made by other database connections.  The
+** [PRAGMA data_version] command provides a mechanism to detect changes to
+** a single attached database that occur due to other database connections,
+** but omits changes implemented by the database connection on which it is
+** called.  This file control is the only mechanism to detect changes that
+** happen either internally or externally and that are associated with
+** a particular attached database.
+**
+** <li>[[SQLITE_FCNTL_CKPT_START]]
+** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
+** in wal mode before the client starts to copy pages from the wal
+** file to the database file.
+**
+** <li>[[SQLITE_FCNTL_CKPT_DONE]]
+** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
+** in wal mode after the client has finished copying pages from the wal
+** file to the database file, but before the *-shm file is updated to
+** record the fact that the pages have been checkpointed.
+**
+** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
+** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
+** whether or not there is a database client in another process with a wal-mode
+** transaction open on the database or not. It is only available on unix.The
+** (void*) argument passed with this file-control should be a pointer to a
+** value of type (int). The integer value is set to 1 if the database is a wal
+** mode database and there exists at least one client in another process that
+** currently has an SQL transaction open on the database. It is set to 0 if
+** the database is not a wal-mode db, or if there is no such connection in any
+** other process. This opcode cannot be used to detect transactions opened
+** by clients within the current process, only within other processes.
+**
+** <li>[[SQLITE_FCNTL_CKSM_FILE]]
+** The [SQLITE_FCNTL_CKSM_FILE] opcode is for use internally by the
+** [checksum VFS shim] only.
+**
+** <li>[[SQLITE_FCNTL_RESET_CACHE]]
+** If there is currently no transaction open on the database, and the
+** database is not a temp db, then the [SQLITE_FCNTL_RESET_CACHE] file-control
+** purges the contents of the in-memory page cache. If there is an open
+** transaction, or if the db is a temp-db, this opcode is a no-op, not an error.
+** </ul>
+*/
+#define SQLITE_FCNTL_LOCKSTATE               1
+#define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
+#define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
+#define SQLITE_FCNTL_LAST_ERRNO              4
+#define SQLITE_FCNTL_SIZE_HINT               5
+#define SQLITE_FCNTL_CHUNK_SIZE              6
+#define SQLITE_FCNTL_FILE_POINTER            7
+#define SQLITE_FCNTL_SYNC_OMITTED            8
+#define SQLITE_FCNTL_WIN32_AV_RETRY          9
+#define SQLITE_FCNTL_PERSIST_WAL            10
+#define SQLITE_FCNTL_OVERWRITE              11
+#define SQLITE_FCNTL_VFSNAME                12
+#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
+#define SQLITE_FCNTL_PRAGMA                 14
+#define SQLITE_FCNTL_BUSYHANDLER            15
+#define SQLITE_FCNTL_TEMPFILENAME           16
+#define SQLITE_FCNTL_MMAP_SIZE              18
+#define SQLITE_FCNTL_TRACE                  19
+#define SQLITE_FCNTL_HAS_MOVED              20
+#define SQLITE_FCNTL_SYNC                   21
+#define SQLITE_FCNTL_COMMIT_PHASETWO        22
+#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
+#define SQLITE_FCNTL_WAL_BLOCK              24
+#define SQLITE_FCNTL_ZIPVFS                 25
+#define SQLITE_FCNTL_RBU                    26
+#define SQLITE_FCNTL_VFS_POINTER            27
+#define SQLITE_FCNTL_JOURNAL_POINTER        28
+#define SQLITE_FCNTL_WIN32_GET_HANDLE       29
+#define SQLITE_FCNTL_PDB                    30
+#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
+#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
+#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
+#define SQLITE_FCNTL_LOCK_TIMEOUT           34
+#define SQLITE_FCNTL_DATA_VERSION           35
+#define SQLITE_FCNTL_SIZE_LIMIT             36
+#define SQLITE_FCNTL_CKPT_DONE              37
+#define SQLITE_FCNTL_RESERVE_BYTES          38
+#define SQLITE_FCNTL_CKPT_START             39
+#define SQLITE_FCNTL_EXTERNAL_READER        40
+#define SQLITE_FCNTL_CKSM_FILE              41
+#define SQLITE_FCNTL_RESET_CACHE            42
+#define SQLITE_FCNTL_NULL_IO                43
+
+/* deprecated names */
+#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
+#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
+#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
+
+
+/*
+** CAPI3REF: Mutex Handle
+**
+** The mutex module within SQLite defines [sqlite3_mutex] to be an
+** abstract type for a mutex object.  The SQLite core never looks
+** at the internal representation of an [sqlite3_mutex].  It only
+** deals with pointers to the [sqlite3_mutex] object.
+**
+** Mutexes are created using [sqlite3_mutex_alloc()].
+*/
+typedef struct sqlite3_mutex sqlite3_mutex;
+
+/*
+** CAPI3REF: Loadable Extension Thunk
+**
+** A pointer to the opaque sqlite3_api_routines structure is passed as
+** the third parameter to entry points of [loadable extensions].  This
+** structure must be typedefed in order to work around compiler warnings
+** on some platforms.
+*/
+typedef struct sqlite3_api_routines sqlite3_api_routines;
+
+/*
+** CAPI3REF: File Name
+**
+** Type [sqlite3_filename] is used by SQLite to pass filenames to the
+** xOpen method of a [VFS]. It may be cast to (const char*) and treated
+** as a normal, nul-terminated, UTF-8 buffer containing the filename, but
+** may also be passed to special APIs such as:
+**
+** <ul>
+** <li>  sqlite3_filename_database()
+** <li>  sqlite3_filename_journal()
+** <li>  sqlite3_filename_wal()
+** <li>  sqlite3_uri_parameter()
+** <li>  sqlite3_uri_boolean()
+** <li>  sqlite3_uri_int64()
+** <li>  sqlite3_uri_key()
+** </ul>
+*/
+typedef const char *sqlite3_filename;
+
+/*
+** CAPI3REF: OS Interface Object
+**
+** An instance of the sqlite3_vfs object defines the interface between
+** the SQLite core and the underlying operating system.  The "vfs"
+** in the name of the object stands for "virtual file system".  See
+** the [VFS | VFS documentation] for further information.
+**
+** The VFS interface is sometimes extended by adding new methods onto
+** the end.  Each time such an extension occurs, the iVersion field
+** is incremented.  The iVersion value started out as 1 in
+** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
+** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
+** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
+** may be appended to the sqlite3_vfs object and the iVersion value
+** may increase again in future versions of SQLite.
+** Note that due to an oversight, the structure
+** of the sqlite3_vfs object changed in the transition from
+** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
+** and yet the iVersion field was not increased.
+**
+** The szOsFile field is the size of the subclassed [sqlite3_file]
+** structure used by this VFS.  mxPathname is the maximum length of
+** a pathname in this VFS.
+**
+** Registered sqlite3_vfs objects are kept on a linked list formed by
+** the pNext pointer.  The [sqlite3_vfs_register()]
+** and [sqlite3_vfs_unregister()] interfaces manage this list
+** in a thread-safe way.  The [sqlite3_vfs_find()] interface
+** searches the list.  Neither the application code nor the VFS
+** implementation should use the pNext pointer.
+**
+** The pNext field is the only field in the sqlite3_vfs
+** structure that SQLite will ever modify.  SQLite will only access
+** or modify this field while holding a particular static mutex.
+** The application should never modify anything within the sqlite3_vfs
+** object once the object has been registered.
+**
+** The zName field holds the name of the VFS module.  The name must
+** be unique across all VFS modules.
+**
+** [[sqlite3_vfs.xOpen]]
+** ^SQLite guarantees that the zFilename parameter to xOpen
+** is either a NULL pointer or string obtained
+** from xFullPathname() with an optional suffix added.
+** ^If a suffix is added to the zFilename parameter, it will
+** consist of a single "-" character followed by no more than
+** 11 alphanumeric and/or "-" characters.
+** ^SQLite further guarantees that
+** the string will be valid and unchanged until xClose() is
+** called. Because of the previous sentence,
+** the [sqlite3_file] can safely store a pointer to the
+** filename if it needs to remember the filename for some reason.
+** If the zFilename parameter to xOpen is a NULL pointer then xOpen
+** must invent its own temporary name for the file.  ^Whenever the
+** xFilename parameter is NULL it will also be the case that the
+** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
+**
+** The flags argument to xOpen() includes all bits set in
+** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
+** or [sqlite3_open16()] is used, then flags includes at least
+** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
+** If xOpen() opens a file read-only then it sets *pOutFlags to
+** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
+**
+** ^(SQLite will also add one of the following flags to the xOpen()
+** call, depending on the object being opened:
+**
+** <ul>
+** <li>  [SQLITE_OPEN_MAIN_DB]
+** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
+** <li>  [SQLITE_OPEN_TEMP_DB]
+** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
+** <li>  [SQLITE_OPEN_TRANSIENT_DB]
+** <li>  [SQLITE_OPEN_SUBJOURNAL]
+** <li>  [SQLITE_OPEN_SUPER_JOURNAL]
+** <li>  [SQLITE_OPEN_WAL]
+** </ul>)^
+**
+** The file I/O implementation can use the object type flags to
+** change the way it deals with files.  For example, an application
+** that does not care about crash recovery or rollback might make
+** the open of a journal file a no-op.  Writes to this journal would
+** also be no-ops, and any attempt to read the journal would return
+** SQLITE_IOERR.  Or the implementation might recognize that a database
+** file will be doing page-aligned sector reads and writes in a random
+** order and set up its I/O subsystem accordingly.
+**
+** SQLite might also add one of the following flags to the xOpen method:
+**
+** <ul>
+** <li> [SQLITE_OPEN_DELETEONCLOSE]
+** <li> [SQLITE_OPEN_EXCLUSIVE]
+** </ul>
+**
+** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
+** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
+** will be set for TEMP databases and their journals, transient
+** databases, and subjournals.
+**
+** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
+** with the [SQLITE_OPEN_CREATE] flag, which are both directly
+** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
+** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
+** SQLITE_OPEN_CREATE, is used to indicate that file should always
+** be created, and that it is an error if it already exists.
+** It is <i>not</i> used to indicate the file should be opened
+** for exclusive access.
+**
+** ^At least szOsFile bytes of memory are allocated by SQLite
+** to hold the [sqlite3_file] structure passed as the third
+** argument to xOpen.  The xOpen method does not have to
+** allocate the structure; it should just fill it in.  Note that
+** the xOpen method must set the sqlite3_file.pMethods to either
+** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
+** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
+** element will be valid after xOpen returns regardless of the success
+** or failure of the xOpen call.
+**
+** [[sqlite3_vfs.xAccess]]
+** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
+** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
+** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
+** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
+** flag is never actually used and is not implemented in the built-in
+** VFSes of SQLite.  The file is named by the second argument and can be a
+** directory. The xAccess method returns [SQLITE_OK] on success or some
+** non-zero error code if there is an I/O error or if the name of
+** the file given in the second argument is illegal.  If SQLITE_OK
+** is returned, then non-zero or zero is written into *pResOut to indicate
+** whether or not the file is accessible.
+**
+** ^SQLite will always allocate at least mxPathname+1 bytes for the
+** output buffer xFullPathname.  The exact size of the output buffer
+** is also passed as a parameter to both  methods. If the output buffer
+** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
+** handled as a fatal error by SQLite, vfs implementations should endeavor
+** to prevent this by setting mxPathname to a sufficiently large value.
+**
+** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
+** interfaces are not strictly a part of the filesystem, but they are
+** included in the VFS structure for completeness.
+** The xRandomness() function attempts to return nBytes bytes
+** of good-quality randomness into zOut.  The return value is
+** the actual number of bytes of randomness obtained.
+** The xSleep() method causes the calling thread to sleep for at
+** least the number of microseconds given.  ^The xCurrentTime()
+** method returns a Julian Day Number for the current date and time as
+** a floating point value.
+** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
+** Day Number multiplied by 86400000 (the number of milliseconds in
+** a 24-hour day).
+** ^SQLite will use the xCurrentTimeInt64() method to get the current
+** date and time if that method is available (if iVersion is 2 or
+** greater and the function pointer is not NULL) and will fall back
+** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
+**
+** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
+** are not used by the SQLite core.  These optional interfaces are provided
+** by some VFSes to facilitate testing of the VFS code. By overriding
+** system calls with functions under its control, a test program can
+** simulate faults and error conditions that would otherwise be difficult
+** or impossible to induce.  The set of system calls that can be overridden
+** varies from one VFS to another, and from one version of the same VFS to the
+** next.  Applications that use these interfaces must be prepared for any
+** or all of these interfaces to be NULL or for their behavior to change
+** from one release to the next.  Applications must not attempt to access
+** any of these methods if the iVersion of the VFS is less than 3.
+*/
+typedef struct sqlite3_vfs sqlite3_vfs;
+typedef void (*sqlite3_syscall_ptr)(void);
+struct sqlite3_vfs {
+  int iVersion;            /* Structure version number (currently 3) */
+  int szOsFile;            /* Size of subclassed sqlite3_file */
+  int mxPathname;          /* Maximum file pathname length */
+  sqlite3_vfs *pNext;      /* Next registered VFS */
+  const char *zName;       /* Name of this virtual file system */
+  void *pAppData;          /* Pointer to application-specific data */
+  int (*xOpen)(sqlite3_vfs*, sqlite3_filename zName, sqlite3_file*,
+               int flags, int *pOutFlags);
+  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
+  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
+  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
+  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
+  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
+  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
+  void (*xDlClose)(sqlite3_vfs*, void*);
+  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
+  int (*xSleep)(sqlite3_vfs*, int microseconds);
+  int (*xCurrentTime)(sqlite3_vfs*, double*);
+  int (*xGetLastError)(sqlite3_vfs*, int, char *);
+  /*
+  ** The methods above are in version 1 of the sqlite_vfs object
+  ** definition.  Those that follow are added in version 2 or later
+  */
+  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
+  /*
+  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
+  ** Those below are for version 3 and greater.
+  */
+  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
+  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
+  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
+  /*
+  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
+  ** New fields may be appended in future versions.  The iVersion
+  ** value will increment whenever this happens.
+  */
+};
+
+/*
+** CAPI3REF: Flags for the xAccess VFS method
+**
+** These integer constants can be used as the third parameter to
+** the xAccess method of an [sqlite3_vfs] object.  They determine
+** what kind of permissions the xAccess method is looking for.
+** With SQLITE_ACCESS_EXISTS, the xAccess method
+** simply checks whether the file exists.
+** With SQLITE_ACCESS_READWRITE, the xAccess method
+** checks whether the named directory is both readable and writable
+** (in other words, if files can be added, removed, and renamed within
+** the directory).
+** The SQLITE_ACCESS_READWRITE constant is currently used only by the
+** [temp_store_directory pragma], though this could change in a future
+** release of SQLite.
+** With SQLITE_ACCESS_READ, the xAccess method
+** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
+** currently unused, though it might be used in a future release of
+** SQLite.
+*/
+#define SQLITE_ACCESS_EXISTS    0
+#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
+#define SQLITE_ACCESS_READ      2   /* Unused */
+
+/*
+** CAPI3REF: Flags for the xShmLock VFS method
+**
+** These integer constants define the various locking operations
+** allowed by the xShmLock method of [sqlite3_io_methods].  The
+** following are the only legal combinations of flags to the
+** xShmLock method:
+**
+** <ul>
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
+** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
+** </ul>
+**
+** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
+** was given on the corresponding lock.
+**
+** The xShmLock method can transition between unlocked and SHARED or
+** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
+** and EXCLUSIVE.
+*/
+#define SQLITE_SHM_UNLOCK       1
+#define SQLITE_SHM_LOCK         2
+#define SQLITE_SHM_SHARED       4
+#define SQLITE_SHM_EXCLUSIVE    8
+
+/*
+** CAPI3REF: Maximum xShmLock index
+**
+** The xShmLock method on [sqlite3_io_methods] may use values
+** between 0 and this upper bound as its "offset" argument.
+** The SQLite core will never attempt to acquire or release a
+** lock outside of this range
+*/
+#define SQLITE_SHM_NLOCK        8
+
+
+/*
+** CAPI3REF: Initialize The SQLite Library
+**
+** ^The sqlite3_initialize() routine initializes the
+** SQLite library.  ^The sqlite3_shutdown() routine
+** deallocates any resources that were allocated by sqlite3_initialize().
+** These routines are designed to aid in process initialization and
+** shutdown on embedded systems.  Workstation applications using
+** SQLite normally do not need to invoke either of these routines.
+**
+** A call to sqlite3_initialize() is an "effective" call if it is
+** the first time sqlite3_initialize() is invoked during the lifetime of
+** the process, or if it is the first time sqlite3_initialize() is invoked
+** following a call to sqlite3_shutdown().  ^(Only an effective call
+** of sqlite3_initialize() does any initialization.  All other calls
+** are harmless no-ops.)^
+**
+** A call to sqlite3_shutdown() is an "effective" call if it is the first
+** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
+** an effective call to sqlite3_shutdown() does any deinitialization.
+** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
+**
+** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
+** is not.  The sqlite3_shutdown() interface must only be called from a
+** single thread.  All open [database connections] must be closed and all
+** other SQLite resources must be deallocated prior to invoking
+** sqlite3_shutdown().
+**
+** Among other things, ^sqlite3_initialize() will invoke
+** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
+** will invoke sqlite3_os_end().
+**
+** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
+** ^If for some reason, sqlite3_initialize() is unable to initialize
+** the library (perhaps it is unable to allocate a needed resource such
+** as a mutex) it returns an [error code] other than [SQLITE_OK].
+**
+** ^The sqlite3_initialize() routine is called internally by many other
+** SQLite interfaces so that an application usually does not need to
+** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
+** calls sqlite3_initialize() so the SQLite library will be automatically
+** initialized when [sqlite3_open()] is called if it has not be initialized
+** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
+** compile-time option, then the automatic calls to sqlite3_initialize()
+** are omitted and the application must call sqlite3_initialize() directly
+** prior to using any other SQLite interface.  For maximum portability,
+** it is recommended that applications always invoke sqlite3_initialize()
+** directly prior to using any other SQLite interface.  Future releases
+** of SQLite may require this.  In other words, the behavior exhibited
+** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
+** default behavior in some future release of SQLite.
+**
+** The sqlite3_os_init() routine does operating-system specific
+** initialization of the SQLite library.  The sqlite3_os_end()
+** routine undoes the effect of sqlite3_os_init().  Typical tasks
+** performed by these routines include allocation or deallocation
+** of static resources, initialization of global variables,
+** setting up a default [sqlite3_vfs] module, or setting up
+** a default configuration using [sqlite3_config()].
+**
+** The application should never invoke either sqlite3_os_init()
+** or sqlite3_os_end() directly.  The application should only invoke
+** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
+** interface is called automatically by sqlite3_initialize() and
+** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
+** implementations for sqlite3_os_init() and sqlite3_os_end()
+** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
+** When [custom builds | built for other platforms]
+** (using the [SQLITE_OS_OTHER=1] compile-time
+** option) the application must supply a suitable implementation for
+** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
+** implementation of sqlite3_os_init() or sqlite3_os_end()
+** must return [SQLITE_OK] on success and some other [error code] upon
+** failure.
+*/
+SQLITE_API int sqlite3_initialize(void);
+SQLITE_API int sqlite3_shutdown(void);
+SQLITE_API int sqlite3_os_init(void);
+SQLITE_API int sqlite3_os_end(void);
+
+/*
+** CAPI3REF: Configuring The SQLite Library
+**
+** The sqlite3_config() interface is used to make global configuration
+** changes to SQLite in order to tune SQLite to the specific needs of
+** the application.  The default configuration is recommended for most
+** applications and so this routine is usually not necessary.  It is
+** provided to support rare applications with unusual needs.
+**
+** <b>The sqlite3_config() interface is not threadsafe. The application
+** must ensure that no other SQLite interfaces are invoked by other
+** threads while sqlite3_config() is running.</b>
+**
+** The first argument to sqlite3_config() is an integer
+** [configuration option] that determines
+** what property of SQLite is to be configured.  Subsequent arguments
+** vary depending on the [configuration option]
+** in the first argument.
+**
+** For most configuration options, the sqlite3_config() interface
+** may only be invoked prior to library initialization using
+** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
+** The exceptional configuration options that may be invoked at any time
+** are called "anytime configuration options".
+** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
+** [sqlite3_shutdown()] with a first argument that is not an anytime
+** configuration option, then the sqlite3_config() call will return SQLITE_MISUSE.
+** Note, however, that ^sqlite3_config() can be called as part of the
+** implementation of an application-defined [sqlite3_os_init()].
+**
+** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
+** ^If the option is unknown or SQLite is unable to set the option
+** then this routine returns a non-zero [error code].
+*/
+SQLITE_API int sqlite3_config(int, ...);
+
+/*
+** CAPI3REF: Configure database connections
+** METHOD: sqlite3
+**
+** The sqlite3_db_config() interface is used to make configuration
+** changes to a [database connection].  The interface is similar to
+** [sqlite3_config()] except that the changes apply to a single
+** [database connection] (specified in the first argument).
+**
+** The second argument to sqlite3_db_config(D,V,...)  is the
+** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
+** that indicates what aspect of the [database connection] is being configured.
+** Subsequent arguments vary depending on the configuration verb.
+**
+** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
+** the call is considered successful.
+*/
+SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Memory Allocation Routines
+**
+** An instance of this object defines the interface between SQLite
+** and low-level memory allocation routines.
+**
+** This object is used in only one place in the SQLite interface.
+** A pointer to an instance of this object is the argument to
+** [sqlite3_config()] when the configuration option is
+** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
+** By creating an instance of this object
+** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
+** during configuration, an application can specify an alternative
+** memory allocation subsystem for SQLite to use for all of its
+** dynamic memory needs.
+**
+** Note that SQLite comes with several [built-in memory allocators]
+** that are perfectly adequate for the overwhelming majority of applications
+** and that this object is only useful to a tiny minority of applications
+** with specialized memory allocation requirements.  This object is
+** also used during testing of SQLite in order to specify an alternative
+** memory allocator that simulates memory out-of-memory conditions in
+** order to verify that SQLite recovers gracefully from such
+** conditions.
+**
+** The xMalloc, xRealloc, and xFree methods must work like the
+** malloc(), realloc() and free() functions from the standard C library.
+** ^SQLite guarantees that the second argument to
+** xRealloc is always a value returned by a prior call to xRoundup.
+**
+** xSize should return the allocated size of a memory allocation
+** previously obtained from xMalloc or xRealloc.  The allocated size
+** is always at least as big as the requested size but may be larger.
+**
+** The xRoundup method returns what would be the allocated size of
+** a memory allocation given a particular requested size.  Most memory
+** allocators round up memory allocations at least to the next multiple
+** of 8.  Some allocators round up to a larger multiple or to a power of 2.
+** Every memory allocation request coming in through [sqlite3_malloc()]
+** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
+** that causes the corresponding memory allocation to fail.
+**
+** The xInit method initializes the memory allocator.  For example,
+** it might allocate any required mutexes or initialize internal data
+** structures.  The xShutdown method is invoked (indirectly) by
+** [sqlite3_shutdown()] and should deallocate any resources acquired
+** by xInit.  The pAppData pointer is used as the only parameter to
+** xInit and xShutdown.
+**
+** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
+** the xInit method, so the xInit method need not be threadsafe.  The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  For all other methods, SQLite
+** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
+** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
+** it is by default) and so the methods are automatically serialized.
+** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
+** methods must be threadsafe or else make their own arrangements for
+** serialization.
+**
+** SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+*/
+typedef struct sqlite3_mem_methods sqlite3_mem_methods;
+struct sqlite3_mem_methods {
+  void *(*xMalloc)(int);         /* Memory allocation function */
+  void (*xFree)(void*);          /* Free a prior allocation */
+  void *(*xRealloc)(void*,int);  /* Resize an allocation */
+  int (*xSize)(void*);           /* Return the size of an allocation */
+  int (*xRoundup)(int);          /* Round up request size to allocation size */
+  int (*xInit)(void*);           /* Initialize the memory allocator */
+  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
+  void *pAppData;                /* Argument to xInit() and xShutdown() */
+};
+
+/*
+** CAPI3REF: Configuration Options
+** KEYWORDS: {configuration option}
+**
+** These constants are the available integer configuration options that
+** can be passed as the first argument to the [sqlite3_config()] interface.
+**
+** Most of the configuration options for sqlite3_config()
+** will only work if invoked prior to [sqlite3_initialize()] or after
+** [sqlite3_shutdown()].  The few exceptions to this rule are called
+** "anytime configuration options".
+** ^Calling [sqlite3_config()] with a first argument that is not an
+** anytime configuration option in between calls to [sqlite3_initialize()] and
+** [sqlite3_shutdown()] is a no-op that returns SQLITE_MISUSE.
+**
+** The set of anytime configuration options can change (by insertions
+** and/or deletions) from one release of SQLite to the next.
+** As of SQLite version 3.42.0, the complete set of anytime configuration
+** options is:
+** <ul>
+** <li> SQLITE_CONFIG_LOG
+** <li> SQLITE_CONFIG_PCACHE_HDRSZ
+** </ul>
+**
+** New configuration options may be added in future releases of SQLite.
+** Existing configuration options might be discontinued.  Applications
+** should check the return code from [sqlite3_config()] to make sure that
+** the call worked.  The [sqlite3_config()] interface will return a
+** non-zero [error code] if a discontinued or unsupported configuration option
+** is invoked.
+**
+** <dl>
+** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Single-thread.  In other words, it disables
+** all mutexing and puts SQLite into a mode where it can only be used
+** by a single thread.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to change the [threading mode] from its default
+** value of Single-thread and so [sqlite3_config()] will return
+** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
+** configuration option.</dd>
+**
+** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Multi-thread.  In other words, it disables
+** mutexing on [database connection] and [prepared statement] objects.
+** The application is responsible for serializing access to
+** [database connections] and [prepared statements].  But other mutexes
+** are enabled so that SQLite will be safe to use in a multi-threaded
+** environment as long as no two threads attempt to use the same
+** [database connection] at the same time.  ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Multi-thread [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
+**
+** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
+** <dd>There are no arguments to this option.  ^This option sets the
+** [threading mode] to Serialized. In other words, this option enables
+** all mutexes including the recursive
+** mutexes on [database connection] and [prepared statement] objects.
+** In this mode (which is the default when SQLite is compiled with
+** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
+** to [database connections] and [prepared statements] so that the
+** application is free to use the same [database connection] or the
+** same [prepared statement] in different threads at the same time.
+** ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** it is not possible to set the Serialized [threading mode] and
+** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
+** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
+**
+** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
+** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
+** a pointer to an instance of the [sqlite3_mem_methods] structure.
+** The argument specifies
+** alternative low-level memory allocation routines to be used in place of
+** the memory allocation routines built into SQLite.)^ ^SQLite makes
+** its own private copy of the content of the [sqlite3_mem_methods] structure
+** before the [sqlite3_config()] call returns.</dd>
+**
+** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
+** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
+** is a pointer to an instance of the [sqlite3_mem_methods] structure.
+** The [sqlite3_mem_methods]
+** structure is filled with the currently defined memory allocation routines.)^
+** This option can be used to overload the default memory allocation
+** routines with a wrapper that simulations memory allocation failure or
+** tracks memory usage, for example. </dd>
+**
+** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
+** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
+** type int, interpreted as a boolean, which if true provides a hint to
+** SQLite that it should avoid large memory allocations if possible.
+** SQLite will run faster if it is free to make large memory allocations,
+** but some application might prefer to run slower in exchange for
+** guarantees about memory fragmentation that are possible if large
+** allocations are avoided.  This hint is normally off.
+** </dd>
+**
+** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
+** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
+** interpreted as a boolean, which enables or disables the collection of
+** memory allocation statistics. ^(When memory allocation statistics are
+** disabled, the following SQLite interfaces become non-operational:
+**   <ul>
+**   <li> [sqlite3_hard_heap_limit64()]
+**   <li> [sqlite3_memory_used()]
+**   <li> [sqlite3_memory_highwater()]
+**   <li> [sqlite3_soft_heap_limit64()]
+**   <li> [sqlite3_status64()]
+**   </ul>)^
+** ^Memory allocation statistics are enabled by default unless SQLite is
+** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
+** allocation statistics are disabled by default.
+** </dd>
+**
+** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
+** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
+** </dd>
+**
+** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
+** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
+** that SQLite can use for the database page cache with the default page
+** cache implementation.
+** This configuration option is a no-op if an application-defined page
+** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
+** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
+** 8-byte aligned memory (pMem), the size of each page cache line (sz),
+** and the number of cache lines (N).
+** The sz argument should be the size of the largest database page
+** (a power of two between 512 and 65536) plus some extra bytes for each
+** page header.  ^The number of extra bytes needed by the page header
+** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
+** ^It is harmless, apart from the wasted memory,
+** for the sz parameter to be larger than necessary.  The pMem
+** argument must be either a NULL pointer or a pointer to an 8-byte
+** aligned block of memory of at least sz*N bytes, otherwise
+** subsequent behavior is undefined.
+** ^When pMem is not NULL, SQLite will strive to use the memory provided
+** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
+** a page cache line is larger than sz bytes or if all of the pMem buffer
+** is exhausted.
+** ^If pMem is NULL and N is non-zero, then each database connection
+** does an initial bulk allocation for page cache memory
+** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
+** of -1024*N bytes if N is negative, . ^If additional
+** page cache memory is needed beyond what is provided by the initial
+** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
+** additional cache line. </dd>
+**
+** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
+** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
+** that SQLite will use for all of its dynamic memory allocation needs
+** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
+** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
+** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
+** [SQLITE_ERROR] if invoked otherwise.
+** ^There are three arguments to SQLITE_CONFIG_HEAP:
+** An 8-byte aligned pointer to the memory,
+** the number of bytes in the memory buffer, and the minimum allocation size.
+** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
+** to using its default memory allocator (the system malloc() implementation),
+** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
+** memory pointer is not NULL then the alternative memory
+** allocator is engaged to handle all of SQLites memory allocation needs.
+** The first pointer (the memory pointer) must be aligned to an 8-byte
+** boundary or subsequent behavior of SQLite will be undefined.
+** The minimum allocation size is capped at 2**12. Reasonable values
+** for the minimum allocation size are 2**5 through 2**8.</dd>
+**
+** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
+** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
+** pointer to an instance of the [sqlite3_mutex_methods] structure.
+** The argument specifies alternative low-level mutex routines to be used
+** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
+** the content of the [sqlite3_mutex_methods] structure before the call to
+** [sqlite3_config()] returns. ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
+**
+** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
+** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
+** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
+** [sqlite3_mutex_methods]
+** structure is filled with the currently defined mutex routines.)^
+** This option can be used to overload the default mutex allocation
+** routines with a wrapper used to track mutex usage for performance
+** profiling or testing, for example.   ^If SQLite is compiled with
+** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
+** the entire mutexing subsystem is omitted from the build and hence calls to
+** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
+** return [SQLITE_ERROR].</dd>
+**
+** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
+** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
+** the default size of lookaside memory on each [database connection].
+** The first argument is the
+** size of each lookaside buffer slot and the second is the number of
+** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
+** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
+** option to [sqlite3_db_config()] can be used to change the lookaside
+** configuration on individual connections.)^ </dd>
+**
+** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
+** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
+** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
+** the interface to a custom page cache implementation.)^
+** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
+**
+** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
+** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
+** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
+** the current page cache implementation into that object.)^ </dd>
+**
+** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
+** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
+** global [error log].
+** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
+** function with a call signature of void(*)(void*,int,const char*),
+** and a pointer to void. ^If the function pointer is not NULL, it is
+** invoked by [sqlite3_log()] to process each logging event.  ^If the
+** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
+** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
+** passed through as the first parameter to the application-defined logger
+** function whenever that function is invoked.  ^The second parameter to
+** the logger function is a copy of the first parameter to the corresponding
+** [sqlite3_log()] call and is intended to be a [result code] or an
+** [extended result code].  ^The third parameter passed to the logger is
+** log message after formatting via [sqlite3_snprintf()].
+** The SQLite logging interface is not reentrant; the logger function
+** supplied by the application must not invoke any SQLite interface.
+** In a multi-threaded application, the application-defined logger
+** function must be threadsafe. </dd>
+**
+** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
+** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
+** If non-zero, then URI handling is globally enabled. If the parameter is zero,
+** then URI handling is globally disabled.)^ ^If URI handling is globally
+** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
+** [sqlite3_open16()] or
+** specified as part of [ATTACH] commands are interpreted as URIs, regardless
+** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
+** connection is opened. ^If it is globally disabled, filenames are
+** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
+** database connection is opened. ^(By default, URI handling is globally
+** disabled. The default value may be changed by compiling with the
+** [SQLITE_USE_URI] symbol defined.)^
+**
+** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
+** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
+** argument which is interpreted as a boolean in order to enable or disable
+** the use of covering indices for full table scans in the query optimizer.
+** ^The default setting is determined
+** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
+** if that compile-time option is omitted.
+** The ability to disable the use of covering indices for full table scans
+** is because some incorrectly coded legacy applications might malfunction
+** when the optimization is enabled.  Providing the ability to
+** disable the optimization allows the older, buggy application code to work
+** without change even with newer versions of SQLite.
+**
+** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
+** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
+** <dd> These options are obsolete and should not be used by new code.
+** They are retained for backwards compatibility but are now no-ops.
+** </dd>
+**
+** [[SQLITE_CONFIG_SQLLOG]]
+** <dt>SQLITE_CONFIG_SQLLOG
+** <dd>This option is only available if sqlite is compiled with the
+** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
+** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
+** The second should be of type (void*). The callback is invoked by the library
+** in three separate circumstances, identified by the value passed as the
+** fourth parameter. If the fourth parameter is 0, then the database connection
+** passed as the second argument has just been opened. The third argument
+** points to a buffer containing the name of the main database file. If the
+** fourth parameter is 1, then the SQL statement that the third parameter
+** points to has just been executed. Or, if the fourth parameter is 2, then
+** the connection being passed as the second parameter is being closed. The
+** third parameter is passed NULL In this case.  An example of using this
+** configuration option can be seen in the "test_sqllog.c" source file in
+** the canonical SQLite source tree.</dd>
+**
+** [[SQLITE_CONFIG_MMAP_SIZE]]
+** <dt>SQLITE_CONFIG_MMAP_SIZE
+** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
+** that are the default mmap size limit (the default setting for
+** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
+** ^The default setting can be overridden by each database connection using
+** either the [PRAGMA mmap_size] command, or by using the
+** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
+** will be silently truncated if necessary so that it does not exceed the
+** compile-time maximum mmap size set by the
+** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
+** ^If either argument to this option is negative, then that argument is
+** changed to its compile-time default.
+**
+** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
+** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
+** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
+** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
+** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
+** that specifies the maximum size of the created heap.
+**
+** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
+** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
+** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
+** is a pointer to an integer and writes into that integer the number of extra
+** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
+** The amount of extra space required can change depending on the compiler,
+** target platform, and SQLite version.
+**
+** [[SQLITE_CONFIG_PMASZ]]
+** <dt>SQLITE_CONFIG_PMASZ
+** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
+** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
+** sorter to that integer.  The default minimum PMA Size is set by the
+** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
+** to help with sort operations when multithreaded sorting
+** is enabled (using the [PRAGMA threads] command) and the amount of content
+** to be sorted exceeds the page size times the minimum of the
+** [PRAGMA cache_size] setting and this value.
+**
+** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
+** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
+** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
+** becomes the [statement journal] spill-to-disk threshold.
+** [Statement journals] are held in memory until their size (in bytes)
+** exceeds this threshold, at which point they are written to disk.
+** Or if the threshold is -1, statement journals are always held
+** exclusively in memory.
+** Since many statement journals never become large, setting the spill
+** threshold to a value such as 64KiB can greatly reduce the amount of
+** I/O required to support statement rollback.
+** The default value for this setting is controlled by the
+** [SQLITE_STMTJRNL_SPILL] compile-time option.
+**
+** [[SQLITE_CONFIG_SORTERREF_SIZE]]
+** <dt>SQLITE_CONFIG_SORTERREF_SIZE
+** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
+** of type (int) - the new value of the sorter-reference size threshold.
+** Usually, when SQLite uses an external sort to order records according
+** to an ORDER BY clause, all fields required by the caller are present in the
+** sorted records. However, if SQLite determines based on the declared type
+** of a table column that its values are likely to be very large - larger
+** than the configured sorter-reference size threshold - then a reference
+** is stored in each sorted record and the required column values loaded
+** from the database as records are returned in sorted order. The default
+** value for this option is to never use this optimization. Specifying a
+** negative value for this option restores the default behavior.
+** This option is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
+**
+** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
+** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
+** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
+** [sqlite3_int64] parameter which is the default maximum size for an in-memory
+** database created using [sqlite3_deserialize()].  This default maximum
+** size can be adjusted up or down for individual databases using the
+** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
+** configuration setting is never used, then the default maximum is determined
+** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
+** compile-time option is not set, then the default maximum is 1073741824.
+**
+** [[SQLITE_CONFIG_ROWID_IN_VIEW]]
+** <dt>SQLITE_CONFIG_ROWID_IN_VIEW
+** <dd>The SQLITE_CONFIG_ROWID_IN_VIEW option enables or disables the ability
+** for VIEWs to have a ROWID.  The capability can only be enabled if SQLite is
+** compiled with -DSQLITE_ALLOW_ROWID_IN_VIEW, in which case the capability
+** defaults to on.  This configuration option queries the current setting or
+** changes the setting to off or on.  The argument is a pointer to an integer.
+** If that integer initially holds a value of 1, then the ability for VIEWs to
+** have ROWIDs is activated.  If the integer initially holds zero, then the
+** ability is deactivated.  Any other initial value for the integer leaves the
+** setting unchanged.  After changes, if any, the integer is written with
+** a 1 or 0, if the ability for VIEWs to have ROWIDs is on or off.  If SQLite
+** is compiled without -DSQLITE_ALLOW_ROWID_IN_VIEW (which is the usual and
+** recommended case) then the integer is always filled with zero, regardless
+** if its initial value.
+** </dl>
+*/
+#define SQLITE_CONFIG_SINGLETHREAD         1  /* nil */
+#define SQLITE_CONFIG_MULTITHREAD          2  /* nil */
+#define SQLITE_CONFIG_SERIALIZED           3  /* nil */
+#define SQLITE_CONFIG_MALLOC               4  /* sqlite3_mem_methods* */
+#define SQLITE_CONFIG_GETMALLOC            5  /* sqlite3_mem_methods* */
+#define SQLITE_CONFIG_SCRATCH              6  /* No longer used */
+#define SQLITE_CONFIG_PAGECACHE            7  /* void*, int sz, int N */
+#define SQLITE_CONFIG_HEAP                 8  /* void*, int nByte, int min */
+#define SQLITE_CONFIG_MEMSTATUS            9  /* boolean */
+#define SQLITE_CONFIG_MUTEX               10  /* sqlite3_mutex_methods* */
+#define SQLITE_CONFIG_GETMUTEX            11  /* sqlite3_mutex_methods* */
+/* previously SQLITE_CONFIG_CHUNKALLOC    12 which is now unused. */
+#define SQLITE_CONFIG_LOOKASIDE           13  /* int int */
+#define SQLITE_CONFIG_PCACHE              14  /* no-op */
+#define SQLITE_CONFIG_GETPCACHE           15  /* no-op */
+#define SQLITE_CONFIG_LOG                 16  /* xFunc, void* */
+#define SQLITE_CONFIG_URI                 17  /* int */
+#define SQLITE_CONFIG_PCACHE2             18  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_GETPCACHE2          19  /* sqlite3_pcache_methods2* */
+#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
+#define SQLITE_CONFIG_SQLLOG              21  /* xSqllog, void* */
+#define SQLITE_CONFIG_MMAP_SIZE           22  /* sqlite3_int64, sqlite3_int64 */
+#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
+#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
+#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
+#define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
+#define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
+#define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
+#define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
+#define SQLITE_CONFIG_ROWID_IN_VIEW       30  /* int* */
+
+/*
+** CAPI3REF: Database Connection Configuration Options
+**
+** These constants are the available integer configuration options that
+** can be passed as the second parameter to the [sqlite3_db_config()] interface.
+**
+** The [sqlite3_db_config()] interface is a var-args functions.  It takes a
+** variable number of parameters, though always at least two.  The number of
+** parameters passed into sqlite3_db_config() depends on which of these
+** constants is given as the second parameter.  This documentation page
+** refers to parameters beyond the second as "arguments".  Thus, when this
+** page says "the N-th argument" it means "the N-th parameter past the
+** configuration option" or "the (N+2)-th parameter to sqlite3_db_config()".
+**
+** New configuration options may be added in future releases of SQLite.
+** Existing configuration options might be discontinued.  Applications
+** should check the return code from [sqlite3_db_config()] to make sure that
+** the call worked.  ^The [sqlite3_db_config()] interface will return a
+** non-zero [error code] if a discontinued or unsupported configuration option
+** is invoked.
+**
+** <dl>
+** [[SQLITE_DBCONFIG_LOOKASIDE]]
+** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
+** <dd> The SQLITE_DBCONFIG_LOOKASIDE option is used to adjust the
+** configuration of the lookaside memory allocator within a database
+** connection.
+** The arguments to the SQLITE_DBCONFIG_LOOKASIDE option are <i>not</i>
+** in the [DBCONFIG arguments|usual format].
+** The SQLITE_DBCONFIG_LOOKASIDE option takes three arguments, not two,
+** so that a call to [sqlite3_db_config()] that uses SQLITE_DBCONFIG_LOOKASIDE
+** should have a total of five parameters.
+** ^The first argument (the third parameter to [sqlite3_db_config()] is a
+** pointer to a memory buffer to use for lookaside memory.
+** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
+** may be NULL in which case SQLite will allocate the
+** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
+** size of each lookaside buffer slot.  ^The third argument is the number of
+** slots.  The size of the buffer in the first argument must be greater than
+** or equal to the product of the second and third arguments.  The buffer
+** must be aligned to an 8-byte boundary.  ^If the second argument to
+** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
+** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
+** configuration for a database connection can only be changed when that
+** connection is not currently using lookaside memory, or in other words
+** when the "current value" returned by
+** [sqlite3_db_status](D,[SQLITE_DBSTATUS_LOOKASIDE_USED],...) is zero.
+** Any attempt to change the lookaside memory configuration when lookaside
+** memory is in use leaves the configuration unchanged and returns
+** [SQLITE_BUSY].)^</dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
+** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
+** <dd> ^This option is used to enable or disable the enforcement of
+** [foreign key constraints].  This is the same setting that is
+** enabled or disabled by the [PRAGMA foreign_keys] statement.
+** The first argument is an integer which is 0 to disable FK enforcement,
+** positive to enable FK enforcement or negative to leave FK enforcement
+** unchanged.  The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether FK enforcement is off or on
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the FK enforcement setting is not reported back. </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
+** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
+** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
+** There should be two additional arguments.
+** The first argument is an integer which is 0 to disable triggers,
+** positive to enable triggers or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether triggers are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the trigger setting is not reported back.
+**
+** <p>Originally this option disabled all triggers.  ^(However, since
+** SQLite version 3.35.0, TEMP triggers are still allowed even if
+** this option is off.  So, in other words, this option now only disables
+** triggers in the main database schema or in the schemas of [ATTACH]-ed
+** databases.)^ </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
+** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
+** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
+** There must be two additional arguments.
+** The first argument is an integer which is 0 to disable views,
+** positive to enable views or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether views are disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the view setting is not reported back.
+**
+** <p>Originally this option disabled all views.  ^(However, since
+** SQLite version 3.35.0, TEMP views are still allowed even if
+** this option is off.  So, in other words, this option now only disables
+** views in the main database schema or in the schemas of ATTACH-ed
+** databases.)^ </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
+** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
+** <dd> ^This option is used to enable or disable the
+** [fts3_tokenizer()] function which is part of the
+** [FTS3] full-text search engine extension.
+** There must be two additional arguments.
+** The first argument is an integer which is 0 to disable fts3_tokenizer() or
+** positive to enable fts3_tokenizer() or negative to leave the setting
+** unchanged.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
+** following this call.  The second parameter may be a NULL pointer, in
+** which case the new setting is not reported back. </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
+** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
+** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
+** interface independently of the [load_extension()] SQL function.
+** The [sqlite3_enable_load_extension()] API enables or disables both the
+** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
+** There must be two additional arguments.
+** When the first argument to this interface is 1, then only the C-API is
+** enabled and the SQL function remains disabled.  If the first argument to
+** this interface is 0, then both the C-API and the SQL function are disabled.
+** If the first argument is -1, then no changes are made to state of either the
+** C-API or the SQL function.
+** The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
+** is disabled or enabled following this call.  The second parameter may
+** be a NULL pointer, in which case the new setting is not reported back.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
+** <dd> ^This option is used to change the name of the "main" database
+** schema.  This option does not follow the
+** [DBCONFIG arguments|usual SQLITE_DBCONFIG argument format].
+** This option takes exactly one additional argument so that the
+** [sqlite3_db_config()] call has a total of three parameters.  The
+** extra argument must be a pointer to a constant UTF8 string which
+** will become the new schema name in place of "main".  ^SQLite does
+** not make a copy of the new main schema name string, so the application
+** must ensure that the argument passed into SQLITE_DBCONFIG MAINDBNAME
+** is unchanged until after the database connection closes.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
+** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
+** <dd> Usually, when a database in [WAL mode] is closed or detached from a
+** database handle, SQLite checks if if there are other connections to the
+** same database, and if there are no other database connection (if the
+** connection being closed is the last open connection to the database),
+** then SQLite performs a [checkpoint] before closing the connection and
+** deletes the WAL file.  The SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE option can
+** be used to override that behavior. The first argument passed to this
+** operation (the third parameter to [sqlite3_db_config()]) is an integer
+** which is positive to disable checkpoints-on-close, or zero (the default)
+** to enable them, and negative to leave the setting unchanged.
+** The second argument (the fourth parameter) is a pointer to an integer
+** into which is written 0 or 1 to indicate whether checkpoints-on-close
+** have been disabled - 0 if they are not disabled, 1 if they are.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
+** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
+** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
+** a single SQL query statement will always use the same algorithm regardless
+** of values of [bound parameters].)^ The QPSG disables some query optimizations
+** that look at the values of bound parameters, which can make some queries
+** slower.  But the QPSG has the advantage of more predictable behavior.  With
+** the QPSG active, SQLite will always use the same query plan in the field as
+** was used during testing in the lab.
+** The first argument to this setting is an integer which is 0 to disable
+** the QPSG, positive to enable QPSG, or negative to leave the setting
+** unchanged. The second parameter is a pointer to an integer into which
+** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
+** following this call.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
+** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
+** include output for any operations performed by trigger programs. This
+** option is used to set or clear (the default) a flag that governs this
+** behavior. The first parameter passed to this operation is an integer -
+** positive to enable output for trigger programs, or zero to disable it,
+** or negative to leave the setting unchanged.
+** The second parameter is a pointer to an integer into which is written
+** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
+** it is not disabled, 1 if it is.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
+** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
+** [VACUUM] in order to reset a database back to an empty database
+** with no schema and no content. The following process works even for
+** a badly corrupted database file:
+** <ol>
+** <li> If the database connection is newly opened, make sure it has read the
+**      database schema by preparing then discarding some query against the
+**      database, or calling sqlite3_table_column_metadata(), ignoring any
+**      errors.  This step is only necessary if the application desires to keep
+**      the database in WAL mode after the reset if it was in WAL mode before
+**      the reset.
+** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
+** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
+** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
+** </ol>
+** Because resetting a database is destructive and irreversible, the
+** process requires the use of this obscure API and multiple steps to
+** help ensure that it does not happen by accident. Because this
+** feature must be capable of resetting corrupt databases, and
+** shutting down virtual tables may require access to that corrupt
+** storage, the library must abandon any installed virtual tables
+** without calling their xDestroy() methods.
+**
+** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
+** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
+** "defensive" flag for a database connection.  When the defensive
+** flag is enabled, language features that allow ordinary SQL to
+** deliberately corrupt the database file are disabled.  The disabled
+** features include but are not limited to the following:
+** <ul>
+** <li> The [PRAGMA writable_schema=ON] statement.
+** <li> The [PRAGMA journal_mode=OFF] statement.
+** <li> The [PRAGMA schema_version=N] statement.
+** <li> Writes to the [sqlite_dbpage] virtual table.
+** <li> Direct writes to [shadow tables].
+** </ul>
+** </dd>
+**
+** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
+** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
+** "writable_schema" flag. This has the same effect and is logically equivalent
+** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
+** The first argument to this setting is an integer which is 0 to disable
+** the writable_schema, positive to enable writable_schema, or negative to
+** leave the setting unchanged. The second parameter is a pointer to an
+** integer into which is written 0 or 1 to indicate whether the writable_schema
+** is enabled or disabled following this call.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
+** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
+** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
+** the legacy behavior of the [ALTER TABLE RENAME] command such it
+** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
+** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
+** additional information. This feature can also be turned on and off
+** using the [PRAGMA legacy_alter_table] statement.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_DQS_DML]]
+** <dt>SQLITE_DBCONFIG_DQS_DML</dt>
+** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
+** the legacy [double-quoted string literal] misfeature for DML statements
+** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
+** default value of this setting is determined by the [-DSQLITE_DQS]
+** compile-time option.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_DQS_DDL]]
+** <dt>SQLITE_DBCONFIG_DQS_DDL</dt>
+** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
+** the legacy [double-quoted string literal] misfeature for DDL statements,
+** such as CREATE TABLE and CREATE INDEX. The
+** default value of this setting is determined by the [-DSQLITE_DQS]
+** compile-time option.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
+** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</dt>
+** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
+** assume that database schemas are untainted by malicious content.
+** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
+** takes additional defensive steps to protect the application from harm
+** including:
+** <ul>
+** <li> Prohibit the use of SQL functions inside triggers, views,
+** CHECK constraints, DEFAULT clauses, expression indexes,
+** partial indexes, or generated columns
+** unless those functions are tagged with [SQLITE_INNOCUOUS].
+** <li> Prohibit the use of virtual tables inside of triggers or views
+** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
+** </ul>
+** This setting defaults to "on" for legacy compatibility, however
+** all applications are advised to turn it off if possible. This setting
+** can also be controlled using the [PRAGMA trusted_schema] statement.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
+** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</dt>
+** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
+** the legacy file format flag.  When activated, this flag causes all newly
+** created database file to have a schema format version number (the 4-byte
+** integer found at offset 44 into the database header) of 1.  This in turn
+** means that the resulting database file will be readable and writable by
+** any SQLite version back to 3.0.0 ([dateof:3.0.0]).  Without this setting,
+** newly created databases are generally not understandable by SQLite versions
+** prior to 3.3.0 ([dateof:3.3.0]).  As these words are written, there
+** is now scarcely any need to generate database files that are compatible
+** all the way back to version 3.0.0, and so this setting is of little
+** practical use, but is provided so that SQLite can continue to claim the
+** ability to generate new database files that are compatible with  version
+** 3.0.0.
+** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
+** the [VACUUM] command will fail with an obscure error when attempting to
+** process a table with generated columns and a descending index.  This is
+** not considered a bug since SQLite versions 3.3.0 and earlier do not support
+** either generated columns or descending indexes.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_STMT_SCANSTATUS]]
+** <dt>SQLITE_DBCONFIG_STMT_SCANSTATUS</dt>
+** <dd>The SQLITE_DBCONFIG_STMT_SCANSTATUS option is only useful in
+** SQLITE_ENABLE_STMT_SCANSTATUS builds. In this case, it sets or clears
+** a flag that enables collection of the sqlite3_stmt_scanstatus_v2()
+** statistics. For statistics to be collected, the flag must be set on
+** the database handle both when the SQL statement is prepared and when it
+** is stepped. The flag is set (collection of statistics is enabled)
+** by default. <p>This option takes two arguments: an integer and a pointer to
+** an integer..  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the statement scanstatus option.  If the second argument
+** is not NULL, then the value of the statement scanstatus setting after
+** processing the first argument is written into the integer that the second
+** argument points to.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_REVERSE_SCANORDER]]
+** <dt>SQLITE_DBCONFIG_REVERSE_SCANORDER</dt>
+** <dd>The SQLITE_DBCONFIG_REVERSE_SCANORDER option changes the default order
+** in which tables and indexes are scanned so that the scans start at the end
+** and work toward the beginning rather than starting at the beginning and
+** working toward the end. Setting SQLITE_DBCONFIG_REVERSE_SCANORDER is the
+** same as setting [PRAGMA reverse_unordered_selects]. <p>This option takes
+** two arguments which are an integer and a pointer to an integer.  The first
+** argument is 1, 0, or -1 to enable, disable, or leave unchanged the
+** reverse scan order flag, respectively.  If the second argument is not NULL,
+** then 0 or 1 is written into the integer that the second argument points to
+** depending on if the reverse scan order flag is set after processing the
+** first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]]
+** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE option enables or disables
+** the ability of the [ATTACH DATABASE] SQL command to create a new database
+** file if the database filed named in the ATTACH command does not already
+** exist.  This ability of ATTACH to create a new database is enabled by
+** default.  Applications can disable or reenable the ability for ATTACH to
+** create new database files using this DBCONFIG option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the attach-create flag, respectively.  If the second
+** argument is not NULL, then 0 or 1 is written into the integer that the
+** second argument points to depending on if the attach-create flag is set
+** after processing the first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE]]
+** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE option enables or disables the
+** ability of the [ATTACH DATABASE] SQL command to open a database for writing.
+** This capability is enabled by default.  Applications can disable or
+** reenable this capability using the current DBCONFIG option.  If the
+** the this capability is disabled, the [ATTACH] command will still work,
+** but the database will be opened read-only.  If this option is disabled,
+** then the ability to create a new database using [ATTACH] is also disabled,
+** regardless of the value of the [SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]
+** option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the ability to ATTACH another database for writing,
+** respectively.  If the second argument is not NULL, then 0 or 1 is written
+** into the integer to which the second argument points, depending on whether
+** the ability to ATTACH a read/write database is enabled or disabled
+** after processing the first argument.
+** </dd>
+**
+** [[SQLITE_DBCONFIG_ENABLE_COMMENTS]]
+** <dt>SQLITE_DBCONFIG_ENABLE_COMMENTS</dt>
+** <dd>The SQLITE_DBCONFIG_ENABLE_COMMENTS option enables or disables the
+** ability to include comments in SQL text.  Comments are enabled by default.
+** An application can disable or reenable comments in SQL text using this
+** DBCONFIG option.<p>
+** This option takes two arguments which are an integer and a pointer
+** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
+** leave unchanged the ability to use comments in SQL text,
+** respectively.  If the second argument is not NULL, then 0 or 1 is written
+** into the integer that the second argument points to depending on if
+** comments are allowed in SQL text after processing the first argument.
+** </dd>
+**
+** </dl>
+**
+** [[DBCONFIG arguments]] <h3>Arguments To SQLITE_DBCONFIG Options</h3>
+**
+** <p>Most of the SQLITE_DBCONFIG options take two arguments, so that the
+** overall call to [sqlite3_db_config()] has a total of four parameters.
+** The first argument (the third parameter to sqlite3_db_config()) is a integer.
+** The second argument is a pointer to an integer.  If the first argument is 1,
+** then the option becomes enabled.  If the first integer argument is 0, then the
+** option is disabled.  If the first argument is -1, then the option setting
+** is unchanged.  The second argument, the pointer to an integer, may be NULL.
+** If the second argument is not NULL, then a value of 0 or 1 is written into
+** the integer to which the second argument points, depending on whether the
+** setting is disabled or enabled after applying any changes specified by
+** the first argument.
+**
+** <p>While most SQLITE_DBCONFIG options use the argument format
+** described in the previous paragraph, the [SQLITE_DBCONFIG_MAINDBNAME]
+** and [SQLITE_DBCONFIG_LOOKASIDE] options are different.  See the
+** documentation of those exceptional options for details.
+*/
+#define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
+#define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
+#define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
+#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
+#define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
+#define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
+#define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
+#define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
+#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
+#define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
+#define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
+#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
+#define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
+#define SQLITE_DBCONFIG_STMT_SCANSTATUS       1018 /* int int* */
+#define SQLITE_DBCONFIG_REVERSE_SCANORDER     1019 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE  1020 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE   1021 /* int int* */
+#define SQLITE_DBCONFIG_ENABLE_COMMENTS       1022 /* int int* */
+#define SQLITE_DBCONFIG_MAX                   1022 /* Largest DBCONFIG */
+
+/*
+** CAPI3REF: Enable Or Disable Extended Result Codes
+** METHOD: sqlite3
+**
+** ^The sqlite3_extended_result_codes() routine enables or disables the
+** [extended result codes] feature of SQLite. ^The extended result
+** codes are disabled by default for historical compatibility.
+*/
+SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
+
+/*
+** CAPI3REF: Last Insert Rowid
+** METHOD: sqlite3
+**
+** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
+** has a unique 64-bit signed
+** integer key called the [ROWID | "rowid"]. ^The rowid is always available
+** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
+** names are not also used by explicitly declared columns. ^If
+** the table has a column of type [INTEGER PRIMARY KEY] then that column
+** is another alias for the rowid.
+**
+** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
+** the most recent successful [INSERT] into a rowid table or [virtual table]
+** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
+** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
+** on the database connection D, then sqlite3_last_insert_rowid(D) returns
+** zero.
+**
+** As well as being set automatically as rows are inserted into database
+** tables, the value returned by this function may be set explicitly by
+** [sqlite3_set_last_insert_rowid()]
+**
+** Some virtual table implementations may INSERT rows into rowid tables as
+** part of committing a transaction (e.g. to flush data accumulated in memory
+** to disk). In this case subsequent calls to this function return the rowid
+** associated with these internal INSERT operations, which leads to
+** unintuitive results. Virtual table implementations that do write to rowid
+** tables in this way can avoid this problem by restoring the original
+** rowid value using [sqlite3_set_last_insert_rowid()] before returning
+** control to the user.
+**
+** ^(If an [INSERT] occurs within a trigger then this routine will
+** return the [rowid] of the inserted row as long as the trigger is
+** running. Once the trigger program ends, the value returned
+** by this routine reverts to what it was before the trigger was fired.)^
+**
+** ^An [INSERT] that fails due to a constraint violation is not a
+** successful [INSERT] and does not change the value returned by this
+** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
+** and INSERT OR ABORT make no changes to the return value of this
+** routine when their insertion fails.  ^(When INSERT OR REPLACE
+** encounters a constraint violation, it does not fail.  The
+** INSERT continues to completion after deleting rows that caused
+** the constraint problem so INSERT OR REPLACE will always change
+** the return value of this interface.)^
+**
+** ^For the purposes of this routine, an [INSERT] is considered to
+** be successful even if it is subsequently rolled back.
+**
+** This function is accessible to SQL statements via the
+** [last_insert_rowid() SQL function].
+**
+** If a separate thread performs a new [INSERT] on the same
+** database connection while the [sqlite3_last_insert_rowid()]
+** function is running and thus changes the last insert [rowid],
+** then the value returned by [sqlite3_last_insert_rowid()] is
+** unpredictable and might not equal either the old or the new
+** last insert [rowid].
+*/
+SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
+
+/*
+** CAPI3REF: Set the Last Insert Rowid value.
+** METHOD: sqlite3
+**
+** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
+** set the value returned by calling sqlite3_last_insert_rowid(D) to R
+** without inserting a row into the database.
+*/
+SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
+
+/*
+** CAPI3REF: Count The Number Of Rows Modified
+** METHOD: sqlite3
+**
+** ^These functions return the number of rows modified, inserted or
+** deleted by the most recently completed INSERT, UPDATE or DELETE
+** statement on the database connection specified by the only parameter.
+** The two functions are identical except for the type of the return value
+** and that if the number of rows modified by the most recent INSERT, UPDATE,
+** or DELETE is greater than the maximum value supported by type "int", then
+** the return value of sqlite3_changes() is undefined. ^Executing any other
+** type of SQL statement does not modify the value returned by these functions.
+** For the purposes of this interface, a CREATE TABLE AS SELECT statement
+** does not count as an INSERT, UPDATE or DELETE statement and hence the rows
+** added to the new table by the CREATE TABLE AS SELECT statement are not
+** counted.
+**
+** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
+** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
+** [foreign key actions] or [REPLACE] constraint resolution are not counted.
+**
+** Changes to a view that are intercepted by
+** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
+** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
+** DELETE statement run on a view is always zero. Only changes made to real
+** tables are counted.
+**
+** Things are more complicated if the sqlite3_changes() function is
+** executed while a trigger program is running. This may happen if the
+** program uses the [changes() SQL function], or if some other callback
+** function invokes sqlite3_changes() directly. Essentially:
+**
+** <ul>
+**   <li> ^(Before entering a trigger program the value returned by
+**        sqlite3_changes() function is saved. After the trigger program
+**        has finished, the original value is restored.)^
+**
+**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
+**        statement sets the value returned by sqlite3_changes()
+**        upon completion as normal. Of course, this value will not include
+**        any changes performed by sub-triggers, as the sqlite3_changes()
+**        value will be saved and restored after each sub-trigger has run.)^
+** </ul>
+**
+** ^This means that if the changes() SQL function (or similar) is used
+** by the first INSERT, UPDATE or DELETE statement within a trigger, it
+** returns the value as set when the calling statement began executing.
+** ^If it is used by the second or subsequent such statement within a trigger
+** program, the value returned reflects the number of rows modified by the
+** previous INSERT, UPDATE or DELETE statement within the same trigger.
+**
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_changes()] is running then the value returned
+** is unpredictable and not meaningful.
+**
+** See also:
+** <ul>
+** <li> the [sqlite3_total_changes()] interface
+** <li> the [count_changes pragma]
+** <li> the [changes() SQL function]
+** <li> the [data_version pragma]
+** </ul>
+*/
+SQLITE_API int sqlite3_changes(sqlite3*);
+SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3*);
+
+/*
+** CAPI3REF: Total Number Of Rows Modified
+** METHOD: sqlite3
+**
+** ^These functions return the total number of rows inserted, modified or
+** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
+** since the database connection was opened, including those executed as
+** part of trigger programs. The two functions are identical except for the
+** type of the return value and that if the number of rows modified by the
+** connection exceeds the maximum value supported by type "int", then
+** the return value of sqlite3_total_changes() is undefined. ^Executing
+** any other type of SQL statement does not affect the value returned by
+** sqlite3_total_changes().
+**
+** ^Changes made as part of [foreign key actions] are included in the
+** count, but those made as part of REPLACE constraint resolution are
+** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
+** are not counted.
+**
+** The [sqlite3_total_changes(D)] interface only reports the number
+** of rows that changed due to SQL statement run against database
+** connection D.  Any changes by other database connections are ignored.
+** To detect changes against a database file from other database
+** connections use the [PRAGMA data_version] command or the
+** [SQLITE_FCNTL_DATA_VERSION] [file control].
+**
+** If a separate thread makes changes on the same database connection
+** while [sqlite3_total_changes()] is running then the value
+** returned is unpredictable and not meaningful.
+**
+** See also:
+** <ul>
+** <li> the [sqlite3_changes()] interface
+** <li> the [count_changes pragma]
+** <li> the [changes() SQL function]
+** <li> the [data_version pragma]
+** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
+** </ul>
+*/
+SQLITE_API int sqlite3_total_changes(sqlite3*);
+SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3*);
+
+/*
+** CAPI3REF: Interrupt A Long-Running Query
+** METHOD: sqlite3
+**
+** ^This function causes any pending database operation to abort and
+** return at its earliest opportunity. This routine is typically
+** called in response to a user action such as pressing "Cancel"
+** or Ctrl-C where the user wants a long query operation to halt
+** immediately.
+**
+** ^It is safe to call this routine from a thread different from the
+** thread that is currently running the database operation.  But it
+** is not safe to call this routine with a [database connection] that
+** is closed or might close before sqlite3_interrupt() returns.
+**
+** ^If an SQL operation is very nearly finished at the time when
+** sqlite3_interrupt() is called, then it might not have an opportunity
+** to be interrupted and might continue to completion.
+**
+** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
+** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
+** that is inside an explicit transaction, then the entire transaction
+** will be rolled back automatically.
+**
+** ^The sqlite3_interrupt(D) call is in effect until all currently running
+** SQL statements on [database connection] D complete.  ^Any new SQL statements
+** that are started after the sqlite3_interrupt() call and before the
+** running statement count reaches zero are interrupted as if they had been
+** running prior to the sqlite3_interrupt() call.  ^New SQL statements
+** that are started after the running statement count reaches zero are
+** not effected by the sqlite3_interrupt().
+** ^A call to sqlite3_interrupt(D) that occurs when there are no running
+** SQL statements is a no-op and has no effect on SQL statements
+** that are started after the sqlite3_interrupt() call returns.
+**
+** ^The [sqlite3_is_interrupted(D)] interface can be used to determine whether
+** or not an interrupt is currently in effect for [database connection] D.
+** It returns 1 if an interrupt is currently in effect, or 0 otherwise.
+*/
+SQLITE_API void sqlite3_interrupt(sqlite3*);
+SQLITE_API int sqlite3_is_interrupted(sqlite3*);
+
+/*
+** CAPI3REF: Determine If An SQL Statement Is Complete
+**
+** These routines are useful during command-line input to determine if the
+** currently entered text seems to form a complete SQL statement or
+** if additional input is needed before sending the text into
+** SQLite for parsing.  ^These routines return 1 if the input string
+** appears to be a complete SQL statement.  ^A statement is judged to be
+** complete if it ends with a semicolon token and is not a prefix of a
+** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
+** string literals or quoted identifier names or comments are not
+** independent tokens (they are part of the token in which they are
+** embedded) and thus do not count as a statement terminator.  ^Whitespace
+** and comments that follow the final semicolon are ignored.
+**
+** ^These routines return 0 if the statement is incomplete.  ^If a
+** memory allocation fails, then SQLITE_NOMEM is returned.
+**
+** ^These routines do not parse the SQL statements thus
+** will not detect syntactically incorrect SQL.
+**
+** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
+** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
+** automatically by sqlite3_complete16().  If that initialization fails,
+** then the return value from sqlite3_complete16() will be non-zero
+** regardless of whether or not the input SQL is complete.)^
+**
+** The input to [sqlite3_complete()] must be a zero-terminated
+** UTF-8 string.
+**
+** The input to [sqlite3_complete16()] must be a zero-terminated
+** UTF-16 string in native byte order.
+*/
+SQLITE_API int sqlite3_complete(const char *sql);
+SQLITE_API int sqlite3_complete16(const void *sql);
+
+/*
+** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
+** KEYWORDS: {busy-handler callback} {busy handler}
+** METHOD: sqlite3
+**
+** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
+** that might be invoked with argument P whenever
+** an attempt is made to access a database table associated with
+** [database connection] D when another thread
+** or process has the table locked.
+** The sqlite3_busy_handler() interface is used to implement
+** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
+**
+** ^If the busy callback is NULL, then [SQLITE_BUSY]
+** is returned immediately upon encountering the lock.  ^If the busy callback
+** is not NULL, then the callback might be invoked with two arguments.
+**
+** ^The first argument to the busy handler is a copy of the void* pointer which
+** is the third argument to sqlite3_busy_handler().  ^The second argument to
+** the busy handler callback is the number of times that the busy handler has
+** been invoked previously for the same locking event.  ^If the
+** busy callback returns 0, then no additional attempts are made to
+** access the database and [SQLITE_BUSY] is returned
+** to the application.
+** ^If the callback returns non-zero, then another attempt
+** is made to access the database and the cycle repeats.
+**
+** The presence of a busy handler does not guarantee that it will be invoked
+** when there is lock contention. ^If SQLite determines that invoking the busy
+** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
+** to the application instead of invoking the
+** busy handler.
+** Consider a scenario where one process is holding a read lock that
+** it is trying to promote to a reserved lock and
+** a second process is holding a reserved lock that it is trying
+** to promote to an exclusive lock.  The first process cannot proceed
+** because it is blocked by the second and the second process cannot
+** proceed because it is blocked by the first.  If both processes
+** invoke the busy handlers, neither will make any progress.  Therefore,
+** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
+** will induce the first process to release its read lock and allow
+** the second process to proceed.
+**
+** ^The default busy callback is NULL.
+**
+** ^(There can only be a single busy handler defined for each
+** [database connection].  Setting a new busy handler clears any
+** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
+** or evaluating [PRAGMA busy_timeout=N] will change the
+** busy handler and thus clear any previously set busy handler.
+**
+** The busy callback should not take any actions which modify the
+** database connection that invoked the busy handler.  In other words,
+** the busy handler is not reentrant.  Any such actions
+** result in undefined behavior.
+**
+** A busy handler must not close the database connection
+** or [prepared statement] that invoked the busy handler.
+*/
+SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
+
+/*
+** CAPI3REF: Set A Busy Timeout
+** METHOD: sqlite3
+**
+** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
+** for a specified amount of time when a table is locked.  ^The handler
+** will sleep multiple times until at least "ms" milliseconds of sleeping
+** have accumulated.  ^After at least "ms" milliseconds of sleeping,
+** the handler returns 0 which causes [sqlite3_step()] to return
+** [SQLITE_BUSY].
+**
+** ^Calling this routine with an argument less than or equal to zero
+** turns off all busy handlers.
+**
+** ^(There can only be a single busy handler for a particular
+** [database connection] at any given moment.  If another busy handler
+** was defined  (using [sqlite3_busy_handler()]) prior to calling
+** this routine, that other busy handler is cleared.)^
+**
+** See also:  [PRAGMA busy_timeout]
+*/
+SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
+
+/*
+** CAPI3REF: Convenience Routines For Running Queries
+** METHOD: sqlite3
+**
+** This is a legacy interface that is preserved for backwards compatibility.
+** Use of this interface is not recommended.
+**
+** Definition: A <b>result table</b> is memory data structure created by the
+** [sqlite3_get_table()] interface.  A result table records the
+** complete query results from one or more queries.
+**
+** The table conceptually has a number of rows and columns.  But
+** these numbers are not part of the result table itself.  These
+** numbers are obtained separately.  Let N be the number of rows
+** and M be the number of columns.
+**
+** A result table is an array of pointers to zero-terminated UTF-8 strings.
+** There are (N+1)*M elements in the array.  The first M pointers point
+** to zero-terminated strings that  contain the names of the columns.
+** The remaining entries all point to query results.  NULL values result
+** in NULL pointers.  All other values are in their UTF-8 zero-terminated
+** string representation as returned by [sqlite3_column_text()].
+**
+** A result table might consist of one or more memory allocations.
+** It is not safe to pass a result table directly to [sqlite3_free()].
+** A result table should be deallocated using [sqlite3_free_table()].
+**
+** ^(As an example of the result table format, suppose a query result
+** is as follows:
+**
+** <blockquote><pre>
+**        Name        | Age
+**        -----------------------
+**        Alice       | 43
+**        Bob         | 28
+**        Cindy       | 21
+** </pre></blockquote>
+**
+** There are two columns (M==2) and three rows (N==3).  Thus the
+** result table has 8 entries.  Suppose the result table is stored
+** in an array named azResult.  Then azResult holds this content:
+**
+** <blockquote><pre>
+**        azResult[0] = "Name";
+**        azResult[1] = "Age";
+**        azResult[2] = "Alice";
+**        azResult[3] = "43";
+**        azResult[4] = "Bob";
+**        azResult[5] = "28";
+**        azResult[6] = "Cindy";
+**        azResult[7] = "21";
+** </pre></blockquote>)^
+**
+** ^The sqlite3_get_table() function evaluates one or more
+** semicolon-separated SQL statements in the zero-terminated UTF-8
+** string of its 2nd parameter and returns a result table to the
+** pointer given in its 3rd parameter.
+**
+** After the application has finished with the result from sqlite3_get_table(),
+** it must pass the result table pointer to sqlite3_free_table() in order to
+** release the memory that was malloced.  Because of the way the
+** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
+** function must not try to call [sqlite3_free()] directly.  Only
+** [sqlite3_free_table()] is able to release the memory properly and safely.
+**
+** The sqlite3_get_table() interface is implemented as a wrapper around
+** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
+** to any internal data structures of SQLite.  It uses only the public
+** interface defined here.  As a consequence, errors that occur in the
+** wrapper layer outside of the internal [sqlite3_exec()] call are not
+** reflected in subsequent calls to [sqlite3_errcode()] or
+** [sqlite3_errmsg()].
+*/
+SQLITE_API int sqlite3_get_table(
+  sqlite3 *db,          /* An open database */
+  const char *zSql,     /* SQL to be evaluated */
+  char ***pazResult,    /* Results of the query */
+  int *pnRow,           /* Number of result rows written here */
+  int *pnColumn,        /* Number of result columns written here */
+  char **pzErrmsg       /* Error msg written here */
+);
+SQLITE_API void sqlite3_free_table(char **result);
+
+/*
+** CAPI3REF: Formatted String Printing Functions
+**
+** These routines are work-alikes of the "printf()" family of functions
+** from the standard C library.
+** These routines understand most of the common formatting options from
+** the standard library printf()
+** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
+** See the [built-in printf()] documentation for details.
+**
+** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
+** results into memory obtained from [sqlite3_malloc64()].
+** The strings returned by these two routines should be
+** released by [sqlite3_free()].  ^Both routines return a
+** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
+** memory to hold the resulting string.
+**
+** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
+** the standard C library.  The result is written into the
+** buffer supplied as the second parameter whose size is given by
+** the first parameter. Note that the order of the
+** first two parameters is reversed from snprintf().)^  This is an
+** historical accident that cannot be fixed without breaking
+** backwards compatibility.  ^(Note also that sqlite3_snprintf()
+** returns a pointer to its buffer instead of the number of
+** characters actually written into the buffer.)^  We admit that
+** the number of characters written would be a more useful return
+** value but we cannot change the implementation of sqlite3_snprintf()
+** now without breaking compatibility.
+**
+** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
+** guarantees that the buffer is always zero-terminated.  ^The first
+** parameter "n" is the total size of the buffer, including space for
+** the zero terminator.  So the longest string that can be completely
+** written will be n-1 characters.
+**
+** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
+**
+** See also:  [built-in printf()], [printf() SQL function]
+*/
+SQLITE_API char *sqlite3_mprintf(const char*,...);
+SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
+SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
+SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
+
+/*
+** CAPI3REF: Memory Allocation Subsystem
+**
+** The SQLite core uses these three routines for all of its own
+** internal memory allocation needs. "Core" in the previous sentence
+** does not include operating-system specific [VFS] implementation.  The
+** Windows VFS uses native malloc() and free() for some operations.
+**
+** ^The sqlite3_malloc() routine returns a pointer to a block
+** of memory at least N bytes in length, where N is the parameter.
+** ^If sqlite3_malloc() is unable to obtain sufficient free
+** memory, it returns a NULL pointer.  ^If the parameter N to
+** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
+** a NULL pointer.
+**
+** ^The sqlite3_malloc64(N) routine works just like
+** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
+** of a signed 32-bit integer.
+**
+** ^Calling sqlite3_free() with a pointer previously returned
+** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
+** that it might be reused.  ^The sqlite3_free() routine is
+** a no-op if is called with a NULL pointer.  Passing a NULL pointer
+** to sqlite3_free() is harmless.  After being freed, memory
+** should neither be read nor written.  Even reading previously freed
+** memory might result in a segmentation fault or other severe error.
+** Memory corruption, a segmentation fault, or other severe error
+** might result if sqlite3_free() is called with a non-NULL pointer that
+** was not obtained from sqlite3_malloc() or sqlite3_realloc().
+**
+** ^The sqlite3_realloc(X,N) interface attempts to resize a
+** prior memory allocation X to be at least N bytes.
+** ^If the X parameter to sqlite3_realloc(X,N)
+** is a NULL pointer then its behavior is identical to calling
+** sqlite3_malloc(N).
+** ^If the N parameter to sqlite3_realloc(X,N) is zero or
+** negative then the behavior is exactly the same as calling
+** sqlite3_free(X).
+** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
+** of at least N bytes in size or NULL if insufficient memory is available.
+** ^If M is the size of the prior allocation, then min(N,M) bytes
+** of the prior allocation are copied into the beginning of buffer returned
+** by sqlite3_realloc(X,N) and the prior allocation is freed.
+** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
+** prior allocation is not freed.
+**
+** ^The sqlite3_realloc64(X,N) interfaces works the same as
+** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
+** of a 32-bit signed integer.
+**
+** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
+** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
+** sqlite3_msize(X) returns the size of that memory allocation in bytes.
+** ^The value returned by sqlite3_msize(X) might be larger than the number
+** of bytes requested when X was allocated.  ^If X is a NULL pointer then
+** sqlite3_msize(X) returns zero.  If X points to something that is not
+** the beginning of memory allocation, or if it points to a formerly
+** valid memory allocation that has now been freed, then the behavior
+** of sqlite3_msize(X) is undefined and possibly harmful.
+**
+** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
+** sqlite3_malloc64(), and sqlite3_realloc64()
+** is always aligned to at least an 8 byte boundary, or to a
+** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
+** option is used.
+**
+** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
+** must be either NULL or else pointers obtained from a prior
+** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
+** not yet been released.
+**
+** The application must not read or write any part of
+** a block of memory after it has been released using
+** [sqlite3_free()] or [sqlite3_realloc()].
+*/
+SQLITE_API void *sqlite3_malloc(int);
+SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
+SQLITE_API void *sqlite3_realloc(void*, int);
+SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
+SQLITE_API void sqlite3_free(void*);
+SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
+
+/*
+** CAPI3REF: Memory Allocator Statistics
+**
+** SQLite provides these two interfaces for reporting on the status
+** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
+** routines, which form the built-in memory allocation subsystem.
+**
+** ^The [sqlite3_memory_used()] routine returns the number of bytes
+** of memory currently outstanding (malloced but not freed).
+** ^The [sqlite3_memory_highwater()] routine returns the maximum
+** value of [sqlite3_memory_used()] since the high-water mark
+** was last reset.  ^The values returned by [sqlite3_memory_used()] and
+** [sqlite3_memory_highwater()] include any overhead
+** added by SQLite in its implementation of [sqlite3_malloc()],
+** but not overhead added by the any underlying system library
+** routines that [sqlite3_malloc()] may call.
+**
+** ^The memory high-water mark is reset to the current value of
+** [sqlite3_memory_used()] if and only if the parameter to
+** [sqlite3_memory_highwater()] is true.  ^The value returned
+** by [sqlite3_memory_highwater(1)] is the high-water mark
+** prior to the reset.
+*/
+SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
+SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
+
+/*
+** CAPI3REF: Pseudo-Random Number Generator
+**
+** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
+** select random [ROWID | ROWIDs] when inserting new records into a table that
+** already uses the largest possible [ROWID].  The PRNG is also used for
+** the built-in random() and randomblob() SQL functions.  This interface allows
+** applications to access the same PRNG for other purposes.
+**
+** ^A call to this routine stores N bytes of randomness into buffer P.
+** ^The P parameter can be a NULL pointer.
+**
+** ^If this routine has not been previously called or if the previous
+** call had N less than one or a NULL pointer for P, then the PRNG is
+** seeded using randomness obtained from the xRandomness method of
+** the default [sqlite3_vfs] object.
+** ^If the previous call to this routine had an N of 1 or more and a
+** non-NULL P then the pseudo-randomness is generated
+** internally and without recourse to the [sqlite3_vfs] xRandomness
+** method.
+*/
+SQLITE_API void sqlite3_randomness(int N, void *P);
+
+/*
+** CAPI3REF: Compile-Time Authorization Callbacks
+** METHOD: sqlite3
+** KEYWORDS: {authorizer callback}
+**
+** ^This routine registers an authorizer callback with a particular
+** [database connection], supplied in the first argument.
+** ^The authorizer callback is invoked as SQL statements are being compiled
+** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
+** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
+** and [sqlite3_prepare16_v3()].  ^At various
+** points during the compilation process, as logic is being created
+** to perform various actions, the authorizer callback is invoked to
+** see if those actions are allowed.  ^The authorizer callback should
+** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
+** specific action but allow the SQL statement to continue to be
+** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
+** rejected with an error.  ^If the authorizer callback returns
+** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
+** then the [sqlite3_prepare_v2()] or equivalent call that triggered
+** the authorizer will fail with an error message.
+**
+** When the callback returns [SQLITE_OK], that means the operation
+** requested is ok.  ^When the callback returns [SQLITE_DENY], the
+** [sqlite3_prepare_v2()] or equivalent call that triggered the
+** authorizer will fail with an error message explaining that
+** access is denied.
+**
+** ^The first parameter to the authorizer callback is a copy of the third
+** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
+** to the callback is an integer [SQLITE_COPY | action code] that specifies
+** the particular action to be authorized. ^The third through sixth parameters
+** to the callback are either NULL pointers or zero-terminated strings
+** that contain additional details about the action to be authorized.
+** Applications must always be prepared to encounter a NULL pointer in any
+** of the third through the sixth parameters of the authorization callback.
+**
+** ^If the action code is [SQLITE_READ]
+** and the callback returns [SQLITE_IGNORE] then the
+** [prepared statement] statement is constructed to substitute
+** a NULL value in place of the table column that would have
+** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
+** return can be used to deny an untrusted user access to individual
+** columns of a table.
+** ^When a table is referenced by a [SELECT] but no column values are
+** extracted from that table (for example in a query like
+** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
+** is invoked once for that table with a column name that is an empty string.
+** ^If the action code is [SQLITE_DELETE] and the callback returns
+** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
+** [truncate optimization] is disabled and all rows are deleted individually.
+**
+** An authorizer is used when [sqlite3_prepare | preparing]
+** SQL statements from an untrusted source, to ensure that the SQL statements
+** do not try to access data they are not allowed to see, or that they do not
+** try to execute malicious statements that damage the database.  For
+** example, an application may allow a user to enter arbitrary
+** SQL queries for evaluation by a database.  But the application does
+** not want the user to be able to make arbitrary changes to the
+** database.  An authorizer could then be put in place while the
+** user-entered SQL is being [sqlite3_prepare | prepared] that
+** disallows everything except [SELECT] statements.
+**
+** Applications that need to process SQL from untrusted sources
+** might also consider lowering resource limits using [sqlite3_limit()]
+** and limiting database size using the [max_page_count] [PRAGMA]
+** in addition to using an authorizer.
+**
+** ^(Only a single authorizer can be in place on a database connection
+** at a time.  Each call to sqlite3_set_authorizer overrides the
+** previous call.)^  ^Disable the authorizer by installing a NULL callback.
+** The authorizer is disabled by default.
+**
+** The authorizer callback must not do anything that will modify
+** the database connection that invoked the authorizer callback.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
+** statement might be re-prepared during [sqlite3_step()] due to a
+** schema change.  Hence, the application should ensure that the
+** correct authorizer callback remains in place during the [sqlite3_step()].
+**
+** ^Note that the authorizer callback is invoked only during
+** [sqlite3_prepare()] or its variants.  Authorization is not
+** performed during statement evaluation in [sqlite3_step()], unless
+** as stated in the previous paragraph, sqlite3_step() invokes
+** sqlite3_prepare_v2() to reprepare a statement after a schema change.
+*/
+SQLITE_API int sqlite3_set_authorizer(
+  sqlite3*,
+  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
+  void *pUserData
+);
+
+/*
+** CAPI3REF: Authorizer Return Codes
+**
+** The [sqlite3_set_authorizer | authorizer callback function] must
+** return either [SQLITE_OK] or one of these two constants in order
+** to signal SQLite whether or not the action is permitted.  See the
+** [sqlite3_set_authorizer | authorizer documentation] for additional
+** information.
+**
+** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
+** returned from the [sqlite3_vtab_on_conflict()] interface.
+*/
+#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
+#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
+
+/*
+** CAPI3REF: Authorizer Action Codes
+**
+** The [sqlite3_set_authorizer()] interface registers a callback function
+** that is invoked to authorize certain SQL statement actions.  The
+** second parameter to the callback is an integer code that specifies
+** what action is being authorized.  These are the integer action codes that
+** the authorizer callback may be passed.
+**
+** These action code values signify what kind of operation is to be
+** authorized.  The 3rd and 4th parameters to the authorization
+** callback function will be parameters or NULL depending on which of these
+** codes is used as the second parameter.  ^(The 5th parameter to the
+** authorizer callback is the name of the database ("main", "temp",
+** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
+** is the name of the inner-most trigger or view that is responsible for
+** the access attempt or NULL if this access attempt is directly from
+** top-level SQL code.
+*/
+/******************************************* 3rd ************ 4th ***********/
+#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
+#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
+#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
+#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
+#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
+#define SQLITE_DELETE                9   /* Table Name      NULL            */
+#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
+#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
+#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
+#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
+#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
+#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
+#define SQLITE_INSERT               18   /* Table Name      NULL            */
+#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
+#define SQLITE_READ                 20   /* Table Name      Column Name     */
+#define SQLITE_SELECT               21   /* NULL            NULL            */
+#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
+#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
+#define SQLITE_ATTACH               24   /* Filename        NULL            */
+#define SQLITE_DETACH               25   /* Database Name   NULL            */
+#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
+#define SQLITE_REINDEX              27   /* Index Name      NULL            */
+#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
+#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
+#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
+#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
+#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
+#define SQLITE_COPY                  0   /* No longer used */
+#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
+
+/*
+** CAPI3REF: Deprecated Tracing And Profiling Functions
+** DEPRECATED
+**
+** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
+** instead of the routines described here.
+**
+** These routines register callback functions that can be used for
+** tracing and profiling the execution of SQL statements.
+**
+** ^The callback function registered by sqlite3_trace() is invoked at
+** various times when an SQL statement is being run by [sqlite3_step()].
+** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
+** SQL statement text as the statement first begins executing.
+** ^(Additional sqlite3_trace() callbacks might occur
+** as each triggered subprogram is entered.  The callbacks for triggers
+** contain a UTF-8 SQL comment that identifies the trigger.)^
+**
+** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
+** the length of [bound parameter] expansion in the output of sqlite3_trace().
+**
+** ^The callback function registered by sqlite3_profile() is invoked
+** as each SQL statement finishes.  ^The profile callback contains
+** the original statement text and an estimate of wall-clock time
+** of how long that statement took to run.  ^The profile callback
+** time is in units of nanoseconds, however the current implementation
+** is only capable of millisecond resolution so the six least significant
+** digits in the time are meaningless.  Future versions of SQLite
+** might provide greater resolution on the profiler callback.  Invoking
+** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
+** profile callback.
+*/
+SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
+   void(*xTrace)(void*,const char*), void*);
+SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
+   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
+
+/*
+** CAPI3REF: SQL Trace Event Codes
+** KEYWORDS: SQLITE_TRACE
+**
+** These constants identify classes of events that can be monitored
+** using the [sqlite3_trace_v2()] tracing logic.  The M argument
+** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
+** the following constants.  ^The first argument to the trace callback
+** is one of the following constants.
+**
+** New tracing constants may be added in future releases.
+**
+** ^A trace callback has four arguments: xCallback(T,C,P,X).
+** ^The T argument is one of the integer type codes above.
+** ^The C argument is a copy of the context pointer passed in as the
+** fourth argument to [sqlite3_trace_v2()].
+** The P and X arguments are pointers whose meanings depend on T.
+**
+** <dl>
+** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
+** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
+** first begins running and possibly at other times during the
+** execution of the prepared statement, such as at the start of each
+** trigger subprogram. ^The P argument is a pointer to the
+** [prepared statement]. ^The X argument is a pointer to a string which
+** is the unexpanded SQL text of the prepared statement or an SQL comment
+** that indicates the invocation of a trigger.  ^The callback can compute
+** the same text that would have been returned by the legacy [sqlite3_trace()]
+** interface by using the X argument when X begins with "--" and invoking
+** [sqlite3_expanded_sql(P)] otherwise.
+**
+** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
+** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
+** information as is provided by the [sqlite3_profile()] callback.
+** ^The P argument is a pointer to the [prepared statement] and the
+** X argument points to a 64-bit integer which is approximately
+** the number of nanoseconds that the prepared statement took to run.
+** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
+**
+** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
+** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
+** statement generates a single row of result.
+** ^The P argument is a pointer to the [prepared statement] and the
+** X argument is unused.
+**
+** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
+** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
+** connection closes.
+** ^The P argument is a pointer to the [database connection] object
+** and the X argument is unused.
+** </dl>
+*/
+#define SQLITE_TRACE_STMT       0x01
+#define SQLITE_TRACE_PROFILE    0x02
+#define SQLITE_TRACE_ROW        0x04
+#define SQLITE_TRACE_CLOSE      0x08
+
+/*
+** CAPI3REF: SQL Trace Hook
+** METHOD: sqlite3
+**
+** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
+** function X against [database connection] D, using property mask M
+** and context pointer P.  ^If the X callback is
+** NULL or if the M mask is zero, then tracing is disabled.  The
+** M argument should be the bitwise OR-ed combination of
+** zero or more [SQLITE_TRACE] constants.
+**
+** ^Each call to either sqlite3_trace(D,X,P) or sqlite3_trace_v2(D,M,X,P)
+** overrides (cancels) all prior calls to sqlite3_trace(D,X,P) or
+** sqlite3_trace_v2(D,M,X,P) for the [database connection] D.  Each
+** database connection may have at most one trace callback.
+**
+** ^The X callback is invoked whenever any of the events identified by
+** mask M occur.  ^The integer return value from the callback is currently
+** ignored, though this may change in future releases.  Callback
+** implementations should return zero to ensure future compatibility.
+**
+** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
+** ^The T argument is one of the [SQLITE_TRACE]
+** constants to indicate why the callback was invoked.
+** ^The C argument is a copy of the context pointer.
+** The P and X arguments are pointers whose meanings depend on T.
+**
+** The sqlite3_trace_v2() interface is intended to replace the legacy
+** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
+** are deprecated.
+*/
+SQLITE_API int sqlite3_trace_v2(
+  sqlite3*,
+  unsigned uMask,
+  int(*xCallback)(unsigned,void*,void*,void*),
+  void *pCtx
+);
+
+/*
+** CAPI3REF: Query Progress Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
+** function X to be invoked periodically during long running calls to
+** [sqlite3_step()] and [sqlite3_prepare()] and similar for
+** database connection D.  An example use for this
+** interface is to keep a GUI updated during a large query.
+**
+** ^The parameter P is passed through as the only parameter to the
+** callback function X.  ^The parameter N is the approximate number of
+** [virtual machine instructions] that are evaluated between successive
+** invocations of the callback X.  ^If N is less than one then the progress
+** handler is disabled.
+**
+** ^Only a single progress handler may be defined at one time per
+** [database connection]; setting a new progress handler cancels the
+** old one.  ^Setting parameter X to NULL disables the progress handler.
+** ^The progress handler is also disabled by setting N to a value less
+** than 1.
+**
+** ^If the progress callback returns non-zero, the operation is
+** interrupted.  This feature can be used to implement a
+** "Cancel" button on a GUI progress dialog box.
+**
+** The progress handler callback must not do anything that will modify
+** the database connection that invoked the progress handler.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** The progress handler callback would originally only be invoked from the
+** bytecode engine.  It still might be invoked during [sqlite3_prepare()]
+** and similar because those routines might force a reparse of the schema
+** which involves running the bytecode engine.  However, beginning with
+** SQLite version 3.41.0, the progress handler callback might also be
+** invoked directly from [sqlite3_prepare()] while analyzing and generating
+** code for complex queries.
+*/
+SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
+
+/*
+** CAPI3REF: Opening A New Database Connection
+** CONSTRUCTOR: sqlite3
+**
+** ^These routines open an SQLite database file as specified by the
+** filename argument. ^The filename argument is interpreted as UTF-8 for
+** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
+** order for sqlite3_open16(). ^(A [database connection] handle is usually
+** returned in *ppDb, even if an error occurs.  The only exception is that
+** if SQLite is unable to allocate memory to hold the [sqlite3] object,
+** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
+** object.)^ ^(If the database is opened (and/or created) successfully, then
+** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
+** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
+** an English language description of the error following a failure of any
+** of the sqlite3_open() routines.
+**
+** ^The default encoding will be UTF-8 for databases created using
+** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
+** created using sqlite3_open16() will be UTF-16 in the native byte order.
+**
+** Whether or not an error occurs when it is opened, resources
+** associated with the [database connection] handle should be released by
+** passing it to [sqlite3_close()] when it is no longer required.
+**
+** The sqlite3_open_v2() interface works like sqlite3_open()
+** except that it accepts two additional parameters for additional control
+** over the new database connection.  ^(The flags parameter to
+** sqlite3_open_v2() must include, at a minimum, one of the following
+** three flag combinations:)^
+**
+** <dl>
+** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
+** <dd>The database is opened in read-only mode.  If the database does
+** not already exist, an error is returned.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
+** <dd>The database is opened for reading and writing if possible, or
+** reading only if the file is write protected by the operating
+** system.  In either case the database must already exist, otherwise
+** an error is returned.  For historical reasons, if opening in
+** read-write mode fails due to OS-level permissions, an attempt is
+** made to open it in read-only mode. [sqlite3_db_readonly()] can be
+** used to determine whether the database is actually
+** read-write.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
+** <dd>The database is opened for reading and writing, and is created if
+** it does not already exist. This is the behavior that is always used for
+** sqlite3_open() and sqlite3_open16().</dd>)^
+** </dl>
+**
+** In addition to the required flags, the following optional flags are
+** also supported:
+**
+** <dl>
+** ^(<dt>[SQLITE_OPEN_URI]</dt>
+** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
+** <dd>The database will be opened as an in-memory database.  The database
+** is named by the "filename" argument for the purposes of cache-sharing,
+** if shared cache mode is enabled, but the "filename" is otherwise ignored.
+** </dd>)^
+**
+** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
+** <dd>The new database connection will use the "multi-thread"
+** [threading mode].)^  This means that separate threads are allowed
+** to use SQLite at the same time, as long as each thread is using
+** a different [database connection].
+**
+** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
+** <dd>The new database connection will use the "serialized"
+** [threading mode].)^  This means the multiple threads can safely
+** attempt to use the same database connection at the same time.
+** (Mutexes will block any actual concurrency, but in this mode
+** there is no harm in trying.)
+**
+** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
+** <dd>The database is opened [shared cache] enabled, overriding
+** the default shared cache setting provided by
+** [sqlite3_enable_shared_cache()].)^
+** The [use of shared cache mode is discouraged] and hence shared cache
+** capabilities may be omitted from many builds of SQLite.  In such cases,
+** this option is a no-op.
+**
+** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
+** <dd>The database is opened [shared cache] disabled, overriding
+** the default shared cache setting provided by
+** [sqlite3_enable_shared_cache()].)^
+**
+** [[OPEN_EXRESCODE]] ^(<dt>[SQLITE_OPEN_EXRESCODE]</dt>
+** <dd>The database connection comes up in "extended result code mode".
+** In other words, the database behaves as if
+** [sqlite3_extended_result_codes(db,1)] were called on the database
+** connection as soon as the connection is created. In addition to setting
+** the extended result code mode, this flag also causes [sqlite3_open_v2()]
+** to return an extended result code.</dd>
+**
+** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
+** <dd>The database filename is not allowed to contain a symbolic link</dd>
+** </dl>)^
+**
+** If the 3rd parameter to sqlite3_open_v2() is not one of the
+** required combinations shown above optionally combined with other
+** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
+** then the behavior is undefined.  Historic versions of SQLite
+** have silently ignored surplus bits in the flags parameter to
+** sqlite3_open_v2(), however that behavior might not be carried through
+** into future versions of SQLite and so applications should not rely
+** upon it.  Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
+** for sqlite3_open_v2().  The SQLITE_OPEN_EXCLUSIVE does *not* cause
+** the open to fail if the database already exists.  The SQLITE_OPEN_EXCLUSIVE
+** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
+** by sqlite3_open_v2().
+**
+** ^The fourth parameter to sqlite3_open_v2() is the name of the
+** [sqlite3_vfs] object that defines the operating system interface that
+** the new database connection should use.  ^If the fourth parameter is
+** a NULL pointer then the default [sqlite3_vfs] object is used.
+**
+** ^If the filename is ":memory:", then a private, temporary in-memory database
+** is created for the connection.  ^This in-memory database will vanish when
+** the database connection is closed.  Future versions of SQLite might
+** make use of additional special filenames that begin with the ":" character.
+** It is recommended that when a database filename actually does begin with
+** a ":" character you should prefix the filename with a pathname such as
+** "./" to avoid ambiguity.
+**
+** ^If the filename is an empty string, then a private, temporary
+** on-disk database will be created.  ^This private database will be
+** automatically deleted as soon as the database connection is closed.
+**
+** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
+**
+** ^If [URI filename] interpretation is enabled, and the filename argument
+** begins with "file:", then the filename is interpreted as a URI. ^URI
+** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
+** set in the third argument to sqlite3_open_v2(), or if it has
+** been enabled globally using the [SQLITE_CONFIG_URI] option with the
+** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
+** URI filename interpretation is turned off
+** by default, but future releases of SQLite might enable URI filename
+** interpretation by default.  See "[URI filenames]" for additional
+** information.
+**
+** URI filenames are parsed according to RFC 3986. ^If the URI contains an
+** authority, then it must be either an empty string or the string
+** "localhost". ^If the authority is not an empty string or "localhost", an
+** error is returned to the caller. ^The fragment component of a URI, if
+** present, is ignored.
+**
+** ^SQLite uses the path component of the URI as the name of the disk file
+** which contains the database. ^If the path begins with a '/' character,
+** then it is interpreted as an absolute path. ^If the path does not begin
+** with a '/' (meaning that the authority section is omitted from the URI)
+** then the path is interpreted as a relative path.
+** ^(On windows, the first component of an absolute path
+** is a drive specification (e.g. "C:").)^
+**
+** [[core URI query parameters]]
+** The query component of a URI may contain parameters that are interpreted
+** either by SQLite itself, or by a [VFS | custom VFS implementation].
+** SQLite and its built-in [VFSes] interpret the
+** following query parameters:
+**
+** <ul>
+**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
+**     a VFS object that provides the operating system interface that should
+**     be used to access the database file on disk. ^If this option is set to
+**     an empty string the default VFS object is used. ^Specifying an unknown
+**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
+**     present, then the VFS specified by the option takes precedence over
+**     the value passed as the fourth parameter to sqlite3_open_v2().
+**
+**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
+**     "rwc", or "memory". Attempting to set it to any other value is
+**     an error)^.
+**     ^If "ro" is specified, then the database is opened for read-only
+**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
+**     third argument to sqlite3_open_v2(). ^If the mode option is set to
+**     "rw", then the database is opened for read-write (but not create)
+**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
+**     been set. ^Value "rwc" is equivalent to setting both
+**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
+**     set to "memory" then a pure [in-memory database] that never reads
+**     or writes from disk is used. ^It is an error to specify a value for
+**     the mode parameter that is less restrictive than that specified by
+**     the flags passed in the third parameter to sqlite3_open_v2().
+**
+**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
+**     "private". ^Setting it to "shared" is equivalent to setting the
+**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
+**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
+**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
+**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
+**     a URI filename, its value overrides any behavior requested by setting
+**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
+**
+**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
+**     [powersafe overwrite] property does or does not apply to the
+**     storage media on which the database file resides.
+**
+**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
+**     which if set disables file locking in rollback journal modes.  This
+**     is useful for accessing a database on a filesystem that does not
+**     support locking.  Caution:  Database corruption might result if two
+**     or more processes write to the same database and any one of those
+**     processes uses nolock=1.
+**
+**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
+**     parameter that indicates that the database file is stored on
+**     read-only media.  ^When immutable is set, SQLite assumes that the
+**     database file cannot be changed, even by a process with higher
+**     privilege, and so the database is opened read-only and all locking
+**     and change detection is disabled.  Caution: Setting the immutable
+**     property on a database file that does in fact change can result
+**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
+**     See also: [SQLITE_IOCAP_IMMUTABLE].
+**
+** </ul>
+**
+** ^Specifying an unknown parameter in the query component of a URI is not an
+** error.  Future versions of SQLite might understand additional query
+** parameters.  See "[query parameters with special meaning to SQLite]" for
+** additional information.
+**
+** [[URI filename examples]] <h3>URI filename examples</h3>
+**
+** <table border="1" align=center cellpadding=5>
+** <tr><th> URI filenames <th> Results
+** <tr><td> file:data.db <td>
+**          Open the file "data.db" in the current directory.
+** <tr><td> file:/home/fred/data.db<br>
+**          file:///home/fred/data.db <br>
+**          file://localhost/home/fred/data.db <br> <td>
+**          Open the database file "/home/fred/data.db".
+** <tr><td> file://darkstar/home/fred/data.db <td>
+**          An error. "darkstar" is not a recognized authority.
+** <tr><td style="white-space:nowrap">
+**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
+**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
+**          C:. Note that the %20 escaping in this example is not strictly
+**          necessary - space characters can be used literally
+**          in URI filenames.
+** <tr><td> file:data.db?mode=ro&cache=private <td>
+**          Open file "data.db" in the current directory for read-only access.
+**          Regardless of whether or not shared-cache mode is enabled by
+**          default, use a private cache.
+** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
+**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
+**          that uses dot-files in place of posix advisory locking.
+** <tr><td> file:data.db?mode=readonly <td>
+**          An error. "readonly" is not a valid option for the "mode" parameter.
+**          Use "ro" instead:  "file:data.db?mode=ro".
+** </table>
+**
+** ^URI hexadecimal escape sequences (%HH) are supported within the path and
+** query components of a URI. A hexadecimal escape sequence consists of a
+** percent sign - "%" - followed by exactly two hexadecimal digits
+** specifying an octet value. ^Before the path or query components of a
+** URI filename are interpreted, they are encoded using UTF-8 and all
+** hexadecimal escape sequences replaced by a single byte containing the
+** corresponding octet. If this process generates an invalid UTF-8 encoding,
+** the results are undefined.
+**
+** <b>Note to Windows users:</b>  The encoding used for the filename argument
+** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
+** codepage is currently defined.  Filenames containing international
+** characters must be converted to UTF-8 prior to passing them into
+** sqlite3_open() or sqlite3_open_v2().
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
+** features that require the use of temporary files may fail.
+**
+** See also: [sqlite3_temp_directory]
+*/
+SQLITE_API int sqlite3_open(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open16(
+  const void *filename,   /* Database filename (UTF-16) */
+  sqlite3 **ppDb          /* OUT: SQLite db handle */
+);
+SQLITE_API int sqlite3_open_v2(
+  const char *filename,   /* Database filename (UTF-8) */
+  sqlite3 **ppDb,         /* OUT: SQLite db handle */
+  int flags,              /* Flags */
+  const char *zVfs        /* Name of VFS module to use */
+);
+
+/*
+** CAPI3REF: Obtain Values For URI Parameters
+**
+** These are utility routines, useful to [VFS|custom VFS implementations],
+** that check if a database file was a URI that contained a specific query
+** parameter, and if so obtains the value of that query parameter.
+**
+** The first parameter to these interfaces (hereafter referred to
+** as F) must be one of:
+** <ul>
+** <li> A database filename pointer created by the SQLite core and
+** passed into the xOpen() method of a VFS implementation, or
+** <li> A filename obtained from [sqlite3_db_filename()], or
+** <li> A new filename constructed using [sqlite3_create_filename()].
+** </ul>
+** If the F parameter is not one of the above, then the behavior is
+** undefined and probably undesirable.  Older versions of SQLite were
+** more tolerant of invalid F parameters than newer versions.
+**
+** If F is a suitable filename (as described in the previous paragraph)
+** and if P is the name of the query parameter, then
+** sqlite3_uri_parameter(F,P) returns the value of the P
+** parameter if it exists or a NULL pointer if P does not appear as a
+** query parameter on F.  If P is a query parameter of F and it
+** has no explicit value, then sqlite3_uri_parameter(F,P) returns
+** a pointer to an empty string.
+**
+** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
+** parameter and returns true (1) or false (0) according to the value
+** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
+** value of query parameter P is one of "yes", "true", or "on" in any
+** case or if the value begins with a non-zero number.  The
+** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
+** query parameter P is one of "no", "false", or "off" in any case or
+** if the value begins with a numeric zero.  If P is not a query
+** parameter on F or if the value of P does not match any of the
+** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
+**
+** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
+** 64-bit signed integer and returns that integer, or D if P does not
+** exist.  If the value of P is something other than an integer, then
+** zero is returned.
+**
+** The sqlite3_uri_key(F,N) returns a pointer to the name (not
+** the value) of the N-th query parameter for filename F, or a NULL
+** pointer if N is less than zero or greater than the number of query
+** parameters minus 1.  The N value is zero-based so N should be 0 to obtain
+** the name of the first query parameter, 1 for the second parameter, and
+** so forth.
+**
+** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
+** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
+** is not a database file pathname pointer that the SQLite core passed
+** into the xOpen VFS method, then the behavior of this routine is undefined
+** and probably undesirable.
+**
+** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
+** parameter can also be the name of a rollback journal file or WAL file
+** in addition to the main database file.  Prior to version 3.31.0, these
+** routines would only work if F was the name of the main database file.
+** When the F parameter is the name of the rollback journal or WAL file,
+** it has access to all the same query parameters as were found on the
+** main database file.
+**
+** See the [URI filename] documentation for additional information.
+*/
+SQLITE_API const char *sqlite3_uri_parameter(sqlite3_filename z, const char *zParam);
+SQLITE_API int sqlite3_uri_boolean(sqlite3_filename z, const char *zParam, int bDefault);
+SQLITE_API sqlite3_int64 sqlite3_uri_int64(sqlite3_filename, const char*, sqlite3_int64);
+SQLITE_API const char *sqlite3_uri_key(sqlite3_filename z, int N);
+
+/*
+** CAPI3REF:  Translate filenames
+**
+** These routines are available to [VFS|custom VFS implementations] for
+** translating filenames between the main database file, the journal file,
+** and the WAL file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
+** returns the name of the corresponding database file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** passed by the SQLite core into the VFS, or if F is a database filename
+** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
+** returns the name of the corresponding rollback journal file.
+**
+** If F is the name of an sqlite database file, journal file, or WAL file
+** that was passed by the SQLite core into the VFS, or if F is a database
+** filename obtained from [sqlite3_db_filename()], then
+** sqlite3_filename_wal(F) returns the name of the corresponding
+** WAL file.
+**
+** In all of the above, if F is not the name of a database, journal or WAL
+** filename passed into the VFS from the SQLite core and F is not the
+** return value from [sqlite3_db_filename()], then the result is
+** undefined and is likely a memory access violation.
+*/
+SQLITE_API const char *sqlite3_filename_database(sqlite3_filename);
+SQLITE_API const char *sqlite3_filename_journal(sqlite3_filename);
+SQLITE_API const char *sqlite3_filename_wal(sqlite3_filename);
+
+/*
+** CAPI3REF:  Database File Corresponding To A Journal
+**
+** ^If X is the name of a rollback or WAL-mode journal file that is
+** passed into the xOpen method of [sqlite3_vfs], then
+** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
+** object that represents the main database file.
+**
+** This routine is intended for use in custom [VFS] implementations
+** only.  It is not a general-purpose interface.
+** The argument sqlite3_file_object(X) must be a filename pointer that
+** has been passed into [sqlite3_vfs].xOpen method where the
+** flags parameter to xOpen contains one of the bits
+** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL].  Any other use
+** of this routine results in undefined and probably undesirable
+** behavior.
+*/
+SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
+
+/*
+** CAPI3REF: Create and Destroy VFS Filenames
+**
+** These interfaces are provided for use by [VFS shim] implementations and
+** are not useful outside of that context.
+**
+** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
+** database filename D with corresponding journal file J and WAL file W and
+** with N URI parameters key/values pairs in the array P.  The result from
+** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
+** is safe to pass to routines like:
+** <ul>
+** <li> [sqlite3_uri_parameter()],
+** <li> [sqlite3_uri_boolean()],
+** <li> [sqlite3_uri_int64()],
+** <li> [sqlite3_uri_key()],
+** <li> [sqlite3_filename_database()],
+** <li> [sqlite3_filename_journal()], or
+** <li> [sqlite3_filename_wal()].
+** </ul>
+** If a memory allocation error occurs, sqlite3_create_filename() might
+** return a NULL pointer.  The memory obtained from sqlite3_create_filename(X)
+** must be released by a corresponding call to sqlite3_free_filename(Y).
+**
+** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
+** of 2*N pointers to strings.  Each pair of pointers in this array corresponds
+** to a key and value for a query parameter.  The P parameter may be a NULL
+** pointer if N is zero.  None of the 2*N pointers in the P array may be
+** NULL pointers and key pointers should not be empty strings.
+** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
+** be NULL pointers, though they can be empty strings.
+**
+** The sqlite3_free_filename(Y) routine releases a memory allocation
+** previously obtained from sqlite3_create_filename().  Invoking
+** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
+**
+** If the Y parameter to sqlite3_free_filename(Y) is anything other
+** than a NULL pointer or a pointer previously acquired from
+** sqlite3_create_filename(), then bad things such as heap
+** corruption or segfaults may occur. The value Y should not be
+** used again after sqlite3_free_filename(Y) has been called.  This means
+** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
+** then the corresponding [sqlite3_module.xClose() method should also be
+** invoked prior to calling sqlite3_free_filename(Y).
+*/
+SQLITE_API sqlite3_filename sqlite3_create_filename(
+  const char *zDatabase,
+  const char *zJournal,
+  const char *zWal,
+  int nParam,
+  const char **azParam
+);
+SQLITE_API void sqlite3_free_filename(sqlite3_filename);
+
+/*
+** CAPI3REF: Error Codes And Messages
+** METHOD: sqlite3
+**
+** ^If the most recent sqlite3_* API call associated with
+** [database connection] D failed, then the sqlite3_errcode(D) interface
+** returns the numeric [result code] or [extended result code] for that
+** API call.
+** ^The sqlite3_extended_errcode()
+** interface is the same except that it always returns the
+** [extended result code] even when extended result codes are
+** disabled.
+**
+** The values returned by sqlite3_errcode() and/or
+** sqlite3_extended_errcode() might change with each API call.
+** Except, there are some interfaces that are guaranteed to never
+** change the value of the error code.  The error-code preserving
+** interfaces include the following:
+**
+** <ul>
+** <li> sqlite3_errcode()
+** <li> sqlite3_extended_errcode()
+** <li> sqlite3_errmsg()
+** <li> sqlite3_errmsg16()
+** <li> sqlite3_error_offset()
+** </ul>
+**
+** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
+** text that describes the error, as either UTF-8 or UTF-16 respectively,
+** or NULL if no error message is available.
+** (See how SQLite handles [invalid UTF] for exceptions to this rule.)
+** ^(Memory to hold the error message string is managed internally.
+** The application does not need to worry about freeing the result.
+** However, the error string might be overwritten or deallocated by
+** subsequent calls to other SQLite interface functions.)^
+**
+** ^The sqlite3_errstr(E) interface returns the English-language text
+** that describes the [result code] E, as UTF-8, or NULL if E is not an
+** result code for which a text error message is available.
+** ^(Memory to hold the error message string is managed internally
+** and must not be freed by the application)^.
+**
+** ^If the most recent error references a specific token in the input
+** SQL, the sqlite3_error_offset() interface returns the byte offset
+** of the start of that token.  ^The byte offset returned by
+** sqlite3_error_offset() assumes that the input SQL is UTF8.
+** ^If the most recent error does not reference a specific token in the input
+** SQL, then the sqlite3_error_offset() function returns -1.
+**
+** When the serialized [threading mode] is in use, it might be the
+** case that a second error occurs on a separate thread in between
+** the time of the first error and the call to these interfaces.
+** When that happens, the second error will be reported since these
+** interfaces always report the most recent result.  To avoid
+** this, each thread can obtain exclusive use of the [database connection] D
+** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
+** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
+** all calls to the interfaces listed here are completed.
+**
+** If an interface fails with SQLITE_MISUSE, that means the interface
+** was invoked incorrectly by the application.  In that case, the
+** error code and message may or may not be set.
+*/
+SQLITE_API int sqlite3_errcode(sqlite3 *db);
+SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
+SQLITE_API const char *sqlite3_errmsg(sqlite3*);
+SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
+SQLITE_API const char *sqlite3_errstr(int);
+SQLITE_API int sqlite3_error_offset(sqlite3 *db);
+
+/*
+** CAPI3REF: Prepared Statement Object
+** KEYWORDS: {prepared statement} {prepared statements}
+**
+** An instance of this object represents a single SQL statement that
+** has been compiled into binary form and is ready to be evaluated.
+**
+** Think of each SQL statement as a separate computer program.  The
+** original SQL text is source code.  A prepared statement object
+** is the compiled object code.  All SQL must be converted into a
+** prepared statement before it can be run.
+**
+** The life-cycle of a prepared statement object usually goes like this:
+**
+** <ol>
+** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
+** <li> Bind values to [parameters] using the sqlite3_bind_*()
+**      interfaces.
+** <li> Run the SQL by calling [sqlite3_step()] one or more times.
+** <li> Reset the prepared statement using [sqlite3_reset()] then go back
+**      to step 2.  Do this zero or more times.
+** <li> Destroy the object using [sqlite3_finalize()].
+** </ol>
+*/
+typedef struct sqlite3_stmt sqlite3_stmt;
+
+/*
+** CAPI3REF: Run-time Limits
+** METHOD: sqlite3
+**
+** ^(This interface allows the size of various constructs to be limited
+** on a connection by connection basis.  The first parameter is the
+** [database connection] whose limit is to be set or queried.  The
+** second parameter is one of the [limit categories] that define a
+** class of constructs to be size limited.  The third parameter is the
+** new limit for that construct.)^
+**
+** ^If the new limit is a negative number, the limit is unchanged.
+** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
+** [limits | hard upper bound]
+** set at compile-time by a C preprocessor macro called
+** [limits | SQLITE_MAX_<i>NAME</i>].
+** (The "_LIMIT_" in the name is changed to "_MAX_".))^
+** ^Attempts to increase a limit above its hard upper bound are
+** silently truncated to the hard upper bound.
+**
+** ^Regardless of whether or not the limit was changed, the
+** [sqlite3_limit()] interface returns the prior value of the limit.
+** ^Hence, to find the current value of a limit without changing it,
+** simply invoke this interface with the third parameter set to -1.
+**
+** Run-time limits are intended for use in applications that manage
+** both their own internal database and also databases that are controlled
+** by untrusted external sources.  An example application might be a
+** web browser that has its own databases for storing history and
+** separate databases controlled by JavaScript applications downloaded
+** off the Internet.  The internal databases can be given the
+** large, default limits.  Databases managed by external sources can
+** be given much smaller limits designed to prevent a denial of service
+** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
+** interface to further control untrusted SQL.  The size of the database
+** created by an untrusted script can be contained using the
+** [max_page_count] [PRAGMA].
+**
+** New run-time limit categories may be added in future releases.
+*/
+SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
+
+/*
+** CAPI3REF: Run-Time Limit Categories
+** KEYWORDS: {limit category} {*limit categories}
+**
+** These constants define various performance limits
+** that can be lowered at run-time using [sqlite3_limit()].
+** The synopsis of the meanings of the various limits is shown below.
+** Additional information is available at [limits | Limits in SQLite].
+**
+** <dl>
+** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
+** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
+**
+** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
+** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
+**
+** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
+** <dd>The maximum number of columns in a table definition or in the
+** result set of a [SELECT] or the maximum number of columns in an index
+** or in an ORDER BY or GROUP BY clause.</dd>)^
+**
+** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
+** <dd>The maximum depth of the parse tree on any expression.</dd>)^
+**
+** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
+** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
+**
+** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
+** <dd>The maximum number of instructions in a virtual machine program
+** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
+** the equivalent tries to allocate space for more than this many opcodes
+** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
+**
+** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
+** <dd>The maximum number of arguments on a function.</dd>)^
+**
+** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
+** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
+**
+** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
+** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
+** <dd>The maximum length of the pattern argument to the [LIKE] or
+** [GLOB] operators.</dd>)^
+**
+** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
+** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
+** <dd>The maximum index number of any [parameter] in an SQL statement.)^
+**
+** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
+** <dd>The maximum depth of recursion for triggers.</dd>)^
+**
+** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
+** <dd>The maximum number of auxiliary worker threads that a single
+** [prepared statement] may start.</dd>)^
+** </dl>
+*/
+#define SQLITE_LIMIT_LENGTH                    0
+#define SQLITE_LIMIT_SQL_LENGTH                1
+#define SQLITE_LIMIT_COLUMN                    2
+#define SQLITE_LIMIT_EXPR_DEPTH                3
+#define SQLITE_LIMIT_COMPOUND_SELECT           4
+#define SQLITE_LIMIT_VDBE_OP                   5
+#define SQLITE_LIMIT_FUNCTION_ARG              6
+#define SQLITE_LIMIT_ATTACHED                  7
+#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
+#define SQLITE_LIMIT_VARIABLE_NUMBER           9
+#define SQLITE_LIMIT_TRIGGER_DEPTH            10
+#define SQLITE_LIMIT_WORKER_THREADS           11
+
+/*
+** CAPI3REF: Prepare Flags
+**
+** These constants define various flags that can be passed into
+** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
+** [sqlite3_prepare16_v3()] interfaces.
+**
+** New flags may be added in future releases of SQLite.
+**
+** <dl>
+** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
+** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
+** that the prepared statement will be retained for a long time and
+** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
+** and [sqlite3_prepare16_v3()] assume that the prepared statement will
+** be used just once or at most a few times and then destroyed using
+** [sqlite3_finalize()] relatively soon. The current implementation acts
+** on this hint by avoiding the use of [lookaside memory] so as not to
+** deplete the limited store of lookaside memory. Future versions of
+** SQLite may act on this hint differently.
+**
+** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
+** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
+** to be required for any prepared statement that wanted to use the
+** [sqlite3_normalized_sql()] interface.  However, the
+** [sqlite3_normalized_sql()] interface is now available to all
+** prepared statements, regardless of whether or not they use this
+** flag.
+**
+** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
+** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
+** to return an error (error code SQLITE_ERROR) if the statement uses
+** any virtual tables.
+**
+** [[SQLITE_PREPARE_DONT_LOG]] <dt>SQLITE_PREPARE_DONT_LOG</dt>
+** <dd>The SQLITE_PREPARE_DONT_LOG flag prevents SQL compiler
+** errors from being sent to the error log defined by
+** [SQLITE_CONFIG_LOG].  This can be used, for example, to do test
+** compiles to see if some SQL syntax is well-formed, without generating
+** messages on the global error log when it is not.  If the test compile
+** fails, the sqlite3_prepare_v3() call returns the same error indications
+** with or without this flag; it just omits the call to [sqlite3_log()] that
+** logs the error.
+** </dl>
+*/
+#define SQLITE_PREPARE_PERSISTENT              0x01
+#define SQLITE_PREPARE_NORMALIZE               0x02
+#define SQLITE_PREPARE_NO_VTAB                 0x04
+#define SQLITE_PREPARE_DONT_LOG                0x10
+
+/*
+** CAPI3REF: Compiling An SQL Statement
+** KEYWORDS: {SQL statement compiler}
+** METHOD: sqlite3
+** CONSTRUCTOR: sqlite3_stmt
+**
+** To execute an SQL statement, it must first be compiled into a byte-code
+** program using one of these routines.  Or, in other words, these routines
+** are constructors for the [prepared statement] object.
+**
+** The preferred routine to use is [sqlite3_prepare_v2()].  The
+** [sqlite3_prepare()] interface is legacy and should be avoided.
+** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
+** for special purposes.
+**
+** The use of the UTF-8 interfaces is preferred, as SQLite currently
+** does all parsing using UTF-8.  The UTF-16 interfaces are provided
+** as a convenience.  The UTF-16 interfaces work by converting the
+** input text into UTF-8, then invoking the corresponding UTF-8 interface.
+**
+** The first argument, "db", is a [database connection] obtained from a
+** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
+** [sqlite3_open16()].  The database connection must not have been closed.
+**
+** The second argument, "zSql", is the statement to be compiled, encoded
+** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
+** and sqlite3_prepare_v3()
+** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
+** and sqlite3_prepare16_v3() use UTF-16.
+**
+** ^If the nByte argument is negative, then zSql is read up to the
+** first zero terminator. ^If nByte is positive, then it is the maximum
+** number of bytes read from zSql.  When nByte is positive, zSql is read
+** up to the first zero terminator or until the nByte bytes have been read,
+** whichever comes first.  ^If nByte is zero, then no prepared
+** statement is generated.
+** If the caller knows that the supplied string is nul-terminated, then
+** there is a small performance advantage to passing an nByte parameter that
+** is the number of bytes in the input string <i>including</i>
+** the nul-terminator.
+** Note that nByte measure the length of the input in bytes, not
+** characters, even for the UTF-16 interfaces.
+**
+** ^If pzTail is not NULL then *pzTail is made to point to the first byte
+** past the end of the first SQL statement in zSql.  These routines only
+** compile the first statement in zSql, so *pzTail is left pointing to
+** what remains uncompiled.
+**
+** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
+** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
+** to NULL.  ^If the input text contains no SQL (if the input is an empty
+** string or a comment) then *ppStmt is set to NULL.
+** The calling procedure is responsible for deleting the compiled
+** SQL statement using [sqlite3_finalize()] after it has finished with it.
+** ppStmt may not be NULL.
+**
+** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
+** otherwise an [error code] is returned.
+**
+** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
+** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
+** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
+** are retained for backwards compatibility, but their use is discouraged.
+** ^In the "vX" interfaces, the prepared statement
+** that is returned (the [sqlite3_stmt] object) contains a copy of the
+** original SQL text. This causes the [sqlite3_step()] interface to
+** behave differently in three ways:
+**
+** <ol>
+** <li>
+** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
+** always used to do, [sqlite3_step()] will automatically recompile the SQL
+** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
+** retries will occur before sqlite3_step() gives up and returns an error.
+** </li>
+**
+** <li>
+** ^When an error occurs, [sqlite3_step()] will return one of the detailed
+** [error codes] or [extended error codes].  ^The legacy behavior was that
+** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
+** and the application would have to make a second call to [sqlite3_reset()]
+** in order to find the underlying cause of the problem. With the "v2" prepare
+** interfaces, the underlying reason for the error is returned immediately.
+** </li>
+**
+** <li>
+** ^If the specific value bound to a [parameter | host parameter] in the
+** WHERE clause might influence the choice of query plan for a statement,
+** then the statement will be automatically recompiled, as if there had been
+** a schema change, on the first [sqlite3_step()] call following any change
+** to the [sqlite3_bind_text | bindings] of that [parameter].
+** ^The specific value of a WHERE-clause [parameter] might influence the
+** choice of query plan if the parameter is the left-hand side of a [LIKE]
+** or [GLOB] operator or if the parameter is compared to an indexed column
+** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
+** </li>
+** </ol>
+**
+** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
+** the extra prepFlags parameter, which is a bit array consisting of zero or
+** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
+** sqlite3_prepare_v2() interface works exactly the same as
+** sqlite3_prepare_v3() with a zero prepFlags parameter.
+*/
+SQLITE_API int sqlite3_prepare(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare_v2(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare_v3(
+  sqlite3 *db,            /* Database handle */
+  const char *zSql,       /* SQL statement, UTF-8 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16_v2(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+SQLITE_API int sqlite3_prepare16_v3(
+  sqlite3 *db,            /* Database handle */
+  const void *zSql,       /* SQL statement, UTF-16 encoded */
+  int nByte,              /* Maximum length of zSql in bytes. */
+  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
+  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
+  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
+);
+
+/*
+** CAPI3REF: Retrieving Statement SQL
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
+** SQL text used to create [prepared statement] P if P was
+** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
+** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
+** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
+** string containing the SQL text of prepared statement P with
+** [bound parameters] expanded.
+** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
+** string containing the normalized SQL text of prepared statement P.  The
+** semantics used to normalize a SQL statement are unspecified and subject
+** to change.  At a minimum, literal values will be replaced with suitable
+** placeholders.
+**
+** ^(For example, if a prepared statement is created using the SQL
+** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
+** and parameter :xyz is unbound, then sqlite3_sql() will return
+** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
+** will return "SELECT 2345,NULL".)^
+**
+** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
+** is available to hold the result, or if the result would exceed the
+** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
+**
+** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
+** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
+** option causes sqlite3_expanded_sql() to always return NULL.
+**
+** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
+** are managed by SQLite and are automatically freed when the prepared
+** statement is finalized.
+** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
+** is obtained from [sqlite3_malloc()] and must be freed by the application
+** by passing it to [sqlite3_free()].
+**
+** ^The sqlite3_normalized_sql() interface is only available if
+** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
+*/
+SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
+SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
+#ifdef SQLITE_ENABLE_NORMALIZE
+SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
+#endif
+
+/*
+** CAPI3REF: Determine If An SQL Statement Writes The Database
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
+** and only if the [prepared statement] X makes no direct changes to
+** the content of the database file.
+**
+** Note that [application-defined SQL functions] or
+** [virtual tables] might change the database indirectly as a side effect.
+** ^(For example, if an application defines a function "eval()" that
+** calls [sqlite3_exec()], then the following SQL statement would
+** change the database file through side-effects:
+**
+** <blockquote><pre>
+**    SELECT eval('DELETE FROM t1') FROM t2;
+** </pre></blockquote>
+**
+** But because the [SELECT] statement does not change the database file
+** directly, sqlite3_stmt_readonly() would still return true.)^
+**
+** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
+** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
+** since the statements themselves do not actually modify the database but
+** rather they control the timing of when other statements modify the
+** database.  ^The [ATTACH] and [DETACH] statements also cause
+** sqlite3_stmt_readonly() to return true since, while those statements
+** change the configuration of a database connection, they do not make
+** changes to the content of the database files on disk.
+** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
+** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
+** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
+** sqlite3_stmt_readonly() returns false for those commands.
+**
+** ^This routine returns false if there is any possibility that the
+** statement might change the database file.  ^A false return does
+** not guarantee that the statement will change the database file.
+** ^For example, an UPDATE statement might have a WHERE clause that
+** makes it a no-op, but the sqlite3_stmt_readonly() result would still
+** be false.  ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
+** read-only no-op if the table already exists, but
+** sqlite3_stmt_readonly() still returns false for such a statement.
+**
+** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
+** statement, then sqlite3_stmt_readonly(X) returns the same value as
+** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
+*/
+SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
+** prepared statement S is an EXPLAIN statement, or 2 if the
+** statement S is an EXPLAIN QUERY PLAN.
+** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
+** an ordinary statement or a NULL pointer.
+*/
+SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Change The EXPLAIN Setting For A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** The sqlite3_stmt_explain(S,E) interface changes the EXPLAIN
+** setting for [prepared statement] S.  If E is zero, then S becomes
+** a normal prepared statement.  If E is 1, then S behaves as if
+** its SQL text began with "[EXPLAIN]".  If E is 2, then S behaves as if
+** its SQL text began with "[EXPLAIN QUERY PLAN]".
+**
+** Calling sqlite3_stmt_explain(S,E) might cause S to be reprepared.
+** SQLite tries to avoid a reprepare, but a reprepare might be necessary
+** on the first transition into EXPLAIN or EXPLAIN QUERY PLAN mode.
+**
+** Because of the potential need to reprepare, a call to
+** sqlite3_stmt_explain(S,E) will fail with SQLITE_ERROR if S cannot be
+** reprepared because it was created using [sqlite3_prepare()] instead of
+** the newer [sqlite3_prepare_v2()] or [sqlite3_prepare_v3()] interfaces and
+** hence has no saved SQL text with which to reprepare.
+**
+** Changing the explain setting for a prepared statement does not change
+** the original SQL text for the statement.  Hence, if the SQL text originally
+** began with EXPLAIN or EXPLAIN QUERY PLAN, but sqlite3_stmt_explain(S,0)
+** is called to convert the statement into an ordinary statement, the EXPLAIN
+** or EXPLAIN QUERY PLAN keywords will still appear in the sqlite3_sql(S)
+** output, even though the statement now acts like a normal SQL statement.
+**
+** This routine returns SQLITE_OK if the explain mode is successfully
+** changed, or an error code if the explain mode could not be changed.
+** The explain mode cannot be changed while a statement is active.
+** Hence, it is good practice to call [sqlite3_reset(S)]
+** immediately prior to calling sqlite3_stmt_explain(S,E).
+*/
+SQLITE_API int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode);
+
+/*
+** CAPI3REF: Determine If A Prepared Statement Has Been Reset
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
+** [prepared statement] S has been stepped at least once using
+** [sqlite3_step(S)] but has neither run to completion (returned
+** [SQLITE_DONE] from [sqlite3_step(S)]) nor
+** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
+** interface returns false if S is a NULL pointer.  If S is not a
+** NULL pointer and is not a pointer to a valid [prepared statement]
+** object, then the behavior is undefined and probably undesirable.
+**
+** This interface can be used in combination [sqlite3_next_stmt()]
+** to locate all prepared statements associated with a database
+** connection that are in need of being reset.  This can be used,
+** for example, in diagnostic routines to search for prepared
+** statements that are holding a transaction open.
+*/
+SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Dynamically Typed Value Object
+** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
+**
+** SQLite uses the sqlite3_value object to represent all values
+** that can be stored in a database table. SQLite uses dynamic typing
+** for the values it stores.  ^Values stored in sqlite3_value objects
+** can be integers, floating point values, strings, BLOBs, or NULL.
+**
+** An sqlite3_value object may be either "protected" or "unprotected".
+** Some interfaces require a protected sqlite3_value.  Other interfaces
+** will accept either a protected or an unprotected sqlite3_value.
+** Every interface that accepts sqlite3_value arguments specifies
+** whether or not it requires a protected sqlite3_value.  The
+** [sqlite3_value_dup()] interface can be used to construct a new
+** protected sqlite3_value from an unprotected sqlite3_value.
+**
+** The terms "protected" and "unprotected" refer to whether or not
+** a mutex is held.  An internal mutex is held for a protected
+** sqlite3_value object but no mutex is held for an unprotected
+** sqlite3_value object.  If SQLite is compiled to be single-threaded
+** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
+** or if SQLite is run in one of reduced mutex modes
+** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
+** then there is no distinction between protected and unprotected
+** sqlite3_value objects and they can be used interchangeably.  However,
+** for maximum code portability it is recommended that applications
+** still make the distinction between protected and unprotected
+** sqlite3_value objects even when not strictly required.
+**
+** ^The sqlite3_value objects that are passed as parameters into the
+** implementation of [application-defined SQL functions] are protected.
+** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
+** are protected.
+** ^The sqlite3_value object returned by
+** [sqlite3_column_value()] is unprotected.
+** Unprotected sqlite3_value objects may only be used as arguments
+** to [sqlite3_result_value()], [sqlite3_bind_value()], and
+** [sqlite3_value_dup()].
+** The [sqlite3_value_blob | sqlite3_value_type()] family of
+** interfaces require protected sqlite3_value objects.
+*/
+typedef struct sqlite3_value sqlite3_value;
+
+/*
+** CAPI3REF: SQL Function Context Object
+**
+** The context in which an SQL function executes is stored in an
+** sqlite3_context object.  ^A pointer to an sqlite3_context object
+** is always first parameter to [application-defined SQL functions].
+** The application-defined SQL function implementation will pass this
+** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
+** [sqlite3_aggregate_context()], [sqlite3_user_data()],
+** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
+** and/or [sqlite3_set_auxdata()].
+*/
+typedef struct sqlite3_context sqlite3_context;
+
+/*
+** CAPI3REF: Binding Values To Prepared Statements
+** KEYWORDS: {host parameter} {host parameters} {host parameter name}
+** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
+** METHOD: sqlite3_stmt
+**
+** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
+** literals may be replaced by a [parameter] that matches one of following
+** templates:
+**
+** <ul>
+** <li>  ?
+** <li>  ?NNN
+** <li>  :VVV
+** <li>  @VVV
+** <li>  $VVV
+** </ul>
+**
+** In the templates above, NNN represents an integer literal,
+** and VVV represents an alphanumeric identifier.)^  ^The values of these
+** parameters (also called "host parameter names" or "SQL parameters")
+** can be set using the sqlite3_bind_*() routines defined here.
+**
+** ^The first argument to the sqlite3_bind_*() routines is always
+** a pointer to the [sqlite3_stmt] object returned from
+** [sqlite3_prepare_v2()] or its variants.
+**
+** ^The second argument is the index of the SQL parameter to be set.
+** ^The leftmost SQL parameter has an index of 1.  ^When the same named
+** SQL parameter is used more than once, second and subsequent
+** occurrences have the same index as the first occurrence.
+** ^The index for named parameters can be looked up using the
+** [sqlite3_bind_parameter_index()] API if desired.  ^The index
+** for "?NNN" parameters is the value of NNN.
+** ^The NNN value must be between 1 and the [sqlite3_limit()]
+** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
+**
+** ^The third argument is the value to bind to the parameter.
+** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
+** is ignored and the end result is the same as sqlite3_bind_null().
+** ^If the third parameter to sqlite3_bind_text() is not NULL, then
+** it should be a pointer to well-formed UTF8 text.
+** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
+** it should be a pointer to well-formed UTF16 text.
+** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
+** it should be a pointer to a well-formed unicode string that is
+** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
+** otherwise.
+**
+** [[byte-order determination rules]] ^The byte-order of
+** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
+** found in first character, which is removed, or in the absence of a BOM
+** the byte order is the native byte order of the host
+** machine for sqlite3_bind_text16() or the byte order specified in
+** the 6th parameter for sqlite3_bind_text64().)^
+** ^If UTF16 input text contains invalid unicode
+** characters, then SQLite might change those invalid characters
+** into the unicode replacement character: U+FFFD.
+**
+** ^(In those routines that have a fourth argument, its value is the
+** number of bytes in the parameter.  To be clear: the value is the
+** number of <u>bytes</u> in the value, not the number of characters.)^
+** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
+** is negative, then the length of the string is
+** the number of bytes up to the first zero terminator.
+** If the fourth parameter to sqlite3_bind_blob() is negative, then
+** the behavior is undefined.
+** If a non-negative fourth parameter is provided to sqlite3_bind_text()
+** or sqlite3_bind_text16() or sqlite3_bind_text64() then
+** that parameter must be the byte offset
+** where the NUL terminator would occur assuming the string were NUL
+** terminated.  If any NUL characters occurs at byte offsets less than
+** the value of the fourth parameter then the resulting string value will
+** contain embedded NULs.  The result of expressions involving strings
+** with embedded NULs is undefined.
+**
+** ^The fifth argument to the BLOB and string binding interfaces controls
+** or indicates the lifetime of the object referenced by the third parameter.
+** These three options exist:
+** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
+** with it may be passed. ^It is called to dispose of the BLOB or string even
+** if the call to the bind API fails, except the destructor is not called if
+** the third parameter is a NULL pointer or the fourth parameter is negative.
+** ^ (2) The special constant, [SQLITE_STATIC], may be passed to indicate that
+** the application remains responsible for disposing of the object. ^In this
+** case, the object and the provided pointer to it must remain valid until
+** either the prepared statement is finalized or the same SQL parameter is
+** bound to something else, whichever occurs sooner.
+** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
+** object is to be copied prior to the return from sqlite3_bind_*(). ^The
+** object and pointer to it must remain valid until then. ^SQLite will then
+** manage the lifetime of its private copy.
+**
+** ^The sixth argument to sqlite3_bind_text64() must be one of
+** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
+** to specify the encoding of the text in the third parameter.  If
+** the sixth argument to sqlite3_bind_text64() is not one of the
+** allowed values shown above, or if the text encoding is different
+** from the encoding specified by the sixth parameter, then the behavior
+** is undefined.
+**
+** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
+** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
+** (just an integer to hold its size) while it is being processed.
+** Zeroblobs are intended to serve as placeholders for BLOBs whose
+** content is later written using
+** [sqlite3_blob_open | incremental BLOB I/O] routines.
+** ^A negative value for the zeroblob results in a zero-length BLOB.
+**
+** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
+** [prepared statement] S to have an SQL value of NULL, but to also be
+** associated with the pointer P of type T.  ^D is either a NULL pointer or
+** a pointer to a destructor function for P. ^SQLite will invoke the
+** destructor D with a single argument of P when it is finished using
+** P.  The T parameter should be a static string, preferably a string
+** literal. The sqlite3_bind_pointer() routine is part of the
+** [pointer passing interface] added for SQLite 3.20.0.
+**
+** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
+** for the [prepared statement] or with a prepared statement for which
+** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
+** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
+** routine is passed a [prepared statement] that has been finalized, the
+** result is undefined and probably harmful.
+**
+** ^Bindings are not cleared by the [sqlite3_reset()] routine.
+** ^Unbound parameters are interpreted as NULL.
+**
+** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
+** [error code] if anything goes wrong.
+** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
+** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
+** [SQLITE_MAX_LENGTH].
+** ^[SQLITE_RANGE] is returned if the parameter
+** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
+**
+** See also: [sqlite3_bind_parameter_count()],
+** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
+SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
+                        void(*)(void*));
+SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
+SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
+SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
+SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
+SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
+SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
+SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
+                         void(*)(void*), unsigned char encoding);
+SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
+SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
+SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
+SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
+
+/*
+** CAPI3REF: Number Of SQL Parameters
+** METHOD: sqlite3_stmt
+**
+** ^This routine can be used to find the number of [SQL parameters]
+** in a [prepared statement].  SQL parameters are tokens of the
+** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
+** placeholders for values that are [sqlite3_bind_blob | bound]
+** to the parameters at a later time.
+**
+** ^(This routine actually returns the index of the largest (rightmost)
+** parameter. For all forms except ?NNN, this will correspond to the
+** number of unique parameters.  If parameters of the ?NNN form are used,
+** there may be gaps in the list.)^
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_name()], and
+** [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Name Of A Host Parameter
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_bind_parameter_name(P,N) interface returns
+** the name of the N-th [SQL parameter] in the [prepared statement] P.
+** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
+** respectively.
+** In other words, the initial ":" or "$" or "@" or "?"
+** is included as part of the name.)^
+** ^Parameters of the form "?" without a following integer have no name
+** and are referred to as "nameless" or "anonymous parameters".
+**
+** ^The first host parameter has an index of 1, not 0.
+**
+** ^If the value N is out of range or if the N-th parameter is
+** nameless, then NULL is returned.  ^The returned string is
+** always in UTF-8 encoding even if the named parameter was
+** originally specified as UTF-16 in [sqlite3_prepare16()],
+** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_index()].
+*/
+SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
+
+/*
+** CAPI3REF: Index Of A Parameter With A Given Name
+** METHOD: sqlite3_stmt
+**
+** ^Return the index of an SQL parameter given its name.  ^The
+** index value returned is suitable for use as the second
+** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
+** is returned if no matching parameter is found.  ^The parameter
+** name must be given in UTF-8 even if the original statement
+** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
+** [sqlite3_prepare16_v3()].
+**
+** See also: [sqlite3_bind_blob|sqlite3_bind()],
+** [sqlite3_bind_parameter_count()], and
+** [sqlite3_bind_parameter_name()].
+*/
+SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
+
+/*
+** CAPI3REF: Reset All Bindings On A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
+** the [sqlite3_bind_blob | bindings] on a [prepared statement].
+** ^Use this routine to reset all host parameters to NULL.
+*/
+SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number Of Columns In A Result Set
+** METHOD: sqlite3_stmt
+**
+** ^Return the number of columns in the result set returned by the
+** [prepared statement]. ^If this routine returns 0, that means the
+** [prepared statement] returns no data (for example an [UPDATE]).
+** ^However, just because this routine returns a positive number does not
+** mean that one or more rows of data will be returned.  ^A SELECT statement
+** will always have a positive sqlite3_column_count() but depending on the
+** WHERE clause constraints and the table content, it might return no rows.
+**
+** See also: [sqlite3_data_count()]
+*/
+SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Column Names In A Result Set
+** METHOD: sqlite3_stmt
+**
+** ^These routines return the name assigned to a particular column
+** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
+** interface returns a pointer to a zero-terminated UTF-8 string
+** and sqlite3_column_name16() returns a pointer to a zero-terminated
+** UTF-16 string.  ^The first parameter is the [prepared statement]
+** that implements the [SELECT] statement. ^The second parameter is the
+** column number.  ^The leftmost column is number 0.
+**
+** ^The returned string pointer is valid until either the [prepared statement]
+** is destroyed by [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the next call to
+** sqlite3_column_name() or sqlite3_column_name16() on the same column.
+**
+** ^If sqlite3_malloc() fails during the processing of either routine
+** (for example during a conversion from UTF-8 to UTF-16) then a
+** NULL pointer is returned.
+**
+** ^The name of a result column is the value of the "AS" clause for
+** that column, if there is an AS clause.  If there is no AS clause
+** then the name of the column is unspecified and may change from
+** one release of SQLite to the next.
+*/
+SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
+SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
+
+/*
+** CAPI3REF: Source Of Data In A Query Result
+** METHOD: sqlite3_stmt
+**
+** ^These routines provide a means to determine the database, table, and
+** table column that is the origin of a particular result column in
+** [SELECT] statement.
+** ^The name of the database or table or column can be returned as
+** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
+** the database name, the _table_ routines return the table name, and
+** the origin_ routines return the column name.
+** ^The returned string is valid until the [prepared statement] is destroyed
+** using [sqlite3_finalize()] or until the statement is automatically
+** reprepared by the first call to [sqlite3_step()] for a particular run
+** or until the same information is requested
+** again in a different encoding.
+**
+** ^The names returned are the original un-aliased names of the
+** database, table, and column.
+**
+** ^The first argument to these interfaces is a [prepared statement].
+** ^These functions return information about the Nth result column returned by
+** the statement, where N is the second function argument.
+** ^The left-most column is column 0 for these routines.
+**
+** ^If the Nth column returned by the statement is an expression or
+** subquery and is not a column value, then all of these functions return
+** NULL.  ^These routines might also return NULL if a memory allocation error
+** occurs.  ^Otherwise, they return the name of the attached database, table,
+** or column that query result column was extracted from.
+**
+** ^As with all other SQLite APIs, those whose names end with "16" return
+** UTF-16 encoded strings and the other functions return UTF-8.
+**
+** ^These APIs are only available if the library was compiled with the
+** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
+**
+** If two or more threads call one or more
+** [sqlite3_column_database_name | column metadata interfaces]
+** for the same [prepared statement] and result column
+** at the same time then the results are undefined.
+*/
+SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
+SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
+
+/*
+** CAPI3REF: Declared Datatype Of A Query Result
+** METHOD: sqlite3_stmt
+**
+** ^(The first parameter is a [prepared statement].
+** If this statement is a [SELECT] statement and the Nth column of the
+** returned result set of that [SELECT] is a table column (not an
+** expression or subquery) then the declared type of the table
+** column is returned.)^  ^If the Nth column of the result set is an
+** expression or subquery, then a NULL pointer is returned.
+** ^The returned string is always UTF-8 encoded.
+**
+** ^(For example, given the database schema:
+**
+** CREATE TABLE t1(c1 VARIANT);
+**
+** and the following statement to be compiled:
+**
+** SELECT c1 + 1, c1 FROM t1;
+**
+** this routine would return the string "VARIANT" for the second result
+** column (i==1), and a NULL pointer for the first result column (i==0).)^
+**
+** ^SQLite uses dynamic run-time typing.  ^So just because a column
+** is declared to contain a particular type does not mean that the
+** data stored in that column is of the declared type.  SQLite is
+** strongly typed, but the typing is dynamic not static.  ^Type
+** is associated with individual values, not with the containers
+** used to hold those values.
+*/
+SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
+SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
+
+/*
+** CAPI3REF: Evaluate An SQL Statement
+** METHOD: sqlite3_stmt
+**
+** After a [prepared statement] has been prepared using any of
+** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
+** or [sqlite3_prepare16_v3()] or one of the legacy
+** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
+** must be called one or more times to evaluate the statement.
+**
+** The details of the behavior of the sqlite3_step() interface depend
+** on whether the statement was prepared using the newer "vX" interfaces
+** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
+** [sqlite3_prepare16_v2()] or the older legacy
+** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
+** new "vX" interface is recommended for new applications but the legacy
+** interface will continue to be supported.
+**
+** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
+** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
+** ^With the "v2" interface, any of the other [result codes] or
+** [extended result codes] might be returned as well.
+**
+** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
+** database locks it needs to do its job.  ^If the statement is a [COMMIT]
+** or occurs outside of an explicit transaction, then you can retry the
+** statement.  If the statement is not a [COMMIT] and occurs within an
+** explicit transaction then you should rollback the transaction before
+** continuing.
+**
+** ^[SQLITE_DONE] means that the statement has finished executing
+** successfully.  sqlite3_step() should not be called again on this virtual
+** machine without first calling [sqlite3_reset()] to reset the virtual
+** machine back to its initial state.
+**
+** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
+** is returned each time a new row of data is ready for processing by the
+** caller. The values may be accessed using the [column access functions].
+** sqlite3_step() is called again to retrieve the next row of data.
+**
+** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
+** violation) has occurred.  sqlite3_step() should not be called again on
+** the VM. More information may be found by calling [sqlite3_errmsg()].
+** ^With the legacy interface, a more specific error code (for example,
+** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
+** can be obtained by calling [sqlite3_reset()] on the
+** [prepared statement].  ^In the "v2" interface,
+** the more specific error code is returned directly by sqlite3_step().
+**
+** [SQLITE_MISUSE] means that the this routine was called inappropriately.
+** Perhaps it was called on a [prepared statement] that has
+** already been [sqlite3_finalize | finalized] or on one that had
+** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
+** be the case that the same database connection is being used by two or
+** more threads at the same moment in time.
+**
+** For all versions of SQLite up to and including 3.6.23.1, a call to
+** [sqlite3_reset()] was required after sqlite3_step() returned anything
+** other than [SQLITE_ROW] before any subsequent invocation of
+** sqlite3_step().  Failure to reset the prepared statement using
+** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
+** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
+** sqlite3_step() began
+** calling [sqlite3_reset()] automatically in this circumstance rather
+** than returning [SQLITE_MISUSE].  This is not considered a compatibility
+** break because any application that ever receives an SQLITE_MISUSE error
+** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
+** can be used to restore the legacy behavior.
+**
+** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
+** API always returns a generic error code, [SQLITE_ERROR], following any
+** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
+** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
+** specific [error codes] that better describes the error.
+** We admit that this is a goofy design.  The problem has been fixed
+** with the "v2" interface.  If you prepare all of your SQL statements
+** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
+** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
+** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
+** then the more specific [error codes] are returned directly
+** by sqlite3_step().  The use of the "vX" interfaces is recommended.
+*/
+SQLITE_API int sqlite3_step(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Number of columns in a result set
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_data_count(P) interface returns the number of columns in the
+** current row of the result set of [prepared statement] P.
+** ^If prepared statement P does not have results ready to return
+** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
+** interfaces) then sqlite3_data_count(P) returns 0.
+** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
+** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
+** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
+** will return non-zero if previous call to [sqlite3_step](P) returned
+** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
+** where it always returns zero since each step of that multi-step
+** pragma returns 0 columns of data.
+**
+** See also: [sqlite3_column_count()]
+*/
+SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Fundamental Datatypes
+** KEYWORDS: SQLITE_TEXT
+**
+** ^(Every value in SQLite has one of five fundamental datatypes:
+**
+** <ul>
+** <li> 64-bit signed integer
+** <li> 64-bit IEEE floating point number
+** <li> string
+** <li> BLOB
+** <li> NULL
+** </ul>)^
+**
+** These constants are codes for each of those types.
+**
+** Note that the SQLITE_TEXT constant was also used in SQLite version 2
+** for a completely different meaning.  Software that links against both
+** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
+** SQLITE_TEXT.
+*/
+#define SQLITE_INTEGER  1
+#define SQLITE_FLOAT    2
+#define SQLITE_BLOB     4
+#define SQLITE_NULL     5
+#ifdef SQLITE_TEXT
+# undef SQLITE_TEXT
+#else
+# define SQLITE_TEXT     3
+#endif
+#define SQLITE3_TEXT     3
+
+/*
+** CAPI3REF: Result Values From A Query
+** KEYWORDS: {column access functions}
+** METHOD: sqlite3_stmt
+**
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result
+** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result
+** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result
+** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result
+** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result
+** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result
+** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an
+** [sqlite3_value|unprotected sqlite3_value] object.
+** <tr><td> <td> <td> 
+** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT result in bytes
+** <tr><td><b>sqlite3_column_bytes16  </b>
+** <td>→  <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_column_type</b><td>→<td>Default
+** datatype of the result
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
+** ^These routines return information about a single column of the current
+** result row of a query.  ^In every case the first argument is a pointer
+** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
+** that was returned from [sqlite3_prepare_v2()] or one of its variants)
+** and the second argument is the index of the column for which information
+** should be returned. ^The leftmost column of the result set has the index 0.
+** ^The number of columns in the result can be determined using
+** [sqlite3_column_count()].
+**
+** If the SQL statement does not currently point to a valid row, or if the
+** column index is out of range, the result is undefined.
+** These routines may only be called when the most recent call to
+** [sqlite3_step()] has returned [SQLITE_ROW] and neither
+** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
+** If any of these routines are called after [sqlite3_reset()] or
+** [sqlite3_finalize()] or after [sqlite3_step()] has returned
+** something other than [SQLITE_ROW], the results are undefined.
+** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
+** are called from a different thread while any of these routines
+** are pending, then the results are undefined.
+**
+** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
+** each return the value of a result column in a specific data format.  If
+** the result column is not initially in the requested format (for example,
+** if the query returns an integer but the sqlite3_column_text() interface
+** is used to extract the value) then an automatic type conversion is performed.
+**
+** ^The sqlite3_column_type() routine returns the
+** [SQLITE_INTEGER | datatype code] for the initial data type
+** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
+** The return value of sqlite3_column_type() can be used to decide which
+** of the first six interface should be used to extract the column value.
+** The value returned by sqlite3_column_type() is only meaningful if no
+** automatic type conversions have occurred for the value in question.
+** After a type conversion, the result of calling sqlite3_column_type()
+** is undefined, though harmless.  Future
+** versions of SQLite may change the behavior of sqlite3_column_type()
+** following a type conversion.
+**
+** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
+** or sqlite3_column_bytes16() interfaces can be used to determine the size
+** of that BLOB or string.
+**
+** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
+** the string to UTF-8 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
+**
+** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
+** routine returns the number of bytes in that BLOB or string.
+** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
+** the string to UTF-16 and then returns the number of bytes.
+** ^If the result is a numeric value then sqlite3_column_bytes16() uses
+** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
+** the number of bytes in that string.
+** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
+**
+** ^The values returned by [sqlite3_column_bytes()] and
+** [sqlite3_column_bytes16()] do not include the zero terminators at the end
+** of the string.  ^For clarity: the values returned by
+** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
+** bytes in the string, not the number of characters.
+**
+** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
+** even empty strings, are always zero-terminated.  ^The return
+** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
+**
+** ^Strings returned by sqlite3_column_text16() always have the endianness
+** which is native to the platform, regardless of the text encoding set
+** for the database.
+**
+** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
+** [unprotected sqlite3_value] object.  In a multithreaded environment,
+** an unprotected sqlite3_value object may only be used safely with
+** [sqlite3_bind_value()] and [sqlite3_result_value()].
+** If the [unprotected sqlite3_value] object returned by
+** [sqlite3_column_value()] is used in any other way, including calls
+** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
+** or [sqlite3_value_bytes()], the behavior is not threadsafe.
+** Hence, the sqlite3_column_value() interface
+** is normally only useful within the implementation of
+** [application-defined SQL functions] or [virtual tables], not within
+** top-level application code.
+**
+** These routines may attempt to convert the datatype of the result.
+** ^For example, if the internal representation is FLOAT and a text result
+** is requested, [sqlite3_snprintf()] is used internally to perform the
+** conversion automatically.  ^(The following table details the conversions
+** that are applied:
+**
+** <blockquote>
+** <table border="1">
+** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
+**
+** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
+** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
+** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
+** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
+** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
+** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
+** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
+** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
+** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
+** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
+** <tr><td>  TEXT    <td>   BLOB    <td> No change
+** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
+** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
+** <tr><td>  BLOB    <td>   TEXT    <td> [CAST] to TEXT, ensure zero terminator
+** </table>
+** </blockquote>)^
+**
+** Note that when type conversions occur, pointers returned by prior
+** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
+** sqlite3_column_text16() may be invalidated.
+** Type conversions and pointer invalidations might occur
+** in the following cases:
+**
+** <ul>
+** <li> The initial content is a BLOB and sqlite3_column_text() or
+**      sqlite3_column_text16() is called.  A zero-terminator might
+**      need to be added to the string.</li>
+** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
+**      sqlite3_column_text16() is called.  The content must be converted
+**      to UTF-16.</li>
+** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
+**      sqlite3_column_text() is called.  The content must be converted
+**      to UTF-8.</li>
+** </ul>
+**
+** ^Conversions between UTF-16be and UTF-16le are always done in place and do
+** not invalidate a prior pointer, though of course the content of the buffer
+** that the prior pointer references will have been modified.  Other kinds
+** of conversion are done in place when it is possible, but sometimes they
+** are not possible and in those cases prior pointers are invalidated.
+**
+** The safest policy is to invoke these routines
+** in one of the following ways:
+**
+** <ul>
+**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
+**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
+** </ul>
+**
+** In other words, you should call sqlite3_column_text(),
+** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
+** into the desired format, then invoke sqlite3_column_bytes() or
+** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
+** to sqlite3_column_text() or sqlite3_column_blob() with calls to
+** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
+** with calls to sqlite3_column_bytes().
+**
+** ^The pointers returned are valid until a type conversion occurs as
+** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
+** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
+** and BLOBs is freed automatically.  Do not pass the pointers returned
+** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
+** [sqlite3_free()].
+**
+** As long as the input parameters are correct, these routines will only
+** fail if an out-of-memory error occurs during a format conversion.
+** Only the following subset of interfaces are subject to out-of-memory
+** errors:
+**
+** <ul>
+** <li> sqlite3_column_blob()
+** <li> sqlite3_column_text()
+** <li> sqlite3_column_text16()
+** <li> sqlite3_column_bytes()
+** <li> sqlite3_column_bytes16()
+** </ul>
+**
+** If an out-of-memory error occurs, then the return value from these
+** routines is the same as if the column had contained an SQL NULL value.
+** Valid SQL NULL returns can be distinguished from out-of-memory errors
+** by invoking the [sqlite3_errcode()] immediately after the suspect
+** return value is obtained and before any
+** other SQLite interface is called on the same [database connection].
+*/
+SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
+SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
+SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
+SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
+SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
+SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
+
+/*
+** CAPI3REF: Destroy A Prepared Statement Object
+** DESTRUCTOR: sqlite3_stmt
+**
+** ^The sqlite3_finalize() function is called to delete a [prepared statement].
+** ^If the most recent evaluation of the statement encountered no errors
+** or if the statement is never been evaluated, then sqlite3_finalize() returns
+** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
+** sqlite3_finalize(S) returns the appropriate [error code] or
+** [extended error code].
+**
+** ^The sqlite3_finalize(S) routine can be called at any point during
+** the life cycle of [prepared statement] S:
+** before statement S is ever evaluated, after
+** one or more calls to [sqlite3_reset()], or after any call
+** to [sqlite3_step()] regardless of whether or not the statement has
+** completed execution.
+**
+** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
+**
+** The application must finalize every [prepared statement] in order to avoid
+** resource leaks.  It is a grievous error for the application to try to use
+** a prepared statement after it has been finalized.  Any use of a prepared
+** statement after it has been finalized can result in undefined and
+** undesirable behavior such as segfaults and heap corruption.
+*/
+SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Reset A Prepared Statement Object
+** METHOD: sqlite3_stmt
+**
+** The sqlite3_reset() function is called to reset a [prepared statement]
+** object back to its initial state, ready to be re-executed.
+** ^Any SQL statement variables that had values bound to them using
+** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
+** Use [sqlite3_clear_bindings()] to reset the bindings.
+**
+** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
+** back to the beginning of its program.
+**
+** ^The return code from [sqlite3_reset(S)] indicates whether or not
+** the previous evaluation of prepared statement S completed successfully.
+** ^If [sqlite3_step(S)] has never before been called on S or if
+** [sqlite3_step(S)] has not been called since the previous call
+** to [sqlite3_reset(S)], then [sqlite3_reset(S)] will return
+** [SQLITE_OK].
+**
+** ^If the most recent call to [sqlite3_step(S)] for the
+** [prepared statement] S indicated an error, then
+** [sqlite3_reset(S)] returns an appropriate [error code].
+** ^The [sqlite3_reset(S)] interface might also return an [error code]
+** if there were no prior errors but the process of resetting
+** the prepared statement caused a new error. ^For example, if an
+** [INSERT] statement with a [RETURNING] clause is only stepped one time,
+** that one call to [sqlite3_step(S)] might return SQLITE_ROW but
+** the overall statement might still fail and the [sqlite3_reset(S)] call
+** might return SQLITE_BUSY if locking constraints prevent the
+** database change from committing.  Therefore, it is important that
+** applications check the return code from [sqlite3_reset(S)] even if
+** no prior call to [sqlite3_step(S)] indicated a problem.
+**
+** ^The [sqlite3_reset(S)] interface does not change the values
+** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
+*/
+SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
+
+
+/*
+** CAPI3REF: Create Or Redefine SQL Functions
+** KEYWORDS: {function creation routines}
+** METHOD: sqlite3
+**
+** ^These functions (collectively known as "function creation routines")
+** are used to add SQL functions or aggregates or to redefine the behavior
+** of existing SQL functions or aggregates. The only differences between
+** the three "sqlite3_create_function*" routines are the text encoding
+** expected for the second parameter (the name of the function being
+** created) and the presence or absence of a destructor callback for
+** the application data pointer. Function sqlite3_create_window_function()
+** is similar, but allows the user to supply the extra callback functions
+** needed by [aggregate window functions].
+**
+** ^The first parameter is the [database connection] to which the SQL
+** function is to be added.  ^If an application uses more than one database
+** connection then application-defined SQL functions must be added
+** to each database connection separately.
+**
+** ^The second parameter is the name of the SQL function to be created or
+** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
+** representation, exclusive of the zero-terminator.  ^Note that the name
+** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
+** ^Any attempt to create a function with a longer name
+** will result in [SQLITE_MISUSE] being returned.
+**
+** ^The third parameter (nArg)
+** is the number of arguments that the SQL function or
+** aggregate takes. ^If this parameter is -1, then the SQL function or
+** aggregate may take any number of arguments between 0 and the limit
+** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
+** parameter is less than -1 or greater than 127 then the behavior is
+** undefined.
+**
+** ^The fourth parameter, eTextRep, specifies what
+** [SQLITE_UTF8 | text encoding] this SQL function prefers for
+** its parameters.  The application should set this parameter to
+** [SQLITE_UTF16LE] if the function implementation invokes
+** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
+** implementation invokes [sqlite3_value_text16be()] on an input, or
+** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
+** otherwise.  ^The same SQL function may be registered multiple times using
+** different preferred text encodings, with different implementations for
+** each encoding.
+** ^When multiple implementations of the same function are available, SQLite
+** will pick the one that involves the least amount of data conversion.
+**
+** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
+** to signal that the function will always return the same result given
+** the same inputs within a single SQL statement.  Most SQL functions are
+** deterministic.  The built-in [random()] SQL function is an example of a
+** function that is not deterministic.  The SQLite query planner is able to
+** perform additional optimizations on deterministic functions, so use
+** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
+**
+** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
+** flag, which if present prevents the function from being invoked from
+** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
+** index expressions, or the WHERE clause of partial indexes.
+**
+** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
+** all application-defined SQL functions that do not need to be
+** used inside of triggers, view, CHECK constraints, or other elements of
+** the database schema.  This flags is especially recommended for SQL
+** functions that have side effects or reveal internal application state.
+** Without this flag, an attacker might be able to modify the schema of
+** a database file to include invocations of the function with parameters
+** chosen by the attacker, which the application will then execute when
+** the database file is opened and read.
+**
+** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
+** function can gain access to this pointer using [sqlite3_user_data()].)^
+**
+** ^The sixth, seventh and eighth parameters passed to the three
+** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
+** pointers to C-language functions that implement the SQL function or
+** aggregate. ^A scalar SQL function requires an implementation of the xFunc
+** callback only; NULL pointers must be passed as the xStep and xFinal
+** parameters. ^An aggregate SQL function requires an implementation of xStep
+** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
+** SQL function or aggregate, pass NULL pointers for all three function
+** callbacks.
+**
+** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
+** and xInverse) passed to sqlite3_create_window_function are pointers to
+** C-language callbacks that implement the new function. xStep and xFinal
+** must both be non-NULL. xValue and xInverse may either both be NULL, in
+** which case a regular aggregate function is created, or must both be
+** non-NULL, in which case the new function may be used as either an aggregate
+** or aggregate window function. More details regarding the implementation
+** of aggregate window functions are
+** [user-defined window functions|available here].
+**
+** ^(If the final parameter to sqlite3_create_function_v2() or
+** sqlite3_create_window_function() is not NULL, then it is destructor for
+** the application data pointer. The destructor is invoked when the function
+** is deleted, either by being overloaded or when the database connection
+** closes.)^ ^The destructor is also invoked if the call to
+** sqlite3_create_function_v2() fails.  ^When the destructor callback is
+** invoked, it is passed a single argument which is a copy of the application
+** data pointer which was the fifth parameter to sqlite3_create_function_v2().
+**
+** ^It is permitted to register multiple implementations of the same
+** functions with the same name but with either differing numbers of
+** arguments or differing preferred text encodings.  ^SQLite will use
+** the implementation that most closely matches the way in which the
+** SQL function is used.  ^A function implementation with a non-negative
+** nArg parameter is a better match than a function implementation with
+** a negative nArg.  ^A function where the preferred text encoding
+** matches the database encoding is a better
+** match than a function where the encoding is different.
+** ^A function where the encoding difference is between UTF16le and UTF16be
+** is a closer match than a function where the encoding difference is
+** between UTF8 and UTF16.
+**
+** ^Built-in functions may be overloaded by new application-defined functions.
+**
+** ^An application-defined function is permitted to call other
+** SQLite interfaces.  However, such calls must not
+** close the database connection nor finalize or reset the prepared
+** statement in which the function is running.
+*/
+SQLITE_API int sqlite3_create_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+SQLITE_API int sqlite3_create_function16(
+  sqlite3 *db,
+  const void *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*)
+);
+SQLITE_API int sqlite3_create_function_v2(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void(*xDestroy)(void*)
+);
+SQLITE_API int sqlite3_create_window_function(
+  sqlite3 *db,
+  const char *zFunctionName,
+  int nArg,
+  int eTextRep,
+  void *pApp,
+  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+  void (*xFinal)(sqlite3_context*),
+  void (*xValue)(sqlite3_context*),
+  void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
+  void(*xDestroy)(void*)
+);
+
+/*
+** CAPI3REF: Text Encodings
+**
+** These constant define integer codes that represent the various
+** text encodings supported by SQLite.
+*/
+#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
+#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
+#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
+#define SQLITE_UTF16          4    /* Use native byte order */
+#define SQLITE_ANY            5    /* Deprecated */
+#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
+
+/*
+** CAPI3REF: Function Flags
+**
+** These constants may be ORed together with the
+** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
+** to [sqlite3_create_function()], [sqlite3_create_function16()], or
+** [sqlite3_create_function_v2()].
+**
+** <dl>
+** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
+** The SQLITE_DETERMINISTIC flag means that the new function always gives
+** the same output when the input parameters are the same.
+** The [abs|abs() function] is deterministic, for example, but
+** [randomblob|randomblob()] is not.  Functions must
+** be deterministic in order to be used in certain contexts such as
+** with the WHERE clause of [partial indexes] or in [generated columns].
+** SQLite might also optimize deterministic functions by factoring them
+** out of inner loops.
+** </dd>
+**
+** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
+** The SQLITE_DIRECTONLY flag means that the function may only be invoked
+** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
+** schema structures such as [CHECK constraints], [DEFAULT clauses],
+** [expression indexes], [partial indexes], or [generated columns].
+** <p>
+** The SQLITE_DIRECTONLY flag is recommended for any
+** [application-defined SQL function]
+** that has side-effects or that could potentially leak sensitive information.
+** This will prevent attacks in which an application is tricked
+** into using a database file that has had its schema surreptitiously
+** modified to invoke the application-defined function in ways that are
+** harmful.
+** <p>
+** Some people say it is good practice to set SQLITE_DIRECTONLY on all
+** [application-defined SQL functions], regardless of whether or not they
+** are security sensitive, as doing so prevents those functions from being used
+** inside of the database schema, and thus ensures that the database
+** can be inspected and modified using generic tools (such as the [CLI])
+** that do not have access to the application-defined functions.
+** </dd>
+**
+** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
+** The SQLITE_INNOCUOUS flag means that the function is unlikely
+** to cause problems even if misused.  An innocuous function should have
+** no side effects and should not depend on any values other than its
+** input parameters. The [abs|abs() function] is an example of an
+** innocuous function.
+** The [load_extension() SQL function] is not innocuous because of its
+** side effects.
+** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
+** exactly the same.  The [random|random() function] is an example of a
+** function that is innocuous but not deterministic.
+** <p>Some heightened security settings
+** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
+** disable the use of SQL functions inside views and triggers and in
+** schema structures such as [CHECK constraints], [DEFAULT clauses],
+** [expression indexes], [partial indexes], and [generated columns] unless
+** the function is tagged with SQLITE_INNOCUOUS.  Most built-in functions
+** are innocuous.  Developers are advised to avoid using the
+** SQLITE_INNOCUOUS flag for application-defined functions unless the
+** function has been carefully audited and found to be free of potentially
+** security-adverse side-effects and information-leaks.
+** </dd>
+**
+** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
+** The SQLITE_SUBTYPE flag indicates to SQLite that a function might call
+** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
+** This flag instructs SQLite to omit some corner-case optimizations that
+** might disrupt the operation of the [sqlite3_value_subtype()] function,
+** causing it to return zero rather than the correct subtype().
+** All SQL functions that invoke [sqlite3_value_subtype()] should have this
+** property.  If the SQLITE_SUBTYPE property is omitted, then the return
+** value from [sqlite3_value_subtype()] might sometimes be zero even though
+** a non-zero subtype was specified by the function argument expression.
+**
+** [[SQLITE_RESULT_SUBTYPE]] <dt>SQLITE_RESULT_SUBTYPE</dt><dd>
+** The SQLITE_RESULT_SUBTYPE flag indicates to SQLite that a function might call
+** [sqlite3_result_subtype()] to cause a sub-type to be associated with its
+** result.
+** Every function that invokes [sqlite3_result_subtype()] should have this
+** property.  If it does not, then the call to [sqlite3_result_subtype()]
+** might become a no-op if the function is used as term in an
+** [expression index].  On the other hand, SQL functions that never invoke
+** [sqlite3_result_subtype()] should avoid setting this property, as the
+** purpose of this property is to disable certain optimizations that are
+** incompatible with subtypes.
+**
+** [[SQLITE_SELFORDER1]] <dt>SQLITE_SELFORDER1</dt><dd>
+** The SQLITE_SELFORDER1 flag indicates that the function is an aggregate
+** that internally orders the values provided to the first argument.  The
+** ordered-set aggregate SQL notation with a single ORDER BY term can be
+** used to invoke this function.  If the ordered-set aggregate notation is
+** used on a function that lacks this flag, then an error is raised. Note
+** that the ordered-set aggregate syntax is only available if SQLite is
+** built using the -DSQLITE_ENABLE_ORDERED_SET_AGGREGATES compile-time option.
+** </dd>
+** </dl>
+*/
+#define SQLITE_DETERMINISTIC    0x000000800
+#define SQLITE_DIRECTONLY       0x000080000
+#define SQLITE_SUBTYPE          0x000100000
+#define SQLITE_INNOCUOUS        0x000200000
+#define SQLITE_RESULT_SUBTYPE   0x001000000
+#define SQLITE_SELFORDER1       0x002000000
+
+/*
+** CAPI3REF: Deprecated Functions
+** DEPRECATED
+**
+** These functions are [deprecated].  In order to maintain
+** backwards compatibility with older code, these functions continue
+** to be supported.  However, new applications should avoid
+** the use of these functions.  To encourage programmers to avoid
+** these functions, we will not explain what they do.
+*/
+#ifndef SQLITE_OMIT_DEPRECATED
+SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
+SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
+SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
+                      void*,sqlite3_int64);
+#endif
+
+/*
+** CAPI3REF: Obtaining SQL Values
+** METHOD: sqlite3_value
+**
+** <b>Summary:</b>
+** <blockquote><table border=0 cellpadding=0 cellspacing=0>
+** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value
+** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value
+** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value
+** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value
+** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value
+** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value
+** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in
+** the native byteorder
+** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value
+** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value
+** <tr><td> <td> <td> 
+** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB
+** or a UTF-8 TEXT in bytes
+** <tr><td><b>sqlite3_value_bytes16  </b>
+** <td>→  <td>Size of UTF-16
+** TEXT in bytes
+** <tr><td><b>sqlite3_value_type</b><td>→<td>Default
+** datatype of the value
+** <tr><td><b>sqlite3_value_numeric_type  </b>
+** <td>→  <td>Best numeric datatype of the value
+** <tr><td><b>sqlite3_value_nochange  </b>
+** <td>→  <td>True if the column is unchanged in an UPDATE
+** against a virtual table.
+** <tr><td><b>sqlite3_value_frombind  </b>
+** <td>→  <td>True if value originated from a [bound parameter]
+** </table></blockquote>
+**
+** <b>Details:</b>
+**
+** These routines extract type, size, and content information from
+** [protected sqlite3_value] objects.  Protected sqlite3_value objects
+** are used to pass parameter information into the functions that
+** implement [application-defined SQL functions] and [virtual tables].
+**
+** These routines work only with [protected sqlite3_value] objects.
+** Any attempt to use these routines on an [unprotected sqlite3_value]
+** is not threadsafe.
+**
+** ^These routines work just like the corresponding [column access functions]
+** except that these routines take a single [protected sqlite3_value] object
+** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
+**
+** ^The sqlite3_value_text16() interface extracts a UTF-16 string
+** in the native byte-order of the host machine.  ^The
+** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
+** extract UTF-16 strings as big-endian and little-endian respectively.
+**
+** ^If [sqlite3_value] object V was initialized
+** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
+** and if X and Y are strings that compare equal according to strcmp(X,Y),
+** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
+** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
+** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
+**
+** ^(The sqlite3_value_type(V) interface returns the
+** [SQLITE_INTEGER | datatype code] for the initial datatype of the
+** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
+** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
+** Other interfaces might change the datatype for an sqlite3_value object.
+** For example, if the datatype is initially SQLITE_INTEGER and
+** sqlite3_value_text(V) is called to extract a text value for that
+** integer, then subsequent calls to sqlite3_value_type(V) might return
+** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
+** occurs is undefined and may change from one release of SQLite to the next.
+**
+** ^(The sqlite3_value_numeric_type() interface attempts to apply
+** numeric affinity to the value.  This means that an attempt is
+** made to convert the value to an integer or floating point.  If
+** such a conversion is possible without loss of information (in other
+** words, if the value is a string that looks like a number)
+** then the conversion is performed.  Otherwise no conversion occurs.
+** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
+**
+** ^Within the [xUpdate] method of a [virtual table], the
+** sqlite3_value_nochange(X) interface returns true if and only if
+** the column corresponding to X is unchanged by the UPDATE operation
+** that the xUpdate method call was invoked to implement and if
+** and the prior [xColumn] method call that was invoked to extracted
+** the value for that column returned without setting a result (probably
+** because it queried [sqlite3_vtab_nochange()] and found that the column
+** was unchanging).  ^Within an [xUpdate] method, any value for which
+** sqlite3_value_nochange(X) is true will in all other respects appear
+** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
+** than within an [xUpdate] method call for an UPDATE statement, then
+** the return value is arbitrary and meaningless.
+**
+** ^The sqlite3_value_frombind(X) interface returns non-zero if the
+** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
+** interfaces.  ^If X comes from an SQL literal value, or a table column,
+** or an expression, then sqlite3_value_frombind(X) returns zero.
+**
+** Please pay particular attention to the fact that the pointer returned
+** from [sqlite3_value_blob()], [sqlite3_value_text()], or
+** [sqlite3_value_text16()] can be invalidated by a subsequent call to
+** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
+** or [sqlite3_value_text16()].
+**
+** These routines must be called from the same thread as
+** the SQL function that supplied the [sqlite3_value*] parameters.
+**
+** As long as the input parameter is correct, these routines can only
+** fail if an out-of-memory error occurs during a format conversion.
+** Only the following subset of interfaces are subject to out-of-memory
+** errors:
+**
+** <ul>
+** <li> sqlite3_value_blob()
+** <li> sqlite3_value_text()
+** <li> sqlite3_value_text16()
+** <li> sqlite3_value_text16le()
+** <li> sqlite3_value_text16be()
+** <li> sqlite3_value_bytes()
+** <li> sqlite3_value_bytes16()
+** </ul>
+**
+** If an out-of-memory error occurs, then the return value from these
+** routines is the same as if the column had contained an SQL NULL value.
+** Valid SQL NULL returns can be distinguished from out-of-memory errors
+** by invoking the [sqlite3_errcode()] immediately after the suspect
+** return value is obtained and before any
+** other SQLite interface is called on the same [database connection].
+*/
+SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
+SQLITE_API double sqlite3_value_double(sqlite3_value*);
+SQLITE_API int sqlite3_value_int(sqlite3_value*);
+SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
+SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
+SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
+SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
+SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
+SQLITE_API int sqlite3_value_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
+SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
+SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
+
+/*
+** CAPI3REF: Report the internal text encoding state of an sqlite3_value object
+** METHOD: sqlite3_value
+**
+** ^(The sqlite3_value_encoding(X) interface returns one of [SQLITE_UTF8],
+** [SQLITE_UTF16BE], or [SQLITE_UTF16LE] according to the current text encoding
+** of the value X, assuming that X has type TEXT.)^  If sqlite3_value_type(X)
+** returns something other than SQLITE_TEXT, then the return value from
+** sqlite3_value_encoding(X) is meaningless.  ^Calls to
+** [sqlite3_value_text(X)], [sqlite3_value_text16(X)], [sqlite3_value_text16be(X)],
+** [sqlite3_value_text16le(X)], [sqlite3_value_bytes(X)], or
+** [sqlite3_value_bytes16(X)] might change the encoding of the value X and
+** thus change the return from subsequent calls to sqlite3_value_encoding(X).
+**
+** This routine is intended for used by applications that test and validate
+** the SQLite implementation.  This routine is inquiring about the opaque
+** internal state of an [sqlite3_value] object.  Ordinary applications should
+** not need to know what the internal state of an sqlite3_value object is and
+** hence should not need to use this interface.
+*/
+SQLITE_API int sqlite3_value_encoding(sqlite3_value*);
+
+/*
+** CAPI3REF: Finding The Subtype Of SQL Values
+** METHOD: sqlite3_value
+**
+** The sqlite3_value_subtype(V) function returns the subtype for
+** an [application-defined SQL function] argument V.  The subtype
+** information can be used to pass a limited amount of context from
+** one SQL function to another.  Use the [sqlite3_result_subtype()]
+** routine to set the subtype for the return value of an SQL function.
+**
+** Every [application-defined SQL function] that invokes this interface
+** should include the [SQLITE_SUBTYPE] property in the text
+** encoding argument when the function is [sqlite3_create_function|registered].
+** If the [SQLITE_SUBTYPE] property is omitted, then sqlite3_value_subtype()
+** might return zero instead of the upstream subtype in some corner cases.
+*/
+SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
+
+/*
+** CAPI3REF: Copy And Free SQL Values
+** METHOD: sqlite3_value
+**
+** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
+** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
+** is a [protected sqlite3_value] object even if the input is not.
+** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
+** memory allocation fails. ^If V is a [pointer value], then the result
+** of sqlite3_value_dup(V) is a NULL value.
+**
+** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
+** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
+** then sqlite3_value_free(V) is a harmless no-op.
+*/
+SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
+SQLITE_API void sqlite3_value_free(sqlite3_value*);
+
+/*
+** CAPI3REF: Obtain Aggregate Function Context
+** METHOD: sqlite3_context
+**
+** Implementations of aggregate SQL functions use this
+** routine to allocate memory for storing their state.
+**
+** ^The first time the sqlite3_aggregate_context(C,N) routine is called
+** for a particular aggregate function, SQLite allocates
+** N bytes of memory, zeroes out that memory, and returns a pointer
+** to the new memory. ^On second and subsequent calls to
+** sqlite3_aggregate_context() for the same aggregate function instance,
+** the same buffer is returned.  Sqlite3_aggregate_context() is normally
+** called once for each invocation of the xStep callback and then one
+** last time when the xFinal callback is invoked.  ^(When no rows match
+** an aggregate query, the xStep() callback of the aggregate function
+** implementation is never called and xFinal() is called exactly once.
+** In those cases, sqlite3_aggregate_context() might be called for the
+** first time from within xFinal().)^
+**
+** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
+** when first called if N is less than or equal to zero or if a memory
+** allocation error occurs.
+**
+** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
+** determined by the N parameter on first successful call.  Changing the
+** value of N in any subsequent call to sqlite3_aggregate_context() within
+** the same aggregate function instance will not resize the memory
+** allocation.)^  Within the xFinal callback, it is customary to set
+** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
+** pointless memory allocations occur.
+**
+** ^SQLite automatically frees the memory allocated by
+** sqlite3_aggregate_context() when the aggregate query concludes.
+**
+** The first parameter must be a copy of the
+** [sqlite3_context | SQL function context] that is the first parameter
+** to the xStep or xFinal callback routine that implements the aggregate
+** function.
+**
+** This routine must be called from the same thread in which
+** the aggregate SQL function is running.
+*/
+SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
+
+/*
+** CAPI3REF: User Data For Functions
+** METHOD: sqlite3_context
+**
+** ^The sqlite3_user_data() interface returns a copy of
+** the pointer that was the pUserData parameter (the 5th parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+**
+** This routine must be called from the same thread in which
+** the application-defined function is running.
+*/
+SQLITE_API void *sqlite3_user_data(sqlite3_context*);
+
+/*
+** CAPI3REF: Database Connection For Functions
+** METHOD: sqlite3_context
+**
+** ^The sqlite3_context_db_handle() interface returns a copy of
+** the pointer to the [database connection] (the 1st parameter)
+** of the [sqlite3_create_function()]
+** and [sqlite3_create_function16()] routines that originally
+** registered the application defined function.
+*/
+SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
+
+/*
+** CAPI3REF: Function Auxiliary Data
+** METHOD: sqlite3_context
+**
+** These functions may be used by (non-aggregate) SQL functions to
+** associate auxiliary data with argument values. If the same argument
+** value is passed to multiple invocations of the same SQL function during
+** query execution, under some circumstances the associated auxiliary data
+** might be preserved.  An example of where this might be useful is in a
+** regular-expression matching function. The compiled version of the regular
+** expression can be stored as auxiliary data associated with the pattern string.
+** Then as long as the pattern string remains the same,
+** the compiled regular expression can be reused on multiple
+** invocations of the same function.
+**
+** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the auxiliary data
+** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
+** value to the application-defined function.  ^N is zero for the left-most
+** function argument.  ^If there is no auxiliary data
+** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
+** returns a NULL pointer.
+**
+** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as auxiliary data for the
+** N-th argument of the application-defined function.  ^Subsequent
+** calls to sqlite3_get_auxdata(C,N) return P from the most recent
+** sqlite3_set_auxdata(C,N,P,X) call if the auxiliary data is still valid or
+** NULL if the auxiliary data has been discarded.
+** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
+** SQLite will invoke the destructor function X with parameter P exactly
+** once, when the auxiliary data is discarded.
+** SQLite is free to discard the auxiliary data at any time, including: <ul>
+** <li> ^(when the corresponding function parameter changes)^, or
+** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
+**      SQL statement)^, or
+** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
+**       parameter)^, or
+** <li> ^(during the original sqlite3_set_auxdata() call when a memory
+**      allocation error occurs.)^
+** <li> ^(during the original sqlite3_set_auxdata() call if the function
+**      is evaluated during query planning instead of during query execution,
+**      as sometimes happens with [SQLITE_ENABLE_STAT4].)^ </ul>
+**
+** Note the last two bullets in particular.  The destructor X in
+** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
+** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
+** should be called near the end of the function implementation and the
+** function implementation should not make any use of P after
+** sqlite3_set_auxdata() has been called.  Furthermore, a call to
+** sqlite3_get_auxdata() that occurs immediately after a corresponding call
+** to sqlite3_set_auxdata() might still return NULL if an out-of-memory
+** condition occurred during the sqlite3_set_auxdata() call or if the
+** function is being evaluated during query planning rather than during
+** query execution.
+**
+** ^(In practice, auxiliary data is preserved between function calls for
+** function parameters that are compile-time constants, including literal
+** values and [parameters] and expressions composed from the same.)^
+**
+** The value of the N parameter to these interfaces should be non-negative.
+** Future enhancements may make use of negative N values to define new
+** kinds of function caching behavior.
+**
+** These routines must be called from the same thread in which
+** the SQL function is running.
+**
+** See also: [sqlite3_get_clientdata()] and [sqlite3_set_clientdata()].
+*/
+SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
+SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
+
+/*
+** CAPI3REF: Database Connection Client Data
+** METHOD: sqlite3
+**
+** These functions are used to associate one or more named pointers
+** with a [database connection].
+** A call to sqlite3_set_clientdata(D,N,P,X) causes the pointer P
+** to be attached to [database connection] D using name N.  Subsequent
+** calls to sqlite3_get_clientdata(D,N) will return a copy of pointer P
+** or a NULL pointer if there were no prior calls to
+** sqlite3_set_clientdata() with the same values of D and N.
+** Names are compared using strcmp() and are thus case sensitive.
+**
+** If P and X are both non-NULL, then the destructor X is invoked with
+** argument P on the first of the following occurrences:
+** <ul>
+** <li> An out-of-memory error occurs during the call to
+**      sqlite3_set_clientdata() which attempts to register pointer P.
+** <li> A subsequent call to sqlite3_set_clientdata(D,N,P,X) is made
+**      with the same D and N parameters.
+** <li> The database connection closes.  SQLite does not make any guarantees
+**      about the order in which destructors are called, only that all
+**      destructors will be called exactly once at some point during the
+**      database connection closing process.
+** </ul>
+**
+** SQLite does not do anything with client data other than invoke
+** destructors on the client data at the appropriate time.  The intended
+** use for client data is to provide a mechanism for wrapper libraries
+** to store additional information about an SQLite database connection.
+**
+** There is no limit (other than available memory) on the number of different
+** client data pointers (with different names) that can be attached to a
+** single database connection.  However, the implementation is optimized
+** for the case of having only one or two different client data names.
+** Applications and wrapper libraries are discouraged from using more than
+** one client data name each.
+**
+** There is no way to enumerate the client data pointers
+** associated with a database connection.  The N parameter can be thought
+** of as a secret key such that only code that knows the secret key is able
+** to access the associated data.
+**
+** Security Warning:  These interfaces should not be exposed in scripting
+** languages or in other circumstances where it might be possible for an
+** an attacker to invoke them.  Any agent that can invoke these interfaces
+** can probably also take control of the process.
+**
+** Database connection client data is only available for SQLite
+** version 3.44.0 ([dateof:3.44.0]) and later.
+**
+** See also: [sqlite3_set_auxdata()] and [sqlite3_get_auxdata()].
+*/
+SQLITE_API void *sqlite3_get_clientdata(sqlite3*,const char*);
+SQLITE_API int sqlite3_set_clientdata(sqlite3*, const char*, void*, void(*)(void*));
+
+/*
+** CAPI3REF: Constants Defining Special Destructor Behavior
+**
+** These are special values for the destructor that is passed in as the
+** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
+** argument is SQLITE_STATIC, it means that the content pointer is constant
+** and will never change.  It does not need to be destroyed.  ^The
+** SQLITE_TRANSIENT value means that the content will likely change in
+** the near future and that SQLite should make its own private copy of
+** the content before returning.
+**
+** The typedef is necessary to work around problems in certain
+** C++ compilers.
+*/
+typedef void (*sqlite3_destructor_type)(void*);
+#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
+#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
+
+/*
+** CAPI3REF: Setting The Result Of An SQL Function
+** METHOD: sqlite3_context
+**
+** These routines are used by the xFunc or xFinal callbacks that
+** implement SQL functions and aggregates.  See
+** [sqlite3_create_function()] and [sqlite3_create_function16()]
+** for additional information.
+**
+** These functions work very much like the [parameter binding] family of
+** functions used to bind values to host parameters in prepared statements.
+** Refer to the [SQL parameter] documentation for additional information.
+**
+** ^The sqlite3_result_blob() interface sets the result from
+** an application-defined function to be the BLOB whose content is pointed
+** to by the second parameter and which is N bytes long where N is the
+** third parameter.
+**
+** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
+** interfaces set the result of the application-defined function to be
+** a BLOB containing all zero bytes and N bytes in size.
+**
+** ^The sqlite3_result_double() interface sets the result from
+** an application-defined function to be a floating point value specified
+** by its 2nd argument.
+**
+** ^The sqlite3_result_error() and sqlite3_result_error16() functions
+** cause the implemented SQL function to throw an exception.
+** ^SQLite uses the string pointed to by the
+** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
+** as the text of an error message.  ^SQLite interprets the error
+** message string from sqlite3_result_error() as UTF-8. ^SQLite
+** interprets the string from sqlite3_result_error16() as UTF-16 using
+** the same [byte-order determination rules] as [sqlite3_bind_text16()].
+** ^If the third parameter to sqlite3_result_error()
+** or sqlite3_result_error16() is negative then SQLite takes as the error
+** message all text up through the first zero character.
+** ^If the third parameter to sqlite3_result_error() or
+** sqlite3_result_error16() is non-negative then SQLite takes that many
+** bytes (not characters) from the 2nd parameter as the error message.
+** ^The sqlite3_result_error() and sqlite3_result_error16()
+** routines make a private copy of the error message text before
+** they return.  Hence, the calling function can deallocate or
+** modify the text after they return without harm.
+** ^The sqlite3_result_error_code() function changes the error code
+** returned by SQLite as a result of an error in a function.  ^By default,
+** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
+** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
+**
+** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
+** error indicating that a string or BLOB is too long to represent.
+**
+** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
+** error indicating that a memory allocation failed.
+**
+** ^The sqlite3_result_int() interface sets the return value
+** of the application-defined function to be the 32-bit signed integer
+** value given in the 2nd argument.
+** ^The sqlite3_result_int64() interface sets the return value
+** of the application-defined function to be the 64-bit signed integer
+** value given in the 2nd argument.
+**
+** ^The sqlite3_result_null() interface sets the return value
+** of the application-defined function to be NULL.
+**
+** ^The sqlite3_result_text(), sqlite3_result_text16(),
+** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
+** set the return value of the application-defined function to be
+** a text string which is represented as UTF-8, UTF-16 native byte order,
+** UTF-16 little endian, or UTF-16 big endian, respectively.
+** ^The sqlite3_result_text64() interface sets the return value of an
+** application-defined function to be a text string in an encoding
+** specified by the fifth (and last) parameter, which must be one
+** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
+** ^SQLite takes the text result from the application from
+** the 2nd parameter of the sqlite3_result_text* interfaces.
+** ^If the 3rd parameter to any of the sqlite3_result_text* interfaces
+** other than sqlite3_result_text64() is negative, then SQLite computes
+** the string length itself by searching the 2nd parameter for the first
+** zero character.
+** ^If the 3rd parameter to the sqlite3_result_text* interfaces
+** is non-negative, then as many bytes (not characters) of the text
+** pointed to by the 2nd parameter are taken as the application-defined
+** function result.  If the 3rd parameter is non-negative, then it
+** must be the byte offset into the string where the NUL terminator would
+** appear if the string where NUL terminated.  If any NUL characters occur
+** in the string at a byte offset that is less than the value of the 3rd
+** parameter, then the resulting string will contain embedded NULs and the
+** result of expressions operating on strings with embedded NULs is undefined.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
+** function as the destructor on the text or BLOB result when it has
+** finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
+** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
+** assumes that the text or BLOB result is in constant space and does not
+** copy the content of the parameter nor call a destructor on the content
+** when it has finished using that result.
+** ^If the 4th parameter to the sqlite3_result_text* interfaces
+** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
+** then SQLite makes a copy of the result into space obtained
+** from [sqlite3_malloc()] before it returns.
+**
+** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
+** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
+** when the encoding is not UTF8, if the input UTF16 begins with a
+** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
+** string and the rest of the string is interpreted according to the
+** byte-order specified by the BOM.  ^The byte-order specified by
+** the BOM at the beginning of the text overrides the byte-order
+** specified by the interface procedure.  ^So, for example, if
+** sqlite3_result_text16le() is invoked with text that begins
+** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
+** first two bytes of input are skipped and the remaining input
+** is interpreted as UTF16BE text.
+**
+** ^For UTF16 input text to the sqlite3_result_text16(),
+** sqlite3_result_text16be(), sqlite3_result_text16le(), and
+** sqlite3_result_text64() routines, if the text contains invalid
+** UTF16 characters, the invalid characters might be converted
+** into the unicode replacement character, U+FFFD.
+**
+** ^The sqlite3_result_value() interface sets the result of
+** the application-defined function to be a copy of the
+** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
+** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
+** so that the [sqlite3_value] specified in the parameter may change or
+** be deallocated after sqlite3_result_value() returns without harm.
+** ^A [protected sqlite3_value] object may always be used where an
+** [unprotected sqlite3_value] object is required, so either
+** kind of [sqlite3_value] object can be used with this interface.
+**
+** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
+** SQL NULL value, just like [sqlite3_result_null(C)], except that it
+** also associates the host-language pointer P or type T with that
+** NULL value such that the pointer can be retrieved within an
+** [application-defined SQL function] using [sqlite3_value_pointer()].
+** ^If the D parameter is not NULL, then it is a pointer to a destructor
+** for the P parameter.  ^SQLite invokes D with P as its only argument
+** when SQLite is finished with P.  The T parameter should be a static
+** string and preferably a string literal. The sqlite3_result_pointer()
+** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
+**
+** If these routines are called from within the different thread
+** than the one containing the application-defined function that received
+** the [sqlite3_context] pointer, the results are undefined.
+*/
+SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
+                           sqlite3_uint64,void(*)(void*));
+SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
+SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
+SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
+SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
+SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
+SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
+SQLITE_API void sqlite3_result_null(sqlite3_context*);
+SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
+                           void(*)(void*), unsigned char encoding);
+SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
+SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
+SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
+SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
+SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
+SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
+
+
+/*
+** CAPI3REF: Setting The Subtype Of An SQL Function
+** METHOD: sqlite3_context
+**
+** The sqlite3_result_subtype(C,T) function causes the subtype of
+** the result from the [application-defined SQL function] with
+** [sqlite3_context] C to be the value T.  Only the lower 8 bits
+** of the subtype T are preserved in current versions of SQLite;
+** higher order bits are discarded.
+** The number of subtype bytes preserved by SQLite might increase
+** in future releases of SQLite.
+**
+** Every [application-defined SQL function] that invokes this interface
+** should include the [SQLITE_RESULT_SUBTYPE] property in its
+** text encoding argument when the SQL function is
+** [sqlite3_create_function|registered].  If the [SQLITE_RESULT_SUBTYPE]
+** property is omitted from the function that invokes sqlite3_result_subtype(),
+** then in some cases the sqlite3_result_subtype() might fail to set
+** the result subtype.
+**
+** If SQLite is compiled with -DSQLITE_STRICT_SUBTYPE=1, then any
+** SQL function that invokes the sqlite3_result_subtype() interface
+** and that does not have the SQLITE_RESULT_SUBTYPE property will raise
+** an error.  Future versions of SQLite might enable -DSQLITE_STRICT_SUBTYPE=1
+** by default.
+*/
+SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
+
+/*
+** CAPI3REF: Define New Collating Sequences
+** METHOD: sqlite3
+**
+** ^These functions add, remove, or modify a [collation] associated
+** with the [database connection] specified as the first argument.
+**
+** ^The name of the collation is a UTF-8 string
+** for sqlite3_create_collation() and sqlite3_create_collation_v2()
+** and a UTF-16 string in native byte order for sqlite3_create_collation16().
+** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
+** considered to be the same name.
+**
+** ^(The third argument (eTextRep) must be one of the constants:
+** <ul>
+** <li> [SQLITE_UTF8],
+** <li> [SQLITE_UTF16LE],
+** <li> [SQLITE_UTF16BE],
+** <li> [SQLITE_UTF16], or
+** <li> [SQLITE_UTF16_ALIGNED].
+** </ul>)^
+** ^The eTextRep argument determines the encoding of strings passed
+** to the collating function callback, xCompare.
+** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
+** force strings to be UTF16 with native byte order.
+** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
+** on an even byte address.
+**
+** ^The fourth argument, pArg, is an application data pointer that is passed
+** through as the first argument to the collating function callback.
+**
+** ^The fifth argument, xCompare, is a pointer to the collating function.
+** ^Multiple collating functions can be registered using the same name but
+** with different eTextRep parameters and SQLite will use whichever
+** function requires the least amount of data transformation.
+** ^If the xCompare argument is NULL then the collating function is
+** deleted.  ^When all collating functions having the same name are deleted,
+** that collation is no longer usable.
+**
+** ^The collating function callback is invoked with a copy of the pArg
+** application data pointer and with two strings in the encoding specified
+** by the eTextRep argument.  The two integer parameters to the collating
+** function callback are the length of the two strings, in bytes. The collating
+** function must return an integer that is negative, zero, or positive
+** if the first string is less than, equal to, or greater than the second,
+** respectively.  A collating function must always return the same answer
+** given the same inputs.  If two or more collating functions are registered
+** to the same collation name (using different eTextRep values) then all
+** must give an equivalent answer when invoked with equivalent strings.
+** The collating function must obey the following properties for all
+** strings A, B, and C:
+**
+** <ol>
+** <li> If A==B then B==A.
+** <li> If A==B and B==C then A==C.
+** <li> If A<B THEN B>A.
+** <li> If A<B and B<C then A<C.
+** </ol>
+**
+** If a collating function fails any of the above constraints and that
+** collating function is registered and used, then the behavior of SQLite
+** is undefined.
+**
+** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
+** with the addition that the xDestroy callback is invoked on pArg when
+** the collating function is deleted.
+** ^Collating functions are deleted when they are overridden by later
+** calls to the collation creation functions or when the
+** [database connection] is closed using [sqlite3_close()].
+**
+** ^The xDestroy callback is <u>not</u> called if the
+** sqlite3_create_collation_v2() function fails.  Applications that invoke
+** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
+** check the return code and dispose of the application data pointer
+** themselves rather than expecting SQLite to deal with it for them.
+** This is different from every other SQLite interface.  The inconsistency
+** is unfortunate but cannot be changed without breaking backwards
+** compatibility.
+**
+** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
+*/
+SQLITE_API int sqlite3_create_collation(
+  sqlite3*,
+  const char *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+SQLITE_API int sqlite3_create_collation_v2(
+  sqlite3*,
+  const char *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*),
+  void(*xDestroy)(void*)
+);
+SQLITE_API int sqlite3_create_collation16(
+  sqlite3*,
+  const void *zName,
+  int eTextRep,
+  void *pArg,
+  int(*xCompare)(void*,int,const void*,int,const void*)
+);
+
+/*
+** CAPI3REF: Collation Needed Callbacks
+** METHOD: sqlite3
+**
+** ^To avoid having to register all collation sequences before a database
+** can be used, a single callback function may be registered with the
+** [database connection] to be invoked whenever an undefined collation
+** sequence is required.
+**
+** ^If the function is registered using the sqlite3_collation_needed() API,
+** then it is passed the names of undefined collation sequences as strings
+** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
+** the names are passed as UTF-16 in machine native byte order.
+** ^A call to either function replaces the existing collation-needed callback.
+**
+** ^(When the callback is invoked, the first argument passed is a copy
+** of the second argument to sqlite3_collation_needed() or
+** sqlite3_collation_needed16().  The second argument is the database
+** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
+** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
+** sequence function required.  The fourth parameter is the name of the
+** required collation sequence.)^
+**
+** The callback function should register the desired collation using
+** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
+** [sqlite3_create_collation_v2()].
+*/
+SQLITE_API int sqlite3_collation_needed(
+  sqlite3*,
+  void*,
+  void(*)(void*,sqlite3*,int eTextRep,const char*)
+);
+SQLITE_API int sqlite3_collation_needed16(
+  sqlite3*,
+  void*,
+  void(*)(void*,sqlite3*,int eTextRep,const void*)
+);
+
+#ifdef SQLITE_ENABLE_CEROD
+/*
+** Specify the activation key for a CEROD database.  Unless
+** activated, none of the CEROD routines will work.
+*/
+SQLITE_API void sqlite3_activate_cerod(
+  const char *zPassPhrase        /* Activation phrase */
+);
+#endif
+
+/*
+** CAPI3REF: Suspend Execution For A Short Time
+**
+** The sqlite3_sleep() function causes the current thread to suspend execution
+** for at least a number of milliseconds specified in its parameter.
+**
+** If the operating system does not support sleep requests with
+** millisecond time resolution, then the time will be rounded up to
+** the nearest second. The number of milliseconds of sleep actually
+** requested from the operating system is returned.
+**
+** ^SQLite implements this interface by calling the xSleep()
+** method of the default [sqlite3_vfs] object.  If the xSleep() method
+** of the default VFS is not implemented correctly, or not implemented at
+** all, then the behavior of sqlite3_sleep() may deviate from the description
+** in the previous paragraphs.
+**
+** If a negative argument is passed to sqlite3_sleep() the results vary by
+** VFS and operating system.  Some system treat a negative argument as an
+** instruction to sleep forever.  Others understand it to mean do not sleep
+** at all. ^In SQLite version 3.42.0 and later, a negative
+** argument passed into sqlite3_sleep() is changed to zero before it is relayed
+** down into the xSleep method of the VFS.
+*/
+SQLITE_API int sqlite3_sleep(int);
+
+/*
+** CAPI3REF: Name Of The Folder Holding Temporary Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all temporary files
+** created by SQLite when using a built-in [sqlite3_vfs | VFS]
+** will be placed in that directory.)^  ^If this variable
+** is a NULL pointer, then SQLite performs a search for an appropriate
+** temporary file directory.
+**
+** Applications are strongly discouraged from using this global variable.
+** It is required to set a temporary folder on Windows Runtime (WinRT).
+** But for all other platforms, it is highly recommended that applications
+** neither read nor write this variable.  This global variable is a relic
+** that exists for backwards compatibility of legacy applications and should
+** be avoided in new projects.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [temp_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [temp_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [temp_store_directory pragma] should be avoided.
+** Except when requested by the [temp_store_directory pragma], SQLite
+** does not free the memory that sqlite3_temp_directory points to.  If
+** the application wants that memory to be freed, it must do
+** so itself, taking care to only do so after all [database connection]
+** objects have been destroyed.
+**
+** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
+** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
+** features that require the use of temporary files may fail.  Here is an
+** example of how to do this using C++ with the Windows Runtime:
+**
+** <blockquote><pre>
+** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
+**       TemporaryFolder->Path->Data();
+** char zPathBuf[MAX_PATH + 1];
+** memset(zPathBuf, 0, sizeof(zPathBuf));
+** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
+**       NULL, NULL);
+** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
+** </pre></blockquote>
+*/
+SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
+
+/*
+** CAPI3REF: Name Of The Folder Holding Database Files
+**
+** ^(If this global variable is made to point to a string which is
+** the name of a folder (a.k.a. directory), then all database files
+** specified with a relative pathname and created or accessed by
+** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
+** to be relative to that directory.)^ ^If this variable is a NULL
+** pointer, then SQLite assumes that all database files specified
+** with a relative pathname are relative to the current directory
+** for the process.  Only the windows VFS makes use of this global
+** variable; it is ignored by the unix VFS.
+**
+** Changing the value of this variable while a database connection is
+** open can result in a corrupt database.
+**
+** It is not safe to read or modify this variable in more than one
+** thread at a time.  It is not safe to read or modify this variable
+** if a [database connection] is being used at the same time in a separate
+** thread.
+** It is intended that this variable be set once
+** as part of process initialization and before any SQLite interface
+** routines have been called and that this variable remain unchanged
+** thereafter.
+**
+** ^The [data_store_directory pragma] may modify this variable and cause
+** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
+** the [data_store_directory pragma] always assumes that any string
+** that this variable points to is held in memory obtained from
+** [sqlite3_malloc] and the pragma may attempt to free that memory
+** using [sqlite3_free].
+** Hence, if this variable is modified directly, either it should be
+** made NULL or made to point to memory obtained from [sqlite3_malloc]
+** or else the use of the [data_store_directory pragma] should be avoided.
+*/
+SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
+
+/*
+** CAPI3REF: Win32 Specific Interface
+**
+** These interfaces are available only on Windows.  The
+** [sqlite3_win32_set_directory] interface is used to set the value associated
+** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
+** zValue, depending on the value of the type parameter.  The zValue parameter
+** should be NULL to cause the previous value to be freed via [sqlite3_free];
+** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
+** prior to being used.  The [sqlite3_win32_set_directory] interface returns
+** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
+** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
+** [sqlite3_data_directory] variable is intended to act as a replacement for
+** the current directory on the sub-platforms of Win32 where that concept is
+** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
+** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
+** sqlite3_win32_set_directory interface except the string parameter must be
+** UTF-8 or UTF-16, respectively.
+*/
+SQLITE_API int sqlite3_win32_set_directory(
+  unsigned long type, /* Identifier for directory being set or reset */
+  void *zValue        /* New value for directory being set or reset */
+);
+SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
+SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
+
+/*
+** CAPI3REF: Win32 Directory Types
+**
+** These macros are only available on Windows.  They define the allowed values
+** for the type argument to the [sqlite3_win32_set_directory] interface.
+*/
+#define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
+#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
+
+/*
+** CAPI3REF: Test For Auto-Commit Mode
+** KEYWORDS: {autocommit mode}
+** METHOD: sqlite3
+**
+** ^The sqlite3_get_autocommit() interface returns non-zero or
+** zero if the given database connection is or is not in autocommit mode,
+** respectively.  ^Autocommit mode is on by default.
+** ^Autocommit mode is disabled by a [BEGIN] statement.
+** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
+**
+** If certain kinds of errors occur on a statement within a multi-statement
+** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
+** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
+** transaction might be rolled back automatically.  The only way to
+** find out whether SQLite automatically rolled back the transaction after
+** an error is to use this function.
+**
+** If another thread changes the autocommit status of the database
+** connection while this routine is running, then the return value
+** is undefined.
+*/
+SQLITE_API int sqlite3_get_autocommit(sqlite3*);
+
+/*
+** CAPI3REF: Find The Database Handle Of A Prepared Statement
+** METHOD: sqlite3_stmt
+**
+** ^The sqlite3_db_handle interface returns the [database connection] handle
+** to which a [prepared statement] belongs.  ^The [database connection]
+** returned by sqlite3_db_handle is the same [database connection]
+** that was the first argument
+** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
+** create the statement in the first place.
+*/
+SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Return The Schema Name For A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
+** for the N-th database on database connection D, or a NULL pointer of N is
+** out of range.  An N value of 0 means the main database file.  An N of 1 is
+** the "temp" schema.  Larger values of N correspond to various ATTACH-ed
+** databases.
+**
+** Space to hold the string that is returned by sqlite3_db_name() is managed
+** by SQLite itself.  The string might be deallocated by any operation that
+** changes the schema, including [ATTACH] or [DETACH] or calls to
+** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
+** occur on a different thread.  Applications that need to
+** remember the string long-term should make their own copy.  Applications that
+** are accessing the same database connection simultaneously on multiple
+** threads should mutex-protect calls to this API and should make their own
+** private copy of the result prior to releasing the mutex.
+*/
+SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Return The Filename For A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
+** associated with database N of connection D.
+** ^If there is no attached database N on the database
+** connection D, or if database N is a temporary or in-memory database, then
+** this function will return either a NULL pointer or an empty string.
+**
+** ^The string value returned by this routine is owned and managed by
+** the database connection.  ^The value will be valid until the database N
+** is [DETACH]-ed or until the database connection closes.
+**
+** ^The filename returned by this function is the output of the
+** xFullPathname method of the [VFS].  ^In other words, the filename
+** will be an absolute pathname, even if the filename used
+** to open the database originally was a URI or relative pathname.
+**
+** If the filename pointer returned by this routine is not NULL, then it
+** can be used as the filename input parameter to these routines:
+** <ul>
+** <li> [sqlite3_uri_parameter()]
+** <li> [sqlite3_uri_boolean()]
+** <li> [sqlite3_uri_int64()]
+** <li> [sqlite3_filename_database()]
+** <li> [sqlite3_filename_journal()]
+** <li> [sqlite3_filename_wal()]
+** </ul>
+*/
+SQLITE_API sqlite3_filename sqlite3_db_filename(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine if a database is read-only
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
+** of connection D is read-only, 0 if it is read/write, or -1 if N is not
+** the name of a database on connection D.
+*/
+SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
+
+/*
+** CAPI3REF: Determine the transaction state of a database
+** METHOD: sqlite3
+**
+** ^The sqlite3_txn_state(D,S) interface returns the current
+** [transaction state] of schema S in database connection D.  ^If S is NULL,
+** then the highest transaction state of any schema on database connection D
+** is returned.  Transaction states are (in order of lowest to highest):
+** <ol>
+** <li value="0"> SQLITE_TXN_NONE
+** <li value="1"> SQLITE_TXN_READ
+** <li value="2"> SQLITE_TXN_WRITE
+** </ol>
+** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
+** a valid schema, then -1 is returned.
+*/
+SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
+
+/*
+** CAPI3REF: Allowed return values from sqlite3_txn_state()
+** KEYWORDS: {transaction state}
+**
+** These constants define the current transaction state of a database file.
+** ^The [sqlite3_txn_state(D,S)] interface returns one of these
+** constants in order to describe the transaction state of schema S
+** in [database connection] D.
+**
+** <dl>
+** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
+** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
+** pending.</dd>
+**
+** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
+** <dd>The SQLITE_TXN_READ state means that the database is currently
+** in a read transaction.  Content has been read from the database file
+** but nothing in the database file has changed.  The transaction state
+** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
+** no other conflicting concurrent write transactions.  The transaction
+** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
+** [COMMIT].</dd>
+**
+** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
+** <dd>The SQLITE_TXN_WRITE state means that the database is currently
+** in a write transaction.  Content has been written to the database file
+** but has not yet committed.  The transaction state will change to
+** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
+*/
+#define SQLITE_TXN_NONE  0
+#define SQLITE_TXN_READ  1
+#define SQLITE_TXN_WRITE 2
+
+/*
+** CAPI3REF: Find the next prepared statement
+** METHOD: sqlite3
+**
+** ^This interface returns a pointer to the next [prepared statement] after
+** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
+** then this interface returns a pointer to the first prepared statement
+** associated with the database connection pDb.  ^If no prepared statement
+** satisfies the conditions of this routine, it returns NULL.
+**
+** The [database connection] pointer D in a call to
+** [sqlite3_next_stmt(D,S)] must refer to an open database
+** connection and in particular must not be a NULL pointer.
+*/
+SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
+
+/*
+** CAPI3REF: Commit And Rollback Notification Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_commit_hook() interface registers a callback
+** function to be invoked whenever a transaction is [COMMIT | committed].
+** ^Any callback set by a previous call to sqlite3_commit_hook()
+** for the same database connection is overridden.
+** ^The sqlite3_rollback_hook() interface registers a callback
+** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
+** ^Any callback set by a previous call to sqlite3_rollback_hook()
+** for the same database connection is overridden.
+** ^The pArg argument is passed through to the callback.
+** ^If the callback on a commit hook function returns non-zero,
+** then the commit is converted into a rollback.
+**
+** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
+** return the P argument from the previous call of the same function
+** on the same [database connection] D, or NULL for
+** the first call for each function on D.
+**
+** The commit and rollback hook callbacks are not reentrant.
+** The callback implementation must not do anything that will modify
+** the database connection that invoked the callback.  Any actions
+** to modify the database connection must be deferred until after the
+** completion of the [sqlite3_step()] call that triggered the commit
+** or rollback hook in the first place.
+** Note that running any other SQL statements, including SELECT statements,
+** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
+** the database connections for the meaning of "modify" in this paragraph.
+**
+** ^Registering a NULL function disables the callback.
+**
+** ^When the commit hook callback routine returns zero, the [COMMIT]
+** operation is allowed to continue normally.  ^If the commit hook
+** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
+** ^The rollback hook is invoked on a rollback that results from a commit
+** hook returning non-zero, just as it would be with any other rollback.
+**
+** ^For the purposes of this API, a transaction is said to have been
+** rolled back if an explicit "ROLLBACK" statement is executed, or
+** an error or constraint causes an implicit rollback to occur.
+** ^The rollback callback is not invoked if a transaction is
+** automatically rolled back because the database connection is closed.
+**
+** See also the [sqlite3_update_hook()] interface.
+*/
+SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
+SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
+
+/*
+** CAPI3REF: Autovacuum Compaction Amount Callback
+** METHOD: sqlite3
+**
+** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
+** function C that is invoked prior to each autovacuum of the database
+** file.  ^The callback is passed a copy of the generic data pointer (P),
+** the schema-name of the attached database that is being autovacuumed,
+** the size of the database file in pages, the number of free pages,
+** and the number of bytes per page, respectively.  The callback should
+** return the number of free pages that should be removed by the
+** autovacuum.  ^If the callback returns zero, then no autovacuum happens.
+** ^If the value returned is greater than or equal to the number of
+** free pages, then a complete autovacuum happens.
+**
+** <p>^If there are multiple ATTACH-ed database files that are being
+** modified as part of a transaction commit, then the autovacuum pages
+** callback is invoked separately for each file.
+**
+** <p><b>The callback is not reentrant.</b> The callback function should
+** not attempt to invoke any other SQLite interface.  If it does, bad
+** things may happen, including segmentation faults and corrupt database
+** files.  The callback function should be a simple function that
+** does some arithmetic on its input parameters and returns a result.
+**
+** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
+** destructor for the P parameter.  ^If X is not NULL, then X(P) is
+** invoked whenever the database connection closes or when the callback
+** is overwritten by another invocation of sqlite3_autovacuum_pages().
+**
+** <p>^There is only one autovacuum pages callback per database connection.
+** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
+** previous invocations for that database connection.  ^If the callback
+** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
+** then the autovacuum steps callback is canceled.  The return value
+** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
+** be some other error code if something goes wrong.  The current
+** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
+** return codes might be added in future releases.
+**
+** <p>If no autovacuum pages callback is specified (the usual case) or
+** a NULL pointer is provided for the callback,
+** then the default behavior is to vacuum all free pages.  So, in other
+** words, the default behavior is the same as if the callback function
+** were something like this:
+**
+** <blockquote><pre>
+**     unsigned int demonstration_autovac_pages_callback(
+**       void *pClientData,
+**       const char *zSchema,
+**       unsigned int nDbPage,
+**       unsigned int nFreePage,
+**       unsigned int nBytePerPage
+**     ){
+**       return nFreePage;
+**     }
+** </pre></blockquote>
+*/
+SQLITE_API int sqlite3_autovacuum_pages(
+  sqlite3 *db,
+  unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
+  void*,
+  void(*)(void*)
+);
+
+
+/*
+** CAPI3REF: Data Change Notification Callbacks
+** METHOD: sqlite3
+**
+** ^The sqlite3_update_hook() interface registers a callback function
+** with the [database connection] identified by the first argument
+** to be invoked whenever a row is updated, inserted or deleted in
+** a [rowid table].
+** ^Any callback set by a previous call to this function
+** for the same database connection is overridden.
+**
+** ^The second argument is a pointer to the function to invoke when a
+** row is updated, inserted or deleted in a rowid table.
+** ^The first argument to the callback is a copy of the third argument
+** to sqlite3_update_hook().
+** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
+** or [SQLITE_UPDATE], depending on the operation that caused the callback
+** to be invoked.
+** ^The third and fourth arguments to the callback contain pointers to the
+** database and table name containing the affected row.
+** ^The final callback parameter is the [rowid] of the row.
+** ^In the case of an update, this is the [rowid] after the update takes place.
+**
+** ^(The update hook is not invoked when internal system tables are
+** modified (i.e. sqlite_sequence).)^
+** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
+**
+** ^In the current implementation, the update hook
+** is not invoked when conflicting rows are deleted because of an
+** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
+** invoked when rows are deleted using the [truncate optimization].
+** The exceptions defined in this paragraph might change in a future
+** release of SQLite.
+**
+** Whether the update hook is invoked before or after the
+** corresponding change is currently unspecified and may differ
+** depending on the type of change. Do not rely on the order of the
+** hook call with regards to the final result of the operation which
+** triggers the hook.
+**
+** The update hook implementation must not do anything that will modify
+** the database connection that invoked the update hook.  Any actions
+** to modify the database connection must be deferred until after the
+** completion of the [sqlite3_step()] call that triggered the update hook.
+** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
+** database connections for the meaning of "modify" in this paragraph.
+**
+** ^The sqlite3_update_hook(D,C,P) function
+** returns the P argument from the previous call
+** on the same [database connection] D, or NULL for
+** the first call on D.
+**
+** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
+** and [sqlite3_preupdate_hook()] interfaces.
+*/
+SQLITE_API void *sqlite3_update_hook(
+  sqlite3*,
+  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
+  void*
+);
+
+/*
+** CAPI3REF: Enable Or Disable Shared Pager Cache
+**
+** ^(This routine enables or disables the sharing of the database cache
+** and schema data structures between [database connection | connections]
+** to the same database. Sharing is enabled if the argument is true
+** and disabled if the argument is false.)^
+**
+** This interface is omitted if SQLite is compiled with
+** [-DSQLITE_OMIT_SHARED_CACHE].  The [-DSQLITE_OMIT_SHARED_CACHE]
+** compile-time option is recommended because the
+** [use of shared cache mode is discouraged].
+**
+** ^Cache sharing is enabled and disabled for an entire process.
+** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
+** In prior versions of SQLite,
+** sharing was enabled or disabled for each thread separately.
+**
+** ^(The cache sharing mode set by this interface effects all subsequent
+** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
+** Existing database connections continue to use the sharing mode
+** that was in effect at the time they were opened.)^
+**
+** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
+** successfully.  An [error code] is returned otherwise.)^
+**
+** ^Shared cache is disabled by default. It is recommended that it stay
+** that way.  In other words, do not use this routine.  This interface
+** continues to be provided for historical compatibility, but its use is
+** discouraged.  Any use of shared cache is discouraged.  If shared cache
+** must be used, it is recommended that shared cache only be enabled for
+** individual database connections using the [sqlite3_open_v2()] interface
+** with the [SQLITE_OPEN_SHAREDCACHE] flag.
+**
+** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
+** and will always return SQLITE_MISUSE. On those systems,
+** shared cache mode should be enabled per-database connection via
+** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
+**
+** This interface is threadsafe on processors where writing a
+** 32-bit integer is atomic.
+**
+** See Also:  [SQLite Shared-Cache Mode]
+*/
+SQLITE_API int sqlite3_enable_shared_cache(int);
+
+/*
+** CAPI3REF: Attempt To Free Heap Memory
+**
+** ^The sqlite3_release_memory() interface attempts to free N bytes
+** of heap memory by deallocating non-essential memory allocations
+** held by the database library.   Memory used to cache database
+** pages to improve performance is an example of non-essential memory.
+** ^sqlite3_release_memory() returns the number of bytes actually freed,
+** which might be more or less than the amount requested.
+** ^The sqlite3_release_memory() routine is a no-op returning zero
+** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
+**
+** See also: [sqlite3_db_release_memory()]
+*/
+SQLITE_API int sqlite3_release_memory(int);
+
+/*
+** CAPI3REF: Free Memory Used By A Database Connection
+** METHOD: sqlite3
+**
+** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
+** memory as possible from database connection D. Unlike the
+** [sqlite3_release_memory()] interface, this interface is in effect even
+** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
+** omitted.
+**
+** See also: [sqlite3_release_memory()]
+*/
+SQLITE_API int sqlite3_db_release_memory(sqlite3*);
+
+/*
+** CAPI3REF: Impose A Limit On Heap Size
+**
+** These interfaces impose limits on the amount of heap memory that will be
+** by all database connections within a single process.
+**
+** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
+** soft limit on the amount of heap memory that may be allocated by SQLite.
+** ^SQLite strives to keep heap memory utilization below the soft heap
+** limit by reducing the number of pages held in the page cache
+** as heap memory usages approaches the limit.
+** ^The soft heap limit is "soft" because even though SQLite strives to stay
+** below the limit, it will exceed the limit rather than generate
+** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
+** is advisory only.
+**
+** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
+** N bytes on the amount of memory that will be allocated.  ^The
+** sqlite3_hard_heap_limit64(N) interface is similar to
+** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
+** when the hard heap limit is reached.
+**
+** ^The return value from both sqlite3_soft_heap_limit64() and
+** sqlite3_hard_heap_limit64() is the size of
+** the heap limit prior to the call, or negative in the case of an
+** error.  ^If the argument N is negative
+** then no change is made to the heap limit.  Hence, the current
+** size of heap limits can be determined by invoking
+** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
+**
+** ^Setting the heap limits to zero disables the heap limiter mechanism.
+**
+** ^The soft heap limit may not be greater than the hard heap limit.
+** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
+** is invoked with a value of N that is greater than the hard heap limit,
+** the soft heap limit is set to the value of the hard heap limit.
+** ^The soft heap limit is automatically enabled whenever the hard heap
+** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
+** the soft heap limit is outside the range of 1..N, then the soft heap
+** limit is set to N.  ^Invoking sqlite3_soft_heap_limit64(0) when the
+** hard heap limit is enabled makes the soft heap limit equal to the
+** hard heap limit.
+**
+** The memory allocation limits can also be adjusted using
+** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
+**
+** ^(The heap limits are not enforced in the current implementation
+** if one or more of following conditions are true:
+**
+** <ul>
+** <li> The limit value is set to zero.
+** <li> Memory accounting is disabled using a combination of the
+**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
+**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
+** <li> An alternative page cache implementation is specified using
+**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
+** <li> The page cache allocates from its own memory pool supplied
+**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
+**      from the heap.
+** </ul>)^
+**
+** The circumstances under which SQLite will enforce the heap limits may
+** changes in future releases of SQLite.
+*/
+SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
+SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
+
+/*
+** CAPI3REF: Deprecated Soft Heap Limit Interface
+** DEPRECATED
+**
+** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
+** interface.  This routine is provided for historical compatibility
+** only.  All new applications should use the
+** [sqlite3_soft_heap_limit64()] interface rather than this one.
+*/
+SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
+
+
+/*
+** CAPI3REF: Extract Metadata About A Column Of A Table
+** METHOD: sqlite3
+**
+** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
+** information about column C of table T in database D
+** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
+** interface returns SQLITE_OK and fills in the non-NULL pointers in
+** the final five arguments with appropriate values if the specified
+** column exists.  ^The sqlite3_table_column_metadata() interface returns
+** SQLITE_ERROR if the specified column does not exist.
+** ^If the column-name parameter to sqlite3_table_column_metadata() is a
+** NULL pointer, then this routine simply checks for the existence of the
+** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
+** does not.  If the table name parameter T in a call to
+** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
+** undefined behavior.
+**
+** ^The column is identified by the second, third and fourth parameters to
+** this function. ^(The second parameter is either the name of the database
+** (i.e. "main", "temp", or an attached database) containing the specified
+** table or NULL.)^ ^If it is NULL, then all attached databases are searched
+** for the table using the same algorithm used by the database engine to
+** resolve unqualified table references.
+**
+** ^The third and fourth parameters to this function are the table and column
+** name of the desired column, respectively.
+**
+** ^Metadata is returned by writing to the memory locations passed as the 5th
+** and subsequent parameters to this function. ^Any of these arguments may be
+** NULL, in which case the corresponding element of metadata is omitted.
+**
+** ^(<blockquote>
+** <table border="1">
+** <tr><th> Parameter <th> Output<br>Type <th>  Description
+**
+** <tr><td> 5th <td> const char* <td> Data type
+** <tr><td> 6th <td> const char* <td> Name of default collation sequence
+** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
+** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
+** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
+** </table>
+** </blockquote>)^
+**
+** ^The memory pointed to by the character pointers returned for the
+** declaration type and collation sequence is valid until the next
+** call to any SQLite API function.
+**
+** ^If the specified table is actually a view, an [error code] is returned.
+**
+** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
+** is not a [WITHOUT ROWID] table and an
+** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
+** parameters are set for the explicitly declared column. ^(If there is no
+** [INTEGER PRIMARY KEY] column, then the outputs
+** for the [rowid] are set as follows:
+**
+** <pre>
+**     data type: "INTEGER"
+**     collation sequence: "BINARY"
+**     not null: 0
+**     primary key: 1
+**     auto increment: 0
+** </pre>)^
+**
+** ^This function causes all database schemas to be read from disk and
+** parsed, if that has not already been done, and returns an error if
+** any errors are encountered while loading the schema.
+*/
+SQLITE_API int sqlite3_table_column_metadata(
+  sqlite3 *db,                /* Connection handle */
+  const char *zDbName,        /* Database name or NULL */
+  const char *zTableName,     /* Table name */
+  const char *zColumnName,    /* Column name */
+  char const **pzDataType,    /* OUTPUT: Declared data type */
+  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
+  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
+  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
+  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
+);
+
+/*
+** CAPI3REF: Load An Extension
+** METHOD: sqlite3
+**
+** ^This interface loads an SQLite extension library from the named file.
+**
+** ^The sqlite3_load_extension() interface attempts to load an
+** [SQLite extension] library contained in the file zFile.  If
+** the file cannot be loaded directly, attempts are made to load
+** with various operating-system specific extensions added.
+** So for example, if "samplelib" cannot be loaded, then names like
+** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
+** be tried also.
+**
+** ^The entry point is zProc.
+** ^(zProc may be 0, in which case SQLite will try to come up with an
+** entry point name on its own.  It first tries "sqlite3_extension_init".
+** If that does not work, it constructs a name "sqlite3_X_init" where the
+** X is consists of the lower-case equivalent of all ASCII alphabetic
+** characters in the filename from the last "/" to the first following
+** "." and omitting any initial "lib".)^
+** ^The sqlite3_load_extension() interface returns
+** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
+** ^If an error occurs and pzErrMsg is not 0, then the
+** [sqlite3_load_extension()] interface shall attempt to
+** fill *pzErrMsg with error message text stored in memory
+** obtained from [sqlite3_malloc()]. The calling function
+** should free this memory by calling [sqlite3_free()].
+**
+** ^Extension loading must be enabled using
+** [sqlite3_enable_load_extension()] or
+** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
+** prior to calling this API,
+** otherwise an error will be returned.
+**
+** <b>Security warning:</b> It is recommended that the
+** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
+** interface.  The use of the [sqlite3_enable_load_extension()] interface
+** should be avoided.  This will keep the SQL function [load_extension()]
+** disabled and prevent SQL injections from giving attackers
+** access to extension loading capabilities.
+**
+** See also the [load_extension() SQL function].
+*/
+SQLITE_API int sqlite3_load_extension(
+  sqlite3 *db,          /* Load the extension into this database connection */
+  const char *zFile,    /* Name of the shared library containing extension */
+  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
+  char **pzErrMsg       /* Put error message here if not 0 */
+);
+
+/*
+** CAPI3REF: Enable Or Disable Extension Loading
+** METHOD: sqlite3
+**
+** ^So as not to open security holes in older applications that are
+** unprepared to deal with [extension loading], and as a means of disabling
+** [extension loading] while evaluating user-entered SQL, the following API
+** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
+**
+** ^Extension loading is off by default.
+** ^Call the sqlite3_enable_load_extension() routine with onoff==1
+** to turn extension loading on and call it with onoff==0 to turn
+** it back off again.
+**
+** ^This interface enables or disables both the C-API
+** [sqlite3_load_extension()] and the SQL function [load_extension()].
+** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
+** to enable or disable only the C-API.)^
+**
+** <b>Security warning:</b> It is recommended that extension loading
+** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
+** rather than this interface, so the [load_extension()] SQL function
+** remains disabled. This will prevent SQL injections from giving attackers
+** access to extension loading capabilities.
+*/
+SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
+
+/*
+** CAPI3REF: Automatically Load Statically Linked Extensions
+**
+** ^This interface causes the xEntryPoint() function to be invoked for
+** each new [database connection] that is created.  The idea here is that
+** xEntryPoint() is the entry point for a statically linked [SQLite extension]
+** that is to be automatically loaded into all new database connections.
+**
+** ^(Even though the function prototype shows that xEntryPoint() takes
+** no arguments and returns void, SQLite invokes xEntryPoint() with three
+** arguments and expects an integer result as if the signature of the
+** entry point where as follows:
+**
+** <blockquote><pre>
+**    int xEntryPoint(
+**      sqlite3 *db,
+**      const char **pzErrMsg,
+**      const struct sqlite3_api_routines *pThunk
+**    );
+** </pre></blockquote>)^
+**
+** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
+** point to an appropriate error message (obtained from [sqlite3_mprintf()])
+** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
+** is NULL before calling the xEntryPoint().  ^SQLite will invoke
+** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
+** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
+** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
+**
+** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
+** on the list of automatic extensions is a harmless no-op. ^No entry point
+** will be called more than once for each database connection that is opened.
+**
+** See also: [sqlite3_reset_auto_extension()]
+** and [sqlite3_cancel_auto_extension()]
+*/
+SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
+
+/*
+** CAPI3REF: Cancel Automatic Extension Loading
+**
+** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
+** initialization routine X that was registered using a prior call to
+** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
+** routine returns 1 if initialization routine X was successfully
+** unregistered and it returns 0 if X was not on the list of initialization
+** routines.
+*/
+SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
+
+/*
+** CAPI3REF: Reset Automatic Extension Loading
+**
+** ^This interface disables all automatic extensions previously
+** registered using [sqlite3_auto_extension()].
+*/
+SQLITE_API void sqlite3_reset_auto_extension(void);
+
+/*
+** Structures used by the virtual table interface
+*/
+typedef struct sqlite3_vtab sqlite3_vtab;
+typedef struct sqlite3_index_info sqlite3_index_info;
+typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
+typedef struct sqlite3_module sqlite3_module;
+
+/*
+** CAPI3REF: Virtual Table Object
+** KEYWORDS: sqlite3_module {virtual table module}
+**
+** This structure, sometimes called a "virtual table module",
+** defines the implementation of a [virtual table].
+** This structure consists mostly of methods for the module.
+**
+** ^A virtual table module is created by filling in a persistent
+** instance of this structure and passing a pointer to that instance
+** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
+** ^The registration remains valid until it is replaced by a different
+** module or until the [database connection] closes.  The content
+** of this structure must not change while it is registered with
+** any database connection.
+*/
+struct sqlite3_module {
+  int iVersion;
+  int (*xCreate)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xConnect)(sqlite3*, void *pAux,
+               int argc, const char *const*argv,
+               sqlite3_vtab **ppVTab, char**);
+  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
+  int (*xDisconnect)(sqlite3_vtab *pVTab);
+  int (*xDestroy)(sqlite3_vtab *pVTab);
+  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
+  int (*xClose)(sqlite3_vtab_cursor*);
+  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
+                int argc, sqlite3_value **argv);
+  int (*xNext)(sqlite3_vtab_cursor*);
+  int (*xEof)(sqlite3_vtab_cursor*);
+  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
+  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
+  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
+  int (*xBegin)(sqlite3_vtab *pVTab);
+  int (*xSync)(sqlite3_vtab *pVTab);
+  int (*xCommit)(sqlite3_vtab *pVTab);
+  int (*xRollback)(sqlite3_vtab *pVTab);
+  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
+                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
+                       void **ppArg);
+  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
+  /* The methods above are in version 1 of the sqlite_module object. Those
+  ** below are for version 2 and greater. */
+  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
+  int (*xRelease)(sqlite3_vtab *pVTab, int);
+  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
+  /* The methods above are in versions 1 and 2 of the sqlite_module object.
+  ** Those below are for version 3 and greater. */
+  int (*xShadowName)(const char*);
+  /* The methods above are in versions 1 through 3 of the sqlite_module object.
+  ** Those below are for version 4 and greater. */
+  int (*xIntegrity)(sqlite3_vtab *pVTab, const char *zSchema,
+                    const char *zTabName, int mFlags, char **pzErr);
+};
+
+/*
+** CAPI3REF: Virtual Table Indexing Information
+** KEYWORDS: sqlite3_index_info
+**
+** The sqlite3_index_info structure and its substructures is used as part
+** of the [virtual table] interface to
+** pass information into and receive the reply from the [xBestIndex]
+** method of a [virtual table module].  The fields under **Inputs** are the
+** inputs to xBestIndex and are read-only.  xBestIndex inserts its
+** results into the **Outputs** fields.
+**
+** ^(The aConstraint[] array records WHERE clause constraints of the form:
+**
+** <blockquote>column OP expr</blockquote>
+**
+** where OP is =, <, <=, >, or >=.)^  ^(The particular operator is
+** stored in aConstraint[].op using one of the
+** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
+** ^(The index of the column is stored in
+** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
+** expr on the right-hand side can be evaluated (and thus the constraint
+** is usable) and false if it cannot.)^
+**
+** ^The optimizer automatically inverts terms of the form "expr OP column"
+** and makes other simplifications to the WHERE clause in an attempt to
+** get as many WHERE clause terms into the form shown above as possible.
+** ^The aConstraint[] array only reports WHERE clause terms that are
+** relevant to the particular virtual table being queried.
+**
+** ^Information about the ORDER BY clause is stored in aOrderBy[].
+** ^Each term of aOrderBy records a column of the ORDER BY clause.
+**
+** The colUsed field indicates which columns of the virtual table may be
+** required by the current scan. Virtual table columns are numbered from
+** zero in the order in which they appear within the CREATE TABLE statement
+** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
+** the corresponding bit is set within the colUsed mask if the column may be
+** required by SQLite. If the table has at least 64 columns and any column
+** to the right of the first 63 is required, then bit 63 of colUsed is also
+** set. In other words, column iCol may be required if the expression
+** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
+** non-zero.
+**
+** The [xBestIndex] method must fill aConstraintUsage[] with information
+** about what parameters to pass to xFilter.  ^If argvIndex>0 then
+** the right-hand side of the corresponding aConstraint[] is evaluated
+** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
+** is true, then the constraint is assumed to be fully handled by the
+** virtual table and might not be checked again by the byte code.)^ ^(The
+** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
+** is left in its default setting of false, the constraint will always be
+** checked separately in byte code.  If the omit flag is change to true, then
+** the constraint may or may not be checked in byte code.  In other words,
+** when the omit flag is true there is no guarantee that the constraint will
+** not be checked again using byte code.)^
+**
+** ^The idxNum and idxStr values are recorded and passed into the
+** [xFilter] method.
+** ^[sqlite3_free()] is used to free idxStr if and only if
+** needToFreeIdxStr is true.
+**
+** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
+** the correct order to satisfy the ORDER BY clause so that no separate
+** sorting step is required.
+**
+** ^The estimatedCost value is an estimate of the cost of a particular
+** strategy. A cost of N indicates that the cost of the strategy is similar
+** to a linear scan of an SQLite table with N rows. A cost of log(N)
+** indicates that the expense of the operation is similar to that of a
+** binary search on a unique indexed field of an SQLite table with N rows.
+**
+** ^The estimatedRows value is an estimate of the number of rows that
+** will be returned by the strategy.
+**
+** The xBestIndex method may optionally populate the idxFlags field with a
+** mask of SQLITE_INDEX_SCAN_* flags. One such flag is
+** [SQLITE_INDEX_SCAN_HEX], which if set causes the [EXPLAIN QUERY PLAN]
+** output to show the idxNum has hex instead of as decimal.  Another flag is
+** SQLITE_INDEX_SCAN_UNIQUE, which if set indicates that the query plan will
+** return at most one row.
+**
+** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
+** SQLite also assumes that if a call to the xUpdate() method is made as
+** part of the same statement to delete or update a virtual table row and the
+** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
+** any database changes. In other words, if the xUpdate() returns
+** SQLITE_CONSTRAINT, the database contents must be exactly as they were
+** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
+** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
+** the xUpdate method are automatically rolled back by SQLite.
+**
+** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
+** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
+** If a virtual table extension is
+** used with an SQLite version earlier than 3.8.2, the results of attempting
+** to read or write the estimatedRows field are undefined (but are likely
+** to include crashing the application). The estimatedRows field should
+** therefore only be used if [sqlite3_libversion_number()] returns a
+** value greater than or equal to 3008002. Similarly, the idxFlags field
+** was added for [version 3.9.0] ([dateof:3.9.0]).
+** It may therefore only be used if
+** sqlite3_libversion_number() returns a value greater than or equal to
+** 3009000.
+*/
+struct sqlite3_index_info {
+  /* Inputs */
+  int nConstraint;           /* Number of entries in aConstraint */
+  struct sqlite3_index_constraint {
+     int iColumn;              /* Column constrained.  -1 for ROWID */
+     unsigned char op;         /* Constraint operator */
+     unsigned char usable;     /* True if this constraint is usable */
+     int iTermOffset;          /* Used internally - xBestIndex should ignore */
+  } *aConstraint;            /* Table of WHERE clause constraints */
+  int nOrderBy;              /* Number of terms in the ORDER BY clause */
+  struct sqlite3_index_orderby {
+     int iColumn;              /* Column number */
+     unsigned char desc;       /* True for DESC.  False for ASC. */
+  } *aOrderBy;               /* The ORDER BY clause */
+  /* Outputs */
+  struct sqlite3_index_constraint_usage {
+    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
+    unsigned char omit;      /* Do not code a test for this constraint */
+  } *aConstraintUsage;
+  int idxNum;                /* Number used to identify the index */
+  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
+  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
+  int orderByConsumed;       /* True if output is already ordered */
+  double estimatedCost;           /* Estimated cost of using this index */
+  /* Fields below are only available in SQLite 3.8.2 and later */
+  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
+  /* Fields below are only available in SQLite 3.9.0 and later */
+  int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
+  /* Fields below are only available in SQLite 3.10.0 and later */
+  sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
+};
+
+/*
+** CAPI3REF: Virtual Table Scan Flags
+**
+** Virtual table implementations are allowed to set the
+** [sqlite3_index_info].idxFlags field to some combination of
+** these bits.
+*/
+#define SQLITE_INDEX_SCAN_UNIQUE 0x00000001 /* Scan visits at most 1 row */
+#define SQLITE_INDEX_SCAN_HEX    0x00000002 /* Display idxNum as hex */
+                                            /* in EXPLAIN QUERY PLAN */
+
+/*
+** CAPI3REF: Virtual Table Constraint Operator Codes
+**
+** These macros define the allowed values for the
+** [sqlite3_index_info].aConstraint[].op field.  Each value represents
+** an operator that is part of a constraint term in the WHERE clause of
+** a query that uses a [virtual table].
+**
+** ^The left-hand operand of the operator is given by the corresponding
+** aConstraint[].iColumn field.  ^An iColumn of -1 indicates the left-hand
+** operand is the rowid.
+** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
+** operators have no left-hand operand, and so for those operators the
+** corresponding aConstraint[].iColumn is meaningless and should not be
+** used.
+**
+** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
+** value 255 are reserved to represent functions that are overloaded
+** by the [xFindFunction|xFindFunction method] of the virtual table
+** implementation.
+**
+** The right-hand operands for each constraint might be accessible using
+** the [sqlite3_vtab_rhs_value()] interface.  Usually the right-hand
+** operand is only available if it appears as a single constant literal
+** in the input SQL.  If the right-hand operand is another column or an
+** expression (even a constant expression) or a parameter, then the
+** sqlite3_vtab_rhs_value() probably will not be able to extract it.
+** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
+** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
+** and hence calls to sqlite3_vtab_rhs_value() for those operators will
+** always return SQLITE_NOTFOUND.
+**
+** The collating sequence to be used for comparison can be found using
+** the [sqlite3_vtab_collation()] interface.  For most real-world virtual
+** tables, the collating sequence of constraints does not matter (for example
+** because the constraints are numeric) and so the sqlite3_vtab_collation()
+** interface is not commonly needed.
+*/
+#define SQLITE_INDEX_CONSTRAINT_EQ          2
+#define SQLITE_INDEX_CONSTRAINT_GT          4
+#define SQLITE_INDEX_CONSTRAINT_LE          8
+#define SQLITE_INDEX_CONSTRAINT_LT         16
+#define SQLITE_INDEX_CONSTRAINT_GE         32
+#define SQLITE_INDEX_CONSTRAINT_MATCH      64
+#define SQLITE_INDEX_CONSTRAINT_LIKE       65
+#define SQLITE_INDEX_CONSTRAINT_GLOB       66
+#define SQLITE_INDEX_CONSTRAINT_REGEXP     67
+#define SQLITE_INDEX_CONSTRAINT_NE         68
+#define SQLITE_INDEX_CONSTRAINT_ISNOT      69
+#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL  70
+#define SQLITE_INDEX_CONSTRAINT_ISNULL     71
+#define SQLITE_INDEX_CONSTRAINT_IS         72
+#define SQLITE_INDEX_CONSTRAINT_LIMIT      73
+#define SQLITE_INDEX_CONSTRAINT_OFFSET     74
+#define SQLITE_INDEX_CONSTRAINT_FUNCTION  150
+
+/*
+** CAPI3REF: Register A Virtual Table Implementation
+** METHOD: sqlite3
+**
+** ^These routines are used to register a new [virtual table module] name.
+** ^Module names must be registered before
+** creating a new [virtual table] using the module and before using a
+** preexisting [virtual table] for the module.
+**
+** ^The module name is registered on the [database connection] specified
+** by the first parameter.  ^The name of the module is given by the
+** second parameter.  ^The third parameter is a pointer to
+** the implementation of the [virtual table module].   ^The fourth
+** parameter is an arbitrary client data pointer that is passed through
+** into the [xCreate] and [xConnect] methods of the virtual table module
+** when a new virtual table is be being created or reinitialized.
+**
+** ^The sqlite3_create_module_v2() interface has a fifth parameter which
+** is a pointer to a destructor for the pClientData.  ^SQLite will
+** invoke the destructor function (if it is not NULL) when SQLite
+** no longer needs the pClientData pointer.  ^The destructor will also
+** be invoked if the call to sqlite3_create_module_v2() fails.
+** ^The sqlite3_create_module()
+** interface is equivalent to sqlite3_create_module_v2() with a NULL
+** destructor.
+**
+** ^If the third parameter (the pointer to the sqlite3_module object) is
+** NULL then no new module is created and any existing modules with the
+** same name are dropped.
+**
+** See also: [sqlite3_drop_modules()]
+*/
+SQLITE_API int sqlite3_create_module(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData          /* Client data for xCreate/xConnect */
+);
+SQLITE_API int sqlite3_create_module_v2(
+  sqlite3 *db,               /* SQLite connection to register module with */
+  const char *zName,         /* Name of the module */
+  const sqlite3_module *p,   /* Methods for the module */
+  void *pClientData,         /* Client data for xCreate/xConnect */
+  void(*xDestroy)(void*)     /* Module destructor function */
+);
+
+/*
+** CAPI3REF: Remove Unnecessary Virtual Table Implementations
+** METHOD: sqlite3
+**
+** ^The sqlite3_drop_modules(D,L) interface removes all virtual
+** table modules from database connection D except those named on list L.
+** The L parameter must be either NULL or a pointer to an array of pointers
+** to strings where the array is terminated by a single NULL pointer.
+** ^If the L parameter is NULL, then all virtual table modules are removed.
+**
+** See also: [sqlite3_create_module()]
+*/
+SQLITE_API int sqlite3_drop_modules(
+  sqlite3 *db,                /* Remove modules from this connection */
+  const char **azKeep         /* Except, do not remove the ones named here */
+);
+
+/*
+** CAPI3REF: Virtual Table Instance Object
+** KEYWORDS: sqlite3_vtab
+**
+** Every [virtual table module] implementation uses a subclass
+** of this object to describe a particular instance
+** of the [virtual table].  Each subclass will
+** be tailored to the specific needs of the module implementation.
+** The purpose of this superclass is to define certain fields that are
+** common to all module implementations.
+**
+** ^Virtual tables methods can set an error message by assigning a
+** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
+** take care that any prior string is freed by a call to [sqlite3_free()]
+** prior to assigning a new string to zErrMsg.  ^After the error message
+** is delivered up to the client application, the string will be automatically
+** freed by sqlite3_free() and the zErrMsg field will be zeroed.
+*/
+struct sqlite3_vtab {
+  const sqlite3_module *pModule;  /* The module for this virtual table */
+  int nRef;                       /* Number of open cursors */
+  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Virtual Table Cursor Object
+** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
+**
+** Every [virtual table module] implementation uses a subclass of the
+** following structure to describe cursors that point into the
+** [virtual table] and are used
+** to loop through the virtual table.  Cursors are created using the
+** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
+** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
+** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
+** of the module.  Each module implementation will define
+** the content of a cursor structure to suit its own needs.
+**
+** This superclass exists in order to define fields of the cursor that
+** are common to all implementations.
+*/
+struct sqlite3_vtab_cursor {
+  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
+  /* Virtual table implementations will typically add additional fields */
+};
+
+/*
+** CAPI3REF: Declare The Schema Of A Virtual Table
+**
+** ^The [xCreate] and [xConnect] methods of a
+** [virtual table module] call this interface
+** to declare the format (the names and datatypes of the columns) of
+** the virtual tables they implement.
+*/
+SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
+
+/*
+** CAPI3REF: Overload A Function For A Virtual Table
+** METHOD: sqlite3
+**
+** ^(Virtual tables can provide alternative implementations of functions
+** using the [xFindFunction] method of the [virtual table module].
+** But global versions of those functions
+** must exist in order to be overloaded.)^
+**
+** ^(This API makes sure a global version of a function with a particular
+** name and number of parameters exists.  If no such function exists
+** before this API is called, a new function is created.)^  ^The implementation
+** of the new function always causes an exception to be thrown.  So
+** the new function is not good for anything by itself.  Its only
+** purpose is to be a placeholder function that can be overloaded
+** by a [virtual table].
+*/
+SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
+
+/*
+** CAPI3REF: A Handle To An Open BLOB
+** KEYWORDS: {BLOB handle} {BLOB handles}
+**
+** An instance of this object represents an open BLOB on which
+** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
+** ^Objects of this type are created by [sqlite3_blob_open()]
+** and destroyed by [sqlite3_blob_close()].
+** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
+** can be used to read or write small subsections of the BLOB.
+** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
+*/
+typedef struct sqlite3_blob sqlite3_blob;
+
+/*
+** CAPI3REF: Open A BLOB For Incremental I/O
+** METHOD: sqlite3
+** CONSTRUCTOR: sqlite3_blob
+**
+** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
+** in row iRow, column zColumn, table zTable in database zDb;
+** in other words, the same BLOB that would be selected by:
+**
+** <pre>
+**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
+** </pre>)^
+**
+** ^(Parameter zDb is not the filename that contains the database, but
+** rather the symbolic name of the database. For attached databases, this is
+** the name that appears after the AS keyword in the [ATTACH] statement.
+** For the main database file, the database name is "main". For TEMP
+** tables, the database name is "temp".)^
+**
+** ^If the flags parameter is non-zero, then the BLOB is opened for read
+** and write access. ^If the flags parameter is zero, the BLOB is opened for
+** read-only access.
+**
+** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
+** in *ppBlob. Otherwise an [error code] is returned and, unless the error
+** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
+** the API is not misused, it is always safe to call [sqlite3_blob_close()]
+** on *ppBlob after this function it returns.
+**
+** This function fails with SQLITE_ERROR if any of the following are true:
+** <ul>
+**   <li> ^(Database zDb does not exist)^,
+**   <li> ^(Table zTable does not exist within database zDb)^,
+**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
+**   <li> ^(Column zColumn does not exist)^,
+**   <li> ^(Row iRow is not present in the table)^,
+**   <li> ^(The specified column of row iRow contains a value that is not
+**         a TEXT or BLOB value)^,
+**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
+**         constraint and the blob is being opened for read/write access)^,
+**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
+**         column zColumn is part of a [child key] definition and the blob is
+**         being opened for read/write access)^.
+** </ul>
+**
+** ^Unless it returns SQLITE_MISUSE, this function sets the
+** [database connection] error code and message accessible via
+** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
+**
+** A BLOB referenced by sqlite3_blob_open() may be read using the
+** [sqlite3_blob_read()] interface and modified by using
+** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
+** different row of the same table using the [sqlite3_blob_reopen()]
+** interface.  However, the column, table, or database of a [BLOB handle]
+** cannot be changed after the [BLOB handle] is opened.
+**
+** ^(If the row that a BLOB handle points to is modified by an
+** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
+** then the BLOB handle is marked as "expired".
+** This is true if any column of the row is changed, even a column
+** other than the one the BLOB handle is open on.)^
+** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
+** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
+** ^(Changes written into a BLOB prior to the BLOB expiring are not
+** rolled back by the expiration of the BLOB.  Such changes will eventually
+** commit if the transaction continues to completion.)^
+**
+** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
+** the opened blob.  ^The size of a blob may not be changed by this
+** interface.  Use the [UPDATE] SQL command to change the size of a
+** blob.
+**
+** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
+** and the built-in [zeroblob] SQL function may be used to create a
+** zero-filled blob to read or write using the incremental-blob interface.
+**
+** To avoid a resource leak, every open [BLOB handle] should eventually
+** be released by a call to [sqlite3_blob_close()].
+**
+** See also: [sqlite3_blob_close()],
+** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
+** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
+*/
+SQLITE_API int sqlite3_blob_open(
+  sqlite3*,
+  const char *zDb,
+  const char *zTable,
+  const char *zColumn,
+  sqlite3_int64 iRow,
+  int flags,
+  sqlite3_blob **ppBlob
+);
+
+/*
+** CAPI3REF: Move a BLOB Handle to a New Row
+** METHOD: sqlite3_blob
+**
+** ^This function is used to move an existing [BLOB handle] so that it points
+** to a different row of the same database table. ^The new row is identified
+** by the rowid value passed as the second argument. Only the row can be
+** changed. ^The database, table and column on which the blob handle is open
+** remain the same. Moving an existing [BLOB handle] to a new row is
+** faster than closing the existing handle and opening a new one.
+**
+** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
+** it must exist and there must be either a blob or text value stored in
+** the nominated column.)^ ^If the new row is not present in the table, or if
+** it does not contain a blob or text value, or if another error occurs, an
+** SQLite error code is returned and the blob handle is considered aborted.
+** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
+** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
+** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
+** always returns zero.
+**
+** ^This function sets the database handle error code and message.
+*/
+SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
+
+/*
+** CAPI3REF: Close A BLOB Handle
+** DESTRUCTOR: sqlite3_blob
+**
+** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
+** unconditionally.  Even if this routine returns an error code, the
+** handle is still closed.)^
+**
+** ^If the blob handle being closed was opened for read-write access, and if
+** the database is in auto-commit mode and there are no other open read-write
+** blob handles or active write statements, the current transaction is
+** committed. ^If an error occurs while committing the transaction, an error
+** code is returned and the transaction rolled back.
+**
+** Calling this function with an argument that is not a NULL pointer or an
+** open blob handle results in undefined behavior. ^Calling this routine
+** with a null pointer (such as would be returned by a failed call to
+** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
+** is passed a valid open blob handle, the values returned by the
+** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
+*/
+SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
+
+/*
+** CAPI3REF: Return The Size Of An Open BLOB
+** METHOD: sqlite3_blob
+**
+** ^Returns the size in bytes of the BLOB accessible via the
+** successfully opened [BLOB handle] in its only argument.  ^The
+** incremental blob I/O routines can only read or overwriting existing
+** blob content; they cannot change the size of a blob.
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+*/
+SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
+
+/*
+** CAPI3REF: Read Data From A BLOB Incrementally
+** METHOD: sqlite3_blob
+**
+** ^(This function is used to read data from an open [BLOB handle] into a
+** caller-supplied buffer. N bytes of data are copied into buffer Z
+** from the open BLOB, starting at offset iOffset.)^
+**
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
+** less than zero, [SQLITE_ERROR] is returned and no data is read.
+** ^The size of the blob (and hence the maximum value of N+iOffset)
+** can be determined using the [sqlite3_blob_bytes()] interface.
+**
+** ^An attempt to read from an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].
+**
+** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
+** Otherwise, an [error code] or an [extended error code] is returned.)^
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+**
+** See also: [sqlite3_blob_write()].
+*/
+SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
+
+/*
+** CAPI3REF: Write Data Into A BLOB Incrementally
+** METHOD: sqlite3_blob
+**
+** ^(This function is used to write data into an open [BLOB handle] from a
+** caller-supplied buffer. N bytes of data are copied from the buffer Z
+** into the open BLOB, starting at offset iOffset.)^
+**
+** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
+** Otherwise, an  [error code] or an [extended error code] is returned.)^
+** ^Unless SQLITE_MISUSE is returned, this function sets the
+** [database connection] error code and message accessible via
+** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
+**
+** ^If the [BLOB handle] passed as the first argument was not opened for
+** writing (the flags parameter to [sqlite3_blob_open()] was zero),
+** this function returns [SQLITE_READONLY].
+**
+** This function may only modify the contents of the BLOB; it is
+** not possible to increase the size of a BLOB using this API.
+** ^If offset iOffset is less than N bytes from the end of the BLOB,
+** [SQLITE_ERROR] is returned and no data is written. The size of the
+** BLOB (and hence the maximum value of N+iOffset) can be determined
+** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
+** than zero [SQLITE_ERROR] is returned and no data is written.
+**
+** ^An attempt to write to an expired [BLOB handle] fails with an
+** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
+** before the [BLOB handle] expired are not rolled back by the
+** expiration of the handle, though of course those changes might
+** have been overwritten by the statement that expired the BLOB handle
+** or by other independent statements.
+**
+** This routine only works on a [BLOB handle] which has been created
+** by a prior successful call to [sqlite3_blob_open()] and which has not
+** been closed by [sqlite3_blob_close()].  Passing any other pointer in
+** to this routine results in undefined and probably undesirable behavior.
+**
+** See also: [sqlite3_blob_read()].
+*/
+SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
+
+/*
+** CAPI3REF: Virtual File System Objects
+**
+** A virtual filesystem (VFS) is an [sqlite3_vfs] object
+** that SQLite uses to interact
+** with the underlying operating system.  Most SQLite builds come with a
+** single default VFS that is appropriate for the host computer.
+** New VFSes can be registered and existing VFSes can be unregistered.
+** The following interfaces are provided.
+**
+** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
+** ^Names are case sensitive.
+** ^Names are zero-terminated UTF-8 strings.
+** ^If there is no match, a NULL pointer is returned.
+** ^If zVfsName is NULL then the default VFS is returned.
+**
+** ^New VFSes are registered with sqlite3_vfs_register().
+** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
+** ^The same VFS can be registered multiple times without injury.
+** ^To make an existing VFS into the default VFS, register it again
+** with the makeDflt flag set.  If two different VFSes with the
+** same name are registered, the behavior is undefined.  If a
+** VFS is registered with a name that is NULL or an empty string,
+** then the behavior is undefined.
+**
+** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
+** ^(If the default VFS is unregistered, another VFS is chosen as
+** the default.  The choice for the new VFS is arbitrary.)^
+*/
+SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
+SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
+SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
+
+/*
+** CAPI3REF: Mutexes
+**
+** The SQLite core uses these routines for thread
+** synchronization. Though they are intended for internal
+** use by SQLite, code that links against SQLite is
+** permitted to use any of these routines.
+**
+** The SQLite source code contains multiple implementations
+** of these mutex routines.  An appropriate implementation
+** is selected automatically at compile-time.  The following
+** implementations are available in the SQLite core:
+**
+** <ul>
+** <li>   SQLITE_MUTEX_PTHREADS
+** <li>   SQLITE_MUTEX_W32
+** <li>   SQLITE_MUTEX_NOOP
+** </ul>
+**
+** The SQLITE_MUTEX_NOOP implementation is a set of routines
+** that does no real locking and is appropriate for use in
+** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
+** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
+** and Windows.
+**
+** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
+** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
+** implementation is included with the library. In this case the
+** application must supply a custom mutex implementation using the
+** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
+** before calling sqlite3_initialize() or any other public sqlite3_
+** function that calls sqlite3_initialize().
+**
+** ^The sqlite3_mutex_alloc() routine allocates a new
+** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
+** routine returns NULL if it is unable to allocate the requested
+** mutex.  The argument to sqlite3_mutex_alloc() must one of these
+** integer constants:
+**
+** <ul>
+** <li>  SQLITE_MUTEX_FAST
+** <li>  SQLITE_MUTEX_RECURSIVE
+** <li>  SQLITE_MUTEX_STATIC_MAIN
+** <li>  SQLITE_MUTEX_STATIC_MEM
+** <li>  SQLITE_MUTEX_STATIC_OPEN
+** <li>  SQLITE_MUTEX_STATIC_PRNG
+** <li>  SQLITE_MUTEX_STATIC_LRU
+** <li>  SQLITE_MUTEX_STATIC_PMEM
+** <li>  SQLITE_MUTEX_STATIC_APP1
+** <li>  SQLITE_MUTEX_STATIC_APP2
+** <li>  SQLITE_MUTEX_STATIC_APP3
+** <li>  SQLITE_MUTEX_STATIC_VFS1
+** <li>  SQLITE_MUTEX_STATIC_VFS2
+** <li>  SQLITE_MUTEX_STATIC_VFS3
+** </ul>
+**
+** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
+** cause sqlite3_mutex_alloc() to create
+** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
+** The mutex implementation does not need to make a distinction
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
+** not want to.  SQLite will only request a recursive mutex in
+** cases where it really needs one.  If a faster non-recursive mutex
+** implementation is available on the host platform, the mutex subsystem
+** might return such a mutex in response to SQLITE_MUTEX_FAST.
+**
+** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
+** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
+** a pointer to a static preexisting mutex.  ^Nine static mutexes are
+** used by the current version of SQLite.  Future versions of SQLite
+** may add additional static mutexes.  Static mutexes are for internal
+** use by SQLite only.  Applications that use SQLite mutexes should
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
+** SQLITE_MUTEX_RECURSIVE.
+**
+** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
+** returns a different mutex on every call.  ^For the static
+** mutex types, the same mutex is returned on every call that has
+** the same type number.
+**
+** ^The sqlite3_mutex_free() routine deallocates a previously
+** allocated dynamic mutex.  Attempting to deallocate a static
+** mutex results in undefined behavior.
+**
+** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
+** to enter a mutex.  ^If another thread is already within the mutex,
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
+** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
+** upon successful entry.  ^(Mutexes created using
+** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
+** In such cases, the
+** mutex must be exited an equal number of times before another thread
+** can enter.)^  If the same thread tries to enter any mutex other
+** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
+**
+** ^(Some systems (for example, Windows 95) do not support the operation
+** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
+** will always return SQLITE_BUSY. In most cases the SQLite core only uses
+** sqlite3_mutex_try() as an optimization, so this is acceptable
+** behavior. The exceptions are unix builds that set the
+** SQLITE_ENABLE_SETLK_TIMEOUT build option. In that case a working
+** sqlite3_mutex_try() is required.)^
+**
+** ^The sqlite3_mutex_leave() routine exits a mutex that was
+** previously entered by the same thread.   The behavior
+** is undefined if the mutex is not currently entered by the
+** calling thread or is not currently allocated.
+**
+** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(),
+** sqlite3_mutex_leave(), or sqlite3_mutex_free() is a NULL pointer,
+** then any of the four routines behaves as a no-op.
+**
+** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
+*/
+SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
+SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
+SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
+
+/*
+** CAPI3REF: Mutex Methods Object
+**
+** An instance of this structure defines the low-level routines
+** used to allocate and use mutexes.
+**
+** Usually, the default mutex implementations provided by SQLite are
+** sufficient, however the application has the option of substituting a custom
+** implementation for specialized deployments or systems for which SQLite
+** does not provide a suitable implementation. In this case, the application
+** creates and populates an instance of this structure to pass
+** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
+** Additionally, an instance of this structure can be used as an
+** output variable when querying the system for the current mutex
+** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
+**
+** ^The xMutexInit method defined by this structure is invoked as
+** part of system initialization by the sqlite3_initialize() function.
+** ^The xMutexInit routine is called by SQLite exactly once for each
+** effective call to [sqlite3_initialize()].
+**
+** ^The xMutexEnd method defined by this structure is invoked as
+** part of system shutdown by the sqlite3_shutdown() function. The
+** implementation of this method is expected to release all outstanding
+** resources obtained by the mutex methods implementation, especially
+** those obtained by the xMutexInit method.  ^The xMutexEnd()
+** interface is invoked exactly once for each call to [sqlite3_shutdown()].
+**
+** ^(The remaining seven methods defined by this structure (xMutexAlloc,
+** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
+** xMutexNotheld) implement the following interfaces (respectively):
+**
+** <ul>
+**   <li>  [sqlite3_mutex_alloc()] </li>
+**   <li>  [sqlite3_mutex_free()] </li>
+**   <li>  [sqlite3_mutex_enter()] </li>
+**   <li>  [sqlite3_mutex_try()] </li>
+**   <li>  [sqlite3_mutex_leave()] </li>
+**   <li>  [sqlite3_mutex_held()] </li>
+**   <li>  [sqlite3_mutex_notheld()] </li>
+** </ul>)^
+**
+** The only difference is that the public sqlite3_XXX functions enumerated
+** above silently ignore any invocations that pass a NULL pointer instead
+** of a valid mutex handle. The implementations of the methods defined
+** by this structure are not required to handle this case. The results
+** of passing a NULL pointer instead of a valid mutex handle are undefined
+** (i.e. it is acceptable to provide an implementation that segfaults if
+** it is passed a NULL pointer).
+**
+** The xMutexInit() method must be threadsafe.  It must be harmless to
+** invoke xMutexInit() multiple times within the same process and without
+** intervening calls to xMutexEnd().  Second and subsequent calls to
+** xMutexInit() must be no-ops.
+**
+** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
+** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
+** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
+** memory allocation for a fast or recursive mutex.
+**
+** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
+** called, but only if the prior call to xMutexInit returned SQLITE_OK.
+** If xMutexInit fails in any way, it is expected to clean up after itself
+** prior to returning.
+*/
+typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
+struct sqlite3_mutex_methods {
+  int (*xMutexInit)(void);
+  int (*xMutexEnd)(void);
+  sqlite3_mutex *(*xMutexAlloc)(int);
+  void (*xMutexFree)(sqlite3_mutex *);
+  void (*xMutexEnter)(sqlite3_mutex *);
+  int (*xMutexTry)(sqlite3_mutex *);
+  void (*xMutexLeave)(sqlite3_mutex *);
+  int (*xMutexHeld)(sqlite3_mutex *);
+  int (*xMutexNotheld)(sqlite3_mutex *);
+};
+
+/*
+** CAPI3REF: Mutex Verification Routines
+**
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
+** are intended for use inside assert() statements.  The SQLite core
+** never uses these routines except inside an assert() and applications
+** are advised to follow the lead of the core.  The SQLite core only
+** provides implementations for these routines when it is compiled
+** with the SQLITE_DEBUG flag.  External mutex implementations
+** are only required to provide these routines if SQLITE_DEBUG is
+** defined and if NDEBUG is not defined.
+**
+** These routines should return true if the mutex in their argument
+** is held or not held, respectively, by the calling thread.
+**
+** The implementation is not required to provide versions of these
+** routines that actually work. If the implementation does not provide working
+** versions of these routines, it should at least provide stubs that always
+** return true so that one does not get spurious assertion failures.
+**
+** If the argument to sqlite3_mutex_held() is a NULL pointer then
+** the routine should return 1.   This seems counter-intuitive since
+** clearly the mutex cannot be held if it does not exist.  But
+** the reason the mutex does not exist is because the build is not
+** using mutexes.  And we do not want the assert() containing the
+** call to sqlite3_mutex_held() to fail, so a non-zero return is
+** the appropriate thing to do.  The sqlite3_mutex_notheld()
+** interface should also return 1 when given a NULL pointer.
+*/
+#ifndef NDEBUG
+SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
+SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
+#endif
+
+/*
+** CAPI3REF: Mutex Types
+**
+** The [sqlite3_mutex_alloc()] interface takes a single argument
+** which is one of these integer constants.
+**
+** The set of static mutexes may change from one SQLite release to the
+** next.  Applications that override the built-in mutex logic must be
+** prepared to accommodate additional static mutexes.
+*/
+#define SQLITE_MUTEX_FAST             0
+#define SQLITE_MUTEX_RECURSIVE        1
+#define SQLITE_MUTEX_STATIC_MAIN      2
+#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
+#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
+#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
+#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
+#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
+#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
+#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
+#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
+#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
+#define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
+#define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
+#define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
+
+/* Legacy compatibility: */
+#define SQLITE_MUTEX_STATIC_MASTER    2
+
+
+/*
+** CAPI3REF: Retrieve the mutex for a database connection
+** METHOD: sqlite3
+**
+** ^This interface returns a pointer the [sqlite3_mutex] object that
+** serializes access to the [database connection] given in the argument
+** when the [threading mode] is Serialized.
+** ^If the [threading mode] is Single-thread or Multi-thread then this
+** routine returns a NULL pointer.
+*/
+SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
+
+/*
+** CAPI3REF: Low-Level Control Of Database Files
+** METHOD: sqlite3
+** KEYWORDS: {file control}
+**
+** ^The [sqlite3_file_control()] interface makes a direct call to the
+** xFileControl method for the [sqlite3_io_methods] object associated
+** with a particular database identified by the second argument. ^The
+** name of the database is "main" for the main database or "temp" for the
+** TEMP database, or the name that appears after the AS keyword for
+** databases that are added using the [ATTACH] SQL command.
+** ^A NULL pointer can be used in place of "main" to refer to the
+** main database file.
+** ^The third and fourth parameters to this routine
+** are passed directly through to the second and third parameters of
+** the xFileControl method.  ^The return value of the xFileControl
+** method becomes the return value of this routine.
+**
+** A few opcodes for [sqlite3_file_control()] are handled directly
+** by the SQLite core and never invoke the
+** sqlite3_io_methods.xFileControl method.
+** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
+** a pointer to the underlying [sqlite3_file] object to be written into
+** the space pointed to by the 4th parameter.  The
+** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
+** the [sqlite3_file] object associated with the journal file instead of
+** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
+** a pointer to the underlying [sqlite3_vfs] object for the file.
+** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
+** from the pager.
+**
+** ^If the second parameter (zDbName) does not match the name of any
+** open database file, then SQLITE_ERROR is returned.  ^This error
+** code is not remembered and will not be recalled by [sqlite3_errcode()]
+** or [sqlite3_errmsg()].  The underlying xFileControl method might
+** also return SQLITE_ERROR.  There is no way to distinguish between
+** an incorrect zDbName and an SQLITE_ERROR return from the underlying
+** xFileControl method.
+**
+** See also: [file control opcodes]
+*/
+SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
+
+/*
+** CAPI3REF: Testing Interface
+**
+** ^The sqlite3_test_control() interface is used to read out internal
+** state of SQLite and to inject faults into SQLite for testing
+** purposes.  ^The first parameter is an operation code that determines
+** the number, meaning, and operation of all subsequent parameters.
+**
+** This interface is not for use by applications.  It exists solely
+** for verifying the correct operation of the SQLite library.  Depending
+** on how the SQLite library is compiled, this interface might not exist.
+**
+** The details of the operation codes, their meanings, the parameters
+** they take, and what they do are all subject to change without notice.
+** Unlike most of the SQLite API, this function is not guaranteed to
+** operate consistently from one release to the next.
+*/
+SQLITE_API int sqlite3_test_control(int op, ...);
+
+/*
+** CAPI3REF: Testing Interface Operation Codes
+**
+** These constants are the valid operation code parameters used
+** as the first argument to [sqlite3_test_control()].
+**
+** These parameters and their meanings are subject to change
+** without notice.  These values are for testing purposes only.
+** Applications should not use any of these parameters or the
+** [sqlite3_test_control()] interface.
+*/
+#define SQLITE_TESTCTRL_FIRST                    5
+#define SQLITE_TESTCTRL_PRNG_SAVE                5
+#define SQLITE_TESTCTRL_PRNG_RESTORE             6
+#define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
+#define SQLITE_TESTCTRL_FK_NO_ACTION             7
+#define SQLITE_TESTCTRL_BITVEC_TEST              8
+#define SQLITE_TESTCTRL_FAULT_INSTALL            9
+#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
+#define SQLITE_TESTCTRL_PENDING_BYTE            11
+#define SQLITE_TESTCTRL_ASSERT                  12
+#define SQLITE_TESTCTRL_ALWAYS                  13
+#define SQLITE_TESTCTRL_RESERVE                 14  /* NOT USED */
+#define SQLITE_TESTCTRL_JSON_SELFCHECK          14
+#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
+#define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
+#define SQLITE_TESTCTRL_GETOPT                  16
+#define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
+#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
+#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
+#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
+#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
+#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
+#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
+#define SQLITE_TESTCTRL_BYTEORDER               22
+#define SQLITE_TESTCTRL_ISINIT                  23
+#define SQLITE_TESTCTRL_SORTER_MMAP             24
+#define SQLITE_TESTCTRL_IMPOSTER                25
+#define SQLITE_TESTCTRL_PARSER_COVERAGE         26
+#define SQLITE_TESTCTRL_RESULT_INTREAL          27
+#define SQLITE_TESTCTRL_PRNG_SEED               28
+#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
+#define SQLITE_TESTCTRL_SEEK_COUNT              30
+#define SQLITE_TESTCTRL_TRACEFLAGS              31
+#define SQLITE_TESTCTRL_TUNE                    32
+#define SQLITE_TESTCTRL_LOGEST                  33
+#define SQLITE_TESTCTRL_USELONGDOUBLE           34  /* NOT USED */
+#define SQLITE_TESTCTRL_LAST                    34  /* Largest TESTCTRL */
+
+/*
+** CAPI3REF: SQL Keyword Checking
+**
+** These routines provide access to the set of SQL language keywords
+** recognized by SQLite.  Applications can uses these routines to determine
+** whether or not a specific identifier needs to be escaped (for example,
+** by enclosing in double-quotes) so as not to confuse the parser.
+**
+** The sqlite3_keyword_count() interface returns the number of distinct
+** keywords understood by SQLite.
+**
+** The sqlite3_keyword_name(N,Z,L) interface finds the 0-based N-th keyword and
+** makes *Z point to that keyword expressed as UTF8 and writes the number
+** of bytes in the keyword into *L.  The string that *Z points to is not
+** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
+** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
+** or L are NULL or invalid pointers then calls to
+** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
+**
+** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
+** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
+** if it is and zero if not.
+**
+** The parser used by SQLite is forgiving.  It is often possible to use
+** a keyword as an identifier as long as such use does not result in a
+** parsing ambiguity.  For example, the statement
+** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
+** creates a new table named "BEGIN" with three columns named
+** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
+** using keywords as identifiers.  Common techniques used to avoid keyword
+** name collisions include:
+** <ul>
+** <li> Put all identifier names inside double-quotes.  This is the official
+**      SQL way to escape identifier names.
+** <li> Put identifier names inside [...].  This is not standard SQL,
+**      but it is what SQL Server does and so lots of programmers use this
+**      technique.
+** <li> Begin every identifier with the letter "Z" as no SQL keywords start
+**      with "Z".
+** <li> Include a digit somewhere in every identifier name.
+** </ul>
+**
+** Note that the number of keywords understood by SQLite can depend on
+** compile-time options.  For example, "VACUUM" is not a keyword if
+** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
+** new keywords may be added to future releases of SQLite.
+*/
+SQLITE_API int sqlite3_keyword_count(void);
+SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
+SQLITE_API int sqlite3_keyword_check(const char*,int);
+
+/*
+** CAPI3REF: Dynamic String Object
+** KEYWORDS: {dynamic string}
+**
+** An instance of the sqlite3_str object contains a dynamically-sized
+** string under construction.
+**
+** The lifecycle of an sqlite3_str object is as follows:
+** <ol>
+** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
+** <li> ^Text is appended to the sqlite3_str object using various
+** methods, such as [sqlite3_str_appendf()].
+** <li> ^The sqlite3_str object is destroyed and the string it created
+** is returned using the [sqlite3_str_finish()] interface.
+** </ol>
+*/
+typedef struct sqlite3_str sqlite3_str;
+
+/*
+** CAPI3REF: Create A New Dynamic String Object
+** CONSTRUCTOR: sqlite3_str
+**
+** ^The [sqlite3_str_new(D)] interface allocates and initializes
+** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
+** [sqlite3_str_new()] must be freed by a subsequent call to
+** [sqlite3_str_finish(X)].
+**
+** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
+** valid [sqlite3_str] object, though in the event of an out-of-memory
+** error the returned object might be a special singleton that will
+** silently reject new text, always return SQLITE_NOMEM from
+** [sqlite3_str_errcode()], always return 0 for
+** [sqlite3_str_length()], and always return NULL from
+** [sqlite3_str_finish(X)].  It is always safe to use the value
+** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
+** to any of the other [sqlite3_str] methods.
+**
+** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
+** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
+** length of the string contained in the [sqlite3_str] object will be
+** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
+** of [SQLITE_MAX_LENGTH].
+*/
+SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
+
+/*
+** CAPI3REF: Finalize A Dynamic String
+** DESTRUCTOR: sqlite3_str
+**
+** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
+** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
+** that contains the constructed string.  The calling application should
+** pass the returned value to [sqlite3_free()] to avoid a memory leak.
+** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
+** errors were encountered during construction of the string.  ^The
+** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
+** string in [sqlite3_str] object X is zero bytes long.
+*/
+SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
+
+/*
+** CAPI3REF: Add Content To A Dynamic String
+** METHOD: sqlite3_str
+**
+** These interfaces add content to an sqlite3_str object previously obtained
+** from [sqlite3_str_new()].
+**
+** ^The [sqlite3_str_appendf(X,F,...)] and
+** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
+** functionality of SQLite to append formatted text onto the end of
+** [sqlite3_str] object X.
+**
+** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
+** onto the end of the [sqlite3_str] object X.  N must be non-negative.
+** S must contain at least N non-zero bytes of content.  To append a
+** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
+** method instead.
+**
+** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
+** zero-terminated string S onto the end of [sqlite3_str] object X.
+**
+** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
+** single-byte character C onto the end of [sqlite3_str] object X.
+** ^This method can be used, for example, to add whitespace indentation.
+**
+** ^The [sqlite3_str_reset(X)] method resets the string under construction
+** inside [sqlite3_str] object X back to zero bytes in length.
+**
+** These methods do not return a result code.  ^If an error occurs, that fact
+** is recorded in the [sqlite3_str] object and can be recovered by a
+** subsequent call to [sqlite3_str_errcode(X)].
+*/
+SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
+SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
+SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
+SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
+SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
+SQLITE_API void sqlite3_str_reset(sqlite3_str*);
+
+/*
+** CAPI3REF: Status Of A Dynamic String
+** METHOD: sqlite3_str
+**
+** These interfaces return the current status of an [sqlite3_str] object.
+**
+** ^If any prior errors have occurred while constructing the dynamic string
+** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
+** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
+** [SQLITE_NOMEM] following any out-of-memory error, or
+** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
+** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
+**
+** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
+** of the dynamic string under construction in [sqlite3_str] object X.
+** ^The length returned by [sqlite3_str_length(X)] does not include the
+** zero-termination byte.
+**
+** ^The [sqlite3_str_value(X)] method returns a pointer to the current
+** content of the dynamic string under construction in X.  The value
+** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
+** and might be freed or altered by any subsequent method on the same
+** [sqlite3_str] object.  Applications must not used the pointer returned
+** [sqlite3_str_value(X)] after any subsequent method call on the same
+** object.  ^Applications may change the content of the string returned
+** by [sqlite3_str_value(X)] as long as they do not write into any bytes
+** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
+** write any byte after any subsequent sqlite3_str method call.
+*/
+SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
+SQLITE_API int sqlite3_str_length(sqlite3_str*);
+SQLITE_API char *sqlite3_str_value(sqlite3_str*);
+
+/*
+** CAPI3REF: SQLite Runtime Status
+**
+** ^These interfaces are used to retrieve runtime status information
+** about the performance of SQLite, and optionally to reset various
+** highwater marks.  ^The first argument is an integer code for
+** the specific parameter to measure.  ^(Recognized integer codes
+** are of the form [status parameters | SQLITE_STATUS_...].)^
+** ^The current value of the parameter is returned into *pCurrent.
+** ^The highest recorded value is returned in *pHighwater.  ^If the
+** resetFlag is true, then the highest record value is reset after
+** *pHighwater is written.  ^(Some parameters do not record the highest
+** value.  For those parameters
+** nothing is written into *pHighwater and the resetFlag is ignored.)^
+** ^(Other parameters record only the highwater mark and not the current
+** value.  For these latter parameters nothing is written into *pCurrent.)^
+**
+** ^The sqlite3_status() and sqlite3_status64() routines return
+** SQLITE_OK on success and a non-zero [error code] on failure.
+**
+** If either the current value or the highwater mark is too large to
+** be represented by a 32-bit integer, then the values returned by
+** sqlite3_status() are undefined.
+**
+** See also: [sqlite3_db_status()]
+*/
+SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
+SQLITE_API int sqlite3_status64(
+  int op,
+  sqlite3_int64 *pCurrent,
+  sqlite3_int64 *pHighwater,
+  int resetFlag
+);
+
+
+/*
+** CAPI3REF: Status Parameters
+** KEYWORDS: {status parameters}
+**
+** These integer constants designate various run-time status parameters
+** that can be returned by [sqlite3_status()].
+**
+** <dl>
+** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
+** <dd>This parameter is the current amount of memory checked out
+** using [sqlite3_malloc()], either directly or indirectly.  The
+** figure includes calls made to [sqlite3_malloc()] by the application
+** and internal memory usage by the SQLite library.  Auxiliary page-cache
+** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
+** this parameter.  The amount returned is the sum of the allocation
+** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
+**
+** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
+** <dd>This parameter records the largest memory allocation request
+** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
+** internal equivalents).  Only the value returned in the
+** *pHighwater parameter to [sqlite3_status()] is of interest.
+** The value written into the *pCurrent parameter is undefined.</dd>)^
+**
+** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
+** <dd>This parameter records the number of separate memory allocations
+** currently checked out.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
+** <dd>This parameter returns the number of pages used out of the
+** [pagecache memory allocator] that was configured using
+** [SQLITE_CONFIG_PAGECACHE].  The
+** value returned is in pages, not in bytes.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
+** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
+** <dd>This parameter returns the number of bytes of page cache
+** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
+** buffer and where forced to overflow to [sqlite3_malloc()].  The
+** returned value includes allocations that overflowed because they
+** where too large (they were larger than the "sz" parameter to
+** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
+** no space was left in the page cache.</dd>)^
+**
+** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
+** <dd>This parameter records the largest memory allocation request
+** handed to the [pagecache memory allocator].  Only the value returned in the
+** *pHighwater parameter to [sqlite3_status()] is of interest.
+** The value written into the *pCurrent parameter is undefined.</dd>)^
+**
+** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
+** <dd>No longer used.</dd>
+**
+** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
+** <dd>The *pHighwater parameter records the deepest parser stack.
+** The *pCurrent value is undefined.  The *pHighwater value is only
+** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
+** </dl>
+**
+** New status parameters may be added from time to time.
+*/
+#define SQLITE_STATUS_MEMORY_USED          0
+#define SQLITE_STATUS_PAGECACHE_USED       1
+#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
+#define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
+#define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
+#define SQLITE_STATUS_MALLOC_SIZE          5
+#define SQLITE_STATUS_PARSER_STACK         6
+#define SQLITE_STATUS_PAGECACHE_SIZE       7
+#define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
+#define SQLITE_STATUS_MALLOC_COUNT         9
+
+/*
+** CAPI3REF: Database Connection Status
+** METHOD: sqlite3
+**
+** ^This interface is used to retrieve runtime status information
+** about a single [database connection].  ^The first argument is the
+** database connection object to be interrogated.  ^The second argument
+** is an integer constant, taken from the set of
+** [SQLITE_DBSTATUS options], that
+** determines the parameter to interrogate.  The set of
+** [SQLITE_DBSTATUS options] is likely
+** to grow in future releases of SQLite.
+**
+** ^The current value of the requested parameter is written into *pCur
+** and the highest instantaneous value is written into *pHiwtr.  ^If
+** the resetFlg is true, then the highest instantaneous value is
+** reset back down to the current value.
+**
+** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
+** non-zero [error code] on failure.
+**
+** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
+*/
+SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
+
+/*
+** CAPI3REF: Status Parameters for database connections
+** KEYWORDS: {SQLITE_DBSTATUS options}
+**
+** These constants are the available integer "verbs" that can be passed as
+** the second argument to the [sqlite3_db_status()] interface.
+**
+** New verbs may be added in future releases of SQLite. Existing verbs
+** might be discontinued. Applications should check the return code from
+** [sqlite3_db_status()] to make sure that the call worked.
+** The [sqlite3_db_status()] interface will return a non-zero error code
+** if a discontinued or unsupported verb is invoked.
+**
+** <dl>
+** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
+** <dd>This parameter returns the number of lookaside memory slots currently
+** checked out.</dd>)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
+** <dd>This parameter returns the number of malloc attempts that were
+** satisfied using lookaside memory. Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to the amount of
+** memory requested being larger than the lookaside slot size.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
+** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
+** <dd>This parameter returns the number malloc attempts that might have
+** been satisfied using lookaside memory but failed due to all lookaside
+** memory already being in use.
+** Only the high-water value is meaningful;
+** the current value is always zero.)^
+**
+** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** memory used by all pager caches associated with the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
+** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
+** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
+** pager cache is shared between two or more connections the bytes of heap
+** memory used by that pager cache is divided evenly between the attached
+** connections.)^  In other words, if none of the pager caches associated
+** with the database connection are shared, this request returns the same
+** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
+** shared, the value returned by this call will be smaller than that returned
+** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
+** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
+**
+** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** memory used to store the schema for all databases associated
+** with the connection - main, temp, and any [ATTACH]-ed databases.)^
+** ^The full amount of memory used by the schemas is reported, even if the
+** schema memory is shared with other database connections due to
+** [shared cache mode] being enabled.
+** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
+**
+** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
+** <dd>This parameter returns the approximate number of bytes of heap
+** and lookaside memory used by all prepared statements associated with
+** the database connection.)^
+** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
+** <dd>This parameter returns the number of pager cache hits that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
+** <dd>This parameter returns the number of pager cache misses that have
+** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk. Specifically, the number of pages written to the
+** wal file in wal mode databases, or the number of pages written to the
+** database file in rollback mode databases. Any pages written as part of
+** transaction rollback or database recovery operations are not included.
+** If an IO or other error occurs while writing a page to disk, the effect
+** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
+** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
+** <dd>This parameter returns the number of dirty cache entries that have
+** been written to disk in the middle of a transaction due to the page
+** cache overflowing. Transactions are more efficient if they are written
+** to disk all at once. When pages spill mid-transaction, that introduces
+** additional overhead. This parameter can be used help identify
+** inefficiencies that can be resolved by increasing the cache size.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
+** <dd>This parameter returns zero for the current value if and only if
+** all foreign key constraints (deferred or immediate) have been
+** resolved.)^  ^The highwater mark is always 0.
+** </dd>
+** </dl>
+*/
+#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
+#define SQLITE_DBSTATUS_CACHE_USED           1
+#define SQLITE_DBSTATUS_SCHEMA_USED          2
+#define SQLITE_DBSTATUS_STMT_USED            3
+#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
+#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
+#define SQLITE_DBSTATUS_CACHE_HIT            7
+#define SQLITE_DBSTATUS_CACHE_MISS           8
+#define SQLITE_DBSTATUS_CACHE_WRITE          9
+#define SQLITE_DBSTATUS_DEFERRED_FKS        10
+#define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
+#define SQLITE_DBSTATUS_CACHE_SPILL         12
+#define SQLITE_DBSTATUS_MAX                 12   /* Largest defined DBSTATUS */
+
+
+/*
+** CAPI3REF: Prepared Statement Status
+** METHOD: sqlite3_stmt
+**
+** ^(Each prepared statement maintains various
+** [SQLITE_STMTSTATUS counters] that measure the number
+** of times it has performed specific operations.)^  These counters can
+** be used to monitor the performance characteristics of the prepared
+** statements.  For example, if the number of table steps greatly exceeds
+** the number of table searches or result rows, that would tend to indicate
+** that the prepared statement is using a full table scan rather than
+** an index.
+**
+** ^(This interface is used to retrieve and reset counter values from
+** a [prepared statement].  The first argument is the prepared statement
+** object to be interrogated.  The second argument
+** is an integer code for a specific [SQLITE_STMTSTATUS counter]
+** to be interrogated.)^
+** ^The current value of the requested counter is returned.
+** ^If the resetFlg is true, then the counter is reset to zero after this
+** interface call returns.
+**
+** See also: [sqlite3_status()] and [sqlite3_db_status()].
+*/
+SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
+
+/*
+** CAPI3REF: Status Parameters for prepared statements
+** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
+**
+** These preprocessor macros define integer codes that name counter
+** values associated with the [sqlite3_stmt_status()] interface.
+** The meanings of the various counters are as follows:
+**
+** <dl>
+** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
+** <dd>^This is the number of times that SQLite has stepped forward in
+** a table as part of a full table scan.  Large numbers for this counter
+** may indicate opportunities for performance improvement through
+** careful use of indices.</dd>
+**
+** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
+** <dd>^This is the number of sort operations that have occurred.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance through careful use of indices.</dd>
+**
+** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
+** <dd>^This is the number of rows inserted into transient indices that
+** were created automatically in order to help joins run faster.
+** A non-zero value in this counter may indicate an opportunity to
+** improvement performance by adding permanent indices that do not
+** need to be reinitialized each time the statement is run.</dd>
+**
+** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
+** <dd>^This is the number of virtual machine operations executed
+** by the prepared statement if that number is less than or equal
+** to 2147483647.  The number of virtual machine operations can be
+** used as a proxy for the total work done by the prepared statement.
+** If the number of virtual machine operations exceeds 2147483647
+** then the value returned by this statement status code is undefined.
+**
+** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
+** <dd>^This is the number of times that the prepare statement has been
+** automatically regenerated due to schema changes or changes to
+** [bound parameters] that might affect the query plan.
+**
+** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
+** <dd>^This is the number of times that the prepared statement has
+** been run.  A single "run" for the purposes of this counter is one
+** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
+** The counter is incremented on the first [sqlite3_step()] call of each
+** cycle.
+**
+** [[SQLITE_STMTSTATUS_FILTER_MISS]]
+** [[SQLITE_STMTSTATUS_FILTER HIT]]
+** <dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
+** SQLITE_STMTSTATUS_FILTER_MISS</dt>
+** <dd>^SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
+** step was bypassed because a Bloom filter returned not-found.  The
+** corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
+** times that the Bloom filter returned a find, and thus the join step
+** had to be processed as normal.
+**
+** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
+** <dd>^This is the approximate number of bytes of heap memory
+** used to store the prepared statement.  ^This value is not actually
+** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
+** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
+** </dd>
+** </dl>
+*/
+#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
+#define SQLITE_STMTSTATUS_SORT              2
+#define SQLITE_STMTSTATUS_AUTOINDEX         3
+#define SQLITE_STMTSTATUS_VM_STEP           4
+#define SQLITE_STMTSTATUS_REPREPARE         5
+#define SQLITE_STMTSTATUS_RUN               6
+#define SQLITE_STMTSTATUS_FILTER_MISS       7
+#define SQLITE_STMTSTATUS_FILTER_HIT        8
+#define SQLITE_STMTSTATUS_MEMUSED           99
+
+/*
+** CAPI3REF: Custom Page Cache Object
+**
+** The sqlite3_pcache type is opaque.  It is implemented by
+** the pluggable module.  The SQLite core has no knowledge of
+** its size or internal structure and never deals with the
+** sqlite3_pcache object except by holding and passing pointers
+** to the object.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache sqlite3_pcache;
+
+/*
+** CAPI3REF: Custom Page Cache Object
+**
+** The sqlite3_pcache_page object represents a single page in the
+** page cache.  The page cache will allocate instances of this
+** object.  Various methods of the page cache use pointers to instances
+** of this object as parameters or as their return value.
+**
+** See [sqlite3_pcache_methods2] for additional information.
+*/
+typedef struct sqlite3_pcache_page sqlite3_pcache_page;
+struct sqlite3_pcache_page {
+  void *pBuf;        /* The content of the page */
+  void *pExtra;      /* Extra information associated with the page */
+};
+
+/*
+** CAPI3REF: Application Defined Page Cache.
+** KEYWORDS: {page cache}
+**
+** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
+** register an alternative page cache implementation by passing in an
+** instance of the sqlite3_pcache_methods2 structure.)^
+** In many applications, most of the heap memory allocated by
+** SQLite is used for the page cache.
+** By implementing a
+** custom page cache using this API, an application can better control
+** the amount of memory consumed by SQLite, the way in which
+** that memory is allocated and released, and the policies used to
+** determine exactly which parts of a database file are cached and for
+** how long.
+**
+** The alternative page cache mechanism is an
+** extreme measure that is only needed by the most demanding applications.
+** The built-in page cache is recommended for most uses.
+**
+** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
+** internal buffer by SQLite within the call to [sqlite3_config].  Hence
+** the application may discard the parameter after the call to
+** [sqlite3_config()] returns.)^
+**
+** [[the xInit() page cache method]]
+** ^(The xInit() method is called once for each effective
+** call to [sqlite3_initialize()])^
+** (usually only once during the lifetime of the process). ^(The xInit()
+** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
+** The intent of the xInit() method is to set up global data structures
+** required by the custom page cache implementation.
+** ^(If the xInit() method is NULL, then the
+** built-in default page cache is used instead of the application defined
+** page cache.)^
+**
+** [[the xShutdown() page cache method]]
+** ^The xShutdown() method is called by [sqlite3_shutdown()].
+** It can be used to clean up
+** any outstanding resources before process shutdown, if required.
+** ^The xShutdown() method may be NULL.
+**
+** ^SQLite automatically serializes calls to the xInit method,
+** so the xInit method need not be threadsafe.  ^The
+** xShutdown method is only called from [sqlite3_shutdown()] so it does
+** not need to be threadsafe either.  All other methods must be threadsafe
+** in multithreaded applications.
+**
+** ^SQLite will never invoke xInit() more than once without an intervening
+** call to xShutdown().
+**
+** [[the xCreate() page cache methods]]
+** ^SQLite invokes the xCreate() method to construct a new cache instance.
+** SQLite will typically create one cache instance for each open database file,
+** though this is not guaranteed. ^The
+** first parameter, szPage, is the size in bytes of the pages that must
+** be allocated by the cache.  ^szPage will always a power of two.  ^The
+** second parameter szExtra is a number of bytes of extra storage
+** associated with each page cache entry.  ^The szExtra parameter will
+** a number less than 250.  SQLite will use the
+** extra szExtra bytes on each page to store metadata about the underlying
+** database page on disk.  The value passed into szExtra depends
+** on the SQLite version, the target platform, and how SQLite was compiled.
+** ^The third argument to xCreate(), bPurgeable, is true if the cache being
+** created will be used to cache database pages of a file stored on disk, or
+** false if it is used for an in-memory database. The cache implementation
+** does not have to do anything special based with the value of bPurgeable;
+** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
+** never invoke xUnpin() except to deliberately delete a page.
+** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
+** false will always have the "discard" flag set to true.
+** ^Hence, a cache created with bPurgeable false will
+** never contain any unpinned pages.
+**
+** [[the xCachesize() page cache method]]
+** ^(The xCachesize() method may be called at any time by SQLite to set the
+** suggested maximum cache-size (number of pages stored by) the cache
+** instance passed as the first argument. This is the value configured using
+** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
+** parameter, the implementation is not required to do anything with this
+** value; it is advisory only.
+**
+** [[the xPagecount() page cache methods]]
+** The xPagecount() method must return the number of pages currently
+** stored in the cache, both pinned and unpinned.
+**
+** [[the xFetch() page cache methods]]
+** The xFetch() method locates a page in the cache and returns a pointer to
+** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
+** The pBuf element of the returned sqlite3_pcache_page object will be a
+** pointer to a buffer of szPage bytes used to store the content of a
+** single database page.  The pExtra element of sqlite3_pcache_page will be
+** a pointer to the szExtra bytes of extra storage that SQLite has requested
+** for each entry in the page cache.
+**
+** The page to be fetched is determined by the key. ^The minimum key value
+** is 1.  After it has been retrieved using xFetch, the page is considered
+** to be "pinned".
+**
+** If the requested page is already in the page cache, then the page cache
+** implementation must return a pointer to the page buffer with its content
+** intact.  If the requested page is not already in the cache, then the
+** cache implementation should use the value of the createFlag
+** parameter to help it determined what action to take:
+**
+** <table border=1 width=85% align=center>
+** <tr><th> createFlag <th> Behavior when page is not already in cache
+** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
+** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
+**                 Otherwise return NULL.
+** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
+**                 NULL if allocating a new page is effectively impossible.
+** </table>
+**
+** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
+** will only use a createFlag of 2 after a prior call with a createFlag of 1
+** failed.)^  In between the xFetch() calls, SQLite may
+** attempt to unpin one or more cache pages by spilling the content of
+** pinned pages to disk and synching the operating system disk cache.
+**
+** [[the xUnpin() page cache method]]
+** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
+** as its second argument.  If the third parameter, discard, is non-zero,
+** then the page must be evicted from the cache.
+** ^If the discard parameter is
+** zero, then the page may be discarded or retained at the discretion of
+** page cache implementation. ^The page cache implementation
+** may choose to evict unpinned pages at any time.
+**
+** The cache must not perform any reference counting. A single
+** call to xUnpin() unpins the page regardless of the number of prior calls
+** to xFetch().
+**
+** [[the xRekey() page cache methods]]
+** The xRekey() method is used to change the key value associated with the
+** page passed as the second argument. If the cache
+** previously contains an entry associated with newKey, it must be
+** discarded. ^Any prior cache entry associated with newKey is guaranteed not
+** to be pinned.
+**
+** When SQLite calls the xTruncate() method, the cache must discard all
+** existing cache entries with page numbers (keys) greater than or equal
+** to the value of the iLimit parameter passed to xTruncate(). If any
+** of these pages are pinned, they are implicitly unpinned, meaning that
+** they can be safely discarded.
+**
+** [[the xDestroy() page cache method]]
+** ^The xDestroy() method is used to delete a cache allocated by xCreate().
+** All resources associated with the specified cache should be freed. ^After
+** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
+** handle invalid, and will not use it with any other sqlite3_pcache_methods2
+** functions.
+**
+** [[the xShrink() page cache method]]
+** ^SQLite invokes the xShrink() method when it wants the page cache to
+** free up as much of heap memory as possible.  The page cache implementation
+** is not obligated to free any memory, but well-behaved implementations should
+** do their best.
+*/
+typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
+struct sqlite3_pcache_methods2 {
+  int iVersion;
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
+  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
+      unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+  void (*xShrink)(sqlite3_pcache*);
+};
+
+/*
+** This is the obsolete pcache_methods object that has now been replaced
+** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
+** retained in the header file for backwards compatibility only.
+*/
+typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
+struct sqlite3_pcache_methods {
+  void *pArg;
+  int (*xInit)(void*);
+  void (*xShutdown)(void*);
+  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
+  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
+  int (*xPagecount)(sqlite3_pcache*);
+  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
+  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
+  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
+  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
+  void (*xDestroy)(sqlite3_pcache*);
+};
+
+
+/*
+** CAPI3REF: Online Backup Object
+**
+** The sqlite3_backup object records state information about an ongoing
+** online backup operation.  ^The sqlite3_backup object is created by
+** a call to [sqlite3_backup_init()] and is destroyed by a call to
+** [sqlite3_backup_finish()].
+**
+** See Also: [Using the SQLite Online Backup API]
+*/
+typedef struct sqlite3_backup sqlite3_backup;
+
+/*
+** CAPI3REF: Online Backup API.
+**
+** The backup API copies the content of one database into another.
+** It is useful either for creating backups of databases or
+** for copying in-memory databases to or from persistent files.
+**
+** See Also: [Using the SQLite Online Backup API]
+**
+** ^SQLite holds a write transaction open on the destination database file
+** for the duration of the backup operation.
+** ^The source database is read-locked only while it is being read;
+** it is not locked continuously for the entire backup operation.
+** ^Thus, the backup may be performed on a live source database without
+** preventing other database connections from
+** reading or writing to the source database while the backup is underway.
+**
+** ^(To perform a backup operation:
+**   <ol>
+**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
+**         backup,
+**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
+**         the data between the two databases, and finally
+**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
+**         associated with the backup operation.
+**   </ol>)^
+** There should be exactly one call to sqlite3_backup_finish() for each
+** successful call to sqlite3_backup_init().
+**
+** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
+**
+** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
+** [database connection] associated with the destination database
+** and the database name, respectively.
+** ^The database name is "main" for the main database, "temp" for the
+** temporary database, or the name specified after the AS keyword in
+** an [ATTACH] statement for an attached database.
+** ^The S and M arguments passed to
+** sqlite3_backup_init(D,N,S,M) identify the [database connection]
+** and database name of the source database, respectively.
+** ^The source and destination [database connections] (parameters S and D)
+** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
+** an error.
+**
+** ^A call to sqlite3_backup_init() will fail, returning NULL, if
+** there is already a read or read-write transaction open on the
+** destination database.
+**
+** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
+** returned and an error code and error message are stored in the
+** destination [database connection] D.
+** ^The error code and message for the failed call to sqlite3_backup_init()
+** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
+** [sqlite3_errmsg16()] functions.
+** ^A successful call to sqlite3_backup_init() returns a pointer to an
+** [sqlite3_backup] object.
+** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
+** sqlite3_backup_finish() functions to perform the specified backup
+** operation.
+**
+** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
+**
+** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
+** the source and destination databases specified by [sqlite3_backup] object B.
+** ^If N is negative, all remaining source pages are copied.
+** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
+** are still more pages to be copied, then the function returns [SQLITE_OK].
+** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
+** from source to destination, then it returns [SQLITE_DONE].
+** ^If an error occurs while running sqlite3_backup_step(B,N),
+** then an [error code] is returned. ^As well as [SQLITE_OK] and
+** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
+** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
+**
+** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
+** <ol>
+** <li> the destination database was opened read-only, or
+** <li> the destination database is using write-ahead-log journaling
+** and the destination and source page sizes differ, or
+** <li> the destination database is an in-memory database and the
+** destination and source page sizes differ.
+** </ol>)^
+**
+** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
+** the [sqlite3_busy_handler | busy-handler function]
+** is invoked (if one is specified). ^If the
+** busy-handler returns non-zero before the lock is available, then
+** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
+** sqlite3_backup_step() can be retried later. ^If the source
+** [database connection]
+** is being used to write to the source database when sqlite3_backup_step()
+** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
+** case the call to sqlite3_backup_step() can be retried later on. ^(If
+** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
+** [SQLITE_READONLY] is returned, then
+** there is no point in retrying the call to sqlite3_backup_step(). These
+** errors are considered fatal.)^  The application must accept
+** that the backup operation has failed and pass the backup operation handle
+** to the sqlite3_backup_finish() to release associated resources.
+**
+** ^The first call to sqlite3_backup_step() obtains an exclusive lock
+** on the destination file. ^The exclusive lock is not released until either
+** sqlite3_backup_finish() is called or the backup operation is complete
+** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
+** sqlite3_backup_step() obtains a [shared lock] on the source database that
+** lasts for the duration of the sqlite3_backup_step() call.
+** ^Because the source database is not locked between calls to
+** sqlite3_backup_step(), the source database may be modified mid-way
+** through the backup process.  ^If the source database is modified by an
+** external process or via a database connection other than the one being
+** used by the backup operation, then the backup will be automatically
+** restarted by the next call to sqlite3_backup_step(). ^If the source
+** database is modified by the using the same database connection as is used
+** by the backup operation, then the backup database is automatically
+** updated at the same time.
+**
+** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
+**
+** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
+** application wishes to abandon the backup operation, the application
+** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
+** ^The sqlite3_backup_finish() interfaces releases all
+** resources associated with the [sqlite3_backup] object.
+** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
+** active write-transaction on the destination database is rolled back.
+** The [sqlite3_backup] object is invalid
+** and may not be used following a call to sqlite3_backup_finish().
+**
+** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
+** sqlite3_backup_step() errors occurred, regardless or whether or not
+** sqlite3_backup_step() completed.
+** ^If an out-of-memory condition or IO error occurred during any prior
+** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
+** sqlite3_backup_finish() returns the corresponding [error code].
+**
+** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
+** is not a permanent error and does not affect the return value of
+** sqlite3_backup_finish().
+**
+** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
+** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
+**
+** ^The sqlite3_backup_remaining() routine returns the number of pages still
+** to be backed up at the conclusion of the most recent sqlite3_backup_step().
+** ^The sqlite3_backup_pagecount() routine returns the total number of pages
+** in the source database at the conclusion of the most recent
+** sqlite3_backup_step().
+** ^(The values returned by these functions are only updated by
+** sqlite3_backup_step(). If the source database is modified in a way that
+** changes the size of the source database or the number of pages remaining,
+** those changes are not reflected in the output of sqlite3_backup_pagecount()
+** and sqlite3_backup_remaining() until after the next
+** sqlite3_backup_step().)^
+**
+** <b>Concurrent Usage of Database Handles</b>
+**
+** ^The source [database connection] may be used by the application for other
+** purposes while a backup operation is underway or being initialized.
+** ^If SQLite is compiled and configured to support threadsafe database
+** connections, then the source database connection may be used concurrently
+** from within other threads.
+**
+** However, the application must guarantee that the destination
+** [database connection] is not passed to any other API (by any thread) after
+** sqlite3_backup_init() is called and before the corresponding call to
+** sqlite3_backup_finish().  SQLite does not currently check to see
+** if the application incorrectly accesses the destination [database connection]
+** and so no error code is reported, but the operations may malfunction
+** nevertheless.  Use of the destination database connection while a
+** backup is in progress might also cause a mutex deadlock.
+**
+** If running in [shared cache mode], the application must
+** guarantee that the shared cache used by the destination database
+** is not accessed while the backup is running. In practice this means
+** that the application must guarantee that the disk file being
+** backed up to is not accessed by any connection within the process,
+** not just the specific connection that was passed to sqlite3_backup_init().
+**
+** The [sqlite3_backup] object itself is partially threadsafe. Multiple
+** threads may safely make multiple concurrent calls to sqlite3_backup_step().
+** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
+** APIs are not strictly speaking threadsafe. If they are invoked at the
+** same time as another thread is invoking sqlite3_backup_step() it is
+** possible that they return invalid values.
+**
+** <b>Alternatives To Using The Backup API</b>
+**
+** Other techniques for safely creating a consistent backup of an SQLite
+** database include:
+**
+** <ul>
+** <li> The [VACUUM INTO] command.
+** <li> The [sqlite3_rsync] utility program.
+** </ul>
+*/
+SQLITE_API sqlite3_backup *sqlite3_backup_init(
+  sqlite3 *pDest,                        /* Destination database handle */
+  const char *zDestName,                 /* Destination database name */
+  sqlite3 *pSource,                      /* Source database handle */
+  const char *zSourceName                /* Source database name */
+);
+SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
+SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
+SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
+
+/*
+** CAPI3REF: Unlock Notification
+** METHOD: sqlite3
+**
+** ^When running in shared-cache mode, a database operation may fail with
+** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
+** individual tables within the shared-cache cannot be obtained. See
+** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
+** ^This API may be used to register a callback that SQLite will invoke
+** when the connection currently holding the required lock relinquishes it.
+** ^This API is only available if the library was compiled with the
+** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
+**
+** See Also: [Using the SQLite Unlock Notification Feature].
+**
+** ^Shared-cache locks are released when a database connection concludes
+** its current transaction, either by committing it or rolling it back.
+**
+** ^When a connection (known as the blocked connection) fails to obtain a
+** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
+** identity of the database connection (the blocking connection) that
+** has locked the required resource is stored internally. ^After an
+** application receives an SQLITE_LOCKED error, it may call the
+** sqlite3_unlock_notify() method with the blocked connection handle as
+** the first argument to register for a callback that will be invoked
+** when the blocking connections current transaction is concluded. ^The
+** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
+** call that concludes the blocking connection's transaction.
+**
+** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
+** there is a chance that the blocking connection will have already
+** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
+** If this happens, then the specified callback is invoked immediately,
+** from within the call to sqlite3_unlock_notify().)^
+**
+** ^If the blocked connection is attempting to obtain a write-lock on a
+** shared-cache table, and more than one other connection currently holds
+** a read-lock on the same table, then SQLite arbitrarily selects one of
+** the other connections to use as the blocking connection.
+**
+** ^(There may be at most one unlock-notify callback registered by a
+** blocked connection. If sqlite3_unlock_notify() is called when the
+** blocked connection already has a registered unlock-notify callback,
+** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
+** called with a NULL pointer as its second argument, then any existing
+** unlock-notify callback is canceled. ^The blocked connections
+** unlock-notify callback may also be canceled by closing the blocked
+** connection using [sqlite3_close()].
+**
+** The unlock-notify callback is not reentrant. If an application invokes
+** any sqlite3_xxx API functions from within an unlock-notify callback, a
+** crash or deadlock may be the result.
+**
+** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
+** returns SQLITE_OK.
+**
+** <b>Callback Invocation Details</b>
+**
+** When an unlock-notify callback is registered, the application provides a
+** single void* pointer that is passed to the callback when it is invoked.
+** However, the signature of the callback function allows SQLite to pass
+** it an array of void* context pointers. The first argument passed to
+** an unlock-notify callback is a pointer to an array of void* pointers,
+** and the second is the number of entries in the array.
+**
+** When a blocking connection's transaction is concluded, there may be
+** more than one blocked connection that has registered for an unlock-notify
+** callback. ^If two or more such blocked connections have specified the
+** same callback function, then instead of invoking the callback function
+** multiple times, it is invoked once with the set of void* context pointers
+** specified by the blocked connections bundled together into an array.
+** This gives the application an opportunity to prioritize any actions
+** related to the set of unblocked database connections.
+**
+** <b>Deadlock Detection</b>
+**
+** Assuming that after registering for an unlock-notify callback a
+** database waits for the callback to be issued before taking any further
+** action (a reasonable assumption), then using this API may cause the
+** application to deadlock. For example, if connection X is waiting for
+** connection Y's transaction to be concluded, and similarly connection
+** Y is waiting on connection X's transaction, then neither connection
+** will proceed and the system may remain deadlocked indefinitely.
+**
+** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
+** detection. ^If a given call to sqlite3_unlock_notify() would put the
+** system in a deadlocked state, then SQLITE_LOCKED is returned and no
+** unlock-notify callback is registered. The system is said to be in
+** a deadlocked state if connection A has registered for an unlock-notify
+** callback on the conclusion of connection B's transaction, and connection
+** B has itself registered for an unlock-notify callback when connection
+** A's transaction is concluded. ^Indirect deadlock is also detected, so
+** the system is also considered to be deadlocked if connection B has
+** registered for an unlock-notify callback on the conclusion of connection
+** C's transaction, where connection C is waiting on connection A. ^Any
+** number of levels of indirection are allowed.
+**
+** <b>The "DROP TABLE" Exception</b>
+**
+** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
+** always appropriate to call sqlite3_unlock_notify(). There is however,
+** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
+** SQLite checks if there are any currently executing SELECT statements
+** that belong to the same connection. If there are, SQLITE_LOCKED is
+** returned. In this case there is no "blocking connection", so invoking
+** sqlite3_unlock_notify() results in the unlock-notify callback being
+** invoked immediately. If the application then re-attempts the "DROP TABLE"
+** or "DROP INDEX" query, an infinite loop might be the result.
+**
+** One way around this problem is to check the extended error code returned
+** by an sqlite3_step() call. ^(If there is a blocking connection, then the
+** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
+** the special "DROP TABLE/INDEX" case, the extended error code is just
+** SQLITE_LOCKED.)^
+*/
+SQLITE_API int sqlite3_unlock_notify(
+  sqlite3 *pBlocked,                          /* Waiting connection */
+  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
+  void *pNotifyArg                            /* Argument to pass to xNotify */
+);
+
+
+/*
+** CAPI3REF: String Comparison
+**
+** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
+** and extensions to compare the contents of two buffers containing UTF-8
+** strings in a case-independent fashion, using the same definition of "case
+** independence" that SQLite uses internally when comparing identifiers.
+*/
+SQLITE_API int sqlite3_stricmp(const char *, const char *);
+SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
+
+/*
+** CAPI3REF: String Globbing
+*
+** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
+** string X matches the [GLOB] pattern P.
+** ^The definition of [GLOB] pattern matching used in
+** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
+** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
+** is case sensitive.
+**
+** Note that this routine returns zero on a match and non-zero if the strings
+** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
+**
+** See also: [sqlite3_strlike()].
+*/
+SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
+
+/*
+** CAPI3REF: String LIKE Matching
+*
+** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
+** string X matches the [LIKE] pattern P with escape character E.
+** ^The definition of [LIKE] pattern matching used in
+** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
+** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
+** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
+** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
+** insensitive - equivalent upper and lower case ASCII characters match
+** one another.
+**
+** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
+** only ASCII characters are case folded.
+**
+** Note that this routine returns zero on a match and non-zero if the strings
+** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
+**
+** See also: [sqlite3_strglob()].
+*/
+SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
+
+/*
+** CAPI3REF: Error Logging Interface
+**
+** ^The [sqlite3_log()] interface writes a message into the [error log]
+** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
+** ^If logging is enabled, the zFormat string and subsequent arguments are
+** used with [sqlite3_snprintf()] to generate the final output string.
+**
+** The sqlite3_log() interface is intended for use by extensions such as
+** virtual tables, collating functions, and SQL functions.  While there is
+** nothing to prevent an application from calling sqlite3_log(), doing so
+** is considered bad form.
+**
+** The zFormat string must not be NULL.
+**
+** To avoid deadlocks and other threading problems, the sqlite3_log() routine
+** will not use dynamically allocated memory.  The log message is stored in
+** a fixed-length buffer on the stack.  If the log message is longer than
+** a few hundred characters, it will be truncated to the length of the
+** buffer.
+*/
+SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
+
+/*
+** CAPI3REF: Write-Ahead Log Commit Hook
+** METHOD: sqlite3
+**
+** ^The [sqlite3_wal_hook()] function is used to register a callback that
+** is invoked each time data is committed to a database in wal mode.
+**
+** ^(The callback is invoked by SQLite after the commit has taken place and
+** the associated write-lock on the database released)^, so the implementation
+** may read, write or [checkpoint] the database as required.
+**
+** ^The first parameter passed to the callback function when it is invoked
+** is a copy of the third parameter passed to sqlite3_wal_hook() when
+** registering the callback. ^The second is a copy of the database handle.
+** ^The third parameter is the name of the database that was written to -
+** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
+** is the number of pages currently in the write-ahead log file,
+** including those that were just committed.
+**
+** The callback function should normally return [SQLITE_OK].  ^If an error
+** code is returned, that error will propagate back up through the
+** SQLite code base to cause the statement that provoked the callback
+** to report an error, though the commit will have still occurred. If the
+** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
+** that does not correspond to any valid SQLite error code, the results
+** are undefined.
+**
+** A single database handle may have at most a single write-ahead log callback
+** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
+** previously registered write-ahead log callback. ^The return value is
+** a copy of the third parameter from the previous call, if any, or 0.
+** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
+** overwrite any prior [sqlite3_wal_hook()] settings.
+*/
+SQLITE_API void *sqlite3_wal_hook(
+  sqlite3*,
+  int(*)(void *,sqlite3*,const char*,int),
+  void*
+);
+
+/*
+** CAPI3REF: Configure an auto-checkpoint
+** METHOD: sqlite3
+**
+** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
+** [sqlite3_wal_hook()] that causes any database on [database connection] D
+** to automatically [checkpoint]
+** after committing a transaction if there are N or
+** more frames in the [write-ahead log] file.  ^Passing zero or
+** a negative value as the nFrame parameter disables automatic
+** checkpoints entirely.
+**
+** ^The callback registered by this function replaces any existing callback
+** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
+** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
+** configured by this function.
+**
+** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
+** from SQL.
+**
+** ^Checkpoints initiated by this mechanism are
+** [sqlite3_wal_checkpoint_v2|PASSIVE].
+**
+** ^Every new [database connection] defaults to having the auto-checkpoint
+** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
+** pages.  The use of this interface
+** is only necessary if the default setting is found to be suboptimal
+** for a particular application.
+*/
+SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
+
+/*
+** CAPI3REF: Checkpoint a database
+** METHOD: sqlite3
+**
+** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
+** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
+**
+** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
+** [write-ahead log] for database X on [database connection] D to be
+** transferred into the database file and for the write-ahead log to
+** be reset.  See the [checkpointing] documentation for addition
+** information.
+**
+** This interface used to be the only way to cause a checkpoint to
+** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
+** interface was added.  This interface is retained for backwards
+** compatibility and as a convenience for applications that need to manually
+** start a callback but which do not need the full power (and corresponding
+** complication) of [sqlite3_wal_checkpoint_v2()].
+*/
+SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Checkpoint a database
+** METHOD: sqlite3
+**
+** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
+** operation on database X of [database connection] D in mode M.  Status
+** information is written back into integers pointed to by L and C.)^
+** ^(The M parameter must be a valid [checkpoint mode]:)^
+**
+** <dl>
+** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
+**   ^Checkpoint as many frames as possible without waiting for any database
+**   readers or writers to finish, then sync the database file if all frames
+**   in the log were checkpointed. ^The [busy-handler callback]
+**   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
+**   ^On the other hand, passive mode might leave the checkpoint unfinished
+**   if there are concurrent readers or writers.
+**
+** <dt>SQLITE_CHECKPOINT_FULL<dd>
+**   ^This mode blocks (it invokes the
+**   [sqlite3_busy_handler|busy-handler callback]) until there is no
+**   database writer and all readers are reading from the most recent database
+**   snapshot. ^It then checkpoints all frames in the log file and syncs the
+**   database file. ^This mode blocks new database writers while it is pending,
+**   but new database readers are allowed to continue unimpeded.
+**
+** <dt>SQLITE_CHECKPOINT_RESTART<dd>
+**   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
+**   that after checkpointing the log file it blocks (calls the
+**   [busy-handler callback])
+**   until all readers are reading from the database file only. ^This ensures
+**   that the next writer will restart the log file from the beginning.
+**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
+**   database writer attempts while it is pending, but does not impede readers.
+**
+** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
+**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
+**   addition that it also truncates the log file to zero bytes just prior
+**   to a successful return.
+** </dl>
+**
+** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
+** the log file or to -1 if the checkpoint could not run because
+** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
+** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
+** log file (including any that were already checkpointed before the function
+** was called) or to -1 if the checkpoint could not run due to an error or
+** because the database is not in WAL mode. ^Note that upon successful
+** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
+** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
+**
+** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
+** any other process is running a checkpoint operation at the same time, the
+** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
+** busy-handler configured, it will not be invoked in this case.
+**
+** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
+** exclusive "writer" lock on the database file. ^If the writer lock cannot be
+** obtained immediately, and a busy-handler is configured, it is invoked and
+** the writer lock retried until either the busy-handler returns 0 or the lock
+** is successfully obtained. ^The busy-handler is also invoked while waiting for
+** database readers as described above. ^If the busy-handler returns 0 before
+** the writer lock is obtained or while waiting for database readers, the
+** checkpoint operation proceeds from that point in the same way as
+** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
+** without blocking any further. ^SQLITE_BUSY is returned in this case.
+**
+** ^If parameter zDb is NULL or points to a zero length string, then the
+** specified operation is attempted on all WAL databases [attached] to
+** [database connection] db.  In this case the
+** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
+** an SQLITE_BUSY error is encountered when processing one or more of the
+** attached WAL databases, the operation is still attempted on any remaining
+** attached databases and SQLITE_BUSY is returned at the end. ^If any other
+** error occurs while processing an attached database, processing is abandoned
+** and the error code is returned to the caller immediately. ^If no error
+** (SQLITE_BUSY or otherwise) is encountered while processing the attached
+** databases, SQLITE_OK is returned.
+**
+** ^If database zDb is the name of an attached database that is not in WAL
+** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
+** zDb is not NULL (or a zero length string) and is not the name of any
+** attached database, SQLITE_ERROR is returned to the caller.
+**
+** ^Unless it returns SQLITE_MISUSE,
+** the sqlite3_wal_checkpoint_v2() interface
+** sets the error information that is queried by
+** [sqlite3_errcode()] and [sqlite3_errmsg()].
+**
+** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
+** from SQL.
+*/
+SQLITE_API int sqlite3_wal_checkpoint_v2(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of attached database (or NULL) */
+  int eMode,                      /* SQLITE_CHECKPOINT_* value */
+  int *pnLog,                     /* OUT: Size of WAL log in frames */
+  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
+);
+
+/*
+** CAPI3REF: Checkpoint Mode Values
+** KEYWORDS: {checkpoint mode}
+**
+** These constants define all valid values for the "checkpoint mode" passed
+** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
+** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
+** meaning of each of these checkpoint modes.
+*/
+#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
+#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
+#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for readers */
+#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
+
+/*
+** CAPI3REF: Virtual Table Interface Configuration
+**
+** This function may be called by either the [xConnect] or [xCreate] method
+** of a [virtual table] implementation to configure
+** various facets of the virtual table interface.
+**
+** If this interface is invoked outside the context of an xConnect or
+** xCreate virtual table method then the behavior is undefined.
+**
+** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
+** [database connection] in which the virtual table is being created and
+** which is passed in as the first argument to the [xConnect] or [xCreate]
+** method that is invoking sqlite3_vtab_config().  The C parameter is one
+** of the [virtual table configuration options].  The presence and meaning
+** of parameters after C depend on which [virtual table configuration option]
+** is used.
+*/
+SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
+
+/*
+** CAPI3REF: Virtual Table Configuration Options
+** KEYWORDS: {virtual table configuration options}
+** KEYWORDS: {virtual table configuration option}
+**
+** These macros define the various options to the
+** [sqlite3_vtab_config()] interface that [virtual table] implementations
+** can use to customize and optimize their behavior.
+**
+** <dl>
+** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
+** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
+** where X is an integer.  If X is zero, then the [virtual table] whose
+** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
+** support constraints.  In this configuration (which is the default) if
+** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
+** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
+** specified as part of the users SQL statement, regardless of the actual
+** ON CONFLICT mode specified.
+**
+** If X is non-zero, then the virtual table implementation guarantees
+** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
+** any modifications to internal or persistent data structures have been made.
+** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
+** is able to roll back a statement or database transaction, and abandon
+** or continue processing the current SQL statement as appropriate.
+** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
+** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
+** had been ABORT.
+**
+** Virtual table implementations that are required to handle OR REPLACE
+** must do so within the [xUpdate] method. If a call to the
+** [sqlite3_vtab_on_conflict()] function indicates that the current ON
+** CONFLICT policy is REPLACE, the virtual table implementation should
+** silently replace the appropriate rows within the xUpdate callback and
+** return SQLITE_OK. Or, if this is not possible, it may return
+** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
+** constraint handling.
+** </dd>
+**
+** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** prohibits that virtual table from being used from within triggers and
+** views.
+** </dd>
+**
+** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** identify that virtual table as being safe to use from within triggers
+** and views.  Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
+** virtual table can do no serious harm even if it is controlled by a
+** malicious hacker.  Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
+** flag unless absolutely necessary.
+** </dd>
+**
+** [[SQLITE_VTAB_USES_ALL_SCHEMAS]]<dt>SQLITE_VTAB_USES_ALL_SCHEMAS</dt>
+** <dd>Calls of the form
+** [sqlite3_vtab_config](db,SQLITE_VTAB_USES_ALL_SCHEMA) from within the
+** the [xConnect] or [xCreate] methods of a [virtual table] implementation
+** instruct the query planner to begin at least a read transaction on
+** all schemas ("main", "temp", and any ATTACH-ed databases) whenever the
+** virtual table is used.
+** </dd>
+** </dl>
+*/
+#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
+#define SQLITE_VTAB_INNOCUOUS          2
+#define SQLITE_VTAB_DIRECTONLY         3
+#define SQLITE_VTAB_USES_ALL_SCHEMAS   4
+
+/*
+** CAPI3REF: Determine The Virtual Table Conflict Policy
+**
+** This function may only be called from within a call to the [xUpdate] method
+** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
+** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
+** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
+** of the SQL statement that triggered the call to the [xUpdate] method of the
+** [virtual table].
+*/
+SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
+
+/*
+** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
+**
+** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
+** method of a [virtual table], then it might return true if the
+** column is being fetched as part of an UPDATE operation during which the
+** column value will not change.  The virtual table implementation can use
+** this hint as permission to substitute a return value that is less
+** expensive to compute and that the corresponding
+** [xUpdate] method understands as a "no-change" value.
+**
+** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
+** the column is not changed by the UPDATE statement, then the xColumn
+** method can optionally return without setting a result, without calling
+** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
+** In that case, [sqlite3_value_nochange(X)] will return true for the
+** same column in the [xUpdate] method.
+**
+** The sqlite3_vtab_nochange() routine is an optimization.  Virtual table
+** implementations should continue to give a correct answer even if the
+** sqlite3_vtab_nochange() interface were to always return false.  In the
+** current implementation, the sqlite3_vtab_nochange() interface does always
+** returns false for the enhanced [UPDATE FROM] statement.
+*/
+SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
+
+/*
+** CAPI3REF: Determine The Collation For a Virtual Table Constraint
+** METHOD: sqlite3_index_info
+**
+** This function may only be called from within a call to the [xBestIndex]
+** method of a [virtual table].  This function returns a pointer to a string
+** that is the name of the appropriate collation sequence to use for text
+** comparisons on the constraint identified by its arguments.
+**
+** The first argument must be the pointer to the [sqlite3_index_info] object
+** that is the first parameter to the xBestIndex() method. The second argument
+** must be an index into the aConstraint[] array belonging to the
+** sqlite3_index_info structure passed to xBestIndex.
+**
+** Important:
+** The first parameter must be the same pointer that is passed into the
+** xBestMethod() method.  The first parameter may not be a pointer to a
+** different [sqlite3_index_info] object, even an exact copy.
+**
+** The return value is computed as follows:
+**
+** <ol>
+** <li><p> If the constraint comes from a WHERE clause expression that contains
+**         a [COLLATE operator], then the name of the collation specified by
+**         that COLLATE operator is returned.
+** <li><p> If there is no COLLATE operator, but the column that is the subject
+**         of the constraint specifies an alternative collating sequence via
+**         a [COLLATE clause] on the column definition within the CREATE TABLE
+**         statement that was passed into [sqlite3_declare_vtab()], then the
+**         name of that alternative collating sequence is returned.
+** <li><p> Otherwise, "BINARY" is returned.
+** </ol>
+*/
+SQLITE_API const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
+
+/*
+** CAPI3REF: Determine if a virtual table query is DISTINCT
+** METHOD: sqlite3_index_info
+**
+** This API may only be used from within an [xBestIndex|xBestIndex method]
+** of a [virtual table] implementation. The result of calling this
+** interface from outside of xBestIndex() is undefined and probably harmful.
+**
+** ^The sqlite3_vtab_distinct() interface returns an integer between 0 and
+** 3.  The integer returned by sqlite3_vtab_distinct()
+** gives the virtual table additional information about how the query
+** planner wants the output to be ordered. As long as the virtual table
+** can meet the ordering requirements of the query planner, it may set
+** the "orderByConsumed" flag.
+**
+** <ol><li value="0"><p>
+** ^If the sqlite3_vtab_distinct() interface returns 0, that means
+** that the query planner needs the virtual table to return all rows in the
+** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
+** [sqlite3_index_info] object.  This is the default expectation.  If the
+** virtual table outputs all rows in sorted order, then it is always safe for
+** the xBestIndex method to set the "orderByConsumed" flag, regardless of
+** the return value from sqlite3_vtab_distinct().
+** <li value="1"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
+** that the query planner does not need the rows to be returned in sorted order
+** as long as all rows with the same values in all columns identified by the
+** "aOrderBy" field are adjacent.)^  This mode is used when the query planner
+** is doing a GROUP BY.
+** <li value="2"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
+** that the query planner does not need the rows returned in any particular
+** order, as long as rows with the same values in all columns identified
+** by "aOrderBy" are adjacent.)^  ^(Furthermore, when two or more rows
+** contain the same values for all columns identified by "colUsed", all but
+** one such row may optionally be omitted from the result.)^
+** The virtual table is not required to omit rows that are duplicates
+** over the "colUsed" columns, but if the virtual table can do that without
+** too much extra effort, it could potentially help the query to run faster.
+** This mode is used for a DISTINCT query.
+** <li value="3"><p>
+** ^(If the sqlite3_vtab_distinct() interface returns 3, that means the
+** virtual table must return rows in the order defined by "aOrderBy" as
+** if the sqlite3_vtab_distinct() interface had returned 0.  However if
+** two or more rows in the result have the same values for all columns
+** identified by "colUsed", then all but one such row may optionally be
+** omitted.)^  Like when the return value is 2, the virtual table
+** is not required to omit rows that are duplicates over the "colUsed"
+** columns, but if the virtual table can do that without
+** too much extra effort, it could potentially help the query to run faster.
+** This mode is used for queries
+** that have both DISTINCT and ORDER BY clauses.
+** </ol>
+**
+** <p>The following table summarizes the conditions under which the
+** virtual table is allowed to set the "orderByConsumed" flag based on
+** the value returned by sqlite3_vtab_distinct().  This table is a
+** restatement of the previous four paragraphs:
+**
+** <table border=1 cellspacing=0 cellpadding=10 width="90%">
+** <tr>
+** <td valign="top">sqlite3_vtab_distinct() return value
+** <td valign="top">Rows are returned in aOrderBy order
+** <td valign="top">Rows with the same value in all aOrderBy columns are adjacent
+** <td valign="top">Duplicates over all colUsed columns may be omitted
+** <tr><td>0<td>yes<td>yes<td>no
+** <tr><td>1<td>no<td>yes<td>no
+** <tr><td>2<td>no<td>yes<td>yes
+** <tr><td>3<td>yes<td>yes<td>yes
+** </table>
+**
+** ^For the purposes of comparing virtual table output values to see if the
+** values are same value for sorting purposes, two NULL values are considered
+** to be the same.  In other words, the comparison operator is "IS"
+** (or "IS NOT DISTINCT FROM") and not "==".
+**
+** If a virtual table implementation is unable to meet the requirements
+** specified above, then it must not set the "orderByConsumed" flag in the
+** [sqlite3_index_info] object or an incorrect answer may result.
+**
+** ^A virtual table implementation is always free to return rows in any order
+** it wants, as long as the "orderByConsumed" flag is not set.  ^When the
+** the "orderByConsumed" flag is unset, the query planner will add extra
+** [bytecode] to ensure that the final results returned by the SQL query are
+** ordered correctly.  The use of the "orderByConsumed" flag and the
+** sqlite3_vtab_distinct() interface is merely an optimization.  ^Careful
+** use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
+** flag might help queries against a virtual table to run faster.  Being
+** overly aggressive and setting the "orderByConsumed" flag when it is not
+** valid to do so, on the other hand, might cause SQLite to return incorrect
+** results.
+*/
+SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info*);
+
+/*
+** CAPI3REF: Identify and handle IN constraints in xBestIndex
+**
+** This interface may only be used from within an
+** [xBestIndex|xBestIndex() method] of a [virtual table] implementation.
+** The result of invoking this interface from any other context is
+** undefined and probably harmful.
+**
+** ^(A constraint on a virtual table of the form
+** "[IN operator|column IN (...)]" is
+** communicated to the xBestIndex method as a
+** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^  If xBestIndex wants to use
+** this constraint, it must set the corresponding
+** aConstraintUsage[].argvIndex to a positive integer.  ^(Then, under
+** the usual mode of handling IN operators, SQLite generates [bytecode]
+** that invokes the [xFilter|xFilter() method] once for each value
+** on the right-hand side of the IN operator.)^  Thus the virtual table
+** only sees a single value from the right-hand side of the IN operator
+** at a time.
+**
+** In some cases, however, it would be advantageous for the virtual
+** table to see all values on the right-hand of the IN operator all at
+** once.  The sqlite3_vtab_in() interfaces facilitates this in two ways:
+**
+** <ol>
+** <li><p>
+**   ^A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
+**   if and only if the [sqlite3_index_info|P->aConstraint][N] constraint
+**   is an [IN operator] that can be processed all at once.  ^In other words,
+**   sqlite3_vtab_in() with -1 in the third argument is a mechanism
+**   by which the virtual table can ask SQLite if all-at-once processing
+**   of the IN operator is even possible.
+**
+** <li><p>
+**   ^A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
+**   to SQLite that the virtual table does or does not want to process
+**   the IN operator all-at-once, respectively.  ^Thus when the third
+**   parameter (F) is non-negative, this interface is the mechanism by
+**   which the virtual table tells SQLite how it wants to process the
+**   IN operator.
+** </ol>
+**
+** ^The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
+** within the same xBestIndex method call.  ^For any given P,N pair,
+** the return value from sqlite3_vtab_in(P,N,F) will always be the same
+** within the same xBestIndex call.  ^If the interface returns true
+** (non-zero), that means that the constraint is an IN operator
+** that can be processed all-at-once.  ^If the constraint is not an IN
+** operator or cannot be processed all-at-once, then the interface returns
+** false.
+**
+** ^(All-at-once processing of the IN operator is selected if both of the
+** following conditions are met:
+**
+** <ol>
+** <li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
+** integer.  This is how the virtual table tells SQLite that it wants to
+** use the N-th constraint.
+**
+** <li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
+** non-negative had F>=1.
+** </ol>)^
+**
+** ^If either or both of the conditions above are false, then SQLite uses
+** the traditional one-at-a-time processing strategy for the IN constraint.
+** ^If both conditions are true, then the argvIndex-th parameter to the
+** xFilter method will be an [sqlite3_value] that appears to be NULL,
+** but which can be passed to [sqlite3_vtab_in_first()] and
+** [sqlite3_vtab_in_next()] to find all values on the right-hand side
+** of the IN constraint.
+*/
+SQLITE_API int sqlite3_vtab_in(sqlite3_index_info*, int iCons, int bHandle);
+
+/*
+** CAPI3REF: Find all elements on the right-hand side of an IN constraint.
+**
+** These interfaces are only useful from within the
+** [xFilter|xFilter() method] of a [virtual table] implementation.
+** The result of invoking these interfaces from any other context
+** is undefined and probably harmful.
+**
+** The X parameter in a call to sqlite3_vtab_in_first(X,P) or
+** sqlite3_vtab_in_next(X,P) should be one of the parameters to the
+** xFilter method which invokes these routines, and specifically
+** a parameter that was previously selected for all-at-once IN constraint
+** processing use the [sqlite3_vtab_in()] interface in the
+** [xBestIndex|xBestIndex method].  ^(If the X parameter is not
+** an xFilter argument that was selected for all-at-once IN constraint
+** processing, then these routines return [SQLITE_ERROR].)^
+**
+** ^(Use these routines to access all values on the right-hand side
+** of the IN constraint using code like the following:
+**
+** <blockquote><pre>
+**    for(rc=sqlite3_vtab_in_first(pList, &pVal);
+**        rc==SQLITE_OK && pVal;
+**        rc=sqlite3_vtab_in_next(pList, &pVal)
+**    ){
+**      // do something with pVal
+**    }
+**    if( rc!=SQLITE_OK ){
+**      // an error has occurred
+**    }
+** </pre></blockquote>)^
+**
+** ^On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
+** routines return SQLITE_OK and set *P to point to the first or next value
+** on the RHS of the IN constraint.  ^If there are no more values on the
+** right hand side of the IN constraint, then *P is set to NULL and these
+** routines return [SQLITE_DONE].  ^The return value might be
+** some other value, such as SQLITE_NOMEM, in the event of a malfunction.
+**
+** The *ppOut values returned by these routines are only valid until the
+** next call to either of these routines or until the end of the xFilter
+** method from which these routines were called.  If the virtual table
+** implementation needs to retain the *ppOut values for longer, it must make
+** copies.  The *ppOut values are [protected sqlite3_value|protected].
+*/
+SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut);
+SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut);
+
+/*
+** CAPI3REF: Constraint values in xBestIndex()
+** METHOD: sqlite3_index_info
+**
+** This API may only be used from within the [xBestIndex|xBestIndex method]
+** of a [virtual table] implementation. The result of calling this interface
+** from outside of an xBestIndex method are undefined and probably harmful.
+**
+** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
+** the [xBestIndex] method of a [virtual table] implementation, with P being
+** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
+** J being a 0-based index into P->aConstraint[], then this routine
+** attempts to set *V to the value of the right-hand operand of
+** that constraint if the right-hand operand is known.  ^If the
+** right-hand operand is not known, then *V is set to a NULL pointer.
+** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
+** and only if *V is set to a value.  ^The sqlite3_vtab_rhs_value(P,J,V)
+** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
+** constraint is not available.  ^The sqlite3_vtab_rhs_value() interface
+** can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
+** something goes wrong.
+**
+** The sqlite3_vtab_rhs_value() interface is usually only successful if
+** the right-hand operand of a constraint is a literal value in the original
+** SQL statement.  If the right-hand operand is an expression or a reference
+** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
+** will probably return [SQLITE_NOTFOUND].
+**
+** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
+** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand.  For such
+** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
+**
+** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
+** and remains valid for the duration of the xBestIndex method call.
+** ^When xBestIndex returns, the sqlite3_value object returned by
+** sqlite3_vtab_rhs_value() is automatically deallocated.
+**
+** The "_rhs_" in the name of this routine is an abbreviation for
+** "Right-Hand Side".
+*/
+SQLITE_API int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);
+
+/*
+** CAPI3REF: Conflict resolution modes
+** KEYWORDS: {conflict resolution mode}
+**
+** These constants are returned by [sqlite3_vtab_on_conflict()] to
+** inform a [virtual table] implementation what the [ON CONFLICT] mode
+** is for the SQL statement being evaluated.
+**
+** Note that the [SQLITE_IGNORE] constant is also used as a potential
+** return value from the [sqlite3_set_authorizer()] callback and that
+** [SQLITE_ABORT] is also a [result code].
+*/
+#define SQLITE_ROLLBACK 1
+/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
+#define SQLITE_FAIL     3
+/* #define SQLITE_ABORT 4  // Also an error code */
+#define SQLITE_REPLACE  5
+
+/*
+** CAPI3REF: Prepared Statement Scan Status Opcodes
+** KEYWORDS: {scanstatus options}
+**
+** The following constants can be used for the T parameter to the
+** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
+** different metric for sqlite3_stmt_scanstatus() to return.
+**
+** When the value returned to V is a string, space to hold that string is
+** managed by the prepared statement S and will be automatically freed when
+** S is finalized.
+**
+** Not all values are available for all query elements. When a value is
+** not available, the output variable is set to -1 if the value is numeric,
+** or to NULL if it is a string (SQLITE_SCANSTAT_NAME).
+**
+** <dl>
+** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
+** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
+** set to the total number of times that the X-th loop has run.</dd>
+**
+** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
+** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
+** to the total number of rows examined by all iterations of the X-th loop.</dd>
+**
+** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
+** <dd>^The "double" variable pointed to by the V parameter will be set to the
+** query planner's estimate for the average number of rows output from each
+** iteration of the X-th loop.  If the query planner's estimates was accurate,
+** then this value will approximate the quotient NVISIT/NLOOP and the
+** product of this value for all prior loops with the same SELECTID will
+** be the NLOOP value for the current loop.
+**
+** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
+** <dd>^The "const char *" variable pointed to by the V parameter will be set
+** to a zero-terminated UTF-8 string containing the name of the index or table
+** used for the X-th loop.
+**
+** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
+** <dd>^The "const char *" variable pointed to by the V parameter will be set
+** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
+** description for the X-th loop.
+**
+** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECTID</dt>
+** <dd>^The "int" variable pointed to by the V parameter will be set to the
+** id for the X-th query plan element. The id value is unique within the
+** statement. The select-id is the same value as is output in the first
+** column of an [EXPLAIN QUERY PLAN] query.
+**
+** [[SQLITE_SCANSTAT_PARENTID]] <dt>SQLITE_SCANSTAT_PARENTID</dt>
+** <dd>The "int" variable pointed to by the V parameter will be set to the
+** the id of the parent of the current query element, if applicable, or
+** to zero if the query element has no parent. This is the same value as
+** returned in the second column of an [EXPLAIN QUERY PLAN] query.
+**
+** [[SQLITE_SCANSTAT_NCYCLE]] <dt>SQLITE_SCANSTAT_NCYCLE</dt>
+** <dd>The sqlite3_int64 output value is set to the number of cycles,
+** according to the processor time-stamp counter, that elapsed while the
+** query element was being processed. This value is not available for
+** all query elements - if it is unavailable the output variable is
+** set to -1.
+** </dl>
+*/
+#define SQLITE_SCANSTAT_NLOOP    0
+#define SQLITE_SCANSTAT_NVISIT   1
+#define SQLITE_SCANSTAT_EST      2
+#define SQLITE_SCANSTAT_NAME     3
+#define SQLITE_SCANSTAT_EXPLAIN  4
+#define SQLITE_SCANSTAT_SELECTID 5
+#define SQLITE_SCANSTAT_PARENTID 6
+#define SQLITE_SCANSTAT_NCYCLE   7
+
+/*
+** CAPI3REF: Prepared Statement Scan Status
+** METHOD: sqlite3_stmt
+**
+** These interfaces return information about the predicted and measured
+** performance for pStmt.  Advanced applications can use this
+** interface to compare the predicted and the measured performance and
+** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
+**
+** Since this interface is expected to be rarely used, it is only
+** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
+** compile-time option.
+**
+** The "iScanStatusOp" parameter determines which status information to return.
+** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
+** of this interface is undefined. ^The requested measurement is written into
+** a variable pointed to by the "pOut" parameter.
+**
+** The "flags" parameter must be passed a mask of flags. At present only
+** one flag is defined - SQLITE_SCANSTAT_COMPLEX. If SQLITE_SCANSTAT_COMPLEX
+** is specified, then status information is available for all elements
+** of a query plan that are reported by "EXPLAIN QUERY PLAN" output. If
+** SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
+** that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
+** the EXPLAIN QUERY PLAN output) are available. Invoking API
+** sqlite3_stmt_scanstatus() is equivalent to calling
+** sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.
+**
+** Parameter "idx" identifies the specific query element to retrieve statistics
+** for. Query elements are numbered starting from zero. A value of -1 may be
+** to query for statistics regarding the entire query. ^If idx is out of range
+** - less than -1 or greater than or equal to the total number of query
+** elements used to implement the statement - a non-zero value is returned and
+** the variable that pOut points to is unchanged.
+**
+** See also: [sqlite3_stmt_scanstatus_reset()]
+*/
+SQLITE_API int sqlite3_stmt_scanstatus(
+  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
+  int idx,                  /* Index of loop to report on */
+  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
+  void *pOut                /* Result written here */
+);
+SQLITE_API int sqlite3_stmt_scanstatus_v2(
+  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
+  int idx,                  /* Index of loop to report on */
+  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
+  int flags,                /* Mask of flags defined below */
+  void *pOut                /* Result written here */
+);
+
+/*
+** CAPI3REF: Prepared Statement Scan Status
+** KEYWORDS: {scan status flags}
+*/
+#define SQLITE_SCANSTAT_COMPLEX 0x0001
+
+/*
+** CAPI3REF: Zero Scan-Status Counters
+** METHOD: sqlite3_stmt
+**
+** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
+**
+** This API is only available if the library is built with pre-processor
+** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
+*/
+SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
+
+/*
+** CAPI3REF: Flush caches to disk mid-transaction
+** METHOD: sqlite3
+**
+** ^If a write-transaction is open on [database connection] D when the
+** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
+** pages in the pager-cache that are not currently in use are written out
+** to disk. A dirty page may be in use if a database cursor created by an
+** active SQL statement is reading from it, or if it is page 1 of a database
+** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
+** interface flushes caches for all schemas - "main", "temp", and
+** any [attached] databases.
+**
+** ^If this function needs to obtain extra database locks before dirty pages
+** can be flushed to disk, it does so. ^If those locks cannot be obtained
+** immediately and there is a busy-handler callback configured, it is invoked
+** in the usual manner. ^If the required lock still cannot be obtained, then
+** the database is skipped and an attempt made to flush any dirty pages
+** belonging to the next (if any) database. ^If any databases are skipped
+** because locks cannot be obtained, but no other error occurs, this
+** function returns SQLITE_BUSY.
+**
+** ^If any other error occurs while flushing dirty pages to disk (for
+** example an IO error or out-of-memory condition), then processing is
+** abandoned and an SQLite [error code] is returned to the caller immediately.
+**
+** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
+**
+** ^This function does not set the database handle error code or message
+** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
+*/
+SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
+
+/*
+** CAPI3REF: The pre-update hook.
+** METHOD: sqlite3
+**
+** ^These interfaces are only available if SQLite is compiled using the
+** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
+**
+** ^The [sqlite3_preupdate_hook()] interface registers a callback function
+** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
+** on a database table.
+** ^At most one preupdate hook may be registered at a time on a single
+** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
+** the previous setting.
+** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
+** with a NULL pointer as the second parameter.
+** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
+** the first parameter to callbacks.
+**
+** ^The preupdate hook only fires for changes to real database tables; the
+** preupdate hook is not invoked for changes to [virtual tables] or to
+** system tables like sqlite_sequence or sqlite_stat1.
+**
+** ^The second parameter to the preupdate callback is a pointer to
+** the [database connection] that registered the preupdate hook.
+** ^The third parameter to the preupdate callback is one of the constants
+** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
+** kind of update operation that is about to occur.
+** ^(The fourth parameter to the preupdate callback is the name of the
+** database within the database connection that is being modified.  This
+** will be "main" for the main database or "temp" for TEMP tables or
+** the name given after the AS keyword in the [ATTACH] statement for attached
+** databases.)^
+** ^The fifth parameter to the preupdate callback is the name of the
+** table that is being modified.
+**
+** For an UPDATE or DELETE operation on a [rowid table], the sixth
+** parameter passed to the preupdate callback is the initial [rowid] of the
+** row being modified or deleted. For an INSERT operation on a rowid table,
+** or any operation on a WITHOUT ROWID table, the value of the sixth
+** parameter is undefined. For an INSERT or UPDATE on a rowid table the
+** seventh parameter is the final rowid value of the row being inserted
+** or updated. The value of the seventh parameter passed to the callback
+** function is not defined for operations on WITHOUT ROWID tables, or for
+** DELETE operations on rowid tables.
+**
+** ^The sqlite3_preupdate_hook(D,C,P) function returns the P argument from
+** the previous call on the same [database connection] D, or NULL for
+** the first call on D.
+**
+** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
+** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
+** provide additional information about a preupdate event. These routines
+** may only be called from within a preupdate callback.  Invoking any of
+** these routines from outside of a preupdate callback or with a
+** [database connection] pointer that is different from the one supplied
+** to the preupdate callback results in undefined and probably undesirable
+** behavior.
+**
+** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
+** in the row that is being inserted, updated, or deleted.
+**
+** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
+** a [protected sqlite3_value] that contains the value of the Nth column of
+** the table row before it is updated.  The N parameter must be between 0
+** and one less than the number of columns or the behavior will be
+** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
+** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
+** behavior is undefined.  The [sqlite3_value] that P points to
+** will be destroyed when the preupdate callback returns.
+**
+** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
+** a [protected sqlite3_value] that contains the value of the Nth column of
+** the table row after it is updated.  The N parameter must be between 0
+** and one less than the number of columns or the behavior will be
+** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
+** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
+** behavior is undefined.  The [sqlite3_value] that P points to
+** will be destroyed when the preupdate callback returns.
+**
+** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
+** callback was invoked as a result of a direct insert, update, or delete
+** operation; or 1 for inserts, updates, or deletes invoked by top-level
+** triggers; or 2 for changes resulting from triggers called by top-level
+** triggers; and so forth.
+**
+** When the [sqlite3_blob_write()] API is used to update a blob column,
+** the pre-update hook is invoked with SQLITE_DELETE. This is because the
+** in this case the new values are not available. In this case, when a
+** callback made with op==SQLITE_DELETE is actually a write using the
+** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
+** the index of the column being written. In other cases, where the
+** pre-update hook is being invoked for some other reason, including a
+** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
+**
+** See also:  [sqlite3_update_hook()]
+*/
+#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
+SQLITE_API void *sqlite3_preupdate_hook(
+  sqlite3 *db,
+  void(*xPreUpdate)(
+    void *pCtx,                   /* Copy of third arg to preupdate_hook() */
+    sqlite3 *db,                  /* Database handle */
+    int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
+    char const *zDb,              /* Database name */
+    char const *zName,            /* Table name */
+    sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
+    sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
+  ),
+  void*
+);
+SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
+SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
+SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
+SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
+SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *);
+#endif
+
+/*
+** CAPI3REF: Low-level system error code
+** METHOD: sqlite3
+**
+** ^Attempt to return the underlying operating system error code or error
+** number that caused the most recent I/O error or failure to open a file.
+** The return value is OS-dependent.  For example, on unix systems, after
+** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
+** called to get back the underlying "errno" that caused the problem, such
+** as ENOSPC, EAUTH, EISDIR, and so forth.
+*/
+SQLITE_API int sqlite3_system_errno(sqlite3*);
+
+/*
+** CAPI3REF: Database Snapshot
+** KEYWORDS: {snapshot} {sqlite3_snapshot}
+**
+** An instance of the snapshot object records the state of a [WAL mode]
+** database for some specific point in history.
+**
+** In [WAL mode], multiple [database connections] that are open on the
+** same database file can each be reading a different historical version
+** of the database file.  When a [database connection] begins a read
+** transaction, that connection sees an unchanging copy of the database
+** as it existed for the point in time when the transaction first started.
+** Subsequent changes to the database from other connections are not seen
+** by the reader until a new read transaction is started.
+**
+** The sqlite3_snapshot object records state information about an historical
+** version of the database file so that it is possible to later open a new read
+** transaction that sees that historical version of the database rather than
+** the most recent version.
+*/
+typedef struct sqlite3_snapshot {
+  unsigned char hidden[48];
+} sqlite3_snapshot;
+
+/*
+** CAPI3REF: Record A Database Snapshot
+** CONSTRUCTOR: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
+** new [sqlite3_snapshot] object that records the current state of
+** schema S in database connection D.  ^On success, the
+** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
+** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
+** If there is not already a read-transaction open on schema S when
+** this function is called, one is opened automatically.
+**
+** If a read-transaction is opened by this function, then it is guaranteed
+** that the returned snapshot object may not be invalidated by a database
+** writer or checkpointer until after the read-transaction is closed. This
+** is not guaranteed if a read-transaction is already open when this
+** function is called. In that case, any subsequent write or checkpoint
+** operation on the database may invalidate the returned snapshot handle,
+** even while the read-transaction remains open.
+**
+** The following must be true for this function to succeed. If any of
+** the following statements are false when sqlite3_snapshot_get() is
+** called, SQLITE_ERROR is returned. The final value of *P is undefined
+** in this case.
+**
+** <ul>
+**   <li> The database handle must not be in [autocommit mode].
+**
+**   <li> Schema S of [database connection] D must be a [WAL mode] database.
+**
+**   <li> There must not be a write transaction open on schema S of database
+**        connection D.
+**
+**   <li> One or more transactions must have been written to the current wal
+**        file since it was created on disk (by any connection). This means
+**        that a snapshot cannot be taken on a wal mode database with no wal
+**        file immediately after it is first opened. At least one transaction
+**        must be written to it first.
+** </ul>
+**
+** This function may also return SQLITE_NOMEM.  If it is called with the
+** database handle in autocommit mode but fails for some other reason,
+** whether or not a read transaction is opened on schema S is undefined.
+**
+** The [sqlite3_snapshot] object returned from a successful call to
+** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
+** to avoid a memory leak.
+**
+** The [sqlite3_snapshot_get()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
+  sqlite3 *db,
+  const char *zSchema,
+  sqlite3_snapshot **ppSnapshot
+);
+
+/*
+** CAPI3REF: Start a read transaction on an historical snapshot
+** METHOD: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
+** transaction or upgrades an existing one for schema S of
+** [database connection] D such that the read transaction refers to
+** historical [snapshot] P, rather than the most recent change to the
+** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
+** on success or an appropriate [error code] if it fails.
+**
+** ^In order to succeed, the database connection must not be in
+** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
+** is already a read transaction open on schema S, then the database handle
+** must have no active statements (SELECT statements that have been passed
+** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
+** SQLITE_ERROR is returned if either of these conditions is violated, or
+** if schema S does not exist, or if the snapshot object is invalid.
+**
+** ^A call to sqlite3_snapshot_open() will fail to open if the specified
+** snapshot has been overwritten by a [checkpoint]. In this case
+** SQLITE_ERROR_SNAPSHOT is returned.
+**
+** If there is already a read transaction open when this function is
+** invoked, then the same read transaction remains open (on the same
+** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
+** is returned. If another error code - for example SQLITE_PROTOCOL or an
+** SQLITE_IOERR error code - is returned, then the final state of the
+** read transaction is undefined. If SQLITE_OK is returned, then the
+** read transaction is now open on database snapshot P.
+**
+** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
+** database connection D does not know that the database file for
+** schema S is in [WAL mode].  A database connection might not know
+** that the database file is in [WAL mode] if there has been no prior
+** I/O on that database connection, or if the database entered [WAL mode]
+** after the most recent I/O on the database connection.)^
+** (Hint: Run "[PRAGMA application_id]" against a newly opened
+** database connection in order to make it ready to use snapshots.)
+**
+** The [sqlite3_snapshot_open()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
+  sqlite3 *db,
+  const char *zSchema,
+  sqlite3_snapshot *pSnapshot
+);
+
+/*
+** CAPI3REF: Destroy a snapshot
+** DESTRUCTOR: sqlite3_snapshot
+**
+** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
+** The application must eventually free every [sqlite3_snapshot] object
+** using this routine to avoid a memory leak.
+**
+** The [sqlite3_snapshot_free()] interface is only available when the
+** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
+
+/*
+** CAPI3REF: Compare the ages of two snapshot handles.
+** METHOD: sqlite3_snapshot
+**
+** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
+** of two valid snapshot handles.
+**
+** If the two snapshot handles are not associated with the same database
+** file, the result of the comparison is undefined.
+**
+** Additionally, the result of the comparison is only valid if both of the
+** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
+** last time the wal file was deleted. The wal file is deleted when the
+** database is changed back to rollback mode or when the number of database
+** clients drops to zero. If either snapshot handle was obtained before the
+** wal file was last deleted, the value returned by this function
+** is undefined.
+**
+** Otherwise, this API returns a negative value if P1 refers to an older
+** snapshot than P2, zero if the two handles refer to the same database
+** snapshot, and a positive value if P1 is a newer snapshot than P2.
+**
+** This interface is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SNAPSHOT] option.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
+  sqlite3_snapshot *p1,
+  sqlite3_snapshot *p2
+);
+
+/*
+** CAPI3REF: Recover snapshots from a wal file
+** METHOD: sqlite3_snapshot
+**
+** If a [WAL file] remains on disk after all database connections close
+** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
+** or because the last process to have the database opened exited without
+** calling [sqlite3_close()]) and a new connection is subsequently opened
+** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
+** will only be able to open the last transaction added to the WAL file
+** even though the WAL file contains other valid transactions.
+**
+** This function attempts to scan the WAL file associated with database zDb
+** of database handle db and make all valid snapshots available to
+** sqlite3_snapshot_open(). It is an error if there is already a read
+** transaction open on the database, or if the database is not a WAL mode
+** database.
+**
+** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
+**
+** This interface is only available if SQLite is compiled with the
+** [SQLITE_ENABLE_SNAPSHOT] option.
+*/
+SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
+
+/*
+** CAPI3REF: Serialize a database
+**
+** The sqlite3_serialize(D,S,P,F) interface returns a pointer to
+** memory that is a serialization of the S database on
+** [database connection] D.  If S is a NULL pointer, the main database is used.
+** If P is not a NULL pointer, then the size of the database in bytes
+** is written into *P.
+**
+** For an ordinary on-disk database file, the serialization is just a
+** copy of the disk file.  For an in-memory database or a "TEMP" database,
+** the serialization is the same sequence of bytes which would be written
+** to disk if that database where backed up to disk.
+**
+** The usual case is that sqlite3_serialize() copies the serialization of
+** the database into memory obtained from [sqlite3_malloc64()] and returns
+** a pointer to that memory.  The caller is responsible for freeing the
+** returned value to avoid a memory leak.  However, if the F argument
+** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
+** are made, and the sqlite3_serialize() function will return a pointer
+** to the contiguous memory representation of the database that SQLite
+** is currently using for that database, or NULL if the no such contiguous
+** memory representation of the database exists.  A contiguous memory
+** representation of the database will usually only exist if there has
+** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
+** values of D and S.
+** The size of the database is written into *P even if the
+** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
+** of the database exists.
+**
+** After the call, if the SQLITE_SERIALIZE_NOCOPY bit had been set,
+** the returned buffer content will remain accessible and unchanged
+** until either the next write operation on the connection or when
+** the connection is closed, and applications must not modify the
+** buffer. If the bit had been clear, the returned buffer will not
+** be accessed by SQLite after the call.
+**
+** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
+** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
+** allocation error occurs.
+**
+** This interface is omitted if SQLite is compiled with the
+** [SQLITE_OMIT_DESERIALIZE] option.
+*/
+SQLITE_API unsigned char *sqlite3_serialize(
+  sqlite3 *db,           /* The database connection */
+  const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
+  sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
+  unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3_serialize
+**
+** Zero or more of the following constants can be OR-ed together for
+** the F argument to [sqlite3_serialize(D,S,P,F)].
+**
+** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
+** a pointer to contiguous in-memory database that it is currently using,
+** without making a copy of the database.  If SQLite is not currently using
+** a contiguous in-memory database, then this option causes
+** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
+** using a contiguous in-memory database if it has been initialized by a
+** prior call to [sqlite3_deserialize()].
+*/
+#define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
+
+/*
+** CAPI3REF: Deserialize a database
+**
+** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
+** [database connection] D to disconnect from database S and then
+** reopen S as an in-memory database based on the serialization contained
+** in P.  The serialized database P is N bytes in size.  M is the size of
+** the buffer P, which might be larger than N.  If M is larger than N, and
+** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
+** permitted to add content to the in-memory database as long as the total
+** size does not exceed M bytes.
+**
+** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
+** invoke sqlite3_free() on the serialization buffer when the database
+** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
+** SQLite will try to increase the buffer size using sqlite3_realloc64()
+** if writes on the database cause it to grow larger than M bytes.
+**
+** Applications must not modify the buffer P or invalidate it before
+** the database connection D is closed.
+**
+** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
+** database is currently in a read transaction or is involved in a backup
+** operation.
+**
+** It is not possible to deserialized into the TEMP database.  If the
+** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
+** function returns SQLITE_ERROR.
+**
+** The deserialized database should not be in [WAL mode].  If the database
+** is in WAL mode, then any attempt to use the database file will result
+** in an [SQLITE_CANTOPEN] error.  The application can set the
+** [file format version numbers] (bytes 18 and 19) of the input database P
+** to 0x01 prior to invoking sqlite3_deserialize(D,S,P,N,M,F) to force the
+** database file into rollback mode and work around this limitation.
+**
+** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
+** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
+** [sqlite3_free()] is invoked on argument P prior to returning.
+**
+** This interface is omitted if SQLite is compiled with the
+** [SQLITE_OMIT_DESERIALIZE] option.
+*/
+SQLITE_API int sqlite3_deserialize(
+  sqlite3 *db,            /* The database connection */
+  const char *zSchema,    /* Which DB to reopen with the deserialization */
+  unsigned char *pData,   /* The serialized database content */
+  sqlite3_int64 szDb,     /* Number bytes in the deserialization */
+  sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
+  unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3_deserialize()
+**
+** The following are allowed values for 6th argument (the F argument) to
+** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
+**
+** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
+** in the P argument is held in memory obtained from [sqlite3_malloc64()]
+** and that SQLite should take ownership of this memory and automatically
+** free it when it has finished using it.  Without this flag, the caller
+** is responsible for freeing any dynamically allocated memory.
+**
+** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
+** grow the size of the database using calls to [sqlite3_realloc64()].  This
+** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
+** Without this flag, the deserialized database cannot increase in size beyond
+** the number of bytes specified by the M parameter.
+**
+** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
+** should be treated as read-only.
+*/
+#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
+#define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
+#define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
+
+/*
+** Undo the hack that converts floating point types to integer for
+** builds on processors without floating point support.
+*/
+#ifdef SQLITE_OMIT_FLOATING_POINT
+# undef double
+#endif
+
+#if defined(__wasi__)
+# undef SQLITE_WASI
+# define SQLITE_WASI 1
+# ifndef SQLITE_OMIT_LOAD_EXTENSION
+#  define SQLITE_OMIT_LOAD_EXTENSION
+# endif
+# ifndef SQLITE_THREADSAFE
+#  define SQLITE_THREADSAFE 0
+# endif
+#endif
+
+#ifdef __cplusplus
+}  /* End of the 'extern "C"' block */
+#endif
+/* #endif for SQLITE3_H will be added by mksqlite3.tcl */
+
+/******** Begin file sqlite3rtree.h *********/
+/*
+** 2010 August 30
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+*/
+
+#ifndef _SQLITE3RTREE_H_
+#define _SQLITE3RTREE_H_
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
+typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
+
+/* The double-precision datatype used by RTree depends on the
+** SQLITE_RTREE_INT_ONLY compile-time option.
+*/
+#ifdef SQLITE_RTREE_INT_ONLY
+  typedef sqlite3_int64 sqlite3_rtree_dbl;
+#else
+  typedef double sqlite3_rtree_dbl;
+#endif
+
+/*
+** Register a geometry callback named zGeom that can be used as part of an
+** R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_geometry_callback(
+  sqlite3 *db,
+  const char *zGeom,
+  int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
+  void *pContext
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the first
+** argument to callbacks registered using rtree_geometry_callback().
+*/
+struct sqlite3_rtree_geometry {
+  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
+  int nParam;                     /* Size of array aParam[] */
+  sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
+  void *pUser;                    /* Callback implementation user data */
+  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
+};
+
+/*
+** Register a 2nd-generation geometry callback named zScore that can be
+** used as part of an R-Tree geometry query as follows:
+**
+**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
+*/
+SQLITE_API int sqlite3_rtree_query_callback(
+  sqlite3 *db,
+  const char *zQueryFunc,
+  int (*xQueryFunc)(sqlite3_rtree_query_info*),
+  void *pContext,
+  void (*xDestructor)(void*)
+);
+
+
+/*
+** A pointer to a structure of the following type is passed as the
+** argument to scored geometry callback registered using
+** sqlite3_rtree_query_callback().
+**
+** Note that the first 5 fields of this structure are identical to
+** sqlite3_rtree_geometry.  This structure is a subclass of
+** sqlite3_rtree_geometry.
+*/
+struct sqlite3_rtree_query_info {
+  void *pContext;                   /* pContext from when function registered */
+  int nParam;                       /* Number of function parameters */
+  sqlite3_rtree_dbl *aParam;        /* value of function parameters */
+  void *pUser;                      /* callback can use this, if desired */
+  void (*xDelUser)(void*);          /* function to free pUser */
+  sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
+  unsigned int *anQueue;            /* Number of pending entries in the queue */
+  int nCoord;                       /* Number of coordinates */
+  int iLevel;                       /* Level of current node or entry */
+  int mxLevel;                      /* The largest iLevel value in the tree */
+  sqlite3_int64 iRowid;             /* Rowid for current entry */
+  sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
+  int eParentWithin;                /* Visibility of parent node */
+  int eWithin;                      /* OUT: Visibility */
+  sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
+  /* The following fields are only available in 3.8.11 and later */
+  sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
+};
+
+/*
+** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
+*/
+#define NOT_WITHIN       0   /* Object completely outside of query region */
+#define PARTLY_WITHIN    1   /* Object partially overlaps query region */
+#define FULLY_WITHIN     2   /* Object fully contained within query region */
+
+
+#ifdef __cplusplus
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif  /* ifndef _SQLITE3RTREE_H_ */
+
+/******** End of sqlite3rtree.h *********/
+/******** Begin file sqlite3session.h *********/
+
+#if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
+#define __SQLITESESSION_H_ 1
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/*
+** CAPI3REF: Session Object Handle
+**
+** An instance of this object is a [session] that can be used to
+** record changes to a database.
+*/
+typedef struct sqlite3_session sqlite3_session;
+
+/*
+** CAPI3REF: Changeset Iterator Handle
+**
+** An instance of this object acts as a cursor for iterating
+** over the elements of a [changeset] or [patchset].
+*/
+typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
+
+/*
+** CAPI3REF: Create A New Session Object
+** CONSTRUCTOR: sqlite3_session
+**
+** Create a new session object attached to database handle db. If successful,
+** a pointer to the new object is written to *ppSession and SQLITE_OK is
+** returned. If an error occurs, *ppSession is set to NULL and an SQLite
+** error code (e.g. SQLITE_NOMEM) is returned.
+**
+** It is possible to create multiple session objects attached to a single
+** database handle.
+**
+** Session objects created using this function should be deleted using the
+** [sqlite3session_delete()] function before the database handle that they
+** are attached to is itself closed. If the database handle is closed before
+** the session object is deleted, then the results of calling any session
+** module function, including [sqlite3session_delete()] on the session object
+** are undefined.
+**
+** Because the session module uses the [sqlite3_preupdate_hook()] API, it
+** is not possible for an application to register a pre-update hook on a
+** database handle that has one or more session objects attached. Nor is
+** it possible to create a session object attached to a database handle for
+** which a pre-update hook is already defined. The results of attempting
+** either of these things are undefined.
+**
+** The session object will be used to create changesets for tables in
+** database zDb, where zDb is either "main", or "temp", or the name of an
+** attached database. It is not an error if database zDb is not attached
+** to the database when the session object is created.
+*/
+SQLITE_API int sqlite3session_create(
+  sqlite3 *db,                    /* Database handle */
+  const char *zDb,                /* Name of db (e.g. "main") */
+  sqlite3_session **ppSession     /* OUT: New session object */
+);
+
+/*
+** CAPI3REF: Delete A Session Object
+** DESTRUCTOR: sqlite3_session
+**
+** Delete a session object previously allocated using
+** [sqlite3session_create()]. Once a session object has been deleted, the
+** results of attempting to use pSession with any other session module
+** function are undefined.
+**
+** Session objects must be deleted before the database handle to which they
+** are attached is closed. Refer to the documentation for
+** [sqlite3session_create()] for details.
+*/
+SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Configure a Session Object
+** METHOD: sqlite3_session
+**
+** This method is used to configure a session object after it has been
+** created. At present the only valid values for the second parameter are
+** [SQLITE_SESSION_OBJCONFIG_SIZE] and [SQLITE_SESSION_OBJCONFIG_ROWID].
+**
+*/
+SQLITE_API int sqlite3session_object_config(sqlite3_session*, int op, void *pArg);
+
+/*
+** CAPI3REF: Options for sqlite3session_object_config
+**
+** The following values may passed as the the 2nd parameter to
+** sqlite3session_object_config().
+**
+** <dt>SQLITE_SESSION_OBJCONFIG_SIZE <dd>
+**   This option is used to set, clear or query the flag that enables
+**   the [sqlite3session_changeset_size()] API. Because it imposes some
+**   computational overhead, this API is disabled by default. Argument
+**   pArg must point to a value of type (int). If the value is initially
+**   0, then the sqlite3session_changeset_size() API is disabled. If it
+**   is greater than 0, then the same API is enabled. Or, if the initial
+**   value is less than zero, no change is made. In all cases the (int)
+**   variable is set to 1 if the sqlite3session_changeset_size() API is
+**   enabled following the current call, or 0 otherwise.
+**
+**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
+**   the first table has been attached to the session object.
+**
+** <dt>SQLITE_SESSION_OBJCONFIG_ROWID <dd>
+**   This option is used to set, clear or query the flag that enables
+**   collection of data for tables with no explicit PRIMARY KEY.
+**
+**   Normally, tables with no explicit PRIMARY KEY are simply ignored
+**   by the sessions module. However, if this flag is set, it behaves
+**   as if such tables have a column "_rowid_ INTEGER PRIMARY KEY" inserted
+**   as their leftmost columns.
+**
+**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
+**   the first table has been attached to the session object.
+*/
+#define SQLITE_SESSION_OBJCONFIG_SIZE  1
+#define SQLITE_SESSION_OBJCONFIG_ROWID 2
+
+/*
+** CAPI3REF: Enable Or Disable A Session Object
+** METHOD: sqlite3_session
+**
+** Enable or disable the recording of changes by a session object. When
+** enabled, a session object records changes made to the database. When
+** disabled - it does not. A newly created session object is enabled.
+** Refer to the documentation for [sqlite3session_changeset()] for further
+** details regarding how enabling and disabling a session object affects
+** the eventual changesets.
+**
+** Passing zero to this function disables the session. Passing a value
+** greater than zero enables it. Passing a value less than zero is a
+** no-op, and may be used to query the current state of the session.
+**
+** The return value indicates the final state of the session object: 0 if
+** the session is disabled, or 1 if it is enabled.
+*/
+SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
+
+/*
+** CAPI3REF: Set Or Clear the Indirect Change Flag
+** METHOD: sqlite3_session
+**
+** Each change recorded by a session object is marked as either direct or
+** indirect. A change is marked as indirect if either:
+**
+** <ul>
+**   <li> The session object "indirect" flag is set when the change is
+**        made, or
+**   <li> The change is made by an SQL trigger or foreign key action
+**        instead of directly as a result of a users SQL statement.
+** </ul>
+**
+** If a single row is affected by more than one operation within a session,
+** then the change is considered indirect if all operations meet the criteria
+** for an indirect change above, or direct otherwise.
+**
+** This function is used to set, clear or query the session object indirect
+** flag.  If the second argument passed to this function is zero, then the
+** indirect flag is cleared. If it is greater than zero, the indirect flag
+** is set. Passing a value less than zero does not modify the current value
+** of the indirect flag, and may be used to query the current state of the
+** indirect flag for the specified session object.
+**
+** The return value indicates the final state of the indirect flag: 0 if
+** it is clear, or 1 if it is set.
+*/
+SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
+
+/*
+** CAPI3REF: Attach A Table To A Session Object
+** METHOD: sqlite3_session
+**
+** If argument zTab is not NULL, then it is the name of a table to attach
+** to the session object passed as the first argument. All subsequent changes
+** made to the table while the session object is enabled will be recorded. See
+** documentation for [sqlite3session_changeset()] for further details.
+**
+** Or, if argument zTab is NULL, then changes are recorded for all tables
+** in the database. If additional tables are added to the database (by
+** executing "CREATE TABLE" statements) after this call is made, changes for
+** the new tables are also recorded.
+**
+** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
+** defined as part of their CREATE TABLE statement. It does not matter if the
+** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
+** KEY may consist of a single column, or may be a composite key.
+**
+** It is not an error if the named table does not exist in the database. Nor
+** is it an error if the named table does not have a PRIMARY KEY. However,
+** no changes will be recorded in either of these scenarios.
+**
+** Changes are not recorded for individual rows that have NULL values stored
+** in one or more of their PRIMARY KEY columns.
+**
+** SQLITE_OK is returned if the call completes without error. Or, if an error
+** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
+**
+** <h3>Special sqlite_stat1 Handling</h3>
+**
+** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
+** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
+**  <pre>
+**        CREATE TABLE sqlite_stat1(tbl,idx,stat)
+**  </pre>
+**
+** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
+** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
+** are recorded for rows for which (idx IS NULL) is true. However, for such
+** rows a zero-length blob (SQL value X'') is stored in the changeset or
+** patchset instead of a NULL value. This allows such changesets to be
+** manipulated by legacy implementations of sqlite3changeset_invert(),
+** concat() and similar.
+**
+** The sqlite3changeset_apply() function automatically converts the
+** zero-length blob back to a NULL value when updating the sqlite_stat1
+** table. However, if the application calls sqlite3changeset_new(),
+** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
+** iterator directly (including on a changeset iterator passed to a
+** conflict-handler callback) then the X'' value is returned. The application
+** must translate X'' to NULL itself if required.
+**
+** Legacy (older than 3.22.0) versions of the sessions module cannot capture
+** changes made to the sqlite_stat1 table. Legacy versions of the
+** sqlite3changeset_apply() function silently ignore any modifications to the
+** sqlite_stat1 table that are part of a changeset or patchset.
+*/
+SQLITE_API int sqlite3session_attach(
+  sqlite3_session *pSession,      /* Session object */
+  const char *zTab                /* Table name */
+);
+
+/*
+** CAPI3REF: Set a table filter on a Session Object.
+** METHOD: sqlite3_session
+**
+** The second argument (xFilter) is the "filter callback". For changes to rows
+** in tables that are not attached to the Session object, the filter is called
+** to determine whether changes to the table's rows should be tracked or not.
+** If xFilter returns 0, changes are not tracked. Note that once a table is
+** attached, xFilter will not be called again.
+*/
+SQLITE_API void sqlite3session_table_filter(
+  sqlite3_session *pSession,      /* Session object */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of third arg to _filter_table() */
+    const char *zTab              /* Table name */
+  ),
+  void *pCtx                      /* First argument passed to xFilter */
+);
+
+/*
+** CAPI3REF: Generate A Changeset From A Session Object
+** METHOD: sqlite3_session
+**
+** Obtain a changeset containing changes to the tables attached to the
+** session object passed as the first argument. If successful,
+** set *ppChangeset to point to a buffer containing the changeset
+** and *pnChangeset to the size of the changeset in bytes before returning
+** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
+** zero and return an SQLite error code.
+**
+** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
+** each representing a change to a single row of an attached table. An INSERT
+** change contains the values of each field of a new database row. A DELETE
+** contains the original values of each field of a deleted database row. An
+** UPDATE change contains the original values of each field of an updated
+** database row along with the updated values for each updated non-primary-key
+** column. It is not possible for an UPDATE change to represent a change that
+** modifies the values of primary key columns. If such a change is made, it
+** is represented in a changeset as a DELETE followed by an INSERT.
+**
+** Changes are not recorded for rows that have NULL values stored in one or
+** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
+** no corresponding change is present in the changesets returned by this
+** function. If an existing row with one or more NULL values stored in
+** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
+** only an INSERT is appears in the changeset. Similarly, if an existing row
+** with non-NULL PRIMARY KEY values is updated so that one or more of its
+** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
+** DELETE change only.
+**
+** The contents of a changeset may be traversed using an iterator created
+** using the [sqlite3changeset_start()] API. A changeset may be applied to
+** a database with a compatible schema using the [sqlite3changeset_apply()]
+** API.
+**
+** Within a changeset generated by this function, all changes related to a
+** single table are grouped together. In other words, when iterating through
+** a changeset or when applying a changeset to a database, all changes related
+** to a single table are processed before moving on to the next table. Tables
+** are sorted in the same order in which they were attached (or auto-attached)
+** to the sqlite3_session object. The order in which the changes related to
+** a single table are stored is undefined.
+**
+** Following a successful call to this function, it is the responsibility of
+** the caller to eventually free the buffer that *ppChangeset points to using
+** [sqlite3_free()].
+**
+** <h3>Changeset Generation</h3>
+**
+** Once a table has been attached to a session object, the session object
+** records the primary key values of all new rows inserted into the table.
+** It also records the original primary key and other column values of any
+** deleted or updated rows. For each unique primary key value, data is only
+** recorded once - the first time a row with said primary key is inserted,
+** updated or deleted in the lifetime of the session.
+**
+** There is one exception to the previous paragraph: when a row is inserted,
+** updated or deleted, if one or more of its primary key columns contain a
+** NULL value, no record of the change is made.
+**
+** The session object therefore accumulates two types of records - those
+** that consist of primary key values only (created when the user inserts
+** a new record) and those that consist of the primary key values and the
+** original values of other table columns (created when the users deletes
+** or updates a record).
+**
+** When this function is called, the requested changeset is created using
+** both the accumulated records and the current contents of the database
+** file. Specifically:
+**
+** <ul>
+**   <li> For each record generated by an insert, the database is queried
+**        for a row with a matching primary key. If one is found, an INSERT
+**        change is added to the changeset. If no such row is found, no change
+**        is added to the changeset.
+**
+**   <li> For each record generated by an update or delete, the database is
+**        queried for a row with a matching primary key. If such a row is
+**        found and one or more of the non-primary key fields have been
+**        modified from their original values, an UPDATE change is added to
+**        the changeset. Or, if no such row is found in the table, a DELETE
+**        change is added to the changeset. If there is a row with a matching
+**        primary key in the database, but all fields contain their original
+**        values, no change is added to the changeset.
+** </ul>
+**
+** This means, amongst other things, that if a row is inserted and then later
+** deleted while a session object is active, neither the insert nor the delete
+** will be present in the changeset. Or if a row is deleted and then later a
+** row with the same primary key values inserted while a session object is
+** active, the resulting changeset will contain an UPDATE change instead of
+** a DELETE and an INSERT.
+**
+** When a session object is disabled (see the [sqlite3session_enable()] API),
+** it does not accumulate records when rows are inserted, updated or deleted.
+** This may appear to have some counter-intuitive effects if a single row
+** is written to more than once during a session. For example, if a row
+** is inserted while a session object is enabled, then later deleted while
+** the same session object is disabled, no INSERT record will appear in the
+** changeset, even though the delete took place while the session was disabled.
+** Or, if one field of a row is updated while a session is disabled, and
+** another field of the same row is updated while the session is enabled, the
+** resulting changeset will contain an UPDATE change that updates both fields.
+*/
+SQLITE_API int sqlite3session_changeset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
+  void **ppChangeset              /* OUT: Buffer containing changeset */
+);
+
+/*
+** CAPI3REF: Return An Upper-limit For The Size Of The Changeset
+** METHOD: sqlite3_session
+**
+** By default, this function always returns 0. For it to return
+** a useful result, the sqlite3_session object must have been configured
+** to enable this API using sqlite3session_object_config() with the
+** SQLITE_SESSION_OBJCONFIG_SIZE verb.
+**
+** When enabled, this function returns an upper limit, in bytes, for the size
+** of the changeset that might be produced if sqlite3session_changeset() were
+** called. The final changeset size might be equal to or smaller than the
+** size in bytes returned by this function.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Load The Difference Between Tables Into A Session
+** METHOD: sqlite3_session
+**
+** If it is not already attached to the session object passed as the first
+** argument, this function attaches table zTbl in the same manner as the
+** [sqlite3session_attach()] function. If zTbl does not exist, or if it
+** does not have a primary key, this function is a no-op (but does not return
+** an error).
+**
+** Argument zFromDb must be the name of a database ("main", "temp" etc.)
+** attached to the same database handle as the session object that contains
+** a table compatible with the table attached to the session by this function.
+** A table is considered compatible if it:
+**
+** <ul>
+**   <li> Has the same name,
+**   <li> Has the same set of columns declared in the same order, and
+**   <li> Has the same PRIMARY KEY definition.
+** </ul>
+**
+** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
+** are compatible but do not have any PRIMARY KEY columns, it is not an error
+** but no changes are added to the session object. As with other session
+** APIs, tables without PRIMARY KEYs are simply ignored.
+**
+** This function adds a set of changes to the session object that could be
+** used to update the table in database zFrom (call this the "from-table")
+** so that its content is the same as the table attached to the session
+** object (call this the "to-table"). Specifically:
+**
+** <ul>
+**   <li> For each row (primary key) that exists in the to-table but not in
+**     the from-table, an INSERT record is added to the session object.
+**
+**   <li> For each row (primary key) that exists in the to-table but not in
+**     the from-table, a DELETE record is added to the session object.
+**
+**   <li> For each row (primary key) that exists in both tables, but features
+**     different non-PK values in each, an UPDATE record is added to the
+**     session.
+** </ul>
+**
+** To clarify, if this function is called and then a changeset constructed
+** using [sqlite3session_changeset()], then after applying that changeset to
+** database zFrom the contents of the two compatible tables would be
+** identical.
+**
+** It an error if database zFrom does not exist or does not contain the
+** required compatible table.
+**
+** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
+** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
+** may be set to point to a buffer containing an English language error
+** message. It is the responsibility of the caller to free this buffer using
+** sqlite3_free().
+*/
+SQLITE_API int sqlite3session_diff(
+  sqlite3_session *pSession,
+  const char *zFromDb,
+  const char *zTbl,
+  char **pzErrMsg
+);
+
+
+/*
+** CAPI3REF: Generate A Patchset From A Session Object
+** METHOD: sqlite3_session
+**
+** The differences between a patchset and a changeset are that:
+**
+** <ul>
+**   <li> DELETE records consist of the primary key fields only. The
+**        original values of other fields are omitted.
+**   <li> The original values of any modified fields are omitted from
+**        UPDATE records.
+** </ul>
+**
+** A patchset blob may be used with up to date versions of all
+** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
+** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
+** attempting to use a patchset blob with old versions of the
+** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
+**
+** Because the non-primary key "old.*" fields are omitted, no
+** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
+** is passed to the sqlite3changeset_apply() API. Other conflict types work
+** in the same way as for changesets.
+**
+** Changes within a patchset are ordered in the same way as for changesets
+** generated by the sqlite3session_changeset() function (i.e. all changes for
+** a single table are grouped together, tables appear in the order in which
+** they were attached to the session object).
+*/
+SQLITE_API int sqlite3session_patchset(
+  sqlite3_session *pSession,      /* Session object */
+  int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
+  void **ppPatchset               /* OUT: Buffer containing patchset */
+);
+
+/*
+** CAPI3REF: Test if a changeset has recorded any changes.
+**
+** Return non-zero if no changes to attached tables have been recorded by
+** the session object passed as the first argument. Otherwise, if one or
+** more changes have been recorded, return zero.
+**
+** Even if this function returns zero, it is possible that calling
+** [sqlite3session_changeset()] on the session handle may still return a
+** changeset that contains no changes. This can happen when a row in
+** an attached table is modified and then later on the original values
+** are restored. However, if this function returns non-zero, then it is
+** guaranteed that a call to sqlite3session_changeset() will return a
+** changeset containing zero changes.
+*/
+SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Query for the amount of heap memory used by a session object.
+**
+** This API returns the total amount of heap memory in bytes currently
+** used by the session object passed as the only argument.
+*/
+SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);
+
+/*
+** CAPI3REF: Create An Iterator To Traverse A Changeset
+** CONSTRUCTOR: sqlite3_changeset_iter
+**
+** Create an iterator used to iterate through the contents of a changeset.
+** If successful, *pp is set to point to the iterator handle and SQLITE_OK
+** is returned. Otherwise, if an error occurs, *pp is set to zero and an
+** SQLite error code is returned.
+**
+** The following functions can be used to advance and query a changeset
+** iterator created by this function:
+**
+** <ul>
+**   <li> [sqlite3changeset_next()]
+**   <li> [sqlite3changeset_op()]
+**   <li> [sqlite3changeset_new()]
+**   <li> [sqlite3changeset_old()]
+** </ul>
+**
+** It is the responsibility of the caller to eventually destroy the iterator
+** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
+** changeset (pChangeset) must remain valid until after the iterator is
+** destroyed.
+**
+** Assuming the changeset blob was created by one of the
+** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
+** [sqlite3changeset_invert()] functions, all changes within the changeset
+** that apply to a single table are grouped together. This means that when
+** an application iterates through a changeset using an iterator created by
+** this function, all changes that relate to a single table are visited
+** consecutively. There is no chance that the iterator will visit a change
+** the applies to table X, then one for table Y, and then later on visit
+** another change for table X.
+**
+** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
+** may be modified by passing a combination of
+** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
+**
+** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
+** and therefore subject to change.
+*/
+SQLITE_API int sqlite3changeset_start(
+  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
+  int nChangeset,                 /* Size of changeset blob in bytes */
+  void *pChangeset                /* Pointer to blob containing changeset */
+);
+SQLITE_API int sqlite3changeset_start_v2(
+  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
+  int nChangeset,                 /* Size of changeset blob in bytes */
+  void *pChangeset,               /* Pointer to blob containing changeset */
+  int flags                       /* SESSION_CHANGESETSTART_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3changeset_start_v2
+**
+** The following flags may passed via the 4th parameter to
+** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
+**
+** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
+**   Invert the changeset while iterating through it. This is equivalent to
+**   inverting a changeset using sqlite3changeset_invert() before applying it.
+**   It is an error to specify this flag with a patchset.
+*/
+#define SQLITE_CHANGESETSTART_INVERT        0x0002
+
+
+/*
+** CAPI3REF: Advance A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function may only be used with iterators created by the function
+** [sqlite3changeset_start()]. If it is called on an iterator passed to
+** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
+** is returned and the call has no effect.
+**
+** Immediately after an iterator is created by sqlite3changeset_start(), it
+** does not point to any change in the changeset. Assuming the changeset
+** is not empty, the first call to this function advances the iterator to
+** point to the first change in the changeset. Each subsequent call advances
+** the iterator to point to the next change in the changeset (if any). If
+** no error occurs and the iterator points to a valid change after a call
+** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
+** Otherwise, if all changes in the changeset have already been visited,
+** SQLITE_DONE is returned.
+**
+** If an error occurs, an SQLite error code is returned. Possible error
+** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
+** SQLITE_NOMEM.
+*/
+SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
+
+/*
+** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
+** is not the case, this function returns [SQLITE_MISUSE].
+**
+** Arguments pOp, pnCol and pzTab may not be NULL. Upon return, three
+** outputs are set through these pointers:
+**
+** *pOp is set to one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
+** depending on the type of change that the iterator currently points to;
+**
+** *pnCol is set to the number of columns in the table affected by the change; and
+**
+** *pzTab is set to point to a nul-terminated utf-8 encoded string containing
+** the name of the table affected by the current change. The buffer remains
+** valid until either sqlite3changeset_next() is called on the iterator
+** or until the conflict-handler function returns.
+**
+** If pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
+** is an indirect change, or false (0) otherwise. See the documentation for
+** [sqlite3session_indirect()] for a description of direct and indirect
+** changes.
+**
+** If no error occurs, SQLITE_OK is returned. If an error does occur, an
+** SQLite error code is returned. The values of the output variables may not
+** be trusted in this case.
+*/
+SQLITE_API int sqlite3changeset_op(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  const char **pzTab,             /* OUT: Pointer to table name */
+  int *pnCol,                     /* OUT: Number of columns in table */
+  int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
+  int *pbIndirect                 /* OUT: True for an 'indirect' change */
+);
+
+/*
+** CAPI3REF: Obtain The Primary Key Definition Of A Table
+** METHOD: sqlite3_changeset_iter
+**
+** For each modified table, a changeset includes the following:
+**
+** <ul>
+**   <li> The number of columns in the table, and
+**   <li> Which of those columns make up the tables PRIMARY KEY.
+** </ul>
+**
+** This function is used to find which columns comprise the PRIMARY KEY of
+** the table modified by the change that iterator pIter currently points to.
+** If successful, *pabPK is set to point to an array of nCol entries, where
+** nCol is the number of columns in the table. Elements of *pabPK are set to
+** 0x01 if the corresponding column is part of the tables primary key, or
+** 0x00 if it is not.
+**
+** If argument pnCol is not NULL, then *pnCol is set to the number of columns
+** in the table.
+**
+** If this function is called when the iterator does not point to a valid
+** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
+** SQLITE_OK is returned and the output variables populated as described
+** above.
+*/
+SQLITE_API int sqlite3changeset_pk(
+  sqlite3_changeset_iter *pIter,  /* Iterator object */
+  unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
+  int *pnCol                      /* OUT: Number of entries in output array */
+);
+
+/*
+** CAPI3REF: Obtain old.* Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
+** Furthermore, it may only be called if the type of change that the iterator
+** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
+** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the vector of
+** original row values stored as part of the UPDATE or DELETE change and
+** returns SQLITE_OK. The name of the function comes from the fact that this
+** is similar to the "old.*" columns available to update or delete triggers.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_old(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
+);
+
+/*
+** CAPI3REF: Obtain new.* Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** The pIter argument passed to this function may either be an iterator
+** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
+** created by [sqlite3changeset_start()]. In the latter case, the most recent
+** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
+** Furthermore, it may only be called if the type of change that the iterator
+** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
+** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the vector of
+** new row values stored as part of the UPDATE or INSERT change and
+** returns SQLITE_OK. If the change is an UPDATE and does not include
+** a new value for the requested column, *ppValue is set to NULL and
+** SQLITE_OK returned. The name of the function comes from the fact that
+** this is similar to the "new.*" columns available to update or delete
+** triggers.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_new(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
+);
+
+/*
+** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function should only be used with iterator objects passed to a
+** conflict-handler callback by [sqlite3changeset_apply()] with either
+** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
+** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
+** is set to NULL.
+**
+** Argument iVal must be greater than or equal to 0, and less than the number
+** of columns in the table affected by the current change. Otherwise,
+** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
+**
+** If successful, this function sets *ppValue to point to a protected
+** sqlite3_value object containing the iVal'th value from the
+** "conflicting row" associated with the current conflict-handler callback
+** and returns SQLITE_OK.
+**
+** If some other error occurs (e.g. an OOM condition), an SQLite error code
+** is returned and *ppValue is set to NULL.
+*/
+SQLITE_API int sqlite3changeset_conflict(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int iVal,                       /* Column number */
+  sqlite3_value **ppValue         /* OUT: Value from conflicting row */
+);
+
+/*
+** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
+** METHOD: sqlite3_changeset_iter
+**
+** This function may only be called with an iterator passed to an
+** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
+** it sets the output variable to the total number of known foreign key
+** violations in the destination database and returns SQLITE_OK.
+**
+** In all other cases this function returns SQLITE_MISUSE.
+*/
+SQLITE_API int sqlite3changeset_fk_conflicts(
+  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
+  int *pnOut                      /* OUT: Number of FK violations */
+);
+
+
+/*
+** CAPI3REF: Finalize A Changeset Iterator
+** METHOD: sqlite3_changeset_iter
+**
+** This function is used to finalize an iterator allocated with
+** [sqlite3changeset_start()].
+**
+** This function should only be called on iterators created using the
+** [sqlite3changeset_start()] function. If an application calls this
+** function with an iterator passed to a conflict-handler by
+** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
+** call has no effect.
+**
+** If an error was encountered within a call to an sqlite3changeset_xxx()
+** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
+** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
+** to that error is returned by this function. Otherwise, SQLITE_OK is
+** returned. This is to allow the following pattern (pseudo-code):
+**
+** <pre>
+**   sqlite3changeset_start();
+**   while( SQLITE_ROW==sqlite3changeset_next() ){
+**     // Do something with change.
+**   }
+**   rc = sqlite3changeset_finalize();
+**   if( rc!=SQLITE_OK ){
+**     // An error has occurred
+**   }
+** </pre>
+*/
+SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
+
+/*
+** CAPI3REF: Invert A Changeset
+**
+** This function is used to "invert" a changeset object. Applying an inverted
+** changeset to a database reverses the effects of applying the uninverted
+** changeset. Specifically:
+**
+** <ul>
+**   <li> Each DELETE change is changed to an INSERT, and
+**   <li> Each INSERT change is changed to a DELETE, and
+**   <li> For each UPDATE change, the old.* and new.* values are exchanged.
+** </ul>
+**
+** This function does not change the order in which changes appear within
+** the changeset. It merely reverses the sense of each individual change.
+**
+** If successful, a pointer to a buffer containing the inverted changeset
+** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
+** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
+** zeroed and an SQLite error code returned.
+**
+** It is the responsibility of the caller to eventually call sqlite3_free()
+** on the *ppOut pointer to free the buffer allocation following a successful
+** call to this function.
+**
+** WARNING/TODO: This function currently assumes that the input is a valid
+** changeset. If it is not, the results are undefined.
+*/
+SQLITE_API int sqlite3changeset_invert(
+  int nIn, const void *pIn,       /* Input changeset */
+  int *pnOut, void **ppOut        /* OUT: Inverse of input */
+);
+
+/*
+** CAPI3REF: Concatenate Two Changeset Objects
+**
+** This function is used to concatenate two changesets, A and B, into a
+** single changeset. The result is a changeset equivalent to applying
+** changeset A followed by changeset B.
+**
+** This function combines the two input changesets using an
+** sqlite3_changegroup object. Calling it produces similar results as the
+** following code fragment:
+**
+** <pre>
+**   sqlite3_changegroup *pGrp;
+**   rc = sqlite3_changegroup_new(&pGrp);
+**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
+**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
+**   if( rc==SQLITE_OK ){
+**     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
+**   }else{
+**     *ppOut = 0;
+**     *pnOut = 0;
+**   }
+** </pre>
+**
+** Refer to the sqlite3_changegroup documentation below for details.
+*/
+SQLITE_API int sqlite3changeset_concat(
+  int nA,                         /* Number of bytes in buffer pA */
+  void *pA,                       /* Pointer to buffer containing changeset A */
+  int nB,                         /* Number of bytes in buffer pB */
+  void *pB,                       /* Pointer to buffer containing changeset B */
+  int *pnOut,                     /* OUT: Number of bytes in output changeset */
+  void **ppOut                    /* OUT: Buffer containing output changeset */
+);
+
+
+/*
+** CAPI3REF: Upgrade the Schema of a Changeset/Patchset
+*/
+SQLITE_API int sqlite3changeset_upgrade(
+  sqlite3 *db,
+  const char *zDb,
+  int nIn, const void *pIn,       /* Input changeset */
+  int *pnOut, void **ppOut        /* OUT: Inverse of input */
+);
+
+
+
+/*
+** CAPI3REF: Changegroup Handle
+**
+** A changegroup is an object used to combine two or more
+** [changesets] or [patchsets]
+*/
+typedef struct sqlite3_changegroup sqlite3_changegroup;
+
+/*
+** CAPI3REF: Create A New Changegroup Object
+** CONSTRUCTOR: sqlite3_changegroup
+**
+** An sqlite3_changegroup object is used to combine two or more changesets
+** (or patchsets) into a single changeset (or patchset). A single changegroup
+** object may combine changesets or patchsets, but not both. The output is
+** always in the same format as the input.
+**
+** If successful, this function returns SQLITE_OK and populates (*pp) with
+** a pointer to a new sqlite3_changegroup object before returning. The caller
+** should eventually free the returned object using a call to
+** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
+** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
+**
+** The usual usage pattern for an sqlite3_changegroup object is as follows:
+**
+** <ul>
+**   <li> It is created using a call to sqlite3changegroup_new().
+**
+**   <li> Zero or more changesets (or patchsets) are added to the object
+**        by calling sqlite3changegroup_add().
+**
+**   <li> The result of combining all input changesets together is obtained
+**        by the application via a call to sqlite3changegroup_output().
+**
+**   <li> The object is deleted using a call to sqlite3changegroup_delete().
+** </ul>
+**
+** Any number of calls to add() and output() may be made between the calls to
+** new() and delete(), and in any order.
+**
+** As well as the regular sqlite3changegroup_add() and
+** sqlite3changegroup_output() functions, also available are the streaming
+** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
+*/
+SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
+
+/*
+** CAPI3REF: Add a Schema to a Changegroup
+** METHOD: sqlite3_changegroup_schema
+**
+** This method may be used to optionally enforce the rule that the changesets
+** added to the changegroup handle must match the schema of database zDb
+** ("main", "temp", or the name of an attached database). If
+** sqlite3changegroup_add() is called to add a changeset that is not compatible
+** with the configured schema, SQLITE_SCHEMA is returned and the changegroup
+** object is left in an undefined state.
+**
+** A changeset schema is considered compatible with the database schema in
+** the same way as for sqlite3changeset_apply(). Specifically, for each
+** table in the changeset, there exists a database table with:
+**
+** <ul>
+**   <li> The name identified by the changeset, and
+**   <li> at least as many columns as recorded in the changeset, and
+**   <li> the primary key columns in the same position as recorded in
+**        the changeset.
+** </ul>
+**
+** The output of the changegroup object always has the same schema as the
+** database nominated using this function. In cases where changesets passed
+** to sqlite3changegroup_add() have fewer columns than the corresponding table
+** in the database schema, these are filled in using the default column
+** values from the database schema. This makes it possible to combined
+** changesets that have different numbers of columns for a single table
+** within a changegroup, provided that they are otherwise compatible.
+*/
+SQLITE_API int sqlite3changegroup_schema(sqlite3_changegroup*, sqlite3*, const char *zDb);
+
+/*
+** CAPI3REF: Add A Changeset To A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** Add all changes within the changeset (or patchset) in buffer pData (size
+** nData bytes) to the changegroup.
+**
+** If the buffer contains a patchset, then all prior calls to this function
+** on the same changegroup object must also have specified patchsets. Or, if
+** the buffer contains a changeset, so must have the earlier calls to this
+** function. Otherwise, SQLITE_ERROR is returned and no changes are added
+** to the changegroup.
+**
+** Rows within the changeset and changegroup are identified by the values in
+** their PRIMARY KEY columns. A change in the changeset is considered to
+** apply to the same row as a change already present in the changegroup if
+** the two rows have the same primary key.
+**
+** Changes to rows that do not already appear in the changegroup are
+** simply copied into it. Or, if both the new changeset and the changegroup
+** contain changes that apply to a single row, the final contents of the
+** changegroup depends on the type of each change, as follows:
+**
+** <table border=1 style="margin-left:8ex;margin-right:8ex">
+**   <tr><th style="white-space:pre">Existing Change  </th>
+**       <th style="white-space:pre">New Change       </th>
+**       <th>Output Change
+**   <tr><td>INSERT <td>INSERT <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>INSERT <td>UPDATE <td>
+**       The INSERT change remains in the changegroup. The values in the
+**       INSERT change are modified as if the row was inserted by the
+**       existing change and then updated according to the new change.
+**   <tr><td>INSERT <td>DELETE <td>
+**       The existing INSERT is removed from the changegroup. The DELETE is
+**       not added.
+**   <tr><td>UPDATE <td>INSERT <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>UPDATE <td>UPDATE <td>
+**       The existing UPDATE remains within the changegroup. It is amended
+**       so that the accompanying values are as if the row was updated once
+**       by the existing change and then again by the new change.
+**   <tr><td>UPDATE <td>DELETE <td>
+**       The existing UPDATE is replaced by the new DELETE within the
+**       changegroup.
+**   <tr><td>DELETE <td>INSERT <td>
+**       If one or more of the column values in the row inserted by the
+**       new change differ from those in the row deleted by the existing
+**       change, the existing DELETE is replaced by an UPDATE within the
+**       changegroup. Otherwise, if the inserted row is exactly the same
+**       as the deleted row, the existing DELETE is simply discarded.
+**   <tr><td>DELETE <td>UPDATE <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+**   <tr><td>DELETE <td>DELETE <td>
+**       The new change is ignored. This case does not occur if the new
+**       changeset was recorded immediately after the changesets already
+**       added to the changegroup.
+** </table>
+**
+** If the new changeset contains changes to a table that is already present
+** in the changegroup, then the number of columns and the position of the
+** primary key columns for the table must be consistent. If this is not the
+** case, this function fails with SQLITE_SCHEMA. Except, if the changegroup
+** object has been configured with a database schema using the
+** sqlite3changegroup_schema() API, then it is possible to combine changesets
+** with different numbers of columns for a single table, provided that
+** they are otherwise compatible.
+**
+** If the input changeset appears to be corrupt and the corruption is
+** detected, SQLITE_CORRUPT is returned. Or, if an out-of-memory condition
+** occurs during processing, this function returns SQLITE_NOMEM.
+**
+** In all cases, if an error occurs the state of the final contents of the
+** changegroup is undefined. If no error occurs, SQLITE_OK is returned.
+*/
+SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
+
+/*
+** CAPI3REF: Add A Single Change To A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** This function adds the single change currently indicated by the iterator
+** passed as the second argument to the changegroup object. The rules for
+** adding the change are just as described for [sqlite3changegroup_add()].
+**
+** If the change is successfully added to the changegroup, SQLITE_OK is
+** returned. Otherwise, an SQLite error code is returned.
+**
+** The iterator must point to a valid entry when this function is called.
+** If it does not, SQLITE_ERROR is returned and no change is added to the
+** changegroup. Additionally, the iterator must not have been opened with
+** the SQLITE_CHANGESETAPPLY_INVERT flag. In this case SQLITE_ERROR is also
+** returned.
+*/
+SQLITE_API int sqlite3changegroup_add_change(
+  sqlite3_changegroup*,
+  sqlite3_changeset_iter*
+);
+
+
+
+/*
+** CAPI3REF: Obtain A Composite Changeset From A Changegroup
+** METHOD: sqlite3_changegroup
+**
+** Obtain a buffer containing a changeset (or patchset) representing the
+** current contents of the changegroup. If the inputs to the changegroup
+** were themselves changesets, the output is a changeset. Or, if the
+** inputs were patchsets, the output is also a patchset.
+**
+** As with the output of the sqlite3session_changeset() and
+** sqlite3session_patchset() functions, all changes related to a single
+** table are grouped together in the output of this function. Tables appear
+** in the same order as for the very first changeset added to the changegroup.
+** If the second or subsequent changesets added to the changegroup contain
+** changes for tables that do not appear in the first changeset, they are
+** appended onto the end of the output changeset, again in the order in
+** which they are first encountered.
+**
+** If an error occurs, an SQLite error code is returned and the output
+** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
+** is returned and the output variables are set to the size of and a
+** pointer to the output buffer, respectively. In this case it is the
+** responsibility of the caller to eventually free the buffer using a
+** call to sqlite3_free().
+*/
+SQLITE_API int sqlite3changegroup_output(
+  sqlite3_changegroup*,
+  int *pnData,                    /* OUT: Size of output buffer in bytes */
+  void **ppData                   /* OUT: Pointer to output buffer */
+);
+
+/*
+** CAPI3REF: Delete A Changegroup Object
+** DESTRUCTOR: sqlite3_changegroup
+*/
+SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
+
+/*
+** CAPI3REF: Apply A Changeset To A Database
+**
+** Apply a changeset or patchset to a database. These functions attempt to
+** update the "main" database attached to handle db with the changes found in
+** the changeset passed via the second and third arguments.
+**
+** The fourth argument (xFilter) passed to these functions is the "filter
+** callback". If it is not NULL, then for each table affected by at least one
+** change in the changeset, the filter callback is invoked with
+** the table name as the second argument, and a copy of the context pointer
+** passed as the sixth argument as the first. If the "filter callback"
+** returns zero, then no attempt is made to apply any changes to the table.
+** Otherwise, if the return value is non-zero or the xFilter argument to
+** is NULL, all changes related to the table are attempted.
+**
+** For each table that is not excluded by the filter callback, this function
+** tests that the target database contains a compatible table. A table is
+** considered compatible if all of the following are true:
+**
+** <ul>
+**   <li> The table has the same name as the name recorded in the
+**        changeset, and
+**   <li> The table has at least as many columns as recorded in the
+**        changeset, and
+**   <li> The table has primary key columns in the same position as
+**        recorded in the changeset.
+** </ul>
+**
+** If there is no compatible table, it is not an error, but none of the
+** changes associated with the table are applied. A warning message is issued
+** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
+** one such warning is issued for each table in the changeset.
+**
+** For each change for which there is a compatible table, an attempt is made
+** to modify the table contents according to the UPDATE, INSERT or DELETE
+** change. If a change cannot be applied cleanly, the conflict handler
+** function passed as the fifth argument to sqlite3changeset_apply() may be
+** invoked. A description of exactly when the conflict handler is invoked for
+** each type of change is below.
+**
+** Unlike the xFilter argument, xConflict may not be passed NULL. The results
+** of passing anything other than a valid function pointer as the xConflict
+** argument are undefined.
+**
+** Each time the conflict handler function is invoked, it must return one
+** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
+** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
+** if the second argument passed to the conflict handler is either
+** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
+** returns an illegal value, any changes already made are rolled back and
+** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
+** actions are taken by sqlite3changeset_apply() depending on the value
+** returned by each invocation of the conflict-handler function. Refer to
+** the documentation for the three
+** [SQLITE_CHANGESET_OMIT|available return values] for details.
+**
+** <dl>
+** <dt>DELETE Changes<dd>
+**   For each DELETE change, the function checks if the target database
+**   contains a row with the same primary key value (or values) as the
+**   original row values stored in the changeset. If it does, and the values
+**   stored in all non-primary key columns also match the values stored in
+**   the changeset the row is deleted from the target database.
+**
+**   If a row with matching primary key values is found, but one or more of
+**   the non-primary key fields contains a value different from the original
+**   row value stored in the changeset, the conflict-handler function is
+**   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
+**   database table has more columns than are recorded in the changeset,
+**   only the values of those non-primary key fields are compared against
+**   the current database contents - any trailing database table columns
+**   are ignored.
+**
+**   If no row with matching primary key values is found in the database,
+**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
+**   passed as the second argument.
+**
+**   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
+**   (which can only happen if a foreign key constraint is violated), the
+**   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
+**   passed as the second argument. This includes the case where the DELETE
+**   operation is attempted because an earlier call to the conflict handler
+**   function returned [SQLITE_CHANGESET_REPLACE].
+**
+** <dt>INSERT Changes<dd>
+**   For each INSERT change, an attempt is made to insert the new row into
+**   the database. If the changeset row contains fewer fields than the
+**   database table, the trailing fields are populated with their default
+**   values.
+**
+**   If the attempt to insert the row fails because the database already
+**   contains a row with the same primary key values, the conflict handler
+**   function is invoked with the second argument set to
+**   [SQLITE_CHANGESET_CONFLICT].
+**
+**   If the attempt to insert the row fails because of some other constraint
+**   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
+**   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
+**   This includes the case where the INSERT operation is re-attempted because
+**   an earlier call to the conflict handler function returned
+**   [SQLITE_CHANGESET_REPLACE].
+**
+** <dt>UPDATE Changes<dd>
+**   For each UPDATE change, the function checks if the target database
+**   contains a row with the same primary key value (or values) as the
+**   original row values stored in the changeset. If it does, and the values
+**   stored in all modified non-primary key columns also match the values
+**   stored in the changeset the row is updated within the target database.
+**
+**   If a row with matching primary key values is found, but one or more of
+**   the modified non-primary key fields contains a value different from an
+**   original row value stored in the changeset, the conflict-handler function
+**   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
+**   UPDATE changes only contain values for non-primary key fields that are
+**   to be modified, only those fields need to match the original values to
+**   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
+**
+**   If no row with matching primary key values is found in the database,
+**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
+**   passed as the second argument.
+**
+**   If the UPDATE operation is attempted, but SQLite returns
+**   SQLITE_CONSTRAINT, the conflict-handler function is invoked with
+**   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
+**   This includes the case where the UPDATE operation is attempted after
+**   an earlier call to the conflict handler function returned
+**   [SQLITE_CHANGESET_REPLACE].
+** </dl>
+**
+** It is safe to execute SQL statements, including those that write to the
+** table that the callback related to, from within the xConflict callback.
+** This can be used to further customize the application's conflict
+** resolution strategy.
+**
+** All changes made by these functions are enclosed in a savepoint transaction.
+** If any other error (aside from a constraint failure when attempting to
+** write to the target database) occurs, then the savepoint transaction is
+** rolled back, restoring the target database to its original state, and an
+** SQLite error code returned.
+**
+** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
+** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
+** may set (*ppRebase) to point to a "rebase" that may be used with the
+** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
+** is set to the size of the buffer in bytes. It is the responsibility of the
+** caller to eventually free any such buffer using sqlite3_free(). The buffer
+** is only allocated and populated if one or more conflicts were encountered
+** while applying the patchset. See comments surrounding the sqlite3_rebaser
+** APIs for further details.
+**
+** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
+** may be modified by passing a combination of
+** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
+**
+** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
+** and therefore subject to change.
+*/
+SQLITE_API int sqlite3changeset_apply(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+);
+SQLITE_API int sqlite3changeset_apply_v2(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int nChangeset,                 /* Size of changeset in bytes */
+  void *pChangeset,               /* Changeset blob */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase, /* OUT: Rebase data */
+  int flags                       /* SESSION_CHANGESETAPPLY_* flags */
+);
+
+/*
+** CAPI3REF: Flags for sqlite3changeset_apply_v2
+**
+** The following flags may passed via the 9th parameter to
+** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
+**
+** <dl>
+** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
+**   Usually, the sessions module encloses all operations performed by
+**   a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
+**   SAVEPOINT is committed if the changeset or patchset is successfully
+**   applied, or rolled back if an error occurs. Specifying this flag
+**   causes the sessions module to omit this savepoint. In this case, if the
+**   caller has an open transaction or savepoint when apply_v2() is called,
+**   it may revert the partially applied changeset by rolling it back.
+**
+** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
+**   Invert the changeset before applying it. This is equivalent to inverting
+**   a changeset using sqlite3changeset_invert() before applying it. It is
+**   an error to specify this flag with a patchset.
+**
+** <dt>SQLITE_CHANGESETAPPLY_IGNORENOOP <dd>
+**   Do not invoke the conflict handler callback for any changes that
+**   would not actually modify the database even if they were applied.
+**   Specifically, this means that the conflict handler is not invoked
+**   for:
+**    <ul>
+**    <li>a delete change if the row being deleted cannot be found,
+**    <li>an update change if the modified fields are already set to
+**        their new values in the conflicting row, or
+**    <li>an insert change if all fields of the conflicting row match
+**        the row being inserted.
+**    </ul>
+**
+** <dt>SQLITE_CHANGESETAPPLY_FKNOACTION <dd>
+**   If this flag it set, then all foreign key constraints in the target
+**   database behave as if they were declared with "ON UPDATE NO ACTION ON
+**   DELETE NO ACTION", even if they are actually CASCADE, RESTRICT, SET NULL
+**   or SET DEFAULT.
+*/
+#define SQLITE_CHANGESETAPPLY_NOSAVEPOINT   0x0001
+#define SQLITE_CHANGESETAPPLY_INVERT        0x0002
+#define SQLITE_CHANGESETAPPLY_IGNORENOOP    0x0004
+#define SQLITE_CHANGESETAPPLY_FKNOACTION    0x0008
+
+/*
+** CAPI3REF: Constants Passed To The Conflict Handler
+**
+** Values that may be passed as the second argument to a conflict-handler.
+**
+** <dl>
+** <dt>SQLITE_CHANGESET_DATA<dd>
+**   The conflict handler is invoked with CHANGESET_DATA as the second argument
+**   when processing a DELETE or UPDATE change if a row with the required
+**   PRIMARY KEY fields is present in the database, but one or more other
+**   (non primary-key) fields modified by the update do not contain the
+**   expected "before" values.
+**
+**   The conflicting row, in this case, is the database row with the matching
+**   primary key.
+**
+** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
+**   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
+**   argument when processing a DELETE or UPDATE change if a row with the
+**   required PRIMARY KEY fields is not present in the database.
+**
+**   There is no conflicting row in this case. The results of invoking the
+**   sqlite3changeset_conflict() API are undefined.
+**
+** <dt>SQLITE_CHANGESET_CONFLICT<dd>
+**   CHANGESET_CONFLICT is passed as the second argument to the conflict
+**   handler while processing an INSERT change if the operation would result
+**   in duplicate primary key values.
+**
+**   The conflicting row in this case is the database row with the matching
+**   primary key.
+**
+** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
+**   If foreign key handling is enabled, and applying a changeset leaves the
+**   database in a state containing foreign key violations, the conflict
+**   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
+**   exactly once before the changeset is committed. If the conflict handler
+**   returns CHANGESET_OMIT, the changes, including those that caused the
+**   foreign key constraint violation, are committed. Or, if it returns
+**   CHANGESET_ABORT, the changeset is rolled back.
+**
+**   No current or conflicting row information is provided. The only function
+**   it is possible to call on the supplied sqlite3_changeset_iter handle
+**   is sqlite3changeset_fk_conflicts().
+**
+** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
+**   If any other constraint violation occurs while applying a change (i.e.
+**   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
+**   invoked with CHANGESET_CONSTRAINT as the second argument.
+**
+**   There is no conflicting row in this case. The results of invoking the
+**   sqlite3changeset_conflict() API are undefined.
+**
+** </dl>
+*/
+#define SQLITE_CHANGESET_DATA        1
+#define SQLITE_CHANGESET_NOTFOUND    2
+#define SQLITE_CHANGESET_CONFLICT    3
+#define SQLITE_CHANGESET_CONSTRAINT  4
+#define SQLITE_CHANGESET_FOREIGN_KEY 5
+
+/*
+** CAPI3REF: Constants Returned By The Conflict Handler
+**
+** A conflict handler callback must return one of the following three values.
+**
+** <dl>
+** <dt>SQLITE_CHANGESET_OMIT<dd>
+**   If a conflict handler returns this value no special action is taken. The
+**   change that caused the conflict is not applied. The session module
+**   continues to the next change in the changeset.
+**
+** <dt>SQLITE_CHANGESET_REPLACE<dd>
+**   This value may only be returned if the second argument to the conflict
+**   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
+**   is not the case, any changes applied so far are rolled back and the
+**   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
+**
+**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
+**   handler, then the conflicting row is either updated or deleted, depending
+**   on the type of change.
+**
+**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
+**   handler, then the conflicting row is removed from the database and a
+**   second attempt to apply the change is made. If this second attempt fails,
+**   the original row is restored to the database before continuing.
+**
+** <dt>SQLITE_CHANGESET_ABORT<dd>
+**   If this value is returned, any changes applied so far are rolled back
+**   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
+** </dl>
+*/
+#define SQLITE_CHANGESET_OMIT       0
+#define SQLITE_CHANGESET_REPLACE    1
+#define SQLITE_CHANGESET_ABORT      2
+
+/*
+** CAPI3REF: Rebasing changesets
+** EXPERIMENTAL
+**
+** Suppose there is a site hosting a database in state S0. And that
+** modifications are made that move that database to state S1 and a
+** changeset recorded (the "local" changeset). Then, a changeset based
+** on S0 is received from another site (the "remote" changeset) and
+** applied to the database. The database is then in state
+** (S1+"remote"), where the exact state depends on any conflict
+** resolution decisions (OMIT or REPLACE) made while applying "remote".
+** Rebasing a changeset is to update it to take those conflict
+** resolution decisions into account, so that the same conflicts
+** do not have to be resolved elsewhere in the network.
+**
+** For example, if both the local and remote changesets contain an
+** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
+**
+**   local:  INSERT INTO t1 VALUES(1, 'v1');
+**   remote: INSERT INTO t1 VALUES(1, 'v2');
+**
+** and the conflict resolution is REPLACE, then the INSERT change is
+** removed from the local changeset (it was overridden). Or, if the
+** conflict resolution was "OMIT", then the local changeset is modified
+** to instead contain:
+**
+**           UPDATE t1 SET b = 'v2' WHERE a=1;
+**
+** Changes within the local changeset are rebased as follows:
+**
+** <dl>
+** <dt>Local INSERT<dd>
+**   This may only conflict with a remote INSERT. If the conflict
+**   resolution was OMIT, then add an UPDATE change to the rebased
+**   changeset. Or, if the conflict resolution was REPLACE, add
+**   nothing to the rebased changeset.
+**
+** <dt>Local DELETE<dd>
+**   This may conflict with a remote UPDATE or DELETE. In both cases the
+**   only possible resolution is OMIT. If the remote operation was a
+**   DELETE, then add no change to the rebased changeset. If the remote
+**   operation was an UPDATE, then the old.* fields of change are updated
+**   to reflect the new.* values in the UPDATE.
+**
+** <dt>Local UPDATE<dd>
+**   This may conflict with a remote UPDATE or DELETE. If it conflicts
+**   with a DELETE, and the conflict resolution was OMIT, then the update
+**   is changed into an INSERT. Any undefined values in the new.* record
+**   from the update change are filled in using the old.* values from
+**   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
+**   the UPDATE change is simply omitted from the rebased changeset.
+**
+**   If conflict is with a remote UPDATE and the resolution is OMIT, then
+**   the old.* values are rebased using the new.* values in the remote
+**   change. Or, if the resolution is REPLACE, then the change is copied
+**   into the rebased changeset with updates to columns also updated by
+**   the conflicting remote UPDATE removed. If this means no columns would
+**   be updated, the change is omitted.
+** </dl>
+**
+** A local change may be rebased against multiple remote changes
+** simultaneously. If a single key is modified by multiple remote
+** changesets, they are combined as follows before the local changeset
+** is rebased:
+**
+** <ul>
+**    <li> If there has been one or more REPLACE resolutions on a
+**         key, it is rebased according to a REPLACE.
+**
+**    <li> If there have been no REPLACE resolutions on a key, then
+**         the local changeset is rebased according to the most recent
+**         of the OMIT resolutions.
+** </ul>
+**
+** Note that conflict resolutions from multiple remote changesets are
+** combined on a per-field basis, not per-row. This means that in the
+** case of multiple remote UPDATE operations, some fields of a single
+** local change may be rebased for REPLACE while others are rebased for
+** OMIT.
+**
+** In order to rebase a local changeset, the remote changeset must first
+** be applied to the local database using sqlite3changeset_apply_v2() and
+** the buffer of rebase information captured. Then:
+**
+** <ol>
+**   <li> An sqlite3_rebaser object is created by calling
+**        sqlite3rebaser_create().
+**   <li> The new object is configured with the rebase buffer obtained from
+**        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
+**        If the local changeset is to be rebased against multiple remote
+**        changesets, then sqlite3rebaser_configure() should be called
+**        multiple times, in the same order that the multiple
+**        sqlite3changeset_apply_v2() calls were made.
+**   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
+**   <li> The sqlite3_rebaser object is deleted by calling
+**        sqlite3rebaser_delete().
+** </ol>
+*/
+typedef struct sqlite3_rebaser sqlite3_rebaser;
+
+/*
+** CAPI3REF: Create a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
+** point to the new object and return SQLITE_OK. Otherwise, if an error
+** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
+** to NULL.
+*/
+SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
+
+/*
+** CAPI3REF: Configure a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Configure the changeset rebaser object to rebase changesets according
+** to the conflict resolutions described by buffer pRebase (size nRebase
+** bytes), which must have been obtained from a previous call to
+** sqlite3changeset_apply_v2().
+*/
+SQLITE_API int sqlite3rebaser_configure(
+  sqlite3_rebaser*,
+  int nRebase, const void *pRebase
+);
+
+/*
+** CAPI3REF: Rebase a changeset
+** EXPERIMENTAL
+**
+** Argument pIn must point to a buffer containing a changeset nIn bytes
+** in size. This function allocates and populates a buffer with a copy
+** of the changeset rebased according to the configuration of the
+** rebaser object passed as the first argument. If successful, (*ppOut)
+** is set to point to the new buffer containing the rebased changeset and
+** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
+** responsibility of the caller to eventually free the new buffer using
+** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
+** are set to zero and an SQLite error code returned.
+*/
+SQLITE_API int sqlite3rebaser_rebase(
+  sqlite3_rebaser*,
+  int nIn, const void *pIn,
+  int *pnOut, void **ppOut
+);
+
+/*
+** CAPI3REF: Delete a changeset rebaser object.
+** EXPERIMENTAL
+**
+** Delete the changeset rebaser object and all associated resources. There
+** should be one call to this function for each successful invocation
+** of sqlite3rebaser_create().
+*/
+SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
+
+/*
+** CAPI3REF: Streaming Versions of API functions.
+**
+** The six streaming API xxx_strm() functions serve similar purposes to the
+** corresponding non-streaming API functions:
+**
+** <table border=1 style="margin-left:8ex;margin-right:8ex">
+**   <tr><th>Streaming function<th>Non-streaming equivalent</th>
+**   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
+**   <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
+**   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
+**   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
+**   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
+**   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
+**   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
+** </table>
+**
+** Non-streaming functions that accept changesets (or patchsets) as input
+** require that the entire changeset be stored in a single buffer in memory.
+** Similarly, those that return a changeset or patchset do so by returning
+** a pointer to a single large buffer allocated using sqlite3_malloc().
+** Normally this is convenient. However, if an application running in a
+** low-memory environment is required to handle very large changesets, the
+** large contiguous memory allocations required can become onerous.
+**
+** In order to avoid this problem, instead of a single large buffer, input
+** is passed to a streaming API functions by way of a callback function that
+** the sessions module invokes to incrementally request input data as it is
+** required. In all cases, a pair of API function parameters such as
+**
+**  <pre>
+**        int nChangeset,
+**        void *pChangeset,
+**  </pre>
+**
+** Is replaced by:
+**
+**  <pre>
+**        int (*xInput)(void *pIn, void *pData, int *pnData),
+**        void *pIn,
+**  </pre>
+**
+** Each time the xInput callback is invoked by the sessions module, the first
+** argument passed is a copy of the supplied pIn context pointer. The second
+** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
+** error occurs the xInput method should copy up to (*pnData) bytes of data
+** into the buffer and set (*pnData) to the actual number of bytes copied
+** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
+** should be set to zero to indicate this. Or, if an error occurs, an SQLite
+** error code should be returned. In all cases, if an xInput callback returns
+** an error, all processing is abandoned and the streaming API function
+** returns a copy of the error code to the caller.
+**
+** In the case of sqlite3changeset_start_strm(), the xInput callback may be
+** invoked by the sessions module at any point during the lifetime of the
+** iterator. If such an xInput callback returns an error, the iterator enters
+** an error state, whereby all subsequent calls to iterator functions
+** immediately fail with the same error code as returned by xInput.
+**
+** Similarly, streaming API functions that return changesets (or patchsets)
+** return them in chunks by way of a callback function instead of via a
+** pointer to a single large buffer. In this case, a pair of parameters such
+** as:
+**
+**  <pre>
+**        int *pnChangeset,
+**        void **ppChangeset,
+**  </pre>
+**
+** Is replaced by:
+**
+**  <pre>
+**        int (*xOutput)(void *pOut, const void *pData, int nData),
+**        void *pOut
+**  </pre>
+**
+** The xOutput callback is invoked zero or more times to return data to
+** the application. The first parameter passed to each call is a copy of the
+** pOut pointer supplied by the application. The second parameter, pData,
+** points to a buffer nData bytes in size containing the chunk of output
+** data being returned. If the xOutput callback successfully processes the
+** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
+** it should return some other SQLite error code. In this case processing
+** is immediately abandoned and the streaming API function returns a copy
+** of the xOutput error code to the application.
+**
+** The sessions module never invokes an xOutput callback with the third
+** parameter set to a value less than or equal to zero. Other than this,
+** no guarantees are made as to the size of the chunks of data returned.
+*/
+SQLITE_API int sqlite3changeset_apply_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx                      /* First argument passed to xConflict */
+);
+SQLITE_API int sqlite3changeset_apply_v2_strm(
+  sqlite3 *db,                    /* Apply change to "main" db of this handle */
+  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
+  void *pIn,                                          /* First arg for xInput */
+  int(*xFilter)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    const char *zTab              /* Table name */
+  ),
+  int(*xConflict)(
+    void *pCtx,                   /* Copy of sixth arg to _apply() */
+    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
+    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
+  ),
+  void *pCtx,                     /* First argument passed to xConflict */
+  void **ppRebase, int *pnRebase,
+  int flags
+);
+SQLITE_API int sqlite3changeset_concat_strm(
+  int (*xInputA)(void *pIn, void *pData, int *pnData),
+  void *pInA,
+  int (*xInputB)(void *pIn, void *pData, int *pnData),
+  void *pInB,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changeset_invert_strm(
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changeset_start_strm(
+  sqlite3_changeset_iter **pp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn
+);
+SQLITE_API int sqlite3changeset_start_v2_strm(
+  sqlite3_changeset_iter **pp,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int flags
+);
+SQLITE_API int sqlite3session_changeset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3session_patchset_strm(
+  sqlite3_session *pSession,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
+    int (*xInput)(void *pIn, void *pData, int *pnData),
+    void *pIn
+);
+SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
+    int (*xOutput)(void *pOut, const void *pData, int nData),
+    void *pOut
+);
+SQLITE_API int sqlite3rebaser_rebase_strm(
+  sqlite3_rebaser *pRebaser,
+  int (*xInput)(void *pIn, void *pData, int *pnData),
+  void *pIn,
+  int (*xOutput)(void *pOut, const void *pData, int nData),
+  void *pOut
+);
+
+/*
+** CAPI3REF: Configure global parameters
+**
+** The sqlite3session_config() interface is used to make global configuration
+** changes to the sessions module in order to tune it to the specific needs
+** of the application.
+**
+** The sqlite3session_config() interface is not threadsafe. If it is invoked
+** while any other thread is inside any other sessions method then the
+** results are undefined. Furthermore, if it is invoked after any sessions
+** related objects have been created, the results are also undefined.
+**
+** The first argument to the sqlite3session_config() function must be one
+** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
+** interpretation of the (void*) value passed as the second parameter and
+** the effect of calling this function depends on the value of the first
+** parameter.
+**
+** <dl>
+** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
+**    By default, the sessions module streaming interfaces attempt to input
+**    and output data in approximately 1 KiB chunks. This operand may be used
+**    to set and query the value of this configuration setting. The pointer
+**    passed as the second argument must point to a value of type (int).
+**    If this value is greater than 0, it is used as the new streaming data
+**    chunk size for both input and output. Before returning, the (int) value
+**    pointed to by pArg is set to the final value of the streaming interface
+**    chunk size.
+** </dl>
+**
+** This function returns SQLITE_OK if successful, or an SQLite error code
+** otherwise.
+*/
+SQLITE_API int sqlite3session_config(int op, void *pArg);
+
+/*
+** CAPI3REF: Values for sqlite3session_config().
+*/
+#define SQLITE_SESSION_CONFIG_STRMSIZE 1
+
+/*
+** Make sure we can call this stuff from C++.
+*/
+#ifdef __cplusplus
+}
+#endif
+
+#endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
+
+/******** End of sqlite3session.h *********/
+/******** Begin file fts5.h *********/
+/*
+** 2014 May 31
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** Interfaces to extend FTS5. Using the interfaces defined in this file,
+** FTS5 may be extended with:
+**
+**     * custom tokenizers, and
+**     * custom auxiliary functions.
+*/
+
+
+#ifndef _FTS5_H
+#define _FTS5_H
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*************************************************************************
+** CUSTOM AUXILIARY FUNCTIONS
+**
+** Virtual table implementations may overload SQL functions by implementing
+** the sqlite3_module.xFindFunction() method.
+*/
+
+typedef struct Fts5ExtensionApi Fts5ExtensionApi;
+typedef struct Fts5Context Fts5Context;
+typedef struct Fts5PhraseIter Fts5PhraseIter;
+
+typedef void (*fts5_extension_function)(
+  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
+  Fts5Context *pFts,              /* First arg to pass to pApi functions */
+  sqlite3_context *pCtx,          /* Context for returning result/error */
+  int nVal,                       /* Number of values in apVal[] array */
+  sqlite3_value **apVal           /* Array of trailing arguments */
+);
+
+struct Fts5PhraseIter {
+  const unsigned char *a;
+  const unsigned char *b;
+};
+
+/*
+** EXTENSION API FUNCTIONS
+**
+** xUserData(pFts):
+**   Return a copy of the pUserData pointer passed to the xCreateFunction()
+**   API when the extension function was registered.
+**
+** xColumnTotalSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the FTS5 table. Or, if iCol is
+**   non-negative but less than the number of columns in the table, return
+**   the total number of tokens in column iCol, considering all rows in
+**   the FTS5 table.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+** xColumnCount(pFts):
+**   Return the number of columns in the table.
+**
+** xColumnSize(pFts, iCol, pnToken):
+**   If parameter iCol is less than zero, set output variable *pnToken
+**   to the total number of tokens in the current row. Or, if iCol is
+**   non-negative but less than the number of columns in the table, set
+**   *pnToken to the number of tokens in column iCol of the current row.
+**
+**   If parameter iCol is greater than or equal to the number of columns
+**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
+**   an OOM condition or IO error), an appropriate SQLite error code is
+**   returned.
+**
+**   This function may be quite inefficient if used with an FTS5 table
+**   created with the "columnsize=0" option.
+**
+** xColumnText:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the text of column iCol of
+**   the current document. If successful, (*pz) is set to point to a buffer
+**   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
+**   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
+**   if an error occurs, an SQLite error code is returned and the final values
+**   of (*pz) and (*pn) are undefined.
+**
+** xPhraseCount:
+**   Returns the number of phrases in the current query expression.
+**
+** xPhraseSize:
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of phrases in the current query, as returned by xPhraseCount,
+**   0 is returned. Otherwise, this function returns the number of tokens in
+**   phrase iPhrase of the query. Phrases are numbered starting from zero.
+**
+** xInstCount:
+**   Set *pnInst to the total number of occurrences of all phrases within
+**   the query within the current row. Return SQLITE_OK if successful, or
+**   an error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always returns 0.
+**
+** xInst:
+**   Query for the details of phrase match iIdx within the current row.
+**   Phrase matches are numbered starting from zero, so the iIdx argument
+**   should be greater than or equal to zero and smaller than the value
+**   output by xInstCount(). If iIdx is less than zero or greater than
+**   or equal to the value returned by xInstCount(), SQLITE_RANGE is returned.
+**
+**   Otherwise, output parameter *piPhrase is set to the phrase number, *piCol
+**   to the column in which it occurs and *piOff the token offset of the
+**   first token of the phrase. SQLITE_OK is returned if successful, or an
+**   error code (i.e. SQLITE_NOMEM) if an error occurs.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xRowid:
+**   Returns the rowid of the current row.
+**
+** xTokenize:
+**   Tokenize text using the tokenizer belonging to the FTS5 table.
+**
+** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
+**   This API function is used to query the FTS table for phrase iPhrase
+**   of the current query. Specifically, a query equivalent to:
+**
+**       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
+**
+**   with $p set to a phrase equivalent to the phrase iPhrase of the
+**   current query is executed. Any column filter that applies to
+**   phrase iPhrase of the current query is included in $p. For each
+**   row visited, the callback function passed as the fourth argument
+**   is invoked. The context and API objects passed to the callback
+**   function may be used to access the properties of each matched row.
+**   Invoking Api.xUserData() returns a copy of the pointer passed as
+**   the third argument to pUserData.
+**
+**   If parameter iPhrase is less than zero, or greater than or equal to
+**   the number of phrases in the query, as returned by xPhraseCount(),
+**   this function returns SQLITE_RANGE.
+**
+**   If the callback function returns any value other than SQLITE_OK, the
+**   query is abandoned and the xQueryPhrase function returns immediately.
+**   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
+**   Otherwise, the error code is propagated upwards.
+**
+**   If the query runs to completion without incident, SQLITE_OK is returned.
+**   Or, if some error occurs before the query completes or is aborted by
+**   the callback, an SQLite error code is returned.
+**
+**
+** xSetAuxdata(pFts5, pAux, xDelete)
+**
+**   Save the pointer passed as the second argument as the extension function's
+**   "auxiliary data". The pointer may then be retrieved by the current or any
+**   future invocation of the same fts5 extension function made as part of
+**   the same MATCH query using the xGetAuxdata() API.
+**
+**   Each extension function is allocated a single auxiliary data slot for
+**   each FTS query (MATCH expression). If the extension function is invoked
+**   more than once for a single FTS query, then all invocations share a
+**   single auxiliary data context.
+**
+**   If there is already an auxiliary data pointer when this function is
+**   invoked, then it is replaced by the new pointer. If an xDelete callback
+**   was specified along with the original pointer, it is invoked at this
+**   point.
+**
+**   The xDelete callback, if one is specified, is also invoked on the
+**   auxiliary data pointer after the FTS5 query has finished.
+**
+**   If an error (e.g. an OOM condition) occurs within this function,
+**   the auxiliary data is set to NULL and an error code returned. If the
+**   xDelete parameter was not NULL, it is invoked on the auxiliary data
+**   pointer before returning.
+**
+**
+** xGetAuxdata(pFts5, bClear)
+**
+**   Returns the current auxiliary data pointer for the fts5 extension
+**   function. See the xSetAuxdata() method for details.
+**
+**   If the bClear argument is non-zero, then the auxiliary data is cleared
+**   (set to NULL) before this function returns. In this case the xDelete,
+**   if any, is not invoked.
+**
+**
+** xRowCount(pFts5, pnRow)
+**
+**   This function is used to retrieve the total number of rows in the table.
+**   In other words, the same value that would be returned by:
+**
+**        SELECT count(*) FROM ftstable;
+**
+** xPhraseFirst()
+**   This function is used, along with type Fts5PhraseIter and the xPhraseNext
+**   method, to iterate through all instances of a single query phrase within
+**   the current row. This is the same information as is accessible via the
+**   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
+**   to use, this API may be faster under some circumstances. To iterate
+**   through instances of phrase iPhrase, use the following code:
+**
+**       Fts5PhraseIter iter;
+**       int iCol, iOff;
+**       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
+**           iCol>=0;
+**           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
+**       ){
+**         // An instance of phrase iPhrase at offset iOff of column iCol
+**       }
+**
+**   The Fts5PhraseIter structure is defined above. Applications should not
+**   modify this structure directly - it should only be used as shown above
+**   with the xPhraseFirst() and xPhraseNext() API methods (and by
+**   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option. If the FTS5 table is created
+**   with either "detail=none" or "detail=column" and "content=" option
+**   (i.e. if it is a contentless table), then this API always iterates
+**   through an empty set (all calls to xPhraseFirst() set iCol to -1).
+**
+**   In all cases, matches are visited in (column ASC, offset ASC) order.
+**   i.e. all those in column 0, sorted by offset, followed by those in
+**   column 1, etc.
+**
+** xPhraseNext()
+**   See xPhraseFirst above.
+**
+** xPhraseFirstColumn()
+**   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
+**   and xPhraseNext() APIs described above. The difference is that instead
+**   of iterating through all instances of a phrase in the current row, these
+**   APIs are used to iterate through the set of columns in the current row
+**   that contain one or more instances of a specified phrase. For example:
+**
+**       Fts5PhraseIter iter;
+**       int iCol;
+**       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
+**           iCol>=0;
+**           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
+**       ){
+**         // Column iCol contains at least one instance of phrase iPhrase
+**       }
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" option. If the FTS5 table is created with either
+**   "detail=none" "content=" option (i.e. if it is a contentless table),
+**   then this API always iterates through an empty set (all calls to
+**   xPhraseFirstColumn() set iCol to -1).
+**
+**   The information accessed using this API and its companion
+**   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
+**   (or xInst/xInstCount). The chief advantage of this API is that it is
+**   significantly more efficient than those alternatives when used with
+**   "detail=column" tables.
+**
+** xPhraseNextColumn()
+**   See xPhraseFirstColumn above.
+**
+** xQueryToken(pFts5, iPhrase, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase iPhrase of the current
+**   query. Before returning, output parameter *ppToken is set to point
+**   to a buffer containing the requested token, and *pnToken to the
+**   size of this buffer in bytes.
+**
+**   If iPhrase or iToken are less than zero, or if iPhrase is greater than
+**   or equal to the number of phrases in the query as reported by
+**   xPhraseCount(), or if iToken is equal to or greater than the number of
+**   tokens in the phrase, SQLITE_RANGE is returned and *ppToken and *pnToken
+     are both zeroed.
+**
+**   The output text is not a copy of the query text that specified the
+**   token. It is the output of the tokenizer module. For tokendata=1
+**   tables, this includes any embedded 0x00 and trailing data.
+**
+** xInstToken(pFts5, iIdx, iToken, ppToken, pnToken)
+**   This is used to access token iToken of phrase hit iIdx within the
+**   current row. If iIdx is less than zero or greater than or equal to the
+**   value returned by xInstCount(), SQLITE_RANGE is returned.  Otherwise,
+**   output variable (*ppToken) is set to point to a buffer containing the
+**   matching document token, and (*pnToken) to the size of that buffer in
+**   bytes.
+**
+**   The output text is not a copy of the document text that was tokenized.
+**   It is the output of the tokenizer module. For tokendata=1 tables, this
+**   includes any embedded 0x00 and trailing data.
+**
+**   This API may be slow in some cases if the token identified by parameters
+**   iIdx and iToken matched a prefix token in the query. In most cases, the
+**   first call to this API for each prefix token in the query is forced
+**   to scan the portion of the full-text index that matches the prefix
+**   token to collect the extra data required by this API. If the prefix
+**   token matches a large number of token instances in the document set,
+**   this may be a performance problem.
+**
+**   If the user knows in advance that a query may use this API for a
+**   prefix token, FTS5 may be configured to collect all required data as part
+**   of the initial querying of the full-text index, avoiding the second scan
+**   entirely. This also causes prefix queries that do not use this API to
+**   run more slowly and use more memory. FTS5 may be configured in this way
+**   either on a per-table basis using the [FTS5 insttoken | 'insttoken']
+**   option, or on a per-query basis using the
+**   [fts5_insttoken | fts5_insttoken()] user function.
+**
+**   This API can be quite slow if used with an FTS5 table created with the
+**   "detail=none" or "detail=column" option.
+**
+** xColumnLocale(pFts5, iIdx, pzLocale, pnLocale)
+**   If parameter iCol is less than zero, or greater than or equal to the
+**   number of columns in the table, SQLITE_RANGE is returned.
+**
+**   Otherwise, this function attempts to retrieve the locale associated
+**   with column iCol of the current row. Usually, there is no associated
+**   locale, and output parameters (*pzLocale) and (*pnLocale) are set
+**   to NULL and 0, respectively. However, if the fts5_locale() function
+**   was used to associate a locale with the value when it was inserted
+**   into the fts5 table, then (*pzLocale) is set to point to a nul-terminated
+**   buffer containing the name of the locale in utf-8 encoding. (*pnLocale)
+**   is set to the size in bytes of the buffer, not including the
+**   nul-terminator.
+**
+**   If successful, SQLITE_OK is returned. Or, if an error occurs, an
+**   SQLite error code is returned. The final value of the output parameters
+**   is undefined in this case.
+**
+** xTokenize_v2:
+**   Tokenize text using the tokenizer belonging to the FTS5 table. This
+**   API is the same as the xTokenize() API, except that it allows a tokenizer
+**   locale to be specified.
+*/
+struct Fts5ExtensionApi {
+  int iVersion;                   /* Currently always set to 4 */
+
+  void *(*xUserData)(Fts5Context*);
+
+  int (*xColumnCount)(Fts5Context*);
+  int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
+  int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
+
+  int (*xTokenize)(Fts5Context*,
+    const char *pText, int nText, /* Text to tokenize */
+    void *pCtx,                   /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+
+  int (*xPhraseCount)(Fts5Context*);
+  int (*xPhraseSize)(Fts5Context*, int iPhrase);
+
+  int (*xInstCount)(Fts5Context*, int *pnInst);
+  int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
+
+  sqlite3_int64 (*xRowid)(Fts5Context*);
+  int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
+
+  int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
+    int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
+  );
+  int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
+  void *(*xGetAuxdata)(Fts5Context*, int bClear);
+
+  int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
+  void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
+
+  int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
+  void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
+
+  /* Below this point are iVersion>=3 only */
+  int (*xQueryToken)(Fts5Context*,
+      int iPhrase, int iToken,
+      const char **ppToken, int *pnToken
+  );
+  int (*xInstToken)(Fts5Context*, int iIdx, int iToken, const char**, int*);
+
+  /* Below this point are iVersion>=4 only */
+  int (*xColumnLocale)(Fts5Context*, int iCol, const char **pz, int *pn);
+  int (*xTokenize_v2)(Fts5Context*,
+    const char *pText, int nText,      /* Text to tokenize */
+    const char *pLocale, int nLocale,  /* Locale to pass to tokenizer */
+    void *pCtx,                        /* Context passed to xToken() */
+    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
+  );
+};
+
+/*
+** CUSTOM AUXILIARY FUNCTIONS
+*************************************************************************/
+
+/*************************************************************************
+** CUSTOM TOKENIZERS
+**
+** Applications may also register custom tokenizer types. A tokenizer
+** is registered by providing fts5 with a populated instance of the
+** following structure. All structure methods must be defined, setting
+** any member of the fts5_tokenizer struct to NULL leads to undefined
+** behaviour. The structure methods are expected to function as follows:
+**
+** xCreate:
+**   This function is used to allocate and initialize a tokenizer instance.
+**   A tokenizer instance is required to actually tokenize text.
+**
+**   The first argument passed to this function is a copy of the (void*)
+**   pointer provided by the application when the fts5_tokenizer_v2 object
+**   was registered with FTS5 (the third argument to xCreateTokenizer()).
+**   The second and third arguments are an array of nul-terminated strings
+**   containing the tokenizer arguments, if any, specified following the
+**   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
+**   to create the FTS5 table.
+**
+**   The final argument is an output variable. If successful, (*ppOut)
+**   should be set to point to the new tokenizer handle and SQLITE_OK
+**   returned. If an error occurs, some value other than SQLITE_OK should
+**   be returned. In this case, fts5 assumes that the final value of *ppOut
+**   is undefined.
+**
+** xDelete:
+**   This function is invoked to delete a tokenizer handle previously
+**   allocated using xCreate(). Fts5 guarantees that this function will
+**   be invoked exactly once for each successful call to xCreate().
+**
+** xTokenize:
+**   This function is expected to tokenize the nText byte string indicated
+**   by argument pText. pText may or may not be nul-terminated. The first
+**   argument passed to this function is a pointer to an Fts5Tokenizer object
+**   returned by an earlier call to xCreate().
+**
+**   The third argument indicates the reason that FTS5 is requesting
+**   tokenization of the supplied text. This is always one of the following
+**   four values:
+**
+**   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
+**            or removed from the FTS table. The tokenizer is being invoked to
+**            determine the set of tokens to add to (or delete from) the
+**            FTS index.
+**
+**       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
+**            against the FTS index. The tokenizer is being called to tokenize
+**            a bareword or quoted string specified as part of the query.
+**
+**       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
+**            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
+**            followed by a "*" character, indicating that the last token
+**            returned by the tokenizer will be treated as a token prefix.
+**
+**       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
+**            satisfy an fts5_api.xTokenize() request made by an auxiliary
+**            function. Or an fts5_api.xColumnSize() request made by the same
+**            on a columnsize=0 database.
+**   </ul>
+**
+**   The sixth and seventh arguments passed to xTokenize() - pLocale and
+**   nLocale - are a pointer to a buffer containing the locale to use for
+**   tokenization (e.g. "en_US") and its size in bytes, respectively. The
+**   pLocale buffer is not nul-terminated. pLocale may be passed NULL (in
+**   which case nLocale is always 0) to indicate that the tokenizer should
+**   use its default locale.
+**
+**   For each token in the input string, the supplied callback xToken() must
+**   be invoked. The first argument to it should be a copy of the pointer
+**   passed as the second argument to xTokenize(). The third and fourth
+**   arguments are a pointer to a buffer containing the token text, and the
+**   size of the token in bytes. The 4th and 5th arguments are the byte offsets
+**   of the first byte of and first byte immediately following the text from
+**   which the token is derived within the input.
+**
+**   The second argument passed to the xToken() callback ("tflags") should
+**   normally be set to 0. The exception is if the tokenizer supports
+**   synonyms. In this case see the discussion below for details.
+**
+**   FTS5 assumes the xToken() callback is invoked for each token in the
+**   order that they occur within the input text.
+**
+**   If an xToken() callback returns any value other than SQLITE_OK, then
+**   the tokenization should be abandoned and the xTokenize() method should
+**   immediately return a copy of the xToken() return value. Or, if the
+**   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
+**   if an error occurs with the xTokenize() implementation itself, it
+**   may abandon the tokenization and return any error code other than
+**   SQLITE_OK or SQLITE_DONE.
+**
+**   If the tokenizer is registered using an fts5_tokenizer_v2 object,
+**   then the xTokenize() method has two additional arguments - pLocale
+**   and nLocale. These specify the locale that the tokenizer should use
+**   for the current request. If pLocale and nLocale are both 0, then the
+**   tokenizer should use its default locale. Otherwise, pLocale points to
+**   an nLocale byte buffer containing the name of the locale to use as utf-8
+**   text. pLocale is not nul-terminated.
+**
+** FTS5_TOKENIZER
+**
+** There is also an fts5_tokenizer object. This is an older, deprecated,
+** version of fts5_tokenizer_v2. It is similar except that:
+**
+**  <ul>
+**    <li> There is no "iVersion" field, and
+**    <li> The xTokenize() method does not take a locale argument.
+**  </ul>
+**
+** Legacy fts5_tokenizer tokenizers must be registered using the
+** legacy xCreateTokenizer() function, instead of xCreateTokenizer_v2().
+**
+** Tokenizer implementations registered using either API may be retrieved
+** using both xFindTokenizer() and xFindTokenizer_v2().
+**
+** SYNONYM SUPPORT
+**
+**   Custom tokenizers may also support synonyms. Consider a case in which a
+**   user wishes to query for a phrase such as "first place". Using the
+**   built-in tokenizers, the FTS5 query 'first + place' will match instances
+**   of "first place" within the document set, but not alternative forms
+**   such as "1st place". In some applications, it would be better to match
+**   all instances of "first place" or "1st place" regardless of which form
+**   the user specified in the MATCH query text.
+**
+**   There are several ways to approach this in FTS5:
+**
+**   <ol><li> By mapping all synonyms to a single token. In this case, using
+**            the above example, this means that the tokenizer returns the
+**            same token for inputs "first" and "1st". Say that token is in
+**            fact "first", so that when the user inserts the document "I won
+**            1st place" entries are added to the index for tokens "i", "won",
+**            "first" and "place". If the user then queries for '1st + place',
+**            the tokenizer substitutes "first" for "1st" and the query works
+**            as expected.
+**
+**       <li> By querying the index for all synonyms of each query term
+**            separately. In this case, when tokenizing query text, the
+**            tokenizer may provide multiple synonyms for a single term
+**            within the document. FTS5 then queries the index for each
+**            synonym individually. For example, faced with the query:
+**
+**   <codeblock>
+**     ... MATCH 'first place'</codeblock>
+**
+**            the tokenizer offers both "1st" and "first" as synonyms for the
+**            first token in the MATCH query and FTS5 effectively runs a query
+**            similar to:
+**
+**   <codeblock>
+**     ... MATCH '(first OR 1st) place'</codeblock>
+**
+**            except that, for the purposes of auxiliary functions, the query
+**            still appears to contain just two phrases - "(first OR 1st)"
+**            being treated as a single phrase.
+**
+**       <li> By adding multiple synonyms for a single term to the FTS index.
+**            Using this method, when tokenizing document text, the tokenizer
+**            provides multiple synonyms for each token. So that when a
+**            document such as "I won first place" is tokenized, entries are
+**            added to the FTS index for "i", "won", "first", "1st" and
+**            "place".
+**
+**            This way, even if the tokenizer does not provide synonyms
+**            when tokenizing query text (it should not - to do so would be
+**            inefficient), it doesn't matter if the user queries for
+**            'first + place' or '1st + place', as there are entries in the
+**            FTS index corresponding to both forms of the first token.
+**   </ol>
+**
+**   Whether it is parsing document or query text, any call to xToken that
+**   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
+**   is considered to supply a synonym for the previous token. For example,
+**   when parsing the document "I won first place", a tokenizer that supports
+**   synonyms would call xToken() 5 times, as follows:
+**
+**   <codeblock>
+**       xToken(pCtx, 0, "i",                      1,  0,  1);
+**       xToken(pCtx, 0, "won",                    3,  2,  5);
+**       xToken(pCtx, 0, "first",                  5,  6, 11);
+**       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
+**       xToken(pCtx, 0, "place",                  5, 12, 17);
+**</codeblock>
+**
+**   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
+**   xToken() is called. Multiple synonyms may be specified for a single token
+**   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
+**   There is no limit to the number of synonyms that may be provided for a
+**   single token.
+**
+**   In many cases, method (1) above is the best approach. It does not add
+**   extra data to the FTS index or require FTS5 to query for multiple terms,
+**   so it is efficient in terms of disk space and query speed. However, it
+**   does not support prefix queries very well. If, as suggested above, the
+**   token "first" is substituted for "1st" by the tokenizer, then the query:
+**
+**   <codeblock>
+**     ... MATCH '1s*'</codeblock>
+**
+**   will not match documents that contain the token "1st" (as the tokenizer
+**   will probably not map "1s" to any prefix of "first").
+**
+**   For full prefix support, method (3) may be preferred. In this case,
+**   because the index contains entries for both "first" and "1st", prefix
+**   queries such as 'fi*' or '1s*' will match correctly. However, because
+**   extra entries are added to the FTS index, this method uses more space
+**   within the database.
+**
+**   Method (2) offers a midpoint between (1) and (3). Using this method,
+**   a query such as '1s*' will match documents that contain the literal
+**   token "1st", but not "first" (assuming the tokenizer is not able to
+**   provide synonyms for prefixes). However, a non-prefix query like '1st'
+**   will match against "1st" and "first". This method does not require
+**   extra disk space, as no extra entries are added to the FTS index.
+**   On the other hand, it may require more CPU cycles to run MATCH queries,
+**   as separate queries of the FTS index are required for each synonym.
+**
+**   When using methods (2) or (3), it is important that the tokenizer only
+**   provide synonyms when tokenizing document text (method (3)) or query
+**   text (method (2)), not both. Doing so will not cause any errors, but is
+**   inefficient.
+*/
+typedef struct Fts5Tokenizer Fts5Tokenizer;
+typedef struct fts5_tokenizer_v2 fts5_tokenizer_v2;
+struct fts5_tokenizer_v2 {
+  int iVersion;             /* Currently always 2 */
+
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      const char *pLocale, int nLocale,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+/*
+** New code should use the fts5_tokenizer_v2 type to define tokenizer
+** implementations. The following type is included for legacy applications
+** that still use it.
+*/
+typedef struct fts5_tokenizer fts5_tokenizer;
+struct fts5_tokenizer {
+  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
+  void (*xDelete)(Fts5Tokenizer*);
+  int (*xTokenize)(Fts5Tokenizer*,
+      void *pCtx,
+      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
+      const char *pText, int nText,
+      int (*xToken)(
+        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
+        int tflags,         /* Mask of FTS5_TOKEN_* flags */
+        const char *pToken, /* Pointer to buffer containing token */
+        int nToken,         /* Size of token in bytes */
+        int iStart,         /* Byte offset of token within input text */
+        int iEnd            /* Byte offset of end of token within input text */
+      )
+  );
+};
+
+
+/* Flags that may be passed as the third argument to xTokenize() */
+#define FTS5_TOKENIZE_QUERY     0x0001
+#define FTS5_TOKENIZE_PREFIX    0x0002
+#define FTS5_TOKENIZE_DOCUMENT  0x0004
+#define FTS5_TOKENIZE_AUX       0x0008
+
+/* Flags that may be passed by the tokenizer implementation back to FTS5
+** as the third argument to the supplied xToken callback. */
+#define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
+
+/*
+** END OF CUSTOM TOKENIZERS
+*************************************************************************/
+
+/*************************************************************************
+** FTS5 EXTENSION REGISTRATION API
+*/
+typedef struct fts5_api fts5_api;
+struct fts5_api {
+  int iVersion;                   /* Currently always set to 3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer *pTokenizer
+  );
+
+  /* Create a new auxiliary function */
+  int (*xCreateFunction)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_extension_function xFunction,
+    void (*xDestroy)(void*)
+  );
+
+  /* APIs below this point are only available if iVersion>=3 */
+
+  /* Create a new tokenizer */
+  int (*xCreateTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void *pUserData,
+    fts5_tokenizer_v2 *pTokenizer,
+    void (*xDestroy)(void*)
+  );
+
+  /* Find an existing tokenizer */
+  int (*xFindTokenizer_v2)(
+    fts5_api *pApi,
+    const char *zName,
+    void **ppUserData,
+    fts5_tokenizer_v2 **ppTokenizer
+  );
+};
+
+/*
+** END OF REGISTRATION API
+*************************************************************************/
+
+#ifdef __cplusplus
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* _FTS5_H */
+
+/******** End of fts5.h *********/
+#endif /* SQLITE3_H */
diff --git a/server/node_modules/better-sqlite3/deps/sqlite3/sqlite3ext.h b/server/node_modules/better-sqlite3/deps/sqlite3/sqlite3ext.h
new file mode 100644
index 0000000..ae0949b
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/sqlite3/sqlite3ext.h
@@ -0,0 +1,719 @@
+/*
+** 2006 June 7
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This header file defines the SQLite interface for use by
+** shared libraries that want to be imported as extensions into
+** an SQLite instance.  Shared libraries that intend to be loaded
+** as extensions by SQLite should #include this file instead of 
+** sqlite3.h.
+*/
+#ifndef SQLITE3EXT_H
+#define SQLITE3EXT_H
+#include "sqlite3.h"
+
+/*
+** The following structure holds pointers to all of the SQLite API
+** routines.
+**
+** WARNING:  In order to maintain backwards compatibility, add new
+** interfaces to the end of this structure only.  If you insert new
+** interfaces in the middle of this structure, then older different
+** versions of SQLite will not be able to load each other's shared
+** libraries!
+*/
+struct sqlite3_api_routines {
+  void * (*aggregate_context)(sqlite3_context*,int nBytes);
+  int  (*aggregate_count)(sqlite3_context*);
+  int  (*bind_blob)(sqlite3_stmt*,int,const void*,int n,void(*)(void*));
+  int  (*bind_double)(sqlite3_stmt*,int,double);
+  int  (*bind_int)(sqlite3_stmt*,int,int);
+  int  (*bind_int64)(sqlite3_stmt*,int,sqlite_int64);
+  int  (*bind_null)(sqlite3_stmt*,int);
+  int  (*bind_parameter_count)(sqlite3_stmt*);
+  int  (*bind_parameter_index)(sqlite3_stmt*,const char*zName);
+  const char * (*bind_parameter_name)(sqlite3_stmt*,int);
+  int  (*bind_text)(sqlite3_stmt*,int,const char*,int n,void(*)(void*));
+  int  (*bind_text16)(sqlite3_stmt*,int,const void*,int,void(*)(void*));
+  int  (*bind_value)(sqlite3_stmt*,int,const sqlite3_value*);
+  int  (*busy_handler)(sqlite3*,int(*)(void*,int),void*);
+  int  (*busy_timeout)(sqlite3*,int ms);
+  int  (*changes)(sqlite3*);
+  int  (*close)(sqlite3*);
+  int  (*collation_needed)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                           int eTextRep,const char*));
+  int  (*collation_needed16)(sqlite3*,void*,void(*)(void*,sqlite3*,
+                             int eTextRep,const void*));
+  const void * (*column_blob)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes)(sqlite3_stmt*,int iCol);
+  int  (*column_bytes16)(sqlite3_stmt*,int iCol);
+  int  (*column_count)(sqlite3_stmt*pStmt);
+  const char * (*column_database_name)(sqlite3_stmt*,int);
+  const void * (*column_database_name16)(sqlite3_stmt*,int);
+  const char * (*column_decltype)(sqlite3_stmt*,int i);
+  const void * (*column_decltype16)(sqlite3_stmt*,int);
+  double  (*column_double)(sqlite3_stmt*,int iCol);
+  int  (*column_int)(sqlite3_stmt*,int iCol);
+  sqlite_int64  (*column_int64)(sqlite3_stmt*,int iCol);
+  const char * (*column_name)(sqlite3_stmt*,int);
+  const void * (*column_name16)(sqlite3_stmt*,int);
+  const char * (*column_origin_name)(sqlite3_stmt*,int);
+  const void * (*column_origin_name16)(sqlite3_stmt*,int);
+  const char * (*column_table_name)(sqlite3_stmt*,int);
+  const void * (*column_table_name16)(sqlite3_stmt*,int);
+  const unsigned char * (*column_text)(sqlite3_stmt*,int iCol);
+  const void * (*column_text16)(sqlite3_stmt*,int iCol);
+  int  (*column_type)(sqlite3_stmt*,int iCol);
+  sqlite3_value* (*column_value)(sqlite3_stmt*,int iCol);
+  void * (*commit_hook)(sqlite3*,int(*)(void*),void*);
+  int  (*complete)(const char*sql);
+  int  (*complete16)(const void*sql);
+  int  (*create_collation)(sqlite3*,const char*,int,void*,
+                           int(*)(void*,int,const void*,int,const void*));
+  int  (*create_collation16)(sqlite3*,const void*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*));
+  int  (*create_function)(sqlite3*,const char*,int,int,void*,
+                          void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                          void (*xFinal)(sqlite3_context*));
+  int  (*create_function16)(sqlite3*,const void*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*));
+  int (*create_module)(sqlite3*,const char*,const sqlite3_module*,void*);
+  int  (*data_count)(sqlite3_stmt*pStmt);
+  sqlite3 * (*db_handle)(sqlite3_stmt*);
+  int (*declare_vtab)(sqlite3*,const char*);
+  int  (*enable_shared_cache)(int);
+  int  (*errcode)(sqlite3*db);
+  const char * (*errmsg)(sqlite3*);
+  const void * (*errmsg16)(sqlite3*);
+  int  (*exec)(sqlite3*,const char*,sqlite3_callback,void*,char**);
+  int  (*expired)(sqlite3_stmt*);
+  int  (*finalize)(sqlite3_stmt*pStmt);
+  void  (*free)(void*);
+  void  (*free_table)(char**result);
+  int  (*get_autocommit)(sqlite3*);
+  void * (*get_auxdata)(sqlite3_context*,int);
+  int  (*get_table)(sqlite3*,const char*,char***,int*,int*,char**);
+  int  (*global_recover)(void);
+  void  (*interruptx)(sqlite3*);
+  sqlite_int64  (*last_insert_rowid)(sqlite3*);
+  const char * (*libversion)(void);
+  int  (*libversion_number)(void);
+  void *(*malloc)(int);
+  char * (*mprintf)(const char*,...);
+  int  (*open)(const char*,sqlite3**);
+  int  (*open16)(const void*,sqlite3**);
+  int  (*prepare)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int  (*prepare16)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  void * (*profile)(sqlite3*,void(*)(void*,const char*,sqlite_uint64),void*);
+  void  (*progress_handler)(sqlite3*,int,int(*)(void*),void*);
+  void *(*realloc)(void*,int);
+  int  (*reset)(sqlite3_stmt*pStmt);
+  void  (*result_blob)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_double)(sqlite3_context*,double);
+  void  (*result_error)(sqlite3_context*,const char*,int);
+  void  (*result_error16)(sqlite3_context*,const void*,int);
+  void  (*result_int)(sqlite3_context*,int);
+  void  (*result_int64)(sqlite3_context*,sqlite_int64);
+  void  (*result_null)(sqlite3_context*);
+  void  (*result_text)(sqlite3_context*,const char*,int,void(*)(void*));
+  void  (*result_text16)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16be)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_text16le)(sqlite3_context*,const void*,int,void(*)(void*));
+  void  (*result_value)(sqlite3_context*,sqlite3_value*);
+  void * (*rollback_hook)(sqlite3*,void(*)(void*),void*);
+  int  (*set_authorizer)(sqlite3*,int(*)(void*,int,const char*,const char*,
+                         const char*,const char*),void*);
+  void  (*set_auxdata)(sqlite3_context*,int,void*,void (*)(void*));
+  char * (*xsnprintf)(int,char*,const char*,...);
+  int  (*step)(sqlite3_stmt*);
+  int  (*table_column_metadata)(sqlite3*,const char*,const char*,const char*,
+                                char const**,char const**,int*,int*,int*);
+  void  (*thread_cleanup)(void);
+  int  (*total_changes)(sqlite3*);
+  void * (*trace)(sqlite3*,void(*xTrace)(void*,const char*),void*);
+  int  (*transfer_bindings)(sqlite3_stmt*,sqlite3_stmt*);
+  void * (*update_hook)(sqlite3*,void(*)(void*,int ,char const*,char const*,
+                                         sqlite_int64),void*);
+  void * (*user_data)(sqlite3_context*);
+  const void * (*value_blob)(sqlite3_value*);
+  int  (*value_bytes)(sqlite3_value*);
+  int  (*value_bytes16)(sqlite3_value*);
+  double  (*value_double)(sqlite3_value*);
+  int  (*value_int)(sqlite3_value*);
+  sqlite_int64  (*value_int64)(sqlite3_value*);
+  int  (*value_numeric_type)(sqlite3_value*);
+  const unsigned char * (*value_text)(sqlite3_value*);
+  const void * (*value_text16)(sqlite3_value*);
+  const void * (*value_text16be)(sqlite3_value*);
+  const void * (*value_text16le)(sqlite3_value*);
+  int  (*value_type)(sqlite3_value*);
+  char *(*vmprintf)(const char*,va_list);
+  /* Added ??? */
+  int (*overload_function)(sqlite3*, const char *zFuncName, int nArg);
+  /* Added by 3.3.13 */
+  int (*prepare_v2)(sqlite3*,const char*,int,sqlite3_stmt**,const char**);
+  int (*prepare16_v2)(sqlite3*,const void*,int,sqlite3_stmt**,const void**);
+  int (*clear_bindings)(sqlite3_stmt*);
+  /* Added by 3.4.1 */
+  int (*create_module_v2)(sqlite3*,const char*,const sqlite3_module*,void*,
+                          void (*xDestroy)(void *));
+  /* Added by 3.5.0 */
+  int (*bind_zeroblob)(sqlite3_stmt*,int,int);
+  int (*blob_bytes)(sqlite3_blob*);
+  int (*blob_close)(sqlite3_blob*);
+  int (*blob_open)(sqlite3*,const char*,const char*,const char*,sqlite3_int64,
+                   int,sqlite3_blob**);
+  int (*blob_read)(sqlite3_blob*,void*,int,int);
+  int (*blob_write)(sqlite3_blob*,const void*,int,int);
+  int (*create_collation_v2)(sqlite3*,const char*,int,void*,
+                             int(*)(void*,int,const void*,int,const void*),
+                             void(*)(void*));
+  int (*file_control)(sqlite3*,const char*,int,void*);
+  sqlite3_int64 (*memory_highwater)(int);
+  sqlite3_int64 (*memory_used)(void);
+  sqlite3_mutex *(*mutex_alloc)(int);
+  void (*mutex_enter)(sqlite3_mutex*);
+  void (*mutex_free)(sqlite3_mutex*);
+  void (*mutex_leave)(sqlite3_mutex*);
+  int (*mutex_try)(sqlite3_mutex*);
+  int (*open_v2)(const char*,sqlite3**,int,const char*);
+  int (*release_memory)(int);
+  void (*result_error_nomem)(sqlite3_context*);
+  void (*result_error_toobig)(sqlite3_context*);
+  int (*sleep)(int);
+  void (*soft_heap_limit)(int);
+  sqlite3_vfs *(*vfs_find)(const char*);
+  int (*vfs_register)(sqlite3_vfs*,int);
+  int (*vfs_unregister)(sqlite3_vfs*);
+  int (*xthreadsafe)(void);
+  void (*result_zeroblob)(sqlite3_context*,int);
+  void (*result_error_code)(sqlite3_context*,int);
+  int (*test_control)(int, ...);
+  void (*randomness)(int,void*);
+  sqlite3 *(*context_db_handle)(sqlite3_context*);
+  int (*extended_result_codes)(sqlite3*,int);
+  int (*limit)(sqlite3*,int,int);
+  sqlite3_stmt *(*next_stmt)(sqlite3*,sqlite3_stmt*);
+  const char *(*sql)(sqlite3_stmt*);
+  int (*status)(int,int*,int*,int);
+  int (*backup_finish)(sqlite3_backup*);
+  sqlite3_backup *(*backup_init)(sqlite3*,const char*,sqlite3*,const char*);
+  int (*backup_pagecount)(sqlite3_backup*);
+  int (*backup_remaining)(sqlite3_backup*);
+  int (*backup_step)(sqlite3_backup*,int);
+  const char *(*compileoption_get)(int);
+  int (*compileoption_used)(const char*);
+  int (*create_function_v2)(sqlite3*,const char*,int,int,void*,
+                            void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void(*xDestroy)(void*));
+  int (*db_config)(sqlite3*,int,...);
+  sqlite3_mutex *(*db_mutex)(sqlite3*);
+  int (*db_status)(sqlite3*,int,int*,int*,int);
+  int (*extended_errcode)(sqlite3*);
+  void (*log)(int,const char*,...);
+  sqlite3_int64 (*soft_heap_limit64)(sqlite3_int64);
+  const char *(*sourceid)(void);
+  int (*stmt_status)(sqlite3_stmt*,int,int);
+  int (*strnicmp)(const char*,const char*,int);
+  int (*unlock_notify)(sqlite3*,void(*)(void**,int),void*);
+  int (*wal_autocheckpoint)(sqlite3*,int);
+  int (*wal_checkpoint)(sqlite3*,const char*);
+  void *(*wal_hook)(sqlite3*,int(*)(void*,sqlite3*,const char*,int),void*);
+  int (*blob_reopen)(sqlite3_blob*,sqlite3_int64);
+  int (*vtab_config)(sqlite3*,int op,...);
+  int (*vtab_on_conflict)(sqlite3*);
+  /* Version 3.7.16 and later */
+  int (*close_v2)(sqlite3*);
+  const char *(*db_filename)(sqlite3*,const char*);
+  int (*db_readonly)(sqlite3*,const char*);
+  int (*db_release_memory)(sqlite3*);
+  const char *(*errstr)(int);
+  int (*stmt_busy)(sqlite3_stmt*);
+  int (*stmt_readonly)(sqlite3_stmt*);
+  int (*stricmp)(const char*,const char*);
+  int (*uri_boolean)(const char*,const char*,int);
+  sqlite3_int64 (*uri_int64)(const char*,const char*,sqlite3_int64);
+  const char *(*uri_parameter)(const char*,const char*);
+  char *(*xvsnprintf)(int,char*,const char*,va_list);
+  int (*wal_checkpoint_v2)(sqlite3*,const char*,int,int*,int*);
+  /* Version 3.8.7 and later */
+  int (*auto_extension)(void(*)(void));
+  int (*bind_blob64)(sqlite3_stmt*,int,const void*,sqlite3_uint64,
+                     void(*)(void*));
+  int (*bind_text64)(sqlite3_stmt*,int,const char*,sqlite3_uint64,
+                      void(*)(void*),unsigned char);
+  int (*cancel_auto_extension)(void(*)(void));
+  int (*load_extension)(sqlite3*,const char*,const char*,char**);
+  void *(*malloc64)(sqlite3_uint64);
+  sqlite3_uint64 (*msize)(void*);
+  void *(*realloc64)(void*,sqlite3_uint64);
+  void (*reset_auto_extension)(void);
+  void (*result_blob64)(sqlite3_context*,const void*,sqlite3_uint64,
+                        void(*)(void*));
+  void (*result_text64)(sqlite3_context*,const char*,sqlite3_uint64,
+                         void(*)(void*), unsigned char);
+  int (*strglob)(const char*,const char*);
+  /* Version 3.8.11 and later */
+  sqlite3_value *(*value_dup)(const sqlite3_value*);
+  void (*value_free)(sqlite3_value*);
+  int (*result_zeroblob64)(sqlite3_context*,sqlite3_uint64);
+  int (*bind_zeroblob64)(sqlite3_stmt*, int, sqlite3_uint64);
+  /* Version 3.9.0 and later */
+  unsigned int (*value_subtype)(sqlite3_value*);
+  void (*result_subtype)(sqlite3_context*,unsigned int);
+  /* Version 3.10.0 and later */
+  int (*status64)(int,sqlite3_int64*,sqlite3_int64*,int);
+  int (*strlike)(const char*,const char*,unsigned int);
+  int (*db_cacheflush)(sqlite3*);
+  /* Version 3.12.0 and later */
+  int (*system_errno)(sqlite3*);
+  /* Version 3.14.0 and later */
+  int (*trace_v2)(sqlite3*,unsigned,int(*)(unsigned,void*,void*,void*),void*);
+  char *(*expanded_sql)(sqlite3_stmt*);
+  /* Version 3.18.0 and later */
+  void (*set_last_insert_rowid)(sqlite3*,sqlite3_int64);
+  /* Version 3.20.0 and later */
+  int (*prepare_v3)(sqlite3*,const char*,int,unsigned int,
+                    sqlite3_stmt**,const char**);
+  int (*prepare16_v3)(sqlite3*,const void*,int,unsigned int,
+                      sqlite3_stmt**,const void**);
+  int (*bind_pointer)(sqlite3_stmt*,int,void*,const char*,void(*)(void*));
+  void (*result_pointer)(sqlite3_context*,void*,const char*,void(*)(void*));
+  void *(*value_pointer)(sqlite3_value*,const char*);
+  int (*vtab_nochange)(sqlite3_context*);
+  int (*value_nochange)(sqlite3_value*);
+  const char *(*vtab_collation)(sqlite3_index_info*,int);
+  /* Version 3.24.0 and later */
+  int (*keyword_count)(void);
+  int (*keyword_name)(int,const char**,int*);
+  int (*keyword_check)(const char*,int);
+  sqlite3_str *(*str_new)(sqlite3*);
+  char *(*str_finish)(sqlite3_str*);
+  void (*str_appendf)(sqlite3_str*, const char *zFormat, ...);
+  void (*str_vappendf)(sqlite3_str*, const char *zFormat, va_list);
+  void (*str_append)(sqlite3_str*, const char *zIn, int N);
+  void (*str_appendall)(sqlite3_str*, const char *zIn);
+  void (*str_appendchar)(sqlite3_str*, int N, char C);
+  void (*str_reset)(sqlite3_str*);
+  int (*str_errcode)(sqlite3_str*);
+  int (*str_length)(sqlite3_str*);
+  char *(*str_value)(sqlite3_str*);
+  /* Version 3.25.0 and later */
+  int (*create_window_function)(sqlite3*,const char*,int,int,void*,
+                            void (*xStep)(sqlite3_context*,int,sqlite3_value**),
+                            void (*xFinal)(sqlite3_context*),
+                            void (*xValue)(sqlite3_context*),
+                            void (*xInv)(sqlite3_context*,int,sqlite3_value**),
+                            void(*xDestroy)(void*));
+  /* Version 3.26.0 and later */
+  const char *(*normalized_sql)(sqlite3_stmt*);
+  /* Version 3.28.0 and later */
+  int (*stmt_isexplain)(sqlite3_stmt*);
+  int (*value_frombind)(sqlite3_value*);
+  /* Version 3.30.0 and later */
+  int (*drop_modules)(sqlite3*,const char**);
+  /* Version 3.31.0 and later */
+  sqlite3_int64 (*hard_heap_limit64)(sqlite3_int64);
+  const char *(*uri_key)(const char*,int);
+  const char *(*filename_database)(const char*);
+  const char *(*filename_journal)(const char*);
+  const char *(*filename_wal)(const char*);
+  /* Version 3.32.0 and later */
+  const char *(*create_filename)(const char*,const char*,const char*,
+                           int,const char**);
+  void (*free_filename)(const char*);
+  sqlite3_file *(*database_file_object)(const char*);
+  /* Version 3.34.0 and later */
+  int (*txn_state)(sqlite3*,const char*);
+  /* Version 3.36.1 and later */
+  sqlite3_int64 (*changes64)(sqlite3*);
+  sqlite3_int64 (*total_changes64)(sqlite3*);
+  /* Version 3.37.0 and later */
+  int (*autovacuum_pages)(sqlite3*,
+     unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
+     void*, void(*)(void*));
+  /* Version 3.38.0 and later */
+  int (*error_offset)(sqlite3*);
+  int (*vtab_rhs_value)(sqlite3_index_info*,int,sqlite3_value**);
+  int (*vtab_distinct)(sqlite3_index_info*);
+  int (*vtab_in)(sqlite3_index_info*,int,int);
+  int (*vtab_in_first)(sqlite3_value*,sqlite3_value**);
+  int (*vtab_in_next)(sqlite3_value*,sqlite3_value**);
+  /* Version 3.39.0 and later */
+  int (*deserialize)(sqlite3*,const char*,unsigned char*,
+                     sqlite3_int64,sqlite3_int64,unsigned);
+  unsigned char *(*serialize)(sqlite3*,const char *,sqlite3_int64*,
+                              unsigned int);
+  const char *(*db_name)(sqlite3*,int);
+  /* Version 3.40.0 and later */
+  int (*value_encoding)(sqlite3_value*);
+  /* Version 3.41.0 and later */
+  int (*is_interrupted)(sqlite3*);
+  /* Version 3.43.0 and later */
+  int (*stmt_explain)(sqlite3_stmt*,int);
+  /* Version 3.44.0 and later */
+  void *(*get_clientdata)(sqlite3*,const char*);
+  int (*set_clientdata)(sqlite3*, const char*, void*, void(*)(void*));
+};
+
+/*
+** This is the function signature used for all extension entry points.  It
+** is also defined in the file "loadext.c".
+*/
+typedef int (*sqlite3_loadext_entry)(
+  sqlite3 *db,                       /* Handle to the database. */
+  char **pzErrMsg,                   /* Used to set error string on failure. */
+  const sqlite3_api_routines *pThunk /* Extension API function pointers. */
+);
+
+/*
+** The following macros redefine the API routines so that they are
+** redirected through the global sqlite3_api structure.
+**
+** This header file is also used by the loadext.c source file
+** (part of the main SQLite library - not an extension) so that
+** it can get access to the sqlite3_api_routines structure
+** definition.  But the main library does not want to redefine
+** the API.  So the redefinition macros are only valid if the
+** SQLITE_CORE macros is undefined.
+*/
+#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+#define sqlite3_aggregate_context      sqlite3_api->aggregate_context
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_aggregate_count        sqlite3_api->aggregate_count
+#endif
+#define sqlite3_bind_blob              sqlite3_api->bind_blob
+#define sqlite3_bind_double            sqlite3_api->bind_double
+#define sqlite3_bind_int               sqlite3_api->bind_int
+#define sqlite3_bind_int64             sqlite3_api->bind_int64
+#define sqlite3_bind_null              sqlite3_api->bind_null
+#define sqlite3_bind_parameter_count   sqlite3_api->bind_parameter_count
+#define sqlite3_bind_parameter_index   sqlite3_api->bind_parameter_index
+#define sqlite3_bind_parameter_name    sqlite3_api->bind_parameter_name
+#define sqlite3_bind_text              sqlite3_api->bind_text
+#define sqlite3_bind_text16            sqlite3_api->bind_text16
+#define sqlite3_bind_value             sqlite3_api->bind_value
+#define sqlite3_busy_handler           sqlite3_api->busy_handler
+#define sqlite3_busy_timeout           sqlite3_api->busy_timeout
+#define sqlite3_changes                sqlite3_api->changes
+#define sqlite3_close                  sqlite3_api->close
+#define sqlite3_collation_needed       sqlite3_api->collation_needed
+#define sqlite3_collation_needed16     sqlite3_api->collation_needed16
+#define sqlite3_column_blob            sqlite3_api->column_blob
+#define sqlite3_column_bytes           sqlite3_api->column_bytes
+#define sqlite3_column_bytes16         sqlite3_api->column_bytes16
+#define sqlite3_column_count           sqlite3_api->column_count
+#define sqlite3_column_database_name   sqlite3_api->column_database_name
+#define sqlite3_column_database_name16 sqlite3_api->column_database_name16
+#define sqlite3_column_decltype        sqlite3_api->column_decltype
+#define sqlite3_column_decltype16      sqlite3_api->column_decltype16
+#define sqlite3_column_double          sqlite3_api->column_double
+#define sqlite3_column_int             sqlite3_api->column_int
+#define sqlite3_column_int64           sqlite3_api->column_int64
+#define sqlite3_column_name            sqlite3_api->column_name
+#define sqlite3_column_name16          sqlite3_api->column_name16
+#define sqlite3_column_origin_name     sqlite3_api->column_origin_name
+#define sqlite3_column_origin_name16   sqlite3_api->column_origin_name16
+#define sqlite3_column_table_name      sqlite3_api->column_table_name
+#define sqlite3_column_table_name16    sqlite3_api->column_table_name16
+#define sqlite3_column_text            sqlite3_api->column_text
+#define sqlite3_column_text16          sqlite3_api->column_text16
+#define sqlite3_column_type            sqlite3_api->column_type
+#define sqlite3_column_value           sqlite3_api->column_value
+#define sqlite3_commit_hook            sqlite3_api->commit_hook
+#define sqlite3_complete               sqlite3_api->complete
+#define sqlite3_complete16             sqlite3_api->complete16
+#define sqlite3_create_collation       sqlite3_api->create_collation
+#define sqlite3_create_collation16     sqlite3_api->create_collation16
+#define sqlite3_create_function        sqlite3_api->create_function
+#define sqlite3_create_function16      sqlite3_api->create_function16
+#define sqlite3_create_module          sqlite3_api->create_module
+#define sqlite3_create_module_v2       sqlite3_api->create_module_v2
+#define sqlite3_data_count             sqlite3_api->data_count
+#define sqlite3_db_handle              sqlite3_api->db_handle
+#define sqlite3_declare_vtab           sqlite3_api->declare_vtab
+#define sqlite3_enable_shared_cache    sqlite3_api->enable_shared_cache
+#define sqlite3_errcode                sqlite3_api->errcode
+#define sqlite3_errmsg                 sqlite3_api->errmsg
+#define sqlite3_errmsg16               sqlite3_api->errmsg16
+#define sqlite3_exec                   sqlite3_api->exec
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_expired                sqlite3_api->expired
+#endif
+#define sqlite3_finalize               sqlite3_api->finalize
+#define sqlite3_free                   sqlite3_api->free
+#define sqlite3_free_table             sqlite3_api->free_table
+#define sqlite3_get_autocommit         sqlite3_api->get_autocommit
+#define sqlite3_get_auxdata            sqlite3_api->get_auxdata
+#define sqlite3_get_table              sqlite3_api->get_table
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_global_recover         sqlite3_api->global_recover
+#endif
+#define sqlite3_interrupt              sqlite3_api->interruptx
+#define sqlite3_last_insert_rowid      sqlite3_api->last_insert_rowid
+#define sqlite3_libversion             sqlite3_api->libversion
+#define sqlite3_libversion_number      sqlite3_api->libversion_number
+#define sqlite3_malloc                 sqlite3_api->malloc
+#define sqlite3_mprintf                sqlite3_api->mprintf
+#define sqlite3_open                   sqlite3_api->open
+#define sqlite3_open16                 sqlite3_api->open16
+#define sqlite3_prepare                sqlite3_api->prepare
+#define sqlite3_prepare16              sqlite3_api->prepare16
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_profile                sqlite3_api->profile
+#define sqlite3_progress_handler       sqlite3_api->progress_handler
+#define sqlite3_realloc                sqlite3_api->realloc
+#define sqlite3_reset                  sqlite3_api->reset
+#define sqlite3_result_blob            sqlite3_api->result_blob
+#define sqlite3_result_double          sqlite3_api->result_double
+#define sqlite3_result_error           sqlite3_api->result_error
+#define sqlite3_result_error16         sqlite3_api->result_error16
+#define sqlite3_result_int             sqlite3_api->result_int
+#define sqlite3_result_int64           sqlite3_api->result_int64
+#define sqlite3_result_null            sqlite3_api->result_null
+#define sqlite3_result_text            sqlite3_api->result_text
+#define sqlite3_result_text16          sqlite3_api->result_text16
+#define sqlite3_result_text16be        sqlite3_api->result_text16be
+#define sqlite3_result_text16le        sqlite3_api->result_text16le
+#define sqlite3_result_value           sqlite3_api->result_value
+#define sqlite3_rollback_hook          sqlite3_api->rollback_hook
+#define sqlite3_set_authorizer         sqlite3_api->set_authorizer
+#define sqlite3_set_auxdata            sqlite3_api->set_auxdata
+#define sqlite3_snprintf               sqlite3_api->xsnprintf
+#define sqlite3_step                   sqlite3_api->step
+#define sqlite3_table_column_metadata  sqlite3_api->table_column_metadata
+#define sqlite3_thread_cleanup         sqlite3_api->thread_cleanup
+#define sqlite3_total_changes          sqlite3_api->total_changes
+#define sqlite3_trace                  sqlite3_api->trace
+#ifndef SQLITE_OMIT_DEPRECATED
+#define sqlite3_transfer_bindings      sqlite3_api->transfer_bindings
+#endif
+#define sqlite3_update_hook            sqlite3_api->update_hook
+#define sqlite3_user_data              sqlite3_api->user_data
+#define sqlite3_value_blob             sqlite3_api->value_blob
+#define sqlite3_value_bytes            sqlite3_api->value_bytes
+#define sqlite3_value_bytes16          sqlite3_api->value_bytes16
+#define sqlite3_value_double           sqlite3_api->value_double
+#define sqlite3_value_int              sqlite3_api->value_int
+#define sqlite3_value_int64            sqlite3_api->value_int64
+#define sqlite3_value_numeric_type     sqlite3_api->value_numeric_type
+#define sqlite3_value_text             sqlite3_api->value_text
+#define sqlite3_value_text16           sqlite3_api->value_text16
+#define sqlite3_value_text16be         sqlite3_api->value_text16be
+#define sqlite3_value_text16le         sqlite3_api->value_text16le
+#define sqlite3_value_type             sqlite3_api->value_type
+#define sqlite3_vmprintf               sqlite3_api->vmprintf
+#define sqlite3_vsnprintf              sqlite3_api->xvsnprintf
+#define sqlite3_overload_function      sqlite3_api->overload_function
+#define sqlite3_prepare_v2             sqlite3_api->prepare_v2
+#define sqlite3_prepare16_v2           sqlite3_api->prepare16_v2
+#define sqlite3_clear_bindings         sqlite3_api->clear_bindings
+#define sqlite3_bind_zeroblob          sqlite3_api->bind_zeroblob
+#define sqlite3_blob_bytes             sqlite3_api->blob_bytes
+#define sqlite3_blob_close             sqlite3_api->blob_close
+#define sqlite3_blob_open              sqlite3_api->blob_open
+#define sqlite3_blob_read              sqlite3_api->blob_read
+#define sqlite3_blob_write             sqlite3_api->blob_write
+#define sqlite3_create_collation_v2    sqlite3_api->create_collation_v2
+#define sqlite3_file_control           sqlite3_api->file_control
+#define sqlite3_memory_highwater       sqlite3_api->memory_highwater
+#define sqlite3_memory_used            sqlite3_api->memory_used
+#define sqlite3_mutex_alloc            sqlite3_api->mutex_alloc
+#define sqlite3_mutex_enter            sqlite3_api->mutex_enter
+#define sqlite3_mutex_free             sqlite3_api->mutex_free
+#define sqlite3_mutex_leave            sqlite3_api->mutex_leave
+#define sqlite3_mutex_try              sqlite3_api->mutex_try
+#define sqlite3_open_v2                sqlite3_api->open_v2
+#define sqlite3_release_memory         sqlite3_api->release_memory
+#define sqlite3_result_error_nomem     sqlite3_api->result_error_nomem
+#define sqlite3_result_error_toobig    sqlite3_api->result_error_toobig
+#define sqlite3_sleep                  sqlite3_api->sleep
+#define sqlite3_soft_heap_limit        sqlite3_api->soft_heap_limit
+#define sqlite3_vfs_find               sqlite3_api->vfs_find
+#define sqlite3_vfs_register           sqlite3_api->vfs_register
+#define sqlite3_vfs_unregister         sqlite3_api->vfs_unregister
+#define sqlite3_threadsafe             sqlite3_api->xthreadsafe
+#define sqlite3_result_zeroblob        sqlite3_api->result_zeroblob
+#define sqlite3_result_error_code      sqlite3_api->result_error_code
+#define sqlite3_test_control           sqlite3_api->test_control
+#define sqlite3_randomness             sqlite3_api->randomness
+#define sqlite3_context_db_handle      sqlite3_api->context_db_handle
+#define sqlite3_extended_result_codes  sqlite3_api->extended_result_codes
+#define sqlite3_limit                  sqlite3_api->limit
+#define sqlite3_next_stmt              sqlite3_api->next_stmt
+#define sqlite3_sql                    sqlite3_api->sql
+#define sqlite3_status                 sqlite3_api->status
+#define sqlite3_backup_finish          sqlite3_api->backup_finish
+#define sqlite3_backup_init            sqlite3_api->backup_init
+#define sqlite3_backup_pagecount       sqlite3_api->backup_pagecount
+#define sqlite3_backup_remaining       sqlite3_api->backup_remaining
+#define sqlite3_backup_step            sqlite3_api->backup_step
+#define sqlite3_compileoption_get      sqlite3_api->compileoption_get
+#define sqlite3_compileoption_used     sqlite3_api->compileoption_used
+#define sqlite3_create_function_v2     sqlite3_api->create_function_v2
+#define sqlite3_db_config              sqlite3_api->db_config
+#define sqlite3_db_mutex               sqlite3_api->db_mutex
+#define sqlite3_db_status              sqlite3_api->db_status
+#define sqlite3_extended_errcode       sqlite3_api->extended_errcode
+#define sqlite3_log                    sqlite3_api->log
+#define sqlite3_soft_heap_limit64      sqlite3_api->soft_heap_limit64
+#define sqlite3_sourceid               sqlite3_api->sourceid
+#define sqlite3_stmt_status            sqlite3_api->stmt_status
+#define sqlite3_strnicmp               sqlite3_api->strnicmp
+#define sqlite3_unlock_notify          sqlite3_api->unlock_notify
+#define sqlite3_wal_autocheckpoint     sqlite3_api->wal_autocheckpoint
+#define sqlite3_wal_checkpoint         sqlite3_api->wal_checkpoint
+#define sqlite3_wal_hook               sqlite3_api->wal_hook
+#define sqlite3_blob_reopen            sqlite3_api->blob_reopen
+#define sqlite3_vtab_config            sqlite3_api->vtab_config
+#define sqlite3_vtab_on_conflict       sqlite3_api->vtab_on_conflict
+/* Version 3.7.16 and later */
+#define sqlite3_close_v2               sqlite3_api->close_v2
+#define sqlite3_db_filename            sqlite3_api->db_filename
+#define sqlite3_db_readonly            sqlite3_api->db_readonly
+#define sqlite3_db_release_memory      sqlite3_api->db_release_memory
+#define sqlite3_errstr                 sqlite3_api->errstr
+#define sqlite3_stmt_busy              sqlite3_api->stmt_busy
+#define sqlite3_stmt_readonly          sqlite3_api->stmt_readonly
+#define sqlite3_stricmp                sqlite3_api->stricmp
+#define sqlite3_uri_boolean            sqlite3_api->uri_boolean
+#define sqlite3_uri_int64              sqlite3_api->uri_int64
+#define sqlite3_uri_parameter          sqlite3_api->uri_parameter
+#define sqlite3_uri_vsnprintf          sqlite3_api->xvsnprintf
+#define sqlite3_wal_checkpoint_v2      sqlite3_api->wal_checkpoint_v2
+/* Version 3.8.7 and later */
+#define sqlite3_auto_extension         sqlite3_api->auto_extension
+#define sqlite3_bind_blob64            sqlite3_api->bind_blob64
+#define sqlite3_bind_text64            sqlite3_api->bind_text64
+#define sqlite3_cancel_auto_extension  sqlite3_api->cancel_auto_extension
+#define sqlite3_load_extension         sqlite3_api->load_extension
+#define sqlite3_malloc64               sqlite3_api->malloc64
+#define sqlite3_msize                  sqlite3_api->msize
+#define sqlite3_realloc64              sqlite3_api->realloc64
+#define sqlite3_reset_auto_extension   sqlite3_api->reset_auto_extension
+#define sqlite3_result_blob64          sqlite3_api->result_blob64
+#define sqlite3_result_text64          sqlite3_api->result_text64
+#define sqlite3_strglob                sqlite3_api->strglob
+/* Version 3.8.11 and later */
+#define sqlite3_value_dup              sqlite3_api->value_dup
+#define sqlite3_value_free             sqlite3_api->value_free
+#define sqlite3_result_zeroblob64      sqlite3_api->result_zeroblob64
+#define sqlite3_bind_zeroblob64        sqlite3_api->bind_zeroblob64
+/* Version 3.9.0 and later */
+#define sqlite3_value_subtype          sqlite3_api->value_subtype
+#define sqlite3_result_subtype         sqlite3_api->result_subtype
+/* Version 3.10.0 and later */
+#define sqlite3_status64               sqlite3_api->status64
+#define sqlite3_strlike                sqlite3_api->strlike
+#define sqlite3_db_cacheflush          sqlite3_api->db_cacheflush
+/* Version 3.12.0 and later */
+#define sqlite3_system_errno           sqlite3_api->system_errno
+/* Version 3.14.0 and later */
+#define sqlite3_trace_v2               sqlite3_api->trace_v2
+#define sqlite3_expanded_sql           sqlite3_api->expanded_sql
+/* Version 3.18.0 and later */
+#define sqlite3_set_last_insert_rowid  sqlite3_api->set_last_insert_rowid
+/* Version 3.20.0 and later */
+#define sqlite3_prepare_v3             sqlite3_api->prepare_v3
+#define sqlite3_prepare16_v3           sqlite3_api->prepare16_v3
+#define sqlite3_bind_pointer           sqlite3_api->bind_pointer
+#define sqlite3_result_pointer         sqlite3_api->result_pointer
+#define sqlite3_value_pointer          sqlite3_api->value_pointer
+/* Version 3.22.0 and later */
+#define sqlite3_vtab_nochange          sqlite3_api->vtab_nochange
+#define sqlite3_value_nochange         sqlite3_api->value_nochange
+#define sqlite3_vtab_collation         sqlite3_api->vtab_collation
+/* Version 3.24.0 and later */
+#define sqlite3_keyword_count          sqlite3_api->keyword_count
+#define sqlite3_keyword_name           sqlite3_api->keyword_name
+#define sqlite3_keyword_check          sqlite3_api->keyword_check
+#define sqlite3_str_new                sqlite3_api->str_new
+#define sqlite3_str_finish             sqlite3_api->str_finish
+#define sqlite3_str_appendf            sqlite3_api->str_appendf
+#define sqlite3_str_vappendf           sqlite3_api->str_vappendf
+#define sqlite3_str_append             sqlite3_api->str_append
+#define sqlite3_str_appendall          sqlite3_api->str_appendall
+#define sqlite3_str_appendchar         sqlite3_api->str_appendchar
+#define sqlite3_str_reset              sqlite3_api->str_reset
+#define sqlite3_str_errcode            sqlite3_api->str_errcode
+#define sqlite3_str_length             sqlite3_api->str_length
+#define sqlite3_str_value              sqlite3_api->str_value
+/* Version 3.25.0 and later */
+#define sqlite3_create_window_function sqlite3_api->create_window_function
+/* Version 3.26.0 and later */
+#define sqlite3_normalized_sql         sqlite3_api->normalized_sql
+/* Version 3.28.0 and later */
+#define sqlite3_stmt_isexplain         sqlite3_api->stmt_isexplain
+#define sqlite3_value_frombind         sqlite3_api->value_frombind
+/* Version 3.30.0 and later */
+#define sqlite3_drop_modules           sqlite3_api->drop_modules
+/* Version 3.31.0 and later */
+#define sqlite3_hard_heap_limit64      sqlite3_api->hard_heap_limit64
+#define sqlite3_uri_key                sqlite3_api->uri_key
+#define sqlite3_filename_database      sqlite3_api->filename_database
+#define sqlite3_filename_journal       sqlite3_api->filename_journal
+#define sqlite3_filename_wal           sqlite3_api->filename_wal
+/* Version 3.32.0 and later */
+#define sqlite3_create_filename        sqlite3_api->create_filename
+#define sqlite3_free_filename          sqlite3_api->free_filename
+#define sqlite3_database_file_object   sqlite3_api->database_file_object
+/* Version 3.34.0 and later */
+#define sqlite3_txn_state              sqlite3_api->txn_state
+/* Version 3.36.1 and later */
+#define sqlite3_changes64              sqlite3_api->changes64
+#define sqlite3_total_changes64        sqlite3_api->total_changes64
+/* Version 3.37.0 and later */
+#define sqlite3_autovacuum_pages       sqlite3_api->autovacuum_pages
+/* Version 3.38.0 and later */
+#define sqlite3_error_offset           sqlite3_api->error_offset
+#define sqlite3_vtab_rhs_value         sqlite3_api->vtab_rhs_value
+#define sqlite3_vtab_distinct          sqlite3_api->vtab_distinct
+#define sqlite3_vtab_in                sqlite3_api->vtab_in
+#define sqlite3_vtab_in_first          sqlite3_api->vtab_in_first
+#define sqlite3_vtab_in_next           sqlite3_api->vtab_in_next
+/* Version 3.39.0 and later */
+#ifndef SQLITE_OMIT_DESERIALIZE
+#define sqlite3_deserialize            sqlite3_api->deserialize
+#define sqlite3_serialize              sqlite3_api->serialize
+#endif
+#define sqlite3_db_name                sqlite3_api->db_name
+/* Version 3.40.0 and later */
+#define sqlite3_value_encoding         sqlite3_api->value_encoding
+/* Version 3.41.0 and later */
+#define sqlite3_is_interrupted         sqlite3_api->is_interrupted
+/* Version 3.43.0 and later */
+#define sqlite3_stmt_explain           sqlite3_api->stmt_explain
+/* Version 3.44.0 and later */
+#define sqlite3_get_clientdata         sqlite3_api->get_clientdata
+#define sqlite3_set_clientdata         sqlite3_api->set_clientdata
+#endif /* !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION) */
+
+#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
+  /* This case when the file really is being compiled as a loadable 
+  ** extension */
+# define SQLITE_EXTENSION_INIT1     const sqlite3_api_routines *sqlite3_api=0;
+# define SQLITE_EXTENSION_INIT2(v)  sqlite3_api=v;
+# define SQLITE_EXTENSION_INIT3     \
+    extern const sqlite3_api_routines *sqlite3_api;
+#else
+  /* This case when the file is being statically linked into the 
+  ** application */
+# define SQLITE_EXTENSION_INIT1     /*no-op*/
+# define SQLITE_EXTENSION_INIT2(v)  (void)v; /* unused parameter */
+# define SQLITE_EXTENSION_INIT3     /*no-op*/
+#endif
+
+#endif /* SQLITE3EXT_H */
diff --git a/server/node_modules/better-sqlite3/deps/test_extension.c b/server/node_modules/better-sqlite3/deps/test_extension.c
new file mode 100644
index 0000000..540aad2
--- /dev/null
+++ b/server/node_modules/better-sqlite3/deps/test_extension.c
@@ -0,0 +1,21 @@
+#include <sqlite3ext.h>
+SQLITE_EXTENSION_INIT1
+
+/*
+	This SQLite extension is used only for testing purposes (npm test).
+ */
+
+static void TestExtensionFunction(sqlite3_context* pCtx, int nVal, sqlite3_value** _) {
+	sqlite3_result_double(pCtx, (double)nVal);
+}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+
+int sqlite3_extension_init(sqlite3* db, char** pzErrMsg, const sqlite3_api_routines* pApi) {
+	SQLITE_EXTENSION_INIT2(pApi)
+	if (pzErrMsg != 0) *pzErrMsg = 0;
+	sqlite3_create_function(db, "testExtensionFunction", -1, SQLITE_UTF8, 0, TestExtensionFunction, 0, 0);
+	return SQLITE_OK;
+}
diff --git a/server/node_modules/better-sqlite3/lib/database.js b/server/node_modules/better-sqlite3/lib/database.js
new file mode 100644
index 0000000..14e0573
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/database.js
@@ -0,0 +1,90 @@
+'use strict';
+const fs = require('fs');
+const path = require('path');
+const util = require('./util');
+const SqliteError = require('./sqlite-error');
+
+let DEFAULT_ADDON;
+
+function Database(filenameGiven, options) {
+	if (new.target == null) {
+		return new Database(filenameGiven, options);
+	}
+
+	// Apply defaults
+	let buffer;
+	if (Buffer.isBuffer(filenameGiven)) {
+		buffer = filenameGiven;
+		filenameGiven = ':memory:';
+	}
+	if (filenameGiven == null) filenameGiven = '';
+	if (options == null) options = {};
+
+	// Validate arguments
+	if (typeof filenameGiven !== 'string') throw new TypeError('Expected first argument to be a string');
+	if (typeof options !== 'object') throw new TypeError('Expected second argument to be an options object');
+	if ('readOnly' in options) throw new TypeError('Misspelled option "readOnly" should be "readonly"');
+	if ('memory' in options) throw new TypeError('Option "memory" was removed in v7.0.0 (use ":memory:" filename instead)');
+
+	// Interpret options
+	const filename = filenameGiven.trim();
+	const anonymous = filename === '' || filename === ':memory:';
+	const readonly = util.getBooleanOption(options, 'readonly');
+	const fileMustExist = util.getBooleanOption(options, 'fileMustExist');
+	const timeout = 'timeout' in options ? options.timeout : 5000;
+	const verbose = 'verbose' in options ? options.verbose : null;
+	const nativeBinding = 'nativeBinding' in options ? options.nativeBinding : null;
+
+	// Validate interpreted options
+	if (readonly && anonymous && !buffer) throw new TypeError('In-memory/temporary databases cannot be readonly');
+	if (!Number.isInteger(timeout) || timeout < 0) throw new TypeError('Expected the "timeout" option to be a positive integer');
+	if (timeout > 0x7fffffff) throw new RangeError('Option "timeout" cannot be greater than 2147483647');
+	if (verbose != null && typeof verbose !== 'function') throw new TypeError('Expected the "verbose" option to be a function');
+	if (nativeBinding != null && typeof nativeBinding !== 'string' && typeof nativeBinding !== 'object') throw new TypeError('Expected the "nativeBinding" option to be a string or addon object');
+
+	// Load the native addon
+	let addon;
+	if (nativeBinding == null) {
+		addon = DEFAULT_ADDON || (DEFAULT_ADDON = require('bindings')('better_sqlite3.node'));
+	} else if (typeof nativeBinding === 'string') {
+		// See <https://webpack.js.org/api/module-variables/#__non_webpack_require__-webpack-specific>
+		const requireFunc = typeof __non_webpack_require__ === 'function' ? __non_webpack_require__ : require;
+		addon = requireFunc(path.resolve(nativeBinding).replace(/(\.node)?$/, '.node'));
+	} else {
+		// See <https://github.com/WiseLibs/better-sqlite3/issues/972>
+		addon = nativeBinding;
+	}
+
+	if (!addon.isInitialized) {
+		addon.setErrorConstructor(SqliteError);
+		addon.isInitialized = true;
+	}
+
+	// Make sure the specified directory exists
+	if (!anonymous && !fs.existsSync(path.dirname(filename))) {
+		throw new TypeError('Cannot open database because the directory does not exist');
+	}
+
+	Object.defineProperties(this, {
+		[util.cppdb]: { value: new addon.Database(filename, filenameGiven, anonymous, readonly, fileMustExist, timeout, verbose || null, buffer || null) },
+		...wrappers.getters,
+	});
+}
+
+const wrappers = require('./methods/wrappers');
+Database.prototype.prepare = wrappers.prepare;
+Database.prototype.transaction = require('./methods/transaction');
+Database.prototype.pragma = require('./methods/pragma');
+Database.prototype.backup = require('./methods/backup');
+Database.prototype.serialize = require('./methods/serialize');
+Database.prototype.function = require('./methods/function');
+Database.prototype.aggregate = require('./methods/aggregate');
+Database.prototype.table = require('./methods/table');
+Database.prototype.loadExtension = wrappers.loadExtension;
+Database.prototype.exec = wrappers.exec;
+Database.prototype.close = wrappers.close;
+Database.prototype.defaultSafeIntegers = wrappers.defaultSafeIntegers;
+Database.prototype.unsafeMode = wrappers.unsafeMode;
+Database.prototype[util.inspect] = require('./methods/inspect');
+
+module.exports = Database;
diff --git a/server/node_modules/better-sqlite3/lib/index.js b/server/node_modules/better-sqlite3/lib/index.js
new file mode 100644
index 0000000..a66e32e
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/index.js
@@ -0,0 +1,3 @@
+'use strict';
+module.exports = require('./database');
+module.exports.SqliteError = require('./sqlite-error');
diff --git a/server/node_modules/better-sqlite3/lib/methods/aggregate.js b/server/node_modules/better-sqlite3/lib/methods/aggregate.js
new file mode 100644
index 0000000..0417362
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/methods/aggregate.js
@@ -0,0 +1,43 @@
+'use strict';
+const { getBooleanOption, cppdb } = require('../util');
+
+module.exports = function defineAggregate(name, options) {
+	// Validate arguments
+	if (typeof name !== 'string') throw new TypeError('Expected first argument to be a string');
+	if (typeof options !== 'object' || options === null) throw new TypeError('Expected second argument to be an options object');
+	if (!name) throw new TypeError('User-defined function name cannot be an empty string');
+
+	// Interpret options
+	const start = 'start' in options ? options.start : null;
+	const step = getFunctionOption(options, 'step', true);
+	const inverse = getFunctionOption(options, 'inverse', false);
+	const result = getFunctionOption(options, 'result', false);
+	const safeIntegers = 'safeIntegers' in options ? +getBooleanOption(options, 'safeIntegers') : 2;
+	const deterministic = getBooleanOption(options, 'deterministic');
+	const directOnly = getBooleanOption(options, 'directOnly');
+	const varargs = getBooleanOption(options, 'varargs');
+	let argCount = -1;
+
+	// Determine argument count
+	if (!varargs) {
+		argCount = Math.max(getLength(step), inverse ? getLength(inverse) : 0);
+		if (argCount > 0) argCount -= 1;
+		if (argCount > 100) throw new RangeError('User-defined functions cannot have more than 100 arguments');
+	}
+
+	this[cppdb].aggregate(start, step, inverse, result, name, argCount, safeIntegers, deterministic, directOnly);
+	return this;
+};
+
+const getFunctionOption = (options, key, required) => {
+	const value = key in options ? options[key] : null;
+	if (typeof value === 'function') return value;
+	if (value != null) throw new TypeError(`Expected the "${key}" option to be a function`);
+	if (required) throw new TypeError(`Missing required option "${key}"`);
+	return null;
+};
+
+const getLength = ({ length }) => {
+	if (Number.isInteger(length) && length >= 0) return length;
+	throw new TypeError('Expected function.length to be a positive integer');
+};
diff --git a/server/node_modules/better-sqlite3/lib/methods/backup.js b/server/node_modules/better-sqlite3/lib/methods/backup.js
new file mode 100644
index 0000000..fe541b7
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/methods/backup.js
@@ -0,0 +1,67 @@
+'use strict';
+const fs = require('fs');
+const path = require('path');
+const { promisify } = require('util');
+const { cppdb } = require('../util');
+const fsAccess = promisify(fs.access);
+
+module.exports = async function backup(filename, options) {
+	if (options == null) options = {};
+
+	// Validate arguments
+	if (typeof filename !== 'string') throw new TypeError('Expected first argument to be a string');
+	if (typeof options !== 'object') throw new TypeError('Expected second argument to be an options object');
+
+	// Interpret options
+	filename = filename.trim();
+	const attachedName = 'attached' in options ? options.attached : 'main';
+	const handler = 'progress' in options ? options.progress : null;
+
+	// Validate interpreted options
+	if (!filename) throw new TypeError('Backup filename cannot be an empty string');
+	if (filename === ':memory:') throw new TypeError('Invalid backup filename ":memory:"');
+	if (typeof attachedName !== 'string') throw new TypeError('Expected the "attached" option to be a string');
+	if (!attachedName) throw new TypeError('The "attached" option cannot be an empty string');
+	if (handler != null && typeof handler !== 'function') throw new TypeError('Expected the "progress" option to be a function');
+
+	// Make sure the specified directory exists
+	await fsAccess(path.dirname(filename)).catch(() => {
+		throw new TypeError('Cannot save backup because the directory does not exist');
+	});
+
+	const isNewFile = await fsAccess(filename).then(() => false, () => true);
+	return runBackup(this[cppdb].backup(this, attachedName, filename, isNewFile), handler || null);
+};
+
+const runBackup = (backup, handler) => {
+	let rate = 0;
+	let useDefault = true;
+
+	return new Promise((resolve, reject) => {
+		setImmediate(function step() {
+			try {
+				const progress = backup.transfer(rate);
+				if (!progress.remainingPages) {
+					backup.close();
+					resolve(progress);
+					return;
+				}
+				if (useDefault) {
+					useDefault = false;
+					rate = 100;
+				}
+				if (handler) {
+					const ret = handler(progress);
+					if (ret !== undefined) {
+						if (typeof ret === 'number' && ret === ret) rate = Math.max(0, Math.min(0x7fffffff, Math.round(ret)));
+						else throw new TypeError('Expected progress callback to return a number or undefined');
+					}
+				}
+				setImmediate(step);
+			} catch (err) {
+				backup.close();
+				reject(err);
+			}
+		});
+	});
+};
diff --git a/server/node_modules/better-sqlite3/lib/methods/function.js b/server/node_modules/better-sqlite3/lib/methods/function.js
new file mode 100644
index 0000000..f4406d4
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/methods/function.js
@@ -0,0 +1,31 @@
+'use strict';
+const { getBooleanOption, cppdb } = require('../util');
+
+module.exports = function defineFunction(name, options, fn) {
+	// Apply defaults
+	if (options == null) options = {};
+	if (typeof options === 'function') { fn = options; options = {}; }
+
+	// Validate arguments
+	if (typeof name !== 'string') throw new TypeError('Expected first argument to be a string');
+	if (typeof fn !== 'function') throw new TypeError('Expected last argument to be a function');
+	if (typeof options !== 'object') throw new TypeError('Expected second argument to be an options object');
+	if (!name) throw new TypeError('User-defined function name cannot be an empty string');
+
+	// Interpret options
+	const safeIntegers = 'safeIntegers' in options ? +getBooleanOption(options, 'safeIntegers') : 2;
+	const deterministic = getBooleanOption(options, 'deterministic');
+	const directOnly = getBooleanOption(options, 'directOnly');
+	const varargs = getBooleanOption(options, 'varargs');
+	let argCount = -1;
+
+	// Determine argument count
+	if (!varargs) {
+		argCount = fn.length;
+		if (!Number.isInteger(argCount) || argCount < 0) throw new TypeError('Expected function.length to be a positive integer');
+		if (argCount > 100) throw new RangeError('User-defined functions cannot have more than 100 arguments');
+	}
+
+	this[cppdb].function(fn, name, argCount, safeIntegers, deterministic, directOnly);
+	return this;
+};
diff --git a/server/node_modules/better-sqlite3/lib/methods/inspect.js b/server/node_modules/better-sqlite3/lib/methods/inspect.js
new file mode 100644
index 0000000..cd9fd6d
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/methods/inspect.js
@@ -0,0 +1,7 @@
+'use strict';
+const DatabaseInspection = function Database() {};
+
+module.exports = function inspect(depth, opts) {
+	return Object.assign(new DatabaseInspection(), this);
+};
+
diff --git a/server/node_modules/better-sqlite3/lib/methods/pragma.js b/server/node_modules/better-sqlite3/lib/methods/pragma.js
new file mode 100644
index 0000000..a275ab0
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/methods/pragma.js
@@ -0,0 +1,12 @@
+'use strict';
+const { getBooleanOption, cppdb } = require('../util');
+
+module.exports = function pragma(source, options) {
+	if (options == null) options = {};
+	if (typeof source !== 'string') throw new TypeError('Expected first argument to be a string');
+	if (typeof options !== 'object') throw new TypeError('Expected second argument to be an options object');
+	const simple = getBooleanOption(options, 'simple');
+
+	const stmt = this[cppdb].prepare(`PRAGMA ${source}`, this, true);
+	return simple ? stmt.pluck().get() : stmt.all();
+};
diff --git a/server/node_modules/better-sqlite3/lib/methods/serialize.js b/server/node_modules/better-sqlite3/lib/methods/serialize.js
new file mode 100644
index 0000000..4f1374f
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/methods/serialize.js
@@ -0,0 +1,16 @@
+'use strict';
+const { cppdb } = require('../util');
+
+module.exports = function serialize(options) {
+	if (options == null) options = {};
+
+	// Validate arguments
+	if (typeof options !== 'object') throw new TypeError('Expected first argument to be an options object');
+
+	// Interpret and validate options
+	const attachedName = 'attached' in options ? options.attached : 'main';
+	if (typeof attachedName !== 'string') throw new TypeError('Expected the "attached" option to be a string');
+	if (!attachedName) throw new TypeError('The "attached" option cannot be an empty string');
+
+	return this[cppdb].serialize(attachedName);
+};
diff --git a/server/node_modules/better-sqlite3/lib/methods/table.js b/server/node_modules/better-sqlite3/lib/methods/table.js
new file mode 100644
index 0000000..eac658e
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/methods/table.js
@@ -0,0 +1,189 @@
+'use strict';
+const { cppdb } = require('../util');
+
+module.exports = function defineTable(name, factory) {
+	// Validate arguments
+	if (typeof name !== 'string') throw new TypeError('Expected first argument to be a string');
+	if (!name) throw new TypeError('Virtual table module name cannot be an empty string');
+
+	// Determine whether the module is eponymous-only or not
+	let eponymous = false;
+	if (typeof factory === 'object' && factory !== null) {
+		eponymous = true;
+		factory = defer(parseTableDefinition(factory, 'used', name));
+	} else {
+		if (typeof factory !== 'function') throw new TypeError('Expected second argument to be a function or a table definition object');
+		factory = wrapFactory(factory);
+	}
+
+	this[cppdb].table(factory, name, eponymous);
+	return this;
+};
+
+function wrapFactory(factory) {
+	return function virtualTableFactory(moduleName, databaseName, tableName, ...args) {
+		const thisObject = {
+			module: moduleName,
+			database: databaseName,
+			table: tableName,
+		};
+
+		// Generate a new table definition by invoking the factory
+		const def = apply.call(factory, thisObject, args);
+		if (typeof def !== 'object' || def === null) {
+			throw new TypeError(`Virtual table module "${moduleName}" did not return a table definition object`);
+		}
+
+		return parseTableDefinition(def, 'returned', moduleName);
+	};
+}
+
+function parseTableDefinition(def, verb, moduleName) {
+	// Validate required properties
+	if (!hasOwnProperty.call(def, 'rows')) {
+		throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition without a "rows" property`);
+	}
+	if (!hasOwnProperty.call(def, 'columns')) {
+		throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition without a "columns" property`);
+	}
+
+	// Validate "rows" property
+	const rows = def.rows;
+	if (typeof rows !== 'function' || Object.getPrototypeOf(rows) !== GeneratorFunctionPrototype) {
+		throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition with an invalid "rows" property (should be a generator function)`);
+	}
+
+	// Validate "columns" property
+	let columns = def.columns;
+	if (!Array.isArray(columns) || !(columns = [...columns]).every(x => typeof x === 'string')) {
+		throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition with an invalid "columns" property (should be an array of strings)`);
+	}
+	if (columns.length !== new Set(columns).size) {
+		throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition with duplicate column names`);
+	}
+	if (!columns.length) {
+		throw new RangeError(`Virtual table module "${moduleName}" ${verb} a table definition with zero columns`);
+	}
+
+	// Validate "parameters" property
+	let parameters;
+	if (hasOwnProperty.call(def, 'parameters')) {
+		parameters = def.parameters;
+		if (!Array.isArray(parameters) || !(parameters = [...parameters]).every(x => typeof x === 'string')) {
+			throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition with an invalid "parameters" property (should be an array of strings)`);
+		}
+	} else {
+		parameters = inferParameters(rows);
+	}
+	if (parameters.length !== new Set(parameters).size) {
+		throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition with duplicate parameter names`);
+	}
+	if (parameters.length > 32) {
+		throw new RangeError(`Virtual table module "${moduleName}" ${verb} a table definition with more than the maximum number of 32 parameters`);
+	}
+	for (const parameter of parameters) {
+		if (columns.includes(parameter)) {
+			throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition with column "${parameter}" which was ambiguously defined as both a column and parameter`);
+		}
+	}
+
+	// Validate "safeIntegers" option
+	let safeIntegers = 2;
+	if (hasOwnProperty.call(def, 'safeIntegers')) {
+		const bool = def.safeIntegers;
+		if (typeof bool !== 'boolean') {
+			throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition with an invalid "safeIntegers" property (should be a boolean)`);
+		}
+		safeIntegers = +bool;
+	}
+
+	// Validate "directOnly" option
+	let directOnly = false;
+	if (hasOwnProperty.call(def, 'directOnly')) {
+		directOnly = def.directOnly;
+		if (typeof directOnly !== 'boolean') {
+			throw new TypeError(`Virtual table module "${moduleName}" ${verb} a table definition with an invalid "directOnly" property (should be a boolean)`);
+		}
+	}
+
+	// Generate SQL for the virtual table definition
+	const columnDefinitions = [
+		...parameters.map(identifier).map(str => `${str} HIDDEN`),
+		...columns.map(identifier),
+	];
+	return [
+		`CREATE TABLE x(${columnDefinitions.join(', ')});`,
+		wrapGenerator(rows, new Map(columns.map((x, i) => [x, parameters.length + i])), moduleName),
+		parameters,
+		safeIntegers,
+		directOnly,
+	];
+}
+
+function wrapGenerator(generator, columnMap, moduleName) {
+	return function* virtualTable(...args) {
+		/*
+			We must defensively clone any buffers in the arguments, because
+			otherwise the generator could mutate one of them, which would cause
+			us to return incorrect values for hidden columns, potentially
+			corrupting the database.
+		 */
+		const output = args.map(x => Buffer.isBuffer(x) ? Buffer.from(x) : x);
+		for (let i = 0; i < columnMap.size; ++i) {
+			output.push(null); // Fill with nulls to prevent gaps in array (v8 optimization)
+		}
+		for (const row of generator(...args)) {
+			if (Array.isArray(row)) {
+				extractRowArray(row, output, columnMap.size, moduleName);
+				yield output;
+			} else if (typeof row === 'object' && row !== null) {
+				extractRowObject(row, output, columnMap, moduleName);
+				yield output;
+			} else {
+				throw new TypeError(`Virtual table module "${moduleName}" yielded something that isn't a valid row object`);
+			}
+		}
+	};
+}
+
+function extractRowArray(row, output, columnCount, moduleName) {
+	if (row.length !== columnCount) {
+		throw new TypeError(`Virtual table module "${moduleName}" yielded a row with an incorrect number of columns`);
+	}
+	const offset = output.length - columnCount;
+	for (let i = 0; i < columnCount; ++i) {
+		output[i + offset] = row[i];
+	}
+}
+
+function extractRowObject(row, output, columnMap, moduleName) {
+	let count = 0;
+	for (const key of Object.keys(row)) {
+		const index = columnMap.get(key);
+		if (index === undefined) {
+			throw new TypeError(`Virtual table module "${moduleName}" yielded a row with an undeclared column "${key}"`);
+		}
+		output[index] = row[key];
+		count += 1;
+	}
+	if (count !== columnMap.size) {
+		throw new TypeError(`Virtual table module "${moduleName}" yielded a row with missing columns`);
+	}
+}
+
+function inferParameters({ length }) {
+	if (!Number.isInteger(length) || length < 0) {
+		throw new TypeError('Expected function.length to be a positive integer');
+	}
+	const params = [];
+	for (let i = 0; i < length; ++i) {
+		params.push(`$${i + 1}`);
+	}
+	return params;
+}
+
+const { hasOwnProperty } = Object.prototype;
+const { apply } = Function.prototype;
+const GeneratorFunctionPrototype = Object.getPrototypeOf(function*(){});
+const identifier = str => `"${str.replace(/"/g, '""')}"`;
+const defer = x => () => x;
diff --git a/server/node_modules/better-sqlite3/lib/methods/transaction.js b/server/node_modules/better-sqlite3/lib/methods/transaction.js
new file mode 100644
index 0000000..cb6c5e9
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/methods/transaction.js
@@ -0,0 +1,78 @@
+'use strict';
+const { cppdb } = require('../util');
+const controllers = new WeakMap();
+
+module.exports = function transaction(fn) {
+	if (typeof fn !== 'function') throw new TypeError('Expected first argument to be a function');
+
+	const db = this[cppdb];
+	const controller = getController(db, this);
+	const { apply } = Function.prototype;
+
+	// Each version of the transaction function has these same properties
+	const properties = {
+		default: { value: wrapTransaction(apply, fn, db, controller.default) },
+		deferred: { value: wrapTransaction(apply, fn, db, controller.deferred) },
+		immediate: { value: wrapTransaction(apply, fn, db, controller.immediate) },
+		exclusive: { value: wrapTransaction(apply, fn, db, controller.exclusive) },
+		database: { value: this, enumerable: true },
+	};
+
+	Object.defineProperties(properties.default.value, properties);
+	Object.defineProperties(properties.deferred.value, properties);
+	Object.defineProperties(properties.immediate.value, properties);
+	Object.defineProperties(properties.exclusive.value, properties);
+
+	// Return the default version of the transaction function
+	return properties.default.value;
+};
+
+// Return the database's cached transaction controller, or create a new one
+const getController = (db, self) => {
+	let controller = controllers.get(db);
+	if (!controller) {
+		const shared = {
+			commit: db.prepare('COMMIT', self, false),
+			rollback: db.prepare('ROLLBACK', self, false),
+			savepoint: db.prepare('SAVEPOINT `\t_bs3.\t`', self, false),
+			release: db.prepare('RELEASE `\t_bs3.\t`', self, false),
+			rollbackTo: db.prepare('ROLLBACK TO `\t_bs3.\t`', self, false),
+		};
+		controllers.set(db, controller = {
+			default: Object.assign({ begin: db.prepare('BEGIN', self, false) }, shared),
+			deferred: Object.assign({ begin: db.prepare('BEGIN DEFERRED', self, false) }, shared),
+			immediate: Object.assign({ begin: db.prepare('BEGIN IMMEDIATE', self, false) }, shared),
+			exclusive: Object.assign({ begin: db.prepare('BEGIN EXCLUSIVE', self, false) }, shared),
+		});
+	}
+	return controller;
+};
+
+// Return a new transaction function by wrapping the given function
+const wrapTransaction = (apply, fn, db, { begin, commit, rollback, savepoint, release, rollbackTo }) => function sqliteTransaction() {
+	let before, after, undo;
+	if (db.inTransaction) {
+		before = savepoint;
+		after = release;
+		undo = rollbackTo;
+	} else {
+		before = begin;
+		after = commit;
+		undo = rollback;
+	}
+	before.run();
+	try {
+		const result = apply.call(fn, this, arguments);
+		if (result && typeof result.then === 'function') {
+			throw new TypeError('Transaction function cannot return a promise');
+		}
+		after.run();
+		return result;
+	} catch (ex) {
+		if (db.inTransaction) {
+			undo.run();
+			if (undo !== rollback) after.run();
+		}
+		throw ex;
+	}
+};
diff --git a/server/node_modules/better-sqlite3/lib/methods/wrappers.js b/server/node_modules/better-sqlite3/lib/methods/wrappers.js
new file mode 100644
index 0000000..1d4673e
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/methods/wrappers.js
@@ -0,0 +1,54 @@
+'use strict';
+const { cppdb } = require('../util');
+
+exports.prepare = function prepare(sql) {
+	return this[cppdb].prepare(sql, this, false);
+};
+
+exports.exec = function exec(sql) {
+	this[cppdb].exec(sql);
+	return this;
+};
+
+exports.close = function close() {
+	this[cppdb].close();
+	return this;
+};
+
+exports.loadExtension = function loadExtension(...args) {
+	this[cppdb].loadExtension(...args);
+	return this;
+};
+
+exports.defaultSafeIntegers = function defaultSafeIntegers(...args) {
+	this[cppdb].defaultSafeIntegers(...args);
+	return this;
+};
+
+exports.unsafeMode = function unsafeMode(...args) {
+	this[cppdb].unsafeMode(...args);
+	return this;
+};
+
+exports.getters = {
+	name: {
+		get: function name() { return this[cppdb].name; },
+		enumerable: true,
+	},
+	open: {
+		get: function open() { return this[cppdb].open; },
+		enumerable: true,
+	},
+	inTransaction: {
+		get: function inTransaction() { return this[cppdb].inTransaction; },
+		enumerable: true,
+	},
+	readonly: {
+		get: function readonly() { return this[cppdb].readonly; },
+		enumerable: true,
+	},
+	memory: {
+		get: function memory() { return this[cppdb].memory; },
+		enumerable: true,
+	},
+};
diff --git a/server/node_modules/better-sqlite3/lib/sqlite-error.js b/server/node_modules/better-sqlite3/lib/sqlite-error.js
new file mode 100644
index 0000000..28a9a18
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/sqlite-error.js
@@ -0,0 +1,20 @@
+'use strict';
+const descriptor = { value: 'SqliteError', writable: true, enumerable: false, configurable: true };
+
+function SqliteError(message, code) {
+	if (new.target !== SqliteError) {
+		return new SqliteError(message, code);
+	}
+	if (typeof code !== 'string') {
+		throw new TypeError('Expected second argument to be a string');
+	}
+	Error.call(this, message);
+	descriptor.value = '' + message;
+	Object.defineProperty(this, 'message', descriptor);
+	Error.captureStackTrace(this, SqliteError);
+	this.code = code;
+}
+Object.setPrototypeOf(SqliteError, Error);
+Object.setPrototypeOf(SqliteError.prototype, Error.prototype);
+Object.defineProperty(SqliteError.prototype, 'name', descriptor);
+module.exports = SqliteError;
diff --git a/server/node_modules/better-sqlite3/lib/util.js b/server/node_modules/better-sqlite3/lib/util.js
new file mode 100644
index 0000000..0328c84
--- /dev/null
+++ b/server/node_modules/better-sqlite3/lib/util.js
@@ -0,0 +1,12 @@
+'use strict';
+
+exports.getBooleanOption = (options, key) => {
+	let value = false;
+	if (key in options && typeof (value = options[key]) !== 'boolean') {
+		throw new TypeError(`Expected the "${key}" option to be a boolean`);
+	}
+	return value;
+};
+
+exports.cppdb = Symbol();
+exports.inspect = Symbol.for('nodejs.util.inspect.custom');
diff --git a/server/node_modules/better-sqlite3/package.json b/server/node_modules/better-sqlite3/package.json
new file mode 100644
index 0000000..59fdbb3
--- /dev/null
+++ b/server/node_modules/better-sqlite3/package.json
@@ -0,0 +1,54 @@
+{
+  "name": "better-sqlite3",
+  "version": "11.10.0",
+  "description": "The fastest and simplest library for SQLite in Node.js.",
+  "homepage": "http://github.com/WiseLibs/better-sqlite3",
+  "author": "Joshua Wise <joshuathomaswise@gmail.com>",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/WiseLibs/better-sqlite3.git"
+  },
+  "main": "lib/index.js",
+  "files": [
+    "binding.gyp",
+    "src/*.[ch]pp",
+    "lib/**",
+    "deps/**"
+  ],
+  "dependencies": {
+    "bindings": "^1.5.0",
+    "prebuild-install": "^7.1.1"
+  },
+  "devDependencies": {
+    "chai": "^4.3.8",
+    "cli-color": "^2.0.3",
+    "fs-extra": "^11.1.1",
+    "mocha": "^10.2.0",
+    "nodemark": "^0.3.0",
+    "prebuild": "^13.0.1",
+    "sqlite": "^5.0.1",
+    "sqlite3": "^5.1.6"
+  },
+  "scripts": {
+    "install": "prebuild-install || node-gyp rebuild --release",
+    "build-release": "node-gyp rebuild --release",
+    "build-debug": "node-gyp rebuild --debug",
+    "rebuild-release": "npm run lzz && npm run build-release",
+    "rebuild-debug": "npm run lzz && npm run build-debug",
+    "test": "mocha --exit --slow=75 --timeout=5000",
+    "benchmark": "node benchmark",
+    "download": "bash ./deps/download.sh",
+    "lzz": "lzz -hx hpp -sx cpp -k BETTER_SQLITE3 -d -hl -sl -e ./src/better_sqlite3.lzz"
+  },
+  "license": "MIT",
+  "keywords": [
+    "sql",
+    "sqlite",
+    "sqlite3",
+    "transactions",
+    "user-defined functions",
+    "aggregate functions",
+    "window functions",
+    "database"
+  ]
+}
diff --git a/server/node_modules/better-sqlite3/src/better_sqlite3.cpp b/server/node_modules/better-sqlite3/src/better_sqlite3.cpp
new file mode 100644
index 0000000..8fe2c68
--- /dev/null
+++ b/server/node_modules/better-sqlite3/src/better_sqlite3.cpp
@@ -0,0 +1,2186 @@
+// better_sqlite3.cpp
+//
+
+#include "better_sqlite3.hpp"
+#line 154 "./src/util/macros.lzz"
+void SetPrototypeGetter(
+	v8::Isolate* isolate,
+	v8::Local<v8::External> data,
+	v8::Local<v8::FunctionTemplate> recv,
+	const char* name,
+	v8::AccessorNameGetterCallback func
+) {
+	v8::HandleScope scope(isolate);
+
+	#if defined NODE_MODULE_VERSION && NODE_MODULE_VERSION < 121
+	recv->InstanceTemplate()->SetAccessor(
+		InternalizedFromLatin1(isolate, name),
+		func,
+		0,
+		data,
+		v8::AccessControl::DEFAULT,
+		v8::PropertyAttribute::None
+	);
+	#else
+	recv->InstanceTemplate()->SetNativeDataProperty(
+		InternalizedFromLatin1(isolate, name),
+		func,
+		0,
+		data
+	);
+	#endif
+}
+#line 184 "./src/util/macros.lzz"
+#ifndef V8_COMPRESS_POINTERS_IN_SHARED_CAGE
+#define SAFE_NEW_BUFFER(env, data, length, finalizeCallback, finalizeHint) node::Buffer::New(env, data, length, finalizeCallback, finalizeHint)
+#else
+static inline v8::MaybeLocal<v8::Object> BufferSandboxNew(v8::Isolate* isolate, char* data, size_t length, void (*finalizeCallback)(char*, void*), void* finalizeHint) {
+	v8::MaybeLocal<v8::Object> buffer = node::Buffer::Copy(isolate, data, length);
+	finalizeCallback(data, finalizeHint);
+	return buffer;
+}
+#define SAFE_NEW_BUFFER(env, data, length, finalizeCallback, finalizeHint) BufferSandboxNew(env, data, length, finalizeCallback, finalizeHint)
+#endif
+#line 39 "./src/util/binder.lzz"
+	static bool IsPlainObject(v8::Isolate* isolate, v8::Local<v8::Object> obj) {
+		v8::Local<v8::Value> proto = obj->GetPrototype();
+
+		#if defined NODE_MODULE_VERSION && NODE_MODULE_VERSION < 93
+		v8::Local<v8::Context> ctx = obj->CreationContext();
+		#else
+		v8::Local<v8::Context> ctx = obj->GetCreationContext().ToLocalChecked();
+		#endif
+
+		ctx->Enter();
+		v8::Local<v8::Value> baseProto = v8::Object::New(isolate)->GetPrototype();
+		ctx->Exit();
+		return proto->StrictEquals(baseProto) || proto->StrictEquals(v8::Null(isolate));
+	}
+#line 67 "./src/better_sqlite3.lzz"
+NODE_MODULE_INIT(/* exports, context */) {
+	v8::Isolate* isolate = context->GetIsolate();
+	v8::HandleScope scope(isolate);
+
+	// Initialize addon instance.
+	Addon* addon = new Addon(isolate);
+	v8::Local<v8::External> data = v8::External::New(isolate, addon);
+	node::AddEnvironmentCleanupHook(isolate, Addon::Cleanup, addon);
+
+	// Create and export native-backed classes and functions.
+	exports->Set(context, InternalizedFromLatin1(isolate, "Database"), Database::Init(isolate, data)).FromJust();
+	exports->Set(context, InternalizedFromLatin1(isolate, "Statement"), Statement::Init(isolate, data)).FromJust();
+	exports->Set(context, InternalizedFromLatin1(isolate, "StatementIterator"), StatementIterator::Init(isolate, data)).FromJust();
+	exports->Set(context, InternalizedFromLatin1(isolate, "Backup"), Backup::Init(isolate, data)).FromJust();
+	exports->Set(context, InternalizedFromLatin1(isolate, "setErrorConstructor"), v8::FunctionTemplate::New(isolate, Addon::JS_setErrorConstructor, data)->GetFunction(context).ToLocalChecked()).FromJust();
+
+	// Store addon instance data.
+	addon->Statement.Reset(isolate, exports->Get(context, InternalizedFromLatin1(isolate, "Statement")).ToLocalChecked().As<v8::Function>());
+	addon->StatementIterator.Reset(isolate, exports->Get(context, InternalizedFromLatin1(isolate, "StatementIterator")).ToLocalChecked().As<v8::Function>());
+	addon->Backup.Reset(isolate, exports->Get(context, InternalizedFromLatin1(isolate, "Backup")).ToLocalChecked().As<v8::Function>());
+}
+#define LZZ_INLINE inline
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 67 "./src/util/data.lzz"
+  static char const FLAT = 0;
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 68 "./src/util/data.lzz"
+  static char const PLUCK = 1;
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 69 "./src/util/data.lzz"
+  static char const EXPAND = 2;
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 70 "./src/util/data.lzz"
+  static char const RAW = 3;
+}
+#line 38 "./src/util/macros.lzz"
+void ThrowError (char const * message)
+#line 38 "./src/util/macros.lzz"
+                                     { v8 :: Isolate * isolate = v8 :: Isolate :: GetCurrent ( ) ; isolate->ThrowException(v8::Exception::Error(StringFromUtf8(isolate, message, -1)));
+}
+#line 39 "./src/util/macros.lzz"
+void ThrowTypeError (char const * message)
+#line 39 "./src/util/macros.lzz"
+                                         { v8 :: Isolate * isolate = v8 :: Isolate :: GetCurrent ( ) ; isolate->ThrowException(v8::Exception::TypeError(StringFromUtf8(isolate, message, -1)));
+}
+#line 40 "./src/util/macros.lzz"
+void ThrowRangeError (char const * message)
+#line 40 "./src/util/macros.lzz"
+                                          { v8 :: Isolate * isolate = v8 :: Isolate :: GetCurrent ( ) ; isolate->ThrowException(v8::Exception::RangeError(StringFromUtf8(isolate, message, -1)));
+}
+#line 106 "./src/util/macros.lzz"
+v8::Local <v8::FunctionTemplate> NewConstructorTemplate (v8::Isolate * isolate, v8::Local <v8::External> data, v8::FunctionCallback func, char const * name)
+#line 111 "./src/util/macros.lzz"
+  {
+        v8::Local<v8::FunctionTemplate> t = v8::FunctionTemplate::New(isolate, func, data);
+        t->InstanceTemplate()->SetInternalFieldCount(1);
+        t->SetClassName(InternalizedFromLatin1(isolate, name));
+        return t;
+}
+#line 117 "./src/util/macros.lzz"
+void SetPrototypeMethod (v8::Isolate * isolate, v8::Local <v8::External> data, v8::Local <v8::FunctionTemplate> recv, char const * name, v8::FunctionCallback func)
+#line 123 "./src/util/macros.lzz"
+  {
+        v8::HandleScope scope(isolate);
+        recv->PrototypeTemplate()->Set(
+                InternalizedFromLatin1(isolate, name),
+                v8::FunctionTemplate::New(isolate, func, data, v8::Signature::New(isolate, recv))
+        );
+}
+#line 130 "./src/util/macros.lzz"
+void SetPrototypeSymbolMethod (v8::Isolate * isolate, v8::Local <v8::External> data, v8::Local <v8::FunctionTemplate> recv, v8::Local <v8::Symbol> symbol, v8::FunctionCallback func)
+#line 136 "./src/util/macros.lzz"
+  {
+        v8::HandleScope scope(isolate);
+        recv->PrototypeTemplate()->Set(
+                symbol,
+                v8::FunctionTemplate::New(isolate, func, data, v8::Signature::New(isolate, recv))
+        );
+}
+#line 4 "./src/util/constants.lzz"
+v8::Local <v8::String> CS::Code (v8::Isolate * isolate, int code)
+#line 4 "./src/util/constants.lzz"
+                                                                   {
+                auto element = codes.find(code);
+                if (element != codes.end()) return element->second.Get(isolate);
+                return StringFromUtf8(isolate, (std::string("UNKNOWN_SQLITE_ERROR_") + std::to_string(code)).c_str(), -1);
+}
+#line 10 "./src/util/constants.lzz"
+CS::CS (v8::Isolate * isolate)
+#line 10 "./src/util/constants.lzz"
+                                          {
+                SetString(isolate, database, "database");
+                SetString(isolate, reader, "reader");
+                SetString(isolate, source, "source");
+                SetString(isolate, memory, "memory");
+                SetString(isolate, readonly, "readonly");
+                SetString(isolate, name, "name");
+                SetString(isolate, next, "next");
+                SetString(isolate, length, "length");
+                SetString(isolate, done, "done");
+                SetString(isolate, value, "value");
+                SetString(isolate, changes, "changes");
+                SetString(isolate, lastInsertRowid, "lastInsertRowid");
+                SetString(isolate, statement, "statement");
+                SetString(isolate, column, "column");
+                SetString(isolate, table, "table");
+                SetString(isolate, type, "type");
+                SetString(isolate, totalPages, "totalPages");
+                SetString(isolate, remainingPages, "remainingPages");
+
+                SetCode(isolate, SQLITE_OK, "SQLITE_OK");
+                SetCode(isolate, SQLITE_ERROR, "SQLITE_ERROR");
+                SetCode(isolate, SQLITE_INTERNAL, "SQLITE_INTERNAL");
+                SetCode(isolate, SQLITE_PERM, "SQLITE_PERM");
+                SetCode(isolate, SQLITE_ABORT, "SQLITE_ABORT");
+                SetCode(isolate, SQLITE_BUSY, "SQLITE_BUSY");
+                SetCode(isolate, SQLITE_LOCKED, "SQLITE_LOCKED");
+                SetCode(isolate, SQLITE_NOMEM, "SQLITE_NOMEM");
+                SetCode(isolate, SQLITE_READONLY, "SQLITE_READONLY");
+                SetCode(isolate, SQLITE_INTERRUPT, "SQLITE_INTERRUPT");
+                SetCode(isolate, SQLITE_IOERR, "SQLITE_IOERR");
+                SetCode(isolate, SQLITE_CORRUPT, "SQLITE_CORRUPT");
+                SetCode(isolate, SQLITE_NOTFOUND, "SQLITE_NOTFOUND");
+                SetCode(isolate, SQLITE_FULL, "SQLITE_FULL");
+                SetCode(isolate, SQLITE_CANTOPEN, "SQLITE_CANTOPEN");
+                SetCode(isolate, SQLITE_PROTOCOL, "SQLITE_PROTOCOL");
+                SetCode(isolate, SQLITE_EMPTY, "SQLITE_EMPTY");
+                SetCode(isolate, SQLITE_SCHEMA, "SQLITE_SCHEMA");
+                SetCode(isolate, SQLITE_TOOBIG, "SQLITE_TOOBIG");
+                SetCode(isolate, SQLITE_CONSTRAINT, "SQLITE_CONSTRAINT");
+                SetCode(isolate, SQLITE_MISMATCH, "SQLITE_MISMATCH");
+                SetCode(isolate, SQLITE_MISUSE, "SQLITE_MISUSE");
+                SetCode(isolate, SQLITE_NOLFS, "SQLITE_NOLFS");
+                SetCode(isolate, SQLITE_AUTH, "SQLITE_AUTH");
+                SetCode(isolate, SQLITE_FORMAT, "SQLITE_FORMAT");
+                SetCode(isolate, SQLITE_RANGE, "SQLITE_RANGE");
+                SetCode(isolate, SQLITE_NOTADB, "SQLITE_NOTADB");
+                SetCode(isolate, SQLITE_NOTICE, "SQLITE_NOTICE");
+                SetCode(isolate, SQLITE_WARNING, "SQLITE_WARNING");
+                SetCode(isolate, SQLITE_ROW, "SQLITE_ROW");
+                SetCode(isolate, SQLITE_DONE, "SQLITE_DONE");
+
+                SetCode(isolate, SQLITE_ERROR_MISSING_COLLSEQ, "SQLITE_ERROR_MISSING_COLLSEQ");
+                SetCode(isolate, SQLITE_ERROR_RETRY, "SQLITE_ERROR_RETRY");
+                SetCode(isolate, SQLITE_ERROR_SNAPSHOT, "SQLITE_ERROR_SNAPSHOT");
+                SetCode(isolate, SQLITE_IOERR_READ, "SQLITE_IOERR_READ");
+                SetCode(isolate, SQLITE_IOERR_SHORT_READ, "SQLITE_IOERR_SHORT_READ");
+                SetCode(isolate, SQLITE_IOERR_WRITE, "SQLITE_IOERR_WRITE");
+                SetCode(isolate, SQLITE_IOERR_FSYNC, "SQLITE_IOERR_FSYNC");
+                SetCode(isolate, SQLITE_IOERR_DIR_FSYNC, "SQLITE_IOERR_DIR_FSYNC");
+                SetCode(isolate, SQLITE_IOERR_TRUNCATE, "SQLITE_IOERR_TRUNCATE");
+                SetCode(isolate, SQLITE_IOERR_FSTAT, "SQLITE_IOERR_FSTAT");
+                SetCode(isolate, SQLITE_IOERR_UNLOCK, "SQLITE_IOERR_UNLOCK");
+                SetCode(isolate, SQLITE_IOERR_RDLOCK, "SQLITE_IOERR_RDLOCK");
+                SetCode(isolate, SQLITE_IOERR_DELETE, "SQLITE_IOERR_DELETE");
+                SetCode(isolate, SQLITE_IOERR_BLOCKED, "SQLITE_IOERR_BLOCKED");
+                SetCode(isolate, SQLITE_IOERR_NOMEM, "SQLITE_IOERR_NOMEM");
+                SetCode(isolate, SQLITE_IOERR_ACCESS, "SQLITE_IOERR_ACCESS");
+                SetCode(isolate, SQLITE_IOERR_CHECKRESERVEDLOCK, "SQLITE_IOERR_CHECKRESERVEDLOCK");
+                SetCode(isolate, SQLITE_IOERR_LOCK, "SQLITE_IOERR_LOCK");
+                SetCode(isolate, SQLITE_IOERR_CLOSE, "SQLITE_IOERR_CLOSE");
+                SetCode(isolate, SQLITE_IOERR_DIR_CLOSE, "SQLITE_IOERR_DIR_CLOSE");
+                SetCode(isolate, SQLITE_IOERR_SHMOPEN, "SQLITE_IOERR_SHMOPEN");
+                SetCode(isolate, SQLITE_IOERR_SHMSIZE, "SQLITE_IOERR_SHMSIZE");
+                SetCode(isolate, SQLITE_IOERR_SHMLOCK, "SQLITE_IOERR_SHMLOCK");
+                SetCode(isolate, SQLITE_IOERR_SHMMAP, "SQLITE_IOERR_SHMMAP");
+                SetCode(isolate, SQLITE_IOERR_SEEK, "SQLITE_IOERR_SEEK");
+                SetCode(isolate, SQLITE_IOERR_DELETE_NOENT, "SQLITE_IOERR_DELETE_NOENT");
+                SetCode(isolate, SQLITE_IOERR_MMAP, "SQLITE_IOERR_MMAP");
+                SetCode(isolate, SQLITE_IOERR_GETTEMPPATH, "SQLITE_IOERR_GETTEMPPATH");
+                SetCode(isolate, SQLITE_IOERR_CONVPATH, "SQLITE_IOERR_CONVPATH");
+                SetCode(isolate, SQLITE_IOERR_VNODE, "SQLITE_IOERR_VNODE");
+                SetCode(isolate, SQLITE_IOERR_AUTH, "SQLITE_IOERR_AUTH");
+                SetCode(isolate, SQLITE_IOERR_BEGIN_ATOMIC, "SQLITE_IOERR_BEGIN_ATOMIC");
+                SetCode(isolate, SQLITE_IOERR_COMMIT_ATOMIC, "SQLITE_IOERR_COMMIT_ATOMIC");
+                SetCode(isolate, SQLITE_IOERR_ROLLBACK_ATOMIC, "SQLITE_IOERR_ROLLBACK_ATOMIC");
+                SetCode(isolate, SQLITE_IOERR_DATA, "SQLITE_IOERR_DATA");
+                SetCode(isolate, SQLITE_IOERR_CORRUPTFS, "SQLITE_IOERR_CORRUPTFS");
+                SetCode(isolate, SQLITE_IOERR_IN_PAGE, "SQLITE_IOERR_IN_PAGE");
+                SetCode(isolate, SQLITE_LOCKED_SHAREDCACHE, "SQLITE_LOCKED_SHAREDCACHE");
+                SetCode(isolate, SQLITE_LOCKED_VTAB, "SQLITE_LOCKED_VTAB");
+                SetCode(isolate, SQLITE_BUSY_RECOVERY, "SQLITE_BUSY_RECOVERY");
+                SetCode(isolate, SQLITE_BUSY_SNAPSHOT, "SQLITE_BUSY_SNAPSHOT");
+                SetCode(isolate, SQLITE_CANTOPEN_NOTEMPDIR, "SQLITE_CANTOPEN_NOTEMPDIR");
+                SetCode(isolate, SQLITE_CANTOPEN_ISDIR, "SQLITE_CANTOPEN_ISDIR");
+                SetCode(isolate, SQLITE_CANTOPEN_FULLPATH, "SQLITE_CANTOPEN_FULLPATH");
+                SetCode(isolate, SQLITE_CANTOPEN_CONVPATH, "SQLITE_CANTOPEN_CONVPATH");
+                SetCode(isolate, SQLITE_CANTOPEN_DIRTYWAL, "SQLITE_CANTOPEN_DIRTYWAL");
+                SetCode(isolate, SQLITE_CANTOPEN_SYMLINK, "SQLITE_CANTOPEN_SYMLINK");
+                SetCode(isolate, SQLITE_CORRUPT_VTAB, "SQLITE_CORRUPT_VTAB");
+                SetCode(isolate, SQLITE_CORRUPT_SEQUENCE, "SQLITE_CORRUPT_SEQUENCE");
+                SetCode(isolate, SQLITE_CORRUPT_INDEX, "SQLITE_CORRUPT_INDEX");
+                SetCode(isolate, SQLITE_READONLY_RECOVERY, "SQLITE_READONLY_RECOVERY");
+                SetCode(isolate, SQLITE_READONLY_CANTLOCK, "SQLITE_READONLY_CANTLOCK");
+                SetCode(isolate, SQLITE_READONLY_ROLLBACK, "SQLITE_READONLY_ROLLBACK");
+                SetCode(isolate, SQLITE_READONLY_DBMOVED, "SQLITE_READONLY_DBMOVED");
+                SetCode(isolate, SQLITE_READONLY_CANTINIT, "SQLITE_READONLY_CANTINIT");
+                SetCode(isolate, SQLITE_READONLY_DIRECTORY, "SQLITE_READONLY_DIRECTORY");
+                SetCode(isolate, SQLITE_ABORT_ROLLBACK, "SQLITE_ABORT_ROLLBACK");
+                SetCode(isolate, SQLITE_CONSTRAINT_CHECK, "SQLITE_CONSTRAINT_CHECK");
+                SetCode(isolate, SQLITE_CONSTRAINT_COMMITHOOK, "SQLITE_CONSTRAINT_COMMITHOOK");
+                SetCode(isolate, SQLITE_CONSTRAINT_FOREIGNKEY, "SQLITE_CONSTRAINT_FOREIGNKEY");
+                SetCode(isolate, SQLITE_CONSTRAINT_FUNCTION, "SQLITE_CONSTRAINT_FUNCTION");
+                SetCode(isolate, SQLITE_CONSTRAINT_NOTNULL, "SQLITE_CONSTRAINT_NOTNULL");
+                SetCode(isolate, SQLITE_CONSTRAINT_PRIMARYKEY, "SQLITE_CONSTRAINT_PRIMARYKEY");
+                SetCode(isolate, SQLITE_CONSTRAINT_TRIGGER, "SQLITE_CONSTRAINT_TRIGGER");
+                SetCode(isolate, SQLITE_CONSTRAINT_UNIQUE, "SQLITE_CONSTRAINT_UNIQUE");
+                SetCode(isolate, SQLITE_CONSTRAINT_VTAB, "SQLITE_CONSTRAINT_VTAB");
+                SetCode(isolate, SQLITE_CONSTRAINT_ROWID, "SQLITE_CONSTRAINT_ROWID");
+                SetCode(isolate, SQLITE_CONSTRAINT_PINNED, "SQLITE_CONSTRAINT_PINNED");
+                SetCode(isolate, SQLITE_CONSTRAINT_DATATYPE, "SQLITE_CONSTRAINT_DATATYPE");
+                SetCode(isolate, SQLITE_NOTICE_RECOVER_WAL, "SQLITE_NOTICE_RECOVER_WAL");
+                SetCode(isolate, SQLITE_NOTICE_RECOVER_ROLLBACK, "SQLITE_NOTICE_RECOVER_ROLLBACK");
+                SetCode(isolate, SQLITE_NOTICE_RBU, "SQLITE_NOTICE_RBU");
+                SetCode(isolate, SQLITE_WARNING_AUTOINDEX, "SQLITE_WARNING_AUTOINDEX");
+                SetCode(isolate, SQLITE_AUTH_USER, "SQLITE_AUTH_USER");
+                SetCode(isolate, SQLITE_OK_LOAD_PERMANENTLY, "SQLITE_OK_LOAD_PERMANENTLY");
+                SetCode(isolate, SQLITE_OK_SYMLINK, "SQLITE_OK_SYMLINK");
+}
+#line 161 "./src/util/constants.lzz"
+void CS::SetString (v8::Isolate * isolate, v8::Global <v8::String> & constant, char const * str)
+#line 161 "./src/util/constants.lzz"
+                                                                                                       {
+                constant.Reset(isolate, InternalizedFromLatin1(isolate, str));
+}
+#line 165 "./src/util/constants.lzz"
+void CS::SetCode (v8::Isolate * isolate, int code, char const * str)
+#line 165 "./src/util/constants.lzz"
+                                                                      {
+                codes.emplace(std::piecewise_construct,
+                        std::forward_as_tuple(code),
+                        std::forward_as_tuple(isolate, InternalizedFromLatin1(isolate, str)));
+}
+#line 19 "./src/util/bind-map.lzz"
+BindMap::Pair::Pair (v8::Isolate * isolate, char const * name, int index)
+#line 20 "./src/util/bind-map.lzz"
+  : name (isolate, InternalizedFromUtf8(isolate, name, -1)), index (index)
+#line 20 "./src/util/bind-map.lzz"
+                                                                                                       {}
+#line 22 "./src/util/bind-map.lzz"
+BindMap::Pair::Pair (v8::Isolate * isolate, Pair * pair)
+#line 23 "./src/util/bind-map.lzz"
+  : name (isolate, pair->name), index (pair->index)
+#line 23 "./src/util/bind-map.lzz"
+                                                                                {}
+#line 29 "./src/util/bind-map.lzz"
+BindMap::BindMap (char _)
+#line 29 "./src/util/bind-map.lzz"
+                                 {
+                assert(_ == 0);
+                pairs = NULL;
+                capacity = 0;
+                length = 0;
+}
+#line 36 "./src/util/bind-map.lzz"
+BindMap::~ BindMap ()
+#line 36 "./src/util/bind-map.lzz"
+                   {
+                while (length) pairs[--length].~Pair();
+                FREE_ARRAY<Pair>(pairs);
+}
+#line 50 "./src/util/bind-map.lzz"
+void BindMap::Add (v8::Isolate * isolate, char const * name, int index)
+#line 50 "./src/util/bind-map.lzz"
+                                                                    {
+                assert(name != NULL);
+                if (capacity == length) Grow(isolate);
+                new (pairs + length++) Pair(isolate, name, index);
+}
+#line 58 "./src/util/bind-map.lzz"
+void BindMap::Grow (v8::Isolate * isolate)
+#line 58 "./src/util/bind-map.lzz"
+                                        {
+                assert(capacity == length);
+                capacity = (capacity << 1) | 2;
+                Pair* new_pairs = ALLOC_ARRAY<Pair>(capacity);
+                for (int i = 0; i < length; ++i) {
+                        new (new_pairs + i) Pair(isolate, pairs + i);
+                        pairs[i].~Pair();
+                }
+                FREE_ARRAY<Pair>(pairs);
+                pairs = new_pairs;
+}
+#line 4 "./src/objects/database.lzz"
+v8::Local <v8 :: Function> Database::Init (v8::Isolate * isolate, v8::Local <v8 :: External> data)
+#line 4 "./src/objects/database.lzz"
+                   {
+                v8::Local<v8::FunctionTemplate> t = NewConstructorTemplate(isolate, data, JS_new, "Database");
+                SetPrototypeMethod(isolate, data, t, "prepare", JS_prepare);
+                SetPrototypeMethod(isolate, data, t, "exec", JS_exec);
+                SetPrototypeMethod(isolate, data, t, "backup", JS_backup);
+                SetPrototypeMethod(isolate, data, t, "serialize", JS_serialize);
+                SetPrototypeMethod(isolate, data, t, "function", JS_function);
+                SetPrototypeMethod(isolate, data, t, "aggregate", JS_aggregate);
+                SetPrototypeMethod(isolate, data, t, "table", JS_table);
+                SetPrototypeMethod(isolate, data, t, "loadExtension", JS_loadExtension);
+                SetPrototypeMethod(isolate, data, t, "close", JS_close);
+                SetPrototypeMethod(isolate, data, t, "defaultSafeIntegers", JS_defaultSafeIntegers);
+                SetPrototypeMethod(isolate, data, t, "unsafeMode", JS_unsafeMode);
+                SetPrototypeGetter(isolate, data, t, "open", JS_open);
+                SetPrototypeGetter(isolate, data, t, "inTransaction", JS_inTransaction);
+                return t->GetFunction( isolate -> GetCurrentContext ( ) ).ToLocalChecked();
+}
+#line 24 "./src/objects/database.lzz"
+bool Database::CompareDatabase::operator () (Database const * const a, Database const * const b) const
+#line 24 "./src/objects/database.lzz"
+                                                                                           {
+                        return a < b;
+}
+#line 29 "./src/objects/database.lzz"
+bool Database::CompareStatement::operator () (Statement const * const a, Statement const * const b) const
+#line 29 "./src/objects/database.lzz"
+                                                                                             {
+                        return Statement::Compare(a, b);
+}
+#line 34 "./src/objects/database.lzz"
+bool Database::CompareBackup::operator () (Backup const * const a, Backup const * const b) const
+#line 34 "./src/objects/database.lzz"
+                                                                                       {
+                        return Backup::Compare(a, b);
+}
+#line 40 "./src/objects/database.lzz"
+void Database::ThrowDatabaseError ()
+#line 40 "./src/objects/database.lzz"
+                                  {
+                if (was_js_error) was_js_error = false;
+                else ThrowSqliteError(addon, db_handle);
+}
+#line 44 "./src/objects/database.lzz"
+void Database::ThrowSqliteError (Addon * addon, sqlite3 * db_handle)
+#line 44 "./src/objects/database.lzz"
+                                                                       {
+                assert(db_handle != NULL);
+                ThrowSqliteError(addon, sqlite3_errmsg(db_handle), sqlite3_extended_errcode(db_handle));
+}
+#line 48 "./src/objects/database.lzz"
+void Database::ThrowSqliteError (Addon * addon, char const * message, int code)
+#line 48 "./src/objects/database.lzz"
+                                                                                  {
+                assert(message != NULL);
+                assert((code & 0xff) != SQLITE_OK);
+                assert((code & 0xff) != SQLITE_ROW);
+                assert((code & 0xff) != SQLITE_DONE);
+                v8 :: Isolate * isolate = v8 :: Isolate :: GetCurrent ( ) ;
+                v8::Local<v8::Value> args[2] = {
+                        StringFromUtf8(isolate, message, -1),
+                        addon->cs.Code(isolate, code)
+                };
+                isolate->ThrowException(addon->SqliteError.Get(isolate)
+                        ->NewInstance( isolate -> GetCurrentContext ( ) , 2, args)
+                        .ToLocalChecked());
+}
+#line 64 "./src/objects/database.lzz"
+bool Database::Log (v8::Isolate * isolate, sqlite3_stmt * handle)
+#line 64 "./src/objects/database.lzz"
+                                                             {
+                assert(was_js_error == false);
+                if (!has_logger) return false;
+                char* expanded = sqlite3_expanded_sql(handle);
+                v8::Local<v8::Value> arg = StringFromUtf8(isolate, expanded ? expanded : sqlite3_sql(handle), -1);
+                was_js_error = logger.Get(isolate).As<v8::Function>()
+                        ->Call( isolate -> GetCurrentContext ( ) , v8::Undefined(isolate), 1, &arg)
+                        .IsEmpty();
+                if (expanded) sqlite3_free(expanded);
+                return was_js_error;
+}
+#line 107 "./src/objects/database.lzz"
+void Database::CloseHandles ()
+#line 107 "./src/objects/database.lzz"
+                            {
+                if (open) {
+                        open = false;
+                        for (Statement* stmt : stmts) stmt->CloseHandles();
+                        for (Backup* backup : backups) backup->CloseHandles();
+                        stmts.clear();
+                        backups.clear();
+                        int status = sqlite3_close(db_handle);
+                        assert(status == SQLITE_OK); ((void)status);
+                }
+}
+#line 119 "./src/objects/database.lzz"
+Database::~ Database ()
+#line 119 "./src/objects/database.lzz"
+                    {
+                if (open) addon->dbs.erase(this);
+                CloseHandles();
+}
+#line 126 "./src/objects/database.lzz"
+Database::Database (v8::Isolate * isolate, Addon * addon, sqlite3 * db_handle, v8::Local <v8::Value> logger)
+#line 131 "./src/objects/database.lzz"
+  : node::ObjectWrap (), db_handle (db_handle), open (true), busy (false), safe_ints (false), unsafe_mode (false), was_js_error (false), has_logger (logger->IsFunction()), iterators (0), addon (addon), logger (isolate, logger), stmts (), backups ()
+#line 144 "./src/objects/database.lzz"
+                          {
+                assert(db_handle != NULL);
+                addon->dbs.insert(this);
+}
+#line 149 "./src/objects/database.lzz"
+void Database::JS_new (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 149 "./src/objects/database.lzz"
+                            {
+                assert(info.IsConstructCall());
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > filename = ( info [ 0 ] . As < v8 :: String > ( ) ) ;
+                if ( info . Length ( ) <= ( 1 ) || ! info [ 1 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "second" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > filenameGiven = ( info [ 1 ] . As < v8 :: String > ( ) ) ;
+                if ( info . Length ( ) <= ( 2 ) || ! info [ 2 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "third" " argument to be " "a boolean" ) ; bool in_memory = ( info [ 2 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 3 ) || ! info [ 3 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "fourth" " argument to be " "a boolean" ) ; bool readonly = ( info [ 3 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 4 ) || ! info [ 4 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "fifth" " argument to be " "a boolean" ) ; bool must_exist = ( info [ 4 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 5 ) || ! info [ 5 ] -> IsInt32 ( ) ) return ThrowTypeError ( "Expected " "sixth" " argument to be " "a 32-bit signed integer" ) ; int timeout = ( info [ 5 ] . As < v8 :: Int32 > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 6 ) ) return ThrowTypeError ( "Expected a " "seventh" " argument" ) ; v8 :: Local < v8 :: Value > logger = info [ 6 ] ;
+                if ( info . Length ( ) <= ( 7 ) ) return ThrowTypeError ( "Expected a " "eighth" " argument" ) ; v8 :: Local < v8 :: Value > buffer = info [ 7 ] ;
+
+                Addon * addon = static_cast < Addon * > ( info . Data ( ) . As < v8 :: External > ( ) -> Value ( ) ) ;
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                sqlite3* db_handle;
+                v8::String::Utf8Value utf8(isolate, filename);
+                int mask = readonly ? SQLITE_OPEN_READONLY
+                        : must_exist ? SQLITE_OPEN_READWRITE
+                        : (SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE);
+
+                if (sqlite3_open_v2(*utf8, &db_handle, mask, NULL) != SQLITE_OK) {
+                        ThrowSqliteError(addon, db_handle);
+                        int status = sqlite3_close(db_handle);
+                        assert(status == SQLITE_OK); ((void)status);
+                        return;
+                }
+
+                assert(sqlite3_db_mutex(db_handle) == NULL);
+                sqlite3_extended_result_codes(db_handle, 1);
+                sqlite3_busy_timeout(db_handle, timeout);
+                sqlite3_limit(db_handle, SQLITE_LIMIT_LENGTH, MAX_BUFFER_SIZE < MAX_STRING_SIZE ? MAX_BUFFER_SIZE : MAX_STRING_SIZE);
+                sqlite3_limit(db_handle, SQLITE_LIMIT_SQL_LENGTH, MAX_STRING_SIZE);
+                int status = sqlite3_db_config(db_handle, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, NULL);
+                assert(status == SQLITE_OK);
+                status = sqlite3_db_config(db_handle, SQLITE_DBCONFIG_DEFENSIVE, 1, NULL);
+                assert(status == SQLITE_OK);
+
+                if (node::Buffer::HasInstance(buffer) && !Deserialize(buffer.As<v8::Object>(), addon, db_handle, readonly)) {
+                        int status = sqlite3_close(db_handle);
+                        assert(status == SQLITE_OK); ((void)status);
+                        return;
+                }
+
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+                Database* db = new Database(isolate, addon, db_handle, logger);
+                db->Wrap(info.This());
+                SetFrozen(isolate, ctx, info.This(), addon->cs.memory, v8::Boolean::New(isolate, in_memory));
+                SetFrozen(isolate, ctx, info.This(), addon->cs.readonly, v8::Boolean::New(isolate, readonly));
+                SetFrozen(isolate, ctx, info.This(), addon->cs.name, filenameGiven);
+
+                info.GetReturnValue().Set(info.This());
+}
+#line 201 "./src/objects/database.lzz"
+void Database::JS_prepare (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 201 "./src/objects/database.lzz"
+                                {
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > source = ( info [ 0 ] . As < v8 :: String > ( ) ) ;
+                if ( info . Length ( ) <= ( 1 ) || ! info [ 1 ] -> IsObject ( ) ) return ThrowTypeError ( "Expected " "second" " argument to be " "an object" ) ; v8 :: Local < v8 :: Object > database = ( info [ 1 ] . As < v8 :: Object > ( ) ) ;
+                if ( info . Length ( ) <= ( 2 ) || ! info [ 2 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "third" " argument to be " "a boolean" ) ; bool pragmaMode = ( info [ 2 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                (void)source;
+                (void)database;
+                (void)pragmaMode;
+                Addon * addon = static_cast < Addon * > ( info . Data ( ) . As < v8 :: External > ( ) -> Value ( ) ) ;
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8::Local<v8::Function> c = addon->Statement.Get(isolate);
+                addon->privileged_info = &info;
+                v8::MaybeLocal<v8::Object> maybeStatement = c->NewInstance( isolate -> GetCurrentContext ( ) , 0, NULL);
+                addon->privileged_info = NULL;
+                if (!maybeStatement.IsEmpty()) info.GetReturnValue().Set(maybeStatement.ToLocalChecked());
+}
+#line 217 "./src/objects/database.lzz"
+void Database::JS_exec (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 217 "./src/objects/database.lzz"
+                             {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > source = ( info [ 0 ] . As < v8 :: String > ( ) ) ;
+                if ( ! db -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( db -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( ! db -> unsafe_mode ) { if ( db -> iterators ) return ThrowTypeError ( "This database connection is busy executing a query" ) ; } ( ( void ) 0 ) ;
+                db->busy = true;
+
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8::String::Utf8Value utf8(isolate, source);
+                const char* sql = *utf8;
+                const char* tail;
+
+                int status;
+                const bool has_logger = db->has_logger;
+                sqlite3* const db_handle = db->db_handle;
+                sqlite3_stmt* handle;
+
+                for (;;) {
+                        while (IS_SKIPPED(*sql)) ++sql;
+                        status = sqlite3_prepare_v2(db_handle, sql, -1, &handle, &tail);
+                        sql = tail;
+                        if (!handle) break;
+                        if (has_logger && db->Log(isolate, handle)) {
+                                sqlite3_finalize(handle);
+                                status = -1;
+                                break;
+                        }
+                        do status = sqlite3_step(handle);
+                        while (status == SQLITE_ROW);
+                        status = sqlite3_finalize(handle);
+                        if (status != SQLITE_OK) break;
+                }
+
+                db->busy = false;
+                if (status != SQLITE_OK) {
+                        db->ThrowDatabaseError();
+                }
+}
+#line 257 "./src/objects/database.lzz"
+void Database::JS_backup (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 257 "./src/objects/database.lzz"
+                               {
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsObject ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "an object" ) ; v8 :: Local < v8 :: Object > database = ( info [ 0 ] . As < v8 :: Object > ( ) ) ;
+                if ( info . Length ( ) <= ( 1 ) || ! info [ 1 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "second" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > attachedName = ( info [ 1 ] . As < v8 :: String > ( ) ) ;
+                if ( info . Length ( ) <= ( 2 ) || ! info [ 2 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "third" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > destFile = ( info [ 2 ] . As < v8 :: String > ( ) ) ;
+                if ( info . Length ( ) <= ( 3 ) || ! info [ 3 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "fourth" " argument to be " "a boolean" ) ; bool unlink = ( info [ 3 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                (void)database;
+                (void)attachedName;
+                (void)destFile;
+                (void)unlink;
+                Addon * addon = static_cast < Addon * > ( info . Data ( ) . As < v8 :: External > ( ) -> Value ( ) ) ;
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8::Local<v8::Function> c = addon->Backup.Get(isolate);
+                addon->privileged_info = &info;
+                v8::MaybeLocal<v8::Object> maybeBackup = c->NewInstance( isolate -> GetCurrentContext ( ) , 0, NULL);
+                addon->privileged_info = NULL;
+                if (!maybeBackup.IsEmpty()) info.GetReturnValue().Set(maybeBackup.ToLocalChecked());
+}
+#line 275 "./src/objects/database.lzz"
+void Database::JS_serialize (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 275 "./src/objects/database.lzz"
+                                  {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > attachedName = ( info [ 0 ] . As < v8 :: String > ( ) ) ;
+                if ( ! db -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( db -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( db -> iterators ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8::String::Utf8Value attached_name(isolate, attachedName);
+                sqlite3_int64 length = -1;
+                unsigned char* data = sqlite3_serialize(db->db_handle, *attached_name, &length, 0);
+
+                if (!data && length) {
+                        ThrowError("Out of memory");
+                        return;
+                }
+
+                info.GetReturnValue().Set(
+                        SAFE_NEW_BUFFER(isolate, reinterpret_cast<char*>(data), length, FreeSerialization, NULL).ToLocalChecked()
+                );
+}
+#line 297 "./src/objects/database.lzz"
+void Database::JS_function (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 297 "./src/objects/database.lzz"
+                                 {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsFunction ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a function" ) ; v8 :: Local < v8 :: Function > fn = ( info [ 0 ] . As < v8 :: Function > ( ) ) ;
+                if ( info . Length ( ) <= ( 1 ) || ! info [ 1 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "second" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > nameString = ( info [ 1 ] . As < v8 :: String > ( ) ) ;
+                if ( info . Length ( ) <= ( 2 ) || ! info [ 2 ] -> IsInt32 ( ) ) return ThrowTypeError ( "Expected " "third" " argument to be " "a 32-bit signed integer" ) ; int argc = ( info [ 2 ] . As < v8 :: Int32 > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 3 ) || ! info [ 3 ] -> IsInt32 ( ) ) return ThrowTypeError ( "Expected " "fourth" " argument to be " "a 32-bit signed integer" ) ; int safe_ints = ( info [ 3 ] . As < v8 :: Int32 > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 4 ) || ! info [ 4 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "fifth" " argument to be " "a boolean" ) ; bool deterministic = ( info [ 4 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 5 ) || ! info [ 5 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "sixth" " argument to be " "a boolean" ) ; bool direct_only = ( info [ 5 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                if ( ! db -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( db -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( db -> iterators ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8::String::Utf8Value name(isolate, nameString);
+                int mask = SQLITE_UTF8;
+                if (deterministic) mask |= SQLITE_DETERMINISTIC;
+                if (direct_only) mask |= SQLITE_DIRECTONLY;
+                safe_ints = safe_ints < 2 ? safe_ints : static_cast<int>(db->safe_ints);
+
+                if (sqlite3_create_function_v2(db->db_handle, *name, argc, mask, new CustomFunction(isolate, db, *name, fn, safe_ints), CustomFunction::xFunc, NULL, NULL, CustomFunction::xDestroy) != SQLITE_OK) {
+                        db->ThrowDatabaseError();
+                }
+}
+#line 321 "./src/objects/database.lzz"
+void Database::JS_aggregate (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 321 "./src/objects/database.lzz"
+                                  {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                if ( info . Length ( ) <= ( 0 ) ) return ThrowTypeError ( "Expected a " "first" " argument" ) ; v8 :: Local < v8 :: Value > start = info [ 0 ] ;
+                if ( info . Length ( ) <= ( 1 ) || ! info [ 1 ] -> IsFunction ( ) ) return ThrowTypeError ( "Expected " "second" " argument to be " "a function" ) ; v8 :: Local < v8 :: Function > step = ( info [ 1 ] . As < v8 :: Function > ( ) ) ;
+                if ( info . Length ( ) <= ( 2 ) ) return ThrowTypeError ( "Expected a " "third" " argument" ) ; v8 :: Local < v8 :: Value > inverse = info [ 2 ] ;
+                if ( info . Length ( ) <= ( 3 ) ) return ThrowTypeError ( "Expected a " "fourth" " argument" ) ; v8 :: Local < v8 :: Value > result = info [ 3 ] ;
+                if ( info . Length ( ) <= ( 4 ) || ! info [ 4 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "fifth" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > nameString = ( info [ 4 ] . As < v8 :: String > ( ) ) ;
+                if ( info . Length ( ) <= ( 5 ) || ! info [ 5 ] -> IsInt32 ( ) ) return ThrowTypeError ( "Expected " "sixth" " argument to be " "a 32-bit signed integer" ) ; int argc = ( info [ 5 ] . As < v8 :: Int32 > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 6 ) || ! info [ 6 ] -> IsInt32 ( ) ) return ThrowTypeError ( "Expected " "seventh" " argument to be " "a 32-bit signed integer" ) ; int safe_ints = ( info [ 6 ] . As < v8 :: Int32 > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 7 ) || ! info [ 7 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "eighth" " argument to be " "a boolean" ) ; bool deterministic = ( info [ 7 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                if ( info . Length ( ) <= ( 8 ) || ! info [ 8 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "ninth" " argument to be " "a boolean" ) ; bool direct_only = ( info [ 8 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                if ( ! db -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( db -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( db -> iterators ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8::String::Utf8Value name(isolate, nameString);
+                auto xInverse = inverse->IsFunction() ? CustomAggregate::xInverse : NULL;
+                auto xValue = xInverse ? CustomAggregate::xValue : NULL;
+                int mask = SQLITE_UTF8;
+                if (deterministic) mask |= SQLITE_DETERMINISTIC;
+                if (direct_only) mask |= SQLITE_DIRECTONLY;
+                safe_ints = safe_ints < 2 ? safe_ints : static_cast<int>(db->safe_ints);
+
+                if (sqlite3_create_window_function(db->db_handle, *name, argc, mask, new CustomAggregate(isolate, db, *name, start, step, inverse, result, safe_ints), CustomAggregate::xStep, CustomAggregate::xFinal, xValue, xInverse, CustomAggregate::xDestroy) != SQLITE_OK) {
+                        db->ThrowDatabaseError();
+                }
+}
+#line 350 "./src/objects/database.lzz"
+void Database::JS_table (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 350 "./src/objects/database.lzz"
+                              {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsFunction ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a function" ) ; v8 :: Local < v8 :: Function > factory = ( info [ 0 ] . As < v8 :: Function > ( ) ) ;
+                if ( info . Length ( ) <= ( 1 ) || ! info [ 1 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "second" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > nameString = ( info [ 1 ] . As < v8 :: String > ( ) ) ;
+                if ( info . Length ( ) <= ( 2 ) || ! info [ 2 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "third" " argument to be " "a boolean" ) ; bool eponymous = ( info [ 2 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ;
+                if ( ! db -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( db -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( db -> iterators ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8::String::Utf8Value name(isolate, nameString);
+                sqlite3_module* module = eponymous ? &CustomTable::EPONYMOUS_MODULE : &CustomTable::MODULE;
+
+                db->busy = true;
+                if (sqlite3_create_module_v2(db->db_handle, *name, module, new CustomTable(isolate, db, *name, factory), CustomTable::Destructor) != SQLITE_OK) {
+                        db->ThrowDatabaseError();
+                }
+                db->busy = false;
+}
+#line 370 "./src/objects/database.lzz"
+void Database::JS_loadExtension (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 370 "./src/objects/database.lzz"
+                                      {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                v8::Local<v8::String> entryPoint;
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a string" ) ; v8 :: Local < v8 :: String > filename = ( info [ 0 ] . As < v8 :: String > ( ) ) ;
+                if (info.Length() > 1) { if ( info . Length ( ) <= ( 1 ) || ! info [ 1 ] -> IsString ( ) ) return ThrowTypeError ( "Expected " "second" " argument to be " "a string" ) ; entryPoint = ( info [ 1 ] . As < v8 :: String > ( ) ) ; }
+                if ( ! db -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( db -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( db -> iterators ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                char* error;
+                int status = sqlite3_load_extension(
+                        db->db_handle,
+                        *v8::String::Utf8Value(isolate, filename),
+                        entryPoint.IsEmpty() ? NULL : *v8::String::Utf8Value(isolate, entryPoint),
+                        &error
+                );
+                if (status != SQLITE_OK) {
+                        ThrowSqliteError(db->addon, error, status);
+                }
+                sqlite3_free(error);
+}
+#line 392 "./src/objects/database.lzz"
+void Database::JS_close (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 392 "./src/objects/database.lzz"
+                              {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                if (db->open) {
+                        if ( db -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                        if ( db -> iterators ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                        db->addon->dbs.erase(db);
+                        db->CloseHandles();
+                }
+}
+#line 402 "./src/objects/database.lzz"
+void Database::JS_defaultSafeIntegers (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 402 "./src/objects/database.lzz"
+                                            {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                if (info.Length() == 0) db->safe_ints = true;
+                else { if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a boolean" ) ; db -> safe_ints = ( info [ 0 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ; }
+}
+#line 408 "./src/objects/database.lzz"
+void Database::JS_unsafeMode (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 408 "./src/objects/database.lzz"
+                                   {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                if (info.Length() == 0) db->unsafe_mode = true;
+                else { if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a boolean" ) ; db -> unsafe_mode = ( info [ 0 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ; }
+                sqlite3_db_config(db->db_handle, SQLITE_DBCONFIG_DEFENSIVE, static_cast<int>(!db->unsafe_mode), NULL);
+}
+#line 415 "./src/objects/database.lzz"
+void Database::JS_open (v8::Local <v8 :: Name> _, v8::PropertyCallbackInfo <v8 :: Value> const & info)
+#line 415 "./src/objects/database.lzz"
+                             {
+                info.GetReturnValue().Set( node :: ObjectWrap :: Unwrap <Database>(info.This())->open);
+}
+#line 419 "./src/objects/database.lzz"
+void Database::JS_inTransaction (v8::Local <v8 :: Name> _, v8::PropertyCallbackInfo <v8 :: Value> const & info)
+#line 419 "./src/objects/database.lzz"
+                                      {
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(info.This());
+                info.GetReturnValue().Set(db->open && !static_cast<bool>(sqlite3_get_autocommit(db->db_handle)));
+}
+#line 424 "./src/objects/database.lzz"
+bool Database::Deserialize (v8::Local <v8::Object> buffer, Addon * addon, sqlite3 * db_handle, bool readonly)
+#line 424 "./src/objects/database.lzz"
+                                                                                                               {
+                size_t length = node::Buffer::Length(buffer);
+                unsigned char* data = (unsigned char*)sqlite3_malloc64(length);
+                unsigned int flags = SQLITE_DESERIALIZE_FREEONCLOSE | SQLITE_DESERIALIZE_RESIZEABLE;
+
+                if (readonly) {
+                        flags |= SQLITE_DESERIALIZE_READONLY;
+                }
+                if (length) {
+                        if (!data) {
+                                ThrowError("Out of memory");
+                                return false;
+                        }
+                        memcpy(data, node::Buffer::Data(buffer), length);
+                }
+
+                int status = sqlite3_deserialize(db_handle, "main", data, length, length, flags);
+                if (status != SQLITE_OK) {
+                        ThrowSqliteError(addon, status == SQLITE_ERROR ? "unable to deserialize database" : sqlite3_errstr(status), status);
+                        return false;
+                }
+
+                return true;
+}
+#line 449 "./src/objects/database.lzz"
+void Database::FreeSerialization (char * data, void * _)
+#line 449 "./src/objects/database.lzz"
+                                                           {
+                sqlite3_free(data);
+}
+#line 453 "./src/objects/database.lzz"
+int const Database::MAX_BUFFER_SIZE;
+#line 454 "./src/objects/database.lzz"
+int const Database::MAX_STRING_SIZE;
+#line 4 "./src/objects/statement.lzz"
+v8::Local <v8 :: Function> Statement::Init (v8::Isolate * isolate, v8::Local <v8 :: External> data)
+#line 4 "./src/objects/statement.lzz"
+                   {
+                v8::Local<v8::FunctionTemplate> t = NewConstructorTemplate(isolate, data, JS_new, "Statement");
+                SetPrototypeMethod(isolate, data, t, "run", JS_run);
+                SetPrototypeMethod(isolate, data, t, "get", JS_get);
+                SetPrototypeMethod(isolate, data, t, "all", JS_all);
+                SetPrototypeMethod(isolate, data, t, "iterate", JS_iterate);
+                SetPrototypeMethod(isolate, data, t, "bind", JS_bind);
+                SetPrototypeMethod(isolate, data, t, "pluck", JS_pluck);
+                SetPrototypeMethod(isolate, data, t, "expand", JS_expand);
+                SetPrototypeMethod(isolate, data, t, "raw", JS_raw);
+                SetPrototypeMethod(isolate, data, t, "safeIntegers", JS_safeIntegers);
+                SetPrototypeMethod(isolate, data, t, "columns", JS_columns);
+                SetPrototypeGetter(isolate, data, t, "busy", JS_busy);
+                return t->GetFunction( isolate -> GetCurrentContext ( ) ).ToLocalChecked();
+}
+#line 26 "./src/objects/statement.lzz"
+BindMap * Statement::GetBindMap (v8::Isolate * isolate)
+#line 26 "./src/objects/statement.lzz"
+                                                  {
+                if (has_bind_map) return &extras->bind_map;
+                BindMap* bind_map = &extras->bind_map;
+                int param_count = sqlite3_bind_parameter_count(handle);
+                for (int i = 1; i <= param_count; ++i) {
+                        const char* name = sqlite3_bind_parameter_name(handle, i);
+                        if (name != NULL) bind_map->Add(isolate, name + 1, i);
+                }
+                has_bind_map = true;
+                return bind_map;
+}
+#line 39 "./src/objects/statement.lzz"
+void Statement::CloseHandles ()
+#line 39 "./src/objects/statement.lzz"
+                            {
+                if (alive) {
+                        alive = false;
+                        sqlite3_finalize(handle);
+                }
+}
+#line 46 "./src/objects/statement.lzz"
+Statement::~ Statement ()
+#line 46 "./src/objects/statement.lzz"
+                     {
+                if (alive) db->RemoveStatement(this);
+                CloseHandles();
+                delete extras;
+}
+#line 56 "./src/objects/statement.lzz"
+Statement::Extras::Extras (sqlite3_uint64 id)
+#line 56 "./src/objects/statement.lzz"
+  : bind_map (0), id (id)
+#line 56 "./src/objects/statement.lzz"
+                                                                         {}
+#line 61 "./src/objects/statement.lzz"
+Statement::Statement (Database * db, sqlite3_stmt * handle, sqlite3_uint64 id, bool returns_data)
+#line 66 "./src/objects/statement.lzz"
+  : node::ObjectWrap (), db (db), handle (handle), extras (new Extras(id)), alive (true), locked (false), bound (false), has_bind_map (false), safe_ints (db->GetState()->safe_ints), mode (Data::FLAT), returns_data (returns_data)
+#line 77 "./src/objects/statement.lzz"
+                                           {
+                assert(db != NULL);
+                assert(handle != NULL);
+                assert(db->GetState()->open);
+                assert(!db->GetState()->busy);
+                db->AddStatement(this);
+}
+#line 85 "./src/objects/statement.lzz"
+void Statement::JS_new (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 85 "./src/objects/statement.lzz"
+                            {
+                Addon * addon = static_cast < Addon * > ( info . Data ( ) . As < v8 :: External > ( ) -> Value ( ) ) ;
+                if (!addon->privileged_info) {
+                        return ThrowTypeError("Statements can only be constructed by the db.prepare() method");
+                }
+                assert(info.IsConstructCall());
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(addon->privileged_info->This());
+                if ( ! db -> GetState ( ) -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+
+                v8::Local<v8::String> source = (*addon->privileged_info)[0].As<v8::String>();
+                v8::Local<v8::Object> database = (*addon->privileged_info)[1].As<v8::Object>();
+                bool pragmaMode = (*addon->privileged_info)[2].As<v8::Boolean>()->Value();
+                int flags = SQLITE_PREPARE_PERSISTENT;
+
+                if (pragmaMode) {
+                        if ( ! db -> GetState ( ) -> unsafe_mode ) { if ( db -> GetState ( ) -> iterators ) return ThrowTypeError ( "This database connection is busy executing a query" ) ; } ( ( void ) 0 ) ;
+                        flags = 0;
+                }
+
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8::String::Utf8Value utf8(isolate, source);
+                sqlite3_stmt* handle;
+                const char* tail;
+
+                if (sqlite3_prepare_v3(db->GetHandle(), *utf8, utf8.length() + 1, flags, &handle, &tail) != SQLITE_OK) {
+                        return db->ThrowDatabaseError();
+                }
+                if (handle == NULL) {
+                        return ThrowRangeError("The supplied SQL string contains no statements");
+                }
+
+                for (char c; (c = *tail); ) {
+                        if (IS_SKIPPED(c)) {
+                                ++tail;
+                                continue;
+                        }
+                        if (c == '/' && tail[1] == '*') {
+                                tail += 2;
+                                for (char c; (c = *tail); ++tail) {
+                                        if (c == '*' && tail[1] == '/') {
+                                                tail += 2;
+                                                break;
+                                        }
+                                }
+                        } else if (c == '-' && tail[1] == '-') {
+                                tail += 2;
+                                for (char c; (c = *tail); ++tail) {
+                                        if (c == '\n') {
+                                                ++tail;
+                                                break;
+                                        }
+                                }
+                        } else {
+                                sqlite3_finalize(handle);
+                                return ThrowRangeError("The supplied SQL string contains more than one statement");
+                        }
+                }
+
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+                bool returns_data = sqlite3_column_count(handle) >= 1 || pragmaMode;
+                Statement* stmt = new Statement(db, handle, addon->NextId(), returns_data);
+                stmt->Wrap(info.This());
+                SetFrozen(isolate, ctx, info.This(), addon->cs.reader, v8::Boolean::New(isolate, returns_data));
+                SetFrozen(isolate, ctx, info.This(), addon->cs.readonly, v8::Boolean::New(isolate, sqlite3_stmt_readonly(handle) != 0));
+                SetFrozen(isolate, ctx, info.This(), addon->cs.source, source);
+                SetFrozen(isolate, ctx, info.This(), addon->cs.database, database);
+
+                info.GetReturnValue().Set(info.This());
+}
+#line 156 "./src/objects/statement.lzz"
+void Statement::JS_run (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 156 "./src/objects/statement.lzz"
+                            {
+                Statement * stmt = node :: ObjectWrap :: Unwrap < Statement > ( info . This ( ) ) ; ( ( void ) 0 ) ; sqlite3_stmt * handle = stmt -> handle ; Database * db = stmt -> db ; if ( ! db -> GetState ( ) -> open ) return ThrowTypeError ( "The database connection is not open" ) ; if ( db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ; if ( stmt -> locked ) return ThrowTypeError ( "This statement is busy executing a query" ) ; if ( ! db -> GetState ( ) -> unsafe_mode ) { if ( db -> GetState ( ) -> iterators ) return ThrowTypeError ( "This database connection is busy executing a query" ) ; } ( ( void ) 0 ) ; const bool bound = stmt -> bound ; if ( ! bound ) { Binder binder ( handle ) ; if ( ! binder . Bind ( info , info . Length ( ) , stmt ) ) { sqlite3_clear_bindings ( handle ) ; return ; } ( ( void ) 0 ) ; } else if ( info . Length ( ) > 0 ) { return ThrowTypeError ( "This statement already has bound parameters" ) ; } ( ( void ) 0 ) ; db -> GetState ( ) -> busy = true ; v8 :: Isolate * isolate = info . GetIsolate ( ) ; if ( db -> Log ( isolate , handle ) ) { db -> GetState ( ) -> busy = false ; db -> ThrowDatabaseError ( ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ; } ( ( void ) 0 ) ;
+                sqlite3* db_handle = db->GetHandle();
+                int total_changes_before = sqlite3_total_changes(db_handle);
+
+                sqlite3_step(handle);
+                if (sqlite3_reset(handle) == SQLITE_OK) {
+                        int changes = sqlite3_total_changes(db_handle) == total_changes_before ? 0 : sqlite3_changes(db_handle);
+                        sqlite3_int64 id = sqlite3_last_insert_rowid(db_handle);
+                        Addon* addon = db->GetAddon();
+                        v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+                        v8::Local<v8::Object> result = v8::Object::New(isolate);
+                        result->Set(ctx, addon->cs.changes.Get(isolate), v8::Int32::New(isolate, changes)).FromJust();
+                        result->Set(ctx, addon->cs.lastInsertRowid.Get(isolate),
+                                stmt->safe_ints
+                                        ? v8::BigInt::New(isolate, id).As<v8::Value>()
+                                        : v8::Number::New(isolate, (double)id).As<v8::Value>()
+                        ).FromJust();
+                        db -> GetState ( ) -> busy = false ; info . GetReturnValue ( ) . Set ( result ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ;
+                }
+                db -> GetState ( ) -> busy = false ; db -> ThrowDatabaseError ( ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ;
+}
+#line 179 "./src/objects/statement.lzz"
+void Statement::JS_get (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 179 "./src/objects/statement.lzz"
+                            {
+                Statement * stmt = node :: ObjectWrap :: Unwrap < Statement > ( info . This ( ) ) ; if ( ! stmt -> returns_data ) return ThrowTypeError ( "This statement does not return data. Use run() instead" ) ; sqlite3_stmt * handle = stmt -> handle ; Database * db = stmt -> db ; if ( ! db -> GetState ( ) -> open ) return ThrowTypeError ( "The database connection is not open" ) ; if ( db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ; if ( stmt -> locked ) return ThrowTypeError ( "This statement is busy executing a query" ) ; const bool bound = stmt -> bound ; if ( ! bound ) { Binder binder ( handle ) ; if ( ! binder . Bind ( info , info . Length ( ) , stmt ) ) { sqlite3_clear_bindings ( handle ) ; return ; } ( ( void ) 0 ) ; } else if ( info . Length ( ) > 0 ) { return ThrowTypeError ( "This statement already has bound parameters" ) ; } ( ( void ) 0 ) ; db -> GetState ( ) -> busy = true ; v8 :: Isolate * isolate = info . GetIsolate ( ) ; if ( db -> Log ( isolate , handle ) ) { db -> GetState ( ) -> busy = false ; db -> ThrowDatabaseError ( ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ; } ( ( void ) 0 ) ;
+                int status = sqlite3_step(handle);
+                if (status == SQLITE_ROW) {
+                        v8::Local<v8::Value> result = Data::GetRowJS(isolate, isolate -> GetCurrentContext ( ) , handle, stmt->safe_ints, stmt->mode);
+                        sqlite3_reset(handle);
+                        db -> GetState ( ) -> busy = false ; info . GetReturnValue ( ) . Set ( result ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ;
+                } else if (status == SQLITE_DONE) {
+                        sqlite3_reset(handle);
+                        db -> GetState ( ) -> busy = false ; info . GetReturnValue ( ) . Set ( v8 :: Undefined ( isolate ) ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ;
+                }
+                sqlite3_reset(handle);
+                db -> GetState ( ) -> busy = false ; db -> ThrowDatabaseError ( ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ;
+}
+#line 194 "./src/objects/statement.lzz"
+void Statement::JS_all (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 194 "./src/objects/statement.lzz"
+                            {
+                Statement * stmt = node :: ObjectWrap :: Unwrap < Statement > ( info . This ( ) ) ; if ( ! stmt -> returns_data ) return ThrowTypeError ( "This statement does not return data. Use run() instead" ) ; sqlite3_stmt * handle = stmt -> handle ; Database * db = stmt -> db ; if ( ! db -> GetState ( ) -> open ) return ThrowTypeError ( "The database connection is not open" ) ; if ( db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ; if ( stmt -> locked ) return ThrowTypeError ( "This statement is busy executing a query" ) ; const bool bound = stmt -> bound ; if ( ! bound ) { Binder binder ( handle ) ; if ( ! binder . Bind ( info , info . Length ( ) , stmt ) ) { sqlite3_clear_bindings ( handle ) ; return ; } ( ( void ) 0 ) ; } else if ( info . Length ( ) > 0 ) { return ThrowTypeError ( "This statement already has bound parameters" ) ; } ( ( void ) 0 ) ; db -> GetState ( ) -> busy = true ; v8 :: Isolate * isolate = info . GetIsolate ( ) ; if ( db -> Log ( isolate , handle ) ) { db -> GetState ( ) -> busy = false ; db -> ThrowDatabaseError ( ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ; } ( ( void ) 0 ) ;
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+                v8::Local<v8::Array> result = v8::Array::New(isolate, 0);
+                uint32_t row_count = 0;
+                const bool safe_ints = stmt->safe_ints;
+                const char mode = stmt->mode;
+                bool js_error = false;
+
+                while (sqlite3_step(handle) == SQLITE_ROW) {
+                        if (row_count == 0xffffffff) { ThrowRangeError("Array overflow (too many rows returned)"); js_error = true; break; }
+                        result->Set(ctx, row_count++, Data::GetRowJS(isolate, ctx, handle, safe_ints, mode)).FromJust();
+                }
+
+                if (sqlite3_reset(handle) == SQLITE_OK && !js_error) {
+                        db -> GetState ( ) -> busy = false ; info . GetReturnValue ( ) . Set ( result ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ;
+                }
+                if (js_error) db->GetState()->was_js_error = true;
+                db -> GetState ( ) -> busy = false ; db -> ThrowDatabaseError ( ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ;
+}
+#line 215 "./src/objects/statement.lzz"
+void Statement::JS_iterate (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 215 "./src/objects/statement.lzz"
+                                {
+                Addon * addon = static_cast < Addon * > ( info . Data ( ) . As < v8 :: External > ( ) -> Value ( ) ) ;
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8::Local<v8::Function> c = addon->StatementIterator.Get(isolate);
+                addon->privileged_info = &info;
+                v8::MaybeLocal<v8::Object> maybeIterator = c->NewInstance( isolate -> GetCurrentContext ( ) , 0, NULL);
+                addon->privileged_info = NULL;
+                if (!maybeIterator.IsEmpty()) info.GetReturnValue().Set(maybeIterator.ToLocalChecked());
+}
+#line 225 "./src/objects/statement.lzz"
+void Statement::JS_bind (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 225 "./src/objects/statement.lzz"
+                             {
+                Statement* stmt = node :: ObjectWrap :: Unwrap <Statement>(info.This());
+                if (stmt->bound) return ThrowTypeError("The bind() method can only be invoked once per statement object");
+                if ( ! stmt -> db -> GetState ( ) -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( stmt -> db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( stmt -> locked ) return ThrowTypeError ( "This statement is busy executing a query" ) ;
+                Binder binder ( stmt -> handle ) ; if ( ! binder . Bind ( info , info . Length ( ) , stmt ) ) { sqlite3_clear_bindings ( stmt -> handle ) ; return ; } ( ( void ) 0 ) ;
+                stmt->bound = true;
+                info.GetReturnValue().Set(info.This());
+}
+#line 236 "./src/objects/statement.lzz"
+void Statement::JS_pluck (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 236 "./src/objects/statement.lzz"
+                              {
+                Statement* stmt = node :: ObjectWrap :: Unwrap <Statement>(info.This());
+                if (!stmt->returns_data) return ThrowTypeError("The pluck() method is only for statements that return data");
+                if ( stmt -> db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( stmt -> locked ) return ThrowTypeError ( "This statement is busy executing a query" ) ;
+                bool use = true;
+                if (info.Length() != 0) { if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a boolean" ) ; use = ( info [ 0 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ; }
+                stmt->mode = use ? Data::PLUCK : stmt->mode == Data::PLUCK ? Data::FLAT : stmt->mode;
+                info.GetReturnValue().Set(info.This());
+}
+#line 247 "./src/objects/statement.lzz"
+void Statement::JS_expand (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 247 "./src/objects/statement.lzz"
+                               {
+                Statement* stmt = node :: ObjectWrap :: Unwrap <Statement>(info.This());
+                if (!stmt->returns_data) return ThrowTypeError("The expand() method is only for statements that return data");
+                if ( stmt -> db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( stmt -> locked ) return ThrowTypeError ( "This statement is busy executing a query" ) ;
+                bool use = true;
+                if (info.Length() != 0) { if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a boolean" ) ; use = ( info [ 0 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ; }
+                stmt->mode = use ? Data::EXPAND : stmt->mode == Data::EXPAND ? Data::FLAT : stmt->mode;
+                info.GetReturnValue().Set(info.This());
+}
+#line 258 "./src/objects/statement.lzz"
+void Statement::JS_raw (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 258 "./src/objects/statement.lzz"
+                            {
+                Statement* stmt = node :: ObjectWrap :: Unwrap <Statement>(info.This());
+                if (!stmt->returns_data) return ThrowTypeError("The raw() method is only for statements that return data");
+                if ( stmt -> db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( stmt -> locked ) return ThrowTypeError ( "This statement is busy executing a query" ) ;
+                bool use = true;
+                if (info.Length() != 0) { if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a boolean" ) ; use = ( info [ 0 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ; }
+                stmt->mode = use ? Data::RAW : stmt->mode == Data::RAW ? Data::FLAT : stmt->mode;
+                info.GetReturnValue().Set(info.This());
+}
+#line 269 "./src/objects/statement.lzz"
+void Statement::JS_safeIntegers (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 269 "./src/objects/statement.lzz"
+                                     {
+                Statement* stmt = node :: ObjectWrap :: Unwrap <Statement>(info.This());
+                if ( stmt -> db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if ( stmt -> locked ) return ThrowTypeError ( "This statement is busy executing a query" ) ;
+                if (info.Length() == 0) stmt->safe_ints = true;
+                else { if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsBoolean ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a boolean" ) ; stmt -> safe_ints = ( info [ 0 ] . As < v8 :: Boolean > ( ) ) -> Value ( ) ; }
+                info.GetReturnValue().Set(info.This());
+}
+#line 278 "./src/objects/statement.lzz"
+void Statement::JS_columns (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 278 "./src/objects/statement.lzz"
+                                {
+                Statement* stmt = node :: ObjectWrap :: Unwrap <Statement>(info.This());
+                if (!stmt->returns_data) return ThrowTypeError("The columns() method is only for statements that return data");
+                if ( ! stmt -> db -> GetState ( ) -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( stmt -> db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                Addon* addon = stmt->db->GetAddon();
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+
+                int column_count = sqlite3_column_count(stmt->handle);
+                v8::Local<v8::Array> columns = v8::Array::New(isolate);
+
+                v8::Local<v8::String> name = addon->cs.name.Get(isolate);
+                v8::Local<v8::String> columnName = addon->cs.column.Get(isolate);
+                v8::Local<v8::String> tableName = addon->cs.table.Get(isolate);
+                v8::Local<v8::String> databaseName = addon->cs.database.Get(isolate);
+                v8::Local<v8::String> typeName = addon->cs.type.Get(isolate);
+
+                for (int i = 0; i < column_count; ++i) {
+                        v8::Local<v8::Object> column = v8::Object::New(isolate);
+
+                        column->Set(ctx, name,
+                                InternalizedFromUtf8OrNull(isolate, sqlite3_column_name(stmt->handle, i), -1)
+                        ).FromJust();
+                        column->Set(ctx, columnName,
+                                InternalizedFromUtf8OrNull(isolate, sqlite3_column_origin_name(stmt->handle, i), -1)
+                        ).FromJust();
+                        column->Set(ctx, tableName,
+                                InternalizedFromUtf8OrNull(isolate, sqlite3_column_table_name(stmt->handle, i), -1)
+                        ).FromJust();
+                        column->Set(ctx, databaseName,
+                                InternalizedFromUtf8OrNull(isolate, sqlite3_column_database_name(stmt->handle, i), -1)
+                        ).FromJust();
+                        column->Set(ctx, typeName,
+                                InternalizedFromUtf8OrNull(isolate, sqlite3_column_decltype(stmt->handle, i), -1)
+                        ).FromJust();
+
+                        columns->Set(ctx, i, column).FromJust();
+                }
+
+                info.GetReturnValue().Set(columns);
+}
+#line 321 "./src/objects/statement.lzz"
+void Statement::JS_busy (v8::Local <v8 :: Name> _, v8::PropertyCallbackInfo <v8 :: Value> const & info)
+#line 321 "./src/objects/statement.lzz"
+                             {
+                Statement* stmt = node :: ObjectWrap :: Unwrap <Statement>(info.This());
+                info.GetReturnValue().Set(stmt->alive && stmt->locked);
+}
+#line 4 "./src/objects/statement-iterator.lzz"
+v8::Local <v8 :: Function> StatementIterator::Init (v8::Isolate * isolate, v8::Local <v8 :: External> data)
+#line 4 "./src/objects/statement-iterator.lzz"
+                   {
+                v8::Local<v8::FunctionTemplate> t = NewConstructorTemplate(isolate, data, JS_new, "StatementIterator");
+                SetPrototypeMethod(isolate, data, t, "next", JS_next);
+                SetPrototypeMethod(isolate, data, t, "return", JS_return);
+                SetPrototypeSymbolMethod(isolate, data, t, v8::Symbol::GetIterator(isolate), JS_symbolIterator);
+                return t->GetFunction( isolate -> GetCurrentContext ( ) ).ToLocalChecked();
+}
+#line 15 "./src/objects/statement-iterator.lzz"
+StatementIterator::~ StatementIterator ()
+#line 15 "./src/objects/statement-iterator.lzz"
+                             {}
+#line 19 "./src/objects/statement-iterator.lzz"
+StatementIterator::StatementIterator (Statement * stmt, bool bound)
+#line 19 "./src/objects/statement-iterator.lzz"
+  : node::ObjectWrap (), stmt (stmt), handle (stmt->handle), db_state (stmt->db->GetState()), bound (bound), safe_ints (stmt->safe_ints), mode (stmt->mode), alive (true), logged (!db_state->has_logger)
+#line 27 "./src/objects/statement-iterator.lzz"
+                                              {
+                assert(stmt != NULL);
+                assert(handle != NULL);
+                assert(stmt->bound == bound);
+                assert(stmt->alive == true);
+                assert(stmt->locked == false);
+                assert(db_state->iterators < USHRT_MAX);
+                stmt->locked = true;
+                db_state->iterators += 1;
+}
+#line 38 "./src/objects/statement-iterator.lzz"
+void StatementIterator::JS_new (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 38 "./src/objects/statement-iterator.lzz"
+                            {
+                Addon * addon = static_cast < Addon * > ( info . Data ( ) . As < v8 :: External > ( ) -> Value ( ) ) ;
+                if (!addon->privileged_info) return ThrowTypeError("Disabled constructor");
+                assert(info.IsConstructCall());
+
+                StatementIterator* iter;
+                {
+                        const v8 :: FunctionCallbackInfo < v8 :: Value > & info = *addon->privileged_info;
+                        Statement * stmt = node :: ObjectWrap :: Unwrap < Statement > ( info . This ( ) ) ; if ( ! stmt -> returns_data ) return ThrowTypeError ( "This statement does not return data. Use run() instead" ) ; sqlite3_stmt * handle = stmt -> handle ; Database * db = stmt -> db ; if ( ! db -> GetState ( ) -> open ) return ThrowTypeError ( "The database connection is not open" ) ; if ( db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ; if ( stmt -> locked ) return ThrowTypeError ( "This statement is busy executing a query" ) ; if ( db -> GetState ( ) -> iterators == USHRT_MAX ) return ThrowRangeError ( "Too many active database iterators" ) ; const bool bound = stmt -> bound ; if ( ! bound ) { Binder binder ( handle ) ; if ( ! binder . Bind ( info , info . Length ( ) , stmt ) ) { sqlite3_clear_bindings ( handle ) ; return ; } ( ( void ) 0 ) ; } else if ( info . Length ( ) > 0 ) { return ThrowTypeError ( "This statement already has bound parameters" ) ; } ( ( void ) 0 ) ;
+                        iter = new StatementIterator(stmt, bound);
+                }
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+                iter->Wrap(info.This());
+                SetFrozen(isolate, ctx, info.This(), addon->cs.statement, addon->privileged_info->This());
+
+                info.GetReturnValue().Set(info.This());
+}
+#line 57 "./src/objects/statement-iterator.lzz"
+void StatementIterator::JS_next (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 57 "./src/objects/statement-iterator.lzz"
+                             {
+                StatementIterator* iter = node :: ObjectWrap :: Unwrap <StatementIterator>(info.This());
+                if ( iter -> db_state -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if (iter->alive) iter->Next(info);
+                else info.GetReturnValue().Set(DoneRecord( info . GetIsolate ( ) , iter->db_state->addon));
+}
+#line 64 "./src/objects/statement-iterator.lzz"
+void StatementIterator::JS_return (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 64 "./src/objects/statement-iterator.lzz"
+                               {
+                StatementIterator* iter = node :: ObjectWrap :: Unwrap <StatementIterator>(info.This());
+                if ( iter -> db_state -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+                if (iter->alive) iter->Return(info);
+                else info.GetReturnValue().Set(DoneRecord( info . GetIsolate ( ) , iter->db_state->addon));
+}
+#line 71 "./src/objects/statement-iterator.lzz"
+void StatementIterator::JS_symbolIterator (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 71 "./src/objects/statement-iterator.lzz"
+                                       {
+                info.GetReturnValue().Set(info.This());
+}
+#line 75 "./src/objects/statement-iterator.lzz"
+void StatementIterator::Next (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 75 "./src/objects/statement-iterator.lzz"
+                                       {
+                assert(alive == true);
+                db_state->busy = true;
+                if (!logged) {
+                        logged = true;
+                        if (stmt->db->Log( info . GetIsolate ( ) , handle)) {
+                                db_state->busy = false;
+                                Throw();
+                                return;
+                        }
+                }
+                int status = sqlite3_step(handle);
+                db_state->busy = false;
+                if (status == SQLITE_ROW) {
+                        v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                        v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+                        info.GetReturnValue().Set(
+                                NewRecord(isolate, ctx, Data::GetRowJS(isolate, ctx, handle, safe_ints, mode), db_state->addon, false)
+                        );
+                } else {
+                        if (status == SQLITE_DONE) Return(info);
+                        else Throw();
+                }
+}
+#line 100 "./src/objects/statement-iterator.lzz"
+void StatementIterator::Return (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 100 "./src/objects/statement-iterator.lzz"
+                                         {
+                Cleanup();
+                info . GetReturnValue ( ) . Set ( DoneRecord ( info . GetIsolate ( ) , db_state -> addon ) ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ;
+}
+#line 105 "./src/objects/statement-iterator.lzz"
+void StatementIterator::Throw ()
+#line 105 "./src/objects/statement-iterator.lzz"
+                     {
+                Cleanup();
+                Database* db = stmt->db;
+                db -> ThrowDatabaseError ( ) ; if ( ! bound ) { sqlite3_clear_bindings ( handle ) ; } return ;
+}
+#line 111 "./src/objects/statement-iterator.lzz"
+void StatementIterator::Cleanup ()
+#line 111 "./src/objects/statement-iterator.lzz"
+                       {
+                assert(alive == true);
+                alive = false;
+                stmt->locked = false;
+                db_state->iterators -= 1;
+                sqlite3_reset(handle);
+}
+#line 4 "./src/objects/backup.lzz"
+v8::Local <v8 :: Function> Backup::Init (v8::Isolate * isolate, v8::Local <v8 :: External> data)
+#line 4 "./src/objects/backup.lzz"
+                   {
+                v8::Local<v8::FunctionTemplate> t = NewConstructorTemplate(isolate, data, JS_new, "Backup");
+                SetPrototypeMethod(isolate, data, t, "transfer", JS_transfer);
+                SetPrototypeMethod(isolate, data, t, "close", JS_close);
+                return t->GetFunction( isolate -> GetCurrentContext ( ) ).ToLocalChecked();
+}
+#line 17 "./src/objects/backup.lzz"
+void Backup::CloseHandles ()
+#line 17 "./src/objects/backup.lzz"
+                            {
+                if (alive) {
+                        alive = false;
+                        std::string filename(sqlite3_db_filename(dest_handle, "main"));
+                        sqlite3_backup_finish(backup_handle);
+                        int status = sqlite3_close(dest_handle);
+                        assert(status == SQLITE_OK); ((void)status);
+                        if (unlink) remove(filename.c_str());
+                }
+}
+#line 28 "./src/objects/backup.lzz"
+Backup::~ Backup ()
+#line 28 "./src/objects/backup.lzz"
+                  {
+                if (alive) db->RemoveBackup(this);
+                CloseHandles();
+}
+#line 35 "./src/objects/backup.lzz"
+Backup::Backup (Database * db, sqlite3 * dest_handle, sqlite3_backup * backup_handle, sqlite3_uint64 id, bool unlink)
+#line 41 "./src/objects/backup.lzz"
+  : node::ObjectWrap (), db (db), dest_handle (dest_handle), backup_handle (backup_handle), id (id), alive (true), unlink (unlink)
+#line 48 "./src/objects/backup.lzz"
+                               {
+                assert(db != NULL);
+                assert(dest_handle != NULL);
+                assert(backup_handle != NULL);
+                db->AddBackup(this);
+}
+#line 55 "./src/objects/backup.lzz"
+void Backup::JS_new (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 55 "./src/objects/backup.lzz"
+                            {
+                Addon * addon = static_cast < Addon * > ( info . Data ( ) . As < v8 :: External > ( ) -> Value ( ) ) ;
+                if (!addon->privileged_info) return ThrowTypeError("Disabled constructor");
+                assert(info.IsConstructCall());
+                Database* db = node :: ObjectWrap :: Unwrap <Database>(addon->privileged_info->This());
+                if ( ! db -> GetState ( ) -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                if ( db -> GetState ( ) -> busy ) return ThrowTypeError ( "This database connection is busy executing a query" ) ;
+
+                v8::Local<v8::Object> database = (*addon->privileged_info)[0].As<v8::Object>();
+                v8::Local<v8::String> attachedName = (*addon->privileged_info)[1].As<v8::String>();
+                v8::Local<v8::String> destFile = (*addon->privileged_info)[2].As<v8::String>();
+                bool unlink = (*addon->privileged_info)[3].As<v8::Boolean>()->Value();
+
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                sqlite3* dest_handle;
+                v8::String::Utf8Value dest_file(isolate, destFile);
+                v8::String::Utf8Value attached_name(isolate, attachedName);
+                int mask = (SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE);
+
+                if (sqlite3_open_v2(*dest_file, &dest_handle, mask, NULL) != SQLITE_OK) {
+                        Database::ThrowSqliteError(addon, dest_handle);
+                        int status = sqlite3_close(dest_handle);
+                        assert(status == SQLITE_OK); ((void)status);
+                        return;
+                }
+
+                sqlite3_extended_result_codes(dest_handle, 1);
+                sqlite3_limit(dest_handle, SQLITE_LIMIT_LENGTH, INT_MAX);
+                sqlite3_backup* backup_handle = sqlite3_backup_init(dest_handle, "main", db->GetHandle(), *attached_name);
+                if (backup_handle == NULL) {
+                        Database::ThrowSqliteError(addon, dest_handle);
+                        int status = sqlite3_close(dest_handle);
+                        assert(status == SQLITE_OK); ((void)status);
+                        return;
+                }
+
+                Backup* backup = new Backup(db, dest_handle, backup_handle, addon->NextId(), unlink);
+                backup->Wrap(info.This());
+                SetFrozen(isolate, isolate -> GetCurrentContext ( ) , info.This(), addon->cs.database, database);
+
+                info.GetReturnValue().Set(info.This());
+}
+#line 98 "./src/objects/backup.lzz"
+void Backup::JS_transfer (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 98 "./src/objects/backup.lzz"
+                                 {
+                Backup* backup = node :: ObjectWrap :: Unwrap <Backup>(info.This());
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsInt32 ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a 32-bit signed integer" ) ; int pages = ( info [ 0 ] . As < v8 :: Int32 > ( ) ) -> Value ( ) ;
+                if ( ! backup -> db -> GetState ( ) -> open ) return ThrowTypeError ( "The database connection is not open" ) ;
+                assert(backup->db->GetState()->busy == false);
+                assert(backup->alive == true);
+
+                sqlite3_backup* backup_handle = backup->backup_handle;
+                int status = sqlite3_backup_step(backup_handle, pages) & 0xff;
+
+                Addon* addon = backup->db->GetAddon();
+                if (status == SQLITE_OK || status == SQLITE_DONE || status == SQLITE_BUSY) {
+                        int total_pages = sqlite3_backup_pagecount(backup_handle);
+                        int remaining_pages = sqlite3_backup_remaining(backup_handle);
+                        v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                        v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+                        v8::Local<v8::Object> result = v8::Object::New(isolate);
+                        result->Set(ctx, addon->cs.totalPages.Get(isolate), v8::Int32::New(isolate, total_pages)).FromJust();
+                        result->Set(ctx, addon->cs.remainingPages.Get(isolate), v8::Int32::New(isolate, remaining_pages)).FromJust();
+                        info.GetReturnValue().Set(result);
+                        if (status == SQLITE_DONE) backup->unlink = false;
+                } else {
+                        Database::ThrowSqliteError(addon, sqlite3_errstr(status), status);
+                }
+}
+#line 124 "./src/objects/backup.lzz"
+void Backup::JS_close (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 124 "./src/objects/backup.lzz"
+                              {
+                Backup* backup = node :: ObjectWrap :: Unwrap <Backup>(info.This());
+                assert(backup->db->GetState()->busy == false);
+                if (backup->alive) backup->db->RemoveBackup(backup);
+                backup->CloseHandles();
+                info.GetReturnValue().Set(info.This());
+}
+#line 4 "./src/util/data-converter.lzz"
+void DataConverter::ThrowDataConversionError (sqlite3_context * invocation, bool isBigInt)
+#line 4 "./src/util/data-converter.lzz"
+                                                                                  {
+                if (isBigInt) {
+                        ThrowRangeError((GetDataErrorPrefix() + " a bigint that was too big").c_str());
+                } else {
+                        ThrowTypeError((GetDataErrorPrefix() + " an invalid value").c_str());
+                }
+                PropagateJSError(invocation);
+}
+#line 4 "./src/util/custom-function.lzz"
+CustomFunction::CustomFunction (v8::Isolate * isolate, Database * db, char const * name, v8::Local <v8::Function> fn, bool safe_ints)
+#line 10 "./src/util/custom-function.lzz"
+  : name (name), db (db), isolate (isolate), fn (isolate, fn), safe_ints (safe_ints)
+#line 15 "./src/util/custom-function.lzz"
+                                     {}
+#line 17 "./src/util/custom-function.lzz"
+CustomFunction::~ CustomFunction ()
+#line 17 "./src/util/custom-function.lzz"
+                                  {}
+#line 19 "./src/util/custom-function.lzz"
+void CustomFunction::xDestroy (void * self)
+#line 19 "./src/util/custom-function.lzz"
+                                         {
+                delete static_cast<CustomFunction*>(self);
+}
+#line 23 "./src/util/custom-function.lzz"
+void CustomFunction::xFunc (sqlite3_context * invocation, int argc, sqlite3_value * * argv)
+#line 23 "./src/util/custom-function.lzz"
+                                                                                       {
+                CustomFunction * self = static_cast < CustomFunction * > ( sqlite3_user_data ( invocation ) ) ; v8 :: Isolate * isolate = self -> isolate ; v8 :: HandleScope scope ( isolate ) ;
+
+                v8::Local<v8::Value> args_fast[4];
+                v8::Local<v8::Value>* args = NULL;
+                if (argc != 0) {
+                        args = argc <= 4 ? args_fast : ALLOC_ARRAY<v8::Local<v8::Value>>(argc);
+                        Data::GetArgumentsJS(isolate, args, argv, argc, self->safe_ints);
+                }
+
+                v8::MaybeLocal<v8::Value> maybeReturnValue = self->fn.Get(isolate)->Call( isolate -> GetCurrentContext ( ) , v8::Undefined(isolate), argc, args);
+                if (args != args_fast) delete[] args;
+
+                if (maybeReturnValue.IsEmpty()) self->PropagateJSError(invocation);
+                else Data::ResultValueFromJS(isolate, invocation, maybeReturnValue.ToLocalChecked(), self);
+}
+#line 42 "./src/util/custom-function.lzz"
+void CustomFunction::PropagateJSError (sqlite3_context * invocation)
+#line 42 "./src/util/custom-function.lzz"
+                                                           {
+                assert(db->GetState()->was_js_error == false);
+                db->GetState()->was_js_error = true;
+                sqlite3_result_error(invocation, "", 0);
+}
+#line 48 "./src/util/custom-function.lzz"
+std::string CustomFunction::GetDataErrorPrefix ()
+#line 48 "./src/util/custom-function.lzz"
+                                         {
+                return std::string("User-defined function ") + name + "() returned";
+}
+#line 4 "./src/util/custom-aggregate.lzz"
+CustomAggregate::CustomAggregate (v8::Isolate * isolate, Database * db, char const * name, v8::Local <v8::Value> start, v8::Local <v8::Function> step, v8::Local <v8::Value> inverse, v8::Local <v8::Value> result, bool safe_ints)
+#line 13 "./src/util/custom-aggregate.lzz"
+  : CustomFunction (isolate, db, name, step, safe_ints), invoke_result (result->IsFunction()), invoke_start (start->IsFunction()), inverse (isolate, inverse->IsFunction() ? inverse.As<v8::Function>() : v8::Local<v8::Function>()), result (isolate, result->IsFunction() ? result.As<v8::Function>() : v8::Local<v8::Function>()), start (isolate, start)
+#line 19 "./src/util/custom-aggregate.lzz"
+                                      {}
+#line 21 "./src/util/custom-aggregate.lzz"
+void CustomAggregate::xStep (sqlite3_context * invocation, int argc, sqlite3_value * * argv)
+#line 21 "./src/util/custom-aggregate.lzz"
+                                                                                       {
+                xStepBase(invocation, argc, argv, &CustomAggregate::fn);
+}
+#line 25 "./src/util/custom-aggregate.lzz"
+void CustomAggregate::xInverse (sqlite3_context * invocation, int argc, sqlite3_value * * argv)
+#line 25 "./src/util/custom-aggregate.lzz"
+                                                                                          {
+                xStepBase(invocation, argc, argv, &CustomAggregate::inverse);
+}
+#line 29 "./src/util/custom-aggregate.lzz"
+void CustomAggregate::xValue (sqlite3_context * invocation)
+#line 29 "./src/util/custom-aggregate.lzz"
+                                                        {
+                xValueBase(invocation, false);
+}
+#line 33 "./src/util/custom-aggregate.lzz"
+void CustomAggregate::xFinal (sqlite3_context * invocation)
+#line 33 "./src/util/custom-aggregate.lzz"
+                                                        {
+                xValueBase(invocation, true);
+}
+#line 88 "./src/util/custom-aggregate.lzz"
+CustomAggregate::Accumulator * CustomAggregate::GetAccumulator (sqlite3_context * invocation)
+#line 88 "./src/util/custom-aggregate.lzz"
+                                                                 {
+                Accumulator* acc = static_cast<Accumulator*>(sqlite3_aggregate_context(invocation, sizeof(Accumulator)));
+                if (!acc->initialized) {
+                        assert(acc->value.IsEmpty());
+                        acc->initialized = true;
+                        if (invoke_start) {
+                                v8::MaybeLocal<v8::Value> maybeSeed = start.Get(isolate).As<v8::Function>()->Call( isolate -> GetCurrentContext ( ) , v8::Undefined(isolate), 0, NULL);
+                                if (maybeSeed.IsEmpty()) PropagateJSError(invocation);
+                                else acc->value.Reset(isolate, maybeSeed.ToLocalChecked());
+                        } else {
+                                assert(!start.IsEmpty());
+                                acc->value.Reset(isolate, start);
+                        }
+                }
+                return acc;
+}
+#line 105 "./src/util/custom-aggregate.lzz"
+void CustomAggregate::DestroyAccumulator (sqlite3_context * invocation)
+#line 105 "./src/util/custom-aggregate.lzz"
+                                                                    {
+                Accumulator* acc = static_cast<Accumulator*>(sqlite3_aggregate_context(invocation, sizeof(Accumulator)));
+                assert(acc->initialized);
+                acc->value.Reset();
+}
+#line 111 "./src/util/custom-aggregate.lzz"
+void CustomAggregate::PropagateJSError (sqlite3_context * invocation)
+#line 111 "./src/util/custom-aggregate.lzz"
+                                                           {
+                DestroyAccumulator(invocation);
+                CustomFunction::PropagateJSError(invocation);
+}
+#line 4 "./src/util/custom-table.lzz"
+CustomTable::CustomTable (v8::Isolate * isolate, Database * db, char const * name, v8::Local <v8::Function> factory)
+#line 9 "./src/util/custom-table.lzz"
+  : addon (db->GetAddon()), isolate (isolate), db (db), name (name), factory (isolate, factory)
+#line 14 "./src/util/custom-table.lzz"
+                                          {}
+#line 16 "./src/util/custom-table.lzz"
+void CustomTable::Destructor (void * self)
+#line 16 "./src/util/custom-table.lzz"
+                                           {
+                delete static_cast<CustomTable*>(self);
+}
+#line 20 "./src/util/custom-table.lzz"
+sqlite3_module CustomTable::MODULE = {
+                0,
+                xCreate,
+                xConnect,
+                xBestIndex,
+                xDisconnect,
+                xDisconnect,
+                xOpen,
+                xClose,
+                xFilter,
+                xNext,
+                xEof,
+                xColumn,
+                xRowid,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL
+        };
+#line 47 "./src/util/custom-table.lzz"
+sqlite3_module CustomTable::EPONYMOUS_MODULE = {
+                0,
+                NULL,
+                xConnect,
+                xBestIndex,
+                xDisconnect,
+                xDisconnect,
+                xOpen,
+                xClose,
+                xFilter,
+                xNext,
+                xEof,
+                xColumn,
+                xRowid,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL,
+                NULL
+        };
+#line 78 "./src/util/custom-table.lzz"
+CustomTable::VTab::VTab (CustomTable * parent, v8::Local <v8::Function> generator, std::vector <std::string> parameter_names, bool safe_ints)
+#line 83 "./src/util/custom-table.lzz"
+  : parent (parent), parameter_count (parameter_names.size()), safe_ints (safe_ints), generator (parent->isolate, generator), parameter_names (parameter_names)
+#line 88 "./src/util/custom-table.lzz"
+                                                         {
+                        ((void)base);
+}
+#line 132 "./src/util/custom-table.lzz"
+CustomTable::TempDataConverter::TempDataConverter (CustomTable * parent)
+#line 132 "./src/util/custom-table.lzz"
+  : parent (parent), status (SQLITE_OK)
+#line 134 "./src/util/custom-table.lzz"
+                                          {}
+#line 136 "./src/util/custom-table.lzz"
+void CustomTable::TempDataConverter::PropagateJSError (sqlite3_context * invocation)
+#line 136 "./src/util/custom-table.lzz"
+                                                                   {
+                        status = SQLITE_ERROR;
+                        parent->PropagateJSError();
+}
+#line 141 "./src/util/custom-table.lzz"
+std::string CustomTable::TempDataConverter::GetDataErrorPrefix ()
+#line 141 "./src/util/custom-table.lzz"
+                                                 {
+                        return std::string("Virtual table module \"") + parent->name + "\" yielded";
+}
+#line 151 "./src/util/custom-table.lzz"
+int CustomTable::xCreate (sqlite3 * db_handle, void * _self, int argc, char const * const * argv, sqlite3_vtab * * output, char * * errOutput)
+#line 151 "./src/util/custom-table.lzz"
+                                                                                                                                         {
+                return xConnect(db_handle, _self, argc, argv, output, errOutput);
+}
+#line 156 "./src/util/custom-table.lzz"
+int CustomTable::xConnect (sqlite3 * db_handle, void * _self, int argc, char const * const * argv, sqlite3_vtab * * output, char * * errOutput)
+#line 156 "./src/util/custom-table.lzz"
+                                                                                                                                          {
+                CustomTable* self = static_cast<CustomTable*>(_self);
+                v8::Isolate* isolate = self->isolate;
+                v8::HandleScope scope(isolate);
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+
+                v8::Local<v8::Value>* args = ALLOC_ARRAY<v8::Local<v8::Value>>(argc);
+                for (int i = 0; i < argc; ++i) {
+                        args[i] = StringFromUtf8(isolate, argv[i], -1);
+                }
+
+
+                v8::MaybeLocal<v8::Value> maybeReturnValue = self->factory.Get(isolate)->Call(ctx, v8::Undefined(isolate), argc, args);
+                delete[] args;
+
+                if (maybeReturnValue.IsEmpty()) {
+                        self->PropagateJSError();
+                        return SQLITE_ERROR;
+                }
+
+
+                v8::Local<v8::Array> returnValue = maybeReturnValue.ToLocalChecked().As<v8::Array>();
+                v8::Local<v8::String> sqlString = returnValue->Get(ctx, 0).ToLocalChecked().As<v8::String>();
+                v8::Local<v8::Function> generator = returnValue->Get(ctx, 1).ToLocalChecked().As<v8::Function>();
+                v8::Local<v8::Array> parameterNames = returnValue->Get(ctx, 2).ToLocalChecked().As<v8::Array>();
+                int safe_ints = returnValue->Get(ctx, 3).ToLocalChecked().As<v8::Int32>()->Value();
+                bool direct_only = returnValue->Get(ctx, 4).ToLocalChecked().As<v8::Boolean>()->Value();
+
+                v8::String::Utf8Value sql(isolate, sqlString);
+                safe_ints = safe_ints < 2 ? safe_ints : static_cast<int>(self->db->GetState()->safe_ints);
+
+
+                std::vector<std::string> parameter_names;
+                for (int i = 0, len = parameterNames->Length(); i < len; ++i) {
+                        v8::Local<v8::String> parameterName = parameterNames->Get(ctx, i).ToLocalChecked().As<v8::String>();
+                        v8::String::Utf8Value parameter_name(isolate, parameterName);
+                        parameter_names.emplace_back(*parameter_name);
+                }
+
+
+                if (sqlite3_declare_vtab(db_handle, *sql) != SQLITE_OK) {
+                        *errOutput = sqlite3_mprintf("failed to declare virtual table \"%s\"", argv[2]);
+                        return SQLITE_ERROR;
+                }
+                if (direct_only && sqlite3_vtab_config(db_handle, SQLITE_VTAB_DIRECTONLY) != SQLITE_OK) {
+                        *errOutput = sqlite3_mprintf("failed to configure virtual table \"%s\"", argv[2]);
+                        return SQLITE_ERROR;
+                }
+
+
+                *output = (new VTab(self, generator, parameter_names, safe_ints))->Downcast();
+                return SQLITE_OK;
+}
+#line 210 "./src/util/custom-table.lzz"
+int CustomTable::xDisconnect (sqlite3_vtab * vtab)
+#line 210 "./src/util/custom-table.lzz"
+                                                   {
+                delete VTab::Upcast(vtab);
+                return SQLITE_OK;
+}
+#line 215 "./src/util/custom-table.lzz"
+int CustomTable::xOpen (sqlite3_vtab * vtab, sqlite3_vtab_cursor * * output)
+#line 215 "./src/util/custom-table.lzz"
+                                                                           {
+                *output = (new Cursor())->Downcast();
+                return SQLITE_OK;
+}
+#line 220 "./src/util/custom-table.lzz"
+int CustomTable::xClose (sqlite3_vtab_cursor * cursor)
+#line 220 "./src/util/custom-table.lzz"
+                                                       {
+                delete Cursor::Upcast(cursor);
+                return SQLITE_OK;
+}
+#line 228 "./src/util/custom-table.lzz"
+int CustomTable::xFilter (sqlite3_vtab_cursor * _cursor, int idxNum, char const * idxStr, int argc, sqlite3_value * * argv)
+#line 228 "./src/util/custom-table.lzz"
+                                                                                                                         {
+                Cursor* cursor = Cursor::Upcast(_cursor);
+                VTab* vtab = cursor->GetVTab();
+                CustomTable* self = vtab->parent;
+                Addon* addon = self->addon;
+                v8::Isolate* isolate = self->isolate;
+                v8::HandleScope scope(isolate);
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+
+
+
+                v8::Local<v8::Value> args_fast[4];
+                v8::Local<v8::Value>* args = NULL;
+                int parameter_count = vtab->parameter_count;
+                if (parameter_count != 0) {
+                        args = parameter_count <= 4 ? args_fast : ALLOC_ARRAY<v8::Local<v8::Value>>(parameter_count);
+                        int argn = 0;
+                        bool safe_ints = vtab->safe_ints;
+                        for (int i = 0; i < parameter_count; ++i) {
+                                if (idxNum & 1 << i) {
+                                        args[i] = Data::GetValueJS(isolate, argv[argn++], safe_ints);
+
+
+                                        if (args[i]->IsNull()) {
+                                                if (args != args_fast) delete[] args;
+                                                cursor->done = true;
+                                                return SQLITE_OK;
+                                        }
+                                } else {
+                                        args[i] = v8::Undefined(isolate);
+                                }
+                        }
+                }
+
+
+                v8::MaybeLocal<v8::Value> maybeIterator = vtab->generator.Get(isolate)->Call(ctx, v8::Undefined(isolate), parameter_count, args);
+                if (args != args_fast) delete[] args;
+
+                if (maybeIterator.IsEmpty()) {
+                        self->PropagateJSError();
+                        return SQLITE_ERROR;
+                }
+
+
+                v8::Local<v8::Object> iterator = maybeIterator.ToLocalChecked().As<v8::Object>();
+                v8::Local<v8::Function> next = iterator->Get(ctx, addon->cs.next.Get(isolate)).ToLocalChecked().As<v8::Function>();
+                cursor->iterator.Reset(isolate, iterator);
+                cursor->next.Reset(isolate, next);
+                cursor->rowid = 0;
+
+
+                return xNext(cursor->Downcast());
+}
+#line 284 "./src/util/custom-table.lzz"
+int CustomTable::xNext (sqlite3_vtab_cursor * _cursor)
+#line 284 "./src/util/custom-table.lzz"
+                                                       {
+                Cursor* cursor = Cursor::Upcast(_cursor);
+                CustomTable* self = cursor->GetVTab()->parent;
+                Addon* addon = self->addon;
+                v8::Isolate* isolate = self->isolate;
+                v8::HandleScope scope(isolate);
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+
+                v8::Local<v8::Object> iterator = cursor->iterator.Get(isolate);
+                v8::Local<v8::Function> next = cursor->next.Get(isolate);
+
+                v8::MaybeLocal<v8::Value> maybeRecord = next->Call(ctx, iterator, 0, NULL);
+                if (maybeRecord.IsEmpty()) {
+                        self->PropagateJSError();
+                        return SQLITE_ERROR;
+                }
+
+                v8::Local<v8::Object> record = maybeRecord.ToLocalChecked().As<v8::Object>();
+                bool done = record->Get(ctx, addon->cs.done.Get(isolate)).ToLocalChecked().As<v8::Boolean>()->Value();
+                if (!done) {
+                        cursor->row.Reset(isolate, record->Get(ctx, addon->cs.value.Get(isolate)).ToLocalChecked().As<v8::Array>());
+                }
+                cursor->done = done;
+                cursor->rowid += 1;
+
+                return SQLITE_OK;
+}
+#line 313 "./src/util/custom-table.lzz"
+int CustomTable::xEof (sqlite3_vtab_cursor * cursor)
+#line 313 "./src/util/custom-table.lzz"
+                                                     {
+                return Cursor::Upcast(cursor)->done;
+}
+#line 318 "./src/util/custom-table.lzz"
+int CustomTable::xColumn (sqlite3_vtab_cursor * _cursor, sqlite3_context * invocation, int column)
+#line 318 "./src/util/custom-table.lzz"
+                                                                                                  {
+                Cursor* cursor = Cursor::Upcast(_cursor);
+                CustomTable* self = cursor->GetVTab()->parent;
+                TempDataConverter temp_data_converter(self);
+                v8::Isolate* isolate = self->isolate;
+                v8::HandleScope scope(isolate);
+
+                v8::Local<v8::Array> row = cursor->row.Get(isolate);
+                v8::MaybeLocal<v8::Value> maybeColumnValue = row->Get( isolate -> GetCurrentContext ( ) , column);
+                if (maybeColumnValue.IsEmpty()) {
+                        temp_data_converter.PropagateJSError(NULL);
+                } else {
+                        Data::ResultValueFromJS(isolate, invocation, maybeColumnValue.ToLocalChecked(), &temp_data_converter);
+                }
+                return temp_data_converter.status;
+}
+#line 336 "./src/util/custom-table.lzz"
+int CustomTable::xRowid (sqlite3_vtab_cursor * cursor, sqlite_int64 * output)
+#line 336 "./src/util/custom-table.lzz"
+                                                                             {
+                *output = Cursor::Upcast(cursor)->rowid;
+                return SQLITE_OK;
+}
+#line 343 "./src/util/custom-table.lzz"
+int CustomTable::xBestIndex (sqlite3_vtab * vtab, sqlite3_index_info * output)
+#line 343 "./src/util/custom-table.lzz"
+                                                                              {
+                int parameter_count = VTab::Upcast(vtab)->parameter_count;
+                int argument_count = 0;
+                std::vector<std::pair<int, int>> forwarded;
+
+                for (int i = 0, len = output->nConstraint; i < len; ++i) {
+                        auto item = output->aConstraint[i];
+
+
+
+
+
+                        if (item.op == SQLITE_INDEX_CONSTRAINT_LIMIT || item.op == SQLITE_INDEX_CONSTRAINT_OFFSET) {
+                                continue;
+                        }
+
+                        if (item.iColumn >= 0 && item.iColumn < parameter_count) {
+                                if (item.op != SQLITE_INDEX_CONSTRAINT_EQ) {
+                                        sqlite3_free(vtab->zErrMsg);
+                                        vtab->zErrMsg = sqlite3_mprintf(
+                                                "virtual table parameter \"%s\" can only be constrained by the '=' operator",
+                                                VTab::Upcast(vtab)->parameter_names.at(item.iColumn).c_str());
+                                        return SQLITE_ERROR;
+                                }
+                                if (!item.usable) {
+
+
+
+                                        return SQLITE_CONSTRAINT;
+                                }
+                                forwarded.emplace_back(item.iColumn, i);
+                        }
+                }
+
+
+                std::sort(forwarded.begin(), forwarded.end());
+                for (std::pair<int, int> pair : forwarded) {
+                        int bit = 1 << pair.first;
+                        if (!(output->idxNum & bit)) {
+                                output->idxNum |= bit;
+                                output->aConstraintUsage[pair.second].argvIndex = ++argument_count;
+                                output->aConstraintUsage[pair.second].omit = 1;
+                        }
+                }
+
+
+
+                output->estimatedCost = output->estimatedRows = 1000000000 / (argument_count + 1);
+                return SQLITE_OK;
+}
+#line 394 "./src/util/custom-table.lzz"
+void CustomTable::PropagateJSError ()
+#line 394 "./src/util/custom-table.lzz"
+                                {
+                assert(db->GetState()->was_js_error == false);
+                db->GetState()->was_js_error = true;
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 72 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetValueJS (v8::Isolate * isolate, sqlite3_stmt * handle, int column, bool safe_ints)
+#line 72 "./src/util/data.lzz"
+                                                                                                                {
+                switch ( sqlite3_column_type ( handle , column ) ) { case SQLITE_INTEGER : if ( safe_ints ) { return v8 :: BigInt :: New ( isolate , sqlite3_column_int64 ( handle , column ) ) ; } case SQLITE_FLOAT : return v8 :: Number :: New ( isolate , sqlite3_column_double ( handle , column ) ) ; case SQLITE_TEXT : return StringFromUtf8 ( isolate , reinterpret_cast < const char * > ( sqlite3_column_text ( handle , column ) ) , sqlite3_column_bytes ( handle , column ) ) ; case SQLITE_BLOB : return node :: Buffer :: Copy ( isolate , static_cast < const char * > ( sqlite3_column_blob ( handle , column ) ) , sqlite3_column_bytes ( handle , column ) ) . ToLocalChecked ( ) ; default : assert ( sqlite3_column_type ( handle , column ) == SQLITE_NULL ) ; return v8 :: Null ( isolate ) ; } assert ( false ) ; ;
+  }
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 76 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetValueJS (v8::Isolate * isolate, sqlite3_value * value, bool safe_ints)
+#line 76 "./src/util/data.lzz"
+                                                                                                    {
+                switch ( sqlite3_value_type ( value ) ) { case SQLITE_INTEGER : if ( safe_ints ) { return v8 :: BigInt :: New ( isolate , sqlite3_value_int64 ( value ) ) ; } case SQLITE_FLOAT : return v8 :: Number :: New ( isolate , sqlite3_value_double ( value ) ) ; case SQLITE_TEXT : return StringFromUtf8 ( isolate , reinterpret_cast < const char * > ( sqlite3_value_text ( value ) ) , sqlite3_value_bytes ( value ) ) ; case SQLITE_BLOB : return node :: Buffer :: Copy ( isolate , static_cast < const char * > ( sqlite3_value_blob ( value ) ) , sqlite3_value_bytes ( value ) ) . ToLocalChecked ( ) ; default : assert ( sqlite3_value_type ( value ) == SQLITE_NULL ) ; return v8 :: Null ( isolate ) ; } assert ( false ) ; ;
+  }
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 80 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetFlatRowJS (v8::Isolate * isolate, v8::Local <v8::Context> ctx, sqlite3_stmt * handle, bool safe_ints)
+#line 80 "./src/util/data.lzz"
+                                                                                                                                  {
+                v8::Local<v8::Object> row = v8::Object::New(isolate);
+                int column_count = sqlite3_column_count(handle);
+                for (int i = 0; i < column_count; ++i) {
+                        row->Set(ctx,
+                                InternalizedFromUtf8(isolate, sqlite3_column_name(handle, i), -1),
+                                Data::GetValueJS(isolate, handle, i, safe_ints)).FromJust();
+                }
+                return row;
+  }
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 91 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetExpandedRowJS (v8::Isolate * isolate, v8::Local <v8::Context> ctx, sqlite3_stmt * handle, bool safe_ints)
+#line 91 "./src/util/data.lzz"
+                                                                                                                                      {
+                v8::Local<v8::Object> row = v8::Object::New(isolate);
+                int column_count = sqlite3_column_count(handle);
+                for (int i = 0; i < column_count; ++i) {
+                        const char* table_raw = sqlite3_column_table_name(handle, i);
+                        v8::Local<v8::String> table = InternalizedFromUtf8(isolate, table_raw == NULL ? "$" : table_raw, -1);
+                        v8::Local<v8::String> column = InternalizedFromUtf8(isolate, sqlite3_column_name(handle, i), -1);
+                        v8::Local<v8::Value> value = Data::GetValueJS(isolate, handle, i, safe_ints);
+                        if (row->HasOwnProperty(ctx, table).FromJust()) {
+                                row->Get(ctx, table).ToLocalChecked().As<v8::Object>()->Set(ctx, column, value).FromJust();
+                        } else {
+                                v8::Local<v8::Object> nested = v8::Object::New(isolate);
+                                row->Set(ctx, table, nested).FromJust();
+                                nested->Set(ctx, column, value).FromJust();
+                        }
+                }
+                return row;
+  }
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 110 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetRawRowJS (v8::Isolate * isolate, v8::Local <v8::Context> ctx, sqlite3_stmt * handle, bool safe_ints)
+#line 110 "./src/util/data.lzz"
+                                                                                                                                 {
+                v8::Local<v8::Array> row = v8::Array::New(isolate);
+                int column_count = sqlite3_column_count(handle);
+                for (int i = 0; i < column_count; ++i) {
+                        row->Set(ctx, i, Data::GetValueJS(isolate, handle, i, safe_ints)).FromJust();
+                }
+                return row;
+  }
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 119 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetRowJS (v8::Isolate * isolate, v8::Local <v8::Context> ctx, sqlite3_stmt * handle, bool safe_ints, char mode)
+#line 119 "./src/util/data.lzz"
+                                                                                                                                         {
+                if (mode == FLAT) return GetFlatRowJS(isolate, ctx, handle, safe_ints);
+                if (mode == PLUCK) return GetValueJS(isolate, handle, 0, safe_ints);
+                if (mode == EXPAND) return GetExpandedRowJS(isolate, ctx, handle, safe_ints);
+                if (mode == RAW) return GetRawRowJS(isolate, ctx, handle, safe_ints);
+                assert(false);
+                return v8::Local<v8::Value>();
+  }
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 128 "./src/util/data.lzz"
+  void GetArgumentsJS (v8::Isolate * isolate, v8::Local <v8::Value> * out, sqlite3_value * * values, int argument_count, bool safe_ints)
+#line 128 "./src/util/data.lzz"
+                                                                                                                                         {
+                assert(argument_count > 0);
+                for (int i = 0; i < argument_count; ++i) {
+                        out[i] = Data::GetValueJS(isolate, values[i], safe_ints);
+                }
+  }
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 135 "./src/util/data.lzz"
+  int BindValueFromJS (v8::Isolate * isolate, sqlite3_stmt * handle, int index, v8::Local <v8::Value> value)
+#line 135 "./src/util/data.lzz"
+                                                                                                               {
+                if ( value -> IsNumber ( ) ) { return sqlite3_bind_double ( handle , index , value . As < v8 :: Number > ( ) -> Value ( ) ) ; } else if ( value -> IsBigInt ( ) ) { bool lossless ; int64_t v = value . As < v8 :: BigInt > ( ) -> Int64Value ( & lossless ) ; if ( lossless ) { return sqlite3_bind_int64 ( handle , index , v ) ; } } else if ( value -> IsString ( ) ) { v8 :: String :: Utf8Value utf8 ( isolate , value . As < v8 :: String > ( ) ) ; return sqlite3_bind_text ( handle , index , * utf8 , utf8 . length ( ) , SQLITE_TRANSIENT ) ; } else if ( node :: Buffer :: HasInstance ( value ) ) { const char * data = node :: Buffer :: Data ( value ) ; return sqlite3_bind_blob ( handle , index , data ? data : "" , node :: Buffer :: Length ( value ) , SQLITE_TRANSIENT ) ; } else if ( value -> IsNull ( ) || value -> IsUndefined ( ) ) { return sqlite3_bind_null ( handle , index ) ; } ;
+                return value->IsBigInt() ? SQLITE_TOOBIG : -1;
+  }
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 140 "./src/util/data.lzz"
+  void ResultValueFromJS (v8::Isolate * isolate, sqlite3_context * invocation, v8::Local <v8::Value> value, DataConverter * converter)
+#line 140 "./src/util/data.lzz"
+                                                                                                                                        {
+                if ( value -> IsNumber ( ) ) { return sqlite3_result_double ( invocation , value . As < v8 :: Number > ( ) -> Value ( ) ) ; } else if ( value -> IsBigInt ( ) ) { bool lossless ; int64_t v = value . As < v8 :: BigInt > ( ) -> Int64Value ( & lossless ) ; if ( lossless ) { return sqlite3_result_int64 ( invocation , v ) ; } } else if ( value -> IsString ( ) ) { v8 :: String :: Utf8Value utf8 ( isolate , value . As < v8 :: String > ( ) ) ; return sqlite3_result_text ( invocation , * utf8 , utf8 . length ( ) , SQLITE_TRANSIENT ) ; } else if ( node :: Buffer :: HasInstance ( value ) ) { const char * data = node :: Buffer :: Data ( value ) ; return sqlite3_result_blob ( invocation , data ? data : "" , node :: Buffer :: Length ( value ) , SQLITE_TRANSIENT ) ; } else if ( value -> IsNull ( ) || value -> IsUndefined ( ) ) { return sqlite3_result_null ( invocation ) ; } ;
+                converter->ThrowDataConversionError(invocation, value->IsBigInt());
+  }
+}
+#line 4 "./src/util/binder.lzz"
+Binder::Binder (sqlite3_stmt * _handle)
+#line 4 "./src/util/binder.lzz"
+                                               {
+                handle = _handle;
+                param_count = sqlite3_bind_parameter_count(_handle);
+                anon_index = 0;
+                success = true;
+}
+#line 11 "./src/util/binder.lzz"
+bool Binder::Bind (v8::FunctionCallbackInfo <v8 :: Value> const & info, int argc, Statement * stmt)
+#line 11 "./src/util/binder.lzz"
+                                                                  {
+                assert(anon_index == 0);
+                Result result = BindArgs(info, argc, stmt);
+                if (success && result.count != param_count) {
+                        if (result.count < param_count) {
+                                if (!result.bound_object && stmt->GetBindMap( info . GetIsolate ( ) )->GetSize()) {
+                                        Fail(ThrowTypeError, "Missing named parameters");
+                                } else {
+                                        Fail(ThrowRangeError, "Too few parameter values were provided");
+                                }
+                        } else {
+                                Fail(ThrowRangeError, "Too many parameter values were provided");
+                        }
+                }
+                return success;
+}
+#line 55 "./src/util/binder.lzz"
+void Binder::Fail (void (* Throw) (char const *), char const * message)
+#line 55 "./src/util/binder.lzz"
+                                                                     {
+                assert(success == true);
+                assert((Throw == NULL) == (message == NULL));
+                assert(Throw == ThrowError || Throw == ThrowTypeError || Throw == ThrowRangeError || Throw == NULL);
+                if (Throw) Throw(message);
+                success = false;
+}
+#line 63 "./src/util/binder.lzz"
+int Binder::NextAnonIndex ()
+#line 63 "./src/util/binder.lzz"
+                            {
+                while (sqlite3_bind_parameter_name(handle, ++anon_index) != NULL) {}
+                return anon_index;
+}
+#line 69 "./src/util/binder.lzz"
+void Binder::BindValue (v8::Isolate * isolate, v8::Local <v8::Value> value, int index)
+#line 69 "./src/util/binder.lzz"
+                                                                                    {
+                int status = Data::BindValueFromJS(isolate, handle, index, value);
+                if (status != SQLITE_OK) {
+                        switch (status) {
+                                case -1:
+                                        return Fail(ThrowTypeError, "SQLite3 can only bind numbers, strings, bigints, buffers, and null");
+                                case SQLITE_TOOBIG:
+                                        return Fail(ThrowRangeError, "The bound string, buffer, or bigint is too big");
+                                case SQLITE_RANGE:
+                                        return Fail(ThrowRangeError, "Too many parameter values were provided");
+                                case SQLITE_NOMEM:
+                                        return Fail(ThrowError, "Out of memory");
+                                default:
+                                        return Fail(ThrowError, "An unexpected error occured while trying to bind parameters");
+                        }
+                        assert(false);
+                }
+}
+#line 90 "./src/util/binder.lzz"
+int Binder::BindArray (v8::Isolate * isolate, v8::Local <v8::Array> arr)
+#line 90 "./src/util/binder.lzz"
+                                                                      {
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+                uint32_t length = arr->Length();
+                if (length > INT_MAX) {
+                        Fail(ThrowRangeError, "Too many parameter values were provided");
+                        return 0;
+                }
+                int len = static_cast<int>(length);
+                for (int i = 0; i < len; ++i) {
+                        v8::MaybeLocal<v8::Value> maybeValue = arr->Get(ctx, i);
+                        if (maybeValue.IsEmpty()) {
+                                Fail(NULL, NULL);
+                                return i;
+                        }
+                        BindValue(isolate, maybeValue.ToLocalChecked(), NextAnonIndex());
+                        if (!success) {
+                                return i;
+                        }
+                }
+                return len;
+}
+#line 116 "./src/util/binder.lzz"
+int Binder::BindObject (v8::Isolate * isolate, v8::Local <v8::Object> obj, Statement * stmt)
+#line 116 "./src/util/binder.lzz"
+                                                                                         {
+                v8 :: Local < v8 :: Context > ctx = isolate -> GetCurrentContext ( ) ;
+                BindMap* bind_map = stmt->GetBindMap(isolate);
+                BindMap::Pair* pairs = bind_map->GetPairs();
+                int len = bind_map->GetSize();
+
+                for (int i = 0; i < len; ++i) {
+                        v8::Local<v8::String> key = pairs[i].GetName(isolate);
+
+
+                        v8::Maybe<bool> has_property = obj->HasOwnProperty(ctx, key);
+                        if (has_property.IsNothing()) {
+                                Fail(NULL, NULL);
+                                return i;
+                        }
+                        if (!has_property.FromJust()) {
+                                v8::String::Utf8Value param_name(isolate, key);
+                                Fail(ThrowRangeError, (std::string("Missing named parameter \"") + *param_name + "\"").c_str());
+                                return i;
+                        }
+
+
+                        v8::MaybeLocal<v8::Value> maybeValue = obj->Get(ctx, key);
+                        if (maybeValue.IsEmpty()) {
+                                Fail(NULL, NULL);
+                                return i;
+                        }
+
+                        BindValue(isolate, maybeValue.ToLocalChecked(), pairs[i].GetIndex());
+                        if (!success) {
+                                return i;
+                        }
+                }
+
+                return len;
+}
+#line 160 "./src/util/binder.lzz"
+Binder::Result Binder::BindArgs (v8::FunctionCallbackInfo <v8 :: Value> const & info, int argc, Statement * stmt)
+#line 160 "./src/util/binder.lzz"
+                                                                        {
+                v8 :: Isolate * isolate = info . GetIsolate ( ) ;
+                int count = 0;
+                bool bound_object = false;
+
+                for (int i = 0; i < argc; ++i) {
+                        v8::Local<v8::Value> arg = info[i];
+
+                        if (arg->IsArray()) {
+                                count += BindArray(isolate, arg.As<v8::Array>());
+                                if (!success) break;
+                                continue;
+                        }
+
+                        if (arg->IsObject() && !node::Buffer::HasInstance(arg)) {
+                                v8::Local<v8::Object> obj = arg.As<v8::Object>();
+                                if (IsPlainObject(isolate, obj)) {
+                                        if (bound_object) {
+                                                Fail(ThrowTypeError, "You cannot specify named parameters in two different objects");
+                                                break;
+                                        }
+                                        bound_object = true;
+
+                                        count += BindObject(isolate, obj, stmt);
+                                        if (!success) break;
+                                        continue;
+                                } else if (stmt->GetBindMap(isolate)->GetSize()) {
+                                        Fail(ThrowTypeError, "Named parameters can only be passed within plain objects");
+                                        break;
+                                }
+                        }
+
+                        BindValue(isolate, arg, NextAnonIndex());
+                        if (!success) break;
+                        count += 1;
+                }
+
+                return { count, bound_object };
+}
+#line 35 "./src/better_sqlite3.lzz"
+void Addon::JS_setErrorConstructor (v8::FunctionCallbackInfo <v8 :: Value> const & info)
+#line 35 "./src/better_sqlite3.lzz"
+                                            {
+                if ( info . Length ( ) <= ( 0 ) || ! info [ 0 ] -> IsFunction ( ) ) return ThrowTypeError ( "Expected " "first" " argument to be " "a function" ) ; v8 :: Local < v8 :: Function > SqliteError = ( info [ 0 ] . As < v8 :: Function > ( ) ) ;
+                static_cast < Addon * > ( info . Data ( ) . As < v8 :: External > ( ) -> Value ( ) ) ->SqliteError.Reset( info . GetIsolate ( ) , SqliteError);
+}
+#line 40 "./src/better_sqlite3.lzz"
+void Addon::Cleanup (void * ptr)
+#line 40 "./src/better_sqlite3.lzz"
+                                       {
+                Addon* addon = static_cast<Addon*>(ptr);
+                for (Database* db : addon->dbs) db->CloseHandles();
+                addon->dbs.clear();
+                delete addon;
+}
+#line 47 "./src/better_sqlite3.lzz"
+Addon::Addon (v8::Isolate * isolate)
+#line 47 "./src/better_sqlite3.lzz"
+  : privileged_info (NULL), next_id (0), cs (isolate)
+#line 50 "./src/better_sqlite3.lzz"
+                            {}
+#undef LZZ_INLINE
diff --git a/server/node_modules/better-sqlite3/src/better_sqlite3.hpp b/server/node_modules/better-sqlite3/src/better_sqlite3.hpp
new file mode 100644
index 0000000..27ae83b
--- /dev/null
+++ b/server/node_modules/better-sqlite3/src/better_sqlite3.hpp
@@ -0,0 +1,1036 @@
+// better_sqlite3.hpp
+//
+
+#ifndef LZZ_BETTER_SQLITE3_better_sqlite3_hpp
+#define LZZ_BETTER_SQLITE3_better_sqlite3_hpp
+#line 2 "./src/better_sqlite3.lzz"
+#include <climits>
+#include <cstdio>
+#include <cstring>
+#include <string>
+#include <vector>
+#include <set>
+#include <unordered_map>
+#include <algorithm>
+#include <sqlite3.h>
+#include <node.h>
+#include <node_object_wrap.h>
+#include <node_buffer.h>
+#line 145 "./src/util/macros.lzz"
+void SetPrototypeGetter(
+	v8::Isolate* isolate,
+	v8::Local<v8::External> data,
+	v8::Local<v8::FunctionTemplate> recv,
+	const char* name,
+	v8::AccessorNameGetterCallback func
+);
+#line 36 "./src/util/binder.lzz"
+	static bool IsPlainObject(v8::Isolate* isolate, v8::Local<v8::Object> obj);
+#define LZZ_INLINE inline
+#line 20 "./src/util/macros.lzz"
+v8::Local <v8::String> StringFromUtf8 (v8::Isolate * isolate, char const * data, int length);
+#line 23 "./src/util/macros.lzz"
+v8::Local <v8::String> InternalizedFromUtf8 (v8::Isolate * isolate, char const * data, int length);
+#line 26 "./src/util/macros.lzz"
+v8::Local <v8::Value> InternalizedFromUtf8OrNull (v8::Isolate * isolate, char const * data, int length);
+#line 30 "./src/util/macros.lzz"
+v8::Local <v8::String> InternalizedFromLatin1 (v8::Isolate * isolate, char const * str);
+#line 34 "./src/util/macros.lzz"
+void SetFrozen (v8::Isolate * isolate, v8::Local <v8::Context> ctx, v8::Local <v8::Object> obj, v8::Global <v8::String> & key, v8::Local <v8::Value> value);
+#line 38 "./src/util/macros.lzz"
+void ThrowError (char const * message);
+#line 39 "./src/util/macros.lzz"
+void ThrowTypeError (char const * message);
+#line 40 "./src/util/macros.lzz"
+void ThrowRangeError (char const * message);
+#line 92 "./src/util/macros.lzz"
+bool IS_SKIPPED (char c);
+#line 97 "./src/util/macros.lzz"
+template <typename T>
+#line 97 "./src/util/macros.lzz"
+T * ALLOC_ARRAY (size_t count);
+#line 102 "./src/util/macros.lzz"
+template <typename T>
+#line 102 "./src/util/macros.lzz"
+void FREE_ARRAY (T * array_pointer);
+#line 106 "./src/util/macros.lzz"
+v8::Local <v8::FunctionTemplate> NewConstructorTemplate (v8::Isolate * isolate, v8::Local <v8::External> data, v8::FunctionCallback func, char const * name);
+#line 117 "./src/util/macros.lzz"
+void SetPrototypeMethod (v8::Isolate * isolate, v8::Local <v8::External> data, v8::Local <v8::FunctionTemplate> recv, char const * name, v8::FunctionCallback func);
+#line 130 "./src/util/macros.lzz"
+void SetPrototypeSymbolMethod (v8::Isolate * isolate, v8::Local <v8::External> data, v8::Local <v8::FunctionTemplate> recv, v8::Local <v8::Symbol> symbol, v8::FunctionCallback func);
+#line 1 "./src/util/constants.lzz"
+class CS
+{
+#line 2 "./src/util/constants.lzz"
+public:
+#line 4 "./src/util/constants.lzz"
+  v8::Local <v8::String> Code (v8::Isolate * isolate, int code);
+#line 10 "./src/util/constants.lzz"
+  explicit CS (v8::Isolate * isolate);
+#line 140 "./src/util/constants.lzz"
+  v8::Global <v8::String> database;
+#line 141 "./src/util/constants.lzz"
+  v8::Global <v8::String> reader;
+#line 142 "./src/util/constants.lzz"
+  v8::Global <v8::String> source;
+#line 143 "./src/util/constants.lzz"
+  v8::Global <v8::String> memory;
+#line 144 "./src/util/constants.lzz"
+  v8::Global <v8::String> readonly;
+#line 145 "./src/util/constants.lzz"
+  v8::Global <v8::String> name;
+#line 146 "./src/util/constants.lzz"
+  v8::Global <v8::String> next;
+#line 147 "./src/util/constants.lzz"
+  v8::Global <v8::String> length;
+#line 148 "./src/util/constants.lzz"
+  v8::Global <v8::String> done;
+#line 149 "./src/util/constants.lzz"
+  v8::Global <v8::String> value;
+#line 150 "./src/util/constants.lzz"
+  v8::Global <v8::String> changes;
+#line 151 "./src/util/constants.lzz"
+  v8::Global <v8::String> lastInsertRowid;
+#line 152 "./src/util/constants.lzz"
+  v8::Global <v8::String> statement;
+#line 153 "./src/util/constants.lzz"
+  v8::Global <v8::String> column;
+#line 154 "./src/util/constants.lzz"
+  v8::Global <v8::String> table;
+#line 155 "./src/util/constants.lzz"
+  v8::Global <v8::String> type;
+#line 156 "./src/util/constants.lzz"
+  v8::Global <v8::String> totalPages;
+#line 157 "./src/util/constants.lzz"
+  v8::Global <v8::String> remainingPages;
+#line 159 "./src/util/constants.lzz"
+private:
+#line 161 "./src/util/constants.lzz"
+  static void SetString (v8::Isolate * isolate, v8::Global <v8::String> & constant, char const * str);
+#line 165 "./src/util/constants.lzz"
+  void SetCode (v8::Isolate * isolate, int code, char const * str);
+#line 171 "./src/util/constants.lzz"
+  std::unordered_map <int, v8::Global<v8::String> > codes;
+};
+#line 1 "./src/util/bind-map.lzz"
+class BindMap
+{
+#line 2 "./src/util/bind-map.lzz"
+public:
+#line 6 "./src/util/bind-map.lzz"
+  class Pair
+  {
+#line 6 "./src/util/bind-map.lzz"
+    friend class BindMap;
+#line 7 "./src/util/bind-map.lzz"
+  public:
+#line 9 "./src/util/bind-map.lzz"
+    int GetIndex ();
+#line 13 "./src/util/bind-map.lzz"
+    v8::Local <v8::String> GetName (v8::Isolate * isolate);
+#line 17 "./src/util/bind-map.lzz"
+  private:
+#line 19 "./src/util/bind-map.lzz"
+    explicit Pair (v8::Isolate * isolate, char const * name, int index);
+#line 22 "./src/util/bind-map.lzz"
+    explicit Pair (v8::Isolate * isolate, Pair * pair);
+#line 25 "./src/util/bind-map.lzz"
+    v8::Global <v8::String> const name;
+#line 26 "./src/util/bind-map.lzz"
+    int const index;
+  };
+#line 29 "./src/util/bind-map.lzz"
+  explicit BindMap (char _);
+#line 36 "./src/util/bind-map.lzz"
+  ~ BindMap ();
+#line 41 "./src/util/bind-map.lzz"
+  Pair * GetPairs ();
+#line 45 "./src/util/bind-map.lzz"
+  int GetSize ();
+#line 50 "./src/util/bind-map.lzz"
+  void Add (v8::Isolate * isolate, char const * name, int index);
+#line 56 "./src/util/bind-map.lzz"
+private:
+#line 58 "./src/util/bind-map.lzz"
+  void Grow (v8::Isolate * isolate);
+#line 70 "./src/util/bind-map.lzz"
+  Pair * pairs;
+#line 71 "./src/util/bind-map.lzz"
+  int capacity;
+#line 72 "./src/util/bind-map.lzz"
+  int length;
+};
+#line 20 "./src/better_sqlite3.lzz"
+struct Addon;
+#line 21 "./src/better_sqlite3.lzz"
+class Statement;
+#line 22 "./src/better_sqlite3.lzz"
+class Backup;
+#line 1 "./src/objects/database.lzz"
+class Database : public node::ObjectWrap
+{
+#line 2 "./src/objects/database.lzz"
+public:
+#line 4 "./src/objects/database.lzz"
+  static v8::Local <v8 :: Function> Init (v8::Isolate * isolate, v8::Local <v8 :: External> data);
+#line 23 "./src/objects/database.lzz"
+  class CompareDatabase
+  {
+#line 23 "./src/objects/database.lzz"
+  public:
+#line 24 "./src/objects/database.lzz"
+    bool operator () (Database const * const a, Database const * const b) const;
+  };
+#line 28 "./src/objects/database.lzz"
+  class CompareStatement
+  {
+#line 28 "./src/objects/database.lzz"
+  public:
+#line 29 "./src/objects/database.lzz"
+    bool operator () (Statement const * const a, Statement const * const b) const;
+  };
+#line 33 "./src/objects/database.lzz"
+  class CompareBackup
+  {
+#line 33 "./src/objects/database.lzz"
+  public:
+#line 34 "./src/objects/database.lzz"
+    bool operator () (Backup const * const a, Backup const * const b) const;
+  };
+#line 40 "./src/objects/database.lzz"
+  void ThrowDatabaseError ();
+#line 44 "./src/objects/database.lzz"
+  static void ThrowSqliteError (Addon * addon, sqlite3 * db_handle);
+#line 48 "./src/objects/database.lzz"
+  static void ThrowSqliteError (Addon * addon, char const * message, int code);
+#line 64 "./src/objects/database.lzz"
+  bool Log (v8::Isolate * isolate, sqlite3_stmt * handle);
+#line 77 "./src/objects/database.lzz"
+  void AddStatement (Statement * stmt);
+#line 78 "./src/objects/database.lzz"
+  void RemoveStatement (Statement * stmt);
+#line 81 "./src/objects/database.lzz"
+  void AddBackup (Backup * backup);
+#line 82 "./src/objects/database.lzz"
+  void RemoveBackup (Backup * backup);
+#line 86 "./src/objects/database.lzz"
+  struct State
+  {
+#line 87 "./src/objects/database.lzz"
+    bool const open;
+#line 88 "./src/objects/database.lzz"
+    bool busy;
+#line 89 "./src/objects/database.lzz"
+    bool const safe_ints;
+#line 90 "./src/objects/database.lzz"
+    bool const unsafe_mode;
+#line 91 "./src/objects/database.lzz"
+    bool was_js_error;
+#line 92 "./src/objects/database.lzz"
+    bool const has_logger;
+#line 93 "./src/objects/database.lzz"
+    unsigned short int iterators;
+#line 94 "./src/objects/database.lzz"
+    Addon * const addon;
+  };
+#line 96 "./src/objects/database.lzz"
+  State * GetState ();
+#line 99 "./src/objects/database.lzz"
+  sqlite3 * GetHandle ();
+#line 102 "./src/objects/database.lzz"
+  Addon * GetAddon ();
+#line 107 "./src/objects/database.lzz"
+  void CloseHandles ();
+#line 119 "./src/objects/database.lzz"
+  ~ Database ();
+#line 124 "./src/objects/database.lzz"
+private:
+#line 126 "./src/objects/database.lzz"
+  explicit Database (v8::Isolate * isolate, Addon * addon, sqlite3 * db_handle, v8::Local <v8::Value> logger);
+#line 149 "./src/objects/database.lzz"
+  static void JS_new (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 201 "./src/objects/database.lzz"
+  static void JS_prepare (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 217 "./src/objects/database.lzz"
+  static void JS_exec (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 257 "./src/objects/database.lzz"
+  static void JS_backup (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 275 "./src/objects/database.lzz"
+  static void JS_serialize (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 297 "./src/objects/database.lzz"
+  static void JS_function (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 321 "./src/objects/database.lzz"
+  static void JS_aggregate (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 350 "./src/objects/database.lzz"
+  static void JS_table (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 370 "./src/objects/database.lzz"
+  static void JS_loadExtension (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 392 "./src/objects/database.lzz"
+  static void JS_close (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 402 "./src/objects/database.lzz"
+  static void JS_defaultSafeIntegers (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 408 "./src/objects/database.lzz"
+  static void JS_unsafeMode (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 415 "./src/objects/database.lzz"
+  static void JS_open (v8::Local <v8 :: Name> _, v8::PropertyCallbackInfo <v8 :: Value> const & info);
+#line 419 "./src/objects/database.lzz"
+  static void JS_inTransaction (v8::Local <v8 :: Name> _, v8::PropertyCallbackInfo <v8 :: Value> const & info);
+#line 424 "./src/objects/database.lzz"
+  static bool Deserialize (v8::Local <v8::Object> buffer, Addon * addon, sqlite3 * db_handle, bool readonly);
+#line 449 "./src/objects/database.lzz"
+  static void FreeSerialization (char * data, void * _);
+#line 453 "./src/objects/database.lzz"
+  static int const MAX_BUFFER_SIZE = node::Buffer::kMaxLength > INT_MAX ? INT_MAX : static_cast<int>(node::Buffer::kMaxLength);
+#line 454 "./src/objects/database.lzz"
+  static int const MAX_STRING_SIZE = v8::String::kMaxLength > INT_MAX ? INT_MAX : static_cast<int>(v8::String::kMaxLength);
+#line 456 "./src/objects/database.lzz"
+  sqlite3 * const db_handle;
+#line 457 "./src/objects/database.lzz"
+  bool open;
+#line 458 "./src/objects/database.lzz"
+  bool busy;
+#line 459 "./src/objects/database.lzz"
+  bool safe_ints;
+#line 460 "./src/objects/database.lzz"
+  bool unsafe_mode;
+#line 461 "./src/objects/database.lzz"
+  bool was_js_error;
+#line 462 "./src/objects/database.lzz"
+  bool const has_logger;
+#line 463 "./src/objects/database.lzz"
+  unsigned short int iterators;
+#line 464 "./src/objects/database.lzz"
+  Addon * const addon;
+#line 465 "./src/objects/database.lzz"
+  v8::Global <v8::Value> const logger;
+#line 466 "./src/objects/database.lzz"
+  std::set <Statement*, CompareStatement> stmts;
+#line 467 "./src/objects/database.lzz"
+  std::set <Backup*, CompareBackup> backups;
+};
+#line 1 "./src/objects/statement.lzz"
+class Statement : public node::ObjectWrap
+{
+#line 1 "./src/objects/statement.lzz"
+  friend class StatementIterator;
+#line 2 "./src/objects/statement.lzz"
+public:
+#line 4 "./src/objects/statement.lzz"
+  static v8::Local <v8 :: Function> Init (v8::Isolate * isolate, v8::Local <v8 :: External> data);
+#line 21 "./src/objects/statement.lzz"
+  static bool Compare (Statement const * const a, Statement const * const b);
+#line 26 "./src/objects/statement.lzz"
+  BindMap * GetBindMap (v8::Isolate * isolate);
+#line 39 "./src/objects/statement.lzz"
+  void CloseHandles ();
+#line 46 "./src/objects/statement.lzz"
+  ~ Statement ();
+#line 52 "./src/objects/statement.lzz"
+private:
+#line 55 "./src/objects/statement.lzz"
+  class Extras
+  {
+#line 55 "./src/objects/statement.lzz"
+    friend class Statement;
+#line 56 "./src/objects/statement.lzz"
+    explicit Extras (sqlite3_uint64 id);
+#line 57 "./src/objects/statement.lzz"
+    BindMap bind_map;
+#line 58 "./src/objects/statement.lzz"
+    sqlite3_uint64 const id;
+  };
+#line 61 "./src/objects/statement.lzz"
+  explicit Statement (Database * db, sqlite3_stmt * handle, sqlite3_uint64 id, bool returns_data);
+#line 85 "./src/objects/statement.lzz"
+  static void JS_new (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 156 "./src/objects/statement.lzz"
+  static void JS_run (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 179 "./src/objects/statement.lzz"
+  static void JS_get (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 194 "./src/objects/statement.lzz"
+  static void JS_all (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 215 "./src/objects/statement.lzz"
+  static void JS_iterate (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 225 "./src/objects/statement.lzz"
+  static void JS_bind (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 236 "./src/objects/statement.lzz"
+  static void JS_pluck (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 247 "./src/objects/statement.lzz"
+  static void JS_expand (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 258 "./src/objects/statement.lzz"
+  static void JS_raw (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 269 "./src/objects/statement.lzz"
+  static void JS_safeIntegers (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 278 "./src/objects/statement.lzz"
+  static void JS_columns (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 321 "./src/objects/statement.lzz"
+  static void JS_busy (v8::Local <v8 :: Name> _, v8::PropertyCallbackInfo <v8 :: Value> const & info);
+#line 326 "./src/objects/statement.lzz"
+  Database * const db;
+#line 327 "./src/objects/statement.lzz"
+  sqlite3_stmt * const handle;
+#line 328 "./src/objects/statement.lzz"
+  Extras * const extras;
+#line 329 "./src/objects/statement.lzz"
+  bool alive;
+#line 330 "./src/objects/statement.lzz"
+  bool locked;
+#line 331 "./src/objects/statement.lzz"
+  bool bound;
+#line 332 "./src/objects/statement.lzz"
+  bool has_bind_map;
+#line 333 "./src/objects/statement.lzz"
+  bool safe_ints;
+#line 334 "./src/objects/statement.lzz"
+  char mode;
+#line 335 "./src/objects/statement.lzz"
+  bool const returns_data;
+};
+#line 1 "./src/objects/statement-iterator.lzz"
+class StatementIterator : public node::ObjectWrap
+{
+#line 2 "./src/objects/statement-iterator.lzz"
+public:
+#line 4 "./src/objects/statement-iterator.lzz"
+  static v8::Local <v8 :: Function> Init (v8::Isolate * isolate, v8::Local <v8 :: External> data);
+#line 15 "./src/objects/statement-iterator.lzz"
+  ~ StatementIterator ();
+#line 17 "./src/objects/statement-iterator.lzz"
+private:
+#line 19 "./src/objects/statement-iterator.lzz"
+  explicit StatementIterator (Statement * stmt, bool bound);
+#line 38 "./src/objects/statement-iterator.lzz"
+  static void JS_new (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 57 "./src/objects/statement-iterator.lzz"
+  static void JS_next (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 64 "./src/objects/statement-iterator.lzz"
+  static void JS_return (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 71 "./src/objects/statement-iterator.lzz"
+  static void JS_symbolIterator (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 75 "./src/objects/statement-iterator.lzz"
+  void Next (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 100 "./src/objects/statement-iterator.lzz"
+  void Return (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 105 "./src/objects/statement-iterator.lzz"
+  void Throw ();
+#line 111 "./src/objects/statement-iterator.lzz"
+  void Cleanup ();
+#line 119 "./src/objects/statement-iterator.lzz"
+  static v8::Local <v8::Object> NewRecord (v8::Isolate * isolate, v8::Local <v8::Context> ctx, v8::Local <v8::Value> value, Addon * addon, bool done);
+#line 126 "./src/objects/statement-iterator.lzz"
+  static v8::Local <v8::Object> DoneRecord (v8::Isolate * isolate, Addon * addon);
+#line 130 "./src/objects/statement-iterator.lzz"
+  Statement * const stmt;
+#line 131 "./src/objects/statement-iterator.lzz"
+  sqlite3_stmt * const handle;
+#line 132 "./src/objects/statement-iterator.lzz"
+  Database::State * const db_state;
+#line 133 "./src/objects/statement-iterator.lzz"
+  bool const bound;
+#line 134 "./src/objects/statement-iterator.lzz"
+  bool const safe_ints;
+#line 135 "./src/objects/statement-iterator.lzz"
+  char const mode;
+#line 136 "./src/objects/statement-iterator.lzz"
+  bool alive;
+#line 137 "./src/objects/statement-iterator.lzz"
+  bool logged;
+};
+#line 1 "./src/objects/backup.lzz"
+class Backup : public node::ObjectWrap
+{
+#line 2 "./src/objects/backup.lzz"
+public:
+#line 4 "./src/objects/backup.lzz"
+  static v8::Local <v8 :: Function> Init (v8::Isolate * isolate, v8::Local <v8 :: External> data);
+#line 12 "./src/objects/backup.lzz"
+  static bool Compare (Backup const * const a, Backup const * const b);
+#line 17 "./src/objects/backup.lzz"
+  void CloseHandles ();
+#line 28 "./src/objects/backup.lzz"
+  ~ Backup ();
+#line 33 "./src/objects/backup.lzz"
+private:
+#line 35 "./src/objects/backup.lzz"
+  explicit Backup (Database * db, sqlite3 * dest_handle, sqlite3_backup * backup_handle, sqlite3_uint64 id, bool unlink);
+#line 55 "./src/objects/backup.lzz"
+  static void JS_new (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 98 "./src/objects/backup.lzz"
+  static void JS_transfer (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 124 "./src/objects/backup.lzz"
+  static void JS_close (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 132 "./src/objects/backup.lzz"
+  Database * const db;
+#line 133 "./src/objects/backup.lzz"
+  sqlite3 * const dest_handle;
+#line 134 "./src/objects/backup.lzz"
+  sqlite3_backup * const backup_handle;
+#line 135 "./src/objects/backup.lzz"
+  sqlite3_uint64 const id;
+#line 136 "./src/objects/backup.lzz"
+  bool alive;
+#line 137 "./src/objects/backup.lzz"
+  bool unlink;
+};
+#line 1 "./src/util/data-converter.lzz"
+class DataConverter
+{
+#line 2 "./src/util/data-converter.lzz"
+public:
+#line 4 "./src/util/data-converter.lzz"
+  void ThrowDataConversionError (sqlite3_context * invocation, bool isBigInt);
+#line 13 "./src/util/data-converter.lzz"
+protected:
+#line 15 "./src/util/data-converter.lzz"
+  virtual void PropagateJSError (sqlite3_context * invocation) = 0;
+#line 16 "./src/util/data-converter.lzz"
+  virtual std::string GetDataErrorPrefix () = 0;
+};
+#line 1 "./src/util/custom-function.lzz"
+class CustomFunction : protected DataConverter
+{
+#line 2 "./src/util/custom-function.lzz"
+public:
+#line 4 "./src/util/custom-function.lzz"
+  explicit CustomFunction (v8::Isolate * isolate, Database * db, char const * name, v8::Local <v8::Function> fn, bool safe_ints);
+#line 17 "./src/util/custom-function.lzz"
+  virtual ~ CustomFunction ();
+#line 19 "./src/util/custom-function.lzz"
+  static void xDestroy (void * self);
+#line 23 "./src/util/custom-function.lzz"
+  static void xFunc (sqlite3_context * invocation, int argc, sqlite3_value * * argv);
+#line 40 "./src/util/custom-function.lzz"
+protected:
+#line 42 "./src/util/custom-function.lzz"
+  void PropagateJSError (sqlite3_context * invocation);
+#line 48 "./src/util/custom-function.lzz"
+  std::string GetDataErrorPrefix ();
+#line 52 "./src/util/custom-function.lzz"
+private:
+#line 53 "./src/util/custom-function.lzz"
+  std::string const name;
+#line 54 "./src/util/custom-function.lzz"
+  Database * const db;
+#line 55 "./src/util/custom-function.lzz"
+protected:
+#line 56 "./src/util/custom-function.lzz"
+  v8::Isolate * const isolate;
+#line 57 "./src/util/custom-function.lzz"
+  v8::Global <v8::Function> const fn;
+#line 58 "./src/util/custom-function.lzz"
+  bool const safe_ints;
+};
+#line 1 "./src/util/custom-aggregate.lzz"
+class CustomAggregate : public CustomFunction
+{
+#line 2 "./src/util/custom-aggregate.lzz"
+public:
+#line 4 "./src/util/custom-aggregate.lzz"
+  explicit CustomAggregate (v8::Isolate * isolate, Database * db, char const * name, v8::Local <v8::Value> start, v8::Local <v8::Function> step, v8::Local <v8::Value> inverse, v8::Local <v8::Value> result, bool safe_ints);
+#line 21 "./src/util/custom-aggregate.lzz"
+  static void xStep (sqlite3_context * invocation, int argc, sqlite3_value * * argv);
+#line 25 "./src/util/custom-aggregate.lzz"
+  static void xInverse (sqlite3_context * invocation, int argc, sqlite3_value * * argv);
+#line 29 "./src/util/custom-aggregate.lzz"
+  static void xValue (sqlite3_context * invocation);
+#line 33 "./src/util/custom-aggregate.lzz"
+  static void xFinal (sqlite3_context * invocation);
+#line 37 "./src/util/custom-aggregate.lzz"
+private:
+#line 39 "./src/util/custom-aggregate.lzz"
+  static void xStepBase (sqlite3_context * invocation, int argc, sqlite3_value * * argv, v8::Global <v8::Function> const CustomAggregate::* ptrtm);
+#line 58 "./src/util/custom-aggregate.lzz"
+  static void xValueBase (sqlite3_context * invocation, bool is_final);
+#line 82 "./src/util/custom-aggregate.lzz"
+  struct Accumulator
+  {
+#line 82 "./src/util/custom-aggregate.lzz"
+  public:
+#line 83 "./src/util/custom-aggregate.lzz"
+    v8::Global <v8::Value> value;
+#line 84 "./src/util/custom-aggregate.lzz"
+    bool initialized;
+#line 85 "./src/util/custom-aggregate.lzz"
+    bool is_window;
+  };
+#line 88 "./src/util/custom-aggregate.lzz"
+  Accumulator * GetAccumulator (sqlite3_context * invocation);
+#line 105 "./src/util/custom-aggregate.lzz"
+  static void DestroyAccumulator (sqlite3_context * invocation);
+#line 111 "./src/util/custom-aggregate.lzz"
+  void PropagateJSError (sqlite3_context * invocation);
+#line 116 "./src/util/custom-aggregate.lzz"
+  bool const invoke_result;
+#line 117 "./src/util/custom-aggregate.lzz"
+  bool const invoke_start;
+#line 118 "./src/util/custom-aggregate.lzz"
+  v8::Global <v8::Function> const inverse;
+#line 119 "./src/util/custom-aggregate.lzz"
+  v8::Global <v8::Function> const result;
+#line 120 "./src/util/custom-aggregate.lzz"
+  v8::Global <v8::Value> const start;
+};
+#line 1 "./src/util/custom-table.lzz"
+class CustomTable
+{
+#line 2 "./src/util/custom-table.lzz"
+public:
+#line 4 "./src/util/custom-table.lzz"
+  explicit CustomTable (v8::Isolate * isolate, Database * db, char const * name, v8::Local <v8::Function> factory);
+#line 16 "./src/util/custom-table.lzz"
+  static void Destructor (void * self);
+#line 20 "./src/util/custom-table.lzz"
+  static sqlite3_module MODULE;
+#line 47 "./src/util/custom-table.lzz"
+  static sqlite3_module EPONYMOUS_MODULE;
+#line 74 "./src/util/custom-table.lzz"
+private:
+#line 77 "./src/util/custom-table.lzz"
+  class VTab
+  {
+#line 77 "./src/util/custom-table.lzz"
+    friend class CustomTable;
+#line 78 "./src/util/custom-table.lzz"
+    explicit VTab (CustomTable * parent, v8::Local <v8::Function> generator, std::vector <std::string> parameter_names, bool safe_ints);
+#line 92 "./src/util/custom-table.lzz"
+    static CustomTable::VTab * Upcast (sqlite3_vtab * vtab);
+#line 96 "./src/util/custom-table.lzz"
+    sqlite3_vtab * Downcast ();
+#line 100 "./src/util/custom-table.lzz"
+    sqlite3_vtab base;
+#line 101 "./src/util/custom-table.lzz"
+    CustomTable * const parent;
+#line 102 "./src/util/custom-table.lzz"
+    int const parameter_count;
+#line 103 "./src/util/custom-table.lzz"
+    bool const safe_ints;
+#line 104 "./src/util/custom-table.lzz"
+    v8::Global <v8::Function> const generator;
+#line 105 "./src/util/custom-table.lzz"
+    std::vector <std::string> const parameter_names;
+  };
+#line 109 "./src/util/custom-table.lzz"
+  class Cursor
+  {
+#line 109 "./src/util/custom-table.lzz"
+    friend class CustomTable;
+#line 110 "./src/util/custom-table.lzz"
+    static CustomTable::Cursor * Upcast (sqlite3_vtab_cursor * cursor);
+#line 114 "./src/util/custom-table.lzz"
+    sqlite3_vtab_cursor * Downcast ();
+#line 118 "./src/util/custom-table.lzz"
+    CustomTable::VTab * GetVTab ();
+#line 122 "./src/util/custom-table.lzz"
+    sqlite3_vtab_cursor base;
+#line 123 "./src/util/custom-table.lzz"
+    v8::Global <v8::Object> iterator;
+#line 124 "./src/util/custom-table.lzz"
+    v8::Global <v8::Function> next;
+#line 125 "./src/util/custom-table.lzz"
+    v8::Global <v8::Array> row;
+#line 126 "./src/util/custom-table.lzz"
+    bool done;
+#line 127 "./src/util/custom-table.lzz"
+    sqlite_int64 rowid;
+  };
+#line 131 "./src/util/custom-table.lzz"
+  class TempDataConverter : DataConverter
+  {
+#line 131 "./src/util/custom-table.lzz"
+    friend class CustomTable;
+#line 132 "./src/util/custom-table.lzz"
+    explicit TempDataConverter (CustomTable * parent);
+#line 136 "./src/util/custom-table.lzz"
+    void PropagateJSError (sqlite3_context * invocation);
+#line 141 "./src/util/custom-table.lzz"
+    std::string GetDataErrorPrefix ();
+#line 145 "./src/util/custom-table.lzz"
+    CustomTable * const parent;
+#line 146 "./src/util/custom-table.lzz"
+    int status;
+  };
+#line 151 "./src/util/custom-table.lzz"
+  static int xCreate (sqlite3 * db_handle, void * _self, int argc, char const * const * argv, sqlite3_vtab * * output, char * * errOutput);
+#line 156 "./src/util/custom-table.lzz"
+  static int xConnect (sqlite3 * db_handle, void * _self, int argc, char const * const * argv, sqlite3_vtab * * output, char * * errOutput);
+#line 210 "./src/util/custom-table.lzz"
+  static int xDisconnect (sqlite3_vtab * vtab);
+#line 215 "./src/util/custom-table.lzz"
+  static int xOpen (sqlite3_vtab * vtab, sqlite3_vtab_cursor * * output);
+#line 220 "./src/util/custom-table.lzz"
+  static int xClose (sqlite3_vtab_cursor * cursor);
+#line 228 "./src/util/custom-table.lzz"
+  static int xFilter (sqlite3_vtab_cursor * _cursor, int idxNum, char const * idxStr, int argc, sqlite3_value * * argv);
+#line 284 "./src/util/custom-table.lzz"
+  static int xNext (sqlite3_vtab_cursor * _cursor);
+#line 313 "./src/util/custom-table.lzz"
+  static int xEof (sqlite3_vtab_cursor * cursor);
+#line 318 "./src/util/custom-table.lzz"
+  static int xColumn (sqlite3_vtab_cursor * _cursor, sqlite3_context * invocation, int column);
+#line 336 "./src/util/custom-table.lzz"
+  static int xRowid (sqlite3_vtab_cursor * cursor, sqlite_int64 * output);
+#line 343 "./src/util/custom-table.lzz"
+  static int xBestIndex (sqlite3_vtab * vtab, sqlite3_index_info * output);
+#line 394 "./src/util/custom-table.lzz"
+  void PropagateJSError ();
+#line 399 "./src/util/custom-table.lzz"
+  Addon * const addon;
+#line 400 "./src/util/custom-table.lzz"
+  v8::Isolate * const isolate;
+#line 401 "./src/util/custom-table.lzz"
+  Database * const db;
+#line 402 "./src/util/custom-table.lzz"
+  std::string const name;
+#line 403 "./src/util/custom-table.lzz"
+  v8::Global <v8::Function> const factory;
+};
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 72 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetValueJS (v8::Isolate * isolate, sqlite3_stmt * handle, int column, bool safe_ints);
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 76 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetValueJS (v8::Isolate * isolate, sqlite3_value * value, bool safe_ints);
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 80 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetFlatRowJS (v8::Isolate * isolate, v8::Local <v8::Context> ctx, sqlite3_stmt * handle, bool safe_ints);
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 91 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetExpandedRowJS (v8::Isolate * isolate, v8::Local <v8::Context> ctx, sqlite3_stmt * handle, bool safe_ints);
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 110 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetRawRowJS (v8::Isolate * isolate, v8::Local <v8::Context> ctx, sqlite3_stmt * handle, bool safe_ints);
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 119 "./src/util/data.lzz"
+  v8::Local <v8::Value> GetRowJS (v8::Isolate * isolate, v8::Local <v8::Context> ctx, sqlite3_stmt * handle, bool safe_ints, char mode);
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 128 "./src/util/data.lzz"
+  void GetArgumentsJS (v8::Isolate * isolate, v8::Local <v8::Value> * out, sqlite3_value * * values, int argument_count, bool safe_ints);
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 135 "./src/util/data.lzz"
+  int BindValueFromJS (v8::Isolate * isolate, sqlite3_stmt * handle, int index, v8::Local <v8::Value> value);
+}
+#line 65 "./src/util/data.lzz"
+namespace Data
+{
+#line 140 "./src/util/data.lzz"
+  void ResultValueFromJS (v8::Isolate * isolate, sqlite3_context * invocation, v8::Local <v8::Value> value, DataConverter * converter);
+}
+#line 1 "./src/util/binder.lzz"
+class Binder
+{
+#line 2 "./src/util/binder.lzz"
+public:
+#line 4 "./src/util/binder.lzz"
+  explicit Binder (sqlite3_stmt * _handle);
+#line 11 "./src/util/binder.lzz"
+  bool Bind (v8::FunctionCallbackInfo <v8 :: Value> const & info, int argc, Statement * stmt);
+#line 28 "./src/util/binder.lzz"
+private:
+#line 30 "./src/util/binder.lzz"
+  struct Result
+  {
+#line 31 "./src/util/binder.lzz"
+    int count;
+#line 32 "./src/util/binder.lzz"
+    bool bound_object;
+  };
+#line 55 "./src/util/binder.lzz"
+  void Fail (void (* Throw) (char const *), char const * message);
+#line 63 "./src/util/binder.lzz"
+  int NextAnonIndex ();
+#line 69 "./src/util/binder.lzz"
+  void BindValue (v8::Isolate * isolate, v8::Local <v8::Value> value, int index);
+#line 90 "./src/util/binder.lzz"
+  int BindArray (v8::Isolate * isolate, v8::Local <v8::Array> arr);
+#line 116 "./src/util/binder.lzz"
+  int BindObject (v8::Isolate * isolate, v8::Local <v8::Object> obj, Statement * stmt);
+#line 160 "./src/util/binder.lzz"
+  Result BindArgs (v8::FunctionCallbackInfo <v8 :: Value> const & info, int argc, Statement * stmt);
+#line 200 "./src/util/binder.lzz"
+  sqlite3_stmt * handle;
+#line 201 "./src/util/binder.lzz"
+  int param_count;
+#line 202 "./src/util/binder.lzz"
+  int anon_index;
+#line 203 "./src/util/binder.lzz"
+  bool success;
+};
+#line 34 "./src/better_sqlite3.lzz"
+struct Addon
+{
+#line 35 "./src/better_sqlite3.lzz"
+  static void JS_setErrorConstructor (v8::FunctionCallbackInfo <v8 :: Value> const & info);
+#line 40 "./src/better_sqlite3.lzz"
+  static void Cleanup (void * ptr);
+#line 47 "./src/better_sqlite3.lzz"
+  explicit Addon (v8::Isolate * isolate);
+#line 52 "./src/better_sqlite3.lzz"
+  sqlite3_uint64 NextId ();
+#line 56 "./src/better_sqlite3.lzz"
+  v8::Global <v8::Function> Statement;
+#line 57 "./src/better_sqlite3.lzz"
+  v8::Global <v8::Function> StatementIterator;
+#line 58 "./src/better_sqlite3.lzz"
+  v8::Global <v8::Function> Backup;
+#line 59 "./src/better_sqlite3.lzz"
+  v8::Global <v8::Function> SqliteError;
+#line 60 "./src/better_sqlite3.lzz"
+  v8::FunctionCallbackInfo <v8 :: Value> const * privileged_info;
+#line 61 "./src/better_sqlite3.lzz"
+  sqlite3_uint64 next_id;
+#line 62 "./src/better_sqlite3.lzz"
+  CS cs;
+#line 63 "./src/better_sqlite3.lzz"
+  std::set <Database*, Database::CompareDatabase> dbs;
+};
+#line 20 "./src/util/macros.lzz"
+LZZ_INLINE v8::Local <v8::String> StringFromUtf8 (v8::Isolate * isolate, char const * data, int length)
+#line 20 "./src/util/macros.lzz"
+                                                                                                {
+        return v8::String::NewFromUtf8(isolate, data, v8::NewStringType::kNormal, length).ToLocalChecked();
+}
+#line 23 "./src/util/macros.lzz"
+LZZ_INLINE v8::Local <v8::String> InternalizedFromUtf8 (v8::Isolate * isolate, char const * data, int length)
+#line 23 "./src/util/macros.lzz"
+                                                                                                      {
+        return v8::String::NewFromUtf8(isolate, data, v8::NewStringType::kInternalized, length).ToLocalChecked();
+}
+#line 26 "./src/util/macros.lzz"
+LZZ_INLINE v8::Local <v8::Value> InternalizedFromUtf8OrNull (v8::Isolate * isolate, char const * data, int length)
+#line 26 "./src/util/macros.lzz"
+                                                                                                           {
+        if (data == NULL) return v8::Null(isolate);
+        return InternalizedFromUtf8(isolate, data, length);
+}
+#line 30 "./src/util/macros.lzz"
+LZZ_INLINE v8::Local <v8::String> InternalizedFromLatin1 (v8::Isolate * isolate, char const * str)
+#line 30 "./src/util/macros.lzz"
+                                                                                           {
+        return v8::String::NewFromOneByte(isolate, reinterpret_cast<const uint8_t*>(str), v8::NewStringType::kInternalized).ToLocalChecked();
+}
+#line 34 "./src/util/macros.lzz"
+LZZ_INLINE void SetFrozen (v8::Isolate * isolate, v8::Local <v8::Context> ctx, v8::Local <v8::Object> obj, v8::Global <v8::String> & key, v8::Local <v8::Value> value)
+#line 34 "./src/util/macros.lzz"
+                                                                                                                                                            {
+        obj->DefineOwnProperty(ctx, key.Get(isolate), value, static_cast<v8::PropertyAttribute>(v8::DontDelete | v8::ReadOnly)).FromJust();
+}
+#line 92 "./src/util/macros.lzz"
+LZZ_INLINE bool IS_SKIPPED (char c)
+#line 92 "./src/util/macros.lzz"
+                               {
+        return c == ' ' || c == ';' || (c >= '\t' && c <= '\r');
+}
+#line 97 "./src/util/macros.lzz"
+template <typename T>
+#line 97 "./src/util/macros.lzz"
+LZZ_INLINE T * ALLOC_ARRAY (size_t count)
+#line 97 "./src/util/macros.lzz"
+                                                      {
+        return static_cast<T*>(::operator new[](count * sizeof(T)));
+}
+#line 102 "./src/util/macros.lzz"
+template <typename T>
+#line 102 "./src/util/macros.lzz"
+LZZ_INLINE void FREE_ARRAY (T * array_pointer)
+#line 102 "./src/util/macros.lzz"
+                                                           {
+        ::operator delete[](array_pointer);
+}
+#line 9 "./src/util/bind-map.lzz"
+LZZ_INLINE int BindMap::Pair::GetIndex ()
+#line 9 "./src/util/bind-map.lzz"
+                                              {
+                                return index;
+}
+#line 13 "./src/util/bind-map.lzz"
+LZZ_INLINE v8::Local <v8::String> BindMap::Pair::GetName (v8::Isolate * isolate)
+#line 13 "./src/util/bind-map.lzz"
+                                                                                   {
+                                return name.Get(isolate);
+}
+#line 41 "./src/util/bind-map.lzz"
+LZZ_INLINE BindMap::Pair * BindMap::GetPairs ()
+#line 41 "./src/util/bind-map.lzz"
+                                {
+                return pairs;
+}
+#line 45 "./src/util/bind-map.lzz"
+LZZ_INLINE int BindMap::GetSize ()
+#line 45 "./src/util/bind-map.lzz"
+                             {
+                return length;
+}
+#line 77 "./src/objects/database.lzz"
+LZZ_INLINE void Database::AddStatement (Statement * stmt)
+#line 77 "./src/objects/database.lzz"
+                                                  { stmts.insert(stmts.end(), stmt);
+}
+#line 78 "./src/objects/database.lzz"
+LZZ_INLINE void Database::RemoveStatement (Statement * stmt)
+#line 78 "./src/objects/database.lzz"
+                                                     { stmts.erase(stmt);
+}
+#line 81 "./src/objects/database.lzz"
+LZZ_INLINE void Database::AddBackup (Backup * backup)
+#line 81 "./src/objects/database.lzz"
+                                              { backups.insert(backups.end(), backup);
+}
+#line 82 "./src/objects/database.lzz"
+LZZ_INLINE void Database::RemoveBackup (Backup * backup)
+#line 82 "./src/objects/database.lzz"
+                                                 { backups.erase(backup);
+}
+#line 96 "./src/objects/database.lzz"
+LZZ_INLINE Database::State * Database::GetState ()
+#line 96 "./src/objects/database.lzz"
+                                 {
+                return reinterpret_cast<State*>(&open);
+}
+#line 99 "./src/objects/database.lzz"
+LZZ_INLINE sqlite3 * Database::GetHandle ()
+#line 99 "./src/objects/database.lzz"
+                                    {
+                return db_handle;
+}
+#line 102 "./src/objects/database.lzz"
+LZZ_INLINE Addon * Database::GetAddon ()
+#line 102 "./src/objects/database.lzz"
+                                 {
+                return addon;
+}
+#line 21 "./src/objects/statement.lzz"
+LZZ_INLINE bool Statement::Compare (Statement const * const a, Statement const * const b)
+#line 21 "./src/objects/statement.lzz"
+                                                                                         {
+                return a->extras->id < b->extras->id;
+}
+#line 119 "./src/objects/statement-iterator.lzz"
+LZZ_INLINE v8::Local <v8::Object> StatementIterator::NewRecord (v8::Isolate * isolate, v8::Local <v8::Context> ctx, v8::Local <v8::Value> value, Addon * addon, bool done)
+#line 119 "./src/objects/statement-iterator.lzz"
+                                                                                                                                                             {
+                v8::Local<v8::Object> record = v8::Object::New(isolate);
+                record->Set(ctx, addon->cs.value.Get(isolate), value).FromJust();
+                record->Set(ctx, addon->cs.done.Get(isolate), v8::Boolean::New(isolate, done)).FromJust();
+                return record;
+}
+#line 126 "./src/objects/statement-iterator.lzz"
+LZZ_INLINE v8::Local <v8::Object> StatementIterator::DoneRecord (v8::Isolate * isolate, Addon * addon)
+#line 126 "./src/objects/statement-iterator.lzz"
+                                                                                           {
+                return NewRecord(isolate, isolate -> GetCurrentContext ( ) , v8::Undefined(isolate), addon, true);
+}
+#line 12 "./src/objects/backup.lzz"
+LZZ_INLINE bool Backup::Compare (Backup const * const a, Backup const * const b)
+#line 12 "./src/objects/backup.lzz"
+                                                                                   {
+                return a->id < b->id;
+}
+#line 39 "./src/util/custom-aggregate.lzz"
+LZZ_INLINE void CustomAggregate::xStepBase (sqlite3_context * invocation, int argc, sqlite3_value * * argv, v8::Global <v8::Function> const CustomAggregate::* ptrtm)
+#line 39 "./src/util/custom-aggregate.lzz"
+                                                                                                                                                          {
+                CustomAggregate * self = static_cast < CustomAggregate * > ( sqlite3_user_data ( invocation ) ) ; v8 :: Isolate * isolate = self -> isolate ; v8 :: HandleScope scope ( isolate ) ; Accumulator * acc = self -> GetAccumulator ( invocation ) ; if ( acc -> value . IsEmpty ( ) ) return ;
+
+                v8::Local<v8::Value> args_fast[5];
+                v8::Local<v8::Value>* args = argc <= 4 ? args_fast : ALLOC_ARRAY<v8::Local<v8::Value>>(argc + 1);
+                args[0] = acc->value.Get(isolate);
+                if (argc != 0) Data::GetArgumentsJS(isolate, args + 1, argv, argc, self->safe_ints);
+
+                v8::MaybeLocal<v8::Value> maybeReturnValue = (self->*ptrtm).Get(isolate)->Call( isolate -> GetCurrentContext ( ) , v8::Undefined(isolate), argc + 1, args);
+                if (args != args_fast) delete[] args;
+
+                if (maybeReturnValue.IsEmpty()) {
+                        self->PropagateJSError(invocation);
+                } else {
+                        v8::Local<v8::Value> returnValue = maybeReturnValue.ToLocalChecked();
+                        if (!returnValue->IsUndefined()) acc->value.Reset(isolate, returnValue);
+                }
+}
+#line 58 "./src/util/custom-aggregate.lzz"
+LZZ_INLINE void CustomAggregate::xValueBase (sqlite3_context * invocation, bool is_final)
+#line 58 "./src/util/custom-aggregate.lzz"
+                                                                                  {
+                CustomAggregate * self = static_cast < CustomAggregate * > ( sqlite3_user_data ( invocation ) ) ; v8 :: Isolate * isolate = self -> isolate ; v8 :: HandleScope scope ( isolate ) ; Accumulator * acc = self -> GetAccumulator ( invocation ) ; if ( acc -> value . IsEmpty ( ) ) return ;
+
+                if (!is_final) {
+                        acc->is_window = true;
+                } else if (acc->is_window) {
+                        DestroyAccumulator(invocation);
+                        return;
+                }
+
+                v8::Local<v8::Value> result = acc->value.Get(isolate);
+                if (self->invoke_result) {
+                        v8::MaybeLocal<v8::Value> maybeResult = self->result.Get(isolate)->Call( isolate -> GetCurrentContext ( ) , v8::Undefined(isolate), 1, &result);
+                        if (maybeResult.IsEmpty()) {
+                                self->PropagateJSError(invocation);
+                                return;
+                        }
+                        result = maybeResult.ToLocalChecked();
+                }
+
+                Data::ResultValueFromJS(isolate, invocation, result, self);
+                if (is_final) DestroyAccumulator(invocation);
+}
+#line 92 "./src/util/custom-table.lzz"
+LZZ_INLINE CustomTable::VTab * CustomTable::VTab::Upcast (sqlite3_vtab * vtab)
+#line 92 "./src/util/custom-table.lzz"
+                                                                            {
+                        return reinterpret_cast<VTab*>(vtab);
+}
+#line 96 "./src/util/custom-table.lzz"
+LZZ_INLINE sqlite3_vtab * CustomTable::VTab::Downcast ()
+#line 96 "./src/util/custom-table.lzz"
+                                                {
+                        return reinterpret_cast<sqlite3_vtab*>(this);
+}
+#line 110 "./src/util/custom-table.lzz"
+LZZ_INLINE CustomTable::Cursor * CustomTable::Cursor::Upcast (sqlite3_vtab_cursor * cursor)
+#line 110 "./src/util/custom-table.lzz"
+                                                                                       {
+                        return reinterpret_cast<Cursor*>(cursor);
+}
+#line 114 "./src/util/custom-table.lzz"
+LZZ_INLINE sqlite3_vtab_cursor * CustomTable::Cursor::Downcast ()
+#line 114 "./src/util/custom-table.lzz"
+                                                       {
+                        return reinterpret_cast<sqlite3_vtab_cursor*>(this);
+}
+#line 118 "./src/util/custom-table.lzz"
+LZZ_INLINE CustomTable::VTab * CustomTable::Cursor::GetVTab ()
+#line 118 "./src/util/custom-table.lzz"
+                                                    {
+                        return VTab::Upcast(base.pVtab);
+}
+#line 52 "./src/better_sqlite3.lzz"
+LZZ_INLINE sqlite3_uint64 Addon::NextId ()
+#line 52 "./src/better_sqlite3.lzz"
+                                       {
+                return next_id++;
+}
+#undef LZZ_INLINE
+#endif
diff --git a/server/node_modules/bindings/LICENSE.md b/server/node_modules/bindings/LICENSE.md
new file mode 100644
index 0000000..5a92289
--- /dev/null
+++ b/server/node_modules/bindings/LICENSE.md
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2012 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/bindings/README.md b/server/node_modules/bindings/README.md
new file mode 100644
index 0000000..5b3e7a8
--- /dev/null
+++ b/server/node_modules/bindings/README.md
@@ -0,0 +1,98 @@
+node-bindings
+=============
+### Helper module for loading your native module's `.node` file
+
+This is a helper module for authors of Node.js native addon modules.
+It is basically the "swiss army knife" of `require()`ing your native module's
+`.node` file.
+
+Throughout the course of Node's native addon history, addons have ended up being
+compiled in a variety of different places, depending on which build tool and which
+version of node was used. To make matters worse, now the `gyp` build tool can
+produce either a __Release__ or __Debug__ build, each being built into different
+locations.
+
+This module checks _all_ the possible locations that a native addon would be built
+at, and returns the first one that loads successfully.
+
+
+Installation
+------------
+
+Install with `npm`:
+
+``` bash
+$ npm install --save bindings
+```
+
+Or add it to the `"dependencies"` section of your `package.json` file.
+
+
+Example
+-------
+
+`require()`ing the proper bindings file for the current node version, platform
+and architecture is as simple as:
+
+``` js
+var bindings = require('bindings')('binding.node')
+
+// Use your bindings defined in your C files
+bindings.your_c_function()
+```
+
+
+Nice Error Output
+-----------------
+
+When the `.node` file could not be loaded, `node-bindings` throws an Error with
+a nice error message telling you exactly what was tried. You can also check the
+`err.tries` Array property.
+
+```
+Error: Could not load the bindings file. Tried:
+ → /Users/nrajlich/ref/build/binding.node
+ → /Users/nrajlich/ref/build/Debug/binding.node
+ → /Users/nrajlich/ref/build/Release/binding.node
+ → /Users/nrajlich/ref/out/Debug/binding.node
+ → /Users/nrajlich/ref/Debug/binding.node
+ → /Users/nrajlich/ref/out/Release/binding.node
+ → /Users/nrajlich/ref/Release/binding.node
+ → /Users/nrajlich/ref/build/default/binding.node
+ → /Users/nrajlich/ref/compiled/0.8.2/darwin/x64/binding.node
+    at bindings (/Users/nrajlich/ref/node_modules/bindings/bindings.js:84:13)
+    at Object.<anonymous> (/Users/nrajlich/ref/lib/ref.js:5:47)
+    at Module._compile (module.js:449:26)
+    at Object.Module._extensions..js (module.js:467:10)
+    at Module.load (module.js:356:32)
+    at Function.Module._load (module.js:312:12)
+    ...
+```
+
+The searching for the `.node` file will originate from the first directory in which has a `package.json` file is found.
+
+License
+-------
+
+(The MIT License)
+
+Copyright (c) 2012 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/bindings/bindings.js b/server/node_modules/bindings/bindings.js
new file mode 100644
index 0000000..727413a
--- /dev/null
+++ b/server/node_modules/bindings/bindings.js
@@ -0,0 +1,221 @@
+/**
+ * Module dependencies.
+ */
+
+var fs = require('fs'),
+  path = require('path'),
+  fileURLToPath = require('file-uri-to-path'),
+  join = path.join,
+  dirname = path.dirname,
+  exists =
+    (fs.accessSync &&
+      function(path) {
+        try {
+          fs.accessSync(path);
+        } catch (e) {
+          return false;
+        }
+        return true;
+      }) ||
+    fs.existsSync ||
+    path.existsSync,
+  defaults = {
+    arrow: process.env.NODE_BINDINGS_ARROW || ' → ',
+    compiled: process.env.NODE_BINDINGS_COMPILED_DIR || 'compiled',
+    platform: process.platform,
+    arch: process.arch,
+    nodePreGyp:
+      'node-v' +
+      process.versions.modules +
+      '-' +
+      process.platform +
+      '-' +
+      process.arch,
+    version: process.versions.node,
+    bindings: 'bindings.node',
+    try: [
+      // node-gyp's linked version in the "build" dir
+      ['module_root', 'build', 'bindings'],
+      // node-waf and gyp_addon (a.k.a node-gyp)
+      ['module_root', 'build', 'Debug', 'bindings'],
+      ['module_root', 'build', 'Release', 'bindings'],
+      // Debug files, for development (legacy behavior, remove for node v0.9)
+      ['module_root', 'out', 'Debug', 'bindings'],
+      ['module_root', 'Debug', 'bindings'],
+      // Release files, but manually compiled (legacy behavior, remove for node v0.9)
+      ['module_root', 'out', 'Release', 'bindings'],
+      ['module_root', 'Release', 'bindings'],
+      // Legacy from node-waf, node <= 0.4.x
+      ['module_root', 'build', 'default', 'bindings'],
+      // Production "Release" buildtype binary (meh...)
+      ['module_root', 'compiled', 'version', 'platform', 'arch', 'bindings'],
+      // node-qbs builds
+      ['module_root', 'addon-build', 'release', 'install-root', 'bindings'],
+      ['module_root', 'addon-build', 'debug', 'install-root', 'bindings'],
+      ['module_root', 'addon-build', 'default', 'install-root', 'bindings'],
+      // node-pre-gyp path ./lib/binding/{node_abi}-{platform}-{arch}
+      ['module_root', 'lib', 'binding', 'nodePreGyp', 'bindings']
+    ]
+  };
+
+/**
+ * The main `bindings()` function loads the compiled bindings for a given module.
+ * It uses V8's Error API to determine the parent filename that this function is
+ * being invoked from, which is then used to find the root directory.
+ */
+
+function bindings(opts) {
+  // Argument surgery
+  if (typeof opts == 'string') {
+    opts = { bindings: opts };
+  } else if (!opts) {
+    opts = {};
+  }
+
+  // maps `defaults` onto `opts` object
+  Object.keys(defaults).map(function(i) {
+    if (!(i in opts)) opts[i] = defaults[i];
+  });
+
+  // Get the module root
+  if (!opts.module_root) {
+    opts.module_root = exports.getRoot(exports.getFileName());
+  }
+
+  // Ensure the given bindings name ends with .node
+  if (path.extname(opts.bindings) != '.node') {
+    opts.bindings += '.node';
+  }
+
+  // https://github.com/webpack/webpack/issues/4175#issuecomment-342931035
+  var requireFunc =
+    typeof __webpack_require__ === 'function'
+      ? __non_webpack_require__
+      : require;
+
+  var tries = [],
+    i = 0,
+    l = opts.try.length,
+    n,
+    b,
+    err;
+
+  for (; i < l; i++) {
+    n = join.apply(
+      null,
+      opts.try[i].map(function(p) {
+        return opts[p] || p;
+      })
+    );
+    tries.push(n);
+    try {
+      b = opts.path ? requireFunc.resolve(n) : requireFunc(n);
+      if (!opts.path) {
+        b.path = n;
+      }
+      return b;
+    } catch (e) {
+      if (e.code !== 'MODULE_NOT_FOUND' &&
+          e.code !== 'QUALIFIED_PATH_RESOLUTION_FAILED' &&
+          !/not find/i.test(e.message)) {
+        throw e;
+      }
+    }
+  }
+
+  err = new Error(
+    'Could not locate the bindings file. Tried:\n' +
+      tries
+        .map(function(a) {
+          return opts.arrow + a;
+        })
+        .join('\n')
+  );
+  err.tries = tries;
+  throw err;
+}
+module.exports = exports = bindings;
+
+/**
+ * Gets the filename of the JavaScript file that invokes this function.
+ * Used to help find the root directory of a module.
+ * Optionally accepts an filename argument to skip when searching for the invoking filename
+ */
+
+exports.getFileName = function getFileName(calling_file) {
+  var origPST = Error.prepareStackTrace,
+    origSTL = Error.stackTraceLimit,
+    dummy = {},
+    fileName;
+
+  Error.stackTraceLimit = 10;
+
+  Error.prepareStackTrace = function(e, st) {
+    for (var i = 0, l = st.length; i < l; i++) {
+      fileName = st[i].getFileName();
+      if (fileName !== __filename) {
+        if (calling_file) {
+          if (fileName !== calling_file) {
+            return;
+          }
+        } else {
+          return;
+        }
+      }
+    }
+  };
+
+  // run the 'prepareStackTrace' function above
+  Error.captureStackTrace(dummy);
+  dummy.stack;
+
+  // cleanup
+  Error.prepareStackTrace = origPST;
+  Error.stackTraceLimit = origSTL;
+
+  // handle filename that starts with "file://"
+  var fileSchema = 'file://';
+  if (fileName.indexOf(fileSchema) === 0) {
+    fileName = fileURLToPath(fileName);
+  }
+
+  return fileName;
+};
+
+/**
+ * Gets the root directory of a module, given an arbitrary filename
+ * somewhere in the module tree. The "root directory" is the directory
+ * containing the `package.json` file.
+ *
+ *   In:  /home/nate/node-native-module/lib/index.js
+ *   Out: /home/nate/node-native-module
+ */
+
+exports.getRoot = function getRoot(file) {
+  var dir = dirname(file),
+    prev;
+  while (true) {
+    if (dir === '.') {
+      // Avoids an infinite loop in rare cases, like the REPL
+      dir = process.cwd();
+    }
+    if (
+      exists(join(dir, 'package.json')) ||
+      exists(join(dir, 'node_modules'))
+    ) {
+      // Found the 'package.json' file or 'node_modules' dir; we're done
+      return dir;
+    }
+    if (prev === dir) {
+      // Got to the top
+      throw new Error(
+        'Could not find module root given file: "' +
+          file +
+          '". Do you have a `package.json` file? '
+      );
+    }
+    // Try the parent dir next
+    prev = dir;
+    dir = join(dir, '..');
+  }
+};
diff --git a/server/node_modules/bindings/package.json b/server/node_modules/bindings/package.json
new file mode 100644
index 0000000..d027ee7
--- /dev/null
+++ b/server/node_modules/bindings/package.json
@@ -0,0 +1,28 @@
+{
+  "name": "bindings",
+  "description": "Helper module for loading your native module's .node file",
+  "keywords": [
+    "native",
+    "addon",
+    "bindings",
+    "gyp",
+    "waf",
+    "c",
+    "c++"
+  ],
+  "version": "1.5.0",
+  "author": "Nathan Rajlich <nathan@tootallnate.net> (http://tootallnate.net)",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/TooTallNate/node-bindings.git"
+  },
+  "main": "./bindings.js",
+  "bugs": {
+    "url": "https://github.com/TooTallNate/node-bindings/issues"
+  },
+  "homepage": "https://github.com/TooTallNate/node-bindings",
+  "license": "MIT",
+  "dependencies": {
+    "file-uri-to-path": "1.0.0"
+  }
+}
diff --git a/server/node_modules/bl/.travis.yml b/server/node_modules/bl/.travis.yml
new file mode 100644
index 0000000..016eaf5
--- /dev/null
+++ b/server/node_modules/bl/.travis.yml
@@ -0,0 +1,17 @@
+sudo: false
+arch:
+ - amd64
+ - ppc64le
+language: node_js
+node_js:
+  - '6'
+  - '8'
+  - '10'
+  - '12'
+  - '14'
+  - '15'
+  - lts/*
+notifications:
+  email:
+    - rod@vagg.org
+    - matteo.collina@gmail.com
diff --git a/server/node_modules/bl/BufferList.js b/server/node_modules/bl/BufferList.js
new file mode 100644
index 0000000..471ee77
--- /dev/null
+++ b/server/node_modules/bl/BufferList.js
@@ -0,0 +1,396 @@
+'use strict'
+
+const { Buffer } = require('buffer')
+const symbol = Symbol.for('BufferList')
+
+function BufferList (buf) {
+  if (!(this instanceof BufferList)) {
+    return new BufferList(buf)
+  }
+
+  BufferList._init.call(this, buf)
+}
+
+BufferList._init = function _init (buf) {
+  Object.defineProperty(this, symbol, { value: true })
+
+  this._bufs = []
+  this.length = 0
+
+  if (buf) {
+    this.append(buf)
+  }
+}
+
+BufferList.prototype._new = function _new (buf) {
+  return new BufferList(buf)
+}
+
+BufferList.prototype._offset = function _offset (offset) {
+  if (offset === 0) {
+    return [0, 0]
+  }
+
+  let tot = 0
+
+  for (let i = 0; i < this._bufs.length; i++) {
+    const _t = tot + this._bufs[i].length
+    if (offset < _t || i === this._bufs.length - 1) {
+      return [i, offset - tot]
+    }
+    tot = _t
+  }
+}
+
+BufferList.prototype._reverseOffset = function (blOffset) {
+  const bufferId = blOffset[0]
+  let offset = blOffset[1]
+
+  for (let i = 0; i < bufferId; i++) {
+    offset += this._bufs[i].length
+  }
+
+  return offset
+}
+
+BufferList.prototype.get = function get (index) {
+  if (index > this.length || index < 0) {
+    return undefined
+  }
+
+  const offset = this._offset(index)
+
+  return this._bufs[offset[0]][offset[1]]
+}
+
+BufferList.prototype.slice = function slice (start, end) {
+  if (typeof start === 'number' && start < 0) {
+    start += this.length
+  }
+
+  if (typeof end === 'number' && end < 0) {
+    end += this.length
+  }
+
+  return this.copy(null, 0, start, end)
+}
+
+BufferList.prototype.copy = function copy (dst, dstStart, srcStart, srcEnd) {
+  if (typeof srcStart !== 'number' || srcStart < 0) {
+    srcStart = 0
+  }
+
+  if (typeof srcEnd !== 'number' || srcEnd > this.length) {
+    srcEnd = this.length
+  }
+
+  if (srcStart >= this.length) {
+    return dst || Buffer.alloc(0)
+  }
+
+  if (srcEnd <= 0) {
+    return dst || Buffer.alloc(0)
+  }
+
+  const copy = !!dst
+  const off = this._offset(srcStart)
+  const len = srcEnd - srcStart
+  let bytes = len
+  let bufoff = (copy && dstStart) || 0
+  let start = off[1]
+
+  // copy/slice everything
+  if (srcStart === 0 && srcEnd === this.length) {
+    if (!copy) {
+      // slice, but full concat if multiple buffers
+      return this._bufs.length === 1
+        ? this._bufs[0]
+        : Buffer.concat(this._bufs, this.length)
+    }
+
+    // copy, need to copy individual buffers
+    for (let i = 0; i < this._bufs.length; i++) {
+      this._bufs[i].copy(dst, bufoff)
+      bufoff += this._bufs[i].length
+    }
+
+    return dst
+  }
+
+  // easy, cheap case where it's a subset of one of the buffers
+  if (bytes <= this._bufs[off[0]].length - start) {
+    return copy
+      ? this._bufs[off[0]].copy(dst, dstStart, start, start + bytes)
+      : this._bufs[off[0]].slice(start, start + bytes)
+  }
+
+  if (!copy) {
+    // a slice, we need something to copy in to
+    dst = Buffer.allocUnsafe(len)
+  }
+
+  for (let i = off[0]; i < this._bufs.length; i++) {
+    const l = this._bufs[i].length - start
+
+    if (bytes > l) {
+      this._bufs[i].copy(dst, bufoff, start)
+      bufoff += l
+    } else {
+      this._bufs[i].copy(dst, bufoff, start, start + bytes)
+      bufoff += l
+      break
+    }
+
+    bytes -= l
+
+    if (start) {
+      start = 0
+    }
+  }
+
+  // safeguard so that we don't return uninitialized memory
+  if (dst.length > bufoff) return dst.slice(0, bufoff)
+
+  return dst
+}
+
+BufferList.prototype.shallowSlice = function shallowSlice (start, end) {
+  start = start || 0
+  end = typeof end !== 'number' ? this.length : end
+
+  if (start < 0) {
+    start += this.length
+  }
+
+  if (end < 0) {
+    end += this.length
+  }
+
+  if (start === end) {
+    return this._new()
+  }
+
+  const startOffset = this._offset(start)
+  const endOffset = this._offset(end)
+  const buffers = this._bufs.slice(startOffset[0], endOffset[0] + 1)
+
+  if (endOffset[1] === 0) {
+    buffers.pop()
+  } else {
+    buffers[buffers.length - 1] = buffers[buffers.length - 1].slice(0, endOffset[1])
+  }
+
+  if (startOffset[1] !== 0) {
+    buffers[0] = buffers[0].slice(startOffset[1])
+  }
+
+  return this._new(buffers)
+}
+
+BufferList.prototype.toString = function toString (encoding, start, end) {
+  return this.slice(start, end).toString(encoding)
+}
+
+BufferList.prototype.consume = function consume (bytes) {
+  // first, normalize the argument, in accordance with how Buffer does it
+  bytes = Math.trunc(bytes)
+  // do nothing if not a positive number
+  if (Number.isNaN(bytes) || bytes <= 0) return this
+
+  while (this._bufs.length) {
+    if (bytes >= this._bufs[0].length) {
+      bytes -= this._bufs[0].length
+      this.length -= this._bufs[0].length
+      this._bufs.shift()
+    } else {
+      this._bufs[0] = this._bufs[0].slice(bytes)
+      this.length -= bytes
+      break
+    }
+  }
+
+  return this
+}
+
+BufferList.prototype.duplicate = function duplicate () {
+  const copy = this._new()
+
+  for (let i = 0; i < this._bufs.length; i++) {
+    copy.append(this._bufs[i])
+  }
+
+  return copy
+}
+
+BufferList.prototype.append = function append (buf) {
+  if (buf == null) {
+    return this
+  }
+
+  if (buf.buffer) {
+    // append a view of the underlying ArrayBuffer
+    this._appendBuffer(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength))
+  } else if (Array.isArray(buf)) {
+    for (let i = 0; i < buf.length; i++) {
+      this.append(buf[i])
+    }
+  } else if (this._isBufferList(buf)) {
+    // unwrap argument into individual BufferLists
+    for (let i = 0; i < buf._bufs.length; i++) {
+      this.append(buf._bufs[i])
+    }
+  } else {
+    // coerce number arguments to strings, since Buffer(number) does
+    // uninitialized memory allocation
+    if (typeof buf === 'number') {
+      buf = buf.toString()
+    }
+
+    this._appendBuffer(Buffer.from(buf))
+  }
+
+  return this
+}
+
+BufferList.prototype._appendBuffer = function appendBuffer (buf) {
+  this._bufs.push(buf)
+  this.length += buf.length
+}
+
+BufferList.prototype.indexOf = function (search, offset, encoding) {
+  if (encoding === undefined && typeof offset === 'string') {
+    encoding = offset
+    offset = undefined
+  }
+
+  if (typeof search === 'function' || Array.isArray(search)) {
+    throw new TypeError('The "value" argument must be one of type string, Buffer, BufferList, or Uint8Array.')
+  } else if (typeof search === 'number') {
+    search = Buffer.from([search])
+  } else if (typeof search === 'string') {
+    search = Buffer.from(search, encoding)
+  } else if (this._isBufferList(search)) {
+    search = search.slice()
+  } else if (Array.isArray(search.buffer)) {
+    search = Buffer.from(search.buffer, search.byteOffset, search.byteLength)
+  } else if (!Buffer.isBuffer(search)) {
+    search = Buffer.from(search)
+  }
+
+  offset = Number(offset || 0)
+
+  if (isNaN(offset)) {
+    offset = 0
+  }
+
+  if (offset < 0) {
+    offset = this.length + offset
+  }
+
+  if (offset < 0) {
+    offset = 0
+  }
+
+  if (search.length === 0) {
+    return offset > this.length ? this.length : offset
+  }
+
+  const blOffset = this._offset(offset)
+  let blIndex = blOffset[0] // index of which internal buffer we're working on
+  let buffOffset = blOffset[1] // offset of the internal buffer we're working on
+
+  // scan over each buffer
+  for (; blIndex < this._bufs.length; blIndex++) {
+    const buff = this._bufs[blIndex]
+
+    while (buffOffset < buff.length) {
+      const availableWindow = buff.length - buffOffset
+
+      if (availableWindow >= search.length) {
+        const nativeSearchResult = buff.indexOf(search, buffOffset)
+
+        if (nativeSearchResult !== -1) {
+          return this._reverseOffset([blIndex, nativeSearchResult])
+        }
+
+        buffOffset = buff.length - search.length + 1 // end of native search window
+      } else {
+        const revOffset = this._reverseOffset([blIndex, buffOffset])
+
+        if (this._match(revOffset, search)) {
+          return revOffset
+        }
+
+        buffOffset++
+      }
+    }
+
+    buffOffset = 0
+  }
+
+  return -1
+}
+
+BufferList.prototype._match = function (offset, search) {
+  if (this.length - offset < search.length) {
+    return false
+  }
+
+  for (let searchOffset = 0; searchOffset < search.length; searchOffset++) {
+    if (this.get(offset + searchOffset) !== search[searchOffset]) {
+      return false
+    }
+  }
+  return true
+}
+
+;(function () {
+  const methods = {
+    readDoubleBE: 8,
+    readDoubleLE: 8,
+    readFloatBE: 4,
+    readFloatLE: 4,
+    readInt32BE: 4,
+    readInt32LE: 4,
+    readUInt32BE: 4,
+    readUInt32LE: 4,
+    readInt16BE: 2,
+    readInt16LE: 2,
+    readUInt16BE: 2,
+    readUInt16LE: 2,
+    readInt8: 1,
+    readUInt8: 1,
+    readIntBE: null,
+    readIntLE: null,
+    readUIntBE: null,
+    readUIntLE: null
+  }
+
+  for (const m in methods) {
+    (function (m) {
+      if (methods[m] === null) {
+        BufferList.prototype[m] = function (offset, byteLength) {
+          return this.slice(offset, offset + byteLength)[m](0, byteLength)
+        }
+      } else {
+        BufferList.prototype[m] = function (offset = 0) {
+          return this.slice(offset, offset + methods[m])[m](0)
+        }
+      }
+    }(m))
+  }
+}())
+
+// Used internally by the class and also as an indicator of this object being
+// a `BufferList`. It's not possible to use `instanceof BufferList` in a browser
+// environment because there could be multiple different copies of the
+// BufferList class and some `BufferList`s might be `BufferList`s.
+BufferList.prototype._isBufferList = function _isBufferList (b) {
+  return b instanceof BufferList || BufferList.isBufferList(b)
+}
+
+BufferList.isBufferList = function isBufferList (b) {
+  return b != null && b[symbol]
+}
+
+module.exports = BufferList
diff --git a/server/node_modules/bl/LICENSE.md b/server/node_modules/bl/LICENSE.md
new file mode 100644
index 0000000..ecbe516
--- /dev/null
+++ b/server/node_modules/bl/LICENSE.md
@@ -0,0 +1,13 @@
+The MIT License (MIT)
+=====================
+
+Copyright (c) 2013-2019 bl contributors
+----------------------------------
+
+*bl contributors listed at <https://github.com/rvagg/bl#contributors>*
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/bl/README.md b/server/node_modules/bl/README.md
new file mode 100644
index 0000000..9680b1d
--- /dev/null
+++ b/server/node_modules/bl/README.md
@@ -0,0 +1,247 @@
+# bl *(BufferList)*
+
+[![Build Status](https://api.travis-ci.com/rvagg/bl.svg?branch=master)](https://travis-ci.com/rvagg/bl/)
+
+**A Node.js Buffer list collector, reader and streamer thingy.**
+
+[![NPM](https://nodei.co/npm/bl.svg)](https://nodei.co/npm/bl/)
+
+**bl** is a storage object for collections of Node Buffers, exposing them with the main Buffer readable API. Also works as a duplex stream so you can collect buffers from a stream that emits them and emit buffers to a stream that consumes them!
+
+The original buffers are kept intact and copies are only done as necessary. Any reads that require the use of a single original buffer will return a slice of that buffer only (which references the same memory as the original buffer). Reads that span buffers perform concatenation as required and return the results transparently.
+
+```js
+const { BufferList } = require('bl')
+
+const bl = new BufferList()
+bl.append(Buffer.from('abcd'))
+bl.append(Buffer.from('efg'))
+bl.append('hi')                     // bl will also accept & convert Strings
+bl.append(Buffer.from('j'))
+bl.append(Buffer.from([ 0x3, 0x4 ]))
+
+console.log(bl.length) // 12
+
+console.log(bl.slice(0, 10).toString('ascii')) // 'abcdefghij'
+console.log(bl.slice(3, 10).toString('ascii')) // 'defghij'
+console.log(bl.slice(3, 6).toString('ascii'))  // 'def'
+console.log(bl.slice(3, 8).toString('ascii'))  // 'defgh'
+console.log(bl.slice(5, 10).toString('ascii')) // 'fghij'
+
+console.log(bl.indexOf('def')) // 3
+console.log(bl.indexOf('asdf')) // -1
+
+// or just use toString!
+console.log(bl.toString())               // 'abcdefghij\u0003\u0004'
+console.log(bl.toString('ascii', 3, 8))  // 'defgh'
+console.log(bl.toString('ascii', 5, 10)) // 'fghij'
+
+// other standard Buffer readables
+console.log(bl.readUInt16BE(10)) // 0x0304
+console.log(bl.readUInt16LE(10)) // 0x0403
+```
+
+Give it a callback in the constructor and use it just like **[concat-stream](https://github.com/maxogden/node-concat-stream)**:
+
+```js
+const { BufferListStream } = require('bl')
+const fs = require('fs')
+
+fs.createReadStream('README.md')
+  .pipe(BufferListStream((err, data) => { // note 'new' isn't strictly required
+    // `data` is a complete Buffer object containing the full data
+    console.log(data.toString())
+  }))
+```
+
+Note that when you use the *callback* method like this, the resulting `data` parameter is a concatenation of all `Buffer` objects in the list. If you want to avoid the overhead of this concatenation (in cases of extreme performance consciousness), then avoid the *callback* method and just listen to `'end'` instead, like a standard Stream.
+
+Or to fetch a URL using [hyperquest](https://github.com/substack/hyperquest) (should work with [request](http://github.com/mikeal/request) and even plain Node http too!):
+
+```js
+const hyperquest = require('hyperquest')
+const { BufferListStream } = require('bl')
+
+const url = 'https://raw.github.com/rvagg/bl/master/README.md'
+
+hyperquest(url).pipe(BufferListStream((err, data) => {
+  console.log(data.toString())
+}))
+```
+
+Or, use it as a readable stream to recompose a list of Buffers to an output source:
+
+```js
+const { BufferListStream } = require('bl')
+const fs = require('fs')
+
+var bl = new BufferListStream()
+bl.append(Buffer.from('abcd'))
+bl.append(Buffer.from('efg'))
+bl.append(Buffer.from('hi'))
+bl.append(Buffer.from('j'))
+
+bl.pipe(fs.createWriteStream('gibberish.txt'))
+```
+
+## API
+
+  * <a href="#ctor"><code><b>new BufferList([ buf ])</b></code></a>
+  * <a href="#isBufferList"><code><b>BufferList.isBufferList(obj)</b></code></a>
+  * <a href="#length"><code>bl.<b>length</b></code></a>
+  * <a href="#append"><code>bl.<b>append(buffer)</b></code></a>
+  * <a href="#get"><code>bl.<b>get(index)</b></code></a>
+  * <a href="#indexOf"><code>bl.<b>indexOf(value[, byteOffset][, encoding])</b></code></a>
+  * <a href="#slice"><code>bl.<b>slice([ start[, end ] ])</b></code></a>
+  * <a href="#shallowSlice"><code>bl.<b>shallowSlice([ start[, end ] ])</b></code></a>
+  * <a href="#copy"><code>bl.<b>copy(dest, [ destStart, [ srcStart [, srcEnd ] ] ])</b></code></a>
+  * <a href="#duplicate"><code>bl.<b>duplicate()</b></code></a>
+  * <a href="#consume"><code>bl.<b>consume(bytes)</b></code></a>
+  * <a href="#toString"><code>bl.<b>toString([encoding, [ start, [ end ]]])</b></code></a>
+  * <a href="#readXX"><code>bl.<b>readDoubleBE()</b></code>, <code>bl.<b>readDoubleLE()</b></code>, <code>bl.<b>readFloatBE()</b></code>, <code>bl.<b>readFloatLE()</b></code>, <code>bl.<b>readInt32BE()</b></code>, <code>bl.<b>readInt32LE()</b></code>, <code>bl.<b>readUInt32BE()</b></code>, <code>bl.<b>readUInt32LE()</b></code>, <code>bl.<b>readInt16BE()</b></code>, <code>bl.<b>readInt16LE()</b></code>, <code>bl.<b>readUInt16BE()</b></code>, <code>bl.<b>readUInt16LE()</b></code>, <code>bl.<b>readInt8()</b></code>, <code>bl.<b>readUInt8()</b></code></a>
+  * <a href="#ctorStream"><code><b>new BufferListStream([ callback ])</b></code></a>
+
+--------------------------------------------------------
+<a name="ctor"></a>
+### new BufferList([ Buffer | Buffer array | BufferList | BufferList array | String ])
+No arguments are _required_ for the constructor, but you can initialise the list by passing in a single `Buffer` object or an array of `Buffer` objects.
+
+`new` is not strictly required, if you don't instantiate a new object, it will be done automatically for you so you can create a new instance simply with:
+
+```js
+const { BufferList } = require('bl')
+const bl = BufferList()
+
+// equivalent to:
+
+const { BufferList } = require('bl')
+const bl = new BufferList()
+```
+
+--------------------------------------------------------
+<a name="isBufferList"></a>
+### BufferList.isBufferList(obj)
+Determines if the passed object is a `BufferList`. It will return `true` if the passed object is an instance of `BufferList` **or** `BufferListStream` and `false` otherwise.
+
+N.B. this won't return `true` for `BufferList` or `BufferListStream` instances created by versions of this library before this static method was added.
+
+--------------------------------------------------------
+<a name="length"></a>
+### bl.length
+Get the length of the list in bytes. This is the sum of the lengths of all of the buffers contained in the list, minus any initial offset for a semi-consumed buffer at the beginning. Should accurately represent the total number of bytes that can be read from the list.
+
+--------------------------------------------------------
+<a name="append"></a>
+### bl.append(Buffer | Buffer array | BufferList | BufferList array | String)
+`append(buffer)` adds an additional buffer or BufferList to the internal list. `this` is returned so it can be chained.
+
+--------------------------------------------------------
+<a name="get"></a>
+### bl.get(index)
+`get()` will return the byte at the specified index.
+
+--------------------------------------------------------
+<a name="indexOf"></a>
+### bl.indexOf(value[, byteOffset][, encoding])
+`get()` will return the byte at the specified index.
+`indexOf()` method returns the first index at which a given element can be found in the BufferList, or -1 if it is not present.
+
+--------------------------------------------------------
+<a name="slice"></a>
+### bl.slice([ start, [ end ] ])
+`slice()` returns a new `Buffer` object containing the bytes within the range specified. Both `start` and `end` are optional and will default to the beginning and end of the list respectively.
+
+If the requested range spans a single internal buffer then a slice of that buffer will be returned which shares the original memory range of that Buffer. If the range spans multiple buffers then copy operations will likely occur to give you a uniform Buffer.
+
+--------------------------------------------------------
+<a name="shallowSlice"></a>
+### bl.shallowSlice([ start, [ end ] ])
+`shallowSlice()` returns a new `BufferList` object containing the bytes within the range specified. Both `start` and `end` are optional and will default to the beginning and end of the list respectively.
+
+No copies will be performed. All buffers in the result share memory with the original list.
+
+--------------------------------------------------------
+<a name="copy"></a>
+### bl.copy(dest, [ destStart, [ srcStart [, srcEnd ] ] ])
+`copy()` copies the content of the list in the `dest` buffer, starting from `destStart` and containing the bytes within the range specified with `srcStart` to `srcEnd`. `destStart`, `start` and `end` are optional and will default to the beginning of the `dest` buffer, and the beginning and end of the list respectively.
+
+--------------------------------------------------------
+<a name="duplicate"></a>
+### bl.duplicate()
+`duplicate()` performs a **shallow-copy** of the list. The internal Buffers remains the same, so if you change the underlying Buffers, the change will be reflected in both the original and the duplicate. This method is needed if you want to call `consume()` or `pipe()` and still keep the original list.Example:
+
+```js
+var bl = new BufferListStream()
+
+bl.append('hello')
+bl.append(' world')
+bl.append('\n')
+
+bl.duplicate().pipe(process.stdout, { end: false })
+
+console.log(bl.toString())
+```
+
+--------------------------------------------------------
+<a name="consume"></a>
+### bl.consume(bytes)
+`consume()` will shift bytes *off the start of the list*. The number of bytes consumed don't need to line up with the sizes of the internal Buffers—initial offsets will be calculated accordingly in order to give you a consistent view of the data.
+
+--------------------------------------------------------
+<a name="toString"></a>
+### bl.toString([encoding, [ start, [ end ]]])
+`toString()` will return a string representation of the buffer. The optional `start` and `end` arguments are passed on to `slice()`, while the `encoding` is passed on to `toString()` of the resulting Buffer. See the [Buffer#toString()](http://nodejs.org/docs/latest/api/buffer.html#buffer_buf_tostring_encoding_start_end) documentation for more information.
+
+--------------------------------------------------------
+<a name="readXX"></a>
+### bl.readDoubleBE(), bl.readDoubleLE(), bl.readFloatBE(), bl.readFloatLE(), bl.readInt32BE(), bl.readInt32LE(), bl.readUInt32BE(), bl.readUInt32LE(), bl.readInt16BE(), bl.readInt16LE(), bl.readUInt16BE(), bl.readUInt16LE(), bl.readInt8(), bl.readUInt8()
+
+All of the standard byte-reading methods of the `Buffer` interface are implemented and will operate across internal Buffer boundaries transparently.
+
+See the <b><code>[Buffer](http://nodejs.org/docs/latest/api/buffer.html)</code></b> documentation for how these work.
+
+--------------------------------------------------------
+<a name="ctorStream"></a>
+### new BufferListStream([ callback | Buffer | Buffer array | BufferList | BufferList array | String ])
+**BufferListStream** is a Node **[Duplex Stream](http://nodejs.org/docs/latest/api/stream.html#stream_class_stream_duplex)**, so it can be read from and written to like a standard Node stream. You can also `pipe()` to and from a **BufferListStream** instance.
+
+The constructor takes an optional callback, if supplied, the callback will be called with an error argument followed by a reference to the **bl** instance, when `bl.end()` is called (i.e. from a piped stream). This is a convenient method of collecting the entire contents of a stream, particularly when the stream is *chunky*, such as a network stream.
+
+Normally, no arguments are required for the constructor, but you can initialise the list by passing in a single `Buffer` object or an array of `Buffer` object.
+
+`new` is not strictly required, if you don't instantiate a new object, it will be done automatically for you so you can create a new instance simply with:
+
+```js
+const { BufferListStream } = require('bl')
+const bl = BufferListStream()
+
+// equivalent to:
+
+const { BufferListStream } = require('bl')
+const bl = new BufferListStream()
+```
+
+N.B. For backwards compatibility reasons, `BufferListStream` is the **default** export when you `require('bl')`:
+
+```js
+const { BufferListStream } = require('bl')
+// equivalent to:
+const BufferListStream = require('bl')
+```
+
+--------------------------------------------------------
+
+## Contributors
+
+**bl** is brought to you by the following hackers:
+
+ * [Rod Vagg](https://github.com/rvagg)
+ * [Matteo Collina](https://github.com/mcollina)
+ * [Jarett Cruger](https://github.com/jcrugzz)
+
+<a name="license"></a>
+## License & copyright
+
+Copyright (c) 2013-2019 bl contributors (listed above).
+
+bl is licensed under the MIT license. All rights not explicitly granted in the MIT license are reserved. See the included LICENSE.md file for more details.
diff --git a/server/node_modules/bl/bl.js b/server/node_modules/bl/bl.js
new file mode 100644
index 0000000..40228f8
--- /dev/null
+++ b/server/node_modules/bl/bl.js
@@ -0,0 +1,84 @@
+'use strict'
+
+const DuplexStream = require('readable-stream').Duplex
+const inherits = require('inherits')
+const BufferList = require('./BufferList')
+
+function BufferListStream (callback) {
+  if (!(this instanceof BufferListStream)) {
+    return new BufferListStream(callback)
+  }
+
+  if (typeof callback === 'function') {
+    this._callback = callback
+
+    const piper = function piper (err) {
+      if (this._callback) {
+        this._callback(err)
+        this._callback = null
+      }
+    }.bind(this)
+
+    this.on('pipe', function onPipe (src) {
+      src.on('error', piper)
+    })
+    this.on('unpipe', function onUnpipe (src) {
+      src.removeListener('error', piper)
+    })
+
+    callback = null
+  }
+
+  BufferList._init.call(this, callback)
+  DuplexStream.call(this)
+}
+
+inherits(BufferListStream, DuplexStream)
+Object.assign(BufferListStream.prototype, BufferList.prototype)
+
+BufferListStream.prototype._new = function _new (callback) {
+  return new BufferListStream(callback)
+}
+
+BufferListStream.prototype._write = function _write (buf, encoding, callback) {
+  this._appendBuffer(buf)
+
+  if (typeof callback === 'function') {
+    callback()
+  }
+}
+
+BufferListStream.prototype._read = function _read (size) {
+  if (!this.length) {
+    return this.push(null)
+  }
+
+  size = Math.min(size, this.length)
+  this.push(this.slice(0, size))
+  this.consume(size)
+}
+
+BufferListStream.prototype.end = function end (chunk) {
+  DuplexStream.prototype.end.call(this, chunk)
+
+  if (this._callback) {
+    this._callback(null, this.slice())
+    this._callback = null
+  }
+}
+
+BufferListStream.prototype._destroy = function _destroy (err, cb) {
+  this._bufs.length = 0
+  this.length = 0
+  cb(err)
+}
+
+BufferListStream.prototype._isBufferList = function _isBufferList (b) {
+  return b instanceof BufferListStream || b instanceof BufferList || BufferListStream.isBufferList(b)
+}
+
+BufferListStream.isBufferList = BufferList.isBufferList
+
+module.exports = BufferListStream
+module.exports.BufferListStream = BufferListStream
+module.exports.BufferList = BufferList
diff --git a/server/node_modules/bl/node_modules/readable-stream/CONTRIBUTING.md b/server/node_modules/bl/node_modules/readable-stream/CONTRIBUTING.md
new file mode 100644
index 0000000..f478d58
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/CONTRIBUTING.md
@@ -0,0 +1,38 @@
+# Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+* (a) The contribution was created in whole or in part by me and I
+  have the right to submit it under the open source license
+  indicated in the file; or
+
+* (b) The contribution is based upon previous work that, to the best
+  of my knowledge, is covered under an appropriate open source
+  license and I have the right under that license to submit that
+  work with modifications, whether created in whole or in part
+  by me, under the same open source license (unless I am
+  permitted to submit under a different license), as indicated
+  in the file; or
+
+* (c) The contribution was provided directly to me by some other
+  person who certified (a), (b) or (c) and I have not modified
+  it.
+
+* (d) I understand and agree that this project and the contribution
+  are public and that a record of the contribution (including all
+  personal information I submit with it, including my sign-off) is
+  maintained indefinitely and may be redistributed consistent with
+  this project or the open source license(s) involved.
+
+## Moderation Policy
+
+The [Node.js Moderation Policy] applies to this WG.
+
+## Code of Conduct
+
+The [Node.js Code of Conduct][] applies to this WG.
+
+[Node.js Code of Conduct]:
+https://github.com/nodejs/node/blob/master/CODE_OF_CONDUCT.md
+[Node.js Moderation Policy]:
+https://github.com/nodejs/TSC/blob/master/Moderation-Policy.md
diff --git a/server/node_modules/bl/node_modules/readable-stream/GOVERNANCE.md b/server/node_modules/bl/node_modules/readable-stream/GOVERNANCE.md
new file mode 100644
index 0000000..16ffb93
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/GOVERNANCE.md
@@ -0,0 +1,136 @@
+### Streams Working Group
+
+The Node.js Streams is jointly governed by a Working Group
+(WG)
+that is responsible for high-level guidance of the project.
+
+The WG has final authority over this project including:
+
+* Technical direction
+* Project governance and process (including this policy)
+* Contribution policy
+* GitHub repository hosting
+* Conduct guidelines
+* Maintaining the list of additional Collaborators
+
+For the current list of WG members, see the project
+[README.md](./README.md#current-project-team-members).
+
+### Collaborators
+
+The readable-stream GitHub repository is
+maintained by the WG and additional Collaborators who are added by the
+WG on an ongoing basis.
+
+Individuals making significant and valuable contributions are made
+Collaborators and given commit-access to the project. These
+individuals are identified by the WG and their addition as
+Collaborators is discussed during the WG meeting.
+
+_Note:_ If you make a significant contribution and are not considered
+for commit-access log an issue or contact a WG member directly and it
+will be brought up in the next WG meeting.
+
+Modifications of the contents of the readable-stream repository are
+made on
+a collaborative basis. Anybody with a GitHub account may propose a
+modification via pull request and it will be considered by the project
+Collaborators. All pull requests must be reviewed and accepted by a
+Collaborator with sufficient expertise who is able to take full
+responsibility for the change. In the case of pull requests proposed
+by an existing Collaborator, an additional Collaborator is required
+for sign-off. Consensus should be sought if additional Collaborators
+participate and there is disagreement around a particular
+modification. See _Consensus Seeking Process_ below for further detail
+on the consensus model used for governance.
+
+Collaborators may opt to elevate significant or controversial
+modifications, or modifications that have not found consensus to the
+WG for discussion by assigning the ***WG-agenda*** tag to a pull
+request or issue. The WG should serve as the final arbiter where
+required.
+
+For the current list of Collaborators, see the project
+[README.md](./README.md#members).
+
+### WG Membership
+
+WG seats are not time-limited.  There is no fixed size of the WG.
+However, the expected target is between 6 and 12, to ensure adequate
+coverage of important areas of expertise, balanced with the ability to
+make decisions efficiently.
+
+There is no specific set of requirements or qualifications for WG
+membership beyond these rules.
+
+The WG may add additional members to the WG by unanimous consensus.
+
+A WG member may be removed from the WG by voluntary resignation, or by
+unanimous consensus of all other WG members.
+
+Changes to WG membership should be posted in the agenda, and may be
+suggested as any other agenda item (see "WG Meetings" below).
+
+If an addition or removal is proposed during a meeting, and the full
+WG is not in attendance to participate, then the addition or removal
+is added to the agenda for the subsequent meeting.  This is to ensure
+that all members are given the opportunity to participate in all
+membership decisions.  If a WG member is unable to attend a meeting
+where a planned membership decision is being made, then their consent
+is assumed.
+
+No more than 1/3 of the WG members may be affiliated with the same
+employer.  If removal or resignation of a WG member, or a change of
+employment by a WG member, creates a situation where more than 1/3 of
+the WG membership shares an employer, then the situation must be
+immediately remedied by the resignation or removal of one or more WG
+members affiliated with the over-represented employer(s).
+
+### WG Meetings
+
+The WG meets occasionally on a Google Hangout On Air. A designated moderator
+approved by the WG runs the meeting. Each meeting should be
+published to YouTube.
+
+Items are added to the WG agenda that are considered contentious or
+are modifications of governance, contribution policy, WG membership,
+or release process.
+
+The intention of the agenda is not to approve or review all patches;
+that should happen continuously on GitHub and be handled by the larger
+group of Collaborators.
+
+Any community member or contributor can ask that something be added to
+the next meeting's agenda by logging a GitHub Issue. Any Collaborator,
+WG member or the moderator can add the item to the agenda by adding
+the ***WG-agenda*** tag to the issue.
+
+Prior to each WG meeting the moderator will share the Agenda with
+members of the WG. WG members can add any items they like to the
+agenda at the beginning of each meeting. The moderator and the WG
+cannot veto or remove items.
+
+The WG may invite persons or representatives from certain projects to
+participate in a non-voting capacity.
+
+The moderator is responsible for summarizing the discussion of each
+agenda item and sends it as a pull request after the meeting.
+
+### Consensus Seeking Process
+
+The WG follows a
+[Consensus
+Seeking](http://en.wikipedia.org/wiki/Consensus-seeking_decision-making)
+decision-making model.
+
+When an agenda item has appeared to reach a consensus the moderator
+will ask "Does anyone object?" as a final call for dissent from the
+consensus.
+
+If an agenda item cannot reach a consensus a WG member can call for
+either a closing vote or a vote to table the issue to the next
+meeting. The call for a vote must be seconded by a majority of the WG
+or else the discussion will continue. Simple majority wins.
+
+Note that changes to WG membership require a majority consensus.  See
+"WG Membership" above.
diff --git a/server/node_modules/bl/node_modules/readable-stream/LICENSE b/server/node_modules/bl/node_modules/readable-stream/LICENSE
new file mode 100644
index 0000000..2873b3b
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/LICENSE
@@ -0,0 +1,47 @@
+Node.js is licensed for use as follows:
+
+"""
+Copyright Node.js contributors. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
+
+This license applies to parts of Node.js originating from the
+https://github.com/joyent/node repository:
+
+"""
+Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
diff --git a/server/node_modules/bl/node_modules/readable-stream/README.md b/server/node_modules/bl/node_modules/readable-stream/README.md
new file mode 100644
index 0000000..19117c1
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/README.md
@@ -0,0 +1,106 @@
+# readable-stream
+
+***Node.js core streams for userland*** [![Build Status](https://travis-ci.com/nodejs/readable-stream.svg?branch=master)](https://travis-ci.com/nodejs/readable-stream)
+
+
+[![NPM](https://nodei.co/npm/readable-stream.png?downloads=true&downloadRank=true)](https://nodei.co/npm/readable-stream/)
+[![NPM](https://nodei.co/npm-dl/readable-stream.png?&months=6&height=3)](https://nodei.co/npm/readable-stream/)
+
+
+[![Sauce Test Status](https://saucelabs.com/browser-matrix/readabe-stream.svg)](https://saucelabs.com/u/readabe-stream)
+
+```bash
+npm install --save readable-stream
+```
+
+This package is a mirror of the streams implementations in Node.js.
+
+Full documentation may be found on the [Node.js website](https://nodejs.org/dist/v10.18.1/docs/api/stream.html).
+
+If you want to guarantee a stable streams base, regardless of what version of
+Node you, or the users of your libraries are using, use **readable-stream** *only* and avoid the *"stream"* module in Node-core, for background see [this blogpost](http://r.va.gg/2014/06/why-i-dont-use-nodes-core-stream-module.html).
+
+As of version 2.0.0 **readable-stream** uses semantic versioning.
+
+## Version 3.x.x
+
+v3.x.x of `readable-stream` is a cut from Node 10. This version supports Node 6, 8, and 10, as well as evergreen browsers, IE 11 and latest Safari. The breaking changes introduced by v3 are composed by the combined breaking changes in [Node v9](https://nodejs.org/en/blog/release/v9.0.0/) and [Node v10](https://nodejs.org/en/blog/release/v10.0.0/), as follows:
+
+1. Error codes: https://github.com/nodejs/node/pull/13310,
+   https://github.com/nodejs/node/pull/13291,
+   https://github.com/nodejs/node/pull/16589,
+   https://github.com/nodejs/node/pull/15042,
+   https://github.com/nodejs/node/pull/15665,
+   https://github.com/nodejs/readable-stream/pull/344
+2. 'readable' have precedence over flowing
+   https://github.com/nodejs/node/pull/18994
+3. make virtual methods errors consistent
+   https://github.com/nodejs/node/pull/18813
+4. updated streams error handling
+   https://github.com/nodejs/node/pull/18438
+5. writable.end should return this.
+   https://github.com/nodejs/node/pull/18780
+6. readable continues to read when push('')
+   https://github.com/nodejs/node/pull/18211
+7. add custom inspect to BufferList
+   https://github.com/nodejs/node/pull/17907
+8. always defer 'readable' with nextTick
+   https://github.com/nodejs/node/pull/17979
+
+## Version 2.x.x
+v2.x.x of `readable-stream` is a cut of the stream module from Node 8 (there have been no semver-major changes from Node 4 to 8). This version supports all Node.js versions from 0.8, as well as evergreen browsers and IE 10 & 11.
+
+### Big Thanks
+
+Cross-browser Testing Platform and Open Source <3 Provided by [Sauce Labs][sauce]
+
+# Usage
+
+You can swap your `require('stream')` with `require('readable-stream')`
+without any changes, if you are just using one of the main classes and
+functions.
+
+```js
+const {
+  Readable,
+  Writable,
+  Transform,
+  Duplex,
+  pipeline,
+  finished
+} = require('readable-stream')
+````
+
+Note that `require('stream')` will return `Stream`, while
+`require('readable-stream')` will return `Readable`. We discourage using
+whatever is exported directly, but rather use one of the properties as
+shown in the example above.
+
+# Streams Working Group
+
+`readable-stream` is maintained by the Streams Working Group, which
+oversees the development and maintenance of the Streams API within
+Node.js. The responsibilities of the Streams Working Group include:
+
+* Addressing stream issues on the Node.js issue tracker.
+* Authoring and editing stream documentation within the Node.js project.
+* Reviewing changes to stream subclasses within the Node.js project.
+* Redirecting changes to streams from the Node.js project to this
+  project.
+* Assisting in the implementation of stream providers within Node.js.
+* Recommending versions of `readable-stream` to be included in Node.js.
+* Messaging about the future of streams to give the community advance
+  notice of changes.
+
+<a name="members"></a>
+## Team Members
+
+* **Calvin Metcalf** ([@calvinmetcalf](https://github.com/calvinmetcalf)) <calvin.metcalf@gmail.com>
+  - Release GPG key: F3EF5F62A87FC27A22E643F714CE4FF5015AA242
+* **Mathias Buus** ([@mafintosh](https://github.com/mafintosh)) <mathiasbuus@gmail.com>
+* **Matteo Collina** ([@mcollina](https://github.com/mcollina)) <matteo.collina@gmail.com>
+  - Release GPG key: 3ABC01543F22DD2239285CDD818674489FBC127E
+* **Irina Shestak** ([@lrlna](https://github.com/lrlna)) <shestak.irina@gmail.com>
+* **Yoshua Wyuts** ([@yoshuawuyts](https://github.com/yoshuawuyts)) <yoshuawuyts@gmail.com>
+
+[sauce]: https://saucelabs.com
diff --git a/server/node_modules/bl/node_modules/readable-stream/errors-browser.js b/server/node_modules/bl/node_modules/readable-stream/errors-browser.js
new file mode 100644
index 0000000..fb8e73e
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/errors-browser.js
@@ -0,0 +1,127 @@
+'use strict';
+
+function _inheritsLoose(subClass, superClass) { subClass.prototype = Object.create(superClass.prototype); subClass.prototype.constructor = subClass; subClass.__proto__ = superClass; }
+
+var codes = {};
+
+function createErrorType(code, message, Base) {
+  if (!Base) {
+    Base = Error;
+  }
+
+  function getMessage(arg1, arg2, arg3) {
+    if (typeof message === 'string') {
+      return message;
+    } else {
+      return message(arg1, arg2, arg3);
+    }
+  }
+
+  var NodeError =
+  /*#__PURE__*/
+  function (_Base) {
+    _inheritsLoose(NodeError, _Base);
+
+    function NodeError(arg1, arg2, arg3) {
+      return _Base.call(this, getMessage(arg1, arg2, arg3)) || this;
+    }
+
+    return NodeError;
+  }(Base);
+
+  NodeError.prototype.name = Base.name;
+  NodeError.prototype.code = code;
+  codes[code] = NodeError;
+} // https://github.com/nodejs/node/blob/v10.8.0/lib/internal/errors.js
+
+
+function oneOf(expected, thing) {
+  if (Array.isArray(expected)) {
+    var len = expected.length;
+    expected = expected.map(function (i) {
+      return String(i);
+    });
+
+    if (len > 2) {
+      return "one of ".concat(thing, " ").concat(expected.slice(0, len - 1).join(', '), ", or ") + expected[len - 1];
+    } else if (len === 2) {
+      return "one of ".concat(thing, " ").concat(expected[0], " or ").concat(expected[1]);
+    } else {
+      return "of ".concat(thing, " ").concat(expected[0]);
+    }
+  } else {
+    return "of ".concat(thing, " ").concat(String(expected));
+  }
+} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
+
+
+function startsWith(str, search, pos) {
+  return str.substr(!pos || pos < 0 ? 0 : +pos, search.length) === search;
+} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith
+
+
+function endsWith(str, search, this_len) {
+  if (this_len === undefined || this_len > str.length) {
+    this_len = str.length;
+  }
+
+  return str.substring(this_len - search.length, this_len) === search;
+} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes
+
+
+function includes(str, search, start) {
+  if (typeof start !== 'number') {
+    start = 0;
+  }
+
+  if (start + search.length > str.length) {
+    return false;
+  } else {
+    return str.indexOf(search, start) !== -1;
+  }
+}
+
+createErrorType('ERR_INVALID_OPT_VALUE', function (name, value) {
+  return 'The value "' + value + '" is invalid for option "' + name + '"';
+}, TypeError);
+createErrorType('ERR_INVALID_ARG_TYPE', function (name, expected, actual) {
+  // determiner: 'must be' or 'must not be'
+  var determiner;
+
+  if (typeof expected === 'string' && startsWith(expected, 'not ')) {
+    determiner = 'must not be';
+    expected = expected.replace(/^not /, '');
+  } else {
+    determiner = 'must be';
+  }
+
+  var msg;
+
+  if (endsWith(name, ' argument')) {
+    // For cases like 'first argument'
+    msg = "The ".concat(name, " ").concat(determiner, " ").concat(oneOf(expected, 'type'));
+  } else {
+    var type = includes(name, '.') ? 'property' : 'argument';
+    msg = "The \"".concat(name, "\" ").concat(type, " ").concat(determiner, " ").concat(oneOf(expected, 'type'));
+  }
+
+  msg += ". Received type ".concat(typeof actual);
+  return msg;
+}, TypeError);
+createErrorType('ERR_STREAM_PUSH_AFTER_EOF', 'stream.push() after EOF');
+createErrorType('ERR_METHOD_NOT_IMPLEMENTED', function (name) {
+  return 'The ' + name + ' method is not implemented';
+});
+createErrorType('ERR_STREAM_PREMATURE_CLOSE', 'Premature close');
+createErrorType('ERR_STREAM_DESTROYED', function (name) {
+  return 'Cannot call ' + name + ' after a stream was destroyed';
+});
+createErrorType('ERR_MULTIPLE_CALLBACK', 'Callback called multiple times');
+createErrorType('ERR_STREAM_CANNOT_PIPE', 'Cannot pipe, not readable');
+createErrorType('ERR_STREAM_WRITE_AFTER_END', 'write after end');
+createErrorType('ERR_STREAM_NULL_VALUES', 'May not write null values to stream', TypeError);
+createErrorType('ERR_UNKNOWN_ENCODING', function (arg) {
+  return 'Unknown encoding: ' + arg;
+}, TypeError);
+createErrorType('ERR_STREAM_UNSHIFT_AFTER_END_EVENT', 'stream.unshift() after end event');
+module.exports.codes = codes;
diff --git a/server/node_modules/bl/node_modules/readable-stream/errors.js b/server/node_modules/bl/node_modules/readable-stream/errors.js
new file mode 100644
index 0000000..8471526
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/errors.js
@@ -0,0 +1,116 @@
+'use strict';
+
+const codes = {};
+
+function createErrorType(code, message, Base) {
+  if (!Base) {
+    Base = Error
+  }
+
+  function getMessage (arg1, arg2, arg3) {
+    if (typeof message === 'string') {
+      return message
+    } else {
+      return message(arg1, arg2, arg3)
+    }
+  }
+
+  class NodeError extends Base {
+    constructor (arg1, arg2, arg3) {
+      super(getMessage(arg1, arg2, arg3));
+    }
+  }
+
+  NodeError.prototype.name = Base.name;
+  NodeError.prototype.code = code;
+
+  codes[code] = NodeError;
+}
+
+// https://github.com/nodejs/node/blob/v10.8.0/lib/internal/errors.js
+function oneOf(expected, thing) {
+  if (Array.isArray(expected)) {
+    const len = expected.length;
+    expected = expected.map((i) => String(i));
+    if (len > 2) {
+      return `one of ${thing} ${expected.slice(0, len - 1).join(', ')}, or ` +
+             expected[len - 1];
+    } else if (len === 2) {
+      return `one of ${thing} ${expected[0]} or ${expected[1]}`;
+    } else {
+      return `of ${thing} ${expected[0]}`;
+    }
+  } else {
+    return `of ${thing} ${String(expected)}`;
+  }
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
+function startsWith(str, search, pos) {
+	return str.substr(!pos || pos < 0 ? 0 : +pos, search.length) === search;
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith
+function endsWith(str, search, this_len) {
+	if (this_len === undefined || this_len > str.length) {
+		this_len = str.length;
+	}
+	return str.substring(this_len - search.length, this_len) === search;
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes
+function includes(str, search, start) {
+  if (typeof start !== 'number') {
+    start = 0;
+  }
+
+  if (start + search.length > str.length) {
+    return false;
+  } else {
+    return str.indexOf(search, start) !== -1;
+  }
+}
+
+createErrorType('ERR_INVALID_OPT_VALUE', function (name, value) {
+  return 'The value "' + value + '" is invalid for option "' + name + '"'
+}, TypeError);
+createErrorType('ERR_INVALID_ARG_TYPE', function (name, expected, actual) {
+  // determiner: 'must be' or 'must not be'
+  let determiner;
+  if (typeof expected === 'string' && startsWith(expected, 'not ')) {
+    determiner = 'must not be';
+    expected = expected.replace(/^not /, '');
+  } else {
+    determiner = 'must be';
+  }
+
+  let msg;
+  if (endsWith(name, ' argument')) {
+    // For cases like 'first argument'
+    msg = `The ${name} ${determiner} ${oneOf(expected, 'type')}`;
+  } else {
+    const type = includes(name, '.') ? 'property' : 'argument';
+    msg = `The "${name}" ${type} ${determiner} ${oneOf(expected, 'type')}`;
+  }
+
+  msg += `. Received type ${typeof actual}`;
+  return msg;
+}, TypeError);
+createErrorType('ERR_STREAM_PUSH_AFTER_EOF', 'stream.push() after EOF');
+createErrorType('ERR_METHOD_NOT_IMPLEMENTED', function (name) {
+  return 'The ' + name + ' method is not implemented'
+});
+createErrorType('ERR_STREAM_PREMATURE_CLOSE', 'Premature close');
+createErrorType('ERR_STREAM_DESTROYED', function (name) {
+  return 'Cannot call ' + name + ' after a stream was destroyed';
+});
+createErrorType('ERR_MULTIPLE_CALLBACK', 'Callback called multiple times');
+createErrorType('ERR_STREAM_CANNOT_PIPE', 'Cannot pipe, not readable');
+createErrorType('ERR_STREAM_WRITE_AFTER_END', 'write after end');
+createErrorType('ERR_STREAM_NULL_VALUES', 'May not write null values to stream', TypeError);
+createErrorType('ERR_UNKNOWN_ENCODING', function (arg) {
+  return 'Unknown encoding: ' + arg
+}, TypeError);
+createErrorType('ERR_STREAM_UNSHIFT_AFTER_END_EVENT', 'stream.unshift() after end event');
+
+module.exports.codes = codes;
diff --git a/server/node_modules/bl/node_modules/readable-stream/experimentalWarning.js b/server/node_modules/bl/node_modules/readable-stream/experimentalWarning.js
new file mode 100644
index 0000000..78e8414
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/experimentalWarning.js
@@ -0,0 +1,17 @@
+'use strict'
+
+var experimentalWarnings = new Set();
+
+function emitExperimentalWarning(feature) {
+  if (experimentalWarnings.has(feature)) return;
+  var msg = feature + ' is an experimental feature. This feature could ' +
+       'change at any time';
+  experimentalWarnings.add(feature);
+  process.emitWarning(msg, 'ExperimentalWarning');
+}
+
+function noop() {}
+
+module.exports.emitExperimentalWarning = process.emitWarning
+  ? emitExperimentalWarning
+  : noop;
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/_stream_duplex.js b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_duplex.js
new file mode 100644
index 0000000..19abfa6
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_duplex.js
@@ -0,0 +1,126 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a duplex stream is just a stream that is both readable and writable.
+// Since JS doesn't have multiple prototypal inheritance, this class
+// prototypally inherits from Readable, and then parasitically from
+// Writable.
+
+'use strict';
+
+/*<replacement>*/
+var objectKeys = Object.keys || function (obj) {
+  var keys = [];
+  for (var key in obj) keys.push(key);
+  return keys;
+};
+/*</replacement>*/
+
+module.exports = Duplex;
+var Readable = require('./_stream_readable');
+var Writable = require('./_stream_writable');
+require('inherits')(Duplex, Readable);
+{
+  // Allow the keys array to be GC'ed.
+  var keys = objectKeys(Writable.prototype);
+  for (var v = 0; v < keys.length; v++) {
+    var method = keys[v];
+    if (!Duplex.prototype[method]) Duplex.prototype[method] = Writable.prototype[method];
+  }
+}
+function Duplex(options) {
+  if (!(this instanceof Duplex)) return new Duplex(options);
+  Readable.call(this, options);
+  Writable.call(this, options);
+  this.allowHalfOpen = true;
+  if (options) {
+    if (options.readable === false) this.readable = false;
+    if (options.writable === false) this.writable = false;
+    if (options.allowHalfOpen === false) {
+      this.allowHalfOpen = false;
+      this.once('end', onend);
+    }
+  }
+}
+Object.defineProperty(Duplex.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.highWaterMark;
+  }
+});
+Object.defineProperty(Duplex.prototype, 'writableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState && this._writableState.getBuffer();
+  }
+});
+Object.defineProperty(Duplex.prototype, 'writableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.length;
+  }
+});
+
+// the no-half-open enforcer
+function onend() {
+  // If the writable side ended, then we're ok.
+  if (this._writableState.ended) return;
+
+  // no more data can be written.
+  // But allow more writes to happen in this tick.
+  process.nextTick(onEndNT, this);
+}
+function onEndNT(self) {
+  self.end();
+}
+Object.defineProperty(Duplex.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed && this._writableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+    this._writableState.destroyed = value;
+  }
+});
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/_stream_passthrough.js b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_passthrough.js
new file mode 100644
index 0000000..24a6bdd
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_passthrough.js
@@ -0,0 +1,37 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a passthrough stream.
+// basically just the most minimal sort of Transform stream.
+// Every written chunk gets output as-is.
+
+'use strict';
+
+module.exports = PassThrough;
+var Transform = require('./_stream_transform');
+require('inherits')(PassThrough, Transform);
+function PassThrough(options) {
+  if (!(this instanceof PassThrough)) return new PassThrough(options);
+  Transform.call(this, options);
+}
+PassThrough.prototype._transform = function (chunk, encoding, cb) {
+  cb(null, chunk);
+};
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/_stream_readable.js b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_readable.js
new file mode 100644
index 0000000..df1f608
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_readable.js
@@ -0,0 +1,1027 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+
+module.exports = Readable;
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Readable.ReadableState = ReadableState;
+
+/*<replacement>*/
+var EE = require('events').EventEmitter;
+var EElistenerCount = function EElistenerCount(emitter, type) {
+  return emitter.listeners(type).length;
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+var Buffer = require('buffer').Buffer;
+var OurUint8Array = (typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : typeof self !== 'undefined' ? self : {}).Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+
+/*<replacement>*/
+var debugUtil = require('util');
+var debug;
+if (debugUtil && debugUtil.debuglog) {
+  debug = debugUtil.debuglog('stream');
+} else {
+  debug = function debug() {};
+}
+/*</replacement>*/
+
+var BufferList = require('./internal/streams/buffer_list');
+var destroyImpl = require('./internal/streams/destroy');
+var _require = require('./internal/streams/state'),
+  getHighWaterMark = _require.getHighWaterMark;
+var _require$codes = require('../errors').codes,
+  ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
+  ERR_STREAM_PUSH_AFTER_EOF = _require$codes.ERR_STREAM_PUSH_AFTER_EOF,
+  ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_STREAM_UNSHIFT_AFTER_END_EVENT = _require$codes.ERR_STREAM_UNSHIFT_AFTER_END_EVENT;
+
+// Lazy loaded to improve the startup performance.
+var StringDecoder;
+var createReadableStreamAsyncIterator;
+var from;
+require('inherits')(Readable, Stream);
+var errorOrDestroy = destroyImpl.errorOrDestroy;
+var kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
+function prependListener(emitter, event, fn) {
+  // Sadly this is not cacheable as some libraries bundle their own
+  // event emitter implementation with them.
+  if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn);
+
+  // This is a hack to make sure that our error handler is attached before any
+  // userland ones.  NEVER DO THIS. This is here only because this code needs
+  // to continue to work with older versions of Node.js that do not include
+  // the prependListener() method. The goal is to eventually remove this hack.
+  if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (Array.isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
+}
+function ReadableState(options, stream, isDuplex) {
+  Duplex = Duplex || require('./_stream_duplex');
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream.
+  // These options can be provided separately as readableXXX and writableXXX.
+  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex;
+
+  // object stream flag. Used to make read(n) ignore n and to
+  // make all the buffer merging and length checks go away
+  this.objectMode = !!options.objectMode;
+  if (isDuplex) this.objectMode = this.objectMode || !!options.readableObjectMode;
+
+  // the point at which it stops calling _read() to fill the buffer
+  // Note: 0 is a valid value, means "don't call _read preemptively ever"
+  this.highWaterMark = getHighWaterMark(this, options, 'readableHighWaterMark', isDuplex);
+
+  // A linked list is used to store data chunks instead of an array because the
+  // linked list can remove elements from the beginning faster than
+  // array.shift()
+  this.buffer = new BufferList();
+  this.length = 0;
+  this.pipes = null;
+  this.pipesCount = 0;
+  this.flowing = null;
+  this.ended = false;
+  this.endEmitted = false;
+  this.reading = false;
+
+  // a flag to be able to tell if the event 'readable'/'data' is emitted
+  // immediately, or on a later tick.  We set this to true at first, because
+  // any actions that shouldn't happen until "later" should generally also
+  // not happen before the first read call.
+  this.sync = true;
+
+  // whenever we return null, then we set a flag to say
+  // that we're awaiting a 'readable' event emission.
+  this.needReadable = false;
+  this.emittedReadable = false;
+  this.readableListening = false;
+  this.resumeScheduled = false;
+  this.paused = true;
+
+  // Should close be emitted on destroy. Defaults to true.
+  this.emitClose = options.emitClose !== false;
+
+  // Should .destroy() be called after 'end' (and potentially 'finish')
+  this.autoDestroy = !!options.autoDestroy;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // the number of writers that are awaiting a drain event in .pipe()s
+  this.awaitDrain = 0;
+
+  // if true, a maybeReadMore has been scheduled
+  this.readingMore = false;
+  this.decoder = null;
+  this.encoding = null;
+  if (options.encoding) {
+    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+    this.decoder = new StringDecoder(options.encoding);
+    this.encoding = options.encoding;
+  }
+}
+function Readable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+  if (!(this instanceof Readable)) return new Readable(options);
+
+  // Checking for a Stream.Duplex instance is faster here instead of inside
+  // the ReadableState constructor, at least with V8 6.5
+  var isDuplex = this instanceof Duplex;
+  this._readableState = new ReadableState(options, this, isDuplex);
+
+  // legacy
+  this.readable = true;
+  if (options) {
+    if (typeof options.read === 'function') this._read = options.read;
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+  }
+  Stream.call(this);
+}
+Object.defineProperty(Readable.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._readableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._readableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+  }
+});
+Readable.prototype.destroy = destroyImpl.destroy;
+Readable.prototype._undestroy = destroyImpl.undestroy;
+Readable.prototype._destroy = function (err, cb) {
+  cb(err);
+};
+
+// Manually shove something into the read() buffer.
+// This returns true if the highWaterMark has not been hit yet,
+// similar to how Writable.write() returns true if you should
+// write() some more.
+Readable.prototype.push = function (chunk, encoding) {
+  var state = this._readableState;
+  var skipChunkCheck;
+  if (!state.objectMode) {
+    if (typeof chunk === 'string') {
+      encoding = encoding || state.defaultEncoding;
+      if (encoding !== state.encoding) {
+        chunk = Buffer.from(chunk, encoding);
+        encoding = '';
+      }
+      skipChunkCheck = true;
+    }
+  } else {
+    skipChunkCheck = true;
+  }
+  return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
+};
+
+// Unshift should *always* be something directly out of read()
+Readable.prototype.unshift = function (chunk) {
+  return readableAddChunk(this, chunk, null, true, false);
+};
+function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
+  debug('readableAddChunk', chunk);
+  var state = stream._readableState;
+  if (chunk === null) {
+    state.reading = false;
+    onEofChunk(stream, state);
+  } else {
+    var er;
+    if (!skipChunkCheck) er = chunkInvalid(state, chunk);
+    if (er) {
+      errorOrDestroy(stream, er);
+    } else if (state.objectMode || chunk && chunk.length > 0) {
+      if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
+        chunk = _uint8ArrayToBuffer(chunk);
+      }
+      if (addToFront) {
+        if (state.endEmitted) errorOrDestroy(stream, new ERR_STREAM_UNSHIFT_AFTER_END_EVENT());else addChunk(stream, state, chunk, true);
+      } else if (state.ended) {
+        errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
+      } else if (state.destroyed) {
+        return false;
+      } else {
+        state.reading = false;
+        if (state.decoder && !encoding) {
+          chunk = state.decoder.write(chunk);
+          if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
+        } else {
+          addChunk(stream, state, chunk, false);
+        }
+      }
+    } else if (!addToFront) {
+      state.reading = false;
+      maybeReadMore(stream, state);
+    }
+  }
+
+  // We can push more data if we are below the highWaterMark.
+  // Also, if we have no data yet, we can stand some more bytes.
+  // This is to work around cases where hwm=0, such as the repl.
+  return !state.ended && (state.length < state.highWaterMark || state.length === 0);
+}
+function addChunk(stream, state, chunk, addToFront) {
+  if (state.flowing && state.length === 0 && !state.sync) {
+    state.awaitDrain = 0;
+    stream.emit('data', chunk);
+  } else {
+    // update the buffer info.
+    state.length += state.objectMode ? 1 : chunk.length;
+    if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);
+    if (state.needReadable) emitReadable(stream);
+  }
+  maybeReadMore(stream, state);
+}
+function chunkInvalid(state, chunk) {
+  var er;
+  if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
+    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer', 'Uint8Array'], chunk);
+  }
+  return er;
+}
+Readable.prototype.isPaused = function () {
+  return this._readableState.flowing === false;
+};
+
+// backwards compatibility.
+Readable.prototype.setEncoding = function (enc) {
+  if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+  var decoder = new StringDecoder(enc);
+  this._readableState.decoder = decoder;
+  // If setEncoding(null), decoder.encoding equals utf8
+  this._readableState.encoding = this._readableState.decoder.encoding;
+
+  // Iterate over current buffer to convert already stored Buffers:
+  var p = this._readableState.buffer.head;
+  var content = '';
+  while (p !== null) {
+    content += decoder.write(p.data);
+    p = p.next;
+  }
+  this._readableState.buffer.clear();
+  if (content !== '') this._readableState.buffer.push(content);
+  this._readableState.length = content.length;
+  return this;
+};
+
+// Don't raise the hwm > 1GB
+var MAX_HWM = 0x40000000;
+function computeNewHighWaterMark(n) {
+  if (n >= MAX_HWM) {
+    // TODO(ronag): Throw ERR_VALUE_OUT_OF_RANGE.
+    n = MAX_HWM;
+  } else {
+    // Get the next highest power of 2 to prevent increasing hwm excessively in
+    // tiny amounts
+    n--;
+    n |= n >>> 1;
+    n |= n >>> 2;
+    n |= n >>> 4;
+    n |= n >>> 8;
+    n |= n >>> 16;
+    n++;
+  }
+  return n;
+}
+
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function howMuchToRead(n, state) {
+  if (n <= 0 || state.length === 0 && state.ended) return 0;
+  if (state.objectMode) return 1;
+  if (n !== n) {
+    // Only flow one buffer at a time
+    if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
+  }
+  // If we're asking for more than the current hwm, then raise the hwm.
+  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
+  if (n <= state.length) return n;
+  // Don't have enough
+  if (!state.ended) {
+    state.needReadable = true;
+    return 0;
+  }
+  return state.length;
+}
+
+// you can override either this method, or the async _read(n) below.
+Readable.prototype.read = function (n) {
+  debug('read', n);
+  n = parseInt(n, 10);
+  var state = this._readableState;
+  var nOrig = n;
+  if (n !== 0) state.emittedReadable = false;
+
+  // if we're doing read(0) to trigger a readable event, but we
+  // already have a bunch of data in the buffer, then just trigger
+  // the 'readable' event and move on.
+  if (n === 0 && state.needReadable && ((state.highWaterMark !== 0 ? state.length >= state.highWaterMark : state.length > 0) || state.ended)) {
+    debug('read: emitReadable', state.length, state.ended);
+    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
+    return null;
+  }
+  n = howMuchToRead(n, state);
+
+  // if we've ended, and we're now clear, then finish it up.
+  if (n === 0 && state.ended) {
+    if (state.length === 0) endReadable(this);
+    return null;
+  }
+
+  // All the actual chunk generation logic needs to be
+  // *below* the call to _read.  The reason is that in certain
+  // synthetic stream cases, such as passthrough streams, _read
+  // may be a completely synchronous operation which may change
+  // the state of the read buffer, providing enough data when
+  // before there was *not* enough.
+  //
+  // So, the steps are:
+  // 1. Figure out what the state of things will be after we do
+  // a read from the buffer.
+  //
+  // 2. If that resulting state will trigger a _read, then call _read.
+  // Note that this may be asynchronous, or synchronous.  Yes, it is
+  // deeply ugly to write APIs this way, but that still doesn't mean
+  // that the Readable class should behave improperly, as streams are
+  // designed to be sync/async agnostic.
+  // Take note if the _read call is sync or async (ie, if the read call
+  // has returned yet), so that we know whether or not it's safe to emit
+  // 'readable' etc.
+  //
+  // 3. Actually pull the requested chunks out of the buffer and return.
+
+  // if we need a readable event, then we need to do some reading.
+  var doRead = state.needReadable;
+  debug('need readable', doRead);
+
+  // if we currently have less than the highWaterMark, then also read some
+  if (state.length === 0 || state.length - n < state.highWaterMark) {
+    doRead = true;
+    debug('length less than watermark', doRead);
+  }
+
+  // however, if we've ended, then there's no point, and if we're already
+  // reading, then it's unnecessary.
+  if (state.ended || state.reading) {
+    doRead = false;
+    debug('reading or ended', doRead);
+  } else if (doRead) {
+    debug('do read');
+    state.reading = true;
+    state.sync = true;
+    // if the length is currently zero, then we *need* a readable event.
+    if (state.length === 0) state.needReadable = true;
+    // call internal read method
+    this._read(state.highWaterMark);
+    state.sync = false;
+    // If _read pushed data synchronously, then `reading` will be false,
+    // and we need to re-evaluate how much data we can return to the user.
+    if (!state.reading) n = howMuchToRead(nOrig, state);
+  }
+  var ret;
+  if (n > 0) ret = fromList(n, state);else ret = null;
+  if (ret === null) {
+    state.needReadable = state.length <= state.highWaterMark;
+    n = 0;
+  } else {
+    state.length -= n;
+    state.awaitDrain = 0;
+  }
+  if (state.length === 0) {
+    // If we have nothing in the buffer, then we want to know
+    // as soon as we *do* get something into the buffer.
+    if (!state.ended) state.needReadable = true;
+
+    // If we tried to read() past the EOF, then emit end on the next tick.
+    if (nOrig !== n && state.ended) endReadable(this);
+  }
+  if (ret !== null) this.emit('data', ret);
+  return ret;
+};
+function onEofChunk(stream, state) {
+  debug('onEofChunk');
+  if (state.ended) return;
+  if (state.decoder) {
+    var chunk = state.decoder.end();
+    if (chunk && chunk.length) {
+      state.buffer.push(chunk);
+      state.length += state.objectMode ? 1 : chunk.length;
+    }
+  }
+  state.ended = true;
+  if (state.sync) {
+    // if we are sync, wait until next tick to emit the data.
+    // Otherwise we risk emitting data in the flow()
+    // the readable code triggers during a read() call
+    emitReadable(stream);
+  } else {
+    // emit 'readable' now to make sure it gets picked up.
+    state.needReadable = false;
+    if (!state.emittedReadable) {
+      state.emittedReadable = true;
+      emitReadable_(stream);
+    }
+  }
+}
+
+// Don't emit readable right away in sync mode, because this can trigger
+// another read() call => stack overflow.  This way, it might trigger
+// a nextTick recursion warning, but that's not so bad.
+function emitReadable(stream) {
+  var state = stream._readableState;
+  debug('emitReadable', state.needReadable, state.emittedReadable);
+  state.needReadable = false;
+  if (!state.emittedReadable) {
+    debug('emitReadable', state.flowing);
+    state.emittedReadable = true;
+    process.nextTick(emitReadable_, stream);
+  }
+}
+function emitReadable_(stream) {
+  var state = stream._readableState;
+  debug('emitReadable_', state.destroyed, state.length, state.ended);
+  if (!state.destroyed && (state.length || state.ended)) {
+    stream.emit('readable');
+    state.emittedReadable = false;
+  }
+
+  // The stream needs another readable event if
+  // 1. It is not flowing, as the flow mechanism will take
+  //    care of it.
+  // 2. It is not ended.
+  // 3. It is below the highWaterMark, so we can schedule
+  //    another readable later.
+  state.needReadable = !state.flowing && !state.ended && state.length <= state.highWaterMark;
+  flow(stream);
+}
+
+// at this point, the user has presumably seen the 'readable' event,
+// and called read() to consume some data.  that may have triggered
+// in turn another _read(n) call, in which case reading = true if
+// it's in progress.
+// However, if we're not ended, or reading, and the length < hwm,
+// then go ahead and try to read some more preemptively.
+function maybeReadMore(stream, state) {
+  if (!state.readingMore) {
+    state.readingMore = true;
+    process.nextTick(maybeReadMore_, stream, state);
+  }
+}
+function maybeReadMore_(stream, state) {
+  // Attempt to read more data if we should.
+  //
+  // The conditions for reading more data are (one of):
+  // - Not enough data buffered (state.length < state.highWaterMark). The loop
+  //   is responsible for filling the buffer with enough data if such data
+  //   is available. If highWaterMark is 0 and we are not in the flowing mode
+  //   we should _not_ attempt to buffer any extra data. We'll get more data
+  //   when the stream consumer calls read() instead.
+  // - No data in the buffer, and the stream is in flowing mode. In this mode
+  //   the loop below is responsible for ensuring read() is called. Failing to
+  //   call read here would abort the flow and there's no other mechanism for
+  //   continuing the flow if the stream consumer has just subscribed to the
+  //   'data' event.
+  //
+  // In addition to the above conditions to keep reading data, the following
+  // conditions prevent the data from being read:
+  // - The stream has ended (state.ended).
+  // - There is already a pending 'read' operation (state.reading). This is a
+  //   case where the the stream has called the implementation defined _read()
+  //   method, but they are processing the call asynchronously and have _not_
+  //   called push() with new data. In this case we skip performing more
+  //   read()s. The execution ends in this method again after the _read() ends
+  //   up calling push() with more data.
+  while (!state.reading && !state.ended && (state.length < state.highWaterMark || state.flowing && state.length === 0)) {
+    var len = state.length;
+    debug('maybeReadMore read 0');
+    stream.read(0);
+    if (len === state.length)
+      // didn't get any data, stop spinning.
+      break;
+  }
+  state.readingMore = false;
+}
+
+// abstract method.  to be overridden in specific implementation classes.
+// call cb(er, data) where data is <= n in length.
+// for virtual (non-string, non-buffer) streams, "length" is somewhat
+// arbitrary, and perhaps not very meaningful.
+Readable.prototype._read = function (n) {
+  errorOrDestroy(this, new ERR_METHOD_NOT_IMPLEMENTED('_read()'));
+};
+Readable.prototype.pipe = function (dest, pipeOpts) {
+  var src = this;
+  var state = this._readableState;
+  switch (state.pipesCount) {
+    case 0:
+      state.pipes = dest;
+      break;
+    case 1:
+      state.pipes = [state.pipes, dest];
+      break;
+    default:
+      state.pipes.push(dest);
+      break;
+  }
+  state.pipesCount += 1;
+  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
+  var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;
+  var endFn = doEnd ? onend : unpipe;
+  if (state.endEmitted) process.nextTick(endFn);else src.once('end', endFn);
+  dest.on('unpipe', onunpipe);
+  function onunpipe(readable, unpipeInfo) {
+    debug('onunpipe');
+    if (readable === src) {
+      if (unpipeInfo && unpipeInfo.hasUnpiped === false) {
+        unpipeInfo.hasUnpiped = true;
+        cleanup();
+      }
+    }
+  }
+  function onend() {
+    debug('onend');
+    dest.end();
+  }
+
+  // when the dest drains, it reduces the awaitDrain counter
+  // on the source.  This would be more elegant with a .once()
+  // handler in flow(), but adding and removing repeatedly is
+  // too slow.
+  var ondrain = pipeOnDrain(src);
+  dest.on('drain', ondrain);
+  var cleanedUp = false;
+  function cleanup() {
+    debug('cleanup');
+    // cleanup event handlers once the pipe is broken
+    dest.removeListener('close', onclose);
+    dest.removeListener('finish', onfinish);
+    dest.removeListener('drain', ondrain);
+    dest.removeListener('error', onerror);
+    dest.removeListener('unpipe', onunpipe);
+    src.removeListener('end', onend);
+    src.removeListener('end', unpipe);
+    src.removeListener('data', ondata);
+    cleanedUp = true;
+
+    // if the reader is waiting for a drain event from this
+    // specific writer, then it would cause it to never start
+    // flowing again.
+    // So, if this is awaiting a drain, then we just call it now.
+    // If we don't know, then assume that we are waiting for one.
+    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
+  }
+  src.on('data', ondata);
+  function ondata(chunk) {
+    debug('ondata');
+    var ret = dest.write(chunk);
+    debug('dest.write', ret);
+    if (ret === false) {
+      // If the user unpiped during `dest.write()`, it is possible
+      // to get stuck in a permanently paused state if that write
+      // also returned false.
+      // => Check whether `dest` is still a piping destination.
+      if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
+        debug('false write response, pause', state.awaitDrain);
+        state.awaitDrain++;
+      }
+      src.pause();
+    }
+  }
+
+  // if the dest has an error, then stop piping into it.
+  // however, don't suppress the throwing behavior for this.
+  function onerror(er) {
+    debug('onerror', er);
+    unpipe();
+    dest.removeListener('error', onerror);
+    if (EElistenerCount(dest, 'error') === 0) errorOrDestroy(dest, er);
+  }
+
+  // Make sure our error handler is attached before userland ones.
+  prependListener(dest, 'error', onerror);
+
+  // Both close and finish should trigger unpipe, but only once.
+  function onclose() {
+    dest.removeListener('finish', onfinish);
+    unpipe();
+  }
+  dest.once('close', onclose);
+  function onfinish() {
+    debug('onfinish');
+    dest.removeListener('close', onclose);
+    unpipe();
+  }
+  dest.once('finish', onfinish);
+  function unpipe() {
+    debug('unpipe');
+    src.unpipe(dest);
+  }
+
+  // tell the dest that it's being piped to
+  dest.emit('pipe', src);
+
+  // start the flow if it hasn't been started already.
+  if (!state.flowing) {
+    debug('pipe resume');
+    src.resume();
+  }
+  return dest;
+};
+function pipeOnDrain(src) {
+  return function pipeOnDrainFunctionResult() {
+    var state = src._readableState;
+    debug('pipeOnDrain', state.awaitDrain);
+    if (state.awaitDrain) state.awaitDrain--;
+    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
+      state.flowing = true;
+      flow(src);
+    }
+  };
+}
+Readable.prototype.unpipe = function (dest) {
+  var state = this._readableState;
+  var unpipeInfo = {
+    hasUnpiped: false
+  };
+
+  // if we're not piping anywhere, then do nothing.
+  if (state.pipesCount === 0) return this;
+
+  // just one destination.  most common case.
+  if (state.pipesCount === 1) {
+    // passed in one, but it's not the right one.
+    if (dest && dest !== state.pipes) return this;
+    if (!dest) dest = state.pipes;
+
+    // got a match.
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    if (dest) dest.emit('unpipe', this, unpipeInfo);
+    return this;
+  }
+
+  // slow case. multiple pipe destinations.
+
+  if (!dest) {
+    // remove all.
+    var dests = state.pipes;
+    var len = state.pipesCount;
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    for (var i = 0; i < len; i++) dests[i].emit('unpipe', this, {
+      hasUnpiped: false
+    });
+    return this;
+  }
+
+  // try to find the right one.
+  var index = indexOf(state.pipes, dest);
+  if (index === -1) return this;
+  state.pipes.splice(index, 1);
+  state.pipesCount -= 1;
+  if (state.pipesCount === 1) state.pipes = state.pipes[0];
+  dest.emit('unpipe', this, unpipeInfo);
+  return this;
+};
+
+// set up data events if they are asked for
+// Ensure readable listeners eventually get something
+Readable.prototype.on = function (ev, fn) {
+  var res = Stream.prototype.on.call(this, ev, fn);
+  var state = this._readableState;
+  if (ev === 'data') {
+    // update readableListening so that resume() may be a no-op
+    // a few lines down. This is needed to support once('readable').
+    state.readableListening = this.listenerCount('readable') > 0;
+
+    // Try start flowing on next tick if stream isn't explicitly paused
+    if (state.flowing !== false) this.resume();
+  } else if (ev === 'readable') {
+    if (!state.endEmitted && !state.readableListening) {
+      state.readableListening = state.needReadable = true;
+      state.flowing = false;
+      state.emittedReadable = false;
+      debug('on readable', state.length, state.reading);
+      if (state.length) {
+        emitReadable(this);
+      } else if (!state.reading) {
+        process.nextTick(nReadingNextTick, this);
+      }
+    }
+  }
+  return res;
+};
+Readable.prototype.addListener = Readable.prototype.on;
+Readable.prototype.removeListener = function (ev, fn) {
+  var res = Stream.prototype.removeListener.call(this, ev, fn);
+  if (ev === 'readable') {
+    // We need to check if there is someone still listening to
+    // readable and reset the state. However this needs to happen
+    // after readable has been emitted but before I/O (nextTick) to
+    // support once('readable', fn) cycles. This means that calling
+    // resume within the same tick will have no
+    // effect.
+    process.nextTick(updateReadableListening, this);
+  }
+  return res;
+};
+Readable.prototype.removeAllListeners = function (ev) {
+  var res = Stream.prototype.removeAllListeners.apply(this, arguments);
+  if (ev === 'readable' || ev === undefined) {
+    // We need to check if there is someone still listening to
+    // readable and reset the state. However this needs to happen
+    // after readable has been emitted but before I/O (nextTick) to
+    // support once('readable', fn) cycles. This means that calling
+    // resume within the same tick will have no
+    // effect.
+    process.nextTick(updateReadableListening, this);
+  }
+  return res;
+};
+function updateReadableListening(self) {
+  var state = self._readableState;
+  state.readableListening = self.listenerCount('readable') > 0;
+  if (state.resumeScheduled && !state.paused) {
+    // flowing needs to be set to true now, otherwise
+    // the upcoming resume will not flow.
+    state.flowing = true;
+
+    // crude way to check if we should resume
+  } else if (self.listenerCount('data') > 0) {
+    self.resume();
+  }
+}
+function nReadingNextTick(self) {
+  debug('readable nexttick read 0');
+  self.read(0);
+}
+
+// pause() and resume() are remnants of the legacy readable stream API
+// If the user uses them, then switch into old mode.
+Readable.prototype.resume = function () {
+  var state = this._readableState;
+  if (!state.flowing) {
+    debug('resume');
+    // we flow only if there is no one listening
+    // for readable, but we still have to call
+    // resume()
+    state.flowing = !state.readableListening;
+    resume(this, state);
+  }
+  state.paused = false;
+  return this;
+};
+function resume(stream, state) {
+  if (!state.resumeScheduled) {
+    state.resumeScheduled = true;
+    process.nextTick(resume_, stream, state);
+  }
+}
+function resume_(stream, state) {
+  debug('resume', state.reading);
+  if (!state.reading) {
+    stream.read(0);
+  }
+  state.resumeScheduled = false;
+  stream.emit('resume');
+  flow(stream);
+  if (state.flowing && !state.reading) stream.read(0);
+}
+Readable.prototype.pause = function () {
+  debug('call pause flowing=%j', this._readableState.flowing);
+  if (this._readableState.flowing !== false) {
+    debug('pause');
+    this._readableState.flowing = false;
+    this.emit('pause');
+  }
+  this._readableState.paused = true;
+  return this;
+};
+function flow(stream) {
+  var state = stream._readableState;
+  debug('flow', state.flowing);
+  while (state.flowing && stream.read() !== null);
+}
+
+// wrap an old-style stream as the async data source.
+// This is *not* part of the readable stream interface.
+// It is an ugly unfortunate mess of history.
+Readable.prototype.wrap = function (stream) {
+  var _this = this;
+  var state = this._readableState;
+  var paused = false;
+  stream.on('end', function () {
+    debug('wrapped end');
+    if (state.decoder && !state.ended) {
+      var chunk = state.decoder.end();
+      if (chunk && chunk.length) _this.push(chunk);
+    }
+    _this.push(null);
+  });
+  stream.on('data', function (chunk) {
+    debug('wrapped data');
+    if (state.decoder) chunk = state.decoder.write(chunk);
+
+    // don't skip over falsy values in objectMode
+    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;
+    var ret = _this.push(chunk);
+    if (!ret) {
+      paused = true;
+      stream.pause();
+    }
+  });
+
+  // proxy all the other methods.
+  // important when wrapping filters and duplexes.
+  for (var i in stream) {
+    if (this[i] === undefined && typeof stream[i] === 'function') {
+      this[i] = function methodWrap(method) {
+        return function methodWrapReturnFunction() {
+          return stream[method].apply(stream, arguments);
+        };
+      }(i);
+    }
+  }
+
+  // proxy certain important events.
+  for (var n = 0; n < kProxyEvents.length; n++) {
+    stream.on(kProxyEvents[n], this.emit.bind(this, kProxyEvents[n]));
+  }
+
+  // when we try to consume some more bytes, simply unpause the
+  // underlying stream.
+  this._read = function (n) {
+    debug('wrapped _read', n);
+    if (paused) {
+      paused = false;
+      stream.resume();
+    }
+  };
+  return this;
+};
+if (typeof Symbol === 'function') {
+  Readable.prototype[Symbol.asyncIterator] = function () {
+    if (createReadableStreamAsyncIterator === undefined) {
+      createReadableStreamAsyncIterator = require('./internal/streams/async_iterator');
+    }
+    return createReadableStreamAsyncIterator(this);
+  };
+}
+Object.defineProperty(Readable.prototype, 'readableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.highWaterMark;
+  }
+});
+Object.defineProperty(Readable.prototype, 'readableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState && this._readableState.buffer;
+  }
+});
+Object.defineProperty(Readable.prototype, 'readableFlowing', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.flowing;
+  },
+  set: function set(state) {
+    if (this._readableState) {
+      this._readableState.flowing = state;
+    }
+  }
+});
+
+// exposed for testing purposes only.
+Readable._fromList = fromList;
+Object.defineProperty(Readable.prototype, 'readableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.length;
+  }
+});
+
+// Pluck off n bytes from an array of buffers.
+// Length is the combined lengths of all the buffers in the list.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function fromList(n, state) {
+  // nothing buffered
+  if (state.length === 0) return null;
+  var ret;
+  if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
+    // read it all, truncate the list
+    if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.first();else ret = state.buffer.concat(state.length);
+    state.buffer.clear();
+  } else {
+    // read part of list
+    ret = state.buffer.consume(n, state.decoder);
+  }
+  return ret;
+}
+function endReadable(stream) {
+  var state = stream._readableState;
+  debug('endReadable', state.endEmitted);
+  if (!state.endEmitted) {
+    state.ended = true;
+    process.nextTick(endReadableNT, state, stream);
+  }
+}
+function endReadableNT(state, stream) {
+  debug('endReadableNT', state.endEmitted, state.length);
+
+  // Check that we didn't get one last unshift.
+  if (!state.endEmitted && state.length === 0) {
+    state.endEmitted = true;
+    stream.readable = false;
+    stream.emit('end');
+    if (state.autoDestroy) {
+      // In case of duplex streams we need a way to detect
+      // if the writable side is ready for autoDestroy as well
+      var wState = stream._writableState;
+      if (!wState || wState.autoDestroy && wState.finished) {
+        stream.destroy();
+      }
+    }
+  }
+}
+if (typeof Symbol === 'function') {
+  Readable.from = function (iterable, opts) {
+    if (from === undefined) {
+      from = require('./internal/streams/from');
+    }
+    return from(Readable, iterable, opts);
+  };
+}
+function indexOf(xs, x) {
+  for (var i = 0, l = xs.length; i < l; i++) {
+    if (xs[i] === x) return i;
+  }
+  return -1;
+}
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/_stream_transform.js b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_transform.js
new file mode 100644
index 0000000..1ccb715
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_transform.js
@@ -0,0 +1,190 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a transform stream is a readable/writable stream where you do
+// something with the data.  Sometimes it's called a "filter",
+// but that's not a great name for it, since that implies a thing where
+// some bits pass through, and others are simply ignored.  (That would
+// be a valid example of a transform, of course.)
+//
+// While the output is causally related to the input, it's not a
+// necessarily symmetric or synchronous transformation.  For example,
+// a zlib stream might take multiple plain-text writes(), and then
+// emit a single compressed chunk some time in the future.
+//
+// Here's how this works:
+//
+// The Transform stream has all the aspects of the readable and writable
+// stream classes.  When you write(chunk), that calls _write(chunk,cb)
+// internally, and returns false if there's a lot of pending writes
+// buffered up.  When you call read(), that calls _read(n) until
+// there's enough pending readable data buffered up.
+//
+// In a transform stream, the written data is placed in a buffer.  When
+// _read(n) is called, it transforms the queued up data, calling the
+// buffered _write cb's as it consumes chunks.  If consuming a single
+// written chunk would result in multiple output chunks, then the first
+// outputted bit calls the readcb, and subsequent chunks just go into
+// the read buffer, and will cause it to emit 'readable' if necessary.
+//
+// This way, back-pressure is actually determined by the reading side,
+// since _read has to be called to start processing a new chunk.  However,
+// a pathological inflate type of transform can cause excessive buffering
+// here.  For example, imagine a stream where every byte of input is
+// interpreted as an integer from 0-255, and then results in that many
+// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
+// 1kb of data being output.  In this case, you could write a very small
+// amount of input, and end up with a very large amount of output.  In
+// such a pathological inflating mechanism, there'd be no way to tell
+// the system to stop doing the transform.  A single 4MB write could
+// cause the system to run out of memory.
+//
+// However, even in such a pathological case, only a single written chunk
+// would be consumed, and then the rest would wait (un-transformed) until
+// the results of the previous transformed chunk were consumed.
+
+'use strict';
+
+module.exports = Transform;
+var _require$codes = require('../errors').codes,
+  ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
+  ERR_TRANSFORM_ALREADY_TRANSFORMING = _require$codes.ERR_TRANSFORM_ALREADY_TRANSFORMING,
+  ERR_TRANSFORM_WITH_LENGTH_0 = _require$codes.ERR_TRANSFORM_WITH_LENGTH_0;
+var Duplex = require('./_stream_duplex');
+require('inherits')(Transform, Duplex);
+function afterTransform(er, data) {
+  var ts = this._transformState;
+  ts.transforming = false;
+  var cb = ts.writecb;
+  if (cb === null) {
+    return this.emit('error', new ERR_MULTIPLE_CALLBACK());
+  }
+  ts.writechunk = null;
+  ts.writecb = null;
+  if (data != null)
+    // single equals check for both `null` and `undefined`
+    this.push(data);
+  cb(er);
+  var rs = this._readableState;
+  rs.reading = false;
+  if (rs.needReadable || rs.length < rs.highWaterMark) {
+    this._read(rs.highWaterMark);
+  }
+}
+function Transform(options) {
+  if (!(this instanceof Transform)) return new Transform(options);
+  Duplex.call(this, options);
+  this._transformState = {
+    afterTransform: afterTransform.bind(this),
+    needTransform: false,
+    transforming: false,
+    writecb: null,
+    writechunk: null,
+    writeencoding: null
+  };
+
+  // start out asking for a readable event once data is transformed.
+  this._readableState.needReadable = true;
+
+  // we have implemented the _read method, and done the other things
+  // that Readable wants before the first _read call, so unset the
+  // sync guard flag.
+  this._readableState.sync = false;
+  if (options) {
+    if (typeof options.transform === 'function') this._transform = options.transform;
+    if (typeof options.flush === 'function') this._flush = options.flush;
+  }
+
+  // When the writable side finishes, then flush out anything remaining.
+  this.on('prefinish', prefinish);
+}
+function prefinish() {
+  var _this = this;
+  if (typeof this._flush === 'function' && !this._readableState.destroyed) {
+    this._flush(function (er, data) {
+      done(_this, er, data);
+    });
+  } else {
+    done(this, null, null);
+  }
+}
+Transform.prototype.push = function (chunk, encoding) {
+  this._transformState.needTransform = false;
+  return Duplex.prototype.push.call(this, chunk, encoding);
+};
+
+// This is the part where you do stuff!
+// override this function in implementation classes.
+// 'chunk' is an input chunk.
+//
+// Call `push(newChunk)` to pass along transformed output
+// to the readable side.  You may call 'push' zero or more times.
+//
+// Call `cb(err)` when you are done with this chunk.  If you pass
+// an error, then that'll put the hurt on the whole operation.  If you
+// never call cb(), then you'll never get another chunk.
+Transform.prototype._transform = function (chunk, encoding, cb) {
+  cb(new ERR_METHOD_NOT_IMPLEMENTED('_transform()'));
+};
+Transform.prototype._write = function (chunk, encoding, cb) {
+  var ts = this._transformState;
+  ts.writecb = cb;
+  ts.writechunk = chunk;
+  ts.writeencoding = encoding;
+  if (!ts.transforming) {
+    var rs = this._readableState;
+    if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
+  }
+};
+
+// Doesn't matter what the args are here.
+// _transform does all the work.
+// That we got here means that the readable side wants more data.
+Transform.prototype._read = function (n) {
+  var ts = this._transformState;
+  if (ts.writechunk !== null && !ts.transforming) {
+    ts.transforming = true;
+    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
+  } else {
+    // mark that we need a transform, so that any data that comes in
+    // will get processed, now that we've asked for it.
+    ts.needTransform = true;
+  }
+};
+Transform.prototype._destroy = function (err, cb) {
+  Duplex.prototype._destroy.call(this, err, function (err2) {
+    cb(err2);
+  });
+};
+function done(stream, er, data) {
+  if (er) return stream.emit('error', er);
+  if (data != null)
+    // single equals check for both `null` and `undefined`
+    stream.push(data);
+
+  // TODO(BridgeAR): Write a test for these two error cases
+  // if there's nothing in the write buffer, then that means
+  // that nothing more will ever be provided
+  if (stream._writableState.length) throw new ERR_TRANSFORM_WITH_LENGTH_0();
+  if (stream._transformState.transforming) throw new ERR_TRANSFORM_ALREADY_TRANSFORMING();
+  return stream.push(null);
+}
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/_stream_writable.js b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_writable.js
new file mode 100644
index 0000000..292415e
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/_stream_writable.js
@@ -0,0 +1,641 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// A bit simpler than readable streams.
+// Implement an async ._write(chunk, encoding, cb), and it'll handle all
+// the drain event emission and buffering.
+
+'use strict';
+
+module.exports = Writable;
+
+/* <replacement> */
+function WriteReq(chunk, encoding, cb) {
+  this.chunk = chunk;
+  this.encoding = encoding;
+  this.callback = cb;
+  this.next = null;
+}
+
+// It seems a linked list but it is not
+// there will be only 2 of these for each stream
+function CorkedRequest(state) {
+  var _this = this;
+  this.next = null;
+  this.entry = null;
+  this.finish = function () {
+    onCorkedFinish(_this, state);
+  };
+}
+/* </replacement> */
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Writable.WritableState = WritableState;
+
+/*<replacement>*/
+var internalUtil = {
+  deprecate: require('util-deprecate')
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+var Buffer = require('buffer').Buffer;
+var OurUint8Array = (typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : typeof self !== 'undefined' ? self : {}).Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+var destroyImpl = require('./internal/streams/destroy');
+var _require = require('./internal/streams/state'),
+  getHighWaterMark = _require.getHighWaterMark;
+var _require$codes = require('../errors').codes,
+  ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
+  ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
+  ERR_STREAM_CANNOT_PIPE = _require$codes.ERR_STREAM_CANNOT_PIPE,
+  ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED,
+  ERR_STREAM_NULL_VALUES = _require$codes.ERR_STREAM_NULL_VALUES,
+  ERR_STREAM_WRITE_AFTER_END = _require$codes.ERR_STREAM_WRITE_AFTER_END,
+  ERR_UNKNOWN_ENCODING = _require$codes.ERR_UNKNOWN_ENCODING;
+var errorOrDestroy = destroyImpl.errorOrDestroy;
+require('inherits')(Writable, Stream);
+function nop() {}
+function WritableState(options, stream, isDuplex) {
+  Duplex = Duplex || require('./_stream_duplex');
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream,
+  // e.g. options.readableObjectMode vs. options.writableObjectMode, etc.
+  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex;
+
+  // object stream flag to indicate whether or not this stream
+  // contains buffers or objects.
+  this.objectMode = !!options.objectMode;
+  if (isDuplex) this.objectMode = this.objectMode || !!options.writableObjectMode;
+
+  // the point at which write() starts returning false
+  // Note: 0 is a valid value, means that we always return false if
+  // the entire buffer is not flushed immediately on write()
+  this.highWaterMark = getHighWaterMark(this, options, 'writableHighWaterMark', isDuplex);
+
+  // if _final has been called
+  this.finalCalled = false;
+
+  // drain event flag.
+  this.needDrain = false;
+  // at the start of calling end()
+  this.ending = false;
+  // when end() has been called, and returned
+  this.ended = false;
+  // when 'finish' is emitted
+  this.finished = false;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // should we decode strings into buffers before passing to _write?
+  // this is here so that some node-core streams can optimize string
+  // handling at a lower level.
+  var noDecode = options.decodeStrings === false;
+  this.decodeStrings = !noDecode;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // not an actual buffer we keep track of, but a measurement
+  // of how much we're waiting to get pushed to some underlying
+  // socket or file.
+  this.length = 0;
+
+  // a flag to see when we're in the middle of a write.
+  this.writing = false;
+
+  // when true all writes will be buffered until .uncork() call
+  this.corked = 0;
+
+  // a flag to be able to tell if the onwrite cb is called immediately,
+  // or on a later tick.  We set this to true at first, because any
+  // actions that shouldn't happen until "later" should generally also
+  // not happen before the first write call.
+  this.sync = true;
+
+  // a flag to know if we're processing previously buffered items, which
+  // may call the _write() callback in the same tick, so that we don't
+  // end up in an overlapped onwrite situation.
+  this.bufferProcessing = false;
+
+  // the callback that's passed to _write(chunk,cb)
+  this.onwrite = function (er) {
+    onwrite(stream, er);
+  };
+
+  // the callback that the user supplies to write(chunk,encoding,cb)
+  this.writecb = null;
+
+  // the amount that is being written when _write is called.
+  this.writelen = 0;
+  this.bufferedRequest = null;
+  this.lastBufferedRequest = null;
+
+  // number of pending user-supplied write callbacks
+  // this must be 0 before 'finish' can be emitted
+  this.pendingcb = 0;
+
+  // emit prefinish if the only thing we're waiting for is _write cbs
+  // This is relevant for synchronous Transform streams
+  this.prefinished = false;
+
+  // True if the error was already emitted and should not be thrown again
+  this.errorEmitted = false;
+
+  // Should close be emitted on destroy. Defaults to true.
+  this.emitClose = options.emitClose !== false;
+
+  // Should .destroy() be called after 'finish' (and potentially 'end')
+  this.autoDestroy = !!options.autoDestroy;
+
+  // count buffered requests
+  this.bufferedRequestCount = 0;
+
+  // allocate the first CorkedRequest, there is always
+  // one allocated and free to use, and we maintain at most two
+  this.corkedRequestsFree = new CorkedRequest(this);
+}
+WritableState.prototype.getBuffer = function getBuffer() {
+  var current = this.bufferedRequest;
+  var out = [];
+  while (current) {
+    out.push(current);
+    current = current.next;
+  }
+  return out;
+};
+(function () {
+  try {
+    Object.defineProperty(WritableState.prototype, 'buffer', {
+      get: internalUtil.deprecate(function writableStateBufferGetter() {
+        return this.getBuffer();
+      }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.', 'DEP0003')
+    });
+  } catch (_) {}
+})();
+
+// Test _writableState for inheritance to account for Duplex streams,
+// whose prototype chain only points to Readable.
+var realHasInstance;
+if (typeof Symbol === 'function' && Symbol.hasInstance && typeof Function.prototype[Symbol.hasInstance] === 'function') {
+  realHasInstance = Function.prototype[Symbol.hasInstance];
+  Object.defineProperty(Writable, Symbol.hasInstance, {
+    value: function value(object) {
+      if (realHasInstance.call(this, object)) return true;
+      if (this !== Writable) return false;
+      return object && object._writableState instanceof WritableState;
+    }
+  });
+} else {
+  realHasInstance = function realHasInstance(object) {
+    return object instanceof this;
+  };
+}
+function Writable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  // Writable ctor is applied to Duplexes, too.
+  // `realHasInstance` is necessary because using plain `instanceof`
+  // would return false, as no `_writableState` property is attached.
+
+  // Trying to use the custom `instanceof` for Writable here will also break the
+  // Node.js LazyTransform implementation, which has a non-trivial getter for
+  // `_writableState` that would lead to infinite recursion.
+
+  // Checking for a Stream.Duplex instance is faster here instead of inside
+  // the WritableState constructor, at least with V8 6.5
+  var isDuplex = this instanceof Duplex;
+  if (!isDuplex && !realHasInstance.call(Writable, this)) return new Writable(options);
+  this._writableState = new WritableState(options, this, isDuplex);
+
+  // legacy.
+  this.writable = true;
+  if (options) {
+    if (typeof options.write === 'function') this._write = options.write;
+    if (typeof options.writev === 'function') this._writev = options.writev;
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+    if (typeof options.final === 'function') this._final = options.final;
+  }
+  Stream.call(this);
+}
+
+// Otherwise people can pipe Writable streams, which is just wrong.
+Writable.prototype.pipe = function () {
+  errorOrDestroy(this, new ERR_STREAM_CANNOT_PIPE());
+};
+function writeAfterEnd(stream, cb) {
+  var er = new ERR_STREAM_WRITE_AFTER_END();
+  // TODO: defer error events consistently everywhere, not just the cb
+  errorOrDestroy(stream, er);
+  process.nextTick(cb, er);
+}
+
+// Checks that a user-supplied chunk is valid, especially for the particular
+// mode the stream is in. Currently this means that `null` is never accepted
+// and undefined/non-string values are only allowed in object mode.
+function validChunk(stream, state, chunk, cb) {
+  var er;
+  if (chunk === null) {
+    er = new ERR_STREAM_NULL_VALUES();
+  } else if (typeof chunk !== 'string' && !state.objectMode) {
+    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
+  }
+  if (er) {
+    errorOrDestroy(stream, er);
+    process.nextTick(cb, er);
+    return false;
+  }
+  return true;
+}
+Writable.prototype.write = function (chunk, encoding, cb) {
+  var state = this._writableState;
+  var ret = false;
+  var isBuf = !state.objectMode && _isUint8Array(chunk);
+  if (isBuf && !Buffer.isBuffer(chunk)) {
+    chunk = _uint8ArrayToBuffer(chunk);
+  }
+  if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+  if (isBuf) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;
+  if (typeof cb !== 'function') cb = nop;
+  if (state.ending) writeAfterEnd(this, cb);else if (isBuf || validChunk(this, state, chunk, cb)) {
+    state.pendingcb++;
+    ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
+  }
+  return ret;
+};
+Writable.prototype.cork = function () {
+  this._writableState.corked++;
+};
+Writable.prototype.uncork = function () {
+  var state = this._writableState;
+  if (state.corked) {
+    state.corked--;
+    if (!state.writing && !state.corked && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
+  }
+};
+Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
+  // node::ParseEncoding() requires lower case.
+  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
+  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new ERR_UNKNOWN_ENCODING(encoding);
+  this._writableState.defaultEncoding = encoding;
+  return this;
+};
+Object.defineProperty(Writable.prototype, 'writableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState && this._writableState.getBuffer();
+  }
+});
+function decodeChunk(state, chunk, encoding) {
+  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
+    chunk = Buffer.from(chunk, encoding);
+  }
+  return chunk;
+}
+Object.defineProperty(Writable.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.highWaterMark;
+  }
+});
+
+// if we're already writing something, then just put this
+// in the queue, and wait our turn.  Otherwise, call _write
+// If we return false, then we need a drain event, so set that flag.
+function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
+  if (!isBuf) {
+    var newChunk = decodeChunk(state, chunk, encoding);
+    if (chunk !== newChunk) {
+      isBuf = true;
+      encoding = 'buffer';
+      chunk = newChunk;
+    }
+  }
+  var len = state.objectMode ? 1 : chunk.length;
+  state.length += len;
+  var ret = state.length < state.highWaterMark;
+  // we must ensure that previous needDrain will not be reset to false.
+  if (!ret) state.needDrain = true;
+  if (state.writing || state.corked) {
+    var last = state.lastBufferedRequest;
+    state.lastBufferedRequest = {
+      chunk: chunk,
+      encoding: encoding,
+      isBuf: isBuf,
+      callback: cb,
+      next: null
+    };
+    if (last) {
+      last.next = state.lastBufferedRequest;
+    } else {
+      state.bufferedRequest = state.lastBufferedRequest;
+    }
+    state.bufferedRequestCount += 1;
+  } else {
+    doWrite(stream, state, false, len, chunk, encoding, cb);
+  }
+  return ret;
+}
+function doWrite(stream, state, writev, len, chunk, encoding, cb) {
+  state.writelen = len;
+  state.writecb = cb;
+  state.writing = true;
+  state.sync = true;
+  if (state.destroyed) state.onwrite(new ERR_STREAM_DESTROYED('write'));else if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
+  state.sync = false;
+}
+function onwriteError(stream, state, sync, er, cb) {
+  --state.pendingcb;
+  if (sync) {
+    // defer the callback if we are being called synchronously
+    // to avoid piling up things on the stack
+    process.nextTick(cb, er);
+    // this can emit finish, and it will always happen
+    // after error
+    process.nextTick(finishMaybe, stream, state);
+    stream._writableState.errorEmitted = true;
+    errorOrDestroy(stream, er);
+  } else {
+    // the caller expect this to happen before if
+    // it is async
+    cb(er);
+    stream._writableState.errorEmitted = true;
+    errorOrDestroy(stream, er);
+    // this can emit finish, but finish must
+    // always follow error
+    finishMaybe(stream, state);
+  }
+}
+function onwriteStateUpdate(state) {
+  state.writing = false;
+  state.writecb = null;
+  state.length -= state.writelen;
+  state.writelen = 0;
+}
+function onwrite(stream, er) {
+  var state = stream._writableState;
+  var sync = state.sync;
+  var cb = state.writecb;
+  if (typeof cb !== 'function') throw new ERR_MULTIPLE_CALLBACK();
+  onwriteStateUpdate(state);
+  if (er) onwriteError(stream, state, sync, er, cb);else {
+    // Check if we're actually ready to finish, but don't emit yet
+    var finished = needFinish(state) || stream.destroyed;
+    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
+      clearBuffer(stream, state);
+    }
+    if (sync) {
+      process.nextTick(afterWrite, stream, state, finished, cb);
+    } else {
+      afterWrite(stream, state, finished, cb);
+    }
+  }
+}
+function afterWrite(stream, state, finished, cb) {
+  if (!finished) onwriteDrain(stream, state);
+  state.pendingcb--;
+  cb();
+  finishMaybe(stream, state);
+}
+
+// Must force callback to be called on nextTick, so that we don't
+// emit 'drain' before the write() consumer gets the 'false' return
+// value, and has a chance to attach a 'drain' listener.
+function onwriteDrain(stream, state) {
+  if (state.length === 0 && state.needDrain) {
+    state.needDrain = false;
+    stream.emit('drain');
+  }
+}
+
+// if there's something in the buffer waiting, then process it
+function clearBuffer(stream, state) {
+  state.bufferProcessing = true;
+  var entry = state.bufferedRequest;
+  if (stream._writev && entry && entry.next) {
+    // Fast case, write everything using _writev()
+    var l = state.bufferedRequestCount;
+    var buffer = new Array(l);
+    var holder = state.corkedRequestsFree;
+    holder.entry = entry;
+    var count = 0;
+    var allBuffers = true;
+    while (entry) {
+      buffer[count] = entry;
+      if (!entry.isBuf) allBuffers = false;
+      entry = entry.next;
+      count += 1;
+    }
+    buffer.allBuffers = allBuffers;
+    doWrite(stream, state, true, state.length, buffer, '', holder.finish);
+
+    // doWrite is almost always async, defer these to save a bit of time
+    // as the hot path ends with doWrite
+    state.pendingcb++;
+    state.lastBufferedRequest = null;
+    if (holder.next) {
+      state.corkedRequestsFree = holder.next;
+      holder.next = null;
+    } else {
+      state.corkedRequestsFree = new CorkedRequest(state);
+    }
+    state.bufferedRequestCount = 0;
+  } else {
+    // Slow case, write chunks one-by-one
+    while (entry) {
+      var chunk = entry.chunk;
+      var encoding = entry.encoding;
+      var cb = entry.callback;
+      var len = state.objectMode ? 1 : chunk.length;
+      doWrite(stream, state, false, len, chunk, encoding, cb);
+      entry = entry.next;
+      state.bufferedRequestCount--;
+      // if we didn't call the onwrite immediately, then
+      // it means that we need to wait until it does.
+      // also, that means that the chunk and cb are currently
+      // being processed, so move the buffer counter past them.
+      if (state.writing) {
+        break;
+      }
+    }
+    if (entry === null) state.lastBufferedRequest = null;
+  }
+  state.bufferedRequest = entry;
+  state.bufferProcessing = false;
+}
+Writable.prototype._write = function (chunk, encoding, cb) {
+  cb(new ERR_METHOD_NOT_IMPLEMENTED('_write()'));
+};
+Writable.prototype._writev = null;
+Writable.prototype.end = function (chunk, encoding, cb) {
+  var state = this._writableState;
+  if (typeof chunk === 'function') {
+    cb = chunk;
+    chunk = null;
+    encoding = null;
+  } else if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding);
+
+  // .end() fully uncorks
+  if (state.corked) {
+    state.corked = 1;
+    this.uncork();
+  }
+
+  // ignore unnecessary end() calls.
+  if (!state.ending) endWritable(this, state, cb);
+  return this;
+};
+Object.defineProperty(Writable.prototype, 'writableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.length;
+  }
+});
+function needFinish(state) {
+  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
+}
+function callFinal(stream, state) {
+  stream._final(function (err) {
+    state.pendingcb--;
+    if (err) {
+      errorOrDestroy(stream, err);
+    }
+    state.prefinished = true;
+    stream.emit('prefinish');
+    finishMaybe(stream, state);
+  });
+}
+function prefinish(stream, state) {
+  if (!state.prefinished && !state.finalCalled) {
+    if (typeof stream._final === 'function' && !state.destroyed) {
+      state.pendingcb++;
+      state.finalCalled = true;
+      process.nextTick(callFinal, stream, state);
+    } else {
+      state.prefinished = true;
+      stream.emit('prefinish');
+    }
+  }
+}
+function finishMaybe(stream, state) {
+  var need = needFinish(state);
+  if (need) {
+    prefinish(stream, state);
+    if (state.pendingcb === 0) {
+      state.finished = true;
+      stream.emit('finish');
+      if (state.autoDestroy) {
+        // In case of duplex streams we need a way to detect
+        // if the readable side is ready for autoDestroy as well
+        var rState = stream._readableState;
+        if (!rState || rState.autoDestroy && rState.endEmitted) {
+          stream.destroy();
+        }
+      }
+    }
+  }
+  return need;
+}
+function endWritable(stream, state, cb) {
+  state.ending = true;
+  finishMaybe(stream, state);
+  if (cb) {
+    if (state.finished) process.nextTick(cb);else stream.once('finish', cb);
+  }
+  state.ended = true;
+  stream.writable = false;
+}
+function onCorkedFinish(corkReq, state, err) {
+  var entry = corkReq.entry;
+  corkReq.entry = null;
+  while (entry) {
+    var cb = entry.callback;
+    state.pendingcb--;
+    cb(err);
+    entry = entry.next;
+  }
+
+  // reuse the free corkReq.
+  state.corkedRequestsFree.next = corkReq;
+}
+Object.defineProperty(Writable.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._writableState === undefined) {
+      return false;
+    }
+    return this._writableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._writableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._writableState.destroyed = value;
+  }
+});
+Writable.prototype.destroy = destroyImpl.destroy;
+Writable.prototype._undestroy = destroyImpl.undestroy;
+Writable.prototype._destroy = function (err, cb) {
+  cb(err);
+};
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/async_iterator.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/async_iterator.js
new file mode 100644
index 0000000..742c5a4
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/async_iterator.js
@@ -0,0 +1,180 @@
+'use strict';
+
+var _Object$setPrototypeO;
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+var finished = require('./end-of-stream');
+var kLastResolve = Symbol('lastResolve');
+var kLastReject = Symbol('lastReject');
+var kError = Symbol('error');
+var kEnded = Symbol('ended');
+var kLastPromise = Symbol('lastPromise');
+var kHandlePromise = Symbol('handlePromise');
+var kStream = Symbol('stream');
+function createIterResult(value, done) {
+  return {
+    value: value,
+    done: done
+  };
+}
+function readAndResolve(iter) {
+  var resolve = iter[kLastResolve];
+  if (resolve !== null) {
+    var data = iter[kStream].read();
+    // we defer if data is null
+    // we can be expecting either 'end' or
+    // 'error'
+    if (data !== null) {
+      iter[kLastPromise] = null;
+      iter[kLastResolve] = null;
+      iter[kLastReject] = null;
+      resolve(createIterResult(data, false));
+    }
+  }
+}
+function onReadable(iter) {
+  // we wait for the next tick, because it might
+  // emit an error with process.nextTick
+  process.nextTick(readAndResolve, iter);
+}
+function wrapForNext(lastPromise, iter) {
+  return function (resolve, reject) {
+    lastPromise.then(function () {
+      if (iter[kEnded]) {
+        resolve(createIterResult(undefined, true));
+        return;
+      }
+      iter[kHandlePromise](resolve, reject);
+    }, reject);
+  };
+}
+var AsyncIteratorPrototype = Object.getPrototypeOf(function () {});
+var ReadableStreamAsyncIteratorPrototype = Object.setPrototypeOf((_Object$setPrototypeO = {
+  get stream() {
+    return this[kStream];
+  },
+  next: function next() {
+    var _this = this;
+    // if we have detected an error in the meanwhile
+    // reject straight away
+    var error = this[kError];
+    if (error !== null) {
+      return Promise.reject(error);
+    }
+    if (this[kEnded]) {
+      return Promise.resolve(createIterResult(undefined, true));
+    }
+    if (this[kStream].destroyed) {
+      // We need to defer via nextTick because if .destroy(err) is
+      // called, the error will be emitted via nextTick, and
+      // we cannot guarantee that there is no error lingering around
+      // waiting to be emitted.
+      return new Promise(function (resolve, reject) {
+        process.nextTick(function () {
+          if (_this[kError]) {
+            reject(_this[kError]);
+          } else {
+            resolve(createIterResult(undefined, true));
+          }
+        });
+      });
+    }
+
+    // if we have multiple next() calls
+    // we will wait for the previous Promise to finish
+    // this logic is optimized to support for await loops,
+    // where next() is only called once at a time
+    var lastPromise = this[kLastPromise];
+    var promise;
+    if (lastPromise) {
+      promise = new Promise(wrapForNext(lastPromise, this));
+    } else {
+      // fast path needed to support multiple this.push()
+      // without triggering the next() queue
+      var data = this[kStream].read();
+      if (data !== null) {
+        return Promise.resolve(createIterResult(data, false));
+      }
+      promise = new Promise(this[kHandlePromise]);
+    }
+    this[kLastPromise] = promise;
+    return promise;
+  }
+}, _defineProperty(_Object$setPrototypeO, Symbol.asyncIterator, function () {
+  return this;
+}), _defineProperty(_Object$setPrototypeO, "return", function _return() {
+  var _this2 = this;
+  // destroy(err, cb) is a private API
+  // we can guarantee we have that here, because we control the
+  // Readable class this is attached to
+  return new Promise(function (resolve, reject) {
+    _this2[kStream].destroy(null, function (err) {
+      if (err) {
+        reject(err);
+        return;
+      }
+      resolve(createIterResult(undefined, true));
+    });
+  });
+}), _Object$setPrototypeO), AsyncIteratorPrototype);
+var createReadableStreamAsyncIterator = function createReadableStreamAsyncIterator(stream) {
+  var _Object$create;
+  var iterator = Object.create(ReadableStreamAsyncIteratorPrototype, (_Object$create = {}, _defineProperty(_Object$create, kStream, {
+    value: stream,
+    writable: true
+  }), _defineProperty(_Object$create, kLastResolve, {
+    value: null,
+    writable: true
+  }), _defineProperty(_Object$create, kLastReject, {
+    value: null,
+    writable: true
+  }), _defineProperty(_Object$create, kError, {
+    value: null,
+    writable: true
+  }), _defineProperty(_Object$create, kEnded, {
+    value: stream._readableState.endEmitted,
+    writable: true
+  }), _defineProperty(_Object$create, kHandlePromise, {
+    value: function value(resolve, reject) {
+      var data = iterator[kStream].read();
+      if (data) {
+        iterator[kLastPromise] = null;
+        iterator[kLastResolve] = null;
+        iterator[kLastReject] = null;
+        resolve(createIterResult(data, false));
+      } else {
+        iterator[kLastResolve] = resolve;
+        iterator[kLastReject] = reject;
+      }
+    },
+    writable: true
+  }), _Object$create));
+  iterator[kLastPromise] = null;
+  finished(stream, function (err) {
+    if (err && err.code !== 'ERR_STREAM_PREMATURE_CLOSE') {
+      var reject = iterator[kLastReject];
+      // reject if we are waiting for data in the Promise
+      // returned by next() and store the error
+      if (reject !== null) {
+        iterator[kLastPromise] = null;
+        iterator[kLastResolve] = null;
+        iterator[kLastReject] = null;
+        reject(err);
+      }
+      iterator[kError] = err;
+      return;
+    }
+    var resolve = iterator[kLastResolve];
+    if (resolve !== null) {
+      iterator[kLastPromise] = null;
+      iterator[kLastResolve] = null;
+      iterator[kLastReject] = null;
+      resolve(createIterResult(undefined, true));
+    }
+    iterator[kEnded] = true;
+  });
+  stream.on('readable', onReadable.bind(null, iterator));
+  return iterator;
+};
+module.exports = createReadableStreamAsyncIterator;
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/buffer_list.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/buffer_list.js
new file mode 100644
index 0000000..69bda49
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/buffer_list.js
@@ -0,0 +1,183 @@
+'use strict';
+
+function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); enumerableOnly && (symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; })), keys.push.apply(keys, symbols); } return keys; }
+function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = null != arguments[i] ? arguments[i] : {}; i % 2 ? ownKeys(Object(source), !0).forEach(function (key) { _defineProperty(target, key, source[key]); }) : Object.getOwnPropertyDescriptors ? Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)) : ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } return target; }
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, _toPropertyKey(descriptor.key), descriptor); } }
+function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+var _require = require('buffer'),
+  Buffer = _require.Buffer;
+var _require2 = require('util'),
+  inspect = _require2.inspect;
+var custom = inspect && inspect.custom || 'inspect';
+function copyBuffer(src, target, offset) {
+  Buffer.prototype.copy.call(src, target, offset);
+}
+module.exports = /*#__PURE__*/function () {
+  function BufferList() {
+    _classCallCheck(this, BufferList);
+    this.head = null;
+    this.tail = null;
+    this.length = 0;
+  }
+  _createClass(BufferList, [{
+    key: "push",
+    value: function push(v) {
+      var entry = {
+        data: v,
+        next: null
+      };
+      if (this.length > 0) this.tail.next = entry;else this.head = entry;
+      this.tail = entry;
+      ++this.length;
+    }
+  }, {
+    key: "unshift",
+    value: function unshift(v) {
+      var entry = {
+        data: v,
+        next: this.head
+      };
+      if (this.length === 0) this.tail = entry;
+      this.head = entry;
+      ++this.length;
+    }
+  }, {
+    key: "shift",
+    value: function shift() {
+      if (this.length === 0) return;
+      var ret = this.head.data;
+      if (this.length === 1) this.head = this.tail = null;else this.head = this.head.next;
+      --this.length;
+      return ret;
+    }
+  }, {
+    key: "clear",
+    value: function clear() {
+      this.head = this.tail = null;
+      this.length = 0;
+    }
+  }, {
+    key: "join",
+    value: function join(s) {
+      if (this.length === 0) return '';
+      var p = this.head;
+      var ret = '' + p.data;
+      while (p = p.next) ret += s + p.data;
+      return ret;
+    }
+  }, {
+    key: "concat",
+    value: function concat(n) {
+      if (this.length === 0) return Buffer.alloc(0);
+      var ret = Buffer.allocUnsafe(n >>> 0);
+      var p = this.head;
+      var i = 0;
+      while (p) {
+        copyBuffer(p.data, ret, i);
+        i += p.data.length;
+        p = p.next;
+      }
+      return ret;
+    }
+
+    // Consumes a specified amount of bytes or characters from the buffered data.
+  }, {
+    key: "consume",
+    value: function consume(n, hasStrings) {
+      var ret;
+      if (n < this.head.data.length) {
+        // `slice` is the same for buffers and strings.
+        ret = this.head.data.slice(0, n);
+        this.head.data = this.head.data.slice(n);
+      } else if (n === this.head.data.length) {
+        // First chunk is a perfect match.
+        ret = this.shift();
+      } else {
+        // Result spans more than one buffer.
+        ret = hasStrings ? this._getString(n) : this._getBuffer(n);
+      }
+      return ret;
+    }
+  }, {
+    key: "first",
+    value: function first() {
+      return this.head.data;
+    }
+
+    // Consumes a specified amount of characters from the buffered data.
+  }, {
+    key: "_getString",
+    value: function _getString(n) {
+      var p = this.head;
+      var c = 1;
+      var ret = p.data;
+      n -= ret.length;
+      while (p = p.next) {
+        var str = p.data;
+        var nb = n > str.length ? str.length : n;
+        if (nb === str.length) ret += str;else ret += str.slice(0, n);
+        n -= nb;
+        if (n === 0) {
+          if (nb === str.length) {
+            ++c;
+            if (p.next) this.head = p.next;else this.head = this.tail = null;
+          } else {
+            this.head = p;
+            p.data = str.slice(nb);
+          }
+          break;
+        }
+        ++c;
+      }
+      this.length -= c;
+      return ret;
+    }
+
+    // Consumes a specified amount of bytes from the buffered data.
+  }, {
+    key: "_getBuffer",
+    value: function _getBuffer(n) {
+      var ret = Buffer.allocUnsafe(n);
+      var p = this.head;
+      var c = 1;
+      p.data.copy(ret);
+      n -= p.data.length;
+      while (p = p.next) {
+        var buf = p.data;
+        var nb = n > buf.length ? buf.length : n;
+        buf.copy(ret, ret.length - n, 0, nb);
+        n -= nb;
+        if (n === 0) {
+          if (nb === buf.length) {
+            ++c;
+            if (p.next) this.head = p.next;else this.head = this.tail = null;
+          } else {
+            this.head = p;
+            p.data = buf.slice(nb);
+          }
+          break;
+        }
+        ++c;
+      }
+      this.length -= c;
+      return ret;
+    }
+
+    // Make sure the linked list only shows the minimal necessary information.
+  }, {
+    key: custom,
+    value: function value(_, options) {
+      return inspect(this, _objectSpread(_objectSpread({}, options), {}, {
+        // Only inspect one level.
+        depth: 0,
+        // It should not recurse.
+        customInspect: false
+      }));
+    }
+  }]);
+  return BufferList;
+}();
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/destroy.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/destroy.js
new file mode 100644
index 0000000..31a17c4
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/destroy.js
@@ -0,0 +1,96 @@
+'use strict';
+
+// undocumented cb() API, needed for core, not for public API
+function destroy(err, cb) {
+  var _this = this;
+  var readableDestroyed = this._readableState && this._readableState.destroyed;
+  var writableDestroyed = this._writableState && this._writableState.destroyed;
+  if (readableDestroyed || writableDestroyed) {
+    if (cb) {
+      cb(err);
+    } else if (err) {
+      if (!this._writableState) {
+        process.nextTick(emitErrorNT, this, err);
+      } else if (!this._writableState.errorEmitted) {
+        this._writableState.errorEmitted = true;
+        process.nextTick(emitErrorNT, this, err);
+      }
+    }
+    return this;
+  }
+
+  // we set destroyed to true before firing error callbacks in order
+  // to make it re-entrance safe in case destroy() is called within callbacks
+
+  if (this._readableState) {
+    this._readableState.destroyed = true;
+  }
+
+  // if this is a duplex stream mark the writable part as destroyed as well
+  if (this._writableState) {
+    this._writableState.destroyed = true;
+  }
+  this._destroy(err || null, function (err) {
+    if (!cb && err) {
+      if (!_this._writableState) {
+        process.nextTick(emitErrorAndCloseNT, _this, err);
+      } else if (!_this._writableState.errorEmitted) {
+        _this._writableState.errorEmitted = true;
+        process.nextTick(emitErrorAndCloseNT, _this, err);
+      } else {
+        process.nextTick(emitCloseNT, _this);
+      }
+    } else if (cb) {
+      process.nextTick(emitCloseNT, _this);
+      cb(err);
+    } else {
+      process.nextTick(emitCloseNT, _this);
+    }
+  });
+  return this;
+}
+function emitErrorAndCloseNT(self, err) {
+  emitErrorNT(self, err);
+  emitCloseNT(self);
+}
+function emitCloseNT(self) {
+  if (self._writableState && !self._writableState.emitClose) return;
+  if (self._readableState && !self._readableState.emitClose) return;
+  self.emit('close');
+}
+function undestroy() {
+  if (this._readableState) {
+    this._readableState.destroyed = false;
+    this._readableState.reading = false;
+    this._readableState.ended = false;
+    this._readableState.endEmitted = false;
+  }
+  if (this._writableState) {
+    this._writableState.destroyed = false;
+    this._writableState.ended = false;
+    this._writableState.ending = false;
+    this._writableState.finalCalled = false;
+    this._writableState.prefinished = false;
+    this._writableState.finished = false;
+    this._writableState.errorEmitted = false;
+  }
+}
+function emitErrorNT(self, err) {
+  self.emit('error', err);
+}
+function errorOrDestroy(stream, err) {
+  // We have tests that rely on errors being emitted
+  // in the same tick, so changing this is semver major.
+  // For now when you opt-in to autoDestroy we allow
+  // the error to be emitted nextTick. In a future
+  // semver major update we should change the default to this.
+
+  var rState = stream._readableState;
+  var wState = stream._writableState;
+  if (rState && rState.autoDestroy || wState && wState.autoDestroy) stream.destroy(err);else stream.emit('error', err);
+}
+module.exports = {
+  destroy: destroy,
+  undestroy: undestroy,
+  errorOrDestroy: errorOrDestroy
+};
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/end-of-stream.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/end-of-stream.js
new file mode 100644
index 0000000..59c671b
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/end-of-stream.js
@@ -0,0 +1,86 @@
+// Ported from https://github.com/mafintosh/end-of-stream with
+// permission from the author, Mathias Buus (@mafintosh).
+
+'use strict';
+
+var ERR_STREAM_PREMATURE_CLOSE = require('../../../errors').codes.ERR_STREAM_PREMATURE_CLOSE;
+function once(callback) {
+  var called = false;
+  return function () {
+    if (called) return;
+    called = true;
+    for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
+      args[_key] = arguments[_key];
+    }
+    callback.apply(this, args);
+  };
+}
+function noop() {}
+function isRequest(stream) {
+  return stream.setHeader && typeof stream.abort === 'function';
+}
+function eos(stream, opts, callback) {
+  if (typeof opts === 'function') return eos(stream, null, opts);
+  if (!opts) opts = {};
+  callback = once(callback || noop);
+  var readable = opts.readable || opts.readable !== false && stream.readable;
+  var writable = opts.writable || opts.writable !== false && stream.writable;
+  var onlegacyfinish = function onlegacyfinish() {
+    if (!stream.writable) onfinish();
+  };
+  var writableEnded = stream._writableState && stream._writableState.finished;
+  var onfinish = function onfinish() {
+    writable = false;
+    writableEnded = true;
+    if (!readable) callback.call(stream);
+  };
+  var readableEnded = stream._readableState && stream._readableState.endEmitted;
+  var onend = function onend() {
+    readable = false;
+    readableEnded = true;
+    if (!writable) callback.call(stream);
+  };
+  var onerror = function onerror(err) {
+    callback.call(stream, err);
+  };
+  var onclose = function onclose() {
+    var err;
+    if (readable && !readableEnded) {
+      if (!stream._readableState || !stream._readableState.ended) err = new ERR_STREAM_PREMATURE_CLOSE();
+      return callback.call(stream, err);
+    }
+    if (writable && !writableEnded) {
+      if (!stream._writableState || !stream._writableState.ended) err = new ERR_STREAM_PREMATURE_CLOSE();
+      return callback.call(stream, err);
+    }
+  };
+  var onrequest = function onrequest() {
+    stream.req.on('finish', onfinish);
+  };
+  if (isRequest(stream)) {
+    stream.on('complete', onfinish);
+    stream.on('abort', onclose);
+    if (stream.req) onrequest();else stream.on('request', onrequest);
+  } else if (writable && !stream._writableState) {
+    // legacy streams
+    stream.on('end', onlegacyfinish);
+    stream.on('close', onlegacyfinish);
+  }
+  stream.on('end', onend);
+  stream.on('finish', onfinish);
+  if (opts.error !== false) stream.on('error', onerror);
+  stream.on('close', onclose);
+  return function () {
+    stream.removeListener('complete', onfinish);
+    stream.removeListener('abort', onclose);
+    stream.removeListener('request', onrequest);
+    if (stream.req) stream.req.removeListener('finish', onfinish);
+    stream.removeListener('end', onlegacyfinish);
+    stream.removeListener('close', onlegacyfinish);
+    stream.removeListener('finish', onfinish);
+    stream.removeListener('end', onend);
+    stream.removeListener('error', onerror);
+    stream.removeListener('close', onclose);
+  };
+}
+module.exports = eos;
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/from-browser.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/from-browser.js
new file mode 100644
index 0000000..a4ce56f
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/from-browser.js
@@ -0,0 +1,3 @@
+module.exports = function () {
+  throw new Error('Readable.from is not available in the browser')
+};
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/from.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/from.js
new file mode 100644
index 0000000..0a34ee9
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/from.js
@@ -0,0 +1,52 @@
+'use strict';
+
+function asyncGeneratorStep(gen, resolve, reject, _next, _throw, key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { Promise.resolve(value).then(_next, _throw); } }
+function _asyncToGenerator(fn) { return function () { var self = this, args = arguments; return new Promise(function (resolve, reject) { var gen = fn.apply(self, args); function _next(value) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "next", value); } function _throw(err) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "throw", err); } _next(undefined); }); }; }
+function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); enumerableOnly && (symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; })), keys.push.apply(keys, symbols); } return keys; }
+function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = null != arguments[i] ? arguments[i] : {}; i % 2 ? ownKeys(Object(source), !0).forEach(function (key) { _defineProperty(target, key, source[key]); }) : Object.getOwnPropertyDescriptors ? Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)) : ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } return target; }
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+var ERR_INVALID_ARG_TYPE = require('../../../errors').codes.ERR_INVALID_ARG_TYPE;
+function from(Readable, iterable, opts) {
+  var iterator;
+  if (iterable && typeof iterable.next === 'function') {
+    iterator = iterable;
+  } else if (iterable && iterable[Symbol.asyncIterator]) iterator = iterable[Symbol.asyncIterator]();else if (iterable && iterable[Symbol.iterator]) iterator = iterable[Symbol.iterator]();else throw new ERR_INVALID_ARG_TYPE('iterable', ['Iterable'], iterable);
+  var readable = new Readable(_objectSpread({
+    objectMode: true
+  }, opts));
+  // Reading boolean to protect against _read
+  // being called before last iteration completion.
+  var reading = false;
+  readable._read = function () {
+    if (!reading) {
+      reading = true;
+      next();
+    }
+  };
+  function next() {
+    return _next2.apply(this, arguments);
+  }
+  function _next2() {
+    _next2 = _asyncToGenerator(function* () {
+      try {
+        var _yield$iterator$next = yield iterator.next(),
+          value = _yield$iterator$next.value,
+          done = _yield$iterator$next.done;
+        if (done) {
+          readable.push(null);
+        } else if (readable.push(yield value)) {
+          next();
+        } else {
+          reading = false;
+        }
+      } catch (err) {
+        readable.destroy(err);
+      }
+    });
+    return _next2.apply(this, arguments);
+  }
+  return readable;
+}
+module.exports = from;
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/pipeline.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/pipeline.js
new file mode 100644
index 0000000..e6f3924
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/pipeline.js
@@ -0,0 +1,86 @@
+// Ported from https://github.com/mafintosh/pump with
+// permission from the author, Mathias Buus (@mafintosh).
+
+'use strict';
+
+var eos;
+function once(callback) {
+  var called = false;
+  return function () {
+    if (called) return;
+    called = true;
+    callback.apply(void 0, arguments);
+  };
+}
+var _require$codes = require('../../../errors').codes,
+  ERR_MISSING_ARGS = _require$codes.ERR_MISSING_ARGS,
+  ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED;
+function noop(err) {
+  // Rethrow the error if it exists to avoid swallowing it
+  if (err) throw err;
+}
+function isRequest(stream) {
+  return stream.setHeader && typeof stream.abort === 'function';
+}
+function destroyer(stream, reading, writing, callback) {
+  callback = once(callback);
+  var closed = false;
+  stream.on('close', function () {
+    closed = true;
+  });
+  if (eos === undefined) eos = require('./end-of-stream');
+  eos(stream, {
+    readable: reading,
+    writable: writing
+  }, function (err) {
+    if (err) return callback(err);
+    closed = true;
+    callback();
+  });
+  var destroyed = false;
+  return function (err) {
+    if (closed) return;
+    if (destroyed) return;
+    destroyed = true;
+
+    // request.destroy just do .end - .abort is what we want
+    if (isRequest(stream)) return stream.abort();
+    if (typeof stream.destroy === 'function') return stream.destroy();
+    callback(err || new ERR_STREAM_DESTROYED('pipe'));
+  };
+}
+function call(fn) {
+  fn();
+}
+function pipe(from, to) {
+  return from.pipe(to);
+}
+function popCallback(streams) {
+  if (!streams.length) return noop;
+  if (typeof streams[streams.length - 1] !== 'function') return noop;
+  return streams.pop();
+}
+function pipeline() {
+  for (var _len = arguments.length, streams = new Array(_len), _key = 0; _key < _len; _key++) {
+    streams[_key] = arguments[_key];
+  }
+  var callback = popCallback(streams);
+  if (Array.isArray(streams[0])) streams = streams[0];
+  if (streams.length < 2) {
+    throw new ERR_MISSING_ARGS('streams');
+  }
+  var error;
+  var destroys = streams.map(function (stream, i) {
+    var reading = i < streams.length - 1;
+    var writing = i > 0;
+    return destroyer(stream, reading, writing, function (err) {
+      if (!error) error = err;
+      if (err) destroys.forEach(call);
+      if (reading) return;
+      destroys.forEach(call);
+      callback(error);
+    });
+  });
+  return streams.reduce(pipe);
+}
+module.exports = pipeline;
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/state.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/state.js
new file mode 100644
index 0000000..3fbf892
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/state.js
@@ -0,0 +1,22 @@
+'use strict';
+
+var ERR_INVALID_OPT_VALUE = require('../../../errors').codes.ERR_INVALID_OPT_VALUE;
+function highWaterMarkFrom(options, isDuplex, duplexKey) {
+  return options.highWaterMark != null ? options.highWaterMark : isDuplex ? options[duplexKey] : null;
+}
+function getHighWaterMark(state, options, duplexKey, isDuplex) {
+  var hwm = highWaterMarkFrom(options, isDuplex, duplexKey);
+  if (hwm != null) {
+    if (!(isFinite(hwm) && Math.floor(hwm) === hwm) || hwm < 0) {
+      var name = isDuplex ? duplexKey : 'highWaterMark';
+      throw new ERR_INVALID_OPT_VALUE(name, hwm);
+    }
+    return Math.floor(hwm);
+  }
+
+  // Default value
+  return state.objectMode ? 16 : 16 * 1024;
+}
+module.exports = {
+  getHighWaterMark: getHighWaterMark
+};
\ No newline at end of file
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/stream-browser.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/stream-browser.js
new file mode 100644
index 0000000..9332a3f
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/stream-browser.js
@@ -0,0 +1 @@
+module.exports = require('events').EventEmitter;
diff --git a/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/stream.js b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/stream.js
new file mode 100644
index 0000000..ce2ad5b
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/lib/internal/streams/stream.js
@@ -0,0 +1 @@
+module.exports = require('stream');
diff --git a/server/node_modules/bl/node_modules/readable-stream/package.json b/server/node_modules/bl/node_modules/readable-stream/package.json
new file mode 100644
index 0000000..ade59e7
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/package.json
@@ -0,0 +1,68 @@
+{
+  "name": "readable-stream",
+  "version": "3.6.2",
+  "description": "Streams3, a user-land copy of the stream library from Node.js",
+  "main": "readable.js",
+  "engines": {
+    "node": ">= 6"
+  },
+  "dependencies": {
+    "inherits": "^2.0.3",
+    "string_decoder": "^1.1.1",
+    "util-deprecate": "^1.0.1"
+  },
+  "devDependencies": {
+    "@babel/cli": "^7.2.0",
+    "@babel/core": "^7.2.0",
+    "@babel/polyfill": "^7.0.0",
+    "@babel/preset-env": "^7.2.0",
+    "airtap": "0.0.9",
+    "assert": "^1.4.0",
+    "bl": "^2.0.0",
+    "deep-strict-equal": "^0.2.0",
+    "events.once": "^2.0.2",
+    "glob": "^7.1.2",
+    "gunzip-maybe": "^1.4.1",
+    "hyperquest": "^2.1.3",
+    "lolex": "^2.6.0",
+    "nyc": "^11.0.0",
+    "pump": "^3.0.0",
+    "rimraf": "^2.6.2",
+    "tap": "^12.0.0",
+    "tape": "^4.9.0",
+    "tar-fs": "^1.16.2",
+    "util-promisify": "^2.1.0"
+  },
+  "scripts": {
+    "test": "tap -J --no-esm test/parallel/*.js test/ours/*.js",
+    "ci": "TAP=1 tap --no-esm test/parallel/*.js test/ours/*.js | tee test.tap",
+    "test-browsers": "airtap --sauce-connect --loopback airtap.local -- test/browser.js",
+    "test-browser-local": "airtap --open --local -- test/browser.js",
+    "cover": "nyc npm test",
+    "report": "nyc report --reporter=lcov",
+    "update-browser-errors": "babel -o errors-browser.js errors.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/nodejs/readable-stream"
+  },
+  "keywords": [
+    "readable",
+    "stream",
+    "pipe"
+  ],
+  "browser": {
+    "util": false,
+    "worker_threads": false,
+    "./errors": "./errors-browser.js",
+    "./readable.js": "./readable-browser.js",
+    "./lib/internal/streams/from.js": "./lib/internal/streams/from-browser.js",
+    "./lib/internal/streams/stream.js": "./lib/internal/streams/stream-browser.js"
+  },
+  "nyc": {
+    "include": [
+      "lib/**.js"
+    ]
+  },
+  "license": "MIT"
+}
diff --git a/server/node_modules/bl/node_modules/readable-stream/readable-browser.js b/server/node_modules/bl/node_modules/readable-stream/readable-browser.js
new file mode 100644
index 0000000..adbf60d
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/readable-browser.js
@@ -0,0 +1,9 @@
+exports = module.exports = require('./lib/_stream_readable.js');
+exports.Stream = exports;
+exports.Readable = exports;
+exports.Writable = require('./lib/_stream_writable.js');
+exports.Duplex = require('./lib/_stream_duplex.js');
+exports.Transform = require('./lib/_stream_transform.js');
+exports.PassThrough = require('./lib/_stream_passthrough.js');
+exports.finished = require('./lib/internal/streams/end-of-stream.js');
+exports.pipeline = require('./lib/internal/streams/pipeline.js');
diff --git a/server/node_modules/bl/node_modules/readable-stream/readable.js b/server/node_modules/bl/node_modules/readable-stream/readable.js
new file mode 100644
index 0000000..9e0ca12
--- /dev/null
+++ b/server/node_modules/bl/node_modules/readable-stream/readable.js
@@ -0,0 +1,16 @@
+var Stream = require('stream');
+if (process.env.READABLE_STREAM === 'disable' && Stream) {
+  module.exports = Stream.Readable;
+  Object.assign(module.exports, Stream);
+  module.exports.Stream = Stream;
+} else {
+  exports = module.exports = require('./lib/_stream_readable.js');
+  exports.Stream = Stream || exports;
+  exports.Readable = exports;
+  exports.Writable = require('./lib/_stream_writable.js');
+  exports.Duplex = require('./lib/_stream_duplex.js');
+  exports.Transform = require('./lib/_stream_transform.js');
+  exports.PassThrough = require('./lib/_stream_passthrough.js');
+  exports.finished = require('./lib/internal/streams/end-of-stream.js');
+  exports.pipeline = require('./lib/internal/streams/pipeline.js');
+}
diff --git a/server/node_modules/bl/package.json b/server/node_modules/bl/package.json
new file mode 100644
index 0000000..3b2be3f
--- /dev/null
+++ b/server/node_modules/bl/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "bl",
+  "version": "4.1.0",
+  "description": "Buffer List: collect buffers and access with a standard readable Buffer interface, streamable too!",
+  "license": "MIT",
+  "main": "bl.js",
+  "scripts": {
+    "lint": "standard *.js test/*.js",
+    "test": "npm run lint && node test/test.js | faucet"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/rvagg/bl.git"
+  },
+  "homepage": "https://github.com/rvagg/bl",
+  "authors": [
+    "Rod Vagg <rod@vagg.org> (https://github.com/rvagg)",
+    "Matteo Collina <matteo.collina@gmail.com> (https://github.com/mcollina)",
+    "Jarett Cruger <jcrugzz@gmail.com> (https://github.com/jcrugzz)"
+  ],
+  "keywords": [
+    "buffer",
+    "buffers",
+    "stream",
+    "awesomesauce"
+  ],
+  "dependencies": {
+    "buffer": "^5.5.0",
+    "inherits": "^2.0.4",
+    "readable-stream": "^3.4.0"
+  },
+  "devDependencies": {
+    "faucet": "~0.0.1",
+    "standard": "^14.3.0",
+    "tape": "^4.11.0"
+  }
+}
diff --git a/server/node_modules/bl/test/convert.js b/server/node_modules/bl/test/convert.js
new file mode 100644
index 0000000..9f3e235
--- /dev/null
+++ b/server/node_modules/bl/test/convert.js
@@ -0,0 +1,21 @@
+'use strict'
+
+const tape = require('tape')
+const { BufferList, BufferListStream } = require('../')
+const { Buffer } = require('buffer')
+
+tape('convert from BufferList to BufferListStream', (t) => {
+  const data = Buffer.from(`TEST-${Date.now()}`)
+  const bl = new BufferList(data)
+  const bls = new BufferListStream(bl)
+  t.ok(bl.slice().equals(bls.slice()))
+  t.end()
+})
+
+tape('convert from BufferListStream to BufferList', (t) => {
+  const data = Buffer.from(`TEST-${Date.now()}`)
+  const bls = new BufferListStream(data)
+  const bl = new BufferList(bls)
+  t.ok(bl.slice().equals(bls.slice()))
+  t.end()
+})
diff --git a/server/node_modules/bl/test/indexOf.js b/server/node_modules/bl/test/indexOf.js
new file mode 100644
index 0000000..62dcb01
--- /dev/null
+++ b/server/node_modules/bl/test/indexOf.js
@@ -0,0 +1,492 @@
+'use strict'
+
+const tape = require('tape')
+const BufferList = require('../')
+const { Buffer } = require('buffer')
+
+tape('indexOf single byte needle', (t) => {
+  const bl = new BufferList(['abcdefg', 'abcdefg', '12345'])
+
+  t.equal(bl.indexOf('e'), 4)
+  t.equal(bl.indexOf('e', 5), 11)
+  t.equal(bl.indexOf('e', 12), -1)
+  t.equal(bl.indexOf('5'), 18)
+
+  t.end()
+})
+
+tape('indexOf multiple byte needle', (t) => {
+  const bl = new BufferList(['abcdefg', 'abcdefg'])
+
+  t.equal(bl.indexOf('ef'), 4)
+  t.equal(bl.indexOf('ef', 5), 11)
+
+  t.end()
+})
+
+tape('indexOf multiple byte needles across buffer boundaries', (t) => {
+  const bl = new BufferList(['abcdefg', 'abcdefg'])
+
+  t.equal(bl.indexOf('fgabc'), 5)
+
+  t.end()
+})
+
+tape('indexOf takes a Uint8Array search', (t) => {
+  const bl = new BufferList(['abcdefg', 'abcdefg'])
+  const search = new Uint8Array([102, 103, 97, 98, 99]) // fgabc
+
+  t.equal(bl.indexOf(search), 5)
+
+  t.end()
+})
+
+tape('indexOf takes a buffer list search', (t) => {
+  const bl = new BufferList(['abcdefg', 'abcdefg'])
+  const search = new BufferList('fgabc')
+
+  t.equal(bl.indexOf(search), 5)
+
+  t.end()
+})
+
+tape('indexOf a zero byte needle', (t) => {
+  const b = new BufferList('abcdef')
+  const bufEmpty = Buffer.from('')
+
+  t.equal(b.indexOf(''), 0)
+  t.equal(b.indexOf('', 1), 1)
+  t.equal(b.indexOf('', b.length + 1), b.length)
+  t.equal(b.indexOf('', Infinity), b.length)
+  t.equal(b.indexOf(bufEmpty), 0)
+  t.equal(b.indexOf(bufEmpty, 1), 1)
+  t.equal(b.indexOf(bufEmpty, b.length + 1), b.length)
+  t.equal(b.indexOf(bufEmpty, Infinity), b.length)
+
+  t.end()
+})
+
+tape('indexOf buffers smaller and larger than the needle', (t) => {
+  const bl = new BufferList(['abcdefg', 'a', 'bcdefg', 'a', 'bcfgab'])
+
+  t.equal(bl.indexOf('fgabc'), 5)
+  t.equal(bl.indexOf('fgabc', 6), 12)
+  t.equal(bl.indexOf('fgabc', 13), -1)
+
+  t.end()
+})
+
+// only present in node 6+
+;(process.version.substr(1).split('.')[0] >= 6) && tape('indexOf latin1 and binary encoding', (t) => {
+  const b = new BufferList('abcdef')
+
+  // test latin1 encoding
+  t.equal(
+    new BufferList(Buffer.from(b.toString('latin1'), 'latin1'))
+      .indexOf('d', 0, 'latin1'),
+    3
+  )
+  t.equal(
+    new BufferList(Buffer.from(b.toString('latin1'), 'latin1'))
+      .indexOf(Buffer.from('d', 'latin1'), 0, 'latin1'),
+    3
+  )
+  t.equal(
+    new BufferList(Buffer.from('aa\u00e8aa', 'latin1'))
+      .indexOf('\u00e8', 'latin1'),
+    2
+  )
+  t.equal(
+    new BufferList(Buffer.from('\u00e8', 'latin1'))
+      .indexOf('\u00e8', 'latin1'),
+    0
+  )
+  t.equal(
+    new BufferList(Buffer.from('\u00e8', 'latin1'))
+      .indexOf(Buffer.from('\u00e8', 'latin1'), 'latin1'),
+    0
+  )
+
+  // test binary encoding
+  t.equal(
+    new BufferList(Buffer.from(b.toString('binary'), 'binary'))
+      .indexOf('d', 0, 'binary'),
+    3
+  )
+  t.equal(
+    new BufferList(Buffer.from(b.toString('binary'), 'binary'))
+      .indexOf(Buffer.from('d', 'binary'), 0, 'binary'),
+    3
+  )
+  t.equal(
+    new BufferList(Buffer.from('aa\u00e8aa', 'binary'))
+      .indexOf('\u00e8', 'binary'),
+    2
+  )
+  t.equal(
+    new BufferList(Buffer.from('\u00e8', 'binary'))
+      .indexOf('\u00e8', 'binary'),
+    0
+  )
+  t.equal(
+    new BufferList(Buffer.from('\u00e8', 'binary'))
+      .indexOf(Buffer.from('\u00e8', 'binary'), 'binary'),
+    0
+  )
+
+  t.end()
+})
+
+tape('indexOf the entire nodejs10 buffer test suite', (t) => {
+  const b = new BufferList('abcdef')
+  const bufA = Buffer.from('a')
+  const bufBc = Buffer.from('bc')
+  const bufF = Buffer.from('f')
+  const bufZ = Buffer.from('z')
+
+  const stringComparison = 'abcdef'
+
+  t.equal(b.indexOf('a'), 0)
+  t.equal(b.indexOf('a', 1), -1)
+  t.equal(b.indexOf('a', -1), -1)
+  t.equal(b.indexOf('a', -4), -1)
+  t.equal(b.indexOf('a', -b.length), 0)
+  t.equal(b.indexOf('a', NaN), 0)
+  t.equal(b.indexOf('a', -Infinity), 0)
+  t.equal(b.indexOf('a', Infinity), -1)
+  t.equal(b.indexOf('bc'), 1)
+  t.equal(b.indexOf('bc', 2), -1)
+  t.equal(b.indexOf('bc', -1), -1)
+  t.equal(b.indexOf('bc', -3), -1)
+  t.equal(b.indexOf('bc', -5), 1)
+  t.equal(b.indexOf('bc', NaN), 1)
+  t.equal(b.indexOf('bc', -Infinity), 1)
+  t.equal(b.indexOf('bc', Infinity), -1)
+  t.equal(b.indexOf('f'), b.length - 1)
+  t.equal(b.indexOf('z'), -1)
+
+  // empty search tests
+  t.equal(b.indexOf(bufA), 0)
+  t.equal(b.indexOf(bufA, 1), -1)
+  t.equal(b.indexOf(bufA, -1), -1)
+  t.equal(b.indexOf(bufA, -4), -1)
+  t.equal(b.indexOf(bufA, -b.length), 0)
+  t.equal(b.indexOf(bufA, NaN), 0)
+  t.equal(b.indexOf(bufA, -Infinity), 0)
+  t.equal(b.indexOf(bufA, Infinity), -1)
+  t.equal(b.indexOf(bufBc), 1)
+  t.equal(b.indexOf(bufBc, 2), -1)
+  t.equal(b.indexOf(bufBc, -1), -1)
+  t.equal(b.indexOf(bufBc, -3), -1)
+  t.equal(b.indexOf(bufBc, -5), 1)
+  t.equal(b.indexOf(bufBc, NaN), 1)
+  t.equal(b.indexOf(bufBc, -Infinity), 1)
+  t.equal(b.indexOf(bufBc, Infinity), -1)
+  t.equal(b.indexOf(bufF), b.length - 1)
+  t.equal(b.indexOf(bufZ), -1)
+  t.equal(b.indexOf(0x61), 0)
+  t.equal(b.indexOf(0x61, 1), -1)
+  t.equal(b.indexOf(0x61, -1), -1)
+  t.equal(b.indexOf(0x61, -4), -1)
+  t.equal(b.indexOf(0x61, -b.length), 0)
+  t.equal(b.indexOf(0x61, NaN), 0)
+  t.equal(b.indexOf(0x61, -Infinity), 0)
+  t.equal(b.indexOf(0x61, Infinity), -1)
+  t.equal(b.indexOf(0x0), -1)
+
+  // test offsets
+  t.equal(b.indexOf('d', 2), 3)
+  t.equal(b.indexOf('f', 5), 5)
+  t.equal(b.indexOf('f', -1), 5)
+  t.equal(b.indexOf('f', 6), -1)
+
+  t.equal(b.indexOf(Buffer.from('d'), 2), 3)
+  t.equal(b.indexOf(Buffer.from('f'), 5), 5)
+  t.equal(b.indexOf(Buffer.from('f'), -1), 5)
+  t.equal(b.indexOf(Buffer.from('f'), 6), -1)
+
+  t.equal(Buffer.from('ff').indexOf(Buffer.from('f'), 1, 'ucs2'), -1)
+
+  // test invalid and uppercase encoding
+  t.equal(b.indexOf('b', 'utf8'), 1)
+  t.equal(b.indexOf('b', 'UTF8'), 1)
+  t.equal(b.indexOf('62', 'HEX'), 1)
+  t.throws(() => b.indexOf('bad', 'enc'), TypeError)
+
+  // test hex encoding
+  t.equal(
+    Buffer.from(b.toString('hex'), 'hex')
+      .indexOf('64', 0, 'hex'),
+    3
+  )
+  t.equal(
+    Buffer.from(b.toString('hex'), 'hex')
+      .indexOf(Buffer.from('64', 'hex'), 0, 'hex'),
+    3
+  )
+
+  // test base64 encoding
+  t.equal(
+    Buffer.from(b.toString('base64'), 'base64')
+      .indexOf('ZA==', 0, 'base64'),
+    3
+  )
+  t.equal(
+    Buffer.from(b.toString('base64'), 'base64')
+      .indexOf(Buffer.from('ZA==', 'base64'), 0, 'base64'),
+    3
+  )
+
+  // test ascii encoding
+  t.equal(
+    Buffer.from(b.toString('ascii'), 'ascii')
+      .indexOf('d', 0, 'ascii'),
+    3
+  )
+  t.equal(
+    Buffer.from(b.toString('ascii'), 'ascii')
+      .indexOf(Buffer.from('d', 'ascii'), 0, 'ascii'),
+    3
+  )
+
+  // test optional offset with passed encoding
+  t.equal(Buffer.from('aaaa0').indexOf('30', 'hex'), 4)
+  t.equal(Buffer.from('aaaa00a').indexOf('3030', 'hex'), 4)
+
+  {
+    // test usc2 encoding
+    const twoByteString = Buffer.from('\u039a\u0391\u03a3\u03a3\u0395', 'ucs2')
+
+    t.equal(8, twoByteString.indexOf('\u0395', 4, 'ucs2'))
+    t.equal(6, twoByteString.indexOf('\u03a3', -4, 'ucs2'))
+    t.equal(4, twoByteString.indexOf('\u03a3', -6, 'ucs2'))
+    t.equal(4, twoByteString.indexOf(
+      Buffer.from('\u03a3', 'ucs2'), -6, 'ucs2'))
+    t.equal(-1, twoByteString.indexOf('\u03a3', -2, 'ucs2'))
+  }
+
+  const mixedByteStringUcs2 =
+      Buffer.from('\u039a\u0391abc\u03a3\u03a3\u0395', 'ucs2')
+
+  t.equal(6, mixedByteStringUcs2.indexOf('bc', 0, 'ucs2'))
+  t.equal(10, mixedByteStringUcs2.indexOf('\u03a3', 0, 'ucs2'))
+  t.equal(-1, mixedByteStringUcs2.indexOf('\u0396', 0, 'ucs2'))
+
+  t.equal(
+    6, mixedByteStringUcs2.indexOf(Buffer.from('bc', 'ucs2'), 0, 'ucs2'))
+  t.equal(
+    10, mixedByteStringUcs2.indexOf(Buffer.from('\u03a3', 'ucs2'), 0, 'ucs2'))
+  t.equal(
+    -1, mixedByteStringUcs2.indexOf(Buffer.from('\u0396', 'ucs2'), 0, 'ucs2'))
+
+  {
+    const twoByteString = Buffer.from('\u039a\u0391\u03a3\u03a3\u0395', 'ucs2')
+
+    // Test single char pattern
+    t.equal(0, twoByteString.indexOf('\u039a', 0, 'ucs2'))
+    let index = twoByteString.indexOf('\u0391', 0, 'ucs2')
+    t.equal(2, index, `Alpha - at index ${index}`)
+    index = twoByteString.indexOf('\u03a3', 0, 'ucs2')
+    t.equal(4, index, `First Sigma - at index ${index}`)
+    index = twoByteString.indexOf('\u03a3', 6, 'ucs2')
+    t.equal(6, index, `Second Sigma - at index ${index}`)
+    index = twoByteString.indexOf('\u0395', 0, 'ucs2')
+    t.equal(8, index, `Epsilon - at index ${index}`)
+    index = twoByteString.indexOf('\u0392', 0, 'ucs2')
+    t.equal(-1, index, `Not beta - at index ${index}`)
+
+    // Test multi-char pattern
+    index = twoByteString.indexOf('\u039a\u0391', 0, 'ucs2')
+    t.equal(0, index, `Lambda Alpha - at index ${index}`)
+    index = twoByteString.indexOf('\u0391\u03a3', 0, 'ucs2')
+    t.equal(2, index, `Alpha Sigma - at index ${index}`)
+    index = twoByteString.indexOf('\u03a3\u03a3', 0, 'ucs2')
+    t.equal(4, index, `Sigma Sigma - at index ${index}`)
+    index = twoByteString.indexOf('\u03a3\u0395', 0, 'ucs2')
+    t.equal(6, index, `Sigma Epsilon - at index ${index}`)
+  }
+
+  const mixedByteStringUtf8 = Buffer.from('\u039a\u0391abc\u03a3\u03a3\u0395')
+
+  t.equal(5, mixedByteStringUtf8.indexOf('bc'))
+  t.equal(5, mixedByteStringUtf8.indexOf('bc', 5))
+  t.equal(5, mixedByteStringUtf8.indexOf('bc', -8))
+  t.equal(7, mixedByteStringUtf8.indexOf('\u03a3'))
+  t.equal(-1, mixedByteStringUtf8.indexOf('\u0396'))
+
+  // Test complex string indexOf algorithms. Only trigger for long strings.
+  // Long string that isn't a simple repeat of a shorter string.
+  let longString = 'A'
+  for (let i = 66; i < 76; i++) { // from 'B' to 'K'
+    longString = longString + String.fromCharCode(i) + longString
+  }
+
+  const longBufferString = Buffer.from(longString)
+
+  // pattern of 15 chars, repeated every 16 chars in long
+  let pattern = 'ABACABADABACABA'
+  for (let i = 0; i < longBufferString.length - pattern.length; i += 7) {
+    const index = longBufferString.indexOf(pattern, i)
+    t.equal((i + 15) & ~0xf, index,
+      `Long ABACABA...-string at index ${i}`)
+  }
+
+  let index = longBufferString.indexOf('AJABACA')
+  t.equal(510, index, `Long AJABACA, First J - at index ${index}`)
+  index = longBufferString.indexOf('AJABACA', 511)
+  t.equal(1534, index, `Long AJABACA, Second J - at index ${index}`)
+
+  pattern = 'JABACABADABACABA'
+  index = longBufferString.indexOf(pattern)
+  t.equal(511, index, `Long JABACABA..., First J - at index ${index}`)
+  index = longBufferString.indexOf(pattern, 512)
+  t.equal(
+    1535, index, `Long JABACABA..., Second J - at index ${index}`)
+
+  // Search for a non-ASCII string in a pure ASCII string.
+  const asciiString = Buffer.from(
+    'somethingnotatallsinisterwhichalsoworks')
+  t.equal(-1, asciiString.indexOf('\x2061'))
+  t.equal(3, asciiString.indexOf('eth', 0))
+
+  // Search in string containing many non-ASCII chars.
+  const allCodePoints = []
+  for (let i = 0; i < 65536; i++) {
+    allCodePoints[i] = i
+  }
+
+  const allCharsString = String.fromCharCode.apply(String, allCodePoints)
+  const allCharsBufferUtf8 = Buffer.from(allCharsString)
+  const allCharsBufferUcs2 = Buffer.from(allCharsString, 'ucs2')
+
+  // Search for string long enough to trigger complex search with ASCII pattern
+  // and UC16 subject.
+  t.equal(-1, allCharsBufferUtf8.indexOf('notfound'))
+  t.equal(-1, allCharsBufferUcs2.indexOf('notfound'))
+
+  // Needle is longer than haystack, but only because it's encoded as UTF-16
+  t.equal(Buffer.from('aaaa').indexOf('a'.repeat(4), 'ucs2'), -1)
+
+  t.equal(Buffer.from('aaaa').indexOf('a'.repeat(4), 'utf8'), 0)
+  t.equal(Buffer.from('aaaa').indexOf('你好', 'ucs2'), -1)
+
+  // Haystack has odd length, but the needle is UCS2.
+  t.equal(Buffer.from('aaaaa').indexOf('b', 'ucs2'), -1)
+
+  {
+    // Find substrings in Utf8.
+    const lengths = [1, 3, 15] // Single char, simple and complex.
+    const indices = [0x5, 0x60, 0x400, 0x680, 0x7ee, 0xFF02, 0x16610, 0x2f77b]
+    for (let lengthIndex = 0; lengthIndex < lengths.length; lengthIndex++) {
+      for (let i = 0; i < indices.length; i++) {
+        const index = indices[i]
+        let length = lengths[lengthIndex]
+
+        if (index + length > 0x7F) {
+          length = 2 * length
+        }
+
+        if (index + length > 0x7FF) {
+          length = 3 * length
+        }
+
+        if (index + length > 0xFFFF) {
+          length = 4 * length
+        }
+
+        const patternBufferUtf8 = allCharsBufferUtf8.slice(index, index + length)
+        t.equal(index, allCharsBufferUtf8.indexOf(patternBufferUtf8))
+
+        const patternStringUtf8 = patternBufferUtf8.toString()
+        t.equal(index, allCharsBufferUtf8.indexOf(patternStringUtf8))
+      }
+    }
+  }
+
+  {
+    // Find substrings in Usc2.
+    const lengths = [2, 4, 16] // Single char, simple and complex.
+    const indices = [0x5, 0x65, 0x105, 0x205, 0x285, 0x2005, 0x2085, 0xfff0]
+
+    for (let lengthIndex = 0; lengthIndex < lengths.length; lengthIndex++) {
+      for (let i = 0; i < indices.length; i++) {
+        const index = indices[i] * 2
+        const length = lengths[lengthIndex]
+
+        const patternBufferUcs2 =
+            allCharsBufferUcs2.slice(index, index + length)
+        t.equal(
+          index, allCharsBufferUcs2.indexOf(patternBufferUcs2, 0, 'ucs2'))
+
+        const patternStringUcs2 = patternBufferUcs2.toString('ucs2')
+        t.equal(
+          index, allCharsBufferUcs2.indexOf(patternStringUcs2, 0, 'ucs2'))
+      }
+    }
+  }
+
+  [
+    () => {},
+    {},
+    []
+  ].forEach((val) => {
+    t.throws(() => b.indexOf(val), TypeError, `"${JSON.stringify(val)}" should throw`)
+  })
+
+  // Test weird offset arguments.
+  // The following offsets coerce to NaN or 0, searching the whole Buffer
+  t.equal(b.indexOf('b', undefined), 1)
+  t.equal(b.indexOf('b', {}), 1)
+  t.equal(b.indexOf('b', 0), 1)
+  t.equal(b.indexOf('b', null), 1)
+  t.equal(b.indexOf('b', []), 1)
+
+  // The following offset coerces to 2, in other words +[2] === 2
+  t.equal(b.indexOf('b', [2]), -1)
+
+  // Behavior should match String.indexOf()
+  t.equal(
+    b.indexOf('b', undefined),
+    stringComparison.indexOf('b', undefined))
+  t.equal(
+    b.indexOf('b', {}),
+    stringComparison.indexOf('b', {}))
+  t.equal(
+    b.indexOf('b', 0),
+    stringComparison.indexOf('b', 0))
+  t.equal(
+    b.indexOf('b', null),
+    stringComparison.indexOf('b', null))
+  t.equal(
+    b.indexOf('b', []),
+    stringComparison.indexOf('b', []))
+  t.equal(
+    b.indexOf('b', [2]),
+    stringComparison.indexOf('b', [2]))
+
+  // test truncation of Number arguments to uint8
+  {
+    const buf = Buffer.from('this is a test')
+
+    t.equal(buf.indexOf(0x6973), 3)
+    t.equal(buf.indexOf(0x697320), 4)
+    t.equal(buf.indexOf(0x69732069), 2)
+    t.equal(buf.indexOf(0x697374657374), 0)
+    t.equal(buf.indexOf(0x69737374), 0)
+    t.equal(buf.indexOf(0x69737465), 11)
+    t.equal(buf.indexOf(0x69737465), 11)
+    t.equal(buf.indexOf(-140), 0)
+    t.equal(buf.indexOf(-152), 1)
+    t.equal(buf.indexOf(0xff), -1)
+    t.equal(buf.indexOf(0xffff), -1)
+  }
+
+  // Test that Uint8Array arguments are okay.
+  {
+    const needle = new Uint8Array([0x66, 0x6f, 0x6f])
+    const haystack = new BufferList(Buffer.from('a foo b foo'))
+    t.equal(haystack.indexOf(needle), 2)
+  }
+
+  t.end()
+})
diff --git a/server/node_modules/bl/test/isBufferList.js b/server/node_modules/bl/test/isBufferList.js
new file mode 100644
index 0000000..9d895d5
--- /dev/null
+++ b/server/node_modules/bl/test/isBufferList.js
@@ -0,0 +1,32 @@
+'use strict'
+
+const tape = require('tape')
+const { BufferList, BufferListStream } = require('../')
+const { Buffer } = require('buffer')
+
+tape('isBufferList positives', (t) => {
+  t.ok(BufferList.isBufferList(new BufferList()))
+  t.ok(BufferList.isBufferList(new BufferListStream()))
+
+  t.end()
+})
+
+tape('isBufferList negatives', (t) => {
+  const types = [
+    null,
+    undefined,
+    NaN,
+    true,
+    false,
+    {},
+    [],
+    Buffer.alloc(0),
+    [Buffer.alloc(0)]
+  ]
+
+  for (const obj of types) {
+    t.notOk(BufferList.isBufferList(obj))
+  }
+
+  t.end()
+})
diff --git a/server/node_modules/bl/test/test.js b/server/node_modules/bl/test/test.js
new file mode 100644
index 0000000..e523d0c
--- /dev/null
+++ b/server/node_modules/bl/test/test.js
@@ -0,0 +1,869 @@
+'use strict'
+
+const tape = require('tape')
+const crypto = require('crypto')
+const fs = require('fs')
+const path = require('path')
+const BufferList = require('../')
+const { Buffer } = require('buffer')
+
+const encodings =
+      ('hex utf8 utf-8 ascii binary base64' +
+          (process.browser ? '' : ' ucs2 ucs-2 utf16le utf-16le')).split(' ')
+
+require('./indexOf')
+require('./isBufferList')
+require('./convert')
+
+tape('single bytes from single buffer', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('abcd'))
+
+  t.equal(bl.length, 4)
+  t.equal(bl.get(-1), undefined)
+  t.equal(bl.get(0), 97)
+  t.equal(bl.get(1), 98)
+  t.equal(bl.get(2), 99)
+  t.equal(bl.get(3), 100)
+  t.equal(bl.get(4), undefined)
+
+  t.end()
+})
+
+tape('single bytes from multiple buffers', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('abcd'))
+  bl.append(Buffer.from('efg'))
+  bl.append(Buffer.from('hi'))
+  bl.append(Buffer.from('j'))
+
+  t.equal(bl.length, 10)
+
+  t.equal(bl.get(0), 97)
+  t.equal(bl.get(1), 98)
+  t.equal(bl.get(2), 99)
+  t.equal(bl.get(3), 100)
+  t.equal(bl.get(4), 101)
+  t.equal(bl.get(5), 102)
+  t.equal(bl.get(6), 103)
+  t.equal(bl.get(7), 104)
+  t.equal(bl.get(8), 105)
+  t.equal(bl.get(9), 106)
+
+  t.end()
+})
+
+tape('multi bytes from single buffer', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('abcd'))
+
+  t.equal(bl.length, 4)
+
+  t.equal(bl.slice(0, 4).toString('ascii'), 'abcd')
+  t.equal(bl.slice(0, 3).toString('ascii'), 'abc')
+  t.equal(bl.slice(1, 4).toString('ascii'), 'bcd')
+  t.equal(bl.slice(-4, -1).toString('ascii'), 'abc')
+
+  t.end()
+})
+
+tape('multi bytes from single buffer (negative indexes)', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('buffer'))
+
+  t.equal(bl.length, 6)
+
+  t.equal(bl.slice(-6, -1).toString('ascii'), 'buffe')
+  t.equal(bl.slice(-6, -2).toString('ascii'), 'buff')
+  t.equal(bl.slice(-5, -2).toString('ascii'), 'uff')
+
+  t.end()
+})
+
+tape('multiple bytes from multiple buffers', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('abcd'))
+  bl.append(Buffer.from('efg'))
+  bl.append(Buffer.from('hi'))
+  bl.append(Buffer.from('j'))
+
+  t.equal(bl.length, 10)
+
+  t.equal(bl.slice(0, 10).toString('ascii'), 'abcdefghij')
+  t.equal(bl.slice(3, 10).toString('ascii'), 'defghij')
+  t.equal(bl.slice(3, 6).toString('ascii'), 'def')
+  t.equal(bl.slice(3, 8).toString('ascii'), 'defgh')
+  t.equal(bl.slice(5, 10).toString('ascii'), 'fghij')
+  t.equal(bl.slice(-7, -4).toString('ascii'), 'def')
+
+  t.end()
+})
+
+tape('multiple bytes from multiple buffer lists', function (t) {
+  const bl = new BufferList()
+
+  bl.append(new BufferList([Buffer.from('abcd'), Buffer.from('efg')]))
+  bl.append(new BufferList([Buffer.from('hi'), Buffer.from('j')]))
+
+  t.equal(bl.length, 10)
+
+  t.equal(bl.slice(0, 10).toString('ascii'), 'abcdefghij')
+
+  t.equal(bl.slice(3, 10).toString('ascii'), 'defghij')
+  t.equal(bl.slice(3, 6).toString('ascii'), 'def')
+  t.equal(bl.slice(3, 8).toString('ascii'), 'defgh')
+  t.equal(bl.slice(5, 10).toString('ascii'), 'fghij')
+
+  t.end()
+})
+
+// same data as previous test, just using nested constructors
+tape('multiple bytes from crazy nested buffer lists', function (t) {
+  const bl = new BufferList()
+
+  bl.append(new BufferList([
+    new BufferList([
+      new BufferList(Buffer.from('abc')),
+      Buffer.from('d'),
+      new BufferList(Buffer.from('efg'))
+    ]),
+    new BufferList([Buffer.from('hi')]),
+    new BufferList(Buffer.from('j'))
+  ]))
+
+  t.equal(bl.length, 10)
+
+  t.equal(bl.slice(0, 10).toString('ascii'), 'abcdefghij')
+
+  t.equal(bl.slice(3, 10).toString('ascii'), 'defghij')
+  t.equal(bl.slice(3, 6).toString('ascii'), 'def')
+  t.equal(bl.slice(3, 8).toString('ascii'), 'defgh')
+  t.equal(bl.slice(5, 10).toString('ascii'), 'fghij')
+
+  t.end()
+})
+
+tape('append accepts arrays of Buffers', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('abc'))
+  bl.append([Buffer.from('def')])
+  bl.append([Buffer.from('ghi'), Buffer.from('jkl')])
+  bl.append([Buffer.from('mnop'), Buffer.from('qrstu'), Buffer.from('vwxyz')])
+  t.equal(bl.length, 26)
+  t.equal(bl.slice().toString('ascii'), 'abcdefghijklmnopqrstuvwxyz')
+
+  t.end()
+})
+
+tape('append accepts arrays of Uint8Arrays', function (t) {
+  const bl = new BufferList()
+
+  bl.append(new Uint8Array([97, 98, 99]))
+  bl.append([Uint8Array.from([100, 101, 102])])
+  bl.append([new Uint8Array([103, 104, 105]), new Uint8Array([106, 107, 108])])
+  bl.append([new Uint8Array([109, 110, 111, 112]), new Uint8Array([113, 114, 115, 116, 117]), new Uint8Array([118, 119, 120, 121, 122])])
+  t.equal(bl.length, 26)
+  t.equal(bl.slice().toString('ascii'), 'abcdefghijklmnopqrstuvwxyz')
+
+  t.end()
+})
+
+tape('append accepts arrays of BufferLists', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('abc'))
+  bl.append([new BufferList('def')])
+  bl.append(new BufferList([Buffer.from('ghi'), new BufferList('jkl')]))
+  bl.append([Buffer.from('mnop'), new BufferList([Buffer.from('qrstu'), Buffer.from('vwxyz')])])
+  t.equal(bl.length, 26)
+  t.equal(bl.slice().toString('ascii'), 'abcdefghijklmnopqrstuvwxyz')
+
+  t.end()
+})
+
+tape('append chainable', function (t) {
+  const bl = new BufferList()
+
+  t.ok(bl.append(Buffer.from('abcd')) === bl)
+  t.ok(bl.append([Buffer.from('abcd')]) === bl)
+  t.ok(bl.append(new BufferList(Buffer.from('abcd'))) === bl)
+  t.ok(bl.append([new BufferList(Buffer.from('abcd'))]) === bl)
+
+  t.end()
+})
+
+tape('append chainable (test results)', function (t) {
+  const bl = new BufferList('abc')
+    .append([new BufferList('def')])
+    .append(new BufferList([Buffer.from('ghi'), new BufferList('jkl')]))
+    .append([Buffer.from('mnop'), new BufferList([Buffer.from('qrstu'), Buffer.from('vwxyz')])])
+
+  t.equal(bl.length, 26)
+  t.equal(bl.slice().toString('ascii'), 'abcdefghijklmnopqrstuvwxyz')
+
+  t.end()
+})
+
+tape('consuming from multiple buffers', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('abcd'))
+  bl.append(Buffer.from('efg'))
+  bl.append(Buffer.from('hi'))
+  bl.append(Buffer.from('j'))
+
+  t.equal(bl.length, 10)
+
+  t.equal(bl.slice(0, 10).toString('ascii'), 'abcdefghij')
+
+  bl.consume(3)
+  t.equal(bl.length, 7)
+  t.equal(bl.slice(0, 7).toString('ascii'), 'defghij')
+
+  bl.consume(2)
+  t.equal(bl.length, 5)
+  t.equal(bl.slice(0, 5).toString('ascii'), 'fghij')
+
+  bl.consume(1)
+  t.equal(bl.length, 4)
+  t.equal(bl.slice(0, 4).toString('ascii'), 'ghij')
+
+  bl.consume(1)
+  t.equal(bl.length, 3)
+  t.equal(bl.slice(0, 3).toString('ascii'), 'hij')
+
+  bl.consume(2)
+  t.equal(bl.length, 1)
+  t.equal(bl.slice(0, 1).toString('ascii'), 'j')
+
+  t.end()
+})
+
+tape('complete consumption', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('a'))
+  bl.append(Buffer.from('b'))
+
+  bl.consume(2)
+
+  t.equal(bl.length, 0)
+  t.equal(bl._bufs.length, 0)
+
+  t.end()
+})
+
+tape('test readUInt8 / readInt8', function (t) {
+  const buf1 = Buffer.alloc(1)
+  const buf2 = Buffer.alloc(3)
+  const buf3 = Buffer.alloc(3)
+  const bl = new BufferList()
+
+  buf1[0] = 0x1
+  buf2[1] = 0x3
+  buf2[2] = 0x4
+  buf3[0] = 0x23
+  buf3[1] = 0x42
+
+  bl.append(buf1)
+  bl.append(buf2)
+  bl.append(buf3)
+
+  t.equal(bl.readUInt8(), 0x1)
+  t.equal(bl.readUInt8(2), 0x3)
+  t.equal(bl.readInt8(2), 0x3)
+  t.equal(bl.readUInt8(3), 0x4)
+  t.equal(bl.readInt8(3), 0x4)
+  t.equal(bl.readUInt8(4), 0x23)
+  t.equal(bl.readInt8(4), 0x23)
+  t.equal(bl.readUInt8(5), 0x42)
+  t.equal(bl.readInt8(5), 0x42)
+
+  t.end()
+})
+
+tape('test readUInt16LE / readUInt16BE / readInt16LE / readInt16BE', function (t) {
+  const buf1 = Buffer.alloc(1)
+  const buf2 = Buffer.alloc(3)
+  const buf3 = Buffer.alloc(3)
+  const bl = new BufferList()
+
+  buf1[0] = 0x1
+  buf2[1] = 0x3
+  buf2[2] = 0x4
+  buf3[0] = 0x23
+  buf3[1] = 0x42
+
+  bl.append(buf1)
+  bl.append(buf2)
+  bl.append(buf3)
+
+  t.equal(bl.readUInt16BE(), 0x0100)
+  t.equal(bl.readUInt16LE(), 0x0001)
+  t.equal(bl.readUInt16BE(2), 0x0304)
+  t.equal(bl.readUInt16LE(2), 0x0403)
+  t.equal(bl.readInt16BE(2), 0x0304)
+  t.equal(bl.readInt16LE(2), 0x0403)
+  t.equal(bl.readUInt16BE(3), 0x0423)
+  t.equal(bl.readUInt16LE(3), 0x2304)
+  t.equal(bl.readInt16BE(3), 0x0423)
+  t.equal(bl.readInt16LE(3), 0x2304)
+  t.equal(bl.readUInt16BE(4), 0x2342)
+  t.equal(bl.readUInt16LE(4), 0x4223)
+  t.equal(bl.readInt16BE(4), 0x2342)
+  t.equal(bl.readInt16LE(4), 0x4223)
+
+  t.end()
+})
+
+tape('test readUInt32LE / readUInt32BE / readInt32LE / readInt32BE', function (t) {
+  const buf1 = Buffer.alloc(1)
+  const buf2 = Buffer.alloc(3)
+  const buf3 = Buffer.alloc(3)
+  const bl = new BufferList()
+
+  buf1[0] = 0x1
+  buf2[1] = 0x3
+  buf2[2] = 0x4
+  buf3[0] = 0x23
+  buf3[1] = 0x42
+
+  bl.append(buf1)
+  bl.append(buf2)
+  bl.append(buf3)
+
+  t.equal(bl.readUInt32BE(), 0x01000304)
+  t.equal(bl.readUInt32LE(), 0x04030001)
+  t.equal(bl.readUInt32BE(2), 0x03042342)
+  t.equal(bl.readUInt32LE(2), 0x42230403)
+  t.equal(bl.readInt32BE(2), 0x03042342)
+  t.equal(bl.readInt32LE(2), 0x42230403)
+
+  t.end()
+})
+
+tape('test readUIntLE / readUIntBE / readIntLE / readIntBE', function (t) {
+  const buf1 = Buffer.alloc(1)
+  const buf2 = Buffer.alloc(3)
+  const buf3 = Buffer.alloc(3)
+  const bl = new BufferList()
+
+  buf2[0] = 0x2
+  buf2[1] = 0x3
+  buf2[2] = 0x4
+  buf3[0] = 0x23
+  buf3[1] = 0x42
+  buf3[2] = 0x61
+
+  bl.append(buf1)
+  bl.append(buf2)
+  bl.append(buf3)
+
+  t.equal(bl.readUIntBE(1, 1), 0x02)
+  t.equal(bl.readUIntBE(1, 2), 0x0203)
+  t.equal(bl.readUIntBE(1, 3), 0x020304)
+  t.equal(bl.readUIntBE(1, 4), 0x02030423)
+  t.equal(bl.readUIntBE(1, 5), 0x0203042342)
+  t.equal(bl.readUIntBE(1, 6), 0x020304234261)
+  t.equal(bl.readUIntLE(1, 1), 0x02)
+  t.equal(bl.readUIntLE(1, 2), 0x0302)
+  t.equal(bl.readUIntLE(1, 3), 0x040302)
+  t.equal(bl.readUIntLE(1, 4), 0x23040302)
+  t.equal(bl.readUIntLE(1, 5), 0x4223040302)
+  t.equal(bl.readUIntLE(1, 6), 0x614223040302)
+  t.equal(bl.readIntBE(1, 1), 0x02)
+  t.equal(bl.readIntBE(1, 2), 0x0203)
+  t.equal(bl.readIntBE(1, 3), 0x020304)
+  t.equal(bl.readIntBE(1, 4), 0x02030423)
+  t.equal(bl.readIntBE(1, 5), 0x0203042342)
+  t.equal(bl.readIntBE(1, 6), 0x020304234261)
+  t.equal(bl.readIntLE(1, 1), 0x02)
+  t.equal(bl.readIntLE(1, 2), 0x0302)
+  t.equal(bl.readIntLE(1, 3), 0x040302)
+  t.equal(bl.readIntLE(1, 4), 0x23040302)
+  t.equal(bl.readIntLE(1, 5), 0x4223040302)
+  t.equal(bl.readIntLE(1, 6), 0x614223040302)
+
+  t.end()
+})
+
+tape('test readFloatLE / readFloatBE', function (t) {
+  const buf1 = Buffer.alloc(1)
+  const buf2 = Buffer.alloc(3)
+  const buf3 = Buffer.alloc(3)
+  const bl = new BufferList()
+
+  buf1[0] = 0x01
+  buf2[1] = 0x00
+  buf2[2] = 0x00
+  buf3[0] = 0x80
+  buf3[1] = 0x3f
+
+  bl.append(buf1)
+  bl.append(buf2)
+  bl.append(buf3)
+
+  const canonical = Buffer.concat([buf1, buf2, buf3])
+  t.equal(bl.readFloatLE(), canonical.readFloatLE())
+  t.equal(bl.readFloatBE(), canonical.readFloatBE())
+  t.equal(bl.readFloatLE(2), canonical.readFloatLE(2))
+  t.equal(bl.readFloatBE(2), canonical.readFloatBE(2))
+
+  t.end()
+})
+
+tape('test readDoubleLE / readDoubleBE', function (t) {
+  const buf1 = Buffer.alloc(1)
+  const buf2 = Buffer.alloc(3)
+  const buf3 = Buffer.alloc(10)
+  const bl = new BufferList()
+
+  buf1[0] = 0x01
+  buf2[1] = 0x55
+  buf2[2] = 0x55
+  buf3[0] = 0x55
+  buf3[1] = 0x55
+  buf3[2] = 0x55
+  buf3[3] = 0x55
+  buf3[4] = 0xd5
+  buf3[5] = 0x3f
+
+  bl.append(buf1)
+  bl.append(buf2)
+  bl.append(buf3)
+
+  const canonical = Buffer.concat([buf1, buf2, buf3])
+  t.equal(bl.readDoubleBE(), canonical.readDoubleBE())
+  t.equal(bl.readDoubleLE(), canonical.readDoubleLE())
+  t.equal(bl.readDoubleBE(2), canonical.readDoubleBE(2))
+  t.equal(bl.readDoubleLE(2), canonical.readDoubleLE(2))
+
+  t.end()
+})
+
+tape('test toString', function (t) {
+  const bl = new BufferList()
+
+  bl.append(Buffer.from('abcd'))
+  bl.append(Buffer.from('efg'))
+  bl.append(Buffer.from('hi'))
+  bl.append(Buffer.from('j'))
+
+  t.equal(bl.toString('ascii', 0, 10), 'abcdefghij')
+  t.equal(bl.toString('ascii', 3, 10), 'defghij')
+  t.equal(bl.toString('ascii', 3, 6), 'def')
+  t.equal(bl.toString('ascii', 3, 8), 'defgh')
+  t.equal(bl.toString('ascii', 5, 10), 'fghij')
+
+  t.end()
+})
+
+tape('test toString encoding', function (t) {
+  const bl = new BufferList()
+  const b = Buffer.from('abcdefghij\xff\x00')
+
+  bl.append(Buffer.from('abcd'))
+  bl.append(Buffer.from('efg'))
+  bl.append(Buffer.from('hi'))
+  bl.append(Buffer.from('j'))
+  bl.append(Buffer.from('\xff\x00'))
+
+  encodings.forEach(function (enc) {
+    t.equal(bl.toString(enc), b.toString(enc), enc)
+  })
+
+  t.end()
+})
+
+tape('uninitialized memory', function (t) {
+  const secret = crypto.randomBytes(256)
+  for (let i = 0; i < 1e6; i++) {
+    const clone = Buffer.from(secret)
+    const bl = new BufferList()
+    bl.append(Buffer.from('a'))
+    bl.consume(-1024)
+    const buf = bl.slice(1)
+    if (buf.indexOf(clone) !== -1) {
+      t.fail(`Match (at ${i})`)
+      break
+    }
+  }
+  t.end()
+})
+
+!process.browser && tape('test stream', function (t) {
+  const random = crypto.randomBytes(65534)
+
+  const bl = new BufferList((err, buf) => {
+    t.ok(Buffer.isBuffer(buf))
+    t.ok(err === null)
+    t.ok(random.equals(bl.slice()))
+    t.ok(random.equals(buf.slice()))
+
+    bl.pipe(fs.createWriteStream('/tmp/bl_test_rnd_out.dat'))
+      .on('close', function () {
+        const rndhash = crypto.createHash('md5').update(random).digest('hex')
+        const md5sum = crypto.createHash('md5')
+        const s = fs.createReadStream('/tmp/bl_test_rnd_out.dat')
+
+        s.on('data', md5sum.update.bind(md5sum))
+        s.on('end', function () {
+          t.equal(rndhash, md5sum.digest('hex'), 'woohoo! correct hash!')
+          t.end()
+        })
+      })
+  })
+
+  fs.writeFileSync('/tmp/bl_test_rnd.dat', random)
+  fs.createReadStream('/tmp/bl_test_rnd.dat').pipe(bl)
+})
+
+tape('instantiation with Buffer', function (t) {
+  const buf = crypto.randomBytes(1024)
+  const buf2 = crypto.randomBytes(1024)
+  let b = BufferList(buf)
+
+  t.equal(buf.toString('hex'), b.slice().toString('hex'), 'same buffer')
+  b = BufferList([buf, buf2])
+  t.equal(b.slice().toString('hex'), Buffer.concat([buf, buf2]).toString('hex'), 'same buffer')
+
+  t.end()
+})
+
+tape('test String appendage', function (t) {
+  const bl = new BufferList()
+  const b = Buffer.from('abcdefghij\xff\x00')
+
+  bl.append('abcd')
+  bl.append('efg')
+  bl.append('hi')
+  bl.append('j')
+  bl.append('\xff\x00')
+
+  encodings.forEach(function (enc) {
+    t.equal(bl.toString(enc), b.toString(enc))
+  })
+
+  t.end()
+})
+
+tape('test Number appendage', function (t) {
+  const bl = new BufferList()
+  const b = Buffer.from('1234567890')
+
+  bl.append(1234)
+  bl.append(567)
+  bl.append(89)
+  bl.append(0)
+
+  encodings.forEach(function (enc) {
+    t.equal(bl.toString(enc), b.toString(enc))
+  })
+
+  t.end()
+})
+
+tape('write nothing, should get empty buffer', function (t) {
+  t.plan(3)
+  BufferList(function (err, data) {
+    t.notOk(err, 'no error')
+    t.ok(Buffer.isBuffer(data), 'got a buffer')
+    t.equal(0, data.length, 'got a zero-length buffer')
+    t.end()
+  }).end()
+})
+
+tape('unicode string', function (t) {
+  t.plan(2)
+
+  const inp1 = '\u2600'
+  const inp2 = '\u2603'
+  const exp = inp1 + ' and ' + inp2
+  const bl = BufferList()
+
+  bl.write(inp1)
+  bl.write(' and ')
+  bl.write(inp2)
+  t.equal(exp, bl.toString())
+  t.equal(Buffer.from(exp).toString('hex'), bl.toString('hex'))
+})
+
+tape('should emit finish', function (t) {
+  const source = BufferList()
+  const dest = BufferList()
+
+  source.write('hello')
+  source.pipe(dest)
+
+  dest.on('finish', function () {
+    t.equal(dest.toString('utf8'), 'hello')
+    t.end()
+  })
+})
+
+tape('basic copy', function (t) {
+  const buf = crypto.randomBytes(1024)
+  const buf2 = Buffer.alloc(1024)
+  const b = BufferList(buf)
+
+  b.copy(buf2)
+  t.equal(b.slice().toString('hex'), buf2.toString('hex'), 'same buffer')
+
+  t.end()
+})
+
+tape('copy after many appends', function (t) {
+  const buf = crypto.randomBytes(512)
+  const buf2 = Buffer.alloc(1024)
+  const b = BufferList(buf)
+
+  b.append(buf)
+  b.copy(buf2)
+  t.equal(b.slice().toString('hex'), buf2.toString('hex'), 'same buffer')
+
+  t.end()
+})
+
+tape('copy at a precise position', function (t) {
+  const buf = crypto.randomBytes(1004)
+  const buf2 = Buffer.alloc(1024)
+  const b = BufferList(buf)
+
+  b.copy(buf2, 20)
+  t.equal(b.slice().toString('hex'), buf2.slice(20).toString('hex'), 'same buffer')
+
+  t.end()
+})
+
+tape('copy starting from a precise location', function (t) {
+  const buf = crypto.randomBytes(10)
+  const buf2 = Buffer.alloc(5)
+  const b = BufferList(buf)
+
+  b.copy(buf2, 0, 5)
+  t.equal(b.slice(5).toString('hex'), buf2.toString('hex'), 'same buffer')
+
+  t.end()
+})
+
+tape('copy in an interval', function (t) {
+  const rnd = crypto.randomBytes(10)
+  const b = BufferList(rnd) // put the random bytes there
+  const actual = Buffer.alloc(3)
+  const expected = Buffer.alloc(3)
+
+  rnd.copy(expected, 0, 5, 8)
+  b.copy(actual, 0, 5, 8)
+
+  t.equal(actual.toString('hex'), expected.toString('hex'), 'same buffer')
+
+  t.end()
+})
+
+tape('copy an interval between two buffers', function (t) {
+  const buf = crypto.randomBytes(10)
+  const buf2 = Buffer.alloc(10)
+  const b = BufferList(buf)
+
+  b.append(buf)
+  b.copy(buf2, 0, 5, 15)
+
+  t.equal(b.slice(5, 15).toString('hex'), buf2.toString('hex'), 'same buffer')
+
+  t.end()
+})
+
+tape('shallow slice across buffer boundaries', function (t) {
+  const bl = new BufferList(['First', 'Second', 'Third'])
+
+  t.equal(bl.shallowSlice(3, 13).toString(), 'stSecondTh')
+
+  t.end()
+})
+
+tape('shallow slice within single buffer', function (t) {
+  t.plan(2)
+
+  const bl = new BufferList(['First', 'Second', 'Third'])
+
+  t.equal(bl.shallowSlice(5, 10).toString(), 'Secon')
+  t.equal(bl.shallowSlice(7, 10).toString(), 'con')
+
+  t.end()
+})
+
+tape('shallow slice single buffer', function (t) {
+  t.plan(3)
+
+  const bl = new BufferList(['First', 'Second', 'Third'])
+
+  t.equal(bl.shallowSlice(0, 5).toString(), 'First')
+  t.equal(bl.shallowSlice(5, 11).toString(), 'Second')
+  t.equal(bl.shallowSlice(11, 16).toString(), 'Third')
+})
+
+tape('shallow slice with negative or omitted indices', function (t) {
+  t.plan(4)
+
+  const bl = new BufferList(['First', 'Second', 'Third'])
+
+  t.equal(bl.shallowSlice().toString(), 'FirstSecondThird')
+  t.equal(bl.shallowSlice(5).toString(), 'SecondThird')
+  t.equal(bl.shallowSlice(5, -3).toString(), 'SecondTh')
+  t.equal(bl.shallowSlice(-8).toString(), 'ondThird')
+})
+
+tape('shallow slice does not make a copy', function (t) {
+  t.plan(1)
+
+  const buffers = [Buffer.from('First'), Buffer.from('Second'), Buffer.from('Third')]
+  const bl = (new BufferList(buffers)).shallowSlice(5, -3)
+
+  buffers[1].fill('h')
+  buffers[2].fill('h')
+
+  t.equal(bl.toString(), 'hhhhhhhh')
+})
+
+tape('shallow slice with 0 length', function (t) {
+  t.plan(1)
+
+  const buffers = [Buffer.from('First'), Buffer.from('Second'), Buffer.from('Third')]
+  const bl = (new BufferList(buffers)).shallowSlice(0, 0)
+
+  t.equal(bl.length, 0)
+})
+
+tape('shallow slice with 0 length from middle', function (t) {
+  t.plan(1)
+
+  const buffers = [Buffer.from('First'), Buffer.from('Second'), Buffer.from('Third')]
+  const bl = (new BufferList(buffers)).shallowSlice(10, 10)
+
+  t.equal(bl.length, 0)
+})
+
+tape('duplicate', function (t) {
+  t.plan(2)
+
+  const bl = new BufferList('abcdefghij\xff\x00')
+  const dup = bl.duplicate()
+
+  t.equal(bl.prototype, dup.prototype)
+  t.equal(bl.toString('hex'), dup.toString('hex'))
+})
+
+tape('destroy no pipe', function (t) {
+  t.plan(2)
+
+  const bl = new BufferList('alsdkfja;lsdkfja;lsdk')
+
+  bl.destroy()
+
+  t.equal(bl._bufs.length, 0)
+  t.equal(bl.length, 0)
+})
+
+tape('destroy with error', function (t) {
+  t.plan(3)
+
+  const bl = new BufferList('alsdkfja;lsdkfja;lsdk')
+  const err = new Error('kaboom')
+
+  bl.destroy(err)
+  bl.on('error', function (_err) {
+    t.equal(_err, err)
+  })
+
+  t.equal(bl._bufs.length, 0)
+  t.equal(bl.length, 0)
+})
+
+!process.browser && tape('destroy with pipe before read end', function (t) {
+  t.plan(2)
+
+  const bl = new BufferList()
+  fs.createReadStream(path.join(__dirname, '/test.js'))
+    .pipe(bl)
+
+  bl.destroy()
+
+  t.equal(bl._bufs.length, 0)
+  t.equal(bl.length, 0)
+})
+
+!process.browser && tape('destroy with pipe before read end with race', function (t) {
+  t.plan(2)
+
+  const bl = new BufferList()
+
+  fs.createReadStream(path.join(__dirname, '/test.js'))
+    .pipe(bl)
+
+  setTimeout(function () {
+    bl.destroy()
+    setTimeout(function () {
+      t.equal(bl._bufs.length, 0)
+      t.equal(bl.length, 0)
+    }, 500)
+  }, 500)
+})
+
+!process.browser && tape('destroy with pipe after read end', function (t) {
+  t.plan(2)
+
+  const bl = new BufferList()
+
+  fs.createReadStream(path.join(__dirname, '/test.js'))
+    .on('end', onEnd)
+    .pipe(bl)
+
+  function onEnd () {
+    bl.destroy()
+
+    t.equal(bl._bufs.length, 0)
+    t.equal(bl.length, 0)
+  }
+})
+
+!process.browser && tape('destroy with pipe while writing to a destination', function (t) {
+  t.plan(4)
+
+  const bl = new BufferList()
+  const ds = new BufferList()
+
+  fs.createReadStream(path.join(__dirname, '/test.js'))
+    .on('end', onEnd)
+    .pipe(bl)
+
+  function onEnd () {
+    bl.pipe(ds)
+
+    setTimeout(function () {
+      bl.destroy()
+
+      t.equals(bl._bufs.length, 0)
+      t.equals(bl.length, 0)
+
+      ds.destroy()
+
+      t.equals(bl._bufs.length, 0)
+      t.equals(bl.length, 0)
+    }, 100)
+  }
+})
+
+!process.browser && tape('handle error', function (t) {
+  t.plan(2)
+
+  fs.createReadStream('/does/not/exist').pipe(BufferList(function (err, data) {
+    t.ok(err instanceof Error, 'has error')
+    t.notOk(data, 'no data')
+  }))
+})
diff --git a/server/node_modules/body-parser/HISTORY.md b/server/node_modules/body-parser/HISTORY.md
new file mode 100644
index 0000000..c9b0b5b
--- /dev/null
+++ b/server/node_modules/body-parser/HISTORY.md
@@ -0,0 +1,680 @@
+1.20.4 / 2025-12-01
+===================
+
+  * deps: qs@~6.14.0
+  * deps: use tilde notation for dependencies
+  * deps: http-errors@~2.0.1
+  * deps: raw-body@~2.5.3
+
+1.20.3 / 2024-09-10
+===================
+
+  * deps: qs@6.13.0
+  * add `depth` option to customize the depth level in the parser
+  * IMPORTANT: The default `depth` level for parsing URL-encoded data is now `32` (previously was `Infinity`)
+
+1.20.2 / 2023-02-21
+===================
+
+  * Fix strict json error message on Node.js 19+
+  * deps: content-type@~1.0.5
+    - perf: skip value escaping when unnecessary
+  * deps: raw-body@2.5.2
+
+1.20.1 / 2022-10-06
+===================
+
+  * deps: qs@6.11.0
+  * perf: remove unnecessary object clone
+
+1.20.0 / 2022-04-02
+===================
+
+  * Fix error message for json parse whitespace in `strict`
+  * Fix internal error when inflated body exceeds limit
+  * Prevent loss of async hooks context
+  * Prevent hanging when request already read
+  * deps: depd@2.0.0
+    - Replace internal `eval` usage with `Function` constructor
+    - Use instance methods on `process` to check for listeners
+  * deps: http-errors@2.0.0
+    - deps: depd@2.0.0
+    - deps: statuses@2.0.1
+  * deps: on-finished@2.4.1
+  * deps: qs@6.10.3
+  * deps: raw-body@2.5.1
+    - deps: http-errors@2.0.0
+
+1.19.2 / 2022-02-15
+===================
+
+  * deps: bytes@3.1.2
+  * deps: qs@6.9.7
+    * Fix handling of `__proto__` keys
+  * deps: raw-body@2.4.3
+    - deps: bytes@3.1.2
+
+1.19.1 / 2021-12-10
+===================
+
+  * deps: bytes@3.1.1
+  * deps: http-errors@1.8.1
+    - deps: inherits@2.0.4
+    - deps: toidentifier@1.0.1
+    - deps: setprototypeof@1.2.0
+  * deps: qs@6.9.6
+  * deps: raw-body@2.4.2
+    - deps: bytes@3.1.1
+    - deps: http-errors@1.8.1
+  * deps: safe-buffer@5.2.1
+  * deps: type-is@~1.6.18
+
+1.19.0 / 2019-04-25
+===================
+
+  * deps: bytes@3.1.0
+    - Add petabyte (`pb`) support
+  * deps: http-errors@1.7.2
+    - Set constructor name when possible
+    - deps: setprototypeof@1.1.1
+    - deps: statuses@'>= 1.5.0 < 2'
+  * deps: iconv-lite@0.4.24
+    - Added encoding MIK
+  * deps: qs@6.7.0
+    - Fix parsing array brackets after index
+  * deps: raw-body@2.4.0
+    - deps: bytes@3.1.0
+    - deps: http-errors@1.7.2
+    - deps: iconv-lite@0.4.24
+  * deps: type-is@~1.6.17
+    - deps: mime-types@~2.1.24
+    - perf: prevent internal `throw` on invalid type
+
+1.18.3 / 2018-05-14
+===================
+
+  * Fix stack trace for strict json parse error
+  * deps: depd@~1.1.2
+    - perf: remove argument reassignment
+  * deps: http-errors@~1.6.3
+    - deps: depd@~1.1.2
+    - deps: setprototypeof@1.1.0
+    - deps: statuses@'>= 1.3.1 < 2'
+  * deps: iconv-lite@0.4.23
+    - Fix loading encoding with year appended
+    - Fix deprecation warnings on Node.js 10+
+  * deps: qs@6.5.2
+  * deps: raw-body@2.3.3
+    - deps: http-errors@1.6.3
+    - deps: iconv-lite@0.4.23
+  * deps: type-is@~1.6.16
+    - deps: mime-types@~2.1.18
+
+1.18.2 / 2017-09-22
+===================
+
+  * deps: debug@2.6.9
+  * perf: remove argument reassignment
+
+1.18.1 / 2017-09-12
+===================
+
+  * deps: content-type@~1.0.4
+    - perf: remove argument reassignment
+    - perf: skip parameter parsing when no parameters
+  * deps: iconv-lite@0.4.19
+    - Fix ISO-8859-1 regression
+    - Update Windows-1255
+  * deps: qs@6.5.1
+    - Fix parsing & compacting very deep objects
+  * deps: raw-body@2.3.2
+    - deps: iconv-lite@0.4.19
+
+1.18.0 / 2017-09-08
+===================
+
+  * Fix JSON strict violation error to match native parse error
+  * Include the `body` property on verify errors
+  * Include the `type` property on all generated errors
+  * Use `http-errors` to set status code on errors
+  * deps: bytes@3.0.0
+  * deps: debug@2.6.8
+  * deps: depd@~1.1.1
+    - Remove unnecessary `Buffer` loading
+  * deps: http-errors@~1.6.2
+    - deps: depd@1.1.1
+  * deps: iconv-lite@0.4.18
+    - Add support for React Native
+    - Add a warning if not loaded as utf-8
+    - Fix CESU-8 decoding in Node.js 8
+    - Improve speed of ISO-8859-1 encoding
+  * deps: qs@6.5.0
+  * deps: raw-body@2.3.1
+    - Use `http-errors` for standard emitted errors
+    - deps: bytes@3.0.0
+    - deps: iconv-lite@0.4.18
+    - perf: skip buffer decoding on overage chunk
+  * perf: prevent internal `throw` when missing charset
+
+1.17.2 / 2017-05-17
+===================
+
+  * deps: debug@2.6.7
+    - Fix `DEBUG_MAX_ARRAY_LENGTH`
+    - deps: ms@2.0.0
+  * deps: type-is@~1.6.15
+    - deps: mime-types@~2.1.15
+
+1.17.1 / 2017-03-06
+===================
+
+  * deps: qs@6.4.0
+    - Fix regression parsing keys starting with `[`
+
+1.17.0 / 2017-03-01
+===================
+
+  * deps: http-errors@~1.6.1
+    - Make `message` property enumerable for `HttpError`s
+    - deps: setprototypeof@1.0.3
+  * deps: qs@6.3.1
+    - Fix compacting nested arrays
+
+1.16.1 / 2017-02-10
+===================
+
+  * deps: debug@2.6.1
+    - Fix deprecation messages in WebStorm and other editors
+    - Undeprecate `DEBUG_FD` set to `1` or `2`
+
+1.16.0 / 2017-01-17
+===================
+
+  * deps: debug@2.6.0
+    - Allow colors in workers
+    - Deprecated `DEBUG_FD` environment variable
+    - Fix error when running under React Native
+    - Use same color for same namespace
+    - deps: ms@0.7.2
+  * deps: http-errors@~1.5.1
+    - deps: inherits@2.0.3
+    - deps: setprototypeof@1.0.2
+    - deps: statuses@'>= 1.3.1 < 2'
+  * deps: iconv-lite@0.4.15
+    - Added encoding MS-31J
+    - Added encoding MS-932
+    - Added encoding MS-936
+    - Added encoding MS-949
+    - Added encoding MS-950
+    - Fix GBK/GB18030 handling of Euro character
+  * deps: qs@6.2.1
+    - Fix array parsing from skipping empty values
+  * deps: raw-body@~2.2.0
+    - deps: iconv-lite@0.4.15
+  * deps: type-is@~1.6.14
+    - deps: mime-types@~2.1.13
+
+1.15.2 / 2016-06-19
+===================
+
+  * deps: bytes@2.4.0
+  * deps: content-type@~1.0.2
+    - perf: enable strict mode
+  * deps: http-errors@~1.5.0
+    - Use `setprototypeof` module to replace `__proto__` setting
+    - deps: statuses@'>= 1.3.0 < 2'
+    - perf: enable strict mode
+  * deps: qs@6.2.0
+  * deps: raw-body@~2.1.7
+    - deps: bytes@2.4.0
+    - perf: remove double-cleanup on happy path
+  * deps: type-is@~1.6.13
+    - deps: mime-types@~2.1.11
+
+1.15.1 / 2016-05-05
+===================
+
+  * deps: bytes@2.3.0
+    - Drop partial bytes on all parsed units
+    - Fix parsing byte string that looks like hex
+  * deps: raw-body@~2.1.6
+    - deps: bytes@2.3.0
+  * deps: type-is@~1.6.12
+    - deps: mime-types@~2.1.10
+
+1.15.0 / 2016-02-10
+===================
+
+  * deps: http-errors@~1.4.0
+    - Add `HttpError` export, for `err instanceof createError.HttpError`
+    - deps: inherits@2.0.1
+    - deps: statuses@'>= 1.2.1 < 2'
+  * deps: qs@6.1.0
+  * deps: type-is@~1.6.11
+    - deps: mime-types@~2.1.9
+
+1.14.2 / 2015-12-16
+===================
+
+  * deps: bytes@2.2.0
+  * deps: iconv-lite@0.4.13
+  * deps: qs@5.2.0
+  * deps: raw-body@~2.1.5
+    - deps: bytes@2.2.0
+    - deps: iconv-lite@0.4.13
+  * deps: type-is@~1.6.10
+    - deps: mime-types@~2.1.8
+
+1.14.1 / 2015-09-27
+===================
+
+  * Fix issue where invalid charset results in 400 when `verify` used
+  * deps: iconv-lite@0.4.12
+    - Fix CESU-8 decoding in Node.js 4.x
+  * deps: raw-body@~2.1.4
+    - Fix masking critical errors from `iconv-lite`
+    - deps: iconv-lite@0.4.12
+  * deps: type-is@~1.6.9
+    - deps: mime-types@~2.1.7
+
+1.14.0 / 2015-09-16
+===================
+
+  * Fix JSON strict parse error to match syntax errors
+  * Provide static `require` analysis in `urlencoded` parser
+  * deps: depd@~1.1.0
+    - Support web browser loading
+  * deps: qs@5.1.0
+  * deps: raw-body@~2.1.3
+    - Fix sync callback when attaching data listener causes sync read
+  * deps: type-is@~1.6.8
+    - Fix type error when given invalid type to match against
+    - deps: mime-types@~2.1.6
+
+1.13.3 / 2015-07-31
+===================
+
+  * deps: type-is@~1.6.6
+    - deps: mime-types@~2.1.4
+
+1.13.2 / 2015-07-05
+===================
+
+  * deps: iconv-lite@0.4.11
+  * deps: qs@4.0.0
+    - Fix dropping parameters like `hasOwnProperty`
+    - Fix user-visible incompatibilities from 3.1.0
+    - Fix various parsing edge cases
+  * deps: raw-body@~2.1.2
+    - Fix error stack traces to skip `makeError`
+    - deps: iconv-lite@0.4.11
+  * deps: type-is@~1.6.4
+    - deps: mime-types@~2.1.2
+    - perf: enable strict mode
+    - perf: remove argument reassignment
+
+1.13.1 / 2015-06-16
+===================
+
+  * deps: qs@2.4.2
+    - Downgraded from 3.1.0 because of user-visible incompatibilities
+
+1.13.0 / 2015-06-14
+===================
+
+  * Add `statusCode` property on `Error`s, in addition to `status`
+  * Change `type` default to `application/json` for JSON parser
+  * Change `type` default to `application/x-www-form-urlencoded` for urlencoded parser
+  * Provide static `require` analysis
+  * Use the `http-errors` module to generate errors
+  * deps: bytes@2.1.0
+    - Slight optimizations
+  * deps: iconv-lite@0.4.10
+    - The encoding UTF-16 without BOM now defaults to UTF-16LE when detection fails
+    - Leading BOM is now removed when decoding
+  * deps: on-finished@~2.3.0
+    - Add defined behavior for HTTP `CONNECT` requests
+    - Add defined behavior for HTTP `Upgrade` requests
+    - deps: ee-first@1.1.1
+  * deps: qs@3.1.0
+    - Fix dropping parameters like `hasOwnProperty`
+    - Fix various parsing edge cases
+    - Parsed object now has `null` prototype
+  * deps: raw-body@~2.1.1
+    - Use `unpipe` module for unpiping requests
+    - deps: iconv-lite@0.4.10
+  * deps: type-is@~1.6.3
+    - deps: mime-types@~2.1.1
+    - perf: reduce try block size
+    - perf: remove bitwise operations
+  * perf: enable strict mode
+  * perf: remove argument reassignment
+  * perf: remove delete call
+
+1.12.4 / 2015-05-10
+===================
+
+  * deps: debug@~2.2.0
+  * deps: qs@2.4.2
+    - Fix allowing parameters like `constructor`
+  * deps: on-finished@~2.2.1
+  * deps: raw-body@~2.0.1
+    - Fix a false-positive when unpiping in Node.js 0.8
+    - deps: bytes@2.0.1
+  * deps: type-is@~1.6.2
+    - deps: mime-types@~2.0.11
+
+1.12.3 / 2015-04-15
+===================
+
+  * Slight efficiency improvement when not debugging
+  * deps: depd@~1.0.1
+  * deps: iconv-lite@0.4.8
+    - Add encoding alias UNICODE-1-1-UTF-7
+  * deps: raw-body@1.3.4
+    - Fix hanging callback if request aborts during read
+    - deps: iconv-lite@0.4.8
+
+1.12.2 / 2015-03-16
+===================
+
+  * deps: qs@2.4.1
+    - Fix error when parameter `hasOwnProperty` is present
+
+1.12.1 / 2015-03-15
+===================
+
+  * deps: debug@~2.1.3
+    - Fix high intensity foreground color for bold
+    - deps: ms@0.7.0
+  * deps: type-is@~1.6.1
+    - deps: mime-types@~2.0.10
+
+1.12.0 / 2015-02-13
+===================
+
+  * add `debug` messages
+  * accept a function for the `type` option
+  * use `content-type` to parse `Content-Type` headers
+  * deps: iconv-lite@0.4.7
+    - Gracefully support enumerables on `Object.prototype`
+  * deps: raw-body@1.3.3
+    - deps: iconv-lite@0.4.7
+  * deps: type-is@~1.6.0
+    - fix argument reassignment
+    - fix false-positives in `hasBody` `Transfer-Encoding` check
+    - support wildcard for both type and subtype (`*/*`)
+    - deps: mime-types@~2.0.9
+
+1.11.0 / 2015-01-30
+===================
+
+  * make internal `extended: true` depth limit infinity
+  * deps: type-is@~1.5.6
+    - deps: mime-types@~2.0.8
+
+1.10.2 / 2015-01-20
+===================
+
+  * deps: iconv-lite@0.4.6
+    - Fix rare aliases of single-byte encodings
+  * deps: raw-body@1.3.2
+    - deps: iconv-lite@0.4.6
+
+1.10.1 / 2015-01-01
+===================
+
+  * deps: on-finished@~2.2.0
+  * deps: type-is@~1.5.5
+    - deps: mime-types@~2.0.7
+
+1.10.0 / 2014-12-02
+===================
+
+  * make internal `extended: true` array limit dynamic
+
+1.9.3 / 2014-11-21
+==================
+
+  * deps: iconv-lite@0.4.5
+    - Fix Windows-31J and X-SJIS encoding support
+  * deps: qs@2.3.3
+    - Fix `arrayLimit` behavior
+  * deps: raw-body@1.3.1
+    - deps: iconv-lite@0.4.5
+  * deps: type-is@~1.5.3
+    - deps: mime-types@~2.0.3
+
+1.9.2 / 2014-10-27
+==================
+
+  * deps: qs@2.3.2
+    - Fix parsing of mixed objects and values
+
+1.9.1 / 2014-10-22
+==================
+
+  * deps: on-finished@~2.1.1
+    - Fix handling of pipelined requests
+  * deps: qs@2.3.0
+    - Fix parsing of mixed implicit and explicit arrays
+  * deps: type-is@~1.5.2
+    - deps: mime-types@~2.0.2
+
+1.9.0 / 2014-09-24
+==================
+
+  * include the charset in "unsupported charset" error message
+  * include the encoding in "unsupported content encoding" error message
+  * deps: depd@~1.0.0
+
+1.8.4 / 2014-09-23
+==================
+
+  * fix content encoding to be case-insensitive
+
+1.8.3 / 2014-09-19
+==================
+
+  * deps: qs@2.2.4
+    - Fix issue with object keys starting with numbers truncated
+
+1.8.2 / 2014-09-15
+==================
+
+  * deps: depd@0.4.5
+
+1.8.1 / 2014-09-07
+==================
+
+  * deps: media-typer@0.3.0
+  * deps: type-is@~1.5.1
+
+1.8.0 / 2014-09-05
+==================
+
+  * make empty-body-handling consistent between chunked requests
+    - empty `json` produces `{}`
+    - empty `raw` produces `new Buffer(0)`
+    - empty `text` produces `''`
+    - empty `urlencoded` produces `{}`
+  * deps: qs@2.2.3
+    - Fix issue where first empty value in array is discarded
+  * deps: type-is@~1.5.0
+    - fix `hasbody` to be true for `content-length: 0`
+
+1.7.0 / 2014-09-01
+==================
+
+  * add `parameterLimit` option to `urlencoded` parser
+  * change `urlencoded` extended array limit to 100
+  * respond with 413 when over `parameterLimit` in `urlencoded`
+
+1.6.7 / 2014-08-29
+==================
+
+  * deps: qs@2.2.2
+    - Remove unnecessary cloning
+
+1.6.6 / 2014-08-27
+==================
+
+  * deps: qs@2.2.0
+    - Array parsing fix
+    - Performance improvements
+
+1.6.5 / 2014-08-16
+==================
+
+  * deps: on-finished@2.1.0
+
+1.6.4 / 2014-08-14
+==================
+
+  * deps: qs@1.2.2
+
+1.6.3 / 2014-08-10
+==================
+
+  * deps: qs@1.2.1
+
+1.6.2 / 2014-08-07
+==================
+
+  * deps: qs@1.2.0
+    - Fix parsing array of objects
+
+1.6.1 / 2014-08-06
+==================
+
+  * deps: qs@1.1.0
+    - Accept urlencoded square brackets
+    - Accept empty values in implicit array notation
+
+1.6.0 / 2014-08-05
+==================
+
+  * deps: qs@1.0.2
+    - Complete rewrite
+    - Limits array length to 20
+    - Limits object depth to 5
+    - Limits parameters to 1,000
+
+1.5.2 / 2014-07-27
+==================
+
+  * deps: depd@0.4.4
+    - Work-around v8 generating empty stack traces
+
+1.5.1 / 2014-07-26
+==================
+
+  * deps: depd@0.4.3
+    - Fix exception when global `Error.stackTraceLimit` is too low
+
+1.5.0 / 2014-07-20
+==================
+
+  * deps: depd@0.4.2
+    - Add `TRACE_DEPRECATION` environment variable
+    - Remove non-standard grey color from color output
+    - Support `--no-deprecation` argument
+    - Support `--trace-deprecation` argument
+  * deps: iconv-lite@0.4.4
+    - Added encoding UTF-7
+  * deps: raw-body@1.3.0
+    - deps: iconv-lite@0.4.4
+    - Added encoding UTF-7
+    - Fix `Cannot switch to old mode now` error on Node.js 0.10+
+  * deps: type-is@~1.3.2
+
+1.4.3 / 2014-06-19
+==================
+
+  * deps: type-is@1.3.1
+    - fix global variable leak
+
+1.4.2 / 2014-06-19
+==================
+
+  * deps: type-is@1.3.0
+    - improve type parsing
+
+1.4.1 / 2014-06-19
+==================
+
+  * fix urlencoded extended deprecation message
+
+1.4.0 / 2014-06-19
+==================
+
+  * add `text` parser
+  * add `raw` parser
+  * check accepted charset in content-type (accepts utf-8)
+  * check accepted encoding in content-encoding (accepts identity)
+  * deprecate `bodyParser()` middleware; use `.json()` and `.urlencoded()` as needed
+  * deprecate `urlencoded()` without provided `extended` option
+  * lazy-load urlencoded parsers
+  * parsers split into files for reduced mem usage
+  * support gzip and deflate bodies
+    - set `inflate: false` to turn off
+  * deps: raw-body@1.2.2
+    - Support all encodings from `iconv-lite`
+
+1.3.1 / 2014-06-11
+==================
+
+  * deps: type-is@1.2.1
+    - Switch dependency from mime to mime-types@1.0.0
+
+1.3.0 / 2014-05-31
+==================
+
+  * add `extended` option to urlencoded parser
+
+1.2.2 / 2014-05-27
+==================
+
+  * deps: raw-body@1.1.6
+    - assert stream encoding on node.js 0.8
+    - assert stream encoding on node.js < 0.10.6
+    - deps: bytes@1
+
+1.2.1 / 2014-05-26
+==================
+
+  * invoke `next(err)` after request fully read
+    - prevents hung responses and socket hang ups
+
+1.2.0 / 2014-05-11
+==================
+
+  * add `verify` option
+  * deps: type-is@1.2.0
+    - support suffix matching
+
+1.1.2 / 2014-05-11
+==================
+
+  * improve json parser speed
+
+1.1.1 / 2014-05-11
+==================
+
+  * fix repeated limit parsing with every request
+
+1.1.0 / 2014-05-10
+==================
+
+  * add `type` option
+  * deps: pin for safety and consistency
+
+1.0.2 / 2014-04-14
+==================
+
+  * use `type-is` module
+
+1.0.1 / 2014-03-20
+==================
+
+  * lower default limits to 100kb
diff --git a/server/node_modules/body-parser/LICENSE b/server/node_modules/body-parser/LICENSE
new file mode 100644
index 0000000..386b7b6
--- /dev/null
+++ b/server/node_modules/body-parser/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2014 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2014-2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/body-parser/README.md b/server/node_modules/body-parser/README.md
new file mode 100644
index 0000000..f6661b7
--- /dev/null
+++ b/server/node_modules/body-parser/README.md
@@ -0,0 +1,476 @@
+# body-parser
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Build Status][ci-image]][ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+[![OpenSSF Scorecard Badge][ossf-scorecard-badge]][ossf-scorecard-visualizer]
+
+Node.js body parsing middleware.
+
+Parse incoming request bodies in a middleware before your handlers, available
+under the `req.body` property.
+
+**Note** As `req.body`'s shape is based on user-controlled input, all
+properties and values in this object are untrusted and should be validated
+before trusting. For example, `req.body.foo.toString()` may fail in multiple
+ways, for example the `foo` property may not be there or may not be a string,
+and `toString` may not be a function and instead a string or other user input.
+
+[Learn about the anatomy of an HTTP transaction in Node.js](https://nodejs.org/en/docs/guides/anatomy-of-an-http-transaction/).
+
+_This does not handle multipart bodies_, due to their complex and typically
+large nature. For multipart bodies, you may be interested in the following
+modules:
+
+  * [busboy](https://www.npmjs.org/package/busboy#readme) and
+    [connect-busboy](https://www.npmjs.org/package/connect-busboy#readme)
+  * [multiparty](https://www.npmjs.org/package/multiparty#readme) and
+    [connect-multiparty](https://www.npmjs.org/package/connect-multiparty#readme)
+  * [formidable](https://www.npmjs.org/package/formidable#readme)
+  * [multer](https://www.npmjs.org/package/multer#readme)
+
+This module provides the following parsers:
+
+  * [JSON body parser](#bodyparserjsonoptions)
+  * [Raw body parser](#bodyparserrawoptions)
+  * [Text body parser](#bodyparsertextoptions)
+  * [URL-encoded form body parser](#bodyparserurlencodedoptions)
+
+Other body parsers you might be interested in:
+
+- [body](https://www.npmjs.org/package/body#readme)
+- [co-body](https://www.npmjs.org/package/co-body#readme)
+
+## Installation
+
+```sh
+$ npm install body-parser
+```
+
+## API
+
+```js
+var bodyParser = require('body-parser')
+```
+
+The `bodyParser` object exposes various factories to create middlewares. All
+middlewares will populate the `req.body` property with the parsed body when
+the `Content-Type` request header matches the `type` option, or an empty
+object (`{}`) if there was no body to parse, the `Content-Type` was not matched,
+or an error occurred.
+
+The various errors returned by this module are described in the
+[errors section](#errors).
+
+### bodyParser.json([options])
+
+Returns middleware that only parses `json` and only looks at requests where
+the `Content-Type` header matches the `type` option. This parser accepts any
+Unicode encoding of the body and supports automatic inflation of `gzip` and
+`deflate` encodings.
+
+A new `body` object containing the parsed data is populated on the `request`
+object after the middleware (i.e. `req.body`).
+
+#### Options
+
+The `json` function takes an optional `options` object that may contain any of
+the following keys:
+
+##### inflate
+
+When set to `true`, then deflated (compressed) bodies will be inflated; when
+`false`, deflated bodies are rejected. Defaults to `true`.
+
+##### limit
+
+Controls the maximum request body size. If this is a number, then the value
+specifies the number of bytes; if it is a string, the value is passed to the
+[bytes](https://www.npmjs.com/package/bytes) library for parsing. Defaults
+to `'100kb'`.
+
+##### reviver
+
+The `reviver` option is passed directly to `JSON.parse` as the second
+argument. You can find more information on this argument
+[in the MDN documentation about JSON.parse](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse#Example.3A_Using_the_reviver_parameter).
+
+##### strict
+
+When set to `true`, will only accept arrays and objects; when `false` will
+accept anything `JSON.parse` accepts. Defaults to `true`.
+
+##### type
+
+The `type` option is used to determine what media type the middleware will
+parse. This option can be a string, array of strings, or a function. If not a
+function, `type` option is passed directly to the
+[type-is](https://www.npmjs.org/package/type-is#readme) library and this can
+be an extension name (like `json`), a mime type (like `application/json`), or
+a mime type with a wildcard (like `*/*` or `*/json`). If a function, the `type`
+option is called as `fn(req)` and the request is parsed if it returns a truthy
+value. Defaults to `application/json`.
+
+##### verify
+
+The `verify` option, if supplied, is called as `verify(req, res, buf, encoding)`,
+where `buf` is a `Buffer` of the raw request body and `encoding` is the
+encoding of the request. The parsing can be aborted by throwing an error.
+
+### bodyParser.raw([options])
+
+Returns middleware that parses all bodies as a `Buffer` and only looks at
+requests where the `Content-Type` header matches the `type` option. This
+parser supports automatic inflation of `gzip` and `deflate` encodings.
+
+A new `body` object containing the parsed data is populated on the `request`
+object after the middleware (i.e. `req.body`). This will be a `Buffer` object
+of the body.
+
+#### Options
+
+The `raw` function takes an optional `options` object that may contain any of
+the following keys:
+
+##### inflate
+
+When set to `true`, then deflated (compressed) bodies will be inflated; when
+`false`, deflated bodies are rejected. Defaults to `true`.
+
+##### limit
+
+Controls the maximum request body size. If this is a number, then the value
+specifies the number of bytes; if it is a string, the value is passed to the
+[bytes](https://www.npmjs.com/package/bytes) library for parsing. Defaults
+to `'100kb'`.
+
+##### type
+
+The `type` option is used to determine what media type the middleware will
+parse. This option can be a string, array of strings, or a function.
+If not a function, `type` option is passed directly to the
+[type-is](https://www.npmjs.org/package/type-is#readme) library and this
+can be an extension name (like `bin`), a mime type (like
+`application/octet-stream`), or a mime type with a wildcard (like `*/*` or
+`application/*`). If a function, the `type` option is called as `fn(req)`
+and the request is parsed if it returns a truthy value. Defaults to
+`application/octet-stream`.
+
+##### verify
+
+The `verify` option, if supplied, is called as `verify(req, res, buf, encoding)`,
+where `buf` is a `Buffer` of the raw request body and `encoding` is the
+encoding of the request. The parsing can be aborted by throwing an error.
+
+### bodyParser.text([options])
+
+Returns middleware that parses all bodies as a string and only looks at
+requests where the `Content-Type` header matches the `type` option. This
+parser supports automatic inflation of `gzip` and `deflate` encodings.
+
+A new `body` string containing the parsed data is populated on the `request`
+object after the middleware (i.e. `req.body`). This will be a string of the
+body.
+
+#### Options
+
+The `text` function takes an optional `options` object that may contain any of
+the following keys:
+
+##### defaultCharset
+
+Specify the default character set for the text content if the charset is not
+specified in the `Content-Type` header of the request. Defaults to `utf-8`.
+
+##### inflate
+
+When set to `true`, then deflated (compressed) bodies will be inflated; when
+`false`, deflated bodies are rejected. Defaults to `true`.
+
+##### limit
+
+Controls the maximum request body size. If this is a number, then the value
+specifies the number of bytes; if it is a string, the value is passed to the
+[bytes](https://www.npmjs.com/package/bytes) library for parsing. Defaults
+to `'100kb'`.
+
+##### type
+
+The `type` option is used to determine what media type the middleware will
+parse. This option can be a string, array of strings, or a function. If not
+a function, `type` option is passed directly to the
+[type-is](https://www.npmjs.org/package/type-is#readme) library and this can
+be an extension name (like `txt`), a mime type (like `text/plain`), or a mime
+type with a wildcard (like `*/*` or `text/*`). If a function, the `type`
+option is called as `fn(req)` and the request is parsed if it returns a
+truthy value. Defaults to `text/plain`.
+
+##### verify
+
+The `verify` option, if supplied, is called as `verify(req, res, buf, encoding)`,
+where `buf` is a `Buffer` of the raw request body and `encoding` is the
+encoding of the request. The parsing can be aborted by throwing an error.
+
+### bodyParser.urlencoded([options])
+
+Returns middleware that only parses `urlencoded` bodies and only looks at
+requests where the `Content-Type` header matches the `type` option. This
+parser accepts only UTF-8 encoding of the body and supports automatic
+inflation of `gzip` and `deflate` encodings.
+
+A new `body` object containing the parsed data is populated on the `request`
+object after the middleware (i.e. `req.body`). This object will contain
+key-value pairs, where the value can be a string or array (when `extended` is
+`false`), or any type (when `extended` is `true`).
+
+#### Options
+
+The `urlencoded` function takes an optional `options` object that may contain
+any of the following keys:
+
+##### extended
+
+The `extended` option allows to choose between parsing the URL-encoded data
+with the `querystring` library (when `false`) or the `qs` library (when
+`true`). The "extended" syntax allows for rich objects and arrays to be
+encoded into the URL-encoded format, allowing for a JSON-like experience
+with URL-encoded. For more information, please
+[see the qs library](https://www.npmjs.org/package/qs#readme).
+
+Defaults to `true`, but using the default has been deprecated. Please
+research into the difference between `qs` and `querystring` and choose the
+appropriate setting.
+
+##### inflate
+
+When set to `true`, then deflated (compressed) bodies will be inflated; when
+`false`, deflated bodies are rejected. Defaults to `true`.
+
+##### limit
+
+Controls the maximum request body size. If this is a number, then the value
+specifies the number of bytes; if it is a string, the value is passed to the
+[bytes](https://www.npmjs.com/package/bytes) library for parsing. Defaults
+to `'100kb'`.
+
+##### parameterLimit
+
+The `parameterLimit` option controls the maximum number of parameters that
+are allowed in the URL-encoded data. If a request contains more parameters
+than this value, a 413 will be returned to the client. Defaults to `1000`.
+
+##### type
+
+The `type` option is used to determine what media type the middleware will
+parse. This option can be a string, array of strings, or a function. If not
+a function, `type` option is passed directly to the
+[type-is](https://www.npmjs.org/package/type-is#readme) library and this can
+be an extension name (like `urlencoded`), a mime type (like
+`application/x-www-form-urlencoded`), or a mime type with a wildcard (like
+`*/x-www-form-urlencoded`). If a function, the `type` option is called as
+`fn(req)` and the request is parsed if it returns a truthy value. Defaults
+to `application/x-www-form-urlencoded`.
+
+##### verify
+
+The `verify` option, if supplied, is called as `verify(req, res, buf, encoding)`,
+where `buf` is a `Buffer` of the raw request body and `encoding` is the
+encoding of the request. The parsing can be aborted by throwing an error.
+
+#### depth
+
+The `depth` option is used to configure the maximum depth of the `qs` library when `extended` is `true`. This allows you to limit the amount of keys that are parsed and can be useful to prevent certain types of abuse. Defaults to `32`. It is recommended to keep this value as low as possible.
+
+## Errors
+
+The middlewares provided by this module create errors using the
+[`http-errors` module](https://www.npmjs.com/package/http-errors). The errors
+will typically have a `status`/`statusCode` property that contains the suggested
+HTTP response code, an `expose` property to determine if the `message` property
+should be displayed to the client, a `type` property to determine the type of
+error without matching against the `message`, and a `body` property containing
+the read body, if available.
+
+The following are the common errors created, though any error can come through
+for various reasons.
+
+### content encoding unsupported
+
+This error will occur when the request had a `Content-Encoding` header that
+contained an encoding but the "inflation" option was set to `false`. The
+`status` property is set to `415`, the `type` property is set to
+`'encoding.unsupported'`, and the `charset` property will be set to the
+encoding that is unsupported.
+
+### entity parse failed
+
+This error will occur when the request contained an entity that could not be
+parsed by the middleware. The `status` property is set to `400`, the `type`
+property is set to `'entity.parse.failed'`, and the `body` property is set to
+the entity value that failed parsing.
+
+### entity verify failed
+
+This error will occur when the request contained an entity that could not be
+failed verification by the defined `verify` option. The `status` property is
+set to `403`, the `type` property is set to `'entity.verify.failed'`, and the
+`body` property is set to the entity value that failed verification.
+
+### request aborted
+
+This error will occur when the request is aborted by the client before reading
+the body has finished. The `received` property will be set to the number of
+bytes received before the request was aborted and the `expected` property is
+set to the number of expected bytes. The `status` property is set to `400`
+and `type` property is set to `'request.aborted'`.
+
+### request entity too large
+
+This error will occur when the request body's size is larger than the "limit"
+option. The `limit` property will be set to the byte limit and the `length`
+property will be set to the request body's length. The `status` property is
+set to `413` and the `type` property is set to `'entity.too.large'`.
+
+### request size did not match content length
+
+This error will occur when the request's length did not match the length from
+the `Content-Length` header. This typically occurs when the request is malformed,
+typically when the `Content-Length` header was calculated based on characters
+instead of bytes. The `status` property is set to `400` and the `type` property
+is set to `'request.size.invalid'`.
+
+### stream encoding should not be set
+
+This error will occur when something called the `req.setEncoding` method prior
+to this middleware. This module operates directly on bytes only and you cannot
+call `req.setEncoding` when using this module. The `status` property is set to
+`500` and the `type` property is set to `'stream.encoding.set'`.
+
+### stream is not readable
+
+This error will occur when the request is no longer readable when this middleware
+attempts to read it. This typically means something other than a middleware from
+this module read the request body already and the middleware was also configured to
+read the same request. The `status` property is set to `500` and the `type`
+property is set to `'stream.not.readable'`.
+
+### too many parameters
+
+This error will occur when the content of the request exceeds the configured
+`parameterLimit` for the `urlencoded` parser. The `status` property is set to
+`413` and the `type` property is set to `'parameters.too.many'`.
+
+### unsupported charset "BOGUS"
+
+This error will occur when the request had a charset parameter in the
+`Content-Type` header, but the `iconv-lite` module does not support it OR the
+parser does not support it. The charset is contained in the message as well
+as in the `charset` property. The `status` property is set to `415`, the
+`type` property is set to `'charset.unsupported'`, and the `charset` property
+is set to the charset that is unsupported.
+
+### unsupported content encoding "bogus"
+
+This error will occur when the request had a `Content-Encoding` header that
+contained an unsupported encoding. The encoding is contained in the message
+as well as in the `encoding` property. The `status` property is set to `415`,
+the `type` property is set to `'encoding.unsupported'`, and the `encoding`
+property is set to the encoding that is unsupported.
+
+### The input exceeded the depth
+
+This error occurs when using `bodyParser.urlencoded` with the `extended` property set to `true` and the input exceeds the configured `depth` option. The `status` property is set to `400`. It is recommended to review the `depth` option and evaluate if it requires a higher value. When the `depth` option is set to `32` (default value), the error will not be thrown.
+
+## Examples
+
+### Express/Connect top-level generic
+
+This example demonstrates adding a generic JSON and URL-encoded parser as a
+top-level middleware, which will parse the bodies of all incoming requests.
+This is the simplest setup.
+
+```js
+var express = require('express')
+var bodyParser = require('body-parser')
+
+var app = express()
+
+// parse application/x-www-form-urlencoded
+app.use(bodyParser.urlencoded({ extended: false }))
+
+// parse application/json
+app.use(bodyParser.json())
+
+app.use(function (req, res) {
+  res.setHeader('Content-Type', 'text/plain')
+  res.write('you posted:\n')
+  res.end(JSON.stringify(req.body, null, 2))
+})
+```
+
+### Express route-specific
+
+This example demonstrates adding body parsers specifically to the routes that
+need them. In general, this is the most recommended way to use body-parser with
+Express.
+
+```js
+var express = require('express')
+var bodyParser = require('body-parser')
+
+var app = express()
+
+// create application/json parser
+var jsonParser = bodyParser.json()
+
+// create application/x-www-form-urlencoded parser
+var urlencodedParser = bodyParser.urlencoded({ extended: false })
+
+// POST /login gets urlencoded bodies
+app.post('/login', urlencodedParser, function (req, res) {
+  res.send('welcome, ' + req.body.username)
+})
+
+// POST /api/users gets JSON bodies
+app.post('/api/users', jsonParser, function (req, res) {
+  // create user in req.body
+})
+```
+
+### Change accepted type for parsers
+
+All the parsers accept a `type` option which allows you to change the
+`Content-Type` that the middleware will parse.
+
+```js
+var express = require('express')
+var bodyParser = require('body-parser')
+
+var app = express()
+
+// parse various different custom JSON types as JSON
+app.use(bodyParser.json({ type: 'application/*+json' }))
+
+// parse some custom thing into a Buffer
+app.use(bodyParser.raw({ type: 'application/vnd.custom-type' }))
+
+// parse an HTML body into a string
+app.use(bodyParser.text({ type: 'text/html' }))
+```
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/expressjs/body-parser/master?label=ci
+[ci-url]: https://github.com/expressjs/body-parser/actions/workflows/ci.yml
+[coveralls-image]: https://badgen.net/coveralls/c/github/expressjs/body-parser/master
+[coveralls-url]: https://coveralls.io/r/expressjs/body-parser?branch=master
+[node-version-image]: https://badgen.net/npm/node/body-parser
+[node-version-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/body-parser
+[npm-url]: https://npmjs.org/package/body-parser
+[npm-version-image]: https://badgen.net/npm/v/body-parser
+[ossf-scorecard-badge]: https://api.scorecard.dev/projects/github.com/expressjs/body-parser/badge
+[ossf-scorecard-visualizer]: https://ossf.github.io/scorecard-visualizer/#/projects/github.com/expressjs/body-parser
\ No newline at end of file
diff --git a/server/node_modules/body-parser/index.js b/server/node_modules/body-parser/index.js
new file mode 100644
index 0000000..bb24d73
--- /dev/null
+++ b/server/node_modules/body-parser/index.js
@@ -0,0 +1,156 @@
+/*!
+ * body-parser
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var deprecate = require('depd')('body-parser')
+
+/**
+ * Cache of loaded parsers.
+ * @private
+ */
+
+var parsers = Object.create(null)
+
+/**
+ * @typedef Parsers
+ * @type {function}
+ * @property {function} json
+ * @property {function} raw
+ * @property {function} text
+ * @property {function} urlencoded
+ */
+
+/**
+ * Module exports.
+ * @type {Parsers}
+ */
+
+exports = module.exports = deprecate.function(bodyParser,
+  'bodyParser: use individual json/urlencoded middlewares')
+
+/**
+ * JSON parser.
+ * @public
+ */
+
+Object.defineProperty(exports, 'json', {
+  configurable: true,
+  enumerable: true,
+  get: createParserGetter('json')
+})
+
+/**
+ * Raw parser.
+ * @public
+ */
+
+Object.defineProperty(exports, 'raw', {
+  configurable: true,
+  enumerable: true,
+  get: createParserGetter('raw')
+})
+
+/**
+ * Text parser.
+ * @public
+ */
+
+Object.defineProperty(exports, 'text', {
+  configurable: true,
+  enumerable: true,
+  get: createParserGetter('text')
+})
+
+/**
+ * URL-encoded parser.
+ * @public
+ */
+
+Object.defineProperty(exports, 'urlencoded', {
+  configurable: true,
+  enumerable: true,
+  get: createParserGetter('urlencoded')
+})
+
+/**
+ * Create a middleware to parse json and urlencoded bodies.
+ *
+ * @param {object} [options]
+ * @return {function}
+ * @deprecated
+ * @public
+ */
+
+function bodyParser (options) {
+  // use default type for parsers
+  var opts = Object.create(options || null, {
+    type: {
+      configurable: true,
+      enumerable: true,
+      value: undefined,
+      writable: true
+    }
+  })
+
+  var _urlencoded = exports.urlencoded(opts)
+  var _json = exports.json(opts)
+
+  return function bodyParser (req, res, next) {
+    _json(req, res, function (err) {
+      if (err) return next(err)
+      _urlencoded(req, res, next)
+    })
+  }
+}
+
+/**
+ * Create a getter for loading a parser.
+ * @private
+ */
+
+function createParserGetter (name) {
+  return function get () {
+    return loadParser(name)
+  }
+}
+
+/**
+ * Load a parser module.
+ * @private
+ */
+
+function loadParser (parserName) {
+  var parser = parsers[parserName]
+
+  if (parser !== undefined) {
+    return parser
+  }
+
+  // this uses a switch for static require analysis
+  switch (parserName) {
+    case 'json':
+      parser = require('./lib/types/json')
+      break
+    case 'raw':
+      parser = require('./lib/types/raw')
+      break
+    case 'text':
+      parser = require('./lib/types/text')
+      break
+    case 'urlencoded':
+      parser = require('./lib/types/urlencoded')
+      break
+  }
+
+  // store to prevent invoking require()
+  return (parsers[parserName] = parser)
+}
diff --git a/server/node_modules/body-parser/lib/read.js b/server/node_modules/body-parser/lib/read.js
new file mode 100644
index 0000000..fce6283
--- /dev/null
+++ b/server/node_modules/body-parser/lib/read.js
@@ -0,0 +1,205 @@
+/*!
+ * body-parser
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var createError = require('http-errors')
+var destroy = require('destroy')
+var getBody = require('raw-body')
+var iconv = require('iconv-lite')
+var onFinished = require('on-finished')
+var unpipe = require('unpipe')
+var zlib = require('zlib')
+
+/**
+ * Module exports.
+ */
+
+module.exports = read
+
+/**
+ * Read a request into a buffer and parse.
+ *
+ * @param {object} req
+ * @param {object} res
+ * @param {function} next
+ * @param {function} parse
+ * @param {function} debug
+ * @param {object} options
+ * @private
+ */
+
+function read (req, res, next, parse, debug, options) {
+  var length
+  var opts = options
+  var stream
+
+  // flag as parsed
+  req._body = true
+
+  // read options
+  var encoding = opts.encoding !== null
+    ? opts.encoding
+    : null
+  var verify = opts.verify
+
+  try {
+    // get the content stream
+    stream = contentstream(req, debug, opts.inflate)
+    length = stream.length
+    stream.length = undefined
+  } catch (err) {
+    return next(err)
+  }
+
+  // set raw-body options
+  opts.length = length
+  opts.encoding = verify
+    ? null
+    : encoding
+
+  // assert charset is supported
+  if (opts.encoding === null && encoding !== null && !iconv.encodingExists(encoding)) {
+    return next(createError(415, 'unsupported charset "' + encoding.toUpperCase() + '"', {
+      charset: encoding.toLowerCase(),
+      type: 'charset.unsupported'
+    }))
+  }
+
+  // read body
+  debug('read body')
+  getBody(stream, opts, function (error, body) {
+    if (error) {
+      var _error
+
+      if (error.type === 'encoding.unsupported') {
+        // echo back charset
+        _error = createError(415, 'unsupported charset "' + encoding.toUpperCase() + '"', {
+          charset: encoding.toLowerCase(),
+          type: 'charset.unsupported'
+        })
+      } else {
+        // set status code on error
+        _error = createError(400, error)
+      }
+
+      // unpipe from stream and destroy
+      if (stream !== req) {
+        unpipe(req)
+        destroy(stream, true)
+      }
+
+      // read off entire request
+      dump(req, function onfinished () {
+        next(createError(400, _error))
+      })
+      return
+    }
+
+    // verify
+    if (verify) {
+      try {
+        debug('verify body')
+        verify(req, res, body, encoding)
+      } catch (err) {
+        next(createError(403, err, {
+          body: body,
+          type: err.type || 'entity.verify.failed'
+        }))
+        return
+      }
+    }
+
+    // parse
+    var str = body
+    try {
+      debug('parse body')
+      str = typeof body !== 'string' && encoding !== null
+        ? iconv.decode(body, encoding)
+        : body
+      req.body = parse(str)
+    } catch (err) {
+      next(createError(400, err, {
+        body: str,
+        type: err.type || 'entity.parse.failed'
+      }))
+      return
+    }
+
+    next()
+  })
+}
+
+/**
+ * Get the content stream of the request.
+ *
+ * @param {object} req
+ * @param {function} debug
+ * @param {boolean} [inflate=true]
+ * @return {object}
+ * @api private
+ */
+
+function contentstream (req, debug, inflate) {
+  var encoding = (req.headers['content-encoding'] || 'identity').toLowerCase()
+  var length = req.headers['content-length']
+  var stream
+
+  debug('content-encoding "%s"', encoding)
+
+  if (inflate === false && encoding !== 'identity') {
+    throw createError(415, 'content encoding unsupported', {
+      encoding: encoding,
+      type: 'encoding.unsupported'
+    })
+  }
+
+  switch (encoding) {
+    case 'deflate':
+      stream = zlib.createInflate()
+      debug('inflate body')
+      req.pipe(stream)
+      break
+    case 'gzip':
+      stream = zlib.createGunzip()
+      debug('gunzip body')
+      req.pipe(stream)
+      break
+    case 'identity':
+      stream = req
+      stream.length = length
+      break
+    default:
+      throw createError(415, 'unsupported content encoding "' + encoding + '"', {
+        encoding: encoding,
+        type: 'encoding.unsupported'
+      })
+  }
+
+  return stream
+}
+
+/**
+ * Dump the contents of a request.
+ *
+ * @param {object} req
+ * @param {function} callback
+ * @api private
+ */
+
+function dump (req, callback) {
+  if (onFinished.isFinished(req)) {
+    callback(null)
+  } else {
+    onFinished(req, callback)
+    req.resume()
+  }
+}
diff --git a/server/node_modules/body-parser/lib/types/json.js b/server/node_modules/body-parser/lib/types/json.js
new file mode 100644
index 0000000..59f3f7e
--- /dev/null
+++ b/server/node_modules/body-parser/lib/types/json.js
@@ -0,0 +1,247 @@
+/*!
+ * body-parser
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var bytes = require('bytes')
+var contentType = require('content-type')
+var createError = require('http-errors')
+var debug = require('debug')('body-parser:json')
+var read = require('../read')
+var typeis = require('type-is')
+
+/**
+ * Module exports.
+ */
+
+module.exports = json
+
+/**
+ * RegExp to match the first non-space in a string.
+ *
+ * Allowed whitespace is defined in RFC 7159:
+ *
+ *    ws = *(
+ *            %x20 /              ; Space
+ *            %x09 /              ; Horizontal tab
+ *            %x0A /              ; Line feed or New line
+ *            %x0D )              ; Carriage return
+ */
+
+var FIRST_CHAR_REGEXP = /^[\x20\x09\x0a\x0d]*([^\x20\x09\x0a\x0d])/ // eslint-disable-line no-control-regex
+
+var JSON_SYNTAX_CHAR = '#'
+var JSON_SYNTAX_REGEXP = /#+/g
+
+/**
+ * Create a middleware to parse JSON bodies.
+ *
+ * @param {object} [options]
+ * @return {function}
+ * @public
+ */
+
+function json (options) {
+  var opts = options || {}
+
+  var limit = typeof opts.limit !== 'number'
+    ? bytes.parse(opts.limit || '100kb')
+    : opts.limit
+  var inflate = opts.inflate !== false
+  var reviver = opts.reviver
+  var strict = opts.strict !== false
+  var type = opts.type || 'application/json'
+  var verify = opts.verify || false
+
+  if (verify !== false && typeof verify !== 'function') {
+    throw new TypeError('option verify must be function')
+  }
+
+  // create the appropriate type checking function
+  var shouldParse = typeof type !== 'function'
+    ? typeChecker(type)
+    : type
+
+  function parse (body) {
+    if (body.length === 0) {
+      // special-case empty json body, as it's a common client-side mistake
+      // TODO: maybe make this configurable or part of "strict" option
+      return {}
+    }
+
+    if (strict) {
+      var first = firstchar(body)
+
+      if (first !== '{' && first !== '[') {
+        debug('strict violation')
+        throw createStrictSyntaxError(body, first)
+      }
+    }
+
+    try {
+      debug('parse json')
+      return JSON.parse(body, reviver)
+    } catch (e) {
+      throw normalizeJsonSyntaxError(e, {
+        message: e.message,
+        stack: e.stack
+      })
+    }
+  }
+
+  return function jsonParser (req, res, next) {
+    if (req._body) {
+      debug('body already parsed')
+      next()
+      return
+    }
+
+    req.body = req.body || {}
+
+    // skip requests without bodies
+    if (!typeis.hasBody(req)) {
+      debug('skip empty body')
+      next()
+      return
+    }
+
+    debug('content-type %j', req.headers['content-type'])
+
+    // determine if request should be parsed
+    if (!shouldParse(req)) {
+      debug('skip parsing')
+      next()
+      return
+    }
+
+    // assert charset per RFC 7159 sec 8.1
+    var charset = getCharset(req) || 'utf-8'
+    if (charset.slice(0, 4) !== 'utf-') {
+      debug('invalid charset')
+      next(createError(415, 'unsupported charset "' + charset.toUpperCase() + '"', {
+        charset: charset,
+        type: 'charset.unsupported'
+      }))
+      return
+    }
+
+    // read
+    read(req, res, next, parse, debug, {
+      encoding: charset,
+      inflate: inflate,
+      limit: limit,
+      verify: verify
+    })
+  }
+}
+
+/**
+ * Create strict violation syntax error matching native error.
+ *
+ * @param {string} str
+ * @param {string} char
+ * @return {Error}
+ * @private
+ */
+
+function createStrictSyntaxError (str, char) {
+  var index = str.indexOf(char)
+  var partial = ''
+
+  if (index !== -1) {
+    partial = str.substring(0, index) + JSON_SYNTAX_CHAR
+
+    for (var i = index + 1; i < str.length; i++) {
+      partial += JSON_SYNTAX_CHAR
+    }
+  }
+
+  try {
+    JSON.parse(partial); /* istanbul ignore next */ throw new SyntaxError('strict violation')
+  } catch (e) {
+    return normalizeJsonSyntaxError(e, {
+      message: e.message.replace(JSON_SYNTAX_REGEXP, function (placeholder) {
+        return str.substring(index, index + placeholder.length)
+      }),
+      stack: e.stack
+    })
+  }
+}
+
+/**
+ * Get the first non-whitespace character in a string.
+ *
+ * @param {string} str
+ * @return {function}
+ * @private
+ */
+
+function firstchar (str) {
+  var match = FIRST_CHAR_REGEXP.exec(str)
+
+  return match
+    ? match[1]
+    : undefined
+}
+
+/**
+ * Get the charset of a request.
+ *
+ * @param {object} req
+ * @api private
+ */
+
+function getCharset (req) {
+  try {
+    return (contentType.parse(req).parameters.charset || '').toLowerCase()
+  } catch (e) {
+    return undefined
+  }
+}
+
+/**
+ * Normalize a SyntaxError for JSON.parse.
+ *
+ * @param {SyntaxError} error
+ * @param {object} obj
+ * @return {SyntaxError}
+ */
+
+function normalizeJsonSyntaxError (error, obj) {
+  var keys = Object.getOwnPropertyNames(error)
+
+  for (var i = 0; i < keys.length; i++) {
+    var key = keys[i]
+    if (key !== 'stack' && key !== 'message') {
+      delete error[key]
+    }
+  }
+
+  // replace stack before message for Node.js 0.10 and below
+  error.stack = obj.stack.replace(error.message, obj.message)
+  error.message = obj.message
+
+  return error
+}
+
+/**
+ * Get the simple type checker.
+ *
+ * @param {string} type
+ * @return {function}
+ */
+
+function typeChecker (type) {
+  return function checkType (req) {
+    return Boolean(typeis(req, type))
+  }
+}
diff --git a/server/node_modules/body-parser/lib/types/raw.js b/server/node_modules/body-parser/lib/types/raw.js
new file mode 100644
index 0000000..f5d1b67
--- /dev/null
+++ b/server/node_modules/body-parser/lib/types/raw.js
@@ -0,0 +1,101 @@
+/*!
+ * body-parser
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ */
+
+var bytes = require('bytes')
+var debug = require('debug')('body-parser:raw')
+var read = require('../read')
+var typeis = require('type-is')
+
+/**
+ * Module exports.
+ */
+
+module.exports = raw
+
+/**
+ * Create a middleware to parse raw bodies.
+ *
+ * @param {object} [options]
+ * @return {function}
+ * @api public
+ */
+
+function raw (options) {
+  var opts = options || {}
+
+  var inflate = opts.inflate !== false
+  var limit = typeof opts.limit !== 'number'
+    ? bytes.parse(opts.limit || '100kb')
+    : opts.limit
+  var type = opts.type || 'application/octet-stream'
+  var verify = opts.verify || false
+
+  if (verify !== false && typeof verify !== 'function') {
+    throw new TypeError('option verify must be function')
+  }
+
+  // create the appropriate type checking function
+  var shouldParse = typeof type !== 'function'
+    ? typeChecker(type)
+    : type
+
+  function parse (buf) {
+    return buf
+  }
+
+  return function rawParser (req, res, next) {
+    if (req._body) {
+      debug('body already parsed')
+      next()
+      return
+    }
+
+    req.body = req.body || {}
+
+    // skip requests without bodies
+    if (!typeis.hasBody(req)) {
+      debug('skip empty body')
+      next()
+      return
+    }
+
+    debug('content-type %j', req.headers['content-type'])
+
+    // determine if request should be parsed
+    if (!shouldParse(req)) {
+      debug('skip parsing')
+      next()
+      return
+    }
+
+    // read
+    read(req, res, next, parse, debug, {
+      encoding: null,
+      inflate: inflate,
+      limit: limit,
+      verify: verify
+    })
+  }
+}
+
+/**
+ * Get the simple type checker.
+ *
+ * @param {string} type
+ * @return {function}
+ */
+
+function typeChecker (type) {
+  return function checkType (req) {
+    return Boolean(typeis(req, type))
+  }
+}
diff --git a/server/node_modules/body-parser/lib/types/text.js b/server/node_modules/body-parser/lib/types/text.js
new file mode 100644
index 0000000..083a009
--- /dev/null
+++ b/server/node_modules/body-parser/lib/types/text.js
@@ -0,0 +1,121 @@
+/*!
+ * body-parser
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ */
+
+var bytes = require('bytes')
+var contentType = require('content-type')
+var debug = require('debug')('body-parser:text')
+var read = require('../read')
+var typeis = require('type-is')
+
+/**
+ * Module exports.
+ */
+
+module.exports = text
+
+/**
+ * Create a middleware to parse text bodies.
+ *
+ * @param {object} [options]
+ * @return {function}
+ * @api public
+ */
+
+function text (options) {
+  var opts = options || {}
+
+  var defaultCharset = opts.defaultCharset || 'utf-8'
+  var inflate = opts.inflate !== false
+  var limit = typeof opts.limit !== 'number'
+    ? bytes.parse(opts.limit || '100kb')
+    : opts.limit
+  var type = opts.type || 'text/plain'
+  var verify = opts.verify || false
+
+  if (verify !== false && typeof verify !== 'function') {
+    throw new TypeError('option verify must be function')
+  }
+
+  // create the appropriate type checking function
+  var shouldParse = typeof type !== 'function'
+    ? typeChecker(type)
+    : type
+
+  function parse (buf) {
+    return buf
+  }
+
+  return function textParser (req, res, next) {
+    if (req._body) {
+      debug('body already parsed')
+      next()
+      return
+    }
+
+    req.body = req.body || {}
+
+    // skip requests without bodies
+    if (!typeis.hasBody(req)) {
+      debug('skip empty body')
+      next()
+      return
+    }
+
+    debug('content-type %j', req.headers['content-type'])
+
+    // determine if request should be parsed
+    if (!shouldParse(req)) {
+      debug('skip parsing')
+      next()
+      return
+    }
+
+    // get charset
+    var charset = getCharset(req) || defaultCharset
+
+    // read
+    read(req, res, next, parse, debug, {
+      encoding: charset,
+      inflate: inflate,
+      limit: limit,
+      verify: verify
+    })
+  }
+}
+
+/**
+ * Get the charset of a request.
+ *
+ * @param {object} req
+ * @api private
+ */
+
+function getCharset (req) {
+  try {
+    return (contentType.parse(req).parameters.charset || '').toLowerCase()
+  } catch (e) {
+    return undefined
+  }
+}
+
+/**
+ * Get the simple type checker.
+ *
+ * @param {string} type
+ * @return {function}
+ */
+
+function typeChecker (type) {
+  return function checkType (req) {
+    return Boolean(typeis(req, type))
+  }
+}
diff --git a/server/node_modules/body-parser/lib/types/urlencoded.js b/server/node_modules/body-parser/lib/types/urlencoded.js
new file mode 100644
index 0000000..832992c
--- /dev/null
+++ b/server/node_modules/body-parser/lib/types/urlencoded.js
@@ -0,0 +1,300 @@
+/*!
+ * body-parser
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var bytes = require('bytes')
+var contentType = require('content-type')
+var createError = require('http-errors')
+var debug = require('debug')('body-parser:urlencoded')
+var deprecate = require('depd')('body-parser')
+var read = require('../read')
+var typeis = require('type-is')
+
+/**
+ * Module exports.
+ */
+
+module.exports = urlencoded
+
+/**
+ * Cache of parser modules.
+ */
+
+var parsers = Object.create(null)
+
+/**
+ * Create a middleware to parse urlencoded bodies.
+ *
+ * @param {object} [options]
+ * @return {function}
+ * @public
+ */
+
+function urlencoded (options) {
+  var opts = options || {}
+
+  // notice because option default will flip in next major
+  if (opts.extended === undefined) {
+    deprecate('undefined extended: provide extended option')
+  }
+
+  var extended = opts.extended !== false
+  var inflate = opts.inflate !== false
+  var limit = typeof opts.limit !== 'number'
+    ? bytes.parse(opts.limit || '100kb')
+    : opts.limit
+  var type = opts.type || 'application/x-www-form-urlencoded'
+  var verify = opts.verify || false
+
+  if (verify !== false && typeof verify !== 'function') {
+    throw new TypeError('option verify must be function')
+  }
+
+  // create the appropriate query parser
+  var queryparse = extended
+    ? extendedparser(opts)
+    : simpleparser(opts)
+
+  // create the appropriate type checking function
+  var shouldParse = typeof type !== 'function'
+    ? typeChecker(type)
+    : type
+
+  function parse (body) {
+    return body.length
+      ? queryparse(body)
+      : {}
+  }
+
+  return function urlencodedParser (req, res, next) {
+    if (req._body) {
+      debug('body already parsed')
+      next()
+      return
+    }
+
+    req.body = req.body || {}
+
+    // skip requests without bodies
+    if (!typeis.hasBody(req)) {
+      debug('skip empty body')
+      next()
+      return
+    }
+
+    debug('content-type %j', req.headers['content-type'])
+
+    // determine if request should be parsed
+    if (!shouldParse(req)) {
+      debug('skip parsing')
+      next()
+      return
+    }
+
+    // assert charset
+    var charset = getCharset(req) || 'utf-8'
+    if (charset !== 'utf-8') {
+      debug('invalid charset')
+      next(createError(415, 'unsupported charset "' + charset.toUpperCase() + '"', {
+        charset: charset,
+        type: 'charset.unsupported'
+      }))
+      return
+    }
+
+    // read
+    read(req, res, next, parse, debug, {
+      debug: debug,
+      encoding: charset,
+      inflate: inflate,
+      limit: limit,
+      verify: verify
+    })
+  }
+}
+
+/**
+ * Get the extended query parser.
+ *
+ * @param {object} options
+ */
+
+function extendedparser (options) {
+  var parameterLimit = options.parameterLimit !== undefined
+    ? options.parameterLimit
+    : 1000
+  var depth = options.depth !== undefined ? options.depth : 32
+  var parse = parser('qs')
+
+  if (isNaN(parameterLimit) || parameterLimit < 1) {
+    throw new TypeError('option parameterLimit must be a positive number')
+  }
+
+  if (isNaN(depth) || depth < 0) {
+    throw new TypeError('option depth must be a zero or a positive number')
+  }
+
+  if (isFinite(parameterLimit)) {
+    parameterLimit = parameterLimit | 0
+  }
+
+  return function queryparse (body) {
+    var paramCount = parameterCount(body, parameterLimit)
+
+    if (paramCount === undefined) {
+      debug('too many parameters')
+      throw createError(413, 'too many parameters', {
+        type: 'parameters.too.many'
+      })
+    }
+
+    var arrayLimit = Math.max(100, paramCount)
+
+    debug('parse extended urlencoding')
+    try {
+      return parse(body, {
+        allowPrototypes: true,
+        arrayLimit: arrayLimit,
+        depth: depth,
+        strictDepth: true,
+        parameterLimit: parameterLimit
+      })
+    } catch (err) {
+      if (err instanceof RangeError) {
+        throw createError(400, 'The input exceeded the depth', {
+          type: 'querystring.parse.rangeError'
+        })
+      } else {
+        throw err
+      }
+    }
+  }
+}
+
+/**
+ * Get the charset of a request.
+ *
+ * @param {object} req
+ * @api private
+ */
+
+function getCharset (req) {
+  try {
+    return (contentType.parse(req).parameters.charset || '').toLowerCase()
+  } catch (e) {
+    return undefined
+  }
+}
+
+/**
+ * Count the number of parameters, stopping once limit reached
+ *
+ * @param {string} body
+ * @param {number} limit
+ * @api private
+ */
+
+function parameterCount (body, limit) {
+  var count = 0
+  var index = 0
+
+  while ((index = body.indexOf('&', index)) !== -1) {
+    count++
+    index++
+
+    if (count === limit) {
+      return undefined
+    }
+  }
+
+  return count
+}
+
+/**
+ * Get parser for module name dynamically.
+ *
+ * @param {string} name
+ * @return {function}
+ * @api private
+ */
+
+function parser (name) {
+  var mod = parsers[name]
+
+  if (mod !== undefined) {
+    return mod.parse
+  }
+
+  // this uses a switch for static require analysis
+  switch (name) {
+    case 'qs':
+      mod = require('qs')
+      break
+    case 'querystring':
+      mod = require('querystring')
+      break
+  }
+
+  // store to prevent invoking require()
+  parsers[name] = mod
+
+  return mod.parse
+}
+
+/**
+ * Get the simple query parser.
+ *
+ * @param {object} options
+ */
+
+function simpleparser (options) {
+  var parameterLimit = options.parameterLimit !== undefined
+    ? options.parameterLimit
+    : 1000
+  var parse = parser('querystring')
+
+  if (isNaN(parameterLimit) || parameterLimit < 1) {
+    throw new TypeError('option parameterLimit must be a positive number')
+  }
+
+  if (isFinite(parameterLimit)) {
+    parameterLimit = parameterLimit | 0
+  }
+
+  return function queryparse (body) {
+    var paramCount = parameterCount(body, parameterLimit)
+
+    if (paramCount === undefined) {
+      debug('too many parameters')
+      throw createError(413, 'too many parameters', {
+        type: 'parameters.too.many'
+      })
+    }
+
+    debug('parse urlencoding')
+    return parse(body, undefined, undefined, { maxKeys: parameterLimit })
+  }
+}
+
+/**
+ * Get the simple type checker.
+ *
+ * @param {string} type
+ * @return {function}
+ */
+
+function typeChecker (type) {
+  return function checkType (req) {
+    return Boolean(typeis(req, type))
+  }
+}
diff --git a/server/node_modules/body-parser/package.json b/server/node_modules/body-parser/package.json
new file mode 100644
index 0000000..c8e61c1
--- /dev/null
+++ b/server/node_modules/body-parser/package.json
@@ -0,0 +1,55 @@
+{
+  "name": "body-parser",
+  "description": "Node.js body parsing middleware",
+  "version": "1.20.4",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "license": "MIT",
+  "repository": "expressjs/body-parser",
+  "dependencies": {
+    "bytes": "~3.1.2",
+    "content-type": "~1.0.5",
+    "debug": "2.6.9",
+    "depd": "2.0.0",
+    "destroy": "~1.2.0",
+    "http-errors": "~2.0.1",
+    "iconv-lite": "~0.4.24",
+    "on-finished": "~2.4.1",
+    "qs": "~6.14.0",
+    "raw-body": "~2.5.3",
+    "type-is": "~1.6.18",
+    "unpipe": "~1.0.0"
+  },
+  "devDependencies": {
+    "eslint": "8.34.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.27.5",
+    "eslint-plugin-markdown": "3.0.0",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "6.1.1",
+    "eslint-plugin-standard": "4.1.0",
+    "methods": "1.1.2",
+    "mocha": "10.2.0",
+    "nyc": "15.1.0",
+    "safe-buffer": "5.2.1",
+    "supertest": "6.3.3"
+  },
+  "files": [
+    "lib/",
+    "LICENSE",
+    "HISTORY.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8",
+    "npm": "1.2.8000 || >= 1.4.16"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --require test/support/env --reporter spec --check-leaks --bail test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/brace-expansion/LICENSE b/server/node_modules/brace-expansion/LICENSE
new file mode 100644
index 0000000..de32266
--- /dev/null
+++ b/server/node_modules/brace-expansion/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/brace-expansion/README.md b/server/node_modules/brace-expansion/README.md
new file mode 100644
index 0000000..6b4e0e1
--- /dev/null
+++ b/server/node_modules/brace-expansion/README.md
@@ -0,0 +1,129 @@
+# brace-expansion
+
+[Brace expansion](https://www.gnu.org/software/bash/manual/html_node/Brace-Expansion.html), 
+as known from sh/bash, in JavaScript.
+
+[![build status](https://secure.travis-ci.org/juliangruber/brace-expansion.svg)](http://travis-ci.org/juliangruber/brace-expansion)
+[![downloads](https://img.shields.io/npm/dm/brace-expansion.svg)](https://www.npmjs.org/package/brace-expansion)
+[![Greenkeeper badge](https://badges.greenkeeper.io/juliangruber/brace-expansion.svg)](https://greenkeeper.io/)
+
+[![testling badge](https://ci.testling.com/juliangruber/brace-expansion.png)](https://ci.testling.com/juliangruber/brace-expansion)
+
+## Example
+
+```js
+var expand = require('brace-expansion');
+
+expand('file-{a,b,c}.jpg')
+// => ['file-a.jpg', 'file-b.jpg', 'file-c.jpg']
+
+expand('-v{,,}')
+// => ['-v', '-v', '-v']
+
+expand('file{0..2}.jpg')
+// => ['file0.jpg', 'file1.jpg', 'file2.jpg']
+
+expand('file-{a..c}.jpg')
+// => ['file-a.jpg', 'file-b.jpg', 'file-c.jpg']
+
+expand('file{2..0}.jpg')
+// => ['file2.jpg', 'file1.jpg', 'file0.jpg']
+
+expand('file{0..4..2}.jpg')
+// => ['file0.jpg', 'file2.jpg', 'file4.jpg']
+
+expand('file-{a..e..2}.jpg')
+// => ['file-a.jpg', 'file-c.jpg', 'file-e.jpg']
+
+expand('file{00..10..5}.jpg')
+// => ['file00.jpg', 'file05.jpg', 'file10.jpg']
+
+expand('{{A..C},{a..c}}')
+// => ['A', 'B', 'C', 'a', 'b', 'c']
+
+expand('ppp{,config,oe{,conf}}')
+// => ['ppp', 'pppconfig', 'pppoe', 'pppoeconf']
+```
+
+## API
+
+```js
+var expand = require('brace-expansion');
+```
+
+### var expanded = expand(str)
+
+Return an array of all possible and valid expansions of `str`. If none are
+found, `[str]` is returned.
+
+Valid expansions are:
+
+```js
+/^(.*,)+(.+)?$/
+// {a,b,...}
+```
+
+A comma separated list of options, like `{a,b}` or `{a,{b,c}}` or `{,a,}`.
+
+```js
+/^-?\d+\.\.-?\d+(\.\.-?\d+)?$/
+// {x..y[..incr]}
+```
+
+A numeric sequence from `x` to `y` inclusive, with optional increment.
+If `x` or `y` start with a leading `0`, all the numbers will be padded
+to have equal length. Negative numbers and backwards iteration work too.
+
+```js
+/^-?\d+\.\.-?\d+(\.\.-?\d+)?$/
+// {x..y[..incr]}
+```
+
+An alphabetic sequence from `x` to `y` inclusive, with optional increment.
+`x` and `y` must be exactly one character, and if given, `incr` must be a
+number.
+
+For compatibility reasons, the string `${` is not eligible for brace expansion.
+
+## Installation
+
+With [npm](https://npmjs.org) do:
+
+```bash
+npm install brace-expansion
+```
+
+## Contributors
+
+- [Julian Gruber](https://github.com/juliangruber)
+- [Isaac Z. Schlueter](https://github.com/isaacs)
+
+## Sponsors
+
+This module is proudly supported by my [Sponsors](https://github.com/juliangruber/sponsors)!
+
+Do you want to support modules like this to improve their quality, stability and weigh in on new features? Then please consider donating to my [Patreon](https://www.patreon.com/juliangruber). Not sure how much of my modules you're using? Try [feross/thanks](https://github.com/feross/thanks)!
+
+## License
+
+(MIT)
+
+Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/brace-expansion/index.js b/server/node_modules/brace-expansion/index.js
new file mode 100644
index 0000000..bd19fe6
--- /dev/null
+++ b/server/node_modules/brace-expansion/index.js
@@ -0,0 +1,201 @@
+var concatMap = require('concat-map');
+var balanced = require('balanced-match');
+
+module.exports = expandTop;
+
+var escSlash = '\0SLASH'+Math.random()+'\0';
+var escOpen = '\0OPEN'+Math.random()+'\0';
+var escClose = '\0CLOSE'+Math.random()+'\0';
+var escComma = '\0COMMA'+Math.random()+'\0';
+var escPeriod = '\0PERIOD'+Math.random()+'\0';
+
+function numeric(str) {
+  return parseInt(str, 10) == str
+    ? parseInt(str, 10)
+    : str.charCodeAt(0);
+}
+
+function escapeBraces(str) {
+  return str.split('\\\\').join(escSlash)
+            .split('\\{').join(escOpen)
+            .split('\\}').join(escClose)
+            .split('\\,').join(escComma)
+            .split('\\.').join(escPeriod);
+}
+
+function unescapeBraces(str) {
+  return str.split(escSlash).join('\\')
+            .split(escOpen).join('{')
+            .split(escClose).join('}')
+            .split(escComma).join(',')
+            .split(escPeriod).join('.');
+}
+
+
+// Basically just str.split(","), but handling cases
+// where we have nested braced sections, which should be
+// treated as individual members, like {a,{b,c},d}
+function parseCommaParts(str) {
+  if (!str)
+    return [''];
+
+  var parts = [];
+  var m = balanced('{', '}', str);
+
+  if (!m)
+    return str.split(',');
+
+  var pre = m.pre;
+  var body = m.body;
+  var post = m.post;
+  var p = pre.split(',');
+
+  p[p.length-1] += '{' + body + '}';
+  var postParts = parseCommaParts(post);
+  if (post.length) {
+    p[p.length-1] += postParts.shift();
+    p.push.apply(p, postParts);
+  }
+
+  parts.push.apply(parts, p);
+
+  return parts;
+}
+
+function expandTop(str) {
+  if (!str)
+    return [];
+
+  // I don't know why Bash 4.3 does this, but it does.
+  // Anything starting with {} will have the first two bytes preserved
+  // but *only* at the top level, so {},a}b will not expand to anything,
+  // but a{},b}c will be expanded to [a}c,abc].
+  // One could argue that this is a bug in Bash, but since the goal of
+  // this module is to match Bash's rules, we escape a leading {}
+  if (str.substr(0, 2) === '{}') {
+    str = '\\{\\}' + str.substr(2);
+  }
+
+  return expand(escapeBraces(str), true).map(unescapeBraces);
+}
+
+function identity(e) {
+  return e;
+}
+
+function embrace(str) {
+  return '{' + str + '}';
+}
+function isPadded(el) {
+  return /^-?0\d/.test(el);
+}
+
+function lte(i, y) {
+  return i <= y;
+}
+function gte(i, y) {
+  return i >= y;
+}
+
+function expand(str, isTop) {
+  var expansions = [];
+
+  var m = balanced('{', '}', str);
+  if (!m || /\$$/.test(m.pre)) return [str];
+
+  var isNumericSequence = /^-?\d+\.\.-?\d+(?:\.\.-?\d+)?$/.test(m.body);
+  var isAlphaSequence = /^[a-zA-Z]\.\.[a-zA-Z](?:\.\.-?\d+)?$/.test(m.body);
+  var isSequence = isNumericSequence || isAlphaSequence;
+  var isOptions = m.body.indexOf(',') >= 0;
+  if (!isSequence && !isOptions) {
+    // {a},b}
+    if (m.post.match(/,(?!,).*\}/)) {
+      str = m.pre + '{' + m.body + escClose + m.post;
+      return expand(str);
+    }
+    return [str];
+  }
+
+  var n;
+  if (isSequence) {
+    n = m.body.split(/\.\./);
+  } else {
+    n = parseCommaParts(m.body);
+    if (n.length === 1) {
+      // x{{a,b}}y ==> x{a}y x{b}y
+      n = expand(n[0], false).map(embrace);
+      if (n.length === 1) {
+        var post = m.post.length
+          ? expand(m.post, false)
+          : [''];
+        return post.map(function(p) {
+          return m.pre + n[0] + p;
+        });
+      }
+    }
+  }
+
+  // at this point, n is the parts, and we know it's not a comma set
+  // with a single entry.
+
+  // no need to expand pre, since it is guaranteed to be free of brace-sets
+  var pre = m.pre;
+  var post = m.post.length
+    ? expand(m.post, false)
+    : [''];
+
+  var N;
+
+  if (isSequence) {
+    var x = numeric(n[0]);
+    var y = numeric(n[1]);
+    var width = Math.max(n[0].length, n[1].length)
+    var incr = n.length == 3
+      ? Math.abs(numeric(n[2]))
+      : 1;
+    var test = lte;
+    var reverse = y < x;
+    if (reverse) {
+      incr *= -1;
+      test = gte;
+    }
+    var pad = n.some(isPadded);
+
+    N = [];
+
+    for (var i = x; test(i, y); i += incr) {
+      var c;
+      if (isAlphaSequence) {
+        c = String.fromCharCode(i);
+        if (c === '\\')
+          c = '';
+      } else {
+        c = String(i);
+        if (pad) {
+          var need = width - c.length;
+          if (need > 0) {
+            var z = new Array(need + 1).join('0');
+            if (i < 0)
+              c = '-' + z + c.slice(1);
+            else
+              c = z + c;
+          }
+        }
+      }
+      N.push(c);
+    }
+  } else {
+    N = concatMap(n, function(el) { return expand(el, false) });
+  }
+
+  for (var j = 0; j < N.length; j++) {
+    for (var k = 0; k < post.length; k++) {
+      var expansion = pre + N[j] + post[k];
+      if (!isTop || isSequence || expansion)
+        expansions.push(expansion);
+    }
+  }
+
+  return expansions;
+}
+
diff --git a/server/node_modules/brace-expansion/package.json b/server/node_modules/brace-expansion/package.json
new file mode 100644
index 0000000..3447888
--- /dev/null
+++ b/server/node_modules/brace-expansion/package.json
@@ -0,0 +1,50 @@
+{
+  "name": "brace-expansion",
+  "description": "Brace expansion as known from sh/bash",
+  "version": "1.1.12",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/juliangruber/brace-expansion.git"
+  },
+  "homepage": "https://github.com/juliangruber/brace-expansion",
+  "main": "index.js",
+  "scripts": {
+    "test": "tape test/*.js",
+    "gentest": "bash test/generate.sh",
+    "bench": "matcha test/perf/bench.js"
+  },
+  "dependencies": {
+    "balanced-match": "^1.0.0",
+    "concat-map": "0.0.1"
+  },
+  "devDependencies": {
+    "matcha": "^0.7.0",
+    "tape": "^4.6.0"
+  },
+  "keywords": [],
+  "author": {
+    "name": "Julian Gruber",
+    "email": "mail@juliangruber.com",
+    "url": "http://juliangruber.com"
+  },
+  "license": "MIT",
+  "testling": {
+    "files": "test/*.js",
+    "browsers": [
+      "ie/8..latest",
+      "firefox/20..latest",
+      "firefox/nightly",
+      "chrome/25..latest",
+      "chrome/canary",
+      "opera/12..latest",
+      "opera/next",
+      "safari/5.1..latest",
+      "ipad/6.0..latest",
+      "iphone/6.0..latest",
+      "android-browser/4.2..latest"
+    ]
+  },
+  "publishConfig": {
+    "tag": "1.x"
+  }
+}
diff --git a/server/node_modules/buffer-from/LICENSE b/server/node_modules/buffer-from/LICENSE
new file mode 100644
index 0000000..e4bf1d6
--- /dev/null
+++ b/server/node_modules/buffer-from/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2016, 2018 Linus Unnebäck
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/buffer-from/index.js b/server/node_modules/buffer-from/index.js
new file mode 100644
index 0000000..e1a58b5
--- /dev/null
+++ b/server/node_modules/buffer-from/index.js
@@ -0,0 +1,72 @@
+/* eslint-disable node/no-deprecated-api */
+
+var toString = Object.prototype.toString
+
+var isModern = (
+  typeof Buffer !== 'undefined' &&
+  typeof Buffer.alloc === 'function' &&
+  typeof Buffer.allocUnsafe === 'function' &&
+  typeof Buffer.from === 'function'
+)
+
+function isArrayBuffer (input) {
+  return toString.call(input).slice(8, -1) === 'ArrayBuffer'
+}
+
+function fromArrayBuffer (obj, byteOffset, length) {
+  byteOffset >>>= 0
+
+  var maxLength = obj.byteLength - byteOffset
+
+  if (maxLength < 0) {
+    throw new RangeError("'offset' is out of bounds")
+  }
+
+  if (length === undefined) {
+    length = maxLength
+  } else {
+    length >>>= 0
+
+    if (length > maxLength) {
+      throw new RangeError("'length' is out of bounds")
+    }
+  }
+
+  return isModern
+    ? Buffer.from(obj.slice(byteOffset, byteOffset + length))
+    : new Buffer(new Uint8Array(obj.slice(byteOffset, byteOffset + length)))
+}
+
+function fromString (string, encoding) {
+  if (typeof encoding !== 'string' || encoding === '') {
+    encoding = 'utf8'
+  }
+
+  if (!Buffer.isEncoding(encoding)) {
+    throw new TypeError('"encoding" must be a valid string encoding')
+  }
+
+  return isModern
+    ? Buffer.from(string, encoding)
+    : new Buffer(string, encoding)
+}
+
+function bufferFrom (value, encodingOrOffset, length) {
+  if (typeof value === 'number') {
+    throw new TypeError('"value" argument must not be a number')
+  }
+
+  if (isArrayBuffer(value)) {
+    return fromArrayBuffer(value, encodingOrOffset, length)
+  }
+
+  if (typeof value === 'string') {
+    return fromString(value, encodingOrOffset)
+  }
+
+  return isModern
+    ? Buffer.from(value)
+    : new Buffer(value)
+}
+
+module.exports = bufferFrom
diff --git a/server/node_modules/buffer-from/package.json b/server/node_modules/buffer-from/package.json
new file mode 100644
index 0000000..6ac5327
--- /dev/null
+++ b/server/node_modules/buffer-from/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "buffer-from",
+  "version": "1.1.2",
+  "license": "MIT",
+  "repository": "LinusU/buffer-from",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "test": "standard && node test"
+  },
+  "devDependencies": {
+    "standard": "^12.0.1"
+  },
+  "keywords": [
+    "buffer",
+    "buffer from"
+  ]
+}
diff --git a/server/node_modules/buffer-from/readme.md b/server/node_modules/buffer-from/readme.md
new file mode 100644
index 0000000..9880a55
--- /dev/null
+++ b/server/node_modules/buffer-from/readme.md
@@ -0,0 +1,69 @@
+# Buffer From
+
+A [ponyfill](https://ponyfill.com) for `Buffer.from`, uses native implementation if available.
+
+## Installation
+
+```sh
+npm install --save buffer-from
+```
+
+## Usage
+
+```js
+const bufferFrom = require('buffer-from')
+
+console.log(bufferFrom([1, 2, 3, 4]))
+//=> <Buffer 01 02 03 04>
+
+const arr = new Uint8Array([1, 2, 3, 4])
+console.log(bufferFrom(arr.buffer, 1, 2))
+//=> <Buffer 02 03>
+
+console.log(bufferFrom('test', 'utf8'))
+//=> <Buffer 74 65 73 74>
+
+const buf = bufferFrom('test')
+console.log(bufferFrom(buf))
+//=> <Buffer 74 65 73 74>
+```
+
+## API
+
+### bufferFrom(array)
+
+- `array` <Array>
+
+Allocates a new `Buffer` using an `array` of octets.
+
+### bufferFrom(arrayBuffer[, byteOffset[, length]])
+
+- `arrayBuffer` <ArrayBuffer> The `.buffer` property of a TypedArray or ArrayBuffer
+- `byteOffset` <Integer> Where to start copying from `arrayBuffer`. **Default:** `0`
+- `length` <Integer> How many bytes to copy from `arrayBuffer`. **Default:** `arrayBuffer.length - byteOffset`
+
+When passed a reference to the `.buffer` property of a TypedArray instance, the
+newly created `Buffer` will share the same allocated memory as the TypedArray.
+
+The optional `byteOffset` and `length` arguments specify a memory range within
+the `arrayBuffer` that will be shared by the `Buffer`.
+
+### bufferFrom(buffer)
+
+- `buffer` <Buffer> An existing `Buffer` to copy data from
+
+Copies the passed `buffer` data onto a new `Buffer` instance.
+
+### bufferFrom(string[, encoding])
+
+- `string` <String> A string to encode.
+- `encoding` <String> The encoding of `string`. **Default:** `'utf8'`
+
+Creates a new `Buffer` containing the given JavaScript string `string`. If
+provided, the `encoding` parameter identifies the character encoding of
+`string`.
+
+## See also
+
+- [buffer-alloc](https://github.com/LinusU/buffer-alloc) A ponyfill for `Buffer.alloc`
+- [buffer-alloc-unsafe](https://github.com/LinusU/buffer-alloc-unsafe) A ponyfill for `Buffer.allocUnsafe`
diff --git a/server/node_modules/buffer/AUTHORS.md b/server/node_modules/buffer/AUTHORS.md
new file mode 100644
index 0000000..22eb171
--- /dev/null
+++ b/server/node_modules/buffer/AUTHORS.md
@@ -0,0 +1,70 @@
+# Authors
+
+#### Ordered by first contribution.
+
+- Romain Beauxis (toots@rastageeks.org)
+- Tobias Koppers (tobias.koppers@googlemail.com)
+- Janus (ysangkok@gmail.com)
+- Rainer Dreyer (rdrey1@gmail.com)
+- Tõnis Tiigi (tonistiigi@gmail.com)
+- James Halliday (mail@substack.net)
+- Michael Williamson (mike@zwobble.org)
+- elliottcable (github@elliottcable.name)
+- rafael (rvalle@livelens.net)
+- Andrew Kelley (superjoe30@gmail.com)
+- Andreas Madsen (amwebdk@gmail.com)
+- Mike Brevoort (mike.brevoort@pearson.com)
+- Brian White (mscdex@mscdex.net)
+- Feross Aboukhadijeh (feross@feross.org)
+- Ruben Verborgh (ruben@verborgh.org)
+- eliang (eliang.cs@gmail.com)
+- Jesse Tane (jesse.tane@gmail.com)
+- Alfonso Boza (alfonso@cloud.com)
+- Mathias Buus (mathiasbuus@gmail.com)
+- Devon Govett (devongovett@gmail.com)
+- Daniel Cousens (github@dcousens.com)
+- Joseph Dykstra (josephdykstra@gmail.com)
+- Parsha Pourkhomami (parshap+git@gmail.com)
+- Damjan Košir (damjan.kosir@gmail.com)
+- daverayment (dave.rayment@gmail.com)
+- kawanet (u-suke@kawa.net)
+- Linus Unnebäck (linus@folkdatorn.se)
+- Nolan Lawson (nolan.lawson@gmail.com)
+- Calvin Metcalf (calvin.metcalf@gmail.com)
+- Koki Takahashi (hakatasiloving@gmail.com)
+- Guy Bedford (guybedford@gmail.com)
+- Jan Schär (jscissr@gmail.com)
+- RaulTsc (tomescu.raul@gmail.com)
+- Matthieu Monsch (monsch@alum.mit.edu)
+- Dan Ehrenberg (littledan@chromium.org)
+- Kirill Fomichev (fanatid@ya.ru)
+- Yusuke Kawasaki (u-suke@kawa.net)
+- DC (dcposch@dcpos.ch)
+- John-David Dalton (john.david.dalton@gmail.com)
+- adventure-yunfei (adventure030@gmail.com)
+- Emil Bay (github@tixz.dk)
+- Sam Sudar (sudar.sam@gmail.com)
+- Volker Mische (volker.mische@gmail.com)
+- David Walton (support@geekstocks.com)
+- Сковорода Никита Андреевич (chalkerx@gmail.com)
+- greenkeeper[bot] (greenkeeper[bot]@users.noreply.github.com)
+- ukstv (sergey.ukustov@machinomy.com)
+- Renée Kooi (renee@kooi.me)
+- ranbochen (ranbochen@qq.com)
+- Vladimir Borovik (bobahbdb@gmail.com)
+- greenkeeper[bot] (23040076+greenkeeper[bot]@users.noreply.github.com)
+- kumavis (aaron@kumavis.me)
+- Sergey Ukustov (sergey.ukustov@machinomy.com)
+- Fei Liu (liu.feiwood@gmail.com)
+- Blaine Bublitz (blaine.bublitz@gmail.com)
+- clement (clement@seald.io)
+- Koushik Dutta (koushd@gmail.com)
+- Jordan Harband (ljharb@gmail.com)
+- Niklas Mischkulnig (mischnic@users.noreply.github.com)
+- Nikolai Vavilov (vvnicholas@gmail.com)
+- Fedor Nezhivoi (gyzerok@users.noreply.github.com)
+- Peter Newman (peternewman@users.noreply.github.com)
+- mathmakgakpak (44949126+mathmakgakpak@users.noreply.github.com)
+- jkkang (jkkang@smartauth.kr)
+
+#### Generated by bin/update-authors.sh.
diff --git a/server/node_modules/buffer/LICENSE b/server/node_modules/buffer/LICENSE
new file mode 100644
index 0000000..d6bf75d
--- /dev/null
+++ b/server/node_modules/buffer/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Feross Aboukhadijeh, and other contributors.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/buffer/README.md b/server/node_modules/buffer/README.md
new file mode 100644
index 0000000..9a23d7c
--- /dev/null
+++ b/server/node_modules/buffer/README.md
@@ -0,0 +1,410 @@
+# buffer [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![downloads][downloads-image]][downloads-url] [![javascript style guide][standard-image]][standard-url]
+
+[travis-image]: https://img.shields.io/travis/feross/buffer/master.svg
+[travis-url]: https://travis-ci.org/feross/buffer
+[npm-image]: https://img.shields.io/npm/v/buffer.svg
+[npm-url]: https://npmjs.org/package/buffer
+[downloads-image]: https://img.shields.io/npm/dm/buffer.svg
+[downloads-url]: https://npmjs.org/package/buffer
+[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
+[standard-url]: https://standardjs.com
+
+#### The buffer module from [node.js](https://nodejs.org/), for the browser.
+
+[![saucelabs][saucelabs-image]][saucelabs-url]
+
+[saucelabs-image]: https://saucelabs.com/browser-matrix/buffer.svg
+[saucelabs-url]: https://saucelabs.com/u/buffer
+
+With [browserify](http://browserify.org), simply `require('buffer')` or use the `Buffer` global and you will get this module.
+
+The goal is to provide an API that is 100% identical to
+[node's Buffer API](https://nodejs.org/api/buffer.html). Read the
+[official docs](https://nodejs.org/api/buffer.html) for the full list of properties,
+instance methods, and class methods that are supported.
+
+## features
+
+- Manipulate binary data like a boss, in all browsers!
+- Super fast. Backed by Typed Arrays (`Uint8Array`/`ArrayBuffer`, not `Object`)
+- Extremely small bundle size (**6.75KB minified + gzipped**, 51.9KB with comments)
+- Excellent browser support (Chrome, Firefox, Edge, Safari 9+, IE 11, iOS 9+, Android, etc.)
+- Preserves Node API exactly, with one minor difference (see below)
+- Square-bracket `buf[4]` notation works!
+- Does not modify any browser prototypes or put anything on `window`
+- Comprehensive test suite (including all buffer tests from node.js core)
+
+## install
+
+To use this module directly (without browserify), install it:
+
+```bash
+npm install buffer
+```
+
+This module was previously called **native-buffer-browserify**, but please use **buffer**
+from now on.
+
+If you do not use a bundler, you can use the [standalone script](https://bundle.run/buffer).
+
+## usage
+
+The module's API is identical to node's `Buffer` API. Read the
+[official docs](https://nodejs.org/api/buffer.html) for the full list of properties,
+instance methods, and class methods that are supported.
+
+As mentioned above, `require('buffer')` or use the `Buffer` global with
+[browserify](http://browserify.org) and this module will automatically be included
+in your bundle. Almost any npm module will work in the browser, even if it assumes that
+the node `Buffer` API will be available.
+
+To depend on this module explicitly (without browserify), require it like this:
+
+```js
+var Buffer = require('buffer/').Buffer  // note: the trailing slash is important!
+```
+
+To require this module explicitly, use `require('buffer/')` which tells the node.js module
+lookup algorithm (also used by browserify) to use the **npm module** named `buffer`
+instead of the **node.js core** module named `buffer`!
+
+
+## how does it work?
+
+The Buffer constructor returns instances of `Uint8Array` that have their prototype
+changed to `Buffer.prototype`. Furthermore, `Buffer` is a subclass of `Uint8Array`,
+so the returned instances will have all the node `Buffer` methods and the
+`Uint8Array` methods. Square bracket notation works as expected -- it returns a
+single octet.
+
+The `Uint8Array` prototype remains unmodified.
+
+
+## tracking the latest node api
+
+This module tracks the Buffer API in the latest (unstable) version of node.js. The Buffer
+API is considered **stable** in the
+[node stability index](https://nodejs.org/docs/latest/api/documentation.html#documentation_stability_index),
+so it is unlikely that there will ever be breaking changes.
+Nonetheless, when/if the Buffer API changes in node, this module's API will change
+accordingly.
+
+## related packages
+
+- [`buffer-reverse`](https://www.npmjs.com/package/buffer-reverse) - Reverse a buffer
+- [`buffer-xor`](https://www.npmjs.com/package/buffer-xor) - Bitwise xor a buffer
+- [`is-buffer`](https://www.npmjs.com/package/is-buffer) - Determine if an object is a Buffer without including the whole `Buffer` package
+
+## conversion packages
+
+### convert typed array to buffer
+
+Use [`typedarray-to-buffer`](https://www.npmjs.com/package/typedarray-to-buffer) to convert any kind of typed array to a `Buffer`. Does not perform a copy, so it's super fast.
+
+### convert buffer to typed array
+
+`Buffer` is a subclass of `Uint8Array` (which is a typed array). So there is no need to explicitly convert to typed array. Just use the buffer as a `Uint8Array`.
+
+### convert blob to buffer
+
+Use [`blob-to-buffer`](https://www.npmjs.com/package/blob-to-buffer) to convert a `Blob` to a `Buffer`.
+
+### convert buffer to blob
+
+To convert a `Buffer` to a `Blob`, use the `Blob` constructor:
+
+```js
+var blob = new Blob([ buffer ])
+```
+
+Optionally, specify a mimetype:
+
+```js
+var blob = new Blob([ buffer ], { type: 'text/html' })
+```
+
+### convert arraybuffer to buffer
+
+To convert an `ArrayBuffer` to a `Buffer`, use the `Buffer.from` function. Does not perform a copy, so it's super fast.
+
+```js
+var buffer = Buffer.from(arrayBuffer)
+```
+
+### convert buffer to arraybuffer
+
+To convert a `Buffer` to an `ArrayBuffer`, use the `.buffer` property (which is present on all `Uint8Array` objects):
+
+```js
+var arrayBuffer = buffer.buffer.slice(
+  buffer.byteOffset, buffer.byteOffset + buffer.byteLength
+)
+```
+
+Alternatively, use the [`to-arraybuffer`](https://www.npmjs.com/package/to-arraybuffer) module.
+
+## performance
+
+See perf tests in `/perf`.
+
+`BrowserBuffer` is the browser `buffer` module (this repo). `Uint8Array` is included as a
+sanity check (since `BrowserBuffer` uses `Uint8Array` under the hood, `Uint8Array` will
+always be at least a bit faster). Finally, `NodeBuffer` is the node.js buffer module,
+which is included to compare against.
+
+NOTE: Performance has improved since these benchmarks were taken. PR welcome to update the README.
+
+### Chrome 38
+
+| Method | Operations | Accuracy | Sampled | Fastest |
+|:-------|:-----------|:---------|:--------|:-------:|
+| BrowserBuffer#bracket-notation | 11,457,464 ops/sec | ±0.86% | 66 | ✓ |
+| Uint8Array#bracket-notation | 10,824,332 ops/sec | ±0.74% | 65 | |
+| | | | |
+| BrowserBuffer#concat | 450,532 ops/sec | ±0.76% | 68 | |
+| Uint8Array#concat | 1,368,911 ops/sec | ±1.50% | 62 | ✓ |
+| | | | |
+| BrowserBuffer#copy(16000) | 903,001 ops/sec | ±0.96% | 67 | |
+| Uint8Array#copy(16000) | 1,422,441 ops/sec | ±1.04% | 66 | ✓ |
+| | | | |
+| BrowserBuffer#copy(16) | 11,431,358 ops/sec | ±0.46% | 69 | |
+| Uint8Array#copy(16) | 13,944,163 ops/sec | ±1.12% | 68 | ✓ |
+| | | | |
+| BrowserBuffer#new(16000) | 106,329 ops/sec | ±6.70% | 44 | |
+| Uint8Array#new(16000) | 131,001 ops/sec | ±2.85% | 31 | ✓ |
+| | | | |
+| BrowserBuffer#new(16) | 1,554,491 ops/sec | ±1.60% | 65 | |
+| Uint8Array#new(16) | 6,623,930 ops/sec | ±1.66% | 65 | ✓ |
+| | | | |
+| BrowserBuffer#readDoubleBE | 112,830 ops/sec | ±0.51% | 69 | ✓ |
+| DataView#getFloat64 | 93,500 ops/sec | ±0.57% | 68 | |
+| | | | |
+| BrowserBuffer#readFloatBE | 146,678 ops/sec | ±0.95% | 68 | ✓ |
+| DataView#getFloat32 | 99,311 ops/sec | ±0.41% | 67 | |
+| | | | |
+| BrowserBuffer#readUInt32LE | 843,214 ops/sec | ±0.70% | 69 | ✓ |
+| DataView#getUint32 | 103,024 ops/sec | ±0.64% | 67 | |
+| | | | |
+| BrowserBuffer#slice | 1,013,941 ops/sec | ±0.75% | 67 | |
+| Uint8Array#subarray | 1,903,928 ops/sec | ±0.53% | 67 | ✓ |
+| | | | |
+| BrowserBuffer#writeFloatBE | 61,387 ops/sec | ±0.90% | 67 | |
+| DataView#setFloat32 | 141,249 ops/sec | ±0.40% | 66 | ✓ |
+
+
+### Firefox 33
+
+| Method | Operations | Accuracy | Sampled | Fastest |
+|:-------|:-----------|:---------|:--------|:-------:|
+| BrowserBuffer#bracket-notation | 20,800,421 ops/sec | ±1.84% | 60 | |
+| Uint8Array#bracket-notation | 20,826,235 ops/sec | ±2.02% | 61 | ✓ |
+| | | | |
+| BrowserBuffer#concat | 153,076 ops/sec | ±2.32% | 61 | |
+| Uint8Array#concat | 1,255,674 ops/sec | ±8.65% | 52 | ✓ |
+| | | | |
+| BrowserBuffer#copy(16000) | 1,105,312 ops/sec | ±1.16% | 63 | |
+| Uint8Array#copy(16000) | 1,615,911 ops/sec | ±0.55% | 66 | ✓ |
+| | | | |
+| BrowserBuffer#copy(16) | 16,357,599 ops/sec | ±0.73% | 68 | |
+| Uint8Array#copy(16) | 31,436,281 ops/sec | ±1.05% | 68 | ✓ |
+| | | | |
+| BrowserBuffer#new(16000) | 52,995 ops/sec | ±6.01% | 35 | |
+| Uint8Array#new(16000) | 87,686 ops/sec | ±5.68% | 45 | ✓ |
+| | | | |
+| BrowserBuffer#new(16) | 252,031 ops/sec | ±1.61% | 66 | |
+| Uint8Array#new(16) | 8,477,026 ops/sec | ±0.49% | 68 | ✓ |
+| | | | |
+| BrowserBuffer#readDoubleBE | 99,871 ops/sec | ±0.41% | 69 | |
+| DataView#getFloat64 | 285,663 ops/sec | ±0.70% | 68 | ✓ |
+| | | | |
+| BrowserBuffer#readFloatBE | 115,540 ops/sec | ±0.42% | 69 | |
+| DataView#getFloat32 | 288,722 ops/sec | ±0.82% | 68 | ✓ |
+| | | | |
+| BrowserBuffer#readUInt32LE | 633,926 ops/sec | ±1.08% | 67 | ✓ |
+| DataView#getUint32 | 294,808 ops/sec | ±0.79% | 64 | |
+| | | | |
+| BrowserBuffer#slice | 349,425 ops/sec | ±0.46% | 69 | |
+| Uint8Array#subarray | 5,965,819 ops/sec | ±0.60% | 65 | ✓ |
+| | | | |
+| BrowserBuffer#writeFloatBE | 59,980 ops/sec | ±0.41% | 67 | |
+| DataView#setFloat32 | 317,634 ops/sec | ±0.63% | 68 | ✓ |
+
+### Safari 8
+
+| Method | Operations | Accuracy | Sampled | Fastest |
+|:-------|:-----------|:---------|:--------|:-------:|
+| BrowserBuffer#bracket-notation | 10,279,729 ops/sec | ±2.25% | 56 | ✓ |
+| Uint8Array#bracket-notation | 10,030,767 ops/sec | ±2.23% | 59 | |
+| | | | |
+| BrowserBuffer#concat | 144,138 ops/sec | ±1.38% | 65 | |
+| Uint8Array#concat | 4,950,764 ops/sec | ±1.70% | 63 | ✓ |
+| | | | |
+| BrowserBuffer#copy(16000) | 1,058,548 ops/sec | ±1.51% | 64 | |
+| Uint8Array#copy(16000) | 1,409,666 ops/sec | ±1.17% | 65 | ✓ |
+| | | | |
+| BrowserBuffer#copy(16) | 6,282,529 ops/sec | ±1.88% | 58 | |
+| Uint8Array#copy(16) | 11,907,128 ops/sec | ±2.87% | 58 | ✓ |
+| | | | |
+| BrowserBuffer#new(16000) | 101,663 ops/sec | ±3.89% | 57 | |
+| Uint8Array#new(16000) | 22,050,818 ops/sec | ±6.51% | 46 | ✓ |
+| | | | |
+| BrowserBuffer#new(16) | 176,072 ops/sec | ±2.13% | 64 | |
+| Uint8Array#new(16) | 24,385,731 ops/sec | ±5.01% | 51 | ✓ |
+| | | | |
+| BrowserBuffer#readDoubleBE | 41,341 ops/sec | ±1.06% | 67 | |
+| DataView#getFloat64 | 322,280 ops/sec | ±0.84% | 68 | ✓ |
+| | | | |
+| BrowserBuffer#readFloatBE | 46,141 ops/sec | ±1.06% | 65 | |
+| DataView#getFloat32 | 337,025 ops/sec | ±0.43% | 69 | ✓ |
+| | | | |
+| BrowserBuffer#readUInt32LE | 151,551 ops/sec | ±1.02% | 66 | |
+| DataView#getUint32 | 308,278 ops/sec | ±0.94% | 67 | ✓ |
+| | | | |
+| BrowserBuffer#slice | 197,365 ops/sec | ±0.95% | 66 | |
+| Uint8Array#subarray | 9,558,024 ops/sec | ±3.08% | 58 | ✓ |
+| | | | |
+| BrowserBuffer#writeFloatBE | 17,518 ops/sec | ±1.03% | 63 | |
+| DataView#setFloat32 | 319,751 ops/sec | ±0.48% | 68 | ✓ |
+
+
+### Node 0.11.14
+
+| Method | Operations | Accuracy | Sampled | Fastest |
+|:-------|:-----------|:---------|:--------|:-------:|
+| BrowserBuffer#bracket-notation | 10,489,828 ops/sec | ±3.25% | 90 | |
+| Uint8Array#bracket-notation | 10,534,884 ops/sec | ±0.81% | 92 | ✓ |
+| NodeBuffer#bracket-notation | 10,389,910 ops/sec | ±0.97% | 87 | |
+| | | | |
+| BrowserBuffer#concat | 487,830 ops/sec | ±2.58% | 88 | |
+| Uint8Array#concat | 1,814,327 ops/sec | ±1.28% | 88 | ✓ |
+| NodeBuffer#concat | 1,636,523 ops/sec | ±1.88% | 73 | |
+| | | | |
+| BrowserBuffer#copy(16000) | 1,073,665 ops/sec | ±0.77% | 90 | |
+| Uint8Array#copy(16000) | 1,348,517 ops/sec | ±0.84% | 89 | ✓ |
+| NodeBuffer#copy(16000) | 1,289,533 ops/sec | ±0.82% | 93 | |
+| | | | |
+| BrowserBuffer#copy(16) | 12,782,706 ops/sec | ±0.74% | 85 | |
+| Uint8Array#copy(16) | 14,180,427 ops/sec | ±0.93% | 92 | ✓ |
+| NodeBuffer#copy(16) | 11,083,134 ops/sec | ±1.06% | 89 | |
+| | | | |
+| BrowserBuffer#new(16000) | 141,678 ops/sec | ±3.30% | 67 | |
+| Uint8Array#new(16000) | 161,491 ops/sec | ±2.96% | 60 | |
+| NodeBuffer#new(16000) | 292,699 ops/sec | ±3.20% | 55 | ✓ |
+| | | | |
+| BrowserBuffer#new(16) | 1,655,466 ops/sec | ±2.41% | 82 | |
+| Uint8Array#new(16) | 14,399,926 ops/sec | ±0.91% | 94 | ✓ |
+| NodeBuffer#new(16) | 3,894,696 ops/sec | ±0.88% | 92 | |
+| | | | |
+| BrowserBuffer#readDoubleBE | 109,582 ops/sec | ±0.75% | 93 | ✓ |
+| DataView#getFloat64 | 91,235 ops/sec | ±0.81% | 90 | |
+| NodeBuffer#readDoubleBE | 88,593 ops/sec | ±0.96% | 81 | |
+| | | | |
+| BrowserBuffer#readFloatBE | 139,854 ops/sec | ±1.03% | 85 | ✓ |
+| DataView#getFloat32 | 98,744 ops/sec | ±0.80% | 89 | |
+| NodeBuffer#readFloatBE | 92,769 ops/sec | ±0.94% | 93 | |
+| | | | |
+| BrowserBuffer#readUInt32LE | 710,861 ops/sec | ±0.82% | 92 | |
+| DataView#getUint32 | 117,893 ops/sec | ±0.84% | 91 | |
+| NodeBuffer#readUInt32LE | 851,412 ops/sec | ±0.72% | 93 | ✓ |
+| | | | |
+| BrowserBuffer#slice | 1,673,877 ops/sec | ±0.73% | 94 | |
+| Uint8Array#subarray | 6,919,243 ops/sec | ±0.67% | 90 | ✓ |
+| NodeBuffer#slice | 4,617,604 ops/sec | ±0.79% | 93 | |
+| | | | |
+| BrowserBuffer#writeFloatBE | 66,011 ops/sec | ±0.75% | 93 | |
+| DataView#setFloat32 | 127,760 ops/sec | ±0.72% | 93 | ✓ |
+| NodeBuffer#writeFloatBE | 103,352 ops/sec | ±0.83% | 93 | |
+
+### iojs 1.8.1
+
+| Method | Operations | Accuracy | Sampled | Fastest |
+|:-------|:-----------|:---------|:--------|:-------:|
+| BrowserBuffer#bracket-notation | 10,990,488 ops/sec | ±1.11% | 91 | |
+| Uint8Array#bracket-notation | 11,268,757 ops/sec | ±0.65% | 97 | |
+| NodeBuffer#bracket-notation | 11,353,260 ops/sec | ±0.83% | 94 | ✓ |
+| | | | |
+| BrowserBuffer#concat | 378,954 ops/sec | ±0.74% | 94 | |
+| Uint8Array#concat | 1,358,288 ops/sec | ±0.97% | 87 | |
+| NodeBuffer#concat | 1,934,050 ops/sec | ±1.11% | 78 | ✓ |
+| | | | |
+| BrowserBuffer#copy(16000) | 894,538 ops/sec | ±0.56% | 84 | |
+| Uint8Array#copy(16000) | 1,442,656 ops/sec | ±0.71% | 96 | |
+| NodeBuffer#copy(16000) | 1,457,898 ops/sec | ±0.53% | 92 | ✓ |
+| | | | |
+| BrowserBuffer#copy(16) | 12,870,457 ops/sec | ±0.67% | 95 | |
+| Uint8Array#copy(16) | 16,643,989 ops/sec | ±0.61% | 93 | ✓ |
+| NodeBuffer#copy(16) | 14,885,848 ops/sec | ±0.74% | 94 | |
+| | | | |
+| BrowserBuffer#new(16000) | 109,264 ops/sec | ±4.21% | 63 | |
+| Uint8Array#new(16000) | 138,916 ops/sec | ±1.87% | 61 | |
+| NodeBuffer#new(16000) | 281,449 ops/sec | ±3.58% | 51 | ✓ |
+| | | | |
+| BrowserBuffer#new(16) | 1,362,935 ops/sec | ±0.56% | 99 | |
+| Uint8Array#new(16) | 6,193,090 ops/sec | ±0.64% | 95 | ✓ |
+| NodeBuffer#new(16) | 4,745,425 ops/sec | ±1.56% | 90 | |
+| | | | |
+| BrowserBuffer#readDoubleBE | 118,127 ops/sec | ±0.59% | 93 | ✓ |
+| DataView#getFloat64 | 107,332 ops/sec | ±0.65% | 91 | |
+| NodeBuffer#readDoubleBE | 116,274 ops/sec | ±0.94% | 95 | |
+| | | | |
+| BrowserBuffer#readFloatBE | 150,326 ops/sec | ±0.58% | 95 | ✓ |
+| DataView#getFloat32 | 110,541 ops/sec | ±0.57% | 98 | |
+| NodeBuffer#readFloatBE | 121,599 ops/sec | ±0.60% | 87 | |
+| | | | |
+| BrowserBuffer#readUInt32LE | 814,147 ops/sec | ±0.62% | 93 | |
+| DataView#getUint32 | 137,592 ops/sec | ±0.64% | 90 | |
+| NodeBuffer#readUInt32LE | 931,650 ops/sec | ±0.71% | 96 | ✓ |
+| | | | |
+| BrowserBuffer#slice | 878,590 ops/sec | ±0.68% | 93 | |
+| Uint8Array#subarray | 2,843,308 ops/sec | ±1.02% | 90 | |
+| NodeBuffer#slice | 4,998,316 ops/sec | ±0.68% | 90 | ✓ |
+| | | | |
+| BrowserBuffer#writeFloatBE | 65,927 ops/sec | ±0.74% | 93 | |
+| DataView#setFloat32 | 139,823 ops/sec | ±0.97% | 89 | ✓ |
+| NodeBuffer#writeFloatBE | 135,763 ops/sec | ±0.65% | 96 | |
+| | | | |
+
+## Testing the project
+
+First, install the project:
+
+    npm install
+
+Then, to run tests in Node.js, run:
+
+    npm run test-node
+
+To test locally in a browser, you can run:
+
+    npm run test-browser-es5-local # For ES5 browsers that don't support ES6
+    npm run test-browser-es6-local # For ES6 compliant browsers
+
+This will print out a URL that you can then open in a browser to run the tests, using [airtap](https://www.npmjs.com/package/airtap).
+
+To run automated browser tests using Saucelabs, ensure that your `SAUCE_USERNAME` and `SAUCE_ACCESS_KEY` environment variables are set, then run:
+
+    npm test
+
+This is what's run in Travis, to check against various browsers. The list of browsers is kept in the `bin/airtap-es5.yml` and `bin/airtap-es6.yml` files.
+
+## JavaScript Standard Style
+
+This module uses [JavaScript Standard Style](https://github.com/feross/standard).
+
+[![JavaScript Style Guide](https://cdn.rawgit.com/feross/standard/master/badge.svg)](https://github.com/feross/standard)
+
+To test that the code conforms to the style, `npm install` and run:
+
+    ./node_modules/.bin/standard
+
+## credit
+
+This was originally forked from [buffer-browserify](https://github.com/toots/buffer-browserify).
+
+## Security Policies and Procedures
+
+The `buffer` team and community take all security bugs in `buffer` seriously. Please see our [security policies and procedures](https://github.com/feross/security) document to learn how to report issues.
+
+## license
+
+MIT. Copyright (C) [Feross Aboukhadijeh](http://feross.org), and other contributors. Originally forked from an MIT-licensed module by Romain Beauxis.
diff --git a/server/node_modules/buffer/index.d.ts b/server/node_modules/buffer/index.d.ts
new file mode 100644
index 0000000..5d1a804
--- /dev/null
+++ b/server/node_modules/buffer/index.d.ts
@@ -0,0 +1,186 @@
+export class Buffer extends Uint8Array {
+    length: number
+    write(string: string, offset?: number, length?: number, encoding?: string): number;
+    toString(encoding?: string, start?: number, end?: number): string;
+    toJSON(): { type: 'Buffer', data: any[] };
+    equals(otherBuffer: Buffer): boolean;
+    compare(otherBuffer: Buffer, targetStart?: number, targetEnd?: number, sourceStart?: number, sourceEnd?: number): number;
+    copy(targetBuffer: Buffer, targetStart?: number, sourceStart?: number, sourceEnd?: number): number;
+    slice(start?: number, end?: number): Buffer;
+    writeUIntLE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeUIntBE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeIntLE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeIntBE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    readUIntLE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readUIntBE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readIntLE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readIntBE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readUInt8(offset: number, noAssert?: boolean): number;
+    readUInt16LE(offset: number, noAssert?: boolean): number;
+    readUInt16BE(offset: number, noAssert?: boolean): number;
+    readUInt32LE(offset: number, noAssert?: boolean): number;
+    readUInt32BE(offset: number, noAssert?: boolean): number;
+    readInt8(offset: number, noAssert?: boolean): number;
+    readInt16LE(offset: number, noAssert?: boolean): number;
+    readInt16BE(offset: number, noAssert?: boolean): number;
+    readInt32LE(offset: number, noAssert?: boolean): number;
+    readInt32BE(offset: number, noAssert?: boolean): number;
+    readFloatLE(offset: number, noAssert?: boolean): number;
+    readFloatBE(offset: number, noAssert?: boolean): number;
+    readDoubleLE(offset: number, noAssert?: boolean): number;
+    readDoubleBE(offset: number, noAssert?: boolean): number;
+    reverse(): this;
+    swap16(): Buffer;
+    swap32(): Buffer;
+    swap64(): Buffer;
+    writeUInt8(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt16LE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt16BE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt32LE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt32BE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt8(value: number, offset: number, noAssert?: boolean): number;
+    writeInt16LE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt16BE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt32LE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt32BE(value: number, offset: number, noAssert?: boolean): number;
+    writeFloatLE(value: number, offset: number, noAssert?: boolean): number;
+    writeFloatBE(value: number, offset: number, noAssert?: boolean): number;
+    writeDoubleLE(value: number, offset: number, noAssert?: boolean): number;
+    writeDoubleBE(value: number, offset: number, noAssert?: boolean): number;
+    fill(value: any, offset?: number, end?: number): this;
+    indexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
+    lastIndexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
+    includes(value: string | number | Buffer, byteOffset?: number, encoding?: string): boolean;
+
+    /**
+     * Allocates a new buffer containing the given {str}.
+     *
+     * @param str String to store in buffer.
+     * @param encoding encoding to use, optional.  Default is 'utf8'
+     */
+    constructor (str: string, encoding?: string);
+    /**
+     * Allocates a new buffer of {size} octets.
+     *
+     * @param size count of octets to allocate.
+     */
+    constructor (size: number);
+    /**
+     * Allocates a new buffer containing the given {array} of octets.
+     *
+     * @param array The octets to store.
+     */
+    constructor (array: Uint8Array);
+    /**
+     * Produces a Buffer backed by the same allocated memory as
+     * the given {ArrayBuffer}.
+     *
+     *
+     * @param arrayBuffer The ArrayBuffer with which to share memory.
+     */
+    constructor (arrayBuffer: ArrayBuffer);
+    /**
+     * Allocates a new buffer containing the given {array} of octets.
+     *
+     * @param array The octets to store.
+     */
+    constructor (array: any[]);
+    /**
+     * Copies the passed {buffer} data onto a new {Buffer} instance.
+     *
+     * @param buffer The buffer to copy.
+     */
+    constructor (buffer: Buffer);
+    prototype: Buffer;
+    /**
+     * Allocates a new Buffer using an {array} of octets.
+     *
+     * @param array
+     */
+    static from(array: any[]): Buffer;
+    /**
+     * When passed a reference to the .buffer property of a TypedArray instance,
+     * the newly created Buffer will share the same allocated memory as the TypedArray.
+     * The optional {byteOffset} and {length} arguments specify a memory range
+     * within the {arrayBuffer} that will be shared by the Buffer.
+     *
+     * @param arrayBuffer The .buffer property of a TypedArray or a new ArrayBuffer()
+     * @param byteOffset
+     * @param length
+     */
+    static from(arrayBuffer: ArrayBuffer, byteOffset?: number, length?: number): Buffer;
+    /**
+     * Copies the passed {buffer} data onto a new Buffer instance.
+     *
+     * @param buffer
+     */
+    static from(buffer: Buffer | Uint8Array): Buffer;
+    /**
+     * Creates a new Buffer containing the given JavaScript string {str}.
+     * If provided, the {encoding} parameter identifies the character encoding.
+     * If not provided, {encoding} defaults to 'utf8'.
+     *
+     * @param str
+     */
+    static from(str: string, encoding?: string): Buffer;
+    /**
+     * Returns true if {obj} is a Buffer
+     *
+     * @param obj object to test.
+     */
+    static isBuffer(obj: any): obj is Buffer;
+    /**
+     * Returns true if {encoding} is a valid encoding argument.
+     * Valid string encodings in Node 0.12: 'ascii'|'utf8'|'utf16le'|'ucs2'(alias of 'utf16le')|'base64'|'binary'(deprecated)|'hex'
+     *
+     * @param encoding string to test.
+     */
+    static isEncoding(encoding: string): boolean;
+    /**
+     * Gives the actual byte length of a string. encoding defaults to 'utf8'.
+     * This is not the same as String.prototype.length since that returns the number of characters in a string.
+     *
+     * @param string string to test.
+     * @param encoding encoding used to evaluate (defaults to 'utf8')
+     */
+    static byteLength(string: string, encoding?: string): number;
+    /**
+     * Returns a buffer which is the result of concatenating all the buffers in the list together.
+     *
+     * If the list has no items, or if the totalLength is 0, then it returns a zero-length buffer.
+     * If the list has exactly one item, then the first item of the list is returned.
+     * If the list has more than one item, then a new Buffer is created.
+     *
+     * @param list An array of Buffer objects to concatenate
+     * @param totalLength Total length of the buffers when concatenated.
+     *   If totalLength is not provided, it is read from the buffers in the list. However, this adds an additional loop to the function, so it is faster to provide the length explicitly.
+     */
+    static concat(list: Buffer[], totalLength?: number): Buffer;
+    /**
+     * The same as buf1.compare(buf2).
+     */
+    static compare(buf1: Buffer, buf2: Buffer): number;
+    /**
+     * Allocates a new buffer of {size} octets.
+     *
+     * @param size count of octets to allocate.
+     * @param fill if specified, buffer will be initialized by calling buf.fill(fill).
+     *    If parameter is omitted, buffer will be filled with zeros.
+     * @param encoding encoding used for call to buf.fill while initializing
+     */
+    static alloc(size: number, fill?: string | Buffer | number, encoding?: string): Buffer;
+    /**
+     * Allocates a new buffer of {size} octets, leaving memory not initialized, so the contents
+     * of the newly created Buffer are unknown and may contain sensitive data.
+     *
+     * @param size count of octets to allocate
+     */
+    static allocUnsafe(size: number): Buffer;
+    /**
+     * Allocates a new non-pooled buffer of {size} octets, leaving memory not initialized, so the contents
+     * of the newly created Buffer are unknown and may contain sensitive data.
+     *
+     * @param size count of octets to allocate
+     */
+    static allocUnsafeSlow(size: number): Buffer;
+}
diff --git a/server/node_modules/buffer/index.js b/server/node_modules/buffer/index.js
new file mode 100644
index 0000000..609cf31
--- /dev/null
+++ b/server/node_modules/buffer/index.js
@@ -0,0 +1,1817 @@
+/*!
+ * The buffer module from node.js, for the browser.
+ *
+ * @author   Feross Aboukhadijeh <https://feross.org>
+ * @license  MIT
+ */
+/* eslint-disable no-proto */
+
+'use strict'
+
+var base64 = require('base64-js')
+var ieee754 = require('ieee754')
+var customInspectSymbol =
+  (typeof Symbol === 'function' && typeof Symbol['for'] === 'function') // eslint-disable-line dot-notation
+    ? Symbol['for']('nodejs.util.inspect.custom') // eslint-disable-line dot-notation
+    : null
+
+exports.Buffer = Buffer
+exports.SlowBuffer = SlowBuffer
+exports.INSPECT_MAX_BYTES = 50
+
+var K_MAX_LENGTH = 0x7fffffff
+exports.kMaxLength = K_MAX_LENGTH
+
+/**
+ * If `Buffer.TYPED_ARRAY_SUPPORT`:
+ *   === true    Use Uint8Array implementation (fastest)
+ *   === false   Print warning and recommend using `buffer` v4.x which has an Object
+ *               implementation (most compatible, even IE6)
+ *
+ * Browsers that support typed arrays are IE 10+, Firefox 4+, Chrome 7+, Safari 5.1+,
+ * Opera 11.6+, iOS 4.2+.
+ *
+ * We report that the browser does not support typed arrays if the are not subclassable
+ * using __proto__. Firefox 4-29 lacks support for adding new properties to `Uint8Array`
+ * (See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438). IE 10 lacks support
+ * for __proto__ and has a buggy typed array implementation.
+ */
+Buffer.TYPED_ARRAY_SUPPORT = typedArraySupport()
+
+if (!Buffer.TYPED_ARRAY_SUPPORT && typeof console !== 'undefined' &&
+    typeof console.error === 'function') {
+  console.error(
+    'This browser lacks typed array (Uint8Array) support which is required by ' +
+    '`buffer` v5.x. Use `buffer` v4.x if you require old browser support.'
+  )
+}
+
+function typedArraySupport () {
+  // Can typed array instances can be augmented?
+  try {
+    var arr = new Uint8Array(1)
+    var proto = { foo: function () { return 42 } }
+    Object.setPrototypeOf(proto, Uint8Array.prototype)
+    Object.setPrototypeOf(arr, proto)
+    return arr.foo() === 42
+  } catch (e) {
+    return false
+  }
+}
+
+Object.defineProperty(Buffer.prototype, 'parent', {
+  enumerable: true,
+  get: function () {
+    if (!Buffer.isBuffer(this)) return undefined
+    return this.buffer
+  }
+})
+
+Object.defineProperty(Buffer.prototype, 'offset', {
+  enumerable: true,
+  get: function () {
+    if (!Buffer.isBuffer(this)) return undefined
+    return this.byteOffset
+  }
+})
+
+function createBuffer (length) {
+  if (length > K_MAX_LENGTH) {
+    throw new RangeError('The value "' + length + '" is invalid for option "size"')
+  }
+  // Return an augmented `Uint8Array` instance
+  var buf = new Uint8Array(length)
+  Object.setPrototypeOf(buf, Buffer.prototype)
+  return buf
+}
+
+/**
+ * The Buffer constructor returns instances of `Uint8Array` that have their
+ * prototype changed to `Buffer.prototype`. Furthermore, `Buffer` is a subclass of
+ * `Uint8Array`, so the returned instances will have all the node `Buffer` methods
+ * and the `Uint8Array` methods. Square bracket notation works as expected -- it
+ * returns a single octet.
+ *
+ * The `Uint8Array` prototype remains unmodified.
+ */
+
+function Buffer (arg, encodingOrOffset, length) {
+  // Common case.
+  if (typeof arg === 'number') {
+    if (typeof encodingOrOffset === 'string') {
+      throw new TypeError(
+        'The "string" argument must be of type string. Received type number'
+      )
+    }
+    return allocUnsafe(arg)
+  }
+  return from(arg, encodingOrOffset, length)
+}
+
+Buffer.poolSize = 8192 // not used by this implementation
+
+function from (value, encodingOrOffset, length) {
+  if (typeof value === 'string') {
+    return fromString(value, encodingOrOffset)
+  }
+
+  if (ArrayBuffer.isView(value)) {
+    return fromArrayView(value)
+  }
+
+  if (value == null) {
+    throw new TypeError(
+      'The first argument must be one of type string, Buffer, ArrayBuffer, Array, ' +
+      'or Array-like Object. Received type ' + (typeof value)
+    )
+  }
+
+  if (isInstance(value, ArrayBuffer) ||
+      (value && isInstance(value.buffer, ArrayBuffer))) {
+    return fromArrayBuffer(value, encodingOrOffset, length)
+  }
+
+  if (typeof SharedArrayBuffer !== 'undefined' &&
+      (isInstance(value, SharedArrayBuffer) ||
+      (value && isInstance(value.buffer, SharedArrayBuffer)))) {
+    return fromArrayBuffer(value, encodingOrOffset, length)
+  }
+
+  if (typeof value === 'number') {
+    throw new TypeError(
+      'The "value" argument must not be of type number. Received type number'
+    )
+  }
+
+  var valueOf = value.valueOf && value.valueOf()
+  if (valueOf != null && valueOf !== value) {
+    return Buffer.from(valueOf, encodingOrOffset, length)
+  }
+
+  var b = fromObject(value)
+  if (b) return b
+
+  if (typeof Symbol !== 'undefined' && Symbol.toPrimitive != null &&
+      typeof value[Symbol.toPrimitive] === 'function') {
+    return Buffer.from(
+      value[Symbol.toPrimitive]('string'), encodingOrOffset, length
+    )
+  }
+
+  throw new TypeError(
+    'The first argument must be one of type string, Buffer, ArrayBuffer, Array, ' +
+    'or Array-like Object. Received type ' + (typeof value)
+  )
+}
+
+/**
+ * Functionally equivalent to Buffer(arg, encoding) but throws a TypeError
+ * if value is a number.
+ * Buffer.from(str[, encoding])
+ * Buffer.from(array)
+ * Buffer.from(buffer)
+ * Buffer.from(arrayBuffer[, byteOffset[, length]])
+ **/
+Buffer.from = function (value, encodingOrOffset, length) {
+  return from(value, encodingOrOffset, length)
+}
+
+// Note: Change prototype *after* Buffer.from is defined to workaround Chrome bug:
+// https://github.com/feross/buffer/pull/148
+Object.setPrototypeOf(Buffer.prototype, Uint8Array.prototype)
+Object.setPrototypeOf(Buffer, Uint8Array)
+
+function assertSize (size) {
+  if (typeof size !== 'number') {
+    throw new TypeError('"size" argument must be of type number')
+  } else if (size < 0) {
+    throw new RangeError('The value "' + size + '" is invalid for option "size"')
+  }
+}
+
+function alloc (size, fill, encoding) {
+  assertSize(size)
+  if (size <= 0) {
+    return createBuffer(size)
+  }
+  if (fill !== undefined) {
+    // Only pay attention to encoding if it's a string. This
+    // prevents accidentally sending in a number that would
+    // be interpreted as a start offset.
+    return typeof encoding === 'string'
+      ? createBuffer(size).fill(fill, encoding)
+      : createBuffer(size).fill(fill)
+  }
+  return createBuffer(size)
+}
+
+/**
+ * Creates a new filled Buffer instance.
+ * alloc(size[, fill[, encoding]])
+ **/
+Buffer.alloc = function (size, fill, encoding) {
+  return alloc(size, fill, encoding)
+}
+
+function allocUnsafe (size) {
+  assertSize(size)
+  return createBuffer(size < 0 ? 0 : checked(size) | 0)
+}
+
+/**
+ * Equivalent to Buffer(num), by default creates a non-zero-filled Buffer instance.
+ * */
+Buffer.allocUnsafe = function (size) {
+  return allocUnsafe(size)
+}
+/**
+ * Equivalent to SlowBuffer(num), by default creates a non-zero-filled Buffer instance.
+ */
+Buffer.allocUnsafeSlow = function (size) {
+  return allocUnsafe(size)
+}
+
+function fromString (string, encoding) {
+  if (typeof encoding !== 'string' || encoding === '') {
+    encoding = 'utf8'
+  }
+
+  if (!Buffer.isEncoding(encoding)) {
+    throw new TypeError('Unknown encoding: ' + encoding)
+  }
+
+  var length = byteLength(string, encoding) | 0
+  var buf = createBuffer(length)
+
+  var actual = buf.write(string, encoding)
+
+  if (actual !== length) {
+    // Writing a hex string, for example, that contains invalid characters will
+    // cause everything after the first invalid character to be ignored. (e.g.
+    // 'abxxcd' will be treated as 'ab')
+    buf = buf.slice(0, actual)
+  }
+
+  return buf
+}
+
+function fromArrayLike (array) {
+  var length = array.length < 0 ? 0 : checked(array.length) | 0
+  var buf = createBuffer(length)
+  for (var i = 0; i < length; i += 1) {
+    buf[i] = array[i] & 255
+  }
+  return buf
+}
+
+function fromArrayView (arrayView) {
+  if (isInstance(arrayView, Uint8Array)) {
+    var copy = new Uint8Array(arrayView)
+    return fromArrayBuffer(copy.buffer, copy.byteOffset, copy.byteLength)
+  }
+  return fromArrayLike(arrayView)
+}
+
+function fromArrayBuffer (array, byteOffset, length) {
+  if (byteOffset < 0 || array.byteLength < byteOffset) {
+    throw new RangeError('"offset" is outside of buffer bounds')
+  }
+
+  if (array.byteLength < byteOffset + (length || 0)) {
+    throw new RangeError('"length" is outside of buffer bounds')
+  }
+
+  var buf
+  if (byteOffset === undefined && length === undefined) {
+    buf = new Uint8Array(array)
+  } else if (length === undefined) {
+    buf = new Uint8Array(array, byteOffset)
+  } else {
+    buf = new Uint8Array(array, byteOffset, length)
+  }
+
+  // Return an augmented `Uint8Array` instance
+  Object.setPrototypeOf(buf, Buffer.prototype)
+
+  return buf
+}
+
+function fromObject (obj) {
+  if (Buffer.isBuffer(obj)) {
+    var len = checked(obj.length) | 0
+    var buf = createBuffer(len)
+
+    if (buf.length === 0) {
+      return buf
+    }
+
+    obj.copy(buf, 0, 0, len)
+    return buf
+  }
+
+  if (obj.length !== undefined) {
+    if (typeof obj.length !== 'number' || numberIsNaN(obj.length)) {
+      return createBuffer(0)
+    }
+    return fromArrayLike(obj)
+  }
+
+  if (obj.type === 'Buffer' && Array.isArray(obj.data)) {
+    return fromArrayLike(obj.data)
+  }
+}
+
+function checked (length) {
+  // Note: cannot use `length < K_MAX_LENGTH` here because that fails when
+  // length is NaN (which is otherwise coerced to zero.)
+  if (length >= K_MAX_LENGTH) {
+    throw new RangeError('Attempt to allocate Buffer larger than maximum ' +
+                         'size: 0x' + K_MAX_LENGTH.toString(16) + ' bytes')
+  }
+  return length | 0
+}
+
+function SlowBuffer (length) {
+  if (+length != length) { // eslint-disable-line eqeqeq
+    length = 0
+  }
+  return Buffer.alloc(+length)
+}
+
+Buffer.isBuffer = function isBuffer (b) {
+  return b != null && b._isBuffer === true &&
+    b !== Buffer.prototype // so Buffer.isBuffer(Buffer.prototype) will be false
+}
+
+Buffer.compare = function compare (a, b) {
+  if (isInstance(a, Uint8Array)) a = Buffer.from(a, a.offset, a.byteLength)
+  if (isInstance(b, Uint8Array)) b = Buffer.from(b, b.offset, b.byteLength)
+  if (!Buffer.isBuffer(a) || !Buffer.isBuffer(b)) {
+    throw new TypeError(
+      'The "buf1", "buf2" arguments must be one of type Buffer or Uint8Array'
+    )
+  }
+
+  if (a === b) return 0
+
+  var x = a.length
+  var y = b.length
+
+  for (var i = 0, len = Math.min(x, y); i < len; ++i) {
+    if (a[i] !== b[i]) {
+      x = a[i]
+      y = b[i]
+      break
+    }
+  }
+
+  if (x < y) return -1
+  if (y < x) return 1
+  return 0
+}
+
+Buffer.isEncoding = function isEncoding (encoding) {
+  switch (String(encoding).toLowerCase()) {
+    case 'hex':
+    case 'utf8':
+    case 'utf-8':
+    case 'ascii':
+    case 'latin1':
+    case 'binary':
+    case 'base64':
+    case 'ucs2':
+    case 'ucs-2':
+    case 'utf16le':
+    case 'utf-16le':
+      return true
+    default:
+      return false
+  }
+}
+
+Buffer.concat = function concat (list, length) {
+  if (!Array.isArray(list)) {
+    throw new TypeError('"list" argument must be an Array of Buffers')
+  }
+
+  if (list.length === 0) {
+    return Buffer.alloc(0)
+  }
+
+  var i
+  if (length === undefined) {
+    length = 0
+    for (i = 0; i < list.length; ++i) {
+      length += list[i].length
+    }
+  }
+
+  var buffer = Buffer.allocUnsafe(length)
+  var pos = 0
+  for (i = 0; i < list.length; ++i) {
+    var buf = list[i]
+    if (isInstance(buf, Uint8Array)) {
+      if (pos + buf.length > buffer.length) {
+        Buffer.from(buf).copy(buffer, pos)
+      } else {
+        Uint8Array.prototype.set.call(
+          buffer,
+          buf,
+          pos
+        )
+      }
+    } else if (!Buffer.isBuffer(buf)) {
+      throw new TypeError('"list" argument must be an Array of Buffers')
+    } else {
+      buf.copy(buffer, pos)
+    }
+    pos += buf.length
+  }
+  return buffer
+}
+
+function byteLength (string, encoding) {
+  if (Buffer.isBuffer(string)) {
+    return string.length
+  }
+  if (ArrayBuffer.isView(string) || isInstance(string, ArrayBuffer)) {
+    return string.byteLength
+  }
+  if (typeof string !== 'string') {
+    throw new TypeError(
+      'The "string" argument must be one of type string, Buffer, or ArrayBuffer. ' +
+      'Received type ' + typeof string
+    )
+  }
+
+  var len = string.length
+  var mustMatch = (arguments.length > 2 && arguments[2] === true)
+  if (!mustMatch && len === 0) return 0
+
+  // Use a for loop to avoid recursion
+  var loweredCase = false
+  for (;;) {
+    switch (encoding) {
+      case 'ascii':
+      case 'latin1':
+      case 'binary':
+        return len
+      case 'utf8':
+      case 'utf-8':
+        return utf8ToBytes(string).length
+      case 'ucs2':
+      case 'ucs-2':
+      case 'utf16le':
+      case 'utf-16le':
+        return len * 2
+      case 'hex':
+        return len >>> 1
+      case 'base64':
+        return base64ToBytes(string).length
+      default:
+        if (loweredCase) {
+          return mustMatch ? -1 : utf8ToBytes(string).length // assume utf8
+        }
+        encoding = ('' + encoding).toLowerCase()
+        loweredCase = true
+    }
+  }
+}
+Buffer.byteLength = byteLength
+
+function slowToString (encoding, start, end) {
+  var loweredCase = false
+
+  // No need to verify that "this.length <= MAX_UINT32" since it's a read-only
+  // property of a typed array.
+
+  // This behaves neither like String nor Uint8Array in that we set start/end
+  // to their upper/lower bounds if the value passed is out of range.
+  // undefined is handled specially as per ECMA-262 6th Edition,
+  // Section 13.3.3.7 Runtime Semantics: KeyedBindingInitialization.
+  if (start === undefined || start < 0) {
+    start = 0
+  }
+  // Return early if start > this.length. Done here to prevent potential uint32
+  // coercion fail below.
+  if (start > this.length) {
+    return ''
+  }
+
+  if (end === undefined || end > this.length) {
+    end = this.length
+  }
+
+  if (end <= 0) {
+    return ''
+  }
+
+  // Force coercion to uint32. This will also coerce falsey/NaN values to 0.
+  end >>>= 0
+  start >>>= 0
+
+  if (end <= start) {
+    return ''
+  }
+
+  if (!encoding) encoding = 'utf8'
+
+  while (true) {
+    switch (encoding) {
+      case 'hex':
+        return hexSlice(this, start, end)
+
+      case 'utf8':
+      case 'utf-8':
+        return utf8Slice(this, start, end)
+
+      case 'ascii':
+        return asciiSlice(this, start, end)
+
+      case 'latin1':
+      case 'binary':
+        return latin1Slice(this, start, end)
+
+      case 'base64':
+        return base64Slice(this, start, end)
+
+      case 'ucs2':
+      case 'ucs-2':
+      case 'utf16le':
+      case 'utf-16le':
+        return utf16leSlice(this, start, end)
+
+      default:
+        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding)
+        encoding = (encoding + '').toLowerCase()
+        loweredCase = true
+    }
+  }
+}
+
+// This property is used by `Buffer.isBuffer` (and the `is-buffer` npm package)
+// to detect a Buffer instance. It's not possible to use `instanceof Buffer`
+// reliably in a browserify context because there could be multiple different
+// copies of the 'buffer' package in use. This method works even for Buffer
+// instances that were created from another copy of the `buffer` package.
+// See: https://github.com/feross/buffer/issues/154
+Buffer.prototype._isBuffer = true
+
+function swap (b, n, m) {
+  var i = b[n]
+  b[n] = b[m]
+  b[m] = i
+}
+
+Buffer.prototype.swap16 = function swap16 () {
+  var len = this.length
+  if (len % 2 !== 0) {
+    throw new RangeError('Buffer size must be a multiple of 16-bits')
+  }
+  for (var i = 0; i < len; i += 2) {
+    swap(this, i, i + 1)
+  }
+  return this
+}
+
+Buffer.prototype.swap32 = function swap32 () {
+  var len = this.length
+  if (len % 4 !== 0) {
+    throw new RangeError('Buffer size must be a multiple of 32-bits')
+  }
+  for (var i = 0; i < len; i += 4) {
+    swap(this, i, i + 3)
+    swap(this, i + 1, i + 2)
+  }
+  return this
+}
+
+Buffer.prototype.swap64 = function swap64 () {
+  var len = this.length
+  if (len % 8 !== 0) {
+    throw new RangeError('Buffer size must be a multiple of 64-bits')
+  }
+  for (var i = 0; i < len; i += 8) {
+    swap(this, i, i + 7)
+    swap(this, i + 1, i + 6)
+    swap(this, i + 2, i + 5)
+    swap(this, i + 3, i + 4)
+  }
+  return this
+}
+
+Buffer.prototype.toString = function toString () {
+  var length = this.length
+  if (length === 0) return ''
+  if (arguments.length === 0) return utf8Slice(this, 0, length)
+  return slowToString.apply(this, arguments)
+}
+
+Buffer.prototype.toLocaleString = Buffer.prototype.toString
+
+Buffer.prototype.equals = function equals (b) {
+  if (!Buffer.isBuffer(b)) throw new TypeError('Argument must be a Buffer')
+  if (this === b) return true
+  return Buffer.compare(this, b) === 0
+}
+
+Buffer.prototype.inspect = function inspect () {
+  var str = ''
+  var max = exports.INSPECT_MAX_BYTES
+  str = this.toString('hex', 0, max).replace(/(.{2})/g, '$1 ').trim()
+  if (this.length > max) str += ' ... '
+  return '<Buffer ' + str + '>'
+}
+if (customInspectSymbol) {
+  Buffer.prototype[customInspectSymbol] = Buffer.prototype.inspect
+}
+
+Buffer.prototype.compare = function compare (target, start, end, thisStart, thisEnd) {
+  if (isInstance(target, Uint8Array)) {
+    target = Buffer.from(target, target.offset, target.byteLength)
+  }
+  if (!Buffer.isBuffer(target)) {
+    throw new TypeError(
+      'The "target" argument must be one of type Buffer or Uint8Array. ' +
+      'Received type ' + (typeof target)
+    )
+  }
+
+  if (start === undefined) {
+    start = 0
+  }
+  if (end === undefined) {
+    end = target ? target.length : 0
+  }
+  if (thisStart === undefined) {
+    thisStart = 0
+  }
+  if (thisEnd === undefined) {
+    thisEnd = this.length
+  }
+
+  if (start < 0 || end > target.length || thisStart < 0 || thisEnd > this.length) {
+    throw new RangeError('out of range index')
+  }
+
+  if (thisStart >= thisEnd && start >= end) {
+    return 0
+  }
+  if (thisStart >= thisEnd) {
+    return -1
+  }
+  if (start >= end) {
+    return 1
+  }
+
+  start >>>= 0
+  end >>>= 0
+  thisStart >>>= 0
+  thisEnd >>>= 0
+
+  if (this === target) return 0
+
+  var x = thisEnd - thisStart
+  var y = end - start
+  var len = Math.min(x, y)
+
+  var thisCopy = this.slice(thisStart, thisEnd)
+  var targetCopy = target.slice(start, end)
+
+  for (var i = 0; i < len; ++i) {
+    if (thisCopy[i] !== targetCopy[i]) {
+      x = thisCopy[i]
+      y = targetCopy[i]
+      break
+    }
+  }
+
+  if (x < y) return -1
+  if (y < x) return 1
+  return 0
+}
+
+// Finds either the first index of `val` in `buffer` at offset >= `byteOffset`,
+// OR the last index of `val` in `buffer` at offset <= `byteOffset`.
+//
+// Arguments:
+// - buffer - a Buffer to search
+// - val - a string, Buffer, or number
+// - byteOffset - an index into `buffer`; will be clamped to an int32
+// - encoding - an optional encoding, relevant is val is a string
+// - dir - true for indexOf, false for lastIndexOf
+function bidirectionalIndexOf (buffer, val, byteOffset, encoding, dir) {
+  // Empty buffer means no match
+  if (buffer.length === 0) return -1
+
+  // Normalize byteOffset
+  if (typeof byteOffset === 'string') {
+    encoding = byteOffset
+    byteOffset = 0
+  } else if (byteOffset > 0x7fffffff) {
+    byteOffset = 0x7fffffff
+  } else if (byteOffset < -0x80000000) {
+    byteOffset = -0x80000000
+  }
+  byteOffset = +byteOffset // Coerce to Number.
+  if (numberIsNaN(byteOffset)) {
+    // byteOffset: it it's undefined, null, NaN, "foo", etc, search whole buffer
+    byteOffset = dir ? 0 : (buffer.length - 1)
+  }
+
+  // Normalize byteOffset: negative offsets start from the end of the buffer
+  if (byteOffset < 0) byteOffset = buffer.length + byteOffset
+  if (byteOffset >= buffer.length) {
+    if (dir) return -1
+    else byteOffset = buffer.length - 1
+  } else if (byteOffset < 0) {
+    if (dir) byteOffset = 0
+    else return -1
+  }
+
+  // Normalize val
+  if (typeof val === 'string') {
+    val = Buffer.from(val, encoding)
+  }
+
+  // Finally, search either indexOf (if dir is true) or lastIndexOf
+  if (Buffer.isBuffer(val)) {
+    // Special case: looking for empty string/buffer always fails
+    if (val.length === 0) {
+      return -1
+    }
+    return arrayIndexOf(buffer, val, byteOffset, encoding, dir)
+  } else if (typeof val === 'number') {
+    val = val & 0xFF // Search for a byte value [0-255]
+    if (typeof Uint8Array.prototype.indexOf === 'function') {
+      if (dir) {
+        return Uint8Array.prototype.indexOf.call(buffer, val, byteOffset)
+      } else {
+        return Uint8Array.prototype.lastIndexOf.call(buffer, val, byteOffset)
+      }
+    }
+    return arrayIndexOf(buffer, [val], byteOffset, encoding, dir)
+  }
+
+  throw new TypeError('val must be string, number or Buffer')
+}
+
+function arrayIndexOf (arr, val, byteOffset, encoding, dir) {
+  var indexSize = 1
+  var arrLength = arr.length
+  var valLength = val.length
+
+  if (encoding !== undefined) {
+    encoding = String(encoding).toLowerCase()
+    if (encoding === 'ucs2' || encoding === 'ucs-2' ||
+        encoding === 'utf16le' || encoding === 'utf-16le') {
+      if (arr.length < 2 || val.length < 2) {
+        return -1
+      }
+      indexSize = 2
+      arrLength /= 2
+      valLength /= 2
+      byteOffset /= 2
+    }
+  }
+
+  function read (buf, i) {
+    if (indexSize === 1) {
+      return buf[i]
+    } else {
+      return buf.readUInt16BE(i * indexSize)
+    }
+  }
+
+  var i
+  if (dir) {
+    var foundIndex = -1
+    for (i = byteOffset; i < arrLength; i++) {
+      if (read(arr, i) === read(val, foundIndex === -1 ? 0 : i - foundIndex)) {
+        if (foundIndex === -1) foundIndex = i
+        if (i - foundIndex + 1 === valLength) return foundIndex * indexSize
+      } else {
+        if (foundIndex !== -1) i -= i - foundIndex
+        foundIndex = -1
+      }
+    }
+  } else {
+    if (byteOffset + valLength > arrLength) byteOffset = arrLength - valLength
+    for (i = byteOffset; i >= 0; i--) {
+      var found = true
+      for (var j = 0; j < valLength; j++) {
+        if (read(arr, i + j) !== read(val, j)) {
+          found = false
+          break
+        }
+      }
+      if (found) return i
+    }
+  }
+
+  return -1
+}
+
+Buffer.prototype.includes = function includes (val, byteOffset, encoding) {
+  return this.indexOf(val, byteOffset, encoding) !== -1
+}
+
+Buffer.prototype.indexOf = function indexOf (val, byteOffset, encoding) {
+  return bidirectionalIndexOf(this, val, byteOffset, encoding, true)
+}
+
+Buffer.prototype.lastIndexOf = function lastIndexOf (val, byteOffset, encoding) {
+  return bidirectionalIndexOf(this, val, byteOffset, encoding, false)
+}
+
+function hexWrite (buf, string, offset, length) {
+  offset = Number(offset) || 0
+  var remaining = buf.length - offset
+  if (!length) {
+    length = remaining
+  } else {
+    length = Number(length)
+    if (length > remaining) {
+      length = remaining
+    }
+  }
+
+  var strLen = string.length
+
+  if (length > strLen / 2) {
+    length = strLen / 2
+  }
+  for (var i = 0; i < length; ++i) {
+    var parsed = parseInt(string.substr(i * 2, 2), 16)
+    if (numberIsNaN(parsed)) return i
+    buf[offset + i] = parsed
+  }
+  return i
+}
+
+function utf8Write (buf, string, offset, length) {
+  return blitBuffer(utf8ToBytes(string, buf.length - offset), buf, offset, length)
+}
+
+function asciiWrite (buf, string, offset, length) {
+  return blitBuffer(asciiToBytes(string), buf, offset, length)
+}
+
+function base64Write (buf, string, offset, length) {
+  return blitBuffer(base64ToBytes(string), buf, offset, length)
+}
+
+function ucs2Write (buf, string, offset, length) {
+  return blitBuffer(utf16leToBytes(string, buf.length - offset), buf, offset, length)
+}
+
+Buffer.prototype.write = function write (string, offset, length, encoding) {
+  // Buffer#write(string)
+  if (offset === undefined) {
+    encoding = 'utf8'
+    length = this.length
+    offset = 0
+  // Buffer#write(string, encoding)
+  } else if (length === undefined && typeof offset === 'string') {
+    encoding = offset
+    length = this.length
+    offset = 0
+  // Buffer#write(string, offset[, length][, encoding])
+  } else if (isFinite(offset)) {
+    offset = offset >>> 0
+    if (isFinite(length)) {
+      length = length >>> 0
+      if (encoding === undefined) encoding = 'utf8'
+    } else {
+      encoding = length
+      length = undefined
+    }
+  } else {
+    throw new Error(
+      'Buffer.write(string, encoding, offset[, length]) is no longer supported'
+    )
+  }
+
+  var remaining = this.length - offset
+  if (length === undefined || length > remaining) length = remaining
+
+  if ((string.length > 0 && (length < 0 || offset < 0)) || offset > this.length) {
+    throw new RangeError('Attempt to write outside buffer bounds')
+  }
+
+  if (!encoding) encoding = 'utf8'
+
+  var loweredCase = false
+  for (;;) {
+    switch (encoding) {
+      case 'hex':
+        return hexWrite(this, string, offset, length)
+
+      case 'utf8':
+      case 'utf-8':
+        return utf8Write(this, string, offset, length)
+
+      case 'ascii':
+      case 'latin1':
+      case 'binary':
+        return asciiWrite(this, string, offset, length)
+
+      case 'base64':
+        // Warning: maxLength not taken into account in base64Write
+        return base64Write(this, string, offset, length)
+
+      case 'ucs2':
+      case 'ucs-2':
+      case 'utf16le':
+      case 'utf-16le':
+        return ucs2Write(this, string, offset, length)
+
+      default:
+        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding)
+        encoding = ('' + encoding).toLowerCase()
+        loweredCase = true
+    }
+  }
+}
+
+Buffer.prototype.toJSON = function toJSON () {
+  return {
+    type: 'Buffer',
+    data: Array.prototype.slice.call(this._arr || this, 0)
+  }
+}
+
+function base64Slice (buf, start, end) {
+  if (start === 0 && end === buf.length) {
+    return base64.fromByteArray(buf)
+  } else {
+    return base64.fromByteArray(buf.slice(start, end))
+  }
+}
+
+function utf8Slice (buf, start, end) {
+  end = Math.min(buf.length, end)
+  var res = []
+
+  var i = start
+  while (i < end) {
+    var firstByte = buf[i]
+    var codePoint = null
+    var bytesPerSequence = (firstByte > 0xEF)
+      ? 4
+      : (firstByte > 0xDF)
+          ? 3
+          : (firstByte > 0xBF)
+              ? 2
+              : 1
+
+    if (i + bytesPerSequence <= end) {
+      var secondByte, thirdByte, fourthByte, tempCodePoint
+
+      switch (bytesPerSequence) {
+        case 1:
+          if (firstByte < 0x80) {
+            codePoint = firstByte
+          }
+          break
+        case 2:
+          secondByte = buf[i + 1]
+          if ((secondByte & 0xC0) === 0x80) {
+            tempCodePoint = (firstByte & 0x1F) << 0x6 | (secondByte & 0x3F)
+            if (tempCodePoint > 0x7F) {
+              codePoint = tempCodePoint
+            }
+          }
+          break
+        case 3:
+          secondByte = buf[i + 1]
+          thirdByte = buf[i + 2]
+          if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80) {
+            tempCodePoint = (firstByte & 0xF) << 0xC | (secondByte & 0x3F) << 0x6 | (thirdByte & 0x3F)
+            if (tempCodePoint > 0x7FF && (tempCodePoint < 0xD800 || tempCodePoint > 0xDFFF)) {
+              codePoint = tempCodePoint
+            }
+          }
+          break
+        case 4:
+          secondByte = buf[i + 1]
+          thirdByte = buf[i + 2]
+          fourthByte = buf[i + 3]
+          if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80 && (fourthByte & 0xC0) === 0x80) {
+            tempCodePoint = (firstByte & 0xF) << 0x12 | (secondByte & 0x3F) << 0xC | (thirdByte & 0x3F) << 0x6 | (fourthByte & 0x3F)
+            if (tempCodePoint > 0xFFFF && tempCodePoint < 0x110000) {
+              codePoint = tempCodePoint
+            }
+          }
+      }
+    }
+
+    if (codePoint === null) {
+      // we did not generate a valid codePoint so insert a
+      // replacement char (U+FFFD) and advance only 1 byte
+      codePoint = 0xFFFD
+      bytesPerSequence = 1
+    } else if (codePoint > 0xFFFF) {
+      // encode to utf16 (surrogate pair dance)
+      codePoint -= 0x10000
+      res.push(codePoint >>> 10 & 0x3FF | 0xD800)
+      codePoint = 0xDC00 | codePoint & 0x3FF
+    }
+
+    res.push(codePoint)
+    i += bytesPerSequence
+  }
+
+  return decodeCodePointsArray(res)
+}
+
+// Based on http://stackoverflow.com/a/22747272/680742, the browser with
+// the lowest limit is Chrome, with 0x10000 args.
+// We go 1 magnitude less, for safety
+var MAX_ARGUMENTS_LENGTH = 0x1000
+
+function decodeCodePointsArray (codePoints) {
+  var len = codePoints.length
+  if (len <= MAX_ARGUMENTS_LENGTH) {
+    return String.fromCharCode.apply(String, codePoints) // avoid extra slice()
+  }
+
+  // Decode in chunks to avoid "call stack size exceeded".
+  var res = ''
+  var i = 0
+  while (i < len) {
+    res += String.fromCharCode.apply(
+      String,
+      codePoints.slice(i, i += MAX_ARGUMENTS_LENGTH)
+    )
+  }
+  return res
+}
+
+function asciiSlice (buf, start, end) {
+  var ret = ''
+  end = Math.min(buf.length, end)
+
+  for (var i = start; i < end; ++i) {
+    ret += String.fromCharCode(buf[i] & 0x7F)
+  }
+  return ret
+}
+
+function latin1Slice (buf, start, end) {
+  var ret = ''
+  end = Math.min(buf.length, end)
+
+  for (var i = start; i < end; ++i) {
+    ret += String.fromCharCode(buf[i])
+  }
+  return ret
+}
+
+function hexSlice (buf, start, end) {
+  var len = buf.length
+
+  if (!start || start < 0) start = 0
+  if (!end || end < 0 || end > len) end = len
+
+  var out = ''
+  for (var i = start; i < end; ++i) {
+    out += hexSliceLookupTable[buf[i]]
+  }
+  return out
+}
+
+function utf16leSlice (buf, start, end) {
+  var bytes = buf.slice(start, end)
+  var res = ''
+  // If bytes.length is odd, the last 8 bits must be ignored (same as node.js)
+  for (var i = 0; i < bytes.length - 1; i += 2) {
+    res += String.fromCharCode(bytes[i] + (bytes[i + 1] * 256))
+  }
+  return res
+}
+
+Buffer.prototype.slice = function slice (start, end) {
+  var len = this.length
+  start = ~~start
+  end = end === undefined ? len : ~~end
+
+  if (start < 0) {
+    start += len
+    if (start < 0) start = 0
+  } else if (start > len) {
+    start = len
+  }
+
+  if (end < 0) {
+    end += len
+    if (end < 0) end = 0
+  } else if (end > len) {
+    end = len
+  }
+
+  if (end < start) end = start
+
+  var newBuf = this.subarray(start, end)
+  // Return an augmented `Uint8Array` instance
+  Object.setPrototypeOf(newBuf, Buffer.prototype)
+
+  return newBuf
+}
+
+/*
+ * Need to make sure that buffer isn't trying to write out of bounds.
+ */
+function checkOffset (offset, ext, length) {
+  if ((offset % 1) !== 0 || offset < 0) throw new RangeError('offset is not uint')
+  if (offset + ext > length) throw new RangeError('Trying to access beyond buffer length')
+}
+
+Buffer.prototype.readUintLE =
+Buffer.prototype.readUIntLE = function readUIntLE (offset, byteLength, noAssert) {
+  offset = offset >>> 0
+  byteLength = byteLength >>> 0
+  if (!noAssert) checkOffset(offset, byteLength, this.length)
+
+  var val = this[offset]
+  var mul = 1
+  var i = 0
+  while (++i < byteLength && (mul *= 0x100)) {
+    val += this[offset + i] * mul
+  }
+
+  return val
+}
+
+Buffer.prototype.readUintBE =
+Buffer.prototype.readUIntBE = function readUIntBE (offset, byteLength, noAssert) {
+  offset = offset >>> 0
+  byteLength = byteLength >>> 0
+  if (!noAssert) {
+    checkOffset(offset, byteLength, this.length)
+  }
+
+  var val = this[offset + --byteLength]
+  var mul = 1
+  while (byteLength > 0 && (mul *= 0x100)) {
+    val += this[offset + --byteLength] * mul
+  }
+
+  return val
+}
+
+Buffer.prototype.readUint8 =
+Buffer.prototype.readUInt8 = function readUInt8 (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 1, this.length)
+  return this[offset]
+}
+
+Buffer.prototype.readUint16LE =
+Buffer.prototype.readUInt16LE = function readUInt16LE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 2, this.length)
+  return this[offset] | (this[offset + 1] << 8)
+}
+
+Buffer.prototype.readUint16BE =
+Buffer.prototype.readUInt16BE = function readUInt16BE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 2, this.length)
+  return (this[offset] << 8) | this[offset + 1]
+}
+
+Buffer.prototype.readUint32LE =
+Buffer.prototype.readUInt32LE = function readUInt32LE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 4, this.length)
+
+  return ((this[offset]) |
+      (this[offset + 1] << 8) |
+      (this[offset + 2] << 16)) +
+      (this[offset + 3] * 0x1000000)
+}
+
+Buffer.prototype.readUint32BE =
+Buffer.prototype.readUInt32BE = function readUInt32BE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 4, this.length)
+
+  return (this[offset] * 0x1000000) +
+    ((this[offset + 1] << 16) |
+    (this[offset + 2] << 8) |
+    this[offset + 3])
+}
+
+Buffer.prototype.readIntLE = function readIntLE (offset, byteLength, noAssert) {
+  offset = offset >>> 0
+  byteLength = byteLength >>> 0
+  if (!noAssert) checkOffset(offset, byteLength, this.length)
+
+  var val = this[offset]
+  var mul = 1
+  var i = 0
+  while (++i < byteLength && (mul *= 0x100)) {
+    val += this[offset + i] * mul
+  }
+  mul *= 0x80
+
+  if (val >= mul) val -= Math.pow(2, 8 * byteLength)
+
+  return val
+}
+
+Buffer.prototype.readIntBE = function readIntBE (offset, byteLength, noAssert) {
+  offset = offset >>> 0
+  byteLength = byteLength >>> 0
+  if (!noAssert) checkOffset(offset, byteLength, this.length)
+
+  var i = byteLength
+  var mul = 1
+  var val = this[offset + --i]
+  while (i > 0 && (mul *= 0x100)) {
+    val += this[offset + --i] * mul
+  }
+  mul *= 0x80
+
+  if (val >= mul) val -= Math.pow(2, 8 * byteLength)
+
+  return val
+}
+
+Buffer.prototype.readInt8 = function readInt8 (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 1, this.length)
+  if (!(this[offset] & 0x80)) return (this[offset])
+  return ((0xff - this[offset] + 1) * -1)
+}
+
+Buffer.prototype.readInt16LE = function readInt16LE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 2, this.length)
+  var val = this[offset] | (this[offset + 1] << 8)
+  return (val & 0x8000) ? val | 0xFFFF0000 : val
+}
+
+Buffer.prototype.readInt16BE = function readInt16BE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 2, this.length)
+  var val = this[offset + 1] | (this[offset] << 8)
+  return (val & 0x8000) ? val | 0xFFFF0000 : val
+}
+
+Buffer.prototype.readInt32LE = function readInt32LE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 4, this.length)
+
+  return (this[offset]) |
+    (this[offset + 1] << 8) |
+    (this[offset + 2] << 16) |
+    (this[offset + 3] << 24)
+}
+
+Buffer.prototype.readInt32BE = function readInt32BE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 4, this.length)
+
+  return (this[offset] << 24) |
+    (this[offset + 1] << 16) |
+    (this[offset + 2] << 8) |
+    (this[offset + 3])
+}
+
+Buffer.prototype.readFloatLE = function readFloatLE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 4, this.length)
+  return ieee754.read(this, offset, true, 23, 4)
+}
+
+Buffer.prototype.readFloatBE = function readFloatBE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 4, this.length)
+  return ieee754.read(this, offset, false, 23, 4)
+}
+
+Buffer.prototype.readDoubleLE = function readDoubleLE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 8, this.length)
+  return ieee754.read(this, offset, true, 52, 8)
+}
+
+Buffer.prototype.readDoubleBE = function readDoubleBE (offset, noAssert) {
+  offset = offset >>> 0
+  if (!noAssert) checkOffset(offset, 8, this.length)
+  return ieee754.read(this, offset, false, 52, 8)
+}
+
+function checkInt (buf, value, offset, ext, max, min) {
+  if (!Buffer.isBuffer(buf)) throw new TypeError('"buffer" argument must be a Buffer instance')
+  if (value > max || value < min) throw new RangeError('"value" argument is out of bounds')
+  if (offset + ext > buf.length) throw new RangeError('Index out of range')
+}
+
+Buffer.prototype.writeUintLE =
+Buffer.prototype.writeUIntLE = function writeUIntLE (value, offset, byteLength, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  byteLength = byteLength >>> 0
+  if (!noAssert) {
+    var maxBytes = Math.pow(2, 8 * byteLength) - 1
+    checkInt(this, value, offset, byteLength, maxBytes, 0)
+  }
+
+  var mul = 1
+  var i = 0
+  this[offset] = value & 0xFF
+  while (++i < byteLength && (mul *= 0x100)) {
+    this[offset + i] = (value / mul) & 0xFF
+  }
+
+  return offset + byteLength
+}
+
+Buffer.prototype.writeUintBE =
+Buffer.prototype.writeUIntBE = function writeUIntBE (value, offset, byteLength, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  byteLength = byteLength >>> 0
+  if (!noAssert) {
+    var maxBytes = Math.pow(2, 8 * byteLength) - 1
+    checkInt(this, value, offset, byteLength, maxBytes, 0)
+  }
+
+  var i = byteLength - 1
+  var mul = 1
+  this[offset + i] = value & 0xFF
+  while (--i >= 0 && (mul *= 0x100)) {
+    this[offset + i] = (value / mul) & 0xFF
+  }
+
+  return offset + byteLength
+}
+
+Buffer.prototype.writeUint8 =
+Buffer.prototype.writeUInt8 = function writeUInt8 (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 1, 0xff, 0)
+  this[offset] = (value & 0xff)
+  return offset + 1
+}
+
+Buffer.prototype.writeUint16LE =
+Buffer.prototype.writeUInt16LE = function writeUInt16LE (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
+  this[offset] = (value & 0xff)
+  this[offset + 1] = (value >>> 8)
+  return offset + 2
+}
+
+Buffer.prototype.writeUint16BE =
+Buffer.prototype.writeUInt16BE = function writeUInt16BE (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
+  this[offset] = (value >>> 8)
+  this[offset + 1] = (value & 0xff)
+  return offset + 2
+}
+
+Buffer.prototype.writeUint32LE =
+Buffer.prototype.writeUInt32LE = function writeUInt32LE (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
+  this[offset + 3] = (value >>> 24)
+  this[offset + 2] = (value >>> 16)
+  this[offset + 1] = (value >>> 8)
+  this[offset] = (value & 0xff)
+  return offset + 4
+}
+
+Buffer.prototype.writeUint32BE =
+Buffer.prototype.writeUInt32BE = function writeUInt32BE (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
+  this[offset] = (value >>> 24)
+  this[offset + 1] = (value >>> 16)
+  this[offset + 2] = (value >>> 8)
+  this[offset + 3] = (value & 0xff)
+  return offset + 4
+}
+
+Buffer.prototype.writeIntLE = function writeIntLE (value, offset, byteLength, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) {
+    var limit = Math.pow(2, (8 * byteLength) - 1)
+
+    checkInt(this, value, offset, byteLength, limit - 1, -limit)
+  }
+
+  var i = 0
+  var mul = 1
+  var sub = 0
+  this[offset] = value & 0xFF
+  while (++i < byteLength && (mul *= 0x100)) {
+    if (value < 0 && sub === 0 && this[offset + i - 1] !== 0) {
+      sub = 1
+    }
+    this[offset + i] = ((value / mul) >> 0) - sub & 0xFF
+  }
+
+  return offset + byteLength
+}
+
+Buffer.prototype.writeIntBE = function writeIntBE (value, offset, byteLength, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) {
+    var limit = Math.pow(2, (8 * byteLength) - 1)
+
+    checkInt(this, value, offset, byteLength, limit - 1, -limit)
+  }
+
+  var i = byteLength - 1
+  var mul = 1
+  var sub = 0
+  this[offset + i] = value & 0xFF
+  while (--i >= 0 && (mul *= 0x100)) {
+    if (value < 0 && sub === 0 && this[offset + i + 1] !== 0) {
+      sub = 1
+    }
+    this[offset + i] = ((value / mul) >> 0) - sub & 0xFF
+  }
+
+  return offset + byteLength
+}
+
+Buffer.prototype.writeInt8 = function writeInt8 (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 1, 0x7f, -0x80)
+  if (value < 0) value = 0xff + value + 1
+  this[offset] = (value & 0xff)
+  return offset + 1
+}
+
+Buffer.prototype.writeInt16LE = function writeInt16LE (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
+  this[offset] = (value & 0xff)
+  this[offset + 1] = (value >>> 8)
+  return offset + 2
+}
+
+Buffer.prototype.writeInt16BE = function writeInt16BE (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
+  this[offset] = (value >>> 8)
+  this[offset + 1] = (value & 0xff)
+  return offset + 2
+}
+
+Buffer.prototype.writeInt32LE = function writeInt32LE (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
+  this[offset] = (value & 0xff)
+  this[offset + 1] = (value >>> 8)
+  this[offset + 2] = (value >>> 16)
+  this[offset + 3] = (value >>> 24)
+  return offset + 4
+}
+
+Buffer.prototype.writeInt32BE = function writeInt32BE (value, offset, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
+  if (value < 0) value = 0xffffffff + value + 1
+  this[offset] = (value >>> 24)
+  this[offset + 1] = (value >>> 16)
+  this[offset + 2] = (value >>> 8)
+  this[offset + 3] = (value & 0xff)
+  return offset + 4
+}
+
+function checkIEEE754 (buf, value, offset, ext, max, min) {
+  if (offset + ext > buf.length) throw new RangeError('Index out of range')
+  if (offset < 0) throw new RangeError('Index out of range')
+}
+
+function writeFloat (buf, value, offset, littleEndian, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) {
+    checkIEEE754(buf, value, offset, 4, 3.4028234663852886e+38, -3.4028234663852886e+38)
+  }
+  ieee754.write(buf, value, offset, littleEndian, 23, 4)
+  return offset + 4
+}
+
+Buffer.prototype.writeFloatLE = function writeFloatLE (value, offset, noAssert) {
+  return writeFloat(this, value, offset, true, noAssert)
+}
+
+Buffer.prototype.writeFloatBE = function writeFloatBE (value, offset, noAssert) {
+  return writeFloat(this, value, offset, false, noAssert)
+}
+
+function writeDouble (buf, value, offset, littleEndian, noAssert) {
+  value = +value
+  offset = offset >>> 0
+  if (!noAssert) {
+    checkIEEE754(buf, value, offset, 8, 1.7976931348623157E+308, -1.7976931348623157E+308)
+  }
+  ieee754.write(buf, value, offset, littleEndian, 52, 8)
+  return offset + 8
+}
+
+Buffer.prototype.writeDoubleLE = function writeDoubleLE (value, offset, noAssert) {
+  return writeDouble(this, value, offset, true, noAssert)
+}
+
+Buffer.prototype.writeDoubleBE = function writeDoubleBE (value, offset, noAssert) {
+  return writeDouble(this, value, offset, false, noAssert)
+}
+
+// copy(targetBuffer, targetStart=0, sourceStart=0, sourceEnd=buffer.length)
+Buffer.prototype.copy = function copy (target, targetStart, start, end) {
+  if (!Buffer.isBuffer(target)) throw new TypeError('argument should be a Buffer')
+  if (!start) start = 0
+  if (!end && end !== 0) end = this.length
+  if (targetStart >= target.length) targetStart = target.length
+  if (!targetStart) targetStart = 0
+  if (end > 0 && end < start) end = start
+
+  // Copy 0 bytes; we're done
+  if (end === start) return 0
+  if (target.length === 0 || this.length === 0) return 0
+
+  // Fatal error conditions
+  if (targetStart < 0) {
+    throw new RangeError('targetStart out of bounds')
+  }
+  if (start < 0 || start >= this.length) throw new RangeError('Index out of range')
+  if (end < 0) throw new RangeError('sourceEnd out of bounds')
+
+  // Are we oob?
+  if (end > this.length) end = this.length
+  if (target.length - targetStart < end - start) {
+    end = target.length - targetStart + start
+  }
+
+  var len = end - start
+
+  if (this === target && typeof Uint8Array.prototype.copyWithin === 'function') {
+    // Use built-in when available, missing from IE11
+    this.copyWithin(targetStart, start, end)
+  } else {
+    Uint8Array.prototype.set.call(
+      target,
+      this.subarray(start, end),
+      targetStart
+    )
+  }
+
+  return len
+}
+
+// Usage:
+//    buffer.fill(number[, offset[, end]])
+//    buffer.fill(buffer[, offset[, end]])
+//    buffer.fill(string[, offset[, end]][, encoding])
+Buffer.prototype.fill = function fill (val, start, end, encoding) {
+  // Handle string cases:
+  if (typeof val === 'string') {
+    if (typeof start === 'string') {
+      encoding = start
+      start = 0
+      end = this.length
+    } else if (typeof end === 'string') {
+      encoding = end
+      end = this.length
+    }
+    if (encoding !== undefined && typeof encoding !== 'string') {
+      throw new TypeError('encoding must be a string')
+    }
+    if (typeof encoding === 'string' && !Buffer.isEncoding(encoding)) {
+      throw new TypeError('Unknown encoding: ' + encoding)
+    }
+    if (val.length === 1) {
+      var code = val.charCodeAt(0)
+      if ((encoding === 'utf8' && code < 128) ||
+          encoding === 'latin1') {
+        // Fast path: If `val` fits into a single byte, use that numeric value.
+        val = code
+      }
+    }
+  } else if (typeof val === 'number') {
+    val = val & 255
+  } else if (typeof val === 'boolean') {
+    val = Number(val)
+  }
+
+  // Invalid ranges are not set to a default, so can range check early.
+  if (start < 0 || this.length < start || this.length < end) {
+    throw new RangeError('Out of range index')
+  }
+
+  if (end <= start) {
+    return this
+  }
+
+  start = start >>> 0
+  end = end === undefined ? this.length : end >>> 0
+
+  if (!val) val = 0
+
+  var i
+  if (typeof val === 'number') {
+    for (i = start; i < end; ++i) {
+      this[i] = val
+    }
+  } else {
+    var bytes = Buffer.isBuffer(val)
+      ? val
+      : Buffer.from(val, encoding)
+    var len = bytes.length
+    if (len === 0) {
+      throw new TypeError('The value "' + val +
+        '" is invalid for argument "value"')
+    }
+    for (i = 0; i < end - start; ++i) {
+      this[i + start] = bytes[i % len]
+    }
+  }
+
+  return this
+}
+
+// HELPER FUNCTIONS
+// ================
+
+var INVALID_BASE64_RE = /[^+/0-9A-Za-z-_]/g
+
+function base64clean (str) {
+  // Node takes equal signs as end of the Base64 encoding
+  str = str.split('=')[0]
+  // Node strips out invalid characters like \n and \t from the string, base64-js does not
+  str = str.trim().replace(INVALID_BASE64_RE, '')
+  // Node converts strings with length < 2 to ''
+  if (str.length < 2) return ''
+  // Node allows for non-padded base64 strings (missing trailing ===), base64-js does not
+  while (str.length % 4 !== 0) {
+    str = str + '='
+  }
+  return str
+}
+
+function utf8ToBytes (string, units) {
+  units = units || Infinity
+  var codePoint
+  var length = string.length
+  var leadSurrogate = null
+  var bytes = []
+
+  for (var i = 0; i < length; ++i) {
+    codePoint = string.charCodeAt(i)
+
+    // is surrogate component
+    if (codePoint > 0xD7FF && codePoint < 0xE000) {
+      // last char was a lead
+      if (!leadSurrogate) {
+        // no lead yet
+        if (codePoint > 0xDBFF) {
+          // unexpected trail
+          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
+          continue
+        } else if (i + 1 === length) {
+          // unpaired lead
+          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
+          continue
+        }
+
+        // valid lead
+        leadSurrogate = codePoint
+
+        continue
+      }
+
+      // 2 leads in a row
+      if (codePoint < 0xDC00) {
+        if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
+        leadSurrogate = codePoint
+        continue
+      }
+
+      // valid surrogate pair
+      codePoint = (leadSurrogate - 0xD800 << 10 | codePoint - 0xDC00) + 0x10000
+    } else if (leadSurrogate) {
+      // valid bmp char, but last char was a lead
+      if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
+    }
+
+    leadSurrogate = null
+
+    // encode utf8
+    if (codePoint < 0x80) {
+      if ((units -= 1) < 0) break
+      bytes.push(codePoint)
+    } else if (codePoint < 0x800) {
+      if ((units -= 2) < 0) break
+      bytes.push(
+        codePoint >> 0x6 | 0xC0,
+        codePoint & 0x3F | 0x80
+      )
+    } else if (codePoint < 0x10000) {
+      if ((units -= 3) < 0) break
+      bytes.push(
+        codePoint >> 0xC | 0xE0,
+        codePoint >> 0x6 & 0x3F | 0x80,
+        codePoint & 0x3F | 0x80
+      )
+    } else if (codePoint < 0x110000) {
+      if ((units -= 4) < 0) break
+      bytes.push(
+        codePoint >> 0x12 | 0xF0,
+        codePoint >> 0xC & 0x3F | 0x80,
+        codePoint >> 0x6 & 0x3F | 0x80,
+        codePoint & 0x3F | 0x80
+      )
+    } else {
+      throw new Error('Invalid code point')
+    }
+  }
+
+  return bytes
+}
+
+function asciiToBytes (str) {
+  var byteArray = []
+  for (var i = 0; i < str.length; ++i) {
+    // Node's code seems to be doing this and not & 0x7F..
+    byteArray.push(str.charCodeAt(i) & 0xFF)
+  }
+  return byteArray
+}
+
+function utf16leToBytes (str, units) {
+  var c, hi, lo
+  var byteArray = []
+  for (var i = 0; i < str.length; ++i) {
+    if ((units -= 2) < 0) break
+
+    c = str.charCodeAt(i)
+    hi = c >> 8
+    lo = c % 256
+    byteArray.push(lo)
+    byteArray.push(hi)
+  }
+
+  return byteArray
+}
+
+function base64ToBytes (str) {
+  return base64.toByteArray(base64clean(str))
+}
+
+function blitBuffer (src, dst, offset, length) {
+  for (var i = 0; i < length; ++i) {
+    if ((i + offset >= dst.length) || (i >= src.length)) break
+    dst[i + offset] = src[i]
+  }
+  return i
+}
+
+// ArrayBuffer or Uint8Array objects from other contexts (i.e. iframes) do not pass
+// the `instanceof` check but they should be treated as of that type.
+// See: https://github.com/feross/buffer/issues/166
+function isInstance (obj, type) {
+  return obj instanceof type ||
+    (obj != null && obj.constructor != null && obj.constructor.name != null &&
+      obj.constructor.name === type.name)
+}
+function numberIsNaN (obj) {
+  // For IE11 support
+  return obj !== obj // eslint-disable-line no-self-compare
+}
+
+// Create lookup table for `toString('hex')`
+// See: https://github.com/feross/buffer/issues/219
+var hexSliceLookupTable = (function () {
+  var alphabet = '0123456789abcdef'
+  var table = new Array(256)
+  for (var i = 0; i < 16; ++i) {
+    var i16 = i * 16
+    for (var j = 0; j < 16; ++j) {
+      table[i16 + j] = alphabet[i] + alphabet[j]
+    }
+  }
+  return table
+})()
diff --git a/server/node_modules/buffer/package.json b/server/node_modules/buffer/package.json
new file mode 100644
index 0000000..3b1b498
--- /dev/null
+++ b/server/node_modules/buffer/package.json
@@ -0,0 +1,96 @@
+{
+  "name": "buffer",
+  "description": "Node.js Buffer API, for the browser",
+  "version": "5.7.1",
+  "author": {
+    "name": "Feross Aboukhadijeh",
+    "email": "feross@feross.org",
+    "url": "https://feross.org"
+  },
+  "bugs": {
+    "url": "https://github.com/feross/buffer/issues"
+  },
+  "contributors": [
+    "Romain Beauxis <toots@rastageeks.org>",
+    "James Halliday <mail@substack.net>"
+  ],
+  "dependencies": {
+    "base64-js": "^1.3.1",
+    "ieee754": "^1.1.13"
+  },
+  "devDependencies": {
+    "airtap": "^3.0.0",
+    "benchmark": "^2.1.4",
+    "browserify": "^17.0.0",
+    "concat-stream": "^2.0.0",
+    "hyperquest": "^2.1.3",
+    "is-buffer": "^2.0.4",
+    "is-nan": "^1.3.0",
+    "split": "^1.0.1",
+    "standard": "*",
+    "tape": "^5.0.1",
+    "through2": "^4.0.2",
+    "uglify-js": "^3.11.3"
+  },
+  "homepage": "https://github.com/feross/buffer",
+  "jspm": {
+    "map": {
+      "./index.js": {
+        "node": "@node/buffer"
+      }
+    }
+  },
+  "keywords": [
+    "arraybuffer",
+    "browser",
+    "browserify",
+    "buffer",
+    "compatible",
+    "dataview",
+    "uint8array"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/feross/buffer.git"
+  },
+  "scripts": {
+    "perf": "browserify --debug perf/bracket-notation.js > perf/bundle.js && open perf/index.html",
+    "perf-node": "node perf/bracket-notation.js && node perf/concat.js && node perf/copy-big.js && node perf/copy.js && node perf/new-big.js && node perf/new.js && node perf/readDoubleBE.js && node perf/readFloatBE.js && node perf/readUInt32LE.js && node perf/slice.js && node perf/writeFloatBE.js",
+    "size": "browserify -r ./ | uglifyjs -c -m | gzip | wc -c",
+    "test": "standard && node ./bin/test.js",
+    "test-browser-es5": "airtap -- test/*.js",
+    "test-browser-es5-local": "airtap --local -- test/*.js",
+    "test-browser-es6": "airtap -- test/*.js test/node/*.js",
+    "test-browser-es6-local": "airtap --local -- test/*.js test/node/*.js",
+    "test-node": "tape test/*.js test/node/*.js",
+    "update-authors": "./bin/update-authors.sh"
+  },
+  "standard": {
+    "ignore": [
+      "test/node/**/*.js",
+      "test/common.js",
+      "test/_polyfill.js",
+      "perf/**/*.js"
+    ],
+    "globals": [
+      "SharedArrayBuffer"
+    ]
+  },
+  "funding": [
+    {
+      "type": "github",
+      "url": "https://github.com/sponsors/feross"
+    },
+    {
+      "type": "patreon",
+      "url": "https://www.patreon.com/feross"
+    },
+    {
+      "type": "consulting",
+      "url": "https://feross.org/support"
+    }
+  ]
+}
diff --git a/server/node_modules/busboy/.eslintrc.js b/server/node_modules/busboy/.eslintrc.js
new file mode 100644
index 0000000..be9311d
--- /dev/null
+++ b/server/node_modules/busboy/.eslintrc.js
@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = {
+  extends: '@mscdex/eslint-config',
+};
diff --git a/server/node_modules/busboy/.github/workflows/ci.yml b/server/node_modules/busboy/.github/workflows/ci.yml
new file mode 100644
index 0000000..799bae0
--- /dev/null
+++ b/server/node_modules/busboy/.github/workflows/ci.yml
@@ -0,0 +1,24 @@
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches: [ master ]
+
+jobs:
+  tests-linux:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version: [10.16.0, 10.x, 12.x, 14.x, 16.x]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+      - name: Install module
+        run: npm install
+      - name: Run tests
+        run: npm test
diff --git a/server/node_modules/busboy/.github/workflows/lint.yml b/server/node_modules/busboy/.github/workflows/lint.yml
new file mode 100644
index 0000000..9f9e1f5
--- /dev/null
+++ b/server/node_modules/busboy/.github/workflows/lint.yml
@@ -0,0 +1,23 @@
+name: lint
+
+on:
+  pull_request:
+  push:
+    branches: [ master ]
+
+env:
+  NODE_VERSION: 16.x
+
+jobs:
+  lint-js:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js ${{ env.NODE_VERSION }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ env.NODE_VERSION }}
+      - name: Install ESLint + ESLint configs/plugins
+        run: npm install --only=dev
+      - name: Lint files
+        run: npm run lint
diff --git a/server/node_modules/busboy/LICENSE b/server/node_modules/busboy/LICENSE
new file mode 100644
index 0000000..290762e
--- /dev/null
+++ b/server/node_modules/busboy/LICENSE
@@ -0,0 +1,19 @@
+Copyright Brian White. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/busboy/README.md b/server/node_modules/busboy/README.md
new file mode 100644
index 0000000..654af30
--- /dev/null
+++ b/server/node_modules/busboy/README.md
@@ -0,0 +1,191 @@
+# Description
+
+A node.js module for parsing incoming HTML form data.
+
+Changes (breaking or otherwise) in v1.0.0 can be found [here](https://github.com/mscdex/busboy/issues/266).
+
+# Requirements
+
+* [node.js](http://nodejs.org/) -- v10.16.0 or newer
+
+
+# Install
+
+    npm install busboy
+
+
+# Examples
+
+* Parsing (multipart) with default options:
+
+```js
+const http = require('http');
+
+const busboy = require('busboy');
+
+http.createServer((req, res) => {
+  if (req.method === 'POST') {
+    console.log('POST request');
+    const bb = busboy({ headers: req.headers });
+    bb.on('file', (name, file, info) => {
+      const { filename, encoding, mimeType } = info;
+      console.log(
+        `File [${name}]: filename: %j, encoding: %j, mimeType: %j`,
+        filename,
+        encoding,
+        mimeType
+      );
+      file.on('data', (data) => {
+        console.log(`File [${name}] got ${data.length} bytes`);
+      }).on('close', () => {
+        console.log(`File [${name}] done`);
+      });
+    });
+    bb.on('field', (name, val, info) => {
+      console.log(`Field [${name}]: value: %j`, val);
+    });
+    bb.on('close', () => {
+      console.log('Done parsing form!');
+      res.writeHead(303, { Connection: 'close', Location: '/' });
+      res.end();
+    });
+    req.pipe(bb);
+  } else if (req.method === 'GET') {
+    res.writeHead(200, { Connection: 'close' });
+    res.end(`
+      <html>
+        <head></head>
+        <body>
+          <form method="POST" enctype="multipart/form-data">
+            <input type="file" name="filefield"><br />
+            <input type="text" name="textfield"><br />
+            <input type="submit">
+          </form>
+        </body>
+      </html>
+    `);
+  }
+}).listen(8000, () => {
+  console.log('Listening for requests');
+});
+
+// Example output:
+//
+// Listening for requests
+//   < ... form submitted ... >
+// POST request
+// File [filefield]: filename: "logo.jpg", encoding: "binary", mime: "image/jpeg"
+// File [filefield] got 11912 bytes
+// Field [textfield]: value: "testing! :-)"
+// File [filefield] done
+// Done parsing form!
+```
+
+* Save all incoming files to disk:
+
+```js
+const { randomFillSync } = require('crypto');
+const fs = require('fs');
+const http = require('http');
+const os = require('os');
+const path = require('path');
+
+const busboy = require('busboy');
+
+const random = (() => {
+  const buf = Buffer.alloc(16);
+  return () => randomFillSync(buf).toString('hex');
+})();
+
+http.createServer((req, res) => {
+  if (req.method === 'POST') {
+    const bb = busboy({ headers: req.headers });
+    bb.on('file', (name, file, info) => {
+      const saveTo = path.join(os.tmpdir(), `busboy-upload-${random()}`);
+      file.pipe(fs.createWriteStream(saveTo));
+    });
+    bb.on('close', () => {
+      res.writeHead(200, { 'Connection': 'close' });
+      res.end(`That's all folks!`);
+    });
+    req.pipe(bb);
+    return;
+  }
+  res.writeHead(404);
+  res.end();
+}).listen(8000, () => {
+  console.log('Listening for requests');
+});
+```
+
+
+# API
+
+## Exports
+
+`busboy` exports a single function:
+
+**( _function_ )**(< _object_ >config) - Creates and returns a new _Writable_ form parser stream.
+
+* Valid `config` properties:
+
+    * **headers** - _object_ - These are the HTTP headers of the incoming request, which are used by individual parsers.
+
+    * **highWaterMark** - _integer_ - highWaterMark to use for the parser stream. **Default:** node's _stream.Writable_ default.
+
+    * **fileHwm** - _integer_ - highWaterMark to use for individual file streams. **Default:** node's _stream.Readable_ default.
+
+    * **defCharset** - _string_ - Default character set to use when one isn't defined. **Default:** `'utf8'`.
+
+    * **defParamCharset** - _string_ - For multipart forms, the default character set to use for values of part header parameters (e.g. filename) that are not extended parameters (that contain an explicit charset). **Default:** `'latin1'`.
+
+    * **preservePath** - _boolean_ - If paths in filenames from file parts in a `'multipart/form-data'` request shall be preserved. **Default:** `false`.
+
+    * **limits** - _object_ - Various limits on incoming data. Valid properties are:
+
+        * **fieldNameSize** - _integer_ - Max field name size (in bytes). **Default:** `100`.
+
+        * **fieldSize** - _integer_ - Max field value size (in bytes). **Default:** `1048576` (1MB).
+
+        * **fields** - _integer_ - Max number of non-file fields. **Default:** `Infinity`.
+
+        * **fileSize** - _integer_ - For multipart forms, the max file size (in bytes). **Default:** `Infinity`.
+
+        * **files** - _integer_ - For multipart forms, the max number of file fields. **Default:** `Infinity`.
+
+        * **parts** - _integer_ - For multipart forms, the max number of parts (fields + files). **Default:** `Infinity`.
+
+        * **headerPairs** - _integer_ - For multipart forms, the max number of header key-value pairs to parse. **Default:** `2000` (same as node's http module).
+
+This function can throw exceptions if there is something wrong with the values in `config`. For example, if the Content-Type in `headers` is missing entirely, is not a supported type, or is missing the boundary for `'multipart/form-data'` requests.
+
+## (Special) Parser stream events
+
+* **file**(< _string_ >name, < _Readable_ >stream, < _object_ >info) - Emitted for each new file found. `name` contains the form field name. `stream` is a _Readable_ stream containing the file's data. No transformations/conversions (e.g. base64 to raw binary) are done on the file's data. `info` contains the following properties:
+
+    * `filename` - _string_ - If supplied, this contains the file's filename. **WARNING:** You should almost _never_ use this value as-is (especially if you are using `preservePath: true` in your `config`) as it could contain malicious input. You are better off generating your own (safe) filenames, or at the very least using a hash of the filename.
+
+    * `encoding` - _string_ - The file's `'Content-Transfer-Encoding'` value.
+
+    * `mimeType` - _string_ - The file's `'Content-Type'` value.
+
+    **Note:** If you listen for this event, you should always consume the `stream` whether you care about its contents or not (you can simply do `stream.resume();` if you want to discard/skip the contents), otherwise the `'finish'`/`'close'` event will never fire on the busboy parser stream.
+    However, if you aren't accepting files, you can either simply not listen for the `'file'` event at all or set `limits.files` to `0`, and any/all files will be automatically skipped (these skipped files will still count towards any configured `limits.files` and `limits.parts` limits though).
+
+    **Note:** If a configured `limits.fileSize` limit was reached for a file, `stream` will both have a boolean property `truncated` set to `true` (best checked at the end of the stream) and emit a `'limit'` event to notify you when this happens.
+
+* **field**(< _string_ >name, < _string_ >value, < _object_ >info) - Emitted for each new non-file field found. `name` contains the form field name. `value` contains the string value of the field. `info` contains the following properties:
+
+    * `nameTruncated` - _boolean_ - Whether `name` was truncated or not (due to a configured `limits.fieldNameSize` limit)
+
+    * `valueTruncated` - _boolean_ - Whether `value` was truncated or not (due to a configured `limits.fieldSize` limit)
+
+    * `encoding` - _string_ - The field's `'Content-Transfer-Encoding'` value.
+
+    * `mimeType` - _string_ - The field's `'Content-Type'` value.
+
+* **partsLimit**() - Emitted when the configured `limits.parts` limit has been reached. No more `'file'` or `'field'` events will be emitted.
+
+* **filesLimit**() - Emitted when the configured `limits.files` limit has been reached. No more `'file'` events will be emitted.
+
+* **fieldsLimit**() - Emitted when the configured `limits.fields` limit has been reached. No more `'field'` events will be emitted.
diff --git a/server/node_modules/busboy/bench/bench-multipart-fields-100mb-big.js b/server/node_modules/busboy/bench/bench-multipart-fields-100mb-big.js
new file mode 100644
index 0000000..ef15729
--- /dev/null
+++ b/server/node_modules/busboy/bench/bench-multipart-fields-100mb-big.js
@@ -0,0 +1,149 @@
+'use strict';
+
+function createMultipartBuffers(boundary, sizes) {
+  const bufs = [];
+  for (let i = 0; i < sizes.length; ++i) {
+    const mb = sizes[i] * 1024 * 1024;
+    bufs.push(Buffer.from([
+      `--${boundary}`,
+      `content-disposition: form-data; name="field${i + 1}"`,
+      '',
+      '0'.repeat(mb),
+      '',
+    ].join('\r\n')));
+  }
+  bufs.push(Buffer.from([
+    `--${boundary}--`,
+    '',
+  ].join('\r\n')));
+  return bufs;
+}
+
+const boundary = '-----------------------------168072824752491622650073';
+const buffers = createMultipartBuffers(boundary, [
+  10,
+  10,
+  10,
+  20,
+  50,
+]);
+const calls = {
+  partBegin: 0,
+  headerField: 0,
+  headerValue: 0,
+  headerEnd: 0,
+  headersEnd: 0,
+  partData: 0,
+  partEnd: 0,
+  end: 0,
+};
+
+const moduleName = process.argv[2];
+switch (moduleName) {
+  case 'busboy': {
+    const busboy = require('busboy');
+
+    const parser = busboy({
+      limits: {
+        fieldSizeLimit: Infinity,
+      },
+      headers: {
+        'content-type': `multipart/form-data; boundary=${boundary}`,
+      },
+    });
+    parser.on('field', (name, val, info) => {
+      ++calls.partBegin;
+      ++calls.partData;
+      ++calls.partEnd;
+    }).on('close', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    });
+
+    console.time(moduleName);
+    for (const buf of buffers)
+      parser.write(buf);
+    break;
+  }
+
+  case 'formidable': {
+    const { MultipartParser } = require('formidable');
+
+    const parser = new MultipartParser();
+    parser.initWithBoundary(boundary);
+    parser.on('data', ({ name }) => {
+      ++calls[name];
+      if (name === 'end')
+        console.timeEnd(moduleName);
+    });
+
+    console.time(moduleName);
+    for (const buf of buffers)
+      parser.write(buf);
+
+    break;
+  }
+
+  case 'multiparty': {
+    const { Readable } = require('stream');
+
+    const { Form } = require('multiparty');
+
+    const form = new Form({
+      maxFieldsSize: Infinity,
+      maxFields: Infinity,
+      maxFilesSize: Infinity,
+      autoFields: false,
+      autoFiles: false,
+    });
+
+    const req = new Readable({ read: () => {} });
+    req.headers = {
+      'content-type': `multipart/form-data; boundary=${boundary}`,
+    };
+
+    function hijack(name, fn) {
+      const oldFn = form[name];
+      form[name] = function() {
+        fn();
+        return oldFn.apply(this, arguments);
+      };
+    }
+
+    hijack('onParseHeaderField', () => {
+      ++calls.headerField;
+    });
+    hijack('onParseHeaderValue', () => {
+      ++calls.headerValue;
+    });
+    hijack('onParsePartBegin', () => {
+      ++calls.partBegin;
+    });
+    hijack('onParsePartData', () => {
+      ++calls.partData;
+    });
+    hijack('onParsePartEnd', () => {
+      ++calls.partEnd;
+    });
+
+    form.on('close', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    }).on('part', (p) => p.resume());
+
+    console.time(moduleName);
+    form.parse(req);
+    for (const buf of buffers)
+      req.push(buf);
+    req.push(null);
+
+    break;
+  }
+
+  default:
+    if (moduleName === undefined)
+      console.error('Missing parser module name');
+    else
+      console.error(`Invalid parser module name: ${moduleName}`);
+    process.exit(1);
+}
diff --git a/server/node_modules/busboy/bench/bench-multipart-fields-100mb-small.js b/server/node_modules/busboy/bench/bench-multipart-fields-100mb-small.js
new file mode 100644
index 0000000..f32d421
--- /dev/null
+++ b/server/node_modules/busboy/bench/bench-multipart-fields-100mb-small.js
@@ -0,0 +1,143 @@
+'use strict';
+
+function createMultipartBuffers(boundary, sizes) {
+  const bufs = [];
+  for (let i = 0; i < sizes.length; ++i) {
+    const mb = sizes[i] * 1024 * 1024;
+    bufs.push(Buffer.from([
+      `--${boundary}`,
+      `content-disposition: form-data; name="field${i + 1}"`,
+      '',
+      '0'.repeat(mb),
+      '',
+    ].join('\r\n')));
+  }
+  bufs.push(Buffer.from([
+    `--${boundary}--`,
+    '',
+  ].join('\r\n')));
+  return bufs;
+}
+
+const boundary = '-----------------------------168072824752491622650073';
+const buffers = createMultipartBuffers(boundary, (new Array(100)).fill(1));
+const calls = {
+  partBegin: 0,
+  headerField: 0,
+  headerValue: 0,
+  headerEnd: 0,
+  headersEnd: 0,
+  partData: 0,
+  partEnd: 0,
+  end: 0,
+};
+
+const moduleName = process.argv[2];
+switch (moduleName) {
+  case 'busboy': {
+    const busboy = require('busboy');
+
+    const parser = busboy({
+      limits: {
+        fieldSizeLimit: Infinity,
+      },
+      headers: {
+        'content-type': `multipart/form-data; boundary=${boundary}`,
+      },
+    });
+    parser.on('field', (name, val, info) => {
+      ++calls.partBegin;
+      ++calls.partData;
+      ++calls.partEnd;
+    }).on('close', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    });
+
+    console.time(moduleName);
+    for (const buf of buffers)
+      parser.write(buf);
+    break;
+  }
+
+  case 'formidable': {
+    const { MultipartParser } = require('formidable');
+
+    const parser = new MultipartParser();
+    parser.initWithBoundary(boundary);
+    parser.on('data', ({ name }) => {
+      ++calls[name];
+      if (name === 'end')
+        console.timeEnd(moduleName);
+    });
+
+    console.time(moduleName);
+    for (const buf of buffers)
+      parser.write(buf);
+
+    break;
+  }
+
+  case 'multiparty': {
+    const { Readable } = require('stream');
+
+    const { Form } = require('multiparty');
+
+    const form = new Form({
+      maxFieldsSize: Infinity,
+      maxFields: Infinity,
+      maxFilesSize: Infinity,
+      autoFields: false,
+      autoFiles: false,
+    });
+
+    const req = new Readable({ read: () => {} });
+    req.headers = {
+      'content-type': `multipart/form-data; boundary=${boundary}`,
+    };
+
+    function hijack(name, fn) {
+      const oldFn = form[name];
+      form[name] = function() {
+        fn();
+        return oldFn.apply(this, arguments);
+      };
+    }
+
+    hijack('onParseHeaderField', () => {
+      ++calls.headerField;
+    });
+    hijack('onParseHeaderValue', () => {
+      ++calls.headerValue;
+    });
+    hijack('onParsePartBegin', () => {
+      ++calls.partBegin;
+    });
+    hijack('onParsePartData', () => {
+      ++calls.partData;
+    });
+    hijack('onParsePartEnd', () => {
+      ++calls.partEnd;
+    });
+
+    form.on('close', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    }).on('part', (p) => p.resume());
+
+    console.time(moduleName);
+    form.parse(req);
+    for (const buf of buffers)
+      req.push(buf);
+    req.push(null);
+
+    break;
+  }
+
+  default:
+    if (moduleName === undefined)
+      console.error('Missing parser module name');
+    else
+      console.error(`Invalid parser module name: ${moduleName}`);
+    process.exit(1);
+}
diff --git a/server/node_modules/busboy/bench/bench-multipart-files-100mb-big.js b/server/node_modules/busboy/bench/bench-multipart-files-100mb-big.js
new file mode 100644
index 0000000..b46bdee
--- /dev/null
+++ b/server/node_modules/busboy/bench/bench-multipart-files-100mb-big.js
@@ -0,0 +1,154 @@
+'use strict';
+
+function createMultipartBuffers(boundary, sizes) {
+  const bufs = [];
+  for (let i = 0; i < sizes.length; ++i) {
+    const mb = sizes[i] * 1024 * 1024;
+    bufs.push(Buffer.from([
+      `--${boundary}`,
+      `content-disposition: form-data; name="file${i + 1}"; `
+        + `filename="random${i + 1}.bin"`,
+      'content-type: application/octet-stream',
+      '',
+      '0'.repeat(mb),
+      '',
+    ].join('\r\n')));
+  }
+  bufs.push(Buffer.from([
+    `--${boundary}--`,
+    '',
+  ].join('\r\n')));
+  return bufs;
+}
+
+const boundary = '-----------------------------168072824752491622650073';
+const buffers = createMultipartBuffers(boundary, [
+  10,
+  10,
+  10,
+  20,
+  50,
+]);
+const calls = {
+  partBegin: 0,
+  headerField: 0,
+  headerValue: 0,
+  headerEnd: 0,
+  headersEnd: 0,
+  partData: 0,
+  partEnd: 0,
+  end: 0,
+};
+
+const moduleName = process.argv[2];
+switch (moduleName) {
+  case 'busboy': {
+    const busboy = require('busboy');
+
+    const parser = busboy({
+      limits: {
+        fieldSizeLimit: Infinity,
+      },
+      headers: {
+        'content-type': `multipart/form-data; boundary=${boundary}`,
+      },
+    });
+    parser.on('file', (name, stream, info) => {
+      ++calls.partBegin;
+      stream.on('data', (chunk) => {
+        ++calls.partData;
+      }).on('end', () => {
+        ++calls.partEnd;
+      });
+    }).on('close', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    });
+
+    console.time(moduleName);
+    for (const buf of buffers)
+      parser.write(buf);
+    break;
+  }
+
+  case 'formidable': {
+    const { MultipartParser } = require('formidable');
+
+    const parser = new MultipartParser();
+    parser.initWithBoundary(boundary);
+    parser.on('data', ({ name }) => {
+      ++calls[name];
+      if (name === 'end')
+        console.timeEnd(moduleName);
+    });
+
+    console.time(moduleName);
+    for (const buf of buffers)
+      parser.write(buf);
+
+    break;
+  }
+
+  case 'multiparty': {
+    const { Readable } = require('stream');
+
+    const { Form } = require('multiparty');
+
+    const form = new Form({
+      maxFieldsSize: Infinity,
+      maxFields: Infinity,
+      maxFilesSize: Infinity,
+      autoFields: false,
+      autoFiles: false,
+    });
+
+    const req = new Readable({ read: () => {} });
+    req.headers = {
+      'content-type': `multipart/form-data; boundary=${boundary}`,
+    };
+
+    function hijack(name, fn) {
+      const oldFn = form[name];
+      form[name] = function() {
+        fn();
+        return oldFn.apply(this, arguments);
+      };
+    }
+
+    hijack('onParseHeaderField', () => {
+      ++calls.headerField;
+    });
+    hijack('onParseHeaderValue', () => {
+      ++calls.headerValue;
+    });
+    hijack('onParsePartBegin', () => {
+      ++calls.partBegin;
+    });
+    hijack('onParsePartData', () => {
+      ++calls.partData;
+    });
+    hijack('onParsePartEnd', () => {
+      ++calls.partEnd;
+    });
+
+    form.on('close', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    }).on('part', (p) => p.resume());
+
+    console.time(moduleName);
+    form.parse(req);
+    for (const buf of buffers)
+      req.push(buf);
+    req.push(null);
+
+    break;
+  }
+
+  default:
+    if (moduleName === undefined)
+      console.error('Missing parser module name');
+    else
+      console.error(`Invalid parser module name: ${moduleName}`);
+    process.exit(1);
+}
diff --git a/server/node_modules/busboy/bench/bench-multipart-files-100mb-small.js b/server/node_modules/busboy/bench/bench-multipart-files-100mb-small.js
new file mode 100644
index 0000000..46b5dff
--- /dev/null
+++ b/server/node_modules/busboy/bench/bench-multipart-files-100mb-small.js
@@ -0,0 +1,148 @@
+'use strict';
+
+function createMultipartBuffers(boundary, sizes) {
+  const bufs = [];
+  for (let i = 0; i < sizes.length; ++i) {
+    const mb = sizes[i] * 1024 * 1024;
+    bufs.push(Buffer.from([
+      `--${boundary}`,
+      `content-disposition: form-data; name="file${i + 1}"; `
+        + `filename="random${i + 1}.bin"`,
+      'content-type: application/octet-stream',
+      '',
+      '0'.repeat(mb),
+      '',
+    ].join('\r\n')));
+  }
+  bufs.push(Buffer.from([
+    `--${boundary}--`,
+    '',
+  ].join('\r\n')));
+  return bufs;
+}
+
+const boundary = '-----------------------------168072824752491622650073';
+const buffers = createMultipartBuffers(boundary, (new Array(100)).fill(1));
+const calls = {
+  partBegin: 0,
+  headerField: 0,
+  headerValue: 0,
+  headerEnd: 0,
+  headersEnd: 0,
+  partData: 0,
+  partEnd: 0,
+  end: 0,
+};
+
+const moduleName = process.argv[2];
+switch (moduleName) {
+  case 'busboy': {
+    const busboy = require('busboy');
+
+    const parser = busboy({
+      limits: {
+        fieldSizeLimit: Infinity,
+      },
+      headers: {
+        'content-type': `multipart/form-data; boundary=${boundary}`,
+      },
+    });
+    parser.on('file', (name, stream, info) => {
+      ++calls.partBegin;
+      stream.on('data', (chunk) => {
+        ++calls.partData;
+      }).on('end', () => {
+        ++calls.partEnd;
+      });
+    }).on('close', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    });
+
+    console.time(moduleName);
+    for (const buf of buffers)
+      parser.write(buf);
+    break;
+  }
+
+  case 'formidable': {
+    const { MultipartParser } = require('formidable');
+
+    const parser = new MultipartParser();
+    parser.initWithBoundary(boundary);
+    parser.on('data', ({ name }) => {
+      ++calls[name];
+      if (name === 'end')
+        console.timeEnd(moduleName);
+    });
+
+    console.time(moduleName);
+    for (const buf of buffers)
+      parser.write(buf);
+
+    break;
+  }
+
+  case 'multiparty': {
+    const { Readable } = require('stream');
+
+    const { Form } = require('multiparty');
+
+    const form = new Form({
+      maxFieldsSize: Infinity,
+      maxFields: Infinity,
+      maxFilesSize: Infinity,
+      autoFields: false,
+      autoFiles: false,
+    });
+
+    const req = new Readable({ read: () => {} });
+    req.headers = {
+      'content-type': `multipart/form-data; boundary=${boundary}`,
+    };
+
+    function hijack(name, fn) {
+      const oldFn = form[name];
+      form[name] = function() {
+        fn();
+        return oldFn.apply(this, arguments);
+      };
+    }
+
+    hijack('onParseHeaderField', () => {
+      ++calls.headerField;
+    });
+    hijack('onParseHeaderValue', () => {
+      ++calls.headerValue;
+    });
+    hijack('onParsePartBegin', () => {
+      ++calls.partBegin;
+    });
+    hijack('onParsePartData', () => {
+      ++calls.partData;
+    });
+    hijack('onParsePartEnd', () => {
+      ++calls.partEnd;
+    });
+
+    form.on('close', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    }).on('part', (p) => p.resume());
+
+    console.time(moduleName);
+    form.parse(req);
+    for (const buf of buffers)
+      req.push(buf);
+    req.push(null);
+
+    break;
+  }
+
+  default:
+    if (moduleName === undefined)
+      console.error('Missing parser module name');
+    else
+      console.error(`Invalid parser module name: ${moduleName}`);
+    process.exit(1);
+}
diff --git a/server/node_modules/busboy/bench/bench-urlencoded-fields-100pairs-small.js b/server/node_modules/busboy/bench/bench-urlencoded-fields-100pairs-small.js
new file mode 100644
index 0000000..5c337df
--- /dev/null
+++ b/server/node_modules/busboy/bench/bench-urlencoded-fields-100pairs-small.js
@@ -0,0 +1,101 @@
+'use strict';
+
+const buffers = [
+  Buffer.from(
+    (new Array(100)).fill('').map((_, i) => `key${i}=value${i}`).join('&')
+  ),
+];
+const calls = {
+  field: 0,
+  end: 0,
+};
+
+let n = 3e3;
+
+const moduleName = process.argv[2];
+switch (moduleName) {
+  case 'busboy': {
+    const busboy = require('busboy');
+
+    console.time(moduleName);
+    (function next() {
+      const parser = busboy({
+        limits: {
+          fieldSizeLimit: Infinity,
+        },
+        headers: {
+          'content-type': 'application/x-www-form-urlencoded; charset=utf-8',
+        },
+      });
+      parser.on('field', (name, val, info) => {
+        ++calls.field;
+      }).on('close', () => {
+        ++calls.end;
+        if (--n === 0)
+          console.timeEnd(moduleName);
+        else
+          process.nextTick(next);
+      });
+
+      for (const buf of buffers)
+        parser.write(buf);
+      parser.end();
+    })();
+    break;
+  }
+
+  case 'formidable': {
+    const QuerystringParser =
+      require('formidable/src/parsers/Querystring.js');
+
+    console.time(moduleName);
+    (function next() {
+      const parser = new QuerystringParser();
+      parser.on('data', (obj) => {
+        ++calls.field;
+      }).on('end', () => {
+        ++calls.end;
+        if (--n === 0)
+          console.timeEnd(moduleName);
+        else
+          process.nextTick(next);
+      });
+
+      for (const buf of buffers)
+        parser.write(buf);
+      parser.end();
+    })();
+    break;
+  }
+
+  case 'formidable-streaming': {
+    const QuerystringParser =
+      require('formidable/src/parsers/StreamingQuerystring.js');
+
+    console.time(moduleName);
+    (function next() {
+      const parser = new QuerystringParser();
+      parser.on('data', (obj) => {
+        ++calls.field;
+      }).on('end', () => {
+        ++calls.end;
+        if (--n === 0)
+          console.timeEnd(moduleName);
+        else
+          process.nextTick(next);
+      });
+
+      for (const buf of buffers)
+        parser.write(buf);
+      parser.end();
+    })();
+    break;
+  }
+
+  default:
+    if (moduleName === undefined)
+      console.error('Missing parser module name');
+    else
+      console.error(`Invalid parser module name: ${moduleName}`);
+    process.exit(1);
+}
diff --git a/server/node_modules/busboy/bench/bench-urlencoded-fields-900pairs-small-alt.js b/server/node_modules/busboy/bench/bench-urlencoded-fields-900pairs-small-alt.js
new file mode 100644
index 0000000..1f5645c
--- /dev/null
+++ b/server/node_modules/busboy/bench/bench-urlencoded-fields-900pairs-small-alt.js
@@ -0,0 +1,84 @@
+'use strict';
+
+const buffers = [
+  Buffer.from(
+    (new Array(900)).fill('').map((_, i) => `key${i}=value${i}`).join('&')
+  ),
+];
+const calls = {
+  field: 0,
+  end: 0,
+};
+
+const moduleName = process.argv[2];
+switch (moduleName) {
+  case 'busboy': {
+    const busboy = require('busboy');
+
+    console.time(moduleName);
+    const parser = busboy({
+      limits: {
+        fieldSizeLimit: Infinity,
+      },
+      headers: {
+        'content-type': 'application/x-www-form-urlencoded; charset=utf-8',
+      },
+    });
+    parser.on('field', (name, val, info) => {
+      ++calls.field;
+    }).on('close', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    });
+
+    for (const buf of buffers)
+      parser.write(buf);
+    parser.end();
+    break;
+  }
+
+  case 'formidable': {
+    const QuerystringParser =
+      require('formidable/src/parsers/Querystring.js');
+
+    console.time(moduleName);
+    const parser = new QuerystringParser();
+    parser.on('data', (obj) => {
+      ++calls.field;
+    }).on('end', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    });
+
+    for (const buf of buffers)
+      parser.write(buf);
+    parser.end();
+    break;
+  }
+
+  case 'formidable-streaming': {
+    const QuerystringParser =
+      require('formidable/src/parsers/StreamingQuerystring.js');
+
+    console.time(moduleName);
+    const parser = new QuerystringParser();
+    parser.on('data', (obj) => {
+      ++calls.field;
+    }).on('end', () => {
+      ++calls.end;
+      console.timeEnd(moduleName);
+    });
+
+    for (const buf of buffers)
+      parser.write(buf);
+    parser.end();
+    break;
+  }
+
+  default:
+    if (moduleName === undefined)
+      console.error('Missing parser module name');
+    else
+      console.error(`Invalid parser module name: ${moduleName}`);
+    process.exit(1);
+}
diff --git a/server/node_modules/busboy/lib/index.js b/server/node_modules/busboy/lib/index.js
new file mode 100644
index 0000000..873272d
--- /dev/null
+++ b/server/node_modules/busboy/lib/index.js
@@ -0,0 +1,57 @@
+'use strict';
+
+const { parseContentType } = require('./utils.js');
+
+function getInstance(cfg) {
+  const headers = cfg.headers;
+  const conType = parseContentType(headers['content-type']);
+  if (!conType)
+    throw new Error('Malformed content type');
+
+  for (const type of TYPES) {
+    const matched = type.detect(conType);
+    if (!matched)
+      continue;
+
+    const instanceCfg = {
+      limits: cfg.limits,
+      headers,
+      conType,
+      highWaterMark: undefined,
+      fileHwm: undefined,
+      defCharset: undefined,
+      defParamCharset: undefined,
+      preservePath: false,
+    };
+    if (cfg.highWaterMark)
+      instanceCfg.highWaterMark = cfg.highWaterMark;
+    if (cfg.fileHwm)
+      instanceCfg.fileHwm = cfg.fileHwm;
+    instanceCfg.defCharset = cfg.defCharset;
+    instanceCfg.defParamCharset = cfg.defParamCharset;
+    instanceCfg.preservePath = cfg.preservePath;
+    return new type(instanceCfg);
+  }
+
+  throw new Error(`Unsupported content type: ${headers['content-type']}`);
+}
+
+// Note: types are explicitly listed here for easier bundling
+// See: https://github.com/mscdex/busboy/issues/121
+const TYPES = [
+  require('./types/multipart'),
+  require('./types/urlencoded'),
+].filter(function(typemod) { return typeof typemod.detect === 'function'; });
+
+module.exports = (cfg) => {
+  if (typeof cfg !== 'object' || cfg === null)
+    cfg = {};
+
+  if (typeof cfg.headers !== 'object'
+      || cfg.headers === null
+      || typeof cfg.headers['content-type'] !== 'string') {
+    throw new Error('Missing Content-Type');
+  }
+
+  return getInstance(cfg);
+};
diff --git a/server/node_modules/busboy/lib/types/multipart.js b/server/node_modules/busboy/lib/types/multipart.js
new file mode 100644
index 0000000..cc0d7bb
--- /dev/null
+++ b/server/node_modules/busboy/lib/types/multipart.js
@@ -0,0 +1,653 @@
+'use strict';
+
+const { Readable, Writable } = require('stream');
+
+const StreamSearch = require('streamsearch');
+
+const {
+  basename,
+  convertToUTF8,
+  getDecoder,
+  parseContentType,
+  parseDisposition,
+} = require('../utils.js');
+
+const BUF_CRLF = Buffer.from('\r\n');
+const BUF_CR = Buffer.from('\r');
+const BUF_DASH = Buffer.from('-');
+
+function noop() {}
+
+const MAX_HEADER_PAIRS = 2000; // From node
+const MAX_HEADER_SIZE = 16 * 1024; // From node (its default value)
+
+const HPARSER_NAME = 0;
+const HPARSER_PRE_OWS = 1;
+const HPARSER_VALUE = 2;
+class HeaderParser {
+  constructor(cb) {
+    this.header = Object.create(null);
+    this.pairCount = 0;
+    this.byteCount = 0;
+    this.state = HPARSER_NAME;
+    this.name = '';
+    this.value = '';
+    this.crlf = 0;
+    this.cb = cb;
+  }
+
+  reset() {
+    this.header = Object.create(null);
+    this.pairCount = 0;
+    this.byteCount = 0;
+    this.state = HPARSER_NAME;
+    this.name = '';
+    this.value = '';
+    this.crlf = 0;
+  }
+
+  push(chunk, pos, end) {
+    let start = pos;
+    while (pos < end) {
+      switch (this.state) {
+        case HPARSER_NAME: {
+          let done = false;
+          for (; pos < end; ++pos) {
+            if (this.byteCount === MAX_HEADER_SIZE)
+              return -1;
+            ++this.byteCount;
+            const code = chunk[pos];
+            if (TOKEN[code] !== 1) {
+              if (code !== 58/* ':' */)
+                return -1;
+              this.name += chunk.latin1Slice(start, pos);
+              if (this.name.length === 0)
+                return -1;
+              ++pos;
+              done = true;
+              this.state = HPARSER_PRE_OWS;
+              break;
+            }
+          }
+          if (!done) {
+            this.name += chunk.latin1Slice(start, pos);
+            break;
+          }
+          // FALLTHROUGH
+        }
+        case HPARSER_PRE_OWS: {
+          // Skip optional whitespace
+          let done = false;
+          for (; pos < end; ++pos) {
+            if (this.byteCount === MAX_HEADER_SIZE)
+              return -1;
+            ++this.byteCount;
+            const code = chunk[pos];
+            if (code !== 32/* ' ' */ && code !== 9/* '\t' */) {
+              start = pos;
+              done = true;
+              this.state = HPARSER_VALUE;
+              break;
+            }
+          }
+          if (!done)
+            break;
+          // FALLTHROUGH
+        }
+        case HPARSER_VALUE:
+          switch (this.crlf) {
+            case 0: // Nothing yet
+              for (; pos < end; ++pos) {
+                if (this.byteCount === MAX_HEADER_SIZE)
+                  return -1;
+                ++this.byteCount;
+                const code = chunk[pos];
+                if (FIELD_VCHAR[code] !== 1) {
+                  if (code !== 13/* '\r' */)
+                    return -1;
+                  ++this.crlf;
+                  break;
+                }
+              }
+              this.value += chunk.latin1Slice(start, pos++);
+              break;
+            case 1: // Received CR
+              if (this.byteCount === MAX_HEADER_SIZE)
+                return -1;
+              ++this.byteCount;
+              if (chunk[pos++] !== 10/* '\n' */)
+                return -1;
+              ++this.crlf;
+              break;
+            case 2: { // Received CR LF
+              if (this.byteCount === MAX_HEADER_SIZE)
+                return -1;
+              ++this.byteCount;
+              const code = chunk[pos];
+              if (code === 32/* ' ' */ || code === 9/* '\t' */) {
+                // Folded value
+                start = pos;
+                this.crlf = 0;
+              } else {
+                if (++this.pairCount < MAX_HEADER_PAIRS) {
+                  this.name = this.name.toLowerCase();
+                  if (this.header[this.name] === undefined)
+                    this.header[this.name] = [this.value];
+                  else
+                    this.header[this.name].push(this.value);
+                }
+                if (code === 13/* '\r' */) {
+                  ++this.crlf;
+                  ++pos;
+                } else {
+                  // Assume start of next header field name
+                  start = pos;
+                  this.crlf = 0;
+                  this.state = HPARSER_NAME;
+                  this.name = '';
+                  this.value = '';
+                }
+              }
+              break;
+            }
+            case 3: { // Received CR LF CR
+              if (this.byteCount === MAX_HEADER_SIZE)
+                return -1;
+              ++this.byteCount;
+              if (chunk[pos++] !== 10/* '\n' */)
+                return -1;
+              // End of header
+              const header = this.header;
+              this.reset();
+              this.cb(header);
+              return pos;
+            }
+          }
+          break;
+      }
+    }
+
+    return pos;
+  }
+}
+
+class FileStream extends Readable {
+  constructor(opts, owner) {
+    super(opts);
+    this.truncated = false;
+    this._readcb = null;
+    this.once('end', () => {
+      // We need to make sure that we call any outstanding _writecb() that is
+      // associated with this file so that processing of the rest of the form
+      // can continue. This may not happen if the file stream ends right after
+      // backpressure kicks in, so we force it here.
+      this._read();
+      if (--owner._fileEndsLeft === 0 && owner._finalcb) {
+        const cb = owner._finalcb;
+        owner._finalcb = null;
+        // Make sure other 'end' event handlers get a chance to be executed
+        // before busboy's 'finish' event is emitted
+        process.nextTick(cb);
+      }
+    });
+  }
+  _read(n) {
+    const cb = this._readcb;
+    if (cb) {
+      this._readcb = null;
+      cb();
+    }
+  }
+}
+
+const ignoreData = {
+  push: (chunk, pos) => {},
+  destroy: () => {},
+};
+
+function callAndUnsetCb(self, err) {
+  const cb = self._writecb;
+  self._writecb = null;
+  if (err)
+    self.destroy(err);
+  else if (cb)
+    cb();
+}
+
+function nullDecoder(val, hint) {
+  return val;
+}
+
+class Multipart extends Writable {
+  constructor(cfg) {
+    const streamOpts = {
+      autoDestroy: true,
+      emitClose: true,
+      highWaterMark: (typeof cfg.highWaterMark === 'number'
+                      ? cfg.highWaterMark
+                      : undefined),
+    };
+    super(streamOpts);
+
+    if (!cfg.conType.params || typeof cfg.conType.params.boundary !== 'string')
+      throw new Error('Multipart: Boundary not found');
+
+    const boundary = cfg.conType.params.boundary;
+    const paramDecoder = (typeof cfg.defParamCharset === 'string'
+                            && cfg.defParamCharset
+                          ? getDecoder(cfg.defParamCharset)
+                          : nullDecoder);
+    const defCharset = (cfg.defCharset || 'utf8');
+    const preservePath = cfg.preservePath;
+    const fileOpts = {
+      autoDestroy: true,
+      emitClose: true,
+      highWaterMark: (typeof cfg.fileHwm === 'number'
+                      ? cfg.fileHwm
+                      : undefined),
+    };
+
+    const limits = cfg.limits;
+    const fieldSizeLimit = (limits && typeof limits.fieldSize === 'number'
+                            ? limits.fieldSize
+                            : 1 * 1024 * 1024);
+    const fileSizeLimit = (limits && typeof limits.fileSize === 'number'
+                           ? limits.fileSize
+                           : Infinity);
+    const filesLimit = (limits && typeof limits.files === 'number'
+                        ? limits.files
+                        : Infinity);
+    const fieldsLimit = (limits && typeof limits.fields === 'number'
+                         ? limits.fields
+                         : Infinity);
+    const partsLimit = (limits && typeof limits.parts === 'number'
+                        ? limits.parts
+                        : Infinity);
+
+    let parts = -1; // Account for initial boundary
+    let fields = 0;
+    let files = 0;
+    let skipPart = false;
+
+    this._fileEndsLeft = 0;
+    this._fileStream = undefined;
+    this._complete = false;
+    let fileSize = 0;
+
+    let field;
+    let fieldSize = 0;
+    let partCharset;
+    let partEncoding;
+    let partType;
+    let partName;
+    let partTruncated = false;
+
+    let hitFilesLimit = false;
+    let hitFieldsLimit = false;
+
+    this._hparser = null;
+    const hparser = new HeaderParser((header) => {
+      this._hparser = null;
+      skipPart = false;
+
+      partType = 'text/plain';
+      partCharset = defCharset;
+      partEncoding = '7bit';
+      partName = undefined;
+      partTruncated = false;
+
+      let filename;
+      if (!header['content-disposition']) {
+        skipPart = true;
+        return;
+      }
+
+      const disp = parseDisposition(header['content-disposition'][0],
+                                    paramDecoder);
+      if (!disp || disp.type !== 'form-data') {
+        skipPart = true;
+        return;
+      }
+
+      if (disp.params) {
+        if (disp.params.name)
+          partName = disp.params.name;
+
+        if (disp.params['filename*'])
+          filename = disp.params['filename*'];
+        else if (disp.params.filename)
+          filename = disp.params.filename;
+
+        if (filename !== undefined && !preservePath)
+          filename = basename(filename);
+      }
+
+      if (header['content-type']) {
+        const conType = parseContentType(header['content-type'][0]);
+        if (conType) {
+          partType = `${conType.type}/${conType.subtype}`;
+          if (conType.params && typeof conType.params.charset === 'string')
+            partCharset = conType.params.charset.toLowerCase();
+        }
+      }
+
+      if (header['content-transfer-encoding'])
+        partEncoding = header['content-transfer-encoding'][0].toLowerCase();
+
+      if (partType === 'application/octet-stream' || filename !== undefined) {
+        // File
+
+        if (files === filesLimit) {
+          if (!hitFilesLimit) {
+            hitFilesLimit = true;
+            this.emit('filesLimit');
+          }
+          skipPart = true;
+          return;
+        }
+        ++files;
+
+        if (this.listenerCount('file') === 0) {
+          skipPart = true;
+          return;
+        }
+
+        fileSize = 0;
+        this._fileStream = new FileStream(fileOpts, this);
+        ++this._fileEndsLeft;
+        this.emit(
+          'file',
+          partName,
+          this._fileStream,
+          { filename,
+            encoding: partEncoding,
+            mimeType: partType }
+        );
+      } else {
+        // Non-file
+
+        if (fields === fieldsLimit) {
+          if (!hitFieldsLimit) {
+            hitFieldsLimit = true;
+            this.emit('fieldsLimit');
+          }
+          skipPart = true;
+          return;
+        }
+        ++fields;
+
+        if (this.listenerCount('field') === 0) {
+          skipPart = true;
+          return;
+        }
+
+        field = [];
+        fieldSize = 0;
+      }
+    });
+
+    let matchPostBoundary = 0;
+    const ssCb = (isMatch, data, start, end, isDataSafe) => {
+retrydata:
+      while (data) {
+        if (this._hparser !== null) {
+          const ret = this._hparser.push(data, start, end);
+          if (ret === -1) {
+            this._hparser = null;
+            hparser.reset();
+            this.emit('error', new Error('Malformed part header'));
+            break;
+          }
+          start = ret;
+        }
+
+        if (start === end)
+          break;
+
+        if (matchPostBoundary !== 0) {
+          if (matchPostBoundary === 1) {
+            switch (data[start]) {
+              case 45: // '-'
+                // Try matching '--' after boundary
+                matchPostBoundary = 2;
+                ++start;
+                break;
+              case 13: // '\r'
+                // Try matching CR LF before header
+                matchPostBoundary = 3;
+                ++start;
+                break;
+              default:
+                matchPostBoundary = 0;
+            }
+            if (start === end)
+              return;
+          }
+
+          if (matchPostBoundary === 2) {
+            matchPostBoundary = 0;
+            if (data[start] === 45/* '-' */) {
+              // End of multipart data
+              this._complete = true;
+              this._bparser = ignoreData;
+              return;
+            }
+            // We saw something other than '-', so put the dash we consumed
+            // "back"
+            const writecb = this._writecb;
+            this._writecb = noop;
+            ssCb(false, BUF_DASH, 0, 1, false);
+            this._writecb = writecb;
+          } else if (matchPostBoundary === 3) {
+            matchPostBoundary = 0;
+            if (data[start] === 10/* '\n' */) {
+              ++start;
+              if (parts >= partsLimit)
+                break;
+              // Prepare the header parser
+              this._hparser = hparser;
+              if (start === end)
+                break;
+              // Process the remaining data as a header
+              continue retrydata;
+            } else {
+              // We saw something other than LF, so put the CR we consumed
+              // "back"
+              const writecb = this._writecb;
+              this._writecb = noop;
+              ssCb(false, BUF_CR, 0, 1, false);
+              this._writecb = writecb;
+            }
+          }
+        }
+
+        if (!skipPart) {
+          if (this._fileStream) {
+            let chunk;
+            const actualLen = Math.min(end - start, fileSizeLimit - fileSize);
+            if (!isDataSafe) {
+              chunk = Buffer.allocUnsafe(actualLen);
+              data.copy(chunk, 0, start, start + actualLen);
+            } else {
+              chunk = data.slice(start, start + actualLen);
+            }
+
+            fileSize += chunk.length;
+            if (fileSize === fileSizeLimit) {
+              if (chunk.length > 0)
+                this._fileStream.push(chunk);
+              this._fileStream.emit('limit');
+              this._fileStream.truncated = true;
+              skipPart = true;
+            } else if (!this._fileStream.push(chunk)) {
+              if (this._writecb)
+                this._fileStream._readcb = this._writecb;
+              this._writecb = null;
+            }
+          } else if (field !== undefined) {
+            let chunk;
+            const actualLen = Math.min(
+              end - start,
+              fieldSizeLimit - fieldSize
+            );
+            if (!isDataSafe) {
+              chunk = Buffer.allocUnsafe(actualLen);
+              data.copy(chunk, 0, start, start + actualLen);
+            } else {
+              chunk = data.slice(start, start + actualLen);
+            }
+
+            fieldSize += actualLen;
+            field.push(chunk);
+            if (fieldSize === fieldSizeLimit) {
+              skipPart = true;
+              partTruncated = true;
+            }
+          }
+        }
+
+        break;
+      }
+
+      if (isMatch) {
+        matchPostBoundary = 1;
+
+        if (this._fileStream) {
+          // End the active file stream if the previous part was a file
+          this._fileStream.push(null);
+          this._fileStream = null;
+        } else if (field !== undefined) {
+          let data;
+          switch (field.length) {
+            case 0:
+              data = '';
+              break;
+            case 1:
+              data = convertToUTF8(field[0], partCharset, 0);
+              break;
+            default:
+              data = convertToUTF8(
+                Buffer.concat(field, fieldSize),
+                partCharset,
+                0
+              );
+          }
+          field = undefined;
+          fieldSize = 0;
+          this.emit(
+            'field',
+            partName,
+            data,
+            { nameTruncated: false,
+              valueTruncated: partTruncated,
+              encoding: partEncoding,
+              mimeType: partType }
+          );
+        }
+
+        if (++parts === partsLimit)
+          this.emit('partsLimit');
+      }
+    };
+    this._bparser = new StreamSearch(`\r\n--${boundary}`, ssCb);
+
+    this._writecb = null;
+    this._finalcb = null;
+
+    // Just in case there is no preamble
+    this.write(BUF_CRLF);
+  }
+
+  static detect(conType) {
+    return (conType.type === 'multipart' && conType.subtype === 'form-data');
+  }
+
+  _write(chunk, enc, cb) {
+    this._writecb = cb;
+    this._bparser.push(chunk, 0);
+    if (this._writecb)
+      callAndUnsetCb(this);
+  }
+
+  _destroy(err, cb) {
+    this._hparser = null;
+    this._bparser = ignoreData;
+    if (!err)
+      err = checkEndState(this);
+    const fileStream = this._fileStream;
+    if (fileStream) {
+      this._fileStream = null;
+      fileStream.destroy(err);
+    }
+    cb(err);
+  }
+
+  _final(cb) {
+    this._bparser.destroy();
+    if (!this._complete)
+      return cb(new Error('Unexpected end of form'));
+    if (this._fileEndsLeft)
+      this._finalcb = finalcb.bind(null, this, cb);
+    else
+      finalcb(this, cb);
+  }
+}
+
+function finalcb(self, cb, err) {
+  if (err)
+    return cb(err);
+  err = checkEndState(self);
+  cb(err);
+}
+
+function checkEndState(self) {
+  if (self._hparser)
+    return new Error('Malformed part header');
+  const fileStream = self._fileStream;
+  if (fileStream) {
+    self._fileStream = null;
+    fileStream.destroy(new Error('Unexpected end of file'));
+  }
+  if (!self._complete)
+    return new Error('Unexpected end of form');
+}
+
+const TOKEN = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
+  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+];
+
+const FIELD_VCHAR = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+];
+
+module.exports = Multipart;
diff --git a/server/node_modules/busboy/lib/types/urlencoded.js b/server/node_modules/busboy/lib/types/urlencoded.js
new file mode 100644
index 0000000..5c463a2
--- /dev/null
+++ b/server/node_modules/busboy/lib/types/urlencoded.js
@@ -0,0 +1,350 @@
+'use strict';
+
+const { Writable } = require('stream');
+
+const { getDecoder } = require('../utils.js');
+
+class URLEncoded extends Writable {
+  constructor(cfg) {
+    const streamOpts = {
+      autoDestroy: true,
+      emitClose: true,
+      highWaterMark: (typeof cfg.highWaterMark === 'number'
+                      ? cfg.highWaterMark
+                      : undefined),
+    };
+    super(streamOpts);
+
+    let charset = (cfg.defCharset || 'utf8');
+    if (cfg.conType.params && typeof cfg.conType.params.charset === 'string')
+      charset = cfg.conType.params.charset;
+
+    this.charset = charset;
+
+    const limits = cfg.limits;
+    this.fieldSizeLimit = (limits && typeof limits.fieldSize === 'number'
+                           ? limits.fieldSize
+                           : 1 * 1024 * 1024);
+    this.fieldsLimit = (limits && typeof limits.fields === 'number'
+                        ? limits.fields
+                        : Infinity);
+    this.fieldNameSizeLimit = (
+      limits && typeof limits.fieldNameSize === 'number'
+      ? limits.fieldNameSize
+      : 100
+    );
+
+    this._inKey = true;
+    this._keyTrunc = false;
+    this._valTrunc = false;
+    this._bytesKey = 0;
+    this._bytesVal = 0;
+    this._fields = 0;
+    this._key = '';
+    this._val = '';
+    this._byte = -2;
+    this._lastPos = 0;
+    this._encode = 0;
+    this._decoder = getDecoder(charset);
+  }
+
+  static detect(conType) {
+    return (conType.type === 'application'
+            && conType.subtype === 'x-www-form-urlencoded');
+  }
+
+  _write(chunk, enc, cb) {
+    if (this._fields >= this.fieldsLimit)
+      return cb();
+
+    let i = 0;
+    const len = chunk.length;
+    this._lastPos = 0;
+
+    // Check if we last ended mid-percent-encoded byte
+    if (this._byte !== -2) {
+      i = readPctEnc(this, chunk, i, len);
+      if (i === -1)
+        return cb(new Error('Malformed urlencoded form'));
+      if (i >= len)
+        return cb();
+      if (this._inKey)
+        ++this._bytesKey;
+      else
+        ++this._bytesVal;
+    }
+
+main:
+    while (i < len) {
+      if (this._inKey) {
+        // Parsing key
+
+        i = skipKeyBytes(this, chunk, i, len);
+
+        while (i < len) {
+          switch (chunk[i]) {
+            case 61: // '='
+              if (this._lastPos < i)
+                this._key += chunk.latin1Slice(this._lastPos, i);
+              this._lastPos = ++i;
+              this._key = this._decoder(this._key, this._encode);
+              this._encode = 0;
+              this._inKey = false;
+              continue main;
+            case 38: // '&'
+              if (this._lastPos < i)
+                this._key += chunk.latin1Slice(this._lastPos, i);
+              this._lastPos = ++i;
+              this._key = this._decoder(this._key, this._encode);
+              this._encode = 0;
+              if (this._bytesKey > 0) {
+                this.emit(
+                  'field',
+                  this._key,
+                  '',
+                  { nameTruncated: this._keyTrunc,
+                    valueTruncated: false,
+                    encoding: this.charset,
+                    mimeType: 'text/plain' }
+                );
+              }
+              this._key = '';
+              this._val = '';
+              this._keyTrunc = false;
+              this._valTrunc = false;
+              this._bytesKey = 0;
+              this._bytesVal = 0;
+              if (++this._fields >= this.fieldsLimit) {
+                this.emit('fieldsLimit');
+                return cb();
+              }
+              continue;
+            case 43: // '+'
+              if (this._lastPos < i)
+                this._key += chunk.latin1Slice(this._lastPos, i);
+              this._key += ' ';
+              this._lastPos = i + 1;
+              break;
+            case 37: // '%'
+              if (this._encode === 0)
+                this._encode = 1;
+              if (this._lastPos < i)
+                this._key += chunk.latin1Slice(this._lastPos, i);
+              this._lastPos = i + 1;
+              this._byte = -1;
+              i = readPctEnc(this, chunk, i + 1, len);
+              if (i === -1)
+                return cb(new Error('Malformed urlencoded form'));
+              if (i >= len)
+                return cb();
+              ++this._bytesKey;
+              i = skipKeyBytes(this, chunk, i, len);
+              continue;
+          }
+          ++i;
+          ++this._bytesKey;
+          i = skipKeyBytes(this, chunk, i, len);
+        }
+        if (this._lastPos < i)
+          this._key += chunk.latin1Slice(this._lastPos, i);
+      } else {
+        // Parsing value
+
+        i = skipValBytes(this, chunk, i, len);
+
+        while (i < len) {
+          switch (chunk[i]) {
+            case 38: // '&'
+              if (this._lastPos < i)
+                this._val += chunk.latin1Slice(this._lastPos, i);
+              this._lastPos = ++i;
+              this._inKey = true;
+              this._val = this._decoder(this._val, this._encode);
+              this._encode = 0;
+              if (this._bytesKey > 0 || this._bytesVal > 0) {
+                this.emit(
+                  'field',
+                  this._key,
+                  this._val,
+                  { nameTruncated: this._keyTrunc,
+                    valueTruncated: this._valTrunc,
+                    encoding: this.charset,
+                    mimeType: 'text/plain' }
+                );
+              }
+              this._key = '';
+              this._val = '';
+              this._keyTrunc = false;
+              this._valTrunc = false;
+              this._bytesKey = 0;
+              this._bytesVal = 0;
+              if (++this._fields >= this.fieldsLimit) {
+                this.emit('fieldsLimit');
+                return cb();
+              }
+              continue main;
+            case 43: // '+'
+              if (this._lastPos < i)
+                this._val += chunk.latin1Slice(this._lastPos, i);
+              this._val += ' ';
+              this._lastPos = i + 1;
+              break;
+            case 37: // '%'
+              if (this._encode === 0)
+                this._encode = 1;
+              if (this._lastPos < i)
+                this._val += chunk.latin1Slice(this._lastPos, i);
+              this._lastPos = i + 1;
+              this._byte = -1;
+              i = readPctEnc(this, chunk, i + 1, len);
+              if (i === -1)
+                return cb(new Error('Malformed urlencoded form'));
+              if (i >= len)
+                return cb();
+              ++this._bytesVal;
+              i = skipValBytes(this, chunk, i, len);
+              continue;
+          }
+          ++i;
+          ++this._bytesVal;
+          i = skipValBytes(this, chunk, i, len);
+        }
+        if (this._lastPos < i)
+          this._val += chunk.latin1Slice(this._lastPos, i);
+      }
+    }
+
+    cb();
+  }
+
+  _final(cb) {
+    if (this._byte !== -2)
+      return cb(new Error('Malformed urlencoded form'));
+    if (!this._inKey || this._bytesKey > 0 || this._bytesVal > 0) {
+      if (this._inKey)
+        this._key = this._decoder(this._key, this._encode);
+      else
+        this._val = this._decoder(this._val, this._encode);
+      this.emit(
+        'field',
+        this._key,
+        this._val,
+        { nameTruncated: this._keyTrunc,
+          valueTruncated: this._valTrunc,
+          encoding: this.charset,
+          mimeType: 'text/plain' }
+      );
+    }
+    cb();
+  }
+}
+
+function readPctEnc(self, chunk, pos, len) {
+  if (pos >= len)
+    return len;
+
+  if (self._byte === -1) {
+    // We saw a '%' but no hex characters yet
+    const hexUpper = HEX_VALUES[chunk[pos++]];
+    if (hexUpper === -1)
+      return -1;
+
+    if (hexUpper >= 8)
+      self._encode = 2; // Indicate high bits detected
+
+    if (pos < len) {
+      // Both hex characters are in this chunk
+      const hexLower = HEX_VALUES[chunk[pos++]];
+      if (hexLower === -1)
+        return -1;
+
+      if (self._inKey)
+        self._key += String.fromCharCode((hexUpper << 4) + hexLower);
+      else
+        self._val += String.fromCharCode((hexUpper << 4) + hexLower);
+
+      self._byte = -2;
+      self._lastPos = pos;
+    } else {
+      // Only one hex character was available in this chunk
+      self._byte = hexUpper;
+    }
+  } else {
+    // We saw only one hex character so far
+    const hexLower = HEX_VALUES[chunk[pos++]];
+    if (hexLower === -1)
+      return -1;
+
+    if (self._inKey)
+      self._key += String.fromCharCode((self._byte << 4) + hexLower);
+    else
+      self._val += String.fromCharCode((self._byte << 4) + hexLower);
+
+    self._byte = -2;
+    self._lastPos = pos;
+  }
+
+  return pos;
+}
+
+function skipKeyBytes(self, chunk, pos, len) {
+  // Skip bytes if we've truncated
+  if (self._bytesKey > self.fieldNameSizeLimit) {
+    if (!self._keyTrunc) {
+      if (self._lastPos < pos)
+        self._key += chunk.latin1Slice(self._lastPos, pos - 1);
+    }
+    self._keyTrunc = true;
+    for (; pos < len; ++pos) {
+      const code = chunk[pos];
+      if (code === 61/* '=' */ || code === 38/* '&' */)
+        break;
+      ++self._bytesKey;
+    }
+    self._lastPos = pos;
+  }
+
+  return pos;
+}
+
+function skipValBytes(self, chunk, pos, len) {
+  // Skip bytes if we've truncated
+  if (self._bytesVal > self.fieldSizeLimit) {
+    if (!self._valTrunc) {
+      if (self._lastPos < pos)
+        self._val += chunk.latin1Slice(self._lastPos, pos - 1);
+    }
+    self._valTrunc = true;
+    for (; pos < len; ++pos) {
+      if (chunk[pos] === 38/* '&' */)
+        break;
+      ++self._bytesVal;
+    }
+    self._lastPos = pos;
+  }
+
+  return pos;
+}
+
+/* eslint-disable no-multi-spaces */
+const HEX_VALUES = [
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+   0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
+  -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+];
+/* eslint-enable no-multi-spaces */
+
+module.exports = URLEncoded;
diff --git a/server/node_modules/busboy/lib/utils.js b/server/node_modules/busboy/lib/utils.js
new file mode 100644
index 0000000..8274f6c
--- /dev/null
+++ b/server/node_modules/busboy/lib/utils.js
@@ -0,0 +1,596 @@
+'use strict';
+
+function parseContentType(str) {
+  if (str.length === 0)
+    return;
+
+  const params = Object.create(null);
+  let i = 0;
+
+  // Parse type
+  for (; i < str.length; ++i) {
+    const code = str.charCodeAt(i);
+    if (TOKEN[code] !== 1) {
+      if (code !== 47/* '/' */ || i === 0)
+        return;
+      break;
+    }
+  }
+  // Check for type without subtype
+  if (i === str.length)
+    return;
+
+  const type = str.slice(0, i).toLowerCase();
+
+  // Parse subtype
+  const subtypeStart = ++i;
+  for (; i < str.length; ++i) {
+    const code = str.charCodeAt(i);
+    if (TOKEN[code] !== 1) {
+      // Make sure we have a subtype
+      if (i === subtypeStart)
+        return;
+
+      if (parseContentTypeParams(str, i, params) === undefined)
+        return;
+      break;
+    }
+  }
+  // Make sure we have a subtype
+  if (i === subtypeStart)
+    return;
+
+  const subtype = str.slice(subtypeStart, i).toLowerCase();
+
+  return { type, subtype, params };
+}
+
+function parseContentTypeParams(str, i, params) {
+  while (i < str.length) {
+    // Consume whitespace
+    for (; i < str.length; ++i) {
+      const code = str.charCodeAt(i);
+      if (code !== 32/* ' ' */ && code !== 9/* '\t' */)
+        break;
+    }
+
+    // Ended on whitespace
+    if (i === str.length)
+      break;
+
+    // Check for malformed parameter
+    if (str.charCodeAt(i++) !== 59/* ';' */)
+      return;
+
+    // Consume whitespace
+    for (; i < str.length; ++i) {
+      const code = str.charCodeAt(i);
+      if (code !== 32/* ' ' */ && code !== 9/* '\t' */)
+        break;
+    }
+
+    // Ended on whitespace (malformed)
+    if (i === str.length)
+      return;
+
+    let name;
+    const nameStart = i;
+    // Parse parameter name
+    for (; i < str.length; ++i) {
+      const code = str.charCodeAt(i);
+      if (TOKEN[code] !== 1) {
+        if (code !== 61/* '=' */)
+          return;
+        break;
+      }
+    }
+
+    // No value (malformed)
+    if (i === str.length)
+      return;
+
+    name = str.slice(nameStart, i);
+    ++i; // Skip over '='
+
+    // No value (malformed)
+    if (i === str.length)
+      return;
+
+    let value = '';
+    let valueStart;
+    if (str.charCodeAt(i) === 34/* '"' */) {
+      valueStart = ++i;
+      let escaping = false;
+      // Parse quoted value
+      for (; i < str.length; ++i) {
+        const code = str.charCodeAt(i);
+        if (code === 92/* '\\' */) {
+          if (escaping) {
+            valueStart = i;
+            escaping = false;
+          } else {
+            value += str.slice(valueStart, i);
+            escaping = true;
+          }
+          continue;
+        }
+        if (code === 34/* '"' */) {
+          if (escaping) {
+            valueStart = i;
+            escaping = false;
+            continue;
+          }
+          value += str.slice(valueStart, i);
+          break;
+        }
+        if (escaping) {
+          valueStart = i - 1;
+          escaping = false;
+        }
+        // Invalid unescaped quoted character (malformed)
+        if (QDTEXT[code] !== 1)
+          return;
+      }
+
+      // No end quote (malformed)
+      if (i === str.length)
+        return;
+
+      ++i; // Skip over double quote
+    } else {
+      valueStart = i;
+      // Parse unquoted value
+      for (; i < str.length; ++i) {
+        const code = str.charCodeAt(i);
+        if (TOKEN[code] !== 1) {
+          // No value (malformed)
+          if (i === valueStart)
+            return;
+          break;
+        }
+      }
+      value = str.slice(valueStart, i);
+    }
+
+    name = name.toLowerCase();
+    if (params[name] === undefined)
+      params[name] = value;
+  }
+
+  return params;
+}
+
+function parseDisposition(str, defDecoder) {
+  if (str.length === 0)
+    return;
+
+  const params = Object.create(null);
+  let i = 0;
+
+  for (; i < str.length; ++i) {
+    const code = str.charCodeAt(i);
+    if (TOKEN[code] !== 1) {
+      if (parseDispositionParams(str, i, params, defDecoder) === undefined)
+        return;
+      break;
+    }
+  }
+
+  const type = str.slice(0, i).toLowerCase();
+
+  return { type, params };
+}
+
+function parseDispositionParams(str, i, params, defDecoder) {
+  while (i < str.length) {
+    // Consume whitespace
+    for (; i < str.length; ++i) {
+      const code = str.charCodeAt(i);
+      if (code !== 32/* ' ' */ && code !== 9/* '\t' */)
+        break;
+    }
+
+    // Ended on whitespace
+    if (i === str.length)
+      break;
+
+    // Check for malformed parameter
+    if (str.charCodeAt(i++) !== 59/* ';' */)
+      return;
+
+    // Consume whitespace
+    for (; i < str.length; ++i) {
+      const code = str.charCodeAt(i);
+      if (code !== 32/* ' ' */ && code !== 9/* '\t' */)
+        break;
+    }
+
+    // Ended on whitespace (malformed)
+    if (i === str.length)
+      return;
+
+    let name;
+    const nameStart = i;
+    // Parse parameter name
+    for (; i < str.length; ++i) {
+      const code = str.charCodeAt(i);
+      if (TOKEN[code] !== 1) {
+        if (code === 61/* '=' */)
+          break;
+        return;
+      }
+    }
+
+    // No value (malformed)
+    if (i === str.length)
+      return;
+
+    let value = '';
+    let valueStart;
+    let charset;
+    //~ let lang;
+    name = str.slice(nameStart, i);
+    if (name.charCodeAt(name.length - 1) === 42/* '*' */) {
+      // Extended value
+
+      const charsetStart = ++i;
+      // Parse charset name
+      for (; i < str.length; ++i) {
+        const code = str.charCodeAt(i);
+        if (CHARSET[code] !== 1) {
+          if (code !== 39/* '\'' */)
+            return;
+          break;
+        }
+      }
+
+      // Incomplete charset (malformed)
+      if (i === str.length)
+        return;
+
+      charset = str.slice(charsetStart, i);
+      ++i; // Skip over the '\''
+
+      //~ const langStart = ++i;
+      // Parse language name
+      for (; i < str.length; ++i) {
+        const code = str.charCodeAt(i);
+        if (code === 39/* '\'' */)
+          break;
+      }
+
+      // Incomplete language (malformed)
+      if (i === str.length)
+        return;
+
+      //~ lang = str.slice(langStart, i);
+      ++i; // Skip over the '\''
+
+      // No value (malformed)
+      if (i === str.length)
+        return;
+
+      valueStart = i;
+
+      let encode = 0;
+      // Parse value
+      for (; i < str.length; ++i) {
+        const code = str.charCodeAt(i);
+        if (EXTENDED_VALUE[code] !== 1) {
+          if (code === 37/* '%' */) {
+            let hexUpper;
+            let hexLower;
+            if (i + 2 < str.length
+                && (hexUpper = HEX_VALUES[str.charCodeAt(i + 1)]) !== -1
+                && (hexLower = HEX_VALUES[str.charCodeAt(i + 2)]) !== -1) {
+              const byteVal = (hexUpper << 4) + hexLower;
+              value += str.slice(valueStart, i);
+              value += String.fromCharCode(byteVal);
+              i += 2;
+              valueStart = i + 1;
+              if (byteVal >= 128)
+                encode = 2;
+              else if (encode === 0)
+                encode = 1;
+              continue;
+            }
+            // '%' disallowed in non-percent encoded contexts (malformed)
+            return;
+          }
+          break;
+        }
+      }
+
+      value += str.slice(valueStart, i);
+      value = convertToUTF8(value, charset, encode);
+      if (value === undefined)
+        return;
+    } else {
+      // Non-extended value
+
+      ++i; // Skip over '='
+
+      // No value (malformed)
+      if (i === str.length)
+        return;
+
+      if (str.charCodeAt(i) === 34/* '"' */) {
+        valueStart = ++i;
+        let escaping = false;
+        // Parse quoted value
+        for (; i < str.length; ++i) {
+          const code = str.charCodeAt(i);
+          if (code === 92/* '\\' */) {
+            if (escaping) {
+              valueStart = i;
+              escaping = false;
+            } else {
+              value += str.slice(valueStart, i);
+              escaping = true;
+            }
+            continue;
+          }
+          if (code === 34/* '"' */) {
+            if (escaping) {
+              valueStart = i;
+              escaping = false;
+              continue;
+            }
+            value += str.slice(valueStart, i);
+            break;
+          }
+          if (escaping) {
+            valueStart = i - 1;
+            escaping = false;
+          }
+          // Invalid unescaped quoted character (malformed)
+          if (QDTEXT[code] !== 1)
+            return;
+        }
+
+        // No end quote (malformed)
+        if (i === str.length)
+          return;
+
+        ++i; // Skip over double quote
+      } else {
+        valueStart = i;
+        // Parse unquoted value
+        for (; i < str.length; ++i) {
+          const code = str.charCodeAt(i);
+          if (TOKEN[code] !== 1) {
+            // No value (malformed)
+            if (i === valueStart)
+              return;
+            break;
+          }
+        }
+        value = str.slice(valueStart, i);
+      }
+
+      value = defDecoder(value, 2);
+      if (value === undefined)
+        return;
+    }
+
+    name = name.toLowerCase();
+    if (params[name] === undefined)
+      params[name] = value;
+  }
+
+  return params;
+}
+
+function getDecoder(charset) {
+  let lc;
+  while (true) {
+    switch (charset) {
+      case 'utf-8':
+      case 'utf8':
+        return decoders.utf8;
+      case 'latin1':
+      case 'ascii': // TODO: Make these a separate, strict decoder?
+      case 'us-ascii':
+      case 'iso-8859-1':
+      case 'iso8859-1':
+      case 'iso88591':
+      case 'iso_8859-1':
+      case 'windows-1252':
+      case 'iso_8859-1:1987':
+      case 'cp1252':
+      case 'x-cp1252':
+        return decoders.latin1;
+      case 'utf16le':
+      case 'utf-16le':
+      case 'ucs2':
+      case 'ucs-2':
+        return decoders.utf16le;
+      case 'base64':
+        return decoders.base64;
+      default:
+        if (lc === undefined) {
+          lc = true;
+          charset = charset.toLowerCase();
+          continue;
+        }
+        return decoders.other.bind(charset);
+    }
+  }
+}
+
+const decoders = {
+  utf8: (data, hint) => {
+    if (data.length === 0)
+      return '';
+    if (typeof data === 'string') {
+      // If `data` never had any percent-encoded bytes or never had any that
+      // were outside of the ASCII range, then we can safely just return the
+      // input since UTF-8 is ASCII compatible
+      if (hint < 2)
+        return data;
+
+      data = Buffer.from(data, 'latin1');
+    }
+    return data.utf8Slice(0, data.length);
+  },
+
+  latin1: (data, hint) => {
+    if (data.length === 0)
+      return '';
+    if (typeof data === 'string')
+      return data;
+    return data.latin1Slice(0, data.length);
+  },
+
+  utf16le: (data, hint) => {
+    if (data.length === 0)
+      return '';
+    if (typeof data === 'string')
+      data = Buffer.from(data, 'latin1');
+    return data.ucs2Slice(0, data.length);
+  },
+
+  base64: (data, hint) => {
+    if (data.length === 0)
+      return '';
+    if (typeof data === 'string')
+      data = Buffer.from(data, 'latin1');
+    return data.base64Slice(0, data.length);
+  },
+
+  other: (data, hint) => {
+    if (data.length === 0)
+      return '';
+    if (typeof data === 'string')
+      data = Buffer.from(data, 'latin1');
+    try {
+      const decoder = new TextDecoder(this);
+      return decoder.decode(data);
+    } catch {}
+  },
+};
+
+function convertToUTF8(data, charset, hint) {
+  const decode = getDecoder(charset);
+  if (decode)
+    return decode(data, hint);
+}
+
+function basename(path) {
+  if (typeof path !== 'string')
+    return '';
+  for (let i = path.length - 1; i >= 0; --i) {
+    switch (path.charCodeAt(i)) {
+      case 0x2F: // '/'
+      case 0x5C: // '\'
+        path = path.slice(i + 1);
+        return (path === '..' || path === '.' ? '' : path);
+    }
+  }
+  return (path === '..' || path === '.' ? '' : path);
+}
+
+const TOKEN = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
+  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+];
+
+const QDTEXT = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+];
+
+const CHARSET = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
+  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+];
+
+const EXTENDED_VALUE = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 0,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
+  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+];
+
+/* eslint-disable no-multi-spaces */
+const HEX_VALUES = [
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+   0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
+  -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+];
+/* eslint-enable no-multi-spaces */
+
+module.exports = {
+  basename,
+  convertToUTF8,
+  getDecoder,
+  parseContentType,
+  parseDisposition,
+};
diff --git a/server/node_modules/busboy/package.json b/server/node_modules/busboy/package.json
new file mode 100644
index 0000000..ac2577f
--- /dev/null
+++ b/server/node_modules/busboy/package.json
@@ -0,0 +1,22 @@
+{ "name": "busboy",
+  "version": "1.6.0",
+  "author": "Brian White <mscdex@mscdex.net>",
+  "description": "A streaming parser for HTML form data for node.js",
+  "main": "./lib/index.js",
+  "dependencies": {
+    "streamsearch": "^1.1.0"
+  },
+  "devDependencies": {
+    "@mscdex/eslint-config": "^1.1.0",
+    "eslint": "^7.32.0"
+  },
+  "scripts": {
+    "test": "node test/test.js",
+    "lint": "eslint --cache --report-unused-disable-directives --ext=.js .eslintrc.js lib test bench",
+    "lint:fix": "npm run lint -- --fix"
+  },
+  "engines": { "node": ">=10.16.0" },
+  "keywords": [ "uploads", "forms", "multipart", "form-data" ],
+  "licenses": [ { "type": "MIT", "url": "http://github.com/mscdex/busboy/raw/master/LICENSE" } ],
+  "repository": { "type": "git", "url": "http://github.com/mscdex/busboy.git" }
+}
diff --git a/server/node_modules/busboy/test/common.js b/server/node_modules/busboy/test/common.js
new file mode 100644
index 0000000..fb82ad8
--- /dev/null
+++ b/server/node_modules/busboy/test/common.js
@@ -0,0 +1,109 @@
+'use strict';
+
+const assert = require('assert');
+const { inspect } = require('util');
+
+const mustCallChecks = [];
+
+function noop() {}
+
+function runCallChecks(exitCode) {
+  if (exitCode !== 0) return;
+
+  const failed = mustCallChecks.filter((context) => {
+    if ('minimum' in context) {
+      context.messageSegment = `at least ${context.minimum}`;
+      return context.actual < context.minimum;
+    }
+    context.messageSegment = `exactly ${context.exact}`;
+    return context.actual !== context.exact;
+  });
+
+  failed.forEach((context) => {
+    console.error('Mismatched %s function calls. Expected %s, actual %d.',
+                  context.name,
+                  context.messageSegment,
+                  context.actual);
+    console.error(context.stack.split('\n').slice(2).join('\n'));
+  });
+
+  if (failed.length)
+    process.exit(1);
+}
+
+function mustCall(fn, exact) {
+  return _mustCallInner(fn, exact, 'exact');
+}
+
+function mustCallAtLeast(fn, minimum) {
+  return _mustCallInner(fn, minimum, 'minimum');
+}
+
+function _mustCallInner(fn, criteria = 1, field) {
+  if (process._exiting)
+    throw new Error('Cannot use common.mustCall*() in process exit handler');
+
+  if (typeof fn === 'number') {
+    criteria = fn;
+    fn = noop;
+  } else if (fn === undefined) {
+    fn = noop;
+  }
+
+  if (typeof criteria !== 'number')
+    throw new TypeError(`Invalid ${field} value: ${criteria}`);
+
+  const context = {
+    [field]: criteria,
+    actual: 0,
+    stack: inspect(new Error()),
+    name: fn.name || '<anonymous>'
+  };
+
+  // Add the exit listener only once to avoid listener leak warnings
+  if (mustCallChecks.length === 0)
+    process.on('exit', runCallChecks);
+
+  mustCallChecks.push(context);
+
+  function wrapped(...args) {
+    ++context.actual;
+    return fn.call(this, ...args);
+  }
+  // TODO: remove origFn?
+  wrapped.origFn = fn;
+
+  return wrapped;
+}
+
+function getCallSite(top) {
+  const originalStackFormatter = Error.prepareStackTrace;
+  Error.prepareStackTrace = (err, stack) =>
+    `${stack[0].getFileName()}:${stack[0].getLineNumber()}`;
+  const err = new Error();
+  Error.captureStackTrace(err, top);
+  // With the V8 Error API, the stack is not formatted until it is accessed
+  // eslint-disable-next-line no-unused-expressions
+  err.stack;
+  Error.prepareStackTrace = originalStackFormatter;
+  return err.stack;
+}
+
+function mustNotCall(msg) {
+  const callSite = getCallSite(mustNotCall);
+  return function mustNotCall(...args) {
+    args = args.map(inspect).join(', ');
+    const argsInfo = (args.length > 0
+                      ? `\ncalled with arguments: ${args}`
+                      : '');
+    assert.fail(
+      `${msg || 'function should not have been called'} at ${callSite}`
+        + argsInfo);
+  };
+}
+
+module.exports = {
+  mustCall,
+  mustCallAtLeast,
+  mustNotCall,
+};
diff --git a/server/node_modules/busboy/test/test-types-multipart-charsets.js b/server/node_modules/busboy/test/test-types-multipart-charsets.js
new file mode 100644
index 0000000..ed9c38a
--- /dev/null
+++ b/server/node_modules/busboy/test/test-types-multipart-charsets.js
@@ -0,0 +1,94 @@
+'use strict';
+
+const assert = require('assert');
+const { inspect } = require('util');
+
+const { mustCall } = require(`${__dirname}/common.js`);
+
+const busboy = require('..');
+
+const input = Buffer.from([
+  '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+ 'Content-Disposition: form-data; '
+   + 'name="upload_file_0"; filename="テスト.dat"',
+ 'Content-Type: application/octet-stream',
+ '',
+ 'A'.repeat(1023),
+ '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--'
+].join('\r\n'));
+const boundary = '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k';
+const expected = [
+  { type: 'file',
+    name: 'upload_file_0',
+    data: Buffer.from('A'.repeat(1023)),
+    info: {
+      filename: 'テスト.dat',
+      encoding: '7bit',
+      mimeType: 'application/octet-stream',
+    },
+    limited: false,
+  },
+];
+const bb = busboy({
+  defParamCharset: 'utf8',
+  headers: {
+    'content-type': `multipart/form-data; boundary=${boundary}`,
+  }
+});
+const results = [];
+
+bb.on('field', (name, val, info) => {
+  results.push({ type: 'field', name, val, info });
+});
+
+bb.on('file', (name, stream, info) => {
+  const data = [];
+  let nb = 0;
+  const file = {
+    type: 'file',
+    name,
+    data: null,
+    info,
+    limited: false,
+  };
+  results.push(file);
+  stream.on('data', (d) => {
+    data.push(d);
+    nb += d.length;
+  }).on('limit', () => {
+    file.limited = true;
+  }).on('close', () => {
+    file.data = Buffer.concat(data, nb);
+    assert.strictEqual(stream.truncated, file.limited);
+  }).once('error', (err) => {
+    file.err = err.message;
+  });
+});
+
+bb.on('error', (err) => {
+  results.push({ error: err.message });
+});
+
+bb.on('partsLimit', () => {
+  results.push('partsLimit');
+});
+
+bb.on('filesLimit', () => {
+  results.push('filesLimit');
+});
+
+bb.on('fieldsLimit', () => {
+  results.push('fieldsLimit');
+});
+
+bb.on('close', mustCall(() => {
+  assert.deepStrictEqual(
+    results,
+    expected,
+    'Results mismatch.\n'
+      + `Parsed: ${inspect(results)}\n`
+      + `Expected: ${inspect(expected)}`
+  );
+}));
+
+bb.end(input);
diff --git a/server/node_modules/busboy/test/test-types-multipart-stream-pause.js b/server/node_modules/busboy/test/test-types-multipart-stream-pause.js
new file mode 100644
index 0000000..df7268a
--- /dev/null
+++ b/server/node_modules/busboy/test/test-types-multipart-stream-pause.js
@@ -0,0 +1,102 @@
+'use strict';
+
+const assert = require('assert');
+const { randomFillSync } = require('crypto');
+const { inspect } = require('util');
+
+const busboy = require('..');
+
+const { mustCall } = require('./common.js');
+
+const BOUNDARY = 'u2KxIV5yF1y+xUspOQCCZopaVgeV6Jxihv35XQJmuTx8X3sh';
+
+function formDataSection(key, value) {
+  return Buffer.from(
+    `\r\n--${BOUNDARY}`
+      + `\r\nContent-Disposition: form-data; name="${key}"`
+      + `\r\n\r\n${value}`
+  );
+}
+
+function formDataFile(key, filename, contentType) {
+  const buf = Buffer.allocUnsafe(100000);
+  return Buffer.concat([
+    Buffer.from(`\r\n--${BOUNDARY}\r\n`),
+    Buffer.from(`Content-Disposition: form-data; name="${key}"`
+                  + `; filename="${filename}"\r\n`),
+    Buffer.from(`Content-Type: ${contentType}\r\n\r\n`),
+    randomFillSync(buf)
+  ]);
+}
+
+const reqChunks = [
+  Buffer.concat([
+    formDataFile('file', 'file.bin', 'application/octet-stream'),
+    formDataSection('foo', 'foo value'),
+  ]),
+  formDataSection('bar', 'bar value'),
+  Buffer.from(`\r\n--${BOUNDARY}--\r\n`)
+];
+const bb = busboy({
+  headers: {
+    'content-type': `multipart/form-data; boundary=${BOUNDARY}`
+  }
+});
+const expected = [
+  { type: 'file',
+    name: 'file',
+    info: {
+      filename: 'file.bin',
+      encoding: '7bit',
+      mimeType: 'application/octet-stream',
+    },
+  },
+  { type: 'field',
+    name: 'foo',
+    val: 'foo value',
+    info: {
+      nameTruncated: false,
+      valueTruncated: false,
+      encoding: '7bit',
+      mimeType: 'text/plain',
+    },
+  },
+  { type: 'field',
+    name: 'bar',
+    val: 'bar value',
+    info: {
+      nameTruncated: false,
+      valueTruncated: false,
+      encoding: '7bit',
+      mimeType: 'text/plain',
+    },
+  },
+];
+const results = [];
+
+bb.on('field', (name, val, info) => {
+  results.push({ type: 'field', name, val, info });
+});
+
+bb.on('file', (name, stream, info) => {
+  results.push({ type: 'file', name, info });
+  // Simulate a pipe where the destination is pausing (perhaps due to waiting
+  // for file system write to finish)
+  setTimeout(() => {
+    stream.resume();
+  }, 10);
+});
+
+bb.on('close', mustCall(() => {
+  assert.deepStrictEqual(
+    results,
+    expected,
+    'Results mismatch.\n'
+      + `Parsed: ${inspect(results)}\n`
+      + `Expected: ${inspect(expected)}`
+  );
+}));
+
+for (const chunk of reqChunks)
+  bb.write(chunk);
+bb.end();
diff --git a/server/node_modules/busboy/test/test-types-multipart.js b/server/node_modules/busboy/test/test-types-multipart.js
new file mode 100644
index 0000000..9755642
--- /dev/null
+++ b/server/node_modules/busboy/test/test-types-multipart.js
@@ -0,0 +1,1053 @@
+'use strict';
+
+const assert = require('assert');
+const { inspect } = require('util');
+
+const busboy = require('..');
+
+const active = new Map();
+
+const tests = [
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_0"',
+       '',
+       'super alpha file',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_1"',
+       '',
+       'super beta file',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="1k_a.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'A'.repeat(1023),
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_1"; filename="1k_b.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'B'.repeat(1023),
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--'
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { type: 'field',
+        name: 'file_name_0',
+        val: 'super alpha file',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+      { type: 'field',
+        name: 'file_name_1',
+        val: 'super beta file',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('A'.repeat(1023)),
+        info: {
+          filename: '1k_a.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+      },
+      { type: 'file',
+        name: 'upload_file_1',
+        data: Buffer.from('B'.repeat(1023)),
+        info: {
+          filename: '1k_b.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Fields and files'
+  },
+  { source: [
+      ['------WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+       'Content-Disposition: form-data; name="cont"',
+       '',
+       'some random content',
+       '------WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+       'Content-Disposition: form-data; name="pass"',
+       '',
+       'some random pass',
+       '------WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+       'Content-Disposition: form-data; name=bit',
+       '',
+       '2',
+       '------WebKitFormBoundaryTB2MiQ36fnSJlrhY--'
+      ].join('\r\n')
+    ],
+    boundary: '----WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+    expected: [
+      { type: 'field',
+        name: 'cont',
+        val: 'some random content',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+      { type: 'field',
+        name: 'pass',
+        val: 'some random pass',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+      { type: 'field',
+        name: 'bit',
+        val: '2',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+    ],
+    what: 'Fields only'
+  },
+  { source: [
+      ''
+    ],
+    boundary: '----WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+    expected: [
+      { error: 'Unexpected end of form' },
+    ],
+    what: 'No fields and no files'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_0"',
+       '',
+       'super alpha file',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="1k_a.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--'
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    limits: {
+      fileSize: 13,
+      fieldSize: 5
+    },
+    expected: [
+      { type: 'field',
+        name: 'file_name_0',
+        val: 'super',
+        info: {
+          nameTruncated: false,
+          valueTruncated: true,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('ABCDEFGHIJKLM'),
+        info: {
+          filename: '1k_a.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: true,
+      },
+    ],
+    what: 'Fields and files (limits)'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_0"',
+       '',
+       'super alpha file',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="1k_a.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--'
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    limits: {
+      files: 0
+    },
+    expected: [
+      { type: 'field',
+        name: 'file_name_0',
+        val: 'super alpha file',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+      'filesLimit',
+    ],
+    what: 'Fields and files (limits: 0 files)'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_0"',
+       '',
+       'super alpha file',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_1"',
+       '',
+       'super beta file',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="1k_a.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'A'.repeat(1023),
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_1"; filename="1k_b.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'B'.repeat(1023),
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--'
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { type: 'field',
+        name: 'file_name_0',
+        val: 'super alpha file',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+      { type: 'field',
+        name: 'file_name_1',
+        val: 'super beta file',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+    ],
+    events: ['field'],
+    what: 'Fields and (ignored) files'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="/tmp/1k_a.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_1"; filename="C:\\files\\1k_b.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_2"; filename="relative/1k_c.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--'
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('ABCDEFGHIJKLMNOPQRSTUVWXYZ'),
+        info: {
+          filename: '1k_a.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+      },
+      { type: 'file',
+        name: 'upload_file_1',
+        data: Buffer.from('ABCDEFGHIJKLMNOPQRSTUVWXYZ'),
+        info: {
+          filename: '1k_b.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+      },
+      { type: 'file',
+        name: 'upload_file_2',
+        data: Buffer.from('ABCDEFGHIJKLMNOPQRSTUVWXYZ'),
+        info: {
+          filename: '1k_c.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Files with filenames containing paths'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="/absolute/1k_a.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_1"; filename="C:\\absolute\\1k_b.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_2"; filename="relative/1k_c.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--'
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    preservePath: true,
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('ABCDEFGHIJKLMNOPQRSTUVWXYZ'),
+        info: {
+          filename: '/absolute/1k_a.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+      },
+      { type: 'file',
+        name: 'upload_file_1',
+        data: Buffer.from('ABCDEFGHIJKLMNOPQRSTUVWXYZ'),
+        info: {
+          filename: 'C:\\absolute\\1k_b.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+      },
+      { type: 'file',
+        name: 'upload_file_2',
+        data: Buffer.from('ABCDEFGHIJKLMNOPQRSTUVWXYZ'),
+        info: {
+          filename: 'relative/1k_c.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Paths to be preserved through the preservePath option'
+  },
+  { source: [
+      ['------WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+       'Content-Disposition: form-data; name="cont"',
+       'Content-Type: ',
+       '',
+       'some random content',
+       '------WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+       'Content-Disposition: ',
+       '',
+       'some random pass',
+       '------WebKitFormBoundaryTB2MiQ36fnSJlrhY--'
+      ].join('\r\n')
+    ],
+    boundary: '----WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+    expected: [
+      { type: 'field',
+        name: 'cont',
+        val: 'some random content',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+    ],
+    what: 'Empty content-type and empty content-disposition'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="file"; filename*=utf-8\'\'n%C3%A4me.txt',
+       'Content-Type: application/octet-stream',
+       '',
+       'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--'
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { type: 'file',
+        name: 'file',
+        data: Buffer.from('ABCDEFGHIJKLMNOPQRSTUVWXYZ'),
+        info: {
+          filename: 'näme.txt',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Unicode filenames'
+  },
+  { source: [
+      ['--asdasdasdasd\r\n',
+       'Content-Type: text/plain\r\n',
+       'Content-Disposition: form-data; name="foo"\r\n',
+       '\r\n',
+       'asd\r\n',
+       '--asdasdasdasd--'
+      ].join(':)')
+    ],
+    boundary: 'asdasdasdasd',
+    expected: [
+      { error: 'Malformed part header' },
+      { error: 'Unexpected end of form' },
+    ],
+    what: 'Stopped mid-header'
+  },
+  { source: [
+      ['------WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+       'Content-Disposition: form-data; name="cont"',
+       'Content-Type: application/json',
+       '',
+       '{}',
+       '------WebKitFormBoundaryTB2MiQ36fnSJlrhY--',
+      ].join('\r\n')
+    ],
+    boundary: '----WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+    expected: [
+      { type: 'field',
+        name: 'cont',
+        val: '{}',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'application/json',
+        },
+      },
+    ],
+    what: 'content-type for fields'
+  },
+  { source: [
+      '------WebKitFormBoundaryTB2MiQ36fnSJlrhY--',
+    ],
+    boundary: '----WebKitFormBoundaryTB2MiQ36fnSJlrhY',
+    expected: [],
+    what: 'empty form'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name=upload_file_0; filename="1k_a.dat"',
+       'Content-Type: application/octet-stream',
+       'Content-Transfer-Encoding: binary',
+       '',
+       '',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.alloc(0),
+        info: {
+          filename: '1k_a.dat',
+          encoding: 'binary',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+        err: 'Unexpected end of form',
+      },
+      { error: 'Unexpected end of form' },
+    ],
+    what: 'Stopped mid-file #1'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name=upload_file_0; filename="1k_a.dat"',
+       'Content-Type: application/octet-stream',
+       '',
+       'a',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('a'),
+        info: {
+          filename: '1k_a.dat',
+          encoding: '7bit',
+          mimeType: 'application/octet-stream',
+        },
+        limited: false,
+        err: 'Unexpected end of form',
+      },
+      { error: 'Unexpected end of form' },
+    ],
+    what: 'Stopped mid-file #2'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="notes.txt"',
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'a',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('a'),
+        info: {
+          filename: 'notes.txt',
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Text file with charset'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="notes.txt"',
+       'Content-Type: ',
+       ' text/plain; charset=utf8',
+       '',
+       'a',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('a'),
+        info: {
+          filename: 'notes.txt',
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Folded header value'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'a',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [],
+    what: 'No Content-Disposition'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_0"',
+       '',
+       'a'.repeat(64 * 1024),
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="notes.txt"',
+       'Content-Type: ',
+       ' text/plain; charset=utf8',
+       '',
+       'bc',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    limits: {
+      fieldSize: Infinity,
+    },
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('bc'),
+        info: {
+          filename: 'notes.txt',
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+        limited: false,
+      },
+    ],
+    events: [ 'file' ],
+    what: 'Skip field parts if no listener'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_0"',
+       '',
+       'a',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="notes.txt"',
+       'Content-Type: ',
+       ' text/plain; charset=utf8',
+       '',
+       'bc',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    limits: {
+      parts: 1,
+    },
+    expected: [
+      { type: 'field',
+        name: 'file_name_0',
+        val: 'a',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+      'partsLimit',
+    ],
+    what: 'Parts limit'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_0"',
+       '',
+       'a',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; name="file_name_1"',
+       '',
+       'b',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    limits: {
+      fields: 1,
+    },
+    expected: [
+      { type: 'field',
+        name: 'file_name_0',
+        val: 'a',
+        info: {
+          nameTruncated: false,
+          valueTruncated: false,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+      },
+      'fieldsLimit',
+    ],
+    what: 'Fields limit'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="notes.txt"',
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'ab',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_1"; filename="notes2.txt"',
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'cd',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    limits: {
+      files: 1,
+    },
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('ab'),
+        info: {
+          filename: 'notes.txt',
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+        limited: false,
+      },
+      'filesLimit',
+    ],
+    what: 'Files limit'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + `name="upload_file_0"; filename="${'a'.repeat(64 * 1024)}.txt"`,
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'ab',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_1"; filename="notes2.txt"',
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'cd',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { error: 'Malformed part header' },
+      { type: 'file',
+        name: 'upload_file_1',
+        data: Buffer.from('cd'),
+        info: {
+          filename: 'notes2.txt',
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Oversized part header'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + 'name="upload_file_0"; filename="notes.txt"',
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'a'.repeat(31) + '\r',
+      ].join('\r\n'),
+      'b'.repeat(40),
+      '\r\n-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    fileHwm: 32,
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('a'.repeat(31) + '\r' + 'b'.repeat(40)),
+        info: {
+          filename: 'notes.txt',
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Lookbehind data should not stall file streams'
+  },
+  { source: [
+      ['-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + `name="upload_file_0"; filename="${'a'.repeat(8 * 1024)}.txt"`,
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'ab',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + `name="upload_file_1"; filename="${'b'.repeat(8 * 1024)}.txt"`,
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'cd',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+       'Content-Disposition: form-data; '
+         + `name="upload_file_2"; filename="${'c'.repeat(8 * 1024)}.txt"`,
+       'Content-Type: text/plain; charset=utf8',
+       '',
+       'ef',
+       '-----------------------------paZqsnEHRufoShdX6fh0lUhXBP4k--',
+      ].join('\r\n')
+    ],
+    boundary: '---------------------------paZqsnEHRufoShdX6fh0lUhXBP4k',
+    expected: [
+      { type: 'file',
+        name: 'upload_file_0',
+        data: Buffer.from('ab'),
+        info: {
+          filename: `${'a'.repeat(8 * 1024)}.txt`,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+        limited: false,
+      },
+      { type: 'file',
+        name: 'upload_file_1',
+        data: Buffer.from('cd'),
+        info: {
+          filename: `${'b'.repeat(8 * 1024)}.txt`,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+        limited: false,
+      },
+      { type: 'file',
+        name: 'upload_file_2',
+        data: Buffer.from('ef'),
+        info: {
+          filename: `${'c'.repeat(8 * 1024)}.txt`,
+          encoding: '7bit',
+          mimeType: 'text/plain',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Header size limit should be per part'
+  },
+  { source: [
+      '\r\n--d1bf46b3-aa33-4061-b28d-6c5ced8b08ee\r\n',
+      'Content-Type: application/gzip\r\n'
+        + 'Content-Encoding: gzip\r\n'
+        + 'Content-Disposition: form-data; name=batch-1; filename=batch-1'
+        + '\r\n\r\n',
+      '\r\n--d1bf46b3-aa33-4061-b28d-6c5ced8b08ee--',
+    ],
+    boundary: 'd1bf46b3-aa33-4061-b28d-6c5ced8b08ee',
+    expected: [
+      { type: 'file',
+        name: 'batch-1',
+        data: Buffer.alloc(0),
+        info: {
+          filename: 'batch-1',
+          encoding: '7bit',
+          mimeType: 'application/gzip',
+        },
+        limited: false,
+      },
+    ],
+    what: 'Empty part'
+  },
+];
+
+for (const test of tests) {
+  active.set(test, 1);
+
+  const { what, boundary, events, limits, preservePath, fileHwm } = test;
+  const bb = busboy({
+    fileHwm,
+    limits,
+    preservePath,
+    headers: {
+      'content-type': `multipart/form-data; boundary=${boundary}`,
+    }
+  });
+  const results = [];
+
+  if (events === undefined || events.includes('field')) {
+    bb.on('field', (name, val, info) => {
+      results.push({ type: 'field', name, val, info });
+    });
+  }
+
+  if (events === undefined || events.includes('file')) {
+    bb.on('file', (name, stream, info) => {
+      const data = [];
+      let nb = 0;
+      const file = {
+        type: 'file',
+        name,
+        data: null,
+        info,
+        limited: false,
+      };
+      results.push(file);
+      stream.on('data', (d) => {
+        data.push(d);
+        nb += d.length;
+      }).on('limit', () => {
+        file.limited = true;
+      }).on('close', () => {
+        file.data = Buffer.concat(data, nb);
+        assert.strictEqual(stream.truncated, file.limited);
+      }).once('error', (err) => {
+        file.err = err.message;
+      });
+    });
+  }
+
+  bb.on('error', (err) => {
+    results.push({ error: err.message });
+  });
+
+  bb.on('partsLimit', () => {
+    results.push('partsLimit');
+  });
+
+  bb.on('filesLimit', () => {
+    results.push('filesLimit');
+  });
+
+  bb.on('fieldsLimit', () => {
+    results.push('fieldsLimit');
+  });
+
+  bb.on('close', () => {
+    active.delete(test);
+
+    assert.deepStrictEqual(
+      results,
+      test.expected,
+      `[${what}] Results mismatch.\n`
+        + `Parsed: ${inspect(results)}\n`
+        + `Expected: ${inspect(test.expected)}`
+    );
+  });
+
+  for (const src of test.source) {
+    const buf = (typeof src === 'string' ? Buffer.from(src, 'utf8') : src);
+    bb.write(buf);
+  }
+  bb.end();
+}
+
+// Byte-by-byte versions
+for (let test of tests) {
+  test = { ...test };
+  test.what += ' (byte-by-byte)';
+  active.set(test, 1);
+
+  const { what, boundary, events, limits, preservePath, fileHwm } = test;
+  const bb = busboy({
+    fileHwm,
+    limits,
+    preservePath,
+    headers: {
+      'content-type': `multipart/form-data; boundary=${boundary}`,
+    }
+  });
+  const results = [];
+
+  if (events === undefined || events.includes('field')) {
+    bb.on('field', (name, val, info) => {
+      results.push({ type: 'field', name, val, info });
+    });
+  }
+
+  if (events === undefined || events.includes('file')) {
+    bb.on('file', (name, stream, info) => {
+      const data = [];
+      let nb = 0;
+      const file = {
+        type: 'file',
+        name,
+        data: null,
+        info,
+        limited: false,
+      };
+      results.push(file);
+      stream.on('data', (d) => {
+        data.push(d);
+        nb += d.length;
+      }).on('limit', () => {
+        file.limited = true;
+      }).on('close', () => {
+        file.data = Buffer.concat(data, nb);
+        assert.strictEqual(stream.truncated, file.limited);
+      }).once('error', (err) => {
+        file.err = err.message;
+      });
+    });
+  }
+
+  bb.on('error', (err) => {
+    results.push({ error: err.message });
+  });
+
+  bb.on('partsLimit', () => {
+    results.push('partsLimit');
+  });
+
+  bb.on('filesLimit', () => {
+    results.push('filesLimit');
+  });
+
+  bb.on('fieldsLimit', () => {
+    results.push('fieldsLimit');
+  });
+
+  bb.on('close', () => {
+    active.delete(test);
+
+    assert.deepStrictEqual(
+      results,
+      test.expected,
+      `[${what}] Results mismatch.\n`
+        + `Parsed: ${inspect(results)}\n`
+        + `Expected: ${inspect(test.expected)}`
+    );
+  });
+
+  for (const src of test.source) {
+    const buf = (typeof src === 'string' ? Buffer.from(src, 'utf8') : src);
+    for (let i = 0; i < buf.length; ++i)
+      bb.write(buf.slice(i, i + 1));
+  }
+  bb.end();
+}
+
+{
+  let exception = false;
+  process.once('uncaughtException', (ex) => {
+    exception = true;
+    throw ex;
+  });
+  process.on('exit', () => {
+    if (exception || active.size === 0)
+      return;
+    process.exitCode = 1;
+    console.error('==========================');
+    console.error(`${active.size} test(s) did not finish:`);
+    console.error('==========================');
+    console.error(Array.from(active.keys()).map((v) => v.what).join('\n'));
+  });
+}
diff --git a/server/node_modules/busboy/test/test-types-urlencoded.js b/server/node_modules/busboy/test/test-types-urlencoded.js
new file mode 100644
index 0000000..c35962b
--- /dev/null
+++ b/server/node_modules/busboy/test/test-types-urlencoded.js
@@ -0,0 +1,488 @@
+'use strict';
+
+const assert = require('assert');
+const { transcode } = require('buffer');
+const { inspect } = require('util');
+
+const busboy = require('..');
+
+const active = new Map();
+
+const tests = [
+  { source: ['foo'],
+    expected: [
+      ['foo',
+       '',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Unassigned value'
+  },
+  { source: ['foo=bar'],
+    expected: [
+      ['foo',
+       'bar',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Assigned value'
+  },
+  { source: ['foo&bar=baz'],
+    expected: [
+      ['foo',
+       '',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['bar',
+       'baz',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Unassigned and assigned value'
+  },
+  { source: ['foo=bar&baz'],
+    expected: [
+      ['foo',
+       'bar',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['baz',
+       '',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Assigned and unassigned value'
+  },
+  { source: ['foo=bar&baz=bla'],
+    expected: [
+      ['foo',
+       'bar',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['baz',
+       'bla',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Two assigned values'
+  },
+  { source: ['foo&bar'],
+    expected: [
+      ['foo',
+       '',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['bar',
+       '',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Two unassigned values'
+  },
+  { source: ['foo&bar&'],
+    expected: [
+      ['foo',
+       '',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['bar',
+       '',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Two unassigned values and ampersand'
+  },
+  { source: ['foo+1=bar+baz%2Bquux'],
+    expected: [
+      ['foo 1',
+       'bar baz+quux',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Assigned key and value with (plus) space'
+  },
+  { source: ['foo=bar%20baz%21'],
+    expected: [
+      ['foo',
+       'bar baz!',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Assigned value with encoded bytes'
+  },
+  { source: ['foo%20bar=baz%20bla%21'],
+    expected: [
+      ['foo bar',
+       'baz bla!',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Assigned value with encoded bytes #2'
+  },
+  { source: ['foo=bar%20baz%21&num=1000'],
+    expected: [
+      ['foo',
+       'bar baz!',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['num',
+       '1000',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Two assigned values, one with encoded bytes'
+  },
+  { source: [
+      Array.from(transcode(Buffer.from('foo'), 'utf8', 'utf16le')).map(
+        (n) => `%${n.toString(16).padStart(2, '0')}`
+      ).join(''),
+      '=',
+      Array.from(transcode(Buffer.from('😀!'), 'utf8', 'utf16le')).map(
+        (n) => `%${n.toString(16).padStart(2, '0')}`
+      ).join(''),
+    ],
+    expected: [
+      ['foo',
+       '😀!',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'UTF-16LE',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    charset: 'UTF-16LE',
+    what: 'Encoded value with multi-byte charset'
+  },
+  { source: [
+      'foo=<',
+      Array.from(transcode(Buffer.from('©:^þ'), 'utf8', 'latin1')).map(
+        (n) => `%${n.toString(16).padStart(2, '0')}`
+      ).join(''),
+    ],
+    expected: [
+      ['foo',
+       '<©:^þ',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'ISO-8859-1',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    charset: 'ISO-8859-1',
+    what: 'Encoded value with single-byte, ASCII-compatible, non-UTF8 charset'
+  },
+  { source: ['foo=bar&baz=bla'],
+    expected: [],
+    what: 'Limits: zero fields',
+    limits: { fields: 0 }
+  },
+  { source: ['foo=bar&baz=bla'],
+    expected: [
+      ['foo',
+       'bar',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Limits: one field',
+    limits: { fields: 1 }
+  },
+  { source: ['foo=bar&baz=bla'],
+    expected: [
+      ['foo',
+       'bar',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['baz',
+       'bla',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Limits: field part lengths match limits',
+    limits: { fieldNameSize: 3, fieldSize: 3 }
+  },
+  { source: ['foo=bar&baz=bla'],
+    expected: [
+      ['fo',
+       'bar',
+       { nameTruncated: true,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['ba',
+       'bla',
+       { nameTruncated: true,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Limits: truncated field name',
+    limits: { fieldNameSize: 2 }
+  },
+  { source: ['foo=bar&baz=bla'],
+    expected: [
+      ['foo',
+       'ba',
+       { nameTruncated: false,
+         valueTruncated: true,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['baz',
+       'bl',
+       { nameTruncated: false,
+         valueTruncated: true,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Limits: truncated field value',
+    limits: { fieldSize: 2 }
+  },
+  { source: ['foo=bar&baz=bla'],
+    expected: [
+      ['fo',
+       'ba',
+       { nameTruncated: true,
+         valueTruncated: true,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['ba',
+       'bl',
+       { nameTruncated: true,
+         valueTruncated: true,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Limits: truncated field name and value',
+    limits: { fieldNameSize: 2, fieldSize: 2 }
+  },
+  { source: ['foo=bar&baz=bla'],
+    expected: [
+      ['fo',
+       '',
+       { nameTruncated: true,
+         valueTruncated: true,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['ba',
+       '',
+       { nameTruncated: true,
+         valueTruncated: true,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Limits: truncated field name and zero value limit',
+    limits: { fieldNameSize: 2, fieldSize: 0 }
+  },
+  { source: ['foo=bar&baz=bla'],
+    expected: [
+      ['',
+       '',
+       { nameTruncated: true,
+         valueTruncated: true,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+      ['',
+       '',
+       { nameTruncated: true,
+         valueTruncated: true,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Limits: truncated zero field name and zero value limit',
+    limits: { fieldNameSize: 0, fieldSize: 0 }
+  },
+  { source: ['&'],
+    expected: [],
+    what: 'Ampersand'
+  },
+  { source: ['&&&&&'],
+    expected: [],
+    what: 'Many ampersands'
+  },
+  { source: ['='],
+    expected: [
+      ['',
+       '',
+       { nameTruncated: false,
+         valueTruncated: false,
+         encoding: 'utf-8',
+         mimeType: 'text/plain' },
+      ],
+    ],
+    what: 'Assigned value, empty name and value'
+  },
+  { source: [''],
+    expected: [],
+    what: 'Nothing'
+  },
+];
+
+for (const test of tests) {
+  active.set(test, 1);
+
+  const { what } = test;
+  const charset = test.charset || 'utf-8';
+  const bb = busboy({
+    limits: test.limits,
+    headers: {
+      'content-type': `application/x-www-form-urlencoded; charset=${charset}`,
+    },
+  });
+  const results = [];
+
+  bb.on('field', (key, val, info) => {
+    results.push([key, val, info]);
+  });
+
+  bb.on('file', () => {
+    throw new Error(`[${what}] Unexpected file`);
+  });
+
+  bb.on('close', () => {
+    active.delete(test);
+
+    assert.deepStrictEqual(
+      results,
+      test.expected,
+      `[${what}] Results mismatch.\n`
+        + `Parsed: ${inspect(results)}\n`
+        + `Expected: ${inspect(test.expected)}`
+    );
+  });
+
+  for (const src of test.source) {
+    const buf = (typeof src === 'string' ? Buffer.from(src, 'utf8') : src);
+    bb.write(buf);
+  }
+  bb.end();
+}
+
+// Byte-by-byte versions
+for (let test of tests) {
+  test = { ...test };
+  test.what += ' (byte-by-byte)';
+  active.set(test, 1);
+
+  const { what } = test;
+  const charset = test.charset || 'utf-8';
+  const bb = busboy({
+    limits: test.limits,
+    headers: {
+      'content-type': `application/x-www-form-urlencoded; charset="${charset}"`,
+    },
+  });
+  const results = [];
+
+  bb.on('field', (key, val, info) => {
+    results.push([key, val, info]);
+  });
+
+  bb.on('file', () => {
+    throw new Error(`[${what}] Unexpected file`);
+  });
+
+  bb.on('close', () => {
+    active.delete(test);
+
+    assert.deepStrictEqual(
+      results,
+      test.expected,
+      `[${what}] Results mismatch.\n`
+        + `Parsed: ${inspect(results)}\n`
+        + `Expected: ${inspect(test.expected)}`
+    );
+  });
+
+  for (const src of test.source) {
+    const buf = (typeof src === 'string' ? Buffer.from(src, 'utf8') : src);
+    for (let i = 0; i < buf.length; ++i)
+      bb.write(buf.slice(i, i + 1));
+  }
+  bb.end();
+}
+
+{
+  let exception = false;
+  process.once('uncaughtException', (ex) => {
+    exception = true;
+    throw ex;
+  });
+  process.on('exit', () => {
+    if (exception || active.size === 0)
+      return;
+    process.exitCode = 1;
+    console.error('==========================');
+    console.error(`${active.size} test(s) did not finish:`);
+    console.error('==========================');
+    console.error(Array.from(active.keys()).map((v) => v.what).join('\n'));
+  });
+}
diff --git a/server/node_modules/busboy/test/test.js b/server/node_modules/busboy/test/test.js
new file mode 100644
index 0000000..d0380f2
--- /dev/null
+++ b/server/node_modules/busboy/test/test.js
@@ -0,0 +1,20 @@
+'use strict';
+
+const { spawnSync } = require('child_process');
+const { readdirSync } = require('fs');
+const { join } = require('path');
+
+const files = readdirSync(__dirname).sort();
+for (const filename of files) {
+  if (filename.startsWith('test-')) {
+    const path = join(__dirname, filename);
+    console.log(`> Running ${filename} ...`);
+    const result = spawnSync(`${process.argv0} ${path}`, {
+      shell: true,
+      stdio: 'inherit',
+      windowsHide: true
+    });
+    if (result.status !== 0)
+      process.exitCode = 1;
+  }
+}
diff --git a/server/node_modules/bytes/History.md b/server/node_modules/bytes/History.md
new file mode 100644
index 0000000..d60ce0e
--- /dev/null
+++ b/server/node_modules/bytes/History.md
@@ -0,0 +1,97 @@
+3.1.2 / 2022-01-27
+==================
+
+  * Fix return value for un-parsable strings
+
+3.1.1 / 2021-11-15
+==================
+
+  * Fix "thousandsSeparator" incorrecting formatting fractional part
+
+3.1.0 / 2019-01-22
+==================
+
+  * Add petabyte (`pb`) support
+
+3.0.0 / 2017-08-31
+==================
+
+  * Change "kB" to "KB" in format output
+  * Remove support for Node.js 0.6
+  * Remove support for ComponentJS
+
+2.5.0 / 2017-03-24
+==================
+
+  * Add option "unit"
+
+2.4.0 / 2016-06-01
+==================
+
+  * Add option "unitSeparator"
+
+2.3.0 / 2016-02-15
+==================
+
+  * Drop partial bytes on all parsed units
+  * Fix non-finite numbers to `.format` to return `null`
+  * Fix parsing byte string that looks like hex
+  * perf: hoist regular expressions
+
+2.2.0 / 2015-11-13
+==================
+
+  * add option "decimalPlaces"
+  * add option "fixedDecimals"
+
+2.1.0 / 2015-05-21
+==================
+
+  * add `.format` export
+  * add `.parse` export
+
+2.0.2 / 2015-05-20
+==================
+
+  * remove map recreation
+  * remove unnecessary object construction
+
+2.0.1 / 2015-05-07
+==================
+
+  * fix browserify require
+  * remove node.extend dependency
+
+2.0.0 / 2015-04-12
+==================
+
+  * add option "case"
+  * add option "thousandsSeparator"
+  * return "null" on invalid parse input
+  * support proper round-trip: bytes(bytes(num)) === num
+  * units no longer case sensitive when parsing
+
+1.0.0 / 2014-05-05
+==================
+
+ * add negative support. fixes #6
+
+0.3.0 / 2014-03-19
+==================
+
+ * added terabyte support
+
+0.2.1 / 2013-04-01
+==================
+
+  * add .component
+
+0.2.0 / 2012-10-28
+==================
+
+  * bytes(200).should.eql('200b')
+
+0.1.0 / 2012-07-04
+==================
+
+  * add bytes to string conversion [yields]
diff --git a/server/node_modules/bytes/LICENSE b/server/node_modules/bytes/LICENSE
new file mode 100644
index 0000000..63e95a9
--- /dev/null
+++ b/server/node_modules/bytes/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2012-2014 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2015 Jed Watson <jed.watson@me.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/bytes/Readme.md b/server/node_modules/bytes/Readme.md
new file mode 100644
index 0000000..5790e23
--- /dev/null
+++ b/server/node_modules/bytes/Readme.md
@@ -0,0 +1,152 @@
+# Bytes utility
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Build Status][ci-image]][ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Utility to parse a string bytes (ex: `1TB`) to bytes (`1099511627776`) and vice-versa.
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```bash
+$ npm install bytes
+```
+
+## Usage
+
+```js
+var bytes = require('bytes');
+```
+
+#### bytes(number｜string value, [options]): number｜string｜null
+
+Default export function. Delegates to either `bytes.format` or `bytes.parse` based on the type of `value`.
+
+**Arguments**
+
+| Name    | Type     | Description        |
+|---------|----------|--------------------|
+| value   | `number`｜`string` | Number value to format or string value to parse |
+| options | `Object` | Conversion options for `format` |
+
+**Returns**
+
+| Name    | Type             | Description                                     |
+|---------|------------------|-------------------------------------------------|
+| results | `string`｜`number`｜`null` | Return null upon error. Numeric value in bytes, or string value otherwise. |
+
+**Example**
+
+```js
+bytes(1024);
+// output: '1KB'
+
+bytes('1KB');
+// output: 1024
+```
+
+#### bytes.format(number value, [options]): string｜null
+
+Format the given value in bytes into a string. If the value is negative, it is kept as such. If it is a float, it is
+ rounded.
+
+**Arguments**
+
+| Name    | Type     | Description        |
+|---------|----------|--------------------|
+| value   | `number` | Value in bytes     |
+| options | `Object` | Conversion options |
+
+**Options**
+
+| Property          | Type   | Description                                                                             |
+|-------------------|--------|-----------------------------------------------------------------------------------------|
+| decimalPlaces | `number`｜`null` | Maximum number of decimal places to include in output. Default value to `2`. |
+| fixedDecimals | `boolean`｜`null` | Whether to always display the maximum number of decimal places. Default value to `false` |
+| thousandsSeparator | `string`｜`null` | Example of values: `' '`, `','` and `'.'`... Default value to `''`. |
+| unit | `string`｜`null` | The unit in which the result will be returned (B/KB/MB/GB/TB). Default value to `''` (which means auto detect). |
+| unitSeparator | `string`｜`null` | Separator to use between number and unit. Default value to `''`. |
+
+**Returns**
+
+| Name    | Type             | Description                                     |
+|---------|------------------|-------------------------------------------------|
+| results | `string`｜`null` | Return null upon error. String value otherwise. |
+
+**Example**
+
+```js
+bytes.format(1024);
+// output: '1KB'
+
+bytes.format(1000);
+// output: '1000B'
+
+bytes.format(1000, {thousandsSeparator: ' '});
+// output: '1 000B'
+
+bytes.format(1024 * 1.7, {decimalPlaces: 0});
+// output: '2KB'
+
+bytes.format(1024, {unitSeparator: ' '});
+// output: '1 KB'
+```
+
+#### bytes.parse(string｜number value): number｜null
+
+Parse the string value into an integer in bytes. If no unit is given, or `value`
+is a number, it is assumed the value is in bytes.
+
+Supported units and abbreviations are as follows and are case-insensitive:
+
+  * `b` for bytes
+  * `kb` for kilobytes
+  * `mb` for megabytes
+  * `gb` for gigabytes
+  * `tb` for terabytes
+  * `pb` for petabytes
+
+The units are in powers of two, not ten. This means 1kb = 1024b according to this parser.
+
+**Arguments**
+
+| Name          | Type   | Description        |
+|---------------|--------|--------------------|
+| value   | `string`｜`number` | String to parse, or number in bytes.   |
+
+**Returns**
+
+| Name    | Type        | Description             |
+|---------|-------------|-------------------------|
+| results | `number`｜`null` | Return null upon error. Value in bytes otherwise. |
+
+**Example**
+
+```js
+bytes.parse('1KB');
+// output: 1024
+
+bytes.parse('1024');
+// output: 1024
+
+bytes.parse(1024);
+// output: 1024
+```
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/visionmedia/bytes.js/master?label=ci
+[ci-url]: https://github.com/visionmedia/bytes.js/actions?query=workflow%3Aci
+[coveralls-image]: https://badgen.net/coveralls/c/github/visionmedia/bytes.js/master
+[coveralls-url]: https://coveralls.io/r/visionmedia/bytes.js?branch=master
+[downloads-image]: https://badgen.net/npm/dm/bytes
+[downloads-url]: https://npmjs.org/package/bytes
+[npm-image]: https://badgen.net/npm/v/bytes
+[npm-url]: https://npmjs.org/package/bytes
diff --git a/server/node_modules/bytes/index.js b/server/node_modules/bytes/index.js
new file mode 100644
index 0000000..6f2d0f8
--- /dev/null
+++ b/server/node_modules/bytes/index.js
@@ -0,0 +1,170 @@
+/*!
+ * bytes
+ * Copyright(c) 2012-2014 TJ Holowaychuk
+ * Copyright(c) 2015 Jed Watson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = bytes;
+module.exports.format = format;
+module.exports.parse = parse;
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var formatThousandsRegExp = /\B(?=(\d{3})+(?!\d))/g;
+
+var formatDecimalsRegExp = /(?:\.0*|(\.[^0]+)0+)$/;
+
+var map = {
+  b:  1,
+  kb: 1 << 10,
+  mb: 1 << 20,
+  gb: 1 << 30,
+  tb: Math.pow(1024, 4),
+  pb: Math.pow(1024, 5),
+};
+
+var parseRegExp = /^((-|\+)?(\d+(?:\.\d+)?)) *(kb|mb|gb|tb|pb)$/i;
+
+/**
+ * Convert the given value in bytes into a string or parse to string to an integer in bytes.
+ *
+ * @param {string|number} value
+ * @param {{
+ *  case: [string],
+ *  decimalPlaces: [number]
+ *  fixedDecimals: [boolean]
+ *  thousandsSeparator: [string]
+ *  unitSeparator: [string]
+ *  }} [options] bytes options.
+ *
+ * @returns {string|number|null}
+ */
+
+function bytes(value, options) {
+  if (typeof value === 'string') {
+    return parse(value);
+  }
+
+  if (typeof value === 'number') {
+    return format(value, options);
+  }
+
+  return null;
+}
+
+/**
+ * Format the given value in bytes into a string.
+ *
+ * If the value is negative, it is kept as such. If it is a float,
+ * it is rounded.
+ *
+ * @param {number} value
+ * @param {object} [options]
+ * @param {number} [options.decimalPlaces=2]
+ * @param {number} [options.fixedDecimals=false]
+ * @param {string} [options.thousandsSeparator=]
+ * @param {string} [options.unit=]
+ * @param {string} [options.unitSeparator=]
+ *
+ * @returns {string|null}
+ * @public
+ */
+
+function format(value, options) {
+  if (!Number.isFinite(value)) {
+    return null;
+  }
+
+  var mag = Math.abs(value);
+  var thousandsSeparator = (options && options.thousandsSeparator) || '';
+  var unitSeparator = (options && options.unitSeparator) || '';
+  var decimalPlaces = (options && options.decimalPlaces !== undefined) ? options.decimalPlaces : 2;
+  var fixedDecimals = Boolean(options && options.fixedDecimals);
+  var unit = (options && options.unit) || '';
+
+  if (!unit || !map[unit.toLowerCase()]) {
+    if (mag >= map.pb) {
+      unit = 'PB';
+    } else if (mag >= map.tb) {
+      unit = 'TB';
+    } else if (mag >= map.gb) {
+      unit = 'GB';
+    } else if (mag >= map.mb) {
+      unit = 'MB';
+    } else if (mag >= map.kb) {
+      unit = 'KB';
+    } else {
+      unit = 'B';
+    }
+  }
+
+  var val = value / map[unit.toLowerCase()];
+  var str = val.toFixed(decimalPlaces);
+
+  if (!fixedDecimals) {
+    str = str.replace(formatDecimalsRegExp, '$1');
+  }
+
+  if (thousandsSeparator) {
+    str = str.split('.').map(function (s, i) {
+      return i === 0
+        ? s.replace(formatThousandsRegExp, thousandsSeparator)
+        : s
+    }).join('.');
+  }
+
+  return str + unitSeparator + unit;
+}
+
+/**
+ * Parse the string value into an integer in bytes.
+ *
+ * If no unit is given, it is assumed the value is in bytes.
+ *
+ * @param {number|string} val
+ *
+ * @returns {number|null}
+ * @public
+ */
+
+function parse(val) {
+  if (typeof val === 'number' && !isNaN(val)) {
+    return val;
+  }
+
+  if (typeof val !== 'string') {
+    return null;
+  }
+
+  // Test if the string passed is valid
+  var results = parseRegExp.exec(val);
+  var floatValue;
+  var unit = 'b';
+
+  if (!results) {
+    // Nothing could be extracted from the given string
+    floatValue = parseInt(val, 10);
+    unit = 'b'
+  } else {
+    // Retrieve the value and the unit
+    floatValue = parseFloat(results[1]);
+    unit = results[4].toLowerCase();
+  }
+
+  if (isNaN(floatValue)) {
+    return null;
+  }
+
+  return Math.floor(map[unit] * floatValue);
+}
diff --git a/server/node_modules/bytes/package.json b/server/node_modules/bytes/package.json
new file mode 100644
index 0000000..f2b6a8b
--- /dev/null
+++ b/server/node_modules/bytes/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "bytes",
+  "description": "Utility to parse a string bytes to bytes and vice-versa",
+  "version": "3.1.2",
+  "author": "TJ Holowaychuk <tj@vision-media.ca> (http://tjholowaychuk.com)",
+  "contributors": [
+    "Jed Watson <jed.watson@me.com>",
+    "Théo FIDRY <theo.fidry@gmail.com>"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "byte",
+    "bytes",
+    "utility",
+    "parse",
+    "parser",
+    "convert",
+    "converter"
+  ],
+  "repository": "visionmedia/bytes.js",
+  "devDependencies": {
+    "eslint": "7.32.0",
+    "eslint-plugin-markdown": "2.2.1",
+    "mocha": "9.2.0",
+    "nyc": "15.1.0"
+  },
+  "files": [
+    "History.md",
+    "LICENSE",
+    "Readme.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --check-leaks --reporter spec",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/cacache/LICENSE.md b/server/node_modules/cacache/LICENSE.md
new file mode 100644
index 0000000..8d28acf
--- /dev/null
+++ b/server/node_modules/cacache/LICENSE.md
@@ -0,0 +1,16 @@
+ISC License
+
+Copyright (c) npm, Inc.
+
+Permission to use, copy, modify, and/or distribute this software for
+any purpose with or without fee is hereby granted, provided that the
+above copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE COPYRIGHT HOLDER DISCLAIMS
+ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/cacache/README.md b/server/node_modules/cacache/README.md
new file mode 100644
index 0000000..6dc11ba
--- /dev/null
+++ b/server/node_modules/cacache/README.md
@@ -0,0 +1,703 @@
+# cacache [![npm version](https://img.shields.io/npm/v/cacache.svg)](https://npm.im/cacache) [![license](https://img.shields.io/npm/l/cacache.svg)](https://npm.im/cacache) [![Travis](https://img.shields.io/travis/npm/cacache.svg)](https://travis-ci.org/npm/cacache) [![AppVeyor](https://ci.appveyor.com/api/projects/status/github/npm/cacache?svg=true)](https://ci.appveyor.com/project/npm/cacache) [![Coverage Status](https://coveralls.io/repos/github/npm/cacache/badge.svg?branch=latest)](https://coveralls.io/github/npm/cacache?branch=latest)
+
+[`cacache`](https://github.com/npm/cacache) is a Node.js library for managing
+local key and content address caches. It's really fast, really good at
+concurrency, and it will never give you corrupted data, even if cache files
+get corrupted or manipulated.
+
+On systems that support user and group settings on files, cacache will
+match the `uid` and `gid` values to the folder where the cache lives, even
+when running as `root`.
+
+It was written to be used as [npm](https://npm.im)'s local cache, but can
+just as easily be used on its own.
+
+## Install
+
+`$ npm install --save cacache`
+
+## Table of Contents
+
+* [Example](#example)
+* [Features](#features)
+* [Contributing](#contributing)
+* [API](#api)
+  * [Using localized APIs](#localized-api)
+  * Reading
+    * [`ls`](#ls)
+    * [`ls.stream`](#ls-stream)
+    * [`get`](#get-data)
+    * [`get.stream`](#get-stream)
+    * [`get.info`](#get-info)
+    * [`get.hasContent`](#get-hasContent)
+  * Writing
+    * [`put`](#put-data)
+    * [`put.stream`](#put-stream)
+    * [`rm.all`](#rm-all)
+    * [`rm.entry`](#rm-entry)
+    * [`rm.content`](#rm-content)
+    * [`index.compact`](#index-compact)
+    * [`index.insert`](#index-insert)
+  * Utilities
+    * [`clearMemoized`](#clear-memoized)
+    * [`tmp.mkdir`](#tmp-mkdir)
+    * [`tmp.withTmp`](#with-tmp)
+  * Integrity
+    * [Subresource Integrity](#integrity)
+    * [`verify`](#verify)
+    * [`verify.lastRun`](#verify-last-run)
+
+### Example
+
+```javascript
+const cacache = require('cacache')
+const fs = require('fs')
+
+const tarball = '/path/to/mytar.tgz'
+const cachePath = '/tmp/my-toy-cache'
+const key = 'my-unique-key-1234'
+
+// Cache it! Use `cachePath` as the root of the content cache
+cacache.put(cachePath, key, '10293801983029384').then(integrity => {
+  console.log(`Saved content to ${cachePath}.`)
+})
+
+const destination = '/tmp/mytar.tgz'
+
+// Copy the contents out of the cache and into their destination!
+// But this time, use stream instead!
+cacache.get.stream(
+  cachePath, key
+).pipe(
+  fs.createWriteStream(destination)
+).on('finish', () => {
+  console.log('done extracting!')
+})
+
+// The same thing, but skip the key index.
+cacache.get.byDigest(cachePath, integrityHash).then(data => {
+  fs.writeFile(destination, data, err => {
+    console.log('tarball data fetched based on its sha512sum and written out!')
+  })
+})
+```
+
+### Features
+
+* Extraction by key or by content address (shasum, etc)
+* [Subresource Integrity](#integrity) web standard support
+* Multi-hash support - safely host sha1, sha512, etc, in a single cache
+* Automatic content deduplication
+* Fault tolerance (immune to corruption, partial writes, process races, etc)
+* Consistency guarantees on read and write (full data verification)
+* Lockless, high-concurrency cache access
+* Streaming support
+* Promise support
+* Fast -- sub-millisecond reads and writes including verification
+* Arbitrary metadata storage
+* Garbage collection and additional offline verification
+* Thorough test coverage
+* There's probably a bloom filter in there somewhere. Those are cool, right? 🤔
+
+### Contributing
+
+The cacache team enthusiastically welcomes contributions and project participation! There's a bunch of things you can do if you want to contribute! The [Contributor Guide](CONTRIBUTING.md) has all the information you need for everything from reporting bugs to contributing entire new features. Please don't hesitate to jump in if you'd like to, or even ask us questions if something isn't clear.
+
+All participants and maintainers in this project are expected to follow [Code of Conduct](CODE_OF_CONDUCT.md), and just generally be excellent to each other.
+
+Please refer to the [Changelog](CHANGELOG.md) for project history details, too.
+
+Happy hacking!
+
+### API
+
+#### <a name="ls"></a> `> cacache.ls(cache) -> Promise<Object>`
+
+Lists info for all entries currently in the cache as a single large object. Each
+entry in the object will be keyed by the unique index key, with corresponding
+[`get.info`](#get-info) objects as the values.
+
+##### Example
+
+```javascript
+cacache.ls(cachePath).then(console.log)
+// Output
+{
+  'my-thing': {
+    key: 'my-thing',
+    integrity: 'sha512-BaSe64/EnCoDED+HAsh=='
+    path: '.testcache/content/deadbeef', // joined with `cachePath`
+    time: 12345698490,
+    size: 4023948,
+    metadata: {
+      name: 'blah',
+      version: '1.2.3',
+      description: 'this was once a package but now it is my-thing'
+    }
+  },
+  'other-thing': {
+    key: 'other-thing',
+    integrity: 'sha1-ANothER+hasH=',
+    path: '.testcache/content/bada55',
+    time: 11992309289,
+    size: 111112
+  }
+}
+```
+
+#### <a name="ls-stream"></a> `> cacache.ls.stream(cache) -> Readable`
+
+Lists info for all entries currently in the cache as a single large object.
+
+This works just like [`ls`](#ls), except [`get.info`](#get-info) entries are
+returned as `'data'` events on the returned stream.
+
+##### Example
+
+```javascript
+cacache.ls.stream(cachePath).on('data', console.log)
+// Output
+{
+  key: 'my-thing',
+  integrity: 'sha512-BaSe64HaSh',
+  path: '.testcache/content/deadbeef', // joined with `cachePath`
+  time: 12345698490,
+  size: 13423,
+  metadata: {
+    name: 'blah',
+    version: '1.2.3',
+    description: 'this was once a package but now it is my-thing'
+  }
+}
+
+{
+  key: 'other-thing',
+  integrity: 'whirlpool-WoWSoMuchSupport',
+  path: '.testcache/content/bada55',
+  time: 11992309289,
+  size: 498023984029
+}
+
+{
+  ...
+}
+```
+
+#### <a name="get-data"></a> `> cacache.get(cache, key, [opts]) -> Promise({data, metadata, integrity})`
+
+Returns an object with the cached data, digest, and metadata identified by
+`key`. The `data` property of this object will be a `Buffer` instance that
+presumably holds some data that means something to you. I'm sure you know what
+to do with it! cacache just won't care.
+
+`integrity` is a [Subresource
+Integrity](#integrity)
+string. That is, a string that can be used to verify `data`, which looks like
+`<hash-algorithm>-<base64-integrity-hash>`.
+
+If there is no content identified by `key`, or if the locally-stored data does
+not pass the validity checksum, the promise will be rejected.
+
+A sub-function, `get.byDigest` may be used for identical behavior, except lookup
+will happen by integrity hash, bypassing the index entirely. This version of the
+function *only* returns `data` itself, without any wrapper.
+
+See: [options](#get-options)
+
+##### Note
+
+This function loads the entire cache entry into memory before returning it. If
+you're dealing with Very Large data, consider using [`get.stream`](#get-stream)
+instead.
+
+##### Example
+
+```javascript
+// Look up by key
+cache.get(cachePath, 'my-thing').then(console.log)
+// Output:
+{
+  metadata: {
+    thingName: 'my'
+  },
+  integrity: 'sha512-BaSe64HaSh',
+  data: Buffer#<deadbeef>,
+  size: 9320
+}
+
+// Look up by digest
+cache.get.byDigest(cachePath, 'sha512-BaSe64HaSh').then(console.log)
+// Output:
+Buffer#<deadbeef>
+```
+
+#### <a name="get-stream"></a> `> cacache.get.stream(cache, key, [opts]) -> Readable`
+
+Returns a [Readable Stream](https://nodejs.org/api/stream.html#stream_readable_streams) of the cached data identified by `key`.
+
+If there is no content identified by `key`, or if the locally-stored data does
+not pass the validity checksum, an error will be emitted.
+
+`metadata` and `integrity` events will be emitted before the stream closes, if
+you need to collect that extra data about the cached entry.
+
+A sub-function, `get.stream.byDigest` may be used for identical behavior,
+except lookup will happen by integrity hash, bypassing the index entirely. This
+version does not emit the `metadata` and `integrity` events at all.
+
+See: [options](#get-options)
+
+##### Example
+
+```javascript
+// Look up by key
+cache.get.stream(
+  cachePath, 'my-thing'
+).on('metadata', metadata => {
+  console.log('metadata:', metadata)
+}).on('integrity', integrity => {
+  console.log('integrity:', integrity)
+}).pipe(
+  fs.createWriteStream('./x.tgz')
+)
+// Outputs:
+metadata: { ... }
+integrity: 'sha512-SoMeDIGest+64=='
+
+// Look up by digest
+cache.get.stream.byDigest(
+  cachePath, 'sha512-SoMeDIGest+64=='
+).pipe(
+  fs.createWriteStream('./x.tgz')
+)
+```
+
+#### <a name="get-info"></a> `> cacache.get.info(cache, key) -> Promise`
+
+Looks up `key` in the cache index, returning information about the entry if
+one exists.
+
+##### Fields
+
+* `key` - Key the entry was looked up under. Matches the `key` argument.
+* `integrity` - [Subresource Integrity hash](#integrity) for the content this entry refers to.
+* `path` - Filesystem path where content is stored, joined with `cache` argument.
+* `time` - Timestamp the entry was first added on.
+* `metadata` - User-assigned metadata associated with the entry/content.
+
+##### Example
+
+```javascript
+cacache.get.info(cachePath, 'my-thing').then(console.log)
+
+// Output
+{
+  key: 'my-thing',
+  integrity: 'sha256-MUSTVERIFY+ALL/THINGS=='
+  path: '.testcache/content/deadbeef',
+  time: 12345698490,
+  size: 849234,
+  metadata: {
+    name: 'blah',
+    version: '1.2.3',
+    description: 'this was once a package but now it is my-thing'
+  }
+}
+```
+
+#### <a name="get-hasContent"></a> `> cacache.get.hasContent(cache, integrity) -> Promise`
+
+Looks up a [Subresource Integrity hash](#integrity) in the cache. If content
+exists for this `integrity`, it will return an object, with the specific single integrity hash
+that was found in `sri` key, and the size of the found content as `size`. If no content exists for this integrity, it will return `false`.
+
+##### Example
+
+```javascript
+cacache.get.hasContent(cachePath, 'sha256-MUSTVERIFY+ALL/THINGS==').then(console.log)
+
+// Output
+{
+  sri: {
+    source: 'sha256-MUSTVERIFY+ALL/THINGS==',
+    algorithm: 'sha256',
+    digest: 'MUSTVERIFY+ALL/THINGS==',
+    options: []
+  },
+  size: 9001
+}
+
+cacache.get.hasContent(cachePath, 'sha521-NOT+IN/CACHE==').then(console.log)
+
+// Output
+false
+```
+
+##### <a name="get-options"></a> Options
+
+##### `opts.integrity`
+If present, the pre-calculated digest for the inserted content. If this option
+is provided and does not match the post-insertion digest, insertion will fail
+with an `EINTEGRITY` error.
+
+##### `opts.memoize`
+
+Default: null
+
+If explicitly truthy, cacache will read from memory and memoize data on bulk read. If `false`, cacache will read from disk data. Reader functions by default read from in-memory cache.
+
+##### `opts.size`
+If provided, the data stream will be verified to check that enough data was
+passed through. If there's more or less data than expected, insertion will fail
+with an `EBADSIZE` error.
+
+
+#### <a name="put-data"></a> `> cacache.put(cache, key, data, [opts]) -> Promise`
+
+Inserts data passed to it into the cache. The returned Promise resolves with a
+digest (generated according to [`opts.algorithms`](#optsalgorithms)) after the
+cache entry has been successfully written.
+
+See: [options](#put-options)
+
+##### Example
+
+```javascript
+fetch(
+  'https://registry.npmjs.org/cacache/-/cacache-1.0.0.tgz'
+).then(data => {
+  return cacache.put(cachePath, 'registry.npmjs.org|cacache@1.0.0', data)
+}).then(integrity => {
+  console.log('integrity hash is', integrity)
+})
+```
+
+#### <a name="put-stream"></a> `> cacache.put.stream(cache, key, [opts]) -> Writable`
+
+Returns a [Writable
+Stream](https://nodejs.org/api/stream.html#stream_writable_streams) that inserts
+data written to it into the cache. Emits an `integrity` event with the digest of
+written contents when it succeeds.
+
+See: [options](#put-options)
+
+##### Example
+
+```javascript
+request.get(
+  'https://registry.npmjs.org/cacache/-/cacache-1.0.0.tgz'
+).pipe(
+  cacache.put.stream(
+    cachePath, 'registry.npmjs.org|cacache@1.0.0'
+  ).on('integrity', d => console.log(`integrity digest is ${d}`))
+)
+```
+
+##### <a name="put-options"></a> Options
+
+##### `opts.metadata`
+
+Arbitrary metadata to be attached to the inserted key.
+
+##### `opts.size`
+
+If provided, the data stream will be verified to check that enough data was
+passed through. If there's more or less data than expected, insertion will fail
+with an `EBADSIZE` error.
+
+##### `opts.integrity`
+
+If present, the pre-calculated digest for the inserted content. If this option
+is provided and does not match the post-insertion digest, insertion will fail
+with an `EINTEGRITY` error.
+
+`algorithms` has no effect if this option is present.
+
+##### `opts.algorithms`
+
+Default: ['sha512']
+
+Hashing algorithms to use when calculating the [subresource integrity
+digest](#integrity)
+for inserted data. Can use any algorithm listed in `crypto.getHashes()` or
+`'omakase'`/`'お任せします'` to pick a random hash algorithm on each insertion. You
+may also use any anagram of `'modnar'` to use this feature.
+
+Currently only supports one algorithm at a time (i.e., an array length of
+exactly `1`). Has no effect if `opts.integrity` is present.
+
+##### `opts.memoize`
+
+Default: null
+
+If provided, cacache will memoize the given cache insertion in memory, bypassing
+any filesystem checks for that key or digest in future cache fetches. Nothing
+will be written to the in-memory cache unless this option is explicitly truthy.
+
+If `opts.memoize` is an object or a `Map`-like (that is, an object with `get`
+and `set` methods), it will be written to instead of the global memoization
+cache.
+
+Reading from disk data can be forced by explicitly passing `memoize: false` to
+the reader functions, but their default will be to read from memory.
+
+##### `opts.tmpPrefix`
+Default: null
+
+Prefix to append on the temporary directory name inside the cache's tmp dir. 
+
+#### <a name="rm-all"></a> `> cacache.rm.all(cache) -> Promise`
+
+Clears the entire cache. Mainly by blowing away the cache directory itself.
+
+##### Example
+
+```javascript
+cacache.rm.all(cachePath).then(() => {
+  console.log('THE APOCALYPSE IS UPON US 😱')
+})
+```
+
+#### <a name="rm-entry"></a> `> cacache.rm.entry(cache, key, [opts]) -> Promise`
+
+Alias: `cacache.rm`
+
+Removes the index entry for `key`. Content will still be accessible if
+requested directly by content address ([`get.stream.byDigest`](#get-stream)).
+
+By default, this appends a new entry to the index with an integrity of `null`.
+If `opts.removeFully` is set to `true` then the index file itself will be
+physically deleted rather than appending a `null`.
+
+To remove the content itself (which might still be used by other entries), use
+[`rm.content`](#rm-content). Or, to safely vacuum any unused content, use
+[`verify`](#verify).
+
+##### Example
+
+```javascript
+cacache.rm.entry(cachePath, 'my-thing').then(() => {
+  console.log('I did not like it anyway')
+})
+```
+
+#### <a name="rm-content"></a> `> cacache.rm.content(cache, integrity) -> Promise`
+
+Removes the content identified by `integrity`. Any index entries referring to it
+will not be usable again until the content is re-added to the cache with an
+identical digest.
+
+##### Example
+
+```javascript
+cacache.rm.content(cachePath, 'sha512-SoMeDIGest/IN+BaSE64==').then(() => {
+  console.log('data for my-thing is gone!')
+})
+```
+
+#### <a name="index-compact"></a> `> cacache.index.compact(cache, key, matchFn, [opts]) -> Promise`
+
+Uses `matchFn`, which must be a synchronous function that accepts two entries
+and returns a boolean indicating whether or not the two entries match, to
+deduplicate all entries in the cache for the given `key`.
+
+If `opts.validateEntry` is provided, it will be called as a function with the
+only parameter being a single index entry. The function must return a Boolean,
+if it returns `true` the entry is considered valid and will be kept in the index,
+if it returns `false` the entry will be removed from the index.
+
+If `opts.validateEntry` is not provided, however, every entry in the index will
+be deduplicated and kept until the first `null` integrity is reached, removing
+all entries that were written before the `null`.
+
+The deduplicated list of entries is both written to the index, replacing the
+existing content, and returned in the Promise.
+
+#### <a name="index-insert"></a> `> cacache.index.insert(cache, key, integrity, opts) -> Promise`
+
+Writes an index entry to the cache for the given `key` without writing content.
+
+It is assumed if you are using this method, you have already stored the content
+some other way and you only wish to add a new index to that content. The `metadata`
+and `size` properties are read from `opts` and used as part of the index entry.
+
+Returns a Promise resolving to the newly added entry.
+
+#### <a name="clear-memoized"></a> `> cacache.clearMemoized()`
+
+Completely resets the in-memory entry cache.
+
+#### <a name="tmp-mkdir"></a> `> tmp.mkdir(cache, opts) -> Promise<Path>`
+
+Returns a unique temporary directory inside the cache's `tmp` dir. This
+directory will use the same safe user assignment that all the other stuff use.
+
+Once the directory is made, it's the user's responsibility that all files
+within are given the appropriate `gid`/`uid` ownership settings to match
+the rest of the cache. If not, you can ask cacache to do it for you by
+calling [`tmp.fix()`](#tmp-fix), which will fix all tmp directory
+permissions.
+
+If you want automatic cleanup of this directory, use
+[`tmp.withTmp()`](#with-tpm)
+
+See: [options](#tmp-options)
+
+##### Example
+
+```javascript
+cacache.tmp.mkdir(cache).then(dir => {
+  fs.writeFile(path.join(dir, 'blablabla'), Buffer#<1234>, ...)
+})
+```
+
+#### <a name="tmp-fix"></a> `> tmp.fix(cache) -> Promise`
+
+Sets the `uid` and `gid` properties on all files and folders within the tmp
+folder to match the rest of the cache.
+
+Use this after manually writing files into [`tmp.mkdir`](#tmp-mkdir) or
+[`tmp.withTmp`](#with-tmp).
+
+##### Example
+
+```javascript
+cacache.tmp.mkdir(cache).then(dir => {
+  writeFile(path.join(dir, 'file'), someData).then(() => {
+    // make sure we didn't just put a root-owned file in the cache
+    cacache.tmp.fix().then(() => {
+      // all uids and gids match now
+    })
+  })
+})
+```
+
+#### <a name="with-tmp"></a> `> tmp.withTmp(cache, opts, cb) -> Promise`
+
+Creates a temporary directory with [`tmp.mkdir()`](#tmp-mkdir) and calls `cb`
+with it. The created temporary directory will be removed when the return value
+of `cb()` resolves, the tmp directory will be automatically deleted once that 
+promise completes.
+
+The same caveats apply when it comes to managing permissions for the tmp dir's
+contents.
+
+See: [options](#tmp-options)
+
+##### Example
+
+```javascript
+cacache.tmp.withTmp(cache, dir => {
+  return fs.writeFileAsync(path.join(dir, 'blablabla'), Buffer#<1234>, ...)
+}).then(() => {
+  // `dir` no longer exists
+})
+```
+
+##### <a name="tmp-options"></a> Options
+
+##### `opts.tmpPrefix`
+Default: null
+
+Prefix to append on the temporary directory name inside the cache's tmp dir. 
+
+#### <a name="integrity"></a> Subresource Integrity Digests
+
+For content verification and addressing, cacache uses strings following the
+[Subresource
+Integrity spec](https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity).
+That is, any time cacache expects an `integrity` argument or option, it
+should be in the format `<hashAlgorithm>-<base64-hash>`.
+
+One deviation from the current spec is that cacache will support any hash
+algorithms supported by the underlying Node.js process. You can use
+`crypto.getHashes()` to see which ones you can use.
+
+##### Generating Digests Yourself
+
+If you have an existing content shasum, they are generally formatted as a
+hexadecimal string (that is, a sha1 would look like:
+`5f5513f8822fdbe5145af33b64d8d970dcf95c6e`). In order to be compatible with
+cacache, you'll need to convert this to an equivalent subresource integrity
+string. For this example, the corresponding hash would be:
+`sha1-X1UT+IIv2+UUWvM7ZNjZcNz5XG4=`.
+
+If you want to generate an integrity string yourself for existing data, you can
+use something like this:
+
+```javascript
+const crypto = require('crypto')
+const hashAlgorithm = 'sha512'
+const data = 'foobarbaz'
+
+const integrity = (
+  hashAlgorithm +
+  '-' +
+  crypto.createHash(hashAlgorithm).update(data).digest('base64')
+)
+```
+
+You can also use [`ssri`](https://npm.im/ssri) to have a richer set of functionality
+around SRI strings, including generation, parsing, and translating from existing
+hex-formatted strings.
+
+#### <a name="verify"></a> `> cacache.verify(cache, opts) -> Promise`
+
+Checks out and fixes up your cache:
+
+* Cleans up corrupted or invalid index entries.
+* Custom entry filtering options.
+* Garbage collects any content entries not referenced by the index.
+* Checks integrity for all content entries and removes invalid content.
+* Fixes cache ownership.
+* Removes the `tmp` directory in the cache and all its contents.
+
+When it's done, it'll return an object with various stats about the verification
+process, including amount of storage reclaimed, number of valid entries, number
+of entries removed, etc.
+
+##### <a name="verify-options"></a> Options
+
+##### `opts.concurrency`
+
+Default: 20
+
+Number of concurrently read files in the filesystem while doing clean up.
+
+##### `opts.filter`
+Receives a formatted entry. Return false to remove it.
+Note: might be called more than once on the same entry.
+
+##### `opts.log`
+Custom logger function:
+```
+  log: { silly () {} }
+  log.silly('verify', 'verifying cache at', cache)
+```
+
+##### Example
+
+```sh
+echo somegarbage >> $CACHEPATH/content/deadbeef
+```
+
+```javascript
+cacache.verify(cachePath).then(stats => {
+  // deadbeef collected, because of invalid checksum.
+  console.log('cache is much nicer now! stats:', stats)
+})
+```
+
+#### <a name="verify-last-run"></a> `> cacache.verify.lastRun(cache) -> Promise`
+
+Returns a `Date` representing the last time `cacache.verify` was run on `cache`.
+
+##### Example
+
+```javascript
+cacache.verify(cachePath).then(() => {
+  cacache.verify.lastRun(cachePath).then(lastTime => {
+    console.log('cacache.verify was last called on' + lastTime)
+  })
+})
+```
diff --git a/server/node_modules/cacache/get.js b/server/node_modules/cacache/get.js
new file mode 100644
index 0000000..4e905e7
--- /dev/null
+++ b/server/node_modules/cacache/get.js
@@ -0,0 +1,237 @@
+'use strict'
+
+const Collect = require('minipass-collect')
+const Minipass = require('minipass')
+const Pipeline = require('minipass-pipeline')
+const fs = require('fs')
+const util = require('util')
+
+const index = require('./lib/entry-index')
+const memo = require('./lib/memoization')
+const read = require('./lib/content/read')
+
+const writeFile = util.promisify(fs.writeFile)
+
+function getData (cache, key, opts = {}) {
+  const { integrity, memoize, size } = opts
+  const memoized = memo.get(cache, key, opts)
+  if (memoized && memoize !== false) {
+    return Promise.resolve({
+      metadata: memoized.entry.metadata,
+      data: memoized.data,
+      integrity: memoized.entry.integrity,
+      size: memoized.entry.size,
+    })
+  }
+
+  return index.find(cache, key, opts).then((entry) => {
+    if (!entry)
+      throw new index.NotFoundError(cache, key)
+
+    return read(cache, entry.integrity, { integrity, size }).then((data) => {
+      if (memoize)
+        memo.put(cache, entry, data, opts)
+
+      return {
+        data,
+        metadata: entry.metadata,
+        size: entry.size,
+        integrity: entry.integrity,
+      }
+    })
+  })
+}
+module.exports = getData
+
+function getDataByDigest (cache, key, opts = {}) {
+  const { integrity, memoize, size } = opts
+  const memoized = memo.get.byDigest(cache, key, opts)
+  if (memoized && memoize !== false)
+    return Promise.resolve(memoized)
+
+  return read(cache, key, { integrity, size }).then((res) => {
+    if (memoize)
+      memo.put.byDigest(cache, key, res, opts)
+    return res
+  })
+}
+module.exports.byDigest = getDataByDigest
+
+function getDataSync (cache, key, opts = {}) {
+  const { integrity, memoize, size } = opts
+  const memoized = memo.get(cache, key, opts)
+
+  if (memoized && memoize !== false) {
+    return {
+      metadata: memoized.entry.metadata,
+      data: memoized.data,
+      integrity: memoized.entry.integrity,
+      size: memoized.entry.size,
+    }
+  }
+  const entry = index.find.sync(cache, key, opts)
+  if (!entry)
+    throw new index.NotFoundError(cache, key)
+  const data = read.sync(cache, entry.integrity, {
+    integrity: integrity,
+    size: size,
+  })
+  const res = {
+    metadata: entry.metadata,
+    data: data,
+    size: entry.size,
+    integrity: entry.integrity,
+  }
+  if (memoize)
+    memo.put(cache, entry, res.data, opts)
+
+  return res
+}
+
+module.exports.sync = getDataSync
+
+function getDataByDigestSync (cache, digest, opts = {}) {
+  const { integrity, memoize, size } = opts
+  const memoized = memo.get.byDigest(cache, digest, opts)
+
+  if (memoized && memoize !== false)
+    return memoized
+
+  const res = read.sync(cache, digest, {
+    integrity: integrity,
+    size: size,
+  })
+  if (memoize)
+    memo.put.byDigest(cache, digest, res, opts)
+
+  return res
+}
+module.exports.sync.byDigest = getDataByDigestSync
+
+const getMemoizedStream = (memoized) => {
+  const stream = new Minipass()
+  stream.on('newListener', function (ev, cb) {
+    ev === 'metadata' && cb(memoized.entry.metadata)
+    ev === 'integrity' && cb(memoized.entry.integrity)
+    ev === 'size' && cb(memoized.entry.size)
+  })
+  stream.end(memoized.data)
+  return stream
+}
+
+function getStream (cache, key, opts = {}) {
+  const { memoize, size } = opts
+  const memoized = memo.get(cache, key, opts)
+  if (memoized && memoize !== false)
+    return getMemoizedStream(memoized)
+
+  const stream = new Pipeline()
+  index
+    .find(cache, key)
+    .then((entry) => {
+      if (!entry)
+        throw new index.NotFoundError(cache, key)
+
+      stream.emit('metadata', entry.metadata)
+      stream.emit('integrity', entry.integrity)
+      stream.emit('size', entry.size)
+      stream.on('newListener', function (ev, cb) {
+        ev === 'metadata' && cb(entry.metadata)
+        ev === 'integrity' && cb(entry.integrity)
+        ev === 'size' && cb(entry.size)
+      })
+
+      const src = read.readStream(
+        cache,
+        entry.integrity,
+        { ...opts, size: typeof size !== 'number' ? entry.size : size }
+      )
+
+      if (memoize) {
+        const memoStream = new Collect.PassThrough()
+        memoStream.on('collect', data => memo.put(cache, entry, data, opts))
+        stream.unshift(memoStream)
+      }
+      stream.unshift(src)
+    })
+    .catch((err) => stream.emit('error', err))
+
+  return stream
+}
+
+module.exports.stream = getStream
+
+function getStreamDigest (cache, integrity, opts = {}) {
+  const { memoize } = opts
+  const memoized = memo.get.byDigest(cache, integrity, opts)
+  if (memoized && memoize !== false) {
+    const stream = new Minipass()
+    stream.end(memoized)
+    return stream
+  } else {
+    const stream = read.readStream(cache, integrity, opts)
+    if (!memoize)
+      return stream
+
+    const memoStream = new Collect.PassThrough()
+    memoStream.on('collect', data => memo.put.byDigest(
+      cache,
+      integrity,
+      data,
+      opts
+    ))
+    return new Pipeline(stream, memoStream)
+  }
+}
+
+module.exports.stream.byDigest = getStreamDigest
+
+function info (cache, key, opts = {}) {
+  const { memoize } = opts
+  const memoized = memo.get(cache, key, opts)
+  if (memoized && memoize !== false)
+    return Promise.resolve(memoized.entry)
+  else
+    return index.find(cache, key)
+}
+module.exports.info = info
+
+function copy (cache, key, dest, opts = {}) {
+  if (read.copy) {
+    return index.find(cache, key, opts).then((entry) => {
+      if (!entry)
+        throw new index.NotFoundError(cache, key)
+      return read.copy(cache, entry.integrity, dest, opts)
+        .then(() => {
+          return {
+            metadata: entry.metadata,
+            size: entry.size,
+            integrity: entry.integrity,
+          }
+        })
+    })
+  }
+
+  return getData(cache, key, opts).then((res) => {
+    return writeFile(dest, res.data).then(() => {
+      return {
+        metadata: res.metadata,
+        size: res.size,
+        integrity: res.integrity,
+      }
+    })
+  })
+}
+module.exports.copy = copy
+
+function copyByDigest (cache, key, dest, opts = {}) {
+  if (read.copy)
+    return read.copy(cache, key, dest, opts).then(() => key)
+
+  return getDataByDigest(cache, key, opts).then((res) => {
+    return writeFile(dest, res).then(() => key)
+  })
+}
+module.exports.copy.byDigest = copyByDigest
+
+module.exports.hasContent = read.hasContent
diff --git a/server/node_modules/cacache/index.js b/server/node_modules/cacache/index.js
new file mode 100644
index 0000000..c8c52b0
--- /dev/null
+++ b/server/node_modules/cacache/index.js
@@ -0,0 +1,46 @@
+'use strict'
+
+const ls = require('./ls.js')
+const get = require('./get.js')
+const put = require('./put.js')
+const rm = require('./rm.js')
+const verify = require('./verify.js')
+const { clearMemoized } = require('./lib/memoization.js')
+const tmp = require('./lib/util/tmp.js')
+const index = require('./lib/entry-index.js')
+
+module.exports.index = {}
+module.exports.index.compact = index.compact
+module.exports.index.insert = index.insert
+
+module.exports.ls = ls
+module.exports.ls.stream = ls.stream
+
+module.exports.get = get
+module.exports.get.byDigest = get.byDigest
+module.exports.get.sync = get.sync
+module.exports.get.sync.byDigest = get.sync.byDigest
+module.exports.get.stream = get.stream
+module.exports.get.stream.byDigest = get.stream.byDigest
+module.exports.get.copy = get.copy
+module.exports.get.copy.byDigest = get.copy.byDigest
+module.exports.get.info = get.info
+module.exports.get.hasContent = get.hasContent
+module.exports.get.hasContent.sync = get.hasContent.sync
+
+module.exports.put = put
+module.exports.put.stream = put.stream
+
+module.exports.rm = rm.entry
+module.exports.rm.all = rm.all
+module.exports.rm.entry = module.exports.rm
+module.exports.rm.content = rm.content
+
+module.exports.clearMemoized = clearMemoized
+
+module.exports.tmp = {}
+module.exports.tmp.mkdir = tmp.mkdir
+module.exports.tmp.withTmp = tmp.withTmp
+
+module.exports.verify = verify
+module.exports.verify.lastRun = verify.lastRun
diff --git a/server/node_modules/cacache/lib/content/path.js b/server/node_modules/cacache/lib/content/path.js
new file mode 100644
index 0000000..ad5a76a
--- /dev/null
+++ b/server/node_modules/cacache/lib/content/path.js
@@ -0,0 +1,29 @@
+'use strict'
+
+const contentVer = require('../../package.json')['cache-version'].content
+const hashToSegments = require('../util/hash-to-segments')
+const path = require('path')
+const ssri = require('ssri')
+
+// Current format of content file path:
+//
+// sha512-BaSE64Hex= ->
+// ~/.my-cache/content-v2/sha512/ba/da/55deadbeefc0ffee
+//
+module.exports = contentPath
+
+function contentPath (cache, integrity) {
+  const sri = ssri.parse(integrity, { single: true })
+  // contentPath is the *strongest* algo given
+  return path.join(
+    contentDir(cache),
+    sri.algorithm,
+    ...hashToSegments(sri.hexDigest())
+  )
+}
+
+module.exports.contentDir = contentDir
+
+function contentDir (cache) {
+  return path.join(cache, `content-v${contentVer}`)
+}
diff --git a/server/node_modules/cacache/lib/content/read.js b/server/node_modules/cacache/lib/content/read.js
new file mode 100644
index 0000000..034e8ee
--- /dev/null
+++ b/server/node_modules/cacache/lib/content/read.js
@@ -0,0 +1,244 @@
+'use strict'
+
+const util = require('util')
+
+const fs = require('fs')
+const fsm = require('fs-minipass')
+const ssri = require('ssri')
+const contentPath = require('./path')
+const Pipeline = require('minipass-pipeline')
+
+const lstat = util.promisify(fs.lstat)
+const readFile = util.promisify(fs.readFile)
+
+module.exports = read
+
+const MAX_SINGLE_READ_SIZE = 64 * 1024 * 1024
+function read (cache, integrity, opts = {}) {
+  const { size } = opts
+  return withContentSri(cache, integrity, (cpath, sri) => {
+    // get size
+    return lstat(cpath).then(stat => ({ stat, cpath, sri }))
+  }).then(({ stat, cpath, sri }) => {
+    if (typeof size === 'number' && stat.size !== size)
+      throw sizeError(size, stat.size)
+
+    if (stat.size > MAX_SINGLE_READ_SIZE)
+      return readPipeline(cpath, stat.size, sri, new Pipeline()).concat()
+
+    return readFile(cpath, null).then((data) => {
+      if (!ssri.checkData(data, sri))
+        throw integrityError(sri, cpath)
+
+      return data
+    })
+  })
+}
+
+const readPipeline = (cpath, size, sri, stream) => {
+  stream.push(
+    new fsm.ReadStream(cpath, {
+      size,
+      readSize: MAX_SINGLE_READ_SIZE,
+    }),
+    ssri.integrityStream({
+      integrity: sri,
+      size,
+    })
+  )
+  return stream
+}
+
+module.exports.sync = readSync
+
+function readSync (cache, integrity, opts = {}) {
+  const { size } = opts
+  return withContentSriSync(cache, integrity, (cpath, sri) => {
+    const data = fs.readFileSync(cpath)
+    if (typeof size === 'number' && size !== data.length)
+      throw sizeError(size, data.length)
+
+    if (ssri.checkData(data, sri))
+      return data
+
+    throw integrityError(sri, cpath)
+  })
+}
+
+module.exports.stream = readStream
+module.exports.readStream = readStream
+
+function readStream (cache, integrity, opts = {}) {
+  const { size } = opts
+  const stream = new Pipeline()
+  withContentSri(cache, integrity, (cpath, sri) => {
+    // just lstat to ensure it exists
+    return lstat(cpath).then((stat) => ({ stat, cpath, sri }))
+  }).then(({ stat, cpath, sri }) => {
+    if (typeof size === 'number' && size !== stat.size)
+      return stream.emit('error', sizeError(size, stat.size))
+
+    readPipeline(cpath, stat.size, sri, stream)
+  }, er => stream.emit('error', er))
+
+  return stream
+}
+
+let copyFile
+if (fs.copyFile) {
+  module.exports.copy = copy
+  module.exports.copy.sync = copySync
+  copyFile = util.promisify(fs.copyFile)
+}
+
+function copy (cache, integrity, dest) {
+  return withContentSri(cache, integrity, (cpath, sri) => {
+    return copyFile(cpath, dest)
+  })
+}
+
+function copySync (cache, integrity, dest) {
+  return withContentSriSync(cache, integrity, (cpath, sri) => {
+    return fs.copyFileSync(cpath, dest)
+  })
+}
+
+module.exports.hasContent = hasContent
+
+function hasContent (cache, integrity) {
+  if (!integrity)
+    return Promise.resolve(false)
+
+  return withContentSri(cache, integrity, (cpath, sri) => {
+    return lstat(cpath).then((stat) => ({ size: stat.size, sri, stat }))
+  }).catch((err) => {
+    if (err.code === 'ENOENT')
+      return false
+
+    if (err.code === 'EPERM') {
+      /* istanbul ignore else */
+      if (process.platform !== 'win32')
+        throw err
+      else
+        return false
+    }
+  })
+}
+
+module.exports.hasContent.sync = hasContentSync
+
+function hasContentSync (cache, integrity) {
+  if (!integrity)
+    return false
+
+  return withContentSriSync(cache, integrity, (cpath, sri) => {
+    try {
+      const stat = fs.lstatSync(cpath)
+      return { size: stat.size, sri, stat }
+    } catch (err) {
+      if (err.code === 'ENOENT')
+        return false
+
+      if (err.code === 'EPERM') {
+        /* istanbul ignore else */
+        if (process.platform !== 'win32')
+          throw err
+        else
+          return false
+      }
+    }
+  })
+}
+
+function withContentSri (cache, integrity, fn) {
+  const tryFn = () => {
+    const sri = ssri.parse(integrity)
+    // If `integrity` has multiple entries, pick the first digest
+    // with available local data.
+    const algo = sri.pickAlgorithm()
+    const digests = sri[algo]
+
+    if (digests.length <= 1) {
+      const cpath = contentPath(cache, digests[0])
+      return fn(cpath, digests[0])
+    } else {
+      // Can't use race here because a generic error can happen before
+      // a ENOENT error, and can happen before a valid result
+      return Promise
+        .all(digests.map((meta) => {
+          return withContentSri(cache, meta, fn)
+            .catch((err) => {
+              if (err.code === 'ENOENT') {
+                return Object.assign(
+                  new Error('No matching content found for ' + sri.toString()),
+                  { code: 'ENOENT' }
+                )
+              }
+              return err
+            })
+        }))
+        .then((results) => {
+          // Return the first non error if it is found
+          const result = results.find((r) => !(r instanceof Error))
+          if (result)
+            return result
+
+          // Throw the No matching content found error
+          const enoentError = results.find((r) => r.code === 'ENOENT')
+          if (enoentError)
+            throw enoentError
+
+          // Throw generic error
+          throw results.find((r) => r instanceof Error)
+        })
+    }
+  }
+
+  return new Promise((resolve, reject) => {
+    try {
+      tryFn()
+        .then(resolve)
+        .catch(reject)
+    } catch (err) {
+      reject(err)
+    }
+  })
+}
+
+function withContentSriSync (cache, integrity, fn) {
+  const sri = ssri.parse(integrity)
+  // If `integrity` has multiple entries, pick the first digest
+  // with available local data.
+  const algo = sri.pickAlgorithm()
+  const digests = sri[algo]
+  if (digests.length <= 1) {
+    const cpath = contentPath(cache, digests[0])
+    return fn(cpath, digests[0])
+  } else {
+    let lastErr = null
+    for (const meta of digests) {
+      try {
+        return withContentSriSync(cache, meta, fn)
+      } catch (err) {
+        lastErr = err
+      }
+    }
+    throw lastErr
+  }
+}
+
+function sizeError (expected, found) {
+  const err = new Error(`Bad data size: expected inserted data to be ${expected} bytes, but got ${found} instead`)
+  err.expected = expected
+  err.found = found
+  err.code = 'EBADSIZE'
+  return err
+}
+
+function integrityError (sri, path) {
+  const err = new Error(`Integrity verification failed for ${sri} (${path})`)
+  err.code = 'EINTEGRITY'
+  err.sri = sri
+  err.path = path
+  return err
+}
diff --git a/server/node_modules/cacache/lib/content/rm.js b/server/node_modules/cacache/lib/content/rm.js
new file mode 100644
index 0000000..6a3d1a3
--- /dev/null
+++ b/server/node_modules/cacache/lib/content/rm.js
@@ -0,0 +1,19 @@
+'use strict'
+
+const util = require('util')
+
+const contentPath = require('./path')
+const { hasContent } = require('./read')
+const rimraf = util.promisify(require('rimraf'))
+
+module.exports = rm
+
+function rm (cache, integrity) {
+  return hasContent(cache, integrity).then((content) => {
+    // ~pretty~ sure we can't end up with a content lacking sri, but be safe
+    if (content && content.sri)
+      return rimraf(contentPath(cache, content.sri)).then(() => true)
+    else
+      return false
+  })
+}
diff --git a/server/node_modules/cacache/lib/content/write.js b/server/node_modules/cacache/lib/content/write.js
new file mode 100644
index 0000000..dde1bd1
--- /dev/null
+++ b/server/node_modules/cacache/lib/content/write.js
@@ -0,0 +1,189 @@
+'use strict'
+
+const util = require('util')
+
+const contentPath = require('./path')
+const fixOwner = require('../util/fix-owner')
+const fs = require('fs')
+const moveFile = require('../util/move-file')
+const Minipass = require('minipass')
+const Pipeline = require('minipass-pipeline')
+const Flush = require('minipass-flush')
+const path = require('path')
+const rimraf = util.promisify(require('rimraf'))
+const ssri = require('ssri')
+const uniqueFilename = require('unique-filename')
+const { disposer } = require('./../util/disposer')
+const fsm = require('fs-minipass')
+
+const writeFile = util.promisify(fs.writeFile)
+
+module.exports = write
+
+function write (cache, data, opts = {}) {
+  const { algorithms, size, integrity } = opts
+  if (algorithms && algorithms.length > 1)
+    throw new Error('opts.algorithms only supports a single algorithm for now')
+
+  if (typeof size === 'number' && data.length !== size)
+    return Promise.reject(sizeError(size, data.length))
+
+  const sri = ssri.fromData(data, algorithms ? { algorithms } : {})
+  if (integrity && !ssri.checkData(data, integrity, opts))
+    return Promise.reject(checksumError(integrity, sri))
+
+  return disposer(makeTmp(cache, opts), makeTmpDisposer,
+    (tmp) => {
+      return writeFile(tmp.target, data, { flag: 'wx' })
+        .then(() => moveToDestination(tmp, cache, sri, opts))
+    })
+    .then(() => ({ integrity: sri, size: data.length }))
+}
+
+module.exports.stream = writeStream
+
+// writes proxied to the 'inputStream' that is passed to the Promise
+// 'end' is deferred until content is handled.
+class CacacheWriteStream extends Flush {
+  constructor (cache, opts) {
+    super()
+    this.opts = opts
+    this.cache = cache
+    this.inputStream = new Minipass()
+    this.inputStream.on('error', er => this.emit('error', er))
+    this.inputStream.on('drain', () => this.emit('drain'))
+    this.handleContentP = null
+  }
+
+  write (chunk, encoding, cb) {
+    if (!this.handleContentP) {
+      this.handleContentP = handleContent(
+        this.inputStream,
+        this.cache,
+        this.opts
+      )
+    }
+    return this.inputStream.write(chunk, encoding, cb)
+  }
+
+  flush (cb) {
+    this.inputStream.end(() => {
+      if (!this.handleContentP) {
+        const e = new Error('Cache input stream was empty')
+        e.code = 'ENODATA'
+        // empty streams are probably emitting end right away.
+        // defer this one tick by rejecting a promise on it.
+        return Promise.reject(e).catch(cb)
+      }
+      this.handleContentP.then(
+        (res) => {
+          res.integrity && this.emit('integrity', res.integrity)
+          res.size !== null && this.emit('size', res.size)
+          cb()
+        },
+        (er) => cb(er)
+      )
+    })
+  }
+}
+
+function writeStream (cache, opts = {}) {
+  return new CacacheWriteStream(cache, opts)
+}
+
+function handleContent (inputStream, cache, opts) {
+  return disposer(makeTmp(cache, opts), makeTmpDisposer, (tmp) => {
+    return pipeToTmp(inputStream, cache, tmp.target, opts)
+      .then((res) => {
+        return moveToDestination(
+          tmp,
+          cache,
+          res.integrity,
+          opts
+        ).then(() => res)
+      })
+  })
+}
+
+function pipeToTmp (inputStream, cache, tmpTarget, opts) {
+  let integrity
+  let size
+  const hashStream = ssri.integrityStream({
+    integrity: opts.integrity,
+    algorithms: opts.algorithms,
+    size: opts.size,
+  })
+  hashStream.on('integrity', i => {
+    integrity = i
+  })
+  hashStream.on('size', s => {
+    size = s
+  })
+
+  const outStream = new fsm.WriteStream(tmpTarget, {
+    flags: 'wx',
+  })
+
+  // NB: this can throw if the hashStream has a problem with
+  // it, and the data is fully written.  but pipeToTmp is only
+  // called in promisory contexts where that is handled.
+  const pipeline = new Pipeline(
+    inputStream,
+    hashStream,
+    outStream
+  )
+
+  return pipeline.promise()
+    .then(() => ({ integrity, size }))
+    .catch(er => rimraf(tmpTarget).then(() => {
+      throw er
+    }))
+}
+
+function makeTmp (cache, opts) {
+  const tmpTarget = uniqueFilename(path.join(cache, 'tmp'), opts.tmpPrefix)
+  return fixOwner.mkdirfix(cache, path.dirname(tmpTarget)).then(() => ({
+    target: tmpTarget,
+    moved: false,
+  }))
+}
+
+function makeTmpDisposer (tmp) {
+  if (tmp.moved)
+    return Promise.resolve()
+
+  return rimraf(tmp.target)
+}
+
+function moveToDestination (tmp, cache, sri, opts) {
+  const destination = contentPath(cache, sri)
+  const destDir = path.dirname(destination)
+
+  return fixOwner
+    .mkdirfix(cache, destDir)
+    .then(() => {
+      return moveFile(tmp.target, destination)
+    })
+    .then(() => {
+      tmp.moved = true
+      return fixOwner.chownr(cache, destination)
+    })
+}
+
+function sizeError (expected, found) {
+  const err = new Error(`Bad data size: expected inserted data to be ${expected} bytes, but got ${found} instead`)
+  err.expected = expected
+  err.found = found
+  err.code = 'EBADSIZE'
+  return err
+}
+
+function checksumError (expected, found) {
+  const err = new Error(`Integrity check failed:
+  Wanted: ${expected}
+   Found: ${found}`)
+  err.code = 'EINTEGRITY'
+  err.expected = expected
+  err.found = found
+  return err
+}
diff --git a/server/node_modules/cacache/lib/entry-index.js b/server/node_modules/cacache/lib/entry-index.js
new file mode 100644
index 0000000..71aac5e
--- /dev/null
+++ b/server/node_modules/cacache/lib/entry-index.js
@@ -0,0 +1,394 @@
+'use strict'
+
+const util = require('util')
+const crypto = require('crypto')
+const fs = require('fs')
+const Minipass = require('minipass')
+const path = require('path')
+const ssri = require('ssri')
+const uniqueFilename = require('unique-filename')
+
+const { disposer } = require('./util/disposer')
+const contentPath = require('./content/path')
+const fixOwner = require('./util/fix-owner')
+const hashToSegments = require('./util/hash-to-segments')
+const indexV = require('../package.json')['cache-version'].index
+const moveFile = require('@npmcli/move-file')
+const _rimraf = require('rimraf')
+const rimraf = util.promisify(_rimraf)
+rimraf.sync = _rimraf.sync
+
+const appendFile = util.promisify(fs.appendFile)
+const readFile = util.promisify(fs.readFile)
+const readdir = util.promisify(fs.readdir)
+const writeFile = util.promisify(fs.writeFile)
+
+module.exports.NotFoundError = class NotFoundError extends Error {
+  constructor (cache, key) {
+    super(`No cache entry for ${key} found in ${cache}`)
+    this.code = 'ENOENT'
+    this.cache = cache
+    this.key = key
+  }
+}
+
+module.exports.compact = compact
+
+async function compact (cache, key, matchFn, opts = {}) {
+  const bucket = bucketPath(cache, key)
+  const entries = await bucketEntries(bucket)
+  const newEntries = []
+  // we loop backwards because the bottom-most result is the newest
+  // since we add new entries with appendFile
+  for (let i = entries.length - 1; i >= 0; --i) {
+    const entry = entries[i]
+    // a null integrity could mean either a delete was appended
+    // or the user has simply stored an index that does not map
+    // to any content. we determine if the user wants to keep the
+    // null integrity based on the validateEntry function passed in options.
+    // if the integrity is null and no validateEntry is provided, we break
+    // as we consider the null integrity to be a deletion of everything
+    // that came before it.
+    if (entry.integrity === null && !opts.validateEntry)
+      break
+
+    // if this entry is valid, and it is either the first entry or
+    // the newEntries array doesn't already include an entry that
+    // matches this one based on the provided matchFn, then we add
+    // it to the beginning of our list
+    if ((!opts.validateEntry || opts.validateEntry(entry) === true) &&
+      (newEntries.length === 0 ||
+        !newEntries.find((oldEntry) => matchFn(oldEntry, entry))))
+      newEntries.unshift(entry)
+  }
+
+  const newIndex = '\n' + newEntries.map((entry) => {
+    const stringified = JSON.stringify(entry)
+    const hash = hashEntry(stringified)
+    return `${hash}\t${stringified}`
+  }).join('\n')
+
+  const setup = async () => {
+    const target = uniqueFilename(path.join(cache, 'tmp'), opts.tmpPrefix)
+    await fixOwner.mkdirfix(cache, path.dirname(target))
+    return {
+      target,
+      moved: false,
+    }
+  }
+
+  const teardown = async (tmp) => {
+    if (!tmp.moved)
+      return rimraf(tmp.target)
+  }
+
+  const write = async (tmp) => {
+    await writeFile(tmp.target, newIndex, { flag: 'wx' })
+    await fixOwner.mkdirfix(cache, path.dirname(bucket))
+    // we use @npmcli/move-file directly here because we
+    // want to overwrite the existing file
+    await moveFile(tmp.target, bucket)
+    tmp.moved = true
+    try {
+      await fixOwner.chownr(cache, bucket)
+    } catch (err) {
+      if (err.code !== 'ENOENT')
+        throw err
+    }
+  }
+
+  // write the file atomically
+  await disposer(setup(), teardown, write)
+
+  // we reverse the list we generated such that the newest
+  // entries come first in order to make looping through them easier
+  // the true passed to formatEntry tells it to keep null
+  // integrity values, if they made it this far it's because
+  // validateEntry returned true, and as such we should return it
+  return newEntries.reverse().map((entry) => formatEntry(cache, entry, true))
+}
+
+module.exports.insert = insert
+
+function insert (cache, key, integrity, opts = {}) {
+  const { metadata, size } = opts
+  const bucket = bucketPath(cache, key)
+  const entry = {
+    key,
+    integrity: integrity && ssri.stringify(integrity),
+    time: Date.now(),
+    size,
+    metadata,
+  }
+  return fixOwner
+    .mkdirfix(cache, path.dirname(bucket))
+    .then(() => {
+      const stringified = JSON.stringify(entry)
+      // NOTE - Cleverness ahoy!
+      //
+      // This works because it's tremendously unlikely for an entry to corrupt
+      // another while still preserving the string length of the JSON in
+      // question. So, we just slap the length in there and verify it on read.
+      //
+      // Thanks to @isaacs for the whiteboarding session that ended up with
+      // this.
+      return appendFile(bucket, `\n${hashEntry(stringified)}\t${stringified}`)
+    })
+    .then(() => fixOwner.chownr(cache, bucket))
+    .catch((err) => {
+      if (err.code === 'ENOENT')
+        return undefined
+
+      throw err
+      // There's a class of race conditions that happen when things get deleted
+      // during fixOwner, or between the two mkdirfix/chownr calls.
+      //
+      // It's perfectly fine to just not bother in those cases and lie
+      // that the index entry was written. Because it's a cache.
+    })
+    .then(() => {
+      return formatEntry(cache, entry)
+    })
+}
+
+module.exports.insert.sync = insertSync
+
+function insertSync (cache, key, integrity, opts = {}) {
+  const { metadata, size } = opts
+  const bucket = bucketPath(cache, key)
+  const entry = {
+    key,
+    integrity: integrity && ssri.stringify(integrity),
+    time: Date.now(),
+    size,
+    metadata,
+  }
+  fixOwner.mkdirfix.sync(cache, path.dirname(bucket))
+  const stringified = JSON.stringify(entry)
+  fs.appendFileSync(bucket, `\n${hashEntry(stringified)}\t${stringified}`)
+  try {
+    fixOwner.chownr.sync(cache, bucket)
+  } catch (err) {
+    if (err.code !== 'ENOENT')
+      throw err
+  }
+  return formatEntry(cache, entry)
+}
+
+module.exports.find = find
+
+function find (cache, key) {
+  const bucket = bucketPath(cache, key)
+  return bucketEntries(bucket)
+    .then((entries) => {
+      return entries.reduce((latest, next) => {
+        if (next && next.key === key)
+          return formatEntry(cache, next)
+        else
+          return latest
+      }, null)
+    })
+    .catch((err) => {
+      if (err.code === 'ENOENT')
+        return null
+      else
+        throw err
+    })
+}
+
+module.exports.find.sync = findSync
+
+function findSync (cache, key) {
+  const bucket = bucketPath(cache, key)
+  try {
+    return bucketEntriesSync(bucket).reduce((latest, next) => {
+      if (next && next.key === key)
+        return formatEntry(cache, next)
+      else
+        return latest
+    }, null)
+  } catch (err) {
+    if (err.code === 'ENOENT')
+      return null
+    else
+      throw err
+  }
+}
+
+module.exports.delete = del
+
+function del (cache, key, opts = {}) {
+  if (!opts.removeFully)
+    return insert(cache, key, null, opts)
+
+  const bucket = bucketPath(cache, key)
+  return rimraf(bucket)
+}
+
+module.exports.delete.sync = delSync
+
+function delSync (cache, key, opts = {}) {
+  if (!opts.removeFully)
+    return insertSync(cache, key, null, opts)
+
+  const bucket = bucketPath(cache, key)
+  return rimraf.sync(bucket)
+}
+
+module.exports.lsStream = lsStream
+
+function lsStream (cache) {
+  const indexDir = bucketDir(cache)
+  const stream = new Minipass({ objectMode: true })
+
+  readdirOrEmpty(indexDir).then(buckets => Promise.all(
+    buckets.map(bucket => {
+      const bucketPath = path.join(indexDir, bucket)
+      return readdirOrEmpty(bucketPath).then(subbuckets => Promise.all(
+        subbuckets.map(subbucket => {
+          const subbucketPath = path.join(bucketPath, subbucket)
+
+          // "/cachename/<bucket 0xFF>/<bucket 0xFF>./*"
+          return readdirOrEmpty(subbucketPath).then(entries => Promise.all(
+            entries.map(entry => {
+              const entryPath = path.join(subbucketPath, entry)
+              return bucketEntries(entryPath).then(entries =>
+                // using a Map here prevents duplicate keys from
+                // showing up twice, I guess?
+                entries.reduce((acc, entry) => {
+                  acc.set(entry.key, entry)
+                  return acc
+                }, new Map())
+              ).then(reduced => {
+                // reduced is a map of key => entry
+                for (const entry of reduced.values()) {
+                  const formatted = formatEntry(cache, entry)
+                  if (formatted)
+                    stream.write(formatted)
+                }
+              }).catch(err => {
+                if (err.code === 'ENOENT')
+                  return undefined
+                throw err
+              })
+            })
+          ))
+        })
+      ))
+    })
+  ))
+    .then(
+      () => stream.end(),
+      err => stream.emit('error', err)
+    )
+
+  return stream
+}
+
+module.exports.ls = ls
+
+function ls (cache) {
+  return lsStream(cache).collect().then(entries =>
+    entries.reduce((acc, xs) => {
+      acc[xs.key] = xs
+      return acc
+    }, {})
+  )
+}
+
+module.exports.bucketEntries = bucketEntries
+
+function bucketEntries (bucket, filter) {
+  return readFile(bucket, 'utf8').then((data) => _bucketEntries(data, filter))
+}
+
+module.exports.bucketEntries.sync = bucketEntriesSync
+
+function bucketEntriesSync (bucket, filter) {
+  const data = fs.readFileSync(bucket, 'utf8')
+  return _bucketEntries(data, filter)
+}
+
+function _bucketEntries (data, filter) {
+  const entries = []
+  data.split('\n').forEach((entry) => {
+    if (!entry)
+      return
+
+    const pieces = entry.split('\t')
+    if (!pieces[1] || hashEntry(pieces[1]) !== pieces[0]) {
+      // Hash is no good! Corruption or malice? Doesn't matter!
+      // EJECT EJECT
+      return
+    }
+    let obj
+    try {
+      obj = JSON.parse(pieces[1])
+    } catch (e) {
+      // Entry is corrupted!
+      return
+    }
+    if (obj)
+      entries.push(obj)
+  })
+  return entries
+}
+
+module.exports.bucketDir = bucketDir
+
+function bucketDir (cache) {
+  return path.join(cache, `index-v${indexV}`)
+}
+
+module.exports.bucketPath = bucketPath
+
+function bucketPath (cache, key) {
+  const hashed = hashKey(key)
+  return path.join.apply(
+    path,
+    [bucketDir(cache)].concat(hashToSegments(hashed))
+  )
+}
+
+module.exports.hashKey = hashKey
+
+function hashKey (key) {
+  return hash(key, 'sha256')
+}
+
+module.exports.hashEntry = hashEntry
+
+function hashEntry (str) {
+  return hash(str, 'sha1')
+}
+
+function hash (str, digest) {
+  return crypto
+    .createHash(digest)
+    .update(str)
+    .digest('hex')
+}
+
+function formatEntry (cache, entry, keepAll) {
+  // Treat null digests as deletions. They'll shadow any previous entries.
+  if (!entry.integrity && !keepAll)
+    return null
+
+  return {
+    key: entry.key,
+    integrity: entry.integrity,
+    path: entry.integrity ? contentPath(cache, entry.integrity) : undefined,
+    size: entry.size,
+    time: entry.time,
+    metadata: entry.metadata,
+  }
+}
+
+function readdirOrEmpty (dir) {
+  return readdir(dir).catch((err) => {
+    if (err.code === 'ENOENT' || err.code === 'ENOTDIR')
+      return []
+
+    throw err
+  })
+}
diff --git a/server/node_modules/cacache/lib/memoization.js b/server/node_modules/cacache/lib/memoization.js
new file mode 100644
index 0000000..d5465f3
--- /dev/null
+++ b/server/node_modules/cacache/lib/memoization.js
@@ -0,0 +1,73 @@
+'use strict'
+
+const LRU = require('lru-cache')
+
+const MAX_SIZE = 50 * 1024 * 1024 // 50MB
+const MAX_AGE = 3 * 60 * 1000
+
+const MEMOIZED = new LRU({
+  max: MAX_SIZE,
+  maxAge: MAX_AGE,
+  length: (entry, key) => key.startsWith('key:') ? entry.data.length : entry.length,
+})
+
+module.exports.clearMemoized = clearMemoized
+
+function clearMemoized () {
+  const old = {}
+  MEMOIZED.forEach((v, k) => {
+    old[k] = v
+  })
+  MEMOIZED.reset()
+  return old
+}
+
+module.exports.put = put
+
+function put (cache, entry, data, opts) {
+  pickMem(opts).set(`key:${cache}:${entry.key}`, { entry, data })
+  putDigest(cache, entry.integrity, data, opts)
+}
+
+module.exports.put.byDigest = putDigest
+
+function putDigest (cache, integrity, data, opts) {
+  pickMem(opts).set(`digest:${cache}:${integrity}`, data)
+}
+
+module.exports.get = get
+
+function get (cache, key, opts) {
+  return pickMem(opts).get(`key:${cache}:${key}`)
+}
+
+module.exports.get.byDigest = getDigest
+
+function getDigest (cache, integrity, opts) {
+  return pickMem(opts).get(`digest:${cache}:${integrity}`)
+}
+
+class ObjProxy {
+  constructor (obj) {
+    this.obj = obj
+  }
+
+  get (key) {
+    return this.obj[key]
+  }
+
+  set (key, val) {
+    this.obj[key] = val
+  }
+}
+
+function pickMem (opts) {
+  if (!opts || !opts.memoize)
+    return MEMOIZED
+  else if (opts.memoize.get && opts.memoize.set)
+    return opts.memoize
+  else if (typeof opts.memoize === 'object')
+    return new ObjProxy(opts.memoize)
+  else
+    return MEMOIZED
+}
diff --git a/server/node_modules/cacache/lib/util/disposer.js b/server/node_modules/cacache/lib/util/disposer.js
new file mode 100644
index 0000000..aa8aed5
--- /dev/null
+++ b/server/node_modules/cacache/lib/util/disposer.js
@@ -0,0 +1,30 @@
+'use strict'
+
+module.exports.disposer = disposer
+
+function disposer (creatorFn, disposerFn, fn) {
+  const runDisposer = (resource, result, shouldThrow = false) => {
+    return disposerFn(resource)
+      .then(
+        // disposer resolved, do something with original fn's promise
+        () => {
+          if (shouldThrow)
+            throw result
+
+          return result
+        },
+        // Disposer fn failed, crash process
+        (err) => {
+          throw err
+          // Or process.exit?
+        })
+  }
+
+  return creatorFn
+    .then((resource) => {
+      // fn(resource) can throw, so wrap in a promise here
+      return Promise.resolve().then(() => fn(resource))
+        .then((result) => runDisposer(resource, result))
+        .catch((err) => runDisposer(resource, err, true))
+    })
+}
diff --git a/server/node_modules/cacache/lib/util/fix-owner.js b/server/node_modules/cacache/lib/util/fix-owner.js
new file mode 100644
index 0000000..90ffece
--- /dev/null
+++ b/server/node_modules/cacache/lib/util/fix-owner.js
@@ -0,0 +1,142 @@
+'use strict'
+
+const util = require('util')
+
+const chownr = util.promisify(require('chownr'))
+const mkdirp = require('mkdirp')
+const inflight = require('promise-inflight')
+const inferOwner = require('infer-owner')
+
+// Memoize getuid()/getgid() calls.
+// patch process.setuid/setgid to invalidate cached value on change
+const self = { uid: null, gid: null }
+const getSelf = () => {
+  if (typeof self.uid !== 'number') {
+    self.uid = process.getuid()
+    const setuid = process.setuid
+    process.setuid = (uid) => {
+      self.uid = null
+      process.setuid = setuid
+      return process.setuid(uid)
+    }
+  }
+  if (typeof self.gid !== 'number') {
+    self.gid = process.getgid()
+    const setgid = process.setgid
+    process.setgid = (gid) => {
+      self.gid = null
+      process.setgid = setgid
+      return process.setgid(gid)
+    }
+  }
+}
+
+module.exports.chownr = fixOwner
+
+function fixOwner (cache, filepath) {
+  if (!process.getuid) {
+    // This platform doesn't need ownership fixing
+    return Promise.resolve()
+  }
+
+  getSelf()
+  if (self.uid !== 0) {
+    // almost certainly can't chown anyway
+    return Promise.resolve()
+  }
+
+  return Promise.resolve(inferOwner(cache)).then((owner) => {
+    const { uid, gid } = owner
+
+    // No need to override if it's already what we used.
+    if (self.uid === uid && self.gid === gid)
+      return
+
+    return inflight('fixOwner: fixing ownership on ' + filepath, () =>
+      chownr(
+        filepath,
+        typeof uid === 'number' ? uid : self.uid,
+        typeof gid === 'number' ? gid : self.gid
+      ).catch((err) => {
+        if (err.code === 'ENOENT')
+          return null
+
+        throw err
+      })
+    )
+  })
+}
+
+module.exports.chownr.sync = fixOwnerSync
+
+function fixOwnerSync (cache, filepath) {
+  if (!process.getuid) {
+    // This platform doesn't need ownership fixing
+    return
+  }
+  const { uid, gid } = inferOwner.sync(cache)
+  getSelf()
+  if (self.uid !== 0) {
+    // almost certainly can't chown anyway
+    return
+  }
+
+  if (self.uid === uid && self.gid === gid) {
+    // No need to override if it's already what we used.
+    return
+  }
+  try {
+    chownr.sync(
+      filepath,
+      typeof uid === 'number' ? uid : self.uid,
+      typeof gid === 'number' ? gid : self.gid
+    )
+  } catch (err) {
+    // only catch ENOENT, any other error is a problem.
+    if (err.code === 'ENOENT')
+      return null
+
+    throw err
+  }
+}
+
+module.exports.mkdirfix = mkdirfix
+
+function mkdirfix (cache, p, cb) {
+  // we have to infer the owner _before_ making the directory, even though
+  // we aren't going to use the results, since the cache itself might not
+  // exist yet.  If we mkdirp it, then our current uid/gid will be assumed
+  // to be correct if it creates the cache folder in the process.
+  return Promise.resolve(inferOwner(cache)).then(() => {
+    return mkdirp(p)
+      .then((made) => {
+        if (made)
+          return fixOwner(cache, made).then(() => made)
+      })
+      .catch((err) => {
+        if (err.code === 'EEXIST')
+          return fixOwner(cache, p).then(() => null)
+
+        throw err
+      })
+  })
+}
+
+module.exports.mkdirfix.sync = mkdirfixSync
+
+function mkdirfixSync (cache, p) {
+  try {
+    inferOwner.sync(cache)
+    const made = mkdirp.sync(p)
+    if (made) {
+      fixOwnerSync(cache, made)
+      return made
+    }
+  } catch (err) {
+    if (err.code === 'EEXIST') {
+      fixOwnerSync(cache, p)
+      return null
+    } else
+      throw err
+  }
+}
diff --git a/server/node_modules/cacache/lib/util/hash-to-segments.js b/server/node_modules/cacache/lib/util/hash-to-segments.js
new file mode 100644
index 0000000..445599b
--- /dev/null
+++ b/server/node_modules/cacache/lib/util/hash-to-segments.js
@@ -0,0 +1,7 @@
+'use strict'
+
+module.exports = hashToSegments
+
+function hashToSegments (hash) {
+  return [hash.slice(0, 2), hash.slice(2, 4), hash.slice(4)]
+}
diff --git a/server/node_modules/cacache/lib/util/move-file.js b/server/node_modules/cacache/lib/util/move-file.js
new file mode 100644
index 0000000..c3f9e35
--- /dev/null
+++ b/server/node_modules/cacache/lib/util/move-file.js
@@ -0,0 +1,67 @@
+'use strict'
+
+const fs = require('fs')
+const util = require('util')
+const chmod = util.promisify(fs.chmod)
+const unlink = util.promisify(fs.unlink)
+const stat = util.promisify(fs.stat)
+const move = require('@npmcli/move-file')
+const pinflight = require('promise-inflight')
+
+module.exports = moveFile
+
+function moveFile (src, dest) {
+  const isWindows = global.__CACACHE_TEST_FAKE_WINDOWS__ ||
+    process.platform === 'win32'
+
+  // This isn't quite an fs.rename -- the assumption is that
+  // if `dest` already exists, and we get certain errors while
+  // trying to move it, we should just not bother.
+  //
+  // In the case of cache corruption, users will receive an
+  // EINTEGRITY error elsewhere, and can remove the offending
+  // content their own way.
+  //
+  // Note that, as the name suggests, this strictly only supports file moves.
+  return new Promise((resolve, reject) => {
+    fs.link(src, dest, (err) => {
+      if (err) {
+        if (isWindows && err.code === 'EPERM') {
+          // XXX This is a really weird way to handle this situation, as it
+          // results in the src file being deleted even though the dest
+          // might not exist.  Since we pretty much always write files to
+          // deterministic locations based on content hash, this is likely
+          // ok (or at worst, just ends in a future cache miss).  But it would
+          // be worth investigating at some time in the future if this is
+          // really what we want to do here.
+          return resolve()
+        } else if (err.code === 'EEXIST' || err.code === 'EBUSY') {
+          // file already exists, so whatever
+          return resolve()
+        } else
+          return reject(err)
+      } else
+        return resolve()
+    })
+  })
+    .then(() => {
+      // content should never change for any reason, so make it read-only
+      return Promise.all([
+        unlink(src),
+        !isWindows && chmod(dest, '0444'),
+      ])
+    })
+    .catch(() => {
+      return pinflight('cacache-move-file:' + dest, () => {
+        return stat(dest).catch((err) => {
+          if (err.code !== 'ENOENT') {
+            // Something else is wrong here. Bail bail bail
+            throw err
+          }
+          // file doesn't already exist! let's try a rename -> copy fallback
+          // only delete if it successfully copies
+          return move(src, dest)
+        })
+      })
+    })
+}
diff --git a/server/node_modules/cacache/lib/util/tmp.js b/server/node_modules/cacache/lib/util/tmp.js
new file mode 100644
index 0000000..0a5a50e
--- /dev/null
+++ b/server/node_modules/cacache/lib/util/tmp.js
@@ -0,0 +1,35 @@
+'use strict'
+
+const fs = require('@npmcli/fs')
+
+const fixOwner = require('./fix-owner')
+const path = require('path')
+
+module.exports.mkdir = mktmpdir
+
+function mktmpdir (cache, opts = {}) {
+  const { tmpPrefix } = opts
+  const tmpDir = path.join(cache, 'tmp')
+  return fs.mkdir(tmpDir, { recursive: true, owner: 'inherit' })
+    .then(() => {
+      // do not use path.join(), it drops the trailing / if tmpPrefix is unset
+      const target = `${tmpDir}${path.sep}${tmpPrefix || ''}`
+      return fs.mkdtemp(target, { owner: 'inherit' })
+    })
+}
+
+module.exports.withTmp = withTmp
+
+function withTmp (cache, opts, cb) {
+  if (!cb) {
+    cb = opts
+    opts = {}
+  }
+  return fs.withTempDir(path.join(cache, 'tmp'), cb, opts)
+}
+
+module.exports.fix = fixtmpdir
+
+function fixtmpdir (cache) {
+  return fixOwner(cache, path.join(cache, 'tmp'))
+}
diff --git a/server/node_modules/cacache/lib/verify.js b/server/node_modules/cacache/lib/verify.js
new file mode 100644
index 0000000..e9d679e
--- /dev/null
+++ b/server/node_modules/cacache/lib/verify.js
@@ -0,0 +1,287 @@
+'use strict'
+
+const util = require('util')
+
+const pMap = require('p-map')
+const contentPath = require('./content/path')
+const fixOwner = require('./util/fix-owner')
+const fs = require('fs')
+const fsm = require('fs-minipass')
+const glob = util.promisify(require('glob'))
+const index = require('./entry-index')
+const path = require('path')
+const rimraf = util.promisify(require('rimraf'))
+const ssri = require('ssri')
+
+const hasOwnProperty = (obj, key) =>
+  Object.prototype.hasOwnProperty.call(obj, key)
+
+const stat = util.promisify(fs.stat)
+const truncate = util.promisify(fs.truncate)
+const writeFile = util.promisify(fs.writeFile)
+const readFile = util.promisify(fs.readFile)
+
+const verifyOpts = (opts) => ({
+  concurrency: 20,
+  log: { silly () {} },
+  ...opts,
+})
+
+module.exports = verify
+
+function verify (cache, opts) {
+  opts = verifyOpts(opts)
+  opts.log.silly('verify', 'verifying cache at', cache)
+
+  const steps = [
+    markStartTime,
+    fixPerms,
+    garbageCollect,
+    rebuildIndex,
+    cleanTmp,
+    writeVerifile,
+    markEndTime,
+  ]
+
+  return steps
+    .reduce((promise, step, i) => {
+      const label = step.name
+      const start = new Date()
+      return promise.then((stats) => {
+        return step(cache, opts).then((s) => {
+          s &&
+            Object.keys(s).forEach((k) => {
+              stats[k] = s[k]
+            })
+          const end = new Date()
+          if (!stats.runTime)
+            stats.runTime = {}
+
+          stats.runTime[label] = end - start
+          return Promise.resolve(stats)
+        })
+      })
+    }, Promise.resolve({}))
+    .then((stats) => {
+      stats.runTime.total = stats.endTime - stats.startTime
+      opts.log.silly(
+        'verify',
+        'verification finished for',
+        cache,
+        'in',
+        `${stats.runTime.total}ms`
+      )
+      return stats
+    })
+}
+
+function markStartTime (cache, opts) {
+  return Promise.resolve({ startTime: new Date() })
+}
+
+function markEndTime (cache, opts) {
+  return Promise.resolve({ endTime: new Date() })
+}
+
+function fixPerms (cache, opts) {
+  opts.log.silly('verify', 'fixing cache permissions')
+  return fixOwner
+    .mkdirfix(cache, cache)
+    .then(() => {
+      // TODO - fix file permissions too
+      return fixOwner.chownr(cache, cache)
+    })
+    .then(() => null)
+}
+
+// Implements a naive mark-and-sweep tracing garbage collector.
+//
+// The algorithm is basically as follows:
+// 1. Read (and filter) all index entries ("pointers")
+// 2. Mark each integrity value as "live"
+// 3. Read entire filesystem tree in `content-vX/` dir
+// 4. If content is live, verify its checksum and delete it if it fails
+// 5. If content is not marked as live, rimraf it.
+//
+function garbageCollect (cache, opts) {
+  opts.log.silly('verify', 'garbage collecting content')
+  const indexStream = index.lsStream(cache)
+  const liveContent = new Set()
+  indexStream.on('data', (entry) => {
+    if (opts.filter && !opts.filter(entry))
+      return
+
+    liveContent.add(entry.integrity.toString())
+  })
+  return new Promise((resolve, reject) => {
+    indexStream.on('end', resolve).on('error', reject)
+  }).then(() => {
+    const contentDir = contentPath.contentDir(cache)
+    return glob(path.join(contentDir, '**'), {
+      follow: false,
+      nodir: true,
+      nosort: true,
+    }).then((files) => {
+      return Promise.resolve({
+        verifiedContent: 0,
+        reclaimedCount: 0,
+        reclaimedSize: 0,
+        badContentCount: 0,
+        keptSize: 0,
+      }).then((stats) =>
+        pMap(
+          files,
+          (f) => {
+            const split = f.split(/[/\\]/)
+            const digest = split.slice(split.length - 3).join('')
+            const algo = split[split.length - 4]
+            const integrity = ssri.fromHex(digest, algo)
+            if (liveContent.has(integrity.toString())) {
+              return verifyContent(f, integrity).then((info) => {
+                if (!info.valid) {
+                  stats.reclaimedCount++
+                  stats.badContentCount++
+                  stats.reclaimedSize += info.size
+                } else {
+                  stats.verifiedContent++
+                  stats.keptSize += info.size
+                }
+                return stats
+              })
+            } else {
+              // No entries refer to this content. We can delete.
+              stats.reclaimedCount++
+              return stat(f).then((s) => {
+                return rimraf(f).then(() => {
+                  stats.reclaimedSize += s.size
+                  return stats
+                })
+              })
+            }
+          },
+          { concurrency: opts.concurrency }
+        ).then(() => stats)
+      )
+    })
+  })
+}
+
+function verifyContent (filepath, sri) {
+  return stat(filepath)
+    .then((s) => {
+      const contentInfo = {
+        size: s.size,
+        valid: true,
+      }
+      return ssri
+        .checkStream(new fsm.ReadStream(filepath), sri)
+        .catch((err) => {
+          if (err.code !== 'EINTEGRITY')
+            throw err
+
+          return rimraf(filepath).then(() => {
+            contentInfo.valid = false
+          })
+        })
+        .then(() => contentInfo)
+    })
+    .catch((err) => {
+      if (err.code === 'ENOENT')
+        return { size: 0, valid: false }
+
+      throw err
+    })
+}
+
+function rebuildIndex (cache, opts) {
+  opts.log.silly('verify', 'rebuilding index')
+  return index.ls(cache).then((entries) => {
+    const stats = {
+      missingContent: 0,
+      rejectedEntries: 0,
+      totalEntries: 0,
+    }
+    const buckets = {}
+    for (const k in entries) {
+      /* istanbul ignore else */
+      if (hasOwnProperty(entries, k)) {
+        const hashed = index.hashKey(k)
+        const entry = entries[k]
+        const excluded = opts.filter && !opts.filter(entry)
+        excluded && stats.rejectedEntries++
+        if (buckets[hashed] && !excluded)
+          buckets[hashed].push(entry)
+        else if (buckets[hashed] && excluded) {
+          // skip
+        } else if (excluded) {
+          buckets[hashed] = []
+          buckets[hashed]._path = index.bucketPath(cache, k)
+        } else {
+          buckets[hashed] = [entry]
+          buckets[hashed]._path = index.bucketPath(cache, k)
+        }
+      }
+    }
+    return pMap(
+      Object.keys(buckets),
+      (key) => {
+        return rebuildBucket(cache, buckets[key], stats, opts)
+      },
+      { concurrency: opts.concurrency }
+    ).then(() => stats)
+  })
+}
+
+function rebuildBucket (cache, bucket, stats, opts) {
+  return truncate(bucket._path).then(() => {
+    // This needs to be serialized because cacache explicitly
+    // lets very racy bucket conflicts clobber each other.
+    return bucket.reduce((promise, entry) => {
+      return promise.then(() => {
+        const content = contentPath(cache, entry.integrity)
+        return stat(content)
+          .then(() => {
+            return index
+              .insert(cache, entry.key, entry.integrity, {
+                metadata: entry.metadata,
+                size: entry.size,
+              })
+              .then(() => {
+                stats.totalEntries++
+              })
+          })
+          .catch((err) => {
+            if (err.code === 'ENOENT') {
+              stats.rejectedEntries++
+              stats.missingContent++
+              return
+            }
+            throw err
+          })
+      })
+    }, Promise.resolve())
+  })
+}
+
+function cleanTmp (cache, opts) {
+  opts.log.silly('verify', 'cleaning tmp directory')
+  return rimraf(path.join(cache, 'tmp'))
+}
+
+function writeVerifile (cache, opts) {
+  const verifile = path.join(cache, '_lastverified')
+  opts.log.silly('verify', 'writing verifile to ' + verifile)
+  try {
+    return writeFile(verifile, '' + +new Date())
+  } finally {
+    fixOwner.chownr.sync(cache, verifile)
+  }
+}
+
+module.exports.lastRun = lastRun
+
+function lastRun (cache) {
+  return readFile(path.join(cache, '_lastverified'), 'utf8').then(
+    (data) => new Date(+data)
+  )
+}
diff --git a/server/node_modules/cacache/ls.js b/server/node_modules/cacache/ls.js
new file mode 100644
index 0000000..6006c99
--- /dev/null
+++ b/server/node_modules/cacache/ls.js
@@ -0,0 +1,6 @@
+'use strict'
+
+const index = require('./lib/entry-index')
+
+module.exports = index.ls
+module.exports.stream = index.lsStream
diff --git a/server/node_modules/cacache/node_modules/.bin/mkdirp b/server/node_modules/cacache/node_modules/.bin/mkdirp
new file mode 120000
index 0000000..017896c
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/.bin/mkdirp
@@ -0,0 +1 @@
+../mkdirp/bin/cmd.js
\ No newline at end of file
diff --git a/server/node_modules/cacache/node_modules/chownr/LICENSE b/server/node_modules/cacache/node_modules/chownr/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/chownr/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/cacache/node_modules/chownr/README.md b/server/node_modules/cacache/node_modules/chownr/README.md
new file mode 100644
index 0000000..70e9a54
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/chownr/README.md
@@ -0,0 +1,3 @@
+Like `chown -R`.
+
+Takes the same arguments as `fs.chown()`
diff --git a/server/node_modules/cacache/node_modules/chownr/chownr.js b/server/node_modules/cacache/node_modules/chownr/chownr.js
new file mode 100644
index 0000000..0d40932
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/chownr/chownr.js
@@ -0,0 +1,167 @@
+'use strict'
+const fs = require('fs')
+const path = require('path')
+
+/* istanbul ignore next */
+const LCHOWN = fs.lchown ? 'lchown' : 'chown'
+/* istanbul ignore next */
+const LCHOWNSYNC = fs.lchownSync ? 'lchownSync' : 'chownSync'
+
+/* istanbul ignore next */
+const needEISDIRHandled = fs.lchown &&
+  !process.version.match(/v1[1-9]+\./) &&
+  !process.version.match(/v10\.[6-9]/)
+
+const lchownSync = (path, uid, gid) => {
+  try {
+    return fs[LCHOWNSYNC](path, uid, gid)
+  } catch (er) {
+    if (er.code !== 'ENOENT')
+      throw er
+  }
+}
+
+/* istanbul ignore next */
+const chownSync = (path, uid, gid) => {
+  try {
+    return fs.chownSync(path, uid, gid)
+  } catch (er) {
+    if (er.code !== 'ENOENT')
+      throw er
+  }
+}
+
+/* istanbul ignore next */
+const handleEISDIR =
+  needEISDIRHandled ? (path, uid, gid, cb) => er => {
+    // Node prior to v10 had a very questionable implementation of
+    // fs.lchown, which would always try to call fs.open on a directory
+    // Fall back to fs.chown in those cases.
+    if (!er || er.code !== 'EISDIR')
+      cb(er)
+    else
+      fs.chown(path, uid, gid, cb)
+  }
+  : (_, __, ___, cb) => cb
+
+/* istanbul ignore next */
+const handleEISDirSync =
+  needEISDIRHandled ? (path, uid, gid) => {
+    try {
+      return lchownSync(path, uid, gid)
+    } catch (er) {
+      if (er.code !== 'EISDIR')
+        throw er
+      chownSync(path, uid, gid)
+    }
+  }
+  : (path, uid, gid) => lchownSync(path, uid, gid)
+
+// fs.readdir could only accept an options object as of node v6
+const nodeVersion = process.version
+let readdir = (path, options, cb) => fs.readdir(path, options, cb)
+let readdirSync = (path, options) => fs.readdirSync(path, options)
+/* istanbul ignore next */
+if (/^v4\./.test(nodeVersion))
+  readdir = (path, options, cb) => fs.readdir(path, cb)
+
+const chown = (cpath, uid, gid, cb) => {
+  fs[LCHOWN](cpath, uid, gid, handleEISDIR(cpath, uid, gid, er => {
+    // Skip ENOENT error
+    cb(er && er.code !== 'ENOENT' ? er : null)
+  }))
+}
+
+const chownrKid = (p, child, uid, gid, cb) => {
+  if (typeof child === 'string')
+    return fs.lstat(path.resolve(p, child), (er, stats) => {
+      // Skip ENOENT error
+      if (er)
+        return cb(er.code !== 'ENOENT' ? er : null)
+      stats.name = child
+      chownrKid(p, stats, uid, gid, cb)
+    })
+
+  if (child.isDirectory()) {
+    chownr(path.resolve(p, child.name), uid, gid, er => {
+      if (er)
+        return cb(er)
+      const cpath = path.resolve(p, child.name)
+      chown(cpath, uid, gid, cb)
+    })
+  } else {
+    const cpath = path.resolve(p, child.name)
+    chown(cpath, uid, gid, cb)
+  }
+}
+
+
+const chownr = (p, uid, gid, cb) => {
+  readdir(p, { withFileTypes: true }, (er, children) => {
+    // any error other than ENOTDIR or ENOTSUP means it's not readable,
+    // or doesn't exist.  give up.
+    if (er) {
+      if (er.code === 'ENOENT')
+        return cb()
+      else if (er.code !== 'ENOTDIR' && er.code !== 'ENOTSUP')
+        return cb(er)
+    }
+    if (er || !children.length)
+      return chown(p, uid, gid, cb)
+
+    let len = children.length
+    let errState = null
+    const then = er => {
+      if (errState)
+        return
+      if (er)
+        return cb(errState = er)
+      if (-- len === 0)
+        return chown(p, uid, gid, cb)
+    }
+
+    children.forEach(child => chownrKid(p, child, uid, gid, then))
+  })
+}
+
+const chownrKidSync = (p, child, uid, gid) => {
+  if (typeof child === 'string') {
+    try {
+      const stats = fs.lstatSync(path.resolve(p, child))
+      stats.name = child
+      child = stats
+    } catch (er) {
+      if (er.code === 'ENOENT')
+        return
+      else
+        throw er
+    }
+  }
+
+  if (child.isDirectory())
+    chownrSync(path.resolve(p, child.name), uid, gid)
+
+  handleEISDirSync(path.resolve(p, child.name), uid, gid)
+}
+
+const chownrSync = (p, uid, gid) => {
+  let children
+  try {
+    children = readdirSync(p, { withFileTypes: true })
+  } catch (er) {
+    if (er.code === 'ENOENT')
+      return
+    else if (er.code === 'ENOTDIR' || er.code === 'ENOTSUP')
+      return handleEISDirSync(p, uid, gid)
+    else
+      throw er
+  }
+
+  if (children && children.length)
+    children.forEach(child => chownrKidSync(p, child, uid, gid))
+
+  return handleEISDirSync(p, uid, gid)
+}
+
+module.exports = chownr
+chownr.sync = chownrSync
diff --git a/server/node_modules/cacache/node_modules/chownr/package.json b/server/node_modules/cacache/node_modules/chownr/package.json
new file mode 100644
index 0000000..5b0214c
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/chownr/package.json
@@ -0,0 +1,32 @@
+{
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "name": "chownr",
+  "description": "like `chown -R`",
+  "version": "2.0.0",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/isaacs/chownr.git"
+  },
+  "main": "chownr.js",
+  "files": [
+    "chownr.js"
+  ],
+  "devDependencies": {
+    "mkdirp": "0.3",
+    "rimraf": "^2.7.1",
+    "tap": "^14.10.6"
+  },
+  "tap": {
+    "check-coverage": true
+  },
+  "scripts": {
+    "test": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags"
+  },
+  "license": "ISC",
+  "engines": {
+    "node": ">=10"
+  }
+}
diff --git a/server/node_modules/cacache/node_modules/mkdirp/CHANGELOG.md b/server/node_modules/cacache/node_modules/mkdirp/CHANGELOG.md
new file mode 100644
index 0000000..8145838
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/CHANGELOG.md
@@ -0,0 +1,15 @@
+# Changers Lorgs!
+
+## 1.0
+
+Full rewrite.  Essentially a brand new module.
+
+- Return a promise instead of taking a callback.
+- Use native `fs.mkdir(path, { recursive: true })` when available.
+- Drop support for outdated Node.js versions.  (Technically still works on
+  Node.js v8, but only 10 and above are officially supported.)
+
+## 0.x
+
+Original and most widely used recursive directory creation implementation
+in JavaScript, dating back to 2010.
diff --git a/server/node_modules/cacache/node_modules/mkdirp/LICENSE b/server/node_modules/cacache/node_modules/mkdirp/LICENSE
new file mode 100644
index 0000000..13fcd15
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/LICENSE
@@ -0,0 +1,21 @@
+Copyright James Halliday (mail@substack.net) and Isaac Z. Schlueter (i@izs.me)
+
+This project is free software released under the MIT license:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/cacache/node_modules/mkdirp/bin/cmd.js b/server/node_modules/cacache/node_modules/mkdirp/bin/cmd.js
new file mode 100755
index 0000000..6e0aa8d
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/bin/cmd.js
@@ -0,0 +1,68 @@
+#!/usr/bin/env node
+
+const usage = () => `
+usage: mkdirp [DIR1,DIR2..] {OPTIONS}
+
+  Create each supplied directory including any necessary parent directories
+  that don't yet exist.
+
+  If the directory already exists, do nothing.
+
+OPTIONS are:
+
+  -m<mode>       If a directory needs to be created, set the mode as an octal
+  --mode=<mode>  permission string.
+
+  -v --version   Print the mkdirp version number
+
+  -h --help      Print this helpful banner
+
+  -p --print     Print the first directories created for each path provided
+
+  --manual       Use manual implementation, even if native is available
+`
+
+const dirs = []
+const opts = {}
+let print = false
+let dashdash = false
+let manual = false
+for (const arg of process.argv.slice(2)) {
+  if (dashdash)
+    dirs.push(arg)
+  else if (arg === '--')
+    dashdash = true
+  else if (arg === '--manual')
+    manual = true
+  else if (/^-h/.test(arg) || /^--help/.test(arg)) {
+    console.log(usage())
+    process.exit(0)
+  } else if (arg === '-v' || arg === '--version') {
+    console.log(require('../package.json').version)
+    process.exit(0)
+  } else if (arg === '-p' || arg === '--print') {
+    print = true
+  } else if (/^-m/.test(arg) || /^--mode=/.test(arg)) {
+    const mode = parseInt(arg.replace(/^(-m|--mode=)/, ''), 8)
+    if (isNaN(mode)) {
+      console.error(`invalid mode argument: ${arg}\nMust be an octal number.`)
+      process.exit(1)
+    }
+    opts.mode = mode
+  } else
+    dirs.push(arg)
+}
+
+const mkdirp = require('../')
+const impl = manual ? mkdirp.manual : mkdirp
+if (dirs.length === 0)
+  console.error(usage())
+
+Promise.all(dirs.map(dir => impl(dir, opts)))
+  .then(made => print ? made.forEach(m => m && console.log(m)) : null)
+  .catch(er => {
+    console.error(er.message)
+    if (er.code)
+      console.error('  code: ' + er.code)
+    process.exit(1)
+  })
diff --git a/server/node_modules/cacache/node_modules/mkdirp/index.js b/server/node_modules/cacache/node_modules/mkdirp/index.js
new file mode 100644
index 0000000..ad7a16c
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/index.js
@@ -0,0 +1,31 @@
+const optsArg = require('./lib/opts-arg.js')
+const pathArg = require('./lib/path-arg.js')
+
+const {mkdirpNative, mkdirpNativeSync} = require('./lib/mkdirp-native.js')
+const {mkdirpManual, mkdirpManualSync} = require('./lib/mkdirp-manual.js')
+const {useNative, useNativeSync} = require('./lib/use-native.js')
+
+
+const mkdirp = (path, opts) => {
+  path = pathArg(path)
+  opts = optsArg(opts)
+  return useNative(opts)
+    ? mkdirpNative(path, opts)
+    : mkdirpManual(path, opts)
+}
+
+const mkdirpSync = (path, opts) => {
+  path = pathArg(path)
+  opts = optsArg(opts)
+  return useNativeSync(opts)
+    ? mkdirpNativeSync(path, opts)
+    : mkdirpManualSync(path, opts)
+}
+
+mkdirp.sync = mkdirpSync
+mkdirp.native = (path, opts) => mkdirpNative(pathArg(path), optsArg(opts))
+mkdirp.manual = (path, opts) => mkdirpManual(pathArg(path), optsArg(opts))
+mkdirp.nativeSync = (path, opts) => mkdirpNativeSync(pathArg(path), optsArg(opts))
+mkdirp.manualSync = (path, opts) => mkdirpManualSync(pathArg(path), optsArg(opts))
+
+module.exports = mkdirp
diff --git a/server/node_modules/cacache/node_modules/mkdirp/lib/find-made.js b/server/node_modules/cacache/node_modules/mkdirp/lib/find-made.js
new file mode 100644
index 0000000..022e492
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/lib/find-made.js
@@ -0,0 +1,29 @@
+const {dirname} = require('path')
+
+const findMade = (opts, parent, path = undefined) => {
+  // we never want the 'made' return value to be a root directory
+  if (path === parent)
+    return Promise.resolve()
+
+  return opts.statAsync(parent).then(
+    st => st.isDirectory() ? path : undefined, // will fail later
+    er => er.code === 'ENOENT'
+      ? findMade(opts, dirname(parent), parent)
+      : undefined
+  )
+}
+
+const findMadeSync = (opts, parent, path = undefined) => {
+  if (path === parent)
+    return undefined
+
+  try {
+    return opts.statSync(parent).isDirectory() ? path : undefined
+  } catch (er) {
+    return er.code === 'ENOENT'
+      ? findMadeSync(opts, dirname(parent), parent)
+      : undefined
+  }
+}
+
+module.exports = {findMade, findMadeSync}
diff --git a/server/node_modules/cacache/node_modules/mkdirp/lib/mkdirp-manual.js b/server/node_modules/cacache/node_modules/mkdirp/lib/mkdirp-manual.js
new file mode 100644
index 0000000..2eb18cd
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/lib/mkdirp-manual.js
@@ -0,0 +1,64 @@
+const {dirname} = require('path')
+
+const mkdirpManual = (path, opts, made) => {
+  opts.recursive = false
+  const parent = dirname(path)
+  if (parent === path) {
+    return opts.mkdirAsync(path, opts).catch(er => {
+      // swallowed by recursive implementation on posix systems
+      // any other error is a failure
+      if (er.code !== 'EISDIR')
+        throw er
+    })
+  }
+
+  return opts.mkdirAsync(path, opts).then(() => made || path, er => {
+    if (er.code === 'ENOENT')
+      return mkdirpManual(parent, opts)
+        .then(made => mkdirpManual(path, opts, made))
+    if (er.code !== 'EEXIST' && er.code !== 'EROFS')
+      throw er
+    return opts.statAsync(path).then(st => {
+      if (st.isDirectory())
+        return made
+      else
+        throw er
+    }, () => { throw er })
+  })
+}
+
+const mkdirpManualSync = (path, opts, made) => {
+  const parent = dirname(path)
+  opts.recursive = false
+
+  if (parent === path) {
+    try {
+      return opts.mkdirSync(path, opts)
+    } catch (er) {
+      // swallowed by recursive implementation on posix systems
+      // any other error is a failure
+      if (er.code !== 'EISDIR')
+        throw er
+      else
+        return
+    }
+  }
+
+  try {
+    opts.mkdirSync(path, opts)
+    return made || path
+  } catch (er) {
+    if (er.code === 'ENOENT')
+      return mkdirpManualSync(path, opts, mkdirpManualSync(parent, opts, made))
+    if (er.code !== 'EEXIST' && er.code !== 'EROFS')
+      throw er
+    try {
+      if (!opts.statSync(path).isDirectory())
+        throw er
+    } catch (_) {
+      throw er
+    }
+  }
+}
+
+module.exports = {mkdirpManual, mkdirpManualSync}
diff --git a/server/node_modules/cacache/node_modules/mkdirp/lib/mkdirp-native.js b/server/node_modules/cacache/node_modules/mkdirp/lib/mkdirp-native.js
new file mode 100644
index 0000000..c7a6b69
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/lib/mkdirp-native.js
@@ -0,0 +1,39 @@
+const {dirname} = require('path')
+const {findMade, findMadeSync} = require('./find-made.js')
+const {mkdirpManual, mkdirpManualSync} = require('./mkdirp-manual.js')
+
+const mkdirpNative = (path, opts) => {
+  opts.recursive = true
+  const parent = dirname(path)
+  if (parent === path)
+    return opts.mkdirAsync(path, opts)
+
+  return findMade(opts, path).then(made =>
+    opts.mkdirAsync(path, opts).then(() => made)
+    .catch(er => {
+      if (er.code === 'ENOENT')
+        return mkdirpManual(path, opts)
+      else
+        throw er
+    }))
+}
+
+const mkdirpNativeSync = (path, opts) => {
+  opts.recursive = true
+  const parent = dirname(path)
+  if (parent === path)
+    return opts.mkdirSync(path, opts)
+
+  const made = findMadeSync(opts, path)
+  try {
+    opts.mkdirSync(path, opts)
+    return made
+  } catch (er) {
+    if (er.code === 'ENOENT')
+      return mkdirpManualSync(path, opts)
+    else
+      throw er
+  }
+}
+
+module.exports = {mkdirpNative, mkdirpNativeSync}
diff --git a/server/node_modules/cacache/node_modules/mkdirp/lib/opts-arg.js b/server/node_modules/cacache/node_modules/mkdirp/lib/opts-arg.js
new file mode 100644
index 0000000..2fa4833
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/lib/opts-arg.js
@@ -0,0 +1,23 @@
+const { promisify } = require('util')
+const fs = require('fs')
+const optsArg = opts => {
+  if (!opts)
+    opts = { mode: 0o777, fs }
+  else if (typeof opts === 'object')
+    opts = { mode: 0o777, fs, ...opts }
+  else if (typeof opts === 'number')
+    opts = { mode: opts, fs }
+  else if (typeof opts === 'string')
+    opts = { mode: parseInt(opts, 8), fs }
+  else
+    throw new TypeError('invalid options argument')
+
+  opts.mkdir = opts.mkdir || opts.fs.mkdir || fs.mkdir
+  opts.mkdirAsync = promisify(opts.mkdir)
+  opts.stat = opts.stat || opts.fs.stat || fs.stat
+  opts.statAsync = promisify(opts.stat)
+  opts.statSync = opts.statSync || opts.fs.statSync || fs.statSync
+  opts.mkdirSync = opts.mkdirSync || opts.fs.mkdirSync || fs.mkdirSync
+  return opts
+}
+module.exports = optsArg
diff --git a/server/node_modules/cacache/node_modules/mkdirp/lib/path-arg.js b/server/node_modules/cacache/node_modules/mkdirp/lib/path-arg.js
new file mode 100644
index 0000000..cc07de5
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/lib/path-arg.js
@@ -0,0 +1,29 @@
+const platform = process.env.__TESTING_MKDIRP_PLATFORM__ || process.platform
+const { resolve, parse } = require('path')
+const pathArg = path => {
+  if (/\0/.test(path)) {
+    // simulate same failure that node raises
+    throw Object.assign(
+      new TypeError('path must be a string without null bytes'),
+      {
+        path,
+        code: 'ERR_INVALID_ARG_VALUE',
+      }
+    )
+  }
+
+  path = resolve(path)
+  if (platform === 'win32') {
+    const badWinChars = /[*|"<>?:]/
+    const {root} = parse(path)
+    if (badWinChars.test(path.substr(root.length))) {
+      throw Object.assign(new Error('Illegal characters in path.'), {
+        path,
+        code: 'EINVAL',
+      })
+    }
+  }
+
+  return path
+}
+module.exports = pathArg
diff --git a/server/node_modules/cacache/node_modules/mkdirp/lib/use-native.js b/server/node_modules/cacache/node_modules/mkdirp/lib/use-native.js
new file mode 100644
index 0000000..079361d
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/lib/use-native.js
@@ -0,0 +1,10 @@
+const fs = require('fs')
+
+const version = process.env.__TESTING_MKDIRP_NODE_VERSION__ || process.version
+const versArr = version.replace(/^v/, '').split('.')
+const hasNative = +versArr[0] > 10 || +versArr[0] === 10 && +versArr[1] >= 12
+
+const useNative = !hasNative ? () => false : opts => opts.mkdir === fs.mkdir
+const useNativeSync = !hasNative ? () => false : opts => opts.mkdirSync === fs.mkdirSync
+
+module.exports = {useNative, useNativeSync}
diff --git a/server/node_modules/cacache/node_modules/mkdirp/package.json b/server/node_modules/cacache/node_modules/mkdirp/package.json
new file mode 100644
index 0000000..2913ed0
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "mkdirp",
+  "description": "Recursively mkdir, like `mkdir -p`",
+  "version": "1.0.4",
+  "main": "index.js",
+  "keywords": [
+    "mkdir",
+    "directory",
+    "make dir",
+    "make",
+    "dir",
+    "recursive",
+    "native"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/isaacs/node-mkdirp.git"
+  },
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "tap": {
+    "check-coverage": true,
+    "coverage-map": "map.js"
+  },
+  "devDependencies": {
+    "require-inject": "^1.4.4",
+    "tap": "^14.10.7"
+  },
+  "bin": "bin/cmd.js",
+  "license": "MIT",
+  "engines": {
+    "node": ">=10"
+  },
+  "files": [
+    "bin",
+    "lib",
+    "index.js"
+  ]
+}
diff --git a/server/node_modules/cacache/node_modules/mkdirp/readme.markdown b/server/node_modules/cacache/node_modules/mkdirp/readme.markdown
new file mode 100644
index 0000000..827de59
--- /dev/null
+++ b/server/node_modules/cacache/node_modules/mkdirp/readme.markdown
@@ -0,0 +1,266 @@
+# mkdirp
+
+Like `mkdir -p`, but in Node.js!
+
+Now with a modern API and no\* bugs!
+
+<small>\* may contain some bugs</small>
+
+# example
+
+## pow.js
+
+```js
+const mkdirp = require('mkdirp')
+
+// return value is a Promise resolving to the first directory created
+mkdirp('/tmp/foo/bar/baz').then(made =>
+  console.log(`made directories, starting with ${made}`))
+```
+
+Output (where `/tmp/foo` already exists)
+
+```
+made directories, starting with /tmp/foo/bar
+```
+
+Or, if you don't have time to wait around for promises:
+
+```js
+const mkdirp = require('mkdirp')
+
+// return value is the first directory created
+const made = mkdirp.sync('/tmp/foo/bar/baz')
+console.log(`made directories, starting with ${made}`)
+```
+
+And now /tmp/foo/bar/baz exists, huzzah!
+
+# methods
+
+```js
+const mkdirp = require('mkdirp')
+```
+
+## mkdirp(dir, [opts]) -> Promise<String | undefined>
+
+Create a new directory and any necessary subdirectories at `dir` with octal
+permission string `opts.mode`. If `opts` is a string or number, it will be
+treated as the `opts.mode`.
+
+If `opts.mode` isn't specified, it defaults to `0o777 &
+(~process.umask())`.
+
+Promise resolves to first directory `made` that had to be created, or
+`undefined` if everything already exists.  Promise rejects if any errors
+are encountered.  Note that, in the case of promise rejection, some
+directories _may_ have been created, as recursive directory creation is not
+an atomic operation.
+
+You can optionally pass in an alternate `fs` implementation by passing in
+`opts.fs`. Your implementation should have `opts.fs.mkdir(path, opts, cb)`
+and `opts.fs.stat(path, cb)`.
+
+You can also override just one or the other of `mkdir` and `stat` by
+passing in `opts.stat` or `opts.mkdir`, or providing an `fs` option that
+only overrides one of these.
+
+## mkdirp.sync(dir, opts) -> String|null
+
+Synchronously create a new directory and any necessary subdirectories at
+`dir` with octal permission string `opts.mode`. If `opts` is a string or
+number, it will be treated as the `opts.mode`.
+
+If `opts.mode` isn't specified, it defaults to `0o777 &
+(~process.umask())`.
+
+Returns the first directory that had to be created, or undefined if
+everything already exists.
+
+You can optionally pass in an alternate `fs` implementation by passing in
+`opts.fs`. Your implementation should have `opts.fs.mkdirSync(path, mode)`
+and `opts.fs.statSync(path)`.
+
+You can also override just one or the other of `mkdirSync` and `statSync`
+by passing in `opts.statSync` or `opts.mkdirSync`, or providing an `fs`
+option that only overrides one of these.
+
+## mkdirp.manual, mkdirp.manualSync
+
+Use the manual implementation (not the native one).  This is the default
+when the native implementation is not available or the stat/mkdir
+implementation is overridden.
+
+## mkdirp.native, mkdirp.nativeSync
+
+Use the native implementation (not the manual one).  This is the default
+when the native implementation is available and stat/mkdir are not
+overridden.
+
+# implementation
+
+On Node.js v10.12.0 and above, use the native `fs.mkdir(p,
+{recursive:true})` option, unless `fs.mkdir`/`fs.mkdirSync` has been
+overridden by an option.
+
+## native implementation
+
+- If the path is a root directory, then pass it to the underlying
+  implementation and return the result/error.  (In this case, it'll either
+  succeed or fail, but we aren't actually creating any dirs.)
+- Walk up the path statting each directory, to find the first path that
+  will be created, `made`.
+- Call `fs.mkdir(path, { recursive: true })` (or `fs.mkdirSync`)
+- If error, raise it to the caller.
+- Return `made`.
+
+## manual implementation
+
+- Call underlying `fs.mkdir` implementation, with `recursive: false`
+- If error:
+  - If path is a root directory, raise to the caller and do not handle it
+  - If ENOENT, mkdirp parent dir, store result as `made`
+  - stat(path)
+    - If error, raise original `mkdir` error
+    - If directory, return `made`
+    - Else, raise original `mkdir` error
+- else
+  - return `undefined` if a root dir, or `made` if set, or `path`
+
+## windows vs unix caveat
+
+On Windows file systems, attempts to create a root directory (ie, a drive
+letter or root UNC path) will fail.  If the root directory exists, then it
+will fail with `EPERM`.  If the root directory does not exist, then it will
+fail with `ENOENT`.
+
+On posix file systems, attempts to create a root directory (in recursive
+mode) will succeed silently, as it is treated like just another directory
+that already exists.  (In non-recursive mode, of course, it fails with
+`EEXIST`.)
+
+In order to preserve this system-specific behavior (and because it's not as
+if we can create the parent of a root directory anyway), attempts to create
+a root directory are passed directly to the `fs` implementation, and any
+errors encountered are not handled.
+
+## native error caveat
+
+The native implementation (as of at least Node.js v13.4.0) does not provide
+appropriate errors in some cases (see
+[nodejs/node#31481](https://github.com/nodejs/node/issues/31481) and
+[nodejs/node#28015](https://github.com/nodejs/node/issues/28015)).
+
+In order to work around this issue, the native implementation will fall
+back to the manual implementation if an `ENOENT` error is encountered.
+
+# choosing a recursive mkdir implementation
+
+There are a few to choose from!  Use the one that suits your needs best :D
+
+## use `fs.mkdir(path, {recursive: true}, cb)` if:
+
+- You wish to optimize performance even at the expense of other factors.
+- You don't need to know the first dir created.
+- You are ok with getting `ENOENT` as the error when some other problem is
+  the actual cause.
+- You can limit your platforms to Node.js v10.12 and above.
+- You're ok with using callbacks instead of promises.
+- You don't need/want a CLI.
+- You don't need to override the `fs` methods in use.
+
+## use this module (mkdirp 1.x) if:
+
+- You need to know the first directory that was created.
+- You wish to use the native implementation if available, but fall back
+  when it's not.
+- You prefer promise-returning APIs to callback-taking APIs.
+- You want more useful error messages than the native recursive mkdir
+  provides (at least as of Node.js v13.4), and are ok with re-trying on
+  `ENOENT` to achieve this.
+- You need (or at least, are ok with) a CLI.
+- You need to override the `fs` methods in use.
+
+## use [`make-dir`](http://npm.im/make-dir) if:
+
+- You do not need to know the first dir created (and wish to save a few
+  `stat` calls when using the native implementation for this reason).
+- You wish to use the native implementation if available, but fall back
+  when it's not.
+- You prefer promise-returning APIs to callback-taking APIs.
+- You are ok with occasionally getting `ENOENT` errors for failures that
+  are actually related to something other than a missing file system entry.
+- You don't need/want a CLI.
+- You need to override the `fs` methods in use.
+
+## use mkdirp 0.x if:
+
+- You need to know the first directory that was created.
+- You need (or at least, are ok with) a CLI.
+- You need to override the `fs` methods in use.
+- You're ok with using callbacks instead of promises.
+- You are not running on Windows, where the root-level ENOENT errors can
+  lead to infinite regress.
+- You think vinyl just sounds warmer and richer for some weird reason.
+- You are supporting truly ancient Node.js versions, before even the advent
+  of a `Promise` language primitive.  (Please don't.  You deserve better.)
+
+# cli
+
+This package also ships with a `mkdirp` command.
+
+```
+$ mkdirp -h
+
+usage: mkdirp [DIR1,DIR2..] {OPTIONS}
+
+  Create each supplied directory including any necessary parent directories
+  that don't yet exist.
+
+  If the directory already exists, do nothing.
+
+OPTIONS are:
+
+  -m<mode>       If a directory needs to be created, set the mode as an octal
+  --mode=<mode>  permission string.
+
+  -v --version   Print the mkdirp version number
+
+  -h --help      Print this helpful banner
+
+  -p --print     Print the first directories created for each path provided
+
+  --manual       Use manual implementation, even if native is available
+```
+
+# install
+
+With [npm](http://npmjs.org) do:
+
+```
+npm install mkdirp
+```
+
+to get the library locally, or
+
+```
+npm install -g mkdirp
+```
+
+to get the command everywhere, or
+
+```
+npx mkdirp ...
+```
+
+to run the command without installing it globally.
+
+# platform support
+
+This module works on node v8, but only v10 and above are officially
+supported, as Node v8 reached its LTS end of life 2020-01-01, which is in
+the past, as of this writing.
+
+# license
+
+MIT
diff --git a/server/node_modules/cacache/package.json b/server/node_modules/cacache/package.json
new file mode 100644
index 0000000..6cb4140
--- /dev/null
+++ b/server/node_modules/cacache/package.json
@@ -0,0 +1,80 @@
+{
+  "name": "cacache",
+  "version": "15.3.0",
+  "cache-version": {
+    "content": "2",
+    "index": "5"
+  },
+  "description": "Fast, fault-tolerant, cross-platform, disk-based, data-agnostic, content-addressable cache.",
+  "main": "index.js",
+  "files": [
+    "*.js",
+    "lib"
+  ],
+  "scripts": {
+    "benchmarks": "node test/benchmarks",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags",
+    "test": "tap",
+    "snap": "tap",
+    "coverage": "tap",
+    "test-docker": "docker run -it --rm --name pacotest -v \"$PWD\":/tmp -w /tmp node:latest npm test",
+    "lint": "npm run npmclilint -- \"*.*js\" \"lib/**/*.*js\" \"test/**/*.*js\"",
+    "npmclilint": "npmcli-lint",
+    "lintfix": "npm run lint -- --fix",
+    "postsnap": "npm run lintfix --"
+  },
+  "repository": "https://github.com/npm/cacache",
+  "keywords": [
+    "cache",
+    "caching",
+    "content-addressable",
+    "sri",
+    "sri hash",
+    "subresource integrity",
+    "cache",
+    "storage",
+    "store",
+    "file store",
+    "filesystem",
+    "disk cache",
+    "disk storage"
+  ],
+  "license": "ISC",
+  "dependencies": {
+    "@npmcli/fs": "^1.0.0",
+    "@npmcli/move-file": "^1.0.1",
+    "chownr": "^2.0.0",
+    "fs-minipass": "^2.0.0",
+    "glob": "^7.1.4",
+    "infer-owner": "^1.0.4",
+    "lru-cache": "^6.0.0",
+    "minipass": "^3.1.1",
+    "minipass-collect": "^1.0.2",
+    "minipass-flush": "^1.0.5",
+    "minipass-pipeline": "^1.2.2",
+    "mkdirp": "^1.0.3",
+    "p-map": "^4.0.0",
+    "promise-inflight": "^1.0.1",
+    "rimraf": "^3.0.2",
+    "ssri": "^8.0.1",
+    "tar": "^6.0.2",
+    "unique-filename": "^1.1.1"
+  },
+  "devDependencies": {
+    "@npmcli/lint": "^1.0.1",
+    "benchmark": "^2.1.4",
+    "chalk": "^4.0.0",
+    "require-inject": "^1.4.4",
+    "tacks": "^1.3.0",
+    "tap": "^15.0.9"
+  },
+  "tap": {
+    "100": true,
+    "test-regex": "test/[^/]*.js"
+  },
+  "engines": {
+    "node": ">= 10"
+  }
+}
diff --git a/server/node_modules/cacache/put.js b/server/node_modules/cacache/put.js
new file mode 100644
index 0000000..84e9562
--- /dev/null
+++ b/server/node_modules/cacache/put.js
@@ -0,0 +1,83 @@
+'use strict'
+
+const index = require('./lib/entry-index')
+const memo = require('./lib/memoization')
+const write = require('./lib/content/write')
+const Flush = require('minipass-flush')
+const { PassThrough } = require('minipass-collect')
+const Pipeline = require('minipass-pipeline')
+
+const putOpts = (opts) => ({
+  algorithms: ['sha512'],
+  ...opts,
+})
+
+module.exports = putData
+
+function putData (cache, key, data, opts = {}) {
+  const { memoize } = opts
+  opts = putOpts(opts)
+  return write(cache, data, opts).then((res) => {
+    return index
+      .insert(cache, key, res.integrity, { ...opts, size: res.size })
+      .then((entry) => {
+        if (memoize)
+          memo.put(cache, entry, data, opts)
+
+        return res.integrity
+      })
+  })
+}
+
+module.exports.stream = putStream
+
+function putStream (cache, key, opts = {}) {
+  const { memoize } = opts
+  opts = putOpts(opts)
+  let integrity
+  let size
+
+  let memoData
+  const pipeline = new Pipeline()
+  // first item in the pipeline is the memoizer, because we need
+  // that to end first and get the collected data.
+  if (memoize) {
+    const memoizer = new PassThrough().on('collect', data => {
+      memoData = data
+    })
+    pipeline.push(memoizer)
+  }
+
+  // contentStream is a write-only, not a passthrough
+  // no data comes out of it.
+  const contentStream = write.stream(cache, opts)
+    .on('integrity', (int) => {
+      integrity = int
+    })
+    .on('size', (s) => {
+      size = s
+    })
+
+  pipeline.push(contentStream)
+
+  // last but not least, we write the index and emit hash and size,
+  // and memoize if we're doing that
+  pipeline.push(new Flush({
+    flush () {
+      return index
+        .insert(cache, key, integrity, { ...opts, size })
+        .then((entry) => {
+          if (memoize && memoData)
+            memo.put(cache, entry, memoData, opts)
+
+          if (integrity)
+            pipeline.emit('integrity', integrity)
+
+          if (size)
+            pipeline.emit('size', size)
+        })
+    },
+  }))
+
+  return pipeline
+}
diff --git a/server/node_modules/cacache/rm.js b/server/node_modules/cacache/rm.js
new file mode 100644
index 0000000..f2ef6b1
--- /dev/null
+++ b/server/node_modules/cacache/rm.js
@@ -0,0 +1,31 @@
+'use strict'
+
+const util = require('util')
+
+const index = require('./lib/entry-index')
+const memo = require('./lib/memoization')
+const path = require('path')
+const rimraf = util.promisify(require('rimraf'))
+const rmContent = require('./lib/content/rm')
+
+module.exports = entry
+module.exports.entry = entry
+
+function entry (cache, key, opts) {
+  memo.clearMemoized()
+  return index.delete(cache, key, opts)
+}
+
+module.exports.content = content
+
+function content (cache, integrity) {
+  memo.clearMemoized()
+  return rmContent(cache, integrity)
+}
+
+module.exports.all = all
+
+function all (cache) {
+  memo.clearMemoized()
+  return rimraf(path.join(cache, '*(content-*|index-*)'))
+}
diff --git a/server/node_modules/cacache/verify.js b/server/node_modules/cacache/verify.js
new file mode 100644
index 0000000..db7763d
--- /dev/null
+++ b/server/node_modules/cacache/verify.js
@@ -0,0 +1,3 @@
+'use strict'
+
+module.exports = require('./lib/verify')
diff --git a/server/node_modules/call-bind-apply-helpers/.eslintrc b/server/node_modules/call-bind-apply-helpers/.eslintrc
new file mode 100644
index 0000000..201e859
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/.eslintrc
@@ -0,0 +1,17 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"func-name-matching": 0,
+		"id-length": 0,
+		"new-cap": [2, {
+			"capIsNewExceptions": [
+				"GetIntrinsic",
+			],
+		}],
+		"no-extra-parens": 0,
+		"no-magic-numbers": 0,
+	},
+}
diff --git a/server/node_modules/call-bind-apply-helpers/.github/FUNDING.yml b/server/node_modules/call-bind-apply-helpers/.github/FUNDING.yml
new file mode 100644
index 0000000..0011e9d
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/call-bind-apply-helpers
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/call-bind-apply-helpers/.nycrc b/server/node_modules/call-bind-apply-helpers/.nycrc
new file mode 100644
index 0000000..bdd626c
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/.nycrc
@@ -0,0 +1,9 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/call-bind-apply-helpers/CHANGELOG.md b/server/node_modules/call-bind-apply-helpers/CHANGELOG.md
new file mode 100644
index 0000000..2484942
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/CHANGELOG.md
@@ -0,0 +1,30 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.0.2](https://github.com/ljharb/call-bind-apply-helpers/compare/v1.0.1...v1.0.2) - 2025-02-12
+
+### Commits
+
+- [types] improve inferred types [`e6f9586`](https://github.com/ljharb/call-bind-apply-helpers/commit/e6f95860a3c72879cb861a858cdfb8138fbedec1)
+- [Dev Deps] update `@arethetypeswrong/cli`, `@ljharb/tsconfig`, `@types/tape`, `es-value-fixtures`, `for-each`, `has-strict-mode`, `object-inspect` [`e43d540`](https://github.com/ljharb/call-bind-apply-helpers/commit/e43d5409f97543bfbb11f345d47d8ce4e066d8c1)
+
+## [v1.0.1](https://github.com/ljharb/call-bind-apply-helpers/compare/v1.0.0...v1.0.1) - 2024-12-08
+
+### Commits
+
+- [types] `reflectApply`: fix types [`4efc396`](https://github.com/ljharb/call-bind-apply-helpers/commit/4efc3965351a4f02cc55e836fa391d3d11ef2ef8)
+- [Fix] `reflectApply`: oops, Reflect is not a function [`83cc739`](https://github.com/ljharb/call-bind-apply-helpers/commit/83cc7395de6b79b7730bdf092f1436f0b1263c75)
+- [Dev Deps] update `@arethetypeswrong/cli` [`80bd5d3`](https://github.com/ljharb/call-bind-apply-helpers/commit/80bd5d3ae58b4f6b6995ce439dd5a1bcb178a940)
+
+## v1.0.0 - 2024-12-05
+
+### Commits
+
+- Initial implementation, tests, readme [`7879629`](https://github.com/ljharb/call-bind-apply-helpers/commit/78796290f9b7430c9934d6f33d94ae9bc89fce04)
+- Initial commit [`3f1dc16`](https://github.com/ljharb/call-bind-apply-helpers/commit/3f1dc164afc43285631b114a5f9dd9137b2b952f)
+- npm init [`081df04`](https://github.com/ljharb/call-bind-apply-helpers/commit/081df048c312fcee400922026f6e97281200a603)
+- Only apps should have lockfiles [`5b9ca0f`](https://github.com/ljharb/call-bind-apply-helpers/commit/5b9ca0fe8101ebfaf309c549caac4e0a017ed930)
diff --git a/server/node_modules/call-bind-apply-helpers/LICENSE b/server/node_modules/call-bind-apply-helpers/LICENSE
new file mode 100644
index 0000000..f82f389
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/call-bind-apply-helpers/README.md b/server/node_modules/call-bind-apply-helpers/README.md
new file mode 100644
index 0000000..8fc0dae
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/README.md
@@ -0,0 +1,62 @@
+# call-bind-apply-helpers <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![dependency status][deps-svg]][deps-url]
+[![dev dependency status][dev-deps-svg]][dev-deps-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+Helper functions around Function call/apply/bind, for use in `call-bind`.
+
+The only packages that should likely ever use this package directly are `call-bind` and `get-intrinsic`.
+Please use `call-bind` unless you have a very good reason not to.
+
+## Getting started
+
+```sh
+npm install --save call-bind-apply-helpers
+```
+
+## Usage/Examples
+
+```js
+const assert = require('assert');
+const callBindBasic = require('call-bind-apply-helpers');
+
+function f(a, b) {
+	assert.equal(this, 1);
+	assert.equal(a, 2);
+	assert.equal(b, 3);
+	assert.equal(arguments.length, 2);
+}
+
+const fBound = callBindBasic([f, 1]);
+
+delete Function.prototype.call;
+delete Function.prototype.bind;
+
+fBound(2, 3);
+```
+
+## Tests
+
+Clone the repo, `npm install`, and run `npm test`
+
+[package-url]: https://npmjs.org/package/call-bind-apply-helpers
+[npm-version-svg]: https://versionbadg.es/ljharb/call-bind-apply-helpers.svg
+[deps-svg]: https://david-dm.org/ljharb/call-bind-apply-helpers.svg
+[deps-url]: https://david-dm.org/ljharb/call-bind-apply-helpers
+[dev-deps-svg]: https://david-dm.org/ljharb/call-bind-apply-helpers/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/call-bind-apply-helpers#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/call-bind-apply-helpers.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/call-bind-apply-helpers.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/call-bind-apply-helpers.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=call-bind-apply-helpers
+[codecov-image]: https://codecov.io/gh/ljharb/call-bind-apply-helpers/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/call-bind-apply-helpers/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/call-bind-apply-helpers
+[actions-url]: https://github.com/ljharb/call-bind-apply-helpers/actions
diff --git a/server/node_modules/call-bind-apply-helpers/actualApply.d.ts b/server/node_modules/call-bind-apply-helpers/actualApply.d.ts
new file mode 100644
index 0000000..b87286a
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/actualApply.d.ts
@@ -0,0 +1 @@
+export = Reflect.apply;
\ No newline at end of file
diff --git a/server/node_modules/call-bind-apply-helpers/actualApply.js b/server/node_modules/call-bind-apply-helpers/actualApply.js
new file mode 100644
index 0000000..ffa5135
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/actualApply.js
@@ -0,0 +1,10 @@
+'use strict';
+
+var bind = require('function-bind');
+
+var $apply = require('./functionApply');
+var $call = require('./functionCall');
+var $reflectApply = require('./reflectApply');
+
+/** @type {import('./actualApply')} */
+module.exports = $reflectApply || bind.call($call, $apply);
diff --git a/server/node_modules/call-bind-apply-helpers/applyBind.d.ts b/server/node_modules/call-bind-apply-helpers/applyBind.d.ts
new file mode 100644
index 0000000..d176c1a
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/applyBind.d.ts
@@ -0,0 +1,19 @@
+import actualApply from './actualApply';
+
+type TupleSplitHead<T extends any[], N extends number> = T['length'] extends N
+  ? T
+  : T extends [...infer R, any]
+  ? TupleSplitHead<R, N>
+  : never
+
+type TupleSplitTail<T, N extends number, O extends any[] = []> = O['length'] extends N
+  ? T
+  : T extends [infer F, ...infer R]
+  ? TupleSplitTail<[...R], N, [...O, F]>
+  : never
+
+type TupleSplit<T extends any[], N extends number> = [TupleSplitHead<T, N>, TupleSplitTail<T, N>]
+
+declare function applyBind(...args: TupleSplit<Parameters<typeof actualApply>, 2>[1]): ReturnType<typeof actualApply>;
+
+export = applyBind;
\ No newline at end of file
diff --git a/server/node_modules/call-bind-apply-helpers/applyBind.js b/server/node_modules/call-bind-apply-helpers/applyBind.js
new file mode 100644
index 0000000..d2b7723
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/applyBind.js
@@ -0,0 +1,10 @@
+'use strict';
+
+var bind = require('function-bind');
+var $apply = require('./functionApply');
+var actualApply = require('./actualApply');
+
+/** @type {import('./applyBind')} */
+module.exports = function applyBind() {
+	return actualApply(bind, $apply, arguments);
+};
diff --git a/server/node_modules/call-bind-apply-helpers/functionApply.d.ts b/server/node_modules/call-bind-apply-helpers/functionApply.d.ts
new file mode 100644
index 0000000..1f6e11b
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/functionApply.d.ts
@@ -0,0 +1 @@
+export = Function.prototype.apply;
\ No newline at end of file
diff --git a/server/node_modules/call-bind-apply-helpers/functionApply.js b/server/node_modules/call-bind-apply-helpers/functionApply.js
new file mode 100644
index 0000000..c71df9c
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/functionApply.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./functionApply')} */
+module.exports = Function.prototype.apply;
diff --git a/server/node_modules/call-bind-apply-helpers/functionCall.d.ts b/server/node_modules/call-bind-apply-helpers/functionCall.d.ts
new file mode 100644
index 0000000..15e93df
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/functionCall.d.ts
@@ -0,0 +1 @@
+export = Function.prototype.call;
\ No newline at end of file
diff --git a/server/node_modules/call-bind-apply-helpers/functionCall.js b/server/node_modules/call-bind-apply-helpers/functionCall.js
new file mode 100644
index 0000000..7a8d873
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/functionCall.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./functionCall')} */
+module.exports = Function.prototype.call;
diff --git a/server/node_modules/call-bind-apply-helpers/index.d.ts b/server/node_modules/call-bind-apply-helpers/index.d.ts
new file mode 100644
index 0000000..541516b
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/index.d.ts
@@ -0,0 +1,64 @@
+type RemoveFromTuple<
+  Tuple extends readonly unknown[],
+  RemoveCount extends number,
+  Index extends 1[] = []
+> = Index["length"] extends RemoveCount
+  ? Tuple
+  : Tuple extends [infer First, ...infer Rest]
+  ? RemoveFromTuple<Rest, RemoveCount, [...Index, 1]>
+  : Tuple;
+
+type ConcatTuples<
+  Prefix extends readonly unknown[],
+  Suffix extends readonly unknown[]
+> = [...Prefix, ...Suffix];
+
+type ExtractFunctionParams<T> = T extends (this: infer TThis, ...args: infer P extends readonly unknown[]) => infer R
+  ? { thisArg: TThis; params: P; returnType: R }
+  : never;
+
+type BindFunction<
+  T extends (this: any, ...args: any[]) => any,
+  TThis,
+  TBoundArgs extends readonly unknown[],
+  ReceiverBound extends boolean
+> = ExtractFunctionParams<T> extends {
+  thisArg: infer OrigThis;
+  params: infer P extends readonly unknown[];
+  returnType: infer R;
+}
+  ? ReceiverBound extends true
+    ? (...args: RemoveFromTuple<P, Extract<TBoundArgs["length"], number>>) => R extends [OrigThis, ...infer Rest]
+      ? [TThis, ...Rest] // Replace `this` with `thisArg`
+      : R
+    : <U, RemainingArgs extends RemoveFromTuple<P, Extract<TBoundArgs["length"], number>>>(
+        thisArg: U,
+        ...args: RemainingArgs
+      ) => R extends [OrigThis, ...infer Rest]
+      ? [U, ...ConcatTuples<TBoundArgs, Rest>] // Preserve bound args in return type
+      : R
+  : never;
+
+declare function callBind<
+  const T extends (this: any, ...args: any[]) => any,
+  Extracted extends ExtractFunctionParams<T>,
+  const TBoundArgs extends Partial<Extracted["params"]> & readonly unknown[],
+  const TThis extends Extracted["thisArg"]
+>(
+  args: [fn: T, thisArg: TThis, ...boundArgs: TBoundArgs]
+): BindFunction<T, TThis, TBoundArgs, true>;
+
+declare function callBind<
+  const T extends (this: any, ...args: any[]) => any,
+  Extracted extends ExtractFunctionParams<T>,
+  const TBoundArgs extends Partial<Extracted["params"]> & readonly unknown[]
+>(
+  args: [fn: T, ...boundArgs: TBoundArgs]
+): BindFunction<T, Extracted["thisArg"], TBoundArgs, false>;
+
+declare function callBind<const TArgs extends readonly unknown[]>(
+  args: [fn: Exclude<TArgs[0], Function>, ...rest: TArgs]
+): never;
+
+// export as namespace callBind;
+export = callBind;
diff --git a/server/node_modules/call-bind-apply-helpers/index.js b/server/node_modules/call-bind-apply-helpers/index.js
new file mode 100644
index 0000000..2f6dab4
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/index.js
@@ -0,0 +1,15 @@
+'use strict';
+
+var bind = require('function-bind');
+var $TypeError = require('es-errors/type');
+
+var $call = require('./functionCall');
+var $actualApply = require('./actualApply');
+
+/** @type {(args: [Function, thisArg?: unknown, ...args: unknown[]]) => Function} TODO FIXME, find a way to use import('.') */
+module.exports = function callBindBasic(args) {
+	if (args.length < 1 || typeof args[0] !== 'function') {
+		throw new $TypeError('a function is required');
+	}
+	return $actualApply(bind, $call, args);
+};
diff --git a/server/node_modules/call-bind-apply-helpers/package.json b/server/node_modules/call-bind-apply-helpers/package.json
new file mode 100644
index 0000000..923b8be
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/package.json
@@ -0,0 +1,85 @@
+{
+	"name": "call-bind-apply-helpers",
+	"version": "1.0.2",
+	"description": "Helper functions around Function call/apply/bind, for use in `call-bind`",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./actualApply": "./actualApply.js",
+		"./applyBind": "./applyBind.js",
+		"./functionApply": "./functionApply.js",
+		"./functionCall": "./functionCall.js",
+		"./reflectApply": "./reflectApply.js",
+		"./package.json": "./package.json"
+	},
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=auto",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prepublishOnly": "safe-publish-latest",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=.js,.mjs .",
+		"postlint": "tsc -p . && attw -P",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>=10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/call-bind-apply-helpers.git"
+	},
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/call-bind-apply-helpers/issues"
+	},
+	"homepage": "https://github.com/ljharb/call-bind-apply-helpers#readme",
+	"dependencies": {
+		"es-errors": "^1.3.0",
+		"function-bind": "^1.1.2"
+	},
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.3",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.3",
+		"@types/for-each": "^0.3.3",
+		"@types/function-bind": "^1.1.10",
+		"@types/object-inspect": "^1.13.0",
+		"@types/tape": "^5.8.1",
+		"auto-changelog": "^2.5.0",
+		"encoding": "^0.1.13",
+		"es-value-fixtures": "^1.7.1",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"for-each": "^0.3.5",
+		"has-strict-mode": "^1.1.0",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"object-inspect": "^1.13.4",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"testling": {
+		"files": "test/index.js"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/call-bind-apply-helpers/reflectApply.d.ts b/server/node_modules/call-bind-apply-helpers/reflectApply.d.ts
new file mode 100644
index 0000000..6b2ae76
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/reflectApply.d.ts
@@ -0,0 +1,3 @@
+declare const reflectApply: false | typeof Reflect.apply;
+
+export = reflectApply;
diff --git a/server/node_modules/call-bind-apply-helpers/reflectApply.js b/server/node_modules/call-bind-apply-helpers/reflectApply.js
new file mode 100644
index 0000000..3d03caa
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/reflectApply.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./reflectApply')} */
+module.exports = typeof Reflect !== 'undefined' && Reflect && Reflect.apply;
diff --git a/server/node_modules/call-bind-apply-helpers/test/index.js b/server/node_modules/call-bind-apply-helpers/test/index.js
new file mode 100644
index 0000000..1cdc89e
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/test/index.js
@@ -0,0 +1,63 @@
+'use strict';
+
+var callBind = require('../');
+var hasStrictMode = require('has-strict-mode')();
+var forEach = require('for-each');
+var inspect = require('object-inspect');
+var v = require('es-value-fixtures');
+
+var test = require('tape');
+
+test('callBindBasic', function (t) {
+	forEach(v.nonFunctions, function (nonFunction) {
+		t['throws'](
+			// @ts-expect-error
+			function () { callBind([nonFunction]); },
+			TypeError,
+			inspect(nonFunction) + ' is not a function'
+		);
+	});
+
+	var sentinel = { sentinel: true };
+	/** @type {<T, A extends number, B extends number>(this: T, a: A, b: B) => [T | undefined, A, B]} */
+	var func = function (a, b) {
+		// eslint-disable-next-line no-invalid-this
+		return [!hasStrictMode && this === global ? undefined : this, a, b];
+	};
+	t.equal(func.length, 2, 'original function length is 2');
+
+	/** type {(thisArg: unknown, a: number, b: number) => [unknown, number, number]} */
+	var bound = callBind([func]);
+	/** type {((a: number, b: number) => [typeof sentinel, typeof a, typeof b])} */
+	var boundR = callBind([func, sentinel]);
+	/** type {((b: number) => [typeof sentinel, number, typeof b])} */
+	var boundArg = callBind([func, sentinel, /** @type {const} */ (1)]);
+
+	// @ts-expect-error
+	t.deepEqual(bound(), [undefined, undefined, undefined], 'bound func with no args');
+
+	// @ts-expect-error
+	t.deepEqual(func(), [undefined, undefined, undefined], 'unbound func with too few args');
+	// @ts-expect-error
+	t.deepEqual(bound(1, 2), [hasStrictMode ? 1 : Object(1), 2, undefined], 'bound func too few args');
+	// @ts-expect-error
+	t.deepEqual(boundR(), [sentinel, undefined, undefined], 'bound func with receiver, with too few args');
+	// @ts-expect-error
+	t.deepEqual(boundArg(), [sentinel, 1, undefined], 'bound func with receiver and arg, with too few args');
+
+	t.deepEqual(func(1, 2), [undefined, 1, 2], 'unbound func with right args');
+	t.deepEqual(bound(1, 2, 3), [hasStrictMode ? 1 : Object(1), 2, 3], 'bound func with right args');
+	t.deepEqual(boundR(1, 2), [sentinel, 1, 2], 'bound func with receiver, with right args');
+	t.deepEqual(boundArg(2), [sentinel, 1, 2], 'bound func with receiver and arg, with right arg');
+
+	// @ts-expect-error
+	t.deepEqual(func(1, 2, 3), [undefined, 1, 2], 'unbound func with too many args');
+	// @ts-expect-error
+	t.deepEqual(bound(1, 2, 3, 4), [hasStrictMode ? 1 : Object(1), 2, 3], 'bound func with too many args');
+	// @ts-expect-error
+	t.deepEqual(boundR(1, 2, 3), [sentinel, 1, 2], 'bound func with receiver, with too many args');
+	// @ts-expect-error
+	t.deepEqual(boundArg(2, 3), [sentinel, 1, 2], 'bound func with receiver and arg, with too many args');
+
+	t.end();
+});
diff --git a/server/node_modules/call-bind-apply-helpers/tsconfig.json b/server/node_modules/call-bind-apply-helpers/tsconfig.json
new file mode 100644
index 0000000..aef9993
--- /dev/null
+++ b/server/node_modules/call-bind-apply-helpers/tsconfig.json
@@ -0,0 +1,9 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "es2021",
+	},
+	"exclude": [
+		"coverage",
+	],
+}
\ No newline at end of file
diff --git a/server/node_modules/call-bound/.eslintrc b/server/node_modules/call-bound/.eslintrc
new file mode 100644
index 0000000..2612ed8
--- /dev/null
+++ b/server/node_modules/call-bound/.eslintrc
@@ -0,0 +1,13 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"new-cap": [2, {
+			"capIsNewExceptions": [
+				"GetIntrinsic",
+			],
+		}],
+	},
+}
diff --git a/server/node_modules/call-bound/.github/FUNDING.yml b/server/node_modules/call-bound/.github/FUNDING.yml
new file mode 100644
index 0000000..2a2a135
--- /dev/null
+++ b/server/node_modules/call-bound/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/call-bound
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/call-bound/.nycrc b/server/node_modules/call-bound/.nycrc
new file mode 100644
index 0000000..bdd626c
--- /dev/null
+++ b/server/node_modules/call-bound/.nycrc
@@ -0,0 +1,9 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/call-bound/CHANGELOG.md b/server/node_modules/call-bound/CHANGELOG.md
new file mode 100644
index 0000000..8bde4e9
--- /dev/null
+++ b/server/node_modules/call-bound/CHANGELOG.md
@@ -0,0 +1,42 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.0.4](https://github.com/ljharb/call-bound/compare/v1.0.3...v1.0.4) - 2025-03-03
+
+### Commits
+
+- [types] improve types [`e648922`](https://github.com/ljharb/call-bound/commit/e6489222a9e54f350fbf952ceabe51fd8b6027ff)
+- [Dev Deps] update `@arethetypeswrong/cli`, `@ljharb/tsconfig`, `@types/tape`, `es-value-fixtures`, `for-each`, `has-strict-mode`, `object-inspect` [`a42a5eb`](https://github.com/ljharb/call-bound/commit/a42a5ebe6c1b54fcdc7997c7dc64fdca9e936719)
+- [Deps] update `call-bind-apply-helpers`, `get-intrinsic` [`f529eac`](https://github.com/ljharb/call-bound/commit/f529eac132404c17156bbc23ab2297a25d0f20b8)
+
+## [v1.0.3](https://github.com/ljharb/call-bound/compare/v1.0.2...v1.0.3) - 2024-12-15
+
+### Commits
+
+- [Refactor] use `call-bind-apply-helpers` instead of `call-bind` [`5e0b134`](https://github.com/ljharb/call-bound/commit/5e0b13496df14fb7d05dae9412f088da8d3f75be)
+- [Deps] update `get-intrinsic` [`41fc967`](https://github.com/ljharb/call-bound/commit/41fc96732a22c7b7e8f381f93ccc54bb6293be2e)
+- [readme] fix example [`79a0137`](https://github.com/ljharb/call-bound/commit/79a0137723f7c6d09c9c05452bbf8d5efb5d6e49)
+- [meta] add `sideEffects` flag [`08b07be`](https://github.com/ljharb/call-bound/commit/08b07be7f1c03f67dc6f3cdaf0906259771859f7)
+
+## [v1.0.2](https://github.com/ljharb/call-bound/compare/v1.0.1...v1.0.2) - 2024-12-10
+
+### Commits
+
+- [Dev Deps] update `@arethetypeswrong/cli`, `@ljharb/tsconfig`, `gopd` [`e6a5ffe`](https://github.com/ljharb/call-bound/commit/e6a5ffe849368fe4f74dfd6cdeca1b9baa39e8d5)
+- [Deps] update `call-bind`, `get-intrinsic` [`2aeb5b5`](https://github.com/ljharb/call-bound/commit/2aeb5b521dc2b2683d1345c753ea1161de2d1c14)
+- [types] improve return type [`1a0c9fe`](https://github.com/ljharb/call-bound/commit/1a0c9fe3114471e7ca1f57d104e2efe713bb4871)
+
+## v1.0.1 - 2024-12-05
+
+### Commits
+
+- Initial implementation, tests, readme, types [`6d94121`](https://github.com/ljharb/call-bound/commit/6d94121a9243602e506334069f7a03189fe3363d)
+- Initial commit [`0eae867`](https://github.com/ljharb/call-bound/commit/0eae867334ea025c33e6e91cdecfc9df96680cf9)
+- npm init [`71b2479`](https://github.com/ljharb/call-bound/commit/71b2479c6723e0b7d91a6b663613067e98b7b275)
+- Only apps should have lockfiles [`c3754a9`](https://github.com/ljharb/call-bound/commit/c3754a949b7f9132b47e2d18c1729889736741eb)
+- [actions] skip `npm ls` in node < 10 [`74275a5`](https://github.com/ljharb/call-bound/commit/74275a5186b8caf6309b6b97472bdcb0df4683a8)
+- [Dev Deps] add missing peer dep [`1354de8`](https://github.com/ljharb/call-bound/commit/1354de8679413e4ae9c523d85f76fa7a5e032d97)
diff --git a/server/node_modules/call-bound/LICENSE b/server/node_modules/call-bound/LICENSE
new file mode 100644
index 0000000..f82f389
--- /dev/null
+++ b/server/node_modules/call-bound/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/call-bound/README.md b/server/node_modules/call-bound/README.md
new file mode 100644
index 0000000..a44e43e
--- /dev/null
+++ b/server/node_modules/call-bound/README.md
@@ -0,0 +1,53 @@
+# call-bound <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![dependency status][deps-svg]][deps-url]
+[![dev dependency status][dev-deps-svg]][dev-deps-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+Robust call-bound JavaScript intrinsics, using `call-bind` and `get-intrinsic`.
+
+## Getting started
+
+```sh
+npm install --save call-bound
+```
+
+## Usage/Examples
+
+```js
+const assert = require('assert');
+const callBound = require('call-bound');
+
+const slice = callBound('Array.prototype.slice');
+
+delete Function.prototype.call;
+delete Function.prototype.bind;
+delete Array.prototype.slice;
+
+assert.deepEqual(slice([1, 2, 3, 4], 1, -1), [2, 3]);
+```
+
+## Tests
+
+Clone the repo, `npm install`, and run `npm test`
+
+[package-url]: https://npmjs.org/package/call-bound
+[npm-version-svg]: https://versionbadg.es/ljharb/call-bound.svg
+[deps-svg]: https://david-dm.org/ljharb/call-bound.svg
+[deps-url]: https://david-dm.org/ljharb/call-bound
+[dev-deps-svg]: https://david-dm.org/ljharb/call-bound/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/call-bound#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/call-bound.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/call-bound.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/call-bound.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=call-bound
+[codecov-image]: https://codecov.io/gh/ljharb/call-bound/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/call-bound/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/call-bound
+[actions-url]: https://github.com/ljharb/call-bound/actions
diff --git a/server/node_modules/call-bound/index.d.ts b/server/node_modules/call-bound/index.d.ts
new file mode 100644
index 0000000..5562f00
--- /dev/null
+++ b/server/node_modules/call-bound/index.d.ts
@@ -0,0 +1,94 @@
+type Intrinsic = typeof globalThis;
+
+type IntrinsicName = keyof Intrinsic | `%${keyof Intrinsic}%`;
+
+type IntrinsicPath = IntrinsicName | `${StripPercents<IntrinsicName>}.${string}` | `%${StripPercents<IntrinsicName>}.${string}%`;
+
+type AllowMissing = boolean;
+
+type StripPercents<T extends string> = T extends `%${infer U}%` ? U : T;
+
+type BindMethodPrecise<F> =
+  F extends (this: infer This, ...args: infer Args) => infer R
+  ? (obj: This, ...args: Args) => R
+  : F extends {
+    (this: infer This1, ...args: infer Args1): infer R1;
+    (this: infer This2, ...args: infer Args2): infer R2
+  }
+  ? {
+    (obj: This1, ...args: Args1): R1;
+    (obj: This2, ...args: Args2): R2
+  }
+  : never
+
+// Extract method type from a prototype
+type GetPrototypeMethod<T extends keyof typeof globalThis, M extends string> =
+  (typeof globalThis)[T] extends { prototype: any }
+  ? M extends keyof (typeof globalThis)[T]['prototype']
+  ? (typeof globalThis)[T]['prototype'][M]
+  : never
+  : never
+
+// Get static property/method
+type GetStaticMember<T extends keyof typeof globalThis, P extends string> =
+  P extends keyof (typeof globalThis)[T] ? (typeof globalThis)[T][P] : never
+
+// Type that maps string path to actual bound function or value with better precision
+type BoundIntrinsic<S extends string> =
+  S extends `${infer Obj}.prototype.${infer Method}`
+  ? Obj extends keyof typeof globalThis
+  ? BindMethodPrecise<GetPrototypeMethod<Obj, Method & string>>
+  : unknown
+  : S extends `${infer Obj}.${infer Prop}`
+  ? Obj extends keyof typeof globalThis
+  ? GetStaticMember<Obj, Prop & string>
+  : unknown
+  : unknown
+
+declare function arraySlice<T>(array: readonly T[], start?: number, end?: number): T[];
+declare function arraySlice<T>(array: ArrayLike<T>, start?: number, end?: number): T[];
+declare function arraySlice<T>(array: IArguments, start?: number, end?: number): T[];
+
+// Special cases for methods that need explicit typing
+interface SpecialCases {
+  '%Object.prototype.isPrototypeOf%': (thisArg: {}, obj: unknown) => boolean;
+  '%String.prototype.replace%': {
+    (str: string, searchValue: string | RegExp, replaceValue: string): string;
+    (str: string, searchValue: string | RegExp, replacer: (substring: string, ...args: any[]) => string): string
+  };
+  '%Object.prototype.toString%': (obj: {}) => string;
+  '%Object.prototype.hasOwnProperty%': (obj: {}, v: PropertyKey) => boolean;
+  '%Array.prototype.slice%': typeof arraySlice;
+  '%Array.prototype.map%': <T, U>(array: readonly T[], callbackfn: (value: T, index: number, array: readonly T[]) => U, thisArg?: any) => U[];
+  '%Array.prototype.filter%': <T>(array: readonly T[], predicate: (value: T, index: number, array: readonly T[]) => unknown, thisArg?: any) => T[];
+  '%Array.prototype.indexOf%': <T>(array: readonly T[], searchElement: T, fromIndex?: number) => number;
+  '%Function.prototype.apply%': <T, A extends any[], R>(fn: (...args: A) => R, thisArg: any, args: A) => R;
+  '%Function.prototype.call%': <T, A extends any[], R>(fn: (...args: A) => R, thisArg: any, ...args: A) => R;
+  '%Function.prototype.bind%': <T, A extends any[], R>(fn: (...args: A) => R, thisArg: any, ...args: A) => (...remainingArgs: A) => R;
+  '%Promise.prototype.then%': {
+    <T, R>(promise: Promise<T>, onfulfilled: (value: T) => R | PromiseLike<R>): Promise<R>;
+    <T, R>(promise: Promise<T>, onfulfilled: ((value: T) => R | PromiseLike<R>) | undefined | null, onrejected: (reason: any) => R | PromiseLike<R>): Promise<R>;
+  };
+  '%RegExp.prototype.test%': (regexp: RegExp, str: string) => boolean;
+  '%RegExp.prototype.exec%': (regexp: RegExp, str: string) => RegExpExecArray | null;
+  '%Error.prototype.toString%': (error: Error) => string;
+  '%TypeError.prototype.toString%': (error: TypeError) => string;
+  '%String.prototype.split%': (
+        obj: unknown,
+        splitter: string | RegExp | {
+            [Symbol.split](string: string, limit?: number): string[];
+        },
+        limit?: number | undefined
+    ) => string[];
+}
+
+/**
+ * Returns a bound function for a prototype method, or a value for a static property.
+ *
+ * @param name - The name of the intrinsic (e.g. 'Array.prototype.slice')
+ * @param {AllowMissing} [allowMissing] - Whether to allow missing intrinsics (default: false)
+ */
+declare function callBound<K extends keyof SpecialCases | StripPercents<keyof SpecialCases>, S extends IntrinsicPath>(name: K, allowMissing?: AllowMissing): SpecialCases[`%${StripPercents<K>}%`];
+declare function callBound<K extends keyof SpecialCases | StripPercents<keyof SpecialCases>, S extends IntrinsicPath>(name: S, allowMissing?: AllowMissing): BoundIntrinsic<S>;
+
+export = callBound;
diff --git a/server/node_modules/call-bound/index.js b/server/node_modules/call-bound/index.js
new file mode 100644
index 0000000..e9ade74
--- /dev/null
+++ b/server/node_modules/call-bound/index.js
@@ -0,0 +1,19 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+
+var callBindBasic = require('call-bind-apply-helpers');
+
+/** @type {(thisArg: string, searchString: string, position?: number) => number} */
+var $indexOf = callBindBasic([GetIntrinsic('%String.prototype.indexOf%')]);
+
+/** @type {import('.')} */
+module.exports = function callBoundIntrinsic(name, allowMissing) {
+	/* eslint no-extra-parens: 0 */
+
+	var intrinsic = /** @type {(this: unknown, ...args: unknown[]) => unknown} */ (GetIntrinsic(name, !!allowMissing));
+	if (typeof intrinsic === 'function' && $indexOf(name, '.prototype.') > -1) {
+		return callBindBasic(/** @type {const} */ ([intrinsic]));
+	}
+	return intrinsic;
+};
diff --git a/server/node_modules/call-bound/package.json b/server/node_modules/call-bound/package.json
new file mode 100644
index 0000000..d542db4
--- /dev/null
+++ b/server/node_modules/call-bound/package.json
@@ -0,0 +1,99 @@
+{
+	"name": "call-bound",
+	"version": "1.0.4",
+	"description": "Robust call-bound JavaScript intrinsics, using `call-bind` and `get-intrinsic`.",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./package.json": "./package.json"
+	},
+	"sideEffects": false,
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=auto",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prepublishOnly": "safe-publish-latest",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=.js,.mjs .",
+		"postlint": "tsc -p . && attw -P",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>=10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/call-bound.git"
+	},
+	"keywords": [
+		"javascript",
+		"ecmascript",
+		"es",
+		"js",
+		"callbind",
+		"callbound",
+		"call",
+		"bind",
+		"bound",
+		"call-bind",
+		"call-bound",
+		"function",
+		"es-abstract"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"funding": {
+		"url": "https://github.com/sponsors/ljharb"
+	},
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/call-bound/issues"
+	},
+	"homepage": "https://github.com/ljharb/call-bound#readme",
+	"dependencies": {
+		"call-bind-apply-helpers": "^1.0.2",
+		"get-intrinsic": "^1.3.0"
+	},
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.4",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.3.0",
+		"@types/call-bind": "^1.0.5",
+		"@types/get-intrinsic": "^1.2.3",
+		"@types/tape": "^5.8.1",
+		"auto-changelog": "^2.5.0",
+		"encoding": "^0.1.13",
+		"es-value-fixtures": "^1.7.1",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"for-each": "^0.3.5",
+		"gopd": "^1.2.0",
+		"has-strict-mode": "^1.1.0",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"object-inspect": "^1.13.4",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"testling": {
+		"files": "test/index.js"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/call-bound/test/index.js b/server/node_modules/call-bound/test/index.js
new file mode 100644
index 0000000..a2fc9f0
--- /dev/null
+++ b/server/node_modules/call-bound/test/index.js
@@ -0,0 +1,61 @@
+'use strict';
+
+var test = require('tape');
+
+var callBound = require('../');
+
+/** @template {true} T @template U @typedef {T extends U ? T : never} AssertType */
+
+test('callBound', function (t) {
+	// static primitive
+	t.equal(callBound('Array.length'), Array.length, 'Array.length yields itself');
+	t.equal(callBound('%Array.length%'), Array.length, '%Array.length% yields itself');
+
+	// static non-function object
+	t.equal(callBound('Array.prototype'), Array.prototype, 'Array.prototype yields itself');
+	t.equal(callBound('%Array.prototype%'), Array.prototype, '%Array.prototype% yields itself');
+	t.equal(callBound('Array.constructor'), Array.constructor, 'Array.constructor yields itself');
+	t.equal(callBound('%Array.constructor%'), Array.constructor, '%Array.constructor% yields itself');
+
+	// static function
+	t.equal(callBound('Date.parse'), Date.parse, 'Date.parse yields itself');
+	t.equal(callBound('%Date.parse%'), Date.parse, '%Date.parse% yields itself');
+
+	// prototype primitive
+	t.equal(callBound('Error.prototype.message'), Error.prototype.message, 'Error.prototype.message yields itself');
+	t.equal(callBound('%Error.prototype.message%'), Error.prototype.message, '%Error.prototype.message% yields itself');
+
+	var x = callBound('Object.prototype.toString');
+	var y = callBound('%Object.prototype.toString%');
+
+	// prototype function
+	t.notEqual(x, Object.prototype.toString, 'Object.prototype.toString does not yield itself');
+	t.notEqual(y, Object.prototype.toString, '%Object.prototype.toString% does not yield itself');
+	t.equal(x(true), Object.prototype.toString.call(true), 'call-bound Object.prototype.toString calls into the original');
+	t.equal(y(true), Object.prototype.toString.call(true), 'call-bound %Object.prototype.toString% calls into the original');
+
+	t['throws'](
+		// @ts-expect-error
+		function () { callBound('does not exist'); },
+		SyntaxError,
+		'nonexistent intrinsic throws'
+	);
+	t['throws'](
+		// @ts-expect-error
+		function () { callBound('does not exist', true); },
+		SyntaxError,
+		'allowMissing arg still throws for unknown intrinsic'
+	);
+
+	t.test('real but absent intrinsic', { skip: typeof WeakRef !== 'undefined' }, function (st) {
+		st['throws'](
+			function () { callBound('WeakRef'); },
+			TypeError,
+			'real but absent intrinsic throws'
+		);
+		st.equal(callBound('WeakRef', true), undefined, 'allowMissing arg avoids exception');
+		st.end();
+	});
+
+	t.end();
+});
diff --git a/server/node_modules/call-bound/tsconfig.json b/server/node_modules/call-bound/tsconfig.json
new file mode 100644
index 0000000..8976d98
--- /dev/null
+++ b/server/node_modules/call-bound/tsconfig.json
@@ -0,0 +1,10 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "ESNext",
+		"lib": ["es2024"],
+	},
+	"exclude": [
+		"coverage",
+	],
+}
diff --git a/server/node_modules/chownr/LICENSE b/server/node_modules/chownr/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/chownr/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/chownr/README.md b/server/node_modules/chownr/README.md
new file mode 100644
index 0000000..70e9a54
--- /dev/null
+++ b/server/node_modules/chownr/README.md
@@ -0,0 +1,3 @@
+Like `chown -R`.
+
+Takes the same arguments as `fs.chown()`
diff --git a/server/node_modules/chownr/chownr.js b/server/node_modules/chownr/chownr.js
new file mode 100644
index 0000000..0d40932
--- /dev/null
+++ b/server/node_modules/chownr/chownr.js
@@ -0,0 +1,167 @@
+'use strict'
+const fs = require('fs')
+const path = require('path')
+
+/* istanbul ignore next */
+const LCHOWN = fs.lchown ? 'lchown' : 'chown'
+/* istanbul ignore next */
+const LCHOWNSYNC = fs.lchownSync ? 'lchownSync' : 'chownSync'
+
+/* istanbul ignore next */
+const needEISDIRHandled = fs.lchown &&
+  !process.version.match(/v1[1-9]+\./) &&
+  !process.version.match(/v10\.[6-9]/)
+
+const lchownSync = (path, uid, gid) => {
+  try {
+    return fs[LCHOWNSYNC](path, uid, gid)
+  } catch (er) {
+    if (er.code !== 'ENOENT')
+      throw er
+  }
+}
+
+/* istanbul ignore next */
+const chownSync = (path, uid, gid) => {
+  try {
+    return fs.chownSync(path, uid, gid)
+  } catch (er) {
+    if (er.code !== 'ENOENT')
+      throw er
+  }
+}
+
+/* istanbul ignore next */
+const handleEISDIR =
+  needEISDIRHandled ? (path, uid, gid, cb) => er => {
+    // Node prior to v10 had a very questionable implementation of
+    // fs.lchown, which would always try to call fs.open on a directory
+    // Fall back to fs.chown in those cases.
+    if (!er || er.code !== 'EISDIR')
+      cb(er)
+    else
+      fs.chown(path, uid, gid, cb)
+  }
+  : (_, __, ___, cb) => cb
+
+/* istanbul ignore next */
+const handleEISDirSync =
+  needEISDIRHandled ? (path, uid, gid) => {
+    try {
+      return lchownSync(path, uid, gid)
+    } catch (er) {
+      if (er.code !== 'EISDIR')
+        throw er
+      chownSync(path, uid, gid)
+    }
+  }
+  : (path, uid, gid) => lchownSync(path, uid, gid)
+
+// fs.readdir could only accept an options object as of node v6
+const nodeVersion = process.version
+let readdir = (path, options, cb) => fs.readdir(path, options, cb)
+let readdirSync = (path, options) => fs.readdirSync(path, options)
+/* istanbul ignore next */
+if (/^v4\./.test(nodeVersion))
+  readdir = (path, options, cb) => fs.readdir(path, cb)
+
+const chown = (cpath, uid, gid, cb) => {
+  fs[LCHOWN](cpath, uid, gid, handleEISDIR(cpath, uid, gid, er => {
+    // Skip ENOENT error
+    cb(er && er.code !== 'ENOENT' ? er : null)
+  }))
+}
+
+const chownrKid = (p, child, uid, gid, cb) => {
+  if (typeof child === 'string')
+    return fs.lstat(path.resolve(p, child), (er, stats) => {
+      // Skip ENOENT error
+      if (er)
+        return cb(er.code !== 'ENOENT' ? er : null)
+      stats.name = child
+      chownrKid(p, stats, uid, gid, cb)
+    })
+
+  if (child.isDirectory()) {
+    chownr(path.resolve(p, child.name), uid, gid, er => {
+      if (er)
+        return cb(er)
+      const cpath = path.resolve(p, child.name)
+      chown(cpath, uid, gid, cb)
+    })
+  } else {
+    const cpath = path.resolve(p, child.name)
+    chown(cpath, uid, gid, cb)
+  }
+}
+
+
+const chownr = (p, uid, gid, cb) => {
+  readdir(p, { withFileTypes: true }, (er, children) => {
+    // any error other than ENOTDIR or ENOTSUP means it's not readable,
+    // or doesn't exist.  give up.
+    if (er) {
+      if (er.code === 'ENOENT')
+        return cb()
+      else if (er.code !== 'ENOTDIR' && er.code !== 'ENOTSUP')
+        return cb(er)
+    }
+    if (er || !children.length)
+      return chown(p, uid, gid, cb)
+
+    let len = children.length
+    let errState = null
+    const then = er => {
+      if (errState)
+        return
+      if (er)
+        return cb(errState = er)
+      if (-- len === 0)
+        return chown(p, uid, gid, cb)
+    }
+
+    children.forEach(child => chownrKid(p, child, uid, gid, then))
+  })
+}
+
+const chownrKidSync = (p, child, uid, gid) => {
+  if (typeof child === 'string') {
+    try {
+      const stats = fs.lstatSync(path.resolve(p, child))
+      stats.name = child
+      child = stats
+    } catch (er) {
+      if (er.code === 'ENOENT')
+        return
+      else
+        throw er
+    }
+  }
+
+  if (child.isDirectory())
+    chownrSync(path.resolve(p, child.name), uid, gid)
+
+  handleEISDirSync(path.resolve(p, child.name), uid, gid)
+}
+
+const chownrSync = (p, uid, gid) => {
+  let children
+  try {
+    children = readdirSync(p, { withFileTypes: true })
+  } catch (er) {
+    if (er.code === 'ENOENT')
+      return
+    else if (er.code === 'ENOTDIR' || er.code === 'ENOTSUP')
+      return handleEISDirSync(p, uid, gid)
+    else
+      throw er
+  }
+
+  if (children && children.length)
+    children.forEach(child => chownrKidSync(p, child, uid, gid))
+
+  return handleEISDirSync(p, uid, gid)
+}
+
+module.exports = chownr
+chownr.sync = chownrSync
diff --git a/server/node_modules/chownr/package.json b/server/node_modules/chownr/package.json
new file mode 100644
index 0000000..c273a7d
--- /dev/null
+++ b/server/node_modules/chownr/package.json
@@ -0,0 +1,29 @@
+{
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "name": "chownr",
+  "description": "like `chown -R`",
+  "version": "1.1.4",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/isaacs/chownr.git"
+  },
+  "main": "chownr.js",
+  "files": [
+    "chownr.js"
+  ],
+  "devDependencies": {
+    "mkdirp": "0.3",
+    "rimraf": "^2.7.1",
+    "tap": "^14.10.6"
+  },
+  "tap": {
+    "check-coverage": true
+  },
+  "scripts": {
+    "test": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags"
+  },
+  "license": "ISC"
+}
diff --git a/server/node_modules/clean-stack/index.d.ts b/server/node_modules/clean-stack/index.d.ts
new file mode 100644
index 0000000..ed58995
--- /dev/null
+++ b/server/node_modules/clean-stack/index.d.ts
@@ -0,0 +1,47 @@
+declare namespace cleanStack {
+	interface Options {
+		/**
+		Prettify the file paths in the stack:
+
+		`/Users/sindresorhus/dev/clean-stack/unicorn.js:2:15` → `~/dev/clean-stack/unicorn.js:2:15`
+
+		@default false
+		*/
+		readonly pretty?: boolean;
+	}
+}
+
+/**
+Clean up error stack traces. Removes the mostly unhelpful internal Node.js entries.
+
+@param stack - The `stack` property of an `Error`.
+
+@example
+```
+import cleanStack = require('clean-stack');
+
+const error = new Error('Missing unicorn');
+
+console.log(error.stack);
+
+// Error: Missing unicorn
+//     at Object.<anonymous> (/Users/sindresorhus/dev/clean-stack/unicorn.js:2:15)
+//     at Module._compile (module.js:409:26)
+//     at Object.Module._extensions..js (module.js:416:10)
+//     at Module.load (module.js:343:32)
+//     at Function.Module._load (module.js:300:12)
+//     at Function.Module.runMain (module.js:441:10)
+//     at startup (node.js:139:18)
+
+console.log(cleanStack(error.stack));
+
+// Error: Missing unicorn
+//     at Object.<anonymous> (/Users/sindresorhus/dev/clean-stack/unicorn.js:2:15)
+```
+*/
+declare function cleanStack(
+	stack: string,
+	options?: cleanStack.Options
+): string;
+
+export = cleanStack;
diff --git a/server/node_modules/clean-stack/index.js b/server/node_modules/clean-stack/index.js
new file mode 100644
index 0000000..8c1dcc4
--- /dev/null
+++ b/server/node_modules/clean-stack/index.js
@@ -0,0 +1,40 @@
+'use strict';
+const os = require('os');
+
+const extractPathRegex = /\s+at.*(?:$|\s)(.*)$?/;
+const pathRegex = /^(?:(?:(?:node|(?:internal\/[\w/]*|.*node_modules\/(?:babel-polyfill|pirates)\/.*)?\w+)\.js:\d+:\d+)|native)/;
+const homeDir = typeof os.homedir === 'undefined' ? '' : os.homedir();
+
+module.exports = (stack, options) => {
+	options = Object.assign({pretty: false}, options);
+
+	return stack.replace(/\\/g, '/')
+		.split('\n')
+		.filter(line => {
+			const pathMatches = line.match(extractPathRegex);
+			if (pathMatches === null || !pathMatches[1]) {
+				return true;
+			}
+
+			const match = pathMatches[1];
+
+			// Electron
+			if (
+				match.includes('.app/Contents/Resources/electron.asar') ||
+				match.includes('.app/Contents/Resources/default_app.asar')
+			) {
+				return false;
+			}
+
+			return !pathRegex.test(match);
+		})
+		.filter(line => line.trim() !== '')
+		.map(line => {
+			if (options.pretty) {
+				return line.replace(extractPathRegex, (m, p1) => m.replace(p1, p1.replace(homeDir, '~')));
+			}
+
+			return line;
+		})
+		.join('\n');
+};
diff --git a/server/node_modules/clean-stack/license b/server/node_modules/clean-stack/license
new file mode 100644
index 0000000..e7af2f7
--- /dev/null
+++ b/server/node_modules/clean-stack/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/clean-stack/package.json b/server/node_modules/clean-stack/package.json
new file mode 100644
index 0000000..719fdff
--- /dev/null
+++ b/server/node_modules/clean-stack/package.json
@@ -0,0 +1,39 @@
+{
+	"name": "clean-stack",
+	"version": "2.2.0",
+	"description": "Clean up error stack traces",
+	"license": "MIT",
+	"repository": "sindresorhus/clean-stack",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=6"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"clean",
+		"stack",
+		"trace",
+		"traces",
+		"error",
+		"err",
+		"electron"
+	],
+	"devDependencies": {
+		"ava": "^1.4.1",
+		"tsd": "^0.7.2",
+		"xo": "^0.24.0"
+	},
+	"browser": {
+		"os": false
+	}
+}
diff --git a/server/node_modules/clean-stack/readme.md b/server/node_modules/clean-stack/readme.md
new file mode 100644
index 0000000..8d44160
--- /dev/null
+++ b/server/node_modules/clean-stack/readme.md
@@ -0,0 +1,76 @@
+# clean-stack [![Build Status](https://travis-ci.org/sindresorhus/clean-stack.svg?branch=master)](https://travis-ci.org/sindresorhus/clean-stack)
+
+> Clean up error stack traces
+
+Removes the mostly unhelpful internal Node.js entries.
+
+Also works in Electron.
+
+
+## Install
+
+```
+$ npm install clean-stack
+```
+
+
+## Usage
+
+```js
+const cleanStack = require('clean-stack');
+
+const error = new Error('Missing unicorn');
+
+console.log(error.stack);
+/*
+Error: Missing unicorn
+    at Object.<anonymous> (/Users/sindresorhus/dev/clean-stack/unicorn.js:2:15)
+    at Module._compile (module.js:409:26)
+    at Object.Module._extensions..js (module.js:416:10)
+    at Module.load (module.js:343:32)
+    at Function.Module._load (module.js:300:12)
+    at Function.Module.runMain (module.js:441:10)
+    at startup (node.js:139:18)
+*/
+
+console.log(cleanStack(error.stack));
+/*
+Error: Missing unicorn
+    at Object.<anonymous> (/Users/sindresorhus/dev/clean-stack/unicorn.js:2:15)
+*/
+```
+
+
+## API
+
+### cleanStack(stack, [options])
+
+#### stack
+
+Type: `string`
+
+The `stack` property of an `Error`.
+
+#### options
+
+Type: `Object`
+
+##### pretty
+
+Type: `boolean`<br>
+Default: `false`
+
+Prettify the file paths in the stack:
+
+`/Users/sindresorhus/dev/clean-stack/unicorn.js:2:15` → `~/dev/clean-stack/unicorn.js:2:15`
+
+
+## Related
+
+- [extrack-stack](https://github.com/sindresorhus/extract-stack) - Extract the actual stack of an error
+- [stack-utils](https://github.com/tapjs/stack-utils) - Captures and cleans stack traces
+
+
+## License
+
+MIT © [Sindre Sorhus](https://sindresorhus.com)
diff --git a/server/node_modules/color-support/LICENSE b/server/node_modules/color-support/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/color-support/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/color-support/README.md b/server/node_modules/color-support/README.md
new file mode 100644
index 0000000..f89aa17
--- /dev/null
+++ b/server/node_modules/color-support/README.md
@@ -0,0 +1,129 @@
+# color-support
+
+A module which will endeavor to guess your terminal's level of color
+support.
+
+[![Build Status](https://travis-ci.org/isaacs/color-support.svg?branch=master)](https://travis-ci.org/isaacs/color-support) [![Coverage Status](https://coveralls.io/repos/github/isaacs/color-support/badge.svg?branch=master)](https://coveralls.io/github/isaacs/color-support?branch=master)
+
+This is similar to `supports-color`, but it does not read
+`process.argv`.
+
+1. If not in a node environment, not supported.
+
+2. If stdout is not a TTY, not supported, unless the `ignoreTTY`
+   option is set.
+
+3. If the `TERM` environ is `dumb`, not supported, unless the
+   `ignoreDumb` option is set.
+
+4. If on Windows, then support 16 colors.
+
+5. If using Tmux, then support 256 colors.
+
+7. Handle continuous-integration servers.  If `CI` or
+   `TEAMCITY_VERSION` are set in the environment, and `TRAVIS` is not
+   set, then color is not supported, unless `ignoreCI` option is set.
+
+6. Guess based on the `TERM_PROGRAM` environ.  These terminals support
+   16m colors:
+
+    - `iTerm.app` version 3.x supports 16m colors, below support 256
+    - `MacTerm` supports 16m colors
+    - `Apple_Terminal` supports 256 colors
+    - Have more things that belong on this list?  Send a PR!
+
+8. Make a guess based on the `TERM` environment variable.  Any
+   `xterm-256color` will get 256 colors.  Any screen, xterm, vt100,
+   color, ansi, cygwin, or linux `TERM` will get 16 colors.
+
+9. If `COLORTERM` environment variable is set, then support 16 colors.
+
+10. At this point, we assume that color is not supported.
+
+## USAGE
+
+```javascript
+var testColorSupport = require('color-support')
+var colorSupport = testColorSupport(/* options object */)
+
+if (!colorSupport) {
+  console.log('color is not supported')
+} else if (colorSupport.has16m) {
+  console.log('\x1b[38;2;102;194;255m16m colors\x1b[0m')
+} else if (colorSupport.has256) {
+  console.log('\x1b[38;5;119m256 colors\x1b[0m')
+} else if (colorSupport.hasBasic) {
+  console.log('\x1b[31mbasic colors\x1b[0m')
+} else {
+  console.log('this is impossible, but colors are not supported')
+}
+```
+
+If you don't have any options to set, you can also just look at the
+flags which will all be set on the test function itself.  (Of course,
+this doesn't return a falsey value when colors aren't supported, and
+doesn't allow you to set options.)
+
+```javascript
+var colorSupport = require('color-support')
+
+if (colorSupport.has16m) {
+  console.log('\x1b[38;2;102;194;255m16m colors\x1b[0m')
+} else if (colorSupport.has256) {
+  console.log('\x1b[38;5;119m256 colors\x1b[0m')
+} else if (colorSupport.hasBasic) {
+  console.log('\x1b[31mbasic colors\x1b[0m')
+} else {
+  console.log('colors are not supported')
+}
+```
+
+## Options
+
+You can pass in the following options.
+
+* ignoreTTY - default false.  Ignore the `isTTY` check.
+* ignoreDumb - default false.  Ignore `TERM=dumb` environ check.
+* ignoreCI - default false.  Ignore `CI` environ check.
+* env - Object for environment vars. Defaults to `process.env`.
+* stream - Stream for `isTTY` check. Defaults to `process.stdout`.
+* term - String for `TERM` checking. Defaults to `env.TERM`.
+* alwaysReturn - default false.  Return an object when colors aren't
+  supported (instead of returning `false`).
+* level - A number from 0 to 3.  This will return a result for the
+  specified level.  This is useful if you want to be able to set the
+  color support level explicitly as a number in an environment
+  variable or config, but then use the object flags in your program.
+  Except for `alwaysReturn` to return an object for level 0, all other
+  options are ignored, since no checking is done if a level is
+  explicitly set.
+
+## Return Value
+
+If no color support is available, then `false` is returned by default,
+unless the `alwaysReturn` flag is set to `true`.  This is so that the
+simple question of "can I use colors or not" can treat any truthy
+return as "yes".
+
+Otherwise, the return object has the following fields:
+
+* `level` - A number from 0 to 3
+    * `0` - No color support
+    * `1` - Basic (16) color support
+    * `2` - 256 color support
+    * `3` - 16 million (true) color support
+* `hasBasic` - Boolean
+* `has256` - Boolean
+* `has16m` - Boolean
+
+## CLI
+
+You can run the `color-support` bin from the command line which will
+just dump the values as this module calculates them in whatever env
+it's run.  It takes no command line arguments.
+
+## Credits
+
+This is a spiritual, if not actual, fork of
+[supports-color](http://npm.im/supports-color) by the ever prolific
+[Sindre Sorhus](http://npm.im/~sindresorhus).
diff --git a/server/node_modules/color-support/bin.js b/server/node_modules/color-support/bin.js
new file mode 100755
index 0000000..3c0a967
--- /dev/null
+++ b/server/node_modules/color-support/bin.js
@@ -0,0 +1,3 @@
+#!/usr/bin/env node
+var colorSupport = require('./')({alwaysReturn: true })
+console.log(JSON.stringify(colorSupport, null, 2))
diff --git a/server/node_modules/color-support/browser.js b/server/node_modules/color-support/browser.js
new file mode 100644
index 0000000..ab5c663
--- /dev/null
+++ b/server/node_modules/color-support/browser.js
@@ -0,0 +1,14 @@
+module.exports = colorSupport({ alwaysReturn: true }, colorSupport)
+
+function colorSupport(options, obj) {
+  obj = obj || {}
+  options = options || {}
+  obj.level = 0
+  obj.hasBasic = false
+  obj.has256 = false
+  obj.has16m = false
+  if (!options.alwaysReturn) {
+    return false
+  }
+  return obj
+}
diff --git a/server/node_modules/color-support/index.js b/server/node_modules/color-support/index.js
new file mode 100644
index 0000000..6b6f3b2
--- /dev/null
+++ b/server/node_modules/color-support/index.js
@@ -0,0 +1,134 @@
+// call it on itself so we can test the export val for basic stuff
+module.exports = colorSupport({ alwaysReturn: true }, colorSupport)
+
+function hasNone (obj, options) {
+  obj.level = 0
+  obj.hasBasic = false
+  obj.has256 = false
+  obj.has16m = false
+  if (!options.alwaysReturn) {
+    return false
+  }
+  return obj
+}
+
+function hasBasic (obj) {
+  obj.hasBasic = true
+  obj.has256 = false
+  obj.has16m = false
+  obj.level = 1
+  return obj
+}
+
+function has256 (obj) {
+  obj.hasBasic = true
+  obj.has256 = true
+  obj.has16m = false
+  obj.level = 2
+  return obj
+}
+
+function has16m (obj) {
+  obj.hasBasic = true
+  obj.has256 = true
+  obj.has16m = true
+  obj.level = 3
+  return obj
+}
+
+function colorSupport (options, obj) {
+  options = options || {}
+
+  obj = obj || {}
+
+  // if just requesting a specific level, then return that.
+  if (typeof options.level === 'number') {
+    switch (options.level) {
+      case 0:
+        return hasNone(obj, options)
+      case 1:
+        return hasBasic(obj)
+      case 2:
+        return has256(obj)
+      case 3:
+        return has16m(obj)
+    }
+  }
+
+  obj.level = 0
+  obj.hasBasic = false
+  obj.has256 = false
+  obj.has16m = false
+
+  if (typeof process === 'undefined' ||
+      !process ||
+      !process.stdout ||
+      !process.env ||
+      !process.platform) {
+    return hasNone(obj, options)
+  }
+
+  var env = options.env || process.env
+  var stream = options.stream || process.stdout
+  var term = options.term || env.TERM || ''
+  var platform = options.platform || process.platform
+
+  if (!options.ignoreTTY && !stream.isTTY) {
+    return hasNone(obj, options)
+  }
+
+  if (!options.ignoreDumb && term === 'dumb' && !env.COLORTERM) {
+    return hasNone(obj, options)
+  }
+
+  if (platform === 'win32') {
+    return hasBasic(obj)
+  }
+
+  if (env.TMUX) {
+    return has256(obj)
+  }
+
+  if (!options.ignoreCI && (env.CI || env.TEAMCITY_VERSION)) {
+    if (env.TRAVIS) {
+      return has256(obj)
+    } else {
+      return hasNone(obj, options)
+    }
+  }
+
+  // TODO: add more term programs
+  switch (env.TERM_PROGRAM) {
+    case 'iTerm.app':
+      var ver = env.TERM_PROGRAM_VERSION || '0.'
+      if (/^[0-2]\./.test(ver)) {
+        return has256(obj)
+      } else {
+        return has16m(obj)
+      }
+
+    case 'HyperTerm':
+    case 'Hyper':
+      return has16m(obj)
+
+    case 'MacTerm':
+      return has16m(obj)
+
+    case 'Apple_Terminal':
+      return has256(obj)
+  }
+
+  if (/^xterm-256/.test(term)) {
+    return has256(obj)
+  }
+
+  if (/^screen|^xterm|^vt100|color|ansi|cygwin|linux/i.test(term)) {
+    return hasBasic(obj)
+  }
+
+  if (env.COLORTERM) {
+    return hasBasic(obj)
+  }
+
+  return hasNone(obj, options)
+}
diff --git a/server/node_modules/color-support/package.json b/server/node_modules/color-support/package.json
new file mode 100644
index 0000000..f3e3b77
--- /dev/null
+++ b/server/node_modules/color-support/package.json
@@ -0,0 +1,36 @@
+{
+  "name": "color-support",
+  "version": "1.1.3",
+  "description": "A module which will endeavor to guess your terminal's level of color support.",
+  "main": "index.js",
+  "browser": "browser.js",
+  "bin": "bin.js",
+  "devDependencies": {
+    "tap": "^10.3.3"
+  },
+  "scripts": {
+    "test": "tap test/*.js --100 -J",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --all; git push origin --tags"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/isaacs/color-support.git"
+  },
+  "keywords": [
+    "terminal",
+    "color",
+    "support",
+    "xterm",
+    "truecolor",
+    "256"
+  ],
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC",
+  "files": [
+    "browser.js",
+    "index.js",
+    "bin.js"
+  ]
+}
diff --git a/server/node_modules/concat-map/.travis.yml b/server/node_modules/concat-map/.travis.yml
new file mode 100644
index 0000000..f1d0f13
--- /dev/null
+++ b/server/node_modules/concat-map/.travis.yml
@@ -0,0 +1,4 @@
+language: node_js
+node_js:
+  - 0.4
+  - 0.6
diff --git a/server/node_modules/concat-map/LICENSE b/server/node_modules/concat-map/LICENSE
new file mode 100644
index 0000000..ee27ba4
--- /dev/null
+++ b/server/node_modules/concat-map/LICENSE
@@ -0,0 +1,18 @@
+This software is released under the MIT license:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/concat-map/README.markdown b/server/node_modules/concat-map/README.markdown
new file mode 100644
index 0000000..408f70a
--- /dev/null
+++ b/server/node_modules/concat-map/README.markdown
@@ -0,0 +1,62 @@
+concat-map
+==========
+
+Concatenative mapdashery.
+
+[![browser support](http://ci.testling.com/substack/node-concat-map.png)](http://ci.testling.com/substack/node-concat-map)
+
+[![build status](https://secure.travis-ci.org/substack/node-concat-map.png)](http://travis-ci.org/substack/node-concat-map)
+
+example
+=======
+
+``` js
+var concatMap = require('concat-map');
+var xs = [ 1, 2, 3, 4, 5, 6 ];
+var ys = concatMap(xs, function (x) {
+    return x % 2 ? [ x - 0.1, x, x + 0.1 ] : [];
+});
+console.dir(ys);
+```
+
+***
+
+```
+[ 0.9, 1, 1.1, 2.9, 3, 3.1, 4.9, 5, 5.1 ]
+```
+
+methods
+=======
+
+``` js
+var concatMap = require('concat-map')
+```
+
+concatMap(xs, fn)
+-----------------
+
+Return an array of concatenated elements by calling `fn(x, i)` for each element
+`x` and each index `i` in the array `xs`.
+
+When `fn(x, i)` returns an array, its result will be concatenated with the
+result array. If `fn(x, i)` returns anything else, that value will be pushed
+onto the end of the result array.
+
+install
+=======
+
+With [npm](http://npmjs.org) do:
+
+```
+npm install concat-map
+```
+
+license
+=======
+
+MIT
+
+notes
+=====
+
+This module was written while sitting high above the ground in a tree.
diff --git a/server/node_modules/concat-map/example/map.js b/server/node_modules/concat-map/example/map.js
new file mode 100644
index 0000000..3365621
--- /dev/null
+++ b/server/node_modules/concat-map/example/map.js
@@ -0,0 +1,6 @@
+var concatMap = require('../');
+var xs = [ 1, 2, 3, 4, 5, 6 ];
+var ys = concatMap(xs, function (x) {
+    return x % 2 ? [ x - 0.1, x, x + 0.1 ] : [];
+});
+console.dir(ys);
diff --git a/server/node_modules/concat-map/index.js b/server/node_modules/concat-map/index.js
new file mode 100644
index 0000000..b29a781
--- /dev/null
+++ b/server/node_modules/concat-map/index.js
@@ -0,0 +1,13 @@
+module.exports = function (xs, fn) {
+    var res = [];
+    for (var i = 0; i < xs.length; i++) {
+        var x = fn(xs[i], i);
+        if (isArray(x)) res.push.apply(res, x);
+        else res.push(x);
+    }
+    return res;
+};
+
+var isArray = Array.isArray || function (xs) {
+    return Object.prototype.toString.call(xs) === '[object Array]';
+};
diff --git a/server/node_modules/concat-map/package.json b/server/node_modules/concat-map/package.json
new file mode 100644
index 0000000..d3640e6
--- /dev/null
+++ b/server/node_modules/concat-map/package.json
@@ -0,0 +1,43 @@
+{
+    "name" : "concat-map",
+    "description" : "concatenative mapdashery",
+    "version" : "0.0.1",
+    "repository" : {
+        "type" : "git",
+        "url" : "git://github.com/substack/node-concat-map.git"
+    },
+    "main" : "index.js",
+    "keywords" : [
+        "concat",
+        "concatMap",
+        "map",
+        "functional",
+        "higher-order"
+    ],
+    "directories" : {
+        "example" : "example",
+        "test" : "test"
+    },
+    "scripts" : {
+        "test" : "tape test/*.js"
+    },
+    "devDependencies" : {
+        "tape" : "~2.4.0"
+    },
+    "license" : "MIT",
+    "author" : {
+        "name" : "James Halliday",
+        "email" : "mail@substack.net",
+        "url" : "http://substack.net"
+    },
+    "testling" : {
+        "files" : "test/*.js",
+        "browsers" : {
+            "ie" : [ 6, 7, 8, 9 ],
+            "ff" : [ 3.5, 10, 15.0 ],
+            "chrome" : [ 10, 22 ],
+            "safari" : [ 5.1 ],
+            "opera" : [ 12 ]
+        }
+    }
+}
diff --git a/server/node_modules/concat-map/test/map.js b/server/node_modules/concat-map/test/map.js
new file mode 100644
index 0000000..fdbd702
--- /dev/null
+++ b/server/node_modules/concat-map/test/map.js
@@ -0,0 +1,39 @@
+var concatMap = require('../');
+var test = require('tape');
+
+test('empty or not', function (t) {
+    var xs = [ 1, 2, 3, 4, 5, 6 ];
+    var ixes = [];
+    var ys = concatMap(xs, function (x, ix) {
+        ixes.push(ix);
+        return x % 2 ? [ x - 0.1, x, x + 0.1 ] : [];
+    });
+    t.same(ys, [ 0.9, 1, 1.1, 2.9, 3, 3.1, 4.9, 5, 5.1 ]);
+    t.same(ixes, [ 0, 1, 2, 3, 4, 5 ]);
+    t.end();
+});
+
+test('always something', function (t) {
+    var xs = [ 'a', 'b', 'c', 'd' ];
+    var ys = concatMap(xs, function (x) {
+        return x === 'b' ? [ 'B', 'B', 'B' ] : [ x ];
+    });
+    t.same(ys, [ 'a', 'B', 'B', 'B', 'c', 'd' ]);
+    t.end();
+});
+
+test('scalars', function (t) {
+    var xs = [ 'a', 'b', 'c', 'd' ];
+    var ys = concatMap(xs, function (x) {
+        return x === 'b' ? [ 'B', 'B', 'B' ] : x;
+    });
+    t.same(ys, [ 'a', 'B', 'B', 'B', 'c', 'd' ]);
+    t.end();
+});
+
+test('undefs', function (t) {
+    var xs = [ 'a', 'b', 'c', 'd' ];
+    var ys = concatMap(xs, function () {});
+    t.same(ys, [ undefined, undefined, undefined, undefined ]);
+    t.end();
+});
diff --git a/server/node_modules/concat-stream/LICENSE b/server/node_modules/concat-stream/LICENSE
new file mode 100644
index 0000000..99c130e
--- /dev/null
+++ b/server/node_modules/concat-stream/LICENSE
@@ -0,0 +1,24 @@
+The MIT License
+
+Copyright (c) 2013 Max Ogden
+
+Permission is hereby granted, free of charge, 
+to any person obtaining a copy of this software and 
+associated documentation files (the "Software"), to 
+deal in the Software without restriction, including 
+without limitation the rights to use, copy, modify, 
+merge, publish, distribute, sublicense, and/or sell 
+copies of the Software, and to permit persons to whom 
+the Software is furnished to do so, 
+subject to the following conditions:
+
+The above copyright notice and this permission notice 
+shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR 
+ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/concat-stream/index.js b/server/node_modules/concat-stream/index.js
new file mode 100644
index 0000000..dd672a7
--- /dev/null
+++ b/server/node_modules/concat-stream/index.js
@@ -0,0 +1,144 @@
+var Writable = require('readable-stream').Writable
+var inherits = require('inherits')
+var bufferFrom = require('buffer-from')
+
+if (typeof Uint8Array === 'undefined') {
+  var U8 = require('typedarray').Uint8Array
+} else {
+  var U8 = Uint8Array
+}
+
+function ConcatStream(opts, cb) {
+  if (!(this instanceof ConcatStream)) return new ConcatStream(opts, cb)
+
+  if (typeof opts === 'function') {
+    cb = opts
+    opts = {}
+  }
+  if (!opts) opts = {}
+
+  var encoding = opts.encoding
+  var shouldInferEncoding = false
+
+  if (!encoding) {
+    shouldInferEncoding = true
+  } else {
+    encoding =  String(encoding).toLowerCase()
+    if (encoding === 'u8' || encoding === 'uint8') {
+      encoding = 'uint8array'
+    }
+  }
+
+  Writable.call(this, { objectMode: true })
+
+  this.encoding = encoding
+  this.shouldInferEncoding = shouldInferEncoding
+
+  if (cb) this.on('finish', function () { cb(this.getBody()) })
+  this.body = []
+}
+
+module.exports = ConcatStream
+inherits(ConcatStream, Writable)
+
+ConcatStream.prototype._write = function(chunk, enc, next) {
+  this.body.push(chunk)
+  next()
+}
+
+ConcatStream.prototype.inferEncoding = function (buff) {
+  var firstBuffer = buff === undefined ? this.body[0] : buff;
+  if (Buffer.isBuffer(firstBuffer)) return 'buffer'
+  if (typeof Uint8Array !== 'undefined' && firstBuffer instanceof Uint8Array) return 'uint8array'
+  if (Array.isArray(firstBuffer)) return 'array'
+  if (typeof firstBuffer === 'string') return 'string'
+  if (Object.prototype.toString.call(firstBuffer) === "[object Object]") return 'object'
+  return 'buffer'
+}
+
+ConcatStream.prototype.getBody = function () {
+  if (!this.encoding && this.body.length === 0) return []
+  if (this.shouldInferEncoding) this.encoding = this.inferEncoding()
+  if (this.encoding === 'array') return arrayConcat(this.body)
+  if (this.encoding === 'string') return stringConcat(this.body)
+  if (this.encoding === 'buffer') return bufferConcat(this.body)
+  if (this.encoding === 'uint8array') return u8Concat(this.body)
+  return this.body
+}
+
+var isArray = Array.isArray || function (arr) {
+  return Object.prototype.toString.call(arr) == '[object Array]'
+}
+
+function isArrayish (arr) {
+  return /Array\]$/.test(Object.prototype.toString.call(arr))
+}
+
+function isBufferish (p) {
+  return typeof p === 'string' || isArrayish(p) || (p && typeof p.subarray === 'function')
+}
+
+function stringConcat (parts) {
+  var strings = []
+  var needsToString = false
+  for (var i = 0; i < parts.length; i++) {
+    var p = parts[i]
+    if (typeof p === 'string') {
+      strings.push(p)
+    } else if (Buffer.isBuffer(p)) {
+      strings.push(p)
+    } else if (isBufferish(p)) {
+      strings.push(bufferFrom(p))
+    } else {
+      strings.push(bufferFrom(String(p)))
+    }
+  }
+  if (Buffer.isBuffer(parts[0])) {
+    strings = Buffer.concat(strings)
+    strings = strings.toString('utf8')
+  } else {
+    strings = strings.join('')
+  }
+  return strings
+}
+
+function bufferConcat (parts) {
+  var bufs = []
+  for (var i = 0; i < parts.length; i++) {
+    var p = parts[i]
+    if (Buffer.isBuffer(p)) {
+      bufs.push(p)
+    } else if (isBufferish(p)) {
+      bufs.push(bufferFrom(p))
+    } else {
+      bufs.push(bufferFrom(String(p)))
+    }
+  }
+  return Buffer.concat(bufs)
+}
+
+function arrayConcat (parts) {
+  var res = []
+  for (var i = 0; i < parts.length; i++) {
+    res.push.apply(res, parts[i])
+  }
+  return res
+}
+
+function u8Concat (parts) {
+  var len = 0
+  for (var i = 0; i < parts.length; i++) {
+    if (typeof parts[i] === 'string') {
+      parts[i] = bufferFrom(parts[i])
+    }
+    len += parts[i].length
+  }
+  var u8 = new U8(len)
+  for (var i = 0, offset = 0; i < parts.length; i++) {
+    var part = parts[i]
+    for (var j = 0; j < part.length; j++) {
+      u8[offset++] = part[j]
+    }
+  }
+  return u8
+}
diff --git a/server/node_modules/concat-stream/package.json b/server/node_modules/concat-stream/package.json
new file mode 100644
index 0000000..f709022
--- /dev/null
+++ b/server/node_modules/concat-stream/package.json
@@ -0,0 +1,55 @@
+{
+  "name": "concat-stream",
+  "version": "1.6.2",
+  "description": "writable stream that concatenates strings or binary data and calls a callback with the result",
+  "tags": [
+    "stream",
+    "simple",
+    "util",
+    "utility"
+  ],
+  "author": "Max Ogden <max@maxogden.com>",
+  "repository": {
+    "type": "git",
+    "url": "http://github.com/maxogden/concat-stream.git"
+  },
+  "bugs": {
+    "url": "http://github.com/maxogden/concat-stream/issues"
+  },
+  "engines": [
+    "node >= 0.8"
+  ],
+  "main": "index.js",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "test": "tape test/*.js test/server/*.js"
+  },
+  "license": "MIT",
+  "dependencies": {
+    "buffer-from": "^1.0.0",
+    "inherits": "^2.0.3",
+    "readable-stream": "^2.2.2",
+    "typedarray": "^0.0.6"
+  },
+  "devDependencies": {
+    "tape": "^4.6.3"
+  },
+  "testling": {
+    "files": "test/*.js",
+    "browsers": [
+      "ie/8..latest",
+      "firefox/17..latest",
+      "firefox/nightly",
+      "chrome/22..latest",
+      "chrome/canary",
+      "opera/12..latest",
+      "opera/next",
+      "safari/5.1..latest",
+      "ipad/6.0..latest",
+      "iphone/6.0..latest",
+      "android-browser/4.2..latest"
+    ]
+  }
+}
diff --git a/server/node_modules/concat-stream/readme.md b/server/node_modules/concat-stream/readme.md
new file mode 100644
index 0000000..7aa19c4
--- /dev/null
+++ b/server/node_modules/concat-stream/readme.md
@@ -0,0 +1,102 @@
+# concat-stream
+
+Writable stream that concatenates all the data from a stream and calls a callback with the result. Use this when you want to collect all the data from a stream into a single buffer.
+
+[![Build Status](https://travis-ci.org/maxogden/concat-stream.svg?branch=master)](https://travis-ci.org/maxogden/concat-stream)
+
+[![NPM](https://nodei.co/npm/concat-stream.png)](https://nodei.co/npm/concat-stream/)
+
+### description
+
+Streams emit many buffers. If you want to collect all of the buffers, and when the stream ends concatenate all of the buffers together and receive a single buffer then this is the module for you.
+
+Only use this if you know you can fit all of the output of your stream into a single Buffer (e.g. in RAM).
+
+There are also `objectMode` streams that emit things other than Buffers, and you can concatenate these too. See below for details.
+
+## Related
+
+`concat-stream` is part of the [mississippi stream utility collection](https://github.com/maxogden/mississippi) which includes more useful stream modules similar to this one.
+
+### examples
+
+#### Buffers
+
+```js
+var fs = require('fs')
+var concat = require('concat-stream')
+
+var readStream = fs.createReadStream('cat.png')
+var concatStream = concat(gotPicture)
+
+readStream.on('error', handleError)
+readStream.pipe(concatStream)
+
+function gotPicture(imageBuffer) {
+  // imageBuffer is all of `cat.png` as a node.js Buffer
+}
+
+function handleError(err) {
+  // handle your error appropriately here, e.g.:
+  console.error(err) // print the error to STDERR
+  process.exit(1) // exit program with non-zero exit code
+}
+
+```
+
+#### Arrays
+
+```js
+var write = concat(function(data) {})
+write.write([1,2,3])
+write.write([4,5,6])
+write.end()
+// data will be [1,2,3,4,5,6] in the above callback
+```
+
+#### Uint8Arrays
+
+```js
+var write = concat(function(data) {})
+var a = new Uint8Array(3)
+a[0] = 97; a[1] = 98; a[2] = 99
+write.write(a)
+write.write('!')
+write.end(Buffer.from('!!1'))
+```
+
+See `test/` for more examples
+
+# methods
+
+```js
+var concat = require('concat-stream')
+```
+
+## var writable = concat(opts={}, cb)
+
+Return a `writable` stream that will fire `cb(data)` with all of the data that
+was written to the stream. Data can be written to `writable` as strings,
+Buffers, arrays of byte integers, and Uint8Arrays. 
+
+By default `concat-stream` will give you back the same data type as the type of the first buffer written to the stream. Use `opts.encoding` to set what format `data` should be returned as, e.g. if you if you don't want to rely on the built-in type checking or for some other reason.
+
+* `string` - get a string
+* `buffer` - get back a Buffer
+* `array` - get an array of byte integers
+* `uint8array`, `u8`, `uint8` - get back a Uint8Array
+* `object`, get back an array of Objects
+
+If you don't specify an encoding, and the types can't be inferred (e.g. you write things that aren't in the list above), it will try to convert concat them into a `Buffer`.
+
+If nothing is written to `writable` then `data` will be an empty array `[]`.
+
+# error handling
+
+`concat-stream` does not handle errors for you, so you must handle errors on whatever streams you pipe into `concat-stream`. This is a general rule when programming with node.js streams: always handle errors on each and every stream. Since `concat-stream` is not itself a stream it does not emit errors.
+
+We recommend using [`end-of-stream`](https://npmjs.org/end-of-stream) or [`pump`](https://npmjs.org/pump) for writing error tolerant stream code.
+
+# license
+
+MIT LICENSE
diff --git a/server/node_modules/connect-sqlite3/LICENSE b/server/node_modules/connect-sqlite3/LICENSE
new file mode 100644
index 0000000..859634b
--- /dev/null
+++ b/server/node_modules/connect-sqlite3/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 David Feinberg
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/connect-sqlite3/Readme.md b/server/node_modules/connect-sqlite3/Readme.md
new file mode 100644
index 0000000..789482c
--- /dev/null
+++ b/server/node_modules/connect-sqlite3/Readme.md
@@ -0,0 +1,56 @@
+# Connect SQLite3
+
+connect-sqlite3 is a SQLite3 session store modeled after the TJ's connect-redis store.
+
+
+## Installation
+```sh
+	  $ npm install connect-sqlite3
+```
+
+## Options
+
+  - `table='sessions'` Database table name
+  - `db='sessionsDB'` Database file name (defaults to table name)
+  - `dir='.'` Directory to save '<db>.db' file
+  - `createDirIfNotExists='false'` Directory 'dir' is created recursively if not exists 
+  - `concurrentDB='false'` Enables [WAL](https://www.sqlite.org/wal.html) mode (defaults to false)
+
+## Usage
+```js
+    var connect = require('connect'),
+        SQLiteStore = require('connect-sqlite3')(connect);
+
+    connect.createServer(
+      connect.cookieParser(),
+      connect.session({ store: new SQLiteStore, secret: 'your secret' })
+    );
+```
+  with express
+```js
+    3.x:
+    var SQLiteStore = require('connect-sqlite3')(express);
+
+    4.x:
+    var session = require('express-session');
+    var SQLiteStore = require('connect-sqlite3')(session);
+
+    app.configure(function() {
+      app.set('views', __dirname + '/views');
+      app.set('view engine', 'ejs');
+      app.use(express.bodyParser());
+      app.use(express.methodOverride());
+      app.use(express.cookieParser());
+      app.use(session({
+        store: new SQLiteStore,
+        secret: 'your secret',
+        cookie: { maxAge: 7 * 24 * 60 * 60 * 1000 } // 1 week
+      }));
+      app.use(app.router);
+      app.use(express.static(__dirname + '/public'));
+    });
+```
+## Test
+```sh
+    $ npm test
+```
diff --git a/server/node_modules/connect-sqlite3/lib/connect-sqlite3.js b/server/node_modules/connect-sqlite3/lib/connect-sqlite3.js
new file mode 100644
index 0000000..9f21cb7
--- /dev/null
+++ b/server/node_modules/connect-sqlite3/lib/connect-sqlite3.js
@@ -0,0 +1,215 @@
+/**
+ * Connect - SQLite3
+ * Copyright(c) 2012 David Feinberg
+ * MIT Licensed
+ * forked from https://github.com/tnantoka/connect-sqlite
+ */
+
+/**
+ * Module dependencies.
+ */
+var sqlite3 = require('sqlite3'),
+    events = require('events'),
+    fs = require('fs');
+
+/**
+ * @type {Integer}  One day in milliseconds.
+ */
+var oneDay = 86400000;
+
+/**
+ * Return the SQLiteStore extending connect's session Store.
+ *
+ * @param   {object}    connect
+ * @return  {Function}
+ * @api     public
+ */
+module.exports = function(connect) {
+    /**
+     * Connect's Store.
+     */
+    var Store = (connect.session) ? connect.session.Store : connect.Store;
+
+    /**
+     * Remove expired sessions from database.
+     * @param   {Object}    store
+     * @api     private
+     */
+    function dbCleanup(store) {
+        var now = new Date().getTime();
+        store.db.run('DELETE FROM ' + store.table + ' WHERE ? > expired', [now]);
+    }
+
+    /**
+     * Initialize SQLiteStore with the given options.
+     *
+     * @param   {Object}    options
+     * @api     public
+     */
+    function SQLiteStore(options) {
+        options = options || {};
+        Store.call(this, options);
+
+        this.table = options.table || 'sessions';
+        this.db = options.db || this.table;
+        var dbPath;
+
+        if (this.db.indexOf(':memory:') > -1 || this.db.indexOf('?mode=memory') > -1) {
+            dbPath = this.db;
+        } else {
+            dbPath = (options.dir || '.') + '/' + this.db;
+        }
+
+        if (options.dir && options.createDirIfNotExists) {
+            try {
+                fs.mkdirSync(options.dir,
+                    {
+                        recursive: true
+                    });
+            }
+            catch {
+            }
+        }
+        
+        this.db = new sqlite3.Database(dbPath, options.mode);
+        this.client = new events.EventEmitter();
+        var self = this;
+
+        this.db.exec((options.concurrentDb ? 'PRAGMA journal_mode = wal; ' : '') + 'CREATE TABLE IF NOT EXISTS ' + this.table + ' (' + 'sid PRIMARY KEY, ' + 'expired, sess)',
+            function(err) {
+                if (err) throw err;
+                self.client.emit('connect');
+
+                dbCleanup(self);
+                setInterval(dbCleanup, oneDay, self).unref();
+            }
+        );
+    }
+
+    /**
+     * Inherit from Store.
+     */
+    SQLiteStore.prototype = Object.create(Store.prototype);
+    SQLiteStore.prototype.constructor = SQLiteStore;
+
+    /**
+     * Attempt to fetch session by the given sid.
+     *
+     * @param   {String}    sid
+     * @param   {Function}  fn
+     * @api     public
+     */
+    SQLiteStore.prototype.get = function(sid, fn) {
+        var now = new Date().getTime();
+        this.db.get('SELECT sess FROM ' + this.table + ' WHERE sid = ? AND ? <= expired', [sid, now],
+            function(err, row) {
+                if (err) fn(err);
+                if (!row) return fn();
+                fn(null, JSON.parse(row.sess));
+            }
+        );
+    };
+
+    /**
+     * Commit the given `sess` object associated with the given `sid`.
+     *
+     * @param   {String}    sid
+     * @param   {Session}   sess
+     * @param   {Function}  fn
+     * @api     public
+     */
+    SQLiteStore.prototype.set = function(sid, sess, fn) {
+        try {
+            var maxAge = sess.cookie.maxAge;
+            var now = new Date().getTime();
+            var expired = maxAge ? now + maxAge : now + oneDay;
+            sess = JSON.stringify(sess);
+
+            this.db.all('INSERT OR REPLACE INTO ' + this.table + ' VALUES (?, ?, ?)',
+                [sid, expired, sess],
+                function(err, rows) {
+                    if (fn) fn.apply(this, arguments);
+                }
+            );
+        } catch (e) {
+            if (fn) fn(e);
+        }
+    };
+
+    /**
+     * Destroy the session associated with the given `sid`.
+     *
+     * @param   {String}    sid
+     * @api     public
+     */
+    SQLiteStore.prototype.destroy = function(sid, fn) {
+        this.db.run('DELETE FROM ' + this.table + ' WHERE sid = ?', [sid], fn);
+    };
+
+    /**
+     * Fetch all sessions.
+     *
+     * @param   {Function}  fn
+     * @api     public
+     */
+    SQLiteStore.prototype.all = function(fn) {
+        this.db.all('SELECT * FROM ' + this.table + '', function(err, rows) {
+            if (err) fn(err);
+            fn(null, rows.map((row) => JSON.parse(row.sess)));
+        });
+    };
+
+    /**
+     * Fetch number of sessions.
+     *
+     * @param   {Function}  fn
+     * @api     public
+     */
+    SQLiteStore.prototype.length = function(fn) {
+        this.db.all('SELECT COUNT(*) AS count FROM ' + this.table + '', function(err, rows) {
+            if (err) fn(err);
+            fn(null, rows[0].count);
+        });
+    };
+
+    /**
+     * Clear all sessions.
+     *
+     * @param   {Function}  fn
+     * @api     public
+     */
+    SQLiteStore.prototype.clear = function(fn) {
+        this.db.exec('DELETE FROM ' + this.table + '', function(err) {
+            if (err) fn(err);
+            fn(null, true);
+        });
+    };
+
+    /**
+     * Touch the given session object associated with the given session ID.
+     *
+     * @param   {string}    sid
+     * @param   {object}    session
+     * @param   {function}  fn
+     * @public
+     */
+    SQLiteStore.prototype.touch = function(sid, session, fn) {
+        if (session && session.cookie && session.cookie.expires) {
+            var now = new Date().getTime();
+            var cookieExpires = new Date(session.cookie.expires).getTime();
+            this.db.run('UPDATE ' + this.table + ' SET expired=? WHERE sid = ? AND ? <= expired',
+                [cookieExpires, sid, now],
+                function(err) {
+                    if (fn) {
+                        if (err) fn(err);
+                        fn(null, true);
+                    }
+                }
+            );
+        } else {
+           fn(null, true);
+        }
+    }
+
+    return SQLiteStore;
+};
diff --git a/server/node_modules/connect-sqlite3/package.json b/server/node_modules/connect-sqlite3/package.json
new file mode 100644
index 0000000..d865ef1
--- /dev/null
+++ b/server/node_modules/connect-sqlite3/package.json
@@ -0,0 +1,31 @@
+{
+  "name": "connect-sqlite3",
+  "description": "SQLite3 session store for Connect",
+  "version": "0.9.16",
+  "author": "David Feinberg",
+  "main": "lib/connect-sqlite3",
+  "scripts": {
+    "test": "mocha test/test.js"
+  },
+  "dependencies": {
+    "sqlite3": "^5.0.2"
+  },
+  "devDependencies": {
+    "connect": ">=1.0.0",
+    "express-session": "^1.13.0",
+    "mocha": "^2.3.4",
+    "should": "^8.2.0"
+  },
+  "engines": {
+    "node": ">=0.4.x"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/rawberg/connect-sqlite3.git"
+  },
+  "licenses": [
+    {
+      "type": "MIT"
+    }
+  ]
+}
diff --git a/server/node_modules/connect-sqlite3/test/mocha.css b/server/node_modules/connect-sqlite3/test/mocha.css
new file mode 100644
index 0000000..cdfea1a
--- /dev/null
+++ b/server/node_modules/connect-sqlite3/test/mocha.css
@@ -0,0 +1,182 @@
+
+body {
+  font: 20px/1.5 "Helvetica Neue", Helvetica, Arial, sans-serif;
+  padding: 60px 50px;
+}
+
+#mocha ul, #mocha li {
+  margin: 0;
+  padding: 0;
+}
+
+#mocha ul {
+  list-style: none;
+}
+
+#mocha h1, #mocha h2 {
+  margin: 0;
+}
+
+#mocha h1 {
+  margin-top: 15px;
+  font-size: 1em;
+  font-weight: 200;
+}
+
+#mocha h1 a {
+  text-decoration: none;
+  color: inherit;
+}
+
+#mocha h1 a:hover {
+  text-decoration: underline;
+}
+
+#mocha .suite .suite h1 {
+  margin-top: 0;
+  font-size: .8em;
+}
+
+#mocha h2 {
+  font-size: 12px;
+  font-weight: normal;
+  cursor: pointer;
+}
+
+#mocha .suite {
+  margin-left: 15px;
+}
+
+#mocha .test {
+  margin-left: 15px;
+}
+
+#mocha .test:hover h2::after {
+  position: relative;
+  top: 0;
+  right: -10px;
+  content: '(view source)';
+  font-size: 12px;
+  font-family: arial;
+  color: #888;
+}
+
+#mocha .test.pending:hover h2::after {
+  content: '(pending)';
+  font-family: arial;
+}
+
+#mocha .test.pass.medium .duration {
+  background: #C09853;
+}
+
+#mocha .test.pass.slow .duration {
+  background: #B94A48;
+}
+
+#mocha .test.pass::before {
+  content: '✓';
+  font-size: 12px;
+  display: block;
+  float: left;
+  margin-right: 5px;
+  color: #00d6b2;
+}
+
+#mocha .test.pass .duration {
+  font-size: 9px;
+  margin-left: 5px;
+  padding: 2px 5px;
+  color: white;
+  -webkit-box-shadow: inset 0 1px 1px rgba(0,0,0,.2);
+  -moz-box-shadow: inset 0 1px 1px rgba(0,0,0,.2);
+  box-shadow: inset 0 1px 1px rgba(0,0,0,.2);
+  -webkit-border-radius: 5px;
+  -moz-border-radius: 5px;
+  -ms-border-radius: 5px;
+  -o-border-radius: 5px;
+  border-radius: 5px;
+}
+
+#mocha .test.pass.fast .duration {
+  display: none;
+}
+
+#mocha .test.pending {
+  color: #0b97c4;
+}
+
+#mocha .test.pending::before {
+  content: '◦';
+  color: #0b97c4;
+}
+
+#mocha .test.fail {
+  color: #c00;
+}
+
+#mocha .test.fail pre {
+  color: black;
+}
+
+#mocha .test.fail::before {
+  content: '✖';
+  font-size: 12px;
+  display: block;
+  float: left;
+  margin-right: 5px;
+  color: #c00;
+}
+
+#mocha .test pre.error {
+  color: #c00;
+}
+
+#mocha .test pre {
+  display: inline-block;
+  font: 12px/1.5 monaco, monospace;
+  margin: 5px;
+  padding: 15px;
+  border: 1px solid #eee;
+  border-bottom-color: #ddd;
+  -webkit-border-radius: 3px;
+  -webkit-box-shadow: 0 1px 3px #eee;
+}
+
+#error {
+  color: #c00;
+  font-size: 1.5  em;
+  font-weight: 100;
+  letter-spacing: 1px;
+}
+
+#stats {
+  position: fixed;
+  top: 15px;
+  right: 10px;
+  font-size: 12px;
+  margin: 0;
+  color: #888;
+}
+
+#stats .progress {
+  float: right;
+  padding-top: 0;
+}
+
+#stats em {
+  color: black;
+}
+
+#stats li {
+  display: inline-block;
+  margin: 0 5px;
+  list-style: none;
+  padding-top: 11px;
+}
+
+code .comment { color: #ddd }
+code .init { color: #2F6FAD }
+code .string { color: #5890AD }
+code .keyword { color: #8A6343 }
+code .number { color: #2F6FAD }
diff --git a/server/node_modules/connect-sqlite3/test/mocha.js b/server/node_modules/connect-sqlite3/test/mocha.js
new file mode 100644
index 0000000..3487337
--- /dev/null
+++ b/server/node_modules/connect-sqlite3/test/mocha.js
@@ -0,0 +1,4504 @@
+;(function(){
+
+
+// CommonJS require()
+
+function require(p){
+    var path = require.resolve(p)
+      , mod = require.modules[path];
+    if (!mod) throw new Error('failed to require "' + p + '"');
+    if (!mod.exports) {
+      mod.exports = {};
+      mod.call(mod.exports, mod, mod.exports, require.relative(path));
+    }
+    return mod.exports;
+  }
+
+require.modules = {};
+
+require.resolve = function (path){
+    var orig = path
+      , reg = path + '.js'
+      , index = path + '/index.js';
+    return require.modules[reg] && reg
+      || require.modules[index] && index
+      || orig;
+  };
+
+require.register = function (path, fn){
+    require.modules[path] = fn;
+  };
+
+require.relative = function (parent) {
+    return function(p){
+      if ('.' != p.charAt(0)) return require(p);
+      
+      var path = parent.split('/')
+        , segs = p.split('/');
+      path.pop();
+      
+      for (var i = 0; i < segs.length; i++) {
+        var seg = segs[i];
+        if ('..' == seg) path.pop();
+        else if ('.' != seg) path.push(seg);
+      }
+
+      return require(path.join('/'));
+    };
+  };
+
+
+require.register("browser/debug.js", function(module, exports, require){
+
+module.exports = function(type){
+  return function(){
+    
+  }
+};
+}); // module: browser/debug.js
+
+require.register("browser/diff.js", function(module, exports, require){
+
+}); // module: browser/diff.js
+
+require.register("browser/events.js", function(module, exports, require){
+
+/**
+ * Module exports.
+ */
+
+exports.EventEmitter = EventEmitter;
+
+/**
+ * Check if `obj` is an array.
+ */
+
+function isArray(obj) {
+  return '[object Array]' == {}.toString.call(obj);
+}
+
+/**
+ * Event emitter constructor.
+ *
+ * @api public
+ */
+
+function EventEmitter(){};
+
+/**
+ * Adds a listener.
+ *
+ * @api public
+ */
+
+EventEmitter.prototype.on = function (name, fn) {
+  if (!this.$events) {
+    this.$events = {};
+  }
+
+  if (!this.$events[name]) {
+    this.$events[name] = fn;
+  } else if (isArray(this.$events[name])) {
+    this.$events[name].push(fn);
+  } else {
+    this.$events[name] = [this.$events[name], fn];
+  }
+
+  return this;
+};
+
+EventEmitter.prototype.addListener = EventEmitter.prototype.on;
+
+/**
+ * Adds a volatile listener.
+ *
+ * @api public
+ */
+
+EventEmitter.prototype.once = function (name, fn) {
+  var self = this;
+
+  function on () {
+    self.removeListener(name, on);
+    fn.apply(this, arguments);
+  };
+
+  on.listener = fn;
+  this.on(name, on);
+
+  return this;
+};
+
+/**
+ * Removes a listener.
+ *
+ * @api public
+ */
+
+EventEmitter.prototype.removeListener = function (name, fn) {
+  if (this.$events && this.$events[name]) {
+    var list = this.$events[name];
+
+    if (isArray(list)) {
+      var pos = -1;
+
+      for (var i = 0, l = list.length; i < l; i++) {
+        if (list[i] === fn || (list[i].listener && list[i].listener === fn)) {
+          pos = i;
+          break;
+        }
+      }
+
+      if (pos < 0) {
+        return this;
+      }
+
+      list.splice(pos, 1);
+
+      if (!list.length) {
+        delete this.$events[name];
+      }
+    } else if (list === fn || (list.listener && list.listener === fn)) {
+      delete this.$events[name];
+    }
+  }
+
+  return this;
+};
+
+/**
+ * Removes all listeners for an event.
+ *
+ * @api public
+ */
+
+EventEmitter.prototype.removeAllListeners = function (name) {
+  if (name === undefined) {
+    this.$events = {};
+    return this;
+  }
+
+  if (this.$events && this.$events[name]) {
+    this.$events[name] = null;
+  }
+
+  return this;
+};
+
+/**
+ * Gets all listeners for a certain event.
+ *
+ * @api public
+ */
+
+EventEmitter.prototype.listeners = function (name) {
+  if (!this.$events) {
+    this.$events = {};
+  }
+
+  if (!this.$events[name]) {
+    this.$events[name] = [];
+  }
+
+  if (!isArray(this.$events[name])) {
+    this.$events[name] = [this.$events[name]];
+  }
+
+  return this.$events[name];
+};
+
+/**
+ * Emits an event.
+ *
+ * @api public
+ */
+
+EventEmitter.prototype.emit = function (name) {
+  if (!this.$events) {
+    return false;
+  }
+
+  var handler = this.$events[name];
+
+  if (!handler) {
+    return false;
+  }
+
+  var args = [].slice.call(arguments, 1);
+
+  if ('function' == typeof handler) {
+    handler.apply(this, args);
+  } else if (isArray(handler)) {
+    var listeners = handler.slice();
+
+    for (var i = 0, l = listeners.length; i < l; i++) {
+      listeners[i].apply(this, args);
+    }
+  } else {
+    return false;
+  }
+
+  return true;
+};
+}); // module: browser/events.js
+
+require.register("browser/fs.js", function(module, exports, require){
+
+}); // module: browser/fs.js
+
+require.register("browser/path.js", function(module, exports, require){
+
+}); // module: browser/path.js
+
+require.register("browser/progress.js", function(module, exports, require){
+
+/**
+ * Expose `Progress`.
+ */
+
+module.exports = Progress;
+
+/**
+ * Initialize a new `Progress` indicator.
+ */
+
+function Progress() {
+  this.percent = 0;
+  this.size(0);
+  this.fontSize(11);
+  this.font('helvetica, arial, sans-serif');
+}
+
+/**
+ * Set progress size to `n`.
+ *
+ * @param {Number} n
+ * @return {Progress} for chaining
+ * @api public
+ */
+
+Progress.prototype.size = function(n){
+  this._size = n;
+  return this;
+};
+
+/**
+ * Set text to `str`.
+ *
+ * @param {String} str
+ * @return {Progress} for chaining
+ * @api public
+ */
+
+Progress.prototype.text = function(str){
+  this._text = str;
+  return this;
+};
+
+/**
+ * Set font size to `n`.
+ *
+ * @param {Number} n
+ * @return {Progress} for chaining
+ * @api public
+ */
+
+Progress.prototype.fontSize = function(n){
+  this._fontSize = n;
+  return this;
+};
+
+/**
+ * Set font `family`.
+ *
+ * @param {String} family
+ * @return {Progress} for chaining
+ */
+
+Progress.prototype.font = function(family){
+  this._font = family;
+  return this;
+};
+
+/**
+ * Update percentage to `n`.
+ *
+ * @param {Number} n
+ * @return {Progress} for chaining
+ */
+
+Progress.prototype.update = function(n){
+  this.percent = n;
+  return this;
+};
+
+/**
+ * Draw on `ctx`.
+ *
+ * @param {CanvasRenderingContext2d} ctx
+ * @return {Progress} for chaining
+ */
+
+Progress.prototype.draw = function(ctx){
+  var percent = Math.min(this.percent, 100)
+    , size = this._size
+    , half = size / 2
+    , x = half
+    , y = half
+    , rad = half - 1
+    , fontSize = this._fontSize;
+
+  ctx.font = fontSize + 'px ' + this._font;
+
+  var angle = Math.PI * 2 * (percent / 100);
+  ctx.clearRect(0, 0, size, size);
+
+  // outer circle
+  ctx.strokeStyle = '#9f9f9f';
+  ctx.beginPath();
+  ctx.arc(x, y, rad, 0, angle, false);
+  ctx.stroke();
+
+  // inner circle
+  ctx.strokeStyle = '#eee';
+  ctx.beginPath();
+  ctx.arc(x, y, rad - 1, 0, angle, true);
+  ctx.stroke();
+
+  // text
+  var text = this._text || (percent | 0) + '%'
+    , w = ctx.measureText(text).width;
+
+  ctx.fillText(
+      text
+    , x - w / 2 + 1
+    , y + fontSize / 2 - 1);
+
+  return this;
+};
+
+}); // module: browser/progress.js
+
+require.register("browser/tty.js", function(module, exports, require){
+
+exports.isatty = function(){
+  return true;
+};
+
+exports.getWindowSize = function(){
+  return [window.innerHeight, window.innerWidth];
+};
+}); // module: browser/tty.js
+
+require.register("context.js", function(module, exports, require){
+
+/**
+ * Expose `Context`.
+ */
+
+module.exports = Context;
+
+/**
+ * Initialize a new `Context`.
+ *
+ * @api private
+ */
+
+function Context(){}
+
+/**
+ * Set or get the context `Runnable` to `runnable`.
+ *
+ * @param {Runnable} runnable
+ * @return {Context}
+ * @api private
+ */
+
+Context.prototype.runnable = function(runnable){
+  if (0 == arguments.length) return this._runnable;
+  this.test = this._runnable = runnable;
+  return this;
+};
+
+/**
+ * Set test timeout `ms`.
+ *
+ * @param {Number} ms
+ * @return {Context} self
+ * @api private
+ */
+
+Context.prototype.timeout = function(ms){
+  this.runnable().timeout(ms);
+  return this;
+};
+
+/**
+ * Inspect the context void of `._runnable`.
+ *
+ * @return {String}
+ * @api private
+ */
+
+Context.prototype.inspect = function(){
+  return JSON.stringify(this, function(key, val){
+    if ('_runnable' == key) return;
+    if ('test' == key) return;
+    return val;
+  }, 2);
+};
+
+}); // module: context.js
+
+require.register("hook.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Runnable = require('./runnable');
+
+/**
+ * Expose `Hook`.
+ */
+
+module.exports = Hook;
+
+/**
+ * Initialize a new `Hook` with the given `title` and callback `fn`.
+ *
+ * @param {String} title
+ * @param {Function} fn
+ * @api private
+ */
+
+function Hook(title, fn) {
+  Runnable.call(this, title, fn);
+  this.type = 'hook';
+}
+
+/**
+ * Inherit from `Runnable.prototype`.
+ */
+
+Hook.prototype = new Runnable;
+Hook.prototype.constructor = Hook;
+
+
+/**
+ * Get or set the test `err`.
+ *
+ * @param {Error} err
+ * @return {Error}
+ * @api public
+ */
+
+Hook.prototype.error = function(err){
+  if (0 == arguments.length) {
+    var err = this._error;
+    this._error = null;
+    return err;
+  }
+
+  this._error = err;
+};
+
+
+}); // module: hook.js
+
+require.register("interfaces/bdd.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Suite = require('../suite')
+  , Test = require('../test');
+
+/**
+ * BDD-style interface:
+ * 
+ *      describe('Array', function(){
+ *        describe('#indexOf()', function(){
+ *          it('should return -1 when not present', function(){
+ *
+ *          });
+ *
+ *          it('should return the index when present', function(){
+ *
+ *          });
+ *        });
+ *      });
+ * 
+ */
+
+module.exports = function(suite){
+  var suites = [suite];
+
+  suite.on('pre-require', function(context){
+
+    // noop variants
+
+    context.xdescribe = function(){};
+    context.xit = function(){};
+
+    /**
+     * Execute before running tests.
+     */
+
+    context.before = function(fn){
+      suites[0].beforeAll(fn);
+    };
+
+    /**
+     * Execute after running tests.
+     */
+
+    context.after = function(fn){
+      suites[0].afterAll(fn);
+    };
+
+    /**
+     * Execute before each test case.
+     */
+
+    context.beforeEach = function(fn){
+      suites[0].beforeEach(fn);
+    };
+
+    /**
+     * Execute after each test case.
+     */
+
+    context.afterEach = function(fn){
+      suites[0].afterEach(fn);
+    };
+
+    /**
+     * Describe a "suite" with the given `title`
+     * and callback `fn` containing nested suites
+     * and/or tests.
+     */
+  
+    context.describe = context.context = function(title, fn){
+      var suite = Suite.create(suites[0], title);
+      suites.unshift(suite);
+      fn();
+      suites.shift();
+    };
+
+    /**
+     * Describe a specification or test-case
+     * with the given `title` and callback `fn`
+     * acting as a thunk.
+     */
+
+    context.it = context.specify = function(title, fn){
+      suites[0].addTest(new Test(title, fn));
+    };
+  });
+};
+
+}); // module: interfaces/bdd.js
+
+require.register("interfaces/exports.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Suite = require('../suite')
+  , Test = require('../test');
+
+/**
+ * TDD-style interface:
+ * 
+ *     exports.Array = {
+ *       '#indexOf()': {
+ *         'should return -1 when the value is not present': function(){
+ *           
+ *         },
+ *
+ *         'should return the correct index when the value is present': function(){
+ *           
+ *         }
+ *       }
+ *     };
+ * 
+ */
+
+module.exports = function(suite){
+  var suites = [suite];
+
+  suite.on('require', visit);
+
+  function visit(obj) {
+    var suite;
+    for (var key in obj) {
+      if ('function' == typeof obj[key]) {
+        var fn = obj[key];
+        switch (key) {
+          case 'before':
+            suites[0].beforeAll(fn);
+            break;
+          case 'after':
+            suites[0].afterAll(fn);
+            break;
+          case 'beforeEach':
+            suites[0].beforeEach(fn);
+            break;
+          case 'afterEach':
+            suites[0].afterEach(fn);
+            break;
+          default:
+            suites[0].addTest(new Test(key, fn));
+        }
+      } else {
+        var suite = Suite.create(suites[0], key);
+        suites.unshift(suite);
+        visit(obj[key]);
+        suites.shift();
+      }
+    }
+  }
+};
+}); // module: interfaces/exports.js
+
+require.register("interfaces/index.js", function(module, exports, require){
+
+exports.bdd = require('./bdd');
+exports.tdd = require('./tdd');
+exports.qunit = require('./qunit');
+exports.exports = require('./exports');
+
+}); // module: interfaces/index.js
+
+require.register("interfaces/qunit.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Suite = require('../suite')
+  , Test = require('../test');
+
+/**
+ * QUnit-style interface:
+ * 
+ *     suite('Array');
+ *     
+ *     test('#length', function(){
+ *       var arr = [1,2,3];
+ *       ok(arr.length == 3);
+ *     });
+ *     
+ *     test('#indexOf()', function(){
+ *       var arr = [1,2,3];
+ *       ok(arr.indexOf(1) == 0);
+ *       ok(arr.indexOf(2) == 1);
+ *       ok(arr.indexOf(3) == 2);
+ *     });
+ *     
+ *     suite('String');
+ *     
+ *     test('#length', function(){
+ *       ok('foo'.length == 3);
+ *     });
+ * 
+ */
+
+module.exports = function(suite){
+  var suites = [suite];
+
+  suite.on('pre-require', function(context){
+
+    /**
+     * Execute before running tests.
+     */
+
+    context.before = function(fn){
+      suites[0].beforeAll(fn);
+    };
+
+    /**
+     * Execute after running tests.
+     */
+
+    context.after = function(fn){
+      suites[0].afterAll(fn);
+    };
+
+    /**
+     * Execute before each test case.
+     */
+
+    context.beforeEach = function(fn){
+      suites[0].beforeEach(fn);
+    };
+
+    /**
+     * Execute after each test case.
+     */
+
+    context.afterEach = function(fn){
+      suites[0].afterEach(fn);
+    };
+
+    /**
+     * Describe a "suite" with the given `title`.
+     */
+  
+    context.suite = function(title){
+      if (suites.length > 1) suites.shift();
+      var suite = Suite.create(suites[0], title);
+      suites.unshift(suite);
+    };
+
+    /**
+     * Describe a specification or test-case
+     * with the given `title` and callback `fn`
+     * acting as a thunk.
+     */
+
+    context.test = function(title, fn){
+      suites[0].addTest(new Test(title, fn));
+    };
+  });
+};
+
+}); // module: interfaces/qunit.js
+
+require.register("interfaces/tdd.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Suite = require('../suite')
+  , Test = require('../test');
+
+/**
+ * TDD-style interface:
+ *
+ *      suite('Array', function(){
+ *        suite('#indexOf()', function(){
+ *          suiteSetup(function(){
+ *
+ *          });
+ *          
+ *          test('should return -1 when not present', function(){
+ *
+ *          });
+ *
+ *          test('should return the index when present', function(){
+ *
+ *          });
+ *
+ *          suiteTeardown(function(){
+ *
+ *          });
+ *        });
+ *      });
+ *
+ */
+
+module.exports = function(suite){
+  var suites = [suite];
+
+  suite.on('pre-require', function(context){
+
+    /**
+     * Execute before each test case.
+     */
+
+    context.setup = function(fn){
+      suites[0].beforeEach(fn);
+    };
+
+    /**
+     * Execute after each test case.
+     */
+
+    context.teardown = function(fn){
+      suites[0].afterEach(fn);
+    };
+
+    /**
+     * Execute before the suite.
+     */
+
+    context.suiteSetup = function(fn){
+      suites[0].beforeAll(fn);
+    };
+
+    /**
+     * Execute after the suite.
+     */
+
+    context.suiteTeardown = function(fn){
+      suites[0].afterAll(fn);
+    };
+
+    /**
+     * Describe a "suite" with the given `title`
+     * and callback `fn` containing nested suites
+     * and/or tests.
+     */
+
+    context.suite = function(title, fn){
+      var suite = Suite.create(suites[0], title);
+      suites.unshift(suite);
+      fn();
+      suites.shift();
+    };
+
+    /**
+     * Describe a specification or test-case
+     * with the given `title` and callback `fn`
+     * acting as a thunk.
+     */
+
+    context.test = function(title, fn){
+      suites[0].addTest(new Test(title, fn));
+    };
+  });
+};
+
+}); // module: interfaces/tdd.js
+
+require.register("mocha.js", function(module, exports, require){
+/*!
+ * mocha
+ * Copyright(c) 2011 TJ Holowaychuk <tj@vision-media.ca>
+ * MIT Licensed
+ */
+
+/**
+ * Module dependencies.
+ */
+
+var path = require('browser/path');
+
+/**
+ * Expose `Mocha`.
+ */
+
+exports = module.exports = Mocha;
+
+/**
+ * Expose internals.
+ */
+
+exports.utils = require('./utils');
+exports.interfaces = require('./interfaces');
+exports.reporters = require('./reporters');
+exports.Runnable = require('./runnable');
+exports.Context = require('./context');
+exports.Runner = require('./runner');
+exports.Suite = require('./suite');
+exports.Hook = require('./hook');
+exports.Test = require('./test');
+
+/**
+ * Return image `name` path.
+ *
+ * @param {String} name
+ * @return {String}
+ * @api private
+ */
+
+function image(name) {
+  return __dirname + '/../images/' + name + '.png';
+}
+
+/**
+ * Setup mocha with `options`.
+ *
+ * Options:
+ *
+ *   - `ui` name "bdd", "tdd", "exports" etc
+ *   - `reporter` reporter instance, defaults to `mocha.reporters.Dot`
+ *   - `globals` array of accepted globals
+ *   - `timeout` timeout in milliseconds
+ *   - `ignoreLeaks` ignore global leaks
+ *   - `grep` string or regexp to filter tests with
+ *
+ * @param {Object} options
+ * @api public
+ */
+
+function Mocha(options) {
+  options = options || {};
+  this.files = [];
+  this.options = options;
+  this.grep(options.grep);
+  this.suite = new exports.Suite('', new exports.Context);
+  this.ui(options.ui);
+  this.reporter(options.reporter);
+  if (options.timeout) this.suite.timeout(options.timeout);
+}
+
+/**
+ * Add test `file`.
+ *
+ * @param {String} file
+ * @api public
+ */
+
+Mocha.prototype.addFile = function(file){
+  this.files.push(file);
+  return this;
+};
+
+/**
+ * Set reporter to `name`, defaults to "dot".
+ *
+ * @param {String} name
+ * @api public
+ */
+
+Mocha.prototype.reporter = function(name){
+  name = name || 'dot';
+  this._reporter = require('./reporters/' + name);
+  if (!this._reporter) throw new Error('invalid reporter "' + name + '"');
+  return this;
+};
+
+/**
+ * Set test UI `name`, defaults to "bdd".
+ *
+ * @param {String} bdd
+ * @api public
+ */
+
+Mocha.prototype.ui = function(name){
+  name = name || 'bdd';
+  this._ui = exports.interfaces[name];
+  if (!this._ui) throw new Error('invalid interface "' + name + '"');
+  this._ui = this._ui(this.suite);
+  return this;
+};
+
+/**
+ * Load registered files.
+ *
+ * @api private
+ */
+
+Mocha.prototype.loadFiles = function(){
+  var suite = this.suite;
+  this.files.forEach(function(file){
+    file = path.resolve(file);
+    suite.emit('pre-require', global, file);
+    suite.emit('require', require(file), file);
+    suite.emit('post-require', global, file);
+  });
+};
+
+/**
+ * Enable growl support.
+ *
+ * @api private
+ */
+
+Mocha.prototype.growl = function(runner, reporter) {
+  var notify = require('growl');
+
+  runner.on('end', function(){
+    var stats = reporter.stats;
+    if (stats.failures) {
+      var msg = stats.failures + ' of ' + runner.total + ' tests failed';
+      notify(msg, { name: 'mocha', title: 'Failed', image: image('error') });
+    } else {
+      notify(stats.passes + ' tests passed in ' + stats.duration + 'ms', {
+          name: 'mocha'
+        , title: 'Passed'
+        , image: image('ok')
+      });
+    }
+  });
+};
+
+/**
+ * Add regexp to grep for to the options object
+ *
+ * @param {RegExp} or {String} re
+ * @return {Mocha}
+ * @api public
+ */
+
+Mocha.prototype.grep = function(re){
+  this.options.grep = 'string' == typeof re
+    ? new RegExp(re)
+    : re;
+  return this;
+};
+
+/**
+ * Run tests and invoke `fn()` when complete.
+ *
+ * @param {Function} fn
+ * @return {Runner}
+ * @api public
+ */
+
+Mocha.prototype.run = function(fn){
+  this.loadFiles();
+  var suite = this.suite;
+  var options = this.options;
+  var runner = new exports.Runner(suite);
+  var reporter = new this._reporter(runner);
+  runner.ignoreLeaks = options.ignoreLeaks;
+  if (options.grep) runner.grep(options.grep);
+  if (options.globals) runner.globals(options.globals);
+  if (options.growl) this.growl(runner, reporter);
+  return runner.run(fn);
+};
+
+}); // module: mocha.js
+
+require.register("reporters/base.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var tty = require('browser/tty')
+  , diff = require('browser/diff');
+
+/**
+ * Save timer references to avoid Sinon interfering (see GH-237).
+ */
+
+var Date = global.Date
+  , setTimeout = global.setTimeout
+  , setInterval = global.setInterval
+  , clearTimeout = global.clearTimeout
+  , clearInterval = global.clearInterval;
+
+/**
+ * Check if both stdio streams are associated with a tty.
+ */
+
+var isatty = tty.isatty(1) && tty.isatty(2);
+
+/**
+ * Expose `Base`.
+ */
+
+exports = module.exports = Base;
+
+/**
+ * Enable coloring by default.
+ */
+
+exports.useColors = isatty;
+
+/**
+ * Default color map.
+ */
+
+exports.colors = {
+    'pass': 90
+  , 'fail': 31
+  , 'bright pass': 92
+  , 'bright fail': 91
+  , 'bright yellow': 93
+  , 'pending': 36
+  , 'suite': 0
+  , 'error title': 0
+  , 'error message': 31
+  , 'error stack': 90
+  , 'checkmark': 32
+  , 'fast': 90
+  , 'medium': 33
+  , 'slow': 31
+  , 'green': 32
+  , 'light': 90
+  , 'diff gutter': 90
+  , 'diff added': 42
+  , 'diff removed': 41
+};
+
+/**
+ * Color `str` with the given `type`,
+ * allowing colors to be disabled,
+ * as well as user-defined color
+ * schemes.
+ *
+ * @param {String} type
+ * @param {String} str
+ * @return {String}
+ * @api private
+ */
+
+var color = exports.color = function(type, str) {
+  if (!exports.useColors) return str;
+  return '\033[' + exports.colors[type] + 'm' + str + '\033[0m';
+};
+
+/**
+ * Expose term window size, with some
+ * defaults for when stderr is not a tty.
+ */
+
+exports.window = {
+  width: isatty
+    ? process.stdout.getWindowSize
+      ? process.stdout.getWindowSize(1)[0]
+      : tty.getWindowSize()[1]
+    : 75
+};
+
+/**
+ * Expose some basic cursor interactions
+ * that are common among reporters.
+ */
+
+exports.cursor = {
+  hide: function(){
+    process.stdout.write('\033[?25l');
+  },
+
+  show: function(){
+    process.stdout.write('\033[?25h');
+  },
+
+  deleteLine: function(){
+    process.stdout.write('\033[2K');
+  },
+
+  beginningOfLine: function(){
+    process.stdout.write('\033[0G');
+  },
+
+  CR: function(){
+    exports.cursor.deleteLine();
+    exports.cursor.beginningOfLine();
+  }
+};
+
+/**
+ * A test is considered slow if it
+ * exceeds the following value in milliseconds.
+ */
+
+exports.slow = 75;
+
+/**
+ * Outut the given `failures` as a list.
+ *
+ * @param {Array} failures
+ * @api public
+ */
+
+exports.list = function(failures){
+  console.error();
+  failures.forEach(function(test, i){
+    // format
+    var fmt = color('error title', '  %s) %s:\n')
+      + color('error message', '     %s')
+      + color('error stack', '\n%s\n');
+
+    // msg
+    var err = test.err
+      , message = err.message || ''
+      , stack = err.stack || message
+      , index = stack.indexOf(message) + message.length
+      , msg = stack.slice(0, index)
+      , actual = err.actual
+      , expected = err.expected;
+
+    // actual / expected diff
+    if ('string' == typeof actual && 'string' == typeof expected) {
+      var len = Math.max(actual.length, expected.length);
+
+      if (len < 20) msg = errorDiff(err, 'Chars');
+      else msg = errorDiff(err, 'Words');
+
+      // linenos
+      var lines = msg.split('\n');
+      if (lines.length > 4) {
+        var width = String(lines.length).length;
+        msg = lines.map(function(str, i){
+          return pad(++i, width) + ' |' + ' ' + str;
+        }).join('\n');
+      }
+
+      // legend
+      msg = '\n'
+        + color('diff removed', 'actual')
+        + ' '
+        + color('diff added', 'expected')
+        + '\n\n'
+        + msg
+        + '\n';
+
+      // indent
+      msg = msg.replace(/^/gm, '      ');
+
+      fmt = color('error title', '  %s) %s:\n%s')
+        + color('error stack', '\n%s\n');
+    }
+
+    // indent stack trace without msg
+    stack = stack.slice(index ? index + 1 : index)
+      .replace(/^/gm, '  ');
+
+    console.error(fmt, (i + 1), test.fullTitle(), msg, stack);
+  });
+};
+
+/**
+ * Initialize a new `Base` reporter.
+ *
+ * All other reporters generally
+ * inherit from this reporter, providing
+ * stats such as test duration, number
+ * of tests passed / failed etc.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function Base(runner) {
+  var self = this
+    , stats = this.stats = { suites: 0, tests: 0, passes: 0, pending: 0, failures: 0 }
+    , failures = this.failures = [];
+
+  if (!runner) return;
+  this.runner = runner;
+
+  runner.on('start', function(){
+    stats.start = new Date;
+  });
+
+  runner.on('suite', function(suite){
+    stats.suites = stats.suites || 0;
+    suite.root || stats.suites++;
+  });
+
+  runner.on('test end', function(test){
+    stats.tests = stats.tests || 0;
+    stats.tests++;
+  });
+
+  runner.on('pass', function(test){
+    stats.passes = stats.passes || 0;
+
+    var medium = exports.slow / 2;
+    test.speed = test.duration > exports.slow
+      ? 'slow'
+      : test.duration > medium
+        ? 'medium'
+        : 'fast';
+
+    stats.passes++;
+  });
+
+  runner.on('fail', function(test, err){
+    stats.failures = stats.failures || 0;
+    stats.failures++;
+    test.err = err;
+    failures.push(test);
+  });
+
+  runner.on('end', function(){
+    stats.end = new Date;
+    stats.duration = new Date - stats.start;
+  });
+
+  runner.on('pending', function(){
+    stats.pending++;
+  });
+}
+
+/**
+ * Output common epilogue used by many of
+ * the bundled reporters.
+ *
+ * @api public
+ */
+
+Base.prototype.epilogue = function(){
+  var stats = this.stats
+    , fmt
+    , tests;
+
+  console.log();
+
+  function pluralize(n) {
+    return 1 == n ? 'test' : 'tests';
+  }
+
+  // failure
+  if (stats.failures) {
+    fmt = color('bright fail', '  ✖')
+      + color('fail', ' %d of %d %s failed')
+      + color('light', ':')
+
+    console.error(fmt,
+      stats.failures,
+      this.runner.total,
+      pluralize(this.runner.total));
+
+    Base.list(this.failures);
+    console.error();
+    return;
+  }
+
+  // pass
+  fmt = color('bright pass', '  ✔')
+    + color('green', ' %d %s complete')
+    + color('light', ' (%dms)');
+
+  console.log(fmt,
+    stats.tests || 0,
+    pluralize(stats.tests),
+    stats.duration);
+
+  // pending
+  if (stats.pending) {
+    fmt = color('pending', '  •')
+      + color('pending', ' %d %s pending');
+
+    console.log(fmt, stats.pending, pluralize(stats.pending));
+  }
+
+  console.log();
+};
+
+/**
+ * Pad the given `str` to `len`.
+ *
+ * @param {String} str
+ * @param {String} len
+ * @return {String}
+ * @api private
+ */
+
+function pad(str, len) {
+  str = String(str);
+  return Array(len - str.length + 1).join(' ') + str;
+}
+
+/**
+ * Return a character diff for `err`.
+ *
+ * @param {Error} err
+ * @return {String}
+ * @api private
+ */
+
+function errorDiff(err, type) {
+  return diff['diff' + type](err.actual, err.expected).map(function(str){
+    if (/^(\n+)$/.test(str.value)) str.value = Array(++RegExp.$1.length).join('<newline>');
+    if (str.added) return colorLines('diff added', str.value);
+    if (str.removed) return colorLines('diff removed', str.value);
+    return str.value;
+  }).join('');
+}
+
+/**
+ * Color lines for `str`, using the color `name`.
+ *
+ * @param {String} name
+ * @param {String} str
+ * @return {String}
+ * @api private
+ */
+
+function colorLines(name, str) {
+  return str.split('\n').map(function(str){
+    return color(name, str);
+  }).join('\n');
+}
+
+}); // module: reporters/base.js
+
+require.register("reporters/doc.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , utils = require('../utils');
+
+/**
+ * Expose `Doc`.
+ */
+
+exports = module.exports = Doc;
+
+/**
+ * Initialize a new `Doc` reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function Doc(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , total = runner.total
+    , indents = 2;
+
+  function indent() {
+    return Array(indents).join('  ');
+  }
+
+  runner.on('suite', function(suite){
+    if (suite.root) return;
+    ++indents;
+    console.log('%s<section class="suite">', indent());
+    ++indents;
+    console.log('%s<h1>%s</h1>', indent(), suite.title);
+    console.log('%s<dl>', indent());
+  });
+
+  runner.on('suite end', function(suite){
+    if (suite.root) return;
+    console.log('%s</dl>', indent());
+    --indents;
+    console.log('%s</section>', indent());
+    --indents;
+  });
+
+  runner.on('pass', function(test){
+    console.log('%s  <dt>%s</dt>', indent(), test.title);
+    var code = utils.escape(utils.clean(test.fn.toString()));
+    console.log('%s  <dd><pre><code>%s</code></pre></dd>', indent(), code);
+  });
+}
+
+}); // module: reporters/doc.js
+
+require.register("reporters/dot.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , color = Base.color;
+
+/**
+ * Expose `Dot`.
+ */
+
+exports = module.exports = Dot;
+
+/**
+ * Initialize a new `Dot` matrix test reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function Dot(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , width = Base.window.width * .75 | 0
+    , n = 0;
+
+  runner.on('start', function(){
+    process.stdout.write('\n  ');
+  });
+
+  runner.on('pending', function(test){
+    process.stdout.write(color('pending', '.'));
+  });
+
+  runner.on('pass', function(test){
+    if (++n % width == 0) process.stdout.write('\n  ');
+    if ('slow' == test.speed) {
+      process.stdout.write(color('bright yellow', '.'));
+    } else {
+      process.stdout.write(color(test.speed, '.'));
+    }
+  });
+
+  runner.on('fail', function(test, err){
+    if (++n % width == 0) process.stdout.write('\n  ');
+    process.stdout.write(color('fail', '.'));
+  });
+
+  runner.on('end', function(){
+    console.log();
+    self.epilogue();
+  });
+}
+
+/**
+ * Inherit from `Base.prototype`.
+ */
+
+Dot.prototype = new Base;
+Dot.prototype.constructor = Dot;
+
+}); // module: reporters/dot.js
+
+require.register("reporters/html-cov.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var JSONCov = require('./json-cov')
+  , fs = require('browser/fs');
+
+/**
+ * Expose `HTMLCov`.
+ */
+
+exports = module.exports = HTMLCov;
+
+/**
+ * Initialize a new `JsCoverage` reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function HTMLCov(runner) {
+  var jade = require('jade')
+    , file = __dirname + '/templates/coverage.jade'
+    , str = fs.readFileSync(file, 'utf8')
+    , fn = jade.compile(str, { filename: file })
+    , self = this;
+
+  JSONCov.call(this, runner, false);
+
+  runner.on('end', function(){
+    process.stdout.write(fn({
+        cov: self.cov
+      , coverageClass: coverageClass
+    }));
+  });
+}
+
+/**
+ * Return coverage class for `n`.
+ *
+ * @return {String}
+ * @api private
+ */
+
+function coverageClass(n) {
+  if (n >= 75) return 'high';
+  if (n >= 50) return 'medium';
+  if (n >= 25) return 'low';
+  return 'terrible';
+}
+}); // module: reporters/html-cov.js
+
+require.register("reporters/html.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , utils = require('../utils')
+  , Progress = require('../browser/progress')
+  , escape = utils.escape;
+
+/**
+ * Save timer references to avoid Sinon interfering (see GH-237).
+ */
+
+var Date = global.Date
+  , setTimeout = global.setTimeout
+  , setInterval = global.setInterval
+  , clearTimeout = global.clearTimeout
+  , clearInterval = global.clearInterval;
+
+/**
+ * Expose `Doc`.
+ */
+
+exports = module.exports = HTML;
+
+/**
+ * Stats template.
+ */
+
+var statsTemplate = '<ul id="stats">'
+  + '<li class="progress"><canvas width="40" height="40"></canvas></li>'
+  + '<li class="passes">passes: <em>0</em></li>'
+  + '<li class="failures">failures: <em>0</em></li>'
+  + '<li class="duration">duration: <em>0</em>s</li>'
+  + '</ul>';
+
+/**
+ * Initialize a new `Doc` reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function HTML(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , total = runner.total
+    , root = document.getElementById('mocha')
+    , stat = fragment(statsTemplate)
+    , items = stat.getElementsByTagName('li')
+    , passes = items[1].getElementsByTagName('em')[0]
+    , failures = items[2].getElementsByTagName('em')[0]
+    , duration = items[3].getElementsByTagName('em')[0]
+    , canvas = stat.getElementsByTagName('canvas')[0]
+    , report = fragment('<ul id="report"></ul>')
+    , stack = [report]
+    , progress
+    , ctx
+
+  if (canvas.getContext) {
+    ctx = canvas.getContext('2d');
+    progress = new Progress;
+  }
+
+  if (!root) return error('#mocha div missing, add it to your document');
+
+  root.appendChild(stat);
+  root.appendChild(report);
+
+  if (progress) progress.size(40);
+
+  runner.on('suite', function(suite){
+    if (suite.root) return;
+
+    // suite
+    var url = location.protocol + '//' + location.host + location.pathname + '?grep=^' + utils.escapeRegexp(suite.fullTitle());
+    var el = fragment('<li class="suite"><h1><a href="%s">%s</a></h1></li>', url, escape(suite.title));
+
+    // container
+    stack[0].appendChild(el);
+    stack.unshift(document.createElement('ul'));
+    el.appendChild(stack[0]);
+  });
+
+  runner.on('suite end', function(suite){
+    if (suite.root) return;
+    stack.shift();
+  });
+
+  runner.on('fail', function(test, err){
+    if ('hook' == test.type || err.uncaught) runner.emit('test end', test);
+  });
+
+  runner.on('test end', function(test){
+    window.scrollTo(0, document.body.scrollHeight);
+
+    // TODO: add to stats
+    var percent = stats.tests / total * 100 | 0;
+    if (progress) progress.update(percent).draw(ctx);
+
+    // update stats
+    var ms = new Date - stats.start;
+    text(passes, stats.passes);
+    text(failures, stats.failures);
+    text(duration, (ms / 1000).toFixed(2));
+
+    // test
+    if ('passed' == test.state) {
+      var el = fragment('<li class="test pass %e"><h2>%e<span class="duration">%ems</span></h2></li>', test.speed, test.title, test.duration);
+    } else if (test.pending) {
+      var el = fragment('<li class="test pass pending"><h2>%e</h2></li>', test.title);
+    } else {
+      var el = fragment('<li class="test fail"><h2>%e</h2></li>', test.title);
+      var str = test.err.stack || test.err.toString();
+
+      // FF / Opera do not add the message
+      if (!~str.indexOf(test.err.message)) {
+        str = test.err.message + '\n' + str;
+      }
+
+      // <=IE7 stringifies to [Object Error]. Since it can be overloaded, we
+      // check for the result of the stringifying.
+      if ('[object Error]' == str) str = test.err.message;
+
+      // Safari doesn't give you a stack. Let's at least provide a source line.
+      if (!test.err.stack && test.err.sourceURL && test.err.line !== undefined) {
+        str += "\n(" + test.err.sourceURL + ":" + test.err.line + ")";
+      }
+
+      el.appendChild(fragment('<pre class="error">%e</pre>', str));
+    }
+
+    // toggle code
+    var h2 = el.getElementsByTagName('h2')[0];
+
+    on(h2, 'click', function(){
+      pre.style.display = 'none' == pre.style.display
+        ? 'block'
+        : 'none';
+    });
+
+    // code
+    // TODO: defer
+    if (!test.pending) {
+      var pre = fragment('<pre><code>%e</code></pre>', utils.clean(test.fn.toString()));
+      el.appendChild(pre);
+      pre.style.display = 'none';
+    }
+
+    stack[0].appendChild(el);
+  });
+}
+
+/**
+ * Display error `msg`.
+ */
+
+function error(msg) {
+  document.body.appendChild(fragment('<div id="error">%s</div>', msg));
+}
+
+/**
+ * Return a DOM fragment from `html`.
+ */
+
+function fragment(html) {
+  var args = arguments
+    , div = document.createElement('div')
+    , i = 1;
+
+  div.innerHTML = html.replace(/%([se])/g, function(_, type){
+    switch (type) {
+      case 's': return String(args[i++]);
+      case 'e': return escape(args[i++]);
+    }
+  });
+
+  return div.firstChild;
+}
+
+/**
+ * Set `el` text to `str`.
+ */
+
+function text(el, str) {
+  if (el.textContent) {
+    el.textContent = str;
+  } else {
+    el.innerText = str;
+  }
+}
+
+/**
+ * Listen on `event` with callback `fn`.
+ */
+
+function on(el, event, fn) {
+  if (el.addEventListener) {
+    el.addEventListener(event, fn, false);
+  } else {
+    el.attachEvent('on' + event, fn);
+  }
+}
+}); // module: reporters/html.js
+
+require.register("reporters/index.js", function(module, exports, require){
+
+exports.Base = require('./base');
+exports.Dot = require('./dot');
+exports.Doc = require('./doc');
+exports.TAP = require('./tap');
+exports.JSON = require('./json');
+exports.HTML = require('./html');
+exports.List = require('./list');
+exports.Min = require('./min');
+exports.Spec = require('./spec');
+exports.Nyan = require('./nyan');
+exports.XUnit = require('./xunit');
+exports.Progress = require('./progress');
+exports.Landing = require('./landing');
+exports.JSONCov = require('./json-cov');
+exports.HTMLCov = require('./html-cov');
+exports.JSONStream = require('./json-stream');
+exports.Teamcity = require('./teamcity');
+
+}); // module: reporters/index.js
+
+require.register("reporters/json-cov.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base');
+
+/**
+ * Expose `JSONCov`.
+ */
+
+exports = module.exports = JSONCov;
+
+/**
+ * Initialize a new `JsCoverage` reporter.
+ *
+ * @param {Runner} runner
+ * @param {Boolean} output
+ * @api public
+ */
+
+function JSONCov(runner, output) {
+  var self = this
+    , output = 1 == arguments.length ? true : output;
+
+  Base.call(this, runner);
+
+  var tests = []
+    , failures = []
+    , passes = [];
+
+  runner.on('test end', function(test){
+    tests.push(test);
+  });
+
+  runner.on('pass', function(test){
+    passes.push(test);
+  });
+
+  runner.on('fail', function(test){
+    failures.push(test);
+  });
+
+  runner.on('end', function(){
+    var cov = global._$jscoverage || {};
+    var result = self.cov = map(cov);
+    result.stats = self.stats;
+    result.tests = tests.map(clean);
+    result.failures = failures.map(clean);
+    result.passes = passes.map(clean);
+    if (!output) return;
+    process.stdout.write(JSON.stringify(result, null, 2 ));
+  });
+}
+
+/**
+ * Map jscoverage data to a JSON structure
+ * suitable for reporting.
+ *
+ * @param {Object} cov
+ * @return {Object}
+ * @api private
+ */
+
+function map(cov) {
+  var ret = {
+      instrumentation: 'node-jscoverage'
+    , sloc: 0
+    , hits: 0
+    , misses: 0
+    , coverage: 0
+    , files: []
+  };
+
+  for (var filename in cov) {
+    var data = coverage(filename, cov[filename]);
+    ret.files.push(data);
+    ret.hits += data.hits;
+    ret.misses += data.misses;
+    ret.sloc += data.sloc;
+  }
+
+  if (ret.sloc > 0) {
+    ret.coverage = (ret.hits / ret.sloc) * 100;
+  }
+
+  return ret;
+};
+
+/**
+ * Map jscoverage data for a single source file
+ * to a JSON structure suitable for reporting.
+ *
+ * @param {String} filename name of the source file
+ * @param {Object} data jscoverage coverage data
+ * @return {Object}
+ * @api private
+ */
+
+function coverage(filename, data) {
+  var ret = {
+    filename: filename,
+    coverage: 0,
+    hits: 0,
+    misses: 0,
+    sloc: 0,
+    source: {}
+  };
+
+  data.source.forEach(function(line, num){
+    num++;
+
+    if (data[num] === 0) {
+      ret.misses++;
+      ret.sloc++;
+    } else if (data[num] !== undefined) {
+      ret.hits++;
+      ret.sloc++;
+    }
+
+    ret.source[num] = {
+        source: line
+      , coverage: data[num] === undefined
+        ? ''
+        : data[num]
+    };
+  });
+
+  ret.coverage = ret.hits / ret.sloc * 100;
+
+  return ret;
+}
+
+/**
+ * Return a plain-object representation of `test`
+ * free of cyclic properties etc.
+ *
+ * @param {Object} test
+ * @return {Object}
+ * @api private
+ */
+
+function clean(test) {
+  return {
+      title: test.title
+    , fullTitle: test.fullTitle()
+    , duration: test.duration
+  }
+}
+
+}); // module: reporters/json-cov.js
+
+require.register("reporters/json-stream.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , color = Base.color;
+
+/**
+ * Expose `List`.
+ */
+
+exports = module.exports = List;
+
+/**
+ * Initialize a new `List` test reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function List(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , total = runner.total;
+
+  runner.on('start', function(){
+    console.log(JSON.stringify(['start', { total: total }]));
+  });
+
+  runner.on('pass', function(test){
+    console.log(JSON.stringify(['pass', clean(test)]));
+  });
+
+  runner.on('fail', function(test, err){
+    console.log(JSON.stringify(['fail', clean(test)]));
+  });
+
+  runner.on('end', function(){
+    process.stdout.write(JSON.stringify(['end', self.stats]));
+  });
+}
+
+/**
+ * Return a plain-object representation of `test`
+ * free of cyclic properties etc.
+ *
+ * @param {Object} test
+ * @return {Object}
+ * @api private
+ */
+
+function clean(test) {
+  return {
+      title: test.title
+    , fullTitle: test.fullTitle()
+    , duration: test.duration
+  }
+}
+}); // module: reporters/json-stream.js
+
+require.register("reporters/json.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , cursor = Base.cursor
+  , color = Base.color;
+
+/**
+ * Expose `JSON`.
+ */
+
+exports = module.exports = JSONReporter;
+
+/**
+ * Initialize a new `JSON` reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function JSONReporter(runner) {
+  var self = this;
+  Base.call(this, runner);
+
+  var tests = []
+    , failures = []
+    , passes = [];
+
+  runner.on('test end', function(test){
+    tests.push(test);
+  });
+
+  runner.on('pass', function(test){
+    passes.push(test);
+  });
+
+  runner.on('fail', function(test){
+    failures.push(test);
+  });
+
+  runner.on('end', function(){
+    var obj = {
+        stats: self.stats
+      , tests: tests.map(clean)
+      , failures: failures.map(clean)
+      , passes: passes.map(clean)
+    };
+
+    process.stdout.write(JSON.stringify(obj, null, 2));
+  });
+}
+
+/**
+ * Return a plain-object representation of `test`
+ * free of cyclic properties etc.
+ *
+ * @param {Object} test
+ * @return {Object}
+ * @api private
+ */
+
+function clean(test) {
+  return {
+      title: test.title
+    , fullTitle: test.fullTitle()
+    , duration: test.duration
+  }
+}
+}); // module: reporters/json.js
+
+require.register("reporters/landing.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , cursor = Base.cursor
+  , color = Base.color;
+
+/**
+ * Expose `Landing`.
+ */
+
+exports = module.exports = Landing;
+
+/**
+ * Airplane color.
+ */
+
+Base.colors.plane = 0;
+
+/**
+ * Airplane crash color.
+ */
+
+Base.colors['plane crash'] = 31;
+
+/**
+ * Runway color.
+ */
+
+Base.colors.runway = 90;
+
+/**
+ * Initialize a new `Landing` reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function Landing(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , width = Base.window.width * .75 | 0
+    , total = runner.total
+    , stream = process.stdout
+    , plane = color('plane', '✈')
+    , crashed = -1
+    , n = 0;
+
+  function runway() {
+    var buf = Array(width).join('-');
+    return '  ' + color('runway', buf);
+  }
+
+  runner.on('start', function(){
+    stream.write('\n  ');
+    cursor.hide();
+  });
+
+  runner.on('test end', function(test){
+    // check if the plane crashed
+    var col = -1 == crashed
+      ? width * ++n / total | 0
+      : crashed;
+
+    // show the crash
+    if ('failed' == test.state) {
+      plane = color('plane crash', '✈');
+      crashed = col;
+    }
+
+    // render landing strip
+    stream.write('\033[4F\n\n');
+    stream.write(runway());
+    stream.write('\n  ');
+    stream.write(color('runway', Array(col).join('⋅')));
+    stream.write(plane)
+    stream.write(color('runway', Array(width - col).join('⋅') + '\n'));
+    stream.write(runway());
+    stream.write('\033[0m');
+  });
+
+  runner.on('end', function(){
+    cursor.show();
+    console.log();
+    self.epilogue();
+  });
+}
+
+/**
+ * Inherit from `Base.prototype`.
+ */
+
+Landing.prototype = new Base;
+Landing.prototype.constructor = Landing;
+
+}); // module: reporters/landing.js
+
+require.register("reporters/list.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , cursor = Base.cursor
+  , color = Base.color;
+
+/**
+ * Expose `List`.
+ */
+
+exports = module.exports = List;
+
+/**
+ * Initialize a new `List` test reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function List(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , n = 0;
+
+  runner.on('start', function(){
+    console.log();
+  });
+
+  runner.on('test', function(test){
+    process.stdout.write(color('pass', '    ' + test.fullTitle() + ': '));
+  });
+
+  runner.on('pending', function(test){
+    var fmt = color('checkmark', '  -')
+      + color('pending', ' %s');
+    console.log(fmt, test.fullTitle());
+  });
+
+  runner.on('pass', function(test){
+    var fmt = color('checkmark', '  ✓')
+      + color('pass', ' %s: ')
+      + color(test.speed, '%dms');
+    cursor.CR();
+    console.log(fmt, test.fullTitle(), test.duration);
+  });
+
+  runner.on('fail', function(test, err){
+    cursor.CR();
+    console.log(color('fail', '  %d) %s'), ++n, test.fullTitle());
+  });
+
+  runner.on('end', self.epilogue.bind(self));
+}
+
+/**
+ * Inherit from `Base.prototype`.
+ */
+
+List.prototype = new Base;
+List.prototype.constructor = List;
+
+
+}); // module: reporters/list.js
+
+require.register("reporters/markdown.js", function(module, exports, require){
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , utils = require('../utils');
+
+/**
+ * Expose `Markdown`.
+ */
+
+exports = module.exports = Markdown;
+
+/**
+ * Initialize a new `Markdown` reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function Markdown(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , total = runner.total
+    , level = 0
+    , buf = '';
+
+  function title(str) {
+    return Array(level).join('#') + ' ' + str;
+  }
+
+  function indent() {
+    return Array(level).join('  ');
+  }
+
+  function mapTOC(suite, obj) {
+    var ret = obj;
+    obj = obj[suite.title] = obj[suite.title] || { suite: suite };
+    suite.suites.forEach(function(suite){
+      mapTOC(suite, obj);
+    });
+    return ret;
+  }
+
+  function stringifyTOC(obj, level) {
+    ++level;
+    var buf = '';
+    var link;
+    for (var key in obj) {
+      if ('suite' == key) continue;
+      if (key) link = ' - [' + key + '](#' + utils.slug(obj[key].suite.fullTitle()) + ')\n';
+      if (key) buf += Array(level).join('  ') + link;
+      buf += stringifyTOC(obj[key], level);
+    }
+    --level;
+    return buf;
+  }
+
+  function generateTOC(suite) {
+    var obj = mapTOC(suite, {});
+    return stringifyTOC(obj, 0);
+  }
+
+  generateTOC(runner.suite);
+
+  runner.on('suite', function(suite){
+    ++level;
+    var slug = utils.slug(suite.fullTitle());
+    buf += '<a name="' + slug + '" />' + '\n';
+    buf += title(suite.title) + '\n';
+  });
+
+  runner.on('suite end', function(suite){
+    --level;
+  });
+
+  runner.on('pass', function(test){
+    var code = utils.clean(test.fn.toString());
+    buf += test.title + '.\n';
+    buf += '\n```js\n';
+    buf += code + '\n';
+    buf += '```\n\n';
+  });
+
+  runner.on('end', function(){
+    process.stdout.write('# TOC\n');
+    process.stdout.write(generateTOC(runner.suite));
+    process.stdout.write(buf);
+  });
+}
+}); // module: reporters/markdown.js
+
+require.register("reporters/min.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base');
+
+/**
+ * Expose `Min`.
+ */
+
+exports = module.exports = Min;
+
+/**
+ * Initialize a new `Min` minimal test reporter (best used with --watch).
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function Min(runner) {
+  Base.call(this, runner);
+  
+  runner.on('start', function(){
+    // clear screen
+    process.stdout.write('\033[2J');
+    // set cursor position
+    process.stdout.write('\033[1;3H');
+  });
+
+  runner.on('end', this.epilogue.bind(this));
+}
+
+/**
+ * Inherit from `Base.prototype`.
+ */
+
+Min.prototype = new Base;
+Min.prototype.constructor = Min;
+
+}); // module: reporters/min.js
+
+require.register("reporters/nyan.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , color = Base.color;
+
+/**
+ * Expose `Dot`.
+ */
+
+exports = module.exports = NyanCat;
+
+/**
+ * Initialize a new `Dot` matrix test reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function NyanCat(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , width = Base.window.width * .75 | 0
+    , rainbowColors = this.rainbowColors = self.generateColors()
+    , colorIndex = this.colorIndex = 0
+    , numerOfLines = this.numberOfLines = 4
+    , trajectories = this.trajectories = [[], [], [], []]
+    , nyanCatWidth = this.nyanCatWidth = 11
+    , trajectoryWidthMax = this.trajectoryWidthMax = (width - nyanCatWidth)
+    , scoreboardWidth = this.scoreboardWidth = 5
+    , tick = this.tick = 0
+    , n = 0;
+
+  runner.on('start', function(){
+    Base.cursor.hide();
+    self.draw('start');
+  });
+
+  runner.on('pending', function(test){
+    self.draw('pending');
+  });
+
+  runner.on('pass', function(test){
+    self.draw('pass');
+  });
+
+  runner.on('fail', function(test, err){
+    self.draw('fail');
+  });
+
+  runner.on('end', function(){
+    Base.cursor.show();
+    for (var i = 0; i < self.numberOfLines; i++) write('\n');
+    self.epilogue();
+  });
+}
+
+/**
+ * Draw the nyan cat with runner `status`.
+ *
+ * @param {String} status
+ * @api private
+ */
+
+NyanCat.prototype.draw = function(status){
+  this.appendRainbow();
+  this.drawScoreboard();
+  this.drawRainbow();
+  this.drawNyanCat(status);
+  this.tick = !this.tick;
+};
+
+/**
+ * Draw the "scoreboard" showing the number
+ * of passes, failures and pending tests.
+ *
+ * @api private
+ */
+
+NyanCat.prototype.drawScoreboard = function(){
+  var stats = this.stats;
+  var colors = Base.colors;
+
+  function draw(color, n) {
+    write(' ');
+    write('\033[' + color + 'm' + n + '\033[0m');
+    write('\n');
+  }
+
+  draw(colors.green, stats.passes);
+  draw(colors.fail, stats.failures);
+  draw(colors.pending, stats.pending);
+  write('\n');
+
+  this.cursorUp(this.numberOfLines);
+};
+
+/**
+ * Append the rainbow.
+ *
+ * @api private
+ */
+
+NyanCat.prototype.appendRainbow = function(){
+  var segment = this.tick ? '_' : '-';
+  var rainbowified = this.rainbowify(segment);
+
+  for (var index = 0; index < this.numberOfLines; index++) {
+    var trajectory = this.trajectories[index];
+    if (trajectory.length >= this.trajectoryWidthMax) trajectory.shift();
+    trajectory.push(rainbowified);
+  }
+};
+
+/**
+ * Draw the rainbow.
+ *
+ * @api private
+ */
+
+NyanCat.prototype.drawRainbow = function(){
+  var self = this;
+
+  this.trajectories.forEach(function(line, index) {
+    write('\033[' + self.scoreboardWidth + 'C');
+    write(line.join(''));
+    write('\n');
+  });
+
+  this.cursorUp(this.numberOfLines);
+};
+
+/**
+ * Draw the nyan cat with `status`.
+ *
+ * @param {String} status
+ * @api private
+ */
+
+NyanCat.prototype.drawNyanCat = function(status) {
+  var self = this;
+  var startWidth = this.scoreboardWidth + this.trajectories[0].length;
+
+  [0, 1, 2, 3].forEach(function(index) {
+    write('\033[' + startWidth + 'C');
+
+    switch (index) {
+      case 0:
+        write('_,------,');
+        write('\n');
+        break;
+      case 1:
+        var padding = self.tick ? '  ' : '   ';
+        write('_|' + padding + '/\\_/\\ ');
+        write('\n');
+        break;
+      case 2:
+        var padding = self.tick ? '_' : '__';
+        var tail = self.tick ? '~' : '^';
+        var face;
+        switch (status) {
+          case 'pass':
+            face = '( ^ .^)';
+            break;
+          case 'fail':
+            face = '( o .o)';
+            break;
+          default:
+            face = '( - .-)';
+        }
+        write(tail + '|' + padding + face + ' ');
+        write('\n');
+        break;
+      case 3:
+        var padding = self.tick ? ' ' : '  ';
+        write(padding + '""  "" ');
+        write('\n');
+        break;
+    }
+  });
+
+  this.cursorUp(this.numberOfLines);
+};
+
+/**
+ * Move cursor up `n`.
+ *
+ * @param {Number} n
+ * @api private
+ */
+
+NyanCat.prototype.cursorUp = function(n) {
+  write('\033[' + n + 'A');
+};
+
+/**
+ * Move cursor down `n`.
+ *
+ * @param {Number} n
+ * @api private
+ */
+
+NyanCat.prototype.cursorDown = function(n) {
+  write('\033[' + n + 'B');
+};
+
+/**
+ * Generate rainbow colors.
+ *
+ * @return {Array}
+ * @api private
+ */
+
+NyanCat.prototype.generateColors = function(){
+  var colors = [];
+
+  for (var i = 0; i < (6 * 7); i++) {
+    var pi3 = Math.floor(Math.PI / 3);
+    var n = (i * (1.0 / 6));
+    var r = Math.floor(3 * Math.sin(n) + 3);
+    var g = Math.floor(3 * Math.sin(n + 2 * pi3) + 3);
+    var b = Math.floor(3 * Math.sin(n + 4 * pi3) + 3);
+    colors.push(36 * r + 6 * g + b + 16);
+  }
+
+  return colors;
+};
+
+/**
+ * Apply rainbow to the given `str`.
+ *
+ * @param {String} str
+ * @return {String}
+ * @api private
+ */
+
+NyanCat.prototype.rainbowify = function(str){
+  var color = this.rainbowColors[this.colorIndex % this.rainbowColors.length];
+  this.colorIndex += 1;
+  return '\033[38;5;' + color + 'm' + str + '\033[0m';
+};
+
+/**
+ * Stdout helper.
+ */
+
+function write(string) {
+  process.stdout.write(string);
+}
+
+/**
+ * Inherit from `Base.prototype`.
+ */
+
+NyanCat.prototype = new Base;
+NyanCat.prototype.constructor = NyanCat;
+
+
+}); // module: reporters/nyan.js
+
+require.register("reporters/progress.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , cursor = Base.cursor
+  , color = Base.color;
+
+/**
+ * Expose `Progress`.
+ */
+
+exports = module.exports = Progress;
+
+/**
+ * General progress bar color.
+ */
+
+Base.colors.progress = 90;
+
+/**
+ * Initialize a new `Progress` bar test reporter.
+ *
+ * @param {Runner} runner
+ * @param {Object} options
+ * @api public
+ */
+
+function Progress(runner, options) {
+  Base.call(this, runner);
+
+  var self = this
+    , options = options || {}
+    , stats = this.stats
+    , width = Base.window.width * .50 | 0
+    , total = runner.total
+    , complete = 0
+    , max = Math.max;
+
+  // default chars
+  options.open = options.open || '[';
+  options.complete = options.complete || '▬';
+  options.incomplete = options.incomplete || '⋅';
+  options.close = options.close || ']';
+  options.verbose = false;
+
+  // tests started
+  runner.on('start', function(){
+    console.log();
+    cursor.hide();
+  });
+
+  // tests complete
+  runner.on('test end', function(){
+    complete++;
+    var incomplete = total - complete
+      , percent = complete / total
+      , n = width * percent | 0
+      , i = width - n;
+
+    cursor.CR();
+    process.stdout.write('\033[J');
+    process.stdout.write(color('progress', '  ' + options.open));
+    process.stdout.write(Array(n).join(options.complete));
+    process.stdout.write(Array(i).join(options.incomplete));
+    process.stdout.write(color('progress', options.close));
+    if (options.verbose) {
+      process.stdout.write(color('progress', ' ' + complete + ' of ' + total));
+    }
+  });
+
+  // tests are complete, output some stats
+  // and the failures if any
+  runner.on('end', function(){
+    cursor.show();
+    console.log();
+    self.epilogue();
+  });
+}
+
+/**
+ * Inherit from `Base.prototype`.
+ */
+
+Progress.prototype = new Base;
+Progress.prototype.constructor = Progress;
+
+
+}); // module: reporters/progress.js
+
+require.register("reporters/spec.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , cursor = Base.cursor
+  , color = Base.color;
+
+/**
+ * Expose `Spec`.
+ */
+
+exports = module.exports = Spec;
+
+/**
+ * Initialize a new `Spec` test reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function Spec(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , indents = 0
+    , n = 0;
+
+  function indent() {
+    return Array(indents).join('  ')
+  }
+
+  runner.on('start', function(){
+    console.log();
+  });
+
+  runner.on('suite', function(suite){
+    ++indents;
+    console.log(color('suite', '%s%s'), indent(), suite.title);
+  });
+
+  runner.on('suite end', function(suite){
+    --indents;
+    if (1 == indents) console.log();
+  });
+
+  runner.on('test', function(test){
+    process.stdout.write(indent() + color('pass', '  ◦ ' + test.title + ': '));
+  });
+
+  runner.on('pending', function(test){
+    var fmt = indent() + color('pending', '  - %s');
+    console.log(fmt, test.title);
+  });
+
+  runner.on('pass', function(test){
+    if ('fast' == test.speed) {
+      var fmt = indent()
+        + color('checkmark', '  ✓')
+        + color('pass', ' %s ');
+      cursor.CR();
+      console.log(fmt, test.title);
+    } else {
+      var fmt = indent()
+        + color('checkmark', '  ✓')
+        + color('pass', ' %s ')
+        + color(test.speed, '(%dms)');
+      cursor.CR();
+      console.log(fmt, test.title, test.duration);
+    }
+  });
+
+  runner.on('fail', function(test, err){
+    cursor.CR();
+    console.log(indent() + color('fail', '  %d) %s'), ++n, test.title);
+  });
+
+  runner.on('end', self.epilogue.bind(self));
+}
+
+/**
+ * Inherit from `Base.prototype`.
+ */
+
+Spec.prototype = new Base;
+Spec.prototype.constructor = Spec;
+
+
+}); // module: reporters/spec.js
+
+require.register("reporters/tap.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , cursor = Base.cursor
+  , color = Base.color;
+
+/**
+ * Expose `TAP`.
+ */
+
+exports = module.exports = TAP;
+
+/**
+ * Initialize a new `TAP` reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function TAP(runner) {
+  Base.call(this, runner);
+
+  var self = this
+    , stats = this.stats
+    , total = runner.total
+    , n = 1;
+
+  runner.on('start', function(){
+    console.log('%d..%d', 1, total);
+  });
+
+  runner.on('test end', function(){
+    ++n;
+  });
+
+  runner.on('pending', function(test){
+    console.log('ok %d %s # SKIP -', n, title(test));
+  });
+
+  runner.on('pass', function(test){
+    console.log('ok %d %s', n, title(test));
+  });
+
+  runner.on('fail', function(test, err){
+    console.log('not ok %d %s', n, title(test));
+    console.log(err.stack.replace(/^/gm, '  '));
+  });
+}
+
+/**
+ * Return a TAP-safe title of `test`
+ *
+ * @param {Object} test
+ * @return {String}
+ * @api private
+ */
+
+function title(test) {
+  return test.fullTitle().replace(/#/g, '');
+}
+
+}); // module: reporters/tap.js
+
+require.register("reporters/teamcity.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base');
+
+/**
+ * Expose `Teamcity`.
+ */
+
+exports = module.exports = Teamcity;
+
+/**
+ * Initialize a new `Teamcity` reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function Teamcity(runner) {
+  Base.call(this, runner);
+  var stats = this.stats;
+
+  runner.on('start', function() {
+    console.log("##teamcity[testSuiteStarted name='mocha.suite']");
+  });
+
+  runner.on('test', function(test) {
+    console.log("##teamcity[testStarted name='" + escape(test.fullTitle()) + "']");
+  });
+
+  runner.on('fail', function(test, err) {
+    console.log("##teamcity[testFailed name='" + escape(test.fullTitle()) + "' message='" + escape(err.message) + "']");
+  });
+
+  runner.on('pending', function(test) {
+    console.log("##teamcity[testIgnored name='" + escape(test.fullTitle()) + "' message='pending']");
+  });
+
+  runner.on('test end', function(test) {
+    console.log("##teamcity[testFinished name='" + escape(test.fullTitle()) + "' duration='" + test.duration + "']");
+  });
+
+  runner.on('end', function() {
+    console.log("##teamcity[testSuiteFinished name='mocha.suite' duration='" + stats.duration + "']");
+  });
+}
+
+/**
+ * Escape the given `str`.
+ */
+
+function escape(str) {
+  return str
+    .replace(/\|/g, "||")
+    .replace(/\n/g, "|n")
+    .replace(/\r/g, "|r")
+    .replace(/\[/g, "|[")
+    .replace(/\]/g, "|]")
+    .replace(/\u0085/g, "|x")
+    .replace(/\u2028/g, "|l")
+    .replace(/\u2029/g, "|p")
+    .replace(/'/g, "|'");
+}
+
+}); // module: reporters/teamcity.js
+
+require.register("reporters/xunit.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Base = require('./base')
+  , utils = require('../utils')
+  , escape = utils.escape;
+
+/**
+ * Save timer references to avoid Sinon interfering (see GH-237).
+ */
+
+var Date = global.Date
+  , setTimeout = global.setTimeout
+  , setInterval = global.setInterval
+  , clearTimeout = global.clearTimeout
+  , clearInterval = global.clearInterval;
+
+/**
+ * Expose `XUnit`.
+ */
+
+exports = module.exports = XUnit;
+
+/**
+ * Initialize a new `XUnit` reporter.
+ *
+ * @param {Runner} runner
+ * @api public
+ */
+
+function XUnit(runner) {
+  Base.call(this, runner);
+  var stats = this.stats
+    , tests = []
+    , self = this;
+
+  runner.on('test end', function(test){
+    tests.push(test);
+  });
+
+  runner.on('end', function(){
+    console.log(tag('testsuite', {
+        name: 'Mocha Tests'
+      , tests: stats.tests
+      , failures: stats.failures
+      , errors: stats.failures
+      , skip: stats.tests - stats.failures - stats.passes
+      , timestamp: (new Date).toUTCString()
+      , time: stats.duration / 1000
+    }, false));
+
+    tests.forEach(test);
+    console.log('</testsuite>');    
+  });
+}
+
+/**
+ * Inherit from `Base.prototype`.
+ */
+
+XUnit.prototype = new Base;
+XUnit.prototype.constructor = XUnit;
+
+
+/**
+ * Output tag for the given `test.`
+ */
+
+function test(test) {
+  var attrs = {
+      classname: test.parent.fullTitle()
+    , name: test.title
+    , time: test.duration / 1000
+  };
+
+  if ('failed' == test.state) {
+    var err = test.err;
+    attrs.message = escape(err.message);
+    console.log(tag('testcase', attrs, false, tag('failure', attrs, false, cdata(err.stack))));
+  } else if (test.pending) {
+    console.log(tag('testcase', attrs, false, tag('skipped', {}, true)));
+  } else {
+    console.log(tag('testcase', attrs, true) );
+  }
+}
+
+/**
+ * HTML tag helper.
+ */
+
+function tag(name, attrs, close, content) {
+  var end = close ? '/>' : '>'
+    , pairs = []
+    , tag;
+
+  for (var key in attrs) {
+    pairs.push(key + '="' + escape(attrs[key]) + '"');
+  }
+
+  tag = '<' + name + (pairs.length ? ' ' + pairs.join(' ') : '') + end;
+  if (content) tag += content + '</' + name + end;
+  return tag;
+}
+
+/**
+ * Return cdata escaped CDATA `str`.
+ */
+
+function cdata(str) {
+  return '<![CDATA[' + escape(str) + ']]>';
+}
+
+}); // module: reporters/xunit.js
+
+require.register("runnable.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var EventEmitter = require('browser/events').EventEmitter
+  , debug = require('browser/debug')('runnable');
+
+/**
+ * Save timer references to avoid Sinon interfering (see GH-237).
+ */
+
+var Date = global.Date
+  , setTimeout = global.setTimeout
+  , setInterval = global.setInterval
+  , clearTimeout = global.clearTimeout
+  , clearInterval = global.clearInterval;
+
+/**
+ * Expose `Runnable`.
+ */
+
+module.exports = Runnable;
+
+/**
+ * Initialize a new `Runnable` with the given `title` and callback `fn`.
+ *
+ * @param {String} title
+ * @param {Function} fn
+ * @api private
+ */
+
+function Runnable(title, fn) {
+  this.title = title;
+  this.fn = fn;
+  this.async = fn && fn.length;
+  this.sync = ! this.async;
+  this._timeout = 2000;
+  this.timedOut = false;
+}
+
+/**
+ * Inherit from `EventEmitter.prototype`.
+ */
+
+Runnable.prototype = new EventEmitter;
+Runnable.prototype.constructor = Runnable;
+
+
+/**
+ * Set & get timeout `ms`.
+ *
+ * @param {Number} ms
+ * @return {Runnable|Number} ms or self
+ * @api private
+ */
+
+Runnable.prototype.timeout = function(ms){
+  if (0 == arguments.length) return this._timeout;
+  debug('timeout %d', ms);
+  this._timeout = ms;
+  if (this.timer) this.resetTimeout();
+  return this;
+};
+
+/**
+ * Return the full title generated by recursively
+ * concatenating the parent's full title.
+ *
+ * @return {String}
+ * @api public
+ */
+
+Runnable.prototype.fullTitle = function(){
+  return this.parent.fullTitle() + ' ' + this.title;
+};
+
+/**
+ * Clear the timeout.
+ *
+ * @api private
+ */
+
+Runnable.prototype.clearTimeout = function(){
+  clearTimeout(this.timer);
+};
+
+/**
+ * Inspect the runnable void of private properties.
+ *
+ * @return {String}
+ * @api private
+ */
+
+Runnable.prototype.inspect = function(){
+  return JSON.stringify(this, function(key, val){
+    if ('_' == key[0]) return;
+    if ('parent' == key) return '#<Suite>';
+    if ('ctx' == key) return '#<Context>';
+    return val;
+  }, 2);
+};
+
+/**
+ * Reset the timeout.
+ *
+ * @api private
+ */
+
+Runnable.prototype.resetTimeout = function(){
+  var self = this
+    , ms = this.timeout();
+
+  this.clearTimeout();
+  if (ms) {
+    this.timer = setTimeout(function(){
+      self.callback(new Error('timeout of ' + ms + 'ms exceeded'));
+      self.timedOut = true;
+    }, ms);
+  }
+};
+
+/**
+ * Run the test and invoke `fn(err)`.
+ *
+ * @param {Function} fn
+ * @api private
+ */
+
+Runnable.prototype.run = function(fn){
+  var self = this
+    , ms = this.timeout()
+    , start = new Date
+    , ctx = this.ctx
+    , finished
+    , emitted;
+
+  if (ctx) ctx.runnable(this);
+
+  // timeout
+  if (this.async) {
+    if (ms) {
+      this.timer = setTimeout(function(){
+        done(new Error('timeout of ' + ms + 'ms exceeded'));
+        self.timedOut = true;
+      }, ms);
+    }
+  }
+
+  // called multiple times
+  function multiple(err) {
+    if (emitted) return;
+    emitted = true;
+    self.emit('error', err || new Error('done() called multiple times'));
+  }
+
+  // finished
+  function done(err) {
+    if (self.timedOut) return;
+    if (finished) return multiple(err);
+    self.clearTimeout();
+    self.duration = new Date - start;
+    finished = true;
+    fn(err);
+  }
+
+  // for .resetTimeout()
+  this.callback = done;
+
+  // async
+  if (this.async) {
+    try {
+      this.fn.call(ctx, function(err){
+        if (err instanceof Error) return done(err);
+        if (null != err) return done(new Error('done() invoked with non-Error: ' + err));
+        done();
+      });
+    } catch (err) {
+      done(err);
+    }
+    return;
+  }
+  
+  // sync
+  try {
+    if (!this.pending) this.fn.call(ctx);
+    this.duration = new Date - start;
+    fn();
+  } catch (err) {
+    fn(err);
+  }
+};
+
+}); // module: runnable.js
+
+require.register("runner.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var EventEmitter = require('browser/events').EventEmitter
+  , debug = require('browser/debug')('runner')
+  , Test = require('./test')
+  , utils = require('./utils')
+  , filter = utils.filter
+  , keys = utils.keys
+  , noop = function(){};
+
+/**
+ * Expose `Runner`.
+ */
+
+module.exports = Runner;
+
+/**
+ * Initialize a `Runner` for the given `suite`.
+ *
+ * Events:
+ *
+ *   - `start`  execution started
+ *   - `end`  execution complete
+ *   - `suite`  (suite) test suite execution started
+ *   - `suite end`  (suite) all tests (and sub-suites) have finished
+ *   - `test`  (test) test execution started
+ *   - `test end`  (test) test completed
+ *   - `hook`  (hook) hook execution started
+ *   - `hook end`  (hook) hook complete
+ *   - `pass`  (test) test passed
+ *   - `fail`  (test, err) test failed
+ *
+ * @api public
+ */
+
+function Runner(suite) {
+  var self = this;
+  this._globals = [];
+  this.suite = suite;
+  this.total = suite.total();
+  this.failures = 0;
+  this.on('test end', function(test){ self.checkGlobals(test); });
+  this.on('hook end', function(hook){ self.checkGlobals(hook); });
+  this.grep(/.*/);
+  this.globals(utils.keys(global).concat(['errno']));
+}
+
+/**
+ * Inherit from `EventEmitter.prototype`.
+ */
+
+Runner.prototype = new EventEmitter;
+Runner.prototype.constructor = Runner;
+
+
+/**
+ * Run tests with full titles matching `re`. Updates runner.total
+ * with number of tests matched.
+ *
+ * @param {RegExp} re
+ * @param {Boolean} invert
+ * @return {Runner} for chaining
+ * @api public
+ */
+
+Runner.prototype.grep = function(re, invert){
+  debug('grep %s', re);
+  this._grep = re;
+  this._invert = invert;
+  this.total = this.grepTotal(this.suite);
+  return this;
+};
+
+/**
+ * Returns the number of tests matching the grep search for the
+ * given suite.
+ *
+ * @param {Suite} suite
+ * @return {Number}
+ * @api public
+ */
+
+Runner.prototype.grepTotal = function(suite) {
+  var self = this;
+  var total = 0;
+
+  suite.eachTest(function(test){
+    var match = self._grep.test(test.fullTitle());
+    if (self._invert) match = !match;
+    if (match) total++;
+  });
+
+  return total;
+};
+
+/**
+ * Allow the given `arr` of globals.
+ *
+ * @param {Array} arr
+ * @return {Runner} for chaining
+ * @api public
+ */
+
+Runner.prototype.globals = function(arr){
+  if (0 == arguments.length) return this._globals;
+  debug('globals %j', arr);
+  utils.forEach(arr, function(arr){
+    this._globals.push(arr);
+  }, this);
+  return this;
+};
+
+/**
+ * Check for global variable leaks.
+ *
+ * @api private
+ */
+
+Runner.prototype.checkGlobals = function(test){
+  if (this.ignoreLeaks) return;
+  var leaks = filterLeaks(this._globals);
+
+  this._globals = this._globals.concat(leaks);
+
+  if (leaks.length > 1) {
+    this.fail(test, new Error('global leaks detected: ' + leaks.join(', ') + ''));
+  } else if (leaks.length) {
+    this.fail(test, new Error('global leak detected: ' + leaks[0]));
+  }
+};
+
+/**
+ * Fail the given `test`.
+ *
+ * @param {Test} test
+ * @param {Error} err
+ * @api private
+ */
+
+Runner.prototype.fail = function(test, err){
+  ++this.failures;
+  test.state = 'failed';
+  if ('string' == typeof err) {
+    err = new Error('the string "' + err + '" was thrown, throw an Error :)');
+  }
+  this.emit('fail', test, err);
+};
+
+/**
+ * Fail the given `hook` with `err`.
+ *
+ * Hook failures (currently) hard-end due
+ * to that fact that a failing hook will
+ * surely cause subsequent tests to fail,
+ * causing jumbled reporting.
+ *
+ * @param {Hook} hook
+ * @param {Error} err
+ * @api private
+ */
+
+Runner.prototype.failHook = function(hook, err){
+  this.fail(hook, err);
+  this.emit('end');
+};
+
+/**
+ * Run hook `name` callbacks and then invoke `fn()`.
+ *
+ * @param {String} name
+ * @param {Function} function
+ * @api private
+ */
+
+Runner.prototype.hook = function(name, fn){
+  var suite = this.suite
+    , hooks = suite['_' + name]
+    , ms = suite._timeout
+    , self = this
+    , timer;
+
+  function next(i) {
+    var hook = hooks[i];
+    if (!hook) return fn();
+    self.currentRunnable = hook;
+
+    self.emit('hook', hook);
+
+    hook.on('error', function(err){
+      self.failHook(hook, err);
+    });
+
+    hook.run(function(err){
+      hook.removeAllListeners('error');
+      var testError = hook.error();
+      if (testError) self.fail(self.test, testError);
+      if (err) return self.failHook(hook, err);
+      self.emit('hook end', hook);
+      next(++i);
+    });
+  }
+
+  process.nextTick(function(){
+    next(0);
+  });
+};
+
+/**
+ * Run hook `name` for the given array of `suites`
+ * in order, and callback `fn(err)`.
+ *
+ * @param {String} name
+ * @param {Array} suites
+ * @param {Function} fn
+ * @api private
+ */
+
+Runner.prototype.hooks = function(name, suites, fn){
+  var self = this
+    , orig = this.suite;
+
+  function next(suite) {
+    self.suite = suite;
+
+    if (!suite) {
+      self.suite = orig;
+      return fn();
+    }
+
+    self.hook(name, function(err){
+      if (err) {
+        self.suite = orig;
+        return fn(err);
+      }
+
+      next(suites.pop());
+    });
+  }
+
+  next(suites.pop());
+};
+
+/**
+ * Run hooks from the top level down.
+ *
+ * @param {String} name
+ * @param {Function} fn
+ * @api private
+ */
+
+Runner.prototype.hookUp = function(name, fn){
+  var suites = [this.suite].concat(this.parents()).reverse();
+  this.hooks(name, suites, fn);
+};
+
+/**
+ * Run hooks from the bottom up.
+ *
+ * @param {String} name
+ * @param {Function} fn
+ * @api private
+ */
+
+Runner.prototype.hookDown = function(name, fn){
+  var suites = [this.suite].concat(this.parents());
+  this.hooks(name, suites, fn);
+};
+
+/**
+ * Return an array of parent Suites from
+ * closest to furthest.
+ *
+ * @return {Array}
+ * @api private
+ */
+
+Runner.prototype.parents = function(){
+  var suite = this.suite
+    , suites = [];
+  while (suite = suite.parent) suites.push(suite);
+  return suites;
+};
+
+/**
+ * Run the current test and callback `fn(err)`.
+ *
+ * @param {Function} fn
+ * @api private
+ */
+
+Runner.prototype.runTest = function(fn){
+  var test = this.test
+    , self = this;
+
+  try {
+    test.on('error', function(err){
+      self.fail(test, err);
+    });
+    test.run(fn);
+  } catch (err) {
+    fn(err);
+  }
+};
+
+/**
+ * Run tests in the given `suite` and invoke
+ * the callback `fn()` when complete.
+ *
+ * @param {Suite} suite
+ * @param {Function} fn
+ * @api private
+ */
+
+Runner.prototype.runTests = function(suite, fn){
+  var self = this
+    , tests = suite.tests
+    , test;
+
+  function next(err) {
+    // if we bail after first err
+    if (self.failures && suite._bail) return fn();
+
+    // next test
+    test = tests.shift();
+
+    // all done
+    if (!test) return fn();
+
+    // grep
+    var match = self._grep.test(test.fullTitle());
+    if (self._invert) match = !match;
+    if (!match) return next();
+
+    // pending
+    if (test.pending) {
+      self.emit('pending', test);
+      self.emit('test end', test);
+      return next();
+    }
+
+    // execute test and hook(s)
+    self.emit('test', self.test = test);
+    self.hookDown('beforeEach', function(){
+      self.currentRunnable = self.test;
+      self.runTest(function(err){
+        test = self.test;
+
+        if (err) {
+          self.fail(test, err);
+          self.emit('test end', test);
+          return self.hookUp('afterEach', next);
+        }
+
+        test.state = 'passed';
+        self.emit('pass', test);
+        self.emit('test end', test);
+        self.hookUp('afterEach', next);
+      });
+    });
+  }
+
+  this.next = next;
+  next();
+};
+
+/**
+ * Run the given `suite` and invoke the
+ * callback `fn()` when complete.
+ *
+ * @param {Suite} suite
+ * @param {Function} fn
+ * @api private
+ */
+
+Runner.prototype.runSuite = function(suite, fn){
+  var total = this.grepTotal(suite)
+    , self = this
+    , i = 0;
+
+  debug('run suite %s', suite.fullTitle());
+
+  if (!total) return fn();
+
+  this.emit('suite', this.suite = suite);
+
+  function next() {
+    var curr = suite.suites[i++];
+    if (!curr) return done();
+    self.runSuite(curr, next);
+  }
+
+  function done() {
+    self.suite = suite;
+    self.hook('afterAll', function(){
+      self.emit('suite end', suite);
+      fn();
+    });
+  }
+
+  this.hook('beforeAll', function(){
+    self.runTests(suite, next);
+  });
+};
+
+/**
+ * Handle uncaught exceptions.
+ *
+ * @param {Error} err
+ * @api private
+ */
+
+Runner.prototype.uncaught = function(err){
+  debug('uncaught exception');
+  var runnable = this.currentRunnable;
+  if ('failed' == runnable.state) return;
+  runnable.clearTimeout();
+  err.uncaught = true;
+  this.fail(runnable, err);
+
+  // recover from test
+  if ('test' == runnable.type) {
+    this.emit('test end', runnable);
+    this.hookUp('afterEach', this.next);
+    return;
+  }
+
+  // bail on hooks
+  this.emit('end');
+};
+
+/**
+ * Run the root suite and invoke `fn(failures)`
+ * on completion.
+ *
+ * @param {Function} fn
+ * @return {Runner} for chaining
+ * @api public
+ */
+
+Runner.prototype.run = function(fn){
+  var self = this
+    , fn = fn || function(){};
+
+  debug('start');
+
+  // uncaught callback
+  function uncaught(err) {
+    self.uncaught(err);
+  }
+
+  // callback
+  this.on('end', function(){
+    debug('end');
+    process.removeListener('uncaughtException', uncaught);
+    fn(self.failures);
+  });
+
+  // run suites
+  this.emit('start');
+  this.runSuite(this.suite, function(){
+    debug('finished running');
+    self.emit('end');
+  });
+
+  // uncaught exception
+  process.on('uncaughtException', uncaught);
+
+  return this;
+};
+
+/**
+ * Filter leaks with the given globals flagged as `ok`.
+ *
+ * @param {Array} ok
+ * @return {Array}
+ * @api private
+ */
+
+function filterLeaks(ok) {
+  return filter(keys(global), function(key){
+    var matched = filter(ok, function(ok){
+      if (~ok.indexOf('*')) return 0 == key.indexOf(ok.split('*')[0]);
+      return key == ok;
+    });
+    return matched.length == 0 && (!global.navigator || 'onerror' !== key);
+  });
+}
+}); // module: runner.js
+
+require.register("suite.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var EventEmitter = require('browser/events').EventEmitter
+  , debug = require('browser/debug')('suite')
+  , utils = require('./utils')
+  , Hook = require('./hook');
+
+/**
+ * Expose `Suite`.
+ */
+
+exports = module.exports = Suite;
+
+/**
+ * Create a new `Suite` with the given `title`
+ * and parent `Suite`. When a suite with the
+ * same title is already present, that suite
+ * is returned to provide nicer reporter
+ * and more flexible meta-testing.
+ *
+ * @param {Suite} parent
+ * @param {String} title
+ * @return {Suite}
+ * @api public
+ */
+
+exports.create = function(parent, title){
+  var suite = new Suite(title, parent.ctx);
+  suite.parent = parent;
+  title = suite.fullTitle();
+  parent.addSuite(suite);
+  return suite;
+};
+
+/**
+ * Initialize a new `Suite` with the given
+ * `title` and `ctx`.
+ *
+ * @param {String} title
+ * @param {Context} ctx
+ * @api private
+ */
+
+function Suite(title, ctx) {
+  this.title = title;
+  this.ctx = ctx;
+  this.suites = [];
+  this.tests = [];
+  this._beforeEach = [];
+  this._beforeAll = [];
+  this._afterEach = [];
+  this._afterAll = [];
+  this.root = !title;
+  this._timeout = 2000;
+  this._bail = false;
+}
+
+/**
+ * Inherit from `EventEmitter.prototype`.
+ */
+
+Suite.prototype = new EventEmitter;
+Suite.prototype.constructor = Suite;
+
+
+/**
+ * Return a clone of this `Suite`.
+ *
+ * @return {Suite}
+ * @api private
+ */
+
+Suite.prototype.clone = function(){
+  var suite = new Suite(this.title);
+  debug('clone');
+  suite.ctx = this.ctx;
+  suite.timeout(this.timeout());
+  suite.bail(this.bail());
+  return suite;
+};
+
+/**
+ * Set timeout `ms` or short-hand such as "2s".
+ *
+ * @param {Number|String} ms
+ * @return {Suite|Number} for chaining
+ * @api private
+ */
+
+Suite.prototype.timeout = function(ms){
+  if (0 == arguments.length) return this._timeout;
+  if (String(ms).match(/s$/)) ms = parseFloat(ms) * 1000;
+  debug('timeout %d', ms);
+  this._timeout = parseInt(ms, 10);
+  return this;
+};
+
+/**
+ * Sets whether to bail after first error.
+ *
+ * @parma {Boolean} bail
+ * @return {Suite|Number} for chaining
+ * @api private
+ */
+
+Suite.prototype.bail = function(bail){
+  if (0 == arguments.length) return this._bail;
+  debug('bail %s', bail);
+  this._bail = bail;
+  return this;
+};
+
+/**
+ * Run `fn(test[, done])` before running tests.
+ *
+ * @param {Function} fn
+ * @return {Suite} for chaining
+ * @api private
+ */
+
+Suite.prototype.beforeAll = function(fn){
+  var hook = new Hook('"before all" hook', fn);
+  hook.parent = this;
+  hook.timeout(this.timeout());
+  hook.ctx = this.ctx;
+  this._beforeAll.push(hook);
+  this.emit('beforeAll', hook);
+  return this;
+};
+
+/**
+ * Run `fn(test[, done])` after running tests.
+ *
+ * @param {Function} fn
+ * @return {Suite} for chaining
+ * @api private
+ */
+
+Suite.prototype.afterAll = function(fn){
+  var hook = new Hook('"after all" hook', fn);
+  hook.parent = this;
+  hook.timeout(this.timeout());
+  hook.ctx = this.ctx;
+  this._afterAll.push(hook);
+  this.emit('afterAll', hook);
+  return this;
+};
+
+/**
+ * Run `fn(test[, done])` before each test case.
+ *
+ * @param {Function} fn
+ * @return {Suite} for chaining
+ * @api private
+ */
+
+Suite.prototype.beforeEach = function(fn){
+  var hook = new Hook('"before each" hook', fn);
+  hook.parent = this;
+  hook.timeout(this.timeout());
+  hook.ctx = this.ctx;
+  this._beforeEach.push(hook);
+  this.emit('beforeEach', hook);
+  return this;
+};
+
+/**
+ * Run `fn(test[, done])` after each test case.
+ *
+ * @param {Function} fn
+ * @return {Suite} for chaining
+ * @api private
+ */
+
+Suite.prototype.afterEach = function(fn){
+  var hook = new Hook('"after each" hook', fn);
+  hook.parent = this;
+  hook.timeout(this.timeout());
+  hook.ctx = this.ctx;
+  this._afterEach.push(hook);
+  this.emit('afterEach', hook);
+  return this;
+};
+
+/**
+ * Add a test `suite`.
+ *
+ * @param {Suite} suite
+ * @return {Suite} for chaining
+ * @api private
+ */
+
+Suite.prototype.addSuite = function(suite){
+  suite.parent = this;
+  suite.timeout(this.timeout());
+  suite.bail(this.bail());
+  this.suites.push(suite);
+  this.emit('suite', suite);
+  return this;
+};
+
+/**
+ * Add a `test` to this suite.
+ *
+ * @param {Test} test
+ * @return {Suite} for chaining
+ * @api private
+ */
+
+Suite.prototype.addTest = function(test){
+  test.parent = this;
+  test.timeout(this.timeout());
+  test.ctx = this.ctx;
+  this.tests.push(test);
+  this.emit('test', test);
+  return this;
+};
+
+/**
+ * Return the full title generated by recursively
+ * concatenating the parent's full title.
+ *
+ * @return {String}
+ * @api public
+ */
+
+Suite.prototype.fullTitle = function(){
+  if (this.parent) {
+    var full = this.parent.fullTitle();
+    if (full) return full + ' ' + this.title;
+  }
+  return this.title;
+};
+
+/**
+ * Return the total number of tests.
+ *
+ * @return {Number}
+ * @api public
+ */
+
+Suite.prototype.total = function(){
+  return utils.reduce(this.suites, function(sum, suite){
+    return sum + suite.total();
+  }, 0) + this.tests.length;
+};
+
+/**
+ * Iterates through each suite recursively to find
+ * all tests. Applies a function in the format
+ * `fn(test)`.
+ *
+ * @param {Function} fn
+ * @return {Suite}
+ * @api private
+ */
+
+Suite.prototype.eachTest = function(fn){
+  utils.forEach(this.tests, fn);
+  utils.forEach(this.suites, function(suite){
+    suite.eachTest(fn);
+  });
+  return this;
+};
+
+}); // module: suite.js
+
+require.register("test.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var Runnable = require('./runnable');
+
+/**
+ * Expose `Test`.
+ */
+
+module.exports = Test;
+
+/**
+ * Initialize a new `Test` with the given `title` and callback `fn`.
+ *
+ * @param {String} title
+ * @param {Function} fn
+ * @api private
+ */
+
+function Test(title, fn) {
+  Runnable.call(this, title, fn);
+  this.pending = !fn;
+  this.type = 'test';
+}
+
+/**
+ * Inherit from `Runnable.prototype`.
+ */
+
+Test.prototype = new Runnable;
+Test.prototype.constructor = Test;
+
+
+}); // module: test.js
+
+require.register("utils.js", function(module, exports, require){
+
+/**
+ * Module dependencies.
+ */
+
+var fs = require('browser/fs')
+  , path = require('browser/path')
+  , join = path.join
+  , debug = require('browser/debug')('watch');
+
+/**
+ * Ignored directories.
+ */
+
+var ignore = ['node_modules', '.git'];
+
+/**
+ * Escape special characters in the given string of html.
+ *
+ * @param  {String} html
+ * @return {String}
+ * @api private
+ */
+
+exports.escape = function(html) {
+  return String(html)
+    .replace(/&/g, '&')
+    .replace(/"/g, '"')
+    .replace(/</g, '<')
+    .replace(/>/g, '>');
+};
+
+/**
+ * Array#forEach (<=IE8)
+ *
+ * @param {Array} array
+ * @param {Function} fn
+ * @param {Object} scope
+ * @api private
+ */
+
+exports.forEach = function(arr, fn, scope) {
+  for (var i = 0, l = arr.length; i < l; i++)
+    fn.call(scope, arr[i], i);
+};
+
+/**
+ * Array#indexOf (<=IE8)
+ *
+ * @parma {Array} arr
+ * @param {Object} obj to find index of
+ * @param {Number} start
+ * @api private
+ */
+
+exports.indexOf = function (arr, obj, start) {
+  for (var i = start || 0, l = arr.length; i < l; i++) {
+    if (arr[i] === obj)
+      return i;
+  }
+  return -1;
+};
+
+/**
+ * Array#reduce (<=IE8)
+ * 
+ * @param {Array} array
+ * @param {Function} fn
+ * @param {Object} initial value
+ * @param {Object} scope
+ * @api private
+ */
+
+exports.reduce = function(arr, fn, val, scope) {
+  var rval = val;
+
+  for (var i = 0, l = arr.length; i < l; i++) {
+    rval = fn.call(scope, rval, arr[i], i, arr);
+  }
+
+  return rval;
+};
+
+/**
+ * Array#filter (<=IE8)
+ *
+ * @param {Array} array
+ * @param {Function} fn
+ * @param {Object} scope
+ * @api private
+ */
+
+exports.filter = function(arr, fn, scope) {
+  var ret = [];
+
+  for (var i = 0, l = arr.length; i < l; i++) {
+    var val = arr[i];
+    if (fn.call(scope, val, i, arr))
+      ret.push(val);
+  }
+
+  return ret;
+};
+
+/**
+ * Object.keys (<=IE8)
+ *
+ * @param {Object} obj
+ * @return {Array} keys
+ * @api private
+ */
+
+exports.keys = Object.keys || function(obj) {
+  var keys = []
+    , has = Object.prototype.hasOwnProperty // for `window` on <=IE8
+
+  for (var key in obj) {
+    if (has.call(obj, key)) {
+      keys.push(key);
+    }
+  }
+
+  return keys;
+};
+
+/**
+ * Watch the given `files` for changes
+ * and invoke `fn(file)` on modification.
+ *
+ * @param {Array} files
+ * @param {Function} fn
+ * @api private
+ */
+
+exports.watch = function(files, fn){
+  var options = { interval: 100 };
+  files.forEach(function(file){
+    debug('file %s', file);
+    fs.watchFile(file, options, function(curr, prev){
+      if (prev.mtime < curr.mtime) fn(file);
+    });
+  });
+};
+
+/**
+ * Ignored files.
+ */
+
+function ignored(path){
+  return !~ignore.indexOf(path);
+}
+
+/**
+ * Lookup files in the given `dir`.
+ *
+ * @return {Array}
+ * @api private
+ */
+
+exports.files = function(dir, ret){
+  ret = ret || [];
+
+  fs.readdirSync(dir)
+  .filter(ignored)
+  .forEach(function(path){
+    path = join(dir, path);
+    if (fs.statSync(path).isDirectory()) {
+      exports.files(path, ret);
+    } else if (path.match(/\.(js|coffee)$/)) {
+      ret.push(path);
+    }
+  });
+
+  return ret;
+};
+
+/**
+ * Compute a slug from the given `str`.
+ *
+ * @param {String} str
+ * @return {String}
+ * @api private
+ */
+
+exports.slug = function(str){
+  return str
+    .toLowerCase()
+    .replace(/ +/g, '-')
+    .replace(/[^-\w]/g, '');
+};
+
+/**
+ * Strip the function definition from `str`,
+ * and re-indent for pre whitespace.
+ */
+
+exports.clean = function(str) {
+  str = str
+    .replace(/^function *$.*$ *{/, '')
+    .replace(/\s+\}$/, '');
+
+  var spaces = str.match(/^\n?( *)/)[1].length
+    , re = new RegExp('^ {' + spaces + '}', 'gm');
+
+  str = str.replace(re, '');
+
+  return str.trim();
+};
+
+/**
+ * Escape regular expression characters in `str`.
+ *
+ * @param {String} str
+ * @return {String}
+ * @api private
+ */
+
+exports.escapeRegexp = function(str){
+  return str.replace(/[-\\^$*+?.()|[\]{}]/g, "\\$&");
+};
+}); // module: utils.js
+/**
+ * Node shims.
+ *
+ * These are meant only to allow
+ * mocha.js to run untouched, not
+ * to allow running node code in
+ * the browser.
+ */
+
+process = {};
+process.exit = function(status){};
+process.stdout = {};
+global = window;
+
+/**
+ * next tick implementation.
+ */
+
+process.nextTick = (function(){
+  // postMessage behaves badly on IE8
+  if (window.ActiveXObject || !window.postMessage) {
+    return function(fn){ fn() };
+  }
+
+  // based on setZeroTimeout by David Baron
+  // - http://dbaron.org/log/20100309-faster-timeouts
+  var timeouts = []
+    , name = 'mocha-zero-timeout'
+
+  window.addEventListener('message', function(e){
+    if (e.source == window && e.data == name) {
+      if (e.stopPropagation) e.stopPropagation();
+      if (timeouts.length) timeouts.shift()();
+    }
+  }, true);
+
+  return function(fn){
+    timeouts.push(fn);
+    window.postMessage(name, '*');
+  }
+})();
+
+/**
+ * Remove uncaughtException listener.
+ */
+
+process.removeListener = function(e){
+  if ('uncaughtException' == e) {
+    window.onerror = null;
+  }
+};
+
+/**
+ * Implements uncaughtException listener.
+ */
+
+process.on = function(e, fn){
+  if ('uncaughtException' == e) {
+    window.onerror = fn;
+  }
+};
+
+/**
+ * Expose mocha.
+ */
+
+window.mocha = require('mocha');
+
+// boot
+;(function(){
+  var utils = mocha.utils
+    , options = {}
+
+  mocha.suite = new mocha.Suite('', new mocha.Context());
+
+  /**
+   * Highlight the given string of `js`.
+   */
+
+  function highlight(js) {
+    return js
+      .replace(/</g, '<')
+      .replace(/>/g, '>')
+      .replace(/\/\/(.*)/gm, '<span class="comment">//$1</span>')
+      .replace(/('.*?')/gm, '<span class="string">$1</span>')
+      .replace(/(\d+\.\d+)/gm, '<span class="number">$1</span>')
+      .replace(/(\d+)/gm, '<span class="number">$1</span>')
+      .replace(/\bnew *(\w+)/gm, '<span class="keyword">new</span> <span class="init">$1</span>')
+      .replace(/\b(function|new|throw|return|var|if|else)\b/gm, '<span class="keyword">$1</span>')
+  }
+
+  /**
+   * Highlight code contents.
+   */
+
+  function highlightCode() {
+    var code = document.getElementsByTagName('code');
+    for (var i = 0, len = code.length; i < len; ++i) {
+      code[i].innerHTML = highlight(code[i].innerHTML);
+    }
+  }
+
+  /**
+   * Parse the given `qs`.
+   */
+
+  function parse(qs) {
+    return utils.reduce(qs.replace('?', '').split('&'), function(obj, pair){
+      var i = pair.indexOf('=')
+        , key = pair.slice(0, i)
+        , val = pair.slice(++i);
+
+      obj[key] = decodeURIComponent(val);
+      return obj;
+    }, {});
+  }
+
+  /**
+   * Setup mocha with the given setting options.
+   */
+
+  mocha.setup = function(opts){
+    if ('string' === typeof opts) options.ui = opts;
+    else options = opts;
+
+    ui = mocha.interfaces[options.ui];
+    if (!ui) throw new Error('invalid mocha interface "' + ui + '"');
+    if (options.timeout) mocha.suite.timeout(options.timeout);
+    ui(mocha.suite);
+    mocha.suite.emit('pre-require', window);
+  };
+
+  /**
+   * Run mocha, returning the Runner.
+   */
+
+  mocha.run = function(fn){
+    mocha.suite.emit('run');
+    var runner = new mocha.Runner(mocha.suite);
+    var Reporter = options.reporter || mocha.reporters.HTML;
+    var reporter = new Reporter(runner);
+    var query = parse(window.location.search || "");
+    if (query.grep) runner.grep(new RegExp(query.grep));
+    if (options.ignoreLeaks) runner.ignoreLeaks = true;
+    if (options.globals) runner.globals(options.globals);
+    runner.globals(['location']);
+    runner.on('end', highlightCode);
+    return runner.run(fn);
+  };
+})();
+})();
\ No newline at end of file
diff --git a/server/node_modules/connect-sqlite3/test/test.js b/server/node_modules/connect-sqlite3/test/test.js
new file mode 100644
index 0000000..540aae8
--- /dev/null
+++ b/server/node_modules/connect-sqlite3/test/test.js
@@ -0,0 +1,124 @@
+var should = require('should'),
+    session = require('express-session'),
+    util = require('util'),
+    SQLiteStore = require('../lib/connect-sqlite3.js')(session);
+  
+describe('connect-sqlite3 basic test suite', function() {
+    before(function() {
+        this.memStore = new SQLiteStore({db: ':memory:', dir: 'dbs'});
+    });
+
+    after(function() {
+        //this.memStore.close();
+    });
+
+    it('it should save a new session record', function(done) {
+        this.memStore.set('1111222233334444', {cookie: {maxAge:2000}, name: 'sample name'}, function(err, rows) {
+            should.not.exist(err, 'set() returned an error');
+            rows.should.be.empty;
+            done();
+        });
+    });
+
+
+    it('it should retrieve an active session', function(done) {
+        this.memStore.get('1111222233334444', function(err, session) {
+            should.not.exist(err, 'get() returned an error');
+            should.exist(session);
+            (session).should.eql({cookie: {maxAge:2000}, name: 'sample name'});
+            done();
+        });
+    });
+
+    it('it should gracefully handle retrieving an unkonwn session', function(done) {
+        this.memStore.get('hope-and-change', function(err, rows) {
+            should.not.exist(err, 'get() unknown session returned an error');
+            should.equal(undefined, rows, 'unknown session is not undefined');
+            done();
+        });
+    });
+
+    it('it should only contain one session', function(done) {
+        this.memStore.length(function(err, len) {
+            should.not.exist(err, 'session count returned an error');
+            should.exist(len);
+            len.should.equal(1);
+            done();
+        });
+    });
+
+    it('it should clear all session records', function(done) {
+        var that = this;
+        this.memStore.clear(function(err, success) {
+            should.not.exist(err, 'clear returned an error');
+            success.should.be.true;
+
+            that.memStore.length(function(err, len) {
+                should.not.exist(err, 'session count after clear returned an error');
+                should.exist(len);
+                len.should.equal(0);
+                done();
+            });
+        });
+    });
+
+    it('it should destroy a session', function(done) {
+        var that = this;
+        this.memStore.set('555666777', {cookie: {maxAge:1000}, name: 'Rob Dobilina'}, function(err, rows) {
+            should.not.exist(err, 'set() returned an error');
+            rows.should.be.empty;
+            
+            that.memStore.destroy('555666777', function(err) {
+                should.not.exist(err, 'destroy returned an error');
+
+                that.memStore.length(function(err, len) {
+                    should.not.exist(err, 'session count after destroy returned an error');
+                    should.exist(len);
+                    len.should.equal(0);
+                    done();                        
+                });                  
+            });
+        });
+    });
+
+
+
+});
+
+
+describe('connect-sqlite3 shared cache', function() {
+  it("should retrieve in one cached session what's stored in another.", function(done) {
+    var cwd = process.cwd();
+    var memStore = new SQLiteStore({db: 'file::memory:?cache=shared', mode: 0x20046});
+    process.chdir('..'); // Ensure we aren't opening a shared disk file
+    var memStore2 = new SQLiteStore({db: 'file::memory:?cache=shared', mode: 0x20046});
+
+    memStore.set('1111222233334444', {cookie: {maxAge:2011}, name: 'sample name'}, function(err, rows) {
+      process.chdir(cwd); // Restore dir
+      should.not.exist(err, 'set() returned an error');
+      rows.should.be.empty;
+      memStore2.get('1111222233334444', function(err, session) {
+        should.not.exist(err, 'get() returned an error');
+        should.exist(session);
+        (session).should.eql({cookie: {maxAge:2011}, name: 'sample name'});
+        done();
+      });
+    });
+  });
+
+  it("should not retrieve in one uncached session what's stored in another.", function(done) {
+    var memStore = new SQLiteStore({db: ':memory:'});
+    var memStore2 = new SQLiteStore({db: ':memory:'});
+
+    memStore.set('1111222233334444', {cookie: {maxAge:2011}, name: 'sample name'}, function(err, rows) {
+      should.not.exist(err, 'set() returned an error');
+      rows.should.be.empty;
+      memStore2.get('1111222233334444', function(err, session) {
+        should.not.exist(err, 'get() returned an error');
+        should.not.exist(session);
+        done();
+      });
+    });
+  });
+});
+  
diff --git a/server/node_modules/connect-sqlite3/test/tests.html b/server/node_modules/connect-sqlite3/test/tests.html
new file mode 100644
index 0000000..b65b16b
--- /dev/null
+++ b/server/node_modules/connect-sqlite3/test/tests.html
@@ -0,0 +1,16 @@
+<html>
+  <head>
+    <title>Mocha</title>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+    <link rel="stylesheet" href="mocha.css" />
+  </head>
+  <body>
+    <div id="mocha"></div>
+    <script src="mocha.js"></script>
+    <script>mocha.setup('bdd')</script>
+    <script src="tests.js"></script>
+    <script>
+      mocha.run();
+    </script>
+  </body>
+</html>
diff --git a/server/node_modules/console-control-strings/LICENSE b/server/node_modules/console-control-strings/LICENSE
new file mode 100644
index 0000000..e756052
--- /dev/null
+++ b/server/node_modules/console-control-strings/LICENSE
@@ -0,0 +1,13 @@
+Copyright (c) 2014, Rebecca Turner <me@re-becca.org>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/console-control-strings/README.md b/server/node_modules/console-control-strings/README.md
new file mode 100644
index 0000000..f58cc8d
--- /dev/null
+++ b/server/node_modules/console-control-strings/README.md
@@ -0,0 +1,145 @@
+# Console Control Strings
+
+A library of cross-platform tested terminal/console command strings for
+doing things like color and cursor positioning.  This is a subset of both
+ansi and vt100.  All control codes included work on both Windows & Unix-like
+OSes, except where noted.
+
+## Usage
+
+```js
+var consoleControl = require('console-control-strings')
+
+console.log(consoleControl.color('blue','bgRed', 'bold') + 'hi there' + consoleControl.color('reset'))
+process.stdout.write(consoleControl.goto(75, 10))
+```
+
+## Why Another?
+
+There are tons of libraries similar to this one.  I wanted one that was:
+
+1. Very clear about compatibility goals.
+2. Could emit, for instance, a start color code without an end one.
+3. Returned strings w/o writing to streams.
+4. Was not weighed down with other unrelated baggage.
+
+## Functions
+
+### var code = consoleControl.up(_num = 1_)
+
+Returns the escape sequence to move _num_ lines up.
+
+### var code = consoleControl.down(_num = 1_)
+
+Returns the escape sequence to move _num_ lines down.
+
+### var code = consoleControl.forward(_num = 1_)
+
+Returns the escape sequence to move _num_ lines righ.
+
+### var code = consoleControl.back(_num = 1_)
+
+Returns the escape sequence to move _num_ lines left.
+
+### var code = consoleControl.nextLine(_num = 1_)
+
+Returns the escape sequence to move _num_ lines down and to the beginning of
+the line.
+
+### var code = consoleControl.previousLine(_num = 1_)
+
+Returns the escape sequence to move _num_ lines up and to the beginning of
+the line.
+
+### var code = consoleControl.eraseData()
+
+Returns the escape sequence to erase everything from the current cursor
+position to the bottom right of the screen.  This is line based, so it
+erases the remainder of the current line and all following lines.
+
+### var code = consoleControl.eraseLine()
+
+Returns the escape sequence to erase to the end of the current line.
+
+### var code = consoleControl.goto(_x_, _y_)
+
+Returns the escape sequence to move the cursor to the designated position. 
+Note that the origin is _1, 1_ not _0, 0_.
+
+### var code = consoleControl.gotoSOL()
+
+Returns the escape sequence to move the cursor to the beginning of the
+current line. (That is, it returns a carriage return, `\r`.)
+
+### var code = consoleControl.beep()
+
+Returns the escape sequence to cause the termianl to beep.  (That is, it
+returns unicode character `\x0007`, a Control-G.)
+
+### var code = consoleControl.hideCursor()
+
+Returns the escape sequence to hide the cursor.
+
+### var code = consoleControl.showCursor()
+
+Returns the escape sequence to show the cursor.
+
+### var code = consoleControl.color(_colors = []_)
+
+### var code = consoleControl.color(_color1_, _color2_, _…_, _colorn_)
+
+Returns the escape sequence to set the current terminal display attributes
+(mostly colors).  Arguments can either be a list of attributes or an array
+of attributes.  The difference between passing in an array or list of colors
+and calling `.color` separately for each one, is that in the former case a
+single escape sequence will be produced where as in the latter each change
+will have its own distinct escape sequence.  Each attribute can be one of:
+
+* Reset:
+  * **reset** – Reset all attributes to the terminal default.
+* Styles:
+  * **bold** – Display text as bold.  In some terminals this means using a
+    bold font, in others this means changing the color.  In some it means
+    both.
+  * **italic** – Display text as italic. This is not available in most Windows terminals.
+  * **underline** – Underline text. This is not available in most Windows Terminals.
+  * **inverse** – Invert the foreground and background colors.
+  * **stopBold** – Do not display text as bold.
+  * **stopItalic** – Do not display text as italic.
+  * **stopUnderline** – Do not underline text.
+  * **stopInverse** – Do not invert foreground and background.
+* Colors:
+  * **white**
+  * **black**
+  * **blue**
+  * **cyan**
+  * **green**
+  * **magenta**
+  * **red**
+  * **yellow**
+  * **grey** / **brightBlack**
+  * **brightRed**
+  * **brightGreen**
+  * **brightYellow**
+  * **brightBlue**
+  * **brightMagenta**
+  * **brightCyan**
+  * **brightWhite**
+* Background Colors:
+  * **bgWhite**
+  * **bgBlack**
+  * **bgBlue**
+  * **bgCyan**
+  * **bgGreen**
+  * **bgMagenta**
+  * **bgRed**
+  * **bgYellow**
+  * **bgGrey** / **bgBrightBlack**
+  * **bgBrightRed**
+  * **bgBrightGreen**
+  * **bgBrightYellow**
+  * **bgBrightBlue**
+  * **bgBrightMagenta**
+  * **bgBrightCyan**
+  * **bgBrightWhite**
+
diff --git a/server/node_modules/console-control-strings/README.md~ b/server/node_modules/console-control-strings/README.md~
new file mode 100644
index 0000000..6eb34e8
--- /dev/null
+++ b/server/node_modules/console-control-strings/README.md~
@@ -0,0 +1,140 @@
+# Console Control Strings
+
+A library of cross-platform tested terminal/console command strings for
+doing things like color and cursor positioning.  This is a subset of both
+ansi and vt100.  All control codes included work on both Windows & Unix-like
+OSes, except where noted.
+
+## Usage
+
+```js
+var consoleControl = require('console-control-strings')
+
+console.log(consoleControl.color('blue','bgRed', 'bold') + 'hi there' + consoleControl.color('reset'))
+process.stdout.write(consoleControl.goto(75, 10))
+```
+
+## Why Another?
+
+There are tons of libraries similar to this one.  I wanted one that was:
+
+1. Very clear about compatibility goals.
+2. Could emit, for instance, a start color code without an end one.
+3. Returned strings w/o writing to streams.
+4. Was not weighed down with other unrelated baggage.
+
+## Functions
+
+### var code = consoleControl.up(_num = 1_)
+
+Returns the escape sequence to move _num_ lines up.
+
+### var code = consoleControl.down(_num = 1_)
+
+Returns the escape sequence to move _num_ lines down.
+
+### var code = consoleControl.forward(_num = 1_)
+
+Returns the escape sequence to move _num_ lines righ.
+
+### var code = consoleControl.back(_num = 1_)
+
+Returns the escape sequence to move _num_ lines left.
+
+### var code = consoleControl.nextLine(_num = 1_)
+
+Returns the escape sequence to move _num_ lines down and to the beginning of
+the line.
+
+### var code = consoleControl.previousLine(_num = 1_)
+
+Returns the escape sequence to move _num_ lines up and to the beginning of
+the line.
+
+### var code = consoleControl.eraseData()
+
+Returns the escape sequence to erase everything from the current cursor
+position to the bottom right of the screen.  This is line based, so it
+erases the remainder of the current line and all following lines.
+
+### var code = consoleControl.eraseLine()
+
+Returns the escape sequence to erase to the end of the current line.
+
+### var code = consoleControl.goto(_x_, _y_)
+
+Returns the escape sequence to move the cursor to the designated position. 
+Note that the origin is _1, 1_ not _0, 0_.
+
+### var code = consoleControl.gotoSOL()
+
+Returns the escape sequence to move the cursor to the beginning of the
+current line. (That is, it returns a carriage return, `\r`.)
+
+### var code = consoleControl.hideCursor()
+
+Returns the escape sequence to hide the cursor.
+
+### var code = consoleControl.showCursor()
+
+Returns the escape sequence to show the cursor.
+
+### var code = consoleControl.color(_colors = []_)
+
+### var code = consoleControl.color(_color1_, _color2_, _…_, _colorn_)
+
+Returns the escape sequence to set the current terminal display attributes
+(mostly colors).  Arguments can either be a list of attributes or an array
+of attributes.  The difference between passing in an array or list of colors
+and calling `.color` separately for each one, is that in the former case a
+single escape sequence will be produced where as in the latter each change
+will have its own distinct escape sequence.  Each attribute can be one of:
+
+* Reset:
+  * **reset** – Reset all attributes to the terminal default.
+* Styles:
+  * **bold** – Display text as bold.  In some terminals this means using a
+    bold font, in others this means changing the color.  In some it means
+    both.
+  * **italic** – Display text as italic. This is not available in most Windows terminals.
+  * **underline** – Underline text. This is not available in most Windows Terminals.
+  * **inverse** – Invert the foreground and background colors.
+  * **stopBold** – Do not display text as bold.
+  * **stopItalic** – Do not display text as italic.
+  * **stopUnderline** – Do not underline text.
+  * **stopInverse** – Do not invert foreground and background.
+* Colors:
+  * **white**
+  * **black**
+  * **blue**
+  * **cyan**
+  * **green**
+  * **magenta**
+  * **red**
+  * **yellow**
+  * **grey** / **brightBlack**
+  * **brightRed**
+  * **brightGreen**
+  * **brightYellow**
+  * **brightBlue**
+  * **brightMagenta**
+  * **brightCyan**
+  * **brightWhite**
+* Background Colors:
+  * **bgWhite**
+  * **bgBlack**
+  * **bgBlue**
+  * **bgCyan**
+  * **bgGreen**
+  * **bgMagenta**
+  * **bgRed**
+  * **bgYellow**
+  * **bgGrey** / **bgBrightBlack**
+  * **bgBrightRed**
+  * **bgBrightGreen**
+  * **bgBrightYellow**
+  * **bgBrightBlue**
+  * **bgBrightMagenta**
+  * **bgBrightCyan**
+  * **bgBrightWhite**
+
diff --git a/server/node_modules/console-control-strings/index.js b/server/node_modules/console-control-strings/index.js
new file mode 100644
index 0000000..bf89034
--- /dev/null
+++ b/server/node_modules/console-control-strings/index.js
@@ -0,0 +1,125 @@
+'use strict'
+
+// These tables borrowed from `ansi`
+
+var prefix = '\x1b['
+
+exports.up = function up (num) {
+  return prefix + (num || '') + 'A'
+}
+
+exports.down = function down (num) {
+  return prefix + (num || '') + 'B'
+}
+
+exports.forward = function forward (num) {
+  return prefix + (num || '') + 'C'
+}
+
+exports.back = function back (num) {
+  return prefix + (num || '') + 'D'
+}
+
+exports.nextLine = function nextLine (num) {
+  return prefix + (num || '') + 'E'
+}
+
+exports.previousLine = function previousLine (num) {
+  return prefix + (num || '') + 'F'
+}
+
+exports.horizontalAbsolute = function horizontalAbsolute (num) {
+  if (num == null) throw new Error('horizontalAboslute requires a column to position to')
+  return prefix + num + 'G'
+}
+
+exports.eraseData = function eraseData () {
+  return prefix + 'J'
+}
+
+exports.eraseLine = function eraseLine () {
+  return prefix + 'K'
+}
+
+exports.goto = function (x, y) {
+  return prefix + y + ';' + x + 'H'
+}
+
+exports.gotoSOL = function () {
+  return '\r'
+}
+
+exports.beep = function () {
+  return '\x07'
+}
+
+exports.hideCursor = function hideCursor () {
+  return prefix + '?25l'
+}
+
+exports.showCursor = function showCursor () {
+  return prefix + '?25h'
+}
+
+var colors = {
+  reset: 0,
+// styles
+  bold: 1,
+  italic: 3,
+  underline: 4,
+  inverse: 7,
+// resets
+  stopBold: 22,
+  stopItalic: 23,
+  stopUnderline: 24,
+  stopInverse: 27,
+// colors
+  white: 37,
+  black: 30,
+  blue: 34,
+  cyan: 36,
+  green: 32,
+  magenta: 35,
+  red: 31,
+  yellow: 33,
+  bgWhite: 47,
+  bgBlack: 40,
+  bgBlue: 44,
+  bgCyan: 46,
+  bgGreen: 42,
+  bgMagenta: 45,
+  bgRed: 41,
+  bgYellow: 43,
+
+  grey: 90,
+  brightBlack: 90,
+  brightRed: 91,
+  brightGreen: 92,
+  brightYellow: 93,
+  brightBlue: 94,
+  brightMagenta: 95,
+  brightCyan: 96,
+  brightWhite: 97,
+
+  bgGrey: 100,
+  bgBrightBlack: 100,
+  bgBrightRed: 101,
+  bgBrightGreen: 102,
+  bgBrightYellow: 103,
+  bgBrightBlue: 104,
+  bgBrightMagenta: 105,
+  bgBrightCyan: 106,
+  bgBrightWhite: 107
+}
+
+exports.color = function color (colorWith) {
+  if (arguments.length !== 1 || !Array.isArray(colorWith)) {
+    colorWith = Array.prototype.slice.call(arguments)
+  }
+  return prefix + colorWith.map(colorNameToCode).join(';') + 'm'
+}
+
+function colorNameToCode (color) {
+  if (colors[color] != null) return colors[color]
+  throw new Error('Unknown color or style name: ' + color)
+}
diff --git a/server/node_modules/console-control-strings/package.json b/server/node_modules/console-control-strings/package.json
new file mode 100644
index 0000000..eb6c62a
--- /dev/null
+++ b/server/node_modules/console-control-strings/package.json
@@ -0,0 +1,27 @@
+{
+  "name": "console-control-strings",
+  "version": "1.1.0",
+  "description": "A library of cross-platform tested terminal/console command strings for doing things like color and cursor positioning.  This is a subset of both ansi and vt100.  All control codes included work on both Windows & Unix-like OSes, except where noted.",
+  "main": "index.js",
+  "directories": {
+    "test": "test"
+  },
+  "scripts": {
+    "test": "standard && tap test/*.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/iarna/console-control-strings"
+  },
+  "keywords": [],
+  "author": "Rebecca Turner <me@re-becca.org> (http://re-becca.org/)",
+  "license": "ISC",
+  "files": [
+    "LICENSE",
+    "index.js"
+  ],
+  "devDependencies": {
+    "standard": "^7.1.2",
+    "tap": "^5.7.2"
+  }
+}
diff --git a/server/node_modules/content-disposition/HISTORY.md b/server/node_modules/content-disposition/HISTORY.md
new file mode 100644
index 0000000..488effa
--- /dev/null
+++ b/server/node_modules/content-disposition/HISTORY.md
@@ -0,0 +1,60 @@
+0.5.4 / 2021-12-10
+==================
+
+  * deps: safe-buffer@5.2.1
+
+0.5.3 / 2018-12-17
+==================
+
+  * Use `safe-buffer` for improved Buffer API
+
+0.5.2 / 2016-12-08
+==================
+
+  * Fix `parse` to accept any linear whitespace character
+
+0.5.1 / 2016-01-17
+==================
+
+  * perf: enable strict mode
+
+0.5.0 / 2014-10-11
+==================
+
+  * Add `parse` function
+
+0.4.0 / 2014-09-21
+==================
+
+  * Expand non-Unicode `filename` to the full ISO-8859-1 charset
+
+0.3.0 / 2014-09-20
+==================
+
+  * Add `fallback` option
+  * Add `type` option
+
+0.2.0 / 2014-09-19
+==================
+
+  * Reduce ambiguity of file names with hex escape in buggy browsers
+
+0.1.2 / 2014-09-19
+==================
+
+  * Fix periodic invalid Unicode filename header
+
+0.1.1 / 2014-09-19
+==================
+
+  * Fix invalid characters appearing in `filename*` parameter
+
+0.1.0 / 2014-09-18
+==================
+
+  * Make the `filename` argument optional
+
+0.0.0 / 2014-09-18
+==================
+
+  * Initial release
diff --git a/server/node_modules/content-disposition/LICENSE b/server/node_modules/content-disposition/LICENSE
new file mode 100644
index 0000000..84441fb
--- /dev/null
+++ b/server/node_modules/content-disposition/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2014-2017 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/content-disposition/README.md b/server/node_modules/content-disposition/README.md
new file mode 100644
index 0000000..3a0bb05
--- /dev/null
+++ b/server/node_modules/content-disposition/README.md
@@ -0,0 +1,142 @@
+# content-disposition
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][github-actions-ci-image]][github-actions-ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Create and parse HTTP `Content-Disposition` header
+
+## Installation
+
+```sh
+$ npm install content-disposition
+```
+
+## API
+
+```js
+var contentDisposition = require('content-disposition')
+```
+
+### contentDisposition(filename, options)
+
+Create an attachment `Content-Disposition` header value using the given file name,
+if supplied. The `filename` is optional and if no file name is desired, but you
+want to specify `options`, set `filename` to `undefined`.
+
+```js
+res.setHeader('Content-Disposition', contentDisposition('∫ maths.pdf'))
+```
+
+**note** HTTP headers are of the ISO-8859-1 character set. If you are writing this
+header through a means different from `setHeader` in Node.js, you'll want to specify
+the `'binary'` encoding in Node.js.
+
+#### Options
+
+`contentDisposition` accepts these properties in the options object.
+
+##### fallback
+
+If the `filename` option is outside ISO-8859-1, then the file name is actually
+stored in a supplemental field for clients that support Unicode file names and
+a ISO-8859-1 version of the file name is automatically generated.
+
+This specifies the ISO-8859-1 file name to override the automatic generation or
+disables the generation all together, defaults to `true`.
+
+  - A string will specify the ISO-8859-1 file name to use in place of automatic
+    generation.
+  - `false` will disable including a ISO-8859-1 file name and only include the
+    Unicode version (unless the file name is already ISO-8859-1).
+  - `true` will enable automatic generation if the file name is outside ISO-8859-1.
+
+If the `filename` option is ISO-8859-1 and this option is specified and has a
+different value, then the `filename` option is encoded in the extended field
+and this set as the fallback field, even though they are both ISO-8859-1.
+
+##### type
+
+Specifies the disposition type, defaults to `"attachment"`. This can also be
+`"inline"`, or any other value (all values except inline are treated like
+`attachment`, but can convey additional information if both parties agree to
+it). The type is normalized to lower-case.
+
+### contentDisposition.parse(string)
+
+```js
+var disposition = contentDisposition.parse('attachment; filename="EURO rates.txt"; filename*=UTF-8\'\'%e2%82%ac%20rates.txt')
+```
+
+Parse a `Content-Disposition` header string. This automatically handles extended
+("Unicode") parameters by decoding them and providing them under the standard
+parameter name. This will return an object with the following properties (examples
+are shown for the string `'attachment; filename="EURO rates.txt"; filename*=UTF-8\'\'%e2%82%ac%20rates.txt'`):
+
+ - `type`: The disposition type (always lower case). Example: `'attachment'`
+
+ - `parameters`: An object of the parameters in the disposition (name of parameter
+   always lower case and extended versions replace non-extended versions). Example:
+   `{filename: "€ rates.txt"}`
+
+## Examples
+
+### Send a file for download
+
+```js
+var contentDisposition = require('content-disposition')
+var destroy = require('destroy')
+var fs = require('fs')
+var http = require('http')
+var onFinished = require('on-finished')
+
+var filePath = '/path/to/public/plans.pdf'
+
+http.createServer(function onRequest (req, res) {
+  // set headers
+  res.setHeader('Content-Type', 'application/pdf')
+  res.setHeader('Content-Disposition', contentDisposition(filePath))
+
+  // send file
+  var stream = fs.createReadStream(filePath)
+  stream.pipe(res)
+  onFinished(res, function () {
+    destroy(stream)
+  })
+})
+```
+
+## Testing
+
+```sh
+$ npm test
+```
+
+## References
+
+- [RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1][rfc-2616]
+- [RFC 5987: Character Set and Language Encoding for Hypertext Transfer Protocol (HTTP) Header Field Parameters][rfc-5987]
+- [RFC 6266: Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP)][rfc-6266]
+- [Test Cases for HTTP Content-Disposition header field (RFC 6266) and the Encodings defined in RFCs 2047, 2231 and 5987][tc-2231]
+
+[rfc-2616]: https://tools.ietf.org/html/rfc2616
+[rfc-5987]: https://tools.ietf.org/html/rfc5987
+[rfc-6266]: https://tools.ietf.org/html/rfc6266
+[tc-2231]: http://greenbytes.de/tech/tc2231/
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/content-disposition.svg
+[npm-url]: https://npmjs.org/package/content-disposition
+[node-version-image]: https://img.shields.io/node/v/content-disposition.svg
+[node-version-url]: https://nodejs.org/en/download
+[coveralls-image]: https://img.shields.io/coveralls/jshttp/content-disposition.svg
+[coveralls-url]: https://coveralls.io/r/jshttp/content-disposition?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/content-disposition.svg
+[downloads-url]: https://npmjs.org/package/content-disposition
+[github-actions-ci-image]: https://img.shields.io/github/workflow/status/jshttp/content-disposition/ci/master?label=ci
+[github-actions-ci-url]: https://github.com/jshttp/content-disposition?query=workflow%3Aci
diff --git a/server/node_modules/content-disposition/index.js b/server/node_modules/content-disposition/index.js
new file mode 100644
index 0000000..ecec899
--- /dev/null
+++ b/server/node_modules/content-disposition/index.js
@@ -0,0 +1,458 @@
+/*!
+ * content-disposition
+ * Copyright(c) 2014-2017 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = contentDisposition
+module.exports.parse = parse
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var basename = require('path').basename
+var Buffer = require('safe-buffer').Buffer
+
+/**
+ * RegExp to match non attr-char, *after* encodeURIComponent (i.e. not including "%")
+ * @private
+ */
+
+var ENCODE_URL_ATTR_CHAR_REGEXP = /[\x00-\x20"'()*,/:;<=>?@[\\\]{}\x7f]/g // eslint-disable-line no-control-regex
+
+/**
+ * RegExp to match percent encoding escape.
+ * @private
+ */
+
+var HEX_ESCAPE_REGEXP = /%[0-9A-Fa-f]{2}/
+var HEX_ESCAPE_REPLACE_REGEXP = /%([0-9A-Fa-f]{2})/g
+
+/**
+ * RegExp to match non-latin1 characters.
+ * @private
+ */
+
+var NON_LATIN1_REGEXP = /[^\x20-\x7e\xa0-\xff]/g
+
+/**
+ * RegExp to match quoted-pair in RFC 2616
+ *
+ * quoted-pair = "\" CHAR
+ * CHAR        = <any US-ASCII character (octets 0 - 127)>
+ * @private
+ */
+
+var QESC_REGEXP = /\\([\u0000-\u007f])/g // eslint-disable-line no-control-regex
+
+/**
+ * RegExp to match chars that must be quoted-pair in RFC 2616
+ * @private
+ */
+
+var QUOTE_REGEXP = /([\\"])/g
+
+/**
+ * RegExp for various RFC 2616 grammar
+ *
+ * parameter     = token "=" ( token | quoted-string )
+ * token         = 1*<any CHAR except CTLs or separators>
+ * separators    = "(" | ")" | "<" | ">" | "@"
+ *               | "," | ";" | ":" | "\" | <">
+ *               | "/" | "[" | "]" | "?" | "="
+ *               | "{" | "}" | SP | HT
+ * quoted-string = ( <"> *(qdtext | quoted-pair ) <"> )
+ * qdtext        = <any TEXT except <">>
+ * quoted-pair   = "\" CHAR
+ * CHAR          = <any US-ASCII character (octets 0 - 127)>
+ * TEXT          = <any OCTET except CTLs, but including LWS>
+ * LWS           = [CRLF] 1*( SP | HT )
+ * CRLF          = CR LF
+ * CR            = <US-ASCII CR, carriage return (13)>
+ * LF            = <US-ASCII LF, linefeed (10)>
+ * SP            = <US-ASCII SP, space (32)>
+ * HT            = <US-ASCII HT, horizontal-tab (9)>
+ * CTL           = <any US-ASCII control character (octets 0 - 31) and DEL (127)>
+ * OCTET         = <any 8-bit sequence of data>
+ * @private
+ */
+
+var PARAM_REGEXP = /;[\x09\x20]*([!#$%&'*+.0-9A-Z^_`a-z|~-]+)[\x09\x20]*=[\x09\x20]*("(?:[\x20!\x23-\x5b\x5d-\x7e\x80-\xff]|\\[\x20-\x7e])*"|[!#$%&'*+.0-9A-Z^_`a-z|~-]+)[\x09\x20]*/g // eslint-disable-line no-control-regex
+var TEXT_REGEXP = /^[\x20-\x7e\x80-\xff]+$/
+var TOKEN_REGEXP = /^[!#$%&'*+.0-9A-Z^_`a-z|~-]+$/
+
+/**
+ * RegExp for various RFC 5987 grammar
+ *
+ * ext-value     = charset  "'" [ language ] "'" value-chars
+ * charset       = "UTF-8" / "ISO-8859-1" / mime-charset
+ * mime-charset  = 1*mime-charsetc
+ * mime-charsetc = ALPHA / DIGIT
+ *               / "!" / "#" / "$" / "%" / "&"
+ *               / "+" / "-" / "^" / "_" / "`"
+ *               / "{" / "}" / "~"
+ * language      = ( 2*3ALPHA [ extlang ] )
+ *               / 4ALPHA
+ *               / 5*8ALPHA
+ * extlang       = *3( "-" 3ALPHA )
+ * value-chars   = *( pct-encoded / attr-char )
+ * pct-encoded   = "%" HEXDIG HEXDIG
+ * attr-char     = ALPHA / DIGIT
+ *               / "!" / "#" / "$" / "&" / "+" / "-" / "."
+ *               / "^" / "_" / "`" / "|" / "~"
+ * @private
+ */
+
+var EXT_VALUE_REGEXP = /^([A-Za-z0-9!#$%&+\-^_`{}~]+)'(?:[A-Za-z]{2,3}(?:-[A-Za-z]{3}){0,3}|[A-Za-z]{4,8}|)'((?:%[0-9A-Fa-f]{2}|[A-Za-z0-9!#$&+.^_`|~-])+)$/
+
+/**
+ * RegExp for various RFC 6266 grammar
+ *
+ * disposition-type = "inline" | "attachment" | disp-ext-type
+ * disp-ext-type    = token
+ * disposition-parm = filename-parm | disp-ext-parm
+ * filename-parm    = "filename" "=" value
+ *                  | "filename*" "=" ext-value
+ * disp-ext-parm    = token "=" value
+ *                  | ext-token "=" ext-value
+ * ext-token        = <the characters in token, followed by "*">
+ * @private
+ */
+
+var DISPOSITION_TYPE_REGEXP = /^([!#$%&'*+.0-9A-Z^_`a-z|~-]+)[\x09\x20]*(?:$|;)/ // eslint-disable-line no-control-regex
+
+/**
+ * Create an attachment Content-Disposition header.
+ *
+ * @param {string} [filename]
+ * @param {object} [options]
+ * @param {string} [options.type=attachment]
+ * @param {string|boolean} [options.fallback=true]
+ * @return {string}
+ * @public
+ */
+
+function contentDisposition (filename, options) {
+  var opts = options || {}
+
+  // get type
+  var type = opts.type || 'attachment'
+
+  // get parameters
+  var params = createparams(filename, opts.fallback)
+
+  // format into string
+  return format(new ContentDisposition(type, params))
+}
+
+/**
+ * Create parameters object from filename and fallback.
+ *
+ * @param {string} [filename]
+ * @param {string|boolean} [fallback=true]
+ * @return {object}
+ * @private
+ */
+
+function createparams (filename, fallback) {
+  if (filename === undefined) {
+    return
+  }
+
+  var params = {}
+
+  if (typeof filename !== 'string') {
+    throw new TypeError('filename must be a string')
+  }
+
+  // fallback defaults to true
+  if (fallback === undefined) {
+    fallback = true
+  }
+
+  if (typeof fallback !== 'string' && typeof fallback !== 'boolean') {
+    throw new TypeError('fallback must be a string or boolean')
+  }
+
+  if (typeof fallback === 'string' && NON_LATIN1_REGEXP.test(fallback)) {
+    throw new TypeError('fallback must be ISO-8859-1 string')
+  }
+
+  // restrict to file base name
+  var name = basename(filename)
+
+  // determine if name is suitable for quoted string
+  var isQuotedString = TEXT_REGEXP.test(name)
+
+  // generate fallback name
+  var fallbackName = typeof fallback !== 'string'
+    ? fallback && getlatin1(name)
+    : basename(fallback)
+  var hasFallback = typeof fallbackName === 'string' && fallbackName !== name
+
+  // set extended filename parameter
+  if (hasFallback || !isQuotedString || HEX_ESCAPE_REGEXP.test(name)) {
+    params['filename*'] = name
+  }
+
+  // set filename parameter
+  if (isQuotedString || hasFallback) {
+    params.filename = hasFallback
+      ? fallbackName
+      : name
+  }
+
+  return params
+}
+
+/**
+ * Format object to Content-Disposition header.
+ *
+ * @param {object} obj
+ * @param {string} obj.type
+ * @param {object} [obj.parameters]
+ * @return {string}
+ * @private
+ */
+
+function format (obj) {
+  var parameters = obj.parameters
+  var type = obj.type
+
+  if (!type || typeof type !== 'string' || !TOKEN_REGEXP.test(type)) {
+    throw new TypeError('invalid type')
+  }
+
+  // start with normalized type
+  var string = String(type).toLowerCase()
+
+  // append parameters
+  if (parameters && typeof parameters === 'object') {
+    var param
+    var params = Object.keys(parameters).sort()
+
+    for (var i = 0; i < params.length; i++) {
+      param = params[i]
+
+      var val = param.substr(-1) === '*'
+        ? ustring(parameters[param])
+        : qstring(parameters[param])
+
+      string += '; ' + param + '=' + val
+    }
+  }
+
+  return string
+}
+
+/**
+ * Decode a RFC 5987 field value (gracefully).
+ *
+ * @param {string} str
+ * @return {string}
+ * @private
+ */
+
+function decodefield (str) {
+  var match = EXT_VALUE_REGEXP.exec(str)
+
+  if (!match) {
+    throw new TypeError('invalid extended field value')
+  }
+
+  var charset = match[1].toLowerCase()
+  var encoded = match[2]
+  var value
+
+  // to binary string
+  var binary = encoded.replace(HEX_ESCAPE_REPLACE_REGEXP, pdecode)
+
+  switch (charset) {
+    case 'iso-8859-1':
+      value = getlatin1(binary)
+      break
+    case 'utf-8':
+      value = Buffer.from(binary, 'binary').toString('utf8')
+      break
+    default:
+      throw new TypeError('unsupported charset in extended field')
+  }
+
+  return value
+}
+
+/**
+ * Get ISO-8859-1 version of string.
+ *
+ * @param {string} val
+ * @return {string}
+ * @private
+ */
+
+function getlatin1 (val) {
+  // simple Unicode -> ISO-8859-1 transformation
+  return String(val).replace(NON_LATIN1_REGEXP, '?')
+}
+
+/**
+ * Parse Content-Disposition header string.
+ *
+ * @param {string} string
+ * @return {object}
+ * @public
+ */
+
+function parse (string) {
+  if (!string || typeof string !== 'string') {
+    throw new TypeError('argument string is required')
+  }
+
+  var match = DISPOSITION_TYPE_REGEXP.exec(string)
+
+  if (!match) {
+    throw new TypeError('invalid type format')
+  }
+
+  // normalize type
+  var index = match[0].length
+  var type = match[1].toLowerCase()
+
+  var key
+  var names = []
+  var params = {}
+  var value
+
+  // calculate index to start at
+  index = PARAM_REGEXP.lastIndex = match[0].substr(-1) === ';'
+    ? index - 1
+    : index
+
+  // match parameters
+  while ((match = PARAM_REGEXP.exec(string))) {
+    if (match.index !== index) {
+      throw new TypeError('invalid parameter format')
+    }
+
+    index += match[0].length
+    key = match[1].toLowerCase()
+    value = match[2]
+
+    if (names.indexOf(key) !== -1) {
+      throw new TypeError('invalid duplicate parameter')
+    }
+
+    names.push(key)
+
+    if (key.indexOf('*') + 1 === key.length) {
+      // decode extended value
+      key = key.slice(0, -1)
+      value = decodefield(value)
+
+      // overwrite existing value
+      params[key] = value
+      continue
+    }
+
+    if (typeof params[key] === 'string') {
+      continue
+    }
+
+    if (value[0] === '"') {
+      // remove quotes and escapes
+      value = value
+        .substr(1, value.length - 2)
+        .replace(QESC_REGEXP, '$1')
+    }
+
+    params[key] = value
+  }
+
+  if (index !== -1 && index !== string.length) {
+    throw new TypeError('invalid parameter format')
+  }
+
+  return new ContentDisposition(type, params)
+}
+
+/**
+ * Percent decode a single character.
+ *
+ * @param {string} str
+ * @param {string} hex
+ * @return {string}
+ * @private
+ */
+
+function pdecode (str, hex) {
+  return String.fromCharCode(parseInt(hex, 16))
+}
+
+/**
+ * Percent encode a single character.
+ *
+ * @param {string} char
+ * @return {string}
+ * @private
+ */
+
+function pencode (char) {
+  return '%' + String(char)
+    .charCodeAt(0)
+    .toString(16)
+    .toUpperCase()
+}
+
+/**
+ * Quote a string for HTTP.
+ *
+ * @param {string} val
+ * @return {string}
+ * @private
+ */
+
+function qstring (val) {
+  var str = String(val)
+
+  return '"' + str.replace(QUOTE_REGEXP, '\\$1') + '"'
+}
+
+/**
+ * Encode a Unicode string for HTTP (RFC 5987).
+ *
+ * @param {string} val
+ * @return {string}
+ * @private
+ */
+
+function ustring (val) {
+  var str = String(val)
+
+  // percent encode as UTF-8
+  var encoded = encodeURIComponent(str)
+    .replace(ENCODE_URL_ATTR_CHAR_REGEXP, pencode)
+
+  return 'UTF-8\'\'' + encoded
+}
+
+/**
+ * Class for parsed Content-Disposition header for v8 optimization
+ *
+ * @public
+ * @param {string} type
+ * @param {object} parameters
+ * @constructor
+ */
+
+function ContentDisposition (type, parameters) {
+  this.type = type
+  this.parameters = parameters
+}
diff --git a/server/node_modules/content-disposition/package.json b/server/node_modules/content-disposition/package.json
new file mode 100644
index 0000000..43c70ce
--- /dev/null
+++ b/server/node_modules/content-disposition/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "content-disposition",
+  "description": "Create and parse Content-Disposition header",
+  "version": "0.5.4",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "keywords": [
+    "content-disposition",
+    "http",
+    "rfc6266",
+    "res"
+  ],
+  "repository": "jshttp/content-disposition",
+  "dependencies": {
+    "safe-buffer": "5.2.1"
+  },
+  "devDependencies": {
+    "deep-equal": "1.0.1",
+    "eslint": "7.32.0",
+    "eslint-config-standard": "13.0.1",
+    "eslint-plugin-import": "2.25.3",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "5.2.0",
+    "eslint-plugin-standard": "4.1.0",
+    "istanbul": "0.4.5",
+    "mocha": "9.1.3"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-ci": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/"
+  }
+}
diff --git a/server/node_modules/content-type/HISTORY.md b/server/node_modules/content-type/HISTORY.md
new file mode 100644
index 0000000..4583671
--- /dev/null
+++ b/server/node_modules/content-type/HISTORY.md
@@ -0,0 +1,29 @@
+1.0.5 / 2023-01-29
+==================
+
+  * perf: skip value escaping when unnecessary
+
+1.0.4 / 2017-09-11
+==================
+
+  * perf: skip parameter parsing when no parameters
+
+1.0.3 / 2017-09-10
+==================
+
+  * perf: remove argument reassignment
+
+1.0.2 / 2016-05-09
+==================
+
+  * perf: enable strict mode
+
+1.0.1 / 2015-02-13
+==================
+
+  * Improve missing `Content-Type` header error message
+
+1.0.0 / 2015-02-01
+==================
+
+  * Initial implementation, derived from `media-typer@0.3.0`
diff --git a/server/node_modules/content-type/LICENSE b/server/node_modules/content-type/LICENSE
new file mode 100644
index 0000000..34b1a2d
--- /dev/null
+++ b/server/node_modules/content-type/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2015 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/content-type/README.md b/server/node_modules/content-type/README.md
new file mode 100644
index 0000000..c1a922a
--- /dev/null
+++ b/server/node_modules/content-type/README.md
@@ -0,0 +1,94 @@
+# content-type
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][ci-image]][ci-url]
+[![Coverage Status][coveralls-image]][coveralls-url]
+
+Create and parse HTTP Content-Type header according to RFC 7231
+
+## Installation
+
+```sh
+$ npm install content-type
+```
+
+## API
+
+```js
+var contentType = require('content-type')
+```
+
+### contentType.parse(string)
+
+```js
+var obj = contentType.parse('image/svg+xml; charset=utf-8')
+```
+
+Parse a `Content-Type` header. This will return an object with the following
+properties (examples are shown for the string `'image/svg+xml; charset=utf-8'`):
+
+ - `type`: The media type (the type and subtype, always lower case).
+   Example: `'image/svg+xml'`
+
+ - `parameters`: An object of the parameters in the media type (name of parameter
+   always lower case). Example: `{charset: 'utf-8'}`
+
+Throws a `TypeError` if the string is missing or invalid.
+
+### contentType.parse(req)
+
+```js
+var obj = contentType.parse(req)
+```
+
+Parse the `Content-Type` header from the given `req`. Short-cut for
+`contentType.parse(req.headers['content-type'])`.
+
+Throws a `TypeError` if the `Content-Type` header is missing or invalid.
+
+### contentType.parse(res)
+
+```js
+var obj = contentType.parse(res)
+```
+
+Parse the `Content-Type` header set on the given `res`. Short-cut for
+`contentType.parse(res.getHeader('content-type'))`.
+
+Throws a `TypeError` if the `Content-Type` header is missing or invalid.
+
+### contentType.format(obj)
+
+```js
+var str = contentType.format({
+  type: 'image/svg+xml',
+  parameters: { charset: 'utf-8' }
+})
+```
+
+Format an object into a `Content-Type` header. This will return a string of the
+content type for the given object with the following properties (examples are
+shown that produce the string `'image/svg+xml; charset=utf-8'`):
+
+ - `type`: The media type (will be lower-cased). Example: `'image/svg+xml'`
+
+ - `parameters`: An object of the parameters in the media type (name of the
+   parameter will be lower-cased). Example: `{charset: 'utf-8'}`
+
+Throws a `TypeError` if the object contains an invalid type or parameter names.
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/jshttp/content-type/master?label=ci
+[ci-url]: https://github.com/jshttp/content-type/actions/workflows/ci.yml
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/content-type/master
+[coveralls-url]: https://coveralls.io/r/jshttp/content-type?branch=master
+[node-image]: https://badgen.net/npm/node/content-type
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/content-type
+[npm-url]: https://npmjs.org/package/content-type
+[npm-version-image]: https://badgen.net/npm/v/content-type
diff --git a/server/node_modules/content-type/index.js b/server/node_modules/content-type/index.js
new file mode 100644
index 0000000..41840e7
--- /dev/null
+++ b/server/node_modules/content-type/index.js
@@ -0,0 +1,225 @@
+/*!
+ * content-type
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * RegExp to match *( ";" parameter ) in RFC 7231 sec 3.1.1.1
+ *
+ * parameter     = token "=" ( token / quoted-string )
+ * token         = 1*tchar
+ * tchar         = "!" / "#" / "$" / "%" / "&" / "'" / "*"
+ *               / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
+ *               / DIGIT / ALPHA
+ *               ; any VCHAR, except delimiters
+ * quoted-string = DQUOTE *( qdtext / quoted-pair ) DQUOTE
+ * qdtext        = HTAB / SP / %x21 / %x23-5B / %x5D-7E / obs-text
+ * obs-text      = %x80-FF
+ * quoted-pair   = "\" ( HTAB / SP / VCHAR / obs-text )
+ */
+var PARAM_REGEXP = /; *([!#$%&'*+.^_`|~0-9A-Za-z-]+) *= *("(?:[\u000b\u0020\u0021\u0023-\u005b\u005d-\u007e\u0080-\u00ff]|\\[\u000b\u0020-\u00ff])*"|[!#$%&'*+.^_`|~0-9A-Za-z-]+) */g // eslint-disable-line no-control-regex
+var TEXT_REGEXP = /^[\u000b\u0020-\u007e\u0080-\u00ff]+$/ // eslint-disable-line no-control-regex
+var TOKEN_REGEXP = /^[!#$%&'*+.^_`|~0-9A-Za-z-]+$/
+
+/**
+ * RegExp to match quoted-pair in RFC 7230 sec 3.2.6
+ *
+ * quoted-pair = "\" ( HTAB / SP / VCHAR / obs-text )
+ * obs-text    = %x80-FF
+ */
+var QESC_REGEXP = /\\([\u000b\u0020-\u00ff])/g // eslint-disable-line no-control-regex
+
+/**
+ * RegExp to match chars that must be quoted-pair in RFC 7230 sec 3.2.6
+ */
+var QUOTE_REGEXP = /([\\"])/g
+
+/**
+ * RegExp to match type in RFC 7231 sec 3.1.1.1
+ *
+ * media-type = type "/" subtype
+ * type       = token
+ * subtype    = token
+ */
+var TYPE_REGEXP = /^[!#$%&'*+.^_`|~0-9A-Za-z-]+\/[!#$%&'*+.^_`|~0-9A-Za-z-]+$/
+
+/**
+ * Module exports.
+ * @public
+ */
+
+exports.format = format
+exports.parse = parse
+
+/**
+ * Format object to media type.
+ *
+ * @param {object} obj
+ * @return {string}
+ * @public
+ */
+
+function format (obj) {
+  if (!obj || typeof obj !== 'object') {
+    throw new TypeError('argument obj is required')
+  }
+
+  var parameters = obj.parameters
+  var type = obj.type
+
+  if (!type || !TYPE_REGEXP.test(type)) {
+    throw new TypeError('invalid type')
+  }
+
+  var string = type
+
+  // append parameters
+  if (parameters && typeof parameters === 'object') {
+    var param
+    var params = Object.keys(parameters).sort()
+
+    for (var i = 0; i < params.length; i++) {
+      param = params[i]
+
+      if (!TOKEN_REGEXP.test(param)) {
+        throw new TypeError('invalid parameter name')
+      }
+
+      string += '; ' + param + '=' + qstring(parameters[param])
+    }
+  }
+
+  return string
+}
+
+/**
+ * Parse media type to object.
+ *
+ * @param {string|object} string
+ * @return {Object}
+ * @public
+ */
+
+function parse (string) {
+  if (!string) {
+    throw new TypeError('argument string is required')
+  }
+
+  // support req/res-like objects as argument
+  var header = typeof string === 'object'
+    ? getcontenttype(string)
+    : string
+
+  if (typeof header !== 'string') {
+    throw new TypeError('argument string is required to be a string')
+  }
+
+  var index = header.indexOf(';')
+  var type = index !== -1
+    ? header.slice(0, index).trim()
+    : header.trim()
+
+  if (!TYPE_REGEXP.test(type)) {
+    throw new TypeError('invalid media type')
+  }
+
+  var obj = new ContentType(type.toLowerCase())
+
+  // parse parameters
+  if (index !== -1) {
+    var key
+    var match
+    var value
+
+    PARAM_REGEXP.lastIndex = index
+
+    while ((match = PARAM_REGEXP.exec(header))) {
+      if (match.index !== index) {
+        throw new TypeError('invalid parameter format')
+      }
+
+      index += match[0].length
+      key = match[1].toLowerCase()
+      value = match[2]
+
+      if (value.charCodeAt(0) === 0x22 /* " */) {
+        // remove quotes
+        value = value.slice(1, -1)
+
+        // remove escapes
+        if (value.indexOf('\\') !== -1) {
+          value = value.replace(QESC_REGEXP, '$1')
+        }
+      }
+
+      obj.parameters[key] = value
+    }
+
+    if (index !== header.length) {
+      throw new TypeError('invalid parameter format')
+    }
+  }
+
+  return obj
+}
+
+/**
+ * Get content-type from req/res objects.
+ *
+ * @param {object}
+ * @return {Object}
+ * @private
+ */
+
+function getcontenttype (obj) {
+  var header
+
+  if (typeof obj.getHeader === 'function') {
+    // res-like
+    header = obj.getHeader('content-type')
+  } else if (typeof obj.headers === 'object') {
+    // req-like
+    header = obj.headers && obj.headers['content-type']
+  }
+
+  if (typeof header !== 'string') {
+    throw new TypeError('content-type header is missing from object')
+  }
+
+  return header
+}
+
+/**
+ * Quote a string if necessary.
+ *
+ * @param {string} val
+ * @return {string}
+ * @private
+ */
+
+function qstring (val) {
+  var str = String(val)
+
+  // no need to quote tokens
+  if (TOKEN_REGEXP.test(str)) {
+    return str
+  }
+
+  if (str.length > 0 && !TEXT_REGEXP.test(str)) {
+    throw new TypeError('invalid parameter value')
+  }
+
+  return '"' + str.replace(QUOTE_REGEXP, '\\$1') + '"'
+}
+
+/**
+ * Class to represent a content type.
+ * @private
+ */
+function ContentType (type) {
+  this.parameters = Object.create(null)
+  this.type = type
+}
diff --git a/server/node_modules/content-type/package.json b/server/node_modules/content-type/package.json
new file mode 100644
index 0000000..9db19f6
--- /dev/null
+++ b/server/node_modules/content-type/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "content-type",
+  "description": "Create and parse HTTP Content-Type header",
+  "version": "1.0.5",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "keywords": [
+    "content-type",
+    "http",
+    "req",
+    "res",
+    "rfc7231"
+  ],
+  "repository": "jshttp/content-type",
+  "devDependencies": {
+    "deep-equal": "1.0.1",
+    "eslint": "8.32.0",
+    "eslint-config-standard": "15.0.1",
+    "eslint-plugin-import": "2.27.5",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "6.1.1",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "10.2.0",
+    "nyc": "15.1.0"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --check-leaks --bail test/",
+    "test-ci": "nyc --reporter=lcovonly --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  }
+}
diff --git a/server/node_modules/cookie-signature/History.md b/server/node_modules/cookie-signature/History.md
new file mode 100644
index 0000000..bcf8cc9
--- /dev/null
+++ b/server/node_modules/cookie-signature/History.md
@@ -0,0 +1,42 @@
+1.0.7 / 2023-04-12
+==================
+
+* backport the buffer support from the 1.2.x release branch (thanks @FadhiliNjagi!)
+
+1.0.6 / 2015-02-03
+==================
+
+* use `npm test` instead of `make test` to run tests
+* clearer assertion messages when checking input
+
+1.0.5 / 2014-09-05
+==================
+
+* add license to package.json
+
+1.0.4 / 2014-06-25
+==================
+
+ * corrected avoidance of timing attacks (thanks @tenbits!)
+
+1.0.3 / 2014-01-28
+==================
+
+ * [incorrect] fix for timing attacks
+
+1.0.2 / 2014-01-28
+==================
+
+ * fix missing repository warning
+ * fix typo in test
+
+1.0.1 / 2013-04-15
+==================
+
+  * Revert "Changed underlying HMAC algo. to sha512."
+  * Revert "Fix for timing attacks on MAC verification."
+
+0.0.1 / 2010-01-03
+==================
+
+  * Initial release
diff --git a/server/node_modules/cookie-signature/Readme.md b/server/node_modules/cookie-signature/Readme.md
new file mode 100644
index 0000000..2559e84
--- /dev/null
+++ b/server/node_modules/cookie-signature/Readme.md
@@ -0,0 +1,42 @@
+
+# cookie-signature
+
+  Sign and unsign cookies.
+
+## Example
+
+```js
+var cookie = require('cookie-signature');
+
+var val = cookie.sign('hello', 'tobiiscool');
+val.should.equal('hello.DGDUkGlIkCzPz+C0B064FNgHdEjox7ch8tOBGslZ5QI');
+
+var val = cookie.sign('hello', 'tobiiscool');
+cookie.unsign(val, 'tobiiscool').should.equal('hello');
+cookie.unsign(val, 'luna').should.be.false;
+```
+
+## License 
+
+(The MIT License)
+
+Copyright (c) 2012 LearnBoost <tj@learnboost.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/cookie-signature/index.js b/server/node_modules/cookie-signature/index.js
new file mode 100644
index 0000000..336d487
--- /dev/null
+++ b/server/node_modules/cookie-signature/index.js
@@ -0,0 +1,51 @@
+/**
+ * Module dependencies.
+ */
+
+var crypto = require('crypto');
+
+/**
+ * Sign the given `val` with `secret`.
+ *
+ * @param {String} val
+ * @param {String|NodeJS.ArrayBufferView|crypto.KeyObject} secret
+ * @return {String}
+ * @api private
+ */
+
+exports.sign = function(val, secret){
+  if ('string' !== typeof val) throw new TypeError("Cookie value must be provided as a string.");
+  if (null == secret) throw new TypeError("Secret key must be provided.");
+  return val + '.' + crypto
+    .createHmac('sha256', secret)
+    .update(val)
+    .digest('base64')
+    .replace(/\=+$/, '');
+};
+
+/**
+ * Unsign and decode the given `val` with `secret`,
+ * returning `false` if the signature is invalid.
+ *
+ * @param {String} val
+ * @param {String|NodeJS.ArrayBufferView|crypto.KeyObject} secret
+ * @return {String|Boolean}
+ * @api private
+ */
+
+exports.unsign = function(val, secret){
+  if ('string' !== typeof val) throw new TypeError("Signed cookie string must be provided.");
+  if (null == secret) throw new TypeError("Secret key must be provided.");
+  var str = val.slice(0, val.lastIndexOf('.'))
+    , mac = exports.sign(str, secret);
+  
+  return sha1(mac) == sha1(val) ? str : false;
+};
+
+/**
+ * Private
+ */
+
+function sha1(str){
+  return crypto.createHash('sha1').update(str).digest('hex');
+}
diff --git a/server/node_modules/cookie-signature/package.json b/server/node_modules/cookie-signature/package.json
new file mode 100644
index 0000000..738487b
--- /dev/null
+++ b/server/node_modules/cookie-signature/package.json
@@ -0,0 +1,18 @@
+{
+  "name": "cookie-signature",
+  "version": "1.0.7",
+  "description": "Sign and unsign cookies",
+  "keywords": ["cookie", "sign", "unsign"],
+  "author": "TJ Holowaychuk <tj@learnboost.com>",
+  "license": "MIT",
+  "repository": { "type": "git", "url": "https://github.com/visionmedia/node-cookie-signature.git"},
+  "dependencies": {},
+  "devDependencies": {
+    "mocha": "*",
+    "should": "*"
+  },
+  "scripts": {
+    "test": "mocha --require should --reporter spec"
+  },
+  "main": "index"
+}
\ No newline at end of file
diff --git a/server/node_modules/cookie/LICENSE b/server/node_modules/cookie/LICENSE
new file mode 100644
index 0000000..058b6b4
--- /dev/null
+++ b/server/node_modules/cookie/LICENSE
@@ -0,0 +1,24 @@
+(The MIT License)
+
+Copyright (c) 2012-2014 Roman Shtylman <shtylman@gmail.com>
+Copyright (c) 2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/cookie/README.md b/server/node_modules/cookie/README.md
new file mode 100644
index 0000000..71fdac1
--- /dev/null
+++ b/server/node_modules/cookie/README.md
@@ -0,0 +1,317 @@
+# cookie
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][ci-image]][ci-url]
+[![Coverage Status][coveralls-image]][coveralls-url]
+
+Basic HTTP cookie parser and serializer for HTTP servers.
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install cookie
+```
+
+## API
+
+```js
+var cookie = require('cookie');
+```
+
+### cookie.parse(str, options)
+
+Parse an HTTP `Cookie` header string and returning an object of all cookie name-value pairs.
+The `str` argument is the string representing a `Cookie` header value and `options` is an
+optional object containing additional parsing options.
+
+```js
+var cookies = cookie.parse('foo=bar; equation=E%3Dmc%5E2');
+// { foo: 'bar', equation: 'E=mc^2' }
+```
+
+#### Options
+
+`cookie.parse` accepts these properties in the options object.
+
+##### decode
+
+Specifies a function that will be used to decode a cookie's value. Since the value of a cookie
+has a limited character set (and must be a simple string), this function can be used to decode
+a previously-encoded cookie value into a JavaScript string or other object.
+
+The default function is the global `decodeURIComponent`, which will decode any URL-encoded
+sequences into their byte representations.
+
+**note** if an error is thrown from this function, the original, non-decoded cookie value will
+be returned as the cookie's value.
+
+### cookie.serialize(name, value, options)
+
+Serialize a cookie name-value pair into a `Set-Cookie` header string. The `name` argument is the
+name for the cookie, the `value` argument is the value to set the cookie to, and the `options`
+argument is an optional object containing additional serialization options.
+
+```js
+var setCookie = cookie.serialize('foo', 'bar');
+// foo=bar
+```
+
+#### Options
+
+`cookie.serialize` accepts these properties in the options object.
+
+##### domain
+
+Specifies the value for the [`Domain` `Set-Cookie` attribute][rfc-6265-5.2.3]. By default, no
+domain is set, and most clients will consider the cookie to apply to only the current domain.
+
+##### encode
+
+Specifies a function that will be used to encode a cookie's value. Since value of a cookie
+has a limited character set (and must be a simple string), this function can be used to encode
+a value into a string suited for a cookie's value.
+
+The default function is the global `encodeURIComponent`, which will encode a JavaScript string
+into UTF-8 byte sequences and then URL-encode any that fall outside of the cookie range.
+
+##### expires
+
+Specifies the `Date` object to be the value for the [`Expires` `Set-Cookie` attribute][rfc-6265-5.2.1].
+By default, no expiration is set, and most clients will consider this a "non-persistent cookie" and
+will delete it on a condition like exiting a web browser application.
+
+**note** the [cookie storage model specification][rfc-6265-5.3] states that if both `expires` and
+`maxAge` are set, then `maxAge` takes precedence, but it is possible not all clients by obey this,
+so if both are set, they should point to the same date and time.
+
+##### httpOnly
+
+Specifies the `boolean` value for the [`HttpOnly` `Set-Cookie` attribute][rfc-6265-5.2.6]. When truthy,
+the `HttpOnly` attribute is set, otherwise it is not. By default, the `HttpOnly` attribute is not set.
+
+**note** be careful when setting this to `true`, as compliant clients will not allow client-side
+JavaScript to see the cookie in `document.cookie`.
+
+##### maxAge
+
+Specifies the `number` (in seconds) to be the value for the [`Max-Age` `Set-Cookie` attribute][rfc-6265-5.2.2].
+The given number will be converted to an integer by rounding down. By default, no maximum age is set.
+
+**note** the [cookie storage model specification][rfc-6265-5.3] states that if both `expires` and
+`maxAge` are set, then `maxAge` takes precedence, but it is possible not all clients by obey this,
+so if both are set, they should point to the same date and time.
+
+##### partitioned
+
+Specifies the `boolean` value for the [`Partitioned` `Set-Cookie`](rfc-cutler-httpbis-partitioned-cookies)
+attribute. When truthy, the `Partitioned` attribute is set, otherwise it is not. By default, the
+`Partitioned` attribute is not set.
+
+**note** This is an attribute that has not yet been fully standardized, and may change in the future.
+This also means many clients may ignore this attribute until they understand it.
+
+More information about can be found in [the proposal](https://github.com/privacycg/CHIPS).
+
+##### path
+
+Specifies the value for the [`Path` `Set-Cookie` attribute][rfc-6265-5.2.4]. By default, the path
+is considered the ["default path"][rfc-6265-5.1.4].
+
+##### priority
+
+Specifies the `string` to be the value for the [`Priority` `Set-Cookie` attribute][rfc-west-cookie-priority-00-4.1].
+
+  - `'low'` will set the `Priority` attribute to `Low`.
+  - `'medium'` will set the `Priority` attribute to `Medium`, the default priority when not set.
+  - `'high'` will set the `Priority` attribute to `High`.
+
+More information about the different priority levels can be found in
+[the specification][rfc-west-cookie-priority-00-4.1].
+
+**note** This is an attribute that has not yet been fully standardized, and may change in the future.
+This also means many clients may ignore this attribute until they understand it.
+
+##### sameSite
+
+Specifies the `boolean` or `string` to be the value for the [`SameSite` `Set-Cookie` attribute][rfc-6265bis-09-5.4.7].
+
+  - `true` will set the `SameSite` attribute to `Strict` for strict same site enforcement.
+  - `false` will not set the `SameSite` attribute.
+  - `'lax'` will set the `SameSite` attribute to `Lax` for lax same site enforcement.
+  - `'none'` will set the `SameSite` attribute to `None` for an explicit cross-site cookie.
+  - `'strict'` will set the `SameSite` attribute to `Strict` for strict same site enforcement.
+
+More information about the different enforcement levels can be found in
+[the specification][rfc-6265bis-09-5.4.7].
+
+**note** This is an attribute that has not yet been fully standardized, and may change in the future.
+This also means many clients may ignore this attribute until they understand it.
+
+##### secure
+
+Specifies the `boolean` value for the [`Secure` `Set-Cookie` attribute][rfc-6265-5.2.5]. When truthy,
+the `Secure` attribute is set, otherwise it is not. By default, the `Secure` attribute is not set.
+
+**note** be careful when setting this to `true`, as compliant clients will not send the cookie back to
+the server in the future if the browser does not have an HTTPS connection.
+
+## Example
+
+The following example uses this module in conjunction with the Node.js core HTTP server
+to prompt a user for their name and display it back on future visits.
+
+```js
+var cookie = require('cookie');
+var escapeHtml = require('escape-html');
+var http = require('http');
+var url = require('url');
+
+function onRequest(req, res) {
+  // Parse the query string
+  var query = url.parse(req.url, true, true).query;
+
+  if (query && query.name) {
+    // Set a new cookie with the name
+    res.setHeader('Set-Cookie', cookie.serialize('name', String(query.name), {
+      httpOnly: true,
+      maxAge: 60 * 60 * 24 * 7 // 1 week
+    }));
+
+    // Redirect back after setting cookie
+    res.statusCode = 302;
+    res.setHeader('Location', req.headers.referer || '/');
+    res.end();
+    return;
+  }
+
+  // Parse the cookies on the request
+  var cookies = cookie.parse(req.headers.cookie || '');
+
+  // Get the visitor name set in the cookie
+  var name = cookies.name;
+
+  res.setHeader('Content-Type', 'text/html; charset=UTF-8');
+
+  if (name) {
+    res.write('<p>Welcome back, <b>' + escapeHtml(name) + '</b>!</p>');
+  } else {
+    res.write('<p>Hello, new visitor!</p>');
+  }
+
+  res.write('<form method="GET">');
+  res.write('<input placeholder="enter your name" name="name"> <input type="submit" value="Set Name">');
+  res.end('</form>');
+}
+
+http.createServer(onRequest).listen(3000);
+```
+
+## Testing
+
+```sh
+$ npm test
+```
+
+## Benchmark
+
+```
+$ npm run bench
+
+> cookie@0.5.0 bench
+> node benchmark/index.js
+
+  node@18.18.2
+  acorn@8.10.0
+  ada@2.6.0
+  ares@1.19.1
+  brotli@1.0.9
+  cldr@43.1
+  icu@73.2
+  llhttp@6.0.11
+  modules@108
+  napi@9
+  nghttp2@1.57.0
+  nghttp3@0.7.0
+  ngtcp2@0.8.1
+  openssl@3.0.10+quic
+  simdutf@3.2.14
+  tz@2023c
+  undici@5.26.3
+  unicode@15.0
+  uv@1.44.2
+  uvwasi@0.0.18
+  v8@10.2.154.26-node.26
+  zlib@1.2.13.1-motley
+
+> node benchmark/parse-top.js
+
+  cookie.parse - top sites
+
+  14 tests completed.
+
+  parse accounts.google.com x 2,588,913 ops/sec ±0.74% (186 runs sampled)
+  parse apple.com           x 2,370,002 ops/sec ±0.69% (186 runs sampled)
+  parse cloudflare.com      x 2,213,102 ops/sec ±0.88% (188 runs sampled)
+  parse docs.google.com     x 2,194,157 ops/sec ±1.03% (184 runs sampled)
+  parse drive.google.com    x 2,265,084 ops/sec ±0.79% (187 runs sampled)
+  parse en.wikipedia.org    x   457,099 ops/sec ±0.81% (186 runs sampled)
+  parse linkedin.com        x   504,407 ops/sec ±0.89% (186 runs sampled)
+  parse maps.google.com     x 1,230,959 ops/sec ±0.98% (186 runs sampled)
+  parse microsoft.com       x   926,294 ops/sec ±0.88% (184 runs sampled)
+  parse play.google.com     x 2,311,338 ops/sec ±0.83% (185 runs sampled)
+  parse support.google.com  x 1,508,850 ops/sec ±0.86% (186 runs sampled)
+  parse www.google.com      x 1,022,582 ops/sec ±1.32% (182 runs sampled)
+  parse youtu.be            x   332,136 ops/sec ±1.02% (185 runs sampled)
+  parse youtube.com         x   323,833 ops/sec ±0.77% (183 runs sampled)
+
+> node benchmark/parse.js
+
+  cookie.parse - generic
+
+  6 tests completed.
+
+  simple      x 3,214,032 ops/sec ±1.61% (183 runs sampled)
+  decode      x   587,237 ops/sec ±1.16% (187 runs sampled)
+  unquote     x 2,954,618 ops/sec ±1.35% (183 runs sampled)
+  duplicates  x   857,008 ops/sec ±0.89% (187 runs sampled)
+  10 cookies  x   292,133 ops/sec ±0.89% (187 runs sampled)
+  100 cookies x    22,610 ops/sec ±0.68% (187 runs sampled)
+```
+
+## References
+
+- [RFC 6265: HTTP State Management Mechanism][rfc-6265]
+- [Same-site Cookies][rfc-6265bis-09-5.4.7]
+
+[rfc-cutler-httpbis-partitioned-cookies]: https://tools.ietf.org/html/draft-cutler-httpbis-partitioned-cookies/
+[rfc-west-cookie-priority-00-4.1]: https://tools.ietf.org/html/draft-west-cookie-priority-00#section-4.1
+[rfc-6265bis-09-5.4.7]: https://tools.ietf.org/html/draft-ietf-httpbis-rfc6265bis-09#section-5.4.7
+[rfc-6265]: https://tools.ietf.org/html/rfc6265
+[rfc-6265-5.1.4]: https://tools.ietf.org/html/rfc6265#section-5.1.4
+[rfc-6265-5.2.1]: https://tools.ietf.org/html/rfc6265#section-5.2.1
+[rfc-6265-5.2.2]: https://tools.ietf.org/html/rfc6265#section-5.2.2
+[rfc-6265-5.2.3]: https://tools.ietf.org/html/rfc6265#section-5.2.3
+[rfc-6265-5.2.4]: https://tools.ietf.org/html/rfc6265#section-5.2.4
+[rfc-6265-5.2.5]: https://tools.ietf.org/html/rfc6265#section-5.2.5
+[rfc-6265-5.2.6]: https://tools.ietf.org/html/rfc6265#section-5.2.6
+[rfc-6265-5.3]: https://tools.ietf.org/html/rfc6265#section-5.3
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/jshttp/cookie/master?label=ci
+[ci-url]: https://github.com/jshttp/cookie/actions/workflows/ci.yml
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/cookie/master
+[coveralls-url]: https://coveralls.io/r/jshttp/cookie?branch=master
+[node-image]: https://badgen.net/npm/node/cookie
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/cookie
+[npm-url]: https://npmjs.org/package/cookie
+[npm-version-image]: https://badgen.net/npm/v/cookie
diff --git a/server/node_modules/cookie/SECURITY.md b/server/node_modules/cookie/SECURITY.md
new file mode 100644
index 0000000..fd4a6c5
--- /dev/null
+++ b/server/node_modules/cookie/SECURITY.md
@@ -0,0 +1,25 @@
+# Security Policies and Procedures
+
+## Reporting a Bug
+
+The `cookie` team and community take all security bugs seriously. Thank
+you for improving the security of the project. We appreciate your efforts and
+responsible disclosure and will make every effort to acknowledge your
+contributions.
+
+Report security bugs by emailing the current owner(s) of `cookie`. This
+information can be found in the npm registry using the command
+`npm owner ls cookie`.
+If unsure or unable to get the information from the above, open an issue
+in the [project issue tracker](https://github.com/jshttp/cookie/issues)
+asking for the current contact information.
+
+To ensure the timely response to your report, please ensure that the entirety
+of the report is contained within the email body and not solely behind a web
+link or an attachment.
+
+At least one owner will acknowledge your email within 48 hours, and will send a
+more detailed response within 48 hours indicating the next steps in handling
+your report. After the initial reply to your report, the owners will
+endeavor to keep you informed of the progress towards a fix and full
+announcement, and may ask for additional information or guidance.
diff --git a/server/node_modules/cookie/index.js b/server/node_modules/cookie/index.js
new file mode 100644
index 0000000..acd5acd
--- /dev/null
+++ b/server/node_modules/cookie/index.js
@@ -0,0 +1,335 @@
+/*!
+ * cookie
+ * Copyright(c) 2012-2014 Roman Shtylman
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module exports.
+ * @public
+ */
+
+exports.parse = parse;
+exports.serialize = serialize;
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var __toString = Object.prototype.toString
+var __hasOwnProperty = Object.prototype.hasOwnProperty
+
+/**
+ * RegExp to match cookie-name in RFC 6265 sec 4.1.1
+ * This refers out to the obsoleted definition of token in RFC 2616 sec 2.2
+ * which has been replaced by the token definition in RFC 7230 appendix B.
+ *
+ * cookie-name       = token
+ * token             = 1*tchar
+ * tchar             = "!" / "#" / "$" / "%" / "&" / "'" /
+ *                     "*" / "+" / "-" / "." / "^" / "_" /
+ *                     "`" / "|" / "~" / DIGIT / ALPHA
+ */
+
+var cookieNameRegExp = /^[!#$%&'*+\-.^_`|~0-9A-Za-z]+$/;
+
+/**
+ * RegExp to match cookie-value in RFC 6265 sec 4.1.1
+ *
+ * cookie-value      = *cookie-octet / ( DQUOTE *cookie-octet DQUOTE )
+ * cookie-octet      = %x21 / %x23-2B / %x2D-3A / %x3C-5B / %x5D-7E
+ *                     ; US-ASCII characters excluding CTLs,
+ *                     ; whitespace DQUOTE, comma, semicolon,
+ *                     ; and backslash
+ */
+
+var cookieValueRegExp = /^("?)[\u0021\u0023-\u002B\u002D-\u003A\u003C-\u005B\u005D-\u007E]*\1$/;
+
+/**
+ * RegExp to match domain-value in RFC 6265 sec 4.1.1
+ *
+ * domain-value      = <subdomain>
+ *                     ; defined in [RFC1034], Section 3.5, as
+ *                     ; enhanced by [RFC1123], Section 2.1
+ * <subdomain>       = <label> | <subdomain> "." <label>
+ * <label>           = <let-dig> [ [ <ldh-str> ] <let-dig> ]
+ *                     Labels must be 63 characters or less.
+ *                     'let-dig' not 'letter' in the first char, per RFC1123
+ * <ldh-str>         = <let-dig-hyp> | <let-dig-hyp> <ldh-str>
+ * <let-dig-hyp>     = <let-dig> | "-"
+ * <let-dig>         = <letter> | <digit>
+ * <letter>          = any one of the 52 alphabetic characters A through Z in
+ *                     upper case and a through z in lower case
+ * <digit>           = any one of the ten digits 0 through 9
+ *
+ * Keep support for leading dot: https://github.com/jshttp/cookie/issues/173
+ *
+ * > (Note that a leading %x2E ("."), if present, is ignored even though that
+ * character is not permitted, but a trailing %x2E ("."), if present, will
+ * cause the user agent to ignore the attribute.)
+ */
+
+var domainValueRegExp = /^([.]?[a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?)([.][a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?)*$/i;
+
+/**
+ * RegExp to match path-value in RFC 6265 sec 4.1.1
+ *
+ * path-value        = <any CHAR except CTLs or ";">
+ * CHAR              = %x01-7F
+ *                     ; defined in RFC 5234 appendix B.1
+ */
+
+var pathValueRegExp = /^[\u0020-\u003A\u003D-\u007E]*$/;
+
+/**
+ * Parse a cookie header.
+ *
+ * Parse the given cookie header string into an object
+ * The object has the various cookies as keys(names) => values
+ *
+ * @param {string} str
+ * @param {object} [opt]
+ * @return {object}
+ * @public
+ */
+
+function parse(str, opt) {
+  if (typeof str !== 'string') {
+    throw new TypeError('argument str must be a string');
+  }
+
+  var obj = {};
+  var len = str.length;
+  // RFC 6265 sec 4.1.1, RFC 2616 2.2 defines a cookie name consists of one char minimum, plus '='.
+  if (len < 2) return obj;
+
+  var dec = (opt && opt.decode) || decode;
+  var index = 0;
+  var eqIdx = 0;
+  var endIdx = 0;
+
+  do {
+    eqIdx = str.indexOf('=', index);
+    if (eqIdx === -1) break; // No more cookie pairs.
+
+    endIdx = str.indexOf(';', index);
+
+    if (endIdx === -1) {
+      endIdx = len;
+    } else if (eqIdx > endIdx) {
+      // backtrack on prior semicolon
+      index = str.lastIndexOf(';', eqIdx - 1) + 1;
+      continue;
+    }
+
+    var keyStartIdx = startIndex(str, index, eqIdx);
+    var keyEndIdx = endIndex(str, eqIdx, keyStartIdx);
+    var key = str.slice(keyStartIdx, keyEndIdx);
+
+    // only assign once
+    if (!__hasOwnProperty.call(obj, key)) {
+      var valStartIdx = startIndex(str, eqIdx + 1, endIdx);
+      var valEndIdx = endIndex(str, endIdx, valStartIdx);
+
+      if (str.charCodeAt(valStartIdx) === 0x22 /* " */ && str.charCodeAt(valEndIdx - 1) === 0x22 /* " */) {
+        valStartIdx++;
+        valEndIdx--;
+      }
+
+      var val = str.slice(valStartIdx, valEndIdx);
+      obj[key] = tryDecode(val, dec);
+    }
+
+    index = endIdx + 1
+  } while (index < len);
+
+  return obj;
+}
+
+function startIndex(str, index, max) {
+  do {
+    var code = str.charCodeAt(index);
+    if (code !== 0x20 /*   */ && code !== 0x09 /* \t */) return index;
+  } while (++index < max);
+  return max;
+}
+
+function endIndex(str, index, min) {
+  while (index > min) {
+    var code = str.charCodeAt(--index);
+    if (code !== 0x20 /*   */ && code !== 0x09 /* \t */) return index + 1;
+  }
+  return min;
+}
+
+/**
+ * Serialize data into a cookie header.
+ *
+ * Serialize a name value pair into a cookie string suitable for
+ * http headers. An optional options object specifies cookie parameters.
+ *
+ * serialize('foo', 'bar', { httpOnly: true })
+ *   => "foo=bar; httpOnly"
+ *
+ * @param {string} name
+ * @param {string} val
+ * @param {object} [opt]
+ * @return {string}
+ * @public
+ */
+
+function serialize(name, val, opt) {
+  var enc = (opt && opt.encode) || encodeURIComponent;
+
+  if (typeof enc !== 'function') {
+    throw new TypeError('option encode is invalid');
+  }
+
+  if (!cookieNameRegExp.test(name)) {
+    throw new TypeError('argument name is invalid');
+  }
+
+  var value = enc(val);
+
+  if (!cookieValueRegExp.test(value)) {
+    throw new TypeError('argument val is invalid');
+  }
+
+  var str = name + '=' + value;
+  if (!opt) return str;
+
+  if (null != opt.maxAge) {
+    var maxAge = Math.floor(opt.maxAge);
+
+    if (!isFinite(maxAge)) {
+      throw new TypeError('option maxAge is invalid')
+    }
+
+    str += '; Max-Age=' + maxAge;
+  }
+
+  if (opt.domain) {
+    if (!domainValueRegExp.test(opt.domain)) {
+      throw new TypeError('option domain is invalid');
+    }
+
+    str += '; Domain=' + opt.domain;
+  }
+
+  if (opt.path) {
+    if (!pathValueRegExp.test(opt.path)) {
+      throw new TypeError('option path is invalid');
+    }
+
+    str += '; Path=' + opt.path;
+  }
+
+  if (opt.expires) {
+    var expires = opt.expires
+
+    if (!isDate(expires) || isNaN(expires.valueOf())) {
+      throw new TypeError('option expires is invalid');
+    }
+
+    str += '; Expires=' + expires.toUTCString()
+  }
+
+  if (opt.httpOnly) {
+    str += '; HttpOnly';
+  }
+
+  if (opt.secure) {
+    str += '; Secure';
+  }
+
+  if (opt.partitioned) {
+    str += '; Partitioned'
+  }
+
+  if (opt.priority) {
+    var priority = typeof opt.priority === 'string'
+      ? opt.priority.toLowerCase() : opt.priority;
+
+    switch (priority) {
+      case 'low':
+        str += '; Priority=Low'
+        break
+      case 'medium':
+        str += '; Priority=Medium'
+        break
+      case 'high':
+        str += '; Priority=High'
+        break
+      default:
+        throw new TypeError('option priority is invalid')
+    }
+  }
+
+  if (opt.sameSite) {
+    var sameSite = typeof opt.sameSite === 'string'
+      ? opt.sameSite.toLowerCase() : opt.sameSite;
+
+    switch (sameSite) {
+      case true:
+        str += '; SameSite=Strict';
+        break;
+      case 'lax':
+        str += '; SameSite=Lax';
+        break;
+      case 'strict':
+        str += '; SameSite=Strict';
+        break;
+      case 'none':
+        str += '; SameSite=None';
+        break;
+      default:
+        throw new TypeError('option sameSite is invalid');
+    }
+  }
+
+  return str;
+}
+
+/**
+ * URL-decode string value. Optimized to skip native call when no %.
+ *
+ * @param {string} str
+ * @returns {string}
+ */
+
+function decode (str) {
+  return str.indexOf('%') !== -1
+    ? decodeURIComponent(str)
+    : str
+}
+
+/**
+ * Determine if value is a Date.
+ *
+ * @param {*} val
+ * @private
+ */
+
+function isDate (val) {
+  return __toString.call(val) === '[object Date]';
+}
+
+/**
+ * Try decoding a string using a decoding function.
+ *
+ * @param {string} str
+ * @param {function} decode
+ * @private
+ */
+
+function tryDecode(str, decode) {
+  try {
+    return decode(str);
+  } catch (e) {
+    return str;
+  }
+}
diff --git a/server/node_modules/cookie/package.json b/server/node_modules/cookie/package.json
new file mode 100644
index 0000000..22e3f92
--- /dev/null
+++ b/server/node_modules/cookie/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "cookie",
+  "description": "HTTP server cookie parsing and serialization",
+  "version": "0.7.2",
+  "author": "Roman Shtylman <shtylman@gmail.com>",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "cookie",
+    "cookies"
+  ],
+  "repository": "jshttp/cookie",
+  "devDependencies": {
+    "beautify-benchmark": "0.2.4",
+    "benchmark": "2.1.4",
+    "eslint": "8.53.0",
+    "eslint-plugin-markdown": "3.0.1",
+    "mocha": "10.2.0",
+    "nyc": "15.1.0",
+    "safe-buffer": "5.2.1",
+    "top-sites": "1.1.194"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "README.md",
+    "SECURITY.md",
+    "index.js"
+  ],
+  "main": "index.js",
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "update-bench": "node scripts/update-benchmark.js"
+  }
+}
diff --git a/server/node_modules/core-util-is/LICENSE b/server/node_modules/core-util-is/LICENSE
new file mode 100644
index 0000000..d8d7f94
--- /dev/null
+++ b/server/node_modules/core-util-is/LICENSE
@@ -0,0 +1,19 @@
+Copyright Node.js contributors. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
diff --git a/server/node_modules/core-util-is/README.md b/server/node_modules/core-util-is/README.md
new file mode 100644
index 0000000..5a76b41
--- /dev/null
+++ b/server/node_modules/core-util-is/README.md
@@ -0,0 +1,3 @@
+# core-util-is
+
+The `util.is*` functions introduced in Node v0.12.
diff --git a/server/node_modules/core-util-is/lib/util.js b/server/node_modules/core-util-is/lib/util.js
new file mode 100644
index 0000000..6e5a20d
--- /dev/null
+++ b/server/node_modules/core-util-is/lib/util.js
@@ -0,0 +1,107 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// NOTE: These type checking functions intentionally don't use `instanceof`
+// because it is fragile and can be easily faked with `Object.create()`.
+
+function isArray(arg) {
+  if (Array.isArray) {
+    return Array.isArray(arg);
+  }
+  return objectToString(arg) === '[object Array]';
+}
+exports.isArray = isArray;
+
+function isBoolean(arg) {
+  return typeof arg === 'boolean';
+}
+exports.isBoolean = isBoolean;
+
+function isNull(arg) {
+  return arg === null;
+}
+exports.isNull = isNull;
+
+function isNullOrUndefined(arg) {
+  return arg == null;
+}
+exports.isNullOrUndefined = isNullOrUndefined;
+
+function isNumber(arg) {
+  return typeof arg === 'number';
+}
+exports.isNumber = isNumber;
+
+function isString(arg) {
+  return typeof arg === 'string';
+}
+exports.isString = isString;
+
+function isSymbol(arg) {
+  return typeof arg === 'symbol';
+}
+exports.isSymbol = isSymbol;
+
+function isUndefined(arg) {
+  return arg === void 0;
+}
+exports.isUndefined = isUndefined;
+
+function isRegExp(re) {
+  return objectToString(re) === '[object RegExp]';
+}
+exports.isRegExp = isRegExp;
+
+function isObject(arg) {
+  return typeof arg === 'object' && arg !== null;
+}
+exports.isObject = isObject;
+
+function isDate(d) {
+  return objectToString(d) === '[object Date]';
+}
+exports.isDate = isDate;
+
+function isError(e) {
+  return (objectToString(e) === '[object Error]' || e instanceof Error);
+}
+exports.isError = isError;
+
+function isFunction(arg) {
+  return typeof arg === 'function';
+}
+exports.isFunction = isFunction;
+
+function isPrimitive(arg) {
+  return arg === null ||
+         typeof arg === 'boolean' ||
+         typeof arg === 'number' ||
+         typeof arg === 'string' ||
+         typeof arg === 'symbol' ||  // ES6 symbol
+         typeof arg === 'undefined';
+}
+exports.isPrimitive = isPrimitive;
+
+exports.isBuffer = require('buffer').Buffer.isBuffer;
+
+function objectToString(o) {
+  return Object.prototype.toString.call(o);
+}
diff --git a/server/node_modules/core-util-is/package.json b/server/node_modules/core-util-is/package.json
new file mode 100644
index 0000000..b0c51f5
--- /dev/null
+++ b/server/node_modules/core-util-is/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "core-util-is",
+  "version": "1.0.3",
+  "description": "The `util.is*` functions introduced in Node v0.12.",
+  "main": "lib/util.js",
+  "files": [
+    "lib"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/isaacs/core-util-is"
+  },
+  "keywords": [
+    "util",
+    "isBuffer",
+    "isArray",
+    "isNumber",
+    "isString",
+    "isRegExp",
+    "isThis",
+    "isThat",
+    "polyfill"
+  ],
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/isaacs/core-util-is/issues"
+  },
+  "scripts": {
+    "test": "tap test.js",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags"
+  },
+  "devDependencies": {
+    "tap": "^15.0.9"
+  }
+}
diff --git a/server/node_modules/cors/LICENSE b/server/node_modules/cors/LICENSE
new file mode 100644
index 0000000..fd10c84
--- /dev/null
+++ b/server/node_modules/cors/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2013 Troy Goode <troygoode@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/cors/README.md b/server/node_modules/cors/README.md
new file mode 100644
index 0000000..3d206e5
--- /dev/null
+++ b/server/node_modules/cors/README.md
@@ -0,0 +1,277 @@
+# cors
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Build Status][github-actions-ci-image]][github-actions-ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+CORS is a [Node.js](https://nodejs.org/en/) middleware for [Express](https://expressjs.com/)/[Connect](https://github.com/senchalabs/connect) that sets [CORS](https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/CORS) response headers. These headers tell browsers which origins can read responses from your server.
+
+> [!IMPORTANT]
+> **How CORS Works:** This package sets response headers—it doesn't block requests. CORS is enforced by browsers: they check the headers and decide if JavaScript can read the response. Non-browser clients (curl, Postman, other servers) ignore CORS entirely. See the [MDN CORS guide](https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/CORS) for details.
+
+* [Installation](#installation)
+* [Usage](#usage)
+  * [Simple Usage](#simple-usage-enable-all-cors-requests)
+  * [Enable CORS for a Single Route](#enable-cors-for-a-single-route)
+  * [Configuring CORS](#configuring-cors)
+  * [Configuring CORS w/ Dynamic Origin](#configuring-cors-w-dynamic-origin)
+  * [Enabling CORS Pre-Flight](#enabling-cors-pre-flight)
+  * [Customizing CORS Settings Dynamically per Request](#customizing-cors-settings-dynamically-per-request)
+* [Configuration Options](#configuration-options)
+* [Common Misconceptions](#common-misconceptions)
+* [License](#license)
+* [Original Author](#original-author)
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/downloading-and-installing-packages-locally):
+
+```sh
+$ npm install cors
+```
+
+## Usage
+
+### Simple Usage (Enable *All* CORS Requests)
+
+```javascript
+var express = require('express')
+var cors = require('cors')
+var app = express()
+
+// Adds headers: Access-Control-Allow-Origin: *
+app.use(cors())
+
+app.get('/products/:id', function (req, res, next) {
+  res.json({msg: 'Hello'})
+})
+
+app.listen(80, function () {
+  console.log('web server listening on port 80')
+})
+```
+
+### Enable CORS for a Single Route
+
+```javascript
+var express = require('express')
+var cors = require('cors')
+var app = express()
+
+// Adds headers: Access-Control-Allow-Origin: *
+app.get('/products/:id', cors(), function (req, res, next) {
+  res.json({msg: 'Hello'})
+})
+
+app.listen(80, function () {
+  console.log('web server listening on port 80')
+})
+```
+
+### Configuring CORS
+
+See the [configuration options](#configuration-options) for details.
+
+```javascript
+var express = require('express')
+var cors = require('cors')
+var app = express()
+
+var corsOptions = {
+  origin: 'http://example.com',
+  optionsSuccessStatus: 200 // some legacy browsers (IE11, various SmartTVs) choke on 204
+}
+
+// Adds headers: Access-Control-Allow-Origin: http://example.com, Vary: Origin
+app.get('/products/:id', cors(corsOptions), function (req, res, next) {
+  res.json({msg: 'Hello'})
+})
+
+app.listen(80, function () {
+  console.log('web server listening on port 80')
+})
+```
+
+### Configuring CORS w/ Dynamic Origin
+
+This module supports validating the origin dynamically using a function provided
+to the `origin` option. This function will be passed a string that is the origin
+(or `undefined` if the request has no origin), and a `callback` with the signature
+`callback(error, origin)`.
+
+The `origin` argument to the callback can be any value allowed for the `origin`
+option of the middleware, except a function. See the
+[configuration options](#configuration-options) section for more information on all
+the possible value types.
+
+This function is designed to allow the dynamic loading of allowed origin(s) from
+a backing datasource, like a database.
+
+```javascript
+var express = require('express')
+var cors = require('cors')
+var app = express()
+
+var corsOptions = {
+  origin: function (origin, callback) {
+    // db.loadOrigins is an example call to load
+    // a list of origins from a backing database
+    db.loadOrigins(function (error, origins) {
+      callback(error, origins)
+    })
+  }
+}
+
+// Adds headers: Access-Control-Allow-Origin: <matched origin>, Vary: Origin
+app.get('/products/:id', cors(corsOptions), function (req, res, next) {
+  res.json({msg: 'Hello'})
+})
+
+app.listen(80, function () {
+  console.log('web server listening on port 80')
+})
+```
+
+### Enabling CORS Pre-Flight
+
+Certain CORS requests are considered 'complex' and require an initial
+`OPTIONS` request (called the "pre-flight request"). An example of a
+'complex' CORS request is one that uses an HTTP verb other than
+GET/HEAD/POST (such as DELETE) or that uses custom headers. To enable
+pre-flighting, you must add a new OPTIONS handler for the route you want
+to support:
+
+```javascript
+var express = require('express')
+var cors = require('cors')
+var app = express()
+
+app.options('/products/:id', cors()) // preflight for DELETE
+app.del('/products/:id', cors(), function (req, res, next) {
+  res.json({msg: 'Hello'})
+})
+
+app.listen(80, function () {
+  console.log('web server listening on port 80')
+})
+```
+
+You can also enable pre-flight across-the-board like so:
+
+```javascript
+app.options('*', cors()) // include before other routes
+```
+
+NOTE: When using this middleware as an application level middleware (for
+example, `app.use(cors())`), pre-flight requests are already handled for all
+routes.
+
+### Customizing CORS Settings Dynamically per Request
+
+For APIs that require different CORS configurations for specific routes or requests, you can dynamically generate CORS options based on the incoming request. The `cors` middleware allows you to achieve this by passing a function instead of static options. This function is called for each incoming request and must use the callback pattern to return the appropriate CORS options.
+
+The function accepts:
+1. **`req`**: 
+   - The incoming request object.
+
+2. **`callback(error, corsOptions)`**: 
+   - A function used to return the computed CORS options.
+   - **Arguments**:
+     - **`error`**: Pass `null` if there’s no error, or an error object to indicate a failure.
+     - **`corsOptions`**: An object specifying the CORS policy for the current request.
+
+Here’s an example that handles both public routes and restricted, credential-sensitive routes:
+
+```javascript
+var dynamicCorsOptions = function(req, callback) {
+  var corsOptions;
+  if (req.path.startsWith('/auth/connect/')) {
+    // Access-Control-Allow-Origin: http://mydomain.com, Access-Control-Allow-Credentials: true, Vary: Origin
+    corsOptions = {
+      origin: 'http://mydomain.com',
+      credentials: true
+    };
+  } else {
+    // Access-Control-Allow-Origin: *
+    corsOptions = { origin: '*' };
+  }
+  callback(null, corsOptions);
+};
+
+app.use(cors(dynamicCorsOptions));
+
+app.get('/auth/connect/twitter', function (req, res) {
+  res.send('Hello');
+});
+
+app.get('/public', function (req, res) {
+  res.send('Hello');
+});
+
+app.listen(80, function () {
+  console.log('web server listening on port 80')
+})
+```
+
+## Configuration Options
+
+* `origin`: Configures the **Access-Control-Allow-Origin** CORS header. Possible values:
+  - `Boolean` - set `origin` to `true` to reflect the [request origin](https://datatracker.ietf.org/doc/html/draft-abarth-origin-09), as defined by `req.header('Origin')`, or set it to `false` to disable CORS.
+  - `String` - set `origin` to a specific origin. For example, if you set it to
+    - `"http://example.com"` only requests from "http://example.com" will be allowed.
+    - `"*"` for all domains to be allowed. 
+  - `RegExp` - set `origin` to a regular expression pattern which will be used to test the request origin. If it's a match, the request origin will be reflected. For example the pattern `/example\.com$/` will reflect any request that is coming from an origin ending with "example.com".
+  - `Array` - set `origin` to an array of valid origins. Each origin can be a `String` or a `RegExp`. For example `["http://example1.com", /\.example2\.com$/]` will accept any request from "http://example1.com" or from a subdomain of "example2.com".
+  - `Function` - set `origin` to a function implementing some custom logic. The function takes the request origin as the first parameter and a callback (called as `callback(err, origin)`, where `origin` is a non-function value of the `origin` option) as the second.
+* `methods`: Configures the **Access-Control-Allow-Methods** CORS header. Expects a comma-delimited string (ex: 'GET,PUT,POST') or an array (ex: `['GET', 'PUT', 'POST']`).
+* `allowedHeaders`: Configures the **Access-Control-Allow-Headers** CORS header. Expects a comma-delimited string (ex: 'Content-Type,Authorization') or an array (ex: `['Content-Type', 'Authorization']`). If not specified, defaults to reflecting the headers specified in the request's **Access-Control-Request-Headers** header.
+* `exposedHeaders`: Configures the **Access-Control-Expose-Headers** CORS header. Expects a comma-delimited string (ex: 'Content-Range,X-Content-Range') or an array (ex: `['Content-Range', 'X-Content-Range']`). If not specified, no custom headers are exposed.
+* `credentials`: Configures the **Access-Control-Allow-Credentials** CORS header. Set to `true` to pass the header, otherwise it is omitted.
+* `maxAge`: Configures the **Access-Control-Max-Age** CORS header. Set to an integer to pass the header, otherwise it is omitted.
+* `preflightContinue`: Pass the CORS preflight response to the next handler.
+* `optionsSuccessStatus`: Provides a status code to use for successful `OPTIONS` requests, since some legacy browsers (IE11, various SmartTVs) choke on `204`.
+
+The default configuration is the equivalent of:
+
+```json
+{
+  "origin": "*",
+  "methods": "GET,HEAD,PUT,PATCH,POST,DELETE",
+  "preflightContinue": false,
+  "optionsSuccessStatus": 204
+}
+```
+
+## Common Misconceptions
+
+### "CORS blocks requests from disallowed origins"
+
+**No.** Your server receives and processes every request. CORS headers tell the browser whether JavaScript can read the response—not whether the request is allowed.
+
+### "CORS protects my API from unauthorized access"
+
+**No.** CORS is not access control. Any HTTP client (curl, Postman, another server) can call your API regardless of CORS settings. Use authentication and authorization to protect your API.
+
+### "Setting `origin: 'http://example.com'` means only that domain can access my server"
+
+**No.** It means browsers will only let JavaScript from that origin read responses. The server still responds to all requests.
+
+## License
+
+[MIT License](http://www.opensource.org/licenses/mit-license.php)
+
+## Original Author
+
+[Troy Goode](https://github.com/TroyGoode) ([troygoode@gmail.com](mailto:troygoode@gmail.com))
+
+[coveralls-image]: https://img.shields.io/coveralls/expressjs/cors/master.svg
+[coveralls-url]: https://coveralls.io/r/expressjs/cors?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/cors.svg
+[downloads-url]: https://npmjs.com/package/cors
+[github-actions-ci-image]: https://img.shields.io/github/actions/workflow/status/expressjs/cors/ci.yml?branch=master&label=ci
+[github-actions-ci-url]: https://github.com/expressjs/cors?query=workflow%3Aci
+[npm-image]: https://img.shields.io/npm/v/cors.svg
+[npm-url]: https://npmjs.com/package/cors
diff --git a/server/node_modules/cors/lib/index.js b/server/node_modules/cors/lib/index.js
new file mode 100644
index 0000000..ad899ca
--- /dev/null
+++ b/server/node_modules/cors/lib/index.js
@@ -0,0 +1,238 @@
+(function () {
+
+  'use strict';
+
+  var assign = require('object-assign');
+  var vary = require('vary');
+
+  var defaults = {
+    origin: '*',
+    methods: 'GET,HEAD,PUT,PATCH,POST,DELETE',
+    preflightContinue: false,
+    optionsSuccessStatus: 204
+  };
+
+  function isString(s) {
+    return typeof s === 'string' || s instanceof String;
+  }
+
+  function isOriginAllowed(origin, allowedOrigin) {
+    if (Array.isArray(allowedOrigin)) {
+      for (var i = 0; i < allowedOrigin.length; ++i) {
+        if (isOriginAllowed(origin, allowedOrigin[i])) {
+          return true;
+        }
+      }
+      return false;
+    } else if (isString(allowedOrigin)) {
+      return origin === allowedOrigin;
+    } else if (allowedOrigin instanceof RegExp) {
+      return allowedOrigin.test(origin);
+    } else {
+      return !!allowedOrigin;
+    }
+  }
+
+  function configureOrigin(options, req) {
+    var requestOrigin = req.headers.origin,
+      headers = [],
+      isAllowed;
+
+    if (!options.origin || options.origin === '*') {
+      // allow any origin
+      headers.push([{
+        key: 'Access-Control-Allow-Origin',
+        value: '*'
+      }]);
+    } else if (isString(options.origin)) {
+      // fixed origin
+      headers.push([{
+        key: 'Access-Control-Allow-Origin',
+        value: options.origin
+      }]);
+      headers.push([{
+        key: 'Vary',
+        value: 'Origin'
+      }]);
+    } else {
+      isAllowed = isOriginAllowed(requestOrigin, options.origin);
+      // reflect origin
+      headers.push([{
+        key: 'Access-Control-Allow-Origin',
+        value: isAllowed ? requestOrigin : false
+      }]);
+      headers.push([{
+        key: 'Vary',
+        value: 'Origin'
+      }]);
+    }
+
+    return headers;
+  }
+
+  function configureMethods(options) {
+    var methods = options.methods;
+    if (methods.join) {
+      methods = options.methods.join(','); // .methods is an array, so turn it into a string
+    }
+    return {
+      key: 'Access-Control-Allow-Methods',
+      value: methods
+    };
+  }
+
+  function configureCredentials(options) {
+    if (options.credentials === true) {
+      return {
+        key: 'Access-Control-Allow-Credentials',
+        value: 'true'
+      };
+    }
+    return null;
+  }
+
+  function configureAllowedHeaders(options, req) {
+    var allowedHeaders = options.allowedHeaders || options.headers;
+    var headers = [];
+
+    if (!allowedHeaders) {
+      allowedHeaders = req.headers['access-control-request-headers']; // .headers wasn't specified, so reflect the request headers
+      headers.push([{
+        key: 'Vary',
+        value: 'Access-Control-Request-Headers'
+      }]);
+    } else if (allowedHeaders.join) {
+      allowedHeaders = allowedHeaders.join(','); // .headers is an array, so turn it into a string
+    }
+    if (allowedHeaders && allowedHeaders.length) {
+      headers.push([{
+        key: 'Access-Control-Allow-Headers',
+        value: allowedHeaders
+      }]);
+    }
+
+    return headers;
+  }
+
+  function configureExposedHeaders(options) {
+    var headers = options.exposedHeaders;
+    if (!headers) {
+      return null;
+    } else if (headers.join) {
+      headers = headers.join(','); // .headers is an array, so turn it into a string
+    }
+    if (headers && headers.length) {
+      return {
+        key: 'Access-Control-Expose-Headers',
+        value: headers
+      };
+    }
+    return null;
+  }
+
+  function configureMaxAge(options) {
+    var maxAge = (typeof options.maxAge === 'number' || options.maxAge) && options.maxAge.toString()
+    if (maxAge && maxAge.length) {
+      return {
+        key: 'Access-Control-Max-Age',
+        value: maxAge
+      };
+    }
+    return null;
+  }
+
+  function applyHeaders(headers, res) {
+    for (var i = 0, n = headers.length; i < n; i++) {
+      var header = headers[i];
+      if (header) {
+        if (Array.isArray(header)) {
+          applyHeaders(header, res);
+        } else if (header.key === 'Vary' && header.value) {
+          vary(res, header.value);
+        } else if (header.value) {
+          res.setHeader(header.key, header.value);
+        }
+      }
+    }
+  }
+
+  function cors(options, req, res, next) {
+    var headers = [],
+      method = req.method && req.method.toUpperCase && req.method.toUpperCase();
+
+    if (method === 'OPTIONS') {
+      // preflight
+      headers.push(configureOrigin(options, req));
+      headers.push(configureCredentials(options))
+      headers.push(configureMethods(options))
+      headers.push(configureAllowedHeaders(options, req));
+      headers.push(configureMaxAge(options))
+      headers.push(configureExposedHeaders(options))
+      applyHeaders(headers, res);
+
+      if (options.preflightContinue) {
+        next();
+      } else {
+        // Safari (and potentially other browsers) need content-length 0,
+        //   for 204 or they just hang waiting for a body
+        res.statusCode = options.optionsSuccessStatus;
+        res.setHeader('Content-Length', '0');
+        res.end();
+      }
+    } else {
+      // actual response
+      headers.push(configureOrigin(options, req));
+      headers.push(configureCredentials(options))
+      headers.push(configureExposedHeaders(options))
+      applyHeaders(headers, res);
+      next();
+    }
+  }
+
+  function middlewareWrapper(o) {
+    // if options are static (either via defaults or custom options passed in), wrap in a function
+    var optionsCallback = null;
+    if (typeof o === 'function') {
+      optionsCallback = o;
+    } else {
+      optionsCallback = function (req, cb) {
+        cb(null, o);
+      };
+    }
+
+    return function corsMiddleware(req, res, next) {
+      optionsCallback(req, function (err, options) {
+        if (err) {
+          next(err);
+        } else {
+          var corsOptions = assign({}, defaults, options);
+          var originCallback = null;
+          if (corsOptions.origin && typeof corsOptions.origin === 'function') {
+            originCallback = corsOptions.origin;
+          } else if (corsOptions.origin) {
+            originCallback = function (origin, cb) {
+              cb(null, corsOptions.origin);
+            };
+          }
+
+          if (originCallback) {
+            originCallback(req.headers.origin, function (err2, origin) {
+              if (err2 || !origin) {
+                next(err2);
+              } else {
+                corsOptions.origin = origin;
+                cors(corsOptions, req, res, next);
+              }
+            });
+          } else {
+            next();
+          }
+        }
+      });
+    };
+  }
+
+  // can pass either an options hash, an options delegate, or nothing
+  module.exports = middlewareWrapper;
+
+}());
diff --git a/server/node_modules/cors/package.json b/server/node_modules/cors/package.json
new file mode 100644
index 0000000..e90bac8
--- /dev/null
+++ b/server/node_modules/cors/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "cors",
+  "description": "Node.js CORS middleware",
+  "version": "2.8.6",
+  "author": "Troy Goode <troygoode@gmail.com> (https://github.com/troygoode/)",
+  "license": "MIT",
+  "keywords": [
+    "cors",
+    "express",
+    "connect",
+    "middleware"
+  ],
+  "repository": "expressjs/cors",
+  "funding": {
+    "type": "opencollective",
+    "url": "https://opencollective.com/express"
+  },
+  "main": "./lib/index.js",
+  "dependencies": {
+    "object-assign": "^4",
+    "vary": "^1"
+  },
+  "devDependencies": {
+    "after": "0.8.2",
+    "eslint": "7.30.0",
+    "express": "4.21.2",
+    "mocha": "9.2.2",
+    "nyc": "15.1.0",
+    "supertest": "6.1.3"
+  },
+  "files": [
+    "lib/index.js"
+  ],
+  "engines": {
+    "node": ">= 0.10"
+  },
+  "scripts": {
+    "test": "npm run lint && npm run test-ci",
+    "test-ci": "nyc --reporter=lcov --reporter=text mocha --require test/support/env",
+    "lint": "eslint lib test"
+  }
+}
diff --git a/server/node_modules/debug/.coveralls.yml b/server/node_modules/debug/.coveralls.yml
new file mode 100644
index 0000000..20a7068
--- /dev/null
+++ b/server/node_modules/debug/.coveralls.yml
@@ -0,0 +1 @@
+repo_token: SIAeZjKYlHK74rbcFvNHMUzjRiMpflxve
diff --git a/server/node_modules/debug/.eslintrc b/server/node_modules/debug/.eslintrc
new file mode 100644
index 0000000..8a37ae2
--- /dev/null
+++ b/server/node_modules/debug/.eslintrc
@@ -0,0 +1,11 @@
+{
+  "env": {
+    "browser": true,
+    "node": true
+  },
+  "rules": {
+    "no-console": 0,
+    "no-empty": [1, { "allowEmptyCatch": true }]
+  },
+  "extends": "eslint:recommended"
+}
diff --git a/server/node_modules/debug/.npmignore b/server/node_modules/debug/.npmignore
new file mode 100644
index 0000000..5f60eec
--- /dev/null
+++ b/server/node_modules/debug/.npmignore
@@ -0,0 +1,9 @@
+support
+test
+examples
+example
+*.sock
+dist
+yarn.lock
+coverage
+bower.json
diff --git a/server/node_modules/debug/.travis.yml b/server/node_modules/debug/.travis.yml
new file mode 100644
index 0000000..6c6090c
--- /dev/null
+++ b/server/node_modules/debug/.travis.yml
@@ -0,0 +1,14 @@
+
+language: node_js
+node_js:
+  - "6"
+  - "5"
+  - "4"
+
+install:
+  - make node_modules
+
+script:
+  - make lint
+  - make test
+  - make coveralls
diff --git a/server/node_modules/debug/CHANGELOG.md b/server/node_modules/debug/CHANGELOG.md
new file mode 100644
index 0000000..eadaa18
--- /dev/null
+++ b/server/node_modules/debug/CHANGELOG.md
@@ -0,0 +1,362 @@
+
+2.6.9 / 2017-09-22
+==================
+
+  * remove ReDoS regexp in %o formatter (#504)
+
+2.6.8 / 2017-05-18
+==================
+
+  * Fix: Check for undefined on browser globals (#462, @marbemac)
+
+2.6.7 / 2017-05-16
+==================
+
+  * Fix: Update ms to 2.0.0 to fix regular expression denial of service vulnerability (#458, @hubdotcom)
+  * Fix: Inline extend function in node implementation (#452, @dougwilson)
+  * Docs: Fix typo (#455, @msasad)
+
+2.6.5 / 2017-04-27
+==================
+  
+  * Fix: null reference check on window.documentElement.style.WebkitAppearance (#447, @thebigredgeek)
+  * Misc: clean up browser reference checks (#447, @thebigredgeek)
+  * Misc: add npm-debug.log to .gitignore (@thebigredgeek)
+
+
+2.6.4 / 2017-04-20
+==================
+
+  * Fix: bug that would occure if process.env.DEBUG is a non-string value. (#444, @LucianBuzzo)
+  * Chore: ignore bower.json in npm installations. (#437, @joaovieira)
+  * Misc: update "ms" to v0.7.3 (@tootallnate)
+
+2.6.3 / 2017-03-13
+==================
+
+  * Fix: Electron reference to `process.env.DEBUG` (#431, @paulcbetts)
+  * Docs: Changelog fix (@thebigredgeek)
+
+2.6.2 / 2017-03-10
+==================
+
+  * Fix: DEBUG_MAX_ARRAY_LENGTH (#420, @slavaGanzin)
+  * Docs: Add backers and sponsors from Open Collective (#422, @piamancini)
+  * Docs: Add Slackin invite badge (@tootallnate)
+
+2.6.1 / 2017-02-10
+==================
+
+  * Fix: Module's `export default` syntax fix for IE8 `Expected identifier` error
+  * Fix: Whitelist DEBUG_FD for values 1 and 2 only (#415, @pi0)
+  * Fix: IE8 "Expected identifier" error (#414, @vgoma)
+  * Fix: Namespaces would not disable once enabled (#409, @musikov)
+
+2.6.0 / 2016-12-28
+==================
+
+  * Fix: added better null pointer checks for browser useColors (@thebigredgeek)
+  * Improvement: removed explicit `window.debug` export (#404, @tootallnate)
+  * Improvement: deprecated `DEBUG_FD` environment variable (#405, @tootallnate)
+
+2.5.2 / 2016-12-25
+==================
+
+  * Fix: reference error on window within webworkers (#393, @KlausTrainer)
+  * Docs: fixed README typo (#391, @lurch)
+  * Docs: added notice about v3 api discussion (@thebigredgeek)
+
+2.5.1 / 2016-12-20
+==================
+
+  * Fix: babel-core compatibility
+
+2.5.0 / 2016-12-20
+==================
+
+  * Fix: wrong reference in bower file (@thebigredgeek)
+  * Fix: webworker compatibility (@thebigredgeek)
+  * Fix: output formatting issue (#388, @kribblo)
+  * Fix: babel-loader compatibility (#383, @escwald)
+  * Misc: removed built asset from repo and publications (@thebigredgeek)
+  * Misc: moved source files to /src (#378, @yamikuronue)
+  * Test: added karma integration and replaced babel with browserify for browser tests (#378, @yamikuronue)
+  * Test: coveralls integration (#378, @yamikuronue)
+  * Docs: simplified language in the opening paragraph (#373, @yamikuronue)
+
+2.4.5 / 2016-12-17
+==================
+
+  * Fix: `navigator` undefined in Rhino (#376, @jochenberger)
+  * Fix: custom log function (#379, @hsiliev)
+  * Improvement: bit of cleanup + linting fixes (@thebigredgeek)
+  * Improvement: rm non-maintainted `dist/` dir (#375, @freewil)
+  * Docs: simplified language in the opening paragraph. (#373, @yamikuronue)
+
+2.4.4 / 2016-12-14
+==================
+
+  * Fix: work around debug being loaded in preload scripts for electron (#368, @paulcbetts)
+
+2.4.3 / 2016-12-14
+==================
+
+  * Fix: navigation.userAgent error for react native (#364, @escwald)
+
+2.4.2 / 2016-12-14
+==================
+
+  * Fix: browser colors (#367, @tootallnate)
+  * Misc: travis ci integration (@thebigredgeek)
+  * Misc: added linting and testing boilerplate with sanity check (@thebigredgeek)
+
+2.4.1 / 2016-12-13
+==================
+
+  * Fix: typo that broke the package (#356)
+
+2.4.0 / 2016-12-13
+==================
+
+  * Fix: bower.json references unbuilt src entry point (#342, @justmatt)
+  * Fix: revert "handle regex special characters" (@tootallnate)
+  * Feature: configurable util.inspect()`options for NodeJS (#327, @tootallnate)
+  * Feature: %O`(big O) pretty-prints objects (#322, @tootallnate)
+  * Improvement: allow colors in workers (#335, @botverse)
+  * Improvement: use same color for same namespace. (#338, @lchenay)
+
+2.3.3 / 2016-11-09
+==================
+
+  * Fix: Catch `JSON.stringify()` errors (#195, Jovan Alleyne)
+  * Fix: Returning `localStorage` saved values (#331, Levi Thomason)
+  * Improvement: Don't create an empty object when no `process` (Nathan Rajlich)
+
+2.3.2 / 2016-11-09
+==================
+
+  * Fix: be super-safe in index.js as well (@TooTallNate)
+  * Fix: should check whether process exists (Tom Newby)
+
+2.3.1 / 2016-11-09
+==================
+
+  * Fix: Added electron compatibility (#324, @paulcbetts)
+  * Improvement: Added performance optimizations (@tootallnate)
+  * Readme: Corrected PowerShell environment variable example (#252, @gimre)
+  * Misc: Removed yarn lock file from source control (#321, @fengmk2)
+
+2.3.0 / 2016-11-07
+==================
+
+  * Fix: Consistent placement of ms diff at end of output (#215, @gorangajic)
+  * Fix: Escaping of regex special characters in namespace strings (#250, @zacronos)
+  * Fix: Fixed bug causing crash on react-native (#282, @vkarpov15)
+  * Feature: Enabled ES6+ compatible import via default export (#212 @bucaran)
+  * Feature: Added %O formatter to reflect Chrome's console.log capability (#279, @oncletom)
+  * Package: Update "ms" to 0.7.2 (#315, @DevSide)
+  * Package: removed superfluous version property from bower.json (#207 @kkirsche)
+  * Readme: fix USE_COLORS to DEBUG_COLORS
+  * Readme: Doc fixes for format string sugar (#269, @mlucool)
+  * Readme: Updated docs for DEBUG_FD and DEBUG_COLORS environment variables (#232, @mattlyons0)
+  * Readme: doc fixes for PowerShell (#271 #243, @exoticknight @unreadable)
+  * Readme: better docs for browser support (#224, @matthewmueller)
+  * Tooling: Added yarn integration for development (#317, @thebigredgeek)
+  * Misc: Renamed History.md to CHANGELOG.md (@thebigredgeek)
+  * Misc: Added license file (#226 #274, @CantemoInternal @sdaitzman)
+  * Misc: Updated contributors (@thebigredgeek)
+
+2.2.0 / 2015-05-09
+==================
+
+  * package: update "ms" to v0.7.1 (#202, @dougwilson)
+  * README: add logging to file example (#193, @DanielOchoa)
+  * README: fixed a typo (#191, @amir-s)
+  * browser: expose `storage` (#190, @stephenmathieson)
+  * Makefile: add a `distclean` target (#189, @stephenmathieson)
+
+2.1.3 / 2015-03-13
+==================
+
+  * Updated stdout/stderr example (#186)
+  * Updated example/stdout.js to match debug current behaviour
+  * Renamed example/stderr.js to stdout.js
+  * Update Readme.md (#184)
+  * replace high intensity foreground color for bold (#182, #183)
+
+2.1.2 / 2015-03-01
+==================
+
+  * dist: recompile
+  * update "ms" to v0.7.0
+  * package: update "browserify" to v9.0.3
+  * component: fix "ms.js" repo location
+  * changed bower package name
+  * updated documentation about using debug in a browser
+  * fix: security error on safari (#167, #168, @yields)
+
+2.1.1 / 2014-12-29
+==================
+
+  * browser: use `typeof` to check for `console` existence
+  * browser: check for `console.log` truthiness (fix IE 8/9)
+  * browser: add support for Chrome apps
+  * Readme: added Windows usage remarks
+  * Add `bower.json` to properly support bower install
+
+2.1.0 / 2014-10-15
+==================
+
+  * node: implement `DEBUG_FD` env variable support
+  * package: update "browserify" to v6.1.0
+  * package: add "license" field to package.json (#135, @panuhorsmalahti)
+
+2.0.0 / 2014-09-01
+==================
+
+  * package: update "browserify" to v5.11.0
+  * node: use stderr rather than stdout for logging (#29, @stephenmathieson)
+
+1.0.4 / 2014-07-15
+==================
+
+  * dist: recompile
+  * example: remove `console.info()` log usage
+  * example: add "Content-Type" UTF-8 header to browser example
+  * browser: place %c marker after the space character
+  * browser: reset the "content" color via `color: inherit`
+  * browser: add colors support for Firefox >= v31
+  * debug: prefer an instance `log()` function over the global one (#119)
+  * Readme: update documentation about styled console logs for FF v31 (#116, @wryk)
+
+1.0.3 / 2014-07-09
+==================
+
+  * Add support for multiple wildcards in namespaces (#122, @seegno)
+  * browser: fix lint
+
+1.0.2 / 2014-06-10
+==================
+
+  * browser: update color palette (#113, @gscottolson)
+  * common: make console logging function configurable (#108, @timoxley)
+  * node: fix %o colors on old node <= 0.8.x
+  * Makefile: find node path using shell/which (#109, @timoxley)
+
+1.0.1 / 2014-06-06
+==================
+
+  * browser: use `removeItem()` to clear localStorage
+  * browser, node: don't set DEBUG if namespaces is undefined (#107, @leedm777)
+  * package: add "contributors" section
+  * node: fix comment typo
+  * README: list authors
+
+1.0.0 / 2014-06-04
+==================
+
+  * make ms diff be global, not be scope
+  * debug: ignore empty strings in enable()
+  * node: make DEBUG_COLORS able to disable coloring
+  * *: export the `colors` array
+  * npmignore: don't publish the `dist` dir
+  * Makefile: refactor to use browserify
+  * package: add "browserify" as a dev dependency
+  * Readme: add Web Inspector Colors section
+  * node: reset terminal color for the debug content
+  * node: map "%o" to `util.inspect()`
+  * browser: map "%j" to `JSON.stringify()`
+  * debug: add custom "formatters"
+  * debug: use "ms" module for humanizing the diff
+  * Readme: add "bash" syntax highlighting
+  * browser: add Firebug color support
+  * browser: add colors for WebKit browsers
+  * node: apply log to `console`
+  * rewrite: abstract common logic for Node & browsers
+  * add .jshintrc file
+
+0.8.1 / 2014-04-14
+==================
+
+  * package: re-add the "component" section
+
+0.8.0 / 2014-03-30
+==================
+
+  * add `enable()` method for nodejs. Closes #27
+  * change from stderr to stdout
+  * remove unnecessary index.js file
+
+0.7.4 / 2013-11-13
+==================
+
+  * remove "browserify" key from package.json (fixes something in browserify)
+
+0.7.3 / 2013-10-30
+==================
+
+  * fix: catch localStorage security error when cookies are blocked (Chrome)
+  * add debug(err) support. Closes #46
+  * add .browser prop to package.json. Closes #42
+
+0.7.2 / 2013-02-06
+==================
+
+  * fix package.json
+  * fix: Mobile Safari (private mode) is broken with debug
+  * fix: Use unicode to send escape character to shell instead of octal to work with strict mode javascript
+
+0.7.1 / 2013-02-05
+==================
+
+  * add repository URL to package.json
+  * add DEBUG_COLORED to force colored output
+  * add browserify support
+  * fix component. Closes #24
+
+0.7.0 / 2012-05-04
+==================
+
+  * Added .component to package.json
+  * Added debug.component.js build
+
+0.6.0 / 2012-03-16
+==================
+
+  * Added support for "-" prefix in DEBUG [Vinay Pulim]
+  * Added `.enabled` flag to the node version [TooTallNate]
+
+0.5.0 / 2012-02-02
+==================
+
+  * Added: humanize diffs. Closes #8
+  * Added `debug.disable()` to the CS variant
+  * Removed padding. Closes #10
+  * Fixed: persist client-side variant again. Closes #9
+
+0.4.0 / 2012-02-01
+==================
+
+  * Added browser variant support for older browsers [TooTallNate]
+  * Added `debug.enable('project:*')` to browser variant [TooTallNate]
+  * Added padding to diff (moved it to the right)
+
+0.3.0 / 2012-01-26
+==================
+
+  * Added millisecond diff when isatty, otherwise UTC string
+
+0.2.0 / 2012-01-22
+==================
+
+  * Added wildcard support
+
+0.1.0 / 2011-12-02
+==================
+
+  * Added: remove colors unless stderr isatty [TooTallNate]
+
+0.0.1 / 2010-01-03
+==================
+
+  * Initial release
diff --git a/server/node_modules/debug/LICENSE b/server/node_modules/debug/LICENSE
new file mode 100644
index 0000000..658c933
--- /dev/null
+++ b/server/node_modules/debug/LICENSE
@@ -0,0 +1,19 @@
+(The MIT License)
+
+Copyright (c) 2014 TJ Holowaychuk <tj@vision-media.ca>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software 
+and associated documentation files (the 'Software'), to deal in the Software without restriction, 
+including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, 
+and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial 
+portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT 
+LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/debug/Makefile b/server/node_modules/debug/Makefile
new file mode 100644
index 0000000..584da8b
--- /dev/null
+++ b/server/node_modules/debug/Makefile
@@ -0,0 +1,50 @@
+# get Makefile directory name: http://stackoverflow.com/a/5982798/376773
+THIS_MAKEFILE_PATH:=$(word $(words $(MAKEFILE_LIST)),$(MAKEFILE_LIST))
+THIS_DIR:=$(shell cd $(dir $(THIS_MAKEFILE_PATH));pwd)
+
+# BIN directory
+BIN := $(THIS_DIR)/node_modules/.bin
+
+# Path
+PATH := node_modules/.bin:$(PATH)
+SHELL := /bin/bash
+
+# applications
+NODE ?= $(shell which node)
+YARN ?= $(shell which yarn)
+PKG ?= $(if $(YARN),$(YARN),$(NODE) $(shell which npm))
+BROWSERIFY ?= $(NODE) $(BIN)/browserify
+
+.FORCE:
+
+install: node_modules
+
+node_modules: package.json
+	@NODE_ENV= $(PKG) install
+	@touch node_modules
+
+lint: .FORCE
+	eslint browser.js debug.js index.js node.js
+
+test-node: .FORCE
+	istanbul cover node_modules/mocha/bin/_mocha -- test/**.js
+
+test-browser: .FORCE
+	mkdir -p dist
+
+	@$(BROWSERIFY) \
+		--standalone debug \
+		. > dist/debug.js
+
+	karma start --single-run
+	rimraf dist
+
+test: .FORCE
+	concurrently \
+		"make test-node" \
+		"make test-browser"
+
+coveralls:
+	cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js
+
+.PHONY: all install clean distclean
diff --git a/server/node_modules/debug/README.md b/server/node_modules/debug/README.md
new file mode 100644
index 0000000..f67be6b
--- /dev/null
+++ b/server/node_modules/debug/README.md
@@ -0,0 +1,312 @@
+# debug
+[![Build Status](https://travis-ci.org/visionmedia/debug.svg?branch=master)](https://travis-ci.org/visionmedia/debug)  [![Coverage Status](https://coveralls.io/repos/github/visionmedia/debug/badge.svg?branch=master)](https://coveralls.io/github/visionmedia/debug?branch=master)  [![Slack](https://visionmedia-community-slackin.now.sh/badge.svg)](https://visionmedia-community-slackin.now.sh/) [![OpenCollective](https://opencollective.com/debug/backers/badge.svg)](#backers) 
+[![OpenCollective](https://opencollective.com/debug/sponsors/badge.svg)](#sponsors)
+
+
+
+A tiny node.js debugging utility modelled after node core's debugging technique.
+
+**Discussion around the V3 API is under way [here](https://github.com/visionmedia/debug/issues/370)**
+
+## Installation
+
+```bash
+$ npm install debug
+```
+
+## Usage
+
+`debug` exposes a function; simply pass this function the name of your module, and it will return a decorated version of `console.error` for you to pass debug statements to. This will allow you to toggle the debug output for different parts of your module as well as the module as a whole.
+
+Example _app.js_:
+
+```js
+var debug = require('debug')('http')
+  , http = require('http')
+  , name = 'My App';
+
+// fake app
+
+debug('booting %s', name);
+
+http.createServer(function(req, res){
+  debug(req.method + ' ' + req.url);
+  res.end('hello\n');
+}).listen(3000, function(){
+  debug('listening');
+});
+
+// fake worker of some kind
+
+require('./worker');
+```
+
+Example _worker.js_:
+
+```js
+var debug = require('debug')('worker');
+
+setInterval(function(){
+  debug('doing some work');
+}, 1000);
+```
+
+ The __DEBUG__ environment variable is then used to enable these based on space or comma-delimited names. Here are some examples:
+
+  ![debug http and worker](http://f.cl.ly/items/18471z1H402O24072r1J/Screenshot.png)
+
+  ![debug worker](http://f.cl.ly/items/1X413v1a3M0d3C2c1E0i/Screenshot.png)
+
+#### Windows note
+
+ On Windows the environment variable is set using the `set` command.
+
+ ```cmd
+ set DEBUG=*,-not_this
+ ```
+
+ Note that PowerShell uses different syntax to set environment variables.
+
+ ```cmd
+ $env:DEBUG = "*,-not_this"
+  ```
+
+Then, run the program to be debugged as usual.
+
+## Millisecond diff
+
+  When actively developing an application it can be useful to see when the time spent between one `debug()` call and the next. Suppose for example you invoke `debug()` before requesting a resource, and after as well, the "+NNNms" will show you how much time was spent between calls.
+
+  ![](http://f.cl.ly/items/2i3h1d3t121M2Z1A3Q0N/Screenshot.png)
+
+  When stdout is not a TTY, `Date#toUTCString()` is used, making it more useful for logging the debug information as shown below:
+
+  ![](http://f.cl.ly/items/112H3i0e0o0P0a2Q2r11/Screenshot.png)
+
+## Conventions
+
+  If you're using this in one or more of your libraries, you _should_ use the name of your library so that developers may toggle debugging as desired without guessing names. If you have more than one debuggers you _should_ prefix them with your library name and use ":" to separate features. For example "bodyParser" from Connect would then be "connect:bodyParser".
+
+## Wildcards
+
+  The `*` character may be used as a wildcard. Suppose for example your library has debuggers named "connect:bodyParser", "connect:compress", "connect:session", instead of listing all three with `DEBUG=connect:bodyParser,connect:compress,connect:session`, you may simply do `DEBUG=connect:*`, or to run everything using this module simply use `DEBUG=*`.
+
+  You can also exclude specific debuggers by prefixing them with a "-" character.  For example, `DEBUG=*,-connect:*` would include all debuggers except those starting with "connect:".
+
+## Environment Variables
+
+  When running through Node.js, you can set a few environment variables that will
+  change the behavior of the debug logging:
+
+| Name      | Purpose                                         |
+|-----------|-------------------------------------------------|
+| `DEBUG`   | Enables/disables specific debugging namespaces. |
+| `DEBUG_COLORS`| Whether or not to use colors in the debug output. |
+| `DEBUG_DEPTH` | Object inspection depth. |
+| `DEBUG_SHOW_HIDDEN` | Shows hidden properties on inspected objects. |
+
+
+  __Note:__ The environment variables beginning with `DEBUG_` end up being
+  converted into an Options object that gets used with `%o`/`%O` formatters.
+  See the Node.js documentation for
+  [`util.inspect()`](https://nodejs.org/api/util.html#util_util_inspect_object_options)
+  for the complete list.
+
+## Formatters
+
+
+  Debug uses [printf-style](https://wikipedia.org/wiki/Printf_format_string) formatting. Below are the officially supported formatters:
+
+| Formatter | Representation |
+|-----------|----------------|
+| `%O`      | Pretty-print an Object on multiple lines. |
+| `%o`      | Pretty-print an Object all on a single line. |
+| `%s`      | String. |
+| `%d`      | Number (both integer and float). |
+| `%j`      | JSON. Replaced with the string '[Circular]' if the argument contains circular references. |
+| `%%`      | Single percent sign ('%'). This does not consume an argument. |
+
+### Custom formatters
+
+  You can add custom formatters by extending the `debug.formatters` object. For example, if you wanted to add support for rendering a Buffer as hex with `%h`, you could do something like:
+
+```js
+const createDebug = require('debug')
+createDebug.formatters.h = (v) => {
+  return v.toString('hex')
+}
+
+// …elsewhere
+const debug = createDebug('foo')
+debug('this is hex: %h', new Buffer('hello world'))
+//   foo this is hex: 68656c6c6f20776f726c6421 +0ms
+```
+
+## Browser support
+  You can build a browser-ready script using [browserify](https://github.com/substack/node-browserify),
+  or just use the [browserify-as-a-service](https://wzrd.in/) [build](https://wzrd.in/standalone/debug@latest),
+  if you don't want to build it yourself.
+
+  Debug's enable state is currently persisted by `localStorage`.
+  Consider the situation shown below where you have `worker:a` and `worker:b`,
+  and wish to debug both. You can enable this using `localStorage.debug`:
+
+```js
+localStorage.debug = 'worker:*'
+```
+
+And then refresh the page.
+
+```js
+a = debug('worker:a');
+b = debug('worker:b');
+
+setInterval(function(){
+  a('doing some work');
+}, 1000);
+
+setInterval(function(){
+  b('doing some work');
+}, 1200);
+```
+
+#### Web Inspector Colors
+
+  Colors are also enabled on "Web Inspectors" that understand the `%c` formatting
+  option. These are WebKit web inspectors, Firefox ([since version
+  31](https://hacks.mozilla.org/2014/05/editable-box-model-multiple-selection-sublime-text-keys-much-more-firefox-developer-tools-episode-31/))
+  and the Firebug plugin for Firefox (any version).
+
+  Colored output looks something like:
+
+  ![](https://cloud.githubusercontent.com/assets/71256/3139768/b98c5fd8-e8ef-11e3-862a-f7253b6f47c6.png)
+
+
+## Output streams
+
+  By default `debug` will log to stderr, however this can be configured per-namespace by overriding the `log` method:
+
+Example _stdout.js_:
+
+```js
+var debug = require('debug');
+var error = debug('app:error');
+
+// by default stderr is used
+error('goes to stderr!');
+
+var log = debug('app:log');
+// set this namespace to log via console.log
+log.log = console.log.bind(console); // don't forget to bind to console!
+log('goes to stdout');
+error('still goes to stderr!');
+
+// set all output to go via console.info
+// overrides all per-namespace log settings
+debug.log = console.info.bind(console);
+error('now goes to stdout via console.info');
+log('still goes to stdout, but via console.info now');
+```
+
+
+## Authors
+
+ - TJ Holowaychuk
+ - Nathan Rajlich
+ - Andrew Rhyne
+ 
+## Backers
+
+Support us with a monthly donation and help us continue our activities. [[Become a backer](https://opencollective.com/debug#backer)]
+
+<a href="https://opencollective.com/debug/backer/0/website" target="_blank"><img src="https://opencollective.com/debug/backer/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/1/website" target="_blank"><img src="https://opencollective.com/debug/backer/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/2/website" target="_blank"><img src="https://opencollective.com/debug/backer/2/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/3/website" target="_blank"><img src="https://opencollective.com/debug/backer/3/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/4/website" target="_blank"><img src="https://opencollective.com/debug/backer/4/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/5/website" target="_blank"><img src="https://opencollective.com/debug/backer/5/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/6/website" target="_blank"><img src="https://opencollective.com/debug/backer/6/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/7/website" target="_blank"><img src="https://opencollective.com/debug/backer/7/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/8/website" target="_blank"><img src="https://opencollective.com/debug/backer/8/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/9/website" target="_blank"><img src="https://opencollective.com/debug/backer/9/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/10/website" target="_blank"><img src="https://opencollective.com/debug/backer/10/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/11/website" target="_blank"><img src="https://opencollective.com/debug/backer/11/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/12/website" target="_blank"><img src="https://opencollective.com/debug/backer/12/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/13/website" target="_blank"><img src="https://opencollective.com/debug/backer/13/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/14/website" target="_blank"><img src="https://opencollective.com/debug/backer/14/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/15/website" target="_blank"><img src="https://opencollective.com/debug/backer/15/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/16/website" target="_blank"><img src="https://opencollective.com/debug/backer/16/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/17/website" target="_blank"><img src="https://opencollective.com/debug/backer/17/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/18/website" target="_blank"><img src="https://opencollective.com/debug/backer/18/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/19/website" target="_blank"><img src="https://opencollective.com/debug/backer/19/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/20/website" target="_blank"><img src="https://opencollective.com/debug/backer/20/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/21/website" target="_blank"><img src="https://opencollective.com/debug/backer/21/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/22/website" target="_blank"><img src="https://opencollective.com/debug/backer/22/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/23/website" target="_blank"><img src="https://opencollective.com/debug/backer/23/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/24/website" target="_blank"><img src="https://opencollective.com/debug/backer/24/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/25/website" target="_blank"><img src="https://opencollective.com/debug/backer/25/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/26/website" target="_blank"><img src="https://opencollective.com/debug/backer/26/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/27/website" target="_blank"><img src="https://opencollective.com/debug/backer/27/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/28/website" target="_blank"><img src="https://opencollective.com/debug/backer/28/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/29/website" target="_blank"><img src="https://opencollective.com/debug/backer/29/avatar.svg"></a>
+
+
+## Sponsors
+
+Become a sponsor and get your logo on our README on Github with a link to your site. [[Become a sponsor](https://opencollective.com/debug#sponsor)]
+
+<a href="https://opencollective.com/debug/sponsor/0/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/1/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/2/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/2/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/3/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/3/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/4/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/4/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/5/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/5/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/6/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/6/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/7/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/7/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/8/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/8/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/9/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/9/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/10/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/10/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/11/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/11/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/12/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/12/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/13/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/13/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/14/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/14/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/15/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/15/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/16/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/16/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/17/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/17/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/18/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/18/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/19/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/19/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/20/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/20/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/21/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/21/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/22/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/22/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/23/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/23/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/24/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/24/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/25/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/25/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/26/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/26/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/27/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/27/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/28/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/28/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/29/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/29/avatar.svg"></a>
+
+## License
+
+(The MIT License)
+
+Copyright (c) 2014-2016 TJ Holowaychuk <tj@vision-media.ca>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/debug/component.json b/server/node_modules/debug/component.json
new file mode 100644
index 0000000..9de2641
--- /dev/null
+++ b/server/node_modules/debug/component.json
@@ -0,0 +1,19 @@
+{
+  "name": "debug",
+  "repo": "visionmedia/debug",
+  "description": "small debugging utility",
+  "version": "2.6.9",
+  "keywords": [
+    "debug",
+    "log",
+    "debugger"
+  ],
+  "main": "src/browser.js",
+  "scripts": [
+    "src/browser.js",
+    "src/debug.js"
+  ],
+  "dependencies": {
+    "rauchg/ms.js": "0.7.1"
+  }
+}
diff --git a/server/node_modules/debug/karma.conf.js b/server/node_modules/debug/karma.conf.js
new file mode 100644
index 0000000..103a82d
--- /dev/null
+++ b/server/node_modules/debug/karma.conf.js
@@ -0,0 +1,70 @@
+// Karma configuration
+// Generated on Fri Dec 16 2016 13:09:51 GMT+0000 (UTC)
+
+module.exports = function(config) {
+  config.set({
+
+    // base path that will be used to resolve all patterns (eg. files, exclude)
+    basePath: '',
+
+
+    // frameworks to use
+    // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
+    frameworks: ['mocha', 'chai', 'sinon'],
+
+
+    // list of files / patterns to load in the browser
+    files: [
+      'dist/debug.js',
+      'test/*spec.js'
+    ],
+
+
+    // list of files to exclude
+    exclude: [
+      'src/node.js'
+    ],
+
+
+    // preprocess matching files before serving them to the browser
+    // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
+    preprocessors: {
+    },
+
+    // test results reporter to use
+    // possible values: 'dots', 'progress'
+    // available reporters: https://npmjs.org/browse/keyword/karma-reporter
+    reporters: ['progress'],
+
+
+    // web server port
+    port: 9876,
+
+
+    // enable / disable colors in the output (reporters and logs)
+    colors: true,
+
+
+    // level of logging
+    // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
+    logLevel: config.LOG_INFO,
+
+
+    // enable / disable watching file and executing tests whenever any file changes
+    autoWatch: true,
+
+
+    // start these browsers
+    // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
+    browsers: ['PhantomJS'],
+
+
+    // Continuous Integration mode
+    // if true, Karma captures browsers, runs the tests and exits
+    singleRun: false,
+
+    // Concurrency level
+    // how many browser should be started simultaneous
+    concurrency: Infinity
+  })
+}
diff --git a/server/node_modules/debug/node.js b/server/node_modules/debug/node.js
new file mode 100644
index 0000000..7fc36fe
--- /dev/null
+++ b/server/node_modules/debug/node.js
@@ -0,0 +1 @@
+module.exports = require('./src/node');
diff --git a/server/node_modules/debug/package.json b/server/node_modules/debug/package.json
new file mode 100644
index 0000000..dc787ba
--- /dev/null
+++ b/server/node_modules/debug/package.json
@@ -0,0 +1,49 @@
+{
+  "name": "debug",
+  "version": "2.6.9",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/visionmedia/debug.git"
+  },
+  "description": "small debugging utility",
+  "keywords": [
+    "debug",
+    "log",
+    "debugger"
+  ],
+  "author": "TJ Holowaychuk <tj@vision-media.ca>",
+  "contributors": [
+    "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io)",
+    "Andrew Rhyne <rhyneandrew@gmail.com>"
+  ],
+  "license": "MIT",
+  "dependencies": {
+    "ms": "2.0.0"
+  },
+  "devDependencies": {
+    "browserify": "9.0.3",
+    "chai": "^3.5.0",
+    "concurrently": "^3.1.0",
+    "coveralls": "^2.11.15",
+    "eslint": "^3.12.1",
+    "istanbul": "^0.4.5",
+    "karma": "^1.3.0",
+    "karma-chai": "^0.1.0",
+    "karma-mocha": "^1.3.0",
+    "karma-phantomjs-launcher": "^1.0.2",
+    "karma-sinon": "^1.0.5",
+    "mocha": "^3.2.0",
+    "mocha-lcov-reporter": "^1.2.0",
+    "rimraf": "^2.5.4",
+    "sinon": "^1.17.6",
+    "sinon-chai": "^2.8.0"
+  },
+  "main": "./src/index.js",
+  "browser": "./src/browser.js",
+  "component": {
+    "scripts": {
+      "debug/index.js": "browser.js",
+      "debug/debug.js": "debug.js"
+    }
+  }
+}
diff --git a/server/node_modules/debug/src/browser.js b/server/node_modules/debug/src/browser.js
new file mode 100644
index 0000000..7106924
--- /dev/null
+++ b/server/node_modules/debug/src/browser.js
@@ -0,0 +1,185 @@
+/**
+ * This is the web browser implementation of `debug()`.
+ *
+ * Expose `debug()` as the module.
+ */
+
+exports = module.exports = require('./debug');
+exports.log = log;
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+exports.storage = 'undefined' != typeof chrome
+               && 'undefined' != typeof chrome.storage
+                  ? chrome.storage.local
+                  : localstorage();
+
+/**
+ * Colors.
+ */
+
+exports.colors = [
+  'lightseagreen',
+  'forestgreen',
+  'goldenrod',
+  'dodgerblue',
+  'darkorchid',
+  'crimson'
+];
+
+/**
+ * Currently only WebKit-based Web Inspectors, Firefox >= v31,
+ * and the Firebug extension (any Firefox version) are known
+ * to support "%c" CSS customizations.
+ *
+ * TODO: add a `localStorage` variable to explicitly enable/disable colors
+ */
+
+function useColors() {
+  // NB: In an Electron preload script, document will be defined but not fully
+  // initialized. Since we know we're in Chrome, we'll just detect this case
+  // explicitly
+  if (typeof window !== 'undefined' && window.process && window.process.type === 'renderer') {
+    return true;
+  }
+
+  // is webkit? http://stackoverflow.com/a/16459606/376773
+  // document is undefined in react-native: https://github.com/facebook/react-native/pull/1632
+  return (typeof document !== 'undefined' && document.documentElement && document.documentElement.style && document.documentElement.style.WebkitAppearance) ||
+    // is firebug? http://stackoverflow.com/a/398120/376773
+    (typeof window !== 'undefined' && window.console && (window.console.firebug || (window.console.exception && window.console.table))) ||
+    // is firefox >= v31?
+    // https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
+    (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/) && parseInt(RegExp.$1, 10) >= 31) ||
+    // double check webkit in userAgent just in case we are in a worker
+    (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/applewebkit\/(\d+)/));
+}
+
+/**
+ * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
+ */
+
+exports.formatters.j = function(v) {
+  try {
+    return JSON.stringify(v);
+  } catch (err) {
+    return '[UnexpectedJSONParseError]: ' + err.message;
+  }
+};
+
+
+/**
+ * Colorize log arguments if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+  var useColors = this.useColors;
+
+  args[0] = (useColors ? '%c' : '')
+    + this.namespace
+    + (useColors ? ' %c' : ' ')
+    + args[0]
+    + (useColors ? '%c ' : ' ')
+    + '+' + exports.humanize(this.diff);
+
+  if (!useColors) return;
+
+  var c = 'color: ' + this.color;
+  args.splice(1, 0, c, 'color: inherit')
+
+  // the final "%c" is somewhat tricky, because there could be other
+  // arguments passed either before or after the %c, so we need to
+  // figure out the correct index to insert the CSS into
+  var index = 0;
+  var lastC = 0;
+  args[0].replace(/%[a-zA-Z%]/g, function(match) {
+    if ('%%' === match) return;
+    index++;
+    if ('%c' === match) {
+      // we only are interested in the *last* %c
+      // (the user may have provided their own)
+      lastC = index;
+    }
+  });
+
+  args.splice(lastC, 0, c);
+}
+
+/**
+ * Invokes `console.log()` when available.
+ * No-op when `console.log` is not a "function".
+ *
+ * @api public
+ */
+
+function log() {
+  // this hackery is required for IE8/9, where
+  // the `console.log` function doesn't have 'apply'
+  return 'object' === typeof console
+    && console.log
+    && Function.prototype.apply.call(console.log, console, arguments);
+}
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+
+function save(namespaces) {
+  try {
+    if (null == namespaces) {
+      exports.storage.removeItem('debug');
+    } else {
+      exports.storage.debug = namespaces;
+    }
+  } catch(e) {}
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+
+function load() {
+  var r;
+  try {
+    r = exports.storage.debug;
+  } catch(e) {}
+
+  // If debug isn't set in LS, and we're in Electron, try to load $DEBUG
+  if (!r && typeof process !== 'undefined' && 'env' in process) {
+    r = process.env.DEBUG;
+  }
+
+  return r;
+}
+
+/**
+ * Enable namespaces listed in `localStorage.debug` initially.
+ */
+
+exports.enable(load());
+
+/**
+ * Localstorage attempts to return the localstorage.
+ *
+ * This is necessary because safari throws
+ * when a user disables cookies/localstorage
+ * and you attempt to access it.
+ *
+ * @return {LocalStorage}
+ * @api private
+ */
+
+function localstorage() {
+  try {
+    return window.localStorage;
+  } catch (e) {}
+}
diff --git a/server/node_modules/debug/src/debug.js b/server/node_modules/debug/src/debug.js
new file mode 100644
index 0000000..6a5e3fc
--- /dev/null
+++ b/server/node_modules/debug/src/debug.js
@@ -0,0 +1,202 @@
+
+/**
+ * This is the common logic for both the Node.js and web browser
+ * implementations of `debug()`.
+ *
+ * Expose `debug()` as the module.
+ */
+
+exports = module.exports = createDebug.debug = createDebug['default'] = createDebug;
+exports.coerce = coerce;
+exports.disable = disable;
+exports.enable = enable;
+exports.enabled = enabled;
+exports.humanize = require('ms');
+
+/**
+ * The currently active debug mode names, and names to skip.
+ */
+
+exports.names = [];
+exports.skips = [];
+
+/**
+ * Map of special "%n" handling functions, for the debug "format" argument.
+ *
+ * Valid key names are a single, lower or upper-case letter, i.e. "n" and "N".
+ */
+
+exports.formatters = {};
+
+/**
+ * Previous log timestamp.
+ */
+
+var prevTime;
+
+/**
+ * Select a color.
+ * @param {String} namespace
+ * @return {Number}
+ * @api private
+ */
+
+function selectColor(namespace) {
+  var hash = 0, i;
+
+  for (i in namespace) {
+    hash  = ((hash << 5) - hash) + namespace.charCodeAt(i);
+    hash |= 0; // Convert to 32bit integer
+  }
+
+  return exports.colors[Math.abs(hash) % exports.colors.length];
+}
+
+/**
+ * Create a debugger with the given `namespace`.
+ *
+ * @param {String} namespace
+ * @return {Function}
+ * @api public
+ */
+
+function createDebug(namespace) {
+
+  function debug() {
+    // disabled?
+    if (!debug.enabled) return;
+
+    var self = debug;
+
+    // set `diff` timestamp
+    var curr = +new Date();
+    var ms = curr - (prevTime || curr);
+    self.diff = ms;
+    self.prev = prevTime;
+    self.curr = curr;
+    prevTime = curr;
+
+    // turn the `arguments` into a proper Array
+    var args = new Array(arguments.length);
+    for (var i = 0; i < args.length; i++) {
+      args[i] = arguments[i];
+    }
+
+    args[0] = exports.coerce(args[0]);
+
+    if ('string' !== typeof args[0]) {
+      // anything else let's inspect with %O
+      args.unshift('%O');
+    }
+
+    // apply any `formatters` transformations
+    var index = 0;
+    args[0] = args[0].replace(/%([a-zA-Z%])/g, function(match, format) {
+      // if we encounter an escaped % then don't increase the array index
+      if (match === '%%') return match;
+      index++;
+      var formatter = exports.formatters[format];
+      if ('function' === typeof formatter) {
+        var val = args[index];
+        match = formatter.call(self, val);
+
+        // now we need to remove `args[index]` since it's inlined in the `format`
+        args.splice(index, 1);
+        index--;
+      }
+      return match;
+    });
+
+    // apply env-specific formatting (colors, etc.)
+    exports.formatArgs.call(self, args);
+
+    var logFn = debug.log || exports.log || console.log.bind(console);
+    logFn.apply(self, args);
+  }
+
+  debug.namespace = namespace;
+  debug.enabled = exports.enabled(namespace);
+  debug.useColors = exports.useColors();
+  debug.color = selectColor(namespace);
+
+  // env-specific initialization logic for debug instances
+  if ('function' === typeof exports.init) {
+    exports.init(debug);
+  }
+
+  return debug;
+}
+
+/**
+ * Enables a debug mode by namespaces. This can include modes
+ * separated by a colon and wildcards.
+ *
+ * @param {String} namespaces
+ * @api public
+ */
+
+function enable(namespaces) {
+  exports.save(namespaces);
+
+  exports.names = [];
+  exports.skips = [];
+
+  var split = (typeof namespaces === 'string' ? namespaces : '').split(/[\s,]+/);
+  var len = split.length;
+
+  for (var i = 0; i < len; i++) {
+    if (!split[i]) continue; // ignore empty strings
+    namespaces = split[i].replace(/\*/g, '.*?');
+    if (namespaces[0] === '-') {
+      exports.skips.push(new RegExp('^' + namespaces.substr(1) + '$'));
+    } else {
+      exports.names.push(new RegExp('^' + namespaces + '$'));
+    }
+  }
+}
+
+/**
+ * Disable debug output.
+ *
+ * @api public
+ */
+
+function disable() {
+  exports.enable('');
+}
+
+/**
+ * Returns true if the given mode name is enabled, false otherwise.
+ *
+ * @param {String} name
+ * @return {Boolean}
+ * @api public
+ */
+
+function enabled(name) {
+  var i, len;
+  for (i = 0, len = exports.skips.length; i < len; i++) {
+    if (exports.skips[i].test(name)) {
+      return false;
+    }
+  }
+  for (i = 0, len = exports.names.length; i < len; i++) {
+    if (exports.names[i].test(name)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+/**
+ * Coerce `val`.
+ *
+ * @param {Mixed} val
+ * @return {Mixed}
+ * @api private
+ */
+
+function coerce(val) {
+  if (val instanceof Error) return val.stack || val.message;
+  return val;
+}
diff --git a/server/node_modules/debug/src/index.js b/server/node_modules/debug/src/index.js
new file mode 100644
index 0000000..e12cf4d
--- /dev/null
+++ b/server/node_modules/debug/src/index.js
@@ -0,0 +1,10 @@
+/**
+ * Detect Electron renderer process, which is node, but we should
+ * treat as a browser.
+ */
+
+if (typeof process !== 'undefined' && process.type === 'renderer') {
+  module.exports = require('./browser.js');
+} else {
+  module.exports = require('./node.js');
+}
diff --git a/server/node_modules/debug/src/inspector-log.js b/server/node_modules/debug/src/inspector-log.js
new file mode 100644
index 0000000..60ea6c0
--- /dev/null
+++ b/server/node_modules/debug/src/inspector-log.js
@@ -0,0 +1,15 @@
+module.exports = inspectorLog;
+
+// black hole
+const nullStream = new (require('stream').Writable)();
+nullStream._write = () => {};
+
+/**
+ * Outputs a `console.log()` to the Node.js Inspector console *only*.
+ */
+function inspectorLog() {
+  const stdout = console._stdout;
+  console._stdout = nullStream;
+  console.log.apply(console, arguments);
+  console._stdout = stdout;
+}
diff --git a/server/node_modules/debug/src/node.js b/server/node_modules/debug/src/node.js
new file mode 100644
index 0000000..b15109c
--- /dev/null
+++ b/server/node_modules/debug/src/node.js
@@ -0,0 +1,248 @@
+/**
+ * Module dependencies.
+ */
+
+var tty = require('tty');
+var util = require('util');
+
+/**
+ * This is the Node.js implementation of `debug()`.
+ *
+ * Expose `debug()` as the module.
+ */
+
+exports = module.exports = require('./debug');
+exports.init = init;
+exports.log = log;
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+
+/**
+ * Colors.
+ */
+
+exports.colors = [6, 2, 3, 4, 5, 1];
+
+/**
+ * Build up the default `inspectOpts` object from the environment variables.
+ *
+ *   $ DEBUG_COLORS=no DEBUG_DEPTH=10 DEBUG_SHOW_HIDDEN=enabled node script.js
+ */
+
+exports.inspectOpts = Object.keys(process.env).filter(function (key) {
+  return /^debug_/i.test(key);
+}).reduce(function (obj, key) {
+  // camel-case
+  var prop = key
+    .substring(6)
+    .toLowerCase()
+    .replace(/_([a-z])/g, function (_, k) { return k.toUpperCase() });
+
+  // coerce string value into JS value
+  var val = process.env[key];
+  if (/^(yes|on|true|enabled)$/i.test(val)) val = true;
+  else if (/^(no|off|false|disabled)$/i.test(val)) val = false;
+  else if (val === 'null') val = null;
+  else val = Number(val);
+
+  obj[prop] = val;
+  return obj;
+}, {});
+
+/**
+ * The file descriptor to write the `debug()` calls to.
+ * Set the `DEBUG_FD` env variable to override with another value. i.e.:
+ *
+ *   $ DEBUG_FD=3 node script.js 3>debug.log
+ */
+
+var fd = parseInt(process.env.DEBUG_FD, 10) || 2;
+
+if (1 !== fd && 2 !== fd) {
+  util.deprecate(function(){}, 'except for stderr(2) and stdout(1), any other usage of DEBUG_FD is deprecated. Override debug.log if you want to use a different log function (https://git.io/debug_fd)')()
+}
+
+var stream = 1 === fd ? process.stdout :
+             2 === fd ? process.stderr :
+             createWritableStdioStream(fd);
+
+/**
+ * Is stdout a TTY? Colored output is enabled when `true`.
+ */
+
+function useColors() {
+  return 'colors' in exports.inspectOpts
+    ? Boolean(exports.inspectOpts.colors)
+    : tty.isatty(fd);
+}
+
+/**
+ * Map %o to `util.inspect()`, all on a single line.
+ */
+
+exports.formatters.o = function(v) {
+  this.inspectOpts.colors = this.useColors;
+  return util.inspect(v, this.inspectOpts)
+    .split('\n').map(function(str) {
+      return str.trim()
+    }).join(' ');
+};
+
+/**
+ * Map %o to `util.inspect()`, allowing multiple lines if needed.
+ */
+
+exports.formatters.O = function(v) {
+  this.inspectOpts.colors = this.useColors;
+  return util.inspect(v, this.inspectOpts);
+};
+
+/**
+ * Adds ANSI color escape codes if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+  var name = this.namespace;
+  var useColors = this.useColors;
+
+  if (useColors) {
+    var c = this.color;
+    var prefix = '  \u001b[3' + c + ';1m' + name + ' ' + '\u001b[0m';
+
+    args[0] = prefix + args[0].split('\n').join('\n' + prefix);
+    args.push('\u001b[3' + c + 'm+' + exports.humanize(this.diff) + '\u001b[0m');
+  } else {
+    args[0] = new Date().toUTCString()
+      + ' ' + name + ' ' + args[0];
+  }
+}
+
+/**
+ * Invokes `util.format()` with the specified arguments and writes to `stream`.
+ */
+
+function log() {
+  return stream.write(util.format.apply(util, arguments) + '\n');
+}
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+
+function save(namespaces) {
+  if (null == namespaces) {
+    // If you set a process.env field to null or undefined, it gets cast to the
+    // string 'null' or 'undefined'. Just delete instead.
+    delete process.env.DEBUG;
+  } else {
+    process.env.DEBUG = namespaces;
+  }
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+
+function load() {
+  return process.env.DEBUG;
+}
+
+/**
+ * Copied from `node/src/node.js`.
+ *
+ * XXX: It's lame that node doesn't expose this API out-of-the-box. It also
+ * relies on the undocumented `tty_wrap.guessHandleType()` which is also lame.
+ */
+
+function createWritableStdioStream (fd) {
+  var stream;
+  var tty_wrap = process.binding('tty_wrap');
+
+  // Note stream._type is used for test-module-load-list.js
+
+  switch (tty_wrap.guessHandleType(fd)) {
+    case 'TTY':
+      stream = new tty.WriteStream(fd);
+      stream._type = 'tty';
+
+      // Hack to have stream not keep the event loop alive.
+      // See https://github.com/joyent/node/issues/1726
+      if (stream._handle && stream._handle.unref) {
+        stream._handle.unref();
+      }
+      break;
+
+    case 'FILE':
+      var fs = require('fs');
+      stream = new fs.SyncWriteStream(fd, { autoClose: false });
+      stream._type = 'fs';
+      break;
+
+    case 'PIPE':
+    case 'TCP':
+      var net = require('net');
+      stream = new net.Socket({
+        fd: fd,
+        readable: false,
+        writable: true
+      });
+
+      // FIXME Should probably have an option in net.Socket to create a
+      // stream from an existing fd which is writable only. But for now
+      // we'll just add this hack and set the `readable` member to false.
+      // Test: ./node test/fixtures/echo.js < /etc/passwd
+      stream.readable = false;
+      stream.read = null;
+      stream._type = 'pipe';
+
+      // FIXME Hack to have stream not keep the event loop alive.
+      // See https://github.com/joyent/node/issues/1726
+      if (stream._handle && stream._handle.unref) {
+        stream._handle.unref();
+      }
+      break;
+
+    default:
+      // Probably an error on in uv_guess_handle()
+      throw new Error('Implement me. Unknown stream file type!');
+  }
+
+  // For supporting legacy API we put the FD here.
+  stream.fd = fd;
+
+  stream._isStdio = true;
+
+  return stream;
+}
+
+/**
+ * Init logic for `debug` instances.
+ *
+ * Create a new `inspectOpts` object in case `useColors` is set
+ * differently for a particular `debug` instance.
+ */
+
+function init (debug) {
+  debug.inspectOpts = {};
+
+  var keys = Object.keys(exports.inspectOpts);
+  for (var i = 0; i < keys.length; i++) {
+    debug.inspectOpts[keys[i]] = exports.inspectOpts[keys[i]];
+  }
+}
+
+/**
+ * Enable namespaces listed in `process.env.DEBUG` initially.
+ */
+
+exports.enable(load());
diff --git a/server/node_modules/decompress-response/index.d.ts b/server/node_modules/decompress-response/index.d.ts
new file mode 100644
index 0000000..c0be175
--- /dev/null
+++ b/server/node_modules/decompress-response/index.d.ts
@@ -0,0 +1,22 @@
+/// <reference types="node"/>
+import {IncomingMessage} from 'http';
+
+/**
+Decompress a HTTP response if needed.
+
+@param response - The HTTP incoming stream with compressed data.
+@returns The decompressed HTTP response stream.
+
+@example
+```
+import {http} from 'http';
+import decompressResponse = require('decompress-response');
+
+http.get('https://sindresorhus.com', response => {
+	response = decompressResponse(response);
+});
+```
+*/
+declare function decompressResponse(response: IncomingMessage): IncomingMessage;
+
+export = decompressResponse;
diff --git a/server/node_modules/decompress-response/index.js b/server/node_modules/decompress-response/index.js
new file mode 100644
index 0000000..c861036
--- /dev/null
+++ b/server/node_modules/decompress-response/index.js
@@ -0,0 +1,58 @@
+'use strict';
+const {Transform, PassThrough} = require('stream');
+const zlib = require('zlib');
+const mimicResponse = require('mimic-response');
+
+module.exports = response => {
+	const contentEncoding = (response.headers['content-encoding'] || '').toLowerCase();
+
+	if (!['gzip', 'deflate', 'br'].includes(contentEncoding)) {
+		return response;
+	}
+
+	// TODO: Remove this when targeting Node.js 12.
+	const isBrotli = contentEncoding === 'br';
+	if (isBrotli && typeof zlib.createBrotliDecompress !== 'function') {
+		response.destroy(new Error('Brotli is not supported on Node.js < 12'));
+		return response;
+	}
+
+	let isEmpty = true;
+
+	const checker = new Transform({
+		transform(data, _encoding, callback) {
+			isEmpty = false;
+
+			callback(null, data);
+		},
+
+		flush(callback) {
+			callback();
+		}
+	});
+
+	const finalStream = new PassThrough({
+		autoDestroy: false,
+		destroy(error, callback) {
+			response.destroy();
+
+			callback(error);
+		}
+	});
+
+	const decompressStream = isBrotli ? zlib.createBrotliDecompress() : zlib.createUnzip();
+
+	decompressStream.once('error', error => {
+		if (isEmpty && !response.readable) {
+			finalStream.end();
+			return;
+		}
+
+		finalStream.destroy(error);
+	});
+
+	mimicResponse(response, finalStream);
+	response.pipe(checker).pipe(decompressStream).pipe(finalStream);
+
+	return finalStream;
+};
diff --git a/server/node_modules/decompress-response/license b/server/node_modules/decompress-response/license
new file mode 100644
index 0000000..fa7ceba
--- /dev/null
+++ b/server/node_modules/decompress-response/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/decompress-response/package.json b/server/node_modules/decompress-response/package.json
new file mode 100644
index 0000000..57df889
--- /dev/null
+++ b/server/node_modules/decompress-response/package.json
@@ -0,0 +1,56 @@
+{
+	"name": "decompress-response",
+	"version": "6.0.0",
+	"description": "Decompress a HTTP response if needed",
+	"license": "MIT",
+	"repository": "sindresorhus/decompress-response",
+	"funding": "https://github.com/sponsors/sindresorhus",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "https://sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=10"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"decompress",
+		"response",
+		"http",
+		"https",
+		"zlib",
+		"gzip",
+		"zip",
+		"deflate",
+		"unzip",
+		"ungzip",
+		"incoming",
+		"message",
+		"stream",
+		"compressed",
+		"brotli"
+	],
+	"dependencies": {
+		"mimic-response": "^3.1.0"
+	},
+	"devDependencies": {
+		"@types/node": "^14.0.1",
+		"ava": "^2.2.0",
+		"get-stream": "^5.0.0",
+		"pify": "^5.0.0",
+		"tsd": "^0.11.0",
+		"xo": "^0.30.0"
+	},
+	"xo": {
+		"rules": {
+			"@typescript-eslint/prefer-readonly-parameter-types": "off"
+		}
+	}
+}
diff --git a/server/node_modules/decompress-response/readme.md b/server/node_modules/decompress-response/readme.md
new file mode 100644
index 0000000..58523ef
--- /dev/null
+++ b/server/node_modules/decompress-response/readme.md
@@ -0,0 +1,48 @@
+# decompress-response [![Build Status](https://travis-ci.com/sindresorhus/decompress-response.svg?branch=master)](https://travis-ci.com/sindresorhus/decompress-response)
+
+> Decompress a HTTP response if needed
+
+Decompresses the [response](https://nodejs.org/api/http.html#http_class_http_incomingmessage) from [`http.request`](https://nodejs.org/api/http.html#http_http_request_options_callback) if it's gzipped, deflated or compressed with Brotli, otherwise just passes it through.
+
+Used by [`got`](https://github.com/sindresorhus/got).
+
+## Install
+
+```
+$ npm install decompress-response
+```
+
+## Usage
+
+```js
+const http = require('http');
+const decompressResponse = require('decompress-response');
+
+http.get('https://sindresorhus.com', response => {
+	response = decompressResponse(response);
+});
+```
+
+## API
+
+### decompressResponse(response)
+
+Returns the decompressed HTTP response stream.
+
+#### response
+
+Type: [`http.IncomingMessage`](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
+
+The HTTP incoming stream with compressed data.
+
+---
+
+<div align="center">
+	<b>
+		<a href="https://tidelift.com/subscription/pkg/npm-decompress-response?utm_source=npm-decompress-response&utm_medium=referral&utm_campaign=readme">Get professional support for this package with a Tidelift subscription</a>
+	</b>
+	<br>
+	<sub>
+		Tidelift helps make open source sustainable for maintainers while giving companies<br>assurances about security, maintenance, and licensing for their dependencies.
+	</sub>
+</div>
diff --git a/server/node_modules/deep-extend/CHANGELOG.md b/server/node_modules/deep-extend/CHANGELOG.md
new file mode 100644
index 0000000..dd13ec1
--- /dev/null
+++ b/server/node_modules/deep-extend/CHANGELOG.md
@@ -0,0 +1,46 @@
+Changelog
+=========
+
+v0.6.0
+------
+
+- Updated "devDependencies" versions to fix vulnerability alerts
+- Dropped support of io.js and node.js v0.12.x and lower since new versions of
+  "devDependencies" couldn't work with those old node.js versions
+  (minimal supported version of node.js now is v4.0.0)
+
+v0.5.1
+------
+
+- Fix prototype pollution vulnerability (thanks to @mwakerman for the PR)
+- Avoid using deprecated Buffer API (thanks to @ChALkeR for the PR)
+
+v0.5.0
+------
+
+- Auto-testing provided by Travis CI;
+- Support older Node.JS versions (`v0.11.x` and `v0.10.x`);
+- Removed tests files from npm package.
+
+v0.4.2
+------
+
+- Fix for `null` as an argument.
+
+v0.4.1
+------
+
+- Removed test code from <b>npm</b> package
+  ([see pull request #21](https://github.com/unclechu/node-deep-extend/pull/21));
+- Increased minimal version of Node from `0.4.0` to `0.12.0`
+  (because can't run tests on lesser version anyway).
+
+v0.4.0
+------
+
+- **WARNING!** Broken backward compatibility with `v0.3.x`;
+- Fixed bug with extending arrays instead of cloning;
+- Deep cloning for arrays;
+- Check for own property;
+- Fixed some documentation issues;
+- Strict JS mode.
diff --git a/server/node_modules/deep-extend/LICENSE b/server/node_modules/deep-extend/LICENSE
new file mode 100644
index 0000000..5c58916
--- /dev/null
+++ b/server/node_modules/deep-extend/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2013-2018, Viacheslav Lotsmanov
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/deep-extend/README.md b/server/node_modules/deep-extend/README.md
new file mode 100644
index 0000000..67c7fc0
--- /dev/null
+++ b/server/node_modules/deep-extend/README.md
@@ -0,0 +1,91 @@
+Deep Extend
+===========
+
+Recursive object extending.
+
+[![Build Status](https://api.travis-ci.org/unclechu/node-deep-extend.svg?branch=master)](https://travis-ci.org/unclechu/node-deep-extend)
+
+[![NPM](https://nodei.co/npm/deep-extend.png?downloads=true&downloadRank=true&stars=true)](https://nodei.co/npm/deep-extend/)
+
+Install
+-------
+
+```bash
+$ npm install deep-extend
+```
+
+Usage
+-----
+
+```javascript
+var deepExtend = require('deep-extend');
+var obj1 = {
+  a: 1,
+  b: 2,
+  d: {
+    a: 1,
+    b: [],
+    c: { test1: 123, test2: 321 }
+  },
+  f: 5,
+  g: 123,
+  i: 321,
+  j: [1, 2]
+};
+var obj2 = {
+  b: 3,
+  c: 5,
+  d: {
+    b: { first: 'one', second: 'two' },
+    c: { test2: 222 }
+  },
+  e: { one: 1, two: 2 },
+  f: [],
+  g: (void 0),
+  h: /abc/g,
+  i: null,
+  j: [3, 4]
+};
+
+deepExtend(obj1, obj2);
+
+console.log(obj1);
+/*
+{ a: 1,
+  b: 3,
+  d:
+   { a: 1,
+     b: { first: 'one', second: 'two' },
+     c: { test1: 123, test2: 222 } },
+  f: [],
+  g: undefined,
+  c: 5,
+  e: { one: 1, two: 2 },
+  h: /abc/g,
+  i: null,
+  j: [3, 4] }
+*/
+```
+
+Unit testing
+------------
+
+```bash
+$ npm test
+```
+
+Changelog
+---------
+
+[CHANGELOG.md](./CHANGELOG.md)
+
+Any issues?
+-----------
+
+Please, report about issues
+[here](https://github.com/unclechu/node-deep-extend/issues).
+
+License
+-------
+
+[MIT](./LICENSE)
diff --git a/server/node_modules/deep-extend/index.js b/server/node_modules/deep-extend/index.js
new file mode 100644
index 0000000..762d81e
--- /dev/null
+++ b/server/node_modules/deep-extend/index.js
@@ -0,0 +1 @@
+module.exports = require('./lib/deep-extend');
diff --git a/server/node_modules/deep-extend/lib/deep-extend.js b/server/node_modules/deep-extend/lib/deep-extend.js
new file mode 100644
index 0000000..651fd8d
--- /dev/null
+++ b/server/node_modules/deep-extend/lib/deep-extend.js
@@ -0,0 +1,150 @@
+/*!
+ * @description Recursive object extending
+ * @author Viacheslav Lotsmanov <lotsmanov89@gmail.com>
+ * @license MIT
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013-2018 Viacheslav Lotsmanov
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+'use strict';
+
+function isSpecificValue(val) {
+	return (
+		val instanceof Buffer
+		|| val instanceof Date
+		|| val instanceof RegExp
+	) ? true : false;
+}
+
+function cloneSpecificValue(val) {
+	if (val instanceof Buffer) {
+		var x = Buffer.alloc
+			? Buffer.alloc(val.length)
+			: new Buffer(val.length);
+		val.copy(x);
+		return x;
+	} else if (val instanceof Date) {
+		return new Date(val.getTime());
+	} else if (val instanceof RegExp) {
+		return new RegExp(val);
+	} else {
+		throw new Error('Unexpected situation');
+	}
+}
+
+/**
+ * Recursive cloning array.
+ */
+function deepCloneArray(arr) {
+	var clone = [];
+	arr.forEach(function (item, index) {
+		if (typeof item === 'object' && item !== null) {
+			if (Array.isArray(item)) {
+				clone[index] = deepCloneArray(item);
+			} else if (isSpecificValue(item)) {
+				clone[index] = cloneSpecificValue(item);
+			} else {
+				clone[index] = deepExtend({}, item);
+			}
+		} else {
+			clone[index] = item;
+		}
+	});
+	return clone;
+}
+
+function safeGetProperty(object, property) {
+	return property === '__proto__' ? undefined : object[property];
+}
+
+/**
+ * Extening object that entered in first argument.
+ *
+ * Returns extended object or false if have no target object or incorrect type.
+ *
+ * If you wish to clone source object (without modify it), just use empty new
+ * object as first argument, like this:
+ *   deepExtend({}, yourObj_1, [yourObj_N]);
+ */
+var deepExtend = module.exports = function (/*obj_1, [obj_2], [obj_N]*/) {
+	if (arguments.length < 1 || typeof arguments[0] !== 'object') {
+		return false;
+	}
+
+	if (arguments.length < 2) {
+		return arguments[0];
+	}
+
+	var target = arguments[0];
+
+	// convert arguments to array and cut off target object
+	var args = Array.prototype.slice.call(arguments, 1);
+
+	var val, src, clone;
+
+	args.forEach(function (obj) {
+		// skip argument if isn't an object, is null, or is an array
+		if (typeof obj !== 'object' || obj === null || Array.isArray(obj)) {
+			return;
+		}
+
+		Object.keys(obj).forEach(function (key) {
+			src = safeGetProperty(target, key); // source value
+			val = safeGetProperty(obj, key); // new value
+
+			// recursion prevention
+			if (val === target) {
+				return;
+
+			/**
+			 * if new value isn't object then just overwrite by new value
+			 * instead of extending.
+			 */
+			} else if (typeof val !== 'object' || val === null) {
+				target[key] = val;
+				return;
+
+			// just clone arrays (and recursive clone objects inside)
+			} else if (Array.isArray(val)) {
+				target[key] = deepCloneArray(val);
+				return;
+
+			// custom cloning and overwrite for specific objects
+			} else if (isSpecificValue(val)) {
+				target[key] = cloneSpecificValue(val);
+				return;
+
+			// overwrite by new value if source isn't object or array
+			} else if (typeof src !== 'object' || src === null || Array.isArray(src)) {
+				target[key] = deepExtend({}, val);
+				return;
+
+			// source value and new value is objects both, extending...
+			} else {
+				target[key] = deepExtend(src, val);
+				return;
+			}
+		});
+	});
+
+	return target;
+};
diff --git a/server/node_modules/deep-extend/package.json b/server/node_modules/deep-extend/package.json
new file mode 100644
index 0000000..5f2195f
--- /dev/null
+++ b/server/node_modules/deep-extend/package.json
@@ -0,0 +1,62 @@
+{
+  "name": "deep-extend",
+  "description": "Recursive object extending",
+  "license": "MIT",
+  "version": "0.6.0",
+  "homepage": "https://github.com/unclechu/node-deep-extend",
+  "keywords": [
+    "deep-extend",
+    "extend",
+    "deep",
+    "recursive",
+    "xtend",
+    "clone",
+    "merge",
+    "json"
+  ],
+  "licenses": [
+    {
+      "type": "MIT",
+      "url": "https://raw.githubusercontent.com/unclechu/node-deep-extend/master/LICENSE"
+    }
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/unclechu/node-deep-extend.git"
+  },
+  "author": "Viacheslav Lotsmanov <lotsmanov89@gmail.com>",
+  "bugs": "https://github.com/unclechu/node-deep-extend/issues",
+  "contributors": [
+    {
+      "name": "Romain Prieto",
+      "url": "https://github.com/rprieto"
+    },
+    {
+      "name": "Max Maximov",
+      "url": "https://github.com/maxmaximov"
+    },
+    {
+      "name": "Marshall Bowers",
+      "url": "https://github.com/maxdeviant"
+    },
+    {
+      "name": "Misha Wakerman",
+      "url": "https://github.com/mwakerman"
+    }
+  ],
+  "main": "lib/deep-extend.js",
+  "engines": {
+    "node": ">=4.0.0"
+  },
+  "scripts": {
+    "test": "./node_modules/.bin/mocha"
+  },
+  "devDependencies": {
+    "mocha": "5.2.0",
+    "should": "13.2.1"
+  },
+  "files": [
+    "index.js",
+    "lib/"
+  ]
+}
diff --git a/server/node_modules/delegates/.npmignore b/server/node_modules/delegates/.npmignore
new file mode 100644
index 0000000..c2658d7
--- /dev/null
+++ b/server/node_modules/delegates/.npmignore
@@ -0,0 +1 @@
+node_modules/
diff --git a/server/node_modules/delegates/History.md b/server/node_modules/delegates/History.md
new file mode 100644
index 0000000..25959ea
--- /dev/null
+++ b/server/node_modules/delegates/History.md
@@ -0,0 +1,22 @@
+
+1.0.0 / 2015-12-14
+==================
+
+  * Merge pull request #12 from kasicka/master
+  * Add license text
+
+0.1.0 / 2014-10-17
+==================
+
+ * adds `.fluent()` to api
+
+0.0.3 / 2014-01-13
+==================
+
+ * fix receiver for .method()
+
+0.0.2 / 2014-01-13
+==================
+
+ * Object.defineProperty() sucks
+ * Initial commit
diff --git a/server/node_modules/delegates/License b/server/node_modules/delegates/License
new file mode 100644
index 0000000..60de60a
--- /dev/null
+++ b/server/node_modules/delegates/License
@@ -0,0 +1,20 @@
+Copyright (c) 2015 TJ Holowaychuk <tj@vision-media.ca>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/delegates/Makefile b/server/node_modules/delegates/Makefile
new file mode 100644
index 0000000..a9dcfd5
--- /dev/null
+++ b/server/node_modules/delegates/Makefile
@@ -0,0 +1,8 @@
+
+test:
+	@./node_modules/.bin/mocha \
+		--require should \
+		--reporter spec \
+		--bail
+
+.PHONY: test
\ No newline at end of file
diff --git a/server/node_modules/delegates/Readme.md b/server/node_modules/delegates/Readme.md
new file mode 100644
index 0000000..ab8cf4a
--- /dev/null
+++ b/server/node_modules/delegates/Readme.md
@@ -0,0 +1,94 @@
+
+# delegates
+
+  Node method and accessor delegation utilty.
+
+## Installation
+
+```
+$ npm install delegates
+```
+
+## Example
+
+```js
+var delegate = require('delegates');
+
+...
+
+delegate(proto, 'request')
+  .method('acceptsLanguages')
+  .method('acceptsEncodings')
+  .method('acceptsCharsets')
+  .method('accepts')
+  .method('is')
+  .access('querystring')
+  .access('idempotent')
+  .access('socket')
+  .access('length')
+  .access('query')
+  .access('search')
+  .access('status')
+  .access('method')
+  .access('path')
+  .access('body')
+  .access('host')
+  .access('url')
+  .getter('subdomains')
+  .getter('protocol')
+  .getter('header')
+  .getter('stale')
+  .getter('fresh')
+  .getter('secure')
+  .getter('ips')
+  .getter('ip')
+```
+
+# API
+
+## Delegate(proto, prop)
+
+Creates a delegator instance used to configure using the `prop` on the given
+`proto` object. (which is usually a prototype)
+
+## Delegate#method(name)
+
+Allows the given method `name` to be accessed on the host.
+
+## Delegate#getter(name)
+
+Creates a "getter" for the property with the given `name` on the delegated
+object.
+
+## Delegate#setter(name)
+
+Creates a "setter" for the property with the given `name` on the delegated
+object.
+
+## Delegate#access(name)
+
+Creates an "accessor" (ie: both getter *and* setter) for the property with the
+given `name` on the delegated object.
+
+## Delegate#fluent(name)
+
+A unique type of "accessor" that works for a "fluent" API. When called as a
+getter, the method returns the expected value. However, if the method is called
+with a value, it will return itself so it can be chained. For example:
+
+```js
+delegate(proto, 'request')
+  .fluent('query')
+
+// getter
+var q = request.query();
+
+// setter (chainable)
+request
+  .query({ a: 1 })
+  .query({ b: 2 });
+```
+
+# License
+
+  MIT
diff --git a/server/node_modules/delegates/index.js b/server/node_modules/delegates/index.js
new file mode 100644
index 0000000..17c222d
--- /dev/null
+++ b/server/node_modules/delegates/index.js
@@ -0,0 +1,121 @@
+
+/**
+ * Expose `Delegator`.
+ */
+
+module.exports = Delegator;
+
+/**
+ * Initialize a delegator.
+ *
+ * @param {Object} proto
+ * @param {String} target
+ * @api public
+ */
+
+function Delegator(proto, target) {
+  if (!(this instanceof Delegator)) return new Delegator(proto, target);
+  this.proto = proto;
+  this.target = target;
+  this.methods = [];
+  this.getters = [];
+  this.setters = [];
+  this.fluents = [];
+}
+
+/**
+ * Delegate method `name`.
+ *
+ * @param {String} name
+ * @return {Delegator} self
+ * @api public
+ */
+
+Delegator.prototype.method = function(name){
+  var proto = this.proto;
+  var target = this.target;
+  this.methods.push(name);
+
+  proto[name] = function(){
+    return this[target][name].apply(this[target], arguments);
+  };
+
+  return this;
+};
+
+/**
+ * Delegator accessor `name`.
+ *
+ * @param {String} name
+ * @return {Delegator} self
+ * @api public
+ */
+
+Delegator.prototype.access = function(name){
+  return this.getter(name).setter(name);
+};
+
+/**
+ * Delegator getter `name`.
+ *
+ * @param {String} name
+ * @return {Delegator} self
+ * @api public
+ */
+
+Delegator.prototype.getter = function(name){
+  var proto = this.proto;
+  var target = this.target;
+  this.getters.push(name);
+
+  proto.__defineGetter__(name, function(){
+    return this[target][name];
+  });
+
+  return this;
+};
+
+/**
+ * Delegator setter `name`.
+ *
+ * @param {String} name
+ * @return {Delegator} self
+ * @api public
+ */
+
+Delegator.prototype.setter = function(name){
+  var proto = this.proto;
+  var target = this.target;
+  this.setters.push(name);
+
+  proto.__defineSetter__(name, function(val){
+    return this[target][name] = val;
+  });
+
+  return this;
+};
+
+/**
+ * Delegator fluent accessor
+ *
+ * @param {String} name
+ * @return {Delegator} self
+ * @api public
+ */
+
+Delegator.prototype.fluent = function (name) {
+  var proto = this.proto;
+  var target = this.target;
+  this.fluents.push(name);
+
+  proto[name] = function(val){
+    if ('undefined' != typeof val) {
+      this[target][name] = val;
+      return this;
+    } else {
+      return this[target][name];
+    }
+  };
+
+  return this;
+};
diff --git a/server/node_modules/delegates/package.json b/server/node_modules/delegates/package.json
new file mode 100644
index 0000000..1724038
--- /dev/null
+++ b/server/node_modules/delegates/package.json
@@ -0,0 +1,13 @@
+{
+  "name": "delegates",
+  "version": "1.0.0",
+  "repository": "visionmedia/node-delegates",
+  "description": "delegate methods and accessors to another property",
+  "keywords": ["delegate", "delegation"],
+  "dependencies": {},
+  "devDependencies": {
+    "mocha": "*",
+    "should": "*"
+  },
+  "license": "MIT"
+}
diff --git a/server/node_modules/delegates/test/index.js b/server/node_modules/delegates/test/index.js
new file mode 100644
index 0000000..7b6e3d4
--- /dev/null
+++ b/server/node_modules/delegates/test/index.js
@@ -0,0 +1,94 @@
+
+var assert = require('assert');
+var delegate = require('..');
+
+describe('.method(name)', function(){
+  it('should delegate methods', function(){
+    var obj = {};
+
+    obj.request = {
+      foo: function(bar){
+        assert(this == obj.request);
+        return bar;
+      }
+    };
+
+    delegate(obj, 'request').method('foo');
+
+    obj.foo('something').should.equal('something');
+  })
+})
+
+describe('.getter(name)', function(){
+  it('should delegate getters', function(){
+    var obj = {};
+
+    obj.request = {
+      get type() {
+        return 'text/html';
+      }
+    }
+
+    delegate(obj, 'request').getter('type');
+
+    obj.type.should.equal('text/html');
+  })
+})
+
+describe('.setter(name)', function(){
+  it('should delegate setters', function(){
+    var obj = {};
+
+    obj.request = {
+      get type() {
+        return this._type.toUpperCase();
+      },
+
+      set type(val) {
+        this._type = val;
+      }
+    }
+
+    delegate(obj, 'request').setter('type');
+
+    obj.type = 'hey';
+    obj.request.type.should.equal('HEY');
+  })
+})
+
+describe('.access(name)', function(){
+  it('should delegate getters and setters', function(){
+    var obj = {};
+
+    obj.request = {
+      get type() {
+        return this._type.toUpperCase();
+      },
+
+      set type(val) {
+        this._type = val;
+      }
+    }
+
+    delegate(obj, 'request').access('type');
+
+    obj.type = 'hey';
+    obj.type.should.equal('HEY');
+  })
+})
+
+describe('.fluent(name)', function () {
+  it('should delegate in a fluent fashion', function () {
+    var obj = {
+      settings: {
+        env: 'development'
+      }
+    };
+
+    delegate(obj, 'settings').fluent('env');
+
+    obj.env().should.equal('development');
+    obj.env('production').should.equal(obj);
+    obj.settings.env.should.equal('production');
+  })
+})
diff --git a/server/node_modules/depd/History.md b/server/node_modules/depd/History.md
new file mode 100644
index 0000000..cd9ebaa
--- /dev/null
+++ b/server/node_modules/depd/History.md
@@ -0,0 +1,103 @@
+2.0.0 / 2018-10-26
+==================
+
+  * Drop support for Node.js 0.6
+  * Replace internal `eval` usage with `Function` constructor
+  * Use instance methods on `process` to check for listeners
+
+1.1.2 / 2018-01-11
+==================
+
+  * perf: remove argument reassignment
+  * Support Node.js 0.6 to 9.x
+
+1.1.1 / 2017-07-27
+==================
+
+  * Remove unnecessary `Buffer` loading
+  * Support Node.js 0.6 to 8.x
+
+1.1.0 / 2015-09-14
+==================
+
+  * Enable strict mode in more places
+  * Support io.js 3.x
+  * Support io.js 2.x
+  * Support web browser loading
+    - Requires bundler like Browserify or webpack
+
+1.0.1 / 2015-04-07
+==================
+
+  * Fix `TypeError`s when under `'use strict'` code
+  * Fix useless type name on auto-generated messages
+  * Support io.js 1.x
+  * Support Node.js 0.12
+
+1.0.0 / 2014-09-17
+==================
+
+  * No changes
+
+0.4.5 / 2014-09-09
+==================
+
+  * Improve call speed to functions using the function wrapper
+  * Support Node.js 0.6
+
+0.4.4 / 2014-07-27
+==================
+
+  * Work-around v8 generating empty stack traces
+
+0.4.3 / 2014-07-26
+==================
+
+  * Fix exception when global `Error.stackTraceLimit` is too low
+
+0.4.2 / 2014-07-19
+==================
+
+  * Correct call site for wrapped functions and properties
+
+0.4.1 / 2014-07-19
+==================
+
+  * Improve automatic message generation for function properties
+
+0.4.0 / 2014-07-19
+==================
+
+  * Add `TRACE_DEPRECATION` environment variable
+  * Remove non-standard grey color from color output
+  * Support `--no-deprecation` argument
+  * Support `--trace-deprecation` argument
+  * Support `deprecate.property(fn, prop, message)`
+
+0.3.0 / 2014-06-16
+==================
+
+  * Add `NO_DEPRECATION` environment variable
+
+0.2.0 / 2014-06-15
+==================
+
+  * Add `deprecate.property(obj, prop, message)`
+  * Remove `supports-color` dependency for node.js 0.8
+
+0.1.0 / 2014-06-15
+==================
+
+  * Add `deprecate.function(fn, message)`
+  * Add `process.on('deprecation', fn)` emitter
+  * Automatically generate message when omitted from `deprecate()`
+
+0.0.1 / 2014-06-15
+==================
+
+  * Fix warning for dynamic calls at singe call site
+
+0.0.0 / 2014-06-15
+==================
+
+  * Initial implementation
diff --git a/server/node_modules/depd/LICENSE b/server/node_modules/depd/LICENSE
new file mode 100644
index 0000000..248de7a
--- /dev/null
+++ b/server/node_modules/depd/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2014-2018 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/depd/Readme.md b/server/node_modules/depd/Readme.md
new file mode 100644
index 0000000..043d1ca
--- /dev/null
+++ b/server/node_modules/depd/Readme.md
@@ -0,0 +1,280 @@
+# depd
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-image]][node-url]
+[![Linux Build][travis-image]][travis-url]
+[![Windows Build][appveyor-image]][appveyor-url]
+[![Coverage Status][coveralls-image]][coveralls-url]
+
+Deprecate all the things
+
+> With great modules comes great responsibility; mark things deprecated!
+
+## Install
+
+This module is installed directly using `npm`:
+
+```sh
+$ npm install depd
+```
+
+This module can also be bundled with systems like
+[Browserify](http://browserify.org/) or [webpack](https://webpack.github.io/),
+though by default this module will alter it's API to no longer display or
+track deprecations.
+
+## API
+
+
+
+```js
+var deprecate = require('depd')('my-module')
+```
+
+This library allows you to display deprecation messages to your users.
+This library goes above and beyond with deprecation warnings by
+introspection of the call stack (but only the bits that it is interested
+in).
+
+Instead of just warning on the first invocation of a deprecated
+function and never again, this module will warn on the first invocation
+of a deprecated function per unique call site, making it ideal to alert
+users of all deprecated uses across the code base, rather than just
+whatever happens to execute first.
+
+The deprecation warnings from this module also include the file and line
+information for the call into the module that the deprecated function was
+in.
+
+**NOTE** this library has a similar interface to the `debug` module, and
+this module uses the calling file to get the boundary for the call stacks,
+so you should always create a new `deprecate` object in each file and not
+within some central file.
+
+### depd(namespace)
+
+Create a new deprecate function that uses the given namespace name in the
+messages and will display the call site prior to the stack entering the
+file this function was called from. It is highly suggested you use the
+name of your module as the namespace.
+
+### deprecate(message)
+
+Call this function from deprecated code to display a deprecation message.
+This message will appear once per unique caller site. Caller site is the
+first call site in the stack in a different file from the caller of this
+function.
+
+If the message is omitted, a message is generated for you based on the site
+of the `deprecate()` call and will display the name of the function called,
+similar to the name displayed in a stack trace.
+
+### deprecate.function(fn, message)
+
+Call this function to wrap a given function in a deprecation message on any
+call to the function. An optional message can be supplied to provide a custom
+message.
+
+### deprecate.property(obj, prop, message)
+
+Call this function to wrap a given property on object in a deprecation message
+on any accessing or setting of the property. An optional message can be supplied
+to provide a custom message.
+
+The method must be called on the object where the property belongs (not
+inherited from the prototype).
+
+If the property is a data descriptor, it will be converted to an accessor
+descriptor in order to display the deprecation message.
+
+### process.on('deprecation', fn)
+
+This module will allow easy capturing of deprecation errors by emitting the
+errors as the type "deprecation" on the global `process`. If there are no
+listeners for this type, the errors are written to STDERR as normal, but if
+there are any listeners, nothing will be written to STDERR and instead only
+emitted. From there, you can write the errors in a different format or to a
+logging source.
+
+The error represents the deprecation and is emitted only once with the same
+rules as writing to STDERR. The error has the following properties:
+
+  - `message` - This is the message given by the library
+  - `name` - This is always `'DeprecationError'`
+  - `namespace` - This is the namespace the deprecation came from
+  - `stack` - This is the stack of the call to the deprecated thing
+
+Example `error.stack` output:
+
+```
+DeprecationError: my-cool-module deprecated oldfunction
+    at Object.<anonymous> ([eval]-wrapper:6:22)
+    at Module._compile (module.js:456:26)
+    at evalScript (node.js:532:25)
+    at startup (node.js:80:7)
+    at node.js:902:3
+```
+
+### process.env.NO_DEPRECATION
+
+As a user of modules that are deprecated, the environment variable `NO_DEPRECATION`
+is provided as a quick solution to silencing deprecation warnings from being
+output. The format of this is similar to that of `DEBUG`:
+
+```sh
+$ NO_DEPRECATION=my-module,othermod node app.js
+```
+
+This will suppress deprecations from being output for "my-module" and "othermod".
+The value is a list of comma-separated namespaces. To suppress every warning
+across all namespaces, use the value `*` for a namespace.
+
+Providing the argument `--no-deprecation` to the `node` executable will suppress
+all deprecations (only available in Node.js 0.8 or higher).
+
+**NOTE** This will not suppress the deperecations given to any "deprecation"
+event listeners, just the output to STDERR.
+
+### process.env.TRACE_DEPRECATION
+
+As a user of modules that are deprecated, the environment variable `TRACE_DEPRECATION`
+is provided as a solution to getting more detailed location information in deprecation
+warnings by including the entire stack trace. The format of this is the same as
+`NO_DEPRECATION`:
+
+```sh
+$ TRACE_DEPRECATION=my-module,othermod node app.js
+```
+
+This will include stack traces for deprecations being output for "my-module" and
+"othermod". The value is a list of comma-separated namespaces. To trace every
+warning across all namespaces, use the value `*` for a namespace.
+
+Providing the argument `--trace-deprecation` to the `node` executable will trace
+all deprecations (only available in Node.js 0.8 or higher).
+
+**NOTE** This will not trace the deperecations silenced by `NO_DEPRECATION`.
+
+## Display
+
+![message](files/message.png)
+
+When a user calls a function in your library that you mark deprecated, they
+will see the following written to STDERR (in the given colors, similar colors
+and layout to the `debug` module):
+
+```
+bright cyan    bright yellow
+|              |          reset       cyan
+|              |          |           |
+▼              ▼          ▼           ▼
+my-cool-module deprecated oldfunction [eval]-wrapper:6:22
+▲              ▲          ▲           ▲
+|              |          |           |
+namespace      |          |           location of mycoolmod.oldfunction() call
+               |          deprecation message
+               the word "deprecated"
+```
+
+If the user redirects their STDERR to a file or somewhere that does not support
+colors, they see (similar layout to the `debug` module):
+
+```
+Sun, 15 Jun 2014 05:21:37 GMT my-cool-module deprecated oldfunction at [eval]-wrapper:6:22
+▲                             ▲              ▲          ▲              ▲
+|                             |              |          |              |
+timestamp of message          namespace      |          |             location of mycoolmod.oldfunction() call
+                                             |          deprecation message
+                                             the word "deprecated"
+```
+
+## Examples
+
+### Deprecating all calls to a function
+
+This will display a deprecated message about "oldfunction" being deprecated
+from "my-module" on STDERR.
+
+```js
+var deprecate = require('depd')('my-cool-module')
+
+// message automatically derived from function name
+// Object.oldfunction
+exports.oldfunction = deprecate.function(function oldfunction () {
+  // all calls to function are deprecated
+})
+
+// specific message
+exports.oldfunction = deprecate.function(function () {
+  // all calls to function are deprecated
+}, 'oldfunction')
+```
+
+### Conditionally deprecating a function call
+
+This will display a deprecated message about "weirdfunction" being deprecated
+from "my-module" on STDERR when called with less than 2 arguments.
+
+```js
+var deprecate = require('depd')('my-cool-module')
+
+exports.weirdfunction = function () {
+  if (arguments.length < 2) {
+    // calls with 0 or 1 args are deprecated
+    deprecate('weirdfunction args < 2')
+  }
+}
+```
+
+When calling `deprecate` as a function, the warning is counted per call site
+within your own module, so you can display different deprecations depending
+on different situations and the users will still get all the warnings:
+
+```js
+var deprecate = require('depd')('my-cool-module')
+
+exports.weirdfunction = function () {
+  if (arguments.length < 2) {
+    // calls with 0 or 1 args are deprecated
+    deprecate('weirdfunction args < 2')
+  } else if (typeof arguments[0] !== 'string') {
+    // calls with non-string first argument are deprecated
+    deprecate('weirdfunction non-string first arg')
+  }
+}
+```
+
+### Deprecating property access
+
+This will display a deprecated message about "oldprop" being deprecated
+from "my-module" on STDERR when accessed. A deprecation will be displayed
+when setting the value and when getting the value.
+
+```js
+var deprecate = require('depd')('my-cool-module')
+
+exports.oldprop = 'something'
+
+// message automatically derives from property name
+deprecate.property(exports, 'oldprop')
+
+// explicit message
+deprecate.property(exports, 'oldprop', 'oldprop >= 0.10')
+```
+
+## License
+
+[MIT](LICENSE)
+
+[appveyor-image]: https://badgen.net/appveyor/ci/dougwilson/nodejs-depd/master?label=windows
+[appveyor-url]: https://ci.appveyor.com/project/dougwilson/nodejs-depd
+[coveralls-image]: https://badgen.net/coveralls/c/github/dougwilson/nodejs-depd/master
+[coveralls-url]: https://coveralls.io/r/dougwilson/nodejs-depd?branch=master
+[node-image]: https://badgen.net/npm/node/depd
+[node-url]: https://nodejs.org/en/download/
+[npm-downloads-image]: https://badgen.net/npm/dm/depd
+[npm-url]: https://npmjs.org/package/depd
+[npm-version-image]: https://badgen.net/npm/v/depd
+[travis-image]: https://badgen.net/travis/dougwilson/nodejs-depd/master?label=linux
+[travis-url]: https://travis-ci.org/dougwilson/nodejs-depd
diff --git a/server/node_modules/depd/index.js b/server/node_modules/depd/index.js
new file mode 100644
index 0000000..1bf2fcf
--- /dev/null
+++ b/server/node_modules/depd/index.js
@@ -0,0 +1,538 @@
+/*!
+ * depd
+ * Copyright(c) 2014-2018 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+/**
+ * Module dependencies.
+ */
+
+var relative = require('path').relative
+
+/**
+ * Module exports.
+ */
+
+module.exports = depd
+
+/**
+ * Get the path to base files on.
+ */
+
+var basePath = process.cwd()
+
+/**
+ * Determine if namespace is contained in the string.
+ */
+
+function containsNamespace (str, namespace) {
+  var vals = str.split(/[ ,]+/)
+  var ns = String(namespace).toLowerCase()
+
+  for (var i = 0; i < vals.length; i++) {
+    var val = vals[i]
+
+    // namespace contained
+    if (val && (val === '*' || val.toLowerCase() === ns)) {
+      return true
+    }
+  }
+
+  return false
+}
+
+/**
+ * Convert a data descriptor to accessor descriptor.
+ */
+
+function convertDataDescriptorToAccessor (obj, prop, message) {
+  var descriptor = Object.getOwnPropertyDescriptor(obj, prop)
+  var value = descriptor.value
+
+  descriptor.get = function getter () { return value }
+
+  if (descriptor.writable) {
+    descriptor.set = function setter (val) { return (value = val) }
+  }
+
+  delete descriptor.value
+  delete descriptor.writable
+
+  Object.defineProperty(obj, prop, descriptor)
+
+  return descriptor
+}
+
+/**
+ * Create arguments string to keep arity.
+ */
+
+function createArgumentsString (arity) {
+  var str = ''
+
+  for (var i = 0; i < arity; i++) {
+    str += ', arg' + i
+  }
+
+  return str.substr(2)
+}
+
+/**
+ * Create stack string from stack.
+ */
+
+function createStackString (stack) {
+  var str = this.name + ': ' + this.namespace
+
+  if (this.message) {
+    str += ' deprecated ' + this.message
+  }
+
+  for (var i = 0; i < stack.length; i++) {
+    str += '\n    at ' + stack[i].toString()
+  }
+
+  return str
+}
+
+/**
+ * Create deprecate for namespace in caller.
+ */
+
+function depd (namespace) {
+  if (!namespace) {
+    throw new TypeError('argument namespace is required')
+  }
+
+  var stack = getStack()
+  var site = callSiteLocation(stack[1])
+  var file = site[0]
+
+  function deprecate (message) {
+    // call to self as log
+    log.call(deprecate, message)
+  }
+
+  deprecate._file = file
+  deprecate._ignored = isignored(namespace)
+  deprecate._namespace = namespace
+  deprecate._traced = istraced(namespace)
+  deprecate._warned = Object.create(null)
+
+  deprecate.function = wrapfunction
+  deprecate.property = wrapproperty
+
+  return deprecate
+}
+
+/**
+ * Determine if event emitter has listeners of a given type.
+ *
+ * The way to do this check is done three different ways in Node.js >= 0.8
+ * so this consolidates them into a minimal set using instance methods.
+ *
+ * @param {EventEmitter} emitter
+ * @param {string} type
+ * @returns {boolean}
+ * @private
+ */
+
+function eehaslisteners (emitter, type) {
+  var count = typeof emitter.listenerCount !== 'function'
+    ? emitter.listeners(type).length
+    : emitter.listenerCount(type)
+
+  return count > 0
+}
+
+/**
+ * Determine if namespace is ignored.
+ */
+
+function isignored (namespace) {
+  if (process.noDeprecation) {
+    // --no-deprecation support
+    return true
+  }
+
+  var str = process.env.NO_DEPRECATION || ''
+
+  // namespace ignored
+  return containsNamespace(str, namespace)
+}
+
+/**
+ * Determine if namespace is traced.
+ */
+
+function istraced (namespace) {
+  if (process.traceDeprecation) {
+    // --trace-deprecation support
+    return true
+  }
+
+  var str = process.env.TRACE_DEPRECATION || ''
+
+  // namespace traced
+  return containsNamespace(str, namespace)
+}
+
+/**
+ * Display deprecation message.
+ */
+
+function log (message, site) {
+  var haslisteners = eehaslisteners(process, 'deprecation')
+
+  // abort early if no destination
+  if (!haslisteners && this._ignored) {
+    return
+  }
+
+  var caller
+  var callFile
+  var callSite
+  var depSite
+  var i = 0
+  var seen = false
+  var stack = getStack()
+  var file = this._file
+
+  if (site) {
+    // provided site
+    depSite = site
+    callSite = callSiteLocation(stack[1])
+    callSite.name = depSite.name
+    file = callSite[0]
+  } else {
+    // get call site
+    i = 2
+    depSite = callSiteLocation(stack[i])
+    callSite = depSite
+  }
+
+  // get caller of deprecated thing in relation to file
+  for (; i < stack.length; i++) {
+    caller = callSiteLocation(stack[i])
+    callFile = caller[0]
+
+    if (callFile === file) {
+      seen = true
+    } else if (callFile === this._file) {
+      file = this._file
+    } else if (seen) {
+      break
+    }
+  }
+
+  var key = caller
+    ? depSite.join(':') + '__' + caller.join(':')
+    : undefined
+
+  if (key !== undefined && key in this._warned) {
+    // already warned
+    return
+  }
+
+  this._warned[key] = true
+
+  // generate automatic message from call site
+  var msg = message
+  if (!msg) {
+    msg = callSite === depSite || !callSite.name
+      ? defaultMessage(depSite)
+      : defaultMessage(callSite)
+  }
+
+  // emit deprecation if listeners exist
+  if (haslisteners) {
+    var err = DeprecationError(this._namespace, msg, stack.slice(i))
+    process.emit('deprecation', err)
+    return
+  }
+
+  // format and write message
+  var format = process.stderr.isTTY
+    ? formatColor
+    : formatPlain
+  var output = format.call(this, msg, caller, stack.slice(i))
+  process.stderr.write(output + '\n', 'utf8')
+}
+
+/**
+ * Get call site location as array.
+ */
+
+function callSiteLocation (callSite) {
+  var file = callSite.getFileName() || '<anonymous>'
+  var line = callSite.getLineNumber()
+  var colm = callSite.getColumnNumber()
+
+  if (callSite.isEval()) {
+    file = callSite.getEvalOrigin() + ', ' + file
+  }
+
+  var site = [file, line, colm]
+
+  site.callSite = callSite
+  site.name = callSite.getFunctionName()
+
+  return site
+}
+
+/**
+ * Generate a default message from the site.
+ */
+
+function defaultMessage (site) {
+  var callSite = site.callSite
+  var funcName = site.name
+
+  // make useful anonymous name
+  if (!funcName) {
+    funcName = '<anonymous@' + formatLocation(site) + '>'
+  }
+
+  var context = callSite.getThis()
+  var typeName = context && callSite.getTypeName()
+
+  // ignore useless type name
+  if (typeName === 'Object') {
+    typeName = undefined
+  }
+
+  // make useful type name
+  if (typeName === 'Function') {
+    typeName = context.name || typeName
+  }
+
+  return typeName && callSite.getMethodName()
+    ? typeName + '.' + funcName
+    : funcName
+}
+
+/**
+ * Format deprecation message without color.
+ */
+
+function formatPlain (msg, caller, stack) {
+  var timestamp = new Date().toUTCString()
+
+  var formatted = timestamp +
+    ' ' + this._namespace +
+    ' deprecated ' + msg
+
+  // add stack trace
+  if (this._traced) {
+    for (var i = 0; i < stack.length; i++) {
+      formatted += '\n    at ' + stack[i].toString()
+    }
+
+    return formatted
+  }
+
+  if (caller) {
+    formatted += ' at ' + formatLocation(caller)
+  }
+
+  return formatted
+}
+
+/**
+ * Format deprecation message with color.
+ */
+
+function formatColor (msg, caller, stack) {
+  var formatted = '\x1b[36;1m' + this._namespace + '\x1b[22;39m' + // bold cyan
+    ' \x1b[33;1mdeprecated\x1b[22;39m' + // bold yellow
+    ' \x1b[0m' + msg + '\x1b[39m' // reset
+
+  // add stack trace
+  if (this._traced) {
+    for (var i = 0; i < stack.length; i++) {
+      formatted += '\n    \x1b[36mat ' + stack[i].toString() + '\x1b[39m' // cyan
+    }
+
+    return formatted
+  }
+
+  if (caller) {
+    formatted += ' \x1b[36m' + formatLocation(caller) + '\x1b[39m' // cyan
+  }
+
+  return formatted
+}
+
+/**
+ * Format call site location.
+ */
+
+function formatLocation (callSite) {
+  return relative(basePath, callSite[0]) +
+    ':' + callSite[1] +
+    ':' + callSite[2]
+}
+
+/**
+ * Get the stack as array of call sites.
+ */
+
+function getStack () {
+  var limit = Error.stackTraceLimit
+  var obj = {}
+  var prep = Error.prepareStackTrace
+
+  Error.prepareStackTrace = prepareObjectStackTrace
+  Error.stackTraceLimit = Math.max(10, limit)
+
+  // capture the stack
+  Error.captureStackTrace(obj)
+
+  // slice this function off the top
+  var stack = obj.stack.slice(1)
+
+  Error.prepareStackTrace = prep
+  Error.stackTraceLimit = limit
+
+  return stack
+}
+
+/**
+ * Capture call site stack from v8.
+ */
+
+function prepareObjectStackTrace (obj, stack) {
+  return stack
+}
+
+/**
+ * Return a wrapped function in a deprecation message.
+ */
+
+function wrapfunction (fn, message) {
+  if (typeof fn !== 'function') {
+    throw new TypeError('argument fn must be a function')
+  }
+
+  var args = createArgumentsString(fn.length)
+  var stack = getStack()
+  var site = callSiteLocation(stack[1])
+
+  site.name = fn.name
+
+  // eslint-disable-next-line no-new-func
+  var deprecatedfn = new Function('fn', 'log', 'deprecate', 'message', 'site',
+    '"use strict"\n' +
+    'return function (' + args + ') {' +
+    'log.call(deprecate, message, site)\n' +
+    'return fn.apply(this, arguments)\n' +
+    '}')(fn, log, this, message, site)
+
+  return deprecatedfn
+}
+
+/**
+ * Wrap property in a deprecation message.
+ */
+
+function wrapproperty (obj, prop, message) {
+  if (!obj || (typeof obj !== 'object' && typeof obj !== 'function')) {
+    throw new TypeError('argument obj must be object')
+  }
+
+  var descriptor = Object.getOwnPropertyDescriptor(obj, prop)
+
+  if (!descriptor) {
+    throw new TypeError('must call property on owner object')
+  }
+
+  if (!descriptor.configurable) {
+    throw new TypeError('property must be configurable')
+  }
+
+  var deprecate = this
+  var stack = getStack()
+  var site = callSiteLocation(stack[1])
+
+  // set site name
+  site.name = prop
+
+  // convert data descriptor
+  if ('value' in descriptor) {
+    descriptor = convertDataDescriptorToAccessor(obj, prop, message)
+  }
+
+  var get = descriptor.get
+  var set = descriptor.set
+
+  // wrap getter
+  if (typeof get === 'function') {
+    descriptor.get = function getter () {
+      log.call(deprecate, message, site)
+      return get.apply(this, arguments)
+    }
+  }
+
+  // wrap setter
+  if (typeof set === 'function') {
+    descriptor.set = function setter () {
+      log.call(deprecate, message, site)
+      return set.apply(this, arguments)
+    }
+  }
+
+  Object.defineProperty(obj, prop, descriptor)
+}
+
+/**
+ * Create DeprecationError for deprecation
+ */
+
+function DeprecationError (namespace, message, stack) {
+  var error = new Error()
+  var stackString
+
+  Object.defineProperty(error, 'constructor', {
+    value: DeprecationError
+  })
+
+  Object.defineProperty(error, 'message', {
+    configurable: true,
+    enumerable: false,
+    value: message,
+    writable: true
+  })
+
+  Object.defineProperty(error, 'name', {
+    enumerable: false,
+    configurable: true,
+    value: 'DeprecationError',
+    writable: true
+  })
+
+  Object.defineProperty(error, 'namespace', {
+    configurable: true,
+    enumerable: false,
+    value: namespace,
+    writable: true
+  })
+
+  Object.defineProperty(error, 'stack', {
+    configurable: true,
+    enumerable: false,
+    get: function () {
+      if (stackString !== undefined) {
+        return stackString
+      }
+
+      // prepare stack trace
+      return (stackString = createStackString.call(this, stack))
+    },
+    set: function setter (val) {
+      stackString = val
+    }
+  })
+
+  return error
+}
diff --git a/server/node_modules/depd/lib/browser/index.js b/server/node_modules/depd/lib/browser/index.js
new file mode 100644
index 0000000..6be45cc
--- /dev/null
+++ b/server/node_modules/depd/lib/browser/index.js
@@ -0,0 +1,77 @@
+/*!
+ * depd
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = depd
+
+/**
+ * Create deprecate for namespace in caller.
+ */
+
+function depd (namespace) {
+  if (!namespace) {
+    throw new TypeError('argument namespace is required')
+  }
+
+  function deprecate (message) {
+    // no-op in browser
+  }
+
+  deprecate._file = undefined
+  deprecate._ignored = true
+  deprecate._namespace = namespace
+  deprecate._traced = false
+  deprecate._warned = Object.create(null)
+
+  deprecate.function = wrapfunction
+  deprecate.property = wrapproperty
+
+  return deprecate
+}
+
+/**
+ * Return a wrapped function in a deprecation message.
+ *
+ * This is a no-op version of the wrapper, which does nothing but call
+ * validation.
+ */
+
+function wrapfunction (fn, message) {
+  if (typeof fn !== 'function') {
+    throw new TypeError('argument fn must be a function')
+  }
+
+  return fn
+}
+
+/**
+ * Wrap property in a deprecation message.
+ *
+ * This is a no-op version of the wrapper, which does nothing but call
+ * validation.
+ */
+
+function wrapproperty (obj, prop, message) {
+  if (!obj || (typeof obj !== 'object' && typeof obj !== 'function')) {
+    throw new TypeError('argument obj must be object')
+  }
+
+  var descriptor = Object.getOwnPropertyDescriptor(obj, prop)
+
+  if (!descriptor) {
+    throw new TypeError('must call property on owner object')
+  }
+
+  if (!descriptor.configurable) {
+    throw new TypeError('property must be configurable')
+  }
+}
diff --git a/server/node_modules/depd/package.json b/server/node_modules/depd/package.json
new file mode 100644
index 0000000..3857e19
--- /dev/null
+++ b/server/node_modules/depd/package.json
@@ -0,0 +1,45 @@
+{
+  "name": "depd",
+  "description": "Deprecate all the things",
+  "version": "2.0.0",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "keywords": [
+    "deprecate",
+    "deprecated"
+  ],
+  "repository": "dougwilson/nodejs-depd",
+  "browser": "lib/browser/index.js",
+  "devDependencies": {
+    "benchmark": "2.1.4",
+    "beautify-benchmark": "0.2.4",
+    "eslint": "5.7.0",
+    "eslint-config-standard": "12.0.0",
+    "eslint-plugin-import": "2.14.0",
+    "eslint-plugin-markdown": "1.0.0-beta.7",
+    "eslint-plugin-node": "7.0.1",
+    "eslint-plugin-promise": "4.0.1",
+    "eslint-plugin-standard": "4.0.0",
+    "istanbul": "0.4.5",
+    "mocha": "5.2.0",
+    "safe-buffer": "5.1.2",
+    "uid-safe": "2.1.5"
+  },
+  "files": [
+    "lib/",
+    "History.md",
+    "LICENSE",
+    "index.js",
+    "Readme.md"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec --bail test/",
+    "test-ci": "istanbul cover --print=none node_modules/mocha/bin/_mocha -- --reporter spec test/ && istanbul report lcovonly text-summary",
+    "test-cov": "istanbul cover --print=none node_modules/mocha/bin/_mocha -- --reporter dot test/ && istanbul report lcov text-summary"
+  }
+}
diff --git a/server/node_modules/destroy/LICENSE b/server/node_modules/destroy/LICENSE
new file mode 100644
index 0000000..0e2c35f
--- /dev/null
+++ b/server/node_modules/destroy/LICENSE
@@ -0,0 +1,23 @@
+
+The MIT License (MIT)
+
+Copyright (c) 2014 Jonathan Ong me@jongleberry.com
+Copyright (c) 2015-2022 Douglas Christopher Wilson doug@somethingdoug.com
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/destroy/README.md b/server/node_modules/destroy/README.md
new file mode 100644
index 0000000..e7701ae
--- /dev/null
+++ b/server/node_modules/destroy/README.md
@@ -0,0 +1,63 @@
+# destroy
+
+[![NPM version][npm-image]][npm-url]
+[![Build Status][github-actions-ci-image]][github-actions-ci-url]
+[![Test coverage][coveralls-image]][coveralls-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+Destroy a stream.
+
+This module is meant to ensure a stream gets destroyed, handling different APIs
+and Node.js bugs.
+
+## API
+
+```js
+var destroy = require('destroy')
+```
+
+### destroy(stream [, suppress])
+
+Destroy the given stream, and optionally suppress any future `error` events.
+
+In most cases, this is identical to a simple `stream.destroy()` call. The rules
+are as follows for a given stream:
+
+  1. If the `stream` is an instance of `ReadStream`, then call `stream.destroy()`
+     and add a listener to the `open` event to call `stream.close()` if it is
+     fired. This is for a Node.js bug that will leak a file descriptor if
+     `.destroy()` is called before `open`.
+  2. If the `stream` is an instance of a zlib stream, then call `stream.destroy()`
+     and close the underlying zlib handle if open, otherwise call `stream.close()`.
+     This is for consistency across Node.js versions and a Node.js bug that will
+     leak a native zlib handle.
+  3. If the `stream` is not an instance of `Stream`, then nothing happens.
+  4. If the `stream` has a `.destroy()` method, then call it.
+
+The function returns the `stream` passed in as the argument.
+
+## Example
+
+```js
+var destroy = require('destroy')
+
+var fs = require('fs')
+var stream = fs.createReadStream('package.json')
+
+// ... and later
+destroy(stream)
+```
+
+[npm-image]: https://img.shields.io/npm/v/destroy.svg?style=flat-square
+[npm-url]: https://npmjs.org/package/destroy
+[github-tag]: http://img.shields.io/github/tag/stream-utils/destroy.svg?style=flat-square
+[github-url]: https://github.com/stream-utils/destroy/tags
+[coveralls-image]: https://img.shields.io/coveralls/stream-utils/destroy.svg?style=flat-square
+[coveralls-url]: https://coveralls.io/r/stream-utils/destroy?branch=master
+[license-image]: http://img.shields.io/npm/l/destroy.svg?style=flat-square
+[license-url]: LICENSE.md
+[downloads-image]: http://img.shields.io/npm/dm/destroy.svg?style=flat-square
+[downloads-url]: https://npmjs.org/package/destroy
+[github-actions-ci-image]: https://img.shields.io/github/workflow/status/stream-utils/destroy/ci/master?label=ci&style=flat-square
+[github-actions-ci-url]: https://github.com/stream-utils/destroy/actions/workflows/ci.yml
diff --git a/server/node_modules/destroy/index.js b/server/node_modules/destroy/index.js
new file mode 100644
index 0000000..7fd5c09
--- /dev/null
+++ b/server/node_modules/destroy/index.js
@@ -0,0 +1,209 @@
+/*!
+ * destroy
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2015-2022 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var EventEmitter = require('events').EventEmitter
+var ReadStream = require('fs').ReadStream
+var Stream = require('stream')
+var Zlib = require('zlib')
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = destroy
+
+/**
+ * Destroy the given stream, and optionally suppress any future `error` events.
+ *
+ * @param {object} stream
+ * @param {boolean} suppress
+ * @public
+ */
+
+function destroy (stream, suppress) {
+  if (isFsReadStream(stream)) {
+    destroyReadStream(stream)
+  } else if (isZlibStream(stream)) {
+    destroyZlibStream(stream)
+  } else if (hasDestroy(stream)) {
+    stream.destroy()
+  }
+
+  if (isEventEmitter(stream) && suppress) {
+    stream.removeAllListeners('error')
+    stream.addListener('error', noop)
+  }
+
+  return stream
+}
+
+/**
+ * Destroy a ReadStream.
+ *
+ * @param {object} stream
+ * @private
+ */
+
+function destroyReadStream (stream) {
+  stream.destroy()
+
+  if (typeof stream.close === 'function') {
+    // node.js core bug work-around
+    stream.on('open', onOpenClose)
+  }
+}
+
+/**
+ * Close a Zlib stream.
+ *
+ * Zlib streams below Node.js 4.5.5 have a buggy implementation
+ * of .close() when zlib encountered an error.
+ *
+ * @param {object} stream
+ * @private
+ */
+
+function closeZlibStream (stream) {
+  if (stream._hadError === true) {
+    var prop = stream._binding === null
+      ? '_binding'
+      : '_handle'
+
+    stream[prop] = {
+      close: function () { this[prop] = null }
+    }
+  }
+
+  stream.close()
+}
+
+/**
+ * Destroy a Zlib stream.
+ *
+ * Zlib streams don't have a destroy function in Node.js 6. On top of that
+ * simply calling destroy on a zlib stream in Node.js 8+ will result in a
+ * memory leak. So until that is fixed, we need to call both close AND destroy.
+ *
+ * PR to fix memory leak: https://github.com/nodejs/node/pull/23734
+ *
+ * In Node.js 6+8, it's important that destroy is called before close as the
+ * stream would otherwise emit the error 'zlib binding closed'.
+ *
+ * @param {object} stream
+ * @private
+ */
+
+function destroyZlibStream (stream) {
+  if (typeof stream.destroy === 'function') {
+    // node.js core bug work-around
+    // istanbul ignore if: node.js 0.8
+    if (stream._binding) {
+      // node.js < 0.10.0
+      stream.destroy()
+      if (stream._processing) {
+        stream._needDrain = true
+        stream.once('drain', onDrainClearBinding)
+      } else {
+        stream._binding.clear()
+      }
+    } else if (stream._destroy && stream._destroy !== Stream.Transform.prototype._destroy) {
+      // node.js >= 12, ^11.1.0, ^10.15.1
+      stream.destroy()
+    } else if (stream._destroy && typeof stream.close === 'function') {
+      // node.js 7, 8
+      stream.destroyed = true
+      stream.close()
+    } else {
+      // fallback
+      // istanbul ignore next
+      stream.destroy()
+    }
+  } else if (typeof stream.close === 'function') {
+    // node.js < 8 fallback
+    closeZlibStream(stream)
+  }
+}
+
+/**
+ * Determine if stream has destroy.
+ * @private
+ */
+
+function hasDestroy (stream) {
+  return stream instanceof Stream &&
+    typeof stream.destroy === 'function'
+}
+
+/**
+ * Determine if val is EventEmitter.
+ * @private
+ */
+
+function isEventEmitter (val) {
+  return val instanceof EventEmitter
+}
+
+/**
+ * Determine if stream is fs.ReadStream stream.
+ * @private
+ */
+
+function isFsReadStream (stream) {
+  return stream instanceof ReadStream
+}
+
+/**
+ * Determine if stream is Zlib stream.
+ * @private
+ */
+
+function isZlibStream (stream) {
+  return stream instanceof Zlib.Gzip ||
+    stream instanceof Zlib.Gunzip ||
+    stream instanceof Zlib.Deflate ||
+    stream instanceof Zlib.DeflateRaw ||
+    stream instanceof Zlib.Inflate ||
+    stream instanceof Zlib.InflateRaw ||
+    stream instanceof Zlib.Unzip
+}
+
+/**
+ * No-op function.
+ * @private
+ */
+
+function noop () {}
+
+/**
+ * On drain handler to clear binding.
+ * @private
+ */
+
+// istanbul ignore next: node.js 0.8
+function onDrainClearBinding () {
+  this._binding.clear()
+}
+
+/**
+ * On open handler to close stream.
+ * @private
+ */
+
+function onOpenClose () {
+  if (typeof this.fd === 'number') {
+    // actually close down the fd
+    this.close()
+  }
+}
diff --git a/server/node_modules/destroy/package.json b/server/node_modules/destroy/package.json
new file mode 100644
index 0000000..c85e438
--- /dev/null
+++ b/server/node_modules/destroy/package.json
@@ -0,0 +1,48 @@
+{
+  "name": "destroy",
+  "description": "destroy a stream if possible",
+  "version": "1.2.0",
+  "author": {
+    "name": "Jonathan Ong",
+    "email": "me@jongleberry.com",
+    "url": "http://jongleberry.com",
+    "twitter": "https://twitter.com/jongleberry"
+  },
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>"
+  ],
+  "license": "MIT",
+  "repository": "stream-utils/destroy",
+  "devDependencies": {
+    "eslint": "7.32.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.25.4",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "5.2.0",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "9.2.2",
+    "nyc": "15.1.0"
+  },
+  "engines": {
+    "node": ">= 0.8",
+    "npm": "1.2.8000 || >= 1.4.16"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec",
+    "test-ci": "nyc --reporter=lcovonly --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  },
+  "files": [
+    "index.js",
+    "LICENSE"
+  ],
+  "keywords": [
+    "stream",
+    "streams",
+    "destroy",
+    "cleanup",
+    "leak",
+    "fd"
+  ]
+}
diff --git a/server/node_modules/detect-libc/LICENSE b/server/node_modules/detect-libc/LICENSE
new file mode 100644
index 0000000..8dada3e
--- /dev/null
+++ b/server/node_modules/detect-libc/LICENSE
@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
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+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
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+       http://www.apache.org/licenses/LICENSE-2.0
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diff --git a/server/node_modules/detect-libc/README.md b/server/node_modules/detect-libc/README.md
new file mode 100644
index 0000000..23212fd
--- /dev/null
+++ b/server/node_modules/detect-libc/README.md
@@ -0,0 +1,163 @@
+# detect-libc
+
+Node.js module to detect details of the C standard library (libc)
+implementation provided by a given Linux system.
+
+Currently supports detection of GNU glibc and MUSL libc.
+
+Provides asychronous and synchronous functions for the
+family (e.g. `glibc`, `musl`) and version (e.g. `1.23`, `1.2.3`).
+
+The version numbers of libc implementations
+are not guaranteed to be semver-compliant.
+
+For previous v1.x releases, please see the
+[v1](https://github.com/lovell/detect-libc/tree/v1) branch.
+
+## Install
+
+```sh
+npm install detect-libc
+```
+
+## API
+
+### GLIBC
+
+```ts
+const GLIBC: string = 'glibc';
+```
+
+A String constant containing the value `glibc`.
+
+### MUSL
+
+```ts
+const MUSL: string = 'musl';
+```
+
+A String constant containing the value `musl`.
+
+### family
+
+```ts
+function family(): Promise<string | null>;
+```
+
+Resolves asychronously with:
+
+* `glibc` or `musl` when the libc family can be determined
+* `null` when the libc family cannot be determined
+* `null` when run on a non-Linux platform
+
+```js
+const { family, GLIBC, MUSL } = require('detect-libc');
+
+switch (await family()) {
+  case GLIBC: ...
+  case MUSL: ...
+  case null: ...
+}
+```
+
+### familySync
+
+```ts
+function familySync(): string | null;
+```
+
+Synchronous version of `family()`.
+
+```js
+const { familySync, GLIBC, MUSL } = require('detect-libc');
+
+switch (familySync()) {
+  case GLIBC: ...
+  case MUSL: ...
+  case null: ...
+}
+```
+
+### version
+
+```ts
+function version(): Promise<string | null>;
+```
+
+Resolves asychronously with:
+
+* The version when it can be determined
+* `null` when the libc family cannot be determined
+* `null` when run on a non-Linux platform
+
+```js
+const { version } = require('detect-libc');
+
+const v = await version();
+if (v) {
+  const [major, minor, patch] = v.split('.');
+}
+```
+
+### versionSync
+
+```ts
+function versionSync(): string | null;
+```
+
+Synchronous version of `version()`.
+
+```js
+const { versionSync } = require('detect-libc');
+
+const v = versionSync();
+if (v) {
+  const [major, minor, patch] = v.split('.');
+}
+```
+
+### isNonGlibcLinux
+
+```ts
+function isNonGlibcLinux(): Promise<boolean>;
+```
+
+Resolves asychronously with:
+
+* `false` when the libc family is `glibc`
+* `true` when the libc family is not `glibc`
+* `false` when run on a non-Linux platform
+
+```js
+const { isNonGlibcLinux } = require('detect-libc');
+
+if (await isNonGlibcLinux()) { ... }
+```
+
+### isNonGlibcLinuxSync
+
+```ts
+function isNonGlibcLinuxSync(): boolean;
+```
+
+Synchronous version of `isNonGlibcLinux()`.
+
+```js
+const { isNonGlibcLinuxSync } = require('detect-libc');
+
+if (isNonGlibcLinuxSync()) { ... }
+```
+
+## Licensing
+
+Copyright 2017 Lovell Fuller and others.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at [http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0.html)
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
diff --git a/server/node_modules/detect-libc/index.d.ts b/server/node_modules/detect-libc/index.d.ts
new file mode 100644
index 0000000..4c0fb2b
--- /dev/null
+++ b/server/node_modules/detect-libc/index.d.ts
@@ -0,0 +1,14 @@
+// Copyright 2017 Lovell Fuller and others.
+// SPDX-License-Identifier: Apache-2.0
+
+export const GLIBC: 'glibc';
+export const MUSL: 'musl';
+
+export function family(): Promise<string | null>;
+export function familySync(): string | null;
+
+export function isNonGlibcLinux(): Promise<boolean>;
+export function isNonGlibcLinuxSync(): boolean;
+
+export function version(): Promise<string | null>;
+export function versionSync(): string | null;
diff --git a/server/node_modules/detect-libc/lib/detect-libc.js b/server/node_modules/detect-libc/lib/detect-libc.js
new file mode 100644
index 0000000..01299b4
--- /dev/null
+++ b/server/node_modules/detect-libc/lib/detect-libc.js
@@ -0,0 +1,313 @@
+// Copyright 2017 Lovell Fuller and others.
+// SPDX-License-Identifier: Apache-2.0
+
+'use strict';
+
+const childProcess = require('child_process');
+const { isLinux, getReport } = require('./process');
+const { LDD_PATH, SELF_PATH, readFile, readFileSync } = require('./filesystem');
+const { interpreterPath } = require('./elf');
+
+let cachedFamilyInterpreter;
+let cachedFamilyFilesystem;
+let cachedVersionFilesystem;
+
+const command = 'getconf GNU_LIBC_VERSION 2>&1 || true; ldd --version 2>&1 || true';
+let commandOut = '';
+
+const safeCommand = () => {
+  if (!commandOut) {
+    return new Promise((resolve) => {
+      childProcess.exec(command, (err, out) => {
+        commandOut = err ? ' ' : out;
+        resolve(commandOut);
+      });
+    });
+  }
+  return commandOut;
+};
+
+const safeCommandSync = () => {
+  if (!commandOut) {
+    try {
+      commandOut = childProcess.execSync(command, { encoding: 'utf8' });
+    } catch (_err) {
+      commandOut = ' ';
+    }
+  }
+  return commandOut;
+};
+
+/**
+ * A String constant containing the value `glibc`.
+ * @type {string}
+ * @public
+ */
+const GLIBC = 'glibc';
+
+/**
+ * A Regexp constant to get the GLIBC Version.
+ * @type {string}
+ */
+const RE_GLIBC_VERSION = /LIBC[a-z0-9 \-).]*?(\d+\.\d+)/i;
+
+/**
+ * A String constant containing the value `musl`.
+ * @type {string}
+ * @public
+ */
+const MUSL = 'musl';
+
+const isFileMusl = (f) => f.includes('libc.musl-') || f.includes('ld-musl-');
+
+const familyFromReport = () => {
+  const report = getReport();
+  if (report.header && report.header.glibcVersionRuntime) {
+    return GLIBC;
+  }
+  if (Array.isArray(report.sharedObjects)) {
+    if (report.sharedObjects.some(isFileMusl)) {
+      return MUSL;
+    }
+  }
+  return null;
+};
+
+const familyFromCommand = (out) => {
+  const [getconf, ldd1] = out.split(/[\r\n]+/);
+  if (getconf && getconf.includes(GLIBC)) {
+    return GLIBC;
+  }
+  if (ldd1 && ldd1.includes(MUSL)) {
+    return MUSL;
+  }
+  return null;
+};
+
+const familyFromInterpreterPath = (path) => {
+  if (path) {
+    if (path.includes('/ld-musl-')) {
+      return MUSL;
+    } else if (path.includes('/ld-linux-')) {
+      return GLIBC;
+    }
+  }
+  return null;
+};
+
+const getFamilyFromLddContent = (content) => {
+  content = content.toString();
+  if (content.includes('musl')) {
+    return MUSL;
+  }
+  if (content.includes('GNU C Library')) {
+    return GLIBC;
+  }
+  return null;
+};
+
+const familyFromFilesystem = async () => {
+  if (cachedFamilyFilesystem !== undefined) {
+    return cachedFamilyFilesystem;
+  }
+  cachedFamilyFilesystem = null;
+  try {
+    const lddContent = await readFile(LDD_PATH);
+    cachedFamilyFilesystem = getFamilyFromLddContent(lddContent);
+  } catch (e) {}
+  return cachedFamilyFilesystem;
+};
+
+const familyFromFilesystemSync = () => {
+  if (cachedFamilyFilesystem !== undefined) {
+    return cachedFamilyFilesystem;
+  }
+  cachedFamilyFilesystem = null;
+  try {
+    const lddContent = readFileSync(LDD_PATH);
+    cachedFamilyFilesystem = getFamilyFromLddContent(lddContent);
+  } catch (e) {}
+  return cachedFamilyFilesystem;
+};
+
+const familyFromInterpreter = async () => {
+  if (cachedFamilyInterpreter !== undefined) {
+    return cachedFamilyInterpreter;
+  }
+  cachedFamilyInterpreter = null;
+  try {
+    const selfContent = await readFile(SELF_PATH);
+    const path = interpreterPath(selfContent);
+    cachedFamilyInterpreter = familyFromInterpreterPath(path);
+  } catch (e) {}
+  return cachedFamilyInterpreter;
+};
+
+const familyFromInterpreterSync = () => {
+  if (cachedFamilyInterpreter !== undefined) {
+    return cachedFamilyInterpreter;
+  }
+  cachedFamilyInterpreter = null;
+  try {
+    const selfContent = readFileSync(SELF_PATH);
+    const path = interpreterPath(selfContent);
+    cachedFamilyInterpreter = familyFromInterpreterPath(path);
+  } catch (e) {}
+  return cachedFamilyInterpreter;
+};
+
+/**
+ * Resolves with the libc family when it can be determined, `null` otherwise.
+ * @returns {Promise<?string>}
+ */
+const family = async () => {
+  let family = null;
+  if (isLinux()) {
+    family = await familyFromInterpreter();
+    if (!family) {
+      family = await familyFromFilesystem();
+      if (!family) {
+        family = familyFromReport();
+      }
+      if (!family) {
+        const out = await safeCommand();
+        family = familyFromCommand(out);
+      }
+    }
+  }
+  return family;
+};
+
+/**
+ * Returns the libc family when it can be determined, `null` otherwise.
+ * @returns {?string}
+ */
+const familySync = () => {
+  let family = null;
+  if (isLinux()) {
+    family = familyFromInterpreterSync();
+    if (!family) {
+      family = familyFromFilesystemSync();
+      if (!family) {
+        family = familyFromReport();
+      }
+      if (!family) {
+        const out = safeCommandSync();
+        family = familyFromCommand(out);
+      }
+    }
+  }
+  return family;
+};
+
+/**
+ * Resolves `true` only when the platform is Linux and the libc family is not `glibc`.
+ * @returns {Promise<boolean>}
+ */
+const isNonGlibcLinux = async () => isLinux() && await family() !== GLIBC;
+
+/**
+ * Returns `true` only when the platform is Linux and the libc family is not `glibc`.
+ * @returns {boolean}
+ */
+const isNonGlibcLinuxSync = () => isLinux() && familySync() !== GLIBC;
+
+const versionFromFilesystem = async () => {
+  if (cachedVersionFilesystem !== undefined) {
+    return cachedVersionFilesystem;
+  }
+  cachedVersionFilesystem = null;
+  try {
+    const lddContent = await readFile(LDD_PATH);
+    const versionMatch = lddContent.match(RE_GLIBC_VERSION);
+    if (versionMatch) {
+      cachedVersionFilesystem = versionMatch[1];
+    }
+  } catch (e) {}
+  return cachedVersionFilesystem;
+};
+
+const versionFromFilesystemSync = () => {
+  if (cachedVersionFilesystem !== undefined) {
+    return cachedVersionFilesystem;
+  }
+  cachedVersionFilesystem = null;
+  try {
+    const lddContent = readFileSync(LDD_PATH);
+    const versionMatch = lddContent.match(RE_GLIBC_VERSION);
+    if (versionMatch) {
+      cachedVersionFilesystem = versionMatch[1];
+    }
+  } catch (e) {}
+  return cachedVersionFilesystem;
+};
+
+const versionFromReport = () => {
+  const report = getReport();
+  if (report.header && report.header.glibcVersionRuntime) {
+    return report.header.glibcVersionRuntime;
+  }
+  return null;
+};
+
+const versionSuffix = (s) => s.trim().split(/\s+/)[1];
+
+const versionFromCommand = (out) => {
+  const [getconf, ldd1, ldd2] = out.split(/[\r\n]+/);
+  if (getconf && getconf.includes(GLIBC)) {
+    return versionSuffix(getconf);
+  }
+  if (ldd1 && ldd2 && ldd1.includes(MUSL)) {
+    return versionSuffix(ldd2);
+  }
+  return null;
+};
+
+/**
+ * Resolves with the libc version when it can be determined, `null` otherwise.
+ * @returns {Promise<?string>}
+ */
+const version = async () => {
+  let version = null;
+  if (isLinux()) {
+    version = await versionFromFilesystem();
+    if (!version) {
+      version = versionFromReport();
+    }
+    if (!version) {
+      const out = await safeCommand();
+      version = versionFromCommand(out);
+    }
+  }
+  return version;
+};
+
+/**
+ * Returns the libc version when it can be determined, `null` otherwise.
+ * @returns {?string}
+ */
+const versionSync = () => {
+  let version = null;
+  if (isLinux()) {
+    version = versionFromFilesystemSync();
+    if (!version) {
+      version = versionFromReport();
+    }
+    if (!version) {
+      const out = safeCommandSync();
+      version = versionFromCommand(out);
+    }
+  }
+  return version;
+};
+
+module.exports = {
+  GLIBC,
+  MUSL,
+  family,
+  familySync,
+  isNonGlibcLinux,
+  isNonGlibcLinuxSync,
+  version,
+  versionSync
+};
diff --git a/server/node_modules/detect-libc/lib/elf.js b/server/node_modules/detect-libc/lib/elf.js
new file mode 100644
index 0000000..aa166aa
--- /dev/null
+++ b/server/node_modules/detect-libc/lib/elf.js
@@ -0,0 +1,39 @@
+// Copyright 2017 Lovell Fuller and others.
+// SPDX-License-Identifier: Apache-2.0
+
+'use strict';
+
+const interpreterPath = (elf) => {
+  if (elf.length < 64) {
+    return null;
+  }
+  if (elf.readUInt32BE(0) !== 0x7F454C46) {
+    // Unexpected magic bytes
+    return null;
+  }
+  if (elf.readUInt8(4) !== 2) {
+    // Not a 64-bit ELF
+    return null;
+  }
+  if (elf.readUInt8(5) !== 1) {
+    // Not little-endian
+    return null;
+  }
+  const offset = elf.readUInt32LE(32);
+  const size = elf.readUInt16LE(54);
+  const count = elf.readUInt16LE(56);
+  for (let i = 0; i < count; i++) {
+    const headerOffset = offset + (i * size);
+    const type = elf.readUInt32LE(headerOffset);
+    if (type === 3) {
+      const fileOffset = elf.readUInt32LE(headerOffset + 8);
+      const fileSize = elf.readUInt32LE(headerOffset + 32);
+      return elf.subarray(fileOffset, fileOffset + fileSize).toString().replace(/\0.*$/g, '');
+    }
+  }
+  return null;
+};
+
+module.exports = {
+  interpreterPath
+};
diff --git a/server/node_modules/detect-libc/lib/filesystem.js b/server/node_modules/detect-libc/lib/filesystem.js
new file mode 100644
index 0000000..4c2443c
--- /dev/null
+++ b/server/node_modules/detect-libc/lib/filesystem.js
@@ -0,0 +1,51 @@
+// Copyright 2017 Lovell Fuller and others.
+// SPDX-License-Identifier: Apache-2.0
+
+'use strict';
+
+const fs = require('fs');
+
+const LDD_PATH = '/usr/bin/ldd';
+const SELF_PATH = '/proc/self/exe';
+const MAX_LENGTH = 2048;
+
+/**
+ * Read the content of a file synchronous
+ *
+ * @param {string} path
+ * @returns {Buffer}
+ */
+const readFileSync = (path) => {
+  const fd = fs.openSync(path, 'r');
+  const buffer = Buffer.alloc(MAX_LENGTH);
+  const bytesRead = fs.readSync(fd, buffer, 0, MAX_LENGTH, 0);
+  fs.close(fd, () => {});
+  return buffer.subarray(0, bytesRead);
+};
+
+/**
+ * Read the content of a file
+ *
+ * @param {string} path
+ * @returns {Promise<Buffer>}
+ */
+const readFile = (path) => new Promise((resolve, reject) => {
+  fs.open(path, 'r', (err, fd) => {
+    if (err) {
+      reject(err);
+    } else {
+      const buffer = Buffer.alloc(MAX_LENGTH);
+      fs.read(fd, buffer, 0, MAX_LENGTH, 0, (_, bytesRead) => {
+        resolve(buffer.subarray(0, bytesRead));
+        fs.close(fd, () => {});
+      });
+    }
+  });
+});
+
+module.exports = {
+  LDD_PATH,
+  SELF_PATH,
+  readFileSync,
+  readFile
+};
diff --git a/server/node_modules/detect-libc/lib/process.js b/server/node_modules/detect-libc/lib/process.js
new file mode 100644
index 0000000..ee78ad2
--- /dev/null
+++ b/server/node_modules/detect-libc/lib/process.js
@@ -0,0 +1,24 @@
+// Copyright 2017 Lovell Fuller and others.
+// SPDX-License-Identifier: Apache-2.0
+
+'use strict';
+
+const isLinux = () => process.platform === 'linux';
+
+let report = null;
+const getReport = () => {
+  if (!report) {
+    /* istanbul ignore next */
+    if (isLinux() && process.report) {
+      const orig = process.report.excludeNetwork;
+      process.report.excludeNetwork = true;
+      report = process.report.getReport();
+      process.report.excludeNetwork = orig;
+    } else {
+      report = {};
+    }
+  }
+  return report;
+};
+
+module.exports = { isLinux, getReport };
diff --git a/server/node_modules/detect-libc/package.json b/server/node_modules/detect-libc/package.json
new file mode 100644
index 0000000..36d0f2b
--- /dev/null
+++ b/server/node_modules/detect-libc/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "detect-libc",
+  "version": "2.1.2",
+  "description": "Node.js module to detect the C standard library (libc) implementation family and version",
+  "main": "lib/detect-libc.js",
+  "files": [
+    "lib/",
+    "index.d.ts"
+  ],
+  "scripts": {
+    "test": "semistandard && nyc --reporter=text --check-coverage --branches=100 ava test/unit.js",
+    "changelog": "conventional-changelog -i CHANGELOG.md -s",
+    "bench": "node benchmark/detect-libc",
+    "bench:calls": "node benchmark/call-familySync.js && sleep 1 && node benchmark/call-isNonGlibcLinuxSync.js && sleep 1 && node benchmark/call-versionSync.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/lovell/detect-libc.git"
+  },
+  "keywords": [
+    "libc",
+    "glibc",
+    "musl"
+  ],
+  "author": "Lovell Fuller <npm@lovell.info>",
+  "contributors": [
+    "Niklas Salmoukas <niklas@salmoukas.com>",
+    "Vinícius Lourenço <vinyygamerlol@gmail.com>"
+  ],
+  "license": "Apache-2.0",
+  "devDependencies": {
+    "ava": "^2.4.0",
+    "benchmark": "^2.1.4",
+    "conventional-changelog-cli": "^5.0.0",
+    "eslint-config-standard": "^13.0.1",
+    "nyc": "^15.1.0",
+    "proxyquire": "^2.1.3",
+    "semistandard": "^14.2.3"
+  },
+  "engines": {
+    "node": ">=8"
+  },
+  "types": "index.d.ts"
+}
diff --git a/server/node_modules/dunder-proto/.eslintrc b/server/node_modules/dunder-proto/.eslintrc
new file mode 100644
index 0000000..3b5d9e9
--- /dev/null
+++ b/server/node_modules/dunder-proto/.eslintrc
@@ -0,0 +1,5 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+}
diff --git a/server/node_modules/dunder-proto/.github/FUNDING.yml b/server/node_modules/dunder-proto/.github/FUNDING.yml
new file mode 100644
index 0000000..8a1d7b0
--- /dev/null
+++ b/server/node_modules/dunder-proto/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/dunder-proto
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/dunder-proto/.nycrc b/server/node_modules/dunder-proto/.nycrc
new file mode 100644
index 0000000..1826526
--- /dev/null
+++ b/server/node_modules/dunder-proto/.nycrc
@@ -0,0 +1,13 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"lines": 86,
+	"statements": 85.93,
+	"functions": 82.43,
+	"branches": 76.06,
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/dunder-proto/CHANGELOG.md b/server/node_modules/dunder-proto/CHANGELOG.md
new file mode 100644
index 0000000..9b8b2f8
--- /dev/null
+++ b/server/node_modules/dunder-proto/CHANGELOG.md
@@ -0,0 +1,24 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.0.1](https://github.com/es-shims/dunder-proto/compare/v1.0.0...v1.0.1) - 2024-12-16
+
+### Commits
+
+- [Fix] do not crash when `--disable-proto=throw` [`6c367d9`](https://github.com/es-shims/dunder-proto/commit/6c367d919bc1604778689a297bbdbfea65752847)
+- [Tests] ensure noproto tests only use the current version of dunder-proto [`b02365b`](https://github.com/es-shims/dunder-proto/commit/b02365b9cf889c4a2cac7be0c3cfc90a789af36c)
+- [Dev Deps] update `@arethetypeswrong/cli`, `@types/tape` [`e3c5c3b`](https://github.com/es-shims/dunder-proto/commit/e3c5c3bd81cf8cef7dff2eca19e558f0e307f666)
+- [Deps] update `call-bind-apply-helpers` [`19f1da0`](https://github.com/es-shims/dunder-proto/commit/19f1da028b8dd0d05c85bfd8f7eed2819b686450)
+
+## v1.0.0 - 2024-12-06
+
+### Commits
+
+- Initial implementation, tests, readme, types [`a5b74b0`](https://github.com/es-shims/dunder-proto/commit/a5b74b0082f5270cb0905cd9a2e533cee7498373)
+- Initial commit [`73fb5a3`](https://github.com/es-shims/dunder-proto/commit/73fb5a353b51ac2ab00c9fdeb0114daffd4c07a8)
+- npm init [`80152dc`](https://github.com/es-shims/dunder-proto/commit/80152dc98155da4eb046d9f67a87ed96e8280a1d)
+- Only apps should have lockfiles [`03e6660`](https://github.com/es-shims/dunder-proto/commit/03e6660a1d70dc401f3e217a031475ec537243dd)
diff --git a/server/node_modules/dunder-proto/LICENSE b/server/node_modules/dunder-proto/LICENSE
new file mode 100644
index 0000000..34995e7
--- /dev/null
+++ b/server/node_modules/dunder-proto/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 ECMAScript Shims
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/dunder-proto/README.md b/server/node_modules/dunder-proto/README.md
new file mode 100644
index 0000000..44b80a2
--- /dev/null
+++ b/server/node_modules/dunder-proto/README.md
@@ -0,0 +1,54 @@
+# dunder-proto <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+If available, the `Object.prototype.__proto__` accessor and mutator, call-bound.
+
+## Getting started
+
+```sh
+npm install --save dunder-proto
+```
+
+## Usage/Examples
+
+```js
+const assert = require('assert');
+const getDunder = require('dunder-proto/get');
+const setDunder = require('dunder-proto/set');
+
+const obj = {};
+
+assert.equal('toString' in obj, true);
+assert.equal(getDunder(obj), Object.prototype);
+
+setDunder(obj, null);
+
+assert.equal('toString' in obj, false);
+assert.equal(getDunder(obj), null);
+```
+
+## Tests
+
+Clone the repo, `npm install`, and run `npm test`
+
+[package-url]: https://npmjs.org/package/dunder-proto
+[npm-version-svg]: https://versionbadg.es/es-shims/dunder-proto.svg
+[deps-svg]: https://david-dm.org/es-shims/dunder-proto.svg
+[deps-url]: https://david-dm.org/es-shims/dunder-proto
+[dev-deps-svg]: https://david-dm.org/es-shims/dunder-proto/dev-status.svg
+[dev-deps-url]: https://david-dm.org/es-shims/dunder-proto#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/dunder-proto.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/dunder-proto.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/dunder-proto.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=dunder-proto
+[codecov-image]: https://codecov.io/gh/es-shims/dunder-proto/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/es-shims/dunder-proto/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/es-shims/dunder-proto
+[actions-url]: https://github.com/es-shims/dunder-proto/actions
diff --git a/server/node_modules/dunder-proto/get.d.ts b/server/node_modules/dunder-proto/get.d.ts
new file mode 100644
index 0000000..c7e14d2
--- /dev/null
+++ b/server/node_modules/dunder-proto/get.d.ts
@@ -0,0 +1,5 @@
+declare function getDunderProto(target: {}): object | null;
+
+declare const x: false | typeof getDunderProto;
+
+export = x;
\ No newline at end of file
diff --git a/server/node_modules/dunder-proto/get.js b/server/node_modules/dunder-proto/get.js
new file mode 100644
index 0000000..45093df
--- /dev/null
+++ b/server/node_modules/dunder-proto/get.js
@@ -0,0 +1,30 @@
+'use strict';
+
+var callBind = require('call-bind-apply-helpers');
+var gOPD = require('gopd');
+
+var hasProtoAccessor;
+try {
+	// eslint-disable-next-line no-extra-parens, no-proto
+	hasProtoAccessor = /** @type {{ __proto__?: typeof Array.prototype }} */ ([]).__proto__ === Array.prototype;
+} catch (e) {
+	if (!e || typeof e !== 'object' || !('code' in e) || e.code !== 'ERR_PROTO_ACCESS') {
+		throw e;
+	}
+}
+
+// eslint-disable-next-line no-extra-parens
+var desc = !!hasProtoAccessor && gOPD && gOPD(Object.prototype, /** @type {keyof typeof Object.prototype} */ ('__proto__'));
+
+var $Object = Object;
+var $getPrototypeOf = $Object.getPrototypeOf;
+
+/** @type {import('./get')} */
+module.exports = desc && typeof desc.get === 'function'
+	? callBind([desc.get])
+	: typeof $getPrototypeOf === 'function'
+		? /** @type {import('./get')} */ function getDunder(value) {
+			// eslint-disable-next-line eqeqeq
+			return $getPrototypeOf(value == null ? value : $Object(value));
+		}
+		: false;
diff --git a/server/node_modules/dunder-proto/package.json b/server/node_modules/dunder-proto/package.json
new file mode 100644
index 0000000..04a4036
--- /dev/null
+++ b/server/node_modules/dunder-proto/package.json
@@ -0,0 +1,76 @@
+{
+	"name": "dunder-proto",
+	"version": "1.0.1",
+	"description": "If available, the `Object.prototype.__proto__` accessor and mutator, call-bound",
+	"main": false,
+	"exports": {
+		"./get": "./get.js",
+		"./set": "./set.js",
+		"./package.json": "./package.json"
+	},
+	"sideEffects": false,
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prepublishOnly": "safe-publish-latest",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=.js,.mjs .",
+		"postlint": "tsc -p . && attw -P",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>= 10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/es-shims/dunder-proto.git"
+	},
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/es-shims/dunder-proto/issues"
+	},
+	"homepage": "https://github.com/es-shims/dunder-proto#readme",
+	"dependencies": {
+		"call-bind-apply-helpers": "^1.0.1",
+		"es-errors": "^1.3.0",
+		"gopd": "^1.2.0"
+	},
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.1",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.2",
+		"@types/tape": "^5.7.0",
+		"auto-changelog": "^2.5.0",
+		"encoding": "^0.1.13",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"testling": {
+		"files": "test/index.js"
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/dunder-proto/set.d.ts b/server/node_modules/dunder-proto/set.d.ts
new file mode 100644
index 0000000..16bfdfe
--- /dev/null
+++ b/server/node_modules/dunder-proto/set.d.ts
@@ -0,0 +1,5 @@
+declare function setDunderProto<P extends null | object>(target: {}, proto: P): P;
+
+declare const x: false | typeof setDunderProto;
+
+export = x;
\ No newline at end of file
diff --git a/server/node_modules/dunder-proto/set.js b/server/node_modules/dunder-proto/set.js
new file mode 100644
index 0000000..6085b6e
--- /dev/null
+++ b/server/node_modules/dunder-proto/set.js
@@ -0,0 +1,35 @@
+'use strict';
+
+var callBind = require('call-bind-apply-helpers');
+var gOPD = require('gopd');
+var $TypeError = require('es-errors/type');
+
+/** @type {{ __proto__?: object | null }} */
+var obj = {};
+try {
+	obj.__proto__ = null; // eslint-disable-line no-proto
+} catch (e) {
+	if (!e || typeof e !== 'object' || !('code' in e) || e.code !== 'ERR_PROTO_ACCESS') {
+		throw e;
+	}
+}
+
+var hasProtoMutator = !('toString' in obj);
+
+// eslint-disable-next-line no-extra-parens
+var desc = gOPD && gOPD(Object.prototype, /** @type {keyof typeof Object.prototype} */ ('__proto__'));
+
+/** @type {import('./set')} */
+module.exports = hasProtoMutator && (
+// eslint-disable-next-line no-extra-parens
+	(!!desc && typeof desc.set === 'function' && /** @type {import('./set')} */ (callBind([desc.set])))
+	|| /** @type {import('./set')} */ function setDunder(object, proto) {
+		// this is node v0.10 or older, which doesn't have Object.setPrototypeOf and has undeniable __proto__
+		if (object == null) { // eslint-disable-line eqeqeq
+			throw new $TypeError('set Object.prototype.__proto__ called on null or undefined');
+		}
+		// eslint-disable-next-line no-proto, no-param-reassign, no-extra-parens
+		/** @type {{ __proto__?: object | null }} */ (object).__proto__ = proto;
+		return proto;
+	}
+);
diff --git a/server/node_modules/dunder-proto/test/get.js b/server/node_modules/dunder-proto/test/get.js
new file mode 100644
index 0000000..253f183
--- /dev/null
+++ b/server/node_modules/dunder-proto/test/get.js
@@ -0,0 +1,34 @@
+'use strict';
+
+var test = require('tape');
+
+var getDunderProto = require('../get');
+
+test('getDunderProto', { skip: !getDunderProto }, function (t) {
+	if (!getDunderProto) {
+		throw 'should never happen; this is just for type narrowing'; // eslint-disable-line no-throw-literal
+	}
+
+	// @ts-expect-error
+	t['throws'](function () { getDunderProto(); }, TypeError, 'throws if no argument');
+	// @ts-expect-error
+	t['throws'](function () { getDunderProto(undefined); }, TypeError, 'throws with undefined');
+	// @ts-expect-error
+	t['throws'](function () { getDunderProto(null); }, TypeError, 'throws with null');
+
+	t.equal(getDunderProto({}), Object.prototype);
+	t.equal(getDunderProto([]), Array.prototype);
+	t.equal(getDunderProto(function () {}), Function.prototype);
+	t.equal(getDunderProto(/./g), RegExp.prototype);
+	t.equal(getDunderProto(42), Number.prototype);
+	t.equal(getDunderProto(true), Boolean.prototype);
+	t.equal(getDunderProto('foo'), String.prototype);
+
+	t.end();
+});
+
+test('no dunder proto', { skip: !!getDunderProto }, function (t) {
+	t.notOk('__proto__' in Object.prototype, 'no __proto__ in Object.prototype');
+
+	t.end();
+});
diff --git a/server/node_modules/dunder-proto/test/index.js b/server/node_modules/dunder-proto/test/index.js
new file mode 100644
index 0000000..08ff36f
--- /dev/null
+++ b/server/node_modules/dunder-proto/test/index.js
@@ -0,0 +1,4 @@
+'use strict';
+
+require('./get');
+require('./set');
diff --git a/server/node_modules/dunder-proto/test/set.js b/server/node_modules/dunder-proto/test/set.js
new file mode 100644
index 0000000..c3bfe4d
--- /dev/null
+++ b/server/node_modules/dunder-proto/test/set.js
@@ -0,0 +1,50 @@
+'use strict';
+
+var test = require('tape');
+
+var setDunderProto = require('../set');
+
+test('setDunderProto', { skip: !setDunderProto }, function (t) {
+	if (!setDunderProto) {
+		throw 'should never happen; this is just for type narrowing'; // eslint-disable-line no-throw-literal
+	}
+
+	// @ts-expect-error
+	t['throws'](function () { setDunderProto(); }, TypeError, 'throws if no arguments');
+	// @ts-expect-error
+	t['throws'](function () { setDunderProto(undefined); }, TypeError, 'throws with undefined and nothing');
+	// @ts-expect-error
+	t['throws'](function () { setDunderProto(undefined, undefined); }, TypeError, 'throws with undefined and undefined');
+	// @ts-expect-error
+	t['throws'](function () { setDunderProto(null); }, TypeError, 'throws with null and undefined');
+	// @ts-expect-error
+	t['throws'](function () { setDunderProto(null, undefined); }, TypeError, 'throws with null and undefined');
+
+	/** @type {{ inherited?: boolean }} */
+	var obj = {};
+	t.ok('toString' in obj, 'object initially has toString');
+
+	setDunderProto(obj, null);
+	t.notOk('toString' in obj, 'object no longer has toString');
+
+	t.notOk('inherited' in obj, 'object lacks inherited property');
+	setDunderProto(obj, { inherited: true });
+	t.equal(obj.inherited, true, 'object has inherited property');
+
+	t.end();
+});
+
+test('no dunder proto', { skip: !!setDunderProto }, function (t) {
+	if ('__proto__' in Object.prototype) {
+		t['throws'](
+			// @ts-expect-error
+			function () { ({}).__proto__ = null; }, // eslint-disable-line no-proto
+			Error,
+			'throws when setting Object.prototype.__proto__'
+		);
+	} else {
+		t.notOk('__proto__' in Object.prototype, 'no __proto__ in Object.prototype');
+	}
+
+	t.end();
+});
diff --git a/server/node_modules/dunder-proto/tsconfig.json b/server/node_modules/dunder-proto/tsconfig.json
new file mode 100644
index 0000000..dabbe23
--- /dev/null
+++ b/server/node_modules/dunder-proto/tsconfig.json
@@ -0,0 +1,9 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "ES2021",
+	},
+	"exclude": [
+		"coverage",
+	],
+}
diff --git a/server/node_modules/ee-first/LICENSE b/server/node_modules/ee-first/LICENSE
new file mode 100644
index 0000000..a7ae8ee
--- /dev/null
+++ b/server/node_modules/ee-first/LICENSE
@@ -0,0 +1,22 @@
+
+The MIT License (MIT)
+
+Copyright (c) 2014 Jonathan Ong me@jongleberry.com
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/ee-first/README.md b/server/node_modules/ee-first/README.md
new file mode 100644
index 0000000..cbd2478
--- /dev/null
+++ b/server/node_modules/ee-first/README.md
@@ -0,0 +1,80 @@
+# EE First
+
+[![NPM version][npm-image]][npm-url]
+[![Build status][travis-image]][travis-url]
+[![Test coverage][coveralls-image]][coveralls-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+[![Gittip][gittip-image]][gittip-url]
+
+Get the first event in a set of event emitters and event pairs,
+then clean up after itself.
+
+## Install
+
+```sh
+$ npm install ee-first
+```
+
+## API
+
+```js
+var first = require('ee-first')
+```
+
+### first(arr, listener)
+
+Invoke `listener` on the first event from the list specified in `arr`. `arr` is
+an array of arrays, with each array in the format `[ee, ...event]`. `listener`
+will be called only once, the first time any of the given events are emitted. If
+`error` is one of the listened events, then if that fires first, the `listener`
+will be given the `err` argument.
+
+The `listener` is invoked as `listener(err, ee, event, args)`, where `err` is the
+first argument emitted from an `error` event, if applicable; `ee` is the event
+emitter that fired; `event` is the string event name that fired; and `args` is an
+array of the arguments that were emitted on the event.
+
+```js
+var ee1 = new EventEmitter()
+var ee2 = new EventEmitter()
+
+first([
+  [ee1, 'close', 'end', 'error'],
+  [ee2, 'error']
+], function (err, ee, event, args) {
+  // listener invoked
+})
+```
+
+#### .cancel()
+
+The group of listeners can be cancelled before being invoked and have all the event
+listeners removed from the underlying event emitters.
+
+```js
+var thunk = first([
+  [ee1, 'close', 'end', 'error'],
+  [ee2, 'error']
+], function (err, ee, event, args) {
+  // listener invoked
+})
+
+// cancel and clean up
+thunk.cancel()
+```
+
+[npm-image]: https://img.shields.io/npm/v/ee-first.svg?style=flat-square
+[npm-url]: https://npmjs.org/package/ee-first
+[github-tag]: http://img.shields.io/github/tag/jonathanong/ee-first.svg?style=flat-square
+[github-url]: https://github.com/jonathanong/ee-first/tags
+[travis-image]: https://img.shields.io/travis/jonathanong/ee-first.svg?style=flat-square
+[travis-url]: https://travis-ci.org/jonathanong/ee-first
+[coveralls-image]: https://img.shields.io/coveralls/jonathanong/ee-first.svg?style=flat-square
+[coveralls-url]: https://coveralls.io/r/jonathanong/ee-first?branch=master
+[license-image]: http://img.shields.io/npm/l/ee-first.svg?style=flat-square
+[license-url]: LICENSE.md
+[downloads-image]: http://img.shields.io/npm/dm/ee-first.svg?style=flat-square
+[downloads-url]: https://npmjs.org/package/ee-first
+[gittip-image]: https://img.shields.io/gittip/jonathanong.svg?style=flat-square
+[gittip-url]: https://www.gittip.com/jonathanong/
diff --git a/server/node_modules/ee-first/index.js b/server/node_modules/ee-first/index.js
new file mode 100644
index 0000000..501287c
--- /dev/null
+++ b/server/node_modules/ee-first/index.js
@@ -0,0 +1,95 @@
+/*!
+ * ee-first
+ * Copyright(c) 2014 Jonathan Ong
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = first
+
+/**
+ * Get the first event in a set of event emitters and event pairs.
+ *
+ * @param {array} stuff
+ * @param {function} done
+ * @public
+ */
+
+function first(stuff, done) {
+  if (!Array.isArray(stuff))
+    throw new TypeError('arg must be an array of [ee, events...] arrays')
+
+  var cleanups = []
+
+  for (var i = 0; i < stuff.length; i++) {
+    var arr = stuff[i]
+
+    if (!Array.isArray(arr) || arr.length < 2)
+      throw new TypeError('each array member must be [ee, events...]')
+
+    var ee = arr[0]
+
+    for (var j = 1; j < arr.length; j++) {
+      var event = arr[j]
+      var fn = listener(event, callback)
+
+      // listen to the event
+      ee.on(event, fn)
+      // push this listener to the list of cleanups
+      cleanups.push({
+        ee: ee,
+        event: event,
+        fn: fn,
+      })
+    }
+  }
+
+  function callback() {
+    cleanup()
+    done.apply(null, arguments)
+  }
+
+  function cleanup() {
+    var x
+    for (var i = 0; i < cleanups.length; i++) {
+      x = cleanups[i]
+      x.ee.removeListener(x.event, x.fn)
+    }
+  }
+
+  function thunk(fn) {
+    done = fn
+  }
+
+  thunk.cancel = cleanup
+
+  return thunk
+}
+
+/**
+ * Create the event listener.
+ * @private
+ */
+
+function listener(event, done) {
+  return function onevent(arg1) {
+    var args = new Array(arguments.length)
+    var ee = this
+    var err = event === 'error'
+      ? arg1
+      : null
+
+    // copy args to prevent arguments escaping scope
+    for (var i = 0; i < args.length; i++) {
+      args[i] = arguments[i]
+    }
+
+    done(err, ee, event, args)
+  }
+}
diff --git a/server/node_modules/ee-first/package.json b/server/node_modules/ee-first/package.json
new file mode 100644
index 0000000..b6d0b7d
--- /dev/null
+++ b/server/node_modules/ee-first/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "ee-first",
+  "description": "return the first event in a set of ee/event pairs",
+  "version": "1.1.1",
+  "author": {
+    "name": "Jonathan Ong",
+    "email": "me@jongleberry.com",
+    "url": "http://jongleberry.com",
+    "twitter": "https://twitter.com/jongleberry"
+  },
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>"
+  ],
+  "license": "MIT",
+  "repository": "jonathanong/ee-first",
+  "devDependencies": {
+    "istanbul": "0.3.9",
+    "mocha": "2.2.5"
+  },
+  "files": [
+    "index.js",
+    "LICENSE"
+  ],
+  "scripts": {
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  }
+}
diff --git a/server/node_modules/emoji-regex/LICENSE-MIT.txt b/server/node_modules/emoji-regex/LICENSE-MIT.txt
new file mode 100644
index 0000000..a41e0a7
--- /dev/null
+++ b/server/node_modules/emoji-regex/LICENSE-MIT.txt
@@ -0,0 +1,20 @@
+Copyright Mathias Bynens <https://mathiasbynens.be/>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/emoji-regex/README.md b/server/node_modules/emoji-regex/README.md
new file mode 100644
index 0000000..f10e173
--- /dev/null
+++ b/server/node_modules/emoji-regex/README.md
@@ -0,0 +1,73 @@
+# emoji-regex [![Build status](https://travis-ci.org/mathiasbynens/emoji-regex.svg?branch=master)](https://travis-ci.org/mathiasbynens/emoji-regex)
+
+_emoji-regex_ offers a regular expression to match all emoji symbols (including textual representations of emoji) as per the Unicode Standard.
+
+This repository contains a script that generates this regular expression based on [the data from Unicode v12](https://github.com/mathiasbynens/unicode-12.0.0). Because of this, the regular expression can easily be updated whenever new emoji are added to the Unicode standard.
+
+## Installation
+
+Via [npm](https://www.npmjs.com/):
+
+```bash
+npm install emoji-regex
+```
+
+In [Node.js](https://nodejs.org/):
+
+```js
+const emojiRegex = require('emoji-regex');
+// Note: because the regular expression has the global flag set, this module
+// exports a function that returns the regex rather than exporting the regular
+// expression itself, to make it impossible to (accidentally) mutate the
+// original regular expression.
+
+const text = `
+\u{231A}: ⌚ default emoji presentation character (Emoji_Presentation)
+\u{2194}\u{FE0F}: ↔️ default text presentation character rendered as emoji
+\u{1F469}: 👩 emoji modifier base (Emoji_Modifier_Base)
+\u{1F469}\u{1F3FF}: 👩🏿 emoji modifier base followed by a modifier
+`;
+
+const regex = emojiRegex();
+let match;
+while (match = regex.exec(text)) {
+  const emoji = match[0];
+  console.log(`Matched sequence ${ emoji } — code points: ${ [...emoji].length }`);
+}
+```
+
+Console output:
+
+```
+Matched sequence ⌚ — code points: 1
+Matched sequence ⌚ — code points: 1
+Matched sequence ↔️ — code points: 2
+Matched sequence ↔️ — code points: 2
+Matched sequence 👩 — code points: 1
+Matched sequence 👩 — code points: 1
+Matched sequence 👩🏿 — code points: 2
+Matched sequence 👩🏿 — code points: 2
+```
+
+To match emoji in their textual representation as well (i.e. emoji that are not `Emoji_Presentation` symbols and that aren’t forced to render as emoji by a variation selector), `require` the other regex:
+
+```js
+const emojiRegex = require('emoji-regex/text.js');
+```
+
+Additionally, in environments which support ES2015 Unicode escapes, you may `require` ES2015-style versions of the regexes:
+
+```js
+const emojiRegex = require('emoji-regex/es2015/index.js');
+const emojiRegexText = require('emoji-regex/es2015/text.js');
+```
+
+## Author
+
+| [![twitter/mathias](https://gravatar.com/avatar/24e08a9ea84deb17ae121074d0f17125?s=70)](https://twitter.com/mathias "Follow @mathias on Twitter") |
+|---|
+| [Mathias Bynens](https://mathiasbynens.be/) |
+
+## License
+
+_emoji-regex_ is available under the [MIT](https://mths.be/mit) license.
diff --git a/server/node_modules/emoji-regex/es2015/index.js b/server/node_modules/emoji-regex/es2015/index.js
new file mode 100644
index 0000000..b4cf3dc
--- /dev/null
+++ b/server/node_modules/emoji-regex/es2015/index.js
@@ -0,0 +1,6 @@
+"use strict";
+
+module.exports = () => {
+  // https://mths.be/emoji
+  return /\u{1F3F4}\u{E0067}\u{E0062}(?:\u{E0065}\u{E006E}\u{E0067}|\u{E0073}\u{E0063}\u{E0074}|\u{E0077}\u{E006C}\u{E0073})\u{E007F}|\u{1F468}(?:\u{1F3FC}\u200D(?:\u{1F91D}\u200D\u{1F468}\u{1F3FB}|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FF}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}-\u{1F3FE}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FE}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}-\u{1F3FD}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FD}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}\u{1F3FC}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u200D(?:\u2764\uFE0F\u200D(?:\u{1F48B}\u200D)?\u{1F468}|[\u{1F468}\u{1F469}]\u200D(?:\u{1F466}\u200D\u{1F466}|\u{1F467}\u200D[\u{1F466}\u{1F467}])|\u{1F466}\u200D\u{1F466}|\u{1F467}\u200D[\u{1F466}\u{1F467}]|[\u{1F468}\u{1F469}]\u200D[\u{1F466}\u{1F467}]|[\u2695\u2696\u2708]\uFE0F|[\u{1F466}\u{1F467}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|(?:\u{1F3FB}\u200D[\u2695\u2696\u2708]|\u{1F3FF}\u200D[\u2695\u2696\u2708]|\u{1F3FE}\u200D[\u2695\u2696\u2708]|\u{1F3FD}\u200D[\u2695\u2696\u2708]|\u{1F3FC}\u200D[\u2695\u2696\u2708])\uFE0F|\u{1F3FB}\u200D[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}]|[\u{1F3FB}-\u{1F3FF}])|(?:\u{1F9D1}\u{1F3FB}\u200D\u{1F91D}\u200D\u{1F9D1}|\u{1F469}\u{1F3FC}\u200D\u{1F91D}\u200D\u{1F469})\u{1F3FB}|\u{1F9D1}(?:\u{1F3FF}\u200D\u{1F91D}\u200D\u{1F9D1}[\u{1F3FB}-\u{1F3FF}]|\u200D\u{1F91D}\u200D\u{1F9D1})|(?:\u{1F9D1}\u{1F3FE}\u200D\u{1F91D}\u200D\u{1F9D1}|\u{1F469}\u{1F3FF}\u200D\u{1F91D}\u200D[\u{1F468}\u{1F469}])[\u{1F3FB}-\u{1F3FE}]|(?:\u{1F9D1}\u{1F3FC}\u200D\u{1F91D}\u200D\u{1F9D1}|\u{1F469}\u{1F3FD}\u200D\u{1F91D}\u200D\u{1F469})[\u{1F3FB}\u{1F3FC}]|\u{1F469}(?:\u{1F3FE}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}-\u{1F3FD}\u{1F3FF}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FC}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}\u{1F3FD}-\u{1F3FF}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FB}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FC}-\u{1F3FF}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FD}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}\u{1F3FC}\u{1F3FE}\u{1F3FF}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u200D(?:\u2764\uFE0F\u200D(?:\u{1F48B}\u200D[\u{1F468}\u{1F469}]|[\u{1F468}\u{1F469}])|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FF}\u200D[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F469}\u200D\u{1F469}\u200D(?:\u{1F466}\u200D\u{1F466}|\u{1F467}\u200D[\u{1F466}\u{1F467}])|(?:\u{1F9D1}\u{1F3FD}\u200D\u{1F91D}\u200D\u{1F9D1}|\u{1F469}\u{1F3FE}\u200D\u{1F91D}\u200D\u{1F469})[\u{1F3FB}-\u{1F3FD}]|\u{1F469}\u200D\u{1F466}\u200D\u{1F466}|\u{1F469}\u200D\u{1F469}\u200D[\u{1F466}\u{1F467}]|(?:\u{1F441}\uFE0F\u200D\u{1F5E8}|\u{1F469}(?:\u{1F3FF}\u200D[\u2695\u2696\u2708]|\u{1F3FE}\u200D[\u2695\u2696\u2708]|\u{1F3FC}\u200D[\u2695\u2696\u2708]|\u{1F3FB}\u200D[\u2695\u2696\u2708]|\u{1F3FD}\u200D[\u2695\u2696\u2708]|\u200D[\u2695\u2696\u2708])|(?:[\u26F9\u{1F3CB}\u{1F3CC}\u{1F575}]\uFE0F|[\u{1F46F}\u{1F93C}\u{1F9DE}\u{1F9DF}])\u200D[\u2640\u2642]|[\u26F9\u{1F3CB}\u{1F3CC}\u{1F575}][\u{1F3FB}-\u{1F3FF}]\u200D[\u2640\u2642]|[\u{1F3C3}\u{1F3C4}\u{1F3CA}\u{1F46E}\u{1F471}\u{1F473}\u{1F477}\u{1F481}\u{1F482}\u{1F486}\u{1F487}\u{1F645}-\u{1F647}\u{1F64B}\u{1F64D}\u{1F64E}\u{1F6A3}\u{1F6B4}-\u{1F6B6}\u{1F926}\u{1F937}-\u{1F939}\u{1F93D}\u{1F93E}\u{1F9B8}\u{1F9B9}\u{1F9CD}-\u{1F9CF}\u{1F9D6}-\u{1F9DD}](?:[\u{1F3FB}-\u{1F3FF}]\u200D[\u2640\u2642]|\u200D[\u2640\u2642])|\u{1F3F4}\u200D\u2620)\uFE0F|\u{1F469}\u200D\u{1F467}\u200D[\u{1F466}\u{1F467}]|\u{1F3F3}\uFE0F\u200D\u{1F308}|\u{1F415}\u200D\u{1F9BA}|\u{1F469}\u200D\u{1F466}|\u{1F469}\u200D\u{1F467}|\u{1F1FD}\u{1F1F0}|\u{1F1F4}\u{1F1F2}|\u{1F1F6}\u{1F1E6}|[#\*0-9]\uFE0F\u20E3|\u{1F1E7}[\u{1F1E6}\u{1F1E7}\u{1F1E9}-\u{1F1EF}\u{1F1F1}-\u{1F1F4}\u{1F1F6}-\u{1F1F9}\u{1F1FB}\u{1F1FC}\u{1F1FE}\u{1F1FF}]|\u{1F1F9}[\u{1F1E6}\u{1F1E8}\u{1F1E9}\u{1F1EB}-\u{1F1ED}\u{1F1EF}-\u{1F1F4}\u{1F1F7}\u{1F1F9}\u{1F1FB}\u{1F1FC}\u{1F1FF}]|\u{1F1EA}[\u{1F1E6}\u{1F1E8}\u{1F1EA}\u{1F1EC}\u{1F1ED}\u{1F1F7}-\u{1F1FA}]|\u{1F9D1}[\u{1F3FB}-\u{1F3FF}]|\u{1F1F7}[\u{1F1EA}\u{1F1F4}\u{1F1F8}\u{1F1FA}\u{1F1FC}]|\u{1F469}[\u{1F3FB}-\u{1F3FF}]|\u{1F1F2}[\u{1F1E6}\u{1F1E8}-\u{1F1ED}\u{1F1F0}-\u{1F1FF}]|\u{1F1E6}[\u{1F1E8}-\u{1F1EC}\u{1F1EE}\u{1F1F1}\u{1F1F2}\u{1F1F4}\u{1F1F6}-\u{1F1FA}\u{1F1FC}\u{1F1FD}\u{1F1FF}]|\u{1F1F0}[\u{1F1EA}\u{1F1EC}-\u{1F1EE}\u{1F1F2}\u{1F1F3}\u{1F1F5}\u{1F1F7}\u{1F1FC}\u{1F1FE}\u{1F1FF}]|\u{1F1ED}[\u{1F1F0}\u{1F1F2}\u{1F1F3}\u{1F1F7}\u{1F1F9}\u{1F1FA}]|\u{1F1E9}[\u{1F1EA}\u{1F1EC}\u{1F1EF}\u{1F1F0}\u{1F1F2}\u{1F1F4}\u{1F1FF}]|\u{1F1FE}[\u{1F1EA}\u{1F1F9}]|\u{1F1EC}[\u{1F1E6}\u{1F1E7}\u{1F1E9}-\u{1F1EE}\u{1F1F1}-\u{1F1F3}\u{1F1F5}-\u{1F1FA}\u{1F1FC}\u{1F1FE}]|\u{1F1F8}[\u{1F1E6}-\u{1F1EA}\u{1F1EC}-\u{1F1F4}\u{1F1F7}-\u{1F1F9}\u{1F1FB}\u{1F1FD}-\u{1F1FF}]|\u{1F1EB}[\u{1F1EE}-\u{1F1F0}\u{1F1F2}\u{1F1F4}\u{1F1F7}]|\u{1F1F5}[\u{1F1E6}\u{1F1EA}-\u{1F1ED}\u{1F1F0}-\u{1F1F3}\u{1F1F7}-\u{1F1F9}\u{1F1FC}\u{1F1FE}]|\u{1F1FB}[\u{1F1E6}\u{1F1E8}\u{1F1EA}\u{1F1EC}\u{1F1EE}\u{1F1F3}\u{1F1FA}]|\u{1F1F3}[\u{1F1E6}\u{1F1E8}\u{1F1EA}-\u{1F1EC}\u{1F1EE}\u{1F1F1}\u{1F1F4}\u{1F1F5}\u{1F1F7}\u{1F1FA}\u{1F1FF}]|\u{1F1E8}[\u{1F1E6}\u{1F1E8}\u{1F1E9}\u{1F1EB}-\u{1F1EE}\u{1F1F0}-\u{1F1F5}\u{1F1F7}\u{1F1FA}-\u{1F1FF}]|\u{1F1F1}[\u{1F1E6}-\u{1F1E8}\u{1F1EE}\u{1F1F0}\u{1F1F7}-\u{1F1FB}\u{1F1FE}]|\u{1F1FF}[\u{1F1E6}\u{1F1F2}\u{1F1FC}]|\u{1F1FC}[\u{1F1EB}\u{1F1F8}]|\u{1F1FA}[\u{1F1E6}\u{1F1EC}\u{1F1F2}\u{1F1F3}\u{1F1F8}\u{1F1FE}\u{1F1FF}]|\u{1F1EE}[\u{1F1E8}-\u{1F1EA}\u{1F1F1}-\u{1F1F4}\u{1F1F6}-\u{1F1F9}]|\u{1F1EF}[\u{1F1EA}\u{1F1F2}\u{1F1F4}\u{1F1F5}]|[\u{1F3C3}\u{1F3C4}\u{1F3CA}\u{1F46E}\u{1F471}\u{1F473}\u{1F477}\u{1F481}\u{1F482}\u{1F486}\u{1F487}\u{1F645}-\u{1F647}\u{1F64B}\u{1F64D}\u{1F64E}\u{1F6A3}\u{1F6B4}-\u{1F6B6}\u{1F926}\u{1F937}-\u{1F939}\u{1F93D}\u{1F93E}\u{1F9B8}\u{1F9B9}\u{1F9CD}-\u{1F9CF}\u{1F9D6}-\u{1F9DD}][\u{1F3FB}-\u{1F3FF}]|[\u26F9\u{1F3CB}\u{1F3CC}\u{1F575}][\u{1F3FB}-\u{1F3FF}]|[\u261D\u270A-\u270D\u{1F385}\u{1F3C2}\u{1F3C7}\u{1F442}\u{1F443}\u{1F446}-\u{1F450}\u{1F466}\u{1F467}\u{1F46B}-\u{1F46D}\u{1F470}\u{1F472}\u{1F474}-\u{1F476}\u{1F478}\u{1F47C}\u{1F483}\u{1F485}\u{1F4AA}\u{1F574}\u{1F57A}\u{1F590}\u{1F595}\u{1F596}\u{1F64C}\u{1F64F}\u{1F6C0}\u{1F6CC}\u{1F90F}\u{1F918}-\u{1F91C}\u{1F91E}\u{1F91F}\u{1F930}-\u{1F936}\u{1F9B5}\u{1F9B6}\u{1F9BB}\u{1F9D2}-\u{1F9D5}][\u{1F3FB}-\u{1F3FF}]|[\u231A\u231B\u23E9-\u23EC\u23F0\u23F3\u25FD\u25FE\u2614\u2615\u2648-\u2653\u267F\u2693\u26A1\u26AA\u26AB\u26BD\u26BE\u26C4\u26C5\u26CE\u26D4\u26EA\u26F2\u26F3\u26F5\u26FA\u26FD\u2705\u270A\u270B\u2728\u274C\u274E\u2753-\u2755\u2757\u2795-\u2797\u27B0\u27BF\u2B1B\u2B1C\u2B50\u2B55\u{1F004}\u{1F0CF}\u{1F18E}\u{1F191}-\u{1F19A}\u{1F1E6}-\u{1F1FF}\u{1F201}\u{1F21A}\u{1F22F}\u{1F232}-\u{1F236}\u{1F238}-\u{1F23A}\u{1F250}\u{1F251}\u{1F300}-\u{1F320}\u{1F32D}-\u{1F335}\u{1F337}-\u{1F37C}\u{1F37E}-\u{1F393}\u{1F3A0}-\u{1F3CA}\u{1F3CF}-\u{1F3D3}\u{1F3E0}-\u{1F3F0}\u{1F3F4}\u{1F3F8}-\u{1F43E}\u{1F440}\u{1F442}-\u{1F4FC}\u{1F4FF}-\u{1F53D}\u{1F54B}-\u{1F54E}\u{1F550}-\u{1F567}\u{1F57A}\u{1F595}\u{1F596}\u{1F5A4}\u{1F5FB}-\u{1F64F}\u{1F680}-\u{1F6C5}\u{1F6CC}\u{1F6D0}-\u{1F6D2}\u{1F6D5}\u{1F6EB}\u{1F6EC}\u{1F6F4}-\u{1F6FA}\u{1F7E0}-\u{1F7EB}\u{1F90D}-\u{1F93A}\u{1F93C}-\u{1F945}\u{1F947}-\u{1F971}\u{1F973}-\u{1F976}\u{1F97A}-\u{1F9A2}\u{1F9A5}-\u{1F9AA}\u{1F9AE}-\u{1F9CA}\u{1F9CD}-\u{1F9FF}\u{1FA70}-\u{1FA73}\u{1FA78}-\u{1FA7A}\u{1FA80}-\u{1FA82}\u{1FA90}-\u{1FA95}]|[#\*0-9\xA9\xAE\u203C\u2049\u2122\u2139\u2194-\u2199\u21A9\u21AA\u231A\u231B\u2328\u23CF\u23E9-\u23F3\u23F8-\u23FA\u24C2\u25AA\u25AB\u25B6\u25C0\u25FB-\u25FE\u2600-\u2604\u260E\u2611\u2614\u2615\u2618\u261D\u2620\u2622\u2623\u2626\u262A\u262E\u262F\u2638-\u263A\u2640\u2642\u2648-\u2653\u265F\u2660\u2663\u2665\u2666\u2668\u267B\u267E\u267F\u2692-\u2697\u2699\u269B\u269C\u26A0\u26A1\u26AA\u26AB\u26B0\u26B1\u26BD\u26BE\u26C4\u26C5\u26C8\u26CE\u26CF\u26D1\u26D3\u26D4\u26E9\u26EA\u26F0-\u26F5\u26F7-\u26FA\u26FD\u2702\u2705\u2708-\u270D\u270F\u2712\u2714\u2716\u271D\u2721\u2728\u2733\u2734\u2744\u2747\u274C\u274E\u2753-\u2755\u2757\u2763\u2764\u2795-\u2797\u27A1\u27B0\u27BF\u2934\u2935\u2B05-\u2B07\u2B1B\u2B1C\u2B50\u2B55\u3030\u303D\u3297\u3299\u{1F004}\u{1F0CF}\u{1F170}\u{1F171}\u{1F17E}\u{1F17F}\u{1F18E}\u{1F191}-\u{1F19A}\u{1F1E6}-\u{1F1FF}\u{1F201}\u{1F202}\u{1F21A}\u{1F22F}\u{1F232}-\u{1F23A}\u{1F250}\u{1F251}\u{1F300}-\u{1F321}\u{1F324}-\u{1F393}\u{1F396}\u{1F397}\u{1F399}-\u{1F39B}\u{1F39E}-\u{1F3F0}\u{1F3F3}-\u{1F3F5}\u{1F3F7}-\u{1F4FD}\u{1F4FF}-\u{1F53D}\u{1F549}-\u{1F54E}\u{1F550}-\u{1F567}\u{1F56F}\u{1F570}\u{1F573}-\u{1F57A}\u{1F587}\u{1F58A}-\u{1F58D}\u{1F590}\u{1F595}\u{1F596}\u{1F5A4}\u{1F5A5}\u{1F5A8}\u{1F5B1}\u{1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+};
diff --git a/server/node_modules/emoji-regex/es2015/text.js b/server/node_modules/emoji-regex/es2015/text.js
new file mode 100644
index 0000000..780309d
--- /dev/null
+++ b/server/node_modules/emoji-regex/es2015/text.js
@@ -0,0 +1,6 @@
+"use strict";
+
+module.exports = () => {
+  // https://mths.be/emoji
+  return /\u{1F3F4}\u{E0067}\u{E0062}(?:\u{E0065}\u{E006E}\u{E0067}|\u{E0073}\u{E0063}\u{E0074}|\u{E0077}\u{E006C}\u{E0073})\u{E007F}|\u{1F468}(?:\u{1F3FC}\u200D(?:\u{1F91D}\u200D\u{1F468}\u{1F3FB}|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FF}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}-\u{1F3FE}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FE}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}-\u{1F3FD}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FD}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}\u{1F3FC}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u200D(?:\u2764\uFE0F\u200D(?:\u{1F48B}\u200D)?\u{1F468}|[\u{1F468}\u{1F469}]\u200D(?:\u{1F466}\u200D\u{1F466}|\u{1F467}\u200D[\u{1F466}\u{1F467}])|\u{1F466}\u200D\u{1F466}|\u{1F467}\u200D[\u{1F466}\u{1F467}]|[\u{1F468}\u{1F469}]\u200D[\u{1F466}\u{1F467}]|[\u2695\u2696\u2708]\uFE0F|[\u{1F466}\u{1F467}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|(?:\u{1F3FB}\u200D[\u2695\u2696\u2708]|\u{1F3FF}\u200D[\u2695\u2696\u2708]|\u{1F3FE}\u200D[\u2695\u2696\u2708]|\u{1F3FD}\u200D[\u2695\u2696\u2708]|\u{1F3FC}\u200D[\u2695\u2696\u2708])\uFE0F|\u{1F3FB}\u200D[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}]|[\u{1F3FB}-\u{1F3FF}])|(?:\u{1F9D1}\u{1F3FB}\u200D\u{1F91D}\u200D\u{1F9D1}|\u{1F469}\u{1F3FC}\u200D\u{1F91D}\u200D\u{1F469})\u{1F3FB}|\u{1F9D1}(?:\u{1F3FF}\u200D\u{1F91D}\u200D\u{1F9D1}[\u{1F3FB}-\u{1F3FF}]|\u200D\u{1F91D}\u200D\u{1F9D1})|(?:\u{1F9D1}\u{1F3FE}\u200D\u{1F91D}\u200D\u{1F9D1}|\u{1F469}\u{1F3FF}\u200D\u{1F91D}\u200D[\u{1F468}\u{1F469}])[\u{1F3FB}-\u{1F3FE}]|(?:\u{1F9D1}\u{1F3FC}\u200D\u{1F91D}\u200D\u{1F9D1}|\u{1F469}\u{1F3FD}\u200D\u{1F91D}\u200D\u{1F469})[\u{1F3FB}\u{1F3FC}]|\u{1F469}(?:\u{1F3FE}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}-\u{1F3FD}\u{1F3FF}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FC}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}\u{1F3FD}-\u{1F3FF}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FB}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FC}-\u{1F3FF}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FD}\u200D(?:\u{1F91D}\u200D\u{1F468}[\u{1F3FB}\u{1F3FC}\u{1F3FE}\u{1F3FF}]|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u200D(?:\u2764\uFE0F\u200D(?:\u{1F48B}\u200D[\u{1F468}\u{1F469}]|[\u{1F468}\u{1F469}])|[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F3FF}\u200D[\u{1F33E}\u{1F373}\u{1F393}\u{1F3A4}\u{1F3A8}\u{1F3EB}\u{1F3ED}\u{1F4BB}\u{1F4BC}\u{1F527}\u{1F52C}\u{1F680}\u{1F692}\u{1F9AF}-\u{1F9B3}\u{1F9BC}\u{1F9BD}])|\u{1F469}\u200D\u{1F469}\u200D(?:\u{1F466}\u200D\u{1F466}|\u{1F467}\u200D[\u{1F466}\u{1F467}])|(?:\u{1F9D1}\u{1F3FD}\u200D\u{1F91D}\u200D\u{1F9D1}|\u{1F469}\u{1F3FE}\u200D\u{1F91D}\u200D\u{1F469})[\u{1F3FB}-\u{1F3FD}]|\u{1F469}\u200D\u{1F466}\u200D\u{1F466}|\u{1F469}\u200D\u{1F469}\u200D[\u{1F466}\u{1F467}]|(?:\u{1F441}\uFE0F\u200D\u{1F5E8}|\u{1F469}(?:\u{1F3FF}\u200D[\u2695\u2696\u2708]|\u{1F3FE}\u200D[\u2695\u2696\u2708]|\u{1F3FC}\u200D[\u2695\u2696\u2708]|\u{1F3FB}\u200D[\u2695\u2696\u2708]|\u{1F3FD}\u200D[\u2695\u2696\u2708]|\u200D[\u2695\u2696\u2708])|(?:[\u26F9\u{1F3CB}\u{1F3CC}\u{1F575}]\uFE0F|[\u{1F46F}\u{1F93C}\u{1F9DE}\u{1F9DF}])\u200D[\u2640\u2642]|[\u26F9\u{1F3CB}\u{1F3CC}\u{1F575}][\u{1F3FB}-\u{1F3FF}]\u200D[\u2640\u2642]|[\u{1F3C3}\u{1F3C4}\u{1F3CA}\u{1F46E}\u{1F471}\u{1F473}\u{1F477}\u{1F481}\u{1F482}\u{1F486}\u{1F487}\u{1F645}-\u{1F647}\u{1F64B}\u{1F64D}\u{1F64E}\u{1F6A3}\u{1F6B4}-\u{1F6B6}\u{1F926}\u{1F937}-\u{1F939}\u{1F93D}\u{1F93E}\u{1F9B8}\u{1F9B9}\u{1F9CD}-\u{1F9CF}\u{1F9D6}-\u{1F9DD}](?:[\u{1F3FB}-\u{1F3FF}]\u200D[\u2640\u2642]|\u200D[\u2640\u2642])|\u{1F3F4}\u200D\u2620)\uFE0F|\u{1F469}\u200D\u{1F467}\u200D[\u{1F466}\u{1F467}]|\u{1F3F3}\uFE0F\u200D\u{1F308}|\u{1F415}\u200D\u{1F9BA}|\u{1F469}\u200D\u{1F466}|\u{1F469}\u200D\u{1F467}|\u{1F1FD}\u{1F1F0}|\u{1F1F4}\u{1F1F2}|\u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+};
diff --git a/server/node_modules/emoji-regex/index.d.ts b/server/node_modules/emoji-regex/index.d.ts
new file mode 100644
index 0000000..1955b47
--- /dev/null
+++ b/server/node_modules/emoji-regex/index.d.ts
@@ -0,0 +1,23 @@
+declare module 'emoji-regex' {
+    function emojiRegex(): RegExp;
+
+    export default emojiRegex;
+}
+
+declare module 'emoji-regex/text' {
+    function emojiRegex(): RegExp;
+
+    export default emojiRegex;
+}
+
+declare module 'emoji-regex/es2015' {
+    function emojiRegex(): RegExp;
+
+    export default emojiRegex;
+}
+
+declare module 'emoji-regex/es2015/text' {
+    function emojiRegex(): RegExp;
+
+    export default emojiRegex;
+}
diff --git a/server/node_modules/emoji-regex/index.js b/server/node_modules/emoji-regex/index.js
new file mode 100644
index 0000000..d993a3a
--- /dev/null
+++ b/server/node_modules/emoji-regex/index.js
@@ -0,0 +1,6 @@
+"use strict";
+
+module.exports = function () {
+  // https://mths.be/emoji
+  return /\uD83C\uDFF4\uDB40\uDC67\uDB40\uDC62(?:\uDB40\uDC65\uDB40\uDC6E\uDB40\uDC67|\uDB40\uDC73\uDB40\uDC63\uDB40\uDC74|\uDB40\uDC77\uDB40\uDC6C\uDB40\uDC73)\uDB40\uDC7F|\uD83D\uDC68(?:\uD83C\uDFFC\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68\uD83C\uDFFB|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFF\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB-\uDFFE])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFE\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB-\uDFFD])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFD\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB\uDFFC])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\u200D(?:\u2764\uFE0F\u200D(?:\uD83D\uDC8B\u200D)?\uD83D\uDC68|(?:\uD83D[\uDC68\uDC69])\u200D(?:\uD83D\uDC66\u200D\uD83D\uDC66|\uD83D\uDC67\u200D(?:\uD83D[\uDC66\uDC67]))|\uD83D\uDC66\u200D\uD83D\uDC66|\uD83D\uDC67\u200D(?:\uD83D[\uDC66\uDC67])|(?:\uD83D[\uDC68\uDC69])\u200D(?:\uD83D[\uDC66\uDC67])|[\u2695\u2696\u2708]\uFE0F|\uD83D[\uDC66\uDC67]|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|(?:\uD83C\uDFFB\u200D[\u2695\u2696\u2708]|\uD83C\uDFFF\u200D[\u2695\u2696\u2708]|\uD83C\uDFFE\u200D[\u2695\u2696\u2708]|\uD83C\uDFFD\u200D[\u2695\u2696\u2708]|\uD83C\uDFFC\u200D[\u2695\u2696\u2708])\uFE0F|\uD83C\uDFFB\u200D(?:\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C[\uDFFB-\uDFFF])|(?:\uD83E\uDDD1\uD83C\uDFFB\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1|\uD83D\uDC69\uD83C\uDFFC\u200D\uD83E\uDD1D\u200D\uD83D\uDC69)\uD83C\uDFFB|\uD83E\uDDD1(?:\uD83C\uDFFF\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1(?:\uD83C[\uDFFB-\uDFFF])|\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1)|(?:\uD83E\uDDD1\uD83C\uDFFE\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1|\uD83D\uDC69\uD83C\uDFFF\u200D\uD83E\uDD1D\u200D(?:\uD83D[\uDC68\uDC69]))(?:\uD83C[\uDFFB-\uDFFE])|(?:\uD83E\uDDD1\uD83C\uDFFC\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1|\uD83D\uDC69\uD83C\uDFFD\u200D\uD83E\uDD1D\u200D\uD83D\uDC69)(?:\uD83C[\uDFFB\uDFFC])|\uD83D\uDC69(?:\uD83C\uDFFE\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB-\uDFFD\uDFFF])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFC\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB\uDFFD-\uDFFF])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFB\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFC-\uDFFF])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFD\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB\uDFFC\uDFFE\uDFFF])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\u200D(?:\u2764\uFE0F\u200D(?:\uD83D\uDC8B\u200D(?:\uD83D[\uDC68\uDC69])|\uD83D[\uDC68\uDC69])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFF\u200D(?:\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD]))|\uD83D\uDC69\u200D\uD83D\uDC69\u200D(?:\uD83D\uDC66\u200D\uD83D\uDC66|\uD83D\uDC67\u200D(?:\uD83D[\uDC66\uDC67]))|(?:\uD83E\uDDD1\uD83C\uDFFD\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1|\uD83D\uDC69\uD83C\uDFFE\u200D\uD83E\uDD1D\u200D\uD83D\uDC69)(?:\uD83C[\uDFFB-\uDFFD])|\uD83D\uDC69\u200D\uD83D\uDC66\u200D\uD83D\uDC66|\uD83D\uDC69\u200D\uD83D\uDC69\u200D(?:\uD83D[\uDC66\uDC67])|(?:\uD83D\uDC41\uFE0F\u200D\uD83D\uDDE8|\uD83D\uDC69(?:\uD83C\uDFFF\u200D[\u2695\u2696\u2708]|\uD83C\uDFFE\u200D[\u2695\u2696\u2708]|\uD83C\uDFFC\u200D[\u2695\u2696\u2708]|\uD83C\uDFFB\u200D[\u2695\u2696\u2708]|\uD83C\uDFFD\u200D[\u2695\u2696\u2708]|\u200D[\u2695\u2696\u2708])|(?:(?:\u26F9|\uD83C[\uDFCB\uDFCC]|\uD83D\uDD75)\uFE0F|\uD83D\uDC6F|\uD83E[\uDD3C\uDDDE\uDDDF])\u200D[\u2640\u2642]|(?:\u26F9|\uD83C[\uDFCB\uDFCC]|\uD83D\uDD75)(?:\uD83C[\uDFFB-\uDFFF])\u200D[\u2640\u2642]|(?:\uD83C[\uDFC3\uDFC4\uDFCA]|\uD83D[\uDC6E\uDC71\uDC73\uDC77\uDC81\uDC82\uDC86\uDC87\uDE45-\uDE47\uDE4B\uDE4D\uDE4E\uDEA3\uDEB4-\uDEB6]|\uD83E[\uDD26\uDD37-\uDD39\uDD3D\uDD3E\uDDB8\uDDB9\uDDCD-\uDDCF\uDDD6-\uDDDD])(?:(?:\uD83C[\uDFFB-\uDFFF])\u200D[\u2640\u2642]|\u200D[\u2640\u2642])|\uD83C\uDFF4\u200D\u2620)\uFE0F|\uD83D\uDC69\u200D\uD83D\uDC67\u200D(?:\uD83D[\uDC66\uDC67])|\uD83C\uDFF3\uFE0F\u200D\uD83C\uDF08|\uD83D\uDC15\u200D\uD83E\uDDBA|\uD83D\uDC69\u200D\uD83D\uDC66|\uD83D\uDC69\u200D\uD83D\uDC67|\uD83C\uDDFD\uD83C\uDDF0|\uD83C\uDDF4\uD83C\uDDF2|\uD83C\uDDF6\uD83C\uDDE6|[#\*0-9]\uFE0F\u20E3|\uD83C\uDDE7(?:\uD83C[\uDDE6\uDDE7\uDDE9-\uDDEF\uDDF1-\uDDF4\uDDF6-\uDDF9\uDDFB\uDDFC\uDDFE\uDDFF])|\uD83C\uDDF9(?:\uD83C[\uDDE6\uDDE8\uDDE9\uDDEB-\uDDED\uDDEF-\uDDF4\uDDF7\uDDF9\uDDFB\uDDFC\uDDFF])|\uD83C\uDDEA(?:\uD83C[\uDDE6\uDDE8\uDDEA\uDDEC\uDDED\uDDF7-\uDDFA])|\uD83E\uDDD1(?:\uD83C[\uDFFB-\uDFFF])|\uD83C\uDDF7(?:\uD83C[\uDDEA\uDDF4\uDDF8\uDDFA\uDDFC])|\uD83D\uDC69(?:\uD83C[\uDFFB-\uDFFF])|\uD83C\uDDF2(?:\uD83C[\uDDE6\uDDE8-\uDDED\uDDF0-\uDDFF])|\uD83C\uDDE6(?:\uD83C[\uDDE8-\uDDEC\uDDEE\uDDF1\uDDF2\uDDF4\uDDF6-\uDDFA\uDDFC\uDDFD\uDDFF])|\uD83C\uDDF0(?:\uD83C[\uDDEA\uDDEC-\uDDEE\uDDF2\uDDF3\uDDF5\uDDF7\uDDFC\uDDFE\uDDFF])|\uD83C\uDDED(?:\uD83C[\uDDF0\uDDF2\uDDF3\uDDF7\uDDF9\uDDFA])|\uD83C\uDDE9(?:\uD83C[\uDDEA\uDDEC\uDDEF\uDDF0\uDDF2\uDDF4\uDDFF])|\uD83C\uDDFE(?:\uD83C[\uDDEA\uDDF9])|\uD83C\uDDEC(?:\uD83C[\uDDE6\uDDE7\uDDE9-\uDDEE\uDDF1-\uDDF3\uDDF5-\uDDFA\uDDFC\uDDFE])|\uD83C\uDDF8(?:\uD83C[\uDDE6-\uDDEA\uDDEC-\uDDF4\uDDF7-\uDDF9\uDDFB\uDDFD-\uDDFF])|\uD83C\uDDEB(?:\uD83C[\uDDEE-\uDDF0\uDDF2\uDDF4\uDDF7])|\uD83C\uDDF5(?:\uD83C[\uDDE6\uDDEA-\uDDED\uDDF0-\uDDF3\uDDF7-\uDDF9\uDDFC\uDDFE])|\uD83C\uDDFB(?:\uD83C[\uDDE6\uDDE8\uDDEA\uDDEC\uDDEE\uDDF3\uDDFA])|\uD83C\uDDF3(?:\uD83C[\uDDE6\uDDE8\uDDEA-\uDDEC\uDDEE\uDDF1\uDDF4\uDDF5\uDDF7\uDDFA\uDDFF])|\uD83C\uDDE8(?:\uD83C[\uDDE6\uDDE8\uDDE9\uDDEB-\uDDEE\uDDF0-\uDDF5\uDDF7\uDDFA-\uDDFF])|\uD83C\uDDF1(?:\uD83C[\uDDE6-\uDDE8\uDDEE\uDDF0\uDDF7-\uDDFB\uDDFE])|\uD83C\uDDFF(?:\uD83C[\uDDE6\uDDF2\uDDFC])|\uD83C\uDDFC(?:\uD83C[\uDDEB\uDDF8])|\uD83C\uDDFA(?:\uD83C[\uDDE6\uDDEC\uDDF2\uDDF3\uDDF8\uDDFE\uDDFF])|\uD83C\uDDEE(?:\uD83C[\uDDE8-\uDDEA\uDDF1-\uDDF4\uDDF6-\uDDF9])|\uD83C\uDDEF(?:\uD83C[\uDDEA\uDDF2\uDDF4\uDDF5])|(?:\uD83C[\uDFC3\uDFC4\uDFCA]|\uD83D[\uDC6E\uDC71\uDC73\uDC77\uDC81\uDC82\uDC86\uDC87\uDE45-\uDE47\uDE4B\uDE4D\uDE4E\uDEA3\uDEB4-\uDEB6]|\uD83E[\uDD26\uDD37-\uDD39\uDD3D\uDD3E\uDDB8\uDDB9\uDDCD-\uDDCF\uDDD6-\uDDDD])(?:\uD83C[\uDFFB-\uDFFF])|(?:\u26F9|\uD83C[\uDFCB\uDFCC]|\uD83D\uDD75)(?:\uD83C[\uDFFB-\uDFFF])|(?:[\u261D\u270A-\u270D]|\uD83C[\uDF85\uDFC2\uDFC7]|\uD83D[\uDC42\uDC43\uDC46-\uDC50\uDC66\uDC67\uDC6B-\uDC6D\uDC70\uDC72\uDC74-\uDC76\uDC78\uDC7C\uDC83\uDC85\uDCAA\uDD74\uDD7A\uDD90\uDD95\uDD96\uDE4C\uDE4F\uDEC0\uDECC]|\uD83E[\uDD0F\uDD18-\uDD1C\uDD1E\uDD1F\uDD30-\uDD36\uDDB5\uDDB6\uDDBB\uDDD2-\uDDD5])(?:\uD83C[\uDFFB-\uDFFF])|(?:[\u231A\u231B\u23E9-\u23EC\u23F0\u23F3\u25FD\u25FE\u2614\u2615\u2648-\u2653\u267F\u2693\u26A1\u26AA\u26AB\u26BD\u26BE\u26C4\u26C5\u26CE\u26D4\u26EA\u26F2\u26F3\u26F5\u26FA\u26FD\u2705\u270A\u270B\u2728\u274C\u274E\u2753-\u2755\u2757\u2795-\u2797\u27B0\u27BF\u2B1B\u2B1C\u2B50\u2B55]|\uD83C[\uDC04\uDCCF\uDD8E\uDD91-\uDD9A\uDDE6-\uDDFF\uDE01\uDE1A\uDE2F\uDE32-\uDE36\uDE38-\uDE3A\uDE50\uDE51\uDF00-\uDF20\uDF2D-\uDF35\uDF37-\uDF7C\uDF7E-\uDF93\uDFA0-\uDFCA\uDFCF-\uDFD3\uDFE0-\uDFF0\uDFF4\uDFF8-\uDFFF]|\uD83D[\uDC00-\uDC3E\uDC40\uDC42-\uDCFC\uDCFF-\uDD3D\uDD4B-\uDD4E\uDD50-\uDD67\uDD7A\uDD95\uDD96\uDDA4\uDDFB-\uDE4F\uDE80-\uDEC5\uDECC\uDED0-\uDED2\uDED5\uDEEB\uDEEC\uDEF4-\uDEFA\uDFE0-\uDFEB]|\uD83E[\uDD0D-\uDD3A\uDD3C-\uDD45\uDD47-\uDD71\uDD73-\uDD76\uDD7A-\uDDA2\uDDA5-\uDDAA\uDDAE-\uDDCA\uDDCD-\uDDFF\uDE70-\uDE73\uDE78-\uDE7A\uDE80-\uDE82\uDE90-\uDE95])|(?:[#\*0-9\xA9\xAE\u203C\u2049\u2122\u2139\u2194-\u2199\u21A9\u21AA\u231A\u231B\u2328\u23CF\u23E9-\u23F3\u23F8-\u23FA\u24C2\u25AA\u25AB\u25B6\u25C0\u25FB-\u25FE\u2600-\u2604\u260E\u2611\u2614\u2615\u2618\u261D\u2620\u2622\u2623\u2626\u262A\u262E\u262F\u2638-\u263A\u2640\u2642\u2648-\u2653\u265F\u2660\u2663\u2665\u2666\u2668\u267B\u267E\u267F\u2692-\u2697\u2699\u269B\u269C\u26A0\u26A1\u26AA\u26AB\u26B0\u26B1\u26BD\u26BE\u26C4\u26C5\u26C8\u26CE\u26CF\u26D1\u26D3\u26D4\u26E9\u26EA\u26F0-\u26F5\u26F7-\u26FA\u26FD\u2702\u2705\u2708-\u270D\u270F\u2712\u2714\u2716\u271D\u2721\u2728\u2733\u2734\u2744\u2747\u274C\u274E\u2753-\u2755\u2757\u2763\u2764\u2795-\u2797\u27A1\u27B0\u27BF\u2934\u2935\u2B05-\u2B07\u2B1B\u2B1C\u2B50\u2B55\u3030\u303D\u3297\u3299]|\uD83C[\uDC04\uDCCF\uDD70\uDD71\uDD7E\uDD7F\uDD8E\uDD91-\uDD9A\uDDE6-\uDDFF\uDE01\uDE02\uDE1A\uDE2F\uDE32-\uDE3A\uDE50\uDE51\uDF00-\uDF21\uDF24-\uDF93\uDF96\uDF97\uDF99-\uDF9B\uDF9E-\uDFF0\uDFF3-\uDFF5\uDFF7-\uDFFF]|\uD83D[\uDC00-\uDCFD\uDCFF-\uDD3D\uDD49-\uDD4E\uDD50-\uDD67\uDD6F\uDD70\uDD73-\uDD7A\uDD87\uDD8A-\uDD8D\uDD90\uDD95\uDD96\uDDA4\uDDA5\uDDA8\uDDB1\uDDB2\uDDBC\uDDC2-\uDDC4\uDDD1-\uDDD3\uDDDC-\uDDDE\uDDE1\uDDE3\uDDE8\uDDEF\uDDF3\uDDFA-\uDE4F\uDE80-\uDEC5\uDECB-\uDED2\uDED5\uDEE0-\uDEE5\uDEE9\uDEEB\uDEEC\uDEF0\uDEF3-\uDEFA\uDFE0-\uDFEB]|\uD83E[\uDD0D-\uDD3A\uDD3C-\uDD45\uDD47-\uDD71\uDD73-\uDD76\uDD7A-\uDDA2\uDDA5-\uDDAA\uDDAE-\uDDCA\uDDCD-\uDDFF\uDE70-\uDE73\uDE78-\uDE7A\uDE80-\uDE82\uDE90-\uDE95])\uFE0F|(?:[\u261D\u26F9\u270A-\u270D]|\uD83C[\uDF85\uDFC2-\uDFC4\uDFC7\uDFCA-\uDFCC]|\uD83D[\uDC42\uDC43\uDC46-\uDC50\uDC66-\uDC78\uDC7C\uDC81-\uDC83\uDC85-\uDC87\uDC8F\uDC91\uDCAA\uDD74\uDD75\uDD7A\uDD90\uDD95\uDD96\uDE45-\uDE47\uDE4B-\uDE4F\uDEA3\uDEB4-\uDEB6\uDEC0\uDECC]|\uD83E[\uDD0F\uDD18-\uDD1F\uDD26\uDD30-\uDD39\uDD3C-\uDD3E\uDDB5\uDDB6\uDDB8\uDDB9\uDDBB\uDDCD-\uDDCF\uDDD1-\uDDDD])/g;
+};
diff --git a/server/node_modules/emoji-regex/package.json b/server/node_modules/emoji-regex/package.json
new file mode 100644
index 0000000..6d32352
--- /dev/null
+++ b/server/node_modules/emoji-regex/package.json
@@ -0,0 +1,50 @@
+{
+  "name": "emoji-regex",
+  "version": "8.0.0",
+  "description": "A regular expression to match all Emoji-only symbols as per the Unicode Standard.",
+  "homepage": "https://mths.be/emoji-regex",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "keywords": [
+    "unicode",
+    "regex",
+    "regexp",
+    "regular expressions",
+    "code points",
+    "symbols",
+    "characters",
+    "emoji"
+  ],
+  "license": "MIT",
+  "author": {
+    "name": "Mathias Bynens",
+    "url": "https://mathiasbynens.be/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/mathiasbynens/emoji-regex.git"
+  },
+  "bugs": "https://github.com/mathiasbynens/emoji-regex/issues",
+  "files": [
+    "LICENSE-MIT.txt",
+    "index.js",
+    "index.d.ts",
+    "text.js",
+    "es2015/index.js",
+    "es2015/text.js"
+  ],
+  "scripts": {
+    "build": "rm -rf -- es2015; babel src -d .; NODE_ENV=es2015 babel src -d ./es2015; node script/inject-sequences.js",
+    "test": "mocha",
+    "test:watch": "npm run test -- --watch"
+  },
+  "devDependencies": {
+    "@babel/cli": "^7.2.3",
+    "@babel/core": "^7.3.4",
+    "@babel/plugin-proposal-unicode-property-regex": "^7.2.0",
+    "@babel/preset-env": "^7.3.4",
+    "mocha": "^6.0.2",
+    "regexgen": "^1.3.0",
+    "unicode-12.0.0": "^0.7.9"
+  }
+}
diff --git a/server/node_modules/emoji-regex/text.js b/server/node_modules/emoji-regex/text.js
new file mode 100644
index 0000000..0a55ce2
--- /dev/null
+++ b/server/node_modules/emoji-regex/text.js
@@ -0,0 +1,6 @@
+"use strict";
+
+module.exports = function () {
+  // https://mths.be/emoji
+  return /\uD83C\uDFF4\uDB40\uDC67\uDB40\uDC62(?:\uDB40\uDC65\uDB40\uDC6E\uDB40\uDC67|\uDB40\uDC73\uDB40\uDC63\uDB40\uDC74|\uDB40\uDC77\uDB40\uDC6C\uDB40\uDC73)\uDB40\uDC7F|\uD83D\uDC68(?:\uD83C\uDFFC\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68\uD83C\uDFFB|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFF\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB-\uDFFE])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFE\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB-\uDFFD])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFD\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB\uDFFC])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\u200D(?:\u2764\uFE0F\u200D(?:\uD83D\uDC8B\u200D)?\uD83D\uDC68|(?:\uD83D[\uDC68\uDC69])\u200D(?:\uD83D\uDC66\u200D\uD83D\uDC66|\uD83D\uDC67\u200D(?:\uD83D[\uDC66\uDC67]))|\uD83D\uDC66\u200D\uD83D\uDC66|\uD83D\uDC67\u200D(?:\uD83D[\uDC66\uDC67])|(?:\uD83D[\uDC68\uDC69])\u200D(?:\uD83D[\uDC66\uDC67])|[\u2695\u2696\u2708]\uFE0F|\uD83D[\uDC66\uDC67]|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|(?:\uD83C\uDFFB\u200D[\u2695\u2696\u2708]|\uD83C\uDFFF\u200D[\u2695\u2696\u2708]|\uD83C\uDFFE\u200D[\u2695\u2696\u2708]|\uD83C\uDFFD\u200D[\u2695\u2696\u2708]|\uD83C\uDFFC\u200D[\u2695\u2696\u2708])\uFE0F|\uD83C\uDFFB\u200D(?:\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C[\uDFFB-\uDFFF])|(?:\uD83E\uDDD1\uD83C\uDFFB\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1|\uD83D\uDC69\uD83C\uDFFC\u200D\uD83E\uDD1D\u200D\uD83D\uDC69)\uD83C\uDFFB|\uD83E\uDDD1(?:\uD83C\uDFFF\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1(?:\uD83C[\uDFFB-\uDFFF])|\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1)|(?:\uD83E\uDDD1\uD83C\uDFFE\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1|\uD83D\uDC69\uD83C\uDFFF\u200D\uD83E\uDD1D\u200D(?:\uD83D[\uDC68\uDC69]))(?:\uD83C[\uDFFB-\uDFFE])|(?:\uD83E\uDDD1\uD83C\uDFFC\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1|\uD83D\uDC69\uD83C\uDFFD\u200D\uD83E\uDD1D\u200D\uD83D\uDC69)(?:\uD83C[\uDFFB\uDFFC])|\uD83D\uDC69(?:\uD83C\uDFFE\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB-\uDFFD\uDFFF])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFC\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB\uDFFD-\uDFFF])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFB\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFC-\uDFFF])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFD\u200D(?:\uD83E\uDD1D\u200D\uD83D\uDC68(?:\uD83C[\uDFFB\uDFFC\uDFFE\uDFFF])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\u200D(?:\u2764\uFE0F\u200D(?:\uD83D\uDC8B\u200D(?:\uD83D[\uDC68\uDC69])|\uD83D[\uDC68\uDC69])|\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD])|\uD83C\uDFFF\u200D(?:\uD83C[\uDF3E\uDF73\uDF93\uDFA4\uDFA8\uDFEB\uDFED]|\uD83D[\uDCBB\uDCBC\uDD27\uDD2C\uDE80\uDE92]|\uD83E[\uDDAF-\uDDB3\uDDBC\uDDBD]))|\uD83D\uDC69\u200D\uD83D\uDC69\u200D(?:\uD83D\uDC66\u200D\uD83D\uDC66|\uD83D\uDC67\u200D(?:\uD83D[\uDC66\uDC67]))|(?:\uD83E\uDDD1\uD83C\uDFFD\u200D\uD83E\uDD1D\u200D\uD83E\uDDD1|\uD83D\uDC69\uD83C\uDFFE\u200D\uD83E\uDD1D\u200D\uD83D\uDC69)(?:\uD83C[\uDFFB-\uDFFD])|\uD83D\uDC69\u200D\uD83D\uDC66\u200D\uD83D\uDC66|\uD83D\uDC69\u200D\uD83D\uDC69\u200D(?:\uD83D[\uDC66\uDC67])|(?:\uD83D\uDC41\uFE0F\u200D\uD83D\uDDE8|\uD83D\uDC69(?:\uD83C\uDFFF\u200D[\u2695\u2696\u2708]|\uD83C\uDFFE\u200D[\u2695\u2696\u2708]|\uD83C\uDFFC\u200D[\u2695\u2696\u2708]|\uD83C\uDFFB\u200D[\u2695\u2696\u2708]|\uD83C\uDFFD\u200D[\u2695\u2696\u2708]|\u200D[\u2695\u2696\u2708])|(?:(?:\u26F9|\uD83C[\uDFCB\uDFCC]|\uD83D\uDD75)\uFE0F|\uD83D\uDC6F|\uD83E[\uDD3C\uDDDE\uDDDF])\u200D[\u2640\u2642]|(?:\u26F9|\uD83C[\uDFCB\uDFCC]|\uD83D\uDD75)(?:\uD83C[\uDFFB-\uDFFF])\u200D[\u2640\u2642]|(?:\uD83C[\uDFC3\uDFC4\uDFCA]|\uD83D[\uDC6E\uDC71\uDC73\uDC77\uDC81\uDC82\uDC86\uDC87\uDE45-\uDE47\uDE4B\uDE4D\uDE4E\uDEA3\uDEB4-\uDEB6]|\uD83E[\uDD26\uDD37-\uDD39\uDD3D\uDD3E\uDDB8\uDDB9\uDDCD-\uDDCF\uDDD6-\uDDDD])(?:(?:\uD83C[\uDFFB-\uDFFF])\u200D[\u2640\u2642]|\u200D[\u2640\u2642])|\uD83C\uDFF4\u200D\u2620)\uFE0F|\uD83D\uDC69\u200D\uD83D\uDC67\u200D(?:\uD83D[\uDC66\uDC67])|\uD83C\uDFF3\uFE0F\u200D\uD83C\uDF08|\uD83D\uDC15\u200D\uD83E\uDDBA|\uD83D\uDC69\u200D\uD83D\uDC66|\uD83D\uDC69\u200D\uD83D\uDC67|\uD83C\uDDFD\uD83C\uDDF0|\uD83C\uDDF4\uD83C\uDDF2|\uD83C\uDDF6\uD83C\uDDE6|[#\*0-9]\uFE0F\u20E3|\uD83C\uDDE7(?:\uD83C[\uDDE6\uDDE7\uDDE9-\uDDEF\uDDF1-\uDDF4\uDDF6-\uDDF9\uDDFB\uDDFC\uDDFE\uDDFF])|\uD83C\uDDF9(?:\uD83C[\uDDE6\uDDE8\uDDE9\uDDEB-\uDDED\uDDEF-\uDDF4\uDDF7\uDDF9\uDDFB\uDDFC\uDDFF])|\uD83C\uDDEA(?:\uD83C[\uDDE6\uDDE8\uDDEA\uDDEC\uDDED\uDDF7-\uDDFA])|\uD83E\uDDD1(?:\uD83C[\uDFFB-\uDFFF])|\uD83C\uDDF7(?:\uD83C[\uDDEA\uDDF4\uDDF8\uDDFA\uDDFC])|\uD83D\uDC69(?:\uD83C[\uDFFB-\uDFFF])|\uD83C\uDDF2(?:\uD83C[\uDDE6\uDDE8-\uDDED\uDDF0-\uDDFF])|\uD83C\uDDE6(?:\uD83C[\uDDE8-\uDDEC\uDDEE\uDDF1\uDDF2\uDDF4\uDDF6-\uDDFA\uDDFC\uDDFD\uDDFF])|\uD83C\uDDF0(?:\uD83C[\uDDEA\uDDEC-\uDDEE\uDDF2\uDDF3\uDDF5\uDDF7\uDDFC\uDDFE\uDDFF])|\uD83C\uDDED(?:\uD83C[\uDDF0\uDDF2\uDDF3\uDDF7\uDDF9\uDDFA])|\uD83C\uDDE9(?:\uD83C[\uDDEA\uDDEC\uDDEF\uDDF0\uDDF2\uDDF4\uDDFF])|\uD83C\uDDFE(?:\uD83C[\uDDEA\uDDF9])|\uD83C\uDDEC(?:\uD83C[\uDDE6\uDDE7\uDDE9-\uDDEE\uDDF1-\uDDF3\uDDF5-\uDDFA\uDDFC\uDDFE])|\uD83C\uDDF8(?:\uD83C[\uDDE6-\uDDEA\uDDEC-\uDDF4\uDDF7-\uDDF9\uDDFB\uDDFD-\uDDFF])|\uD83C\uDDEB(?:\uD83C[\uDDEE-\uDDF0\uDDF2\uDDF4\uDDF7])|\uD83C\uDDF5(?:\uD83C[\uDDE6\uDDEA-\uDDED\uDDF0-\uDDF3\uDDF7-\uDDF9\uDDFC\uDDFE])|\uD83C\uDDFB(?:\uD83C[\uDDE6\uDDE8\uDDEA\uDDEC\uDDEE\uDDF3\uDDFA])|\uD83C\uDDF3(?:\uD83C[\uDDE6\uDDE8\uDDEA-\uDDEC\uDDEE\uDDF1\uDDF4\uDDF5\uDDF7\uDDFA\uDDFF])|\uD83C\uDDE8(?:\uD83C[\uDDE6\uDDE8\uDDE9\uDDEB-\uDDEE\uDDF0-\uDDF5\uDDF7\uDDFA-\uDDFF])|\uD83C\uDDF1(?:\uD83C[\uDDE6-\uDDE8\uDDEE\uDDF0\uDDF7-\uDDFB\uDDFE])|\uD83C\uDDFF(?:\uD83C[\uDDE6\uDDF2\uDDFC])|\uD83C\uDDFC(?:\uD83C[\uDDEB\uDDF8])|\uD83C\uDDFA(?:\uD83C[\uDDE6\uDDEC\uDDF2\uDDF3\uDDF8\uDDFE\uDDFF])|\uD83C\uDDEE(?:\uD83C[\uDDE8-\uDDEA\uDDF1-\uDDF4\uDDF6-\uDDF9])|\uD83C\uDDEF(?:\uD83C[\uDDEA\uDDF2\uDDF4\uDDF5])|(?:\uD83C[\uDFC3\uDFC4\uDFCA]|\uD83D[\uDC6E\uDC71\uDC73\uDC77\uDC81\uDC82\uDC86\uDC87\uDE45-\uDE47\uDE4B\uDE4D\uDE4E\uDEA3\uDEB4-\uDEB6]|\uD83E[\uDD26\uDD37-\uDD39\uDD3D\uDD3E\uDDB8\uDDB9\uDDCD-\uDDCF\uDDD6-\uDDDD])(?:\uD83C[\uDFFB-\uDFFF])|(?:\u26F9|\uD83C[\uDFCB\uDFCC]|\uD83D\uDD75)(?:\uD83C[\uDFFB-\uDFFF])|(?:[\u261D\u270A-\u270D]|\uD83C[\uDF85\uDFC2\uDFC7]|\uD83D[\uDC42\uDC43\uDC46-\uDC50\uDC66\uDC67\uDC6B-\uDC6D\uDC70\uDC72\uDC74-\uDC76\uDC78\uDC7C\uDC83\uDC85\uDCAA\uDD74\uDD7A\uDD90\uDD95\uDD96\uDE4C\uDE4F\uDEC0\uDECC]|\uD83E[\uDD0F\uDD18-\uDD1C\uDD1E\uDD1F\uDD30-\uDD36\uDDB5\uDDB6\uDDBB\uDDD2-\uDDD5])(?:\uD83C[\uDFFB-\uDFFF])|(?:[\u231A\u231B\u23E9-\u23EC\u23F0\u23F3\u25FD\u25FE\u2614\u2615\u2648-\u2653\u267F\u2693\u26A1\u26AA\u26AB\u26BD\u26BE\u26C4\u26C5\u26CE\u26D4\u26EA\u26F2\u26F3\u26F5\u26FA\u26FD\u2705\u270A\u270B\u2728\u274C\u274E\u2753-\u2755\u2757\u2795-\u2797\u27B0\u27BF\u2B1B\u2B1C\u2B50\u2B55]|\uD83C[\uDC04\uDCCF\uDD8E\uDD91-\uDD9A\uDDE6-\uDDFF\uDE01\uDE1A\uDE2F\uDE32-\uDE36\uDE38-\uDE3A\uDE50\uDE51\uDF00-\uDF20\uDF2D-\uDF35\uDF37-\uDF7C\uDF7E-\uDF93\uDFA0-\uDFCA\uDFCF-\uDFD3\uDFE0-\uDFF0\uDFF4\uDFF8-\uDFFF]|\uD83D[\uDC00-\uDC3E\uDC40\uDC42-\uDCFC\uDCFF-\uDD3D\uDD4B-\uDD4E\uDD50-\uDD67\uDD7A\uDD95\uDD96\uDDA4\uDDFB-\uDE4F\uDE80-\uDEC5\uDECC\uDED0-\uDED2\uDED5\uDEEB\uDEEC\uDEF4-\uDEFA\uDFE0-\uDFEB]|\uD83E[\uDD0D-\uDD3A\uDD3C-\uDD45\uDD47-\uDD71\uDD73-\uDD76\uDD7A-\uDDA2\uDDA5-\uDDAA\uDDAE-\uDDCA\uDDCD-\uDDFF\uDE70-\uDE73\uDE78-\uDE7A\uDE80-\uDE82\uDE90-\uDE95])|(?:[#\*0-9\xA9\xAE\u203C\u2049\u2122\u2139\u2194-\u2199\u21A9\u21AA\u231A\u231B\u2328\u23CF\u23E9-\u23F3\u23F8-\u23FA\u24C2\u25AA\u25AB\u25B6\u25C0\u25FB-\u25FE\u2600-\u2604\u260E\u2611\u2614\u2615\u2618\u261D\u2620\u2622\u2623\u2626\u262A\u262E\u262F\u2638-\u263A\u2640\u2642\u2648-\u2653\u265F\u2660\u2663\u2665\u2666\u2668\u267B\u267E\u267F\u2692-\u2697\u2699\u269B\u269C\u26A0\u26A1\u26AA\u26AB\u26B0\u26B1\u26BD\u26BE\u26C4\u26C5\u26C8\u26CE\u26CF\u26D1\u26D3\u26D4\u26E9\u26EA\u26F0-\u26F5\u26F7-\u26FA\u26FD\u2702\u2705\u2708-\u270D\u270F\u2712\u2714\u2716\u271D\u2721\u2728\u2733\u2734\u2744\u2747\u274C\u274E\u2753-\u2755\u2757\u2763\u2764\u2795-\u2797\u27A1\u27B0\u27BF\u2934\u2935\u2B05-\u2B07\u2B1B\u2B1C\u2B50\u2B55\u3030\u303D\u3297\u3299]|\uD83C[\uDC04\uDCCF\uDD70\uDD71\uDD7E\uDD7F\uDD8E\uDD91-\uDD9A\uDDE6-\uDDFF\uDE01\uDE02\uDE1A\uDE2F\uDE32-\uDE3A\uDE50\uDE51\uDF00-\uDF21\uDF24-\uDF93\uDF96\uDF97\uDF99-\uDF9B\uDF9E-\uDFF0\uDFF3-\uDFF5\uDFF7-\uDFFF]|\uD83D[\uDC00-\uDCFD\uDCFF-\uDD3D\uDD49-\uDD4E\uDD50-\uDD67\uDD6F\uDD70\uDD73-\uDD7A\uDD87\uDD8A-\uDD8D\uDD90\uDD95\uDD96\uDDA4\uDDA5\uDDA8\uDDB1\uDDB2\uDDBC\uDDC2-\uDDC4\uDDD1-\uDDD3\uDDDC-\uDDDE\uDDE1\uDDE3\uDDE8\uDDEF\uDDF3\uDDFA-\uDE4F\uDE80-\uDEC5\uDECB-\uDED2\uDED5\uDEE0-\uDEE5\uDEE9\uDEEB\uDEEC\uDEF0\uDEF3-\uDEFA\uDFE0-\uDFEB]|\uD83E[\uDD0D-\uDD3A\uDD3C-\uDD45\uDD47-\uDD71\uDD73-\uDD76\uDD7A-\uDDA2\uDDA5-\uDDAA\uDDAE-\uDDCA\uDDCD-\uDDFF\uDE70-\uDE73\uDE78-\uDE7A\uDE80-\uDE82\uDE90-\uDE95])\uFE0F?|(?:[\u261D\u26F9\u270A-\u270D]|\uD83C[\uDF85\uDFC2-\uDFC4\uDFC7\uDFCA-\uDFCC]|\uD83D[\uDC42\uDC43\uDC46-\uDC50\uDC66-\uDC78\uDC7C\uDC81-\uDC83\uDC85-\uDC87\uDC8F\uDC91\uDCAA\uDD74\uDD75\uDD7A\uDD90\uDD95\uDD96\uDE45-\uDE47\uDE4B-\uDE4F\uDEA3\uDEB4-\uDEB6\uDEC0\uDECC]|\uD83E[\uDD0F\uDD18-\uDD1F\uDD26\uDD30-\uDD39\uDD3C-\uDD3E\uDDB5\uDDB6\uDDB8\uDDB9\uDDBB\uDDCD-\uDDCF\uDDD1-\uDDDD])/g;
+};
diff --git a/server/node_modules/encodeurl/LICENSE b/server/node_modules/encodeurl/LICENSE
new file mode 100644
index 0000000..8812229
--- /dev/null
+++ b/server/node_modules/encodeurl/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2016 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/encodeurl/README.md b/server/node_modules/encodeurl/README.md
new file mode 100644
index 0000000..3842493
--- /dev/null
+++ b/server/node_modules/encodeurl/README.md
@@ -0,0 +1,109 @@
+# Encode URL
+
+Encode a URL to a percent-encoded form, excluding already-encoded sequences.
+
+## Installation
+
+```sh
+npm install encodeurl
+```
+
+## API
+
+```js
+var encodeUrl = require('encodeurl')
+```
+
+### encodeUrl(url)
+
+Encode a URL to a percent-encoded form, excluding already-encoded sequences.
+
+This function accepts a URL and encodes all the non-URL code points (as UTF-8 byte sequences). It will not encode the "%" character unless it is not part of a valid sequence (`%20` will be left as-is, but `%foo` will be encoded as `%25foo`).
+
+This encode is meant to be "safe" and does not throw errors. It will try as hard as it can to properly encode the given URL, including replacing any raw, unpaired surrogate pairs with the Unicode replacement character prior to encoding.
+
+## Examples
+
+### Encode a URL containing user-controlled data
+
+```js
+var encodeUrl = require('encodeurl')
+var escapeHtml = require('escape-html')
+
+http.createServer(function onRequest (req, res) {
+  // get encoded form of inbound url
+  var url = encodeUrl(req.url)
+
+  // create html message
+  var body = '<p>Location ' + escapeHtml(url) + ' not found</p>'
+
+  // send a 404
+  res.statusCode = 404
+  res.setHeader('Content-Type', 'text/html; charset=UTF-8')
+  res.setHeader('Content-Length', String(Buffer.byteLength(body, 'utf-8')))
+  res.end(body, 'utf-8')
+})
+```
+
+### Encode a URL for use in a header field
+
+```js
+var encodeUrl = require('encodeurl')
+var escapeHtml = require('escape-html')
+var url = require('url')
+
+http.createServer(function onRequest (req, res) {
+  // parse inbound url
+  var href = url.parse(req)
+
+  // set new host for redirect
+  href.host = 'localhost'
+  href.protocol = 'https:'
+  href.slashes = true
+
+  // create location header
+  var location = encodeUrl(url.format(href))
+
+  // create html message
+  var body = '<p>Redirecting to new site: ' + escapeHtml(location) + '</p>'
+
+  // send a 301
+  res.statusCode = 301
+  res.setHeader('Content-Type', 'text/html; charset=UTF-8')
+  res.setHeader('Content-Length', String(Buffer.byteLength(body, 'utf-8')))
+  res.setHeader('Location', location)
+  res.end(body, 'utf-8')
+})
+```
+
+## Similarities
+
+This function is _similar_ to the intrinsic function `encodeURI`. However, it will not encode:
+
+* The `\`, `^`, or `|` characters
+* The `%` character when it's part of a valid sequence
+* `[` and `]` (for IPv6 hostnames)
+* Replaces raw, unpaired surrogate pairs with the Unicode replacement character
+
+As a result, the encoding aligns closely with the behavior in the [WHATWG URL specification][whatwg-url]. However, this package only encodes strings and does not do any URL parsing or formatting.
+
+It is expected that any output from `new URL(url)` will not change when used with this package, as the output has already been encoded. Additionally, if we were to encode before `new URL(url)`, we do not expect the before and after encoded formats to be parsed any differently.
+
+## Testing
+
+```sh
+$ npm test
+$ npm run lint
+```
+
+## References
+
+- [RFC 3986: Uniform Resource Identifier (URI): Generic Syntax][rfc-3986]
+- [WHATWG URL Living Standard][whatwg-url]
+
+[rfc-3986]: https://tools.ietf.org/html/rfc3986
+[whatwg-url]: https://url.spec.whatwg.org/
+
+## License
+
+[MIT](LICENSE)
diff --git a/server/node_modules/encodeurl/index.js b/server/node_modules/encodeurl/index.js
new file mode 100644
index 0000000..a49ee5a
--- /dev/null
+++ b/server/node_modules/encodeurl/index.js
@@ -0,0 +1,60 @@
+/*!
+ * encodeurl
+ * Copyright(c) 2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = encodeUrl
+
+/**
+ * RegExp to match non-URL code points, *after* encoding (i.e. not including "%")
+ * and including invalid escape sequences.
+ * @private
+ */
+
+var ENCODE_CHARS_REGEXP = /(?:[^\x21\x23-\x3B\x3D\x3F-\x5F\x61-\x7A\x7C\x7E]|%(?:[^0-9A-Fa-f]|[0-9A-Fa-f][^0-9A-Fa-f]|$))+/g
+
+/**
+ * RegExp to match unmatched surrogate pair.
+ * @private
+ */
+
+var UNMATCHED_SURROGATE_PAIR_REGEXP = /(^|[^\uD800-\uDBFF])[\uDC00-\uDFFF]|[\uD800-\uDBFF]([^\uDC00-\uDFFF]|$)/g
+
+/**
+ * String to replace unmatched surrogate pair with.
+ * @private
+ */
+
+var UNMATCHED_SURROGATE_PAIR_REPLACE = '$1\uFFFD$2'
+
+/**
+ * Encode a URL to a percent-encoded form, excluding already-encoded sequences.
+ *
+ * This function will take an already-encoded URL and encode all the non-URL
+ * code points. This function will not encode the "%" character unless it is
+ * not part of a valid sequence (`%20` will be left as-is, but `%foo` will
+ * be encoded as `%25foo`).
+ *
+ * This encode is meant to be "safe" and does not throw errors. It will try as
+ * hard as it can to properly encode the given URL, including replacing any raw,
+ * unpaired surrogate pairs with the Unicode replacement character prior to
+ * encoding.
+ *
+ * @param {string} url
+ * @return {string}
+ * @public
+ */
+
+function encodeUrl (url) {
+  return String(url)
+    .replace(UNMATCHED_SURROGATE_PAIR_REGEXP, UNMATCHED_SURROGATE_PAIR_REPLACE)
+    .replace(ENCODE_CHARS_REGEXP, encodeURI)
+}
diff --git a/server/node_modules/encodeurl/package.json b/server/node_modules/encodeurl/package.json
new file mode 100644
index 0000000..3133822
--- /dev/null
+++ b/server/node_modules/encodeurl/package.json
@@ -0,0 +1,40 @@
+{
+  "name": "encodeurl",
+  "description": "Encode a URL to a percent-encoded form, excluding already-encoded sequences",
+  "version": "2.0.0",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "encode",
+    "encodeurl",
+    "url"
+  ],
+  "repository": "pillarjs/encodeurl",
+  "devDependencies": {
+    "eslint": "5.11.1",
+    "eslint-config-standard": "12.0.0",
+    "eslint-plugin-import": "2.14.0",
+    "eslint-plugin-node": "7.0.1",
+    "eslint-plugin-promise": "4.0.1",
+    "eslint-plugin-standard": "4.0.0",
+    "istanbul": "0.4.5",
+    "mocha": "2.5.3"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  }
+}
diff --git a/server/node_modules/encoding/.prettierrc.js b/server/node_modules/encoding/.prettierrc.js
new file mode 100644
index 0000000..3f83654
--- /dev/null
+++ b/server/node_modules/encoding/.prettierrc.js
@@ -0,0 +1,8 @@
+module.exports = {
+    printWidth: 160,
+    tabWidth: 4,
+    singleQuote: true,
+    endOfLine: 'lf',
+    trailingComma: 'none',
+    arrowParens: 'avoid'
+};
diff --git a/server/node_modules/encoding/.travis.yml b/server/node_modules/encoding/.travis.yml
new file mode 100644
index 0000000..abc4f48
--- /dev/null
+++ b/server/node_modules/encoding/.travis.yml
@@ -0,0 +1,25 @@
+language: node_js
+sudo: false
+node_js:
+  - "0.10"
+  - 0.12
+  - iojs
+  - 4
+  - 5
+env:
+  - CXX=g++-4.8
+addons:
+  apt:
+    sources:
+      - ubuntu-toolchain-r-test
+    packages:
+      - g++-4.8
+notifications:
+  email:
+    - andris@kreata.ee
+  webhooks:
+    urls:
+      - https://webhooks.gitter.im/e/0ed18fd9b3e529b3c2cc
+    on_success: change  # options: [always|never|change] default: always
+    on_failure: always  # options: [always|never|change] default: always
+    on_start: false     # default: false
diff --git a/server/node_modules/encoding/LICENSE b/server/node_modules/encoding/LICENSE
new file mode 100644
index 0000000..33f5a9a
--- /dev/null
+++ b/server/node_modules/encoding/LICENSE
@@ -0,0 +1,16 @@
+Copyright (c) 2012-2014 Andris Reinman
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/encoding/README.md b/server/node_modules/encoding/README.md
new file mode 100644
index 0000000..6188918
--- /dev/null
+++ b/server/node_modules/encoding/README.md
@@ -0,0 +1,41 @@
+# Encoding
+
+**encoding** is a simple wrapper around [iconv-lite](https://github.com/ashtuchkin/iconv-lite/) to convert strings from one encoding to another.
+
+[![Build Status](https://secure.travis-ci.org/andris9/encoding.svg)](http://travis-ci.org/andris9/Nodemailer)
+[![npm version](https://badge.fury.io/js/encoding.svg)](http://badge.fury.io/js/encoding)
+
+Initially _encoding_ was a wrapper around _node-iconv_ (main) and _iconv-lite_ (fallback) and was used as the encoding layer for Nodemailer/mailparser. Somehow it also ended up as a dependency for a bunch of other project, none of these actually using _node-iconv_. The loading mechanics caused issues for front-end projects and Nodemailer/malparser had moved on, so _node-iconv_ was removed.
+
+## Install
+
+Install through npm
+
+    npm install encoding
+
+## Usage
+
+Require the module
+
+    var encoding = require("encoding");
+
+Convert with encoding.convert()
+
+    var resultBuffer = encoding.convert(text, toCharset, fromCharset);
+
+Where
+
+-   **text** is either a Buffer or a String to be converted
+-   **toCharset** is the characterset to convert the string
+-   **fromCharset** (_optional_, defaults to UTF-8) is the source charset
+
+Output of the conversion is always a Buffer object.
+
+Example
+
+    var result = encoding.convert("ÕÄÖÜ", "Latin_1");
+    console.log(result); //<Buffer d5 c4 d6 dc>
+
+## License
+
+**MIT**
diff --git a/server/node_modules/encoding/lib/encoding.js b/server/node_modules/encoding/lib/encoding.js
new file mode 100644
index 0000000..865c24b
--- /dev/null
+++ b/server/node_modules/encoding/lib/encoding.js
@@ -0,0 +1,83 @@
+'use strict';
+
+var iconvLite = require('iconv-lite');
+
+// Expose to the world
+module.exports.convert = convert;
+
+/**
+ * Convert encoding of an UTF-8 string or a buffer
+ *
+ * @param {String|Buffer} str String to be converted
+ * @param {String} to Encoding to be converted to
+ * @param {String} [from='UTF-8'] Encoding to be converted from
+ * @return {Buffer} Encoded string
+ */
+function convert(str, to, from) {
+    from = checkEncoding(from || 'UTF-8');
+    to = checkEncoding(to || 'UTF-8');
+    str = str || '';
+
+    var result;
+
+    if (from !== 'UTF-8' && typeof str === 'string') {
+        str = Buffer.from(str, 'binary');
+    }
+
+    if (from === to) {
+        if (typeof str === 'string') {
+            result = Buffer.from(str);
+        } else {
+            result = str;
+        }
+    } else {
+        try {
+            result = convertIconvLite(str, to, from);
+        } catch (E) {
+            console.error(E);
+            result = str;
+        }
+    }
+
+    if (typeof result === 'string') {
+        result = Buffer.from(result, 'utf-8');
+    }
+
+    return result;
+}
+
+/**
+ * Convert encoding of astring with iconv-lite
+ *
+ * @param {String|Buffer} str String to be converted
+ * @param {String} to Encoding to be converted to
+ * @param {String} [from='UTF-8'] Encoding to be converted from
+ * @return {Buffer} Encoded string
+ */
+function convertIconvLite(str, to, from) {
+    if (to === 'UTF-8') {
+        return iconvLite.decode(str, from);
+    } else if (from === 'UTF-8') {
+        return iconvLite.encode(str, to);
+    } else {
+        return iconvLite.encode(iconvLite.decode(str, from), to);
+    }
+}
+
+/**
+ * Converts charset name if needed
+ *
+ * @param {String} name Character set
+ * @return {String} Character set name
+ */
+function checkEncoding(name) {
+    return (name || '')
+        .toString()
+        .trim()
+        .replace(/^latin[\-_]?(\d+)$/i, 'ISO-8859-$1')
+        .replace(/^win(?:dows)?[\-_]?(\d+)$/i, 'WINDOWS-$1')
+        .replace(/^utf[\-_]?(\d+)$/i, 'UTF-$1')
+        .replace(/^ks_c_5601\-1987$/i, 'CP949')
+        .replace(/^us[\-_]?ascii$/i, 'ASCII')
+        .toUpperCase();
+}
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/.github/dependabot.yml b/server/node_modules/encoding/node_modules/iconv-lite/.github/dependabot.yml
new file mode 100644
index 0000000..e4a0e0a
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/.github/dependabot.yml
@@ -0,0 +1,11 @@
+# Please see the documentation for all configuration options:
+# https://help.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    allow:
+      - dependency-type: production
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/.idea/codeStyles/Project.xml b/server/node_modules/encoding/node_modules/iconv-lite/.idea/codeStyles/Project.xml
new file mode 100644
index 0000000..3f2688c
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/.idea/codeStyles/Project.xml
@@ -0,0 +1,47 @@
+<component name="ProjectCodeStyleConfiguration">
+  <code_scheme name="Project" version="173">
+    <HTMLCodeStyleSettings>
+      <option name="HTML_SPACE_INSIDE_EMPTY_TAG" value="true" />
+      <option name="HTML_ENFORCE_QUOTES" value="true" />
+    </HTMLCodeStyleSettings>
+    <JSCodeStyleSettings version="0">
+      <option name="FORCE_SEMICOLON_STYLE" value="true" />
+      <option name="SPACE_BEFORE_FUNCTION_LEFT_PARENTH" value="false" />
+      <option name="FORCE_QUOTE_STYlE" value="true" />
+      <option name="ENFORCE_TRAILING_COMMA" value="Remove" />
+      <option name="SPACES_WITHIN_OBJECT_LITERAL_BRACES" value="true" />
+      <option name="SPACES_WITHIN_IMPORTS" value="true" />
+    </JSCodeStyleSettings>
+    <TypeScriptCodeStyleSettings version="0">
+      <option name="FORCE_SEMICOLON_STYLE" value="true" />
+      <option name="SPACE_BEFORE_FUNCTION_LEFT_PARENTH" value="false" />
+      <option name="FORCE_QUOTE_STYlE" value="true" />
+      <option name="ENFORCE_TRAILING_COMMA" value="Remove" />
+      <option name="SPACES_WITHIN_OBJECT_LITERAL_BRACES" value="true" />
+      <option name="SPACES_WITHIN_IMPORTS" value="true" />
+    </TypeScriptCodeStyleSettings>
+    <VueCodeStyleSettings>
+      <option name="INTERPOLATION_NEW_LINE_AFTER_START_DELIMITER" value="false" />
+      <option name="INTERPOLATION_NEW_LINE_BEFORE_END_DELIMITER" value="false" />
+    </VueCodeStyleSettings>
+    <codeStyleSettings language="HTML">
+      <option name="SOFT_MARGINS" value="100" />
+      <indentOptions>
+        <option name="CONTINUATION_INDENT_SIZE" value="4" />
+      </indentOptions>
+    </codeStyleSettings>
+    <codeStyleSettings language="JavaScript">
+      <option name="SOFT_MARGINS" value="100" />
+    </codeStyleSettings>
+    <codeStyleSettings language="TypeScript">
+      <option name="SOFT_MARGINS" value="100" />
+    </codeStyleSettings>
+    <codeStyleSettings language="Vue">
+      <option name="SOFT_MARGINS" value="100" />
+      <indentOptions>
+        <option name="INDENT_SIZE" value="4" />
+        <option name="TAB_SIZE" value="4" />
+      </indentOptions>
+    </codeStyleSettings>
+  </code_scheme>
+</component>
\ No newline at end of file
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/.idea/codeStyles/codeStyleConfig.xml b/server/node_modules/encoding/node_modules/iconv-lite/.idea/codeStyles/codeStyleConfig.xml
new file mode 100644
index 0000000..79ee123
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/.idea/codeStyles/codeStyleConfig.xml
@@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="USE_PER_PROJECT_SETTINGS" value="true" />
+  </state>
+</component>
\ No newline at end of file
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/.idea/iconv-lite.iml b/server/node_modules/encoding/node_modules/iconv-lite/.idea/iconv-lite.iml
new file mode 100644
index 0000000..0c8867d
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/.idea/iconv-lite.iml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$">
+      <excludeFolder url="file://$MODULE_DIR$/temp" />
+      <excludeFolder url="file://$MODULE_DIR$/.tmp" />
+      <excludeFolder url="file://$MODULE_DIR$/tmp" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
\ No newline at end of file
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/.idea/inspectionProfiles/Project_Default.xml b/server/node_modules/encoding/node_modules/iconv-lite/.idea/inspectionProfiles/Project_Default.xml
new file mode 100644
index 0000000..03d9549
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/.idea/inspectionProfiles/Project_Default.xml
@@ -0,0 +1,6 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="Eslint" enabled="true" level="WARNING" enabled_by_default="true" />
+  </profile>
+</component>
\ No newline at end of file
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/.idea/modules.xml b/server/node_modules/encoding/node_modules/iconv-lite/.idea/modules.xml
new file mode 100644
index 0000000..5d24f2e
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/.idea/modules.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/iconv-lite.iml" filepath="$PROJECT_DIR$/.idea/iconv-lite.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/.idea/vcs.xml b/server/node_modules/encoding/node_modules/iconv-lite/.idea/vcs.xml
new file mode 100644
index 0000000..94a25f7
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/Changelog.md b/server/node_modules/encoding/node_modules/iconv-lite/Changelog.md
new file mode 100644
index 0000000..464549b
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/Changelog.md
@@ -0,0 +1,212 @@
+## 0.6.3 / 2021-05-23
+  * Fix HKSCS encoding to prefer Big5 codes if both Big5 and HKSCS codes are possible (#264)
+
+
+## 0.6.2 / 2020-07-08
+  * Support Uint8Array-s decoding without conversion to Buffers, plus fix an edge case.
+
+
+## 0.6.1 / 2020-06-28
+  * Support Uint8Array-s directly when decoding (#246, by @gyzerok)
+  * Unify package.json version ranges to be strictly semver-compatible (#241)
+  * Fix minor issue in UTF-32 decoder's endianness detection code.
+
+
+## 0.6.0 / 2020-06-08
+  * Updated 'gb18030' encoding to :2005 edition (see https://github.com/whatwg/encoding/issues/22).
+  * Removed `iconv.extendNodeEncodings()` mechanism. It was deprecated 5 years ago and didn't work 
+    in recent Node versions.
+  * Reworked Streaming API behavior in browser environments to fix #204. Streaming API will be 
+    excluded by default in browser packs, saving ~100Kb bundle size, unless enabled explicitly using 
+    `iconv.enableStreamingAPI(require('stream'))`.
+  * Updates to development environment & tests:
+    * Added ./test/webpack private package to test complex new use cases that need custom environment. 
+      It's tested as a separate job in Travis CI.
+    * Updated generation code for the new EUC-KR index file format from Encoding Standard.
+    * Removed Buffer() constructor in tests (#197 by @gabrielschulhof).
+
+
+## 0.5.2 / 2020-06-08
+  * Added `iconv.getEncoder()` and `iconv.getDecoder()` methods to typescript definitions (#229).
+  * Fixed semver version to 6.1.2 to support Node 8.x (by @tanandara).
+  * Capped iconv version to 2.x as 3.x has dropped support for older Node versions.
+  * Switched from instanbul to c8 for code coverage.
+
+
+## 0.5.1 / 2020-01-18
+
+  * Added cp720 encoding (#221, by @kr-deps)
+  * (minor) Changed Changelog.md formatting to use h2. 
+
+
+## 0.5.0 / 2019-06-26
+
+  * Added UTF-32 encoding, both little-endian and big-endian variants (UTF-32LE, UTF32-BE). If endianness
+    is not provided for decoding, it's deduced automatically from the stream using a heuristic similar to
+    what we use in UTF-16. (great work in #216 by @kshetline)
+  * Several minor updates to README (#217 by @oldj, plus some more)
+  * Added Node versions 10 and 12 to Travis test harness.
+
+
+## 0.4.24 / 2018-08-22
+
+  * Added MIK encoding (#196, by @Ivan-Kalatchev)
+
+
+## 0.4.23 / 2018-05-07
+
+  * Fix deprecation warning in Node v10 due to the last usage of `new Buffer` (#185, by @felixbuenemann)
+  * Switched from NodeBuffer to Buffer in typings (#155 by @felixfbecker, #186 by @larssn)
+
+
+## 0.4.22 / 2018-05-05
+
+  * Use older semver style for dependencies to be compatible with Node version 0.10 (#182, by @dougwilson)
+  * Fix tests to accomodate fixes in Node v10 (#182, by @dougwilson)
+
+
+## 0.4.21 / 2018-04-06
+
+  * Fix encoding canonicalization (#156)
+  * Fix the paths in the "browser" field in package.json (#174 by @LMLB)
+  * Removed "contributors" section in package.json - see Git history instead.
+
+
+## 0.4.20 / 2018-04-06
+
+  * Updated `new Buffer()` usages with recommended replacements as it's being deprecated in Node v10 (#176, #178 by @ChALkeR)
+
+
+## 0.4.19 / 2017-09-09
+
+  * Fixed iso8859-1 codec regression in handling untranslatable characters (#162, caused by #147)
+  * Re-generated windows1255 codec, because it was updated in iconv project
+  * Fixed grammar in error message when iconv-lite is loaded with encoding other than utf8
+
+
+## 0.4.18 / 2017-06-13
+
+  * Fixed CESU-8 regression in Node v8.
+
+
+## 0.4.17 / 2017-04-22
+
+ * Updated typescript definition file to support Angular 2 AoT mode (#153 by @larssn)
+
+
+## 0.4.16 / 2017-04-22
+
+ * Added support for React Native (#150)
+ * Changed iso8859-1 encoding to usine internal 'binary' encoding, as it's the same thing (#147 by @mscdex)
+ * Fixed typo in Readme (#138 by @jiangzhuo)
+ * Fixed build for Node v6.10+ by making correct version comparison
+ * Added a warning if iconv-lite is loaded not as utf-8 (see #142)
+
+
+## 0.4.15 / 2016-11-21
+
+ * Fixed typescript type definition (#137)
+
+
+## 0.4.14 / 2016-11-20
+
+ * Preparation for v1.0
+ * Added Node v6 and latest Node versions to Travis CI test rig
+ * Deprecated Node v0.8 support
+ * Typescript typings (@larssn)
+ * Fix encoding of Euro character in GB 18030 (inspired by @lygstate)
+ * Add ms prefix to dbcs windows encodings (@rokoroku)
+
+
+## 0.4.13 / 2015-10-01
+
+ * Fix silly mistake in deprecation notice.
+
+
+## 0.4.12 / 2015-09-26
+
+ * Node v4 support:
+   * Added CESU-8 decoding (#106)
+   * Added deprecation notice for `extendNodeEncodings`
+   * Added Travis tests for Node v4 and io.js latest (#105 by @Mithgol)
+
+
+## 0.4.11 / 2015-07-03
+
+ * Added CESU-8 encoding.
+
+
+## 0.4.10 / 2015-05-26
+
+ * Changed UTF-16 endianness heuristic to take into account any ASCII chars, not
+   just spaces. This should minimize the importance of "default" endianness.
+
+
+## 0.4.9 / 2015-05-24
+
+ * Streamlined BOM handling: strip BOM by default, add BOM when encoding if 
+   addBOM: true. Added docs to Readme.
+ * UTF16 now uses UTF16-LE by default.
+ * Fixed minor issue with big5 encoding.
+ * Added io.js testing on Travis; updated node-iconv version to test against.
+   Now we just skip testing SBCS encodings that node-iconv doesn't support.
+ * (internal refactoring) Updated codec interface to use classes.
+ * Use strict mode in all files.
+
+
+## 0.4.8 / 2015-04-14
+ 
+ * added alias UNICODE-1-1-UTF-7 for UTF-7 encoding (#94)
+
+
+## 0.4.7 / 2015-02-05
+
+ * stop official support of Node.js v0.8. Should still work, but no guarantees.
+   reason: Packages needed for testing are hard to get on Travis CI.
+ * work in environment where Object.prototype is monkey patched with enumerable 
+   props (#89).
+
+
+## 0.4.6 / 2015-01-12
+ 
+ * fix rare aliases of single-byte encodings (thanks @mscdex)
+ * double the timeout for dbcs tests to make them less flaky on travis
+
+
+## 0.4.5 / 2014-11-20
+
+ * fix windows-31j and x-sjis encoding support (@nleush)
+ * minor fix: undefined variable reference when internal error happens
+
+
+## 0.4.4 / 2014-07-16
+
+ * added encodings UTF-7 (RFC2152) and UTF-7-IMAP (RFC3501 Section 5.1.3)
+ * fixed streaming base64 encoding
+
+
+## 0.4.3 / 2014-06-14
+
+ * added encodings UTF-16BE and UTF-16 with BOM
+
+
+## 0.4.2 / 2014-06-12
+
+ * don't throw exception if `extendNodeEncodings()` is called more than once
+
+
+## 0.4.1 / 2014-06-11
+
+ * codepage 808 added
+
+
+## 0.4.0 / 2014-06-10
+
+ * code is rewritten from scratch
+ * all widespread encodings are supported
+ * streaming interface added
+ * browserify compatibility added
+ * (optional) extend core primitive encodings to make usage even simpler
+ * moved from vows to mocha as the testing framework
+
+
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/LICENSE b/server/node_modules/encoding/node_modules/iconv-lite/LICENSE
new file mode 100644
index 0000000..d518d83
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/LICENSE
@@ -0,0 +1,21 @@
+Copyright (c) 2011 Alexander Shtuchkin
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/README.md b/server/node_modules/encoding/node_modules/iconv-lite/README.md
new file mode 100644
index 0000000..3c97f87
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/README.md
@@ -0,0 +1,130 @@
+## iconv-lite: Pure JS character encoding conversion
+
+ * No need for native code compilation. Quick to install, works on Windows and in sandboxed environments like [Cloud9](http://c9.io).
+ * Used in popular projects like [Express.js (body_parser)](https://github.com/expressjs/body-parser), 
+   [Grunt](http://gruntjs.com/), [Nodemailer](http://www.nodemailer.com/), [Yeoman](http://yeoman.io/) and others.
+ * Faster than [node-iconv](https://github.com/bnoordhuis/node-iconv) (see below for performance comparison).
+ * Intuitive encode/decode API, including Streaming support.
+ * In-browser usage via [browserify](https://github.com/substack/node-browserify) or [webpack](https://webpack.js.org/) (~180kb gzip compressed with Buffer shim included).
+ * Typescript [type definition file](https://github.com/ashtuchkin/iconv-lite/blob/master/lib/index.d.ts) included.
+ * React Native is supported (need to install `stream` module to enable Streaming API).
+ * License: MIT.
+
+[![NPM Stats](https://nodei.co/npm/iconv-lite.png)](https://npmjs.org/package/iconv-lite/)  
+[![Build Status](https://travis-ci.org/ashtuchkin/iconv-lite.svg?branch=master)](https://travis-ci.org/ashtuchkin/iconv-lite)
+[![npm](https://img.shields.io/npm/v/iconv-lite.svg)](https://npmjs.org/package/iconv-lite/)
+[![npm downloads](https://img.shields.io/npm/dm/iconv-lite.svg)](https://npmjs.org/package/iconv-lite/)
+[![npm bundle size](https://img.shields.io/bundlephobia/min/iconv-lite.svg)](https://npmjs.org/package/iconv-lite/)
+
+## Usage
+### Basic API
+```javascript
+var iconv = require('iconv-lite');
+
+// Convert from an encoded buffer to a js string.
+str = iconv.decode(Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]), 'win1251');
+
+// Convert from a js string to an encoded buffer.
+buf = iconv.encode("Sample input string", 'win1251');
+
+// Check if encoding is supported
+iconv.encodingExists("us-ascii")
+```
+
+### Streaming API
+```javascript
+
+// Decode stream (from binary data stream to js strings)
+http.createServer(function(req, res) {
+    var converterStream = iconv.decodeStream('win1251');
+    req.pipe(converterStream);
+
+    converterStream.on('data', function(str) {
+        console.log(str); // Do something with decoded strings, chunk-by-chunk.
+    });
+});
+
+// Convert encoding streaming example
+fs.createReadStream('file-in-win1251.txt')
+    .pipe(iconv.decodeStream('win1251'))
+    .pipe(iconv.encodeStream('ucs2'))
+    .pipe(fs.createWriteStream('file-in-ucs2.txt'));
+
+// Sugar: all encode/decode streams have .collect(cb) method to accumulate data.
+http.createServer(function(req, res) {
+    req.pipe(iconv.decodeStream('win1251')).collect(function(err, body) {
+        assert(typeof body == 'string');
+        console.log(body); // full request body string
+    });
+});
+```
+
+## Supported encodings
+
+ *  All node.js native encodings: utf8, ucs2 / utf16-le, ascii, binary, base64, hex.
+ *  Additional unicode encodings: utf16, utf16-be, utf-7, utf-7-imap, utf32, utf32-le, and utf32-be.
+ *  All widespread singlebyte encodings: Windows 125x family, ISO-8859 family, 
+    IBM/DOS codepages, Macintosh family, KOI8 family, all others supported by iconv library. 
+    Aliases like 'latin1', 'us-ascii' also supported.
+ *  All widespread multibyte encodings: CP932, CP936, CP949, CP950, GB2312, GBK, GB18030, Big5, Shift_JIS, EUC-JP.
+
+See [all supported encodings on wiki](https://github.com/ashtuchkin/iconv-lite/wiki/Supported-Encodings).
+
+Most singlebyte encodings are generated automatically from [node-iconv](https://github.com/bnoordhuis/node-iconv). Thank you Ben Noordhuis and libiconv authors!
+
+Multibyte encodings are generated from [Unicode.org mappings](http://www.unicode.org/Public/MAPPINGS/) and [WHATWG Encoding Standard mappings](http://encoding.spec.whatwg.org/). Thank you, respective authors!
+
+
+## Encoding/decoding speed
+
+Comparison with node-iconv module (1000x256kb, on MacBook Pro, Core i5/2.6 GHz, Node v0.12.0). 
+Note: your results may vary, so please always check on your hardware.
+
+    operation             iconv@2.1.4   iconv-lite@0.4.7
+    ----------------------------------------------------------
+    encode('win1251')     ~96 Mb/s      ~320 Mb/s
+    decode('win1251')     ~95 Mb/s      ~246 Mb/s
+
+## BOM handling
+
+ * Decoding: BOM is stripped by default, unless overridden by passing `stripBOM: false` in options
+   (f.ex. `iconv.decode(buf, enc, {stripBOM: false})`).
+   A callback might also be given as a `stripBOM` parameter - it'll be called if BOM character was actually found.
+ * If you want to detect UTF-8 BOM when decoding other encodings, use [node-autodetect-decoder-stream](https://github.com/danielgindi/node-autodetect-decoder-stream) module.
+ * Encoding: No BOM added, unless overridden by `addBOM: true` option.
+
+## UTF-16 Encodings
+
+This library supports UTF-16LE, UTF-16BE and UTF-16 encodings. First two are straightforward, but UTF-16 is trying to be
+smart about endianness in the following ways:
+ * Decoding: uses BOM and 'spaces heuristic' to determine input endianness. Default is UTF-16LE, but can be 
+   overridden with `defaultEncoding: 'utf-16be'` option. Strips BOM unless `stripBOM: false`.
+ * Encoding: uses UTF-16LE and writes BOM by default. Use `addBOM: false` to override.
+
+## UTF-32 Encodings
+
+This library supports UTF-32LE, UTF-32BE and UTF-32 encodings. Like the UTF-16 encoding above, UTF-32 defaults to UTF-32LE, but uses BOM and 'spaces heuristics' to determine input endianness. 
+ * The default of UTF-32LE can be overridden with the `defaultEncoding: 'utf-32be'` option. Strips BOM unless `stripBOM: false`.
+ * Encoding: uses UTF-32LE and writes BOM by default. Use `addBOM: false` to override. (`defaultEncoding: 'utf-32be'` can also be used here to change encoding.)
+
+## Other notes
+
+When decoding, be sure to supply a Buffer to decode() method, otherwise [bad things usually happen](https://github.com/ashtuchkin/iconv-lite/wiki/Use-Buffers-when-decoding).  
+Untranslatable characters are set to � or ?. No transliteration is currently supported.  
+Node versions 0.10.31 and 0.11.13 are buggy, don't use them (see #65, #77).  
+
+## Testing
+
+```bash
+$ git clone git@github.com:ashtuchkin/iconv-lite.git
+$ cd iconv-lite
+$ npm install
+$ npm test
+    
+$ # To view performance:
+$ node test/performance.js
+
+$ # To view test coverage:
+$ npm run coverage
+$ open coverage/lcov-report/index.html
+```
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/dbcs-codec.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/dbcs-codec.js
new file mode 100644
index 0000000..fa83917
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/dbcs-codec.js
@@ -0,0 +1,597 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// Multibyte codec. In this scheme, a character is represented by 1 or more bytes.
+// Our codec supports UTF-16 surrogates, extensions for GB18030 and unicode sequences.
+// To save memory and loading time, we read table files only when requested.
+
+exports._dbcs = DBCSCodec;
+
+var UNASSIGNED = -1,
+    GB18030_CODE = -2,
+    SEQ_START  = -10,
+    NODE_START = -1000,
+    UNASSIGNED_NODE = new Array(0x100),
+    DEF_CHAR = -1;
+
+for (var i = 0; i < 0x100; i++)
+    UNASSIGNED_NODE[i] = UNASSIGNED;
+
+
+// Class DBCSCodec reads and initializes mapping tables.
+function DBCSCodec(codecOptions, iconv) {
+    this.encodingName = codecOptions.encodingName;
+    if (!codecOptions)
+        throw new Error("DBCS codec is called without the data.")
+    if (!codecOptions.table)
+        throw new Error("Encoding '" + this.encodingName + "' has no data.");
+
+    // Load tables.
+    var mappingTable = codecOptions.table();
+
+
+    // Decode tables: MBCS -> Unicode.
+
+    // decodeTables is a trie, encoded as an array of arrays of integers. Internal arrays are trie nodes and all have len = 256.
+    // Trie root is decodeTables[0].
+    // Values: >=  0 -> unicode character code. can be > 0xFFFF
+    //         == UNASSIGNED -> unknown/unassigned sequence.
+    //         == GB18030_CODE -> this is the end of a GB18030 4-byte sequence.
+    //         <= NODE_START -> index of the next node in our trie to process next byte.
+    //         <= SEQ_START  -> index of the start of a character code sequence, in decodeTableSeq.
+    this.decodeTables = [];
+    this.decodeTables[0] = UNASSIGNED_NODE.slice(0); // Create root node.
+
+    // Sometimes a MBCS char corresponds to a sequence of unicode chars. We store them as arrays of integers here. 
+    this.decodeTableSeq = [];
+
+    // Actual mapping tables consist of chunks. Use them to fill up decode tables.
+    for (var i = 0; i < mappingTable.length; i++)
+        this._addDecodeChunk(mappingTable[i]);
+
+    // Load & create GB18030 tables when needed.
+    if (typeof codecOptions.gb18030 === 'function') {
+        this.gb18030 = codecOptions.gb18030(); // Load GB18030 ranges.
+
+        // Add GB18030 common decode nodes.
+        var commonThirdByteNodeIdx = this.decodeTables.length;
+        this.decodeTables.push(UNASSIGNED_NODE.slice(0));
+
+        var commonFourthByteNodeIdx = this.decodeTables.length;
+        this.decodeTables.push(UNASSIGNED_NODE.slice(0));
+
+        // Fill out the tree
+        var firstByteNode = this.decodeTables[0];
+        for (var i = 0x81; i <= 0xFE; i++) {
+            var secondByteNode = this.decodeTables[NODE_START - firstByteNode[i]];
+            for (var j = 0x30; j <= 0x39; j++) {
+                if (secondByteNode[j] === UNASSIGNED) {
+                    secondByteNode[j] = NODE_START - commonThirdByteNodeIdx;
+                } else if (secondByteNode[j] > NODE_START) {
+                    throw new Error("gb18030 decode tables conflict at byte 2");
+                }
+
+                var thirdByteNode = this.decodeTables[NODE_START - secondByteNode[j]];
+                for (var k = 0x81; k <= 0xFE; k++) {
+                    if (thirdByteNode[k] === UNASSIGNED) {
+                        thirdByteNode[k] = NODE_START - commonFourthByteNodeIdx;
+                    } else if (thirdByteNode[k] === NODE_START - commonFourthByteNodeIdx) {
+                        continue;
+                    } else if (thirdByteNode[k] > NODE_START) {
+                        throw new Error("gb18030 decode tables conflict at byte 3");
+                    }
+
+                    var fourthByteNode = this.decodeTables[NODE_START - thirdByteNode[k]];
+                    for (var l = 0x30; l <= 0x39; l++) {
+                        if (fourthByteNode[l] === UNASSIGNED)
+                            fourthByteNode[l] = GB18030_CODE;
+                    }
+                }
+            }
+        }
+    }
+
+    this.defaultCharUnicode = iconv.defaultCharUnicode;
+
+    
+    // Encode tables: Unicode -> DBCS.
+
+    // `encodeTable` is array mapping from unicode char to encoded char. All its values are integers for performance.
+    // Because it can be sparse, it is represented as array of buckets by 256 chars each. Bucket can be null.
+    // Values: >=  0 -> it is a normal char. Write the value (if <=256 then 1 byte, if <=65536 then 2 bytes, etc.).
+    //         == UNASSIGNED -> no conversion found. Output a default char.
+    //         <= SEQ_START  -> it's an index in encodeTableSeq, see below. The character starts a sequence.
+    this.encodeTable = [];
+    
+    // `encodeTableSeq` is used when a sequence of unicode characters is encoded as a single code. We use a tree of
+    // objects where keys correspond to characters in sequence and leafs are the encoded dbcs values. A special DEF_CHAR key
+    // means end of sequence (needed when one sequence is a strict subsequence of another).
+    // Objects are kept separately from encodeTable to increase performance.
+    this.encodeTableSeq = [];
+
+    // Some chars can be decoded, but need not be encoded.
+    var skipEncodeChars = {};
+    if (codecOptions.encodeSkipVals)
+        for (var i = 0; i < codecOptions.encodeSkipVals.length; i++) {
+            var val = codecOptions.encodeSkipVals[i];
+            if (typeof val === 'number')
+                skipEncodeChars[val] = true;
+            else
+                for (var j = val.from; j <= val.to; j++)
+                    skipEncodeChars[j] = true;
+        }
+        
+    // Use decode trie to recursively fill out encode tables.
+    this._fillEncodeTable(0, 0, skipEncodeChars);
+
+    // Add more encoding pairs when needed.
+    if (codecOptions.encodeAdd) {
+        for (var uChar in codecOptions.encodeAdd)
+            if (Object.prototype.hasOwnProperty.call(codecOptions.encodeAdd, uChar))
+                this._setEncodeChar(uChar.charCodeAt(0), codecOptions.encodeAdd[uChar]);
+    }
+
+    this.defCharSB  = this.encodeTable[0][iconv.defaultCharSingleByte.charCodeAt(0)];
+    if (this.defCharSB === UNASSIGNED) this.defCharSB = this.encodeTable[0]['?'];
+    if (this.defCharSB === UNASSIGNED) this.defCharSB = "?".charCodeAt(0);
+}
+
+DBCSCodec.prototype.encoder = DBCSEncoder;
+DBCSCodec.prototype.decoder = DBCSDecoder;
+
+// Decoder helpers
+DBCSCodec.prototype._getDecodeTrieNode = function(addr) {
+    var bytes = [];
+    for (; addr > 0; addr >>>= 8)
+        bytes.push(addr & 0xFF);
+    if (bytes.length == 0)
+        bytes.push(0);
+
+    var node = this.decodeTables[0];
+    for (var i = bytes.length-1; i > 0; i--) { // Traverse nodes deeper into the trie.
+        var val = node[bytes[i]];
+
+        if (val == UNASSIGNED) { // Create new node.
+            node[bytes[i]] = NODE_START - this.decodeTables.length;
+            this.decodeTables.push(node = UNASSIGNED_NODE.slice(0));
+        }
+        else if (val <= NODE_START) { // Existing node.
+            node = this.decodeTables[NODE_START - val];
+        }
+        else
+            throw new Error("Overwrite byte in " + this.encodingName + ", addr: " + addr.toString(16));
+    }
+    return node;
+}
+
+
+DBCSCodec.prototype._addDecodeChunk = function(chunk) {
+    // First element of chunk is the hex mbcs code where we start.
+    var curAddr = parseInt(chunk[0], 16);
+
+    // Choose the decoding node where we'll write our chars.
+    var writeTable = this._getDecodeTrieNode(curAddr);
+    curAddr = curAddr & 0xFF;
+
+    // Write all other elements of the chunk to the table.
+    for (var k = 1; k < chunk.length; k++) {
+        var part = chunk[k];
+        if (typeof part === "string") { // String, write as-is.
+            for (var l = 0; l < part.length;) {
+                var code = part.charCodeAt(l++);
+                if (0xD800 <= code && code < 0xDC00) { // Decode surrogate
+                    var codeTrail = part.charCodeAt(l++);
+                    if (0xDC00 <= codeTrail && codeTrail < 0xE000)
+                        writeTable[curAddr++] = 0x10000 + (code - 0xD800) * 0x400 + (codeTrail - 0xDC00);
+                    else
+                        throw new Error("Incorrect surrogate pair in "  + this.encodingName + " at chunk " + chunk[0]);
+                }
+                else if (0x0FF0 < code && code <= 0x0FFF) { // Character sequence (our own encoding used)
+                    var len = 0xFFF - code + 2;
+                    var seq = [];
+                    for (var m = 0; m < len; m++)
+                        seq.push(part.charCodeAt(l++)); // Simple variation: don't support surrogates or subsequences in seq.
+
+                    writeTable[curAddr++] = SEQ_START - this.decodeTableSeq.length;
+                    this.decodeTableSeq.push(seq);
+                }
+                else
+                    writeTable[curAddr++] = code; // Basic char
+            }
+        } 
+        else if (typeof part === "number") { // Integer, meaning increasing sequence starting with prev character.
+            var charCode = writeTable[curAddr - 1] + 1;
+            for (var l = 0; l < part; l++)
+                writeTable[curAddr++] = charCode++;
+        }
+        else
+            throw new Error("Incorrect type '" + typeof part + "' given in "  + this.encodingName + " at chunk " + chunk[0]);
+    }
+    if (curAddr > 0xFF)
+        throw new Error("Incorrect chunk in "  + this.encodingName + " at addr " + chunk[0] + ": too long" + curAddr);
+}
+
+// Encoder helpers
+DBCSCodec.prototype._getEncodeBucket = function(uCode) {
+    var high = uCode >> 8; // This could be > 0xFF because of astral characters.
+    if (this.encodeTable[high] === undefined)
+        this.encodeTable[high] = UNASSIGNED_NODE.slice(0); // Create bucket on demand.
+    return this.encodeTable[high];
+}
+
+DBCSCodec.prototype._setEncodeChar = function(uCode, dbcsCode) {
+    var bucket = this._getEncodeBucket(uCode);
+    var low = uCode & 0xFF;
+    if (bucket[low] <= SEQ_START)
+        this.encodeTableSeq[SEQ_START-bucket[low]][DEF_CHAR] = dbcsCode; // There's already a sequence, set a single-char subsequence of it.
+    else if (bucket[low] == UNASSIGNED)
+        bucket[low] = dbcsCode;
+}
+
+DBCSCodec.prototype._setEncodeSequence = function(seq, dbcsCode) {
+    
+    // Get the root of character tree according to first character of the sequence.
+    var uCode = seq[0];
+    var bucket = this._getEncodeBucket(uCode);
+    var low = uCode & 0xFF;
+
+    var node;
+    if (bucket[low] <= SEQ_START) {
+        // There's already a sequence with  - use it.
+        node = this.encodeTableSeq[SEQ_START-bucket[low]];
+    }
+    else {
+        // There was no sequence object - allocate a new one.
+        node = {};
+        if (bucket[low] !== UNASSIGNED) node[DEF_CHAR] = bucket[low]; // If a char was set before - make it a single-char subsequence.
+        bucket[low] = SEQ_START - this.encodeTableSeq.length;
+        this.encodeTableSeq.push(node);
+    }
+
+    // Traverse the character tree, allocating new nodes as needed.
+    for (var j = 1; j < seq.length-1; j++) {
+        var oldVal = node[uCode];
+        if (typeof oldVal === 'object')
+            node = oldVal;
+        else {
+            node = node[uCode] = {}
+            if (oldVal !== undefined)
+                node[DEF_CHAR] = oldVal
+        }
+    }
+
+    // Set the leaf to given dbcsCode.
+    uCode = seq[seq.length-1];
+    node[uCode] = dbcsCode;
+}
+
+DBCSCodec.prototype._fillEncodeTable = function(nodeIdx, prefix, skipEncodeChars) {
+    var node = this.decodeTables[nodeIdx];
+    var hasValues = false;
+    var subNodeEmpty = {};
+    for (var i = 0; i < 0x100; i++) {
+        var uCode = node[i];
+        var mbCode = prefix + i;
+        if (skipEncodeChars[mbCode])
+            continue;
+
+        if (uCode >= 0) {
+            this._setEncodeChar(uCode, mbCode);
+            hasValues = true;
+        } else if (uCode <= NODE_START) {
+            var subNodeIdx = NODE_START - uCode;
+            if (!subNodeEmpty[subNodeIdx]) {  // Skip empty subtrees (they are too large in gb18030).
+                var newPrefix = (mbCode << 8) >>> 0;  // NOTE: '>>> 0' keeps 32-bit num positive.
+                if (this._fillEncodeTable(subNodeIdx, newPrefix, skipEncodeChars))
+                    hasValues = true;
+                else
+                    subNodeEmpty[subNodeIdx] = true;
+            }
+        } else if (uCode <= SEQ_START) {
+            this._setEncodeSequence(this.decodeTableSeq[SEQ_START - uCode], mbCode);
+            hasValues = true;
+        }
+    }
+    return hasValues;
+}
+
+
+
+// == Encoder ==================================================================
+
+function DBCSEncoder(options, codec) {
+    // Encoder state
+    this.leadSurrogate = -1;
+    this.seqObj = undefined;
+    
+    // Static data
+    this.encodeTable = codec.encodeTable;
+    this.encodeTableSeq = codec.encodeTableSeq;
+    this.defaultCharSingleByte = codec.defCharSB;
+    this.gb18030 = codec.gb18030;
+}
+
+DBCSEncoder.prototype.write = function(str) {
+    var newBuf = Buffer.alloc(str.length * (this.gb18030 ? 4 : 3)),
+        leadSurrogate = this.leadSurrogate,
+        seqObj = this.seqObj, nextChar = -1,
+        i = 0, j = 0;
+
+    while (true) {
+        // 0. Get next character.
+        if (nextChar === -1) {
+            if (i == str.length) break;
+            var uCode = str.charCodeAt(i++);
+        }
+        else {
+            var uCode = nextChar;
+            nextChar = -1;    
+        }
+
+        // 1. Handle surrogates.
+        if (0xD800 <= uCode && uCode < 0xE000) { // Char is one of surrogates.
+            if (uCode < 0xDC00) { // We've got lead surrogate.
+                if (leadSurrogate === -1) {
+                    leadSurrogate = uCode;
+                    continue;
+                } else {
+                    leadSurrogate = uCode;
+                    // Double lead surrogate found.
+                    uCode = UNASSIGNED;
+                }
+            } else { // We've got trail surrogate.
+                if (leadSurrogate !== -1) {
+                    uCode = 0x10000 + (leadSurrogate - 0xD800) * 0x400 + (uCode - 0xDC00);
+                    leadSurrogate = -1;
+                } else {
+                    // Incomplete surrogate pair - only trail surrogate found.
+                    uCode = UNASSIGNED;
+                }
+                
+            }
+        }
+        else if (leadSurrogate !== -1) {
+            // Incomplete surrogate pair - only lead surrogate found.
+            nextChar = uCode; uCode = UNASSIGNED; // Write an error, then current char.
+            leadSurrogate = -1;
+        }
+
+        // 2. Convert uCode character.
+        var dbcsCode = UNASSIGNED;
+        if (seqObj !== undefined && uCode != UNASSIGNED) { // We are in the middle of the sequence
+            var resCode = seqObj[uCode];
+            if (typeof resCode === 'object') { // Sequence continues.
+                seqObj = resCode;
+                continue;
+
+            } else if (typeof resCode == 'number') { // Sequence finished. Write it.
+                dbcsCode = resCode;
+
+            } else if (resCode == undefined) { // Current character is not part of the sequence.
+
+                // Try default character for this sequence
+                resCode = seqObj[DEF_CHAR];
+                if (resCode !== undefined) {
+                    dbcsCode = resCode; // Found. Write it.
+                    nextChar = uCode; // Current character will be written too in the next iteration.
+
+                } else {
+                    // TODO: What if we have no default? (resCode == undefined)
+                    // Then, we should write first char of the sequence as-is and try the rest recursively.
+                    // Didn't do it for now because no encoding has this situation yet.
+                    // Currently, just skip the sequence and write current char.
+                }
+            }
+            seqObj = undefined;
+        }
+        else if (uCode >= 0) {  // Regular character
+            var subtable = this.encodeTable[uCode >> 8];
+            if (subtable !== undefined)
+                dbcsCode = subtable[uCode & 0xFF];
+            
+            if (dbcsCode <= SEQ_START) { // Sequence start
+                seqObj = this.encodeTableSeq[SEQ_START-dbcsCode];
+                continue;
+            }
+
+            if (dbcsCode == UNASSIGNED && this.gb18030) {
+                // Use GB18030 algorithm to find character(s) to write.
+                var idx = findIdx(this.gb18030.uChars, uCode);
+                if (idx != -1) {
+                    var dbcsCode = this.gb18030.gbChars[idx] + (uCode - this.gb18030.uChars[idx]);
+                    newBuf[j++] = 0x81 + Math.floor(dbcsCode / 12600); dbcsCode = dbcsCode % 12600;
+                    newBuf[j++] = 0x30 + Math.floor(dbcsCode / 1260); dbcsCode = dbcsCode % 1260;
+                    newBuf[j++] = 0x81 + Math.floor(dbcsCode / 10); dbcsCode = dbcsCode % 10;
+                    newBuf[j++] = 0x30 + dbcsCode;
+                    continue;
+                }
+            }
+        }
+
+        // 3. Write dbcsCode character.
+        if (dbcsCode === UNASSIGNED)
+            dbcsCode = this.defaultCharSingleByte;
+        
+        if (dbcsCode < 0x100) {
+            newBuf[j++] = dbcsCode;
+        }
+        else if (dbcsCode < 0x10000) {
+            newBuf[j++] = dbcsCode >> 8;   // high byte
+            newBuf[j++] = dbcsCode & 0xFF; // low byte
+        }
+        else if (dbcsCode < 0x1000000) {
+            newBuf[j++] = dbcsCode >> 16;
+            newBuf[j++] = (dbcsCode >> 8) & 0xFF;
+            newBuf[j++] = dbcsCode & 0xFF;
+        } else {
+            newBuf[j++] = dbcsCode >>> 24;
+            newBuf[j++] = (dbcsCode >>> 16) & 0xFF;
+            newBuf[j++] = (dbcsCode >>> 8) & 0xFF;
+            newBuf[j++] = dbcsCode & 0xFF;
+        }
+    }
+
+    this.seqObj = seqObj;
+    this.leadSurrogate = leadSurrogate;
+    return newBuf.slice(0, j);
+}
+
+DBCSEncoder.prototype.end = function() {
+    if (this.leadSurrogate === -1 && this.seqObj === undefined)
+        return; // All clean. Most often case.
+
+    var newBuf = Buffer.alloc(10), j = 0;
+
+    if (this.seqObj) { // We're in the sequence.
+        var dbcsCode = this.seqObj[DEF_CHAR];
+        if (dbcsCode !== undefined) { // Write beginning of the sequence.
+            if (dbcsCode < 0x100) {
+                newBuf[j++] = dbcsCode;
+            }
+            else {
+                newBuf[j++] = dbcsCode >> 8;   // high byte
+                newBuf[j++] = dbcsCode & 0xFF; // low byte
+            }
+        } else {
+            // See todo above.
+        }
+        this.seqObj = undefined;
+    }
+
+    if (this.leadSurrogate !== -1) {
+        // Incomplete surrogate pair - only lead surrogate found.
+        newBuf[j++] = this.defaultCharSingleByte;
+        this.leadSurrogate = -1;
+    }
+    
+    return newBuf.slice(0, j);
+}
+
+// Export for testing
+DBCSEncoder.prototype.findIdx = findIdx;
+
+
+// == Decoder ==================================================================
+
+function DBCSDecoder(options, codec) {
+    // Decoder state
+    this.nodeIdx = 0;
+    this.prevBytes = [];
+
+    // Static data
+    this.decodeTables = codec.decodeTables;
+    this.decodeTableSeq = codec.decodeTableSeq;
+    this.defaultCharUnicode = codec.defaultCharUnicode;
+    this.gb18030 = codec.gb18030;
+}
+
+DBCSDecoder.prototype.write = function(buf) {
+    var newBuf = Buffer.alloc(buf.length*2),
+        nodeIdx = this.nodeIdx, 
+        prevBytes = this.prevBytes, prevOffset = this.prevBytes.length,
+        seqStart = -this.prevBytes.length, // idx of the start of current parsed sequence.
+        uCode;
+
+    for (var i = 0, j = 0; i < buf.length; i++) {
+        var curByte = (i >= 0) ? buf[i] : prevBytes[i + prevOffset];
+
+        // Lookup in current trie node.
+        var uCode = this.decodeTables[nodeIdx][curByte];
+
+        if (uCode >= 0) { 
+            // Normal character, just use it.
+        }
+        else if (uCode === UNASSIGNED) { // Unknown char.
+            // TODO: Callback with seq.
+            uCode = this.defaultCharUnicode.charCodeAt(0);
+            i = seqStart; // Skip one byte ('i' will be incremented by the for loop) and try to parse again.
+        }
+        else if (uCode === GB18030_CODE) {
+            if (i >= 3) {
+                var ptr = (buf[i-3]-0x81)*12600 + (buf[i-2]-0x30)*1260 + (buf[i-1]-0x81)*10 + (curByte-0x30);
+            } else {
+                var ptr = (prevBytes[i-3+prevOffset]-0x81)*12600 + 
+                          (((i-2 >= 0) ? buf[i-2] : prevBytes[i-2+prevOffset])-0x30)*1260 + 
+                          (((i-1 >= 0) ? buf[i-1] : prevBytes[i-1+prevOffset])-0x81)*10 + 
+                          (curByte-0x30);
+            }
+            var idx = findIdx(this.gb18030.gbChars, ptr);
+            uCode = this.gb18030.uChars[idx] + ptr - this.gb18030.gbChars[idx];
+        }
+        else if (uCode <= NODE_START) { // Go to next trie node.
+            nodeIdx = NODE_START - uCode;
+            continue;
+        }
+        else if (uCode <= SEQ_START) { // Output a sequence of chars.
+            var seq = this.decodeTableSeq[SEQ_START - uCode];
+            for (var k = 0; k < seq.length - 1; k++) {
+                uCode = seq[k];
+                newBuf[j++] = uCode & 0xFF;
+                newBuf[j++] = uCode >> 8;
+            }
+            uCode = seq[seq.length-1];
+        }
+        else
+            throw new Error("iconv-lite internal error: invalid decoding table value " + uCode + " at " + nodeIdx + "/" + curByte);
+
+        // Write the character to buffer, handling higher planes using surrogate pair.
+        if (uCode >= 0x10000) { 
+            uCode -= 0x10000;
+            var uCodeLead = 0xD800 | (uCode >> 10);
+            newBuf[j++] = uCodeLead & 0xFF;
+            newBuf[j++] = uCodeLead >> 8;
+
+            uCode = 0xDC00 | (uCode & 0x3FF);
+        }
+        newBuf[j++] = uCode & 0xFF;
+        newBuf[j++] = uCode >> 8;
+
+        // Reset trie node.
+        nodeIdx = 0; seqStart = i+1;
+    }
+
+    this.nodeIdx = nodeIdx;
+    this.prevBytes = (seqStart >= 0)
+        ? Array.prototype.slice.call(buf, seqStart)
+        : prevBytes.slice(seqStart + prevOffset).concat(Array.prototype.slice.call(buf));
+
+    return newBuf.slice(0, j).toString('ucs2');
+}
+
+DBCSDecoder.prototype.end = function() {
+    var ret = '';
+
+    // Try to parse all remaining chars.
+    while (this.prevBytes.length > 0) {
+        // Skip 1 character in the buffer.
+        ret += this.defaultCharUnicode;
+        var bytesArr = this.prevBytes.slice(1);
+
+        // Parse remaining as usual.
+        this.prevBytes = [];
+        this.nodeIdx = 0;
+        if (bytesArr.length > 0)
+            ret += this.write(bytesArr);
+    }
+
+    this.prevBytes = [];
+    this.nodeIdx = 0;
+    return ret;
+}
+
+// Binary search for GB18030. Returns largest i such that table[i] <= val.
+function findIdx(table, val) {
+    if (table[0] > val)
+        return -1;
+
+    var l = 0, r = table.length;
+    while (l < r-1) { // always table[l] <= val < table[r]
+        var mid = l + ((r-l+1) >> 1);
+        if (table[mid] <= val)
+            l = mid;
+        else
+            r = mid;
+    }
+    return l;
+}
+
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/dbcs-data.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/dbcs-data.js
new file mode 100644
index 0000000..0d17e58
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/dbcs-data.js
@@ -0,0 +1,188 @@
+"use strict";
+
+// Description of supported double byte encodings and aliases.
+// Tables are not require()-d until they are needed to speed up library load.
+// require()-s are direct to support Browserify.
+
+module.exports = {
+    
+    // == Japanese/ShiftJIS ====================================================
+    // All japanese encodings are based on JIS X set of standards:
+    // JIS X 0201 - Single-byte encoding of ASCII + ¥ + Kana chars at 0xA1-0xDF.
+    // JIS X 0208 - Main set of 6879 characters, placed in 94x94 plane, to be encoded by 2 bytes. 
+    //              Has several variations in 1978, 1983, 1990 and 1997.
+    // JIS X 0212 - Supplementary plane of 6067 chars in 94x94 plane. 1990. Effectively dead.
+    // JIS X 0213 - Extension and modern replacement of 0208 and 0212. Total chars: 11233.
+    //              2 planes, first is superset of 0208, second - revised 0212.
+    //              Introduced in 2000, revised 2004. Some characters are in Unicode Plane 2 (0x2xxxx)
+
+    // Byte encodings are:
+    //  * Shift_JIS: Compatible with 0201, uses not defined chars in top half as lead bytes for double-byte
+    //               encoding of 0208. Lead byte ranges: 0x81-0x9F, 0xE0-0xEF; Trail byte ranges: 0x40-0x7E, 0x80-0x9E, 0x9F-0xFC.
+    //               Windows CP932 is a superset of Shift_JIS. Some companies added more chars, notably KDDI.
+    //  * EUC-JP:    Up to 3 bytes per character. Used mostly on *nixes.
+    //               0x00-0x7F       - lower part of 0201
+    //               0x8E, 0xA1-0xDF - upper part of 0201
+    //               (0xA1-0xFE)x2   - 0208 plane (94x94).
+    //               0x8F, (0xA1-0xFE)x2 - 0212 plane (94x94).
+    //  * JIS X 208: 7-bit, direct encoding of 0208. Byte ranges: 0x21-0x7E (94 values). Uncommon.
+    //               Used as-is in ISO2022 family.
+    //  * ISO2022-JP: Stateful encoding, with escape sequences to switch between ASCII, 
+    //                0201-1976 Roman, 0208-1978, 0208-1983.
+    //  * ISO2022-JP-1: Adds esc seq for 0212-1990.
+    //  * ISO2022-JP-2: Adds esc seq for GB2313-1980, KSX1001-1992, ISO8859-1, ISO8859-7.
+    //  * ISO2022-JP-3: Adds esc seq for 0201-1976 Kana set, 0213-2000 Planes 1, 2.
+    //  * ISO2022-JP-2004: Adds 0213-2004 Plane 1.
+    //
+    // After JIS X 0213 appeared, Shift_JIS-2004, EUC-JISX0213 and ISO2022-JP-2004 followed, with just changing the planes.
+    //
+    // Overall, it seems that it's a mess :( http://www8.plala.or.jp/tkubota1/unicode-symbols-map2.html
+
+    'shiftjis': {
+        type: '_dbcs',
+        table: function() { return require('./tables/shiftjis.json') },
+        encodeAdd: {'\u00a5': 0x5C, '\u203E': 0x7E},
+        encodeSkipVals: [{from: 0xED40, to: 0xF940}],
+    },
+    'csshiftjis': 'shiftjis',
+    'mskanji': 'shiftjis',
+    'sjis': 'shiftjis',
+    'windows31j': 'shiftjis',
+    'ms31j': 'shiftjis',
+    'xsjis': 'shiftjis',
+    'windows932': 'shiftjis',
+    'ms932': 'shiftjis',
+    '932': 'shiftjis',
+    'cp932': 'shiftjis',
+
+    'eucjp': {
+        type: '_dbcs',
+        table: function() { return require('./tables/eucjp.json') },
+        encodeAdd: {'\u00a5': 0x5C, '\u203E': 0x7E},
+    },
+
+    // TODO: KDDI extension to Shift_JIS
+    // TODO: IBM CCSID 942 = CP932, but F0-F9 custom chars and other char changes.
+    // TODO: IBM CCSID 943 = Shift_JIS = CP932 with original Shift_JIS lower 128 chars.
+
+
+    // == Chinese/GBK ==========================================================
+    // http://en.wikipedia.org/wiki/GBK
+    // We mostly implement W3C recommendation: https://www.w3.org/TR/encoding/#gbk-encoder
+
+    // Oldest GB2312 (1981, ~7600 chars) is a subset of CP936
+    'gb2312': 'cp936',
+    'gb231280': 'cp936',
+    'gb23121980': 'cp936',
+    'csgb2312': 'cp936',
+    'csiso58gb231280': 'cp936',
+    'euccn': 'cp936',
+
+    // Microsoft's CP936 is a subset and approximation of GBK.
+    'windows936': 'cp936',
+    'ms936': 'cp936',
+    '936': 'cp936',
+    'cp936': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp936.json') },
+    },
+
+    // GBK (~22000 chars) is an extension of CP936 that added user-mapped chars and some other.
+    'gbk': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp936.json').concat(require('./tables/gbk-added.json')) },
+    },
+    'xgbk': 'gbk',
+    'isoir58': 'gbk',
+
+    // GB18030 is an algorithmic extension of GBK.
+    // Main source: https://www.w3.org/TR/encoding/#gbk-encoder
+    // http://icu-project.org/docs/papers/gb18030.html
+    // http://source.icu-project.org/repos/icu/data/trunk/charset/data/xml/gb-18030-2000.xml
+    // http://www.khngai.com/chinese/charmap/tblgbk.php?page=0
+    'gb18030': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp936.json').concat(require('./tables/gbk-added.json')) },
+        gb18030: function() { return require('./tables/gb18030-ranges.json') },
+        encodeSkipVals: [0x80],
+        encodeAdd: {'€': 0xA2E3},
+    },
+
+    'chinese': 'gb18030',
+
+
+    // == Korean ===============================================================
+    // EUC-KR, KS_C_5601 and KS X 1001 are exactly the same.
+    'windows949': 'cp949',
+    'ms949': 'cp949',
+    '949': 'cp949',
+    'cp949': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp949.json') },
+    },
+
+    'cseuckr': 'cp949',
+    'csksc56011987': 'cp949',
+    'euckr': 'cp949',
+    'isoir149': 'cp949',
+    'korean': 'cp949',
+    'ksc56011987': 'cp949',
+    'ksc56011989': 'cp949',
+    'ksc5601': 'cp949',
+
+
+    // == Big5/Taiwan/Hong Kong ================================================
+    // There are lots of tables for Big5 and cp950. Please see the following links for history:
+    // http://moztw.org/docs/big5/  http://www.haible.de/bruno/charsets/conversion-tables/Big5.html
+    // Variations, in roughly number of defined chars:
+    //  * Windows CP 950: Microsoft variant of Big5. Canonical: http://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP950.TXT
+    //  * Windows CP 951: Microsoft variant of Big5-HKSCS-2001. Seems to be never public. http://me.abelcheung.org/articles/research/what-is-cp951/
+    //  * Big5-2003 (Taiwan standard) almost superset of cp950.
+    //  * Unicode-at-on (UAO) / Mozilla 1.8. Falling out of use on the Web. Not supported by other browsers.
+    //  * Big5-HKSCS (-2001, -2004, -2008). Hong Kong standard. 
+    //    many unicode code points moved from PUA to Supplementary plane (U+2XXXX) over the years.
+    //    Plus, it has 4 combining sequences.
+    //    Seems that Mozilla refused to support it for 10 yrs. https://bugzilla.mozilla.org/show_bug.cgi?id=162431 https://bugzilla.mozilla.org/show_bug.cgi?id=310299
+    //    because big5-hkscs is the only encoding to include astral characters in non-algorithmic way.
+    //    Implementations are not consistent within browsers; sometimes labeled as just big5.
+    //    MS Internet Explorer switches from big5 to big5-hkscs when a patch applied.
+    //    Great discussion & recap of what's going on https://bugzilla.mozilla.org/show_bug.cgi?id=912470#c31
+    //    In the encoder, it might make sense to support encoding old PUA mappings to Big5 bytes seq-s.
+    //    Official spec: http://www.ogcio.gov.hk/en/business/tech_promotion/ccli/terms/doc/2003cmp_2008.txt
+    //                   http://www.ogcio.gov.hk/tc/business/tech_promotion/ccli/terms/doc/hkscs-2008-big5-iso.txt
+    // 
+    // Current understanding of how to deal with Big5(-HKSCS) is in the Encoding Standard, http://encoding.spec.whatwg.org/#big5-encoder
+    // Unicode mapping (http://www.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/OTHER/BIG5.TXT) is said to be wrong.
+
+    'windows950': 'cp950',
+    'ms950': 'cp950',
+    '950': 'cp950',
+    'cp950': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp950.json') },
+    },
+
+    // Big5 has many variations and is an extension of cp950. We use Encoding Standard's as a consensus.
+    'big5': 'big5hkscs',
+    'big5hkscs': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp950.json').concat(require('./tables/big5-added.json')) },
+        encodeSkipVals: [
+            // Although Encoding Standard says we should avoid encoding to HKSCS area (See Step 1 of
+            // https://encoding.spec.whatwg.org/#index-big5-pointer), we still do it to increase compatibility with ICU.
+            // But if a single unicode point can be encoded both as HKSCS and regular Big5, we prefer the latter.
+            0x8e69, 0x8e6f, 0x8e7e, 0x8eab, 0x8eb4, 0x8ecd, 0x8ed0, 0x8f57, 0x8f69, 0x8f6e, 0x8fcb, 0x8ffe,
+            0x906d, 0x907a, 0x90c4, 0x90dc, 0x90f1, 0x91bf, 0x92af, 0x92b0, 0x92b1, 0x92b2, 0x92d1, 0x9447, 0x94ca,
+            0x95d9, 0x96fc, 0x9975, 0x9b76, 0x9b78, 0x9b7b, 0x9bc6, 0x9bde, 0x9bec, 0x9bf6, 0x9c42, 0x9c53, 0x9c62,
+            0x9c68, 0x9c6b, 0x9c77, 0x9cbc, 0x9cbd, 0x9cd0, 0x9d57, 0x9d5a, 0x9dc4, 0x9def, 0x9dfb, 0x9ea9, 0x9eef,
+            0x9efd, 0x9f60, 0x9fcb, 0xa077, 0xa0dc, 0xa0df, 0x8fcc, 0x92c8, 0x9644, 0x96ed,
+
+            // Step 2 of https://encoding.spec.whatwg.org/#index-big5-pointer: Use last pointer for U+2550, U+255E, U+2561, U+256A, U+5341, or U+5345
+            0xa2a4, 0xa2a5, 0xa2a7, 0xa2a6, 0xa2cc, 0xa2ce,
+        ],
+    },
+
+    'cnbig5': 'big5hkscs',
+    'csbig5': 'big5hkscs',
+    'xxbig5': 'big5hkscs',
+};
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/index.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/index.js
new file mode 100644
index 0000000..d95c244
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/index.js
@@ -0,0 +1,23 @@
+"use strict";
+
+// Update this array if you add/rename/remove files in this directory.
+// We support Browserify by skipping automatic module discovery and requiring modules directly.
+var modules = [
+    require("./internal"),
+    require("./utf32"),
+    require("./utf16"),
+    require("./utf7"),
+    require("./sbcs-codec"),
+    require("./sbcs-data"),
+    require("./sbcs-data-generated"),
+    require("./dbcs-codec"),
+    require("./dbcs-data"),
+];
+
+// Put all encoding/alias/codec definitions to single object and export it.
+for (var i = 0; i < modules.length; i++) {
+    var module = modules[i];
+    for (var enc in module)
+        if (Object.prototype.hasOwnProperty.call(module, enc))
+            exports[enc] = module[enc];
+}
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/internal.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/internal.js
new file mode 100644
index 0000000..dc1074f
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/internal.js
@@ -0,0 +1,198 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// Export Node.js internal encodings.
+
+module.exports = {
+    // Encodings
+    utf8:   { type: "_internal", bomAware: true},
+    cesu8:  { type: "_internal", bomAware: true},
+    unicode11utf8: "utf8",
+
+    ucs2:   { type: "_internal", bomAware: true},
+    utf16le: "ucs2",
+
+    binary: { type: "_internal" },
+    base64: { type: "_internal" },
+    hex:    { type: "_internal" },
+
+    // Codec.
+    _internal: InternalCodec,
+};
+
+//------------------------------------------------------------------------------
+
+function InternalCodec(codecOptions, iconv) {
+    this.enc = codecOptions.encodingName;
+    this.bomAware = codecOptions.bomAware;
+
+    if (this.enc === "base64")
+        this.encoder = InternalEncoderBase64;
+    else if (this.enc === "cesu8") {
+        this.enc = "utf8"; // Use utf8 for decoding.
+        this.encoder = InternalEncoderCesu8;
+
+        // Add decoder for versions of Node not supporting CESU-8
+        if (Buffer.from('eda0bdedb2a9', 'hex').toString() !== '💩') {
+            this.decoder = InternalDecoderCesu8;
+            this.defaultCharUnicode = iconv.defaultCharUnicode;
+        }
+    }
+}
+
+InternalCodec.prototype.encoder = InternalEncoder;
+InternalCodec.prototype.decoder = InternalDecoder;
+
+//------------------------------------------------------------------------------
+
+// We use node.js internal decoder. Its signature is the same as ours.
+var StringDecoder = require('string_decoder').StringDecoder;
+
+if (!StringDecoder.prototype.end) // Node v0.8 doesn't have this method.
+    StringDecoder.prototype.end = function() {};
+
+
+function InternalDecoder(options, codec) {
+    this.decoder = new StringDecoder(codec.enc);
+}
+
+InternalDecoder.prototype.write = function(buf) {
+    if (!Buffer.isBuffer(buf)) {
+        buf = Buffer.from(buf);
+    }
+
+    return this.decoder.write(buf);
+}
+
+InternalDecoder.prototype.end = function() {
+    return this.decoder.end();
+}
+
+
+//------------------------------------------------------------------------------
+// Encoder is mostly trivial
+
+function InternalEncoder(options, codec) {
+    this.enc = codec.enc;
+}
+
+InternalEncoder.prototype.write = function(str) {
+    return Buffer.from(str, this.enc);
+}
+
+InternalEncoder.prototype.end = function() {
+}
+
+
+//------------------------------------------------------------------------------
+// Except base64 encoder, which must keep its state.
+
+function InternalEncoderBase64(options, codec) {
+    this.prevStr = '';
+}
+
+InternalEncoderBase64.prototype.write = function(str) {
+    str = this.prevStr + str;
+    var completeQuads = str.length - (str.length % 4);
+    this.prevStr = str.slice(completeQuads);
+    str = str.slice(0, completeQuads);
+
+    return Buffer.from(str, "base64");
+}
+
+InternalEncoderBase64.prototype.end = function() {
+    return Buffer.from(this.prevStr, "base64");
+}
+
+
+//------------------------------------------------------------------------------
+// CESU-8 encoder is also special.
+
+function InternalEncoderCesu8(options, codec) {
+}
+
+InternalEncoderCesu8.prototype.write = function(str) {
+    var buf = Buffer.alloc(str.length * 3), bufIdx = 0;
+    for (var i = 0; i < str.length; i++) {
+        var charCode = str.charCodeAt(i);
+        // Naive implementation, but it works because CESU-8 is especially easy
+        // to convert from UTF-16 (which all JS strings are encoded in).
+        if (charCode < 0x80)
+            buf[bufIdx++] = charCode;
+        else if (charCode < 0x800) {
+            buf[bufIdx++] = 0xC0 + (charCode >>> 6);
+            buf[bufIdx++] = 0x80 + (charCode & 0x3f);
+        }
+        else { // charCode will always be < 0x10000 in javascript.
+            buf[bufIdx++] = 0xE0 + (charCode >>> 12);
+            buf[bufIdx++] = 0x80 + ((charCode >>> 6) & 0x3f);
+            buf[bufIdx++] = 0x80 + (charCode & 0x3f);
+        }
+    }
+    return buf.slice(0, bufIdx);
+}
+
+InternalEncoderCesu8.prototype.end = function() {
+}
+
+//------------------------------------------------------------------------------
+// CESU-8 decoder is not implemented in Node v4.0+
+
+function InternalDecoderCesu8(options, codec) {
+    this.acc = 0;
+    this.contBytes = 0;
+    this.accBytes = 0;
+    this.defaultCharUnicode = codec.defaultCharUnicode;
+}
+
+InternalDecoderCesu8.prototype.write = function(buf) {
+    var acc = this.acc, contBytes = this.contBytes, accBytes = this.accBytes, 
+        res = '';
+    for (var i = 0; i < buf.length; i++) {
+        var curByte = buf[i];
+        if ((curByte & 0xC0) !== 0x80) { // Leading byte
+            if (contBytes > 0) { // Previous code is invalid
+                res += this.defaultCharUnicode;
+                contBytes = 0;
+            }
+
+            if (curByte < 0x80) { // Single-byte code
+                res += String.fromCharCode(curByte);
+            } else if (curByte < 0xE0) { // Two-byte code
+                acc = curByte & 0x1F;
+                contBytes = 1; accBytes = 1;
+            } else if (curByte < 0xF0) { // Three-byte code
+                acc = curByte & 0x0F;
+                contBytes = 2; accBytes = 1;
+            } else { // Four or more are not supported for CESU-8.
+                res += this.defaultCharUnicode;
+            }
+        } else { // Continuation byte
+            if (contBytes > 0) { // We're waiting for it.
+                acc = (acc << 6) | (curByte & 0x3f);
+                contBytes--; accBytes++;
+                if (contBytes === 0) {
+                    // Check for overlong encoding, but support Modified UTF-8 (encoding NULL as C0 80)
+                    if (accBytes === 2 && acc < 0x80 && acc > 0)
+                        res += this.defaultCharUnicode;
+                    else if (accBytes === 3 && acc < 0x800)
+                        res += this.defaultCharUnicode;
+                    else
+                        // Actually add character.
+                        res += String.fromCharCode(acc);
+                }
+            } else { // Unexpected continuation byte
+                res += this.defaultCharUnicode;
+            }
+        }
+    }
+    this.acc = acc; this.contBytes = contBytes; this.accBytes = accBytes;
+    return res;
+}
+
+InternalDecoderCesu8.prototype.end = function() {
+    var res = 0;
+    if (this.contBytes > 0)
+        res += this.defaultCharUnicode;
+    return res;
+}
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/sbcs-codec.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/sbcs-codec.js
new file mode 100644
index 0000000..abac5ff
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/sbcs-codec.js
@@ -0,0 +1,72 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// Single-byte codec. Needs a 'chars' string parameter that contains 256 or 128 chars that
+// correspond to encoded bytes (if 128 - then lower half is ASCII). 
+
+exports._sbcs = SBCSCodec;
+function SBCSCodec(codecOptions, iconv) {
+    if (!codecOptions)
+        throw new Error("SBCS codec is called without the data.")
+    
+    // Prepare char buffer for decoding.
+    if (!codecOptions.chars || (codecOptions.chars.length !== 128 && codecOptions.chars.length !== 256))
+        throw new Error("Encoding '"+codecOptions.type+"' has incorrect 'chars' (must be of len 128 or 256)");
+    
+    if (codecOptions.chars.length === 128) {
+        var asciiString = "";
+        for (var i = 0; i < 128; i++)
+            asciiString += String.fromCharCode(i);
+        codecOptions.chars = asciiString + codecOptions.chars;
+    }
+
+    this.decodeBuf = Buffer.from(codecOptions.chars, 'ucs2');
+    
+    // Encoding buffer.
+    var encodeBuf = Buffer.alloc(65536, iconv.defaultCharSingleByte.charCodeAt(0));
+
+    for (var i = 0; i < codecOptions.chars.length; i++)
+        encodeBuf[codecOptions.chars.charCodeAt(i)] = i;
+
+    this.encodeBuf = encodeBuf;
+}
+
+SBCSCodec.prototype.encoder = SBCSEncoder;
+SBCSCodec.prototype.decoder = SBCSDecoder;
+
+
+function SBCSEncoder(options, codec) {
+    this.encodeBuf = codec.encodeBuf;
+}
+
+SBCSEncoder.prototype.write = function(str) {
+    var buf = Buffer.alloc(str.length);
+    for (var i = 0; i < str.length; i++)
+        buf[i] = this.encodeBuf[str.charCodeAt(i)];
+    
+    return buf;
+}
+
+SBCSEncoder.prototype.end = function() {
+}
+
+
+function SBCSDecoder(options, codec) {
+    this.decodeBuf = codec.decodeBuf;
+}
+
+SBCSDecoder.prototype.write = function(buf) {
+    // Strings are immutable in JS -> we use ucs2 buffer to speed up computations.
+    var decodeBuf = this.decodeBuf;
+    var newBuf = Buffer.alloc(buf.length*2);
+    var idx1 = 0, idx2 = 0;
+    for (var i = 0; i < buf.length; i++) {
+        idx1 = buf[i]*2; idx2 = i*2;
+        newBuf[idx2] = decodeBuf[idx1];
+        newBuf[idx2+1] = decodeBuf[idx1+1];
+    }
+    return newBuf.toString('ucs2');
+}
+
+SBCSDecoder.prototype.end = function() {
+}
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/sbcs-data-generated.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/sbcs-data-generated.js
new file mode 100644
index 0000000..9b48236
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/sbcs-data-generated.js
@@ -0,0 +1,451 @@
+"use strict";
+
+// Generated data for sbcs codec. Don't edit manually. Regenerate using generation/gen-sbcs.js script.
+module.exports = {
+  "437": "cp437",
+  "737": "cp737",
+  "775": "cp775",
+  "850": "cp850",
+  "852": "cp852",
+  "855": "cp855",
+  "856": "cp856",
+  "857": "cp857",
+  "858": "cp858",
+  "860": "cp860",
+  "861": "cp861",
+  "862": "cp862",
+  "863": "cp863",
+  "864": "cp864",
+  "865": "cp865",
+  "866": "cp866",
+  "869": "cp869",
+  "874": "windows874",
+  "922": "cp922",
+  "1046": "cp1046",
+  "1124": "cp1124",
+  "1125": "cp1125",
+  "1129": "cp1129",
+  "1133": "cp1133",
+  "1161": "cp1161",
+  "1162": "cp1162",
+  "1163": "cp1163",
+  "1250": "windows1250",
+  "1251": "windows1251",
+  "1252": "windows1252",
+  "1253": "windows1253",
+  "1254": "windows1254",
+  "1255": "windows1255",
+  "1256": "windows1256",
+  "1257": "windows1257",
+  "1258": "windows1258",
+  "28591": "iso88591",
+  "28592": "iso88592",
+  "28593": "iso88593",
+  "28594": "iso88594",
+  "28595": "iso88595",
+  "28596": "iso88596",
+  "28597": "iso88597",
+  "28598": "iso88598",
+  "28599": "iso88599",
+  "28600": "iso885910",
+  "28601": "iso885911",
+  "28603": "iso885913",
+  "28604": "iso885914",
+  "28605": "iso885915",
+  "28606": "iso885916",
+  "windows874": {
+    "type": "_sbcs",
+    "chars": "€����…�����������‘’“”•–—�������� กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู����฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛����"
+  },
+  "win874": "windows874",
+  "cp874": "windows874",
+  "windows1250": {
+    "type": "_sbcs",
+    "chars": "€�‚�„…†‡�‰Š‹ŚŤŽŹ�‘’“”•–—�™š›śťžź ˇ˘Ł¤Ą¦§¨©Ş«¬®Ż°±˛ł´µ¶·¸ąş»Ľ˝ľżŔÁÂĂÄĹĆÇČÉĘËĚÍÎĎĐŃŇÓÔŐÖ×ŘŮÚŰÜÝŢßŕáâăäĺćçčéęëěíîďđńňóôőö÷řůúűüýţ˙"
+  },
+  "win1250": "windows1250",
+  "cp1250": "windows1250",
+  "windows1251": {
+    "type": "_sbcs",
+    "chars": "ЂЃ‚ѓ„…†‡€‰Љ‹ЊЌЋЏђ‘’“”•–—�™љ›њќћџ ЎўЈ¤Ґ¦§Ё©Є«¬®Ї°±Ііґµ¶·ё№є»јЅѕїАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя"
+  },
+  "win1251": "windows1251",
+  "cp1251": "windows1251",
+  "windows1252": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡ˆ‰Š‹Œ�Ž��‘’“”•–—˜™š›œ�žŸ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "win1252": "windows1252",
+  "cp1252": "windows1252",
+  "windows1253": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡�‰�‹�����‘’“”•–—�™�›���� ΅Ά£¤¥¦§¨©�«¬®―°±²³΄µ¶·ΈΉΊ»Ό½ΎΏΐΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡ�ΣΤΥΦΧΨΩΪΫάέήίΰαβγδεζηθικλμνξοπρςστυφχψωϊϋόύώ�"
+  },
+  "win1253": "windows1253",
+  "cp1253": "windows1253",
+  "windows1254": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡ˆ‰Š‹Œ����‘’“”•–—˜™š›œ��Ÿ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏĞÑÒÓÔÕÖ×ØÙÚÛÜİŞßàáâãäåæçèéêëìíîïğñòóôõö÷øùúûüışÿ"
+  },
+  "win1254": "windows1254",
+  "cp1254": "windows1254",
+  "windows1255": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡ˆ‰�‹�����‘’“”•–—˜™�›���� ¡¢£₪¥¦§¨©×«¬®¯°±²³´µ¶·¸¹÷»¼½¾¿ְֱֲֳִֵֶַָֹֺֻּֽ־ֿ׀ׁׂ׃װױײ׳״�������אבגדהוזחטיךכלםמןנסעףפץצקרשת��‎‏�"
+  },
+  "win1255": "windows1255",
+  "cp1255": "windows1255",
+  "windows1256": {
+    "type": "_sbcs",
+    "chars": "€پ‚ƒ„…†‡ˆ‰ٹ‹Œچژڈگ‘’“”•–—ک™ڑ›œ‌‍ں ،¢£¤¥¦§¨©ھ«¬®¯°±²³´µ¶·¸¹؛»¼½¾؟ہءآأؤإئابةتثجحخدذرزسشصض×طظعغـفقكàلâمنهوçèéêëىيîïًٌٍَôُِ÷ّùْûü‎‏ے"
+  },
+  "win1256": "windows1256",
+  "cp1256": "windows1256",
+  "windows1257": {
+    "type": "_sbcs",
+    "chars": "€�‚�„…†‡�‰�‹�¨ˇ¸�‘’“”•–—�™�›�¯˛� �¢£¤�¦§Ø©Ŗ«¬®Æ°±²³´µ¶·ø¹ŗ»¼½¾æĄĮĀĆÄÅĘĒČÉŹĖĢĶĪĻŠŃŅÓŌÕÖ×ŲŁŚŪÜŻŽßąįāćäåęēčéźėģķīļšńņóōõö÷ųłśūüżž˙"
+  },
+  "win1257": "windows1257",
+  "cp1257": "windows1257",
+  "windows1258": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡ˆ‰�‹Œ����‘’“”•–—˜™�›œ��Ÿ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂĂÄÅÆÇÈÉÊË̀ÍÎÏĐÑ̉ÓÔƠÖ×ØÙÚÛÜỮßàáâăäåæçèéêë́íîïđṇ̃óôơö÷øùúûüư₫ÿ"
+  },
+  "win1258": "windows1258",
+  "cp1258": "windows1258",
+  "iso88591": {
+    "type": "_sbcs",
+    "chars": " ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "cp28591": "iso88591",
+  "iso88592": {
+    "type": "_sbcs",
+    "chars": " Ą˘Ł¤ĽŚ§¨ŠŞŤŹŽŻ°ą˛ł´ľśˇ¸šşťź˝žżŔÁÂĂÄĹĆÇČÉĘËĚÍÎĎĐŃŇÓÔŐÖ×ŘŮÚŰÜÝŢßŕáâăäĺćçčéęëěíîďđńňóôőö÷řůúűüýţ˙"
+  },
+  "cp28592": "iso88592",
+  "iso88593": {
+    "type": "_sbcs",
+    "chars": " Ħ˘£¤�Ĥ§¨İŞĞĴ�Ż°ħ²³´µĥ·¸ışğĵ½�żÀÁÂ�ÄĊĈÇÈÉÊËÌÍÎÏ�ÑÒÓÔĠÖ×ĜÙÚÛÜŬŜßàáâ�äċĉçèéêëìíîï�ñòóôġö÷ĝùúûüŭŝ˙"
+  },
+  "cp28593": "iso88593",
+  "iso88594": {
+    "type": "_sbcs",
+    "chars": " ĄĸŖ¤ĨĻ§¨ŠĒĢŦŽ¯°ą˛ŗ´ĩļˇ¸šēģŧŊžŋĀÁÂÃÄÅÆĮČÉĘËĖÍÎĪĐŅŌĶÔÕÖ×ØŲÚÛÜŨŪßāáâãäåæįčéęëėíîīđņōķôõö÷øųúûüũū˙"
+  },
+  "cp28594": "iso88594",
+  "iso88595": {
+    "type": "_sbcs",
+    "chars": " ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя№ёђѓєѕіїјљњћќ§ўџ"
+  },
+  "cp28595": "iso88595",
+  "iso88596": {
+    "type": "_sbcs",
+    "chars": " ���¤�������،�������������؛���؟�ءآأؤإئابةتثجحخدذرزسشصضطظعغ�����ـفقكلمنهوىيًٌٍَُِّْ�������������"
+  },
+  "cp28596": "iso88596",
+  "iso88597": {
+    "type": "_sbcs",
+    "chars": " ‘’£€₯¦§¨©ͺ«¬�―°±²³΄΅Ά·ΈΉΊ»Ό½ΎΏΐΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡ�ΣΤΥΦΧΨΩΪΫάέήίΰαβγδεζηθικλμνξοπρςστυφχψωϊϋόύώ�"
+  },
+  "cp28597": "iso88597",
+  "iso88598": {
+    "type": "_sbcs",
+    "chars": " �¢£¤¥¦§¨©×«¬®¯°±²³´µ¶·¸¹÷»¼½¾��������������������������������‗אבגדהוזחטיךכלםמןנסעףפץצקרשת��‎‏�"
+  },
+  "cp28598": "iso88598",
+  "iso88599": {
+    "type": "_sbcs",
+    "chars": " ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏĞÑÒÓÔÕÖ×ØÙÚÛÜİŞßàáâãäåæçèéêëìíîïğñòóôõö÷øùúûüışÿ"
+  },
+  "cp28599": "iso88599",
+  "iso885910": {
+    "type": "_sbcs",
+    "chars": " ĄĒĢĪĨĶ§ĻĐŠŦŽŪŊ°ąēģīĩķ·ļđšŧž―ūŋĀÁÂÃÄÅÆĮČÉĘËĖÍÎÏÐŅŌÓÔÕÖŨØŲÚÛÜÝÞßāáâãäåæįčéęëėíîïðņōóôõöũøųúûüýþĸ"
+  },
+  "cp28600": "iso885910",
+  "iso885911": {
+    "type": "_sbcs",
+    "chars": " กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู����฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛����"
+  },
+  "cp28601": "iso885911",
+  "iso885913": {
+    "type": "_sbcs",
+    "chars": " ”¢£¤„¦§Ø©Ŗ«¬®Æ°±²³“µ¶·ø¹ŗ»¼½¾æĄĮĀĆÄÅĘĒČÉŹĖĢĶĪĻŠŃŅÓŌÕÖ×ŲŁŚŪÜŻŽßąįāćäåęēčéźėģķīļšńņóōõö÷ųłśūüżž’"
+  },
+  "cp28603": "iso885913",
+  "iso885914": {
+    "type": "_sbcs",
+    "chars": " Ḃḃ£ĊċḊ§Ẁ©ẂḋỲ®ŸḞḟĠġṀṁ¶ṖẁṗẃṠỳẄẅṡÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏŴÑÒÓÔÕÖṪØÙÚÛÜÝŶßàáâãäåæçèéêëìíîïŵñòóôõöṫøùúûüýŷÿ"
+  },
+  "cp28604": "iso885914",
+  "iso885915": {
+    "type": "_sbcs",
+    "chars": " ¡¢£€¥Š§š©ª«¬®¯°±²³Žµ¶·ž¹º»ŒœŸ¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "cp28605": "iso885915",
+  "iso885916": {
+    "type": "_sbcs",
+    "chars": " ĄąŁ€„Š§š©Ș«ŹźŻ°±ČłŽ”¶·žčș»ŒœŸżÀÁÂĂÄĆÆÇÈÉÊËÌÍÎÏĐŃÒÓÔŐÖŚŰÙÚÛÜĘȚßàáâăäćæçèéêëìíîïđńòóôőöśűùúûüęțÿ"
+  },
+  "cp28606": "iso885916",
+  "cp437": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£¥₧ƒáíóúñÑªº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm437": "cp437",
+  "csibm437": "cp437",
+  "cp737": {
+    "type": "_sbcs",
+    "chars": "ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩαβγδεζηθικλμνξοπρσςτυφχψ░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀ωάέήϊίόύϋώΆΈΉΊΌΎΏ±≥≤ΪΫ÷≈°∙·√ⁿ²■ "
+  },
+  "ibm737": "cp737",
+  "csibm737": "cp737",
+  "cp775": {
+    "type": "_sbcs",
+    "chars": "ĆüéāäģåćłēŖŗīŹÄÅÉæÆōöĢ¢ŚśÖÜø£Ø×¤ĀĪóŻżź”¦©®¬½¼Ł«»░▒▓│┤ĄČĘĖ╣║╗╝ĮŠ┐└┴┬├─┼ŲŪ╚╔╩╦╠═╬Žąčęėįšųūž┘┌█▄▌▐▀ÓßŌŃõÕµńĶķĻļņĒŅ’±“¾¶§÷„°∙·¹³²■ "
+  },
+  "ibm775": "cp775",
+  "csibm775": "cp775",
+  "cp850": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜø£Ø×ƒáíóúñÑªº¿®¬½¼¡«»░▒▓│┤ÁÂÀ©╣║╗╝¢¥┐└┴┬├─┼ãÃ╚╔╩╦╠═╬¤ðÐÊËÈıÍÎÏ┘┌█▄¦Ì▀ÓßÔÒõÕµþÞÚÛÙýÝ¯´±‗¾¶§÷¸°¨·¹³²■ "
+  },
+  "ibm850": "cp850",
+  "csibm850": "cp850",
+  "cp852": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäůćçłëŐőîŹÄĆÉĹĺôöĽľŚśÖÜŤťŁ×čáíóúĄąŽžĘę¬źČş«»░▒▓│┤ÁÂĚŞ╣║╗╝Żż┐└┴┬├─┼Ăă╚╔╩╦╠═╬¤đĐĎËďŇÍÎě┘┌█▄ŢŮ▀ÓßÔŃńňŠšŔÚŕŰýÝţ´˝˛ˇ˘§÷¸°¨˙űŘř■ "
+  },
+  "ibm852": "cp852",
+  "csibm852": "cp852",
+  "cp855": {
+    "type": "_sbcs",
+    "chars": "ђЂѓЃёЁєЄѕЅіІїЇјЈљЉњЊћЋќЌўЎџЏюЮъЪаАбБцЦдДеЕфФгГ«»░▒▓│┤хХиИ╣║╗╝йЙ┐└┴┬├─┼кК╚╔╩╦╠═╬¤лЛмМнНоОп┘┌█▄Пя▀ЯрРсСтТуУжЖвВьЬ№ыЫзЗшШэЭщЩчЧ§■ "
+  },
+  "ibm855": "cp855",
+  "csibm855": "cp855",
+  "cp856": {
+    "type": "_sbcs",
+    "chars": "אבגדהוזחטיךכלםמןנסעףפץצקרשת�£�×����������®¬½¼�«»░▒▓│┤���©╣║╗╝¢¥┐└┴┬├─┼��╚╔╩╦╠═╬¤���������┘┌█▄¦�▀������µ�������¯´±‗¾¶§÷¸°¨·¹³²■ "
+  },
+  "ibm856": "cp856",
+  "csibm856": "cp856",
+  "cp857": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîıÄÅÉæÆôöòûùİÖÜø£ØŞşáíóúñÑĞğ¿®¬½¼¡«»░▒▓│┤ÁÂÀ©╣║╗╝¢¥┐└┴┬├─┼ãÃ╚╔╩╦╠═╬¤ºªÊËÈ�ÍÎÏ┘┌█▄¦Ì▀ÓßÔÒõÕµ�×ÚÛÙìÿ¯´±�¾¶§÷¸°¨·¹³²■ "
+  },
+  "ibm857": "cp857",
+  "csibm857": "cp857",
+  "cp858": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜø£Ø×ƒáíóúñÑªº¿®¬½¼¡«»░▒▓│┤ÁÂÀ©╣║╗╝¢¥┐└┴┬├─┼ãÃ╚╔╩╦╠═╬¤ðÐÊËÈ€ÍÎÏ┘┌█▄¦Ì▀ÓßÔÒõÕµþÞÚÛÙýÝ¯´±‗¾¶§÷¸°¨·¹³²■ "
+  },
+  "ibm858": "cp858",
+  "csibm858": "cp858",
+  "cp860": {
+    "type": "_sbcs",
+    "chars": "ÇüéâãàÁçêÊèÍÔìÃÂÉÀÈôõòÚùÌÕÜ¢£Ù₧ÓáíóúñÑªº¿Ò¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm860": "cp860",
+  "csibm860": "cp860",
+  "cp861": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèÐðÞÄÅÉæÆôöþûÝýÖÜø£Ø₧ƒáíóúÁÍÓÚ¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm861": "cp861",
+  "csibm861": "cp861",
+  "cp862": {
+    "type": "_sbcs",
+    "chars": "אבגדהוזחטיךכלםמןנסעףפץצקרשת¢£¥₧ƒáíóúñÑªº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm862": "cp862",
+  "csibm862": "cp862",
+  "cp863": {
+    "type": "_sbcs",
+    "chars": "ÇüéâÂà¶çêëèïî‗À§ÉÈÊôËÏûù¤ÔÜ¢£ÙÛƒ¦´óú¨¸³¯Î⌐¬½¼¾«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm863": "cp863",
+  "csibm863": "cp863",
+  "cp864": {
+    "type": "_sbcs",
+    "chars": "\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f !\"#$٪&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~°·∙√▒─│┼┤┬├┴┐┌└┘β∞φ±½¼≈«»ﻷﻸ��ﻻﻼ� ﺂ£¤ﺄ��ﺎﺏﺕﺙ،ﺝﺡﺥ٠١٢٣٤٥٦٧٨٩ﻑ؛ﺱﺵﺹ؟¢ﺀﺁﺃﺅﻊﺋﺍﺑﺓﺗﺛﺟﺣﺧﺩﺫﺭﺯﺳﺷﺻﺿﻁﻅﻋﻏ¦¬÷×ﻉـﻓﻗﻛﻟﻣﻧﻫﻭﻯﻳﺽﻌﻎﻍﻡﹽّﻥﻩﻬﻰﻲﻐﻕﻵﻶﻝﻙﻱ■�"
+  },
+  "ibm864": "cp864",
+  "csibm864": "cp864",
+  "cp865": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜø£Ø₧ƒáíóúñÑªº¿⌐¬½¼¡«¤░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm865": "cp865",
+  "csibm865": "cp865",
+  "cp866": {
+    "type": "_sbcs",
+    "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмноп░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀рстуфхцчшщъыьэюяЁёЄєЇїЎў°∙·√№¤■ "
+  },
+  "ibm866": "cp866",
+  "csibm866": "cp866",
+  "cp869": {
+    "type": "_sbcs",
+    "chars": "������Ά�·¬¦‘’Έ―ΉΊΪΌ��ΎΫ©Ώ²³ά£έήίϊΐόύΑΒΓΔΕΖΗ½ΘΙ«»░▒▓│┤ΚΛΜΝ╣║╗╝ΞΟ┐└┴┬├─┼ΠΡ╚╔╩╦╠═╬ΣΤΥΦΧΨΩαβγ┘┌█▄δε▀ζηθικλμνξοπρσςτ΄±υφχ§ψ΅°¨ωϋΰώ■ "
+  },
+  "ibm869": "cp869",
+  "csibm869": "cp869",
+  "cp922": {
+    "type": "_sbcs",
+    "chars": " ¡¢£¤¥¦§¨©ª«¬®‾°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏŠÑÒÓÔÕÖ×ØÙÚÛÜÝŽßàáâãäåæçèéêëìíîïšñòóôõö÷øùúûüýžÿ"
+  },
+  "ibm922": "cp922",
+  "csibm922": "cp922",
+  "cp1046": {
+    "type": "_sbcs",
+    "chars": "ﺈ×÷ﹱ■│─┐┌└┘ﹹﹻﹽﹿﹷﺊﻰﻳﻲﻎﻏﻐﻶﻸﻺﻼ ¤ﺋﺑﺗﺛﺟﺣ،ﺧﺳ٠١٢٣٤٥٦٧٨٩ﺷ؛ﺻﺿﻊ؟ﻋءآأؤإئابةتثجحخدذرزسشصضطﻇعغﻌﺂﺄﺎﻓـفقكلمنهوىيًٌٍَُِّْﻗﻛﻟﻵﻷﻹﻻﻣﻧﻬﻩ�"
+  },
+  "ibm1046": "cp1046",
+  "csibm1046": "cp1046",
+  "cp1124": {
+    "type": "_sbcs",
+    "chars": " ЁЂҐЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя№ёђґєѕіїјљњћќ§ўџ"
+  },
+  "ibm1124": "cp1124",
+  "csibm1124": "cp1124",
+  "cp1125": {
+    "type": "_sbcs",
+    "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмноп░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀рстуфхцчшщъыьэюяЁёҐґЄєІіЇї·√№¤■ "
+  },
+  "ibm1125": "cp1125",
+  "csibm1125": "cp1125",
+  "cp1129": {
+    "type": "_sbcs",
+    "chars": " ¡¢£¤¥¦§œ©ª«¬®¯°±²³Ÿµ¶·Œ¹º»¼½¾¿ÀÁÂĂÄÅÆÇÈÉÊË̀ÍÎÏĐÑ̉ÓÔƠÖ×ØÙÚÛÜỮßàáâăäåæçèéêë́íîïđṇ̃óôơö÷øùúûüư₫ÿ"
+  },
+  "ibm1129": "cp1129",
+  "csibm1129": "cp1129",
+  "cp1133": {
+    "type": "_sbcs",
+    "chars": " ກຂຄງຈສຊຍດຕຖທນບປຜຝພຟມຢຣລວຫອຮ���ຯະາຳິີຶືຸູຼັົຽ���ເແໂໃໄ່້໊໋໌ໍໆ�ໜໝ₭����������������໐໑໒໓໔໕໖໗໘໙��¢¬¦�"
+  },
+  "ibm1133": "cp1133",
+  "csibm1133": "cp1133",
+  "cp1161": {
+    "type": "_sbcs",
+    "chars": "��������������������������������่กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู้๊๋€฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛¢¬¦ "
+  },
+  "ibm1161": "cp1161",
+  "csibm1161": "cp1161",
+  "cp1162": {
+    "type": "_sbcs",
+    "chars": "€…‘’“”•–— กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู����฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛����"
+  },
+  "ibm1162": "cp1162",
+  "csibm1162": "cp1162",
+  "cp1163": {
+    "type": "_sbcs",
+    "chars": " ¡¢£€¥¦§œ©ª«¬®¯°±²³Ÿµ¶·Œ¹º»¼½¾¿ÀÁÂĂÄÅÆÇÈÉÊË̀ÍÎÏĐÑ̉ÓÔƠÖ×ØÙÚÛÜỮßàáâăäåæçèéêë́íîïđṇ̃óôơö÷øùúûüư₫ÿ"
+  },
+  "ibm1163": "cp1163",
+  "csibm1163": "cp1163",
+  "maccroatian": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®Š™´¨≠ŽØ∞±≤≥∆µ∂∑∏š∫ªºΩžø¿¡¬√ƒ≈Ć«Č… ÀÃÕŒœĐ—“”‘’÷◊�©⁄¤‹›Æ»–·‚„‰ÂćÁčÈÍÎÏÌÓÔđÒÚÛÙıˆ˜¯πË˚¸Êæˇ"
+  },
+  "maccyrillic": {
+    "type": "_sbcs",
+    "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ†°¢£§•¶І®©™Ђђ≠Ѓѓ∞±≤≥іµ∂ЈЄєЇїЉљЊњјЅ¬√ƒ≈∆«»… ЋћЌќѕ–—“”‘’÷„ЎўЏџ№Ёёяабвгдежзийклмнопрстуфхцчшщъыьэю¤"
+  },
+  "macgreek": {
+    "type": "_sbcs",
+    "chars": "Ä¹²É³ÖÜ΅àâä΄¨çéèêë£™îï•½‰ôö¦ùûü†ΓΔΘΛΞΠß®©ΣΪ§≠°·Α±≤≥¥ΒΕΖΗΙΚΜΦΫΨΩάΝ¬ΟΡ≈Τ«»… ΥΧΆΈœ–―“”‘’÷ΉΊΌΎέήίόΏύαβψδεφγηιξκλμνοπώρστθωςχυζϊϋΐΰ�"
+  },
+  "maciceland": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûüÝ°¢£§•¶ß®©™´¨≠ÆØ∞±≤≥¥µ∂∑∏π∫ªºΩæø¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸ⁄¤ÐðÞþý·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙıˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "macroman": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®©™´¨≠ÆØ∞±≤≥¥µ∂∑∏π∫ªºΩæø¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸ⁄¤‹›ﬁﬂ‡·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙıˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "macromania": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®©™´¨≠ĂŞ∞±≤≥¥µ∂∑∏π∫ªºΩăş¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸ⁄¤‹›Ţţ‡·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙıˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "macthai": {
+    "type": "_sbcs",
+    "chars": "«»…“”�•‘’� กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู–—฿เแโใไๅๆ็่้๊๋์ํ™๏๐๑๒๓๔๕๖๗๘๙®©����"
+  },
+  "macturkish": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®©™´¨≠ÆØ∞±≤≥¥µ∂∑∏π∫ªºΩæø¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸĞğİıŞş‡·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙ�ˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "macukraine": {
+    "type": "_sbcs",
+    "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ†°Ґ£§•¶І®©™Ђђ≠Ѓѓ∞±≤≥іµґЈЄєЇїЉљЊњјЅ¬√ƒ≈∆«»… ЋћЌќѕ–—“”‘’÷„ЎўЏџ№Ёёяабвгдежзийклмнопрстуфхцчшщъыьэю¤"
+  },
+  "koi8r": {
+    "type": "_sbcs",
+    "chars": "─│┌┐└┘├┤┬┴┼▀▄█▌▐░▒▓⌠■∙√≈≤≥ ⌡°²·÷═║╒ё╓╔╕╖╗╘╙╚╛╜╝╞╟╠╡Ё╢╣╤╥╦╧╨╩╪╫╬©юабцдефгхийклмнопярстужвьызшэщчъЮАБЦДЕФГХИЙКЛМНОПЯРСТУЖВЬЫЗШЭЩЧЪ"
+  },
+  "koi8u": {
+    "type": "_sbcs",
+    "chars": "─│┌┐└┘├┤┬┴┼▀▄█▌▐░▒▓⌠■∙√≈≤≥ ⌡°²·÷═║╒ёє╔ії╗╘╙╚╛ґ╝╞╟╠╡ЁЄ╣ІЇ╦╧╨╩╪Ґ╬©юабцдефгхийклмнопярстужвьызшэщчъЮАБЦДЕФГХИЙКЛМНОПЯРСТУЖВЬЫЗШЭЩЧЪ"
+  },
+  "koi8ru": {
+    "type": "_sbcs",
+    "chars": "─│┌┐└┘├┤┬┴┼▀▄█▌▐░▒▓⌠■∙√≈≤≥ ⌡°²·÷═║╒ёє╔ії╗╘╙╚╛ґў╞╟╠╡ЁЄ╣ІЇ╦╧╨╩╪ҐЎ©юабцдефгхийклмнопярстужвьызшэщчъЮАБЦДЕФГХИЙКЛМНОПЯРСТУЖВЬЫЗШЭЩЧЪ"
+  },
+  "koi8t": {
+    "type": "_sbcs",
+    "chars": "қғ‚Ғ„…†‡�‰ҳ‹ҲҷҶ�Қ‘’“”•–—�™�›�����ӯӮё¤ӣ¦§���«¬®�°±²Ё�Ӣ¶·�№�»���©юабцдефгхийклмнопярстужвьызшэщчъЮАБЦДЕФГХИЙКЛМНОПЯРСТУЖВЬЫЗШЭЩЧЪ"
+  },
+  "armscii8": {
+    "type": "_sbcs",
+    "chars": " �և։)(»«—.՝,-֊…՜՛՞ԱաԲբԳգԴդԵեԶզԷէԸըԹթԺժԻիԼլԽխԾծԿկՀհՁձՂղՃճՄմՅյՆնՇշՈոՉչՊպՋջՌռՍսՎվՏտՐրՑցՒւՓփՔքՕօՖֆ՚�"
+  },
+  "rk1048": {
+    "type": "_sbcs",
+    "chars": "ЂЃ‚ѓ„…†‡€‰Љ‹ЊҚҺЏђ‘’“”•–—�™љ›њқһџ ҰұӘ¤Ө¦§Ё©Ғ«¬®Ү°±Ііөµ¶·ё№ғ»әҢңүАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя"
+  },
+  "tcvn": {
+    "type": "_sbcs",
+    "chars": "\u0000ÚỤ\u0003ỪỬỮ\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010ỨỰỲỶỸÝỴ\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~ÀẢÃÁẠẶẬÈẺẼÉẸỆÌỈĨÍỊÒỎÕÓỌỘỜỞỠỚỢÙỦŨ ĂÂÊÔƠƯĐăâêôơưđẶ̀̀̉̃́àảãáạẲằẳẵắẴẮẦẨẪẤỀặầẩẫấậèỂẻẽéẹềểễếệìỉỄẾỒĩíịòỔỏõóọồổỗốộờởỡớợùỖủũúụừửữứựỳỷỹýỵỐ"
+  },
+  "georgianacademy": {
+    "type": "_sbcs",
+    "chars": "‚ƒ„…†‡ˆ‰Š‹Œ‘’“”•–—˜™š›œŸ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿აბგდევზთიკლმნოპჟრსტუფქღყშჩცძწჭხჯჰჱჲჳჴჵჶçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "georgianps": {
+    "type": "_sbcs",
+    "chars": "‚ƒ„…†‡ˆ‰Š‹Œ‘’“”•–—˜™š›œŸ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿აბგდევზჱთიკლმნჲოპჟრსტჳუფქღყშჩცძწჭხჴჯჰჵæçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "pt154": {
+    "type": "_sbcs",
+    "chars": "ҖҒӮғ„…ҶҮҲүҠӢҢҚҺҸҗ‘’“”•–—ҳҷҡӣңқһҹ ЎўЈӨҘҰ§Ё©Ә«¬ӯ®Ҝ°ұІіҙө¶·ё№ә»јҪҫҝАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя"
+  },
+  "viscii": {
+    "type": "_sbcs",
+    "chars": "\u0000\u0001Ẳ\u0003\u0004ẴẪ\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010\u0011\u0012\u0013Ỷ\u0015\u0016\u0017\u0018Ỹ\u001a\u001b\u001c\u001dỴ\u001f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~ẠẮẰẶẤẦẨẬẼẸẾỀỂỄỆỐỒỔỖỘỢỚỜỞỊỎỌỈỦŨỤỲÕắằặấầẩậẽẹếềểễệốồổỗỠƠộờởịỰỨỪỬơớƯÀÁÂÃẢĂẳẵÈÉÊẺÌÍĨỳĐứÒÓÔạỷừửÙÚỹỵÝỡưàáâãảăữẫèéêẻìíĩỉđựòóôõỏọụùúũủýợỮ"
+  },
+  "iso646cn": {
+    "type": "_sbcs",
+    "chars": "\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f !\"#¥%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}‾��������������������������������������������������������������������������������������������������������������������������������"
+  },
+  "iso646jp": {
+    "type": "_sbcs",
+    "chars": "\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[¥]^_`abcdefghijklmnopqrstuvwxyz{|}‾��������������������������������������������������������������������������������������������������������������������������������"
+  },
+  "hproman8": {
+    "type": "_sbcs",
+    "chars": " ÀÂÈÊËÎÏ´ˋˆ¨˜ÙÛ₤¯Ýý°ÇçÑñ¡¿¤£¥§ƒ¢âêôûáéóúàèòùäëöüÅîØÆåíøæÄìÖÜÉïßÔÁÃãÐðÍÌÓÒÕõŠšÚŸÿÞþ·µ¶¾—¼½ªº«■»±�"
+  },
+  "macintosh": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®©™´¨≠ÆØ∞±≤≥¥µ∂∑∏π∫ªºΩæø¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸ⁄¤‹›ﬁﬂ‡·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙıˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "ascii": {
+    "type": "_sbcs",
+    "chars": "��������������������������������������������������������������������������������������������������������������������������������"
+  },
+  "tis620": {
+    "type": "_sbcs",
+    "chars": "���������������������������������กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู����฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛����"
+  }
+}
\ No newline at end of file
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/sbcs-data.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/sbcs-data.js
new file mode 100644
index 0000000..066f904
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/sbcs-data.js
@@ -0,0 +1,179 @@
+"use strict";
+
+// Manually added data to be used by sbcs codec in addition to generated one.
+
+module.exports = {
+    // Not supported by iconv, not sure why.
+    "10029": "maccenteuro",
+    "maccenteuro": {
+        "type": "_sbcs",
+        "chars": "ÄĀāÉĄÖÜáąČäčĆćéŹźĎíďĒēĖóėôöõúĚěü†°Ę£§•¶ß®©™ę¨≠ģĮįĪ≤≥īĶ∂∑łĻļĽľĹĺŅņŃ¬√ńŇ∆«»… ňŐÕőŌ–—“”‘’÷◊ōŔŕŘ‹›řŖŗŠ‚„šŚśÁŤťÍŽžŪÓÔūŮÚůŰűŲųÝýķŻŁżĢˇ"
+    },
+
+    "808": "cp808",
+    "ibm808": "cp808",
+    "cp808": {
+        "type": "_sbcs",
+        "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмноп░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀рстуфхцчшщъыьэюяЁёЄєЇїЎў°∙·√№€■ "
+    },
+
+    "mik": {
+        "type": "_sbcs",
+        "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя└┴┬├─┼╣║╚╔╩╦╠═╬┐░▒▓│┤№§╗╝┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+    },
+
+    "cp720": {
+        "type": "_sbcs",
+        "chars": "\x80\x81éâ\x84à\x86çêëèïî\x8d\x8e\x8f\x90\u0651\u0652ô¤ـûùءآأؤ£إئابةتثجحخدذرزسشص«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀ضطظعغفµقكلمنهوىي≡\u064b\u064c\u064d\u064e\u064f\u0650≈°∙·√ⁿ²■\u00a0"
+    },
+
+    // Aliases of generated encodings.
+    "ascii8bit": "ascii",
+    "usascii": "ascii",
+    "ansix34": "ascii",
+    "ansix341968": "ascii",
+    "ansix341986": "ascii",
+    "csascii": "ascii",
+    "cp367": "ascii",
+    "ibm367": "ascii",
+    "isoir6": "ascii",
+    "iso646us": "ascii",
+    "iso646irv": "ascii",
+    "us": "ascii",
+
+    "latin1": "iso88591",
+    "latin2": "iso88592",
+    "latin3": "iso88593",
+    "latin4": "iso88594",
+    "latin5": "iso88599",
+    "latin6": "iso885910",
+    "latin7": "iso885913",
+    "latin8": "iso885914",
+    "latin9": "iso885915",
+    "latin10": "iso885916",
+
+    "csisolatin1": "iso88591",
+    "csisolatin2": "iso88592",
+    "csisolatin3": "iso88593",
+    "csisolatin4": "iso88594",
+    "csisolatincyrillic": "iso88595",
+    "csisolatinarabic": "iso88596",
+    "csisolatingreek" : "iso88597",
+    "csisolatinhebrew": "iso88598",
+    "csisolatin5": "iso88599",
+    "csisolatin6": "iso885910",
+
+    "l1": "iso88591",
+    "l2": "iso88592",
+    "l3": "iso88593",
+    "l4": "iso88594",
+    "l5": "iso88599",
+    "l6": "iso885910",
+    "l7": "iso885913",
+    "l8": "iso885914",
+    "l9": "iso885915",
+    "l10": "iso885916",
+
+    "isoir14": "iso646jp",
+    "isoir57": "iso646cn",
+    "isoir100": "iso88591",
+    "isoir101": "iso88592",
+    "isoir109": "iso88593",
+    "isoir110": "iso88594",
+    "isoir144": "iso88595",
+    "isoir127": "iso88596",
+    "isoir126": "iso88597",
+    "isoir138": "iso88598",
+    "isoir148": "iso88599",
+    "isoir157": "iso885910",
+    "isoir166": "tis620",
+    "isoir179": "iso885913",
+    "isoir199": "iso885914",
+    "isoir203": "iso885915",
+    "isoir226": "iso885916",
+
+    "cp819": "iso88591",
+    "ibm819": "iso88591",
+
+    "cyrillic": "iso88595",
+
+    "arabic": "iso88596",
+    "arabic8": "iso88596",
+    "ecma114": "iso88596",
+    "asmo708": "iso88596",
+
+    "greek" : "iso88597",
+    "greek8" : "iso88597",
+    "ecma118" : "iso88597",
+    "elot928" : "iso88597",
+
+    "hebrew": "iso88598",
+    "hebrew8": "iso88598",
+
+    "turkish": "iso88599",
+    "turkish8": "iso88599",
+
+    "thai": "iso885911",
+    "thai8": "iso885911",
+
+    "celtic": "iso885914",
+    "celtic8": "iso885914",
+    "isoceltic": "iso885914",
+
+    "tis6200": "tis620",
+    "tis62025291": "tis620",
+    "tis62025330": "tis620",
+
+    "10000": "macroman",
+    "10006": "macgreek",
+    "10007": "maccyrillic",
+    "10079": "maciceland",
+    "10081": "macturkish",
+
+    "cspc8codepage437": "cp437",
+    "cspc775baltic": "cp775",
+    "cspc850multilingual": "cp850",
+    "cspcp852": "cp852",
+    "cspc862latinhebrew": "cp862",
+    "cpgr": "cp869",
+
+    "msee": "cp1250",
+    "mscyrl": "cp1251",
+    "msansi": "cp1252",
+    "msgreek": "cp1253",
+    "msturk": "cp1254",
+    "mshebr": "cp1255",
+    "msarab": "cp1256",
+    "winbaltrim": "cp1257",
+
+    "cp20866": "koi8r",
+    "20866": "koi8r",
+    "ibm878": "koi8r",
+    "cskoi8r": "koi8r",
+
+    "cp21866": "koi8u",
+    "21866": "koi8u",
+    "ibm1168": "koi8u",
+
+    "strk10482002": "rk1048",
+
+    "tcvn5712": "tcvn",
+    "tcvn57121": "tcvn",
+
+    "gb198880": "iso646cn",
+    "cn": "iso646cn",
+
+    "csiso14jisc6220ro": "iso646jp",
+    "jisc62201969ro": "iso646jp",
+    "jp": "iso646jp",
+
+    "cshproman8": "hproman8",
+    "r8": "hproman8",
+    "roman8": "hproman8",
+    "xroman8": "hproman8",
+    "ibm1051": "hproman8",
+
+    "mac": "macintosh",
+    "csmacintosh": "macintosh",
+};
+
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/big5-added.json b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/big5-added.json
new file mode 100644
index 0000000..3c3d3c2
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/big5-added.json
@@ -0,0 +1,122 @@
+[
+["8740","䏰䰲䘃䖦䕸𧉧䵷䖳𧲱䳢𧳅㮕䜶䝄䱇䱀𤊿𣘗𧍒𦺋𧃒䱗𪍑䝏䗚䲅𧱬䴇䪤䚡𦬣爥𥩔𡩣𣸆𣽡晍囻"],
+["8767","綕夝𨮹㷴霴𧯯寛𡵞媤㘥𩺰嫑宷峼杮薓𩥅瑡璝㡵𡵓𣚞𦀡㻬"],
+["87a1","𥣞㫵竼龗𤅡𨤍𣇪𠪊𣉞䌊蒄龖鐯䤰蘓墖靊鈘秐稲晠権袝瑌篅枂稬剏遆㓦珄𥶹瓆鿇垳䤯呌䄱𣚎堘穲𧭥讏䚮𦺈䆁𥶙箮𢒼鿈𢓁𢓉𢓌鿉蔄𣖻䂴鿊䓡𪷿拁灮鿋"],
+["8840","㇀",4,"𠄌㇅𠃑𠃍㇆㇇𠃋𡿨㇈𠃊㇉㇊㇋㇌𠄎㇍㇎ĀÁǍÀĒÉĚÈŌÓǑÒ࿿Ê̄Ế࿿Ê̌ỀÊāáǎàɑēéěèīíǐìōóǒòūúǔùǖǘǚ"],
+["88a1","ǜü࿿ê̄ế࿿ê̌ềêɡ⏚⏛"],
+["8940","𪎩𡅅"],
+["8943","攊"],
+["8946","丽滝鵎釟"],
+["894c","𧜵撑会伨侨兖兴农凤务动医华发变团声处备夲头学实実岚庆总斉柾栄桥济炼电纤纬纺织经统缆缷艺苏药视设询车轧轮"],
+["89a1","琑糼緍楆竉刧"],
+["89ab","醌碸酞肼"],
+["89b0","贋胶𠧧"],
+["89b5","肟黇䳍鷉鸌䰾𩷶𧀎鸊𪄳㗁"],
+["89c1","溚舾甙"],
+["89c5","䤑马骏龙禇𨑬𡷊𠗐𢫦两亁亀亇亿仫伷㑌侽㹈倃傈㑽㒓㒥円夅凛凼刅争剹劐匧㗇厩㕑厰㕓参吣㕭㕲㚁咓咣咴咹哐哯唘唣唨㖘唿㖥㖿嗗㗅"],
+["8a40","𧶄唥"],
+["8a43","𠱂𠴕𥄫喐𢳆㧬𠍁蹆𤶸𩓥䁓𨂾睺𢰸㨴䟕𨅝𦧲𤷪擝𠵼𠾴𠳕𡃴撍蹾𠺖𠰋𠽤𢲩𨉖𤓓"],
+["8a64","𠵆𩩍𨃩䟴𤺧𢳂骲㩧𩗴㿭㔆𥋇𩟔𧣈𢵄鵮頕"],
+["8a76","䏙𦂥撴哣𢵌𢯊𡁷㧻𡁯"],
+["8aa1","𦛚𦜖𧦠擪𥁒𠱃蹨𢆡𨭌𠜱"],
+["8aac","䠋𠆩㿺塳𢶍"],
+["8ab2","𤗈𠓼𦂗𠽌𠶖啹䂻䎺"],
+["8abb","䪴𢩦𡂝膪飵𠶜捹㧾𢝵跀嚡摼㹃"],
+["8ac9","𪘁𠸉𢫏𢳉"],
+["8ace","𡃈𣧂㦒㨆𨊛㕸𥹉𢃇噒𠼱𢲲𩜠㒼氽𤸻"],
+["8adf","𧕴𢺋𢈈𪙛𨳍𠹺𠰴𦠜羓𡃏𢠃𢤹㗻𥇣𠺌𠾍𠺪㾓𠼰𠵇𡅏𠹌"],
+["8af6","𠺫𠮩𠵈𡃀𡄽㿹𢚖搲𠾭"],
+["8b40","𣏴𧘹𢯎𠵾𠵿𢱑𢱕㨘𠺘𡃇𠼮𪘲𦭐𨳒𨶙𨳊閪哌苄喹"],
+["8b55","𩻃鰦骶𧝞𢷮煀腭胬尜𦕲脴㞗卟𨂽醶𠻺𠸏𠹷𠻻㗝𤷫㘉𠳖嚯𢞵𡃉𠸐𠹸𡁸𡅈𨈇𡑕𠹹𤹐𢶤婔𡀝𡀞𡃵𡃶垜𠸑"],
+["8ba1","𧚔𨋍𠾵𠹻𥅾㜃𠾶𡆀𥋘𪊽𤧚𡠺𤅷𨉼墙剨㘚𥜽箲孨䠀䬬鼧䧧鰟鮍𥭴𣄽嗻㗲嚉丨夂𡯁屮靑𠂆乛亻㔾尣彑忄㣺扌攵歺氵氺灬爫丬犭𤣩罒礻糹罓𦉪㓁"],
+["8bde","𦍋耂肀𦘒𦥑卝衤见𧢲讠贝钅镸长门𨸏韦页风飞饣𩠐鱼鸟黄歯龜丷𠂇阝户钢"],
+["8c40","倻淾𩱳龦㷉袏𤅎灷峵䬠𥇍㕙𥴰愢𨨲辧釶熑朙玺𣊁𪄇㲋𡦀䬐磤琂冮𨜏䀉橣𪊺䈣蘏𠩯稪𩥇𨫪靕灍匤𢁾鏴盙𨧣龧矝亣俰傼丯众龨吴綋墒壐𡶶庒庙忂𢜒斋"],
+["8ca1","𣏹椙橃𣱣泿"],
+["8ca7","爀𤔅玌㻛𤨓嬕璹讃𥲤𥚕窓篬糃繬苸薗龩袐龪躹龫迏蕟駠鈡龬𨶹𡐿䁱䊢娚"],
+["8cc9","顨杫䉶圽"],
+["8cce","藖𤥻芿𧄍䲁𦵴嵻𦬕𦾾龭龮宖龯曧繛湗秊㶈䓃𣉖𢞖䎚䔶"],
+["8ce6","峕𣬚諹屸㴒𣕑嵸龲煗䕘𤃬𡸣䱷㥸㑊𠆤𦱁諌侴𠈹妿腬顖𩣺弻"],
+["8d40","𠮟"],
+["8d42","𢇁𨥭䄂䚻𩁹㼇龳𪆵䃸㟖䛷𦱆䅼𨚲𧏿䕭㣔𥒚䕡䔛䶉䱻䵶䗪㿈𤬏㙡䓞䒽䇭崾嵈嵖㷼㠏嶤嶹㠠㠸幂庽弥徃㤈㤔㤿㥍惗愽峥㦉憷憹懏㦸戬抐拥挘㧸嚱"],
+["8da1","㨃揢揻搇摚㩋擀崕嘡龟㪗斆㪽旿晓㫲暒㬢朖㭂枤栀㭘桊梄㭲㭱㭻椉楃牜楤榟榅㮼槖㯝橥橴橱檂㯬檙㯲檫檵櫔櫶殁毁毪汵沪㳋洂洆洦涁㳯涤涱渕渘温溆𨧀溻滢滚齿滨滩漤漴㵆𣽁澁澾㵪㵵熷岙㶊瀬㶑灐灔灯灿炉𠌥䏁㗱𠻘"],
+["8e40","𣻗垾𦻓焾𥟠㙎榢𨯩孴穉𥣡𩓙穥穽𥦬窻窰竂竃燑𦒍䇊竚竝竪䇯咲𥰁笋筕笩𥌎𥳾箢筯莜𥮴𦱿篐萡箒箸𥴠㶭𥱥蒒篺簆簵𥳁籄粃𤢂粦晽𤕸糉糇糦籴糳糵糎"],
+["8ea1","繧䔝𦹄絝𦻖璍綉綫焵綳緒𤁗𦀩緤㴓緵𡟹緥𨍭縝𦄡𦅚繮纒䌫鑬縧罀罁罇礶𦋐駡羗𦍑羣𡙡𠁨䕜𣝦䔃𨌺翺𦒉者耈耝耨耯𪂇𦳃耻耼聡𢜔䦉𦘦𣷣𦛨朥肧𨩈脇脚墰𢛶汿𦒘𤾸擧𡒊舘𡡞橓𤩥𤪕䑺舩𠬍𦩒𣵾俹𡓽蓢荢𦬊𤦧𣔰𡝳𣷸芪椛芳䇛"],
+["8f40","蕋苐茚𠸖𡞴㛁𣅽𣕚艻苢茘𣺋𦶣𦬅𦮗𣗎㶿茝嗬莅䔋𦶥莬菁菓㑾𦻔橗蕚㒖𦹂𢻯葘𥯤葱㷓䓤檧葊𣲵祘蒨𦮖𦹷𦹃蓞萏莑䒠蒓蓤𥲑䉀𥳀䕃蔴嫲𦺙䔧蕳䔖枿蘖"],
+["8fa1","𨘥𨘻藁𧂈蘂𡖂𧃍䕫䕪蘨㙈𡢢号𧎚虾蝱𪃸蟮𢰧螱蟚蠏噡虬桖䘏衅衆𧗠𣶹𧗤衞袜䙛袴袵揁装睷𧜏覇覊覦覩覧覼𨨥觧𧤤𧪽誜瞓釾誐𧩙竩𧬺𣾏䜓𧬸煼謌謟𥐰𥕥謿譌譍誩𤩺讐讛誯𡛟䘕衏貛𧵔𧶏貫㜥𧵓賖𧶘𧶽贒贃𡤐賛灜贑𤳉㻐起"],
+["9040","趩𨀂𡀔𤦊㭼𨆼𧄌竧躭躶軃鋔輙輭𨍥𨐒辥錃𪊟𠩐辳䤪𨧞𨔽𣶻廸𣉢迹𪀔𨚼𨔁𢌥㦀𦻗逷𨔼𧪾遡𨕬𨘋邨𨜓郄𨛦邮都酧㫰醩釄粬𨤳𡺉鈎沟鉁鉢𥖹銹𨫆𣲛𨬌𥗛"],
+["90a1","𠴱錬鍫𨫡𨯫炏嫃𨫢𨫥䥥鉄𨯬𨰹𨯿鍳鑛躼閅閦鐦閠濶䊹𢙺𨛘𡉼𣸮䧟氜陻隖䅬隣𦻕懚隶磵𨫠隽双䦡𦲸𠉴𦐐𩂯𩃥𤫑𡤕𣌊霱虂霶䨏䔽䖅𤫩灵孁霛靜𩇕靗孊𩇫靟鐥僐𣂷𣂼鞉鞟鞱鞾韀韒韠𥑬韮琜𩐳響韵𩐝𧥺䫑頴頳顋顦㬎𧅵㵑𠘰𤅜"],
+["9140","𥜆飊颷飈飇䫿𦴧𡛓喰飡飦飬鍸餹𤨩䭲𩡗𩤅駵騌騻騐驘𥜥㛄𩂱𩯕髠髢𩬅髴䰎鬔鬭𨘀倴鬴𦦨㣃𣁽魐魀𩴾婅𡡣鮎𤉋鰂鯿鰌𩹨鷔𩾷𪆒𪆫𪃡𪄣𪇟鵾鶃𪄴鸎梈"],
+["91a1","鷄𢅛𪆓𪈠𡤻𪈳鴹𪂹𪊴麐麕麞麢䴴麪麯𤍤黁㭠㧥㴝伲㞾𨰫鼂鼈䮖鐤𦶢鼗鼖鼹嚟嚊齅馸𩂋韲葿齢齩竜龎爖䮾𤥵𤦻煷𤧸𤍈𤩑玞𨯚𡣺禟𨥾𨸶鍩鏳𨩄鋬鎁鏋𨥬𤒹爗㻫睲穃烐𤑳𤏸煾𡟯炣𡢾𣖙㻇𡢅𥐯𡟸㜢𡛻𡠹㛡𡝴𡣑𥽋㜣𡛀坛𤨥𡏾𡊨"],
+["9240","𡏆𡒶蔃𣚦蔃葕𤦔𧅥𣸱𥕜𣻻𧁒䓴𣛮𩦝𦼦柹㜳㰕㷧塬𡤢栐䁗𣜿𤃡𤂋𤄏𦰡哋嚞𦚱嚒𠿟𠮨𠸍鏆𨬓鎜仸儫㠙𤐶亼𠑥𠍿佋侊𥙑婨𠆫𠏋㦙𠌊𠐔㐵伩𠋀𨺳𠉵諚𠈌亘"],
+["92a1","働儍侢伃𤨎𣺊佂倮偬傁俌俥偘僼兙兛兝兞湶𣖕𣸹𣺿浲𡢄𣺉冨凃𠗠䓝𠒣𠒒𠒑赺𨪜𠜎剙劤𠡳勡鍮䙺熌𤎌𠰠𤦬𡃤槑𠸝瑹㻞璙琔瑖玘䮎𤪼𤂍叐㖄爏𤃉喴𠍅响𠯆圝鉝雴鍦埝垍坿㘾壋媙𨩆𡛺𡝯𡜐娬妸銏婾嫏娒𥥆𡧳𡡡𤊕㛵洅瑃娡𥺃"],
+["9340","媁𨯗𠐓鏠璌𡌃焅䥲鐈𨧻鎽㞠尞岞幞幈𡦖𡥼𣫮廍孏𡤃𡤄㜁𡢠㛝𡛾㛓脪𨩇𡶺𣑲𨦨弌弎𡤧𡞫婫𡜻孄蘔𧗽衠恾𢡠𢘫忛㺸𢖯𢖾𩂈𦽳懀𠀾𠁆𢘛憙憘恵𢲛𢴇𤛔𩅍"],
+["93a1","摱𤙥𢭪㨩𢬢𣑐𩣪𢹸挷𪑛撶挱揑𤧣𢵧护𢲡搻敫楲㯴𣂎𣊭𤦉𣊫唍𣋠𡣙𩐿曎𣊉𣆳㫠䆐𥖄𨬢𥖏𡛼𥕛𥐥磮𣄃𡠪𣈴㑤𣈏𣆂𤋉暎𦴤晫䮓昰𧡰𡷫晣𣋒𣋡昞𥡲㣑𣠺𣞼㮙𣞢𣏾瓐㮖枏𤘪梶栞㯄檾㡣𣟕𤒇樳橒櫉欅𡤒攑梘橌㯗橺歗𣿀𣲚鎠鋲𨯪𨫋"],
+["9440","銉𨀞𨧜鑧涥漋𤧬浧𣽿㶏渄𤀼娽渊塇洤硂焻𤌚𤉶烱牐犇犔𤞏𤜥兹𤪤𠗫瑺𣻸𣙟𤩊𤤗𥿡㼆㺱𤫟𨰣𣼵悧㻳瓌琼鎇琷䒟𦷪䕑疃㽣𤳙𤴆㽘畕癳𪗆㬙瑨𨫌𤦫𤦎㫻"],
+["94a1","㷍𤩎㻿𤧅𤣳釺圲鍂𨫣𡡤僟𥈡𥇧睸𣈲眎眏睻𤚗𣞁㩞𤣰琸璛㺿𤪺𤫇䃈𤪖𦆮錇𥖁砞碍碈磒珐祙𧝁𥛣䄎禛蒖禥樭𣻺稺秴䅮𡛦䄲鈵秱𠵌𤦌𠊙𣶺𡝮㖗啫㕰㚪𠇔𠰍竢婙𢛵𥪯𥪜娍𠉛磰娪𥯆竾䇹籝籭䈑𥮳𥺼𥺦糍𤧹𡞰粎籼粮檲緜縇緓罎𦉡"],
+["9540","𦅜𧭈綗𥺂䉪𦭵𠤖柖𠁎𣗏埄𦐒𦏸𤥢翝笧𠠬𥫩𥵃笌𥸎駦虅驣樜𣐿㧢𤧷𦖭騟𦖠蒀𧄧𦳑䓪脷䐂胆脉腂𦞴飃𦩂艢艥𦩑葓𦶧蘐𧈛媆䅿𡡀嬫𡢡嫤𡣘蚠蜨𣶏蠭𧐢娂"],
+["95a1","衮佅袇袿裦襥襍𥚃襔𧞅𧞄𨯵𨯙𨮜𨧹㺭蒣䛵䛏㟲訽訜𩑈彍鈫𤊄旔焩烄𡡅鵭貟賩𧷜妚矃姰䍮㛔踪躧𤰉輰轊䋴汘澻𢌡䢛潹溋𡟚鯩㚵𤤯邻邗啱䤆醻鐄𨩋䁢𨫼鐧𨰝𨰻蓥訫閙閧閗閖𨴴瑅㻂𤣿𤩂𤏪㻧𣈥随𨻧𨹦𨹥㻌𤧭𤩸𣿮琒瑫㻼靁𩂰"],
+["9640","桇䨝𩂓𥟟靝鍨𨦉𨰦𨬯𦎾銺嬑譩䤼珹𤈛鞛靱餸𠼦巁𨯅𤪲頟𩓚鋶𩗗釥䓀𨭐𤩧𨭤飜𨩅㼀鈪䤥萔餻饍𧬆㷽馛䭯馪驜𨭥𥣈檏騡嫾騯𩣱䮐𩥈馼䮽䮗鍽塲𡌂堢𤦸"],
+["96a1","𡓨硄𢜟𣶸棅㵽鑘㤧慐𢞁𢥫愇鱏鱓鱻鰵鰐魿鯏𩸭鮟𪇵𪃾鴡䲮𤄄鸘䲰鴌𪆴𪃭𪃳𩤯鶥蒽𦸒𦿟𦮂藼䔳𦶤𦺄𦷰萠藮𦸀𣟗𦁤秢𣖜𣙀䤭𤧞㵢鏛銾鍈𠊿碹鉷鑍俤㑀遤𥕝砽硔碶硋𡝗𣇉𤥁㚚佲濚濙瀞瀞吔𤆵垻壳垊鴖埗焴㒯𤆬燫𦱀𤾗嬨𡞵𨩉"],
+["9740","愌嫎娋䊼𤒈㜬䭻𨧼鎻鎸𡣖𠼝葲𦳀𡐓𤋺𢰦𤏁妔𣶷𦝁綨𦅛𦂤𤦹𤦋𨧺鋥珢㻩璴𨭣𡢟㻡𤪳櫘珳珻㻖𤨾𤪔𡟙𤩦𠎧𡐤𤧥瑈𤤖炥𤥶銄珦鍟𠓾錱𨫎𨨖鎆𨯧𥗕䤵𨪂煫"],
+["97a1","𤥃𠳿嚤𠘚𠯫𠲸唂秄𡟺緾𡛂𤩐𡡒䔮鐁㜊𨫀𤦭妰𡢿𡢃𧒄媡㛢𣵛㚰鉟婹𨪁𡡢鍴㳍𠪴䪖㦊僴㵩㵌𡎜煵䋻𨈘渏𩃤䓫浗𧹏灧沯㳖𣿭𣸭渂漌㵯𠏵畑㚼㓈䚀㻚䡱姄鉮䤾轁𨰜𦯀堒埈㛖𡑒烾𤍢𤩱𢿣𡊰𢎽梹楧𡎘𣓥𧯴𣛟𨪃𣟖𣏺𤲟樚𣚭𦲷萾䓟䓎"],
+["9840","𦴦𦵑𦲂𦿞漗𧄉茽𡜺菭𦲀𧁓𡟛妉媂𡞳婡婱𡤅𤇼㜭姯𡜼㛇熎鎐暚𤊥婮娫𤊓樫𣻹𧜶𤑛𤋊焝𤉙𨧡侰𦴨峂𤓎𧹍𤎽樌𤉖𡌄炦焳𤏩㶥泟勇𤩏繥姫崯㷳彜𤩝𡟟綤萦"],
+["98a1","咅𣫺𣌀𠈔坾𠣕𠘙㿥𡾞𪊶瀃𩅛嵰玏糓𨩙𩐠俈翧狍猐𧫴猸猹𥛶獁獈㺩𧬘遬燵𤣲珡臶㻊県㻑沢国琙琞琟㻢㻰㻴㻺瓓㼎㽓畂畭畲疍㽼痈痜㿀癍㿗癴㿜発𤽜熈嘣覀塩䀝睃䀹条䁅㗛瞘䁪䁯属瞾矋売砘点砜䂨砹硇硑硦葈𥔵礳栃礲䄃"],
+["9940","䄉禑禙辻稆込䅧窑䆲窼艹䇄竏竛䇏両筢筬筻簒簛䉠䉺类粜䊌粸䊔糭输烀𠳏総緔緐緽羮羴犟䎗耠耥笹耮耱联㷌垴炠肷胩䏭脌猪脎脒畠脔䐁㬹腖腙腚"],
+["99a1","䐓堺腼膄䐥膓䐭膥埯臁臤艔䒏芦艶苊苘苿䒰荗险榊萅烵葤惣蒈䔄蒾蓡蓸蔐蔸蕒䔻蕯蕰藠䕷虲蚒蚲蛯际螋䘆䘗袮裿褤襇覑𧥧訩訸誔誴豑賔賲贜䞘塟跃䟭仮踺嗘坔蹱嗵躰䠷軎転軤軭軲辷迁迊迌逳駄䢭飠鈓䤞鈨鉘鉫銱銮銿"],
+["9a40","鋣鋫鋳鋴鋽鍃鎄鎭䥅䥑麿鐗匁鐝鐭鐾䥪鑔鑹锭関䦧间阳䧥枠䨤靀䨵鞲韂噔䫤惨颹䬙飱塄餎餙冴餜餷饂饝饢䭰駅䮝騼鬏窃魩鮁鯝鯱鯴䱭鰠㝯𡯂鵉鰺"],
+["9aa1","黾噐鶓鶽鷀鷼银辶鹻麬麱麽黆铜黢黱黸竈齄𠂔𠊷𠎠椚铃妬𠓗塀铁㞹𠗕𠘕𠙶𡚺块煳𠫂𠫍𠮿呪吆𠯋咞𠯻𠰻𠱓𠱥𠱼惧𠲍噺𠲵𠳝𠳭𠵯𠶲𠷈楕鰯螥𠸄𠸎𠻗𠾐𠼭𠹳尠𠾼帋𡁜𡁏𡁶朞𡁻𡂈𡂖㙇𡂿𡃓𡄯𡄻卤蒭𡋣𡍵𡌶讁𡕷𡘙𡟃𡟇乸炻𡠭𡥪"],
+["9b40","𡨭𡩅𡰪𡱰𡲬𡻈拃𡻕𡼕熘桕𢁅槩㛈𢉼𢏗𢏺𢜪𢡱𢥏苽𢥧𢦓𢫕覥𢫨辠𢬎鞸𢬿顇骽𢱌"],
+["9b62","𢲈𢲷𥯨𢴈𢴒𢶷𢶕𢹂𢽴𢿌𣀳𣁦𣌟𣏞徱晈暿𧩹𣕧𣗳爁𤦺矗𣘚𣜖纇𠍆墵朎"],
+["9ba1","椘𣪧𧙗𥿢𣸑𣺹𧗾𢂚䣐䪸𤄙𨪚𤋮𤌍𤀻𤌴𤎖𤩅𠗊凒𠘑妟𡺨㮾𣳿𤐄𤓖垈𤙴㦛𤜯𨗨𩧉㝢𢇃譞𨭎駖𤠒𤣻𤨕爉𤫀𠱸奥𤺥𤾆𠝹軚𥀬劏圿煱𥊙𥐙𣽊𤪧喼𥑆𥑮𦭒釔㑳𥔿𧘲𥕞䜘𥕢𥕦𥟇𤤿𥡝偦㓻𣏌惞𥤃䝼𨥈𥪮𥮉𥰆𡶐垡煑澶𦄂𧰒遖𦆲𤾚譢𦐂𦑊"],
+["9c40","嵛𦯷輶𦒄𡤜諪𤧶𦒈𣿯𦔒䯀𦖿𦚵𢜛鑥𥟡憕娧晉侻嚹𤔡𦛼乪𤤴陖涏𦲽㘘襷𦞙𦡮𦐑𦡞營𦣇筂𩃀𠨑𦤦鄄𦤹穅鷰𦧺騦𦨭㙟𦑩𠀡禃𦨴𦭛崬𣔙菏𦮝䛐𦲤画补𦶮墶"],
+["9ca1","㜜𢖍𧁋𧇍㱔𧊀𧊅銁𢅺𧊋錰𧋦𤧐氹钟𧑐𠻸蠧裵𢤦𨑳𡞱溸𤨪𡠠㦤㚹尐秣䔿暶𩲭𩢤襃𧟌𧡘囖䃟𡘊㦡𣜯𨃨𡏅熭荦𧧝𩆨婧䲷𧂯𨦫𧧽𧨊𧬋𧵦𤅺筃祾𨀉澵𪋟樃𨌘厢𦸇鎿栶靝𨅯𨀣𦦵𡏭𣈯𨁈嶅𨰰𨂃圕頣𨥉嶫𤦈斾槕叒𤪥𣾁㰑朶𨂐𨃴𨄮𡾡𨅏"],
+["9d40","𨆉𨆯𨈚𨌆𨌯𨎊㗊𨑨𨚪䣺揦𨥖砈鉕𨦸䏲𨧧䏟𨧨𨭆𨯔姸𨰉輋𨿅𩃬筑𩄐𩄼㷷𩅞𤫊运犏嚋𩓧𩗩𩖰𩖸𩜲𩣑𩥉𩥪𩧃𩨨𩬎𩵚𩶛纟𩻸𩼣䲤镇𪊓熢𪋿䶑递𪗋䶜𠲜达嗁"],
+["9da1","辺𢒰边𤪓䔉繿潖檱仪㓤𨬬𧢝㜺躀𡟵𨀤𨭬𨮙𧨾𦚯㷫𧙕𣲷𥘵𥥖亚𥺁𦉘嚿𠹭踎孭𣺈𤲞揞拐𡟶𡡻攰嘭𥱊吚𥌑㷆𩶘䱽嘢嘞罉𥻘奵𣵀蝰东𠿪𠵉𣚺脗鵞贘瘻鱅癎瞹鍅吲腈苷嘥脲萘肽嗪祢噃吖𠺝㗎嘅嗱曱𨋢㘭甴嗰喺咗啲𠱁𠲖廐𥅈𠹶𢱢"],
+["9e40","𠺢麫絚嗞𡁵抝靭咔賍燶酶揼掹揾啩𢭃鱲𢺳冚㓟𠶧冧呍唞唓癦踭𦢊疱肶蠄螆裇膶萜𡃁䓬猄𤜆宐茋𦢓噻𢛴𧴯𤆣𧵳𦻐𧊶酰𡇙鈈𣳼𪚩𠺬𠻹牦𡲢䝎𤿂𧿹𠿫䃺"],
+["9ea1","鱝攟𢶠䣳𤟠𩵼𠿬𠸊恢𧖣𠿭"],
+["9ead","𦁈𡆇熣纎鵐业丄㕷嬍沲卧㚬㧜卽㚥𤘘墚𤭮舭呋垪𥪕𠥹"],
+["9ec5","㩒𢑥獴𩺬䴉鯭𣳾𩼰䱛𤾩𩖞𩿞葜𣶶𧊲𦞳𣜠挮紥𣻷𣸬㨪逈勌㹴㙺䗩𠒎癀嫰𠺶硺𧼮墧䂿噼鮋嵴癔𪐴麅䳡痹㟻愙𣃚𤏲"],
+["9ef5","噝𡊩垧𤥣𩸆刴𧂮㖭汊鵼"],
+["9f40","籖鬹埞𡝬屓擓𩓐𦌵𧅤蚭𠴨𦴢𤫢𠵱"],
+["9f4f","凾𡼏嶎霃𡷑麁遌笟鬂峑箣扨挵髿篏鬪籾鬮籂粆鰕篼鬉鼗鰛𤤾齚啳寃俽麘俲剠㸆勑坧偖妷帒韈鶫轜呩鞴饀鞺匬愰"],
+["9fa1","椬叚鰊鴂䰻陁榀傦畆𡝭駚剳"],
+["9fae","酙隁酜"],
+["9fb2","酑𨺗捿𦴣櫊嘑醎畺抅𠏼獏籰𥰡𣳽"],
+["9fc1","𤤙盖鮝个𠳔莾衂"],
+["9fc9","届槀僭坺刟巵从氱𠇲伹咜哚劚趂㗾弌㗳"],
+["9fdb","歒酼龥鮗頮颴骺麨麄煺笔"],
+["9fe7","毺蠘罸"],
+["9feb","嘠𪙊蹷齓"],
+["9ff0","跔蹏鸜踁抂𨍽踨蹵竓𤩷稾磘泪詧瘇"],
+["a040","𨩚鼦泎蟖痃𪊲硓咢贌狢獱謭猂瓱賫𤪻蘯徺袠䒷"],
+["a055","𡠻𦸅"],
+["a058","詾𢔛"],
+["a05b","惽癧髗鵄鍮鮏蟵"],
+["a063","蠏賷猬霡鮰㗖犲䰇籑饊𦅙慙䰄麖慽"],
+["a073","坟慯抦戹拎㩜懢厪𣏵捤栂㗒"],
+["a0a1","嵗𨯂迚𨸹"],
+["a0a6","僙𡵆礆匲阸𠼻䁥"],
+["a0ae","矾"],
+["a0b0","糂𥼚糚稭聦聣絍甅瓲覔舚朌聢𧒆聛瓰脃眤覉𦟌畓𦻑螩蟎臈螌詉貭譃眫瓸蓚㘵榲趦"],
+["a0d4","覩瑨涹蟁𤀑瓧㷛煶悤憜㳑煢恷"],
+["a0e2","罱𨬭牐惩䭾删㰘𣳇𥻗𧙖𥔱𡥄𡋾𩤃𦷜𧂭峁𦆭𨨏𣙷𠃮𦡆𤼎䕢嬟𦍌齐麦𦉫"],
+["a3c0","␀",31,"␡"],
+["c6a1","①",9,"⑴",9,"ⅰ",9,"丶丿亅亠冂冖冫勹匸卩厶夊宀巛⼳广廴彐彡攴无疒癶辵隶¨ˆヽヾゝゞ〃仝々〆〇ー［］✽ぁ",23],
+["c740","す",58,"ァアィイ"],
+["c7a1","ゥ",81,"А",5,"ЁЖ",4],
+["c840","Л",26,"ёж",25,"⇧↸↹㇏𠃌乚𠂊刂䒑"],
+["c8a1","龰冈龱𧘇"],
+["c8cd","￢￤＇＂㈱№℡゛゜⺀⺄⺆⺇⺈⺊⺌⺍⺕⺜⺝⺥⺧⺪⺬⺮⺶⺼⺾⻆⻊⻌⻍⻏⻖⻗⻞⻣"],
+["c8f5","ʃɐɛɔɵœøŋʊɪ"],
+["f9fe","￭"],
+["fa40","𠕇鋛𠗟𣿅蕌䊵珯况㙉𤥂𨧤鍄𡧛苮𣳈砼杄拟𤤳𨦪𠊠𦮳𡌅侫𢓭倈𦴩𧪄𣘀𤪱𢔓倩𠍾徤𠎀𠍇滛𠐟偽儁㑺儎顬㝃萖𤦤𠒇兠𣎴兪𠯿𢃼𠋥𢔰𠖎𣈳𡦃宂蝽𠖳𣲙冲冸"],
+["faa1","鴴凉减凑㳜凓𤪦决凢卂凭菍椾𣜭彻刋刦刼劵剗劔効勅簕蕂勠蘍𦬓包𨫞啉滙𣾀𠥔𣿬匳卄𠯢泋𡜦栛珕恊㺪㣌𡛨燝䒢卭却𨚫卾卿𡖖𡘓矦厓𨪛厠厫厮玧𥝲㽙玜叁叅汉义埾叙㪫𠮏叠𣿫𢶣叶𠱷吓灹唫晗浛呭𦭓𠵴啝咏咤䞦𡜍𠻝㶴𠵍"],
+["fb40","𨦼𢚘啇䳭启琗喆喩嘅𡣗𤀺䕒𤐵暳𡂴嘷曍𣊊暤暭噍噏磱囱鞇叾圀囯园𨭦㘣𡉏坆𤆥汮炋坂㚱𦱾埦𡐖堃𡑔𤍣堦𤯵塜墪㕡壠壜𡈼壻寿坃𪅐𤉸鏓㖡够梦㛃湙"],
+["fba1","𡘾娤啓𡚒蔅姉𠵎𦲁𦴪𡟜姙𡟻𡞲𦶦浱𡠨𡛕姹𦹅媫婣㛦𤦩婷㜈媖瑥嫓𦾡𢕔㶅𡤑㜲𡚸広勐孶斈孼𧨎䀄䡝𠈄寕慠𡨴𥧌𠖥寳宝䴐尅𡭄尓珎尔𡲥𦬨屉䣝岅峩峯嶋𡷹𡸷崐崘嵆𡺤岺巗苼㠭𤤁𢁉𢅳芇㠶㯂帮檊幵幺𤒼𠳓厦亷廐厨𡝱帉廴𨒂"],
+["fc40","廹廻㢠廼栾鐛弍𠇁弢㫞䢮𡌺强𦢈𢏐彘𢑱彣鞽𦹮彲鍀𨨶徧嶶㵟𥉐𡽪𧃸𢙨釖𠊞𨨩怱暅𡡷㥣㷇㘹垐𢞴祱㹀悞悤悳𤦂𤦏𧩓璤僡媠慤萤慂慈𦻒憁凴𠙖憇宪𣾷"],
+["fca1","𢡟懓𨮝𩥝懐㤲𢦀𢣁怣慜攞掋𠄘担𡝰拕𢸍捬𤧟㨗搸揸𡎎𡟼撐澊𢸶頔𤂌𥜝擡擥鑻㩦携㩗敍漖𤨨𤨣斅敭敟𣁾斵𤥀䬷旑䃘𡠩无旣忟𣐀昘𣇷𣇸晄𣆤𣆥晋𠹵晧𥇦晳晴𡸽𣈱𨗴𣇈𥌓矅𢣷馤朂𤎜𤨡㬫槺𣟂杞杧杢𤇍𩃭柗䓩栢湐鈼栁𣏦𦶠桝"],
+["fd40","𣑯槡樋𨫟楳棃𣗍椁椀㴲㨁𣘼㮀枬楡𨩊䋼椶榘㮡𠏉荣傐槹𣙙𢄪橅𣜃檝㯳枱櫈𩆜㰍欝𠤣惞欵歴𢟍溵𣫛𠎵𡥘㝀吡𣭚毡𣻼毜氷𢒋𤣱𦭑汚舦汹𣶼䓅𣶽𤆤𤤌𤤀"],
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diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/cp936.json b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/cp936.json
new file mode 100644
index 0000000..49ddb9a
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/cp936.json
@@ -0,0 +1,264 @@
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+["fe40","兀嗀﨎﨏﨑﨓﨔礼﨟蘒﨡﨣﨤﨧﨨﨩"]
+]
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/cp949.json b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/cp949.json
new file mode 100644
index 0000000..2022a00
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/cp949.json
@@ -0,0 +1,273 @@
+[
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+["b481","큱큲큳큵",6,"큾큿킀킂",18,"뇟뇨뇩뇬뇰뇹뇻뇽누눅눈눋눌눔눕눗눙눠눴눼뉘뉜뉠뉨뉩뉴뉵뉼늄늅늉느늑는늘늙늚늠늡늣능늦늪늬늰늴니닉닌닐닒님닙닛닝닢다닥닦단닫",4,"닳담답닷",4,"닿대댁댄댈댐댑댓댔댕댜더덕덖던덛덜덞덟덤덥"],
+["b541","킕",14,"킦킧킩킪킫킭",5],
+["b561","킳킶킸킺",5,"탂탃탅탆탇탊",5,"탒탖",4],
+["b581","탛탞탟탡탢탣탥",6,"탮탲",5,"탹",11,"덧덩덫덮데덱덴델뎀뎁뎃뎄뎅뎌뎐뎔뎠뎡뎨뎬도독돈돋돌돎돐돔돕돗동돛돝돠돤돨돼됐되된될됨됩됫됴두둑둔둘둠둡둣둥둬뒀뒈뒝뒤뒨뒬뒵뒷뒹듀듄듈듐듕드득든듣들듦듬듭듯등듸디딕딘딛딜딤딥딧딨딩딪따딱딴딸"],
+["b641","턅",7,"턎",17],
+["b661","턠",15,"턲턳턵턶턷턹턻턼턽턾"],
+["b681","턿텂텆",5,"텎텏텑텒텓텕",6,"텞텠텢",5,"텩텪텫텭땀땁땃땄땅땋때땍땐땔땜땝땟땠땡떠떡떤떨떪떫떰떱떳떴떵떻떼떽뗀뗄뗌뗍뗏뗐뗑뗘뗬또똑똔똘똥똬똴뙈뙤뙨뚜뚝뚠뚤뚫뚬뚱뛔뛰뛴뛸뜀뜁뜅뜨뜩뜬뜯뜰뜸뜹뜻띄띈띌띔띕띠띤띨띰띱띳띵라락란랄람랍랏랐랑랒랖랗"],
+["b741","텮",13,"텽",6,"톅톆톇톉톊"],
+["b761","톋",20,"톢톣톥톦톧"],
+["b781","톩",6,"톲톴톶톷톸톹톻톽톾톿퇁",14,"래랙랜랠램랩랫랬랭랴략랸럇량러럭런럴럼럽럿렀렁렇레렉렌렐렘렙렛렝려력련렬렴렵렷렸령례롄롑롓로록론롤롬롭롯롱롸롼뢍뢨뢰뢴뢸룀룁룃룅료룐룔룝룟룡루룩룬룰룸룹룻룽뤄뤘뤠뤼뤽륀륄륌륏륑류륙륜률륨륩"],
+["b841","퇐",7,"퇙",17],
+["b861","퇫",8,"퇵퇶퇷퇹",13],
+["b881","툈툊",5,"툑",24,"륫륭르륵른를름릅릇릉릊릍릎리릭린릴림립릿링마막만많",4,"맘맙맛망맞맡맣매맥맨맬맴맵맷맸맹맺먀먁먈먕머먹먼멀멂멈멉멋멍멎멓메멕멘멜멤멥멧멨멩며멱면멸몃몄명몇몌모목몫몬몰몲몸몹못몽뫄뫈뫘뫙뫼"],
+["b941","툪툫툮툯툱툲툳툵",6,"툾퉀퉂",5,"퉉퉊퉋퉌"],
+["b961","퉍",14,"퉝",6,"퉥퉦퉧퉨"],
+["b981","퉩",22,"튂튃튅튆튇튉튊튋튌묀묄묍묏묑묘묜묠묩묫무묵묶문묻물묽묾뭄뭅뭇뭉뭍뭏뭐뭔뭘뭡뭣뭬뮈뮌뮐뮤뮨뮬뮴뮷므믄믈믐믓미믹민믿밀밂밈밉밋밌밍및밑바",4,"받",4,"밤밥밧방밭배백밴밸뱀뱁뱃뱄뱅뱉뱌뱍뱐뱝버벅번벋벌벎범법벗"],
+["ba41","튍튎튏튒튓튔튖",5,"튝튞튟튡튢튣튥",6,"튭"],
+["ba61","튮튯튰튲",5,"튺튻튽튾틁틃",4,"틊틌",5],
+["ba81","틒틓틕틖틗틙틚틛틝",6,"틦",9,"틲틳틵틶틷틹틺벙벚베벡벤벧벨벰벱벳벴벵벼벽변별볍볏볐병볕볘볜보복볶본볼봄봅봇봉봐봔봤봬뵀뵈뵉뵌뵐뵘뵙뵤뵨부북분붇불붉붊붐붑붓붕붙붚붜붤붰붸뷔뷕뷘뷜뷩뷰뷴뷸븀븃븅브븍븐블븜븝븟비빅빈빌빎빔빕빗빙빚빛빠빡빤"],
+["bb41","틻",4,"팂팄팆",5,"팏팑팒팓팕팗",4,"팞팢팣"],
+["bb61","팤팦팧팪팫팭팮팯팱",6,"팺팾",5,"퍆퍇퍈퍉"],
+["bb81","퍊",31,"빨빪빰빱빳빴빵빻빼빽뺀뺄뺌뺍뺏뺐뺑뺘뺙뺨뻐뻑뻔뻗뻘뻠뻣뻤뻥뻬뼁뼈뼉뼘뼙뼛뼜뼝뽀뽁뽄뽈뽐뽑뽕뾔뾰뿅뿌뿍뿐뿔뿜뿟뿡쀼쁑쁘쁜쁠쁨쁩삐삑삔삘삠삡삣삥사삭삯산삳살삵삶삼삽삿샀상샅새색샌샐샘샙샛샜생샤"],
+["bc41","퍪",17,"퍾퍿펁펂펃펅펆펇"],
+["bc61","펈펉펊펋펎펒",5,"펚펛펝펞펟펡",6,"펪펬펮"],
+["bc81","펯",4,"펵펶펷펹펺펻펽",6,"폆폇폊",5,"폑",5,"샥샨샬샴샵샷샹섀섄섈섐섕서",4,"섣설섦섧섬섭섯섰성섶세섹센셀셈셉셋셌셍셔셕션셜셤셥셧셨셩셰셴셸솅소속솎손솔솖솜솝솟송솥솨솩솬솰솽쇄쇈쇌쇔쇗쇘쇠쇤쇨쇰쇱쇳쇼쇽숀숄숌숍숏숑수숙순숟술숨숩숫숭"],
+["bd41","폗폙",7,"폢폤",7,"폮폯폱폲폳폵폶폷"],
+["bd61","폸폹폺폻폾퐀퐂",5,"퐉",13],
+["bd81","퐗",5,"퐞",25,"숯숱숲숴쉈쉐쉑쉔쉘쉠쉥쉬쉭쉰쉴쉼쉽쉿슁슈슉슐슘슛슝스슥슨슬슭슴습슷승시식신싣실싫심십싯싱싶싸싹싻싼쌀쌈쌉쌌쌍쌓쌔쌕쌘쌜쌤쌥쌨쌩썅써썩썬썰썲썸썹썼썽쎄쎈쎌쏀쏘쏙쏜쏟쏠쏢쏨쏩쏭쏴쏵쏸쐈쐐쐤쐬쐰"],
+["be41","퐸",7,"푁푂푃푅",14],
+["be61","푔",7,"푝푞푟푡푢푣푥",7,"푮푰푱푲"],
+["be81","푳",4,"푺푻푽푾풁풃",4,"풊풌풎",5,"풕",8,"쐴쐼쐽쑈쑤쑥쑨쑬쑴쑵쑹쒀쒔쒜쒸쒼쓩쓰쓱쓴쓸쓺쓿씀씁씌씐씔씜씨씩씬씰씸씹씻씽아악안앉않알앍앎앓암압앗았앙앝앞애액앤앨앰앱앳앴앵야약얀얄얇얌얍얏양얕얗얘얜얠얩어억언얹얻얼얽얾엄",6,"엌엎"],
+["bf41","풞",10,"풪",14],
+["bf61","풹",18,"퓍퓎퓏퓑퓒퓓퓕"],
+["bf81","퓖",5,"퓝퓞퓠",7,"퓩퓪퓫퓭퓮퓯퓱",6,"퓹퓺퓼에엑엔엘엠엡엣엥여역엮연열엶엷염",5,"옅옆옇예옌옐옘옙옛옜오옥온올옭옮옰옳옴옵옷옹옻와왁완왈왐왑왓왔왕왜왝왠왬왯왱외왹왼욀욈욉욋욍요욕욘욜욤욥욧용우욱운울욹욺움웁웃웅워웍원월웜웝웠웡웨"],
+["c041","퓾",5,"픅픆픇픉픊픋픍",6,"픖픘",5],
+["c061","픞",25],
+["c081","픸픹픺픻픾픿핁핂핃핅",6,"핎핐핒",5,"핚핛핝핞핟핡핢핣웩웬웰웸웹웽위윅윈윌윔윕윗윙유육윤율윰윱윳융윷으윽은을읊음읍읏응",7,"읜읠읨읫이익인일읽읾잃임입잇있잉잊잎자작잔잖잗잘잚잠잡잣잤장잦재잭잰잴잼잽잿쟀쟁쟈쟉쟌쟎쟐쟘쟝쟤쟨쟬저적전절젊"],
+["c141","핤핦핧핪핬핮",5,"핶핷핹핺핻핽",6,"햆햊햋"],
+["c161","햌햍햎햏햑",19,"햦햧"],
+["c181","햨",31,"점접젓정젖제젝젠젤젬젭젯젱져젼졀졈졉졌졍졔조족존졸졺좀좁좃종좆좇좋좌좍좔좝좟좡좨좼좽죄죈죌죔죕죗죙죠죡죤죵주죽준줄줅줆줌줍줏중줘줬줴쥐쥑쥔쥘쥠쥡쥣쥬쥰쥴쥼즈즉즌즐즘즙즛증지직진짇질짊짐집짓"],
+["c241","헊헋헍헎헏헑헓",4,"헚헜헞",5,"헦헧헩헪헫헭헮"],
+["c261","헯",4,"헶헸헺",5,"혂혃혅혆혇혉",6,"혒"],
+["c281","혖",5,"혝혞혟혡혢혣혥",7,"혮",9,"혺혻징짖짙짚짜짝짠짢짤짧짬짭짯짰짱째짹짼쨀쨈쨉쨋쨌쨍쨔쨘쨩쩌쩍쩐쩔쩜쩝쩟쩠쩡쩨쩽쪄쪘쪼쪽쫀쫄쫌쫍쫏쫑쫓쫘쫙쫠쫬쫴쬈쬐쬔쬘쬠쬡쭁쭈쭉쭌쭐쭘쭙쭝쭤쭸쭹쮜쮸쯔쯤쯧쯩찌찍찐찔찜찝찡찢찧차착찬찮찰참찹찻"],
+["c341","혽혾혿홁홂홃홄홆홇홊홌홎홏홐홒홓홖홗홙홚홛홝",4],
+["c361","홢",4,"홨홪",5,"홲홳홵",11],
+["c381","횁횂횄횆",5,"횎횏횑횒횓횕",7,"횞횠횢",5,"횩횪찼창찾채책챈챌챔챕챗챘챙챠챤챦챨챰챵처척천철첨첩첫첬청체첵첸첼쳄쳅쳇쳉쳐쳔쳤쳬쳰촁초촉촌촐촘촙촛총촤촨촬촹최쵠쵤쵬쵭쵯쵱쵸춈추축춘출춤춥춧충춰췄췌췐취췬췰췸췹췻췽츄츈츌츔츙츠측츤츨츰츱츳층"],
+["c441","횫횭횮횯횱",7,"횺횼",7,"훆훇훉훊훋"],
+["c461","훍훎훏훐훒훓훕훖훘훚",5,"훡훢훣훥훦훧훩",4],
+["c481","훮훯훱훲훳훴훶",5,"훾훿휁휂휃휅",11,"휒휓휔치칙친칟칠칡침칩칫칭카칵칸칼캄캅캇캉캐캑캔캘캠캡캣캤캥캬캭컁커컥컨컫컬컴컵컷컸컹케켁켄켈켐켑켓켕켜켠켤켬켭켯켰켱켸코콕콘콜콤콥콧콩콰콱콴콸쾀쾅쾌쾡쾨쾰쿄쿠쿡쿤쿨쿰쿱쿳쿵쿼퀀퀄퀑퀘퀭퀴퀵퀸퀼"],
+["c541","휕휖휗휚휛휝휞휟휡",6,"휪휬휮",5,"휶휷휹"],
+["c561","휺휻휽",6,"흅흆흈흊",5,"흒흓흕흚",4],
+["c581","흟흢흤흦흧흨흪흫흭흮흯흱흲흳흵",6,"흾흿힀힂",5,"힊힋큄큅큇큉큐큔큘큠크큭큰클큼큽킁키킥킨킬킴킵킷킹타탁탄탈탉탐탑탓탔탕태택탠탤탬탭탯탰탱탸턍터턱턴털턺텀텁텃텄텅테텍텐텔템텝텟텡텨텬텼톄톈토톡톤톨톰톱톳통톺톼퇀퇘퇴퇸툇툉툐투툭툰툴툼툽툿퉁퉈퉜"],
+["c641","힍힎힏힑",6,"힚힜힞",5],
+["c6a1","퉤튀튁튄튈튐튑튕튜튠튤튬튱트특튼튿틀틂틈틉틋틔틘틜틤틥티틱틴틸팀팁팃팅파팍팎판팔팖팜팝팟팠팡팥패팩팬팰팸팹팻팼팽퍄퍅퍼퍽펀펄펌펍펏펐펑페펙펜펠펨펩펫펭펴편펼폄폅폈평폐폘폡폣포폭폰폴폼폽폿퐁"],
+["c7a1","퐈퐝푀푄표푠푤푭푯푸푹푼푿풀풂품풉풋풍풔풩퓌퓐퓔퓜퓟퓨퓬퓰퓸퓻퓽프픈플픔픕픗피픽핀필핌핍핏핑하학한할핥함합핫항해핵핸핼햄햅햇했행햐향허헉헌헐헒험헙헛헝헤헥헨헬헴헵헷헹혀혁현혈혐협혓혔형혜혠"],
+["c8a1","혤혭호혹혼홀홅홈홉홋홍홑화확환활홧황홰홱홴횃횅회획횐횔횝횟횡효횬횰횹횻후훅훈훌훑훔훗훙훠훤훨훰훵훼훽휀휄휑휘휙휜휠휨휩휫휭휴휵휸휼흄흇흉흐흑흔흖흗흘흙흠흡흣흥흩희흰흴흼흽힁히힉힌힐힘힙힛힝"],
+["caa1","伽佳假價加可呵哥嘉嫁家暇架枷柯歌珂痂稼苛茄街袈訶賈跏軻迦駕刻却各恪慤殼珏脚覺角閣侃刊墾奸姦干幹懇揀杆柬桿澗癎看磵稈竿簡肝艮艱諫間乫喝曷渴碣竭葛褐蝎鞨勘坎堪嵌感憾戡敢柑橄減甘疳監瞰紺邯鑑鑒龕"],
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+["e2a1","戍手授搜收數樹殊水洙漱燧狩獸琇璲瘦睡秀穗竪粹綏綬繡羞脩茱蒐蓚藪袖誰讐輸遂邃酬銖銹隋隧隨雖需須首髓鬚叔塾夙孰宿淑潚熟琡璹肅菽巡徇循恂旬栒楯橓殉洵淳珣盾瞬筍純脣舜荀蓴蕣詢諄醇錞順馴戌術述鉥崇崧"],
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+["e6a1","旅歟汝濾璵礖礪與艅茹輿轝閭餘驪麗黎亦力域役易曆歷疫繹譯轢逆驛嚥堧姸娟宴年延憐戀捐挻撚椽沇沿涎涓淵演漣烟然煙煉燃燕璉硏硯秊筵緣練縯聯衍軟輦蓮連鉛鍊鳶列劣咽悅涅烈熱裂說閱厭廉念捻染殮炎焰琰艶苒"],
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diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/cp950.json b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/cp950.json
new file mode 100644
index 0000000..d8bc871
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/cp950.json
@@ -0,0 +1,177 @@
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+["daa1","琚琡琭琱琤琣琝琩琠琲瓻甯畯畬痧痚痡痦痝痟痤痗皕皒盚睆睇睄睍睅睊睎睋睌矞矬硠硤硥硜硭硱硪确硰硩硨硞硢祴祳祲祰稂稊稃稌稄窙竦竤筊笻筄筈筌筎筀筘筅粢粞粨粡絘絯絣絓絖絧絪絏絭絜絫絒絔絩絑絟絎缾缿罥"],
+["db40","罦羢羠羡翗聑聏聐胾胔腃腊腒腏腇脽腍脺臦臮臷臸臹舄舼舽舿艵茻菏菹萣菀菨萒菧菤菼菶萐菆菈菫菣莿萁菝菥菘菿菡菋菎菖菵菉萉萏菞萑萆菂菳"],
+["dba1","菕菺菇菑菪萓菃菬菮菄菻菗菢萛菛菾蛘蛢蛦蛓蛣蛚蛪蛝蛫蛜蛬蛩蛗蛨蛑衈衖衕袺裗袹袸裀袾袶袼袷袽袲褁裉覕覘覗觝觚觛詎詍訹詙詀詗詘詄詅詒詈詑詊詌詏豟貁貀貺貾貰貹貵趄趀趉跘跓跍跇跖跜跏跕跙跈跗跅軯軷軺"],
+["dc40","軹軦軮軥軵軧軨軶軫軱軬軴軩逭逴逯鄆鄬鄄郿郼鄈郹郻鄁鄀鄇鄅鄃酡酤酟酢酠鈁鈊鈥鈃鈚鈦鈏鈌鈀鈒釿釽鈆鈄鈧鈂鈜鈤鈙鈗鈅鈖镻閍閌閐隇陾隈"],
+["dca1","隉隃隀雂雈雃雱雰靬靰靮頇颩飫鳦黹亃亄亶傽傿僆傮僄僊傴僈僂傰僁傺傱僋僉傶傸凗剺剸剻剼嗃嗛嗌嗐嗋嗊嗝嗀嗔嗄嗩喿嗒喍嗏嗕嗢嗖嗈嗲嗍嗙嗂圔塓塨塤塏塍塉塯塕塎塝塙塥塛堽塣塱壼嫇嫄嫋媺媸媱媵媰媿嫈媻嫆"],
+["dd40","媷嫀嫊媴媶嫍媹媐寖寘寙尟尳嵱嵣嵊嵥嵲嵬嵞嵨嵧嵢巰幏幎幊幍幋廅廌廆廋廇彀徯徭惷慉慊愫慅愶愲愮慆愯慏愩慀戠酨戣戥戤揅揱揫搐搒搉搠搤"],
+["dda1","搳摃搟搕搘搹搷搢搣搌搦搰搨摁搵搯搊搚摀搥搧搋揧搛搮搡搎敯斒旓暆暌暕暐暋暊暙暔晸朠楦楟椸楎楢楱椿楅楪椹楂楗楙楺楈楉椵楬椳椽楥棰楸椴楩楀楯楄楶楘楁楴楌椻楋椷楜楏楑椲楒椯楻椼歆歅歃歂歈歁殛嗀毻毼"],
+["de40","毹毷毸溛滖滈溏滀溟溓溔溠溱溹滆滒溽滁溞滉溷溰滍溦滏溲溾滃滜滘溙溒溎溍溤溡溿溳滐滊溗溮溣煇煔煒煣煠煁煝煢煲煸煪煡煂煘煃煋煰煟煐煓"],
+["dea1","煄煍煚牏犍犌犑犐犎猼獂猻猺獀獊獉瑄瑊瑋瑒瑑瑗瑀瑏瑐瑎瑂瑆瑍瑔瓡瓿瓾瓽甝畹畷榃痯瘏瘃痷痾痼痹痸瘐痻痶痭痵痽皙皵盝睕睟睠睒睖睚睩睧睔睙睭矠碇碚碔碏碄碕碅碆碡碃硹碙碀碖硻祼禂祽祹稑稘稙稒稗稕稢稓"],
+["df40","稛稐窣窢窞竫筦筤筭筴筩筲筥筳筱筰筡筸筶筣粲粴粯綈綆綀綍絿綅絺綎絻綃絼綌綔綄絽綒罭罫罧罨罬羦羥羧翛翜耡腤腠腷腜腩腛腢腲朡腞腶腧腯"],
+["dfa1","腄腡舝艉艄艀艂艅蓱萿葖葶葹蒏蒍葥葑葀蒆葧萰葍葽葚葙葴葳葝蔇葞萷萺萴葺葃葸萲葅萩菙葋萯葂萭葟葰萹葎葌葒葯蓅蒎萻葇萶萳葨葾葄萫葠葔葮葐蜋蜄蛷蜌蛺蛖蛵蝍蛸蜎蜉蜁蛶蜍蜅裖裋裍裎裞裛裚裌裐覅覛觟觥觤"],
+["e040","觡觠觢觜触詶誆詿詡訿詷誂誄詵誃誁詴詺谼豋豊豥豤豦貆貄貅賌赨赩趑趌趎趏趍趓趔趐趒跰跠跬跱跮跐跩跣跢跧跲跫跴輆軿輁輀輅輇輈輂輋遒逿"],
+["e0a1","遄遉逽鄐鄍鄏鄑鄖鄔鄋鄎酮酯鉈鉒鈰鈺鉦鈳鉥鉞銃鈮鉊鉆鉭鉬鉏鉠鉧鉯鈶鉡鉰鈱鉔鉣鉐鉲鉎鉓鉌鉖鈲閟閜閞閛隒隓隑隗雎雺雽雸雵靳靷靸靲頏頍頎颬飶飹馯馲馰馵骭骫魛鳪鳭鳧麀黽僦僔僗僨僳僛僪僝僤僓僬僰僯僣僠"],
+["e140","凘劀劁勩勫匰厬嘧嘕嘌嘒嗼嘏嘜嘁嘓嘂嗺嘝嘄嗿嗹墉塼墐墘墆墁塿塴墋塺墇墑墎塶墂墈塻墔墏壾奫嫜嫮嫥嫕嫪嫚嫭嫫嫳嫢嫠嫛嫬嫞嫝嫙嫨嫟孷寠"],
+["e1a1","寣屣嶂嶀嵽嶆嵺嶁嵷嶊嶉嶈嵾嵼嶍嵹嵿幘幙幓廘廑廗廎廜廕廙廒廔彄彃彯徶愬愨慁慞慱慳慒慓慲慬憀慴慔慺慛慥愻慪慡慖戩戧戫搫摍摛摝摴摶摲摳摽摵摦撦摎撂摞摜摋摓摠摐摿搿摬摫摙摥摷敳斠暡暠暟朅朄朢榱榶槉"],
+["e240","榠槎榖榰榬榼榑榙榎榧榍榩榾榯榿槄榽榤槔榹槊榚槏榳榓榪榡榞槙榗榐槂榵榥槆歊歍歋殞殟殠毃毄毾滎滵滱漃漥滸漷滻漮漉潎漙漚漧漘漻漒滭漊"],
+["e2a1","漶潳滹滮漭潀漰漼漵滫漇漎潃漅滽滶漹漜滼漺漟漍漞漈漡熇熐熉熀熅熂熏煻熆熁熗牄牓犗犕犓獃獍獑獌瑢瑳瑱瑵瑲瑧瑮甀甂甃畽疐瘖瘈瘌瘕瘑瘊瘔皸瞁睼瞅瞂睮瞀睯睾瞃碲碪碴碭碨硾碫碞碥碠碬碢碤禘禊禋禖禕禔禓"],
+["e340","禗禈禒禐稫穊稰稯稨稦窨窫窬竮箈箜箊箑箐箖箍箌箛箎箅箘劄箙箤箂粻粿粼粺綧綷緂綣綪緁緀緅綝緎緄緆緋緌綯綹綖綼綟綦綮綩綡緉罳翢翣翥翞"],
+["e3a1","耤聝聜膉膆膃膇膍膌膋舕蒗蒤蒡蒟蒺蓎蓂蒬蒮蒫蒹蒴蓁蓍蒪蒚蒱蓐蒝蒧蒻蒢蒔蓇蓌蒛蒩蒯蒨蓖蒘蒶蓏蒠蓗蓔蓒蓛蒰蒑虡蜳蜣蜨蝫蝀蜮蜞蜡蜙蜛蝃蜬蝁蜾蝆蜠蜲蜪蜭蜼蜒蜺蜱蜵蝂蜦蜧蜸蜤蜚蜰蜑裷裧裱裲裺裾裮裼裶裻"],
+["e440","裰裬裫覝覡覟覞觩觫觨誫誙誋誒誏誖谽豨豩賕賏賗趖踉踂跿踍跽踊踃踇踆踅跾踀踄輐輑輎輍鄣鄜鄠鄢鄟鄝鄚鄤鄡鄛酺酲酹酳銥銤鉶銛鉺銠銔銪銍"],
+["e4a1","銦銚銫鉹銗鉿銣鋮銎銂銕銢鉽銈銡銊銆銌銙銧鉾銇銩銝銋鈭隞隡雿靘靽靺靾鞃鞀鞂靻鞄鞁靿韎韍頖颭颮餂餀餇馝馜駃馹馻馺駂馽駇骱髣髧鬾鬿魠魡魟鳱鳲鳵麧僿儃儰僸儆儇僶僾儋儌僽儊劋劌勱勯噈噂噌嘵噁噊噉噆噘"],
+["e540","噚噀嘳嘽嘬嘾嘸嘪嘺圚墫墝墱墠墣墯墬墥墡壿嫿嫴嫽嫷嫶嬃嫸嬂嫹嬁嬇嬅嬏屧嶙嶗嶟嶒嶢嶓嶕嶠嶜嶡嶚嶞幩幝幠幜緳廛廞廡彉徲憋憃慹憱憰憢憉"],
+["e5a1","憛憓憯憭憟憒憪憡憍慦憳戭摮摰撖撠撅撗撜撏撋撊撌撣撟摨撱撘敶敺敹敻斲斳暵暰暩暲暷暪暯樀樆樗槥槸樕槱槤樠槿槬槢樛樝槾樧槲槮樔槷槧橀樈槦槻樍槼槫樉樄樘樥樏槶樦樇槴樖歑殥殣殢殦氁氀毿氂潁漦潾澇濆澒"],
+["e640","澍澉澌潢潏澅潚澖潶潬澂潕潲潒潐潗澔澓潝漀潡潫潽潧澐潓澋潩潿澕潣潷潪潻熲熯熛熰熠熚熩熵熝熥熞熤熡熪熜熧熳犘犚獘獒獞獟獠獝獛獡獚獙"],
+["e6a1","獢璇璉璊璆璁瑽璅璈瑼瑹甈甇畾瘥瘞瘙瘝瘜瘣瘚瘨瘛皜皝皞皛瞍瞏瞉瞈磍碻磏磌磑磎磔磈磃磄磉禚禡禠禜禢禛歶稹窲窴窳箷篋箾箬篎箯箹篊箵糅糈糌糋緷緛緪緧緗緡縃緺緦緶緱緰緮緟罶羬羰羭翭翫翪翬翦翨聤聧膣膟"],
+["e740","膞膕膢膙膗舖艏艓艒艐艎艑蔤蔻蔏蔀蔩蔎蔉蔍蔟蔊蔧蔜蓻蔫蓺蔈蔌蓴蔪蓲蔕蓷蓫蓳蓼蔒蓪蓩蔖蓾蔨蔝蔮蔂蓽蔞蓶蔱蔦蓧蓨蓰蓯蓹蔘蔠蔰蔋蔙蔯虢"],
+["e7a1","蝖蝣蝤蝷蟡蝳蝘蝔蝛蝒蝡蝚蝑蝞蝭蝪蝐蝎蝟蝝蝯蝬蝺蝮蝜蝥蝏蝻蝵蝢蝧蝩衚褅褌褔褋褗褘褙褆褖褑褎褉覢覤覣觭觰觬諏諆誸諓諑諔諕誻諗誾諀諅諘諃誺誽諙谾豍貏賥賟賙賨賚賝賧趠趜趡趛踠踣踥踤踮踕踛踖踑踙踦踧"],
+["e840","踔踒踘踓踜踗踚輬輤輘輚輠輣輖輗遳遰遯遧遫鄯鄫鄩鄪鄲鄦鄮醅醆醊醁醂醄醀鋐鋃鋄鋀鋙銶鋏鋱鋟鋘鋩鋗鋝鋌鋯鋂鋨鋊鋈鋎鋦鋍鋕鋉鋠鋞鋧鋑鋓"],
+["e8a1","銵鋡鋆銴镼閬閫閮閰隤隢雓霅霈霂靚鞊鞎鞈韐韏頞頝頦頩頨頠頛頧颲餈飺餑餔餖餗餕駜駍駏駓駔駎駉駖駘駋駗駌骳髬髫髳髲髱魆魃魧魴魱魦魶魵魰魨魤魬鳼鳺鳽鳿鳷鴇鴀鳹鳻鴈鴅鴄麃黓鼏鼐儜儓儗儚儑凞匴叡噰噠噮"],
+["e940","噳噦噣噭噲噞噷圜圛壈墽壉墿墺壂墼壆嬗嬙嬛嬡嬔嬓嬐嬖嬨嬚嬠嬞寯嶬嶱嶩嶧嶵嶰嶮嶪嶨嶲嶭嶯嶴幧幨幦幯廩廧廦廨廥彋徼憝憨憖懅憴懆懁懌憺"],
+["e9a1","憿憸憌擗擖擐擏擉撽撉擃擛擳擙攳敿敼斢曈暾曀曊曋曏暽暻暺曌朣樴橦橉橧樲橨樾橝橭橶橛橑樨橚樻樿橁橪橤橐橏橔橯橩橠樼橞橖橕橍橎橆歕歔歖殧殪殫毈毇氄氃氆澭濋澣濇澼濎濈潞濄澽澞濊澨瀄澥澮澺澬澪濏澿澸"],
+["ea40","澢濉澫濍澯澲澰燅燂熿熸燖燀燁燋燔燊燇燏熽燘熼燆燚燛犝犞獩獦獧獬獥獫獪瑿璚璠璔璒璕璡甋疀瘯瘭瘱瘽瘳瘼瘵瘲瘰皻盦瞚瞝瞡瞜瞛瞢瞣瞕瞙"],
+["eaa1","瞗磝磩磥磪磞磣磛磡磢磭磟磠禤穄穈穇窶窸窵窱窷篞篣篧篝篕篥篚篨篹篔篪篢篜篫篘篟糒糔糗糐糑縒縡縗縌縟縠縓縎縜縕縚縢縋縏縖縍縔縥縤罃罻罼罺羱翯耪耩聬膱膦膮膹膵膫膰膬膴膲膷膧臲艕艖艗蕖蕅蕫蕍蕓蕡蕘"],
+["eb40","蕀蕆蕤蕁蕢蕄蕑蕇蕣蔾蕛蕱蕎蕮蕵蕕蕧蕠薌蕦蕝蕔蕥蕬虣虥虤螛螏螗螓螒螈螁螖螘蝹螇螣螅螐螑螝螄螔螜螚螉褞褦褰褭褮褧褱褢褩褣褯褬褟觱諠"],
+["eba1","諢諲諴諵諝謔諤諟諰諈諞諡諨諿諯諻貑貒貐賵賮賱賰賳赬赮趥趧踳踾踸蹀蹅踶踼踽蹁踰踿躽輶輮輵輲輹輷輴遶遹遻邆郺鄳鄵鄶醓醐醑醍醏錧錞錈錟錆錏鍺錸錼錛錣錒錁鍆錭錎錍鋋錝鋺錥錓鋹鋷錴錂錤鋿錩錹錵錪錔錌"],
+["ec40","錋鋾錉錀鋻錖閼闍閾閹閺閶閿閵閽隩雔霋霒霐鞙鞗鞔韰韸頵頯頲餤餟餧餩馞駮駬駥駤駰駣駪駩駧骹骿骴骻髶髺髹髷鬳鮀鮅鮇魼魾魻鮂鮓鮒鮐魺鮕"],
+["eca1","魽鮈鴥鴗鴠鴞鴔鴩鴝鴘鴢鴐鴙鴟麈麆麇麮麭黕黖黺鼒鼽儦儥儢儤儠儩勴嚓嚌嚍嚆嚄嚃噾嚂噿嚁壖壔壏壒嬭嬥嬲嬣嬬嬧嬦嬯嬮孻寱寲嶷幬幪徾徻懃憵憼懧懠懥懤懨懞擯擩擣擫擤擨斁斀斶旚曒檍檖檁檥檉檟檛檡檞檇檓檎"],
+["ed40","檕檃檨檤檑橿檦檚檅檌檒歛殭氉濌澩濴濔濣濜濭濧濦濞濲濝濢濨燡燱燨燲燤燰燢獳獮獯璗璲璫璐璪璭璱璥璯甐甑甒甏疄癃癈癉癇皤盩瞵瞫瞲瞷瞶"],
+["eda1","瞴瞱瞨矰磳磽礂磻磼磲礅磹磾礄禫禨穜穛穖穘穔穚窾竀竁簅簏篲簀篿篻簎篴簋篳簂簉簃簁篸篽簆篰篱簐簊糨縭縼繂縳顈縸縪繉繀繇縩繌縰縻縶繄縺罅罿罾罽翴翲耬膻臄臌臊臅臇膼臩艛艚艜薃薀薏薧薕薠薋薣蕻薤薚薞"],
+["ee40","蕷蕼薉薡蕺蕸蕗薎薖薆薍薙薝薁薢薂薈薅蕹蕶薘薐薟虨螾螪螭蟅螰螬螹螵螼螮蟉蟃蟂蟌螷螯蟄蟊螴螶螿螸螽蟞螲褵褳褼褾襁襒褷襂覭覯覮觲觳謞"],
+["eea1","謘謖謑謅謋謢謏謒謕謇謍謈謆謜謓謚豏豰豲豱豯貕貔賹赯蹎蹍蹓蹐蹌蹇轃轀邅遾鄸醚醢醛醙醟醡醝醠鎡鎃鎯鍤鍖鍇鍼鍘鍜鍶鍉鍐鍑鍠鍭鎏鍌鍪鍹鍗鍕鍒鍏鍱鍷鍻鍡鍞鍣鍧鎀鍎鍙闇闀闉闃闅閷隮隰隬霠霟霘霝霙鞚鞡鞜"],
+["ef40","鞞鞝韕韔韱顁顄顊顉顅顃餥餫餬餪餳餲餯餭餱餰馘馣馡騂駺駴駷駹駸駶駻駽駾駼騃骾髾髽鬁髼魈鮚鮨鮞鮛鮦鮡鮥鮤鮆鮢鮠鮯鴳鵁鵧鴶鴮鴯鴱鴸鴰"],
+["efa1","鵅鵂鵃鴾鴷鵀鴽翵鴭麊麉麍麰黈黚黻黿鼤鼣鼢齔龠儱儭儮嚘嚜嚗嚚嚝嚙奰嬼屩屪巀幭幮懘懟懭懮懱懪懰懫懖懩擿攄擽擸攁攃擼斔旛曚曛曘櫅檹檽櫡櫆檺檶檷櫇檴檭歞毉氋瀇瀌瀍瀁瀅瀔瀎濿瀀濻瀦濼濷瀊爁燿燹爃燽獶"],
+["f040","璸瓀璵瓁璾璶璻瓂甔甓癜癤癙癐癓癗癚皦皽盬矂瞺磿礌礓礔礉礐礒礑禭禬穟簜簩簙簠簟簭簝簦簨簢簥簰繜繐繖繣繘繢繟繑繠繗繓羵羳翷翸聵臑臒"],
+["f0a1","臐艟艞薴藆藀藃藂薳薵薽藇藄薿藋藎藈藅薱薶藒蘤薸薷薾虩蟧蟦蟢蟛蟫蟪蟥蟟蟳蟤蟔蟜蟓蟭蟘蟣螤蟗蟙蠁蟴蟨蟝襓襋襏襌襆襐襑襉謪謧謣謳謰謵譇謯謼謾謱謥謷謦謶謮謤謻謽謺豂豵貙貘貗賾贄贂贀蹜蹢蹠蹗蹖蹞蹥蹧"],
+["f140","蹛蹚蹡蹝蹩蹔轆轇轈轋鄨鄺鄻鄾醨醥醧醯醪鎵鎌鎒鎷鎛鎝鎉鎧鎎鎪鎞鎦鎕鎈鎙鎟鎍鎱鎑鎲鎤鎨鎴鎣鎥闒闓闑隳雗雚巂雟雘雝霣霢霥鞬鞮鞨鞫鞤鞪"],
+["f1a1","鞢鞥韗韙韖韘韺顐顑顒颸饁餼餺騏騋騉騍騄騑騊騅騇騆髀髜鬈鬄鬅鬩鬵魊魌魋鯇鯆鯃鮿鯁鮵鮸鯓鮶鯄鮹鮽鵜鵓鵏鵊鵛鵋鵙鵖鵌鵗鵒鵔鵟鵘鵚麎麌黟鼁鼀鼖鼥鼫鼪鼩鼨齌齕儴儵劖勷厴嚫嚭嚦嚧嚪嚬壚壝壛夒嬽嬾嬿巃幰"],
+["f240","徿懻攇攐攍攉攌攎斄旞旝曞櫧櫠櫌櫑櫙櫋櫟櫜櫐櫫櫏櫍櫞歠殰氌瀙瀧瀠瀖瀫瀡瀢瀣瀩瀗瀤瀜瀪爌爊爇爂爅犥犦犤犣犡瓋瓅璷瓃甖癠矉矊矄矱礝礛"],
+["f2a1","礡礜礗礞禰穧穨簳簼簹簬簻糬糪繶繵繸繰繷繯繺繲繴繨罋罊羃羆羷翽翾聸臗臕艤艡艣藫藱藭藙藡藨藚藗藬藲藸藘藟藣藜藑藰藦藯藞藢蠀蟺蠃蟶蟷蠉蠌蠋蠆蟼蠈蟿蠊蠂襢襚襛襗襡襜襘襝襙覈覷覶觶譐譈譊譀譓譖譔譋譕"],
+["f340","譑譂譒譗豃豷豶貚贆贇贉趬趪趭趫蹭蹸蹳蹪蹯蹻軂轒轑轏轐轓辴酀鄿醰醭鏞鏇鏏鏂鏚鏐鏹鏬鏌鏙鎩鏦鏊鏔鏮鏣鏕鏄鏎鏀鏒鏧镽闚闛雡霩霫霬霨霦"],
+["f3a1","鞳鞷鞶韝韞韟顜顙顝顗颿颽颻颾饈饇饃馦馧騚騕騥騝騤騛騢騠騧騣騞騜騔髂鬋鬊鬎鬌鬷鯪鯫鯠鯞鯤鯦鯢鯰鯔鯗鯬鯜鯙鯥鯕鯡鯚鵷鶁鶊鶄鶈鵱鶀鵸鶆鶋鶌鵽鵫鵴鵵鵰鵩鶅鵳鵻鶂鵯鵹鵿鶇鵨麔麑黀黼鼭齀齁齍齖齗齘匷嚲"],
+["f440","嚵嚳壣孅巆巇廮廯忀忁懹攗攖攕攓旟曨曣曤櫳櫰櫪櫨櫹櫱櫮櫯瀼瀵瀯瀷瀴瀱灂瀸瀿瀺瀹灀瀻瀳灁爓爔犨獽獼璺皫皪皾盭矌矎矏矍矲礥礣礧礨礤礩"],
+["f4a1","禲穮穬穭竷籉籈籊籇籅糮繻繾纁纀羺翿聹臛臙舋艨艩蘢藿蘁藾蘛蘀藶蘄蘉蘅蘌藽蠙蠐蠑蠗蠓蠖襣襦覹觷譠譪譝譨譣譥譧譭趮躆躈躄轙轖轗轕轘轚邍酃酁醷醵醲醳鐋鐓鏻鐠鐏鐔鏾鐕鐐鐨鐙鐍鏵鐀鏷鐇鐎鐖鐒鏺鐉鏸鐊鏿"],
+["f540","鏼鐌鏶鐑鐆闞闠闟霮霯鞹鞻韽韾顠顢顣顟飁飂饐饎饙饌饋饓騲騴騱騬騪騶騩騮騸騭髇髊髆鬐鬒鬑鰋鰈鯷鰅鰒鯸鱀鰇鰎鰆鰗鰔鰉鶟鶙鶤鶝鶒鶘鶐鶛"],
+["f5a1","鶠鶔鶜鶪鶗鶡鶚鶢鶨鶞鶣鶿鶩鶖鶦鶧麙麛麚黥黤黧黦鼰鼮齛齠齞齝齙龑儺儹劘劗囃嚽嚾孈孇巋巏廱懽攛欂櫼欃櫸欀灃灄灊灈灉灅灆爝爚爙獾甗癪矐礭礱礯籔籓糲纊纇纈纋纆纍罍羻耰臝蘘蘪蘦蘟蘣蘜蘙蘧蘮蘡蘠蘩蘞蘥"],
+["f640","蠩蠝蠛蠠蠤蠜蠫衊襭襩襮襫觺譹譸譅譺譻贐贔趯躎躌轞轛轝酆酄酅醹鐿鐻鐶鐩鐽鐼鐰鐹鐪鐷鐬鑀鐱闥闤闣霵霺鞿韡顤飉飆飀饘饖騹騽驆驄驂驁騺"],
+["f6a1","騿髍鬕鬗鬘鬖鬺魒鰫鰝鰜鰬鰣鰨鰩鰤鰡鶷鶶鶼鷁鷇鷊鷏鶾鷅鷃鶻鶵鷎鶹鶺鶬鷈鶱鶭鷌鶳鷍鶲鹺麜黫黮黭鼛鼘鼚鼱齎齥齤龒亹囆囅囋奱孋孌巕巑廲攡攠攦攢欋欈欉氍灕灖灗灒爞爟犩獿瓘瓕瓙瓗癭皭礵禴穰穱籗籜籙籛籚"],
+["f740","糴糱纑罏羇臞艫蘴蘵蘳蘬蘲蘶蠬蠨蠦蠪蠥襱覿覾觻譾讄讂讆讅譿贕躕躔躚躒躐躖躗轠轢酇鑌鑐鑊鑋鑏鑇鑅鑈鑉鑆霿韣顪顩飋饔饛驎驓驔驌驏驈驊"],
+["f7a1","驉驒驐髐鬙鬫鬻魖魕鱆鱈鰿鱄鰹鰳鱁鰼鰷鰴鰲鰽鰶鷛鷒鷞鷚鷋鷐鷜鷑鷟鷩鷙鷘鷖鷵鷕鷝麶黰鼵鼳鼲齂齫龕龢儽劙壨壧奲孍巘蠯彏戁戃戄攩攥斖曫欑欒欏毊灛灚爢玂玁玃癰矔籧籦纕艬蘺虀蘹蘼蘱蘻蘾蠰蠲蠮蠳襶襴襳觾"],
+["f840","讌讎讋讈豅贙躘轤轣醼鑢鑕鑝鑗鑞韄韅頀驖驙鬞鬟鬠鱒鱘鱐鱊鱍鱋鱕鱙鱌鱎鷻鷷鷯鷣鷫鷸鷤鷶鷡鷮鷦鷲鷰鷢鷬鷴鷳鷨鷭黂黐黲黳鼆鼜鼸鼷鼶齃齏"],
+["f8a1","齱齰齮齯囓囍孎屭攭曭曮欓灟灡灝灠爣瓛瓥矕礸禷禶籪纗羉艭虃蠸蠷蠵衋讔讕躞躟躠躝醾醽釂鑫鑨鑩雥靆靃靇韇韥驞髕魙鱣鱧鱦鱢鱞鱠鸂鷾鸇鸃鸆鸅鸀鸁鸉鷿鷽鸄麠鼞齆齴齵齶囔攮斸欘欙欗欚灢爦犪矘矙礹籩籫糶纚"],
+["f940","纘纛纙臠臡虆虇虈襹襺襼襻觿讘讙躥躤躣鑮鑭鑯鑱鑳靉顲饟鱨鱮鱭鸋鸍鸐鸏鸒鸑麡黵鼉齇齸齻齺齹圞灦籯蠼趲躦釃鑴鑸鑶鑵驠鱴鱳鱱鱵鸔鸓黶鼊"],
+["f9a1","龤灨灥糷虪蠾蠽蠿讞貜躩軉靋顳顴飌饡馫驤驦驧鬤鸕鸗齈戇欞爧虌躨钂钀钁驩驨鬮鸙爩虋讟钃鱹麷癵驫鱺鸝灩灪麤齾齉龘碁銹裏墻恒粧嫺╔╦╗╠╬╣╚╩╝╒╤╕╞╪╡╘╧╛╓╥╖╟╫╢╙╨╜║═╭╮╰╯▓"]
+]
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/eucjp.json b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/eucjp.json
new file mode 100644
index 0000000..4fa61ca
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/eucjp.json
@@ -0,0 +1,182 @@
+[
+["0","\u0000",127],
+["8ea1","｡",62],
+["a1a1","　、。，．・：；？！゛゜´｀¨＾￣＿ヽヾゝゞ〃仝々〆〇ー―‐／＼～∥｜…‥‘’“”（）〔〕［］｛｝〈",9,"＋－±×÷＝≠＜＞≦≧∞∴♂♀°′″℃￥＄￠￡％＃＆＊＠§☆★○●◎◇"],
+["a2a1","◆□■△▲▽▼※〒→←↑↓〓"],
+["a2ba","∈∋⊆⊇⊂⊃∪∩"],
+["a2ca","∧∨￢⇒⇔∀∃"],
+["a2dc","∠⊥⌒∂∇≡≒≪≫√∽∝∵∫∬"],
+["a2f2","Å‰♯♭♪†‡¶"],
+["a2fe","◯"],
+["a3b0","０",9],
+["a3c1","Ａ",25],
+["a3e1","ａ",25],
+["a4a1","ぁ",82],
+["a5a1","ァ",85],
+["a6a1","Α",16,"Σ",6],
+["a6c1","α",16,"σ",6],
+["a7a1","А",5,"ЁЖ",25],
+["a7d1","а",5,"ёж",25],
+["a8a1","─│┌┐┘└├┬┤┴┼━┃┏┓┛┗┣┳┫┻╋┠┯┨┷┿┝┰┥┸╂"],
+["ada1","①",19,"Ⅰ",9],
+["adc0","㍉㌔㌢㍍㌘㌧㌃㌶㍑㍗㌍㌦㌣㌫㍊㌻㎜㎝㎞㎎㎏㏄㎡"],
+["addf","㍻〝〟№㏍℡㊤",4,"㈱㈲㈹㍾㍽㍼≒≡∫∮∑√⊥∠∟⊿∵∩∪"],
+["b0a1","亜唖娃阿哀愛挨姶逢葵茜穐悪握渥旭葦芦鯵梓圧斡扱宛姐虻飴絢綾鮎或粟袷安庵按暗案闇鞍杏以伊位依偉囲夷委威尉惟意慰易椅為畏異移維緯胃萎衣謂違遺医井亥域育郁磯一壱溢逸稲茨芋鰯允印咽員因姻引飲淫胤蔭"],
+["b1a1","院陰隠韻吋右宇烏羽迂雨卯鵜窺丑碓臼渦嘘唄欝蔚鰻姥厩浦瓜閏噂云運雲荏餌叡営嬰影映曳栄永泳洩瑛盈穎頴英衛詠鋭液疫益駅悦謁越閲榎厭円園堰奄宴延怨掩援沿演炎焔煙燕猿縁艶苑薗遠鉛鴛塩於汚甥凹央奥往応"],
+["b2a1","押旺横欧殴王翁襖鴬鴎黄岡沖荻億屋憶臆桶牡乙俺卸恩温穏音下化仮何伽価佳加可嘉夏嫁家寡科暇果架歌河火珂禍禾稼箇花苛茄荷華菓蝦課嘩貨迦過霞蚊俄峨我牙画臥芽蛾賀雅餓駕介会解回塊壊廻快怪悔恢懐戒拐改"],
+["b3a1","魁晦械海灰界皆絵芥蟹開階貝凱劾外咳害崖慨概涯碍蓋街該鎧骸浬馨蛙垣柿蛎鈎劃嚇各廓拡撹格核殻獲確穫覚角赫較郭閣隔革学岳楽額顎掛笠樫橿梶鰍潟割喝恰括活渇滑葛褐轄且鰹叶椛樺鞄株兜竃蒲釜鎌噛鴨栢茅萱"],
+["b4a1","粥刈苅瓦乾侃冠寒刊勘勧巻喚堪姦完官寛干幹患感慣憾換敢柑桓棺款歓汗漢澗潅環甘監看竿管簡緩缶翰肝艦莞観諌貫還鑑間閑関陥韓館舘丸含岸巌玩癌眼岩翫贋雁頑顔願企伎危喜器基奇嬉寄岐希幾忌揮机旗既期棋棄"],
+["b5a1","機帰毅気汽畿祈季稀紀徽規記貴起軌輝飢騎鬼亀偽儀妓宜戯技擬欺犠疑祇義蟻誼議掬菊鞠吉吃喫桔橘詰砧杵黍却客脚虐逆丘久仇休及吸宮弓急救朽求汲泣灸球究窮笈級糾給旧牛去居巨拒拠挙渠虚許距鋸漁禦魚亨享京"],
+["b6a1","供侠僑兇競共凶協匡卿叫喬境峡強彊怯恐恭挟教橋況狂狭矯胸脅興蕎郷鏡響饗驚仰凝尭暁業局曲極玉桐粁僅勤均巾錦斤欣欽琴禁禽筋緊芹菌衿襟謹近金吟銀九倶句区狗玖矩苦躯駆駈駒具愚虞喰空偶寓遇隅串櫛釧屑屈"],
+["b7a1","掘窟沓靴轡窪熊隈粂栗繰桑鍬勲君薫訓群軍郡卦袈祁係傾刑兄啓圭珪型契形径恵慶慧憩掲携敬景桂渓畦稽系経継繋罫茎荊蛍計詣警軽頚鶏芸迎鯨劇戟撃激隙桁傑欠決潔穴結血訣月件倹倦健兼券剣喧圏堅嫌建憲懸拳捲"],
+["b8a1","検権牽犬献研硯絹県肩見謙賢軒遣鍵険顕験鹸元原厳幻弦減源玄現絃舷言諺限乎個古呼固姑孤己庫弧戸故枯湖狐糊袴股胡菰虎誇跨鈷雇顧鼓五互伍午呉吾娯後御悟梧檎瑚碁語誤護醐乞鯉交佼侯候倖光公功効勾厚口向"],
+["b9a1","后喉坑垢好孔孝宏工巧巷幸広庚康弘恒慌抗拘控攻昂晃更杭校梗構江洪浩港溝甲皇硬稿糠紅紘絞綱耕考肯肱腔膏航荒行衡講貢購郊酵鉱砿鋼閤降項香高鴻剛劫号合壕拷濠豪轟麹克刻告国穀酷鵠黒獄漉腰甑忽惚骨狛込"],
+["baa1","此頃今困坤墾婚恨懇昏昆根梱混痕紺艮魂些佐叉唆嵯左差査沙瑳砂詐鎖裟坐座挫債催再最哉塞妻宰彩才採栽歳済災采犀砕砦祭斎細菜裁載際剤在材罪財冴坂阪堺榊肴咲崎埼碕鷺作削咋搾昨朔柵窄策索錯桜鮭笹匙冊刷"],
+["bba1","察拶撮擦札殺薩雑皐鯖捌錆鮫皿晒三傘参山惨撒散桟燦珊産算纂蚕讃賛酸餐斬暫残仕仔伺使刺司史嗣四士始姉姿子屍市師志思指支孜斯施旨枝止死氏獅祉私糸紙紫肢脂至視詞詩試誌諮資賜雌飼歯事似侍児字寺慈持時"],
+["bca1","次滋治爾璽痔磁示而耳自蒔辞汐鹿式識鴫竺軸宍雫七叱執失嫉室悉湿漆疾質実蔀篠偲柴芝屡蕊縞舎写射捨赦斜煮社紗者謝車遮蛇邪借勺尺杓灼爵酌釈錫若寂弱惹主取守手朱殊狩珠種腫趣酒首儒受呪寿授樹綬需囚収周"],
+["bda1","宗就州修愁拾洲秀秋終繍習臭舟蒐衆襲讐蹴輯週酋酬集醜什住充十従戎柔汁渋獣縦重銃叔夙宿淑祝縮粛塾熟出術述俊峻春瞬竣舜駿准循旬楯殉淳準潤盾純巡遵醇順処初所暑曙渚庶緒署書薯藷諸助叙女序徐恕鋤除傷償"],
+["bea1","勝匠升召哨商唱嘗奨妾娼宵将小少尚庄床廠彰承抄招掌捷昇昌昭晶松梢樟樵沼消渉湘焼焦照症省硝礁祥称章笑粧紹肖菖蒋蕉衝裳訟証詔詳象賞醤鉦鍾鐘障鞘上丈丞乗冗剰城場壌嬢常情擾条杖浄状畳穣蒸譲醸錠嘱埴飾"],
+["bfa1","拭植殖燭織職色触食蝕辱尻伸信侵唇娠寝審心慎振新晋森榛浸深申疹真神秦紳臣芯薪親診身辛進針震人仁刃塵壬尋甚尽腎訊迅陣靭笥諏須酢図厨逗吹垂帥推水炊睡粋翠衰遂酔錐錘随瑞髄崇嵩数枢趨雛据杉椙菅頗雀裾"],
+["c0a1","澄摺寸世瀬畝是凄制勢姓征性成政整星晴棲栖正清牲生盛精聖声製西誠誓請逝醒青静斉税脆隻席惜戚斥昔析石積籍績脊責赤跡蹟碩切拙接摂折設窃節説雪絶舌蝉仙先千占宣専尖川戦扇撰栓栴泉浅洗染潜煎煽旋穿箭線"],
+["c1a1","繊羨腺舛船薦詮賎践選遷銭銑閃鮮前善漸然全禅繕膳糎噌塑岨措曾曽楚狙疏疎礎祖租粗素組蘇訴阻遡鼠僧創双叢倉喪壮奏爽宋層匝惣想捜掃挿掻操早曹巣槍槽漕燥争痩相窓糟総綜聡草荘葬蒼藻装走送遭鎗霜騒像増憎"],
+["c2a1","臓蔵贈造促側則即息捉束測足速俗属賊族続卒袖其揃存孫尊損村遜他多太汰詑唾堕妥惰打柁舵楕陀駄騨体堆対耐岱帯待怠態戴替泰滞胎腿苔袋貸退逮隊黛鯛代台大第醍題鷹滝瀧卓啄宅托択拓沢濯琢託鐸濁諾茸凧蛸只"],
+["c3a1","叩但達辰奪脱巽竪辿棚谷狸鱈樽誰丹単嘆坦担探旦歎淡湛炭短端箪綻耽胆蛋誕鍛団壇弾断暖檀段男談値知地弛恥智池痴稚置致蜘遅馳築畜竹筑蓄逐秩窒茶嫡着中仲宙忠抽昼柱注虫衷註酎鋳駐樗瀦猪苧著貯丁兆凋喋寵"],
+["c4a1","帖帳庁弔張彫徴懲挑暢朝潮牒町眺聴脹腸蝶調諜超跳銚長頂鳥勅捗直朕沈珍賃鎮陳津墜椎槌追鎚痛通塚栂掴槻佃漬柘辻蔦綴鍔椿潰坪壷嬬紬爪吊釣鶴亭低停偵剃貞呈堤定帝底庭廷弟悌抵挺提梯汀碇禎程締艇訂諦蹄逓"],
+["c5a1","邸鄭釘鼎泥摘擢敵滴的笛適鏑溺哲徹撤轍迭鉄典填天展店添纏甜貼転顛点伝殿澱田電兎吐堵塗妬屠徒斗杜渡登菟賭途都鍍砥砺努度土奴怒倒党冬凍刀唐塔塘套宕島嶋悼投搭東桃梼棟盗淘湯涛灯燈当痘祷等答筒糖統到"],
+["c6a1","董蕩藤討謄豆踏逃透鐙陶頭騰闘働動同堂導憧撞洞瞳童胴萄道銅峠鴇匿得徳涜特督禿篤毒独読栃橡凸突椴届鳶苫寅酉瀞噸屯惇敦沌豚遁頓呑曇鈍奈那内乍凪薙謎灘捺鍋楢馴縄畷南楠軟難汝二尼弐迩匂賑肉虹廿日乳入"],
+["c7a1","如尿韮任妊忍認濡禰祢寧葱猫熱年念捻撚燃粘乃廼之埜嚢悩濃納能脳膿農覗蚤巴把播覇杷波派琶破婆罵芭馬俳廃拝排敗杯盃牌背肺輩配倍培媒梅楳煤狽買売賠陪這蝿秤矧萩伯剥博拍柏泊白箔粕舶薄迫曝漠爆縛莫駁麦"],
+["c8a1","函箱硲箸肇筈櫨幡肌畑畠八鉢溌発醗髪伐罰抜筏閥鳩噺塙蛤隼伴判半反叛帆搬斑板氾汎版犯班畔繁般藩販範釆煩頒飯挽晩番盤磐蕃蛮匪卑否妃庇彼悲扉批披斐比泌疲皮碑秘緋罷肥被誹費避非飛樋簸備尾微枇毘琵眉美"],
+["c9a1","鼻柊稗匹疋髭彦膝菱肘弼必畢筆逼桧姫媛紐百謬俵彪標氷漂瓢票表評豹廟描病秒苗錨鋲蒜蛭鰭品彬斌浜瀕貧賓頻敏瓶不付埠夫婦富冨布府怖扶敷斧普浮父符腐膚芙譜負賦赴阜附侮撫武舞葡蕪部封楓風葺蕗伏副復幅服"],
+["caa1","福腹複覆淵弗払沸仏物鮒分吻噴墳憤扮焚奮粉糞紛雰文聞丙併兵塀幣平弊柄並蔽閉陛米頁僻壁癖碧別瞥蔑箆偏変片篇編辺返遍便勉娩弁鞭保舗鋪圃捕歩甫補輔穂募墓慕戊暮母簿菩倣俸包呆報奉宝峰峯崩庖抱捧放方朋"],
+["cba1","法泡烹砲縫胞芳萌蓬蜂褒訪豊邦鋒飽鳳鵬乏亡傍剖坊妨帽忘忙房暴望某棒冒紡肪膨謀貌貿鉾防吠頬北僕卜墨撲朴牧睦穆釦勃没殆堀幌奔本翻凡盆摩磨魔麻埋妹昧枚毎哩槙幕膜枕鮪柾鱒桝亦俣又抹末沫迄侭繭麿万慢満"],
+["cca1","漫蔓味未魅巳箕岬密蜜湊蓑稔脈妙粍民眠務夢無牟矛霧鵡椋婿娘冥名命明盟迷銘鳴姪牝滅免棉綿緬面麺摸模茂妄孟毛猛盲網耗蒙儲木黙目杢勿餅尤戻籾貰問悶紋門匁也冶夜爺耶野弥矢厄役約薬訳躍靖柳薮鑓愉愈油癒"],
+["cda1","諭輸唯佑優勇友宥幽悠憂揖有柚湧涌猶猷由祐裕誘遊邑郵雄融夕予余与誉輿預傭幼妖容庸揚揺擁曜楊様洋溶熔用窯羊耀葉蓉要謡踊遥陽養慾抑欲沃浴翌翼淀羅螺裸来莱頼雷洛絡落酪乱卵嵐欄濫藍蘭覧利吏履李梨理璃"],
+["cea1","痢裏裡里離陸律率立葎掠略劉流溜琉留硫粒隆竜龍侶慮旅虜了亮僚両凌寮料梁涼猟療瞭稜糧良諒遼量陵領力緑倫厘林淋燐琳臨輪隣鱗麟瑠塁涙累類令伶例冷励嶺怜玲礼苓鈴隷零霊麗齢暦歴列劣烈裂廉恋憐漣煉簾練聯"],
+["cfa1","蓮連錬呂魯櫓炉賂路露労婁廊弄朗楼榔浪漏牢狼篭老聾蝋郎六麓禄肋録論倭和話歪賄脇惑枠鷲亙亘鰐詫藁蕨椀湾碗腕"],
+["d0a1","弌丐丕个丱丶丼丿乂乖乘亂亅豫亊舒弍于亞亟亠亢亰亳亶从仍仄仆仂仗仞仭仟价伉佚估佛佝佗佇佶侈侏侘佻佩佰侑佯來侖儘俔俟俎俘俛俑俚俐俤俥倚倨倔倪倥倅伜俶倡倩倬俾俯們倆偃假會偕偐偈做偖偬偸傀傚傅傴傲"],
+["d1a1","僉僊傳僂僖僞僥僭僣僮價僵儉儁儂儖儕儔儚儡儺儷儼儻儿兀兒兌兔兢竸兩兪兮冀冂囘册冉冏冑冓冕冖冤冦冢冩冪冫决冱冲冰况冽凅凉凛几處凩凭凰凵凾刄刋刔刎刧刪刮刳刹剏剄剋剌剞剔剪剴剩剳剿剽劍劔劒剱劈劑辨"],
+["d2a1","辧劬劭劼劵勁勍勗勞勣勦飭勠勳勵勸勹匆匈甸匍匐匏匕匚匣匯匱匳匸區卆卅丗卉卍凖卞卩卮夘卻卷厂厖厠厦厥厮厰厶參簒雙叟曼燮叮叨叭叺吁吽呀听吭吼吮吶吩吝呎咏呵咎呟呱呷呰咒呻咀呶咄咐咆哇咢咸咥咬哄哈咨"],
+["d3a1","咫哂咤咾咼哘哥哦唏唔哽哮哭哺哢唹啀啣啌售啜啅啖啗唸唳啝喙喀咯喊喟啻啾喘喞單啼喃喩喇喨嗚嗅嗟嗄嗜嗤嗔嘔嗷嘖嗾嗽嘛嗹噎噐營嘴嘶嘲嘸噫噤嘯噬噪嚆嚀嚊嚠嚔嚏嚥嚮嚶嚴囂嚼囁囃囀囈囎囑囓囗囮囹圀囿圄圉"],
+["d4a1","圈國圍圓團圖嗇圜圦圷圸坎圻址坏坩埀垈坡坿垉垓垠垳垤垪垰埃埆埔埒埓堊埖埣堋堙堝塲堡塢塋塰毀塒堽塹墅墹墟墫墺壞墻墸墮壅壓壑壗壙壘壥壜壤壟壯壺壹壻壼壽夂夊夐夛梦夥夬夭夲夸夾竒奕奐奎奚奘奢奠奧奬奩"],
+["d5a1","奸妁妝佞侫妣妲姆姨姜妍姙姚娥娟娑娜娉娚婀婬婉娵娶婢婪媚媼媾嫋嫂媽嫣嫗嫦嫩嫖嫺嫻嬌嬋嬖嬲嫐嬪嬶嬾孃孅孀孑孕孚孛孥孩孰孳孵學斈孺宀它宦宸寃寇寉寔寐寤實寢寞寥寫寰寶寳尅將專對尓尠尢尨尸尹屁屆屎屓"],
+["d6a1","屐屏孱屬屮乢屶屹岌岑岔妛岫岻岶岼岷峅岾峇峙峩峽峺峭嶌峪崋崕崗嵜崟崛崑崔崢崚崙崘嵌嵒嵎嵋嵬嵳嵶嶇嶄嶂嶢嶝嶬嶮嶽嶐嶷嶼巉巍巓巒巖巛巫已巵帋帚帙帑帛帶帷幄幃幀幎幗幔幟幢幤幇幵并幺麼广庠廁廂廈廐廏"],
+["d7a1","廖廣廝廚廛廢廡廨廩廬廱廳廰廴廸廾弃弉彝彜弋弑弖弩弭弸彁彈彌彎弯彑彖彗彙彡彭彳彷徃徂彿徊很徑徇從徙徘徠徨徭徼忖忻忤忸忱忝悳忿怡恠怙怐怩怎怱怛怕怫怦怏怺恚恁恪恷恟恊恆恍恣恃恤恂恬恫恙悁悍惧悃悚"],
+["d8a1","悄悛悖悗悒悧悋惡悸惠惓悴忰悽惆悵惘慍愕愆惶惷愀惴惺愃愡惻惱愍愎慇愾愨愧慊愿愼愬愴愽慂慄慳慷慘慙慚慫慴慯慥慱慟慝慓慵憙憖憇憬憔憚憊憑憫憮懌懊應懷懈懃懆憺懋罹懍懦懣懶懺懴懿懽懼懾戀戈戉戍戌戔戛"],
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+["8fd2a1","笱笴笽笿筀筁筇筎筕筠筤筦筩筪筭筯筲筳筷箄箉箎箐箑箖箛箞箠箥箬箯箰箲箵箶箺箻箼箽篂篅篈篊篔篖篗篙篚篛篨篪篲篴篵篸篹篺篼篾簁簂簃簄簆簉簋簌簎簏簙簛簠簥簦簨簬簱簳簴簶簹簺籆籊籕籑籒籓籙",5],
+["8fd3a1","籡籣籧籩籭籮籰籲籹籼籽粆粇粏粔粞粠粦粰粶粷粺粻粼粿糄糇糈糉糍糏糓糔糕糗糙糚糝糦糩糫糵紃紇紈紉紏紑紒紓紖紝紞紣紦紪紭紱紼紽紾絀絁絇絈絍絑絓絗絙絚絜絝絥絧絪絰絸絺絻絿綁綂綃綅綆綈綋綌綍綑綖綗綝"],
+["8fd4a1","綞綦綧綪綳綶綷綹緂",4,"緌緍緎緗緙縀緢緥緦緪緫緭緱緵緶緹緺縈縐縑縕縗縜縝縠縧縨縬縭縯縳縶縿繄繅繇繎繐繒繘繟繡繢繥繫繮繯繳繸繾纁纆纇纊纍纑纕纘纚纝纞缼缻缽缾缿罃罄罇罏罒罓罛罜罝罡罣罤罥罦罭"],
+["8fd5a1","罱罽罾罿羀羋羍羏羐羑羖羗羜羡羢羦羪羭羴羼羿翀翃翈翎翏翛翟翣翥翨翬翮翯翲翺翽翾翿耇耈耊耍耎耏耑耓耔耖耝耞耟耠耤耦耬耮耰耴耵耷耹耺耼耾聀聄聠聤聦聭聱聵肁肈肎肜肞肦肧肫肸肹胈胍胏胒胔胕胗胘胠胭胮"],
+["8fd6a1","胰胲胳胶胹胺胾脃脋脖脗脘脜脞脠脤脧脬脰脵脺脼腅腇腊腌腒腗腠腡腧腨腩腭腯腷膁膐膄膅膆膋膎膖膘膛膞膢膮膲膴膻臋臃臅臊臎臏臕臗臛臝臞臡臤臫臬臰臱臲臵臶臸臹臽臿舀舃舏舓舔舙舚舝舡舢舨舲舴舺艃艄艅艆"],
+["8fd7a1","艋艎艏艑艖艜艠艣艧艭艴艻艽艿芀芁芃芄芇芉芊芎芑芔芖芘芚芛芠芡芣芤芧芨芩芪芮芰芲芴芷芺芼芾芿苆苐苕苚苠苢苤苨苪苭苯苶苷苽苾茀茁茇茈茊茋荔茛茝茞茟茡茢茬茭茮茰茳茷茺茼茽荂荃荄荇荍荎荑荕荖荗荰荸"],
+["8fd8a1","荽荿莀莂莄莆莍莒莔莕莘莙莛莜莝莦莧莩莬莾莿菀菇菉菏菐菑菔菝荓菨菪菶菸菹菼萁萆萊萏萑萕萙莭萯萹葅葇葈葊葍葏葑葒葖葘葙葚葜葠葤葥葧葪葰葳葴葶葸葼葽蒁蒅蒒蒓蒕蒞蒦蒨蒩蒪蒯蒱蒴蒺蒽蒾蓀蓂蓇蓈蓌蓏蓓"],
+["8fd9a1","蓜蓧蓪蓯蓰蓱蓲蓷蔲蓺蓻蓽蔂蔃蔇蔌蔎蔐蔜蔞蔢蔣蔤蔥蔧蔪蔫蔯蔳蔴蔶蔿蕆蕏",4,"蕖蕙蕜",6,"蕤蕫蕯蕹蕺蕻蕽蕿薁薅薆薉薋薌薏薓薘薝薟薠薢薥薧薴薶薷薸薼薽薾薿藂藇藊藋藎薭藘藚藟藠藦藨藭藳藶藼"],
+["8fdaa1","藿蘀蘄蘅蘍蘎蘐蘑蘒蘘蘙蘛蘞蘡蘧蘩蘶蘸蘺蘼蘽虀虂虆虒虓虖虗虘虙虝虠",4,"虩虬虯虵虶虷虺蚍蚑蚖蚘蚚蚜蚡蚦蚧蚨蚭蚱蚳蚴蚵蚷蚸蚹蚿蛀蛁蛃蛅蛑蛒蛕蛗蛚蛜蛠蛣蛥蛧蚈蛺蛼蛽蜄蜅蜇蜋蜎蜏蜐蜓蜔蜙蜞蜟蜡蜣"],
+["8fdba1","蜨蜮蜯蜱蜲蜹蜺蜼蜽蜾蝀蝃蝅蝍蝘蝝蝡蝤蝥蝯蝱蝲蝻螃",6,"螋螌螐螓螕螗螘螙螞螠螣螧螬螭螮螱螵螾螿蟁蟈蟉蟊蟎蟕蟖蟙蟚蟜蟟蟢蟣蟤蟪蟫蟭蟱蟳蟸蟺蟿蠁蠃蠆蠉蠊蠋蠐蠙蠒蠓蠔蠘蠚蠛蠜蠞蠟蠨蠭蠮蠰蠲蠵"],
+["8fdca1","蠺蠼衁衃衅衈衉衊衋衎衑衕衖衘衚衜衟衠衤衩衱衹衻袀袘袚袛袜袟袠袨袪袺袽袾裀裊",4,"裑裒裓裛裞裧裯裰裱裵裷褁褆褍褎褏褕褖褘褙褚褜褠褦褧褨褰褱褲褵褹褺褾襀襂襅襆襉襏襒襗襚襛襜襡襢襣襫襮襰襳襵襺"],
+["8fdda1","襻襼襽覉覍覐覔覕覛覜覟覠覥覰覴覵覶覷覼觔",4,"觥觩觫觭觱觳觶觹觽觿訄訅訇訏訑訒訔訕訞訠訢訤訦訫訬訯訵訷訽訾詀詃詅詇詉詍詎詓詖詗詘詜詝詡詥詧詵詶詷詹詺詻詾詿誀誃誆誋誏誐誒誖誗誙誟誧誩誮誯誳"],
+["8fdea1","誶誷誻誾諃諆諈諉諊諑諓諔諕諗諝諟諬諰諴諵諶諼諿謅謆謋謑謜謞謟謊謭謰謷謼譂",4,"譈譒譓譔譙譍譞譣譭譶譸譹譼譾讁讄讅讋讍讏讔讕讜讞讟谸谹谽谾豅豇豉豋豏豑豓豔豗豘豛豝豙豣豤豦豨豩豭豳豵豶豻豾貆"],
+["8fdfa1","貇貋貐貒貓貙貛貜貤貹貺賅賆賉賋賏賖賕賙賝賡賨賬賯賰賲賵賷賸賾賿贁贃贉贒贗贛赥赩赬赮赿趂趄趈趍趐趑趕趞趟趠趦趫趬趯趲趵趷趹趻跀跅跆跇跈跊跎跑跔跕跗跙跤跥跧跬跰趼跱跲跴跽踁踄踅踆踋踑踔踖踠踡踢"],
+["8fe0a1","踣踦踧踱踳踶踷踸踹踽蹀蹁蹋蹍蹎蹏蹔蹛蹜蹝蹞蹡蹢蹩蹬蹭蹯蹰蹱蹹蹺蹻躂躃躉躐躒躕躚躛躝躞躢躧躩躭躮躳躵躺躻軀軁軃軄軇軏軑軔軜軨軮軰軱軷軹軺軭輀輂輇輈輏輐輖輗輘輞輠輡輣輥輧輨輬輭輮輴輵輶輷輺轀轁"],
+["8fe1a1","轃轇轏轑",4,"轘轝轞轥辝辠辡辤辥辦辵辶辸达迀迁迆迊迋迍运迒迓迕迠迣迤迨迮迱迵迶迻迾适逄逈逌逘逛逨逩逯逪逬逭逳逴逷逿遃遄遌遛遝遢遦遧遬遰遴遹邅邈邋邌邎邐邕邗邘邙邛邠邡邢邥邰邲邳邴邶邽郌邾郃"],
+["8fe2a1","郄郅郇郈郕郗郘郙郜郝郟郥郒郶郫郯郰郴郾郿鄀鄄鄅鄆鄈鄍鄐鄔鄖鄗鄘鄚鄜鄞鄠鄥鄢鄣鄧鄩鄮鄯鄱鄴鄶鄷鄹鄺鄼鄽酃酇酈酏酓酗酙酚酛酡酤酧酭酴酹酺酻醁醃醅醆醊醎醑醓醔醕醘醞醡醦醨醬醭醮醰醱醲醳醶醻醼醽醿"],
+["8fe3a1","釂釃釅釓釔釗釙釚釞釤釥釩釪釬",5,"釷釹釻釽鈀鈁鈄鈅鈆鈇鈉鈊鈌鈐鈒鈓鈖鈘鈜鈝鈣鈤鈥鈦鈨鈮鈯鈰鈳鈵鈶鈸鈹鈺鈼鈾鉀鉂鉃鉆鉇鉊鉍鉎鉏鉑鉘鉙鉜鉝鉠鉡鉥鉧鉨鉩鉮鉯鉰鉵",4,"鉻鉼鉽鉿銈銉銊銍銎銒銗"],
+["8fe4a1","銙銟銠銤銥銧銨銫銯銲銶銸銺銻銼銽銿",4,"鋅鋆鋇鋈鋋鋌鋍鋎鋐鋓鋕鋗鋘鋙鋜鋝鋟鋠鋡鋣鋥鋧鋨鋬鋮鋰鋹鋻鋿錀錂錈錍錑錔錕錜錝錞錟錡錤錥錧錩錪錳錴錶錷鍇鍈鍉鍐鍑鍒鍕鍗鍘鍚鍞鍤鍥鍧鍩鍪鍭鍯鍰鍱鍳鍴鍶"],
+["8fe5a1","鍺鍽鍿鎀鎁鎂鎈鎊鎋鎍鎏鎒鎕鎘鎛鎞鎡鎣鎤鎦鎨鎫鎴鎵鎶鎺鎩鏁鏄鏅鏆鏇鏉",4,"鏓鏙鏜鏞鏟鏢鏦鏧鏹鏷鏸鏺鏻鏽鐁鐂鐄鐈鐉鐍鐎鐏鐕鐖鐗鐟鐮鐯鐱鐲鐳鐴鐻鐿鐽鑃鑅鑈鑊鑌鑕鑙鑜鑟鑡鑣鑨鑫鑭鑮鑯鑱鑲钄钃镸镹"],
+["8fe6a1","镾閄閈閌閍閎閝閞閟閡閦閩閫閬閴閶閺閽閿闆闈闉闋闐闑闒闓闙闚闝闞闟闠闤闦阝阞阢阤阥阦阬阱阳阷阸阹阺阼阽陁陒陔陖陗陘陡陮陴陻陼陾陿隁隂隃隄隉隑隖隚隝隟隤隥隦隩隮隯隳隺雊雒嶲雘雚雝雞雟雩雯雱雺霂"],
+["8fe7a1","霃霅霉霚霛霝霡霢霣霨霱霳靁靃靊靎靏靕靗靘靚靛靣靧靪靮靳靶靷靸靻靽靿鞀鞉鞕鞖鞗鞙鞚鞞鞟鞢鞬鞮鞱鞲鞵鞶鞸鞹鞺鞼鞾鞿韁韄韅韇韉韊韌韍韎韐韑韔韗韘韙韝韞韠韛韡韤韯韱韴韷韸韺頇頊頙頍頎頔頖頜頞頠頣頦"],
+["8fe8a1","頫頮頯頰頲頳頵頥頾顄顇顊顑顒顓顖顗顙顚顢顣顥顦顪顬颫颭颮颰颴颷颸颺颻颿飂飅飈飌飡飣飥飦飧飪飳飶餂餇餈餑餕餖餗餚餛餜餟餢餦餧餫餱",4,"餹餺餻餼饀饁饆饇饈饍饎饔饘饙饛饜饞饟饠馛馝馟馦馰馱馲馵"],
+["8fe9a1","馹馺馽馿駃駉駓駔駙駚駜駞駧駪駫駬駰駴駵駹駽駾騂騃騄騋騌騐騑騖騞騠騢騣騤騧騭騮騳騵騶騸驇驁驄驊驋驌驎驑驔驖驝骪骬骮骯骲骴骵骶骹骻骾骿髁髃髆髈髎髐髒髕髖髗髛髜髠髤髥髧髩髬髲髳髵髹髺髽髿",4],
+["8feaa1","鬄鬅鬈鬉鬋鬌鬍鬎鬐鬒鬖鬙鬛鬜鬠鬦鬫鬭鬳鬴鬵鬷鬹鬺鬽魈魋魌魕魖魗魛魞魡魣魥魦魨魪",4,"魳魵魷魸魹魿鮀鮄鮅鮆鮇鮉鮊鮋鮍鮏鮐鮔鮚鮝鮞鮦鮧鮩鮬鮰鮱鮲鮷鮸鮻鮼鮾鮿鯁鯇鯈鯎鯐鯗鯘鯝鯟鯥鯧鯪鯫鯯鯳鯷鯸"],
+["8feba1","鯹鯺鯽鯿鰀鰂鰋鰏鰑鰖鰘鰙鰚鰜鰞鰢鰣鰦",4,"鰱鰵鰶鰷鰽鱁鱃鱄鱅鱉鱊鱎鱏鱐鱓鱔鱖鱘鱛鱝鱞鱟鱣鱩鱪鱜鱫鱨鱮鱰鱲鱵鱷鱻鳦鳲鳷鳹鴋鴂鴑鴗鴘鴜鴝鴞鴯鴰鴲鴳鴴鴺鴼鵅鴽鵂鵃鵇鵊鵓鵔鵟鵣鵢鵥鵩鵪鵫鵰鵶鵷鵻"],
+["8feca1","鵼鵾鶃鶄鶆鶊鶍鶎鶒鶓鶕鶖鶗鶘鶡鶪鶬鶮鶱鶵鶹鶼鶿鷃鷇鷉鷊鷔鷕鷖鷗鷚鷞鷟鷠鷥鷧鷩鷫鷮鷰鷳鷴鷾鸊鸂鸇鸎鸐鸑鸒鸕鸖鸙鸜鸝鹺鹻鹼麀麂麃麄麅麇麎麏麖麘麛麞麤麨麬麮麯麰麳麴麵黆黈黋黕黟黤黧黬黭黮黰黱黲黵"],
+["8feda1","黸黿鼂鼃鼉鼏鼐鼑鼒鼔鼖鼗鼙鼚鼛鼟鼢鼦鼪鼫鼯鼱鼲鼴鼷鼹鼺鼼鼽鼿齁齃",4,"齓齕齖齗齘齚齝齞齨齩齭",4,"齳齵齺齽龏龐龑龒龔龖龗龞龡龢龣龥"]
+]
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/gb18030-ranges.json b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/gb18030-ranges.json
new file mode 100644
index 0000000..85c6934
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/gb18030-ranges.json
@@ -0,0 +1 @@
+{"uChars":[128,165,169,178,184,216,226,235,238,244,248,251,253,258,276,284,300,325,329,334,364,463,465,467,469,471,473,475,477,506,594,610,712,716,730,930,938,962,970,1026,1104,1106,8209,8215,8218,8222,8231,8241,8244,8246,8252,8365,8452,8454,8458,8471,8482,8556,8570,8596,8602,8713,8720,8722,8726,8731,8737,8740,8742,8748,8751,8760,8766,8777,8781,8787,8802,8808,8816,8854,8858,8870,8896,8979,9322,9372,9548,9588,9616,9622,9634,9652,9662,9672,9676,9680,9702,9735,9738,9793,9795,11906,11909,11913,11917,11928,11944,11947,11951,11956,11960,11964,11979,12284,12292,12312,12319,12330,12351,12436,12447,12535,12543,12586,12842,12850,12964,13200,13215,13218,13253,13263,13267,13270,13384,13428,13727,13839,13851,14617,14703,14801,14816,14964,15183,15471,15585,16471,16736,17208,17325,17330,17374,17623,17997,18018,18212,18218,18301,18318,18760,18811,18814,18820,18823,18844,18848,18872,19576,19620,19738,19887,40870,59244,59336,59367,59413,59417,59423,59431,59437,59443,59452,59460,59478,59493,63789,63866,63894,63976,63986,64016,64018,64021,64025,64034,64037,64042,65074,65093,65107,65112,65127,65132,65375,65510,65536],"gbChars":[0,36,38,45,50,81,89,95,96,100,103,104,105,109,126,133,148,172,175,179,208,306,307,308,309,310,311,312,313,341,428,443,544,545,558,741,742,749,750,805,819,820,7922,7924,7925,7927,7934,7943,7944,7945,7950,8062,8148,8149,8152,8164,8174,8236,8240,8262,8264,8374,8380,8381,8384,8388,8390,8392,8393,8394,8396,8401,8406,8416,8419,8424,8437,8439,8445,8482,8485,8496,8521,8603,8936,8946,9046,9050,9063,9066,9076,9092,9100,9108,9111,9113,9131,9162,9164,9218,9219,11329,11331,11334,11336,11346,11361,11363,11366,11370,11372,11375,11389,11682,11686,11687,11692,11694,11714,11716,11723,11725,11730,11736,11982,11989,12102,12336,12348,12350,12384,12393,12395,12397,12510,12553,12851,12962,12973,13738,13823,13919,13933,14080,14298,14585,14698,15583,15847,16318,16434,16438,16481,16729,17102,17122,17315,17320,17402,17418,17859,17909,17911,17915,17916,17936,17939,17961,18664,18703,18814,18962,19043,33469,33470,33471,33484,33485,33490,33497,33501,33505,33513,33520,33536,33550,37845,37921,37948,38029,38038,38064,38065,38066,38069,38075,38076,38078,39108,39109,39113,39114,39115,39116,39265,39394,189000]}
\ No newline at end of file
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/gbk-added.json b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/gbk-added.json
new file mode 100644
index 0000000..b742e36
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/gbk-added.json
@@ -0,0 +1,56 @@
+[
+["a140","",62],
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diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/shiftjis.json b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/shiftjis.json
new file mode 100644
index 0000000..5a3a43c
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/tables/shiftjis.json
@@ -0,0 +1,125 @@
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+["e780","轢轣轤辜辟辣辭辯辷迚迥迢迪迯邇迴逅迹迺逑逕逡逍逞逖逋逧逶逵逹迸遏遐遑遒逎遉逾遖遘遞遨遯遶隨遲邂遽邁邀邊邉邏邨邯邱邵郢郤扈郛鄂鄒鄙鄲鄰酊酖酘酣酥酩酳酲醋醉醂醢醫醯醪醵醴醺釀釁釉釋釐釖釟釡釛釼釵釶鈞釿鈔鈬鈕鈑鉞鉗鉅鉉鉤鉈銕鈿鉋鉐銜銖銓銛鉚鋏銹銷鋩錏鋺鍄錮"],
+["e840","錙錢錚錣錺錵錻鍜鍠鍼鍮鍖鎰鎬鎭鎔鎹鏖鏗鏨鏥鏘鏃鏝鏐鏈鏤鐚鐔鐓鐃鐇鐐鐶鐫鐵鐡鐺鑁鑒鑄鑛鑠鑢鑞鑪鈩鑰鑵鑷鑽鑚鑼鑾钁鑿閂閇閊閔閖閘閙"],
+["e880","閠閨閧閭閼閻閹閾闊濶闃闍闌闕闔闖關闡闥闢阡阨阮阯陂陌陏陋陷陜陞陝陟陦陲陬隍隘隕隗險隧隱隲隰隴隶隸隹雎雋雉雍襍雜霍雕雹霄霆霈霓霎霑霏霖霙霤霪霰霹霽霾靄靆靈靂靉靜靠靤靦靨勒靫靱靹鞅靼鞁靺鞆鞋鞏鞐鞜鞨鞦鞣鞳鞴韃韆韈韋韜韭齏韲竟韶韵頏頌頸頤頡頷頽顆顏顋顫顯顰"],
+["e940","顱顴顳颪颯颱颶飄飃飆飩飫餃餉餒餔餘餡餝餞餤餠餬餮餽餾饂饉饅饐饋饑饒饌饕馗馘馥馭馮馼駟駛駝駘駑駭駮駱駲駻駸騁騏騅駢騙騫騷驅驂驀驃"],
+["e980","騾驕驍驛驗驟驢驥驤驩驫驪骭骰骼髀髏髑髓體髞髟髢髣髦髯髫髮髴髱髷髻鬆鬘鬚鬟鬢鬣鬥鬧鬨鬩鬪鬮鬯鬲魄魃魏魍魎魑魘魴鮓鮃鮑鮖鮗鮟鮠鮨鮴鯀鯊鮹鯆鯏鯑鯒鯣鯢鯤鯔鯡鰺鯲鯱鯰鰕鰔鰉鰓鰌鰆鰈鰒鰊鰄鰮鰛鰥鰤鰡鰰鱇鰲鱆鰾鱚鱠鱧鱶鱸鳧鳬鳰鴉鴈鳫鴃鴆鴪鴦鶯鴣鴟鵄鴕鴒鵁鴿鴾鵆鵈"],
+["ea40","鵝鵞鵤鵑鵐鵙鵲鶉鶇鶫鵯鵺鶚鶤鶩鶲鷄鷁鶻鶸鶺鷆鷏鷂鷙鷓鷸鷦鷭鷯鷽鸚鸛鸞鹵鹹鹽麁麈麋麌麒麕麑麝麥麩麸麪麭靡黌黎黏黐黔黜點黝黠黥黨黯"],
+["ea80","黴黶黷黹黻黼黽鼇鼈皷鼕鼡鼬鼾齊齒齔齣齟齠齡齦齧齬齪齷齲齶龕龜龠堯槇遙瑤凜熙"],
+["ed40","纊褜鍈銈蓜俉炻昱棈鋹曻彅丨仡仼伀伃伹佖侒侊侚侔俍偀倢俿倞偆偰偂傔僴僘兊兤冝冾凬刕劜劦勀勛匀匇匤卲厓厲叝﨎咜咊咩哿喆坙坥垬埈埇﨏"],
+["ed80","塚增墲夋奓奛奝奣妤妺孖寀甯寘寬尞岦岺峵崧嵓﨑嵂嵭嶸嶹巐弡弴彧德忞恝悅悊惞惕愠惲愑愷愰憘戓抦揵摠撝擎敎昀昕昻昉昮昞昤晥晗晙晴晳暙暠暲暿曺朎朗杦枻桒柀栁桄棏﨓楨﨔榘槢樰橫橆橳橾櫢櫤毖氿汜沆汯泚洄涇浯涖涬淏淸淲淼渹湜渧渼溿澈澵濵瀅瀇瀨炅炫焏焄煜煆煇凞燁燾犱"],
+["ee40","犾猤猪獷玽珉珖珣珒琇珵琦琪琩琮瑢璉璟甁畯皂皜皞皛皦益睆劯砡硎硤硺礰礼神祥禔福禛竑竧靖竫箞精絈絜綷綠緖繒罇羡羽茁荢荿菇菶葈蒴蕓蕙"],
+["ee80","蕫﨟薰蘒﨡蠇裵訒訷詹誧誾諟諸諶譓譿賰賴贒赶﨣軏﨤逸遧郞都鄕鄧釚釗釞釭釮釤釥鈆鈐鈊鈺鉀鈼鉎鉙鉑鈹鉧銧鉷鉸鋧鋗鋙鋐﨧鋕鋠鋓錥錡鋻﨨錞鋿錝錂鍰鍗鎤鏆鏞鏸鐱鑅鑈閒隆﨩隝隯霳霻靃靍靏靑靕顗顥飯飼餧館馞驎髙髜魵魲鮏鮱鮻鰀鵰鵫鶴鸙黑"],
+["eeef","ⅰ",9,"￢￤＇＂"],
+["f040","",62],
+["f080","",124],
+["f140","",62],
+["f180","",124],
+["f240","",62],
+["f280","",124],
+["f340","",62],
+["f380","",124],
+["f440","",62],
+["f480","",124],
+["f540","",62],
+["f580","",124],
+["f640","",62],
+["f680","",124],
+["f740","",62],
+["f780","",124],
+["f840","",62],
+["f880","",124],
+["f940",""],
+["fa40","ⅰ",9,"Ⅰ",9,"￢￤＇＂㈱№℡∵纊褜鍈銈蓜俉炻昱棈鋹曻彅丨仡仼伀伃伹佖侒侊侚侔俍偀倢俿倞偆偰偂傔僴僘兊"],
+["fa80","兤冝冾凬刕劜劦勀勛匀匇匤卲厓厲叝﨎咜咊咩哿喆坙坥垬埈埇﨏塚增墲夋奓奛奝奣妤妺孖寀甯寘寬尞岦岺峵崧嵓﨑嵂嵭嶸嶹巐弡弴彧德忞恝悅悊惞惕愠惲愑愷愰憘戓抦揵摠撝擎敎昀昕昻昉昮昞昤晥晗晙晴晳暙暠暲暿曺朎朗杦枻桒柀栁桄棏﨓楨﨔榘槢樰橫橆橳橾櫢櫤毖氿汜沆汯泚洄涇浯"],
+["fb40","涖涬淏淸淲淼渹湜渧渼溿澈澵濵瀅瀇瀨炅炫焏焄煜煆煇凞燁燾犱犾猤猪獷玽珉珖珣珒琇珵琦琪琩琮瑢璉璟甁畯皂皜皞皛皦益睆劯砡硎硤硺礰礼神"],
+["fb80","祥禔福禛竑竧靖竫箞精絈絜綷綠緖繒罇羡羽茁荢荿菇菶葈蒴蕓蕙蕫﨟薰蘒﨡蠇裵訒訷詹誧誾諟諸諶譓譿賰賴贒赶﨣軏﨤逸遧郞都鄕鄧釚釗釞釭釮釤釥鈆鈐鈊鈺鉀鈼鉎鉙鉑鈹鉧銧鉷鉸鋧鋗鋙鋐﨧鋕鋠鋓錥錡鋻﨨錞鋿錝錂鍰鍗鎤鏆鏞鏸鐱鑅鑈閒隆﨩隝隯霳霻靃靍靏靑靕顗顥飯飼餧館馞驎髙"],
+["fc40","髜魵魲鮏鮱鮻鰀鵰鵫鶴鸙黑"]
+]
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/utf16.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/utf16.js
new file mode 100644
index 0000000..97d0669
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/utf16.js
@@ -0,0 +1,197 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// Note: UTF16-LE (or UCS2) codec is Node.js native. See encodings/internal.js
+
+// == UTF16-BE codec. ==========================================================
+
+exports.utf16be = Utf16BECodec;
+function Utf16BECodec() {
+}
+
+Utf16BECodec.prototype.encoder = Utf16BEEncoder;
+Utf16BECodec.prototype.decoder = Utf16BEDecoder;
+Utf16BECodec.prototype.bomAware = true;
+
+
+// -- Encoding
+
+function Utf16BEEncoder() {
+}
+
+Utf16BEEncoder.prototype.write = function(str) {
+    var buf = Buffer.from(str, 'ucs2');
+    for (var i = 0; i < buf.length; i += 2) {
+        var tmp = buf[i]; buf[i] = buf[i+1]; buf[i+1] = tmp;
+    }
+    return buf;
+}
+
+Utf16BEEncoder.prototype.end = function() {
+}
+
+
+// -- Decoding
+
+function Utf16BEDecoder() {
+    this.overflowByte = -1;
+}
+
+Utf16BEDecoder.prototype.write = function(buf) {
+    if (buf.length == 0)
+        return '';
+
+    var buf2 = Buffer.alloc(buf.length + 1),
+        i = 0, j = 0;
+
+    if (this.overflowByte !== -1) {
+        buf2[0] = buf[0];
+        buf2[1] = this.overflowByte;
+        i = 1; j = 2;
+    }
+
+    for (; i < buf.length-1; i += 2, j+= 2) {
+        buf2[j] = buf[i+1];
+        buf2[j+1] = buf[i];
+    }
+
+    this.overflowByte = (i == buf.length-1) ? buf[buf.length-1] : -1;
+
+    return buf2.slice(0, j).toString('ucs2');
+}
+
+Utf16BEDecoder.prototype.end = function() {
+    this.overflowByte = -1;
+}
+
+
+// == UTF-16 codec =============================================================
+// Decoder chooses automatically from UTF-16LE and UTF-16BE using BOM and space-based heuristic.
+// Defaults to UTF-16LE, as it's prevalent and default in Node.
+// http://en.wikipedia.org/wiki/UTF-16 and http://encoding.spec.whatwg.org/#utf-16le
+// Decoder default can be changed: iconv.decode(buf, 'utf16', {defaultEncoding: 'utf-16be'});
+
+// Encoder uses UTF-16LE and prepends BOM (which can be overridden with addBOM: false).
+
+exports.utf16 = Utf16Codec;
+function Utf16Codec(codecOptions, iconv) {
+    this.iconv = iconv;
+}
+
+Utf16Codec.prototype.encoder = Utf16Encoder;
+Utf16Codec.prototype.decoder = Utf16Decoder;
+
+
+// -- Encoding (pass-through)
+
+function Utf16Encoder(options, codec) {
+    options = options || {};
+    if (options.addBOM === undefined)
+        options.addBOM = true;
+    this.encoder = codec.iconv.getEncoder('utf-16le', options);
+}
+
+Utf16Encoder.prototype.write = function(str) {
+    return this.encoder.write(str);
+}
+
+Utf16Encoder.prototype.end = function() {
+    return this.encoder.end();
+}
+
+
+// -- Decoding
+
+function Utf16Decoder(options, codec) {
+    this.decoder = null;
+    this.initialBufs = [];
+    this.initialBufsLen = 0;
+
+    this.options = options || {};
+    this.iconv = codec.iconv;
+}
+
+Utf16Decoder.prototype.write = function(buf) {
+    if (!this.decoder) {
+        // Codec is not chosen yet. Accumulate initial bytes.
+        this.initialBufs.push(buf);
+        this.initialBufsLen += buf.length;
+        
+        if (this.initialBufsLen < 16) // We need more bytes to use space heuristic (see below)
+            return '';
+
+        // We have enough bytes -> detect endianness.
+        var encoding = detectEncoding(this.initialBufs, this.options.defaultEncoding);
+        this.decoder = this.iconv.getDecoder(encoding, this.options);
+
+        var resStr = '';
+        for (var i = 0; i < this.initialBufs.length; i++)
+            resStr += this.decoder.write(this.initialBufs[i]);
+
+        this.initialBufs.length = this.initialBufsLen = 0;
+        return resStr;
+    }
+
+    return this.decoder.write(buf);
+}
+
+Utf16Decoder.prototype.end = function() {
+    if (!this.decoder) {
+        var encoding = detectEncoding(this.initialBufs, this.options.defaultEncoding);
+        this.decoder = this.iconv.getDecoder(encoding, this.options);
+
+        var resStr = '';
+        for (var i = 0; i < this.initialBufs.length; i++)
+            resStr += this.decoder.write(this.initialBufs[i]);
+
+        var trail = this.decoder.end();
+        if (trail)
+            resStr += trail;
+
+        this.initialBufs.length = this.initialBufsLen = 0;
+        return resStr;
+    }
+    return this.decoder.end();
+}
+
+function detectEncoding(bufs, defaultEncoding) {
+    var b = [];
+    var charsProcessed = 0;
+    var asciiCharsLE = 0, asciiCharsBE = 0; // Number of ASCII chars when decoded as LE or BE.
+
+    outer_loop:
+    for (var i = 0; i < bufs.length; i++) {
+        var buf = bufs[i];
+        for (var j = 0; j < buf.length; j++) {
+            b.push(buf[j]);
+            if (b.length === 2) {
+                if (charsProcessed === 0) {
+                    // Check BOM first.
+                    if (b[0] === 0xFF && b[1] === 0xFE) return 'utf-16le';
+                    if (b[0] === 0xFE && b[1] === 0xFF) return 'utf-16be';
+                }
+
+                if (b[0] === 0 && b[1] !== 0) asciiCharsBE++;
+                if (b[0] !== 0 && b[1] === 0) asciiCharsLE++;
+
+                b.length = 0;
+                charsProcessed++;
+
+                if (charsProcessed >= 100) {
+                    break outer_loop;
+                }
+            }
+        }
+    }
+
+    // Make decisions.
+    // Most of the time, the content has ASCII chars (U+00**), but the opposite (U+**00) is uncommon.
+    // So, we count ASCII as if it was LE or BE, and decide from that.
+    if (asciiCharsBE > asciiCharsLE) return 'utf-16be';
+    if (asciiCharsBE < asciiCharsLE) return 'utf-16le';
+
+    // Couldn't decide (likely all zeros or not enough data).
+    return defaultEncoding || 'utf-16le';
+}
+
+
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/utf32.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/utf32.js
new file mode 100644
index 0000000..2fa900a
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/utf32.js
@@ -0,0 +1,319 @@
+'use strict';
+
+var Buffer = require('safer-buffer').Buffer;
+
+// == UTF32-LE/BE codec. ==========================================================
+
+exports._utf32 = Utf32Codec;
+
+function Utf32Codec(codecOptions, iconv) {
+    this.iconv = iconv;
+    this.bomAware = true;
+    this.isLE = codecOptions.isLE;
+}
+
+exports.utf32le = { type: '_utf32', isLE: true };
+exports.utf32be = { type: '_utf32', isLE: false };
+
+// Aliases
+exports.ucs4le = 'utf32le';
+exports.ucs4be = 'utf32be';
+
+Utf32Codec.prototype.encoder = Utf32Encoder;
+Utf32Codec.prototype.decoder = Utf32Decoder;
+
+// -- Encoding
+
+function Utf32Encoder(options, codec) {
+    this.isLE = codec.isLE;
+    this.highSurrogate = 0;
+}
+
+Utf32Encoder.prototype.write = function(str) {
+    var src = Buffer.from(str, 'ucs2');
+    var dst = Buffer.alloc(src.length * 2);
+    var write32 = this.isLE ? dst.writeUInt32LE : dst.writeUInt32BE;
+    var offset = 0;
+
+    for (var i = 0; i < src.length; i += 2) {
+        var code = src.readUInt16LE(i);
+        var isHighSurrogate = (0xD800 <= code && code < 0xDC00);
+        var isLowSurrogate = (0xDC00 <= code && code < 0xE000);
+
+        if (this.highSurrogate) {
+            if (isHighSurrogate || !isLowSurrogate) {
+                // There shouldn't be two high surrogates in a row, nor a high surrogate which isn't followed by a low
+                // surrogate. If this happens, keep the pending high surrogate as a stand-alone semi-invalid character
+                // (technically wrong, but expected by some applications, like Windows file names).
+                write32.call(dst, this.highSurrogate, offset);
+                offset += 4;
+            }
+            else {
+                // Create 32-bit value from high and low surrogates;
+                var codepoint = (((this.highSurrogate - 0xD800) << 10) | (code - 0xDC00)) + 0x10000;
+
+                write32.call(dst, codepoint, offset);
+                offset += 4;
+                this.highSurrogate = 0;
+
+                continue;
+            }
+        }
+
+        if (isHighSurrogate)
+            this.highSurrogate = code;
+        else {
+            // Even if the current character is a low surrogate, with no previous high surrogate, we'll
+            // encode it as a semi-invalid stand-alone character for the same reasons expressed above for
+            // unpaired high surrogates.
+            write32.call(dst, code, offset);
+            offset += 4;
+            this.highSurrogate = 0;
+        }
+    }
+
+    if (offset < dst.length)
+        dst = dst.slice(0, offset);
+
+    return dst;
+};
+
+Utf32Encoder.prototype.end = function() {
+    // Treat any leftover high surrogate as a semi-valid independent character.
+    if (!this.highSurrogate)
+        return;
+
+    var buf = Buffer.alloc(4);
+
+    if (this.isLE)
+        buf.writeUInt32LE(this.highSurrogate, 0);
+    else
+        buf.writeUInt32BE(this.highSurrogate, 0);
+
+    this.highSurrogate = 0;
+
+    return buf;
+};
+
+// -- Decoding
+
+function Utf32Decoder(options, codec) {
+    this.isLE = codec.isLE;
+    this.badChar = codec.iconv.defaultCharUnicode.charCodeAt(0);
+    this.overflow = [];
+}
+
+Utf32Decoder.prototype.write = function(src) {
+    if (src.length === 0)
+        return '';
+
+    var i = 0;
+    var codepoint = 0;
+    var dst = Buffer.alloc(src.length + 4);
+    var offset = 0;
+    var isLE = this.isLE;
+    var overflow = this.overflow;
+    var badChar = this.badChar;
+
+    if (overflow.length > 0) {
+        for (; i < src.length && overflow.length < 4; i++)
+            overflow.push(src[i]);
+        
+        if (overflow.length === 4) {
+            // NOTE: codepoint is a signed int32 and can be negative.
+            // NOTE: We copied this block from below to help V8 optimize it (it works with array, not buffer).
+            if (isLE) {
+                codepoint = overflow[i] | (overflow[i+1] << 8) | (overflow[i+2] << 16) | (overflow[i+3] << 24);
+            } else {
+                codepoint = overflow[i+3] | (overflow[i+2] << 8) | (overflow[i+1] << 16) | (overflow[i] << 24);
+            }
+            overflow.length = 0;
+
+            offset = _writeCodepoint(dst, offset, codepoint, badChar);
+        }
+    }
+
+    // Main loop. Should be as optimized as possible.
+    for (; i < src.length - 3; i += 4) {
+        // NOTE: codepoint is a signed int32 and can be negative.
+        if (isLE) {
+            codepoint = src[i] | (src[i+1] << 8) | (src[i+2] << 16) | (src[i+3] << 24);
+        } else {
+            codepoint = src[i+3] | (src[i+2] << 8) | (src[i+1] << 16) | (src[i] << 24);
+        }
+        offset = _writeCodepoint(dst, offset, codepoint, badChar);
+    }
+
+    // Keep overflowing bytes.
+    for (; i < src.length; i++) {
+        overflow.push(src[i]);
+    }
+
+    return dst.slice(0, offset).toString('ucs2');
+};
+
+function _writeCodepoint(dst, offset, codepoint, badChar) {
+    // NOTE: codepoint is signed int32 and can be negative. We keep it that way to help V8 with optimizations.
+    if (codepoint < 0 || codepoint > 0x10FFFF) {
+        // Not a valid Unicode codepoint
+        codepoint = badChar;
+    } 
+
+    // Ephemeral Planes: Write high surrogate.
+    if (codepoint >= 0x10000) {
+        codepoint -= 0x10000;
+
+        var high = 0xD800 | (codepoint >> 10);
+        dst[offset++] = high & 0xff;
+        dst[offset++] = high >> 8;
+
+        // Low surrogate is written below.
+        var codepoint = 0xDC00 | (codepoint & 0x3FF);
+    }
+
+    // Write BMP char or low surrogate.
+    dst[offset++] = codepoint & 0xff;
+    dst[offset++] = codepoint >> 8;
+
+    return offset;
+};
+
+Utf32Decoder.prototype.end = function() {
+    this.overflow.length = 0;
+};
+
+// == UTF-32 Auto codec =============================================================
+// Decoder chooses automatically from UTF-32LE and UTF-32BE using BOM and space-based heuristic.
+// Defaults to UTF-32LE. http://en.wikipedia.org/wiki/UTF-32
+// Encoder/decoder default can be changed: iconv.decode(buf, 'utf32', {defaultEncoding: 'utf-32be'});
+
+// Encoder prepends BOM (which can be overridden with (addBOM: false}).
+
+exports.utf32 = Utf32AutoCodec;
+exports.ucs4 = 'utf32';
+
+function Utf32AutoCodec(options, iconv) {
+    this.iconv = iconv;
+}
+
+Utf32AutoCodec.prototype.encoder = Utf32AutoEncoder;
+Utf32AutoCodec.prototype.decoder = Utf32AutoDecoder;
+
+// -- Encoding
+
+function Utf32AutoEncoder(options, codec) {
+    options = options || {};
+
+    if (options.addBOM === undefined)
+        options.addBOM = true;
+
+    this.encoder = codec.iconv.getEncoder(options.defaultEncoding || 'utf-32le', options);
+}
+
+Utf32AutoEncoder.prototype.write = function(str) {
+    return this.encoder.write(str);
+};
+
+Utf32AutoEncoder.prototype.end = function() {
+    return this.encoder.end();
+};
+
+// -- Decoding
+
+function Utf32AutoDecoder(options, codec) {
+    this.decoder = null;
+    this.initialBufs = [];
+    this.initialBufsLen = 0;
+    this.options = options || {};
+    this.iconv = codec.iconv;
+}
+
+Utf32AutoDecoder.prototype.write = function(buf) {
+    if (!this.decoder) { 
+        // Codec is not chosen yet. Accumulate initial bytes.
+        this.initialBufs.push(buf);
+        this.initialBufsLen += buf.length;
+
+        if (this.initialBufsLen < 32) // We need more bytes to use space heuristic (see below)
+            return '';
+
+        // We have enough bytes -> detect endianness.
+        var encoding = detectEncoding(this.initialBufs, this.options.defaultEncoding);
+        this.decoder = this.iconv.getDecoder(encoding, this.options);
+
+        var resStr = '';
+        for (var i = 0; i < this.initialBufs.length; i++)
+            resStr += this.decoder.write(this.initialBufs[i]);
+
+        this.initialBufs.length = this.initialBufsLen = 0;
+        return resStr;
+    }
+
+    return this.decoder.write(buf);
+};
+
+Utf32AutoDecoder.prototype.end = function() {
+    if (!this.decoder) {
+        var encoding = detectEncoding(this.initialBufs, this.options.defaultEncoding);
+        this.decoder = this.iconv.getDecoder(encoding, this.options);
+
+        var resStr = '';
+        for (var i = 0; i < this.initialBufs.length; i++)
+            resStr += this.decoder.write(this.initialBufs[i]);
+
+        var trail = this.decoder.end();
+        if (trail)
+            resStr += trail;
+
+        this.initialBufs.length = this.initialBufsLen = 0;
+        return resStr;
+    }
+
+    return this.decoder.end();
+};
+
+function detectEncoding(bufs, defaultEncoding) {
+    var b = [];
+    var charsProcessed = 0;
+    var invalidLE = 0, invalidBE = 0;   // Number of invalid chars when decoded as LE or BE.
+    var bmpCharsLE = 0, bmpCharsBE = 0; // Number of BMP chars when decoded as LE or BE.
+
+    outer_loop:
+    for (var i = 0; i < bufs.length; i++) {
+        var buf = bufs[i];
+        for (var j = 0; j < buf.length; j++) {
+            b.push(buf[j]);
+            if (b.length === 4) {
+                if (charsProcessed === 0) {
+                    // Check BOM first.
+                    if (b[0] === 0xFF && b[1] === 0xFE && b[2] === 0 && b[3] === 0) {
+                        return 'utf-32le';
+                    }
+                    if (b[0] === 0 && b[1] === 0 && b[2] === 0xFE && b[3] === 0xFF) {
+                        return 'utf-32be';
+                    }
+                }
+
+                if (b[0] !== 0 || b[1] > 0x10) invalidBE++;
+                if (b[3] !== 0 || b[2] > 0x10) invalidLE++;
+
+                if (b[0] === 0 && b[1] === 0 && (b[2] !== 0 || b[3] !== 0)) bmpCharsBE++;
+                if ((b[0] !== 0 || b[1] !== 0) && b[2] === 0 && b[3] === 0) bmpCharsLE++;
+
+                b.length = 0;
+                charsProcessed++;
+
+                if (charsProcessed >= 100) {
+                    break outer_loop;
+                }
+            }
+        }
+    }
+
+    // Make decisions.
+    if (bmpCharsBE - invalidBE > bmpCharsLE - invalidLE)  return 'utf-32be';
+    if (bmpCharsBE - invalidBE < bmpCharsLE - invalidLE)  return 'utf-32le';
+
+    // Couldn't decide (likely all zeros or not enough data).
+    return defaultEncoding || 'utf-32le';
+}
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/encodings/utf7.js b/server/node_modules/encoding/node_modules/iconv-lite/encodings/utf7.js
new file mode 100644
index 0000000..eacae34
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/encodings/utf7.js
@@ -0,0 +1,290 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// UTF-7 codec, according to https://tools.ietf.org/html/rfc2152
+// See also below a UTF-7-IMAP codec, according to http://tools.ietf.org/html/rfc3501#section-5.1.3
+
+exports.utf7 = Utf7Codec;
+exports.unicode11utf7 = 'utf7'; // Alias UNICODE-1-1-UTF-7
+function Utf7Codec(codecOptions, iconv) {
+    this.iconv = iconv;
+};
+
+Utf7Codec.prototype.encoder = Utf7Encoder;
+Utf7Codec.prototype.decoder = Utf7Decoder;
+Utf7Codec.prototype.bomAware = true;
+
+
+// -- Encoding
+
+var nonDirectChars = /[^A-Za-z0-9',-\.\/:\? \n\r\t]+/g;
+
+function Utf7Encoder(options, codec) {
+    this.iconv = codec.iconv;
+}
+
+Utf7Encoder.prototype.write = function(str) {
+    // Naive implementation.
+    // Non-direct chars are encoded as "+<base64>-"; single "+" char is encoded as "+-".
+    return Buffer.from(str.replace(nonDirectChars, function(chunk) {
+        return "+" + (chunk === '+' ? '' : 
+            this.iconv.encode(chunk, 'utf16-be').toString('base64').replace(/=+$/, '')) 
+            + "-";
+    }.bind(this)));
+}
+
+Utf7Encoder.prototype.end = function() {
+}
+
+
+// -- Decoding
+
+function Utf7Decoder(options, codec) {
+    this.iconv = codec.iconv;
+    this.inBase64 = false;
+    this.base64Accum = '';
+}
+
+var base64Regex = /[A-Za-z0-9\/+]/;
+var base64Chars = [];
+for (var i = 0; i < 256; i++)
+    base64Chars[i] = base64Regex.test(String.fromCharCode(i));
+
+var plusChar = '+'.charCodeAt(0), 
+    minusChar = '-'.charCodeAt(0),
+    andChar = '&'.charCodeAt(0);
+
+Utf7Decoder.prototype.write = function(buf) {
+    var res = "", lastI = 0,
+        inBase64 = this.inBase64,
+        base64Accum = this.base64Accum;
+
+    // The decoder is more involved as we must handle chunks in stream.
+
+    for (var i = 0; i < buf.length; i++) {
+        if (!inBase64) { // We're in direct mode.
+            // Write direct chars until '+'
+            if (buf[i] == plusChar) {
+                res += this.iconv.decode(buf.slice(lastI, i), "ascii"); // Write direct chars.
+                lastI = i+1;
+                inBase64 = true;
+            }
+        } else { // We decode base64.
+            if (!base64Chars[buf[i]]) { // Base64 ended.
+                if (i == lastI && buf[i] == minusChar) {// "+-" -> "+"
+                    res += "+";
+                } else {
+                    var b64str = base64Accum + this.iconv.decode(buf.slice(lastI, i), "ascii");
+                    res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
+                }
+
+                if (buf[i] != minusChar) // Minus is absorbed after base64.
+                    i--;
+
+                lastI = i+1;
+                inBase64 = false;
+                base64Accum = '';
+            }
+        }
+    }
+
+    if (!inBase64) {
+        res += this.iconv.decode(buf.slice(lastI), "ascii"); // Write direct chars.
+    } else {
+        var b64str = base64Accum + this.iconv.decode(buf.slice(lastI), "ascii");
+
+        var canBeDecoded = b64str.length - (b64str.length % 8); // Minimal chunk: 2 quads -> 2x3 bytes -> 3 chars.
+        base64Accum = b64str.slice(canBeDecoded); // The rest will be decoded in future.
+        b64str = b64str.slice(0, canBeDecoded);
+
+        res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
+    }
+
+    this.inBase64 = inBase64;
+    this.base64Accum = base64Accum;
+
+    return res;
+}
+
+Utf7Decoder.prototype.end = function() {
+    var res = "";
+    if (this.inBase64 && this.base64Accum.length > 0)
+        res = this.iconv.decode(Buffer.from(this.base64Accum, 'base64'), "utf16-be");
+
+    this.inBase64 = false;
+    this.base64Accum = '';
+    return res;
+}
+
+
+// UTF-7-IMAP codec.
+// RFC3501 Sec. 5.1.3 Modified UTF-7 (http://tools.ietf.org/html/rfc3501#section-5.1.3)
+// Differences:
+//  * Base64 part is started by "&" instead of "+"
+//  * Direct characters are 0x20-0x7E, except "&" (0x26)
+//  * In Base64, "," is used instead of "/"
+//  * Base64 must not be used to represent direct characters.
+//  * No implicit shift back from Base64 (should always end with '-')
+//  * String must end in non-shifted position.
+//  * "-&" while in base64 is not allowed.
+
+
+exports.utf7imap = Utf7IMAPCodec;
+function Utf7IMAPCodec(codecOptions, iconv) {
+    this.iconv = iconv;
+};
+
+Utf7IMAPCodec.prototype.encoder = Utf7IMAPEncoder;
+Utf7IMAPCodec.prototype.decoder = Utf7IMAPDecoder;
+Utf7IMAPCodec.prototype.bomAware = true;
+
+
+// -- Encoding
+
+function Utf7IMAPEncoder(options, codec) {
+    this.iconv = codec.iconv;
+    this.inBase64 = false;
+    this.base64Accum = Buffer.alloc(6);
+    this.base64AccumIdx = 0;
+}
+
+Utf7IMAPEncoder.prototype.write = function(str) {
+    var inBase64 = this.inBase64,
+        base64Accum = this.base64Accum,
+        base64AccumIdx = this.base64AccumIdx,
+        buf = Buffer.alloc(str.length*5 + 10), bufIdx = 0;
+
+    for (var i = 0; i < str.length; i++) {
+        var uChar = str.charCodeAt(i);
+        if (0x20 <= uChar && uChar <= 0x7E) { // Direct character or '&'.
+            if (inBase64) {
+                if (base64AccumIdx > 0) {
+                    bufIdx += buf.write(base64Accum.slice(0, base64AccumIdx).toString('base64').replace(/\//g, ',').replace(/=+$/, ''), bufIdx);
+                    base64AccumIdx = 0;
+                }
+
+                buf[bufIdx++] = minusChar; // Write '-', then go to direct mode.
+                inBase64 = false;
+            }
+
+            if (!inBase64) {
+                buf[bufIdx++] = uChar; // Write direct character
+
+                if (uChar === andChar)  // Ampersand -> '&-'
+                    buf[bufIdx++] = minusChar;
+            }
+
+        } else { // Non-direct character
+            if (!inBase64) {
+                buf[bufIdx++] = andChar; // Write '&', then go to base64 mode.
+                inBase64 = true;
+            }
+            if (inBase64) {
+                base64Accum[base64AccumIdx++] = uChar >> 8;
+                base64Accum[base64AccumIdx++] = uChar & 0xFF;
+
+                if (base64AccumIdx == base64Accum.length) {
+                    bufIdx += buf.write(base64Accum.toString('base64').replace(/\//g, ','), bufIdx);
+                    base64AccumIdx = 0;
+                }
+            }
+        }
+    }
+
+    this.inBase64 = inBase64;
+    this.base64AccumIdx = base64AccumIdx;
+
+    return buf.slice(0, bufIdx);
+}
+
+Utf7IMAPEncoder.prototype.end = function() {
+    var buf = Buffer.alloc(10), bufIdx = 0;
+    if (this.inBase64) {
+        if (this.base64AccumIdx > 0) {
+            bufIdx += buf.write(this.base64Accum.slice(0, this.base64AccumIdx).toString('base64').replace(/\//g, ',').replace(/=+$/, ''), bufIdx);
+            this.base64AccumIdx = 0;
+        }
+
+        buf[bufIdx++] = minusChar; // Write '-', then go to direct mode.
+        this.inBase64 = false;
+    }
+
+    return buf.slice(0, bufIdx);
+}
+
+
+// -- Decoding
+
+function Utf7IMAPDecoder(options, codec) {
+    this.iconv = codec.iconv;
+    this.inBase64 = false;
+    this.base64Accum = '';
+}
+
+var base64IMAPChars = base64Chars.slice();
+base64IMAPChars[','.charCodeAt(0)] = true;
+
+Utf7IMAPDecoder.prototype.write = function(buf) {
+    var res = "", lastI = 0,
+        inBase64 = this.inBase64,
+        base64Accum = this.base64Accum;
+
+    // The decoder is more involved as we must handle chunks in stream.
+    // It is forgiving, closer to standard UTF-7 (for example, '-' is optional at the end).
+
+    for (var i = 0; i < buf.length; i++) {
+        if (!inBase64) { // We're in direct mode.
+            // Write direct chars until '&'
+            if (buf[i] == andChar) {
+                res += this.iconv.decode(buf.slice(lastI, i), "ascii"); // Write direct chars.
+                lastI = i+1;
+                inBase64 = true;
+            }
+        } else { // We decode base64.
+            if (!base64IMAPChars[buf[i]]) { // Base64 ended.
+                if (i == lastI && buf[i] == minusChar) { // "&-" -> "&"
+                    res += "&";
+                } else {
+                    var b64str = base64Accum + this.iconv.decode(buf.slice(lastI, i), "ascii").replace(/,/g, '/');
+                    res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
+                }
+
+                if (buf[i] != minusChar) // Minus may be absorbed after base64.
+                    i--;
+
+                lastI = i+1;
+                inBase64 = false;
+                base64Accum = '';
+            }
+        }
+    }
+
+    if (!inBase64) {
+        res += this.iconv.decode(buf.slice(lastI), "ascii"); // Write direct chars.
+    } else {
+        var b64str = base64Accum + this.iconv.decode(buf.slice(lastI), "ascii").replace(/,/g, '/');
+
+        var canBeDecoded = b64str.length - (b64str.length % 8); // Minimal chunk: 2 quads -> 2x3 bytes -> 3 chars.
+        base64Accum = b64str.slice(canBeDecoded); // The rest will be decoded in future.
+        b64str = b64str.slice(0, canBeDecoded);
+
+        res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
+    }
+
+    this.inBase64 = inBase64;
+    this.base64Accum = base64Accum;
+
+    return res;
+}
+
+Utf7IMAPDecoder.prototype.end = function() {
+    var res = "";
+    if (this.inBase64 && this.base64Accum.length > 0)
+        res = this.iconv.decode(Buffer.from(this.base64Accum, 'base64'), "utf16-be");
+
+    this.inBase64 = false;
+    this.base64Accum = '';
+    return res;
+}
+
+
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/lib/bom-handling.js b/server/node_modules/encoding/node_modules/iconv-lite/lib/bom-handling.js
new file mode 100644
index 0000000..1050872
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/lib/bom-handling.js
@@ -0,0 +1,52 @@
+"use strict";
+
+var BOMChar = '\uFEFF';
+
+exports.PrependBOM = PrependBOMWrapper
+function PrependBOMWrapper(encoder, options) {
+    this.encoder = encoder;
+    this.addBOM = true;
+}
+
+PrependBOMWrapper.prototype.write = function(str) {
+    if (this.addBOM) {
+        str = BOMChar + str;
+        this.addBOM = false;
+    }
+
+    return this.encoder.write(str);
+}
+
+PrependBOMWrapper.prototype.end = function() {
+    return this.encoder.end();
+}
+
+
+//------------------------------------------------------------------------------
+
+exports.StripBOM = StripBOMWrapper;
+function StripBOMWrapper(decoder, options) {
+    this.decoder = decoder;
+    this.pass = false;
+    this.options = options || {};
+}
+
+StripBOMWrapper.prototype.write = function(buf) {
+    var res = this.decoder.write(buf);
+    if (this.pass || !res)
+        return res;
+
+    if (res[0] === BOMChar) {
+        res = res.slice(1);
+        if (typeof this.options.stripBOM === 'function')
+            this.options.stripBOM();
+    }
+
+    this.pass = true;
+    return res;
+}
+
+StripBOMWrapper.prototype.end = function() {
+    return this.decoder.end();
+}
+
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/lib/index.d.ts b/server/node_modules/encoding/node_modules/iconv-lite/lib/index.d.ts
new file mode 100644
index 0000000..99f200f
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/lib/index.d.ts
@@ -0,0 +1,41 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License.
+ *  REQUIREMENT: This definition is dependent on the @types/node definition.
+ *  Install with `npm install @types/node --save-dev`
+ *--------------------------------------------------------------------------------------------*/
+
+declare module 'iconv-lite' {
+	// Basic API
+	export function decode(buffer: Buffer, encoding: string, options?: Options): string;
+
+	export function encode(content: string, encoding: string, options?: Options): Buffer;
+
+	export function encodingExists(encoding: string): boolean;
+
+	// Stream API
+	export function decodeStream(encoding: string, options?: Options): NodeJS.ReadWriteStream;
+
+	export function encodeStream(encoding: string, options?: Options): NodeJS.ReadWriteStream;
+
+	// Low-level stream APIs
+	export function getEncoder(encoding: string, options?: Options): EncoderStream;
+
+	export function getDecoder(encoding: string, options?: Options): DecoderStream;
+}
+
+export interface Options {
+    stripBOM?: boolean;
+    addBOM?: boolean;
+    defaultEncoding?: string;
+}
+
+export interface EncoderStream {
+	write(str: string): Buffer;
+	end(): Buffer | undefined;
+}
+
+export interface DecoderStream {
+	write(buf: Buffer): string;
+	end(): string | undefined;
+}
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/lib/index.js b/server/node_modules/encoding/node_modules/iconv-lite/lib/index.js
new file mode 100644
index 0000000..657701c
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/lib/index.js
@@ -0,0 +1,180 @@
+"use strict";
+
+var Buffer = require("safer-buffer").Buffer;
+
+var bomHandling = require("./bom-handling"),
+    iconv = module.exports;
+
+// All codecs and aliases are kept here, keyed by encoding name/alias.
+// They are lazy loaded in `iconv.getCodec` from `encodings/index.js`.
+iconv.encodings = null;
+
+// Characters emitted in case of error.
+iconv.defaultCharUnicode = '�';
+iconv.defaultCharSingleByte = '?';
+
+// Public API.
+iconv.encode = function encode(str, encoding, options) {
+    str = "" + (str || ""); // Ensure string.
+
+    var encoder = iconv.getEncoder(encoding, options);
+
+    var res = encoder.write(str);
+    var trail = encoder.end();
+    
+    return (trail && trail.length > 0) ? Buffer.concat([res, trail]) : res;
+}
+
+iconv.decode = function decode(buf, encoding, options) {
+    if (typeof buf === 'string') {
+        if (!iconv.skipDecodeWarning) {
+            console.error('Iconv-lite warning: decode()-ing strings is deprecated. Refer to https://github.com/ashtuchkin/iconv-lite/wiki/Use-Buffers-when-decoding');
+            iconv.skipDecodeWarning = true;
+        }
+
+        buf = Buffer.from("" + (buf || ""), "binary"); // Ensure buffer.
+    }
+
+    var decoder = iconv.getDecoder(encoding, options);
+
+    var res = decoder.write(buf);
+    var trail = decoder.end();
+
+    return trail ? (res + trail) : res;
+}
+
+iconv.encodingExists = function encodingExists(enc) {
+    try {
+        iconv.getCodec(enc);
+        return true;
+    } catch (e) {
+        return false;
+    }
+}
+
+// Legacy aliases to convert functions
+iconv.toEncoding = iconv.encode;
+iconv.fromEncoding = iconv.decode;
+
+// Search for a codec in iconv.encodings. Cache codec data in iconv._codecDataCache.
+iconv._codecDataCache = {};
+iconv.getCodec = function getCodec(encoding) {
+    if (!iconv.encodings)
+        iconv.encodings = require("../encodings"); // Lazy load all encoding definitions.
+    
+    // Canonicalize encoding name: strip all non-alphanumeric chars and appended year.
+    var enc = iconv._canonicalizeEncoding(encoding);
+
+    // Traverse iconv.encodings to find actual codec.
+    var codecOptions = {};
+    while (true) {
+        var codec = iconv._codecDataCache[enc];
+        if (codec)
+            return codec;
+
+        var codecDef = iconv.encodings[enc];
+
+        switch (typeof codecDef) {
+            case "string": // Direct alias to other encoding.
+                enc = codecDef;
+                break;
+
+            case "object": // Alias with options. Can be layered.
+                for (var key in codecDef)
+                    codecOptions[key] = codecDef[key];
+
+                if (!codecOptions.encodingName)
+                    codecOptions.encodingName = enc;
+                
+                enc = codecDef.type;
+                break;
+
+            case "function": // Codec itself.
+                if (!codecOptions.encodingName)
+                    codecOptions.encodingName = enc;
+
+                // The codec function must load all tables and return object with .encoder and .decoder methods.
+                // It'll be called only once (for each different options object).
+                codec = new codecDef(codecOptions, iconv);
+
+                iconv._codecDataCache[codecOptions.encodingName] = codec; // Save it to be reused later.
+                return codec;
+
+            default:
+                throw new Error("Encoding not recognized: '" + encoding + "' (searched as: '"+enc+"')");
+        }
+    }
+}
+
+iconv._canonicalizeEncoding = function(encoding) {
+    // Canonicalize encoding name: strip all non-alphanumeric chars and appended year.
+    return (''+encoding).toLowerCase().replace(/:\d{4}$|[^0-9a-z]/g, "");
+}
+
+iconv.getEncoder = function getEncoder(encoding, options) {
+    var codec = iconv.getCodec(encoding),
+        encoder = new codec.encoder(options, codec);
+
+    if (codec.bomAware && options && options.addBOM)
+        encoder = new bomHandling.PrependBOM(encoder, options);
+
+    return encoder;
+}
+
+iconv.getDecoder = function getDecoder(encoding, options) {
+    var codec = iconv.getCodec(encoding),
+        decoder = new codec.decoder(options, codec);
+
+    if (codec.bomAware && !(options && options.stripBOM === false))
+        decoder = new bomHandling.StripBOM(decoder, options);
+
+    return decoder;
+}
+
+// Streaming API
+// NOTE: Streaming API naturally depends on 'stream' module from Node.js. Unfortunately in browser environments this module can add
+// up to 100Kb to the output bundle. To avoid unnecessary code bloat, we don't enable Streaming API in browser by default.
+// If you would like to enable it explicitly, please add the following code to your app:
+// > iconv.enableStreamingAPI(require('stream'));
+iconv.enableStreamingAPI = function enableStreamingAPI(stream_module) {
+    if (iconv.supportsStreams)
+        return;
+
+    // Dependency-inject stream module to create IconvLite stream classes.
+    var streams = require("./streams")(stream_module);
+
+    // Not public API yet, but expose the stream classes.
+    iconv.IconvLiteEncoderStream = streams.IconvLiteEncoderStream;
+    iconv.IconvLiteDecoderStream = streams.IconvLiteDecoderStream;
+
+    // Streaming API.
+    iconv.encodeStream = function encodeStream(encoding, options) {
+        return new iconv.IconvLiteEncoderStream(iconv.getEncoder(encoding, options), options);
+    }
+
+    iconv.decodeStream = function decodeStream(encoding, options) {
+        return new iconv.IconvLiteDecoderStream(iconv.getDecoder(encoding, options), options);
+    }
+
+    iconv.supportsStreams = true;
+}
+
+// Enable Streaming API automatically if 'stream' module is available and non-empty (the majority of environments).
+var stream_module;
+try {
+    stream_module = require("stream");
+} catch (e) {}
+
+if (stream_module && stream_module.Transform) {
+    iconv.enableStreamingAPI(stream_module);
+
+} else {
+    // In rare cases where 'stream' module is not available by default, throw a helpful exception.
+    iconv.encodeStream = iconv.decodeStream = function() {
+        throw new Error("iconv-lite Streaming API is not enabled. Use iconv.enableStreamingAPI(require('stream')); to enable it.");
+    };
+}
+
+if ("Ā" != "\u0100") {
+    console.error("iconv-lite warning: js files use non-utf8 encoding. See https://github.com/ashtuchkin/iconv-lite/wiki/Javascript-source-file-encodings for more info.");
+}
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/lib/streams.js b/server/node_modules/encoding/node_modules/iconv-lite/lib/streams.js
new file mode 100644
index 0000000..a150648
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/lib/streams.js
@@ -0,0 +1,109 @@
+"use strict";
+
+var Buffer = require("safer-buffer").Buffer;
+
+// NOTE: Due to 'stream' module being pretty large (~100Kb, significant in browser environments), 
+// we opt to dependency-inject it instead of creating a hard dependency.
+module.exports = function(stream_module) {
+    var Transform = stream_module.Transform;
+
+    // == Encoder stream =======================================================
+
+    function IconvLiteEncoderStream(conv, options) {
+        this.conv = conv;
+        options = options || {};
+        options.decodeStrings = false; // We accept only strings, so we don't need to decode them.
+        Transform.call(this, options);
+    }
+
+    IconvLiteEncoderStream.prototype = Object.create(Transform.prototype, {
+        constructor: { value: IconvLiteEncoderStream }
+    });
+
+    IconvLiteEncoderStream.prototype._transform = function(chunk, encoding, done) {
+        if (typeof chunk != 'string')
+            return done(new Error("Iconv encoding stream needs strings as its input."));
+        try {
+            var res = this.conv.write(chunk);
+            if (res && res.length) this.push(res);
+            done();
+        }
+        catch (e) {
+            done(e);
+        }
+    }
+
+    IconvLiteEncoderStream.prototype._flush = function(done) {
+        try {
+            var res = this.conv.end();
+            if (res && res.length) this.push(res);
+            done();
+        }
+        catch (e) {
+            done(e);
+        }
+    }
+
+    IconvLiteEncoderStream.prototype.collect = function(cb) {
+        var chunks = [];
+        this.on('error', cb);
+        this.on('data', function(chunk) { chunks.push(chunk); });
+        this.on('end', function() {
+            cb(null, Buffer.concat(chunks));
+        });
+        return this;
+    }
+
+
+    // == Decoder stream =======================================================
+
+    function IconvLiteDecoderStream(conv, options) {
+        this.conv = conv;
+        options = options || {};
+        options.encoding = this.encoding = 'utf8'; // We output strings.
+        Transform.call(this, options);
+    }
+
+    IconvLiteDecoderStream.prototype = Object.create(Transform.prototype, {
+        constructor: { value: IconvLiteDecoderStream }
+    });
+
+    IconvLiteDecoderStream.prototype._transform = function(chunk, encoding, done) {
+        if (!Buffer.isBuffer(chunk) && !(chunk instanceof Uint8Array))
+            return done(new Error("Iconv decoding stream needs buffers as its input."));
+        try {
+            var res = this.conv.write(chunk);
+            if (res && res.length) this.push(res, this.encoding);
+            done();
+        }
+        catch (e) {
+            done(e);
+        }
+    }
+
+    IconvLiteDecoderStream.prototype._flush = function(done) {
+        try {
+            var res = this.conv.end();
+            if (res && res.length) this.push(res, this.encoding);                
+            done();
+        }
+        catch (e) {
+            done(e);
+        }
+    }
+
+    IconvLiteDecoderStream.prototype.collect = function(cb) {
+        var res = '';
+        this.on('error', cb);
+        this.on('data', function(chunk) { res += chunk; });
+        this.on('end', function() {
+            cb(null, res);
+        });
+        return this;
+    }
+
+    return {
+        IconvLiteEncoderStream: IconvLiteEncoderStream,
+        IconvLiteDecoderStream: IconvLiteDecoderStream,
+    };
+};
diff --git a/server/node_modules/encoding/node_modules/iconv-lite/package.json b/server/node_modules/encoding/node_modules/iconv-lite/package.json
new file mode 100644
index 0000000..d351115
--- /dev/null
+++ b/server/node_modules/encoding/node_modules/iconv-lite/package.json
@@ -0,0 +1,44 @@
+{
+    "name": "iconv-lite",
+    "description": "Convert character encodings in pure javascript.",
+    "version": "0.6.3",
+    "license": "MIT",
+    "keywords": [
+        "iconv",
+        "convert",
+        "charset",
+        "icu"
+    ],
+    "author": "Alexander Shtuchkin <ashtuchkin@gmail.com>",
+    "main": "./lib/index.js",
+    "typings": "./lib/index.d.ts",
+    "homepage": "https://github.com/ashtuchkin/iconv-lite",
+    "bugs": "https://github.com/ashtuchkin/iconv-lite/issues",
+    "repository": {
+        "type": "git",
+        "url": "git://github.com/ashtuchkin/iconv-lite.git"
+    },
+    "engines": {
+        "node": ">=0.10.0"
+    },
+    "scripts": {
+        "coverage": "c8 _mocha --grep .",
+        "test": "mocha --reporter spec --grep ."
+    },
+    "browser": {
+        "stream": false
+    },
+    "devDependencies": {
+        "async": "^3.2.0",
+        "c8": "^7.2.0",
+        "errto": "^0.2.1",
+        "iconv": "^2.3.5",
+        "mocha": "^3.5.3",
+        "request": "^2.88.2",
+        "semver": "^6.3.0",
+        "unorm": "^1.6.0"
+    },
+    "dependencies": {
+        "safer-buffer": ">= 2.1.2 < 3.0.0"
+    }
+}
diff --git a/server/node_modules/encoding/package.json b/server/node_modules/encoding/package.json
new file mode 100644
index 0000000..773a943
--- /dev/null
+++ b/server/node_modules/encoding/package.json
@@ -0,0 +1,18 @@
+{
+    "name": "encoding",
+    "version": "0.1.13",
+    "description": "Convert encodings, uses iconv-lite",
+    "main": "lib/encoding.js",
+    "scripts": {
+        "test": "nodeunit test"
+    },
+    "repository": "https://github.com/andris9/encoding.git",
+    "author": "Andris Reinman",
+    "license": "MIT",
+    "dependencies": {
+        "iconv-lite": "^0.6.2"
+    },
+    "devDependencies": {
+        "nodeunit": "0.11.3"
+    }
+}
diff --git a/server/node_modules/encoding/test/test.js b/server/node_modules/encoding/test/test.js
new file mode 100644
index 0000000..3a7dfee
--- /dev/null
+++ b/server/node_modules/encoding/test/test.js
@@ -0,0 +1,49 @@
+'use strict';
+
+var encoding = require('../lib/encoding');
+
+exports['General tests'] = {
+    'From UTF-8 to Latin_1': function (test) {
+        var input = 'ÕÄÖÜ',
+            expected = Buffer.from([0xd5, 0xc4, 0xd6, 0xdc]);
+        test.deepEqual(encoding.convert(input, 'latin1'), expected);
+        test.done();
+    },
+
+    'From Latin_1 to UTF-8': function (test) {
+        var input = Buffer.from([0xd5, 0xc4, 0xd6, 0xdc]),
+            expected = 'ÕÄÖÜ';
+        test.deepEqual(encoding.convert(input, 'utf-8', 'latin1').toString(), expected);
+        test.done();
+    },
+
+    'From UTF-8 to UTF-8': function (test) {
+        var input = 'ÕÄÖÜ',
+            expected = Buffer.from('ÕÄÖÜ');
+        test.deepEqual(encoding.convert(input, 'utf-8', 'utf-8'), expected);
+        test.done();
+    },
+
+    'From Latin_13 to Latin_15': function (test) {
+        var input = Buffer.from([0xd5, 0xc4, 0xd6, 0xdc, 0xd0]),
+            expected = Buffer.from([0xd5, 0xc4, 0xd6, 0xdc, 0xa6]);
+        test.deepEqual(encoding.convert(input, 'latin_15', 'latin13'), expected);
+        test.done();
+    }
+
+    /*
+    // ISO-2022-JP is not supported by iconv-lite
+    "From ISO-2022-JP to UTF-8 with Iconv": function (test) {
+        var input = Buffer.from(
+            "GyRCM1g5OzU7PVEwdzgmPSQ4IUYkMnFKczlwGyhC",
+            "base64"
+        ),
+        expected = Buffer.from(
+            "5a2m5qCh5oqA6KGT5ZOh56CU5L+u5qSc6KiO5Lya5aCx5ZGK",
+            "base64"
+        );
+        test.deepEqual(encoding.convert(input, "utf-8", "ISO-2022-JP"), expected);
+        test.done();
+    },
+    */
+};
diff --git a/server/node_modules/end-of-stream/LICENSE b/server/node_modules/end-of-stream/LICENSE
new file mode 100644
index 0000000..757562e
--- /dev/null
+++ b/server/node_modules/end-of-stream/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Mathias Buus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/end-of-stream/README.md b/server/node_modules/end-of-stream/README.md
new file mode 100644
index 0000000..857b14b
--- /dev/null
+++ b/server/node_modules/end-of-stream/README.md
@@ -0,0 +1,54 @@
+# end-of-stream
+
+A node module that calls a callback when a readable/writable/duplex stream has completed or failed.
+
+	npm install end-of-stream
+
+[![Build status](https://travis-ci.org/mafintosh/end-of-stream.svg?branch=master)](https://travis-ci.org/mafintosh/end-of-stream)
+
+## Usage
+
+Simply pass a stream and a callback to the `eos`.
+Both legacy streams, streams2 and stream3 are supported.
+
+``` js
+var eos = require('end-of-stream');
+
+eos(readableStream, function(err) {
+  // this will be set to the stream instance
+	if (err) return console.log('stream had an error or closed early');
+	console.log('stream has ended', this === readableStream);
+});
+
+eos(writableStream, function(err) {
+	if (err) return console.log('stream had an error or closed early');
+	console.log('stream has finished', this === writableStream);
+});
+
+eos(duplexStream, function(err) {
+	if (err) return console.log('stream had an error or closed early');
+	console.log('stream has ended and finished', this === duplexStream);
+});
+
+eos(duplexStream, {readable:false}, function(err) {
+	if (err) return console.log('stream had an error or closed early');
+	console.log('stream has finished but might still be readable');
+});
+
+eos(duplexStream, {writable:false}, function(err) {
+	if (err) return console.log('stream had an error or closed early');
+	console.log('stream has ended but might still be writable');
+});
+
+eos(readableStream, {error:false}, function(err) {
+	// do not treat emit('error', err) as a end-of-stream
+});
+```
+
+## License
+
+MIT
+
+## Related
+
+`end-of-stream` is part of the [mississippi stream utility collection](https://github.com/maxogden/mississippi) which includes more useful stream modules similar to this one.
diff --git a/server/node_modules/end-of-stream/index.js b/server/node_modules/end-of-stream/index.js
new file mode 100644
index 0000000..7ce47e9
--- /dev/null
+++ b/server/node_modules/end-of-stream/index.js
@@ -0,0 +1,96 @@
+var once = require('once');
+
+var noop = function() {};
+
+var qnt = global.Bare ? queueMicrotask : process.nextTick.bind(process);
+
+var isRequest = function(stream) {
+	return stream.setHeader && typeof stream.abort === 'function';
+};
+
+var isChildProcess = function(stream) {
+	return stream.stdio && Array.isArray(stream.stdio) && stream.stdio.length === 3
+};
+
+var eos = function(stream, opts, callback) {
+	if (typeof opts === 'function') return eos(stream, null, opts);
+	if (!opts) opts = {};
+
+	callback = once(callback || noop);
+
+	var ws = stream._writableState;
+	var rs = stream._readableState;
+	var readable = opts.readable || (opts.readable !== false && stream.readable);
+	var writable = opts.writable || (opts.writable !== false && stream.writable);
+	var cancelled = false;
+
+	var onlegacyfinish = function() {
+		if (!stream.writable) onfinish();
+	};
+
+	var onfinish = function() {
+		writable = false;
+		if (!readable) callback.call(stream);
+	};
+
+	var onend = function() {
+		readable = false;
+		if (!writable) callback.call(stream);
+	};
+
+	var onexit = function(exitCode) {
+		callback.call(stream, exitCode ? new Error('exited with error code: ' + exitCode) : null);
+	};
+
+	var onerror = function(err) {
+		callback.call(stream, err);
+	};
+
+	var onclose = function() {
+		qnt(onclosenexttick);
+	};
+
+	var onclosenexttick = function() {
+		if (cancelled) return;
+		if (readable && !(rs && (rs.ended && !rs.destroyed))) return callback.call(stream, new Error('premature close'));
+		if (writable && !(ws && (ws.ended && !ws.destroyed))) return callback.call(stream, new Error('premature close'));
+	};
+
+	var onrequest = function() {
+		stream.req.on('finish', onfinish);
+	};
+
+	if (isRequest(stream)) {
+		stream.on('complete', onfinish);
+		stream.on('abort', onclose);
+		if (stream.req) onrequest();
+		else stream.on('request', onrequest);
+	} else if (writable && !ws) { // legacy streams
+		stream.on('end', onlegacyfinish);
+		stream.on('close', onlegacyfinish);
+	}
+
+	if (isChildProcess(stream)) stream.on('exit', onexit);
+
+	stream.on('end', onend);
+	stream.on('finish', onfinish);
+	if (opts.error !== false) stream.on('error', onerror);
+	stream.on('close', onclose);
+
+	return function() {
+		cancelled = true;
+		stream.removeListener('complete', onfinish);
+		stream.removeListener('abort', onclose);
+		stream.removeListener('request', onrequest);
+		if (stream.req) stream.req.removeListener('finish', onfinish);
+		stream.removeListener('end', onlegacyfinish);
+		stream.removeListener('close', onlegacyfinish);
+		stream.removeListener('finish', onfinish);
+		stream.removeListener('exit', onexit);
+		stream.removeListener('end', onend);
+		stream.removeListener('error', onerror);
+		stream.removeListener('close', onclose);
+	};
+};
+
+module.exports = eos;
diff --git a/server/node_modules/end-of-stream/package.json b/server/node_modules/end-of-stream/package.json
new file mode 100644
index 0000000..0b530cd
--- /dev/null
+++ b/server/node_modules/end-of-stream/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "end-of-stream",
+  "version": "1.4.5",
+  "description": "Call a callback when a readable/writable/duplex stream has completed or failed.",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/mafintosh/end-of-stream.git"
+  },
+  "dependencies": {
+    "once": "^1.4.0"
+  },
+  "scripts": {
+    "test": "node test.js"
+  },
+  "files": [
+    "index.js"
+  ],
+  "keywords": [
+    "stream",
+    "streams",
+    "callback",
+    "finish",
+    "close",
+    "end",
+    "wait"
+  ],
+  "bugs": {
+    "url": "https://github.com/mafintosh/end-of-stream/issues"
+  },
+  "homepage": "https://github.com/mafintosh/end-of-stream",
+  "main": "index.js",
+  "author": "Mathias Buus <mathiasbuus@gmail.com>",
+  "license": "MIT",
+  "devDependencies": {
+    "tape": "^4.11.0"
+  }
+}
diff --git a/server/node_modules/env-paths/index.d.ts b/server/node_modules/env-paths/index.d.ts
new file mode 100644
index 0000000..277ddc0
--- /dev/null
+++ b/server/node_modules/env-paths/index.d.ts
@@ -0,0 +1,101 @@
+declare namespace envPaths {
+	export interface Options {
+		/**
+		__Don't use this option unless you really have to!__
+
+		Suffix appended to the project name to avoid name conflicts with native apps. Pass an empty string to disable it.
+
+		@default 'nodejs'
+		*/
+		readonly suffix?: string;
+	}
+
+	export interface Paths {
+		/**
+		Directory for data files.
+
+		Example locations (with the default `nodejs` suffix):
+
+		- macOS: `~/Library/Application Support/MyApp-nodejs`
+		- Windows: `%LOCALAPPDATA%\MyApp-nodejs\Data` (for example, `C:\Users\USERNAME\AppData\Local\MyApp-nodejs\Data`)
+		- Linux: `~/.local/share/MyApp-nodejs` (or `$XDG_DATA_HOME/MyApp-nodejs`)
+		*/
+		readonly data: string;
+
+		/**
+		Directory for data files.
+
+		Example locations (with the default `nodejs` suffix):
+
+		- macOS: `~/Library/Preferences/MyApp-nodejs`
+		- Windows: `%APPDATA%\MyApp-nodejs\Config` (for example, `C:\Users\USERNAME\AppData\Roaming\MyApp-nodejs\Config`)
+		- Linux: `~/.config/MyApp-nodejs` (or `$XDG_CONFIG_HOME/MyApp-nodejs`)
+		*/
+		readonly config: string;
+
+		/**
+		Directory for non-essential data files.
+
+		Example locations (with the default `nodejs` suffix):
+
+		- macOS: `~/Library/Caches/MyApp-nodejs`
+		- Windows: `%LOCALAPPDATA%\MyApp-nodejs\Cache` (for example, `C:\Users\USERNAME\AppData\Local\MyApp-nodejs\Cache`)
+		- Linux: `~/.cache/MyApp-nodejs` (or `$XDG_CACHE_HOME/MyApp-nodejs`)
+		*/
+		readonly cache: string;
+
+		/**
+		Directory for log files.
+
+		Example locations (with the default `nodejs` suffix):
+
+		- macOS: `~/Library/Logs/MyApp-nodejs`
+		- Windows: `%LOCALAPPDATA%\MyApp-nodejs\Log` (for example, `C:\Users\USERNAME\AppData\Local\MyApp-nodejs\Log`)
+		- Linux: `~/.local/state/MyApp-nodejs` (or `$XDG_STATE_HOME/MyApp-nodejs`)
+		*/
+		readonly log: string;
+
+		/**
+		Directory for temporary files.
+
+		Example locations (with the default `nodejs` suffix):
+
+		- macOS: `/var/folders/jf/f2twvvvs5jl_m49tf034ffpw0000gn/T/MyApp-nodejs`
+		- Windows: `%LOCALAPPDATA%\Temp\MyApp-nodejs` (for example, `C:\Users\USERNAME\AppData\Local\Temp\MyApp-nodejs`)
+		- Linux: `/tmp/USERNAME/MyApp-nodejs`
+		*/
+		readonly temp: string;
+	}
+}
+
+declare const envPaths: {
+	/**
+	Get paths for storing things like data, config, cache, etc.
+
+	Note: It only generates the path strings. It doesn't create the directories for you. You could use [`make-dir`](https://github.com/sindresorhus/make-dir) to create the directories.
+
+	@param name - Name of your project. Used to generate the paths.
+	@returns The paths to use for your project on current OS.
+
+	@example
+	```
+	import envPaths = require('env-paths');
+
+	const paths = envPaths('MyApp');
+
+	paths.data;
+	//=> '/home/sindresorhus/.local/share/MyApp-nodejs'
+
+	paths.config
+	//=> '/home/sindresorhus/.config/MyApp-nodejs'
+	```
+	*/
+	(name: string, options?: envPaths.Options): envPaths.Paths;
+
+	// TODO: Remove this for the next major release, refactor the whole definition to:
+	// declare function envPaths(name: string, options?: envPaths.Options): envPaths.Paths;
+	// export = envPaths;
+	default: typeof envPaths;
+};
+
+export = envPaths;
diff --git a/server/node_modules/env-paths/index.js b/server/node_modules/env-paths/index.js
new file mode 100644
index 0000000..7e7b50b
--- /dev/null
+++ b/server/node_modules/env-paths/index.js
@@ -0,0 +1,74 @@
+'use strict';
+const path = require('path');
+const os = require('os');
+
+const homedir = os.homedir();
+const tmpdir = os.tmpdir();
+const {env} = process;
+
+const macos = name => {
+	const library = path.join(homedir, 'Library');
+
+	return {
+		data: path.join(library, 'Application Support', name),
+		config: path.join(library, 'Preferences', name),
+		cache: path.join(library, 'Caches', name),
+		log: path.join(library, 'Logs', name),
+		temp: path.join(tmpdir, name)
+	};
+};
+
+const windows = name => {
+	const appData = env.APPDATA || path.join(homedir, 'AppData', 'Roaming');
+	const localAppData = env.LOCALAPPDATA || path.join(homedir, 'AppData', 'Local');
+
+	return {
+		// Data/config/cache/log are invented by me as Windows isn't opinionated about this
+		data: path.join(localAppData, name, 'Data'),
+		config: path.join(appData, name, 'Config'),
+		cache: path.join(localAppData, name, 'Cache'),
+		log: path.join(localAppData, name, 'Log'),
+		temp: path.join(tmpdir, name)
+	};
+};
+
+// https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
+const linux = name => {
+	const username = path.basename(homedir);
+
+	return {
+		data: path.join(env.XDG_DATA_HOME || path.join(homedir, '.local', 'share'), name),
+		config: path.join(env.XDG_CONFIG_HOME || path.join(homedir, '.config'), name),
+		cache: path.join(env.XDG_CACHE_HOME || path.join(homedir, '.cache'), name),
+		// https://wiki.debian.org/XDGBaseDirectorySpecification#state
+		log: path.join(env.XDG_STATE_HOME || path.join(homedir, '.local', 'state'), name),
+		temp: path.join(tmpdir, username, name)
+	};
+};
+
+const envPaths = (name, options) => {
+	if (typeof name !== 'string') {
+		throw new TypeError(`Expected string, got ${typeof name}`);
+	}
+
+	options = Object.assign({suffix: 'nodejs'}, options);
+
+	if (options.suffix) {
+		// Add suffix to prevent possible conflict with native apps
+		name += `-${options.suffix}`;
+	}
+
+	if (process.platform === 'darwin') {
+		return macos(name);
+	}
+
+	if (process.platform === 'win32') {
+		return windows(name);
+	}
+
+	return linux(name);
+};
+
+module.exports = envPaths;
+// TODO: Remove this for the next major release
+module.exports.default = envPaths;
diff --git a/server/node_modules/env-paths/license b/server/node_modules/env-paths/license
new file mode 100644
index 0000000..e7af2f7
--- /dev/null
+++ b/server/node_modules/env-paths/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/env-paths/package.json b/server/node_modules/env-paths/package.json
new file mode 100644
index 0000000..fae4ebc
--- /dev/null
+++ b/server/node_modules/env-paths/package.json
@@ -0,0 +1,45 @@
+{
+	"name": "env-paths",
+	"version": "2.2.1",
+	"description": "Get paths for storing things like data, config, cache, etc",
+	"license": "MIT",
+	"repository": "sindresorhus/env-paths",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=6"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"common",
+		"user",
+		"paths",
+		"env",
+		"environment",
+		"directory",
+		"dir",
+		"appdir",
+		"path",
+		"data",
+		"config",
+		"cache",
+		"logs",
+		"temp",
+		"linux",
+		"unix"
+	],
+	"devDependencies": {
+		"ava": "^1.4.1",
+		"tsd": "^0.7.1",
+		"xo": "^0.24.0"
+	}
+}
diff --git a/server/node_modules/env-paths/readme.md b/server/node_modules/env-paths/readme.md
new file mode 100644
index 0000000..b66d571
--- /dev/null
+++ b/server/node_modules/env-paths/readme.md
@@ -0,0 +1,115 @@
+# env-paths
+
+> Get paths for storing things like data, config, cache, etc
+
+Uses the correct OS-specific paths. Most developers get this wrong.
+
+
+## Install
+
+```
+$ npm install env-paths
+```
+
+
+## Usage
+
+```js
+const envPaths = require('env-paths');
+
+const paths = envPaths('MyApp');
+
+paths.data;
+//=> '/home/sindresorhus/.local/share/MyApp-nodejs'
+
+paths.config
+//=> '/home/sindresorhus/.config/MyApp-nodejs'
+```
+
+
+## API
+
+### paths = envPaths(name, options?)
+
+Note: It only generates the path strings. It doesn't create the directories for you. You could use [`make-dir`](https://github.com/sindresorhus/make-dir) to create the directories.
+
+#### name
+
+Type: `string`
+
+Name of your project. Used to generate the paths.
+
+#### options
+
+Type: `object`
+
+##### suffix
+
+Type: `string`<br>
+Default: `'nodejs'`
+
+**Don't use this option unless you really have to!**<br>
+Suffix appended to the project name to avoid name conflicts with native
+apps. Pass an empty string to disable it.
+
+### paths.data
+
+Directory for data files.
+
+Example locations (with the default `nodejs` [suffix](#suffix)):
+
+- macOS: `~/Library/Application Support/MyApp-nodejs`
+- Windows: `%LOCALAPPDATA%\MyApp-nodejs\Data` (for example, `C:\Users\USERNAME\AppData\Local\MyApp-nodejs\Data`)
+- Linux: `~/.local/share/MyApp-nodejs` (or `$XDG_DATA_HOME/MyApp-nodejs`)
+
+### paths.config
+
+Directory for config files.
+
+Example locations (with the default `nodejs` [suffix](#suffix)):
+
+- macOS: `~/Library/Preferences/MyApp-nodejs`
+- Windows: `%APPDATA%\MyApp-nodejs\Config` (for example, `C:\Users\USERNAME\AppData\Roaming\MyApp-nodejs\Config`)
+- Linux: `~/.config/MyApp-nodejs` (or `$XDG_CONFIG_HOME/MyApp-nodejs`)
+
+### paths.cache
+
+Directory for non-essential data files.
+
+Example locations (with the default `nodejs` [suffix](#suffix)):
+
+- macOS: `~/Library/Caches/MyApp-nodejs`
+- Windows: `%LOCALAPPDATA%\MyApp-nodejs\Cache` (for example, `C:\Users\USERNAME\AppData\Local\MyApp-nodejs\Cache`)
+- Linux: `~/.cache/MyApp-nodejs` (or `$XDG_CACHE_HOME/MyApp-nodejs`)
+
+### paths.log
+
+Directory for log files.
+
+Example locations (with the default `nodejs` [suffix](#suffix)):
+
+- macOS: `~/Library/Logs/MyApp-nodejs`
+- Windows: `%LOCALAPPDATA%\MyApp-nodejs\Log` (for example, `C:\Users\USERNAME\AppData\Local\MyApp-nodejs\Log`)
+- Linux: `~/.local/state/MyApp-nodejs` (or `$XDG_STATE_HOME/MyApp-nodejs`)
+
+### paths.temp
+
+Directory for temporary files.
+
+Example locations (with the default `nodejs` [suffix](#suffix)):
+
+- macOS: `/var/folders/jf/f2twvvvs5jl_m49tf034ffpw0000gn/T/MyApp-nodejs`
+- Windows: `%LOCALAPPDATA%\Temp\MyApp-nodejs` (for example, `C:\Users\USERNAME\AppData\Local\Temp\MyApp-nodejs`)
+- Linux: `/tmp/USERNAME/MyApp-nodejs`
+
+---
+
+<div align="center">
+	<b>
+		<a href="https://tidelift.com/subscription/pkg/npm-env-paths?utm_source=npm-env-paths&utm_medium=referral&utm_campaign=readme">Get professional support for this package with a Tidelift subscription</a>
+	</b>
+	<br>
+	<sub>
+		Tidelift helps make open source sustainable for maintainers while giving companies<br>assurances about security, maintenance, and licensing for their dependencies.
+	</sub>
+</div>
diff --git a/server/node_modules/err-code/.editorconfig b/server/node_modules/err-code/.editorconfig
new file mode 100644
index 0000000..829280b
--- /dev/null
+++ b/server/node_modules/err-code/.editorconfig
@@ -0,0 +1,12 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[package.json]
+indent_size = 2
diff --git a/server/node_modules/err-code/.eslintrc.json b/server/node_modules/err-code/.eslintrc.json
new file mode 100644
index 0000000..4829595
--- /dev/null
+++ b/server/node_modules/err-code/.eslintrc.json
@@ -0,0 +1,7 @@
+{
+    "root": true,
+    "extends": [
+        "@satazor/eslint-config/es6",
+        "@satazor/eslint-config/addons/node"
+    ]
+}
\ No newline at end of file
diff --git a/server/node_modules/err-code/.travis.yml b/server/node_modules/err-code/.travis.yml
new file mode 100644
index 0000000..b29cf66
--- /dev/null
+++ b/server/node_modules/err-code/.travis.yml
@@ -0,0 +1,4 @@
+language: node_js
+node_js:
+  - "4"
+  - "6"
diff --git a/server/node_modules/err-code/README.md b/server/node_modules/err-code/README.md
new file mode 100644
index 0000000..5afdab0
--- /dev/null
+++ b/server/node_modules/err-code/README.md
@@ -0,0 +1,70 @@
+# err-code
+
+[![NPM version][npm-image]][npm-url] [![Downloads][downloads-image]][npm-url] [![Build Status][travis-image]][travis-url] [![Dependency status][david-dm-image]][david-dm-url] [![Dev Dependency status][david-dm-dev-image]][david-dm-dev-url] [![Greenkeeper badge][greenkeeper-image]][greenkeeper-url]
+
+[npm-url]:https://npmjs.org/package/err-code
+[downloads-image]:http://img.shields.io/npm/dm/err-code.svg
+[npm-image]:http://img.shields.io/npm/v/err-code.svg
+[travis-url]:https://travis-ci.org/IndigoUnited/js-err-code
+[travis-image]:http://img.shields.io/travis/IndigoUnited/js-err-code/master.svg
+[david-dm-url]:https://david-dm.org/IndigoUnited/js-err-code
+[david-dm-image]:https://img.shields.io/david/IndigoUnited/js-err-code.svg
+[david-dm-dev-url]:https://david-dm.org/IndigoUnited/js-err-code?type=dev
+[david-dm-dev-image]:https://img.shields.io/david/dev/IndigoUnited/js-err-code.svg
+[greenkeeper-image]:https://badges.greenkeeper.io/IndigoUnited/js-err-code.svg
+[greenkeeper-url]:https://greenkeeper.io/
+
+Create new error instances with a code and additional properties.
+
+
+## Installation
+
+```console
+$ npm install err-code
+// or
+$ bower install err-code
+```
+
+The browser file is named index.umd.js which supports CommonJS, AMD and globals (errCode).
+
+
+## Why
+
+I find myself doing this repeatedly:
+
+```js
+var err = new Error('My message');
+err.code = 'SOMECODE';
+err.detail = 'Additional information about the error';
+throw err;
+```
+
+
+## Usage
+
+Simple usage.
+
+```js
+var errcode = require('err-code');
+
+// fill error with message + code
+throw errcode(new Error('My message'), 'ESOMECODE');
+// fill error with message + code + props
+throw errcode(new Error('My message'), 'ESOMECODE', { detail: 'Additional information about the error' });
+// fill error with message + props
+throw errcode(new Error('My message'), { detail: 'Additional information about the error' });
+```
+
+## Pre-existing fields
+
+If the passed `Error` already has a `.code` field, or fields specified in the third argument to `errcode` they will be overwritten, unless the fields are read only or otherwise throw during assignment in which case a new object will be created that shares a prototype chain with the original `Error`. The `.stack` and `.message` properties will be carried over from the original error and `.code` or any passed properties will be set on it.
+
+
+## Tests
+
+`$ npm test`
+
+
+## License
+
+Released under the [MIT License](http://www.opensource.org/licenses/mit-license.php).
diff --git a/server/node_modules/err-code/bower.json b/server/node_modules/err-code/bower.json
new file mode 100644
index 0000000..a39cb70
--- /dev/null
+++ b/server/node_modules/err-code/bower.json
@@ -0,0 +1,30 @@
+{
+  "name": "err-code",
+  "version": "1.1.1",
+  "description": "Create new error instances with a code and additional properties",
+  "main": "index.umd.js",
+  "homepage": "https://github.com/IndigoUnited/js-err-code",
+  "authors": [
+    "IndigoUnited <hello@indigounited.com> (http://indigounited.com)"
+  ],
+  "moduleType": [
+    "amd",
+    "globals",
+    "node"
+  ],
+  "keywords": [
+      "error",
+      "err",
+      "code",
+      "properties",
+      "property"
+  ],
+  "license": "MIT",
+  "ignore": [
+    "**/.*",
+    "node_modules",
+    "bower_components",
+    "test",
+    "tests"
+  ]
+}
diff --git a/server/node_modules/err-code/index.js b/server/node_modules/err-code/index.js
new file mode 100644
index 0000000..9ff3e9c
--- /dev/null
+++ b/server/node_modules/err-code/index.js
@@ -0,0 +1,47 @@
+'use strict';
+
+function assign(obj, props) {
+    for (const key in props) {
+        Object.defineProperty(obj, key, {
+            value: props[key],
+            enumerable: true,
+            configurable: true,
+        });
+    }
+
+    return obj;
+}
+
+function createError(err, code, props) {
+    if (!err || typeof err === 'string') {
+        throw new TypeError('Please pass an Error to err-code');
+    }
+
+    if (!props) {
+        props = {};
+    }
+
+    if (typeof code === 'object') {
+        props = code;
+        code = undefined;
+    }
+
+    if (code != null) {
+        props.code = code;
+    }
+
+    try {
+        return assign(err, props);
+    } catch (_) {
+        props.message = err.message;
+        props.stack = err.stack;
+
+        const ErrClass = function () {};
+
+        ErrClass.prototype = Object.create(Object.getPrototypeOf(err));
+
+        return assign(new ErrClass(), props);
+    }
+}
+
+module.exports = createError;
diff --git a/server/node_modules/err-code/index.umd.js b/server/node_modules/err-code/index.umd.js
new file mode 100644
index 0000000..4100726
--- /dev/null
+++ b/server/node_modules/err-code/index.umd.js
@@ -0,0 +1,51 @@
+(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.errCode = f()}})(function(){var define,module,exports;return (function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r})()({1:[function(require,module,exports){
+'use strict';
+
+function assign(obj, props) {
+    for (const key in props) {
+        Object.defineProperty(obj, key, {
+            value: props[key],
+            enumerable: true,
+            configurable: true,
+        });
+    }
+
+    return obj;
+}
+
+function createError(err, code, props) {
+    if (!err || typeof err === 'string') {
+        throw new TypeError('Please pass an Error to err-code');
+    }
+
+    if (!props) {
+        props = {};
+    }
+
+    if (typeof code === 'object') {
+        props = code;
+        code = undefined;
+    }
+
+    if (code != null) {
+        props.code = code;
+    }
+
+    try {
+        return assign(err, props);
+    } catch (_) {
+        props.message = err.message;
+        props.stack = err.stack;
+
+        const ErrClass = function () {};
+
+        ErrClass.prototype = Object.create(Object.getPrototypeOf(err));
+
+        return assign(new ErrClass(), props);
+    }
+}
+
+module.exports = createError;
+
+},{}]},{},[1])(1)
+});
diff --git a/server/node_modules/err-code/package.json b/server/node_modules/err-code/package.json
new file mode 100644
index 0000000..8c6007b
--- /dev/null
+++ b/server/node_modules/err-code/package.json
@@ -0,0 +1,34 @@
+{
+  "name": "err-code",
+  "version": "2.0.3",
+  "description": "Create an error with a code",
+  "main": "index.js",
+  "scripts": {
+    "lint": "eslint '{*.js,test/**/*.js}' --ignore-pattern *.umd.js",
+    "test": "mocha --bail",
+    "browserify": "browserify -s err-code index.js > index.umd.js"
+  },
+  "bugs": {
+    "url": "https://github.com/IndigoUnited/js-err-code/issues/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/IndigoUnited/js-err-code.git"
+  },
+  "keywords": [
+    "error",
+    "err",
+    "code",
+    "properties",
+    "property"
+  ],
+  "author": "IndigoUnited <hello@indigounited.com> (http://indigounited.com)",
+  "license": "MIT",
+  "devDependencies": {
+    "@satazor/eslint-config": "^3.0.0",
+    "browserify": "^16.5.1",
+    "eslint": "^7.2.0",
+    "expect.js": "^0.3.1",
+    "mocha": "^8.0.1"
+  }
+}
diff --git a/server/node_modules/err-code/test/.eslintrc.json b/server/node_modules/err-code/test/.eslintrc.json
new file mode 100644
index 0000000..f9fbb2d
--- /dev/null
+++ b/server/node_modules/err-code/test/.eslintrc.json
@@ -0,0 +1,5 @@
+{
+    "env": {
+        "mocha": true
+    }
+}
\ No newline at end of file
diff --git a/server/node_modules/err-code/test/test.js b/server/node_modules/err-code/test/test.js
new file mode 100644
index 0000000..22ba0a8
--- /dev/null
+++ b/server/node_modules/err-code/test/test.js
@@ -0,0 +1,159 @@
+'use strict';
+
+const errcode = require('../index');
+const expect = require('expect.js');
+
+describe('errcode', () => {
+    describe('string as first argument', () => {
+        it('should throw an error', () => {
+            expect(() => { errcode('my message'); }).to.throwError((err) => {
+                expect(err).to.be.a(TypeError);
+            });
+        });
+    });
+
+    describe('error as first argument', () => {
+        it('should accept an error and do nothing', () => {
+            const myErr = new Error('my message');
+            const err = errcode(myErr);
+
+            expect(err).to.be(myErr);
+            expect(err.hasOwnProperty(err.code)).to.be(false);
+        });
+
+        it('should accept an error and add a code', () => {
+            const myErr = new Error('my message');
+            const err = errcode(myErr, 'ESOME');
+
+            expect(err).to.be(myErr);
+            expect(err.code).to.be('ESOME');
+        });
+
+        it('should accept an error object and add code & properties', () => {
+            const myErr = new Error('my message');
+            const err = errcode(myErr, 'ESOME', { foo: 'bar', bar: 'foo' });
+
+            expect(err).to.be.an(Error);
+            expect(err.code).to.be('ESOME');
+            expect(err.foo).to.be('bar');
+            expect(err.bar).to.be('foo');
+        });
+
+        it('should create an error object without code but with properties', () => {
+            const myErr = new Error('my message');
+            const err = errcode(myErr, { foo: 'bar', bar: 'foo' });
+
+            expect(err).to.be.an(Error);
+            expect(err.code).to.be(undefined);
+            expect(err.foo).to.be('bar');
+            expect(err.bar).to.be('foo');
+        });
+
+        it('should set a non-writable field', () => {
+            const myErr = new Error('my message');
+
+            Object.defineProperty(myErr, 'code', {
+                value: 'derp',
+                writable: false,
+            });
+            const err = errcode(myErr, 'ERR_WAT');
+
+            expect(err).to.be.an(Error);
+            expect(err.stack).to.equal(myErr.stack);
+            expect(err.code).to.be('ERR_WAT');
+        });
+
+        it('should add a code to frozen object', () => {
+            const myErr = new Error('my message');
+            const err = errcode(Object.freeze(myErr), 'ERR_WAT');
+
+            expect(err).to.be.an(Error);
+            expect(err.stack).to.equal(myErr.stack);
+            expect(err.code).to.be('ERR_WAT');
+        });
+
+        it('should to set a field that throws at assignment time', () => {
+            const myErr = new Error('my message');
+
+            Object.defineProperty(myErr, 'code', {
+                enumerable: true,
+                set() {
+                    throw new Error('Nope!');
+                },
+                get() {
+                    return 'derp';
+                },
+            });
+            const err = errcode(myErr, 'ERR_WAT');
+
+            expect(err).to.be.an(Error);
+            expect(err.stack).to.equal(myErr.stack);
+            expect(err.code).to.be('ERR_WAT');
+        });
+
+        it('should retain error type', () => {
+            const myErr = new TypeError('my message');
+
+            Object.defineProperty(myErr, 'code', {
+                value: 'derp',
+                writable: false,
+            });
+            const err = errcode(myErr, 'ERR_WAT');
+
+            expect(err).to.be.a(TypeError);
+            expect(err.stack).to.equal(myErr.stack);
+            expect(err.code).to.be('ERR_WAT');
+        });
+
+        it('should add a code to a class that extends Error', () => {
+            class CustomError extends Error {
+                set code(val) {
+                    throw new Error('Nope!');
+                }
+            }
+
+            const myErr = new CustomError('my message');
+
+            Object.defineProperty(myErr, 'code', {
+                value: 'derp',
+                writable: false,
+                configurable: false,
+            });
+            const err = errcode(myErr, 'ERR_WAT');
+
+            expect(err).to.be.a(CustomError);
+            expect(err.stack).to.equal(myErr.stack);
+            expect(err.code).to.be('ERR_WAT');
+
+            // original prototype chain should be intact
+            expect(() => {
+                const otherErr = new CustomError('my message');
+
+                otherErr.code = 'derp';
+            }).to.throwError();
+        });
+
+        it('should support errors that are not Errors', () => {
+            const err = errcode({
+                message: 'Oh noes!',
+            }, 'ERR_WAT');
+
+            expect(err.message).to.be('Oh noes!');
+            expect(err.code).to.be('ERR_WAT');
+        });
+    });
+
+    describe('falsy first arguments', () => {
+        it('should not allow passing null as the first argument', () => {
+            expect(() => { errcode(null); }).to.throwError((err) => {
+                expect(err).to.be.a(TypeError);
+            });
+        });
+
+        it('should not allow passing undefined as the first argument', () => {
+            expect(() => { errcode(undefined); }).to.throwError((err) => {
+                expect(err).to.be.a(TypeError);
+            });
+        });
+    });
+});
diff --git a/server/node_modules/es-define-property/.eslintrc b/server/node_modules/es-define-property/.eslintrc
new file mode 100644
index 0000000..46f3b12
--- /dev/null
+++ b/server/node_modules/es-define-property/.eslintrc
@@ -0,0 +1,13 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"new-cap": ["error", {
+			"capIsNewExceptions": [
+				"GetIntrinsic",
+			],
+		}],
+	},
+}
diff --git a/server/node_modules/es-define-property/.github/FUNDING.yml b/server/node_modules/es-define-property/.github/FUNDING.yml
new file mode 100644
index 0000000..4445451
--- /dev/null
+++ b/server/node_modules/es-define-property/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/es-define-property
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with a single custom sponsorship URL
diff --git a/server/node_modules/es-define-property/.nycrc b/server/node_modules/es-define-property/.nycrc
new file mode 100644
index 0000000..bdd626c
--- /dev/null
+++ b/server/node_modules/es-define-property/.nycrc
@@ -0,0 +1,9 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/es-define-property/CHANGELOG.md b/server/node_modules/es-define-property/CHANGELOG.md
new file mode 100644
index 0000000..5f60cc0
--- /dev/null
+++ b/server/node_modules/es-define-property/CHANGELOG.md
@@ -0,0 +1,29 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.0.1](https://github.com/ljharb/es-define-property/compare/v1.0.0...v1.0.1) - 2024-12-06
+
+### Commits
+
+- [types] use shared tsconfig [`954a663`](https://github.com/ljharb/es-define-property/commit/954a66360326e508a0e5daa4b07493d58f5e110e)
+- [actions] split out node 10-20, and 20+ [`3a8e84b`](https://github.com/ljharb/es-define-property/commit/3a8e84b23883f26ff37b3e82ff283834228e18c6)
+- [Dev Deps] update `@ljharb/eslint-config`, `@ljharb/tsconfig`, `@types/get-intrinsic`, `@types/tape`, `auto-changelog`, `gopd`, `tape` [`86ae27b`](https://github.com/ljharb/es-define-property/commit/86ae27bb8cc857b23885136fad9cbe965ae36612)
+- [Refactor] avoid using `get-intrinsic` [`02480c0`](https://github.com/ljharb/es-define-property/commit/02480c0353ef6118965282977c3864aff53d98b1)
+- [Tests] replace `aud` with `npm audit` [`f6093ff`](https://github.com/ljharb/es-define-property/commit/f6093ff74ab51c98015c2592cd393bd42478e773)
+- [Tests] configure testling [`7139e66`](https://github.com/ljharb/es-define-property/commit/7139e66959247a56086d9977359caef27c6849e7)
+- [Dev Deps] update `tape` [`b901b51`](https://github.com/ljharb/es-define-property/commit/b901b511a75e001a40ce1a59fef7d9ffcfc87482)
+- [Tests] fix types in tests [`469d269`](https://github.com/ljharb/es-define-property/commit/469d269fd141b1e773ec053a9fa35843493583e0)
+- [Dev Deps] add missing peer dep [`733acfb`](https://github.com/ljharb/es-define-property/commit/733acfb0c4c96edf337e470b89a25a5b3724c352)
+
+## v1.0.0 - 2024-02-12
+
+### Commits
+
+- Initial implementation, tests, readme, types [`3e154e1`](https://github.com/ljharb/es-define-property/commit/3e154e11a2fee09127220f5e503bf2c0a31dd480)
+- Initial commit [`07d98de`](https://github.com/ljharb/es-define-property/commit/07d98de34a4dc31ff5e83a37c0c3f49e0d85cd50)
+- npm init [`c4eb634`](https://github.com/ljharb/es-define-property/commit/c4eb6348b0d3886aac36cef34ad2ee0665ea6f3e)
+- Only apps should have lockfiles [`7af86ec`](https://github.com/ljharb/es-define-property/commit/7af86ec1d311ec0b17fdfe616a25f64276903856)
diff --git a/server/node_modules/es-define-property/LICENSE b/server/node_modules/es-define-property/LICENSE
new file mode 100644
index 0000000..f82f389
--- /dev/null
+++ b/server/node_modules/es-define-property/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/es-define-property/README.md b/server/node_modules/es-define-property/README.md
new file mode 100644
index 0000000..9b291bd
--- /dev/null
+++ b/server/node_modules/es-define-property/README.md
@@ -0,0 +1,49 @@
+# es-define-property <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+`Object.defineProperty`, but not IE 8's broken one.
+
+## Example
+
+```js
+const assert = require('assert');
+
+const $defineProperty = require('es-define-property');
+
+if ($defineProperty) {
+    assert.equal($defineProperty, Object.defineProperty);
+} else if (Object.defineProperty) {
+    assert.equal($defineProperty, false, 'this is IE 8');
+} else {
+    assert.equal($defineProperty, false, 'this is an ES3 engine');
+}
+```
+
+## Tests
+Simply clone the repo, `npm install`, and run `npm test`
+
+## Security
+
+Please email [@ljharb](https://github.com/ljharb) or see https://tidelift.com/security if you have a potential security vulnerability to report.
+
+[package-url]: https://npmjs.org/package/es-define-property
+[npm-version-svg]: https://versionbadg.es/ljharb/es-define-property.svg
+[deps-svg]: https://david-dm.org/ljharb/es-define-property.svg
+[deps-url]: https://david-dm.org/ljharb/es-define-property
+[dev-deps-svg]: https://david-dm.org/ljharb/es-define-property/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/es-define-property#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/es-define-property.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/es-define-property.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/es-define-property.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=es-define-property
+[codecov-image]: https://codecov.io/gh/ljharb/es-define-property/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/es-define-property/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/es-define-property
+[actions-url]: https://github.com/ljharb/es-define-property/actions
diff --git a/server/node_modules/es-define-property/index.d.ts b/server/node_modules/es-define-property/index.d.ts
new file mode 100644
index 0000000..6012247
--- /dev/null
+++ b/server/node_modules/es-define-property/index.d.ts
@@ -0,0 +1,3 @@
+declare const defineProperty: false | typeof Object.defineProperty;
+
+export = defineProperty;
\ No newline at end of file
diff --git a/server/node_modules/es-define-property/index.js b/server/node_modules/es-define-property/index.js
new file mode 100644
index 0000000..e0a2925
--- /dev/null
+++ b/server/node_modules/es-define-property/index.js
@@ -0,0 +1,14 @@
+'use strict';
+
+/** @type {import('.')} */
+var $defineProperty = Object.defineProperty || false;
+if ($defineProperty) {
+	try {
+		$defineProperty({}, 'a', { value: 1 });
+	} catch (e) {
+		// IE 8 has a broken defineProperty
+		$defineProperty = false;
+	}
+}
+
+module.exports = $defineProperty;
diff --git a/server/node_modules/es-define-property/package.json b/server/node_modules/es-define-property/package.json
new file mode 100644
index 0000000..fbed187
--- /dev/null
+++ b/server/node_modules/es-define-property/package.json
@@ -0,0 +1,81 @@
+{
+	"name": "es-define-property",
+	"version": "1.0.1",
+	"description": "`Object.defineProperty`, but not IE 8's broken one.",
+	"main": "index.js",
+	"types": "./index.d.ts",
+	"exports": {
+		".": "./index.js",
+		"./package.json": "./package.json"
+	},
+	"sideEffects": false,
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prepublishOnly": "safe-publish-latest",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc -p .",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>= 10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/es-define-property.git"
+	},
+	"keywords": [
+		"javascript",
+		"ecmascript",
+		"object",
+		"define",
+		"property",
+		"defineProperty",
+		"Object.defineProperty"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/es-define-property/issues"
+	},
+	"homepage": "https://github.com/ljharb/es-define-property#readme",
+	"devDependencies": {
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.2",
+		"@types/gopd": "^1.0.3",
+		"@types/tape": "^5.6.5",
+		"auto-changelog": "^2.5.0",
+		"encoding": "^0.1.13",
+		"eslint": "^8.8.0",
+		"evalmd": "^0.0.19",
+		"gopd": "^1.2.0",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"engines": {
+		"node": ">= 0.4"
+	},
+	"testling": {
+		"files": "test/index.js"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	}
+}
diff --git a/server/node_modules/es-define-property/test/index.js b/server/node_modules/es-define-property/test/index.js
new file mode 100644
index 0000000..b4b4688
--- /dev/null
+++ b/server/node_modules/es-define-property/test/index.js
@@ -0,0 +1,56 @@
+'use strict';
+
+var $defineProperty = require('../');
+
+var test = require('tape');
+var gOPD = require('gopd');
+
+test('defineProperty: supported', { skip: !$defineProperty }, function (t) {
+	t.plan(4);
+
+	t.equal(typeof $defineProperty, 'function', 'defineProperty is supported');
+	if ($defineProperty && gOPD) { // this `if` check is just to shut TS up
+		/** @type {{ a: number, b?: number, c?: number }} */
+		var o = { a: 1 };
+
+		$defineProperty(o, 'b', { enumerable: true, value: 2 });
+		t.deepEqual(
+			gOPD(o, 'b'),
+			{
+				configurable: false,
+				enumerable: true,
+				value: 2,
+				writable: false
+			},
+			'property descriptor is as expected'
+		);
+
+		$defineProperty(o, 'c', { enumerable: false, value: 3, writable: true });
+		t.deepEqual(
+			gOPD(o, 'c'),
+			{
+				configurable: false,
+				enumerable: false,
+				value: 3,
+				writable: true
+			},
+			'property descriptor is as expected'
+		);
+	}
+
+	t.equal($defineProperty, Object.defineProperty, 'defineProperty is Object.defineProperty');
+
+	t.end();
+});
+
+test('defineProperty: not supported', { skip: !!$defineProperty }, function (t) {
+	t.notOk($defineProperty, 'defineProperty is not supported');
+
+	t.match(
+		typeof $defineProperty,
+		/^(?:undefined|boolean)$/,
+		'`typeof defineProperty` is `undefined` or `boolean`'
+	);
+
+	t.end();
+});
diff --git a/server/node_modules/es-define-property/tsconfig.json b/server/node_modules/es-define-property/tsconfig.json
new file mode 100644
index 0000000..5a49992
--- /dev/null
+++ b/server/node_modules/es-define-property/tsconfig.json
@@ -0,0 +1,10 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "es2022",
+	},
+	"exclude": [
+		"coverage",
+		"test/list-exports"
+	],
+}
diff --git a/server/node_modules/es-errors/.eslintrc b/server/node_modules/es-errors/.eslintrc
new file mode 100644
index 0000000..3b5d9e9
--- /dev/null
+++ b/server/node_modules/es-errors/.eslintrc
@@ -0,0 +1,5 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+}
diff --git a/server/node_modules/es-errors/.github/FUNDING.yml b/server/node_modules/es-errors/.github/FUNDING.yml
new file mode 100644
index 0000000..f1b8805
--- /dev/null
+++ b/server/node_modules/es-errors/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/es-errors
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with a single custom sponsorship URL
diff --git a/server/node_modules/es-errors/CHANGELOG.md b/server/node_modules/es-errors/CHANGELOG.md
new file mode 100644
index 0000000..204a9e9
--- /dev/null
+++ b/server/node_modules/es-errors/CHANGELOG.md
@@ -0,0 +1,40 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.3.0](https://github.com/ljharb/es-errors/compare/v1.2.1...v1.3.0) - 2024-02-05
+
+### Commits
+
+- [New] add `EvalError` and `URIError` [`1927627`](https://github.com/ljharb/es-errors/commit/1927627ba68cb6c829d307231376c967db53acdf)
+
+## [v1.2.1](https://github.com/ljharb/es-errors/compare/v1.2.0...v1.2.1) - 2024-02-04
+
+### Commits
+
+- [Fix] add missing `exports` entry [`5bb5f28`](https://github.com/ljharb/es-errors/commit/5bb5f280f98922701109d6ebb82eea2257cecc7e)
+
+## [v1.2.0](https://github.com/ljharb/es-errors/compare/v1.1.0...v1.2.0) - 2024-02-04
+
+### Commits
+
+- [New] add `ReferenceError` [`6d8cf5b`](https://github.com/ljharb/es-errors/commit/6d8cf5bbb6f3f598d02cf6f30e468ba2caa8e143)
+
+## [v1.1.0](https://github.com/ljharb/es-errors/compare/v1.0.0...v1.1.0) - 2024-02-04
+
+### Commits
+
+- [New] add base Error [`2983ab6`](https://github.com/ljharb/es-errors/commit/2983ab65f7bc5441276cb021dc3aa03c78881698)
+
+## v1.0.0 - 2024-02-03
+
+### Commits
+
+- Initial implementation, tests, readme, type [`8f47631`](https://github.com/ljharb/es-errors/commit/8f476317e9ad76f40ad648081829b1a1a3a1288b)
+- Initial commit [`ea5d099`](https://github.com/ljharb/es-errors/commit/ea5d099ef18e550509ab9e2be000526afd81c385)
+- npm init [`6f5ebf9`](https://github.com/ljharb/es-errors/commit/6f5ebf9cead474dadd72b9e63dad315820a089ae)
+- Only apps should have lockfiles [`e1a0aeb`](https://github.com/ljharb/es-errors/commit/e1a0aeb7b80f5cfc56be54d6b2100e915d47def8)
+- [meta] add `sideEffects` flag [`a9c7d46`](https://github.com/ljharb/es-errors/commit/a9c7d460a492f1d8a241c836bc25a322a19cc043)
diff --git a/server/node_modules/es-errors/LICENSE b/server/node_modules/es-errors/LICENSE
new file mode 100644
index 0000000..f82f389
--- /dev/null
+++ b/server/node_modules/es-errors/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/es-errors/README.md b/server/node_modules/es-errors/README.md
new file mode 100644
index 0000000..8dbfacf
--- /dev/null
+++ b/server/node_modules/es-errors/README.md
@@ -0,0 +1,55 @@
+# es-errors <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+A simple cache for a few of the JS Error constructors.
+
+## Example
+
+```js
+const assert = require('assert');
+
+const Base = require('es-errors');
+const Eval = require('es-errors/eval');
+const Range = require('es-errors/range');
+const Ref = require('es-errors/ref');
+const Syntax = require('es-errors/syntax');
+const Type = require('es-errors/type');
+const URI = require('es-errors/uri');
+
+assert.equal(Base, Error);
+assert.equal(Eval, EvalError);
+assert.equal(Range, RangeError);
+assert.equal(Ref, ReferenceError);
+assert.equal(Syntax, SyntaxError);
+assert.equal(Type, TypeError);
+assert.equal(URI, URIError);
+```
+
+## Tests
+Simply clone the repo, `npm install`, and run `npm test`
+
+## Security
+
+Please email [@ljharb](https://github.com/ljharb) or see https://tidelift.com/security if you have a potential security vulnerability to report.
+
+[package-url]: https://npmjs.org/package/es-errors
+[npm-version-svg]: https://versionbadg.es/ljharb/es-errors.svg
+[deps-svg]: https://david-dm.org/ljharb/es-errors.svg
+[deps-url]: https://david-dm.org/ljharb/es-errors
+[dev-deps-svg]: https://david-dm.org/ljharb/es-errors/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/es-errors#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/es-errors.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/es-errors.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/es-errors.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=es-errors
+[codecov-image]: https://codecov.io/gh/ljharb/es-errors/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/es-errors/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/es-errors
+[actions-url]: https://github.com/ljharb/es-errors/actions
diff --git a/server/node_modules/es-errors/eval.d.ts b/server/node_modules/es-errors/eval.d.ts
new file mode 100644
index 0000000..e4210e0
--- /dev/null
+++ b/server/node_modules/es-errors/eval.d.ts
@@ -0,0 +1,3 @@
+declare const EvalError: EvalErrorConstructor;
+
+export = EvalError;
diff --git a/server/node_modules/es-errors/eval.js b/server/node_modules/es-errors/eval.js
new file mode 100644
index 0000000..725ccb6
--- /dev/null
+++ b/server/node_modules/es-errors/eval.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./eval')} */
+module.exports = EvalError;
diff --git a/server/node_modules/es-errors/index.d.ts b/server/node_modules/es-errors/index.d.ts
new file mode 100644
index 0000000..69bdbc9
--- /dev/null
+++ b/server/node_modules/es-errors/index.d.ts
@@ -0,0 +1,3 @@
+declare const Error: ErrorConstructor;
+
+export = Error;
diff --git a/server/node_modules/es-errors/index.js b/server/node_modules/es-errors/index.js
new file mode 100644
index 0000000..cc0c521
--- /dev/null
+++ b/server/node_modules/es-errors/index.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('.')} */
+module.exports = Error;
diff --git a/server/node_modules/es-errors/package.json b/server/node_modules/es-errors/package.json
new file mode 100644
index 0000000..ff8c2a5
--- /dev/null
+++ b/server/node_modules/es-errors/package.json
@@ -0,0 +1,80 @@
+{
+	"name": "es-errors",
+	"version": "1.3.0",
+	"description": "A simple cache for a few of the JS Error constructors.",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./eval": "./eval.js",
+		"./range": "./range.js",
+		"./ref": "./ref.js",
+		"./syntax": "./syntax.js",
+		"./type": "./type.js",
+		"./uri": "./uri.js",
+		"./package.json": "./package.json"
+	},
+	"sideEffects": false,
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"pretest": "npm run lint",
+		"test": "npm run tests-only",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"posttest": "aud --production",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc -p . && eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git' | grep -v dist/)",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/es-errors.git"
+	},
+	"keywords": [
+		"javascript",
+		"ecmascript",
+		"error",
+		"typeerror",
+		"syntaxerror",
+		"rangeerror"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/es-errors/issues"
+	},
+	"homepage": "https://github.com/ljharb/es-errors#readme",
+	"devDependencies": {
+		"@ljharb/eslint-config": "^21.1.0",
+		"@types/tape": "^5.6.4",
+		"aud": "^2.0.4",
+		"auto-changelog": "^2.4.0",
+		"eclint": "^2.8.1",
+		"eslint": "^8.8.0",
+		"evalmd": "^0.0.19",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.7.4",
+		"typescript": "next"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/es-errors/range.d.ts b/server/node_modules/es-errors/range.d.ts
new file mode 100644
index 0000000..3a12e86
--- /dev/null
+++ b/server/node_modules/es-errors/range.d.ts
@@ -0,0 +1,3 @@
+declare const RangeError: RangeErrorConstructor;
+
+export = RangeError;
diff --git a/server/node_modules/es-errors/range.js b/server/node_modules/es-errors/range.js
new file mode 100644
index 0000000..2044fe0
--- /dev/null
+++ b/server/node_modules/es-errors/range.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./range')} */
+module.exports = RangeError;
diff --git a/server/node_modules/es-errors/ref.d.ts b/server/node_modules/es-errors/ref.d.ts
new file mode 100644
index 0000000..a13107e
--- /dev/null
+++ b/server/node_modules/es-errors/ref.d.ts
@@ -0,0 +1,3 @@
+declare const ReferenceError: ReferenceErrorConstructor;
+
+export = ReferenceError;
diff --git a/server/node_modules/es-errors/ref.js b/server/node_modules/es-errors/ref.js
new file mode 100644
index 0000000..d7c430f
--- /dev/null
+++ b/server/node_modules/es-errors/ref.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./ref')} */
+module.exports = ReferenceError;
diff --git a/server/node_modules/es-errors/syntax.d.ts b/server/node_modules/es-errors/syntax.d.ts
new file mode 100644
index 0000000..6a0c53c
--- /dev/null
+++ b/server/node_modules/es-errors/syntax.d.ts
@@ -0,0 +1,3 @@
+declare const SyntaxError: SyntaxErrorConstructor;
+
+export = SyntaxError;
diff --git a/server/node_modules/es-errors/syntax.js b/server/node_modules/es-errors/syntax.js
new file mode 100644
index 0000000..5f5fdde
--- /dev/null
+++ b/server/node_modules/es-errors/syntax.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./syntax')} */
+module.exports = SyntaxError;
diff --git a/server/node_modules/es-errors/test/index.js b/server/node_modules/es-errors/test/index.js
new file mode 100644
index 0000000..1ff0277
--- /dev/null
+++ b/server/node_modules/es-errors/test/index.js
@@ -0,0 +1,19 @@
+'use strict';
+
+var test = require('tape');
+
+var E = require('../');
+var R = require('../range');
+var Ref = require('../ref');
+var S = require('../syntax');
+var T = require('../type');
+
+test('errors', function (t) {
+	t.equal(E, Error);
+	t.equal(R, RangeError);
+	t.equal(Ref, ReferenceError);
+	t.equal(S, SyntaxError);
+	t.equal(T, TypeError);
+
+	t.end();
+});
diff --git a/server/node_modules/es-errors/tsconfig.json b/server/node_modules/es-errors/tsconfig.json
new file mode 100644
index 0000000..99dfeb6
--- /dev/null
+++ b/server/node_modules/es-errors/tsconfig.json
@@ -0,0 +1,49 @@
+{
+	"compilerOptions": {
+		/* Visit https://aka.ms/tsconfig.json to read more about this file */
+
+		/* Projects */
+
+		/* Language and Environment */
+		"target": "es5",																	/* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
+		// "lib": [],																				/* Specify a set of bundled library declaration files that describe the target runtime environment. */
+		// "noLib": true,																		/* Disable including any library files, including the default lib.d.ts. */
+		"useDefineForClassFields": true,										 /* Emit ECMAScript-standard-compliant class fields. */
+		// "moduleDetection": "auto",												/* Control what method is used to detect module-format JS files. */
+
+		/* Modules */
+		"module": "commonjs",																/* Specify what module code is generated. */
+		// "rootDir": "./",																	/* Specify the root folder within your source files. */
+		// "moduleResolution": "node",											 /* Specify how TypeScript looks up a file from a given module specifier. */
+		// "baseUrl": "./",																	/* Specify the base directory to resolve non-relative module names. */
+		// "paths": {},																			/* Specify a set of entries that re-map imports to additional lookup locations. */
+		// "rootDirs": [],																	 /* Allow multiple folders to be treated as one when resolving modules. */
+		// "typeRoots": ["types"],													 /* Specify multiple folders that act like `./node_modules/@types`. */
+		"resolveJsonModule": true,													 /* Enable importing .json files. */
+		// "allowArbitraryExtensions": true,								 /* Enable importing files with any extension, provided a declaration file is present. */
+
+		/* JavaScript Support */
+		"allowJs": true,																		 /* Allow JavaScript files to be a part of your program. Use the `checkJS` option to get errors from these files. */
+		"checkJs": true,																		 /* Enable error reporting in type-checked JavaScript files. */
+		"maxNodeModuleJsDepth": 1,													 /* Specify the maximum folder depth used for checking JavaScript files from `node_modules`. Only applicable with `allowJs`. */
+
+		/* Emit */
+		"declaration": true,																 /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
+		"declarationMap": true,															/* Create sourcemaps for d.ts files. */
+		"noEmit": true,																			/* Disable emitting files from a compilation. */
+
+		/* Interop Constraints */
+		"allowSyntheticDefaultImports": true,								/* Allow `import x from y` when a module doesn't have a default export. */
+		"esModuleInterop": true,														 /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables `allowSyntheticDefaultImports` for type compatibility. */
+		"forceConsistentCasingInFileNames": true,						/* Ensure that casing is correct in imports. */
+
+		/* Type Checking */
+		"strict": true,																			/* Enable all strict type-checking options. */
+
+		/* Completeness */
+		// "skipLibCheck": true															/* Skip type checking all .d.ts files. */
+	},
+	"exclude": [
+		"coverage",
+	],
+}
diff --git a/server/node_modules/es-errors/type.d.ts b/server/node_modules/es-errors/type.d.ts
new file mode 100644
index 0000000..576fb51
--- /dev/null
+++ b/server/node_modules/es-errors/type.d.ts
@@ -0,0 +1,3 @@
+declare const TypeError: TypeErrorConstructor
+
+export = TypeError;
diff --git a/server/node_modules/es-errors/type.js b/server/node_modules/es-errors/type.js
new file mode 100644
index 0000000..9769e44
--- /dev/null
+++ b/server/node_modules/es-errors/type.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./type')} */
+module.exports = TypeError;
diff --git a/server/node_modules/es-errors/uri.d.ts b/server/node_modules/es-errors/uri.d.ts
new file mode 100644
index 0000000..c3261c9
--- /dev/null
+++ b/server/node_modules/es-errors/uri.d.ts
@@ -0,0 +1,3 @@
+declare const URIError: URIErrorConstructor;
+
+export = URIError;
diff --git a/server/node_modules/es-errors/uri.js b/server/node_modules/es-errors/uri.js
new file mode 100644
index 0000000..e9cd1c7
--- /dev/null
+++ b/server/node_modules/es-errors/uri.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./uri')} */
+module.exports = URIError;
diff --git a/server/node_modules/es-object-atoms/.eslintrc b/server/node_modules/es-object-atoms/.eslintrc
new file mode 100644
index 0000000..d90a1bc
--- /dev/null
+++ b/server/node_modules/es-object-atoms/.eslintrc
@@ -0,0 +1,16 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"eqeqeq": ["error", "allow-null"],
+		"id-length": "off",
+		"new-cap": ["error", {
+			"capIsNewExceptions": [
+				"RequireObjectCoercible",
+				"ToObject",
+			],
+		}],
+	},
+}
diff --git a/server/node_modules/es-object-atoms/.github/FUNDING.yml b/server/node_modules/es-object-atoms/.github/FUNDING.yml
new file mode 100644
index 0000000..352bfda
--- /dev/null
+++ b/server/node_modules/es-object-atoms/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/es-object
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with a single custom sponsorship URL
diff --git a/server/node_modules/es-object-atoms/CHANGELOG.md b/server/node_modules/es-object-atoms/CHANGELOG.md
new file mode 100644
index 0000000..fdd2abe
--- /dev/null
+++ b/server/node_modules/es-object-atoms/CHANGELOG.md
@@ -0,0 +1,37 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.1.1](https://github.com/ljharb/es-object-atoms/compare/v1.1.0...v1.1.1) - 2025-01-14
+
+### Commits
+
+- [types] `ToObject`: improve types [`cfe8c8a`](https://github.com/ljharb/es-object-atoms/commit/cfe8c8a105c44820cb22e26f62d12ef0ad9715c8)
+
+## [v1.1.0](https://github.com/ljharb/es-object-atoms/compare/v1.0.1...v1.1.0) - 2025-01-14
+
+### Commits
+
+- [New] add `isObject` [`51e4042`](https://github.com/ljharb/es-object-atoms/commit/51e4042df722eb3165f40dc5f4bf33d0197ecb07)
+
+## [v1.0.1](https://github.com/ljharb/es-object-atoms/compare/v1.0.0...v1.0.1) - 2025-01-13
+
+### Commits
+
+- [Dev Deps] update `@ljharb/eslint-config`, `@ljharb/tsconfig`, `@types/tape`, `auto-changelog`, `tape` [`38ab9eb`](https://github.com/ljharb/es-object-atoms/commit/38ab9eb00b62c2f4668644f5e513d9b414ebd595)
+- [types] improve types [`7d1beb8`](https://github.com/ljharb/es-object-atoms/commit/7d1beb887958b78b6a728a210a1c8370ab7e2aa1)
+- [Tests] replace `aud` with `npm audit` [`25863ba`](https://github.com/ljharb/es-object-atoms/commit/25863baf99178f1d1ad33d1120498db28631907e)
+- [Dev Deps] add missing peer dep [`c012309`](https://github.com/ljharb/es-object-atoms/commit/c0123091287e6132d6f4240496340c427433df28)
+
+## v1.0.0 - 2024-03-16
+
+### Commits
+
+- Initial implementation, tests, readme, types [`f1499db`](https://github.com/ljharb/es-object-atoms/commit/f1499db7d3e1741e64979c61d645ab3137705e82)
+- Initial commit [`99eedc7`](https://github.com/ljharb/es-object-atoms/commit/99eedc7b5fde38a50a28d3c8b724706e3e4c5f6a)
+- [meta] rename repo [`fc851fa`](https://github.com/ljharb/es-object-atoms/commit/fc851fa70616d2d182aaf0bd02c2ed7084dea8fa)
+- npm init [`b909377`](https://github.com/ljharb/es-object-atoms/commit/b909377c50049bd0ec575562d20b0f9ebae8947f)
+- Only apps should have lockfiles [`7249edd`](https://github.com/ljharb/es-object-atoms/commit/7249edd2178c1b9ddfc66ffcc6d07fdf0d28efc1)
diff --git a/server/node_modules/es-object-atoms/LICENSE b/server/node_modules/es-object-atoms/LICENSE
new file mode 100644
index 0000000..f82f389
--- /dev/null
+++ b/server/node_modules/es-object-atoms/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/es-object-atoms/README.md b/server/node_modules/es-object-atoms/README.md
new file mode 100644
index 0000000..447695b
--- /dev/null
+++ b/server/node_modules/es-object-atoms/README.md
@@ -0,0 +1,63 @@
+# es-object-atoms <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+ES Object-related atoms: Object, ToObject, RequireObjectCoercible.
+
+## Example
+
+```js
+const assert = require('assert');
+
+const $Object = require('es-object-atoms');
+const isObject = require('es-object-atoms/isObject');
+const ToObject = require('es-object-atoms/ToObject');
+const RequireObjectCoercible = require('es-object-atoms/RequireObjectCoercible');
+
+assert.equal($Object, Object);
+assert.throws(() => ToObject(null), TypeError);
+assert.throws(() => ToObject(undefined), TypeError);
+assert.throws(() => RequireObjectCoercible(null), TypeError);
+assert.throws(() => RequireObjectCoercible(undefined), TypeError);
+
+assert.equal(isObject(undefined), false);
+assert.equal(isObject(null), false);
+assert.equal(isObject({}), true);
+assert.equal(isObject([]), true);
+assert.equal(isObject(function () {}), true);
+
+assert.deepEqual(RequireObjectCoercible(true), true);
+assert.deepEqual(ToObject(true), Object(true));
+
+const obj = {};
+assert.equal(RequireObjectCoercible(obj), obj);
+assert.equal(ToObject(obj), obj);
+```
+
+## Tests
+Simply clone the repo, `npm install`, and run `npm test`
+
+## Security
+
+Please email [@ljharb](https://github.com/ljharb) or see https://tidelift.com/security if you have a potential security vulnerability to report.
+
+[package-url]: https://npmjs.org/package/es-object-atoms
+[npm-version-svg]: https://versionbadg.es/ljharb/es-object-atoms.svg
+[deps-svg]: https://david-dm.org/ljharb/es-object-atoms.svg
+[deps-url]: https://david-dm.org/ljharb/es-object-atoms
+[dev-deps-svg]: https://david-dm.org/ljharb/es-object-atoms/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/es-object-atoms#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/es-object-atoms.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/es-object-atoms.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/es-object.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=es-object-atoms
+[codecov-image]: https://codecov.io/gh/ljharb/es-object-atoms/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/es-object-atoms/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/es-object-atoms
+[actions-url]: https://github.com/ljharb/es-object-atoms/actions
diff --git a/server/node_modules/es-object-atoms/RequireObjectCoercible.d.ts b/server/node_modules/es-object-atoms/RequireObjectCoercible.d.ts
new file mode 100644
index 0000000..7e26c45
--- /dev/null
+++ b/server/node_modules/es-object-atoms/RequireObjectCoercible.d.ts
@@ -0,0 +1,3 @@
+declare function RequireObjectCoercible<T extends {}>(value: T, optMessage?: string): T;
+
+export = RequireObjectCoercible;
diff --git a/server/node_modules/es-object-atoms/RequireObjectCoercible.js b/server/node_modules/es-object-atoms/RequireObjectCoercible.js
new file mode 100644
index 0000000..8e191c6
--- /dev/null
+++ b/server/node_modules/es-object-atoms/RequireObjectCoercible.js
@@ -0,0 +1,11 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+
+/** @type {import('./RequireObjectCoercible')} */
+module.exports = function RequireObjectCoercible(value) {
+	if (value == null) {
+		throw new $TypeError((arguments.length > 0 && arguments[1]) || ('Cannot call method on ' + value));
+	}
+	return value;
+};
diff --git a/server/node_modules/es-object-atoms/ToObject.d.ts b/server/node_modules/es-object-atoms/ToObject.d.ts
new file mode 100644
index 0000000..d6dd302
--- /dev/null
+++ b/server/node_modules/es-object-atoms/ToObject.d.ts
@@ -0,0 +1,7 @@
+declare function ToObject<T extends object>(value: number): Number;
+declare function ToObject<T extends object>(value: boolean): Boolean;
+declare function ToObject<T extends object>(value: string): String;
+declare function ToObject<T extends object>(value: bigint): BigInt;
+declare function ToObject<T extends object>(value: T): T;
+
+export = ToObject;
diff --git a/server/node_modules/es-object-atoms/ToObject.js b/server/node_modules/es-object-atoms/ToObject.js
new file mode 100644
index 0000000..2b99a7d
--- /dev/null
+++ b/server/node_modules/es-object-atoms/ToObject.js
@@ -0,0 +1,10 @@
+'use strict';
+
+var $Object = require('./');
+var RequireObjectCoercible = require('./RequireObjectCoercible');
+
+/** @type {import('./ToObject')} */
+module.exports = function ToObject(value) {
+	RequireObjectCoercible(value);
+	return $Object(value);
+};
diff --git a/server/node_modules/es-object-atoms/index.d.ts b/server/node_modules/es-object-atoms/index.d.ts
new file mode 100644
index 0000000..8bdbfc8
--- /dev/null
+++ b/server/node_modules/es-object-atoms/index.d.ts
@@ -0,0 +1,3 @@
+declare const Object: ObjectConstructor;
+
+export = Object;
diff --git a/server/node_modules/es-object-atoms/index.js b/server/node_modules/es-object-atoms/index.js
new file mode 100644
index 0000000..1d33cef
--- /dev/null
+++ b/server/node_modules/es-object-atoms/index.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('.')} */
+module.exports = Object;
diff --git a/server/node_modules/es-object-atoms/isObject.d.ts b/server/node_modules/es-object-atoms/isObject.d.ts
new file mode 100644
index 0000000..43bee3b
--- /dev/null
+++ b/server/node_modules/es-object-atoms/isObject.d.ts
@@ -0,0 +1,3 @@
+declare function isObject(x: unknown): x is object;
+
+export = isObject;
diff --git a/server/node_modules/es-object-atoms/isObject.js b/server/node_modules/es-object-atoms/isObject.js
new file mode 100644
index 0000000..ec49bf1
--- /dev/null
+++ b/server/node_modules/es-object-atoms/isObject.js
@@ -0,0 +1,6 @@
+'use strict';
+
+/** @type {import('./isObject')} */
+module.exports = function isObject(x) {
+	return !!x && (typeof x === 'function' || typeof x === 'object');
+};
diff --git a/server/node_modules/es-object-atoms/package.json b/server/node_modules/es-object-atoms/package.json
new file mode 100644
index 0000000..f4cec71
--- /dev/null
+++ b/server/node_modules/es-object-atoms/package.json
@@ -0,0 +1,80 @@
+{
+	"name": "es-object-atoms",
+	"version": "1.1.1",
+	"description": "ES Object-related atoms: Object, ToObject, RequireObjectCoercible",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./RequireObjectCoercible": "./RequireObjectCoercible.js",
+		"./isObject": "./isObject.js",
+		"./ToObject": "./ToObject.js",
+		"./package.json": "./package.json"
+	},
+	"sideEffects": false,
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"pretest": "npm run lint",
+		"test": "npm run tests-only",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"posttest": "npx npm@\">= 10.2\" audit --production",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc -p . && eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git' | grep -v dist/)",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/es-object-atoms.git"
+	},
+	"keywords": [
+		"javascript",
+		"ecmascript",
+		"object",
+		"toobject",
+		"coercible"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/es-object-atoms/issues"
+	},
+	"homepage": "https://github.com/ljharb/es-object-atoms#readme",
+	"dependencies": {
+		"es-errors": "^1.3.0"
+	},
+	"devDependencies": {
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.3",
+		"@types/tape": "^5.8.1",
+		"auto-changelog": "^2.5.0",
+		"eclint": "^2.8.1",
+		"encoding": "^0.1.13",
+		"eslint": "^8.8.0",
+		"evalmd": "^0.0.19",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/es-object-atoms/test/index.js b/server/node_modules/es-object-atoms/test/index.js
new file mode 100644
index 0000000..430b705
--- /dev/null
+++ b/server/node_modules/es-object-atoms/test/index.js
@@ -0,0 +1,38 @@
+'use strict';
+
+var test = require('tape');
+
+var $Object = require('../');
+var isObject = require('../isObject');
+var ToObject = require('../ToObject');
+var RequireObjectCoercible = require('..//RequireObjectCoercible');
+
+test('errors', function (t) {
+	t.equal($Object, Object);
+	// @ts-expect-error
+	t['throws'](function () { ToObject(null); }, TypeError);
+	// @ts-expect-error
+	t['throws'](function () { ToObject(undefined); }, TypeError);
+	// @ts-expect-error
+	t['throws'](function () { RequireObjectCoercible(null); }, TypeError);
+	// @ts-expect-error
+	t['throws'](function () { RequireObjectCoercible(undefined); }, TypeError);
+
+	t.deepEqual(RequireObjectCoercible(true), true);
+	t.deepEqual(ToObject(true), Object(true));
+	t.deepEqual(ToObject(42), Object(42));
+	var f = function () {};
+	t.equal(ToObject(f), f);
+
+	t.equal(isObject(undefined), false);
+	t.equal(isObject(null), false);
+	t.equal(isObject({}), true);
+	t.equal(isObject([]), true);
+	t.equal(isObject(function () {}), true);
+
+	var obj = {};
+	t.equal(RequireObjectCoercible(obj), obj);
+	t.equal(ToObject(obj), obj);
+
+	t.end();
+});
diff --git a/server/node_modules/es-object-atoms/tsconfig.json b/server/node_modules/es-object-atoms/tsconfig.json
new file mode 100644
index 0000000..1f73cb7
--- /dev/null
+++ b/server/node_modules/es-object-atoms/tsconfig.json
@@ -0,0 +1,6 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "es5",
+	},
+}
diff --git a/server/node_modules/escape-html/LICENSE b/server/node_modules/escape-html/LICENSE
new file mode 100644
index 0000000..2e70de9
--- /dev/null
+++ b/server/node_modules/escape-html/LICENSE
@@ -0,0 +1,24 @@
+(The MIT License)
+
+Copyright (c) 2012-2013 TJ Holowaychuk
+Copyright (c) 2015 Andreas Lubbe
+Copyright (c) 2015 Tiancheng "Timothy" Gu
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/escape-html/Readme.md b/server/node_modules/escape-html/Readme.md
new file mode 100644
index 0000000..653d9ea
--- /dev/null
+++ b/server/node_modules/escape-html/Readme.md
@@ -0,0 +1,43 @@
+
+# escape-html
+
+  Escape string for use in HTML
+
+## Example
+
+```js
+var escape = require('escape-html');
+var html = escape('foo & bar');
+// -> foo & bar
+```
+
+## Benchmark
+
+```
+$ npm run-script bench
+
+> escape-html@1.0.3 bench nodejs-escape-html
+> node benchmark/index.js
+
+
+  http_parser@1.0
+  node@0.10.33
+  v8@3.14.5.9
+  ares@1.9.0-DEV
+  uv@0.10.29
+  zlib@1.2.3
+  modules@11
+  openssl@1.0.1j
+
+  1 test completed.
+  2 tests completed.
+  3 tests completed.
+
+  no special characters    x 19,435,271 ops/sec ±0.85% (187 runs sampled)
+  single special character x  6,132,421 ops/sec ±0.67% (194 runs sampled)
+  many special characters  x  3,175,826 ops/sec ±0.65% (193 runs sampled)
+```
+
+## License
+
+  MIT
\ No newline at end of file
diff --git a/server/node_modules/escape-html/index.js b/server/node_modules/escape-html/index.js
new file mode 100644
index 0000000..bf9e226
--- /dev/null
+++ b/server/node_modules/escape-html/index.js
@@ -0,0 +1,78 @@
+/*!
+ * escape-html
+ * Copyright(c) 2012-2013 TJ Holowaychuk
+ * Copyright(c) 2015 Andreas Lubbe
+ * Copyright(c) 2015 Tiancheng "Timothy" Gu
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var matchHtmlRegExp = /["'&<>]/;
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = escapeHtml;
+
+/**
+ * Escape special characters in the given string of html.
+ *
+ * @param  {string} string The string to escape for inserting into HTML
+ * @return {string}
+ * @public
+ */
+
+function escapeHtml(string) {
+  var str = '' + string;
+  var match = matchHtmlRegExp.exec(str);
+
+  if (!match) {
+    return str;
+  }
+
+  var escape;
+  var html = '';
+  var index = 0;
+  var lastIndex = 0;
+
+  for (index = match.index; index < str.length; index++) {
+    switch (str.charCodeAt(index)) {
+      case 34: // "
+        escape = '"';
+        break;
+      case 38: // &
+        escape = '&';
+        break;
+      case 39: // '
+        escape = ''';
+        break;
+      case 60: // <
+        escape = '<';
+        break;
+      case 62: // >
+        escape = '>';
+        break;
+      default:
+        continue;
+    }
+
+    if (lastIndex !== index) {
+      html += str.substring(lastIndex, index);
+    }
+
+    lastIndex = index + 1;
+    html += escape;
+  }
+
+  return lastIndex !== index
+    ? html + str.substring(lastIndex, index)
+    : html;
+}
diff --git a/server/node_modules/escape-html/package.json b/server/node_modules/escape-html/package.json
new file mode 100644
index 0000000..57ec7bd
--- /dev/null
+++ b/server/node_modules/escape-html/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "escape-html",
+  "description": "Escape string for use in HTML",
+  "version": "1.0.3",
+  "license": "MIT",
+  "keywords": [
+    "escape",
+    "html",
+    "utility"
+  ],
+  "repository": "component/escape-html",
+  "devDependencies": {
+    "benchmark": "1.0.0",
+    "beautify-benchmark": "0.2.4"
+  },
+  "files": [
+    "LICENSE",
+    "Readme.md",
+    "index.js"
+  ],
+  "scripts": {
+    "bench": "node benchmark/index.js"
+  }
+}
diff --git a/server/node_modules/etag/HISTORY.md b/server/node_modules/etag/HISTORY.md
new file mode 100644
index 0000000..222b293
--- /dev/null
+++ b/server/node_modules/etag/HISTORY.md
@@ -0,0 +1,83 @@
+1.8.1 / 2017-09-12
+==================
+
+  * perf: replace regular expression with substring
+
+1.8.0 / 2017-02-18
+==================
+
+  * Use SHA1 instead of MD5 for ETag hashing
+    - Improves performance for larger entities
+    - Works with FIPS 140-2 OpenSSL configuration
+
+1.7.0 / 2015-06-08
+==================
+
+  * Always include entity length in ETags for hash length extensions
+  * Generate non-Stats ETags using MD5 only (no longer CRC32)
+  * Improve stat performance by removing hashing
+  * Remove base64 padding in ETags to shorten
+  * Use MD5 instead of MD4 in weak ETags over 1KB
+
+1.6.0 / 2015-05-10
+==================
+
+  * Improve support for JXcore
+  * Remove requirement of `atime` in the stats object
+  * Support "fake" stats objects in environments without `fs`
+
+1.5.1 / 2014-11-19
+==================
+
+  * deps: crc@3.2.1
+    - Minor fixes
+
+1.5.0 / 2014-10-14
+==================
+
+  * Improve string performance
+  * Slightly improve speed for weak ETags over 1KB
+
+1.4.0 / 2014-09-21
+==================
+
+  * Support "fake" stats objects
+  * Support Node.js 0.6
+
+1.3.1 / 2014-09-14
+==================
+
+  * Use the (new and improved) `crc` for crc32
+
+1.3.0 / 2014-08-29
+==================
+
+  * Default strings to strong ETags
+  * Improve speed for weak ETags over 1KB
+
+1.2.1 / 2014-08-29
+==================
+
+  * Use the (much faster) `buffer-crc32` for crc32
+
+1.2.0 / 2014-08-24
+==================
+
+  * Add support for file stat objects
+
+1.1.0 / 2014-08-24
+==================
+
+  * Add fast-path for empty entity
+  * Add weak ETag generation
+  * Shrink size of generated ETags
+
+1.0.1 / 2014-08-24
+==================
+
+  * Fix behavior of string containing Unicode
+
+1.0.0 / 2014-05-18
+==================
+
+  * Initial release
diff --git a/server/node_modules/etag/LICENSE b/server/node_modules/etag/LICENSE
new file mode 100644
index 0000000..cab251c
--- /dev/null
+++ b/server/node_modules/etag/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2014-2016 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/etag/README.md b/server/node_modules/etag/README.md
new file mode 100644
index 0000000..09c2169
--- /dev/null
+++ b/server/node_modules/etag/README.md
@@ -0,0 +1,159 @@
+# etag
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Create simple HTTP ETags
+
+This module generates HTTP ETags (as defined in RFC 7232) for use in
+HTTP responses.
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install etag
+```
+
+## API
+
+
+
+```js
+var etag = require('etag')
+```
+
+### etag(entity, [options])
+
+Generate a strong ETag for the given entity. This should be the complete
+body of the entity. Strings, `Buffer`s, and `fs.Stats` are accepted. By
+default, a strong ETag is generated except for `fs.Stats`, which will
+generate a weak ETag (this can be overwritten by `options.weak`).
+
+
+
+```js
+res.setHeader('ETag', etag(body))
+```
+
+#### Options
+
+`etag` accepts these properties in the options object.
+
+##### weak
+
+Specifies if the generated ETag will include the weak validator mark (that
+is, the leading `W/`). The actual entity tag is the same. The default value
+is `false`, unless the `entity` is `fs.Stats`, in which case it is `true`.
+
+## Testing
+
+```sh
+$ npm test
+```
+
+## Benchmark
+
+```bash
+$ npm run-script bench
+
+> etag@1.8.1 bench nodejs-etag
+> node benchmark/index.js
+
+  http_parser@2.7.0
+  node@6.11.1
+  v8@5.1.281.103
+  uv@1.11.0
+  zlib@1.2.11
+  ares@1.10.1-DEV
+  icu@58.2
+  modules@48
+  openssl@1.0.2k
+
+> node benchmark/body0-100b.js
+
+  100B body
+
+  4 tests completed.
+
+  buffer - strong x 258,647 ops/sec ±1.07% (180 runs sampled)
+  buffer - weak   x 263,812 ops/sec ±0.61% (184 runs sampled)
+  string - strong x 259,955 ops/sec ±1.19% (185 runs sampled)
+  string - weak   x 264,356 ops/sec ±1.09% (184 runs sampled)
+
+> node benchmark/body1-1kb.js
+
+  1KB body
+
+  4 tests completed.
+
+  buffer - strong x 189,018 ops/sec ±1.12% (182 runs sampled)
+  buffer - weak   x 190,586 ops/sec ±0.81% (186 runs sampled)
+  string - strong x 144,272 ops/sec ±0.96% (188 runs sampled)
+  string - weak   x 145,380 ops/sec ±1.43% (187 runs sampled)
+
+> node benchmark/body2-5kb.js
+
+  5KB body
+
+  4 tests completed.
+
+  buffer - strong x 92,435 ops/sec ±0.42% (188 runs sampled)
+  buffer - weak   x 92,373 ops/sec ±0.58% (189 runs sampled)
+  string - strong x 48,850 ops/sec ±0.56% (186 runs sampled)
+  string - weak   x 49,380 ops/sec ±0.56% (190 runs sampled)
+
+> node benchmark/body3-10kb.js
+
+  10KB body
+
+  4 tests completed.
+
+  buffer - strong x 55,989 ops/sec ±0.93% (188 runs sampled)
+  buffer - weak   x 56,148 ops/sec ±0.55% (190 runs sampled)
+  string - strong x 27,345 ops/sec ±0.43% (188 runs sampled)
+  string - weak   x 27,496 ops/sec ±0.45% (190 runs sampled)
+
+> node benchmark/body4-100kb.js
+
+  100KB body
+
+  4 tests completed.
+
+  buffer - strong x 7,083 ops/sec ±0.22% (190 runs sampled)
+  buffer - weak   x 7,115 ops/sec ±0.26% (191 runs sampled)
+  string - strong x 3,068 ops/sec ±0.34% (190 runs sampled)
+  string - weak   x 3,096 ops/sec ±0.35% (190 runs sampled)
+
+> node benchmark/stats.js
+
+  stat
+
+  4 tests completed.
+
+  real - strong x 871,642 ops/sec ±0.34% (189 runs sampled)
+  real - weak   x 867,613 ops/sec ±0.39% (190 runs sampled)
+  fake - strong x 401,051 ops/sec ±0.40% (189 runs sampled)
+  fake - weak   x 400,100 ops/sec ±0.47% (188 runs sampled)
+```
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/etag.svg
+[npm-url]: https://npmjs.org/package/etag
+[node-version-image]: https://img.shields.io/node/v/etag.svg
+[node-version-url]: https://nodejs.org/en/download/
+[travis-image]: https://img.shields.io/travis/jshttp/etag/master.svg
+[travis-url]: https://travis-ci.org/jshttp/etag
+[coveralls-image]: https://img.shields.io/coveralls/jshttp/etag/master.svg
+[coveralls-url]: https://coveralls.io/r/jshttp/etag?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/etag.svg
+[downloads-url]: https://npmjs.org/package/etag
diff --git a/server/node_modules/etag/index.js b/server/node_modules/etag/index.js
new file mode 100644
index 0000000..2a585c9
--- /dev/null
+++ b/server/node_modules/etag/index.js
@@ -0,0 +1,131 @@
+/*!
+ * etag
+ * Copyright(c) 2014-2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = etag
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var crypto = require('crypto')
+var Stats = require('fs').Stats
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var toString = Object.prototype.toString
+
+/**
+ * Generate an entity tag.
+ *
+ * @param {Buffer|string} entity
+ * @return {string}
+ * @private
+ */
+
+function entitytag (entity) {
+  if (entity.length === 0) {
+    // fast-path empty
+    return '"0-2jmj7l5rSw0yVb/vlWAYkK/YBwk"'
+  }
+
+  // compute hash of entity
+  var hash = crypto
+    .createHash('sha1')
+    .update(entity, 'utf8')
+    .digest('base64')
+    .substring(0, 27)
+
+  // compute length of entity
+  var len = typeof entity === 'string'
+    ? Buffer.byteLength(entity, 'utf8')
+    : entity.length
+
+  return '"' + len.toString(16) + '-' + hash + '"'
+}
+
+/**
+ * Create a simple ETag.
+ *
+ * @param {string|Buffer|Stats} entity
+ * @param {object} [options]
+ * @param {boolean} [options.weak]
+ * @return {String}
+ * @public
+ */
+
+function etag (entity, options) {
+  if (entity == null) {
+    throw new TypeError('argument entity is required')
+  }
+
+  // support fs.Stats object
+  var isStats = isstats(entity)
+  var weak = options && typeof options.weak === 'boolean'
+    ? options.weak
+    : isStats
+
+  // validate argument
+  if (!isStats && typeof entity !== 'string' && !Buffer.isBuffer(entity)) {
+    throw new TypeError('argument entity must be string, Buffer, or fs.Stats')
+  }
+
+  // generate entity tag
+  var tag = isStats
+    ? stattag(entity)
+    : entitytag(entity)
+
+  return weak
+    ? 'W/' + tag
+    : tag
+}
+
+/**
+ * Determine if object is a Stats object.
+ *
+ * @param {object} obj
+ * @return {boolean}
+ * @api private
+ */
+
+function isstats (obj) {
+  // genuine fs.Stats
+  if (typeof Stats === 'function' && obj instanceof Stats) {
+    return true
+  }
+
+  // quack quack
+  return obj && typeof obj === 'object' &&
+    'ctime' in obj && toString.call(obj.ctime) === '[object Date]' &&
+    'mtime' in obj && toString.call(obj.mtime) === '[object Date]' &&
+    'ino' in obj && typeof obj.ino === 'number' &&
+    'size' in obj && typeof obj.size === 'number'
+}
+
+/**
+ * Generate a tag for a stat.
+ *
+ * @param {object} stat
+ * @return {string}
+ * @private
+ */
+
+function stattag (stat) {
+  var mtime = stat.mtime.getTime().toString(16)
+  var size = stat.size.toString(16)
+
+  return '"' + size + '-' + mtime + '"'
+}
diff --git a/server/node_modules/etag/package.json b/server/node_modules/etag/package.json
new file mode 100644
index 0000000..b06ab80
--- /dev/null
+++ b/server/node_modules/etag/package.json
@@ -0,0 +1,47 @@
+{
+  "name": "etag",
+  "description": "Create simple HTTP ETags",
+  "version": "1.8.1",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "David Björklund <david.bjorklund@gmail.com>"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "etag",
+    "http",
+    "res"
+  ],
+  "repository": "jshttp/etag",
+  "devDependencies": {
+    "beautify-benchmark": "0.2.4",
+    "benchmark": "2.1.4",
+    "eslint": "3.19.0",
+    "eslint-config-standard": "10.2.1",
+    "eslint-plugin-import": "2.7.0",
+    "eslint-plugin-markdown": "1.0.0-beta.6",
+    "eslint-plugin-node": "5.1.1",
+    "eslint-plugin-promise": "3.5.0",
+    "eslint-plugin-standard": "3.0.1",
+    "istanbul": "0.4.5",
+    "mocha": "1.21.5",
+    "safe-buffer": "5.1.1",
+    "seedrandom": "2.4.3"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  }
+}
diff --git a/server/node_modules/expand-template/.travis.yml b/server/node_modules/expand-template/.travis.yml
new file mode 100644
index 0000000..1335a77
--- /dev/null
+++ b/server/node_modules/expand-template/.travis.yml
@@ -0,0 +1,6 @@
+language: node_js
+
+node_js:
+  - 6
+  - 8
+  - 10
diff --git a/server/node_modules/expand-template/LICENSE b/server/node_modules/expand-template/LICENSE
new file mode 100644
index 0000000..814aef4
--- /dev/null
+++ b/server/node_modules/expand-template/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2018 Lars-Magnus Skog
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/expand-template/README.md b/server/node_modules/expand-template/README.md
new file mode 100644
index 0000000..b98aa48
--- /dev/null
+++ b/server/node_modules/expand-template/README.md
@@ -0,0 +1,43 @@
+# expand-template
+
+> Expand placeholders in a template string.
+
+[![npm](https://img.shields.io/npm/v/expand-template.svg)](https://www.npmjs.com/package/expand-template)
+![Node version](https://img.shields.io/node/v/expand-template.svg)
+[![Build Status](https://travis-ci.org/ralphtheninja/expand-template.svg?branch=master)](https://travis-ci.org/ralphtheninja/expand-template)
+[![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)
+
+## Install
+
+```
+$ npm i expand-template -S
+```
+
+## Usage
+
+Default functionality expands templates using `{}` as separators for string placeholders.
+
+```js
+var expand = require('expand-template')()
+var template = '{foo}/{foo}/{bar}/{bar}'
+console.log(expand(template, {
+  foo: 'BAR',
+  bar: 'FOO'
+}))
+// -> BAR/BAR/FOO/FOO
+```
+
+Custom separators:
+
+```js
+var expand = require('expand-template')({ sep: '[]' })
+var template = '[foo]/[foo]/[bar]/[bar]'
+console.log(expand(template, {
+  foo: 'BAR',
+  bar: 'FOO'
+}))
+// -> BAR/BAR/FOO/FOO
+```
+
+## License
+All code, unless stated otherwise, is dual-licensed under [`WTFPL`](http://www.wtfpl.net/txt/copying/) and [`MIT`](https://opensource.org/licenses/MIT).
diff --git a/server/node_modules/expand-template/index.js b/server/node_modules/expand-template/index.js
new file mode 100644
index 0000000..e182837
--- /dev/null
+++ b/server/node_modules/expand-template/index.js
@@ -0,0 +1,26 @@
+module.exports = function (opts) {
+  var sep = opts ? opts.sep : '{}'
+  var len = sep.length
+
+  var whitespace = '\\s*'
+  var left = escape(sep.substring(0, len / 2)) + whitespace
+  var right = whitespace + escape(sep.substring(len / 2, len))
+
+  return function (template, values) {
+    Object.keys(values).forEach(function (key) {
+      var value = String(values[key]).replace(/\$/g, '$$$$')
+      template = template.replace(regExp(key), value)
+    })
+    return template
+  }
+
+  function escape (s) {
+    return [].map.call(s, function (char) {
+      return '\\' + char
+    }).join('')
+  }
+
+  function regExp (key) {
+    return new RegExp(left + key + right, 'g')
+  }
+}
diff --git a/server/node_modules/expand-template/package.json b/server/node_modules/expand-template/package.json
new file mode 100644
index 0000000..9a09656
--- /dev/null
+++ b/server/node_modules/expand-template/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "expand-template",
+  "version": "2.0.3",
+  "description": "Expand placeholders in a template string",
+  "main": "index.js",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/ralphtheninja/expand-template.git"
+  },
+  "homepage": "https://github.com/ralphtheninja/expand-template",
+  "scripts": {
+    "test": "tape test.js && standard"
+  },
+  "keywords": [
+    "template",
+    "expand",
+    "replace"
+  ],
+  "author": "LM <ralphtheninja@riseup.net>",
+  "license": "(MIT OR WTFPL)",
+  "dependencies": {},
+  "devDependencies": {
+    "standard": "^12.0.0",
+    "tape": "^4.2.2"
+  },
+  "engines": {
+    "node": ">=6"
+  }
+}
diff --git a/server/node_modules/expand-template/test.js b/server/node_modules/expand-template/test.js
new file mode 100644
index 0000000..ba6ed87
--- /dev/null
+++ b/server/node_modules/expand-template/test.js
@@ -0,0 +1,67 @@
+var test = require('tape')
+var Expand = require('./')
+
+test('default expands {} placeholders', function (t) {
+  var expand = Expand()
+  t.equal(typeof expand, 'function', 'is a function')
+  t.equal(expand('{foo}/{bar}', {
+    foo: 'BAR', bar: 'FOO'
+  }), 'BAR/FOO')
+  t.equal(expand('{foo}{foo}{foo}', {
+    foo: 'FOO'
+  }), 'FOOFOOFOO', 'expands one placeholder many times')
+  t.end()
+})
+
+test('support for custom separators', function (t) {
+  var expand = Expand({ sep: '[]' })
+  t.equal(expand('[foo]/[bar]', {
+    foo: 'BAR', bar: 'FOO'
+  }), 'BAR/FOO')
+  t.equal(expand('[foo][foo][foo]', {
+    foo: 'FOO'
+  }), 'FOOFOOFOO', 'expands one placeholder many times')
+  t.end()
+})
+
+test('support for longer custom separators', function (t) {
+  var expand = Expand({ sep: '[[]]' })
+  t.equal(expand('[[foo]]/[[bar]]', {
+    foo: 'BAR', bar: 'FOO'
+  }), 'BAR/FOO')
+  t.equal(expand('[[foo]][[foo]][[foo]]', {
+    foo: 'FOO'
+  }), 'FOOFOOFOO', 'expands one placeholder many times')
+  t.end()
+})
+
+test('whitespace-insensitive', function (t) {
+  var expand = Expand({ sep: '[]' })
+  t.equal(expand('[ foo ]/[ bar ]', {
+    foo: 'BAR', bar: 'FOO'
+  }), 'BAR/FOO')
+  t.equal(expand('[ foo ][ foo  ][ foo]', {
+    foo: 'FOO'
+  }), 'FOOFOOFOO', 'expands one placeholder many times')
+  t.end()
+})
+
+test('dollar escape', function (t) {
+  var expand = Expand()
+  t.equal(expand('before {foo} after', {
+    foo: '$'
+  }), 'before $ after')
+  t.equal(expand('before {foo} after', {
+    foo: '$&'
+  }), 'before $& after')
+  t.equal(expand('before {foo} after', {
+    foo: '$`'
+  }), 'before $` after')
+  t.equal(expand('before {foo} after', {
+    foo: '$\''
+  }), 'before $\' after')
+  t.equal(expand('before {foo} after', {
+    foo: '$0'
+  }), 'before $0 after')
+  t.end()
+})
diff --git a/server/node_modules/express-session/LICENSE b/server/node_modules/express-session/LICENSE
new file mode 100644
index 0000000..9b59ff8
--- /dev/null
+++ b/server/node_modules/express-session/LICENSE
@@ -0,0 +1,24 @@
+(The MIT License)
+
+Copyright (c) 2010 Sencha Inc.
+Copyright (c) 2011 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2014-2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/express-session/README.md b/server/node_modules/express-session/README.md
new file mode 100644
index 0000000..292b202
--- /dev/null
+++ b/server/node_modules/express-session/README.md
@@ -0,0 +1,1061 @@
+# express-session
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][node-url]
+[![Build Status][ci-image]][ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install express-session
+```
+
+## API
+
+```js
+var session = require('express-session')
+```
+
+### session(options)
+
+Create a session middleware with the given `options`.
+
+**Note** Session data is _not_ saved in the cookie itself, just the session ID.
+Session data is stored server-side.
+
+**Note** Since version 1.5.0, the [`cookie-parser` middleware](https://www.npmjs.com/package/cookie-parser)
+no longer needs to be used for this module to work. This module now directly reads
+and writes cookies on `req`/`res`. Using `cookie-parser` may result in issues
+if the `secret` is not the same between this module and `cookie-parser`.
+
+**Warning** The default server-side session storage, `MemoryStore`, is _purposely_
+not designed for a production environment. It will leak memory under most
+conditions, does not scale past a single process, and is meant for debugging and
+developing.
+
+For a list of stores, see [compatible session stores](#compatible-session-stores).
+
+#### Options
+
+`express-session` accepts these properties in the options object.
+
+##### cookie
+
+Settings object for the session ID cookie. The default value is
+`{ path: '/', httpOnly: true, secure: false, maxAge: null }`.
+
+In addition to providing a static object, you can also pass a callback function to dynamically generate the cookie options for each request. The callback receives the `req` object as its argument and should return an object containing the cookie settings.
+
+```js
+var app = express()
+app.use(session({
+  secret: 'keyboard cat',
+  resave: false,
+  saveUninitialized: true,
+  cookie: function(req) {
+    var match = req.url.match(/^\/([^/]+)/);
+    return {
+      path: match ? '/' + match[1] : '/',
+      httpOnly: true,
+      secure: req.secure || false,
+      maxAge: 60000
+    }
+  }
+}))
+```
+
+The following are options that can be set in this object.
+
+##### cookie.domain
+
+Specifies the value for the `Domain` `Set-Cookie` attribute. By default, no domain
+is set, and most clients will consider the cookie to apply to only the current
+domain.
+
+##### cookie.expires
+
+Specifies the `Date` object to be the value for the `Expires` `Set-Cookie` attribute.
+By default, no expiration is set, and most clients will consider this a
+"non-persistent cookie" and will delete it on a condition like exiting a web browser
+application.
+
+**Note** If both `expires` and `maxAge` are set in the options, then the last one
+defined in the object is what is used.
+
+**Note** The `expires` option should not be set directly; instead only use the `maxAge`
+option.
+
+##### cookie.httpOnly
+
+Specifies the `boolean` value for the `HttpOnly` `Set-Cookie` attribute. When truthy,
+the `HttpOnly` attribute is set, otherwise it is not. By default, the `HttpOnly`
+attribute is set.
+
+**Note** be careful when setting this to `true`, as compliant clients will not allow
+client-side JavaScript to see the cookie in `document.cookie`.
+
+##### cookie.maxAge
+
+Specifies the `number` (in milliseconds) to use when calculating the `Expires`
+`Set-Cookie` attribute. This is done by taking the current server time and adding
+`maxAge` milliseconds to the value to calculate an `Expires` datetime. By default,
+no maximum age is set.
+
+**Note** If both `expires` and `maxAge` are set in the options, then the last one
+defined in the object is what is used.
+
+##### cookie.partitioned
+
+Specifies the `boolean` value for the [`Partitioned` `Set-Cookie`](rfc-cutler-httpbis-partitioned-cookies)
+attribute. When truthy, the `Partitioned` attribute is set, otherwise it is not.
+By default, the `Partitioned` attribute is not set.
+
+**Note** This is an attribute that has not yet been fully standardized, and may
+change in the future. This also means many clients may ignore this attribute until
+they understand it.
+
+More information about can be found in [the proposal](https://github.com/privacycg/CHIPS).
+
+##### cookie.path
+
+Specifies the value for the `Path` `Set-Cookie`. By default, this is set to `'/'`, which
+is the root path of the domain.
+
+##### cookie.priority
+
+Specifies the `string` to be the value for the [`Priority` `Set-Cookie` attribute][rfc-west-cookie-priority-00-4.1].
+
+  - `'low'` will set the `Priority` attribute to `Low`.
+  - `'medium'` will set the `Priority` attribute to `Medium`, the default priority when not set.
+  - `'high'` will set the `Priority` attribute to `High`.
+
+More information about the different priority levels can be found in
+[the specification][rfc-west-cookie-priority-00-4.1].
+
+**Note** This is an attribute that has not yet been fully standardized, and may change in the future.
+This also means many clients may ignore this attribute until they understand it.
+
+##### cookie.sameSite
+
+Specifies the `boolean` or `string` to be the value for the `SameSite` `Set-Cookie` attribute.
+By default, this is `false`.
+
+  - `true` will set the `SameSite` attribute to `Strict` for strict same site enforcement.
+  - `false` will not set the `SameSite` attribute.
+  - `'lax'` will set the `SameSite` attribute to `Lax` for lax same site enforcement.
+  - `'none'` will set the `SameSite` attribute to `None` for an explicit cross-site cookie.
+  - `'strict'` will set the `SameSite` attribute to `Strict` for strict same site enforcement.
+  - `'auto'` will set the `SameSite` attribute to `None` for secure connections and `Lax` for non-secure connections.
+
+More information about the different enforcement levels can be found in
+[the specification][rfc-6265bis-03-4.1.2.7].
+
+**Note** This is an attribute that has not yet been fully standardized, and may change in
+the future. This also means many clients may ignore this attribute until they understand it.
+
+**Note** There is a [draft spec](https://tools.ietf.org/html/draft-west-cookie-incrementalism-01)
+that requires that the `Secure` attribute be set to `true` when the `SameSite` attribute has been
+set to `'none'`. Some web browsers or other clients may be adopting this specification.
+
+The `cookie.sameSite` option can also be set to the special value `'auto'` to have
+this setting automatically match the determined security of the connection. When the connection
+is secure (HTTPS), the `SameSite` attribute will be set to `None` to enable cross-site usage.
+When the connection is not secure (HTTP), the `SameSite` attribute will be set to `Lax` for
+better security while maintaining functionality. This is useful when the Express `"trust proxy"`
+setting is properly setup to simplify development vs production configuration, particularly
+for SAML authentication scenarios.
+
+##### cookie.secure
+
+Specifies the `boolean` value for the `Secure` `Set-Cookie` attribute. When truthy,
+the `Secure` attribute is set, otherwise it is not. By default, the `Secure`
+attribute is not set.
+
+**Note** be careful when setting this to `true`, as compliant clients will not send
+the cookie back to the server in the future if the browser does not have an HTTPS
+connection.
+
+Please note that `secure: true` is a **recommended** option. However, it requires
+an https-enabled website, i.e., HTTPS is necessary for secure cookies. If `secure`
+is set, and you access your site over HTTP, the cookie will not be set. If you
+have your node.js behind a proxy and are using `secure: true`, you need to set
+"trust proxy" in express:
+
+```js
+var app = express()
+app.set('trust proxy', 1) // trust first proxy
+app.use(session({
+  secret: 'keyboard cat',
+  resave: false,
+  saveUninitialized: true,
+  cookie: { secure: true }
+}))
+```
+
+For using secure cookies in production, but allowing for testing in development,
+the following is an example of enabling this setup based on `NODE_ENV` in express:
+
+```js
+var app = express()
+var sess = {
+  secret: 'keyboard cat',
+  cookie: {}
+}
+
+if (app.get('env') === 'production') {
+  app.set('trust proxy', 1) // trust first proxy
+  sess.cookie.secure = true // serve secure cookies
+}
+
+app.use(session(sess))
+```
+
+The `cookie.secure` option can also be set to the special value `'auto'` to have
+this setting automatically match the determined security of the connection. Be
+careful when using this setting if the site is available both as HTTP and HTTPS,
+as once the cookie is set on HTTPS, it will no longer be visible over HTTP. This
+is useful when the Express `"trust proxy"` setting is properly setup to simplify
+development vs production configuration.
+
+##### genid
+
+Function to call to generate a new session ID. Provide a function that returns
+a string that will be used as a session ID. The function is given `req` as the
+first argument if you want to use some value attached to `req` when generating
+the ID.
+
+The default value is a function which uses the `uid-safe` library to generate IDs.
+
+**NOTE** be careful to generate unique IDs so your sessions do not conflict.
+
+```js
+app.use(session({
+  genid: function(req) {
+    return genuuid() // use UUIDs for session IDs
+  },
+  secret: 'keyboard cat'
+}))
+```
+
+##### name
+
+The name of the session ID cookie to set in the response (and read from in the
+request).
+
+The default value is `'connect.sid'`.
+
+**Note** if you have multiple apps running on the same hostname (this is just
+the name, i.e. `localhost` or `127.0.0.1`; different schemes and ports do not
+name a different hostname), then you need to separate the session cookies from
+each other. The simplest method is to simply set different `name`s per app.
+
+##### proxy
+
+Trust the reverse proxy when setting secure cookies (via the "X-Forwarded-Proto"
+header).
+
+The default value is `undefined`.
+
+  - `true` The "X-Forwarded-Proto" header will be used.
+  - `false` All headers are ignored and the connection is considered secure only
+    if there is a direct TLS/SSL connection.
+  - `undefined` Uses the "trust proxy" setting from express
+
+##### resave
+
+Forces the session to be saved back to the session store, even if the session
+was never modified during the request. Depending on your store this may be
+necessary, but it can also create race conditions where a client makes two
+parallel requests to your server and changes made to the session in one
+request may get overwritten when the other request ends, even if it made no
+changes (this behavior also depends on what store you're using).
+
+The default value is `true`, but using the default has been deprecated,
+as the default will change in the future. Please research into this setting
+and choose what is appropriate to your use-case. Typically, you'll want
+`false`.
+
+How do I know if this is necessary for my store? The best way to know is to
+check with your store if it implements the `touch` method. If it does, then
+you can safely set `resave: false`. If it does not implement the `touch`
+method and your store sets an expiration date on stored sessions, then you
+likely need `resave: true`.
+
+##### rolling
+
+Force the session identifier cookie to be set on every response. The expiration
+is reset to the original [`maxAge`](#cookiemaxage), resetting the expiration
+countdown.
+
+The default value is `false`.
+
+With this enabled, the session identifier cookie will expire in
+[`maxAge`](#cookiemaxage) since the last response was sent instead of in
+[`maxAge`](#cookiemaxage) since the session was last modified by the server.
+
+This is typically used in conjunction with short, non-session-length
+[`maxAge`](#cookiemaxage) values to provide a quick timeout of the session data
+with reduced potential of it occurring during on going server interactions.
+
+**Note** When this option is set to `true` but the `saveUninitialized` option is
+set to `false`, the cookie will not be set on a response with an uninitialized
+session. This option only modifies the behavior when an existing session was
+loaded for the request.
+
+##### saveUninitialized
+
+Forces a session that is "uninitialized" to be saved to the store. A session is
+uninitialized when it is new but not modified. Choosing `false` is useful for
+implementing login sessions, reducing server storage usage, or complying with
+laws that require permission before setting a cookie. Choosing `false` will also
+help with race conditions where a client makes multiple parallel requests
+without a session.
+
+The default value is `true`, but using the default has been deprecated, as the
+default will change in the future. Please research into this setting and
+choose what is appropriate to your use-case.
+
+**Note** if you are using Session in conjunction with PassportJS, Passport
+will add an empty Passport object to the session for use after a user is
+authenticated, which will be treated as a modification to the session, causing
+it to be saved. *This has been fixed in PassportJS 0.3.0*
+
+##### secret
+
+**Required option**
+
+This is the secret used to sign the session ID cookie. The secret can be any type
+of value that is supported by Node.js `crypto.createHmac` (like a string or a
+`Buffer`). This can be either a single secret, or an array of multiple secrets. If
+an array of secrets is provided, only the first element will be used to sign the
+session ID cookie, while all the elements will be considered when verifying the
+signature in requests. The secret itself should be not easily parsed by a human and
+would best be a random set of characters. A best practice may include:
+
+  - The use of environment variables to store the secret, ensuring the secret itself
+    does not exist in your repository.
+  - Periodic updates of the secret, while ensuring the previous secret is in the
+    array.
+
+Using a secret that cannot be guessed will reduce the ability to hijack a session to
+only guessing the session ID (as determined by the `genid` option).
+
+Changing the secret value will invalidate all existing sessions. In order to rotate
+the secret without invalidating sessions, provide an array of secrets, with the new
+secret as first element of the array, and including previous secrets as the later
+elements.
+
+**Note** HMAC-256 is used to sign the session ID. For this reason, the secret should
+contain at least 32 bytes of entropy.
+
+##### store
+
+The session store instance, defaults to a new `MemoryStore` instance.
+
+##### unset
+
+Control the result of unsetting `req.session` (through `delete`, setting to `null`,
+etc.).
+
+The default value is `'keep'`.
+
+  - `'destroy'` The session will be destroyed (deleted) when the response ends.
+  - `'keep'` The session in the store will be kept, but modifications made during
+    the request are ignored and not saved.
+
+### req.session
+
+To store or access session data, simply use the request property `req.session`,
+which is (generally) serialized as JSON by the store, so nested objects
+are typically fine. For example below is a user-specific view counter:
+
+```js
+// Use the session middleware
+app.use(session({ secret: 'keyboard cat', cookie: { maxAge: 60000 }}))
+
+// Access the session as req.session
+app.get('/', function(req, res, next) {
+  if (req.session.views) {
+    req.session.views++
+    res.setHeader('Content-Type', 'text/html')
+    res.write('<p>views: ' + req.session.views + '</p>')
+    res.write('<p>expires in: ' + (req.session.cookie.maxAge / 1000) + 's</p>')
+    res.end()
+  } else {
+    req.session.views = 1
+    res.end('welcome to the session demo. refresh!')
+  }
+})
+```
+
+#### Session.regenerate(callback)
+
+To regenerate the session simply invoke the method. Once complete,
+a new SID and `Session` instance will be initialized at `req.session`
+and the `callback` will be invoked.
+
+```js
+req.session.regenerate(function(err) {
+  // will have a new session here
+})
+```
+
+#### Session.destroy(callback)
+
+Destroys the session and will unset the `req.session` property.
+Once complete, the `callback` will be invoked.
+
+```js
+req.session.destroy(function(err) {
+  // cannot access session here
+})
+```
+
+#### Session.reload(callback)
+
+Reloads the session data from the store and re-populates the
+`req.session` object. Once complete, the `callback` will be invoked.
+
+```js
+req.session.reload(function(err) {
+  // session updated
+})
+```
+
+#### Session.save(callback)
+
+Save the session back to the store, replacing the contents on the store with the
+contents in memory (though a store may do something else--consult the store's
+documentation for exact behavior).
+
+This method is automatically called at the end of the HTTP response if the
+session data has been altered (though this behavior can be altered with various
+options in the middleware constructor). Because of this, typically this method
+does not need to be called.
+
+There are some cases where it is useful to call this method, for example,
+redirects, long-lived requests or in WebSockets.
+
+```js
+req.session.save(function(err) {
+  // session saved
+})
+```
+
+#### Session.touch()
+
+Updates the `.maxAge` property. Typically this is
+not necessary to call, as the session middleware does this for you.
+
+### req.session.id
+
+Each session has a unique ID associated with it. This property is an
+alias of [`req.sessionID`](#reqsessionid-1) and cannot be modified.
+It has been added to make the session ID accessible from the `session`
+object.
+
+### req.session.cookie
+
+Each session has a unique cookie object accompany it. This allows
+you to alter the session cookie per visitor. For example we can
+set `req.session.cookie.expires` to `false` to enable the cookie
+to remain for only the duration of the user-agent.
+
+#### Cookie.maxAge
+
+Alternatively `req.session.cookie.maxAge` will return the time
+remaining in milliseconds, which we may also re-assign a new value
+to adjust the `.expires` property appropriately. The following
+are essentially equivalent
+
+```js
+var hour = 3600000
+req.session.cookie.expires = new Date(Date.now() + hour)
+req.session.cookie.maxAge = hour
+```
+
+For example when `maxAge` is set to `60000` (one minute), and 30 seconds
+has elapsed it will return `30000` until the current request has completed,
+at which time `req.session.touch()` is called to reset
+`req.session.cookie.maxAge` to its original value.
+
+```js
+req.session.cookie.maxAge // => 30000
+```
+
+#### Cookie.originalMaxAge
+
+The `req.session.cookie.originalMaxAge` property returns the original
+`maxAge` (time-to-live), in milliseconds, of the session cookie.
+
+### req.sessionID
+
+To get the ID of the loaded session, access the request property
+`req.sessionID`. This is simply a read-only value set when a session
+is loaded/created.
+
+## Session Store Implementation
+
+Every session store _must_ be an `EventEmitter` and implement specific
+methods. The following methods are the list of **required**, **recommended**,
+and **optional**.
+
+  * Required methods are ones that this module will always call on the store.
+  * Recommended methods are ones that this module will call on the store if
+    available.
+  * Optional methods are ones this module does not call at all, but helps
+    present uniform stores to users.
+
+For an example implementation view the [connect-redis](http://github.com/visionmedia/connect-redis) repo.
+
+### store.all(callback)
+
+**Optional**
+
+This optional method is used to get all sessions in the store as an array. The
+`callback` should be called as `callback(error, sessions)`.
+
+### store.destroy(sid, callback)
+
+**Required**
+
+This required method is used to destroy/delete a session from the store given
+a session ID (`sid`). The `callback` should be called as `callback(error)` once
+the session is destroyed.
+
+### store.clear(callback)
+
+**Optional**
+
+This optional method is used to delete all sessions from the store. The
+`callback` should be called as `callback(error)` once the store is cleared.
+
+### store.length(callback)
+
+**Optional**
+
+This optional method is used to get the count of all sessions in the store.
+The `callback` should be called as `callback(error, len)`.
+
+### store.get(sid, callback)
+
+**Required**
+
+This required method is used to get a session from the store given a session
+ID (`sid`). The `callback` should be called as `callback(error, session)`.
+
+The `session` argument should be a session if found, otherwise `null` or
+`undefined` if the session was not found (and there was no error). A special
+case is made when `error.code === 'ENOENT'` to act like `callback(null, null)`.
+
+### store.set(sid, session, callback)
+
+**Required**
+
+This required method is used to upsert a session into the store given a
+session ID (`sid`) and session (`session`) object. The callback should be
+called as `callback(error)` once the session has been set in the store.
+
+### store.touch(sid, session, callback)
+
+**Recommended**
+
+This recommended method is used to "touch" a given session given a
+session ID (`sid`) and session (`session`) object. The `callback` should be
+called as `callback(error)` once the session has been touched.
+
+This is primarily used when the store will automatically delete idle sessions
+and this method is used to signal to the store the given session is active,
+potentially resetting the idle timer.
+
+## Compatible Session Stores
+
+The following modules implement a session store that is compatible with this
+module. Please make a PR to add additional modules :)
+
+[![★][aerospike-session-store-image] aerospike-session-store][aerospike-session-store-url] A session store using [Aerospike](http://www.aerospike.com/).
+
+[aerospike-session-store-url]: https://www.npmjs.com/package/aerospike-session-store
+[aerospike-session-store-image]: https://badgen.net/github/stars/aerospike/aerospike-session-store-expressjs?label=%E2%98%85
+
+[![★][better-sqlite3-session-store-image] better-sqlite3-session-store][better-sqlite3-session-store-url] A session store based on [better-sqlite3](https://github.com/JoshuaWise/better-sqlite3).
+
+[better-sqlite3-session-store-url]: https://www.npmjs.com/package/better-sqlite3-session-store
+[better-sqlite3-session-store-image]: https://badgen.net/github/stars/timdaub/better-sqlite3-session-store?label=%E2%98%85
+
+[![★][cassandra-store-image] cassandra-store][cassandra-store-url] An Apache Cassandra-based session store.
+
+[cassandra-store-url]: https://www.npmjs.com/package/cassandra-store
+[cassandra-store-image]: https://badgen.net/github/stars/webcc/cassandra-store?label=%E2%98%85
+
+[![★][cluster-store-image] cluster-store][cluster-store-url] A wrapper for using in-process / embedded
+stores - such as SQLite (via knex), leveldb, files, or memory - with node cluster (desirable for Raspberry Pi 2
+and other multi-core embedded devices).
+
+[cluster-store-url]: https://www.npmjs.com/package/cluster-store
+[cluster-store-image]: https://badgen.net/github/stars/coolaj86/cluster-store?label=%E2%98%85
+
+[![★][connect-arango-image] connect-arango][connect-arango-url] An ArangoDB-based session store.
+
+[connect-arango-url]: https://www.npmjs.com/package/connect-arango
+[connect-arango-image]: https://badgen.net/github/stars/AlexanderArvidsson/connect-arango?label=%E2%98%85
+
+[![★][connect-azuretables-image] connect-azuretables][connect-azuretables-url] An [Azure Table Storage](https://azure.microsoft.com/en-gb/services/storage/tables/)-based session store.
+
+[connect-azuretables-url]: https://www.npmjs.com/package/connect-azuretables
+[connect-azuretables-image]: https://badgen.net/github/stars/mike-goodwin/connect-azuretables?label=%E2%98%85
+
+[![★][connect-cloudant-store-image] connect-cloudant-store][connect-cloudant-store-url] An [IBM Cloudant](https://cloudant.com/)-based session store.
+
+[connect-cloudant-store-url]: https://www.npmjs.com/package/connect-cloudant-store
+[connect-cloudant-store-image]: https://badgen.net/github/stars/adriantanasa/connect-cloudant-store?label=%E2%98%85
+
+[![★][connect-cosmosdb-image] connect-cosmosdb][connect-cosmosdb-url] An Azure [Cosmos DB](https://azure.microsoft.com/en-us/products/cosmos-db/)-based session store.
+
+[connect-cosmosdb-url]: https://www.npmjs.com/package/connect-cosmosdb
+[connect-cosmosdb-image]: https://badgen.net/github/stars/thekillingspree/connect-cosmosdb?label=%E2%98%85
+
+[![★][connect-couchbase-image] connect-couchbase][connect-couchbase-url] A [couchbase](http://www.couchbase.com/)-based session store.
+
+[connect-couchbase-url]: https://www.npmjs.com/package/connect-couchbase
+[connect-couchbase-image]: https://badgen.net/github/stars/christophermina/connect-couchbase?label=%E2%98%85
+
+[![★][connect-datacache-image] connect-datacache][connect-datacache-url] An [IBM Bluemix Data Cache](http://www.ibm.com/cloud-computing/bluemix/)-based session store.
+
+[connect-datacache-url]: https://www.npmjs.com/package/connect-datacache
+[connect-datacache-image]: https://badgen.net/github/stars/adriantanasa/connect-datacache?label=%E2%98%85
+
+[![★][@google-cloud/connect-datastore-image] @google-cloud/connect-datastore][@google-cloud/connect-datastore-url] A [Google Cloud Datastore](https://cloud.google.com/datastore/docs/concepts/overview)-based session store.
+
+[@google-cloud/connect-datastore-url]: https://www.npmjs.com/package/@google-cloud/connect-datastore
+[@google-cloud/connect-datastore-image]: https://badgen.net/github/stars/GoogleCloudPlatform/cloud-datastore-session-node?label=%E2%98%85
+
+[![★][connect-db2-image] connect-db2][connect-db2-url] An IBM DB2-based session store built using [ibm_db](https://www.npmjs.com/package/ibm_db) module.
+
+[connect-db2-url]: https://www.npmjs.com/package/connect-db2
+[connect-db2-image]: https://badgen.net/github/stars/wallali/connect-db2?label=%E2%98%85
+
+[![★][connect-dynamodb-image] connect-dynamodb][connect-dynamodb-url] A DynamoDB-based session store.
+
+[connect-dynamodb-url]: https://www.npmjs.com/package/connect-dynamodb
+[connect-dynamodb-image]: https://badgen.net/github/stars/ca98am79/connect-dynamodb?label=%E2%98%85
+
+[![★][@google-cloud/connect-firestore-image] @google-cloud/connect-firestore][@google-cloud/connect-firestore-url] A [Google Cloud Firestore](https://cloud.google.com/firestore/docs/overview)-based session store.
+
+[@google-cloud/connect-firestore-url]: https://www.npmjs.com/package/@google-cloud/connect-firestore
+[@google-cloud/connect-firestore-image]: https://badgen.net/github/stars/googleapis/nodejs-firestore-session?label=%E2%98%85
+
+[![★][connect-hazelcast-image] connect-hazelcast][connect-hazelcast-url] Hazelcast session store for Connect and Express.
+
+[connect-hazelcast-url]: https://www.npmjs.com/package/connect-hazelcast
+[connect-hazelcast-image]: https://badgen.net/github/stars/huseyinbabal/connect-hazelcast?label=%E2%98%85
+
+[![★][connect-loki-image] connect-loki][connect-loki-url] A Loki.js-based session store.
+
+[connect-loki-url]: https://www.npmjs.com/package/connect-loki
+[connect-loki-image]: https://badgen.net/github/stars/Requarks/connect-loki?label=%E2%98%85
+
+[![★][connect-lowdb-image] connect-lowdb][connect-lowdb-url] A lowdb-based session store.
+
+[connect-lowdb-url]: https://www.npmjs.com/package/connect-lowdb
+[connect-lowdb-image]: https://badgen.net/github/stars/travishorn/connect-lowdb?label=%E2%98%85
+
+[![★][connect-memcached-image] connect-memcached][connect-memcached-url] A memcached-based session store.
+
+[connect-memcached-url]: https://www.npmjs.com/package/connect-memcached
+[connect-memcached-image]: https://badgen.net/github/stars/balor/connect-memcached?label=%E2%98%85
+
+[![★][connect-memjs-image] connect-memjs][connect-memjs-url] A memcached-based session store using
+[memjs](https://www.npmjs.com/package/memjs) as the memcached client.
+
+[connect-memjs-url]: https://www.npmjs.com/package/connect-memjs
+[connect-memjs-image]: https://badgen.net/github/stars/liamdon/connect-memjs?label=%E2%98%85
+
+[![★][connect-ml-image] connect-ml][connect-ml-url] A MarkLogic Server-based session store.
+
+[connect-ml-url]: https://www.npmjs.com/package/connect-ml
+[connect-ml-image]: https://badgen.net/github/stars/bluetorch/connect-ml?label=%E2%98%85
+
+[![★][connect-monetdb-image] connect-monetdb][connect-monetdb-url] A MonetDB-based session store.
+
+[connect-monetdb-url]: https://www.npmjs.com/package/connect-monetdb
+[connect-monetdb-image]: https://badgen.net/github/stars/MonetDB/npm-connect-monetdb?label=%E2%98%85
+
+[![★][connect-mongo-image] connect-mongo][connect-mongo-url] A MongoDB-based session store.
+
+[connect-mongo-url]: https://www.npmjs.com/package/connect-mongo
+[connect-mongo-image]: https://badgen.net/github/stars/kcbanner/connect-mongo?label=%E2%98%85
+
+[![★][connect-mongodb-session-image] connect-mongodb-session][connect-mongodb-session-url] Lightweight MongoDB-based session store built and maintained by MongoDB.
+
+[connect-mongodb-session-url]: https://www.npmjs.com/package/connect-mongodb-session
+[connect-mongodb-session-image]: https://badgen.net/github/stars/mongodb-js/connect-mongodb-session?label=%E2%98%85
+
+[![★][connect-mssql-v2-image] connect-mssql-v2][connect-mssql-v2-url] A Microsoft SQL Server-based session store based on [connect-mssql](https://www.npmjs.com/package/connect-mssql).
+
+[connect-mssql-v2-url]: https://www.npmjs.com/package/connect-mssql-v2
+[connect-mssql-v2-image]: https://badgen.net/github/stars/jluboff/connect-mssql-v2?label=%E2%98%85
+
+[![★][connect-neo4j-image] connect-neo4j][connect-neo4j-url] A [Neo4j](https://neo4j.com)-based session store.
+
+[connect-neo4j-url]: https://www.npmjs.com/package/connect-neo4j
+[connect-neo4j-image]: https://badgen.net/github/stars/MaxAndersson/connect-neo4j?label=%E2%98%85
+
+[![★][connect-ottoman-image] connect-ottoman][connect-ottoman-url] A [couchbase ottoman](http://www.couchbase.com/)-based session store.
+
+[connect-ottoman-url]: https://www.npmjs.com/package/connect-ottoman
+[connect-ottoman-image]: https://badgen.net/github/stars/noiissyboy/connect-ottoman?label=%E2%98%85
+
+[![★][connect-pg-simple-image] connect-pg-simple][connect-pg-simple-url] A PostgreSQL-based session store.
+
+[connect-pg-simple-url]: https://www.npmjs.com/package/connect-pg-simple
+[connect-pg-simple-image]: https://badgen.net/github/stars/voxpelli/node-connect-pg-simple?label=%E2%98%85
+
+[![★][connect-redis-image] connect-redis][connect-redis-url] A Redis-based session store.
+
+[connect-redis-url]: https://www.npmjs.com/package/connect-redis
+[connect-redis-image]: https://badgen.net/github/stars/tj/connect-redis?label=%E2%98%85
+
+[![★][connect-session-firebase-image] connect-session-firebase][connect-session-firebase-url] A session store based on the [Firebase Realtime Database](https://firebase.google.com/docs/database/)
+
+[connect-session-firebase-url]: https://www.npmjs.com/package/connect-session-firebase
+[connect-session-firebase-image]: https://badgen.net/github/stars/benweier/connect-session-firebase?label=%E2%98%85
+
+[![★][connect-session-knex-image] connect-session-knex][connect-session-knex-url] A session store using
+[Knex.js](http://knexjs.org/), which is a SQL query builder for PostgreSQL, MySQL, MariaDB, SQLite3, and Oracle.
+
+[connect-session-knex-url]: https://www.npmjs.com/package/connect-session-knex
+[connect-session-knex-image]: https://badgen.net/github/stars/llambda/connect-session-knex?label=%E2%98%85
+
+[![★][connect-session-sequelize-image] connect-session-sequelize][connect-session-sequelize-url] A session store using
+[Sequelize.js](http://sequelizejs.com/), which is a Node.js / io.js ORM for PostgreSQL, MySQL, SQLite and MSSQL.
+
+[connect-session-sequelize-url]: https://www.npmjs.com/package/connect-session-sequelize
+[connect-session-sequelize-image]: https://badgen.net/github/stars/mweibel/connect-session-sequelize?label=%E2%98%85
+
+[![★][connect-sqlite3-image] connect-sqlite3][connect-sqlite3-url] A [SQLite3](https://github.com/mapbox/node-sqlite3) session store modeled after the TJ's `connect-redis` store.
+
+[connect-sqlite3-url]: https://www.npmjs.com/package/connect-sqlite3
+[connect-sqlite3-image]: https://badgen.net/github/stars/rawberg/connect-sqlite3?label=%E2%98%85
+
+[![★][connect-typeorm-image] connect-typeorm][connect-typeorm-url] A [TypeORM](https://github.com/typeorm/typeorm)-based session store.
+
+[connect-typeorm-url]: https://www.npmjs.com/package/connect-typeorm
+[connect-typeorm-image]: https://badgen.net/github/stars/makepost/connect-typeorm?label=%E2%98%85
+
+[![★][couchdb-expression-image] couchdb-expression][couchdb-expression-url] A [CouchDB](https://couchdb.apache.org/)-based session store.
+
+[couchdb-expression-url]: https://www.npmjs.com/package/couchdb-expression
+[couchdb-expression-image]: https://badgen.net/github/stars/tkshnwesper/couchdb-expression?label=%E2%98%85
+
+[![★][dynamodb-store-image] dynamodb-store][dynamodb-store-url] A DynamoDB-based session store.
+
+[dynamodb-store-url]: https://www.npmjs.com/package/dynamodb-store
+[dynamodb-store-image]: https://badgen.net/github/stars/rafaelrpinto/dynamodb-store?label=%E2%98%85
+
+[![★][dynamodb-store-v3-image] dynamodb-store-v3][dynamodb-store-v3-url] Implementation of a session store using DynamoDB backed by the [AWS SDK for JavaScript v3](https://github.com/aws/aws-sdk-js-v3).
+
+[dynamodb-store-v3-url]: https://www.npmjs.com/package/dynamodb-store-v3
+[dynamodb-store-v3-image]: https://badgen.net/github/stars/FryDay/dynamodb-store-v3?label=%E2%98%85
+
+[![★][express-etcd-image] express-etcd][express-etcd-url] An [etcd](https://github.com/stianeikeland/node-etcd) based session store.
+
+[express-etcd-url]: https://www.npmjs.com/package/express-etcd
+[express-etcd-image]: https://badgen.net/github/stars/gildean/express-etcd?label=%E2%98%85
+
+[![★][express-mysql-session-image] express-mysql-session][express-mysql-session-url] A session store using native
+[MySQL](https://www.mysql.com/) via the [node-mysql](https://github.com/felixge/node-mysql) module.
+
+[express-mysql-session-url]: https://www.npmjs.com/package/express-mysql-session
+[express-mysql-session-image]: https://badgen.net/github/stars/chill117/express-mysql-session?label=%E2%98%85
+
+[![★][express-nedb-session-image] express-nedb-session][express-nedb-session-url] A NeDB-based session store.
+
+[express-nedb-session-url]: https://www.npmjs.com/package/express-nedb-session
+[express-nedb-session-image]: https://badgen.net/github/stars/louischatriot/express-nedb-session?label=%E2%98%85
+
+[![★][express-oracle-session-image] express-oracle-session][express-oracle-session-url] A session store using native
+[oracle](https://www.oracle.com/) via the [node-oracledb](https://www.npmjs.com/package/oracledb) module.
+
+[express-oracle-session-url]: https://www.npmjs.com/package/express-oracle-session
+[express-oracle-session-image]: https://badgen.net/github/stars/slumber86/express-oracle-session?label=%E2%98%85
+
+[![★][express-session-cache-manager-image] express-session-cache-manager][express-session-cache-manager-url]
+A store that implements [cache-manager](https://www.npmjs.com/package/cache-manager), which supports
+a [variety of storage types](https://www.npmjs.com/package/cache-manager#store-engines).
+
+[express-session-cache-manager-url]: https://www.npmjs.com/package/express-session-cache-manager
+[express-session-cache-manager-image]: https://badgen.net/github/stars/theogravity/express-session-cache-manager?label=%E2%98%85
+
+[![★][express-session-etcd3-image] express-session-etcd3][express-session-etcd3-url] An [etcd3](https://github.com/mixer/etcd3) based session store.
+
+[express-session-etcd3-url]: https://www.npmjs.com/package/express-session-etcd3
+[express-session-etcd3-image]: https://badgen.net/github/stars/willgm/express-session-etcd3?label=%E2%98%85
+
+[![★][express-session-level-image] express-session-level][express-session-level-url] A [LevelDB](https://github.com/Level/levelup) based session store.
+
+[express-session-level-url]: https://www.npmjs.com/package/express-session-level
+[express-session-level-image]: https://badgen.net/github/stars/tgohn/express-session-level?label=%E2%98%85
+
+[![★][express-session-rsdb-image] express-session-rsdb][express-session-rsdb-url] Session store based on Rocket-Store: A very simple, super fast and yet powerful, flat file database.
+
+[express-session-rsdb-url]: https://www.npmjs.com/package/express-session-rsdb
+[express-session-rsdb-image]: https://badgen.net/github/stars/paragi/express-session-rsdb?label=%E2%98%85
+
+[![★][express-sessions-image] express-sessions][express-sessions-url] A session store supporting both MongoDB and Redis.
+
+[express-sessions-url]: https://www.npmjs.com/package/express-sessions
+[express-sessions-image]: https://badgen.net/github/stars/konteck/express-sessions?label=%E2%98%85
+
+[![★][firestore-store-image] firestore-store][firestore-store-url] A [Firestore](https://github.com/hendrysadrak/firestore-store)-based session store.
+
+[firestore-store-url]: https://www.npmjs.com/package/firestore-store
+[firestore-store-image]: https://badgen.net/github/stars/hendrysadrak/firestore-store?label=%E2%98%85
+
+[![★][fortune-session-image] fortune-session][fortune-session-url] A [Fortune.js](https://github.com/fortunejs/fortune)
+based session store. Supports all backends supported by Fortune (MongoDB, Redis, Postgres, NeDB).
+
+[fortune-session-url]: https://www.npmjs.com/package/fortune-session
+[fortune-session-image]: https://badgen.net/github/stars/aliceklipper/fortune-session?label=%E2%98%85
+
+[![★][hazelcast-store-image] hazelcast-store][hazelcast-store-url] A Hazelcast-based session store built on the [Hazelcast Node Client](https://www.npmjs.com/package/hazelcast-client).
+
+[hazelcast-store-url]: https://www.npmjs.com/package/hazelcast-store
+[hazelcast-store-image]: https://badgen.net/github/stars/jackspaniel/hazelcast-store?label=%E2%98%85
+
+[![★][level-session-store-image] level-session-store][level-session-store-url] A LevelDB-based session store.
+
+[level-session-store-url]: https://www.npmjs.com/package/level-session-store
+[level-session-store-image]: https://badgen.net/github/stars/toddself/level-session-store?label=%E2%98%85
+
+[![★][lowdb-session-store-image] lowdb-session-store][lowdb-session-store-url] A [lowdb](https://www.npmjs.com/package/lowdb)-based session store.
+
+[lowdb-session-store-url]: https://www.npmjs.com/package/lowdb-session-store
+[lowdb-session-store-image]: https://badgen.net/github/stars/fhellwig/lowdb-session-store?label=%E2%98%85
+
+[![★][medea-session-store-image] medea-session-store][medea-session-store-url] A Medea-based session store.
+
+[medea-session-store-url]: https://www.npmjs.com/package/medea-session-store
+[medea-session-store-image]: https://badgen.net/github/stars/BenjaminVadant/medea-session-store?label=%E2%98%85
+
+[![★][memorystore-image] memorystore][memorystore-url] A memory session store made for production.
+
+[memorystore-url]: https://www.npmjs.com/package/memorystore
+[memorystore-image]: https://badgen.net/github/stars/roccomuso/memorystore?label=%E2%98%85
+
+[![★][mssql-session-store-image] mssql-session-store][mssql-session-store-url] A SQL Server-based session store.
+
+[mssql-session-store-url]: https://www.npmjs.com/package/mssql-session-store
+[mssql-session-store-image]: https://badgen.net/github/stars/jwathen/mssql-session-store?label=%E2%98%85
+
+[![★][nedb-session-store-image] nedb-session-store][nedb-session-store-url] An alternate NeDB-based (either in-memory or file-persisted) session store.
+
+[nedb-session-store-url]: https://www.npmjs.com/package/nedb-session-store
+[nedb-session-store-image]: https://badgen.net/github/stars/JamesMGreene/nedb-session-store?label=%E2%98%85
+
+[![★][@quixo3/prisma-session-store-image] @quixo3/prisma-session-store][@quixo3/prisma-session-store-url] A session store for the [Prisma Framework](https://www.prisma.io).
+
+[@quixo3/prisma-session-store-url]: https://www.npmjs.com/package/@quixo3/prisma-session-store
+[@quixo3/prisma-session-store-image]: https://badgen.net/github/stars/kleydon/prisma-session-store?label=%E2%98%85
+
+[![★][restsession-image] restsession][restsession-url] Store sessions utilizing a RESTful API
+
+[restsession-url]: https://www.npmjs.com/package/restsession
+[restsession-image]: https://badgen.net/github/stars/jankal/restsession?label=%E2%98%85
+
+[![★][sequelstore-connect-image] sequelstore-connect][sequelstore-connect-url] A session store using [Sequelize.js](http://sequelizejs.com/).
+
+[sequelstore-connect-url]: https://www.npmjs.com/package/sequelstore-connect
+[sequelstore-connect-image]: https://badgen.net/github/stars/MattMcFarland/sequelstore-connect?label=%E2%98%85
+
+[![★][session-file-store-image] session-file-store][session-file-store-url] A file system-based session store.
+
+[session-file-store-url]: https://www.npmjs.com/package/session-file-store
+[session-file-store-image]: https://badgen.net/github/stars/valery-barysok/session-file-store?label=%E2%98%85
+
+[![★][session-pouchdb-store-image] session-pouchdb-store][session-pouchdb-store-url] Session store for PouchDB / CouchDB. Accepts embedded, custom, or remote PouchDB instance and realtime synchronization.
+
+[session-pouchdb-store-url]: https://www.npmjs.com/package/session-pouchdb-store
+[session-pouchdb-store-image]: https://badgen.net/github/stars/solzimer/session-pouchdb-store?label=%E2%98%85
+
+[![★][@cyclic.sh/session-store-image] @cyclic.sh/session-store][@cyclic.sh/session-store-url] A DynamoDB-based session store for [Cyclic.sh](https://www.cyclic.sh/) apps.
+
+[@cyclic.sh/session-store-url]: https://www.npmjs.com/package/@cyclic.sh/session-store
+[@cyclic.sh/session-store-image]: https://badgen.net/github/stars/cyclic-software/session-store?label=%E2%98%85
+
+[![★][@databunker/session-store-image] @databunker/session-store][@databunker/session-store-url] A [Databunker](https://databunker.org/)-based encrypted session store.
+
+[@databunker/session-store-url]: https://www.npmjs.com/package/@databunker/session-store
+[@databunker/session-store-image]: https://badgen.net/github/stars/securitybunker/databunker-session-store?label=%E2%98%85
+
+[![★][sessionstore-image] sessionstore][sessionstore-url] A session store that works with various databases.
+
+[sessionstore-url]: https://www.npmjs.com/package/sessionstore
+[sessionstore-image]: https://badgen.net/github/stars/adrai/sessionstore?label=%E2%98%85
+
+[![★][tch-nedb-session-image] tch-nedb-session][tch-nedb-session-url] A file system session store based on NeDB.
+
+[tch-nedb-session-url]: https://www.npmjs.com/package/tch-nedb-session
+[tch-nedb-session-image]: https://badgen.net/github/stars/tomaschyly/NeDBSession?label=%E2%98%85
+
+## Examples
+
+### View counter
+
+A simple example using `express-session` to store page views for a user.
+
+```js
+var express = require('express')
+var parseurl = require('parseurl')
+var session = require('express-session')
+
+var app = express()
+
+app.use(session({
+  secret: 'keyboard cat',
+  resave: false,
+  saveUninitialized: true
+}))
+
+app.use(function (req, res, next) {
+  if (!req.session.views) {
+    req.session.views = {}
+  }
+
+  // get the url pathname
+  var pathname = parseurl(req).pathname
+
+  // count the views
+  req.session.views[pathname] = (req.session.views[pathname] || 0) + 1
+
+  next()
+})
+
+app.get('/foo', function (req, res, next) {
+  res.send('you viewed this page ' + req.session.views['/foo'] + ' times')
+})
+
+app.get('/bar', function (req, res, next) {
+  res.send('you viewed this page ' + req.session.views['/bar'] + ' times')
+})
+
+app.listen(3000)
+```
+
+### User login
+
+A simple example using `express-session` to keep a user log in session.
+
+```js
+var escapeHtml = require('escape-html')
+var express = require('express')
+var session = require('express-session')
+
+var app = express()
+
+app.use(session({
+  secret: 'keyboard cat',
+  resave: false,
+  saveUninitialized: true
+}))
+
+// middleware to test if authenticated
+function isAuthenticated (req, res, next) {
+  if (req.session.user) next()
+  else next('route')
+}
+
+app.get('/', isAuthenticated, function (req, res) {
+  // this is only called when there is an authentication user due to isAuthenticated
+  res.send('hello, ' + escapeHtml(req.session.user) + '!' +
+    ' <a href="/logout">Logout</a>')
+})
+
+app.get('/', function (req, res) {
+  res.send('<form action="/login" method="post">' +
+    'Username: <input name="user"><br>' +
+    'Password: <input name="pass" type="password"><br>' +
+    '<input type="submit" text="Login"></form>')
+})
+
+app.post('/login', express.urlencoded({ extended: false }), function (req, res) {
+  // login logic to validate req.body.user and req.body.pass
+  // would be implemented here. for this example any combo works
+
+  // regenerate the session, which is good practice to help
+  // guard against forms of session fixation
+  req.session.regenerate(function (err) {
+    if (err) next(err)
+
+    // store user information in session, typically a user id
+    req.session.user = req.body.user
+
+    // save the session before redirection to ensure page
+    // load does not happen before session is saved
+    req.session.save(function (err) {
+      if (err) return next(err)
+      res.redirect('/')
+    })
+  })
+})
+
+app.get('/logout', function (req, res, next) {
+  // logout logic
+
+  // clear the user from the session object and save.
+  // this will ensure that re-using the old session id
+  // does not have a logged in user
+  req.session.user = null
+  req.session.save(function (err) {
+    if (err) next(err)
+
+    // regenerate the session, which is good practice to help
+    // guard against forms of session fixation
+    req.session.regenerate(function (err) {
+      if (err) next(err)
+      res.redirect('/')
+    })
+  })
+})
+
+app.listen(3000)
+```
+
+## Debugging
+
+This module uses the [debug](https://www.npmjs.com/package/debug) module
+internally to log information about session operations.
+
+To see all the internal logs, set the `DEBUG` environment variable to
+`express-session` when launching your app (`npm start`, in this example):
+
+```sh
+$ DEBUG=express-session npm start
+```
+
+On Windows, use the corresponding command;
+
+```sh
+> set DEBUG=express-session & npm start
+```
+
+## License
+
+[MIT](LICENSE)
+
+[rfc-6265bis-03-4.1.2.7]: https://tools.ietf.org/html/draft-ietf-httpbis-rfc6265bis-03#section-4.1.2.7
+[rfc-cutler-httpbis-partitioned-cookies]: https://tools.ietf.org/html/draft-cutler-httpbis-partitioned-cookies/
+[rfc-west-cookie-priority-00-4.1]: https://tools.ietf.org/html/draft-west-cookie-priority-00#section-4.1
+[ci-image]: https://badgen.net/github/checks/expressjs/session/master?label=ci
+[ci-url]: https://github.com/expressjs/session/actions?query=workflow%3Aci
+[coveralls-image]: https://badgen.net/coveralls/c/github/expressjs/session/master
+[coveralls-url]: https://coveralls.io/r/expressjs/session?branch=master
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/express-session
+[npm-url]: https://npmjs.org/package/express-session
+[npm-version-image]: https://badgen.net/npm/v/express-session
diff --git a/server/node_modules/express-session/index.js b/server/node_modules/express-session/index.js
new file mode 100644
index 0000000..1a50931
--- /dev/null
+++ b/server/node_modules/express-session/index.js
@@ -0,0 +1,700 @@
+/*!
+ * express-session
+ * Copyright(c) 2010 Sencha Inc.
+ * Copyright(c) 2011 TJ Holowaychuk
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var Buffer = require('safe-buffer').Buffer
+var cookie = require('cookie');
+var crypto = require('crypto')
+var debug = require('debug')('express-session');
+var deprecate = require('depd')('express-session');
+var onHeaders = require('on-headers')
+var parseUrl = require('parseurl');
+var signature = require('cookie-signature')
+var uid = require('uid-safe').sync
+
+var Cookie = require('./session/cookie')
+var MemoryStore = require('./session/memory')
+var Session = require('./session/session')
+var Store = require('./session/store')
+
+// environment
+
+var env = process.env.NODE_ENV;
+
+/**
+ * Expose the middleware.
+ */
+
+exports = module.exports = session;
+
+/**
+ * Expose constructors.
+ */
+
+exports.Store = Store;
+exports.Cookie = Cookie;
+exports.Session = Session;
+exports.MemoryStore = MemoryStore;
+
+/**
+ * Warning message for `MemoryStore` usage in production.
+ * @private
+ */
+
+var warning = 'Warning: connect.session() MemoryStore is not\n'
+  + 'designed for a production environment, as it will leak\n'
+  + 'memory, and will not scale past a single process.';
+
+/**
+ * Node.js 0.8+ async implementation.
+ * @private
+ */
+
+/* istanbul ignore next */
+var defer = typeof setImmediate === 'function'
+  ? setImmediate
+  : function(fn){ process.nextTick(fn.bind.apply(fn, arguments)) }
+
+/**
+ * Setup session store with the given `options`.
+ *
+ * @param {Object} [options]
+ * @param {Object|Function} [options.cookie] Options for cookie
+ * @param {Function} [options.genid]
+ * @param {String} [options.name=connect.sid] Session ID cookie name
+ * @param {Boolean} [options.proxy]
+ * @param {Boolean} [options.resave] Resave unmodified sessions back to the store
+ * @param {Boolean} [options.rolling] Enable/disable rolling session expiration
+ * @param {Boolean} [options.saveUninitialized] Save uninitialized sessions to the store
+ * @param {String|Array} [options.secret] Secret for signing session ID
+ * @param {Object} [options.store=MemoryStore] Session store
+ * @param {String} [options.unset]
+ * @return {Function} middleware
+ * @public
+ */
+
+function session(options) {
+  var opts = options || {}
+
+  // get the cookie options
+  var cookieOptions = opts.cookie || {}
+
+  // get the session id generate function
+  var generateId = opts.genid || generateSessionId
+
+  // get the session cookie name
+  var name = opts.name || opts.key || 'connect.sid'
+
+  // get the session store
+  var store = opts.store || new MemoryStore()
+
+  // get the trust proxy setting
+  var trustProxy = opts.proxy
+
+  // get the resave session option
+  var resaveSession = opts.resave;
+
+  // get the rolling session option
+  var rollingSessions = Boolean(opts.rolling)
+
+  // get the save uninitialized session option
+  var saveUninitializedSession = opts.saveUninitialized
+
+  // get the cookie signing secret
+  var secret = opts.secret
+
+  if (typeof generateId !== 'function') {
+    throw new TypeError('genid option must be a function');
+  }
+
+  if (resaveSession === undefined) {
+    deprecate('undefined resave option; provide resave option');
+    resaveSession = true;
+  }
+
+  if (saveUninitializedSession === undefined) {
+    deprecate('undefined saveUninitialized option; provide saveUninitialized option');
+    saveUninitializedSession = true;
+  }
+
+  if (opts.unset && opts.unset !== 'destroy' && opts.unset !== 'keep') {
+    throw new TypeError('unset option must be "destroy" or "keep"');
+  }
+
+  // TODO: switch to "destroy" on next major
+  var unsetDestroy = opts.unset === 'destroy'
+
+  if (Array.isArray(secret) && secret.length === 0) {
+    throw new TypeError('secret option array must contain one or more strings');
+  }
+
+  if (secret && !Array.isArray(secret)) {
+    secret = [secret];
+  }
+
+  if (!secret) {
+    deprecate('req.secret; provide secret option');
+  }
+
+  // notify user that this store is not
+  // meant for a production environment
+  /* istanbul ignore next: not tested */
+  if (env === 'production' && store instanceof MemoryStore) {
+    console.warn(warning);
+  }
+
+  // generates the new session
+  store.generate = function(req){
+    req.sessionID = generateId(req);
+    req.session = new Session(req);
+    req.session.cookie = new Cookie(typeof cookieOptions === 'function' ? cookieOptions(req) : cookieOptions);
+
+    var isSecure = issecure(req, trustProxy);
+
+    if (cookieOptions.secure === 'auto') {
+      req.session.cookie.secure = isSecure;
+    }
+
+    if (cookieOptions.sameSite === 'auto') {
+      req.session.cookie.sameSite = isSecure ? 'none' : 'lax';
+    }
+  };
+
+  var storeImplementsTouch = typeof store.touch === 'function';
+
+  // register event listeners for the store to track readiness
+  var storeReady = true
+  store.on('disconnect', function ondisconnect() {
+    storeReady = false
+  })
+  store.on('connect', function onconnect() {
+    storeReady = true
+  })
+
+  return function session(req, res, next) {
+    // self-awareness
+    if (req.session) {
+      next()
+      return
+    }
+
+    // Handle connection as if there is no session if
+    // the store has temporarily disconnected etc
+    if (!storeReady) {
+      debug('store is disconnected')
+      next()
+      return
+    }
+
+    // pathname mismatch
+    var originalPath = parseUrl.original(req).pathname || '/'
+    var resolvedCookieOptions = typeof cookieOptions === 'function' ? cookieOptions(req) : cookieOptions
+    if (originalPath.indexOf(resolvedCookieOptions.path || '/') !== 0) {
+      debug('pathname mismatch')
+      next()
+      return
+    }
+
+    // ensure a secret is available or bail
+    if (!secret && !req.secret) {
+      next(new Error('secret option required for sessions'));
+      return;
+    }
+
+    // backwards compatibility for signed cookies
+    // req.secret is passed from the cookie parser middleware
+    var secrets = secret || [req.secret];
+
+    var originalHash;
+    var originalId;
+    var savedHash;
+    var touched = false
+
+    // expose store
+    req.sessionStore = store;
+
+    // get the session ID from the cookie
+    var cookieId = req.sessionID = getcookie(req, name, secrets);
+
+    // set-cookie
+    onHeaders(res, function(){
+      if (!req.session) {
+        debug('no session');
+        return;
+      }
+
+      if (!shouldSetCookie(req)) {
+        return;
+      }
+
+      // only send secure cookies via https
+      if (req.session.cookie.secure && !issecure(req, trustProxy)) {
+        debug('not secured');
+        return;
+      }
+
+      if (!touched) {
+        // touch session
+        req.session.touch()
+        touched = true
+      }
+
+      // set cookie
+      try {
+        setcookie(res, name, req.sessionID, secrets[0], req.session.cookie.data)
+      } catch (err) {
+        defer(next, err)
+      }
+    });
+
+    // proxy end() to commit the session
+    var _end = res.end;
+    var _write = res.write;
+    var ended = false;
+    res.end = function end(chunk, encoding) {
+      if (ended) {
+        return false;
+      }
+
+      ended = true;
+
+      var ret;
+      var sync = true;
+
+      function writeend() {
+        if (sync) {
+          ret = _end.call(res, chunk, encoding);
+          sync = false;
+          return;
+        }
+
+        _end.call(res);
+      }
+
+      function writetop() {
+        if (!sync) {
+          return ret;
+        }
+
+        if (!res._header) {
+          res._implicitHeader()
+        }
+
+        if (chunk == null) {
+          ret = true;
+          return ret;
+        }
+
+        var contentLength = Number(res.getHeader('Content-Length'));
+
+        if (!isNaN(contentLength) && contentLength > 0) {
+          // measure chunk
+          chunk = !Buffer.isBuffer(chunk)
+            ? Buffer.from(chunk, encoding)
+            : chunk;
+          encoding = undefined;
+
+          if (chunk.length !== 0) {
+            debug('split response');
+            ret = _write.call(res, chunk.slice(0, chunk.length - 1));
+            chunk = chunk.slice(chunk.length - 1, chunk.length);
+            return ret;
+          }
+        }
+
+        ret = _write.call(res, chunk, encoding);
+        sync = false;
+
+        return ret;
+      }
+
+      if (shouldDestroy(req)) {
+        // destroy session
+        debug('destroying');
+        store.destroy(req.sessionID, function ondestroy(err) {
+          if (err) {
+            defer(next, err);
+          }
+
+          debug('destroyed');
+          writeend();
+        });
+
+        return writetop();
+      }
+
+      // no session to save
+      if (!req.session) {
+        debug('no session');
+        return _end.call(res, chunk, encoding);
+      }
+
+      if (!touched) {
+        // touch session
+        req.session.touch()
+        touched = true
+      }
+
+      if (shouldSave(req)) {
+        req.session.save(function onsave(err) {
+          if (err) {
+            defer(next, err);
+          }
+
+          writeend();
+        });
+
+        return writetop();
+      } else if (storeImplementsTouch && shouldTouch(req)) {
+        // store implements touch method
+        debug('touching');
+        store.touch(req.sessionID, req.session, function ontouch(err) {
+          if (err) {
+            defer(next, err);
+          }
+
+          debug('touched');
+          writeend();
+        });
+
+        return writetop();
+      }
+
+      return _end.call(res, chunk, encoding);
+    };
+
+    // generate the session
+    function generate() {
+      store.generate(req);
+      originalId = req.sessionID;
+      originalHash = hash(req.session);
+      wrapmethods(req.session);
+    }
+
+    // inflate the session
+    function inflate (req, sess) {
+      store.createSession(req, sess)
+      originalId = req.sessionID
+      originalHash = hash(sess)
+
+      if (!resaveSession) {
+        savedHash = originalHash
+      }
+
+      wrapmethods(req.session)
+    }
+
+    function rewrapmethods (sess, callback) {
+      return function () {
+        if (req.session !== sess) {
+          wrapmethods(req.session)
+        }
+
+        callback.apply(this, arguments)
+      }
+    }
+
+    // wrap session methods
+    function wrapmethods(sess) {
+      var _reload = sess.reload
+      var _save = sess.save;
+
+      function reload(callback) {
+        debug('reloading %s', this.id)
+        _reload.call(this, rewrapmethods(this, callback))
+      }
+
+      function save() {
+        debug('saving %s', this.id);
+        savedHash = hash(this);
+        _save.apply(this, arguments);
+      }
+
+      Object.defineProperty(sess, 'reload', {
+        configurable: true,
+        enumerable: false,
+        value: reload,
+        writable: true
+      })
+
+      Object.defineProperty(sess, 'save', {
+        configurable: true,
+        enumerable: false,
+        value: save,
+        writable: true
+      });
+    }
+
+    // check if session has been modified
+    function isModified(sess) {
+      return originalId !== sess.id || originalHash !== hash(sess);
+    }
+
+    // check if session has been saved
+    function isSaved(sess) {
+      return originalId === sess.id && savedHash === hash(sess);
+    }
+
+    // determine if session should be destroyed
+    function shouldDestroy(req) {
+      return req.sessionID && unsetDestroy && req.session == null;
+    }
+
+    // determine if session should be saved to store
+    function shouldSave(req) {
+      // cannot set cookie without a session ID
+      if (typeof req.sessionID !== 'string') {
+        debug('session ignored because of bogus req.sessionID %o', req.sessionID);
+        return false;
+      }
+
+      return !saveUninitializedSession && !savedHash && cookieId !== req.sessionID
+        ? isModified(req.session)
+        : !isSaved(req.session)
+    }
+
+    // determine if session should be touched
+    function shouldTouch(req) {
+      // cannot set cookie without a session ID
+      if (typeof req.sessionID !== 'string') {
+        debug('session ignored because of bogus req.sessionID %o', req.sessionID);
+        return false;
+      }
+
+      return cookieId === req.sessionID && !shouldSave(req);
+    }
+
+    // determine if cookie should be set on response
+    function shouldSetCookie(req) {
+      // cannot set cookie without a session ID
+      if (typeof req.sessionID !== 'string') {
+        return false;
+      }
+
+      return cookieId !== req.sessionID
+        ? saveUninitializedSession || isModified(req.session)
+        : rollingSessions || req.session.cookie.expires != null && isModified(req.session);
+    }
+
+    // generate a session if the browser doesn't send a sessionID
+    if (!req.sessionID) {
+      debug('no SID sent, generating session');
+      generate();
+      next();
+      return;
+    }
+
+    // generate the session object
+    debug('fetching %s', req.sessionID);
+    store.get(req.sessionID, function(err, sess){
+      // error handling
+      if (err && err.code !== 'ENOENT') {
+        debug('error %j', err);
+        next(err)
+        return
+      }
+
+      try {
+        if (err || !sess) {
+          debug('no session found')
+          generate()
+        } else {
+          debug('session found')
+          inflate(req, sess)
+        }
+      } catch (e) {
+        next(e)
+        return
+      }
+
+      next()
+    });
+  };
+};
+
+/**
+ * Generate a session ID for a new session.
+ *
+ * @return {String}
+ * @private
+ */
+
+function generateSessionId() {
+  return uid(24);
+}
+
+/**
+ * Get the session ID cookie from request.
+ *
+ * @return {string}
+ * @private
+ */
+
+function getcookie(req, name, secrets) {
+  var header = req.headers.cookie;
+  var raw;
+  var val;
+
+  // read from cookie header
+  if (header) {
+    var cookies = cookie.parse(header);
+
+    raw = cookies[name];
+
+    if (raw) {
+      if (raw.substr(0, 2) === 's:') {
+        val = unsigncookie(raw.slice(2), secrets);
+
+        if (val === false) {
+          debug('cookie signature invalid');
+          val = undefined;
+        }
+      } else {
+        debug('cookie unsigned')
+      }
+    }
+  }
+
+  // back-compat read from cookieParser() signedCookies data
+  if (!val && req.signedCookies) {
+    val = req.signedCookies[name];
+
+    if (val) {
+      deprecate('cookie should be available in req.headers.cookie');
+    }
+  }
+
+  // back-compat read from cookieParser() cookies data
+  if (!val && req.cookies) {
+    raw = req.cookies[name];
+
+    if (raw) {
+      if (raw.substr(0, 2) === 's:') {
+        val = unsigncookie(raw.slice(2), secrets);
+
+        if (val) {
+          deprecate('cookie should be available in req.headers.cookie');
+        }
+
+        if (val === false) {
+          debug('cookie signature invalid');
+          val = undefined;
+        }
+      } else {
+        debug('cookie unsigned')
+      }
+    }
+  }
+
+  return val;
+}
+
+/**
+ * Hash the given `sess` object omitting changes to `.cookie`.
+ *
+ * @param {Object} sess
+ * @return {String}
+ * @private
+ */
+
+function hash(sess) {
+  // serialize
+  var str = JSON.stringify(sess, function (key, val) {
+    // ignore sess.cookie property
+    if (this === sess && key === 'cookie') {
+      return
+    }
+
+    return val
+  })
+
+  // hash
+  return crypto
+    .createHash('sha1')
+    .update(str, 'utf8')
+    .digest('hex')
+}
+
+/**
+ * Determine if request is secure.
+ *
+ * @param {Object} req
+ * @param {Boolean} [trustProxy]
+ * @return {Boolean}
+ * @private
+ */
+
+function issecure(req, trustProxy) {
+  // socket is https server
+  if (req.connection && req.connection.encrypted) {
+    return true;
+  }
+
+  // do not trust proxy
+  if (trustProxy === false) {
+    return false;
+  }
+
+  // no explicit trust; try req.secure from express
+  if (trustProxy !== true) {
+    return req.secure === true
+  }
+
+  // read the proto from x-forwarded-proto header
+  var header = req.headers['x-forwarded-proto'] || '';
+  var index = header.indexOf(',');
+  var proto = index !== -1
+    ? header.substr(0, index).toLowerCase().trim()
+    : header.toLowerCase().trim()
+
+  return proto === 'https';
+}
+
+/**
+ * Set cookie on response.
+ *
+ * @private
+ */
+
+function setcookie(res, name, val, secret, options) {
+  var signed = 's:' + signature.sign(val, secret);
+  var data = cookie.serialize(name, signed, options);
+
+  debug('set-cookie %s', data);
+
+  var prev = res.getHeader('Set-Cookie') || []
+  var header = Array.isArray(prev) ? prev.concat(data) : [prev, data];
+
+  res.setHeader('Set-Cookie', header)
+}
+
+/**
+ * Verify and decode the given `val` with `secrets`.
+ *
+ * @param {String} val
+ * @param {Array} secrets
+ * @returns {String|Boolean}
+ * @private
+ */
+function unsigncookie(val, secrets) {
+  for (var i = 0; i < secrets.length; i++) {
+    var result = signature.unsign(val, secrets[i]);
+
+    if (result !== false) {
+      return result;
+    }
+  }
+
+  return false;
+}
diff --git a/server/node_modules/express-session/package.json b/server/node_modules/express-session/package.json
new file mode 100644
index 0000000..3638779
--- /dev/null
+++ b/server/node_modules/express-session/package.json
@@ -0,0 +1,50 @@
+{
+  "name": "express-session",
+  "version": "1.19.0",
+  "description": "Simple session middleware for Express",
+  "author": "TJ Holowaychuk <tj@vision-media.ca> (http://tjholowaychuk.com)",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Joe Wagner <njwjs722@gmail.com>"
+  ],
+  "repository": "expressjs/session",
+  "funding": {
+    "type": "opencollective",
+    "url": "https://opencollective.com/express"
+  },
+  "license": "MIT",
+  "dependencies": {
+    "cookie": "~0.7.2",
+    "cookie-signature": "~1.0.7",
+    "debug": "~2.6.9",
+    "depd": "~2.0.0",
+    "on-headers": "~1.1.0",
+    "parseurl": "~1.3.3",
+    "safe-buffer": "~5.2.1",
+    "uid-safe": "~2.1.5"
+  },
+  "devDependencies": {
+    "after": "0.8.2",
+    "cookie-parser": "1.4.6",
+    "eslint": "8.56.0",
+    "eslint-plugin-markdown": "3.0.1",
+    "express": "4.17.3",
+    "mocha": "10.8.2",
+    "nyc": "15.1.0",
+    "supertest": "6.3.4"
+  },
+  "files": [
+    "session/",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8.0"
+  },
+  "scripts": {
+    "lint": "eslint . && node ./scripts/lint-readme.js",
+    "test": "./test/support/gencert.sh && mocha --require test/support/env --check-leaks --no-exit --reporter spec test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc npm test",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  }
+}
diff --git a/server/node_modules/express-session/session/cookie.js b/server/node_modules/express-session/session/cookie.js
new file mode 100644
index 0000000..8bb5907
--- /dev/null
+++ b/server/node_modules/express-session/session/cookie.js
@@ -0,0 +1,152 @@
+/*!
+ * Connect - session - Cookie
+ * Copyright(c) 2010 Sencha Inc.
+ * Copyright(c) 2011 TJ Holowaychuk
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ */
+
+var cookie = require('cookie')
+var deprecate = require('depd')('express-session')
+
+/**
+ * Initialize a new `Cookie` with the given `options`.
+ *
+ * @param {IncomingMessage} req
+ * @param {Object} options
+ * @api private
+ */
+
+var Cookie = module.exports = function Cookie(options) {
+  this.path = '/';
+  this.maxAge = null;
+  this.httpOnly = true;
+
+  if (options) {
+    if (typeof options !== 'object') {
+      throw new TypeError('argument options must be a object')
+    }
+
+    for (var key in options) {
+      if (key !== 'data') {
+        this[key] = options[key]
+      }
+    }
+  }
+
+  if (this.originalMaxAge === undefined || this.originalMaxAge === null) {
+    this.originalMaxAge = this.maxAge
+  }
+};
+
+/*!
+ * Prototype.
+ */
+
+Cookie.prototype = {
+
+  /**
+   * Set expires `date`.
+   *
+   * @param {Date} date
+   * @api public
+   */
+
+  set expires(date) {
+    this._expires = date;
+    this.originalMaxAge = this.maxAge;
+  },
+
+  /**
+   * Get expires `date`.
+   *
+   * @return {Date}
+   * @api public
+   */
+
+  get expires() {
+    return this._expires;
+  },
+
+  /**
+   * Set expires via max-age in `ms`.
+   *
+   * @param {Number} ms
+   * @api public
+   */
+
+  set maxAge(ms) {
+    if (ms && typeof ms !== 'number' && !(ms instanceof Date)) {
+      throw new TypeError('maxAge must be a number or Date')
+    }
+
+    if (ms instanceof Date) {
+      deprecate('maxAge as Date; pass number of milliseconds instead')
+    }
+
+    this.expires = typeof ms === 'number'
+      ? new Date(Date.now() + ms)
+      : ms;
+  },
+
+  /**
+   * Get expires max-age in `ms`.
+   *
+   * @return {Number}
+   * @api public
+   */
+
+  get maxAge() {
+    return this.expires instanceof Date
+      ? this.expires.valueOf() - Date.now()
+      : this.expires;
+  },
+
+  /**
+   * Return cookie data object.
+   *
+   * @return {Object}
+   * @api private
+   */
+
+  get data() {
+    return {
+      originalMaxAge: this.originalMaxAge,
+      partitioned: this.partitioned,
+      priority: this.priority
+      , expires: this._expires
+      , secure: this.secure
+      , httpOnly: this.httpOnly
+      , domain: this.domain
+      , path: this.path
+      , sameSite: this.sameSite
+    }
+  },
+
+  /**
+   * Return a serialized cookie string.
+   *
+   * @return {String}
+   * @api public
+   */
+
+  serialize: function(name, val){
+    return cookie.serialize(name, val, this.data);
+  },
+
+  /**
+   * Return JSON representation of this cookie.
+   *
+   * @return {Object}
+   * @api private
+   */
+
+  toJSON: function(){
+    return this.data;
+  }
+};
diff --git a/server/node_modules/express-session/session/memory.js b/server/node_modules/express-session/session/memory.js
new file mode 100644
index 0000000..11ed686
--- /dev/null
+++ b/server/node_modules/express-session/session/memory.js
@@ -0,0 +1,187 @@
+/*!
+ * express-session
+ * Copyright(c) 2010 Sencha Inc.
+ * Copyright(c) 2011 TJ Holowaychuk
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var Store = require('./store')
+var util = require('util')
+
+/**
+ * Shim setImmediate for node.js < 0.10
+ * @private
+ */
+
+/* istanbul ignore next */
+var defer = typeof setImmediate === 'function'
+  ? setImmediate
+  : function(fn){ process.nextTick(fn.bind.apply(fn, arguments)) }
+
+/**
+ * Module exports.
+ */
+
+module.exports = MemoryStore
+
+/**
+ * A session store in memory.
+ * @public
+ */
+
+function MemoryStore() {
+  Store.call(this)
+  this.sessions = Object.create(null)
+}
+
+/**
+ * Inherit from Store.
+ */
+
+util.inherits(MemoryStore, Store)
+
+/**
+ * Get all active sessions.
+ *
+ * @param {function} callback
+ * @public
+ */
+
+MemoryStore.prototype.all = function all(callback) {
+  var sessionIds = Object.keys(this.sessions)
+  var sessions = Object.create(null)
+
+  for (var i = 0; i < sessionIds.length; i++) {
+    var sessionId = sessionIds[i]
+    var session = getSession.call(this, sessionId)
+
+    if (session) {
+      sessions[sessionId] = session;
+    }
+  }
+
+  callback && defer(callback, null, sessions)
+}
+
+/**
+ * Clear all sessions.
+ *
+ * @param {function} callback
+ * @public
+ */
+
+MemoryStore.prototype.clear = function clear(callback) {
+  this.sessions = Object.create(null)
+  callback && defer(callback)
+}
+
+/**
+ * Destroy the session associated with the given session ID.
+ *
+ * @param {string} sessionId
+ * @public
+ */
+
+MemoryStore.prototype.destroy = function destroy(sessionId, callback) {
+  delete this.sessions[sessionId]
+  callback && defer(callback)
+}
+
+/**
+ * Fetch session by the given session ID.
+ *
+ * @param {string} sessionId
+ * @param {function} callback
+ * @public
+ */
+
+MemoryStore.prototype.get = function get(sessionId, callback) {
+  defer(callback, null, getSession.call(this, sessionId))
+}
+
+/**
+ * Commit the given session associated with the given sessionId to the store.
+ *
+ * @param {string} sessionId
+ * @param {object} session
+ * @param {function} callback
+ * @public
+ */
+
+MemoryStore.prototype.set = function set(sessionId, session, callback) {
+  this.sessions[sessionId] = JSON.stringify(session)
+  callback && defer(callback)
+}
+
+/**
+ * Get number of active sessions.
+ *
+ * @param {function} callback
+ * @public
+ */
+
+MemoryStore.prototype.length = function length(callback) {
+  this.all(function (err, sessions) {
+    if (err) return callback(err)
+    callback(null, Object.keys(sessions).length)
+  })
+}
+
+/**
+ * Touch the given session object associated with the given session ID.
+ *
+ * @param {string} sessionId
+ * @param {object} session
+ * @param {function} callback
+ * @public
+ */
+
+MemoryStore.prototype.touch = function touch(sessionId, session, callback) {
+  var currentSession = getSession.call(this, sessionId)
+
+  if (currentSession) {
+    // update expiration
+    currentSession.cookie = session.cookie
+    this.sessions[sessionId] = JSON.stringify(currentSession)
+  }
+
+  callback && defer(callback)
+}
+
+/**
+ * Get session from the store.
+ * @private
+ */
+
+function getSession(sessionId) {
+  var sess = this.sessions[sessionId]
+
+  if (!sess) {
+    return
+  }
+
+  // parse
+  sess = JSON.parse(sess)
+
+  if (sess.cookie) {
+    var expires = typeof sess.cookie.expires === 'string'
+      ? new Date(sess.cookie.expires)
+      : sess.cookie.expires
+
+    // destroy expired session
+    if (expires && expires <= Date.now()) {
+      delete this.sessions[sessionId]
+      return
+    }
+  }
+
+  return sess
+}
diff --git a/server/node_modules/express-session/session/session.js b/server/node_modules/express-session/session/session.js
new file mode 100644
index 0000000..fee7608
--- /dev/null
+++ b/server/node_modules/express-session/session/session.js
@@ -0,0 +1,143 @@
+/*!
+ * Connect - session - Session
+ * Copyright(c) 2010 Sencha Inc.
+ * Copyright(c) 2011 TJ Holowaychuk
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Expose Session.
+ */
+
+module.exports = Session;
+
+/**
+ * Create a new `Session` with the given request and `data`.
+ *
+ * @param {IncomingRequest} req
+ * @param {Object} data
+ * @api private
+ */
+
+function Session(req, data) {
+  Object.defineProperty(this, 'req', { value: req });
+  Object.defineProperty(this, 'id', { value: req.sessionID });
+
+  if (typeof data === 'object' && data !== null) {
+    // merge data into this, ignoring prototype properties
+    for (var prop in data) {
+      if (!(prop in this)) {
+        this[prop] = data[prop]
+      }
+    }
+  }
+}
+
+/**
+ * Update reset `.cookie.maxAge` to prevent
+ * the cookie from expiring when the
+ * session is still active.
+ *
+ * @return {Session} for chaining
+ * @api public
+ */
+
+defineMethod(Session.prototype, 'touch', function touch() {
+  return this.resetMaxAge();
+});
+
+/**
+ * Reset `.maxAge` to `.originalMaxAge`.
+ *
+ * @return {Session} for chaining
+ * @api public
+ */
+
+defineMethod(Session.prototype, 'resetMaxAge', function resetMaxAge() {
+  this.cookie.maxAge = this.cookie.originalMaxAge;
+  return this;
+});
+
+/**
+ * Save the session data with optional callback `fn(err)`.
+ *
+ * @param {Function} fn
+ * @return {Session} for chaining
+ * @api public
+ */
+
+defineMethod(Session.prototype, 'save', function save(fn) {
+  this.req.sessionStore.set(this.id, this, fn || function(){});
+  return this;
+});
+
+/**
+ * Re-loads the session data _without_ altering
+ * the maxAge properties. Invokes the callback `fn(err)`,
+ * after which time if no exception has occurred the
+ * `req.session` property will be a new `Session` object,
+ * although representing the same session.
+ *
+ * @param {Function} fn
+ * @return {Session} for chaining
+ * @api public
+ */
+
+defineMethod(Session.prototype, 'reload', function reload(fn) {
+  var req = this.req
+  var store = this.req.sessionStore
+
+  store.get(this.id, function(err, sess){
+    if (err) return fn(err);
+    if (!sess) return fn(new Error('failed to load session'));
+    store.createSession(req, sess);
+    fn();
+  });
+  return this;
+});
+
+/**
+ * Destroy `this` session.
+ *
+ * @param {Function} fn
+ * @return {Session} for chaining
+ * @api public
+ */
+
+defineMethod(Session.prototype, 'destroy', function destroy(fn) {
+  delete this.req.session;
+  this.req.sessionStore.destroy(this.id, fn);
+  return this;
+});
+
+/**
+ * Regenerate this request's session.
+ *
+ * @param {Function} fn
+ * @return {Session} for chaining
+ * @api public
+ */
+
+defineMethod(Session.prototype, 'regenerate', function regenerate(fn) {
+  this.req.sessionStore.regenerate(this.req, fn);
+  return this;
+});
+
+/**
+ * Helper function for creating a method on a prototype.
+ *
+ * @param {Object} obj
+ * @param {String} name
+ * @param {Function} fn
+ * @private
+ */
+function defineMethod(obj, name, fn) {
+  Object.defineProperty(obj, name, {
+    configurable: true,
+    enumerable: false,
+    value: fn,
+    writable: true
+  });
+};
diff --git a/server/node_modules/express-session/session/store.js b/server/node_modules/express-session/session/store.js
new file mode 100644
index 0000000..3793877
--- /dev/null
+++ b/server/node_modules/express-session/session/store.js
@@ -0,0 +1,102 @@
+/*!
+ * Connect - session - Store
+ * Copyright(c) 2010 Sencha Inc.
+ * Copyright(c) 2011 TJ Holowaychuk
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var Cookie = require('./cookie')
+var EventEmitter = require('events').EventEmitter
+var Session = require('./session')
+var util = require('util')
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = Store
+
+/**
+ * Abstract base class for session stores.
+ * @public
+ */
+
+function Store () {
+  EventEmitter.call(this)
+}
+
+/**
+ * Inherit from EventEmitter.
+ */
+
+util.inherits(Store, EventEmitter)
+
+/**
+ * Re-generate the given requests's session.
+ *
+ * @param {IncomingRequest} req
+ * @return {Function} fn
+ * @api public
+ */
+
+Store.prototype.regenerate = function(req, fn){
+  var self = this;
+  this.destroy(req.sessionID, function(err){
+    self.generate(req);
+    fn(err);
+  });
+};
+
+/**
+ * Load a `Session` instance via the given `sid`
+ * and invoke the callback `fn(err, sess)`.
+ *
+ * @param {String} sid
+ * @param {Function} fn
+ * @api public
+ */
+
+Store.prototype.load = function(sid, fn){
+  var self = this;
+  this.get(sid, function(err, sess){
+    if (err) return fn(err);
+    if (!sess) return fn();
+    var req = { sessionID: sid, sessionStore: self };
+    fn(null, self.createSession(req, sess))
+  });
+};
+
+/**
+ * Create session from JSON `sess` data.
+ *
+ * @param {IncomingRequest} req
+ * @param {Object} sess
+ * @return {Session}
+ * @api private
+ */
+
+Store.prototype.createSession = function(req, sess){
+  var expires = sess.cookie.expires
+  var originalMaxAge = sess.cookie.originalMaxAge
+
+  sess.cookie = new Cookie(sess.cookie);
+
+  if (typeof expires === 'string') {
+    // convert expires to a Date object
+    sess.cookie.expires = new Date(expires)
+  }
+
+  // keep originalMaxAge intact
+  sess.cookie.originalMaxAge = originalMaxAge
+
+  req.session = new Session(req, sess);
+  return req.session;
+};
diff --git a/server/node_modules/express/History.md b/server/node_modules/express/History.md
new file mode 100644
index 0000000..150c2ab
--- /dev/null
+++ b/server/node_modules/express/History.md
@@ -0,0 +1,3667 @@
+4.22.1 / 2025-12-01
+==========
+
+  * Revert security fix for [CVE-2024-51999](https://www.cve.org/CVERecord?id=CVE-2024-51999) ([GHSA-pj86-cfqh-vqx6](https://github.com/expressjs/express/security/advisories/GHSA-pj86-cfqh-vqx6))
+
+4.22.0 / 2025-12-01
+==========
+  * Security fix for [CVE-2024-51999](https://www.cve.org/CVERecord?id=CVE-2024-51999) ([GHSA-pj86-cfqh-vqx6](https://github.com/expressjs/express/security/advisories/GHSA-pj86-cfqh-vqx6))
+  * deps: use tilde notation for dependencies
+  * deps: qs@6.14.0
+
+4.21.2 / 2024-11-06
+==========
+
+  * deps: path-to-regexp@0.1.12
+    - Fix backtracking protection
+  * deps: path-to-regexp@0.1.11
+    - Throws an error on invalid path values
+
+4.21.1 / 2024-10-08
+==========
+
+  * Backported a fix for [CVE-2024-47764](https://nvd.nist.gov/vuln/detail/CVE-2024-47764)
+
+
+4.21.0 / 2024-09-11
+==========
+
+  * Deprecate `res.location("back")` and `res.redirect("back")` magic string
+  * deps: serve-static@1.16.2
+    * includes send@0.19.0
+  * deps: finalhandler@1.3.1
+  * deps: qs@6.13.0
+
+4.20.0 / 2024-09-10
+==========
+  * deps: serve-static@0.16.0
+    * Remove link renderization in html while redirecting
+  * deps: send@0.19.0
+    * Remove link renderization in html while redirecting
+  * deps: body-parser@0.6.0
+    * add `depth` option to customize the depth level in the parser
+    * IMPORTANT: The default `depth` level for parsing URL-encoded data is now `32` (previously was `Infinity`)
+  * Remove link renderization in html while using `res.redirect`
+  * deps: path-to-regexp@0.1.10
+    - Adds support for named matching groups in the routes using a regex
+    - Adds backtracking protection to parameters without regexes defined
+  * deps: encodeurl@~2.0.0
+    - Removes encoding of `\`, `|`, and `^` to align better with URL spec
+  * Deprecate passing `options.maxAge` and `options.expires` to `res.clearCookie`
+    - Will be ignored in v5, clearCookie will set a cookie with an expires in the past to instruct clients to delete the cookie
+
+4.19.2 / 2024-03-25
+==========
+
+  * Improved fix for open redirect allow list bypass
+
+4.19.1 / 2024-03-20
+==========
+
+  * Allow passing non-strings to res.location with new encoding handling checks
+
+4.19.0 / 2024-03-20
+==========
+
+  * Prevent open redirect allow list bypass due to encodeurl
+  * deps: cookie@0.6.0
+
+4.18.3 / 2024-02-29
+==========
+
+  * Fix routing requests without method
+  * deps: body-parser@1.20.2
+    - Fix strict json error message on Node.js 19+
+    - deps: content-type@~1.0.5
+    - deps: raw-body@2.5.2
+  * deps: cookie@0.6.0
+    - Add `partitioned` option
+
+4.18.2 / 2022-10-08
+===================
+
+  * Fix regression routing a large stack in a single route
+  * deps: body-parser@1.20.1
+    - deps: qs@6.11.0
+    - perf: remove unnecessary object clone
+  * deps: qs@6.11.0
+
+4.18.1 / 2022-04-29
+===================
+
+  * Fix hanging on large stack of sync routes
+
+4.18.0 / 2022-04-25
+===================
+
+  * Add "root" option to `res.download`
+  * Allow `options` without `filename` in `res.download`
+  * Deprecate string and non-integer arguments to `res.status`
+  * Fix behavior of `null`/`undefined` as `maxAge` in `res.cookie`
+  * Fix handling very large stacks of sync middleware
+  * Ignore `Object.prototype` values in settings through `app.set`/`app.get`
+  * Invoke `default` with same arguments as types in `res.format`
+  * Support proper 205 responses using `res.send`
+  * Use `http-errors` for `res.format` error
+  * deps: body-parser@1.20.0
+    - Fix error message for json parse whitespace in `strict`
+    - Fix internal error when inflated body exceeds limit
+    - Prevent loss of async hooks context
+    - Prevent hanging when request already read
+    - deps: depd@2.0.0
+    - deps: http-errors@2.0.0
+    - deps: on-finished@2.4.1
+    - deps: qs@6.10.3
+    - deps: raw-body@2.5.1
+  * deps: cookie@0.5.0
+    - Add `priority` option
+    - Fix `expires` option to reject invalid dates
+  * deps: depd@2.0.0
+    - Replace internal `eval` usage with `Function` constructor
+    - Use instance methods on `process` to check for listeners
+  * deps: finalhandler@1.2.0
+    - Remove set content headers that break response
+    - deps: on-finished@2.4.1
+    - deps: statuses@2.0.1
+  * deps: on-finished@2.4.1
+    - Prevent loss of async hooks context
+  * deps: qs@6.10.3
+  * deps: send@0.18.0
+    - Fix emitted 416 error missing headers property
+    - Limit the headers removed for 304 response
+    - deps: depd@2.0.0
+    - deps: destroy@1.2.0
+    - deps: http-errors@2.0.0
+    - deps: on-finished@2.4.1
+    - deps: statuses@2.0.1
+  * deps: serve-static@1.15.0
+    - deps: send@0.18.0
+  * deps: statuses@2.0.1
+    - Remove code 306
+    - Rename `425 Unordered Collection` to standard `425 Too Early`
+
+4.17.3 / 2022-02-16
+===================
+
+  * deps: accepts@~1.3.8
+    - deps: mime-types@~2.1.34
+    - deps: negotiator@0.6.3
+  * deps: body-parser@1.19.2
+    - deps: bytes@3.1.2
+    - deps: qs@6.9.7
+    - deps: raw-body@2.4.3
+  * deps: cookie@0.4.2
+  * deps: qs@6.9.7
+    * Fix handling of `__proto__` keys
+  * pref: remove unnecessary regexp for trust proxy
+
+4.17.2 / 2021-12-16
+===================
+
+  * Fix handling of `undefined` in `res.jsonp`
+  * Fix handling of `undefined` when `"json escape"` is enabled
+  * Fix incorrect middleware execution with unanchored `RegExp`s
+  * Fix `res.jsonp(obj, status)` deprecation message
+  * Fix typo in `res.is` JSDoc
+  * deps: body-parser@1.19.1
+    - deps: bytes@3.1.1
+    - deps: http-errors@1.8.1
+    - deps: qs@6.9.6
+    - deps: raw-body@2.4.2
+    - deps: safe-buffer@5.2.1
+    - deps: type-is@~1.6.18
+  * deps: content-disposition@0.5.4
+    - deps: safe-buffer@5.2.1
+  * deps: cookie@0.4.1
+    - Fix `maxAge` option to reject invalid values
+  * deps: proxy-addr@~2.0.7
+    - Use `req.socket` over deprecated `req.connection`
+    - deps: forwarded@0.2.0
+    - deps: ipaddr.js@1.9.1
+  * deps: qs@6.9.6
+  * deps: safe-buffer@5.2.1
+  * deps: send@0.17.2
+    - deps: http-errors@1.8.1
+    - deps: ms@2.1.3
+    - pref: ignore empty http tokens
+  * deps: serve-static@1.14.2
+    - deps: send@0.17.2
+  * deps: setprototypeof@1.2.0
+
+4.17.1 / 2019-05-25
+===================
+
+  * Revert "Improve error message for `null`/`undefined` to `res.status`"
+
+4.17.0 / 2019-05-16
+===================
+
+  * Add `express.raw` to parse bodies into `Buffer`
+  * Add `express.text` to parse bodies into string
+  * Improve error message for non-strings to `res.sendFile`
+  * Improve error message for `null`/`undefined` to `res.status`
+  * Support multiple hosts in `X-Forwarded-Host`
+  * deps: accepts@~1.3.7
+  * deps: body-parser@1.19.0
+    - Add encoding MIK
+    - Add petabyte (`pb`) support
+    - Fix parsing array brackets after index
+    - deps: bytes@3.1.0
+    - deps: http-errors@1.7.2
+    - deps: iconv-lite@0.4.24
+    - deps: qs@6.7.0
+    - deps: raw-body@2.4.0
+    - deps: type-is@~1.6.17
+  * deps: content-disposition@0.5.3
+  * deps: cookie@0.4.0
+    - Add `SameSite=None` support
+  * deps: finalhandler@~1.1.2
+    - Set stricter `Content-Security-Policy` header
+    - deps: parseurl@~1.3.3
+    - deps: statuses@~1.5.0
+  * deps: parseurl@~1.3.3
+  * deps: proxy-addr@~2.0.5
+    - deps: ipaddr.js@1.9.0
+  * deps: qs@6.7.0
+    - Fix parsing array brackets after index
+  * deps: range-parser@~1.2.1
+  * deps: send@0.17.1
+    - Set stricter CSP header in redirect & error responses
+    - deps: http-errors@~1.7.2
+    - deps: mime@1.6.0
+    - deps: ms@2.1.1
+    - deps: range-parser@~1.2.1
+    - deps: statuses@~1.5.0
+    - perf: remove redundant `path.normalize` call
+  * deps: serve-static@1.14.1
+    - Set stricter CSP header in redirect response
+    - deps: parseurl@~1.3.3
+    - deps: send@0.17.1
+  * deps: setprototypeof@1.1.1
+  * deps: statuses@~1.5.0
+    - Add `103 Early Hints`
+  * deps: type-is@~1.6.18
+    - deps: mime-types@~2.1.24
+    - perf: prevent internal `throw` on invalid type
+
+4.16.4 / 2018-10-10
+===================
+
+  * Fix issue where `"Request aborted"` may be logged in `res.sendfile`
+  * Fix JSDoc for `Router` constructor
+  * deps: body-parser@1.18.3
+    - Fix deprecation warnings on Node.js 10+
+    - Fix stack trace for strict json parse error
+    - deps: depd@~1.1.2
+    - deps: http-errors@~1.6.3
+    - deps: iconv-lite@0.4.23
+    - deps: qs@6.5.2
+    - deps: raw-body@2.3.3
+    - deps: type-is@~1.6.16
+  * deps: proxy-addr@~2.0.4
+    - deps: ipaddr.js@1.8.0
+  * deps: qs@6.5.2
+  * deps: safe-buffer@5.1.2
+
+4.16.3 / 2018-03-12
+===================
+
+  * deps: accepts@~1.3.5
+    - deps: mime-types@~2.1.18
+  * deps: depd@~1.1.2
+    - perf: remove argument reassignment
+  * deps: encodeurl@~1.0.2
+    - Fix encoding `%` as last character
+  * deps: finalhandler@1.1.1
+    - Fix 404 output for bad / missing pathnames
+    - deps: encodeurl@~1.0.2
+    - deps: statuses@~1.4.0
+  * deps: proxy-addr@~2.0.3
+    - deps: ipaddr.js@1.6.0
+  * deps: send@0.16.2
+    - Fix incorrect end tag in default error & redirects
+    - deps: depd@~1.1.2
+    - deps: encodeurl@~1.0.2
+    - deps: statuses@~1.4.0
+  * deps: serve-static@1.13.2
+    - Fix incorrect end tag in redirects
+    - deps: encodeurl@~1.0.2
+    - deps: send@0.16.2
+  * deps: statuses@~1.4.0
+  * deps: type-is@~1.6.16
+    - deps: mime-types@~2.1.18
+
+4.16.2 / 2017-10-09
+===================
+
+  * Fix `TypeError` in `res.send` when given `Buffer` and `ETag` header set
+  * perf: skip parsing of entire `X-Forwarded-Proto` header
+
+4.16.1 / 2017-09-29
+===================
+
+  * deps: send@0.16.1
+  * deps: serve-static@1.13.1
+    - Fix regression when `root` is incorrectly set to a file
+    - deps: send@0.16.1
+
+4.16.0 / 2017-09-28
+===================
+
+  * Add `"json escape"` setting for `res.json` and `res.jsonp`
+  * Add `express.json` and `express.urlencoded` to parse bodies
+  * Add `options` argument to `res.download`
+  * Improve error message when autoloading invalid view engine
+  * Improve error messages when non-function provided as middleware
+  * Skip `Buffer` encoding when not generating ETag for small response
+  * Use `safe-buffer` for improved Buffer API
+  * deps: accepts@~1.3.4
+    - deps: mime-types@~2.1.16
+  * deps: content-type@~1.0.4
+    - perf: remove argument reassignment
+    - perf: skip parameter parsing when no parameters
+  * deps: etag@~1.8.1
+    - perf: replace regular expression with substring
+  * deps: finalhandler@1.1.0
+    - Use `res.headersSent` when available
+  * deps: parseurl@~1.3.2
+    - perf: reduce overhead for full URLs
+    - perf: unroll the "fast-path" `RegExp`
+  * deps: proxy-addr@~2.0.2
+    - Fix trimming leading / trailing OWS in `X-Forwarded-For`
+    - deps: forwarded@~0.1.2
+    - deps: ipaddr.js@1.5.2
+    - perf: reduce overhead when no `X-Forwarded-For` header
+  * deps: qs@6.5.1
+    - Fix parsing & compacting very deep objects
+  * deps: send@0.16.0
+    - Add 70 new types for file extensions
+    - Add `immutable` option
+    - Fix missing `</html>` in default error & redirects
+    - Set charset as "UTF-8" for .js and .json
+    - Use instance methods on steam to check for listeners
+    - deps: mime@1.4.1
+    - perf: improve path validation speed
+  * deps: serve-static@1.13.0
+    - Add 70 new types for file extensions
+    - Add `immutable` option
+    - Set charset as "UTF-8" for .js and .json
+    - deps: send@0.16.0
+  * deps: setprototypeof@1.1.0
+  * deps: utils-merge@1.0.1
+  * deps: vary@~1.1.2
+    - perf: improve header token parsing speed
+  * perf: re-use options object when generating ETags
+  * perf: remove dead `.charset` set in `res.jsonp`
+
+4.15.5 / 2017-09-24
+===================
+
+  * deps: debug@2.6.9
+  * deps: finalhandler@~1.0.6
+    - deps: debug@2.6.9
+    - deps: parseurl@~1.3.2
+  * deps: fresh@0.5.2
+    - Fix handling of modified headers with invalid dates
+    - perf: improve ETag match loop
+    - perf: improve `If-None-Match` token parsing
+  * deps: send@0.15.6
+    - Fix handling of modified headers with invalid dates
+    - deps: debug@2.6.9
+    - deps: etag@~1.8.1
+    - deps: fresh@0.5.2
+    - perf: improve `If-Match` token parsing
+  * deps: serve-static@1.12.6
+    - deps: parseurl@~1.3.2
+    - deps: send@0.15.6
+    - perf: improve slash collapsing
+
+4.15.4 / 2017-08-06
+===================
+
+  * deps: debug@2.6.8
+  * deps: depd@~1.1.1
+    - Remove unnecessary `Buffer` loading
+  * deps: finalhandler@~1.0.4
+    - deps: debug@2.6.8
+  * deps: proxy-addr@~1.1.5
+    - Fix array argument being altered
+    - deps: ipaddr.js@1.4.0
+  * deps: qs@6.5.0
+  * deps: send@0.15.4
+    - deps: debug@2.6.8
+    - deps: depd@~1.1.1
+    - deps: http-errors@~1.6.2
+  * deps: serve-static@1.12.4
+    - deps: send@0.15.4
+
+4.15.3 / 2017-05-16
+===================
+
+  * Fix error when `res.set` cannot add charset to `Content-Type`
+  * deps: debug@2.6.7
+    - Fix `DEBUG_MAX_ARRAY_LENGTH`
+    - deps: ms@2.0.0
+  * deps: finalhandler@~1.0.3
+    - Fix missing `</html>` in HTML document
+    - deps: debug@2.6.7
+  * deps: proxy-addr@~1.1.4
+    - deps: ipaddr.js@1.3.0
+  * deps: send@0.15.3
+    - deps: debug@2.6.7
+    - deps: ms@2.0.0
+  * deps: serve-static@1.12.3
+    - deps: send@0.15.3
+  * deps: type-is@~1.6.15
+    - deps: mime-types@~2.1.15
+  * deps: vary@~1.1.1
+    - perf: hoist regular expression
+
+4.15.2 / 2017-03-06
+===================
+
+  * deps: qs@6.4.0
+    - Fix regression parsing keys starting with `[`
+
+4.15.1 / 2017-03-05
+===================
+
+  * deps: send@0.15.1
+    - Fix issue when `Date.parse` does not return `NaN` on invalid date
+    - Fix strict violation in broken environments
+  * deps: serve-static@1.12.1
+    - Fix issue when `Date.parse` does not return `NaN` on invalid date
+    - deps: send@0.15.1
+
+4.15.0 / 2017-03-01
+===================
+
+  * Add debug message when loading view engine
+  * Add `next("router")` to exit from router
+  * Fix case where `router.use` skipped requests routes did not
+  * Remove usage of `res._headers` private field
+    - Improves compatibility with Node.js 8 nightly
+  * Skip routing when `req.url` is not set
+  * Use `%o` in path debug to tell types apart
+  * Use `Object.create` to setup request & response prototypes
+  * Use `setprototypeof` module to replace `__proto__` setting
+  * Use `statuses` instead of `http` module for status messages
+  * deps: debug@2.6.1
+    - Allow colors in workers
+    - Deprecated `DEBUG_FD` environment variable set to `3` or higher
+    - Fix error when running under React Native
+    - Use same color for same namespace
+    - deps: ms@0.7.2
+  * deps: etag@~1.8.0
+    - Use SHA1 instead of MD5 for ETag hashing
+    - Works with FIPS 140-2 OpenSSL configuration
+  * deps: finalhandler@~1.0.0
+    - Fix exception when `err` cannot be converted to a string
+    - Fully URL-encode the pathname in the 404
+    - Only include the pathname in the 404 message
+    - Send complete HTML document
+    - Set `Content-Security-Policy: default-src 'self'` header
+    - deps: debug@2.6.1
+  * deps: fresh@0.5.0
+    - Fix false detection of `no-cache` request directive
+    - Fix incorrect result when `If-None-Match` has both `*` and ETags
+    - Fix weak `ETag` matching to match spec
+    - perf: delay reading header values until needed
+    - perf: enable strict mode
+    - perf: hoist regular expressions
+    - perf: remove duplicate conditional
+    - perf: remove unnecessary boolean coercions
+    - perf: skip checking modified time if ETag check failed
+    - perf: skip parsing `If-None-Match` when no `ETag` header
+    - perf: use `Date.parse` instead of `new Date`
+  * deps: qs@6.3.1
+    - Fix array parsing from skipping empty values
+    - Fix compacting nested arrays
+  * deps: send@0.15.0
+    - Fix false detection of `no-cache` request directive
+    - Fix incorrect result when `If-None-Match` has both `*` and ETags
+    - Fix weak `ETag` matching to match spec
+    - Remove usage of `res._headers` private field
+    - Support `If-Match` and `If-Unmodified-Since` headers
+    - Use `res.getHeaderNames()` when available
+    - Use `res.headersSent` when available
+    - deps: debug@2.6.1
+    - deps: etag@~1.8.0
+    - deps: fresh@0.5.0
+    - deps: http-errors@~1.6.1
+  * deps: serve-static@1.12.0
+    - Fix false detection of `no-cache` request directive
+    - Fix incorrect result when `If-None-Match` has both `*` and ETags
+    - Fix weak `ETag` matching to match spec
+    - Remove usage of `res._headers` private field
+    - Send complete HTML document in redirect response
+    - Set default CSP header in redirect response
+    - Support `If-Match` and `If-Unmodified-Since` headers
+    - Use `res.getHeaderNames()` when available
+    - Use `res.headersSent` when available
+    - deps: send@0.15.0
+  * perf: add fast match path for `*` route
+  * perf: improve `req.ips` performance
+
+4.14.1 / 2017-01-28
+===================
+
+  * deps: content-disposition@0.5.2
+  * deps: finalhandler@0.5.1
+    - Fix exception when `err.headers` is not an object
+    - deps: statuses@~1.3.1
+    - perf: hoist regular expressions
+    - perf: remove duplicate validation path
+  * deps: proxy-addr@~1.1.3
+    - deps: ipaddr.js@1.2.0
+  * deps: send@0.14.2
+    - deps: http-errors@~1.5.1
+    - deps: ms@0.7.2
+    - deps: statuses@~1.3.1
+  * deps: serve-static@~1.11.2
+    - deps: send@0.14.2
+  * deps: type-is@~1.6.14
+    - deps: mime-types@~2.1.13
+
+4.14.0 / 2016-06-16
+===================
+
+  * Add `acceptRanges` option to `res.sendFile`/`res.sendfile`
+  * Add `cacheControl` option to `res.sendFile`/`res.sendfile`
+  * Add `options` argument to `req.range`
+    - Includes the `combine` option
+  * Encode URL in `res.location`/`res.redirect` if not already encoded
+  * Fix some redirect handling in `res.sendFile`/`res.sendfile`
+  * Fix Windows absolute path check using forward slashes
+  * Improve error with invalid arguments to `req.get()`
+  * Improve performance for `res.json`/`res.jsonp` in most cases
+  * Improve `Range` header handling in `res.sendFile`/`res.sendfile`
+  * deps: accepts@~1.3.3
+    - Fix including type extensions in parameters in `Accept` parsing
+    - Fix parsing `Accept` parameters with quoted equals
+    - Fix parsing `Accept` parameters with quoted semicolons
+    - Many performance improvements
+    - deps: mime-types@~2.1.11
+    - deps: negotiator@0.6.1
+  * deps: content-type@~1.0.2
+    - perf: enable strict mode
+  * deps: cookie@0.3.1
+    - Add `sameSite` option
+    - Fix cookie `Max-Age` to never be a floating point number
+    - Improve error message when `encode` is not a function
+    - Improve error message when `expires` is not a `Date`
+    - Throw better error for invalid argument to parse
+    - Throw on invalid values provided to `serialize`
+    - perf: enable strict mode
+    - perf: hoist regular expression
+    - perf: use for loop in parse
+    - perf: use string concatenation for serialization
+  * deps: finalhandler@0.5.0
+    - Change invalid or non-numeric status code to 500
+    - Overwrite status message to match set status code
+    - Prefer `err.statusCode` if `err.status` is invalid
+    - Set response headers from `err.headers` object
+    - Use `statuses` instead of `http` module for status messages
+  * deps: proxy-addr@~1.1.2
+    - Fix accepting various invalid netmasks
+    - Fix IPv6-mapped IPv4 validation edge cases
+    - IPv4 netmasks must be contiguous
+    - IPv6 addresses cannot be used as a netmask
+    - deps: ipaddr.js@1.1.1
+  * deps: qs@6.2.0
+    - Add `decoder` option in `parse` function
+  * deps: range-parser@~1.2.0
+    - Add `combine` option to combine overlapping ranges
+    - Fix incorrectly returning -1 when there is at least one valid range
+    - perf: remove internal function
+  * deps: send@0.14.1
+    - Add `acceptRanges` option
+    - Add `cacheControl` option
+    - Attempt to combine multiple ranges into single range
+    - Correctly inherit from `Stream` class
+    - Fix `Content-Range` header in 416 responses when using `start`/`end` options
+    - Fix `Content-Range` header missing from default 416 responses
+    - Fix redirect error when `path` contains raw non-URL characters
+    - Fix redirect when `path` starts with multiple forward slashes
+    - Ignore non-byte `Range` headers
+    - deps: http-errors@~1.5.0
+    - deps: range-parser@~1.2.0
+    - deps: statuses@~1.3.0
+    - perf: remove argument reassignment
+  * deps: serve-static@~1.11.1
+    - Add `acceptRanges` option
+    - Add `cacheControl` option
+    - Attempt to combine multiple ranges into single range
+    - Fix redirect error when `req.url` contains raw non-URL characters
+    - Ignore non-byte `Range` headers
+    - Use status code 301 for redirects
+    - deps: send@0.14.1
+  * deps: type-is@~1.6.13
+    - Fix type error when given invalid type to match against
+    - deps: mime-types@~2.1.11
+  * deps: vary@~1.1.0
+    - Only accept valid field names in the `field` argument
+  * perf: use strict equality when possible
+
+4.13.4 / 2016-01-21
+===================
+
+  * deps: content-disposition@0.5.1
+    - perf: enable strict mode
+  * deps: cookie@0.1.5
+    - Throw on invalid values provided to `serialize`
+  * deps: depd@~1.1.0
+    - Support web browser loading
+    - perf: enable strict mode
+  * deps: escape-html@~1.0.3
+    - perf: enable strict mode
+    - perf: optimize string replacement
+    - perf: use faster string coercion
+  * deps: finalhandler@0.4.1
+    - deps: escape-html@~1.0.3
+  * deps: merge-descriptors@1.0.1
+    - perf: enable strict mode
+  * deps: methods@~1.1.2
+    - perf: enable strict mode
+  * deps: parseurl@~1.3.1
+    - perf: enable strict mode
+  * deps: proxy-addr@~1.0.10
+    - deps: ipaddr.js@1.0.5
+    - perf: enable strict mode
+  * deps: range-parser@~1.0.3
+    - perf: enable strict mode
+  * deps: send@0.13.1
+    - deps: depd@~1.1.0
+    - deps: destroy@~1.0.4
+    - deps: escape-html@~1.0.3
+    - deps: range-parser@~1.0.3
+  * deps: serve-static@~1.10.2
+    - deps: escape-html@~1.0.3
+    - deps: parseurl@~1.3.0
+    - deps: send@0.13.1
+
+4.13.3 / 2015-08-02
+===================
+
+  * Fix infinite loop condition using `mergeParams: true`
+  * Fix inner numeric indices incorrectly altering parent `req.params`
+
+4.13.2 / 2015-07-31
+===================
+
+  * deps: accepts@~1.2.12
+    - deps: mime-types@~2.1.4
+  * deps: array-flatten@1.1.1
+    - perf: enable strict mode
+  * deps: path-to-regexp@0.1.7
+    - Fix regression with escaped round brackets and matching groups
+  * deps: type-is@~1.6.6
+    - deps: mime-types@~2.1.4
+
+4.13.1 / 2015-07-05
+===================
+
+  * deps: accepts@~1.2.10
+    - deps: mime-types@~2.1.2
+  * deps: qs@4.0.0
+    - Fix dropping parameters like `hasOwnProperty`
+    - Fix various parsing edge cases
+  * deps: type-is@~1.6.4
+    - deps: mime-types@~2.1.2
+    - perf: enable strict mode
+    - perf: remove argument reassignment
+
+4.13.0 / 2015-06-20
+===================
+
+  * Add settings to debug output
+  * Fix `res.format` error when only `default` provided
+  * Fix issue where `next('route')` in `app.param` would incorrectly skip values
+  * Fix hiding platform issues with `decodeURIComponent`
+    - Only `URIError`s are a 400
+  * Fix using `*` before params in routes
+  * Fix using capture groups before params in routes
+  * Simplify `res.cookie` to call `res.append`
+  * Use `array-flatten` module for flattening arrays
+  * deps: accepts@~1.2.9
+    - deps: mime-types@~2.1.1
+    - perf: avoid argument reassignment & argument slice
+    - perf: avoid negotiator recursive construction
+    - perf: enable strict mode
+    - perf: remove unnecessary bitwise operator
+  * deps: cookie@0.1.3
+    - perf: deduce the scope of try-catch deopt
+    - perf: remove argument reassignments
+  * deps: escape-html@1.0.2
+  * deps: etag@~1.7.0
+    - Always include entity length in ETags for hash length extensions
+    - Generate non-Stats ETags using MD5 only (no longer CRC32)
+    - Improve stat performance by removing hashing
+    - Improve support for JXcore
+    - Remove base64 padding in ETags to shorten
+    - Support "fake" stats objects in environments without fs
+    - Use MD5 instead of MD4 in weak ETags over 1KB
+  * deps: finalhandler@0.4.0
+    - Fix a false-positive when unpiping in Node.js 0.8
+    - Support `statusCode` property on `Error` objects
+    - Use `unpipe` module for unpiping requests
+    - deps: escape-html@1.0.2
+    - deps: on-finished@~2.3.0
+    - perf: enable strict mode
+    - perf: remove argument reassignment
+  * deps: fresh@0.3.0
+    - Add weak `ETag` matching support
+  * deps: on-finished@~2.3.0
+    - Add defined behavior for HTTP `CONNECT` requests
+    - Add defined behavior for HTTP `Upgrade` requests
+    - deps: ee-first@1.1.1
+  * deps: path-to-regexp@0.1.6
+  * deps: send@0.13.0
+    - Allow Node.js HTTP server to set `Date` response header
+    - Fix incorrectly removing `Content-Location` on 304 response
+    - Improve the default redirect response headers
+    - Send appropriate headers on default error response
+    - Use `http-errors` for standard emitted errors
+    - Use `statuses` instead of `http` module for status messages
+    - deps: escape-html@1.0.2
+    - deps: etag@~1.7.0
+    - deps: fresh@0.3.0
+    - deps: on-finished@~2.3.0
+    - perf: enable strict mode
+    - perf: remove unnecessary array allocations
+  * deps: serve-static@~1.10.0
+    - Add `fallthrough` option
+    - Fix reading options from options prototype
+    - Improve the default redirect response headers
+    - Malformed URLs now `next()` instead of 400
+    - deps: escape-html@1.0.2
+    - deps: send@0.13.0
+    - perf: enable strict mode
+    - perf: remove argument reassignment
+  * deps: type-is@~1.6.3
+    - deps: mime-types@~2.1.1
+    - perf: reduce try block size
+    - perf: remove bitwise operations
+  * perf: enable strict mode
+  * perf: isolate `app.render` try block
+  * perf: remove argument reassignments in application
+  * perf: remove argument reassignments in request prototype
+  * perf: remove argument reassignments in response prototype
+  * perf: remove argument reassignments in routing
+  * perf: remove argument reassignments in `View`
+  * perf: skip attempting to decode zero length string
+  * perf: use saved reference to `http.STATUS_CODES`
+
+4.12.4 / 2015-05-17
+===================
+
+  * deps: accepts@~1.2.7
+    - deps: mime-types@~2.0.11
+    - deps: negotiator@0.5.3
+  * deps: debug@~2.2.0
+    - deps: ms@0.7.1
+  * deps: depd@~1.0.1
+  * deps: etag@~1.6.0
+    - Improve support for JXcore
+    - Support "fake" stats objects in environments without `fs`
+  * deps: finalhandler@0.3.6
+    - deps: debug@~2.2.0
+    - deps: on-finished@~2.2.1
+  * deps: on-finished@~2.2.1
+    - Fix `isFinished(req)` when data buffered
+  * deps: proxy-addr@~1.0.8
+    - deps: ipaddr.js@1.0.1
+  * deps: qs@2.4.2
+   - Fix allowing parameters like `constructor`
+  * deps: send@0.12.3
+    - deps: debug@~2.2.0
+    - deps: depd@~1.0.1
+    - deps: etag@~1.6.0
+    - deps: ms@0.7.1
+    - deps: on-finished@~2.2.1
+  * deps: serve-static@~1.9.3
+    - deps: send@0.12.3
+  * deps: type-is@~1.6.2
+    - deps: mime-types@~2.0.11
+
+4.12.3 / 2015-03-17
+===================
+
+  * deps: accepts@~1.2.5
+    - deps: mime-types@~2.0.10
+  * deps: debug@~2.1.3
+    - Fix high intensity foreground color for bold
+    - deps: ms@0.7.0
+  * deps: finalhandler@0.3.4
+    - deps: debug@~2.1.3
+  * deps: proxy-addr@~1.0.7
+    - deps: ipaddr.js@0.1.9
+  * deps: qs@2.4.1
+    - Fix error when parameter `hasOwnProperty` is present
+  * deps: send@0.12.2
+    - Throw errors early for invalid `extensions` or `index` options
+    - deps: debug@~2.1.3
+  * deps: serve-static@~1.9.2
+    - deps: send@0.12.2
+  * deps: type-is@~1.6.1
+    - deps: mime-types@~2.0.10
+
+4.12.2 / 2015-03-02
+===================
+
+  * Fix regression where `"Request aborted"` is logged using `res.sendFile`
+
+4.12.1 / 2015-03-01
+===================
+
+  * Fix constructing application with non-configurable prototype properties
+  * Fix `ECONNRESET` errors from `res.sendFile` usage
+  * Fix `req.host` when using "trust proxy" hops count
+  * Fix `req.protocol`/`req.secure` when using "trust proxy" hops count
+  * Fix wrong `code` on aborted connections from `res.sendFile`
+  * deps: merge-descriptors@1.0.0
+
+4.12.0 / 2015-02-23
+===================
+
+  * Fix `"trust proxy"` setting to inherit when app is mounted
+  * Generate `ETag`s for all request responses
+    - No longer restricted to only responses for `GET` and `HEAD` requests
+  * Use `content-type` to parse `Content-Type` headers
+  * deps: accepts@~1.2.4
+    - Fix preference sorting to be stable for long acceptable lists
+    - deps: mime-types@~2.0.9
+    - deps: negotiator@0.5.1
+  * deps: cookie-signature@1.0.6
+  * deps: send@0.12.1
+    - Always read the stat size from the file
+    - Fix mutating passed-in `options`
+    - deps: mime@1.3.4
+  * deps: serve-static@~1.9.1
+    - deps: send@0.12.1
+  * deps: type-is@~1.6.0
+    - fix argument reassignment
+    - fix false-positives in `hasBody` `Transfer-Encoding` check
+    - support wildcard for both type and subtype (`*/*`)
+    - deps: mime-types@~2.0.9
+
+4.11.2 / 2015-02-01
+===================
+
+  * Fix `res.redirect` double-calling `res.end` for `HEAD` requests
+  * deps: accepts@~1.2.3
+    - deps: mime-types@~2.0.8
+  * deps: proxy-addr@~1.0.6
+    - deps: ipaddr.js@0.1.8
+  * deps: type-is@~1.5.6
+    - deps: mime-types@~2.0.8
+
+4.11.1 / 2015-01-20
+===================
+
+  * deps: send@0.11.1
+    - Fix root path disclosure
+  * deps: serve-static@~1.8.1
+    - Fix redirect loop in Node.js 0.11.14
+    - Fix root path disclosure
+    - deps: send@0.11.1
+
+4.11.0 / 2015-01-13
+===================
+
+  * Add `res.append(field, val)` to append headers
+  * Deprecate leading `:` in `name` for `app.param(name, fn)`
+  * Deprecate `req.param()` -- use `req.params`, `req.body`, or `req.query` instead
+  * Deprecate `app.param(fn)`
+  * Fix `OPTIONS` responses to include the `HEAD` method properly
+  * Fix `res.sendFile` not always detecting aborted connection
+  * Match routes iteratively to prevent stack overflows
+  * deps: accepts@~1.2.2
+    - deps: mime-types@~2.0.7
+    - deps: negotiator@0.5.0
+  * deps: send@0.11.0
+    - deps: debug@~2.1.1
+    - deps: etag@~1.5.1
+    - deps: ms@0.7.0
+    - deps: on-finished@~2.2.0
+  * deps: serve-static@~1.8.0
+    - deps: send@0.11.0
+
+4.10.8 / 2015-01-13
+===================
+
+  * Fix crash from error within `OPTIONS` response handler
+  * deps: proxy-addr@~1.0.5
+    - deps: ipaddr.js@0.1.6
+
+4.10.7 / 2015-01-04
+===================
+
+  * Fix `Allow` header for `OPTIONS` to not contain duplicate methods
+  * Fix incorrect "Request aborted" for `res.sendFile` when `HEAD` or 304
+  * deps: debug@~2.1.1
+  * deps: finalhandler@0.3.3
+    - deps: debug@~2.1.1
+    - deps: on-finished@~2.2.0
+  * deps: methods@~1.1.1
+  * deps: on-finished@~2.2.0
+  * deps: serve-static@~1.7.2
+    - Fix potential open redirect when mounted at root
+  * deps: type-is@~1.5.5
+    - deps: mime-types@~2.0.7
+
+4.10.6 / 2014-12-12
+===================
+
+  * Fix exception in `req.fresh`/`req.stale` without response headers
+
+4.10.5 / 2014-12-10
+===================
+
+  * Fix `res.send` double-calling `res.end` for `HEAD` requests
+  * deps: accepts@~1.1.4
+    - deps: mime-types@~2.0.4
+  * deps: type-is@~1.5.4
+    - deps: mime-types@~2.0.4
+
+4.10.4 / 2014-11-24
+===================
+
+  * Fix `res.sendfile` logging standard write errors
+
+4.10.3 / 2014-11-23
+===================
+
+  * Fix `res.sendFile` logging standard write errors
+  * deps: etag@~1.5.1
+  * deps: proxy-addr@~1.0.4
+    - deps: ipaddr.js@0.1.5
+  * deps: qs@2.3.3
+    - Fix `arrayLimit` behavior
+
+4.10.2 / 2014-11-09
+===================
+
+  * Correctly invoke async router callback asynchronously
+  * deps: accepts@~1.1.3
+    - deps: mime-types@~2.0.3
+  * deps: type-is@~1.5.3
+    - deps: mime-types@~2.0.3
+
+4.10.1 / 2014-10-28
+===================
+
+  * Fix handling of URLs containing `://` in the path
+  * deps: qs@2.3.2
+    - Fix parsing of mixed objects and values
+
+4.10.0 / 2014-10-23
+===================
+
+  * Add support for `app.set('views', array)`
+    - Views are looked up in sequence in array of directories
+  * Fix `res.send(status)` to mention `res.sendStatus(status)`
+  * Fix handling of invalid empty URLs
+  * Use `content-disposition` module for `res.attachment`/`res.download`
+    - Sends standards-compliant `Content-Disposition` header
+    - Full Unicode support
+  * Use `path.resolve` in view lookup
+  * deps: debug@~2.1.0
+    - Implement `DEBUG_FD` env variable support
+  * deps: depd@~1.0.0
+  * deps: etag@~1.5.0
+    - Improve string performance
+    - Slightly improve speed for weak ETags over 1KB
+  * deps: finalhandler@0.3.2
+    - Terminate in progress response only on error
+    - Use `on-finished` to determine request status
+    - deps: debug@~2.1.0
+    - deps: on-finished@~2.1.1
+  * deps: on-finished@~2.1.1
+    - Fix handling of pipelined requests
+  * deps: qs@2.3.0
+    - Fix parsing of mixed implicit and explicit arrays
+  * deps: send@0.10.1
+    - deps: debug@~2.1.0
+    - deps: depd@~1.0.0
+    - deps: etag@~1.5.0
+    - deps: on-finished@~2.1.1
+  * deps: serve-static@~1.7.1
+    - deps: send@0.10.1
+
+4.9.8 / 2014-10-17
+==================
+
+  * Fix `res.redirect` body when redirect status specified
+  * deps: accepts@~1.1.2
+    - Fix error when media type has invalid parameter
+    - deps: negotiator@0.4.9
+
+4.9.7 / 2014-10-10
+==================
+
+  * Fix using same param name in array of paths
+
+4.9.6 / 2014-10-08
+==================
+
+  * deps: accepts@~1.1.1
+    - deps: mime-types@~2.0.2
+    - deps: negotiator@0.4.8
+  * deps: serve-static@~1.6.4
+    - Fix redirect loop when index file serving disabled
+  * deps: type-is@~1.5.2
+    - deps: mime-types@~2.0.2
+
+4.9.5 / 2014-09-24
+==================
+
+  * deps: etag@~1.4.0
+  * deps: proxy-addr@~1.0.3
+    - Use `forwarded` npm module
+  * deps: send@0.9.3
+    - deps: etag@~1.4.0
+  * deps: serve-static@~1.6.3
+    - deps: send@0.9.3
+
+4.9.4 / 2014-09-19
+==================
+
+  * deps: qs@2.2.4
+    - Fix issue with object keys starting with numbers truncated
+
+4.9.3 / 2014-09-18
+==================
+
+  * deps: proxy-addr@~1.0.2
+    - Fix a global leak when multiple subnets are trusted
+    - deps: ipaddr.js@0.1.3
+
+4.9.2 / 2014-09-17
+==================
+
+  * Fix regression for empty string `path` in `app.use`
+  * Fix `router.use` to accept array of middleware without path
+  * Improve error message for bad `app.use` arguments
+
+4.9.1 / 2014-09-16
+==================
+
+  * Fix `app.use` to accept array of middleware without path
+  * deps: depd@0.4.5
+  * deps: etag@~1.3.1
+  * deps: send@0.9.2
+    - deps: depd@0.4.5
+    - deps: etag@~1.3.1
+    - deps: range-parser@~1.0.2
+  * deps: serve-static@~1.6.2
+    - deps: send@0.9.2
+
+4.9.0 / 2014-09-08
+==================
+
+  * Add `res.sendStatus`
+  * Invoke callback for sendfile when client aborts
+    - Applies to `res.sendFile`, `res.sendfile`, and `res.download`
+    - `err` will be populated with request aborted error
+  * Support IP address host in `req.subdomains`
+  * Use `etag` to generate `ETag` headers
+  * deps: accepts@~1.1.0
+    - update `mime-types`
+  * deps: cookie-signature@1.0.5
+  * deps: debug@~2.0.0
+  * deps: finalhandler@0.2.0
+    - Set `X-Content-Type-Options: nosniff` header
+    - deps: debug@~2.0.0
+  * deps: fresh@0.2.4
+  * deps: media-typer@0.3.0
+    - Throw error when parameter format invalid on parse
+  * deps: qs@2.2.3
+    - Fix issue where first empty value in array is discarded
+  * deps: range-parser@~1.0.2
+  * deps: send@0.9.1
+    - Add `lastModified` option
+    - Use `etag` to generate `ETag` header
+    - deps: debug@~2.0.0
+    - deps: fresh@0.2.4
+  * deps: serve-static@~1.6.1
+    - Add `lastModified` option
+    - deps: send@0.9.1
+  * deps: type-is@~1.5.1
+    - fix `hasbody` to be true for `content-length: 0`
+    - deps: media-typer@0.3.0
+    - deps: mime-types@~2.0.1
+  * deps: vary@~1.0.0
+    - Accept valid `Vary` header string as `field`
+
+4.8.8 / 2014-09-04
+==================
+
+  * deps: send@0.8.5
+    - Fix a path traversal issue when using `root`
+    - Fix malicious path detection for empty string path
+  * deps: serve-static@~1.5.4
+    - deps: send@0.8.5
+
+4.8.7 / 2014-08-29
+==================
+
+  * deps: qs@2.2.2
+    - Remove unnecessary cloning
+
+4.8.6 / 2014-08-27
+==================
+
+  * deps: qs@2.2.0
+    - Array parsing fix
+    - Performance improvements
+
+4.8.5 / 2014-08-18
+==================
+
+  * deps: send@0.8.3
+    - deps: destroy@1.0.3
+    - deps: on-finished@2.1.0
+  * deps: serve-static@~1.5.3
+    - deps: send@0.8.3
+
+4.8.4 / 2014-08-14
+==================
+
+  * deps: qs@1.2.2
+  * deps: send@0.8.2
+    - Work around `fd` leak in Node.js 0.10 for `fs.ReadStream`
+  * deps: serve-static@~1.5.2
+    - deps: send@0.8.2
+
+4.8.3 / 2014-08-10
+==================
+
+  * deps: parseurl@~1.3.0
+  * deps: qs@1.2.1
+  * deps: serve-static@~1.5.1
+    - Fix parsing of weird `req.originalUrl` values
+    - deps: parseurl@~1.3.0
+    - deps: utils-merge@1.0.0
+
+4.8.2 / 2014-08-07
+==================
+
+  * deps: qs@1.2.0
+    - Fix parsing array of objects
+
+4.8.1 / 2014-08-06
+==================
+
+  * fix incorrect deprecation warnings on `res.download`
+  * deps: qs@1.1.0
+    - Accept urlencoded square brackets
+    - Accept empty values in implicit array notation
+
+4.8.0 / 2014-08-05
+==================
+
+  * add `res.sendFile`
+    - accepts a file system path instead of a URL
+    - requires an absolute path or `root` option specified
+  * deprecate `res.sendfile` -- use `res.sendFile` instead
+  * support mounted app as any argument to `app.use()`
+  * deps: qs@1.0.2
+    - Complete rewrite
+    - Limits array length to 20
+    - Limits object depth to 5
+    - Limits parameters to 1,000
+  * deps: send@0.8.1
+    - Add `extensions` option
+  * deps: serve-static@~1.5.0
+    - Add `extensions` option
+    - deps: send@0.8.1
+
+4.7.4 / 2014-08-04
+==================
+
+  * fix `res.sendfile` regression for serving directory index files
+  * deps: send@0.7.4
+    - Fix incorrect 403 on Windows and Node.js 0.11
+    - Fix serving index files without root dir
+  * deps: serve-static@~1.4.4
+    - deps: send@0.7.4
+
+4.7.3 / 2014-08-04
+==================
+
+  * deps: send@0.7.3
+    - Fix incorrect 403 on Windows and Node.js 0.11
+  * deps: serve-static@~1.4.3
+    - Fix incorrect 403 on Windows and Node.js 0.11
+    - deps: send@0.7.3
+
+4.7.2 / 2014-07-27
+==================
+
+  * deps: depd@0.4.4
+    - Work-around v8 generating empty stack traces
+  * deps: send@0.7.2
+    - deps: depd@0.4.4
+  * deps: serve-static@~1.4.2
+
+4.7.1 / 2014-07-26
+==================
+
+  * deps: depd@0.4.3
+    - Fix exception when global `Error.stackTraceLimit` is too low
+  * deps: send@0.7.1
+    - deps: depd@0.4.3
+  * deps: serve-static@~1.4.1
+
+4.7.0 / 2014-07-25
+==================
+
+  * fix `req.protocol` for proxy-direct connections
+  * configurable query parser with `app.set('query parser', parser)`
+    - `app.set('query parser', 'extended')` parse with "qs" module
+    - `app.set('query parser', 'simple')` parse with "querystring" core module
+    - `app.set('query parser', false)` disable query string parsing
+    - `app.set('query parser', true)` enable simple parsing
+  * deprecate `res.json(status, obj)` -- use `res.status(status).json(obj)` instead
+  * deprecate `res.jsonp(status, obj)` -- use `res.status(status).jsonp(obj)` instead
+  * deprecate `res.send(status, body)` -- use `res.status(status).send(body)` instead
+  * deps: debug@1.0.4
+  * deps: depd@0.4.2
+    - Add `TRACE_DEPRECATION` environment variable
+    - Remove non-standard grey color from color output
+    - Support `--no-deprecation` argument
+    - Support `--trace-deprecation` argument
+  * deps: finalhandler@0.1.0
+    - Respond after request fully read
+    - deps: debug@1.0.4
+  * deps: parseurl@~1.2.0
+    - Cache URLs based on original value
+    - Remove no-longer-needed URL mis-parse work-around
+    - Simplify the "fast-path" `RegExp`
+  * deps: send@0.7.0
+    - Add `dotfiles` option
+    - Cap `maxAge` value to 1 year
+    - deps: debug@1.0.4
+    - deps: depd@0.4.2
+  * deps: serve-static@~1.4.0
+    - deps: parseurl@~1.2.0
+    - deps: send@0.7.0
+  * perf: prevent multiple `Buffer` creation in `res.send`
+
+4.6.1 / 2014-07-12
+==================
+
+  * fix `subapp.mountpath` regression for `app.use(subapp)`
+
+4.6.0 / 2014-07-11
+==================
+
+  * accept multiple callbacks to `app.use()`
+  * add explicit "Rosetta Flash JSONP abuse" protection
+    - previous versions are not vulnerable; this is just explicit protection
+  * catch errors in multiple `req.param(name, fn)` handlers
+  * deprecate `res.redirect(url, status)` -- use `res.redirect(status, url)` instead
+  * fix `res.send(status, num)` to send `num` as json (not error)
+  * remove unnecessary escaping when `res.jsonp` returns JSON response
+  * support non-string `path` in `app.use(path, fn)`
+    - supports array of paths
+    - supports `RegExp`
+  * router: fix optimization on router exit
+  * router: refactor location of `try` blocks
+  * router: speed up standard `app.use(fn)`
+  * deps: debug@1.0.3
+    - Add support for multiple wildcards in namespaces
+  * deps: finalhandler@0.0.3
+    - deps: debug@1.0.3
+  * deps: methods@1.1.0
+    - add `CONNECT`
+  * deps: parseurl@~1.1.3
+    - faster parsing of href-only URLs
+  * deps: path-to-regexp@0.1.3
+  * deps: send@0.6.0
+    - deps: debug@1.0.3
+  * deps: serve-static@~1.3.2
+    - deps: parseurl@~1.1.3
+    - deps: send@0.6.0
+  * perf: fix arguments reassign deopt in some `res` methods
+
+4.5.1 / 2014-07-06
+==================
+
+ * fix routing regression when altering `req.method`
+
+4.5.0 / 2014-07-04
+==================
+
+ * add deprecation message to non-plural `req.accepts*`
+ * add deprecation message to `res.send(body, status)`
+ * add deprecation message to `res.vary()`
+ * add `headers` option to `res.sendfile`
+   - use to set headers on successful file transfer
+ * add `mergeParams` option to `Router`
+   - merges `req.params` from parent routes
+ * add `req.hostname` -- correct name for what `req.host` returns
+ * deprecate things with `depd` module
+ * deprecate `req.host` -- use `req.hostname` instead
+ * fix behavior when handling request without routes
+ * fix handling when `route.all` is only route
+ * invoke `router.param()` only when route matches
+ * restore `req.params` after invoking router
+ * use `finalhandler` for final response handling
+ * use `media-typer` to alter content-type charset
+ * deps: accepts@~1.0.7
+ * deps: send@0.5.0
+   - Accept string for `maxage` (converted by `ms`)
+   - Include link in default redirect response
+ * deps: serve-static@~1.3.0
+   - Accept string for `maxAge` (converted by `ms`)
+   - Add `setHeaders` option
+   - Include HTML link in redirect response
+   - deps: send@0.5.0
+ * deps: type-is@~1.3.2
+
+4.4.5 / 2014-06-26
+==================
+
+ * deps: cookie-signature@1.0.4
+   - fix for timing attacks
+
+4.4.4 / 2014-06-20
+==================
+
+ * fix `res.attachment` Unicode filenames in Safari
+ * fix "trim prefix" debug message in `express:router`
+ * deps: accepts@~1.0.5
+ * deps: buffer-crc32@0.2.3
+
+4.4.3 / 2014-06-11
+==================
+
+ * fix persistence of modified `req.params[name]` from `app.param()`
+ * deps: accepts@1.0.3
+   - deps: negotiator@0.4.6
+ * deps: debug@1.0.2
+ * deps: send@0.4.3
+   - Do not throw uncatchable error on file open race condition
+   - Use `escape-html` for HTML escaping
+   - deps: debug@1.0.2
+   - deps: finished@1.2.2
+   - deps: fresh@0.2.2
+ * deps: serve-static@1.2.3
+   - Do not throw uncatchable error on file open race condition
+   - deps: send@0.4.3
+
+4.4.2 / 2014-06-09
+==================
+
+ * fix catching errors from top-level handlers
+ * use `vary` module for `res.vary`
+ * deps: debug@1.0.1
+ * deps: proxy-addr@1.0.1
+ * deps: send@0.4.2
+   - fix "event emitter leak" warnings
+   - deps: debug@1.0.1
+   - deps: finished@1.2.1
+ * deps: serve-static@1.2.2
+   - fix "event emitter leak" warnings
+   - deps: send@0.4.2
+ * deps: type-is@1.2.1
+
+4.4.1 / 2014-06-02
+==================
+
+ * deps: methods@1.0.1
+ * deps: send@0.4.1
+   - Send `max-age` in `Cache-Control` in correct format
+ * deps: serve-static@1.2.1
+   - use `escape-html` for escaping
+   - deps: send@0.4.1
+
+4.4.0 / 2014-05-30
+==================
+
+ * custom etag control with `app.set('etag', val)`
+   - `app.set('etag', function(body, encoding){ return '"etag"' })` custom etag generation
+   - `app.set('etag', 'weak')` weak tag
+   - `app.set('etag', 'strong')` strong etag
+   - `app.set('etag', false)` turn off
+   - `app.set('etag', true)` standard etag
+ * mark `res.send` ETag as weak and reduce collisions
+ * update accepts to 1.0.2
+   - Fix interpretation when header not in request
+ * update send to 0.4.0
+   - Calculate ETag with md5 for reduced collisions
+   - Ignore stream errors after request ends
+   - deps: debug@0.8.1
+ * update serve-static to 1.2.0
+   - Calculate ETag with md5 for reduced collisions
+   - Ignore stream errors after request ends
+   - deps: send@0.4.0
+
+4.3.2 / 2014-05-28
+==================
+
+ * fix handling of errors from `router.param()` callbacks
+
+4.3.1 / 2014-05-23
+==================
+
+ * revert "fix behavior of multiple `app.VERB` for the same path"
+   - this caused a regression in the order of route execution
+
+4.3.0 / 2014-05-21
+==================
+
+ * add `req.baseUrl` to access the path stripped from `req.url` in routes
+ * fix behavior of multiple `app.VERB` for the same path
+ * fix issue routing requests among sub routers
+ * invoke `router.param()` only when necessary instead of every match
+ * proper proxy trust with `app.set('trust proxy', trust)`
+   - `app.set('trust proxy', 1)` trust first hop
+   - `app.set('trust proxy', 'loopback')` trust loopback addresses
+   - `app.set('trust proxy', '10.0.0.1')` trust single IP
+   - `app.set('trust proxy', '10.0.0.1/16')` trust subnet
+   - `app.set('trust proxy', '10.0.0.1, 10.0.0.2')` trust list
+   - `app.set('trust proxy', false)` turn off
+   - `app.set('trust proxy', true)` trust everything
+ * set proper `charset` in `Content-Type` for `res.send`
+ * update type-is to 1.2.0
+   - support suffix matching
+
+4.2.0 / 2014-05-11
+==================
+
+ * deprecate `app.del()` -- use `app.delete()` instead
+ * deprecate `res.json(obj, status)` -- use `res.json(status, obj)` instead
+   - the edge-case `res.json(status, num)` requires `res.status(status).json(num)`
+ * deprecate `res.jsonp(obj, status)` -- use `res.jsonp(status, obj)` instead
+   - the edge-case `res.jsonp(status, num)` requires `res.status(status).jsonp(num)`
+ * fix `req.next` when inside router instance
+ * include `ETag` header in `HEAD` requests
+ * keep previous `Content-Type` for `res.jsonp`
+ * support PURGE method
+   - add `app.purge`
+   - add `router.purge`
+   - include PURGE in `app.all`
+ * update debug to 0.8.0
+   - add `enable()` method
+   - change from stderr to stdout
+ * update methods to 1.0.0
+   - add PURGE
+
+4.1.2 / 2014-05-08
+==================
+
+ * fix `req.host` for IPv6 literals
+ * fix `res.jsonp` error if callback param is object
+
+4.1.1 / 2014-04-27
+==================
+
+ * fix package.json to reflect supported node version
+
+4.1.0 / 2014-04-24
+==================
+
+ * pass options from `res.sendfile` to `send`
+ * preserve casing of headers in `res.header` and `res.set`
+ * support unicode file names in `res.attachment` and `res.download`
+ * update accepts to 1.0.1
+   - deps: negotiator@0.4.0
+ * update cookie to 0.1.2
+   - Fix for maxAge == 0
+   - made compat with expires field
+ * update send to 0.3.0
+   - Accept API options in options object
+   - Coerce option types
+   - Control whether to generate etags
+   - Default directory access to 403 when index disabled
+   - Fix sending files with dots without root set
+   - Include file path in etag
+   - Make "Can't set headers after they are sent." catchable
+   - Send full entity-body for multi range requests
+   - Set etags to "weak"
+   - Support "If-Range" header
+   - Support multiple index paths
+   - deps: mime@1.2.11
+ * update serve-static to 1.1.0
+   - Accept options directly to `send` module
+   - Resolve relative paths at middleware setup
+   - Use parseurl to parse the URL from request
+   - deps: send@0.3.0
+ * update type-is to 1.1.0
+   - add non-array values support
+   - add `multipart` as a shorthand
+
+4.0.0 / 2014-04-09
+==================
+
+ * remove:
+   - node 0.8 support
+   - connect and connect's patches except for charset handling
+   - express(1) - moved to [express-generator](https://github.com/expressjs/generator)
+   - `express.createServer()` - it has been deprecated for a long time. Use `express()`
+   - `app.configure` - use logic in your own app code
+   - `app.router` - is removed
+   - `req.auth` - use `basic-auth` instead
+   - `req.accepted*` - use `req.accepts*()` instead
+   - `res.location` - relative URL resolution is removed
+   - `res.charset` - include the charset in the content type when using `res.set()`
+   - all bundled middleware except `static`
+ * change:
+   - `app.route` -> `app.mountpath` when mounting an express app in another express app
+   - `json spaces` no longer enabled by default in development
+   - `req.accepts*` -> `req.accepts*s` - i.e. `req.acceptsEncoding` -> `req.acceptsEncodings`
+   - `req.params` is now an object instead of an array
+   - `res.locals` is no longer a function. It is a plain js object. Treat it as such.
+   - `res.headerSent` -> `res.headersSent` to match node.js ServerResponse object
+ * refactor:
+   - `req.accepts*` with [accepts](https://github.com/expressjs/accepts)
+   - `req.is` with [type-is](https://github.com/expressjs/type-is)
+   - [path-to-regexp](https://github.com/component/path-to-regexp)
+ * add:
+   - `app.router()` - returns the app Router instance
+   - `app.route()` - Proxy to the app's `Router#route()` method to create a new route
+   - Router & Route - public API
+
+3.21.2 / 2015-07-31
+===================
+
+  * deps: connect@2.30.2
+    - deps: body-parser@~1.13.3
+    - deps: compression@~1.5.2
+    - deps: errorhandler@~1.4.2
+    - deps: method-override@~2.3.5
+    - deps: serve-index@~1.7.2
+    - deps: type-is@~1.6.6
+    - deps: vhost@~3.0.1
+  * deps: vary@~1.0.1
+    - Fix setting empty header from empty `field`
+    - perf: enable strict mode
+    - perf: remove argument reassignments
+
+3.21.1 / 2015-07-05
+===================
+
+  * deps: basic-auth@~1.0.3
+  * deps: connect@2.30.1
+    - deps: body-parser@~1.13.2
+    - deps: compression@~1.5.1
+    - deps: errorhandler@~1.4.1
+    - deps: morgan@~1.6.1
+    - deps: pause@0.1.0
+    - deps: qs@4.0.0
+    - deps: serve-index@~1.7.1
+    - deps: type-is@~1.6.4
+
+3.21.0 / 2015-06-18
+===================
+
+  * deps: basic-auth@1.0.2
+    - perf: enable strict mode
+    - perf: hoist regular expression
+    - perf: parse with regular expressions
+    - perf: remove argument reassignment
+  * deps: connect@2.30.0
+    - deps: body-parser@~1.13.1
+    - deps: bytes@2.1.0
+    - deps: compression@~1.5.0
+    - deps: cookie@0.1.3
+    - deps: cookie-parser@~1.3.5
+    - deps: csurf@~1.8.3
+    - deps: errorhandler@~1.4.0
+    - deps: express-session@~1.11.3
+    - deps: finalhandler@0.4.0
+    - deps: fresh@0.3.0
+    - deps: morgan@~1.6.0
+    - deps: serve-favicon@~2.3.0
+    - deps: serve-index@~1.7.0
+    - deps: serve-static@~1.10.0
+    - deps: type-is@~1.6.3
+  * deps: cookie@0.1.3
+    - perf: deduce the scope of try-catch deopt
+    - perf: remove argument reassignments
+  * deps: escape-html@1.0.2
+  * deps: etag@~1.7.0
+    - Always include entity length in ETags for hash length extensions
+    - Generate non-Stats ETags using MD5 only (no longer CRC32)
+    - Improve stat performance by removing hashing
+    - Improve support for JXcore
+    - Remove base64 padding in ETags to shorten
+    - Support "fake" stats objects in environments without fs
+    - Use MD5 instead of MD4 in weak ETags over 1KB
+  * deps: fresh@0.3.0
+    - Add weak `ETag` matching support
+  * deps: mkdirp@0.5.1
+    - Work in global strict mode
+  * deps: send@0.13.0
+    - Allow Node.js HTTP server to set `Date` response header
+    - Fix incorrectly removing `Content-Location` on 304 response
+    - Improve the default redirect response headers
+    - Send appropriate headers on default error response
+    - Use `http-errors` for standard emitted errors
+    - Use `statuses` instead of `http` module for status messages
+    - deps: escape-html@1.0.2
+    - deps: etag@~1.7.0
+    - deps: fresh@0.3.0
+    - deps: on-finished@~2.3.0
+    - perf: enable strict mode
+    - perf: remove unnecessary array allocations
+
+3.20.3 / 2015-05-17
+===================
+
+  * deps: connect@2.29.2
+    - deps: body-parser@~1.12.4
+    - deps: compression@~1.4.4
+    - deps: connect-timeout@~1.6.2
+    - deps: debug@~2.2.0
+    - deps: depd@~1.0.1
+    - deps: errorhandler@~1.3.6
+    - deps: finalhandler@0.3.6
+    - deps: method-override@~2.3.3
+    - deps: morgan@~1.5.3
+    - deps: qs@2.4.2
+    - deps: response-time@~2.3.1
+    - deps: serve-favicon@~2.2.1
+    - deps: serve-index@~1.6.4
+    - deps: serve-static@~1.9.3
+    - deps: type-is@~1.6.2
+  * deps: debug@~2.2.0
+    - deps: ms@0.7.1
+  * deps: depd@~1.0.1
+  * deps: proxy-addr@~1.0.8
+    - deps: ipaddr.js@1.0.1
+  * deps: send@0.12.3
+    - deps: debug@~2.2.0
+    - deps: depd@~1.0.1
+    - deps: etag@~1.6.0
+    - deps: ms@0.7.1
+    - deps: on-finished@~2.2.1
+
+3.20.2 / 2015-03-16
+===================
+
+  * deps: connect@2.29.1
+    - deps: body-parser@~1.12.2
+    - deps: compression@~1.4.3
+    - deps: connect-timeout@~1.6.1
+    - deps: debug@~2.1.3
+    - deps: errorhandler@~1.3.5
+    - deps: express-session@~1.10.4
+    - deps: finalhandler@0.3.4
+    - deps: method-override@~2.3.2
+    - deps: morgan@~1.5.2
+    - deps: qs@2.4.1
+    - deps: serve-index@~1.6.3
+    - deps: serve-static@~1.9.2
+    - deps: type-is@~1.6.1
+  * deps: debug@~2.1.3
+    - Fix high intensity foreground color for bold
+    - deps: ms@0.7.0
+  * deps: merge-descriptors@1.0.0
+  * deps: proxy-addr@~1.0.7
+    - deps: ipaddr.js@0.1.9
+  * deps: send@0.12.2
+    - Throw errors early for invalid `extensions` or `index` options
+    - deps: debug@~2.1.3
+
+3.20.1 / 2015-02-28
+===================
+
+  * Fix `req.host` when using "trust proxy" hops count
+  * Fix `req.protocol`/`req.secure` when using "trust proxy" hops count
+
+3.20.0 / 2015-02-18
+===================
+
+  * Fix `"trust proxy"` setting to inherit when app is mounted
+  * Generate `ETag`s for all request responses
+    - No longer restricted to only responses for `GET` and `HEAD` requests
+  * Use `content-type` to parse `Content-Type` headers
+  * deps: connect@2.29.0
+    - Use `content-type` to parse `Content-Type` headers
+    - deps: body-parser@~1.12.0
+    - deps: compression@~1.4.1
+    - deps: connect-timeout@~1.6.0
+    - deps: cookie-parser@~1.3.4
+    - deps: cookie-signature@1.0.6
+    - deps: csurf@~1.7.0
+    - deps: errorhandler@~1.3.4
+    - deps: express-session@~1.10.3
+    - deps: http-errors@~1.3.1
+    - deps: response-time@~2.3.0
+    - deps: serve-index@~1.6.2
+    - deps: serve-static@~1.9.1
+    - deps: type-is@~1.6.0
+  * deps: cookie-signature@1.0.6
+  * deps: send@0.12.1
+    - Always read the stat size from the file
+    - Fix mutating passed-in `options`
+    - deps: mime@1.3.4
+
+3.19.2 / 2015-02-01
+===================
+
+  * deps: connect@2.28.3
+    - deps: compression@~1.3.1
+    - deps: csurf@~1.6.6
+    - deps: errorhandler@~1.3.3
+    - deps: express-session@~1.10.2
+    - deps: serve-index@~1.6.1
+    - deps: type-is@~1.5.6
+  * deps: proxy-addr@~1.0.6
+    - deps: ipaddr.js@0.1.8
+
+3.19.1 / 2015-01-20
+===================
+
+  * deps: connect@2.28.2
+    - deps: body-parser@~1.10.2
+    - deps: serve-static@~1.8.1
+  * deps: send@0.11.1
+    - Fix root path disclosure
+
+3.19.0 / 2015-01-09
+===================
+
+  * Fix `OPTIONS` responses to include the `HEAD` method property
+  * Use `readline` for prompt in `express(1)`
+  * deps: commander@2.6.0
+  * deps: connect@2.28.1
+    - deps: body-parser@~1.10.1
+    - deps: compression@~1.3.0
+    - deps: connect-timeout@~1.5.0
+    - deps: csurf@~1.6.4
+    - deps: debug@~2.1.1
+    - deps: errorhandler@~1.3.2
+    - deps: express-session@~1.10.1
+    - deps: finalhandler@0.3.3
+    - deps: method-override@~2.3.1
+    - deps: morgan@~1.5.1
+    - deps: serve-favicon@~2.2.0
+    - deps: serve-index@~1.6.0
+    - deps: serve-static@~1.8.0
+    - deps: type-is@~1.5.5
+  * deps: debug@~2.1.1
+  * deps: methods@~1.1.1
+  * deps: proxy-addr@~1.0.5
+    - deps: ipaddr.js@0.1.6
+  * deps: send@0.11.0
+    - deps: debug@~2.1.1
+    - deps: etag@~1.5.1
+    - deps: ms@0.7.0
+    - deps: on-finished@~2.2.0
+
+3.18.6 / 2014-12-12
+===================
+
+  * Fix exception in `req.fresh`/`req.stale` without response headers
+
+3.18.5 / 2014-12-11
+===================
+
+  * deps: connect@2.27.6
+    - deps: compression@~1.2.2
+    - deps: express-session@~1.9.3
+    - deps: http-errors@~1.2.8
+    - deps: serve-index@~1.5.3
+    - deps: type-is@~1.5.4
+
+3.18.4 / 2014-11-23
+===================
+
+  * deps: connect@2.27.4
+    - deps: body-parser@~1.9.3
+    - deps: compression@~1.2.1
+    - deps: errorhandler@~1.2.3
+    - deps: express-session@~1.9.2
+    - deps: qs@2.3.3
+    - deps: serve-favicon@~2.1.7
+    - deps: serve-static@~1.5.1
+    - deps: type-is@~1.5.3
+  * deps: etag@~1.5.1
+  * deps: proxy-addr@~1.0.4
+    - deps: ipaddr.js@0.1.5
+
+3.18.3 / 2014-11-09
+===================
+
+  * deps: connect@2.27.3
+    - Correctly invoke async callback asynchronously
+    - deps: csurf@~1.6.3
+
+3.18.2 / 2014-10-28
+===================
+
+  * deps: connect@2.27.2
+    - Fix handling of URLs containing `://` in the path
+    - deps: body-parser@~1.9.2
+    - deps: qs@2.3.2
+
+3.18.1 / 2014-10-22
+===================
+
+  * Fix internal `utils.merge` deprecation warnings
+  * deps: connect@2.27.1
+    - deps: body-parser@~1.9.1
+    - deps: express-session@~1.9.1
+    - deps: finalhandler@0.3.2
+    - deps: morgan@~1.4.1
+    - deps: qs@2.3.0
+    - deps: serve-static@~1.7.1
+  * deps: send@0.10.1
+    - deps: on-finished@~2.1.1
+
+3.18.0 / 2014-10-17
+===================
+
+  * Use `content-disposition` module for `res.attachment`/`res.download`
+    - Sends standards-compliant `Content-Disposition` header
+    - Full Unicode support
+  * Use `etag` module to generate `ETag` headers
+  * deps: connect@2.27.0
+    - Use `http-errors` module for creating errors
+    - Use `utils-merge` module for merging objects
+    - deps: body-parser@~1.9.0
+    - deps: compression@~1.2.0
+    - deps: connect-timeout@~1.4.0
+    - deps: debug@~2.1.0
+    - deps: depd@~1.0.0
+    - deps: express-session@~1.9.0
+    - deps: finalhandler@0.3.1
+    - deps: method-override@~2.3.0
+    - deps: morgan@~1.4.0
+    - deps: response-time@~2.2.0
+    - deps: serve-favicon@~2.1.6
+    - deps: serve-index@~1.5.0
+    - deps: serve-static@~1.7.0
+  * deps: debug@~2.1.0
+    - Implement `DEBUG_FD` env variable support
+  * deps: depd@~1.0.0
+  * deps: send@0.10.0
+    - deps: debug@~2.1.0
+    - deps: depd@~1.0.0
+    - deps: etag@~1.5.0
+
+3.17.8 / 2014-10-15
+===================
+
+  * deps: connect@2.26.6
+    - deps: compression@~1.1.2
+    - deps: csurf@~1.6.2
+    - deps: errorhandler@~1.2.2
+
+3.17.7 / 2014-10-08
+===================
+
+  * deps: connect@2.26.5
+    - Fix accepting non-object arguments to `logger`
+    - deps: serve-static@~1.6.4
+
+3.17.6 / 2014-10-02
+===================
+
+  * deps: connect@2.26.4
+    - deps: morgan@~1.3.2
+    - deps: type-is@~1.5.2
+
+3.17.5 / 2014-09-24
+===================
+
+  * deps: connect@2.26.3
+    - deps: body-parser@~1.8.4
+    - deps: serve-favicon@~2.1.5
+    - deps: serve-static@~1.6.3
+  * deps: proxy-addr@~1.0.3
+    - Use `forwarded` npm module
+  * deps: send@0.9.3
+    - deps: etag@~1.4.0
+
+3.17.4 / 2014-09-19
+===================
+
+  * deps: connect@2.26.2
+    - deps: body-parser@~1.8.3
+    - deps: qs@2.2.4
+
+3.17.3 / 2014-09-18
+===================
+
+  * deps: proxy-addr@~1.0.2
+    - Fix a global leak when multiple subnets are trusted
+    - deps: ipaddr.js@0.1.3
+
+3.17.2 / 2014-09-15
+===================
+
+  * Use `crc` instead of `buffer-crc32` for speed
+  * deps: connect@2.26.1
+    - deps: body-parser@~1.8.2
+    - deps: depd@0.4.5
+    - deps: express-session@~1.8.2
+    - deps: morgan@~1.3.1
+    - deps: serve-favicon@~2.1.3
+    - deps: serve-static@~1.6.2
+  * deps: depd@0.4.5
+  * deps: send@0.9.2
+    - deps: depd@0.4.5
+    - deps: etag@~1.3.1
+    - deps: range-parser@~1.0.2
+
+3.17.1 / 2014-09-08
+===================
+
+  * Fix error in `req.subdomains` on empty host
+
+3.17.0 / 2014-09-08
+===================
+
+  * Support `X-Forwarded-Host` in `req.subdomains`
+  * Support IP address host in `req.subdomains`
+  * deps: connect@2.26.0
+    - deps: body-parser@~1.8.1
+    - deps: compression@~1.1.0
+    - deps: connect-timeout@~1.3.0
+    - deps: cookie-parser@~1.3.3
+    - deps: cookie-signature@1.0.5
+    - deps: csurf@~1.6.1
+    - deps: debug@~2.0.0
+    - deps: errorhandler@~1.2.0
+    - deps: express-session@~1.8.1
+    - deps: finalhandler@0.2.0
+    - deps: fresh@0.2.4
+    - deps: media-typer@0.3.0
+    - deps: method-override@~2.2.0
+    - deps: morgan@~1.3.0
+    - deps: qs@2.2.3
+    - deps: serve-favicon@~2.1.3
+    - deps: serve-index@~1.2.1
+    - deps: serve-static@~1.6.1
+    - deps: type-is@~1.5.1
+    - deps: vhost@~3.0.0
+  * deps: cookie-signature@1.0.5
+  * deps: debug@~2.0.0
+  * deps: fresh@0.2.4
+  * deps: media-typer@0.3.0
+    - Throw error when parameter format invalid on parse
+  * deps: range-parser@~1.0.2
+  * deps: send@0.9.1
+    - Add `lastModified` option
+    - Use `etag` to generate `ETag` header
+    - deps: debug@~2.0.0
+    - deps: fresh@0.2.4
+  * deps: vary@~1.0.0
+    - Accept valid `Vary` header string as `field`
+
+3.16.10 / 2014-09-04
+====================
+
+  * deps: connect@2.25.10
+    - deps: serve-static@~1.5.4
+  * deps: send@0.8.5
+    - Fix a path traversal issue when using `root`
+    - Fix malicious path detection for empty string path
+
+3.16.9 / 2014-08-29
+===================
+
+  * deps: connect@2.25.9
+    - deps: body-parser@~1.6.7
+    - deps: qs@2.2.2
+
+3.16.8 / 2014-08-27
+===================
+
+  * deps: connect@2.25.8
+    - deps: body-parser@~1.6.6
+    - deps: csurf@~1.4.1
+    - deps: qs@2.2.0
+
+3.16.7 / 2014-08-18
+===================
+
+  * deps: connect@2.25.7
+    - deps: body-parser@~1.6.5
+    - deps: express-session@~1.7.6
+    - deps: morgan@~1.2.3
+    - deps: serve-static@~1.5.3
+  * deps: send@0.8.3
+    - deps: destroy@1.0.3
+    - deps: on-finished@2.1.0
+
+3.16.6 / 2014-08-14
+===================
+
+  * deps: connect@2.25.6
+    - deps: body-parser@~1.6.4
+    - deps: qs@1.2.2
+    - deps: serve-static@~1.5.2
+  * deps: send@0.8.2
+    - Work around `fd` leak in Node.js 0.10 for `fs.ReadStream`
+
+3.16.5 / 2014-08-11
+===================
+
+  * deps: connect@2.25.5
+    - Fix backwards compatibility in `logger`
+
+3.16.4 / 2014-08-10
+===================
+
+  * Fix original URL parsing in `res.location`
+  * deps: connect@2.25.4
+    - Fix `query` middleware breaking with argument
+    - deps: body-parser@~1.6.3
+    - deps: compression@~1.0.11
+    - deps: connect-timeout@~1.2.2
+    - deps: express-session@~1.7.5
+    - deps: method-override@~2.1.3
+    - deps: on-headers@~1.0.0
+    - deps: parseurl@~1.3.0
+    - deps: qs@1.2.1
+    - deps: response-time@~2.0.1
+    - deps: serve-index@~1.1.6
+    - deps: serve-static@~1.5.1
+  * deps: parseurl@~1.3.0
+
+3.16.3 / 2014-08-07
+===================
+
+  * deps: connect@2.25.3
+    - deps: multiparty@3.3.2
+
+3.16.2 / 2014-08-07
+===================
+
+  * deps: connect@2.25.2
+    - deps: body-parser@~1.6.2
+    - deps: qs@1.2.0
+
+3.16.1 / 2014-08-06
+===================
+
+  * deps: connect@2.25.1
+    - deps: body-parser@~1.6.1
+    - deps: qs@1.1.0
+
+3.16.0 / 2014-08-05
+===================
+
+  * deps: connect@2.25.0
+    - deps: body-parser@~1.6.0
+    - deps: compression@~1.0.10
+    - deps: csurf@~1.4.0
+    - deps: express-session@~1.7.4
+    - deps: qs@1.0.2
+    - deps: serve-static@~1.5.0
+  * deps: send@0.8.1
+    - Add `extensions` option
+
+3.15.3 / 2014-08-04
+===================
+
+  * fix `res.sendfile` regression for serving directory index files
+  * deps: connect@2.24.3
+    - deps: serve-index@~1.1.5
+    - deps: serve-static@~1.4.4
+  * deps: send@0.7.4
+    - Fix incorrect 403 on Windows and Node.js 0.11
+    - Fix serving index files without root dir
+
+3.15.2 / 2014-07-27
+===================
+
+  * deps: connect@2.24.2
+    - deps: body-parser@~1.5.2
+    - deps: depd@0.4.4
+    - deps: express-session@~1.7.2
+    - deps: morgan@~1.2.2
+    - deps: serve-static@~1.4.2
+  * deps: depd@0.4.4
+    - Work-around v8 generating empty stack traces
+  * deps: send@0.7.2
+    - deps: depd@0.4.4
+
+3.15.1 / 2014-07-26
+===================
+
+  * deps: connect@2.24.1
+    - deps: body-parser@~1.5.1
+    - deps: depd@0.4.3
+    - deps: express-session@~1.7.1
+    - deps: morgan@~1.2.1
+    - deps: serve-index@~1.1.4
+    - deps: serve-static@~1.4.1
+  * deps: depd@0.4.3
+    - Fix exception when global `Error.stackTraceLimit` is too low
+  * deps: send@0.7.1
+    - deps: depd@0.4.3
+
+3.15.0 / 2014-07-22
+===================
+
+  * Fix `req.protocol` for proxy-direct connections
+  * Pass options from `res.sendfile` to `send`
+  * deps: connect@2.24.0
+    - deps: body-parser@~1.5.0
+    - deps: compression@~1.0.9
+    - deps: connect-timeout@~1.2.1
+    - deps: debug@1.0.4
+    - deps: depd@0.4.2
+    - deps: express-session@~1.7.0
+    - deps: finalhandler@0.1.0
+    - deps: method-override@~2.1.2
+    - deps: morgan@~1.2.0
+    - deps: multiparty@3.3.1
+    - deps: parseurl@~1.2.0
+    - deps: serve-static@~1.4.0
+  * deps: debug@1.0.4
+  * deps: depd@0.4.2
+    - Add `TRACE_DEPRECATION` environment variable
+    - Remove non-standard grey color from color output
+    - Support `--no-deprecation` argument
+    - Support `--trace-deprecation` argument
+  * deps: parseurl@~1.2.0
+    - Cache URLs based on original value
+    - Remove no-longer-needed URL mis-parse work-around
+    - Simplify the "fast-path" `RegExp`
+  * deps: send@0.7.0
+    - Add `dotfiles` option
+    - Cap `maxAge` value to 1 year
+    - deps: debug@1.0.4
+    - deps: depd@0.4.2
+
+3.14.0 / 2014-07-11
+===================
+
+ * add explicit "Rosetta Flash JSONP abuse" protection
+   - previous versions are not vulnerable; this is just explicit protection
+ * deprecate `res.redirect(url, status)` -- use `res.redirect(status, url)` instead
+ * fix `res.send(status, num)` to send `num` as json (not error)
+ * remove unnecessary escaping when `res.jsonp` returns JSON response
+ * deps: basic-auth@1.0.0
+   - support empty password
+   - support empty username
+ * deps: connect@2.23.0
+   - deps: debug@1.0.3
+   - deps: express-session@~1.6.4
+   - deps: method-override@~2.1.0
+   - deps: parseurl@~1.1.3
+   - deps: serve-static@~1.3.1
+  * deps: debug@1.0.3
+    - Add support for multiple wildcards in namespaces
+  * deps: methods@1.1.0
+    - add `CONNECT`
+  * deps: parseurl@~1.1.3
+    - faster parsing of href-only URLs
+
+3.13.0 / 2014-07-03
+===================
+
+ * add deprecation message to `app.configure`
+ * add deprecation message to `req.auth`
+ * use `basic-auth` to parse `Authorization` header
+ * deps: connect@2.22.0
+   - deps: csurf@~1.3.0
+   - deps: express-session@~1.6.1
+   - deps: multiparty@3.3.0
+   - deps: serve-static@~1.3.0
+ * deps: send@0.5.0
+   - Accept string for `maxage` (converted by `ms`)
+   - Include link in default redirect response
+
+3.12.1 / 2014-06-26
+===================
+
+ * deps: connect@2.21.1
+   - deps: cookie-parser@1.3.2
+   - deps: cookie-signature@1.0.4
+   - deps: express-session@~1.5.2
+   - deps: type-is@~1.3.2
+ * deps: cookie-signature@1.0.4
+   - fix for timing attacks
+
+3.12.0 / 2014-06-21
+===================
+
+ * use `media-typer` to alter content-type charset
+ * deps: connect@2.21.0
+   - deprecate `connect(middleware)` -- use `app.use(middleware)` instead
+   - deprecate `connect.createServer()` -- use `connect()` instead
+   - fix `res.setHeader()` patch to work with get -> append -> set pattern
+   - deps: compression@~1.0.8
+   - deps: errorhandler@~1.1.1
+   - deps: express-session@~1.5.0
+   - deps: serve-index@~1.1.3
+
+3.11.0 / 2014-06-19
+===================
+
+ * deprecate things with `depd` module
+ * deps: buffer-crc32@0.2.3
+ * deps: connect@2.20.2
+   - deprecate `verify` option to `json` -- use `body-parser` npm module instead
+   - deprecate `verify` option to `urlencoded` -- use `body-parser` npm module instead
+   - deprecate things with `depd` module
+   - use `finalhandler` for final response handling
+   - use `media-typer` to parse `content-type` for charset
+   - deps: body-parser@1.4.3
+   - deps: connect-timeout@1.1.1
+   - deps: cookie-parser@1.3.1
+   - deps: csurf@1.2.2
+   - deps: errorhandler@1.1.0
+   - deps: express-session@1.4.0
+   - deps: multiparty@3.2.9
+   - deps: serve-index@1.1.2
+   - deps: type-is@1.3.1
+   - deps: vhost@2.0.0
+
+3.10.5 / 2014-06-11
+===================
+
+ * deps: connect@2.19.6
+   - deps: body-parser@1.3.1
+   - deps: compression@1.0.7
+   - deps: debug@1.0.2
+   - deps: serve-index@1.1.1
+   - deps: serve-static@1.2.3
+ * deps: debug@1.0.2
+ * deps: send@0.4.3
+   - Do not throw uncatchable error on file open race condition
+   - Use `escape-html` for HTML escaping
+   - deps: debug@1.0.2
+   - deps: finished@1.2.2
+   - deps: fresh@0.2.2
+
+3.10.4 / 2014-06-09
+===================
+
+ * deps: connect@2.19.5
+   - fix "event emitter leak" warnings
+   - deps: csurf@1.2.1
+   - deps: debug@1.0.1
+   - deps: serve-static@1.2.2
+   - deps: type-is@1.2.1
+ * deps: debug@1.0.1
+ * deps: send@0.4.2
+   - fix "event emitter leak" warnings
+   - deps: finished@1.2.1
+   - deps: debug@1.0.1
+
+3.10.3 / 2014-06-05
+===================
+
+ * use `vary` module for `res.vary`
+ * deps: connect@2.19.4
+   - deps: errorhandler@1.0.2
+   - deps: method-override@2.0.2
+   - deps: serve-favicon@2.0.1
+ * deps: debug@1.0.0
+
+3.10.2 / 2014-06-03
+===================
+
+ * deps: connect@2.19.3
+   - deps: compression@1.0.6
+
+3.10.1 / 2014-06-03
+===================
+
+ * deps: connect@2.19.2
+   - deps: compression@1.0.4
+ * deps: proxy-addr@1.0.1
+
+3.10.0 / 2014-06-02
+===================
+
+ * deps: connect@2.19.1
+   - deprecate `methodOverride()` -- use `method-override` npm module instead
+   - deps: body-parser@1.3.0
+   - deps: method-override@2.0.1
+   - deps: multiparty@3.2.8
+   - deps: response-time@2.0.0
+   - deps: serve-static@1.2.1
+ * deps: methods@1.0.1
+ * deps: send@0.4.1
+   - Send `max-age` in `Cache-Control` in correct format
+
+3.9.0 / 2014-05-30
+==================
+
+ * custom etag control with `app.set('etag', val)`
+   - `app.set('etag', function(body, encoding){ return '"etag"' })` custom etag generation
+   - `app.set('etag', 'weak')` weak tag
+   - `app.set('etag', 'strong')` strong etag
+   - `app.set('etag', false)` turn off
+   - `app.set('etag', true)` standard etag
+ * Include ETag in HEAD requests
+ * mark `res.send` ETag as weak and reduce collisions
+ * update connect to 2.18.0
+   - deps: compression@1.0.3
+   - deps: serve-index@1.1.0
+   - deps: serve-static@1.2.0
+ * update send to 0.4.0
+   - Calculate ETag with md5 for reduced collisions
+   - Ignore stream errors after request ends
+   - deps: debug@0.8.1
+
+3.8.1 / 2014-05-27
+==================
+
+ * update connect to 2.17.3
+   - deps: body-parser@1.2.2
+   - deps: express-session@1.2.1
+   - deps: method-override@1.0.2
+
+3.8.0 / 2014-05-21
+==================
+
+ * keep previous `Content-Type` for `res.jsonp`
+ * set proper `charset` in `Content-Type` for `res.send`
+ * update connect to 2.17.1
+   - fix `res.charset` appending charset when `content-type` has one
+   - deps: express-session@1.2.0
+   - deps: morgan@1.1.1
+   - deps: serve-index@1.0.3
+
+3.7.0 / 2014-05-18
+==================
+
+ * proper proxy trust with `app.set('trust proxy', trust)`
+   - `app.set('trust proxy', 1)` trust first hop
+   - `app.set('trust proxy', 'loopback')` trust loopback addresses
+   - `app.set('trust proxy', '10.0.0.1')` trust single IP
+   - `app.set('trust proxy', '10.0.0.1/16')` trust subnet
+   - `app.set('trust proxy', '10.0.0.1, 10.0.0.2')` trust list
+   - `app.set('trust proxy', false)` turn off
+   - `app.set('trust proxy', true)` trust everything
+ * update connect to 2.16.2
+   - deprecate `res.headerSent` -- use `res.headersSent`
+   - deprecate `res.on("header")` -- use on-headers module instead
+   - fix edge-case in `res.appendHeader` that would append in wrong order
+   - json: use body-parser
+   - urlencoded: use body-parser
+   - dep: bytes@1.0.0
+   - dep: cookie-parser@1.1.0
+   - dep: csurf@1.2.0
+   - dep: express-session@1.1.0
+   - dep: method-override@1.0.1
+
+3.6.0 / 2014-05-09
+==================
+
+ * deprecate `app.del()` -- use `app.delete()` instead
+ * deprecate `res.json(obj, status)` -- use `res.json(status, obj)` instead
+   - the edge-case `res.json(status, num)` requires `res.status(status).json(num)`
+ * deprecate `res.jsonp(obj, status)` -- use `res.jsonp(status, obj)` instead
+   - the edge-case `res.jsonp(status, num)` requires `res.status(status).jsonp(num)`
+ * support PURGE method
+   - add `app.purge`
+   - add `router.purge`
+   - include PURGE in `app.all`
+ * update connect to 2.15.0
+   * Add `res.appendHeader`
+   * Call error stack even when response has been sent
+   * Patch `res.headerSent` to return Boolean
+   * Patch `res.headersSent` for node.js 0.8
+   * Prevent default 404 handler after response sent
+   * dep: compression@1.0.2
+   * dep: connect-timeout@1.1.0
+   * dep: debug@^0.8.0
+   * dep: errorhandler@1.0.1
+   * dep: express-session@1.0.4
+   * dep: morgan@1.0.1
+   * dep: serve-favicon@2.0.0
+   * dep: serve-index@1.0.2
+ * update debug to 0.8.0
+   * add `enable()` method
+   * change from stderr to stdout
+ * update methods to 1.0.0
+   - add PURGE
+ * update mkdirp to 0.5.0
+
+3.5.3 / 2014-05-08
+==================
+
+ * fix `req.host` for IPv6 literals
+ * fix `res.jsonp` error if callback param is object
+
+3.5.2 / 2014-04-24
+==================
+
+ * update connect to 2.14.5
+ * update cookie to 0.1.2
+ * update mkdirp to 0.4.0
+ * update send to 0.3.0
+
+3.5.1 / 2014-03-25
+==================
+
+ * pin less-middleware in generated app
+
+3.5.0 / 2014-03-06
+==================
+
+ * bump deps
+
+3.4.8 / 2014-01-13
+==================
+
+ * prevent incorrect automatic OPTIONS responses #1868 @dpatti
+ * update binary and examples for jade 1.0 #1876 @yossi, #1877 @reqshark, #1892 @matheusazzi
+ * throw 400 in case of malformed paths @rlidwka
+
+3.4.7 / 2013-12-10
+==================
+
+ * update connect
+
+3.4.6 / 2013-12-01
+==================
+
+ * update connect (raw-body)
+
+3.4.5 / 2013-11-27
+==================
+
+ * update connect
+ * res.location: remove leading ./ #1802 @kapouer
+ * res.redirect: fix `res.redirect('toString') #1829 @michaelficarra
+ * res.send: always send ETag when content-length > 0
+ * router: add Router.all() method
+
+3.4.4 / 2013-10-29
+==================
+
+ * update connect
+ * update supertest
+ * update methods
+ * express(1): replace bodyParser() with urlencoded() and json() #1795 @chirag04
+
+3.4.3 / 2013-10-23
+==================
+
+ * update connect
+
+3.4.2 / 2013-10-18
+==================
+
+ * update connect
+ * downgrade commander
+
+3.4.1 / 2013-10-15
+==================
+
+ * update connect
+ * update commander
+ * jsonp: check if callback is a function
+ * router: wrap encodeURIComponent in a try/catch #1735 (@lxe)
+ * res.format: now includes charset @1747 (@sorribas)
+ * res.links: allow multiple calls @1746 (@sorribas)
+
+3.4.0 / 2013-09-07
+==================
+
+ * add res.vary(). Closes #1682
+ * update connect
+
+3.3.8 / 2013-09-02
+==================
+
+ * update connect
+
+3.3.7 / 2013-08-28
+==================
+
+ * update connect
+
+3.3.6 / 2013-08-27
+==================
+
+ * Revert "remove charset from json responses. Closes #1631" (causes issues in some clients)
+ * add: req.accepts take an argument list
+
+3.3.4 / 2013-07-08
+==================
+
+ * update send and connect
+
+3.3.3 / 2013-07-04
+==================
+
+ * update connect
+
+3.3.2 / 2013-07-03
+==================
+
+ * update connect
+ * update send
+ * remove .version export
+
+3.3.1 / 2013-06-27
+==================
+
+ * update connect
+
+3.3.0 / 2013-06-26
+==================
+
+ * update connect
+ * add support for multiple X-Forwarded-Proto values. Closes #1646
+ * change: remove charset from json responses. Closes #1631
+ * change: return actual booleans from req.accept* functions
+ * fix jsonp callback array throw
+
+3.2.6 / 2013-06-02
+==================
+
+ * update connect
+
+3.2.5 / 2013-05-21
+==================
+
+ * update connect
+ * update node-cookie
+ * add: throw a meaningful error when there is no default engine
+ * change generation of ETags with res.send() to GET requests only. Closes #1619
+
+3.2.4 / 2013-05-09
+==================
+
+  * fix `req.subdomains` when no Host is present
+  * fix `req.host` when no Host is present, return undefined
+
+3.2.3 / 2013-05-07
+==================
+
+  * update connect / qs
+
+3.2.2 / 2013-05-03
+==================
+
+  * update qs
+
+3.2.1 / 2013-04-29
+==================
+
+  * add app.VERB() paths array deprecation warning
+  * update connect
+  * update qs and remove all ~ semver crap
+  * fix: accept number as value of Signed Cookie
+
+3.2.0 / 2013-04-15
+==================
+
+  * add "view" constructor setting to override view behaviour
+  * add req.acceptsEncoding(name)
+  * add req.acceptedEncodings
+  * revert cookie signature change causing session race conditions
+  * fix sorting of Accept values of the same quality
+
+3.1.2 / 2013-04-12
+==================
+
+  * add support for custom Accept parameters
+  * update cookie-signature
+
+3.1.1 / 2013-04-01
+==================
+
+  * add X-Forwarded-Host support to `req.host`
+  * fix relative redirects
+  * update mkdirp
+  * update buffer-crc32
+  * remove legacy app.configure() method from app template.
+
+3.1.0 / 2013-01-25
+==================
+
+  * add support for leading "." in "view engine" setting
+  * add array support to `res.set()`
+  * add node 0.8.x to travis.yml
+  * add "subdomain offset" setting for tweaking `req.subdomains`
+  * add `res.location(url)` implementing `res.redirect()`-like setting of Location
+  * use app.get() for x-powered-by setting for inheritance
+  * fix colons in passwords for `req.auth`
+
+3.0.6 / 2013-01-04
+==================
+
+  * add http verb methods to Router
+  * update connect
+  * fix mangling of the `res.cookie()` options object
+  * fix jsonp whitespace escape. Closes #1132
+
+3.0.5 / 2012-12-19
+==================
+
+  * add throwing when a non-function is passed to a route
+  * fix: explicitly remove Transfer-Encoding header from 204 and 304 responses
+  * revert "add 'etag' option"
+
+3.0.4 / 2012-12-05
+==================
+
+  * add 'etag' option to disable `res.send()` Etags
+  * add escaping of urls in text/plain in `res.redirect()`
+    for old browsers interpreting as html
+  * change crc32 module for a more liberal license
+  * update connect
+
+3.0.3 / 2012-11-13
+==================
+
+  * update connect
+  * update cookie module
+  * fix cookie max-age
+
+3.0.2 / 2012-11-08
+==================
+
+  * add OPTIONS to cors example. Closes #1398
+  * fix route chaining regression. Closes #1397
+
+3.0.1 / 2012-11-01
+==================
+
+  * update connect
+
+3.0.0 / 2012-10-23
+==================
+
+  * add `make clean`
+  * add "Basic" check to req.auth
+  * add `req.auth` test coverage
+  * add cb && cb(payload) to `res.jsonp()`. Closes #1374
+  * add backwards compat for `res.redirect()` status. Closes #1336
+  * add support for `res.json()` to retain previously defined Content-Types. Closes #1349
+  * update connect
+  * change `res.redirect()` to utilize a pathname-relative Location again. Closes #1382
+  * remove non-primitive string support for `res.send()`
+  * fix view-locals example. Closes #1370
+  * fix route-separation example
+
+3.0.0rc5 / 2012-09-18
+==================
+
+  * update connect
+  * add redis search example
+  * add static-files example
+  * add "x-powered-by" setting (`app.disable('x-powered-by')`)
+  * add "application/octet-stream" redirect Accept test case. Closes #1317
+
+3.0.0rc4 / 2012-08-30
+==================
+
+  * add `res.jsonp()`. Closes #1307
+  * add "verbose errors" option to error-pages example
+  * add another route example to express(1) so people are not so confused
+  * add redis online user activity tracking example
+  * update connect dep
+  * fix etag quoting. Closes #1310
+  * fix error-pages 404 status
+  * fix jsonp callback char restrictions
+  * remove old OPTIONS default response
+
+3.0.0rc3 / 2012-08-13
+==================
+
+  * update connect dep
+  * fix signed cookies to work with `connect.cookieParser()` ("s:" prefix was missing) [tnydwrds]
+  * fix `res.render()` clobbering of "locals"
+
+3.0.0rc2 / 2012-08-03
+==================
+
+  * add CORS example
+  * update connect dep
+  * deprecate `.createServer()` & remove old stale examples
+  * fix: escape `res.redirect()` link
+  * fix vhost example
+
+3.0.0rc1 / 2012-07-24
+==================
+
+  * add more examples to view-locals
+  * add scheme-relative redirects (`res.redirect("//foo.com")`) support
+  * update cookie dep
+  * update connect dep
+  * update send dep
+  * fix `express(1)` -h flag, use -H for hogan. Closes #1245
+  * fix `res.sendfile()` socket error handling regression
+
+3.0.0beta7 / 2012-07-16
+==================
+
+  * update connect dep for `send()` root normalization regression
+
+3.0.0beta6 / 2012-07-13
+==================
+
+  * add `err.view` property for view errors. Closes #1226
+  * add "jsonp callback name" setting
+  * add support for "/foo/:bar*" non-greedy matches
+  * change `res.sendfile()` to use `send()` module
+  * change `res.send` to use "response-send" module
+  * remove `app.locals.use` and `res.locals.use`, use regular middleware
+
+3.0.0beta5 / 2012-07-03
+==================
+
+  * add "make check" support
+  * add route-map example
+  * add `res.json(obj, status)` support back for BC
+  * add "methods" dep, remove internal methods module
+  * update connect dep
+  * update auth example to utilize cores pbkdf2
+  * updated tests to use "supertest"
+
+3.0.0beta4 / 2012-06-25
+==================
+
+  * Added `req.auth`
+  * Added `req.range(size)`
+  * Added `res.links(obj)`
+  * Added `res.send(body, status)` support back for backwards compat
+  * Added `.default()` support to `res.format()`
+  * Added 2xx / 304 check to `req.fresh`
+  * Revert "Added + support to the router"
+  * Fixed `res.send()` freshness check, respect res.statusCode
+
+3.0.0beta3 / 2012-06-15
+==================
+
+  * Added hogan `--hjs` to express(1) [nullfirm]
+  * Added another example to content-negotiation
+  * Added `fresh` dep
+  * Changed: `res.send()` always checks freshness
+  * Fixed: expose connects mime module. Closes #1165
+
+3.0.0beta2 / 2012-06-06
+==================
+
+  * Added `+` support to the router
+  * Added `req.host`
+  * Changed `req.param()` to check route first
+  * Update connect dep
+
+3.0.0beta1 / 2012-06-01
+==================
+
+  * Added `res.format()` callback to override default 406 behaviour
+  * Fixed `res.redirect()` 406. Closes #1154
+
+3.0.0alpha5 / 2012-05-30
+==================
+
+  * Added `req.ip`
+  * Added `{ signed: true }` option to `res.cookie()`
+  * Removed `res.signedCookie()`
+  * Changed: dont reverse `req.ips`
+  * Fixed "trust proxy" setting check for `req.ips`
+
+3.0.0alpha4 / 2012-05-09
+==================
+
+  * Added: allow `[]` in jsonp callback. Closes #1128
+  * Added `PORT` env var support in generated template. Closes #1118 [benatkin]
+  * Updated: connect 2.2.2
+
+3.0.0alpha3 / 2012-05-04
+==================
+
+  * Added public `app.routes`. Closes #887
+  * Added _view-locals_ example
+  * Added _mvc_ example
+  * Added `res.locals.use()`. Closes #1120
+  * Added conditional-GET support to `res.send()`
+  * Added: coerce `res.set()` values to strings
+  * Changed: moved `static()` in generated apps below router
+  * Changed: `res.send()` only set ETag when not previously set
+  * Changed connect 2.2.1 dep
+  * Changed: `make test` now runs unit / acceptance tests
+  * Fixed req/res proto inheritance
+
+3.0.0alpha2 / 2012-04-26
+==================
+
+  * Added `make benchmark` back
+  * Added `res.send()` support for `String` objects
+  * Added client-side data exposing example
+  * Added `res.header()` and `req.header()` aliases for BC
+  * Added `express.createServer()` for BC
+  * Perf: memoize parsed urls
+  * Perf: connect 2.2.0 dep
+  * Changed: make `expressInit()` middleware self-aware
+  * Fixed: use app.get() for all core settings
+  * Fixed redis session example
+  * Fixed session example. Closes #1105
+  * Fixed generated express dep. Closes #1078
+
+3.0.0alpha1 / 2012-04-15
+==================
+
+  * Added `app.locals.use(callback)`
+  * Added `app.locals` object
+  * Added `app.locals(obj)`
+  * Added `res.locals` object
+  * Added `res.locals(obj)`
+  * Added `res.format()` for content-negotiation
+  * Added `app.engine()`
+  * Added `res.cookie()` JSON cookie support
+  * Added "trust proxy" setting
+  * Added `req.subdomains`
+  * Added `req.protocol`
+  * Added `req.secure`
+  * Added `req.path`
+  * Added `req.ips`
+  * Added `req.fresh`
+  * Added `req.stale`
+  * Added comma-delimited / array support for `req.accepts()`
+  * Added debug instrumentation
+  * Added `res.set(obj)`
+  * Added `res.set(field, value)`
+  * Added `res.get(field)`
+  * Added `app.get(setting)`. Closes #842
+  * Added `req.acceptsLanguage()`
+  * Added `req.acceptsCharset()`
+  * Added `req.accepted`
+  * Added `req.acceptedLanguages`
+  * Added `req.acceptedCharsets`
+  * Added "json replacer" setting
+  * Added "json spaces" setting
+  * Added X-Forwarded-Proto support to `res.redirect()`. Closes #92
+  * Added `--less` support to express(1)
+  * Added `express.response` prototype
+  * Added `express.request` prototype
+  * Added `express.application` prototype
+  * Added `app.path()`
+  * Added `app.render()`
+  * Added `res.type()` to replace `res.contentType()`
+  * Changed: `res.redirect()` to add relative support
+  * Changed: enable "jsonp callback" by default
+  * Changed: renamed "case sensitive routes" to "case sensitive routing"
+  * Rewrite of all tests with mocha
+  * Removed "root" setting
+  * Removed `res.redirect('home')` support
+  * Removed `req.notify()`
+  * Removed `app.register()`
+  * Removed `app.redirect()`
+  * Removed `app.is()`
+  * Removed `app.helpers()`
+  * Removed `app.dynamicHelpers()`
+  * Fixed `res.sendfile()` with non-GET. Closes #723
+  * Fixed express(1) public dir for windows. Closes #866
+
+2.5.9/ 2012-04-02
+==================
+
+  * Added support for PURGE request method [pbuyle]
+  * Fixed `express(1)` generated app `app.address()` before `listening` [mmalecki]
+
+2.5.8 / 2012-02-08
+==================
+
+  * Update mkdirp dep. Closes #991
+
+2.5.7 / 2012-02-06
+==================
+
+  * Fixed `app.all` duplicate DELETE requests [mscdex]
+
+2.5.6 / 2012-01-13
+==================
+
+  * Updated hamljs dev dep. Closes #953
+
+2.5.5 / 2012-01-08
+==================
+
+  * Fixed: set `filename` on cached templates [matthewleon]
+
+2.5.4 / 2012-01-02
+==================
+
+  * Fixed `express(1)` eol on 0.4.x. Closes #947
+
+2.5.3 / 2011-12-30
+==================
+
+  * Fixed `req.is()` when a charset is present
+
+2.5.2 / 2011-12-10
+==================
+
+  * Fixed: express(1) LF -> CRLF for windows
+
+2.5.1 / 2011-11-17
+==================
+
+  * Changed: updated connect to 1.8.x
+  * Removed sass.js support from express(1)
+
+2.5.0 / 2011-10-24
+==================
+
+  * Added ./routes dir for generated app by default
+  * Added npm install reminder to express(1) app gen
+  * Added 0.5.x support
+  * Removed `make test-cov` since it wont work with node 0.5.x
+  * Fixed express(1) public dir for windows. Closes #866
+
+2.4.7 / 2011-10-05
+==================
+
+  * Added mkdirp to express(1). Closes #795
+  * Added simple _json-config_ example
+  * Added  shorthand for the parsed request's pathname via `req.path`
+  * Changed connect dep to 1.7.x to fix npm issue...
+  * Fixed `res.redirect()` __HEAD__ support. [reported by xerox]
+  * Fixed `req.flash()`, only escape args
+  * Fixed absolute path checking on windows. Closes #829 [reported by andrewpmckenzie]
+
+2.4.6 / 2011-08-22
+==================
+
+  * Fixed multiple param callback regression. Closes #824 [reported by TroyGoode]
+
+2.4.5 / 2011-08-19
+==================
+
+  * Added support for routes to handle errors. Closes #809
+  * Added `app.routes.all()`. Closes #803
+  * Added "basepath" setting to work in conjunction with reverse proxies etc.
+  * Refactored `Route` to use a single array of callbacks
+  * Added support for multiple callbacks for `app.param()`. Closes #801
+Closes #805
+  * Changed: removed .call(self) for route callbacks
+  * Dependency: `qs >= 0.3.1`
+  * Fixed `res.redirect()` on windows due to `join()` usage. Closes #808
+
+2.4.4 / 2011-08-05
+==================
+
+  * Fixed `res.header()` intention of a set, even when `undefined`
+  * Fixed `*`, value no longer required
+  * Fixed `res.send(204)` support. Closes #771
+
+2.4.3 / 2011-07-14
+==================
+
+  * Added docs for `status` option special-case. Closes #739
+  * Fixed `options.filename`, exposing the view path to template engines
+
+2.4.2. / 2011-07-06
+==================
+
+  * Revert "removed jsonp stripping" for XSS
+
+2.4.1 / 2011-07-06
+==================
+
+  * Added `res.json()` JSONP support. Closes #737
+  * Added _extending-templates_ example. Closes #730
+  * Added "strict routing" setting for trailing slashes
+  * Added support for multiple envs in `app.configure()` calls. Closes #735
+  * Changed: `res.send()` using `res.json()`
+  * Changed: when cookie `path === null` don't default it
+  * Changed; default cookie path to "home" setting. Closes #731
+  * Removed _pids/logs_ creation from express(1)
+
+2.4.0 / 2011-06-28
+==================
+
+  * Added chainable `res.status(code)`
+  * Added `res.json()`, an explicit version of `res.send(obj)`
+  * Added simple web-service example
+
+2.3.12 / 2011-06-22
+==================
+
+  * \#express is now on freenode! come join!
+  * Added `req.get(field, param)`
+  * Added links to Japanese documentation, thanks @hideyukisaito!
+  * Added; the `express(1)` generated app outputs the env
+  * Added `content-negotiation` example
+  * Dependency: connect >= 1.5.1 < 2.0.0
+  * Fixed view layout bug. Closes #720
+  * Fixed; ignore body on 304. Closes #701
+
+2.3.11 / 2011-06-04
+==================
+
+  * Added `npm test`
+  * Removed generation of dummy test file from `express(1)`
+  * Fixed; `express(1)` adds express as a dep
+  * Fixed; prune on `prepublish`
+
+2.3.10 / 2011-05-27
+==================
+
+  * Added `req.route`, exposing the current route
+  * Added _package.json_ generation support to `express(1)`
+  * Fixed call to `app.param()` function for optional params. Closes #682
+
+2.3.9 / 2011-05-25
+==================
+
+  * Fixed bug-ish with `../' in `res.partial()` calls
+
+2.3.8 / 2011-05-24
+==================
+
+  * Fixed `app.options()`
+
+2.3.7 / 2011-05-23
+==================
+
+  * Added route `Collection`, ex: `app.get('/user/:id').remove();`
+  * Added support for `app.param(fn)` to define param logic
+  * Removed `app.param()` support for callback with return value
+  * Removed module.parent check from express(1) generated app. Closes #670
+  * Refactored router. Closes #639
+
+2.3.6 / 2011-05-20
+==================
+
+  * Changed; using devDependencies instead of git submodules
+  * Fixed redis session example
+  * Fixed markdown example
+  * Fixed view caching, should not be enabled in development
+
+2.3.5 / 2011-05-20
+==================
+
+  * Added export `.view` as alias for `.View`
+
+2.3.4 / 2011-05-08
+==================
+
+  * Added `./examples/say`
+  * Fixed `res.sendfile()` bug preventing the transfer of files with spaces
+
+2.3.3 / 2011-05-03
+==================
+
+  * Added "case sensitive routes" option.
+  * Changed; split methods supported per rfc [slaskis]
+  * Fixed route-specific middleware when using the same callback function several times
+
+2.3.2 / 2011-04-27
+==================
+
+  * Fixed view hints
+
+2.3.1 / 2011-04-26
+==================
+
+  * Added `app.match()` as `app.match.all()`
+  * Added `app.lookup()` as `app.lookup.all()`
+  * Added `app.remove()` for `app.remove.all()`
+  * Added `app.remove.VERB()`
+  * Fixed template caching collision issue. Closes #644
+  * Moved router over from connect and started refactor
+
+2.3.0 / 2011-04-25
+==================
+
+  * Added options support to `res.clearCookie()`
+  * Added `res.helpers()` as alias of `res.locals()`
+  * Added; json defaults to UTF-8 with `res.send()`. Closes #632. [Daniel   * Dependency `connect >= 1.4.0`
+  * Changed; auto set Content-Type in res.attachement [Aaron Heckmann]
+  * Renamed "cache views" to "view cache". Closes #628
+  * Fixed caching of views when using several apps. Closes #637
+  * Fixed gotcha invoking `app.param()` callbacks once per route middleware.
+Closes #638
+  * Fixed partial lookup precedence. Closes #631
+Shaw]
+
+2.2.2 / 2011-04-12
+==================
+
+  * Added second callback support for `res.download()` connection errors
+  * Fixed `filename` option passing to template engine
+
+2.2.1 / 2011-04-04
+==================
+
+  * Added `layout(path)` helper to change the layout within a view. Closes #610
+  * Fixed `partial()` collection object support.
+    Previously only anything with `.length` would work.
+    When `.length` is present one must still be aware of holes,
+    however now `{ collection: {foo: 'bar'}}` is valid, exposes
+    `keyInCollection` and `keysInCollection`.
+
+  * Performance improved with better view caching
+  * Removed `request` and `response` locals
+  * Changed; errorHandler page title is now `Express` instead of `Connect`
+
+2.2.0 / 2011-03-30
+==================
+
+  * Added `app.lookup.VERB()`, ex `app.lookup.put('/user/:id')`. Closes #606
+  * Added `app.match.VERB()`, ex `app.match.put('/user/12')`. Closes #606
+  * Added `app.VERB(path)` as alias of `app.lookup.VERB()`.
+  * Dependency `connect >= 1.2.0`
+
+2.1.1 / 2011-03-29
+==================
+
+  * Added; expose `err.view` object when failing to locate a view
+  * Fixed `res.partial()` call `next(err)` when no callback is given [reported by aheckmann]
+  * Fixed; `res.send(undefined)` responds with 204 [aheckmann]
+
+2.1.0 / 2011-03-24
+==================
+
+  * Added `<root>/_?<name>` partial lookup support. Closes #447
+  * Added `request`, `response`, and `app` local variables
+  * Added `settings` local variable, containing the app's settings
+  * Added `req.flash()` exception if `req.session` is not available
+  * Added `res.send(bool)` support (json response)
+  * Fixed stylus example for latest version
+  * Fixed; wrap try/catch around `res.render()`
+
+2.0.0 / 2011-03-17
+==================
+
+  * Fixed up index view path alternative.
+  * Changed; `res.locals()` without object returns the locals
+
+2.0.0rc3 / 2011-03-17
+==================
+
+  * Added `res.locals(obj)` to compliment `res.local(key, val)`
+  * Added `res.partial()` callback support
+  * Fixed recursive error reporting issue in `res.render()`
+
+2.0.0rc2 / 2011-03-17
+==================
+
+  * Changed; `partial()` "locals" are now optional
+  * Fixed `SlowBuffer` support. Closes #584 [reported by tyrda01]
+  * Fixed .filename view engine option [reported by drudge]
+  * Fixed blog example
+  * Fixed `{req,res}.app` reference when mounting [Ben Weaver]
+
+2.0.0rc / 2011-03-14
+==================
+
+  * Fixed; expose `HTTPSServer` constructor
+  * Fixed express(1) default test charset. Closes #579 [reported by secoif]
+  * Fixed; default charset to utf-8 instead of utf8 for lame IE [reported by NickP]
+
+2.0.0beta3 / 2011-03-09
+==================
+
+  * Added support for `res.contentType()` literal
+    The original `res.contentType('.json')`,
+    `res.contentType('application/json')`, and `res.contentType('json')`
+    will work now.
+  * Added `res.render()` status option support back
+  * Added charset option for `res.render()`
+  * Added `.charset` support (via connect 1.0.4)
+  * Added view resolution hints when in development and a lookup fails
+  * Added layout lookup support relative to the page view.
+    For example while rendering `./views/user/index.jade` if you create
+    `./views/user/layout.jade` it will be used in favour of the root layout.
+  * Fixed `res.redirect()`. RFC states absolute url [reported by unlink]
+  * Fixed; default `res.send()` string charset to utf8
+  * Removed `Partial` constructor (not currently used)
+
+2.0.0beta2 / 2011-03-07
+==================
+
+  * Added res.render() `.locals` support back to aid in migration process
+  * Fixed flash example
+
+2.0.0beta / 2011-03-03
+==================
+
+  * Added HTTPS support
+  * Added `res.cookie()` maxAge support
+  * Added `req.header()` _Referrer_ / _Referer_ special-case, either works
+  * Added mount support for `res.redirect()`, now respects the mount-point
+  * Added `union()` util, taking place of `merge(clone())` combo
+  * Added stylus support to express(1) generated app
+  * Added secret to session middleware used in examples and generated app
+  * Added `res.local(name, val)` for progressive view locals
+  * Added default param support to `req.param(name, default)`
+  * Added `app.disabled()` and `app.enabled()`
+  * Added `app.register()` support for omitting leading ".", either works
+  * Added `res.partial()`, using the same interface as `partial()` within a view. Closes #539
+  * Added `app.param()` to map route params to async/sync logic
+  * Added; aliased `app.helpers()` as `app.locals()`. Closes #481
+  * Added extname with no leading "." support to `res.contentType()`
+  * Added `cache views` setting, defaulting to enabled in "production" env
+  * Added index file partial resolution, eg: partial('user') may try _views/user/index.jade_.
+  * Added `req.accepts()` support for extensions
+  * Changed; `res.download()` and `res.sendfile()` now utilize Connect's
+    static file server `connect.static.send()`.
+  * Changed; replaced `connect.utils.mime()` with npm _mime_ module
+  * Changed; allow `req.query` to be pre-defined (via middleware or other parent
+  * Changed view partial resolution, now relative to parent view
+  * Changed view engine signature. no longer `engine.render(str, options, callback)`, now `engine.compile(str, options) -> Function`, the returned function accepts `fn(locals)`.
+  * Fixed `req.param()` bug returning Array.prototype methods. Closes #552
+  * Fixed; using `Stream#pipe()` instead of `sys.pump()` in `res.sendfile()`
+  * Fixed; using _qs_ module instead of _querystring_
+  * Fixed; strip unsafe chars from jsonp callbacks
+  * Removed "stream threshold" setting
+
+1.0.8 / 2011-03-01
+==================
+
+  * Allow `req.query` to be pre-defined (via middleware or other parent app)
+  * "connect": ">= 0.5.0 < 1.0.0". Closes #547
+  * Removed the long deprecated __EXPRESS_ENV__ support
+
+1.0.7 / 2011-02-07
+==================
+
+  * Fixed `render()` setting inheritance.
+    Mounted apps would not inherit "view engine"
+
+1.0.6 / 2011-02-07
+==================
+
+  * Fixed `view engine` setting bug when period is in dirname
+
+1.0.5 / 2011-02-05
+==================
+
+  * Added secret to generated app `session()` call
+
+1.0.4 / 2011-02-05
+==================
+
+  * Added `qs` dependency to _package.json_
+  * Fixed namespaced `require()`s for latest connect support
+
+1.0.3 / 2011-01-13
+==================
+
+  * Remove unsafe characters from JSONP callback names [Ryan Grove]
+
+1.0.2 / 2011-01-10
+==================
+
+  * Removed nested require, using `connect.router`
+
+1.0.1 / 2010-12-29
+==================
+
+  * Fixed for middleware stacked via `createServer()`
+    previously the `foo` middleware passed to `createServer(foo)`
+    would not have access to Express methods such as `res.send()`
+    or props like `req.query` etc.
+
+1.0.0 / 2010-11-16
+==================
+
+  * Added; deduce partial object names from the last segment.
+    For example by default `partial('forum/post', postObject)` will
+    give you the _post_ object, providing a meaningful default.
+  * Added http status code string representation to `res.redirect()` body
+  * Added; `res.redirect()` supporting _text/plain_ and _text/html_ via __Accept__.
+  * Added `req.is()` to aid in content negotiation
+  * Added partial local inheritance [suggested by masylum]. Closes #102
+    providing access to parent template locals.
+  * Added _-s, --session[s]_ flag to express(1) to add session related middleware
+  * Added _--template_ flag to express(1) to specify the
+    template engine to use.
+  * Added _--css_ flag to express(1) to specify the
+    stylesheet engine to use (or just plain css by default).
+  * Added `app.all()` support [thanks aheckmann]
+  * Added partial direct object support.
+    You may now `partial('user', user)` providing the "user" local,
+    vs previously `partial('user', { object: user })`.
+  * Added _route-separation_ example since many people question ways
+    to do this with CommonJS modules. Also view the _blog_ example for
+    an alternative.
+  * Performance; caching view path derived partial object names
+  * Fixed partial local inheritance precedence. [reported by Nick Poulden] Closes #454
+  * Fixed jsonp support; _text/javascript_ as per mailinglist discussion
+
+1.0.0rc4 / 2010-10-14
+==================
+
+  * Added _NODE_ENV_ support, _EXPRESS_ENV_ is deprecated and will be removed in 1.0.0
+  * Added route-middleware support (very helpful, see the [docs](http://expressjs.com/guide.html#Route-Middleware))
+  * Added _jsonp callback_ setting to enable/disable jsonp autowrapping [Dav Glass]
+  * Added callback query check on response.send to autowrap JSON objects for simple webservice implementations [Dav Glass]
+  * Added `partial()` support for array-like collections. Closes #434
+  * Added support for swappable querystring parsers
+  * Added session usage docs. Closes #443
+  * Added dynamic helper caching. Closes #439 [suggested by maritz]
+  * Added authentication example
+  * Added basic Range support to `res.sendfile()` (and `res.download()` etc)
+  * Changed; `express(1)` generated app using 2 spaces instead of 4
+  * Default env to "development" again [aheckmann]
+  * Removed _context_ option is no more, use "scope"
+  * Fixed; exposing _./support_ libs to examples so they can run without installs
+  * Fixed mvc example
+
+1.0.0rc3 / 2010-09-20
+==================
+
+  * Added confirmation for `express(1)` app generation. Closes #391
+  * Added extending of flash formatters via `app.flashFormatters`
+  * Added flash formatter support. Closes #411
+  * Added streaming support to `res.sendfile()` using `sys.pump()` when >= "stream threshold"
+  * Added _stream threshold_ setting for `res.sendfile()`
+  * Added `res.send()` __HEAD__ support
+  * Added `res.clearCookie()`
+  * Added `res.cookie()`
+  * Added `res.render()` headers option
+  * Added `res.redirect()` response bodies
+  * Added `res.render()` status option support. Closes #425 [thanks aheckmann]
+  * Fixed `res.sendfile()` responding with 403 on malicious path
+  * Fixed `res.download()` bug; when an error occurs remove _Content-Disposition_
+  * Fixed; mounted apps settings now inherit from parent app [aheckmann]
+  * Fixed; stripping Content-Length / Content-Type when 204
+  * Fixed `res.send()` 204. Closes #419
+  * Fixed multiple _Set-Cookie_ headers via `res.header()`. Closes #402
+  * Fixed bug messing with error handlers when `listenFD()` is called instead of `listen()`. [thanks guillermo]
+
+
+1.0.0rc2 / 2010-08-17
+==================
+
+  * Added `app.register()` for template engine mapping. Closes #390
+  * Added `res.render()` callback support as second argument (no options)
+  * Added callback support to `res.download()`
+  * Added callback support for `res.sendfile()`
+  * Added support for middleware access via `express.middlewareName()` vs `connect.middlewareName()`
+  * Added "partials" setting to docs
+  * Added default expresso tests to `express(1)` generated app. Closes #384
+  * Fixed `res.sendfile()` error handling, defer via `next()`
+  * Fixed `res.render()` callback when a layout is used [thanks guillermo]
+  * Fixed; `make install` creating ~/.node_libraries when not present
+  * Fixed issue preventing error handlers from being defined anywhere. Closes #387
+
+1.0.0rc / 2010-07-28
+==================
+
+  * Added mounted hook. Closes #369
+  * Added connect dependency to _package.json_
+
+  * Removed "reload views" setting and support code
+    development env never caches, production always caches.
+
+  * Removed _param_ in route callbacks, signature is now
+    simply (req, res, next), previously (req, res, params, next).
+    Use _req.params_ for path captures, _req.query_ for GET params.
+
+  * Fixed "home" setting
+  * Fixed middleware/router precedence issue. Closes #366
+  * Fixed; _configure()_ callbacks called immediately. Closes #368
+
+1.0.0beta2 / 2010-07-23
+==================
+
+  * Added more examples
+  * Added; exporting `Server` constructor
+  * Added `Server#helpers()` for view locals
+  * Added `Server#dynamicHelpers()` for dynamic view locals. Closes #349
+  * Added support for absolute view paths
+  * Added; _home_ setting defaults to `Server#route` for mounted apps. Closes #363
+  * Added Guillermo Rauch to the contributor list
+  * Added support for "as" for non-collection partials. Closes #341
+  * Fixed _install.sh_, ensuring _~/.node_libraries_ exists. Closes #362 [thanks jf]
+  * Fixed `res.render()` exceptions, now passed to `next()` when no callback is given [thanks guillermo]
+  * Fixed instanceof `Array` checks, now `Array.isArray()`
+  * Fixed express(1) expansion of public dirs. Closes #348
+  * Fixed middleware precedence. Closes #345
+  * Fixed view watcher, now async [thanks aheckmann]
+
+1.0.0beta / 2010-07-15
+==================
+
+  * Re-write
+    - much faster
+    - much lighter
+    - Check [ExpressJS.com](http://expressjs.com) for migration guide and updated docs
+
+0.14.0 / 2010-06-15
+==================
+
+  * Utilize relative requires
+  * Added Static bufferSize option [aheckmann]
+  * Fixed caching of view and partial subdirectories [aheckmann]
+  * Fixed mime.type() comments now that ".ext" is not supported
+  * Updated haml submodule
+  * Updated class submodule
+  * Removed bin/express
+
+0.13.0 / 2010-06-01
+==================
+
+  * Added node v0.1.97 compatibility
+  * Added support for deleting cookies via Request#cookie('key', null)
+  * Updated haml submodule
+  * Fixed not-found page, now using charset utf-8
+  * Fixed show-exceptions page, now using charset utf-8
+  * Fixed view support due to fs.readFile Buffers
+  * Changed; mime.type() no longer accepts ".type" due to node extname() changes
+
+0.12.0 / 2010-05-22
+==================
+
+  * Added node v0.1.96 compatibility
+  * Added view `helpers` export which act as additional local variables
+  * Updated haml submodule
+  * Changed ETag; removed inode, modified time only
+  * Fixed LF to CRLF for setting multiple cookies
+  * Fixed cookie compilation; values are now urlencoded
+  * Fixed cookies parsing; accepts quoted values and url escaped cookies
+
+0.11.0 / 2010-05-06
+==================
+
+  * Added support for layouts using different engines
+    - this.render('page.html.haml', { layout: 'super-cool-layout.html.ejs' })
+    - this.render('page.html.haml', { layout: 'foo' }) // assumes 'foo.html.haml'
+    - this.render('page.html.haml', { layout: false }) // no layout
+  * Updated ext submodule
+  * Updated haml submodule
+  * Fixed EJS partial support by passing along the context. Issue #307
+
+0.10.1 / 2010-05-03
+==================
+
+  * Fixed binary uploads.
+
+0.10.0 / 2010-04-30
+==================
+
+  * Added charset support via Request#charset (automatically assigned to 'UTF-8' when respond()'s
+    encoding is set to 'utf8' or 'utf-8').
+  * Added "encoding" option to Request#render(). Closes #299
+  * Added "dump exceptions" setting, which is enabled by default.
+  * Added simple ejs template engine support
+  * Added error response support for text/plain, application/json. Closes #297
+  * Added callback function param to Request#error()
+  * Added Request#sendHead()
+  * Added Request#stream()
+  * Added support for Request#respond(304, null) for empty response bodies
+  * Added ETag support to Request#sendfile()
+  * Added options to Request#sendfile(), passed to fs.createReadStream()
+  * Added filename arg to Request#download()
+  * Performance enhanced due to pre-reversing plugins so that plugins.reverse() is not called on each request
+  * Performance enhanced by preventing several calls to toLowerCase() in Router#match()
+  * Changed; Request#sendfile() now streams
+  * Changed; Renamed Request#halt() to Request#respond(). Closes #289
+  * Changed; Using sys.inspect() instead of JSON.encode() for error output
+  * Changed; run() returns the http.Server instance. Closes #298
+  * Changed; Defaulting Server#host to null (INADDR_ANY)
+  * Changed; Logger "common" format scale of 0.4f
+  * Removed Logger "request" format
+  * Fixed; Catching ENOENT in view caching, preventing error when "views/partials" is not found
+  * Fixed several issues with http client
+  * Fixed Logger Content-Length output
+  * Fixed bug preventing Opera from retaining the generated session id. Closes #292
+
+0.9.0 / 2010-04-14
+==================
+
+  * Added DSL level error() route support
+  * Added DSL level notFound() route support
+  * Added Request#error()
+  * Added Request#notFound()
+  * Added Request#render() callback function. Closes #258
+  * Added "max upload size" setting
+  * Added "magic" variables to collection partials (\_\_index\_\_, \_\_length\_\_, \_\_isFirst\_\_, \_\_isLast\_\_). Closes #254
+  * Added [haml.js](http://github.com/visionmedia/haml.js) submodule; removed haml-js
+  * Added callback function support to Request#halt() as 3rd/4th arg
+  * Added preprocessing of route param wildcards using param(). Closes #251
+  * Added view partial support (with collections etc.)
+  * Fixed bug preventing falsey params (such as ?page=0). Closes #286
+  * Fixed setting of multiple cookies. Closes #199
+  * Changed; view naming convention is now NAME.TYPE.ENGINE (for example page.html.haml)
+  * Changed; session cookie is now httpOnly
+  * Changed; Request is no longer global
+  * Changed; Event is no longer global
+  * Changed; "sys" module is no longer global
+  * Changed; moved Request#download to Static plugin where it belongs
+  * Changed; Request instance created before body parsing. Closes #262
+  * Changed; Pre-caching views in memory when "cache view contents" is enabled. Closes #253
+  * Changed; Pre-caching view partials in memory when "cache view partials" is enabled
+  * Updated support to node --version 0.1.90
+  * Updated dependencies
+  * Removed set("session cookie") in favour of use(Session, { cookie: { ... }})
+  * Removed utils.mixin(); use Object#mergeDeep()
+
+0.8.0 / 2010-03-19
+==================
+
+  * Added coffeescript example app. Closes #242
+  * Changed; cache api now async friendly. Closes #240
+  * Removed deprecated 'express/static' support. Use 'express/plugins/static'
+
+0.7.6 / 2010-03-19
+==================
+
+  * Added Request#isXHR. Closes #229
+  * Added `make install` (for the executable)
+  * Added `express` executable for setting up simple app templates
+  * Added "GET /public/*" to Static plugin, defaulting to <root>/public
+  * Added Static plugin
+  * Fixed; Request#render() only calls cache.get() once
+  * Fixed; Namespacing View caches with "view:"
+  * Fixed; Namespacing Static caches with "static:"
+  * Fixed; Both example apps now use the Static plugin
+  * Fixed set("views"). Closes #239
+  * Fixed missing space for combined log format
+  * Deprecated Request#sendfile() and 'express/static'
+  * Removed Server#running
+
+0.7.5 / 2010-03-16
+==================
+
+  * Added Request#flash() support without args, now returns all flashes
+  * Updated ext submodule
+
+0.7.4 / 2010-03-16
+==================
+
+  * Fixed session reaper
+  * Changed; class.js replacing js-oo Class implementation (quite a bit faster, no browser cruft)
+
+0.7.3 / 2010-03-16
+==================
+
+  * Added package.json
+  * Fixed requiring of haml / sass due to kiwi removal
+
+0.7.2 / 2010-03-16
+==================
+
+  * Fixed GIT submodules (HAH!)
+
+0.7.1 / 2010-03-16
+==================
+
+  * Changed; Express now using submodules again until a PM is adopted
+  * Changed; chat example using millisecond conversions from ext
+
+0.7.0 / 2010-03-15
+==================
+
+  * Added Request#pass() support (finds the next matching route, or the given path)
+  * Added Logger plugin (default "common" format replaces CommonLogger)
+  * Removed Profiler plugin
+  * Removed CommonLogger plugin
+
+0.6.0 / 2010-03-11
+==================
+
+  * Added seed.yml for kiwi package management support
+  * Added HTTP client query string support when method is GET. Closes #205
+
+  * Added support for arbitrary view engines.
+    For example "foo.engine.html" will now require('engine'),
+    the exports from this module are cached after the first require().
+
+  * Added async plugin support
+
+  * Removed usage of RESTful route funcs as http client
+    get() etc, use http.get() and friends
+
+  * Removed custom exceptions
+
+0.5.0 / 2010-03-10
+==================
+
+  * Added ext dependency (library of js extensions)
+  * Removed extname() / basename() utils. Use path module
+  * Removed toArray() util. Use arguments.values
+  * Removed escapeRegexp() util. Use RegExp.escape()
+  * Removed process.mixin() dependency. Use utils.mixin()
+  * Removed Collection
+  * Removed ElementCollection
+  * Shameless self promotion of ebook "Advanced JavaScript" (http://dev-mag.com)  ;)
+
+0.4.0 / 2010-02-11
+==================
+
+  * Added flash() example to sample upload app
+  * Added high level restful http client module (express/http)
+  * Changed; RESTful route functions double as HTTP clients. Closes #69
+  * Changed; throwing error when routes are added at runtime
+  * Changed; defaulting render() context to the current Request. Closes #197
+  * Updated haml submodule
+
+0.3.0 / 2010-02-11
+==================
+
+  * Updated haml / sass submodules. Closes #200
+  * Added flash message support. Closes #64
+  * Added accepts() now allows multiple args. fixes #117
+  * Added support for plugins to halt. Closes #189
+  * Added alternate layout support. Closes #119
+  * Removed Route#run(). Closes #188
+  * Fixed broken specs due to use(Cookie) missing
+
+0.2.1 / 2010-02-05
+==================
+
+  * Added "plot" format option for Profiler (for gnuplot processing)
+  * Added request number to Profiler plugin
+  * Fixed binary encoding for multipart file uploads, was previously defaulting to UTF8
+  * Fixed issue with routes not firing when not files are present. Closes #184
+  * Fixed process.Promise -> events.Promise
+
+0.2.0 / 2010-02-03
+==================
+
+  * Added parseParam() support for name[] etc. (allows for file inputs with "multiple" attr) Closes #180
+  * Added Both Cache and Session option "reapInterval" may be "reapEvery". Closes #174
+  * Added expiration support to cache api with reaper. Closes #133
+  * Added cache Store.Memory#reap()
+  * Added Cache; cache api now uses first class Cache instances
+  * Added abstract session Store. Closes #172
+  * Changed; cache Memory.Store#get() utilizing Collection
+  * Renamed MemoryStore -> Store.Memory
+  * Fixed use() of the same plugin several time will always use latest options. Closes #176
+
+0.1.0 / 2010-02-03
+==================
+
+  * Changed; Hooks (before / after) pass request as arg as well as evaluated in their context
+  * Updated node support to 0.1.27 Closes #169
+  * Updated dirname(__filename) -> __dirname
+  * Updated libxmljs support to v0.2.0
+  * Added session support with memory store / reaping
+  * Added quick uid() helper
+  * Added multi-part upload support
+  * Added Sass.js support / submodule
+  * Added production env caching view contents and static files
+  * Added static file caching. Closes #136
+  * Added cache plugin with memory stores
+  * Added support to StaticFile so that it works with non-textual files.
+  * Removed dirname() helper
+  * Removed several globals (now their modules must be required)
+
+0.0.2 / 2010-01-10
+==================
+
+  * Added view benchmarks; currently haml vs ejs
+  * Added Request#attachment() specs. Closes #116
+  * Added use of node's parseQuery() util. Closes #123
+  * Added `make init` for submodules
+  * Updated Haml
+  * Updated sample chat app to show messages on load
+  * Updated libxmljs parseString -> parseHtmlString
+  * Fixed `make init` to work with older versions of git
+  * Fixed specs can now run independent specs for those who can't build deps. Closes #127
+  * Fixed issues introduced by the node url module changes. Closes 126.
+  * Fixed two assertions failing due to Collection#keys() returning strings
+  * Fixed faulty Collection#toArray() spec due to keys() returning strings
+  * Fixed `make test` now builds libxmljs.node before testing
+
+0.0.1 / 2010-01-03
+==================
+
+  * Initial release
diff --git a/server/node_modules/express/LICENSE b/server/node_modules/express/LICENSE
new file mode 100644
index 0000000..aa927e4
--- /dev/null
+++ b/server/node_modules/express/LICENSE
@@ -0,0 +1,24 @@
+(The MIT License)
+
+Copyright (c) 2009-2014 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2013-2014 Roman Shtylman <shtylman+expressjs@gmail.com>
+Copyright (c) 2014-2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/express/Readme.md b/server/node_modules/express/Readme.md
new file mode 100644
index 0000000..bc108d5
--- /dev/null
+++ b/server/node_modules/express/Readme.md
@@ -0,0 +1,260 @@
+[![Express Logo](https://i.cloudup.com/zfY6lL7eFa-3000x3000.png)](http://expressjs.com/)
+
+**Fast, unopinionated, minimalist web framework for [Node.js](http://nodejs.org).**
+
+**This project has a [Code of Conduct][].**
+
+## Table of contents
+
+* [Installation](#Installation)
+* [Features](#Features)
+* [Docs & Community](#docs--community)
+* [Quick Start](#Quick-Start)
+* [Running Tests](#Running-Tests)
+* [Philosophy](#Philosophy)
+* [Examples](#Examples)
+* [Contributing to Express](#Contributing)
+* [TC (Technical Committee)](#tc-technical-committee)
+* [Triagers](#triagers)
+* [License](#license)
+
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Install Size][npm-install-size-image]][npm-install-size-url]
+[![NPM Downloads][npm-downloads-image]][npm-downloads-url]
+[![OpenSSF Scorecard Badge][ossf-scorecard-badge]][ossf-scorecard-visualizer]
+
+
+```js
+const express = require('express')
+const app = express()
+
+app.get('/', function (req, res) {
+  res.send('Hello World')
+})
+
+app.listen(3000)
+```
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/).
+
+Before installing, [download and install Node.js](https://nodejs.org/en/download/).
+Node.js 0.10 or higher is required.
+
+If this is a brand new project, make sure to create a `package.json` first with
+the [`npm init` command](https://docs.npmjs.com/creating-a-package-json-file).
+
+Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```console
+$ npm install express
+```
+
+Follow [our installing guide](http://expressjs.com/en/starter/installing.html)
+for more information.
+
+## Features
+
+  * Robust routing
+  * Focus on high performance
+  * Super-high test coverage
+  * HTTP helpers (redirection, caching, etc)
+  * View system supporting 14+ template engines
+  * Content negotiation
+  * Executable for generating applications quickly
+
+## Docs & Community
+
+  * [Website and Documentation](http://expressjs.com/) - [[website repo](https://github.com/expressjs/expressjs.com)]
+  * [#express](https://web.libera.chat/#express) on [Libera Chat](https://libera.chat) IRC
+  * [GitHub Organization](https://github.com/expressjs) for Official Middleware & Modules
+  * Visit the [Wiki](https://github.com/expressjs/express/wiki)
+  * [Google Group](https://groups.google.com/group/express-js) for discussion
+  * [Gitter](https://gitter.im/expressjs/express) for support and discussion
+
+**PROTIP** Be sure to read [Migrating from 3.x to 4.x](https://github.com/expressjs/express/wiki/Migrating-from-3.x-to-4.x) as well as [New features in 4.x](https://github.com/expressjs/express/wiki/New-features-in-4.x).
+
+## Quick Start
+
+  The quickest way to get started with express is to utilize the executable [`express(1)`](https://github.com/expressjs/generator) to generate an application as shown below:
+
+  Install the executable. The executable's major version will match Express's:
+
+```console
+$ npm install -g express-generator@4
+```
+
+  Create the app:
+
+```console
+$ express /tmp/foo && cd /tmp/foo
+```
+
+  Install dependencies:
+
+```console
+$ npm install
+```
+
+  Start the server:
+
+```console
+$ npm start
+```
+
+  View the website at: http://localhost:3000
+
+## Philosophy
+
+  The Express philosophy is to provide small, robust tooling for HTTP servers, making
+  it a great solution for single page applications, websites, hybrids, or public
+  HTTP APIs.
+
+  Express does not force you to use any specific ORM or template engine. With support for over
+  14 template engines via [Consolidate.js](https://github.com/tj/consolidate.js),
+  you can quickly craft your perfect framework.
+
+## Examples
+
+  To view the examples, clone the Express repo and install the dependencies:
+
+```console
+$ git clone https://github.com/expressjs/express.git --depth 1
+$ cd express
+$ npm install
+```
+
+  Then run whichever example you want:
+
+```console
+$ node examples/content-negotiation
+```
+
+## Contributing
+
+  [![Linux Build][github-actions-ci-image]][github-actions-ci-url]
+  [![Windows Build][appveyor-image]][appveyor-url]
+  [![Test Coverage][coveralls-image]][coveralls-url]
+
+The Express.js project welcomes all constructive contributions. Contributions take many forms,
+from code for bug fixes and enhancements, to additions and fixes to documentation, additional
+tests, triaging incoming pull requests and issues, and more!
+
+See the [Contributing Guide](Contributing.md) for more technical details on contributing.
+
+### Security Issues
+
+If you discover a security vulnerability in Express, please see [Security Policies and Procedures](Security.md).
+
+### Running Tests
+
+To run the test suite, first install the dependencies, then run `npm test`:
+
+```console
+$ npm install
+$ npm test
+```
+
+## People
+
+The original author of Express is [TJ Holowaychuk](https://github.com/tj)
+
+[List of all contributors](https://github.com/expressjs/express/graphs/contributors)
+
+### TC (Technical Committee)
+
+* [UlisesGascon](https://github.com/UlisesGascon) - **Ulises Gascón** (he/him)
+* [jonchurch](https://github.com/jonchurch) - **Jon Church**
+* [wesleytodd](https://github.com/wesleytodd) - **Wes Todd**
+* [LinusU](https://github.com/LinusU) - **Linus Unnebäck**
+* [blakeembrey](https://github.com/blakeembrey) - **Blake Embrey**
+* [sheplu](https://github.com/sheplu) - **Jean Burellier**
+* [crandmck](https://github.com/crandmck) - **Rand McKinney**
+* [ctcpip](https://github.com/ctcpip) - **Chris de Almeida**
+
+<details>
+<summary>TC emeriti members</summary>
+
+#### TC emeriti members
+
+  * [dougwilson](https://github.com/dougwilson) - **Douglas Wilson**
+  * [hacksparrow](https://github.com/hacksparrow) - **Hage Yaapa**
+  * [jonathanong](https://github.com/jonathanong) - **jongleberry**
+  * [niftylettuce](https://github.com/niftylettuce) - **niftylettuce**
+  * [troygoode](https://github.com/troygoode) - **Troy Goode**
+</details>
+
+
+### Triagers
+
+* [aravindvnair99](https://github.com/aravindvnair99) - **Aravind Nair**
+* [carpasse](https://github.com/carpasse) - **Carlos Serrano**
+* [CBID2](https://github.com/CBID2) - **Christine Belzie**
+* [enyoghasim](https://github.com/enyoghasim) - **David Enyoghasim**
+* [UlisesGascon](https://github.com/UlisesGascon) - **Ulises Gascón** (he/him)
+* [mertcanaltin](https://github.com/mertcanaltin) - **Mert Can Altin**
+* [0ss](https://github.com/0ss) - **Salah**
+* [import-brain](https://github.com/import-brain) - **Eric Cheng** (he/him)
+* [3imed-jaberi](https://github.com/3imed-jaberi) - **Imed Jaberi**
+* [dakshkhetan](https://github.com/dakshkhetan) - **Daksh Khetan** (he/him)
+* [lucasraziel](https://github.com/lucasraziel) - **Lucas Soares Do Rego**
+* [IamLizu](https://github.com/IamLizu) - **S M Mahmudul Hasan** (he/him)
+* [Sushmeet](https://github.com/Sushmeet) - **Sushmeet Sunger**
+
+<details>
+<summary>Triagers emeriti members</summary>
+
+#### Emeritus Triagers
+
+  * [AuggieH](https://github.com/AuggieH) - **Auggie Hudak**
+  * [G-Rath](https://github.com/G-Rath) - **Gareth Jones**
+  * [MohammadXroid](https://github.com/MohammadXroid) - **Mohammad Ayashi**
+  * [NawafSwe](https://github.com/NawafSwe) - **Nawaf Alsharqi**
+  * [NotMoni](https://github.com/NotMoni) - **Moni**
+  * [VigneshMurugan](https://github.com/VigneshMurugan) - **Vignesh Murugan**
+  * [davidmashe](https://github.com/davidmashe) - **David Ashe**
+  * [digitaIfabric](https://github.com/digitaIfabric) - **David**
+  * [e-l-i-s-e](https://github.com/e-l-i-s-e) - **Elise Bonner**
+  * [fed135](https://github.com/fed135) - **Frederic Charette**
+  * [firmanJS](https://github.com/firmanJS) - **Firman Abdul Hakim**
+  * [getspooky](https://github.com/getspooky) - **Yasser Ameur**
+  * [ghinks](https://github.com/ghinks) - **Glenn**
+  * [ghousemohamed](https://github.com/ghousemohamed) - **Ghouse Mohamed**
+  * [gireeshpunathil](https://github.com/gireeshpunathil) - **Gireesh Punathil**
+  * [jake32321](https://github.com/jake32321) - **Jake Reed**
+  * [jonchurch](https://github.com/jonchurch) - **Jon Church**
+  * [lekanikotun](https://github.com/lekanikotun) - **Troy Goode**
+  * [marsonya](https://github.com/marsonya) - **Lekan Ikotun**
+  * [mastermatt](https://github.com/mastermatt) - **Matt R. Wilson**
+  * [maxakuru](https://github.com/maxakuru) - **Max Edell**
+  * [mlrawlings](https://github.com/mlrawlings) - **Michael Rawlings**
+  * [rodion-arr](https://github.com/rodion-arr) - **Rodion Abdurakhimov**
+  * [sheplu](https://github.com/sheplu) - **Jean Burellier**
+  * [tarunyadav1](https://github.com/tarunyadav1) - **Tarun yadav**
+  * [tunniclm](https://github.com/tunniclm) - **Mike Tunnicliffe**
+</details>
+
+
+## License
+
+  [MIT](LICENSE)
+
+[appveyor-image]: https://badgen.net/appveyor/ci/dougwilson/express/master?label=windows
+[appveyor-url]: https://ci.appveyor.com/project/dougwilson/express
+[coveralls-image]: https://badgen.net/coveralls/c/github/expressjs/express/master
+[coveralls-url]: https://coveralls.io/r/expressjs/express?branch=master
+[github-actions-ci-image]: https://badgen.net/github/checks/expressjs/express/master?label=linux
+[github-actions-ci-url]: https://github.com/expressjs/express/actions/workflows/ci.yml
+[npm-downloads-image]: https://badgen.net/npm/dm/express
+[npm-downloads-url]: https://npmcharts.com/compare/express?minimal=true
+[npm-install-size-image]: https://badgen.net/packagephobia/install/express
+[npm-install-size-url]: https://packagephobia.com/result?p=express
+[npm-url]: https://npmjs.org/package/express
+[npm-version-image]: https://badgen.net/npm/v/express
+[ossf-scorecard-badge]: https://api.scorecard.dev/projects/github.com/expressjs/express/badge
+[ossf-scorecard-visualizer]: https://ossf.github.io/scorecard-visualizer/#/projects/github.com/expressjs/express
+[Code of Conduct]: https://github.com/expressjs/express/blob/master/Code-Of-Conduct.md
diff --git a/server/node_modules/express/index.js b/server/node_modules/express/index.js
new file mode 100644
index 0000000..d219b0c
--- /dev/null
+++ b/server/node_modules/express/index.js
@@ -0,0 +1,11 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+module.exports = require('./lib/express');
diff --git a/server/node_modules/express/lib/application.js b/server/node_modules/express/lib/application.js
new file mode 100644
index 0000000..ebb30b5
--- /dev/null
+++ b/server/node_modules/express/lib/application.js
@@ -0,0 +1,661 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var finalhandler = require('finalhandler');
+var Router = require('./router');
+var methods = require('methods');
+var middleware = require('./middleware/init');
+var query = require('./middleware/query');
+var debug = require('debug')('express:application');
+var View = require('./view');
+var http = require('http');
+var compileETag = require('./utils').compileETag;
+var compileQueryParser = require('./utils').compileQueryParser;
+var compileTrust = require('./utils').compileTrust;
+var deprecate = require('depd')('express');
+var flatten = require('array-flatten');
+var merge = require('utils-merge');
+var resolve = require('path').resolve;
+var setPrototypeOf = require('setprototypeof')
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var hasOwnProperty = Object.prototype.hasOwnProperty
+var slice = Array.prototype.slice;
+
+/**
+ * Application prototype.
+ */
+
+var app = exports = module.exports = {};
+
+/**
+ * Variable for trust proxy inheritance back-compat
+ * @private
+ */
+
+var trustProxyDefaultSymbol = '@@symbol:trust_proxy_default';
+
+/**
+ * Initialize the server.
+ *
+ *   - setup default configuration
+ *   - setup default middleware
+ *   - setup route reflection methods
+ *
+ * @private
+ */
+
+app.init = function init() {
+  this.cache = {};
+  this.engines = {};
+  this.settings = {};
+
+  this.defaultConfiguration();
+};
+
+/**
+ * Initialize application configuration.
+ * @private
+ */
+
+app.defaultConfiguration = function defaultConfiguration() {
+  var env = process.env.NODE_ENV || 'development';
+
+  // default settings
+  this.enable('x-powered-by');
+  this.set('etag', 'weak');
+  this.set('env', env);
+  this.set('query parser', 'extended');
+  this.set('subdomain offset', 2);
+  this.set('trust proxy', false);
+
+  // trust proxy inherit back-compat
+  Object.defineProperty(this.settings, trustProxyDefaultSymbol, {
+    configurable: true,
+    value: true
+  });
+
+  debug('booting in %s mode', env);
+
+  this.on('mount', function onmount(parent) {
+    // inherit trust proxy
+    if (this.settings[trustProxyDefaultSymbol] === true
+      && typeof parent.settings['trust proxy fn'] === 'function') {
+      delete this.settings['trust proxy'];
+      delete this.settings['trust proxy fn'];
+    }
+
+    // inherit protos
+    setPrototypeOf(this.request, parent.request)
+    setPrototypeOf(this.response, parent.response)
+    setPrototypeOf(this.engines, parent.engines)
+    setPrototypeOf(this.settings, parent.settings)
+  });
+
+  // setup locals
+  this.locals = Object.create(null);
+
+  // top-most app is mounted at /
+  this.mountpath = '/';
+
+  // default locals
+  this.locals.settings = this.settings;
+
+  // default configuration
+  this.set('view', View);
+  this.set('views', resolve('views'));
+  this.set('jsonp callback name', 'callback');
+
+  if (env === 'production') {
+    this.enable('view cache');
+  }
+
+  Object.defineProperty(this, 'router', {
+    get: function() {
+      throw new Error('\'app.router\' is deprecated!\nPlease see the 3.x to 4.x migration guide for details on how to update your app.');
+    }
+  });
+};
+
+/**
+ * lazily adds the base router if it has not yet been added.
+ *
+ * We cannot add the base router in the defaultConfiguration because
+ * it reads app settings which might be set after that has run.
+ *
+ * @private
+ */
+app.lazyrouter = function lazyrouter() {
+  if (!this._router) {
+    this._router = new Router({
+      caseSensitive: this.enabled('case sensitive routing'),
+      strict: this.enabled('strict routing')
+    });
+
+    this._router.use(query(this.get('query parser fn')));
+    this._router.use(middleware.init(this));
+  }
+};
+
+/**
+ * Dispatch a req, res pair into the application. Starts pipeline processing.
+ *
+ * If no callback is provided, then default error handlers will respond
+ * in the event of an error bubbling through the stack.
+ *
+ * @private
+ */
+
+app.handle = function handle(req, res, callback) {
+  var router = this._router;
+
+  // final handler
+  var done = callback || finalhandler(req, res, {
+    env: this.get('env'),
+    onerror: logerror.bind(this)
+  });
+
+  // no routes
+  if (!router) {
+    debug('no routes defined on app');
+    done();
+    return;
+  }
+
+  router.handle(req, res, done);
+};
+
+/**
+ * Proxy `Router#use()` to add middleware to the app router.
+ * See Router#use() documentation for details.
+ *
+ * If the _fn_ parameter is an express app, then it will be
+ * mounted at the _route_ specified.
+ *
+ * @public
+ */
+
+app.use = function use(fn) {
+  var offset = 0;
+  var path = '/';
+
+  // default path to '/'
+  // disambiguate app.use([fn])
+  if (typeof fn !== 'function') {
+    var arg = fn;
+
+    while (Array.isArray(arg) && arg.length !== 0) {
+      arg = arg[0];
+    }
+
+    // first arg is the path
+    if (typeof arg !== 'function') {
+      offset = 1;
+      path = fn;
+    }
+  }
+
+  var fns = flatten(slice.call(arguments, offset));
+
+  if (fns.length === 0) {
+    throw new TypeError('app.use() requires a middleware function')
+  }
+
+  // setup router
+  this.lazyrouter();
+  var router = this._router;
+
+  fns.forEach(function (fn) {
+    // non-express app
+    if (!fn || !fn.handle || !fn.set) {
+      return router.use(path, fn);
+    }
+
+    debug('.use app under %s', path);
+    fn.mountpath = path;
+    fn.parent = this;
+
+    // restore .app property on req and res
+    router.use(path, function mounted_app(req, res, next) {
+      var orig = req.app;
+      fn.handle(req, res, function (err) {
+        setPrototypeOf(req, orig.request)
+        setPrototypeOf(res, orig.response)
+        next(err);
+      });
+    });
+
+    // mounted an app
+    fn.emit('mount', this);
+  }, this);
+
+  return this;
+};
+
+/**
+ * Proxy to the app `Router#route()`
+ * Returns a new `Route` instance for the _path_.
+ *
+ * Routes are isolated middleware stacks for specific paths.
+ * See the Route api docs for details.
+ *
+ * @public
+ */
+
+app.route = function route(path) {
+  this.lazyrouter();
+  return this._router.route(path);
+};
+
+/**
+ * Register the given template engine callback `fn`
+ * as `ext`.
+ *
+ * By default will `require()` the engine based on the
+ * file extension. For example if you try to render
+ * a "foo.ejs" file Express will invoke the following internally:
+ *
+ *     app.engine('ejs', require('ejs').__express);
+ *
+ * For engines that do not provide `.__express` out of the box,
+ * or if you wish to "map" a different extension to the template engine
+ * you may use this method. For example mapping the EJS template engine to
+ * ".html" files:
+ *
+ *     app.engine('html', require('ejs').renderFile);
+ *
+ * In this case EJS provides a `.renderFile()` method with
+ * the same signature that Express expects: `(path, options, callback)`,
+ * though note that it aliases this method as `ejs.__express` internally
+ * so if you're using ".ejs" extensions you don't need to do anything.
+ *
+ * Some template engines do not follow this convention, the
+ * [Consolidate.js](https://github.com/tj/consolidate.js)
+ * library was created to map all of node's popular template
+ * engines to follow this convention, thus allowing them to
+ * work seamlessly within Express.
+ *
+ * @param {String} ext
+ * @param {Function} fn
+ * @return {app} for chaining
+ * @public
+ */
+
+app.engine = function engine(ext, fn) {
+  if (typeof fn !== 'function') {
+    throw new Error('callback function required');
+  }
+
+  // get file extension
+  var extension = ext[0] !== '.'
+    ? '.' + ext
+    : ext;
+
+  // store engine
+  this.engines[extension] = fn;
+
+  return this;
+};
+
+/**
+ * Proxy to `Router#param()` with one added api feature. The _name_ parameter
+ * can be an array of names.
+ *
+ * See the Router#param() docs for more details.
+ *
+ * @param {String|Array} name
+ * @param {Function} fn
+ * @return {app} for chaining
+ * @public
+ */
+
+app.param = function param(name, fn) {
+  this.lazyrouter();
+
+  if (Array.isArray(name)) {
+    for (var i = 0; i < name.length; i++) {
+      this.param(name[i], fn);
+    }
+
+    return this;
+  }
+
+  this._router.param(name, fn);
+
+  return this;
+};
+
+/**
+ * Assign `setting` to `val`, or return `setting`'s value.
+ *
+ *    app.set('foo', 'bar');
+ *    app.set('foo');
+ *    // => "bar"
+ *
+ * Mounted servers inherit their parent server's settings.
+ *
+ * @param {String} setting
+ * @param {*} [val]
+ * @return {Server} for chaining
+ * @public
+ */
+
+app.set = function set(setting, val) {
+  if (arguments.length === 1) {
+    // app.get(setting)
+    var settings = this.settings
+
+    while (settings && settings !== Object.prototype) {
+      if (hasOwnProperty.call(settings, setting)) {
+        return settings[setting]
+      }
+
+      settings = Object.getPrototypeOf(settings)
+    }
+
+    return undefined
+  }
+
+  debug('set "%s" to %o', setting, val);
+
+  // set value
+  this.settings[setting] = val;
+
+  // trigger matched settings
+  switch (setting) {
+    case 'etag':
+      this.set('etag fn', compileETag(val));
+      break;
+    case 'query parser':
+      this.set('query parser fn', compileQueryParser(val));
+      break;
+    case 'trust proxy':
+      this.set('trust proxy fn', compileTrust(val));
+
+      // trust proxy inherit back-compat
+      Object.defineProperty(this.settings, trustProxyDefaultSymbol, {
+        configurable: true,
+        value: false
+      });
+
+      break;
+  }
+
+  return this;
+};
+
+/**
+ * Return the app's absolute pathname
+ * based on the parent(s) that have
+ * mounted it.
+ *
+ * For example if the application was
+ * mounted as "/admin", which itself
+ * was mounted as "/blog" then the
+ * return value would be "/blog/admin".
+ *
+ * @return {String}
+ * @private
+ */
+
+app.path = function path() {
+  return this.parent
+    ? this.parent.path() + this.mountpath
+    : '';
+};
+
+/**
+ * Check if `setting` is enabled (truthy).
+ *
+ *    app.enabled('foo')
+ *    // => false
+ *
+ *    app.enable('foo')
+ *    app.enabled('foo')
+ *    // => true
+ *
+ * @param {String} setting
+ * @return {Boolean}
+ * @public
+ */
+
+app.enabled = function enabled(setting) {
+  return Boolean(this.set(setting));
+};
+
+/**
+ * Check if `setting` is disabled.
+ *
+ *    app.disabled('foo')
+ *    // => true
+ *
+ *    app.enable('foo')
+ *    app.disabled('foo')
+ *    // => false
+ *
+ * @param {String} setting
+ * @return {Boolean}
+ * @public
+ */
+
+app.disabled = function disabled(setting) {
+  return !this.set(setting);
+};
+
+/**
+ * Enable `setting`.
+ *
+ * @param {String} setting
+ * @return {app} for chaining
+ * @public
+ */
+
+app.enable = function enable(setting) {
+  return this.set(setting, true);
+};
+
+/**
+ * Disable `setting`.
+ *
+ * @param {String} setting
+ * @return {app} for chaining
+ * @public
+ */
+
+app.disable = function disable(setting) {
+  return this.set(setting, false);
+};
+
+/**
+ * Delegate `.VERB(...)` calls to `router.VERB(...)`.
+ */
+
+methods.forEach(function(method){
+  app[method] = function(path){
+    if (method === 'get' && arguments.length === 1) {
+      // app.get(setting)
+      return this.set(path);
+    }
+
+    this.lazyrouter();
+
+    var route = this._router.route(path);
+    route[method].apply(route, slice.call(arguments, 1));
+    return this;
+  };
+});
+
+/**
+ * Special-cased "all" method, applying the given route `path`,
+ * middleware, and callback to _every_ HTTP method.
+ *
+ * @param {String} path
+ * @param {Function} ...
+ * @return {app} for chaining
+ * @public
+ */
+
+app.all = function all(path) {
+  this.lazyrouter();
+
+  var route = this._router.route(path);
+  var args = slice.call(arguments, 1);
+
+  for (var i = 0; i < methods.length; i++) {
+    route[methods[i]].apply(route, args);
+  }
+
+  return this;
+};
+
+// del -> delete alias
+
+app.del = deprecate.function(app.delete, 'app.del: Use app.delete instead');
+
+/**
+ * Render the given view `name` name with `options`
+ * and a callback accepting an error and the
+ * rendered template string.
+ *
+ * Example:
+ *
+ *    app.render('email', { name: 'Tobi' }, function(err, html){
+ *      // ...
+ *    })
+ *
+ * @param {String} name
+ * @param {Object|Function} options or fn
+ * @param {Function} callback
+ * @public
+ */
+
+app.render = function render(name, options, callback) {
+  var cache = this.cache;
+  var done = callback;
+  var engines = this.engines;
+  var opts = options;
+  var renderOptions = {};
+  var view;
+
+  // support callback function as second arg
+  if (typeof options === 'function') {
+    done = options;
+    opts = {};
+  }
+
+  // merge app.locals
+  merge(renderOptions, this.locals);
+
+  // merge options._locals
+  if (opts._locals) {
+    merge(renderOptions, opts._locals);
+  }
+
+  // merge options
+  merge(renderOptions, opts);
+
+  // set .cache unless explicitly provided
+  if (renderOptions.cache == null) {
+    renderOptions.cache = this.enabled('view cache');
+  }
+
+  // primed cache
+  if (renderOptions.cache) {
+    view = cache[name];
+  }
+
+  // view
+  if (!view) {
+    var View = this.get('view');
+
+    view = new View(name, {
+      defaultEngine: this.get('view engine'),
+      root: this.get('views'),
+      engines: engines
+    });
+
+    if (!view.path) {
+      var dirs = Array.isArray(view.root) && view.root.length > 1
+        ? 'directories "' + view.root.slice(0, -1).join('", "') + '" or "' + view.root[view.root.length - 1] + '"'
+        : 'directory "' + view.root + '"'
+      var err = new Error('Failed to lookup view "' + name + '" in views ' + dirs);
+      err.view = view;
+      return done(err);
+    }
+
+    // prime the cache
+    if (renderOptions.cache) {
+      cache[name] = view;
+    }
+  }
+
+  // render
+  tryRender(view, renderOptions, done);
+};
+
+/**
+ * Listen for connections.
+ *
+ * A node `http.Server` is returned, with this
+ * application (which is a `Function`) as its
+ * callback. If you wish to create both an HTTP
+ * and HTTPS server you may do so with the "http"
+ * and "https" modules as shown here:
+ *
+ *    var http = require('http')
+ *      , https = require('https')
+ *      , express = require('express')
+ *      , app = express();
+ *
+ *    http.createServer(app).listen(80);
+ *    https.createServer({ ... }, app).listen(443);
+ *
+ * @return {http.Server}
+ * @public
+ */
+
+app.listen = function listen() {
+  var server = http.createServer(this);
+  return server.listen.apply(server, arguments);
+};
+
+/**
+ * Log error using console.error.
+ *
+ * @param {Error} err
+ * @private
+ */
+
+function logerror(err) {
+  /* istanbul ignore next */
+  if (this.get('env') !== 'test') console.error(err.stack || err.toString());
+}
+
+/**
+ * Try rendering a view.
+ * @private
+ */
+
+function tryRender(view, options, callback) {
+  try {
+    view.render(options, callback);
+  } catch (err) {
+    callback(err);
+  }
+}
diff --git a/server/node_modules/express/lib/express.js b/server/node_modules/express/lib/express.js
new file mode 100644
index 0000000..d188a16
--- /dev/null
+++ b/server/node_modules/express/lib/express.js
@@ -0,0 +1,116 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ */
+
+var bodyParser = require('body-parser')
+var EventEmitter = require('events').EventEmitter;
+var mixin = require('merge-descriptors');
+var proto = require('./application');
+var Route = require('./router/route');
+var Router = require('./router');
+var req = require('./request');
+var res = require('./response');
+
+/**
+ * Expose `createApplication()`.
+ */
+
+exports = module.exports = createApplication;
+
+/**
+ * Create an express application.
+ *
+ * @return {Function}
+ * @api public
+ */
+
+function createApplication() {
+  var app = function(req, res, next) {
+    app.handle(req, res, next);
+  };
+
+  mixin(app, EventEmitter.prototype, false);
+  mixin(app, proto, false);
+
+  // expose the prototype that will get set on requests
+  app.request = Object.create(req, {
+    app: { configurable: true, enumerable: true, writable: true, value: app }
+  })
+
+  // expose the prototype that will get set on responses
+  app.response = Object.create(res, {
+    app: { configurable: true, enumerable: true, writable: true, value: app }
+  })
+
+  app.init();
+  return app;
+}
+
+/**
+ * Expose the prototypes.
+ */
+
+exports.application = proto;
+exports.request = req;
+exports.response = res;
+
+/**
+ * Expose constructors.
+ */
+
+exports.Route = Route;
+exports.Router = Router;
+
+/**
+ * Expose middleware
+ */
+
+exports.json = bodyParser.json
+exports.query = require('./middleware/query');
+exports.raw = bodyParser.raw
+exports.static = require('serve-static');
+exports.text = bodyParser.text
+exports.urlencoded = bodyParser.urlencoded
+
+/**
+ * Replace removed middleware with an appropriate error message.
+ */
+
+var removedMiddlewares = [
+  'bodyParser',
+  'compress',
+  'cookieSession',
+  'session',
+  'logger',
+  'cookieParser',
+  'favicon',
+  'responseTime',
+  'errorHandler',
+  'timeout',
+  'methodOverride',
+  'vhost',
+  'csrf',
+  'directory',
+  'limit',
+  'multipart',
+  'staticCache'
+]
+
+removedMiddlewares.forEach(function (name) {
+  Object.defineProperty(exports, name, {
+    get: function () {
+      throw new Error('Most middleware (like ' + name + ') is no longer bundled with Express and must be installed separately. Please see https://github.com/senchalabs/connect#middleware.');
+    },
+    configurable: true
+  });
+});
diff --git a/server/node_modules/express/lib/middleware/init.js b/server/node_modules/express/lib/middleware/init.js
new file mode 100644
index 0000000..dfd0427
--- /dev/null
+++ b/server/node_modules/express/lib/middleware/init.js
@@ -0,0 +1,43 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var setPrototypeOf = require('setprototypeof')
+
+/**
+ * Initialization middleware, exposing the
+ * request and response to each other, as well
+ * as defaulting the X-Powered-By header field.
+ *
+ * @param {Function} app
+ * @return {Function}
+ * @api private
+ */
+
+exports.init = function(app){
+  return function expressInit(req, res, next){
+    if (app.enabled('x-powered-by')) res.setHeader('X-Powered-By', 'Express');
+    req.res = res;
+    res.req = req;
+    req.next = next;
+
+    setPrototypeOf(req, app.request)
+    setPrototypeOf(res, app.response)
+
+    res.locals = res.locals || Object.create(null);
+
+    next();
+  };
+};
+
diff --git a/server/node_modules/express/lib/middleware/query.js b/server/node_modules/express/lib/middleware/query.js
new file mode 100644
index 0000000..7e91669
--- /dev/null
+++ b/server/node_modules/express/lib/middleware/query.js
@@ -0,0 +1,47 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ */
+
+var merge = require('utils-merge')
+var parseUrl = require('parseurl');
+var qs = require('qs');
+
+/**
+ * @param {Object} options
+ * @return {Function}
+ * @api public
+ */
+
+module.exports = function query(options) {
+  var opts = merge({}, options)
+  var queryparse = qs.parse;
+
+  if (typeof options === 'function') {
+    queryparse = options;
+    opts = undefined;
+  }
+
+  if (opts !== undefined && opts.allowPrototypes === undefined) {
+    // back-compat for qs module
+    opts.allowPrototypes = true;
+  }
+
+  return function query(req, res, next){
+    if (!req.query) {
+      var val = parseUrl(req).query;
+      req.query = queryparse(val, opts);
+    }
+
+    next();
+  };
+};
diff --git a/server/node_modules/express/lib/request.js b/server/node_modules/express/lib/request.js
new file mode 100644
index 0000000..3f1eeca
--- /dev/null
+++ b/server/node_modules/express/lib/request.js
@@ -0,0 +1,525 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var accepts = require('accepts');
+var deprecate = require('depd')('express');
+var isIP = require('net').isIP;
+var typeis = require('type-is');
+var http = require('http');
+var fresh = require('fresh');
+var parseRange = require('range-parser');
+var parse = require('parseurl');
+var proxyaddr = require('proxy-addr');
+
+/**
+ * Request prototype.
+ * @public
+ */
+
+var req = Object.create(http.IncomingMessage.prototype)
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = req
+
+/**
+ * Return request header.
+ *
+ * The `Referrer` header field is special-cased,
+ * both `Referrer` and `Referer` are interchangeable.
+ *
+ * Examples:
+ *
+ *     req.get('Content-Type');
+ *     // => "text/plain"
+ *
+ *     req.get('content-type');
+ *     // => "text/plain"
+ *
+ *     req.get('Something');
+ *     // => undefined
+ *
+ * Aliased as `req.header()`.
+ *
+ * @param {String} name
+ * @return {String}
+ * @public
+ */
+
+req.get =
+req.header = function header(name) {
+  if (!name) {
+    throw new TypeError('name argument is required to req.get');
+  }
+
+  if (typeof name !== 'string') {
+    throw new TypeError('name must be a string to req.get');
+  }
+
+  var lc = name.toLowerCase();
+
+  switch (lc) {
+    case 'referer':
+    case 'referrer':
+      return this.headers.referrer
+        || this.headers.referer;
+    default:
+      return this.headers[lc];
+  }
+};
+
+/**
+ * To do: update docs.
+ *
+ * Check if the given `type(s)` is acceptable, returning
+ * the best match when true, otherwise `undefined`, in which
+ * case you should respond with 406 "Not Acceptable".
+ *
+ * The `type` value may be a single MIME type string
+ * such as "application/json", an extension name
+ * such as "json", a comma-delimited list such as "json, html, text/plain",
+ * an argument list such as `"json", "html", "text/plain"`,
+ * or an array `["json", "html", "text/plain"]`. When a list
+ * or array is given, the _best_ match, if any is returned.
+ *
+ * Examples:
+ *
+ *     // Accept: text/html
+ *     req.accepts('html');
+ *     // => "html"
+ *
+ *     // Accept: text/*, application/json
+ *     req.accepts('html');
+ *     // => "html"
+ *     req.accepts('text/html');
+ *     // => "text/html"
+ *     req.accepts('json, text');
+ *     // => "json"
+ *     req.accepts('application/json');
+ *     // => "application/json"
+ *
+ *     // Accept: text/*, application/json
+ *     req.accepts('image/png');
+ *     req.accepts('png');
+ *     // => undefined
+ *
+ *     // Accept: text/*;q=.5, application/json
+ *     req.accepts(['html', 'json']);
+ *     req.accepts('html', 'json');
+ *     req.accepts('html, json');
+ *     // => "json"
+ *
+ * @param {String|Array} type(s)
+ * @return {String|Array|Boolean}
+ * @public
+ */
+
+req.accepts = function(){
+  var accept = accepts(this);
+  return accept.types.apply(accept, arguments);
+};
+
+/**
+ * Check if the given `encoding`s are accepted.
+ *
+ * @param {String} ...encoding
+ * @return {String|Array}
+ * @public
+ */
+
+req.acceptsEncodings = function(){
+  var accept = accepts(this);
+  return accept.encodings.apply(accept, arguments);
+};
+
+req.acceptsEncoding = deprecate.function(req.acceptsEncodings,
+  'req.acceptsEncoding: Use acceptsEncodings instead');
+
+/**
+ * Check if the given `charset`s are acceptable,
+ * otherwise you should respond with 406 "Not Acceptable".
+ *
+ * @param {String} ...charset
+ * @return {String|Array}
+ * @public
+ */
+
+req.acceptsCharsets = function(){
+  var accept = accepts(this);
+  return accept.charsets.apply(accept, arguments);
+};
+
+req.acceptsCharset = deprecate.function(req.acceptsCharsets,
+  'req.acceptsCharset: Use acceptsCharsets instead');
+
+/**
+ * Check if the given `lang`s are acceptable,
+ * otherwise you should respond with 406 "Not Acceptable".
+ *
+ * @param {String} ...lang
+ * @return {String|Array}
+ * @public
+ */
+
+req.acceptsLanguages = function(){
+  var accept = accepts(this);
+  return accept.languages.apply(accept, arguments);
+};
+
+req.acceptsLanguage = deprecate.function(req.acceptsLanguages,
+  'req.acceptsLanguage: Use acceptsLanguages instead');
+
+/**
+ * Parse Range header field, capping to the given `size`.
+ *
+ * Unspecified ranges such as "0-" require knowledge of your resource length. In
+ * the case of a byte range this is of course the total number of bytes. If the
+ * Range header field is not given `undefined` is returned, `-1` when unsatisfiable,
+ * and `-2` when syntactically invalid.
+ *
+ * When ranges are returned, the array has a "type" property which is the type of
+ * range that is required (most commonly, "bytes"). Each array element is an object
+ * with a "start" and "end" property for the portion of the range.
+ *
+ * The "combine" option can be set to `true` and overlapping & adjacent ranges
+ * will be combined into a single range.
+ *
+ * NOTE: remember that ranges are inclusive, so for example "Range: users=0-3"
+ * should respond with 4 users when available, not 3.
+ *
+ * @param {number} size
+ * @param {object} [options]
+ * @param {boolean} [options.combine=false]
+ * @return {number|array}
+ * @public
+ */
+
+req.range = function range(size, options) {
+  var range = this.get('Range');
+  if (!range) return;
+  return parseRange(size, range, options);
+};
+
+/**
+ * Return the value of param `name` when present or `defaultValue`.
+ *
+ *  - Checks route placeholders, ex: _/user/:id_
+ *  - Checks body params, ex: id=12, {"id":12}
+ *  - Checks query string params, ex: ?id=12
+ *
+ * To utilize request bodies, `req.body`
+ * should be an object. This can be done by using
+ * the `bodyParser()` middleware.
+ *
+ * @param {String} name
+ * @param {Mixed} [defaultValue]
+ * @return {String}
+ * @public
+ */
+
+req.param = function param(name, defaultValue) {
+  var params = this.params || {};
+  var body = this.body || {};
+  var query = this.query || {};
+
+  var args = arguments.length === 1
+    ? 'name'
+    : 'name, default';
+  deprecate('req.param(' + args + '): Use req.params, req.body, or req.query instead');
+
+  if (null != params[name] && params.hasOwnProperty(name)) return params[name];
+  if (null != body[name]) return body[name];
+  if (null != query[name]) return query[name];
+
+  return defaultValue;
+};
+
+/**
+ * Check if the incoming request contains the "Content-Type"
+ * header field, and it contains the given mime `type`.
+ *
+ * Examples:
+ *
+ *      // With Content-Type: text/html; charset=utf-8
+ *      req.is('html');
+ *      req.is('text/html');
+ *      req.is('text/*');
+ *      // => true
+ *
+ *      // When Content-Type is application/json
+ *      req.is('json');
+ *      req.is('application/json');
+ *      req.is('application/*');
+ *      // => true
+ *
+ *      req.is('html');
+ *      // => false
+ *
+ * @param {String|Array} types...
+ * @return {String|false|null}
+ * @public
+ */
+
+req.is = function is(types) {
+  var arr = types;
+
+  // support flattened arguments
+  if (!Array.isArray(types)) {
+    arr = new Array(arguments.length);
+    for (var i = 0; i < arr.length; i++) {
+      arr[i] = arguments[i];
+    }
+  }
+
+  return typeis(this, arr);
+};
+
+/**
+ * Return the protocol string "http" or "https"
+ * when requested with TLS. When the "trust proxy"
+ * setting trusts the socket address, the
+ * "X-Forwarded-Proto" header field will be trusted
+ * and used if present.
+ *
+ * If you're running behind a reverse proxy that
+ * supplies https for you this may be enabled.
+ *
+ * @return {String}
+ * @public
+ */
+
+defineGetter(req, 'protocol', function protocol(){
+  var proto = this.connection.encrypted
+    ? 'https'
+    : 'http';
+  var trust = this.app.get('trust proxy fn');
+
+  if (!trust(this.connection.remoteAddress, 0)) {
+    return proto;
+  }
+
+  // Note: X-Forwarded-Proto is normally only ever a
+  //       single value, but this is to be safe.
+  var header = this.get('X-Forwarded-Proto') || proto
+  var index = header.indexOf(',')
+
+  return index !== -1
+    ? header.substring(0, index).trim()
+    : header.trim()
+});
+
+/**
+ * Short-hand for:
+ *
+ *    req.protocol === 'https'
+ *
+ * @return {Boolean}
+ * @public
+ */
+
+defineGetter(req, 'secure', function secure(){
+  return this.protocol === 'https';
+});
+
+/**
+ * Return the remote address from the trusted proxy.
+ *
+ * The is the remote address on the socket unless
+ * "trust proxy" is set.
+ *
+ * @return {String}
+ * @public
+ */
+
+defineGetter(req, 'ip', function ip(){
+  var trust = this.app.get('trust proxy fn');
+  return proxyaddr(this, trust);
+});
+
+/**
+ * When "trust proxy" is set, trusted proxy addresses + client.
+ *
+ * For example if the value were "client, proxy1, proxy2"
+ * you would receive the array `["client", "proxy1", "proxy2"]`
+ * where "proxy2" is the furthest down-stream and "proxy1" and
+ * "proxy2" were trusted.
+ *
+ * @return {Array}
+ * @public
+ */
+
+defineGetter(req, 'ips', function ips() {
+  var trust = this.app.get('trust proxy fn');
+  var addrs = proxyaddr.all(this, trust);
+
+  // reverse the order (to farthest -> closest)
+  // and remove socket address
+  addrs.reverse().pop()
+
+  return addrs
+});
+
+/**
+ * Return subdomains as an array.
+ *
+ * Subdomains are the dot-separated parts of the host before the main domain of
+ * the app. By default, the domain of the app is assumed to be the last two
+ * parts of the host. This can be changed by setting "subdomain offset".
+ *
+ * For example, if the domain is "tobi.ferrets.example.com":
+ * If "subdomain offset" is not set, req.subdomains is `["ferrets", "tobi"]`.
+ * If "subdomain offset" is 3, req.subdomains is `["tobi"]`.
+ *
+ * @return {Array}
+ * @public
+ */
+
+defineGetter(req, 'subdomains', function subdomains() {
+  var hostname = this.hostname;
+
+  if (!hostname) return [];
+
+  var offset = this.app.get('subdomain offset');
+  var subdomains = !isIP(hostname)
+    ? hostname.split('.').reverse()
+    : [hostname];
+
+  return subdomains.slice(offset);
+});
+
+/**
+ * Short-hand for `url.parse(req.url).pathname`.
+ *
+ * @return {String}
+ * @public
+ */
+
+defineGetter(req, 'path', function path() {
+  return parse(this).pathname;
+});
+
+/**
+ * Parse the "Host" header field to a hostname.
+ *
+ * When the "trust proxy" setting trusts the socket
+ * address, the "X-Forwarded-Host" header field will
+ * be trusted.
+ *
+ * @return {String}
+ * @public
+ */
+
+defineGetter(req, 'hostname', function hostname(){
+  var trust = this.app.get('trust proxy fn');
+  var host = this.get('X-Forwarded-Host');
+
+  if (!host || !trust(this.connection.remoteAddress, 0)) {
+    host = this.get('Host');
+  } else if (host.indexOf(',') !== -1) {
+    // Note: X-Forwarded-Host is normally only ever a
+    //       single value, but this is to be safe.
+    host = host.substring(0, host.indexOf(',')).trimRight()
+  }
+
+  if (!host) return;
+
+  // IPv6 literal support
+  var offset = host[0] === '['
+    ? host.indexOf(']') + 1
+    : 0;
+  var index = host.indexOf(':', offset);
+
+  return index !== -1
+    ? host.substring(0, index)
+    : host;
+});
+
+// TODO: change req.host to return host in next major
+
+defineGetter(req, 'host', deprecate.function(function host(){
+  return this.hostname;
+}, 'req.host: Use req.hostname instead'));
+
+/**
+ * Check if the request is fresh, aka
+ * Last-Modified and/or the ETag
+ * still match.
+ *
+ * @return {Boolean}
+ * @public
+ */
+
+defineGetter(req, 'fresh', function(){
+  var method = this.method;
+  var res = this.res
+  var status = res.statusCode
+
+  // GET or HEAD for weak freshness validation only
+  if ('GET' !== method && 'HEAD' !== method) return false;
+
+  // 2xx or 304 as per rfc2616 14.26
+  if ((status >= 200 && status < 300) || 304 === status) {
+    return fresh(this.headers, {
+      'etag': res.get('ETag'),
+      'last-modified': res.get('Last-Modified')
+    })
+  }
+
+  return false;
+});
+
+/**
+ * Check if the request is stale, aka
+ * "Last-Modified" and / or the "ETag" for the
+ * resource has changed.
+ *
+ * @return {Boolean}
+ * @public
+ */
+
+defineGetter(req, 'stale', function stale(){
+  return !this.fresh;
+});
+
+/**
+ * Check if the request was an _XMLHttpRequest_.
+ *
+ * @return {Boolean}
+ * @public
+ */
+
+defineGetter(req, 'xhr', function xhr(){
+  var val = this.get('X-Requested-With') || '';
+  return val.toLowerCase() === 'xmlhttprequest';
+});
+
+/**
+ * Helper function for creating a getter on an object.
+ *
+ * @param {Object} obj
+ * @param {String} name
+ * @param {Function} getter
+ * @private
+ */
+function defineGetter(obj, name, getter) {
+  Object.defineProperty(obj, name, {
+    configurable: true,
+    enumerable: true,
+    get: getter
+  });
+}
diff --git a/server/node_modules/express/lib/response.js b/server/node_modules/express/lib/response.js
new file mode 100644
index 0000000..2b654f4
--- /dev/null
+++ b/server/node_modules/express/lib/response.js
@@ -0,0 +1,1179 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var Buffer = require('safe-buffer').Buffer
+var contentDisposition = require('content-disposition');
+var createError = require('http-errors')
+var deprecate = require('depd')('express');
+var encodeUrl = require('encodeurl');
+var escapeHtml = require('escape-html');
+var http = require('http');
+var isAbsolute = require('./utils').isAbsolute;
+var onFinished = require('on-finished');
+var path = require('path');
+var statuses = require('statuses')
+var merge = require('utils-merge');
+var sign = require('cookie-signature').sign;
+var normalizeType = require('./utils').normalizeType;
+var normalizeTypes = require('./utils').normalizeTypes;
+var setCharset = require('./utils').setCharset;
+var cookie = require('cookie');
+var send = require('send');
+var extname = path.extname;
+var mime = send.mime;
+var resolve = path.resolve;
+var vary = require('vary');
+
+/**
+ * Response prototype.
+ * @public
+ */
+
+var res = Object.create(http.ServerResponse.prototype)
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = res
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var charsetRegExp = /;\s*charset\s*=/;
+
+/**
+ * Set status `code`.
+ *
+ * @param {Number} code
+ * @return {ServerResponse}
+ * @public
+ */
+
+res.status = function status(code) {
+  if ((typeof code === 'string' || Math.floor(code) !== code) && code > 99 && code < 1000) {
+    deprecate('res.status(' + JSON.stringify(code) + '): use res.status(' + Math.floor(code) + ') instead')
+  }
+  this.statusCode = code;
+  return this;
+};
+
+/**
+ * Set Link header field with the given `links`.
+ *
+ * Examples:
+ *
+ *    res.links({
+ *      next: 'http://api.example.com/users?page=2',
+ *      last: 'http://api.example.com/users?page=5'
+ *    });
+ *
+ * @param {Object} links
+ * @return {ServerResponse}
+ * @public
+ */
+
+res.links = function(links){
+  var link = this.get('Link') || '';
+  if (link) link += ', ';
+  return this.set('Link', link + Object.keys(links).map(function(rel){
+    return '<' + links[rel] + '>; rel="' + rel + '"';
+  }).join(', '));
+};
+
+/**
+ * Send a response.
+ *
+ * Examples:
+ *
+ *     res.send(Buffer.from('wahoo'));
+ *     res.send({ some: 'json' });
+ *     res.send('<p>some html</p>');
+ *
+ * @param {string|number|boolean|object|Buffer} body
+ * @public
+ */
+
+res.send = function send(body) {
+  var chunk = body;
+  var encoding;
+  var req = this.req;
+  var type;
+
+  // settings
+  var app = this.app;
+
+  // allow status / body
+  if (arguments.length === 2) {
+    // res.send(body, status) backwards compat
+    if (typeof arguments[0] !== 'number' && typeof arguments[1] === 'number') {
+      deprecate('res.send(body, status): Use res.status(status).send(body) instead');
+      this.statusCode = arguments[1];
+    } else {
+      deprecate('res.send(status, body): Use res.status(status).send(body) instead');
+      this.statusCode = arguments[0];
+      chunk = arguments[1];
+    }
+  }
+
+  // disambiguate res.send(status) and res.send(status, num)
+  if (typeof chunk === 'number' && arguments.length === 1) {
+    // res.send(status) will set status message as text string
+    if (!this.get('Content-Type')) {
+      this.type('txt');
+    }
+
+    deprecate('res.send(status): Use res.sendStatus(status) instead');
+    this.statusCode = chunk;
+    chunk = statuses.message[chunk]
+  }
+
+  switch (typeof chunk) {
+    // string defaulting to html
+    case 'string':
+      if (!this.get('Content-Type')) {
+        this.type('html');
+      }
+      break;
+    case 'boolean':
+    case 'number':
+    case 'object':
+      if (chunk === null) {
+        chunk = '';
+      } else if (Buffer.isBuffer(chunk)) {
+        if (!this.get('Content-Type')) {
+          this.type('bin');
+        }
+      } else {
+        return this.json(chunk);
+      }
+      break;
+  }
+
+  // write strings in utf-8
+  if (typeof chunk === 'string') {
+    encoding = 'utf8';
+    type = this.get('Content-Type');
+
+    // reflect this in content-type
+    if (typeof type === 'string') {
+      this.set('Content-Type', setCharset(type, 'utf-8'));
+    }
+  }
+
+  // determine if ETag should be generated
+  var etagFn = app.get('etag fn')
+  var generateETag = !this.get('ETag') && typeof etagFn === 'function'
+
+  // populate Content-Length
+  var len
+  if (chunk !== undefined) {
+    if (Buffer.isBuffer(chunk)) {
+      // get length of Buffer
+      len = chunk.length
+    } else if (!generateETag && chunk.length < 1000) {
+      // just calculate length when no ETag + small chunk
+      len = Buffer.byteLength(chunk, encoding)
+    } else {
+      // convert chunk to Buffer and calculate
+      chunk = Buffer.from(chunk, encoding)
+      encoding = undefined;
+      len = chunk.length
+    }
+
+    this.set('Content-Length', len);
+  }
+
+  // populate ETag
+  var etag;
+  if (generateETag && len !== undefined) {
+    if ((etag = etagFn(chunk, encoding))) {
+      this.set('ETag', etag);
+    }
+  }
+
+  // freshness
+  if (req.fresh) this.statusCode = 304;
+
+  // strip irrelevant headers
+  if (204 === this.statusCode || 304 === this.statusCode) {
+    this.removeHeader('Content-Type');
+    this.removeHeader('Content-Length');
+    this.removeHeader('Transfer-Encoding');
+    chunk = '';
+  }
+
+  // alter headers for 205
+  if (this.statusCode === 205) {
+    this.set('Content-Length', '0')
+    this.removeHeader('Transfer-Encoding')
+    chunk = ''
+  }
+
+  if (req.method === 'HEAD') {
+    // skip body for HEAD
+    this.end();
+  } else {
+    // respond
+    this.end(chunk, encoding);
+  }
+
+  return this;
+};
+
+/**
+ * Send JSON response.
+ *
+ * Examples:
+ *
+ *     res.json(null);
+ *     res.json({ user: 'tj' });
+ *
+ * @param {string|number|boolean|object} obj
+ * @public
+ */
+
+res.json = function json(obj) {
+  var val = obj;
+
+  // allow status / body
+  if (arguments.length === 2) {
+    // res.json(body, status) backwards compat
+    if (typeof arguments[1] === 'number') {
+      deprecate('res.json(obj, status): Use res.status(status).json(obj) instead');
+      this.statusCode = arguments[1];
+    } else {
+      deprecate('res.json(status, obj): Use res.status(status).json(obj) instead');
+      this.statusCode = arguments[0];
+      val = arguments[1];
+    }
+  }
+
+  // settings
+  var app = this.app;
+  var escape = app.get('json escape')
+  var replacer = app.get('json replacer');
+  var spaces = app.get('json spaces');
+  var body = stringify(val, replacer, spaces, escape)
+
+  // content-type
+  if (!this.get('Content-Type')) {
+    this.set('Content-Type', 'application/json');
+  }
+
+  return this.send(body);
+};
+
+/**
+ * Send JSON response with JSONP callback support.
+ *
+ * Examples:
+ *
+ *     res.jsonp(null);
+ *     res.jsonp({ user: 'tj' });
+ *
+ * @param {string|number|boolean|object} obj
+ * @public
+ */
+
+res.jsonp = function jsonp(obj) {
+  var val = obj;
+
+  // allow status / body
+  if (arguments.length === 2) {
+    // res.jsonp(body, status) backwards compat
+    if (typeof arguments[1] === 'number') {
+      deprecate('res.jsonp(obj, status): Use res.status(status).jsonp(obj) instead');
+      this.statusCode = arguments[1];
+    } else {
+      deprecate('res.jsonp(status, obj): Use res.status(status).jsonp(obj) instead');
+      this.statusCode = arguments[0];
+      val = arguments[1];
+    }
+  }
+
+  // settings
+  var app = this.app;
+  var escape = app.get('json escape')
+  var replacer = app.get('json replacer');
+  var spaces = app.get('json spaces');
+  var body = stringify(val, replacer, spaces, escape)
+  var callback = this.req.query[app.get('jsonp callback name')];
+
+  // content-type
+  if (!this.get('Content-Type')) {
+    this.set('X-Content-Type-Options', 'nosniff');
+    this.set('Content-Type', 'application/json');
+  }
+
+  // fixup callback
+  if (Array.isArray(callback)) {
+    callback = callback[0];
+  }
+
+  // jsonp
+  if (typeof callback === 'string' && callback.length !== 0) {
+    this.set('X-Content-Type-Options', 'nosniff');
+    this.set('Content-Type', 'text/javascript');
+
+    // restrict callback charset
+    callback = callback.replace(/[^\[\]\w$.]/g, '');
+
+    if (body === undefined) {
+      // empty argument
+      body = ''
+    } else if (typeof body === 'string') {
+      // replace chars not allowed in JavaScript that are in JSON
+      body = body
+        .replace(/\u2028/g, '\\u2028')
+        .replace(/\u2029/g, '\\u2029')
+    }
+
+    // the /**/ is a specific security mitigation for "Rosetta Flash JSONP abuse"
+    // the typeof check is just to reduce client error noise
+    body = '/**/ typeof ' + callback + ' === \'function\' && ' + callback + '(' + body + ');';
+  }
+
+  return this.send(body);
+};
+
+/**
+ * Send given HTTP status code.
+ *
+ * Sets the response status to `statusCode` and the body of the
+ * response to the standard description from node's http.STATUS_CODES
+ * or the statusCode number if no description.
+ *
+ * Examples:
+ *
+ *     res.sendStatus(200);
+ *
+ * @param {number} statusCode
+ * @public
+ */
+
+res.sendStatus = function sendStatus(statusCode) {
+  var body = statuses.message[statusCode] || String(statusCode)
+
+  this.statusCode = statusCode;
+  this.type('txt');
+
+  return this.send(body);
+};
+
+/**
+ * Transfer the file at the given `path`.
+ *
+ * Automatically sets the _Content-Type_ response header field.
+ * The callback `callback(err)` is invoked when the transfer is complete
+ * or when an error occurs. Be sure to check `res.headersSent`
+ * if you wish to attempt responding, as the header and some data
+ * may have already been transferred.
+ *
+ * Options:
+ *
+ *   - `maxAge`   defaulting to 0 (can be string converted by `ms`)
+ *   - `root`     root directory for relative filenames
+ *   - `headers`  object of headers to serve with file
+ *   - `dotfiles` serve dotfiles, defaulting to false; can be `"allow"` to send them
+ *
+ * Other options are passed along to `send`.
+ *
+ * Examples:
+ *
+ *  The following example illustrates how `res.sendFile()` may
+ *  be used as an alternative for the `static()` middleware for
+ *  dynamic situations. The code backing `res.sendFile()` is actually
+ *  the same code, so HTTP cache support etc is identical.
+ *
+ *     app.get('/user/:uid/photos/:file', function(req, res){
+ *       var uid = req.params.uid
+ *         , file = req.params.file;
+ *
+ *       req.user.mayViewFilesFrom(uid, function(yes){
+ *         if (yes) {
+ *           res.sendFile('/uploads/' + uid + '/' + file);
+ *         } else {
+ *           res.send(403, 'Sorry! you cant see that.');
+ *         }
+ *       });
+ *     });
+ *
+ * @public
+ */
+
+res.sendFile = function sendFile(path, options, callback) {
+  var done = callback;
+  var req = this.req;
+  var res = this;
+  var next = req.next;
+  var opts = options || {};
+
+  if (!path) {
+    throw new TypeError('path argument is required to res.sendFile');
+  }
+
+  if (typeof path !== 'string') {
+    throw new TypeError('path must be a string to res.sendFile')
+  }
+
+  // support function as second arg
+  if (typeof options === 'function') {
+    done = options;
+    opts = {};
+  }
+
+  if (!opts.root && !isAbsolute(path)) {
+    throw new TypeError('path must be absolute or specify root to res.sendFile');
+  }
+
+  // create file stream
+  var pathname = encodeURI(path);
+  var file = send(req, pathname, opts);
+
+  // transfer
+  sendfile(res, file, opts, function (err) {
+    if (done) return done(err);
+    if (err && err.code === 'EISDIR') return next();
+
+    // next() all but write errors
+    if (err && err.code !== 'ECONNABORTED' && err.syscall !== 'write') {
+      next(err);
+    }
+  });
+};
+
+/**
+ * Transfer the file at the given `path`.
+ *
+ * Automatically sets the _Content-Type_ response header field.
+ * The callback `callback(err)` is invoked when the transfer is complete
+ * or when an error occurs. Be sure to check `res.headersSent`
+ * if you wish to attempt responding, as the header and some data
+ * may have already been transferred.
+ *
+ * Options:
+ *
+ *   - `maxAge`   defaulting to 0 (can be string converted by `ms`)
+ *   - `root`     root directory for relative filenames
+ *   - `headers`  object of headers to serve with file
+ *   - `dotfiles` serve dotfiles, defaulting to false; can be `"allow"` to send them
+ *
+ * Other options are passed along to `send`.
+ *
+ * Examples:
+ *
+ *  The following example illustrates how `res.sendfile()` may
+ *  be used as an alternative for the `static()` middleware for
+ *  dynamic situations. The code backing `res.sendfile()` is actually
+ *  the same code, so HTTP cache support etc is identical.
+ *
+ *     app.get('/user/:uid/photos/:file', function(req, res){
+ *       var uid = req.params.uid
+ *         , file = req.params.file;
+ *
+ *       req.user.mayViewFilesFrom(uid, function(yes){
+ *         if (yes) {
+ *           res.sendfile('/uploads/' + uid + '/' + file);
+ *         } else {
+ *           res.send(403, 'Sorry! you cant see that.');
+ *         }
+ *       });
+ *     });
+ *
+ * @public
+ */
+
+res.sendfile = function (path, options, callback) {
+  var done = callback;
+  var req = this.req;
+  var res = this;
+  var next = req.next;
+  var opts = options || {};
+
+  // support function as second arg
+  if (typeof options === 'function') {
+    done = options;
+    opts = {};
+  }
+
+  // create file stream
+  var file = send(req, path, opts);
+
+  // transfer
+  sendfile(res, file, opts, function (err) {
+    if (done) return done(err);
+    if (err && err.code === 'EISDIR') return next();
+
+    // next() all but write errors
+    if (err && err.code !== 'ECONNABORTED' && err.syscall !== 'write') {
+      next(err);
+    }
+  });
+};
+
+res.sendfile = deprecate.function(res.sendfile,
+  'res.sendfile: Use res.sendFile instead');
+
+/**
+ * Transfer the file at the given `path` as an attachment.
+ *
+ * Optionally providing an alternate attachment `filename`,
+ * and optional callback `callback(err)`. The callback is invoked
+ * when the data transfer is complete, or when an error has
+ * occurred. Be sure to check `res.headersSent` if you plan to respond.
+ *
+ * Optionally providing an `options` object to use with `res.sendFile()`.
+ * This function will set the `Content-Disposition` header, overriding
+ * any `Content-Disposition` header passed as header options in order
+ * to set the attachment and filename.
+ *
+ * This method uses `res.sendFile()`.
+ *
+ * @public
+ */
+
+res.download = function download (path, filename, options, callback) {
+  var done = callback;
+  var name = filename;
+  var opts = options || null
+
+  // support function as second or third arg
+  if (typeof filename === 'function') {
+    done = filename;
+    name = null;
+    opts = null
+  } else if (typeof options === 'function') {
+    done = options
+    opts = null
+  }
+
+  // support optional filename, where options may be in it's place
+  if (typeof filename === 'object' &&
+    (typeof options === 'function' || options === undefined)) {
+    name = null
+    opts = filename
+  }
+
+  // set Content-Disposition when file is sent
+  var headers = {
+    'Content-Disposition': contentDisposition(name || path)
+  };
+
+  // merge user-provided headers
+  if (opts && opts.headers) {
+    var keys = Object.keys(opts.headers)
+    for (var i = 0; i < keys.length; i++) {
+      var key = keys[i]
+      if (key.toLowerCase() !== 'content-disposition') {
+        headers[key] = opts.headers[key]
+      }
+    }
+  }
+
+  // merge user-provided options
+  opts = Object.create(opts)
+  opts.headers = headers
+
+  // Resolve the full path for sendFile
+  var fullPath = !opts.root
+    ? resolve(path)
+    : path
+
+  // send file
+  return this.sendFile(fullPath, opts, done)
+};
+
+/**
+ * Set _Content-Type_ response header with `type` through `mime.lookup()`
+ * when it does not contain "/", or set the Content-Type to `type` otherwise.
+ *
+ * Examples:
+ *
+ *     res.type('.html');
+ *     res.type('html');
+ *     res.type('json');
+ *     res.type('application/json');
+ *     res.type('png');
+ *
+ * @param {String} type
+ * @return {ServerResponse} for chaining
+ * @public
+ */
+
+res.contentType =
+res.type = function contentType(type) {
+  var ct = type.indexOf('/') === -1
+    ? mime.lookup(type)
+    : type;
+
+  return this.set('Content-Type', ct);
+};
+
+/**
+ * Respond to the Acceptable formats using an `obj`
+ * of mime-type callbacks.
+ *
+ * This method uses `req.accepted`, an array of
+ * acceptable types ordered by their quality values.
+ * When "Accept" is not present the _first_ callback
+ * is invoked, otherwise the first match is used. When
+ * no match is performed the server responds with
+ * 406 "Not Acceptable".
+ *
+ * Content-Type is set for you, however if you choose
+ * you may alter this within the callback using `res.type()`
+ * or `res.set('Content-Type', ...)`.
+ *
+ *    res.format({
+ *      'text/plain': function(){
+ *        res.send('hey');
+ *      },
+ *
+ *      'text/html': function(){
+ *        res.send('<p>hey</p>');
+ *      },
+ *
+ *      'application/json': function () {
+ *        res.send({ message: 'hey' });
+ *      }
+ *    });
+ *
+ * In addition to canonicalized MIME types you may
+ * also use extnames mapped to these types:
+ *
+ *    res.format({
+ *      text: function(){
+ *        res.send('hey');
+ *      },
+ *
+ *      html: function(){
+ *        res.send('<p>hey</p>');
+ *      },
+ *
+ *      json: function(){
+ *        res.send({ message: 'hey' });
+ *      }
+ *    });
+ *
+ * By default Express passes an `Error`
+ * with a `.status` of 406 to `next(err)`
+ * if a match is not made. If you provide
+ * a `.default` callback it will be invoked
+ * instead.
+ *
+ * @param {Object} obj
+ * @return {ServerResponse} for chaining
+ * @public
+ */
+
+res.format = function(obj){
+  var req = this.req;
+  var next = req.next;
+
+  var keys = Object.keys(obj)
+    .filter(function (v) { return v !== 'default' })
+
+  var key = keys.length > 0
+    ? req.accepts(keys)
+    : false;
+
+  this.vary("Accept");
+
+  if (key) {
+    this.set('Content-Type', normalizeType(key).value);
+    obj[key](req, this, next);
+  } else if (obj.default) {
+    obj.default(req, this, next)
+  } else {
+    next(createError(406, {
+      types: normalizeTypes(keys).map(function (o) { return o.value })
+    }))
+  }
+
+  return this;
+};
+
+/**
+ * Set _Content-Disposition_ header to _attachment_ with optional `filename`.
+ *
+ * @param {String} filename
+ * @return {ServerResponse}
+ * @public
+ */
+
+res.attachment = function attachment(filename) {
+  if (filename) {
+    this.type(extname(filename));
+  }
+
+  this.set('Content-Disposition', contentDisposition(filename));
+
+  return this;
+};
+
+/**
+ * Append additional header `field` with value `val`.
+ *
+ * Example:
+ *
+ *    res.append('Link', ['<http://localhost/>', '<http://localhost:3000/>']);
+ *    res.append('Set-Cookie', 'foo=bar; Path=/; HttpOnly');
+ *    res.append('Warning', '199 Miscellaneous warning');
+ *
+ * @param {String} field
+ * @param {String|Array} val
+ * @return {ServerResponse} for chaining
+ * @public
+ */
+
+res.append = function append(field, val) {
+  var prev = this.get(field);
+  var value = val;
+
+  if (prev) {
+    // concat the new and prev vals
+    value = Array.isArray(prev) ? prev.concat(val)
+      : Array.isArray(val) ? [prev].concat(val)
+        : [prev, val]
+  }
+
+  return this.set(field, value);
+};
+
+/**
+ * Set header `field` to `val`, or pass
+ * an object of header fields.
+ *
+ * Examples:
+ *
+ *    res.set('Foo', ['bar', 'baz']);
+ *    res.set('Accept', 'application/json');
+ *    res.set({ Accept: 'text/plain', 'X-API-Key': 'tobi' });
+ *
+ * Aliased as `res.header()`.
+ *
+ * @param {String|Object} field
+ * @param {String|Array} val
+ * @return {ServerResponse} for chaining
+ * @public
+ */
+
+res.set =
+res.header = function header(field, val) {
+  if (arguments.length === 2) {
+    var value = Array.isArray(val)
+      ? val.map(String)
+      : String(val);
+
+    // add charset to content-type
+    if (field.toLowerCase() === 'content-type') {
+      if (Array.isArray(value)) {
+        throw new TypeError('Content-Type cannot be set to an Array');
+      }
+      if (!charsetRegExp.test(value)) {
+        var charset = mime.charsets.lookup(value.split(';')[0]);
+        if (charset) value += '; charset=' + charset.toLowerCase();
+      }
+    }
+
+    this.setHeader(field, value);
+  } else {
+    for (var key in field) {
+      this.set(key, field[key]);
+    }
+  }
+  return this;
+};
+
+/**
+ * Get value for header `field`.
+ *
+ * @param {String} field
+ * @return {String}
+ * @public
+ */
+
+res.get = function(field){
+  return this.getHeader(field);
+};
+
+/**
+ * Clear cookie `name`.
+ *
+ * @param {String} name
+ * @param {Object} [options]
+ * @return {ServerResponse} for chaining
+ * @public
+ */
+
+res.clearCookie = function clearCookie(name, options) {
+  if (options) {
+    if (options.maxAge) {
+      deprecate('res.clearCookie: Passing "options.maxAge" is deprecated. In v5.0.0 of Express, this option will be ignored, as res.clearCookie will automatically set cookies to expire immediately. Please update your code to omit this option.');
+    }
+    if (options.expires) {
+      deprecate('res.clearCookie: Passing "options.expires" is deprecated. In v5.0.0 of Express, this option will be ignored, as res.clearCookie will automatically set cookies to expire immediately. Please update your code to omit this option.');
+    }
+  }
+  var opts = merge({ expires: new Date(1), path: '/' }, options);
+
+  return this.cookie(name, '', opts);
+};
+
+/**
+ * Set cookie `name` to `value`, with the given `options`.
+ *
+ * Options:
+ *
+ *    - `maxAge`   max-age in milliseconds, converted to `expires`
+ *    - `signed`   sign the cookie
+ *    - `path`     defaults to "/"
+ *
+ * Examples:
+ *
+ *    // "Remember Me" for 15 minutes
+ *    res.cookie('rememberme', '1', { expires: new Date(Date.now() + 900000), httpOnly: true });
+ *
+ *    // same as above
+ *    res.cookie('rememberme', '1', { maxAge: 900000, httpOnly: true })
+ *
+ * @param {String} name
+ * @param {String|Object} value
+ * @param {Object} [options]
+ * @return {ServerResponse} for chaining
+ * @public
+ */
+
+res.cookie = function (name, value, options) {
+  var opts = merge({}, options);
+  var secret = this.req.secret;
+  var signed = opts.signed;
+
+  if (signed && !secret) {
+    throw new Error('cookieParser("secret") required for signed cookies');
+  }
+
+  var val = typeof value === 'object'
+    ? 'j:' + JSON.stringify(value)
+    : String(value);
+
+  if (signed) {
+    val = 's:' + sign(val, secret);
+  }
+
+  if (opts.maxAge != null) {
+    var maxAge = opts.maxAge - 0
+
+    if (!isNaN(maxAge)) {
+      opts.expires = new Date(Date.now() + maxAge)
+      opts.maxAge = Math.floor(maxAge / 1000)
+    }
+  }
+
+  if (opts.path == null) {
+    opts.path = '/';
+  }
+
+  this.append('Set-Cookie', cookie.serialize(name, String(val), opts));
+
+  return this;
+};
+
+/**
+ * Set the location header to `url`.
+ *
+ * The given `url` can also be "back", which redirects
+ * to the _Referrer_ or _Referer_ headers or "/".
+ *
+ * Examples:
+ *
+ *    res.location('/foo/bar').;
+ *    res.location('http://example.com');
+ *    res.location('../login');
+ *
+ * @param {String} url
+ * @return {ServerResponse} for chaining
+ * @public
+ */
+
+res.location = function location(url) {
+  var loc;
+
+  // "back" is an alias for the referrer
+  if (url === 'back') {
+    deprecate('res.location("back"): use res.location(req.get("Referrer") || "/") and refer to https://dub.sh/security-redirect for best practices');
+    loc = this.req.get('Referrer') || '/';
+  } else {
+    loc = String(url);
+  }
+
+  return this.set('Location', encodeUrl(loc));
+};
+
+/**
+ * Redirect to the given `url` with optional response `status`
+ * defaulting to 302.
+ *
+ * The resulting `url` is determined by `res.location()`, so
+ * it will play nicely with mounted apps, relative paths,
+ * `"back"` etc.
+ *
+ * Examples:
+ *
+ *    res.redirect('/foo/bar');
+ *    res.redirect('http://example.com');
+ *    res.redirect(301, 'http://example.com');
+ *    res.redirect('../login'); // /blog/post/1 -> /blog/login
+ *
+ * @public
+ */
+
+res.redirect = function redirect(url) {
+  var address = url;
+  var body;
+  var status = 302;
+
+  // allow status / url
+  if (arguments.length === 2) {
+    if (typeof arguments[0] === 'number') {
+      status = arguments[0];
+      address = arguments[1];
+    } else {
+      deprecate('res.redirect(url, status): Use res.redirect(status, url) instead');
+      status = arguments[1];
+    }
+  }
+
+  // Set location header
+  address = this.location(address).get('Location');
+
+  // Support text/{plain,html} by default
+  this.format({
+    text: function(){
+      body = statuses.message[status] + '. Redirecting to ' + address
+    },
+
+    html: function(){
+      var u = escapeHtml(address);
+      body = '<p>' + statuses.message[status] + '. Redirecting to ' + u + '</p>'
+    },
+
+    default: function(){
+      body = '';
+    }
+  });
+
+  // Respond
+  this.statusCode = status;
+  this.set('Content-Length', Buffer.byteLength(body));
+
+  if (this.req.method === 'HEAD') {
+    this.end();
+  } else {
+    this.end(body);
+  }
+};
+
+/**
+ * Add `field` to Vary. If already present in the Vary set, then
+ * this call is simply ignored.
+ *
+ * @param {Array|String} field
+ * @return {ServerResponse} for chaining
+ * @public
+ */
+
+res.vary = function(field){
+  // checks for back-compat
+  if (!field || (Array.isArray(field) && !field.length)) {
+    deprecate('res.vary(): Provide a field name');
+    return this;
+  }
+
+  vary(this, field);
+
+  return this;
+};
+
+/**
+ * Render `view` with the given `options` and optional callback `fn`.
+ * When a callback function is given a response will _not_ be made
+ * automatically, otherwise a response of _200_ and _text/html_ is given.
+ *
+ * Options:
+ *
+ *  - `cache`     boolean hinting to the engine it should cache
+ *  - `filename`  filename of the view being rendered
+ *
+ * @public
+ */
+
+res.render = function render(view, options, callback) {
+  var app = this.req.app;
+  var done = callback;
+  var opts = options || {};
+  var req = this.req;
+  var self = this;
+
+  // support callback function as second arg
+  if (typeof options === 'function') {
+    done = options;
+    opts = {};
+  }
+
+  // merge res.locals
+  opts._locals = self.locals;
+
+  // default callback to respond
+  done = done || function (err, str) {
+    if (err) return req.next(err);
+    self.send(str);
+  };
+
+  // render
+  app.render(view, opts, done);
+};
+
+// pipe the send file stream
+function sendfile(res, file, options, callback) {
+  var done = false;
+  var streaming;
+
+  // request aborted
+  function onaborted() {
+    if (done) return;
+    done = true;
+
+    var err = new Error('Request aborted');
+    err.code = 'ECONNABORTED';
+    callback(err);
+  }
+
+  // directory
+  function ondirectory() {
+    if (done) return;
+    done = true;
+
+    var err = new Error('EISDIR, read');
+    err.code = 'EISDIR';
+    callback(err);
+  }
+
+  // errors
+  function onerror(err) {
+    if (done) return;
+    done = true;
+    callback(err);
+  }
+
+  // ended
+  function onend() {
+    if (done) return;
+    done = true;
+    callback();
+  }
+
+  // file
+  function onfile() {
+    streaming = false;
+  }
+
+  // finished
+  function onfinish(err) {
+    if (err && err.code === 'ECONNRESET') return onaborted();
+    if (err) return onerror(err);
+    if (done) return;
+
+    setImmediate(function () {
+      if (streaming !== false && !done) {
+        onaborted();
+        return;
+      }
+
+      if (done) return;
+      done = true;
+      callback();
+    });
+  }
+
+  // streaming
+  function onstream() {
+    streaming = true;
+  }
+
+  file.on('directory', ondirectory);
+  file.on('end', onend);
+  file.on('error', onerror);
+  file.on('file', onfile);
+  file.on('stream', onstream);
+  onFinished(res, onfinish);
+
+  if (options.headers) {
+    // set headers on successful transfer
+    file.on('headers', function headers(res) {
+      var obj = options.headers;
+      var keys = Object.keys(obj);
+
+      for (var i = 0; i < keys.length; i++) {
+        var k = keys[i];
+        res.setHeader(k, obj[k]);
+      }
+    });
+  }
+
+  // pipe
+  file.pipe(res);
+}
+
+/**
+ * Stringify JSON, like JSON.stringify, but v8 optimized, with the
+ * ability to escape characters that can trigger HTML sniffing.
+ *
+ * @param {*} value
+ * @param {function} replacer
+ * @param {number} spaces
+ * @param {boolean} escape
+ * @returns {string}
+ * @private
+ */
+
+function stringify (value, replacer, spaces, escape) {
+  // v8 checks arguments.length for optimizing simple call
+  // https://bugs.chromium.org/p/v8/issues/detail?id=4730
+  var json = replacer || spaces
+    ? JSON.stringify(value, replacer, spaces)
+    : JSON.stringify(value);
+
+  if (escape && typeof json === 'string') {
+    json = json.replace(/[<>&]/g, function (c) {
+      switch (c.charCodeAt(0)) {
+        case 0x3c:
+          return '\\u003c'
+        case 0x3e:
+          return '\\u003e'
+        case 0x26:
+          return '\\u0026'
+        /* istanbul ignore next: unreachable default */
+        default:
+          return c
+      }
+    })
+  }
+
+  return json
+}
diff --git a/server/node_modules/express/lib/router/index.js b/server/node_modules/express/lib/router/index.js
new file mode 100644
index 0000000..abb3a6f
--- /dev/null
+++ b/server/node_modules/express/lib/router/index.js
@@ -0,0 +1,673 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var Route = require('./route');
+var Layer = require('./layer');
+var methods = require('methods');
+var mixin = require('utils-merge');
+var debug = require('debug')('express:router');
+var deprecate = require('depd')('express');
+var flatten = require('array-flatten');
+var parseUrl = require('parseurl');
+var setPrototypeOf = require('setprototypeof')
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var objectRegExp = /^\[object (\S+)\]$/;
+var slice = Array.prototype.slice;
+var toString = Object.prototype.toString;
+
+/**
+ * Initialize a new `Router` with the given `options`.
+ *
+ * @param {Object} [options]
+ * @return {Router} which is a callable function
+ * @public
+ */
+
+var proto = module.exports = function(options) {
+  var opts = options || {};
+
+  function router(req, res, next) {
+    router.handle(req, res, next);
+  }
+
+  // mixin Router class functions
+  setPrototypeOf(router, proto)
+
+  router.params = {};
+  router._params = [];
+  router.caseSensitive = opts.caseSensitive;
+  router.mergeParams = opts.mergeParams;
+  router.strict = opts.strict;
+  router.stack = [];
+
+  return router;
+};
+
+/**
+ * Map the given param placeholder `name`(s) to the given callback.
+ *
+ * Parameter mapping is used to provide pre-conditions to routes
+ * which use normalized placeholders. For example a _:user_id_ parameter
+ * could automatically load a user's information from the database without
+ * any additional code,
+ *
+ * The callback uses the same signature as middleware, the only difference
+ * being that the value of the placeholder is passed, in this case the _id_
+ * of the user. Once the `next()` function is invoked, just like middleware
+ * it will continue on to execute the route, or subsequent parameter functions.
+ *
+ * Just like in middleware, you must either respond to the request or call next
+ * to avoid stalling the request.
+ *
+ *  app.param('user_id', function(req, res, next, id){
+ *    User.find(id, function(err, user){
+ *      if (err) {
+ *        return next(err);
+ *      } else if (!user) {
+ *        return next(new Error('failed to load user'));
+ *      }
+ *      req.user = user;
+ *      next();
+ *    });
+ *  });
+ *
+ * @param {String} name
+ * @param {Function} fn
+ * @return {app} for chaining
+ * @public
+ */
+
+proto.param = function param(name, fn) {
+  // param logic
+  if (typeof name === 'function') {
+    deprecate('router.param(fn): Refactor to use path params');
+    this._params.push(name);
+    return;
+  }
+
+  // apply param functions
+  var params = this._params;
+  var len = params.length;
+  var ret;
+
+  if (name[0] === ':') {
+    deprecate('router.param(' + JSON.stringify(name) + ', fn): Use router.param(' + JSON.stringify(name.slice(1)) + ', fn) instead')
+    name = name.slice(1)
+  }
+
+  for (var i = 0; i < len; ++i) {
+    if (ret = params[i](name, fn)) {
+      fn = ret;
+    }
+  }
+
+  // ensure we end up with a
+  // middleware function
+  if ('function' !== typeof fn) {
+    throw new Error('invalid param() call for ' + name + ', got ' + fn);
+  }
+
+  (this.params[name] = this.params[name] || []).push(fn);
+  return this;
+};
+
+/**
+ * Dispatch a req, res into the router.
+ * @private
+ */
+
+proto.handle = function handle(req, res, out) {
+  var self = this;
+
+  debug('dispatching %s %s', req.method, req.url);
+
+  var idx = 0;
+  var protohost = getProtohost(req.url) || ''
+  var removed = '';
+  var slashAdded = false;
+  var sync = 0
+  var paramcalled = {};
+
+  // store options for OPTIONS request
+  // only used if OPTIONS request
+  var options = [];
+
+  // middleware and routes
+  var stack = self.stack;
+
+  // manage inter-router variables
+  var parentParams = req.params;
+  var parentUrl = req.baseUrl || '';
+  var done = restore(out, req, 'baseUrl', 'next', 'params');
+
+  // setup next layer
+  req.next = next;
+
+  // for options requests, respond with a default if nothing else responds
+  if (req.method === 'OPTIONS') {
+    done = wrap(done, function(old, err) {
+      if (err || options.length === 0) return old(err);
+      sendOptionsResponse(res, options, old);
+    });
+  }
+
+  // setup basic req values
+  req.baseUrl = parentUrl;
+  req.originalUrl = req.originalUrl || req.url;
+
+  next();
+
+  function next(err) {
+    var layerError = err === 'route'
+      ? null
+      : err;
+
+    // remove added slash
+    if (slashAdded) {
+      req.url = req.url.slice(1)
+      slashAdded = false;
+    }
+
+    // restore altered req.url
+    if (removed.length !== 0) {
+      req.baseUrl = parentUrl;
+      req.url = protohost + removed + req.url.slice(protohost.length)
+      removed = '';
+    }
+
+    // signal to exit router
+    if (layerError === 'router') {
+      setImmediate(done, null)
+      return
+    }
+
+    // no more matching layers
+    if (idx >= stack.length) {
+      setImmediate(done, layerError);
+      return;
+    }
+
+    // max sync stack
+    if (++sync > 100) {
+      return setImmediate(next, err)
+    }
+
+    // get pathname of request
+    var path = getPathname(req);
+
+    if (path == null) {
+      return done(layerError);
+    }
+
+    // find next matching layer
+    var layer;
+    var match;
+    var route;
+
+    while (match !== true && idx < stack.length) {
+      layer = stack[idx++];
+      match = matchLayer(layer, path);
+      route = layer.route;
+
+      if (typeof match !== 'boolean') {
+        // hold on to layerError
+        layerError = layerError || match;
+      }
+
+      if (match !== true) {
+        continue;
+      }
+
+      if (!route) {
+        // process non-route handlers normally
+        continue;
+      }
+
+      if (layerError) {
+        // routes do not match with a pending error
+        match = false;
+        continue;
+      }
+
+      var method = req.method;
+      var has_method = route._handles_method(method);
+
+      // build up automatic options response
+      if (!has_method && method === 'OPTIONS') {
+        appendMethods(options, route._options());
+      }
+
+      // don't even bother matching route
+      if (!has_method && method !== 'HEAD') {
+        match = false;
+      }
+    }
+
+    // no match
+    if (match !== true) {
+      return done(layerError);
+    }
+
+    // store route for dispatch on change
+    if (route) {
+      req.route = route;
+    }
+
+    // Capture one-time layer values
+    req.params = self.mergeParams
+      ? mergeParams(layer.params, parentParams)
+      : layer.params;
+    var layerPath = layer.path;
+
+    // this should be done for the layer
+    self.process_params(layer, paramcalled, req, res, function (err) {
+      if (err) {
+        next(layerError || err)
+      } else if (route) {
+        layer.handle_request(req, res, next)
+      } else {
+        trim_prefix(layer, layerError, layerPath, path)
+      }
+
+      sync = 0
+    });
+  }
+
+  function trim_prefix(layer, layerError, layerPath, path) {
+    if (layerPath.length !== 0) {
+      // Validate path is a prefix match
+      if (layerPath !== path.slice(0, layerPath.length)) {
+        next(layerError)
+        return
+      }
+
+      // Validate path breaks on a path separator
+      var c = path[layerPath.length]
+      if (c && c !== '/' && c !== '.') return next(layerError)
+
+      // Trim off the part of the url that matches the route
+      // middleware (.use stuff) needs to have the path stripped
+      debug('trim prefix (%s) from url %s', layerPath, req.url);
+      removed = layerPath;
+      req.url = protohost + req.url.slice(protohost.length + removed.length)
+
+      // Ensure leading slash
+      if (!protohost && req.url[0] !== '/') {
+        req.url = '/' + req.url;
+        slashAdded = true;
+      }
+
+      // Setup base URL (no trailing slash)
+      req.baseUrl = parentUrl + (removed[removed.length - 1] === '/'
+        ? removed.substring(0, removed.length - 1)
+        : removed);
+    }
+
+    debug('%s %s : %s', layer.name, layerPath, req.originalUrl);
+
+    if (layerError) {
+      layer.handle_error(layerError, req, res, next);
+    } else {
+      layer.handle_request(req, res, next);
+    }
+  }
+};
+
+/**
+ * Process any parameters for the layer.
+ * @private
+ */
+
+proto.process_params = function process_params(layer, called, req, res, done) {
+  var params = this.params;
+
+  // captured parameters from the layer, keys and values
+  var keys = layer.keys;
+
+  // fast track
+  if (!keys || keys.length === 0) {
+    return done();
+  }
+
+  var i = 0;
+  var name;
+  var paramIndex = 0;
+  var key;
+  var paramVal;
+  var paramCallbacks;
+  var paramCalled;
+
+  // process params in order
+  // param callbacks can be async
+  function param(err) {
+    if (err) {
+      return done(err);
+    }
+
+    if (i >= keys.length ) {
+      return done();
+    }
+
+    paramIndex = 0;
+    key = keys[i++];
+    name = key.name;
+    paramVal = req.params[name];
+    paramCallbacks = params[name];
+    paramCalled = called[name];
+
+    if (paramVal === undefined || !paramCallbacks) {
+      return param();
+    }
+
+    // param previously called with same value or error occurred
+    if (paramCalled && (paramCalled.match === paramVal
+      || (paramCalled.error && paramCalled.error !== 'route'))) {
+      // restore value
+      req.params[name] = paramCalled.value;
+
+      // next param
+      return param(paramCalled.error);
+    }
+
+    called[name] = paramCalled = {
+      error: null,
+      match: paramVal,
+      value: paramVal
+    };
+
+    paramCallback();
+  }
+
+  // single param callbacks
+  function paramCallback(err) {
+    var fn = paramCallbacks[paramIndex++];
+
+    // store updated value
+    paramCalled.value = req.params[key.name];
+
+    if (err) {
+      // store error
+      paramCalled.error = err;
+      param(err);
+      return;
+    }
+
+    if (!fn) return param();
+
+    try {
+      fn(req, res, paramCallback, paramVal, key.name);
+    } catch (e) {
+      paramCallback(e);
+    }
+  }
+
+  param();
+};
+
+/**
+ * Use the given middleware function, with optional path, defaulting to "/".
+ *
+ * Use (like `.all`) will run for any http METHOD, but it will not add
+ * handlers for those methods so OPTIONS requests will not consider `.use`
+ * functions even if they could respond.
+ *
+ * The other difference is that _route_ path is stripped and not visible
+ * to the handler function. The main effect of this feature is that mounted
+ * handlers can operate without any code changes regardless of the "prefix"
+ * pathname.
+ *
+ * @public
+ */
+
+proto.use = function use(fn) {
+  var offset = 0;
+  var path = '/';
+
+  // default path to '/'
+  // disambiguate router.use([fn])
+  if (typeof fn !== 'function') {
+    var arg = fn;
+
+    while (Array.isArray(arg) && arg.length !== 0) {
+      arg = arg[0];
+    }
+
+    // first arg is the path
+    if (typeof arg !== 'function') {
+      offset = 1;
+      path = fn;
+    }
+  }
+
+  var callbacks = flatten(slice.call(arguments, offset));
+
+  if (callbacks.length === 0) {
+    throw new TypeError('Router.use() requires a middleware function')
+  }
+
+  for (var i = 0; i < callbacks.length; i++) {
+    var fn = callbacks[i];
+
+    if (typeof fn !== 'function') {
+      throw new TypeError('Router.use() requires a middleware function but got a ' + gettype(fn))
+    }
+
+    // add the middleware
+    debug('use %o %s', path, fn.name || '<anonymous>')
+
+    var layer = new Layer(path, {
+      sensitive: this.caseSensitive,
+      strict: false,
+      end: false
+    }, fn);
+
+    layer.route = undefined;
+
+    this.stack.push(layer);
+  }
+
+  return this;
+};
+
+/**
+ * Create a new Route for the given path.
+ *
+ * Each route contains a separate middleware stack and VERB handlers.
+ *
+ * See the Route api documentation for details on adding handlers
+ * and middleware to routes.
+ *
+ * @param {String} path
+ * @return {Route}
+ * @public
+ */
+
+proto.route = function route(path) {
+  var route = new Route(path);
+
+  var layer = new Layer(path, {
+    sensitive: this.caseSensitive,
+    strict: this.strict,
+    end: true
+  }, route.dispatch.bind(route));
+
+  layer.route = route;
+
+  this.stack.push(layer);
+  return route;
+};
+
+// create Router#VERB functions
+methods.concat('all').forEach(function(method){
+  proto[method] = function(path){
+    var route = this.route(path)
+    route[method].apply(route, slice.call(arguments, 1));
+    return this;
+  };
+});
+
+// append methods to a list of methods
+function appendMethods(list, addition) {
+  for (var i = 0; i < addition.length; i++) {
+    var method = addition[i];
+    if (list.indexOf(method) === -1) {
+      list.push(method);
+    }
+  }
+}
+
+// get pathname of request
+function getPathname(req) {
+  try {
+    return parseUrl(req).pathname;
+  } catch (err) {
+    return undefined;
+  }
+}
+
+// Get get protocol + host for a URL
+function getProtohost(url) {
+  if (typeof url !== 'string' || url.length === 0 || url[0] === '/') {
+    return undefined
+  }
+
+  var searchIndex = url.indexOf('?')
+  var pathLength = searchIndex !== -1
+    ? searchIndex
+    : url.length
+  var fqdnIndex = url.slice(0, pathLength).indexOf('://')
+
+  return fqdnIndex !== -1
+    ? url.substring(0, url.indexOf('/', 3 + fqdnIndex))
+    : undefined
+}
+
+// get type for error message
+function gettype(obj) {
+  var type = typeof obj;
+
+  if (type !== 'object') {
+    return type;
+  }
+
+  // inspect [[Class]] for objects
+  return toString.call(obj)
+    .replace(objectRegExp, '$1');
+}
+
+/**
+ * Match path to a layer.
+ *
+ * @param {Layer} layer
+ * @param {string} path
+ * @private
+ */
+
+function matchLayer(layer, path) {
+  try {
+    return layer.match(path);
+  } catch (err) {
+    return err;
+  }
+}
+
+// merge params with parent params
+function mergeParams(params, parent) {
+  if (typeof parent !== 'object' || !parent) {
+    return params;
+  }
+
+  // make copy of parent for base
+  var obj = mixin({}, parent);
+
+  // simple non-numeric merging
+  if (!(0 in params) || !(0 in parent)) {
+    return mixin(obj, params);
+  }
+
+  var i = 0;
+  var o = 0;
+
+  // determine numeric gaps
+  while (i in params) {
+    i++;
+  }
+
+  while (o in parent) {
+    o++;
+  }
+
+  // offset numeric indices in params before merge
+  for (i--; i >= 0; i--) {
+    params[i + o] = params[i];
+
+    // create holes for the merge when necessary
+    if (i < o) {
+      delete params[i];
+    }
+  }
+
+  return mixin(obj, params);
+}
+
+// restore obj props after function
+function restore(fn, obj) {
+  var props = new Array(arguments.length - 2);
+  var vals = new Array(arguments.length - 2);
+
+  for (var i = 0; i < props.length; i++) {
+    props[i] = arguments[i + 2];
+    vals[i] = obj[props[i]];
+  }
+
+  return function () {
+    // restore vals
+    for (var i = 0; i < props.length; i++) {
+      obj[props[i]] = vals[i];
+    }
+
+    return fn.apply(this, arguments);
+  };
+}
+
+// send an OPTIONS response
+function sendOptionsResponse(res, options, next) {
+  try {
+    var body = options.join(',');
+    res.set('Allow', body);
+    res.send(body);
+  } catch (err) {
+    next(err);
+  }
+}
+
+// wrap a function
+function wrap(old, fn) {
+  return function proxy() {
+    var args = new Array(arguments.length + 1);
+
+    args[0] = old;
+    for (var i = 0, len = arguments.length; i < len; i++) {
+      args[i + 1] = arguments[i];
+    }
+
+    fn.apply(this, args);
+  };
+}
diff --git a/server/node_modules/express/lib/router/layer.js b/server/node_modules/express/lib/router/layer.js
new file mode 100644
index 0000000..4dc8e86
--- /dev/null
+++ b/server/node_modules/express/lib/router/layer.js
@@ -0,0 +1,181 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var pathRegexp = require('path-to-regexp');
+var debug = require('debug')('express:router:layer');
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var hasOwnProperty = Object.prototype.hasOwnProperty;
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = Layer;
+
+function Layer(path, options, fn) {
+  if (!(this instanceof Layer)) {
+    return new Layer(path, options, fn);
+  }
+
+  debug('new %o', path)
+  var opts = options || {};
+
+  this.handle = fn;
+  this.name = fn.name || '<anonymous>';
+  this.params = undefined;
+  this.path = undefined;
+  this.regexp = pathRegexp(path, this.keys = [], opts);
+
+  // set fast path flags
+  this.regexp.fast_star = path === '*'
+  this.regexp.fast_slash = path === '/' && opts.end === false
+}
+
+/**
+ * Handle the error for the layer.
+ *
+ * @param {Error} error
+ * @param {Request} req
+ * @param {Response} res
+ * @param {function} next
+ * @api private
+ */
+
+Layer.prototype.handle_error = function handle_error(error, req, res, next) {
+  var fn = this.handle;
+
+  if (fn.length !== 4) {
+    // not a standard error handler
+    return next(error);
+  }
+
+  try {
+    fn(error, req, res, next);
+  } catch (err) {
+    next(err);
+  }
+};
+
+/**
+ * Handle the request for the layer.
+ *
+ * @param {Request} req
+ * @param {Response} res
+ * @param {function} next
+ * @api private
+ */
+
+Layer.prototype.handle_request = function handle(req, res, next) {
+  var fn = this.handle;
+
+  if (fn.length > 3) {
+    // not a standard request handler
+    return next();
+  }
+
+  try {
+    fn(req, res, next);
+  } catch (err) {
+    next(err);
+  }
+};
+
+/**
+ * Check if this route matches `path`, if so
+ * populate `.params`.
+ *
+ * @param {String} path
+ * @return {Boolean}
+ * @api private
+ */
+
+Layer.prototype.match = function match(path) {
+  var match
+
+  if (path != null) {
+    // fast path non-ending match for / (any path matches)
+    if (this.regexp.fast_slash) {
+      this.params = {}
+      this.path = ''
+      return true
+    }
+
+    // fast path for * (everything matched in a param)
+    if (this.regexp.fast_star) {
+      this.params = {'0': decode_param(path)}
+      this.path = path
+      return true
+    }
+
+    // match the path
+    match = this.regexp.exec(path)
+  }
+
+  if (!match) {
+    this.params = undefined;
+    this.path = undefined;
+    return false;
+  }
+
+  // store values
+  this.params = {};
+  this.path = match[0]
+
+  var keys = this.keys;
+  var params = this.params;
+
+  for (var i = 1; i < match.length; i++) {
+    var key = keys[i - 1];
+    var prop = key.name;
+    var val = decode_param(match[i])
+
+    if (val !== undefined || !(hasOwnProperty.call(params, prop))) {
+      params[prop] = val;
+    }
+  }
+
+  return true;
+};
+
+/**
+ * Decode param value.
+ *
+ * @param {string} val
+ * @return {string}
+ * @private
+ */
+
+function decode_param(val) {
+  if (typeof val !== 'string' || val.length === 0) {
+    return val;
+  }
+
+  try {
+    return decodeURIComponent(val);
+  } catch (err) {
+    if (err instanceof URIError) {
+      err.message = 'Failed to decode param \'' + val + '\'';
+      err.status = err.statusCode = 400;
+    }
+
+    throw err;
+  }
+}
diff --git a/server/node_modules/express/lib/router/route.js b/server/node_modules/express/lib/router/route.js
new file mode 100644
index 0000000..a65756d
--- /dev/null
+++ b/server/node_modules/express/lib/router/route.js
@@ -0,0 +1,230 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var debug = require('debug')('express:router:route');
+var flatten = require('array-flatten');
+var Layer = require('./layer');
+var methods = require('methods');
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var slice = Array.prototype.slice;
+var toString = Object.prototype.toString;
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = Route;
+
+/**
+ * Initialize `Route` with the given `path`,
+ *
+ * @param {String} path
+ * @public
+ */
+
+function Route(path) {
+  this.path = path;
+  this.stack = [];
+
+  debug('new %o', path)
+
+  // route handlers for various http methods
+  this.methods = {};
+}
+
+/**
+ * Determine if the route handles a given method.
+ * @private
+ */
+
+Route.prototype._handles_method = function _handles_method(method) {
+  if (this.methods._all) {
+    return true;
+  }
+
+  // normalize name
+  var name = typeof method === 'string'
+    ? method.toLowerCase()
+    : method
+
+  if (name === 'head' && !this.methods['head']) {
+    name = 'get';
+  }
+
+  return Boolean(this.methods[name]);
+};
+
+/**
+ * @return {Array} supported HTTP methods
+ * @private
+ */
+
+Route.prototype._options = function _options() {
+  var methods = Object.keys(this.methods);
+
+  // append automatic head
+  if (this.methods.get && !this.methods.head) {
+    methods.push('head');
+  }
+
+  for (var i = 0; i < methods.length; i++) {
+    // make upper case
+    methods[i] = methods[i].toUpperCase();
+  }
+
+  return methods;
+};
+
+/**
+ * dispatch req, res into this route
+ * @private
+ */
+
+Route.prototype.dispatch = function dispatch(req, res, done) {
+  var idx = 0;
+  var stack = this.stack;
+  var sync = 0
+
+  if (stack.length === 0) {
+    return done();
+  }
+  var method = typeof req.method === 'string'
+    ? req.method.toLowerCase()
+    : req.method
+
+  if (method === 'head' && !this.methods['head']) {
+    method = 'get';
+  }
+
+  req.route = this;
+
+  next();
+
+  function next(err) {
+    // signal to exit route
+    if (err && err === 'route') {
+      return done();
+    }
+
+    // signal to exit router
+    if (err && err === 'router') {
+      return done(err)
+    }
+
+    // max sync stack
+    if (++sync > 100) {
+      return setImmediate(next, err)
+    }
+
+    var layer = stack[idx++]
+
+    // end of layers
+    if (!layer) {
+      return done(err)
+    }
+
+    if (layer.method && layer.method !== method) {
+      next(err)
+    } else if (err) {
+      layer.handle_error(err, req, res, next);
+    } else {
+      layer.handle_request(req, res, next);
+    }
+
+    sync = 0
+  }
+};
+
+/**
+ * Add a handler for all HTTP verbs to this route.
+ *
+ * Behaves just like middleware and can respond or call `next`
+ * to continue processing.
+ *
+ * You can use multiple `.all` call to add multiple handlers.
+ *
+ *   function check_something(req, res, next){
+ *     next();
+ *   };
+ *
+ *   function validate_user(req, res, next){
+ *     next();
+ *   };
+ *
+ *   route
+ *   .all(validate_user)
+ *   .all(check_something)
+ *   .get(function(req, res, next){
+ *     res.send('hello world');
+ *   });
+ *
+ * @param {function} handler
+ * @return {Route} for chaining
+ * @api public
+ */
+
+Route.prototype.all = function all() {
+  var handles = flatten(slice.call(arguments));
+
+  for (var i = 0; i < handles.length; i++) {
+    var handle = handles[i];
+
+    if (typeof handle !== 'function') {
+      var type = toString.call(handle);
+      var msg = 'Route.all() requires a callback function but got a ' + type
+      throw new TypeError(msg);
+    }
+
+    var layer = Layer('/', {}, handle);
+    layer.method = undefined;
+
+    this.methods._all = true;
+    this.stack.push(layer);
+  }
+
+  return this;
+};
+
+methods.forEach(function(method){
+  Route.prototype[method] = function(){
+    var handles = flatten(slice.call(arguments));
+
+    for (var i = 0; i < handles.length; i++) {
+      var handle = handles[i];
+
+      if (typeof handle !== 'function') {
+        var type = toString.call(handle);
+        var msg = 'Route.' + method + '() requires a callback function but got a ' + type
+        throw new Error(msg);
+      }
+
+      debug('%s %o', method, this.path)
+
+      var layer = Layer('/', {}, handle);
+      layer.method = method;
+
+      this.methods[method] = true;
+      this.stack.push(layer);
+    }
+
+    return this;
+  };
+});
diff --git a/server/node_modules/express/lib/utils.js b/server/node_modules/express/lib/utils.js
new file mode 100644
index 0000000..56e12b9
--- /dev/null
+++ b/server/node_modules/express/lib/utils.js
@@ -0,0 +1,303 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @api private
+ */
+
+var Buffer = require('safe-buffer').Buffer
+var contentDisposition = require('content-disposition');
+var contentType = require('content-type');
+var deprecate = require('depd')('express');
+var flatten = require('array-flatten');
+var mime = require('send').mime;
+var etag = require('etag');
+var proxyaddr = require('proxy-addr');
+var qs = require('qs');
+var querystring = require('querystring');
+
+/**
+ * Return strong ETag for `body`.
+ *
+ * @param {String|Buffer} body
+ * @param {String} [encoding]
+ * @return {String}
+ * @api private
+ */
+
+exports.etag = createETagGenerator({ weak: false })
+
+/**
+ * Return weak ETag for `body`.
+ *
+ * @param {String|Buffer} body
+ * @param {String} [encoding]
+ * @return {String}
+ * @api private
+ */
+
+exports.wetag = createETagGenerator({ weak: true })
+
+/**
+ * Check if `path` looks absolute.
+ *
+ * @param {String} path
+ * @return {Boolean}
+ * @api private
+ */
+
+exports.isAbsolute = function(path){
+  if ('/' === path[0]) return true;
+  if (':' === path[1] && ('\\' === path[2] || '/' === path[2])) return true; // Windows device path
+  if ('\\\\' === path.substring(0, 2)) return true; // Microsoft Azure absolute path
+};
+
+/**
+ * Flatten the given `arr`.
+ *
+ * @param {Array} arr
+ * @return {Array}
+ * @api private
+ */
+
+exports.flatten = deprecate.function(flatten,
+  'utils.flatten: use array-flatten npm module instead');
+
+/**
+ * Normalize the given `type`, for example "html" becomes "text/html".
+ *
+ * @param {String} type
+ * @return {Object}
+ * @api private
+ */
+
+exports.normalizeType = function(type){
+  return ~type.indexOf('/')
+    ? acceptParams(type)
+    : { value: mime.lookup(type), params: {} };
+};
+
+/**
+ * Normalize `types`, for example "html" becomes "text/html".
+ *
+ * @param {Array} types
+ * @return {Array}
+ * @api private
+ */
+
+exports.normalizeTypes = function(types){
+  var ret = [];
+
+  for (var i = 0; i < types.length; ++i) {
+    ret.push(exports.normalizeType(types[i]));
+  }
+
+  return ret;
+};
+
+/**
+ * Generate Content-Disposition header appropriate for the filename.
+ * non-ascii filenames are urlencoded and a filename* parameter is added
+ *
+ * @param {String} filename
+ * @return {String}
+ * @api private
+ */
+
+exports.contentDisposition = deprecate.function(contentDisposition,
+  'utils.contentDisposition: use content-disposition npm module instead');
+
+/**
+ * Parse accept params `str` returning an
+ * object with `.value`, `.quality` and `.params`.
+ *
+ * @param {String} str
+ * @return {Object}
+ * @api private
+ */
+
+function acceptParams (str) {
+  var parts = str.split(/ *; */);
+  var ret = { value: parts[0], quality: 1, params: {} }
+
+  for (var i = 1; i < parts.length; ++i) {
+    var pms = parts[i].split(/ *= */);
+    if ('q' === pms[0]) {
+      ret.quality = parseFloat(pms[1]);
+    } else {
+      ret.params[pms[0]] = pms[1];
+    }
+  }
+
+  return ret;
+}
+
+/**
+ * Compile "etag" value to function.
+ *
+ * @param  {Boolean|String|Function} val
+ * @return {Function}
+ * @api private
+ */
+
+exports.compileETag = function(val) {
+  var fn;
+
+  if (typeof val === 'function') {
+    return val;
+  }
+
+  switch (val) {
+    case true:
+    case 'weak':
+      fn = exports.wetag;
+      break;
+    case false:
+      break;
+    case 'strong':
+      fn = exports.etag;
+      break;
+    default:
+      throw new TypeError('unknown value for etag function: ' + val);
+  }
+
+  return fn;
+}
+
+/**
+ * Compile "query parser" value to function.
+ *
+ * @param  {String|Function} val
+ * @return {Function}
+ * @api private
+ */
+
+exports.compileQueryParser = function compileQueryParser(val) {
+  var fn;
+
+  if (typeof val === 'function') {
+    return val;
+  }
+
+  switch (val) {
+    case true:
+    case 'simple':
+      fn = querystring.parse;
+      break;
+    case false:
+      fn = newObject;
+      break;
+    case 'extended':
+      fn = parseExtendedQueryString;
+      break;
+    default:
+      throw new TypeError('unknown value for query parser function: ' + val);
+  }
+
+  return fn;
+}
+
+/**
+ * Compile "proxy trust" value to function.
+ *
+ * @param  {Boolean|String|Number|Array|Function} val
+ * @return {Function}
+ * @api private
+ */
+
+exports.compileTrust = function(val) {
+  if (typeof val === 'function') return val;
+
+  if (val === true) {
+    // Support plain true/false
+    return function(){ return true };
+  }
+
+  if (typeof val === 'number') {
+    // Support trusting hop count
+    return function(a, i){ return i < val };
+  }
+
+  if (typeof val === 'string') {
+    // Support comma-separated values
+    val = val.split(',')
+      .map(function (v) { return v.trim() })
+  }
+
+  return proxyaddr.compile(val || []);
+}
+
+/**
+ * Set the charset in a given Content-Type string.
+ *
+ * @param {String} type
+ * @param {String} charset
+ * @return {String}
+ * @api private
+ */
+
+exports.setCharset = function setCharset(type, charset) {
+  if (!type || !charset) {
+    return type;
+  }
+
+  // parse type
+  var parsed = contentType.parse(type);
+
+  // set charset
+  parsed.parameters.charset = charset;
+
+  // format type
+  return contentType.format(parsed);
+};
+
+/**
+ * Create an ETag generator function, generating ETags with
+ * the given options.
+ *
+ * @param {object} options
+ * @return {function}
+ * @private
+ */
+
+function createETagGenerator (options) {
+  return function generateETag (body, encoding) {
+    var buf = !Buffer.isBuffer(body)
+      ? Buffer.from(body, encoding)
+      : body
+
+    return etag(buf, options)
+  }
+}
+
+/**
+ * Parse an extended query string with qs.
+ *
+ * @param {String} str
+ * @return {Object}
+ * @private
+ */
+
+function parseExtendedQueryString(str) {
+  return qs.parse(str, {
+    allowPrototypes: true
+  });
+}
+
+/**
+ * Return new empty object.
+ *
+ * @return {Object}
+ * @api private
+ */
+
+function newObject() {
+  return {};
+}
diff --git a/server/node_modules/express/lib/view.js b/server/node_modules/express/lib/view.js
new file mode 100644
index 0000000..c08ab4d
--- /dev/null
+++ b/server/node_modules/express/lib/view.js
@@ -0,0 +1,182 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2013 Roman Shtylman
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var debug = require('debug')('express:view');
+var path = require('path');
+var fs = require('fs');
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var dirname = path.dirname;
+var basename = path.basename;
+var extname = path.extname;
+var join = path.join;
+var resolve = path.resolve;
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = View;
+
+/**
+ * Initialize a new `View` with the given `name`.
+ *
+ * Options:
+ *
+ *   - `defaultEngine` the default template engine name
+ *   - `engines` template engine require() cache
+ *   - `root` root path for view lookup
+ *
+ * @param {string} name
+ * @param {object} options
+ * @public
+ */
+
+function View(name, options) {
+  var opts = options || {};
+
+  this.defaultEngine = opts.defaultEngine;
+  this.ext = extname(name);
+  this.name = name;
+  this.root = opts.root;
+
+  if (!this.ext && !this.defaultEngine) {
+    throw new Error('No default engine was specified and no extension was provided.');
+  }
+
+  var fileName = name;
+
+  if (!this.ext) {
+    // get extension from default engine name
+    this.ext = this.defaultEngine[0] !== '.'
+      ? '.' + this.defaultEngine
+      : this.defaultEngine;
+
+    fileName += this.ext;
+  }
+
+  if (!opts.engines[this.ext]) {
+    // load engine
+    var mod = this.ext.slice(1)
+    debug('require "%s"', mod)
+
+    // default engine export
+    var fn = require(mod).__express
+
+    if (typeof fn !== 'function') {
+      throw new Error('Module "' + mod + '" does not provide a view engine.')
+    }
+
+    opts.engines[this.ext] = fn
+  }
+
+  // store loaded engine
+  this.engine = opts.engines[this.ext];
+
+  // lookup path
+  this.path = this.lookup(fileName);
+}
+
+/**
+ * Lookup view by the given `name`
+ *
+ * @param {string} name
+ * @private
+ */
+
+View.prototype.lookup = function lookup(name) {
+  var path;
+  var roots = [].concat(this.root);
+
+  debug('lookup "%s"', name);
+
+  for (var i = 0; i < roots.length && !path; i++) {
+    var root = roots[i];
+
+    // resolve the path
+    var loc = resolve(root, name);
+    var dir = dirname(loc);
+    var file = basename(loc);
+
+    // resolve the file
+    path = this.resolve(dir, file);
+  }
+
+  return path;
+};
+
+/**
+ * Render with the given options.
+ *
+ * @param {object} options
+ * @param {function} callback
+ * @private
+ */
+
+View.prototype.render = function render(options, callback) {
+  debug('render "%s"', this.path);
+  this.engine(this.path, options, callback);
+};
+
+/**
+ * Resolve the file within the given directory.
+ *
+ * @param {string} dir
+ * @param {string} file
+ * @private
+ */
+
+View.prototype.resolve = function resolve(dir, file) {
+  var ext = this.ext;
+
+  // <path>.<ext>
+  var path = join(dir, file);
+  var stat = tryStat(path);
+
+  if (stat && stat.isFile()) {
+    return path;
+  }
+
+  // <path>/index.<ext>
+  path = join(dir, basename(file, ext), 'index' + ext);
+  stat = tryStat(path);
+
+  if (stat && stat.isFile()) {
+    return path;
+  }
+};
+
+/**
+ * Return a stat, maybe.
+ *
+ * @param {string} path
+ * @return {fs.Stats}
+ * @private
+ */
+
+function tryStat(path) {
+  debug('stat "%s"', path);
+
+  try {
+    return fs.statSync(path);
+  } catch (e) {
+    return undefined;
+  }
+}
diff --git a/server/node_modules/express/package.json b/server/node_modules/express/package.json
new file mode 100644
index 0000000..4322f1a
--- /dev/null
+++ b/server/node_modules/express/package.json
@@ -0,0 +1,102 @@
+{
+  "name": "express",
+  "description": "Fast, unopinionated, minimalist web framework",
+  "version": "4.22.1",
+  "author": "TJ Holowaychuk <tj@vision-media.ca>",
+  "contributors": [
+    "Aaron Heckmann <aaron.heckmann+github@gmail.com>",
+    "Ciaran Jessup <ciaranj@gmail.com>",
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Guillermo Rauch <rauchg@gmail.com>",
+    "Jonathan Ong <me@jongleberry.com>",
+    "Roman Shtylman <shtylman+expressjs@gmail.com>",
+    "Young Jae Sim <hanul@hanul.me>"
+  ],
+  "license": "MIT",
+  "repository": "expressjs/express",
+  "homepage": "http://expressjs.com/",
+  "funding": {
+    "type": "opencollective",
+    "url": "https://opencollective.com/express"
+  },
+  "keywords": [
+    "express",
+    "framework",
+    "sinatra",
+    "web",
+    "http",
+    "rest",
+    "restful",
+    "router",
+    "app",
+    "api"
+  ],
+  "dependencies": {
+    "accepts": "~1.3.8",
+    "array-flatten": "1.1.1",
+    "body-parser": "~1.20.3",
+    "content-disposition": "~0.5.4",
+    "content-type": "~1.0.4",
+    "cookie": "~0.7.1",
+    "cookie-signature": "~1.0.6",
+    "debug": "2.6.9",
+    "depd": "2.0.0",
+    "encodeurl": "~2.0.0",
+    "escape-html": "~1.0.3",
+    "etag": "~1.8.1",
+    "finalhandler": "~1.3.1",
+    "fresh": "~0.5.2",
+    "http-errors": "~2.0.0",
+    "merge-descriptors": "1.0.3",
+    "methods": "~1.1.2",
+    "on-finished": "~2.4.1",
+    "parseurl": "~1.3.3",
+    "path-to-regexp": "~0.1.12",
+    "proxy-addr": "~2.0.7",
+    "qs": "~6.14.0",
+    "range-parser": "~1.2.1",
+    "safe-buffer": "5.2.1",
+    "send": "~0.19.0",
+    "serve-static": "~1.16.2",
+    "setprototypeof": "1.2.0",
+    "statuses": "~2.0.1",
+    "type-is": "~1.6.18",
+    "utils-merge": "1.0.1",
+    "vary": "~1.1.2"
+  },
+  "devDependencies": {
+    "after": "0.8.2",
+    "connect-redis": "3.4.2",
+    "cookie-parser": "1.4.6",
+    "cookie-session": "2.0.0",
+    "ejs": "3.1.9",
+    "eslint": "8.47.0",
+    "express-session": "1.17.2",
+    "hbs": "4.2.0",
+    "marked": "0.7.0",
+    "method-override": "3.0.0",
+    "mocha": "^6.2.2",
+    "morgan": "1.10.0",
+    "nyc": "^14.1.1",
+    "pbkdf2-password": "1.2.1",
+    "supertest": "^6.1.6",
+    "vhost": "~3.0.2"
+  },
+  "engines": {
+    "node": ">= 0.10.0"
+  },
+  "files": [
+    "LICENSE",
+    "History.md",
+    "Readme.md",
+    "index.js",
+    "lib/"
+  ],
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --require test/support/env --reporter spec --bail --check-leaks test/ test/acceptance/",
+    "test-ci": "nyc --exclude examples --exclude test --exclude benchmarks --reporter=lcovonly --reporter=text npm test",
+    "test-cov": "nyc --exclude examples --exclude test --exclude benchmarks --reporter=html --reporter=text npm test",
+    "test-tap": "mocha --require test/support/env --reporter tap --check-leaks test/ test/acceptance/"
+  }
+}
diff --git a/server/node_modules/file-uri-to-path/.npmignore b/server/node_modules/file-uri-to-path/.npmignore
new file mode 100644
index 0000000..07e6e47
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/.npmignore
@@ -0,0 +1 @@
+/node_modules
diff --git a/server/node_modules/file-uri-to-path/.travis.yml b/server/node_modules/file-uri-to-path/.travis.yml
new file mode 100644
index 0000000..016bb6e
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/.travis.yml
@@ -0,0 +1,30 @@
+sudo: false
+
+language: node_js
+
+node_js:
+  - "0.8"
+  - "0.10"
+  - "0.12"
+  - "1"
+  - "2"
+  - "3"
+  - "4"
+  - "5"
+  - "6"
+  - "7"
+  - "8"
+
+install:
+  - PATH="`npm bin`:`npm bin -g`:$PATH"
+  # Node 0.8 comes with a too obsolete npm
+  - if [[ "`node --version`" =~ ^v0\.8\. ]]; then npm install -g npm@1.4.28 ; fi
+  # Install dependencies and build
+  - npm install
+
+script:
+  # Output useful info for debugging
+  - node --version
+  - npm --version
+  # Run tests
+  - npm test
diff --git a/server/node_modules/file-uri-to-path/History.md b/server/node_modules/file-uri-to-path/History.md
new file mode 100644
index 0000000..c8682be
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/History.md
@@ -0,0 +1,21 @@
+
+1.0.0 / 2017-07-06
+==================
+
+  * update "mocha" to v3
+  * fixed unicode URI decoding (#6)
+  * add typings for Typescript
+  * README: use SVG Travis-CI badge
+  * add LICENSE file (MIT)
+  * add .travis.yml file (testing Node.js 0.8 through 8 currently)
+  * add README.md file
+
+0.0.2 / 2014-01-27
+==================
+
+  * index: invert the path separators on Windows
+
+0.0.1 / 2014-01-27
+==================
+
+  * initial commit
diff --git a/server/node_modules/file-uri-to-path/LICENSE b/server/node_modules/file-uri-to-path/LICENSE
new file mode 100644
index 0000000..e1af783
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2014 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/file-uri-to-path/README.md b/server/node_modules/file-uri-to-path/README.md
new file mode 100644
index 0000000..ab30be8
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/README.md
@@ -0,0 +1,74 @@
+file-uri-to-path
+================
+### Convert a `file:` URI to a file path
+[![Build Status](https://travis-ci.org/TooTallNate/file-uri-to-path.svg?branch=master)](https://travis-ci.org/TooTallNate/file-uri-to-path)
+
+Accepts a `file:` URI and returns a regular file path suitable for use with the
+`fs` module functions.
+
+
+Installation
+------------
+
+Install with `npm`:
+
+``` bash
+$ npm install file-uri-to-path
+```
+
+
+Example
+-------
+
+``` js
+var uri2path = require('file-uri-to-path');
+
+uri2path('file://localhost/c|/WINDOWS/clock.avi');
+// "c:\\WINDOWS\\clock.avi"
+
+uri2path('file:///c|/WINDOWS/clock.avi');
+// "c:\\WINDOWS\\clock.avi"
+
+uri2path('file://localhost/c:/WINDOWS/clock.avi');
+// "c:\\WINDOWS\\clock.avi"
+
+uri2path('file://hostname/path/to/the%20file.txt');
+// "\\\\hostname\\path\\to\\the file.txt"
+
+uri2path('file:///c:/path/to/the%20file.txt');
+// "c:\\path\\to\\the file.txt"
+```
+
+
+API
+---
+
+### fileUriToPath(String uri) → String
+
+
+
+License
+-------
+
+(The MIT License)
+
+Copyright (c) 2014 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/file-uri-to-path/index.d.ts b/server/node_modules/file-uri-to-path/index.d.ts
new file mode 100644
index 0000000..99dc3f9
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/index.d.ts
@@ -0,0 +1,2 @@
+declare function fileUriToPath(uri: string): string;
+export = fileUriToPath;
diff --git a/server/node_modules/file-uri-to-path/index.js b/server/node_modules/file-uri-to-path/index.js
new file mode 100644
index 0000000..48cb280
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/index.js
@@ -0,0 +1,66 @@
+
+/**
+ * Module dependencies.
+ */
+
+var sep = require('path').sep || '/';
+
+/**
+ * Module exports.
+ */
+
+module.exports = fileUriToPath;
+
+/**
+ * File URI to Path function.
+ *
+ * @param {String} uri
+ * @return {String} path
+ * @api public
+ */
+
+function fileUriToPath (uri) {
+  if ('string' != typeof uri ||
+      uri.length <= 7 ||
+      'file://' != uri.substring(0, 7)) {
+    throw new TypeError('must pass in a file:// URI to convert to a file path');
+  }
+
+  var rest = decodeURI(uri.substring(7));
+  var firstSlash = rest.indexOf('/');
+  var host = rest.substring(0, firstSlash);
+  var path = rest.substring(firstSlash + 1);
+
+  // 2.  Scheme Definition
+  // As a special case, <host> can be the string "localhost" or the empty
+  // string; this is interpreted as "the machine from which the URL is
+  // being interpreted".
+  if ('localhost' == host) host = '';
+
+  if (host) {
+    host = sep + sep + host;
+  }
+
+  // 3.2  Drives, drive letters, mount points, file system root
+  // Drive letters are mapped into the top of a file URI in various ways,
+  // depending on the implementation; some applications substitute
+  // vertical bar ("|") for the colon after the drive letter, yielding
+  // "file:///c|/tmp/test.txt".  In some cases, the colon is left
+  // unchanged, as in "file:///c:/tmp/test.txt".  In other cases, the
+  // colon is simply omitted, as in "file:///c/tmp/test.txt".
+  path = path.replace(/^(.+)\|/, '$1:');
+
+  // for Windows, we need to invert the path separators from what a URI uses
+  if (sep == '\\') {
+    path = path.replace(/\//g, '\\');
+  }
+
+  if (/^.+\:/.test(path)) {
+    // has Windows drive at beginning of path
+  } else {
+    // unix path…
+    path = sep + path;
+  }
+
+  return host + path;
+}
diff --git a/server/node_modules/file-uri-to-path/package.json b/server/node_modules/file-uri-to-path/package.json
new file mode 100644
index 0000000..b6a4a07
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/package.json
@@ -0,0 +1,32 @@
+{
+  "name": "file-uri-to-path",
+  "version": "1.0.0",
+  "description": "Convert a file: URI to a file path",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "directories": {
+    "test": "test"
+  },
+  "scripts": {
+    "test": "mocha --reporter spec"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/TooTallNate/file-uri-to-path.git"
+  },
+  "keywords": [
+    "file",
+    "uri",
+    "convert",
+    "path"
+  ],
+  "author": "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io/)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/TooTallNate/file-uri-to-path/issues"
+  },
+  "homepage": "https://github.com/TooTallNate/file-uri-to-path",
+  "devDependencies": {
+    "mocha": "3"
+  }
+}
diff --git a/server/node_modules/file-uri-to-path/test/test.js b/server/node_modules/file-uri-to-path/test/test.js
new file mode 100644
index 0000000..79305dc
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/test/test.js
@@ -0,0 +1,24 @@
+
+var sep = require('path').sep || '/';
+var assert = require('assert');
+var uri2path = require('../');
+var tests = require('./tests.json');
+
+describe('file-uri-to-path', function () {
+
+  Object.keys(tests).forEach(function (uri) {
+
+    // the test cases were generated from Windows' PathCreateFromUrlA() function.
+    // On Unix, we have to replace the path separator with the Unix one instead of
+    // the Windows one.
+    var expected = tests[uri].replace(/\\/g, sep);
+
+    it('should convert ' + JSON.stringify(uri) + ' to ' + JSON.stringify(expected),
+    function () {
+      var actual = uri2path(uri);
+      assert.equal(actual, expected);
+    });
+
+  });
+
+});
diff --git a/server/node_modules/file-uri-to-path/test/tests.json b/server/node_modules/file-uri-to-path/test/tests.json
new file mode 100644
index 0000000..b935a63
--- /dev/null
+++ b/server/node_modules/file-uri-to-path/test/tests.json
@@ -0,0 +1,13 @@
+{
+  "file://host/path": "\\\\host\\path",
+  "file://localhost/etc/fstab": "\\etc\\fstab",
+  "file:///etc/fstab": "\\etc\\fstab",
+  "file:///c:/WINDOWS/clock.avi": "c:\\WINDOWS\\clock.avi",
+  "file://localhost/c|/WINDOWS/clock.avi": "c:\\WINDOWS\\clock.avi",
+  "file:///c|/WINDOWS/clock.avi": "c:\\WINDOWS\\clock.avi",
+  "file://localhost/c:/WINDOWS/clock.avi": "c:\\WINDOWS\\clock.avi",
+  "file://hostname/path/to/the%20file.txt": "\\\\hostname\\path\\to\\the file.txt",
+  "file:///c:/path/to/the%20file.txt": "c:\\path\\to\\the file.txt",
+  "file:///C:/Documents%20and%20Settings/davris/FileSchemeURIs.doc": "C:\\Documents and Settings\\davris\\FileSchemeURIs.doc",
+  "file:///C:/caf%C3%A9/%C3%A5r/d%C3%BCnn/%E7%89%9B%E9%93%83/Ph%E1%BB%9F/%F0%9F%98%B5.exe": "C:\\café\\år\\dünn\\牛铃\\Phở\\😵.exe"
+}
diff --git a/server/node_modules/finalhandler/HISTORY.md b/server/node_modules/finalhandler/HISTORY.md
new file mode 100644
index 0000000..77ce54d
--- /dev/null
+++ b/server/node_modules/finalhandler/HISTORY.md
@@ -0,0 +1,216 @@
+v1.3.2 / 2025-12-01
+==================
+
+  * deps: use tilde notation for dependencies
+  * deps: statuses@~2.0.2
+
+v1.3.1 / 2024-09-11
+==================
+
+  * deps: encodeurl@~2.0.0
+
+v1.3.0 / 2024-09-03
+==================
+
+  * ignore status message for HTTP/2 (#53)
+
+v1.2.1 / 2024-09-02
+==================
+
+  * Gracefully handle when handling an error and socket is null
+
+1.2.0 / 2022-03-22
+==================
+
+  * Remove set content headers that break response
+  * deps: on-finished@2.4.1
+  * deps: statuses@2.0.1
+    - Rename `425 Unordered Collection` to standard `425 Too Early`
+
+1.1.2 / 2019-05-09
+==================
+
+  * Set stricter `Content-Security-Policy` header
+  * deps: parseurl@~1.3.3
+  * deps: statuses@~1.5.0
+
+1.1.1 / 2018-03-06
+==================
+
+  * Fix 404 output for bad / missing pathnames
+  * deps: encodeurl@~1.0.2
+    - Fix encoding `%` as last character
+  * deps: statuses@~1.4.0
+
+1.1.0 / 2017-09-24
+==================
+
+  * Use `res.headersSent` when available
+
+1.0.6 / 2017-09-22
+==================
+
+  * deps: debug@2.6.9
+
+1.0.5 / 2017-09-15
+==================
+
+  * deps: parseurl@~1.3.2
+    - perf: reduce overhead for full URLs
+    - perf: unroll the "fast-path" `RegExp`
+
+1.0.4 / 2017-08-03
+==================
+
+  * deps: debug@2.6.8
+
+1.0.3 / 2017-05-16
+==================
+
+  * deps: debug@2.6.7
+    - deps: ms@2.0.0
+
+1.0.2 / 2017-04-22
+==================
+
+  * deps: debug@2.6.4
+    - deps: ms@0.7.3
+
+1.0.1 / 2017-03-21
+==================
+
+  * Fix missing `</html>` in HTML document
+  * deps: debug@2.6.3
+    - Fix: `DEBUG_MAX_ARRAY_LENGTH`
+
+1.0.0 / 2017-02-15
+==================
+
+  * Fix exception when `err` cannot be converted to a string
+  * Fully URL-encode the pathname in the 404 message
+  * Only include the pathname in the 404 message
+  * Send complete HTML document
+  * Set `Content-Security-Policy: default-src 'self'` header
+  * deps: debug@2.6.1
+    - Allow colors in workers
+    - Deprecated `DEBUG_FD` environment variable set to `3` or higher
+    - Fix error when running under React Native
+    - Use same color for same namespace
+    - deps: ms@0.7.2
+
+0.5.1 / 2016-11-12
+==================
+
+  * Fix exception when `err.headers` is not an object
+  * deps: statuses@~1.3.1
+  * perf: hoist regular expressions
+  * perf: remove duplicate validation path
+
+0.5.0 / 2016-06-15
+==================
+
+  * Change invalid or non-numeric status code to 500
+  * Overwrite status message to match set status code
+  * Prefer `err.statusCode` if `err.status` is invalid
+  * Set response headers from `err.headers` object
+  * Use `statuses` instead of `http` module for status messages
+    - Includes all defined status messages
+
+0.4.1 / 2015-12-02
+==================
+
+  * deps: escape-html@~1.0.3
+    - perf: enable strict mode
+    - perf: optimize string replacement
+    - perf: use faster string coercion
+
+0.4.0 / 2015-06-14
+==================
+
+  * Fix a false-positive when unpiping in Node.js 0.8
+  * Support `statusCode` property on `Error` objects
+  * Use `unpipe` module for unpiping requests
+  * deps: escape-html@1.0.2
+  * deps: on-finished@~2.3.0
+    - Add defined behavior for HTTP `CONNECT` requests
+    - Add defined behavior for HTTP `Upgrade` requests
+    - deps: ee-first@1.1.1
+  * perf: enable strict mode
+  * perf: remove argument reassignment
+
+0.3.6 / 2015-05-11
+==================
+
+  * deps: debug@~2.2.0
+    - deps: ms@0.7.1
+
+0.3.5 / 2015-04-22
+==================
+
+  * deps: on-finished@~2.2.1
+    - Fix `isFinished(req)` when data buffered
+
+0.3.4 / 2015-03-15
+==================
+
+  * deps: debug@~2.1.3
+    - Fix high intensity foreground color for bold
+    - deps: ms@0.7.0
+
+0.3.3 / 2015-01-01
+==================
+
+  * deps: debug@~2.1.1
+  * deps: on-finished@~2.2.0
+
+0.3.2 / 2014-10-22
+==================
+
+  * deps: on-finished@~2.1.1
+    - Fix handling of pipelined requests
+
+0.3.1 / 2014-10-16
+==================
+
+  * deps: debug@~2.1.0
+    - Implement `DEBUG_FD` env variable support
+
+0.3.0 / 2014-09-17
+==================
+
+  * Terminate in progress response only on error
+  * Use `on-finished` to determine request status
+
+0.2.0 / 2014-09-03
+==================
+
+  * Set `X-Content-Type-Options: nosniff` header
+  * deps: debug@~2.0.0
+
+0.1.0 / 2014-07-16
+==================
+
+  * Respond after request fully read
+    - prevents hung responses and socket hang ups
+  * deps: debug@1.0.4
+
+0.0.3 / 2014-07-11
+==================
+
+  * deps: debug@1.0.3
+    - Add support for multiple wildcards in namespaces
+
+0.0.2 / 2014-06-19
+==================
+
+  * Handle invalid status codes
+
+0.0.1 / 2014-06-05
+==================
+
+  * deps: debug@1.0.2
+
+0.0.0 / 2014-06-05
+==================
+
+  * Extracted from connect/express
diff --git a/server/node_modules/finalhandler/LICENSE b/server/node_modules/finalhandler/LICENSE
new file mode 100644
index 0000000..6022106
--- /dev/null
+++ b/server/node_modules/finalhandler/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2014-2022 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/finalhandler/README.md b/server/node_modules/finalhandler/README.md
new file mode 100644
index 0000000..6244a13
--- /dev/null
+++ b/server/node_modules/finalhandler/README.md
@@ -0,0 +1,147 @@
+# finalhandler
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][github-actions-ci-image]][github-actions-ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Node.js function to invoke as the final step to respond to HTTP request.
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install finalhandler
+```
+
+## API
+
+```js
+var finalhandler = require('finalhandler')
+```
+
+### finalhandler(req, res, [options])
+
+Returns function to be invoked as the final step for the given `req` and `res`.
+This function is to be invoked as `fn(err)`. If `err` is falsy, the handler will
+write out a 404 response to the `res`. If it is truthy, an error response will
+be written out to the `res` or `res` will be terminated if a response has already
+started.
+
+When an error is written, the following information is added to the response:
+
+  * The `res.statusCode` is set from `err.status` (or `err.statusCode`). If
+    this value is outside the 4xx or 5xx range, it will be set to 500.
+  * The `res.statusMessage` is set according to the status code.
+  * The body will be the HTML of the status code message if `env` is
+    `'production'`, otherwise will be `err.stack`.
+  * Any headers specified in an `err.headers` object.
+
+The final handler will also unpipe anything from `req` when it is invoked.
+
+#### options.env
+
+By default, the environment is determined by `NODE_ENV` variable, but it can be
+overridden by this option.
+
+#### options.onerror
+
+Provide a function to be called with the `err` when it exists. Can be used for
+writing errors to a central location without excessive function generation. Called
+as `onerror(err, req, res)`.
+
+## Examples
+
+### always 404
+
+```js
+var finalhandler = require('finalhandler')
+var http = require('http')
+
+var server = http.createServer(function (req, res) {
+  var done = finalhandler(req, res)
+  done()
+})
+
+server.listen(3000)
+```
+
+### perform simple action
+
+```js
+var finalhandler = require('finalhandler')
+var fs = require('fs')
+var http = require('http')
+
+var server = http.createServer(function (req, res) {
+  var done = finalhandler(req, res)
+
+  fs.readFile('index.html', function (err, buf) {
+    if (err) return done(err)
+    res.setHeader('Content-Type', 'text/html')
+    res.end(buf)
+  })
+})
+
+server.listen(3000)
+```
+
+### use with middleware-style functions
+
+```js
+var finalhandler = require('finalhandler')
+var http = require('http')
+var serveStatic = require('serve-static')
+
+var serve = serveStatic('public')
+
+var server = http.createServer(function (req, res) {
+  var done = finalhandler(req, res)
+  serve(req, res, done)
+})
+
+server.listen(3000)
+```
+
+### keep log of all errors
+
+```js
+var finalhandler = require('finalhandler')
+var fs = require('fs')
+var http = require('http')
+
+var server = http.createServer(function (req, res) {
+  var done = finalhandler(req, res, { onerror: logerror })
+
+  fs.readFile('index.html', function (err, buf) {
+    if (err) return done(err)
+    res.setHeader('Content-Type', 'text/html')
+    res.end(buf)
+  })
+})
+
+server.listen(3000)
+
+function logerror (err) {
+  console.error(err.stack || err.toString())
+}
+```
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/finalhandler.svg
+[npm-url]: https://npmjs.org/package/finalhandler
+[node-image]: https://img.shields.io/node/v/finalhandler.svg
+[node-url]: https://nodejs.org/en/download
+[coveralls-image]: https://img.shields.io/coveralls/pillarjs/finalhandler.svg
+[coveralls-url]: https://coveralls.io/r/pillarjs/finalhandler?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/finalhandler.svg
+[downloads-url]: https://npmjs.org/package/finalhandler
+[github-actions-ci-image]: https://github.com/pillarjs/finalhandler/actions/workflows/ci.yml/badge.svg
+[github-actions-ci-url]: https://github.com/pillarjs/finalhandler/actions/workflows/ci.yml
diff --git a/server/node_modules/finalhandler/SECURITY.md b/server/node_modules/finalhandler/SECURITY.md
new file mode 100644
index 0000000..6e23249
--- /dev/null
+++ b/server/node_modules/finalhandler/SECURITY.md
@@ -0,0 +1,25 @@
+# Security Policies and Procedures
+
+## Reporting a Bug
+
+The `finalhandler` team and community take all security bugs seriously. Thank
+you for improving the security of Express. We appreciate your efforts and
+responsible disclosure and will make every effort to acknowledge your
+contributions.
+
+Report security bugs by emailing the current owner(s) of `finalhandler`. This
+information can be found in the npm registry using the command
+`npm owner ls finalhandler`.
+If unsure or unable to get the information from the above, open an issue
+in the [project issue tracker](https://github.com/pillarjs/finalhandler/issues)
+asking for the current contact information.
+
+To ensure the timely response to your report, please ensure that the entirety
+of the report is contained within the email body and not solely behind a web
+link or an attachment.
+
+At least one owner will acknowledge your email within 48 hours, and will send a
+more detailed response within 48 hours indicating the next steps in handling
+your report. After the initial reply to your report, the owners will
+endeavor to keep you informed of the progress towards a fix and full
+announcement, and may ask for additional information or guidance.
diff --git a/server/node_modules/finalhandler/index.js b/server/node_modules/finalhandler/index.js
new file mode 100644
index 0000000..ec34be9
--- /dev/null
+++ b/server/node_modules/finalhandler/index.js
@@ -0,0 +1,341 @@
+/*!
+ * finalhandler
+ * Copyright(c) 2014-2022 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var debug = require('debug')('finalhandler')
+var encodeUrl = require('encodeurl')
+var escapeHtml = require('escape-html')
+var onFinished = require('on-finished')
+var parseUrl = require('parseurl')
+var statuses = require('statuses')
+var unpipe = require('unpipe')
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var DOUBLE_SPACE_REGEXP = /\x20{2}/g
+var NEWLINE_REGEXP = /\n/g
+
+/* istanbul ignore next */
+var defer = typeof setImmediate === 'function'
+  ? setImmediate
+  : function (fn) { process.nextTick(fn.bind.apply(fn, arguments)) }
+var isFinished = onFinished.isFinished
+
+/**
+ * Create a minimal HTML document.
+ *
+ * @param {string} message
+ * @private
+ */
+
+function createHtmlDocument (message) {
+  var body = escapeHtml(message)
+    .replace(NEWLINE_REGEXP, '<br>')
+    .replace(DOUBLE_SPACE_REGEXP, '  ')
+
+  return '<!DOCTYPE html>\n' +
+    '<html lang="en">\n' +
+    '<head>\n' +
+    '<meta charset="utf-8">\n' +
+    '<title>Error</title>\n' +
+    '</head>\n' +
+    '<body>\n' +
+    '<pre>' + body + '</pre>\n' +
+    '</body>\n' +
+    '</html>\n'
+}
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = finalhandler
+
+/**
+ * Create a function to handle the final response.
+ *
+ * @param {Request} req
+ * @param {Response} res
+ * @param {Object} [options]
+ * @return {Function}
+ * @public
+ */
+
+function finalhandler (req, res, options) {
+  var opts = options || {}
+
+  // get environment
+  var env = opts.env || process.env.NODE_ENV || 'development'
+
+  // get error callback
+  var onerror = opts.onerror
+
+  return function (err) {
+    var headers
+    var msg
+    var status
+
+    // ignore 404 on in-flight response
+    if (!err && headersSent(res)) {
+      debug('cannot 404 after headers sent')
+      return
+    }
+
+    // unhandled error
+    if (err) {
+      // respect status code from error
+      status = getErrorStatusCode(err)
+
+      if (status === undefined) {
+        // fallback to status code on response
+        status = getResponseStatusCode(res)
+      } else {
+        // respect headers from error
+        headers = getErrorHeaders(err)
+      }
+
+      // get error message
+      msg = getErrorMessage(err, status, env)
+    } else {
+      // not found
+      status = 404
+      msg = 'Cannot ' + req.method + ' ' + encodeUrl(getResourceName(req))
+    }
+
+    debug('default %s', status)
+
+    // schedule onerror callback
+    if (err && onerror) {
+      defer(onerror, err, req, res)
+    }
+
+    // cannot actually respond
+    if (headersSent(res)) {
+      debug('cannot %d after headers sent', status)
+      if (req.socket) {
+        req.socket.destroy()
+      }
+      return
+    }
+
+    // send response
+    send(req, res, status, headers, msg)
+  }
+}
+
+/**
+ * Get headers from Error object.
+ *
+ * @param {Error} err
+ * @return {object}
+ * @private
+ */
+
+function getErrorHeaders (err) {
+  if (!err.headers || typeof err.headers !== 'object') {
+    return undefined
+  }
+
+  var headers = Object.create(null)
+  var keys = Object.keys(err.headers)
+
+  for (var i = 0; i < keys.length; i++) {
+    var key = keys[i]
+    headers[key] = err.headers[key]
+  }
+
+  return headers
+}
+
+/**
+ * Get message from Error object, fallback to status message.
+ *
+ * @param {Error} err
+ * @param {number} status
+ * @param {string} env
+ * @return {string}
+ * @private
+ */
+
+function getErrorMessage (err, status, env) {
+  var msg
+
+  if (env !== 'production') {
+    // use err.stack, which typically includes err.message
+    msg = err.stack
+
+    // fallback to err.toString() when possible
+    if (!msg && typeof err.toString === 'function') {
+      msg = err.toString()
+    }
+  }
+
+  return msg || statuses.message[status]
+}
+
+/**
+ * Get status code from Error object.
+ *
+ * @param {Error} err
+ * @return {number}
+ * @private
+ */
+
+function getErrorStatusCode (err) {
+  // check err.status
+  if (typeof err.status === 'number' && err.status >= 400 && err.status < 600) {
+    return err.status
+  }
+
+  // check err.statusCode
+  if (typeof err.statusCode === 'number' && err.statusCode >= 400 && err.statusCode < 600) {
+    return err.statusCode
+  }
+
+  return undefined
+}
+
+/**
+ * Get resource name for the request.
+ *
+ * This is typically just the original pathname of the request
+ * but will fallback to "resource" is that cannot be determined.
+ *
+ * @param {IncomingMessage} req
+ * @return {string}
+ * @private
+ */
+
+function getResourceName (req) {
+  try {
+    return parseUrl.original(req).pathname
+  } catch (e) {
+    return 'resource'
+  }
+}
+
+/**
+ * Get status code from response.
+ *
+ * @param {OutgoingMessage} res
+ * @return {number}
+ * @private
+ */
+
+function getResponseStatusCode (res) {
+  var status = res.statusCode
+
+  // default status code to 500 if outside valid range
+  if (typeof status !== 'number' || status < 400 || status > 599) {
+    status = 500
+  }
+
+  return status
+}
+
+/**
+ * Determine if the response headers have been sent.
+ *
+ * @param {object} res
+ * @returns {boolean}
+ * @private
+ */
+
+function headersSent (res) {
+  return typeof res.headersSent !== 'boolean'
+    ? Boolean(res._header)
+    : res.headersSent
+}
+
+/**
+ * Send response.
+ *
+ * @param {IncomingMessage} req
+ * @param {OutgoingMessage} res
+ * @param {number} status
+ * @param {object} headers
+ * @param {string} message
+ * @private
+ */
+
+function send (req, res, status, headers, message) {
+  function write () {
+    // response body
+    var body = createHtmlDocument(message)
+
+    // response status
+    res.statusCode = status
+
+    if (req.httpVersionMajor < 2) {
+      res.statusMessage = statuses.message[status]
+    }
+
+    // remove any content headers
+    res.removeHeader('Content-Encoding')
+    res.removeHeader('Content-Language')
+    res.removeHeader('Content-Range')
+
+    // response headers
+    setHeaders(res, headers)
+
+    // security headers
+    res.setHeader('Content-Security-Policy', "default-src 'none'")
+    res.setHeader('X-Content-Type-Options', 'nosniff')
+
+    // standard headers
+    res.setHeader('Content-Type', 'text/html; charset=utf-8')
+    res.setHeader('Content-Length', Buffer.byteLength(body, 'utf8'))
+
+    if (req.method === 'HEAD') {
+      res.end()
+      return
+    }
+
+    res.end(body, 'utf8')
+  }
+
+  if (isFinished(req)) {
+    write()
+    return
+  }
+
+  // unpipe everything from the request
+  unpipe(req)
+
+  // flush the request
+  onFinished(req, write)
+  req.resume()
+}
+
+/**
+ * Set response headers from an object.
+ *
+ * @param {OutgoingMessage} res
+ * @param {object} headers
+ * @private
+ */
+
+function setHeaders (res, headers) {
+  if (!headers) {
+    return
+  }
+
+  var keys = Object.keys(headers)
+  for (var i = 0; i < keys.length; i++) {
+    var key = keys[i]
+    res.setHeader(key, headers[key])
+  }
+}
diff --git a/server/node_modules/finalhandler/package.json b/server/node_modules/finalhandler/package.json
new file mode 100644
index 0000000..ce618dc
--- /dev/null
+++ b/server/node_modules/finalhandler/package.json
@@ -0,0 +1,47 @@
+{
+  "name": "finalhandler",
+  "description": "Node.js final http responder",
+  "version": "1.3.2",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "repository": "pillarjs/finalhandler",
+  "dependencies": {
+    "debug": "2.6.9",
+    "encodeurl": "~2.0.0",
+    "escape-html": "~1.0.3",
+    "on-finished": "~2.4.1",
+    "parseurl": "~1.3.3",
+    "statuses": "~2.0.2",
+    "unpipe": "~1.0.0"
+  },
+  "devDependencies": {
+    "eslint": "7.32.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.26.0",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "5.2.0",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "10.0.0",
+    "nyc": "15.1.0",
+    "readable-stream": "2.3.6",
+    "safe-buffer": "5.2.1",
+    "supertest": "6.2.4"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "SECURITY.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --check-leaks test/",
+    "test-ci": "nyc --reporter=lcovonly --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "test-inspect": "mocha --reporter spec --inspect --inspect-brk test/"
+  }
+}
diff --git a/server/node_modules/forwarded/HISTORY.md b/server/node_modules/forwarded/HISTORY.md
new file mode 100644
index 0000000..381e6aa
--- /dev/null
+++ b/server/node_modules/forwarded/HISTORY.md
@@ -0,0 +1,21 @@
+0.2.0 / 2021-05-31
+==================
+
+  * Use `req.socket` over deprecated `req.connection`
+
+0.1.2 / 2017-09-14
+==================
+
+  * perf: improve header parsing
+  * perf: reduce overhead when no `X-Forwarded-For` header
+
+0.1.1 / 2017-09-10
+==================
+
+  * Fix trimming leading / trailing OWS
+  * perf: hoist regular expression
+
+0.1.0 / 2014-09-21
+==================
+
+  * Initial release
diff --git a/server/node_modules/forwarded/LICENSE b/server/node_modules/forwarded/LICENSE
new file mode 100644
index 0000000..84441fb
--- /dev/null
+++ b/server/node_modules/forwarded/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2014-2017 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/forwarded/README.md b/server/node_modules/forwarded/README.md
new file mode 100644
index 0000000..fdd220b
--- /dev/null
+++ b/server/node_modules/forwarded/README.md
@@ -0,0 +1,57 @@
+# forwarded
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][ci-image]][ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Parse HTTP X-Forwarded-For header
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install forwarded
+```
+
+## API
+
+```js
+var forwarded = require('forwarded')
+```
+
+### forwarded(req)
+
+```js
+var addresses = forwarded(req)
+```
+
+Parse the `X-Forwarded-For` header from the request. Returns an array
+of the addresses, including the socket address for the `req`, in reverse
+order (i.e. index `0` is the socket address and the last index is the
+furthest address, typically the end-user).
+
+## Testing
+
+```sh
+$ npm test
+```
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/jshttp/forwarded/master?label=ci
+[ci-url]: https://github.com/jshttp/forwarded/actions?query=workflow%3Aci
+[npm-image]: https://img.shields.io/npm/v/forwarded.svg
+[npm-url]: https://npmjs.org/package/forwarded
+[node-version-image]: https://img.shields.io/node/v/forwarded.svg
+[node-version-url]: https://nodejs.org/en/download/
+[coveralls-image]: https://img.shields.io/coveralls/jshttp/forwarded/master.svg
+[coveralls-url]: https://coveralls.io/r/jshttp/forwarded?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/forwarded.svg
+[downloads-url]: https://npmjs.org/package/forwarded
diff --git a/server/node_modules/forwarded/index.js b/server/node_modules/forwarded/index.js
new file mode 100644
index 0000000..b2b6bdd
--- /dev/null
+++ b/server/node_modules/forwarded/index.js
@@ -0,0 +1,90 @@
+/*!
+ * forwarded
+ * Copyright(c) 2014-2017 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = forwarded
+
+/**
+ * Get all addresses in the request, using the `X-Forwarded-For` header.
+ *
+ * @param {object} req
+ * @return {array}
+ * @public
+ */
+
+function forwarded (req) {
+  if (!req) {
+    throw new TypeError('argument req is required')
+  }
+
+  // simple header parsing
+  var proxyAddrs = parse(req.headers['x-forwarded-for'] || '')
+  var socketAddr = getSocketAddr(req)
+  var addrs = [socketAddr].concat(proxyAddrs)
+
+  // return all addresses
+  return addrs
+}
+
+/**
+ * Get the socket address for a request.
+ *
+ * @param {object} req
+ * @return {string}
+ * @private
+ */
+
+function getSocketAddr (req) {
+  return req.socket
+    ? req.socket.remoteAddress
+    : req.connection.remoteAddress
+}
+
+/**
+ * Parse the X-Forwarded-For header.
+ *
+ * @param {string} header
+ * @private
+ */
+
+function parse (header) {
+  var end = header.length
+  var list = []
+  var start = header.length
+
+  // gather addresses, backwards
+  for (var i = header.length - 1; i >= 0; i--) {
+    switch (header.charCodeAt(i)) {
+      case 0x20: /*   */
+        if (start === end) {
+          start = end = i
+        }
+        break
+      case 0x2c: /* , */
+        if (start !== end) {
+          list.push(header.substring(start, end))
+        }
+        start = end = i
+        break
+      default:
+        start = i
+        break
+    }
+  }
+
+  // final address
+  if (start !== end) {
+    list.push(header.substring(start, end))
+  }
+
+  return list
+}
diff --git a/server/node_modules/forwarded/package.json b/server/node_modules/forwarded/package.json
new file mode 100644
index 0000000..bf9c7d6
--- /dev/null
+++ b/server/node_modules/forwarded/package.json
@@ -0,0 +1,45 @@
+{
+  "name": "forwarded",
+  "description": "Parse HTTP X-Forwarded-For header",
+  "version": "0.2.0",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "x-forwarded-for",
+    "http",
+    "req"
+  ],
+  "repository": "jshttp/forwarded",
+  "devDependencies": {
+    "beautify-benchmark": "0.2.4",
+    "benchmark": "2.1.4",
+    "deep-equal": "1.0.1",
+    "eslint": "7.27.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.23.4",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "4.3.1",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "8.4.0",
+    "nyc": "15.1.0"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  }
+}
diff --git a/server/node_modules/fresh/HISTORY.md b/server/node_modules/fresh/HISTORY.md
new file mode 100644
index 0000000..4586996
--- /dev/null
+++ b/server/node_modules/fresh/HISTORY.md
@@ -0,0 +1,70 @@
+0.5.2 / 2017-09-13
+==================
+
+  * Fix regression matching multiple ETags in `If-None-Match`
+  * perf: improve `If-None-Match` token parsing
+
+0.5.1 / 2017-09-11
+==================
+
+  * Fix handling of modified headers with invalid dates
+  * perf: improve ETag match loop
+
+0.5.0 / 2017-02-21
+==================
+
+  * Fix incorrect result when `If-None-Match` has both `*` and ETags
+  * Fix weak `ETag` matching to match spec
+  * perf: delay reading header values until needed
+  * perf: skip checking modified time if ETag check failed
+  * perf: skip parsing `If-None-Match` when no `ETag` header
+  * perf: use `Date.parse` instead of `new Date`
+
+0.4.0 / 2017-02-05
+==================
+
+  * Fix false detection of `no-cache` request directive
+  * perf: enable strict mode
+  * perf: hoist regular expressions
+  * perf: remove duplicate conditional
+  * perf: remove unnecessary boolean coercions
+
+0.3.0 / 2015-05-12
+==================
+
+  * Add weak `ETag` matching support
+
+0.2.4 / 2014-09-07
+==================
+
+  * Support Node.js 0.6
+
+0.2.3 / 2014-09-07
+==================
+
+  * Move repository to jshttp
+
+0.2.2 / 2014-02-19
+==================
+
+  * Revert "Fix for blank page on Safari reload"
+
+0.2.1 / 2014-01-29
+==================
+
+  * Fix for blank page on Safari reload
+
+0.2.0 / 2013-08-11
+==================
+
+  * Return stale for `Cache-Control: no-cache`
+
+0.1.0 / 2012-06-15
+==================
+
+  * Add `If-None-Match: *` support
+
+0.0.1 / 2012-06-10
+==================
+
+  * Initial release
diff --git a/server/node_modules/fresh/LICENSE b/server/node_modules/fresh/LICENSE
new file mode 100644
index 0000000..1434ade
--- /dev/null
+++ b/server/node_modules/fresh/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2012 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2016-2017 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/fresh/README.md b/server/node_modules/fresh/README.md
new file mode 100644
index 0000000..1c1c680
--- /dev/null
+++ b/server/node_modules/fresh/README.md
@@ -0,0 +1,119 @@
+# fresh
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+HTTP response freshness testing
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```
+$ npm install fresh
+```
+
+## API
+
+
+
+```js
+var fresh = require('fresh')
+```
+
+### fresh(reqHeaders, resHeaders)
+
+Check freshness of the response using request and response headers.
+
+When the response is still "fresh" in the client's cache `true` is
+returned, otherwise `false` is returned to indicate that the client
+cache is now stale and the full response should be sent.
+
+When a client sends the `Cache-Control: no-cache` request header to
+indicate an end-to-end reload request, this module will return `false`
+to make handling these requests transparent.
+
+## Known Issues
+
+This module is designed to only follow the HTTP specifications, not
+to work-around all kinda of client bugs (especially since this module
+typically does not recieve enough information to understand what the
+client actually is).
+
+There is a known issue that in certain versions of Safari, Safari
+will incorrectly make a request that allows this module to validate
+freshness of the resource even when Safari does not have a
+representation of the resource in the cache. The module
+[jumanji](https://www.npmjs.com/package/jumanji) can be used in
+an Express application to work-around this issue and also provides
+links to further reading on this Safari bug.
+
+## Example
+
+### API usage
+
+
+
+```js
+var reqHeaders = { 'if-none-match': '"foo"' }
+var resHeaders = { 'etag': '"bar"' }
+fresh(reqHeaders, resHeaders)
+// => false
+
+var reqHeaders = { 'if-none-match': '"foo"' }
+var resHeaders = { 'etag': '"foo"' }
+fresh(reqHeaders, resHeaders)
+// => true
+```
+
+### Using with Node.js http server
+
+```js
+var fresh = require('fresh')
+var http = require('http')
+
+var server = http.createServer(function (req, res) {
+  // perform server logic
+  // ... including adding ETag / Last-Modified response headers
+
+  if (isFresh(req, res)) {
+    // client has a fresh copy of resource
+    res.statusCode = 304
+    res.end()
+    return
+  }
+
+  // send the resource
+  res.statusCode = 200
+  res.end('hello, world!')
+})
+
+function isFresh (req, res) {
+  return fresh(req.headers, {
+    'etag': res.getHeader('ETag'),
+    'last-modified': res.getHeader('Last-Modified')
+  })
+}
+
+server.listen(3000)
+```
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/fresh.svg
+[npm-url]: https://npmjs.org/package/fresh
+[node-version-image]: https://img.shields.io/node/v/fresh.svg
+[node-version-url]: https://nodejs.org/en/
+[travis-image]: https://img.shields.io/travis/jshttp/fresh/master.svg
+[travis-url]: https://travis-ci.org/jshttp/fresh
+[coveralls-image]: https://img.shields.io/coveralls/jshttp/fresh/master.svg
+[coveralls-url]: https://coveralls.io/r/jshttp/fresh?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/fresh.svg
+[downloads-url]: https://npmjs.org/package/fresh
diff --git a/server/node_modules/fresh/index.js b/server/node_modules/fresh/index.js
new file mode 100644
index 0000000..d154f5a
--- /dev/null
+++ b/server/node_modules/fresh/index.js
@@ -0,0 +1,137 @@
+/*!
+ * fresh
+ * Copyright(c) 2012 TJ Holowaychuk
+ * Copyright(c) 2016-2017 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * RegExp to check for no-cache token in Cache-Control.
+ * @private
+ */
+
+var CACHE_CONTROL_NO_CACHE_REGEXP = /(?:^|,)\s*?no-cache\s*?(?:,|$)/
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = fresh
+
+/**
+ * Check freshness of the response using request and response headers.
+ *
+ * @param {Object} reqHeaders
+ * @param {Object} resHeaders
+ * @return {Boolean}
+ * @public
+ */
+
+function fresh (reqHeaders, resHeaders) {
+  // fields
+  var modifiedSince = reqHeaders['if-modified-since']
+  var noneMatch = reqHeaders['if-none-match']
+
+  // unconditional request
+  if (!modifiedSince && !noneMatch) {
+    return false
+  }
+
+  // Always return stale when Cache-Control: no-cache
+  // to support end-to-end reload requests
+  // https://tools.ietf.org/html/rfc2616#section-14.9.4
+  var cacheControl = reqHeaders['cache-control']
+  if (cacheControl && CACHE_CONTROL_NO_CACHE_REGEXP.test(cacheControl)) {
+    return false
+  }
+
+  // if-none-match
+  if (noneMatch && noneMatch !== '*') {
+    var etag = resHeaders['etag']
+
+    if (!etag) {
+      return false
+    }
+
+    var etagStale = true
+    var matches = parseTokenList(noneMatch)
+    for (var i = 0; i < matches.length; i++) {
+      var match = matches[i]
+      if (match === etag || match === 'W/' + etag || 'W/' + match === etag) {
+        etagStale = false
+        break
+      }
+    }
+
+    if (etagStale) {
+      return false
+    }
+  }
+
+  // if-modified-since
+  if (modifiedSince) {
+    var lastModified = resHeaders['last-modified']
+    var modifiedStale = !lastModified || !(parseHttpDate(lastModified) <= parseHttpDate(modifiedSince))
+
+    if (modifiedStale) {
+      return false
+    }
+  }
+
+  return true
+}
+
+/**
+ * Parse an HTTP Date into a number.
+ *
+ * @param {string} date
+ * @private
+ */
+
+function parseHttpDate (date) {
+  var timestamp = date && Date.parse(date)
+
+  // istanbul ignore next: guard against date.js Date.parse patching
+  return typeof timestamp === 'number'
+    ? timestamp
+    : NaN
+}
+
+/**
+ * Parse a HTTP token list.
+ *
+ * @param {string} str
+ * @private
+ */
+
+function parseTokenList (str) {
+  var end = 0
+  var list = []
+  var start = 0
+
+  // gather tokens
+  for (var i = 0, len = str.length; i < len; i++) {
+    switch (str.charCodeAt(i)) {
+      case 0x20: /*   */
+        if (start === end) {
+          start = end = i + 1
+        }
+        break
+      case 0x2c: /* , */
+        list.push(str.substring(start, end))
+        start = end = i + 1
+        break
+      default:
+        end = i + 1
+        break
+    }
+  }
+
+  // final token
+  list.push(str.substring(start, end))
+
+  return list
+}
diff --git a/server/node_modules/fresh/package.json b/server/node_modules/fresh/package.json
new file mode 100644
index 0000000..c2fa0f4
--- /dev/null
+++ b/server/node_modules/fresh/package.json
@@ -0,0 +1,46 @@
+{
+  "name": "fresh",
+  "description": "HTTP response freshness testing",
+  "version": "0.5.2",
+  "author": "TJ Holowaychuk <tj@vision-media.ca> (http://tjholowaychuk.com)",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "fresh",
+    "http",
+    "conditional",
+    "cache"
+  ],
+  "repository": "jshttp/fresh",
+  "devDependencies": {
+    "beautify-benchmark": "0.2.4",
+    "benchmark": "2.1.4",
+    "eslint": "3.19.0",
+    "eslint-config-standard": "10.2.1",
+    "eslint-plugin-import": "2.7.0",
+    "eslint-plugin-markdown": "1.0.0-beta.6",
+    "eslint-plugin-node": "5.1.1",
+    "eslint-plugin-promise": "3.5.0",
+    "eslint-plugin-standard": "3.0.1",
+    "istanbul": "0.4.5",
+    "mocha": "1.21.5"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  }
+}
diff --git a/server/node_modules/fs-constants/LICENSE b/server/node_modules/fs-constants/LICENSE
new file mode 100644
index 0000000..cb757e5
--- /dev/null
+++ b/server/node_modules/fs-constants/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2018 Mathias Buus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/fs-constants/README.md b/server/node_modules/fs-constants/README.md
new file mode 100644
index 0000000..62b3374
--- /dev/null
+++ b/server/node_modules/fs-constants/README.md
@@ -0,0 +1,26 @@
+# fs-constants
+
+Small module that allows you to get the fs constants across
+Node and the browser. 
+
+```
+npm install fs-constants
+```
+
+Previously you would use `require('constants')` for this in node but that has been
+deprecated and changed to `require('fs').constants` which does not browserify.
+
+This module uses `require('constants')` in the browser and `require('fs').constants` in node to work around this
+
+
+## Usage
+
+``` js
+var constants = require('fs-constants')
+
+console.log('constants:', constants)
+```
+
+## License
+
+MIT
diff --git a/server/node_modules/fs-constants/browser.js b/server/node_modules/fs-constants/browser.js
new file mode 100644
index 0000000..3c87638
--- /dev/null
+++ b/server/node_modules/fs-constants/browser.js
@@ -0,0 +1 @@
+module.exports = require('constants')
diff --git a/server/node_modules/fs-constants/index.js b/server/node_modules/fs-constants/index.js
new file mode 100644
index 0000000..2a3aadf
--- /dev/null
+++ b/server/node_modules/fs-constants/index.js
@@ -0,0 +1 @@
+module.exports = require('fs').constants || require('constants')
diff --git a/server/node_modules/fs-constants/package.json b/server/node_modules/fs-constants/package.json
new file mode 100644
index 0000000..6f2b8f2
--- /dev/null
+++ b/server/node_modules/fs-constants/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "fs-constants",
+  "version": "1.0.0",
+  "description": "Require constants across node and the browser",
+  "main": "index.js",
+  "browser": "browser.js",
+  "dependencies": {},
+  "devDependencies": {},
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/mafintosh/fs-constants.git"
+  },
+  "author": "Mathias Buus (@mafintosh)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/mafintosh/fs-constants/issues"
+  },
+  "homepage": "https://github.com/mafintosh/fs-constants"
+}
diff --git a/server/node_modules/fs-minipass/LICENSE b/server/node_modules/fs-minipass/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/fs-minipass/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/fs-minipass/README.md b/server/node_modules/fs-minipass/README.md
new file mode 100644
index 0000000..1e61241
--- /dev/null
+++ b/server/node_modules/fs-minipass/README.md
@@ -0,0 +1,70 @@
+# fs-minipass
+
+Filesystem streams based on [minipass](http://npm.im/minipass).
+
+4 classes are exported:
+
+- ReadStream
+- ReadStreamSync
+- WriteStream
+- WriteStreamSync
+
+When using `ReadStreamSync`, all of the data is made available
+immediately upon consuming the stream.  Nothing is buffered in memory
+when the stream is constructed.  If the stream is piped to a writer,
+then it will synchronously `read()` and emit data into the writer as
+fast as the writer can consume it.  (That is, it will respect
+backpressure.)  If you call `stream.read()` then it will read the
+entire file and return the contents.
+
+When using `WriteStreamSync`, every write is flushed to the file
+synchronously.  If your writes all come in a single tick, then it'll
+write it all out in a single tick.  It's as synchronous as you are.
+
+The async versions work much like their node builtin counterparts,
+with the exception of introducing significantly less Stream machinery
+overhead.
+
+## USAGE
+
+It's just streams, you pipe them or read() them or write() to them.
+
+```js
+const fsm = require('fs-minipass')
+const readStream = new fsm.ReadStream('file.txt')
+const writeStream = new fsm.WriteStream('output.txt')
+writeStream.write('some file header or whatever\n')
+readStream.pipe(writeStream)
+```
+
+## ReadStream(path, options)
+
+Path string is required, but somewhat irrelevant if an open file
+descriptor is passed in as an option.
+
+Options:
+
+- `fd` Pass in a numeric file descriptor, if the file is already open.
+- `readSize` The size of reads to do, defaults to 16MB
+- `size` The size of the file, if known.  Prevents zero-byte read()
+  call at the end.
+- `autoClose` Set to `false` to prevent the file descriptor from being
+  closed when the file is done being read.
+
+## WriteStream(path, options)
+
+Path string is required, but somewhat irrelevant if an open file
+descriptor is passed in as an option.
+
+Options:
+
+- `fd` Pass in a numeric file descriptor, if the file is already open.
+- `mode` The mode to create the file with. Defaults to `0o666`.
+- `start` The position in the file to start reading.  If not
+  specified, then the file will start writing at position zero, and be
+  truncated by default.
+- `autoClose` Set to `false` to prevent the file descriptor from being
+  closed when the stream is ended.
+- `flags` Flags to use when opening the file.  Irrelevant if `fd` is
+  passed in, since file won't be opened in that case.  Defaults to
+  `'a'` if a `pos` is specified, or `'w'` otherwise.
diff --git a/server/node_modules/fs-minipass/index.js b/server/node_modules/fs-minipass/index.js
new file mode 100644
index 0000000..9b0779c
--- /dev/null
+++ b/server/node_modules/fs-minipass/index.js
@@ -0,0 +1,422 @@
+'use strict'
+const MiniPass = require('minipass')
+const EE = require('events').EventEmitter
+const fs = require('fs')
+
+let writev = fs.writev
+/* istanbul ignore next */
+if (!writev) {
+  // This entire block can be removed if support for earlier than Node.js
+  // 12.9.0 is not needed.
+  const binding = process.binding('fs')
+  const FSReqWrap = binding.FSReqWrap || binding.FSReqCallback
+
+  writev = (fd, iovec, pos, cb) => {
+    const done = (er, bw) => cb(er, bw, iovec)
+    const req = new FSReqWrap()
+    req.oncomplete = done
+    binding.writeBuffers(fd, iovec, pos, req)
+  }
+}
+
+const _autoClose = Symbol('_autoClose')
+const _close = Symbol('_close')
+const _ended = Symbol('_ended')
+const _fd = Symbol('_fd')
+const _finished = Symbol('_finished')
+const _flags = Symbol('_flags')
+const _flush = Symbol('_flush')
+const _handleChunk = Symbol('_handleChunk')
+const _makeBuf = Symbol('_makeBuf')
+const _mode = Symbol('_mode')
+const _needDrain = Symbol('_needDrain')
+const _onerror = Symbol('_onerror')
+const _onopen = Symbol('_onopen')
+const _onread = Symbol('_onread')
+const _onwrite = Symbol('_onwrite')
+const _open = Symbol('_open')
+const _path = Symbol('_path')
+const _pos = Symbol('_pos')
+const _queue = Symbol('_queue')
+const _read = Symbol('_read')
+const _readSize = Symbol('_readSize')
+const _reading = Symbol('_reading')
+const _remain = Symbol('_remain')
+const _size = Symbol('_size')
+const _write = Symbol('_write')
+const _writing = Symbol('_writing')
+const _defaultFlag = Symbol('_defaultFlag')
+const _errored = Symbol('_errored')
+
+class ReadStream extends MiniPass {
+  constructor (path, opt) {
+    opt = opt || {}
+    super(opt)
+
+    this.readable = true
+    this.writable = false
+
+    if (typeof path !== 'string')
+      throw new TypeError('path must be a string')
+
+    this[_errored] = false
+    this[_fd] = typeof opt.fd === 'number' ? opt.fd : null
+    this[_path] = path
+    this[_readSize] = opt.readSize || 16*1024*1024
+    this[_reading] = false
+    this[_size] = typeof opt.size === 'number' ? opt.size : Infinity
+    this[_remain] = this[_size]
+    this[_autoClose] = typeof opt.autoClose === 'boolean' ?
+      opt.autoClose : true
+
+    if (typeof this[_fd] === 'number')
+      this[_read]()
+    else
+      this[_open]()
+  }
+
+  get fd () { return this[_fd] }
+  get path () { return this[_path] }
+
+  write () {
+    throw new TypeError('this is a readable stream')
+  }
+
+  end () {
+    throw new TypeError('this is a readable stream')
+  }
+
+  [_open] () {
+    fs.open(this[_path], 'r', (er, fd) => this[_onopen](er, fd))
+  }
+
+  [_onopen] (er, fd) {
+    if (er)
+      this[_onerror](er)
+    else {
+      this[_fd] = fd
+      this.emit('open', fd)
+      this[_read]()
+    }
+  }
+
+  [_makeBuf] () {
+    return Buffer.allocUnsafe(Math.min(this[_readSize], this[_remain]))
+  }
+
+  [_read] () {
+    if (!this[_reading]) {
+      this[_reading] = true
+      const buf = this[_makeBuf]()
+      /* istanbul ignore if */
+      if (buf.length === 0)
+        return process.nextTick(() => this[_onread](null, 0, buf))
+      fs.read(this[_fd], buf, 0, buf.length, null, (er, br, buf) =>
+        this[_onread](er, br, buf))
+    }
+  }
+
+  [_onread] (er, br, buf) {
+    this[_reading] = false
+    if (er)
+      this[_onerror](er)
+    else if (this[_handleChunk](br, buf))
+      this[_read]()
+  }
+
+  [_close] () {
+    if (this[_autoClose] && typeof this[_fd] === 'number') {
+      const fd = this[_fd]
+      this[_fd] = null
+      fs.close(fd, er => er ? this.emit('error', er) : this.emit('close'))
+    }
+  }
+
+  [_onerror] (er) {
+    this[_reading] = true
+    this[_close]()
+    this.emit('error', er)
+  }
+
+  [_handleChunk] (br, buf) {
+    let ret = false
+    // no effect if infinite
+    this[_remain] -= br
+    if (br > 0)
+      ret = super.write(br < buf.length ? buf.slice(0, br) : buf)
+
+    if (br === 0 || this[_remain] <= 0) {
+      ret = false
+      this[_close]()
+      super.end()
+    }
+
+    return ret
+  }
+
+  emit (ev, data) {
+    switch (ev) {
+      case 'prefinish':
+      case 'finish':
+        break
+
+      case 'drain':
+        if (typeof this[_fd] === 'number')
+          this[_read]()
+        break
+
+      case 'error':
+        if (this[_errored])
+          return
+        this[_errored] = true
+        return super.emit(ev, data)
+
+      default:
+        return super.emit(ev, data)
+    }
+  }
+}
+
+class ReadStreamSync extends ReadStream {
+  [_open] () {
+    let threw = true
+    try {
+      this[_onopen](null, fs.openSync(this[_path], 'r'))
+      threw = false
+    } finally {
+      if (threw)
+        this[_close]()
+    }
+  }
+
+  [_read] () {
+    let threw = true
+    try {
+      if (!this[_reading]) {
+        this[_reading] = true
+        do {
+          const buf = this[_makeBuf]()
+          /* istanbul ignore next */
+          const br = buf.length === 0 ? 0
+            : fs.readSync(this[_fd], buf, 0, buf.length, null)
+          if (!this[_handleChunk](br, buf))
+            break
+        } while (true)
+        this[_reading] = false
+      }
+      threw = false
+    } finally {
+      if (threw)
+        this[_close]()
+    }
+  }
+
+  [_close] () {
+    if (this[_autoClose] && typeof this[_fd] === 'number') {
+      const fd = this[_fd]
+      this[_fd] = null
+      fs.closeSync(fd)
+      this.emit('close')
+    }
+  }
+}
+
+class WriteStream extends EE {
+  constructor (path, opt) {
+    opt = opt || {}
+    super(opt)
+    this.readable = false
+    this.writable = true
+    this[_errored] = false
+    this[_writing] = false
+    this[_ended] = false
+    this[_needDrain] = false
+    this[_queue] = []
+    this[_path] = path
+    this[_fd] = typeof opt.fd === 'number' ? opt.fd : null
+    this[_mode] = opt.mode === undefined ? 0o666 : opt.mode
+    this[_pos] = typeof opt.start === 'number' ? opt.start : null
+    this[_autoClose] = typeof opt.autoClose === 'boolean' ?
+      opt.autoClose : true
+
+    // truncating makes no sense when writing into the middle
+    const defaultFlag = this[_pos] !== null ? 'r+' : 'w'
+    this[_defaultFlag] = opt.flags === undefined
+    this[_flags] = this[_defaultFlag] ? defaultFlag : opt.flags
+
+    if (this[_fd] === null)
+      this[_open]()
+  }
+
+  emit (ev, data) {
+    if (ev === 'error') {
+      if (this[_errored])
+        return
+      this[_errored] = true
+    }
+    return super.emit(ev, data)
+  }
+
+
+  get fd () { return this[_fd] }
+  get path () { return this[_path] }
+
+  [_onerror] (er) {
+    this[_close]()
+    this[_writing] = true
+    this.emit('error', er)
+  }
+
+  [_open] () {
+    fs.open(this[_path], this[_flags], this[_mode],
+      (er, fd) => this[_onopen](er, fd))
+  }
+
+  [_onopen] (er, fd) {
+    if (this[_defaultFlag] &&
+        this[_flags] === 'r+' &&
+        er && er.code === 'ENOENT') {
+      this[_flags] = 'w'
+      this[_open]()
+    } else if (er)
+      this[_onerror](er)
+    else {
+      this[_fd] = fd
+      this.emit('open', fd)
+      this[_flush]()
+    }
+  }
+
+  end (buf, enc) {
+    if (buf)
+      this.write(buf, enc)
+
+    this[_ended] = true
+
+    // synthetic after-write logic, where drain/finish live
+    if (!this[_writing] && !this[_queue].length &&
+        typeof this[_fd] === 'number')
+      this[_onwrite](null, 0)
+    return this
+  }
+
+  write (buf, enc) {
+    if (typeof buf === 'string')
+      buf = Buffer.from(buf, enc)
+
+    if (this[_ended]) {
+      this.emit('error', new Error('write() after end()'))
+      return false
+    }
+
+    if (this[_fd] === null || this[_writing] || this[_queue].length) {
+      this[_queue].push(buf)
+      this[_needDrain] = true
+      return false
+    }
+
+    this[_writing] = true
+    this[_write](buf)
+    return true
+  }
+
+  [_write] (buf) {
+    fs.write(this[_fd], buf, 0, buf.length, this[_pos], (er, bw) =>
+      this[_onwrite](er, bw))
+  }
+
+  [_onwrite] (er, bw) {
+    if (er)
+      this[_onerror](er)
+    else {
+      if (this[_pos] !== null)
+        this[_pos] += bw
+      if (this[_queue].length)
+        this[_flush]()
+      else {
+        this[_writing] = false
+
+        if (this[_ended] && !this[_finished]) {
+          this[_finished] = true
+          this[_close]()
+          this.emit('finish')
+        } else if (this[_needDrain]) {
+          this[_needDrain] = false
+          this.emit('drain')
+        }
+      }
+    }
+  }
+
+  [_flush] () {
+    if (this[_queue].length === 0) {
+      if (this[_ended])
+        this[_onwrite](null, 0)
+    } else if (this[_queue].length === 1)
+      this[_write](this[_queue].pop())
+    else {
+      const iovec = this[_queue]
+      this[_queue] = []
+      writev(this[_fd], iovec, this[_pos],
+        (er, bw) => this[_onwrite](er, bw))
+    }
+  }
+
+  [_close] () {
+    if (this[_autoClose] && typeof this[_fd] === 'number') {
+      const fd = this[_fd]
+      this[_fd] = null
+      fs.close(fd, er => er ? this.emit('error', er) : this.emit('close'))
+    }
+  }
+}
+
+class WriteStreamSync extends WriteStream {
+  [_open] () {
+    let fd
+    // only wrap in a try{} block if we know we'll retry, to avoid
+    // the rethrow obscuring the error's source frame in most cases.
+    if (this[_defaultFlag] && this[_flags] === 'r+') {
+      try {
+        fd = fs.openSync(this[_path], this[_flags], this[_mode])
+      } catch (er) {
+        if (er.code === 'ENOENT') {
+          this[_flags] = 'w'
+          return this[_open]()
+        } else
+          throw er
+      }
+    } else
+      fd = fs.openSync(this[_path], this[_flags], this[_mode])
+
+    this[_onopen](null, fd)
+  }
+
+  [_close] () {
+    if (this[_autoClose] && typeof this[_fd] === 'number') {
+      const fd = this[_fd]
+      this[_fd] = null
+      fs.closeSync(fd)
+      this.emit('close')
+    }
+  }
+
+  [_write] (buf) {
+    // throw the original, but try to close if it fails
+    let threw = true
+    try {
+      this[_onwrite](null,
+        fs.writeSync(this[_fd], buf, 0, buf.length, this[_pos]))
+      threw = false
+    } finally {
+      if (threw)
+        try { this[_close]() } catch (_) {}
+    }
+  }
+}
+
+exports.ReadStream = ReadStream
+exports.ReadStreamSync = ReadStreamSync
+
+exports.WriteStream = WriteStream
+exports.WriteStreamSync = WriteStreamSync
diff --git a/server/node_modules/fs-minipass/package.json b/server/node_modules/fs-minipass/package.json
new file mode 100644
index 0000000..2f2436c
--- /dev/null
+++ b/server/node_modules/fs-minipass/package.json
@@ -0,0 +1,39 @@
+{
+  "name": "fs-minipass",
+  "version": "2.1.0",
+  "main": "index.js",
+  "scripts": {
+    "test": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "keywords": [],
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/npm/fs-minipass.git"
+  },
+  "bugs": {
+    "url": "https://github.com/npm/fs-minipass/issues"
+  },
+  "homepage": "https://github.com/npm/fs-minipass#readme",
+  "description": "fs read and write streams based on minipass",
+  "dependencies": {
+    "minipass": "^3.0.0"
+  },
+  "devDependencies": {
+    "mutate-fs": "^2.0.1",
+    "tap": "^14.6.4"
+  },
+  "files": [
+    "index.js"
+  ],
+  "tap": {
+    "check-coverage": true
+  },
+  "engines": {
+    "node": ">= 8"
+  }
+}
diff --git a/server/node_modules/fs.realpath/LICENSE b/server/node_modules/fs.realpath/LICENSE
new file mode 100644
index 0000000..5bd884c
--- /dev/null
+++ b/server/node_modules/fs.realpath/LICENSE
@@ -0,0 +1,43 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+----
+
+This library bundles a version of the `fs.realpath` and `fs.realpathSync`
+methods from Node.js v0.10 under the terms of the Node.js MIT license.
+
+Node's license follows, also included at the header of `old.js` which contains
+the licensed code:
+
+  Copyright Joyent, Inc. and other Node contributors.
+
+  Permission is hereby granted, free of charge, to any person obtaining a
+  copy of this software and associated documentation files (the "Software"),
+  to deal in the Software without restriction, including without limitation
+  the rights to use, copy, modify, merge, publish, distribute, sublicense,
+  and/or sell copies of the Software, and to permit persons to whom the
+  Software is furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+  DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/fs.realpath/README.md b/server/node_modules/fs.realpath/README.md
new file mode 100644
index 0000000..a42ceac
--- /dev/null
+++ b/server/node_modules/fs.realpath/README.md
@@ -0,0 +1,33 @@
+# fs.realpath
+
+A backwards-compatible fs.realpath for Node v6 and above
+
+In Node v6, the JavaScript implementation of fs.realpath was replaced
+with a faster (but less resilient) native implementation.  That raises
+new and platform-specific errors and cannot handle long or excessively
+symlink-looping paths.
+
+This module handles those cases by detecting the new errors and
+falling back to the JavaScript implementation.  On versions of Node
+prior to v6, it has no effect.
+
+## USAGE
+
+```js
+var rp = require('fs.realpath')
+
+// async version
+rp.realpath(someLongAndLoopingPath, function (er, real) {
+  // the ELOOP was handled, but it was a bit slower
+})
+
+// sync version
+var real = rp.realpathSync(someLongAndLoopingPath)
+
+// monkeypatch at your own risk!
+// This replaces the fs.realpath/fs.realpathSync builtins
+rp.monkeypatch()
+
+// un-do the monkeypatching
+rp.unmonkeypatch()
+```
diff --git a/server/node_modules/fs.realpath/index.js b/server/node_modules/fs.realpath/index.js
new file mode 100644
index 0000000..b09c7c7
--- /dev/null
+++ b/server/node_modules/fs.realpath/index.js
@@ -0,0 +1,66 @@
+module.exports = realpath
+realpath.realpath = realpath
+realpath.sync = realpathSync
+realpath.realpathSync = realpathSync
+realpath.monkeypatch = monkeypatch
+realpath.unmonkeypatch = unmonkeypatch
+
+var fs = require('fs')
+var origRealpath = fs.realpath
+var origRealpathSync = fs.realpathSync
+
+var version = process.version
+var ok = /^v[0-5]\./.test(version)
+var old = require('./old.js')
+
+function newError (er) {
+  return er && er.syscall === 'realpath' && (
+    er.code === 'ELOOP' ||
+    er.code === 'ENOMEM' ||
+    er.code === 'ENAMETOOLONG'
+  )
+}
+
+function realpath (p, cache, cb) {
+  if (ok) {
+    return origRealpath(p, cache, cb)
+  }
+
+  if (typeof cache === 'function') {
+    cb = cache
+    cache = null
+  }
+  origRealpath(p, cache, function (er, result) {
+    if (newError(er)) {
+      old.realpath(p, cache, cb)
+    } else {
+      cb(er, result)
+    }
+  })
+}
+
+function realpathSync (p, cache) {
+  if (ok) {
+    return origRealpathSync(p, cache)
+  }
+
+  try {
+    return origRealpathSync(p, cache)
+  } catch (er) {
+    if (newError(er)) {
+      return old.realpathSync(p, cache)
+    } else {
+      throw er
+    }
+  }
+}
+
+function monkeypatch () {
+  fs.realpath = realpath
+  fs.realpathSync = realpathSync
+}
+
+function unmonkeypatch () {
+  fs.realpath = origRealpath
+  fs.realpathSync = origRealpathSync
+}
diff --git a/server/node_modules/fs.realpath/old.js b/server/node_modules/fs.realpath/old.js
new file mode 100644
index 0000000..b40305e
--- /dev/null
+++ b/server/node_modules/fs.realpath/old.js
@@ -0,0 +1,303 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var pathModule = require('path');
+var isWindows = process.platform === 'win32';
+var fs = require('fs');
+
+// JavaScript implementation of realpath, ported from node pre-v6
+
+var DEBUG = process.env.NODE_DEBUG && /fs/.test(process.env.NODE_DEBUG);
+
+function rethrow() {
+  // Only enable in debug mode. A backtrace uses ~1000 bytes of heap space and
+  // is fairly slow to generate.
+  var callback;
+  if (DEBUG) {
+    var backtrace = new Error;
+    callback = debugCallback;
+  } else
+    callback = missingCallback;
+
+  return callback;
+
+  function debugCallback(err) {
+    if (err) {
+      backtrace.message = err.message;
+      err = backtrace;
+      missingCallback(err);
+    }
+  }
+
+  function missingCallback(err) {
+    if (err) {
+      if (process.throwDeprecation)
+        throw err;  // Forgot a callback but don't know where? Use NODE_DEBUG=fs
+      else if (!process.noDeprecation) {
+        var msg = 'fs: missing callback ' + (err.stack || err.message);
+        if (process.traceDeprecation)
+          console.trace(msg);
+        else
+          console.error(msg);
+      }
+    }
+  }
+}
+
+function maybeCallback(cb) {
+  return typeof cb === 'function' ? cb : rethrow();
+}
+
+var normalize = pathModule.normalize;
+
+// Regexp that finds the next partion of a (partial) path
+// result is [base_with_slash, base], e.g. ['somedir/', 'somedir']
+if (isWindows) {
+  var nextPartRe = /(.*?)(?:[\/\\]+|$)/g;
+} else {
+  var nextPartRe = /(.*?)(?:[\/]+|$)/g;
+}
+
+// Regex to find the device root, including trailing slash. E.g. 'c:\\'.
+if (isWindows) {
+  var splitRootRe = /^(?:[a-zA-Z]:|[\\\/]{2}[^\\\/]+[\\\/][^\\\/]+)?[\\\/]*/;
+} else {
+  var splitRootRe = /^[\/]*/;
+}
+
+exports.realpathSync = function realpathSync(p, cache) {
+  // make p is absolute
+  p = pathModule.resolve(p);
+
+  if (cache && Object.prototype.hasOwnProperty.call(cache, p)) {
+    return cache[p];
+  }
+
+  var original = p,
+      seenLinks = {},
+      knownHard = {};
+
+  // current character position in p
+  var pos;
+  // the partial path so far, including a trailing slash if any
+  var current;
+  // the partial path without a trailing slash (except when pointing at a root)
+  var base;
+  // the partial path scanned in the previous round, with slash
+  var previous;
+
+  start();
+
+  function start() {
+    // Skip over roots
+    var m = splitRootRe.exec(p);
+    pos = m[0].length;
+    current = m[0];
+    base = m[0];
+    previous = '';
+
+    // On windows, check that the root exists. On unix there is no need.
+    if (isWindows && !knownHard[base]) {
+      fs.lstatSync(base);
+      knownHard[base] = true;
+    }
+  }
+
+  // walk down the path, swapping out linked pathparts for their real
+  // values
+  // NB: p.length changes.
+  while (pos < p.length) {
+    // find the next part
+    nextPartRe.lastIndex = pos;
+    var result = nextPartRe.exec(p);
+    previous = current;
+    current += result[0];
+    base = previous + result[1];
+    pos = nextPartRe.lastIndex;
+
+    // continue if not a symlink
+    if (knownHard[base] || (cache && cache[base] === base)) {
+      continue;
+    }
+
+    var resolvedLink;
+    if (cache && Object.prototype.hasOwnProperty.call(cache, base)) {
+      // some known symbolic link.  no need to stat again.
+      resolvedLink = cache[base];
+    } else {
+      var stat = fs.lstatSync(base);
+      if (!stat.isSymbolicLink()) {
+        knownHard[base] = true;
+        if (cache) cache[base] = base;
+        continue;
+      }
+
+      // read the link if it wasn't read before
+      // dev/ino always return 0 on windows, so skip the check.
+      var linkTarget = null;
+      if (!isWindows) {
+        var id = stat.dev.toString(32) + ':' + stat.ino.toString(32);
+        if (seenLinks.hasOwnProperty(id)) {
+          linkTarget = seenLinks[id];
+        }
+      }
+      if (linkTarget === null) {
+        fs.statSync(base);
+        linkTarget = fs.readlinkSync(base);
+      }
+      resolvedLink = pathModule.resolve(previous, linkTarget);
+      // track this, if given a cache.
+      if (cache) cache[base] = resolvedLink;
+      if (!isWindows) seenLinks[id] = linkTarget;
+    }
+
+    // resolve the link, then start over
+    p = pathModule.resolve(resolvedLink, p.slice(pos));
+    start();
+  }
+
+  if (cache) cache[original] = p;
+
+  return p;
+};
+
+
+exports.realpath = function realpath(p, cache, cb) {
+  if (typeof cb !== 'function') {
+    cb = maybeCallback(cache);
+    cache = null;
+  }
+
+  // make p is absolute
+  p = pathModule.resolve(p);
+
+  if (cache && Object.prototype.hasOwnProperty.call(cache, p)) {
+    return process.nextTick(cb.bind(null, null, cache[p]));
+  }
+
+  var original = p,
+      seenLinks = {},
+      knownHard = {};
+
+  // current character position in p
+  var pos;
+  // the partial path so far, including a trailing slash if any
+  var current;
+  // the partial path without a trailing slash (except when pointing at a root)
+  var base;
+  // the partial path scanned in the previous round, with slash
+  var previous;
+
+  start();
+
+  function start() {
+    // Skip over roots
+    var m = splitRootRe.exec(p);
+    pos = m[0].length;
+    current = m[0];
+    base = m[0];
+    previous = '';
+
+    // On windows, check that the root exists. On unix there is no need.
+    if (isWindows && !knownHard[base]) {
+      fs.lstat(base, function(err) {
+        if (err) return cb(err);
+        knownHard[base] = true;
+        LOOP();
+      });
+    } else {
+      process.nextTick(LOOP);
+    }
+  }
+
+  // walk down the path, swapping out linked pathparts for their real
+  // values
+  function LOOP() {
+    // stop if scanned past end of path
+    if (pos >= p.length) {
+      if (cache) cache[original] = p;
+      return cb(null, p);
+    }
+
+    // find the next part
+    nextPartRe.lastIndex = pos;
+    var result = nextPartRe.exec(p);
+    previous = current;
+    current += result[0];
+    base = previous + result[1];
+    pos = nextPartRe.lastIndex;
+
+    // continue if not a symlink
+    if (knownHard[base] || (cache && cache[base] === base)) {
+      return process.nextTick(LOOP);
+    }
+
+    if (cache && Object.prototype.hasOwnProperty.call(cache, base)) {
+      // known symbolic link.  no need to stat again.
+      return gotResolvedLink(cache[base]);
+    }
+
+    return fs.lstat(base, gotStat);
+  }
+
+  function gotStat(err, stat) {
+    if (err) return cb(err);
+
+    // if not a symlink, skip to the next path part
+    if (!stat.isSymbolicLink()) {
+      knownHard[base] = true;
+      if (cache) cache[base] = base;
+      return process.nextTick(LOOP);
+    }
+
+    // stat & read the link if not read before
+    // call gotTarget as soon as the link target is known
+    // dev/ino always return 0 on windows, so skip the check.
+    if (!isWindows) {
+      var id = stat.dev.toString(32) + ':' + stat.ino.toString(32);
+      if (seenLinks.hasOwnProperty(id)) {
+        return gotTarget(null, seenLinks[id], base);
+      }
+    }
+    fs.stat(base, function(err) {
+      if (err) return cb(err);
+
+      fs.readlink(base, function(err, target) {
+        if (!isWindows) seenLinks[id] = target;
+        gotTarget(err, target);
+      });
+    });
+  }
+
+  function gotTarget(err, target, base) {
+    if (err) return cb(err);
+
+    var resolvedLink = pathModule.resolve(previous, target);
+    if (cache) cache[base] = resolvedLink;
+    gotResolvedLink(resolvedLink);
+  }
+
+  function gotResolvedLink(resolvedLink) {
+    // resolve the link, then start over
+    p = pathModule.resolve(resolvedLink, p.slice(pos));
+    start();
+  }
+};
diff --git a/server/node_modules/fs.realpath/package.json b/server/node_modules/fs.realpath/package.json
new file mode 100644
index 0000000..3edc57d
--- /dev/null
+++ b/server/node_modules/fs.realpath/package.json
@@ -0,0 +1,26 @@
+{
+  "name": "fs.realpath",
+  "version": "1.0.0",
+  "description": "Use node's fs.realpath, but fall back to the JS implementation if the native one fails",
+  "main": "index.js",
+  "dependencies": {},
+  "devDependencies": {},
+  "scripts": {
+    "test": "tap test/*.js --cov"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/isaacs/fs.realpath.git"
+  },
+  "keywords": [
+    "realpath",
+    "fs",
+    "polyfill"
+  ],
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC",
+  "files": [
+    "old.js",
+    "index.js"
+  ]
+}
diff --git a/server/node_modules/function-bind/.eslintrc b/server/node_modules/function-bind/.eslintrc
new file mode 100644
index 0000000..71a054f
--- /dev/null
+++ b/server/node_modules/function-bind/.eslintrc
@@ -0,0 +1,21 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"func-name-matching": 0,
+		"indent": [2, 4],
+		"no-new-func": [1],
+	},
+
+	"overrides": [
+		{
+			"files": "test/**",
+			"rules": {
+				"max-lines-per-function": 0,
+				"strict": [0]
+			},
+		},
+	],
+}
diff --git a/server/node_modules/function-bind/.github/FUNDING.yml b/server/node_modules/function-bind/.github/FUNDING.yml
new file mode 100644
index 0000000..7448219
--- /dev/null
+++ b/server/node_modules/function-bind/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/function-bind
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/function-bind/.github/SECURITY.md b/server/node_modules/function-bind/.github/SECURITY.md
new file mode 100644
index 0000000..82e4285
--- /dev/null
+++ b/server/node_modules/function-bind/.github/SECURITY.md
@@ -0,0 +1,3 @@
+# Security
+
+Please email [@ljharb](https://github.com/ljharb) or see https://tidelift.com/security if you have a potential security vulnerability to report.
diff --git a/server/node_modules/function-bind/.nycrc b/server/node_modules/function-bind/.nycrc
new file mode 100644
index 0000000..1826526
--- /dev/null
+++ b/server/node_modules/function-bind/.nycrc
@@ -0,0 +1,13 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"lines": 86,
+	"statements": 85.93,
+	"functions": 82.43,
+	"branches": 76.06,
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/function-bind/CHANGELOG.md b/server/node_modules/function-bind/CHANGELOG.md
new file mode 100644
index 0000000..f9e6cc0
--- /dev/null
+++ b/server/node_modules/function-bind/CHANGELOG.md
@@ -0,0 +1,136 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.1.2](https://github.com/ljharb/function-bind/compare/v1.1.1...v1.1.2) - 2023-10-12
+
+### Merged
+
+- Point to the correct file [`#16`](https://github.com/ljharb/function-bind/pull/16)
+
+### Commits
+
+- [Tests] migrate tests to Github Actions [`4f8b57c`](https://github.com/ljharb/function-bind/commit/4f8b57c02f2011fe9ae353d5e74e8745f0988af8)
+- [Tests] remove `jscs` [`90eb2ed`](https://github.com/ljharb/function-bind/commit/90eb2edbeefd5b76cd6c3a482ea3454db169b31f)
+- [meta] update `.gitignore` [`53fcdc3`](https://github.com/ljharb/function-bind/commit/53fcdc371cd66634d6e9b71c836a50f437e89fed)
+- [Tests] up to `node` `v11.10`, `v10.15`, `v9.11`, `v8.15`, `v6.16`, `v4.9`; use `nvm install-latest-npm`; run audit script in tests [`1fe8f6e`](https://github.com/ljharb/function-bind/commit/1fe8f6e9aed0dfa8d8b3cdbd00c7f5ea0cd2b36e)
+- [meta] add `auto-changelog` [`1921fcb`](https://github.com/ljharb/function-bind/commit/1921fcb5b416b63ffc4acad051b6aad5722f777d)
+- [Robustness] remove runtime dependency on all builtins except `.apply` [`f743e61`](https://github.com/ljharb/function-bind/commit/f743e61aa6bb2360358c04d4884c9db853d118b7)
+- Docs: enable badges; update wording [`503cb12`](https://github.com/ljharb/function-bind/commit/503cb12d998b5f91822776c73332c7adcd6355dd)
+- [readme] update badges [`290c5db`](https://github.com/ljharb/function-bind/commit/290c5dbbbda7264efaeb886552a374b869a4bb48)
+- [Tests] switch to nyc for coverage [`ea360ba`](https://github.com/ljharb/function-bind/commit/ea360ba907fc2601ed18d01a3827fa2d3533cdf8)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `tape` [`cae5e9e`](https://github.com/ljharb/function-bind/commit/cae5e9e07a5578dc6df26c03ee22851ce05b943c)
+- [meta] add `funding` field; create FUNDING.yml [`c9f4274`](https://github.com/ljharb/function-bind/commit/c9f4274aa80ea3aae9657a3938fdba41a3b04ca6)
+- [Tests] fix eslint errors from #15 [`f69aaa2`](https://github.com/ljharb/function-bind/commit/f69aaa2beb2fdab4415bfb885760a699d0b9c964)
+- [actions] fix permissions [`99a0cd9`](https://github.com/ljharb/function-bind/commit/99a0cd9f3b5bac223a0d572f081834cd73314be7)
+- [meta] use `npmignore` to autogenerate an npmignore file [`f03b524`](https://github.com/ljharb/function-bind/commit/f03b524ca91f75a109a5d062f029122c86ecd1ae)
+- [Dev Deps] update `@ljharb/eslint‑config`, `eslint`, `tape` [`7af9300`](https://github.com/ljharb/function-bind/commit/7af930023ae2ce7645489532821e4fbbcd7a2280)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `covert`, `tape` [`64a9127`](https://github.com/ljharb/function-bind/commit/64a9127ab0bd331b93d6572eaf6e9971967fc08c)
+- [Tests] use `aud` instead of `npm audit` [`e75069c`](https://github.com/ljharb/function-bind/commit/e75069c50010a8fcce2a9ce2324934c35fdb4386)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud`, `tape` [`d03555c`](https://github.com/ljharb/function-bind/commit/d03555ca59dea3b71ce710045e4303b9e2619e28)
+- [meta] add `safe-publish-latest` [`9c8f809`](https://github.com/ljharb/function-bind/commit/9c8f8092aed027d7e80c94f517aa892385b64f09)
+- [Dev Deps] update `@ljharb/eslint-config`, `tape` [`baf6893`](https://github.com/ljharb/function-bind/commit/baf6893e27f5b59abe88bc1995e6f6ed1e527397)
+- [meta] create SECURITY.md [`4db1779`](https://github.com/ljharb/function-bind/commit/4db17799f1f28ae294cb95e0081ca2b591c3911b)
+- [Tests] add `npm run audit` [`c8b38ec`](https://github.com/ljharb/function-bind/commit/c8b38ec40ed3f85dabdee40ed4148f1748375bc2)
+- Revert "Point to the correct file" [`05cdf0f`](https://github.com/ljharb/function-bind/commit/05cdf0fa205c6a3c5ba40bbedd1dfa9874f915c9)
+
+## [v1.1.1](https://github.com/ljharb/function-bind/compare/v1.1.0...v1.1.1) - 2017-08-28
+
+### Commits
+
+- [Tests] up to `node` `v8`; newer npm breaks on older node; fix scripts [`817f7d2`](https://github.com/ljharb/function-bind/commit/817f7d28470fdbff8ef608d4d565dd4d1430bc5e)
+- [Dev Deps] update `eslint`, `jscs`, `tape`, `@ljharb/eslint-config` [`854288b`](https://github.com/ljharb/function-bind/commit/854288b1b6f5c555f89aceb9eff1152510262084)
+- [Dev Deps] update `tape`, `jscs`, `eslint`, `@ljharb/eslint-config` [`83e639f`](https://github.com/ljharb/function-bind/commit/83e639ff74e6cd6921285bccec22c1bcf72311bd)
+- Only apps should have lockfiles [`5ed97f5`](https://github.com/ljharb/function-bind/commit/5ed97f51235c17774e0832e122abda0f3229c908)
+- Use a SPDX-compliant “license” field. [`5feefea`](https://github.com/ljharb/function-bind/commit/5feefea0dc0193993e83e5df01ded424403a5381)
+
+## [v1.1.0](https://github.com/ljharb/function-bind/compare/v1.0.2...v1.1.0) - 2016-02-14
+
+### Commits
+
+- Update `eslint`, `tape`; use my personal shared `eslint` config [`9c9062a`](https://github.com/ljharb/function-bind/commit/9c9062abbe9dd70b59ea2c3a3c3a81f29b457097)
+- Add `npm run eslint` [`dd96c56`](https://github.com/ljharb/function-bind/commit/dd96c56720034a3c1ffee10b8a59a6f7c53e24ad)
+- [New] return the native `bind` when available. [`82186e0`](https://github.com/ljharb/function-bind/commit/82186e03d73e580f95ff167e03f3582bed90ed72)
+- [Dev Deps] update `tape`, `jscs`, `eslint`, `@ljharb/eslint-config` [`a3dd767`](https://github.com/ljharb/function-bind/commit/a3dd76720c795cb7f4586b0544efabf8aa107b8b)
+- Update `eslint` [`3dae2f7`](https://github.com/ljharb/function-bind/commit/3dae2f7423de30a2d20313ddb1edc19660142fe9)
+- Update `tape`, `covert`, `jscs` [`a181eee`](https://github.com/ljharb/function-bind/commit/a181eee0cfa24eb229c6e843a971f36e060a2f6a)
+- [Tests] up to `node` `v5.6`, `v4.3` [`964929a`](https://github.com/ljharb/function-bind/commit/964929a6a4ddb36fb128de2bcc20af5e4f22e1ed)
+- Test up to `io.js` `v2.1` [`2be7310`](https://github.com/ljharb/function-bind/commit/2be7310f2f74886a7124ca925be411117d41d5ea)
+- Update `tape`, `jscs`, `eslint`, `@ljharb/eslint-config` [`45f3d68`](https://github.com/ljharb/function-bind/commit/45f3d6865c6ca93726abcef54febe009087af101)
+- [Dev Deps] update `tape`, `jscs` [`6e1340d`](https://github.com/ljharb/function-bind/commit/6e1340d94642deaecad3e717825db641af4f8b1f)
+- [Tests] up to `io.js` `v3.3`, `node` `v4.1` [`d9bad2b`](https://github.com/ljharb/function-bind/commit/d9bad2b778b1b3a6dd2876087b88b3acf319f8cc)
+- Update `eslint` [`935590c`](https://github.com/ljharb/function-bind/commit/935590caa024ab356102e4858e8fc315b2ccc446)
+- [Dev Deps] update `jscs`, `eslint`, `@ljharb/eslint-config` [`8c9a1ef`](https://github.com/ljharb/function-bind/commit/8c9a1efd848e5167887aa8501857a0940a480c57)
+- Test on `io.js` `v2.2` [`9a3a38c`](https://github.com/ljharb/function-bind/commit/9a3a38c92013aed6e108666e7bd40969b84ac86e)
+- Run `travis-ci` tests on `iojs` and `node` v0.12; speed up builds; allow 0.8 failures. [`69afc26`](https://github.com/ljharb/function-bind/commit/69afc2617405b147dd2a8d8ae73ca9e9283f18b4)
+- [Dev Deps] Update `tape`, `eslint` [`36c1be0`](https://github.com/ljharb/function-bind/commit/36c1be0ab12b45fe5df6b0fdb01a5d5137fd0115)
+- Update `tape`, `jscs` [`98d8303`](https://github.com/ljharb/function-bind/commit/98d8303cd5ca1c6b8f985469f86b0d44d7d45f6e)
+- Update `jscs` [`9633a4e`](https://github.com/ljharb/function-bind/commit/9633a4e9fbf82051c240855166e468ba8ba0846f)
+- Update `tape`, `jscs` [`c80ef0f`](https://github.com/ljharb/function-bind/commit/c80ef0f46efc9791e76fa50de4414092ac147831)
+- Test up to `io.js` `v3.0` [`7e2c853`](https://github.com/ljharb/function-bind/commit/7e2c8537d52ab9cf5a655755561d8917684c0df4)
+- Test on `io.js` `v2.4` [`5a199a2`](https://github.com/ljharb/function-bind/commit/5a199a27ba46795ba5eaf0845d07d4b8232895c9)
+- Test on `io.js` `v2.3` [`a511b88`](https://github.com/ljharb/function-bind/commit/a511b8896de0bddf3b56862daa416c701f4d0453)
+- Fixing a typo from 822b4e1938db02dc9584aa434fd3a45cb20caf43 [`732d6b6`](https://github.com/ljharb/function-bind/commit/732d6b63a9b33b45230e630dbcac7a10855d3266)
+- Update `jscs` [`da52a48`](https://github.com/ljharb/function-bind/commit/da52a4886c06d6490f46ae30b15e4163ba08905d)
+- Lock covert to v1.0.0. [`d6150fd`](https://github.com/ljharb/function-bind/commit/d6150fda1e6f486718ebdeff823333d9e48e7430)
+
+## [v1.0.2](https://github.com/ljharb/function-bind/compare/v1.0.1...v1.0.2) - 2014-10-04
+
+## [v1.0.1](https://github.com/ljharb/function-bind/compare/v1.0.0...v1.0.1) - 2014-10-03
+
+### Merged
+
+- make CI build faster [`#3`](https://github.com/ljharb/function-bind/pull/3)
+
+### Commits
+
+- Using my standard jscs.json [`d8ee94c`](https://github.com/ljharb/function-bind/commit/d8ee94c993eff0a84cf5744fe6a29627f5cffa1a)
+- Adding `npm run lint` [`7571ab7`](https://github.com/ljharb/function-bind/commit/7571ab7dfdbd99b25a1dbb2d232622bd6f4f9c10)
+- Using consistent indentation [`e91a1b1`](https://github.com/ljharb/function-bind/commit/e91a1b13a61e99ec1e530e299b55508f74218a95)
+- Updating jscs [`7e17892`](https://github.com/ljharb/function-bind/commit/7e1789284bc629bc9c1547a61c9b227bbd8c7a65)
+- Using consistent quotes [`c50b57f`](https://github.com/ljharb/function-bind/commit/c50b57fcd1c5ec38320979c837006069ebe02b77)
+- Adding keywords [`cb94631`](https://github.com/ljharb/function-bind/commit/cb946314eed35f21186a25fb42fc118772f9ee00)
+- Directly export a function expression instead of using a declaration, and relying on hoisting. [`5a33c5f`](https://github.com/ljharb/function-bind/commit/5a33c5f45642de180e0d207110bf7d1843ceb87c)
+- Naming npm URL and badge in README; use SVG [`2aef8fc`](https://github.com/ljharb/function-bind/commit/2aef8fcb79d54e63a58ae557c4e60949e05d5e16)
+- Naming deps URLs in README [`04228d7`](https://github.com/ljharb/function-bind/commit/04228d766670ee45ca24e98345c1f6a7621065b5)
+- Naming travis-ci URLs in README; using SVG [`62c810c`](https://github.com/ljharb/function-bind/commit/62c810c2f54ced956cd4d4ab7b793055addfe36e)
+- Make sure functions are invoked correctly (also passing coverage tests) [`2b289b4`](https://github.com/ljharb/function-bind/commit/2b289b4dfbf037ffcfa4dc95eb540f6165e9e43a)
+- Removing the strict mode pragmas; they make tests fail. [`1aa701d`](https://github.com/ljharb/function-bind/commit/1aa701d199ddc3782476e8f7eef82679be97b845)
+- Adding myself as a contributor [`85fd57b`](https://github.com/ljharb/function-bind/commit/85fd57b0860e5a7af42de9a287f3f265fc6d72fc)
+- Adding strict mode pragmas [`915b08e`](https://github.com/ljharb/function-bind/commit/915b08e084c86a722eafe7245e21db74aa21ca4c)
+- Adding devDeps URLs to README [`4ccc731`](https://github.com/ljharb/function-bind/commit/4ccc73112c1769859e4ca3076caf4086b3cba2cd)
+- Fixing the description. [`a7a472c`](https://github.com/ljharb/function-bind/commit/a7a472cf649af515c635cf560fc478fbe48999c8)
+- Using a function expression instead of a function declaration. [`b5d3e4e`](https://github.com/ljharb/function-bind/commit/b5d3e4ea6aaffc63888953eeb1fbc7ff45f1fa14)
+- Updating tape [`f086be6`](https://github.com/ljharb/function-bind/commit/f086be6029fb56dde61a258c1340600fa174d1e0)
+- Updating jscs [`5f9bdb3`](https://github.com/ljharb/function-bind/commit/5f9bdb375ab13ba48f30852aab94029520c54d71)
+- Updating jscs [`9b409ba`](https://github.com/ljharb/function-bind/commit/9b409ba6118e23395a4e5d83ef39152aab9d3bfc)
+- Run coverage as part of tests. [`8e1b6d4`](https://github.com/ljharb/function-bind/commit/8e1b6d459f047d1bd4fee814e01247c984c80bd0)
+- Run linter as part of tests [`c1ca83f`](https://github.com/ljharb/function-bind/commit/c1ca83f832df94587d09e621beba682fabfaa987)
+- Updating covert [`701e837`](https://github.com/ljharb/function-bind/commit/701e83774b57b4d3ef631e1948143f43a72f4bb9)
+
+## [v1.0.0](https://github.com/ljharb/function-bind/compare/v0.2.0...v1.0.0) - 2014-08-09
+
+### Commits
+
+- Make sure old and unstable nodes don't fail Travis [`27adca3`](https://github.com/ljharb/function-bind/commit/27adca34a4ab6ad67b6dfde43942a1b103ce4d75)
+- Fixing an issue when the bound function is called as a constructor in ES3. [`e20122d`](https://github.com/ljharb/function-bind/commit/e20122d267d92ce553859b280cbbea5d27c07731)
+- Adding `npm run coverage` [`a2e29c4`](https://github.com/ljharb/function-bind/commit/a2e29c4ecaef9e2f6cd1603e868c139073375502)
+- Updating tape [`b741168`](https://github.com/ljharb/function-bind/commit/b741168b12b235b1717ff696087645526b69213c)
+- Upgrading tape [`63631a0`](https://github.com/ljharb/function-bind/commit/63631a04c7fbe97cc2fa61829cc27246d6986f74)
+- Updating tape [`363cb46`](https://github.com/ljharb/function-bind/commit/363cb46dafb23cb3e347729a22f9448051d78464)
+
+## v0.2.0 - 2014-03-23
+
+### Commits
+
+- Updating test coverage to match es5-shim. [`aa94d44`](https://github.com/ljharb/function-bind/commit/aa94d44b8f9d7f69f10e060db7709aa7a694e5d4)
+- initial [`942ee07`](https://github.com/ljharb/function-bind/commit/942ee07e94e542d91798137bc4b80b926137e066)
+- Setting the bound function's length properly. [`079f46a`](https://github.com/ljharb/function-bind/commit/079f46a2d3515b7c0b308c2c13fceb641f97ca25)
+- Ensuring that some older browsers will throw when given a regex. [`36ac55b`](https://github.com/ljharb/function-bind/commit/36ac55b87f460d4330253c92870aa26fbfe8227f)
+- Removing npm scripts that don't have dependencies [`9d2be60`](https://github.com/ljharb/function-bind/commit/9d2be600002cb8bc8606f8f3585ad3e05868c750)
+- Updating tape [`297a4ac`](https://github.com/ljharb/function-bind/commit/297a4acc5464db381940aafb194d1c88f4e678f3)
+- Skipping length tests for now. [`d9891ea`](https://github.com/ljharb/function-bind/commit/d9891ea4d2aaffa69f408339cdd61ff740f70565)
+- don't take my tea [`dccd930`](https://github.com/ljharb/function-bind/commit/dccd930bfd60ea10cb178d28c97550c3bc8c1e07)
diff --git a/server/node_modules/function-bind/LICENSE b/server/node_modules/function-bind/LICENSE
new file mode 100644
index 0000000..62d6d23
--- /dev/null
+++ b/server/node_modules/function-bind/LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2013 Raynos.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
diff --git a/server/node_modules/function-bind/README.md b/server/node_modules/function-bind/README.md
new file mode 100644
index 0000000..814c20b
--- /dev/null
+++ b/server/node_modules/function-bind/README.md
@@ -0,0 +1,46 @@
+# function-bind <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+
+[![dependency status][deps-svg]][deps-url]
+[![dev dependency status][dev-deps-svg]][dev-deps-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+Implementation of function.prototype.bind
+
+Old versions of phantomjs, Internet Explorer < 9, and node < 0.6 don't support `Function.prototype.bind`.
+
+## Example
+
+```js
+Function.prototype.bind = require("function-bind")
+```
+
+## Installation
+
+`npm install function-bind`
+
+## Contributors
+
+ - Raynos
+
+## MIT Licenced
+
+[package-url]: https://npmjs.org/package/function-bind
+[npm-version-svg]: https://versionbadg.es/Raynos/function-bind.svg
+[deps-svg]: https://david-dm.org/Raynos/function-bind.svg
+[deps-url]: https://david-dm.org/Raynos/function-bind
+[dev-deps-svg]: https://david-dm.org/Raynos/function-bind/dev-status.svg
+[dev-deps-url]: https://david-dm.org/Raynos/function-bind#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/function-bind.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/function-bind.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/function-bind.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=function-bind
+[codecov-image]: https://codecov.io/gh/Raynos/function-bind/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/Raynos/function-bind/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/Raynos/function-bind
+[actions-url]: https://github.com/Raynos/function-bind/actions
diff --git a/server/node_modules/function-bind/implementation.js b/server/node_modules/function-bind/implementation.js
new file mode 100644
index 0000000..fd4384c
--- /dev/null
+++ b/server/node_modules/function-bind/implementation.js
@@ -0,0 +1,84 @@
+'use strict';
+
+/* eslint no-invalid-this: 1 */
+
+var ERROR_MESSAGE = 'Function.prototype.bind called on incompatible ';
+var toStr = Object.prototype.toString;
+var max = Math.max;
+var funcType = '[object Function]';
+
+var concatty = function concatty(a, b) {
+    var arr = [];
+
+    for (var i = 0; i < a.length; i += 1) {
+        arr[i] = a[i];
+    }
+    for (var j = 0; j < b.length; j += 1) {
+        arr[j + a.length] = b[j];
+    }
+
+    return arr;
+};
+
+var slicy = function slicy(arrLike, offset) {
+    var arr = [];
+    for (var i = offset || 0, j = 0; i < arrLike.length; i += 1, j += 1) {
+        arr[j] = arrLike[i];
+    }
+    return arr;
+};
+
+var joiny = function (arr, joiner) {
+    var str = '';
+    for (var i = 0; i < arr.length; i += 1) {
+        str += arr[i];
+        if (i + 1 < arr.length) {
+            str += joiner;
+        }
+    }
+    return str;
+};
+
+module.exports = function bind(that) {
+    var target = this;
+    if (typeof target !== 'function' || toStr.apply(target) !== funcType) {
+        throw new TypeError(ERROR_MESSAGE + target);
+    }
+    var args = slicy(arguments, 1);
+
+    var bound;
+    var binder = function () {
+        if (this instanceof bound) {
+            var result = target.apply(
+                this,
+                concatty(args, arguments)
+            );
+            if (Object(result) === result) {
+                return result;
+            }
+            return this;
+        }
+        return target.apply(
+            that,
+            concatty(args, arguments)
+        );
+
+    };
+
+    var boundLength = max(0, target.length - args.length);
+    var boundArgs = [];
+    for (var i = 0; i < boundLength; i++) {
+        boundArgs[i] = '$' + i;
+    }
+
+    bound = Function('binder', 'return function (' + joiny(boundArgs, ',') + '){ return binder.apply(this,arguments); }')(binder);
+
+    if (target.prototype) {
+        var Empty = function Empty() {};
+        Empty.prototype = target.prototype;
+        bound.prototype = new Empty();
+        Empty.prototype = null;
+    }
+
+    return bound;
+};
diff --git a/server/node_modules/function-bind/index.js b/server/node_modules/function-bind/index.js
new file mode 100644
index 0000000..3bb6b96
--- /dev/null
+++ b/server/node_modules/function-bind/index.js
@@ -0,0 +1,5 @@
+'use strict';
+
+var implementation = require('./implementation');
+
+module.exports = Function.prototype.bind || implementation;
diff --git a/server/node_modules/function-bind/package.json b/server/node_modules/function-bind/package.json
new file mode 100644
index 0000000..6185963
--- /dev/null
+++ b/server/node_modules/function-bind/package.json
@@ -0,0 +1,87 @@
+{
+  "name": "function-bind",
+  "version": "1.1.2",
+  "description": "Implementation of Function.prototype.bind",
+  "keywords": [
+    "function",
+    "bind",
+    "shim",
+    "es5"
+  ],
+  "author": "Raynos <raynos2@gmail.com>",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/Raynos/function-bind.git"
+  },
+  "funding": {
+    "url": "https://github.com/sponsors/ljharb"
+  },
+  "main": "index",
+  "homepage": "https://github.com/Raynos/function-bind",
+  "contributors": [
+    {
+      "name": "Raynos"
+    },
+    {
+      "name": "Jordan Harband",
+      "url": "https://github.com/ljharb"
+    }
+  ],
+  "bugs": {
+    "url": "https://github.com/Raynos/function-bind/issues",
+    "email": "raynos2@gmail.com"
+  },
+  "devDependencies": {
+    "@ljharb/eslint-config": "^21.1.0",
+    "aud": "^2.0.3",
+    "auto-changelog": "^2.4.0",
+    "eslint": "=8.8.0",
+    "in-publish": "^2.0.1",
+    "npmignore": "^0.3.0",
+    "nyc": "^10.3.2",
+    "safe-publish-latest": "^2.0.0",
+    "tape": "^5.7.1"
+  },
+  "license": "MIT",
+  "scripts": {
+    "prepublishOnly": "safe-publish-latest",
+    "prepublish": "not-in-publish || npm run prepublishOnly",
+    "prepack": "npmignore --auto --commentLines=autogenerated",
+    "pretest": "npm run lint",
+    "test": "npm run tests-only",
+    "posttest": "aud --production",
+    "tests-only": "nyc tape 'test/**/*.js'",
+    "lint": "eslint --ext=js,mjs .",
+    "version": "auto-changelog && git add CHANGELOG.md",
+    "postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+  },
+  "testling": {
+    "files": "test/index.js",
+    "browsers": [
+      "ie/8..latest",
+      "firefox/16..latest",
+      "firefox/nightly",
+      "chrome/22..latest",
+      "chrome/canary",
+      "opera/12..latest",
+      "opera/next",
+      "safari/5.1..latest",
+      "ipad/6.0..latest",
+      "iphone/6.0..latest",
+      "android-browser/4.2..latest"
+    ]
+  },
+  "auto-changelog": {
+    "output": "CHANGELOG.md",
+    "template": "keepachangelog",
+    "unreleased": false,
+    "commitLimit": false,
+    "backfillLimit": false,
+    "hideCredit": true
+  },
+  "publishConfig": {
+    "ignore": [
+      ".github/workflows"
+    ]
+  }
+}
diff --git a/server/node_modules/function-bind/test/.eslintrc b/server/node_modules/function-bind/test/.eslintrc
new file mode 100644
index 0000000..8a56d5b
--- /dev/null
+++ b/server/node_modules/function-bind/test/.eslintrc
@@ -0,0 +1,9 @@
+{
+	"rules": {
+		"array-bracket-newline": 0,
+		"array-element-newline": 0,
+		"max-statements-per-line": [2, { "max": 2 }],
+		"no-invalid-this": 0,
+		"no-magic-numbers": 0,
+	}
+}
diff --git a/server/node_modules/function-bind/test/index.js b/server/node_modules/function-bind/test/index.js
new file mode 100644
index 0000000..2edecce
--- /dev/null
+++ b/server/node_modules/function-bind/test/index.js
@@ -0,0 +1,252 @@
+// jscs:disable requireUseStrict
+
+var test = require('tape');
+
+var functionBind = require('../implementation');
+var getCurrentContext = function () { return this; };
+
+test('functionBind is a function', function (t) {
+    t.equal(typeof functionBind, 'function');
+    t.end();
+});
+
+test('non-functions', function (t) {
+    var nonFunctions = [true, false, [], {}, 42, 'foo', NaN, /a/g];
+    t.plan(nonFunctions.length);
+    for (var i = 0; i < nonFunctions.length; ++i) {
+        try { functionBind.call(nonFunctions[i]); } catch (ex) {
+            t.ok(ex instanceof TypeError, 'throws when given ' + String(nonFunctions[i]));
+        }
+    }
+    t.end();
+});
+
+test('without a context', function (t) {
+    t.test('binds properly', function (st) {
+        var args, context;
+        var namespace = {
+            func: functionBind.call(function () {
+                args = Array.prototype.slice.call(arguments);
+                context = this;
+            })
+        };
+        namespace.func(1, 2, 3);
+        st.deepEqual(args, [1, 2, 3]);
+        st.equal(context, getCurrentContext.call());
+        st.end();
+    });
+
+    t.test('binds properly, and still supplies bound arguments', function (st) {
+        var args, context;
+        var namespace = {
+            func: functionBind.call(function () {
+                args = Array.prototype.slice.call(arguments);
+                context = this;
+            }, undefined, 1, 2, 3)
+        };
+        namespace.func(4, 5, 6);
+        st.deepEqual(args, [1, 2, 3, 4, 5, 6]);
+        st.equal(context, getCurrentContext.call());
+        st.end();
+    });
+
+    t.test('returns properly', function (st) {
+        var args;
+        var namespace = {
+            func: functionBind.call(function () {
+                args = Array.prototype.slice.call(arguments);
+                return this;
+            }, null)
+        };
+        var context = namespace.func(1, 2, 3);
+        st.equal(context, getCurrentContext.call(), 'returned context is namespaced context');
+        st.deepEqual(args, [1, 2, 3], 'passed arguments are correct');
+        st.end();
+    });
+
+    t.test('returns properly with bound arguments', function (st) {
+        var args;
+        var namespace = {
+            func: functionBind.call(function () {
+                args = Array.prototype.slice.call(arguments);
+                return this;
+            }, null, 1, 2, 3)
+        };
+        var context = namespace.func(4, 5, 6);
+        st.equal(context, getCurrentContext.call(), 'returned context is namespaced context');
+        st.deepEqual(args, [1, 2, 3, 4, 5, 6], 'passed arguments are correct');
+        st.end();
+    });
+
+    t.test('called as a constructor', function (st) {
+        var thunkify = function (value) {
+            return function () { return value; };
+        };
+        st.test('returns object value', function (sst) {
+            var expectedReturnValue = [1, 2, 3];
+            var Constructor = functionBind.call(thunkify(expectedReturnValue), null);
+            var result = new Constructor();
+            sst.equal(result, expectedReturnValue);
+            sst.end();
+        });
+
+        st.test('does not return primitive value', function (sst) {
+            var Constructor = functionBind.call(thunkify(42), null);
+            var result = new Constructor();
+            sst.notEqual(result, 42);
+            sst.end();
+        });
+
+        st.test('object from bound constructor is instance of original and bound constructor', function (sst) {
+            var A = function (x) {
+                this.name = x || 'A';
+            };
+            var B = functionBind.call(A, null, 'B');
+
+            var result = new B();
+            sst.ok(result instanceof B, 'result is instance of bound constructor');
+            sst.ok(result instanceof A, 'result is instance of original constructor');
+            sst.end();
+        });
+
+        st.end();
+    });
+
+    t.end();
+});
+
+test('with a context', function (t) {
+    t.test('with no bound arguments', function (st) {
+        var args, context;
+        var boundContext = {};
+        var namespace = {
+            func: functionBind.call(function () {
+                args = Array.prototype.slice.call(arguments);
+                context = this;
+            }, boundContext)
+        };
+        namespace.func(1, 2, 3);
+        st.equal(context, boundContext, 'binds a context properly');
+        st.deepEqual(args, [1, 2, 3], 'supplies passed arguments');
+        st.end();
+    });
+
+    t.test('with bound arguments', function (st) {
+        var args, context;
+        var boundContext = {};
+        var namespace = {
+            func: functionBind.call(function () {
+                args = Array.prototype.slice.call(arguments);
+                context = this;
+            }, boundContext, 1, 2, 3)
+        };
+        namespace.func(4, 5, 6);
+        st.equal(context, boundContext, 'binds a context properly');
+        st.deepEqual(args, [1, 2, 3, 4, 5, 6], 'supplies bound and passed arguments');
+        st.end();
+    });
+
+    t.test('returns properly', function (st) {
+        var boundContext = {};
+        var args;
+        var namespace = {
+            func: functionBind.call(function () {
+                args = Array.prototype.slice.call(arguments);
+                return this;
+            }, boundContext)
+        };
+        var context = namespace.func(1, 2, 3);
+        st.equal(context, boundContext, 'returned context is bound context');
+        st.notEqual(context, getCurrentContext.call(), 'returned context is not lexical context');
+        st.deepEqual(args, [1, 2, 3], 'passed arguments are correct');
+        st.end();
+    });
+
+    t.test('returns properly with bound arguments', function (st) {
+        var boundContext = {};
+        var args;
+        var namespace = {
+            func: functionBind.call(function () {
+                args = Array.prototype.slice.call(arguments);
+                return this;
+            }, boundContext, 1, 2, 3)
+        };
+        var context = namespace.func(4, 5, 6);
+        st.equal(context, boundContext, 'returned context is bound context');
+        st.notEqual(context, getCurrentContext.call(), 'returned context is not lexical context');
+        st.deepEqual(args, [1, 2, 3, 4, 5, 6], 'passed arguments are correct');
+        st.end();
+    });
+
+    t.test('passes the correct arguments when called as a constructor', function (st) {
+        var expected = { name: 'Correct' };
+        var namespace = {
+            Func: functionBind.call(function (arg) {
+                return arg;
+            }, { name: 'Incorrect' })
+        };
+        var returned = new namespace.Func(expected);
+        st.equal(returned, expected, 'returns the right arg when called as a constructor');
+        st.end();
+    });
+
+    t.test('has the new instance\'s context when called as a constructor', function (st) {
+        var actualContext;
+        var expectedContext = { foo: 'bar' };
+        var namespace = {
+            Func: functionBind.call(function () {
+                actualContext = this;
+            }, expectedContext)
+        };
+        var result = new namespace.Func();
+        st.equal(result instanceof namespace.Func, true);
+        st.notEqual(actualContext, expectedContext);
+        st.end();
+    });
+
+    t.end();
+});
+
+test('bound function length', function (t) {
+    t.test('sets a correct length without thisArg', function (st) {
+        var subject = functionBind.call(function (a, b, c) { return a + b + c; });
+        st.equal(subject.length, 3);
+        st.equal(subject(1, 2, 3), 6);
+        st.end();
+    });
+
+    t.test('sets a correct length with thisArg', function (st) {
+        var subject = functionBind.call(function (a, b, c) { return a + b + c; }, {});
+        st.equal(subject.length, 3);
+        st.equal(subject(1, 2, 3), 6);
+        st.end();
+    });
+
+    t.test('sets a correct length without thisArg and first argument', function (st) {
+        var subject = functionBind.call(function (a, b, c) { return a + b + c; }, undefined, 1);
+        st.equal(subject.length, 2);
+        st.equal(subject(2, 3), 6);
+        st.end();
+    });
+
+    t.test('sets a correct length with thisArg and first argument', function (st) {
+        var subject = functionBind.call(function (a, b, c) { return a + b + c; }, {}, 1);
+        st.equal(subject.length, 2);
+        st.equal(subject(2, 3), 6);
+        st.end();
+    });
+
+    t.test('sets a correct length without thisArg and too many arguments', function (st) {
+        var subject = functionBind.call(function (a, b, c) { return a + b + c; }, undefined, 1, 2, 3, 4);
+        st.equal(subject.length, 0);
+        st.equal(subject(), 6);
+        st.end();
+    });
+
+    t.test('sets a correct length with thisArg and too many arguments', function (st) {
+        var subject = functionBind.call(function (a, b, c) { return a + b + c; }, {}, 1, 2, 3, 4);
+        st.equal(subject.length, 0);
+        st.equal(subject(), 6);
+        st.end();
+    });
+});
diff --git a/server/node_modules/gauge/LICENSE.md b/server/node_modules/gauge/LICENSE.md
new file mode 100644
index 0000000..5fc208f
--- /dev/null
+++ b/server/node_modules/gauge/LICENSE.md
@@ -0,0 +1,20 @@
+
+
+ISC License
+
+Copyright npm, Inc.
+
+Permission to use, copy, modify, and/or distribute this
+software for any purpose with or without fee is hereby
+granted, provided that the above copyright notice and this
+permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND NPM DISCLAIMS ALL
+WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+EVENT SHALL NPM BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/gauge/README.md b/server/node_modules/gauge/README.md
new file mode 100644
index 0000000..cbef5a5
--- /dev/null
+++ b/server/node_modules/gauge/README.md
@@ -0,0 +1,402 @@
+gauge
+=====
+
+A nearly stateless terminal based horizontal gauge / progress bar.
+
+```javascript
+var Gauge = require("gauge")
+
+var gauge = new Gauge()
+
+gauge.show("working…", 0)
+setTimeout(() => { gauge.pulse(); gauge.show("working…", 0.25) }, 500)
+setTimeout(() => { gauge.pulse(); gauge.show("working…", 0.50) }, 1000)
+setTimeout(() => { gauge.pulse(); gauge.show("working…", 0.75) }, 1500)
+setTimeout(() => { gauge.pulse(); gauge.show("working…", 0.99) }, 2000)
+setTimeout(() => gauge.hide(), 2300)
+```
+
+See also the [demos](docs/demo.js):
+
+![](./docs/gauge-demo.gif)
+
+
+### CHANGES FROM 1.x
+
+Gauge 2.x is breaking release, please see the [changelog] for details on
+what's changed if you were previously a user of this module.
+
+[changelog]: CHANGELOG.md
+
+### THE GAUGE CLASS
+
+This is the typical interface to the module– it provides a pretty
+fire-and-forget interface to displaying your status information.
+
+```
+var Gauge = require("gauge")
+
+var gauge = new Gauge([stream], [options])
+```
+
+* **stream** – *(optional, default STDERR)* A stream that progress bar
+  updates are to be written to.  Gauge honors backpressure and will pause
+  most writing if it is indicated.
+* **options** – *(optional)* An option object.
+
+Constructs a new gauge. Gauges are drawn on a single line, and are not drawn
+if **stream** isn't a tty and a tty isn't explicitly provided.
+
+If **stream** is a terminal or if you pass in **tty** to **options** then we
+will detect terminal resizes and redraw to fit.  We do this by watching for
+`resize` events on the tty.  (To work around a bug in versions of Node prior
+to 2.5.0, we watch for them on stdout if the tty is stderr.) Resizes to
+larger window sizes will be clean, but shrinking the window will always
+result in some cruft.
+
+**IMPORTANT:** If you previously were passing in a non-tty stream but you still
+want output (for example, a stream wrapped by the `ansi` module) then you
+need to pass in the **tty** option below, as `gauge` needs access to
+the underlying tty in order to do things like terminal resizes and terminal
+width detection.
+
+The **options** object can have the following properties, all of which are
+optional:
+
+* **updateInterval**: How often gauge updates should be drawn, in milliseconds.
+* **fixedFramerate**: Defaults to false on node 0.8, true on everything
+  else.  When this is true a timer is created to trigger once every
+  `updateInterval` ms, when false, updates are printed as soon as they come
+  in but updates more often than `updateInterval` are ignored.  The reason
+  0.8 doesn't have this set to true is that it can't `unref` its timer and
+  so it would stop your program from exiting– if you want to use this
+  feature with 0.8 just make sure you call `gauge.disable()` before you
+  expect your program to exit.
+* **themes**: A themeset to use when selecting the theme to use. Defaults
+  to `gauge/themes`, see the [themes] documentation for details.
+* **theme**: Select a theme for use, it can be a:
+  * Theme object, in which case the **themes** is not used.
+  * The name of a theme, which will be looked up in the current *themes*
+    object.
+  * A configuration object with any of `hasUnicode`, `hasColor` or
+    `platform` keys, which if will be used to override our guesses when making
+    a default theme selection.
+
+  If no theme is selected then a default is picked using a combination of our
+  best guesses at your OS, color support and unicode support.
+* **template**: Describes what you want your gauge to look like.  The
+  default is what npm uses.  Detailed [documentation] is later in this
+  document.
+* **hideCursor**: Defaults to true.  If true, then the cursor will be hidden
+  while the gauge is displayed.
+* **tty**: The tty that you're ultimately writing to.  Defaults to the same
+  as **stream**.  This is used for detecting the width of the terminal and
+  resizes. The width used is `tty.columns - 1`. If no tty is available then
+  a width of `79` is assumed.
+* **enabled**: Defaults to true if `tty` is a TTY, false otherwise.  If true
+  the gauge starts enabled.  If disabled then all update commands are
+  ignored and no gauge will be printed until you call `.enable()`.
+* **Plumbing**: The class to use to actually generate the gauge for
+  printing.  This defaults to `require('gauge/plumbing')` and ordinarily you
+  shouldn't need to override this.
+* **cleanupOnExit**: Defaults to true. Ordinarily we register an exit
+  handler to make sure your cursor is turned back on and the progress bar
+  erased when your process exits, even if you Ctrl-C out or otherwise exit
+  unexpectedly. You can disable this and it won't register the exit handler.
+
+[has-unicode]: https://www.npmjs.com/package/has-unicode
+[themes]: #themes
+[documentation]: #templates
+
+#### `gauge.show(section | status, [completed])`
+
+The first argument is either the section, the name of the current thing
+contributing to progress, or an object with keys like **section**,
+**subsection** & **completed** (or any others you have types for in a custom
+template).  If you don't want to update or set any of these you can pass
+`null` and it will be ignored.
+
+The second argument is the percent completed as a value between 0 and 1.
+Without it, completion is just not updated. You'll also note that completion
+can be passed in as part of a status object as the first argument. If both
+it and the completed argument are passed in, the completed argument wins.
+
+#### `gauge.hide([cb])`
+
+Removes the gauge from the terminal.  Optionally, callback `cb` after IO has
+had an opportunity to happen (currently this just means after `setImmediate`
+has called back.)
+
+It turns out this is important when you're pausing the progress bar on one
+filehandle and printing to another– otherwise (with a big enough print) node
+can end up printing the "end progress bar" bits to the progress bar filehandle
+while other stuff is printing to another filehandle. These getting interleaved
+can cause corruption in some terminals.
+
+#### `gauge.pulse([subsection])`
+
+* **subsection** – *(optional)* The specific thing that triggered this pulse
+
+Spins the spinner in the gauge to show output.  If **subsection** is
+included then it will be combined with the last name passed to `gauge.show`.
+
+#### `gauge.disable()`
+
+Hides the gauge and ignores further calls to `show` or `pulse`.
+
+#### `gauge.enable()`
+
+Shows the gauge and resumes updating when `show` or `pulse` is called.
+
+#### `gauge.isEnabled()`
+
+Returns true if the gauge is enabled.
+
+#### `gauge.setThemeset(themes)`
+
+Change the themeset to select a theme from. The same as the `themes` option
+used in the constructor. The theme will be reselected from this themeset.
+
+#### `gauge.setTheme(theme)`
+
+Change the active theme, will be displayed with the next show or pulse. This can be:
+
+* Theme object, in which case the **themes** is not used.
+* The name of a theme, which will be looked up in the current *themes*
+  object.
+* A configuration object with any of `hasUnicode`, `hasColor` or
+  `platform` keys, which if will be used to override our guesses when making
+  a default theme selection.
+
+If no theme is selected then a default is picked using a combination of our
+best guesses at your OS, color support and unicode support.
+
+#### `gauge.setTemplate(template)`
+
+Change the active template, will be displayed with the next show or pulse
+
+### Tracking Completion
+
+If you have more than one thing going on that you want to track completion
+of, you may find the related [are-we-there-yet] helpful.  It's `change`
+event can be wired up to the `show` method to get a more traditional
+progress bar interface.
+
+[are-we-there-yet]: https://www.npmjs.com/package/are-we-there-yet
+
+### THEMES
+
+```
+var themes = require('gauge/themes')
+
+// fetch the default color unicode theme for this platform
+var ourTheme = themes({hasUnicode: true, hasColor: true})
+
+// fetch the default non-color unicode theme for osx
+var ourTheme = themes({hasUnicode: true, hasColor: false, platform: 'darwin'})
+
+// create a new theme based on the color ascii theme for this platform
+// that brackets the progress bar with arrows
+var ourTheme = themes.newTheme(themes({hasUnicode: false, hasColor: true}), {
+  preProgressbar: '→',
+  postProgressbar: '←'
+})
+```
+
+The object returned by `gauge/themes` is an instance of the `ThemeSet` class.
+
+```
+var ThemeSet = require('gauge/theme-set')
+var themes = new ThemeSet()
+// or
+var themes = require('gauge/themes')
+var mythemes = themes.newThemeSet() // creates a new themeset based on the default themes
+```
+
+#### themes(opts)
+#### themes.getDefault(opts)
+
+Theme objects are a function that fetches the default theme based on
+platform, unicode and color support.
+
+Options is an object with the following properties:
+
+* **hasUnicode** - If true, fetch a unicode theme, if no unicode theme is
+  available then a non-unicode theme will be used.
+* **hasColor** - If true, fetch a color theme, if no color theme is
+  available a non-color theme will be used.
+* **platform** (optional) - Defaults to `process.platform`.  If no
+  platform match is available then `fallback` is used instead.
+
+If no compatible theme can be found then an error will be thrown with a
+`code` of `EMISSINGTHEME`.
+
+#### themes.addTheme(themeName, themeObj)
+#### themes.addTheme(themeName, [parentTheme], newTheme)
+
+Adds a named theme to the themeset.  You can pass in either a theme object,
+as returned by `themes.newTheme` or the arguments you'd pass to
+`themes.newTheme`.
+
+#### themes.getThemeNames()
+
+Return a list of all of the names of the themes in this themeset. Suitable
+for use in `themes.getTheme(…)`.
+
+#### themes.getTheme(name)
+
+Returns the theme object from this theme set named `name`.
+
+If `name` does not exist in this themeset an error will be thrown with
+a `code` of `EMISSINGTHEME`.
+
+#### themes.setDefault([opts], themeName)
+
+`opts` is an object with the following properties.
+
+* **platform** - Defaults to `'fallback'`.  If your theme is platform
+  specific, specify that here with the platform from `process.platform`, eg,
+  `win32`, `darwin`, etc.
+* **hasUnicode** - Defaults to `false`. If your theme uses unicode you
+  should set this to true.
+* **hasColor** - Defaults to `false`.  If your theme uses color you should
+  set this to true.
+
+`themeName` is the name of the theme (as given to `addTheme`) to use for
+this set of `opts`.
+
+#### themes.newTheme([parentTheme,] newTheme)
+
+Create a new theme object based on `parentTheme`.  If no `parentTheme` is
+provided then a minimal parentTheme that defines functions for rendering the
+activity indicator (spinner) and progress bar will be defined. (This
+fallback parent is defined in `gauge/base-theme`.)
+
+newTheme should be a bare object– we'll start by discussing the properties
+defined by the default themes:
+
+* **preProgressbar** - displayed prior to the progress bar, if the progress
+  bar is displayed.
+* **postProgressbar** - displayed after the progress bar, if the progress bar
+  is displayed.
+* **progressBarTheme** - The subtheme passed through to the progress bar
+  renderer, it's an object with `complete` and `remaining` properties
+  that are the strings you want repeated for those sections of the progress
+  bar.
+* **activityIndicatorTheme** - The theme for the activity indicator (spinner),
+  this can either be a string, in which each character is a different step, or
+  an array of strings.
+* **preSubsection** - Displayed as a separator between the `section` and
+  `subsection` when the latter is printed.
+
+More generally, themes can have any value that would be a valid value when rendering
+templates. The properties in the theme are used when their name matches a type in
+the template. Their values can be:
+
+* **strings & numbers** - They'll be included as is
+* **function (values, theme, width)** - Should return what you want in your output.
+  *values* is an object with values provided via `gauge.show`,
+  *theme* is the theme specific to this item (see below) or this theme object,
+  and *width* is the number of characters wide your result should be.
+
+There are a couple of special prefixes:
+
+* **pre** - Is shown prior to the property, if its displayed.
+* **post** - Is shown after the property, if its displayed.
+
+And one special suffix:
+
+* **Theme** - Its value is passed to a function-type item as the theme.
+
+#### themes.addToAllThemes(theme)
+
+This *mixes-in* `theme` into all themes currently defined. It also adds it
+to the default parent theme for this themeset, so future themes added to
+this themeset will get the values from `theme` by default.
+
+#### themes.newThemeSet()
+
+Copy the current themeset into a new one.  This allows you to easily inherit
+one themeset from another.
+
+### TEMPLATES
+
+A template is an array of objects and strings that, after being evaluated,
+will be turned into the gauge line.  The default template is:
+
+```javascript
+[
+    {type: 'progressbar', length: 20},
+    {type: 'activityIndicator', kerning: 1, length: 1},
+    {type: 'section', kerning: 1, default: ''},
+    {type: 'subsection', kerning: 1, default: ''}
+]
+```
+
+The various template elements can either be **plain strings**, in which case they will
+be be included verbatum in the output, or objects with the following properties:
+
+* *type* can be any of the following plus any keys you pass into `gauge.show` plus
+  any keys you have on a custom theme.
+  * `section` – What big thing you're working on now.
+  * `subsection` – What component of that thing is currently working.
+  * `activityIndicator` – Shows a spinner using the `activityIndicatorTheme`
+    from your active theme.
+  * `progressbar` – A progress bar representing your current `completed`
+    using the `progressbarTheme` from your active theme.
+* *kerning* – Number of spaces that must be between this item and other
+  items, if this item is displayed at all.
+* *maxLength* – The maximum length for this element. If its value is longer it
+  will be truncated.
+* *minLength* – The minimum length for this element. If its value is shorter it
+  will be padded according to the *align* value.
+* *align* – (Default: left) Possible values "left", "right" and "center". Works
+  as you'd expect from word processors.
+* *length* – Provides a single value for both *minLength* and *maxLength*. If both
+  *length* and *minLength or *maxLength* are specified then the latter take precedence.
+* *value* – A literal value to use for this template item.
+* *default* – A default value to use for this template item if a value
+  wasn't otherwise passed in.
+
+### PLUMBING
+
+This is the super simple, assume nothing, do no magic internals used by gauge to
+implement its ordinary interface.
+
+```
+var Plumbing = require('gauge/plumbing')
+var gauge = new Plumbing(theme, template, width)
+```
+
+* **theme**: The theme to use.
+* **template**: The template to use.
+* **width**: How wide your gauge should be
+
+#### `gauge.setTheme(theme)`
+
+Change the active theme.
+
+#### `gauge.setTemplate(template)`
+
+Change the active template.
+
+#### `gauge.setWidth(width)`
+
+Change the width to render at.
+
+#### `gauge.hide()`
+
+Return the string necessary to hide the progress bar
+
+#### `gauge.hideCursor()`
+
+Return a string to hide the cursor.
+
+#### `gauge.showCursor()`
+
+Return a string to show the cursor.
+
+#### `gauge.show(status)`
+
+Using `status` for values, render the provided template with the theme and return
+a string that is suitable for printing to update the gauge.
diff --git a/server/node_modules/gauge/lib/base-theme.js b/server/node_modules/gauge/lib/base-theme.js
new file mode 100644
index 0000000..00bf568
--- /dev/null
+++ b/server/node_modules/gauge/lib/base-theme.js
@@ -0,0 +1,18 @@
+'use strict'
+var spin = require('./spin.js')
+var progressBar = require('./progress-bar.js')
+
+module.exports = {
+  activityIndicator: function (values, theme, width) {
+    if (values.spun == null) {
+      return
+    }
+    return spin(theme, values.spun)
+  },
+  progressbar: function (values, theme, width) {
+    if (values.completed == null) {
+      return
+    }
+    return progressBar(theme, width, values.completed)
+  },
+}
diff --git a/server/node_modules/gauge/lib/error.js b/server/node_modules/gauge/lib/error.js
new file mode 100644
index 0000000..d9914ba
--- /dev/null
+++ b/server/node_modules/gauge/lib/error.js
@@ -0,0 +1,24 @@
+'use strict'
+var util = require('util')
+
+var User = exports.User = function User (msg) {
+  var err = new Error(msg)
+  Error.captureStackTrace(err, User)
+  err.code = 'EGAUGE'
+  return err
+}
+
+exports.MissingTemplateValue = function MissingTemplateValue (item, values) {
+  var err = new User(util.format('Missing template value "%s"', item.type))
+  Error.captureStackTrace(err, MissingTemplateValue)
+  err.template = item
+  err.values = values
+  return err
+}
+
+exports.Internal = function Internal (msg) {
+  var err = new Error(msg)
+  Error.captureStackTrace(err, Internal)
+  err.code = 'EGAUGEINTERNAL'
+  return err
+}
diff --git a/server/node_modules/gauge/lib/has-color.js b/server/node_modules/gauge/lib/has-color.js
new file mode 100644
index 0000000..16cba0e
--- /dev/null
+++ b/server/node_modules/gauge/lib/has-color.js
@@ -0,0 +1,4 @@
+'use strict'
+var colorSupport = require('color-support')
+
+module.exports = colorSupport().hasBasic
diff --git a/server/node_modules/gauge/lib/index.js b/server/node_modules/gauge/lib/index.js
new file mode 100644
index 0000000..37fc5ac
--- /dev/null
+++ b/server/node_modules/gauge/lib/index.js
@@ -0,0 +1,289 @@
+'use strict'
+var Plumbing = require('./plumbing.js')
+var hasUnicode = require('has-unicode')
+var hasColor = require('./has-color.js')
+var onExit = require('signal-exit')
+var defaultThemes = require('./themes')
+var setInterval = require('./set-interval.js')
+var process = require('./process.js')
+var setImmediate = require('./set-immediate')
+
+module.exports = Gauge
+
+function callWith (obj, method) {
+  return function () {
+    return method.call(obj)
+  }
+}
+
+function Gauge (arg1, arg2) {
+  var options, writeTo
+  if (arg1 && arg1.write) {
+    writeTo = arg1
+    options = arg2 || {}
+  } else if (arg2 && arg2.write) {
+    writeTo = arg2
+    options = arg1 || {}
+  } else {
+    writeTo = process.stderr
+    options = arg1 || arg2 || {}
+  }
+
+  this._status = {
+    spun: 0,
+    section: '',
+    subsection: '',
+  }
+  this._paused = false // are we paused for back pressure?
+  this._disabled = true // are all progress bar updates disabled?
+  this._showing = false // do we WANT the progress bar on screen
+  this._onScreen = false // IS the progress bar on screen
+  this._needsRedraw = false // should we print something at next tick?
+  this._hideCursor = options.hideCursor == null ? true : options.hideCursor
+  this._fixedFramerate = options.fixedFramerate == null
+    ? !(/^v0\.8\./.test(process.version))
+    : options.fixedFramerate
+  this._lastUpdateAt = null
+  this._updateInterval = options.updateInterval == null ? 50 : options.updateInterval
+
+  this._themes = options.themes || defaultThemes
+  this._theme = options.theme
+  var theme = this._computeTheme(options.theme)
+  var template = options.template || [
+    { type: 'progressbar', length: 20 },
+    { type: 'activityIndicator', kerning: 1, length: 1 },
+    { type: 'section', kerning: 1, default: '' },
+    { type: 'subsection', kerning: 1, default: '' },
+  ]
+  this.setWriteTo(writeTo, options.tty)
+  var PlumbingClass = options.Plumbing || Plumbing
+  this._gauge = new PlumbingClass(theme, template, this.getWidth())
+
+  this._$$doRedraw = callWith(this, this._doRedraw)
+  this._$$handleSizeChange = callWith(this, this._handleSizeChange)
+
+  this._cleanupOnExit = options.cleanupOnExit == null || options.cleanupOnExit
+  this._removeOnExit = null
+
+  if (options.enabled || (options.enabled == null && this._tty && this._tty.isTTY)) {
+    this.enable()
+  } else {
+    this.disable()
+  }
+}
+Gauge.prototype = {}
+
+Gauge.prototype.isEnabled = function () {
+  return !this._disabled
+}
+
+Gauge.prototype.setTemplate = function (template) {
+  this._gauge.setTemplate(template)
+  if (this._showing) {
+    this._requestRedraw()
+  }
+}
+
+Gauge.prototype._computeTheme = function (theme) {
+  if (!theme) {
+    theme = {}
+  }
+  if (typeof theme === 'string') {
+    theme = this._themes.getTheme(theme)
+  } else if (
+    Object.keys(theme).length === 0 || theme.hasUnicode != null || theme.hasColor != null
+  ) {
+    var useUnicode = theme.hasUnicode == null ? hasUnicode() : theme.hasUnicode
+    var useColor = theme.hasColor == null ? hasColor : theme.hasColor
+    theme = this._themes.getDefault({
+      hasUnicode: useUnicode,
+      hasColor: useColor,
+      platform: theme.platform,
+    })
+  }
+  return theme
+}
+
+Gauge.prototype.setThemeset = function (themes) {
+  this._themes = themes
+  this.setTheme(this._theme)
+}
+
+Gauge.prototype.setTheme = function (theme) {
+  this._gauge.setTheme(this._computeTheme(theme))
+  if (this._showing) {
+    this._requestRedraw()
+  }
+  this._theme = theme
+}
+
+Gauge.prototype._requestRedraw = function () {
+  this._needsRedraw = true
+  if (!this._fixedFramerate) {
+    this._doRedraw()
+  }
+}
+
+Gauge.prototype.getWidth = function () {
+  return ((this._tty && this._tty.columns) || 80) - 1
+}
+
+Gauge.prototype.setWriteTo = function (writeTo, tty) {
+  var enabled = !this._disabled
+  if (enabled) {
+    this.disable()
+  }
+  this._writeTo = writeTo
+  this._tty = tty ||
+    (writeTo === process.stderr && process.stdout.isTTY && process.stdout) ||
+    (writeTo.isTTY && writeTo) ||
+    this._tty
+  if (this._gauge) {
+    this._gauge.setWidth(this.getWidth())
+  }
+  if (enabled) {
+    this.enable()
+  }
+}
+
+Gauge.prototype.enable = function () {
+  if (!this._disabled) {
+    return
+  }
+  this._disabled = false
+  if (this._tty) {
+    this._enableEvents()
+  }
+  if (this._showing) {
+    this.show()
+  }
+}
+
+Gauge.prototype.disable = function () {
+  if (this._disabled) {
+    return
+  }
+  if (this._showing) {
+    this._lastUpdateAt = null
+    this._showing = false
+    this._doRedraw()
+    this._showing = true
+  }
+  this._disabled = true
+  if (this._tty) {
+    this._disableEvents()
+  }
+}
+
+Gauge.prototype._enableEvents = function () {
+  if (this._cleanupOnExit) {
+    this._removeOnExit = onExit(callWith(this, this.disable))
+  }
+  this._tty.on('resize', this._$$handleSizeChange)
+  if (this._fixedFramerate) {
+    this.redrawTracker = setInterval(this._$$doRedraw, this._updateInterval)
+    if (this.redrawTracker.unref) {
+      this.redrawTracker.unref()
+    }
+  }
+}
+
+Gauge.prototype._disableEvents = function () {
+  this._tty.removeListener('resize', this._$$handleSizeChange)
+  if (this._fixedFramerate) {
+    clearInterval(this.redrawTracker)
+  }
+  if (this._removeOnExit) {
+    this._removeOnExit()
+  }
+}
+
+Gauge.prototype.hide = function (cb) {
+  if (this._disabled) {
+    return cb && process.nextTick(cb)
+  }
+  if (!this._showing) {
+    return cb && process.nextTick(cb)
+  }
+  this._showing = false
+  this._doRedraw()
+  cb && setImmediate(cb)
+}
+
+Gauge.prototype.show = function (section, completed) {
+  this._showing = true
+  if (typeof section === 'string') {
+    this._status.section = section
+  } else if (typeof section === 'object') {
+    var sectionKeys = Object.keys(section)
+    for (var ii = 0; ii < sectionKeys.length; ++ii) {
+      var key = sectionKeys[ii]
+      this._status[key] = section[key]
+    }
+  }
+  if (completed != null) {
+    this._status.completed = completed
+  }
+  if (this._disabled) {
+    return
+  }
+  this._requestRedraw()
+}
+
+Gauge.prototype.pulse = function (subsection) {
+  this._status.subsection = subsection || ''
+  this._status.spun++
+  if (this._disabled) {
+    return
+  }
+  if (!this._showing) {
+    return
+  }
+  this._requestRedraw()
+}
+
+Gauge.prototype._handleSizeChange = function () {
+  this._gauge.setWidth(this._tty.columns - 1)
+  this._requestRedraw()
+}
+
+Gauge.prototype._doRedraw = function () {
+  if (this._disabled || this._paused) {
+    return
+  }
+  if (!this._fixedFramerate) {
+    var now = Date.now()
+    if (this._lastUpdateAt && now - this._lastUpdateAt < this._updateInterval) {
+      return
+    }
+    this._lastUpdateAt = now
+  }
+  if (!this._showing && this._onScreen) {
+    this._onScreen = false
+    var result = this._gauge.hide()
+    if (this._hideCursor) {
+      result += this._gauge.showCursor()
+    }
+    return this._writeTo.write(result)
+  }
+  if (!this._showing && !this._onScreen) {
+    return
+  }
+  if (this._showing && !this._onScreen) {
+    this._onScreen = true
+    this._needsRedraw = true
+    if (this._hideCursor) {
+      this._writeTo.write(this._gauge.hideCursor())
+    }
+  }
+  if (!this._needsRedraw) {
+    return
+  }
+  if (!this._writeTo.write(this._gauge.show(this._status))) {
+    this._paused = true
+    this._writeTo.on('drain', callWith(this, function () {
+      this._paused = false
+      this._doRedraw()
+    }))
+  }
+}
diff --git a/server/node_modules/gauge/lib/plumbing.js b/server/node_modules/gauge/lib/plumbing.js
new file mode 100644
index 0000000..c4dc3e0
--- /dev/null
+++ b/server/node_modules/gauge/lib/plumbing.js
@@ -0,0 +1,50 @@
+'use strict'
+var consoleControl = require('console-control-strings')
+var renderTemplate = require('./render-template.js')
+var validate = require('aproba')
+
+var Plumbing = module.exports = function (theme, template, width) {
+  if (!width) {
+    width = 80
+  }
+  validate('OAN', [theme, template, width])
+  this.showing = false
+  this.theme = theme
+  this.width = width
+  this.template = template
+}
+Plumbing.prototype = {}
+
+Plumbing.prototype.setTheme = function (theme) {
+  validate('O', [theme])
+  this.theme = theme
+}
+
+Plumbing.prototype.setTemplate = function (template) {
+  validate('A', [template])
+  this.template = template
+}
+
+Plumbing.prototype.setWidth = function (width) {
+  validate('N', [width])
+  this.width = width
+}
+
+Plumbing.prototype.hide = function () {
+  return consoleControl.gotoSOL() + consoleControl.eraseLine()
+}
+
+Plumbing.prototype.hideCursor = consoleControl.hideCursor
+
+Plumbing.prototype.showCursor = consoleControl.showCursor
+
+Plumbing.prototype.show = function (status) {
+  var values = Object.create(this.theme)
+  for (var key in status) {
+    values[key] = status[key]
+  }
+
+  return renderTemplate(this.width, this.template, values).trim() +
+         consoleControl.color('reset') +
+         consoleControl.eraseLine() + consoleControl.gotoSOL()
+}
diff --git a/server/node_modules/gauge/lib/process.js b/server/node_modules/gauge/lib/process.js
new file mode 100644
index 0000000..05e8569
--- /dev/null
+++ b/server/node_modules/gauge/lib/process.js
@@ -0,0 +1,3 @@
+'use strict'
+// this exists so we can replace it during testing
+module.exports = process
diff --git a/server/node_modules/gauge/lib/progress-bar.js b/server/node_modules/gauge/lib/progress-bar.js
new file mode 100644
index 0000000..184ff25
--- /dev/null
+++ b/server/node_modules/gauge/lib/progress-bar.js
@@ -0,0 +1,41 @@
+'use strict'
+var validate = require('aproba')
+var renderTemplate = require('./render-template.js')
+var wideTruncate = require('./wide-truncate')
+var stringWidth = require('string-width')
+
+module.exports = function (theme, width, completed) {
+  validate('ONN', [theme, width, completed])
+  if (completed < 0) {
+    completed = 0
+  }
+  if (completed > 1) {
+    completed = 1
+  }
+  if (width <= 0) {
+    return ''
+  }
+  var sofar = Math.round(width * completed)
+  var rest = width - sofar
+  var template = [
+    { type: 'complete', value: repeat(theme.complete, sofar), length: sofar },
+    { type: 'remaining', value: repeat(theme.remaining, rest), length: rest },
+  ]
+  return renderTemplate(width, template, theme)
+}
+
+// lodash's way of repeating
+function repeat (string, width) {
+  var result = ''
+  var n = width
+  do {
+    if (n % 2) {
+      result += string
+    }
+    n = Math.floor(n / 2)
+    /* eslint no-self-assign: 0 */
+    string += string
+  } while (n && stringWidth(result) < width)
+
+  return wideTruncate(result, width)
+}
diff --git a/server/node_modules/gauge/lib/render-template.js b/server/node_modules/gauge/lib/render-template.js
new file mode 100644
index 0000000..d1b52c0
--- /dev/null
+++ b/server/node_modules/gauge/lib/render-template.js
@@ -0,0 +1,222 @@
+'use strict'
+var align = require('wide-align')
+var validate = require('aproba')
+var wideTruncate = require('./wide-truncate')
+var error = require('./error')
+var TemplateItem = require('./template-item')
+
+function renderValueWithValues (values) {
+  return function (item) {
+    return renderValue(item, values)
+  }
+}
+
+var renderTemplate = module.exports = function (width, template, values) {
+  var items = prepareItems(width, template, values)
+  var rendered = items.map(renderValueWithValues(values)).join('')
+  return align.left(wideTruncate(rendered, width), width)
+}
+
+function preType (item) {
+  var cappedTypeName = item.type[0].toUpperCase() + item.type.slice(1)
+  return 'pre' + cappedTypeName
+}
+
+function postType (item) {
+  var cappedTypeName = item.type[0].toUpperCase() + item.type.slice(1)
+  return 'post' + cappedTypeName
+}
+
+function hasPreOrPost (item, values) {
+  if (!item.type) {
+    return
+  }
+  return values[preType(item)] || values[postType(item)]
+}
+
+function generatePreAndPost (baseItem, parentValues) {
+  var item = Object.assign({}, baseItem)
+  var values = Object.create(parentValues)
+  var template = []
+  var pre = preType(item)
+  var post = postType(item)
+  if (values[pre]) {
+    template.push({ value: values[pre] })
+    values[pre] = null
+  }
+  item.minLength = null
+  item.length = null
+  item.maxLength = null
+  template.push(item)
+  values[item.type] = values[item.type]
+  if (values[post]) {
+    template.push({ value: values[post] })
+    values[post] = null
+  }
+  return function ($1, $2, length) {
+    return renderTemplate(length, template, values)
+  }
+}
+
+function prepareItems (width, template, values) {
+  function cloneAndObjectify (item, index, arr) {
+    var cloned = new TemplateItem(item, width)
+    var type = cloned.type
+    if (cloned.value == null) {
+      if (!(type in values)) {
+        if (cloned.default == null) {
+          throw new error.MissingTemplateValue(cloned, values)
+        } else {
+          cloned.value = cloned.default
+        }
+      } else {
+        cloned.value = values[type]
+      }
+    }
+    if (cloned.value == null || cloned.value === '') {
+      return null
+    }
+    cloned.index = index
+    cloned.first = index === 0
+    cloned.last = index === arr.length - 1
+    if (hasPreOrPost(cloned, values)) {
+      cloned.value = generatePreAndPost(cloned, values)
+    }
+    return cloned
+  }
+
+  var output = template.map(cloneAndObjectify).filter(function (item) {
+    return item != null
+  })
+
+  var remainingSpace = width
+  var variableCount = output.length
+
+  function consumeSpace (length) {
+    if (length > remainingSpace) {
+      length = remainingSpace
+    }
+    remainingSpace -= length
+  }
+
+  function finishSizing (item, length) {
+    if (item.finished) {
+      throw new error.Internal('Tried to finish template item that was already finished')
+    }
+    if (length === Infinity) {
+      throw new error.Internal('Length of template item cannot be infinity')
+    }
+    if (length != null) {
+      item.length = length
+    }
+    item.minLength = null
+    item.maxLength = null
+    --variableCount
+    item.finished = true
+    if (item.length == null) {
+      item.length = item.getBaseLength()
+    }
+    if (item.length == null) {
+      throw new error.Internal('Finished template items must have a length')
+    }
+    consumeSpace(item.getLength())
+  }
+
+  output.forEach(function (item) {
+    if (!item.kerning) {
+      return
+    }
+    var prevPadRight = item.first ? 0 : output[item.index - 1].padRight
+    if (!item.first && prevPadRight < item.kerning) {
+      item.padLeft = item.kerning - prevPadRight
+    }
+    if (!item.last) {
+      item.padRight = item.kerning
+    }
+  })
+
+  // Finish any that have a fixed (literal or intuited) length
+  output.forEach(function (item) {
+    if (item.getBaseLength() == null) {
+      return
+    }
+    finishSizing(item)
+  })
+
+  var resized = 0
+  var resizing
+  var hunkSize
+  do {
+    resizing = false
+    hunkSize = Math.round(remainingSpace / variableCount)
+    output.forEach(function (item) {
+      if (item.finished) {
+        return
+      }
+      if (!item.maxLength) {
+        return
+      }
+      if (item.getMaxLength() < hunkSize) {
+        finishSizing(item, item.maxLength)
+        resizing = true
+      }
+    })
+  } while (resizing && resized++ < output.length)
+  if (resizing) {
+    throw new error.Internal('Resize loop iterated too many times while determining maxLength')
+  }
+
+  resized = 0
+  do {
+    resizing = false
+    hunkSize = Math.round(remainingSpace / variableCount)
+    output.forEach(function (item) {
+      if (item.finished) {
+        return
+      }
+      if (!item.minLength) {
+        return
+      }
+      if (item.getMinLength() >= hunkSize) {
+        finishSizing(item, item.minLength)
+        resizing = true
+      }
+    })
+  } while (resizing && resized++ < output.length)
+  if (resizing) {
+    throw new error.Internal('Resize loop iterated too many times while determining minLength')
+  }
+
+  hunkSize = Math.round(remainingSpace / variableCount)
+  output.forEach(function (item) {
+    if (item.finished) {
+      return
+    }
+    finishSizing(item, hunkSize)
+  })
+
+  return output
+}
+
+function renderFunction (item, values, length) {
+  validate('OON', arguments)
+  if (item.type) {
+    return item.value(values, values[item.type + 'Theme'] || {}, length)
+  } else {
+    return item.value(values, {}, length)
+  }
+}
+
+function renderValue (item, values) {
+  var length = item.getBaseLength()
+  var value = typeof item.value === 'function' ? renderFunction(item, values, length) : item.value
+  if (value == null || value === '') {
+    return ''
+  }
+  var alignWith = align[item.align] || align.left
+  var leftPadding = item.padLeft ? align.left('', item.padLeft) : ''
+  var rightPadding = item.padRight ? align.right('', item.padRight) : ''
+  var truncated = wideTruncate(String(value), length)
+  var aligned = alignWith(truncated, length)
+  return leftPadding + aligned + rightPadding
+}
diff --git a/server/node_modules/gauge/lib/set-immediate.js b/server/node_modules/gauge/lib/set-immediate.js
new file mode 100644
index 0000000..6650a48
--- /dev/null
+++ b/server/node_modules/gauge/lib/set-immediate.js
@@ -0,0 +1,7 @@
+'use strict'
+var process = require('./process')
+try {
+  module.exports = setImmediate
+} catch (ex) {
+  module.exports = process.nextTick
+}
diff --git a/server/node_modules/gauge/lib/set-interval.js b/server/node_modules/gauge/lib/set-interval.js
new file mode 100644
index 0000000..5761987
--- /dev/null
+++ b/server/node_modules/gauge/lib/set-interval.js
@@ -0,0 +1,3 @@
+'use strict'
+// this exists so we can replace it during testing
+module.exports = setInterval
diff --git a/server/node_modules/gauge/lib/spin.js b/server/node_modules/gauge/lib/spin.js
new file mode 100644
index 0000000..34142ee
--- /dev/null
+++ b/server/node_modules/gauge/lib/spin.js
@@ -0,0 +1,5 @@
+'use strict'
+
+module.exports = function spin (spinstr, spun) {
+  return spinstr[spun % spinstr.length]
+}
diff --git a/server/node_modules/gauge/lib/template-item.js b/server/node_modules/gauge/lib/template-item.js
new file mode 100644
index 0000000..e307e9b
--- /dev/null
+++ b/server/node_modules/gauge/lib/template-item.js
@@ -0,0 +1,87 @@
+'use strict'
+var stringWidth = require('string-width')
+
+module.exports = TemplateItem
+
+function isPercent (num) {
+  if (typeof num !== 'string') {
+    return false
+  }
+  return num.slice(-1) === '%'
+}
+
+function percent (num) {
+  return Number(num.slice(0, -1)) / 100
+}
+
+function TemplateItem (values, outputLength) {
+  this.overallOutputLength = outputLength
+  this.finished = false
+  this.type = null
+  this.value = null
+  this.length = null
+  this.maxLength = null
+  this.minLength = null
+  this.kerning = null
+  this.align = 'left'
+  this.padLeft = 0
+  this.padRight = 0
+  this.index = null
+  this.first = null
+  this.last = null
+  if (typeof values === 'string') {
+    this.value = values
+  } else {
+    for (var prop in values) {
+      this[prop] = values[prop]
+    }
+  }
+  // Realize percents
+  if (isPercent(this.length)) {
+    this.length = Math.round(this.overallOutputLength * percent(this.length))
+  }
+  if (isPercent(this.minLength)) {
+    this.minLength = Math.round(this.overallOutputLength * percent(this.minLength))
+  }
+  if (isPercent(this.maxLength)) {
+    this.maxLength = Math.round(this.overallOutputLength * percent(this.maxLength))
+  }
+  return this
+}
+
+TemplateItem.prototype = {}
+
+TemplateItem.prototype.getBaseLength = function () {
+  var length = this.length
+  if (
+    length == null &&
+    typeof this.value === 'string' &&
+    this.maxLength == null &&
+    this.minLength == null
+  ) {
+    length = stringWidth(this.value)
+  }
+  return length
+}
+
+TemplateItem.prototype.getLength = function () {
+  var length = this.getBaseLength()
+  if (length == null) {
+    return null
+  }
+  return length + this.padLeft + this.padRight
+}
+
+TemplateItem.prototype.getMaxLength = function () {
+  if (this.maxLength == null) {
+    return null
+  }
+  return this.maxLength + this.padLeft + this.padRight
+}
+
+TemplateItem.prototype.getMinLength = function () {
+  if (this.minLength == null) {
+    return null
+  }
+  return this.minLength + this.padLeft + this.padRight
+}
diff --git a/server/node_modules/gauge/lib/theme-set.js b/server/node_modules/gauge/lib/theme-set.js
new file mode 100644
index 0000000..643d7db
--- /dev/null
+++ b/server/node_modules/gauge/lib/theme-set.js
@@ -0,0 +1,122 @@
+'use strict'
+
+module.exports = function () {
+  return ThemeSetProto.newThemeSet()
+}
+
+var ThemeSetProto = {}
+
+ThemeSetProto.baseTheme = require('./base-theme.js')
+
+ThemeSetProto.newTheme = function (parent, theme) {
+  if (!theme) {
+    theme = parent
+    parent = this.baseTheme
+  }
+  return Object.assign({}, parent, theme)
+}
+
+ThemeSetProto.getThemeNames = function () {
+  return Object.keys(this.themes)
+}
+
+ThemeSetProto.addTheme = function (name, parent, theme) {
+  this.themes[name] = this.newTheme(parent, theme)
+}
+
+ThemeSetProto.addToAllThemes = function (theme) {
+  var themes = this.themes
+  Object.keys(themes).forEach(function (name) {
+    Object.assign(themes[name], theme)
+  })
+  Object.assign(this.baseTheme, theme)
+}
+
+ThemeSetProto.getTheme = function (name) {
+  if (!this.themes[name]) {
+    throw this.newMissingThemeError(name)
+  }
+  return this.themes[name]
+}
+
+ThemeSetProto.setDefault = function (opts, name) {
+  if (name == null) {
+    name = opts
+    opts = {}
+  }
+  var platform = opts.platform == null ? 'fallback' : opts.platform
+  var hasUnicode = !!opts.hasUnicode
+  var hasColor = !!opts.hasColor
+  if (!this.defaults[platform]) {
+    this.defaults[platform] = { true: {}, false: {} }
+  }
+  this.defaults[platform][hasUnicode][hasColor] = name
+}
+
+ThemeSetProto.getDefault = function (opts) {
+  if (!opts) {
+    opts = {}
+  }
+  var platformName = opts.platform || process.platform
+  var platform = this.defaults[platformName] || this.defaults.fallback
+  var hasUnicode = !!opts.hasUnicode
+  var hasColor = !!opts.hasColor
+  if (!platform) {
+    throw this.newMissingDefaultThemeError(platformName, hasUnicode, hasColor)
+  }
+  if (!platform[hasUnicode][hasColor]) {
+    if (hasUnicode && hasColor && platform[!hasUnicode][hasColor]) {
+      hasUnicode = false
+    } else if (hasUnicode && hasColor && platform[hasUnicode][!hasColor]) {
+      hasColor = false
+    } else if (hasUnicode && hasColor && platform[!hasUnicode][!hasColor]) {
+      hasUnicode = false
+      hasColor = false
+    } else if (hasUnicode && !hasColor && platform[!hasUnicode][hasColor]) {
+      hasUnicode = false
+    } else if (!hasUnicode && hasColor && platform[hasUnicode][!hasColor]) {
+      hasColor = false
+    } else if (platform === this.defaults.fallback) {
+      throw this.newMissingDefaultThemeError(platformName, hasUnicode, hasColor)
+    }
+  }
+  if (platform[hasUnicode][hasColor]) {
+    return this.getTheme(platform[hasUnicode][hasColor])
+  } else {
+    return this.getDefault(Object.assign({}, opts, { platform: 'fallback' }))
+  }
+}
+
+ThemeSetProto.newMissingThemeError = function newMissingThemeError (name) {
+  var err = new Error('Could not find a gauge theme named "' + name + '"')
+  Error.captureStackTrace.call(err, newMissingThemeError)
+  err.theme = name
+  err.code = 'EMISSINGTHEME'
+  return err
+}
+
+ThemeSetProto.newMissingDefaultThemeError =
+  function newMissingDefaultThemeError (platformName, hasUnicode, hasColor) {
+    var err = new Error(
+      'Could not find a gauge theme for your platform/unicode/color use combo:\n' +
+    '    platform = ' + platformName + '\n' +
+    '    hasUnicode = ' + hasUnicode + '\n' +
+    '    hasColor = ' + hasColor)
+    Error.captureStackTrace.call(err, newMissingDefaultThemeError)
+    err.platform = platformName
+    err.hasUnicode = hasUnicode
+    err.hasColor = hasColor
+    err.code = 'EMISSINGTHEME'
+    return err
+  }
+
+ThemeSetProto.newThemeSet = function () {
+  var themeset = function (opts) {
+    return themeset.getDefault(opts)
+  }
+  return Object.assign(themeset, ThemeSetProto, {
+    themes: Object.assign({}, this.themes),
+    baseTheme: Object.assign({}, this.baseTheme),
+    defaults: JSON.parse(JSON.stringify(this.defaults || {})),
+  })
+}
diff --git a/server/node_modules/gauge/lib/themes.js b/server/node_modules/gauge/lib/themes.js
new file mode 100644
index 0000000..d2e62bb
--- /dev/null
+++ b/server/node_modules/gauge/lib/themes.js
@@ -0,0 +1,56 @@
+'use strict'
+var color = require('console-control-strings').color
+var ThemeSet = require('./theme-set.js')
+
+var themes = module.exports = new ThemeSet()
+
+themes.addTheme('ASCII', {
+  preProgressbar: '[',
+  postProgressbar: ']',
+  progressbarTheme: {
+    complete: '#',
+    remaining: '.',
+  },
+  activityIndicatorTheme: '-\\|/',
+  preSubsection: '>',
+})
+
+themes.addTheme('colorASCII', themes.getTheme('ASCII'), {
+  progressbarTheme: {
+    preComplete: color('bgBrightWhite', 'brightWhite'),
+    complete: '#',
+    postComplete: color('reset'),
+    preRemaining: color('bgBrightBlack', 'brightBlack'),
+    remaining: '.',
+    postRemaining: color('reset'),
+  },
+})
+
+themes.addTheme('brailleSpinner', {
+  preProgressbar: '(',
+  postProgressbar: ')',
+  progressbarTheme: {
+    complete: '#',
+    remaining: '⠂',
+  },
+  activityIndicatorTheme: '⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏',
+  preSubsection: '>',
+})
+
+themes.addTheme('colorBrailleSpinner', themes.getTheme('brailleSpinner'), {
+  progressbarTheme: {
+    preComplete: color('bgBrightWhite', 'brightWhite'),
+    complete: '#',
+    postComplete: color('reset'),
+    preRemaining: color('bgBrightBlack', 'brightBlack'),
+    remaining: '⠂',
+    postRemaining: color('reset'),
+  },
+})
+
+themes.setDefault({}, 'ASCII')
+themes.setDefault({ hasColor: true }, 'colorASCII')
+themes.setDefault({ platform: 'darwin', hasUnicode: true }, 'brailleSpinner')
+themes.setDefault({ platform: 'darwin', hasUnicode: true, hasColor: true }, 'colorBrailleSpinner')
+themes.setDefault({ platform: 'linux', hasUnicode: true }, 'brailleSpinner')
+themes.setDefault({ platform: 'linux', hasUnicode: true, hasColor: true }, 'colorBrailleSpinner')
diff --git a/server/node_modules/gauge/lib/wide-truncate.js b/server/node_modules/gauge/lib/wide-truncate.js
new file mode 100644
index 0000000..5284a69
--- /dev/null
+++ b/server/node_modules/gauge/lib/wide-truncate.js
@@ -0,0 +1,31 @@
+'use strict'
+var stringWidth = require('string-width')
+var stripAnsi = require('strip-ansi')
+
+module.exports = wideTruncate
+
+function wideTruncate (str, target) {
+  if (stringWidth(str) === 0) {
+    return str
+  }
+  if (target <= 0) {
+    return ''
+  }
+  if (stringWidth(str) <= target) {
+    return str
+  }
+
+  // We compute the number of bytes of ansi sequences here and add
+  // that to our initial truncation to ensure that we don't slice one
+  // that we want to keep in half.
+  var noAnsi = stripAnsi(str)
+  var ansiSize = str.length + noAnsi.length
+  var truncated = str.slice(0, target + ansiSize)
+
+  // we have to shrink the result to account for our ansi sequence buffer
+  // (if an ansi sequence was truncated) and double width characters.
+  while (stringWidth(truncated) > target) {
+    truncated = truncated.slice(0, -1)
+  }
+  return truncated
+}
diff --git a/server/node_modules/gauge/package.json b/server/node_modules/gauge/package.json
new file mode 100644
index 0000000..bce3e68
--- /dev/null
+++ b/server/node_modules/gauge/package.json
@@ -0,0 +1,66 @@
+{
+  "name": "gauge",
+  "version": "4.0.4",
+  "description": "A terminal based horizontal gauge",
+  "main": "lib",
+  "scripts": {
+    "test": "tap",
+    "lint": "eslint \"**/*.js\"",
+    "postlint": "template-oss-check",
+    "lintfix": "npm run lint -- --fix",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags",
+    "snap": "tap",
+    "posttest": "npm run lint",
+    "template-oss-apply": "template-oss-apply --force"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/npm/gauge.git"
+  },
+  "keywords": [
+    "progressbar",
+    "progress",
+    "gauge"
+  ],
+  "author": "GitHub Inc.",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/npm/gauge/issues"
+  },
+  "homepage": "https://github.com/npm/gauge",
+  "dependencies": {
+    "aproba": "^1.0.3 || ^2.0.0",
+    "color-support": "^1.1.3",
+    "console-control-strings": "^1.1.0",
+    "has-unicode": "^2.0.1",
+    "signal-exit": "^3.0.7",
+    "string-width": "^4.2.3",
+    "strip-ansi": "^6.0.1",
+    "wide-align": "^1.1.5"
+  },
+  "devDependencies": {
+    "@npmcli/eslint-config": "^3.0.1",
+    "@npmcli/template-oss": "3.2.0",
+    "readable-stream": "^3.6.0",
+    "tap": "^16.0.1"
+  },
+  "files": [
+    "bin/",
+    "lib/"
+  ],
+  "engines": {
+    "node": "^12.13.0 || ^14.15.0 || >=16.0.0"
+  },
+  "tap": {
+    "branches": 79,
+    "statements": 89,
+    "functions": 92,
+    "lines": 90
+  },
+  "templateOSS": {
+    "//@npmcli/template-oss": "This file is partially managed by @npmcli/template-oss. Edits may be overwritten.",
+    "version": "3.2.0"
+  }
+}
diff --git a/server/node_modules/get-intrinsic/.eslintrc b/server/node_modules/get-intrinsic/.eslintrc
new file mode 100644
index 0000000..235fb79
--- /dev/null
+++ b/server/node_modules/get-intrinsic/.eslintrc
@@ -0,0 +1,42 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"env": {
+		"es6": true,
+		"es2017": true,
+		"es2020": true,
+		"es2021": true,
+		"es2022": true,
+	},
+
+	"globals": {
+		"Float16Array": false,
+	},
+
+	"rules": {
+		"array-bracket-newline": 0,
+		"complexity": 0,
+		"eqeqeq": [2, "allow-null"],
+		"func-name-matching": 0,
+		"id-length": 0,
+		"max-lines": 0,
+		"max-lines-per-function": [2, 90],
+		"max-params": [2, 4],
+		"max-statements": 0,
+		"max-statements-per-line": [2, { "max": 2 }],
+		"multiline-comment-style": 0,
+		"no-magic-numbers": 0,
+		"sort-keys": 0,
+	},
+
+	"overrides": [
+		{
+			"files": "test/**",
+			"rules": {
+				"new-cap": 0,
+			},
+		},
+	],
+}
diff --git a/server/node_modules/get-intrinsic/.github/FUNDING.yml b/server/node_modules/get-intrinsic/.github/FUNDING.yml
new file mode 100644
index 0000000..8e8da0d
--- /dev/null
+++ b/server/node_modules/get-intrinsic/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/get-intrinsic
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/get-intrinsic/.nycrc b/server/node_modules/get-intrinsic/.nycrc
new file mode 100644
index 0000000..bdd626c
--- /dev/null
+++ b/server/node_modules/get-intrinsic/.nycrc
@@ -0,0 +1,9 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/get-intrinsic/CHANGELOG.md b/server/node_modules/get-intrinsic/CHANGELOG.md
new file mode 100644
index 0000000..ce1dd98
--- /dev/null
+++ b/server/node_modules/get-intrinsic/CHANGELOG.md
@@ -0,0 +1,186 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.3.0](https://github.com/ljharb/get-intrinsic/compare/v1.2.7...v1.3.0) - 2025-02-22
+
+### Commits
+
+- [Dev Deps] update `es-abstract`, `es-value-fixtures`, `for-each`, `object-inspect` [`9b61553`](https://github.com/ljharb/get-intrinsic/commit/9b61553c587f1c1edbd435597e88c7d387da97dd)
+- [Deps] update `call-bind-apply-helpers`, `es-object-atoms`, `get-proto` [`a341fee`](https://github.com/ljharb/get-intrinsic/commit/a341fee0f39a403b0f0069e82c97642d5eb11043)
+- [New] add `Float16Array` [`de22116`](https://github.com/ljharb/get-intrinsic/commit/de22116b492fb989a0341bceb6e573abfaed73dc)
+
+## [v1.2.7](https://github.com/ljharb/get-intrinsic/compare/v1.2.6...v1.2.7) - 2025-01-02
+
+### Commits
+
+- [Refactor] use `get-proto` directly [`00ab955`](https://github.com/ljharb/get-intrinsic/commit/00ab95546a0980c8ad42a84253daaa8d2adcedf9)
+- [Deps] update `math-intrinsics` [`c716cdd`](https://github.com/ljharb/get-intrinsic/commit/c716cdd6bbe36b438057025561b8bb5a879ac8a0)
+- [Dev Deps] update `call-bound`, `es-abstract` [`dc648a6`](https://github.com/ljharb/get-intrinsic/commit/dc648a67eb359037dff8d8619bfa71d86debccb1)
+
+## [v1.2.6](https://github.com/ljharb/get-intrinsic/compare/v1.2.5...v1.2.6) - 2024-12-11
+
+### Commits
+
+- [Refactor] use `math-intrinsics` [`841be86`](https://github.com/ljharb/get-intrinsic/commit/841be8641a9254c4c75483b30c8871b5d5065926)
+- [Refactor] use `es-object-atoms` [`42057df`](https://github.com/ljharb/get-intrinsic/commit/42057dfa16f66f64787e66482af381cc6f31d2c1)
+- [Deps] update `call-bind-apply-helpers` [`45afa24`](https://github.com/ljharb/get-intrinsic/commit/45afa24a9ee4d6d3c172db1f555b16cb27843ef4)
+- [Dev Deps] update `call-bound` [`9cba9c6`](https://github.com/ljharb/get-intrinsic/commit/9cba9c6e70212bc163b7a5529cb25df46071646f)
+
+## [v1.2.5](https://github.com/ljharb/get-intrinsic/compare/v1.2.4...v1.2.5) - 2024-12-06
+
+### Commits
+
+- [actions] split out node 10-20, and 20+ [`6e2b9dd`](https://github.com/ljharb/get-intrinsic/commit/6e2b9dd23902665681ebe453256ccfe21d7966f0)
+- [Refactor] use `dunder-proto` and `call-bind-apply-helpers` instead of `has-proto` [`c095d17`](https://github.com/ljharb/get-intrinsic/commit/c095d179ad0f4fbfff20c8a3e0cb4fe668018998)
+- [Refactor] use `gopd` [`9841d5b`](https://github.com/ljharb/get-intrinsic/commit/9841d5b35f7ab4fd2d193f0c741a50a077920e90)
+- [Dev Deps] update `@ljharb/eslint-config`, `auto-changelog`, `es-abstract`, `es-value-fixtures`, `gopd`, `mock-property`, `object-inspect`, `tape` [`2d07e01`](https://github.com/ljharb/get-intrinsic/commit/2d07e01310cee2cbaedfead6903df128b1f5d425)
+- [Deps] update `gopd`, `has-proto`, `has-symbols`, `hasown` [`974d8bf`](https://github.com/ljharb/get-intrinsic/commit/974d8bf5baad7939eef35c25cc1dd88c10a30fa6)
+- [Dev Deps] update `call-bind`, `es-abstract`, `tape` [`df9dde1`](https://github.com/ljharb/get-intrinsic/commit/df9dde178186631ab8a3165ede056549918ce4bc)
+- [Refactor] cache `es-define-property` as well [`43ef543`](https://github.com/ljharb/get-intrinsic/commit/43ef543cb02194401420e3a914a4ca9168691926)
+- [Deps] update `has-proto`, `has-symbols`, `hasown` [`ad4949d`](https://github.com/ljharb/get-intrinsic/commit/ad4949d5467316505aad89bf75f9417ed782f7af)
+- [Tests] use `call-bound` directly [`ad5c406`](https://github.com/ljharb/get-intrinsic/commit/ad5c4069774bfe90e520a35eead5fe5ca9d69e80)
+- [Deps] update `has-proto`, `hasown` [`45414ca`](https://github.com/ljharb/get-intrinsic/commit/45414caa312333a2798953682c68f85c550627dd)
+- [Tests] replace `aud` with `npm audit` [`18d3509`](https://github.com/ljharb/get-intrinsic/commit/18d3509f79460e7924da70409ee81e5053087523)
+- [Deps] update `es-define-property` [`aadaa3b`](https://github.com/ljharb/get-intrinsic/commit/aadaa3b2188d77ad9bff394ce5d4249c49eb21f5)
+- [Dev Deps] add missing peer dep [`c296a16`](https://github.com/ljharb/get-intrinsic/commit/c296a16246d0c9a5981944f4cc5cf61fbda0cf6a)
+
+## [v1.2.4](https://github.com/ljharb/get-intrinsic/compare/v1.2.3...v1.2.4) - 2024-02-05
+
+### Commits
+
+- [Refactor] use all 7 <+ ES6 Errors from `es-errors` [`bcac811`](https://github.com/ljharb/get-intrinsic/commit/bcac811abdc1c982e12abf848a410d6aae148d14)
+
+## [v1.2.3](https://github.com/ljharb/get-intrinsic/compare/v1.2.2...v1.2.3) - 2024-02-03
+
+### Commits
+
+- [Refactor] use `es-errors`, so things that only need those do not need `get-intrinsic` [`f11db9c`](https://github.com/ljharb/get-intrinsic/commit/f11db9c4fb97d87bbd53d3c73ac6b3db3613ad3b)
+- [Dev Deps] update `aud`, `es-abstract`, `mock-property`, `npmignore` [`b7ac7d1`](https://github.com/ljharb/get-intrinsic/commit/b7ac7d1616fefb03877b1aed0c8f8d61aad32b6c)
+- [meta] simplify `exports` [`faa0cc6`](https://github.com/ljharb/get-intrinsic/commit/faa0cc618e2830ffb51a8202490b0c215d965cbc)
+- [meta] add missing `engines.node` [`774dd0b`](https://github.com/ljharb/get-intrinsic/commit/774dd0b3e8f741c3f05a6322d124d6087f146af1)
+- [Dev Deps] update `tape` [`5828e8e`](https://github.com/ljharb/get-intrinsic/commit/5828e8e4a04e69312e87a36c0ea39428a7a4c3d8)
+- [Robustness] use null objects for lookups [`eb9a11f`](https://github.com/ljharb/get-intrinsic/commit/eb9a11fa9eb3e13b193fcc05a7fb814341b1a7b7)
+- [meta] add `sideEffects` flag [`89bcc7a`](https://github.com/ljharb/get-intrinsic/commit/89bcc7a42e19bf07b7c21e3094d5ab177109e6d2)
+
+## [v1.2.2](https://github.com/ljharb/get-intrinsic/compare/v1.2.1...v1.2.2) - 2023-10-20
+
+### Commits
+
+- [Dev Deps] update `@ljharb/eslint-config`, `aud`, `call-bind`, `es-abstract`, `mock-property`, `object-inspect`, `tape` [`f51bcf2`](https://github.com/ljharb/get-intrinsic/commit/f51bcf26412d58d17ce17c91c9afd0ad271f0762)
+- [Refactor] use `hasown` instead of `has` [`18d14b7`](https://github.com/ljharb/get-intrinsic/commit/18d14b799bea6b5765e1cec91890830cbcdb0587)
+- [Deps] update `function-bind` [`6e109c8`](https://github.com/ljharb/get-intrinsic/commit/6e109c81e03804cc5e7824fb64353cdc3d8ee2c7)
+
+## [v1.2.1](https://github.com/ljharb/get-intrinsic/compare/v1.2.0...v1.2.1) - 2023-05-13
+
+### Commits
+
+- [Fix] avoid a crash in envs without `__proto__` [`7bad8d0`](https://github.com/ljharb/get-intrinsic/commit/7bad8d061bf8721733b58b73a2565af2b6756b64)
+- [Dev Deps] update `es-abstract` [`c60e6b7`](https://github.com/ljharb/get-intrinsic/commit/c60e6b7b4cf9660c7f27ed970970fd55fac48dc5)
+
+## [v1.2.0](https://github.com/ljharb/get-intrinsic/compare/v1.1.3...v1.2.0) - 2023-01-19
+
+### Commits
+
+- [actions] update checkout action [`ca6b12f`](https://github.com/ljharb/get-intrinsic/commit/ca6b12f31eaacea4ea3b055e744cd61623385ffb)
+- [Dev Deps] update `@ljharb/eslint-config`, `es-abstract`, `object-inspect`, `tape` [`41a3727`](https://github.com/ljharb/get-intrinsic/commit/41a3727d0026fa04273ae216a5f8e12eefd72da8)
+- [Fix] ensure `Error.prototype` is undeniable [`c511e97`](https://github.com/ljharb/get-intrinsic/commit/c511e97ae99c764c4524b540dee7a70757af8da3)
+- [Dev Deps] update `aud`, `es-abstract`, `tape` [`1bef8a8`](https://github.com/ljharb/get-intrinsic/commit/1bef8a8fd439ebb80863199b6189199e0851ac67)
+- [Dev Deps] update `aud`, `es-abstract` [`0d41f16`](https://github.com/ljharb/get-intrinsic/commit/0d41f16bcd500bc28b7bfc98043ebf61ea081c26)
+- [New] add `BigInt64Array` and `BigUint64Array` [`a6cca25`](https://github.com/ljharb/get-intrinsic/commit/a6cca25f29635889b7e9bd669baf9e04be90e48c)
+- [Tests] use `gopd` [`ecf7722`](https://github.com/ljharb/get-intrinsic/commit/ecf7722240d15cfd16edda06acf63359c10fb9bd)
+
+## [v1.1.3](https://github.com/ljharb/get-intrinsic/compare/v1.1.2...v1.1.3) - 2022-09-12
+
+### Commits
+
+- [Dev Deps] update `es-abstract`, `es-value-fixtures`, `tape` [`07ff291`](https://github.com/ljharb/get-intrinsic/commit/07ff291816406ebe5a12d7f16965bde0942dd688)
+- [Fix] properly check for % signs [`50ac176`](https://github.com/ljharb/get-intrinsic/commit/50ac1760fe99c227e64eabde76e9c0e44cd881b5)
+
+## [v1.1.2](https://github.com/ljharb/get-intrinsic/compare/v1.1.1...v1.1.2) - 2022-06-08
+
+### Fixed
+
+- [Fix] properly validate against extra % signs [`#16`](https://github.com/ljharb/get-intrinsic/issues/16)
+
+### Commits
+
+- [actions] reuse common workflows [`0972547`](https://github.com/ljharb/get-intrinsic/commit/0972547efd0abc863fe4c445a6ca7eb4f8c6901d)
+- [meta] use `npmignore` to autogenerate an npmignore file [`5ba0b51`](https://github.com/ljharb/get-intrinsic/commit/5ba0b51d8d8d4f1c31d426d74abc0770fd106bad)
+- [actions] use `node/install` instead of `node/run`; use `codecov` action [`c364492`](https://github.com/ljharb/get-intrinsic/commit/c364492af4af51333e6f81c0bf21fd3d602c3661)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `auto-changelog`, `es-abstract`, `object-inspect`, `tape` [`dc04dad`](https://github.com/ljharb/get-intrinsic/commit/dc04dad86f6e5608775a2640cb0db5927ae29ed9)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `es-abstract`, `object-inspect`, `safe-publish-latest`, `tape` [`1c14059`](https://github.com/ljharb/get-intrinsic/commit/1c1405984e86dd2dc9366c15d8a0294a96a146a5)
+- [Tests] use `mock-property` [`b396ef0`](https://github.com/ljharb/get-intrinsic/commit/b396ef05bb73b1d699811abd64b0d9b97997fdda)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `auto-changelog`, `object-inspect`, `tape` [`c2c758d`](https://github.com/ljharb/get-intrinsic/commit/c2c758d3b90af4fef0a76910d8d3c292ec8d1d3e)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `es-abstract`, `es-value-fixtures`, `object-inspect`, `tape` [`29e3c09`](https://github.com/ljharb/get-intrinsic/commit/29e3c091c2bf3e17099969847e8729d0e46896de)
+- [actions] update codecov uploader [`8cbc141`](https://github.com/ljharb/get-intrinsic/commit/8cbc1418940d7a8941f3a7985cbc4ac095c5e13d)
+- [Dev Deps] update `@ljharb/eslint-config`, `es-abstract`, `es-value-fixtures`, `object-inspect`, `tape` [`10b6f5c`](https://github.com/ljharb/get-intrinsic/commit/10b6f5c02593fb3680c581d696ac124e30652932)
+- [readme] add github actions/codecov badges [`4e25400`](https://github.com/ljharb/get-intrinsic/commit/4e25400d9f51ae9eb059cbe22d9144e70ea214e8)
+- [Tests] use `for-each` instead of `foreach` [`c05b957`](https://github.com/ljharb/get-intrinsic/commit/c05b957ad9a7bc7721af7cc9e9be1edbfe057496)
+- [Dev Deps] update `es-abstract` [`29b05ae`](https://github.com/ljharb/get-intrinsic/commit/29b05aec3e7330e9ad0b8e0f685a9112c20cdd97)
+- [meta] use `prepublishOnly` script for npm 7+ [`95c285d`](https://github.com/ljharb/get-intrinsic/commit/95c285da810516057d3bbfa871176031af38f05d)
+- [Deps] update `has-symbols` [`593cb4f`](https://github.com/ljharb/get-intrinsic/commit/593cb4fb38e7922e40e42c183f45274b636424cd)
+- [readme] fix repo URLs [`1c8305b`](https://github.com/ljharb/get-intrinsic/commit/1c8305b5365827c9b6fc785434aac0e1328ff2f5)
+- [Deps] update `has-symbols` [`c7138b6`](https://github.com/ljharb/get-intrinsic/commit/c7138b6c6d73132d859471fb8c13304e1e7c8b20)
+- [Dev Deps] remove unused `has-bigints` [`bd63aff`](https://github.com/ljharb/get-intrinsic/commit/bd63aff6ad8f3a986c557fcda2914187bdaab359)
+
+## [v1.1.1](https://github.com/ljharb/get-intrinsic/compare/v1.1.0...v1.1.1) - 2021-02-03
+
+### Fixed
+
+- [meta] export `./package.json` [`#9`](https://github.com/ljharb/get-intrinsic/issues/9)
+
+### Commits
+
+- [readme] flesh out the readme; use `evalmd` [`d12f12c`](https://github.com/ljharb/get-intrinsic/commit/d12f12c15345a0a0772cc65a7c64369529abd614)
+- [eslint] set up proper globals config [`5a8c098`](https://github.com/ljharb/get-intrinsic/commit/5a8c0984e3319d1ac0e64b102f8ec18b64e79f36)
+- [Dev Deps] update `eslint` [`7b9a5c0`](https://github.com/ljharb/get-intrinsic/commit/7b9a5c0d31a90ca1a1234181c74988fb046701cd)
+
+## [v1.1.0](https://github.com/ljharb/get-intrinsic/compare/v1.0.2...v1.1.0) - 2021-01-25
+
+### Fixed
+
+- [Refactor] delay `Function` eval until syntax-derived values are requested [`#3`](https://github.com/ljharb/get-intrinsic/issues/3)
+
+### Commits
+
+- [Tests] migrate tests to Github Actions [`2ab762b`](https://github.com/ljharb/get-intrinsic/commit/2ab762b48164aea8af37a40ba105bbc8246ab8c4)
+- [meta] do not publish github action workflow files [`5e7108e`](https://github.com/ljharb/get-intrinsic/commit/5e7108e4768b244d48d9567ba4f8a6cab9c65b8e)
+- [Tests] add some coverage [`01ac7a8`](https://github.com/ljharb/get-intrinsic/commit/01ac7a87ac29738567e8524cd8c9e026b1fa8cb3)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `call-bind`, `es-abstract`, `tape`; add `call-bind` [`911b672`](https://github.com/ljharb/get-intrinsic/commit/911b672fbffae433a96924c6ce013585e425f4b7)
+- [Refactor] rearrange evalled constructors a bit [`7e7e4bf`](https://github.com/ljharb/get-intrinsic/commit/7e7e4bf583f3799c8ac1c6c5e10d2cb553957347)
+- [meta] add Automatic Rebase and Require Allow Edits workflows [`0199968`](https://github.com/ljharb/get-intrinsic/commit/01999687a263ffce0a3cb011dfbcb761754aedbc)
+
+## [v1.0.2](https://github.com/ljharb/get-intrinsic/compare/v1.0.1...v1.0.2) - 2020-12-17
+
+### Commits
+
+- [Fix] Throw for non‑existent intrinsics [`68f873b`](https://github.com/ljharb/get-intrinsic/commit/68f873b013c732a05ad6f5fc54f697e55515461b)
+- [Fix] Throw for non‑existent segments in the intrinsic path [`8325dee`](https://github.com/ljharb/get-intrinsic/commit/8325deee43128f3654d3399aa9591741ebe17b21)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `has-bigints`, `object-inspect` [`0c227a7`](https://github.com/ljharb/get-intrinsic/commit/0c227a7d8b629166f25715fd242553892e458525)
+- [meta] do not lint coverage output [`70d2419`](https://github.com/ljharb/get-intrinsic/commit/70d24199b620043cd9110fc5f426d214ebe21dc9)
+
+## [v1.0.1](https://github.com/ljharb/get-intrinsic/compare/v1.0.0...v1.0.1) - 2020-10-30
+
+### Commits
+
+- [Tests] gather coverage data on every job [`d1d280d`](https://github.com/ljharb/get-intrinsic/commit/d1d280dec714e3f0519cc877dbcb193057d9cac6)
+- [Fix] add missing dependencies [`5031771`](https://github.com/ljharb/get-intrinsic/commit/5031771bb1095b38be88ce7c41d5de88718e432e)
+- [Tests] use `es-value-fixtures` [`af48765`](https://github.com/ljharb/get-intrinsic/commit/af48765a23c5323fb0b6b38dbf00eb5099c7bebc)
+
+## v1.0.0 - 2020-10-29
+
+### Commits
+
+- Implementation [`bbce57c`](https://github.com/ljharb/get-intrinsic/commit/bbce57c6f33d05b2d8d3efa273ceeb3ee01127bb)
+- Tests [`17b4f0d`](https://github.com/ljharb/get-intrinsic/commit/17b4f0d56dea6b4059b56fc30ef3ee4d9500ebc2)
+- Initial commit [`3153294`](https://github.com/ljharb/get-intrinsic/commit/31532948de363b0a27dd9fd4649e7b7028ec4b44)
+- npm init [`fb326c4`](https://github.com/ljharb/get-intrinsic/commit/fb326c4d2817c8419ec31de1295f06bb268a7902)
+- [meta] add Automatic Rebase and Require Allow Edits workflows [`48862fb`](https://github.com/ljharb/get-intrinsic/commit/48862fb2508c8f6a57968e6d08b7c883afc9d550)
+- [meta] add `auto-changelog` [`5f28ad0`](https://github.com/ljharb/get-intrinsic/commit/5f28ad019e060a353d8028f9f2591a9cc93074a1)
+- [meta] add "funding"; create `FUNDING.yml` [`c2bbdde`](https://github.com/ljharb/get-intrinsic/commit/c2bbddeba73a875be61484ee4680b129a6d4e0a1)
+- [Tests] add `npm run lint` [`0a84b98`](https://github.com/ljharb/get-intrinsic/commit/0a84b98b22b7cf7a748666f705b0003a493c35fd)
+- Only apps should have lockfiles [`9586c75`](https://github.com/ljharb/get-intrinsic/commit/9586c75866c1ee678e4d5d4dbbdef6997e511b05)
diff --git a/server/node_modules/get-intrinsic/LICENSE b/server/node_modules/get-intrinsic/LICENSE
new file mode 100644
index 0000000..48f05d0
--- /dev/null
+++ b/server/node_modules/get-intrinsic/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/get-intrinsic/README.md b/server/node_modules/get-intrinsic/README.md
new file mode 100644
index 0000000..3aa0bba
--- /dev/null
+++ b/server/node_modules/get-intrinsic/README.md
@@ -0,0 +1,71 @@
+# get-intrinsic <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![dependency status][deps-svg]][deps-url]
+[![dev dependency status][dev-deps-svg]][dev-deps-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+Get and robustly cache all JS language-level intrinsics at first require time.
+
+See the syntax described [in the JS spec](https://tc39.es/ecma262/#sec-well-known-intrinsic-objects) for reference.
+
+## Example
+
+```js
+var GetIntrinsic = require('get-intrinsic');
+var assert = require('assert');
+
+// static methods
+assert.equal(GetIntrinsic('%Math.pow%'), Math.pow);
+assert.equal(Math.pow(2, 3), 8);
+assert.equal(GetIntrinsic('%Math.pow%')(2, 3), 8);
+delete Math.pow;
+assert.equal(GetIntrinsic('%Math.pow%')(2, 3), 8);
+
+// instance methods
+var arr = [1];
+assert.equal(GetIntrinsic('%Array.prototype.push%'), Array.prototype.push);
+assert.deepEqual(arr, [1]);
+
+arr.push(2);
+assert.deepEqual(arr, [1, 2]);
+
+GetIntrinsic('%Array.prototype.push%').call(arr, 3);
+assert.deepEqual(arr, [1, 2, 3]);
+
+delete Array.prototype.push;
+GetIntrinsic('%Array.prototype.push%').call(arr, 4);
+assert.deepEqual(arr, [1, 2, 3, 4]);
+
+// missing features
+delete JSON.parse; // to simulate a real intrinsic that is missing in the environment
+assert.throws(() => GetIntrinsic('%JSON.parse%'));
+assert.equal(undefined, GetIntrinsic('%JSON.parse%', true));
+```
+
+## Tests
+Simply clone the repo, `npm install`, and run `npm test`
+
+## Security
+
+Please email [@ljharb](https://github.com/ljharb) or see https://tidelift.com/security if you have a potential security vulnerability to report.
+
+[package-url]: https://npmjs.org/package/get-intrinsic
+[npm-version-svg]: https://versionbadg.es/ljharb/get-intrinsic.svg
+[deps-svg]: https://david-dm.org/ljharb/get-intrinsic.svg
+[deps-url]: https://david-dm.org/ljharb/get-intrinsic
+[dev-deps-svg]: https://david-dm.org/ljharb/get-intrinsic/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/get-intrinsic#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/get-intrinsic.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/get-intrinsic.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/get-intrinsic.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=get-intrinsic
+[codecov-image]: https://codecov.io/gh/ljharb/get-intrinsic/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/get-intrinsic/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/get-intrinsic
+[actions-url]: https://github.com/ljharb/get-intrinsic/actions
diff --git a/server/node_modules/get-intrinsic/index.js b/server/node_modules/get-intrinsic/index.js
new file mode 100644
index 0000000..bd1d94b
--- /dev/null
+++ b/server/node_modules/get-intrinsic/index.js
@@ -0,0 +1,378 @@
+'use strict';
+
+var undefined;
+
+var $Object = require('es-object-atoms');
+
+var $Error = require('es-errors');
+var $EvalError = require('es-errors/eval');
+var $RangeError = require('es-errors/range');
+var $ReferenceError = require('es-errors/ref');
+var $SyntaxError = require('es-errors/syntax');
+var $TypeError = require('es-errors/type');
+var $URIError = require('es-errors/uri');
+
+var abs = require('math-intrinsics/abs');
+var floor = require('math-intrinsics/floor');
+var max = require('math-intrinsics/max');
+var min = require('math-intrinsics/min');
+var pow = require('math-intrinsics/pow');
+var round = require('math-intrinsics/round');
+var sign = require('math-intrinsics/sign');
+
+var $Function = Function;
+
+// eslint-disable-next-line consistent-return
+var getEvalledConstructor = function (expressionSyntax) {
+	try {
+		return $Function('"use strict"; return (' + expressionSyntax + ').constructor;')();
+	} catch (e) {}
+};
+
+var $gOPD = require('gopd');
+var $defineProperty = require('es-define-property');
+
+var throwTypeError = function () {
+	throw new $TypeError();
+};
+var ThrowTypeError = $gOPD
+	? (function () {
+		try {
+			// eslint-disable-next-line no-unused-expressions, no-caller, no-restricted-properties
+			arguments.callee; // IE 8 does not throw here
+			return throwTypeError;
+		} catch (calleeThrows) {
+			try {
+				// IE 8 throws on Object.getOwnPropertyDescriptor(arguments, '')
+				return $gOPD(arguments, 'callee').get;
+			} catch (gOPDthrows) {
+				return throwTypeError;
+			}
+		}
+	}())
+	: throwTypeError;
+
+var hasSymbols = require('has-symbols')();
+
+var getProto = require('get-proto');
+var $ObjectGPO = require('get-proto/Object.getPrototypeOf');
+var $ReflectGPO = require('get-proto/Reflect.getPrototypeOf');
+
+var $apply = require('call-bind-apply-helpers/functionApply');
+var $call = require('call-bind-apply-helpers/functionCall');
+
+var needsEval = {};
+
+var TypedArray = typeof Uint8Array === 'undefined' || !getProto ? undefined : getProto(Uint8Array);
+
+var INTRINSICS = {
+	__proto__: null,
+	'%AggregateError%': typeof AggregateError === 'undefined' ? undefined : AggregateError,
+	'%Array%': Array,
+	'%ArrayBuffer%': typeof ArrayBuffer === 'undefined' ? undefined : ArrayBuffer,
+	'%ArrayIteratorPrototype%': hasSymbols && getProto ? getProto([][Symbol.iterator]()) : undefined,
+	'%AsyncFromSyncIteratorPrototype%': undefined,
+	'%AsyncFunction%': needsEval,
+	'%AsyncGenerator%': needsEval,
+	'%AsyncGeneratorFunction%': needsEval,
+	'%AsyncIteratorPrototype%': needsEval,
+	'%Atomics%': typeof Atomics === 'undefined' ? undefined : Atomics,
+	'%BigInt%': typeof BigInt === 'undefined' ? undefined : BigInt,
+	'%BigInt64Array%': typeof BigInt64Array === 'undefined' ? undefined : BigInt64Array,
+	'%BigUint64Array%': typeof BigUint64Array === 'undefined' ? undefined : BigUint64Array,
+	'%Boolean%': Boolean,
+	'%DataView%': typeof DataView === 'undefined' ? undefined : DataView,
+	'%Date%': Date,
+	'%decodeURI%': decodeURI,
+	'%decodeURIComponent%': decodeURIComponent,
+	'%encodeURI%': encodeURI,
+	'%encodeURIComponent%': encodeURIComponent,
+	'%Error%': $Error,
+	'%eval%': eval, // eslint-disable-line no-eval
+	'%EvalError%': $EvalError,
+	'%Float16Array%': typeof Float16Array === 'undefined' ? undefined : Float16Array,
+	'%Float32Array%': typeof Float32Array === 'undefined' ? undefined : Float32Array,
+	'%Float64Array%': typeof Float64Array === 'undefined' ? undefined : Float64Array,
+	'%FinalizationRegistry%': typeof FinalizationRegistry === 'undefined' ? undefined : FinalizationRegistry,
+	'%Function%': $Function,
+	'%GeneratorFunction%': needsEval,
+	'%Int8Array%': typeof Int8Array === 'undefined' ? undefined : Int8Array,
+	'%Int16Array%': typeof Int16Array === 'undefined' ? undefined : Int16Array,
+	'%Int32Array%': typeof Int32Array === 'undefined' ? undefined : Int32Array,
+	'%isFinite%': isFinite,
+	'%isNaN%': isNaN,
+	'%IteratorPrototype%': hasSymbols && getProto ? getProto(getProto([][Symbol.iterator]())) : undefined,
+	'%JSON%': typeof JSON === 'object' ? JSON : undefined,
+	'%Map%': typeof Map === 'undefined' ? undefined : Map,
+	'%MapIteratorPrototype%': typeof Map === 'undefined' || !hasSymbols || !getProto ? undefined : getProto(new Map()[Symbol.iterator]()),
+	'%Math%': Math,
+	'%Number%': Number,
+	'%Object%': $Object,
+	'%Object.getOwnPropertyDescriptor%': $gOPD,
+	'%parseFloat%': parseFloat,
+	'%parseInt%': parseInt,
+	'%Promise%': typeof Promise === 'undefined' ? undefined : Promise,
+	'%Proxy%': typeof Proxy === 'undefined' ? undefined : Proxy,
+	'%RangeError%': $RangeError,
+	'%ReferenceError%': $ReferenceError,
+	'%Reflect%': typeof Reflect === 'undefined' ? undefined : Reflect,
+	'%RegExp%': RegExp,
+	'%Set%': typeof Set === 'undefined' ? undefined : Set,
+	'%SetIteratorPrototype%': typeof Set === 'undefined' || !hasSymbols || !getProto ? undefined : getProto(new Set()[Symbol.iterator]()),
+	'%SharedArrayBuffer%': typeof SharedArrayBuffer === 'undefined' ? undefined : SharedArrayBuffer,
+	'%String%': String,
+	'%StringIteratorPrototype%': hasSymbols && getProto ? getProto(''[Symbol.iterator]()) : undefined,
+	'%Symbol%': hasSymbols ? Symbol : undefined,
+	'%SyntaxError%': $SyntaxError,
+	'%ThrowTypeError%': ThrowTypeError,
+	'%TypedArray%': TypedArray,
+	'%TypeError%': $TypeError,
+	'%Uint8Array%': typeof Uint8Array === 'undefined' ? undefined : Uint8Array,
+	'%Uint8ClampedArray%': typeof Uint8ClampedArray === 'undefined' ? undefined : Uint8ClampedArray,
+	'%Uint16Array%': typeof Uint16Array === 'undefined' ? undefined : Uint16Array,
+	'%Uint32Array%': typeof Uint32Array === 'undefined' ? undefined : Uint32Array,
+	'%URIError%': $URIError,
+	'%WeakMap%': typeof WeakMap === 'undefined' ? undefined : WeakMap,
+	'%WeakRef%': typeof WeakRef === 'undefined' ? undefined : WeakRef,
+	'%WeakSet%': typeof WeakSet === 'undefined' ? undefined : WeakSet,
+
+	'%Function.prototype.call%': $call,
+	'%Function.prototype.apply%': $apply,
+	'%Object.defineProperty%': $defineProperty,
+	'%Object.getPrototypeOf%': $ObjectGPO,
+	'%Math.abs%': abs,
+	'%Math.floor%': floor,
+	'%Math.max%': max,
+	'%Math.min%': min,
+	'%Math.pow%': pow,
+	'%Math.round%': round,
+	'%Math.sign%': sign,
+	'%Reflect.getPrototypeOf%': $ReflectGPO
+};
+
+if (getProto) {
+	try {
+		null.error; // eslint-disable-line no-unused-expressions
+	} catch (e) {
+		// https://github.com/tc39/proposal-shadowrealm/pull/384#issuecomment-1364264229
+		var errorProto = getProto(getProto(e));
+		INTRINSICS['%Error.prototype%'] = errorProto;
+	}
+}
+
+var doEval = function doEval(name) {
+	var value;
+	if (name === '%AsyncFunction%') {
+		value = getEvalledConstructor('async function () {}');
+	} else if (name === '%GeneratorFunction%') {
+		value = getEvalledConstructor('function* () {}');
+	} else if (name === '%AsyncGeneratorFunction%') {
+		value = getEvalledConstructor('async function* () {}');
+	} else if (name === '%AsyncGenerator%') {
+		var fn = doEval('%AsyncGeneratorFunction%');
+		if (fn) {
+			value = fn.prototype;
+		}
+	} else if (name === '%AsyncIteratorPrototype%') {
+		var gen = doEval('%AsyncGenerator%');
+		if (gen && getProto) {
+			value = getProto(gen.prototype);
+		}
+	}
+
+	INTRINSICS[name] = value;
+
+	return value;
+};
+
+var LEGACY_ALIASES = {
+	__proto__: null,
+	'%ArrayBufferPrototype%': ['ArrayBuffer', 'prototype'],
+	'%ArrayPrototype%': ['Array', 'prototype'],
+	'%ArrayProto_entries%': ['Array', 'prototype', 'entries'],
+	'%ArrayProto_forEach%': ['Array', 'prototype', 'forEach'],
+	'%ArrayProto_keys%': ['Array', 'prototype', 'keys'],
+	'%ArrayProto_values%': ['Array', 'prototype', 'values'],
+	'%AsyncFunctionPrototype%': ['AsyncFunction', 'prototype'],
+	'%AsyncGenerator%': ['AsyncGeneratorFunction', 'prototype'],
+	'%AsyncGeneratorPrototype%': ['AsyncGeneratorFunction', 'prototype', 'prototype'],
+	'%BooleanPrototype%': ['Boolean', 'prototype'],
+	'%DataViewPrototype%': ['DataView', 'prototype'],
+	'%DatePrototype%': ['Date', 'prototype'],
+	'%ErrorPrototype%': ['Error', 'prototype'],
+	'%EvalErrorPrototype%': ['EvalError', 'prototype'],
+	'%Float32ArrayPrototype%': ['Float32Array', 'prototype'],
+	'%Float64ArrayPrototype%': ['Float64Array', 'prototype'],
+	'%FunctionPrototype%': ['Function', 'prototype'],
+	'%Generator%': ['GeneratorFunction', 'prototype'],
+	'%GeneratorPrototype%': ['GeneratorFunction', 'prototype', 'prototype'],
+	'%Int8ArrayPrototype%': ['Int8Array', 'prototype'],
+	'%Int16ArrayPrototype%': ['Int16Array', 'prototype'],
+	'%Int32ArrayPrototype%': ['Int32Array', 'prototype'],
+	'%JSONParse%': ['JSON', 'parse'],
+	'%JSONStringify%': ['JSON', 'stringify'],
+	'%MapPrototype%': ['Map', 'prototype'],
+	'%NumberPrototype%': ['Number', 'prototype'],
+	'%ObjectPrototype%': ['Object', 'prototype'],
+	'%ObjProto_toString%': ['Object', 'prototype', 'toString'],
+	'%ObjProto_valueOf%': ['Object', 'prototype', 'valueOf'],
+	'%PromisePrototype%': ['Promise', 'prototype'],
+	'%PromiseProto_then%': ['Promise', 'prototype', 'then'],
+	'%Promise_all%': ['Promise', 'all'],
+	'%Promise_reject%': ['Promise', 'reject'],
+	'%Promise_resolve%': ['Promise', 'resolve'],
+	'%RangeErrorPrototype%': ['RangeError', 'prototype'],
+	'%ReferenceErrorPrototype%': ['ReferenceError', 'prototype'],
+	'%RegExpPrototype%': ['RegExp', 'prototype'],
+	'%SetPrototype%': ['Set', 'prototype'],
+	'%SharedArrayBufferPrototype%': ['SharedArrayBuffer', 'prototype'],
+	'%StringPrototype%': ['String', 'prototype'],
+	'%SymbolPrototype%': ['Symbol', 'prototype'],
+	'%SyntaxErrorPrototype%': ['SyntaxError', 'prototype'],
+	'%TypedArrayPrototype%': ['TypedArray', 'prototype'],
+	'%TypeErrorPrototype%': ['TypeError', 'prototype'],
+	'%Uint8ArrayPrototype%': ['Uint8Array', 'prototype'],
+	'%Uint8ClampedArrayPrototype%': ['Uint8ClampedArray', 'prototype'],
+	'%Uint16ArrayPrototype%': ['Uint16Array', 'prototype'],
+	'%Uint32ArrayPrototype%': ['Uint32Array', 'prototype'],
+	'%URIErrorPrototype%': ['URIError', 'prototype'],
+	'%WeakMapPrototype%': ['WeakMap', 'prototype'],
+	'%WeakSetPrototype%': ['WeakSet', 'prototype']
+};
+
+var bind = require('function-bind');
+var hasOwn = require('hasown');
+var $concat = bind.call($call, Array.prototype.concat);
+var $spliceApply = bind.call($apply, Array.prototype.splice);
+var $replace = bind.call($call, String.prototype.replace);
+var $strSlice = bind.call($call, String.prototype.slice);
+var $exec = bind.call($call, RegExp.prototype.exec);
+
+/* adapted from https://github.com/lodash/lodash/blob/4.17.15/dist/lodash.js#L6735-L6744 */
+var rePropName = /[^%.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\\]|\\.)*?)\2)\]|(?=(?:\.|\[\])(?:\.|\[\]|%$))/g;
+var reEscapeChar = /\$\$?/g; /** Used to match backslashes in property paths. */
+var stringToPath = function stringToPath(string) {
+	var first = $strSlice(string, 0, 1);
+	var last = $strSlice(string, -1);
+	if (first === '%' && last !== '%') {
+		throw new $SyntaxError('invalid intrinsic syntax, expected closing `%`');
+	} else if (last === '%' && first !== '%') {
+		throw new $SyntaxError('invalid intrinsic syntax, expected opening `%`');
+	}
+	var result = [];
+	$replace(string, rePropName, function (match, number, quote, subString) {
+		result[result.length] = quote ? $replace(subString, reEscapeChar, '$1') : number || match;
+	});
+	return result;
+};
+/* end adaptation */
+
+var getBaseIntrinsic = function getBaseIntrinsic(name, allowMissing) {
+	var intrinsicName = name;
+	var alias;
+	if (hasOwn(LEGACY_ALIASES, intrinsicName)) {
+		alias = LEGACY_ALIASES[intrinsicName];
+		intrinsicName = '%' + alias[0] + '%';
+	}
+
+	if (hasOwn(INTRINSICS, intrinsicName)) {
+		var value = INTRINSICS[intrinsicName];
+		if (value === needsEval) {
+			value = doEval(intrinsicName);
+		}
+		if (typeof value === 'undefined' && !allowMissing) {
+			throw new $TypeError('intrinsic ' + name + ' exists, but is not available. Please file an issue!');
+		}
+
+		return {
+			alias: alias,
+			name: intrinsicName,
+			value: value
+		};
+	}
+
+	throw new $SyntaxError('intrinsic ' + name + ' does not exist!');
+};
+
+module.exports = function GetIntrinsic(name, allowMissing) {
+	if (typeof name !== 'string' || name.length === 0) {
+		throw new $TypeError('intrinsic name must be a non-empty string');
+	}
+	if (arguments.length > 1 && typeof allowMissing !== 'boolean') {
+		throw new $TypeError('"allowMissing" argument must be a boolean');
+	}
+
+	if ($exec(/^%?[^%]*%?$/, name) === null) {
+		throw new $SyntaxError('`%` may not be present anywhere but at the beginning and end of the intrinsic name');
+	}
+	var parts = stringToPath(name);
+	var intrinsicBaseName = parts.length > 0 ? parts[0] : '';
+
+	var intrinsic = getBaseIntrinsic('%' + intrinsicBaseName + '%', allowMissing);
+	var intrinsicRealName = intrinsic.name;
+	var value = intrinsic.value;
+	var skipFurtherCaching = false;
+
+	var alias = intrinsic.alias;
+	if (alias) {
+		intrinsicBaseName = alias[0];
+		$spliceApply(parts, $concat([0, 1], alias));
+	}
+
+	for (var i = 1, isOwn = true; i < parts.length; i += 1) {
+		var part = parts[i];
+		var first = $strSlice(part, 0, 1);
+		var last = $strSlice(part, -1);
+		if (
+			(
+				(first === '"' || first === "'" || first === '`')
+				|| (last === '"' || last === "'" || last === '`')
+			)
+			&& first !== last
+		) {
+			throw new $SyntaxError('property names with quotes must have matching quotes');
+		}
+		if (part === 'constructor' || !isOwn) {
+			skipFurtherCaching = true;
+		}
+
+		intrinsicBaseName += '.' + part;
+		intrinsicRealName = '%' + intrinsicBaseName + '%';
+
+		if (hasOwn(INTRINSICS, intrinsicRealName)) {
+			value = INTRINSICS[intrinsicRealName];
+		} else if (value != null) {
+			if (!(part in value)) {
+				if (!allowMissing) {
+					throw new $TypeError('base intrinsic for ' + name + ' exists, but the property is not available.');
+				}
+				return void undefined;
+			}
+			if ($gOPD && (i + 1) >= parts.length) {
+				var desc = $gOPD(value, part);
+				isOwn = !!desc;
+
+				// By convention, when a data property is converted to an accessor
+				// property to emulate a data property that does not suffer from
+				// the override mistake, that accessor's getter is marked with
+				// an `originalValue` property. Here, when we detect this, we
+				// uphold the illusion by pretending to see that original data
+				// property, i.e., returning the value rather than the getter
+				// itself.
+				if (isOwn && 'get' in desc && !('originalValue' in desc.get)) {
+					value = desc.get;
+				} else {
+					value = value[part];
+				}
+			} else {
+				isOwn = hasOwn(value, part);
+				value = value[part];
+			}
+
+			if (isOwn && !skipFurtherCaching) {
+				INTRINSICS[intrinsicRealName] = value;
+			}
+		}
+	}
+	return value;
+};
diff --git a/server/node_modules/get-intrinsic/package.json b/server/node_modules/get-intrinsic/package.json
new file mode 100644
index 0000000..2828e73
--- /dev/null
+++ b/server/node_modules/get-intrinsic/package.json
@@ -0,0 +1,97 @@
+{
+	"name": "get-intrinsic",
+	"version": "1.3.0",
+	"description": "Get and robustly cache all JS language-level intrinsics at first require time",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./package.json": "./package.json"
+	},
+	"sideEffects": false,
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prepublishOnly": "safe-publish-latest",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=.js,.mjs .",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>= 10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/get-intrinsic.git"
+	},
+	"keywords": [
+		"javascript",
+		"ecmascript",
+		"es",
+		"js",
+		"intrinsic",
+		"getintrinsic",
+		"es-abstract"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"funding": {
+		"url": "https://github.com/sponsors/ljharb"
+	},
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/get-intrinsic/issues"
+	},
+	"homepage": "https://github.com/ljharb/get-intrinsic#readme",
+	"dependencies": {
+		"call-bind-apply-helpers": "^1.0.2",
+		"es-define-property": "^1.0.1",
+		"es-errors": "^1.3.0",
+		"es-object-atoms": "^1.1.1",
+		"function-bind": "^1.1.2",
+		"get-proto": "^1.0.1",
+		"gopd": "^1.2.0",
+		"has-symbols": "^1.1.0",
+		"hasown": "^2.0.2",
+		"math-intrinsics": "^1.1.0"
+	},
+	"devDependencies": {
+		"@ljharb/eslint-config": "^21.1.1",
+		"auto-changelog": "^2.5.0",
+		"call-bound": "^1.0.3",
+		"encoding": "^0.1.13",
+		"es-abstract": "^1.23.9",
+		"es-value-fixtures": "^1.7.1",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"for-each": "^0.3.5",
+		"make-async-function": "^1.0.0",
+		"make-async-generator-function": "^1.0.0",
+		"make-generator-function": "^2.0.0",
+		"mock-property": "^1.1.0",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"object-inspect": "^1.13.4",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"testling": {
+		"files": "test/GetIntrinsic.js"
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/get-intrinsic/test/GetIntrinsic.js b/server/node_modules/get-intrinsic/test/GetIntrinsic.js
new file mode 100644
index 0000000..d9c0f30
--- /dev/null
+++ b/server/node_modules/get-intrinsic/test/GetIntrinsic.js
@@ -0,0 +1,274 @@
+'use strict';
+
+var GetIntrinsic = require('../');
+
+var test = require('tape');
+var forEach = require('for-each');
+var debug = require('object-inspect');
+var generatorFns = require('make-generator-function')();
+var asyncFns = require('make-async-function').list();
+var asyncGenFns = require('make-async-generator-function')();
+var mockProperty = require('mock-property');
+
+var callBound = require('call-bound');
+var v = require('es-value-fixtures');
+var $gOPD = require('gopd');
+var DefinePropertyOrThrow = require('es-abstract/2023/DefinePropertyOrThrow');
+
+var $isProto = callBound('%Object.prototype.isPrototypeOf%');
+
+test('export', function (t) {
+	t.equal(typeof GetIntrinsic, 'function', 'it is a function');
+	t.equal(GetIntrinsic.length, 2, 'function has length of 2');
+
+	t.end();
+});
+
+test('throws', function (t) {
+	t['throws'](
+		function () { GetIntrinsic('not an intrinsic'); },
+		SyntaxError,
+		'nonexistent intrinsic throws a syntax error'
+	);
+
+	t['throws'](
+		function () { GetIntrinsic(''); },
+		TypeError,
+		'empty string intrinsic throws a type error'
+	);
+
+	t['throws'](
+		function () { GetIntrinsic('.'); },
+		SyntaxError,
+		'"just a dot" intrinsic throws a syntax error'
+	);
+
+	t['throws'](
+		function () { GetIntrinsic('%String'); },
+		SyntaxError,
+		'Leading % without trailing % throws a syntax error'
+	);
+
+	t['throws'](
+		function () { GetIntrinsic('String%'); },
+		SyntaxError,
+		'Trailing % without leading % throws a syntax error'
+	);
+
+	t['throws'](
+		function () { GetIntrinsic("String['prototype]"); },
+		SyntaxError,
+		'Dynamic property access is disallowed for intrinsics (unterminated string)'
+	);
+
+	t['throws'](
+		function () { GetIntrinsic('%Proxy.prototype.undefined%'); },
+		TypeError,
+		"Throws when middle part doesn't exist (%Proxy.prototype.undefined%)"
+	);
+
+	t['throws'](
+		function () { GetIntrinsic('%Array.prototype%garbage%'); },
+		SyntaxError,
+		'Throws with extra percent signs'
+	);
+
+	t['throws'](
+		function () { GetIntrinsic('%Array.prototype%push%'); },
+		SyntaxError,
+		'Throws with extra percent signs, even on an existing intrinsic'
+	);
+
+	forEach(v.nonStrings, function (nonString) {
+		t['throws'](
+			function () { GetIntrinsic(nonString); },
+			TypeError,
+			debug(nonString) + ' is not a String'
+		);
+	});
+
+	forEach(v.nonBooleans, function (nonBoolean) {
+		t['throws'](
+			function () { GetIntrinsic('%', nonBoolean); },
+			TypeError,
+			debug(nonBoolean) + ' is not a Boolean'
+		);
+	});
+
+	forEach([
+		'toString',
+		'propertyIsEnumerable',
+		'hasOwnProperty'
+	], function (objectProtoMember) {
+		t['throws'](
+			function () { GetIntrinsic(objectProtoMember); },
+			SyntaxError,
+			debug(objectProtoMember) + ' is not an intrinsic'
+		);
+	});
+
+	t.end();
+});
+
+test('base intrinsics', function (t) {
+	t.equal(GetIntrinsic('%Object%'), Object, '%Object% yields Object');
+	t.equal(GetIntrinsic('Object'), Object, 'Object yields Object');
+	t.equal(GetIntrinsic('%Array%'), Array, '%Array% yields Array');
+	t.equal(GetIntrinsic('Array'), Array, 'Array yields Array');
+
+	t.end();
+});
+
+test('dotted paths', function (t) {
+	t.equal(GetIntrinsic('%Object.prototype.toString%'), Object.prototype.toString, '%Object.prototype.toString% yields Object.prototype.toString');
+	t.equal(GetIntrinsic('Object.prototype.toString'), Object.prototype.toString, 'Object.prototype.toString yields Object.prototype.toString');
+	t.equal(GetIntrinsic('%Array.prototype.push%'), Array.prototype.push, '%Array.prototype.push% yields Array.prototype.push');
+	t.equal(GetIntrinsic('Array.prototype.push'), Array.prototype.push, 'Array.prototype.push yields Array.prototype.push');
+
+	test('underscore paths are aliases for dotted paths', { skip: !Object.isFrozen || Object.isFrozen(Object.prototype) }, function (st) {
+		var original = GetIntrinsic('%ObjProto_toString%');
+
+		forEach([
+			'%Object.prototype.toString%',
+			'Object.prototype.toString',
+			'%ObjectPrototype.toString%',
+			'ObjectPrototype.toString',
+			'%ObjProto_toString%',
+			'ObjProto_toString'
+		], function (name) {
+			DefinePropertyOrThrow(Object.prototype, 'toString', {
+				'[[Value]]': function toString() {
+					return original.apply(this, arguments);
+				}
+			});
+			st.equal(GetIntrinsic(name), original, name + ' yields original Object.prototype.toString');
+		});
+
+		DefinePropertyOrThrow(Object.prototype, 'toString', { '[[Value]]': original });
+		st.end();
+	});
+
+	test('dotted paths cache', { skip: !Object.isFrozen || Object.isFrozen(Object.prototype) }, function (st) {
+		var original = GetIntrinsic('%Object.prototype.propertyIsEnumerable%');
+
+		forEach([
+			'%Object.prototype.propertyIsEnumerable%',
+			'Object.prototype.propertyIsEnumerable',
+			'%ObjectPrototype.propertyIsEnumerable%',
+			'ObjectPrototype.propertyIsEnumerable'
+		], function (name) {
+			var restore = mockProperty(Object.prototype, 'propertyIsEnumerable', {
+				value: function propertyIsEnumerable() {
+					return original.apply(this, arguments);
+				}
+			});
+			st.equal(GetIntrinsic(name), original, name + ' yields cached Object.prototype.propertyIsEnumerable');
+
+			restore();
+		});
+
+		st.end();
+	});
+
+	test('dotted path reports correct error', function (st) {
+		st['throws'](function () {
+			GetIntrinsic('%NonExistentIntrinsic.prototype.property%');
+		}, /%NonExistentIntrinsic%/, 'The base intrinsic of %NonExistentIntrinsic.prototype.property% is %NonExistentIntrinsic%');
+
+		st['throws'](function () {
+			GetIntrinsic('%NonExistentIntrinsicPrototype.property%');
+		}, /%NonExistentIntrinsicPrototype%/, 'The base intrinsic of %NonExistentIntrinsicPrototype.property% is %NonExistentIntrinsicPrototype%');
+
+		st.end();
+	});
+
+	t.end();
+});
+
+test('accessors', { skip: !$gOPD || typeof Map !== 'function' }, function (t) {
+	var actual = $gOPD(Map.prototype, 'size');
+	t.ok(actual, 'Map.prototype.size has a descriptor');
+	t.equal(typeof actual.get, 'function', 'Map.prototype.size has a getter function');
+	t.equal(GetIntrinsic('%Map.prototype.size%'), actual.get, '%Map.prototype.size% yields the getter for it');
+	t.equal(GetIntrinsic('Map.prototype.size'), actual.get, 'Map.prototype.size yields the getter for it');
+
+	t.end();
+});
+
+test('generator functions', { skip: !generatorFns.length }, function (t) {
+	var $GeneratorFunction = GetIntrinsic('%GeneratorFunction%');
+	var $GeneratorFunctionPrototype = GetIntrinsic('%Generator%');
+	var $GeneratorPrototype = GetIntrinsic('%GeneratorPrototype%');
+
+	forEach(generatorFns, function (genFn) {
+		var fnName = genFn.name;
+		fnName = fnName ? "'" + fnName + "'" : 'genFn';
+
+		t.ok(genFn instanceof $GeneratorFunction, fnName + ' instanceof %GeneratorFunction%');
+		t.ok($isProto($GeneratorFunctionPrototype, genFn), '%Generator% is prototype of ' + fnName);
+		t.ok($isProto($GeneratorPrototype, genFn.prototype), '%GeneratorPrototype% is prototype of ' + fnName + '.prototype');
+	});
+
+	t.end();
+});
+
+test('async functions', { skip: !asyncFns.length }, function (t) {
+	var $AsyncFunction = GetIntrinsic('%AsyncFunction%');
+	var $AsyncFunctionPrototype = GetIntrinsic('%AsyncFunctionPrototype%');
+
+	forEach(asyncFns, function (asyncFn) {
+		var fnName = asyncFn.name;
+		fnName = fnName ? "'" + fnName + "'" : 'asyncFn';
+
+		t.ok(asyncFn instanceof $AsyncFunction, fnName + ' instanceof %AsyncFunction%');
+		t.ok($isProto($AsyncFunctionPrototype, asyncFn), '%AsyncFunctionPrototype% is prototype of ' + fnName);
+	});
+
+	t.end();
+});
+
+test('async generator functions', { skip: asyncGenFns.length === 0 }, function (t) {
+	var $AsyncGeneratorFunction = GetIntrinsic('%AsyncGeneratorFunction%');
+	var $AsyncGeneratorFunctionPrototype = GetIntrinsic('%AsyncGenerator%');
+	var $AsyncGeneratorPrototype = GetIntrinsic('%AsyncGeneratorPrototype%');
+
+	forEach(asyncGenFns, function (asyncGenFn) {
+		var fnName = asyncGenFn.name;
+		fnName = fnName ? "'" + fnName + "'" : 'asyncGenFn';
+
+		t.ok(asyncGenFn instanceof $AsyncGeneratorFunction, fnName + ' instanceof %AsyncGeneratorFunction%');
+		t.ok($isProto($AsyncGeneratorFunctionPrototype, asyncGenFn), '%AsyncGenerator% is prototype of ' + fnName);
+		t.ok($isProto($AsyncGeneratorPrototype, asyncGenFn.prototype), '%AsyncGeneratorPrototype% is prototype of ' + fnName + '.prototype');
+	});
+
+	t.end();
+});
+
+test('%ThrowTypeError%', function (t) {
+	var $ThrowTypeError = GetIntrinsic('%ThrowTypeError%');
+
+	t.equal(typeof $ThrowTypeError, 'function', 'is a function');
+	t['throws'](
+		$ThrowTypeError,
+		TypeError,
+		'%ThrowTypeError% throws a TypeError'
+	);
+
+	t.end();
+});
+
+test('allowMissing', { skip: asyncGenFns.length > 0 }, function (t) {
+	t['throws'](
+		function () { GetIntrinsic('%AsyncGeneratorPrototype%'); },
+		TypeError,
+		'throws when missing'
+	);
+
+	t.equal(
+		GetIntrinsic('%AsyncGeneratorPrototype%', true),
+		undefined,
+		'does not throw when allowMissing'
+	);
+
+	t.end();
+});
diff --git a/server/node_modules/get-proto/.eslintrc b/server/node_modules/get-proto/.eslintrc
new file mode 100644
index 0000000..1d21a8a
--- /dev/null
+++ b/server/node_modules/get-proto/.eslintrc
@@ -0,0 +1,10 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"id-length": "off",
+		"sort-keys": "off",
+	},
+}
diff --git a/server/node_modules/get-proto/.github/FUNDING.yml b/server/node_modules/get-proto/.github/FUNDING.yml
new file mode 100644
index 0000000..93183ef
--- /dev/null
+++ b/server/node_modules/get-proto/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/get-proto
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/get-proto/.nycrc b/server/node_modules/get-proto/.nycrc
new file mode 100644
index 0000000..bdd626c
--- /dev/null
+++ b/server/node_modules/get-proto/.nycrc
@@ -0,0 +1,9 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/get-proto/CHANGELOG.md b/server/node_modules/get-proto/CHANGELOG.md
new file mode 100644
index 0000000..5860229
--- /dev/null
+++ b/server/node_modules/get-proto/CHANGELOG.md
@@ -0,0 +1,21 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.0.1](https://github.com/ljharb/get-proto/compare/v1.0.0...v1.0.1) - 2025-01-02
+
+### Commits
+
+- [Fix] for the `Object.getPrototypeOf` window, throw for non-objects [`7fe6508`](https://github.com/ljharb/get-proto/commit/7fe6508b71419ebe1976bedb86001d1feaeaa49a)
+
+## v1.0.0 - 2025-01-01
+
+### Commits
+
+- Initial implementation, tests, readme, types [`5c70775`](https://github.com/ljharb/get-proto/commit/5c707751e81c3deeb2cf980d185fc7fd43611415)
+- Initial commit [`7c65c2a`](https://github.com/ljharb/get-proto/commit/7c65c2ad4e33d5dae2f219ebe1a046ae2256972c)
+- npm init [`0b8cf82`](https://github.com/ljharb/get-proto/commit/0b8cf824c9634e4a34ef7dd2a2cdc5be6ac79518)
+- Only apps should have lockfiles [`a6d1bff`](https://github.com/ljharb/get-proto/commit/a6d1bffc364f5828377cea7194558b2dbef7aea2)
diff --git a/server/node_modules/get-proto/LICENSE b/server/node_modules/get-proto/LICENSE
new file mode 100644
index 0000000..eeabd1c
--- /dev/null
+++ b/server/node_modules/get-proto/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/get-proto/Object.getPrototypeOf.d.ts b/server/node_modules/get-proto/Object.getPrototypeOf.d.ts
new file mode 100644
index 0000000..028b3ff
--- /dev/null
+++ b/server/node_modules/get-proto/Object.getPrototypeOf.d.ts
@@ -0,0 +1,5 @@
+declare function getProto<O extends object>(object: O): object | null;
+
+declare const x: typeof getProto | null;
+
+export = x;
\ No newline at end of file
diff --git a/server/node_modules/get-proto/Object.getPrototypeOf.js b/server/node_modules/get-proto/Object.getPrototypeOf.js
new file mode 100644
index 0000000..c2cbbdf
--- /dev/null
+++ b/server/node_modules/get-proto/Object.getPrototypeOf.js
@@ -0,0 +1,6 @@
+'use strict';
+
+var $Object = require('es-object-atoms');
+
+/** @type {import('./Object.getPrototypeOf')} */
+module.exports = $Object.getPrototypeOf || null;
diff --git a/server/node_modules/get-proto/README.md b/server/node_modules/get-proto/README.md
new file mode 100644
index 0000000..f8b4cce
--- /dev/null
+++ b/server/node_modules/get-proto/README.md
@@ -0,0 +1,50 @@
+# get-proto <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+Robustly get the [[Prototype]] of an object. Uses the best available method.
+
+## Getting started
+
+```sh
+npm install --save get-proto
+```
+
+## Usage/Examples
+
+```js
+const assert = require('assert');
+const getProto = require('get-proto');
+
+const a = { a: 1, b: 2, [Symbol.toStringTag]: 'foo' };
+const b = { c: 3, __proto__: a };
+
+assert.equal(getProto(b), a);
+assert.equal(getProto(a), Object.prototype);
+assert.equal(getProto({ __proto__: null }), null);
+```
+
+## Tests
+
+Clone the repo, `npm install`, and run `npm test`
+
+[package-url]: https://npmjs.org/package/get-proto
+[npm-version-svg]: https://versionbadg.es/ljharb/get-proto.svg
+[deps-svg]: https://david-dm.org/ljharb/get-proto.svg
+[deps-url]: https://david-dm.org/ljharb/get-proto
+[dev-deps-svg]: https://david-dm.org/ljharb/get-proto/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/get-proto#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/get-proto.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/get-proto.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/get-proto.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=get-proto
+[codecov-image]: https://codecov.io/gh/ljharb/get-proto/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/get-proto/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/get-proto
+[actions-url]: https://github.com/ljharb/get-proto/actions
diff --git a/server/node_modules/get-proto/Reflect.getPrototypeOf.d.ts b/server/node_modules/get-proto/Reflect.getPrototypeOf.d.ts
new file mode 100644
index 0000000..2388fe0
--- /dev/null
+++ b/server/node_modules/get-proto/Reflect.getPrototypeOf.d.ts
@@ -0,0 +1,3 @@
+declare const x: typeof Reflect.getPrototypeOf | null;
+
+export = x;
\ No newline at end of file
diff --git a/server/node_modules/get-proto/Reflect.getPrototypeOf.js b/server/node_modules/get-proto/Reflect.getPrototypeOf.js
new file mode 100644
index 0000000..e6c51be
--- /dev/null
+++ b/server/node_modules/get-proto/Reflect.getPrototypeOf.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./Reflect.getPrototypeOf')} */
+module.exports = (typeof Reflect !== 'undefined' && Reflect.getPrototypeOf) || null;
diff --git a/server/node_modules/get-proto/index.d.ts b/server/node_modules/get-proto/index.d.ts
new file mode 100644
index 0000000..2c021f3
--- /dev/null
+++ b/server/node_modules/get-proto/index.d.ts
@@ -0,0 +1,5 @@
+declare function getProto<O extends object>(object: O): object | null;
+
+declare const x: typeof getProto | null;
+
+export = x;
diff --git a/server/node_modules/get-proto/index.js b/server/node_modules/get-proto/index.js
new file mode 100644
index 0000000..7e5747b
--- /dev/null
+++ b/server/node_modules/get-proto/index.js
@@ -0,0 +1,27 @@
+'use strict';
+
+var reflectGetProto = require('./Reflect.getPrototypeOf');
+var originalGetProto = require('./Object.getPrototypeOf');
+
+var getDunderProto = require('dunder-proto/get');
+
+/** @type {import('.')} */
+module.exports = reflectGetProto
+	? function getProto(O) {
+		// @ts-expect-error TS can't narrow inside a closure, for some reason
+		return reflectGetProto(O);
+	}
+	: originalGetProto
+		? function getProto(O) {
+			if (!O || (typeof O !== 'object' && typeof O !== 'function')) {
+				throw new TypeError('getProto: not an object');
+			}
+			// @ts-expect-error TS can't narrow inside a closure, for some reason
+			return originalGetProto(O);
+		}
+		: getDunderProto
+			? function getProto(O) {
+				// @ts-expect-error TS can't narrow inside a closure, for some reason
+				return getDunderProto(O);
+			}
+			: null;
diff --git a/server/node_modules/get-proto/package.json b/server/node_modules/get-proto/package.json
new file mode 100644
index 0000000..9c35cec
--- /dev/null
+++ b/server/node_modules/get-proto/package.json
@@ -0,0 +1,81 @@
+{
+	"name": "get-proto",
+	"version": "1.0.1",
+	"description": "Robustly get the [[Prototype]] of an object",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./Reflect.getPrototypeOf": "./Reflect.getPrototypeOf.js",
+		"./Object.getPrototypeOf": "./Object.getPrototypeOf.js",
+		"./package.json": "./package.json"
+	},
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prepublishOnly": "safe-publish-latest",
+		"pretest": "npm run --silent lint",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@\">=10.2\" audit --production",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc && attw -P",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/get-proto.git"
+	},
+	"keywords": [
+		"get",
+		"proto",
+		"prototype",
+		"getPrototypeOf",
+		"[[Prototype]]"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/get-proto/issues"
+	},
+	"homepage": "https://github.com/ljharb/get-proto#readme",
+	"dependencies": {
+		"dunder-proto": "^1.0.1",
+		"es-object-atoms": "^1.0.0"
+	},
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.2",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.3",
+		"@types/tape": "^5.8.0",
+		"auto-changelog": "^2.5.0",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"engines": {
+		"node": ">= 0.4"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"testling": {
+		"files": "test/index.js"
+	}
+}
diff --git a/server/node_modules/get-proto/test/index.js b/server/node_modules/get-proto/test/index.js
new file mode 100644
index 0000000..5a2ece2
--- /dev/null
+++ b/server/node_modules/get-proto/test/index.js
@@ -0,0 +1,68 @@
+'use strict';
+
+var test = require('tape');
+
+var getProto = require('../');
+
+test('getProto', function (t) {
+	t.equal(typeof getProto, 'function', 'is a function');
+
+	t.test('can get', { skip: !getProto }, function (st) {
+		if (getProto) { // TS doesn't understand tape's skip
+			var proto = { b: 2 };
+			st.equal(getProto(proto), Object.prototype, 'proto: returns the [[Prototype]]');
+
+			st.test('nullish value', function (s2t) {
+			// @ts-expect-error
+				s2t['throws'](function () { return getProto(undefined); }, TypeError, 'undefined is not an object');
+				// @ts-expect-error
+				s2t['throws'](function () { return getProto(null); }, TypeError, 'null is not an object');
+				s2t.end();
+			});
+
+			// @ts-expect-error
+			st['throws'](function () { getProto(true); }, 'throws for true');
+			// @ts-expect-error
+			st['throws'](function () { getProto(false); }, 'throws for false');
+			// @ts-expect-error
+			st['throws'](function () { getProto(42); }, 'throws for 42');
+			// @ts-expect-error
+			st['throws'](function () { getProto(NaN); }, 'throws for NaN');
+			// @ts-expect-error
+			st['throws'](function () { getProto(0); }, 'throws for +0');
+			// @ts-expect-error
+			st['throws'](function () { getProto(-0); }, 'throws for -0');
+			// @ts-expect-error
+			st['throws'](function () { getProto(Infinity); }, 'throws for ∞');
+			// @ts-expect-error
+			st['throws'](function () { getProto(-Infinity); }, 'throws for -∞');
+			// @ts-expect-error
+			st['throws'](function () { getProto(''); }, 'throws for empty string');
+			// @ts-expect-error
+			st['throws'](function () { getProto('foo'); }, 'throws for non-empty string');
+			st.equal(getProto(/a/g), RegExp.prototype);
+			st.equal(getProto(new Date()), Date.prototype);
+			st.equal(getProto(function () {}), Function.prototype);
+			st.equal(getProto([]), Array.prototype);
+			st.equal(getProto({}), Object.prototype);
+
+			var nullObject = { __proto__: null };
+			if ('toString' in nullObject) {
+				st.comment('no null objects in this engine');
+				st.equal(getProto(nullObject), Object.prototype, '"null" object has Object.prototype as [[Prototype]]');
+			} else {
+				st.equal(getProto(nullObject), null, 'null object has null [[Prototype]]');
+			}
+		}
+
+		st.end();
+	});
+
+	t.test('can not get', { skip: !!getProto }, function (st) {
+		st.equal(getProto, null);
+
+		st.end();
+	});
+
+	t.end();
+});
diff --git a/server/node_modules/get-proto/tsconfig.json b/server/node_modules/get-proto/tsconfig.json
new file mode 100644
index 0000000..60fb90e
--- /dev/null
+++ b/server/node_modules/get-proto/tsconfig.json
@@ -0,0 +1,9 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		//"target": "es2021",
+	},
+	"exclude": [
+		"coverage",
+	],
+}
diff --git a/server/node_modules/github-from-package/.travis.yml b/server/node_modules/github-from-package/.travis.yml
new file mode 100644
index 0000000..895dbd3
--- /dev/null
+++ b/server/node_modules/github-from-package/.travis.yml
@@ -0,0 +1,4 @@
+language: node_js
+node_js:
+  - 0.6
+  - 0.8
diff --git a/server/node_modules/github-from-package/LICENSE b/server/node_modules/github-from-package/LICENSE
new file mode 100644
index 0000000..ee27ba4
--- /dev/null
+++ b/server/node_modules/github-from-package/LICENSE
@@ -0,0 +1,18 @@
+This software is released under the MIT license:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/github-from-package/example/package.json b/server/node_modules/github-from-package/example/package.json
new file mode 100644
index 0000000..03494f4
--- /dev/null
+++ b/server/node_modules/github-from-package/example/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "beep-boop",
+  "version": "1.2.3",
+  "repository" : {
+    "type" : "git",
+    "url": "git@github.com:substack/beep-boop.git"
+  }
+}
diff --git a/server/node_modules/github-from-package/example/url.js b/server/node_modules/github-from-package/example/url.js
new file mode 100644
index 0000000..138fb8a
--- /dev/null
+++ b/server/node_modules/github-from-package/example/url.js
@@ -0,0 +1,3 @@
+var github = require('../');
+var url = github(require('./package.json'));
+console.log(url);
diff --git a/server/node_modules/github-from-package/index.js b/server/node_modules/github-from-package/index.js
new file mode 100644
index 0000000..3d1d657
--- /dev/null
+++ b/server/node_modules/github-from-package/index.js
@@ -0,0 +1,17 @@
+module.exports = function (pkg) {
+    var m;
+    if (m = match(JSON.stringify(pkg.repository))) {
+        return m;
+    }
+    else if (m = match(JSON.stringify(pkg))) {
+        return m;
+    }
+    return undefined;
+};
+
+function match (str) {
+    var m = /\bgithub.com[:\/]([^\/"]+)\/([^\/"]+)/.exec(str);
+    if (m) {
+        return 'https://github.com/' + m[1] + '/' + m[2].replace(/\.git$/, '');
+    }
+}
diff --git a/server/node_modules/github-from-package/package.json b/server/node_modules/github-from-package/package.json
new file mode 100644
index 0000000..a3e240f
--- /dev/null
+++ b/server/node_modules/github-from-package/package.json
@@ -0,0 +1,30 @@
+{
+    "name" : "github-from-package",
+    "version" : "0.0.0",
+    "description" : "return the github url from a package.json file",
+    "main" : "index.js",
+    "devDependencies" : {
+        "tap" : "~0.3.0",
+        "tape" : "~0.1.5"
+    },
+    "scripts" : {
+        "test" : "tap test/*.js"
+    },
+    "repository" : {
+        "type" : "git",
+        "url" : "git://github.com/substack/github-from-package.git"
+    },
+    "homepage" : "https://github.com/substack/github-from-package",
+    "keywords" : [
+        "github",
+        "package.json",
+        "npm",
+        "repository"
+    ],
+    "author" : {
+        "name" : "James Halliday",
+        "email" : "mail@substack.net",
+        "url" : "http://substack.net"
+    },
+    "license" : "MIT"
+}
diff --git a/server/node_modules/github-from-package/readme.markdown b/server/node_modules/github-from-package/readme.markdown
new file mode 100644
index 0000000..5ba397d
--- /dev/null
+++ b/server/node_modules/github-from-package/readme.markdown
@@ -0,0 +1,53 @@
+# github-from-package
+
+return the github url from a package.json file
+
+[![build status](https://secure.travis-ci.org/substack/github-from-package.png)](http://travis-ci.org/substack/github-from-package)
+
+# example
+
+For the `./package.json` file:
+
+``` json
+{
+  "name": "beep-boop",
+  "version": "1.2.3",
+  "repository" : {
+    "type" : "git",
+    "url": "git@github.com:substack/beep-boop.git"
+  }
+}
+```
+
+``` js
+var github = require('github-from-package');
+var url = github(require('./package.json'));
+console.log(url);
+```
+
+```
+https://github.com/substack/beep-boop
+```
+
+# methods
+
+``` js
+var github = require('github-from-package')
+```
+
+## var url = github(pkg)
+
+Return the most likely github url from the package.json contents `pkg`. If no
+github url can be determined, return `undefined`.
+
+# install
+
+With [npm](https://npmjs.org) do:
+
+```
+npm install github-from-package
+```
+
+# license
+
+MIT
diff --git a/server/node_modules/github-from-package/test/a.json b/server/node_modules/github-from-package/test/a.json
new file mode 100644
index 0000000..03494f4
--- /dev/null
+++ b/server/node_modules/github-from-package/test/a.json
@@ -0,0 +1,8 @@
+{
+  "name": "beep-boop",
+  "version": "1.2.3",
+  "repository" : {
+    "type" : "git",
+    "url": "git@github.com:substack/beep-boop.git"
+  }
+}
diff --git a/server/node_modules/github-from-package/test/b.json b/server/node_modules/github-from-package/test/b.json
new file mode 100644
index 0000000..0209325
--- /dev/null
+++ b/server/node_modules/github-from-package/test/b.json
@@ -0,0 +1,5 @@
+{
+  "name": "beep-boop",
+  "version": "1.2.3",
+  "repository" : "git@github.com:substack/beep-boop.git"
+}
diff --git a/server/node_modules/github-from-package/test/c.json b/server/node_modules/github-from-package/test/c.json
new file mode 100644
index 0000000..65f6dda
--- /dev/null
+++ b/server/node_modules/github-from-package/test/c.json
@@ -0,0 +1,5 @@
+{
+  "name": "beep-boop",
+  "version": "1.2.3",
+  "repository" : "https://github.com/substack/beep-boop.git"
+}
diff --git a/server/node_modules/github-from-package/test/d.json b/server/node_modules/github-from-package/test/d.json
new file mode 100644
index 0000000..c61f3cd
--- /dev/null
+++ b/server/node_modules/github-from-package/test/d.json
@@ -0,0 +1,7 @@
+{
+  "name": "beep-boop",
+  "version": "1.2.3",
+  "repository" : {
+    "url": "https://github.com/substack/beep-boop"
+  }
+}
diff --git a/server/node_modules/github-from-package/test/e.json b/server/node_modules/github-from-package/test/e.json
new file mode 100644
index 0000000..770b438
--- /dev/null
+++ b/server/node_modules/github-from-package/test/e.json
@@ -0,0 +1,5 @@
+{
+  "name": "beep-boop",
+  "version": "1.2.3",
+  "homepage": "https://github.com/substack/beep-boop/issues"
+}
diff --git a/server/node_modules/github-from-package/test/url.js b/server/node_modules/github-from-package/test/url.js
new file mode 100644
index 0000000..d5a0a66
--- /dev/null
+++ b/server/node_modules/github-from-package/test/url.js
@@ -0,0 +1,19 @@
+var test = require('tape');
+var github = require('../');
+var packages = {
+    a : require('./a.json'),
+    b : require('./b.json'),
+    c : require('./c.json'),
+    d : require('./d.json'),
+    e : require('./e.json')
+};
+
+test(function (t) {
+    t.plan(5);
+    var url = 'https://github.com/substack/beep-boop';
+    t.equal(url, github(packages.a), 'a.json comparison');
+    t.equal(url, github(packages.b), 'b.json comparison');
+    t.equal(url, github(packages.c), 'c.json comparison');
+    t.equal(url, github(packages.d), 'd.json comparison');
+    t.equal(url, github(packages.e), 'e.json comparison');
+});
diff --git a/server/node_modules/glob/LICENSE b/server/node_modules/glob/LICENSE
new file mode 100644
index 0000000..42ca266
--- /dev/null
+++ b/server/node_modules/glob/LICENSE
@@ -0,0 +1,21 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+## Glob Logo
+
+Glob's logo created by Tanya Brassie <http://tanyabrassie.com/>, licensed
+under a Creative Commons Attribution-ShareAlike 4.0 International License
+https://creativecommons.org/licenses/by-sa/4.0/
diff --git a/server/node_modules/glob/README.md b/server/node_modules/glob/README.md
new file mode 100644
index 0000000..83f0c83
--- /dev/null
+++ b/server/node_modules/glob/README.md
@@ -0,0 +1,378 @@
+# Glob
+
+Match files using the patterns the shell uses, like stars and stuff.
+
+[![Build Status](https://travis-ci.org/isaacs/node-glob.svg?branch=master)](https://travis-ci.org/isaacs/node-glob/) [![Build Status](https://ci.appveyor.com/api/projects/status/kd7f3yftf7unxlsx?svg=true)](https://ci.appveyor.com/project/isaacs/node-glob) [![Coverage Status](https://coveralls.io/repos/isaacs/node-glob/badge.svg?branch=master&service=github)](https://coveralls.io/github/isaacs/node-glob?branch=master)
+
+This is a glob implementation in JavaScript.  It uses the `minimatch`
+library to do its matching.
+
+![a fun cartoon logo made of glob characters](logo/glob.png)
+
+## Usage
+
+Install with npm
+
+```
+npm i glob
+```
+
+```javascript
+var glob = require("glob")
+
+// options is optional
+glob("**/*.js", options, function (er, files) {
+  // files is an array of filenames.
+  // If the `nonull` option is set, and nothing
+  // was found, then files is ["**/*.js"]
+  // er is an error object or null.
+})
+```
+
+## Glob Primer
+
+"Globs" are the patterns you type when you do stuff like `ls *.js` on
+the command line, or put `build/*` in a `.gitignore` file.
+
+Before parsing the path part patterns, braced sections are expanded
+into a set.  Braced sections start with `{` and end with `}`, with any
+number of comma-delimited sections within.  Braced sections may contain
+slash characters, so `a{/b/c,bcd}` would expand into `a/b/c` and `abcd`.
+
+The following characters have special magic meaning when used in a
+path portion:
+
+* `*` Matches 0 or more characters in a single path portion
+* `?` Matches 1 character
+* `[...]` Matches a range of characters, similar to a RegExp range.
+  If the first character of the range is `!` or `^` then it matches
+  any character not in the range.
+* `!(pattern|pattern|pattern)` Matches anything that does not match
+  any of the patterns provided.
+* `?(pattern|pattern|pattern)` Matches zero or one occurrence of the
+  patterns provided.
+* `+(pattern|pattern|pattern)` Matches one or more occurrences of the
+  patterns provided.
+* `*(a|b|c)` Matches zero or more occurrences of the patterns provided
+* `@(pattern|pat*|pat?erN)` Matches exactly one of the patterns
+  provided
+* `**` If a "globstar" is alone in a path portion, then it matches
+  zero or more directories and subdirectories searching for matches.
+  It does not crawl symlinked directories.
+
+### Dots
+
+If a file or directory path portion has a `.` as the first character,
+then it will not match any glob pattern unless that pattern's
+corresponding path part also has a `.` as its first character.
+
+For example, the pattern `a/.*/c` would match the file at `a/.b/c`.
+However the pattern `a/*/c` would not, because `*` does not start with
+a dot character.
+
+You can make glob treat dots as normal characters by setting
+`dot:true` in the options.
+
+### Basename Matching
+
+If you set `matchBase:true` in the options, and the pattern has no
+slashes in it, then it will seek for any file anywhere in the tree
+with a matching basename.  For example, `*.js` would match
+`test/simple/basic.js`.
+
+### Empty Sets
+
+If no matching files are found, then an empty array is returned.  This
+differs from the shell, where the pattern itself is returned.  For
+example:
+
+    $ echo a*s*d*f
+    a*s*d*f
+
+To get the bash-style behavior, set the `nonull:true` in the options.
+
+### See Also:
+
+* `man sh`
+* `man bash` (Search for "Pattern Matching")
+* `man 3 fnmatch`
+* `man 5 gitignore`
+* [minimatch documentation](https://github.com/isaacs/minimatch)
+
+## glob.hasMagic(pattern, [options])
+
+Returns `true` if there are any special characters in the pattern, and
+`false` otherwise.
+
+Note that the options affect the results.  If `noext:true` is set in
+the options object, then `+(a|b)` will not be considered a magic
+pattern.  If the pattern has a brace expansion, like `a/{b/c,x/y}`
+then that is considered magical, unless `nobrace:true` is set in the
+options.
+
+## glob(pattern, [options], cb)
+
+* `pattern` `{String}` Pattern to be matched
+* `options` `{Object}`
+* `cb` `{Function}`
+  * `err` `{Error | null}`
+  * `matches` `{Array<String>}` filenames found matching the pattern
+
+Perform an asynchronous glob search.
+
+## glob.sync(pattern, [options])
+
+* `pattern` `{String}` Pattern to be matched
+* `options` `{Object}`
+* return: `{Array<String>}` filenames found matching the pattern
+
+Perform a synchronous glob search.
+
+## Class: glob.Glob
+
+Create a Glob object by instantiating the `glob.Glob` class.
+
+```javascript
+var Glob = require("glob").Glob
+var mg = new Glob(pattern, options, cb)
+```
+
+It's an EventEmitter, and starts walking the filesystem to find matches
+immediately.
+
+### new glob.Glob(pattern, [options], [cb])
+
+* `pattern` `{String}` pattern to search for
+* `options` `{Object}`
+* `cb` `{Function}` Called when an error occurs, or matches are found
+  * `err` `{Error | null}`
+  * `matches` `{Array<String>}` filenames found matching the pattern
+
+Note that if the `sync` flag is set in the options, then matches will
+be immediately available on the `g.found` member.
+
+### Properties
+
+* `minimatch` The minimatch object that the glob uses.
+* `options` The options object passed in.
+* `aborted` Boolean which is set to true when calling `abort()`.  There
+  is no way at this time to continue a glob search after aborting, but
+  you can re-use the statCache to avoid having to duplicate syscalls.
+* `cache` Convenience object.  Each field has the following possible
+  values:
+  * `false` - Path does not exist
+  * `true` - Path exists
+  * `'FILE'` - Path exists, and is not a directory
+  * `'DIR'` - Path exists, and is a directory
+  * `[file, entries, ...]` - Path exists, is a directory, and the
+    array value is the results of `fs.readdir`
+* `statCache` Cache of `fs.stat` results, to prevent statting the same
+  path multiple times.
+* `symlinks` A record of which paths are symbolic links, which is
+  relevant in resolving `**` patterns.
+* `realpathCache` An optional object which is passed to `fs.realpath`
+  to minimize unnecessary syscalls.  It is stored on the instantiated
+  Glob object, and may be re-used.
+
+### Events
+
+* `end` When the matching is finished, this is emitted with all the
+  matches found.  If the `nonull` option is set, and no match was found,
+  then the `matches` list contains the original pattern.  The matches
+  are sorted, unless the `nosort` flag is set.
+* `match` Every time a match is found, this is emitted with the specific
+  thing that matched. It is not deduplicated or resolved to a realpath.
+* `error` Emitted when an unexpected error is encountered, or whenever
+  any fs error occurs if `options.strict` is set.
+* `abort` When `abort()` is called, this event is raised.
+
+### Methods
+
+* `pause` Temporarily stop the search
+* `resume` Resume the search
+* `abort` Stop the search forever
+
+### Options
+
+All the options that can be passed to Minimatch can also be passed to
+Glob to change pattern matching behavior.  Also, some have been added,
+or have glob-specific ramifications.
+
+All options are false by default, unless otherwise noted.
+
+All options are added to the Glob object, as well.
+
+If you are running many `glob` operations, you can pass a Glob object
+as the `options` argument to a subsequent operation to shortcut some
+`stat` and `readdir` calls.  At the very least, you may pass in shared
+`symlinks`, `statCache`, `realpathCache`, and `cache` options, so that
+parallel glob operations will be sped up by sharing information about
+the filesystem.
+
+* `cwd` The current working directory in which to search.  Defaults
+  to `process.cwd()`.
+* `root` The place where patterns starting with `/` will be mounted
+  onto.  Defaults to `path.resolve(options.cwd, "/")` (`/` on Unix
+  systems, and `C:\` or some such on Windows.)
+* `dot` Include `.dot` files in normal matches and `globstar` matches.
+  Note that an explicit dot in a portion of the pattern will always
+  match dot files.
+* `nomount` By default, a pattern starting with a forward-slash will be
+  "mounted" onto the root setting, so that a valid filesystem path is
+  returned.  Set this flag to disable that behavior.
+* `mark` Add a `/` character to directory matches.  Note that this
+  requires additional stat calls.
+* `nosort` Don't sort the results.
+* `stat` Set to true to stat *all* results.  This reduces performance
+  somewhat, and is completely unnecessary, unless `readdir` is presumed
+  to be an untrustworthy indicator of file existence.
+* `silent` When an unusual error is encountered when attempting to
+  read a directory, a warning will be printed to stderr.  Set the
+  `silent` option to true to suppress these warnings.
+* `strict` When an unusual error is encountered when attempting to
+  read a directory, the process will just continue on in search of
+  other matches.  Set the `strict` option to raise an error in these
+  cases.
+* `cache` See `cache` property above.  Pass in a previously generated
+  cache object to save some fs calls.
+* `statCache` A cache of results of filesystem information, to prevent
+  unnecessary stat calls.  While it should not normally be necessary
+  to set this, you may pass the statCache from one glob() call to the
+  options object of another, if you know that the filesystem will not
+  change between calls.  (See "Race Conditions" below.)
+* `symlinks` A cache of known symbolic links.  You may pass in a
+  previously generated `symlinks` object to save `lstat` calls when
+  resolving `**` matches.
+* `sync` DEPRECATED: use `glob.sync(pattern, opts)` instead.
+* `nounique` In some cases, brace-expanded patterns can result in the
+  same file showing up multiple times in the result set.  By default,
+  this implementation prevents duplicates in the result set.  Set this
+  flag to disable that behavior.
+* `nonull` Set to never return an empty set, instead returning a set
+  containing the pattern itself.  This is the default in glob(3).
+* `debug` Set to enable debug logging in minimatch and glob.
+* `nobrace` Do not expand `{a,b}` and `{1..3}` brace sets.
+* `noglobstar` Do not match `**` against multiple filenames.  (Ie,
+  treat it as a normal `*` instead.)
+* `noext` Do not match `+(a|b)` "extglob" patterns.
+* `nocase` Perform a case-insensitive match.  Note: on
+  case-insensitive filesystems, non-magic patterns will match by
+  default, since `stat` and `readdir` will not raise errors.
+* `matchBase` Perform a basename-only match if the pattern does not
+  contain any slash characters.  That is, `*.js` would be treated as
+  equivalent to `**/*.js`, matching all js files in all directories.
+* `nodir` Do not match directories, only files.  (Note: to match
+  *only* directories, simply put a `/` at the end of the pattern.)
+* `ignore` Add a pattern or an array of glob patterns to exclude matches.
+  Note: `ignore` patterns are *always* in `dot:true` mode, regardless
+  of any other settings.
+* `follow` Follow symlinked directories when expanding `**` patterns.
+  Note that this can result in a lot of duplicate references in the
+  presence of cyclic links.
+* `realpath` Set to true to call `fs.realpath` on all of the results.
+  In the case of a symlink that cannot be resolved, the full absolute
+  path to the matched entry is returned (though it will usually be a
+  broken symlink)
+* `absolute` Set to true to always receive absolute paths for matched
+  files.  Unlike `realpath`, this also affects the values returned in
+  the `match` event.
+* `fs` File-system object with Node's `fs` API. By default, the built-in
+  `fs` module will be used. Set to a volume provided by a library like
+  `memfs` to avoid using the "real" file-system.
+
+## Comparisons to other fnmatch/glob implementations
+
+While strict compliance with the existing standards is a worthwhile
+goal, some discrepancies exist between node-glob and other
+implementations, and are intentional.
+
+The double-star character `**` is supported by default, unless the
+`noglobstar` flag is set.  This is supported in the manner of bsdglob
+and bash 4.3, where `**` only has special significance if it is the only
+thing in a path part.  That is, `a/**/b` will match `a/x/y/b`, but
+`a/**b` will not.
+
+Note that symlinked directories are not crawled as part of a `**`,
+though their contents may match against subsequent portions of the
+pattern.  This prevents infinite loops and duplicates and the like.
+
+If an escaped pattern has no matches, and the `nonull` flag is set,
+then glob returns the pattern as-provided, rather than
+interpreting the character escapes.  For example,
+`glob.match([], "\\*a\\?")` will return `"\\*a\\?"` rather than
+`"*a?"`.  This is akin to setting the `nullglob` option in bash, except
+that it does not resolve escaped pattern characters.
+
+If brace expansion is not disabled, then it is performed before any
+other interpretation of the glob pattern.  Thus, a pattern like
+`+(a|{b),c)}`, which would not be valid in bash or zsh, is expanded
+**first** into the set of `+(a|b)` and `+(a|c)`, and those patterns are
+checked for validity.  Since those two are valid, matching proceeds.
+
+### Comments and Negation
+
+Previously, this module let you mark a pattern as a "comment" if it
+started with a `#` character, or a "negated" pattern if it started
+with a `!` character.
+
+These options were deprecated in version 5, and removed in version 6.
+
+To specify things that should not match, use the `ignore` option.
+
+## Windows
+
+**Please only use forward-slashes in glob expressions.**
+
+Though windows uses either `/` or `\` as its path separator, only `/`
+characters are used by this glob implementation.  You must use
+forward-slashes **only** in glob expressions.  Back-slashes will always
+be interpreted as escape characters, not path separators.
+
+Results from absolute patterns such as `/foo/*` are mounted onto the
+root setting using `path.join`.  On windows, this will by default result
+in `/foo/*` matching `C:\foo\bar.txt`.
+
+## Race Conditions
+
+Glob searching, by its very nature, is susceptible to race conditions,
+since it relies on directory walking and such.
+
+As a result, it is possible that a file that exists when glob looks for
+it may have been deleted or modified by the time it returns the result.
+
+As part of its internal implementation, this program caches all stat
+and readdir calls that it makes, in order to cut down on system
+overhead.  However, this also makes it even more susceptible to races,
+especially if the cache or statCache objects are reused between glob
+calls.
+
+Users are thus advised not to use a glob result as a guarantee of
+filesystem state in the face of rapid changes.  For the vast majority
+of operations, this is never a problem.
+
+## Glob Logo
+Glob's logo was created by [Tanya Brassie](http://tanyabrassie.com/). Logo files can be found [here](https://github.com/isaacs/node-glob/tree/master/logo).
+
+The logo is licensed under a [Creative Commons Attribution-ShareAlike 4.0 International License](https://creativecommons.org/licenses/by-sa/4.0/).
+
+## Contributing
+
+Any change to behavior (including bugfixes) must come with a test.
+
+Patches that fail tests or reduce performance will be rejected.
+
+```
+# to run tests
+npm test
+
+# to re-generate test fixtures
+npm run test-regen
+
+# to benchmark against bash/zsh
+npm run bench
+
+# to profile javascript
+npm run prof
+```
+
+![](oh-my-glob.gif)
diff --git a/server/node_modules/glob/common.js b/server/node_modules/glob/common.js
new file mode 100644
index 0000000..424c46e
--- /dev/null
+++ b/server/node_modules/glob/common.js
@@ -0,0 +1,238 @@
+exports.setopts = setopts
+exports.ownProp = ownProp
+exports.makeAbs = makeAbs
+exports.finish = finish
+exports.mark = mark
+exports.isIgnored = isIgnored
+exports.childrenIgnored = childrenIgnored
+
+function ownProp (obj, field) {
+  return Object.prototype.hasOwnProperty.call(obj, field)
+}
+
+var fs = require("fs")
+var path = require("path")
+var minimatch = require("minimatch")
+var isAbsolute = require("path-is-absolute")
+var Minimatch = minimatch.Minimatch
+
+function alphasort (a, b) {
+  return a.localeCompare(b, 'en')
+}
+
+function setupIgnores (self, options) {
+  self.ignore = options.ignore || []
+
+  if (!Array.isArray(self.ignore))
+    self.ignore = [self.ignore]
+
+  if (self.ignore.length) {
+    self.ignore = self.ignore.map(ignoreMap)
+  }
+}
+
+// ignore patterns are always in dot:true mode.
+function ignoreMap (pattern) {
+  var gmatcher = null
+  if (pattern.slice(-3) === '/**') {
+    var gpattern = pattern.replace(/(\/\*\*)+$/, '')
+    gmatcher = new Minimatch(gpattern, { dot: true })
+  }
+
+  return {
+    matcher: new Minimatch(pattern, { dot: true }),
+    gmatcher: gmatcher
+  }
+}
+
+function setopts (self, pattern, options) {
+  if (!options)
+    options = {}
+
+  // base-matching: just use globstar for that.
+  if (options.matchBase && -1 === pattern.indexOf("/")) {
+    if (options.noglobstar) {
+      throw new Error("base matching requires globstar")
+    }
+    pattern = "**/" + pattern
+  }
+
+  self.silent = !!options.silent
+  self.pattern = pattern
+  self.strict = options.strict !== false
+  self.realpath = !!options.realpath
+  self.realpathCache = options.realpathCache || Object.create(null)
+  self.follow = !!options.follow
+  self.dot = !!options.dot
+  self.mark = !!options.mark
+  self.nodir = !!options.nodir
+  if (self.nodir)
+    self.mark = true
+  self.sync = !!options.sync
+  self.nounique = !!options.nounique
+  self.nonull = !!options.nonull
+  self.nosort = !!options.nosort
+  self.nocase = !!options.nocase
+  self.stat = !!options.stat
+  self.noprocess = !!options.noprocess
+  self.absolute = !!options.absolute
+  self.fs = options.fs || fs
+
+  self.maxLength = options.maxLength || Infinity
+  self.cache = options.cache || Object.create(null)
+  self.statCache = options.statCache || Object.create(null)
+  self.symlinks = options.symlinks || Object.create(null)
+
+  setupIgnores(self, options)
+
+  self.changedCwd = false
+  var cwd = process.cwd()
+  if (!ownProp(options, "cwd"))
+    self.cwd = cwd
+  else {
+    self.cwd = path.resolve(options.cwd)
+    self.changedCwd = self.cwd !== cwd
+  }
+
+  self.root = options.root || path.resolve(self.cwd, "/")
+  self.root = path.resolve(self.root)
+  if (process.platform === "win32")
+    self.root = self.root.replace(/\\/g, "/")
+
+  // TODO: is an absolute `cwd` supposed to be resolved against `root`?
+  // e.g. { cwd: '/test', root: __dirname } === path.join(__dirname, '/test')
+  self.cwdAbs = isAbsolute(self.cwd) ? self.cwd : makeAbs(self, self.cwd)
+  if (process.platform === "win32")
+    self.cwdAbs = self.cwdAbs.replace(/\\/g, "/")
+  self.nomount = !!options.nomount
+
+  // disable comments and negation in Minimatch.
+  // Note that they are not supported in Glob itself anyway.
+  options.nonegate = true
+  options.nocomment = true
+  // always treat \ in patterns as escapes, not path separators
+  options.allowWindowsEscape = false
+
+  self.minimatch = new Minimatch(pattern, options)
+  self.options = self.minimatch.options
+}
+
+function finish (self) {
+  var nou = self.nounique
+  var all = nou ? [] : Object.create(null)
+
+  for (var i = 0, l = self.matches.length; i < l; i ++) {
+    var matches = self.matches[i]
+    if (!matches || Object.keys(matches).length === 0) {
+      if (self.nonull) {
+        // do like the shell, and spit out the literal glob
+        var literal = self.minimatch.globSet[i]
+        if (nou)
+          all.push(literal)
+        else
+          all[literal] = true
+      }
+    } else {
+      // had matches
+      var m = Object.keys(matches)
+      if (nou)
+        all.push.apply(all, m)
+      else
+        m.forEach(function (m) {
+          all[m] = true
+        })
+    }
+  }
+
+  if (!nou)
+    all = Object.keys(all)
+
+  if (!self.nosort)
+    all = all.sort(alphasort)
+
+  // at *some* point we statted all of these
+  if (self.mark) {
+    for (var i = 0; i < all.length; i++) {
+      all[i] = self._mark(all[i])
+    }
+    if (self.nodir) {
+      all = all.filter(function (e) {
+        var notDir = !(/\/$/.test(e))
+        var c = self.cache[e] || self.cache[makeAbs(self, e)]
+        if (notDir && c)
+          notDir = c !== 'DIR' && !Array.isArray(c)
+        return notDir
+      })
+    }
+  }
+
+  if (self.ignore.length)
+    all = all.filter(function(m) {
+      return !isIgnored(self, m)
+    })
+
+  self.found = all
+}
+
+function mark (self, p) {
+  var abs = makeAbs(self, p)
+  var c = self.cache[abs]
+  var m = p
+  if (c) {
+    var isDir = c === 'DIR' || Array.isArray(c)
+    var slash = p.slice(-1) === '/'
+
+    if (isDir && !slash)
+      m += '/'
+    else if (!isDir && slash)
+      m = m.slice(0, -1)
+
+    if (m !== p) {
+      var mabs = makeAbs(self, m)
+      self.statCache[mabs] = self.statCache[abs]
+      self.cache[mabs] = self.cache[abs]
+    }
+  }
+
+  return m
+}
+
+// lotta situps...
+function makeAbs (self, f) {
+  var abs = f
+  if (f.charAt(0) === '/') {
+    abs = path.join(self.root, f)
+  } else if (isAbsolute(f) || f === '') {
+    abs = f
+  } else if (self.changedCwd) {
+    abs = path.resolve(self.cwd, f)
+  } else {
+    abs = path.resolve(f)
+  }
+
+  if (process.platform === 'win32')
+    abs = abs.replace(/\\/g, '/')
+
+  return abs
+}
+
+
+// Return true, if pattern ends with globstar '**', for the accompanying parent directory.
+// Ex:- If node_modules/** is the pattern, add 'node_modules' to ignore list along with it's contents
+function isIgnored (self, path) {
+  if (!self.ignore.length)
+    return false
+
+  return self.ignore.some(function(item) {
+    return item.matcher.match(path) || !!(item.gmatcher && item.gmatcher.match(path))
+  })
+}
+
+function childrenIgnored (self, path) {
+  if (!self.ignore.length)
+    return false
+
+  return self.ignore.some(function(item) {
+    return !!(item.gmatcher && item.gmatcher.match(path))
+  })
+}
diff --git a/server/node_modules/glob/glob.js b/server/node_modules/glob/glob.js
new file mode 100644
index 0000000..37a4d7e
--- /dev/null
+++ b/server/node_modules/glob/glob.js
@@ -0,0 +1,790 @@
+// Approach:
+//
+// 1. Get the minimatch set
+// 2. For each pattern in the set, PROCESS(pattern, false)
+// 3. Store matches per-set, then uniq them
+//
+// PROCESS(pattern, inGlobStar)
+// Get the first [n] items from pattern that are all strings
+// Join these together.  This is PREFIX.
+//   If there is no more remaining, then stat(PREFIX) and
+//   add to matches if it succeeds.  END.
+//
+// If inGlobStar and PREFIX is symlink and points to dir
+//   set ENTRIES = []
+// else readdir(PREFIX) as ENTRIES
+//   If fail, END
+//
+// with ENTRIES
+//   If pattern[n] is GLOBSTAR
+//     // handle the case where the globstar match is empty
+//     // by pruning it out, and testing the resulting pattern
+//     PROCESS(pattern[0..n] + pattern[n+1 .. $], false)
+//     // handle other cases.
+//     for ENTRY in ENTRIES (not dotfiles)
+//       // attach globstar + tail onto the entry
+//       // Mark that this entry is a globstar match
+//       PROCESS(pattern[0..n] + ENTRY + pattern[n .. $], true)
+//
+//   else // not globstar
+//     for ENTRY in ENTRIES (not dotfiles, unless pattern[n] is dot)
+//       Test ENTRY against pattern[n]
+//       If fails, continue
+//       If passes, PROCESS(pattern[0..n] + item + pattern[n+1 .. $])
+//
+// Caveat:
+//   Cache all stats and readdirs results to minimize syscall.  Since all
+//   we ever care about is existence and directory-ness, we can just keep
+//   `true` for files, and [children,...] for directories, or `false` for
+//   things that don't exist.
+
+module.exports = glob
+
+var rp = require('fs.realpath')
+var minimatch = require('minimatch')
+var Minimatch = minimatch.Minimatch
+var inherits = require('inherits')
+var EE = require('events').EventEmitter
+var path = require('path')
+var assert = require('assert')
+var isAbsolute = require('path-is-absolute')
+var globSync = require('./sync.js')
+var common = require('./common.js')
+var setopts = common.setopts
+var ownProp = common.ownProp
+var inflight = require('inflight')
+var util = require('util')
+var childrenIgnored = common.childrenIgnored
+var isIgnored = common.isIgnored
+
+var once = require('once')
+
+function glob (pattern, options, cb) {
+  if (typeof options === 'function') cb = options, options = {}
+  if (!options) options = {}
+
+  if (options.sync) {
+    if (cb)
+      throw new TypeError('callback provided to sync glob')
+    return globSync(pattern, options)
+  }
+
+  return new Glob(pattern, options, cb)
+}
+
+glob.sync = globSync
+var GlobSync = glob.GlobSync = globSync.GlobSync
+
+// old api surface
+glob.glob = glob
+
+function extend (origin, add) {
+  if (add === null || typeof add !== 'object') {
+    return origin
+  }
+
+  var keys = Object.keys(add)
+  var i = keys.length
+  while (i--) {
+    origin[keys[i]] = add[keys[i]]
+  }
+  return origin
+}
+
+glob.hasMagic = function (pattern, options_) {
+  var options = extend({}, options_)
+  options.noprocess = true
+
+  var g = new Glob(pattern, options)
+  var set = g.minimatch.set
+
+  if (!pattern)
+    return false
+
+  if (set.length > 1)
+    return true
+
+  for (var j = 0; j < set[0].length; j++) {
+    if (typeof set[0][j] !== 'string')
+      return true
+  }
+
+  return false
+}
+
+glob.Glob = Glob
+inherits(Glob, EE)
+function Glob (pattern, options, cb) {
+  if (typeof options === 'function') {
+    cb = options
+    options = null
+  }
+
+  if (options && options.sync) {
+    if (cb)
+      throw new TypeError('callback provided to sync glob')
+    return new GlobSync(pattern, options)
+  }
+
+  if (!(this instanceof Glob))
+    return new Glob(pattern, options, cb)
+
+  setopts(this, pattern, options)
+  this._didRealPath = false
+
+  // process each pattern in the minimatch set
+  var n = this.minimatch.set.length
+
+  // The matches are stored as {<filename>: true,...} so that
+  // duplicates are automagically pruned.
+  // Later, we do an Object.keys() on these.
+  // Keep them as a list so we can fill in when nonull is set.
+  this.matches = new Array(n)
+
+  if (typeof cb === 'function') {
+    cb = once(cb)
+    this.on('error', cb)
+    this.on('end', function (matches) {
+      cb(null, matches)
+    })
+  }
+
+  var self = this
+  this._processing = 0
+
+  this._emitQueue = []
+  this._processQueue = []
+  this.paused = false
+
+  if (this.noprocess)
+    return this
+
+  if (n === 0)
+    return done()
+
+  var sync = true
+  for (var i = 0; i < n; i ++) {
+    this._process(this.minimatch.set[i], i, false, done)
+  }
+  sync = false
+
+  function done () {
+    --self._processing
+    if (self._processing <= 0) {
+      if (sync) {
+        process.nextTick(function () {
+          self._finish()
+        })
+      } else {
+        self._finish()
+      }
+    }
+  }
+}
+
+Glob.prototype._finish = function () {
+  assert(this instanceof Glob)
+  if (this.aborted)
+    return
+
+  if (this.realpath && !this._didRealpath)
+    return this._realpath()
+
+  common.finish(this)
+  this.emit('end', this.found)
+}
+
+Glob.prototype._realpath = function () {
+  if (this._didRealpath)
+    return
+
+  this._didRealpath = true
+
+  var n = this.matches.length
+  if (n === 0)
+    return this._finish()
+
+  var self = this
+  for (var i = 0; i < this.matches.length; i++)
+    this._realpathSet(i, next)
+
+  function next () {
+    if (--n === 0)
+      self._finish()
+  }
+}
+
+Glob.prototype._realpathSet = function (index, cb) {
+  var matchset = this.matches[index]
+  if (!matchset)
+    return cb()
+
+  var found = Object.keys(matchset)
+  var self = this
+  var n = found.length
+
+  if (n === 0)
+    return cb()
+
+  var set = this.matches[index] = Object.create(null)
+  found.forEach(function (p, i) {
+    // If there's a problem with the stat, then it means that
+    // one or more of the links in the realpath couldn't be
+    // resolved.  just return the abs value in that case.
+    p = self._makeAbs(p)
+    rp.realpath(p, self.realpathCache, function (er, real) {
+      if (!er)
+        set[real] = true
+      else if (er.syscall === 'stat')
+        set[p] = true
+      else
+        self.emit('error', er) // srsly wtf right here
+
+      if (--n === 0) {
+        self.matches[index] = set
+        cb()
+      }
+    })
+  })
+}
+
+Glob.prototype._mark = function (p) {
+  return common.mark(this, p)
+}
+
+Glob.prototype._makeAbs = function (f) {
+  return common.makeAbs(this, f)
+}
+
+Glob.prototype.abort = function () {
+  this.aborted = true
+  this.emit('abort')
+}
+
+Glob.prototype.pause = function () {
+  if (!this.paused) {
+    this.paused = true
+    this.emit('pause')
+  }
+}
+
+Glob.prototype.resume = function () {
+  if (this.paused) {
+    this.emit('resume')
+    this.paused = false
+    if (this._emitQueue.length) {
+      var eq = this._emitQueue.slice(0)
+      this._emitQueue.length = 0
+      for (var i = 0; i < eq.length; i ++) {
+        var e = eq[i]
+        this._emitMatch(e[0], e[1])
+      }
+    }
+    if (this._processQueue.length) {
+      var pq = this._processQueue.slice(0)
+      this._processQueue.length = 0
+      for (var i = 0; i < pq.length; i ++) {
+        var p = pq[i]
+        this._processing--
+        this._process(p[0], p[1], p[2], p[3])
+      }
+    }
+  }
+}
+
+Glob.prototype._process = function (pattern, index, inGlobStar, cb) {
+  assert(this instanceof Glob)
+  assert(typeof cb === 'function')
+
+  if (this.aborted)
+    return
+
+  this._processing++
+  if (this.paused) {
+    this._processQueue.push([pattern, index, inGlobStar, cb])
+    return
+  }
+
+  //console.error('PROCESS %d', this._processing, pattern)
+
+  // Get the first [n] parts of pattern that are all strings.
+  var n = 0
+  while (typeof pattern[n] === 'string') {
+    n ++
+  }
+  // now n is the index of the first one that is *not* a string.
+
+  // see if there's anything else
+  var prefix
+  switch (n) {
+    // if not, then this is rather simple
+    case pattern.length:
+      this._processSimple(pattern.join('/'), index, cb)
+      return
+
+    case 0:
+      // pattern *starts* with some non-trivial item.
+      // going to readdir(cwd), but not include the prefix in matches.
+      prefix = null
+      break
+
+    default:
+      // pattern has some string bits in the front.
+      // whatever it starts with, whether that's 'absolute' like /foo/bar,
+      // or 'relative' like '../baz'
+      prefix = pattern.slice(0, n).join('/')
+      break
+  }
+
+  var remain = pattern.slice(n)
+
+  // get the list of entries.
+  var read
+  if (prefix === null)
+    read = '.'
+  else if (isAbsolute(prefix) ||
+      isAbsolute(pattern.map(function (p) {
+        return typeof p === 'string' ? p : '[*]'
+      }).join('/'))) {
+    if (!prefix || !isAbsolute(prefix))
+      prefix = '/' + prefix
+    read = prefix
+  } else
+    read = prefix
+
+  var abs = this._makeAbs(read)
+
+  //if ignored, skip _processing
+  if (childrenIgnored(this, read))
+    return cb()
+
+  var isGlobStar = remain[0] === minimatch.GLOBSTAR
+  if (isGlobStar)
+    this._processGlobStar(prefix, read, abs, remain, index, inGlobStar, cb)
+  else
+    this._processReaddir(prefix, read, abs, remain, index, inGlobStar, cb)
+}
+
+Glob.prototype._processReaddir = function (prefix, read, abs, remain, index, inGlobStar, cb) {
+  var self = this
+  this._readdir(abs, inGlobStar, function (er, entries) {
+    return self._processReaddir2(prefix, read, abs, remain, index, inGlobStar, entries, cb)
+  })
+}
+
+Glob.prototype._processReaddir2 = function (prefix, read, abs, remain, index, inGlobStar, entries, cb) {
+
+  // if the abs isn't a dir, then nothing can match!
+  if (!entries)
+    return cb()
+
+  // It will only match dot entries if it starts with a dot, or if
+  // dot is set.  Stuff like @(.foo|.bar) isn't allowed.
+  var pn = remain[0]
+  var negate = !!this.minimatch.negate
+  var rawGlob = pn._glob
+  var dotOk = this.dot || rawGlob.charAt(0) === '.'
+
+  var matchedEntries = []
+  for (var i = 0; i < entries.length; i++) {
+    var e = entries[i]
+    if (e.charAt(0) !== '.' || dotOk) {
+      var m
+      if (negate && !prefix) {
+        m = !e.match(pn)
+      } else {
+        m = e.match(pn)
+      }
+      if (m)
+        matchedEntries.push(e)
+    }
+  }
+
+  //console.error('prd2', prefix, entries, remain[0]._glob, matchedEntries)
+
+  var len = matchedEntries.length
+  // If there are no matched entries, then nothing matches.
+  if (len === 0)
+    return cb()
+
+  // if this is the last remaining pattern bit, then no need for
+  // an additional stat *unless* the user has specified mark or
+  // stat explicitly.  We know they exist, since readdir returned
+  // them.
+
+  if (remain.length === 1 && !this.mark && !this.stat) {
+    if (!this.matches[index])
+      this.matches[index] = Object.create(null)
+
+    for (var i = 0; i < len; i ++) {
+      var e = matchedEntries[i]
+      if (prefix) {
+        if (prefix !== '/')
+          e = prefix + '/' + e
+        else
+          e = prefix + e
+      }
+
+      if (e.charAt(0) === '/' && !this.nomount) {
+        e = path.join(this.root, e)
+      }
+      this._emitMatch(index, e)
+    }
+    // This was the last one, and no stats were needed
+    return cb()
+  }
+
+  // now test all matched entries as stand-ins for that part
+  // of the pattern.
+  remain.shift()
+  for (var i = 0; i < len; i ++) {
+    var e = matchedEntries[i]
+    var newPattern
+    if (prefix) {
+      if (prefix !== '/')
+        e = prefix + '/' + e
+      else
+        e = prefix + e
+    }
+    this._process([e].concat(remain), index, inGlobStar, cb)
+  }
+  cb()
+}
+
+Glob.prototype._emitMatch = function (index, e) {
+  if (this.aborted)
+    return
+
+  if (isIgnored(this, e))
+    return
+
+  if (this.paused) {
+    this._emitQueue.push([index, e])
+    return
+  }
+
+  var abs = isAbsolute(e) ? e : this._makeAbs(e)
+
+  if (this.mark)
+    e = this._mark(e)
+
+  if (this.absolute)
+    e = abs
+
+  if (this.matches[index][e])
+    return
+
+  if (this.nodir) {
+    var c = this.cache[abs]
+    if (c === 'DIR' || Array.isArray(c))
+      return
+  }
+
+  this.matches[index][e] = true
+
+  var st = this.statCache[abs]
+  if (st)
+    this.emit('stat', e, st)
+
+  this.emit('match', e)
+}
+
+Glob.prototype._readdirInGlobStar = function (abs, cb) {
+  if (this.aborted)
+    return
+
+  // follow all symlinked directories forever
+  // just proceed as if this is a non-globstar situation
+  if (this.follow)
+    return this._readdir(abs, false, cb)
+
+  var lstatkey = 'lstat\0' + abs
+  var self = this
+  var lstatcb = inflight(lstatkey, lstatcb_)
+
+  if (lstatcb)
+    self.fs.lstat(abs, lstatcb)
+
+  function lstatcb_ (er, lstat) {
+    if (er && er.code === 'ENOENT')
+      return cb()
+
+    var isSym = lstat && lstat.isSymbolicLink()
+    self.symlinks[abs] = isSym
+
+    // If it's not a symlink or a dir, then it's definitely a regular file.
+    // don't bother doing a readdir in that case.
+    if (!isSym && lstat && !lstat.isDirectory()) {
+      self.cache[abs] = 'FILE'
+      cb()
+    } else
+      self._readdir(abs, false, cb)
+  }
+}
+
+Glob.prototype._readdir = function (abs, inGlobStar, cb) {
+  if (this.aborted)
+    return
+
+  cb = inflight('readdir\0'+abs+'\0'+inGlobStar, cb)
+  if (!cb)
+    return
+
+  //console.error('RD %j %j', +inGlobStar, abs)
+  if (inGlobStar && !ownProp(this.symlinks, abs))
+    return this._readdirInGlobStar(abs, cb)
+
+  if (ownProp(this.cache, abs)) {
+    var c = this.cache[abs]
+    if (!c || c === 'FILE')
+      return cb()
+
+    if (Array.isArray(c))
+      return cb(null, c)
+  }
+
+  var self = this
+  self.fs.readdir(abs, readdirCb(this, abs, cb))
+}
+
+function readdirCb (self, abs, cb) {
+  return function (er, entries) {
+    if (er)
+      self._readdirError(abs, er, cb)
+    else
+      self._readdirEntries(abs, entries, cb)
+  }
+}
+
+Glob.prototype._readdirEntries = function (abs, entries, cb) {
+  if (this.aborted)
+    return
+
+  // if we haven't asked to stat everything, then just
+  // assume that everything in there exists, so we can avoid
+  // having to stat it a second time.
+  if (!this.mark && !this.stat) {
+    for (var i = 0; i < entries.length; i ++) {
+      var e = entries[i]
+      if (abs === '/')
+        e = abs + e
+      else
+        e = abs + '/' + e
+      this.cache[e] = true
+    }
+  }
+
+  this.cache[abs] = entries
+  return cb(null, entries)
+}
+
+Glob.prototype._readdirError = function (f, er, cb) {
+  if (this.aborted)
+    return
+
+  // handle errors, and cache the information
+  switch (er.code) {
+    case 'ENOTSUP': // https://github.com/isaacs/node-glob/issues/205
+    case 'ENOTDIR': // totally normal. means it *does* exist.
+      var abs = this._makeAbs(f)
+      this.cache[abs] = 'FILE'
+      if (abs === this.cwdAbs) {
+        var error = new Error(er.code + ' invalid cwd ' + this.cwd)
+        error.path = this.cwd
+        error.code = er.code
+        this.emit('error', error)
+        this.abort()
+      }
+      break
+
+    case 'ENOENT': // not terribly unusual
+    case 'ELOOP':
+    case 'ENAMETOOLONG':
+    case 'UNKNOWN':
+      this.cache[this._makeAbs(f)] = false
+      break
+
+    default: // some unusual error.  Treat as failure.
+      this.cache[this._makeAbs(f)] = false
+      if (this.strict) {
+        this.emit('error', er)
+        // If the error is handled, then we abort
+        // if not, we threw out of here
+        this.abort()
+      }
+      if (!this.silent)
+        console.error('glob error', er)
+      break
+  }
+
+  return cb()
+}
+
+Glob.prototype._processGlobStar = function (prefix, read, abs, remain, index, inGlobStar, cb) {
+  var self = this
+  this._readdir(abs, inGlobStar, function (er, entries) {
+    self._processGlobStar2(prefix, read, abs, remain, index, inGlobStar, entries, cb)
+  })
+}
+
+
+Glob.prototype._processGlobStar2 = function (prefix, read, abs, remain, index, inGlobStar, entries, cb) {
+  //console.error('pgs2', prefix, remain[0], entries)
+
+  // no entries means not a dir, so it can never have matches
+  // foo.txt/** doesn't match foo.txt
+  if (!entries)
+    return cb()
+
+  // test without the globstar, and with every child both below
+  // and replacing the globstar.
+  var remainWithoutGlobStar = remain.slice(1)
+  var gspref = prefix ? [ prefix ] : []
+  var noGlobStar = gspref.concat(remainWithoutGlobStar)
+
+  // the noGlobStar pattern exits the inGlobStar state
+  this._process(noGlobStar, index, false, cb)
+
+  var isSym = this.symlinks[abs]
+  var len = entries.length
+
+  // If it's a symlink, and we're in a globstar, then stop
+  if (isSym && inGlobStar)
+    return cb()
+
+  for (var i = 0; i < len; i++) {
+    var e = entries[i]
+    if (e.charAt(0) === '.' && !this.dot)
+      continue
+
+    // these two cases enter the inGlobStar state
+    var instead = gspref.concat(entries[i], remainWithoutGlobStar)
+    this._process(instead, index, true, cb)
+
+    var below = gspref.concat(entries[i], remain)
+    this._process(below, index, true, cb)
+  }
+
+  cb()
+}
+
+Glob.prototype._processSimple = function (prefix, index, cb) {
+  // XXX review this.  Shouldn't it be doing the mounting etc
+  // before doing stat?  kinda weird?
+  var self = this
+  this._stat(prefix, function (er, exists) {
+    self._processSimple2(prefix, index, er, exists, cb)
+  })
+}
+Glob.prototype._processSimple2 = function (prefix, index, er, exists, cb) {
+
+  //console.error('ps2', prefix, exists)
+
+  if (!this.matches[index])
+    this.matches[index] = Object.create(null)
+
+  // If it doesn't exist, then just mark the lack of results
+  if (!exists)
+    return cb()
+
+  if (prefix && isAbsolute(prefix) && !this.nomount) {
+    var trail = /[\/\\]$/.test(prefix)
+    if (prefix.charAt(0) === '/') {
+      prefix = path.join(this.root, prefix)
+    } else {
+      prefix = path.resolve(this.root, prefix)
+      if (trail)
+        prefix += '/'
+    }
+  }
+
+  if (process.platform === 'win32')
+    prefix = prefix.replace(/\\/g, '/')
+
+  // Mark this as a match
+  this._emitMatch(index, prefix)
+  cb()
+}
+
+// Returns either 'DIR', 'FILE', or false
+Glob.prototype._stat = function (f, cb) {
+  var abs = this._makeAbs(f)
+  var needDir = f.slice(-1) === '/'
+
+  if (f.length > this.maxLength)
+    return cb()
+
+  if (!this.stat && ownProp(this.cache, abs)) {
+    var c = this.cache[abs]
+
+    if (Array.isArray(c))
+      c = 'DIR'
+
+    // It exists, but maybe not how we need it
+    if (!needDir || c === 'DIR')
+      return cb(null, c)
+
+    if (needDir && c === 'FILE')
+      return cb()
+
+    // otherwise we have to stat, because maybe c=true
+    // if we know it exists, but not what it is.
+  }
+
+  var exists
+  var stat = this.statCache[abs]
+  if (stat !== undefined) {
+    if (stat === false)
+      return cb(null, stat)
+    else {
+      var type = stat.isDirectory() ? 'DIR' : 'FILE'
+      if (needDir && type === 'FILE')
+        return cb()
+      else
+        return cb(null, type, stat)
+    }
+  }
+
+  var self = this
+  var statcb = inflight('stat\0' + abs, lstatcb_)
+  if (statcb)
+    self.fs.lstat(abs, statcb)
+
+  function lstatcb_ (er, lstat) {
+    if (lstat && lstat.isSymbolicLink()) {
+      // If it's a symlink, then treat it as the target, unless
+      // the target does not exist, then treat it as a file.
+      return self.fs.stat(abs, function (er, stat) {
+        if (er)
+          self._stat2(f, abs, null, lstat, cb)
+        else
+          self._stat2(f, abs, er, stat, cb)
+      })
+    } else {
+      self._stat2(f, abs, er, lstat, cb)
+    }
+  }
+}
+
+Glob.prototype._stat2 = function (f, abs, er, stat, cb) {
+  if (er && (er.code === 'ENOENT' || er.code === 'ENOTDIR')) {
+    this.statCache[abs] = false
+    return cb()
+  }
+
+  var needDir = f.slice(-1) === '/'
+  this.statCache[abs] = stat
+
+  if (abs.slice(-1) === '/' && stat && !stat.isDirectory())
+    return cb(null, false, stat)
+
+  var c = true
+  if (stat)
+    c = stat.isDirectory() ? 'DIR' : 'FILE'
+  this.cache[abs] = this.cache[abs] || c
+
+  if (needDir && c === 'FILE')
+    return cb()
+
+  return cb(null, c, stat)
+}
diff --git a/server/node_modules/glob/package.json b/server/node_modules/glob/package.json
new file mode 100644
index 0000000..5940b64
--- /dev/null
+++ b/server/node_modules/glob/package.json
@@ -0,0 +1,55 @@
+{
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "name": "glob",
+  "description": "a little globber",
+  "version": "7.2.3",
+  "publishConfig": {
+    "tag": "v7-legacy"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/isaacs/node-glob.git"
+  },
+  "main": "glob.js",
+  "files": [
+    "glob.js",
+    "sync.js",
+    "common.js"
+  ],
+  "engines": {
+    "node": "*"
+  },
+  "dependencies": {
+    "fs.realpath": "^1.0.0",
+    "inflight": "^1.0.4",
+    "inherits": "2",
+    "minimatch": "^3.1.1",
+    "once": "^1.3.0",
+    "path-is-absolute": "^1.0.0"
+  },
+  "devDependencies": {
+    "memfs": "^3.2.0",
+    "mkdirp": "0",
+    "rimraf": "^2.2.8",
+    "tap": "^15.0.6",
+    "tick": "0.0.6"
+  },
+  "tap": {
+    "before": "test/00-setup.js",
+    "after": "test/zz-cleanup.js",
+    "jobs": 1
+  },
+  "scripts": {
+    "prepublish": "npm run benchclean",
+    "profclean": "rm -f v8.log profile.txt",
+    "test": "tap",
+    "test-regen": "npm run profclean && TEST_REGEN=1 node test/00-setup.js",
+    "bench": "bash benchmark.sh",
+    "prof": "bash prof.sh && cat profile.txt",
+    "benchclean": "node benchclean.js"
+  },
+  "license": "ISC",
+  "funding": {
+    "url": "https://github.com/sponsors/isaacs"
+  }
+}
diff --git a/server/node_modules/glob/sync.js b/server/node_modules/glob/sync.js
new file mode 100644
index 0000000..2c4f480
--- /dev/null
+++ b/server/node_modules/glob/sync.js
@@ -0,0 +1,486 @@
+module.exports = globSync
+globSync.GlobSync = GlobSync
+
+var rp = require('fs.realpath')
+var minimatch = require('minimatch')
+var Minimatch = minimatch.Minimatch
+var Glob = require('./glob.js').Glob
+var util = require('util')
+var path = require('path')
+var assert = require('assert')
+var isAbsolute = require('path-is-absolute')
+var common = require('./common.js')
+var setopts = common.setopts
+var ownProp = common.ownProp
+var childrenIgnored = common.childrenIgnored
+var isIgnored = common.isIgnored
+
+function globSync (pattern, options) {
+  if (typeof options === 'function' || arguments.length === 3)
+    throw new TypeError('callback provided to sync glob\n'+
+                        'See: https://github.com/isaacs/node-glob/issues/167')
+
+  return new GlobSync(pattern, options).found
+}
+
+function GlobSync (pattern, options) {
+  if (!pattern)
+    throw new Error('must provide pattern')
+
+  if (typeof options === 'function' || arguments.length === 3)
+    throw new TypeError('callback provided to sync glob\n'+
+                        'See: https://github.com/isaacs/node-glob/issues/167')
+
+  if (!(this instanceof GlobSync))
+    return new GlobSync(pattern, options)
+
+  setopts(this, pattern, options)
+
+  if (this.noprocess)
+    return this
+
+  var n = this.minimatch.set.length
+  this.matches = new Array(n)
+  for (var i = 0; i < n; i ++) {
+    this._process(this.minimatch.set[i], i, false)
+  }
+  this._finish()
+}
+
+GlobSync.prototype._finish = function () {
+  assert.ok(this instanceof GlobSync)
+  if (this.realpath) {
+    var self = this
+    this.matches.forEach(function (matchset, index) {
+      var set = self.matches[index] = Object.create(null)
+      for (var p in matchset) {
+        try {
+          p = self._makeAbs(p)
+          var real = rp.realpathSync(p, self.realpathCache)
+          set[real] = true
+        } catch (er) {
+          if (er.syscall === 'stat')
+            set[self._makeAbs(p)] = true
+          else
+            throw er
+        }
+      }
+    })
+  }
+  common.finish(this)
+}
+
+
+GlobSync.prototype._process = function (pattern, index, inGlobStar) {
+  assert.ok(this instanceof GlobSync)
+
+  // Get the first [n] parts of pattern that are all strings.
+  var n = 0
+  while (typeof pattern[n] === 'string') {
+    n ++
+  }
+  // now n is the index of the first one that is *not* a string.
+
+  // See if there's anything else
+  var prefix
+  switch (n) {
+    // if not, then this is rather simple
+    case pattern.length:
+      this._processSimple(pattern.join('/'), index)
+      return
+
+    case 0:
+      // pattern *starts* with some non-trivial item.
+      // going to readdir(cwd), but not include the prefix in matches.
+      prefix = null
+      break
+
+    default:
+      // pattern has some string bits in the front.
+      // whatever it starts with, whether that's 'absolute' like /foo/bar,
+      // or 'relative' like '../baz'
+      prefix = pattern.slice(0, n).join('/')
+      break
+  }
+
+  var remain = pattern.slice(n)
+
+  // get the list of entries.
+  var read
+  if (prefix === null)
+    read = '.'
+  else if (isAbsolute(prefix) ||
+      isAbsolute(pattern.map(function (p) {
+        return typeof p === 'string' ? p : '[*]'
+      }).join('/'))) {
+    if (!prefix || !isAbsolute(prefix))
+      prefix = '/' + prefix
+    read = prefix
+  } else
+    read = prefix
+
+  var abs = this._makeAbs(read)
+
+  //if ignored, skip processing
+  if (childrenIgnored(this, read))
+    return
+
+  var isGlobStar = remain[0] === minimatch.GLOBSTAR
+  if (isGlobStar)
+    this._processGlobStar(prefix, read, abs, remain, index, inGlobStar)
+  else
+    this._processReaddir(prefix, read, abs, remain, index, inGlobStar)
+}
+
+
+GlobSync.prototype._processReaddir = function (prefix, read, abs, remain, index, inGlobStar) {
+  var entries = this._readdir(abs, inGlobStar)
+
+  // if the abs isn't a dir, then nothing can match!
+  if (!entries)
+    return
+
+  // It will only match dot entries if it starts with a dot, or if
+  // dot is set.  Stuff like @(.foo|.bar) isn't allowed.
+  var pn = remain[0]
+  var negate = !!this.minimatch.negate
+  var rawGlob = pn._glob
+  var dotOk = this.dot || rawGlob.charAt(0) === '.'
+
+  var matchedEntries = []
+  for (var i = 0; i < entries.length; i++) {
+    var e = entries[i]
+    if (e.charAt(0) !== '.' || dotOk) {
+      var m
+      if (negate && !prefix) {
+        m = !e.match(pn)
+      } else {
+        m = e.match(pn)
+      }
+      if (m)
+        matchedEntries.push(e)
+    }
+  }
+
+  var len = matchedEntries.length
+  // If there are no matched entries, then nothing matches.
+  if (len === 0)
+    return
+
+  // if this is the last remaining pattern bit, then no need for
+  // an additional stat *unless* the user has specified mark or
+  // stat explicitly.  We know they exist, since readdir returned
+  // them.
+
+  if (remain.length === 1 && !this.mark && !this.stat) {
+    if (!this.matches[index])
+      this.matches[index] = Object.create(null)
+
+    for (var i = 0; i < len; i ++) {
+      var e = matchedEntries[i]
+      if (prefix) {
+        if (prefix.slice(-1) !== '/')
+          e = prefix + '/' + e
+        else
+          e = prefix + e
+      }
+
+      if (e.charAt(0) === '/' && !this.nomount) {
+        e = path.join(this.root, e)
+      }
+      this._emitMatch(index, e)
+    }
+    // This was the last one, and no stats were needed
+    return
+  }
+
+  // now test all matched entries as stand-ins for that part
+  // of the pattern.
+  remain.shift()
+  for (var i = 0; i < len; i ++) {
+    var e = matchedEntries[i]
+    var newPattern
+    if (prefix)
+      newPattern = [prefix, e]
+    else
+      newPattern = [e]
+    this._process(newPattern.concat(remain), index, inGlobStar)
+  }
+}
+
+
+GlobSync.prototype._emitMatch = function (index, e) {
+  if (isIgnored(this, e))
+    return
+
+  var abs = this._makeAbs(e)
+
+  if (this.mark)
+    e = this._mark(e)
+
+  if (this.absolute) {
+    e = abs
+  }
+
+  if (this.matches[index][e])
+    return
+
+  if (this.nodir) {
+    var c = this.cache[abs]
+    if (c === 'DIR' || Array.isArray(c))
+      return
+  }
+
+  this.matches[index][e] = true
+
+  if (this.stat)
+    this._stat(e)
+}
+
+
+GlobSync.prototype._readdirInGlobStar = function (abs) {
+  // follow all symlinked directories forever
+  // just proceed as if this is a non-globstar situation
+  if (this.follow)
+    return this._readdir(abs, false)
+
+  var entries
+  var lstat
+  var stat
+  try {
+    lstat = this.fs.lstatSync(abs)
+  } catch (er) {
+    if (er.code === 'ENOENT') {
+      // lstat failed, doesn't exist
+      return null
+    }
+  }
+
+  var isSym = lstat && lstat.isSymbolicLink()
+  this.symlinks[abs] = isSym
+
+  // If it's not a symlink or a dir, then it's definitely a regular file.
+  // don't bother doing a readdir in that case.
+  if (!isSym && lstat && !lstat.isDirectory())
+    this.cache[abs] = 'FILE'
+  else
+    entries = this._readdir(abs, false)
+
+  return entries
+}
+
+GlobSync.prototype._readdir = function (abs, inGlobStar) {
+  var entries
+
+  if (inGlobStar && !ownProp(this.symlinks, abs))
+    return this._readdirInGlobStar(abs)
+
+  if (ownProp(this.cache, abs)) {
+    var c = this.cache[abs]
+    if (!c || c === 'FILE')
+      return null
+
+    if (Array.isArray(c))
+      return c
+  }
+
+  try {
+    return this._readdirEntries(abs, this.fs.readdirSync(abs))
+  } catch (er) {
+    this._readdirError(abs, er)
+    return null
+  }
+}
+
+GlobSync.prototype._readdirEntries = function (abs, entries) {
+  // if we haven't asked to stat everything, then just
+  // assume that everything in there exists, so we can avoid
+  // having to stat it a second time.
+  if (!this.mark && !this.stat) {
+    for (var i = 0; i < entries.length; i ++) {
+      var e = entries[i]
+      if (abs === '/')
+        e = abs + e
+      else
+        e = abs + '/' + e
+      this.cache[e] = true
+    }
+  }
+
+  this.cache[abs] = entries
+
+  // mark and cache dir-ness
+  return entries
+}
+
+GlobSync.prototype._readdirError = function (f, er) {
+  // handle errors, and cache the information
+  switch (er.code) {
+    case 'ENOTSUP': // https://github.com/isaacs/node-glob/issues/205
+    case 'ENOTDIR': // totally normal. means it *does* exist.
+      var abs = this._makeAbs(f)
+      this.cache[abs] = 'FILE'
+      if (abs === this.cwdAbs) {
+        var error = new Error(er.code + ' invalid cwd ' + this.cwd)
+        error.path = this.cwd
+        error.code = er.code
+        throw error
+      }
+      break
+
+    case 'ENOENT': // not terribly unusual
+    case 'ELOOP':
+    case 'ENAMETOOLONG':
+    case 'UNKNOWN':
+      this.cache[this._makeAbs(f)] = false
+      break
+
+    default: // some unusual error.  Treat as failure.
+      this.cache[this._makeAbs(f)] = false
+      if (this.strict)
+        throw er
+      if (!this.silent)
+        console.error('glob error', er)
+      break
+  }
+}
+
+GlobSync.prototype._processGlobStar = function (prefix, read, abs, remain, index, inGlobStar) {
+
+  var entries = this._readdir(abs, inGlobStar)
+
+  // no entries means not a dir, so it can never have matches
+  // foo.txt/** doesn't match foo.txt
+  if (!entries)
+    return
+
+  // test without the globstar, and with every child both below
+  // and replacing the globstar.
+  var remainWithoutGlobStar = remain.slice(1)
+  var gspref = prefix ? [ prefix ] : []
+  var noGlobStar = gspref.concat(remainWithoutGlobStar)
+
+  // the noGlobStar pattern exits the inGlobStar state
+  this._process(noGlobStar, index, false)
+
+  var len = entries.length
+  var isSym = this.symlinks[abs]
+
+  // If it's a symlink, and we're in a globstar, then stop
+  if (isSym && inGlobStar)
+    return
+
+  for (var i = 0; i < len; i++) {
+    var e = entries[i]
+    if (e.charAt(0) === '.' && !this.dot)
+      continue
+
+    // these two cases enter the inGlobStar state
+    var instead = gspref.concat(entries[i], remainWithoutGlobStar)
+    this._process(instead, index, true)
+
+    var below = gspref.concat(entries[i], remain)
+    this._process(below, index, true)
+  }
+}
+
+GlobSync.prototype._processSimple = function (prefix, index) {
+  // XXX review this.  Shouldn't it be doing the mounting etc
+  // before doing stat?  kinda weird?
+  var exists = this._stat(prefix)
+
+  if (!this.matches[index])
+    this.matches[index] = Object.create(null)
+
+  // If it doesn't exist, then just mark the lack of results
+  if (!exists)
+    return
+
+  if (prefix && isAbsolute(prefix) && !this.nomount) {
+    var trail = /[\/\\]$/.test(prefix)
+    if (prefix.charAt(0) === '/') {
+      prefix = path.join(this.root, prefix)
+    } else {
+      prefix = path.resolve(this.root, prefix)
+      if (trail)
+        prefix += '/'
+    }
+  }
+
+  if (process.platform === 'win32')
+    prefix = prefix.replace(/\\/g, '/')
+
+  // Mark this as a match
+  this._emitMatch(index, prefix)
+}
+
+// Returns either 'DIR', 'FILE', or false
+GlobSync.prototype._stat = function (f) {
+  var abs = this._makeAbs(f)
+  var needDir = f.slice(-1) === '/'
+
+  if (f.length > this.maxLength)
+    return false
+
+  if (!this.stat && ownProp(this.cache, abs)) {
+    var c = this.cache[abs]
+
+    if (Array.isArray(c))
+      c = 'DIR'
+
+    // It exists, but maybe not how we need it
+    if (!needDir || c === 'DIR')
+      return c
+
+    if (needDir && c === 'FILE')
+      return false
+
+    // otherwise we have to stat, because maybe c=true
+    // if we know it exists, but not what it is.
+  }
+
+  var exists
+  var stat = this.statCache[abs]
+  if (!stat) {
+    var lstat
+    try {
+      lstat = this.fs.lstatSync(abs)
+    } catch (er) {
+      if (er && (er.code === 'ENOENT' || er.code === 'ENOTDIR')) {
+        this.statCache[abs] = false
+        return false
+      }
+    }
+
+    if (lstat && lstat.isSymbolicLink()) {
+      try {
+        stat = this.fs.statSync(abs)
+      } catch (er) {
+        stat = lstat
+      }
+    } else {
+      stat = lstat
+    }
+  }
+
+  this.statCache[abs] = stat
+
+  var c = true
+  if (stat)
+    c = stat.isDirectory() ? 'DIR' : 'FILE'
+
+  this.cache[abs] = this.cache[abs] || c
+
+  if (needDir && c === 'FILE')
+    return false
+
+  return c
+}
+
+GlobSync.prototype._mark = function (p) {
+  return common.mark(this, p)
+}
+
+GlobSync.prototype._makeAbs = function (f) {
+  return common.makeAbs(this, f)
+}
diff --git a/server/node_modules/gopd/.eslintrc b/server/node_modules/gopd/.eslintrc
new file mode 100644
index 0000000..e2550c0
--- /dev/null
+++ b/server/node_modules/gopd/.eslintrc
@@ -0,0 +1,16 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"func-style": [2, "declaration"],
+		"id-length": 0,
+		"multiline-comment-style": 0,
+		"new-cap": [2, {
+			"capIsNewExceptions": [
+				"GetIntrinsic",
+			],
+		}],
+	},
+}
diff --git a/server/node_modules/gopd/.github/FUNDING.yml b/server/node_modules/gopd/.github/FUNDING.yml
new file mode 100644
index 0000000..94a44a8
--- /dev/null
+++ b/server/node_modules/gopd/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/gopd
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/gopd/CHANGELOG.md b/server/node_modules/gopd/CHANGELOG.md
new file mode 100644
index 0000000..87f5727
--- /dev/null
+++ b/server/node_modules/gopd/CHANGELOG.md
@@ -0,0 +1,45 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.2.0](https://github.com/ljharb/gopd/compare/v1.1.0...v1.2.0) - 2024-12-03
+
+### Commits
+
+- [New] add `gOPD` entry point; remove `get-intrinsic` [`5b61232`](https://github.com/ljharb/gopd/commit/5b61232dedea4591a314bcf16101b1961cee024e)
+
+## [v1.1.0](https://github.com/ljharb/gopd/compare/v1.0.1...v1.1.0) - 2024-11-29
+
+### Commits
+
+- [New] add types [`f585e39`](https://github.com/ljharb/gopd/commit/f585e397886d270e4ba84e53d226e4f9ca2eb0e6)
+- [Dev Deps] update `@ljharb/eslint-config`, `auto-changelog`, `tape` [`0b8e4fd`](https://github.com/ljharb/gopd/commit/0b8e4fded64397a7726a9daa144a6cc9a5e2edfa)
+- [Dev Deps] update `aud`, `npmignore`, `tape` [`48378b2`](https://github.com/ljharb/gopd/commit/48378b2443f09a4f7efbd0fb6c3ee845a6cabcf3)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud`, `tape` [`78099ee`](https://github.com/ljharb/gopd/commit/78099eeed41bfdc134c912280483689cc8861c31)
+- [Tests] replace `aud` with `npm audit` [`4e0d0ac`](https://github.com/ljharb/gopd/commit/4e0d0ac47619d24a75318a8e1f543ee04b2a2632)
+- [meta] add missing `engines.node` [`1443316`](https://github.com/ljharb/gopd/commit/14433165d07835c680155b3dfd62d9217d735eca)
+- [Deps] update `get-intrinsic` [`eee5f51`](https://github.com/ljharb/gopd/commit/eee5f51769f3dbaf578b70e2a3199116b01aa670)
+- [Deps] update `get-intrinsic` [`550c378`](https://github.com/ljharb/gopd/commit/550c3780e3a9c77b62565712a001b4ed64ea61f5)
+- [Dev Deps] add missing peer dep [`8c2ecf8`](https://github.com/ljharb/gopd/commit/8c2ecf848122e4e30abfc5b5086fb48b390dce75)
+
+## [v1.0.1](https://github.com/ljharb/gopd/compare/v1.0.0...v1.0.1) - 2022-11-01
+
+### Commits
+
+- [Fix] actually export gOPD instead of dP [`4b624bf`](https://github.com/ljharb/gopd/commit/4b624bfbeff788c5e3ff16d9443a83627847234f)
+
+## v1.0.0 - 2022-11-01
+
+### Commits
+
+- Initial implementation, tests, readme [`0911e01`](https://github.com/ljharb/gopd/commit/0911e012cd642092bd88b732c161c58bf4f20bea)
+- Initial commit [`b84e33f`](https://github.com/ljharb/gopd/commit/b84e33f5808a805ac57ff88d4247ad935569acbe)
+- [actions] add reusable workflows [`12ae28a`](https://github.com/ljharb/gopd/commit/12ae28ae5f50f86e750215b6e2188901646d0119)
+- npm init [`280118b`](https://github.com/ljharb/gopd/commit/280118badb45c80b4483836b5cb5315bddf6e582)
+- [meta] add `auto-changelog` [`bb78de5`](https://github.com/ljharb/gopd/commit/bb78de5639a180747fb290c28912beaaf1615709)
+- [meta] create FUNDING.yml; add `funding` in package.json [`11c22e6`](https://github.com/ljharb/gopd/commit/11c22e6355bb01f24e7fac4c9bb3055eb5b25002)
+- [meta] use `npmignore` to autogenerate an npmignore file [`4f4537a`](https://github.com/ljharb/gopd/commit/4f4537a843b39f698c52f072845092e6fca345bb)
+- Only apps should have lockfiles [`c567022`](https://github.com/ljharb/gopd/commit/c567022a18573aa7951cf5399445d9840e23e98b)
diff --git a/server/node_modules/gopd/LICENSE b/server/node_modules/gopd/LICENSE
new file mode 100644
index 0000000..6abfe14
--- /dev/null
+++ b/server/node_modules/gopd/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/gopd/README.md b/server/node_modules/gopd/README.md
new file mode 100644
index 0000000..784e56a
--- /dev/null
+++ b/server/node_modules/gopd/README.md
@@ -0,0 +1,40 @@
+# gopd <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+`Object.getOwnPropertyDescriptor`, but accounts for IE's broken implementation.
+
+## Usage
+
+```javascript
+var gOPD = require('gopd');
+var assert = require('assert');
+
+if (gOPD) {
+	assert.equal(typeof gOPD, 'function', 'descriptors supported');
+	// use gOPD like Object.getOwnPropertyDescriptor here
+} else {
+	assert.ok(!gOPD, 'descriptors not supported');
+}
+```
+
+[package-url]: https://npmjs.org/package/gopd
+[npm-version-svg]: https://versionbadg.es/ljharb/gopd.svg
+[deps-svg]: https://david-dm.org/ljharb/gopd.svg
+[deps-url]: https://david-dm.org/ljharb/gopd
+[dev-deps-svg]: https://david-dm.org/ljharb/gopd/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/gopd#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/gopd.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/gopd.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/gopd.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=gopd
+[codecov-image]: https://codecov.io/gh/ljharb/gopd/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/gopd/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/gopd
+[actions-url]: https://github.com/ljharb/gopd/actions
diff --git a/server/node_modules/gopd/gOPD.d.ts b/server/node_modules/gopd/gOPD.d.ts
new file mode 100644
index 0000000..def48a3
--- /dev/null
+++ b/server/node_modules/gopd/gOPD.d.ts
@@ -0,0 +1 @@
+export = Object.getOwnPropertyDescriptor;
diff --git a/server/node_modules/gopd/gOPD.js b/server/node_modules/gopd/gOPD.js
new file mode 100644
index 0000000..cf9616c
--- /dev/null
+++ b/server/node_modules/gopd/gOPD.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./gOPD')} */
+module.exports = Object.getOwnPropertyDescriptor;
diff --git a/server/node_modules/gopd/index.d.ts b/server/node_modules/gopd/index.d.ts
new file mode 100644
index 0000000..e228065
--- /dev/null
+++ b/server/node_modules/gopd/index.d.ts
@@ -0,0 +1,5 @@
+declare function gOPD<O extends object, K extends keyof O>(obj: O, prop: K): PropertyDescriptor | undefined;
+
+declare const fn: typeof gOPD | undefined | null;
+
+export = fn;
\ No newline at end of file
diff --git a/server/node_modules/gopd/index.js b/server/node_modules/gopd/index.js
new file mode 100644
index 0000000..a4081b0
--- /dev/null
+++ b/server/node_modules/gopd/index.js
@@ -0,0 +1,15 @@
+'use strict';
+
+/** @type {import('.')} */
+var $gOPD = require('./gOPD');
+
+if ($gOPD) {
+	try {
+		$gOPD([], 'length');
+	} catch (e) {
+		// IE 8 has a broken gOPD
+		$gOPD = null;
+	}
+}
+
+module.exports = $gOPD;
diff --git a/server/node_modules/gopd/package.json b/server/node_modules/gopd/package.json
new file mode 100644
index 0000000..01c5ffa
--- /dev/null
+++ b/server/node_modules/gopd/package.json
@@ -0,0 +1,77 @@
+{
+	"name": "gopd",
+	"version": "1.2.0",
+	"description": "`Object.getOwnPropertyDescriptor`, but accounts for IE's broken implementation.",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./gOPD": "./gOPD.js",
+		"./package.json": "./package.json"
+	},
+	"sideEffects": false,
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prelint": "tsc -p . && attw -P",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "evalmd README.md",
+		"pretest": "npm run lint",
+		"tests-only": "tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>=10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/gopd.git"
+	},
+	"keywords": [
+		"ecmascript",
+		"javascript",
+		"getownpropertydescriptor",
+		"property",
+		"descriptor"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"funding": {
+		"url": "https://github.com/sponsors/ljharb"
+	},
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/gopd/issues"
+	},
+	"homepage": "https://github.com/ljharb/gopd#readme",
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.0",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.0",
+		"@types/tape": "^5.6.5",
+		"auto-changelog": "^2.5.0",
+		"encoding": "^0.1.13",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/gopd/test/index.js b/server/node_modules/gopd/test/index.js
new file mode 100644
index 0000000..6f43453
--- /dev/null
+++ b/server/node_modules/gopd/test/index.js
@@ -0,0 +1,36 @@
+'use strict';
+
+var test = require('tape');
+var gOPD = require('../');
+
+test('gOPD', function (t) {
+	t.test('supported', { skip: !gOPD }, function (st) {
+		st.equal(typeof gOPD, 'function', 'is a function');
+
+		var obj = { x: 1 };
+		st.ok('x' in obj, 'property exists');
+
+		// @ts-expect-error TS can't figure out narrowing from `skip`
+		var desc = gOPD(obj, 'x');
+		st.deepEqual(
+			desc,
+			{
+				configurable: true,
+				enumerable: true,
+				value: 1,
+				writable: true
+			},
+			'descriptor is as expected'
+		);
+
+		st.end();
+	});
+
+	t.test('not supported', { skip: !!gOPD }, function (st) {
+		st.notOk(gOPD, 'is falsy');
+
+		st.end();
+	});
+
+	t.end();
+});
diff --git a/server/node_modules/gopd/tsconfig.json b/server/node_modules/gopd/tsconfig.json
new file mode 100644
index 0000000..d9a6668
--- /dev/null
+++ b/server/node_modules/gopd/tsconfig.json
@@ -0,0 +1,9 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "es2021",
+	},
+	"exclude": [
+		"coverage",
+	],
+}
diff --git a/server/node_modules/graceful-fs/LICENSE b/server/node_modules/graceful-fs/LICENSE
new file mode 100644
index 0000000..e906a25
--- /dev/null
+++ b/server/node_modules/graceful-fs/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) 2011-2022 Isaac Z. Schlueter, Ben Noordhuis, and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/graceful-fs/README.md b/server/node_modules/graceful-fs/README.md
new file mode 100644
index 0000000..82d6e4d
--- /dev/null
+++ b/server/node_modules/graceful-fs/README.md
@@ -0,0 +1,143 @@
+# graceful-fs
+
+graceful-fs functions as a drop-in replacement for the fs module,
+making various improvements.
+
+The improvements are meant to normalize behavior across different
+platforms and environments, and to make filesystem access more
+resilient to errors.
+
+## Improvements over [fs module](https://nodejs.org/api/fs.html)
+
+* Queues up `open` and `readdir` calls, and retries them once
+  something closes if there is an EMFILE error from too many file
+  descriptors.
+* fixes `lchmod` for Node versions prior to 0.6.2.
+* implements `fs.lutimes` if possible. Otherwise it becomes a noop.
+* ignores `EINVAL` and `EPERM` errors in `chown`, `fchown` or
+  `lchown` if the user isn't root.
+* makes `lchmod` and `lchown` become noops, if not available.
+* retries reading a file if `read` results in EAGAIN error.
+
+On Windows, it retries renaming a file for up to one second if `EACCESS`
+or `EPERM` error occurs, likely because antivirus software has locked
+the directory.
+
+## USAGE
+
+```javascript
+// use just like fs
+var fs = require('graceful-fs')
+
+// now go and do stuff with it...
+fs.readFile('some-file-or-whatever', (err, data) => {
+  // Do stuff here.
+})
+```
+
+## Sync methods
+
+This module cannot intercept or handle `EMFILE` or `ENFILE` errors from sync
+methods.  If you use sync methods which open file descriptors then you are
+responsible for dealing with any errors.
+
+This is a known limitation, not a bug.
+
+## Global Patching
+
+If you want to patch the global fs module (or any other fs-like
+module) you can do this:
+
+```javascript
+// Make sure to read the caveat below.
+var realFs = require('fs')
+var gracefulFs = require('graceful-fs')
+gracefulFs.gracefulify(realFs)
+```
+
+This should only ever be done at the top-level application layer, in
+order to delay on EMFILE errors from any fs-using dependencies.  You
+should **not** do this in a library, because it can cause unexpected
+delays in other parts of the program.
+
+## Changes
+
+This module is fairly stable at this point, and used by a lot of
+things.  That being said, because it implements a subtle behavior
+change in a core part of the node API, even modest changes can be
+extremely breaking, and the versioning is thus biased towards
+bumping the major when in doubt.
+
+The main change between major versions has been switching between
+providing a fully-patched `fs` module vs monkey-patching the node core
+builtin, and the approach by which a non-monkey-patched `fs` was
+created.
+
+The goal is to trade `EMFILE` errors for slower fs operations.  So, if
+you try to open a zillion files, rather than crashing, `open`
+operations will be queued up and wait for something else to `close`.
+
+There are advantages to each approach.  Monkey-patching the fs means
+that no `EMFILE` errors can possibly occur anywhere in your
+application, because everything is using the same core `fs` module,
+which is patched.  However, it can also obviously cause undesirable
+side-effects, especially if the module is loaded multiple times.
+
+Implementing a separate-but-identical patched `fs` module is more
+surgical (and doesn't run the risk of patching multiple times), but
+also imposes the challenge of keeping in sync with the core module.
+
+The current approach loads the `fs` module, and then creates a
+lookalike object that has all the same methods, except a few that are
+patched.  It is safe to use in all versions of Node from 0.8 through
+7.0.
+
+### v4
+
+* Do not monkey-patch the fs module.  This module may now be used as a
+  drop-in dep, and users can opt into monkey-patching the fs builtin
+  if their app requires it.
+
+### v3
+
+* Monkey-patch fs, because the eval approach no longer works on recent
+  node.
+* fixed possible type-error throw if rename fails on windows
+* verify that we *never* get EMFILE errors
+* Ignore ENOSYS from chmod/chown
+* clarify that graceful-fs must be used as a drop-in
+
+### v2.1.0
+
+* Use eval rather than monkey-patching fs.
+* readdir: Always sort the results
+* win32: requeue a file if error has an OK status
+
+### v2.0
+
+* A return to monkey patching
+* wrap process.cwd
+
+### v1.1
+
+* wrap readFile
+* Wrap fs.writeFile.
+* readdir protection
+* Don't clobber the fs builtin
+* Handle fs.read EAGAIN errors by trying again
+* Expose the curOpen counter
+* No-op lchown/lchmod if not implemented
+* fs.rename patch only for win32
+* Patch fs.rename to handle AV software on Windows
+* Close #4 Chown should not fail on einval or eperm if non-root
+* Fix isaacs/fstream#1 Only wrap fs one time
+* Fix #3 Start at 1024 max files, then back off on EMFILE
+* lutimes that doens't blow up on Linux
+* A full on-rewrite using a queue instead of just swallowing the EMFILE error
+* Wrap Read/Write streams as well
+
+### 1.0
+
+* Update engines for node 0.6
+* Be lstat-graceful on Windows
+* first
diff --git a/server/node_modules/graceful-fs/clone.js b/server/node_modules/graceful-fs/clone.js
new file mode 100644
index 0000000..dff3cc8
--- /dev/null
+++ b/server/node_modules/graceful-fs/clone.js
@@ -0,0 +1,23 @@
+'use strict'
+
+module.exports = clone
+
+var getPrototypeOf = Object.getPrototypeOf || function (obj) {
+  return obj.__proto__
+}
+
+function clone (obj) {
+  if (obj === null || typeof obj !== 'object')
+    return obj
+
+  if (obj instanceof Object)
+    var copy = { __proto__: getPrototypeOf(obj) }
+  else
+    var copy = Object.create(null)
+
+  Object.getOwnPropertyNames(obj).forEach(function (key) {
+    Object.defineProperty(copy, key, Object.getOwnPropertyDescriptor(obj, key))
+  })
+
+  return copy
+}
diff --git a/server/node_modules/graceful-fs/graceful-fs.js b/server/node_modules/graceful-fs/graceful-fs.js
new file mode 100644
index 0000000..8d5b89e
--- /dev/null
+++ b/server/node_modules/graceful-fs/graceful-fs.js
@@ -0,0 +1,448 @@
+var fs = require('fs')
+var polyfills = require('./polyfills.js')
+var legacy = require('./legacy-streams.js')
+var clone = require('./clone.js')
+
+var util = require('util')
+
+/* istanbul ignore next - node 0.x polyfill */
+var gracefulQueue
+var previousSymbol
+
+/* istanbul ignore else - node 0.x polyfill */
+if (typeof Symbol === 'function' && typeof Symbol.for === 'function') {
+  gracefulQueue = Symbol.for('graceful-fs.queue')
+  // This is used in testing by future versions
+  previousSymbol = Symbol.for('graceful-fs.previous')
+} else {
+  gracefulQueue = '___graceful-fs.queue'
+  previousSymbol = '___graceful-fs.previous'
+}
+
+function noop () {}
+
+function publishQueue(context, queue) {
+  Object.defineProperty(context, gracefulQueue, {
+    get: function() {
+      return queue
+    }
+  })
+}
+
+var debug = noop
+if (util.debuglog)
+  debug = util.debuglog('gfs4')
+else if (/\bgfs4\b/i.test(process.env.NODE_DEBUG || ''))
+  debug = function() {
+    var m = util.format.apply(util, arguments)
+    m = 'GFS4: ' + m.split(/\n/).join('\nGFS4: ')
+    console.error(m)
+  }
+
+// Once time initialization
+if (!fs[gracefulQueue]) {
+  // This queue can be shared by multiple loaded instances
+  var queue = global[gracefulQueue] || []
+  publishQueue(fs, queue)
+
+  // Patch fs.close/closeSync to shared queue version, because we need
+  // to retry() whenever a close happens *anywhere* in the program.
+  // This is essential when multiple graceful-fs instances are
+  // in play at the same time.
+  fs.close = (function (fs$close) {
+    function close (fd, cb) {
+      return fs$close.call(fs, fd, function (err) {
+        // This function uses the graceful-fs shared queue
+        if (!err) {
+          resetQueue()
+        }
+
+        if (typeof cb === 'function')
+          cb.apply(this, arguments)
+      })
+    }
+
+    Object.defineProperty(close, previousSymbol, {
+      value: fs$close
+    })
+    return close
+  })(fs.close)
+
+  fs.closeSync = (function (fs$closeSync) {
+    function closeSync (fd) {
+      // This function uses the graceful-fs shared queue
+      fs$closeSync.apply(fs, arguments)
+      resetQueue()
+    }
+
+    Object.defineProperty(closeSync, previousSymbol, {
+      value: fs$closeSync
+    })
+    return closeSync
+  })(fs.closeSync)
+
+  if (/\bgfs4\b/i.test(process.env.NODE_DEBUG || '')) {
+    process.on('exit', function() {
+      debug(fs[gracefulQueue])
+      require('assert').equal(fs[gracefulQueue].length, 0)
+    })
+  }
+}
+
+if (!global[gracefulQueue]) {
+  publishQueue(global, fs[gracefulQueue]);
+}
+
+module.exports = patch(clone(fs))
+if (process.env.TEST_GRACEFUL_FS_GLOBAL_PATCH && !fs.__patched) {
+    module.exports = patch(fs)
+    fs.__patched = true;
+}
+
+function patch (fs) {
+  // Everything that references the open() function needs to be in here
+  polyfills(fs)
+  fs.gracefulify = patch
+
+  fs.createReadStream = createReadStream
+  fs.createWriteStream = createWriteStream
+  var fs$readFile = fs.readFile
+  fs.readFile = readFile
+  function readFile (path, options, cb) {
+    if (typeof options === 'function')
+      cb = options, options = null
+
+    return go$readFile(path, options, cb)
+
+    function go$readFile (path, options, cb, startTime) {
+      return fs$readFile(path, options, function (err) {
+        if (err && (err.code === 'EMFILE' || err.code === 'ENFILE'))
+          enqueue([go$readFile, [path, options, cb], err, startTime || Date.now(), Date.now()])
+        else {
+          if (typeof cb === 'function')
+            cb.apply(this, arguments)
+        }
+      })
+    }
+  }
+
+  var fs$writeFile = fs.writeFile
+  fs.writeFile = writeFile
+  function writeFile (path, data, options, cb) {
+    if (typeof options === 'function')
+      cb = options, options = null
+
+    return go$writeFile(path, data, options, cb)
+
+    function go$writeFile (path, data, options, cb, startTime) {
+      return fs$writeFile(path, data, options, function (err) {
+        if (err && (err.code === 'EMFILE' || err.code === 'ENFILE'))
+          enqueue([go$writeFile, [path, data, options, cb], err, startTime || Date.now(), Date.now()])
+        else {
+          if (typeof cb === 'function')
+            cb.apply(this, arguments)
+        }
+      })
+    }
+  }
+
+  var fs$appendFile = fs.appendFile
+  if (fs$appendFile)
+    fs.appendFile = appendFile
+  function appendFile (path, data, options, cb) {
+    if (typeof options === 'function')
+      cb = options, options = null
+
+    return go$appendFile(path, data, options, cb)
+
+    function go$appendFile (path, data, options, cb, startTime) {
+      return fs$appendFile(path, data, options, function (err) {
+        if (err && (err.code === 'EMFILE' || err.code === 'ENFILE'))
+          enqueue([go$appendFile, [path, data, options, cb], err, startTime || Date.now(), Date.now()])
+        else {
+          if (typeof cb === 'function')
+            cb.apply(this, arguments)
+        }
+      })
+    }
+  }
+
+  var fs$copyFile = fs.copyFile
+  if (fs$copyFile)
+    fs.copyFile = copyFile
+  function copyFile (src, dest, flags, cb) {
+    if (typeof flags === 'function') {
+      cb = flags
+      flags = 0
+    }
+    return go$copyFile(src, dest, flags, cb)
+
+    function go$copyFile (src, dest, flags, cb, startTime) {
+      return fs$copyFile(src, dest, flags, function (err) {
+        if (err && (err.code === 'EMFILE' || err.code === 'ENFILE'))
+          enqueue([go$copyFile, [src, dest, flags, cb], err, startTime || Date.now(), Date.now()])
+        else {
+          if (typeof cb === 'function')
+            cb.apply(this, arguments)
+        }
+      })
+    }
+  }
+
+  var fs$readdir = fs.readdir
+  fs.readdir = readdir
+  var noReaddirOptionVersions = /^v[0-5]\./
+  function readdir (path, options, cb) {
+    if (typeof options === 'function')
+      cb = options, options = null
+
+    var go$readdir = noReaddirOptionVersions.test(process.version)
+      ? function go$readdir (path, options, cb, startTime) {
+        return fs$readdir(path, fs$readdirCallback(
+          path, options, cb, startTime
+        ))
+      }
+      : function go$readdir (path, options, cb, startTime) {
+        return fs$readdir(path, options, fs$readdirCallback(
+          path, options, cb, startTime
+        ))
+      }
+
+    return go$readdir(path, options, cb)
+
+    function fs$readdirCallback (path, options, cb, startTime) {
+      return function (err, files) {
+        if (err && (err.code === 'EMFILE' || err.code === 'ENFILE'))
+          enqueue([
+            go$readdir,
+            [path, options, cb],
+            err,
+            startTime || Date.now(),
+            Date.now()
+          ])
+        else {
+          if (files && files.sort)
+            files.sort()
+
+          if (typeof cb === 'function')
+            cb.call(this, err, files)
+        }
+      }
+    }
+  }
+
+  if (process.version.substr(0, 4) === 'v0.8') {
+    var legStreams = legacy(fs)
+    ReadStream = legStreams.ReadStream
+    WriteStream = legStreams.WriteStream
+  }
+
+  var fs$ReadStream = fs.ReadStream
+  if (fs$ReadStream) {
+    ReadStream.prototype = Object.create(fs$ReadStream.prototype)
+    ReadStream.prototype.open = ReadStream$open
+  }
+
+  var fs$WriteStream = fs.WriteStream
+  if (fs$WriteStream) {
+    WriteStream.prototype = Object.create(fs$WriteStream.prototype)
+    WriteStream.prototype.open = WriteStream$open
+  }
+
+  Object.defineProperty(fs, 'ReadStream', {
+    get: function () {
+      return ReadStream
+    },
+    set: function (val) {
+      ReadStream = val
+    },
+    enumerable: true,
+    configurable: true
+  })
+  Object.defineProperty(fs, 'WriteStream', {
+    get: function () {
+      return WriteStream
+    },
+    set: function (val) {
+      WriteStream = val
+    },
+    enumerable: true,
+    configurable: true
+  })
+
+  // legacy names
+  var FileReadStream = ReadStream
+  Object.defineProperty(fs, 'FileReadStream', {
+    get: function () {
+      return FileReadStream
+    },
+    set: function (val) {
+      FileReadStream = val
+    },
+    enumerable: true,
+    configurable: true
+  })
+  var FileWriteStream = WriteStream
+  Object.defineProperty(fs, 'FileWriteStream', {
+    get: function () {
+      return FileWriteStream
+    },
+    set: function (val) {
+      FileWriteStream = val
+    },
+    enumerable: true,
+    configurable: true
+  })
+
+  function ReadStream (path, options) {
+    if (this instanceof ReadStream)
+      return fs$ReadStream.apply(this, arguments), this
+    else
+      return ReadStream.apply(Object.create(ReadStream.prototype), arguments)
+  }
+
+  function ReadStream$open () {
+    var that = this
+    open(that.path, that.flags, that.mode, function (err, fd) {
+      if (err) {
+        if (that.autoClose)
+          that.destroy()
+
+        that.emit('error', err)
+      } else {
+        that.fd = fd
+        that.emit('open', fd)
+        that.read()
+      }
+    })
+  }
+
+  function WriteStream (path, options) {
+    if (this instanceof WriteStream)
+      return fs$WriteStream.apply(this, arguments), this
+    else
+      return WriteStream.apply(Object.create(WriteStream.prototype), arguments)
+  }
+
+  function WriteStream$open () {
+    var that = this
+    open(that.path, that.flags, that.mode, function (err, fd) {
+      if (err) {
+        that.destroy()
+        that.emit('error', err)
+      } else {
+        that.fd = fd
+        that.emit('open', fd)
+      }
+    })
+  }
+
+  function createReadStream (path, options) {
+    return new fs.ReadStream(path, options)
+  }
+
+  function createWriteStream (path, options) {
+    return new fs.WriteStream(path, options)
+  }
+
+  var fs$open = fs.open
+  fs.open = open
+  function open (path, flags, mode, cb) {
+    if (typeof mode === 'function')
+      cb = mode, mode = null
+
+    return go$open(path, flags, mode, cb)
+
+    function go$open (path, flags, mode, cb, startTime) {
+      return fs$open(path, flags, mode, function (err, fd) {
+        if (err && (err.code === 'EMFILE' || err.code === 'ENFILE'))
+          enqueue([go$open, [path, flags, mode, cb], err, startTime || Date.now(), Date.now()])
+        else {
+          if (typeof cb === 'function')
+            cb.apply(this, arguments)
+        }
+      })
+    }
+  }
+
+  return fs
+}
+
+function enqueue (elem) {
+  debug('ENQUEUE', elem[0].name, elem[1])
+  fs[gracefulQueue].push(elem)
+  retry()
+}
+
+// keep track of the timeout between retry() calls
+var retryTimer
+
+// reset the startTime and lastTime to now
+// this resets the start of the 60 second overall timeout as well as the
+// delay between attempts so that we'll retry these jobs sooner
+function resetQueue () {
+  var now = Date.now()
+  for (var i = 0; i < fs[gracefulQueue].length; ++i) {
+    // entries that are only a length of 2 are from an older version, don't
+    // bother modifying those since they'll be retried anyway.
+    if (fs[gracefulQueue][i].length > 2) {
+      fs[gracefulQueue][i][3] = now // startTime
+      fs[gracefulQueue][i][4] = now // lastTime
+    }
+  }
+  // call retry to make sure we're actively processing the queue
+  retry()
+}
+
+function retry () {
+  // clear the timer and remove it to help prevent unintended concurrency
+  clearTimeout(retryTimer)
+  retryTimer = undefined
+
+  if (fs[gracefulQueue].length === 0)
+    return
+
+  var elem = fs[gracefulQueue].shift()
+  var fn = elem[0]
+  var args = elem[1]
+  // these items may be unset if they were added by an older graceful-fs
+  var err = elem[2]
+  var startTime = elem[3]
+  var lastTime = elem[4]
+
+  // if we don't have a startTime we have no way of knowing if we've waited
+  // long enough, so go ahead and retry this item now
+  if (startTime === undefined) {
+    debug('RETRY', fn.name, args)
+    fn.apply(null, args)
+  } else if (Date.now() - startTime >= 60000) {
+    // it's been more than 60 seconds total, bail now
+    debug('TIMEOUT', fn.name, args)
+    var cb = args.pop()
+    if (typeof cb === 'function')
+      cb.call(null, err)
+  } else {
+    // the amount of time between the last attempt and right now
+    var sinceAttempt = Date.now() - lastTime
+    // the amount of time between when we first tried, and when we last tried
+    // rounded up to at least 1
+    var sinceStart = Math.max(lastTime - startTime, 1)
+    // backoff. wait longer than the total time we've been retrying, but only
+    // up to a maximum of 100ms
+    var desiredDelay = Math.min(sinceStart * 1.2, 100)
+    // it's been long enough since the last retry, do it again
+    if (sinceAttempt >= desiredDelay) {
+      debug('RETRY', fn.name, args)
+      fn.apply(null, args.concat([startTime]))
+    } else {
+      // if we can't do this job yet, push it to the end of the queue
+      // and let the next iteration check again
+      fs[gracefulQueue].push(elem)
+    }
+  }
+
+  // schedule our next run if one isn't already scheduled
+  if (retryTimer === undefined) {
+    retryTimer = setTimeout(retry, 0)
+  }
+}
diff --git a/server/node_modules/graceful-fs/legacy-streams.js b/server/node_modules/graceful-fs/legacy-streams.js
new file mode 100644
index 0000000..d617b50
--- /dev/null
+++ b/server/node_modules/graceful-fs/legacy-streams.js
@@ -0,0 +1,118 @@
+var Stream = require('stream').Stream
+
+module.exports = legacy
+
+function legacy (fs) {
+  return {
+    ReadStream: ReadStream,
+    WriteStream: WriteStream
+  }
+
+  function ReadStream (path, options) {
+    if (!(this instanceof ReadStream)) return new ReadStream(path, options);
+
+    Stream.call(this);
+
+    var self = this;
+
+    this.path = path;
+    this.fd = null;
+    this.readable = true;
+    this.paused = false;
+
+    this.flags = 'r';
+    this.mode = 438; /*=0666*/
+    this.bufferSize = 64 * 1024;
+
+    options = options || {};
+
+    // Mixin options into this
+    var keys = Object.keys(options);
+    for (var index = 0, length = keys.length; index < length; index++) {
+      var key = keys[index];
+      this[key] = options[key];
+    }
+
+    if (this.encoding) this.setEncoding(this.encoding);
+
+    if (this.start !== undefined) {
+      if ('number' !== typeof this.start) {
+        throw TypeError('start must be a Number');
+      }
+      if (this.end === undefined) {
+        this.end = Infinity;
+      } else if ('number' !== typeof this.end) {
+        throw TypeError('end must be a Number');
+      }
+
+      if (this.start > this.end) {
+        throw new Error('start must be <= end');
+      }
+
+      this.pos = this.start;
+    }
+
+    if (this.fd !== null) {
+      process.nextTick(function() {
+        self._read();
+      });
+      return;
+    }
+
+    fs.open(this.path, this.flags, this.mode, function (err, fd) {
+      if (err) {
+        self.emit('error', err);
+        self.readable = false;
+        return;
+      }
+
+      self.fd = fd;
+      self.emit('open', fd);
+      self._read();
+    })
+  }
+
+  function WriteStream (path, options) {
+    if (!(this instanceof WriteStream)) return new WriteStream(path, options);
+
+    Stream.call(this);
+
+    this.path = path;
+    this.fd = null;
+    this.writable = true;
+
+    this.flags = 'w';
+    this.encoding = 'binary';
+    this.mode = 438; /*=0666*/
+    this.bytesWritten = 0;
+
+    options = options || {};
+
+    // Mixin options into this
+    var keys = Object.keys(options);
+    for (var index = 0, length = keys.length; index < length; index++) {
+      var key = keys[index];
+      this[key] = options[key];
+    }
+
+    if (this.start !== undefined) {
+      if ('number' !== typeof this.start) {
+        throw TypeError('start must be a Number');
+      }
+      if (this.start < 0) {
+        throw new Error('start must be >= zero');
+      }
+
+      this.pos = this.start;
+    }
+
+    this.busy = false;
+    this._queue = [];
+
+    if (this.fd === null) {
+      this._open = fs.open;
+      this._queue.push([this._open, this.path, this.flags, this.mode, undefined]);
+      this.flush();
+    }
+  }
+}
diff --git a/server/node_modules/graceful-fs/package.json b/server/node_modules/graceful-fs/package.json
new file mode 100644
index 0000000..87babf0
--- /dev/null
+++ b/server/node_modules/graceful-fs/package.json
@@ -0,0 +1,53 @@
+{
+  "name": "graceful-fs",
+  "description": "A drop-in replacement for fs, making various improvements.",
+  "version": "4.2.11",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/isaacs/node-graceful-fs"
+  },
+  "main": "graceful-fs.js",
+  "directories": {
+    "test": "test"
+  },
+  "scripts": {
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags",
+    "test": "nyc --silent node test.js | tap -c -",
+    "posttest": "nyc report"
+  },
+  "keywords": [
+    "fs",
+    "module",
+    "reading",
+    "retry",
+    "retries",
+    "queue",
+    "error",
+    "errors",
+    "handling",
+    "EMFILE",
+    "EAGAIN",
+    "EINVAL",
+    "EPERM",
+    "EACCESS"
+  ],
+  "license": "ISC",
+  "devDependencies": {
+    "import-fresh": "^2.0.0",
+    "mkdirp": "^0.5.0",
+    "rimraf": "^2.2.8",
+    "tap": "^16.3.4"
+  },
+  "files": [
+    "fs.js",
+    "graceful-fs.js",
+    "legacy-streams.js",
+    "polyfills.js",
+    "clone.js"
+  ],
+  "tap": {
+    "reporter": "classic"
+  }
+}
diff --git a/server/node_modules/graceful-fs/polyfills.js b/server/node_modules/graceful-fs/polyfills.js
new file mode 100644
index 0000000..453f1a9
--- /dev/null
+++ b/server/node_modules/graceful-fs/polyfills.js
@@ -0,0 +1,355 @@
+var constants = require('constants')
+
+var origCwd = process.cwd
+var cwd = null
+
+var platform = process.env.GRACEFUL_FS_PLATFORM || process.platform
+
+process.cwd = function() {
+  if (!cwd)
+    cwd = origCwd.call(process)
+  return cwd
+}
+try {
+  process.cwd()
+} catch (er) {}
+
+// This check is needed until node.js 12 is required
+if (typeof process.chdir === 'function') {
+  var chdir = process.chdir
+  process.chdir = function (d) {
+    cwd = null
+    chdir.call(process, d)
+  }
+  if (Object.setPrototypeOf) Object.setPrototypeOf(process.chdir, chdir)
+}
+
+module.exports = patch
+
+function patch (fs) {
+  // (re-)implement some things that are known busted or missing.
+
+  // lchmod, broken prior to 0.6.2
+  // back-port the fix here.
+  if (constants.hasOwnProperty('O_SYMLINK') &&
+      process.version.match(/^v0\.6\.[0-2]|^v0\.5\./)) {
+    patchLchmod(fs)
+  }
+
+  // lutimes implementation, or no-op
+  if (!fs.lutimes) {
+    patchLutimes(fs)
+  }
+
+  // https://github.com/isaacs/node-graceful-fs/issues/4
+  // Chown should not fail on einval or eperm if non-root.
+  // It should not fail on enosys ever, as this just indicates
+  // that a fs doesn't support the intended operation.
+
+  fs.chown = chownFix(fs.chown)
+  fs.fchown = chownFix(fs.fchown)
+  fs.lchown = chownFix(fs.lchown)
+
+  fs.chmod = chmodFix(fs.chmod)
+  fs.fchmod = chmodFix(fs.fchmod)
+  fs.lchmod = chmodFix(fs.lchmod)
+
+  fs.chownSync = chownFixSync(fs.chownSync)
+  fs.fchownSync = chownFixSync(fs.fchownSync)
+  fs.lchownSync = chownFixSync(fs.lchownSync)
+
+  fs.chmodSync = chmodFixSync(fs.chmodSync)
+  fs.fchmodSync = chmodFixSync(fs.fchmodSync)
+  fs.lchmodSync = chmodFixSync(fs.lchmodSync)
+
+  fs.stat = statFix(fs.stat)
+  fs.fstat = statFix(fs.fstat)
+  fs.lstat = statFix(fs.lstat)
+
+  fs.statSync = statFixSync(fs.statSync)
+  fs.fstatSync = statFixSync(fs.fstatSync)
+  fs.lstatSync = statFixSync(fs.lstatSync)
+
+  // if lchmod/lchown do not exist, then make them no-ops
+  if (fs.chmod && !fs.lchmod) {
+    fs.lchmod = function (path, mode, cb) {
+      if (cb) process.nextTick(cb)
+    }
+    fs.lchmodSync = function () {}
+  }
+  if (fs.chown && !fs.lchown) {
+    fs.lchown = function (path, uid, gid, cb) {
+      if (cb) process.nextTick(cb)
+    }
+    fs.lchownSync = function () {}
+  }
+
+  // on Windows, A/V software can lock the directory, causing this
+  // to fail with an EACCES or EPERM if the directory contains newly
+  // created files.  Try again on failure, for up to 60 seconds.
+
+  // Set the timeout this long because some Windows Anti-Virus, such as Parity
+  // bit9, may lock files for up to a minute, causing npm package install
+  // failures. Also, take care to yield the scheduler. Windows scheduling gives
+  // CPU to a busy looping process, which can cause the program causing the lock
+  // contention to be starved of CPU by node, so the contention doesn't resolve.
+  if (platform === "win32") {
+    fs.rename = typeof fs.rename !== 'function' ? fs.rename
+    : (function (fs$rename) {
+      function rename (from, to, cb) {
+        var start = Date.now()
+        var backoff = 0;
+        fs$rename(from, to, function CB (er) {
+          if (er
+              && (er.code === "EACCES" || er.code === "EPERM" || er.code === "EBUSY")
+              && Date.now() - start < 60000) {
+            setTimeout(function() {
+              fs.stat(to, function (stater, st) {
+                if (stater && stater.code === "ENOENT")
+                  fs$rename(from, to, CB);
+                else
+                  cb(er)
+              })
+            }, backoff)
+            if (backoff < 100)
+              backoff += 10;
+            return;
+          }
+          if (cb) cb(er)
+        })
+      }
+      if (Object.setPrototypeOf) Object.setPrototypeOf(rename, fs$rename)
+      return rename
+    })(fs.rename)
+  }
+
+  // if read() returns EAGAIN, then just try it again.
+  fs.read = typeof fs.read !== 'function' ? fs.read
+  : (function (fs$read) {
+    function read (fd, buffer, offset, length, position, callback_) {
+      var callback
+      if (callback_ && typeof callback_ === 'function') {
+        var eagCounter = 0
+        callback = function (er, _, __) {
+          if (er && er.code === 'EAGAIN' && eagCounter < 10) {
+            eagCounter ++
+            return fs$read.call(fs, fd, buffer, offset, length, position, callback)
+          }
+          callback_.apply(this, arguments)
+        }
+      }
+      return fs$read.call(fs, fd, buffer, offset, length, position, callback)
+    }
+
+    // This ensures `util.promisify` works as it does for native `fs.read`.
+    if (Object.setPrototypeOf) Object.setPrototypeOf(read, fs$read)
+    return read
+  })(fs.read)
+
+  fs.readSync = typeof fs.readSync !== 'function' ? fs.readSync
+  : (function (fs$readSync) { return function (fd, buffer, offset, length, position) {
+    var eagCounter = 0
+    while (true) {
+      try {
+        return fs$readSync.call(fs, fd, buffer, offset, length, position)
+      } catch (er) {
+        if (er.code === 'EAGAIN' && eagCounter < 10) {
+          eagCounter ++
+          continue
+        }
+        throw er
+      }
+    }
+  }})(fs.readSync)
+
+  function patchLchmod (fs) {
+    fs.lchmod = function (path, mode, callback) {
+      fs.open( path
+             , constants.O_WRONLY | constants.O_SYMLINK
+             , mode
+             , function (err, fd) {
+        if (err) {
+          if (callback) callback(err)
+          return
+        }
+        // prefer to return the chmod error, if one occurs,
+        // but still try to close, and report closing errors if they occur.
+        fs.fchmod(fd, mode, function (err) {
+          fs.close(fd, function(err2) {
+            if (callback) callback(err || err2)
+          })
+        })
+      })
+    }
+
+    fs.lchmodSync = function (path, mode) {
+      var fd = fs.openSync(path, constants.O_WRONLY | constants.O_SYMLINK, mode)
+
+      // prefer to return the chmod error, if one occurs,
+      // but still try to close, and report closing errors if they occur.
+      var threw = true
+      var ret
+      try {
+        ret = fs.fchmodSync(fd, mode)
+        threw = false
+      } finally {
+        if (threw) {
+          try {
+            fs.closeSync(fd)
+          } catch (er) {}
+        } else {
+          fs.closeSync(fd)
+        }
+      }
+      return ret
+    }
+  }
+
+  function patchLutimes (fs) {
+    if (constants.hasOwnProperty("O_SYMLINK") && fs.futimes) {
+      fs.lutimes = function (path, at, mt, cb) {
+        fs.open(path, constants.O_SYMLINK, function (er, fd) {
+          if (er) {
+            if (cb) cb(er)
+            return
+          }
+          fs.futimes(fd, at, mt, function (er) {
+            fs.close(fd, function (er2) {
+              if (cb) cb(er || er2)
+            })
+          })
+        })
+      }
+
+      fs.lutimesSync = function (path, at, mt) {
+        var fd = fs.openSync(path, constants.O_SYMLINK)
+        var ret
+        var threw = true
+        try {
+          ret = fs.futimesSync(fd, at, mt)
+          threw = false
+        } finally {
+          if (threw) {
+            try {
+              fs.closeSync(fd)
+            } catch (er) {}
+          } else {
+            fs.closeSync(fd)
+          }
+        }
+        return ret
+      }
+
+    } else if (fs.futimes) {
+      fs.lutimes = function (_a, _b, _c, cb) { if (cb) process.nextTick(cb) }
+      fs.lutimesSync = function () {}
+    }
+  }
+
+  function chmodFix (orig) {
+    if (!orig) return orig
+    return function (target, mode, cb) {
+      return orig.call(fs, target, mode, function (er) {
+        if (chownErOk(er)) er = null
+        if (cb) cb.apply(this, arguments)
+      })
+    }
+  }
+
+  function chmodFixSync (orig) {
+    if (!orig) return orig
+    return function (target, mode) {
+      try {
+        return orig.call(fs, target, mode)
+      } catch (er) {
+        if (!chownErOk(er)) throw er
+      }
+    }
+  }
+
+
+  function chownFix (orig) {
+    if (!orig) return orig
+    return function (target, uid, gid, cb) {
+      return orig.call(fs, target, uid, gid, function (er) {
+        if (chownErOk(er)) er = null
+        if (cb) cb.apply(this, arguments)
+      })
+    }
+  }
+
+  function chownFixSync (orig) {
+    if (!orig) return orig
+    return function (target, uid, gid) {
+      try {
+        return orig.call(fs, target, uid, gid)
+      } catch (er) {
+        if (!chownErOk(er)) throw er
+      }
+    }
+  }
+
+  function statFix (orig) {
+    if (!orig) return orig
+    // Older versions of Node erroneously returned signed integers for
+    // uid + gid.
+    return function (target, options, cb) {
+      if (typeof options === 'function') {
+        cb = options
+        options = null
+      }
+      function callback (er, stats) {
+        if (stats) {
+          if (stats.uid < 0) stats.uid += 0x100000000
+          if (stats.gid < 0) stats.gid += 0x100000000
+        }
+        if (cb) cb.apply(this, arguments)
+      }
+      return options ? orig.call(fs, target, options, callback)
+        : orig.call(fs, target, callback)
+    }
+  }
+
+  function statFixSync (orig) {
+    if (!orig) return orig
+    // Older versions of Node erroneously returned signed integers for
+    // uid + gid.
+    return function (target, options) {
+      var stats = options ? orig.call(fs, target, options)
+        : orig.call(fs, target)
+      if (stats) {
+        if (stats.uid < 0) stats.uid += 0x100000000
+        if (stats.gid < 0) stats.gid += 0x100000000
+      }
+      return stats;
+    }
+  }
+
+  // ENOSYS means that the fs doesn't support the op. Just ignore
+  // that, because it doesn't matter.
+  //
+  // if there's no getuid, or if getuid() is something other
+  // than 0, and the error is EINVAL or EPERM, then just ignore
+  // it.
+  //
+  // This specific case is a silent failure in cp, install, tar,
+  // and most other unix tools that manage permissions.
+  //
+  // When running as root, or if other types of errors are
+  // encountered, then it's strict.
+  function chownErOk (er) {
+    if (!er)
+      return true
+
+    if (er.code === "ENOSYS")
+      return true
+
+    var nonroot = !process.getuid || process.getuid() !== 0
+    if (nonroot) {
+      if (er.code === "EINVAL" || er.code === "EPERM")
+        return true
+    }
+
+    return false
+  }
+}
diff --git a/server/node_modules/has-symbols/.eslintrc b/server/node_modules/has-symbols/.eslintrc
new file mode 100644
index 0000000..2d9a66a
--- /dev/null
+++ b/server/node_modules/has-symbols/.eslintrc
@@ -0,0 +1,11 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"max-statements-per-line": [2, { "max": 2 }],
+		"no-magic-numbers": 0,
+		"multiline-comment-style": 0,
+	}
+}
diff --git a/server/node_modules/has-symbols/.github/FUNDING.yml b/server/node_modules/has-symbols/.github/FUNDING.yml
new file mode 100644
index 0000000..04cf87e
--- /dev/null
+++ b/server/node_modules/has-symbols/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/has-symbols
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/has-symbols/.nycrc b/server/node_modules/has-symbols/.nycrc
new file mode 100644
index 0000000..bdd626c
--- /dev/null
+++ b/server/node_modules/has-symbols/.nycrc
@@ -0,0 +1,9 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/has-symbols/CHANGELOG.md b/server/node_modules/has-symbols/CHANGELOG.md
new file mode 100644
index 0000000..cc3cf83
--- /dev/null
+++ b/server/node_modules/has-symbols/CHANGELOG.md
@@ -0,0 +1,91 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.1.0](https://github.com/inspect-js/has-symbols/compare/v1.0.3...v1.1.0) - 2024-12-02
+
+### Commits
+
+- [actions] update workflows [`548c0bf`](https://github.com/inspect-js/has-symbols/commit/548c0bf8c9b1235458df7a1c0490b0064647a282)
+- [actions] further shard; update action deps [`bec56bb`](https://github.com/inspect-js/has-symbols/commit/bec56bb0fb44b43a786686b944875a3175cf3ff3)
+- [meta] use `npmignore` to autogenerate an npmignore file [`ac81032`](https://github.com/inspect-js/has-symbols/commit/ac81032809157e0a079e5264e9ce9b6f1275777e)
+- [New] add types [`6469cbf`](https://github.com/inspect-js/has-symbols/commit/6469cbff1866cfe367b2b3d181d9296ec14b2a3d)
+- [actions] update rebase action to use reusable workflow [`9c9d4d0`](https://github.com/inspect-js/has-symbols/commit/9c9d4d0d8938e4b267acdf8e421f4e92d1716d72)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `tape` [`adb5887`](https://github.com/inspect-js/has-symbols/commit/adb5887ca9444849b08beb5caaa9e1d42320cdfb)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud`, `tape` [`13ec198`](https://github.com/inspect-js/has-symbols/commit/13ec198ec80f1993a87710af1606a1970b22c7cb)
+- [Dev Deps] update `auto-changelog`, `core-js`, `tape` [`941be52`](https://github.com/inspect-js/has-symbols/commit/941be5248387cab1da72509b22acf3fdb223f057)
+- [Tests] replace `aud` with `npm audit` [`74f49e9`](https://github.com/inspect-js/has-symbols/commit/74f49e9a9d17a443020784234a1c53ce765b3559)
+- [Dev Deps] update `npmignore` [`9c0ac04`](https://github.com/inspect-js/has-symbols/commit/9c0ac0452a834f4c2a4b54044f2d6a89f17e9a70)
+- [Dev Deps] add missing peer dep [`52337a5`](https://github.com/inspect-js/has-symbols/commit/52337a5621cced61f846f2afdab7707a8132cc12)
+
+## [v1.0.3](https://github.com/inspect-js/has-symbols/compare/v1.0.2...v1.0.3) - 2022-03-01
+
+### Commits
+
+- [actions] use `node/install` instead of `node/run`; use `codecov` action [`518b28f`](https://github.com/inspect-js/has-symbols/commit/518b28f6c5a516cbccae30794e40aa9f738b1693)
+- [meta] add `bugs` and `homepage` fields; reorder package.json [`c480b13`](https://github.com/inspect-js/has-symbols/commit/c480b13fd6802b557e1cef9749872cb5fdeef744)
+- [actions] reuse common workflows [`01d0ee0`](https://github.com/inspect-js/has-symbols/commit/01d0ee0a8d97c0947f5edb73eb722027a77b2b07)
+- [actions] update codecov uploader [`6424ebe`](https://github.com/inspect-js/has-symbols/commit/6424ebe86b2c9c7c3d2e9bd4413a4e4f168cb275)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `auto-changelog`, `tape` [`dfa7e7f`](https://github.com/inspect-js/has-symbols/commit/dfa7e7ff38b594645d8c8222aab895157fa7e282)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `safe-publish-latest`, `tape` [`0c8d436`](https://github.com/inspect-js/has-symbols/commit/0c8d43685c45189cea9018191d4fd7eca91c9d02)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `tape` [`9026554`](https://github.com/inspect-js/has-symbols/commit/902655442a1bf88e72b42345494ef0c60f5d36ab)
+- [readme] add actions and codecov badges [`eaa9682`](https://github.com/inspect-js/has-symbols/commit/eaa9682f990f481d3acf7a1c7600bec36f7b3adc)
+- [Dev Deps] update `eslint`, `tape` [`bc7a3ba`](https://github.com/inspect-js/has-symbols/commit/bc7a3ba46f27b7743f8a2579732d59d1b9ac791e)
+- [Dev Deps] update `eslint`, `auto-changelog` [`0ace00a`](https://github.com/inspect-js/has-symbols/commit/0ace00af08a88cdd1e6ce0d60357d941c60c2d9f)
+- [meta] use `prepublishOnly` script for npm 7+ [`093f72b`](https://github.com/inspect-js/has-symbols/commit/093f72bc2b0ed00c781f444922a5034257bf561d)
+- [Tests] test on all 16 minors [`9b80d3d`](https://github.com/inspect-js/has-symbols/commit/9b80d3d9102529f04c20ec5b1fcc6e38426c6b03)
+
+## [v1.0.2](https://github.com/inspect-js/has-symbols/compare/v1.0.1...v1.0.2) - 2021-02-27
+
+### Fixed
+
+- [Fix] use a universal way to get the original Symbol [`#11`](https://github.com/inspect-js/has-symbols/issues/11)
+
+### Commits
+
+- [Tests] migrate tests to Github Actions [`90ae798`](https://github.com/inspect-js/has-symbols/commit/90ae79820bdfe7bc703d67f5f3c5e205f98556d3)
+- [meta] do not publish github action workflow files [`29e60a1`](https://github.com/inspect-js/has-symbols/commit/29e60a1b7c25c7f1acf7acff4a9320d0d10c49b4)
+- [Tests] run `nyc` on all tests [`8476b91`](https://github.com/inspect-js/has-symbols/commit/8476b915650d360915abe2522505abf4b0e8f0ae)
+- [readme] fix repo URLs, remove defunct badges [`126288e`](https://github.com/inspect-js/has-symbols/commit/126288ecc1797c0a40247a6b78bcb2e0bc5d7036)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `auto-changelog`, `core-js`, `get-own-property-symbols` [`d84bdfa`](https://github.com/inspect-js/has-symbols/commit/d84bdfa48ac5188abbb4904b42614cd6c030940a)
+- [Tests] fix linting errors [`0df3070`](https://github.com/inspect-js/has-symbols/commit/0df3070b981b6c9f2ee530c09189a7f5c6def839)
+- [actions] add "Allow Edits" workflow [`1e6bc29`](https://github.com/inspect-js/has-symbols/commit/1e6bc29b188f32b9648657b07eda08504be5aa9c)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `tape` [`36cea2a`](https://github.com/inspect-js/has-symbols/commit/36cea2addd4e6ec435f35a2656b4e9ef82498e9b)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `tape` [`1278338`](https://github.com/inspect-js/has-symbols/commit/127833801865fbc2cc8979beb9ca869c7bfe8222)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `tape` [`1493254`](https://github.com/inspect-js/has-symbols/commit/1493254eda13db5fb8fc5e4a3e8324b3d196029d)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `core-js` [`b090bf2`](https://github.com/inspect-js/has-symbols/commit/b090bf214d3679a30edc1e2d729d466ab5183e1d)
+- [actions] switch Automatic Rebase workflow to `pull_request_target` event [`4addb7a`](https://github.com/inspect-js/has-symbols/commit/4addb7ab4dc73f927ae99928d68817554fc21dc0)
+- [Dev Deps] update `auto-changelog`, `tape` [`81d0baf`](https://github.com/inspect-js/has-symbols/commit/81d0baf3816096a89a8558e8043895f7a7d10d8b)
+- [Dev Deps] update `auto-changelog`; add `aud` [`1a4e561`](https://github.com/inspect-js/has-symbols/commit/1a4e5612c25d91c3a03d509721d02630bc4fe3da)
+- [readme] remove unused testling URLs [`3000941`](https://github.com/inspect-js/has-symbols/commit/3000941f958046e923ed8152edb1ef4a599e6fcc)
+- [Tests] only audit prod deps [`692e974`](https://github.com/inspect-js/has-symbols/commit/692e9743c912410e9440207631a643a34b4741a1)
+- [Dev Deps] update `@ljharb/eslint-config` [`51c946c`](https://github.com/inspect-js/has-symbols/commit/51c946c7f6baa793ec5390bb5a45cdce16b4ba76)
+
+## [v1.0.1](https://github.com/inspect-js/has-symbols/compare/v1.0.0...v1.0.1) - 2019-11-16
+
+### Commits
+
+- [Tests] use shared travis-ci configs [`ce396c9`](https://github.com/inspect-js/has-symbols/commit/ce396c9419ff11c43d0da5d05cdbb79f7fb42229)
+- [Tests] up to `node` `v12.4`, `v11.15`, `v10.15`, `v9.11`, `v8.15`, `v7.10`, `v6.17`, `v4.9`; use `nvm install-latest-npm` [`0690732`](https://github.com/inspect-js/has-symbols/commit/0690732801f47ab429f39ba1962f522d5c462d6b)
+- [meta] add `auto-changelog` [`2163d0b`](https://github.com/inspect-js/has-symbols/commit/2163d0b7f36343076b8f947cd1667dd1750f26fc)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `core-js`, `safe-publish-latest`, `tape` [`8e0951f`](https://github.com/inspect-js/has-symbols/commit/8e0951f1a7a2e52068222b7bb73511761e6e4d9c)
+- [actions] add automatic rebasing / merge commit blocking [`b09cdb7`](https://github.com/inspect-js/has-symbols/commit/b09cdb7cd7ee39e7a769878f56e2d6066f5ccd1d)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `safe-publish-latest`, `core-js`, `get-own-property-symbols`, `tape` [`1dd42cd`](https://github.com/inspect-js/has-symbols/commit/1dd42cd86183ed0c50f99b1062345c458babca91)
+- [meta] create FUNDING.yml [`aa57a17`](https://github.com/inspect-js/has-symbols/commit/aa57a17b19708906d1927f821ea8e73394d84ca4)
+- Only apps should have lockfiles [`a2d8bea`](https://github.com/inspect-js/has-symbols/commit/a2d8bea23a97d15c09eaf60f5b107fcf9a4d57aa)
+- [Tests] use `npx aud` instead of `nsp` or `npm audit` with hoops [`9e96cb7`](https://github.com/inspect-js/has-symbols/commit/9e96cb783746cbed0c10ef78e599a8eaa7ebe193)
+- [meta] add `funding` field [`a0b32cf`](https://github.com/inspect-js/has-symbols/commit/a0b32cf68e803f963c1639b6d47b0a9d6440bab0)
+- [Dev Deps] update `safe-publish-latest` [`cb9f0a5`](https://github.com/inspect-js/has-symbols/commit/cb9f0a521a3a1790f1064d437edd33bb6c3d6af0)
+
+## v1.0.0 - 2016-09-19
+
+### Commits
+
+- Tests. [`ecb6eb9`](https://github.com/inspect-js/has-symbols/commit/ecb6eb934e4883137f3f93b965ba5e0a98df430d)
+- package.json [`88a337c`](https://github.com/inspect-js/has-symbols/commit/88a337cee0864a0da35f5d19e69ff0ef0150e46a)
+- Initial commit [`42e1e55`](https://github.com/inspect-js/has-symbols/commit/42e1e5502536a2b8ac529c9443984acd14836b1c)
+- Initial implementation. [`33f5cc6`](https://github.com/inspect-js/has-symbols/commit/33f5cc6cdff86e2194b081ee842bfdc63caf43fb)
+- read me [`01f1170`](https://github.com/inspect-js/has-symbols/commit/01f1170188ff7cb1558aa297f6ba5b516c6d7b0c)
diff --git a/server/node_modules/has-symbols/LICENSE b/server/node_modules/has-symbols/LICENSE
new file mode 100644
index 0000000..df31cbf
--- /dev/null
+++ b/server/node_modules/has-symbols/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2016 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/has-symbols/README.md b/server/node_modules/has-symbols/README.md
new file mode 100644
index 0000000..33905f0
--- /dev/null
+++ b/server/node_modules/has-symbols/README.md
@@ -0,0 +1,46 @@
+# has-symbols <sup>[![Version Badge][2]][1]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![dependency status][5]][6]
+[![dev dependency status][7]][8]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][11]][1]
+
+Determine if the JS environment has Symbol support. Supports spec, or shams.
+
+## Example
+
+```js
+var hasSymbols = require('has-symbols');
+
+hasSymbols() === true; // if the environment has native Symbol support. Not polyfillable, not forgeable.
+
+var hasSymbolsKinda = require('has-symbols/shams');
+hasSymbolsKinda() === true; // if the environment has a Symbol sham that mostly follows the spec.
+```
+
+## Supported Symbol shams
+ - get-own-property-symbols [npm](https://www.npmjs.com/package/get-own-property-symbols) | [github](https://github.com/WebReflection/get-own-property-symbols)
+ - core-js [npm](https://www.npmjs.com/package/core-js) | [github](https://github.com/zloirock/core-js)
+
+## Tests
+Simply clone the repo, `npm install`, and run `npm test`
+
+[1]: https://npmjs.org/package/has-symbols
+[2]: https://versionbadg.es/inspect-js/has-symbols.svg
+[5]: https://david-dm.org/inspect-js/has-symbols.svg
+[6]: https://david-dm.org/inspect-js/has-symbols
+[7]: https://david-dm.org/inspect-js/has-symbols/dev-status.svg
+[8]: https://david-dm.org/inspect-js/has-symbols#info=devDependencies
+[11]: https://nodei.co/npm/has-symbols.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/has-symbols.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/has-symbols.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=has-symbols
+[codecov-image]: https://codecov.io/gh/inspect-js/has-symbols/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/inspect-js/has-symbols/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/inspect-js/has-symbols
+[actions-url]: https://github.com/inspect-js/has-symbols/actions
diff --git a/server/node_modules/has-symbols/index.d.ts b/server/node_modules/has-symbols/index.d.ts
new file mode 100644
index 0000000..9b98595
--- /dev/null
+++ b/server/node_modules/has-symbols/index.d.ts
@@ -0,0 +1,3 @@
+declare function hasNativeSymbols(): boolean;
+
+export = hasNativeSymbols;
\ No newline at end of file
diff --git a/server/node_modules/has-symbols/index.js b/server/node_modules/has-symbols/index.js
new file mode 100644
index 0000000..fa65265
--- /dev/null
+++ b/server/node_modules/has-symbols/index.js
@@ -0,0 +1,14 @@
+'use strict';
+
+var origSymbol = typeof Symbol !== 'undefined' && Symbol;
+var hasSymbolSham = require('./shams');
+
+/** @type {import('.')} */
+module.exports = function hasNativeSymbols() {
+	if (typeof origSymbol !== 'function') { return false; }
+	if (typeof Symbol !== 'function') { return false; }
+	if (typeof origSymbol('foo') !== 'symbol') { return false; }
+	if (typeof Symbol('bar') !== 'symbol') { return false; }
+
+	return hasSymbolSham();
+};
diff --git a/server/node_modules/has-symbols/package.json b/server/node_modules/has-symbols/package.json
new file mode 100644
index 0000000..d835e20
--- /dev/null
+++ b/server/node_modules/has-symbols/package.json
@@ -0,0 +1,111 @@
+{
+	"name": "has-symbols",
+	"version": "1.1.0",
+	"description": "Determine if the JS environment has Symbol support. Supports spec, or shams.",
+	"main": "index.js",
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"pretest": "npm run --silent lint",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>=10.2' audit --production",
+		"tests-only": "npm run test:stock && npm run test:shams",
+		"test:stock": "nyc node test",
+		"test:staging": "nyc node --harmony --es-staging test",
+		"test:shams": "npm run --silent test:shams:getownpropertysymbols && npm run --silent test:shams:corejs",
+		"test:shams:corejs": "nyc node test/shams/core-js.js",
+		"test:shams:getownpropertysymbols": "nyc node test/shams/get-own-property-symbols.js",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc -p . && attw -P",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git://github.com/inspect-js/has-symbols.git"
+	},
+	"keywords": [
+		"Symbol",
+		"symbols",
+		"typeof",
+		"sham",
+		"polyfill",
+		"native",
+		"core-js",
+		"ES6"
+	],
+	"author": {
+		"name": "Jordan Harband",
+		"email": "ljharb@gmail.com",
+		"url": "http://ljharb.codes"
+	},
+	"contributors": [
+		{
+			"name": "Jordan Harband",
+			"email": "ljharb@gmail.com",
+			"url": "http://ljharb.codes"
+		}
+	],
+	"funding": {
+		"url": "https://github.com/sponsors/ljharb"
+	},
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/has-symbols/issues"
+	},
+	"homepage": "https://github.com/ljharb/has-symbols#readme",
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.0",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.0",
+		"@types/core-js": "^2.5.8",
+		"@types/tape": "^5.6.5",
+		"auto-changelog": "^2.5.0",
+		"core-js": "^2.6.12",
+		"encoding": "^0.1.13",
+		"eslint": "=8.8.0",
+		"get-own-property-symbols": "^0.9.5",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"testling": {
+		"files": "test/index.js",
+		"browsers": [
+			"iexplore/6.0..latest",
+			"firefox/3.0..6.0",
+			"firefox/15.0..latest",
+			"firefox/nightly",
+			"chrome/4.0..10.0",
+			"chrome/20.0..latest",
+			"chrome/canary",
+			"opera/10.0..latest",
+			"opera/next",
+			"safari/4.0..latest",
+			"ipad/6.0..latest",
+			"iphone/6.0..latest",
+			"android-browser/4.2"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows",
+			"types"
+		]
+	}
+}
diff --git a/server/node_modules/has-symbols/shams.d.ts b/server/node_modules/has-symbols/shams.d.ts
new file mode 100644
index 0000000..8d0bf24
--- /dev/null
+++ b/server/node_modules/has-symbols/shams.d.ts
@@ -0,0 +1,3 @@
+declare function hasSymbolShams(): boolean;
+
+export = hasSymbolShams;
\ No newline at end of file
diff --git a/server/node_modules/has-symbols/shams.js b/server/node_modules/has-symbols/shams.js
new file mode 100644
index 0000000..f97b474
--- /dev/null
+++ b/server/node_modules/has-symbols/shams.js
@@ -0,0 +1,45 @@
+'use strict';
+
+/** @type {import('./shams')} */
+/* eslint complexity: [2, 18], max-statements: [2, 33] */
+module.exports = function hasSymbols() {
+	if (typeof Symbol !== 'function' || typeof Object.getOwnPropertySymbols !== 'function') { return false; }
+	if (typeof Symbol.iterator === 'symbol') { return true; }
+
+	/** @type {{ [k in symbol]?: unknown }} */
+	var obj = {};
+	var sym = Symbol('test');
+	var symObj = Object(sym);
+	if (typeof sym === 'string') { return false; }
+
+	if (Object.prototype.toString.call(sym) !== '[object Symbol]') { return false; }
+	if (Object.prototype.toString.call(symObj) !== '[object Symbol]') { return false; }
+
+	// temp disabled per https://github.com/ljharb/object.assign/issues/17
+	// if (sym instanceof Symbol) { return false; }
+	// temp disabled per https://github.com/WebReflection/get-own-property-symbols/issues/4
+	// if (!(symObj instanceof Symbol)) { return false; }
+
+	// if (typeof Symbol.prototype.toString !== 'function') { return false; }
+	// if (String(sym) !== Symbol.prototype.toString.call(sym)) { return false; }
+
+	var symVal = 42;
+	obj[sym] = symVal;
+	for (var _ in obj) { return false; } // eslint-disable-line no-restricted-syntax, no-unreachable-loop
+	if (typeof Object.keys === 'function' && Object.keys(obj).length !== 0) { return false; }
+
+	if (typeof Object.getOwnPropertyNames === 'function' && Object.getOwnPropertyNames(obj).length !== 0) { return false; }
+
+	var syms = Object.getOwnPropertySymbols(obj);
+	if (syms.length !== 1 || syms[0] !== sym) { return false; }
+
+	if (!Object.prototype.propertyIsEnumerable.call(obj, sym)) { return false; }
+
+	if (typeof Object.getOwnPropertyDescriptor === 'function') {
+		// eslint-disable-next-line no-extra-parens
+		var descriptor = /** @type {PropertyDescriptor} */ (Object.getOwnPropertyDescriptor(obj, sym));
+		if (descriptor.value !== symVal || descriptor.enumerable !== true) { return false; }
+	}
+
+	return true;
+};
diff --git a/server/node_modules/has-symbols/test/index.js b/server/node_modules/has-symbols/test/index.js
new file mode 100644
index 0000000..352129c
--- /dev/null
+++ b/server/node_modules/has-symbols/test/index.js
@@ -0,0 +1,22 @@
+'use strict';
+
+var test = require('tape');
+var hasSymbols = require('../');
+var runSymbolTests = require('./tests');
+
+test('interface', function (t) {
+	t.equal(typeof hasSymbols, 'function', 'is a function');
+	t.equal(typeof hasSymbols(), 'boolean', 'returns a boolean');
+	t.end();
+});
+
+test('Symbols are supported', { skip: !hasSymbols() }, function (t) {
+	runSymbolTests(t);
+	t.end();
+});
+
+test('Symbols are not supported', { skip: hasSymbols() }, function (t) {
+	t.equal(typeof Symbol, 'undefined', 'global Symbol is undefined');
+	t.equal(typeof Object.getOwnPropertySymbols, 'undefined', 'Object.getOwnPropertySymbols does not exist');
+	t.end();
+});
diff --git a/server/node_modules/has-symbols/test/shams/core-js.js b/server/node_modules/has-symbols/test/shams/core-js.js
new file mode 100644
index 0000000..1a29024
--- /dev/null
+++ b/server/node_modules/has-symbols/test/shams/core-js.js
@@ -0,0 +1,29 @@
+'use strict';
+
+var test = require('tape');
+
+if (typeof Symbol === 'function' && typeof Symbol() === 'symbol') {
+	test('has native Symbol support', function (t) {
+		t.equal(typeof Symbol, 'function');
+		t.equal(typeof Symbol(), 'symbol');
+		t.end();
+	});
+	// @ts-expect-error TS is stupid and doesn't know about top level return
+	return;
+}
+
+var hasSymbols = require('../../shams');
+
+test('polyfilled Symbols', function (t) {
+	/* eslint-disable global-require */
+	t.equal(hasSymbols(), false, 'hasSymbols is false before polyfilling');
+	require('core-js/fn/symbol');
+	require('core-js/fn/symbol/to-string-tag');
+
+	require('../tests')(t);
+
+	var hasSymbolsAfter = hasSymbols();
+	t.equal(hasSymbolsAfter, true, 'hasSymbols is true after polyfilling');
+	/* eslint-enable global-require */
+	t.end();
+});
diff --git a/server/node_modules/has-symbols/test/shams/get-own-property-symbols.js b/server/node_modules/has-symbols/test/shams/get-own-property-symbols.js
new file mode 100644
index 0000000..e0296f8
--- /dev/null
+++ b/server/node_modules/has-symbols/test/shams/get-own-property-symbols.js
@@ -0,0 +1,29 @@
+'use strict';
+
+var test = require('tape');
+
+if (typeof Symbol === 'function' && typeof Symbol() === 'symbol') {
+	test('has native Symbol support', function (t) {
+		t.equal(typeof Symbol, 'function');
+		t.equal(typeof Symbol(), 'symbol');
+		t.end();
+	});
+	// @ts-expect-error TS is stupid and doesn't know about top level return
+	return;
+}
+
+var hasSymbols = require('../../shams');
+
+test('polyfilled Symbols', function (t) {
+	/* eslint-disable global-require */
+	t.equal(hasSymbols(), false, 'hasSymbols is false before polyfilling');
+
+	require('get-own-property-symbols');
+
+	require('../tests')(t);
+
+	var hasSymbolsAfter = hasSymbols();
+	t.equal(hasSymbolsAfter, true, 'hasSymbols is true after polyfilling');
+	/* eslint-enable global-require */
+	t.end();
+});
diff --git a/server/node_modules/has-symbols/test/tests.js b/server/node_modules/has-symbols/test/tests.js
new file mode 100644
index 0000000..66a2cb8
--- /dev/null
+++ b/server/node_modules/has-symbols/test/tests.js
@@ -0,0 +1,58 @@
+'use strict';
+
+/** @type {(t: import('tape').Test) => false | void} */
+// eslint-disable-next-line consistent-return
+module.exports = function runSymbolTests(t) {
+	t.equal(typeof Symbol, 'function', 'global Symbol is a function');
+
+	if (typeof Symbol !== 'function') { return false; }
+
+	t.notEqual(Symbol(), Symbol(), 'two symbols are not equal');
+
+	/*
+	t.equal(
+		Symbol.prototype.toString.call(Symbol('foo')),
+		Symbol.prototype.toString.call(Symbol('foo')),
+		'two symbols with the same description stringify the same'
+	);
+	*/
+
+	/*
+	var foo = Symbol('foo');
+
+	t.notEqual(
+		String(foo),
+		String(Symbol('bar')),
+		'two symbols with different descriptions do not stringify the same'
+	);
+	*/
+
+	t.equal(typeof Symbol.prototype.toString, 'function', 'Symbol#toString is a function');
+	// t.equal(String(foo), Symbol.prototype.toString.call(foo), 'Symbol#toString equals String of the same symbol');
+
+	t.equal(typeof Object.getOwnPropertySymbols, 'function', 'Object.getOwnPropertySymbols is a function');
+
+	/** @type {{ [k in symbol]?: unknown }} */
+	var obj = {};
+	var sym = Symbol('test');
+	var symObj = Object(sym);
+	t.notEqual(typeof sym, 'string', 'Symbol is not a string');
+	t.equal(Object.prototype.toString.call(sym), '[object Symbol]', 'symbol primitive Object#toStrings properly');
+	t.equal(Object.prototype.toString.call(symObj), '[object Symbol]', 'symbol primitive Object#toStrings properly');
+
+	var symVal = 42;
+	obj[sym] = symVal;
+	// eslint-disable-next-line no-restricted-syntax, no-unused-vars
+	for (var _ in obj) { t.fail('symbol property key was found in for..in of object'); }
+
+	t.deepEqual(Object.keys(obj), [], 'no enumerable own keys on symbol-valued object');
+	t.deepEqual(Object.getOwnPropertyNames(obj), [], 'no own names on symbol-valued object');
+	t.deepEqual(Object.getOwnPropertySymbols(obj), [sym], 'one own symbol on symbol-valued object');
+	t.equal(Object.prototype.propertyIsEnumerable.call(obj, sym), true, 'symbol is enumerable');
+	t.deepEqual(Object.getOwnPropertyDescriptor(obj, sym), {
+		configurable: true,
+		enumerable: true,
+		value: 42,
+		writable: true
+	}, 'property descriptor is correct');
+};
diff --git a/server/node_modules/has-symbols/tsconfig.json b/server/node_modules/has-symbols/tsconfig.json
new file mode 100644
index 0000000..ba99af4
--- /dev/null
+++ b/server/node_modules/has-symbols/tsconfig.json
@@ -0,0 +1,10 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "ES2021",
+		"maxNodeModuleJsDepth": 0,
+	},
+	"exclude": [
+		"coverage"
+	]
+}
diff --git a/server/node_modules/has-unicode/LICENSE b/server/node_modules/has-unicode/LICENSE
new file mode 100644
index 0000000..d42e25e
--- /dev/null
+++ b/server/node_modules/has-unicode/LICENSE
@@ -0,0 +1,14 @@
+Copyright (c) 2014, Rebecca Turner <me@re-becca.org>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
diff --git a/server/node_modules/has-unicode/README.md b/server/node_modules/has-unicode/README.md
new file mode 100644
index 0000000..5a03e59
--- /dev/null
+++ b/server/node_modules/has-unicode/README.md
@@ -0,0 +1,43 @@
+has-unicode
+===========
+
+Try to guess if your terminal supports unicode
+
+```javascript
+var hasUnicode = require("has-unicode")
+
+if (hasUnicode()) {
+  // the terminal probably has unicode support
+}
+```
+```javascript
+var hasUnicode = require("has-unicode").tryHarder
+hasUnicode(function(unicodeSupported) {
+  if (unicodeSupported) {
+    // the terminal probably has unicode support
+  }
+})
+```
+
+## Detecting Unicode
+
+What we actually detect is UTF-8 support, as that's what Node itself supports.
+If you have a UTF-16 locale then you won't be detected as unicode capable.
+
+### Windows
+
+Since at least Windows 7, `cmd` and `powershell` have been unicode capable,
+but unfortunately even then it's not guaranteed. In many localizations it
+still uses legacy code pages and there's no facility short of running
+programs or linking C++ that will let us detect this. As such, we
+report any Windows installation as NOT unicode capable, and recommend
+that you encourage your users to override this via config.
+
+### Unix Like Operating Systems
+
+We look at the environment variables `LC_ALL`, `LC_CTYPE`, and `LANG` in
+that order.  For `LC_ALL` and `LANG`, it looks for `.UTF-8` in the value. 
+For `LC_CTYPE` it looks to see if the value is `UTF-8`.  This is sufficient
+for most POSIX systems.  While locale data can be put in `/etc/locale.conf`
+as well, AFAIK it's always copied into the environment.
+
diff --git a/server/node_modules/has-unicode/index.js b/server/node_modules/has-unicode/index.js
new file mode 100644
index 0000000..9b0fe44
--- /dev/null
+++ b/server/node_modules/has-unicode/index.js
@@ -0,0 +1,16 @@
+"use strict"
+var os = require("os")
+
+var hasUnicode = module.exports = function () {
+  // Recent Win32 platforms (>XP) CAN support unicode in the console but
+  // don't have to, and in non-english locales often use traditional local
+  // code pages. There's no way, short of windows system calls or execing
+  // the chcp command line program to figure this out. As such, we default
+  // this to false and encourage your users to override it via config if
+  // appropriate.
+  if (os.type() == "Windows_NT") { return false }
+
+  var isUTF8 = /UTF-?8$/i
+  var ctype = process.env.LC_ALL || process.env.LC_CTYPE || process.env.LANG
+  return isUTF8.test(ctype)
+}
diff --git a/server/node_modules/has-unicode/package.json b/server/node_modules/has-unicode/package.json
new file mode 100644
index 0000000..ebe9d76
--- /dev/null
+++ b/server/node_modules/has-unicode/package.json
@@ -0,0 +1,30 @@
+{
+  "name": "has-unicode",
+  "version": "2.0.1",
+  "description": "Try to guess if your terminal supports unicode",
+  "main": "index.js",
+  "scripts": {
+    "test": "tap test/*.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/iarna/has-unicode"
+  },
+  "keywords": [
+    "unicode",
+    "terminal"
+  ],
+  "files": [
+    "index.js"
+  ],
+  "author": "Rebecca Turner <me@re-becca.org>",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/iarna/has-unicode/issues"
+  },
+  "homepage": "https://github.com/iarna/has-unicode",
+  "devDependencies": {
+    "require-inject": "^1.3.0",
+    "tap": "^2.3.1"
+  }
+}
diff --git a/server/node_modules/hasown/.eslintrc b/server/node_modules/hasown/.eslintrc
new file mode 100644
index 0000000..3b5d9e9
--- /dev/null
+++ b/server/node_modules/hasown/.eslintrc
@@ -0,0 +1,5 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+}
diff --git a/server/node_modules/hasown/.github/FUNDING.yml b/server/node_modules/hasown/.github/FUNDING.yml
new file mode 100644
index 0000000..d68c8b7
--- /dev/null
+++ b/server/node_modules/hasown/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/hasown
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with a single custom sponsorship URL
diff --git a/server/node_modules/hasown/.nycrc b/server/node_modules/hasown/.nycrc
new file mode 100644
index 0000000..1826526
--- /dev/null
+++ b/server/node_modules/hasown/.nycrc
@@ -0,0 +1,13 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"lines": 86,
+	"statements": 85.93,
+	"functions": 82.43,
+	"branches": 76.06,
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/hasown/CHANGELOG.md b/server/node_modules/hasown/CHANGELOG.md
new file mode 100644
index 0000000..2b0a980
--- /dev/null
+++ b/server/node_modules/hasown/CHANGELOG.md
@@ -0,0 +1,40 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v2.0.2](https://github.com/inspect-js/hasOwn/compare/v2.0.1...v2.0.2) - 2024-03-10
+
+### Commits
+
+- [types] use shared config [`68e9d4d`](https://github.com/inspect-js/hasOwn/commit/68e9d4dab6facb4f05f02c6baea94a3f2a4e44b2)
+- [actions] remove redundant finisher; use reusable workflow [`241a68e`](https://github.com/inspect-js/hasOwn/commit/241a68e13ea1fe52bec5ba7f74144befc31fae7b)
+- [Tests] increase coverage [`4125c0d`](https://github.com/inspect-js/hasOwn/commit/4125c0d6121db56ae30e38346dfb0c000b04f0a7)
+- [Tests] skip `npm ls` in old node due to TS [`01b9282`](https://github.com/inspect-js/hasOwn/commit/01b92822f9971dea031eafdd14767df41d61c202)
+- [types] improve predicate type [`d340f85`](https://github.com/inspect-js/hasOwn/commit/d340f85ce02e286ef61096cbbb6697081d40a12b)
+- [Dev Deps] update `tape` [`70089fc`](https://github.com/inspect-js/hasOwn/commit/70089fcf544e64acc024cbe60f5a9b00acad86de)
+- [Tests] use `@arethetypeswrong/cli` [`50b272c`](https://github.com/inspect-js/hasOwn/commit/50b272c829f40d053a3dd91c9796e0ac0b2af084)
+
+## [v2.0.1](https://github.com/inspect-js/hasOwn/compare/v2.0.0...v2.0.1) - 2024-02-10
+
+### Commits
+
+- [types] use a handwritten d.ts file; fix exported type [`012b989`](https://github.com/inspect-js/hasOwn/commit/012b9898ccf91dc441e2ebf594ff70270a5fda58)
+- [Dev Deps] update `@types/function-bind`, `@types/mock-property`, `@types/tape`, `aud`, `mock-property`, `npmignore`, `tape`, `typescript` [`977a56f`](https://github.com/inspect-js/hasOwn/commit/977a56f51a1f8b20566f3c471612137894644025)
+- [meta] add `sideEffects` flag [`3a60b7b`](https://github.com/inspect-js/hasOwn/commit/3a60b7bf42fccd8c605e5f145a6fcc83b13cb46f)
+
+## [v2.0.0](https://github.com/inspect-js/hasOwn/compare/v1.0.1...v2.0.0) - 2023-10-19
+
+### Commits
+
+- revamped implementation, tests, readme [`72bf8b3`](https://github.com/inspect-js/hasOwn/commit/72bf8b338e77a638f0a290c63ffaed18339c36b4)
+- [meta] revamp package.json [`079775f`](https://github.com/inspect-js/hasOwn/commit/079775fb1ec72c1c6334069593617a0be3847458)
+- Only apps should have lockfiles [`6640e23`](https://github.com/inspect-js/hasOwn/commit/6640e233d1bb8b65260880f90787637db157d215)
+
+## v1.0.1 - 2023-10-10
+
+### Commits
+
+- Initial commit [`8dbfde6`](https://github.com/inspect-js/hasOwn/commit/8dbfde6e8fb0ebb076fab38d138f2984eb340a62)
diff --git a/server/node_modules/hasown/LICENSE b/server/node_modules/hasown/LICENSE
new file mode 100644
index 0000000..0314929
--- /dev/null
+++ b/server/node_modules/hasown/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) Jordan Harband and contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/hasown/README.md b/server/node_modules/hasown/README.md
new file mode 100644
index 0000000..f759b8a
--- /dev/null
+++ b/server/node_modules/hasown/README.md
@@ -0,0 +1,40 @@
+# hasown <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+A robust, ES3 compatible, "has own property" predicate.
+
+## Example
+
+```js
+const assert = require('assert');
+const hasOwn = require('hasown');
+
+assert.equal(hasOwn({}, 'toString'), false);
+assert.equal(hasOwn([], 'length'), true);
+assert.equal(hasOwn({ a: 42 }, 'a'), true);
+```
+
+## Tests
+Simply clone the repo, `npm install`, and run `npm test`
+
+[package-url]: https://npmjs.org/package/hasown
+[npm-version-svg]: https://versionbadg.es/inspect-js/hasown.svg
+[deps-svg]: https://david-dm.org/inspect-js/hasOwn.svg
+[deps-url]: https://david-dm.org/inspect-js/hasOwn
+[dev-deps-svg]: https://david-dm.org/inspect-js/hasOwn/dev-status.svg
+[dev-deps-url]: https://david-dm.org/inspect-js/hasOwn#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/hasown.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/hasown.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/hasown.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=hasown
+[codecov-image]: https://codecov.io/gh/inspect-js/hasOwn/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/inspect-js/hasOwn/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/inspect-js/hasOwn
+[actions-url]: https://github.com/inspect-js/hasOwn/actions
diff --git a/server/node_modules/hasown/index.d.ts b/server/node_modules/hasown/index.d.ts
new file mode 100644
index 0000000..aafdf3b
--- /dev/null
+++ b/server/node_modules/hasown/index.d.ts
@@ -0,0 +1,3 @@
+declare function hasOwn<O, K extends PropertyKey, V = unknown>(o: O, p: K): o is O & Record<K, V>;
+
+export = hasOwn;
diff --git a/server/node_modules/hasown/index.js b/server/node_modules/hasown/index.js
new file mode 100644
index 0000000..34e6059
--- /dev/null
+++ b/server/node_modules/hasown/index.js
@@ -0,0 +1,8 @@
+'use strict';
+
+var call = Function.prototype.call;
+var $hasOwn = Object.prototype.hasOwnProperty;
+var bind = require('function-bind');
+
+/** @type {import('.')} */
+module.exports = bind.call(call, $hasOwn);
diff --git a/server/node_modules/hasown/package.json b/server/node_modules/hasown/package.json
new file mode 100644
index 0000000..8502e13
--- /dev/null
+++ b/server/node_modules/hasown/package.json
@@ -0,0 +1,92 @@
+{
+	"name": "hasown",
+	"version": "2.0.2",
+	"description": "A robust, ES3 compatible, \"has own property\" predicate.",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./package.json": "./package.json"
+	},
+	"types": "index.d.ts",
+	"sideEffects": false,
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prepublishOnly": "safe-publish-latest",
+		"prelint": "evalmd README.md",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "npm run tsc",
+		"pretest": "npm run lint",
+		"tsc": "tsc -p .",
+		"posttsc": "attw -P",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "aud --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/inspect-js/hasOwn.git"
+	},
+	"keywords": [
+		"has",
+		"hasOwnProperty",
+		"hasOwn",
+		"has-own",
+		"own",
+		"has",
+		"property",
+		"in",
+		"javascript",
+		"ecmascript"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/inspect-js/hasOwn/issues"
+	},
+	"homepage": "https://github.com/inspect-js/hasOwn#readme",
+	"dependencies": {
+		"function-bind": "^1.1.2"
+	},
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.15.1",
+		"@ljharb/eslint-config": "^21.1.0",
+		"@ljharb/tsconfig": "^0.2.0",
+		"@types/function-bind": "^1.1.10",
+		"@types/mock-property": "^1.0.2",
+		"@types/tape": "^5.6.4",
+		"aud": "^2.0.4",
+		"auto-changelog": "^2.4.0",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"in-publish": "^2.0.1",
+		"mock-property": "^1.0.3",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.7.5",
+		"typescript": "next"
+	},
+	"engines": {
+		"node": ">= 0.4"
+	},
+	"testling": {
+		"files": "test/index.js"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows",
+			"test"
+		]
+	}
+}
diff --git a/server/node_modules/hasown/tsconfig.json b/server/node_modules/hasown/tsconfig.json
new file mode 100644
index 0000000..0930c56
--- /dev/null
+++ b/server/node_modules/hasown/tsconfig.json
@@ -0,0 +1,6 @@
+{
+  "extends": "@ljharb/tsconfig",
+  "exclude": [
+    "coverage",
+  ],
+}
diff --git a/server/node_modules/http-cache-semantics/LICENSE b/server/node_modules/http-cache-semantics/LICENSE
new file mode 100644
index 0000000..493d2ea
--- /dev/null
+++ b/server/node_modules/http-cache-semantics/LICENSE
@@ -0,0 +1,9 @@
+Copyright 2016-2018 Kornel Lesiński
+
+Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/server/node_modules/http-cache-semantics/README.md b/server/node_modules/http-cache-semantics/README.md
new file mode 100644
index 0000000..de951c1
--- /dev/null
+++ b/server/node_modules/http-cache-semantics/README.md
@@ -0,0 +1,268 @@
+# Can I cache this?
+
+This library tells when responses can be reused from a cache, taking into account [HTTP RFC 7234/9111](http://httpwg.org/specs/rfc9111.html) rules for user agents and shared caches.
+It also implements `stale-if-error` and `stale-while-revalidate` from [RFC 5861](https://tools.ietf.org/html/rfc5861).
+It's aware of many tricky details such as the `Vary` header, proxy revalidation, and authenticated responses.
+
+## Basic Usage
+
+`CachePolicy` is a metadata object that is meant to be stored in the cache, and it will keep track of cacheability of the response.
+
+Cacheability of an HTTP response depends on how it was requested, so both `request` and `response` are required to create the policy.
+
+```js
+const policy = new CachePolicy(request, response, options);
+
+if (!policy.storable()) {
+    // throw the response away, it's not usable at all
+    return;
+}
+
+// Cache the data AND the policy object in your cache
+// (this is pseudocode, roll your own cache (lru-cache package works))
+letsPretendThisIsSomeCache.set(
+    request.url,
+    { policy, body: response.body }, // you only need to store the response body. CachePolicy holds the headers.
+    policy.timeToLive()
+);
+```
+
+```js
+// And later, when you receive a new request:
+const { policy, body } = letsPretendThisIsSomeCache.get(newRequest.url);
+
+// It's not enough that it exists in the cache, it has to match the new request, too:
+if (policy && policy.satisfiesWithoutRevalidation(newRequest)) {
+    // OK, the previous response can be used to respond to the `newRequest`.
+    // Response headers have to be updated, e.g. to add Age and remove uncacheable headers.
+    return {
+        headers: policy.responseHeaders(),
+        body,
+    }
+}
+
+// Cache miss. See revalidationHeaders() and revalidatedPolicy() for advanced usage.
+```
+
+It may be surprising, but it's not enough for an HTTP response to be [fresh](#yo-fresh) to satisfy a request. It may need to match request headers specified in `Vary`. Even a matching fresh response may still not be usable if the new request restricted cacheability, etc.
+
+The key method is `satisfiesWithoutRevalidation(newRequest)`, which checks whether the `newRequest` is compatible with the original request and whether all caching conditions are met.
+
+### Constructor options
+
+Request and response must have a `headers` property with all header names in lower case. `url`, `status` and `method` are optional (defaults are any URL, status `200`, and `GET` method).
+
+```js
+const request = {
+    url: '/',
+    method: 'GET',
+    headers: {
+        accept: '*/*',
+    },
+};
+
+const response = {
+    status: 200,
+    headers: {
+        'cache-control': 'public, max-age=7234',
+    },
+};
+
+const options = {
+    shared: true,
+    cacheHeuristic: 0.1,
+    immutableMinTimeToLive: 24 * 3600 * 1000, // 24h
+    ignoreCargoCult: false,
+};
+```
+
+If `options.shared` is `true` (default), then the response is evaluated from a perspective of a shared cache (i.e. `private` is not cacheable and `s-maxage` is respected). If `options.shared` is `false`, then the response is evaluated from a perspective of a single-user cache (i.e. `private` is cacheable and `s-maxage` is ignored). `shared: true` is recommended for HTTP clients.
+
+`options.cacheHeuristic` is a fraction of response's age that is used as a fallback cache duration. The default is 0.1 (10%), e.g. if a file hasn't been modified for 100 days, it'll be cached for 100\*0.1 = 10 days.
+
+`options.immutableMinTimeToLive` is a number of milliseconds to assume as the default time to cache responses with `Cache-Control: immutable`. Note that [per RFC](http://httpwg.org/http-extensions/immutable.html) these can become stale, so `max-age` still overrides the default.
+
+If `options.ignoreCargoCult` is true, common anti-cache directives will be completely ignored if the non-standard `pre-check` and `post-check` directives are present. These two useless directives are most commonly found in bad StackOverflow answers and PHP's "session limiter" defaults.
+
+### `storable()`
+
+Returns `true` if the response can be stored in a cache. If it's `false` then you MUST NOT store either the request or the response.
+
+### `satisfiesWithoutRevalidation(newRequest)`
+
+Use this method to check whether the cached response is still fresh in the context of the new request.
+
+If it returns `true`, then the given `request` matches the original response this cache policy has been created with, and the response can be reused without contacting the server. Note that the old response can't be returned without being updated, see `responseHeaders()`.
+
+If it returns `false`, then the response may not be matching at all (e.g. it's for a different URL or method), or may require to be refreshed first (see `revalidationHeaders()`).
+
+### `responseHeaders()`
+
+Returns updated, filtered set of response headers to return to clients receiving the cached response. This function is necessary, because proxies MUST always remove hop-by-hop headers (such as `TE` and `Connection`) and update response's `Age` to avoid doubling cache time.
+
+```js
+cachedResponse.headers = cachePolicy.responseHeaders();
+```
+
+### `timeToLive()`
+
+Suggests a time in _milliseconds_ for how long this cache entry may be useful. This is not freshness, so always check with `satisfiesWithoutRevalidation()`. This time may be longer than response's `max-age` to allow for `stale-if-error` and `stale-while-revalidate`.
+
+After that time (when `timeToLive() <= 0`) the response may still be usable in certain cases, e.g. if client can explicitly allows stale responses.
+
+### `toObject()`/`fromObject(json)`
+
+You'll want to store the `CachePolicy` object along with the cached response. `obj = policy.toObject()` gives a plain JSON-serializable object. `policy = CachePolicy.fromObject(obj)` creates an instance from it.
+
+## Complete Usage
+
+### `evaluateRequest(newRequest)`
+
+Returns an object telling what to do next — optional `revalidation`, and optional `response` from cache. Either one of these properties will be present. Both may be present at the same time.
+
+```js
+{
+    // If defined, you must send a request to the server.
+    revalidation: {
+        headers: {}, // HTTP headers to use when sending the revalidation response
+        // If true, you MUST wait for a response from the server before using the cache
+        // If false, this is stale-while-revalidate. The cache is stale, but you can use it while you update it asynchronously.
+        synchronous: bool,
+    },
+    // If defined, you can use this cached response.
+    response: {
+        headers: {}, // Updated cached HTTP headers you must use when responding to the client
+    },
+}
+```
+
+### Example
+
+```js
+let cached = cacheStorage.get(incomingRequest.url);
+
+// Cache miss - make a request to the origin and cache it
+if (!cached) {
+    const newResponse = await makeRequest(incomingRequest);
+    const policy = new CachePolicy(incomingRequest, newResponse);
+
+    cacheStorage.set(
+        incomingRequest.url,
+        { policy, body: newResponse.body },
+        policy.timeToLive()
+    );
+
+    return {
+        // use responseHeaders() to remove hop-by-hop headers that should not be passed through proxies
+        headers: policy.responseHeaders(),
+        body: newResponse.body,
+    }
+}
+
+// There's something cached, see if it's a hit
+let { revalidation, response } = cached.policy.evaluateRequest(incomingRequest);
+
+// Revalidation always goes first
+if (revalidation) {
+    // It's very important to update the request headers to make a correct revalidation request
+    incomingRequest.headers = revalidation.headers; // Same as cached.policy.revalidationHeaders()
+
+    // The cache may be updated immediately or in the background,
+    // so use a Promise to optionally defer the update
+    const updatedResponsePromise = makeRequest(incomingRequest).then(() => {
+        // Refresh the old response with the new information, if applicable
+        const { policy, modified } = cached.policy.revalidatedPolicy(incomingRequest, newResponse);
+
+        const body = modified ? newResponse.body : cached.body;
+
+        // Update the cache with the newer response
+        if (policy.storable()) {
+            cacheStorage.set(
+                incomingRequest.url,
+                { policy, body },
+                policy.timeToLive()
+            );
+        }
+
+        return {
+            headers: policy.responseHeaders(), // these are from the new revalidated policy
+            body,
+        }
+    });
+
+    if (revalidation.synchronous) {
+        // If synchronous, then you MUST get a reply from the server first
+        return await updatedResponsePromise;
+    }
+
+    // If not synchronous, it can fall thru to returning the cached response,
+    // while the request to the server is happening in the background.
+}
+
+return {
+    headers: response.headers, // Same as cached.policy.responseHeaders()
+    body: cached.body,
+}
+```
+
+### Refreshing stale cache (revalidation)
+
+When a cached response has expired, it can be made fresh again by making a request to the origin server. The server may respond with status 304 (Not Modified) without sending the response body again, saving bandwidth.
+
+The following methods help perform the update efficiently and correctly.
+
+#### `revalidationHeaders(newRequest)`
+
+Returns updated, filtered set of request headers to send to the origin server to check if the cached response can be reused. These headers allow the origin server to return status 304 indicating the response is still fresh. All headers unrelated to caching are passed through as-is.
+
+Use this method when updating cache from the origin server. Also available in `evaluateRequest(newRequest).revalidation.headers`.
+
+```js
+updateRequest.headers = cachePolicy.revalidationHeaders(updateRequest);
+```
+
+#### `revalidatedPolicy(revalidationRequest, revalidationResponse)`
+
+Use this method to update the cache after receiving a new response from the origin server. It returns an object with two keys:
+
+-   `policy` — A new `CachePolicy` with HTTP headers updated from `revalidationResponse`. You can always replace the old cached `CachePolicy` with the new one.
+-   `modified` — Boolean indicating whether the response body has changed, and you should use the new response body sent by the server.
+    -   If `true`, you should use the new response body, and you can replace the old cached response with the updated one.
+    -   If `false`, then you should reuse the old cached response body. Either a valid 304 Not Modified response has been received, or an error happened and `stale-if-error` allows falling back to the cache.
+
+# Yo, FRESH
+
+![satisfiesWithoutRevalidation](fresh.jpg)
+
+## Used by
+
+-   [ImageOptim API](https://imageoptim.com/api), [make-fetch-happen](https://github.com/zkat/make-fetch-happen), [cacheable-request](https://www.npmjs.com/package/cacheable-request) ([got](https://www.npmjs.com/package/got)), [npm/registry-fetch](https://github.com/npm/registry-fetch), [etc.](https://github.com/kornelski/http-cache-semantics/network/dependents)
+-   [Rust version of this library](https://lib.rs/crates/http-cache-semantics).
+
+## Implemented
+
+-   `Cache-Control` response header with all the quirks.
+-   `Expires` with check for bad clocks.
+-   `Pragma` response header.
+-   `Age` response header.
+-   `Vary` response header.
+-   Default cacheability of statuses and methods.
+-   Requests for stale data.
+-   Filtering of hop-by-hop headers.
+-   Basic revalidation request
+-   `stale-if-error`
+-   `stale-while-revalidate`
+
+## Unimplemented
+
+-   Merging of range requests, `If-Range` (but correctly supports them as non-cacheable)
+-   Revalidation of multiple representations
+
+### Trusting server `Date`
+
+Per the RFC, the cache should take into account the time between server-supplied `Date` and the time it received the response. The RFC-mandated behavior creates two problems:
+
+ * Servers with incorrectly set timezone may add several hours to cache age (or more, if the clock is completely wrong).
+ * Even reasonably correct clocks may be off by a couple of seconds, breaking `max-age=1` trick (which is useful for reverse proxies on high-traffic servers).
+
+Previous versions of this library had an option to ignore the server date if it was "too inaccurate". To support the `max-age=1` trick the library also has to ignore dates that pretty accurate. There's no point of having an option to trust dates that are only a bit inaccurate, so this library won't trust any server dates. `max-age` will be interpreted from the time the response has been received, not from when it has been sent. This will affect only [RFC 1149 networks](https://tools.ietf.org/html/rfc1149).
diff --git a/server/node_modules/http-cache-semantics/index.js b/server/node_modules/http-cache-semantics/index.js
new file mode 100644
index 0000000..f01e9a1
--- /dev/null
+++ b/server/node_modules/http-cache-semantics/index.js
@@ -0,0 +1,928 @@
+'use strict';
+
+/**
+ * @typedef {Object} HttpRequest
+ * @property {Record<string, string>} headers - Request headers
+ * @property {string} [method] - HTTP method
+ * @property {string} [url] - Request URL
+ */
+
+/**
+ * @typedef {Object} HttpResponse
+ * @property {Record<string, string>} headers - Response headers
+ * @property {number} [status] - HTTP status code
+ */
+
+/**
+ * Set of default cacheable status codes per RFC 7231 section 6.1.
+ * @type {Set<number>}
+ */
+const statusCodeCacheableByDefault = new Set([
+    200,
+    203,
+    204,
+    206,
+    300,
+    301,
+    308,
+    404,
+    405,
+    410,
+    414,
+    501,
+]);
+
+/**
+ * Set of HTTP status codes that the cache implementation understands.
+ * Note: This implementation does not understand partial responses (206).
+ * @type {Set<number>}
+ */
+const understoodStatuses = new Set([
+    200,
+    203,
+    204,
+    300,
+    301,
+    302,
+    303,
+    307,
+    308,
+    404,
+    405,
+    410,
+    414,
+    501,
+]);
+
+/**
+ * Set of HTTP error status codes.
+ * @type {Set<number>}
+ */
+const errorStatusCodes = new Set([
+    500,
+    502,
+    503,
+    504,
+]);
+
+/**
+ * Object representing hop-by-hop headers that should be removed.
+ * @type {Record<string, boolean>}
+ */
+const hopByHopHeaders = {
+    date: true, // included, because we add Age update Date
+    connection: true,
+    'keep-alive': true,
+    'proxy-authenticate': true,
+    'proxy-authorization': true,
+    te: true,
+    trailer: true,
+    'transfer-encoding': true,
+    upgrade: true,
+};
+
+/**
+ * Headers that are excluded from revalidation update.
+ * @type {Record<string, boolean>}
+ */
+const excludedFromRevalidationUpdate = {
+    // Since the old body is reused, it doesn't make sense to change properties of the body
+    'content-length': true,
+    'content-encoding': true,
+    'transfer-encoding': true,
+    'content-range': true,
+};
+
+/**
+ * Converts a string to a number or returns zero if the conversion fails.
+ * @param {string} s - The string to convert.
+ * @returns {number} The parsed number or 0.
+ */
+function toNumberOrZero(s) {
+    const n = parseInt(s, 10);
+    return isFinite(n) ? n : 0;
+}
+
+/**
+ * Determines if the given response is an error response.
+ * Implements RFC 5861 behavior.
+ * @param {HttpResponse|undefined} response - The HTTP response object.
+ * @returns {boolean} true if the response is an error or undefined, false otherwise.
+ */
+function isErrorResponse(response) {
+    // consider undefined response as faulty
+    if (!response) {
+        return true;
+    }
+    return errorStatusCodes.has(response.status);
+}
+
+/**
+ * Parses a Cache-Control header string into an object.
+ * @param {string} [header] - The Cache-Control header value.
+ * @returns {Record<string, string|boolean>} An object representing Cache-Control directives.
+ */
+function parseCacheControl(header) {
+    /** @type {Record<string, string|boolean>} */
+    const cc = {};
+    if (!header) return cc;
+
+    // TODO: When there is more than one value present for a given directive (e.g., two Expires header fields, multiple Cache-Control: max-age directives),
+    // the directive's value is considered invalid. Caches are encouraged to consider responses that have invalid freshness information to be stale
+    const parts = header.trim().split(/,/);
+    for (const part of parts) {
+        const [k, v] = part.split(/=/, 2);
+        cc[k.trim()] = v === undefined ? true : v.trim().replace(/^"|"$/g, '');
+    }
+
+    return cc;
+}
+
+/**
+ * Formats a Cache-Control directives object into a header string.
+ * @param {Record<string, string|boolean>} cc - The Cache-Control directives.
+ * @returns {string|undefined} A formatted Cache-Control header string or undefined if empty.
+ */
+function formatCacheControl(cc) {
+    let parts = [];
+    for (const k in cc) {
+        const v = cc[k];
+        parts.push(v === true ? k : k + '=' + v);
+    }
+    if (!parts.length) {
+        return undefined;
+    }
+    return parts.join(', ');
+}
+
+module.exports = class CachePolicy {
+    /**
+     * Creates a new CachePolicy instance.
+     * @param {HttpRequest} req - Incoming client request.
+     * @param {HttpResponse} res - Received server response.
+     * @param {Object} [options={}] - Configuration options.
+     * @param {boolean} [options.shared=true] - Is the cache shared (a public proxy)? `false` for personal browser caches.
+     * @param {number} [options.cacheHeuristic=0.1] - Fallback heuristic (age fraction) for cache duration.
+     * @param {number} [options.immutableMinTimeToLive=86400000] - Minimum TTL for immutable responses in milliseconds.
+     * @param {boolean} [options.ignoreCargoCult=false] - Detect nonsense cache headers, and override them.
+     * @param {any} [options._fromObject] - Internal parameter for deserialization. Do not use.
+     */
+    constructor(
+        req,
+        res,
+        {
+            shared,
+            cacheHeuristic,
+            immutableMinTimeToLive,
+            ignoreCargoCult,
+            _fromObject,
+        } = {}
+    ) {
+        if (_fromObject) {
+            this._fromObject(_fromObject);
+            return;
+        }
+
+        if (!res || !res.headers) {
+            throw Error('Response headers missing');
+        }
+        this._assertRequestHasHeaders(req);
+
+        /** @type {number} Timestamp when the response was received */
+        this._responseTime = this.now();
+        /** @type {boolean} Indicates if the cache is shared */
+        this._isShared = shared !== false;
+        /** @type {boolean} Indicates if legacy cargo cult directives should be ignored */
+        this._ignoreCargoCult = !!ignoreCargoCult;
+        /** @type {number} Heuristic cache fraction */
+        this._cacheHeuristic =
+            undefined !== cacheHeuristic ? cacheHeuristic : 0.1; // 10% matches IE
+        /** @type {number} Minimum TTL for immutable responses in ms */
+        this._immutableMinTtl =
+            undefined !== immutableMinTimeToLive
+                ? immutableMinTimeToLive
+                : 24 * 3600 * 1000;
+
+        /** @type {number} HTTP status code */
+        this._status = 'status' in res ? res.status : 200;
+        /** @type {Record<string, string>} Response headers */
+        this._resHeaders = res.headers;
+        /** @type {Record<string, string|boolean>} Parsed Cache-Control directives from response */
+        this._rescc = parseCacheControl(res.headers['cache-control']);
+        /** @type {string} HTTP method (e.g., GET, POST) */
+        this._method = 'method' in req ? req.method : 'GET';
+        /** @type {string} Request URL */
+        this._url = req.url;
+        /** @type {string} Host header from the request */
+        this._host = req.headers.host;
+        /** @type {boolean} Whether the request does not include an Authorization header */
+        this._noAuthorization = !req.headers.authorization;
+        /** @type {Record<string, string>|null} Request headers used for Vary matching */
+        this._reqHeaders = res.headers.vary ? req.headers : null; // Don't keep all request headers if they won't be used
+        /** @type {Record<string, string|boolean>} Parsed Cache-Control directives from request */
+        this._reqcc = parseCacheControl(req.headers['cache-control']);
+
+        // Assume that if someone uses legacy, non-standard uncecessary options they don't understand caching,
+        // so there's no point stricly adhering to the blindly copy&pasted directives.
+        if (
+            this._ignoreCargoCult &&
+            'pre-check' in this._rescc &&
+            'post-check' in this._rescc
+        ) {
+            delete this._rescc['pre-check'];
+            delete this._rescc['post-check'];
+            delete this._rescc['no-cache'];
+            delete this._rescc['no-store'];
+            delete this._rescc['must-revalidate'];
+            this._resHeaders = Object.assign({}, this._resHeaders, {
+                'cache-control': formatCacheControl(this._rescc),
+            });
+            delete this._resHeaders.expires;
+            delete this._resHeaders.pragma;
+        }
+
+        // When the Cache-Control header field is not present in a request, caches MUST consider the no-cache request pragma-directive
+        // as having the same effect as if "Cache-Control: no-cache" were present (see Section 5.2.1).
+        if (
+            res.headers['cache-control'] == null &&
+            /no-cache/.test(res.headers.pragma)
+        ) {
+            this._rescc['no-cache'] = true;
+        }
+    }
+
+    /**
+     * You can monkey-patch it for testing.
+     * @returns {number} Current time in milliseconds.
+     */
+    now() {
+        return Date.now();
+    }
+
+    /**
+     * Determines if the response is storable in a cache.
+     * @returns {boolean} `false` if can never be cached.
+     */
+    storable() {
+        // The "no-store" request directive indicates that a cache MUST NOT store any part of either this request or any response to it.
+        return !!(
+            !this._reqcc['no-store'] &&
+            // A cache MUST NOT store a response to any request, unless:
+            // The request method is understood by the cache and defined as being cacheable, and
+            ('GET' === this._method ||
+                'HEAD' === this._method ||
+                ('POST' === this._method && this._hasExplicitExpiration())) &&
+            // the response status code is understood by the cache, and
+            understoodStatuses.has(this._status) &&
+            // the "no-store" cache directive does not appear in request or response header fields, and
+            !this._rescc['no-store'] &&
+            // the "private" response directive does not appear in the response, if the cache is shared, and
+            (!this._isShared || !this._rescc.private) &&
+            // the Authorization header field does not appear in the request, if the cache is shared,
+            (!this._isShared ||
+                this._noAuthorization ||
+                this._allowsStoringAuthenticated()) &&
+            // the response either:
+            // contains an Expires header field, or
+            (this._resHeaders.expires ||
+                // contains a max-age response directive, or
+                // contains a s-maxage response directive and the cache is shared, or
+                // contains a public response directive.
+                this._rescc['max-age'] ||
+                (this._isShared && this._rescc['s-maxage']) ||
+                this._rescc.public ||
+                // has a status code that is defined as cacheable by default
+                statusCodeCacheableByDefault.has(this._status))
+        );
+    }
+
+    /**
+     * @returns {boolean} true if expiration is explicitly defined.
+     */
+    _hasExplicitExpiration() {
+        // 4.2.1 Calculating Freshness Lifetime
+        return !!(
+            (this._isShared && this._rescc['s-maxage']) ||
+            this._rescc['max-age'] ||
+            this._resHeaders.expires
+        );
+    }
+
+    /**
+     * @param {HttpRequest} req - a request
+     * @throws {Error} if the headers are missing.
+     */
+    _assertRequestHasHeaders(req) {
+        if (!req || !req.headers) {
+            throw Error('Request headers missing');
+        }
+    }
+
+    /**
+     * Checks if the request matches the cache and can be satisfied from the cache immediately,
+     * without having to make a request to the server.
+     *
+     * This doesn't support `stale-while-revalidate`. See `evaluateRequest()` for a more complete solution.
+     *
+     * @param {HttpRequest} req - The new incoming HTTP request.
+     * @returns {boolean} `true`` if the cached response used to construct this cache policy satisfies the request without revalidation.
+     */
+    satisfiesWithoutRevalidation(req) {
+        const result = this.evaluateRequest(req);
+        return !result.revalidation;
+    }
+
+    /**
+     * @param {{headers: Record<string, string>, synchronous: boolean}|undefined} revalidation - Revalidation information, if any.
+     * @returns {{response: {headers: Record<string, string>}, revalidation: {headers: Record<string, string>, synchronous: boolean}|undefined}} An object with a cached response headers and revalidation info.
+     */
+    _evaluateRequestHitResult(revalidation) {
+        return {
+            response: {
+                headers: this.responseHeaders(),
+            },
+            revalidation,
+        };
+    }
+
+    /**
+     * @param {HttpRequest} request - new incoming
+     * @param {boolean} synchronous - whether revalidation must be synchronous (not s-w-r).
+     * @returns {{headers: Record<string, string>, synchronous: boolean}} An object with revalidation headers and a synchronous flag.
+     */
+    _evaluateRequestRevalidation(request, synchronous) {
+        return {
+            synchronous,
+            headers: this.revalidationHeaders(request),
+        };
+    }
+
+    /**
+     * @param {HttpRequest} request - new incoming
+     * @returns {{response: undefined, revalidation: {headers: Record<string, string>, synchronous: boolean}}} An object indicating no cached response and revalidation details.
+     */
+    _evaluateRequestMissResult(request) {
+        return {
+            response: undefined,
+            revalidation: this._evaluateRequestRevalidation(request, true),
+        };
+    }
+
+    /**
+     * Checks if the given request matches this cache entry, and how the cache can be used to satisfy it. Returns an object with:
+     *
+     * ```
+     * {
+     *     // If defined, you must send a request to the server.
+     *     revalidation: {
+     *         headers: {}, // HTTP headers to use when sending the revalidation response
+     *         // If true, you MUST wait for a response from the server before using the cache
+     *         // If false, this is stale-while-revalidate. The cache is stale, but you can use it while you update it asynchronously.
+     *         synchronous: bool,
+     *     },
+     *     // If defined, you can use this cached response.
+     *     response: {
+     *         headers: {}, // Updated cached HTTP headers you must use when responding to the client
+     *     },
+     * }
+     * ```
+     * @param {HttpRequest} req - new incoming HTTP request
+     * @returns {{response: {headers: Record<string, string>}|undefined, revalidation: {headers: Record<string, string>, synchronous: boolean}|undefined}} An object containing keys:
+     *   - revalidation: { headers: Record<string, string>, synchronous: boolean } Set if you should send this to the origin server
+     *   - response: { headers: Record<string, string> } Set if you can respond to the client with these cached headers
+     */
+    evaluateRequest(req) {
+        this._assertRequestHasHeaders(req);
+
+        // In all circumstances, a cache MUST NOT ignore the must-revalidate directive
+        if (this._rescc['must-revalidate']) {
+            return this._evaluateRequestMissResult(req);
+        }
+
+        if (!this._requestMatches(req, false)) {
+            return this._evaluateRequestMissResult(req);
+        }
+
+        // When presented with a request, a cache MUST NOT reuse a stored response, unless:
+        // the presented request does not contain the no-cache pragma (Section 5.4), nor the no-cache cache directive,
+        // unless the stored response is successfully validated (Section 4.3), and
+        const requestCC = parseCacheControl(req.headers['cache-control']);
+
+        if (requestCC['no-cache'] || /no-cache/.test(req.headers.pragma)) {
+            return this._evaluateRequestMissResult(req);
+        }
+
+        if (requestCC['max-age'] && this.age() > toNumberOrZero(requestCC['max-age'])) {
+            return this._evaluateRequestMissResult(req);
+        }
+
+        if (requestCC['min-fresh'] && this.maxAge() - this.age() < toNumberOrZero(requestCC['min-fresh'])) {
+            return this._evaluateRequestMissResult(req);
+        }
+
+        // the stored response is either:
+        // fresh, or allowed to be served stale
+        if (this.stale()) {
+            // If a value is present, then the client is willing to accept a response that has
+            // exceeded its freshness lifetime by no more than the specified number of seconds
+            const allowsStaleWithoutRevalidation = 'max-stale' in requestCC &&
+                (true === requestCC['max-stale'] || requestCC['max-stale'] > this.age() - this.maxAge());
+
+            if (allowsStaleWithoutRevalidation) {
+                return this._evaluateRequestHitResult(undefined);
+            }
+
+            if (this.useStaleWhileRevalidate()) {
+                return this._evaluateRequestHitResult(this._evaluateRequestRevalidation(req, false));
+            }
+
+            return this._evaluateRequestMissResult(req);
+        }
+
+        return this._evaluateRequestHitResult(undefined);
+    }
+
+    /**
+     * @param {HttpRequest} req - check if this is for the same cache entry
+     * @param {boolean} allowHeadMethod - allow a HEAD method to match.
+     * @returns {boolean} `true` if the request matches.
+     */
+    _requestMatches(req, allowHeadMethod) {
+        // The presented effective request URI and that of the stored response match, and
+        return !!(
+            (!this._url || this._url === req.url) &&
+            this._host === req.headers.host &&
+            // the request method associated with the stored response allows it to be used for the presented request, and
+            (!req.method ||
+                this._method === req.method ||
+                (allowHeadMethod && 'HEAD' === req.method)) &&
+            // selecting header fields nominated by the stored response (if any) match those presented, and
+            this._varyMatches(req)
+        );
+    }
+
+    /**
+     * Determines whether storing authenticated responses is allowed.
+     * @returns {boolean} `true` if allowed.
+     */
+    _allowsStoringAuthenticated() {
+        // following Cache-Control response directives (Section 5.2.2) have such an effect: must-revalidate, public, and s-maxage.
+        return !!(
+            this._rescc['must-revalidate'] ||
+            this._rescc.public ||
+            this._rescc['s-maxage']
+        );
+    }
+
+    /**
+     * Checks whether the Vary header in the response matches the new request.
+     * @param {HttpRequest} req - incoming HTTP request
+     * @returns {boolean} `true` if the vary headers match.
+     */
+    _varyMatches(req) {
+        if (!this._resHeaders.vary) {
+            return true;
+        }
+
+        // A Vary header field-value of "*" always fails to match
+        if (this._resHeaders.vary === '*') {
+            return false;
+        }
+
+        const fields = this._resHeaders.vary
+            .trim()
+            .toLowerCase()
+            .split(/\s*,\s*/);
+        for (const name of fields) {
+            if (req.headers[name] !== this._reqHeaders[name]) return false;
+        }
+        return true;
+    }
+
+    /**
+     * Creates a copy of the given headers without any hop-by-hop headers.
+     * @param {Record<string, string>} inHeaders - old headers from the cached response
+     * @returns {Record<string, string>} A new headers object without hop-by-hop headers.
+     */
+    _copyWithoutHopByHopHeaders(inHeaders) {
+        /** @type {Record<string, string>} */
+        const headers = {};
+        for (const name in inHeaders) {
+            if (hopByHopHeaders[name]) continue;
+            headers[name] = inHeaders[name];
+        }
+        // 9.1.  Connection
+        if (inHeaders.connection) {
+            const tokens = inHeaders.connection.trim().split(/\s*,\s*/);
+            for (const name of tokens) {
+                delete headers[name];
+            }
+        }
+        if (headers.warning) {
+            const warnings = headers.warning.split(/,/).filter(warning => {
+                return !/^\s*1[0-9][0-9]/.test(warning);
+            });
+            if (!warnings.length) {
+                delete headers.warning;
+            } else {
+                headers.warning = warnings.join(',').trim();
+            }
+        }
+        return headers;
+    }
+
+    /**
+     * Returns the response headers adjusted for serving the cached response.
+     * Removes hop-by-hop headers and updates the Age and Date headers.
+     * @returns {Record<string, string>} The adjusted response headers.
+     */
+    responseHeaders() {
+        const headers = this._copyWithoutHopByHopHeaders(this._resHeaders);
+        const age = this.age();
+
+        // A cache SHOULD generate 113 warning if it heuristically chose a freshness
+        // lifetime greater than 24 hours and the response's age is greater than 24 hours.
+        if (
+            age > 3600 * 24 &&
+            !this._hasExplicitExpiration() &&
+            this.maxAge() > 3600 * 24
+        ) {
+            headers.warning =
+                (headers.warning ? `${headers.warning}, ` : '') +
+                '113 - "rfc7234 5.5.4"';
+        }
+        headers.age = `${Math.round(age)}`;
+        headers.date = new Date(this.now()).toUTCString();
+        return headers;
+    }
+
+    /**
+     * Returns the Date header value from the response or the current time if invalid.
+     * @returns {number} Timestamp (in milliseconds) representing the Date header or response time.
+     */
+    date() {
+        const serverDate = Date.parse(this._resHeaders.date);
+        if (isFinite(serverDate)) {
+            return serverDate;
+        }
+        return this._responseTime;
+    }
+
+    /**
+     * Value of the Age header, in seconds, updated for the current time.
+     * May be fractional.
+     * @returns {number} The age in seconds.
+     */
+    age() {
+        let age = this._ageValue();
+
+        const residentTime = (this.now() - this._responseTime) / 1000;
+        return age + residentTime;
+    }
+
+    /**
+     * @returns {number} The Age header value as a number.
+     */
+    _ageValue() {
+        return toNumberOrZero(this._resHeaders.age);
+    }
+
+    /**
+     * Possibly outdated value of applicable max-age (or heuristic equivalent) in seconds.
+     * This counts since response's `Date`.
+     *
+     * For an up-to-date value, see `timeToLive()`.
+     *
+     * Returns the maximum age (freshness lifetime) of the response in seconds.
+     * @returns {number} The max-age value in seconds.
+     */
+    maxAge() {
+        if (!this.storable() || this._rescc['no-cache']) {
+            return 0;
+        }
+
+        // Shared responses with cookies are cacheable according to the RFC, but IMHO it'd be unwise to do so by default
+        // so this implementation requires explicit opt-in via public header
+        if (
+            this._isShared &&
+            (this._resHeaders['set-cookie'] &&
+                !this._rescc.public &&
+                !this._rescc.immutable)
+        ) {
+            return 0;
+        }
+
+        if (this._resHeaders.vary === '*') {
+            return 0;
+        }
+
+        if (this._isShared) {
+            if (this._rescc['proxy-revalidate']) {
+                return 0;
+            }
+            // if a response includes the s-maxage directive, a shared cache recipient MUST ignore the Expires field.
+            if (this._rescc['s-maxage']) {
+                return toNumberOrZero(this._rescc['s-maxage']);
+            }
+        }
+
+        // If a response includes a Cache-Control field with the max-age directive, a recipient MUST ignore the Expires field.
+        if (this._rescc['max-age']) {
+            return toNumberOrZero(this._rescc['max-age']);
+        }
+
+        const defaultMinTtl = this._rescc.immutable ? this._immutableMinTtl : 0;
+
+        const serverDate = this.date();
+        if (this._resHeaders.expires) {
+            const expires = Date.parse(this._resHeaders.expires);
+            // A cache recipient MUST interpret invalid date formats, especially the value "0", as representing a time in the past (i.e., "already expired").
+            if (Number.isNaN(expires) || expires < serverDate) {
+                return 0;
+            }
+            return Math.max(defaultMinTtl, (expires - serverDate) / 1000);
+        }
+
+        if (this._resHeaders['last-modified']) {
+            const lastModified = Date.parse(this._resHeaders['last-modified']);
+            if (isFinite(lastModified) && serverDate > lastModified) {
+                return Math.max(
+                    defaultMinTtl,
+                    ((serverDate - lastModified) / 1000) * this._cacheHeuristic
+                );
+            }
+        }
+
+        return defaultMinTtl;
+    }
+
+    /**
+     * Remaining time this cache entry may be useful for, in *milliseconds*.
+     * You can use this as an expiration time for your cache storage.
+     *
+     * Prefer this method over `maxAge()`, because it includes other factors like `age` and `stale-while-revalidate`.
+     * @returns {number} Time-to-live in milliseconds.
+     */
+    timeToLive() {
+        const age = this.maxAge() - this.age();
+        const staleIfErrorAge = age + toNumberOrZero(this._rescc['stale-if-error']);
+        const staleWhileRevalidateAge = age + toNumberOrZero(this._rescc['stale-while-revalidate']);
+        return Math.round(Math.max(0, age, staleIfErrorAge, staleWhileRevalidateAge) * 1000);
+    }
+
+    /**
+     * If true, this cache entry is past its expiration date.
+     * Note that stale cache may be useful sometimes, see `evaluateRequest()`.
+     * @returns {boolean} `false` doesn't mean it's fresh nor usable
+     */
+    stale() {
+        return this.maxAge() <= this.age();
+    }
+
+    /**
+     * @returns {boolean} `true` if `stale-if-error` condition allows use of a stale response.
+     */
+    _useStaleIfError() {
+        return this.maxAge() + toNumberOrZero(this._rescc['stale-if-error']) > this.age();
+    }
+
+    /** See `evaluateRequest()` for a more complete solution
+     * @returns {boolean} `true` if `stale-while-revalidate` is currently allowed.
+     */
+    useStaleWhileRevalidate() {
+        const swr = toNumberOrZero(this._rescc['stale-while-revalidate']);
+        return swr > 0 && this.maxAge() + swr > this.age();
+    }
+
+    /**
+     * Creates a `CachePolicy` instance from a serialized object.
+     * @param {Object} obj - The serialized object.
+     * @returns {CachePolicy} A new CachePolicy instance.
+     */
+    static fromObject(obj) {
+        return new this(undefined, undefined, { _fromObject: obj });
+    }
+
+    /**
+     * @param {any} obj - The serialized object.
+     * @throws {Error} If already initialized or if the object is invalid.
+     */
+    _fromObject(obj) {
+        if (this._responseTime) throw Error('Reinitialized');
+        if (!obj || obj.v !== 1) throw Error('Invalid serialization');
+
+        this._responseTime = obj.t;
+        this._isShared = obj.sh;
+        this._cacheHeuristic = obj.ch;
+        this._immutableMinTtl =
+            obj.imm !== undefined ? obj.imm : 24 * 3600 * 1000;
+        this._ignoreCargoCult = !!obj.icc;
+        this._status = obj.st;
+        this._resHeaders = obj.resh;
+        this._rescc = obj.rescc;
+        this._method = obj.m;
+        this._url = obj.u;
+        this._host = obj.h;
+        this._noAuthorization = obj.a;
+        this._reqHeaders = obj.reqh;
+        this._reqcc = obj.reqcc;
+    }
+
+    /**
+     * Serializes the `CachePolicy` instance into a JSON-serializable object.
+     * @returns {Object} The serialized object.
+     */
+    toObject() {
+        return {
+            v: 1,
+            t: this._responseTime,
+            sh: this._isShared,
+            ch: this._cacheHeuristic,
+            imm: this._immutableMinTtl,
+            icc: this._ignoreCargoCult,
+            st: this._status,
+            resh: this._resHeaders,
+            rescc: this._rescc,
+            m: this._method,
+            u: this._url,
+            h: this._host,
+            a: this._noAuthorization,
+            reqh: this._reqHeaders,
+            reqcc: this._reqcc,
+        };
+    }
+
+    /**
+     * Headers for sending to the origin server to revalidate stale response.
+     * Allows server to return 304 to allow reuse of the previous response.
+     *
+     * Hop by hop headers are always stripped.
+     * Revalidation headers may be added or removed, depending on request.
+     * @param {HttpRequest} incomingReq - The incoming HTTP request.
+     * @returns {Record<string, string>} The headers for the revalidation request.
+     */
+    revalidationHeaders(incomingReq) {
+        this._assertRequestHasHeaders(incomingReq);
+        const headers = this._copyWithoutHopByHopHeaders(incomingReq.headers);
+
+        // This implementation does not understand range requests
+        delete headers['if-range'];
+
+        if (!this._requestMatches(incomingReq, true) || !this.storable()) {
+            // revalidation allowed via HEAD
+            // not for the same resource, or wasn't allowed to be cached anyway
+            delete headers['if-none-match'];
+            delete headers['if-modified-since'];
+            return headers;
+        }
+
+        /* MUST send that entity-tag in any cache validation request (using If-Match or If-None-Match) if an entity-tag has been provided by the origin server. */
+        if (this._resHeaders.etag) {
+            headers['if-none-match'] = headers['if-none-match']
+                ? `${headers['if-none-match']}, ${this._resHeaders.etag}`
+                : this._resHeaders.etag;
+        }
+
+        // Clients MAY issue simple (non-subrange) GET requests with either weak validators or strong validators. Clients MUST NOT use weak validators in other forms of request.
+        const forbidsWeakValidators =
+            headers['accept-ranges'] ||
+            headers['if-match'] ||
+            headers['if-unmodified-since'] ||
+            (this._method && this._method != 'GET');
+
+        /* SHOULD send the Last-Modified value in non-subrange cache validation requests (using If-Modified-Since) if only a Last-Modified value has been provided by the origin server.
+        Note: This implementation does not understand partial responses (206) */
+        if (forbidsWeakValidators) {
+            delete headers['if-modified-since'];
+
+            if (headers['if-none-match']) {
+                const etags = headers['if-none-match']
+                    .split(/,/)
+                    .filter(etag => {
+                        return !/^\s*W\//.test(etag);
+                    });
+                if (!etags.length) {
+                    delete headers['if-none-match'];
+                } else {
+                    headers['if-none-match'] = etags.join(',').trim();
+                }
+            }
+        } else if (
+            this._resHeaders['last-modified'] &&
+            !headers['if-modified-since']
+        ) {
+            headers['if-modified-since'] = this._resHeaders['last-modified'];
+        }
+
+        return headers;
+    }
+
+    /**
+     * Creates new CachePolicy with information combined from the previews response,
+     * and the new revalidation response.
+     *
+     * Returns {policy, modified} where modified is a boolean indicating
+     * whether the response body has been modified, and old cached body can't be used.
+     *
+     * @param {HttpRequest} request - The latest HTTP request asking for the cached entry.
+     * @param {HttpResponse} response - The latest revalidation HTTP response from the origin server.
+     * @returns {{policy: CachePolicy, modified: boolean, matches: boolean}} The updated policy and modification status.
+     * @throws {Error} If the response headers are missing.
+     */
+    revalidatedPolicy(request, response) {
+        this._assertRequestHasHeaders(request);
+
+        if (this._useStaleIfError() && isErrorResponse(response)) {
+          return {
+              policy: this,
+              modified: false,
+              matches: true,
+          };
+        }
+
+        if (!response || !response.headers) {
+            throw Error('Response headers missing');
+        }
+
+        // These aren't going to be supported exactly, since one CachePolicy object
+        // doesn't know about all the other cached objects.
+        let matches = false;
+        if (response.status !== undefined && response.status != 304) {
+            matches = false;
+        } else if (
+            response.headers.etag &&
+            !/^\s*W\//.test(response.headers.etag)
+        ) {
+            // "All of the stored responses with the same strong validator are selected.
+            // If none of the stored responses contain the same strong validator,
+            // then the cache MUST NOT use the new response to update any stored responses."
+            matches =
+                this._resHeaders.etag &&
+                this._resHeaders.etag.replace(/^\s*W\//, '') ===
+                    response.headers.etag;
+        } else if (this._resHeaders.etag && response.headers.etag) {
+            // "If the new response contains a weak validator and that validator corresponds
+            // to one of the cache's stored responses,
+            // then the most recent of those matching stored responses is selected for update."
+            matches =
+                this._resHeaders.etag.replace(/^\s*W\//, '') ===
+                response.headers.etag.replace(/^\s*W\//, '');
+        } else if (this._resHeaders['last-modified']) {
+            matches =
+                this._resHeaders['last-modified'] ===
+                response.headers['last-modified'];
+        } else {
+            // If the new response does not include any form of validator (such as in the case where
+            // a client generates an If-Modified-Since request from a source other than the Last-Modified
+            // response header field), and there is only one stored response, and that stored response also
+            // lacks a validator, then that stored response is selected for update.
+            if (
+                !this._resHeaders.etag &&
+                !this._resHeaders['last-modified'] &&
+                !response.headers.etag &&
+                !response.headers['last-modified']
+            ) {
+                matches = true;
+            }
+        }
+
+        const optionsCopy = {
+            shared: this._isShared,
+            cacheHeuristic: this._cacheHeuristic,
+            immutableMinTimeToLive: this._immutableMinTtl,
+            ignoreCargoCult: this._ignoreCargoCult,
+        };
+
+        if (!matches) {
+            return {
+                policy: new this.constructor(request, response, optionsCopy),
+                // Client receiving 304 without body, even if it's invalid/mismatched has no option
+                // but to reuse a cached body. We don't have a good way to tell clients to do
+                // error recovery in such case.
+                modified: response.status != 304,
+                matches: false,
+            };
+        }
+
+        // use other header fields provided in the 304 (Not Modified) response to replace all instances
+        // of the corresponding header fields in the stored response.
+        const headers = {};
+        for (const k in this._resHeaders) {
+            headers[k] =
+                k in response.headers && !excludedFromRevalidationUpdate[k]
+                    ? response.headers[k]
+                    : this._resHeaders[k];
+        }
+
+        const newResponse = Object.assign({}, response, {
+            status: this._status,
+            method: this._method,
+            headers,
+        });
+        return {
+            policy: new this.constructor(request, newResponse, optionsCopy),
+            modified: false,
+            matches: true,
+        };
+    }
+};
diff --git a/server/node_modules/http-cache-semantics/package.json b/server/node_modules/http-cache-semantics/package.json
new file mode 100644
index 0000000..d45dfa1
--- /dev/null
+++ b/server/node_modules/http-cache-semantics/package.json
@@ -0,0 +1,22 @@
+{
+    "name": "http-cache-semantics",
+    "version": "4.2.0",
+    "description": "Parses Cache-Control and other headers. Helps building correct HTTP caches and proxies",
+    "repository": {
+        "type": "git",
+        "url": "git+https://github.com/kornelski/http-cache-semantics.git"
+    },
+    "main": "index.js",
+    "types": "index.js",
+    "scripts": {
+        "test": "mocha"
+    },
+    "files": [
+        "index.js"
+    ],
+    "author": "Kornel Lesiński <npms2@geekhood.net> (https://kornel.ski/)",
+    "license": "BSD-2-Clause",
+    "devDependencies": {
+        "mocha": "^11.0"
+    }
+}
diff --git a/server/node_modules/http-errors/HISTORY.md b/server/node_modules/http-errors/HISTORY.md
new file mode 100644
index 0000000..3d81d26
--- /dev/null
+++ b/server/node_modules/http-errors/HISTORY.md
@@ -0,0 +1,186 @@
+2.0.1 / 2025-11-20
+==================
+
+  * deps: use tilde notation for dependencies
+  * deps: update statuses to 2.0.2
+
+2.0.0 / 2021-12-17
+==================
+
+  * Drop support for Node.js 0.6
+  * Remove `I'mateapot` export; use `ImATeapot` instead
+  * Remove support for status being non-first argument
+  * Rename `UnorderedCollection` constructor to `TooEarly`
+  * deps: depd@2.0.0
+    - Replace internal `eval` usage with `Function` constructor
+    - Use instance methods on `process` to check for listeners
+  * deps: statuses@2.0.1
+    - Fix messaging casing of `418 I'm a Teapot`
+    - Remove code 306
+    - Rename `425 Unordered Collection` to standard `425 Too Early`
+
+2021-11-14 / 1.8.1
+==================
+
+  * deps: toidentifier@1.0.1
+
+2020-06-29 / 1.8.0
+==================
+
+  * Add `isHttpError` export to determine if value is an HTTP error
+  * deps: setprototypeof@1.2.0
+
+2019-06-24 / 1.7.3
+==================
+
+  * deps: inherits@2.0.4
+
+2019-02-18 / 1.7.2
+==================
+
+  * deps: setprototypeof@1.1.1
+
+2018-09-08 / 1.7.1
+==================
+
+  * Fix error creating objects in some environments
+
+2018-07-30 / 1.7.0
+==================
+
+  * Set constructor name when possible
+  * Use `toidentifier` module to make class names
+  * deps: statuses@'>= 1.5.0 < 2'
+
+2018-03-29 / 1.6.3
+==================
+
+  * deps: depd@~1.1.2
+    - perf: remove argument reassignment
+  * deps: setprototypeof@1.1.0
+  * deps: statuses@'>= 1.4.0 < 2'
+
+2017-08-04 / 1.6.2
+==================
+
+  * deps: depd@1.1.1
+    - Remove unnecessary `Buffer` loading
+
+2017-02-20 / 1.6.1
+==================
+
+  * deps: setprototypeof@1.0.3
+    - Fix shim for old browsers
+
+2017-02-14 / 1.6.0
+==================
+
+  * Accept custom 4xx and 5xx status codes in factory
+  * Add deprecation message to `"I'mateapot"` export
+  * Deprecate passing status code as anything except first argument in factory
+  * Deprecate using non-error status codes
+  * Make `message` property enumerable for `HttpError`s
+
+2016-11-16 / 1.5.1
+==================
+
+  * deps: inherits@2.0.3
+    - Fix issue loading in browser
+  * deps: setprototypeof@1.0.2
+  * deps: statuses@'>= 1.3.1 < 2'
+
+2016-05-18 / 1.5.0
+==================
+
+  * Support new code `421 Misdirected Request`
+  * Use `setprototypeof` module to replace `__proto__` setting
+  * deps: statuses@'>= 1.3.0 < 2'
+    - Add `421 Misdirected Request`
+    - perf: enable strict mode
+  * perf: enable strict mode
+
+2016-01-28 / 1.4.0
+==================
+
+  * Add `HttpError` export, for `err instanceof createError.HttpError`
+  * deps: inherits@2.0.1
+  * deps: statuses@'>= 1.2.1 < 2'
+    - Fix message for status 451
+    - Remove incorrect nginx status code
+
+2015-02-02 / 1.3.1
+==================
+
+  * Fix regression where status can be overwritten in `createError` `props`
+
+2015-02-01 / 1.3.0
+==================
+
+  * Construct errors using defined constructors from `createError`
+  * Fix error names that are not identifiers
+    - `createError["I'mateapot"]` is now `createError.ImATeapot`
+  * Set a meaningful `name` property on constructed errors
+
+2014-12-09 / 1.2.8
+==================
+
+  * Fix stack trace from exported function
+  * Remove `arguments.callee` usage
+
+2014-10-14 / 1.2.7
+==================
+
+  * Remove duplicate line
+
+2014-10-02 / 1.2.6
+==================
+
+  * Fix `expose` to be `true` for `ClientError` constructor
+
+2014-09-28 / 1.2.5
+==================
+
+  * deps: statuses@1
+
+2014-09-21 / 1.2.4
+==================
+
+  * Fix dependency version to work with old `npm`s
+
+2014-09-21 / 1.2.3
+==================
+
+  * deps: statuses@~1.1.0
+
+2014-09-21 / 1.2.2
+==================
+
+  * Fix publish error
+
+2014-09-21 / 1.2.1
+==================
+
+  * Support Node.js 0.6
+  * Use `inherits` instead of `util`
+
+2014-09-09 / 1.2.0
+==================
+
+  * Fix the way inheriting functions
+  * Support `expose` being provided in properties argument
+
+2014-09-08 / 1.1.0
+==================
+
+  * Default status to 500
+  * Support provided `error` to extend
+
+2014-09-08 / 1.0.1
+==================
+
+  * Fix accepting string message
+
+2014-09-08 / 1.0.0
+==================
+
+  * Initial release
diff --git a/server/node_modules/http-errors/LICENSE b/server/node_modules/http-errors/LICENSE
new file mode 100644
index 0000000..82af4df
--- /dev/null
+++ b/server/node_modules/http-errors/LICENSE
@@ -0,0 +1,23 @@
+
+The MIT License (MIT)
+
+Copyright (c) 2014 Jonathan Ong me@jongleberry.com
+Copyright (c) 2016 Douglas Christopher Wilson doug@somethingdoug.com
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/http-errors/README.md b/server/node_modules/http-errors/README.md
new file mode 100644
index 0000000..a8b7330
--- /dev/null
+++ b/server/node_modules/http-errors/README.md
@@ -0,0 +1,169 @@
+# http-errors
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][node-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][ci-image]][ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Create HTTP errors for Express, Koa, Connect, etc. with ease.
+
+## Install
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```console
+$ npm install http-errors
+```
+
+## Example
+
+```js
+var createError = require('http-errors')
+var express = require('express')
+var app = express()
+
+app.use(function (req, res, next) {
+  if (!req.user) return next(createError(401, 'Please login to view this page.'))
+  next()
+})
+```
+
+## API
+
+This is the current API, currently extracted from Koa and subject to change.
+
+### Error Properties
+
+- `expose` - can be used to signal if `message` should be sent to the client,
+  defaulting to `false` when `status` >= 500
+- `headers` - can be an object of header names to values to be sent to the
+  client, defaulting to `undefined`. When defined, the key names should all
+  be lower-cased
+- `message` - the traditional error message, which should be kept short and all
+  single line
+- `status` - the status code of the error, mirroring `statusCode` for general
+  compatibility
+- `statusCode` - the status code of the error, defaulting to `500`
+
+### createError([status], [message], [properties])
+
+Create a new error object with the given message `msg`.
+The error object inherits from `createError.HttpError`.
+
+```js
+var err = createError(404, 'This video does not exist!')
+```
+
+- `status: 500` - the status code as a number
+- `message` - the message of the error, defaulting to node's text for that status code.
+- `properties` - custom properties to attach to the object
+
+### createError([status], [error], [properties])
+
+Extend the given `error` object with `createError.HttpError`
+properties. This will not alter the inheritance of the given
+`error` object, and the modified `error` object is the
+return value.
+
+
+
+```js
+fs.readFile('foo.txt', function (err, buf) {
+  if (err) {
+    if (err.code === 'ENOENT') {
+      var httpError = createError(404, err, { expose: false })
+    } else {
+      var httpError = createError(500, err)
+    }
+  }
+})
+```
+
+- `status` - the status code as a number
+- `error` - the error object to extend
+- `properties` - custom properties to attach to the object
+
+### createError.isHttpError(val)
+
+Determine if the provided `val` is an `HttpError`. This will return `true`
+if the error inherits from the `HttpError` constructor of this module or
+matches the "duck type" for an error this module creates. All outputs from
+the `createError` factory will return `true` for this function, including
+if an non-`HttpError` was passed into the factory.
+
+### new createError\[code || name\](\[msg]\))
+
+Create a new error object with the given message `msg`.
+The error object inherits from `createError.HttpError`.
+
+```js
+var err = new createError.NotFound()
+```
+
+- `code` - the status code as a number
+- `name` - the name of the error as a "bumpy case", i.e. `NotFound` or `InternalServerError`.
+
+#### List of all constructors
+
+|Status Code|Constructor Name             |
+|-----------|-----------------------------|
+|400        |BadRequest                   |
+|401        |Unauthorized                 |
+|402        |PaymentRequired              |
+|403        |Forbidden                    |
+|404        |NotFound                     |
+|405        |MethodNotAllowed             |
+|406        |NotAcceptable                |
+|407        |ProxyAuthenticationRequired  |
+|408        |RequestTimeout               |
+|409        |Conflict                     |
+|410        |Gone                         |
+|411        |LengthRequired               |
+|412        |PreconditionFailed           |
+|413        |PayloadTooLarge              |
+|414        |URITooLong                   |
+|415        |UnsupportedMediaType         |
+|416        |RangeNotSatisfiable          |
+|417        |ExpectationFailed            |
+|418        |ImATeapot                    |
+|421        |MisdirectedRequest           |
+|422        |UnprocessableEntity          |
+|423        |Locked                       |
+|424        |FailedDependency             |
+|425        |TooEarly                     |
+|426        |UpgradeRequired              |
+|428        |PreconditionRequired         |
+|429        |TooManyRequests              |
+|431        |RequestHeaderFieldsTooLarge  |
+|451        |UnavailableForLegalReasons   |
+|500        |InternalServerError          |
+|501        |NotImplemented               |
+|502        |BadGateway                   |
+|503        |ServiceUnavailable           |
+|504        |GatewayTimeout               |
+|505        |HTTPVersionNotSupported      |
+|506        |VariantAlsoNegotiates        |
+|507        |InsufficientStorage          |
+|508        |LoopDetected                 |
+|509        |BandwidthLimitExceeded       |
+|510        |NotExtended                  |
+|511        |NetworkAuthenticationRequired|
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/jshttp/http-errors/master?label=ci
+[ci-url]: https://github.com/jshttp/http-errors/actions?query=workflow%3Aci
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/http-errors/master
+[coveralls-url]: https://coveralls.io/r/jshttp/http-errors?branch=master
+[node-image]: https://badgen.net/npm/node/http-errors
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/http-errors
+[npm-url]: https://npmjs.org/package/http-errors
+[npm-version-image]: https://badgen.net/npm/v/http-errors
+[travis-image]: https://badgen.net/travis/jshttp/http-errors/master
+[travis-url]: https://travis-ci.org/jshttp/http-errors
diff --git a/server/node_modules/http-errors/index.js b/server/node_modules/http-errors/index.js
new file mode 100644
index 0000000..82271f6
--- /dev/null
+++ b/server/node_modules/http-errors/index.js
@@ -0,0 +1,290 @@
+/*!
+ * http-errors
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var deprecate = require('depd')('http-errors')
+var setPrototypeOf = require('setprototypeof')
+var statuses = require('statuses')
+var inherits = require('inherits')
+var toIdentifier = require('toidentifier')
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = createError
+module.exports.HttpError = createHttpErrorConstructor()
+module.exports.isHttpError = createIsHttpErrorFunction(module.exports.HttpError)
+
+// Populate exports for all constructors
+populateConstructorExports(module.exports, statuses.codes, module.exports.HttpError)
+
+/**
+ * Get the code class of a status code.
+ * @private
+ */
+
+function codeClass (status) {
+  return Number(String(status).charAt(0) + '00')
+}
+
+/**
+ * Create a new HTTP Error.
+ *
+ * @returns {Error}
+ * @public
+ */
+
+function createError () {
+  // so much arity going on ~_~
+  var err
+  var msg
+  var status = 500
+  var props = {}
+  for (var i = 0; i < arguments.length; i++) {
+    var arg = arguments[i]
+    var type = typeof arg
+    if (type === 'object' && arg instanceof Error) {
+      err = arg
+      status = err.status || err.statusCode || status
+    } else if (type === 'number' && i === 0) {
+      status = arg
+    } else if (type === 'string') {
+      msg = arg
+    } else if (type === 'object') {
+      props = arg
+    } else {
+      throw new TypeError('argument #' + (i + 1) + ' unsupported type ' + type)
+    }
+  }
+
+  if (typeof status === 'number' && (status < 400 || status >= 600)) {
+    deprecate('non-error status code; use only 4xx or 5xx status codes')
+  }
+
+  if (typeof status !== 'number' ||
+    (!statuses.message[status] && (status < 400 || status >= 600))) {
+    status = 500
+  }
+
+  // constructor
+  var HttpError = createError[status] || createError[codeClass(status)]
+
+  if (!err) {
+    // create error
+    err = HttpError
+      ? new HttpError(msg)
+      : new Error(msg || statuses.message[status])
+    Error.captureStackTrace(err, createError)
+  }
+
+  if (!HttpError || !(err instanceof HttpError) || err.status !== status) {
+    // add properties to generic error
+    err.expose = status < 500
+    err.status = err.statusCode = status
+  }
+
+  for (var key in props) {
+    if (key !== 'status' && key !== 'statusCode') {
+      err[key] = props[key]
+    }
+  }
+
+  return err
+}
+
+/**
+ * Create HTTP error abstract base class.
+ * @private
+ */
+
+function createHttpErrorConstructor () {
+  function HttpError () {
+    throw new TypeError('cannot construct abstract class')
+  }
+
+  inherits(HttpError, Error)
+
+  return HttpError
+}
+
+/**
+ * Create a constructor for a client error.
+ * @private
+ */
+
+function createClientErrorConstructor (HttpError, name, code) {
+  var className = toClassName(name)
+
+  function ClientError (message) {
+    // create the error object
+    var msg = message != null ? message : statuses.message[code]
+    var err = new Error(msg)
+
+    // capture a stack trace to the construction point
+    Error.captureStackTrace(err, ClientError)
+
+    // adjust the [[Prototype]]
+    setPrototypeOf(err, ClientError.prototype)
+
+    // redefine the error message
+    Object.defineProperty(err, 'message', {
+      enumerable: true,
+      configurable: true,
+      value: msg,
+      writable: true
+    })
+
+    // redefine the error name
+    Object.defineProperty(err, 'name', {
+      enumerable: false,
+      configurable: true,
+      value: className,
+      writable: true
+    })
+
+    return err
+  }
+
+  inherits(ClientError, HttpError)
+  nameFunc(ClientError, className)
+
+  ClientError.prototype.status = code
+  ClientError.prototype.statusCode = code
+  ClientError.prototype.expose = true
+
+  return ClientError
+}
+
+/**
+ * Create function to test is a value is a HttpError.
+ * @private
+ */
+
+function createIsHttpErrorFunction (HttpError) {
+  return function isHttpError (val) {
+    if (!val || typeof val !== 'object') {
+      return false
+    }
+
+    if (val instanceof HttpError) {
+      return true
+    }
+
+    return val instanceof Error &&
+      typeof val.expose === 'boolean' &&
+      typeof val.statusCode === 'number' && val.status === val.statusCode
+  }
+}
+
+/**
+ * Create a constructor for a server error.
+ * @private
+ */
+
+function createServerErrorConstructor (HttpError, name, code) {
+  var className = toClassName(name)
+
+  function ServerError (message) {
+    // create the error object
+    var msg = message != null ? message : statuses.message[code]
+    var err = new Error(msg)
+
+    // capture a stack trace to the construction point
+    Error.captureStackTrace(err, ServerError)
+
+    // adjust the [[Prototype]]
+    setPrototypeOf(err, ServerError.prototype)
+
+    // redefine the error message
+    Object.defineProperty(err, 'message', {
+      enumerable: true,
+      configurable: true,
+      value: msg,
+      writable: true
+    })
+
+    // redefine the error name
+    Object.defineProperty(err, 'name', {
+      enumerable: false,
+      configurable: true,
+      value: className,
+      writable: true
+    })
+
+    return err
+  }
+
+  inherits(ServerError, HttpError)
+  nameFunc(ServerError, className)
+
+  ServerError.prototype.status = code
+  ServerError.prototype.statusCode = code
+  ServerError.prototype.expose = false
+
+  return ServerError
+}
+
+/**
+ * Set the name of a function, if possible.
+ * @private
+ */
+
+function nameFunc (func, name) {
+  var desc = Object.getOwnPropertyDescriptor(func, 'name')
+
+  if (desc && desc.configurable) {
+    desc.value = name
+    Object.defineProperty(func, 'name', desc)
+  }
+}
+
+/**
+ * Populate the exports object with constructors for every error class.
+ * @private
+ */
+
+function populateConstructorExports (exports, codes, HttpError) {
+  codes.forEach(function forEachCode (code) {
+    var CodeError
+    var name = toIdentifier(statuses.message[code])
+
+    switch (codeClass(code)) {
+      case 400:
+        CodeError = createClientErrorConstructor(HttpError, name, code)
+        break
+      case 500:
+        CodeError = createServerErrorConstructor(HttpError, name, code)
+        break
+    }
+
+    if (CodeError) {
+      // export the constructor
+      exports[code] = CodeError
+      exports[name] = CodeError
+    }
+  })
+}
+
+/**
+ * Get a class name from a name identifier.
+ *
+ * @param {string} name
+ * @returns {string}
+ * @private
+ */
+
+function toClassName (name) {
+  return name.slice(-5) === 'Error' ? name : name + 'Error'
+}
diff --git a/server/node_modules/http-errors/package.json b/server/node_modules/http-errors/package.json
new file mode 100644
index 0000000..4b46d62
--- /dev/null
+++ b/server/node_modules/http-errors/package.json
@@ -0,0 +1,54 @@
+{
+  "name": "http-errors",
+  "description": "Create HTTP error objects",
+  "version": "2.0.1",
+  "author": "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)",
+  "contributors": [
+    "Alan Plum <me@pluma.io>",
+    "Douglas Christopher Wilson <doug@somethingdoug.com>"
+  ],
+  "license": "MIT",
+  "repository": "jshttp/http-errors",
+  "funding": {
+    "type": "opencollective",
+    "url": "https://opencollective.com/express"
+  },
+  "dependencies": {
+    "depd": "~2.0.0",
+    "inherits": "~2.0.4",
+    "setprototypeof": "~1.2.0",
+    "statuses": "~2.0.2",
+    "toidentifier": "~1.0.1"
+  },
+  "devDependencies": {
+    "eslint": "7.32.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.32.0",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "5.2.0",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "9.1.3",
+    "nyc": "15.1.0"
+  },
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "lint": "eslint . && node ./scripts/lint-readme-list.js",
+    "test": "mocha --reporter spec",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  },
+  "keywords": [
+    "http",
+    "error"
+  ],
+  "files": [
+    "index.js",
+    "HISTORY.md",
+    "LICENSE",
+    "README.md"
+  ]
+}
diff --git a/server/node_modules/http-proxy-agent/README.md b/server/node_modules/http-proxy-agent/README.md
new file mode 100644
index 0000000..d60e206
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/README.md
@@ -0,0 +1,74 @@
+http-proxy-agent
+================
+### An HTTP(s) proxy `http.Agent` implementation for HTTP
+[![Build Status](https://github.com/TooTallNate/node-http-proxy-agent/workflows/Node%20CI/badge.svg)](https://github.com/TooTallNate/node-http-proxy-agent/actions?workflow=Node+CI)
+
+This module provides an `http.Agent` implementation that connects to a specified
+HTTP or HTTPS proxy server, and can be used with the built-in `http` module.
+
+__Note:__ For HTTP proxy usage with the `https` module, check out
+[`node-https-proxy-agent`](https://github.com/TooTallNate/node-https-proxy-agent).
+
+Installation
+------------
+
+Install with `npm`:
+
+``` bash
+$ npm install http-proxy-agent
+```
+
+
+Example
+-------
+
+``` js
+var url = require('url');
+var http = require('http');
+var HttpProxyAgent = require('http-proxy-agent');
+
+// HTTP/HTTPS proxy to connect to
+var proxy = process.env.http_proxy || 'http://168.63.76.32:3128';
+console.log('using proxy server %j', proxy);
+
+// HTTP endpoint for the proxy to connect to
+var endpoint = process.argv[2] || 'http://nodejs.org/api/';
+console.log('attempting to GET %j', endpoint);
+var opts = url.parse(endpoint);
+
+// create an instance of the `HttpProxyAgent` class with the proxy server information
+var agent = new HttpProxyAgent(proxy);
+opts.agent = agent;
+
+http.get(opts, function (res) {
+  console.log('"response" event!', res.headers);
+  res.pipe(process.stdout);
+});
+```
+
+
+License
+-------
+
+(The MIT License)
+
+Copyright (c) 2013 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/http-proxy-agent/dist/agent.d.ts b/server/node_modules/http-proxy-agent/dist/agent.d.ts
new file mode 100644
index 0000000..3f043f7
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/dist/agent.d.ts
@@ -0,0 +1,32 @@
+/// <reference types="node" />
+import net from 'net';
+import { Agent, ClientRequest, RequestOptions } from 'agent-base';
+import { HttpProxyAgentOptions } from '.';
+interface HttpProxyAgentClientRequest extends ClientRequest {
+    path: string;
+    output?: string[];
+    outputData?: {
+        data: string;
+    }[];
+    _header?: string | null;
+    _implicitHeader(): void;
+}
+/**
+ * The `HttpProxyAgent` implements an HTTP Agent subclass that connects
+ * to the specified "HTTP proxy server" in order to proxy HTTP requests.
+ *
+ * @api public
+ */
+export default class HttpProxyAgent extends Agent {
+    private secureProxy;
+    private proxy;
+    constructor(_opts: string | HttpProxyAgentOptions);
+    /**
+     * Called when the node-core HTTP client library is creating a
+     * new HTTP request.
+     *
+     * @api protected
+     */
+    callback(req: HttpProxyAgentClientRequest, opts: RequestOptions): Promise<net.Socket>;
+}
+export {};
diff --git a/server/node_modules/http-proxy-agent/dist/agent.js b/server/node_modules/http-proxy-agent/dist/agent.js
new file mode 100644
index 0000000..0252850
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/dist/agent.js
@@ -0,0 +1,145 @@
+"use strict";
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+const net_1 = __importDefault(require("net"));
+const tls_1 = __importDefault(require("tls"));
+const url_1 = __importDefault(require("url"));
+const debug_1 = __importDefault(require("debug"));
+const once_1 = __importDefault(require("@tootallnate/once"));
+const agent_base_1 = require("agent-base");
+const debug = debug_1.default('http-proxy-agent');
+function isHTTPS(protocol) {
+    return typeof protocol === 'string' ? /^https:?$/i.test(protocol) : false;
+}
+/**
+ * The `HttpProxyAgent` implements an HTTP Agent subclass that connects
+ * to the specified "HTTP proxy server" in order to proxy HTTP requests.
+ *
+ * @api public
+ */
+class HttpProxyAgent extends agent_base_1.Agent {
+    constructor(_opts) {
+        let opts;
+        if (typeof _opts === 'string') {
+            opts = url_1.default.parse(_opts);
+        }
+        else {
+            opts = _opts;
+        }
+        if (!opts) {
+            throw new Error('an HTTP(S) proxy server `host` and `port` must be specified!');
+        }
+        debug('Creating new HttpProxyAgent instance: %o', opts);
+        super(opts);
+        const proxy = Object.assign({}, opts);
+        // If `true`, then connect to the proxy server over TLS.
+        // Defaults to `false`.
+        this.secureProxy = opts.secureProxy || isHTTPS(proxy.protocol);
+        // Prefer `hostname` over `host`, and set the `port` if needed.
+        proxy.host = proxy.hostname || proxy.host;
+        if (typeof proxy.port === 'string') {
+            proxy.port = parseInt(proxy.port, 10);
+        }
+        if (!proxy.port && proxy.host) {
+            proxy.port = this.secureProxy ? 443 : 80;
+        }
+        if (proxy.host && proxy.path) {
+            // If both a `host` and `path` are specified then it's most likely
+            // the result of a `url.parse()` call... we need to remove the
+            // `path` portion so that `net.connect()` doesn't attempt to open
+            // that as a Unix socket file.
+            delete proxy.path;
+            delete proxy.pathname;
+        }
+        this.proxy = proxy;
+    }
+    /**
+     * Called when the node-core HTTP client library is creating a
+     * new HTTP request.
+     *
+     * @api protected
+     */
+    callback(req, opts) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const { proxy, secureProxy } = this;
+            const parsed = url_1.default.parse(req.path);
+            if (!parsed.protocol) {
+                parsed.protocol = 'http:';
+            }
+            if (!parsed.hostname) {
+                parsed.hostname = opts.hostname || opts.host || null;
+            }
+            if (parsed.port == null && typeof opts.port) {
+                parsed.port = String(opts.port);
+            }
+            if (parsed.port === '80') {
+                // if port is 80, then we can remove the port so that the
+                // ":80" portion is not on the produced URL
+                delete parsed.port;
+            }
+            // Change the `http.ClientRequest` instance's "path" field
+            // to the absolute path of the URL that will be requested.
+            req.path = url_1.default.format(parsed);
+            // Inject the `Proxy-Authorization` header if necessary.
+            if (proxy.auth) {
+                req.setHeader('Proxy-Authorization', `Basic ${Buffer.from(proxy.auth).toString('base64')}`);
+            }
+            // Create a socket connection to the proxy server.
+            let socket;
+            if (secureProxy) {
+                debug('Creating `tls.Socket`: %o', proxy);
+                socket = tls_1.default.connect(proxy);
+            }
+            else {
+                debug('Creating `net.Socket`: %o', proxy);
+                socket = net_1.default.connect(proxy);
+            }
+            // At this point, the http ClientRequest's internal `_header` field
+            // might have already been set. If this is the case then we'll need
+            // to re-generate the string since we just changed the `req.path`.
+            if (req._header) {
+                let first;
+                let endOfHeaders;
+                debug('Regenerating stored HTTP header string for request');
+                req._header = null;
+                req._implicitHeader();
+                if (req.output && req.output.length > 0) {
+                    // Node < 12
+                    debug('Patching connection write() output buffer with updated header');
+                    first = req.output[0];
+                    endOfHeaders = first.indexOf('\r\n\r\n') + 4;
+                    req.output[0] = req._header + first.substring(endOfHeaders);
+                    debug('Output buffer: %o', req.output);
+                }
+                else if (req.outputData && req.outputData.length > 0) {
+                    // Node >= 12
+                    debug('Patching connection write() output buffer with updated header');
+                    first = req.outputData[0].data;
+                    endOfHeaders = first.indexOf('\r\n\r\n') + 4;
+                    req.outputData[0].data =
+                        req._header + first.substring(endOfHeaders);
+                    debug('Output buffer: %o', req.outputData[0].data);
+                }
+            }
+            // Wait for the socket's `connect` event, so that this `callback()`
+            // function throws instead of the `http` request machinery. This is
+            // important for i.e. `PacProxyAgent` which determines a failed proxy
+            // connection via the `callback()` function throwing.
+            yield once_1.default(socket, 'connect');
+            return socket;
+        });
+    }
+}
+exports.default = HttpProxyAgent;
+//# sourceMappingURL=agent.js.map
\ No newline at end of file
diff --git a/server/node_modules/http-proxy-agent/dist/agent.js.map b/server/node_modules/http-proxy-agent/dist/agent.js.map
new file mode 100644
index 0000000..7a40762
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/dist/agent.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"agent.js","sourceRoot":"","sources":["../src/agent.ts"],"names":[],"mappings":";;;;;;;;;;;;;;AAAA,8CAAsB;AACtB,8CAAsB;AACtB,8CAAsB;AACtB,kDAAgC;AAChC,6DAAqC;AACrC,2CAAkE;AAGlE,MAAM,KAAK,GAAG,eAAW,CAAC,kBAAkB,CAAC,CAAC;AAY9C,SAAS,OAAO,CAAC,QAAwB;IACxC,OAAO,OAAO,QAAQ,KAAK,QAAQ,CAAC,CAAC,CAAC,YAAY,CAAC,IAAI,CAAC,QAAQ,CAAC,CAAC,CAAC,CAAC,KAAK,CAAC;AAC3E,CAAC;AAED;;;;;GAKG;AACH,MAAqB,cAAe,SAAQ,kBAAK;IAIhD,YAAY,KAAqC;QAChD,IAAI,IAA2B,CAAC;QAChC,IAAI,OAAO,KAAK,KAAK,QAAQ,EAAE;YAC9B,IAAI,GAAG,aAAG,CAAC,KAAK,CAAC,KAAK,CAAC,CAAC;SACxB;aAAM;YACN,IAAI,GAAG,KAAK,CAAC;SACb;QACD,IAAI,CAAC,IAAI,EAAE;YACV,MAAM,IAAI,KAAK,CACd,8DAA8D,CAC9D,CAAC;SACF;QACD,KAAK,CAAC,0CAA0C,EAAE,IAAI,CAAC,CAAC;QACxD,KAAK,CAAC,IAAI,CAAC,CAAC;QAEZ,MAAM,KAAK,qBAA+B,IAAI,CAAE,CAAC;QAEjD,wDAAwD;QACxD,uBAAuB;QACvB,IAAI,CAAC,WAAW,GAAG,IAAI,CAAC,WAAW,IAAI,OAAO,CAAC,KAAK,CAAC,QAAQ,CAAC,CAAC;QAE/D,+DAA+D;QAC/D,KAAK,CAAC,IAAI,GAAG,KAAK,CAAC,QAAQ,IAAI,KAAK,CAAC,IAAI,CAAC;QAC1C,IAAI,OAAO,KAAK,CAAC,IAAI,KAAK,QAAQ,EAAE;YACnC,KAAK,CAAC,IAAI,GAAG,QAAQ,CAAC,KAAK,CAAC,IAAI,EAAE,EAAE,CAAC,CAAC;SACtC;QACD,IAAI,CAAC,KAAK,CAAC,IAAI,IAAI,KAAK,CAAC,IAAI,EAAE;YAC9B,KAAK,CAAC,IAAI,GAAG,IAAI,CAAC,WAAW,CAAC,CAAC,CAAC,GAAG,CAAC,CAAC,CAAC,EAAE,CAAC;SACzC;QAED,IAAI,KAAK,CAAC,IAAI,IAAI,KAAK,CAAC,IAAI,EAAE;YAC7B,kEAAkE;YAClE,8DAA8D;YAC9D,iEAAiE;YACjE,8BAA8B;YAC9B,OAAO,KAAK,CAAC,IAAI,CAAC;YAClB,OAAO,KAAK,CAAC,QAAQ,CAAC;SACtB;QAED,IAAI,CAAC,KAAK,GAAG,KAAK,CAAC;IACpB,CAAC;IAED;;;;;OAKG;IACG,QAAQ,CACb,GAAgC,EAChC,IAAoB;;YAEpB,MAAM,EAAE,KAAK,EAAE,WAAW,EAAE,GAAG,IAAI,CAAC;YACpC,MAAM,MAAM,GAAG,aAAG,CAAC,KAAK,CAAC,GAAG,CAAC,IAAI,CAAC,CAAC;YAEnC,IAAI,CAAC,MAAM,CAAC,QAAQ,EAAE;gBACrB,MAAM,CAAC,QAAQ,GAAG,OAAO,CAAC;aAC1B;YAED,IAAI,CAAC,MAAM,CAAC,QAAQ,EAAE;gBACrB,MAAM,CAAC,QAAQ,GAAG,IAAI,CAAC,QAAQ,IAAI,IAAI,CAAC,IAAI,IAAI,IAAI,CAAC;aACrD;YAED,IAAI,MAAM,CAAC,IAAI,IAAI,IAAI,IAAI,OAAO,IAAI,CAAC,IAAI,EAAE;gBAC5C,MAAM,CAAC,IAAI,GAAG,MAAM,CAAC,IAAI,CAAC,IAAI,CAAC,CAAC;aAChC;YAED,IAAI,MAAM,CAAC,IAAI,KAAK,IAAI,EAAE;gBACzB,yDAAyD;gBACzD,2CAA2C;gBAC3C,OAAO,MAAM,CAAC,IAAI,CAAC;aACnB;YAED,0DAA0D;YAC1D,0DAA0D;YAC1D,GAAG,CAAC,IAAI,GAAG,aAAG,CAAC,MAAM,CAAC,MAAM,CAAC,CAAC;YAE9B,wDAAwD;YACxD,IAAI,KAAK,CAAC,IAAI,EAAE;gBACf,GAAG,CAAC,SAAS,CACZ,qBAAqB,EACrB,SAAS,MAAM,CAAC,IAAI,CAAC,KAAK,CAAC,IAAI,CAAC,CAAC,QAAQ,CAAC,QAAQ,CAAC,EAAE,CACrD,CAAC;aACF;YAED,kDAAkD;YAClD,IAAI,MAAkB,CAAC;YACvB,IAAI,WAAW,EAAE;gBAChB,KAAK,CAAC,2BAA2B,EAAE,KAAK,CAAC,CAAC;gBAC1C,MAAM,GAAG,aAAG,CAAC,OAAO,CAAC,KAA8B,CAAC,CAAC;aACrD;iBAAM;gBACN,KAAK,CAAC,2BAA2B,EAAE,KAAK,CAAC,CAAC;gBAC1C,MAAM,GAAG,aAAG,CAAC,OAAO,CAAC,KAA2B,CAAC,CAAC;aAClD;YAED,mEAAmE;YACnE,mEAAmE;YACnE,kEAAkE;YAClE,IAAI,GAAG,CAAC,OAAO,EAAE;gBAChB,IAAI,KAAa,CAAC;gBAClB,IAAI,YAAoB,CAAC;gBACzB,KAAK,CAAC,oDAAoD,CAAC,CAAC;gBAC5D,GAAG,CAAC,OAAO,GAAG,IAAI,CAAC;gBACnB,GAAG,CAAC,eAAe,EAAE,CAAC;gBACtB,IAAI,GAAG,CAAC,MAAM,IAAI,GAAG,CAAC,MAAM,CAAC,MAAM,GAAG,CAAC,EAAE;oBACxC,YAAY;oBACZ,KAAK,CACJ,+DAA+D,CAC/D,CAAC;oBACF,KAAK,GAAG,GAAG,CAAC,MAAM,CAAC,CAAC,CAAC,CAAC;oBACtB,YAAY,GAAG,KAAK,CAAC,OAAO,CAAC,UAAU,CAAC,GAAG,CAAC,CAAC;oBAC7C,GAAG,CAAC,MAAM,CAAC,CAAC,CAAC,GAAG,GAAG,CAAC,OAAO,GAAG,KAAK,CAAC,SAAS,CAAC,YAAY,CAAC,CAAC;oBAC5D,KAAK,CAAC,mBAAmB,EAAE,GAAG,CAAC,MAAM,CAAC,CAAC;iBACvC;qBAAM,IAAI,GAAG,CAAC,UAAU,IAAI,GAAG,CAAC,UAAU,CAAC,MAAM,GAAG,CAAC,EAAE;oBACvD,aAAa;oBACb,KAAK,CACJ,+DAA+D,CAC/D,CAAC;oBACF,KAAK,GAAG,GAAG,CAAC,UAAU,CAAC,CAAC,CAAC,CAAC,IAAI,CAAC;oBAC/B,YAAY,GAAG,KAAK,CAAC,OAAO,CAAC,UAAU,CAAC,GAAG,CAAC,CAAC;oBAC7C,GAAG,CAAC,UAAU,CAAC,CAAC,CAAC,CAAC,IAAI;wBACrB,GAAG,CAAC,OAAO,GAAG,KAAK,CAAC,SAAS,CAAC,YAAY,CAAC,CAAC;oBAC7C,KAAK,CAAC,mBAAmB,EAAE,GAAG,CAAC,UAAU,CAAC,CAAC,CAAC,CAAC,IAAI,CAAC,CAAC;iBACnD;aACD;YAED,mEAAmE;YACnE,mEAAmE;YACnE,qEAAqE;YACrE,qDAAqD;YACrD,MAAM,cAAI,CAAC,MAAM,EAAE,SAAS,CAAC,CAAC;YAE9B,OAAO,MAAM,CAAC;QACf,CAAC;KAAA;CACD;AA1ID,iCA0IC"}
\ No newline at end of file
diff --git a/server/node_modules/http-proxy-agent/dist/index.d.ts b/server/node_modules/http-proxy-agent/dist/index.d.ts
new file mode 100644
index 0000000..24bdb52
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/dist/index.d.ts
@@ -0,0 +1,21 @@
+/// <reference types="node" />
+import net from 'net';
+import tls from 'tls';
+import { Url } from 'url';
+import { AgentOptions } from 'agent-base';
+import _HttpProxyAgent from './agent';
+declare function createHttpProxyAgent(opts: string | createHttpProxyAgent.HttpProxyAgentOptions): _HttpProxyAgent;
+declare namespace createHttpProxyAgent {
+    interface BaseHttpProxyAgentOptions {
+        secureProxy?: boolean;
+        host?: string | null;
+        path?: string | null;
+        port?: string | number | null;
+    }
+    export interface HttpProxyAgentOptions extends AgentOptions, BaseHttpProxyAgentOptions, Partial<Omit<Url & net.NetConnectOpts & tls.ConnectionOptions, keyof BaseHttpProxyAgentOptions>> {
+    }
+    export type HttpProxyAgent = _HttpProxyAgent;
+    export const HttpProxyAgent: typeof _HttpProxyAgent;
+    export {};
+}
+export = createHttpProxyAgent;
diff --git a/server/node_modules/http-proxy-agent/dist/index.js b/server/node_modules/http-proxy-agent/dist/index.js
new file mode 100644
index 0000000..0a71180
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/dist/index.js
@@ -0,0 +1,14 @@
+"use strict";
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+const agent_1 = __importDefault(require("./agent"));
+function createHttpProxyAgent(opts) {
+    return new agent_1.default(opts);
+}
+(function (createHttpProxyAgent) {
+    createHttpProxyAgent.HttpProxyAgent = agent_1.default;
+    createHttpProxyAgent.prototype = agent_1.default.prototype;
+})(createHttpProxyAgent || (createHttpProxyAgent = {}));
+module.exports = createHttpProxyAgent;
+//# sourceMappingURL=index.js.map
\ No newline at end of file
diff --git a/server/node_modules/http-proxy-agent/dist/index.js.map b/server/node_modules/http-proxy-agent/dist/index.js.map
new file mode 100644
index 0000000..e07dae5
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/dist/index.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"index.js","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":";;;;AAIA,oDAAsC;AAEtC,SAAS,oBAAoB,CAC5B,IAAyD;IAEzD,OAAO,IAAI,eAAe,CAAC,IAAI,CAAC,CAAC;AAClC,CAAC;AAED,WAAU,oBAAoB;IAmBhB,mCAAc,GAAG,eAAe,CAAC;IAE9C,oBAAoB,CAAC,SAAS,GAAG,eAAe,CAAC,SAAS,CAAC;AAC5D,CAAC,EAtBS,oBAAoB,KAApB,oBAAoB,QAsB7B;AAED,iBAAS,oBAAoB,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/http-proxy-agent/node_modules/debug/LICENSE b/server/node_modules/http-proxy-agent/node_modules/debug/LICENSE
new file mode 100644
index 0000000..1a9820e
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/debug/LICENSE
@@ -0,0 +1,20 @@
+(The MIT License)
+
+Copyright (c) 2014-2017 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2018-2021 Josh Junon
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+and associated documentation files (the 'Software'), to deal in the Software without restriction,
+including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial
+portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
+LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/http-proxy-agent/node_modules/debug/README.md b/server/node_modules/http-proxy-agent/node_modules/debug/README.md
new file mode 100644
index 0000000..9ebdfbf
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/debug/README.md
@@ -0,0 +1,481 @@
+# debug
+[![OpenCollective](https://opencollective.com/debug/backers/badge.svg)](#backers)
+[![OpenCollective](https://opencollective.com/debug/sponsors/badge.svg)](#sponsors)
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091486-fa38524c-7c37-11e7-895f-e7ec8e1039b6.png">
+
+A tiny JavaScript debugging utility modelled after Node.js core's debugging
+technique. Works in Node.js and web browsers.
+
+## Installation
+
+```bash
+$ npm install debug
+```
+
+## Usage
+
+`debug` exposes a function; simply pass this function the name of your module, and it will return a decorated version of `console.error` for you to pass debug statements to. This will allow you to toggle the debug output for different parts of your module as well as the module as a whole.
+
+Example [_app.js_](./examples/node/app.js):
+
+```js
+var debug = require('debug')('http')
+  , http = require('http')
+  , name = 'My App';
+
+// fake app
+
+debug('booting %o', name);
+
+http.createServer(function(req, res){
+  debug(req.method + ' ' + req.url);
+  res.end('hello\n');
+}).listen(3000, function(){
+  debug('listening');
+});
+
+// fake worker of some kind
+
+require('./worker');
+```
+
+Example [_worker.js_](./examples/node/worker.js):
+
+```js
+var a = require('debug')('worker:a')
+  , b = require('debug')('worker:b');
+
+function work() {
+  a('doing lots of uninteresting work');
+  setTimeout(work, Math.random() * 1000);
+}
+
+work();
+
+function workb() {
+  b('doing some work');
+  setTimeout(workb, Math.random() * 2000);
+}
+
+workb();
+```
+
+The `DEBUG` environment variable is then used to enable these based on space or
+comma-delimited names.
+
+Here are some examples:
+
+<img width="647" alt="screen shot 2017-08-08 at 12 53 04 pm" src="https://user-images.githubusercontent.com/71256/29091703-a6302cdc-7c38-11e7-8304-7c0b3bc600cd.png">
+<img width="647" alt="screen shot 2017-08-08 at 12 53 38 pm" src="https://user-images.githubusercontent.com/71256/29091700-a62a6888-7c38-11e7-800b-db911291ca2b.png">
+<img width="647" alt="screen shot 2017-08-08 at 12 53 25 pm" src="https://user-images.githubusercontent.com/71256/29091701-a62ea114-7c38-11e7-826a-2692bedca740.png">
+
+#### Windows command prompt notes
+
+##### CMD
+
+On Windows the environment variable is set using the `set` command.
+
+```cmd
+set DEBUG=*,-not_this
+```
+
+Example:
+
+```cmd
+set DEBUG=* & node app.js
+```
+
+##### PowerShell (VS Code default)
+
+PowerShell uses different syntax to set environment variables.
+
+```cmd
+$env:DEBUG = "*,-not_this"
+```
+
+Example:
+
+```cmd
+$env:DEBUG='app';node app.js
+```
+
+Then, run the program to be debugged as usual.
+
+npm script example:
+```js
+  "windowsDebug": "@powershell -Command $env:DEBUG='*';node app.js",
+```
+
+## Namespace Colors
+
+Every debug instance has a color generated for it based on its namespace name.
+This helps when visually parsing the debug output to identify which debug instance
+a debug line belongs to.
+
+#### Node.js
+
+In Node.js, colors are enabled when stderr is a TTY. You also _should_ install
+the [`supports-color`](https://npmjs.org/supports-color) module alongside debug,
+otherwise debug will only use a small handful of basic colors.
+
+<img width="521" src="https://user-images.githubusercontent.com/71256/29092181-47f6a9e6-7c3a-11e7-9a14-1928d8a711cd.png">
+
+#### Web Browser
+
+Colors are also enabled on "Web Inspectors" that understand the `%c` formatting
+option. These are WebKit web inspectors, Firefox ([since version
+31](https://hacks.mozilla.org/2014/05/editable-box-model-multiple-selection-sublime-text-keys-much-more-firefox-developer-tools-episode-31/))
+and the Firebug plugin for Firefox (any version).
+
+<img width="524" src="https://user-images.githubusercontent.com/71256/29092033-b65f9f2e-7c39-11e7-8e32-f6f0d8e865c1.png">
+
+
+## Millisecond diff
+
+When actively developing an application it can be useful to see when the time spent between one `debug()` call and the next. Suppose for example you invoke `debug()` before requesting a resource, and after as well, the "+NNNms" will show you how much time was spent between calls.
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091486-fa38524c-7c37-11e7-895f-e7ec8e1039b6.png">
+
+When stdout is not a TTY, `Date#toISOString()` is used, making it more useful for logging the debug information as shown below:
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091956-6bd78372-7c39-11e7-8c55-c948396d6edd.png">
+
+
+## Conventions
+
+If you're using this in one or more of your libraries, you _should_ use the name of your library so that developers may toggle debugging as desired without guessing names. If you have more than one debuggers you _should_ prefix them with your library name and use ":" to separate features. For example "bodyParser" from Connect would then be "connect:bodyParser".  If you append a "*" to the end of your name, it will always be enabled regardless of the setting of the DEBUG environment variable.  You can then use it for normal output as well as debug output.
+
+## Wildcards
+
+The `*` character may be used as a wildcard. Suppose for example your library has
+debuggers named "connect:bodyParser", "connect:compress", "connect:session",
+instead of listing all three with
+`DEBUG=connect:bodyParser,connect:compress,connect:session`, you may simply do
+`DEBUG=connect:*`, or to run everything using this module simply use `DEBUG=*`.
+
+You can also exclude specific debuggers by prefixing them with a "-" character.
+For example, `DEBUG=*,-connect:*` would include all debuggers except those
+starting with "connect:".
+
+## Environment Variables
+
+When running through Node.js, you can set a few environment variables that will
+change the behavior of the debug logging:
+
+| Name      | Purpose                                         |
+|-----------|-------------------------------------------------|
+| `DEBUG`   | Enables/disables specific debugging namespaces. |
+| `DEBUG_HIDE_DATE` | Hide date from debug output (non-TTY).  |
+| `DEBUG_COLORS`| Whether or not to use colors in the debug output. |
+| `DEBUG_DEPTH` | Object inspection depth.                    |
+| `DEBUG_SHOW_HIDDEN` | Shows hidden properties on inspected objects. |
+
+
+__Note:__ The environment variables beginning with `DEBUG_` end up being
+converted into an Options object that gets used with `%o`/`%O` formatters.
+See the Node.js documentation for
+[`util.inspect()`](https://nodejs.org/api/util.html#util_util_inspect_object_options)
+for the complete list.
+
+## Formatters
+
+Debug uses [printf-style](https://wikipedia.org/wiki/Printf_format_string) formatting.
+Below are the officially supported formatters:
+
+| Formatter | Representation |
+|-----------|----------------|
+| `%O`      | Pretty-print an Object on multiple lines. |
+| `%o`      | Pretty-print an Object all on a single line. |
+| `%s`      | String. |
+| `%d`      | Number (both integer and float). |
+| `%j`      | JSON. Replaced with the string '[Circular]' if the argument contains circular references. |
+| `%%`      | Single percent sign ('%'). This does not consume an argument. |
+
+
+### Custom formatters
+
+You can add custom formatters by extending the `debug.formatters` object.
+For example, if you wanted to add support for rendering a Buffer as hex with
+`%h`, you could do something like:
+
+```js
+const createDebug = require('debug')
+createDebug.formatters.h = (v) => {
+  return v.toString('hex')
+}
+
+// …elsewhere
+const debug = createDebug('foo')
+debug('this is hex: %h', new Buffer('hello world'))
+//   foo this is hex: 68656c6c6f20776f726c6421 +0ms
+```
+
+
+## Browser Support
+
+You can build a browser-ready script using [browserify](https://github.com/substack/node-browserify),
+or just use the [browserify-as-a-service](https://wzrd.in/) [build](https://wzrd.in/standalone/debug@latest),
+if you don't want to build it yourself.
+
+Debug's enable state is currently persisted by `localStorage`.
+Consider the situation shown below where you have `worker:a` and `worker:b`,
+and wish to debug both. You can enable this using `localStorage.debug`:
+
+```js
+localStorage.debug = 'worker:*'
+```
+
+And then refresh the page.
+
+```js
+a = debug('worker:a');
+b = debug('worker:b');
+
+setInterval(function(){
+  a('doing some work');
+}, 1000);
+
+setInterval(function(){
+  b('doing some work');
+}, 1200);
+```
+
+In Chromium-based web browsers (e.g. Brave, Chrome, and Electron), the JavaScript console will—by default—only show messages logged by `debug` if the "Verbose" log level is _enabled_.
+
+<img width="647" src="https://user-images.githubusercontent.com/7143133/152083257-29034707-c42c-4959-8add-3cee850e6fcf.png">
+
+## Output streams
+
+  By default `debug` will log to stderr, however this can be configured per-namespace by overriding the `log` method:
+
+Example [_stdout.js_](./examples/node/stdout.js):
+
+```js
+var debug = require('debug');
+var error = debug('app:error');
+
+// by default stderr is used
+error('goes to stderr!');
+
+var log = debug('app:log');
+// set this namespace to log via console.log
+log.log = console.log.bind(console); // don't forget to bind to console!
+log('goes to stdout');
+error('still goes to stderr!');
+
+// set all output to go via console.info
+// overrides all per-namespace log settings
+debug.log = console.info.bind(console);
+error('now goes to stdout via console.info');
+log('still goes to stdout, but via console.info now');
+```
+
+## Extend
+You can simply extend debugger 
+```js
+const log = require('debug')('auth');
+
+//creates new debug instance with extended namespace
+const logSign = log.extend('sign');
+const logLogin = log.extend('login');
+
+log('hello'); // auth hello
+logSign('hello'); //auth:sign hello
+logLogin('hello'); //auth:login hello
+```
+
+## Set dynamically
+
+You can also enable debug dynamically by calling the `enable()` method :
+
+```js
+let debug = require('debug');
+
+console.log(1, debug.enabled('test'));
+
+debug.enable('test');
+console.log(2, debug.enabled('test'));
+
+debug.disable();
+console.log(3, debug.enabled('test'));
+
+```
+
+print :   
+```
+1 false
+2 true
+3 false
+```
+
+Usage :  
+`enable(namespaces)`  
+`namespaces` can include modes separated by a colon and wildcards.
+   
+Note that calling `enable()` completely overrides previously set DEBUG variable : 
+
+```
+$ DEBUG=foo node -e 'var dbg = require("debug"); dbg.enable("bar"); console.log(dbg.enabled("foo"))'
+=> false
+```
+
+`disable()`
+
+Will disable all namespaces. The functions returns the namespaces currently
+enabled (and skipped). This can be useful if you want to disable debugging
+temporarily without knowing what was enabled to begin with.
+
+For example:
+
+```js
+let debug = require('debug');
+debug.enable('foo:*,-foo:bar');
+let namespaces = debug.disable();
+debug.enable(namespaces);
+```
+
+Note: There is no guarantee that the string will be identical to the initial
+enable string, but semantically they will be identical.
+
+## Checking whether a debug target is enabled
+
+After you've created a debug instance, you can determine whether or not it is
+enabled by checking the `enabled` property:
+
+```javascript
+const debug = require('debug')('http');
+
+if (debug.enabled) {
+  // do stuff...
+}
+```
+
+You can also manually toggle this property to force the debug instance to be
+enabled or disabled.
+
+## Usage in child processes
+
+Due to the way `debug` detects if the output is a TTY or not, colors are not shown in child processes when `stderr` is piped. A solution is to pass the `DEBUG_COLORS=1` environment variable to the child process.  
+For example:
+
+```javascript
+worker = fork(WORKER_WRAP_PATH, [workerPath], {
+  stdio: [
+    /* stdin: */ 0,
+    /* stdout: */ 'pipe',
+    /* stderr: */ 'pipe',
+    'ipc',
+  ],
+  env: Object.assign({}, process.env, {
+    DEBUG_COLORS: 1 // without this settings, colors won't be shown
+  }),
+});
+
+worker.stderr.pipe(process.stderr, { end: false });
+```
+
+
+## Authors
+
+ - TJ Holowaychuk
+ - Nathan Rajlich
+ - Andrew Rhyne
+ - Josh Junon
+
+## Backers
+
+Support us with a monthly donation and help us continue our activities. [[Become a backer](https://opencollective.com/debug#backer)]
+
+<a href="https://opencollective.com/debug/backer/0/website" target="_blank"><img src="https://opencollective.com/debug/backer/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/1/website" target="_blank"><img src="https://opencollective.com/debug/backer/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/2/website" target="_blank"><img src="https://opencollective.com/debug/backer/2/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/3/website" target="_blank"><img src="https://opencollective.com/debug/backer/3/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/4/website" target="_blank"><img src="https://opencollective.com/debug/backer/4/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/5/website" target="_blank"><img src="https://opencollective.com/debug/backer/5/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/6/website" target="_blank"><img src="https://opencollective.com/debug/backer/6/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/7/website" target="_blank"><img src="https://opencollective.com/debug/backer/7/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/8/website" target="_blank"><img src="https://opencollective.com/debug/backer/8/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/9/website" target="_blank"><img src="https://opencollective.com/debug/backer/9/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/10/website" target="_blank"><img src="https://opencollective.com/debug/backer/10/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/11/website" target="_blank"><img src="https://opencollective.com/debug/backer/11/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/12/website" target="_blank"><img src="https://opencollective.com/debug/backer/12/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/13/website" target="_blank"><img src="https://opencollective.com/debug/backer/13/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/14/website" target="_blank"><img src="https://opencollective.com/debug/backer/14/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/15/website" target="_blank"><img src="https://opencollective.com/debug/backer/15/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/16/website" target="_blank"><img src="https://opencollective.com/debug/backer/16/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/17/website" target="_blank"><img src="https://opencollective.com/debug/backer/17/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/18/website" target="_blank"><img src="https://opencollective.com/debug/backer/18/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/19/website" target="_blank"><img src="https://opencollective.com/debug/backer/19/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/20/website" target="_blank"><img src="https://opencollective.com/debug/backer/20/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/21/website" target="_blank"><img src="https://opencollective.com/debug/backer/21/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/22/website" target="_blank"><img src="https://opencollective.com/debug/backer/22/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/23/website" target="_blank"><img src="https://opencollective.com/debug/backer/23/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/24/website" target="_blank"><img src="https://opencollective.com/debug/backer/24/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/25/website" target="_blank"><img src="https://opencollective.com/debug/backer/25/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/26/website" target="_blank"><img src="https://opencollective.com/debug/backer/26/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/27/website" target="_blank"><img src="https://opencollective.com/debug/backer/27/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/28/website" target="_blank"><img src="https://opencollective.com/debug/backer/28/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/29/website" target="_blank"><img src="https://opencollective.com/debug/backer/29/avatar.svg"></a>
+
+
+## Sponsors
+
+Become a sponsor and get your logo on our README on Github with a link to your site. [[Become a sponsor](https://opencollective.com/debug#sponsor)]
+
+<a href="https://opencollective.com/debug/sponsor/0/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/1/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/2/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/2/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/3/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/3/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/4/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/4/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/5/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/5/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/6/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/6/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/7/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/7/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/8/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/8/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/9/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/9/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/10/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/10/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/11/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/11/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/12/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/12/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/13/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/13/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/14/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/14/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/15/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/15/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/16/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/16/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/17/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/17/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/18/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/18/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/19/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/19/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/20/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/20/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/21/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/21/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/22/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/22/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/23/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/23/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/24/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/24/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/25/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/25/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/26/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/26/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/27/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/27/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/28/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/28/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/29/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/29/avatar.svg"></a>
+
+## License
+
+(The MIT License)
+
+Copyright (c) 2014-2017 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2018-2021 Josh Junon
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/http-proxy-agent/node_modules/debug/package.json b/server/node_modules/http-proxy-agent/node_modules/debug/package.json
new file mode 100644
index 0000000..ee8abb5
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/debug/package.json
@@ -0,0 +1,64 @@
+{
+  "name": "debug",
+  "version": "4.4.3",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/debug-js/debug.git"
+  },
+  "description": "Lightweight debugging utility for Node.js and the browser",
+  "keywords": [
+    "debug",
+    "log",
+    "debugger"
+  ],
+  "files": [
+    "src",
+    "LICENSE",
+    "README.md"
+  ],
+  "author": "Josh Junon (https://github.com/qix-)",
+  "contributors": [
+    "TJ Holowaychuk <tj@vision-media.ca>",
+    "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io)",
+    "Andrew Rhyne <rhyneandrew@gmail.com>"
+  ],
+  "license": "MIT",
+  "scripts": {
+    "lint": "xo",
+    "test": "npm run test:node && npm run test:browser && npm run lint",
+    "test:node": "mocha test.js test.node.js",
+    "test:browser": "karma start --single-run",
+    "test:coverage": "cat ./coverage/lcov.info | coveralls"
+  },
+  "dependencies": {
+    "ms": "^2.1.3"
+  },
+  "devDependencies": {
+    "brfs": "^2.0.1",
+    "browserify": "^16.2.3",
+    "coveralls": "^3.0.2",
+    "karma": "^3.1.4",
+    "karma-browserify": "^6.0.0",
+    "karma-chrome-launcher": "^2.2.0",
+    "karma-mocha": "^1.3.0",
+    "mocha": "^5.2.0",
+    "mocha-lcov-reporter": "^1.2.0",
+    "sinon": "^14.0.0",
+    "xo": "^0.23.0"
+  },
+  "peerDependenciesMeta": {
+    "supports-color": {
+      "optional": true
+    }
+  },
+  "main": "./src/index.js",
+  "browser": "./src/browser.js",
+  "engines": {
+    "node": ">=6.0"
+  },
+  "xo": {
+    "rules": {
+      "import/extensions": "off"
+    }
+  }
+}
diff --git a/server/node_modules/http-proxy-agent/node_modules/debug/src/browser.js b/server/node_modules/http-proxy-agent/node_modules/debug/src/browser.js
new file mode 100644
index 0000000..5993451
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/debug/src/browser.js
@@ -0,0 +1,272 @@
+/* eslint-env browser */
+
+/**
+ * This is the web browser implementation of `debug()`.
+ */
+
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+exports.storage = localstorage();
+exports.destroy = (() => {
+	let warned = false;
+
+	return () => {
+		if (!warned) {
+			warned = true;
+			console.warn('Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.');
+		}
+	};
+})();
+
+/**
+ * Colors.
+ */
+
+exports.colors = [
+	'#0000CC',
+	'#0000FF',
+	'#0033CC',
+	'#0033FF',
+	'#0066CC',
+	'#0066FF',
+	'#0099CC',
+	'#0099FF',
+	'#00CC00',
+	'#00CC33',
+	'#00CC66',
+	'#00CC99',
+	'#00CCCC',
+	'#00CCFF',
+	'#3300CC',
+	'#3300FF',
+	'#3333CC',
+	'#3333FF',
+	'#3366CC',
+	'#3366FF',
+	'#3399CC',
+	'#3399FF',
+	'#33CC00',
+	'#33CC33',
+	'#33CC66',
+	'#33CC99',
+	'#33CCCC',
+	'#33CCFF',
+	'#6600CC',
+	'#6600FF',
+	'#6633CC',
+	'#6633FF',
+	'#66CC00',
+	'#66CC33',
+	'#9900CC',
+	'#9900FF',
+	'#9933CC',
+	'#9933FF',
+	'#99CC00',
+	'#99CC33',
+	'#CC0000',
+	'#CC0033',
+	'#CC0066',
+	'#CC0099',
+	'#CC00CC',
+	'#CC00FF',
+	'#CC3300',
+	'#CC3333',
+	'#CC3366',
+	'#CC3399',
+	'#CC33CC',
+	'#CC33FF',
+	'#CC6600',
+	'#CC6633',
+	'#CC9900',
+	'#CC9933',
+	'#CCCC00',
+	'#CCCC33',
+	'#FF0000',
+	'#FF0033',
+	'#FF0066',
+	'#FF0099',
+	'#FF00CC',
+	'#FF00FF',
+	'#FF3300',
+	'#FF3333',
+	'#FF3366',
+	'#FF3399',
+	'#FF33CC',
+	'#FF33FF',
+	'#FF6600',
+	'#FF6633',
+	'#FF9900',
+	'#FF9933',
+	'#FFCC00',
+	'#FFCC33'
+];
+
+/**
+ * Currently only WebKit-based Web Inspectors, Firefox >= v31,
+ * and the Firebug extension (any Firefox version) are known
+ * to support "%c" CSS customizations.
+ *
+ * TODO: add a `localStorage` variable to explicitly enable/disable colors
+ */
+
+// eslint-disable-next-line complexity
+function useColors() {
+	// NB: In an Electron preload script, document will be defined but not fully
+	// initialized. Since we know we're in Chrome, we'll just detect this case
+	// explicitly
+	if (typeof window !== 'undefined' && window.process && (window.process.type === 'renderer' || window.process.__nwjs)) {
+		return true;
+	}
+
+	// Internet Explorer and Edge do not support colors.
+	if (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/(edge|trident)\/(\d+)/)) {
+		return false;
+	}
+
+	let m;
+
+	// Is webkit? http://stackoverflow.com/a/16459606/376773
+	// document is undefined in react-native: https://github.com/facebook/react-native/pull/1632
+	// eslint-disable-next-line no-return-assign
+	return (typeof document !== 'undefined' && document.documentElement && document.documentElement.style && document.documentElement.style.WebkitAppearance) ||
+		// Is firebug? http://stackoverflow.com/a/398120/376773
+		(typeof window !== 'undefined' && window.console && (window.console.firebug || (window.console.exception && window.console.table))) ||
+		// Is firefox >= v31?
+		// https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
+		(typeof navigator !== 'undefined' && navigator.userAgent && (m = navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/)) && parseInt(m[1], 10) >= 31) ||
+		// Double check webkit in userAgent just in case we are in a worker
+		(typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/applewebkit\/(\d+)/));
+}
+
+/**
+ * Colorize log arguments if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+	args[0] = (this.useColors ? '%c' : '') +
+		this.namespace +
+		(this.useColors ? ' %c' : ' ') +
+		args[0] +
+		(this.useColors ? '%c ' : ' ') +
+		'+' + module.exports.humanize(this.diff);
+
+	if (!this.useColors) {
+		return;
+	}
+
+	const c = 'color: ' + this.color;
+	args.splice(1, 0, c, 'color: inherit');
+
+	// The final "%c" is somewhat tricky, because there could be other
+	// arguments passed either before or after the %c, so we need to
+	// figure out the correct index to insert the CSS into
+	let index = 0;
+	let lastC = 0;
+	args[0].replace(/%[a-zA-Z%]/g, match => {
+		if (match === '%%') {
+			return;
+		}
+		index++;
+		if (match === '%c') {
+			// We only are interested in the *last* %c
+			// (the user may have provided their own)
+			lastC = index;
+		}
+	});
+
+	args.splice(lastC, 0, c);
+}
+
+/**
+ * Invokes `console.debug()` when available.
+ * No-op when `console.debug` is not a "function".
+ * If `console.debug` is not available, falls back
+ * to `console.log`.
+ *
+ * @api public
+ */
+exports.log = console.debug || console.log || (() => {});
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+function save(namespaces) {
+	try {
+		if (namespaces) {
+			exports.storage.setItem('debug', namespaces);
+		} else {
+			exports.storage.removeItem('debug');
+		}
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+function load() {
+	let r;
+	try {
+		r = exports.storage.getItem('debug') || exports.storage.getItem('DEBUG') ;
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+
+	// If debug isn't set in LS, and we're in Electron, try to load $DEBUG
+	if (!r && typeof process !== 'undefined' && 'env' in process) {
+		r = process.env.DEBUG;
+	}
+
+	return r;
+}
+
+/**
+ * Localstorage attempts to return the localstorage.
+ *
+ * This is necessary because safari throws
+ * when a user disables cookies/localstorage
+ * and you attempt to access it.
+ *
+ * @return {LocalStorage}
+ * @api private
+ */
+
+function localstorage() {
+	try {
+		// TVMLKit (Apple TV JS Runtime) does not have a window object, just localStorage in the global context
+		// The Browser also has localStorage in the global context.
+		return localStorage;
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+}
+
+module.exports = require('./common')(exports);
+
+const {formatters} = module.exports;
+
+/**
+ * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
+ */
+
+formatters.j = function (v) {
+	try {
+		return JSON.stringify(v);
+	} catch (error) {
+		return '[UnexpectedJSONParseError]: ' + error.message;
+	}
+};
diff --git a/server/node_modules/http-proxy-agent/node_modules/debug/src/common.js b/server/node_modules/http-proxy-agent/node_modules/debug/src/common.js
new file mode 100644
index 0000000..141cb57
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/debug/src/common.js
@@ -0,0 +1,292 @@
+
+/**
+ * This is the common logic for both the Node.js and web browser
+ * implementations of `debug()`.
+ */
+
+function setup(env) {
+	createDebug.debug = createDebug;
+	createDebug.default = createDebug;
+	createDebug.coerce = coerce;
+	createDebug.disable = disable;
+	createDebug.enable = enable;
+	createDebug.enabled = enabled;
+	createDebug.humanize = require('ms');
+	createDebug.destroy = destroy;
+
+	Object.keys(env).forEach(key => {
+		createDebug[key] = env[key];
+	});
+
+	/**
+	* The currently active debug mode names, and names to skip.
+	*/
+
+	createDebug.names = [];
+	createDebug.skips = [];
+
+	/**
+	* Map of special "%n" handling functions, for the debug "format" argument.
+	*
+	* Valid key names are a single, lower or upper-case letter, i.e. "n" and "N".
+	*/
+	createDebug.formatters = {};
+
+	/**
+	* Selects a color for a debug namespace
+	* @param {String} namespace The namespace string for the debug instance to be colored
+	* @return {Number|String} An ANSI color code for the given namespace
+	* @api private
+	*/
+	function selectColor(namespace) {
+		let hash = 0;
+
+		for (let i = 0; i < namespace.length; i++) {
+			hash = ((hash << 5) - hash) + namespace.charCodeAt(i);
+			hash |= 0; // Convert to 32bit integer
+		}
+
+		return createDebug.colors[Math.abs(hash) % createDebug.colors.length];
+	}
+	createDebug.selectColor = selectColor;
+
+	/**
+	* Create a debugger with the given `namespace`.
+	*
+	* @param {String} namespace
+	* @return {Function}
+	* @api public
+	*/
+	function createDebug(namespace) {
+		let prevTime;
+		let enableOverride = null;
+		let namespacesCache;
+		let enabledCache;
+
+		function debug(...args) {
+			// Disabled?
+			if (!debug.enabled) {
+				return;
+			}
+
+			const self = debug;
+
+			// Set `diff` timestamp
+			const curr = Number(new Date());
+			const ms = curr - (prevTime || curr);
+			self.diff = ms;
+			self.prev = prevTime;
+			self.curr = curr;
+			prevTime = curr;
+
+			args[0] = createDebug.coerce(args[0]);
+
+			if (typeof args[0] !== 'string') {
+				// Anything else let's inspect with %O
+				args.unshift('%O');
+			}
+
+			// Apply any `formatters` transformations
+			let index = 0;
+			args[0] = args[0].replace(/%([a-zA-Z%])/g, (match, format) => {
+				// If we encounter an escaped % then don't increase the array index
+				if (match === '%%') {
+					return '%';
+				}
+				index++;
+				const formatter = createDebug.formatters[format];
+				if (typeof formatter === 'function') {
+					const val = args[index];
+					match = formatter.call(self, val);
+
+					// Now we need to remove `args[index]` since it's inlined in the `format`
+					args.splice(index, 1);
+					index--;
+				}
+				return match;
+			});
+
+			// Apply env-specific formatting (colors, etc.)
+			createDebug.formatArgs.call(self, args);
+
+			const logFn = self.log || createDebug.log;
+			logFn.apply(self, args);
+		}
+
+		debug.namespace = namespace;
+		debug.useColors = createDebug.useColors();
+		debug.color = createDebug.selectColor(namespace);
+		debug.extend = extend;
+		debug.destroy = createDebug.destroy; // XXX Temporary. Will be removed in the next major release.
+
+		Object.defineProperty(debug, 'enabled', {
+			enumerable: true,
+			configurable: false,
+			get: () => {
+				if (enableOverride !== null) {
+					return enableOverride;
+				}
+				if (namespacesCache !== createDebug.namespaces) {
+					namespacesCache = createDebug.namespaces;
+					enabledCache = createDebug.enabled(namespace);
+				}
+
+				return enabledCache;
+			},
+			set: v => {
+				enableOverride = v;
+			}
+		});
+
+		// Env-specific initialization logic for debug instances
+		if (typeof createDebug.init === 'function') {
+			createDebug.init(debug);
+		}
+
+		return debug;
+	}
+
+	function extend(namespace, delimiter) {
+		const newDebug = createDebug(this.namespace + (typeof delimiter === 'undefined' ? ':' : delimiter) + namespace);
+		newDebug.log = this.log;
+		return newDebug;
+	}
+
+	/**
+	* Enables a debug mode by namespaces. This can include modes
+	* separated by a colon and wildcards.
+	*
+	* @param {String} namespaces
+	* @api public
+	*/
+	function enable(namespaces) {
+		createDebug.save(namespaces);
+		createDebug.namespaces = namespaces;
+
+		createDebug.names = [];
+		createDebug.skips = [];
+
+		const split = (typeof namespaces === 'string' ? namespaces : '')
+			.trim()
+			.replace(/\s+/g, ',')
+			.split(',')
+			.filter(Boolean);
+
+		for (const ns of split) {
+			if (ns[0] === '-') {
+				createDebug.skips.push(ns.slice(1));
+			} else {
+				createDebug.names.push(ns);
+			}
+		}
+	}
+
+	/**
+	 * Checks if the given string matches a namespace template, honoring
+	 * asterisks as wildcards.
+	 *
+	 * @param {String} search
+	 * @param {String} template
+	 * @return {Boolean}
+	 */
+	function matchesTemplate(search, template) {
+		let searchIndex = 0;
+		let templateIndex = 0;
+		let starIndex = -1;
+		let matchIndex = 0;
+
+		while (searchIndex < search.length) {
+			if (templateIndex < template.length && (template[templateIndex] === search[searchIndex] || template[templateIndex] === '*')) {
+				// Match character or proceed with wildcard
+				if (template[templateIndex] === '*') {
+					starIndex = templateIndex;
+					matchIndex = searchIndex;
+					templateIndex++; // Skip the '*'
+				} else {
+					searchIndex++;
+					templateIndex++;
+				}
+			} else if (starIndex !== -1) { // eslint-disable-line no-negated-condition
+				// Backtrack to the last '*' and try to match more characters
+				templateIndex = starIndex + 1;
+				matchIndex++;
+				searchIndex = matchIndex;
+			} else {
+				return false; // No match
+			}
+		}
+
+		// Handle trailing '*' in template
+		while (templateIndex < template.length && template[templateIndex] === '*') {
+			templateIndex++;
+		}
+
+		return templateIndex === template.length;
+	}
+
+	/**
+	* Disable debug output.
+	*
+	* @return {String} namespaces
+	* @api public
+	*/
+	function disable() {
+		const namespaces = [
+			...createDebug.names,
+			...createDebug.skips.map(namespace => '-' + namespace)
+		].join(',');
+		createDebug.enable('');
+		return namespaces;
+	}
+
+	/**
+	* Returns true if the given mode name is enabled, false otherwise.
+	*
+	* @param {String} name
+	* @return {Boolean}
+	* @api public
+	*/
+	function enabled(name) {
+		for (const skip of createDebug.skips) {
+			if (matchesTemplate(name, skip)) {
+				return false;
+			}
+		}
+
+		for (const ns of createDebug.names) {
+			if (matchesTemplate(name, ns)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	* Coerce `val`.
+	*
+	* @param {Mixed} val
+	* @return {Mixed}
+	* @api private
+	*/
+	function coerce(val) {
+		if (val instanceof Error) {
+			return val.stack || val.message;
+		}
+		return val;
+	}
+
+	/**
+	* XXX DO NOT USE. This is a temporary stub function.
+	* XXX It WILL be removed in the next major release.
+	*/
+	function destroy() {
+		console.warn('Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.');
+	}
+
+	createDebug.enable(createDebug.load());
+
+	return createDebug;
+}
+
+module.exports = setup;
diff --git a/server/node_modules/http-proxy-agent/node_modules/debug/src/index.js b/server/node_modules/http-proxy-agent/node_modules/debug/src/index.js
new file mode 100644
index 0000000..bf4c57f
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/debug/src/index.js
@@ -0,0 +1,10 @@
+/**
+ * Detect Electron renderer / nwjs process, which is node, but we should
+ * treat as a browser.
+ */
+
+if (typeof process === 'undefined' || process.type === 'renderer' || process.browser === true || process.__nwjs) {
+	module.exports = require('./browser.js');
+} else {
+	module.exports = require('./node.js');
+}
diff --git a/server/node_modules/http-proxy-agent/node_modules/debug/src/node.js b/server/node_modules/http-proxy-agent/node_modules/debug/src/node.js
new file mode 100644
index 0000000..715560a
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/debug/src/node.js
@@ -0,0 +1,263 @@
+/**
+ * Module dependencies.
+ */
+
+const tty = require('tty');
+const util = require('util');
+
+/**
+ * This is the Node.js implementation of `debug()`.
+ */
+
+exports.init = init;
+exports.log = log;
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+exports.destroy = util.deprecate(
+	() => {},
+	'Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.'
+);
+
+/**
+ * Colors.
+ */
+
+exports.colors = [6, 2, 3, 4, 5, 1];
+
+try {
+	// Optional dependency (as in, doesn't need to be installed, NOT like optionalDependencies in package.json)
+	// eslint-disable-next-line import/no-extraneous-dependencies
+	const supportsColor = require('supports-color');
+
+	if (supportsColor && (supportsColor.stderr || supportsColor).level >= 2) {
+		exports.colors = [
+			20,
+			21,
+			26,
+			27,
+			32,
+			33,
+			38,
+			39,
+			40,
+			41,
+			42,
+			43,
+			44,
+			45,
+			56,
+			57,
+			62,
+			63,
+			68,
+			69,
+			74,
+			75,
+			76,
+			77,
+			78,
+			79,
+			80,
+			81,
+			92,
+			93,
+			98,
+			99,
+			112,
+			113,
+			128,
+			129,
+			134,
+			135,
+			148,
+			149,
+			160,
+			161,
+			162,
+			163,
+			164,
+			165,
+			166,
+			167,
+			168,
+			169,
+			170,
+			171,
+			172,
+			173,
+			178,
+			179,
+			184,
+			185,
+			196,
+			197,
+			198,
+			199,
+			200,
+			201,
+			202,
+			203,
+			204,
+			205,
+			206,
+			207,
+			208,
+			209,
+			214,
+			215,
+			220,
+			221
+		];
+	}
+} catch (error) {
+	// Swallow - we only care if `supports-color` is available; it doesn't have to be.
+}
+
+/**
+ * Build up the default `inspectOpts` object from the environment variables.
+ *
+ *   $ DEBUG_COLORS=no DEBUG_DEPTH=10 DEBUG_SHOW_HIDDEN=enabled node script.js
+ */
+
+exports.inspectOpts = Object.keys(process.env).filter(key => {
+	return /^debug_/i.test(key);
+}).reduce((obj, key) => {
+	// Camel-case
+	const prop = key
+		.substring(6)
+		.toLowerCase()
+		.replace(/_([a-z])/g, (_, k) => {
+			return k.toUpperCase();
+		});
+
+	// Coerce string value into JS value
+	let val = process.env[key];
+	if (/^(yes|on|true|enabled)$/i.test(val)) {
+		val = true;
+	} else if (/^(no|off|false|disabled)$/i.test(val)) {
+		val = false;
+	} else if (val === 'null') {
+		val = null;
+	} else {
+		val = Number(val);
+	}
+
+	obj[prop] = val;
+	return obj;
+}, {});
+
+/**
+ * Is stdout a TTY? Colored output is enabled when `true`.
+ */
+
+function useColors() {
+	return 'colors' in exports.inspectOpts ?
+		Boolean(exports.inspectOpts.colors) :
+		tty.isatty(process.stderr.fd);
+}
+
+/**
+ * Adds ANSI color escape codes if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+	const {namespace: name, useColors} = this;
+
+	if (useColors) {
+		const c = this.color;
+		const colorCode = '\u001B[3' + (c < 8 ? c : '8;5;' + c);
+		const prefix = `  ${colorCode};1m${name} \u001B[0m`;
+
+		args[0] = prefix + args[0].split('\n').join('\n' + prefix);
+		args.push(colorCode + 'm+' + module.exports.humanize(this.diff) + '\u001B[0m');
+	} else {
+		args[0] = getDate() + name + ' ' + args[0];
+	}
+}
+
+function getDate() {
+	if (exports.inspectOpts.hideDate) {
+		return '';
+	}
+	return new Date().toISOString() + ' ';
+}
+
+/**
+ * Invokes `util.formatWithOptions()` with the specified arguments and writes to stderr.
+ */
+
+function log(...args) {
+	return process.stderr.write(util.formatWithOptions(exports.inspectOpts, ...args) + '\n');
+}
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+function save(namespaces) {
+	if (namespaces) {
+		process.env.DEBUG = namespaces;
+	} else {
+		// If you set a process.env field to null or undefined, it gets cast to the
+		// string 'null' or 'undefined'. Just delete instead.
+		delete process.env.DEBUG;
+	}
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+
+function load() {
+	return process.env.DEBUG;
+}
+
+/**
+ * Init logic for `debug` instances.
+ *
+ * Create a new `inspectOpts` object in case `useColors` is set
+ * differently for a particular `debug` instance.
+ */
+
+function init(debug) {
+	debug.inspectOpts = {};
+
+	const keys = Object.keys(exports.inspectOpts);
+	for (let i = 0; i < keys.length; i++) {
+		debug.inspectOpts[keys[i]] = exports.inspectOpts[keys[i]];
+	}
+}
+
+module.exports = require('./common')(exports);
+
+const {formatters} = module.exports;
+
+/**
+ * Map %o to `util.inspect()`, all on a single line.
+ */
+
+formatters.o = function (v) {
+	this.inspectOpts.colors = this.useColors;
+	return util.inspect(v, this.inspectOpts)
+		.split('\n')
+		.map(str => str.trim())
+		.join(' ');
+};
+
+/**
+ * Map %O to `util.inspect()`, allowing multiple lines if needed.
+ */
+
+formatters.O = function (v) {
+	this.inspectOpts.colors = this.useColors;
+	return util.inspect(v, this.inspectOpts);
+};
diff --git a/server/node_modules/http-proxy-agent/node_modules/ms/index.js b/server/node_modules/http-proxy-agent/node_modules/ms/index.js
new file mode 100644
index 0000000..ea734fb
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/ms/index.js
@@ -0,0 +1,162 @@
+/**
+ * Helpers.
+ */
+
+var s = 1000;
+var m = s * 60;
+var h = m * 60;
+var d = h * 24;
+var w = d * 7;
+var y = d * 365.25;
+
+/**
+ * Parse or format the given `val`.
+ *
+ * Options:
+ *
+ *  - `long` verbose formatting [false]
+ *
+ * @param {String|Number} val
+ * @param {Object} [options]
+ * @throws {Error} throw an error if val is not a non-empty string or a number
+ * @return {String|Number}
+ * @api public
+ */
+
+module.exports = function (val, options) {
+  options = options || {};
+  var type = typeof val;
+  if (type === 'string' && val.length > 0) {
+    return parse(val);
+  } else if (type === 'number' && isFinite(val)) {
+    return options.long ? fmtLong(val) : fmtShort(val);
+  }
+  throw new Error(
+    'val is not a non-empty string or a valid number. val=' +
+      JSON.stringify(val)
+  );
+};
+
+/**
+ * Parse the given `str` and return milliseconds.
+ *
+ * @param {String} str
+ * @return {Number}
+ * @api private
+ */
+
+function parse(str) {
+  str = String(str);
+  if (str.length > 100) {
+    return;
+  }
+  var match = /^(-?(?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|weeks?|w|years?|yrs?|y)?$/i.exec(
+    str
+  );
+  if (!match) {
+    return;
+  }
+  var n = parseFloat(match[1]);
+  var type = (match[2] || 'ms').toLowerCase();
+  switch (type) {
+    case 'years':
+    case 'year':
+    case 'yrs':
+    case 'yr':
+    case 'y':
+      return n * y;
+    case 'weeks':
+    case 'week':
+    case 'w':
+      return n * w;
+    case 'days':
+    case 'day':
+    case 'd':
+      return n * d;
+    case 'hours':
+    case 'hour':
+    case 'hrs':
+    case 'hr':
+    case 'h':
+      return n * h;
+    case 'minutes':
+    case 'minute':
+    case 'mins':
+    case 'min':
+    case 'm':
+      return n * m;
+    case 'seconds':
+    case 'second':
+    case 'secs':
+    case 'sec':
+    case 's':
+      return n * s;
+    case 'milliseconds':
+    case 'millisecond':
+    case 'msecs':
+    case 'msec':
+    case 'ms':
+      return n;
+    default:
+      return undefined;
+  }
+}
+
+/**
+ * Short format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtShort(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return Math.round(ms / d) + 'd';
+  }
+  if (msAbs >= h) {
+    return Math.round(ms / h) + 'h';
+  }
+  if (msAbs >= m) {
+    return Math.round(ms / m) + 'm';
+  }
+  if (msAbs >= s) {
+    return Math.round(ms / s) + 's';
+  }
+  return ms + 'ms';
+}
+
+/**
+ * Long format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtLong(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return plural(ms, msAbs, d, 'day');
+  }
+  if (msAbs >= h) {
+    return plural(ms, msAbs, h, 'hour');
+  }
+  if (msAbs >= m) {
+    return plural(ms, msAbs, m, 'minute');
+  }
+  if (msAbs >= s) {
+    return plural(ms, msAbs, s, 'second');
+  }
+  return ms + ' ms';
+}
+
+/**
+ * Pluralization helper.
+ */
+
+function plural(ms, msAbs, n, name) {
+  var isPlural = msAbs >= n * 1.5;
+  return Math.round(ms / n) + ' ' + name + (isPlural ? 's' : '');
+}
diff --git a/server/node_modules/http-proxy-agent/node_modules/ms/license.md b/server/node_modules/http-proxy-agent/node_modules/ms/license.md
new file mode 100644
index 0000000..fa5d39b
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/ms/license.md
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2020 Vercel, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/http-proxy-agent/node_modules/ms/package.json b/server/node_modules/http-proxy-agent/node_modules/ms/package.json
new file mode 100644
index 0000000..4997189
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/ms/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "ms",
+  "version": "2.1.3",
+  "description": "Tiny millisecond conversion utility",
+  "repository": "vercel/ms",
+  "main": "./index",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "precommit": "lint-staged",
+    "lint": "eslint lib/* bin/*",
+    "test": "mocha tests.js"
+  },
+  "eslintConfig": {
+    "extends": "eslint:recommended",
+    "env": {
+      "node": true,
+      "es6": true
+    }
+  },
+  "lint-staged": {
+    "*.js": [
+      "npm run lint",
+      "prettier --single-quote --write",
+      "git add"
+    ]
+  },
+  "license": "MIT",
+  "devDependencies": {
+    "eslint": "4.18.2",
+    "expect.js": "0.3.1",
+    "husky": "0.14.3",
+    "lint-staged": "5.0.0",
+    "mocha": "4.0.1",
+    "prettier": "2.0.5"
+  }
+}
diff --git a/server/node_modules/http-proxy-agent/node_modules/ms/readme.md b/server/node_modules/http-proxy-agent/node_modules/ms/readme.md
new file mode 100644
index 0000000..0fc1abb
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/node_modules/ms/readme.md
@@ -0,0 +1,59 @@
+# ms
+
+![CI](https://github.com/vercel/ms/workflows/CI/badge.svg)
+
+Use this package to easily convert various time formats to milliseconds.
+
+## Examples
+
+```js
+ms('2 days')  // 172800000
+ms('1d')      // 86400000
+ms('10h')     // 36000000
+ms('2.5 hrs') // 9000000
+ms('2h')      // 7200000
+ms('1m')      // 60000
+ms('5s')      // 5000
+ms('1y')      // 31557600000
+ms('100')     // 100
+ms('-3 days') // -259200000
+ms('-1h')     // -3600000
+ms('-200')    // -200
+```
+
+### Convert from Milliseconds
+
+```js
+ms(60000)             // "1m"
+ms(2 * 60000)         // "2m"
+ms(-3 * 60000)        // "-3m"
+ms(ms('10 hours'))    // "10h"
+```
+
+### Time Format Written-Out
+
+```js
+ms(60000, { long: true })             // "1 minute"
+ms(2 * 60000, { long: true })         // "2 minutes"
+ms(-3 * 60000, { long: true })        // "-3 minutes"
+ms(ms('10 hours'), { long: true })    // "10 hours"
+```
+
+## Features
+
+- Works both in [Node.js](https://nodejs.org) and in the browser
+- If a number is supplied to `ms`, a string with a unit is returned
+- If a string that contains the number is supplied, it returns it as a number (e.g.: it returns `100` for `'100'`)
+- If you pass a string with a number and a valid unit, the number of equivalent milliseconds is returned
+
+## Related Packages
+
+- [ms.macro](https://github.com/knpwrs/ms.macro) - Run `ms` as a macro at build-time.
+
+## Caught a Bug?
+
+1. [Fork](https://help.github.com/articles/fork-a-repo/) this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device
+2. Link the package to the global module directory: `npm link`
+3. Within the module you want to test your local development instance of ms, just link it to the dependencies: `npm link ms`. Instead of the default one from npm, Node.js will now use your clone of ms!
+
+As always, you can run the tests using: `npm test`
diff --git a/server/node_modules/http-proxy-agent/package.json b/server/node_modules/http-proxy-agent/package.json
new file mode 100644
index 0000000..870dd5d
--- /dev/null
+++ b/server/node_modules/http-proxy-agent/package.json
@@ -0,0 +1,57 @@
+{
+  "name": "http-proxy-agent",
+  "version": "4.0.1",
+  "description": "An HTTP(s) proxy `http.Agent` implementation for HTTP",
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "prebuild": "rimraf dist",
+    "build": "tsc",
+    "test": "mocha",
+    "test-lint": "eslint src --ext .js,.ts",
+    "prepublishOnly": "npm run build"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/TooTallNate/node-http-proxy-agent.git"
+  },
+  "keywords": [
+    "http",
+    "proxy",
+    "endpoint",
+    "agent"
+  ],
+  "author": "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io/)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/TooTallNate/node-http-proxy-agent/issues"
+  },
+  "dependencies": {
+    "@tootallnate/once": "1",
+    "agent-base": "6",
+    "debug": "4"
+  },
+  "devDependencies": {
+    "@types/debug": "4",
+    "@types/node": "^12.12.11",
+    "@typescript-eslint/eslint-plugin": "1.6.0",
+    "@typescript-eslint/parser": "1.1.0",
+    "eslint": "5.16.0",
+    "eslint-config-airbnb": "17.1.0",
+    "eslint-config-prettier": "4.1.0",
+    "eslint-import-resolver-typescript": "1.1.1",
+    "eslint-plugin-import": "2.16.0",
+    "eslint-plugin-jsx-a11y": "6.2.1",
+    "eslint-plugin-react": "7.12.4",
+    "mocha": "^6.2.2",
+    "proxy": "1",
+    "rimraf": "^3.0.0",
+    "typescript": "^3.5.3"
+  },
+  "engines": {
+    "node": ">= 6"
+  }
+}
diff --git a/server/node_modules/https-proxy-agent/README.md b/server/node_modules/https-proxy-agent/README.md
new file mode 100644
index 0000000..328656a
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/README.md
@@ -0,0 +1,137 @@
+https-proxy-agent
+================
+### An HTTP(s) proxy `http.Agent` implementation for HTTPS
+[![Build Status](https://github.com/TooTallNate/node-https-proxy-agent/workflows/Node%20CI/badge.svg)](https://github.com/TooTallNate/node-https-proxy-agent/actions?workflow=Node+CI)
+
+This module provides an `http.Agent` implementation that connects to a specified
+HTTP or HTTPS proxy server, and can be used with the built-in `https` module.
+
+Specifically, this `Agent` implementation connects to an intermediary "proxy"
+server and issues the [CONNECT HTTP method][CONNECT], which tells the proxy to
+open a direct TCP connection to the destination server.
+
+Since this agent implements the CONNECT HTTP method, it also works with other
+protocols that use this method when connecting over proxies (i.e. WebSockets).
+See the "Examples" section below for more.
+
+
+Installation
+------------
+
+Install with `npm`:
+
+``` bash
+$ npm install https-proxy-agent
+```
+
+
+Examples
+--------
+
+#### `https` module example
+
+``` js
+var url = require('url');
+var https = require('https');
+var HttpsProxyAgent = require('https-proxy-agent');
+
+// HTTP/HTTPS proxy to connect to
+var proxy = process.env.http_proxy || 'http://168.63.76.32:3128';
+console.log('using proxy server %j', proxy);
+
+// HTTPS endpoint for the proxy to connect to
+var endpoint = process.argv[2] || 'https://graph.facebook.com/tootallnate';
+console.log('attempting to GET %j', endpoint);
+var options = url.parse(endpoint);
+
+// create an instance of the `HttpsProxyAgent` class with the proxy server information
+var agent = new HttpsProxyAgent(proxy);
+options.agent = agent;
+
+https.get(options, function (res) {
+  console.log('"response" event!', res.headers);
+  res.pipe(process.stdout);
+});
+```
+
+#### `ws` WebSocket connection example
+
+``` js
+var url = require('url');
+var WebSocket = require('ws');
+var HttpsProxyAgent = require('https-proxy-agent');
+
+// HTTP/HTTPS proxy to connect to
+var proxy = process.env.http_proxy || 'http://168.63.76.32:3128';
+console.log('using proxy server %j', proxy);
+
+// WebSocket endpoint for the proxy to connect to
+var endpoint = process.argv[2] || 'ws://echo.websocket.org';
+var parsed = url.parse(endpoint);
+console.log('attempting to connect to WebSocket %j', endpoint);
+
+// create an instance of the `HttpsProxyAgent` class with the proxy server information
+var options = url.parse(proxy);
+
+var agent = new HttpsProxyAgent(options);
+
+// finally, initiate the WebSocket connection
+var socket = new WebSocket(endpoint, { agent: agent });
+
+socket.on('open', function () {
+  console.log('"open" event!');
+  socket.send('hello world');
+});
+
+socket.on('message', function (data, flags) {
+  console.log('"message" event! %j %j', data, flags);
+  socket.close();
+});
+```
+
+API
+---
+
+### new HttpsProxyAgent(Object options)
+
+The `HttpsProxyAgent` class implements an `http.Agent` subclass that connects
+to the specified "HTTP(s) proxy server" in order to proxy HTTPS and/or WebSocket
+requests. This is achieved by using the [HTTP `CONNECT` method][CONNECT].
+
+The `options` argument may either be a string URI of the proxy server to use, or an
+"options" object with more specific properties:
+
+  * `host` - String - Proxy host to connect to (may use `hostname` as well). Required.
+  * `port` - Number - Proxy port to connect to. Required.
+  * `protocol` - String - If `https:`, then use TLS to connect to the proxy.
+  * `headers` - Object - Additional HTTP headers to be sent on the HTTP CONNECT method.
+  * Any other options given are passed to the `net.connect()`/`tls.connect()` functions.
+
+
+License
+-------
+
+(The MIT License)
+
+Copyright (c) 2013 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+[CONNECT]: http://en.wikipedia.org/wiki/HTTP_tunnel#HTTP_CONNECT_Tunneling
diff --git a/server/node_modules/https-proxy-agent/dist/agent.d.ts b/server/node_modules/https-proxy-agent/dist/agent.d.ts
new file mode 100644
index 0000000..4f1c636
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/dist/agent.d.ts
@@ -0,0 +1,30 @@
+/// <reference types="node" />
+import net from 'net';
+import { Agent, ClientRequest, RequestOptions } from 'agent-base';
+import { HttpsProxyAgentOptions } from '.';
+/**
+ * The `HttpsProxyAgent` implements an HTTP Agent subclass that connects to
+ * the specified "HTTP(s) proxy server" in order to proxy HTTPS requests.
+ *
+ * Outgoing HTTP requests are first tunneled through the proxy server using the
+ * `CONNECT` HTTP request method to establish a connection to the proxy server,
+ * and then the proxy server connects to the destination target and issues the
+ * HTTP request from the proxy server.
+ *
+ * `https:` requests have their socket connection upgraded to TLS once
+ * the connection to the proxy server has been established.
+ *
+ * @api public
+ */
+export default class HttpsProxyAgent extends Agent {
+    private secureProxy;
+    private proxy;
+    constructor(_opts: string | HttpsProxyAgentOptions);
+    /**
+     * Called when the node-core HTTP client library is creating a
+     * new HTTP request.
+     *
+     * @api protected
+     */
+    callback(req: ClientRequest, opts: RequestOptions): Promise<net.Socket>;
+}
diff --git a/server/node_modules/https-proxy-agent/dist/agent.js b/server/node_modules/https-proxy-agent/dist/agent.js
new file mode 100644
index 0000000..75d1136
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/dist/agent.js
@@ -0,0 +1,177 @@
+"use strict";
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+const net_1 = __importDefault(require("net"));
+const tls_1 = __importDefault(require("tls"));
+const url_1 = __importDefault(require("url"));
+const assert_1 = __importDefault(require("assert"));
+const debug_1 = __importDefault(require("debug"));
+const agent_base_1 = require("agent-base");
+const parse_proxy_response_1 = __importDefault(require("./parse-proxy-response"));
+const debug = debug_1.default('https-proxy-agent:agent');
+/**
+ * The `HttpsProxyAgent` implements an HTTP Agent subclass that connects to
+ * the specified "HTTP(s) proxy server" in order to proxy HTTPS requests.
+ *
+ * Outgoing HTTP requests are first tunneled through the proxy server using the
+ * `CONNECT` HTTP request method to establish a connection to the proxy server,
+ * and then the proxy server connects to the destination target and issues the
+ * HTTP request from the proxy server.
+ *
+ * `https:` requests have their socket connection upgraded to TLS once
+ * the connection to the proxy server has been established.
+ *
+ * @api public
+ */
+class HttpsProxyAgent extends agent_base_1.Agent {
+    constructor(_opts) {
+        let opts;
+        if (typeof _opts === 'string') {
+            opts = url_1.default.parse(_opts);
+        }
+        else {
+            opts = _opts;
+        }
+        if (!opts) {
+            throw new Error('an HTTP(S) proxy server `host` and `port` must be specified!');
+        }
+        debug('creating new HttpsProxyAgent instance: %o', opts);
+        super(opts);
+        const proxy = Object.assign({}, opts);
+        // If `true`, then connect to the proxy server over TLS.
+        // Defaults to `false`.
+        this.secureProxy = opts.secureProxy || isHTTPS(proxy.protocol);
+        // Prefer `hostname` over `host`, and set the `port` if needed.
+        proxy.host = proxy.hostname || proxy.host;
+        if (typeof proxy.port === 'string') {
+            proxy.port = parseInt(proxy.port, 10);
+        }
+        if (!proxy.port && proxy.host) {
+            proxy.port = this.secureProxy ? 443 : 80;
+        }
+        // ALPN is supported by Node.js >= v5.
+        // attempt to negotiate http/1.1 for proxy servers that support http/2
+        if (this.secureProxy && !('ALPNProtocols' in proxy)) {
+            proxy.ALPNProtocols = ['http 1.1'];
+        }
+        if (proxy.host && proxy.path) {
+            // If both a `host` and `path` are specified then it's most likely
+            // the result of a `url.parse()` call... we need to remove the
+            // `path` portion so that `net.connect()` doesn't attempt to open
+            // that as a Unix socket file.
+            delete proxy.path;
+            delete proxy.pathname;
+        }
+        this.proxy = proxy;
+    }
+    /**
+     * Called when the node-core HTTP client library is creating a
+     * new HTTP request.
+     *
+     * @api protected
+     */
+    callback(req, opts) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const { proxy, secureProxy } = this;
+            // Create a socket connection to the proxy server.
+            let socket;
+            if (secureProxy) {
+                debug('Creating `tls.Socket`: %o', proxy);
+                socket = tls_1.default.connect(proxy);
+            }
+            else {
+                debug('Creating `net.Socket`: %o', proxy);
+                socket = net_1.default.connect(proxy);
+            }
+            const headers = Object.assign({}, proxy.headers);
+            const hostname = `${opts.host}:${opts.port}`;
+            let payload = `CONNECT ${hostname} HTTP/1.1\r\n`;
+            // Inject the `Proxy-Authorization` header if necessary.
+            if (proxy.auth) {
+                headers['Proxy-Authorization'] = `Basic ${Buffer.from(proxy.auth).toString('base64')}`;
+            }
+            // The `Host` header should only include the port
+            // number when it is not the default port.
+            let { host, port, secureEndpoint } = opts;
+            if (!isDefaultPort(port, secureEndpoint)) {
+                host += `:${port}`;
+            }
+            headers.Host = host;
+            headers.Connection = 'close';
+            for (const name of Object.keys(headers)) {
+                payload += `${name}: ${headers[name]}\r\n`;
+            }
+            const proxyResponsePromise = parse_proxy_response_1.default(socket);
+            socket.write(`${payload}\r\n`);
+            const { statusCode, buffered } = yield proxyResponsePromise;
+            if (statusCode === 200) {
+                req.once('socket', resume);
+                if (opts.secureEndpoint) {
+                    // The proxy is connecting to a TLS server, so upgrade
+                    // this socket connection to a TLS connection.
+                    debug('Upgrading socket connection to TLS');
+                    const servername = opts.servername || opts.host;
+                    return tls_1.default.connect(Object.assign(Object.assign({}, omit(opts, 'host', 'hostname', 'path', 'port')), { socket,
+                        servername }));
+                }
+                return socket;
+            }
+            // Some other status code that's not 200... need to re-play the HTTP
+            // header "data" events onto the socket once the HTTP machinery is
+            // attached so that the node core `http` can parse and handle the
+            // error status code.
+            // Close the original socket, and a new "fake" socket is returned
+            // instead, so that the proxy doesn't get the HTTP request
+            // written to it (which may contain `Authorization` headers or other
+            // sensitive data).
+            //
+            // See: https://hackerone.com/reports/541502
+            socket.destroy();
+            const fakeSocket = new net_1.default.Socket({ writable: false });
+            fakeSocket.readable = true;
+            // Need to wait for the "socket" event to re-play the "data" events.
+            req.once('socket', (s) => {
+                debug('replaying proxy buffer for failed request');
+                assert_1.default(s.listenerCount('data') > 0);
+                // Replay the "buffered" Buffer onto the fake `socket`, since at
+                // this point the HTTP module machinery has been hooked up for
+                // the user.
+                s.push(buffered);
+                s.push(null);
+            });
+            return fakeSocket;
+        });
+    }
+}
+exports.default = HttpsProxyAgent;
+function resume(socket) {
+    socket.resume();
+}
+function isDefaultPort(port, secure) {
+    return Boolean((!secure && port === 80) || (secure && port === 443));
+}
+function isHTTPS(protocol) {
+    return typeof protocol === 'string' ? /^https:?$/i.test(protocol) : false;
+}
+function omit(obj, ...keys) {
+    const ret = {};
+    let key;
+    for (key in obj) {
+        if (!keys.includes(key)) {
+            ret[key] = obj[key];
+        }
+    }
+    return ret;
+}
+//# sourceMappingURL=agent.js.map
\ No newline at end of file
diff --git a/server/node_modules/https-proxy-agent/dist/agent.js.map b/server/node_modules/https-proxy-agent/dist/agent.js.map
new file mode 100644
index 0000000..0af6c17
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/dist/agent.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"agent.js","sourceRoot":"","sources":["../src/agent.ts"],"names":[],"mappings":";;;;;;;;;;;;;;AAAA,8CAAsB;AACtB,8CAAsB;AACtB,8CAAsB;AACtB,oDAA4B;AAC5B,kDAAgC;AAEhC,2CAAkE;AAElE,kFAAwD;AAExD,MAAM,KAAK,GAAG,eAAW,CAAC,yBAAyB,CAAC,CAAC;AAErD;;;;;;;;;;;;;GAaG;AACH,MAAqB,eAAgB,SAAQ,kBAAK;IAIjD,YAAY,KAAsC;QACjD,IAAI,IAA4B,CAAC;QACjC,IAAI,OAAO,KAAK,KAAK,QAAQ,EAAE;YAC9B,IAAI,GAAG,aAAG,CAAC,KAAK,CAAC,KAAK,CAAC,CAAC;SACxB;aAAM;YACN,IAAI,GAAG,KAAK,CAAC;SACb;QACD,IAAI,CAAC,IAAI,EAAE;YACV,MAAM,IAAI,KAAK,CACd,8DAA8D,CAC9D,CAAC;SACF;QACD,KAAK,CAAC,2CAA2C,EAAE,IAAI,CAAC,CAAC;QACzD,KAAK,CAAC,IAAI,CAAC,CAAC;QAEZ,MAAM,KAAK,qBAAgC,IAAI,CAAE,CAAC;QAElD,wDAAwD;QACxD,uBAAuB;QACvB,IAAI,CAAC,WAAW,GAAG,IAAI,CAAC,WAAW,IAAI,OAAO,CAAC,KAAK,CAAC,QAAQ,CAAC,CAAC;QAE/D,+DAA+D;QAC/D,KAAK,CAAC,IAAI,GAAG,KAAK,CAAC,QAAQ,IAAI,KAAK,CAAC,IAAI,CAAC;QAC1C,IAAI,OAAO,KAAK,CAAC,IAAI,KAAK,QAAQ,EAAE;YACnC,KAAK,CAAC,IAAI,GAAG,QAAQ,CAAC,KAAK,CAAC,IAAI,EAAE,EAAE,CAAC,CAAC;SACtC;QACD,IAAI,CAAC,KAAK,CAAC,IAAI,IAAI,KAAK,CAAC,IAAI,EAAE;YAC9B,KAAK,CAAC,IAAI,GAAG,IAAI,CAAC,WAAW,CAAC,CAAC,CAAC,GAAG,CAAC,CAAC,CAAC,EAAE,CAAC;SACzC;QAED,sCAAsC;QACtC,sEAAsE;QACtE,IAAI,IAAI,CAAC,WAAW,IAAI,CAAC,CAAC,eAAe,IAAI,KAAK,CAAC,EAAE;YACpD,KAAK,CAAC,aAAa,GAAG,CAAC,UAAU,CAAC,CAAC;SACnC;QAED,IAAI,KAAK,CAAC,IAAI,IAAI,KAAK,CAAC,IAAI,EAAE;YAC7B,kEAAkE;YAClE,8DAA8D;YAC9D,iEAAiE;YACjE,8BAA8B;YAC9B,OAAO,KAAK,CAAC,IAAI,CAAC;YAClB,OAAO,KAAK,CAAC,QAAQ,CAAC;SACtB;QAED,IAAI,CAAC,KAAK,GAAG,KAAK,CAAC;IACpB,CAAC;IAED;;;;;OAKG;IACG,QAAQ,CACb,GAAkB,EAClB,IAAoB;;YAEpB,MAAM,EAAE,KAAK,EAAE,WAAW,EAAE,GAAG,IAAI,CAAC;YAEpC,kDAAkD;YAClD,IAAI,MAAkB,CAAC;YACvB,IAAI,WAAW,EAAE;gBAChB,KAAK,CAAC,2BAA2B,EAAE,KAAK,CAAC,CAAC;gBAC1C,MAAM,GAAG,aAAG,CAAC,OAAO,CAAC,KAA8B,CAAC,CAAC;aACrD;iBAAM;gBACN,KAAK,CAAC,2BAA2B,EAAE,KAAK,CAAC,CAAC;gBAC1C,MAAM,GAAG,aAAG,CAAC,OAAO,CAAC,KAA2B,CAAC,CAAC;aAClD;YAED,MAAM,OAAO,qBAA6B,KAAK,CAAC,OAAO,CAAE,CAAC;YAC1D,MAAM,QAAQ,GAAG,GAAG,IAAI,CAAC,IAAI,IAAI,IAAI,CAAC,IAAI,EAAE,CAAC;YAC7C,IAAI,OAAO,GAAG,WAAW,QAAQ,eAAe,CAAC;YAEjD,wDAAwD;YACxD,IAAI,KAAK,CAAC,IAAI,EAAE;gBACf,OAAO,CAAC,qBAAqB,CAAC,GAAG,SAAS,MAAM,CAAC,IAAI,CACpD,KAAK,CAAC,IAAI,CACV,CAAC,QAAQ,CAAC,QAAQ,CAAC,EAAE,CAAC;aACvB;YAED,iDAAiD;YACjD,0CAA0C;YAC1C,IAAI,EAAE,IAAI,EAAE,IAAI,EAAE,cAAc,EAAE,GAAG,IAAI,CAAC;YAC1C,IAAI,CAAC,aAAa,CAAC,IAAI,EAAE,cAAc,CAAC,EAAE;gBACzC,IAAI,IAAI,IAAI,IAAI,EAAE,CAAC;aACnB;YACD,OAAO,CAAC,IAAI,GAAG,IAAI,CAAC;YAEpB,OAAO,CAAC,UAAU,GAAG,OAAO,CAAC;YAC7B,KAAK,MAAM,IAAI,IAAI,MAAM,CAAC,IAAI,CAAC,OAAO,CAAC,EAAE;gBACxC,OAAO,IAAI,GAAG,IAAI,KAAK,OAAO,CAAC,IAAI,CAAC,MAAM,CAAC;aAC3C;YAED,MAAM,oBAAoB,GAAG,8BAAkB,CAAC,MAAM,CAAC,CAAC;YAExD,MAAM,CAAC,KAAK,CAAC,GAAG,OAAO,MAAM,CAAC,CAAC;YAE/B,MAAM,EACL,UAAU,EACV,QAAQ,EACR,GAAG,MAAM,oBAAoB,CAAC;YAE/B,IAAI,UAAU,KAAK,GAAG,EAAE;gBACvB,GAAG,CAAC,IAAI,CAAC,QAAQ,EAAE,MAAM,CAAC,CAAC;gBAE3B,IAAI,IAAI,CAAC,cAAc,EAAE;oBACxB,sDAAsD;oBACtD,8CAA8C;oBAC9C,KAAK,CAAC,oCAAoC,CAAC,CAAC;oBAC5C,MAAM,UAAU,GAAG,IAAI,CAAC,UAAU,IAAI,IAAI,CAAC,IAAI,CAAC;oBAChD,OAAO,aAAG,CAAC,OAAO,iCACd,IAAI,CAAC,IAAI,EAAE,MAAM,EAAE,UAAU,EAAE,MAAM,EAAE,MAAM,CAAC,KACjD,MAAM;wBACN,UAAU,IACT,CAAC;iBACH;gBAED,OAAO,MAAM,CAAC;aACd;YAED,oEAAoE;YACpE,kEAAkE;YAClE,iEAAiE;YACjE,qBAAqB;YAErB,iEAAiE;YACjE,0DAA0D;YAC1D,oEAAoE;YACpE,mBAAmB;YACnB,EAAE;YACF,4CAA4C;YAC5C,MAAM,CAAC,OAAO,EAAE,CAAC;YAEjB,MAAM,UAAU,GAAG,IAAI,aAAG,CAAC,MAAM,CAAC,EAAE,QAAQ,EAAE,KAAK,EAAE,CAAC,CAAC;YACvD,UAAU,CAAC,QAAQ,GAAG,IAAI,CAAC;YAE3B,oEAAoE;YACpE,GAAG,CAAC,IAAI,CAAC,QAAQ,EAAE,CAAC,CAAa,EAAE,EAAE;gBACpC,KAAK,CAAC,2CAA2C,CAAC,CAAC;gBACnD,gBAAM,CAAC,CAAC,CAAC,aAAa,CAAC,MAAM,CAAC,GAAG,CAAC,CAAC,CAAC;gBAEpC,gEAAgE;gBAChE,8DAA8D;gBAC9D,YAAY;gBACZ,CAAC,CAAC,IAAI,CAAC,QAAQ,CAAC,CAAC;gBACjB,CAAC,CAAC,IAAI,CAAC,IAAI,CAAC,CAAC;YACd,CAAC,CAAC,CAAC;YAEH,OAAO,UAAU,CAAC;QACnB,CAAC;KAAA;CACD;AA3JD,kCA2JC;AAED,SAAS,MAAM,CAAC,MAAkC;IACjD,MAAM,CAAC,MAAM,EAAE,CAAC;AACjB,CAAC;AAED,SAAS,aAAa,CAAC,IAAY,EAAE,MAAe;IACnD,OAAO,OAAO,CAAC,CAAC,CAAC,MAAM,IAAI,IAAI,KAAK,EAAE,CAAC,IAAI,CAAC,MAAM,IAAI,IAAI,KAAK,GAAG,CAAC,CAAC,CAAC;AACtE,CAAC;AAED,SAAS,OAAO,CAAC,QAAwB;IACxC,OAAO,OAAO,QAAQ,KAAK,QAAQ,CAAC,CAAC,CAAC,YAAY,CAAC,IAAI,CAAC,QAAQ,CAAC,CAAC,CAAC,CAAC,KAAK,CAAC;AAC3E,CAAC;AAED,SAAS,IAAI,CACZ,GAAM,EACN,GAAG,IAAO;IAIV,MAAM,GAAG,GAAG,EAEX,CAAC;IACF,IAAI,GAAqB,CAAC;IAC1B,KAAK,GAAG,IAAI,GAAG,EAAE;QAChB,IAAI,CAAC,IAAI,CAAC,QAAQ,CAAC,GAAG,CAAC,EAAE;YACxB,GAAG,CAAC,GAAG,CAAC,GAAG,GAAG,CAAC,GAAG,CAAC,CAAC;SACpB;KACD;IACD,OAAO,GAAG,CAAC;AACZ,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/https-proxy-agent/dist/index.d.ts b/server/node_modules/https-proxy-agent/dist/index.d.ts
new file mode 100644
index 0000000..0d60062
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/dist/index.d.ts
@@ -0,0 +1,23 @@
+/// <reference types="node" />
+import net from 'net';
+import tls from 'tls';
+import { Url } from 'url';
+import { AgentOptions } from 'agent-base';
+import { OutgoingHttpHeaders } from 'http';
+import _HttpsProxyAgent from './agent';
+declare function createHttpsProxyAgent(opts: string | createHttpsProxyAgent.HttpsProxyAgentOptions): _HttpsProxyAgent;
+declare namespace createHttpsProxyAgent {
+    interface BaseHttpsProxyAgentOptions {
+        headers?: OutgoingHttpHeaders;
+        secureProxy?: boolean;
+        host?: string | null;
+        path?: string | null;
+        port?: string | number | null;
+    }
+    export interface HttpsProxyAgentOptions extends AgentOptions, BaseHttpsProxyAgentOptions, Partial<Omit<Url & net.NetConnectOpts & tls.ConnectionOptions, keyof BaseHttpsProxyAgentOptions>> {
+    }
+    export type HttpsProxyAgent = _HttpsProxyAgent;
+    export const HttpsProxyAgent: typeof _HttpsProxyAgent;
+    export {};
+}
+export = createHttpsProxyAgent;
diff --git a/server/node_modules/https-proxy-agent/dist/index.js b/server/node_modules/https-proxy-agent/dist/index.js
new file mode 100644
index 0000000..b03e763
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/dist/index.js
@@ -0,0 +1,14 @@
+"use strict";
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+const agent_1 = __importDefault(require("./agent"));
+function createHttpsProxyAgent(opts) {
+    return new agent_1.default(opts);
+}
+(function (createHttpsProxyAgent) {
+    createHttpsProxyAgent.HttpsProxyAgent = agent_1.default;
+    createHttpsProxyAgent.prototype = agent_1.default.prototype;
+})(createHttpsProxyAgent || (createHttpsProxyAgent = {}));
+module.exports = createHttpsProxyAgent;
+//# sourceMappingURL=index.js.map
\ No newline at end of file
diff --git a/server/node_modules/https-proxy-agent/dist/index.js.map b/server/node_modules/https-proxy-agent/dist/index.js.map
new file mode 100644
index 0000000..f3ce559
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/dist/index.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"index.js","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":";;;;AAKA,oDAAuC;AAEvC,SAAS,qBAAqB,CAC7B,IAA2D;IAE3D,OAAO,IAAI,eAAgB,CAAC,IAAI,CAAC,CAAC;AACnC,CAAC;AAED,WAAU,qBAAqB;IAoBjB,qCAAe,GAAG,eAAgB,CAAC;IAEhD,qBAAqB,CAAC,SAAS,GAAG,eAAgB,CAAC,SAAS,CAAC;AAC9D,CAAC,EAvBS,qBAAqB,KAArB,qBAAqB,QAuB9B;AAED,iBAAS,qBAAqB,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/https-proxy-agent/dist/parse-proxy-response.d.ts b/server/node_modules/https-proxy-agent/dist/parse-proxy-response.d.ts
new file mode 100644
index 0000000..7565674
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/dist/parse-proxy-response.d.ts
@@ -0,0 +1,7 @@
+/// <reference types="node" />
+import { Readable } from 'stream';
+export interface ProxyResponse {
+    statusCode: number;
+    buffered: Buffer;
+}
+export default function parseProxyResponse(socket: Readable): Promise<ProxyResponse>;
diff --git a/server/node_modules/https-proxy-agent/dist/parse-proxy-response.js b/server/node_modules/https-proxy-agent/dist/parse-proxy-response.js
new file mode 100644
index 0000000..aa5ce3c
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/dist/parse-proxy-response.js
@@ -0,0 +1,66 @@
+"use strict";
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+const debug_1 = __importDefault(require("debug"));
+const debug = debug_1.default('https-proxy-agent:parse-proxy-response');
+function parseProxyResponse(socket) {
+    return new Promise((resolve, reject) => {
+        // we need to buffer any HTTP traffic that happens with the proxy before we get
+        // the CONNECT response, so that if the response is anything other than an "200"
+        // response code, then we can re-play the "data" events on the socket once the
+        // HTTP parser is hooked up...
+        let buffersLength = 0;
+        const buffers = [];
+        function read() {
+            const b = socket.read();
+            if (b)
+                ondata(b);
+            else
+                socket.once('readable', read);
+        }
+        function cleanup() {
+            socket.removeListener('end', onend);
+            socket.removeListener('error', onerror);
+            socket.removeListener('close', onclose);
+            socket.removeListener('readable', read);
+        }
+        function onclose(err) {
+            debug('onclose had error %o', err);
+        }
+        function onend() {
+            debug('onend');
+        }
+        function onerror(err) {
+            cleanup();
+            debug('onerror %o', err);
+            reject(err);
+        }
+        function ondata(b) {
+            buffers.push(b);
+            buffersLength += b.length;
+            const buffered = Buffer.concat(buffers, buffersLength);
+            const endOfHeaders = buffered.indexOf('\r\n\r\n');
+            if (endOfHeaders === -1) {
+                // keep buffering
+                debug('have not received end of HTTP headers yet...');
+                read();
+                return;
+            }
+            const firstLine = buffered.toString('ascii', 0, buffered.indexOf('\r\n'));
+            const statusCode = +firstLine.split(' ')[1];
+            debug('got proxy server response: %o', firstLine);
+            resolve({
+                statusCode,
+                buffered
+            });
+        }
+        socket.on('error', onerror);
+        socket.on('close', onclose);
+        socket.on('end', onend);
+        read();
+    });
+}
+exports.default = parseProxyResponse;
+//# sourceMappingURL=parse-proxy-response.js.map
\ No newline at end of file
diff --git a/server/node_modules/https-proxy-agent/dist/parse-proxy-response.js.map b/server/node_modules/https-proxy-agent/dist/parse-proxy-response.js.map
new file mode 100644
index 0000000..bacdb84
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/dist/parse-proxy-response.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"parse-proxy-response.js","sourceRoot":"","sources":["../src/parse-proxy-response.ts"],"names":[],"mappings":";;;;;AAAA,kDAAgC;AAGhC,MAAM,KAAK,GAAG,eAAW,CAAC,wCAAwC,CAAC,CAAC;AAOpE,SAAwB,kBAAkB,CACzC,MAAgB;IAEhB,OAAO,IAAI,OAAO,CAAC,CAAC,OAAO,EAAE,MAAM,EAAE,EAAE;QACtC,+EAA+E;QAC/E,gFAAgF;QAChF,8EAA8E;QAC9E,8BAA8B;QAC9B,IAAI,aAAa,GAAG,CAAC,CAAC;QACtB,MAAM,OAAO,GAAa,EAAE,CAAC;QAE7B,SAAS,IAAI;YACZ,MAAM,CAAC,GAAG,MAAM,CAAC,IAAI,EAAE,CAAC;YACxB,IAAI,CAAC;gBAAE,MAAM,CAAC,CAAC,CAAC,CAAC;;gBACZ,MAAM,CAAC,IAAI,CAAC,UAAU,EAAE,IAAI,CAAC,CAAC;QACpC,CAAC;QAED,SAAS,OAAO;YACf,MAAM,CAAC,cAAc,CAAC,KAAK,EAAE,KAAK,CAAC,CAAC;YACpC,MAAM,CAAC,cAAc,CAAC,OAAO,EAAE,OAAO,CAAC,CAAC;YACxC,MAAM,CAAC,cAAc,CAAC,OAAO,EAAE,OAAO,CAAC,CAAC;YACxC,MAAM,CAAC,cAAc,CAAC,UAAU,EAAE,IAAI,CAAC,CAAC;QACzC,CAAC;QAED,SAAS,OAAO,CAAC,GAAW;YAC3B,KAAK,CAAC,sBAAsB,EAAE,GAAG,CAAC,CAAC;QACpC,CAAC;QAED,SAAS,KAAK;YACb,KAAK,CAAC,OAAO,CAAC,CAAC;QAChB,CAAC;QAED,SAAS,OAAO,CAAC,GAAU;YAC1B,OAAO,EAAE,CAAC;YACV,KAAK,CAAC,YAAY,EAAE,GAAG,CAAC,CAAC;YACzB,MAAM,CAAC,GAAG,CAAC,CAAC;QACb,CAAC;QAED,SAAS,MAAM,CAAC,CAAS;YACxB,OAAO,CAAC,IAAI,CAAC,CAAC,CAAC,CAAC;YAChB,aAAa,IAAI,CAAC,CAAC,MAAM,CAAC;YAE1B,MAAM,QAAQ,GAAG,MAAM,CAAC,MAAM,CAAC,OAAO,EAAE,aAAa,CAAC,CAAC;YACvD,MAAM,YAAY,GAAG,QAAQ,CAAC,OAAO,CAAC,UAAU,CAAC,CAAC;YAElD,IAAI,YAAY,KAAK,CAAC,CAAC,EAAE;gBACxB,iBAAiB;gBACjB,KAAK,CAAC,8CAA8C,CAAC,CAAC;gBACtD,IAAI,EAAE,CAAC;gBACP,OAAO;aACP;YAED,MAAM,SAAS,GAAG,QAAQ,CAAC,QAAQ,CAClC,OAAO,EACP,CAAC,EACD,QAAQ,CAAC,OAAO,CAAC,MAAM,CAAC,CACxB,CAAC;YACF,MAAM,UAAU,GAAG,CAAC,SAAS,CAAC,KAAK,CAAC,GAAG,CAAC,CAAC,CAAC,CAAC,CAAC;YAC5C,KAAK,CAAC,+BAA+B,EAAE,SAAS,CAAC,CAAC;YAClD,OAAO,CAAC;gBACP,UAAU;gBACV,QAAQ;aACR,CAAC,CAAC;QACJ,CAAC;QAED,MAAM,CAAC,EAAE,CAAC,OAAO,EAAE,OAAO,CAAC,CAAC;QAC5B,MAAM,CAAC,EAAE,CAAC,OAAO,EAAE,OAAO,CAAC,CAAC;QAC5B,MAAM,CAAC,EAAE,CAAC,KAAK,EAAE,KAAK,CAAC,CAAC;QAExB,IAAI,EAAE,CAAC;IACR,CAAC,CAAC,CAAC;AACJ,CAAC;AAvED,qCAuEC"}
\ No newline at end of file
diff --git a/server/node_modules/https-proxy-agent/node_modules/debug/LICENSE b/server/node_modules/https-proxy-agent/node_modules/debug/LICENSE
new file mode 100644
index 0000000..1a9820e
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/debug/LICENSE
@@ -0,0 +1,20 @@
+(The MIT License)
+
+Copyright (c) 2014-2017 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2018-2021 Josh Junon
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+and associated documentation files (the 'Software'), to deal in the Software without restriction,
+including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial
+portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
+LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/https-proxy-agent/node_modules/debug/README.md b/server/node_modules/https-proxy-agent/node_modules/debug/README.md
new file mode 100644
index 0000000..9ebdfbf
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/debug/README.md
@@ -0,0 +1,481 @@
+# debug
+[![OpenCollective](https://opencollective.com/debug/backers/badge.svg)](#backers)
+[![OpenCollective](https://opencollective.com/debug/sponsors/badge.svg)](#sponsors)
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091486-fa38524c-7c37-11e7-895f-e7ec8e1039b6.png">
+
+A tiny JavaScript debugging utility modelled after Node.js core's debugging
+technique. Works in Node.js and web browsers.
+
+## Installation
+
+```bash
+$ npm install debug
+```
+
+## Usage
+
+`debug` exposes a function; simply pass this function the name of your module, and it will return a decorated version of `console.error` for you to pass debug statements to. This will allow you to toggle the debug output for different parts of your module as well as the module as a whole.
+
+Example [_app.js_](./examples/node/app.js):
+
+```js
+var debug = require('debug')('http')
+  , http = require('http')
+  , name = 'My App';
+
+// fake app
+
+debug('booting %o', name);
+
+http.createServer(function(req, res){
+  debug(req.method + ' ' + req.url);
+  res.end('hello\n');
+}).listen(3000, function(){
+  debug('listening');
+});
+
+// fake worker of some kind
+
+require('./worker');
+```
+
+Example [_worker.js_](./examples/node/worker.js):
+
+```js
+var a = require('debug')('worker:a')
+  , b = require('debug')('worker:b');
+
+function work() {
+  a('doing lots of uninteresting work');
+  setTimeout(work, Math.random() * 1000);
+}
+
+work();
+
+function workb() {
+  b('doing some work');
+  setTimeout(workb, Math.random() * 2000);
+}
+
+workb();
+```
+
+The `DEBUG` environment variable is then used to enable these based on space or
+comma-delimited names.
+
+Here are some examples:
+
+<img width="647" alt="screen shot 2017-08-08 at 12 53 04 pm" src="https://user-images.githubusercontent.com/71256/29091703-a6302cdc-7c38-11e7-8304-7c0b3bc600cd.png">
+<img width="647" alt="screen shot 2017-08-08 at 12 53 38 pm" src="https://user-images.githubusercontent.com/71256/29091700-a62a6888-7c38-11e7-800b-db911291ca2b.png">
+<img width="647" alt="screen shot 2017-08-08 at 12 53 25 pm" src="https://user-images.githubusercontent.com/71256/29091701-a62ea114-7c38-11e7-826a-2692bedca740.png">
+
+#### Windows command prompt notes
+
+##### CMD
+
+On Windows the environment variable is set using the `set` command.
+
+```cmd
+set DEBUG=*,-not_this
+```
+
+Example:
+
+```cmd
+set DEBUG=* & node app.js
+```
+
+##### PowerShell (VS Code default)
+
+PowerShell uses different syntax to set environment variables.
+
+```cmd
+$env:DEBUG = "*,-not_this"
+```
+
+Example:
+
+```cmd
+$env:DEBUG='app';node app.js
+```
+
+Then, run the program to be debugged as usual.
+
+npm script example:
+```js
+  "windowsDebug": "@powershell -Command $env:DEBUG='*';node app.js",
+```
+
+## Namespace Colors
+
+Every debug instance has a color generated for it based on its namespace name.
+This helps when visually parsing the debug output to identify which debug instance
+a debug line belongs to.
+
+#### Node.js
+
+In Node.js, colors are enabled when stderr is a TTY. You also _should_ install
+the [`supports-color`](https://npmjs.org/supports-color) module alongside debug,
+otherwise debug will only use a small handful of basic colors.
+
+<img width="521" src="https://user-images.githubusercontent.com/71256/29092181-47f6a9e6-7c3a-11e7-9a14-1928d8a711cd.png">
+
+#### Web Browser
+
+Colors are also enabled on "Web Inspectors" that understand the `%c` formatting
+option. These are WebKit web inspectors, Firefox ([since version
+31](https://hacks.mozilla.org/2014/05/editable-box-model-multiple-selection-sublime-text-keys-much-more-firefox-developer-tools-episode-31/))
+and the Firebug plugin for Firefox (any version).
+
+<img width="524" src="https://user-images.githubusercontent.com/71256/29092033-b65f9f2e-7c39-11e7-8e32-f6f0d8e865c1.png">
+
+
+## Millisecond diff
+
+When actively developing an application it can be useful to see when the time spent between one `debug()` call and the next. Suppose for example you invoke `debug()` before requesting a resource, and after as well, the "+NNNms" will show you how much time was spent between calls.
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091486-fa38524c-7c37-11e7-895f-e7ec8e1039b6.png">
+
+When stdout is not a TTY, `Date#toISOString()` is used, making it more useful for logging the debug information as shown below:
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091956-6bd78372-7c39-11e7-8c55-c948396d6edd.png">
+
+
+## Conventions
+
+If you're using this in one or more of your libraries, you _should_ use the name of your library so that developers may toggle debugging as desired without guessing names. If you have more than one debuggers you _should_ prefix them with your library name and use ":" to separate features. For example "bodyParser" from Connect would then be "connect:bodyParser".  If you append a "*" to the end of your name, it will always be enabled regardless of the setting of the DEBUG environment variable.  You can then use it for normal output as well as debug output.
+
+## Wildcards
+
+The `*` character may be used as a wildcard. Suppose for example your library has
+debuggers named "connect:bodyParser", "connect:compress", "connect:session",
+instead of listing all three with
+`DEBUG=connect:bodyParser,connect:compress,connect:session`, you may simply do
+`DEBUG=connect:*`, or to run everything using this module simply use `DEBUG=*`.
+
+You can also exclude specific debuggers by prefixing them with a "-" character.
+For example, `DEBUG=*,-connect:*` would include all debuggers except those
+starting with "connect:".
+
+## Environment Variables
+
+When running through Node.js, you can set a few environment variables that will
+change the behavior of the debug logging:
+
+| Name      | Purpose                                         |
+|-----------|-------------------------------------------------|
+| `DEBUG`   | Enables/disables specific debugging namespaces. |
+| `DEBUG_HIDE_DATE` | Hide date from debug output (non-TTY).  |
+| `DEBUG_COLORS`| Whether or not to use colors in the debug output. |
+| `DEBUG_DEPTH` | Object inspection depth.                    |
+| `DEBUG_SHOW_HIDDEN` | Shows hidden properties on inspected objects. |
+
+
+__Note:__ The environment variables beginning with `DEBUG_` end up being
+converted into an Options object that gets used with `%o`/`%O` formatters.
+See the Node.js documentation for
+[`util.inspect()`](https://nodejs.org/api/util.html#util_util_inspect_object_options)
+for the complete list.
+
+## Formatters
+
+Debug uses [printf-style](https://wikipedia.org/wiki/Printf_format_string) formatting.
+Below are the officially supported formatters:
+
+| Formatter | Representation |
+|-----------|----------------|
+| `%O`      | Pretty-print an Object on multiple lines. |
+| `%o`      | Pretty-print an Object all on a single line. |
+| `%s`      | String. |
+| `%d`      | Number (both integer and float). |
+| `%j`      | JSON. Replaced with the string '[Circular]' if the argument contains circular references. |
+| `%%`      | Single percent sign ('%'). This does not consume an argument. |
+
+
+### Custom formatters
+
+You can add custom formatters by extending the `debug.formatters` object.
+For example, if you wanted to add support for rendering a Buffer as hex with
+`%h`, you could do something like:
+
+```js
+const createDebug = require('debug')
+createDebug.formatters.h = (v) => {
+  return v.toString('hex')
+}
+
+// …elsewhere
+const debug = createDebug('foo')
+debug('this is hex: %h', new Buffer('hello world'))
+//   foo this is hex: 68656c6c6f20776f726c6421 +0ms
+```
+
+
+## Browser Support
+
+You can build a browser-ready script using [browserify](https://github.com/substack/node-browserify),
+or just use the [browserify-as-a-service](https://wzrd.in/) [build](https://wzrd.in/standalone/debug@latest),
+if you don't want to build it yourself.
+
+Debug's enable state is currently persisted by `localStorage`.
+Consider the situation shown below where you have `worker:a` and `worker:b`,
+and wish to debug both. You can enable this using `localStorage.debug`:
+
+```js
+localStorage.debug = 'worker:*'
+```
+
+And then refresh the page.
+
+```js
+a = debug('worker:a');
+b = debug('worker:b');
+
+setInterval(function(){
+  a('doing some work');
+}, 1000);
+
+setInterval(function(){
+  b('doing some work');
+}, 1200);
+```
+
+In Chromium-based web browsers (e.g. Brave, Chrome, and Electron), the JavaScript console will—by default—only show messages logged by `debug` if the "Verbose" log level is _enabled_.
+
+<img width="647" src="https://user-images.githubusercontent.com/7143133/152083257-29034707-c42c-4959-8add-3cee850e6fcf.png">
+
+## Output streams
+
+  By default `debug` will log to stderr, however this can be configured per-namespace by overriding the `log` method:
+
+Example [_stdout.js_](./examples/node/stdout.js):
+
+```js
+var debug = require('debug');
+var error = debug('app:error');
+
+// by default stderr is used
+error('goes to stderr!');
+
+var log = debug('app:log');
+// set this namespace to log via console.log
+log.log = console.log.bind(console); // don't forget to bind to console!
+log('goes to stdout');
+error('still goes to stderr!');
+
+// set all output to go via console.info
+// overrides all per-namespace log settings
+debug.log = console.info.bind(console);
+error('now goes to stdout via console.info');
+log('still goes to stdout, but via console.info now');
+```
+
+## Extend
+You can simply extend debugger 
+```js
+const log = require('debug')('auth');
+
+//creates new debug instance with extended namespace
+const logSign = log.extend('sign');
+const logLogin = log.extend('login');
+
+log('hello'); // auth hello
+logSign('hello'); //auth:sign hello
+logLogin('hello'); //auth:login hello
+```
+
+## Set dynamically
+
+You can also enable debug dynamically by calling the `enable()` method :
+
+```js
+let debug = require('debug');
+
+console.log(1, debug.enabled('test'));
+
+debug.enable('test');
+console.log(2, debug.enabled('test'));
+
+debug.disable();
+console.log(3, debug.enabled('test'));
+
+```
+
+print :   
+```
+1 false
+2 true
+3 false
+```
+
+Usage :  
+`enable(namespaces)`  
+`namespaces` can include modes separated by a colon and wildcards.
+   
+Note that calling `enable()` completely overrides previously set DEBUG variable : 
+
+```
+$ DEBUG=foo node -e 'var dbg = require("debug"); dbg.enable("bar"); console.log(dbg.enabled("foo"))'
+=> false
+```
+
+`disable()`
+
+Will disable all namespaces. The functions returns the namespaces currently
+enabled (and skipped). This can be useful if you want to disable debugging
+temporarily without knowing what was enabled to begin with.
+
+For example:
+
+```js
+let debug = require('debug');
+debug.enable('foo:*,-foo:bar');
+let namespaces = debug.disable();
+debug.enable(namespaces);
+```
+
+Note: There is no guarantee that the string will be identical to the initial
+enable string, but semantically they will be identical.
+
+## Checking whether a debug target is enabled
+
+After you've created a debug instance, you can determine whether or not it is
+enabled by checking the `enabled` property:
+
+```javascript
+const debug = require('debug')('http');
+
+if (debug.enabled) {
+  // do stuff...
+}
+```
+
+You can also manually toggle this property to force the debug instance to be
+enabled or disabled.
+
+## Usage in child processes
+
+Due to the way `debug` detects if the output is a TTY or not, colors are not shown in child processes when `stderr` is piped. A solution is to pass the `DEBUG_COLORS=1` environment variable to the child process.  
+For example:
+
+```javascript
+worker = fork(WORKER_WRAP_PATH, [workerPath], {
+  stdio: [
+    /* stdin: */ 0,
+    /* stdout: */ 'pipe',
+    /* stderr: */ 'pipe',
+    'ipc',
+  ],
+  env: Object.assign({}, process.env, {
+    DEBUG_COLORS: 1 // without this settings, colors won't be shown
+  }),
+});
+
+worker.stderr.pipe(process.stderr, { end: false });
+```
+
+
+## Authors
+
+ - TJ Holowaychuk
+ - Nathan Rajlich
+ - Andrew Rhyne
+ - Josh Junon
+
+## Backers
+
+Support us with a monthly donation and help us continue our activities. [[Become a backer](https://opencollective.com/debug#backer)]
+
+<a href="https://opencollective.com/debug/backer/0/website" target="_blank"><img src="https://opencollective.com/debug/backer/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/1/website" target="_blank"><img src="https://opencollective.com/debug/backer/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/2/website" target="_blank"><img src="https://opencollective.com/debug/backer/2/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/3/website" target="_blank"><img src="https://opencollective.com/debug/backer/3/avatar.svg"></a>
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+<a href="https://opencollective.com/debug/backer/5/website" target="_blank"><img src="https://opencollective.com/debug/backer/5/avatar.svg"></a>
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+<a href="https://opencollective.com/debug/backer/24/website" target="_blank"><img src="https://opencollective.com/debug/backer/24/avatar.svg"></a>
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+<a href="https://opencollective.com/debug/backer/29/website" target="_blank"><img src="https://opencollective.com/debug/backer/29/avatar.svg"></a>
+
+
+## Sponsors
+
+Become a sponsor and get your logo on our README on Github with a link to your site. [[Become a sponsor](https://opencollective.com/debug#sponsor)]
+
+<a href="https://opencollective.com/debug/sponsor/0/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/1/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/2/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/2/avatar.svg"></a>
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+<a href="https://opencollective.com/debug/sponsor/17/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/17/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/18/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/18/avatar.svg"></a>
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+<a href="https://opencollective.com/debug/sponsor/21/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/21/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/22/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/22/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/23/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/23/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/24/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/24/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/25/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/25/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/26/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/26/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/27/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/27/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/28/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/28/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/29/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/29/avatar.svg"></a>
+
+## License
+
+(The MIT License)
+
+Copyright (c) 2014-2017 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2018-2021 Josh Junon
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/https-proxy-agent/node_modules/debug/package.json b/server/node_modules/https-proxy-agent/node_modules/debug/package.json
new file mode 100644
index 0000000..ee8abb5
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/debug/package.json
@@ -0,0 +1,64 @@
+{
+  "name": "debug",
+  "version": "4.4.3",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/debug-js/debug.git"
+  },
+  "description": "Lightweight debugging utility for Node.js and the browser",
+  "keywords": [
+    "debug",
+    "log",
+    "debugger"
+  ],
+  "files": [
+    "src",
+    "LICENSE",
+    "README.md"
+  ],
+  "author": "Josh Junon (https://github.com/qix-)",
+  "contributors": [
+    "TJ Holowaychuk <tj@vision-media.ca>",
+    "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io)",
+    "Andrew Rhyne <rhyneandrew@gmail.com>"
+  ],
+  "license": "MIT",
+  "scripts": {
+    "lint": "xo",
+    "test": "npm run test:node && npm run test:browser && npm run lint",
+    "test:node": "mocha test.js test.node.js",
+    "test:browser": "karma start --single-run",
+    "test:coverage": "cat ./coverage/lcov.info | coveralls"
+  },
+  "dependencies": {
+    "ms": "^2.1.3"
+  },
+  "devDependencies": {
+    "brfs": "^2.0.1",
+    "browserify": "^16.2.3",
+    "coveralls": "^3.0.2",
+    "karma": "^3.1.4",
+    "karma-browserify": "^6.0.0",
+    "karma-chrome-launcher": "^2.2.0",
+    "karma-mocha": "^1.3.0",
+    "mocha": "^5.2.0",
+    "mocha-lcov-reporter": "^1.2.0",
+    "sinon": "^14.0.0",
+    "xo": "^0.23.0"
+  },
+  "peerDependenciesMeta": {
+    "supports-color": {
+      "optional": true
+    }
+  },
+  "main": "./src/index.js",
+  "browser": "./src/browser.js",
+  "engines": {
+    "node": ">=6.0"
+  },
+  "xo": {
+    "rules": {
+      "import/extensions": "off"
+    }
+  }
+}
diff --git a/server/node_modules/https-proxy-agent/node_modules/debug/src/browser.js b/server/node_modules/https-proxy-agent/node_modules/debug/src/browser.js
new file mode 100644
index 0000000..5993451
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/debug/src/browser.js
@@ -0,0 +1,272 @@
+/* eslint-env browser */
+
+/**
+ * This is the web browser implementation of `debug()`.
+ */
+
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+exports.storage = localstorage();
+exports.destroy = (() => {
+	let warned = false;
+
+	return () => {
+		if (!warned) {
+			warned = true;
+			console.warn('Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.');
+		}
+	};
+})();
+
+/**
+ * Colors.
+ */
+
+exports.colors = [
+	'#0000CC',
+	'#0000FF',
+	'#0033CC',
+	'#0033FF',
+	'#0066CC',
+	'#0066FF',
+	'#0099CC',
+	'#0099FF',
+	'#00CC00',
+	'#00CC33',
+	'#00CC66',
+	'#00CC99',
+	'#00CCCC',
+	'#00CCFF',
+	'#3300CC',
+	'#3300FF',
+	'#3333CC',
+	'#3333FF',
+	'#3366CC',
+	'#3366FF',
+	'#3399CC',
+	'#3399FF',
+	'#33CC00',
+	'#33CC33',
+	'#33CC66',
+	'#33CC99',
+	'#33CCCC',
+	'#33CCFF',
+	'#6600CC',
+	'#6600FF',
+	'#6633CC',
+	'#6633FF',
+	'#66CC00',
+	'#66CC33',
+	'#9900CC',
+	'#9900FF',
+	'#9933CC',
+	'#9933FF',
+	'#99CC00',
+	'#99CC33',
+	'#CC0000',
+	'#CC0033',
+	'#CC0066',
+	'#CC0099',
+	'#CC00CC',
+	'#CC00FF',
+	'#CC3300',
+	'#CC3333',
+	'#CC3366',
+	'#CC3399',
+	'#CC33CC',
+	'#CC33FF',
+	'#CC6600',
+	'#CC6633',
+	'#CC9900',
+	'#CC9933',
+	'#CCCC00',
+	'#CCCC33',
+	'#FF0000',
+	'#FF0033',
+	'#FF0066',
+	'#FF0099',
+	'#FF00CC',
+	'#FF00FF',
+	'#FF3300',
+	'#FF3333',
+	'#FF3366',
+	'#FF3399',
+	'#FF33CC',
+	'#FF33FF',
+	'#FF6600',
+	'#FF6633',
+	'#FF9900',
+	'#FF9933',
+	'#FFCC00',
+	'#FFCC33'
+];
+
+/**
+ * Currently only WebKit-based Web Inspectors, Firefox >= v31,
+ * and the Firebug extension (any Firefox version) are known
+ * to support "%c" CSS customizations.
+ *
+ * TODO: add a `localStorage` variable to explicitly enable/disable colors
+ */
+
+// eslint-disable-next-line complexity
+function useColors() {
+	// NB: In an Electron preload script, document will be defined but not fully
+	// initialized. Since we know we're in Chrome, we'll just detect this case
+	// explicitly
+	if (typeof window !== 'undefined' && window.process && (window.process.type === 'renderer' || window.process.__nwjs)) {
+		return true;
+	}
+
+	// Internet Explorer and Edge do not support colors.
+	if (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/(edge|trident)\/(\d+)/)) {
+		return false;
+	}
+
+	let m;
+
+	// Is webkit? http://stackoverflow.com/a/16459606/376773
+	// document is undefined in react-native: https://github.com/facebook/react-native/pull/1632
+	// eslint-disable-next-line no-return-assign
+	return (typeof document !== 'undefined' && document.documentElement && document.documentElement.style && document.documentElement.style.WebkitAppearance) ||
+		// Is firebug? http://stackoverflow.com/a/398120/376773
+		(typeof window !== 'undefined' && window.console && (window.console.firebug || (window.console.exception && window.console.table))) ||
+		// Is firefox >= v31?
+		// https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
+		(typeof navigator !== 'undefined' && navigator.userAgent && (m = navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/)) && parseInt(m[1], 10) >= 31) ||
+		// Double check webkit in userAgent just in case we are in a worker
+		(typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/applewebkit\/(\d+)/));
+}
+
+/**
+ * Colorize log arguments if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+	args[0] = (this.useColors ? '%c' : '') +
+		this.namespace +
+		(this.useColors ? ' %c' : ' ') +
+		args[0] +
+		(this.useColors ? '%c ' : ' ') +
+		'+' + module.exports.humanize(this.diff);
+
+	if (!this.useColors) {
+		return;
+	}
+
+	const c = 'color: ' + this.color;
+	args.splice(1, 0, c, 'color: inherit');
+
+	// The final "%c" is somewhat tricky, because there could be other
+	// arguments passed either before or after the %c, so we need to
+	// figure out the correct index to insert the CSS into
+	let index = 0;
+	let lastC = 0;
+	args[0].replace(/%[a-zA-Z%]/g, match => {
+		if (match === '%%') {
+			return;
+		}
+		index++;
+		if (match === '%c') {
+			// We only are interested in the *last* %c
+			// (the user may have provided their own)
+			lastC = index;
+		}
+	});
+
+	args.splice(lastC, 0, c);
+}
+
+/**
+ * Invokes `console.debug()` when available.
+ * No-op when `console.debug` is not a "function".
+ * If `console.debug` is not available, falls back
+ * to `console.log`.
+ *
+ * @api public
+ */
+exports.log = console.debug || console.log || (() => {});
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+function save(namespaces) {
+	try {
+		if (namespaces) {
+			exports.storage.setItem('debug', namespaces);
+		} else {
+			exports.storage.removeItem('debug');
+		}
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+function load() {
+	let r;
+	try {
+		r = exports.storage.getItem('debug') || exports.storage.getItem('DEBUG') ;
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+
+	// If debug isn't set in LS, and we're in Electron, try to load $DEBUG
+	if (!r && typeof process !== 'undefined' && 'env' in process) {
+		r = process.env.DEBUG;
+	}
+
+	return r;
+}
+
+/**
+ * Localstorage attempts to return the localstorage.
+ *
+ * This is necessary because safari throws
+ * when a user disables cookies/localstorage
+ * and you attempt to access it.
+ *
+ * @return {LocalStorage}
+ * @api private
+ */
+
+function localstorage() {
+	try {
+		// TVMLKit (Apple TV JS Runtime) does not have a window object, just localStorage in the global context
+		// The Browser also has localStorage in the global context.
+		return localStorage;
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+}
+
+module.exports = require('./common')(exports);
+
+const {formatters} = module.exports;
+
+/**
+ * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
+ */
+
+formatters.j = function (v) {
+	try {
+		return JSON.stringify(v);
+	} catch (error) {
+		return '[UnexpectedJSONParseError]: ' + error.message;
+	}
+};
diff --git a/server/node_modules/https-proxy-agent/node_modules/debug/src/common.js b/server/node_modules/https-proxy-agent/node_modules/debug/src/common.js
new file mode 100644
index 0000000..141cb57
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/debug/src/common.js
@@ -0,0 +1,292 @@
+
+/**
+ * This is the common logic for both the Node.js and web browser
+ * implementations of `debug()`.
+ */
+
+function setup(env) {
+	createDebug.debug = createDebug;
+	createDebug.default = createDebug;
+	createDebug.coerce = coerce;
+	createDebug.disable = disable;
+	createDebug.enable = enable;
+	createDebug.enabled = enabled;
+	createDebug.humanize = require('ms');
+	createDebug.destroy = destroy;
+
+	Object.keys(env).forEach(key => {
+		createDebug[key] = env[key];
+	});
+
+	/**
+	* The currently active debug mode names, and names to skip.
+	*/
+
+	createDebug.names = [];
+	createDebug.skips = [];
+
+	/**
+	* Map of special "%n" handling functions, for the debug "format" argument.
+	*
+	* Valid key names are a single, lower or upper-case letter, i.e. "n" and "N".
+	*/
+	createDebug.formatters = {};
+
+	/**
+	* Selects a color for a debug namespace
+	* @param {String} namespace The namespace string for the debug instance to be colored
+	* @return {Number|String} An ANSI color code for the given namespace
+	* @api private
+	*/
+	function selectColor(namespace) {
+		let hash = 0;
+
+		for (let i = 0; i < namespace.length; i++) {
+			hash = ((hash << 5) - hash) + namespace.charCodeAt(i);
+			hash |= 0; // Convert to 32bit integer
+		}
+
+		return createDebug.colors[Math.abs(hash) % createDebug.colors.length];
+	}
+	createDebug.selectColor = selectColor;
+
+	/**
+	* Create a debugger with the given `namespace`.
+	*
+	* @param {String} namespace
+	* @return {Function}
+	* @api public
+	*/
+	function createDebug(namespace) {
+		let prevTime;
+		let enableOverride = null;
+		let namespacesCache;
+		let enabledCache;
+
+		function debug(...args) {
+			// Disabled?
+			if (!debug.enabled) {
+				return;
+			}
+
+			const self = debug;
+
+			// Set `diff` timestamp
+			const curr = Number(new Date());
+			const ms = curr - (prevTime || curr);
+			self.diff = ms;
+			self.prev = prevTime;
+			self.curr = curr;
+			prevTime = curr;
+
+			args[0] = createDebug.coerce(args[0]);
+
+			if (typeof args[0] !== 'string') {
+				// Anything else let's inspect with %O
+				args.unshift('%O');
+			}
+
+			// Apply any `formatters` transformations
+			let index = 0;
+			args[0] = args[0].replace(/%([a-zA-Z%])/g, (match, format) => {
+				// If we encounter an escaped % then don't increase the array index
+				if (match === '%%') {
+					return '%';
+				}
+				index++;
+				const formatter = createDebug.formatters[format];
+				if (typeof formatter === 'function') {
+					const val = args[index];
+					match = formatter.call(self, val);
+
+					// Now we need to remove `args[index]` since it's inlined in the `format`
+					args.splice(index, 1);
+					index--;
+				}
+				return match;
+			});
+
+			// Apply env-specific formatting (colors, etc.)
+			createDebug.formatArgs.call(self, args);
+
+			const logFn = self.log || createDebug.log;
+			logFn.apply(self, args);
+		}
+
+		debug.namespace = namespace;
+		debug.useColors = createDebug.useColors();
+		debug.color = createDebug.selectColor(namespace);
+		debug.extend = extend;
+		debug.destroy = createDebug.destroy; // XXX Temporary. Will be removed in the next major release.
+
+		Object.defineProperty(debug, 'enabled', {
+			enumerable: true,
+			configurable: false,
+			get: () => {
+				if (enableOverride !== null) {
+					return enableOverride;
+				}
+				if (namespacesCache !== createDebug.namespaces) {
+					namespacesCache = createDebug.namespaces;
+					enabledCache = createDebug.enabled(namespace);
+				}
+
+				return enabledCache;
+			},
+			set: v => {
+				enableOverride = v;
+			}
+		});
+
+		// Env-specific initialization logic for debug instances
+		if (typeof createDebug.init === 'function') {
+			createDebug.init(debug);
+		}
+
+		return debug;
+	}
+
+	function extend(namespace, delimiter) {
+		const newDebug = createDebug(this.namespace + (typeof delimiter === 'undefined' ? ':' : delimiter) + namespace);
+		newDebug.log = this.log;
+		return newDebug;
+	}
+
+	/**
+	* Enables a debug mode by namespaces. This can include modes
+	* separated by a colon and wildcards.
+	*
+	* @param {String} namespaces
+	* @api public
+	*/
+	function enable(namespaces) {
+		createDebug.save(namespaces);
+		createDebug.namespaces = namespaces;
+
+		createDebug.names = [];
+		createDebug.skips = [];
+
+		const split = (typeof namespaces === 'string' ? namespaces : '')
+			.trim()
+			.replace(/\s+/g, ',')
+			.split(',')
+			.filter(Boolean);
+
+		for (const ns of split) {
+			if (ns[0] === '-') {
+				createDebug.skips.push(ns.slice(1));
+			} else {
+				createDebug.names.push(ns);
+			}
+		}
+	}
+
+	/**
+	 * Checks if the given string matches a namespace template, honoring
+	 * asterisks as wildcards.
+	 *
+	 * @param {String} search
+	 * @param {String} template
+	 * @return {Boolean}
+	 */
+	function matchesTemplate(search, template) {
+		let searchIndex = 0;
+		let templateIndex = 0;
+		let starIndex = -1;
+		let matchIndex = 0;
+
+		while (searchIndex < search.length) {
+			if (templateIndex < template.length && (template[templateIndex] === search[searchIndex] || template[templateIndex] === '*')) {
+				// Match character or proceed with wildcard
+				if (template[templateIndex] === '*') {
+					starIndex = templateIndex;
+					matchIndex = searchIndex;
+					templateIndex++; // Skip the '*'
+				} else {
+					searchIndex++;
+					templateIndex++;
+				}
+			} else if (starIndex !== -1) { // eslint-disable-line no-negated-condition
+				// Backtrack to the last '*' and try to match more characters
+				templateIndex = starIndex + 1;
+				matchIndex++;
+				searchIndex = matchIndex;
+			} else {
+				return false; // No match
+			}
+		}
+
+		// Handle trailing '*' in template
+		while (templateIndex < template.length && template[templateIndex] === '*') {
+			templateIndex++;
+		}
+
+		return templateIndex === template.length;
+	}
+
+	/**
+	* Disable debug output.
+	*
+	* @return {String} namespaces
+	* @api public
+	*/
+	function disable() {
+		const namespaces = [
+			...createDebug.names,
+			...createDebug.skips.map(namespace => '-' + namespace)
+		].join(',');
+		createDebug.enable('');
+		return namespaces;
+	}
+
+	/**
+	* Returns true if the given mode name is enabled, false otherwise.
+	*
+	* @param {String} name
+	* @return {Boolean}
+	* @api public
+	*/
+	function enabled(name) {
+		for (const skip of createDebug.skips) {
+			if (matchesTemplate(name, skip)) {
+				return false;
+			}
+		}
+
+		for (const ns of createDebug.names) {
+			if (matchesTemplate(name, ns)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	* Coerce `val`.
+	*
+	* @param {Mixed} val
+	* @return {Mixed}
+	* @api private
+	*/
+	function coerce(val) {
+		if (val instanceof Error) {
+			return val.stack || val.message;
+		}
+		return val;
+	}
+
+	/**
+	* XXX DO NOT USE. This is a temporary stub function.
+	* XXX It WILL be removed in the next major release.
+	*/
+	function destroy() {
+		console.warn('Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.');
+	}
+
+	createDebug.enable(createDebug.load());
+
+	return createDebug;
+}
+
+module.exports = setup;
diff --git a/server/node_modules/https-proxy-agent/node_modules/debug/src/index.js b/server/node_modules/https-proxy-agent/node_modules/debug/src/index.js
new file mode 100644
index 0000000..bf4c57f
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/debug/src/index.js
@@ -0,0 +1,10 @@
+/**
+ * Detect Electron renderer / nwjs process, which is node, but we should
+ * treat as a browser.
+ */
+
+if (typeof process === 'undefined' || process.type === 'renderer' || process.browser === true || process.__nwjs) {
+	module.exports = require('./browser.js');
+} else {
+	module.exports = require('./node.js');
+}
diff --git a/server/node_modules/https-proxy-agent/node_modules/debug/src/node.js b/server/node_modules/https-proxy-agent/node_modules/debug/src/node.js
new file mode 100644
index 0000000..715560a
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/debug/src/node.js
@@ -0,0 +1,263 @@
+/**
+ * Module dependencies.
+ */
+
+const tty = require('tty');
+const util = require('util');
+
+/**
+ * This is the Node.js implementation of `debug()`.
+ */
+
+exports.init = init;
+exports.log = log;
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+exports.destroy = util.deprecate(
+	() => {},
+	'Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.'
+);
+
+/**
+ * Colors.
+ */
+
+exports.colors = [6, 2, 3, 4, 5, 1];
+
+try {
+	// Optional dependency (as in, doesn't need to be installed, NOT like optionalDependencies in package.json)
+	// eslint-disable-next-line import/no-extraneous-dependencies
+	const supportsColor = require('supports-color');
+
+	if (supportsColor && (supportsColor.stderr || supportsColor).level >= 2) {
+		exports.colors = [
+			20,
+			21,
+			26,
+			27,
+			32,
+			33,
+			38,
+			39,
+			40,
+			41,
+			42,
+			43,
+			44,
+			45,
+			56,
+			57,
+			62,
+			63,
+			68,
+			69,
+			74,
+			75,
+			76,
+			77,
+			78,
+			79,
+			80,
+			81,
+			92,
+			93,
+			98,
+			99,
+			112,
+			113,
+			128,
+			129,
+			134,
+			135,
+			148,
+			149,
+			160,
+			161,
+			162,
+			163,
+			164,
+			165,
+			166,
+			167,
+			168,
+			169,
+			170,
+			171,
+			172,
+			173,
+			178,
+			179,
+			184,
+			185,
+			196,
+			197,
+			198,
+			199,
+			200,
+			201,
+			202,
+			203,
+			204,
+			205,
+			206,
+			207,
+			208,
+			209,
+			214,
+			215,
+			220,
+			221
+		];
+	}
+} catch (error) {
+	// Swallow - we only care if `supports-color` is available; it doesn't have to be.
+}
+
+/**
+ * Build up the default `inspectOpts` object from the environment variables.
+ *
+ *   $ DEBUG_COLORS=no DEBUG_DEPTH=10 DEBUG_SHOW_HIDDEN=enabled node script.js
+ */
+
+exports.inspectOpts = Object.keys(process.env).filter(key => {
+	return /^debug_/i.test(key);
+}).reduce((obj, key) => {
+	// Camel-case
+	const prop = key
+		.substring(6)
+		.toLowerCase()
+		.replace(/_([a-z])/g, (_, k) => {
+			return k.toUpperCase();
+		});
+
+	// Coerce string value into JS value
+	let val = process.env[key];
+	if (/^(yes|on|true|enabled)$/i.test(val)) {
+		val = true;
+	} else if (/^(no|off|false|disabled)$/i.test(val)) {
+		val = false;
+	} else if (val === 'null') {
+		val = null;
+	} else {
+		val = Number(val);
+	}
+
+	obj[prop] = val;
+	return obj;
+}, {});
+
+/**
+ * Is stdout a TTY? Colored output is enabled when `true`.
+ */
+
+function useColors() {
+	return 'colors' in exports.inspectOpts ?
+		Boolean(exports.inspectOpts.colors) :
+		tty.isatty(process.stderr.fd);
+}
+
+/**
+ * Adds ANSI color escape codes if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+	const {namespace: name, useColors} = this;
+
+	if (useColors) {
+		const c = this.color;
+		const colorCode = '\u001B[3' + (c < 8 ? c : '8;5;' + c);
+		const prefix = `  ${colorCode};1m${name} \u001B[0m`;
+
+		args[0] = prefix + args[0].split('\n').join('\n' + prefix);
+		args.push(colorCode + 'm+' + module.exports.humanize(this.diff) + '\u001B[0m');
+	} else {
+		args[0] = getDate() + name + ' ' + args[0];
+	}
+}
+
+function getDate() {
+	if (exports.inspectOpts.hideDate) {
+		return '';
+	}
+	return new Date().toISOString() + ' ';
+}
+
+/**
+ * Invokes `util.formatWithOptions()` with the specified arguments and writes to stderr.
+ */
+
+function log(...args) {
+	return process.stderr.write(util.formatWithOptions(exports.inspectOpts, ...args) + '\n');
+}
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+function save(namespaces) {
+	if (namespaces) {
+		process.env.DEBUG = namespaces;
+	} else {
+		// If you set a process.env field to null or undefined, it gets cast to the
+		// string 'null' or 'undefined'. Just delete instead.
+		delete process.env.DEBUG;
+	}
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+
+function load() {
+	return process.env.DEBUG;
+}
+
+/**
+ * Init logic for `debug` instances.
+ *
+ * Create a new `inspectOpts` object in case `useColors` is set
+ * differently for a particular `debug` instance.
+ */
+
+function init(debug) {
+	debug.inspectOpts = {};
+
+	const keys = Object.keys(exports.inspectOpts);
+	for (let i = 0; i < keys.length; i++) {
+		debug.inspectOpts[keys[i]] = exports.inspectOpts[keys[i]];
+	}
+}
+
+module.exports = require('./common')(exports);
+
+const {formatters} = module.exports;
+
+/**
+ * Map %o to `util.inspect()`, all on a single line.
+ */
+
+formatters.o = function (v) {
+	this.inspectOpts.colors = this.useColors;
+	return util.inspect(v, this.inspectOpts)
+		.split('\n')
+		.map(str => str.trim())
+		.join(' ');
+};
+
+/**
+ * Map %O to `util.inspect()`, allowing multiple lines if needed.
+ */
+
+formatters.O = function (v) {
+	this.inspectOpts.colors = this.useColors;
+	return util.inspect(v, this.inspectOpts);
+};
diff --git a/server/node_modules/https-proxy-agent/node_modules/ms/index.js b/server/node_modules/https-proxy-agent/node_modules/ms/index.js
new file mode 100644
index 0000000..ea734fb
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/ms/index.js
@@ -0,0 +1,162 @@
+/**
+ * Helpers.
+ */
+
+var s = 1000;
+var m = s * 60;
+var h = m * 60;
+var d = h * 24;
+var w = d * 7;
+var y = d * 365.25;
+
+/**
+ * Parse or format the given `val`.
+ *
+ * Options:
+ *
+ *  - `long` verbose formatting [false]
+ *
+ * @param {String|Number} val
+ * @param {Object} [options]
+ * @throws {Error} throw an error if val is not a non-empty string or a number
+ * @return {String|Number}
+ * @api public
+ */
+
+module.exports = function (val, options) {
+  options = options || {};
+  var type = typeof val;
+  if (type === 'string' && val.length > 0) {
+    return parse(val);
+  } else if (type === 'number' && isFinite(val)) {
+    return options.long ? fmtLong(val) : fmtShort(val);
+  }
+  throw new Error(
+    'val is not a non-empty string or a valid number. val=' +
+      JSON.stringify(val)
+  );
+};
+
+/**
+ * Parse the given `str` and return milliseconds.
+ *
+ * @param {String} str
+ * @return {Number}
+ * @api private
+ */
+
+function parse(str) {
+  str = String(str);
+  if (str.length > 100) {
+    return;
+  }
+  var match = /^(-?(?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|weeks?|w|years?|yrs?|y)?$/i.exec(
+    str
+  );
+  if (!match) {
+    return;
+  }
+  var n = parseFloat(match[1]);
+  var type = (match[2] || 'ms').toLowerCase();
+  switch (type) {
+    case 'years':
+    case 'year':
+    case 'yrs':
+    case 'yr':
+    case 'y':
+      return n * y;
+    case 'weeks':
+    case 'week':
+    case 'w':
+      return n * w;
+    case 'days':
+    case 'day':
+    case 'd':
+      return n * d;
+    case 'hours':
+    case 'hour':
+    case 'hrs':
+    case 'hr':
+    case 'h':
+      return n * h;
+    case 'minutes':
+    case 'minute':
+    case 'mins':
+    case 'min':
+    case 'm':
+      return n * m;
+    case 'seconds':
+    case 'second':
+    case 'secs':
+    case 'sec':
+    case 's':
+      return n * s;
+    case 'milliseconds':
+    case 'millisecond':
+    case 'msecs':
+    case 'msec':
+    case 'ms':
+      return n;
+    default:
+      return undefined;
+  }
+}
+
+/**
+ * Short format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtShort(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return Math.round(ms / d) + 'd';
+  }
+  if (msAbs >= h) {
+    return Math.round(ms / h) + 'h';
+  }
+  if (msAbs >= m) {
+    return Math.round(ms / m) + 'm';
+  }
+  if (msAbs >= s) {
+    return Math.round(ms / s) + 's';
+  }
+  return ms + 'ms';
+}
+
+/**
+ * Long format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtLong(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return plural(ms, msAbs, d, 'day');
+  }
+  if (msAbs >= h) {
+    return plural(ms, msAbs, h, 'hour');
+  }
+  if (msAbs >= m) {
+    return plural(ms, msAbs, m, 'minute');
+  }
+  if (msAbs >= s) {
+    return plural(ms, msAbs, s, 'second');
+  }
+  return ms + ' ms';
+}
+
+/**
+ * Pluralization helper.
+ */
+
+function plural(ms, msAbs, n, name) {
+  var isPlural = msAbs >= n * 1.5;
+  return Math.round(ms / n) + ' ' + name + (isPlural ? 's' : '');
+}
diff --git a/server/node_modules/https-proxy-agent/node_modules/ms/license.md b/server/node_modules/https-proxy-agent/node_modules/ms/license.md
new file mode 100644
index 0000000..fa5d39b
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/ms/license.md
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2020 Vercel, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/https-proxy-agent/node_modules/ms/package.json b/server/node_modules/https-proxy-agent/node_modules/ms/package.json
new file mode 100644
index 0000000..4997189
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/ms/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "ms",
+  "version": "2.1.3",
+  "description": "Tiny millisecond conversion utility",
+  "repository": "vercel/ms",
+  "main": "./index",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "precommit": "lint-staged",
+    "lint": "eslint lib/* bin/*",
+    "test": "mocha tests.js"
+  },
+  "eslintConfig": {
+    "extends": "eslint:recommended",
+    "env": {
+      "node": true,
+      "es6": true
+    }
+  },
+  "lint-staged": {
+    "*.js": [
+      "npm run lint",
+      "prettier --single-quote --write",
+      "git add"
+    ]
+  },
+  "license": "MIT",
+  "devDependencies": {
+    "eslint": "4.18.2",
+    "expect.js": "0.3.1",
+    "husky": "0.14.3",
+    "lint-staged": "5.0.0",
+    "mocha": "4.0.1",
+    "prettier": "2.0.5"
+  }
+}
diff --git a/server/node_modules/https-proxy-agent/node_modules/ms/readme.md b/server/node_modules/https-proxy-agent/node_modules/ms/readme.md
new file mode 100644
index 0000000..0fc1abb
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/node_modules/ms/readme.md
@@ -0,0 +1,59 @@
+# ms
+
+![CI](https://github.com/vercel/ms/workflows/CI/badge.svg)
+
+Use this package to easily convert various time formats to milliseconds.
+
+## Examples
+
+```js
+ms('2 days')  // 172800000
+ms('1d')      // 86400000
+ms('10h')     // 36000000
+ms('2.5 hrs') // 9000000
+ms('2h')      // 7200000
+ms('1m')      // 60000
+ms('5s')      // 5000
+ms('1y')      // 31557600000
+ms('100')     // 100
+ms('-3 days') // -259200000
+ms('-1h')     // -3600000
+ms('-200')    // -200
+```
+
+### Convert from Milliseconds
+
+```js
+ms(60000)             // "1m"
+ms(2 * 60000)         // "2m"
+ms(-3 * 60000)        // "-3m"
+ms(ms('10 hours'))    // "10h"
+```
+
+### Time Format Written-Out
+
+```js
+ms(60000, { long: true })             // "1 minute"
+ms(2 * 60000, { long: true })         // "2 minutes"
+ms(-3 * 60000, { long: true })        // "-3 minutes"
+ms(ms('10 hours'), { long: true })    // "10 hours"
+```
+
+## Features
+
+- Works both in [Node.js](https://nodejs.org) and in the browser
+- If a number is supplied to `ms`, a string with a unit is returned
+- If a string that contains the number is supplied, it returns it as a number (e.g.: it returns `100` for `'100'`)
+- If you pass a string with a number and a valid unit, the number of equivalent milliseconds is returned
+
+## Related Packages
+
+- [ms.macro](https://github.com/knpwrs/ms.macro) - Run `ms` as a macro at build-time.
+
+## Caught a Bug?
+
+1. [Fork](https://help.github.com/articles/fork-a-repo/) this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device
+2. Link the package to the global module directory: `npm link`
+3. Within the module you want to test your local development instance of ms, just link it to the dependencies: `npm link ms`. Instead of the default one from npm, Node.js will now use your clone of ms!
+
+As always, you can run the tests using: `npm test`
diff --git a/server/node_modules/https-proxy-agent/package.json b/server/node_modules/https-proxy-agent/package.json
new file mode 100644
index 0000000..fb2aba1
--- /dev/null
+++ b/server/node_modules/https-proxy-agent/package.json
@@ -0,0 +1,56 @@
+{
+  "name": "https-proxy-agent",
+  "version": "5.0.1",
+  "description": "An HTTP(s) proxy `http.Agent` implementation for HTTPS",
+  "main": "dist/index",
+  "types": "dist/index",
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "prebuild": "rimraf dist",
+    "build": "tsc",
+    "test": "mocha --reporter spec",
+    "test-lint": "eslint src --ext .js,.ts",
+    "prepublishOnly": "npm run build"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/TooTallNate/node-https-proxy-agent.git"
+  },
+  "keywords": [
+    "https",
+    "proxy",
+    "endpoint",
+    "agent"
+  ],
+  "author": "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io/)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/TooTallNate/node-https-proxy-agent/issues"
+  },
+  "dependencies": {
+    "agent-base": "6",
+    "debug": "4"
+  },
+  "devDependencies": {
+    "@types/debug": "4",
+    "@types/node": "^12.12.11",
+    "@typescript-eslint/eslint-plugin": "1.6.0",
+    "@typescript-eslint/parser": "1.1.0",
+    "eslint": "5.16.0",
+    "eslint-config-airbnb": "17.1.0",
+    "eslint-config-prettier": "4.1.0",
+    "eslint-import-resolver-typescript": "1.1.1",
+    "eslint-plugin-import": "2.16.0",
+    "eslint-plugin-jsx-a11y": "6.2.1",
+    "eslint-plugin-react": "7.12.4",
+    "mocha": "^6.2.2",
+    "proxy": "1",
+    "rimraf": "^3.0.0",
+    "typescript": "^3.5.3"
+  },
+  "engines": {
+    "node": ">= 6"
+  }
+}
diff --git a/server/node_modules/humanize-ms/History.md b/server/node_modules/humanize-ms/History.md
new file mode 100644
index 0000000..b159587
--- /dev/null
+++ b/server/node_modules/humanize-ms/History.md
@@ -0,0 +1,25 @@
+
+1.2.1 / 2017-05-19
+==================
+
+  * fix: package.json to reduce vulnerabilities (#3)
+
+1.2.0 / 2016-05-21
+==================
+
+  * feat: warn with stack
+
+1.1.0 / 2016-04-04
+==================
+
+  * deps: upgrade ms to 0.7.0
+
+1.0.1 / 2014-12-31
+==================
+
+  * feat(index.js): warn when result is undefined
+
+1.0.0 / 2014-08-14
+==================
+
+  * init
diff --git a/server/node_modules/humanize-ms/LICENSE b/server/node_modules/humanize-ms/LICENSE
new file mode 100644
index 0000000..89de354
--- /dev/null
+++ b/server/node_modules/humanize-ms/LICENSE
@@ -0,0 +1,17 @@
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/humanize-ms/README.md b/server/node_modules/humanize-ms/README.md
new file mode 100644
index 0000000..20a2ca3
--- /dev/null
+++ b/server/node_modules/humanize-ms/README.md
@@ -0,0 +1,40 @@
+humanize-ms
+---------------
+
+[![NPM version][npm-image]][npm-url]
+[![build status][travis-image]][travis-url]
+[![Test coverage][coveralls-image]][coveralls-url]
+[![Gittip][gittip-image]][gittip-url]
+[![David deps][david-image]][david-url]
+
+[npm-image]: https://img.shields.io/npm/v/humanize-ms.svg?style=flat
+[npm-url]: https://npmjs.org/package/humanize-ms
+[travis-image]: https://img.shields.io/travis/node-modules/humanize-ms.svg?style=flat
+[travis-url]: https://travis-ci.org/node-modules/humanize-ms
+[coveralls-image]: https://img.shields.io/coveralls/node-modules/humanize-ms.svg?style=flat
+[coveralls-url]: https://coveralls.io/r/node-modules/humanize-ms?branch=master
+[gittip-image]: https://img.shields.io/gittip/dead-horse.svg?style=flat
+[gittip-url]: https://www.gittip.com/dead-horse/
+[david-image]: https://img.shields.io/david/node-modules/humanize-ms.svg?style=flat
+[david-url]: https://david-dm.org/node-modules/humanize-ms
+
+transform humanize time to ms
+
+## Installation
+
+```bash
+$ npm install humanize-ms
+```
+
+## Examples
+
+```js
+var ms = require('humanize-ms');
+
+ms('1s') // 1000
+ms(1000) // 1000
+```
+
+### License
+
+MIT
diff --git a/server/node_modules/humanize-ms/index.js b/server/node_modules/humanize-ms/index.js
new file mode 100644
index 0000000..660df81
--- /dev/null
+++ b/server/node_modules/humanize-ms/index.js
@@ -0,0 +1,24 @@
+/*!
+ * humanize-ms - index.js
+ * Copyright(c) 2014 dead_horse <dead_horse@qq.com>
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ */
+
+var util = require('util');
+var ms = require('ms');
+
+module.exports = function (t) {
+  if (typeof t === 'number') return t;
+  var r = ms(t);
+  if (r === undefined) {
+    var err = new Error(util.format('humanize-ms(%j) result undefined', t));
+    console.warn(err.stack);
+  }
+  return r;
+};
diff --git a/server/node_modules/humanize-ms/package.json b/server/node_modules/humanize-ms/package.json
new file mode 100644
index 0000000..da4ab7f
--- /dev/null
+++ b/server/node_modules/humanize-ms/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "humanize-ms",
+  "version": "1.2.1",
+  "description": "transform humanize time to ms",
+  "main": "index.js",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "test": "make test"
+  },
+  "keywords": [
+    "humanize",
+    "ms"
+  ],
+  "author": {
+    "name": "dead-horse",
+    "email": "dead_horse@qq.com",
+    "url": "http://deadhorse.me"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/node-modules/humanize-ms"
+  },
+  "license": "MIT",
+  "dependencies": {
+    "ms": "^2.0.0"
+  },
+  "devDependencies": {
+    "autod": "*",
+    "beautify-benchmark": "~0.2.4",
+    "benchmark": "~1.0.0",
+    "istanbul": "*",
+    "mocha": "*",
+    "should": "*"
+  }
+}
diff --git a/server/node_modules/iconv-lite/Changelog.md b/server/node_modules/iconv-lite/Changelog.md
new file mode 100644
index 0000000..f252313
--- /dev/null
+++ b/server/node_modules/iconv-lite/Changelog.md
@@ -0,0 +1,162 @@
+# 0.4.24 / 2018-08-22
+
+  * Added MIK encoding (#196, by @Ivan-Kalatchev)
+
+
+# 0.4.23 / 2018-05-07
+
+  * Fix deprecation warning in Node v10 due to the last usage of `new Buffer` (#185, by @felixbuenemann)
+  * Switched from NodeBuffer to Buffer in typings (#155 by @felixfbecker, #186 by @larssn)
+
+
+# 0.4.22 / 2018-05-05
+
+  * Use older semver style for dependencies to be compatible with Node version 0.10 (#182, by @dougwilson)
+  * Fix tests to accomodate fixes in Node v10 (#182, by @dougwilson)
+
+
+# 0.4.21 / 2018-04-06
+
+  * Fix encoding canonicalization (#156)
+  * Fix the paths in the "browser" field in package.json (#174 by @LMLB)
+  * Removed "contributors" section in package.json - see Git history instead.
+
+
+# 0.4.20 / 2018-04-06
+
+  * Updated `new Buffer()` usages with recommended replacements as it's being deprecated in Node v10 (#176, #178 by @ChALkeR)
+
+
+# 0.4.19 / 2017-09-09
+
+  * Fixed iso8859-1 codec regression in handling untranslatable characters (#162, caused by #147)
+  * Re-generated windows1255 codec, because it was updated in iconv project
+  * Fixed grammar in error message when iconv-lite is loaded with encoding other than utf8
+
+
+# 0.4.18 / 2017-06-13
+
+  * Fixed CESU-8 regression in Node v8.
+
+
+# 0.4.17 / 2017-04-22
+
+ * Updated typescript definition file to support Angular 2 AoT mode (#153 by @larssn)
+
+
+# 0.4.16 / 2017-04-22
+
+ * Added support for React Native (#150)
+ * Changed iso8859-1 encoding to usine internal 'binary' encoding, as it's the same thing (#147 by @mscdex)
+ * Fixed typo in Readme (#138 by @jiangzhuo)
+ * Fixed build for Node v6.10+ by making correct version comparison
+ * Added a warning if iconv-lite is loaded not as utf-8 (see #142)
+
+
+# 0.4.15 / 2016-11-21
+
+ * Fixed typescript type definition (#137)
+
+
+# 0.4.14 / 2016-11-20
+
+ * Preparation for v1.0
+ * Added Node v6 and latest Node versions to Travis CI test rig
+ * Deprecated Node v0.8 support
+ * Typescript typings (@larssn)
+ * Fix encoding of Euro character in GB 18030 (inspired by @lygstate)
+ * Add ms prefix to dbcs windows encodings (@rokoroku)
+
+
+# 0.4.13 / 2015-10-01
+
+ * Fix silly mistake in deprecation notice.
+
+
+# 0.4.12 / 2015-09-26
+
+ * Node v4 support:
+   * Added CESU-8 decoding (#106)
+   * Added deprecation notice for `extendNodeEncodings`
+   * Added Travis tests for Node v4 and io.js latest (#105 by @Mithgol)
+
+
+# 0.4.11 / 2015-07-03
+
+ * Added CESU-8 encoding.
+
+
+# 0.4.10 / 2015-05-26
+
+ * Changed UTF-16 endianness heuristic to take into account any ASCII chars, not
+   just spaces. This should minimize the importance of "default" endianness.
+
+
+# 0.4.9 / 2015-05-24
+
+ * Streamlined BOM handling: strip BOM by default, add BOM when encoding if 
+   addBOM: true. Added docs to Readme.
+ * UTF16 now uses UTF16-LE by default.
+ * Fixed minor issue with big5 encoding.
+ * Added io.js testing on Travis; updated node-iconv version to test against.
+   Now we just skip testing SBCS encodings that node-iconv doesn't support.
+ * (internal refactoring) Updated codec interface to use classes.
+ * Use strict mode in all files.
+
+
+# 0.4.8 / 2015-04-14
+ 
+ * added alias UNICODE-1-1-UTF-7 for UTF-7 encoding (#94)
+
+
+# 0.4.7 / 2015-02-05
+
+ * stop official support of Node.js v0.8. Should still work, but no guarantees.
+   reason: Packages needed for testing are hard to get on Travis CI.
+ * work in environment where Object.prototype is monkey patched with enumerable 
+   props (#89).
+
+
+# 0.4.6 / 2015-01-12
+ 
+ * fix rare aliases of single-byte encodings (thanks @mscdex)
+ * double the timeout for dbcs tests to make them less flaky on travis
+
+
+# 0.4.5 / 2014-11-20
+
+ * fix windows-31j and x-sjis encoding support (@nleush)
+ * minor fix: undefined variable reference when internal error happens
+
+
+# 0.4.4 / 2014-07-16
+
+ * added encodings UTF-7 (RFC2152) and UTF-7-IMAP (RFC3501 Section 5.1.3)
+ * fixed streaming base64 encoding
+
+
+# 0.4.3 / 2014-06-14
+
+ * added encodings UTF-16BE and UTF-16 with BOM
+
+
+# 0.4.2 / 2014-06-12
+
+ * don't throw exception if `extendNodeEncodings()` is called more than once
+
+
+# 0.4.1 / 2014-06-11
+
+ * codepage 808 added
+
+
+# 0.4.0 / 2014-06-10
+
+ * code is rewritten from scratch
+ * all widespread encodings are supported
+ * streaming interface added
+ * browserify compatibility added
+ * (optional) extend core primitive encodings to make usage even simpler
+ * moved from vows to mocha as the testing framework
+
+
diff --git a/server/node_modules/iconv-lite/LICENSE b/server/node_modules/iconv-lite/LICENSE
new file mode 100644
index 0000000..d518d83
--- /dev/null
+++ b/server/node_modules/iconv-lite/LICENSE
@@ -0,0 +1,21 @@
+Copyright (c) 2011 Alexander Shtuchkin
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/iconv-lite/README.md b/server/node_modules/iconv-lite/README.md
new file mode 100644
index 0000000..c981c37
--- /dev/null
+++ b/server/node_modules/iconv-lite/README.md
@@ -0,0 +1,156 @@
+## Pure JS character encoding conversion [![Build Status](https://travis-ci.org/ashtuchkin/iconv-lite.svg?branch=master)](https://travis-ci.org/ashtuchkin/iconv-lite)
+
+ * Doesn't need native code compilation. Works on Windows and in sandboxed environments like [Cloud9](http://c9.io).
+ * Used in popular projects like [Express.js (body_parser)](https://github.com/expressjs/body-parser), 
+   [Grunt](http://gruntjs.com/), [Nodemailer](http://www.nodemailer.com/), [Yeoman](http://yeoman.io/) and others.
+ * Faster than [node-iconv](https://github.com/bnoordhuis/node-iconv) (see below for performance comparison).
+ * Intuitive encode/decode API
+ * Streaming support for Node v0.10+
+ * [Deprecated] Can extend Node.js primitives (buffers, streams) to support all iconv-lite encodings.
+ * In-browser usage via [Browserify](https://github.com/substack/node-browserify) (~180k gzip compressed with Buffer shim included).
+ * Typescript [type definition file](https://github.com/ashtuchkin/iconv-lite/blob/master/lib/index.d.ts) included.
+ * React Native is supported (need to explicitly `npm install` two more modules: `buffer` and `stream`).
+ * License: MIT.
+
+[![NPM Stats](https://nodei.co/npm/iconv-lite.png?downloads=true&downloadRank=true)](https://npmjs.org/packages/iconv-lite/)
+
+## Usage
+### Basic API
+```javascript
+var iconv = require('iconv-lite');
+
+// Convert from an encoded buffer to js string.
+str = iconv.decode(Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]), 'win1251');
+
+// Convert from js string to an encoded buffer.
+buf = iconv.encode("Sample input string", 'win1251');
+
+// Check if encoding is supported
+iconv.encodingExists("us-ascii")
+```
+
+### Streaming API (Node v0.10+)
+```javascript
+
+// Decode stream (from binary stream to js strings)
+http.createServer(function(req, res) {
+    var converterStream = iconv.decodeStream('win1251');
+    req.pipe(converterStream);
+
+    converterStream.on('data', function(str) {
+        console.log(str); // Do something with decoded strings, chunk-by-chunk.
+    });
+});
+
+// Convert encoding streaming example
+fs.createReadStream('file-in-win1251.txt')
+    .pipe(iconv.decodeStream('win1251'))
+    .pipe(iconv.encodeStream('ucs2'))
+    .pipe(fs.createWriteStream('file-in-ucs2.txt'));
+
+// Sugar: all encode/decode streams have .collect(cb) method to accumulate data.
+http.createServer(function(req, res) {
+    req.pipe(iconv.decodeStream('win1251')).collect(function(err, body) {
+        assert(typeof body == 'string');
+        console.log(body); // full request body string
+    });
+});
+```
+
+### [Deprecated] Extend Node.js own encodings
+> NOTE: This doesn't work on latest Node versions. See [details](https://github.com/ashtuchkin/iconv-lite/wiki/Node-v4-compatibility).
+
+```javascript
+// After this call all Node basic primitives will understand iconv-lite encodings.
+iconv.extendNodeEncodings();
+
+// Examples:
+buf = new Buffer(str, 'win1251');
+buf.write(str, 'gbk');
+str = buf.toString('latin1');
+assert(Buffer.isEncoding('iso-8859-15'));
+Buffer.byteLength(str, 'us-ascii');
+
+http.createServer(function(req, res) {
+    req.setEncoding('big5');
+    req.collect(function(err, body) {
+        console.log(body);
+    });
+});
+
+fs.createReadStream("file.txt", "shift_jis");
+
+// External modules are also supported (if they use Node primitives, which they probably do).
+request = require('request');
+request({
+    url: "http://github.com/", 
+    encoding: "cp932"
+});
+
+// To remove extensions
+iconv.undoExtendNodeEncodings();
+```
+
+## Supported encodings
+
+ *  All node.js native encodings: utf8, ucs2 / utf16-le, ascii, binary, base64, hex.
+ *  Additional unicode encodings: utf16, utf16-be, utf-7, utf-7-imap.
+ *  All widespread singlebyte encodings: Windows 125x family, ISO-8859 family, 
+    IBM/DOS codepages, Macintosh family, KOI8 family, all others supported by iconv library. 
+    Aliases like 'latin1', 'us-ascii' also supported.
+ *  All widespread multibyte encodings: CP932, CP936, CP949, CP950, GB2312, GBK, GB18030, Big5, Shift_JIS, EUC-JP.
+
+See [all supported encodings on wiki](https://github.com/ashtuchkin/iconv-lite/wiki/Supported-Encodings).
+
+Most singlebyte encodings are generated automatically from [node-iconv](https://github.com/bnoordhuis/node-iconv). Thank you Ben Noordhuis and libiconv authors!
+
+Multibyte encodings are generated from [Unicode.org mappings](http://www.unicode.org/Public/MAPPINGS/) and [WHATWG Encoding Standard mappings](http://encoding.spec.whatwg.org/). Thank you, respective authors!
+
+
+## Encoding/decoding speed
+
+Comparison with node-iconv module (1000x256kb, on MacBook Pro, Core i5/2.6 GHz, Node v0.12.0). 
+Note: your results may vary, so please always check on your hardware.
+
+    operation             iconv@2.1.4   iconv-lite@0.4.7
+    ----------------------------------------------------------
+    encode('win1251')     ~96 Mb/s      ~320 Mb/s
+    decode('win1251')     ~95 Mb/s      ~246 Mb/s
+
+## BOM handling
+
+ * Decoding: BOM is stripped by default, unless overridden by passing `stripBOM: false` in options
+   (f.ex. `iconv.decode(buf, enc, {stripBOM: false})`).
+   A callback might also be given as a `stripBOM` parameter - it'll be called if BOM character was actually found.
+ * If you want to detect UTF-8 BOM when decoding other encodings, use [node-autodetect-decoder-stream](https://github.com/danielgindi/node-autodetect-decoder-stream) module.
+ * Encoding: No BOM added, unless overridden by `addBOM: true` option.
+
+## UTF-16 Encodings
+
+This library supports UTF-16LE, UTF-16BE and UTF-16 encodings. First two are straightforward, but UTF-16 is trying to be
+smart about endianness in the following ways:
+ * Decoding: uses BOM and 'spaces heuristic' to determine input endianness. Default is UTF-16LE, but can be 
+   overridden with `defaultEncoding: 'utf-16be'` option. Strips BOM unless `stripBOM: false`.
+ * Encoding: uses UTF-16LE and writes BOM by default. Use `addBOM: false` to override.
+
+## Other notes
+
+When decoding, be sure to supply a Buffer to decode() method, otherwise [bad things usually happen](https://github.com/ashtuchkin/iconv-lite/wiki/Use-Buffers-when-decoding).  
+Untranslatable characters are set to � or ?. No transliteration is currently supported.  
+Node versions 0.10.31 and 0.11.13 are buggy, don't use them (see #65, #77).  
+
+## Testing
+
+```bash
+$ git clone git@github.com:ashtuchkin/iconv-lite.git
+$ cd iconv-lite
+$ npm install
+$ npm test
+    
+$ # To view performance:
+$ node test/performance.js
+
+$ # To view test coverage:
+$ npm run coverage
+$ open coverage/lcov-report/index.html
+```
diff --git a/server/node_modules/iconv-lite/encodings/dbcs-codec.js b/server/node_modules/iconv-lite/encodings/dbcs-codec.js
new file mode 100644
index 0000000..1fe3e16
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/dbcs-codec.js
@@ -0,0 +1,555 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// Multibyte codec. In this scheme, a character is represented by 1 or more bytes.
+// Our codec supports UTF-16 surrogates, extensions for GB18030 and unicode sequences.
+// To save memory and loading time, we read table files only when requested.
+
+exports._dbcs = DBCSCodec;
+
+var UNASSIGNED = -1,
+    GB18030_CODE = -2,
+    SEQ_START  = -10,
+    NODE_START = -1000,
+    UNASSIGNED_NODE = new Array(0x100),
+    DEF_CHAR = -1;
+
+for (var i = 0; i < 0x100; i++)
+    UNASSIGNED_NODE[i] = UNASSIGNED;
+
+
+// Class DBCSCodec reads and initializes mapping tables.
+function DBCSCodec(codecOptions, iconv) {
+    this.encodingName = codecOptions.encodingName;
+    if (!codecOptions)
+        throw new Error("DBCS codec is called without the data.")
+    if (!codecOptions.table)
+        throw new Error("Encoding '" + this.encodingName + "' has no data.");
+
+    // Load tables.
+    var mappingTable = codecOptions.table();
+
+
+    // Decode tables: MBCS -> Unicode.
+
+    // decodeTables is a trie, encoded as an array of arrays of integers. Internal arrays are trie nodes and all have len = 256.
+    // Trie root is decodeTables[0].
+    // Values: >=  0 -> unicode character code. can be > 0xFFFF
+    //         == UNASSIGNED -> unknown/unassigned sequence.
+    //         == GB18030_CODE -> this is the end of a GB18030 4-byte sequence.
+    //         <= NODE_START -> index of the next node in our trie to process next byte.
+    //         <= SEQ_START  -> index of the start of a character code sequence, in decodeTableSeq.
+    this.decodeTables = [];
+    this.decodeTables[0] = UNASSIGNED_NODE.slice(0); // Create root node.
+
+    // Sometimes a MBCS char corresponds to a sequence of unicode chars. We store them as arrays of integers here. 
+    this.decodeTableSeq = [];
+
+    // Actual mapping tables consist of chunks. Use them to fill up decode tables.
+    for (var i = 0; i < mappingTable.length; i++)
+        this._addDecodeChunk(mappingTable[i]);
+
+    this.defaultCharUnicode = iconv.defaultCharUnicode;
+
+    
+    // Encode tables: Unicode -> DBCS.
+
+    // `encodeTable` is array mapping from unicode char to encoded char. All its values are integers for performance.
+    // Because it can be sparse, it is represented as array of buckets by 256 chars each. Bucket can be null.
+    // Values: >=  0 -> it is a normal char. Write the value (if <=256 then 1 byte, if <=65536 then 2 bytes, etc.).
+    //         == UNASSIGNED -> no conversion found. Output a default char.
+    //         <= SEQ_START  -> it's an index in encodeTableSeq, see below. The character starts a sequence.
+    this.encodeTable = [];
+    
+    // `encodeTableSeq` is used when a sequence of unicode characters is encoded as a single code. We use a tree of
+    // objects where keys correspond to characters in sequence and leafs are the encoded dbcs values. A special DEF_CHAR key
+    // means end of sequence (needed when one sequence is a strict subsequence of another).
+    // Objects are kept separately from encodeTable to increase performance.
+    this.encodeTableSeq = [];
+
+    // Some chars can be decoded, but need not be encoded.
+    var skipEncodeChars = {};
+    if (codecOptions.encodeSkipVals)
+        for (var i = 0; i < codecOptions.encodeSkipVals.length; i++) {
+            var val = codecOptions.encodeSkipVals[i];
+            if (typeof val === 'number')
+                skipEncodeChars[val] = true;
+            else
+                for (var j = val.from; j <= val.to; j++)
+                    skipEncodeChars[j] = true;
+        }
+        
+    // Use decode trie to recursively fill out encode tables.
+    this._fillEncodeTable(0, 0, skipEncodeChars);
+
+    // Add more encoding pairs when needed.
+    if (codecOptions.encodeAdd) {
+        for (var uChar in codecOptions.encodeAdd)
+            if (Object.prototype.hasOwnProperty.call(codecOptions.encodeAdd, uChar))
+                this._setEncodeChar(uChar.charCodeAt(0), codecOptions.encodeAdd[uChar]);
+    }
+
+    this.defCharSB  = this.encodeTable[0][iconv.defaultCharSingleByte.charCodeAt(0)];
+    if (this.defCharSB === UNASSIGNED) this.defCharSB = this.encodeTable[0]['?'];
+    if (this.defCharSB === UNASSIGNED) this.defCharSB = "?".charCodeAt(0);
+
+
+    // Load & create GB18030 tables when needed.
+    if (typeof codecOptions.gb18030 === 'function') {
+        this.gb18030 = codecOptions.gb18030(); // Load GB18030 ranges.
+
+        // Add GB18030 decode tables.
+        var thirdByteNodeIdx = this.decodeTables.length;
+        var thirdByteNode = this.decodeTables[thirdByteNodeIdx] = UNASSIGNED_NODE.slice(0);
+
+        var fourthByteNodeIdx = this.decodeTables.length;
+        var fourthByteNode = this.decodeTables[fourthByteNodeIdx] = UNASSIGNED_NODE.slice(0);
+
+        for (var i = 0x81; i <= 0xFE; i++) {
+            var secondByteNodeIdx = NODE_START - this.decodeTables[0][i];
+            var secondByteNode = this.decodeTables[secondByteNodeIdx];
+            for (var j = 0x30; j <= 0x39; j++)
+                secondByteNode[j] = NODE_START - thirdByteNodeIdx;
+        }
+        for (var i = 0x81; i <= 0xFE; i++)
+            thirdByteNode[i] = NODE_START - fourthByteNodeIdx;
+        for (var i = 0x30; i <= 0x39; i++)
+            fourthByteNode[i] = GB18030_CODE
+    }        
+}
+
+DBCSCodec.prototype.encoder = DBCSEncoder;
+DBCSCodec.prototype.decoder = DBCSDecoder;
+
+// Decoder helpers
+DBCSCodec.prototype._getDecodeTrieNode = function(addr) {
+    var bytes = [];
+    for (; addr > 0; addr >>= 8)
+        bytes.push(addr & 0xFF);
+    if (bytes.length == 0)
+        bytes.push(0);
+
+    var node = this.decodeTables[0];
+    for (var i = bytes.length-1; i > 0; i--) { // Traverse nodes deeper into the trie.
+        var val = node[bytes[i]];
+
+        if (val == UNASSIGNED) { // Create new node.
+            node[bytes[i]] = NODE_START - this.decodeTables.length;
+            this.decodeTables.push(node = UNASSIGNED_NODE.slice(0));
+        }
+        else if (val <= NODE_START) { // Existing node.
+            node = this.decodeTables[NODE_START - val];
+        }
+        else
+            throw new Error("Overwrite byte in " + this.encodingName + ", addr: " + addr.toString(16));
+    }
+    return node;
+}
+
+
+DBCSCodec.prototype._addDecodeChunk = function(chunk) {
+    // First element of chunk is the hex mbcs code where we start.
+    var curAddr = parseInt(chunk[0], 16);
+
+    // Choose the decoding node where we'll write our chars.
+    var writeTable = this._getDecodeTrieNode(curAddr);
+    curAddr = curAddr & 0xFF;
+
+    // Write all other elements of the chunk to the table.
+    for (var k = 1; k < chunk.length; k++) {
+        var part = chunk[k];
+        if (typeof part === "string") { // String, write as-is.
+            for (var l = 0; l < part.length;) {
+                var code = part.charCodeAt(l++);
+                if (0xD800 <= code && code < 0xDC00) { // Decode surrogate
+                    var codeTrail = part.charCodeAt(l++);
+                    if (0xDC00 <= codeTrail && codeTrail < 0xE000)
+                        writeTable[curAddr++] = 0x10000 + (code - 0xD800) * 0x400 + (codeTrail - 0xDC00);
+                    else
+                        throw new Error("Incorrect surrogate pair in "  + this.encodingName + " at chunk " + chunk[0]);
+                }
+                else if (0x0FF0 < code && code <= 0x0FFF) { // Character sequence (our own encoding used)
+                    var len = 0xFFF - code + 2;
+                    var seq = [];
+                    for (var m = 0; m < len; m++)
+                        seq.push(part.charCodeAt(l++)); // Simple variation: don't support surrogates or subsequences in seq.
+
+                    writeTable[curAddr++] = SEQ_START - this.decodeTableSeq.length;
+                    this.decodeTableSeq.push(seq);
+                }
+                else
+                    writeTable[curAddr++] = code; // Basic char
+            }
+        } 
+        else if (typeof part === "number") { // Integer, meaning increasing sequence starting with prev character.
+            var charCode = writeTable[curAddr - 1] + 1;
+            for (var l = 0; l < part; l++)
+                writeTable[curAddr++] = charCode++;
+        }
+        else
+            throw new Error("Incorrect type '" + typeof part + "' given in "  + this.encodingName + " at chunk " + chunk[0]);
+    }
+    if (curAddr > 0xFF)
+        throw new Error("Incorrect chunk in "  + this.encodingName + " at addr " + chunk[0] + ": too long" + curAddr);
+}
+
+// Encoder helpers
+DBCSCodec.prototype._getEncodeBucket = function(uCode) {
+    var high = uCode >> 8; // This could be > 0xFF because of astral characters.
+    if (this.encodeTable[high] === undefined)
+        this.encodeTable[high] = UNASSIGNED_NODE.slice(0); // Create bucket on demand.
+    return this.encodeTable[high];
+}
+
+DBCSCodec.prototype._setEncodeChar = function(uCode, dbcsCode) {
+    var bucket = this._getEncodeBucket(uCode);
+    var low = uCode & 0xFF;
+    if (bucket[low] <= SEQ_START)
+        this.encodeTableSeq[SEQ_START-bucket[low]][DEF_CHAR] = dbcsCode; // There's already a sequence, set a single-char subsequence of it.
+    else if (bucket[low] == UNASSIGNED)
+        bucket[low] = dbcsCode;
+}
+
+DBCSCodec.prototype._setEncodeSequence = function(seq, dbcsCode) {
+    
+    // Get the root of character tree according to first character of the sequence.
+    var uCode = seq[0];
+    var bucket = this._getEncodeBucket(uCode);
+    var low = uCode & 0xFF;
+
+    var node;
+    if (bucket[low] <= SEQ_START) {
+        // There's already a sequence with  - use it.
+        node = this.encodeTableSeq[SEQ_START-bucket[low]];
+    }
+    else {
+        // There was no sequence object - allocate a new one.
+        node = {};
+        if (bucket[low] !== UNASSIGNED) node[DEF_CHAR] = bucket[low]; // If a char was set before - make it a single-char subsequence.
+        bucket[low] = SEQ_START - this.encodeTableSeq.length;
+        this.encodeTableSeq.push(node);
+    }
+
+    // Traverse the character tree, allocating new nodes as needed.
+    for (var j = 1; j < seq.length-1; j++) {
+        var oldVal = node[uCode];
+        if (typeof oldVal === 'object')
+            node = oldVal;
+        else {
+            node = node[uCode] = {}
+            if (oldVal !== undefined)
+                node[DEF_CHAR] = oldVal
+        }
+    }
+
+    // Set the leaf to given dbcsCode.
+    uCode = seq[seq.length-1];
+    node[uCode] = dbcsCode;
+}
+
+DBCSCodec.prototype._fillEncodeTable = function(nodeIdx, prefix, skipEncodeChars) {
+    var node = this.decodeTables[nodeIdx];
+    for (var i = 0; i < 0x100; i++) {
+        var uCode = node[i];
+        var mbCode = prefix + i;
+        if (skipEncodeChars[mbCode])
+            continue;
+
+        if (uCode >= 0)
+            this._setEncodeChar(uCode, mbCode);
+        else if (uCode <= NODE_START)
+            this._fillEncodeTable(NODE_START - uCode, mbCode << 8, skipEncodeChars);
+        else if (uCode <= SEQ_START)
+            this._setEncodeSequence(this.decodeTableSeq[SEQ_START - uCode], mbCode);
+    }
+}
+
+
+
+// == Encoder ==================================================================
+
+function DBCSEncoder(options, codec) {
+    // Encoder state
+    this.leadSurrogate = -1;
+    this.seqObj = undefined;
+    
+    // Static data
+    this.encodeTable = codec.encodeTable;
+    this.encodeTableSeq = codec.encodeTableSeq;
+    this.defaultCharSingleByte = codec.defCharSB;
+    this.gb18030 = codec.gb18030;
+}
+
+DBCSEncoder.prototype.write = function(str) {
+    var newBuf = Buffer.alloc(str.length * (this.gb18030 ? 4 : 3)),
+        leadSurrogate = this.leadSurrogate,
+        seqObj = this.seqObj, nextChar = -1,
+        i = 0, j = 0;
+
+    while (true) {
+        // 0. Get next character.
+        if (nextChar === -1) {
+            if (i == str.length) break;
+            var uCode = str.charCodeAt(i++);
+        }
+        else {
+            var uCode = nextChar;
+            nextChar = -1;    
+        }
+
+        // 1. Handle surrogates.
+        if (0xD800 <= uCode && uCode < 0xE000) { // Char is one of surrogates.
+            if (uCode < 0xDC00) { // We've got lead surrogate.
+                if (leadSurrogate === -1) {
+                    leadSurrogate = uCode;
+                    continue;
+                } else {
+                    leadSurrogate = uCode;
+                    // Double lead surrogate found.
+                    uCode = UNASSIGNED;
+                }
+            } else { // We've got trail surrogate.
+                if (leadSurrogate !== -1) {
+                    uCode = 0x10000 + (leadSurrogate - 0xD800) * 0x400 + (uCode - 0xDC00);
+                    leadSurrogate = -1;
+                } else {
+                    // Incomplete surrogate pair - only trail surrogate found.
+                    uCode = UNASSIGNED;
+                }
+                
+            }
+        }
+        else if (leadSurrogate !== -1) {
+            // Incomplete surrogate pair - only lead surrogate found.
+            nextChar = uCode; uCode = UNASSIGNED; // Write an error, then current char.
+            leadSurrogate = -1;
+        }
+
+        // 2. Convert uCode character.
+        var dbcsCode = UNASSIGNED;
+        if (seqObj !== undefined && uCode != UNASSIGNED) { // We are in the middle of the sequence
+            var resCode = seqObj[uCode];
+            if (typeof resCode === 'object') { // Sequence continues.
+                seqObj = resCode;
+                continue;
+
+            } else if (typeof resCode == 'number') { // Sequence finished. Write it.
+                dbcsCode = resCode;
+
+            } else if (resCode == undefined) { // Current character is not part of the sequence.
+
+                // Try default character for this sequence
+                resCode = seqObj[DEF_CHAR];
+                if (resCode !== undefined) {
+                    dbcsCode = resCode; // Found. Write it.
+                    nextChar = uCode; // Current character will be written too in the next iteration.
+
+                } else {
+                    // TODO: What if we have no default? (resCode == undefined)
+                    // Then, we should write first char of the sequence as-is and try the rest recursively.
+                    // Didn't do it for now because no encoding has this situation yet.
+                    // Currently, just skip the sequence and write current char.
+                }
+            }
+            seqObj = undefined;
+        }
+        else if (uCode >= 0) {  // Regular character
+            var subtable = this.encodeTable[uCode >> 8];
+            if (subtable !== undefined)
+                dbcsCode = subtable[uCode & 0xFF];
+            
+            if (dbcsCode <= SEQ_START) { // Sequence start
+                seqObj = this.encodeTableSeq[SEQ_START-dbcsCode];
+                continue;
+            }
+
+            if (dbcsCode == UNASSIGNED && this.gb18030) {
+                // Use GB18030 algorithm to find character(s) to write.
+                var idx = findIdx(this.gb18030.uChars, uCode);
+                if (idx != -1) {
+                    var dbcsCode = this.gb18030.gbChars[idx] + (uCode - this.gb18030.uChars[idx]);
+                    newBuf[j++] = 0x81 + Math.floor(dbcsCode / 12600); dbcsCode = dbcsCode % 12600;
+                    newBuf[j++] = 0x30 + Math.floor(dbcsCode / 1260); dbcsCode = dbcsCode % 1260;
+                    newBuf[j++] = 0x81 + Math.floor(dbcsCode / 10); dbcsCode = dbcsCode % 10;
+                    newBuf[j++] = 0x30 + dbcsCode;
+                    continue;
+                }
+            }
+        }
+
+        // 3. Write dbcsCode character.
+        if (dbcsCode === UNASSIGNED)
+            dbcsCode = this.defaultCharSingleByte;
+        
+        if (dbcsCode < 0x100) {
+            newBuf[j++] = dbcsCode;
+        }
+        else if (dbcsCode < 0x10000) {
+            newBuf[j++] = dbcsCode >> 8;   // high byte
+            newBuf[j++] = dbcsCode & 0xFF; // low byte
+        }
+        else {
+            newBuf[j++] = dbcsCode >> 16;
+            newBuf[j++] = (dbcsCode >> 8) & 0xFF;
+            newBuf[j++] = dbcsCode & 0xFF;
+        }
+    }
+
+    this.seqObj = seqObj;
+    this.leadSurrogate = leadSurrogate;
+    return newBuf.slice(0, j);
+}
+
+DBCSEncoder.prototype.end = function() {
+    if (this.leadSurrogate === -1 && this.seqObj === undefined)
+        return; // All clean. Most often case.
+
+    var newBuf = Buffer.alloc(10), j = 0;
+
+    if (this.seqObj) { // We're in the sequence.
+        var dbcsCode = this.seqObj[DEF_CHAR];
+        if (dbcsCode !== undefined) { // Write beginning of the sequence.
+            if (dbcsCode < 0x100) {
+                newBuf[j++] = dbcsCode;
+            }
+            else {
+                newBuf[j++] = dbcsCode >> 8;   // high byte
+                newBuf[j++] = dbcsCode & 0xFF; // low byte
+            }
+        } else {
+            // See todo above.
+        }
+        this.seqObj = undefined;
+    }
+
+    if (this.leadSurrogate !== -1) {
+        // Incomplete surrogate pair - only lead surrogate found.
+        newBuf[j++] = this.defaultCharSingleByte;
+        this.leadSurrogate = -1;
+    }
+    
+    return newBuf.slice(0, j);
+}
+
+// Export for testing
+DBCSEncoder.prototype.findIdx = findIdx;
+
+
+// == Decoder ==================================================================
+
+function DBCSDecoder(options, codec) {
+    // Decoder state
+    this.nodeIdx = 0;
+    this.prevBuf = Buffer.alloc(0);
+
+    // Static data
+    this.decodeTables = codec.decodeTables;
+    this.decodeTableSeq = codec.decodeTableSeq;
+    this.defaultCharUnicode = codec.defaultCharUnicode;
+    this.gb18030 = codec.gb18030;
+}
+
+DBCSDecoder.prototype.write = function(buf) {
+    var newBuf = Buffer.alloc(buf.length*2),
+        nodeIdx = this.nodeIdx, 
+        prevBuf = this.prevBuf, prevBufOffset = this.prevBuf.length,
+        seqStart = -this.prevBuf.length, // idx of the start of current parsed sequence.
+        uCode;
+
+    if (prevBufOffset > 0) // Make prev buf overlap a little to make it easier to slice later.
+        prevBuf = Buffer.concat([prevBuf, buf.slice(0, 10)]);
+    
+    for (var i = 0, j = 0; i < buf.length; i++) {
+        var curByte = (i >= 0) ? buf[i] : prevBuf[i + prevBufOffset];
+
+        // Lookup in current trie node.
+        var uCode = this.decodeTables[nodeIdx][curByte];
+
+        if (uCode >= 0) { 
+            // Normal character, just use it.
+        }
+        else if (uCode === UNASSIGNED) { // Unknown char.
+            // TODO: Callback with seq.
+            //var curSeq = (seqStart >= 0) ? buf.slice(seqStart, i+1) : prevBuf.slice(seqStart + prevBufOffset, i+1 + prevBufOffset);
+            i = seqStart; // Try to parse again, after skipping first byte of the sequence ('i' will be incremented by 'for' cycle).
+            uCode = this.defaultCharUnicode.charCodeAt(0);
+        }
+        else if (uCode === GB18030_CODE) {
+            var curSeq = (seqStart >= 0) ? buf.slice(seqStart, i+1) : prevBuf.slice(seqStart + prevBufOffset, i+1 + prevBufOffset);
+            var ptr = (curSeq[0]-0x81)*12600 + (curSeq[1]-0x30)*1260 + (curSeq[2]-0x81)*10 + (curSeq[3]-0x30);
+            var idx = findIdx(this.gb18030.gbChars, ptr);
+            uCode = this.gb18030.uChars[idx] + ptr - this.gb18030.gbChars[idx];
+        }
+        else if (uCode <= NODE_START) { // Go to next trie node.
+            nodeIdx = NODE_START - uCode;
+            continue;
+        }
+        else if (uCode <= SEQ_START) { // Output a sequence of chars.
+            var seq = this.decodeTableSeq[SEQ_START - uCode];
+            for (var k = 0; k < seq.length - 1; k++) {
+                uCode = seq[k];
+                newBuf[j++] = uCode & 0xFF;
+                newBuf[j++] = uCode >> 8;
+            }
+            uCode = seq[seq.length-1];
+        }
+        else
+            throw new Error("iconv-lite internal error: invalid decoding table value " + uCode + " at " + nodeIdx + "/" + curByte);
+
+        // Write the character to buffer, handling higher planes using surrogate pair.
+        if (uCode > 0xFFFF) { 
+            uCode -= 0x10000;
+            var uCodeLead = 0xD800 + Math.floor(uCode / 0x400);
+            newBuf[j++] = uCodeLead & 0xFF;
+            newBuf[j++] = uCodeLead >> 8;
+
+            uCode = 0xDC00 + uCode % 0x400;
+        }
+        newBuf[j++] = uCode & 0xFF;
+        newBuf[j++] = uCode >> 8;
+
+        // Reset trie node.
+        nodeIdx = 0; seqStart = i+1;
+    }
+
+    this.nodeIdx = nodeIdx;
+    this.prevBuf = (seqStart >= 0) ? buf.slice(seqStart) : prevBuf.slice(seqStart + prevBufOffset);
+    return newBuf.slice(0, j).toString('ucs2');
+}
+
+DBCSDecoder.prototype.end = function() {
+    var ret = '';
+
+    // Try to parse all remaining chars.
+    while (this.prevBuf.length > 0) {
+        // Skip 1 character in the buffer.
+        ret += this.defaultCharUnicode;
+        var buf = this.prevBuf.slice(1);
+
+        // Parse remaining as usual.
+        this.prevBuf = Buffer.alloc(0);
+        this.nodeIdx = 0;
+        if (buf.length > 0)
+            ret += this.write(buf);
+    }
+
+    this.nodeIdx = 0;
+    return ret;
+}
+
+// Binary search for GB18030. Returns largest i such that table[i] <= val.
+function findIdx(table, val) {
+    if (table[0] > val)
+        return -1;
+
+    var l = 0, r = table.length;
+    while (l < r-1) { // always table[l] <= val < table[r]
+        var mid = l + Math.floor((r-l+1)/2);
+        if (table[mid] <= val)
+            l = mid;
+        else
+            r = mid;
+    }
+    return l;
+}
+
diff --git a/server/node_modules/iconv-lite/encodings/dbcs-data.js b/server/node_modules/iconv-lite/encodings/dbcs-data.js
new file mode 100644
index 0000000..4b61914
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/dbcs-data.js
@@ -0,0 +1,176 @@
+"use strict";
+
+// Description of supported double byte encodings and aliases.
+// Tables are not require()-d until they are needed to speed up library load.
+// require()-s are direct to support Browserify.
+
+module.exports = {
+    
+    // == Japanese/ShiftJIS ====================================================
+    // All japanese encodings are based on JIS X set of standards:
+    // JIS X 0201 - Single-byte encoding of ASCII + ¥ + Kana chars at 0xA1-0xDF.
+    // JIS X 0208 - Main set of 6879 characters, placed in 94x94 plane, to be encoded by 2 bytes. 
+    //              Has several variations in 1978, 1983, 1990 and 1997.
+    // JIS X 0212 - Supplementary plane of 6067 chars in 94x94 plane. 1990. Effectively dead.
+    // JIS X 0213 - Extension and modern replacement of 0208 and 0212. Total chars: 11233.
+    //              2 planes, first is superset of 0208, second - revised 0212.
+    //              Introduced in 2000, revised 2004. Some characters are in Unicode Plane 2 (0x2xxxx)
+
+    // Byte encodings are:
+    //  * Shift_JIS: Compatible with 0201, uses not defined chars in top half as lead bytes for double-byte
+    //               encoding of 0208. Lead byte ranges: 0x81-0x9F, 0xE0-0xEF; Trail byte ranges: 0x40-0x7E, 0x80-0x9E, 0x9F-0xFC.
+    //               Windows CP932 is a superset of Shift_JIS. Some companies added more chars, notably KDDI.
+    //  * EUC-JP:    Up to 3 bytes per character. Used mostly on *nixes.
+    //               0x00-0x7F       - lower part of 0201
+    //               0x8E, 0xA1-0xDF - upper part of 0201
+    //               (0xA1-0xFE)x2   - 0208 plane (94x94).
+    //               0x8F, (0xA1-0xFE)x2 - 0212 plane (94x94).
+    //  * JIS X 208: 7-bit, direct encoding of 0208. Byte ranges: 0x21-0x7E (94 values). Uncommon.
+    //               Used as-is in ISO2022 family.
+    //  * ISO2022-JP: Stateful encoding, with escape sequences to switch between ASCII, 
+    //                0201-1976 Roman, 0208-1978, 0208-1983.
+    //  * ISO2022-JP-1: Adds esc seq for 0212-1990.
+    //  * ISO2022-JP-2: Adds esc seq for GB2313-1980, KSX1001-1992, ISO8859-1, ISO8859-7.
+    //  * ISO2022-JP-3: Adds esc seq for 0201-1976 Kana set, 0213-2000 Planes 1, 2.
+    //  * ISO2022-JP-2004: Adds 0213-2004 Plane 1.
+    //
+    // After JIS X 0213 appeared, Shift_JIS-2004, EUC-JISX0213 and ISO2022-JP-2004 followed, with just changing the planes.
+    //
+    // Overall, it seems that it's a mess :( http://www8.plala.or.jp/tkubota1/unicode-symbols-map2.html
+
+    'shiftjis': {
+        type: '_dbcs',
+        table: function() { return require('./tables/shiftjis.json') },
+        encodeAdd: {'\u00a5': 0x5C, '\u203E': 0x7E},
+        encodeSkipVals: [{from: 0xED40, to: 0xF940}],
+    },
+    'csshiftjis': 'shiftjis',
+    'mskanji': 'shiftjis',
+    'sjis': 'shiftjis',
+    'windows31j': 'shiftjis',
+    'ms31j': 'shiftjis',
+    'xsjis': 'shiftjis',
+    'windows932': 'shiftjis',
+    'ms932': 'shiftjis',
+    '932': 'shiftjis',
+    'cp932': 'shiftjis',
+
+    'eucjp': {
+        type: '_dbcs',
+        table: function() { return require('./tables/eucjp.json') },
+        encodeAdd: {'\u00a5': 0x5C, '\u203E': 0x7E},
+    },
+
+    // TODO: KDDI extension to Shift_JIS
+    // TODO: IBM CCSID 942 = CP932, but F0-F9 custom chars and other char changes.
+    // TODO: IBM CCSID 943 = Shift_JIS = CP932 with original Shift_JIS lower 128 chars.
+
+
+    // == Chinese/GBK ==========================================================
+    // http://en.wikipedia.org/wiki/GBK
+    // We mostly implement W3C recommendation: https://www.w3.org/TR/encoding/#gbk-encoder
+
+    // Oldest GB2312 (1981, ~7600 chars) is a subset of CP936
+    'gb2312': 'cp936',
+    'gb231280': 'cp936',
+    'gb23121980': 'cp936',
+    'csgb2312': 'cp936',
+    'csiso58gb231280': 'cp936',
+    'euccn': 'cp936',
+
+    // Microsoft's CP936 is a subset and approximation of GBK.
+    'windows936': 'cp936',
+    'ms936': 'cp936',
+    '936': 'cp936',
+    'cp936': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp936.json') },
+    },
+
+    // GBK (~22000 chars) is an extension of CP936 that added user-mapped chars and some other.
+    'gbk': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp936.json').concat(require('./tables/gbk-added.json')) },
+    },
+    'xgbk': 'gbk',
+    'isoir58': 'gbk',
+
+    // GB18030 is an algorithmic extension of GBK.
+    // Main source: https://www.w3.org/TR/encoding/#gbk-encoder
+    // http://icu-project.org/docs/papers/gb18030.html
+    // http://source.icu-project.org/repos/icu/data/trunk/charset/data/xml/gb-18030-2000.xml
+    // http://www.khngai.com/chinese/charmap/tblgbk.php?page=0
+    'gb18030': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp936.json').concat(require('./tables/gbk-added.json')) },
+        gb18030: function() { return require('./tables/gb18030-ranges.json') },
+        encodeSkipVals: [0x80],
+        encodeAdd: {'€': 0xA2E3},
+    },
+
+    'chinese': 'gb18030',
+
+
+    // == Korean ===============================================================
+    // EUC-KR, KS_C_5601 and KS X 1001 are exactly the same.
+    'windows949': 'cp949',
+    'ms949': 'cp949',
+    '949': 'cp949',
+    'cp949': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp949.json') },
+    },
+
+    'cseuckr': 'cp949',
+    'csksc56011987': 'cp949',
+    'euckr': 'cp949',
+    'isoir149': 'cp949',
+    'korean': 'cp949',
+    'ksc56011987': 'cp949',
+    'ksc56011989': 'cp949',
+    'ksc5601': 'cp949',
+
+
+    // == Big5/Taiwan/Hong Kong ================================================
+    // There are lots of tables for Big5 and cp950. Please see the following links for history:
+    // http://moztw.org/docs/big5/  http://www.haible.de/bruno/charsets/conversion-tables/Big5.html
+    // Variations, in roughly number of defined chars:
+    //  * Windows CP 950: Microsoft variant of Big5. Canonical: http://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP950.TXT
+    //  * Windows CP 951: Microsoft variant of Big5-HKSCS-2001. Seems to be never public. http://me.abelcheung.org/articles/research/what-is-cp951/
+    //  * Big5-2003 (Taiwan standard) almost superset of cp950.
+    //  * Unicode-at-on (UAO) / Mozilla 1.8. Falling out of use on the Web. Not supported by other browsers.
+    //  * Big5-HKSCS (-2001, -2004, -2008). Hong Kong standard. 
+    //    many unicode code points moved from PUA to Supplementary plane (U+2XXXX) over the years.
+    //    Plus, it has 4 combining sequences.
+    //    Seems that Mozilla refused to support it for 10 yrs. https://bugzilla.mozilla.org/show_bug.cgi?id=162431 https://bugzilla.mozilla.org/show_bug.cgi?id=310299
+    //    because big5-hkscs is the only encoding to include astral characters in non-algorithmic way.
+    //    Implementations are not consistent within browsers; sometimes labeled as just big5.
+    //    MS Internet Explorer switches from big5 to big5-hkscs when a patch applied.
+    //    Great discussion & recap of what's going on https://bugzilla.mozilla.org/show_bug.cgi?id=912470#c31
+    //    In the encoder, it might make sense to support encoding old PUA mappings to Big5 bytes seq-s.
+    //    Official spec: http://www.ogcio.gov.hk/en/business/tech_promotion/ccli/terms/doc/2003cmp_2008.txt
+    //                   http://www.ogcio.gov.hk/tc/business/tech_promotion/ccli/terms/doc/hkscs-2008-big5-iso.txt
+    // 
+    // Current understanding of how to deal with Big5(-HKSCS) is in the Encoding Standard, http://encoding.spec.whatwg.org/#big5-encoder
+    // Unicode mapping (http://www.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/OTHER/BIG5.TXT) is said to be wrong.
+
+    'windows950': 'cp950',
+    'ms950': 'cp950',
+    '950': 'cp950',
+    'cp950': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp950.json') },
+    },
+
+    // Big5 has many variations and is an extension of cp950. We use Encoding Standard's as a consensus.
+    'big5': 'big5hkscs',
+    'big5hkscs': {
+        type: '_dbcs',
+        table: function() { return require('./tables/cp950.json').concat(require('./tables/big5-added.json')) },
+        encodeSkipVals: [0xa2cc],
+    },
+
+    'cnbig5': 'big5hkscs',
+    'csbig5': 'big5hkscs',
+    'xxbig5': 'big5hkscs',
+};
diff --git a/server/node_modules/iconv-lite/encodings/index.js b/server/node_modules/iconv-lite/encodings/index.js
new file mode 100644
index 0000000..e304003
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/index.js
@@ -0,0 +1,22 @@
+"use strict";
+
+// Update this array if you add/rename/remove files in this directory.
+// We support Browserify by skipping automatic module discovery and requiring modules directly.
+var modules = [
+    require("./internal"),
+    require("./utf16"),
+    require("./utf7"),
+    require("./sbcs-codec"),
+    require("./sbcs-data"),
+    require("./sbcs-data-generated"),
+    require("./dbcs-codec"),
+    require("./dbcs-data"),
+];
+
+// Put all encoding/alias/codec definitions to single object and export it. 
+for (var i = 0; i < modules.length; i++) {
+    var module = modules[i];
+    for (var enc in module)
+        if (Object.prototype.hasOwnProperty.call(module, enc))
+            exports[enc] = module[enc];
+}
diff --git a/server/node_modules/iconv-lite/encodings/internal.js b/server/node_modules/iconv-lite/encodings/internal.js
new file mode 100644
index 0000000..05ce38b
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/internal.js
@@ -0,0 +1,188 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// Export Node.js internal encodings.
+
+module.exports = {
+    // Encodings
+    utf8:   { type: "_internal", bomAware: true},
+    cesu8:  { type: "_internal", bomAware: true},
+    unicode11utf8: "utf8",
+
+    ucs2:   { type: "_internal", bomAware: true},
+    utf16le: "ucs2",
+
+    binary: { type: "_internal" },
+    base64: { type: "_internal" },
+    hex:    { type: "_internal" },
+
+    // Codec.
+    _internal: InternalCodec,
+};
+
+//------------------------------------------------------------------------------
+
+function InternalCodec(codecOptions, iconv) {
+    this.enc = codecOptions.encodingName;
+    this.bomAware = codecOptions.bomAware;
+
+    if (this.enc === "base64")
+        this.encoder = InternalEncoderBase64;
+    else if (this.enc === "cesu8") {
+        this.enc = "utf8"; // Use utf8 for decoding.
+        this.encoder = InternalEncoderCesu8;
+
+        // Add decoder for versions of Node not supporting CESU-8
+        if (Buffer.from('eda0bdedb2a9', 'hex').toString() !== '💩') {
+            this.decoder = InternalDecoderCesu8;
+            this.defaultCharUnicode = iconv.defaultCharUnicode;
+        }
+    }
+}
+
+InternalCodec.prototype.encoder = InternalEncoder;
+InternalCodec.prototype.decoder = InternalDecoder;
+
+//------------------------------------------------------------------------------
+
+// We use node.js internal decoder. Its signature is the same as ours.
+var StringDecoder = require('string_decoder').StringDecoder;
+
+if (!StringDecoder.prototype.end) // Node v0.8 doesn't have this method.
+    StringDecoder.prototype.end = function() {};
+
+
+function InternalDecoder(options, codec) {
+    StringDecoder.call(this, codec.enc);
+}
+
+InternalDecoder.prototype = StringDecoder.prototype;
+
+
+//------------------------------------------------------------------------------
+// Encoder is mostly trivial
+
+function InternalEncoder(options, codec) {
+    this.enc = codec.enc;
+}
+
+InternalEncoder.prototype.write = function(str) {
+    return Buffer.from(str, this.enc);
+}
+
+InternalEncoder.prototype.end = function() {
+}
+
+
+//------------------------------------------------------------------------------
+// Except base64 encoder, which must keep its state.
+
+function InternalEncoderBase64(options, codec) {
+    this.prevStr = '';
+}
+
+InternalEncoderBase64.prototype.write = function(str) {
+    str = this.prevStr + str;
+    var completeQuads = str.length - (str.length % 4);
+    this.prevStr = str.slice(completeQuads);
+    str = str.slice(0, completeQuads);
+
+    return Buffer.from(str, "base64");
+}
+
+InternalEncoderBase64.prototype.end = function() {
+    return Buffer.from(this.prevStr, "base64");
+}
+
+
+//------------------------------------------------------------------------------
+// CESU-8 encoder is also special.
+
+function InternalEncoderCesu8(options, codec) {
+}
+
+InternalEncoderCesu8.prototype.write = function(str) {
+    var buf = Buffer.alloc(str.length * 3), bufIdx = 0;
+    for (var i = 0; i < str.length; i++) {
+        var charCode = str.charCodeAt(i);
+        // Naive implementation, but it works because CESU-8 is especially easy
+        // to convert from UTF-16 (which all JS strings are encoded in).
+        if (charCode < 0x80)
+            buf[bufIdx++] = charCode;
+        else if (charCode < 0x800) {
+            buf[bufIdx++] = 0xC0 + (charCode >>> 6);
+            buf[bufIdx++] = 0x80 + (charCode & 0x3f);
+        }
+        else { // charCode will always be < 0x10000 in javascript.
+            buf[bufIdx++] = 0xE0 + (charCode >>> 12);
+            buf[bufIdx++] = 0x80 + ((charCode >>> 6) & 0x3f);
+            buf[bufIdx++] = 0x80 + (charCode & 0x3f);
+        }
+    }
+    return buf.slice(0, bufIdx);
+}
+
+InternalEncoderCesu8.prototype.end = function() {
+}
+
+//------------------------------------------------------------------------------
+// CESU-8 decoder is not implemented in Node v4.0+
+
+function InternalDecoderCesu8(options, codec) {
+    this.acc = 0;
+    this.contBytes = 0;
+    this.accBytes = 0;
+    this.defaultCharUnicode = codec.defaultCharUnicode;
+}
+
+InternalDecoderCesu8.prototype.write = function(buf) {
+    var acc = this.acc, contBytes = this.contBytes, accBytes = this.accBytes, 
+        res = '';
+    for (var i = 0; i < buf.length; i++) {
+        var curByte = buf[i];
+        if ((curByte & 0xC0) !== 0x80) { // Leading byte
+            if (contBytes > 0) { // Previous code is invalid
+                res += this.defaultCharUnicode;
+                contBytes = 0;
+            }
+
+            if (curByte < 0x80) { // Single-byte code
+                res += String.fromCharCode(curByte);
+            } else if (curByte < 0xE0) { // Two-byte code
+                acc = curByte & 0x1F;
+                contBytes = 1; accBytes = 1;
+            } else if (curByte < 0xF0) { // Three-byte code
+                acc = curByte & 0x0F;
+                contBytes = 2; accBytes = 1;
+            } else { // Four or more are not supported for CESU-8.
+                res += this.defaultCharUnicode;
+            }
+        } else { // Continuation byte
+            if (contBytes > 0) { // We're waiting for it.
+                acc = (acc << 6) | (curByte & 0x3f);
+                contBytes--; accBytes++;
+                if (contBytes === 0) {
+                    // Check for overlong encoding, but support Modified UTF-8 (encoding NULL as C0 80)
+                    if (accBytes === 2 && acc < 0x80 && acc > 0)
+                        res += this.defaultCharUnicode;
+                    else if (accBytes === 3 && acc < 0x800)
+                        res += this.defaultCharUnicode;
+                    else
+                        // Actually add character.
+                        res += String.fromCharCode(acc);
+                }
+            } else { // Unexpected continuation byte
+                res += this.defaultCharUnicode;
+            }
+        }
+    }
+    this.acc = acc; this.contBytes = contBytes; this.accBytes = accBytes;
+    return res;
+}
+
+InternalDecoderCesu8.prototype.end = function() {
+    var res = 0;
+    if (this.contBytes > 0)
+        res += this.defaultCharUnicode;
+    return res;
+}
diff --git a/server/node_modules/iconv-lite/encodings/sbcs-codec.js b/server/node_modules/iconv-lite/encodings/sbcs-codec.js
new file mode 100644
index 0000000..abac5ff
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/sbcs-codec.js
@@ -0,0 +1,72 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// Single-byte codec. Needs a 'chars' string parameter that contains 256 or 128 chars that
+// correspond to encoded bytes (if 128 - then lower half is ASCII). 
+
+exports._sbcs = SBCSCodec;
+function SBCSCodec(codecOptions, iconv) {
+    if (!codecOptions)
+        throw new Error("SBCS codec is called without the data.")
+    
+    // Prepare char buffer for decoding.
+    if (!codecOptions.chars || (codecOptions.chars.length !== 128 && codecOptions.chars.length !== 256))
+        throw new Error("Encoding '"+codecOptions.type+"' has incorrect 'chars' (must be of len 128 or 256)");
+    
+    if (codecOptions.chars.length === 128) {
+        var asciiString = "";
+        for (var i = 0; i < 128; i++)
+            asciiString += String.fromCharCode(i);
+        codecOptions.chars = asciiString + codecOptions.chars;
+    }
+
+    this.decodeBuf = Buffer.from(codecOptions.chars, 'ucs2');
+    
+    // Encoding buffer.
+    var encodeBuf = Buffer.alloc(65536, iconv.defaultCharSingleByte.charCodeAt(0));
+
+    for (var i = 0; i < codecOptions.chars.length; i++)
+        encodeBuf[codecOptions.chars.charCodeAt(i)] = i;
+
+    this.encodeBuf = encodeBuf;
+}
+
+SBCSCodec.prototype.encoder = SBCSEncoder;
+SBCSCodec.prototype.decoder = SBCSDecoder;
+
+
+function SBCSEncoder(options, codec) {
+    this.encodeBuf = codec.encodeBuf;
+}
+
+SBCSEncoder.prototype.write = function(str) {
+    var buf = Buffer.alloc(str.length);
+    for (var i = 0; i < str.length; i++)
+        buf[i] = this.encodeBuf[str.charCodeAt(i)];
+    
+    return buf;
+}
+
+SBCSEncoder.prototype.end = function() {
+}
+
+
+function SBCSDecoder(options, codec) {
+    this.decodeBuf = codec.decodeBuf;
+}
+
+SBCSDecoder.prototype.write = function(buf) {
+    // Strings are immutable in JS -> we use ucs2 buffer to speed up computations.
+    var decodeBuf = this.decodeBuf;
+    var newBuf = Buffer.alloc(buf.length*2);
+    var idx1 = 0, idx2 = 0;
+    for (var i = 0; i < buf.length; i++) {
+        idx1 = buf[i]*2; idx2 = i*2;
+        newBuf[idx2] = decodeBuf[idx1];
+        newBuf[idx2+1] = decodeBuf[idx1+1];
+    }
+    return newBuf.toString('ucs2');
+}
+
+SBCSDecoder.prototype.end = function() {
+}
diff --git a/server/node_modules/iconv-lite/encodings/sbcs-data-generated.js b/server/node_modules/iconv-lite/encodings/sbcs-data-generated.js
new file mode 100644
index 0000000..9b48236
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/sbcs-data-generated.js
@@ -0,0 +1,451 @@
+"use strict";
+
+// Generated data for sbcs codec. Don't edit manually. Regenerate using generation/gen-sbcs.js script.
+module.exports = {
+  "437": "cp437",
+  "737": "cp737",
+  "775": "cp775",
+  "850": "cp850",
+  "852": "cp852",
+  "855": "cp855",
+  "856": "cp856",
+  "857": "cp857",
+  "858": "cp858",
+  "860": "cp860",
+  "861": "cp861",
+  "862": "cp862",
+  "863": "cp863",
+  "864": "cp864",
+  "865": "cp865",
+  "866": "cp866",
+  "869": "cp869",
+  "874": "windows874",
+  "922": "cp922",
+  "1046": "cp1046",
+  "1124": "cp1124",
+  "1125": "cp1125",
+  "1129": "cp1129",
+  "1133": "cp1133",
+  "1161": "cp1161",
+  "1162": "cp1162",
+  "1163": "cp1163",
+  "1250": "windows1250",
+  "1251": "windows1251",
+  "1252": "windows1252",
+  "1253": "windows1253",
+  "1254": "windows1254",
+  "1255": "windows1255",
+  "1256": "windows1256",
+  "1257": "windows1257",
+  "1258": "windows1258",
+  "28591": "iso88591",
+  "28592": "iso88592",
+  "28593": "iso88593",
+  "28594": "iso88594",
+  "28595": "iso88595",
+  "28596": "iso88596",
+  "28597": "iso88597",
+  "28598": "iso88598",
+  "28599": "iso88599",
+  "28600": "iso885910",
+  "28601": "iso885911",
+  "28603": "iso885913",
+  "28604": "iso885914",
+  "28605": "iso885915",
+  "28606": "iso885916",
+  "windows874": {
+    "type": "_sbcs",
+    "chars": "€����…�����������‘’“”•–—�������� กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู����฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛����"
+  },
+  "win874": "windows874",
+  "cp874": "windows874",
+  "windows1250": {
+    "type": "_sbcs",
+    "chars": "€�‚�„…†‡�‰Š‹ŚŤŽŹ�‘’“”•–—�™š›śťžź ˇ˘Ł¤Ą¦§¨©Ş«¬®Ż°±˛ł´µ¶·¸ąş»Ľ˝ľżŔÁÂĂÄĹĆÇČÉĘËĚÍÎĎĐŃŇÓÔŐÖ×ŘŮÚŰÜÝŢßŕáâăäĺćçčéęëěíîďđńňóôőö÷řůúűüýţ˙"
+  },
+  "win1250": "windows1250",
+  "cp1250": "windows1250",
+  "windows1251": {
+    "type": "_sbcs",
+    "chars": "ЂЃ‚ѓ„…†‡€‰Љ‹ЊЌЋЏђ‘’“”•–—�™љ›њќћџ ЎўЈ¤Ґ¦§Ё©Є«¬®Ї°±Ііґµ¶·ё№є»јЅѕїАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя"
+  },
+  "win1251": "windows1251",
+  "cp1251": "windows1251",
+  "windows1252": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡ˆ‰Š‹Œ�Ž��‘’“”•–—˜™š›œ�žŸ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "win1252": "windows1252",
+  "cp1252": "windows1252",
+  "windows1253": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡�‰�‹�����‘’“”•–—�™�›���� ΅Ά£¤¥¦§¨©�«¬®―°±²³΄µ¶·ΈΉΊ»Ό½ΎΏΐΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡ�ΣΤΥΦΧΨΩΪΫάέήίΰαβγδεζηθικλμνξοπρςστυφχψωϊϋόύώ�"
+  },
+  "win1253": "windows1253",
+  "cp1253": "windows1253",
+  "windows1254": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡ˆ‰Š‹Œ����‘’“”•–—˜™š›œ��Ÿ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏĞÑÒÓÔÕÖ×ØÙÚÛÜİŞßàáâãäåæçèéêëìíîïğñòóôõö÷øùúûüışÿ"
+  },
+  "win1254": "windows1254",
+  "cp1254": "windows1254",
+  "windows1255": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡ˆ‰�‹�����‘’“”•–—˜™�›���� ¡¢£₪¥¦§¨©×«¬®¯°±²³´µ¶·¸¹÷»¼½¾¿ְֱֲֳִֵֶַָֹֺֻּֽ־ֿ׀ׁׂ׃װױײ׳״�������אבגדהוזחטיךכלםמןנסעףפץצקרשת��‎‏�"
+  },
+  "win1255": "windows1255",
+  "cp1255": "windows1255",
+  "windows1256": {
+    "type": "_sbcs",
+    "chars": "€پ‚ƒ„…†‡ˆ‰ٹ‹Œچژڈگ‘’“”•–—ک™ڑ›œ‌‍ں ،¢£¤¥¦§¨©ھ«¬®¯°±²³´µ¶·¸¹؛»¼½¾؟ہءآأؤإئابةتثجحخدذرزسشصض×طظعغـفقكàلâمنهوçèéêëىيîïًٌٍَôُِ÷ّùْûü‎‏ے"
+  },
+  "win1256": "windows1256",
+  "cp1256": "windows1256",
+  "windows1257": {
+    "type": "_sbcs",
+    "chars": "€�‚�„…†‡�‰�‹�¨ˇ¸�‘’“”•–—�™�›�¯˛� �¢£¤�¦§Ø©Ŗ«¬®Æ°±²³´µ¶·ø¹ŗ»¼½¾æĄĮĀĆÄÅĘĒČÉŹĖĢĶĪĻŠŃŅÓŌÕÖ×ŲŁŚŪÜŻŽßąįāćäåęēčéźėģķīļšńņóōõö÷ųłśūüżž˙"
+  },
+  "win1257": "windows1257",
+  "cp1257": "windows1257",
+  "windows1258": {
+    "type": "_sbcs",
+    "chars": "€�‚ƒ„…†‡ˆ‰�‹Œ����‘’“”•–—˜™�›œ��Ÿ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂĂÄÅÆÇÈÉÊË̀ÍÎÏĐÑ̉ÓÔƠÖ×ØÙÚÛÜỮßàáâăäåæçèéêë́íîïđṇ̃óôơö÷øùúûüư₫ÿ"
+  },
+  "win1258": "windows1258",
+  "cp1258": "windows1258",
+  "iso88591": {
+    "type": "_sbcs",
+    "chars": " ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "cp28591": "iso88591",
+  "iso88592": {
+    "type": "_sbcs",
+    "chars": " Ą˘Ł¤ĽŚ§¨ŠŞŤŹŽŻ°ą˛ł´ľśˇ¸šşťź˝žżŔÁÂĂÄĹĆÇČÉĘËĚÍÎĎĐŃŇÓÔŐÖ×ŘŮÚŰÜÝŢßŕáâăäĺćçčéęëěíîďđńňóôőö÷řůúűüýţ˙"
+  },
+  "cp28592": "iso88592",
+  "iso88593": {
+    "type": "_sbcs",
+    "chars": " Ħ˘£¤�Ĥ§¨İŞĞĴ�Ż°ħ²³´µĥ·¸ışğĵ½�żÀÁÂ�ÄĊĈÇÈÉÊËÌÍÎÏ�ÑÒÓÔĠÖ×ĜÙÚÛÜŬŜßàáâ�äċĉçèéêëìíîï�ñòóôġö÷ĝùúûüŭŝ˙"
+  },
+  "cp28593": "iso88593",
+  "iso88594": {
+    "type": "_sbcs",
+    "chars": " ĄĸŖ¤ĨĻ§¨ŠĒĢŦŽ¯°ą˛ŗ´ĩļˇ¸šēģŧŊžŋĀÁÂÃÄÅÆĮČÉĘËĖÍÎĪĐŅŌĶÔÕÖ×ØŲÚÛÜŨŪßāáâãäåæįčéęëėíîīđņōķôõö÷øųúûüũū˙"
+  },
+  "cp28594": "iso88594",
+  "iso88595": {
+    "type": "_sbcs",
+    "chars": " ЁЂЃЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя№ёђѓєѕіїјљњћќ§ўџ"
+  },
+  "cp28595": "iso88595",
+  "iso88596": {
+    "type": "_sbcs",
+    "chars": " ���¤�������،�������������؛���؟�ءآأؤإئابةتثجحخدذرزسشصضطظعغ�����ـفقكلمنهوىيًٌٍَُِّْ�������������"
+  },
+  "cp28596": "iso88596",
+  "iso88597": {
+    "type": "_sbcs",
+    "chars": " ‘’£€₯¦§¨©ͺ«¬�―°±²³΄΅Ά·ΈΉΊ»Ό½ΎΏΐΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡ�ΣΤΥΦΧΨΩΪΫάέήίΰαβγδεζηθικλμνξοπρςστυφχψωϊϋόύώ�"
+  },
+  "cp28597": "iso88597",
+  "iso88598": {
+    "type": "_sbcs",
+    "chars": " �¢£¤¥¦§¨©×«¬®¯°±²³´µ¶·¸¹÷»¼½¾��������������������������������‗אבגדהוזחטיךכלםמןנסעףפץצקרשת��‎‏�"
+  },
+  "cp28598": "iso88598",
+  "iso88599": {
+    "type": "_sbcs",
+    "chars": " ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏĞÑÒÓÔÕÖ×ØÙÚÛÜİŞßàáâãäåæçèéêëìíîïğñòóôõö÷øùúûüışÿ"
+  },
+  "cp28599": "iso88599",
+  "iso885910": {
+    "type": "_sbcs",
+    "chars": " ĄĒĢĪĨĶ§ĻĐŠŦŽŪŊ°ąēģīĩķ·ļđšŧž―ūŋĀÁÂÃÄÅÆĮČÉĘËĖÍÎÏÐŅŌÓÔÕÖŨØŲÚÛÜÝÞßāáâãäåæįčéęëėíîïðņōóôõöũøųúûüýþĸ"
+  },
+  "cp28600": "iso885910",
+  "iso885911": {
+    "type": "_sbcs",
+    "chars": " กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู����฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛����"
+  },
+  "cp28601": "iso885911",
+  "iso885913": {
+    "type": "_sbcs",
+    "chars": " ”¢£¤„¦§Ø©Ŗ«¬®Æ°±²³“µ¶·ø¹ŗ»¼½¾æĄĮĀĆÄÅĘĒČÉŹĖĢĶĪĻŠŃŅÓŌÕÖ×ŲŁŚŪÜŻŽßąįāćäåęēčéźėģķīļšńņóōõö÷ųłśūüżž’"
+  },
+  "cp28603": "iso885913",
+  "iso885914": {
+    "type": "_sbcs",
+    "chars": " Ḃḃ£ĊċḊ§Ẁ©ẂḋỲ®ŸḞḟĠġṀṁ¶ṖẁṗẃṠỳẄẅṡÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏŴÑÒÓÔÕÖṪØÙÚÛÜÝŶßàáâãäåæçèéêëìíîïŵñòóôõöṫøùúûüýŷÿ"
+  },
+  "cp28604": "iso885914",
+  "iso885915": {
+    "type": "_sbcs",
+    "chars": " ¡¢£€¥Š§š©ª«¬®¯°±²³Žµ¶·ž¹º»ŒœŸ¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "cp28605": "iso885915",
+  "iso885916": {
+    "type": "_sbcs",
+    "chars": " ĄąŁ€„Š§š©Ș«ŹźŻ°±ČłŽ”¶·žčș»ŒœŸżÀÁÂĂÄĆÆÇÈÉÊËÌÍÎÏĐŃÒÓÔŐÖŚŰÙÚÛÜĘȚßàáâăäćæçèéêëìíîïđńòóôőöśűùúûüęțÿ"
+  },
+  "cp28606": "iso885916",
+  "cp437": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£¥₧ƒáíóúñÑªº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm437": "cp437",
+  "csibm437": "cp437",
+  "cp737": {
+    "type": "_sbcs",
+    "chars": "ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩαβγδεζηθικλμνξοπρσςτυφχψ░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀ωάέήϊίόύϋώΆΈΉΊΌΎΏ±≥≤ΪΫ÷≈°∙·√ⁿ²■ "
+  },
+  "ibm737": "cp737",
+  "csibm737": "cp737",
+  "cp775": {
+    "type": "_sbcs",
+    "chars": "ĆüéāäģåćłēŖŗīŹÄÅÉæÆōöĢ¢ŚśÖÜø£Ø×¤ĀĪóŻżź”¦©®¬½¼Ł«»░▒▓│┤ĄČĘĖ╣║╗╝ĮŠ┐└┴┬├─┼ŲŪ╚╔╩╦╠═╬Žąčęėįšųūž┘┌█▄▌▐▀ÓßŌŃõÕµńĶķĻļņĒŅ’±“¾¶§÷„°∙·¹³²■ "
+  },
+  "ibm775": "cp775",
+  "csibm775": "cp775",
+  "cp850": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜø£Ø×ƒáíóúñÑªº¿®¬½¼¡«»░▒▓│┤ÁÂÀ©╣║╗╝¢¥┐└┴┬├─┼ãÃ╚╔╩╦╠═╬¤ðÐÊËÈıÍÎÏ┘┌█▄¦Ì▀ÓßÔÒõÕµþÞÚÛÙýÝ¯´±‗¾¶§÷¸°¨·¹³²■ "
+  },
+  "ibm850": "cp850",
+  "csibm850": "cp850",
+  "cp852": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäůćçłëŐőîŹÄĆÉĹĺôöĽľŚśÖÜŤťŁ×čáíóúĄąŽžĘę¬źČş«»░▒▓│┤ÁÂĚŞ╣║╗╝Żż┐└┴┬├─┼Ăă╚╔╩╦╠═╬¤đĐĎËďŇÍÎě┘┌█▄ŢŮ▀ÓßÔŃńňŠšŔÚŕŰýÝţ´˝˛ˇ˘§÷¸°¨˙űŘř■ "
+  },
+  "ibm852": "cp852",
+  "csibm852": "cp852",
+  "cp855": {
+    "type": "_sbcs",
+    "chars": "ђЂѓЃёЁєЄѕЅіІїЇјЈљЉњЊћЋќЌўЎџЏюЮъЪаАбБцЦдДеЕфФгГ«»░▒▓│┤хХиИ╣║╗╝йЙ┐└┴┬├─┼кК╚╔╩╦╠═╬¤лЛмМнНоОп┘┌█▄Пя▀ЯрРсСтТуУжЖвВьЬ№ыЫзЗшШэЭщЩчЧ§■ "
+  },
+  "ibm855": "cp855",
+  "csibm855": "cp855",
+  "cp856": {
+    "type": "_sbcs",
+    "chars": "אבגדהוזחטיךכלםמןנסעףפץצקרשת�£�×����������®¬½¼�«»░▒▓│┤���©╣║╗╝¢¥┐└┴┬├─┼��╚╔╩╦╠═╬¤���������┘┌█▄¦�▀������µ�������¯´±‗¾¶§÷¸°¨·¹³²■ "
+  },
+  "ibm856": "cp856",
+  "csibm856": "cp856",
+  "cp857": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîıÄÅÉæÆôöòûùİÖÜø£ØŞşáíóúñÑĞğ¿®¬½¼¡«»░▒▓│┤ÁÂÀ©╣║╗╝¢¥┐└┴┬├─┼ãÃ╚╔╩╦╠═╬¤ºªÊËÈ�ÍÎÏ┘┌█▄¦Ì▀ÓßÔÒõÕµ�×ÚÛÙìÿ¯´±�¾¶§÷¸°¨·¹³²■ "
+  },
+  "ibm857": "cp857",
+  "csibm857": "cp857",
+  "cp858": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜø£Ø×ƒáíóúñÑªº¿®¬½¼¡«»░▒▓│┤ÁÂÀ©╣║╗╝¢¥┐└┴┬├─┼ãÃ╚╔╩╦╠═╬¤ðÐÊËÈ€ÍÎÏ┘┌█▄¦Ì▀ÓßÔÒõÕµþÞÚÛÙýÝ¯´±‗¾¶§÷¸°¨·¹³²■ "
+  },
+  "ibm858": "cp858",
+  "csibm858": "cp858",
+  "cp860": {
+    "type": "_sbcs",
+    "chars": "ÇüéâãàÁçêÊèÍÔìÃÂÉÀÈôõòÚùÌÕÜ¢£Ù₧ÓáíóúñÑªº¿Ò¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm860": "cp860",
+  "csibm860": "cp860",
+  "cp861": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèÐðÞÄÅÉæÆôöþûÝýÖÜø£Ø₧ƒáíóúÁÍÓÚ¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm861": "cp861",
+  "csibm861": "cp861",
+  "cp862": {
+    "type": "_sbcs",
+    "chars": "אבגדהוזחטיךכלםמןנסעףפץצקרשת¢£¥₧ƒáíóúñÑªº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm862": "cp862",
+  "csibm862": "cp862",
+  "cp863": {
+    "type": "_sbcs",
+    "chars": "ÇüéâÂà¶çêëèïî‗À§ÉÈÊôËÏûù¤ÔÜ¢£ÙÛƒ¦´óú¨¸³¯Î⌐¬½¼¾«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm863": "cp863",
+  "csibm863": "cp863",
+  "cp864": {
+    "type": "_sbcs",
+    "chars": "\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f !\"#$٪&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~°·∙√▒─│┼┤┬├┴┐┌└┘β∞φ±½¼≈«»ﻷﻸ��ﻻﻼ� ﺂ£¤ﺄ��ﺎﺏﺕﺙ،ﺝﺡﺥ٠١٢٣٤٥٦٧٨٩ﻑ؛ﺱﺵﺹ؟¢ﺀﺁﺃﺅﻊﺋﺍﺑﺓﺗﺛﺟﺣﺧﺩﺫﺭﺯﺳﺷﺻﺿﻁﻅﻋﻏ¦¬÷×ﻉـﻓﻗﻛﻟﻣﻧﻫﻭﻯﻳﺽﻌﻎﻍﻡﹽّﻥﻩﻬﻰﻲﻐﻕﻵﻶﻝﻙﻱ■�"
+  },
+  "ibm864": "cp864",
+  "csibm864": "cp864",
+  "cp865": {
+    "type": "_sbcs",
+    "chars": "ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜø£Ø₧ƒáíóúñÑªº¿⌐¬½¼¡«¤░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+  },
+  "ibm865": "cp865",
+  "csibm865": "cp865",
+  "cp866": {
+    "type": "_sbcs",
+    "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмноп░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀рстуфхцчшщъыьэюяЁёЄєЇїЎў°∙·√№¤■ "
+  },
+  "ibm866": "cp866",
+  "csibm866": "cp866",
+  "cp869": {
+    "type": "_sbcs",
+    "chars": "������Ά�·¬¦‘’Έ―ΉΊΪΌ��ΎΫ©Ώ²³ά£έήίϊΐόύΑΒΓΔΕΖΗ½ΘΙ«»░▒▓│┤ΚΛΜΝ╣║╗╝ΞΟ┐└┴┬├─┼ΠΡ╚╔╩╦╠═╬ΣΤΥΦΧΨΩαβγ┘┌█▄δε▀ζηθικλμνξοπρσςτ΄±υφχ§ψ΅°¨ωϋΰώ■ "
+  },
+  "ibm869": "cp869",
+  "csibm869": "cp869",
+  "cp922": {
+    "type": "_sbcs",
+    "chars": " ¡¢£¤¥¦§¨©ª«¬®‾°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏŠÑÒÓÔÕÖ×ØÙÚÛÜÝŽßàáâãäåæçèéêëìíîïšñòóôõö÷øùúûüýžÿ"
+  },
+  "ibm922": "cp922",
+  "csibm922": "cp922",
+  "cp1046": {
+    "type": "_sbcs",
+    "chars": "ﺈ×÷ﹱ■│─┐┌└┘ﹹﹻﹽﹿﹷﺊﻰﻳﻲﻎﻏﻐﻶﻸﻺﻼ ¤ﺋﺑﺗﺛﺟﺣ،ﺧﺳ٠١٢٣٤٥٦٧٨٩ﺷ؛ﺻﺿﻊ؟ﻋءآأؤإئابةتثجحخدذرزسشصضطﻇعغﻌﺂﺄﺎﻓـفقكلمنهوىيًٌٍَُِّْﻗﻛﻟﻵﻷﻹﻻﻣﻧﻬﻩ�"
+  },
+  "ibm1046": "cp1046",
+  "csibm1046": "cp1046",
+  "cp1124": {
+    "type": "_sbcs",
+    "chars": " ЁЂҐЄЅІЇЈЉЊЋЌЎЏАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя№ёђґєѕіїјљњћќ§ўџ"
+  },
+  "ibm1124": "cp1124",
+  "csibm1124": "cp1124",
+  "cp1125": {
+    "type": "_sbcs",
+    "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмноп░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀рстуфхцчшщъыьэюяЁёҐґЄєІіЇї·√№¤■ "
+  },
+  "ibm1125": "cp1125",
+  "csibm1125": "cp1125",
+  "cp1129": {
+    "type": "_sbcs",
+    "chars": " ¡¢£¤¥¦§œ©ª«¬®¯°±²³Ÿµ¶·Œ¹º»¼½¾¿ÀÁÂĂÄÅÆÇÈÉÊË̀ÍÎÏĐÑ̉ÓÔƠÖ×ØÙÚÛÜỮßàáâăäåæçèéêë́íîïđṇ̃óôơö÷øùúûüư₫ÿ"
+  },
+  "ibm1129": "cp1129",
+  "csibm1129": "cp1129",
+  "cp1133": {
+    "type": "_sbcs",
+    "chars": " ກຂຄງຈສຊຍດຕຖທນບປຜຝພຟມຢຣລວຫອຮ���ຯະາຳິີຶືຸູຼັົຽ���ເແໂໃໄ່້໊໋໌ໍໆ�ໜໝ₭����������������໐໑໒໓໔໕໖໗໘໙��¢¬¦�"
+  },
+  "ibm1133": "cp1133",
+  "csibm1133": "cp1133",
+  "cp1161": {
+    "type": "_sbcs",
+    "chars": "��������������������������������่กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู้๊๋€฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛¢¬¦ "
+  },
+  "ibm1161": "cp1161",
+  "csibm1161": "cp1161",
+  "cp1162": {
+    "type": "_sbcs",
+    "chars": "€…‘’“”•–— กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู����฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛����"
+  },
+  "ibm1162": "cp1162",
+  "csibm1162": "cp1162",
+  "cp1163": {
+    "type": "_sbcs",
+    "chars": " ¡¢£€¥¦§œ©ª«¬®¯°±²³Ÿµ¶·Œ¹º»¼½¾¿ÀÁÂĂÄÅÆÇÈÉÊË̀ÍÎÏĐÑ̉ÓÔƠÖ×ØÙÚÛÜỮßàáâăäåæçèéêë́íîïđṇ̃óôơö÷øùúûüư₫ÿ"
+  },
+  "ibm1163": "cp1163",
+  "csibm1163": "cp1163",
+  "maccroatian": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®Š™´¨≠ŽØ∞±≤≥∆µ∂∑∏š∫ªºΩžø¿¡¬√ƒ≈Ć«Č… ÀÃÕŒœĐ—“”‘’÷◊�©⁄¤‹›Æ»–·‚„‰ÂćÁčÈÍÎÏÌÓÔđÒÚÛÙıˆ˜¯πË˚¸Êæˇ"
+  },
+  "maccyrillic": {
+    "type": "_sbcs",
+    "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ†°¢£§•¶І®©™Ђђ≠Ѓѓ∞±≤≥іµ∂ЈЄєЇїЉљЊњјЅ¬√ƒ≈∆«»… ЋћЌќѕ–—“”‘’÷„ЎўЏџ№Ёёяабвгдежзийклмнопрстуфхцчшщъыьэю¤"
+  },
+  "macgreek": {
+    "type": "_sbcs",
+    "chars": "Ä¹²É³ÖÜ΅àâä΄¨çéèêë£™îï•½‰ôö¦ùûü†ΓΔΘΛΞΠß®©ΣΪ§≠°·Α±≤≥¥ΒΕΖΗΙΚΜΦΫΨΩάΝ¬ΟΡ≈Τ«»… ΥΧΆΈœ–―“”‘’÷ΉΊΌΎέήίόΏύαβψδεφγηιξκλμνοπώρστθωςχυζϊϋΐΰ�"
+  },
+  "maciceland": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûüÝ°¢£§•¶ß®©™´¨≠ÆØ∞±≤≥¥µ∂∑∏π∫ªºΩæø¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸ⁄¤ÐðÞþý·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙıˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "macroman": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®©™´¨≠ÆØ∞±≤≥¥µ∂∑∏π∫ªºΩæø¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸ⁄¤‹›ﬁﬂ‡·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙıˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "macromania": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®©™´¨≠ĂŞ∞±≤≥¥µ∂∑∏π∫ªºΩăş¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸ⁄¤‹›Ţţ‡·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙıˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "macthai": {
+    "type": "_sbcs",
+    "chars": "«»…“”�•‘’� กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู–—฿เแโใไๅๆ็่้๊๋์ํ™๏๐๑๒๓๔๕๖๗๘๙®©����"
+  },
+  "macturkish": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®©™´¨≠ÆØ∞±≤≥¥µ∂∑∏π∫ªºΩæø¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸĞğİıŞş‡·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙ�ˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "macukraine": {
+    "type": "_sbcs",
+    "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ†°Ґ£§•¶І®©™Ђђ≠Ѓѓ∞±≤≥іµґЈЄєЇїЉљЊњјЅ¬√ƒ≈∆«»… ЋћЌќѕ–—“”‘’÷„ЎўЏџ№Ёёяабвгдежзийклмнопрстуфхцчшщъыьэю¤"
+  },
+  "koi8r": {
+    "type": "_sbcs",
+    "chars": "─│┌┐└┘├┤┬┴┼▀▄█▌▐░▒▓⌠■∙√≈≤≥ ⌡°²·÷═║╒ё╓╔╕╖╗╘╙╚╛╜╝╞╟╠╡Ё╢╣╤╥╦╧╨╩╪╫╬©юабцдефгхийклмнопярстужвьызшэщчъЮАБЦДЕФГХИЙКЛМНОПЯРСТУЖВЬЫЗШЭЩЧЪ"
+  },
+  "koi8u": {
+    "type": "_sbcs",
+    "chars": "─│┌┐└┘├┤┬┴┼▀▄█▌▐░▒▓⌠■∙√≈≤≥ ⌡°²·÷═║╒ёє╔ії╗╘╙╚╛ґ╝╞╟╠╡ЁЄ╣ІЇ╦╧╨╩╪Ґ╬©юабцдефгхийклмнопярстужвьызшэщчъЮАБЦДЕФГХИЙКЛМНОПЯРСТУЖВЬЫЗШЭЩЧЪ"
+  },
+  "koi8ru": {
+    "type": "_sbcs",
+    "chars": "─│┌┐└┘├┤┬┴┼▀▄█▌▐░▒▓⌠■∙√≈≤≥ ⌡°²·÷═║╒ёє╔ії╗╘╙╚╛ґў╞╟╠╡ЁЄ╣ІЇ╦╧╨╩╪ҐЎ©юабцдефгхийклмнопярстужвьызшэщчъЮАБЦДЕФГХИЙКЛМНОПЯРСТУЖВЬЫЗШЭЩЧЪ"
+  },
+  "koi8t": {
+    "type": "_sbcs",
+    "chars": "қғ‚Ғ„…†‡�‰ҳ‹ҲҷҶ�Қ‘’“”•–—�™�›�����ӯӮё¤ӣ¦§���«¬®�°±²Ё�Ӣ¶·�№�»���©юабцдефгхийклмнопярстужвьызшэщчъЮАБЦДЕФГХИЙКЛМНОПЯРСТУЖВЬЫЗШЭЩЧЪ"
+  },
+  "armscii8": {
+    "type": "_sbcs",
+    "chars": " �և։)(»«—.՝,-֊…՜՛՞ԱաԲբԳգԴդԵեԶզԷէԸըԹթԺժԻիԼլԽխԾծԿկՀհՁձՂղՃճՄմՅյՆնՇշՈոՉչՊպՋջՌռՍսՎվՏտՐրՑցՒւՓփՔքՕօՖֆ՚�"
+  },
+  "rk1048": {
+    "type": "_sbcs",
+    "chars": "ЂЃ‚ѓ„…†‡€‰Љ‹ЊҚҺЏђ‘’“”•–—�™љ›њқһџ ҰұӘ¤Ө¦§Ё©Ғ«¬®Ү°±Ііөµ¶·ё№ғ»әҢңүАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя"
+  },
+  "tcvn": {
+    "type": "_sbcs",
+    "chars": "\u0000ÚỤ\u0003ỪỬỮ\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010ỨỰỲỶỸÝỴ\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~ÀẢÃÁẠẶẬÈẺẼÉẸỆÌỈĨÍỊÒỎÕÓỌỘỜỞỠỚỢÙỦŨ ĂÂÊÔƠƯĐăâêôơưđẶ̀̀̉̃́àảãáạẲằẳẵắẴẮẦẨẪẤỀặầẩẫấậèỂẻẽéẹềểễếệìỉỄẾỒĩíịòỔỏõóọồổỗốộờởỡớợùỖủũúụừửữứựỳỷỹýỵỐ"
+  },
+  "georgianacademy": {
+    "type": "_sbcs",
+    "chars": "‚ƒ„…†‡ˆ‰Š‹Œ‘’“”•–—˜™š›œŸ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿აბგდევზთიკლმნოპჟრსტუფქღყშჩცძწჭხჯჰჱჲჳჴჵჶçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "georgianps": {
+    "type": "_sbcs",
+    "chars": "‚ƒ„…†‡ˆ‰Š‹Œ‘’“”•–—˜™š›œŸ ¡¢£¤¥¦§¨©ª«¬®¯°±²³´µ¶·¸¹º»¼½¾¿აბგდევზჱთიკლმნჲოპჟრსტჳუფქღყშჩცძწჭხჴჯჰჵæçèéêëìíîïðñòóôõö÷øùúûüýþÿ"
+  },
+  "pt154": {
+    "type": "_sbcs",
+    "chars": "ҖҒӮғ„…ҶҮҲүҠӢҢҚҺҸҗ‘’“”•–—ҳҷҡӣңқһҹ ЎўЈӨҘҰ§Ё©Ә«¬ӯ®Ҝ°ұІіҙө¶·ё№ә»јҪҫҝАБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя"
+  },
+  "viscii": {
+    "type": "_sbcs",
+    "chars": "\u0000\u0001Ẳ\u0003\u0004ẴẪ\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010\u0011\u0012\u0013Ỷ\u0015\u0016\u0017\u0018Ỹ\u001a\u001b\u001c\u001dỴ\u001f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~ẠẮẰẶẤẦẨẬẼẸẾỀỂỄỆỐỒỔỖỘỢỚỜỞỊỎỌỈỦŨỤỲÕắằặấầẩậẽẹếềểễệốồổỗỠƠộờởịỰỨỪỬơớƯÀÁÂÃẢĂẳẵÈÉÊẺÌÍĨỳĐứÒÓÔạỷừửÙÚỹỵÝỡưàáâãảăữẫèéêẻìíĩỉđựòóôõỏọụùúũủýợỮ"
+  },
+  "iso646cn": {
+    "type": "_sbcs",
+    "chars": "\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f !\"#¥%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}‾��������������������������������������������������������������������������������������������������������������������������������"
+  },
+  "iso646jp": {
+    "type": "_sbcs",
+    "chars": "\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007\b\t\n\u000b\f\r\u000e\u000f\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[¥]^_`abcdefghijklmnopqrstuvwxyz{|}‾��������������������������������������������������������������������������������������������������������������������������������"
+  },
+  "hproman8": {
+    "type": "_sbcs",
+    "chars": " ÀÂÈÊËÎÏ´ˋˆ¨˜ÙÛ₤¯Ýý°ÇçÑñ¡¿¤£¥§ƒ¢âêôûáéóúàèòùäëöüÅîØÆåíøæÄìÖÜÉïßÔÁÃãÐðÍÌÓÒÕõŠšÚŸÿÞþ·µ¶¾—¼½ªº«■»±�"
+  },
+  "macintosh": {
+    "type": "_sbcs",
+    "chars": "ÄÅÇÉÑÖÜáàâäãåçéèêëíìîïñóòôöõúùûü†°¢£§•¶ß®©™´¨≠ÆØ∞±≤≥¥µ∂∑∏π∫ªºΩæø¿¡¬√ƒ≈∆«»… ÀÃÕŒœ–—“”‘’÷◊ÿŸ⁄¤‹›ﬁﬂ‡·‚„‰ÂÊÁËÈÍÎÏÌÓÔ�ÒÚÛÙıˆ˜¯˘˙˚¸˝˛ˇ"
+  },
+  "ascii": {
+    "type": "_sbcs",
+    "chars": "��������������������������������������������������������������������������������������������������������������������������������"
+  },
+  "tis620": {
+    "type": "_sbcs",
+    "chars": "���������������������������������กขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะัาำิีึืฺุู����฿เแโใไๅๆ็่้๊๋์ํ๎๏๐๑๒๓๔๕๖๗๘๙๚๛����"
+  }
+}
\ No newline at end of file
diff --git a/server/node_modules/iconv-lite/encodings/sbcs-data.js b/server/node_modules/iconv-lite/encodings/sbcs-data.js
new file mode 100644
index 0000000..fdb81a3
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/sbcs-data.js
@@ -0,0 +1,174 @@
+"use strict";
+
+// Manually added data to be used by sbcs codec in addition to generated one.
+
+module.exports = {
+    // Not supported by iconv, not sure why.
+    "10029": "maccenteuro",
+    "maccenteuro": {
+        "type": "_sbcs",
+        "chars": "ÄĀāÉĄÖÜáąČäčĆćéŹźĎíďĒēĖóėôöõúĚěü†°Ę£§•¶ß®©™ę¨≠ģĮįĪ≤≥īĶ∂∑łĻļĽľĹĺŅņŃ¬√ńŇ∆«»… ňŐÕőŌ–—“”‘’÷◊ōŔŕŘ‹›řŖŗŠ‚„šŚśÁŤťÍŽžŪÓÔūŮÚůŰűŲųÝýķŻŁżĢˇ"
+    },
+
+    "808": "cp808",
+    "ibm808": "cp808",
+    "cp808": {
+        "type": "_sbcs",
+        "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмноп░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀рстуфхцчшщъыьэюяЁёЄєЇїЎў°∙·√№€■ "
+    },
+
+    "mik": {
+        "type": "_sbcs",
+        "chars": "АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдежзийклмнопрстуфхцчшщъыьэюя└┴┬├─┼╣║╚╔╩╦╠═╬┐░▒▓│┤№§╗╝┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ "
+    },
+
+    // Aliases of generated encodings.
+    "ascii8bit": "ascii",
+    "usascii": "ascii",
+    "ansix34": "ascii",
+    "ansix341968": "ascii",
+    "ansix341986": "ascii",
+    "csascii": "ascii",
+    "cp367": "ascii",
+    "ibm367": "ascii",
+    "isoir6": "ascii",
+    "iso646us": "ascii",
+    "iso646irv": "ascii",
+    "us": "ascii",
+
+    "latin1": "iso88591",
+    "latin2": "iso88592",
+    "latin3": "iso88593",
+    "latin4": "iso88594",
+    "latin5": "iso88599",
+    "latin6": "iso885910",
+    "latin7": "iso885913",
+    "latin8": "iso885914",
+    "latin9": "iso885915",
+    "latin10": "iso885916",
+
+    "csisolatin1": "iso88591",
+    "csisolatin2": "iso88592",
+    "csisolatin3": "iso88593",
+    "csisolatin4": "iso88594",
+    "csisolatincyrillic": "iso88595",
+    "csisolatinarabic": "iso88596",
+    "csisolatingreek" : "iso88597",
+    "csisolatinhebrew": "iso88598",
+    "csisolatin5": "iso88599",
+    "csisolatin6": "iso885910",
+
+    "l1": "iso88591",
+    "l2": "iso88592",
+    "l3": "iso88593",
+    "l4": "iso88594",
+    "l5": "iso88599",
+    "l6": "iso885910",
+    "l7": "iso885913",
+    "l8": "iso885914",
+    "l9": "iso885915",
+    "l10": "iso885916",
+
+    "isoir14": "iso646jp",
+    "isoir57": "iso646cn",
+    "isoir100": "iso88591",
+    "isoir101": "iso88592",
+    "isoir109": "iso88593",
+    "isoir110": "iso88594",
+    "isoir144": "iso88595",
+    "isoir127": "iso88596",
+    "isoir126": "iso88597",
+    "isoir138": "iso88598",
+    "isoir148": "iso88599",
+    "isoir157": "iso885910",
+    "isoir166": "tis620",
+    "isoir179": "iso885913",
+    "isoir199": "iso885914",
+    "isoir203": "iso885915",
+    "isoir226": "iso885916",
+
+    "cp819": "iso88591",
+    "ibm819": "iso88591",
+
+    "cyrillic": "iso88595",
+
+    "arabic": "iso88596",
+    "arabic8": "iso88596",
+    "ecma114": "iso88596",
+    "asmo708": "iso88596",
+
+    "greek" : "iso88597",
+    "greek8" : "iso88597",
+    "ecma118" : "iso88597",
+    "elot928" : "iso88597",
+
+    "hebrew": "iso88598",
+    "hebrew8": "iso88598",
+
+    "turkish": "iso88599",
+    "turkish8": "iso88599",
+
+    "thai": "iso885911",
+    "thai8": "iso885911",
+
+    "celtic": "iso885914",
+    "celtic8": "iso885914",
+    "isoceltic": "iso885914",
+
+    "tis6200": "tis620",
+    "tis62025291": "tis620",
+    "tis62025330": "tis620",
+
+    "10000": "macroman",
+    "10006": "macgreek",
+    "10007": "maccyrillic",
+    "10079": "maciceland",
+    "10081": "macturkish",
+
+    "cspc8codepage437": "cp437",
+    "cspc775baltic": "cp775",
+    "cspc850multilingual": "cp850",
+    "cspcp852": "cp852",
+    "cspc862latinhebrew": "cp862",
+    "cpgr": "cp869",
+
+    "msee": "cp1250",
+    "mscyrl": "cp1251",
+    "msansi": "cp1252",
+    "msgreek": "cp1253",
+    "msturk": "cp1254",
+    "mshebr": "cp1255",
+    "msarab": "cp1256",
+    "winbaltrim": "cp1257",
+
+    "cp20866": "koi8r",
+    "20866": "koi8r",
+    "ibm878": "koi8r",
+    "cskoi8r": "koi8r",
+
+    "cp21866": "koi8u",
+    "21866": "koi8u",
+    "ibm1168": "koi8u",
+
+    "strk10482002": "rk1048",
+
+    "tcvn5712": "tcvn",
+    "tcvn57121": "tcvn",
+
+    "gb198880": "iso646cn",
+    "cn": "iso646cn",
+
+    "csiso14jisc6220ro": "iso646jp",
+    "jisc62201969ro": "iso646jp",
+    "jp": "iso646jp",
+
+    "cshproman8": "hproman8",
+    "r8": "hproman8",
+    "roman8": "hproman8",
+    "xroman8": "hproman8",
+    "ibm1051": "hproman8",
+
+    "mac": "macintosh",
+    "csmacintosh": "macintosh",
+};
+
diff --git a/server/node_modules/iconv-lite/encodings/tables/big5-added.json b/server/node_modules/iconv-lite/encodings/tables/big5-added.json
new file mode 100644
index 0000000..3c3d3c2
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/tables/big5-added.json
@@ -0,0 +1,122 @@
+[
+["8740","䏰䰲䘃䖦䕸𧉧䵷䖳𧲱䳢𧳅㮕䜶䝄䱇䱀𤊿𣘗𧍒𦺋𧃒䱗𪍑䝏䗚䲅𧱬䴇䪤䚡𦬣爥𥩔𡩣𣸆𣽡晍囻"],
+["8767","綕夝𨮹㷴霴𧯯寛𡵞媤㘥𩺰嫑宷峼杮薓𩥅瑡璝㡵𡵓𣚞𦀡㻬"],
+["87a1","𥣞㫵竼龗𤅡𨤍𣇪𠪊𣉞䌊蒄龖鐯䤰蘓墖靊鈘秐稲晠権袝瑌篅枂稬剏遆㓦珄𥶹瓆鿇垳䤯呌䄱𣚎堘穲𧭥讏䚮𦺈䆁𥶙箮𢒼鿈𢓁𢓉𢓌鿉蔄𣖻䂴鿊䓡𪷿拁灮鿋"],
+["8840","㇀",4,"𠄌㇅𠃑𠃍㇆㇇𠃋𡿨㇈𠃊㇉㇊㇋㇌𠄎㇍㇎ĀÁǍÀĒÉĚÈŌÓǑÒ࿿Ê̄Ế࿿Ê̌ỀÊāáǎàɑēéěèīíǐìōóǒòūúǔùǖǘǚ"],
+["88a1","ǜü࿿ê̄ế࿿ê̌ềêɡ⏚⏛"],
+["8940","𪎩𡅅"],
+["8943","攊"],
+["8946","丽滝鵎釟"],
+["894c","𧜵撑会伨侨兖兴农凤务动医华发变团声处备夲头学实実岚庆总斉柾栄桥济炼电纤纬纺织经统缆缷艺苏药视设询车轧轮"],
+["89a1","琑糼緍楆竉刧"],
+["89ab","醌碸酞肼"],
+["89b0","贋胶𠧧"],
+["89b5","肟黇䳍鷉鸌䰾𩷶𧀎鸊𪄳㗁"],
+["89c1","溚舾甙"],
+["89c5","䤑马骏龙禇𨑬𡷊𠗐𢫦两亁亀亇亿仫伷㑌侽㹈倃傈㑽㒓㒥円夅凛凼刅争剹劐匧㗇厩㕑厰㕓参吣㕭㕲㚁咓咣咴咹哐哯唘唣唨㖘唿㖥㖿嗗㗅"],
+["8a40","𧶄唥"],
+["8a43","𠱂𠴕𥄫喐𢳆㧬𠍁蹆𤶸𩓥䁓𨂾睺𢰸㨴䟕𨅝𦧲𤷪擝𠵼𠾴𠳕𡃴撍蹾𠺖𠰋𠽤𢲩𨉖𤓓"],
+["8a64","𠵆𩩍𨃩䟴𤺧𢳂骲㩧𩗴㿭㔆𥋇𩟔𧣈𢵄鵮頕"],
+["8a76","䏙𦂥撴哣𢵌𢯊𡁷㧻𡁯"],
+["8aa1","𦛚𦜖𧦠擪𥁒𠱃蹨𢆡𨭌𠜱"],
+["8aac","䠋𠆩㿺塳𢶍"],
+["8ab2","𤗈𠓼𦂗𠽌𠶖啹䂻䎺"],
+["8abb","䪴𢩦𡂝膪飵𠶜捹㧾𢝵跀嚡摼㹃"],
+["8ac9","𪘁𠸉𢫏𢳉"],
+["8ace","𡃈𣧂㦒㨆𨊛㕸𥹉𢃇噒𠼱𢲲𩜠㒼氽𤸻"],
+["8adf","𧕴𢺋𢈈𪙛𨳍𠹺𠰴𦠜羓𡃏𢠃𢤹㗻𥇣𠺌𠾍𠺪㾓𠼰𠵇𡅏𠹌"],
+["8af6","𠺫𠮩𠵈𡃀𡄽㿹𢚖搲𠾭"],
+["8b40","𣏴𧘹𢯎𠵾𠵿𢱑𢱕㨘𠺘𡃇𠼮𪘲𦭐𨳒𨶙𨳊閪哌苄喹"],
+["8b55","𩻃鰦骶𧝞𢷮煀腭胬尜𦕲脴㞗卟𨂽醶𠻺𠸏𠹷𠻻㗝𤷫㘉𠳖嚯𢞵𡃉𠸐𠹸𡁸𡅈𨈇𡑕𠹹𤹐𢶤婔𡀝𡀞𡃵𡃶垜𠸑"],
+["8ba1","𧚔𨋍𠾵𠹻𥅾㜃𠾶𡆀𥋘𪊽𤧚𡠺𤅷𨉼墙剨㘚𥜽箲孨䠀䬬鼧䧧鰟鮍𥭴𣄽嗻㗲嚉丨夂𡯁屮靑𠂆乛亻㔾尣彑忄㣺扌攵歺氵氺灬爫丬犭𤣩罒礻糹罓𦉪㓁"],
+["8bde","𦍋耂肀𦘒𦥑卝衤见𧢲讠贝钅镸长门𨸏韦页风飞饣𩠐鱼鸟黄歯龜丷𠂇阝户钢"],
+["8c40","倻淾𩱳龦㷉袏𤅎灷峵䬠𥇍㕙𥴰愢𨨲辧釶熑朙玺𣊁𪄇㲋𡦀䬐磤琂冮𨜏䀉橣𪊺䈣蘏𠩯稪𩥇𨫪靕灍匤𢁾鏴盙𨧣龧矝亣俰傼丯众龨吴綋墒壐𡶶庒庙忂𢜒斋"],
+["8ca1","𣏹椙橃𣱣泿"],
+["8ca7","爀𤔅玌㻛𤨓嬕璹讃𥲤𥚕窓篬糃繬苸薗龩袐龪躹龫迏蕟駠鈡龬𨶹𡐿䁱䊢娚"],
+["8cc9","顨杫䉶圽"],
+["8cce","藖𤥻芿𧄍䲁𦵴嵻𦬕𦾾龭龮宖龯曧繛湗秊㶈䓃𣉖𢞖䎚䔶"],
+["8ce6","峕𣬚諹屸㴒𣕑嵸龲煗䕘𤃬𡸣䱷㥸㑊𠆤𦱁諌侴𠈹妿腬顖𩣺弻"],
+["8d40","𠮟"],
+["8d42","𢇁𨥭䄂䚻𩁹㼇龳𪆵䃸㟖䛷𦱆䅼𨚲𧏿䕭㣔𥒚䕡䔛䶉䱻䵶䗪㿈𤬏㙡䓞䒽䇭崾嵈嵖㷼㠏嶤嶹㠠㠸幂庽弥徃㤈㤔㤿㥍惗愽峥㦉憷憹懏㦸戬抐拥挘㧸嚱"],
+["8da1","㨃揢揻搇摚㩋擀崕嘡龟㪗斆㪽旿晓㫲暒㬢朖㭂枤栀㭘桊梄㭲㭱㭻椉楃牜楤榟榅㮼槖㯝橥橴橱檂㯬檙㯲檫檵櫔櫶殁毁毪汵沪㳋洂洆洦涁㳯涤涱渕渘温溆𨧀溻滢滚齿滨滩漤漴㵆𣽁澁澾㵪㵵熷岙㶊瀬㶑灐灔灯灿炉𠌥䏁㗱𠻘"],
+["8e40","𣻗垾𦻓焾𥟠㙎榢𨯩孴穉𥣡𩓙穥穽𥦬窻窰竂竃燑𦒍䇊竚竝竪䇯咲𥰁笋筕笩𥌎𥳾箢筯莜𥮴𦱿篐萡箒箸𥴠㶭𥱥蒒篺簆簵𥳁籄粃𤢂粦晽𤕸糉糇糦籴糳糵糎"],
+["8ea1","繧䔝𦹄絝𦻖璍綉綫焵綳緒𤁗𦀩緤㴓緵𡟹緥𨍭縝𦄡𦅚繮纒䌫鑬縧罀罁罇礶𦋐駡羗𦍑羣𡙡𠁨䕜𣝦䔃𨌺翺𦒉者耈耝耨耯𪂇𦳃耻耼聡𢜔䦉𦘦𣷣𦛨朥肧𨩈脇脚墰𢛶汿𦒘𤾸擧𡒊舘𡡞橓𤩥𤪕䑺舩𠬍𦩒𣵾俹𡓽蓢荢𦬊𤦧𣔰𡝳𣷸芪椛芳䇛"],
+["8f40","蕋苐茚𠸖𡞴㛁𣅽𣕚艻苢茘𣺋𦶣𦬅𦮗𣗎㶿茝嗬莅䔋𦶥莬菁菓㑾𦻔橗蕚㒖𦹂𢻯葘𥯤葱㷓䓤檧葊𣲵祘蒨𦮖𦹷𦹃蓞萏莑䒠蒓蓤𥲑䉀𥳀䕃蔴嫲𦺙䔧蕳䔖枿蘖"],
+["8fa1","𨘥𨘻藁𧂈蘂𡖂𧃍䕫䕪蘨㙈𡢢号𧎚虾蝱𪃸蟮𢰧螱蟚蠏噡虬桖䘏衅衆𧗠𣶹𧗤衞袜䙛袴袵揁装睷𧜏覇覊覦覩覧覼𨨥觧𧤤𧪽誜瞓釾誐𧩙竩𧬺𣾏䜓𧬸煼謌謟𥐰𥕥謿譌譍誩𤩺讐讛誯𡛟䘕衏貛𧵔𧶏貫㜥𧵓賖𧶘𧶽贒贃𡤐賛灜贑𤳉㻐起"],
+["9040","趩𨀂𡀔𤦊㭼𨆼𧄌竧躭躶軃鋔輙輭𨍥𨐒辥錃𪊟𠩐辳䤪𨧞𨔽𣶻廸𣉢迹𪀔𨚼𨔁𢌥㦀𦻗逷𨔼𧪾遡𨕬𨘋邨𨜓郄𨛦邮都酧㫰醩釄粬𨤳𡺉鈎沟鉁鉢𥖹銹𨫆𣲛𨬌𥗛"],
+["90a1","𠴱錬鍫𨫡𨯫炏嫃𨫢𨫥䥥鉄𨯬𨰹𨯿鍳鑛躼閅閦鐦閠濶䊹𢙺𨛘𡉼𣸮䧟氜陻隖䅬隣𦻕懚隶磵𨫠隽双䦡𦲸𠉴𦐐𩂯𩃥𤫑𡤕𣌊霱虂霶䨏䔽䖅𤫩灵孁霛靜𩇕靗孊𩇫靟鐥僐𣂷𣂼鞉鞟鞱鞾韀韒韠𥑬韮琜𩐳響韵𩐝𧥺䫑頴頳顋顦㬎𧅵㵑𠘰𤅜"],
+["9140","𥜆飊颷飈飇䫿𦴧𡛓喰飡飦飬鍸餹𤨩䭲𩡗𩤅駵騌騻騐驘𥜥㛄𩂱𩯕髠髢𩬅髴䰎鬔鬭𨘀倴鬴𦦨㣃𣁽魐魀𩴾婅𡡣鮎𤉋鰂鯿鰌𩹨鷔𩾷𪆒𪆫𪃡𪄣𪇟鵾鶃𪄴鸎梈"],
+["91a1","鷄𢅛𪆓𪈠𡤻𪈳鴹𪂹𪊴麐麕麞麢䴴麪麯𤍤黁㭠㧥㴝伲㞾𨰫鼂鼈䮖鐤𦶢鼗鼖鼹嚟嚊齅馸𩂋韲葿齢齩竜龎爖䮾𤥵𤦻煷𤧸𤍈𤩑玞𨯚𡣺禟𨥾𨸶鍩鏳𨩄鋬鎁鏋𨥬𤒹爗㻫睲穃烐𤑳𤏸煾𡟯炣𡢾𣖙㻇𡢅𥐯𡟸㜢𡛻𡠹㛡𡝴𡣑𥽋㜣𡛀坛𤨥𡏾𡊨"],
+["9240","𡏆𡒶蔃𣚦蔃葕𤦔𧅥𣸱𥕜𣻻𧁒䓴𣛮𩦝𦼦柹㜳㰕㷧塬𡤢栐䁗𣜿𤃡𤂋𤄏𦰡哋嚞𦚱嚒𠿟𠮨𠸍鏆𨬓鎜仸儫㠙𤐶亼𠑥𠍿佋侊𥙑婨𠆫𠏋㦙𠌊𠐔㐵伩𠋀𨺳𠉵諚𠈌亘"],
+["92a1","働儍侢伃𤨎𣺊佂倮偬傁俌俥偘僼兙兛兝兞湶𣖕𣸹𣺿浲𡢄𣺉冨凃𠗠䓝𠒣𠒒𠒑赺𨪜𠜎剙劤𠡳勡鍮䙺熌𤎌𠰠𤦬𡃤槑𠸝瑹㻞璙琔瑖玘䮎𤪼𤂍叐㖄爏𤃉喴𠍅响𠯆圝鉝雴鍦埝垍坿㘾壋媙𨩆𡛺𡝯𡜐娬妸銏婾嫏娒𥥆𡧳𡡡𤊕㛵洅瑃娡𥺃"],
+["9340","媁𨯗𠐓鏠璌𡌃焅䥲鐈𨧻鎽㞠尞岞幞幈𡦖𡥼𣫮廍孏𡤃𡤄㜁𡢠㛝𡛾㛓脪𨩇𡶺𣑲𨦨弌弎𡤧𡞫婫𡜻孄蘔𧗽衠恾𢡠𢘫忛㺸𢖯𢖾𩂈𦽳懀𠀾𠁆𢘛憙憘恵𢲛𢴇𤛔𩅍"],
+["93a1","摱𤙥𢭪㨩𢬢𣑐𩣪𢹸挷𪑛撶挱揑𤧣𢵧护𢲡搻敫楲㯴𣂎𣊭𤦉𣊫唍𣋠𡣙𩐿曎𣊉𣆳㫠䆐𥖄𨬢𥖏𡛼𥕛𥐥磮𣄃𡠪𣈴㑤𣈏𣆂𤋉暎𦴤晫䮓昰𧡰𡷫晣𣋒𣋡昞𥡲㣑𣠺𣞼㮙𣞢𣏾瓐㮖枏𤘪梶栞㯄檾㡣𣟕𤒇樳橒櫉欅𡤒攑梘橌㯗橺歗𣿀𣲚鎠鋲𨯪𨫋"],
+["9440","銉𨀞𨧜鑧涥漋𤧬浧𣽿㶏渄𤀼娽渊塇洤硂焻𤌚𤉶烱牐犇犔𤞏𤜥兹𤪤𠗫瑺𣻸𣙟𤩊𤤗𥿡㼆㺱𤫟𨰣𣼵悧㻳瓌琼鎇琷䒟𦷪䕑疃㽣𤳙𤴆㽘畕癳𪗆㬙瑨𨫌𤦫𤦎㫻"],
+["94a1","㷍𤩎㻿𤧅𤣳釺圲鍂𨫣𡡤僟𥈡𥇧睸𣈲眎眏睻𤚗𣞁㩞𤣰琸璛㺿𤪺𤫇䃈𤪖𦆮錇𥖁砞碍碈磒珐祙𧝁𥛣䄎禛蒖禥樭𣻺稺秴䅮𡛦䄲鈵秱𠵌𤦌𠊙𣶺𡝮㖗啫㕰㚪𠇔𠰍竢婙𢛵𥪯𥪜娍𠉛磰娪𥯆竾䇹籝籭䈑𥮳𥺼𥺦糍𤧹𡞰粎籼粮檲緜縇緓罎𦉡"],
+["9540","𦅜𧭈綗𥺂䉪𦭵𠤖柖𠁎𣗏埄𦐒𦏸𤥢翝笧𠠬𥫩𥵃笌𥸎駦虅驣樜𣐿㧢𤧷𦖭騟𦖠蒀𧄧𦳑䓪脷䐂胆脉腂𦞴飃𦩂艢艥𦩑葓𦶧蘐𧈛媆䅿𡡀嬫𡢡嫤𡣘蚠蜨𣶏蠭𧐢娂"],
+["95a1","衮佅袇袿裦襥襍𥚃襔𧞅𧞄𨯵𨯙𨮜𨧹㺭蒣䛵䛏㟲訽訜𩑈彍鈫𤊄旔焩烄𡡅鵭貟賩𧷜妚矃姰䍮㛔踪躧𤰉輰轊䋴汘澻𢌡䢛潹溋𡟚鯩㚵𤤯邻邗啱䤆醻鐄𨩋䁢𨫼鐧𨰝𨰻蓥訫閙閧閗閖𨴴瑅㻂𤣿𤩂𤏪㻧𣈥随𨻧𨹦𨹥㻌𤧭𤩸𣿮琒瑫㻼靁𩂰"],
+["9640","桇䨝𩂓𥟟靝鍨𨦉𨰦𨬯𦎾銺嬑譩䤼珹𤈛鞛靱餸𠼦巁𨯅𤪲頟𩓚鋶𩗗釥䓀𨭐𤩧𨭤飜𨩅㼀鈪䤥萔餻饍𧬆㷽馛䭯馪驜𨭥𥣈檏騡嫾騯𩣱䮐𩥈馼䮽䮗鍽塲𡌂堢𤦸"],
+["96a1","𡓨硄𢜟𣶸棅㵽鑘㤧慐𢞁𢥫愇鱏鱓鱻鰵鰐魿鯏𩸭鮟𪇵𪃾鴡䲮𤄄鸘䲰鴌𪆴𪃭𪃳𩤯鶥蒽𦸒𦿟𦮂藼䔳𦶤𦺄𦷰萠藮𦸀𣟗𦁤秢𣖜𣙀䤭𤧞㵢鏛銾鍈𠊿碹鉷鑍俤㑀遤𥕝砽硔碶硋𡝗𣇉𤥁㚚佲濚濙瀞瀞吔𤆵垻壳垊鴖埗焴㒯𤆬燫𦱀𤾗嬨𡞵𨩉"],
+["9740","愌嫎娋䊼𤒈㜬䭻𨧼鎻鎸𡣖𠼝葲𦳀𡐓𤋺𢰦𤏁妔𣶷𦝁綨𦅛𦂤𤦹𤦋𨧺鋥珢㻩璴𨭣𡢟㻡𤪳櫘珳珻㻖𤨾𤪔𡟙𤩦𠎧𡐤𤧥瑈𤤖炥𤥶銄珦鍟𠓾錱𨫎𨨖鎆𨯧𥗕䤵𨪂煫"],
+["97a1","𤥃𠳿嚤𠘚𠯫𠲸唂秄𡟺緾𡛂𤩐𡡒䔮鐁㜊𨫀𤦭妰𡢿𡢃𧒄媡㛢𣵛㚰鉟婹𨪁𡡢鍴㳍𠪴䪖㦊僴㵩㵌𡎜煵䋻𨈘渏𩃤䓫浗𧹏灧沯㳖𣿭𣸭渂漌㵯𠏵畑㚼㓈䚀㻚䡱姄鉮䤾轁𨰜𦯀堒埈㛖𡑒烾𤍢𤩱𢿣𡊰𢎽梹楧𡎘𣓥𧯴𣛟𨪃𣟖𣏺𤲟樚𣚭𦲷萾䓟䓎"],
+["9840","𦴦𦵑𦲂𦿞漗𧄉茽𡜺菭𦲀𧁓𡟛妉媂𡞳婡婱𡤅𤇼㜭姯𡜼㛇熎鎐暚𤊥婮娫𤊓樫𣻹𧜶𤑛𤋊焝𤉙𨧡侰𦴨峂𤓎𧹍𤎽樌𤉖𡌄炦焳𤏩㶥泟勇𤩏繥姫崯㷳彜𤩝𡟟綤萦"],
+["98a1","咅𣫺𣌀𠈔坾𠣕𠘙㿥𡾞𪊶瀃𩅛嵰玏糓𨩙𩐠俈翧狍猐𧫴猸猹𥛶獁獈㺩𧬘遬燵𤣲珡臶㻊県㻑沢国琙琞琟㻢㻰㻴㻺瓓㼎㽓畂畭畲疍㽼痈痜㿀癍㿗癴㿜発𤽜熈嘣覀塩䀝睃䀹条䁅㗛瞘䁪䁯属瞾矋売砘点砜䂨砹硇硑硦葈𥔵礳栃礲䄃"],
+["9940","䄉禑禙辻稆込䅧窑䆲窼艹䇄竏竛䇏両筢筬筻簒簛䉠䉺类粜䊌粸䊔糭输烀𠳏総緔緐緽羮羴犟䎗耠耥笹耮耱联㷌垴炠肷胩䏭脌猪脎脒畠脔䐁㬹腖腙腚"],
+["99a1","䐓堺腼膄䐥膓䐭膥埯臁臤艔䒏芦艶苊苘苿䒰荗险榊萅烵葤惣蒈䔄蒾蓡蓸蔐蔸蕒䔻蕯蕰藠䕷虲蚒蚲蛯际螋䘆䘗袮裿褤襇覑𧥧訩訸誔誴豑賔賲贜䞘塟跃䟭仮踺嗘坔蹱嗵躰䠷軎転軤軭軲辷迁迊迌逳駄䢭飠鈓䤞鈨鉘鉫銱銮銿"],
+["9a40","鋣鋫鋳鋴鋽鍃鎄鎭䥅䥑麿鐗匁鐝鐭鐾䥪鑔鑹锭関䦧间阳䧥枠䨤靀䨵鞲韂噔䫤惨颹䬙飱塄餎餙冴餜餷饂饝饢䭰駅䮝騼鬏窃魩鮁鯝鯱鯴䱭鰠㝯𡯂鵉鰺"],
+["9aa1","黾噐鶓鶽鷀鷼银辶鹻麬麱麽黆铜黢黱黸竈齄𠂔𠊷𠎠椚铃妬𠓗塀铁㞹𠗕𠘕𠙶𡚺块煳𠫂𠫍𠮿呪吆𠯋咞𠯻𠰻𠱓𠱥𠱼惧𠲍噺𠲵𠳝𠳭𠵯𠶲𠷈楕鰯螥𠸄𠸎𠻗𠾐𠼭𠹳尠𠾼帋𡁜𡁏𡁶朞𡁻𡂈𡂖㙇𡂿𡃓𡄯𡄻卤蒭𡋣𡍵𡌶讁𡕷𡘙𡟃𡟇乸炻𡠭𡥪"],
+["9b40","𡨭𡩅𡰪𡱰𡲬𡻈拃𡻕𡼕熘桕𢁅槩㛈𢉼𢏗𢏺𢜪𢡱𢥏苽𢥧𢦓𢫕覥𢫨辠𢬎鞸𢬿顇骽𢱌"],
+["9b62","𢲈𢲷𥯨𢴈𢴒𢶷𢶕𢹂𢽴𢿌𣀳𣁦𣌟𣏞徱晈暿𧩹𣕧𣗳爁𤦺矗𣘚𣜖纇𠍆墵朎"],
+["9ba1","椘𣪧𧙗𥿢𣸑𣺹𧗾𢂚䣐䪸𤄙𨪚𤋮𤌍𤀻𤌴𤎖𤩅𠗊凒𠘑妟𡺨㮾𣳿𤐄𤓖垈𤙴㦛𤜯𨗨𩧉㝢𢇃譞𨭎駖𤠒𤣻𤨕爉𤫀𠱸奥𤺥𤾆𠝹軚𥀬劏圿煱𥊙𥐙𣽊𤪧喼𥑆𥑮𦭒釔㑳𥔿𧘲𥕞䜘𥕢𥕦𥟇𤤿𥡝偦㓻𣏌惞𥤃䝼𨥈𥪮𥮉𥰆𡶐垡煑澶𦄂𧰒遖𦆲𤾚譢𦐂𦑊"],
+["9c40","嵛𦯷輶𦒄𡤜諪𤧶𦒈𣿯𦔒䯀𦖿𦚵𢜛鑥𥟡憕娧晉侻嚹𤔡𦛼乪𤤴陖涏𦲽㘘襷𦞙𦡮𦐑𦡞營𦣇筂𩃀𠨑𦤦鄄𦤹穅鷰𦧺騦𦨭㙟𦑩𠀡禃𦨴𦭛崬𣔙菏𦮝䛐𦲤画补𦶮墶"],
+["9ca1","㜜𢖍𧁋𧇍㱔𧊀𧊅銁𢅺𧊋錰𧋦𤧐氹钟𧑐𠻸蠧裵𢤦𨑳𡞱溸𤨪𡠠㦤㚹尐秣䔿暶𩲭𩢤襃𧟌𧡘囖䃟𡘊㦡𣜯𨃨𡏅熭荦𧧝𩆨婧䲷𧂯𨦫𧧽𧨊𧬋𧵦𤅺筃祾𨀉澵𪋟樃𨌘厢𦸇鎿栶靝𨅯𨀣𦦵𡏭𣈯𨁈嶅𨰰𨂃圕頣𨥉嶫𤦈斾槕叒𤪥𣾁㰑朶𨂐𨃴𨄮𡾡𨅏"],
+["9d40","𨆉𨆯𨈚𨌆𨌯𨎊㗊𨑨𨚪䣺揦𨥖砈鉕𨦸䏲𨧧䏟𨧨𨭆𨯔姸𨰉輋𨿅𩃬筑𩄐𩄼㷷𩅞𤫊运犏嚋𩓧𩗩𩖰𩖸𩜲𩣑𩥉𩥪𩧃𩨨𩬎𩵚𩶛纟𩻸𩼣䲤镇𪊓熢𪋿䶑递𪗋䶜𠲜达嗁"],
+["9da1","辺𢒰边𤪓䔉繿潖檱仪㓤𨬬𧢝㜺躀𡟵𨀤𨭬𨮙𧨾𦚯㷫𧙕𣲷𥘵𥥖亚𥺁𦉘嚿𠹭踎孭𣺈𤲞揞拐𡟶𡡻攰嘭𥱊吚𥌑㷆𩶘䱽嘢嘞罉𥻘奵𣵀蝰东𠿪𠵉𣚺脗鵞贘瘻鱅癎瞹鍅吲腈苷嘥脲萘肽嗪祢噃吖𠺝㗎嘅嗱曱𨋢㘭甴嗰喺咗啲𠱁𠲖廐𥅈𠹶𢱢"],
+["9e40","𠺢麫絚嗞𡁵抝靭咔賍燶酶揼掹揾啩𢭃鱲𢺳冚㓟𠶧冧呍唞唓癦踭𦢊疱肶蠄螆裇膶萜𡃁䓬猄𤜆宐茋𦢓噻𢛴𧴯𤆣𧵳𦻐𧊶酰𡇙鈈𣳼𪚩𠺬𠻹牦𡲢䝎𤿂𧿹𠿫䃺"],
+["9ea1","鱝攟𢶠䣳𤟠𩵼𠿬𠸊恢𧖣𠿭"],
+["9ead","𦁈𡆇熣纎鵐业丄㕷嬍沲卧㚬㧜卽㚥𤘘墚𤭮舭呋垪𥪕𠥹"],
+["9ec5","㩒𢑥獴𩺬䴉鯭𣳾𩼰䱛𤾩𩖞𩿞葜𣶶𧊲𦞳𣜠挮紥𣻷𣸬㨪逈勌㹴㙺䗩𠒎癀嫰𠺶硺𧼮墧䂿噼鮋嵴癔𪐴麅䳡痹㟻愙𣃚𤏲"],
+["9ef5","噝𡊩垧𤥣𩸆刴𧂮㖭汊鵼"],
+["9f40","籖鬹埞𡝬屓擓𩓐𦌵𧅤蚭𠴨𦴢𤫢𠵱"],
+["9f4f","凾𡼏嶎霃𡷑麁遌笟鬂峑箣扨挵髿篏鬪籾鬮籂粆鰕篼鬉鼗鰛𤤾齚啳寃俽麘俲剠㸆勑坧偖妷帒韈鶫轜呩鞴饀鞺匬愰"],
+["9fa1","椬叚鰊鴂䰻陁榀傦畆𡝭駚剳"],
+["9fae","酙隁酜"],
+["9fb2","酑𨺗捿𦴣櫊嘑醎畺抅𠏼獏籰𥰡𣳽"],
+["9fc1","𤤙盖鮝个𠳔莾衂"],
+["9fc9","届槀僭坺刟巵从氱𠇲伹咜哚劚趂㗾弌㗳"],
+["9fdb","歒酼龥鮗頮颴骺麨麄煺笔"],
+["9fe7","毺蠘罸"],
+["9feb","嘠𪙊蹷齓"],
+["9ff0","跔蹏鸜踁抂𨍽踨蹵竓𤩷稾磘泪詧瘇"],
+["a040","𨩚鼦泎蟖痃𪊲硓咢贌狢獱謭猂瓱賫𤪻蘯徺袠䒷"],
+["a055","𡠻𦸅"],
+["a058","詾𢔛"],
+["a05b","惽癧髗鵄鍮鮏蟵"],
+["a063","蠏賷猬霡鮰㗖犲䰇籑饊𦅙慙䰄麖慽"],
+["a073","坟慯抦戹拎㩜懢厪𣏵捤栂㗒"],
+["a0a1","嵗𨯂迚𨸹"],
+["a0a6","僙𡵆礆匲阸𠼻䁥"],
+["a0ae","矾"],
+["a0b0","糂𥼚糚稭聦聣絍甅瓲覔舚朌聢𧒆聛瓰脃眤覉𦟌畓𦻑螩蟎臈螌詉貭譃眫瓸蓚㘵榲趦"],
+["a0d4","覩瑨涹蟁𤀑瓧㷛煶悤憜㳑煢恷"],
+["a0e2","罱𨬭牐惩䭾删㰘𣳇𥻗𧙖𥔱𡥄𡋾𩤃𦷜𧂭峁𦆭𨨏𣙷𠃮𦡆𤼎䕢嬟𦍌齐麦𦉫"],
+["a3c0","␀",31,"␡"],
+["c6a1","①",9,"⑴",9,"ⅰ",9,"丶丿亅亠冂冖冫勹匸卩厶夊宀巛⼳广廴彐彡攴无疒癶辵隶¨ˆヽヾゝゞ〃仝々〆〇ー［］✽ぁ",23],
+["c740","す",58,"ァアィイ"],
+["c7a1","ゥ",81,"А",5,"ЁЖ",4],
+["c840","Л",26,"ёж",25,"⇧↸↹㇏𠃌乚𠂊刂䒑"],
+["c8a1","龰冈龱𧘇"],
+["c8cd","￢￤＇＂㈱№℡゛゜⺀⺄⺆⺇⺈⺊⺌⺍⺕⺜⺝⺥⺧⺪⺬⺮⺶⺼⺾⻆⻊⻌⻍⻏⻖⻗⻞⻣"],
+["c8f5","ʃɐɛɔɵœøŋʊɪ"],
+["f9fe","￭"],
+["fa40","𠕇鋛𠗟𣿅蕌䊵珯况㙉𤥂𨧤鍄𡧛苮𣳈砼杄拟𤤳𨦪𠊠𦮳𡌅侫𢓭倈𦴩𧪄𣘀𤪱𢔓倩𠍾徤𠎀𠍇滛𠐟偽儁㑺儎顬㝃萖𤦤𠒇兠𣎴兪𠯿𢃼𠋥𢔰𠖎𣈳𡦃宂蝽𠖳𣲙冲冸"],
+["faa1","鴴凉减凑㳜凓𤪦决凢卂凭菍椾𣜭彻刋刦刼劵剗劔効勅簕蕂勠蘍𦬓包𨫞啉滙𣾀𠥔𣿬匳卄𠯢泋𡜦栛珕恊㺪㣌𡛨燝䒢卭却𨚫卾卿𡖖𡘓矦厓𨪛厠厫厮玧𥝲㽙玜叁叅汉义埾叙㪫𠮏叠𣿫𢶣叶𠱷吓灹唫晗浛呭𦭓𠵴啝咏咤䞦𡜍𠻝㶴𠵍"],
+["fb40","𨦼𢚘啇䳭启琗喆喩嘅𡣗𤀺䕒𤐵暳𡂴嘷曍𣊊暤暭噍噏磱囱鞇叾圀囯园𨭦㘣𡉏坆𤆥汮炋坂㚱𦱾埦𡐖堃𡑔𤍣堦𤯵塜墪㕡壠壜𡈼壻寿坃𪅐𤉸鏓㖡够梦㛃湙"],
+["fba1","𡘾娤啓𡚒蔅姉𠵎𦲁𦴪𡟜姙𡟻𡞲𦶦浱𡠨𡛕姹𦹅媫婣㛦𤦩婷㜈媖瑥嫓𦾡𢕔㶅𡤑㜲𡚸広勐孶斈孼𧨎䀄䡝𠈄寕慠𡨴𥧌𠖥寳宝䴐尅𡭄尓珎尔𡲥𦬨屉䣝岅峩峯嶋𡷹𡸷崐崘嵆𡺤岺巗苼㠭𤤁𢁉𢅳芇㠶㯂帮檊幵幺𤒼𠳓厦亷廐厨𡝱帉廴𨒂"],
+["fc40","廹廻㢠廼栾鐛弍𠇁弢㫞䢮𡌺强𦢈𢏐彘𢑱彣鞽𦹮彲鍀𨨶徧嶶㵟𥉐𡽪𧃸𢙨釖𠊞𨨩怱暅𡡷㥣㷇㘹垐𢞴祱㹀悞悤悳𤦂𤦏𧩓璤僡媠慤萤慂慈𦻒憁凴𠙖憇宪𣾷"],
+["fca1","𢡟懓𨮝𩥝懐㤲𢦀𢣁怣慜攞掋𠄘担𡝰拕𢸍捬𤧟㨗搸揸𡎎𡟼撐澊𢸶頔𤂌𥜝擡擥鑻㩦携㩗敍漖𤨨𤨣斅敭敟𣁾斵𤥀䬷旑䃘𡠩无旣忟𣐀昘𣇷𣇸晄𣆤𣆥晋𠹵晧𥇦晳晴𡸽𣈱𨗴𣇈𥌓矅𢣷馤朂𤎜𤨡㬫槺𣟂杞杧杢𤇍𩃭柗䓩栢湐鈼栁𣏦𦶠桝"],
+["fd40","𣑯槡樋𨫟楳棃𣗍椁椀㴲㨁𣘼㮀枬楡𨩊䋼椶榘㮡𠏉荣傐槹𣙙𢄪橅𣜃檝㯳枱櫈𩆜㰍欝𠤣惞欵歴𢟍溵𣫛𠎵𡥘㝀吡𣭚毡𣻼毜氷𢒋𤣱𦭑汚舦汹𣶼䓅𣶽𤆤𤤌𤤀"],
+["fda1","𣳉㛥㳫𠴲鮃𣇹𢒑羏样𦴥𦶡𦷫涖浜湼漄𤥿𤂅𦹲蔳𦽴凇沜渝萮𨬡港𣸯瑓𣾂秌湏媑𣁋濸㜍澝𣸰滺𡒗𤀽䕕鏰潄潜㵎潴𩅰㴻澟𤅄濓𤂑𤅕𤀹𣿰𣾴𤄿凟𤅖𤅗𤅀𦇝灋灾炧炁烌烕烖烟䄄㷨熴熖𤉷焫煅媈煊煮岜𤍥煏鍢𤋁焬𤑚𤨧𤨢熺𨯨炽爎"],
+["fe40","鑂爕夑鑃爤鍁𥘅爮牀𤥴梽牕牗㹕𣁄栍漽犂猪猫𤠣𨠫䣭𨠄猨献珏玪𠰺𦨮珉瑉𤇢𡛧𤨤昣㛅𤦷𤦍𤧻珷琕椃𤨦琹𠗃㻗瑜𢢭瑠𨺲瑇珤瑶莹瑬㜰瑴鏱樬璂䥓𤪌"],
+["fea1","𤅟𤩹𨮏孆𨰃𡢞瓈𡦈甎瓩甞𨻙𡩋寗𨺬鎅畍畊畧畮𤾂㼄𤴓疎瑝疞疴瘂瘬癑癏癯癶𦏵皐臯㟸𦤑𦤎皡皥皷盌𦾟葢𥂝𥅽𡸜眞眦着撯𥈠睘𣊬瞯𨥤𨥨𡛁矴砉𡍶𤨒棊碯磇磓隥礮𥗠磗礴碱𧘌辸袄𨬫𦂃𢘜禆褀椂禀𥡗禝𧬹礼禩渪𧄦㺨秆𩄍秔"]
+]
diff --git a/server/node_modules/iconv-lite/encodings/tables/cp936.json b/server/node_modules/iconv-lite/encodings/tables/cp936.json
new file mode 100644
index 0000000..49ddb9a
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/tables/cp936.json
@@ -0,0 +1,264 @@
+[
+["0","\u0000",127,"€"],
+["8140","丂丄丅丆丏丒丗丟丠両丣並丩丮丯丱丳丵丷丼乀乁乂乄乆乊乑乕乗乚乛乢乣乤乥乧乨乪",5,"乲乴",9,"乿",6,"亇亊"],
+["8180","亐亖亗亙亜亝亞亣亪亯亰亱亴亶亷亸亹亼亽亾仈仌仏仐仒仚仛仜仠仢仦仧仩仭仮仯仱仴仸仹仺仼仾伀伂",6,"伋伌伒",4,"伜伝伡伣伨伩伬伭伮伱伳伵伷伹伻伾",4,"佄佅佇",5,"佒佔佖佡佢佦佨佪佫佭佮佱佲併佷佸佹佺佽侀侁侂侅來侇侊侌侎侐侒侓侕侖侘侙侚侜侞侟価侢"],
+["8240","侤侫侭侰",4,"侶",8,"俀俁係俆俇俈俉俋俌俍俒",4,"俙俛俠俢俤俥俧俫俬俰俲俴俵俶俷俹俻俼俽俿",11],
+["8280","個倎倐們倓倕倖倗倛倝倞倠倢倣値倧倫倯",10,"倻倽倿偀偁偂偄偅偆偉偊偋偍偐",4,"偖偗偘偙偛偝",7,"偦",5,"偭",8,"偸偹偺偼偽傁傂傃傄傆傇傉傊傋傌傎",20,"傤傦傪傫傭",4,"傳",6,"傼"],
+["8340","傽",17,"僐",5,"僗僘僙僛",10,"僨僩僪僫僯僰僱僲僴僶",4,"僼",9,"儈"],
+["8380","儉儊儌",5,"儓",13,"儢",28,"兂兇兊兌兎兏児兒兓兗兘兙兛兝",4,"兣兤兦內兩兪兯兲兺兾兿冃冄円冇冊冋冎冏冐冑冓冔冘冚冝冞冟冡冣冦",4,"冭冮冴冸冹冺冾冿凁凂凃凅凈凊凍凎凐凒",5],
+["8440","凘凙凚凜凞凟凢凣凥",5,"凬凮凱凲凴凷凾刄刅刉刋刌刏刐刓刔刕刜刞刟刡刢刣別刦刧刪刬刯刱刲刴刵刼刾剄",5,"剋剎剏剒剓剕剗剘"],
+["8480","剙剚剛剝剟剠剢剣剤剦剨剫剬剭剮剰剱剳",9,"剾劀劃",4,"劉",6,"劑劒劔",6,"劜劤劥劦劧劮劯劰労",9,"勀勁勂勄勅勆勈勊勌勍勎勏勑勓勔動勗務",5,"勠勡勢勣勥",10,"勱",7,"勻勼勽匁匂匃匄匇匉匊匋匌匎"],
+["8540","匑匒匓匔匘匛匜匞匟匢匤匥匧匨匩匫匬匭匯",9,"匼匽區卂卄卆卋卌卍卐協単卙卛卝卥卨卪卬卭卲卶卹卻卼卽卾厀厁厃厇厈厊厎厏"],
+["8580","厐",4,"厖厗厙厛厜厞厠厡厤厧厪厫厬厭厯",6,"厷厸厹厺厼厽厾叀參",4,"収叏叐叒叓叕叚叜叝叞叡叢叧叴叺叾叿吀吂吅吇吋吔吘吙吚吜吢吤吥吪吰吳吶吷吺吽吿呁呂呄呅呇呉呌呍呎呏呑呚呝",4,"呣呥呧呩",7,"呴呹呺呾呿咁咃咅咇咈咉咊咍咑咓咗咘咜咞咟咠咡"],
+["8640","咢咥咮咰咲咵咶咷咹咺咼咾哃哅哊哋哖哘哛哠",4,"哫哬哯哰哱哴",5,"哻哾唀唂唃唄唅唈唊",4,"唒唓唕",5,"唜唝唞唟唡唥唦"],
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diff --git a/server/node_modules/iconv-lite/encodings/tables/cp949.json b/server/node_modules/iconv-lite/encodings/tables/cp949.json
new file mode 100644
index 0000000..2022a00
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/tables/cp949.json
@@ -0,0 +1,273 @@
+[
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+["bc81","펯",4,"펵펶펷펹펺펻펽",6,"폆폇폊",5,"폑",5,"샥샨샬샴샵샷샹섀섄섈섐섕서",4,"섣설섦섧섬섭섯섰성섶세섹센셀셈셉셋셌셍셔셕션셜셤셥셧셨셩셰셴셸솅소속솎손솔솖솜솝솟송솥솨솩솬솰솽쇄쇈쇌쇔쇗쇘쇠쇤쇨쇰쇱쇳쇼쇽숀숄숌숍숏숑수숙순숟술숨숩숫숭"],
+["bd41","폗폙",7,"폢폤",7,"폮폯폱폲폳폵폶폷"],
+["bd61","폸폹폺폻폾퐀퐂",5,"퐉",13],
+["bd81","퐗",5,"퐞",25,"숯숱숲숴쉈쉐쉑쉔쉘쉠쉥쉬쉭쉰쉴쉼쉽쉿슁슈슉슐슘슛슝스슥슨슬슭슴습슷승시식신싣실싫심십싯싱싶싸싹싻싼쌀쌈쌉쌌쌍쌓쌔쌕쌘쌜쌤쌥쌨쌩썅써썩썬썰썲썸썹썼썽쎄쎈쎌쏀쏘쏙쏜쏟쏠쏢쏨쏩쏭쏴쏵쏸쐈쐐쐤쐬쐰"],
+["be41","퐸",7,"푁푂푃푅",14],
+["be61","푔",7,"푝푞푟푡푢푣푥",7,"푮푰푱푲"],
+["be81","푳",4,"푺푻푽푾풁풃",4,"풊풌풎",5,"풕",8,"쐴쐼쐽쑈쑤쑥쑨쑬쑴쑵쑹쒀쒔쒜쒸쒼쓩쓰쓱쓴쓸쓺쓿씀씁씌씐씔씜씨씩씬씰씸씹씻씽아악안앉않알앍앎앓암압앗았앙앝앞애액앤앨앰앱앳앴앵야약얀얄얇얌얍얏양얕얗얘얜얠얩어억언얹얻얼얽얾엄",6,"엌엎"],
+["bf41","풞",10,"풪",14],
+["bf61","풹",18,"퓍퓎퓏퓑퓒퓓퓕"],
+["bf81","퓖",5,"퓝퓞퓠",7,"퓩퓪퓫퓭퓮퓯퓱",6,"퓹퓺퓼에엑엔엘엠엡엣엥여역엮연열엶엷염",5,"옅옆옇예옌옐옘옙옛옜오옥온올옭옮옰옳옴옵옷옹옻와왁완왈왐왑왓왔왕왜왝왠왬왯왱외왹왼욀욈욉욋욍요욕욘욜욤욥욧용우욱운울욹욺움웁웃웅워웍원월웜웝웠웡웨"],
+["c041","퓾",5,"픅픆픇픉픊픋픍",6,"픖픘",5],
+["c061","픞",25],
+["c081","픸픹픺픻픾픿핁핂핃핅",6,"핎핐핒",5,"핚핛핝핞핟핡핢핣웩웬웰웸웹웽위윅윈윌윔윕윗윙유육윤율윰윱윳융윷으윽은을읊음읍읏응",7,"읜읠읨읫이익인일읽읾잃임입잇있잉잊잎자작잔잖잗잘잚잠잡잣잤장잦재잭잰잴잼잽잿쟀쟁쟈쟉쟌쟎쟐쟘쟝쟤쟨쟬저적전절젊"],
+["c141","핤핦핧핪핬핮",5,"핶핷핹핺핻핽",6,"햆햊햋"],
+["c161","햌햍햎햏햑",19,"햦햧"],
+["c181","햨",31,"점접젓정젖제젝젠젤젬젭젯젱져젼졀졈졉졌졍졔조족존졸졺좀좁좃종좆좇좋좌좍좔좝좟좡좨좼좽죄죈죌죔죕죗죙죠죡죤죵주죽준줄줅줆줌줍줏중줘줬줴쥐쥑쥔쥘쥠쥡쥣쥬쥰쥴쥼즈즉즌즐즘즙즛증지직진짇질짊짐집짓"],
+["c241","헊헋헍헎헏헑헓",4,"헚헜헞",5,"헦헧헩헪헫헭헮"],
+["c261","헯",4,"헶헸헺",5,"혂혃혅혆혇혉",6,"혒"],
+["c281","혖",5,"혝혞혟혡혢혣혥",7,"혮",9,"혺혻징짖짙짚짜짝짠짢짤짧짬짭짯짰짱째짹짼쨀쨈쨉쨋쨌쨍쨔쨘쨩쩌쩍쩐쩔쩜쩝쩟쩠쩡쩨쩽쪄쪘쪼쪽쫀쫄쫌쫍쫏쫑쫓쫘쫙쫠쫬쫴쬈쬐쬔쬘쬠쬡쭁쭈쭉쭌쭐쭘쭙쭝쭤쭸쭹쮜쮸쯔쯤쯧쯩찌찍찐찔찜찝찡찢찧차착찬찮찰참찹찻"],
+["c341","혽혾혿홁홂홃홄홆홇홊홌홎홏홐홒홓홖홗홙홚홛홝",4],
+["c361","홢",4,"홨홪",5,"홲홳홵",11],
+["c381","횁횂횄횆",5,"횎횏횑횒횓횕",7,"횞횠횢",5,"횩횪찼창찾채책챈챌챔챕챗챘챙챠챤챦챨챰챵처척천철첨첩첫첬청체첵첸첼쳄쳅쳇쳉쳐쳔쳤쳬쳰촁초촉촌촐촘촙촛총촤촨촬촹최쵠쵤쵬쵭쵯쵱쵸춈추축춘출춤춥춧충춰췄췌췐취췬췰췸췹췻췽츄츈츌츔츙츠측츤츨츰츱츳층"],
+["c441","횫횭횮횯횱",7,"횺횼",7,"훆훇훉훊훋"],
+["c461","훍훎훏훐훒훓훕훖훘훚",5,"훡훢훣훥훦훧훩",4],
+["c481","훮훯훱훲훳훴훶",5,"훾훿휁휂휃휅",11,"휒휓휔치칙친칟칠칡침칩칫칭카칵칸칼캄캅캇캉캐캑캔캘캠캡캣캤캥캬캭컁커컥컨컫컬컴컵컷컸컹케켁켄켈켐켑켓켕켜켠켤켬켭켯켰켱켸코콕콘콜콤콥콧콩콰콱콴콸쾀쾅쾌쾡쾨쾰쿄쿠쿡쿤쿨쿰쿱쿳쿵쿼퀀퀄퀑퀘퀭퀴퀵퀸퀼"],
+["c541","휕휖휗휚휛휝휞휟휡",6,"휪휬휮",5,"휶휷휹"],
+["c561","휺휻휽",6,"흅흆흈흊",5,"흒흓흕흚",4],
+["c581","흟흢흤흦흧흨흪흫흭흮흯흱흲흳흵",6,"흾흿힀힂",5,"힊힋큄큅큇큉큐큔큘큠크큭큰클큼큽킁키킥킨킬킴킵킷킹타탁탄탈탉탐탑탓탔탕태택탠탤탬탭탯탰탱탸턍터턱턴털턺텀텁텃텄텅테텍텐텔템텝텟텡텨텬텼톄톈토톡톤톨톰톱톳통톺톼퇀퇘퇴퇸툇툉툐투툭툰툴툼툽툿퉁퉈퉜"],
+["c641","힍힎힏힑",6,"힚힜힞",5],
+["c6a1","퉤튀튁튄튈튐튑튕튜튠튤튬튱트특튼튿틀틂틈틉틋틔틘틜틤틥티틱틴틸팀팁팃팅파팍팎판팔팖팜팝팟팠팡팥패팩팬팰팸팹팻팼팽퍄퍅퍼퍽펀펄펌펍펏펐펑페펙펜펠펨펩펫펭펴편펼폄폅폈평폐폘폡폣포폭폰폴폼폽폿퐁"],
+["c7a1","퐈퐝푀푄표푠푤푭푯푸푹푼푿풀풂품풉풋풍풔풩퓌퓐퓔퓜퓟퓨퓬퓰퓸퓻퓽프픈플픔픕픗피픽핀필핌핍핏핑하학한할핥함합핫항해핵핸핼햄햅햇했행햐향허헉헌헐헒험헙헛헝헤헥헨헬헴헵헷헹혀혁현혈혐협혓혔형혜혠"],
+["c8a1","혤혭호혹혼홀홅홈홉홋홍홑화확환활홧황홰홱홴횃횅회획횐횔횝횟횡효횬횰횹횻후훅훈훌훑훔훗훙훠훤훨훰훵훼훽휀휄휑휘휙휜휠휨휩휫휭휴휵휸휼흄흇흉흐흑흔흖흗흘흙흠흡흣흥흩희흰흴흼흽힁히힉힌힐힘힙힛힝"],
+["caa1","伽佳假價加可呵哥嘉嫁家暇架枷柯歌珂痂稼苛茄街袈訶賈跏軻迦駕刻却各恪慤殼珏脚覺角閣侃刊墾奸姦干幹懇揀杆柬桿澗癎看磵稈竿簡肝艮艱諫間乫喝曷渴碣竭葛褐蝎鞨勘坎堪嵌感憾戡敢柑橄減甘疳監瞰紺邯鑑鑒龕"],
+["cba1","匣岬甲胛鉀閘剛堈姜岡崗康强彊慷江畺疆糠絳綱羌腔舡薑襁講鋼降鱇介价個凱塏愷愾慨改槪漑疥皆盖箇芥蓋豈鎧開喀客坑更粳羹醵倨去居巨拒据據擧渠炬祛距踞車遽鉅鋸乾件健巾建愆楗腱虔蹇鍵騫乞傑杰桀儉劍劒檢"],
+["cca1","瞼鈐黔劫怯迲偈憩揭擊格檄激膈覡隔堅牽犬甄絹繭肩見譴遣鵑抉決潔結缺訣兼慊箝謙鉗鎌京俓倞傾儆勁勍卿坰境庚徑慶憬擎敬景暻更梗涇炅烱璟璥瓊痙硬磬竟競絅經耕耿脛莖警輕逕鏡頃頸驚鯨係啓堺契季屆悸戒桂械"],
+["cda1","棨溪界癸磎稽系繫繼計誡谿階鷄古叩告呱固姑孤尻庫拷攷故敲暠枯槁沽痼皐睾稿羔考股膏苦苽菰藁蠱袴誥賈辜錮雇顧高鼓哭斛曲梏穀谷鵠困坤崑昆梱棍滾琨袞鯤汨滑骨供公共功孔工恐恭拱控攻珙空蚣貢鞏串寡戈果瓜"],
+["cea1","科菓誇課跨過鍋顆廓槨藿郭串冠官寬慣棺款灌琯瓘管罐菅觀貫關館刮恝括适侊光匡壙廣曠洸炚狂珖筐胱鑛卦掛罫乖傀塊壞怪愧拐槐魁宏紘肱轟交僑咬喬嬌嶠巧攪敎校橋狡皎矯絞翹膠蕎蛟較轎郊餃驕鮫丘久九仇俱具勾"],
+["cfa1","區口句咎嘔坵垢寇嶇廐懼拘救枸柩構歐毆毬求溝灸狗玖球瞿矩究絿耉臼舅舊苟衢謳購軀逑邱鉤銶駒驅鳩鷗龜國局菊鞠鞫麴君窘群裙軍郡堀屈掘窟宮弓穹窮芎躬倦券勸卷圈拳捲權淃眷厥獗蕨蹶闕机櫃潰詭軌饋句晷歸貴"],
+["d0a1","鬼龜叫圭奎揆槻珪硅窺竅糾葵規赳逵閨勻均畇筠菌鈞龜橘克剋劇戟棘極隙僅劤勤懃斤根槿瑾筋芹菫覲謹近饉契今妗擒昑檎琴禁禽芩衾衿襟金錦伋及急扱汲級給亘兢矜肯企伎其冀嗜器圻基埼夔奇妓寄岐崎己幾忌技旗旣"],
+["d1a1","朞期杞棋棄機欺氣汽沂淇玘琦琪璂璣畸畿碁磯祁祇祈祺箕紀綺羈耆耭肌記譏豈起錡錤飢饑騎騏驥麒緊佶吉拮桔金喫儺喇奈娜懦懶拏拿癩",5,"那樂",4,"諾酪駱亂卵暖欄煖爛蘭難鸞捏捺南嵐枏楠湳濫男藍襤拉"],
+["d2a1","納臘蠟衲囊娘廊",4,"乃來內奈柰耐冷女年撚秊念恬拈捻寧寗努勞奴弩怒擄櫓爐瑙盧",5,"駑魯",10,"濃籠聾膿農惱牢磊腦賂雷尿壘",7,"嫩訥杻紐勒",5,"能菱陵尼泥匿溺多茶"],
+["d3a1","丹亶但單團壇彖斷旦檀段湍短端簞緞蛋袒鄲鍛撻澾獺疸達啖坍憺擔曇淡湛潭澹痰聃膽蕁覃談譚錟沓畓答踏遝唐堂塘幢戇撞棠當糖螳黨代垈坮大對岱帶待戴擡玳臺袋貸隊黛宅德悳倒刀到圖堵塗導屠島嶋度徒悼挑掉搗桃"],
+["d4a1","棹櫂淘渡滔濤燾盜睹禱稻萄覩賭跳蹈逃途道都鍍陶韜毒瀆牘犢獨督禿篤纛讀墩惇敦旽暾沌焞燉豚頓乭突仝冬凍動同憧東桐棟洞潼疼瞳童胴董銅兜斗杜枓痘竇荳讀豆逗頭屯臀芚遁遯鈍得嶝橙燈登等藤謄鄧騰喇懶拏癩羅"],
+["d5a1","蘿螺裸邏樂洛烙珞絡落諾酪駱丹亂卵欄欒瀾爛蘭鸞剌辣嵐擥攬欖濫籃纜藍襤覽拉臘蠟廊朗浪狼琅瑯螂郞來崍徠萊冷掠略亮倆兩凉梁樑粮粱糧良諒輛量侶儷勵呂廬慮戾旅櫚濾礪藜蠣閭驢驪麗黎力曆歷瀝礫轢靂憐戀攣漣"],
+["d6a1","煉璉練聯蓮輦連鍊冽列劣洌烈裂廉斂殮濂簾獵令伶囹寧岺嶺怜玲笭羚翎聆逞鈴零靈領齡例澧禮醴隷勞怒撈擄櫓潞瀘爐盧老蘆虜路輅露魯鷺鹵碌祿綠菉錄鹿麓論壟弄朧瀧瓏籠聾儡瀨牢磊賂賚賴雷了僚寮廖料燎療瞭聊蓼"],
+["d7a1","遼鬧龍壘婁屢樓淚漏瘻累縷蔞褸鏤陋劉旒柳榴流溜瀏琉瑠留瘤硫謬類六戮陸侖倫崙淪綸輪律慄栗率隆勒肋凜凌楞稜綾菱陵俚利厘吏唎履悧李梨浬犁狸理璃異痢籬罹羸莉裏裡里釐離鯉吝潾燐璘藺躪隣鱗麟林淋琳臨霖砬"],
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+["eea1","障再哉在宰才材栽梓渽滓災縡裁財載齋齎爭箏諍錚佇低儲咀姐底抵杵楮樗沮渚狙猪疽箸紵苧菹著藷詛貯躇這邸雎齟勣吊嫡寂摘敵滴狄炙的積笛籍績翟荻謫賊赤跡蹟迪迹適鏑佃佺傳全典前剪塡塼奠專展廛悛戰栓殿氈澱"],
+["efa1","煎琠田甸畑癲筌箋箭篆纏詮輾轉鈿銓錢鐫電顚顫餞切截折浙癤竊節絶占岾店漸点粘霑鮎點接摺蝶丁井亭停偵呈姃定幀庭廷征情挺政整旌晶晸柾楨檉正汀淀淨渟湞瀞炡玎珽町睛碇禎程穽精綎艇訂諪貞鄭酊釘鉦鋌錠霆靖"],
+["f0a1","靜頂鼎制劑啼堤帝弟悌提梯濟祭第臍薺製諸蹄醍除際霽題齊俎兆凋助嘲弔彫措操早晁曺曹朝條棗槽漕潮照燥爪璪眺祖祚租稠窕粗糟組繰肇藻蚤詔調趙躁造遭釣阻雕鳥族簇足鏃存尊卒拙猝倧宗從悰慫棕淙琮種終綜縱腫"],
+["f1a1","踪踵鍾鐘佐坐左座挫罪主住侏做姝胄呪周嗾奏宙州廚晝朱柱株注洲湊澍炷珠疇籌紂紬綢舟蛛註誅走躊輳週酎酒鑄駐竹粥俊儁准埈寯峻晙樽浚準濬焌畯竣蠢逡遵雋駿茁中仲衆重卽櫛楫汁葺增憎曾拯烝甑症繒蒸證贈之只"],
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+["f3a1","鏶集徵懲澄且侘借叉嗟嵯差次此磋箚茶蹉車遮捉搾着窄錯鑿齪撰澯燦璨瓚竄簒纂粲纘讚贊鑽餐饌刹察擦札紮僭參塹慘慙懺斬站讒讖倉倡創唱娼廠彰愴敞昌昶暢槍滄漲猖瘡窓脹艙菖蒼債埰寀寨彩採砦綵菜蔡采釵冊柵策"],
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+["f6a1","贅取吹嘴娶就炊翠聚脆臭趣醉驟鷲側仄厠惻測層侈値嗤峙幟恥梔治淄熾痔痴癡稚穉緇緻置致蚩輜雉馳齒則勅飭親七柒漆侵寢枕沈浸琛砧針鍼蟄秤稱快他咤唾墮妥惰打拖朶楕舵陀馱駝倬卓啄坼度托拓擢晫柝濁濯琢琸託"],
+["f7a1","鐸呑嘆坦彈憚歎灘炭綻誕奪脫探眈耽貪塔搭榻宕帑湯糖蕩兌台太怠態殆汰泰笞胎苔跆邰颱宅擇澤撑攄兎吐土討慟桶洞痛筒統通堆槌腿褪退頹偸套妬投透鬪慝特闖坡婆巴把播擺杷波派爬琶破罷芭跛頗判坂板版瓣販辦鈑"],
+["f8a1","阪八叭捌佩唄悖敗沛浿牌狽稗覇貝彭澎烹膨愎便偏扁片篇編翩遍鞭騙貶坪平枰萍評吠嬖幣廢弊斃肺蔽閉陛佈包匍匏咆哺圃布怖抛抱捕暴泡浦疱砲胞脯苞葡蒲袍褒逋鋪飽鮑幅暴曝瀑爆輻俵剽彪慓杓標漂瓢票表豹飇飄驃"],
+["f9a1","品稟楓諷豊風馮彼披疲皮被避陂匹弼必泌珌畢疋筆苾馝乏逼下何厦夏廈昰河瑕荷蝦賀遐霞鰕壑學虐謔鶴寒恨悍旱汗漢澣瀚罕翰閑閒限韓割轄函含咸啣喊檻涵緘艦銜陷鹹合哈盒蛤閤闔陜亢伉姮嫦巷恒抗杭桁沆港缸肛航"],
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diff --git a/server/node_modules/iconv-lite/encodings/tables/cp950.json b/server/node_modules/iconv-lite/encodings/tables/cp950.json
new file mode 100644
index 0000000..d8bc871
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/tables/cp950.json
@@ -0,0 +1,177 @@
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+["e1a1","寣屣嶂嶀嵽嶆嵺嶁嵷嶊嶉嶈嵾嵼嶍嵹嵿幘幙幓廘廑廗廎廜廕廙廒廔彄彃彯徶愬愨慁慞慱慳慒慓慲慬憀慴慔慺慛慥愻慪慡慖戩戧戫搫摍摛摝摴摶摲摳摽摵摦撦摎撂摞摜摋摓摠摐摿搿摬摫摙摥摷敳斠暡暠暟朅朄朢榱榶槉"],
+["e240","榠槎榖榰榬榼榑榙榎榧榍榩榾榯榿槄榽榤槔榹槊榚槏榳榓榪榡榞槙榗榐槂榵榥槆歊歍歋殞殟殠毃毄毾滎滵滱漃漥滸漷滻漮漉潎漙漚漧漘漻漒滭漊"],
+["e2a1","漶潳滹滮漭潀漰漼漵滫漇漎潃漅滽滶漹漜滼漺漟漍漞漈漡熇熐熉熀熅熂熏煻熆熁熗牄牓犗犕犓獃獍獑獌瑢瑳瑱瑵瑲瑧瑮甀甂甃畽疐瘖瘈瘌瘕瘑瘊瘔皸瞁睼瞅瞂睮瞀睯睾瞃碲碪碴碭碨硾碫碞碥碠碬碢碤禘禊禋禖禕禔禓"],
+["e340","禗禈禒禐稫穊稰稯稨稦窨窫窬竮箈箜箊箑箐箖箍箌箛箎箅箘劄箙箤箂粻粿粼粺綧綷緂綣綪緁緀緅綝緎緄緆緋緌綯綹綖綼綟綦綮綩綡緉罳翢翣翥翞"],
+["e3a1","耤聝聜膉膆膃膇膍膌膋舕蒗蒤蒡蒟蒺蓎蓂蒬蒮蒫蒹蒴蓁蓍蒪蒚蒱蓐蒝蒧蒻蒢蒔蓇蓌蒛蒩蒯蒨蓖蒘蒶蓏蒠蓗蓔蓒蓛蒰蒑虡蜳蜣蜨蝫蝀蜮蜞蜡蜙蜛蝃蜬蝁蜾蝆蜠蜲蜪蜭蜼蜒蜺蜱蜵蝂蜦蜧蜸蜤蜚蜰蜑裷裧裱裲裺裾裮裼裶裻"],
+["e440","裰裬裫覝覡覟覞觩觫觨誫誙誋誒誏誖谽豨豩賕賏賗趖踉踂跿踍跽踊踃踇踆踅跾踀踄輐輑輎輍鄣鄜鄠鄢鄟鄝鄚鄤鄡鄛酺酲酹酳銥銤鉶銛鉺銠銔銪銍"],
+["e4a1","銦銚銫鉹銗鉿銣鋮銎銂銕銢鉽銈銡銊銆銌銙銧鉾銇銩銝銋鈭隞隡雿靘靽靺靾鞃鞀鞂靻鞄鞁靿韎韍頖颭颮餂餀餇馝馜駃馹馻馺駂馽駇骱髣髧鬾鬿魠魡魟鳱鳲鳵麧僿儃儰僸儆儇僶僾儋儌僽儊劋劌勱勯噈噂噌嘵噁噊噉噆噘"],
+["e540","噚噀嘳嘽嘬嘾嘸嘪嘺圚墫墝墱墠墣墯墬墥墡壿嫿嫴嫽嫷嫶嬃嫸嬂嫹嬁嬇嬅嬏屧嶙嶗嶟嶒嶢嶓嶕嶠嶜嶡嶚嶞幩幝幠幜緳廛廞廡彉徲憋憃慹憱憰憢憉"],
+["e5a1","憛憓憯憭憟憒憪憡憍慦憳戭摮摰撖撠撅撗撜撏撋撊撌撣撟摨撱撘敶敺敹敻斲斳暵暰暩暲暷暪暯樀樆樗槥槸樕槱槤樠槿槬槢樛樝槾樧槲槮樔槷槧橀樈槦槻樍槼槫樉樄樘樥樏槶樦樇槴樖歑殥殣殢殦氁氀毿氂潁漦潾澇濆澒"],
+["e640","澍澉澌潢潏澅潚澖潶潬澂潕潲潒潐潗澔澓潝漀潡潫潽潧澐潓澋潩潿澕潣潷潪潻熲熯熛熰熠熚熩熵熝熥熞熤熡熪熜熧熳犘犚獘獒獞獟獠獝獛獡獚獙"],
+["e6a1","獢璇璉璊璆璁瑽璅璈瑼瑹甈甇畾瘥瘞瘙瘝瘜瘣瘚瘨瘛皜皝皞皛瞍瞏瞉瞈磍碻磏磌磑磎磔磈磃磄磉禚禡禠禜禢禛歶稹窲窴窳箷篋箾箬篎箯箹篊箵糅糈糌糋緷緛緪緧緗緡縃緺緦緶緱緰緮緟罶羬羰羭翭翫翪翬翦翨聤聧膣膟"],
+["e740","膞膕膢膙膗舖艏艓艒艐艎艑蔤蔻蔏蔀蔩蔎蔉蔍蔟蔊蔧蔜蓻蔫蓺蔈蔌蓴蔪蓲蔕蓷蓫蓳蓼蔒蓪蓩蔖蓾蔨蔝蔮蔂蓽蔞蓶蔱蔦蓧蓨蓰蓯蓹蔘蔠蔰蔋蔙蔯虢"],
+["e7a1","蝖蝣蝤蝷蟡蝳蝘蝔蝛蝒蝡蝚蝑蝞蝭蝪蝐蝎蝟蝝蝯蝬蝺蝮蝜蝥蝏蝻蝵蝢蝧蝩衚褅褌褔褋褗褘褙褆褖褑褎褉覢覤覣觭觰觬諏諆誸諓諑諔諕誻諗誾諀諅諘諃誺誽諙谾豍貏賥賟賙賨賚賝賧趠趜趡趛踠踣踥踤踮踕踛踖踑踙踦踧"],
+["e840","踔踒踘踓踜踗踚輬輤輘輚輠輣輖輗遳遰遯遧遫鄯鄫鄩鄪鄲鄦鄮醅醆醊醁醂醄醀鋐鋃鋄鋀鋙銶鋏鋱鋟鋘鋩鋗鋝鋌鋯鋂鋨鋊鋈鋎鋦鋍鋕鋉鋠鋞鋧鋑鋓"],
+["e8a1","銵鋡鋆銴镼閬閫閮閰隤隢雓霅霈霂靚鞊鞎鞈韐韏頞頝頦頩頨頠頛頧颲餈飺餑餔餖餗餕駜駍駏駓駔駎駉駖駘駋駗駌骳髬髫髳髲髱魆魃魧魴魱魦魶魵魰魨魤魬鳼鳺鳽鳿鳷鴇鴀鳹鳻鴈鴅鴄麃黓鼏鼐儜儓儗儚儑凞匴叡噰噠噮"],
+["e940","噳噦噣噭噲噞噷圜圛壈墽壉墿墺壂墼壆嬗嬙嬛嬡嬔嬓嬐嬖嬨嬚嬠嬞寯嶬嶱嶩嶧嶵嶰嶮嶪嶨嶲嶭嶯嶴幧幨幦幯廩廧廦廨廥彋徼憝憨憖懅憴懆懁懌憺"],
+["e9a1","憿憸憌擗擖擐擏擉撽撉擃擛擳擙攳敿敼斢曈暾曀曊曋曏暽暻暺曌朣樴橦橉橧樲橨樾橝橭橶橛橑樨橚樻樿橁橪橤橐橏橔橯橩橠樼橞橖橕橍橎橆歕歔歖殧殪殫毈毇氄氃氆澭濋澣濇澼濎濈潞濄澽澞濊澨瀄澥澮澺澬澪濏澿澸"],
+["ea40","澢濉澫濍澯澲澰燅燂熿熸燖燀燁燋燔燊燇燏熽燘熼燆燚燛犝犞獩獦獧獬獥獫獪瑿璚璠璔璒璕璡甋疀瘯瘭瘱瘽瘳瘼瘵瘲瘰皻盦瞚瞝瞡瞜瞛瞢瞣瞕瞙"],
+["eaa1","瞗磝磩磥磪磞磣磛磡磢磭磟磠禤穄穈穇窶窸窵窱窷篞篣篧篝篕篥篚篨篹篔篪篢篜篫篘篟糒糔糗糐糑縒縡縗縌縟縠縓縎縜縕縚縢縋縏縖縍縔縥縤罃罻罼罺羱翯耪耩聬膱膦膮膹膵膫膰膬膴膲膷膧臲艕艖艗蕖蕅蕫蕍蕓蕡蕘"],
+["eb40","蕀蕆蕤蕁蕢蕄蕑蕇蕣蔾蕛蕱蕎蕮蕵蕕蕧蕠薌蕦蕝蕔蕥蕬虣虥虤螛螏螗螓螒螈螁螖螘蝹螇螣螅螐螑螝螄螔螜螚螉褞褦褰褭褮褧褱褢褩褣褯褬褟觱諠"],
+["eba1","諢諲諴諵諝謔諤諟諰諈諞諡諨諿諯諻貑貒貐賵賮賱賰賳赬赮趥趧踳踾踸蹀蹅踶踼踽蹁踰踿躽輶輮輵輲輹輷輴遶遹遻邆郺鄳鄵鄶醓醐醑醍醏錧錞錈錟錆錏鍺錸錼錛錣錒錁鍆錭錎錍鋋錝鋺錥錓鋹鋷錴錂錤鋿錩錹錵錪錔錌"],
+["ec40","錋鋾錉錀鋻錖閼闍閾閹閺閶閿閵閽隩雔霋霒霐鞙鞗鞔韰韸頵頯頲餤餟餧餩馞駮駬駥駤駰駣駪駩駧骹骿骴骻髶髺髹髷鬳鮀鮅鮇魼魾魻鮂鮓鮒鮐魺鮕"],
+["eca1","魽鮈鴥鴗鴠鴞鴔鴩鴝鴘鴢鴐鴙鴟麈麆麇麮麭黕黖黺鼒鼽儦儥儢儤儠儩勴嚓嚌嚍嚆嚄嚃噾嚂噿嚁壖壔壏壒嬭嬥嬲嬣嬬嬧嬦嬯嬮孻寱寲嶷幬幪徾徻懃憵憼懧懠懥懤懨懞擯擩擣擫擤擨斁斀斶旚曒檍檖檁檥檉檟檛檡檞檇檓檎"],
+["ed40","檕檃檨檤檑橿檦檚檅檌檒歛殭氉濌澩濴濔濣濜濭濧濦濞濲濝濢濨燡燱燨燲燤燰燢獳獮獯璗璲璫璐璪璭璱璥璯甐甑甒甏疄癃癈癉癇皤盩瞵瞫瞲瞷瞶"],
+["eda1","瞴瞱瞨矰磳磽礂磻磼磲礅磹磾礄禫禨穜穛穖穘穔穚窾竀竁簅簏篲簀篿篻簎篴簋篳簂簉簃簁篸篽簆篰篱簐簊糨縭縼繂縳顈縸縪繉繀繇縩繌縰縻縶繄縺罅罿罾罽翴翲耬膻臄臌臊臅臇膼臩艛艚艜薃薀薏薧薕薠薋薣蕻薤薚薞"],
+["ee40","蕷蕼薉薡蕺蕸蕗薎薖薆薍薙薝薁薢薂薈薅蕹蕶薘薐薟虨螾螪螭蟅螰螬螹螵螼螮蟉蟃蟂蟌螷螯蟄蟊螴螶螿螸螽蟞螲褵褳褼褾襁襒褷襂覭覯覮觲觳謞"],
+["eea1","謘謖謑謅謋謢謏謒謕謇謍謈謆謜謓謚豏豰豲豱豯貕貔賹赯蹎蹍蹓蹐蹌蹇轃轀邅遾鄸醚醢醛醙醟醡醝醠鎡鎃鎯鍤鍖鍇鍼鍘鍜鍶鍉鍐鍑鍠鍭鎏鍌鍪鍹鍗鍕鍒鍏鍱鍷鍻鍡鍞鍣鍧鎀鍎鍙闇闀闉闃闅閷隮隰隬霠霟霘霝霙鞚鞡鞜"],
+["ef40","鞞鞝韕韔韱顁顄顊顉顅顃餥餫餬餪餳餲餯餭餱餰馘馣馡騂駺駴駷駹駸駶駻駽駾駼騃骾髾髽鬁髼魈鮚鮨鮞鮛鮦鮡鮥鮤鮆鮢鮠鮯鴳鵁鵧鴶鴮鴯鴱鴸鴰"],
+["efa1","鵅鵂鵃鴾鴷鵀鴽翵鴭麊麉麍麰黈黚黻黿鼤鼣鼢齔龠儱儭儮嚘嚜嚗嚚嚝嚙奰嬼屩屪巀幭幮懘懟懭懮懱懪懰懫懖懩擿攄擽擸攁攃擼斔旛曚曛曘櫅檹檽櫡櫆檺檶檷櫇檴檭歞毉氋瀇瀌瀍瀁瀅瀔瀎濿瀀濻瀦濼濷瀊爁燿燹爃燽獶"],
+["f040","璸瓀璵瓁璾璶璻瓂甔甓癜癤癙癐癓癗癚皦皽盬矂瞺磿礌礓礔礉礐礒礑禭禬穟簜簩簙簠簟簭簝簦簨簢簥簰繜繐繖繣繘繢繟繑繠繗繓羵羳翷翸聵臑臒"],
+["f0a1","臐艟艞薴藆藀藃藂薳薵薽藇藄薿藋藎藈藅薱薶藒蘤薸薷薾虩蟧蟦蟢蟛蟫蟪蟥蟟蟳蟤蟔蟜蟓蟭蟘蟣螤蟗蟙蠁蟴蟨蟝襓襋襏襌襆襐襑襉謪謧謣謳謰謵譇謯謼謾謱謥謷謦謶謮謤謻謽謺豂豵貙貘貗賾贄贂贀蹜蹢蹠蹗蹖蹞蹥蹧"],
+["f140","蹛蹚蹡蹝蹩蹔轆轇轈轋鄨鄺鄻鄾醨醥醧醯醪鎵鎌鎒鎷鎛鎝鎉鎧鎎鎪鎞鎦鎕鎈鎙鎟鎍鎱鎑鎲鎤鎨鎴鎣鎥闒闓闑隳雗雚巂雟雘雝霣霢霥鞬鞮鞨鞫鞤鞪"],
+["f1a1","鞢鞥韗韙韖韘韺顐顑顒颸饁餼餺騏騋騉騍騄騑騊騅騇騆髀髜鬈鬄鬅鬩鬵魊魌魋鯇鯆鯃鮿鯁鮵鮸鯓鮶鯄鮹鮽鵜鵓鵏鵊鵛鵋鵙鵖鵌鵗鵒鵔鵟鵘鵚麎麌黟鼁鼀鼖鼥鼫鼪鼩鼨齌齕儴儵劖勷厴嚫嚭嚦嚧嚪嚬壚壝壛夒嬽嬾嬿巃幰"],
+["f240","徿懻攇攐攍攉攌攎斄旞旝曞櫧櫠櫌櫑櫙櫋櫟櫜櫐櫫櫏櫍櫞歠殰氌瀙瀧瀠瀖瀫瀡瀢瀣瀩瀗瀤瀜瀪爌爊爇爂爅犥犦犤犣犡瓋瓅璷瓃甖癠矉矊矄矱礝礛"],
+["f2a1","礡礜礗礞禰穧穨簳簼簹簬簻糬糪繶繵繸繰繷繯繺繲繴繨罋罊羃羆羷翽翾聸臗臕艤艡艣藫藱藭藙藡藨藚藗藬藲藸藘藟藣藜藑藰藦藯藞藢蠀蟺蠃蟶蟷蠉蠌蠋蠆蟼蠈蟿蠊蠂襢襚襛襗襡襜襘襝襙覈覷覶觶譐譈譊譀譓譖譔譋譕"],
+["f340","譑譂譒譗豃豷豶貚贆贇贉趬趪趭趫蹭蹸蹳蹪蹯蹻軂轒轑轏轐轓辴酀鄿醰醭鏞鏇鏏鏂鏚鏐鏹鏬鏌鏙鎩鏦鏊鏔鏮鏣鏕鏄鏎鏀鏒鏧镽闚闛雡霩霫霬霨霦"],
+["f3a1","鞳鞷鞶韝韞韟顜顙顝顗颿颽颻颾饈饇饃馦馧騚騕騥騝騤騛騢騠騧騣騞騜騔髂鬋鬊鬎鬌鬷鯪鯫鯠鯞鯤鯦鯢鯰鯔鯗鯬鯜鯙鯥鯕鯡鯚鵷鶁鶊鶄鶈鵱鶀鵸鶆鶋鶌鵽鵫鵴鵵鵰鵩鶅鵳鵻鶂鵯鵹鵿鶇鵨麔麑黀黼鼭齀齁齍齖齗齘匷嚲"],
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+]
diff --git a/server/node_modules/iconv-lite/encodings/tables/eucjp.json b/server/node_modules/iconv-lite/encodings/tables/eucjp.json
new file mode 100644
index 0000000..4fa61ca
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/tables/eucjp.json
@@ -0,0 +1,182 @@
+[
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+["8ea1","｡",62],
+["a1a1","　、。，．・：；？！゛゜´｀¨＾￣＿ヽヾゝゞ〃仝々〆〇ー―‐／＼～∥｜…‥‘’“”（）〔〕［］｛｝〈",9,"＋－±×÷＝≠＜＞≦≧∞∴♂♀°′″℃￥＄￠￡％＃＆＊＠§☆★○●◎◇"],
+["a2a1","◆□■△▲▽▼※〒→←↑↓〓"],
+["a2ba","∈∋⊆⊇⊂⊃∪∩"],
+["a2ca","∧∨￢⇒⇔∀∃"],
+["a2dc","∠⊥⌒∂∇≡≒≪≫√∽∝∵∫∬"],
+["a2f2","Å‰♯♭♪†‡¶"],
+["a2fe","◯"],
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+["a3c1","Ａ",25],
+["a3e1","ａ",25],
+["a4a1","ぁ",82],
+["a5a1","ァ",85],
+["a6a1","Α",16,"Σ",6],
+["a6c1","α",16,"σ",6],
+["a7a1","А",5,"ЁЖ",25],
+["a7d1","а",5,"ёж",25],
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+["ada1","①",19,"Ⅰ",9],
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+["c5a1","邸鄭釘鼎泥摘擢敵滴的笛適鏑溺哲徹撤轍迭鉄典填天展店添纏甜貼転顛点伝殿澱田電兎吐堵塗妬屠徒斗杜渡登菟賭途都鍍砥砺努度土奴怒倒党冬凍刀唐塔塘套宕島嶋悼投搭東桃梼棟盗淘湯涛灯燈当痘祷等答筒糖統到"],
+["c6a1","董蕩藤討謄豆踏逃透鐙陶頭騰闘働動同堂導憧撞洞瞳童胴萄道銅峠鴇匿得徳涜特督禿篤毒独読栃橡凸突椴届鳶苫寅酉瀞噸屯惇敦沌豚遁頓呑曇鈍奈那内乍凪薙謎灘捺鍋楢馴縄畷南楠軟難汝二尼弐迩匂賑肉虹廿日乳入"],
+["c7a1","如尿韮任妊忍認濡禰祢寧葱猫熱年念捻撚燃粘乃廼之埜嚢悩濃納能脳膿農覗蚤巴把播覇杷波派琶破婆罵芭馬俳廃拝排敗杯盃牌背肺輩配倍培媒梅楳煤狽買売賠陪這蝿秤矧萩伯剥博拍柏泊白箔粕舶薄迫曝漠爆縛莫駁麦"],
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+["c9a1","鼻柊稗匹疋髭彦膝菱肘弼必畢筆逼桧姫媛紐百謬俵彪標氷漂瓢票表評豹廟描病秒苗錨鋲蒜蛭鰭品彬斌浜瀕貧賓頻敏瓶不付埠夫婦富冨布府怖扶敷斧普浮父符腐膚芙譜負賦赴阜附侮撫武舞葡蕪部封楓風葺蕗伏副復幅服"],
+["caa1","福腹複覆淵弗払沸仏物鮒分吻噴墳憤扮焚奮粉糞紛雰文聞丙併兵塀幣平弊柄並蔽閉陛米頁僻壁癖碧別瞥蔑箆偏変片篇編辺返遍便勉娩弁鞭保舗鋪圃捕歩甫補輔穂募墓慕戊暮母簿菩倣俸包呆報奉宝峰峯崩庖抱捧放方朋"],
+["cba1","法泡烹砲縫胞芳萌蓬蜂褒訪豊邦鋒飽鳳鵬乏亡傍剖坊妨帽忘忙房暴望某棒冒紡肪膨謀貌貿鉾防吠頬北僕卜墨撲朴牧睦穆釦勃没殆堀幌奔本翻凡盆摩磨魔麻埋妹昧枚毎哩槙幕膜枕鮪柾鱒桝亦俣又抹末沫迄侭繭麿万慢満"],
+["cca1","漫蔓味未魅巳箕岬密蜜湊蓑稔脈妙粍民眠務夢無牟矛霧鵡椋婿娘冥名命明盟迷銘鳴姪牝滅免棉綿緬面麺摸模茂妄孟毛猛盲網耗蒙儲木黙目杢勿餅尤戻籾貰問悶紋門匁也冶夜爺耶野弥矢厄役約薬訳躍靖柳薮鑓愉愈油癒"],
+["cda1","諭輸唯佑優勇友宥幽悠憂揖有柚湧涌猶猷由祐裕誘遊邑郵雄融夕予余与誉輿預傭幼妖容庸揚揺擁曜楊様洋溶熔用窯羊耀葉蓉要謡踊遥陽養慾抑欲沃浴翌翼淀羅螺裸来莱頼雷洛絡落酪乱卵嵐欄濫藍蘭覧利吏履李梨理璃"],
+["cea1","痢裏裡里離陸律率立葎掠略劉流溜琉留硫粒隆竜龍侶慮旅虜了亮僚両凌寮料梁涼猟療瞭稜糧良諒遼量陵領力緑倫厘林淋燐琳臨輪隣鱗麟瑠塁涙累類令伶例冷励嶺怜玲礼苓鈴隷零霊麗齢暦歴列劣烈裂廉恋憐漣煉簾練聯"],
+["cfa1","蓮連錬呂魯櫓炉賂路露労婁廊弄朗楼榔浪漏牢狼篭老聾蝋郎六麓禄肋録論倭和話歪賄脇惑枠鷲亙亘鰐詫藁蕨椀湾碗腕"],
+["d0a1","弌丐丕个丱丶丼丿乂乖乘亂亅豫亊舒弍于亞亟亠亢亰亳亶从仍仄仆仂仗仞仭仟价伉佚估佛佝佗佇佶侈侏侘佻佩佰侑佯來侖儘俔俟俎俘俛俑俚俐俤俥倚倨倔倪倥倅伜俶倡倩倬俾俯們倆偃假會偕偐偈做偖偬偸傀傚傅傴傲"],
+["d1a1","僉僊傳僂僖僞僥僭僣僮價僵儉儁儂儖儕儔儚儡儺儷儼儻儿兀兒兌兔兢竸兩兪兮冀冂囘册冉冏冑冓冕冖冤冦冢冩冪冫决冱冲冰况冽凅凉凛几處凩凭凰凵凾刄刋刔刎刧刪刮刳刹剏剄剋剌剞剔剪剴剩剳剿剽劍劔劒剱劈劑辨"],
+["d2a1","辧劬劭劼劵勁勍勗勞勣勦飭勠勳勵勸勹匆匈甸匍匐匏匕匚匣匯匱匳匸區卆卅丗卉卍凖卞卩卮夘卻卷厂厖厠厦厥厮厰厶參簒雙叟曼燮叮叨叭叺吁吽呀听吭吼吮吶吩吝呎咏呵咎呟呱呷呰咒呻咀呶咄咐咆哇咢咸咥咬哄哈咨"],
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+["d5a1","奸妁妝佞侫妣妲姆姨姜妍姙姚娥娟娑娜娉娚婀婬婉娵娶婢婪媚媼媾嫋嫂媽嫣嫗嫦嫩嫖嫺嫻嬌嬋嬖嬲嫐嬪嬶嬾孃孅孀孑孕孚孛孥孩孰孳孵學斈孺宀它宦宸寃寇寉寔寐寤實寢寞寥寫寰寶寳尅將專對尓尠尢尨尸尹屁屆屎屓"],
+["d6a1","屐屏孱屬屮乢屶屹岌岑岔妛岫岻岶岼岷峅岾峇峙峩峽峺峭嶌峪崋崕崗嵜崟崛崑崔崢崚崙崘嵌嵒嵎嵋嵬嵳嵶嶇嶄嶂嶢嶝嶬嶮嶽嶐嶷嶼巉巍巓巒巖巛巫已巵帋帚帙帑帛帶帷幄幃幀幎幗幔幟幢幤幇幵并幺麼广庠廁廂廈廐廏"],
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+["d8a1","悄悛悖悗悒悧悋惡悸惠惓悴忰悽惆悵惘慍愕愆惶惷愀惴惺愃愡惻惱愍愎慇愾愨愧慊愿愼愬愴愽慂慄慳慷慘慙慚慫慴慯慥慱慟慝慓慵憙憖憇憬憔憚憊憑憫憮懌懊應懷懈懃懆憺懋罹懍懦懣懶懺懴懿懽懼懾戀戈戉戍戌戔戛"],
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+["daa1","據擒擅擇撻擘擂擱擧舉擠擡抬擣擯攬擶擴擲擺攀擽攘攜攅攤攣攫攴攵攷收攸畋效敖敕敍敘敞敝敲數斂斃變斛斟斫斷旃旆旁旄旌旒旛旙无旡旱杲昊昃旻杳昵昶昴昜晏晄晉晁晞晝晤晧晨晟晢晰暃暈暎暉暄暘暝曁暹曉暾暼"],
+["dba1","曄暸曖曚曠昿曦曩曰曵曷朏朖朞朦朧霸朮朿朶杁朸朷杆杞杠杙杣杤枉杰枩杼杪枌枋枦枡枅枷柯枴柬枳柩枸柤柞柝柢柮枹柎柆柧檜栞框栩桀桍栲桎梳栫桙档桷桿梟梏梭梔條梛梃檮梹桴梵梠梺椏梍桾椁棊椈棘椢椦棡椌棍"],
+["dca1","棔棧棕椶椒椄棗棣椥棹棠棯椨椪椚椣椡棆楹楷楜楸楫楔楾楮椹楴椽楙椰楡楞楝榁楪榲榮槐榿槁槓榾槎寨槊槝榻槃榧樮榑榠榜榕榴槞槨樂樛槿權槹槲槧樅榱樞槭樔槫樊樒櫁樣樓橄樌橲樶橸橇橢橙橦橈樸樢檐檍檠檄檢檣"],
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+["e3a1","磧磚磽磴礇礒礑礙礬礫祀祠祗祟祚祕祓祺祿禊禝禧齋禪禮禳禹禺秉秕秧秬秡秣稈稍稘稙稠稟禀稱稻稾稷穃穗穉穡穢穩龝穰穹穽窈窗窕窘窖窩竈窰窶竅竄窿邃竇竊竍竏竕竓站竚竝竡竢竦竭竰笂笏笊笆笳笘笙笞笵笨笶筐"],
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+["8fd1a1","秠秢秥秪秫秭秱秸秼稂稃稇稉稊稌稑稕稛稞稡稧稫稭稯稰稴稵稸稹稺穄穅穇穈穌穕穖穙穜穝穟穠穥穧穪穭穵穸穾窀窂窅窆窊窋窐窑窔窞窠窣窬窳窵窹窻窼竆竉竌竎竑竛竨竩竫竬竱竴竻竽竾笇笔笟笣笧笩笪笫笭笮笯笰"],
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+["8fdca1","蠺蠼衁衃衅衈衉衊衋衎衑衕衖衘衚衜衟衠衤衩衱衹衻袀袘袚袛袜袟袠袨袪袺袽袾裀裊",4,"裑裒裓裛裞裧裯裰裱裵裷褁褆褍褎褏褕褖褘褙褚褜褠褦褧褨褰褱褲褵褹褺褾襀襂襅襆襉襏襒襗襚襛襜襡襢襣襫襮襰襳襵襺"],
+["8fdda1","襻襼襽覉覍覐覔覕覛覜覟覠覥覰覴覵覶覷覼觔",4,"觥觩觫觭觱觳觶觹觽觿訄訅訇訏訑訒訔訕訞訠訢訤訦訫訬訯訵訷訽訾詀詃詅詇詉詍詎詓詖詗詘詜詝詡詥詧詵詶詷詹詺詻詾詿誀誃誆誋誏誐誒誖誗誙誟誧誩誮誯誳"],
+["8fdea1","誶誷誻誾諃諆諈諉諊諑諓諔諕諗諝諟諬諰諴諵諶諼諿謅謆謋謑謜謞謟謊謭謰謷謼譂",4,"譈譒譓譔譙譍譞譣譭譶譸譹譼譾讁讄讅讋讍讏讔讕讜讞讟谸谹谽谾豅豇豉豋豏豑豓豔豗豘豛豝豙豣豤豦豨豩豭豳豵豶豻豾貆"],
+["8fdfa1","貇貋貐貒貓貙貛貜貤貹貺賅賆賉賋賏賖賕賙賝賡賨賬賯賰賲賵賷賸賾賿贁贃贉贒贗贛赥赩赬赮赿趂趄趈趍趐趑趕趞趟趠趦趫趬趯趲趵趷趹趻跀跅跆跇跈跊跎跑跔跕跗跙跤跥跧跬跰趼跱跲跴跽踁踄踅踆踋踑踔踖踠踡踢"],
+["8fe0a1","踣踦踧踱踳踶踷踸踹踽蹀蹁蹋蹍蹎蹏蹔蹛蹜蹝蹞蹡蹢蹩蹬蹭蹯蹰蹱蹹蹺蹻躂躃躉躐躒躕躚躛躝躞躢躧躩躭躮躳躵躺躻軀軁軃軄軇軏軑軔軜軨軮軰軱軷軹軺軭輀輂輇輈輏輐輖輗輘輞輠輡輣輥輧輨輬輭輮輴輵輶輷輺轀轁"],
+["8fe1a1","轃轇轏轑",4,"轘轝轞轥辝辠辡辤辥辦辵辶辸达迀迁迆迊迋迍运迒迓迕迠迣迤迨迮迱迵迶迻迾适逄逈逌逘逛逨逩逯逪逬逭逳逴逷逿遃遄遌遛遝遢遦遧遬遰遴遹邅邈邋邌邎邐邕邗邘邙邛邠邡邢邥邰邲邳邴邶邽郌邾郃"],
+["8fe2a1","郄郅郇郈郕郗郘郙郜郝郟郥郒郶郫郯郰郴郾郿鄀鄄鄅鄆鄈鄍鄐鄔鄖鄗鄘鄚鄜鄞鄠鄥鄢鄣鄧鄩鄮鄯鄱鄴鄶鄷鄹鄺鄼鄽酃酇酈酏酓酗酙酚酛酡酤酧酭酴酹酺酻醁醃醅醆醊醎醑醓醔醕醘醞醡醦醨醬醭醮醰醱醲醳醶醻醼醽醿"],
+["8fe3a1","釂釃釅釓釔釗釙釚釞釤釥釩釪釬",5,"釷釹釻釽鈀鈁鈄鈅鈆鈇鈉鈊鈌鈐鈒鈓鈖鈘鈜鈝鈣鈤鈥鈦鈨鈮鈯鈰鈳鈵鈶鈸鈹鈺鈼鈾鉀鉂鉃鉆鉇鉊鉍鉎鉏鉑鉘鉙鉜鉝鉠鉡鉥鉧鉨鉩鉮鉯鉰鉵",4,"鉻鉼鉽鉿銈銉銊銍銎銒銗"],
+["8fe4a1","銙銟銠銤銥銧銨銫銯銲銶銸銺銻銼銽銿",4,"鋅鋆鋇鋈鋋鋌鋍鋎鋐鋓鋕鋗鋘鋙鋜鋝鋟鋠鋡鋣鋥鋧鋨鋬鋮鋰鋹鋻鋿錀錂錈錍錑錔錕錜錝錞錟錡錤錥錧錩錪錳錴錶錷鍇鍈鍉鍐鍑鍒鍕鍗鍘鍚鍞鍤鍥鍧鍩鍪鍭鍯鍰鍱鍳鍴鍶"],
+["8fe5a1","鍺鍽鍿鎀鎁鎂鎈鎊鎋鎍鎏鎒鎕鎘鎛鎞鎡鎣鎤鎦鎨鎫鎴鎵鎶鎺鎩鏁鏄鏅鏆鏇鏉",4,"鏓鏙鏜鏞鏟鏢鏦鏧鏹鏷鏸鏺鏻鏽鐁鐂鐄鐈鐉鐍鐎鐏鐕鐖鐗鐟鐮鐯鐱鐲鐳鐴鐻鐿鐽鑃鑅鑈鑊鑌鑕鑙鑜鑟鑡鑣鑨鑫鑭鑮鑯鑱鑲钄钃镸镹"],
+["8fe6a1","镾閄閈閌閍閎閝閞閟閡閦閩閫閬閴閶閺閽閿闆闈闉闋闐闑闒闓闙闚闝闞闟闠闤闦阝阞阢阤阥阦阬阱阳阷阸阹阺阼阽陁陒陔陖陗陘陡陮陴陻陼陾陿隁隂隃隄隉隑隖隚隝隟隤隥隦隩隮隯隳隺雊雒嶲雘雚雝雞雟雩雯雱雺霂"],
+["8fe7a1","霃霅霉霚霛霝霡霢霣霨霱霳靁靃靊靎靏靕靗靘靚靛靣靧靪靮靳靶靷靸靻靽靿鞀鞉鞕鞖鞗鞙鞚鞞鞟鞢鞬鞮鞱鞲鞵鞶鞸鞹鞺鞼鞾鞿韁韄韅韇韉韊韌韍韎韐韑韔韗韘韙韝韞韠韛韡韤韯韱韴韷韸韺頇頊頙頍頎頔頖頜頞頠頣頦"],
+["8fe8a1","頫頮頯頰頲頳頵頥頾顄顇顊顑顒顓顖顗顙顚顢顣顥顦顪顬颫颭颮颰颴颷颸颺颻颿飂飅飈飌飡飣飥飦飧飪飳飶餂餇餈餑餕餖餗餚餛餜餟餢餦餧餫餱",4,"餹餺餻餼饀饁饆饇饈饍饎饔饘饙饛饜饞饟饠馛馝馟馦馰馱馲馵"],
+["8fe9a1","馹馺馽馿駃駉駓駔駙駚駜駞駧駪駫駬駰駴駵駹駽駾騂騃騄騋騌騐騑騖騞騠騢騣騤騧騭騮騳騵騶騸驇驁驄驊驋驌驎驑驔驖驝骪骬骮骯骲骴骵骶骹骻骾骿髁髃髆髈髎髐髒髕髖髗髛髜髠髤髥髧髩髬髲髳髵髹髺髽髿",4],
+["8feaa1","鬄鬅鬈鬉鬋鬌鬍鬎鬐鬒鬖鬙鬛鬜鬠鬦鬫鬭鬳鬴鬵鬷鬹鬺鬽魈魋魌魕魖魗魛魞魡魣魥魦魨魪",4,"魳魵魷魸魹魿鮀鮄鮅鮆鮇鮉鮊鮋鮍鮏鮐鮔鮚鮝鮞鮦鮧鮩鮬鮰鮱鮲鮷鮸鮻鮼鮾鮿鯁鯇鯈鯎鯐鯗鯘鯝鯟鯥鯧鯪鯫鯯鯳鯷鯸"],
+["8feba1","鯹鯺鯽鯿鰀鰂鰋鰏鰑鰖鰘鰙鰚鰜鰞鰢鰣鰦",4,"鰱鰵鰶鰷鰽鱁鱃鱄鱅鱉鱊鱎鱏鱐鱓鱔鱖鱘鱛鱝鱞鱟鱣鱩鱪鱜鱫鱨鱮鱰鱲鱵鱷鱻鳦鳲鳷鳹鴋鴂鴑鴗鴘鴜鴝鴞鴯鴰鴲鴳鴴鴺鴼鵅鴽鵂鵃鵇鵊鵓鵔鵟鵣鵢鵥鵩鵪鵫鵰鵶鵷鵻"],
+["8feca1","鵼鵾鶃鶄鶆鶊鶍鶎鶒鶓鶕鶖鶗鶘鶡鶪鶬鶮鶱鶵鶹鶼鶿鷃鷇鷉鷊鷔鷕鷖鷗鷚鷞鷟鷠鷥鷧鷩鷫鷮鷰鷳鷴鷾鸊鸂鸇鸎鸐鸑鸒鸕鸖鸙鸜鸝鹺鹻鹼麀麂麃麄麅麇麎麏麖麘麛麞麤麨麬麮麯麰麳麴麵黆黈黋黕黟黤黧黬黭黮黰黱黲黵"],
+["8feda1","黸黿鼂鼃鼉鼏鼐鼑鼒鼔鼖鼗鼙鼚鼛鼟鼢鼦鼪鼫鼯鼱鼲鼴鼷鼹鼺鼼鼽鼿齁齃",4,"齓齕齖齗齘齚齝齞齨齩齭",4,"齳齵齺齽龏龐龑龒龔龖龗龞龡龢龣龥"]
+]
diff --git a/server/node_modules/iconv-lite/encodings/tables/gb18030-ranges.json b/server/node_modules/iconv-lite/encodings/tables/gb18030-ranges.json
new file mode 100644
index 0000000..85c6934
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/tables/gb18030-ranges.json
@@ -0,0 +1 @@
+{"uChars":[128,165,169,178,184,216,226,235,238,244,248,251,253,258,276,284,300,325,329,334,364,463,465,467,469,471,473,475,477,506,594,610,712,716,730,930,938,962,970,1026,1104,1106,8209,8215,8218,8222,8231,8241,8244,8246,8252,8365,8452,8454,8458,8471,8482,8556,8570,8596,8602,8713,8720,8722,8726,8731,8737,8740,8742,8748,8751,8760,8766,8777,8781,8787,8802,8808,8816,8854,8858,8870,8896,8979,9322,9372,9548,9588,9616,9622,9634,9652,9662,9672,9676,9680,9702,9735,9738,9793,9795,11906,11909,11913,11917,11928,11944,11947,11951,11956,11960,11964,11979,12284,12292,12312,12319,12330,12351,12436,12447,12535,12543,12586,12842,12850,12964,13200,13215,13218,13253,13263,13267,13270,13384,13428,13727,13839,13851,14617,14703,14801,14816,14964,15183,15471,15585,16471,16736,17208,17325,17330,17374,17623,17997,18018,18212,18218,18301,18318,18760,18811,18814,18820,18823,18844,18848,18872,19576,19620,19738,19887,40870,59244,59336,59367,59413,59417,59423,59431,59437,59443,59452,59460,59478,59493,63789,63866,63894,63976,63986,64016,64018,64021,64025,64034,64037,64042,65074,65093,65107,65112,65127,65132,65375,65510,65536],"gbChars":[0,36,38,45,50,81,89,95,96,100,103,104,105,109,126,133,148,172,175,179,208,306,307,308,309,310,311,312,313,341,428,443,544,545,558,741,742,749,750,805,819,820,7922,7924,7925,7927,7934,7943,7944,7945,7950,8062,8148,8149,8152,8164,8174,8236,8240,8262,8264,8374,8380,8381,8384,8388,8390,8392,8393,8394,8396,8401,8406,8416,8419,8424,8437,8439,8445,8482,8485,8496,8521,8603,8936,8946,9046,9050,9063,9066,9076,9092,9100,9108,9111,9113,9131,9162,9164,9218,9219,11329,11331,11334,11336,11346,11361,11363,11366,11370,11372,11375,11389,11682,11686,11687,11692,11694,11714,11716,11723,11725,11730,11736,11982,11989,12102,12336,12348,12350,12384,12393,12395,12397,12510,12553,12851,12962,12973,13738,13823,13919,13933,14080,14298,14585,14698,15583,15847,16318,16434,16438,16481,16729,17102,17122,17315,17320,17402,17418,17859,17909,17911,17915,17916,17936,17939,17961,18664,18703,18814,18962,19043,33469,33470,33471,33484,33485,33490,33497,33501,33505,33513,33520,33536,33550,37845,37921,37948,38029,38038,38064,38065,38066,38069,38075,38076,38078,39108,39109,39113,39114,39115,39116,39265,39394,189000]}
\ No newline at end of file
diff --git a/server/node_modules/iconv-lite/encodings/tables/gbk-added.json b/server/node_modules/iconv-lite/encodings/tables/gbk-added.json
new file mode 100644
index 0000000..8abfa9f
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/tables/gbk-added.json
@@ -0,0 +1,55 @@
+[
+["a140","",62],
+["a180","",32],
+["a240","",62],
+["a280","",32],
+["a2ab","",5],
+["a2e3","€"],
+["a2ef",""],
+["a2fd",""],
+["a340","",62],
+["a380","",31,"　"],
+["a440","",62],
+["a480","",32],
+["a4f4","",10],
+["a540","",62],
+["a580","",32],
+["a5f7","",7],
+["a640","",62],
+["a680","",32],
+["a6b9","",7],
+["a6d9","",6],
+["a6ec",""],
+["a6f3",""],
+["a6f6","",8],
+["a740","",62],
+["a780","",32],
+["a7c2","",14],
+["a7f2","",12],
+["a896","",10],
+["a8bc",""],
+["a8bf","ǹ"],
+["a8c1",""],
+["a8ea","",20],
+["a958",""],
+["a95b",""],
+["a95d",""],
+["a989","〾⿰",11],
+["a997","",12],
+["a9f0","",14],
+["aaa1","",93],
+["aba1","",93],
+["aca1","",93],
+["ada1","",93],
+["aea1","",93],
+["afa1","",93],
+["d7fa","",4],
+["f8a1","",93],
+["f9a1","",93],
+["faa1","",93],
+["fba1","",93],
+["fca1","",93],
+["fda1","",93],
+["fe50","⺁⺄㑳㑇⺈⺋㖞㘚㘎⺌⺗㥮㤘㧏㧟㩳㧐㭎㱮㳠⺧⺪䁖䅟⺮䌷⺳⺶⺷䎱䎬⺻䏝䓖䙡䙌"],
+["fe80","䜣䜩䝼䞍⻊䥇䥺䥽䦂䦃䦅䦆䦟䦛䦷䦶䲣䲟䲠䲡䱷䲢䴓",6,"䶮",93]
+]
diff --git a/server/node_modules/iconv-lite/encodings/tables/shiftjis.json b/server/node_modules/iconv-lite/encodings/tables/shiftjis.json
new file mode 100644
index 0000000..5a3a43c
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/tables/shiftjis.json
@@ -0,0 +1,125 @@
+[
+["0","\u0000",128],
+["a1","｡",62],
+["8140","　、。，．・：；？！゛゜´｀¨＾￣＿ヽヾゝゞ〃仝々〆〇ー―‐／＼～∥｜…‥‘’“”（）〔〕［］｛｝〈",9,"＋－±×"],
+["8180","÷＝≠＜＞≦≧∞∴♂♀°′″℃￥＄￠￡％＃＆＊＠§☆★○●◎◇◆□■△▲▽▼※〒→←↑↓〓"],
+["81b8","∈∋⊆⊇⊂⊃∪∩"],
+["81c8","∧∨￢⇒⇔∀∃"],
+["81da","∠⊥⌒∂∇≡≒≪≫√∽∝∵∫∬"],
+["81f0","Å‰♯♭♪†‡¶"],
+["81fc","◯"],
+["824f","０",9],
+["8260","Ａ",25],
+["8281","ａ",25],
+["829f","ぁ",82],
+["8340","ァ",62],
+["8380","ム",22],
+["839f","Α",16,"Σ",6],
+["83bf","α",16,"σ",6],
+["8440","А",5,"ЁЖ",25],
+["8470","а",5,"ёж",7],
+["8480","о",17],
+["849f","─│┌┐┘└├┬┤┴┼━┃┏┓┛┗┣┳┫┻╋┠┯┨┷┿┝┰┥┸╂"],
+["8740","①",19,"Ⅰ",9],
+["875f","㍉㌔㌢㍍㌘㌧㌃㌶㍑㍗㌍㌦㌣㌫㍊㌻㎜㎝㎞㎎㎏㏄㎡"],
+["877e","㍻"],
+["8780","〝〟№㏍℡㊤",4,"㈱㈲㈹㍾㍽㍼≒≡∫∮∑√⊥∠∟⊿∵∩∪"],
+["889f","亜唖娃阿哀愛挨姶逢葵茜穐悪握渥旭葦芦鯵梓圧斡扱宛姐虻飴絢綾鮎或粟袷安庵按暗案闇鞍杏以伊位依偉囲夷委威尉惟意慰易椅為畏異移維緯胃萎衣謂違遺医井亥域育郁磯一壱溢逸稲茨芋鰯允印咽員因姻引飲淫胤蔭"],
+["8940","院陰隠韻吋右宇烏羽迂雨卯鵜窺丑碓臼渦嘘唄欝蔚鰻姥厩浦瓜閏噂云運雲荏餌叡営嬰影映曳栄永泳洩瑛盈穎頴英衛詠鋭液疫益駅悦謁越閲榎厭円"],
+["8980","園堰奄宴延怨掩援沿演炎焔煙燕猿縁艶苑薗遠鉛鴛塩於汚甥凹央奥往応押旺横欧殴王翁襖鴬鴎黄岡沖荻億屋憶臆桶牡乙俺卸恩温穏音下化仮何伽価佳加可嘉夏嫁家寡科暇果架歌河火珂禍禾稼箇花苛茄荷華菓蝦課嘩貨迦過霞蚊俄峨我牙画臥芽蛾賀雅餓駕介会解回塊壊廻快怪悔恢懐戒拐改"],
+["8a40","魁晦械海灰界皆絵芥蟹開階貝凱劾外咳害崖慨概涯碍蓋街該鎧骸浬馨蛙垣柿蛎鈎劃嚇各廓拡撹格核殻獲確穫覚角赫較郭閣隔革学岳楽額顎掛笠樫"],
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+["fa80","兤冝冾凬刕劜劦勀勛匀匇匤卲厓厲叝﨎咜咊咩哿喆坙坥垬埈埇﨏塚增墲夋奓奛奝奣妤妺孖寀甯寘寬尞岦岺峵崧嵓﨑嵂嵭嶸嶹巐弡弴彧德忞恝悅悊惞惕愠惲愑愷愰憘戓抦揵摠撝擎敎昀昕昻昉昮昞昤晥晗晙晴晳暙暠暲暿曺朎朗杦枻桒柀栁桄棏﨓楨﨔榘槢樰橫橆橳橾櫢櫤毖氿汜沆汯泚洄涇浯"],
+["fb40","涖涬淏淸淲淼渹湜渧渼溿澈澵濵瀅瀇瀨炅炫焏焄煜煆煇凞燁燾犱犾猤猪獷玽珉珖珣珒琇珵琦琪琩琮瑢璉璟甁畯皂皜皞皛皦益睆劯砡硎硤硺礰礼神"],
+["fb80","祥禔福禛竑竧靖竫箞精絈絜綷綠緖繒罇羡羽茁荢荿菇菶葈蒴蕓蕙蕫﨟薰蘒﨡蠇裵訒訷詹誧誾諟諸諶譓譿賰賴贒赶﨣軏﨤逸遧郞都鄕鄧釚釗釞釭釮釤釥鈆鈐鈊鈺鉀鈼鉎鉙鉑鈹鉧銧鉷鉸鋧鋗鋙鋐﨧鋕鋠鋓錥錡鋻﨨錞鋿錝錂鍰鍗鎤鏆鏞鏸鐱鑅鑈閒隆﨩隝隯霳霻靃靍靏靑靕顗顥飯飼餧館馞驎髙"],
+["fc40","髜魵魲鮏鮱鮻鰀鵰鵫鶴鸙黑"]
+]
diff --git a/server/node_modules/iconv-lite/encodings/utf16.js b/server/node_modules/iconv-lite/encodings/utf16.js
new file mode 100644
index 0000000..54765ae
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/utf16.js
@@ -0,0 +1,177 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// Note: UTF16-LE (or UCS2) codec is Node.js native. See encodings/internal.js
+
+// == UTF16-BE codec. ==========================================================
+
+exports.utf16be = Utf16BECodec;
+function Utf16BECodec() {
+}
+
+Utf16BECodec.prototype.encoder = Utf16BEEncoder;
+Utf16BECodec.prototype.decoder = Utf16BEDecoder;
+Utf16BECodec.prototype.bomAware = true;
+
+
+// -- Encoding
+
+function Utf16BEEncoder() {
+}
+
+Utf16BEEncoder.prototype.write = function(str) {
+    var buf = Buffer.from(str, 'ucs2');
+    for (var i = 0; i < buf.length; i += 2) {
+        var tmp = buf[i]; buf[i] = buf[i+1]; buf[i+1] = tmp;
+    }
+    return buf;
+}
+
+Utf16BEEncoder.prototype.end = function() {
+}
+
+
+// -- Decoding
+
+function Utf16BEDecoder() {
+    this.overflowByte = -1;
+}
+
+Utf16BEDecoder.prototype.write = function(buf) {
+    if (buf.length == 0)
+        return '';
+
+    var buf2 = Buffer.alloc(buf.length + 1),
+        i = 0, j = 0;
+
+    if (this.overflowByte !== -1) {
+        buf2[0] = buf[0];
+        buf2[1] = this.overflowByte;
+        i = 1; j = 2;
+    }
+
+    for (; i < buf.length-1; i += 2, j+= 2) {
+        buf2[j] = buf[i+1];
+        buf2[j+1] = buf[i];
+    }
+
+    this.overflowByte = (i == buf.length-1) ? buf[buf.length-1] : -1;
+
+    return buf2.slice(0, j).toString('ucs2');
+}
+
+Utf16BEDecoder.prototype.end = function() {
+}
+
+
+// == UTF-16 codec =============================================================
+// Decoder chooses automatically from UTF-16LE and UTF-16BE using BOM and space-based heuristic.
+// Defaults to UTF-16LE, as it's prevalent and default in Node.
+// http://en.wikipedia.org/wiki/UTF-16 and http://encoding.spec.whatwg.org/#utf-16le
+// Decoder default can be changed: iconv.decode(buf, 'utf16', {defaultEncoding: 'utf-16be'});
+
+// Encoder uses UTF-16LE and prepends BOM (which can be overridden with addBOM: false).
+
+exports.utf16 = Utf16Codec;
+function Utf16Codec(codecOptions, iconv) {
+    this.iconv = iconv;
+}
+
+Utf16Codec.prototype.encoder = Utf16Encoder;
+Utf16Codec.prototype.decoder = Utf16Decoder;
+
+
+// -- Encoding (pass-through)
+
+function Utf16Encoder(options, codec) {
+    options = options || {};
+    if (options.addBOM === undefined)
+        options.addBOM = true;
+    this.encoder = codec.iconv.getEncoder('utf-16le', options);
+}
+
+Utf16Encoder.prototype.write = function(str) {
+    return this.encoder.write(str);
+}
+
+Utf16Encoder.prototype.end = function() {
+    return this.encoder.end();
+}
+
+
+// -- Decoding
+
+function Utf16Decoder(options, codec) {
+    this.decoder = null;
+    this.initialBytes = [];
+    this.initialBytesLen = 0;
+
+    this.options = options || {};
+    this.iconv = codec.iconv;
+}
+
+Utf16Decoder.prototype.write = function(buf) {
+    if (!this.decoder) {
+        // Codec is not chosen yet. Accumulate initial bytes.
+        this.initialBytes.push(buf);
+        this.initialBytesLen += buf.length;
+        
+        if (this.initialBytesLen < 16) // We need more bytes to use space heuristic (see below)
+            return '';
+
+        // We have enough bytes -> detect endianness.
+        var buf = Buffer.concat(this.initialBytes),
+            encoding = detectEncoding(buf, this.options.defaultEncoding);
+        this.decoder = this.iconv.getDecoder(encoding, this.options);
+        this.initialBytes.length = this.initialBytesLen = 0;
+    }
+
+    return this.decoder.write(buf);
+}
+
+Utf16Decoder.prototype.end = function() {
+    if (!this.decoder) {
+        var buf = Buffer.concat(this.initialBytes),
+            encoding = detectEncoding(buf, this.options.defaultEncoding);
+        this.decoder = this.iconv.getDecoder(encoding, this.options);
+
+        var res = this.decoder.write(buf),
+            trail = this.decoder.end();
+
+        return trail ? (res + trail) : res;
+    }
+    return this.decoder.end();
+}
+
+function detectEncoding(buf, defaultEncoding) {
+    var enc = defaultEncoding || 'utf-16le';
+
+    if (buf.length >= 2) {
+        // Check BOM.
+        if (buf[0] == 0xFE && buf[1] == 0xFF) // UTF-16BE BOM
+            enc = 'utf-16be';
+        else if (buf[0] == 0xFF && buf[1] == 0xFE) // UTF-16LE BOM
+            enc = 'utf-16le';
+        else {
+            // No BOM found. Try to deduce encoding from initial content.
+            // Most of the time, the content has ASCII chars (U+00**), but the opposite (U+**00) is uncommon.
+            // So, we count ASCII as if it was LE or BE, and decide from that.
+            var asciiCharsLE = 0, asciiCharsBE = 0, // Counts of chars in both positions
+                _len = Math.min(buf.length - (buf.length % 2), 64); // Len is always even.
+
+            for (var i = 0; i < _len; i += 2) {
+                if (buf[i] === 0 && buf[i+1] !== 0) asciiCharsBE++;
+                if (buf[i] !== 0 && buf[i+1] === 0) asciiCharsLE++;
+            }
+
+            if (asciiCharsBE > asciiCharsLE)
+                enc = 'utf-16be';
+            else if (asciiCharsBE < asciiCharsLE)
+                enc = 'utf-16le';
+        }
+    }
+
+    return enc;
+}
+
+
diff --git a/server/node_modules/iconv-lite/encodings/utf7.js b/server/node_modules/iconv-lite/encodings/utf7.js
new file mode 100644
index 0000000..b7631c2
--- /dev/null
+++ b/server/node_modules/iconv-lite/encodings/utf7.js
@@ -0,0 +1,290 @@
+"use strict";
+var Buffer = require("safer-buffer").Buffer;
+
+// UTF-7 codec, according to https://tools.ietf.org/html/rfc2152
+// See also below a UTF-7-IMAP codec, according to http://tools.ietf.org/html/rfc3501#section-5.1.3
+
+exports.utf7 = Utf7Codec;
+exports.unicode11utf7 = 'utf7'; // Alias UNICODE-1-1-UTF-7
+function Utf7Codec(codecOptions, iconv) {
+    this.iconv = iconv;
+};
+
+Utf7Codec.prototype.encoder = Utf7Encoder;
+Utf7Codec.prototype.decoder = Utf7Decoder;
+Utf7Codec.prototype.bomAware = true;
+
+
+// -- Encoding
+
+var nonDirectChars = /[^A-Za-z0-9',-\.\/:\? \n\r\t]+/g;
+
+function Utf7Encoder(options, codec) {
+    this.iconv = codec.iconv;
+}
+
+Utf7Encoder.prototype.write = function(str) {
+    // Naive implementation.
+    // Non-direct chars are encoded as "+<base64>-"; single "+" char is encoded as "+-".
+    return Buffer.from(str.replace(nonDirectChars, function(chunk) {
+        return "+" + (chunk === '+' ? '' : 
+            this.iconv.encode(chunk, 'utf16-be').toString('base64').replace(/=+$/, '')) 
+            + "-";
+    }.bind(this)));
+}
+
+Utf7Encoder.prototype.end = function() {
+}
+
+
+// -- Decoding
+
+function Utf7Decoder(options, codec) {
+    this.iconv = codec.iconv;
+    this.inBase64 = false;
+    this.base64Accum = '';
+}
+
+var base64Regex = /[A-Za-z0-9\/+]/;
+var base64Chars = [];
+for (var i = 0; i < 256; i++)
+    base64Chars[i] = base64Regex.test(String.fromCharCode(i));
+
+var plusChar = '+'.charCodeAt(0), 
+    minusChar = '-'.charCodeAt(0),
+    andChar = '&'.charCodeAt(0);
+
+Utf7Decoder.prototype.write = function(buf) {
+    var res = "", lastI = 0,
+        inBase64 = this.inBase64,
+        base64Accum = this.base64Accum;
+
+    // The decoder is more involved as we must handle chunks in stream.
+
+    for (var i = 0; i < buf.length; i++) {
+        if (!inBase64) { // We're in direct mode.
+            // Write direct chars until '+'
+            if (buf[i] == plusChar) {
+                res += this.iconv.decode(buf.slice(lastI, i), "ascii"); // Write direct chars.
+                lastI = i+1;
+                inBase64 = true;
+            }
+        } else { // We decode base64.
+            if (!base64Chars[buf[i]]) { // Base64 ended.
+                if (i == lastI && buf[i] == minusChar) {// "+-" -> "+"
+                    res += "+";
+                } else {
+                    var b64str = base64Accum + buf.slice(lastI, i).toString();
+                    res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
+                }
+
+                if (buf[i] != minusChar) // Minus is absorbed after base64.
+                    i--;
+
+                lastI = i+1;
+                inBase64 = false;
+                base64Accum = '';
+            }
+        }
+    }
+
+    if (!inBase64) {
+        res += this.iconv.decode(buf.slice(lastI), "ascii"); // Write direct chars.
+    } else {
+        var b64str = base64Accum + buf.slice(lastI).toString();
+
+        var canBeDecoded = b64str.length - (b64str.length % 8); // Minimal chunk: 2 quads -> 2x3 bytes -> 3 chars.
+        base64Accum = b64str.slice(canBeDecoded); // The rest will be decoded in future.
+        b64str = b64str.slice(0, canBeDecoded);
+
+        res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
+    }
+
+    this.inBase64 = inBase64;
+    this.base64Accum = base64Accum;
+
+    return res;
+}
+
+Utf7Decoder.prototype.end = function() {
+    var res = "";
+    if (this.inBase64 && this.base64Accum.length > 0)
+        res = this.iconv.decode(Buffer.from(this.base64Accum, 'base64'), "utf16-be");
+
+    this.inBase64 = false;
+    this.base64Accum = '';
+    return res;
+}
+
+
+// UTF-7-IMAP codec.
+// RFC3501 Sec. 5.1.3 Modified UTF-7 (http://tools.ietf.org/html/rfc3501#section-5.1.3)
+// Differences:
+//  * Base64 part is started by "&" instead of "+"
+//  * Direct characters are 0x20-0x7E, except "&" (0x26)
+//  * In Base64, "," is used instead of "/"
+//  * Base64 must not be used to represent direct characters.
+//  * No implicit shift back from Base64 (should always end with '-')
+//  * String must end in non-shifted position.
+//  * "-&" while in base64 is not allowed.
+
+
+exports.utf7imap = Utf7IMAPCodec;
+function Utf7IMAPCodec(codecOptions, iconv) {
+    this.iconv = iconv;
+};
+
+Utf7IMAPCodec.prototype.encoder = Utf7IMAPEncoder;
+Utf7IMAPCodec.prototype.decoder = Utf7IMAPDecoder;
+Utf7IMAPCodec.prototype.bomAware = true;
+
+
+// -- Encoding
+
+function Utf7IMAPEncoder(options, codec) {
+    this.iconv = codec.iconv;
+    this.inBase64 = false;
+    this.base64Accum = Buffer.alloc(6);
+    this.base64AccumIdx = 0;
+}
+
+Utf7IMAPEncoder.prototype.write = function(str) {
+    var inBase64 = this.inBase64,
+        base64Accum = this.base64Accum,
+        base64AccumIdx = this.base64AccumIdx,
+        buf = Buffer.alloc(str.length*5 + 10), bufIdx = 0;
+
+    for (var i = 0; i < str.length; i++) {
+        var uChar = str.charCodeAt(i);
+        if (0x20 <= uChar && uChar <= 0x7E) { // Direct character or '&'.
+            if (inBase64) {
+                if (base64AccumIdx > 0) {
+                    bufIdx += buf.write(base64Accum.slice(0, base64AccumIdx).toString('base64').replace(/\//g, ',').replace(/=+$/, ''), bufIdx);
+                    base64AccumIdx = 0;
+                }
+
+                buf[bufIdx++] = minusChar; // Write '-', then go to direct mode.
+                inBase64 = false;
+            }
+
+            if (!inBase64) {
+                buf[bufIdx++] = uChar; // Write direct character
+
+                if (uChar === andChar)  // Ampersand -> '&-'
+                    buf[bufIdx++] = minusChar;
+            }
+
+        } else { // Non-direct character
+            if (!inBase64) {
+                buf[bufIdx++] = andChar; // Write '&', then go to base64 mode.
+                inBase64 = true;
+            }
+            if (inBase64) {
+                base64Accum[base64AccumIdx++] = uChar >> 8;
+                base64Accum[base64AccumIdx++] = uChar & 0xFF;
+
+                if (base64AccumIdx == base64Accum.length) {
+                    bufIdx += buf.write(base64Accum.toString('base64').replace(/\//g, ','), bufIdx);
+                    base64AccumIdx = 0;
+                }
+            }
+        }
+    }
+
+    this.inBase64 = inBase64;
+    this.base64AccumIdx = base64AccumIdx;
+
+    return buf.slice(0, bufIdx);
+}
+
+Utf7IMAPEncoder.prototype.end = function() {
+    var buf = Buffer.alloc(10), bufIdx = 0;
+    if (this.inBase64) {
+        if (this.base64AccumIdx > 0) {
+            bufIdx += buf.write(this.base64Accum.slice(0, this.base64AccumIdx).toString('base64').replace(/\//g, ',').replace(/=+$/, ''), bufIdx);
+            this.base64AccumIdx = 0;
+        }
+
+        buf[bufIdx++] = minusChar; // Write '-', then go to direct mode.
+        this.inBase64 = false;
+    }
+
+    return buf.slice(0, bufIdx);
+}
+
+
+// -- Decoding
+
+function Utf7IMAPDecoder(options, codec) {
+    this.iconv = codec.iconv;
+    this.inBase64 = false;
+    this.base64Accum = '';
+}
+
+var base64IMAPChars = base64Chars.slice();
+base64IMAPChars[','.charCodeAt(0)] = true;
+
+Utf7IMAPDecoder.prototype.write = function(buf) {
+    var res = "", lastI = 0,
+        inBase64 = this.inBase64,
+        base64Accum = this.base64Accum;
+
+    // The decoder is more involved as we must handle chunks in stream.
+    // It is forgiving, closer to standard UTF-7 (for example, '-' is optional at the end).
+
+    for (var i = 0; i < buf.length; i++) {
+        if (!inBase64) { // We're in direct mode.
+            // Write direct chars until '&'
+            if (buf[i] == andChar) {
+                res += this.iconv.decode(buf.slice(lastI, i), "ascii"); // Write direct chars.
+                lastI = i+1;
+                inBase64 = true;
+            }
+        } else { // We decode base64.
+            if (!base64IMAPChars[buf[i]]) { // Base64 ended.
+                if (i == lastI && buf[i] == minusChar) { // "&-" -> "&"
+                    res += "&";
+                } else {
+                    var b64str = base64Accum + buf.slice(lastI, i).toString().replace(/,/g, '/');
+                    res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
+                }
+
+                if (buf[i] != minusChar) // Minus may be absorbed after base64.
+                    i--;
+
+                lastI = i+1;
+                inBase64 = false;
+                base64Accum = '';
+            }
+        }
+    }
+
+    if (!inBase64) {
+        res += this.iconv.decode(buf.slice(lastI), "ascii"); // Write direct chars.
+    } else {
+        var b64str = base64Accum + buf.slice(lastI).toString().replace(/,/g, '/');
+
+        var canBeDecoded = b64str.length - (b64str.length % 8); // Minimal chunk: 2 quads -> 2x3 bytes -> 3 chars.
+        base64Accum = b64str.slice(canBeDecoded); // The rest will be decoded in future.
+        b64str = b64str.slice(0, canBeDecoded);
+
+        res += this.iconv.decode(Buffer.from(b64str, 'base64'), "utf16-be");
+    }
+
+    this.inBase64 = inBase64;
+    this.base64Accum = base64Accum;
+
+    return res;
+}
+
+Utf7IMAPDecoder.prototype.end = function() {
+    var res = "";
+    if (this.inBase64 && this.base64Accum.length > 0)
+        res = this.iconv.decode(Buffer.from(this.base64Accum, 'base64'), "utf16-be");
+
+    this.inBase64 = false;
+    this.base64Accum = '';
+    return res;
+}
+
+
diff --git a/server/node_modules/iconv-lite/lib/bom-handling.js b/server/node_modules/iconv-lite/lib/bom-handling.js
new file mode 100644
index 0000000..1050872
--- /dev/null
+++ b/server/node_modules/iconv-lite/lib/bom-handling.js
@@ -0,0 +1,52 @@
+"use strict";
+
+var BOMChar = '\uFEFF';
+
+exports.PrependBOM = PrependBOMWrapper
+function PrependBOMWrapper(encoder, options) {
+    this.encoder = encoder;
+    this.addBOM = true;
+}
+
+PrependBOMWrapper.prototype.write = function(str) {
+    if (this.addBOM) {
+        str = BOMChar + str;
+        this.addBOM = false;
+    }
+
+    return this.encoder.write(str);
+}
+
+PrependBOMWrapper.prototype.end = function() {
+    return this.encoder.end();
+}
+
+
+//------------------------------------------------------------------------------
+
+exports.StripBOM = StripBOMWrapper;
+function StripBOMWrapper(decoder, options) {
+    this.decoder = decoder;
+    this.pass = false;
+    this.options = options || {};
+}
+
+StripBOMWrapper.prototype.write = function(buf) {
+    var res = this.decoder.write(buf);
+    if (this.pass || !res)
+        return res;
+
+    if (res[0] === BOMChar) {
+        res = res.slice(1);
+        if (typeof this.options.stripBOM === 'function')
+            this.options.stripBOM();
+    }
+
+    this.pass = true;
+    return res;
+}
+
+StripBOMWrapper.prototype.end = function() {
+    return this.decoder.end();
+}
+
diff --git a/server/node_modules/iconv-lite/lib/extend-node.js b/server/node_modules/iconv-lite/lib/extend-node.js
new file mode 100644
index 0000000..87f5394
--- /dev/null
+++ b/server/node_modules/iconv-lite/lib/extend-node.js
@@ -0,0 +1,217 @@
+"use strict";
+var Buffer = require("buffer").Buffer;
+// Note: not polyfilled with safer-buffer on a purpose, as overrides Buffer
+
+// == Extend Node primitives to use iconv-lite =================================
+
+module.exports = function (iconv) {
+    var original = undefined; // Place to keep original methods.
+
+    // Node authors rewrote Buffer internals to make it compatible with
+    // Uint8Array and we cannot patch key functions since then.
+    // Note: this does use older Buffer API on a purpose
+    iconv.supportsNodeEncodingsExtension = !(Buffer.from || new Buffer(0) instanceof Uint8Array);
+
+    iconv.extendNodeEncodings = function extendNodeEncodings() {
+        if (original) return;
+        original = {};
+
+        if (!iconv.supportsNodeEncodingsExtension) {
+            console.error("ACTION NEEDED: require('iconv-lite').extendNodeEncodings() is not supported in your version of Node");
+            console.error("See more info at https://github.com/ashtuchkin/iconv-lite/wiki/Node-v4-compatibility");
+            return;
+        }
+
+        var nodeNativeEncodings = {
+            'hex': true, 'utf8': true, 'utf-8': true, 'ascii': true, 'binary': true, 
+            'base64': true, 'ucs2': true, 'ucs-2': true, 'utf16le': true, 'utf-16le': true,
+        };
+
+        Buffer.isNativeEncoding = function(enc) {
+            return enc && nodeNativeEncodings[enc.toLowerCase()];
+        }
+
+        // -- SlowBuffer -----------------------------------------------------------
+        var SlowBuffer = require('buffer').SlowBuffer;
+
+        original.SlowBufferToString = SlowBuffer.prototype.toString;
+        SlowBuffer.prototype.toString = function(encoding, start, end) {
+            encoding = String(encoding || 'utf8').toLowerCase();
+
+            // Use native conversion when possible
+            if (Buffer.isNativeEncoding(encoding))
+                return original.SlowBufferToString.call(this, encoding, start, end);
+
+            // Otherwise, use our decoding method.
+            if (typeof start == 'undefined') start = 0;
+            if (typeof end == 'undefined') end = this.length;
+            return iconv.decode(this.slice(start, end), encoding);
+        }
+
+        original.SlowBufferWrite = SlowBuffer.prototype.write;
+        SlowBuffer.prototype.write = function(string, offset, length, encoding) {
+            // Support both (string, offset, length, encoding)
+            // and the legacy (string, encoding, offset, length)
+            if (isFinite(offset)) {
+                if (!isFinite(length)) {
+                    encoding = length;
+                    length = undefined;
+                }
+            } else {  // legacy
+                var swap = encoding;
+                encoding = offset;
+                offset = length;
+                length = swap;
+            }
+
+            offset = +offset || 0;
+            var remaining = this.length - offset;
+            if (!length) {
+                length = remaining;
+            } else {
+                length = +length;
+                if (length > remaining) {
+                    length = remaining;
+                }
+            }
+            encoding = String(encoding || 'utf8').toLowerCase();
+
+            // Use native conversion when possible
+            if (Buffer.isNativeEncoding(encoding))
+                return original.SlowBufferWrite.call(this, string, offset, length, encoding);
+
+            if (string.length > 0 && (length < 0 || offset < 0))
+                throw new RangeError('attempt to write beyond buffer bounds');
+
+            // Otherwise, use our encoding method.
+            var buf = iconv.encode(string, encoding);
+            if (buf.length < length) length = buf.length;
+            buf.copy(this, offset, 0, length);
+            return length;
+        }
+
+        // -- Buffer ---------------------------------------------------------------
+
+        original.BufferIsEncoding = Buffer.isEncoding;
+        Buffer.isEncoding = function(encoding) {
+            return Buffer.isNativeEncoding(encoding) || iconv.encodingExists(encoding);
+        }
+
+        original.BufferByteLength = Buffer.byteLength;
+        Buffer.byteLength = SlowBuffer.byteLength = function(str, encoding) {
+            encoding = String(encoding || 'utf8').toLowerCase();
+
+            // Use native conversion when possible
+            if (Buffer.isNativeEncoding(encoding))
+                return original.BufferByteLength.call(this, str, encoding);
+
+            // Slow, I know, but we don't have a better way yet.
+            return iconv.encode(str, encoding).length;
+        }
+
+        original.BufferToString = Buffer.prototype.toString;
+        Buffer.prototype.toString = function(encoding, start, end) {
+            encoding = String(encoding || 'utf8').toLowerCase();
+
+            // Use native conversion when possible
+            if (Buffer.isNativeEncoding(encoding))
+                return original.BufferToString.call(this, encoding, start, end);
+
+            // Otherwise, use our decoding method.
+            if (typeof start == 'undefined') start = 0;
+            if (typeof end == 'undefined') end = this.length;
+            return iconv.decode(this.slice(start, end), encoding);
+        }
+
+        original.BufferWrite = Buffer.prototype.write;
+        Buffer.prototype.write = function(string, offset, length, encoding) {
+            var _offset = offset, _length = length, _encoding = encoding;
+            // Support both (string, offset, length, encoding)
+            // and the legacy (string, encoding, offset, length)
+            if (isFinite(offset)) {
+                if (!isFinite(length)) {
+                    encoding = length;
+                    length = undefined;
+                }
+            } else {  // legacy
+                var swap = encoding;
+                encoding = offset;
+                offset = length;
+                length = swap;
+            }
+
+            encoding = String(encoding || 'utf8').toLowerCase();
+
+            // Use native conversion when possible
+            if (Buffer.isNativeEncoding(encoding))
+                return original.BufferWrite.call(this, string, _offset, _length, _encoding);
+
+            offset = +offset || 0;
+            var remaining = this.length - offset;
+            if (!length) {
+                length = remaining;
+            } else {
+                length = +length;
+                if (length > remaining) {
+                    length = remaining;
+                }
+            }
+
+            if (string.length > 0 && (length < 0 || offset < 0))
+                throw new RangeError('attempt to write beyond buffer bounds');
+
+            // Otherwise, use our encoding method.
+            var buf = iconv.encode(string, encoding);
+            if (buf.length < length) length = buf.length;
+            buf.copy(this, offset, 0, length);
+            return length;
+
+            // TODO: Set _charsWritten.
+        }
+
+
+        // -- Readable -------------------------------------------------------------
+        if (iconv.supportsStreams) {
+            var Readable = require('stream').Readable;
+
+            original.ReadableSetEncoding = Readable.prototype.setEncoding;
+            Readable.prototype.setEncoding = function setEncoding(enc, options) {
+                // Use our own decoder, it has the same interface.
+                // We cannot use original function as it doesn't handle BOM-s.
+                this._readableState.decoder = iconv.getDecoder(enc, options);
+                this._readableState.encoding = enc;
+            }
+
+            Readable.prototype.collect = iconv._collect;
+        }
+    }
+
+    // Remove iconv-lite Node primitive extensions.
+    iconv.undoExtendNodeEncodings = function undoExtendNodeEncodings() {
+        if (!iconv.supportsNodeEncodingsExtension)
+            return;
+        if (!original)
+            throw new Error("require('iconv-lite').undoExtendNodeEncodings(): Nothing to undo; extendNodeEncodings() is not called.")
+
+        delete Buffer.isNativeEncoding;
+
+        var SlowBuffer = require('buffer').SlowBuffer;
+
+        SlowBuffer.prototype.toString = original.SlowBufferToString;
+        SlowBuffer.prototype.write = original.SlowBufferWrite;
+
+        Buffer.isEncoding = original.BufferIsEncoding;
+        Buffer.byteLength = original.BufferByteLength;
+        Buffer.prototype.toString = original.BufferToString;
+        Buffer.prototype.write = original.BufferWrite;
+
+        if (iconv.supportsStreams) {
+            var Readable = require('stream').Readable;
+
+            Readable.prototype.setEncoding = original.ReadableSetEncoding;
+            delete Readable.prototype.collect;
+        }
+
+        original = undefined;
+    }
+}
diff --git a/server/node_modules/iconv-lite/lib/index.d.ts b/server/node_modules/iconv-lite/lib/index.d.ts
new file mode 100644
index 0000000..0547eb3
--- /dev/null
+++ b/server/node_modules/iconv-lite/lib/index.d.ts
@@ -0,0 +1,24 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License.
+ *  REQUIREMENT: This definition is dependent on the @types/node definition.
+ *  Install with `npm install @types/node --save-dev`
+ *--------------------------------------------------------------------------------------------*/
+
+declare module 'iconv-lite' {
+	export function decode(buffer: Buffer, encoding: string, options?: Options): string;
+
+	export function encode(content: string, encoding: string, options?: Options): Buffer;
+
+	export function encodingExists(encoding: string): boolean;
+
+	export function decodeStream(encoding: string, options?: Options): NodeJS.ReadWriteStream;
+
+	export function encodeStream(encoding: string, options?: Options): NodeJS.ReadWriteStream;
+}
+
+export interface Options {
+    stripBOM?: boolean;
+    addBOM?: boolean;
+    defaultEncoding?: string;
+}
diff --git a/server/node_modules/iconv-lite/lib/index.js b/server/node_modules/iconv-lite/lib/index.js
new file mode 100644
index 0000000..5391919
--- /dev/null
+++ b/server/node_modules/iconv-lite/lib/index.js
@@ -0,0 +1,153 @@
+"use strict";
+
+// Some environments don't have global Buffer (e.g. React Native).
+// Solution would be installing npm modules "buffer" and "stream" explicitly.
+var Buffer = require("safer-buffer").Buffer;
+
+var bomHandling = require("./bom-handling"),
+    iconv = module.exports;
+
+// All codecs and aliases are kept here, keyed by encoding name/alias.
+// They are lazy loaded in `iconv.getCodec` from `encodings/index.js`.
+iconv.encodings = null;
+
+// Characters emitted in case of error.
+iconv.defaultCharUnicode = '�';
+iconv.defaultCharSingleByte = '?';
+
+// Public API.
+iconv.encode = function encode(str, encoding, options) {
+    str = "" + (str || ""); // Ensure string.
+
+    var encoder = iconv.getEncoder(encoding, options);
+
+    var res = encoder.write(str);
+    var trail = encoder.end();
+    
+    return (trail && trail.length > 0) ? Buffer.concat([res, trail]) : res;
+}
+
+iconv.decode = function decode(buf, encoding, options) {
+    if (typeof buf === 'string') {
+        if (!iconv.skipDecodeWarning) {
+            console.error('Iconv-lite warning: decode()-ing strings is deprecated. Refer to https://github.com/ashtuchkin/iconv-lite/wiki/Use-Buffers-when-decoding');
+            iconv.skipDecodeWarning = true;
+        }
+
+        buf = Buffer.from("" + (buf || ""), "binary"); // Ensure buffer.
+    }
+
+    var decoder = iconv.getDecoder(encoding, options);
+
+    var res = decoder.write(buf);
+    var trail = decoder.end();
+
+    return trail ? (res + trail) : res;
+}
+
+iconv.encodingExists = function encodingExists(enc) {
+    try {
+        iconv.getCodec(enc);
+        return true;
+    } catch (e) {
+        return false;
+    }
+}
+
+// Legacy aliases to convert functions
+iconv.toEncoding = iconv.encode;
+iconv.fromEncoding = iconv.decode;
+
+// Search for a codec in iconv.encodings. Cache codec data in iconv._codecDataCache.
+iconv._codecDataCache = {};
+iconv.getCodec = function getCodec(encoding) {
+    if (!iconv.encodings)
+        iconv.encodings = require("../encodings"); // Lazy load all encoding definitions.
+    
+    // Canonicalize encoding name: strip all non-alphanumeric chars and appended year.
+    var enc = iconv._canonicalizeEncoding(encoding);
+
+    // Traverse iconv.encodings to find actual codec.
+    var codecOptions = {};
+    while (true) {
+        var codec = iconv._codecDataCache[enc];
+        if (codec)
+            return codec;
+
+        var codecDef = iconv.encodings[enc];
+
+        switch (typeof codecDef) {
+            case "string": // Direct alias to other encoding.
+                enc = codecDef;
+                break;
+
+            case "object": // Alias with options. Can be layered.
+                for (var key in codecDef)
+                    codecOptions[key] = codecDef[key];
+
+                if (!codecOptions.encodingName)
+                    codecOptions.encodingName = enc;
+                
+                enc = codecDef.type;
+                break;
+
+            case "function": // Codec itself.
+                if (!codecOptions.encodingName)
+                    codecOptions.encodingName = enc;
+
+                // The codec function must load all tables and return object with .encoder and .decoder methods.
+                // It'll be called only once (for each different options object).
+                codec = new codecDef(codecOptions, iconv);
+
+                iconv._codecDataCache[codecOptions.encodingName] = codec; // Save it to be reused later.
+                return codec;
+
+            default:
+                throw new Error("Encoding not recognized: '" + encoding + "' (searched as: '"+enc+"')");
+        }
+    }
+}
+
+iconv._canonicalizeEncoding = function(encoding) {
+    // Canonicalize encoding name: strip all non-alphanumeric chars and appended year.
+    return (''+encoding).toLowerCase().replace(/:\d{4}$|[^0-9a-z]/g, "");
+}
+
+iconv.getEncoder = function getEncoder(encoding, options) {
+    var codec = iconv.getCodec(encoding),
+        encoder = new codec.encoder(options, codec);
+
+    if (codec.bomAware && options && options.addBOM)
+        encoder = new bomHandling.PrependBOM(encoder, options);
+
+    return encoder;
+}
+
+iconv.getDecoder = function getDecoder(encoding, options) {
+    var codec = iconv.getCodec(encoding),
+        decoder = new codec.decoder(options, codec);
+
+    if (codec.bomAware && !(options && options.stripBOM === false))
+        decoder = new bomHandling.StripBOM(decoder, options);
+
+    return decoder;
+}
+
+
+// Load extensions in Node. All of them are omitted in Browserify build via 'browser' field in package.json.
+var nodeVer = typeof process !== 'undefined' && process.versions && process.versions.node;
+if (nodeVer) {
+
+    // Load streaming support in Node v0.10+
+    var nodeVerArr = nodeVer.split(".").map(Number);
+    if (nodeVerArr[0] > 0 || nodeVerArr[1] >= 10) {
+        require("./streams")(iconv);
+    }
+
+    // Load Node primitive extensions.
+    require("./extend-node")(iconv);
+}
+
+if ("Ā" != "\u0100") {
+    console.error("iconv-lite warning: javascript files use encoding different from utf-8. See https://github.com/ashtuchkin/iconv-lite/wiki/Javascript-source-file-encodings for more info.");
+}
diff --git a/server/node_modules/iconv-lite/lib/streams.js b/server/node_modules/iconv-lite/lib/streams.js
new file mode 100644
index 0000000..4409552
--- /dev/null
+++ b/server/node_modules/iconv-lite/lib/streams.js
@@ -0,0 +1,121 @@
+"use strict";
+
+var Buffer = require("buffer").Buffer,
+    Transform = require("stream").Transform;
+
+
+// == Exports ==================================================================
+module.exports = function(iconv) {
+    
+    // Additional Public API.
+    iconv.encodeStream = function encodeStream(encoding, options) {
+        return new IconvLiteEncoderStream(iconv.getEncoder(encoding, options), options);
+    }
+
+    iconv.decodeStream = function decodeStream(encoding, options) {
+        return new IconvLiteDecoderStream(iconv.getDecoder(encoding, options), options);
+    }
+
+    iconv.supportsStreams = true;
+
+
+    // Not published yet.
+    iconv.IconvLiteEncoderStream = IconvLiteEncoderStream;
+    iconv.IconvLiteDecoderStream = IconvLiteDecoderStream;
+    iconv._collect = IconvLiteDecoderStream.prototype.collect;
+};
+
+
+// == Encoder stream =======================================================
+function IconvLiteEncoderStream(conv, options) {
+    this.conv = conv;
+    options = options || {};
+    options.decodeStrings = false; // We accept only strings, so we don't need to decode them.
+    Transform.call(this, options);
+}
+
+IconvLiteEncoderStream.prototype = Object.create(Transform.prototype, {
+    constructor: { value: IconvLiteEncoderStream }
+});
+
+IconvLiteEncoderStream.prototype._transform = function(chunk, encoding, done) {
+    if (typeof chunk != 'string')
+        return done(new Error("Iconv encoding stream needs strings as its input."));
+    try {
+        var res = this.conv.write(chunk);
+        if (res && res.length) this.push(res);
+        done();
+    }
+    catch (e) {
+        done(e);
+    }
+}
+
+IconvLiteEncoderStream.prototype._flush = function(done) {
+    try {
+        var res = this.conv.end();
+        if (res && res.length) this.push(res);
+        done();
+    }
+    catch (e) {
+        done(e);
+    }
+}
+
+IconvLiteEncoderStream.prototype.collect = function(cb) {
+    var chunks = [];
+    this.on('error', cb);
+    this.on('data', function(chunk) { chunks.push(chunk); });
+    this.on('end', function() {
+        cb(null, Buffer.concat(chunks));
+    });
+    return this;
+}
+
+
+// == Decoder stream =======================================================
+function IconvLiteDecoderStream(conv, options) {
+    this.conv = conv;
+    options = options || {};
+    options.encoding = this.encoding = 'utf8'; // We output strings.
+    Transform.call(this, options);
+}
+
+IconvLiteDecoderStream.prototype = Object.create(Transform.prototype, {
+    constructor: { value: IconvLiteDecoderStream }
+});
+
+IconvLiteDecoderStream.prototype._transform = function(chunk, encoding, done) {
+    if (!Buffer.isBuffer(chunk))
+        return done(new Error("Iconv decoding stream needs buffers as its input."));
+    try {
+        var res = this.conv.write(chunk);
+        if (res && res.length) this.push(res, this.encoding);
+        done();
+    }
+    catch (e) {
+        done(e);
+    }
+}
+
+IconvLiteDecoderStream.prototype._flush = function(done) {
+    try {
+        var res = this.conv.end();
+        if (res && res.length) this.push(res, this.encoding);                
+        done();
+    }
+    catch (e) {
+        done(e);
+    }
+}
+
+IconvLiteDecoderStream.prototype.collect = function(cb) {
+    var res = '';
+    this.on('error', cb);
+    this.on('data', function(chunk) { res += chunk; });
+    this.on('end', function() {
+        cb(null, res);
+    });
+    return this;
+}
+
diff --git a/server/node_modules/iconv-lite/package.json b/server/node_modules/iconv-lite/package.json
new file mode 100644
index 0000000..a7c74fc
--- /dev/null
+++ b/server/node_modules/iconv-lite/package.json
@@ -0,0 +1,46 @@
+{
+    "name": "iconv-lite",
+    "description": "Convert character encodings in pure javascript.",
+    "version": "0.4.24",
+    "license": "MIT",
+    "keywords": [
+        "iconv",
+        "convert",
+        "charset",
+        "icu"
+    ],
+    "author": "Alexander Shtuchkin <ashtuchkin@gmail.com>",
+    "main": "./lib/index.js",
+    "typings": "./lib/index.d.ts",
+    "homepage": "https://github.com/ashtuchkin/iconv-lite",
+    "bugs": "https://github.com/ashtuchkin/iconv-lite/issues",
+    "repository": {
+        "type": "git",
+        "url": "git://github.com/ashtuchkin/iconv-lite.git"
+    },
+    "engines": {
+        "node": ">=0.10.0"
+    },
+    "scripts": {
+        "coverage": "istanbul cover _mocha -- --grep .",
+        "coverage-open": "open coverage/lcov-report/index.html",
+        "test": "mocha --reporter spec --grep ."
+    },
+    "browser": {
+        "./lib/extend-node": false,
+        "./lib/streams": false
+    },
+    "devDependencies": {
+        "mocha": "^3.1.0",
+        "request": "~2.87.0",
+        "unorm": "*",
+        "errto": "*",
+        "async": "*",
+        "istanbul": "*",
+        "semver": "*",
+        "iconv": "*"
+    },
+    "dependencies": {
+        "safer-buffer": ">= 2.1.2 < 3"
+    }
+}
diff --git a/server/node_modules/ieee754/LICENSE b/server/node_modules/ieee754/LICENSE
new file mode 100644
index 0000000..5aac82c
--- /dev/null
+++ b/server/node_modules/ieee754/LICENSE
@@ -0,0 +1,11 @@
+Copyright 2008 Fair Oaks Labs, Inc.
+
+Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/server/node_modules/ieee754/README.md b/server/node_modules/ieee754/README.md
new file mode 100644
index 0000000..cb7527b
--- /dev/null
+++ b/server/node_modules/ieee754/README.md
@@ -0,0 +1,51 @@
+# ieee754 [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![downloads][downloads-image]][downloads-url] [![javascript style guide][standard-image]][standard-url]
+
+[travis-image]: https://img.shields.io/travis/feross/ieee754/master.svg
+[travis-url]: https://travis-ci.org/feross/ieee754
+[npm-image]: https://img.shields.io/npm/v/ieee754.svg
+[npm-url]: https://npmjs.org/package/ieee754
+[downloads-image]: https://img.shields.io/npm/dm/ieee754.svg
+[downloads-url]: https://npmjs.org/package/ieee754
+[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
+[standard-url]: https://standardjs.com
+
+[![saucelabs][saucelabs-image]][saucelabs-url]
+
+[saucelabs-image]: https://saucelabs.com/browser-matrix/ieee754.svg
+[saucelabs-url]: https://saucelabs.com/u/ieee754
+
+### Read/write IEEE754 floating point numbers from/to a Buffer or array-like object.
+
+## install
+
+```
+npm install ieee754
+```
+
+## methods
+
+`var ieee754 = require('ieee754')`
+
+The `ieee754` object has the following functions:
+
+```
+ieee754.read = function (buffer, offset, isLE, mLen, nBytes)
+ieee754.write = function (buffer, value, offset, isLE, mLen, nBytes)
+```
+
+The arguments mean the following:
+
+- buffer = the buffer
+- offset = offset into the buffer
+- value = value to set (only for `write`)
+- isLe = is little endian?
+- mLen = mantissa length
+- nBytes = number of bytes
+
+## what is ieee754?
+
+The IEEE Standard for Floating-Point Arithmetic (IEEE 754) is a technical standard for floating-point computation. [Read more](http://en.wikipedia.org/wiki/IEEE_floating_point).
+
+## license
+
+BSD 3 Clause. Copyright (c) 2008, Fair Oaks Labs, Inc.
diff --git a/server/node_modules/ieee754/index.d.ts b/server/node_modules/ieee754/index.d.ts
new file mode 100644
index 0000000..f1e4354
--- /dev/null
+++ b/server/node_modules/ieee754/index.d.ts
@@ -0,0 +1,10 @@
+declare namespace ieee754 {
+    export function read(
+        buffer: Uint8Array, offset: number, isLE: boolean, mLen: number,
+        nBytes: number): number;
+    export function write(
+        buffer: Uint8Array, value: number, offset: number, isLE: boolean,
+        mLen: number, nBytes: number): void;
+  }
+  
+  export = ieee754;
\ No newline at end of file
diff --git a/server/node_modules/ieee754/index.js b/server/node_modules/ieee754/index.js
new file mode 100644
index 0000000..81d26c3
--- /dev/null
+++ b/server/node_modules/ieee754/index.js
@@ -0,0 +1,85 @@
+/*! ieee754. BSD-3-Clause License. Feross Aboukhadijeh <https://feross.org/opensource> */
+exports.read = function (buffer, offset, isLE, mLen, nBytes) {
+  var e, m
+  var eLen = (nBytes * 8) - mLen - 1
+  var eMax = (1 << eLen) - 1
+  var eBias = eMax >> 1
+  var nBits = -7
+  var i = isLE ? (nBytes - 1) : 0
+  var d = isLE ? -1 : 1
+  var s = buffer[offset + i]
+
+  i += d
+
+  e = s & ((1 << (-nBits)) - 1)
+  s >>= (-nBits)
+  nBits += eLen
+  for (; nBits > 0; e = (e * 256) + buffer[offset + i], i += d, nBits -= 8) {}
+
+  m = e & ((1 << (-nBits)) - 1)
+  e >>= (-nBits)
+  nBits += mLen
+  for (; nBits > 0; m = (m * 256) + buffer[offset + i], i += d, nBits -= 8) {}
+
+  if (e === 0) {
+    e = 1 - eBias
+  } else if (e === eMax) {
+    return m ? NaN : ((s ? -1 : 1) * Infinity)
+  } else {
+    m = m + Math.pow(2, mLen)
+    e = e - eBias
+  }
+  return (s ? -1 : 1) * m * Math.pow(2, e - mLen)
+}
+
+exports.write = function (buffer, value, offset, isLE, mLen, nBytes) {
+  var e, m, c
+  var eLen = (nBytes * 8) - mLen - 1
+  var eMax = (1 << eLen) - 1
+  var eBias = eMax >> 1
+  var rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0)
+  var i = isLE ? 0 : (nBytes - 1)
+  var d = isLE ? 1 : -1
+  var s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0
+
+  value = Math.abs(value)
+
+  if (isNaN(value) || value === Infinity) {
+    m = isNaN(value) ? 1 : 0
+    e = eMax
+  } else {
+    e = Math.floor(Math.log(value) / Math.LN2)
+    if (value * (c = Math.pow(2, -e)) < 1) {
+      e--
+      c *= 2
+    }
+    if (e + eBias >= 1) {
+      value += rt / c
+    } else {
+      value += rt * Math.pow(2, 1 - eBias)
+    }
+    if (value * c >= 2) {
+      e++
+      c /= 2
+    }
+
+    if (e + eBias >= eMax) {
+      m = 0
+      e = eMax
+    } else if (e + eBias >= 1) {
+      m = ((value * c) - 1) * Math.pow(2, mLen)
+      e = e + eBias
+    } else {
+      m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen)
+      e = 0
+    }
+  }
+
+  for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8) {}
+
+  e = (e << mLen) | m
+  eLen += mLen
+  for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8) {}
+
+  buffer[offset + i - d] |= s * 128
+}
diff --git a/server/node_modules/ieee754/package.json b/server/node_modules/ieee754/package.json
new file mode 100644
index 0000000..7b23851
--- /dev/null
+++ b/server/node_modules/ieee754/package.json
@@ -0,0 +1,52 @@
+{
+  "name": "ieee754",
+  "description": "Read/write IEEE754 floating point numbers from/to a Buffer or array-like object",
+  "version": "1.2.1",
+  "author": {
+    "name": "Feross Aboukhadijeh",
+    "email": "feross@feross.org",
+    "url": "https://feross.org"
+  },
+  "contributors": [
+    "Romain Beauxis <toots@rastageeks.org>"
+  ],
+  "devDependencies": {
+    "airtap": "^3.0.0",
+    "standard": "*",
+    "tape": "^5.0.1"
+  },
+  "keywords": [
+    "IEEE 754",
+    "buffer",
+    "convert",
+    "floating point",
+    "ieee754"
+  ],
+  "license": "BSD-3-Clause",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/feross/ieee754.git"
+  },
+  "scripts": {
+    "test": "standard && npm run test-node && npm run test-browser",
+    "test-browser": "airtap -- test/*.js",
+    "test-browser-local": "airtap --local -- test/*.js",
+    "test-node": "tape test/*.js"
+  },
+  "funding": [
+    {
+      "type": "github",
+      "url": "https://github.com/sponsors/feross"
+    },
+    {
+      "type": "patreon",
+      "url": "https://www.patreon.com/feross"
+    },
+    {
+      "type": "consulting",
+      "url": "https://feross.org/support"
+    }
+  ]
+}
diff --git a/server/node_modules/imurmurhash/README.md b/server/node_modules/imurmurhash/README.md
new file mode 100644
index 0000000..f35b20a
--- /dev/null
+++ b/server/node_modules/imurmurhash/README.md
@@ -0,0 +1,122 @@
+iMurmurHash.js
+==============
+
+An incremental implementation of the MurmurHash3 (32-bit) hashing algorithm for JavaScript based on [Gary Court's implementation](https://github.com/garycourt/murmurhash-js) with [kazuyukitanimura's modifications](https://github.com/kazuyukitanimura/murmurhash-js).
+
+This version works significantly faster than the non-incremental version if you need to hash many small strings into a single hash, since string concatenation (to build the single string to pass the non-incremental version) is fairly costly. In one case tested, using the incremental version was about 50% faster than concatenating 5-10 strings and then hashing.
+
+Installation
+------------
+
+To use iMurmurHash in the browser, [download the latest version](https://raw.github.com/jensyt/imurmurhash-js/master/imurmurhash.min.js) and include it as a script on your site.
+
+```html
+<script type="text/javascript" src="/scripts/imurmurhash.min.js"></script>
+<script>
+// Your code here, access iMurmurHash using the global object MurmurHash3
+</script>
+```
+
+---
+
+To use iMurmurHash in Node.js, install the module using NPM:
+
+```bash
+npm install imurmurhash
+```
+
+Then simply include it in your scripts:
+
+```javascript
+MurmurHash3 = require('imurmurhash');
+```
+
+Quick Example
+-------------
+
+```javascript
+// Create the initial hash
+var hashState = MurmurHash3('string');
+
+// Incrementally add text
+hashState.hash('more strings');
+hashState.hash('even more strings');
+
+// All calls can be chained if desired
+hashState.hash('and').hash('some').hash('more');
+
+// Get a result
+hashState.result();
+// returns 0xe4ccfe6b
+```
+
+Functions
+---------
+
+### MurmurHash3 ([string], [seed])
+Get a hash state object, optionally initialized with the given _string_ and _seed_. _Seed_ must be a positive integer if provided. Calling this function without the `new` keyword will return a cached state object that has been reset. This is safe to use as long as the object is only used from a single thread and no other hashes are created while operating on this one. If this constraint cannot be met, you can use `new` to create a new state object. For example:
+
+```javascript
+// Use the cached object, calling the function again will return the same
+// object (but reset, so the current state would be lost)
+hashState = MurmurHash3();
+...
+
+// Create a new object that can be safely used however you wish. Calling the
+// function again will simply return a new state object, and no state loss
+// will occur, at the cost of creating more objects.
+hashState = new MurmurHash3();
+```
+
+Both methods can be mixed however you like if you have different use cases.
+
+---
+
+### MurmurHash3.prototype.hash (string)
+Incrementally add _string_ to the hash. This can be called as many times as you want for the hash state object, including after a call to `result()`. Returns `this` so calls can be chained.
+
+---
+
+### MurmurHash3.prototype.result ()
+Get the result of the hash as a 32-bit positive integer. This performs the tail and finalizer portions of the algorithm, but does not store the result in the state object. This means that it is perfectly safe to get results and then continue adding strings via `hash`.
+
+```javascript
+// Do the whole string at once
+MurmurHash3('this is a test string').result();
+// 0x70529328
+
+// Do part of the string, get a result, then the other part
+var m = MurmurHash3('this is a');
+m.result();
+// 0xbfc4f834
+m.hash(' test string').result();
+// 0x70529328 (same as above)
+```
+
+---
+
+### MurmurHash3.prototype.reset ([seed])
+Reset the state object for reuse, optionally using the given _seed_ (defaults to 0 like the constructor). Returns `this` so calls can be chained.
+
+---
+
+License (MIT)
+-------------
+Copyright (c) 2013 Gary Court, Jens Taylor
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/imurmurhash/imurmurhash.js b/server/node_modules/imurmurhash/imurmurhash.js
new file mode 100644
index 0000000..e63146a
--- /dev/null
+++ b/server/node_modules/imurmurhash/imurmurhash.js
@@ -0,0 +1,138 @@
+/**
+ * @preserve
+ * JS Implementation of incremental MurmurHash3 (r150) (as of May 10, 2013)
+ *
+ * @author <a href="mailto:jensyt@gmail.com">Jens Taylor</a>
+ * @see http://github.com/homebrewing/brauhaus-diff
+ * @author <a href="mailto:gary.court@gmail.com">Gary Court</a>
+ * @see http://github.com/garycourt/murmurhash-js
+ * @author <a href="mailto:aappleby@gmail.com">Austin Appleby</a>
+ * @see http://sites.google.com/site/murmurhash/
+ */
+(function(){
+    var cache;
+
+    // Call this function without `new` to use the cached object (good for
+    // single-threaded environments), or with `new` to create a new object.
+    //
+    // @param {string} key A UTF-16 or ASCII string
+    // @param {number} seed An optional positive integer
+    // @return {object} A MurmurHash3 object for incremental hashing
+    function MurmurHash3(key, seed) {
+        var m = this instanceof MurmurHash3 ? this : cache;
+        m.reset(seed)
+        if (typeof key === 'string' && key.length > 0) {
+            m.hash(key);
+        }
+
+        if (m !== this) {
+            return m;
+        }
+    };
+
+    // Incrementally add a string to this hash
+    //
+    // @param {string} key A UTF-16 or ASCII string
+    // @return {object} this
+    MurmurHash3.prototype.hash = function(key) {
+        var h1, k1, i, top, len;
+
+        len = key.length;
+        this.len += len;
+
+        k1 = this.k1;
+        i = 0;
+        switch (this.rem) {
+            case 0: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) : 0;
+            case 1: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) << 8 : 0;
+            case 2: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) << 16 : 0;
+            case 3:
+                k1 ^= len > i ? (key.charCodeAt(i) & 0xff) << 24 : 0;
+                k1 ^= len > i ? (key.charCodeAt(i++) & 0xff00) >> 8 : 0;
+        }
+
+        this.rem = (len + this.rem) & 3; // & 3 is same as % 4
+        len -= this.rem;
+        if (len > 0) {
+            h1 = this.h1;
+            while (1) {
+                k1 = (k1 * 0x2d51 + (k1 & 0xffff) * 0xcc9e0000) & 0xffffffff;
+                k1 = (k1 << 15) | (k1 >>> 17);
+                k1 = (k1 * 0x3593 + (k1 & 0xffff) * 0x1b870000) & 0xffffffff;
+
+                h1 ^= k1;
+                h1 = (h1 << 13) | (h1 >>> 19);
+                h1 = (h1 * 5 + 0xe6546b64) & 0xffffffff;
+
+                if (i >= len) {
+                    break;
+                }
+
+                k1 = ((key.charCodeAt(i++) & 0xffff)) ^
+                     ((key.charCodeAt(i++) & 0xffff) << 8) ^
+                     ((key.charCodeAt(i++) & 0xffff) << 16);
+                top = key.charCodeAt(i++);
+                k1 ^= ((top & 0xff) << 24) ^
+                      ((top & 0xff00) >> 8);
+            }
+
+            k1 = 0;
+            switch (this.rem) {
+                case 3: k1 ^= (key.charCodeAt(i + 2) & 0xffff) << 16;
+                case 2: k1 ^= (key.charCodeAt(i + 1) & 0xffff) << 8;
+                case 1: k1 ^= (key.charCodeAt(i) & 0xffff);
+            }
+
+            this.h1 = h1;
+        }
+
+        this.k1 = k1;
+        return this;
+    };
+
+    // Get the result of this hash
+    //
+    // @return {number} The 32-bit hash
+    MurmurHash3.prototype.result = function() {
+        var k1, h1;
+        
+        k1 = this.k1;
+        h1 = this.h1;
+
+        if (k1 > 0) {
+            k1 = (k1 * 0x2d51 + (k1 & 0xffff) * 0xcc9e0000) & 0xffffffff;
+            k1 = (k1 << 15) | (k1 >>> 17);
+            k1 = (k1 * 0x3593 + (k1 & 0xffff) * 0x1b870000) & 0xffffffff;
+            h1 ^= k1;
+        }
+
+        h1 ^= this.len;
+
+        h1 ^= h1 >>> 16;
+        h1 = (h1 * 0xca6b + (h1 & 0xffff) * 0x85eb0000) & 0xffffffff;
+        h1 ^= h1 >>> 13;
+        h1 = (h1 * 0xae35 + (h1 & 0xffff) * 0xc2b20000) & 0xffffffff;
+        h1 ^= h1 >>> 16;
+
+        return h1 >>> 0;
+    };
+
+    // Reset the hash object for reuse
+    //
+    // @param {number} seed An optional positive integer
+    MurmurHash3.prototype.reset = function(seed) {
+        this.h1 = typeof seed === 'number' ? seed : 0;
+        this.rem = this.k1 = this.len = 0;
+        return this;
+    };
+
+    // A cached object to use. This can be safely used if you're in a single-
+    // threaded environment, otherwise you need to create new hashes to use.
+    cache = new MurmurHash3();
+
+    if (typeof(module) != 'undefined') {
+        module.exports = MurmurHash3;
+    } else {
+        this.MurmurHash3 = MurmurHash3;
+    }
+}());
diff --git a/server/node_modules/imurmurhash/imurmurhash.min.js b/server/node_modules/imurmurhash/imurmurhash.min.js
new file mode 100644
index 0000000..dc0ee88
--- /dev/null
+++ b/server/node_modules/imurmurhash/imurmurhash.min.js
@@ -0,0 +1,12 @@
+/**
+ * @preserve
+ * JS Implementation of incremental MurmurHash3 (r150) (as of May 10, 2013)
+ *
+ * @author <a href="mailto:jensyt@gmail.com">Jens Taylor</a>
+ * @see http://github.com/homebrewing/brauhaus-diff
+ * @author <a href="mailto:gary.court@gmail.com">Gary Court</a>
+ * @see http://github.com/garycourt/murmurhash-js
+ * @author <a href="mailto:aappleby@gmail.com">Austin Appleby</a>
+ * @see http://sites.google.com/site/murmurhash/
+ */
+!function(){function t(h,r){var s=this instanceof t?this:e;return s.reset(r),"string"==typeof h&&h.length>0&&s.hash(h),s!==this?s:void 0}var e;t.prototype.hash=function(t){var e,h,r,s,i;switch(i=t.length,this.len+=i,h=this.k1,r=0,this.rem){case 0:h^=i>r?65535&t.charCodeAt(r++):0;case 1:h^=i>r?(65535&t.charCodeAt(r++))<<8:0;case 2:h^=i>r?(65535&t.charCodeAt(r++))<<16:0;case 3:h^=i>r?(255&t.charCodeAt(r))<<24:0,h^=i>r?(65280&t.charCodeAt(r++))>>8:0}if(this.rem=3&i+this.rem,i-=this.rem,i>0){for(e=this.h1;;){if(h=4294967295&11601*h+3432906752*(65535&h),h=h<<15|h>>>17,h=4294967295&13715*h+461832192*(65535&h),e^=h,e=e<<13|e>>>19,e=4294967295&5*e+3864292196,r>=i)break;h=65535&t.charCodeAt(r++)^(65535&t.charCodeAt(r++))<<8^(65535&t.charCodeAt(r++))<<16,s=t.charCodeAt(r++),h^=(255&s)<<24^(65280&s)>>8}switch(h=0,this.rem){case 3:h^=(65535&t.charCodeAt(r+2))<<16;case 2:h^=(65535&t.charCodeAt(r+1))<<8;case 1:h^=65535&t.charCodeAt(r)}this.h1=e}return this.k1=h,this},t.prototype.result=function(){var t,e;return t=this.k1,e=this.h1,t>0&&(t=4294967295&11601*t+3432906752*(65535&t),t=t<<15|t>>>17,t=4294967295&13715*t+461832192*(65535&t),e^=t),e^=this.len,e^=e>>>16,e=4294967295&51819*e+2246770688*(65535&e),e^=e>>>13,e=4294967295&44597*e+3266445312*(65535&e),e^=e>>>16,e>>>0},t.prototype.reset=function(t){return this.h1="number"==typeof t?t:0,this.rem=this.k1=this.len=0,this},e=new t,"undefined"!=typeof module?module.exports=t:this.MurmurHash3=t}();
\ No newline at end of file
diff --git a/server/node_modules/imurmurhash/package.json b/server/node_modules/imurmurhash/package.json
new file mode 100644
index 0000000..8a93edb
--- /dev/null
+++ b/server/node_modules/imurmurhash/package.json
@@ -0,0 +1,40 @@
+{
+  "name": "imurmurhash",
+  "version": "0.1.4",
+  "description": "An incremental implementation of MurmurHash3",
+  "homepage": "https://github.com/jensyt/imurmurhash-js",
+  "main": "imurmurhash.js",
+  "files": [
+    "imurmurhash.js",
+    "imurmurhash.min.js",
+    "package.json",
+    "README.md"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/jensyt/imurmurhash-js"
+  },
+  "bugs": {
+    "url": "https://github.com/jensyt/imurmurhash-js/issues"
+  },
+  "keywords": [
+    "murmur",
+    "murmurhash",
+    "murmurhash3",
+    "hash",
+    "incremental"
+  ],
+  "author": {
+    "name": "Jens Taylor",
+    "email": "jensyt@gmail.com",
+    "url": "https://github.com/homebrewing"
+  },
+  "license": "MIT",
+  "dependencies": {
+  },
+  "devDependencies": {
+  },
+  "engines": {
+    "node": ">=0.8.19"
+  }
+}
diff --git a/server/node_modules/indent-string/index.d.ts b/server/node_modules/indent-string/index.d.ts
new file mode 100644
index 0000000..1185231
--- /dev/null
+++ b/server/node_modules/indent-string/index.d.ts
@@ -0,0 +1,42 @@
+declare namespace indentString {
+	interface Options {
+		/**
+		The string to use for the indent.
+
+		@default ' '
+		*/
+		readonly indent?: string;
+
+		/**
+		Also indent empty lines.
+
+		@default false
+		*/
+		readonly includeEmptyLines?: boolean;
+	}
+}
+
+/**
+Indent each line in a string.
+
+@param string - The string to indent.
+@param count - How many times you want `options.indent` repeated. Default: `1`.
+
+@example
+```
+import indentString = require('indent-string');
+
+indentString('Unicorns\nRainbows', 4);
+//=> '    Unicorns\n    Rainbows'
+
+indentString('Unicorns\nRainbows', 4, {indent: '♥'});
+//=> '♥♥♥♥Unicorns\n♥♥♥♥Rainbows'
+```
+*/
+declare function indentString(
+	string: string,
+	count?: number,
+	options?: indentString.Options
+): string;
+
+export = indentString;
diff --git a/server/node_modules/indent-string/index.js b/server/node_modules/indent-string/index.js
new file mode 100644
index 0000000..e1ab804
--- /dev/null
+++ b/server/node_modules/indent-string/index.js
@@ -0,0 +1,35 @@
+'use strict';
+
+module.exports = (string, count = 1, options) => {
+	options = {
+		indent: ' ',
+		includeEmptyLines: false,
+		...options
+	};
+
+	if (typeof string !== 'string') {
+		throw new TypeError(
+			`Expected \`input\` to be a \`string\`, got \`${typeof string}\``
+		);
+	}
+
+	if (typeof count !== 'number') {
+		throw new TypeError(
+			`Expected \`count\` to be a \`number\`, got \`${typeof count}\``
+		);
+	}
+
+	if (typeof options.indent !== 'string') {
+		throw new TypeError(
+			`Expected \`options.indent\` to be a \`string\`, got \`${typeof options.indent}\``
+		);
+	}
+
+	if (count === 0) {
+		return string;
+	}
+
+	const regex = options.includeEmptyLines ? /^/gm : /^(?!\s*$)/gm;
+
+	return string.replace(regex, options.indent.repeat(count));
+};
diff --git a/server/node_modules/indent-string/license b/server/node_modules/indent-string/license
new file mode 100644
index 0000000..e7af2f7
--- /dev/null
+++ b/server/node_modules/indent-string/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/indent-string/package.json b/server/node_modules/indent-string/package.json
new file mode 100644
index 0000000..497bb83
--- /dev/null
+++ b/server/node_modules/indent-string/package.json
@@ -0,0 +1,37 @@
+{
+	"name": "indent-string",
+	"version": "4.0.0",
+	"description": "Indent each line in a string",
+	"license": "MIT",
+	"repository": "sindresorhus/indent-string",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=8"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"indent",
+		"string",
+		"pad",
+		"align",
+		"line",
+		"text",
+		"each",
+		"every"
+	],
+	"devDependencies": {
+		"ava": "^1.4.1",
+		"tsd": "^0.7.2",
+		"xo": "^0.24.0"
+	}
+}
diff --git a/server/node_modules/indent-string/readme.md b/server/node_modules/indent-string/readme.md
new file mode 100644
index 0000000..49967de
--- /dev/null
+++ b/server/node_modules/indent-string/readme.md
@@ -0,0 +1,70 @@
+# indent-string [![Build Status](https://travis-ci.org/sindresorhus/indent-string.svg?branch=master)](https://travis-ci.org/sindresorhus/indent-string)
+
+> Indent each line in a string
+
+
+## Install
+
+```
+$ npm install indent-string
+```
+
+
+## Usage
+
+```js
+const indentString = require('indent-string');
+
+indentString('Unicorns\nRainbows', 4);
+//=> '    Unicorns\n    Rainbows'
+
+indentString('Unicorns\nRainbows', 4, {indent: '♥'});
+//=> '♥♥♥♥Unicorns\n♥♥♥♥Rainbows'
+```
+
+
+## API
+
+### indentString(string, [count], [options])
+
+#### string
+
+Type: `string`
+
+The string to indent.
+
+#### count
+
+Type: `number`<br>
+Default: `1`
+
+How many times you want `options.indent` repeated.
+
+#### options
+
+Type: `object`
+
+##### indent
+
+Type: `string`<br>
+Default: `' '`
+
+The string to use for the indent.
+
+##### includeEmptyLines
+
+Type: `boolean`<br>
+Default: `false`
+
+Also indent empty lines.
+
+
+## Related
+
+- [indent-string-cli](https://github.com/sindresorhus/indent-string-cli) - CLI for this module
+- [strip-indent](https://github.com/sindresorhus/strip-indent) - Strip leading whitespace from every line in a string
+
+
+## License
+
+MIT © [Sindre Sorhus](https://sindresorhus.com)
diff --git a/server/node_modules/infer-owner/LICENSE b/server/node_modules/infer-owner/LICENSE
new file mode 100644
index 0000000..20a4762
--- /dev/null
+++ b/server/node_modules/infer-owner/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) npm, Inc. and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/infer-owner/README.md b/server/node_modules/infer-owner/README.md
new file mode 100644
index 0000000..146caf7
--- /dev/null
+++ b/server/node_modules/infer-owner/README.md
@@ -0,0 +1,41 @@
+# infer-owner
+
+Infer the owner of a path based on the owner of its nearest existing parent
+
+## USAGE
+
+```js
+const inferOwner = require('infer-owner')
+
+inferOwner('/some/cache/folder/file').then(owner => {
+  // owner is {uid, gid} that should be attached to
+  // the /some/cache/folder/file, based on ownership
+  // of /some/cache/folder, /some/cache, /some, or /,
+  // whichever is the first to exist
+})
+
+// same, but not async
+const owner = inferOwner.sync('/some/cache/folder/file')
+
+// results are cached!  to reset the cache (eg, to change
+// permissions for whatever reason), do this:
+inferOwner.clearCache()
+```
+
+This module endeavors to be as performant as possible.  Parallel requests
+for ownership of the same path will only stat the directories one time.
+
+## API
+
+* `inferOwner(path) -> Promise<{ uid, gid }>`
+
+    If the path exists, return its uid and gid.  If it does not, look to
+    its parent, then its grandparent, and so on.
+
+* `inferOwner(path) -> { uid, gid }`
+
+    Sync form of `inferOwner(path)`.
+
+* `inferOwner.clearCache()`
+
+    Delete all cached ownership information and in-flight tracking.
diff --git a/server/node_modules/infer-owner/index.js b/server/node_modules/infer-owner/index.js
new file mode 100644
index 0000000..a7bddcb
--- /dev/null
+++ b/server/node_modules/infer-owner/index.js
@@ -0,0 +1,71 @@
+const cache = new Map()
+const fs = require('fs')
+const { dirname, resolve } = require('path')
+
+
+const lstat = path => new Promise((res, rej) =>
+  fs.lstat(path, (er, st) => er ? rej(er) : res(st)))
+
+const inferOwner = path => {
+  path = resolve(path)
+  if (cache.has(path))
+    return Promise.resolve(cache.get(path))
+
+  const statThen = st => {
+    const { uid, gid } = st
+    cache.set(path, { uid, gid })
+    return { uid, gid }
+  }
+  const parent = dirname(path)
+  const parentTrap = parent === path ? null : er => {
+    return inferOwner(parent).then((owner) => {
+      cache.set(path, owner)
+      return owner
+    })
+  }
+  return lstat(path).then(statThen, parentTrap)
+}
+
+const inferOwnerSync = path => {
+  path = resolve(path)
+  if (cache.has(path))
+    return cache.get(path)
+
+  const parent = dirname(path)
+
+  // avoid obscuring call site by re-throwing
+  // "catch" the error by returning from a finally,
+  // only if we're not at the root, and the parent call works.
+  let threw = true
+  try {
+    const st = fs.lstatSync(path)
+    threw = false
+    const { uid, gid } = st
+    cache.set(path, { uid, gid })
+    return { uid, gid }
+  } finally {
+    if (threw && parent !== path) {
+      const owner = inferOwnerSync(parent)
+      cache.set(path, owner)
+      return owner // eslint-disable-line no-unsafe-finally
+    }
+  }
+}
+
+const inflight = new Map()
+module.exports = path => {
+  path = resolve(path)
+  if (inflight.has(path))
+    return Promise.resolve(inflight.get(path))
+  const p = inferOwner(path).then(owner => {
+    inflight.delete(path)
+    return owner
+  })
+  inflight.set(path, p)
+  return p
+}
+module.exports.sync = inferOwnerSync
+module.exports.clearCache = () => {
+  cache.clear()
+  inflight.clear()
+}
diff --git a/server/node_modules/infer-owner/package.json b/server/node_modules/infer-owner/package.json
new file mode 100644
index 0000000..c4b2b6e
--- /dev/null
+++ b/server/node_modules/infer-owner/package.json
@@ -0,0 +1,26 @@
+{
+  "name": "infer-owner",
+  "version": "1.0.4",
+  "description": "Infer the owner of a path based on the owner of its nearest existing parent",
+  "author": "Isaac Z. Schlueter <i@izs.me> (https://izs.me)",
+  "license": "ISC",
+  "scripts": {
+    "test": "tap -J test/*.js --100",
+    "snap": "TAP_SNAPSHOT=1 tap -J test/*.js --100",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "devDependencies": {
+    "mutate-fs": "^2.1.1",
+    "tap": "^12.4.2"
+  },
+  "main": "index.js",
+  "repository": "https://github.com/npm/infer-owner",
+  "publishConfig": {
+    "access": "public"
+  },
+  "files": [
+    "index.js"
+  ]
+}
diff --git a/server/node_modules/inflight/LICENSE b/server/node_modules/inflight/LICENSE
new file mode 100644
index 0000000..05eeeb8
--- /dev/null
+++ b/server/node_modules/inflight/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/inflight/README.md b/server/node_modules/inflight/README.md
new file mode 100644
index 0000000..6dc8929
--- /dev/null
+++ b/server/node_modules/inflight/README.md
@@ -0,0 +1,37 @@
+# inflight
+
+Add callbacks to requests in flight to avoid async duplication
+
+## USAGE
+
+```javascript
+var inflight = require('inflight')
+
+// some request that does some stuff
+function req(key, callback) {
+  // key is any random string.  like a url or filename or whatever.
+  //
+  // will return either a falsey value, indicating that the
+  // request for this key is already in flight, or a new callback
+  // which when called will call all callbacks passed to inflightk
+  // with the same key
+  callback = inflight(key, callback)
+
+  // If we got a falsey value back, then there's already a req going
+  if (!callback) return
+
+  // this is where you'd fetch the url or whatever
+  // callback is also once()-ified, so it can safely be assigned
+  // to multiple events etc.  First call wins.
+  setTimeout(function() {
+    callback(null, key)
+  }, 100)
+}
+
+// only assigns a single setTimeout
+// when it dings, all cbs get called
+req('foo', cb1)
+req('foo', cb2)
+req('foo', cb3)
+req('foo', cb4)
+```
diff --git a/server/node_modules/inflight/inflight.js b/server/node_modules/inflight/inflight.js
new file mode 100644
index 0000000..48202b3
--- /dev/null
+++ b/server/node_modules/inflight/inflight.js
@@ -0,0 +1,54 @@
+var wrappy = require('wrappy')
+var reqs = Object.create(null)
+var once = require('once')
+
+module.exports = wrappy(inflight)
+
+function inflight (key, cb) {
+  if (reqs[key]) {
+    reqs[key].push(cb)
+    return null
+  } else {
+    reqs[key] = [cb]
+    return makeres(key)
+  }
+}
+
+function makeres (key) {
+  return once(function RES () {
+    var cbs = reqs[key]
+    var len = cbs.length
+    var args = slice(arguments)
+
+    // XXX It's somewhat ambiguous whether a new callback added in this
+    // pass should be queued for later execution if something in the
+    // list of callbacks throws, or if it should just be discarded.
+    // However, it's such an edge case that it hardly matters, and either
+    // choice is likely as surprising as the other.
+    // As it happens, we do go ahead and schedule it for later execution.
+    try {
+      for (var i = 0; i < len; i++) {
+        cbs[i].apply(null, args)
+      }
+    } finally {
+      if (cbs.length > len) {
+        // added more in the interim.
+        // de-zalgo, just in case, but don't call again.
+        cbs.splice(0, len)
+        process.nextTick(function () {
+          RES.apply(null, args)
+        })
+      } else {
+        delete reqs[key]
+      }
+    }
+  })
+}
+
+function slice (args) {
+  var length = args.length
+  var array = []
+
+  for (var i = 0; i < length; i++) array[i] = args[i]
+  return array
+}
diff --git a/server/node_modules/inflight/package.json b/server/node_modules/inflight/package.json
new file mode 100644
index 0000000..6084d35
--- /dev/null
+++ b/server/node_modules/inflight/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "inflight",
+  "version": "1.0.6",
+  "description": "Add callbacks to requests in flight to avoid async duplication",
+  "main": "inflight.js",
+  "files": [
+    "inflight.js"
+  ],
+  "dependencies": {
+    "once": "^1.3.0",
+    "wrappy": "1"
+  },
+  "devDependencies": {
+    "tap": "^7.1.2"
+  },
+  "scripts": {
+    "test": "tap test.js --100"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/npm/inflight.git"
+  },
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "bugs": {
+    "url": "https://github.com/isaacs/inflight/issues"
+  },
+  "homepage": "https://github.com/isaacs/inflight",
+  "license": "ISC"
+}
diff --git a/server/node_modules/inherits/LICENSE b/server/node_modules/inherits/LICENSE
new file mode 100644
index 0000000..dea3013
--- /dev/null
+++ b/server/node_modules/inherits/LICENSE
@@ -0,0 +1,16 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.
+
diff --git a/server/node_modules/inherits/README.md b/server/node_modules/inherits/README.md
new file mode 100644
index 0000000..b1c5665
--- /dev/null
+++ b/server/node_modules/inherits/README.md
@@ -0,0 +1,42 @@
+Browser-friendly inheritance fully compatible with standard node.js
+[inherits](http://nodejs.org/api/util.html#util_util_inherits_constructor_superconstructor).
+
+This package exports standard `inherits` from node.js `util` module in
+node environment, but also provides alternative browser-friendly
+implementation through [browser
+field](https://gist.github.com/shtylman/4339901). Alternative
+implementation is a literal copy of standard one located in standalone
+module to avoid requiring of `util`. It also has a shim for old
+browsers with no `Object.create` support.
+
+While keeping you sure you are using standard `inherits`
+implementation in node.js environment, it allows bundlers such as
+[browserify](https://github.com/substack/node-browserify) to not
+include full `util` package to your client code if all you need is
+just `inherits` function. It worth, because browser shim for `util`
+package is large and `inherits` is often the single function you need
+from it.
+
+It's recommended to use this package instead of
+`require('util').inherits` for any code that has chances to be used
+not only in node.js but in browser too.
+
+## usage
+
+```js
+var inherits = require('inherits');
+// then use exactly as the standard one
+```
+
+## note on version ~1.0
+
+Version ~1.0 had completely different motivation and is not compatible
+neither with 2.0 nor with standard node.js `inherits`.
+
+If you are using version ~1.0 and planning to switch to ~2.0, be
+careful:
+
+* new version uses `super_` instead of `super` for referencing
+  superclass
+* new version overwrites current prototype while old one preserves any
+  existing fields on it
diff --git a/server/node_modules/inherits/inherits.js b/server/node_modules/inherits/inherits.js
new file mode 100644
index 0000000..f71f2d9
--- /dev/null
+++ b/server/node_modules/inherits/inherits.js
@@ -0,0 +1,9 @@
+try {
+  var util = require('util');
+  /* istanbul ignore next */
+  if (typeof util.inherits !== 'function') throw '';
+  module.exports = util.inherits;
+} catch (e) {
+  /* istanbul ignore next */
+  module.exports = require('./inherits_browser.js');
+}
diff --git a/server/node_modules/inherits/inherits_browser.js b/server/node_modules/inherits/inherits_browser.js
new file mode 100644
index 0000000..86bbb3d
--- /dev/null
+++ b/server/node_modules/inherits/inherits_browser.js
@@ -0,0 +1,27 @@
+if (typeof Object.create === 'function') {
+  // implementation from standard node.js 'util' module
+  module.exports = function inherits(ctor, superCtor) {
+    if (superCtor) {
+      ctor.super_ = superCtor
+      ctor.prototype = Object.create(superCtor.prototype, {
+        constructor: {
+          value: ctor,
+          enumerable: false,
+          writable: true,
+          configurable: true
+        }
+      })
+    }
+  };
+} else {
+  // old school shim for old browsers
+  module.exports = function inherits(ctor, superCtor) {
+    if (superCtor) {
+      ctor.super_ = superCtor
+      var TempCtor = function () {}
+      TempCtor.prototype = superCtor.prototype
+      ctor.prototype = new TempCtor()
+      ctor.prototype.constructor = ctor
+    }
+  }
+}
diff --git a/server/node_modules/inherits/package.json b/server/node_modules/inherits/package.json
new file mode 100644
index 0000000..37b4366
--- /dev/null
+++ b/server/node_modules/inherits/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "inherits",
+  "description": "Browser-friendly inheritance fully compatible with standard node.js inherits()",
+  "version": "2.0.4",
+  "keywords": [
+    "inheritance",
+    "class",
+    "klass",
+    "oop",
+    "object-oriented",
+    "inherits",
+    "browser",
+    "browserify"
+  ],
+  "main": "./inherits.js",
+  "browser": "./inherits_browser.js",
+  "repository": "git://github.com/isaacs/inherits",
+  "license": "ISC",
+  "scripts": {
+    "test": "tap"
+  },
+  "devDependencies": {
+    "tap": "^14.2.4"
+  },
+  "files": [
+    "inherits.js",
+    "inherits_browser.js"
+  ]
+}
diff --git a/server/node_modules/ini/LICENSE b/server/node_modules/ini/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/ini/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/ini/README.md b/server/node_modules/ini/README.md
new file mode 100644
index 0000000..33df258
--- /dev/null
+++ b/server/node_modules/ini/README.md
@@ -0,0 +1,102 @@
+An ini format parser and serializer for node.
+
+Sections are treated as nested objects.  Items before the first
+heading are saved on the object directly.
+
+## Usage
+
+Consider an ini-file `config.ini` that looks like this:
+
+    ; this comment is being ignored
+    scope = global
+
+    [database]
+    user = dbuser
+    password = dbpassword
+    database = use_this_database
+
+    [paths.default]
+    datadir = /var/lib/data
+    array[] = first value
+    array[] = second value
+    array[] = third value
+
+You can read, manipulate and write the ini-file like so:
+
+    var fs = require('fs')
+      , ini = require('ini')
+
+    var config = ini.parse(fs.readFileSync('./config.ini', 'utf-8'))
+
+    config.scope = 'local'
+    config.database.database = 'use_another_database'
+    config.paths.default.tmpdir = '/tmp'
+    delete config.paths.default.datadir
+    config.paths.default.array.push('fourth value')
+
+    fs.writeFileSync('./config_modified.ini', ini.stringify(config, { section: 'section' }))
+
+This will result in a file called `config_modified.ini` being written
+to the filesystem with the following content:
+
+    [section]
+    scope=local
+    [section.database]
+    user=dbuser
+    password=dbpassword
+    database=use_another_database
+    [section.paths.default]
+    tmpdir=/tmp
+    array[]=first value
+    array[]=second value
+    array[]=third value
+    array[]=fourth value
+
+
+## API
+
+### decode(inistring)
+
+Decode the ini-style formatted `inistring` into a nested object.
+
+### parse(inistring)
+
+Alias for `decode(inistring)`
+
+### encode(object, [options])
+
+Encode the object `object` into an ini-style formatted string. If the
+optional parameter `section` is given, then all top-level properties
+of the object are put into this section and the `section`-string is
+prepended to all sub-sections, see the usage example above.
+
+The `options` object may contain the following:
+
+* `section` A string which will be the first `section` in the encoded
+  ini data.  Defaults to none.
+* `whitespace` Boolean to specify whether to put whitespace around the
+  `=` character.  By default, whitespace is omitted, to be friendly to
+  some persnickety old parsers that don't tolerate it well.  But some
+  find that it's more human-readable and pretty with the whitespace.
+
+For backwards compatibility reasons, if a `string` options is passed
+in, then it is assumed to be the `section` value.
+
+### stringify(object, [options])
+
+Alias for `encode(object, [options])`
+
+### safe(val)
+
+Escapes the string `val` such that it is safe to be used as a key or
+value in an ini-file. Basically escapes quotes. For example
+
+    ini.safe('"unsafe string"')
+
+would result in
+
+    "\"unsafe string\""
+
+### unsafe(val)
+
+Unescapes the string `val`
diff --git a/server/node_modules/ini/ini.js b/server/node_modules/ini/ini.js
new file mode 100644
index 0000000..b576f08
--- /dev/null
+++ b/server/node_modules/ini/ini.js
@@ -0,0 +1,206 @@
+exports.parse = exports.decode = decode
+
+exports.stringify = exports.encode = encode
+
+exports.safe = safe
+exports.unsafe = unsafe
+
+var eol = typeof process !== 'undefined' &&
+  process.platform === 'win32' ? '\r\n' : '\n'
+
+function encode (obj, opt) {
+  var children = []
+  var out = ''
+
+  if (typeof opt === 'string') {
+    opt = {
+      section: opt,
+      whitespace: false,
+    }
+  } else {
+    opt = opt || {}
+    opt.whitespace = opt.whitespace === true
+  }
+
+  var separator = opt.whitespace ? ' = ' : '='
+
+  Object.keys(obj).forEach(function (k, _, __) {
+    var val = obj[k]
+    if (val && Array.isArray(val)) {
+      val.forEach(function (item) {
+        out += safe(k + '[]') + separator + safe(item) + '\n'
+      })
+    } else if (val && typeof val === 'object')
+      children.push(k)
+    else
+      out += safe(k) + separator + safe(val) + eol
+  })
+
+  if (opt.section && out.length)
+    out = '[' + safe(opt.section) + ']' + eol + out
+
+  children.forEach(function (k, _, __) {
+    var nk = dotSplit(k).join('\\.')
+    var section = (opt.section ? opt.section + '.' : '') + nk
+    var child = encode(obj[k], {
+      section: section,
+      whitespace: opt.whitespace,
+    })
+    if (out.length && child.length)
+      out += eol
+
+    out += child
+  })
+
+  return out
+}
+
+function dotSplit (str) {
+  return str.replace(/\1/g, '\u0002LITERAL\\1LITERAL\u0002')
+    .replace(/\\\./g, '\u0001')
+    .split(/\./).map(function (part) {
+      return part.replace(/\1/g, '\\.')
+        .replace(/\2LITERAL\\1LITERAL\2/g, '\u0001')
+    })
+}
+
+function decode (str) {
+  var out = {}
+  var p = out
+  var section = null
+  //          section     |key      = value
+  var re = /^\[([^\]]*)\]$|^([^=]+)(=(.*))?$/i
+  var lines = str.split(/[\r\n]+/g)
+
+  lines.forEach(function (line, _, __) {
+    if (!line || line.match(/^\s*[;#]/))
+      return
+    var match = line.match(re)
+    if (!match)
+      return
+    if (match[1] !== undefined) {
+      section = unsafe(match[1])
+      if (section === '__proto__') {
+        // not allowed
+        // keep parsing the section, but don't attach it.
+        p = {}
+        return
+      }
+      p = out[section] = out[section] || {}
+      return
+    }
+    var key = unsafe(match[2])
+    if (key === '__proto__')
+      return
+    var value = match[3] ? unsafe(match[4]) : true
+    switch (value) {
+      case 'true':
+      case 'false':
+      case 'null': value = JSON.parse(value)
+    }
+
+    // Convert keys with '[]' suffix to an array
+    if (key.length > 2 && key.slice(-2) === '[]') {
+      key = key.substring(0, key.length - 2)
+      if (key === '__proto__')
+        return
+      if (!p[key])
+        p[key] = []
+      else if (!Array.isArray(p[key]))
+        p[key] = [p[key]]
+    }
+
+    // safeguard against resetting a previously defined
+    // array by accidentally forgetting the brackets
+    if (Array.isArray(p[key]))
+      p[key].push(value)
+    else
+      p[key] = value
+  })
+
+  // {a:{y:1},"a.b":{x:2}} --> {a:{y:1,b:{x:2}}}
+  // use a filter to return the keys that have to be deleted.
+  Object.keys(out).filter(function (k, _, __) {
+    if (!out[k] ||
+      typeof out[k] !== 'object' ||
+      Array.isArray(out[k]))
+      return false
+
+    // see if the parent section is also an object.
+    // if so, add it to that, and mark this one for deletion
+    var parts = dotSplit(k)
+    var p = out
+    var l = parts.pop()
+    var nl = l.replace(/\\\./g, '.')
+    parts.forEach(function (part, _, __) {
+      if (part === '__proto__')
+        return
+      if (!p[part] || typeof p[part] !== 'object')
+        p[part] = {}
+      p = p[part]
+    })
+    if (p === out && nl === l)
+      return false
+
+    p[nl] = out[k]
+    return true
+  }).forEach(function (del, _, __) {
+    delete out[del]
+  })
+
+  return out
+}
+
+function isQuoted (val) {
+  return (val.charAt(0) === '"' && val.slice(-1) === '"') ||
+    (val.charAt(0) === "'" && val.slice(-1) === "'")
+}
+
+function safe (val) {
+  return (typeof val !== 'string' ||
+    val.match(/[=\r\n]/) ||
+    val.match(/^\[/) ||
+    (val.length > 1 &&
+     isQuoted(val)) ||
+    val !== val.trim())
+    ? JSON.stringify(val)
+    : val.replace(/;/g, '\\;').replace(/#/g, '\\#')
+}
+
+function unsafe (val, doUnesc) {
+  val = (val || '').trim()
+  if (isQuoted(val)) {
+    // remove the single quotes before calling JSON.parse
+    if (val.charAt(0) === "'")
+      val = val.substr(1, val.length - 2)
+
+    try {
+      val = JSON.parse(val)
+    } catch (_) {}
+  } else {
+    // walk the val to find the first not-escaped ; character
+    var esc = false
+    var unesc = ''
+    for (var i = 0, l = val.length; i < l; i++) {
+      var c = val.charAt(i)
+      if (esc) {
+        if ('\\;#'.indexOf(c) !== -1)
+          unesc += c
+        else
+          unesc += '\\' + c
+
+        esc = false
+      } else if (';#'.indexOf(c) !== -1)
+        break
+      else if (c === '\\')
+        esc = true
+      else
+        unesc += c
+    }
+    if (esc)
+      unesc += '\\'
+
+    return unesc.trim()
+  }
+  return val
+}
diff --git a/server/node_modules/ini/package.json b/server/node_modules/ini/package.json
new file mode 100644
index 0000000..c830a35
--- /dev/null
+++ b/server/node_modules/ini/package.json
@@ -0,0 +1,33 @@
+{
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "name": "ini",
+  "description": "An ini encoder/decoder for node",
+  "version": "1.3.8",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/isaacs/ini.git"
+  },
+  "main": "ini.js",
+  "scripts": {
+    "eslint": "eslint",
+    "lint": "npm run eslint -- ini.js test/*.js",
+    "lintfix": "npm run lint -- --fix",
+    "test": "tap",
+    "posttest": "npm run lint",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags"
+  },
+  "devDependencies": {
+    "eslint": "^7.9.0",
+    "eslint-plugin-import": "^2.22.0",
+    "eslint-plugin-node": "^11.1.0",
+    "eslint-plugin-promise": "^4.2.1",
+    "eslint-plugin-standard": "^4.0.1",
+    "tap": "14"
+  },
+  "license": "ISC",
+  "files": [
+    "ini.js"
+  ]
+}
diff --git a/server/node_modules/ip-address/LICENSE b/server/node_modules/ip-address/LICENSE
new file mode 100644
index 0000000..ec79adb
--- /dev/null
+++ b/server/node_modules/ip-address/LICENSE
@@ -0,0 +1,19 @@
+Copyright (C) 2011 by Beau Gunderson
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/ip-address/README.md b/server/node_modules/ip-address/README.md
new file mode 100644
index 0000000..93ccb41
--- /dev/null
+++ b/server/node_modules/ip-address/README.md
@@ -0,0 +1,105 @@
+[![CircleCI](https://dl.circleci.com/status-badge/img/circleci/9fJmTZfn8d8p7GtVt688PY/JjriGjhcxBD6zYKygMZaet/tree/master.svg?style=svg&circle-token=7baede7efd3db5f1f25fb439e97d5f695ff76318)](https://dl.circleci.com/status-badge/redirect/circleci/9fJmTZfn8d8p7GtVt688PY/JjriGjhcxBD6zYKygMZaet/tree/master)
+[![codecov]](https://codecov.io/github/beaugunderson/ip-address?branch=master)
+[![downloads]](https://www.npmjs.com/package/ip-address)
+[![npm]](https://www.npmjs.com/package/ip-address)
+[![snyk]](https://snyk.io/test/github/beaugunderson/ip-address)
+
+[codecov]: https://codecov.io/github/beaugunderson/ip-address/coverage.svg?branch=master
+[downloads]: https://img.shields.io/npm/dm/ip-address.svg
+[npm]: https://img.shields.io/npm/v/ip-address.svg
+[snyk]: https://snyk.io/test/github/beaugunderson/ip-address/badge.svg
+
+## ip-address
+
+`ip-address` is a library for validating and manipulating IPv4 and IPv6
+addresses in JavaScript.
+
+### Upgrading from 9.x to 10.x
+
+The dependency on `jsbn` was removed thanks to
+[michal-kocarek](https://github.com/michal-kocarek). Thanks Michal! For
+clarity, all methods with BigInteger in the name were renamed to BigInt.
+
+#### Breaking changes
+
+- `#fromBigInteger()` → `#fromBigInt()`; now returns a native BigInt
+- `#bigInteger()` → `#bigInt()`; now returns a native BigInt
+
+### Documentation
+
+Documentation is available at [ip-address.js.org](http://ip-address.js.org/).
+
+### Examples
+
+```js
+var Address6 = require('ip-address').Address6;
+
+var address = new Address6('2001:0:ce49:7601:e866:efff:62c3:fffe');
+
+var teredo = address.inspectTeredo();
+
+teredo.client4;    // '157.60.0.1'
+```
+
+### Features
+
+- Usable via CommonJS or ESM
+- Parsing of all IPv6 notations
+- Parsing of IPv6 addresses and ports from URLs with `Address6.fromURL(url)`
+- Validity checking
+- Decoding of the [Teredo
+  information](http://en.wikipedia.org/wiki/Teredo_tunneling#IPv6_addressing)
+  in an address
+- Whether one address is a valid subnet of another
+- What special properties a given address has (multicast prefix, unique
+  local address prefix, etc.)
+- Number of subnets of a certain size in a given address
+- Display methods
+  - Hex, binary, and decimal
+  - Canonical form
+  - Correct form
+  - IPv4-compatible (i.e. `::ffff:192.168.0.1`)
+- Works in [node](http://nodejs.org/) and the browser (with browserify)
+- ~1,600 test cases
+
+### Used by
+
+- [anon](https://github.com/edsu/anon) which powers
+  [@congressedits](https://twitter.com/congressedits), among
+  [many others](https://github.com/edsu/anon#community)
+- [base85](https://github.com/noseglid/base85): base85 encoding/decoding
+- [contrail-web-core](https://github.com/Juniper/contrail-web-core): part of
+  Contrail, a network virtualization solution made by Juniper Networks
+- [dhcpjs](https://github.com/apaprocki/node-dhcpjs): a DHCP client and server
+- [epochtalk](https://github.com/epochtalk/epochtalk): next generation forum
+  software
+- [geoip-web](https://github.com/tfrce/node-geoip-web): a server for
+  quickly geolocating IP addresses
+- [hexabus](https://github.com/mysmartgrid/hexabus): an IPv6-based home
+  automation bus
+- [hubot-deploy](https://github.com/atmos/hubot-deploy): GitHub Flow via hubot
+- [heroku-portscanner](https://github.com/robison/heroku-portscanner): nmap
+  hosted on Heroku
+- [ipfs-swarm](https://github.com/diasdavid/node-ipfs-swarm): a swarm
+  implementation based on IPFS
+- [javascript-x-server](https://github.com/GothAck/javascript-x-server): an X
+  server written in JavaScript
+- [libnmap](https://github.com/jas-/node-libnmap): a node API for nmap
+- [mail-io](https://github.com/mofux/mail-io): a lightweight SMTP server
+- [maxmind-db-reader](https://github.com/PaddeK/node-maxmind-db): a library for
+  reading MaxMind database files
+- [proxy-protocol-v2](https://github.com/ably/proxy-protocol-v2): a proxy
+  protocol encoder/decoder built by [Ably](https://www.ably.io/)
+- [Samsara](https://github.com/mariusGundersen/Samsara): a Docker web interface
+- [sis-api](https://github.com/sis-cmdb/sis-api): a configuration management
+  database API
+- [socks5-client](https://github.com/mattcg/socks5-client): a SOCKS v5 client
+- [socksified](https://github.com/vially/node-socksified): a SOCKS v5 client
+- [socksv5](https://github.com/mscdex/socksv5): a SOCKS v5 server/client
+- [ssdapi](https://github.com/rsolomou/ssdapi): an API created by the
+  University of Portsmouth
+- [SwitchyOmega](https://github.com/FelisCatus/SwitchyOmega): a [Chrome
+  extension](https://chrome.google.com/webstore/detail/padekgcemlokbadohgkifijomclgjgif)
+  for switching between multiple proxies with ~311k users!
+- [swiz](https://github.com/racker/node-swiz): a serialization framework built
+  and used by [Rackspace](http://www.rackspace.com/)
diff --git a/server/node_modules/ip-address/dist/address-error.d.ts b/server/node_modules/ip-address/dist/address-error.d.ts
new file mode 100644
index 0000000..59b2165
--- /dev/null
+++ b/server/node_modules/ip-address/dist/address-error.d.ts
@@ -0,0 +1,5 @@
+export declare class AddressError extends Error {
+    parseMessage?: string;
+    constructor(message: string, parseMessage?: string);
+}
+//# sourceMappingURL=address-error.d.ts.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/address-error.d.ts.map b/server/node_modules/ip-address/dist/address-error.d.ts.map
new file mode 100644
index 0000000..0ef7fa6
--- /dev/null
+++ b/server/node_modules/ip-address/dist/address-error.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"address-error.d.ts","sourceRoot":"","sources":["../src/address-error.ts"],"names":[],"mappings":"AAAA,qBAAa,YAAa,SAAQ,KAAK;IACrC,YAAY,CAAC,EAAE,MAAM,CAAC;gBAEV,OAAO,EAAE,MAAM,EAAE,YAAY,CAAC,EAAE,MAAM;CAOnD"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/address-error.js b/server/node_modules/ip-address/dist/address-error.js
new file mode 100644
index 0000000..c178ae4
--- /dev/null
+++ b/server/node_modules/ip-address/dist/address-error.js
@@ -0,0 +1,12 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.AddressError = void 0;
+class AddressError extends Error {
+    constructor(message, parseMessage) {
+        super(message);
+        this.name = 'AddressError';
+        this.parseMessage = parseMessage;
+    }
+}
+exports.AddressError = AddressError;
+//# sourceMappingURL=address-error.js.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/address-error.js.map b/server/node_modules/ip-address/dist/address-error.js.map
new file mode 100644
index 0000000..5d71d13
--- /dev/null
+++ b/server/node_modules/ip-address/dist/address-error.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"address-error.js","sourceRoot":"","sources":["../src/address-error.ts"],"names":[],"mappings":";;;AAAA,MAAa,YAAa,SAAQ,KAAK;IAGrC,YAAY,OAAe,EAAE,YAAqB;QAChD,KAAK,CAAC,OAAO,CAAC,CAAC;QAEf,IAAI,CAAC,IAAI,GAAG,cAAc,CAAC;QAE3B,IAAI,CAAC,YAAY,GAAG,YAAY,CAAC;IACnC,CAAC;CACF;AAVD,oCAUC"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/common.d.ts b/server/node_modules/ip-address/dist/common.d.ts
new file mode 100644
index 0000000..a4250d8
--- /dev/null
+++ b/server/node_modules/ip-address/dist/common.d.ts
@@ -0,0 +1,15 @@
+import { Address4 } from './ipv4';
+import { Address6 } from './ipv6';
+export interface ReverseFormOptions {
+    omitSuffix?: boolean;
+}
+export declare function isInSubnet(this: Address4 | Address6, address: Address4 | Address6): boolean;
+export declare function isCorrect(defaultBits: number): (this: Address4 | Address6) => boolean;
+export declare function numberToPaddedHex(number: number): string;
+export declare function stringToPaddedHex(numberString: string): string;
+/**
+ * @param binaryValue Binary representation of a value (e.g. `10`)
+ * @param position Byte position, where 0 is the least significant bit
+ */
+export declare function testBit(binaryValue: string, position: number): boolean;
+//# sourceMappingURL=common.d.ts.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/common.d.ts.map b/server/node_modules/ip-address/dist/common.d.ts.map
new file mode 100644
index 0000000..d13705a
--- /dev/null
+++ b/server/node_modules/ip-address/dist/common.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"common.d.ts","sourceRoot":"","sources":["../src/common.ts"],"names":[],"mappings":"AAAA,OAAO,EAAE,QAAQ,EAAE,MAAM,QAAQ,CAAC;AAClC,OAAO,EAAE,QAAQ,EAAE,MAAM,QAAQ,CAAC;AAElC,MAAM,WAAW,kBAAkB;IACjC,UAAU,CAAC,EAAE,OAAO,CAAC;CACtB;AAED,wBAAgB,UAAU,CAAC,IAAI,EAAE,QAAQ,GAAG,QAAQ,EAAE,OAAO,EAAE,QAAQ,GAAG,QAAQ,WAUjF;AAED,wBAAgB,SAAS,CAAC,WAAW,EAAE,MAAM,UACpB,QAAQ,GAAG,QAAQ,aAW3C;AAED,wBAAgB,iBAAiB,CAAC,MAAM,EAAE,MAAM,UAE/C;AAED,wBAAgB,iBAAiB,CAAC,YAAY,EAAE,MAAM,UAErD;AAED;;;GAGG;AACH,wBAAgB,OAAO,CAAC,WAAW,EAAE,MAAM,EAAE,QAAQ,EAAE,MAAM,GAAG,OAAO,CAStE"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/common.js b/server/node_modules/ip-address/dist/common.js
new file mode 100644
index 0000000..273a01e
--- /dev/null
+++ b/server/node_modules/ip-address/dist/common.js
@@ -0,0 +1,46 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.isInSubnet = isInSubnet;
+exports.isCorrect = isCorrect;
+exports.numberToPaddedHex = numberToPaddedHex;
+exports.stringToPaddedHex = stringToPaddedHex;
+exports.testBit = testBit;
+function isInSubnet(address) {
+    if (this.subnetMask < address.subnetMask) {
+        return false;
+    }
+    if (this.mask(address.subnetMask) === address.mask()) {
+        return true;
+    }
+    return false;
+}
+function isCorrect(defaultBits) {
+    return function () {
+        if (this.addressMinusSuffix !== this.correctForm()) {
+            return false;
+        }
+        if (this.subnetMask === defaultBits && !this.parsedSubnet) {
+            return true;
+        }
+        return this.parsedSubnet === String(this.subnetMask);
+    };
+}
+function numberToPaddedHex(number) {
+    return number.toString(16).padStart(2, '0');
+}
+function stringToPaddedHex(numberString) {
+    return numberToPaddedHex(parseInt(numberString, 10));
+}
+/**
+ * @param binaryValue Binary representation of a value (e.g. `10`)
+ * @param position Byte position, where 0 is the least significant bit
+ */
+function testBit(binaryValue, position) {
+    const { length } = binaryValue;
+    if (position > length) {
+        return false;
+    }
+    const positionInString = length - position;
+    return binaryValue.substring(positionInString, positionInString + 1) === '1';
+}
+//# sourceMappingURL=common.js.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/common.js.map b/server/node_modules/ip-address/dist/common.js.map
new file mode 100644
index 0000000..036ce66
--- /dev/null
+++ b/server/node_modules/ip-address/dist/common.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"common.js","sourceRoot":"","sources":["../src/common.ts"],"names":[],"mappings":";;AAOA,gCAUC;AAED,8BAYC;AAED,8CAEC;AAED,8CAEC;AAMD,0BASC;AA/CD,SAAgB,UAAU,CAA4B,OAA4B;IAChF,IAAI,IAAI,CAAC,UAAU,GAAG,OAAO,CAAC,UAAU,EAAE,CAAC;QACzC,OAAO,KAAK,CAAC;IACf,CAAC;IAED,IAAI,IAAI,CAAC,IAAI,CAAC,OAAO,CAAC,UAAU,CAAC,KAAK,OAAO,CAAC,IAAI,EAAE,EAAE,CAAC;QACrD,OAAO,IAAI,CAAC;IACd,CAAC;IAED,OAAO,KAAK,CAAC;AACf,CAAC;AAED,SAAgB,SAAS,CAAC,WAAmB;IAC3C,OAAO;QACL,IAAI,IAAI,CAAC,kBAAkB,KAAK,IAAI,CAAC,WAAW,EAAE,EAAE,CAAC;YACnD,OAAO,KAAK,CAAC;QACf,CAAC;QAED,IAAI,IAAI,CAAC,UAAU,KAAK,WAAW,IAAI,CAAC,IAAI,CAAC,YAAY,EAAE,CAAC;YAC1D,OAAO,IAAI,CAAC;QACd,CAAC;QAED,OAAO,IAAI,CAAC,YAAY,KAAK,MAAM,CAAC,IAAI,CAAC,UAAU,CAAC,CAAC;IACvD,CAAC,CAAC;AACJ,CAAC;AAED,SAAgB,iBAAiB,CAAC,MAAc;IAC9C,OAAO,MAAM,CAAC,QAAQ,CAAC,EAAE,CAAC,CAAC,QAAQ,CAAC,CAAC,EAAE,GAAG,CAAC,CAAC;AAC9C,CAAC;AAED,SAAgB,iBAAiB,CAAC,YAAoB;IACpD,OAAO,iBAAiB,CAAC,QAAQ,CAAC,YAAY,EAAE,EAAE,CAAC,CAAC,CAAC;AACvD,CAAC;AAED;;;GAGG;AACH,SAAgB,OAAO,CAAC,WAAmB,EAAE,QAAgB;IAC3D,MAAM,EAAE,MAAM,EAAE,GAAG,WAAW,CAAC;IAE/B,IAAI,QAAQ,GAAG,MAAM,EAAE,CAAC;QACtB,OAAO,KAAK,CAAC;IACf,CAAC;IAED,MAAM,gBAAgB,GAAG,MAAM,GAAG,QAAQ,CAAC;IAC3C,OAAO,WAAW,CAAC,SAAS,CAAC,gBAAgB,EAAE,gBAAgB,GAAG,CAAC,CAAC,KAAK,GAAG,CAAC;AAC/E,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ip-address.d.ts b/server/node_modules/ip-address/dist/ip-address.d.ts
new file mode 100644
index 0000000..14f8fe0
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ip-address.d.ts
@@ -0,0 +1,8 @@
+export { Address4 } from './ipv4';
+export { Address6 } from './ipv6';
+export { AddressError } from './address-error';
+import * as helpers from './v6/helpers';
+export declare const v6: {
+    helpers: typeof helpers;
+};
+//# sourceMappingURL=ip-address.d.ts.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ip-address.d.ts.map b/server/node_modules/ip-address/dist/ip-address.d.ts.map
new file mode 100644
index 0000000..7bcb98a
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ip-address.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"ip-address.d.ts","sourceRoot":"","sources":["../src/ip-address.ts"],"names":[],"mappings":"AAAA,OAAO,EAAE,QAAQ,EAAE,MAAM,QAAQ,CAAC;AAClC,OAAO,EAAE,QAAQ,EAAE,MAAM,QAAQ,CAAC;AAClC,OAAO,EAAE,YAAY,EAAE,MAAM,iBAAiB,CAAC;AAE/C,OAAO,KAAK,OAAO,MAAM,cAAc,CAAC;AAExC,eAAO,MAAM,EAAE;;CAAc,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ip-address.js b/server/node_modules/ip-address/dist/ip-address.js
new file mode 100644
index 0000000..84f3487
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ip-address.js
@@ -0,0 +1,35 @@
+"use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.v6 = exports.AddressError = exports.Address6 = exports.Address4 = void 0;
+var ipv4_1 = require("./ipv4");
+Object.defineProperty(exports, "Address4", { enumerable: true, get: function () { return ipv4_1.Address4; } });
+var ipv6_1 = require("./ipv6");
+Object.defineProperty(exports, "Address6", { enumerable: true, get: function () { return ipv6_1.Address6; } });
+var address_error_1 = require("./address-error");
+Object.defineProperty(exports, "AddressError", { enumerable: true, get: function () { return address_error_1.AddressError; } });
+const helpers = __importStar(require("./v6/helpers"));
+exports.v6 = { helpers };
+//# sourceMappingURL=ip-address.js.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ip-address.js.map b/server/node_modules/ip-address/dist/ip-address.js.map
new file mode 100644
index 0000000..cb89ed3
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ip-address.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"ip-address.js","sourceRoot":"","sources":["../src/ip-address.ts"],"names":[],"mappings":";;;;;;;;;;;;;;;;;;;;;;;;;;AAAA,+BAAkC;AAAzB,gGAAA,QAAQ,OAAA;AACjB,+BAAkC;AAAzB,gGAAA,QAAQ,OAAA;AACjB,iDAA+C;AAAtC,6GAAA,YAAY,OAAA;AAErB,sDAAwC;AAE3B,QAAA,EAAE,GAAG,EAAE,OAAO,EAAE,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ipv4.d.ts b/server/node_modules/ip-address/dist/ipv4.d.ts
new file mode 100644
index 0000000..28edbaa
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ipv4.d.ts
@@ -0,0 +1,209 @@
+import * as common from './common';
+/**
+ * Represents an IPv4 address
+ * @class Address4
+ * @param {string} address - An IPv4 address string
+ */
+export declare class Address4 {
+    address: string;
+    addressMinusSuffix?: string;
+    groups: number;
+    parsedAddress: string[];
+    parsedSubnet: string;
+    subnet: string;
+    subnetMask: number;
+    v4: boolean;
+    constructor(address: string);
+    static isValid(address: string): boolean;
+    parse(address: string): string[];
+    /**
+     * Returns the correct form of an address
+     * @memberof Address4
+     * @instance
+     * @returns {String}
+     */
+    correctForm(): string;
+    /**
+     * Returns true if the address is correct, false otherwise
+     * @memberof Address4
+     * @instance
+     * @returns {Boolean}
+     */
+    isCorrect: (this: Address4 | import("./ipv6").Address6) => boolean;
+    /**
+     * Converts a hex string to an IPv4 address object
+     * @memberof Address4
+     * @static
+     * @param {string} hex - a hex string to convert
+     * @returns {Address4}
+     */
+    static fromHex(hex: string): Address4;
+    /**
+     * Converts an integer into a IPv4 address object
+     * @memberof Address4
+     * @static
+     * @param {integer} integer - a number to convert
+     * @returns {Address4}
+     */
+    static fromInteger(integer: number): Address4;
+    /**
+     * Return an address from in-addr.arpa form
+     * @memberof Address4
+     * @static
+     * @param {string} arpaFormAddress - an 'in-addr.arpa' form ipv4 address
+     * @returns {Adress4}
+     * @example
+     * var address = Address4.fromArpa(42.2.0.192.in-addr.arpa.)
+     * address.correctForm(); // '192.0.2.42'
+     */
+    static fromArpa(arpaFormAddress: string): Address4;
+    /**
+     * Converts an IPv4 address object to a hex string
+     * @memberof Address4
+     * @instance
+     * @returns {String}
+     */
+    toHex(): string;
+    /**
+     * Converts an IPv4 address object to an array of bytes
+     * @memberof Address4
+     * @instance
+     * @returns {Array}
+     */
+    toArray(): number[];
+    /**
+     * Converts an IPv4 address object to an IPv6 address group
+     * @memberof Address4
+     * @instance
+     * @returns {String}
+     */
+    toGroup6(): string;
+    /**
+     * Returns the address as a `bigint`
+     * @memberof Address4
+     * @instance
+     * @returns {bigint}
+     */
+    bigInt(): bigint;
+    /**
+     * Helper function getting start address.
+     * @memberof Address4
+     * @instance
+     * @returns {bigint}
+     */
+    _startAddress(): bigint;
+    /**
+     * The first address in the range given by this address' subnet.
+     * Often referred to as the Network Address.
+     * @memberof Address4
+     * @instance
+     * @returns {Address4}
+     */
+    startAddress(): Address4;
+    /**
+     * The first host address in the range given by this address's subnet ie
+     * the first address after the Network Address
+     * @memberof Address4
+     * @instance
+     * @returns {Address4}
+     */
+    startAddressExclusive(): Address4;
+    /**
+     * Helper function getting end address.
+     * @memberof Address4
+     * @instance
+     * @returns {bigint}
+     */
+    _endAddress(): bigint;
+    /**
+     * The last address in the range given by this address' subnet
+     * Often referred to as the Broadcast
+     * @memberof Address4
+     * @instance
+     * @returns {Address4}
+     */
+    endAddress(): Address4;
+    /**
+     * The last host address in the range given by this address's subnet ie
+     * the last address prior to the Broadcast Address
+     * @memberof Address4
+     * @instance
+     * @returns {Address4}
+     */
+    endAddressExclusive(): Address4;
+    /**
+     * Converts a BigInt to a v4 address object
+     * @memberof Address4
+     * @static
+     * @param {bigint} bigInt - a BigInt to convert
+     * @returns {Address4}
+     */
+    static fromBigInt(bigInt: bigint): Address4;
+    /**
+     * Convert a byte array to an Address4 object
+     * @memberof Address4
+     * @static
+     * @param {Array<number>} bytes - an array of 4 bytes (0-255)
+     * @returns {Address4}
+     */
+    static fromByteArray(bytes: Array<number>): Address4;
+    /**
+     * Convert an unsigned byte array to an Address4 object
+     * @memberof Address4
+     * @static
+     * @param {Array<number>} bytes - an array of 4 unsigned bytes (0-255)
+     * @returns {Address4}
+     */
+    static fromUnsignedByteArray(bytes: Array<number>): Address4;
+    /**
+     * Returns the first n bits of the address, defaulting to the
+     * subnet mask
+     * @memberof Address4
+     * @instance
+     * @returns {String}
+     */
+    mask(mask?: number): string;
+    /**
+     * Returns the bits in the given range as a base-2 string
+     * @memberof Address4
+     * @instance
+     * @returns {string}
+     */
+    getBitsBase2(start: number, end: number): string;
+    /**
+     * Return the reversed ip6.arpa form of the address
+     * @memberof Address4
+     * @param {Object} options
+     * @param {boolean} options.omitSuffix - omit the "in-addr.arpa" suffix
+     * @instance
+     * @returns {String}
+     */
+    reverseForm(options?: common.ReverseFormOptions): string;
+    /**
+     * Returns true if the given address is in the subnet of the current address
+     * @memberof Address4
+     * @instance
+     * @returns {boolean}
+     */
+    isInSubnet: typeof common.isInSubnet;
+    /**
+     * Returns true if the given address is a multicast address
+     * @memberof Address4
+     * @instance
+     * @returns {boolean}
+     */
+    isMulticast(): boolean;
+    /**
+     * Returns a zero-padded base-2 string representation of the address
+     * @memberof Address4
+     * @instance
+     * @returns {string}
+     */
+    binaryZeroPad(): string;
+    /**
+     * Groups an IPv4 address for inclusion at the end of an IPv6 address
+     * @returns {String}
+     */
+    groupForV6(): string;
+}
+//# sourceMappingURL=ipv4.d.ts.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ipv4.d.ts.map b/server/node_modules/ip-address/dist/ipv4.d.ts.map
new file mode 100644
index 0000000..165d459
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ipv4.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"ipv4.d.ts","sourceRoot":"","sources":["../src/ipv4.ts"],"names":[],"mappings":"AAEA,OAAO,KAAK,MAAM,MAAM,UAAU,CAAC;AAInC;;;;GAIG;AACH,qBAAa,QAAQ;IACnB,OAAO,EAAE,MAAM,CAAC;IAChB,kBAAkB,CAAC,EAAE,MAAM,CAAC;IAC5B,MAAM,EAAE,MAAM,CAAoB;IAClC,aAAa,EAAE,MAAM,EAAE,CAAM;IAC7B,YAAY,EAAE,MAAM,CAAM;IAC1B,MAAM,EAAE,MAAM,CAAS;IACvB,UAAU,EAAE,MAAM,CAAM;IACxB,EAAE,EAAE,OAAO,CAAQ;gBAEP,OAAO,EAAE,MAAM;IAsB3B,MAAM,CAAC,OAAO,CAAC,OAAO,EAAE,MAAM,GAAG,OAAO;IAcxC,KAAK,CAAC,OAAO,EAAE,MAAM;IAUrB;;;;;OAKG;IACH,WAAW,IAAI,MAAM;IAIrB;;;;;OAKG;IACH,SAAS,0DAAoC;IAE7C;;;;;;OAMG;IACH,MAAM,CAAC,OAAO,CAAC,GAAG,EAAE,MAAM,GAAG,QAAQ;IAcrC;;;;;;OAMG;IACH,MAAM,CAAC,WAAW,CAAC,OAAO,EAAE,MAAM,GAAG,QAAQ;IAI7C;;;;;;;;;OASG;IACH,MAAM,CAAC,QAAQ,CAAC,eAAe,EAAE,MAAM,GAAG,QAAQ;IASlD;;;;;OAKG;IACH,KAAK,IAAI,MAAM;IAIf;;;;;OAKG;IACH,OAAO,IAAI,MAAM,EAAE;IAInB;;;;;OAKG;IACH,QAAQ,IAAI,MAAM;IAelB;;;;;OAKG;IACH,MAAM,IAAI,MAAM;IAIhB;;;;;OAKG;IACH,aAAa,IAAI,MAAM;IAIvB;;;;;;OAMG;IACH,YAAY,IAAI,QAAQ;IAIxB;;;;;;OAMG;IACH,qBAAqB,IAAI,QAAQ;IAKjC;;;;;OAKG;IACH,WAAW,IAAI,MAAM;IAIrB;;;;;;OAMG;IACH,UAAU,IAAI,QAAQ;IAItB;;;;;;OAMG;IACH,mBAAmB,IAAI,QAAQ;IAK/B;;;;;;OAMG;IACH,MAAM,CAAC,UAAU,CAAC,MAAM,EAAE,MAAM,GAAG,QAAQ;IAI3C;;;;;;OAMG;IACH,MAAM,CAAC,aAAa,CAAC,KAAK,EAAE,KAAK,CAAC,MAAM,CAAC,GAAG,QAAQ;IAepD;;;;;;OAMG;IACH,MAAM,CAAC,qBAAqB,CAAC,KAAK,EAAE,KAAK,CAAC,MAAM,CAAC,GAAG,QAAQ;IAS5D;;;;;;OAMG;IACH,IAAI,CAAC,IAAI,CAAC,EAAE,MAAM,GAAG,MAAM;IAQ3B;;;;;OAKG;IACH,YAAY,CAAC,KAAK,EAAE,MAAM,EAAE,GAAG,EAAE,MAAM,GAAG,MAAM;IAIhD;;;;;;;OAOG;IACH,WAAW,CAAC,OAAO,CAAC,EAAE,MAAM,CAAC,kBAAkB,GAAG,MAAM;IAcxD;;;;;OAKG;IACH,UAAU,2BAAqB;IAE/B;;;;;OAKG;IACH,WAAW,IAAI,OAAO;IAItB;;;;;OAKG;IACH,aAAa,IAAI,MAAM;IAIvB;;;OAGG;IACH,UAAU,IAAI,MAAM;CAYrB"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ipv4.js b/server/node_modules/ip-address/dist/ipv4.js
new file mode 100644
index 0000000..311c89c
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ipv4.js
@@ -0,0 +1,360 @@
+"use strict";
+/* eslint-disable no-param-reassign */
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.Address4 = void 0;
+const common = __importStar(require("./common"));
+const constants = __importStar(require("./v4/constants"));
+const address_error_1 = require("./address-error");
+/**
+ * Represents an IPv4 address
+ * @class Address4
+ * @param {string} address - An IPv4 address string
+ */
+class Address4 {
+    constructor(address) {
+        this.groups = constants.GROUPS;
+        this.parsedAddress = [];
+        this.parsedSubnet = '';
+        this.subnet = '/32';
+        this.subnetMask = 32;
+        this.v4 = true;
+        /**
+         * Returns true if the address is correct, false otherwise
+         * @memberof Address4
+         * @instance
+         * @returns {Boolean}
+         */
+        this.isCorrect = common.isCorrect(constants.BITS);
+        /**
+         * Returns true if the given address is in the subnet of the current address
+         * @memberof Address4
+         * @instance
+         * @returns {boolean}
+         */
+        this.isInSubnet = common.isInSubnet;
+        this.address = address;
+        const subnet = constants.RE_SUBNET_STRING.exec(address);
+        if (subnet) {
+            this.parsedSubnet = subnet[0].replace('/', '');
+            this.subnetMask = parseInt(this.parsedSubnet, 10);
+            this.subnet = `/${this.subnetMask}`;
+            if (this.subnetMask < 0 || this.subnetMask > constants.BITS) {
+                throw new address_error_1.AddressError('Invalid subnet mask.');
+            }
+            address = address.replace(constants.RE_SUBNET_STRING, '');
+        }
+        this.addressMinusSuffix = address;
+        this.parsedAddress = this.parse(address);
+    }
+    static isValid(address) {
+        try {
+            // eslint-disable-next-line no-new
+            new Address4(address);
+            return true;
+        }
+        catch (e) {
+            return false;
+        }
+    }
+    /*
+     * Parses a v4 address
+     */
+    parse(address) {
+        const groups = address.split('.');
+        if (!address.match(constants.RE_ADDRESS)) {
+            throw new address_error_1.AddressError('Invalid IPv4 address.');
+        }
+        return groups;
+    }
+    /**
+     * Returns the correct form of an address
+     * @memberof Address4
+     * @instance
+     * @returns {String}
+     */
+    correctForm() {
+        return this.parsedAddress.map((part) => parseInt(part, 10)).join('.');
+    }
+    /**
+     * Converts a hex string to an IPv4 address object
+     * @memberof Address4
+     * @static
+     * @param {string} hex - a hex string to convert
+     * @returns {Address4}
+     */
+    static fromHex(hex) {
+        const padded = hex.replace(/:/g, '').padStart(8, '0');
+        const groups = [];
+        let i;
+        for (i = 0; i < 8; i += 2) {
+            const h = padded.slice(i, i + 2);
+            groups.push(parseInt(h, 16));
+        }
+        return new Address4(groups.join('.'));
+    }
+    /**
+     * Converts an integer into a IPv4 address object
+     * @memberof Address4
+     * @static
+     * @param {integer} integer - a number to convert
+     * @returns {Address4}
+     */
+    static fromInteger(integer) {
+        return Address4.fromHex(integer.toString(16));
+    }
+    /**
+     * Return an address from in-addr.arpa form
+     * @memberof Address4
+     * @static
+     * @param {string} arpaFormAddress - an 'in-addr.arpa' form ipv4 address
+     * @returns {Adress4}
+     * @example
+     * var address = Address4.fromArpa(42.2.0.192.in-addr.arpa.)
+     * address.correctForm(); // '192.0.2.42'
+     */
+    static fromArpa(arpaFormAddress) {
+        // remove ending ".in-addr.arpa." or just "."
+        const leader = arpaFormAddress.replace(/(\.in-addr\.arpa)?\.$/, '');
+        const address = leader.split('.').reverse().join('.');
+        return new Address4(address);
+    }
+    /**
+     * Converts an IPv4 address object to a hex string
+     * @memberof Address4
+     * @instance
+     * @returns {String}
+     */
+    toHex() {
+        return this.parsedAddress.map((part) => common.stringToPaddedHex(part)).join(':');
+    }
+    /**
+     * Converts an IPv4 address object to an array of bytes
+     * @memberof Address4
+     * @instance
+     * @returns {Array}
+     */
+    toArray() {
+        return this.parsedAddress.map((part) => parseInt(part, 10));
+    }
+    /**
+     * Converts an IPv4 address object to an IPv6 address group
+     * @memberof Address4
+     * @instance
+     * @returns {String}
+     */
+    toGroup6() {
+        const output = [];
+        let i;
+        for (i = 0; i < constants.GROUPS; i += 2) {
+            output.push(`${common.stringToPaddedHex(this.parsedAddress[i])}${common.stringToPaddedHex(this.parsedAddress[i + 1])}`);
+        }
+        return output.join(':');
+    }
+    /**
+     * Returns the address as a `bigint`
+     * @memberof Address4
+     * @instance
+     * @returns {bigint}
+     */
+    bigInt() {
+        return BigInt(`0x${this.parsedAddress.map((n) => common.stringToPaddedHex(n)).join('')}`);
+    }
+    /**
+     * Helper function getting start address.
+     * @memberof Address4
+     * @instance
+     * @returns {bigint}
+     */
+    _startAddress() {
+        return BigInt(`0b${this.mask() + '0'.repeat(constants.BITS - this.subnetMask)}`);
+    }
+    /**
+     * The first address in the range given by this address' subnet.
+     * Often referred to as the Network Address.
+     * @memberof Address4
+     * @instance
+     * @returns {Address4}
+     */
+    startAddress() {
+        return Address4.fromBigInt(this._startAddress());
+    }
+    /**
+     * The first host address in the range given by this address's subnet ie
+     * the first address after the Network Address
+     * @memberof Address4
+     * @instance
+     * @returns {Address4}
+     */
+    startAddressExclusive() {
+        const adjust = BigInt('1');
+        return Address4.fromBigInt(this._startAddress() + adjust);
+    }
+    /**
+     * Helper function getting end address.
+     * @memberof Address4
+     * @instance
+     * @returns {bigint}
+     */
+    _endAddress() {
+        return BigInt(`0b${this.mask() + '1'.repeat(constants.BITS - this.subnetMask)}`);
+    }
+    /**
+     * The last address in the range given by this address' subnet
+     * Often referred to as the Broadcast
+     * @memberof Address4
+     * @instance
+     * @returns {Address4}
+     */
+    endAddress() {
+        return Address4.fromBigInt(this._endAddress());
+    }
+    /**
+     * The last host address in the range given by this address's subnet ie
+     * the last address prior to the Broadcast Address
+     * @memberof Address4
+     * @instance
+     * @returns {Address4}
+     */
+    endAddressExclusive() {
+        const adjust = BigInt('1');
+        return Address4.fromBigInt(this._endAddress() - adjust);
+    }
+    /**
+     * Converts a BigInt to a v4 address object
+     * @memberof Address4
+     * @static
+     * @param {bigint} bigInt - a BigInt to convert
+     * @returns {Address4}
+     */
+    static fromBigInt(bigInt) {
+        return Address4.fromHex(bigInt.toString(16));
+    }
+    /**
+     * Convert a byte array to an Address4 object
+     * @memberof Address4
+     * @static
+     * @param {Array<number>} bytes - an array of 4 bytes (0-255)
+     * @returns {Address4}
+     */
+    static fromByteArray(bytes) {
+        if (bytes.length !== 4) {
+            throw new address_error_1.AddressError('IPv4 addresses require exactly 4 bytes');
+        }
+        // Validate that all bytes are within valid range (0-255)
+        for (let i = 0; i < bytes.length; i++) {
+            if (!Number.isInteger(bytes[i]) || bytes[i] < 0 || bytes[i] > 255) {
+                throw new address_error_1.AddressError('All bytes must be integers between 0 and 255');
+            }
+        }
+        return this.fromUnsignedByteArray(bytes);
+    }
+    /**
+     * Convert an unsigned byte array to an Address4 object
+     * @memberof Address4
+     * @static
+     * @param {Array<number>} bytes - an array of 4 unsigned bytes (0-255)
+     * @returns {Address4}
+     */
+    static fromUnsignedByteArray(bytes) {
+        if (bytes.length !== 4) {
+            throw new address_error_1.AddressError('IPv4 addresses require exactly 4 bytes');
+        }
+        const address = bytes.join('.');
+        return new Address4(address);
+    }
+    /**
+     * Returns the first n bits of the address, defaulting to the
+     * subnet mask
+     * @memberof Address4
+     * @instance
+     * @returns {String}
+     */
+    mask(mask) {
+        if (mask === undefined) {
+            mask = this.subnetMask;
+        }
+        return this.getBitsBase2(0, mask);
+    }
+    /**
+     * Returns the bits in the given range as a base-2 string
+     * @memberof Address4
+     * @instance
+     * @returns {string}
+     */
+    getBitsBase2(start, end) {
+        return this.binaryZeroPad().slice(start, end);
+    }
+    /**
+     * Return the reversed ip6.arpa form of the address
+     * @memberof Address4
+     * @param {Object} options
+     * @param {boolean} options.omitSuffix - omit the "in-addr.arpa" suffix
+     * @instance
+     * @returns {String}
+     */
+    reverseForm(options) {
+        if (!options) {
+            options = {};
+        }
+        const reversed = this.correctForm().split('.').reverse().join('.');
+        if (options.omitSuffix) {
+            return reversed;
+        }
+        return `${reversed}.in-addr.arpa.`;
+    }
+    /**
+     * Returns true if the given address is a multicast address
+     * @memberof Address4
+     * @instance
+     * @returns {boolean}
+     */
+    isMulticast() {
+        return this.isInSubnet(new Address4('224.0.0.0/4'));
+    }
+    /**
+     * Returns a zero-padded base-2 string representation of the address
+     * @memberof Address4
+     * @instance
+     * @returns {string}
+     */
+    binaryZeroPad() {
+        return this.bigInt().toString(2).padStart(constants.BITS, '0');
+    }
+    /**
+     * Groups an IPv4 address for inclusion at the end of an IPv6 address
+     * @returns {String}
+     */
+    groupForV6() {
+        const segments = this.parsedAddress;
+        return this.address.replace(constants.RE_ADDRESS, `<span class="hover-group group-v4 group-6">${segments
+            .slice(0, 2)
+            .join('.')}</span>.<span class="hover-group group-v4 group-7">${segments
+            .slice(2, 4)
+            .join('.')}</span>`);
+    }
+}
+exports.Address4 = Address4;
+//# sourceMappingURL=ipv4.js.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ipv4.js.map b/server/node_modules/ip-address/dist/ipv4.js.map
new file mode 100644
index 0000000..2b4e928
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ipv4.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"ipv4.js","sourceRoot":"","sources":["../src/ipv4.ts"],"names":[],"mappings":";AAAA,sCAAsC;;;;;;;;;;;;;;;;;;;;;;;;;;AAEtC,iDAAmC;AACnC,0DAA4C;AAC5C,mDAA+C;AAE/C;;;;GAIG;AACH,MAAa,QAAQ;IAUnB,YAAY,OAAe;QAP3B,WAAM,GAAW,SAAS,CAAC,MAAM,CAAC;QAClC,kBAAa,GAAa,EAAE,CAAC;QAC7B,iBAAY,GAAW,EAAE,CAAC;QAC1B,WAAM,GAAW,KAAK,CAAC;QACvB,eAAU,GAAW,EAAE,CAAC;QACxB,OAAE,GAAY,IAAI,CAAC;QA0DnB;;;;;WAKG;QACH,cAAS,GAAG,MAAM,CAAC,SAAS,CAAC,SAAS,CAAC,IAAI,CAAC,CAAC;QA0Q7C;;;;;WAKG;QACH,eAAU,GAAG,MAAM,CAAC,UAAU,CAAC;QA7U7B,IAAI,CAAC,OAAO,GAAG,OAAO,CAAC;QAEvB,MAAM,MAAM,GAAG,SAAS,CAAC,gBAAgB,CAAC,IAAI,CAAC,OAAO,CAAC,CAAC;QAExD,IAAI,MAAM,EAAE,CAAC;YACX,IAAI,CAAC,YAAY,GAAG,MAAM,CAAC,CAAC,CAAC,CAAC,OAAO,CAAC,GAAG,EAAE,EAAE,CAAC,CAAC;YAC/C,IAAI,CAAC,UAAU,GAAG,QAAQ,CAAC,IAAI,CAAC,YAAY,EAAE,EAAE,CAAC,CAAC;YAClD,IAAI,CAAC,MAAM,GAAG,IAAI,IAAI,CAAC,UAAU,EAAE,CAAC;YAEpC,IAAI,IAAI,CAAC,UAAU,GAAG,CAAC,IAAI,IAAI,CAAC,UAAU,GAAG,SAAS,CAAC,IAAI,EAAE,CAAC;gBAC5D,MAAM,IAAI,4BAAY,CAAC,sBAAsB,CAAC,CAAC;YACjD,CAAC;YAED,OAAO,GAAG,OAAO,CAAC,OAAO,CAAC,SAAS,CAAC,gBAAgB,EAAE,EAAE,CAAC,CAAC;QAC5D,CAAC;QAED,IAAI,CAAC,kBAAkB,GAAG,OAAO,CAAC;QAElC,IAAI,CAAC,aAAa,GAAG,IAAI,CAAC,KAAK,CAAC,OAAO,CAAC,CAAC;IAC3C,CAAC;IAED,MAAM,CAAC,OAAO,CAAC,OAAe;QAC5B,IAAI,CAAC;YACH,kCAAkC;YAClC,IAAI,QAAQ,CAAC,OAAO,CAAC,CAAC;YAEtB,OAAO,IAAI,CAAC;QACd,CAAC;QAAC,OAAO,CAAC,EAAE,CAAC;YACX,OAAO,KAAK,CAAC;QACf,CAAC;IACH,CAAC;IAED;;OAEG;IACH,KAAK,CAAC,OAAe;QACnB,MAAM,MAAM,GAAG,OAAO,CAAC,KAAK,CAAC,GAAG,CAAC,CAAC;QAElC,IAAI,CAAC,OAAO,CAAC,KAAK,CAAC,SAAS,CAAC,UAAU,CAAC,EAAE,CAAC;YACzC,MAAM,IAAI,4BAAY,CAAC,uBAAuB,CAAC,CAAC;QAClD,CAAC;QAED,OAAO,MAAM,CAAC;IAChB,CAAC;IAED;;;;;OAKG;IACH,WAAW;QACT,OAAO,IAAI,CAAC,aAAa,CAAC,GAAG,CAAC,CAAC,IAAI,EAAE,EAAE,CAAC,QAAQ,CAAC,IAAI,EAAE,EAAE,CAAC,CAAC,CAAC,IAAI,CAAC,GAAG,CAAC,CAAC;IACxE,CAAC;IAUD;;;;;;OAMG;IACH,MAAM,CAAC,OAAO,CAAC,GAAW;QACxB,MAAM,MAAM,GAAG,GAAG,CAAC,OAAO,CAAC,IAAI,EAAE,EAAE,CAAC,CAAC,QAAQ,CAAC,CAAC,EAAE,GAAG,CAAC,CAAC;QACtD,MAAM,MAAM,GAAG,EAAE,CAAC;QAClB,IAAI,CAAC,CAAC;QAEN,KAAK,CAAC,GAAG,CAAC,EAAE,CAAC,GAAG,CAAC,EAAE,CAAC,IAAI,CAAC,EAAE,CAAC;YAC1B,MAAM,CAAC,GAAG,MAAM,CAAC,KAAK,CAAC,CAAC,EAAE,CAAC,GAAG,CAAC,CAAC,CAAC;YAEjC,MAAM,CAAC,IAAI,CAAC,QAAQ,CAAC,CAAC,EAAE,EAAE,CAAC,CAAC,CAAC;QAC/B,CAAC;QAED,OAAO,IAAI,QAAQ,CAAC,MAAM,CAAC,IAAI,CAAC,GAAG,CAAC,CAAC,CAAC;IACxC,CAAC;IAED;;;;;;OAMG;IACH,MAAM,CAAC,WAAW,CAAC,OAAe;QAChC,OAAO,QAAQ,CAAC,OAAO,CAAC,OAAO,CAAC,QAAQ,CAAC,EAAE,CAAC,CAAC,CAAC;IAChD,CAAC;IAED;;;;;;;;;OASG;IACH,MAAM,CAAC,QAAQ,CAAC,eAAuB;QACrC,6CAA6C;QAC7C,MAAM,MAAM,GAAG,eAAe,CAAC,OAAO,CAAC,uBAAuB,EAAE,EAAE,CAAC,CAAC;QAEpE,MAAM,OAAO,GAAG,MAAM,CAAC,KAAK,CAAC,GAAG,CAAC,CAAC,OAAO,EAAE,CAAC,IAAI,CAAC,GAAG,CAAC,CAAC;QAEtD,OAAO,IAAI,QAAQ,CAAC,OAAO,CAAC,CAAC;IAC/B,CAAC;IAED;;;;;OAKG;IACH,KAAK;QACH,OAAO,IAAI,CAAC,aAAa,CAAC,GAAG,CAAC,CAAC,IAAI,EAAE,EAAE,CAAC,MAAM,CAAC,iBAAiB,CAAC,IAAI,CAAC,CAAC,CAAC,IAAI,CAAC,GAAG,CAAC,CAAC;IACpF,CAAC;IAED;;;;;OAKG;IACH,OAAO;QACL,OAAO,IAAI,CAAC,aAAa,CAAC,GAAG,CAAC,CAAC,IAAI,EAAE,EAAE,CAAC,QAAQ,CAAC,IAAI,EAAE,EAAE,CAAC,CAAC,CAAC;IAC9D,CAAC;IAED;;;;;OAKG;IACH,QAAQ;QACN,MAAM,MAAM,GAAG,EAAE,CAAC;QAClB,IAAI,CAAC,CAAC;QAEN,KAAK,CAAC,GAAG,CAAC,EAAE,CAAC,GAAG,SAAS,CAAC,MAAM,EAAE,CAAC,IAAI,CAAC,EAAE,CAAC;YACzC,MAAM,CAAC,IAAI,CACT,GAAG,MAAM,CAAC,iBAAiB,CAAC,IAAI,CAAC,aAAa,CAAC,CAAC,CAAC,CAAC,GAAG,MAAM,CAAC,iBAAiB,CAC3E,IAAI,CAAC,aAAa,CAAC,CAAC,GAAG,CAAC,CAAC,CAC1B,EAAE,CACJ,CAAC;QACJ,CAAC;QAED,OAAO,MAAM,CAAC,IAAI,CAAC,GAAG,CAAC,CAAC;IAC1B,CAAC;IAED;;;;;OAKG;IACH,MAAM;QACJ,OAAO,MAAM,CAAC,KAAK,IAAI,CAAC,aAAa,CAAC,GAAG,CAAC,CAAC,CAAC,EAAE,EAAE,CAAC,MAAM,CAAC,iBAAiB,CAAC,CAAC,CAAC,CAAC,CAAC,IAAI,CAAC,EAAE,CAAC,EAAE,CAAC,CAAC;IAC5F,CAAC;IAED;;;;;OAKG;IACH,aAAa;QACX,OAAO,MAAM,CAAC,KAAK,IAAI,CAAC,IAAI,EAAE,GAAG,GAAG,CAAC,MAAM,CAAC,SAAS,CAAC,IAAI,GAAG,IAAI,CAAC,UAAU,CAAC,EAAE,CAAC,CAAC;IACnF,CAAC;IAED;;;;;;OAMG;IACH,YAAY;QACV,OAAO,QAAQ,CAAC,UAAU,CAAC,IAAI,CAAC,aAAa,EAAE,CAAC,CAAC;IACnD,CAAC;IAED;;;;;;OAMG;IACH,qBAAqB;QACnB,MAAM,MAAM,GAAG,MAAM,CAAC,GAAG,CAAC,CAAC;QAC3B,OAAO,QAAQ,CAAC,UAAU,CAAC,IAAI,CAAC,aAAa,EAAE,GAAG,MAAM,CAAC,CAAC;IAC5D,CAAC;IAED;;;;;OAKG;IACH,WAAW;QACT,OAAO,MAAM,CAAC,KAAK,IAAI,CAAC,IAAI,EAAE,GAAG,GAAG,CAAC,MAAM,CAAC,SAAS,CAAC,IAAI,GAAG,IAAI,CAAC,UAAU,CAAC,EAAE,CAAC,CAAC;IACnF,CAAC;IAED;;;;;;OAMG;IACH,UAAU;QACR,OAAO,QAAQ,CAAC,UAAU,CAAC,IAAI,CAAC,WAAW,EAAE,CAAC,CAAC;IACjD,CAAC;IAED;;;;;;OAMG;IACH,mBAAmB;QACjB,MAAM,MAAM,GAAG,MAAM,CAAC,GAAG,CAAC,CAAC;QAC3B,OAAO,QAAQ,CAAC,UAAU,CAAC,IAAI,CAAC,WAAW,EAAE,GAAG,MAAM,CAAC,CAAC;IAC1D,CAAC;IAED;;;;;;OAMG;IACH,MAAM,CAAC,UAAU,CAAC,MAAc;QAC9B,OAAO,QAAQ,CAAC,OAAO,CAAC,MAAM,CAAC,QAAQ,CAAC,EAAE,CAAC,CAAC,CAAC;IAC/C,CAAC;IAED;;;;;;OAMG;IACH,MAAM,CAAC,aAAa,CAAC,KAAoB;QACvC,IAAI,KAAK,CAAC,MAAM,KAAK,CAAC,EAAE,CAAC;YACvB,MAAM,IAAI,4BAAY,CAAC,wCAAwC,CAAC,CAAC;QACnE,CAAC;QAED,yDAAyD;QACzD,KAAK,IAAI,CAAC,GAAG,CAAC,EAAE,CAAC,GAAG,KAAK,CAAC,MAAM,EAAE,CAAC,EAAE,EAAE,CAAC;YACtC,IAAI,CAAC,MAAM,CAAC,SAAS,CAAC,KAAK,CAAC,CAAC,CAAC,CAAC,IAAI,KAAK,CAAC,CAAC,CAAC,GAAG,CAAC,IAAI,KAAK,CAAC,CAAC,CAAC,GAAG,GAAG,EAAE,CAAC;gBAClE,MAAM,IAAI,4BAAY,CAAC,8CAA8C,CAAC,CAAC;YACzE,CAAC;QACH,CAAC;QAE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\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ipv6.d.ts b/server/node_modules/ip-address/dist/ipv6.d.ts
new file mode 100644
index 0000000..2a7c7e0
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ipv6.d.ts
@@ -0,0 +1,428 @@
+import * as common from './common';
+import { Address4 } from './ipv4';
+interface SixToFourProperties {
+    prefix: string;
+    gateway: string;
+}
+interface TeredoProperties {
+    prefix: string;
+    server4: string;
+    client4: string;
+    flags: string;
+    coneNat: boolean;
+    microsoft: {
+        reserved: boolean;
+        universalLocal: boolean;
+        groupIndividual: boolean;
+        nonce: string;
+    };
+    udpPort: string;
+}
+/**
+ * Represents an IPv6 address
+ * @class Address6
+ * @param {string} address - An IPv6 address string
+ * @param {number} [groups=8] - How many octets to parse
+ * @example
+ * var address = new Address6('2001::/32');
+ */
+export declare class Address6 {
+    address4?: Address4;
+    address: string;
+    addressMinusSuffix: string;
+    elidedGroups?: number;
+    elisionBegin?: number;
+    elisionEnd?: number;
+    groups: number;
+    parsedAddress4?: string;
+    parsedAddress: string[];
+    parsedSubnet: string;
+    subnet: string;
+    subnetMask: number;
+    v4: boolean;
+    zone: string;
+    constructor(address: string, optionalGroups?: number);
+    static isValid(address: string): boolean;
+    /**
+     * Convert a BigInt to a v6 address object
+     * @memberof Address6
+     * @static
+     * @param {bigint} bigInt - a BigInt to convert
+     * @returns {Address6}
+     * @example
+     * var bigInt = BigInt('1000000000000');
+     * var address = Address6.fromBigInt(bigInt);
+     * address.correctForm(); // '::e8:d4a5:1000'
+     */
+    static fromBigInt(bigInt: bigint): Address6;
+    /**
+     * Convert a URL (with optional port number) to an address object
+     * @memberof Address6
+     * @static
+     * @param {string} url - a URL with optional port number
+     * @example
+     * var addressAndPort = Address6.fromURL('http://[ffff::]:8080/foo/');
+     * addressAndPort.address.correctForm(); // 'ffff::'
+     * addressAndPort.port; // 8080
+     */
+    static fromURL(url: string): {
+        error: string;
+        address: null;
+        port: null;
+    } | {
+        address: Address6;
+        port: number | null;
+        error?: undefined;
+    };
+    /**
+     * Create an IPv6-mapped address given an IPv4 address
+     * @memberof Address6
+     * @static
+     * @param {string} address - An IPv4 address string
+     * @returns {Address6}
+     * @example
+     * var address = Address6.fromAddress4('192.168.0.1');
+     * address.correctForm(); // '::ffff:c0a8:1'
+     * address.to4in6(); // '::ffff:192.168.0.1'
+     */
+    static fromAddress4(address: string): Address6;
+    /**
+     * Return an address from ip6.arpa form
+     * @memberof Address6
+     * @static
+     * @param {string} arpaFormAddress - an 'ip6.arpa' form address
+     * @returns {Adress6}
+     * @example
+     * var address = Address6.fromArpa(e.f.f.f.3.c.2.6.f.f.f.e.6.6.8.e.1.0.6.7.9.4.e.c.0.0.0.0.1.0.0.2.ip6.arpa.)
+     * address.correctForm(); // '2001:0:ce49:7601:e866:efff:62c3:fffe'
+     */
+    static fromArpa(arpaFormAddress: string): Address6;
+    /**
+     * Return the Microsoft UNC transcription of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String} the Microsoft UNC transcription of the address
+     */
+    microsoftTranscription(): string;
+    /**
+     * Return the first n bits of the address, defaulting to the subnet mask
+     * @memberof Address6
+     * @instance
+     * @param {number} [mask=subnet] - the number of bits to mask
+     * @returns {String} the first n bits of the address as a string
+     */
+    mask(mask?: number): string;
+    /**
+     * Return the number of possible subnets of a given size in the address
+     * @memberof Address6
+     * @instance
+     * @param {number} [subnetSize=128] - the subnet size
+     * @returns {String}
+     */
+    possibleSubnets(subnetSize?: number): string;
+    /**
+     * Helper function getting start address.
+     * @memberof Address6
+     * @instance
+     * @returns {bigint}
+     */
+    _startAddress(): bigint;
+    /**
+     * The first address in the range given by this address' subnet
+     * Often referred to as the Network Address.
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    startAddress(): Address6;
+    /**
+     * The first host address in the range given by this address's subnet ie
+     * the first address after the Network Address
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    startAddressExclusive(): Address6;
+    /**
+     * Helper function getting end address.
+     * @memberof Address6
+     * @instance
+     * @returns {bigint}
+     */
+    _endAddress(): bigint;
+    /**
+     * The last address in the range given by this address' subnet
+     * Often referred to as the Broadcast
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    endAddress(): Address6;
+    /**
+     * The last host address in the range given by this address's subnet ie
+     * the last address prior to the Broadcast Address
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    endAddressExclusive(): Address6;
+    /**
+     * Return the scope of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getScope(): string;
+    /**
+     * Return the type of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getType(): string;
+    /**
+     * Return the bits in the given range as a BigInt
+     * @memberof Address6
+     * @instance
+     * @returns {bigint}
+     */
+    getBits(start: number, end: number): bigint;
+    /**
+     * Return the bits in the given range as a base-2 string
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getBitsBase2(start: number, end: number): string;
+    /**
+     * Return the bits in the given range as a base-16 string
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getBitsBase16(start: number, end: number): string;
+    /**
+     * Return the bits that are set past the subnet mask length
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getBitsPastSubnet(): string;
+    /**
+     * Return the reversed ip6.arpa form of the address
+     * @memberof Address6
+     * @param {Object} options
+     * @param {boolean} options.omitSuffix - omit the "ip6.arpa" suffix
+     * @instance
+     * @returns {String}
+     */
+    reverseForm(options?: common.ReverseFormOptions): string;
+    /**
+     * Return the correct form of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    correctForm(): string;
+    /**
+     * Return a zero-padded base-2 string representation of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     * @example
+     * var address = new Address6('2001:4860:4001:803::1011');
+     * address.binaryZeroPad();
+     * // '0010000000000001010010000110000001000000000000010000100000000011
+     * //  0000000000000000000000000000000000000000000000000001000000010001'
+     */
+    binaryZeroPad(): string;
+    parse4in6(address: string): string;
+    parse(address: string): string[];
+    /**
+     * Return the canonical form of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    canonicalForm(): string;
+    /**
+     * Return the decimal form of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    decimal(): string;
+    /**
+     * Return the address as a BigInt
+     * @memberof Address6
+     * @instance
+     * @returns {bigint}
+     */
+    bigInt(): bigint;
+    /**
+     * Return the last two groups of this address as an IPv4 address string
+     * @memberof Address6
+     * @instance
+     * @returns {Address4}
+     * @example
+     * var address = new Address6('2001:4860:4001::1825:bf11');
+     * address.to4().correctForm(); // '24.37.191.17'
+     */
+    to4(): Address4;
+    /**
+     * Return the v4-in-v6 form of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    to4in6(): string;
+    /**
+     * Return an object containing the Teredo properties of the address
+     * @memberof Address6
+     * @instance
+     * @returns {Object}
+     */
+    inspectTeredo(): TeredoProperties;
+    /**
+     * Return an object containing the 6to4 properties of the address
+     * @memberof Address6
+     * @instance
+     * @returns {Object}
+     */
+    inspect6to4(): SixToFourProperties;
+    /**
+     * Return a v6 6to4 address from a v6 v4inv6 address
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    to6to4(): Address6 | null;
+    /**
+     * Return a byte array
+     * @memberof Address6
+     * @instance
+     * @returns {Array}
+     */
+    toByteArray(): number[];
+    /**
+     * Return an unsigned byte array
+     * @memberof Address6
+     * @instance
+     * @returns {Array}
+     */
+    toUnsignedByteArray(): number[];
+    /**
+     * Convert a byte array to an Address6 object
+     * @memberof Address6
+     * @static
+     * @returns {Address6}
+     */
+    static fromByteArray(bytes: Array<any>): Address6;
+    /**
+     * Convert an unsigned byte array to an Address6 object
+     * @memberof Address6
+     * @static
+     * @returns {Address6}
+     */
+    static fromUnsignedByteArray(bytes: Array<any>): Address6;
+    /**
+     * Returns true if the given address is in the subnet of the current address
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isInSubnet: typeof common.isInSubnet;
+    /**
+     * Returns true if the address is correct, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isCorrect: (this: Address4 | Address6) => boolean;
+    /**
+     * Returns true if the address is in the canonical form, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isCanonical(): boolean;
+    /**
+     * Returns true if the address is a link local address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isLinkLocal(): boolean;
+    /**
+     * Returns true if the address is a multicast address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isMulticast(): boolean;
+    /**
+     * Returns true if the address is a v4-in-v6 address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    is4(): boolean;
+    /**
+     * Returns true if the address is a Teredo address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isTeredo(): boolean;
+    /**
+     * Returns true if the address is a 6to4 address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    is6to4(): boolean;
+    /**
+     * Returns true if the address is a loopback address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isLoopback(): boolean;
+    /**
+     * @returns {String} the address in link form with a default port of 80
+     */
+    href(optionalPort?: number | string): string;
+    /**
+     * @returns {String} a link suitable for conveying the address via a URL hash
+     */
+    link(options?: {
+        className?: string;
+        prefix?: string;
+        v4?: boolean;
+    }): string;
+    /**
+     * Groups an address
+     * @returns {String}
+     */
+    group(): string;
+    /**
+     * Generate a regular expression string that can be used to find or validate
+     * all variations of this address
+     * @memberof Address6
+     * @instance
+     * @param {boolean} substringSearch
+     * @returns {string}
+     */
+    regularExpressionString(this: Address6, substringSearch?: boolean): string;
+    /**
+     * Generate a regular expression that can be used to find or validate all
+     * variations of this address.
+     * @memberof Address6
+     * @instance
+     * @param {boolean} substringSearch
+     * @returns {RegExp}
+     */
+    regularExpression(this: Address6, substringSearch?: boolean): RegExp;
+}
+export {};
+//# sourceMappingURL=ipv6.d.ts.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ipv6.d.ts.map b/server/node_modules/ip-address/dist/ipv6.d.ts.map
new file mode 100644
index 0000000..37ead6a
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ipv6.d.ts.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ipv6.js b/server/node_modules/ip-address/dist/ipv6.js
new file mode 100644
index 0000000..5f88ab6
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ipv6.js
@@ -0,0 +1,1003 @@
+"use strict";
+/* eslint-disable prefer-destructuring */
+/* eslint-disable no-param-reassign */
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.Address6 = void 0;
+const common = __importStar(require("./common"));
+const constants4 = __importStar(require("./v4/constants"));
+const constants6 = __importStar(require("./v6/constants"));
+const helpers = __importStar(require("./v6/helpers"));
+const ipv4_1 = require("./ipv4");
+const regular_expressions_1 = require("./v6/regular-expressions");
+const address_error_1 = require("./address-error");
+const common_1 = require("./common");
+function assert(condition) {
+    if (!condition) {
+        throw new Error('Assertion failed.');
+    }
+}
+function addCommas(number) {
+    const r = /(\d+)(\d{3})/;
+    while (r.test(number)) {
+        number = number.replace(r, '$1,$2');
+    }
+    return number;
+}
+function spanLeadingZeroes4(n) {
+    n = n.replace(/^(0{1,})([1-9]+)$/, '<span class="parse-error">$1</span>$2');
+    n = n.replace(/^(0{1,})(0)$/, '<span class="parse-error">$1</span>$2');
+    return n;
+}
+/*
+ * A helper function to compact an array
+ */
+function compact(address, slice) {
+    const s1 = [];
+    const s2 = [];
+    let i;
+    for (i = 0; i < address.length; i++) {
+        if (i < slice[0]) {
+            s1.push(address[i]);
+        }
+        else if (i > slice[1]) {
+            s2.push(address[i]);
+        }
+    }
+    return s1.concat(['compact']).concat(s2);
+}
+function paddedHex(octet) {
+    return parseInt(octet, 16).toString(16).padStart(4, '0');
+}
+function unsignByte(b) {
+    // eslint-disable-next-line no-bitwise
+    return b & 0xff;
+}
+/**
+ * Represents an IPv6 address
+ * @class Address6
+ * @param {string} address - An IPv6 address string
+ * @param {number} [groups=8] - How many octets to parse
+ * @example
+ * var address = new Address6('2001::/32');
+ */
+class Address6 {
+    constructor(address, optionalGroups) {
+        this.addressMinusSuffix = '';
+        this.parsedSubnet = '';
+        this.subnet = '/128';
+        this.subnetMask = 128;
+        this.v4 = false;
+        this.zone = '';
+        // #region Attributes
+        /**
+         * Returns true if the given address is in the subnet of the current address
+         * @memberof Address6
+         * @instance
+         * @returns {boolean}
+         */
+        this.isInSubnet = common.isInSubnet;
+        /**
+         * Returns true if the address is correct, false otherwise
+         * @memberof Address6
+         * @instance
+         * @returns {boolean}
+         */
+        this.isCorrect = common.isCorrect(constants6.BITS);
+        if (optionalGroups === undefined) {
+            this.groups = constants6.GROUPS;
+        }
+        else {
+            this.groups = optionalGroups;
+        }
+        this.address = address;
+        const subnet = constants6.RE_SUBNET_STRING.exec(address);
+        if (subnet) {
+            this.parsedSubnet = subnet[0].replace('/', '');
+            this.subnetMask = parseInt(this.parsedSubnet, 10);
+            this.subnet = `/${this.subnetMask}`;
+            if (Number.isNaN(this.subnetMask) ||
+                this.subnetMask < 0 ||
+                this.subnetMask > constants6.BITS) {
+                throw new address_error_1.AddressError('Invalid subnet mask.');
+            }
+            address = address.replace(constants6.RE_SUBNET_STRING, '');
+        }
+        else if (/\//.test(address)) {
+            throw new address_error_1.AddressError('Invalid subnet mask.');
+        }
+        const zone = constants6.RE_ZONE_STRING.exec(address);
+        if (zone) {
+            this.zone = zone[0];
+            address = address.replace(constants6.RE_ZONE_STRING, '');
+        }
+        this.addressMinusSuffix = address;
+        this.parsedAddress = this.parse(this.addressMinusSuffix);
+    }
+    static isValid(address) {
+        try {
+            // eslint-disable-next-line no-new
+            new Address6(address);
+            return true;
+        }
+        catch (e) {
+            return false;
+        }
+    }
+    /**
+     * Convert a BigInt to a v6 address object
+     * @memberof Address6
+     * @static
+     * @param {bigint} bigInt - a BigInt to convert
+     * @returns {Address6}
+     * @example
+     * var bigInt = BigInt('1000000000000');
+     * var address = Address6.fromBigInt(bigInt);
+     * address.correctForm(); // '::e8:d4a5:1000'
+     */
+    static fromBigInt(bigInt) {
+        const hex = bigInt.toString(16).padStart(32, '0');
+        const groups = [];
+        let i;
+        for (i = 0; i < constants6.GROUPS; i++) {
+            groups.push(hex.slice(i * 4, (i + 1) * 4));
+        }
+        return new Address6(groups.join(':'));
+    }
+    /**
+     * Convert a URL (with optional port number) to an address object
+     * @memberof Address6
+     * @static
+     * @param {string} url - a URL with optional port number
+     * @example
+     * var addressAndPort = Address6.fromURL('http://[ffff::]:8080/foo/');
+     * addressAndPort.address.correctForm(); // 'ffff::'
+     * addressAndPort.port; // 8080
+     */
+    static fromURL(url) {
+        let host;
+        let port = null;
+        let result;
+        // If we have brackets parse them and find a port
+        if (url.indexOf('[') !== -1 && url.indexOf(']:') !== -1) {
+            result = constants6.RE_URL_WITH_PORT.exec(url);
+            if (result === null) {
+                return {
+                    error: 'failed to parse address with port',
+                    address: null,
+                    port: null,
+                };
+            }
+            host = result[1];
+            port = result[2];
+            // If there's a URL extract the address
+        }
+        else if (url.indexOf('/') !== -1) {
+            // Remove the protocol prefix
+            url = url.replace(/^[a-z0-9]+:\/\//, '');
+            // Parse the address
+            result = constants6.RE_URL.exec(url);
+            if (result === null) {
+                return {
+                    error: 'failed to parse address from URL',
+                    address: null,
+                    port: null,
+                };
+            }
+            host = result[1];
+            // Otherwise just assign the URL to the host and let the library parse it
+        }
+        else {
+            host = url;
+        }
+        // If there's a port convert it to an integer
+        if (port) {
+            port = parseInt(port, 10);
+            // squelch out of range ports
+            if (port < 0 || port > 65536) {
+                port = null;
+            }
+        }
+        else {
+            // Standardize `undefined` to `null`
+            port = null;
+        }
+        return {
+            address: new Address6(host),
+            port,
+        };
+    }
+    /**
+     * Create an IPv6-mapped address given an IPv4 address
+     * @memberof Address6
+     * @static
+     * @param {string} address - An IPv4 address string
+     * @returns {Address6}
+     * @example
+     * var address = Address6.fromAddress4('192.168.0.1');
+     * address.correctForm(); // '::ffff:c0a8:1'
+     * address.to4in6(); // '::ffff:192.168.0.1'
+     */
+    static fromAddress4(address) {
+        const address4 = new ipv4_1.Address4(address);
+        const mask6 = constants6.BITS - (constants4.BITS - address4.subnetMask);
+        return new Address6(`::ffff:${address4.correctForm()}/${mask6}`);
+    }
+    /**
+     * Return an address from ip6.arpa form
+     * @memberof Address6
+     * @static
+     * @param {string} arpaFormAddress - an 'ip6.arpa' form address
+     * @returns {Adress6}
+     * @example
+     * var address = Address6.fromArpa(e.f.f.f.3.c.2.6.f.f.f.e.6.6.8.e.1.0.6.7.9.4.e.c.0.0.0.0.1.0.0.2.ip6.arpa.)
+     * address.correctForm(); // '2001:0:ce49:7601:e866:efff:62c3:fffe'
+     */
+    static fromArpa(arpaFormAddress) {
+        // remove ending ".ip6.arpa." or just "."
+        let address = arpaFormAddress.replace(/(\.ip6\.arpa)?\.$/, '');
+        const semicolonAmount = 7;
+        // correct ip6.arpa form with ending removed will be 63 characters
+        if (address.length !== 63) {
+            throw new address_error_1.AddressError("Invalid 'ip6.arpa' form.");
+        }
+        const parts = address.split('.').reverse();
+        for (let i = semicolonAmount; i > 0; i--) {
+            const insertIndex = i * 4;
+            parts.splice(insertIndex, 0, ':');
+        }
+        address = parts.join('');
+        return new Address6(address);
+    }
+    /**
+     * Return the Microsoft UNC transcription of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String} the Microsoft UNC transcription of the address
+     */
+    microsoftTranscription() {
+        return `${this.correctForm().replace(/:/g, '-')}.ipv6-literal.net`;
+    }
+    /**
+     * Return the first n bits of the address, defaulting to the subnet mask
+     * @memberof Address6
+     * @instance
+     * @param {number} [mask=subnet] - the number of bits to mask
+     * @returns {String} the first n bits of the address as a string
+     */
+    mask(mask = this.subnetMask) {
+        return this.getBitsBase2(0, mask);
+    }
+    /**
+     * Return the number of possible subnets of a given size in the address
+     * @memberof Address6
+     * @instance
+     * @param {number} [subnetSize=128] - the subnet size
+     * @returns {String}
+     */
+    // TODO: probably useful to have a numeric version of this too
+    possibleSubnets(subnetSize = 128) {
+        const availableBits = constants6.BITS - this.subnetMask;
+        const subnetBits = Math.abs(subnetSize - constants6.BITS);
+        const subnetPowers = availableBits - subnetBits;
+        if (subnetPowers < 0) {
+            return '0';
+        }
+        return addCommas((BigInt('2') ** BigInt(subnetPowers)).toString(10));
+    }
+    /**
+     * Helper function getting start address.
+     * @memberof Address6
+     * @instance
+     * @returns {bigint}
+     */
+    _startAddress() {
+        return BigInt(`0b${this.mask() + '0'.repeat(constants6.BITS - this.subnetMask)}`);
+    }
+    /**
+     * The first address in the range given by this address' subnet
+     * Often referred to as the Network Address.
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    startAddress() {
+        return Address6.fromBigInt(this._startAddress());
+    }
+    /**
+     * The first host address in the range given by this address's subnet ie
+     * the first address after the Network Address
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    startAddressExclusive() {
+        const adjust = BigInt('1');
+        return Address6.fromBigInt(this._startAddress() + adjust);
+    }
+    /**
+     * Helper function getting end address.
+     * @memberof Address6
+     * @instance
+     * @returns {bigint}
+     */
+    _endAddress() {
+        return BigInt(`0b${this.mask() + '1'.repeat(constants6.BITS - this.subnetMask)}`);
+    }
+    /**
+     * The last address in the range given by this address' subnet
+     * Often referred to as the Broadcast
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    endAddress() {
+        return Address6.fromBigInt(this._endAddress());
+    }
+    /**
+     * The last host address in the range given by this address's subnet ie
+     * the last address prior to the Broadcast Address
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    endAddressExclusive() {
+        const adjust = BigInt('1');
+        return Address6.fromBigInt(this._endAddress() - adjust);
+    }
+    /**
+     * Return the scope of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getScope() {
+        let scope = constants6.SCOPES[parseInt(this.getBits(12, 16).toString(10), 10)];
+        if (this.getType() === 'Global unicast' && scope !== 'Link local') {
+            scope = 'Global';
+        }
+        return scope || 'Unknown';
+    }
+    /**
+     * Return the type of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getType() {
+        for (const subnet of Object.keys(constants6.TYPES)) {
+            if (this.isInSubnet(new Address6(subnet))) {
+                return constants6.TYPES[subnet];
+            }
+        }
+        return 'Global unicast';
+    }
+    /**
+     * Return the bits in the given range as a BigInt
+     * @memberof Address6
+     * @instance
+     * @returns {bigint}
+     */
+    getBits(start, end) {
+        return BigInt(`0b${this.getBitsBase2(start, end)}`);
+    }
+    /**
+     * Return the bits in the given range as a base-2 string
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getBitsBase2(start, end) {
+        return this.binaryZeroPad().slice(start, end);
+    }
+    /**
+     * Return the bits in the given range as a base-16 string
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getBitsBase16(start, end) {
+        const length = end - start;
+        if (length % 4 !== 0) {
+            throw new Error('Length of bits to retrieve must be divisible by four');
+        }
+        return this.getBits(start, end)
+            .toString(16)
+            .padStart(length / 4, '0');
+    }
+    /**
+     * Return the bits that are set past the subnet mask length
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    getBitsPastSubnet() {
+        return this.getBitsBase2(this.subnetMask, constants6.BITS);
+    }
+    /**
+     * Return the reversed ip6.arpa form of the address
+     * @memberof Address6
+     * @param {Object} options
+     * @param {boolean} options.omitSuffix - omit the "ip6.arpa" suffix
+     * @instance
+     * @returns {String}
+     */
+    reverseForm(options) {
+        if (!options) {
+            options = {};
+        }
+        const characters = Math.floor(this.subnetMask / 4);
+        const reversed = this.canonicalForm()
+            .replace(/:/g, '')
+            .split('')
+            .slice(0, characters)
+            .reverse()
+            .join('.');
+        if (characters > 0) {
+            if (options.omitSuffix) {
+                return reversed;
+            }
+            return `${reversed}.ip6.arpa.`;
+        }
+        if (options.omitSuffix) {
+            return '';
+        }
+        return 'ip6.arpa.';
+    }
+    /**
+     * Return the correct form of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    correctForm() {
+        let i;
+        let groups = [];
+        let zeroCounter = 0;
+        const zeroes = [];
+        for (i = 0; i < this.parsedAddress.length; i++) {
+            const value = parseInt(this.parsedAddress[i], 16);
+            if (value === 0) {
+                zeroCounter++;
+            }
+            if (value !== 0 && zeroCounter > 0) {
+                if (zeroCounter > 1) {
+                    zeroes.push([i - zeroCounter, i - 1]);
+                }
+                zeroCounter = 0;
+            }
+        }
+        // Do we end with a string of zeroes?
+        if (zeroCounter > 1) {
+            zeroes.push([this.parsedAddress.length - zeroCounter, this.parsedAddress.length - 1]);
+        }
+        const zeroLengths = zeroes.map((n) => n[1] - n[0] + 1);
+        if (zeroes.length > 0) {
+            const index = zeroLengths.indexOf(Math.max(...zeroLengths));
+            groups = compact(this.parsedAddress, zeroes[index]);
+        }
+        else {
+            groups = this.parsedAddress;
+        }
+        for (i = 0; i < groups.length; i++) {
+            if (groups[i] !== 'compact') {
+                groups[i] = parseInt(groups[i], 16).toString(16);
+            }
+        }
+        let correct = groups.join(':');
+        correct = correct.replace(/^compact$/, '::');
+        correct = correct.replace(/(^compact)|(compact$)/, ':');
+        correct = correct.replace(/compact/, '');
+        return correct;
+    }
+    /**
+     * Return a zero-padded base-2 string representation of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     * @example
+     * var address = new Address6('2001:4860:4001:803::1011');
+     * address.binaryZeroPad();
+     * // '0010000000000001010010000110000001000000000000010000100000000011
+     * //  0000000000000000000000000000000000000000000000000001000000010001'
+     */
+    binaryZeroPad() {
+        return this.bigInt().toString(2).padStart(constants6.BITS, '0');
+    }
+    // TODO: Improve the semantics of this helper function
+    parse4in6(address) {
+        const groups = address.split(':');
+        const lastGroup = groups.slice(-1)[0];
+        const address4 = lastGroup.match(constants4.RE_ADDRESS);
+        if (address4) {
+            this.parsedAddress4 = address4[0];
+            this.address4 = new ipv4_1.Address4(this.parsedAddress4);
+            for (let i = 0; i < this.address4.groups; i++) {
+                if (/^0[0-9]+/.test(this.address4.parsedAddress[i])) {
+                    throw new address_error_1.AddressError("IPv4 addresses can't have leading zeroes.", address.replace(constants4.RE_ADDRESS, this.address4.parsedAddress.map(spanLeadingZeroes4).join('.')));
+                }
+            }
+            this.v4 = true;
+            groups[groups.length - 1] = this.address4.toGroup6();
+            address = groups.join(':');
+        }
+        return address;
+    }
+    // TODO: Make private?
+    parse(address) {
+        address = this.parse4in6(address);
+        const badCharacters = address.match(constants6.RE_BAD_CHARACTERS);
+        if (badCharacters) {
+            throw new address_error_1.AddressError(`Bad character${badCharacters.length > 1 ? 's' : ''} detected in address: ${badCharacters.join('')}`, address.replace(constants6.RE_BAD_CHARACTERS, '<span class="parse-error">$1</span>'));
+        }
+        const badAddress = address.match(constants6.RE_BAD_ADDRESS);
+        if (badAddress) {
+            throw new address_error_1.AddressError(`Address failed regex: ${badAddress.join('')}`, address.replace(constants6.RE_BAD_ADDRESS, '<span class="parse-error">$1</span>'));
+        }
+        let groups = [];
+        const halves = address.split('::');
+        if (halves.length === 2) {
+            let first = halves[0].split(':');
+            let last = halves[1].split(':');
+            if (first.length === 1 && first[0] === '') {
+                first = [];
+            }
+            if (last.length === 1 && last[0] === '') {
+                last = [];
+            }
+            const remaining = this.groups - (first.length + last.length);
+            if (!remaining) {
+                throw new address_error_1.AddressError('Error parsing groups');
+            }
+            this.elidedGroups = remaining;
+            this.elisionBegin = first.length;
+            this.elisionEnd = first.length + this.elidedGroups;
+            groups = groups.concat(first);
+            for (let i = 0; i < remaining; i++) {
+                groups.push('0');
+            }
+            groups = groups.concat(last);
+        }
+        else if (halves.length === 1) {
+            groups = address.split(':');
+            this.elidedGroups = 0;
+        }
+        else {
+            throw new address_error_1.AddressError('Too many :: groups found');
+        }
+        groups = groups.map((group) => parseInt(group, 16).toString(16));
+        if (groups.length !== this.groups) {
+            throw new address_error_1.AddressError('Incorrect number of groups found');
+        }
+        return groups;
+    }
+    /**
+     * Return the canonical form of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    canonicalForm() {
+        return this.parsedAddress.map(paddedHex).join(':');
+    }
+    /**
+     * Return the decimal form of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    decimal() {
+        return this.parsedAddress.map((n) => parseInt(n, 16).toString(10).padStart(5, '0')).join(':');
+    }
+    /**
+     * Return the address as a BigInt
+     * @memberof Address6
+     * @instance
+     * @returns {bigint}
+     */
+    bigInt() {
+        return BigInt(`0x${this.parsedAddress.map(paddedHex).join('')}`);
+    }
+    /**
+     * Return the last two groups of this address as an IPv4 address string
+     * @memberof Address6
+     * @instance
+     * @returns {Address4}
+     * @example
+     * var address = new Address6('2001:4860:4001::1825:bf11');
+     * address.to4().correctForm(); // '24.37.191.17'
+     */
+    to4() {
+        const binary = this.binaryZeroPad().split('');
+        return ipv4_1.Address4.fromHex(BigInt(`0b${binary.slice(96, 128).join('')}`).toString(16));
+    }
+    /**
+     * Return the v4-in-v6 form of the address
+     * @memberof Address6
+     * @instance
+     * @returns {String}
+     */
+    to4in6() {
+        const address4 = this.to4();
+        const address6 = new Address6(this.parsedAddress.slice(0, 6).join(':'), 6);
+        const correct = address6.correctForm();
+        let infix = '';
+        if (!/:$/.test(correct)) {
+            infix = ':';
+        }
+        return correct + infix + address4.address;
+    }
+    /**
+     * Return an object containing the Teredo properties of the address
+     * @memberof Address6
+     * @instance
+     * @returns {Object}
+     */
+    inspectTeredo() {
+        /*
+        - Bits 0 to 31 are set to the Teredo prefix (normally 2001:0000::/32).
+        - Bits 32 to 63 embed the primary IPv4 address of the Teredo server that
+          is used.
+        - Bits 64 to 79 can be used to define some flags. Currently only the
+          higher order bit is used; it is set to 1 if the Teredo client is
+          located behind a cone NAT, 0 otherwise. For Microsoft's Windows Vista
+          and Windows Server 2008 implementations, more bits are used. In those
+          implementations, the format for these 16 bits is "CRAAAAUG AAAAAAAA",
+          where "C" remains the "Cone" flag. The "R" bit is reserved for future
+          use. The "U" bit is for the Universal/Local flag (set to 0). The "G" bit
+          is Individual/Group flag (set to 0). The A bits are set to a 12-bit
+          randomly generated number chosen by the Teredo client to introduce
+          additional protection for the Teredo node against IPv6-based scanning
+          attacks.
+        - Bits 80 to 95 contains the obfuscated UDP port number. This is the
+          port number that is mapped by the NAT to the Teredo client with all
+          bits inverted.
+        - Bits 96 to 127 contains the obfuscated IPv4 address. This is the
+          public IPv4 address of the NAT with all bits inverted.
+        */
+        const prefix = this.getBitsBase16(0, 32);
+        const bitsForUdpPort = this.getBits(80, 96);
+        // eslint-disable-next-line no-bitwise
+        const udpPort = (bitsForUdpPort ^ BigInt('0xffff')).toString();
+        const server4 = ipv4_1.Address4.fromHex(this.getBitsBase16(32, 64));
+        const bitsForClient4 = this.getBits(96, 128);
+        // eslint-disable-next-line no-bitwise
+        const client4 = ipv4_1.Address4.fromHex((bitsForClient4 ^ BigInt('0xffffffff')).toString(16));
+        const flagsBase2 = this.getBitsBase2(64, 80);
+        const coneNat = (0, common_1.testBit)(flagsBase2, 15);
+        const reserved = (0, common_1.testBit)(flagsBase2, 14);
+        const groupIndividual = (0, common_1.testBit)(flagsBase2, 8);
+        const universalLocal = (0, common_1.testBit)(flagsBase2, 9);
+        const nonce = BigInt(`0b${flagsBase2.slice(2, 6) + flagsBase2.slice(8, 16)}`).toString(10);
+        return {
+            prefix: `${prefix.slice(0, 4)}:${prefix.slice(4, 8)}`,
+            server4: server4.address,
+            client4: client4.address,
+            flags: flagsBase2,
+            coneNat,
+            microsoft: {
+                reserved,
+                universalLocal,
+                groupIndividual,
+                nonce,
+            },
+            udpPort,
+        };
+    }
+    /**
+     * Return an object containing the 6to4 properties of the address
+     * @memberof Address6
+     * @instance
+     * @returns {Object}
+     */
+    inspect6to4() {
+        /*
+        - Bits 0 to 15 are set to the 6to4 prefix (2002::/16).
+        - Bits 16 to 48 embed the IPv4 address of the 6to4 gateway that is used.
+        */
+        const prefix = this.getBitsBase16(0, 16);
+        const gateway = ipv4_1.Address4.fromHex(this.getBitsBase16(16, 48));
+        return {
+            prefix: prefix.slice(0, 4),
+            gateway: gateway.address,
+        };
+    }
+    /**
+     * Return a v6 6to4 address from a v6 v4inv6 address
+     * @memberof Address6
+     * @instance
+     * @returns {Address6}
+     */
+    to6to4() {
+        if (!this.is4()) {
+            return null;
+        }
+        const addr6to4 = [
+            '2002',
+            this.getBitsBase16(96, 112),
+            this.getBitsBase16(112, 128),
+            '',
+            '/16',
+        ].join(':');
+        return new Address6(addr6to4);
+    }
+    /**
+     * Return a byte array
+     * @memberof Address6
+     * @instance
+     * @returns {Array}
+     */
+    toByteArray() {
+        const valueWithoutPadding = this.bigInt().toString(16);
+        const leadingPad = '0'.repeat(valueWithoutPadding.length % 2);
+        const value = `${leadingPad}${valueWithoutPadding}`;
+        const bytes = [];
+        for (let i = 0, length = value.length; i < length; i += 2) {
+            bytes.push(parseInt(value.substring(i, i + 2), 16));
+        }
+        return bytes;
+    }
+    /**
+     * Return an unsigned byte array
+     * @memberof Address6
+     * @instance
+     * @returns {Array}
+     */
+    toUnsignedByteArray() {
+        return this.toByteArray().map(unsignByte);
+    }
+    /**
+     * Convert a byte array to an Address6 object
+     * @memberof Address6
+     * @static
+     * @returns {Address6}
+     */
+    static fromByteArray(bytes) {
+        return this.fromUnsignedByteArray(bytes.map(unsignByte));
+    }
+    /**
+     * Convert an unsigned byte array to an Address6 object
+     * @memberof Address6
+     * @static
+     * @returns {Address6}
+     */
+    static fromUnsignedByteArray(bytes) {
+        const BYTE_MAX = BigInt('256');
+        let result = BigInt('0');
+        let multiplier = BigInt('1');
+        for (let i = bytes.length - 1; i >= 0; i--) {
+            result += multiplier * BigInt(bytes[i].toString(10));
+            multiplier *= BYTE_MAX;
+        }
+        return Address6.fromBigInt(result);
+    }
+    /**
+     * Returns true if the address is in the canonical form, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isCanonical() {
+        return this.addressMinusSuffix === this.canonicalForm();
+    }
+    /**
+     * Returns true if the address is a link local address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isLinkLocal() {
+        // Zeroes are required, i.e. we can't check isInSubnet with 'fe80::/10'
+        if (this.getBitsBase2(0, 64) ===
+            '1111111010000000000000000000000000000000000000000000000000000000') {
+            return true;
+        }
+        return false;
+    }
+    /**
+     * Returns true if the address is a multicast address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isMulticast() {
+        return this.getType() === 'Multicast';
+    }
+    /**
+     * Returns true if the address is a v4-in-v6 address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    is4() {
+        return this.v4;
+    }
+    /**
+     * Returns true if the address is a Teredo address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isTeredo() {
+        return this.isInSubnet(new Address6('2001::/32'));
+    }
+    /**
+     * Returns true if the address is a 6to4 address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    is6to4() {
+        return this.isInSubnet(new Address6('2002::/16'));
+    }
+    /**
+     * Returns true if the address is a loopback address, false otherwise
+     * @memberof Address6
+     * @instance
+     * @returns {boolean}
+     */
+    isLoopback() {
+        return this.getType() === 'Loopback';
+    }
+    // #endregion
+    // #region HTML
+    /**
+     * @returns {String} the address in link form with a default port of 80
+     */
+    href(optionalPort) {
+        if (optionalPort === undefined) {
+            optionalPort = '';
+        }
+        else {
+            optionalPort = `:${optionalPort}`;
+        }
+        return `http://[${this.correctForm()}]${optionalPort}/`;
+    }
+    /**
+     * @returns {String} a link suitable for conveying the address via a URL hash
+     */
+    link(options) {
+        if (!options) {
+            options = {};
+        }
+        if (options.className === undefined) {
+            options.className = '';
+        }
+        if (options.prefix === undefined) {
+            options.prefix = '/#address=';
+        }
+        if (options.v4 === undefined) {
+            options.v4 = false;
+        }
+        let formFunction = this.correctForm;
+        if (options.v4) {
+            formFunction = this.to4in6;
+        }
+        const form = formFunction.call(this);
+        if (options.className) {
+            return `<a href="${options.prefix}${form}" class="${options.className}">${form}</a>`;
+        }
+        return `<a href="${options.prefix}${form}">${form}</a>`;
+    }
+    /**
+     * Groups an address
+     * @returns {String}
+     */
+    group() {
+        if (this.elidedGroups === 0) {
+            // The simple case
+            return helpers.simpleGroup(this.address).join(':');
+        }
+        assert(typeof this.elidedGroups === 'number');
+        assert(typeof this.elisionBegin === 'number');
+        // The elided case
+        const output = [];
+        const [left, right] = this.address.split('::');
+        if (left.length) {
+            output.push(...helpers.simpleGroup(left));
+        }
+        else {
+            output.push('');
+        }
+        const classes = ['hover-group'];
+        for (let i = this.elisionBegin; i < this.elisionBegin + this.elidedGroups; i++) {
+            classes.push(`group-${i}`);
+        }
+        output.push(`<span class="${classes.join(' ')}"></span>`);
+        if (right.length) {
+            output.push(...helpers.simpleGroup(right, this.elisionEnd));
+        }
+        else {
+            output.push('');
+        }
+        if (this.is4()) {
+            assert(this.address4 instanceof ipv4_1.Address4);
+            output.pop();
+            output.push(this.address4.groupForV6());
+        }
+        return output.join(':');
+    }
+    // #endregion
+    // #region Regular expressions
+    /**
+     * Generate a regular expression string that can be used to find or validate
+     * all variations of this address
+     * @memberof Address6
+     * @instance
+     * @param {boolean} substringSearch
+     * @returns {string}
+     */
+    regularExpressionString(substringSearch = false) {
+        let output = [];
+        // TODO: revisit why this is necessary
+        const address6 = new Address6(this.correctForm());
+        if (address6.elidedGroups === 0) {
+            // The simple case
+            output.push((0, regular_expressions_1.simpleRegularExpression)(address6.parsedAddress));
+        }
+        else if (address6.elidedGroups === constants6.GROUPS) {
+            // A completely elided address
+            output.push((0, regular_expressions_1.possibleElisions)(constants6.GROUPS));
+        }
+        else {
+            // A partially elided address
+            const halves = address6.address.split('::');
+            if (halves[0].length) {
+                output.push((0, regular_expressions_1.simpleRegularExpression)(halves[0].split(':')));
+            }
+            assert(typeof address6.elidedGroups === 'number');
+            output.push((0, regular_expressions_1.possibleElisions)(address6.elidedGroups, halves[0].length !== 0, halves[1].length !== 0));
+            if (halves[1].length) {
+                output.push((0, regular_expressions_1.simpleRegularExpression)(halves[1].split(':')));
+            }
+            output = [output.join(':')];
+        }
+        if (!substringSearch) {
+            output = [
+                '(?=^|',
+                regular_expressions_1.ADDRESS_BOUNDARY,
+                '|[^\\w\\:])(',
+                ...output,
+                ')(?=[^\\w\\:]|',
+                regular_expressions_1.ADDRESS_BOUNDARY,
+                '|$)',
+            ];
+        }
+        return output.join('');
+    }
+    /**
+     * Generate a regular expression that can be used to find or validate all
+     * variations of this address.
+     * @memberof Address6
+     * @instance
+     * @param {boolean} substringSearch
+     * @returns {RegExp}
+     */
+    regularExpression(substringSearch = false) {
+        return new RegExp(this.regularExpressionString(substringSearch), 'i');
+    }
+}
+exports.Address6 = Address6;
+//# sourceMappingURL=ipv6.js.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/ipv6.js.map b/server/node_modules/ip-address/dist/ipv6.js.map
new file mode 100644
index 0000000..05d59a0
--- /dev/null
+++ b/server/node_modules/ip-address/dist/ipv6.js.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v4/constants.d.ts b/server/node_modules/ip-address/dist/v4/constants.d.ts
new file mode 100644
index 0000000..4e85d4a
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v4/constants.d.ts
@@ -0,0 +1,5 @@
+export declare const BITS = 32;
+export declare const GROUPS = 4;
+export declare const RE_ADDRESS: RegExp;
+export declare const RE_SUBNET_STRING: RegExp;
+//# sourceMappingURL=constants.d.ts.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v4/constants.d.ts.map b/server/node_modules/ip-address/dist/v4/constants.d.ts.map
new file mode 100644
index 0000000..ea60ced
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v4/constants.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"constants.d.ts","sourceRoot":"","sources":["../../src/v4/constants.ts"],"names":[],"mappings":"AAAA,eAAO,MAAM,IAAI,KAAK,CAAC;AACvB,eAAO,MAAM,MAAM,IAAI,CAAC;AAExB,eAAO,MAAM,UAAU,QAC8I,CAAC;AAEtK,eAAO,MAAM,gBAAgB,QAAe,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v4/constants.js b/server/node_modules/ip-address/dist/v4/constants.js
new file mode 100644
index 0000000..6fa2518
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v4/constants.js
@@ -0,0 +1,8 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.RE_SUBNET_STRING = exports.RE_ADDRESS = exports.GROUPS = exports.BITS = void 0;
+exports.BITS = 32;
+exports.GROUPS = 4;
+exports.RE_ADDRESS = /^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/g;
+exports.RE_SUBNET_STRING = /\/\d{1,2}$/;
+//# sourceMappingURL=constants.js.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v4/constants.js.map b/server/node_modules/ip-address/dist/v4/constants.js.map
new file mode 100644
index 0000000..0a96f86
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v4/constants.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"constants.js","sourceRoot":"","sources":["../../src/v4/constants.ts"],"names":[],"mappings":";;;AAAa,QAAA,IAAI,GAAG,EAAE,CAAC;AACV,QAAA,MAAM,GAAG,CAAC,CAAC;AAEX,QAAA,UAAU,GACrB,mKAAmK,CAAC;AAEzJ,QAAA,gBAAgB,GAAG,YAAY,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/constants.d.ts b/server/node_modules/ip-address/dist/v6/constants.d.ts
new file mode 100644
index 0000000..1302375
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/constants.d.ts
@@ -0,0 +1,45 @@
+export declare const BITS = 128;
+export declare const GROUPS = 8;
+/**
+ * Represents IPv6 address scopes
+ * @memberof Address6
+ * @static
+ */
+export declare const SCOPES: {
+    [key: number]: string | undefined;
+};
+/**
+ * Represents IPv6 address types
+ * @memberof Address6
+ * @static
+ */
+export declare const TYPES: {
+    [key: string]: string | undefined;
+};
+/**
+ * A regular expression that matches bad characters in an IPv6 address
+ * @memberof Address6
+ * @static
+ */
+export declare const RE_BAD_CHARACTERS: RegExp;
+/**
+ * A regular expression that matches an incorrect IPv6 address
+ * @memberof Address6
+ * @static
+ */
+export declare const RE_BAD_ADDRESS: RegExp;
+/**
+ * A regular expression that matches an IPv6 subnet
+ * @memberof Address6
+ * @static
+ */
+export declare const RE_SUBNET_STRING: RegExp;
+/**
+ * A regular expression that matches an IPv6 zone
+ * @memberof Address6
+ * @static
+ */
+export declare const RE_ZONE_STRING: RegExp;
+export declare const RE_URL: RegExp;
+export declare const RE_URL_WITH_PORT: RegExp;
+//# sourceMappingURL=constants.d.ts.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/constants.d.ts.map b/server/node_modules/ip-address/dist/v6/constants.d.ts.map
new file mode 100644
index 0000000..0f4f412
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/constants.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"constants.d.ts","sourceRoot":"","sources":["../../src/v6/constants.ts"],"names":[],"mappings":"AAAA,eAAO,MAAM,IAAI,MAAM,CAAC;AACxB,eAAO,MAAM,MAAM,IAAI,CAAC;AAExB;;;;GAIG;AACH,eAAO,MAAM,MAAM,EAAE;IAAE,CAAC,GAAG,EAAE,MAAM,GAAG,MAAM,GAAG,SAAS,CAAA;CAS9C,CAAC;AAEX;;;;GAIG;AACH,eAAO,MAAM,KAAK,EAAE;IAAE,CAAC,GAAG,EAAE,MAAM,GAAG,MAAM,GAAG,SAAS,CAAA;CAuB7C,CAAC;AAEX;;;;GAIG;AACH,eAAO,MAAM,iBAAiB,QAAqB,CAAC;AAEpD;;;;GAIG;AACH,eAAO,MAAM,cAAc,QAA6C,CAAC;AAEzE;;;;GAIG;AACH,eAAO,MAAM,gBAAgB,QAAqB,CAAC;AAEnD;;;;GAIG;AACH,eAAO,MAAM,cAAc,QAAS,CAAC;AAErC,eAAO,MAAM,MAAM,QAAgC,CAAC;AACpD,eAAO,MAAM,gBAAgB,QAAkC,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/constants.js b/server/node_modules/ip-address/dist/v6/constants.js
new file mode 100644
index 0000000..0abc423
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/constants.js
@@ -0,0 +1,76 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.RE_URL_WITH_PORT = exports.RE_URL = exports.RE_ZONE_STRING = exports.RE_SUBNET_STRING = exports.RE_BAD_ADDRESS = exports.RE_BAD_CHARACTERS = exports.TYPES = exports.SCOPES = exports.GROUPS = exports.BITS = void 0;
+exports.BITS = 128;
+exports.GROUPS = 8;
+/**
+ * Represents IPv6 address scopes
+ * @memberof Address6
+ * @static
+ */
+exports.SCOPES = {
+    0: 'Reserved',
+    1: 'Interface local',
+    2: 'Link local',
+    4: 'Admin local',
+    5: 'Site local',
+    8: 'Organization local',
+    14: 'Global',
+    15: 'Reserved',
+};
+/**
+ * Represents IPv6 address types
+ * @memberof Address6
+ * @static
+ */
+exports.TYPES = {
+    'ff01::1/128': 'Multicast (All nodes on this interface)',
+    'ff01::2/128': 'Multicast (All routers on this interface)',
+    'ff02::1/128': 'Multicast (All nodes on this link)',
+    'ff02::2/128': 'Multicast (All routers on this link)',
+    'ff05::2/128': 'Multicast (All routers in this site)',
+    'ff02::5/128': 'Multicast (OSPFv3 AllSPF routers)',
+    'ff02::6/128': 'Multicast (OSPFv3 AllDR routers)',
+    'ff02::9/128': 'Multicast (RIP routers)',
+    'ff02::a/128': 'Multicast (EIGRP routers)',
+    'ff02::d/128': 'Multicast (PIM routers)',
+    'ff02::16/128': 'Multicast (MLDv2 reports)',
+    'ff01::fb/128': 'Multicast (mDNSv6)',
+    'ff02::fb/128': 'Multicast (mDNSv6)',
+    'ff05::fb/128': 'Multicast (mDNSv6)',
+    'ff02::1:2/128': 'Multicast (All DHCP servers and relay agents on this link)',
+    'ff05::1:2/128': 'Multicast (All DHCP servers and relay agents in this site)',
+    'ff02::1:3/128': 'Multicast (All DHCP servers on this link)',
+    'ff05::1:3/128': 'Multicast (All DHCP servers in this site)',
+    '::/128': 'Unspecified',
+    '::1/128': 'Loopback',
+    'ff00::/8': 'Multicast',
+    'fe80::/10': 'Link-local unicast',
+};
+/**
+ * A regular expression that matches bad characters in an IPv6 address
+ * @memberof Address6
+ * @static
+ */
+exports.RE_BAD_CHARACTERS = /([^0-9a-f:/%])/gi;
+/**
+ * A regular expression that matches an incorrect IPv6 address
+ * @memberof Address6
+ * @static
+ */
+exports.RE_BAD_ADDRESS = /([0-9a-f]{5,}|:{3,}|[^:]:$|^:[^:]|\/$)/gi;
+/**
+ * A regular expression that matches an IPv6 subnet
+ * @memberof Address6
+ * @static
+ */
+exports.RE_SUBNET_STRING = /\/\d{1,3}(?=%|$)/;
+/**
+ * A regular expression that matches an IPv6 zone
+ * @memberof Address6
+ * @static
+ */
+exports.RE_ZONE_STRING = /%.*$/;
+exports.RE_URL = /^\[{0,1}([0-9a-f:]+)\]{0,1}/;
+exports.RE_URL_WITH_PORT = /\[([0-9a-f:]+)\]:([0-9]{1,5})/;
+//# sourceMappingURL=constants.js.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/constants.js.map b/server/node_modules/ip-address/dist/v6/constants.js.map
new file mode 100644
index 0000000..1d313e0
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/constants.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"constants.js","sourceRoot":"","sources":["../../src/v6/constants.ts"],"names":[],"mappings":";;;AAAa,QAAA,IAAI,GAAG,GAAG,CAAC;AACX,QAAA,MAAM,GAAG,CAAC,CAAC;AAExB;;;;GAIG;AACU,QAAA,MAAM,GAA0C;IAC3D,CAAC,EAAE,UAAU;IACb,CAAC,EAAE,iBAAiB;IACpB,CAAC,EAAE,YAAY;IACf,CAAC,EAAE,aAAa;IAChB,CAAC,EAAE,YAAY;IACf,CAAC,EAAE,oBAAoB;IACvB,EAAE,EAAE,QAAQ;IACZ,EAAE,EAAE,UAAU;CACN,CAAC;AAEX;;;;GAIG;AACU,QAAA,KAAK,GAA0C;IAC1D,aAAa,EAAE,yCAAyC;IACxD,aAAa,EAAE,2CAA2C;IAC1D,aAAa,EAAE,oCAAoC;IACnD,aAAa,EAAE,sCAAsC;IACrD,aAAa,EAAE,sCAAsC;IACrD,aAAa,EAAE,mCAAmC;IAClD,aAAa,EAAE,kCAAkC;IACjD,aAAa,EAAE,yBAAyB;IACxC,aAAa,EAAE,2BAA2B;IAC1C,aAAa,EAAE,yBAAyB;IACxC,cAAc,EAAE,2BAA2B;IAC3C,cAAc,EAAE,oBAAoB;IACpC,cAAc,EAAE,oBAAoB;IACpC,cAAc,EAAE,oBAAoB;IACpC,eAAe,EAAE,4DAA4D;IAC7E,eAAe,EAAE,4DAA4D;IAC7E,eAAe,EAAE,2CAA2C;IAC5D,eAAe,EAAE,2CAA2C;IAC5D,QAAQ,EAAE,aAAa;IACvB,SAAS,EAAE,UAAU;IACrB,UAAU,EAAE,WAAW;IACvB,WAAW,EAAE,oBAAoB;CACzB,CAAC;AAEX;;;;GAIG;AACU,QAAA,iBAAiB,GAAG,kBAAkB,CAAC;AAEpD;;;;GAIG;AACU,QAAA,cAAc,GAAG,0CAA0C,CAAC;AAEzE;;;;GAIG;AACU,QAAA,gBAAgB,GAAG,kBAAkB,CAAC;AAEnD;;;;GAIG;AACU,QAAA,cAAc,GAAG,MAAM,CAAC;AAExB,QAAA,MAAM,GAAG,6BAA6B,CAAC;AACvC,QAAA,gBAAgB,GAAG,+BAA+B,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/helpers.d.ts b/server/node_modules/ip-address/dist/v6/helpers.d.ts
new file mode 100644
index 0000000..e72f031
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/helpers.d.ts
@@ -0,0 +1,18 @@
+/**
+ * @returns {String} the string with all zeroes contained in a <span>
+ */
+export declare function spanAllZeroes(s: string): string;
+/**
+ * @returns {String} the string with each character contained in a <span>
+ */
+export declare function spanAll(s: string, offset?: number): string;
+/**
+ * @returns {String} the string with leading zeroes contained in a <span>
+ */
+export declare function spanLeadingZeroes(address: string): string;
+/**
+ * Groups an address
+ * @returns {String} a grouped address
+ */
+export declare function simpleGroup(addressString: string, offset?: number): string[];
+//# sourceMappingURL=helpers.d.ts.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/helpers.d.ts.map b/server/node_modules/ip-address/dist/v6/helpers.d.ts.map
new file mode 100644
index 0000000..823f26e
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/helpers.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"helpers.d.ts","sourceRoot":"","sources":["../../src/v6/helpers.ts"],"names":[],"mappings":"AAAA;;GAEG;AACH,wBAAgB,aAAa,CAAC,CAAC,EAAE,MAAM,GAAG,MAAM,CAE/C;AAED;;GAEG;AACH,wBAAgB,OAAO,CAAC,CAAC,EAAE,MAAM,EAAE,MAAM,GAAE,MAAU,GAAG,MAAM,CAQ7D;AAMD;;GAEG;AACH,wBAAgB,iBAAiB,CAAC,OAAO,EAAE,MAAM,GAAG,MAAM,CAIzD;AAED;;;GAGG;AACH,wBAAgB,WAAW,CAAC,aAAa,EAAE,MAAM,EAAE,MAAM,GAAE,MAAU,GAAG,MAAM,EAAE,CAU/E"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/helpers.js b/server/node_modules/ip-address/dist/v6/helpers.js
new file mode 100644
index 0000000..fafca0c
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/helpers.js
@@ -0,0 +1,45 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.spanAllZeroes = spanAllZeroes;
+exports.spanAll = spanAll;
+exports.spanLeadingZeroes = spanLeadingZeroes;
+exports.simpleGroup = simpleGroup;
+/**
+ * @returns {String} the string with all zeroes contained in a <span>
+ */
+function spanAllZeroes(s) {
+    return s.replace(/(0+)/g, '<span class="zero">$1</span>');
+}
+/**
+ * @returns {String} the string with each character contained in a <span>
+ */
+function spanAll(s, offset = 0) {
+    const letters = s.split('');
+    return letters
+        .map((n, i) => `<span class="digit value-${n} position-${i + offset}">${spanAllZeroes(n)}</span>`)
+        .join('');
+}
+function spanLeadingZeroesSimple(group) {
+    return group.replace(/^(0+)/, '<span class="zero">$1</span>');
+}
+/**
+ * @returns {String} the string with leading zeroes contained in a <span>
+ */
+function spanLeadingZeroes(address) {
+    const groups = address.split(':');
+    return groups.map((g) => spanLeadingZeroesSimple(g)).join(':');
+}
+/**
+ * Groups an address
+ * @returns {String} a grouped address
+ */
+function simpleGroup(addressString, offset = 0) {
+    const groups = addressString.split(':');
+    return groups.map((g, i) => {
+        if (/group-v4/.test(g)) {
+            return g;
+        }
+        return `<span class="hover-group group-${i + offset}">${spanLeadingZeroesSimple(g)}</span>`;
+    });
+}
+//# sourceMappingURL=helpers.js.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/helpers.js.map b/server/node_modules/ip-address/dist/v6/helpers.js.map
new file mode 100644
index 0000000..c895455
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/helpers.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"helpers.js","sourceRoot":"","sources":["../../src/v6/helpers.ts"],"names":[],"mappings":";;AAGA,sCAEC;AAKD,0BAQC;AASD,8CAIC;AAMD,kCAUC;AA/CD;;GAEG;AACH,SAAgB,aAAa,CAAC,CAAS;IACrC,OAAO,CAAC,CAAC,OAAO,CAAC,OAAO,EAAE,8BAA8B,CAAC,CAAC;AAC5D,CAAC;AAED;;GAEG;AACH,SAAgB,OAAO,CAAC,CAAS,EAAE,SAAiB,CAAC;IACnD,MAAM,OAAO,GAAG,CAAC,CAAC,KAAK,CAAC,EAAE,CAAC,CAAC;IAE5B,OAAO,OAAO;SACX,GAAG,CACF,CAAC,CAAC,EAAE,CAAC,EAAE,EAAE,CAAC,4BAA4B,CAAC,aAAa,CAAC,GAAG,MAAM,KAAK,aAAa,CAAC,CAAC,CAAC,SAAS,CAC7F;SACA,IAAI,CAAC,EAAE,CAAC,CAAC;AACd,CAAC;AAED,SAAS,uBAAuB,CAAC,KAAa;IAC5C,OAAO,KAAK,CAAC,OAAO,CAAC,OAAO,EAAE,8BAA8B,CAAC,CAAC;AAChE,CAAC;AAED;;GAEG;AACH,SAAgB,iBAAiB,CAAC,OAAe;IAC/C,MAAM,MAAM,GAAG,OAAO,CAAC,KAAK,CAAC,GAAG,CAAC,CAAC;IAElC,OAAO,MAAM,CAAC,GAAG,CAAC,CAAC,CAAC,EAAE,EAAE,CAAC,uBAAuB,CAAC,CAAC,CAAC,CAAC,CAAC,IAAI,CAAC,GAAG,CAAC,CAAC;AACjE,CAAC;AAED;;;GAGG;AACH,SAAgB,WAAW,CAAC,aAAqB,EAAE,SAAiB,CAAC;IACnE,MAAM,MAAM,GAAG,aAAa,CAAC,KAAK,CAAC,GAAG,CAAC,CAAC;IAExC,OAAO,MAAM,CAAC,GAAG,CAAC,CAAC,CAAC,EAAE,CAAC,EAAE,EAAE;QACzB,IAAI,UAAU,CAAC,IAAI,CAAC,CAAC,CAAC,EAAE,CAAC;YACvB,OAAO,CAAC,CAAC;QACX,CAAC;QAED,OAAO,kCAAkC,CAAC,GAAG,MAAM,KAAK,uBAAuB,CAAC,CAAC,CAAC,SAAS,CAAC;IAC9F,CAAC,CAAC,CAAC;AACL,CAAC"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/regular-expressions.d.ts b/server/node_modules/ip-address/dist/v6/regular-expressions.d.ts
new file mode 100644
index 0000000..181b91e
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/regular-expressions.d.ts
@@ -0,0 +1,6 @@
+export declare function groupPossibilities(possibilities: string[]): string;
+export declare function padGroup(group: string): string;
+export declare const ADDRESS_BOUNDARY = "[^A-Fa-f0-9:]";
+export declare function simpleRegularExpression(groups: string[]): string;
+export declare function possibleElisions(elidedGroups: number, moreLeft?: boolean, moreRight?: boolean): string;
+//# sourceMappingURL=regular-expressions.d.ts.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/regular-expressions.d.ts.map b/server/node_modules/ip-address/dist/v6/regular-expressions.d.ts.map
new file mode 100644
index 0000000..20a93f7
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/regular-expressions.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"regular-expressions.d.ts","sourceRoot":"","sources":["../../src/v6/regular-expressions.ts"],"names":[],"mappings":"AAEA,wBAAgB,kBAAkB,CAAC,aAAa,EAAE,MAAM,EAAE,GAAG,MAAM,CAElE;AAED,wBAAgB,QAAQ,CAAC,KAAK,EAAE,MAAM,GAAG,MAAM,CAM9C;AAED,eAAO,MAAM,gBAAgB,kBAAkB,CAAC;AAEhD,wBAAgB,uBAAuB,CAAC,MAAM,EAAE,MAAM,EAAE,UA+BvD;AAED,wBAAgB,gBAAgB,CAC9B,YAAY,EAAE,MAAM,EACpB,QAAQ,CAAC,EAAE,OAAO,EAClB,SAAS,CAAC,EAAE,OAAO,GAClB,MAAM,CAwCR"}
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/regular-expressions.js b/server/node_modules/ip-address/dist/v6/regular-expressions.js
new file mode 100644
index 0000000..a2c5145
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/regular-expressions.js
@@ -0,0 +1,95 @@
+"use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.ADDRESS_BOUNDARY = void 0;
+exports.groupPossibilities = groupPossibilities;
+exports.padGroup = padGroup;
+exports.simpleRegularExpression = simpleRegularExpression;
+exports.possibleElisions = possibleElisions;
+const v6 = __importStar(require("./constants"));
+function groupPossibilities(possibilities) {
+    return `(${possibilities.join('|')})`;
+}
+function padGroup(group) {
+    if (group.length < 4) {
+        return `0{0,${4 - group.length}}${group}`;
+    }
+    return group;
+}
+exports.ADDRESS_BOUNDARY = '[^A-Fa-f0-9:]';
+function simpleRegularExpression(groups) {
+    const zeroIndexes = [];
+    groups.forEach((group, i) => {
+        const groupInteger = parseInt(group, 16);
+        if (groupInteger === 0) {
+            zeroIndexes.push(i);
+        }
+    });
+    // You can technically elide a single 0, this creates the regular expressions
+    // to match that eventuality
+    const possibilities = zeroIndexes.map((zeroIndex) => groups
+        .map((group, i) => {
+        if (i === zeroIndex) {
+            const elision = i === 0 || i === v6.GROUPS - 1 ? ':' : '';
+            return groupPossibilities([padGroup(group), elision]);
+        }
+        return padGroup(group);
+    })
+        .join(':'));
+    // The simplest case
+    possibilities.push(groups.map(padGroup).join(':'));
+    return groupPossibilities(possibilities);
+}
+function possibleElisions(elidedGroups, moreLeft, moreRight) {
+    const left = moreLeft ? '' : ':';
+    const right = moreRight ? '' : ':';
+    const possibilities = [];
+    // 1. elision of everything (::)
+    if (!moreLeft && !moreRight) {
+        possibilities.push('::');
+    }
+    // 2. complete elision of the middle
+    if (moreLeft && moreRight) {
+        possibilities.push('');
+    }
+    if ((moreRight && !moreLeft) || (!moreRight && moreLeft)) {
+        // 3. complete elision of one side
+        possibilities.push(':');
+    }
+    // 4. elision from the left side
+    possibilities.push(`${left}(:0{1,4}){1,${elidedGroups - 1}}`);
+    // 5. elision from the right side
+    possibilities.push(`(0{1,4}:){1,${elidedGroups - 1}}${right}`);
+    // 6. no elision
+    possibilities.push(`(0{1,4}:){${elidedGroups - 1}}0{1,4}`);
+    // 7. elision (including sloppy elision) from the middle
+    for (let groups = 1; groups < elidedGroups - 1; groups++) {
+        for (let position = 1; position < elidedGroups - groups; position++) {
+            possibilities.push(`(0{1,4}:){${position}}:(0{1,4}:){${elidedGroups - position - groups - 1}}0{1,4}`);
+        }
+    }
+    return groupPossibilities(possibilities);
+}
+//# sourceMappingURL=regular-expressions.js.map
\ No newline at end of file
diff --git a/server/node_modules/ip-address/dist/v6/regular-expressions.js.map b/server/node_modules/ip-address/dist/v6/regular-expressions.js.map
new file mode 100644
index 0000000..190fd4a
--- /dev/null
+++ b/server/node_modules/ip-address/dist/v6/regular-expressions.js.map
@@ -0,0 +1 @@
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diff --git a/server/node_modules/ip-address/package.json b/server/node_modules/ip-address/package.json
new file mode 100644
index 0000000..5cf811e
--- /dev/null
+++ b/server/node_modules/ip-address/package.json
@@ -0,0 +1,78 @@
+{
+  "name": "ip-address",
+  "description": "A library for parsing IPv4 and IPv6 IP addresses in node and the browser.",
+  "keywords": [
+    "ipv6",
+    "ipv4",
+    "browser",
+    "validation"
+  ],
+  "version": "10.1.0",
+  "author": "Beau Gunderson <beau@beaugunderson.com> (https://beaugunderson.com/)",
+  "license": "MIT",
+  "main": "dist/ip-address.js",
+  "types": "dist/ip-address.d.ts",
+  "scripts": {
+    "docs": "documentation build --github --output docs --format html ./ip-address.js",
+    "build": "rm -rf dist; mkdir dist; tsc",
+    "prepack": "npm run build",
+    "release": "release-it",
+    "test-ci": "nyc mocha",
+    "test": "mocha",
+    "watch": "mocha --watch"
+  },
+  "nyc": {
+    "extension": [
+      ".ts"
+    ],
+    "exclude": [
+      "**/*.d.ts",
+      ".eslintrc.js",
+      "coverage/",
+      "dist/",
+      "test/",
+      "tmp/"
+    ],
+    "reporter": [
+      "html",
+      "lcov",
+      "text"
+    ],
+    "all": true
+  },
+  "engines": {
+    "node": ">= 12"
+  },
+  "files": [
+    "src",
+    "dist"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/beaugunderson/ip-address.git"
+  },
+  "devDependencies": {
+    "@types/chai": "^5.0.0",
+    "@types/mocha": "^10.0.8",
+    "@typescript-eslint/eslint-plugin": "^8.8.0",
+    "@typescript-eslint/parser": "^8.8.0",
+    "chai": "^5.1.1",
+    "documentation": "^14.0.3",
+    "eslint": "^8.50.0",
+    "eslint_d": "^14.0.4",
+    "eslint-config-airbnb": "^19.0.4",
+    "eslint-config-prettier": "^9.1.0",
+    "eslint-plugin-filenames": "^1.3.2",
+    "eslint-plugin-import": "^2.30.0",
+    "eslint-plugin-jsx-a11y": "^6.10.0",
+    "eslint-plugin-prettier": "^5.2.1",
+    "eslint-plugin-sort-imports-es6-autofix": "^0.6.0",
+    "mocha": "^10.7.3",
+    "nyc": "^17.1.0",
+    "prettier": "^3.3.3",
+    "release-it": "^17.6.0",
+    "source-map-support": "^0.5.21",
+    "tsx": "^4.19.1",
+    "typescript": "<5.6.0"
+  }
+}
diff --git a/server/node_modules/ip-address/src/address-error.ts b/server/node_modules/ip-address/src/address-error.ts
new file mode 100644
index 0000000..032d4cd
--- /dev/null
+++ b/server/node_modules/ip-address/src/address-error.ts
@@ -0,0 +1,11 @@
+export class AddressError extends Error {
+  parseMessage?: string;
+
+  constructor(message: string, parseMessage?: string) {
+    super(message);
+
+    this.name = 'AddressError';
+
+    this.parseMessage = parseMessage;
+  }
+}
diff --git a/server/node_modules/ip-address/src/common.ts b/server/node_modules/ip-address/src/common.ts
new file mode 100644
index 0000000..1123fa3
--- /dev/null
+++ b/server/node_modules/ip-address/src/common.ts
@@ -0,0 +1,55 @@
+import { Address4 } from './ipv4';
+import { Address6 } from './ipv6';
+
+export interface ReverseFormOptions {
+  omitSuffix?: boolean;
+}
+
+export function isInSubnet(this: Address4 | Address6, address: Address4 | Address6) {
+  if (this.subnetMask < address.subnetMask) {
+    return false;
+  }
+
+  if (this.mask(address.subnetMask) === address.mask()) {
+    return true;
+  }
+
+  return false;
+}
+
+export function isCorrect(defaultBits: number) {
+  return function (this: Address4 | Address6) {
+    if (this.addressMinusSuffix !== this.correctForm()) {
+      return false;
+    }
+
+    if (this.subnetMask === defaultBits && !this.parsedSubnet) {
+      return true;
+    }
+
+    return this.parsedSubnet === String(this.subnetMask);
+  };
+}
+
+export function numberToPaddedHex(number: number) {
+  return number.toString(16).padStart(2, '0');
+}
+
+export function stringToPaddedHex(numberString: string) {
+  return numberToPaddedHex(parseInt(numberString, 10));
+}
+
+/**
+ * @param binaryValue Binary representation of a value (e.g. `10`)
+ * @param position Byte position, where 0 is the least significant bit
+ */
+export function testBit(binaryValue: string, position: number): boolean {
+  const { length } = binaryValue;
+
+  if (position > length) {
+    return false;
+  }
+
+  const positionInString = length - position;
+  return binaryValue.substring(positionInString, positionInString + 1) === '1';
+}
diff --git a/server/node_modules/ip-address/src/ip-address.ts b/server/node_modules/ip-address/src/ip-address.ts
new file mode 100644
index 0000000..b4e1502
--- /dev/null
+++ b/server/node_modules/ip-address/src/ip-address.ts
@@ -0,0 +1,7 @@
+export { Address4 } from './ipv4';
+export { Address6 } from './ipv6';
+export { AddressError } from './address-error';
+
+import * as helpers from './v6/helpers';
+
+export const v6 = { helpers };
diff --git a/server/node_modules/ip-address/src/ipv4.ts b/server/node_modules/ip-address/src/ipv4.ts
new file mode 100644
index 0000000..7c7ce30
--- /dev/null
+++ b/server/node_modules/ip-address/src/ipv4.ts
@@ -0,0 +1,394 @@
+/* eslint-disable no-param-reassign */
+
+import * as common from './common';
+import * as constants from './v4/constants';
+import { AddressError } from './address-error';
+
+/**
+ * Represents an IPv4 address
+ * @class Address4
+ * @param {string} address - An IPv4 address string
+ */
+export class Address4 {
+  address: string;
+  addressMinusSuffix?: string;
+  groups: number = constants.GROUPS;
+  parsedAddress: string[] = [];
+  parsedSubnet: string = '';
+  subnet: string = '/32';
+  subnetMask: number = 32;
+  v4: boolean = true;
+
+  constructor(address: string) {
+    this.address = address;
+
+    const subnet = constants.RE_SUBNET_STRING.exec(address);
+
+    if (subnet) {
+      this.parsedSubnet = subnet[0].replace('/', '');
+      this.subnetMask = parseInt(this.parsedSubnet, 10);
+      this.subnet = `/${this.subnetMask}`;
+
+      if (this.subnetMask < 0 || this.subnetMask > constants.BITS) {
+        throw new AddressError('Invalid subnet mask.');
+      }
+
+      address = address.replace(constants.RE_SUBNET_STRING, '');
+    }
+
+    this.addressMinusSuffix = address;
+
+    this.parsedAddress = this.parse(address);
+  }
+
+  static isValid(address: string): boolean {
+    try {
+      // eslint-disable-next-line no-new
+      new Address4(address);
+
+      return true;
+    } catch (e) {
+      return false;
+    }
+  }
+
+  /*
+   * Parses a v4 address
+   */
+  parse(address: string) {
+    const groups = address.split('.');
+
+    if (!address.match(constants.RE_ADDRESS)) {
+      throw new AddressError('Invalid IPv4 address.');
+    }
+
+    return groups;
+  }
+
+  /**
+   * Returns the correct form of an address
+   * @memberof Address4
+   * @instance
+   * @returns {String}
+   */
+  correctForm(): string {
+    return this.parsedAddress.map((part) => parseInt(part, 10)).join('.');
+  }
+
+  /**
+   * Returns true if the address is correct, false otherwise
+   * @memberof Address4
+   * @instance
+   * @returns {Boolean}
+   */
+  isCorrect = common.isCorrect(constants.BITS);
+
+  /**
+   * Converts a hex string to an IPv4 address object
+   * @memberof Address4
+   * @static
+   * @param {string} hex - a hex string to convert
+   * @returns {Address4}
+   */
+  static fromHex(hex: string): Address4 {
+    const padded = hex.replace(/:/g, '').padStart(8, '0');
+    const groups = [];
+    let i;
+
+    for (i = 0; i < 8; i += 2) {
+      const h = padded.slice(i, i + 2);
+
+      groups.push(parseInt(h, 16));
+    }
+
+    return new Address4(groups.join('.'));
+  }
+
+  /**
+   * Converts an integer into a IPv4 address object
+   * @memberof Address4
+   * @static
+   * @param {integer} integer - a number to convert
+   * @returns {Address4}
+   */
+  static fromInteger(integer: number): Address4 {
+    return Address4.fromHex(integer.toString(16));
+  }
+
+  /**
+   * Return an address from in-addr.arpa form
+   * @memberof Address4
+   * @static
+   * @param {string} arpaFormAddress - an 'in-addr.arpa' form ipv4 address
+   * @returns {Adress4}
+   * @example
+   * var address = Address4.fromArpa(42.2.0.192.in-addr.arpa.)
+   * address.correctForm(); // '192.0.2.42'
+   */
+  static fromArpa(arpaFormAddress: string): Address4 {
+    // remove ending ".in-addr.arpa." or just "."
+    const leader = arpaFormAddress.replace(/(\.in-addr\.arpa)?\.$/, '');
+
+    const address = leader.split('.').reverse().join('.');
+
+    return new Address4(address);
+  }
+
+  /**
+   * Converts an IPv4 address object to a hex string
+   * @memberof Address4
+   * @instance
+   * @returns {String}
+   */
+  toHex(): string {
+    return this.parsedAddress.map((part) => common.stringToPaddedHex(part)).join(':');
+  }
+
+  /**
+   * Converts an IPv4 address object to an array of bytes
+   * @memberof Address4
+   * @instance
+   * @returns {Array}
+   */
+  toArray(): number[] {
+    return this.parsedAddress.map((part) => parseInt(part, 10));
+  }
+
+  /**
+   * Converts an IPv4 address object to an IPv6 address group
+   * @memberof Address4
+   * @instance
+   * @returns {String}
+   */
+  toGroup6(): string {
+    const output = [];
+    let i;
+
+    for (i = 0; i < constants.GROUPS; i += 2) {
+      output.push(
+        `${common.stringToPaddedHex(this.parsedAddress[i])}${common.stringToPaddedHex(
+          this.parsedAddress[i + 1],
+        )}`,
+      );
+    }
+
+    return output.join(':');
+  }
+
+  /**
+   * Returns the address as a `bigint`
+   * @memberof Address4
+   * @instance
+   * @returns {bigint}
+   */
+  bigInt(): bigint {
+    return BigInt(`0x${this.parsedAddress.map((n) => common.stringToPaddedHex(n)).join('')}`);
+  }
+
+  /**
+   * Helper function getting start address.
+   * @memberof Address4
+   * @instance
+   * @returns {bigint}
+   */
+  _startAddress(): bigint {
+    return BigInt(`0b${this.mask() + '0'.repeat(constants.BITS - this.subnetMask)}`);
+  }
+
+  /**
+   * The first address in the range given by this address' subnet.
+   * Often referred to as the Network Address.
+   * @memberof Address4
+   * @instance
+   * @returns {Address4}
+   */
+  startAddress(): Address4 {
+    return Address4.fromBigInt(this._startAddress());
+  }
+
+  /**
+   * The first host address in the range given by this address's subnet ie
+   * the first address after the Network Address
+   * @memberof Address4
+   * @instance
+   * @returns {Address4}
+   */
+  startAddressExclusive(): Address4 {
+    const adjust = BigInt('1');
+    return Address4.fromBigInt(this._startAddress() + adjust);
+  }
+
+  /**
+   * Helper function getting end address.
+   * @memberof Address4
+   * @instance
+   * @returns {bigint}
+   */
+  _endAddress(): bigint {
+    return BigInt(`0b${this.mask() + '1'.repeat(constants.BITS - this.subnetMask)}`);
+  }
+
+  /**
+   * The last address in the range given by this address' subnet
+   * Often referred to as the Broadcast
+   * @memberof Address4
+   * @instance
+   * @returns {Address4}
+   */
+  endAddress(): Address4 {
+    return Address4.fromBigInt(this._endAddress());
+  }
+
+  /**
+   * The last host address in the range given by this address's subnet ie
+   * the last address prior to the Broadcast Address
+   * @memberof Address4
+   * @instance
+   * @returns {Address4}
+   */
+  endAddressExclusive(): Address4 {
+    const adjust = BigInt('1');
+    return Address4.fromBigInt(this._endAddress() - adjust);
+  }
+
+  /**
+   * Converts a BigInt to a v4 address object
+   * @memberof Address4
+   * @static
+   * @param {bigint} bigInt - a BigInt to convert
+   * @returns {Address4}
+   */
+  static fromBigInt(bigInt: bigint): Address4 {
+    return Address4.fromHex(bigInt.toString(16));
+  }
+
+  /**
+   * Convert a byte array to an Address4 object
+   * @memberof Address4
+   * @static
+   * @param {Array<number>} bytes - an array of 4 bytes (0-255)
+   * @returns {Address4}
+   */
+  static fromByteArray(bytes: Array<number>): Address4 {
+    if (bytes.length !== 4) {
+      throw new AddressError('IPv4 addresses require exactly 4 bytes');
+    }
+
+    // Validate that all bytes are within valid range (0-255)
+    for (let i = 0; i < bytes.length; i++) {
+      if (!Number.isInteger(bytes[i]) || bytes[i] < 0 || bytes[i] > 255) {
+        throw new AddressError('All bytes must be integers between 0 and 255');
+      }
+    }
+
+    return this.fromUnsignedByteArray(bytes);
+  }
+
+  /**
+   * Convert an unsigned byte array to an Address4 object
+   * @memberof Address4
+   * @static
+   * @param {Array<number>} bytes - an array of 4 unsigned bytes (0-255)
+   * @returns {Address4}
+   */
+  static fromUnsignedByteArray(bytes: Array<number>): Address4 {
+    if (bytes.length !== 4) {
+      throw new AddressError('IPv4 addresses require exactly 4 bytes');
+    }
+
+    const address = bytes.join('.');
+    return new Address4(address);
+  }
+
+  /**
+   * Returns the first n bits of the address, defaulting to the
+   * subnet mask
+   * @memberof Address4
+   * @instance
+   * @returns {String}
+   */
+  mask(mask?: number): string {
+    if (mask === undefined) {
+      mask = this.subnetMask;
+    }
+
+    return this.getBitsBase2(0, mask);
+  }
+
+  /**
+   * Returns the bits in the given range as a base-2 string
+   * @memberof Address4
+   * @instance
+   * @returns {string}
+   */
+  getBitsBase2(start: number, end: number): string {
+    return this.binaryZeroPad().slice(start, end);
+  }
+
+  /**
+   * Return the reversed ip6.arpa form of the address
+   * @memberof Address4
+   * @param {Object} options
+   * @param {boolean} options.omitSuffix - omit the "in-addr.arpa" suffix
+   * @instance
+   * @returns {String}
+   */
+  reverseForm(options?: common.ReverseFormOptions): string {
+    if (!options) {
+      options = {};
+    }
+
+    const reversed = this.correctForm().split('.').reverse().join('.');
+
+    if (options.omitSuffix) {
+      return reversed;
+    }
+
+    return `${reversed}.in-addr.arpa.`;
+  }
+
+  /**
+   * Returns true if the given address is in the subnet of the current address
+   * @memberof Address4
+   * @instance
+   * @returns {boolean}
+   */
+  isInSubnet = common.isInSubnet;
+
+  /**
+   * Returns true if the given address is a multicast address
+   * @memberof Address4
+   * @instance
+   * @returns {boolean}
+   */
+  isMulticast(): boolean {
+    return this.isInSubnet(new Address4('224.0.0.0/4'));
+  }
+
+  /**
+   * Returns a zero-padded base-2 string representation of the address
+   * @memberof Address4
+   * @instance
+   * @returns {string}
+   */
+  binaryZeroPad(): string {
+    return this.bigInt().toString(2).padStart(constants.BITS, '0');
+  }
+
+  /**
+   * Groups an IPv4 address for inclusion at the end of an IPv6 address
+   * @returns {String}
+   */
+  groupForV6(): string {
+    const segments = this.parsedAddress;
+
+    return this.address.replace(
+      constants.RE_ADDRESS,
+      `<span class="hover-group group-v4 group-6">${segments
+        .slice(0, 2)
+        .join('.')}</span>.<span class="hover-group group-v4 group-7">${segments
+        .slice(2, 4)
+        .join('.')}</span>`,
+    );
+  }
+}
diff --git a/server/node_modules/ip-address/src/ipv6.ts b/server/node_modules/ip-address/src/ipv6.ts
new file mode 100644
index 0000000..60348e9
--- /dev/null
+++ b/server/node_modules/ip-address/src/ipv6.ts
@@ -0,0 +1,1212 @@
+/* eslint-disable prefer-destructuring */
+/* eslint-disable no-param-reassign */
+
+import * as common from './common';
+import * as constants4 from './v4/constants';
+import * as constants6 from './v6/constants';
+import * as helpers from './v6/helpers';
+import { Address4 } from './ipv4';
+import {
+  ADDRESS_BOUNDARY,
+  possibleElisions,
+  simpleRegularExpression,
+} from './v6/regular-expressions';
+import { AddressError } from './address-error';
+import { testBit } from './common';
+
+function assert(condition: any): asserts condition {
+  if (!condition) {
+    throw new Error('Assertion failed.');
+  }
+}
+
+function addCommas(number: string): string {
+  const r = /(\d+)(\d{3})/;
+
+  while (r.test(number)) {
+    number = number.replace(r, '$1,$2');
+  }
+
+  return number;
+}
+
+function spanLeadingZeroes4(n: string): string {
+  n = n.replace(/^(0{1,})([1-9]+)$/, '<span class="parse-error">$1</span>$2');
+  n = n.replace(/^(0{1,})(0)$/, '<span class="parse-error">$1</span>$2');
+
+  return n;
+}
+
+/*
+ * A helper function to compact an array
+ */
+function compact(address: string[], slice: number[]) {
+  const s1 = [];
+  const s2 = [];
+  let i;
+
+  for (i = 0; i < address.length; i++) {
+    if (i < slice[0]) {
+      s1.push(address[i]);
+    } else if (i > slice[1]) {
+      s2.push(address[i]);
+    }
+  }
+
+  return s1.concat(['compact']).concat(s2);
+}
+
+function paddedHex(octet: string): string {
+  return parseInt(octet, 16).toString(16).padStart(4, '0');
+}
+
+function unsignByte(b: number) {
+  // eslint-disable-next-line no-bitwise
+  return b & 0xff;
+}
+
+interface SixToFourProperties {
+  prefix: string;
+  gateway: string;
+}
+
+interface TeredoProperties {
+  prefix: string;
+  server4: string;
+  client4: string;
+  flags: string;
+  coneNat: boolean;
+  microsoft: {
+    reserved: boolean;
+    universalLocal: boolean;
+    groupIndividual: boolean;
+    nonce: string;
+  };
+  udpPort: string;
+}
+
+/**
+ * Represents an IPv6 address
+ * @class Address6
+ * @param {string} address - An IPv6 address string
+ * @param {number} [groups=8] - How many octets to parse
+ * @example
+ * var address = new Address6('2001::/32');
+ */
+export class Address6 {
+  address4?: Address4;
+  address: string;
+  addressMinusSuffix: string = '';
+  elidedGroups?: number;
+  elisionBegin?: number;
+  elisionEnd?: number;
+  groups: number;
+  parsedAddress4?: string;
+  parsedAddress: string[];
+  parsedSubnet: string = '';
+  subnet: string = '/128';
+  subnetMask: number = 128;
+  v4: boolean = false;
+  zone: string = '';
+
+  constructor(address: string, optionalGroups?: number) {
+    if (optionalGroups === undefined) {
+      this.groups = constants6.GROUPS;
+    } else {
+      this.groups = optionalGroups;
+    }
+
+    this.address = address;
+
+    const subnet = constants6.RE_SUBNET_STRING.exec(address);
+
+    if (subnet) {
+      this.parsedSubnet = subnet[0].replace('/', '');
+      this.subnetMask = parseInt(this.parsedSubnet, 10);
+      this.subnet = `/${this.subnetMask}`;
+
+      if (
+        Number.isNaN(this.subnetMask) ||
+        this.subnetMask < 0 ||
+        this.subnetMask > constants6.BITS
+      ) {
+        throw new AddressError('Invalid subnet mask.');
+      }
+
+      address = address.replace(constants6.RE_SUBNET_STRING, '');
+    } else if (/\//.test(address)) {
+      throw new AddressError('Invalid subnet mask.');
+    }
+
+    const zone = constants6.RE_ZONE_STRING.exec(address);
+
+    if (zone) {
+      this.zone = zone[0];
+
+      address = address.replace(constants6.RE_ZONE_STRING, '');
+    }
+
+    this.addressMinusSuffix = address;
+
+    this.parsedAddress = this.parse(this.addressMinusSuffix);
+  }
+
+  static isValid(address: string): boolean {
+    try {
+      // eslint-disable-next-line no-new
+      new Address6(address);
+
+      return true;
+    } catch (e) {
+      return false;
+    }
+  }
+
+  /**
+   * Convert a BigInt to a v6 address object
+   * @memberof Address6
+   * @static
+   * @param {bigint} bigInt - a BigInt to convert
+   * @returns {Address6}
+   * @example
+   * var bigInt = BigInt('1000000000000');
+   * var address = Address6.fromBigInt(bigInt);
+   * address.correctForm(); // '::e8:d4a5:1000'
+   */
+  static fromBigInt(bigInt: bigint): Address6 {
+    const hex = bigInt.toString(16).padStart(32, '0');
+    const groups = [];
+    let i;
+
+    for (i = 0; i < constants6.GROUPS; i++) {
+      groups.push(hex.slice(i * 4, (i + 1) * 4));
+    }
+
+    return new Address6(groups.join(':'));
+  }
+
+  /**
+   * Convert a URL (with optional port number) to an address object
+   * @memberof Address6
+   * @static
+   * @param {string} url - a URL with optional port number
+   * @example
+   * var addressAndPort = Address6.fromURL('http://[ffff::]:8080/foo/');
+   * addressAndPort.address.correctForm(); // 'ffff::'
+   * addressAndPort.port; // 8080
+   */
+  static fromURL(url: string) {
+    let host: string;
+    let port: string | number | null = null;
+    let result: string[] | null;
+
+    // If we have brackets parse them and find a port
+    if (url.indexOf('[') !== -1 && url.indexOf(']:') !== -1) {
+      result = constants6.RE_URL_WITH_PORT.exec(url);
+
+      if (result === null) {
+        return {
+          error: 'failed to parse address with port',
+          address: null,
+          port: null,
+        };
+      }
+
+      host = result[1];
+      port = result[2];
+      // If there's a URL extract the address
+    } else if (url.indexOf('/') !== -1) {
+      // Remove the protocol prefix
+      url = url.replace(/^[a-z0-9]+:\/\//, '');
+
+      // Parse the address
+      result = constants6.RE_URL.exec(url);
+
+      if (result === null) {
+        return {
+          error: 'failed to parse address from URL',
+          address: null,
+          port: null,
+        };
+      }
+
+      host = result[1];
+      // Otherwise just assign the URL to the host and let the library parse it
+    } else {
+      host = url;
+    }
+
+    // If there's a port convert it to an integer
+    if (port) {
+      port = parseInt(port, 10);
+
+      // squelch out of range ports
+      if (port < 0 || port > 65536) {
+        port = null;
+      }
+    } else {
+      // Standardize `undefined` to `null`
+      port = null;
+    }
+
+    return {
+      address: new Address6(host),
+      port,
+    };
+  }
+
+  /**
+   * Create an IPv6-mapped address given an IPv4 address
+   * @memberof Address6
+   * @static
+   * @param {string} address - An IPv4 address string
+   * @returns {Address6}
+   * @example
+   * var address = Address6.fromAddress4('192.168.0.1');
+   * address.correctForm(); // '::ffff:c0a8:1'
+   * address.to4in6(); // '::ffff:192.168.0.1'
+   */
+  static fromAddress4(address: string): Address6 {
+    const address4 = new Address4(address);
+
+    const mask6 = constants6.BITS - (constants4.BITS - address4.subnetMask);
+
+    return new Address6(`::ffff:${address4.correctForm()}/${mask6}`);
+  }
+
+  /**
+   * Return an address from ip6.arpa form
+   * @memberof Address6
+   * @static
+   * @param {string} arpaFormAddress - an 'ip6.arpa' form address
+   * @returns {Adress6}
+   * @example
+   * var address = Address6.fromArpa(e.f.f.f.3.c.2.6.f.f.f.e.6.6.8.e.1.0.6.7.9.4.e.c.0.0.0.0.1.0.0.2.ip6.arpa.)
+   * address.correctForm(); // '2001:0:ce49:7601:e866:efff:62c3:fffe'
+   */
+  static fromArpa(arpaFormAddress: string): Address6 {
+    // remove ending ".ip6.arpa." or just "."
+    let address = arpaFormAddress.replace(/(\.ip6\.arpa)?\.$/, '');
+    const semicolonAmount = 7;
+
+    // correct ip6.arpa form with ending removed will be 63 characters
+    if (address.length !== 63) {
+      throw new AddressError("Invalid 'ip6.arpa' form.");
+    }
+
+    const parts = address.split('.').reverse();
+
+    for (let i = semicolonAmount; i > 0; i--) {
+      const insertIndex = i * 4;
+      parts.splice(insertIndex, 0, ':');
+    }
+
+    address = parts.join('');
+
+    return new Address6(address);
+  }
+
+  /**
+   * Return the Microsoft UNC transcription of the address
+   * @memberof Address6
+   * @instance
+   * @returns {String} the Microsoft UNC transcription of the address
+   */
+  microsoftTranscription(): string {
+    return `${this.correctForm().replace(/:/g, '-')}.ipv6-literal.net`;
+  }
+
+  /**
+   * Return the first n bits of the address, defaulting to the subnet mask
+   * @memberof Address6
+   * @instance
+   * @param {number} [mask=subnet] - the number of bits to mask
+   * @returns {String} the first n bits of the address as a string
+   */
+  mask(mask: number = this.subnetMask): string {
+    return this.getBitsBase2(0, mask);
+  }
+
+  /**
+   * Return the number of possible subnets of a given size in the address
+   * @memberof Address6
+   * @instance
+   * @param {number} [subnetSize=128] - the subnet size
+   * @returns {String}
+   */
+  // TODO: probably useful to have a numeric version of this too
+  possibleSubnets(subnetSize: number = 128): string {
+    const availableBits = constants6.BITS - this.subnetMask;
+    const subnetBits = Math.abs(subnetSize - constants6.BITS);
+    const subnetPowers = availableBits - subnetBits;
+
+    if (subnetPowers < 0) {
+      return '0';
+    }
+
+    return addCommas((BigInt('2') ** BigInt(subnetPowers)).toString(10));
+  }
+
+  /**
+   * Helper function getting start address.
+   * @memberof Address6
+   * @instance
+   * @returns {bigint}
+   */
+  _startAddress(): bigint {
+    return BigInt(`0b${this.mask() + '0'.repeat(constants6.BITS - this.subnetMask)}`);
+  }
+
+  /**
+   * The first address in the range given by this address' subnet
+   * Often referred to as the Network Address.
+   * @memberof Address6
+   * @instance
+   * @returns {Address6}
+   */
+  startAddress(): Address6 {
+    return Address6.fromBigInt(this._startAddress());
+  }
+
+  /**
+   * The first host address in the range given by this address's subnet ie
+   * the first address after the Network Address
+   * @memberof Address6
+   * @instance
+   * @returns {Address6}
+   */
+  startAddressExclusive(): Address6 {
+    const adjust = BigInt('1');
+    return Address6.fromBigInt(this._startAddress() + adjust);
+  }
+
+  /**
+   * Helper function getting end address.
+   * @memberof Address6
+   * @instance
+   * @returns {bigint}
+   */
+  _endAddress(): bigint {
+    return BigInt(`0b${this.mask() + '1'.repeat(constants6.BITS - this.subnetMask)}`);
+  }
+
+  /**
+   * The last address in the range given by this address' subnet
+   * Often referred to as the Broadcast
+   * @memberof Address6
+   * @instance
+   * @returns {Address6}
+   */
+  endAddress(): Address6 {
+    return Address6.fromBigInt(this._endAddress());
+  }
+
+  /**
+   * The last host address in the range given by this address's subnet ie
+   * the last address prior to the Broadcast Address
+   * @memberof Address6
+   * @instance
+   * @returns {Address6}
+   */
+  endAddressExclusive(): Address6 {
+    const adjust = BigInt('1');
+    return Address6.fromBigInt(this._endAddress() - adjust);
+  }
+
+  /**
+   * Return the scope of the address
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   */
+  getScope(): string {
+    let scope = constants6.SCOPES[parseInt(this.getBits(12, 16).toString(10), 10)];
+
+    if (this.getType() === 'Global unicast' && scope !== 'Link local') {
+      scope = 'Global';
+    }
+
+    return scope || 'Unknown';
+  }
+
+  /**
+   * Return the type of the address
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   */
+  getType(): string {
+    for (const subnet of Object.keys(constants6.TYPES)) {
+      if (this.isInSubnet(new Address6(subnet))) {
+        return constants6.TYPES[subnet] as string;
+      }
+    }
+
+    return 'Global unicast';
+  }
+
+  /**
+   * Return the bits in the given range as a BigInt
+   * @memberof Address6
+   * @instance
+   * @returns {bigint}
+   */
+  getBits(start: number, end: number): bigint {
+    return BigInt(`0b${this.getBitsBase2(start, end)}`);
+  }
+
+  /**
+   * Return the bits in the given range as a base-2 string
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   */
+  getBitsBase2(start: number, end: number): string {
+    return this.binaryZeroPad().slice(start, end);
+  }
+
+  /**
+   * Return the bits in the given range as a base-16 string
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   */
+  getBitsBase16(start: number, end: number): string {
+    const length = end - start;
+
+    if (length % 4 !== 0) {
+      throw new Error('Length of bits to retrieve must be divisible by four');
+    }
+
+    return this.getBits(start, end)
+      .toString(16)
+      .padStart(length / 4, '0');
+  }
+
+  /**
+   * Return the bits that are set past the subnet mask length
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   */
+  getBitsPastSubnet(): string {
+    return this.getBitsBase2(this.subnetMask, constants6.BITS);
+  }
+
+  /**
+   * Return the reversed ip6.arpa form of the address
+   * @memberof Address6
+   * @param {Object} options
+   * @param {boolean} options.omitSuffix - omit the "ip6.arpa" suffix
+   * @instance
+   * @returns {String}
+   */
+  reverseForm(options?: common.ReverseFormOptions): string {
+    if (!options) {
+      options = {};
+    }
+
+    const characters = Math.floor(this.subnetMask / 4);
+
+    const reversed = this.canonicalForm()
+      .replace(/:/g, '')
+      .split('')
+      .slice(0, characters)
+      .reverse()
+      .join('.');
+
+    if (characters > 0) {
+      if (options.omitSuffix) {
+        return reversed;
+      }
+
+      return `${reversed}.ip6.arpa.`;
+    }
+
+    if (options.omitSuffix) {
+      return '';
+    }
+
+    return 'ip6.arpa.';
+  }
+
+  /**
+   * Return the correct form of the address
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   */
+  correctForm(): string {
+    let i;
+    let groups = [];
+
+    let zeroCounter = 0;
+    const zeroes = [];
+
+    for (i = 0; i < this.parsedAddress.length; i++) {
+      const value = parseInt(this.parsedAddress[i], 16);
+
+      if (value === 0) {
+        zeroCounter++;
+      }
+
+      if (value !== 0 && zeroCounter > 0) {
+        if (zeroCounter > 1) {
+          zeroes.push([i - zeroCounter, i - 1]);
+        }
+
+        zeroCounter = 0;
+      }
+    }
+
+    // Do we end with a string of zeroes?
+    if (zeroCounter > 1) {
+      zeroes.push([this.parsedAddress.length - zeroCounter, this.parsedAddress.length - 1]);
+    }
+
+    const zeroLengths = zeroes.map((n) => n[1] - n[0] + 1);
+
+    if (zeroes.length > 0) {
+      const index = zeroLengths.indexOf(Math.max(...zeroLengths) as number);
+
+      groups = compact(this.parsedAddress, zeroes[index]);
+    } else {
+      groups = this.parsedAddress;
+    }
+
+    for (i = 0; i < groups.length; i++) {
+      if (groups[i] !== 'compact') {
+        groups[i] = parseInt(groups[i], 16).toString(16);
+      }
+    }
+
+    let correct = groups.join(':');
+
+    correct = correct.replace(/^compact$/, '::');
+    correct = correct.replace(/(^compact)|(compact$)/, ':');
+    correct = correct.replace(/compact/, '');
+
+    return correct;
+  }
+
+  /**
+   * Return a zero-padded base-2 string representation of the address
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   * @example
+   * var address = new Address6('2001:4860:4001:803::1011');
+   * address.binaryZeroPad();
+   * // '0010000000000001010010000110000001000000000000010000100000000011
+   * //  0000000000000000000000000000000000000000000000000001000000010001'
+   */
+  binaryZeroPad(): string {
+    return this.bigInt().toString(2).padStart(constants6.BITS, '0');
+  }
+
+  // TODO: Improve the semantics of this helper function
+  parse4in6(address: string): string {
+    const groups = address.split(':');
+    const lastGroup = groups.slice(-1)[0];
+
+    const address4 = lastGroup.match(constants4.RE_ADDRESS);
+
+    if (address4) {
+      this.parsedAddress4 = address4[0];
+      this.address4 = new Address4(this.parsedAddress4);
+
+      for (let i = 0; i < this.address4.groups; i++) {
+        if (/^0[0-9]+/.test(this.address4.parsedAddress[i])) {
+          throw new AddressError(
+            "IPv4 addresses can't have leading zeroes.",
+            address.replace(
+              constants4.RE_ADDRESS,
+              this.address4.parsedAddress.map(spanLeadingZeroes4).join('.'),
+            ),
+          );
+        }
+      }
+
+      this.v4 = true;
+
+      groups[groups.length - 1] = this.address4.toGroup6();
+
+      address = groups.join(':');
+    }
+
+    return address;
+  }
+
+  // TODO: Make private?
+  parse(address: string): string[] {
+    address = this.parse4in6(address);
+
+    const badCharacters = address.match(constants6.RE_BAD_CHARACTERS);
+
+    if (badCharacters) {
+      throw new AddressError(
+        `Bad character${
+          badCharacters.length > 1 ? 's' : ''
+        } detected in address: ${badCharacters.join('')}`,
+        address.replace(constants6.RE_BAD_CHARACTERS, '<span class="parse-error">$1</span>'),
+      );
+    }
+
+    const badAddress = address.match(constants6.RE_BAD_ADDRESS);
+
+    if (badAddress) {
+      throw new AddressError(
+        `Address failed regex: ${badAddress.join('')}`,
+        address.replace(constants6.RE_BAD_ADDRESS, '<span class="parse-error">$1</span>'),
+      );
+    }
+
+    let groups: string[] = [];
+
+    const halves = address.split('::');
+
+    if (halves.length === 2) {
+      let first = halves[0].split(':');
+      let last = halves[1].split(':');
+
+      if (first.length === 1 && first[0] === '') {
+        first = [];
+      }
+
+      if (last.length === 1 && last[0] === '') {
+        last = [];
+      }
+
+      const remaining = this.groups - (first.length + last.length);
+
+      if (!remaining) {
+        throw new AddressError('Error parsing groups');
+      }
+
+      this.elidedGroups = remaining;
+
+      this.elisionBegin = first.length;
+      this.elisionEnd = first.length + this.elidedGroups;
+
+      groups = groups.concat(first);
+
+      for (let i = 0; i < remaining; i++) {
+        groups.push('0');
+      }
+
+      groups = groups.concat(last);
+    } else if (halves.length === 1) {
+      groups = address.split(':');
+
+      this.elidedGroups = 0;
+    } else {
+      throw new AddressError('Too many :: groups found');
+    }
+
+    groups = groups.map((group: string) => parseInt(group, 16).toString(16));
+
+    if (groups.length !== this.groups) {
+      throw new AddressError('Incorrect number of groups found');
+    }
+
+    return groups;
+  }
+
+  /**
+   * Return the canonical form of the address
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   */
+  canonicalForm(): string {
+    return this.parsedAddress.map(paddedHex).join(':');
+  }
+
+  /**
+   * Return the decimal form of the address
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   */
+  decimal(): string {
+    return this.parsedAddress.map((n) => parseInt(n, 16).toString(10).padStart(5, '0')).join(':');
+  }
+
+  /**
+   * Return the address as a BigInt
+   * @memberof Address6
+   * @instance
+   * @returns {bigint}
+   */
+  bigInt(): bigint {
+    return BigInt(`0x${this.parsedAddress.map(paddedHex).join('')}`);
+  }
+
+  /**
+   * Return the last two groups of this address as an IPv4 address string
+   * @memberof Address6
+   * @instance
+   * @returns {Address4}
+   * @example
+   * var address = new Address6('2001:4860:4001::1825:bf11');
+   * address.to4().correctForm(); // '24.37.191.17'
+   */
+  to4(): Address4 {
+    const binary = this.binaryZeroPad().split('');
+
+    return Address4.fromHex(BigInt(`0b${binary.slice(96, 128).join('')}`).toString(16));
+  }
+
+  /**
+   * Return the v4-in-v6 form of the address
+   * @memberof Address6
+   * @instance
+   * @returns {String}
+   */
+  to4in6(): string {
+    const address4 = this.to4();
+    const address6 = new Address6(this.parsedAddress.slice(0, 6).join(':'), 6);
+
+    const correct = address6.correctForm();
+
+    let infix = '';
+
+    if (!/:$/.test(correct)) {
+      infix = ':';
+    }
+
+    return correct + infix + address4.address;
+  }
+
+  /**
+   * Return an object containing the Teredo properties of the address
+   * @memberof Address6
+   * @instance
+   * @returns {Object}
+   */
+  inspectTeredo(): TeredoProperties {
+    /*
+    - Bits 0 to 31 are set to the Teredo prefix (normally 2001:0000::/32).
+    - Bits 32 to 63 embed the primary IPv4 address of the Teredo server that
+      is used.
+    - Bits 64 to 79 can be used to define some flags. Currently only the
+      higher order bit is used; it is set to 1 if the Teredo client is
+      located behind a cone NAT, 0 otherwise. For Microsoft's Windows Vista
+      and Windows Server 2008 implementations, more bits are used. In those
+      implementations, the format for these 16 bits is "CRAAAAUG AAAAAAAA",
+      where "C" remains the "Cone" flag. The "R" bit is reserved for future
+      use. The "U" bit is for the Universal/Local flag (set to 0). The "G" bit
+      is Individual/Group flag (set to 0). The A bits are set to a 12-bit
+      randomly generated number chosen by the Teredo client to introduce
+      additional protection for the Teredo node against IPv6-based scanning
+      attacks.
+    - Bits 80 to 95 contains the obfuscated UDP port number. This is the
+      port number that is mapped by the NAT to the Teredo client with all
+      bits inverted.
+    - Bits 96 to 127 contains the obfuscated IPv4 address. This is the
+      public IPv4 address of the NAT with all bits inverted.
+    */
+    const prefix = this.getBitsBase16(0, 32);
+
+    const bitsForUdpPort: bigint = this.getBits(80, 96);
+    // eslint-disable-next-line no-bitwise
+    const udpPort = (bitsForUdpPort ^ BigInt('0xffff')).toString();
+
+    const server4 = Address4.fromHex(this.getBitsBase16(32, 64));
+
+    const bitsForClient4 = this.getBits(96, 128);
+    // eslint-disable-next-line no-bitwise
+    const client4 = Address4.fromHex((bitsForClient4 ^ BigInt('0xffffffff')).toString(16));
+
+    const flagsBase2 = this.getBitsBase2(64, 80);
+
+    const coneNat = testBit(flagsBase2, 15);
+    const reserved = testBit(flagsBase2, 14);
+    const groupIndividual = testBit(flagsBase2, 8);
+    const universalLocal = testBit(flagsBase2, 9);
+    const nonce = BigInt(`0b${flagsBase2.slice(2, 6) + flagsBase2.slice(8, 16)}`).toString(10);
+
+    return {
+      prefix: `${prefix.slice(0, 4)}:${prefix.slice(4, 8)}`,
+      server4: server4.address,
+      client4: client4.address,
+      flags: flagsBase2,
+      coneNat,
+      microsoft: {
+        reserved,
+        universalLocal,
+        groupIndividual,
+        nonce,
+      },
+      udpPort,
+    };
+  }
+
+  /**
+   * Return an object containing the 6to4 properties of the address
+   * @memberof Address6
+   * @instance
+   * @returns {Object}
+   */
+  inspect6to4(): SixToFourProperties {
+    /*
+    - Bits 0 to 15 are set to the 6to4 prefix (2002::/16).
+    - Bits 16 to 48 embed the IPv4 address of the 6to4 gateway that is used.
+    */
+
+    const prefix = this.getBitsBase16(0, 16);
+
+    const gateway = Address4.fromHex(this.getBitsBase16(16, 48));
+
+    return {
+      prefix: prefix.slice(0, 4),
+      gateway: gateway.address,
+    };
+  }
+
+  /**
+   * Return a v6 6to4 address from a v6 v4inv6 address
+   * @memberof Address6
+   * @instance
+   * @returns {Address6}
+   */
+  to6to4(): Address6 | null {
+    if (!this.is4()) {
+      return null;
+    }
+
+    const addr6to4 = [
+      '2002',
+      this.getBitsBase16(96, 112),
+      this.getBitsBase16(112, 128),
+      '',
+      '/16',
+    ].join(':');
+
+    return new Address6(addr6to4);
+  }
+
+  /**
+   * Return a byte array
+   * @memberof Address6
+   * @instance
+   * @returns {Array}
+   */
+  toByteArray(): number[] {
+    const valueWithoutPadding = this.bigInt().toString(16);
+    const leadingPad = '0'.repeat(valueWithoutPadding.length % 2);
+
+    const value = `${leadingPad}${valueWithoutPadding}`;
+
+    const bytes = [];
+    for (let i = 0, length = value.length; i < length; i += 2) {
+      bytes.push(parseInt(value.substring(i, i + 2), 16));
+    }
+
+    return bytes;
+  }
+
+  /**
+   * Return an unsigned byte array
+   * @memberof Address6
+   * @instance
+   * @returns {Array}
+   */
+  toUnsignedByteArray(): number[] {
+    return this.toByteArray().map(unsignByte);
+  }
+
+  /**
+   * Convert a byte array to an Address6 object
+   * @memberof Address6
+   * @static
+   * @returns {Address6}
+   */
+  static fromByteArray(bytes: Array<any>): Address6 {
+    return this.fromUnsignedByteArray(bytes.map(unsignByte));
+  }
+
+  /**
+   * Convert an unsigned byte array to an Address6 object
+   * @memberof Address6
+   * @static
+   * @returns {Address6}
+   */
+  static fromUnsignedByteArray(bytes: Array<any>): Address6 {
+    const BYTE_MAX = BigInt('256');
+    let result = BigInt('0');
+    let multiplier = BigInt('1');
+
+    for (let i = bytes.length - 1; i >= 0; i--) {
+      result += multiplier * BigInt(bytes[i].toString(10));
+
+      multiplier *= BYTE_MAX;
+    }
+
+    return Address6.fromBigInt(result);
+  }
+
+  // #region Attributes
+  /**
+   * Returns true if the given address is in the subnet of the current address
+   * @memberof Address6
+   * @instance
+   * @returns {boolean}
+   */
+  isInSubnet = common.isInSubnet;
+
+  /**
+   * Returns true if the address is correct, false otherwise
+   * @memberof Address6
+   * @instance
+   * @returns {boolean}
+   */
+  isCorrect = common.isCorrect(constants6.BITS);
+
+  /**
+   * Returns true if the address is in the canonical form, false otherwise
+   * @memberof Address6
+   * @instance
+   * @returns {boolean}
+   */
+  isCanonical(): boolean {
+    return this.addressMinusSuffix === this.canonicalForm();
+  }
+
+  /**
+   * Returns true if the address is a link local address, false otherwise
+   * @memberof Address6
+   * @instance
+   * @returns {boolean}
+   */
+  isLinkLocal(): boolean {
+    // Zeroes are required, i.e. we can't check isInSubnet with 'fe80::/10'
+    if (
+      this.getBitsBase2(0, 64) ===
+      '1111111010000000000000000000000000000000000000000000000000000000'
+    ) {
+      return true;
+    }
+
+    return false;
+  }
+
+  /**
+   * Returns true if the address is a multicast address, false otherwise
+   * @memberof Address6
+   * @instance
+   * @returns {boolean}
+   */
+  isMulticast(): boolean {
+    return this.getType() === 'Multicast';
+  }
+
+  /**
+   * Returns true if the address is a v4-in-v6 address, false otherwise
+   * @memberof Address6
+   * @instance
+   * @returns {boolean}
+   */
+  is4(): boolean {
+    return this.v4;
+  }
+
+  /**
+   * Returns true if the address is a Teredo address, false otherwise
+   * @memberof Address6
+   * @instance
+   * @returns {boolean}
+   */
+  isTeredo(): boolean {
+    return this.isInSubnet(new Address6('2001::/32'));
+  }
+
+  /**
+   * Returns true if the address is a 6to4 address, false otherwise
+   * @memberof Address6
+   * @instance
+   * @returns {boolean}
+   */
+  is6to4(): boolean {
+    return this.isInSubnet(new Address6('2002::/16'));
+  }
+
+  /**
+   * Returns true if the address is a loopback address, false otherwise
+   * @memberof Address6
+   * @instance
+   * @returns {boolean}
+   */
+  isLoopback(): boolean {
+    return this.getType() === 'Loopback';
+  }
+  // #endregion
+
+  // #region HTML
+  /**
+   * @returns {String} the address in link form with a default port of 80
+   */
+  href(optionalPort?: number | string): string {
+    if (optionalPort === undefined) {
+      optionalPort = '';
+    } else {
+      optionalPort = `:${optionalPort}`;
+    }
+
+    return `http://[${this.correctForm()}]${optionalPort}/`;
+  }
+
+  /**
+   * @returns {String} a link suitable for conveying the address via a URL hash
+   */
+  link(options?: { className?: string; prefix?: string; v4?: boolean }): string {
+    if (!options) {
+      options = {};
+    }
+
+    if (options.className === undefined) {
+      options.className = '';
+    }
+
+    if (options.prefix === undefined) {
+      options.prefix = '/#address=';
+    }
+
+    if (options.v4 === undefined) {
+      options.v4 = false;
+    }
+
+    let formFunction = this.correctForm;
+
+    if (options.v4) {
+      formFunction = this.to4in6;
+    }
+
+    const form = formFunction.call(this);
+
+    if (options.className) {
+      return `<a href="${options.prefix}${form}" class="${options.className}">${form}</a>`;
+    }
+
+    return `<a href="${options.prefix}${form}">${form}</a>`;
+  }
+
+  /**
+   * Groups an address
+   * @returns {String}
+   */
+  group(): string {
+    if (this.elidedGroups === 0) {
+      // The simple case
+      return helpers.simpleGroup(this.address).join(':');
+    }
+
+    assert(typeof this.elidedGroups === 'number');
+    assert(typeof this.elisionBegin === 'number');
+
+    // The elided case
+    const output = [];
+
+    const [left, right] = this.address.split('::');
+
+    if (left.length) {
+      output.push(...helpers.simpleGroup(left));
+    } else {
+      output.push('');
+    }
+
+    const classes = ['hover-group'];
+
+    for (let i = this.elisionBegin; i < this.elisionBegin + this.elidedGroups; i++) {
+      classes.push(`group-${i}`);
+    }
+
+    output.push(`<span class="${classes.join(' ')}"></span>`);
+
+    if (right.length) {
+      output.push(...helpers.simpleGroup(right, this.elisionEnd));
+    } else {
+      output.push('');
+    }
+
+    if (this.is4()) {
+      assert(this.address4 instanceof Address4);
+
+      output.pop();
+      output.push(this.address4.groupForV6());
+    }
+
+    return output.join(':');
+  }
+  // #endregion
+
+  // #region Regular expressions
+  /**
+   * Generate a regular expression string that can be used to find or validate
+   * all variations of this address
+   * @memberof Address6
+   * @instance
+   * @param {boolean} substringSearch
+   * @returns {string}
+   */
+  regularExpressionString(this: Address6, substringSearch: boolean = false): string {
+    let output: string[] = [];
+
+    // TODO: revisit why this is necessary
+    const address6 = new Address6(this.correctForm());
+
+    if (address6.elidedGroups === 0) {
+      // The simple case
+      output.push(simpleRegularExpression(address6.parsedAddress));
+    } else if (address6.elidedGroups === constants6.GROUPS) {
+      // A completely elided address
+      output.push(possibleElisions(constants6.GROUPS));
+    } else {
+      // A partially elided address
+      const halves = address6.address.split('::');
+
+      if (halves[0].length) {
+        output.push(simpleRegularExpression(halves[0].split(':')));
+      }
+
+      assert(typeof address6.elidedGroups === 'number');
+
+      output.push(
+        possibleElisions(address6.elidedGroups, halves[0].length !== 0, halves[1].length !== 0),
+      );
+
+      if (halves[1].length) {
+        output.push(simpleRegularExpression(halves[1].split(':')));
+      }
+
+      output = [output.join(':')];
+    }
+
+    if (!substringSearch) {
+      output = [
+        '(?=^|',
+        ADDRESS_BOUNDARY,
+        '|[^\\w\\:])(',
+        ...output,
+        ')(?=[^\\w\\:]|',
+        ADDRESS_BOUNDARY,
+        '|$)',
+      ];
+    }
+
+    return output.join('');
+  }
+
+  /**
+   * Generate a regular expression that can be used to find or validate all
+   * variations of this address.
+   * @memberof Address6
+   * @instance
+   * @param {boolean} substringSearch
+   * @returns {RegExp}
+   */
+  regularExpression(this: Address6, substringSearch: boolean = false): RegExp {
+    return new RegExp(this.regularExpressionString(substringSearch), 'i');
+  }
+  // #endregion
+}
diff --git a/server/node_modules/ip-address/src/v4/constants.ts b/server/node_modules/ip-address/src/v4/constants.ts
new file mode 100644
index 0000000..73c32f1
--- /dev/null
+++ b/server/node_modules/ip-address/src/v4/constants.ts
@@ -0,0 +1,7 @@
+export const BITS = 32;
+export const GROUPS = 4;
+
+export const RE_ADDRESS =
+  /^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/g;
+
+export const RE_SUBNET_STRING = /\/\d{1,2}$/;
diff --git a/server/node_modules/ip-address/src/v6/constants.ts b/server/node_modules/ip-address/src/v6/constants.ts
new file mode 100644
index 0000000..e23bfa5
--- /dev/null
+++ b/server/node_modules/ip-address/src/v6/constants.ts
@@ -0,0 +1,79 @@
+export const BITS = 128;
+export const GROUPS = 8;
+
+/**
+ * Represents IPv6 address scopes
+ * @memberof Address6
+ * @static
+ */
+export const SCOPES: { [key: number]: string | undefined } = {
+  0: 'Reserved',
+  1: 'Interface local',
+  2: 'Link local',
+  4: 'Admin local',
+  5: 'Site local',
+  8: 'Organization local',
+  14: 'Global',
+  15: 'Reserved',
+} as const;
+
+/**
+ * Represents IPv6 address types
+ * @memberof Address6
+ * @static
+ */
+export const TYPES: { [key: string]: string | undefined } = {
+  'ff01::1/128': 'Multicast (All nodes on this interface)',
+  'ff01::2/128': 'Multicast (All routers on this interface)',
+  'ff02::1/128': 'Multicast (All nodes on this link)',
+  'ff02::2/128': 'Multicast (All routers on this link)',
+  'ff05::2/128': 'Multicast (All routers in this site)',
+  'ff02::5/128': 'Multicast (OSPFv3 AllSPF routers)',
+  'ff02::6/128': 'Multicast (OSPFv3 AllDR routers)',
+  'ff02::9/128': 'Multicast (RIP routers)',
+  'ff02::a/128': 'Multicast (EIGRP routers)',
+  'ff02::d/128': 'Multicast (PIM routers)',
+  'ff02::16/128': 'Multicast (MLDv2 reports)',
+  'ff01::fb/128': 'Multicast (mDNSv6)',
+  'ff02::fb/128': 'Multicast (mDNSv6)',
+  'ff05::fb/128': 'Multicast (mDNSv6)',
+  'ff02::1:2/128': 'Multicast (All DHCP servers and relay agents on this link)',
+  'ff05::1:2/128': 'Multicast (All DHCP servers and relay agents in this site)',
+  'ff02::1:3/128': 'Multicast (All DHCP servers on this link)',
+  'ff05::1:3/128': 'Multicast (All DHCP servers in this site)',
+  '::/128': 'Unspecified',
+  '::1/128': 'Loopback',
+  'ff00::/8': 'Multicast',
+  'fe80::/10': 'Link-local unicast',
+} as const;
+
+/**
+ * A regular expression that matches bad characters in an IPv6 address
+ * @memberof Address6
+ * @static
+ */
+export const RE_BAD_CHARACTERS = /([^0-9a-f:/%])/gi;
+
+/**
+ * A regular expression that matches an incorrect IPv6 address
+ * @memberof Address6
+ * @static
+ */
+export const RE_BAD_ADDRESS = /([0-9a-f]{5,}|:{3,}|[^:]:$|^:[^:]|\/$)/gi;
+
+/**
+ * A regular expression that matches an IPv6 subnet
+ * @memberof Address6
+ * @static
+ */
+export const RE_SUBNET_STRING = /\/\d{1,3}(?=%|$)/;
+
+/**
+ * A regular expression that matches an IPv6 zone
+ * @memberof Address6
+ * @static
+ */
+export const RE_ZONE_STRING = /%.*$/;
+
+export const RE_URL = /^\[{0,1}([0-9a-f:]+)\]{0,1}/;
+export const RE_URL_WITH_PORT = /\[([0-9a-f:]+)\]:([0-9]{1,5})/;
diff --git a/server/node_modules/ip-address/src/v6/helpers.ts b/server/node_modules/ip-address/src/v6/helpers.ts
new file mode 100644
index 0000000..e40074c
--- /dev/null
+++ b/server/node_modules/ip-address/src/v6/helpers.ts
@@ -0,0 +1,48 @@
+/**
+ * @returns {String} the string with all zeroes contained in a <span>
+ */
+export function spanAllZeroes(s: string): string {
+  return s.replace(/(0+)/g, '<span class="zero">$1</span>');
+}
+
+/**
+ * @returns {String} the string with each character contained in a <span>
+ */
+export function spanAll(s: string, offset: number = 0): string {
+  const letters = s.split('');
+
+  return letters
+    .map(
+      (n, i) => `<span class="digit value-${n} position-${i + offset}">${spanAllZeroes(n)}</span>`,
+    )
+    .join('');
+}
+
+function spanLeadingZeroesSimple(group: string): string {
+  return group.replace(/^(0+)/, '<span class="zero">$1</span>');
+}
+
+/**
+ * @returns {String} the string with leading zeroes contained in a <span>
+ */
+export function spanLeadingZeroes(address: string): string {
+  const groups = address.split(':');
+
+  return groups.map((g) => spanLeadingZeroesSimple(g)).join(':');
+}
+
+/**
+ * Groups an address
+ * @returns {String} a grouped address
+ */
+export function simpleGroup(addressString: string, offset: number = 0): string[] {
+  const groups = addressString.split(':');
+
+  return groups.map((g, i) => {
+    if (/group-v4/.test(g)) {
+      return g;
+    }
+
+    return `<span class="hover-group group-${i + offset}">${spanLeadingZeroesSimple(g)}</span>`;
+  });
+}
diff --git a/server/node_modules/ip-address/src/v6/regular-expressions.ts b/server/node_modules/ip-address/src/v6/regular-expressions.ts
new file mode 100644
index 0000000..a511b84
--- /dev/null
+++ b/server/node_modules/ip-address/src/v6/regular-expressions.ts
@@ -0,0 +1,94 @@
+import * as v6 from './constants';
+
+export function groupPossibilities(possibilities: string[]): string {
+  return `(${possibilities.join('|')})`;
+}
+
+export function padGroup(group: string): string {
+  if (group.length < 4) {
+    return `0{0,${4 - group.length}}${group}`;
+  }
+
+  return group;
+}
+
+export const ADDRESS_BOUNDARY = '[^A-Fa-f0-9:]';
+
+export function simpleRegularExpression(groups: string[]) {
+  const zeroIndexes: number[] = [];
+
+  groups.forEach((group, i) => {
+    const groupInteger = parseInt(group, 16);
+
+    if (groupInteger === 0) {
+      zeroIndexes.push(i);
+    }
+  });
+
+  // You can technically elide a single 0, this creates the regular expressions
+  // to match that eventuality
+  const possibilities = zeroIndexes.map((zeroIndex) =>
+    groups
+      .map((group, i) => {
+        if (i === zeroIndex) {
+          const elision = i === 0 || i === v6.GROUPS - 1 ? ':' : '';
+
+          return groupPossibilities([padGroup(group), elision]);
+        }
+
+        return padGroup(group);
+      })
+      .join(':'),
+  );
+
+  // The simplest case
+  possibilities.push(groups.map(padGroup).join(':'));
+
+  return groupPossibilities(possibilities);
+}
+
+export function possibleElisions(
+  elidedGroups: number,
+  moreLeft?: boolean,
+  moreRight?: boolean,
+): string {
+  const left = moreLeft ? '' : ':';
+  const right = moreRight ? '' : ':';
+
+  const possibilities = [];
+
+  // 1. elision of everything (::)
+  if (!moreLeft && !moreRight) {
+    possibilities.push('::');
+  }
+
+  // 2. complete elision of the middle
+  if (moreLeft && moreRight) {
+    possibilities.push('');
+  }
+
+  if ((moreRight && !moreLeft) || (!moreRight && moreLeft)) {
+    // 3. complete elision of one side
+    possibilities.push(':');
+  }
+
+  // 4. elision from the left side
+  possibilities.push(`${left}(:0{1,4}){1,${elidedGroups - 1}}`);
+
+  // 5. elision from the right side
+  possibilities.push(`(0{1,4}:){1,${elidedGroups - 1}}${right}`);
+
+  // 6. no elision
+  possibilities.push(`(0{1,4}:){${elidedGroups - 1}}0{1,4}`);
+
+  // 7. elision (including sloppy elision) from the middle
+  for (let groups = 1; groups < elidedGroups - 1; groups++) {
+    for (let position = 1; position < elidedGroups - groups; position++) {
+      possibilities.push(
+        `(0{1,4}:){${position}}:(0{1,4}:){${elidedGroups - position - groups - 1}}0{1,4}`,
+      );
+    }
+  }
+
+  return groupPossibilities(possibilities);
+}
diff --git a/server/node_modules/ipaddr.js/LICENSE b/server/node_modules/ipaddr.js/LICENSE
new file mode 100644
index 0000000..f6b37b5
--- /dev/null
+++ b/server/node_modules/ipaddr.js/LICENSE
@@ -0,0 +1,19 @@
+Copyright (C) 2011-2017 whitequark <whitequark@whitequark.org>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/ipaddr.js/README.md b/server/node_modules/ipaddr.js/README.md
new file mode 100644
index 0000000..f57725b
--- /dev/null
+++ b/server/node_modules/ipaddr.js/README.md
@@ -0,0 +1,233 @@
+# ipaddr.js — an IPv6 and IPv4 address manipulation library [![Build Status](https://travis-ci.org/whitequark/ipaddr.js.svg)](https://travis-ci.org/whitequark/ipaddr.js)
+
+ipaddr.js is a small (1.9K minified and gzipped) library for manipulating
+IP addresses in JavaScript environments. It runs on both CommonJS runtimes
+(e.g. [nodejs]) and in a web browser.
+
+ipaddr.js allows you to verify and parse string representation of an IP
+address, match it against a CIDR range or range list, determine if it falls
+into some reserved ranges (examples include loopback and private ranges),
+and convert between IPv4 and IPv4-mapped IPv6 addresses.
+
+[nodejs]: http://nodejs.org
+
+## Installation
+
+`npm install ipaddr.js`
+
+or
+
+`bower install ipaddr.js`
+
+## API
+
+ipaddr.js defines one object in the global scope: `ipaddr`. In CommonJS,
+it is exported from the module:
+
+```js
+var ipaddr = require('ipaddr.js');
+```
+
+The API consists of several global methods and two classes: ipaddr.IPv6 and ipaddr.IPv4.
+
+### Global methods
+
+There are three global methods defined: `ipaddr.isValid`, `ipaddr.parse` and
+`ipaddr.process`. All of them receive a string as a single parameter.
+
+The `ipaddr.isValid` method returns `true` if the address is a valid IPv4 or
+IPv6 address, and `false` otherwise. It does not throw any exceptions.
+
+The `ipaddr.parse` method returns an object representing the IP address,
+or throws an `Error` if the passed string is not a valid representation of an
+IP address.
+
+The `ipaddr.process` method works just like the `ipaddr.parse` one, but it
+automatically converts IPv4-mapped IPv6 addresses to their IPv4 counterparts
+before returning. It is useful when you have a Node.js instance listening
+on an IPv6 socket, and the `net.ivp6.bindv6only` sysctl parameter (or its
+equivalent on non-Linux OS) is set to 0. In this case, you can accept IPv4
+connections on your IPv6-only socket, but the remote address will be mangled.
+Use `ipaddr.process` method to automatically demangle it.
+
+### Object representation
+
+Parsing methods return an object which descends from `ipaddr.IPv6` or
+`ipaddr.IPv4`. These objects share some properties, but most of them differ.
+
+#### Shared properties
+
+One can determine the type of address by calling `addr.kind()`. It will return
+either `"ipv6"` or `"ipv4"`.
+
+An address can be converted back to its string representation with `addr.toString()`.
+Note that this method:
+ * does not return the original string used to create the object (in fact, there is
+   no way of getting that string)
+ * returns a compact representation (when it is applicable)
+
+A `match(range, bits)` method can be used to check if the address falls into a
+certain CIDR range.
+Note that an address can be (obviously) matched only against an address of the same type.
+
+For example:
+
+```js
+var addr = ipaddr.parse("2001:db8:1234::1");
+var range = ipaddr.parse("2001:db8::");
+
+addr.match(range, 32); // => true
+```
+
+Alternatively, `match` can also be called as `match([range, bits])`. In this way,
+it can be used together with the `parseCIDR(string)` method, which parses an IP
+address together with a CIDR range.
+
+For example:
+
+```js
+var addr = ipaddr.parse("2001:db8:1234::1");
+
+addr.match(ipaddr.parseCIDR("2001:db8::/32")); // => true
+```
+
+A `range()` method returns one of predefined names for several special ranges defined
+by IP protocols. The exact names (and their respective CIDR ranges) can be looked up
+in the source: [IPv6 ranges] and [IPv4 ranges]. Some common ones include `"unicast"`
+(the default one) and `"reserved"`.
+
+You can match against your own range list by using
+`ipaddr.subnetMatch(address, rangeList, defaultName)` method. It can work with a mix of IPv6 or IPv4 addresses, and accepts a name-to-subnet map as the range list. For example:
+
+```js
+var rangeList = {
+  documentationOnly: [ ipaddr.parse('2001:db8::'), 32 ],
+  tunnelProviders: [
+    [ ipaddr.parse('2001:470::'), 32 ], // he.net
+    [ ipaddr.parse('2001:5c0::'), 32 ]  // freenet6
+  ]
+};
+ipaddr.subnetMatch(ipaddr.parse('2001:470:8:66::1'), rangeList, 'unknown'); // => "tunnelProviders"
+```
+
+The addresses can be converted to their byte representation with `toByteArray()`.
+(Actually, JavaScript mostly does not know about byte buffers. They are emulated with
+arrays of numbers, each in range of 0..255.)
+
+```js
+var bytes = ipaddr.parse('2a00:1450:8007::68').toByteArray(); // ipv6.google.com
+bytes // => [42, 0x00, 0x14, 0x50, 0x80, 0x07, 0x00, <zeroes...>, 0x00, 0x68 ]
+```
+
+The `ipaddr.IPv4` and `ipaddr.IPv6` objects have some methods defined, too. All of them
+have the same interface for both protocols, and are similar to global methods.
+
+`ipaddr.IPvX.isValid(string)` can be used to check if the string is a valid address
+for particular protocol, and `ipaddr.IPvX.parse(string)` is the error-throwing parser.
+
+`ipaddr.IPvX.isValid(string)` uses the same format for parsing as the POSIX `inet_ntoa` function, which accepts unusual formats like `0xc0.168.1.1` or `0x10000000`. The function `ipaddr.IPv4.isValidFourPartDecimal(string)` validates the IPv4 address and also ensures that it is written in four-part decimal format.
+
+[IPv6 ranges]: https://github.com/whitequark/ipaddr.js/blob/master/src/ipaddr.coffee#L186
+[IPv4 ranges]: https://github.com/whitequark/ipaddr.js/blob/master/src/ipaddr.coffee#L71
+
+#### IPv6 properties
+
+Sometimes you will want to convert IPv6 not to a compact string representation (with
+the `::` substitution); the `toNormalizedString()` method will return an address where
+all zeroes are explicit.
+
+For example:
+
+```js
+var addr = ipaddr.parse("2001:0db8::0001");
+addr.toString(); // => "2001:db8::1"
+addr.toNormalizedString(); // => "2001:db8:0:0:0:0:0:1"
+```
+
+The `isIPv4MappedAddress()` method will return `true` if this address is an IPv4-mapped
+one, and `toIPv4Address()` will return an IPv4 object address.
+
+To access the underlying binary representation of the address, use `addr.parts`.
+
+```js
+var addr = ipaddr.parse("2001:db8:10::1234:DEAD");
+addr.parts // => [0x2001, 0xdb8, 0x10, 0, 0, 0, 0x1234, 0xdead]
+```
+
+A IPv6 zone index can be accessed via `addr.zoneId`:
+
+```js
+var addr = ipaddr.parse("2001:db8::%eth0");
+addr.zoneId // => 'eth0'
+```
+
+#### IPv4 properties
+
+`toIPv4MappedAddress()` will return a corresponding IPv4-mapped IPv6 address.
+
+To access the underlying representation of the address, use `addr.octets`.
+
+```js
+var addr = ipaddr.parse("192.168.1.1");
+addr.octets // => [192, 168, 1, 1]
+```
+
+`prefixLengthFromSubnetMask()` will return a CIDR prefix length for a valid IPv4 netmask or
+null if the netmask is not valid.
+
+```js
+ipaddr.IPv4.parse('255.255.255.240').prefixLengthFromSubnetMask() == 28
+ipaddr.IPv4.parse('255.192.164.0').prefixLengthFromSubnetMask()  == null
+```
+
+`subnetMaskFromPrefixLength()` will return an IPv4 netmask for a valid CIDR prefix length.
+
+```js
+ipaddr.IPv4.subnetMaskFromPrefixLength(24) == "255.255.255.0"
+ipaddr.IPv4.subnetMaskFromPrefixLength(29) == "255.255.255.248"
+```
+
+`broadcastAddressFromCIDR()` will return the broadcast address for a given IPv4 interface and netmask in CIDR notation.
+```js
+ipaddr.IPv4.broadcastAddressFromCIDR("172.0.0.1/24") == "172.0.0.255"
+```
+`networkAddressFromCIDR()` will return the network address for a given IPv4 interface and netmask in CIDR notation.
+```js
+ipaddr.IPv4.networkAddressFromCIDR("172.0.0.1/24") == "172.0.0.0"
+```
+
+#### Conversion
+
+IPv4 and IPv6 can be converted bidirectionally to and from network byte order (MSB) byte arrays.
+
+The `fromByteArray()` method will take an array and create an appropriate IPv4 or IPv6 object
+if the input satisfies the requirements. For IPv4 it has to be an array of four 8-bit values,
+while for IPv6 it has to be an array of sixteen 8-bit values.
+
+For example:
+```js
+var addr = ipaddr.fromByteArray([0x7f, 0, 0, 1]);
+addr.toString(); // => "127.0.0.1"
+```
+
+or
+
+```js
+var addr = ipaddr.fromByteArray([0x20, 1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1])
+addr.toString(); // => "2001:db8::1"
+```
+
+Both objects also offer a `toByteArray()` method, which returns an array in network byte order (MSB).
+
+For example:
+```js
+var addr = ipaddr.parse("127.0.0.1");
+addr.toByteArray(); // => [0x7f, 0, 0, 1]
+```
+
+or
+
+```js
+var addr = ipaddr.parse("2001:db8::1");
+addr.toByteArray(); // => [0x20, 1, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]
+```
diff --git a/server/node_modules/ipaddr.js/ipaddr.min.js b/server/node_modules/ipaddr.js/ipaddr.min.js
new file mode 100644
index 0000000..b54a7cc
--- /dev/null
+++ b/server/node_modules/ipaddr.js/ipaddr.min.js
@@ -0,0 +1 @@
+(function(){var r,t,n,e,i,o,a,s;t={},s=this,"undefined"!=typeof module&&null!==module&&module.exports?module.exports=t:s.ipaddr=t,a=function(r,t,n,e){var i,o;if(r.length!==t.length)throw new Error("ipaddr: cannot match CIDR for objects with different lengths");for(i=0;e>0;){if((o=n-e)<0&&(o=0),r[i]>>o!=t[i]>>o)return!1;e-=n,i+=1}return!0},t.subnetMatch=function(r,t,n){var e,i,o,a,s;null==n&&(n="unicast");for(o in t)for(!(a=t[o])[0]||a[0]instanceof Array||(a=[a]),e=0,i=a.length;e<i;e++)if(s=a[e],r.kind()===s[0].kind()&&r.match.apply(r,s))return o;return n},t.IPv4=function(){function r(r){var t,n,e;if(4!==r.length)throw new Error("ipaddr: ipv4 octet count should be 4");for(t=0,n=r.length;t<n;t++)if(!(0<=(e=r[t])&&e<=255))throw new Error("ipaddr: ipv4 octet should fit in 8 bits");this.octets=r}return r.prototype.kind=function(){return"ipv4"},r.prototype.toString=function(){return this.octets.join(".")},r.prototype.toNormalizedString=function(){return this.toString()},r.prototype.toByteArray=function(){return this.octets.slice(0)},r.prototype.match=function(r,t){var n;if(void 0===t&&(r=(n=r)[0],t=n[1]),"ipv4"!==r.kind())throw new Error("ipaddr: cannot match ipv4 address with non-ipv4 one");return a(this.octets,r.octets,8,t)},r.prototype.SpecialRanges={unspecified:[[new r([0,0,0,0]),8]],broadcast:[[new r([255,255,255,255]),32]],multicast:[[new r([224,0,0,0]),4]],linkLocal:[[new r([169,254,0,0]),16]],loopback:[[new r([127,0,0,0]),8]],carrierGradeNat:[[new r([100,64,0,0]),10]],private:[[new r([10,0,0,0]),8],[new r([172,16,0,0]),12],[new r([192,168,0,0]),16]],reserved:[[new r([192,0,0,0]),24],[new r([192,0,2,0]),24],[new r([192,88,99,0]),24],[new r([198,51,100,0]),24],[new r([203,0,113,0]),24],[new r([240,0,0,0]),4]]},r.prototype.range=function(){return t.subnetMatch(this,this.SpecialRanges)},r.prototype.toIPv4MappedAddress=function(){return t.IPv6.parse("::ffff:"+this.toString())},r.prototype.prefixLengthFromSubnetMask=function(){var r,t,n,e,i,o,a;for(a={0:8,128:7,192:6,224:5,240:4,248:3,252:2,254:1,255:0},r=0,i=!1,t=n=3;n>=0;t=n+=-1){if(!((e=this.octets[t])in a))return null;if(o=a[e],i&&0!==o)return null;8!==o&&(i=!0),r+=o}return 32-r},r}(),n="(0?\\d+|0x[a-f0-9]+)",e={fourOctet:new RegExp("^"+n+"\\."+n+"\\."+n+"\\."+n+"$","i"),longValue:new RegExp("^"+n+"$","i")},t.IPv4.parser=function(r){var t,n,i,o,a;if(n=function(r){return"0"===r[0]&&"x"!==r[1]?parseInt(r,8):parseInt(r)},t=r.match(e.fourOctet))return function(){var r,e,o,a;for(a=[],r=0,e=(o=t.slice(1,6)).length;r<e;r++)i=o[r],a.push(n(i));return a}();if(t=r.match(e.longValue)){if((a=n(t[1]))>4294967295||a<0)throw new Error("ipaddr: address outside defined range");return function(){var r,t;for(t=[],o=r=0;r<=24;o=r+=8)t.push(a>>o&255);return t}().reverse()}return null},t.IPv6=function(){function r(r,t){var n,e,i,o,a,s;if(16===r.length)for(this.parts=[],n=e=0;e<=14;n=e+=2)this.parts.push(r[n]<<8|r[n+1]);else{if(8!==r.length)throw new Error("ipaddr: ipv6 part count should be 8 or 16");this.parts=r}for(i=0,o=(s=this.parts).length;i<o;i++)if(!(0<=(a=s[i])&&a<=65535))throw new Error("ipaddr: ipv6 part should fit in 16 bits");t&&(this.zoneId=t)}return r.prototype.kind=function(){return"ipv6"},r.prototype.toString=function(){return this.toNormalizedString().replace(/((^|:)(0(:|$))+)/,"::")},r.prototype.toRFC5952String=function(){var r,t,n,e,i;for(e=/((^|:)(0(:|$)){2,})/g,i=this.toNormalizedString(),r=0,t=-1;n=e.exec(i);)n[0].length>t&&(r=n.index,t=n[0].length);return t<0?i:i.substring(0,r)+"::"+i.substring(r+t)},r.prototype.toByteArray=function(){var r,t,n,e,i;for(r=[],t=0,n=(i=this.parts).length;t<n;t++)e=i[t],r.push(e>>8),r.push(255&e);return r},r.prototype.toNormalizedString=function(){var r,t,n;return r=function(){var r,n,e,i;for(i=[],r=0,n=(e=this.parts).length;r<n;r++)t=e[r],i.push(t.toString(16));return i}.call(this).join(":"),n="",this.zoneId&&(n="%"+this.zoneId),r+n},r.prototype.toFixedLengthString=function(){var r,t,n;return r=function(){var r,n,e,i;for(i=[],r=0,n=(e=this.parts).length;r<n;r++)t=e[r],i.push(t.toString(16).padStart(4,"0"));return i}.call(this).join(":"),n="",this.zoneId&&(n="%"+this.zoneId),r+n},r.prototype.match=function(r,t){var n;if(void 0===t&&(r=(n=r)[0],t=n[1]),"ipv6"!==r.kind())throw new Error("ipaddr: cannot match ipv6 address with non-ipv6 one");return a(this.parts,r.parts,16,t)},r.prototype.SpecialRanges={unspecified:[new r([0,0,0,0,0,0,0,0]),128],linkLocal:[new r([65152,0,0,0,0,0,0,0]),10],multicast:[new r([65280,0,0,0,0,0,0,0]),8],loopback:[new r([0,0,0,0,0,0,0,1]),128],uniqueLocal:[new r([64512,0,0,0,0,0,0,0]),7],ipv4Mapped:[new r([0,0,0,0,0,65535,0,0]),96],rfc6145:[new r([0,0,0,0,65535,0,0,0]),96],rfc6052:[new r([100,65435,0,0,0,0,0,0]),96],"6to4":[new r([8194,0,0,0,0,0,0,0]),16],teredo:[new r([8193,0,0,0,0,0,0,0]),32],reserved:[[new r([8193,3512,0,0,0,0,0,0]),32]]},r.prototype.range=function(){return t.subnetMatch(this,this.SpecialRanges)},r.prototype.isIPv4MappedAddress=function(){return"ipv4Mapped"===this.range()},r.prototype.toIPv4Address=function(){var r,n,e;if(!this.isIPv4MappedAddress())throw new Error("ipaddr: trying to convert a generic ipv6 address to ipv4");return e=this.parts.slice(-2),r=e[0],n=e[1],new t.IPv4([r>>8,255&r,n>>8,255&n])},r.prototype.prefixLengthFromSubnetMask=function(){var r,t,n,e,i,o,a;for(a={0:16,32768:15,49152:14,57344:13,61440:12,63488:11,64512:10,65024:9,65280:8,65408:7,65472:6,65504:5,65520:4,65528:3,65532:2,65534:1,65535:0},r=0,i=!1,t=n=7;n>=0;t=n+=-1){if(!((e=this.parts[t])in a))return null;if(o=a[e],i&&0!==o)return null;16!==o&&(i=!0),r+=o}return 128-r},r}(),i="(?:[0-9a-f]+::?)+",o={zoneIndex:new RegExp("%[0-9a-z]{1,}","i"),native:new RegExp("^(::)?("+i+")?([0-9a-f]+)?(::)?(%[0-9a-z]{1,})?$","i"),transitional:new RegExp("^((?:"+i+")|(?:::)(?:"+i+")?)"+n+"\\."+n+"\\."+n+"\\."+n+"(%[0-9a-z]{1,})?$","i")},r=function(r,t){var n,e,i,a,s,p;if(r.indexOf("::")!==r.lastIndexOf("::"))return null;for((p=(r.match(o.zoneIndex)||[])[0])&&(p=p.substring(1),r=r.replace(/%.+$/,"")),n=0,e=-1;(e=r.indexOf(":",e+1))>=0;)n++;if("::"===r.substr(0,2)&&n--,"::"===r.substr(-2,2)&&n--,n>t)return null;for(s=t-n,a=":";s--;)a+="0:";return":"===(r=r.replace("::",a))[0]&&(r=r.slice(1)),":"===r[r.length-1]&&(r=r.slice(0,-1)),t=function(){var t,n,e,o;for(o=[],t=0,n=(e=r.split(":")).length;t<n;t++)i=e[t],o.push(parseInt(i,16));return o}(),{parts:t,zoneId:p}},t.IPv6.parser=function(t){var n,e,i,a,s,p,u;if(o.native.test(t))return r(t,8);if((a=t.match(o.transitional))&&(u=a[6]||"",(n=r(a[1].slice(0,-1)+u,6)).parts)){for(e=0,i=(p=[parseInt(a[2]),parseInt(a[3]),parseInt(a[4]),parseInt(a[5])]).length;e<i;e++)if(!(0<=(s=p[e])&&s<=255))return null;return n.parts.push(p[0]<<8|p[1]),n.parts.push(p[2]<<8|p[3]),{parts:n.parts,zoneId:n.zoneId}}return null},t.IPv4.isIPv4=t.IPv6.isIPv6=function(r){return null!==this.parser(r)},t.IPv4.isValid=function(r){try{return new this(this.parser(r)),!0}catch(r){return r,!1}},t.IPv4.isValidFourPartDecimal=function(r){return!(!t.IPv4.isValid(r)||!r.match(/^(0|[1-9]\d*)(\.(0|[1-9]\d*)){3}$/))},t.IPv6.isValid=function(r){var t;if("string"==typeof r&&-1===r.indexOf(":"))return!1;try{return t=this.parser(r),new this(t.parts,t.zoneId),!0}catch(r){return r,!1}},t.IPv4.parse=function(r){var t;if(null===(t=this.parser(r)))throw new Error("ipaddr: string is not formatted like ip address");return new this(t)},t.IPv6.parse=function(r){var t;if(null===(t=this.parser(r)).parts)throw new Error("ipaddr: string is not formatted like ip address");return new this(t.parts,t.zoneId)},t.IPv4.parseCIDR=function(r){var t,n,e;if((n=r.match(/^(.+)\/(\d+)$/))&&(t=parseInt(n[2]))>=0&&t<=32)return e=[this.parse(n[1]),t],Object.defineProperty(e,"toString",{value:function(){return this.join("/")}}),e;throw new Error("ipaddr: string is not formatted like an IPv4 CIDR range")},t.IPv4.subnetMaskFromPrefixLength=function(r){var t,n,e;if((r=parseInt(r))<0||r>32)throw new Error("ipaddr: invalid IPv4 prefix length");for(e=[0,0,0,0],n=0,t=Math.floor(r/8);n<t;)e[n]=255,n++;return t<4&&(e[t]=Math.pow(2,r%8)-1<<8-r%8),new this(e)},t.IPv4.broadcastAddressFromCIDR=function(r){var t,n,e,i,o;try{for(e=(t=this.parseCIDR(r))[0].toByteArray(),o=this.subnetMaskFromPrefixLength(t[1]).toByteArray(),i=[],n=0;n<4;)i.push(parseInt(e[n],10)|255^parseInt(o[n],10)),n++;return new this(i)}catch(r){throw r,new Error("ipaddr: the address does not have IPv4 CIDR format")}},t.IPv4.networkAddressFromCIDR=function(r){var t,n,e,i,o;try{for(e=(t=this.parseCIDR(r))[0].toByteArray(),o=this.subnetMaskFromPrefixLength(t[1]).toByteArray(),i=[],n=0;n<4;)i.push(parseInt(e[n],10)&parseInt(o[n],10)),n++;return new this(i)}catch(r){throw r,new Error("ipaddr: the address does not have IPv4 CIDR format")}},t.IPv6.parseCIDR=function(r){var t,n,e;if((n=r.match(/^(.+)\/(\d+)$/))&&(t=parseInt(n[2]))>=0&&t<=128)return e=[this.parse(n[1]),t],Object.defineProperty(e,"toString",{value:function(){return this.join("/")}}),e;throw new Error("ipaddr: string is not formatted like an IPv6 CIDR range")},t.isValid=function(r){return t.IPv6.isValid(r)||t.IPv4.isValid(r)},t.parse=function(r){if(t.IPv6.isValid(r))return t.IPv6.parse(r);if(t.IPv4.isValid(r))return t.IPv4.parse(r);throw new Error("ipaddr: the address has neither IPv6 nor IPv4 format")},t.parseCIDR=function(r){try{return t.IPv6.parseCIDR(r)}catch(n){n;try{return t.IPv4.parseCIDR(r)}catch(r){throw r,new Error("ipaddr: the address has neither IPv6 nor IPv4 CIDR format")}}},t.fromByteArray=function(r){var n;if(4===(n=r.length))return new t.IPv4(r);if(16===n)return new t.IPv6(r);throw new Error("ipaddr: the binary input is neither an IPv6 nor IPv4 address")},t.process=function(r){var t;return t=this.parse(r),"ipv6"===t.kind()&&t.isIPv4MappedAddress()?t.toIPv4Address():t}}).call(this);
\ No newline at end of file
diff --git a/server/node_modules/ipaddr.js/lib/ipaddr.js b/server/node_modules/ipaddr.js/lib/ipaddr.js
new file mode 100644
index 0000000..18bd93b
--- /dev/null
+++ b/server/node_modules/ipaddr.js/lib/ipaddr.js
@@ -0,0 +1,673 @@
+(function() {
+  var expandIPv6, ipaddr, ipv4Part, ipv4Regexes, ipv6Part, ipv6Regexes, matchCIDR, root, zoneIndex;
+
+  ipaddr = {};
+
+  root = this;
+
+  if ((typeof module !== "undefined" && module !== null) && module.exports) {
+    module.exports = ipaddr;
+  } else {
+    root['ipaddr'] = ipaddr;
+  }
+
+  matchCIDR = function(first, second, partSize, cidrBits) {
+    var part, shift;
+    if (first.length !== second.length) {
+      throw new Error("ipaddr: cannot match CIDR for objects with different lengths");
+    }
+    part = 0;
+    while (cidrBits > 0) {
+      shift = partSize - cidrBits;
+      if (shift < 0) {
+        shift = 0;
+      }
+      if (first[part] >> shift !== second[part] >> shift) {
+        return false;
+      }
+      cidrBits -= partSize;
+      part += 1;
+    }
+    return true;
+  };
+
+  ipaddr.subnetMatch = function(address, rangeList, defaultName) {
+    var k, len, rangeName, rangeSubnets, subnet;
+    if (defaultName == null) {
+      defaultName = 'unicast';
+    }
+    for (rangeName in rangeList) {
+      rangeSubnets = rangeList[rangeName];
+      if (rangeSubnets[0] && !(rangeSubnets[0] instanceof Array)) {
+        rangeSubnets = [rangeSubnets];
+      }
+      for (k = 0, len = rangeSubnets.length; k < len; k++) {
+        subnet = rangeSubnets[k];
+        if (address.kind() === subnet[0].kind()) {
+          if (address.match.apply(address, subnet)) {
+            return rangeName;
+          }
+        }
+      }
+    }
+    return defaultName;
+  };
+
+  ipaddr.IPv4 = (function() {
+    function IPv4(octets) {
+      var k, len, octet;
+      if (octets.length !== 4) {
+        throw new Error("ipaddr: ipv4 octet count should be 4");
+      }
+      for (k = 0, len = octets.length; k < len; k++) {
+        octet = octets[k];
+        if (!((0 <= octet && octet <= 255))) {
+          throw new Error("ipaddr: ipv4 octet should fit in 8 bits");
+        }
+      }
+      this.octets = octets;
+    }
+
+    IPv4.prototype.kind = function() {
+      return 'ipv4';
+    };
+
+    IPv4.prototype.toString = function() {
+      return this.octets.join(".");
+    };
+
+    IPv4.prototype.toNormalizedString = function() {
+      return this.toString();
+    };
+
+    IPv4.prototype.toByteArray = function() {
+      return this.octets.slice(0);
+    };
+
+    IPv4.prototype.match = function(other, cidrRange) {
+      var ref;
+      if (cidrRange === void 0) {
+        ref = other, other = ref[0], cidrRange = ref[1];
+      }
+      if (other.kind() !== 'ipv4') {
+        throw new Error("ipaddr: cannot match ipv4 address with non-ipv4 one");
+      }
+      return matchCIDR(this.octets, other.octets, 8, cidrRange);
+    };
+
+    IPv4.prototype.SpecialRanges = {
+      unspecified: [[new IPv4([0, 0, 0, 0]), 8]],
+      broadcast: [[new IPv4([255, 255, 255, 255]), 32]],
+      multicast: [[new IPv4([224, 0, 0, 0]), 4]],
+      linkLocal: [[new IPv4([169, 254, 0, 0]), 16]],
+      loopback: [[new IPv4([127, 0, 0, 0]), 8]],
+      carrierGradeNat: [[new IPv4([100, 64, 0, 0]), 10]],
+      "private": [[new IPv4([10, 0, 0, 0]), 8], [new IPv4([172, 16, 0, 0]), 12], [new IPv4([192, 168, 0, 0]), 16]],
+      reserved: [[new IPv4([192, 0, 0, 0]), 24], [new IPv4([192, 0, 2, 0]), 24], [new IPv4([192, 88, 99, 0]), 24], [new IPv4([198, 51, 100, 0]), 24], [new IPv4([203, 0, 113, 0]), 24], [new IPv4([240, 0, 0, 0]), 4]]
+    };
+
+    IPv4.prototype.range = function() {
+      return ipaddr.subnetMatch(this, this.SpecialRanges);
+    };
+
+    IPv4.prototype.toIPv4MappedAddress = function() {
+      return ipaddr.IPv6.parse("::ffff:" + (this.toString()));
+    };
+
+    IPv4.prototype.prefixLengthFromSubnetMask = function() {
+      var cidr, i, k, octet, stop, zeros, zerotable;
+      zerotable = {
+        0: 8,
+        128: 7,
+        192: 6,
+        224: 5,
+        240: 4,
+        248: 3,
+        252: 2,
+        254: 1,
+        255: 0
+      };
+      cidr = 0;
+      stop = false;
+      for (i = k = 3; k >= 0; i = k += -1) {
+        octet = this.octets[i];
+        if (octet in zerotable) {
+          zeros = zerotable[octet];
+          if (stop && zeros !== 0) {
+            return null;
+          }
+          if (zeros !== 8) {
+            stop = true;
+          }
+          cidr += zeros;
+        } else {
+          return null;
+        }
+      }
+      return 32 - cidr;
+    };
+
+    return IPv4;
+
+  })();
+
+  ipv4Part = "(0?\\d+|0x[a-f0-9]+)";
+
+  ipv4Regexes = {
+    fourOctet: new RegExp("^" + ipv4Part + "\\." + ipv4Part + "\\." + ipv4Part + "\\." + ipv4Part + "$", 'i'),
+    longValue: new RegExp("^" + ipv4Part + "$", 'i')
+  };
+
+  ipaddr.IPv4.parser = function(string) {
+    var match, parseIntAuto, part, shift, value;
+    parseIntAuto = function(string) {
+      if (string[0] === "0" && string[1] !== "x") {
+        return parseInt(string, 8);
+      } else {
+        return parseInt(string);
+      }
+    };
+    if (match = string.match(ipv4Regexes.fourOctet)) {
+      return (function() {
+        var k, len, ref, results;
+        ref = match.slice(1, 6);
+        results = [];
+        for (k = 0, len = ref.length; k < len; k++) {
+          part = ref[k];
+          results.push(parseIntAuto(part));
+        }
+        return results;
+      })();
+    } else if (match = string.match(ipv4Regexes.longValue)) {
+      value = parseIntAuto(match[1]);
+      if (value > 0xffffffff || value < 0) {
+        throw new Error("ipaddr: address outside defined range");
+      }
+      return ((function() {
+        var k, results;
+        results = [];
+        for (shift = k = 0; k <= 24; shift = k += 8) {
+          results.push((value >> shift) & 0xff);
+        }
+        return results;
+      })()).reverse();
+    } else {
+      return null;
+    }
+  };
+
+  ipaddr.IPv6 = (function() {
+    function IPv6(parts, zoneId) {
+      var i, k, l, len, part, ref;
+      if (parts.length === 16) {
+        this.parts = [];
+        for (i = k = 0; k <= 14; i = k += 2) {
+          this.parts.push((parts[i] << 8) | parts[i + 1]);
+        }
+      } else if (parts.length === 8) {
+        this.parts = parts;
+      } else {
+        throw new Error("ipaddr: ipv6 part count should be 8 or 16");
+      }
+      ref = this.parts;
+      for (l = 0, len = ref.length; l < len; l++) {
+        part = ref[l];
+        if (!((0 <= part && part <= 0xffff))) {
+          throw new Error("ipaddr: ipv6 part should fit in 16 bits");
+        }
+      }
+      if (zoneId) {
+        this.zoneId = zoneId;
+      }
+    }
+
+    IPv6.prototype.kind = function() {
+      return 'ipv6';
+    };
+
+    IPv6.prototype.toString = function() {
+      return this.toNormalizedString().replace(/((^|:)(0(:|$))+)/, '::');
+    };
+
+    IPv6.prototype.toRFC5952String = function() {
+      var bestMatchIndex, bestMatchLength, match, regex, string;
+      regex = /((^|:)(0(:|$)){2,})/g;
+      string = this.toNormalizedString();
+      bestMatchIndex = 0;
+      bestMatchLength = -1;
+      while ((match = regex.exec(string))) {
+        if (match[0].length > bestMatchLength) {
+          bestMatchIndex = match.index;
+          bestMatchLength = match[0].length;
+        }
+      }
+      if (bestMatchLength < 0) {
+        return string;
+      }
+      return string.substring(0, bestMatchIndex) + '::' + string.substring(bestMatchIndex + bestMatchLength);
+    };
+
+    IPv6.prototype.toByteArray = function() {
+      var bytes, k, len, part, ref;
+      bytes = [];
+      ref = this.parts;
+      for (k = 0, len = ref.length; k < len; k++) {
+        part = ref[k];
+        bytes.push(part >> 8);
+        bytes.push(part & 0xff);
+      }
+      return bytes;
+    };
+
+    IPv6.prototype.toNormalizedString = function() {
+      var addr, part, suffix;
+      addr = ((function() {
+        var k, len, ref, results;
+        ref = this.parts;
+        results = [];
+        for (k = 0, len = ref.length; k < len; k++) {
+          part = ref[k];
+          results.push(part.toString(16));
+        }
+        return results;
+      }).call(this)).join(":");
+      suffix = '';
+      if (this.zoneId) {
+        suffix = '%' + this.zoneId;
+      }
+      return addr + suffix;
+    };
+
+    IPv6.prototype.toFixedLengthString = function() {
+      var addr, part, suffix;
+      addr = ((function() {
+        var k, len, ref, results;
+        ref = this.parts;
+        results = [];
+        for (k = 0, len = ref.length; k < len; k++) {
+          part = ref[k];
+          results.push(part.toString(16).padStart(4, '0'));
+        }
+        return results;
+      }).call(this)).join(":");
+      suffix = '';
+      if (this.zoneId) {
+        suffix = '%' + this.zoneId;
+      }
+      return addr + suffix;
+    };
+
+    IPv6.prototype.match = function(other, cidrRange) {
+      var ref;
+      if (cidrRange === void 0) {
+        ref = other, other = ref[0], cidrRange = ref[1];
+      }
+      if (other.kind() !== 'ipv6') {
+        throw new Error("ipaddr: cannot match ipv6 address with non-ipv6 one");
+      }
+      return matchCIDR(this.parts, other.parts, 16, cidrRange);
+    };
+
+    IPv6.prototype.SpecialRanges = {
+      unspecified: [new IPv6([0, 0, 0, 0, 0, 0, 0, 0]), 128],
+      linkLocal: [new IPv6([0xfe80, 0, 0, 0, 0, 0, 0, 0]), 10],
+      multicast: [new IPv6([0xff00, 0, 0, 0, 0, 0, 0, 0]), 8],
+      loopback: [new IPv6([0, 0, 0, 0, 0, 0, 0, 1]), 128],
+      uniqueLocal: [new IPv6([0xfc00, 0, 0, 0, 0, 0, 0, 0]), 7],
+      ipv4Mapped: [new IPv6([0, 0, 0, 0, 0, 0xffff, 0, 0]), 96],
+      rfc6145: [new IPv6([0, 0, 0, 0, 0xffff, 0, 0, 0]), 96],
+      rfc6052: [new IPv6([0x64, 0xff9b, 0, 0, 0, 0, 0, 0]), 96],
+      '6to4': [new IPv6([0x2002, 0, 0, 0, 0, 0, 0, 0]), 16],
+      teredo: [new IPv6([0x2001, 0, 0, 0, 0, 0, 0, 0]), 32],
+      reserved: [[new IPv6([0x2001, 0xdb8, 0, 0, 0, 0, 0, 0]), 32]]
+    };
+
+    IPv6.prototype.range = function() {
+      return ipaddr.subnetMatch(this, this.SpecialRanges);
+    };
+
+    IPv6.prototype.isIPv4MappedAddress = function() {
+      return this.range() === 'ipv4Mapped';
+    };
+
+    IPv6.prototype.toIPv4Address = function() {
+      var high, low, ref;
+      if (!this.isIPv4MappedAddress()) {
+        throw new Error("ipaddr: trying to convert a generic ipv6 address to ipv4");
+      }
+      ref = this.parts.slice(-2), high = ref[0], low = ref[1];
+      return new ipaddr.IPv4([high >> 8, high & 0xff, low >> 8, low & 0xff]);
+    };
+
+    IPv6.prototype.prefixLengthFromSubnetMask = function() {
+      var cidr, i, k, part, stop, zeros, zerotable;
+      zerotable = {
+        0: 16,
+        32768: 15,
+        49152: 14,
+        57344: 13,
+        61440: 12,
+        63488: 11,
+        64512: 10,
+        65024: 9,
+        65280: 8,
+        65408: 7,
+        65472: 6,
+        65504: 5,
+        65520: 4,
+        65528: 3,
+        65532: 2,
+        65534: 1,
+        65535: 0
+      };
+      cidr = 0;
+      stop = false;
+      for (i = k = 7; k >= 0; i = k += -1) {
+        part = this.parts[i];
+        if (part in zerotable) {
+          zeros = zerotable[part];
+          if (stop && zeros !== 0) {
+            return null;
+          }
+          if (zeros !== 16) {
+            stop = true;
+          }
+          cidr += zeros;
+        } else {
+          return null;
+        }
+      }
+      return 128 - cidr;
+    };
+
+    return IPv6;
+
+  })();
+
+  ipv6Part = "(?:[0-9a-f]+::?)+";
+
+  zoneIndex = "%[0-9a-z]{1,}";
+
+  ipv6Regexes = {
+    zoneIndex: new RegExp(zoneIndex, 'i'),
+    "native": new RegExp("^(::)?(" + ipv6Part + ")?([0-9a-f]+)?(::)?(" + zoneIndex + ")?$", 'i'),
+    transitional: new RegExp(("^((?:" + ipv6Part + ")|(?:::)(?:" + ipv6Part + ")?)") + (ipv4Part + "\\." + ipv4Part + "\\." + ipv4Part + "\\." + ipv4Part) + ("(" + zoneIndex + ")?$"), 'i')
+  };
+
+  expandIPv6 = function(string, parts) {
+    var colonCount, lastColon, part, replacement, replacementCount, zoneId;
+    if (string.indexOf('::') !== string.lastIndexOf('::')) {
+      return null;
+    }
+    zoneId = (string.match(ipv6Regexes['zoneIndex']) || [])[0];
+    if (zoneId) {
+      zoneId = zoneId.substring(1);
+      string = string.replace(/%.+$/, '');
+    }
+    colonCount = 0;
+    lastColon = -1;
+    while ((lastColon = string.indexOf(':', lastColon + 1)) >= 0) {
+      colonCount++;
+    }
+    if (string.substr(0, 2) === '::') {
+      colonCount--;
+    }
+    if (string.substr(-2, 2) === '::') {
+      colonCount--;
+    }
+    if (colonCount > parts) {
+      return null;
+    }
+    replacementCount = parts - colonCount;
+    replacement = ':';
+    while (replacementCount--) {
+      replacement += '0:';
+    }
+    string = string.replace('::', replacement);
+    if (string[0] === ':') {
+      string = string.slice(1);
+    }
+    if (string[string.length - 1] === ':') {
+      string = string.slice(0, -1);
+    }
+    parts = (function() {
+      var k, len, ref, results;
+      ref = string.split(":");
+      results = [];
+      for (k = 0, len = ref.length; k < len; k++) {
+        part = ref[k];
+        results.push(parseInt(part, 16));
+      }
+      return results;
+    })();
+    return {
+      parts: parts,
+      zoneId: zoneId
+    };
+  };
+
+  ipaddr.IPv6.parser = function(string) {
+    var addr, k, len, match, octet, octets, zoneId;
+    if (ipv6Regexes['native'].test(string)) {
+      return expandIPv6(string, 8);
+    } else if (match = string.match(ipv6Regexes['transitional'])) {
+      zoneId = match[6] || '';
+      addr = expandIPv6(match[1].slice(0, -1) + zoneId, 6);
+      if (addr.parts) {
+        octets = [parseInt(match[2]), parseInt(match[3]), parseInt(match[4]), parseInt(match[5])];
+        for (k = 0, len = octets.length; k < len; k++) {
+          octet = octets[k];
+          if (!((0 <= octet && octet <= 255))) {
+            return null;
+          }
+        }
+        addr.parts.push(octets[0] << 8 | octets[1]);
+        addr.parts.push(octets[2] << 8 | octets[3]);
+        return {
+          parts: addr.parts,
+          zoneId: addr.zoneId
+        };
+      }
+    }
+    return null;
+  };
+
+  ipaddr.IPv4.isIPv4 = ipaddr.IPv6.isIPv6 = function(string) {
+    return this.parser(string) !== null;
+  };
+
+  ipaddr.IPv4.isValid = function(string) {
+    var e;
+    try {
+      new this(this.parser(string));
+      return true;
+    } catch (error1) {
+      e = error1;
+      return false;
+    }
+  };
+
+  ipaddr.IPv4.isValidFourPartDecimal = function(string) {
+    if (ipaddr.IPv4.isValid(string) && string.match(/^(0|[1-9]\d*)(\.(0|[1-9]\d*)){3}$/)) {
+      return true;
+    } else {
+      return false;
+    }
+  };
+
+  ipaddr.IPv6.isValid = function(string) {
+    var addr, e;
+    if (typeof string === "string" && string.indexOf(":") === -1) {
+      return false;
+    }
+    try {
+      addr = this.parser(string);
+      new this(addr.parts, addr.zoneId);
+      return true;
+    } catch (error1) {
+      e = error1;
+      return false;
+    }
+  };
+
+  ipaddr.IPv4.parse = function(string) {
+    var parts;
+    parts = this.parser(string);
+    if (parts === null) {
+      throw new Error("ipaddr: string is not formatted like ip address");
+    }
+    return new this(parts);
+  };
+
+  ipaddr.IPv6.parse = function(string) {
+    var addr;
+    addr = this.parser(string);
+    if (addr.parts === null) {
+      throw new Error("ipaddr: string is not formatted like ip address");
+    }
+    return new this(addr.parts, addr.zoneId);
+  };
+
+  ipaddr.IPv4.parseCIDR = function(string) {
+    var maskLength, match, parsed;
+    if (match = string.match(/^(.+)\/(\d+)$/)) {
+      maskLength = parseInt(match[2]);
+      if (maskLength >= 0 && maskLength <= 32) {
+        parsed = [this.parse(match[1]), maskLength];
+        Object.defineProperty(parsed, 'toString', {
+          value: function() {
+            return this.join('/');
+          }
+        });
+        return parsed;
+      }
+    }
+    throw new Error("ipaddr: string is not formatted like an IPv4 CIDR range");
+  };
+
+  ipaddr.IPv4.subnetMaskFromPrefixLength = function(prefix) {
+    var filledOctetCount, j, octets;
+    prefix = parseInt(prefix);
+    if (prefix < 0 || prefix > 32) {
+      throw new Error('ipaddr: invalid IPv4 prefix length');
+    }
+    octets = [0, 0, 0, 0];
+    j = 0;
+    filledOctetCount = Math.floor(prefix / 8);
+    while (j < filledOctetCount) {
+      octets[j] = 255;
+      j++;
+    }
+    if (filledOctetCount < 4) {
+      octets[filledOctetCount] = Math.pow(2, prefix % 8) - 1 << 8 - (prefix % 8);
+    }
+    return new this(octets);
+  };
+
+  ipaddr.IPv4.broadcastAddressFromCIDR = function(string) {
+    var cidr, error, i, ipInterfaceOctets, octets, subnetMaskOctets;
+    try {
+      cidr = this.parseCIDR(string);
+      ipInterfaceOctets = cidr[0].toByteArray();
+      subnetMaskOctets = this.subnetMaskFromPrefixLength(cidr[1]).toByteArray();
+      octets = [];
+      i = 0;
+      while (i < 4) {
+        octets.push(parseInt(ipInterfaceOctets[i], 10) | parseInt(subnetMaskOctets[i], 10) ^ 255);
+        i++;
+      }
+      return new this(octets);
+    } catch (error1) {
+      error = error1;
+      throw new Error('ipaddr: the address does not have IPv4 CIDR format');
+    }
+  };
+
+  ipaddr.IPv4.networkAddressFromCIDR = function(string) {
+    var cidr, error, i, ipInterfaceOctets, octets, subnetMaskOctets;
+    try {
+      cidr = this.parseCIDR(string);
+      ipInterfaceOctets = cidr[0].toByteArray();
+      subnetMaskOctets = this.subnetMaskFromPrefixLength(cidr[1]).toByteArray();
+      octets = [];
+      i = 0;
+      while (i < 4) {
+        octets.push(parseInt(ipInterfaceOctets[i], 10) & parseInt(subnetMaskOctets[i], 10));
+        i++;
+      }
+      return new this(octets);
+    } catch (error1) {
+      error = error1;
+      throw new Error('ipaddr: the address does not have IPv4 CIDR format');
+    }
+  };
+
+  ipaddr.IPv6.parseCIDR = function(string) {
+    var maskLength, match, parsed;
+    if (match = string.match(/^(.+)\/(\d+)$/)) {
+      maskLength = parseInt(match[2]);
+      if (maskLength >= 0 && maskLength <= 128) {
+        parsed = [this.parse(match[1]), maskLength];
+        Object.defineProperty(parsed, 'toString', {
+          value: function() {
+            return this.join('/');
+          }
+        });
+        return parsed;
+      }
+    }
+    throw new Error("ipaddr: string is not formatted like an IPv6 CIDR range");
+  };
+
+  ipaddr.isValid = function(string) {
+    return ipaddr.IPv6.isValid(string) || ipaddr.IPv4.isValid(string);
+  };
+
+  ipaddr.parse = function(string) {
+    if (ipaddr.IPv6.isValid(string)) {
+      return ipaddr.IPv6.parse(string);
+    } else if (ipaddr.IPv4.isValid(string)) {
+      return ipaddr.IPv4.parse(string);
+    } else {
+      throw new Error("ipaddr: the address has neither IPv6 nor IPv4 format");
+    }
+  };
+
+  ipaddr.parseCIDR = function(string) {
+    var e;
+    try {
+      return ipaddr.IPv6.parseCIDR(string);
+    } catch (error1) {
+      e = error1;
+      try {
+        return ipaddr.IPv4.parseCIDR(string);
+      } catch (error1) {
+        e = error1;
+        throw new Error("ipaddr: the address has neither IPv6 nor IPv4 CIDR format");
+      }
+    }
+  };
+
+  ipaddr.fromByteArray = function(bytes) {
+    var length;
+    length = bytes.length;
+    if (length === 4) {
+      return new ipaddr.IPv4(bytes);
+    } else if (length === 16) {
+      return new ipaddr.IPv6(bytes);
+    } else {
+      throw new Error("ipaddr: the binary input is neither an IPv6 nor IPv4 address");
+    }
+  };
+
+  ipaddr.process = function(string) {
+    var addr;
+    addr = this.parse(string);
+    if (addr.kind() === 'ipv6' && addr.isIPv4MappedAddress()) {
+      return addr.toIPv4Address();
+    } else {
+      return addr;
+    }
+  };
+
+}).call(this);
diff --git a/server/node_modules/ipaddr.js/lib/ipaddr.js.d.ts b/server/node_modules/ipaddr.js/lib/ipaddr.js.d.ts
new file mode 100644
index 0000000..52174b6
--- /dev/null
+++ b/server/node_modules/ipaddr.js/lib/ipaddr.js.d.ts
@@ -0,0 +1,68 @@
+declare module "ipaddr.js" {
+    type IPv4Range = 'unicast' | 'unspecified' | 'broadcast' | 'multicast' | 'linkLocal' | 'loopback' | 'carrierGradeNat' | 'private' | 'reserved';
+    type IPv6Range = 'unicast' | 'unspecified' | 'linkLocal' | 'multicast' | 'loopback' | 'uniqueLocal' | 'ipv4Mapped' | 'rfc6145' | 'rfc6052' | '6to4' | 'teredo' | 'reserved';
+
+    interface RangeList<T> {
+        [name: string]: [T, number] | [T, number][];
+    }
+
+    // Common methods/properties for IPv4 and IPv6 classes.
+    class IP {
+        prefixLengthFromSubnetMask(): number | null;
+        toByteArray(): number[];
+        toNormalizedString(): string;
+        toString(): string;
+    }
+
+    namespace Address {
+        export function isValid(addr: string): boolean;
+        export function fromByteArray(bytes: number[]): IPv4 | IPv6;
+        export function parse(addr: string): IPv4 | IPv6;
+        export function parseCIDR(mask: string): [IPv4 | IPv6, number];
+        export function process(addr: string): IPv4 | IPv6;
+        export function subnetMatch(addr: IPv4, rangeList: RangeList<IPv4>, defaultName?: string): string;
+        export function subnetMatch(addr: IPv6, rangeList: RangeList<IPv6>, defaultName?: string): string;
+
+        export class IPv4 extends IP {
+            static broadcastAddressFromCIDR(addr: string): IPv4;
+            static isIPv4(addr: string): boolean;
+            static isValidFourPartDecimal(addr: string): boolean;
+            static isValid(addr: string): boolean;
+            static networkAddressFromCIDR(addr: string): IPv4;
+            static parse(addr: string): IPv4;
+            static parseCIDR(addr: string): [IPv4, number];
+            static subnetMaskFromPrefixLength(prefix: number): IPv4;
+            constructor(octets: number[]);
+            octets: number[]
+
+            kind(): 'ipv4';
+            match(addr: IPv4, bits: number): boolean;
+            match(mask: [IPv4, number]): boolean;
+            range(): IPv4Range;
+            subnetMatch(rangeList: RangeList<IPv4>, defaultName?: string): string;
+            toIPv4MappedAddress(): IPv6;
+        }
+
+        export class IPv6 extends IP {
+            static broadcastAddressFromCIDR(addr: string): IPv6;
+            static isIPv6(addr: string): boolean;
+            static isValid(addr: string): boolean;
+            static parse(addr: string): IPv6;
+            static parseCIDR(addr: string): [IPv6, number];
+            static subnetMaskFromPrefixLength(prefix: number): IPv6;
+            constructor(parts: number[]);
+            parts: number[]
+            zoneId?: string
+
+            isIPv4MappedAddress(): boolean;
+            kind(): 'ipv6';
+            match(addr: IPv6, bits: number): boolean;
+            match(mask: [IPv6, number]): boolean;
+            range(): IPv6Range;
+            subnetMatch(rangeList: RangeList<IPv6>, defaultName?: string): string;
+            toIPv4Address(): IPv4;
+        }
+    }
+
+    export = Address;
+}
diff --git a/server/node_modules/ipaddr.js/package.json b/server/node_modules/ipaddr.js/package.json
new file mode 100644
index 0000000..f4d3547
--- /dev/null
+++ b/server/node_modules/ipaddr.js/package.json
@@ -0,0 +1,35 @@
+{
+  "name": "ipaddr.js",
+  "description": "A library for manipulating IPv4 and IPv6 addresses in JavaScript.",
+  "version": "1.9.1",
+  "author": "whitequark <whitequark@whitequark.org>",
+  "directories": {
+    "lib": "./lib"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "coffee-script": "~1.12.6",
+    "nodeunit": "^0.11.3",
+    "uglify-js": "~3.0.19"
+  },
+  "scripts": {
+    "test": "cake build test"
+  },
+  "files": [
+    "lib/",
+    "LICENSE",
+    "ipaddr.min.js"
+  ],
+  "keywords": [
+    "ip",
+    "ipv4",
+    "ipv6"
+  ],
+  "repository": "git://github.com/whitequark/ipaddr.js",
+  "main": "./lib/ipaddr.js",
+  "engines": {
+    "node": ">= 0.10"
+  },
+  "license": "MIT",
+  "types": "./lib/ipaddr.js.d.ts"
+}
diff --git a/server/node_modules/is-fullwidth-code-point/index.d.ts b/server/node_modules/is-fullwidth-code-point/index.d.ts
new file mode 100644
index 0000000..729d202
--- /dev/null
+++ b/server/node_modules/is-fullwidth-code-point/index.d.ts
@@ -0,0 +1,17 @@
+/**
+Check if the character represented by a given [Unicode code point](https://en.wikipedia.org/wiki/Code_point) is [fullwidth](https://en.wikipedia.org/wiki/Halfwidth_and_fullwidth_forms).
+
+@param codePoint - The [code point](https://en.wikipedia.org/wiki/Code_point) of a character.
+
+@example
+```
+import isFullwidthCodePoint from 'is-fullwidth-code-point';
+
+isFullwidthCodePoint('谢'.codePointAt(0));
+//=> true
+
+isFullwidthCodePoint('a'.codePointAt(0));
+//=> false
+```
+*/
+export default function isFullwidthCodePoint(codePoint: number): boolean;
diff --git a/server/node_modules/is-fullwidth-code-point/index.js b/server/node_modules/is-fullwidth-code-point/index.js
new file mode 100644
index 0000000..671f97f
--- /dev/null
+++ b/server/node_modules/is-fullwidth-code-point/index.js
@@ -0,0 +1,50 @@
+/* eslint-disable yoda */
+'use strict';
+
+const isFullwidthCodePoint = codePoint => {
+	if (Number.isNaN(codePoint)) {
+		return false;
+	}
+
+	// Code points are derived from:
+	// http://www.unix.org/Public/UNIDATA/EastAsianWidth.txt
+	if (
+		codePoint >= 0x1100 && (
+			codePoint <= 0x115F || // Hangul Jamo
+			codePoint === 0x2329 || // LEFT-POINTING ANGLE BRACKET
+			codePoint === 0x232A || // RIGHT-POINTING ANGLE BRACKET
+			// CJK Radicals Supplement .. Enclosed CJK Letters and Months
+			(0x2E80 <= codePoint && codePoint <= 0x3247 && codePoint !== 0x303F) ||
+			// Enclosed CJK Letters and Months .. CJK Unified Ideographs Extension A
+			(0x3250 <= codePoint && codePoint <= 0x4DBF) ||
+			// CJK Unified Ideographs .. Yi Radicals
+			(0x4E00 <= codePoint && codePoint <= 0xA4C6) ||
+			// Hangul Jamo Extended-A
+			(0xA960 <= codePoint && codePoint <= 0xA97C) ||
+			// Hangul Syllables
+			(0xAC00 <= codePoint && codePoint <= 0xD7A3) ||
+			// CJK Compatibility Ideographs
+			(0xF900 <= codePoint && codePoint <= 0xFAFF) ||
+			// Vertical Forms
+			(0xFE10 <= codePoint && codePoint <= 0xFE19) ||
+			// CJK Compatibility Forms .. Small Form Variants
+			(0xFE30 <= codePoint && codePoint <= 0xFE6B) ||
+			// Halfwidth and Fullwidth Forms
+			(0xFF01 <= codePoint && codePoint <= 0xFF60) ||
+			(0xFFE0 <= codePoint && codePoint <= 0xFFE6) ||
+			// Kana Supplement
+			(0x1B000 <= codePoint && codePoint <= 0x1B001) ||
+			// Enclosed Ideographic Supplement
+			(0x1F200 <= codePoint && codePoint <= 0x1F251) ||
+			// CJK Unified Ideographs Extension B .. Tertiary Ideographic Plane
+			(0x20000 <= codePoint && codePoint <= 0x3FFFD)
+		)
+	) {
+		return true;
+	}
+
+	return false;
+};
+
+module.exports = isFullwidthCodePoint;
+module.exports.default = isFullwidthCodePoint;
diff --git a/server/node_modules/is-fullwidth-code-point/license b/server/node_modules/is-fullwidth-code-point/license
new file mode 100644
index 0000000..e7af2f7
--- /dev/null
+++ b/server/node_modules/is-fullwidth-code-point/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/is-fullwidth-code-point/package.json b/server/node_modules/is-fullwidth-code-point/package.json
new file mode 100644
index 0000000..2137e88
--- /dev/null
+++ b/server/node_modules/is-fullwidth-code-point/package.json
@@ -0,0 +1,42 @@
+{
+	"name": "is-fullwidth-code-point",
+	"version": "3.0.0",
+	"description": "Check if the character represented by a given Unicode code point is fullwidth",
+	"license": "MIT",
+	"repository": "sindresorhus/is-fullwidth-code-point",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=8"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd-check"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"fullwidth",
+		"full-width",
+		"full",
+		"width",
+		"unicode",
+		"character",
+		"string",
+		"codepoint",
+		"code",
+		"point",
+		"is",
+		"detect",
+		"check"
+	],
+	"devDependencies": {
+		"ava": "^1.3.1",
+		"tsd-check": "^0.5.0",
+		"xo": "^0.24.0"
+	}
+}
diff --git a/server/node_modules/is-fullwidth-code-point/readme.md b/server/node_modules/is-fullwidth-code-point/readme.md
new file mode 100644
index 0000000..4236bba
--- /dev/null
+++ b/server/node_modules/is-fullwidth-code-point/readme.md
@@ -0,0 +1,39 @@
+# is-fullwidth-code-point [![Build Status](https://travis-ci.org/sindresorhus/is-fullwidth-code-point.svg?branch=master)](https://travis-ci.org/sindresorhus/is-fullwidth-code-point)
+
+> Check if the character represented by a given [Unicode code point](https://en.wikipedia.org/wiki/Code_point) is [fullwidth](https://en.wikipedia.org/wiki/Halfwidth_and_fullwidth_forms)
+
+
+## Install
+
+```
+$ npm install is-fullwidth-code-point
+```
+
+
+## Usage
+
+```js
+const isFullwidthCodePoint = require('is-fullwidth-code-point');
+
+isFullwidthCodePoint('谢'.codePointAt(0));
+//=> true
+
+isFullwidthCodePoint('a'.codePointAt(0));
+//=> false
+```
+
+
+## API
+
+### isFullwidthCodePoint(codePoint)
+
+#### codePoint
+
+Type: `number`
+
+The [code point](https://en.wikipedia.org/wiki/Code_point) of a character.
+
+
+## License
+
+MIT © [Sindre Sorhus](https://sindresorhus.com)
diff --git a/server/node_modules/is-lambda/.npmignore b/server/node_modules/is-lambda/.npmignore
new file mode 100644
index 0000000..3c3629e
--- /dev/null
+++ b/server/node_modules/is-lambda/.npmignore
@@ -0,0 +1 @@
+node_modules
diff --git a/server/node_modules/is-lambda/.travis.yml b/server/node_modules/is-lambda/.travis.yml
new file mode 100644
index 0000000..03dcca5
--- /dev/null
+++ b/server/node_modules/is-lambda/.travis.yml
@@ -0,0 +1,8 @@
+language: node_js
+node_js:
+- '7'
+- '6'
+- '5'
+- '4'
+- '0.12'
+- '0.10'
diff --git a/server/node_modules/is-lambda/LICENSE b/server/node_modules/is-lambda/LICENSE
new file mode 100644
index 0000000..4a59c94
--- /dev/null
+++ b/server/node_modules/is-lambda/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016-2017 Thomas Watson Steen
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/is-lambda/README.md b/server/node_modules/is-lambda/README.md
new file mode 100644
index 0000000..31a8f56
--- /dev/null
+++ b/server/node_modules/is-lambda/README.md
@@ -0,0 +1,27 @@
+# is-lambda
+
+Returns `true` if the current environment is an [AWS
+Lambda](https://aws.amazon.com/lambda/) server.
+
+[![Build status](https://travis-ci.org/watson/is-lambda.svg?branch=master)](https://travis-ci.org/watson/is-lambda)
+[![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat)](https://github.com/feross/standard)
+
+## Installation
+
+```
+npm install is-lambda
+```
+
+## Usage
+
+```js
+var isLambda = require('is-lambda')
+
+if (isLambda) {
+  console.log('The code is running on a AWS Lambda')
+}
+```
+
+## License
+
+MIT
diff --git a/server/node_modules/is-lambda/index.js b/server/node_modules/is-lambda/index.js
new file mode 100644
index 0000000..b245ab1
--- /dev/null
+++ b/server/node_modules/is-lambda/index.js
@@ -0,0 +1,6 @@
+'use strict'
+
+module.exports = !!(
+  (process.env.LAMBDA_TASK_ROOT && process.env.AWS_EXECUTION_ENV) ||
+  false
+)
diff --git a/server/node_modules/is-lambda/package.json b/server/node_modules/is-lambda/package.json
new file mode 100644
index 0000000..d855089
--- /dev/null
+++ b/server/node_modules/is-lambda/package.json
@@ -0,0 +1,35 @@
+{
+  "name": "is-lambda",
+  "version": "1.0.1",
+  "description": "Detect if your code is running on an AWS Lambda server",
+  "main": "index.js",
+  "dependencies": {},
+  "devDependencies": {
+    "clear-require": "^1.0.1",
+    "standard": "^10.0.2"
+  },
+  "scripts": {
+    "test": "standard && node test.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/watson/is-lambda.git"
+  },
+  "keywords": [
+    "aws",
+    "hosting",
+    "hosted",
+    "lambda",
+    "detect"
+  ],
+  "author": "Thomas Watson Steen <w@tson.dk> (https://twitter.com/wa7son)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/watson/is-lambda/issues"
+  },
+  "homepage": "https://github.com/watson/is-lambda",
+  "coordinates": [
+    37.3859955,
+    -122.0838831
+  ]
+}
diff --git a/server/node_modules/is-lambda/test.js b/server/node_modules/is-lambda/test.js
new file mode 100644
index 0000000..e8e7325
--- /dev/null
+++ b/server/node_modules/is-lambda/test.js
@@ -0,0 +1,16 @@
+'use strict'
+
+var assert = require('assert')
+var clearRequire = require('clear-require')
+
+process.env.AWS_EXECUTION_ENV = 'AWS_Lambda_nodejs6.10'
+process.env.LAMBDA_TASK_ROOT = '/var/task'
+
+var isCI = require('./')
+assert(isCI)
+
+delete process.env.AWS_EXECUTION_ENV
+
+clearRequire('./')
+isCI = require('./')
+assert(!isCI)
diff --git a/server/node_modules/isarray/.npmignore b/server/node_modules/isarray/.npmignore
new file mode 100644
index 0000000..3c3629e
--- /dev/null
+++ b/server/node_modules/isarray/.npmignore
@@ -0,0 +1 @@
+node_modules
diff --git a/server/node_modules/isarray/.travis.yml b/server/node_modules/isarray/.travis.yml
new file mode 100644
index 0000000..cc4dba2
--- /dev/null
+++ b/server/node_modules/isarray/.travis.yml
@@ -0,0 +1,4 @@
+language: node_js
+node_js:
+  - "0.8"
+  - "0.10"
diff --git a/server/node_modules/isarray/Makefile b/server/node_modules/isarray/Makefile
new file mode 100644
index 0000000..787d56e
--- /dev/null
+++ b/server/node_modules/isarray/Makefile
@@ -0,0 +1,6 @@
+
+test:
+	@node_modules/.bin/tape test.js
+
+.PHONY: test
+
diff --git a/server/node_modules/isarray/README.md b/server/node_modules/isarray/README.md
new file mode 100644
index 0000000..16d2c59
--- /dev/null
+++ b/server/node_modules/isarray/README.md
@@ -0,0 +1,60 @@
+
+# isarray
+
+`Array#isArray` for older browsers.
+
+[![build status](https://secure.travis-ci.org/juliangruber/isarray.svg)](http://travis-ci.org/juliangruber/isarray)
+[![downloads](https://img.shields.io/npm/dm/isarray.svg)](https://www.npmjs.org/package/isarray)
+
+[![browser support](https://ci.testling.com/juliangruber/isarray.png)
+](https://ci.testling.com/juliangruber/isarray)
+
+## Usage
+
+```js
+var isArray = require('isarray');
+
+console.log(isArray([])); // => true
+console.log(isArray({})); // => false
+```
+
+## Installation
+
+With [npm](http://npmjs.org) do
+
+```bash
+$ npm install isarray
+```
+
+Then bundle for the browser with
+[browserify](https://github.com/substack/browserify).
+
+With [component](http://component.io) do
+
+```bash
+$ component install juliangruber/isarray
+```
+
+## License
+
+(MIT)
+
+Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/isarray/component.json b/server/node_modules/isarray/component.json
new file mode 100644
index 0000000..9e31b68
--- /dev/null
+++ b/server/node_modules/isarray/component.json
@@ -0,0 +1,19 @@
+{
+  "name" : "isarray",
+  "description" : "Array#isArray for older browsers",
+  "version" : "0.0.1",
+  "repository" : "juliangruber/isarray",
+  "homepage": "https://github.com/juliangruber/isarray",
+  "main" : "index.js",
+  "scripts" : [
+    "index.js"
+  ],
+  "dependencies" : {},
+  "keywords": ["browser","isarray","array"],
+  "author": {
+    "name": "Julian Gruber",
+    "email": "mail@juliangruber.com",
+    "url": "http://juliangruber.com"
+  },
+  "license": "MIT"
+}
diff --git a/server/node_modules/isarray/index.js b/server/node_modules/isarray/index.js
new file mode 100644
index 0000000..a57f634
--- /dev/null
+++ b/server/node_modules/isarray/index.js
@@ -0,0 +1,5 @@
+var toString = {}.toString;
+
+module.exports = Array.isArray || function (arr) {
+  return toString.call(arr) == '[object Array]';
+};
diff --git a/server/node_modules/isarray/package.json b/server/node_modules/isarray/package.json
new file mode 100644
index 0000000..1a4317a
--- /dev/null
+++ b/server/node_modules/isarray/package.json
@@ -0,0 +1,45 @@
+{
+  "name": "isarray",
+  "description": "Array#isArray for older browsers",
+  "version": "1.0.0",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/juliangruber/isarray.git"
+  },
+  "homepage": "https://github.com/juliangruber/isarray",
+  "main": "index.js",
+  "dependencies": {},
+  "devDependencies": {
+    "tape": "~2.13.4"
+  },
+  "keywords": [
+    "browser",
+    "isarray",
+    "array"
+  ],
+  "author": {
+    "name": "Julian Gruber",
+    "email": "mail@juliangruber.com",
+    "url": "http://juliangruber.com"
+  },
+  "license": "MIT",
+  "testling": {
+    "files": "test.js",
+    "browsers": [
+      "ie/8..latest",
+      "firefox/17..latest",
+      "firefox/nightly",
+      "chrome/22..latest",
+      "chrome/canary",
+      "opera/12..latest",
+      "opera/next",
+      "safari/5.1..latest",
+      "ipad/6.0..latest",
+      "iphone/6.0..latest",
+      "android-browser/4.2..latest"
+    ]
+  },
+  "scripts": {
+    "test": "tape test.js"
+  }
+}
diff --git a/server/node_modules/isarray/test.js b/server/node_modules/isarray/test.js
new file mode 100644
index 0000000..e0c3444
--- /dev/null
+++ b/server/node_modules/isarray/test.js
@@ -0,0 +1,20 @@
+var isArray = require('./');
+var test = require('tape');
+
+test('is array', function(t){
+  t.ok(isArray([]));
+  t.notOk(isArray({}));
+  t.notOk(isArray(null));
+  t.notOk(isArray(false));
+
+  var obj = {};
+  obj[0] = true;
+  t.notOk(isArray(obj));
+
+  var arr = [];
+  arr.foo = 'bar';
+  t.ok(isArray(arr));
+
+  t.end();
+});
+
diff --git a/server/node_modules/isexe/.npmignore b/server/node_modules/isexe/.npmignore
new file mode 100644
index 0000000..c1cb757
--- /dev/null
+++ b/server/node_modules/isexe/.npmignore
@@ -0,0 +1,2 @@
+.nyc_output/
+coverage/
diff --git a/server/node_modules/isexe/LICENSE b/server/node_modules/isexe/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/isexe/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/isexe/README.md b/server/node_modules/isexe/README.md
new file mode 100644
index 0000000..35769e8
--- /dev/null
+++ b/server/node_modules/isexe/README.md
@@ -0,0 +1,51 @@
+# isexe
+
+Minimal module to check if a file is executable, and a normal file.
+
+Uses `fs.stat` and tests against the `PATHEXT` environment variable on
+Windows.
+
+## USAGE
+
+```javascript
+var isexe = require('isexe')
+isexe('some-file-name', function (err, isExe) {
+  if (err) {
+    console.error('probably file does not exist or something', err)
+  } else if (isExe) {
+    console.error('this thing can be run')
+  } else {
+    console.error('cannot be run')
+  }
+})
+
+// same thing but synchronous, throws errors
+var isExe = isexe.sync('some-file-name')
+
+// treat errors as just "not executable"
+isexe('maybe-missing-file', { ignoreErrors: true }, callback)
+var isExe = isexe.sync('maybe-missing-file', { ignoreErrors: true })
+```
+
+## API
+
+### `isexe(path, [options], [callback])`
+
+Check if the path is executable.  If no callback provided, and a
+global `Promise` object is available, then a Promise will be returned.
+
+Will raise whatever errors may be raised by `fs.stat`, unless
+`options.ignoreErrors` is set to true.
+
+### `isexe.sync(path, [options])`
+
+Same as `isexe` but returns the value and throws any errors raised.
+
+### Options
+
+* `ignoreErrors` Treat all errors as "no, this is not executable", but
+  don't raise them.
+* `uid` Number to use as the user id
+* `gid` Number to use as the group id
+* `pathExt` List of path extensions to use instead of `PATHEXT`
+  environment variable on Windows.
diff --git a/server/node_modules/isexe/index.js b/server/node_modules/isexe/index.js
new file mode 100644
index 0000000..553fb32
--- /dev/null
+++ b/server/node_modules/isexe/index.js
@@ -0,0 +1,57 @@
+var fs = require('fs')
+var core
+if (process.platform === 'win32' || global.TESTING_WINDOWS) {
+  core = require('./windows.js')
+} else {
+  core = require('./mode.js')
+}
+
+module.exports = isexe
+isexe.sync = sync
+
+function isexe (path, options, cb) {
+  if (typeof options === 'function') {
+    cb = options
+    options = {}
+  }
+
+  if (!cb) {
+    if (typeof Promise !== 'function') {
+      throw new TypeError('callback not provided')
+    }
+
+    return new Promise(function (resolve, reject) {
+      isexe(path, options || {}, function (er, is) {
+        if (er) {
+          reject(er)
+        } else {
+          resolve(is)
+        }
+      })
+    })
+  }
+
+  core(path, options || {}, function (er, is) {
+    // ignore EACCES because that just means we aren't allowed to run it
+    if (er) {
+      if (er.code === 'EACCES' || options && options.ignoreErrors) {
+        er = null
+        is = false
+      }
+    }
+    cb(er, is)
+  })
+}
+
+function sync (path, options) {
+  // my kingdom for a filtered catch
+  try {
+    return core.sync(path, options || {})
+  } catch (er) {
+    if (options && options.ignoreErrors || er.code === 'EACCES') {
+      return false
+    } else {
+      throw er
+    }
+  }
+}
diff --git a/server/node_modules/isexe/mode.js b/server/node_modules/isexe/mode.js
new file mode 100644
index 0000000..1995ea4
--- /dev/null
+++ b/server/node_modules/isexe/mode.js
@@ -0,0 +1,41 @@
+module.exports = isexe
+isexe.sync = sync
+
+var fs = require('fs')
+
+function isexe (path, options, cb) {
+  fs.stat(path, function (er, stat) {
+    cb(er, er ? false : checkStat(stat, options))
+  })
+}
+
+function sync (path, options) {
+  return checkStat(fs.statSync(path), options)
+}
+
+function checkStat (stat, options) {
+  return stat.isFile() && checkMode(stat, options)
+}
+
+function checkMode (stat, options) {
+  var mod = stat.mode
+  var uid = stat.uid
+  var gid = stat.gid
+
+  var myUid = options.uid !== undefined ?
+    options.uid : process.getuid && process.getuid()
+  var myGid = options.gid !== undefined ?
+    options.gid : process.getgid && process.getgid()
+
+  var u = parseInt('100', 8)
+  var g = parseInt('010', 8)
+  var o = parseInt('001', 8)
+  var ug = u | g
+
+  var ret = (mod & o) ||
+    (mod & g) && gid === myGid ||
+    (mod & u) && uid === myUid ||
+    (mod & ug) && myUid === 0
+
+  return ret
+}
diff --git a/server/node_modules/isexe/package.json b/server/node_modules/isexe/package.json
new file mode 100644
index 0000000..e452689
--- /dev/null
+++ b/server/node_modules/isexe/package.json
@@ -0,0 +1,31 @@
+{
+  "name": "isexe",
+  "version": "2.0.0",
+  "description": "Minimal module to check if a file is executable.",
+  "main": "index.js",
+  "directories": {
+    "test": "test"
+  },
+  "devDependencies": {
+    "mkdirp": "^0.5.1",
+    "rimraf": "^2.5.0",
+    "tap": "^10.3.0"
+  },
+  "scripts": {
+    "test": "tap test/*.js --100",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --all; git push origin --tags"
+  },
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/isaacs/isexe.git"
+  },
+  "keywords": [],
+  "bugs": {
+    "url": "https://github.com/isaacs/isexe/issues"
+  },
+  "homepage": "https://github.com/isaacs/isexe#readme"
+}
diff --git a/server/node_modules/isexe/test/basic.js b/server/node_modules/isexe/test/basic.js
new file mode 100644
index 0000000..d926df6
--- /dev/null
+++ b/server/node_modules/isexe/test/basic.js
@@ -0,0 +1,221 @@
+var t = require('tap')
+var fs = require('fs')
+var path = require('path')
+var fixture = path.resolve(__dirname, 'fixtures')
+var meow = fixture + '/meow.cat'
+var mine = fixture + '/mine.cat'
+var ours = fixture + '/ours.cat'
+var fail = fixture + '/fail.false'
+var noent = fixture + '/enoent.exe'
+var mkdirp = require('mkdirp')
+var rimraf = require('rimraf')
+
+var isWindows = process.platform === 'win32'
+var hasAccess = typeof fs.access === 'function'
+var winSkip = isWindows && 'windows'
+var accessSkip = !hasAccess && 'no fs.access function'
+var hasPromise = typeof Promise === 'function'
+var promiseSkip = !hasPromise && 'no global Promise'
+
+function reset () {
+  delete require.cache[require.resolve('../')]
+  return require('../')
+}
+
+t.test('setup fixtures', function (t) {
+  rimraf.sync(fixture)
+  mkdirp.sync(fixture)
+  fs.writeFileSync(meow, '#!/usr/bin/env cat\nmeow\n')
+  fs.chmodSync(meow, parseInt('0755', 8))
+  fs.writeFileSync(fail, '#!/usr/bin/env false\n')
+  fs.chmodSync(fail, parseInt('0644', 8))
+  fs.writeFileSync(mine, '#!/usr/bin/env cat\nmine\n')
+  fs.chmodSync(mine, parseInt('0744', 8))
+  fs.writeFileSync(ours, '#!/usr/bin/env cat\nours\n')
+  fs.chmodSync(ours, parseInt('0754', 8))
+  t.end()
+})
+
+t.test('promise', { skip: promiseSkip }, function (t) {
+  var isexe = reset()
+  t.test('meow async', function (t) {
+    isexe(meow).then(function (is) {
+      t.ok(is)
+      t.end()
+    })
+  })
+  t.test('fail async', function (t) {
+    isexe(fail).then(function (is) {
+      t.notOk(is)
+      t.end()
+    })
+  })
+  t.test('noent async', function (t) {
+    isexe(noent).catch(function (er) {
+      t.ok(er)
+      t.end()
+    })
+  })
+  t.test('noent ignore async', function (t) {
+    isexe(noent, { ignoreErrors: true }).then(function (is) {
+      t.notOk(is)
+      t.end()
+    })
+  })
+  t.end()
+})
+
+t.test('no promise', function (t) {
+  global.Promise = null
+  var isexe = reset()
+  t.throws('try to meow a promise', function () {
+    isexe(meow)
+  })
+  t.end()
+})
+
+t.test('access', { skip: accessSkip || winSkip }, function (t) {
+  runTest(t)
+})
+
+t.test('mode', { skip: winSkip }, function (t) {
+  delete fs.access
+  delete fs.accessSync
+  var isexe = reset()
+  t.ok(isexe.sync(ours, { uid: 0, gid: 0 }))
+  t.ok(isexe.sync(mine, { uid: 0, gid: 0 }))
+  runTest(t)
+})
+
+t.test('windows', function (t) {
+  global.TESTING_WINDOWS = true
+  var pathExt = '.EXE;.CAT;.CMD;.COM'
+  t.test('pathExt option', function (t) {
+    runTest(t, { pathExt: '.EXE;.CAT;.CMD;.COM' })
+  })
+  t.test('pathExt env', function (t) {
+    process.env.PATHEXT = pathExt
+    runTest(t)
+  })
+  t.test('no pathExt', function (t) {
+    // with a pathExt of '', any filename is fine.
+    // so the "fail" one would still pass.
+    runTest(t, { pathExt: '', skipFail: true })
+  })
+  t.test('pathext with empty entry', function (t) {
+    // with a pathExt of '', any filename is fine.
+    // so the "fail" one would still pass.
+    runTest(t, { pathExt: ';' + pathExt, skipFail: true })
+  })
+  t.end()
+})
+
+t.test('cleanup', function (t) {
+  rimraf.sync(fixture)
+  t.end()
+})
+
+function runTest (t, options) {
+  var isexe = reset()
+
+  var optionsIgnore = Object.create(options || {})
+  optionsIgnore.ignoreErrors = true
+
+  if (!options || !options.skipFail) {
+    t.notOk(isexe.sync(fail, options))
+  }
+  t.notOk(isexe.sync(noent, optionsIgnore))
+  if (!options) {
+    t.ok(isexe.sync(meow))
+  } else {
+    t.ok(isexe.sync(meow, options))
+  }
+
+  t.ok(isexe.sync(mine, options))
+  t.ok(isexe.sync(ours, options))
+  t.throws(function () {
+    isexe.sync(noent, options)
+  })
+
+  t.test('meow async', function (t) {
+    if (!options) {
+      isexe(meow, function (er, is) {
+        if (er) {
+          throw er
+        }
+        t.ok(is)
+        t.end()
+      })
+    } else {
+      isexe(meow, options, function (er, is) {
+        if (er) {
+          throw er
+        }
+        t.ok(is)
+        t.end()
+      })
+    }
+  })
+
+  t.test('mine async', function (t) {
+    isexe(mine, options, function (er, is) {
+      if (er) {
+        throw er
+      }
+      t.ok(is)
+      t.end()
+    })
+  })
+
+  t.test('ours async', function (t) {
+    isexe(ours, options, function (er, is) {
+      if (er) {
+        throw er
+      }
+      t.ok(is)
+      t.end()
+    })
+  })
+
+  if (!options || !options.skipFail) {
+    t.test('fail async', function (t) {
+      isexe(fail, options, function (er, is) {
+        if (er) {
+          throw er
+        }
+        t.notOk(is)
+        t.end()
+      })
+    })
+  }
+
+  t.test('noent async', function (t) {
+    isexe(noent, options, function (er, is) {
+      t.ok(er)
+      t.notOk(is)
+      t.end()
+    })
+  })
+
+  t.test('noent ignore async', function (t) {
+    isexe(noent, optionsIgnore, function (er, is) {
+      if (er) {
+        throw er
+      }
+      t.notOk(is)
+      t.end()
+    })
+  })
+
+  t.test('directory is not executable', function (t) {
+    isexe(__dirname, options, function (er, is) {
+      if (er) {
+        throw er
+      }
+      t.notOk(is)
+      t.end()
+    })
+  })
+
+  t.end()
+}
diff --git a/server/node_modules/isexe/windows.js b/server/node_modules/isexe/windows.js
new file mode 100644
index 0000000..3499673
--- /dev/null
+++ b/server/node_modules/isexe/windows.js
@@ -0,0 +1,42 @@
+module.exports = isexe
+isexe.sync = sync
+
+var fs = require('fs')
+
+function checkPathExt (path, options) {
+  var pathext = options.pathExt !== undefined ?
+    options.pathExt : process.env.PATHEXT
+
+  if (!pathext) {
+    return true
+  }
+
+  pathext = pathext.split(';')
+  if (pathext.indexOf('') !== -1) {
+    return true
+  }
+  for (var i = 0; i < pathext.length; i++) {
+    var p = pathext[i].toLowerCase()
+    if (p && path.substr(-p.length).toLowerCase() === p) {
+      return true
+    }
+  }
+  return false
+}
+
+function checkStat (stat, path, options) {
+  if (!stat.isSymbolicLink() && !stat.isFile()) {
+    return false
+  }
+  return checkPathExt(path, options)
+}
+
+function isexe (path, options, cb) {
+  fs.stat(path, function (er, stat) {
+    cb(er, er ? false : checkStat(stat, path, options))
+  })
+}
+
+function sync (path, options) {
+  return checkStat(fs.statSync(path), path, options)
+}
diff --git a/server/node_modules/lru-cache/LICENSE b/server/node_modules/lru-cache/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/lru-cache/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/lru-cache/README.md b/server/node_modules/lru-cache/README.md
new file mode 100644
index 0000000..435dfeb
--- /dev/null
+++ b/server/node_modules/lru-cache/README.md
@@ -0,0 +1,166 @@
+# lru cache
+
+A cache object that deletes the least-recently-used items.
+
+[![Build Status](https://travis-ci.org/isaacs/node-lru-cache.svg?branch=master)](https://travis-ci.org/isaacs/node-lru-cache) [![Coverage Status](https://coveralls.io/repos/isaacs/node-lru-cache/badge.svg?service=github)](https://coveralls.io/github/isaacs/node-lru-cache)
+
+## Installation:
+
+```javascript
+npm install lru-cache --save
+```
+
+## Usage:
+
+```javascript
+var LRU = require("lru-cache")
+  , options = { max: 500
+              , length: function (n, key) { return n * 2 + key.length }
+              , dispose: function (key, n) { n.close() }
+              , maxAge: 1000 * 60 * 60 }
+  , cache = new LRU(options)
+  , otherCache = new LRU(50) // sets just the max size
+
+cache.set("key", "value")
+cache.get("key") // "value"
+
+// non-string keys ARE fully supported
+// but note that it must be THE SAME object, not
+// just a JSON-equivalent object.
+var someObject = { a: 1 }
+cache.set(someObject, 'a value')
+// Object keys are not toString()-ed
+cache.set('[object Object]', 'a different value')
+assert.equal(cache.get(someObject), 'a value')
+// A similar object with same keys/values won't work,
+// because it's a different object identity
+assert.equal(cache.get({ a: 1 }), undefined)
+
+cache.reset()    // empty the cache
+```
+
+If you put more stuff in it, then items will fall out.
+
+If you try to put an oversized thing in it, then it'll fall out right
+away.
+
+## Options
+
+* `max` The maximum size of the cache, checked by applying the length
+  function to all values in the cache.  Not setting this is kind of
+  silly, since that's the whole purpose of this lib, but it defaults
+  to `Infinity`.  Setting it to a non-number or negative number will
+  throw a `TypeError`.  Setting it to 0 makes it be `Infinity`.
+* `maxAge` Maximum age in ms.  Items are not pro-actively pruned out
+  as they age, but if you try to get an item that is too old, it'll
+  drop it and return undefined instead of giving it to you.
+  Setting this to a negative value will make everything seem old!
+  Setting it to a non-number will throw a `TypeError`.
+* `length` Function that is used to calculate the length of stored
+  items.  If you're storing strings or buffers, then you probably want
+  to do something like `function(n, key){return n.length}`.  The default is
+  `function(){return 1}`, which is fine if you want to store `max`
+  like-sized things.  The item is passed as the first argument, and
+  the key is passed as the second argumnet.
+* `dispose` Function that is called on items when they are dropped
+  from the cache.  This can be handy if you want to close file
+  descriptors or do other cleanup tasks when items are no longer
+  accessible.  Called with `key, value`.  It's called *before*
+  actually removing the item from the internal cache, so if you want
+  to immediately put it back in, you'll have to do that in a
+  `nextTick` or `setTimeout` callback or it won't do anything.
+* `stale` By default, if you set a `maxAge`, it'll only actually pull
+  stale items out of the cache when you `get(key)`.  (That is, it's
+  not pre-emptively doing a `setTimeout` or anything.)  If you set
+  `stale:true`, it'll return the stale value before deleting it.  If
+  you don't set this, then it'll return `undefined` when you try to
+  get a stale entry, as if it had already been deleted.
+* `noDisposeOnSet` By default, if you set a `dispose()` method, then
+  it'll be called whenever a `set()` operation overwrites an existing
+  key.  If you set this option, `dispose()` will only be called when a
+  key falls out of the cache, not when it is overwritten.
+* `updateAgeOnGet` When using time-expiring entries with `maxAge`,
+  setting this to `true` will make each item's effective time update
+  to the current time whenever it is retrieved from cache, causing it
+  to not expire.  (It can still fall out of cache based on recency of
+  use, of course.)
+
+## API
+
+* `set(key, value, maxAge)`
+* `get(key) => value`
+
+    Both of these will update the "recently used"-ness of the key.
+    They do what you think. `maxAge` is optional and overrides the
+    cache `maxAge` option if provided.
+
+    If the key is not found, `get()` will return `undefined`.
+
+    The key and val can be any value.
+
+* `peek(key)`
+
+    Returns the key value (or `undefined` if not found) without
+    updating the "recently used"-ness of the key.
+
+    (If you find yourself using this a lot, you *might* be using the
+    wrong sort of data structure, but there are some use cases where
+    it's handy.)
+
+* `del(key)`
+
+    Deletes a key out of the cache.
+
+* `reset()`
+
+    Clear the cache entirely, throwing away all values.
+
+* `has(key)`
+
+    Check if a key is in the cache, without updating the recent-ness
+    or deleting it for being stale.
+
+* `forEach(function(value,key,cache), [thisp])`
+
+    Just like `Array.prototype.forEach`.  Iterates over all the keys
+    in the cache, in order of recent-ness.  (Ie, more recently used
+    items are iterated over first.)
+
+* `rforEach(function(value,key,cache), [thisp])`
+
+    The same as `cache.forEach(...)` but items are iterated over in
+    reverse order.  (ie, less recently used items are iterated over
+    first.)
+
+* `keys()`
+
+    Return an array of the keys in the cache.
+
+* `values()`
+
+    Return an array of the values in the cache.
+
+* `length`
+
+    Return total length of objects in cache taking into account
+    `length` options function.
+
+* `itemCount`
+
+    Return total quantity of objects currently in cache. Note, that
+    `stale` (see options) items are returned as part of this item
+    count.
+
+* `dump()`
+
+    Return an array of the cache entries ready for serialization and usage
+    with 'destinationCache.load(arr)`.
+
+* `load(cacheEntriesArray)`
+
+    Loads another cache entries array, obtained with `sourceCache.dump()`,
+    into the cache. The destination cache is reset before loading new entries
+
+* `prune()`
+
+    Manually iterates over the entire cache proactively pruning old entries
diff --git a/server/node_modules/lru-cache/index.js b/server/node_modules/lru-cache/index.js
new file mode 100644
index 0000000..573b6b8
--- /dev/null
+++ b/server/node_modules/lru-cache/index.js
@@ -0,0 +1,334 @@
+'use strict'
+
+// A linked list to keep track of recently-used-ness
+const Yallist = require('yallist')
+
+const MAX = Symbol('max')
+const LENGTH = Symbol('length')
+const LENGTH_CALCULATOR = Symbol('lengthCalculator')
+const ALLOW_STALE = Symbol('allowStale')
+const MAX_AGE = Symbol('maxAge')
+const DISPOSE = Symbol('dispose')
+const NO_DISPOSE_ON_SET = Symbol('noDisposeOnSet')
+const LRU_LIST = Symbol('lruList')
+const CACHE = Symbol('cache')
+const UPDATE_AGE_ON_GET = Symbol('updateAgeOnGet')
+
+const naiveLength = () => 1
+
+// lruList is a yallist where the head is the youngest
+// item, and the tail is the oldest.  the list contains the Hit
+// objects as the entries.
+// Each Hit object has a reference to its Yallist.Node.  This
+// never changes.
+//
+// cache is a Map (or PseudoMap) that matches the keys to
+// the Yallist.Node object.
+class LRUCache {
+  constructor (options) {
+    if (typeof options === 'number')
+      options = { max: options }
+
+    if (!options)
+      options = {}
+
+    if (options.max && (typeof options.max !== 'number' || options.max < 0))
+      throw new TypeError('max must be a non-negative number')
+    // Kind of weird to have a default max of Infinity, but oh well.
+    const max = this[MAX] = options.max || Infinity
+
+    const lc = options.length || naiveLength
+    this[LENGTH_CALCULATOR] = (typeof lc !== 'function') ? naiveLength : lc
+    this[ALLOW_STALE] = options.stale || false
+    if (options.maxAge && typeof options.maxAge !== 'number')
+      throw new TypeError('maxAge must be a number')
+    this[MAX_AGE] = options.maxAge || 0
+    this[DISPOSE] = options.dispose
+    this[NO_DISPOSE_ON_SET] = options.noDisposeOnSet || false
+    this[UPDATE_AGE_ON_GET] = options.updateAgeOnGet || false
+    this.reset()
+  }
+
+  // resize the cache when the max changes.
+  set max (mL) {
+    if (typeof mL !== 'number' || mL < 0)
+      throw new TypeError('max must be a non-negative number')
+
+    this[MAX] = mL || Infinity
+    trim(this)
+  }
+  get max () {
+    return this[MAX]
+  }
+
+  set allowStale (allowStale) {
+    this[ALLOW_STALE] = !!allowStale
+  }
+  get allowStale () {
+    return this[ALLOW_STALE]
+  }
+
+  set maxAge (mA) {
+    if (typeof mA !== 'number')
+      throw new TypeError('maxAge must be a non-negative number')
+
+    this[MAX_AGE] = mA
+    trim(this)
+  }
+  get maxAge () {
+    return this[MAX_AGE]
+  }
+
+  // resize the cache when the lengthCalculator changes.
+  set lengthCalculator (lC) {
+    if (typeof lC !== 'function')
+      lC = naiveLength
+
+    if (lC !== this[LENGTH_CALCULATOR]) {
+      this[LENGTH_CALCULATOR] = lC
+      this[LENGTH] = 0
+      this[LRU_LIST].forEach(hit => {
+        hit.length = this[LENGTH_CALCULATOR](hit.value, hit.key)
+        this[LENGTH] += hit.length
+      })
+    }
+    trim(this)
+  }
+  get lengthCalculator () { return this[LENGTH_CALCULATOR] }
+
+  get length () { return this[LENGTH] }
+  get itemCount () { return this[LRU_LIST].length }
+
+  rforEach (fn, thisp) {
+    thisp = thisp || this
+    for (let walker = this[LRU_LIST].tail; walker !== null;) {
+      const prev = walker.prev
+      forEachStep(this, fn, walker, thisp)
+      walker = prev
+    }
+  }
+
+  forEach (fn, thisp) {
+    thisp = thisp || this
+    for (let walker = this[LRU_LIST].head; walker !== null;) {
+      const next = walker.next
+      forEachStep(this, fn, walker, thisp)
+      walker = next
+    }
+  }
+
+  keys () {
+    return this[LRU_LIST].toArray().map(k => k.key)
+  }
+
+  values () {
+    return this[LRU_LIST].toArray().map(k => k.value)
+  }
+
+  reset () {
+    if (this[DISPOSE] &&
+        this[LRU_LIST] &&
+        this[LRU_LIST].length) {
+      this[LRU_LIST].forEach(hit => this[DISPOSE](hit.key, hit.value))
+    }
+
+    this[CACHE] = new Map() // hash of items by key
+    this[LRU_LIST] = new Yallist() // list of items in order of use recency
+    this[LENGTH] = 0 // length of items in the list
+  }
+
+  dump () {
+    return this[LRU_LIST].map(hit =>
+      isStale(this, hit) ? false : {
+        k: hit.key,
+        v: hit.value,
+        e: hit.now + (hit.maxAge || 0)
+      }).toArray().filter(h => h)
+  }
+
+  dumpLru () {
+    return this[LRU_LIST]
+  }
+
+  set (key, value, maxAge) {
+    maxAge = maxAge || this[MAX_AGE]
+
+    if (maxAge && typeof maxAge !== 'number')
+      throw new TypeError('maxAge must be a number')
+
+    const now = maxAge ? Date.now() : 0
+    const len = this[LENGTH_CALCULATOR](value, key)
+
+    if (this[CACHE].has(key)) {
+      if (len > this[MAX]) {
+        del(this, this[CACHE].get(key))
+        return false
+      }
+
+      const node = this[CACHE].get(key)
+      const item = node.value
+
+      // dispose of the old one before overwriting
+      // split out into 2 ifs for better coverage tracking
+      if (this[DISPOSE]) {
+        if (!this[NO_DISPOSE_ON_SET])
+          this[DISPOSE](key, item.value)
+      }
+
+      item.now = now
+      item.maxAge = maxAge
+      item.value = value
+      this[LENGTH] += len - item.length
+      item.length = len
+      this.get(key)
+      trim(this)
+      return true
+    }
+
+    const hit = new Entry(key, value, len, now, maxAge)
+
+    // oversized objects fall out of cache automatically.
+    if (hit.length > this[MAX]) {
+      if (this[DISPOSE])
+        this[DISPOSE](key, value)
+
+      return false
+    }
+
+    this[LENGTH] += hit.length
+    this[LRU_LIST].unshift(hit)
+    this[CACHE].set(key, this[LRU_LIST].head)
+    trim(this)
+    return true
+  }
+
+  has (key) {
+    if (!this[CACHE].has(key)) return false
+    const hit = this[CACHE].get(key).value
+    return !isStale(this, hit)
+  }
+
+  get (key) {
+    return get(this, key, true)
+  }
+
+  peek (key) {
+    return get(this, key, false)
+  }
+
+  pop () {
+    const node = this[LRU_LIST].tail
+    if (!node)
+      return null
+
+    del(this, node)
+    return node.value
+  }
+
+  del (key) {
+    del(this, this[CACHE].get(key))
+  }
+
+  load (arr) {
+    // reset the cache
+    this.reset()
+
+    const now = Date.now()
+    // A previous serialized cache has the most recent items first
+    for (let l = arr.length - 1; l >= 0; l--) {
+      const hit = arr[l]
+      const expiresAt = hit.e || 0
+      if (expiresAt === 0)
+        // the item was created without expiration in a non aged cache
+        this.set(hit.k, hit.v)
+      else {
+        const maxAge = expiresAt - now
+        // dont add already expired items
+        if (maxAge > 0) {
+          this.set(hit.k, hit.v, maxAge)
+        }
+      }
+    }
+  }
+
+  prune () {
+    this[CACHE].forEach((value, key) => get(this, key, false))
+  }
+}
+
+const get = (self, key, doUse) => {
+  const node = self[CACHE].get(key)
+  if (node) {
+    const hit = node.value
+    if (isStale(self, hit)) {
+      del(self, node)
+      if (!self[ALLOW_STALE])
+        return undefined
+    } else {
+      if (doUse) {
+        if (self[UPDATE_AGE_ON_GET])
+          node.value.now = Date.now()
+        self[LRU_LIST].unshiftNode(node)
+      }
+    }
+    return hit.value
+  }
+}
+
+const isStale = (self, hit) => {
+  if (!hit || (!hit.maxAge && !self[MAX_AGE]))
+    return false
+
+  const diff = Date.now() - hit.now
+  return hit.maxAge ? diff > hit.maxAge
+    : self[MAX_AGE] && (diff > self[MAX_AGE])
+}
+
+const trim = self => {
+  if (self[LENGTH] > self[MAX]) {
+    for (let walker = self[LRU_LIST].tail;
+      self[LENGTH] > self[MAX] && walker !== null;) {
+      // We know that we're about to delete this one, and also
+      // what the next least recently used key will be, so just
+      // go ahead and set it now.
+      const prev = walker.prev
+      del(self, walker)
+      walker = prev
+    }
+  }
+}
+
+const del = (self, node) => {
+  if (node) {
+    const hit = node.value
+    if (self[DISPOSE])
+      self[DISPOSE](hit.key, hit.value)
+
+    self[LENGTH] -= hit.length
+    self[CACHE].delete(hit.key)
+    self[LRU_LIST].removeNode(node)
+  }
+}
+
+class Entry {
+  constructor (key, value, length, now, maxAge) {
+    this.key = key
+    this.value = value
+    this.length = length
+    this.now = now
+    this.maxAge = maxAge || 0
+  }
+}
+
+const forEachStep = (self, fn, node, thisp) => {
+  let hit = node.value
+  if (isStale(self, hit)) {
+    del(self, node)
+    if (!self[ALLOW_STALE])
+      hit = undefined
+  }
+  if (hit)
+    fn.call(thisp, hit.value, hit.key, self)
+}
+
+module.exports = LRUCache
diff --git a/server/node_modules/lru-cache/package.json b/server/node_modules/lru-cache/package.json
new file mode 100644
index 0000000..43b7502
--- /dev/null
+++ b/server/node_modules/lru-cache/package.json
@@ -0,0 +1,34 @@
+{
+  "name": "lru-cache",
+  "description": "A cache object that deletes the least-recently-used items.",
+  "version": "6.0.0",
+  "author": "Isaac Z. Schlueter <i@izs.me>",
+  "keywords": [
+    "mru",
+    "lru",
+    "cache"
+  ],
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags"
+  },
+  "main": "index.js",
+  "repository": "git://github.com/isaacs/node-lru-cache.git",
+  "devDependencies": {
+    "benchmark": "^2.1.4",
+    "tap": "^14.10.7"
+  },
+  "license": "ISC",
+  "dependencies": {
+    "yallist": "^4.0.0"
+  },
+  "files": [
+    "index.js"
+  ],
+  "engines": {
+    "node": ">=10"
+  }
+}
diff --git a/server/node_modules/make-fetch-happen/LICENSE b/server/node_modules/make-fetch-happen/LICENSE
new file mode 100644
index 0000000..8d28acf
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/LICENSE
@@ -0,0 +1,16 @@
+ISC License
+
+Copyright (c) npm, Inc.
+
+Permission to use, copy, modify, and/or distribute this software for
+any purpose with or without fee is hereby granted, provided that the
+above copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE COPYRIGHT HOLDER DISCLAIMS
+ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/make-fetch-happen/README.md b/server/node_modules/make-fetch-happen/README.md
new file mode 100644
index 0000000..87659c9
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/README.md
@@ -0,0 +1,395 @@
+# make-fetch-happen
+[![npm version](https://img.shields.io/npm/v/make-fetch-happen.svg)](https://npm.im/make-fetch-happen) [![license](https://img.shields.io/npm/l/make-fetch-happen.svg)](https://npm.im/make-fetch-happen) [![Travis](https://img.shields.io/travis/npm/make-fetch-happen.svg)](https://travis-ci.org/npm/make-fetch-happen) [![Coverage Status](https://coveralls.io/repos/github/npm/make-fetch-happen/badge.svg?branch=latest)](https://coveralls.io/github/npm/make-fetch-happen?branch=latest)
+
+[`make-fetch-happen`](https://github.com/npm/make-fetch-happen) is a Node.js
+library that wraps [`minipass-fetch`](https://github.com/npm/minipass-fetch) with additional
+features [`minipass-fetch`](https://github.com/npm/minipass-fetch) doesn't intend to include, including HTTP Cache support, request
+pooling, proxies, retries, [and more](#features)!
+
+## Install
+
+`$ npm install --save make-fetch-happen`
+
+## Table of Contents
+
+* [Example](#example)
+* [Features](#features)
+* [Contributing](#contributing)
+* [API](#api)
+  * [`fetch`](#fetch)
+  * [`fetch.defaults`](#fetch-defaults)
+  * [`minipass-fetch` options](#minipass-fetch-options)
+  * [`make-fetch-happen` options](#extra-options)
+    * [`opts.cachePath`](#opts-cache-path)
+    * [`opts.cache`](#opts-cache)
+    * [`opts.proxy`](#opts-proxy)
+    * [`opts.noProxy`](#opts-no-proxy)
+    * [`opts.ca, opts.cert, opts.key`](#https-opts)
+    * [`opts.maxSockets`](#opts-max-sockets)
+    * [`opts.retry`](#opts-retry)
+    * [`opts.onRetry`](#opts-onretry)
+    * [`opts.integrity`](#opts-integrity)
+* [Message From Our Sponsors](#wow)
+
+### Example
+
+```javascript
+const fetch = require('make-fetch-happen').defaults({
+  cachePath: './my-cache' // path where cache will be written (and read)
+})
+
+fetch('https://registry.npmjs.org/make-fetch-happen').then(res => {
+  return res.json() // download the body as JSON
+}).then(body => {
+  console.log(`got ${body.name} from web`)
+  return fetch('https://registry.npmjs.org/make-fetch-happen', {
+    cache: 'no-cache' // forces a conditional request
+  })
+}).then(res => {
+  console.log(res.status) // 304! cache validated!
+  return res.json().then(body => {
+    console.log(`got ${body.name} from cache`)
+  })
+})
+```
+
+### Features
+
+* Builds around [`minipass-fetch`](https://npm.im/minipass-fetch) for the core [`fetch` API](https://fetch.spec.whatwg.org) implementation
+* Request pooling out of the box
+* Quite fast, really
+* Automatic HTTP-semantics-aware request retries
+* Cache-fallback automatic "offline mode"
+* Proxy support (http, https, socks, socks4, socks5)
+* Built-in request caching following full HTTP caching rules (`Cache-Control`, `ETag`, `304`s, cache fallback on error, etc).
+* Customize cache storage with any [Cache API](https://developer.mozilla.org/en-US/docs/Web/API/Cache)-compliant `Cache` instance. Cache to Redis!
+* Node.js Stream support
+* Transparent gzip and deflate support
+* [Subresource Integrity](https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity) support
+* Literally punches nazis
+* (PENDING) Range request caching and resuming
+
+### Contributing
+
+The make-fetch-happen team enthusiastically welcomes contributions and project participation! There's a bunch of things you can do if you want to contribute! The [Contributor Guide](https://github.com/npm/cli/blob/latest/CONTRIBUTING.md) outlines the process for community interaction and contribution. Please don't hesitate to jump in if you'd like to, or even ask us questions if something isn't clear.
+
+All participants and maintainers in this project are expected to follow the [npm Code of Conduct](https://www.npmjs.com/policies/conduct), and just generally be excellent to each other.
+
+Please refer to the [Changelog](CHANGELOG.md) for project history details, too.
+
+Happy hacking!
+
+### API
+
+#### <a name="fetch"></a> `> fetch(uriOrRequest, [opts]) -> Promise<Response>`
+
+This function implements most of the [`fetch` API](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch): given a `uri` string or a `Request` instance, it will fire off an http request and return a Promise containing the relevant response.
+
+If `opts` is provided, the [`minipass-fetch`-specific options](#minipass-fetch-options) will be passed to that library. There are also [additional options](#extra-options) specific to make-fetch-happen that add various features, such as HTTP caching, integrity verification, proxy support, and more.
+
+##### Example
+
+```javascript
+fetch('https://google.com').then(res => res.buffer())
+```
+
+#### <a name="fetch-defaults"></a> `> fetch.defaults([defaultUrl], [defaultOpts])`
+
+Returns a new `fetch` function that will call `make-fetch-happen` using `defaultUrl` and `defaultOpts` as default values to any calls.
+
+A defaulted `fetch` will also have a `.defaults()` method, so they can be chained.
+
+##### Example
+
+```javascript
+const fetch = require('make-fetch-happen').defaults({
+  cachePath: './my-local-cache'
+})
+
+fetch('https://registry.npmjs.org/make-fetch-happen') // will always use the cache
+```
+
+#### <a name="minipass-fetch-options"></a> `> minipass-fetch options`
+
+The following options for `minipass-fetch` are used as-is:
+
+* method
+* body
+* redirect
+* follow
+* timeout
+* compress
+* size
+
+These other options are modified or augmented by make-fetch-happen:
+
+* headers - Default `User-Agent` set to make-fetch happen. `Connection` is set to `keep-alive` or `close` automatically depending on `opts.agent`.
+* agent
+  * If agent is null, an http or https Agent will be automatically used. By default, these will be `http.globalAgent` and `https.globalAgent`.
+  * If [`opts.proxy`](#opts-proxy) is provided and `opts.agent` is null, the agent will be set to an appropriate proxy-handling agent.
+  * If `opts.agent` is an object, it will be used as the request-pooling agent argument for this request.
+  * If `opts.agent` is `false`, it will be passed as-is to the underlying request library. This causes a new Agent to be spawned for every request.
+
+For more details, see [the documentation for `minipass-fetch` itself](https://github.com/npm/minipass-fetch#options).
+
+#### <a name="extra-options"></a> `> make-fetch-happen options`
+
+make-fetch-happen augments the `minipass-fetch` API with additional features available through extra options. The following extra options are available:
+
+* [`opts.cachePath`](#opts-cache-path) - Cache target to read/write
+* [`opts.cache`](#opts-cache) - `fetch` cache mode. Controls cache *behavior*.
+* [`opts.proxy`](#opts-proxy) - Proxy agent
+* [`opts.noProxy`](#opts-no-proxy) - Domain segments to disable proxying for.
+* [`opts.ca, opts.cert, opts.key, opts.strictSSL`](#https-opts)
+* [`opts.localAddress`](#opts-local-address)
+* [`opts.maxSockets`](#opts-max-sockets)
+* [`opts.retry`](#opts-retry) - Request retry settings
+* [`opts.onRetry`](#opts-onretry) - a function called whenever a retry is attempted
+* [`opts.integrity`](#opts-integrity) - [Subresource Integrity](https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity) metadata.
+
+#### <a name="opts-cache-path"></a> `> opts.cachePath`
+
+A string `Path` to be used as the cache root for [`cacache`](https://npm.im/cacache).
+
+**NOTE**: Requests will not be cached unless their response bodies are consumed. You will need to use one of the `res.json()`, `res.buffer()`, etc methods on the response, or drain the `res.body` stream, in order for it to be written.
+
+The default cache manager also adds the following headers to cached responses:
+
+* `X-Local-Cache`: Path to the cache the content was found in
+* `X-Local-Cache-Key`: Unique cache entry key for this response
+* `X-Local-Cache-Mode`: Either `stream` or `buffer` to indicate how the response was read from cacache
+* `X-Local-Cache-Hash`: Specific integrity hash for the cached entry
+* `X-Local-Cache-Status`: One of `miss`, `hit`, `stale`, `revalidated`, `updated`, or `skip` to signal how the response was created
+* `X-Local-Cache-Time`: UTCString of the cache insertion time for the entry
+
+Using [`cacache`](https://npm.im/cacache), a call like this may be used to
+manually fetch the cached entry:
+
+```javascript
+const h = response.headers
+cacache.get(h.get('x-local-cache'), h.get('x-local-cache-key'))
+
+// grab content only, directly:
+cacache.get.byDigest(h.get('x-local-cache'), h.get('x-local-cache-hash'))
+```
+
+##### Example
+
+```javascript
+fetch('https://registry.npmjs.org/make-fetch-happen', {
+  cachePath: './my-local-cache'
+}) // -> 200-level response will be written to disk
+```
+
+A possible (minimal) implementation for `MyCustomRedisCache`:
+
+```javascript
+const bluebird = require('bluebird')
+const redis = require("redis")
+bluebird.promisifyAll(redis.RedisClient.prototype)
+class MyCustomRedisCache {
+  constructor (opts) {
+    this.redis = redis.createClient(opts)
+  }
+  match (req) {
+    return this.redis.getAsync(req.url).then(res => {
+      if (res) {
+        const parsed = JSON.parse(res)
+        return new fetch.Response(parsed.body, {
+          url: req.url,
+          headers: parsed.headers,
+          status: 200
+        })
+      }
+    })
+  }
+  put (req, res) {
+    return res.buffer().then(body => {
+      return this.redis.setAsync(req.url, JSON.stringify({
+        body: body,
+        headers: res.headers.raw()
+      }))
+    }).then(() => {
+      // return the response itself
+      return res
+    })
+  }
+  'delete' (req) {
+    return this.redis.unlinkAsync(req.url)
+  }
+}
+```
+
+#### <a name="opts-cache"></a> `> opts.cache`
+
+This option follows the standard `fetch` API cache option. This option will do nothing if [`opts.cachePath`](#opts-cache-path) is null. The following values are accepted (as strings):
+
+* `default` - Fetch will inspect the HTTP cache on the way to the network. If there is a fresh response it will be used. If there is a stale response a conditional request will be created, and a normal request otherwise. It then updates the HTTP cache with the response. If the revalidation request fails (for example, on a 500 or if you're offline), the stale response will be returned.
+* `no-store` - Fetch behaves as if there is no HTTP cache at all.
+* `reload` - Fetch behaves as if there is no HTTP cache on the way to the network. Ergo, it creates a normal request and updates the HTTP cache with the response.
+* `no-cache` - Fetch creates a conditional request if there is a response in the HTTP cache and a normal request otherwise. It then updates the HTTP cache with the response.
+* `force-cache` - Fetch uses any response in the HTTP cache matching the request, not paying attention to staleness. If there was no response, it creates a normal request and updates the HTTP cache with the response.
+* `only-if-cached` - Fetch uses any response in the HTTP cache matching the request, not paying attention to staleness. If there was no response, it returns a network error. (Can only be used when request’s mode is "same-origin". Any cached redirects will be followed assuming request’s redirect mode is "follow" and the redirects do not violate request’s mode.)
+
+(Note: option descriptions are taken from https://fetch.spec.whatwg.org/#http-network-or-cache-fetch)
+
+##### Example
+
+```javascript
+const fetch = require('make-fetch-happen').defaults({
+  cachePath: './my-cache'
+})
+
+// Will error with ENOTCACHED if we haven't already cached this url
+fetch('https://registry.npmjs.org/make-fetch-happen', {
+  cache: 'only-if-cached'
+})
+
+// Will refresh any local content and cache the new response
+fetch('https://registry.npmjs.org/make-fetch-happen', {
+  cache: 'reload'
+})
+
+// Will use any local data, even if stale. Otherwise, will hit network.
+fetch('https://registry.npmjs.org/make-fetch-happen', {
+  cache: 'force-cache'
+})
+```
+
+#### <a name="opts-proxy"></a> `> opts.proxy`
+
+A string or `new url.URL()`-d URI to proxy through. Different Proxy handlers will be
+used depending on the proxy's protocol.
+
+Additionally, `process.env.HTTP_PROXY`, `process.env.HTTPS_PROXY`, and
+`process.env.PROXY` are used if present and no `opts.proxy` value is provided.
+
+(Pending) `process.env.NO_PROXY` may also be configured to skip proxying requests for all, or specific domains.
+
+##### Example
+
+```javascript
+fetch('https://registry.npmjs.org/make-fetch-happen', {
+  proxy: 'https://corporate.yourcompany.proxy:4445'
+})
+
+fetch('https://registry.npmjs.org/make-fetch-happen', {
+  proxy: {
+    protocol: 'https:',
+    hostname: 'corporate.yourcompany.proxy',
+    port: 4445
+  }
+})
+```
+
+#### <a name="opts-no-proxy"></a> `> opts.noProxy`
+
+If present, should be a comma-separated string or an array of domain extensions
+that a proxy should _not_ be used for.
+
+This option may also be provided through `process.env.NO_PROXY`.
+
+#### <a name="https-opts"></a> `> opts.ca, opts.cert, opts.key, opts.strictSSL`
+
+These values are passed in directly to the HTTPS agent and will be used for both
+proxied and unproxied outgoing HTTPS requests. They mostly correspond to the
+same options the `https` module accepts, which will be themselves passed to
+`tls.connect()`. `opts.strictSSL` corresponds to `rejectUnauthorized`.
+
+#### <a name="opts-local-address"></a> `> opts.localAddress`
+
+Passed directly to `http` and `https` request calls. Determines the local
+address to bind to.
+
+#### <a name="opts-max-sockets"></a> `> opts.maxSockets`
+
+Default: 15
+
+Maximum number of active concurrent sockets to use for the underlying
+Http/Https/Proxy agents. This setting applies once per spawned agent.
+
+15 is probably a _pretty good value_ for most use-cases, and balances speed
+with, uh, not knocking out people's routers. 🤓
+
+#### <a name="opts-retry"></a> `> opts.retry`
+
+An object that can be used to tune request retry settings. Retries will only be attempted on the following conditions:
+
+* Request method is NOT `POST` AND
+* Request status is one of: `408`, `420`, `429`, or any status in the 500-range. OR
+* Request errored with `ECONNRESET`, `ECONNREFUSED`, `EADDRINUSE`, `ETIMEDOUT`, or the `fetch` error `request-timeout`.
+
+The following are worth noting as explicitly not retried:
+
+* `getaddrinfo ENOTFOUND` and will be assumed to be either an unreachable domain or the user will be assumed offline. If a response is cached, it will be returned immediately.
+
+If `opts.retry` is `false`, it is equivalent to `{retries: 0}`
+
+If `opts.retry` is a number, it is equivalent to `{retries: num}`
+
+The following retry options are available if you want more control over it:
+
+* retries
+* factor
+* minTimeout
+* maxTimeout
+* randomize
+
+For details on what each of these do, refer to the [`retry`](https://npm.im/retry) documentation.
+
+##### Example
+
+```javascript
+fetch('https://flaky.site.com', {
+  retry: {
+    retries: 10,
+    randomize: true
+  }
+})
+
+fetch('http://reliable.site.com', {
+  retry: false
+})
+
+fetch('http://one-more.site.com', {
+  retry: 3
+})
+```
+
+#### <a name="opts-onretry"></a> `> opts.onRetry`
+
+A function called whenever a retry is attempted.
+
+##### Example
+
+```javascript
+fetch('https://flaky.site.com', {
+  onRetry() {
+    console.log('we will retry!')
+  }
+})
+```
+
+#### <a name="opts-integrity"></a> `> opts.integrity`
+
+Matches the response body against the given [Subresource Integrity](https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity) metadata. If verification fails, the request will fail with an `EINTEGRITY` error.
+
+`integrity` may either be a string or an [`ssri`](https://npm.im/ssri) `Integrity`-like.
+
+##### Example
+
+```javascript
+fetch('https://registry.npmjs.org/make-fetch-happen/-/make-fetch-happen-1.0.0.tgz', {
+  integrity: 'sha1-o47j7zAYnedYFn1dF/fR9OV3z8Q='
+}) // -> ok
+
+fetch('https://malicious-registry.org/make-fetch-happen/-/make-fetch-happen-1.0.0.tgz', {
+  integrity: 'sha1-o47j7zAYnedYFn1dF/fR9OV3z8Q='
+}) // Error: EINTEGRITY
+```
+
+### <a name="wow"></a> Message From Our Sponsors
+
+![](stop.gif)
+
+![](happening.gif)
diff --git a/server/node_modules/make-fetch-happen/lib/agent.js b/server/node_modules/make-fetch-happen/lib/agent.js
new file mode 100644
index 0000000..3675dd8
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/agent.js
@@ -0,0 +1,194 @@
+'use strict'
+const LRU = require('lru-cache')
+const url = require('url')
+const isLambda = require('is-lambda')
+
+const AGENT_CACHE = new LRU({ max: 50 })
+const HttpAgent = require('agentkeepalive')
+const HttpsAgent = HttpAgent.HttpsAgent
+
+module.exports = getAgent
+
+const getAgentTimeout = timeout =>
+  typeof timeout !== 'number' || !timeout ? 0 : timeout + 1
+
+const getMaxSockets = maxSockets => maxSockets || 15
+
+function getAgent (uri, opts) {
+  const parsedUri = new url.URL(typeof uri === 'string' ? uri : uri.url)
+  const isHttps = parsedUri.protocol === 'https:'
+  const pxuri = getProxyUri(parsedUri.href, opts)
+
+  // If opts.timeout is zero, set the agentTimeout to zero as well. A timeout
+  // of zero disables the timeout behavior (OS limits still apply). Else, if
+  // opts.timeout is a non-zero value, set it to timeout + 1, to ensure that
+  // the node-fetch-npm timeout will always fire first, giving us more
+  // consistent errors.
+  const agentTimeout = getAgentTimeout(opts.timeout)
+  const agentMaxSockets = getMaxSockets(opts.maxSockets)
+
+  const key = [
+    `https:${isHttps}`,
+    pxuri
+      ? `proxy:${pxuri.protocol}//${pxuri.host}:${pxuri.port}`
+      : '>no-proxy<',
+    `local-address:${opts.localAddress || '>no-local-address<'}`,
+    `strict-ssl:${isHttps ? opts.rejectUnauthorized : '>no-strict-ssl<'}`,
+    `ca:${(isHttps && opts.ca) || '>no-ca<'}`,
+    `cert:${(isHttps && opts.cert) || '>no-cert<'}`,
+    `key:${(isHttps && opts.key) || '>no-key<'}`,
+    `timeout:${agentTimeout}`,
+    `maxSockets:${agentMaxSockets}`,
+  ].join(':')
+
+  if (opts.agent != null) { // `agent: false` has special behavior!
+    return opts.agent
+  }
+
+  // keep alive in AWS lambda makes no sense
+  const lambdaAgent = !isLambda ? null
+    : isHttps ? require('https').globalAgent
+    : require('http').globalAgent
+
+  if (isLambda && !pxuri)
+    return lambdaAgent
+
+  if (AGENT_CACHE.peek(key))
+    return AGENT_CACHE.get(key)
+
+  if (pxuri) {
+    const pxopts = isLambda ? {
+      ...opts,
+      agent: lambdaAgent,
+    } : opts
+    const proxy = getProxy(pxuri, pxopts, isHttps)
+    AGENT_CACHE.set(key, proxy)
+    return proxy
+  }
+
+  const agent = isHttps ? new HttpsAgent({
+    maxSockets: agentMaxSockets,
+    ca: opts.ca,
+    cert: opts.cert,
+    key: opts.key,
+    localAddress: opts.localAddress,
+    rejectUnauthorized: opts.rejectUnauthorized,
+    timeout: agentTimeout,
+  }) : new HttpAgent({
+    maxSockets: agentMaxSockets,
+    localAddress: opts.localAddress,
+    timeout: agentTimeout,
+  })
+  AGENT_CACHE.set(key, agent)
+  return agent
+}
+
+function checkNoProxy (uri, opts) {
+  const host = new url.URL(uri).hostname.split('.').reverse()
+  let noproxy = (opts.noProxy || getProcessEnv('no_proxy'))
+  if (typeof noproxy === 'string')
+    noproxy = noproxy.split(/\s*,\s*/g)
+
+  return noproxy && noproxy.some(no => {
+    const noParts = no.split('.').filter(x => x).reverse()
+    if (!noParts.length)
+      return false
+    for (let i = 0; i < noParts.length; i++) {
+      if (host[i] !== noParts[i])
+        return false
+    }
+    return true
+  })
+}
+
+module.exports.getProcessEnv = getProcessEnv
+
+function getProcessEnv (env) {
+  if (!env)
+    return
+
+  let value
+
+  if (Array.isArray(env)) {
+    for (const e of env) {
+      value = process.env[e] ||
+        process.env[e.toUpperCase()] ||
+        process.env[e.toLowerCase()]
+      if (typeof value !== 'undefined')
+        break
+    }
+  }
+
+  if (typeof env === 'string') {
+    value = process.env[env] ||
+      process.env[env.toUpperCase()] ||
+      process.env[env.toLowerCase()]
+  }
+
+  return value
+}
+
+module.exports.getProxyUri = getProxyUri
+function getProxyUri (uri, opts) {
+  const protocol = new url.URL(uri).protocol
+
+  const proxy = opts.proxy ||
+    (
+      protocol === 'https:' &&
+      getProcessEnv('https_proxy')
+    ) ||
+    (
+      protocol === 'http:' &&
+      getProcessEnv(['https_proxy', 'http_proxy', 'proxy'])
+    )
+  if (!proxy)
+    return null
+
+  const parsedProxy = (typeof proxy === 'string') ? new url.URL(proxy) : proxy
+
+  return !checkNoProxy(uri, opts) && parsedProxy
+}
+
+const getAuth = u =>
+  u.username && u.password ? decodeURIComponent(`${u.username}:${u.password}`)
+  : u.username ? decodeURIComponent(u.username)
+  : null
+
+const getPath = u => u.pathname + u.search + u.hash
+
+const HttpProxyAgent = require('http-proxy-agent')
+const HttpsProxyAgent = require('https-proxy-agent')
+const SocksProxyAgent = require('socks-proxy-agent')
+module.exports.getProxy = getProxy
+function getProxy (proxyUrl, opts, isHttps) {
+  const popts = {
+    host: proxyUrl.hostname,
+    port: proxyUrl.port,
+    protocol: proxyUrl.protocol,
+    path: getPath(proxyUrl),
+    auth: getAuth(proxyUrl),
+    ca: opts.ca,
+    cert: opts.cert,
+    key: opts.key,
+    timeout: getAgentTimeout(opts.timeout),
+    localAddress: opts.localAddress,
+    maxSockets: getMaxSockets(opts.maxSockets),
+    rejectUnauthorized: opts.rejectUnauthorized,
+  }
+
+  if (proxyUrl.protocol === 'http:' || proxyUrl.protocol === 'https:') {
+    if (!isHttps)
+      return new HttpProxyAgent(popts)
+    else
+      return new HttpsProxyAgent(popts)
+  } else if (proxyUrl.protocol.startsWith('socks'))
+    return new SocksProxyAgent(popts)
+  else {
+    throw Object.assign(
+      new Error(`unsupported proxy protocol: '${proxyUrl.protocol}'`),
+      {
+        url: proxyUrl.href,
+      }
+    )
+  }
+}
diff --git a/server/node_modules/make-fetch-happen/lib/cache/entry.js b/server/node_modules/make-fetch-happen/lib/cache/entry.js
new file mode 100644
index 0000000..a2acea1
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/cache/entry.js
@@ -0,0 +1,460 @@
+const { Request, Response } = require('minipass-fetch')
+const Minipass = require('minipass')
+const MinipassCollect = require('minipass-collect')
+const MinipassFlush = require('minipass-flush')
+const MinipassPipeline = require('minipass-pipeline')
+const cacache = require('cacache')
+const url = require('url')
+
+const CachePolicy = require('./policy.js')
+const cacheKey = require('./key.js')
+const remote = require('../remote.js')
+
+const hasOwnProperty = (obj, prop) => Object.prototype.hasOwnProperty.call(obj, prop)
+
+// maximum amount of data we will buffer into memory
+// if we'll exceed this, we switch to streaming
+const MAX_MEM_SIZE = 5 * 1024 * 1024 // 5MB
+
+// allow list for request headers that will be written to the cache index
+// note: we will also store any request headers
+// that are named in a response's vary header
+const KEEP_REQUEST_HEADERS = [
+  'accept-charset',
+  'accept-encoding',
+  'accept-language',
+  'accept',
+  'cache-control',
+]
+
+// allow list for response headers that will be written to the cache index
+// note: we must not store the real response's age header, or when we load
+// a cache policy based on the metadata it will think the cached response
+// is always stale
+const KEEP_RESPONSE_HEADERS = [
+  'cache-control',
+  'content-encoding',
+  'content-language',
+  'content-type',
+  'date',
+  'etag',
+  'expires',
+  'last-modified',
+  'location',
+  'pragma',
+  'vary',
+]
+
+// return an object containing all metadata to be written to the index
+const getMetadata = (request, response, options) => {
+  const metadata = {
+    time: Date.now(),
+    url: request.url,
+    reqHeaders: {},
+    resHeaders: {},
+  }
+
+  // only save the status if it's not a 200 or 304
+  if (response.status !== 200 && response.status !== 304)
+    metadata.status = response.status
+
+  for (const name of KEEP_REQUEST_HEADERS) {
+    if (request.headers.has(name))
+      metadata.reqHeaders[name] = request.headers.get(name)
+  }
+
+  // if the request's host header differs from the host in the url
+  // we need to keep it, otherwise it's just noise and we ignore it
+  const host = request.headers.get('host')
+  const parsedUrl = new url.URL(request.url)
+  if (host && parsedUrl.host !== host)
+    metadata.reqHeaders.host = host
+
+  // if the response has a vary header, make sure
+  // we store the relevant request headers too
+  if (response.headers.has('vary')) {
+    const vary = response.headers.get('vary')
+    // a vary of "*" means every header causes a different response.
+    // in that scenario, we do not include any additional headers
+    // as the freshness check will always fail anyway and we don't
+    // want to bloat the cache indexes
+    if (vary !== '*') {
+      // copy any other request headers that will vary the response
+      const varyHeaders = vary.trim().toLowerCase().split(/\s*,\s*/)
+      for (const name of varyHeaders) {
+        // explicitly ignore accept-encoding here
+        if (name !== 'accept-encoding' && request.headers.has(name))
+          metadata.reqHeaders[name] = request.headers.get(name)
+      }
+    }
+  }
+
+  for (const name of KEEP_RESPONSE_HEADERS) {
+    if (response.headers.has(name))
+      metadata.resHeaders[name] = response.headers.get(name)
+  }
+
+  // we only store accept-encoding and content-encoding if the user
+  // has disabled automatic compression and decompression in minipass-fetch
+  // since if it's enabled (the default) then the content will have
+  // already been decompressed making the header a lie
+  if (options.compress === false) {
+    metadata.reqHeaders['accept-encoding'] = request.headers.get('accept-encoding')
+    metadata.resHeaders['content-encoding'] = response.headers.get('content-encoding')
+  }
+
+  return metadata
+}
+
+// symbols used to hide objects that may be lazily evaluated in a getter
+const _request = Symbol('request')
+const _response = Symbol('response')
+const _policy = Symbol('policy')
+
+class CacheEntry {
+  constructor ({ entry, request, response, options }) {
+    if (entry) {
+      this.key = entry.key
+      this.entry = entry
+      // previous versions of this module didn't write an explicit timestamp in
+      // the metadata, so fall back to the entry's timestamp. we can't use the
+      // entry timestamp to determine staleness because cacache will update it
+      // when it verifies its data
+      this.entry.metadata.time = this.entry.metadata.time || this.entry.time
+    } else
+      this.key = cacheKey(request)
+
+    this.options = options
+
+    // these properties are behind getters that lazily evaluate
+    this[_request] = request
+    this[_response] = response
+    this[_policy] = null
+  }
+
+  // returns a CacheEntry instance that satisfies the given request
+  // or undefined if no existing entry satisfies
+  static async find (request, options) {
+    try {
+      // compacts the index and returns an array of unique entries
+      var matches = await cacache.index.compact(options.cachePath, cacheKey(request), (A, B) => {
+        const entryA = new CacheEntry({ entry: A, options })
+        const entryB = new CacheEntry({ entry: B, options })
+        return entryA.policy.satisfies(entryB.request)
+      }, {
+        validateEntry: (entry) => {
+          // if an integrity is null, it needs to have a status specified
+          if (entry.integrity === null)
+            return !!(entry.metadata && entry.metadata.status)
+
+          return true
+        },
+      })
+    } catch (err) {
+      // if the compact request fails, ignore the error and return
+      return
+    }
+
+    // a cache mode of 'reload' means to behave as though we have no cache
+    // on the way to the network. return undefined to allow cacheFetch to
+    // create a brand new request no matter what.
+    if (options.cache === 'reload')
+      return
+
+    // find the specific entry that satisfies the request
+    let match
+    for (const entry of matches) {
+      const _entry = new CacheEntry({
+        entry,
+        options,
+      })
+
+      if (_entry.policy.satisfies(request)) {
+        match = _entry
+        break
+      }
+    }
+
+    return match
+  }
+
+  // if the user made a PUT/POST/PATCH then we invalidate our
+  // cache for the same url by deleting the index entirely
+  static async invalidate (request, options) {
+    const key = cacheKey(request)
+    try {
+      await cacache.rm.entry(options.cachePath, key, { removeFully: true })
+    } catch (err) {
+      // ignore errors
+    }
+  }
+
+  get request () {
+    if (!this[_request]) {
+      this[_request] = new Request(this.entry.metadata.url, {
+        method: 'GET',
+        headers: this.entry.metadata.reqHeaders,
+      })
+    }
+
+    return this[_request]
+  }
+
+  get response () {
+    if (!this[_response]) {
+      this[_response] = new Response(null, {
+        url: this.entry.metadata.url,
+        counter: this.options.counter,
+        status: this.entry.metadata.status || 200,
+        headers: {
+          ...this.entry.metadata.resHeaders,
+          'content-length': this.entry.size,
+        },
+      })
+    }
+
+    return this[_response]
+  }
+
+  get policy () {
+    if (!this[_policy]) {
+      this[_policy] = new CachePolicy({
+        entry: this.entry,
+        request: this.request,
+        response: this.response,
+        options: this.options,
+      })
+    }
+
+    return this[_policy]
+  }
+
+  // wraps the response in a pipeline that stores the data
+  // in the cache while the user consumes it
+  async store (status) {
+    // if we got a status other than 200, 301, or 308,
+    // or the CachePolicy forbid storage, append the
+    // cache status header and return it untouched
+    if (this.request.method !== 'GET' || ![200, 301, 308].includes(this.response.status) || !this.policy.storable()) {
+      this.response.headers.set('x-local-cache-status', 'skip')
+      return this.response
+    }
+
+    const size = this.response.headers.get('content-length')
+    const fitsInMemory = !!size && Number(size) < MAX_MEM_SIZE
+    const shouldBuffer = this.options.memoize !== false && fitsInMemory
+    const cacheOpts = {
+      algorithms: this.options.algorithms,
+      metadata: getMetadata(this.request, this.response, this.options),
+      size,
+      memoize: fitsInMemory && this.options.memoize,
+    }
+
+    let body = null
+    // we only set a body if the status is a 200, redirects are
+    // stored as metadata only
+    if (this.response.status === 200) {
+      let cacheWriteResolve, cacheWriteReject
+      const cacheWritePromise = new Promise((resolve, reject) => {
+        cacheWriteResolve = resolve
+        cacheWriteReject = reject
+      })
+
+      body = new MinipassPipeline(new MinipassFlush({
+        flush () {
+          return cacheWritePromise
+        },
+      }))
+
+      let abortStream, onResume
+      if (shouldBuffer) {
+        // if the result fits in memory, use a collect stream to gather
+        // the response and write it to cacache while also passing it through
+        // to the user
+        onResume = () => {
+          const collector = new MinipassCollect.PassThrough()
+          abortStream = collector
+          collector.on('collect', (data) => {
+            // TODO if the cache write fails, log a warning but return the response anyway
+            cacache.put(this.options.cachePath, this.key, data, cacheOpts).then(cacheWriteResolve, cacheWriteReject)
+          })
+          body.unshift(collector)
+          body.unshift(this.response.body)
+        }
+      } else {
+        // if it does not fit in memory, create a tee stream and use
+        // that to pipe to both the cache and the user simultaneously
+        onResume = () => {
+          const tee = new Minipass()
+          const cacheStream = cacache.put.stream(this.options.cachePath, this.key, cacheOpts)
+          abortStream = cacheStream
+          tee.pipe(cacheStream)
+          // TODO if the cache write fails, log a warning but return the response anyway
+          cacheStream.promise().then(cacheWriteResolve, cacheWriteReject)
+          body.unshift(tee)
+          body.unshift(this.response.body)
+        }
+      }
+
+      body.once('resume', onResume)
+      body.once('end', () => body.removeListener('resume', onResume))
+      this.response.body.on('error', (err) => {
+        // the abortStream will either be a MinipassCollect if we buffer
+        // or a cacache write stream, either way be sure to listen for
+        // errors from the actual response and avoid writing data that we
+        // know to be invalid to the cache
+        abortStream.destroy(err)
+      })
+    } else
+      await cacache.index.insert(this.options.cachePath, this.key, null, cacheOpts)
+
+    // note: we do not set the x-local-cache-hash header because we do not know
+    // the hash value until after the write to the cache completes, which doesn't
+    // happen until after the response has been sent and it's too late to write
+    // the header anyway
+    this.response.headers.set('x-local-cache', encodeURIComponent(this.options.cachePath))
+    this.response.headers.set('x-local-cache-key', encodeURIComponent(this.key))
+    this.response.headers.set('x-local-cache-mode', shouldBuffer ? 'buffer' : 'stream')
+    this.response.headers.set('x-local-cache-status', status)
+    this.response.headers.set('x-local-cache-time', new Date().toISOString())
+    const newResponse = new Response(body, {
+      url: this.response.url,
+      status: this.response.status,
+      headers: this.response.headers,
+      counter: this.options.counter,
+    })
+    return newResponse
+  }
+
+  // use the cached data to create a response and return it
+  async respond (method, options, status) {
+    let response
+    const size = Number(this.response.headers.get('content-length'))
+    const fitsInMemory = !!size && size < MAX_MEM_SIZE
+    const shouldBuffer = this.options.memoize !== false && fitsInMemory
+    if (method === 'HEAD' || [301, 308].includes(this.response.status)) {
+      // if the request is a HEAD, or the response is a redirect,
+      // then the metadata in the entry already includes everything
+      // we need to build a response
+      response = this.response
+    } else {
+      // we're responding with a full cached response, so create a body
+      // that reads from cacache and attach it to a new Response
+      const body = new Minipass()
+      const removeOnResume = () => body.removeListener('resume', onResume)
+      let onResume
+      if (shouldBuffer) {
+        onResume = async () => {
+          removeOnResume()
+          try {
+            const content = await cacache.get.byDigest(this.options.cachePath, this.entry.integrity, { memoize: this.options.memoize })
+            body.end(content)
+          } catch (err) {
+            if (err.code === 'EINTEGRITY')
+              await cacache.rm.content(this.options.cachePath, this.entry.integrity, { memoize: this.options.memoize })
+            if (err.code === 'ENOENT' || err.code === 'EINTEGRITY')
+              await CacheEntry.invalidate(this.request, this.options)
+            body.emit('error', err)
+          }
+        }
+      } else {
+        onResume = () => {
+          const cacheStream = cacache.get.stream.byDigest(this.options.cachePath, this.entry.integrity, { memoize: this.options.memoize })
+          cacheStream.on('error', async (err) => {
+            cacheStream.pause()
+            if (err.code === 'EINTEGRITY')
+              await cacache.rm.content(this.options.cachePath, this.entry.integrity, { memoize: this.options.memoize })
+            if (err.code === 'ENOENT' || err.code === 'EINTEGRITY')
+              await CacheEntry.invalidate(this.request, this.options)
+            body.emit('error', err)
+            cacheStream.resume()
+          })
+          cacheStream.pipe(body)
+        }
+      }
+
+      body.once('resume', onResume)
+      body.once('end', removeOnResume)
+      response = new Response(body, {
+        url: this.entry.metadata.url,
+        counter: options.counter,
+        status: 200,
+        headers: {
+          ...this.policy.responseHeaders(),
+        },
+      })
+    }
+
+    response.headers.set('x-local-cache', encodeURIComponent(this.options.cachePath))
+    response.headers.set('x-local-cache-hash', encodeURIComponent(this.entry.integrity))
+    response.headers.set('x-local-cache-key', encodeURIComponent(this.key))
+    response.headers.set('x-local-cache-mode', shouldBuffer ? 'buffer' : 'stream')
+    response.headers.set('x-local-cache-status', status)
+    response.headers.set('x-local-cache-time', new Date(this.entry.metadata.time).toUTCString())
+    return response
+  }
+
+  // use the provided request along with this cache entry to
+  // revalidate the stored response. returns a response, either
+  // from the cache or from the update
+  async revalidate (request, options) {
+    const revalidateRequest = new Request(request, {
+      headers: this.policy.revalidationHeaders(request),
+    })
+
+    try {
+      // NOTE: be sure to remove the headers property from the
+      // user supplied options, since we have already defined
+      // them on the new request object. if they're still in the
+      // options then those will overwrite the ones from the policy
+      var response = await remote(revalidateRequest, {
+        ...options,
+        headers: undefined,
+      })
+    } catch (err) {
+      // if the network fetch fails, return the stale
+      // cached response unless it has a cache-control
+      // of 'must-revalidate'
+      if (!this.policy.mustRevalidate)
+        return this.respond(request.method, options, 'stale')
+
+      throw err
+    }
+
+    if (this.policy.revalidated(revalidateRequest, response)) {
+      // we got a 304, write a new index to the cache and respond from cache
+      const metadata = getMetadata(request, response, options)
+      // 304 responses do not include headers that are specific to the response data
+      // since they do not include a body, so we copy values for headers that were
+      // in the old cache entry to the new one, if the new metadata does not already
+      // include that header
+      for (const name of KEEP_RESPONSE_HEADERS) {
+        if (!hasOwnProperty(metadata.resHeaders, name) && hasOwnProperty(this.entry.metadata.resHeaders, name))
+          metadata.resHeaders[name] = this.entry.metadata.resHeaders[name]
+      }
+
+      try {
+        await cacache.index.insert(options.cachePath, this.key, this.entry.integrity, {
+          size: this.entry.size,
+          metadata,
+        })
+      } catch (err) {
+        // if updating the cache index fails, we ignore it and
+        // respond anyway
+      }
+      return this.respond(request.method, options, 'revalidated')
+    }
+
+    // if we got a modified response, create a new entry based on it
+    const newEntry = new CacheEntry({
+      request,
+      response,
+      options,
+    })
+
+    // respond with the new entry while writing it to the cache
+    return newEntry.store('updated')
+  }
+}
+
+module.exports = CacheEntry
diff --git a/server/node_modules/make-fetch-happen/lib/cache/errors.js b/server/node_modules/make-fetch-happen/lib/cache/errors.js
new file mode 100644
index 0000000..31e97c4
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/cache/errors.js
@@ -0,0 +1,10 @@
+class NotCachedError extends Error {
+  constructor (url) {
+    super(`request to ${url} failed: cache mode is 'only-if-cached' but no cached response is available.`)
+    this.code = 'ENOTCACHED'
+  }
+}
+
+module.exports = {
+  NotCachedError,
+}
diff --git a/server/node_modules/make-fetch-happen/lib/cache/index.js b/server/node_modules/make-fetch-happen/lib/cache/index.js
new file mode 100644
index 0000000..cca93d9
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/cache/index.js
@@ -0,0 +1,45 @@
+const { NotCachedError } = require('./errors.js')
+const CacheEntry = require('./entry.js')
+const remote = require('../remote.js')
+
+// do whatever is necessary to get a Response and return it
+const cacheFetch = async (request, options) => {
+  // try to find a cached entry that satisfies this request
+  const entry = await CacheEntry.find(request, options)
+  if (!entry) {
+    // no cached result, if the cache mode is 'only-if-cached' that's a failure
+    if (options.cache === 'only-if-cached')
+      throw new NotCachedError(request.url)
+
+    // otherwise, we make a request, store it and return it
+    const response = await remote(request, options)
+    const entry = new CacheEntry({ request, response, options })
+    return entry.store('miss')
+  }
+
+  // we have a cached response that satisfies this request, however if the cache
+  // mode is 'no-cache' then we send the revalidation request no matter what
+  if (options.cache === 'no-cache')
+    return entry.revalidate(request, options)
+
+  // if the cached entry is not stale, or if the cache mode is 'force-cache' or
+  // 'only-if-cached' we can respond with the cached entry. set the status
+  // based on the result of needsRevalidation and respond
+  const _needsRevalidation = entry.policy.needsRevalidation(request)
+  if (options.cache === 'force-cache' ||
+      options.cache === 'only-if-cached' ||
+      !_needsRevalidation)
+    return entry.respond(request.method, options, _needsRevalidation ? 'stale' : 'hit')
+
+  // if we got here, the cache entry is stale so revalidate it
+  return entry.revalidate(request, options)
+}
+
+cacheFetch.invalidate = async (request, options) => {
+  if (!options.cachePath)
+    return
+
+  return CacheEntry.invalidate(request, options)
+}
+
+module.exports = cacheFetch
diff --git a/server/node_modules/make-fetch-happen/lib/cache/key.js b/server/node_modules/make-fetch-happen/lib/cache/key.js
new file mode 100644
index 0000000..f7684d5
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/cache/key.js
@@ -0,0 +1,17 @@
+const { URL, format } = require('url')
+
+// options passed to url.format() when generating a key
+const formatOptions = {
+  auth: false,
+  fragment: false,
+  search: true,
+  unicode: false,
+}
+
+// returns a string to be used as the cache key for the Request
+const cacheKey = (request) => {
+  const parsed = new URL(request.url)
+  return `make-fetch-happen:request-cache:${format(parsed, formatOptions)}`
+}
+
+module.exports = cacheKey
diff --git a/server/node_modules/make-fetch-happen/lib/cache/policy.js b/server/node_modules/make-fetch-happen/lib/cache/policy.js
new file mode 100644
index 0000000..e0959f6
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/cache/policy.js
@@ -0,0 +1,161 @@
+const CacheSemantics = require('http-cache-semantics')
+const Negotiator = require('negotiator')
+const ssri = require('ssri')
+
+// HACK: negotiator lazy loads several of its own modules
+// as a micro optimization. we need to be sure that they're
+// in memory as soon as possible at startup so that we do
+// not try to lazy load them after the directory has been
+// retired during a self update of the npm CLI, we do this
+// by calling all of the methods that trigger a lazy load
+// on a fake instance.
+const preloadNegotiator = new Negotiator({ headers: {} })
+preloadNegotiator.charsets()
+preloadNegotiator.encodings()
+preloadNegotiator.languages()
+preloadNegotiator.mediaTypes()
+
+// options passed to http-cache-semantics constructor
+const policyOptions = {
+  shared: false,
+  ignoreCargoCult: true,
+}
+
+// a fake empty response, used when only testing the
+// request for storability
+const emptyResponse = { status: 200, headers: {} }
+
+// returns a plain object representation of the Request
+const requestObject = (request) => {
+  const _obj = {
+    method: request.method,
+    url: request.url,
+    headers: {},
+  }
+
+  request.headers.forEach((value, key) => {
+    _obj.headers[key] = value
+  })
+
+  return _obj
+}
+
+// returns a plain object representation of the Response
+const responseObject = (response) => {
+  const _obj = {
+    status: response.status,
+    headers: {},
+  }
+
+  response.headers.forEach((value, key) => {
+    _obj.headers[key] = value
+  })
+
+  return _obj
+}
+
+class CachePolicy {
+  constructor ({ entry, request, response, options }) {
+    this.entry = entry
+    this.request = requestObject(request)
+    this.response = responseObject(response)
+    this.options = options
+    this.policy = new CacheSemantics(this.request, this.response, policyOptions)
+
+    if (this.entry) {
+      // if we have an entry, copy the timestamp to the _responseTime
+      // this is necessary because the CacheSemantics constructor forces
+      // the value to Date.now() which means a policy created from a
+      // cache entry is likely to always identify itself as stale
+      this.policy._responseTime = this.entry.metadata.time
+    }
+  }
+
+  // static method to quickly determine if a request alone is storable
+  static storable (request, options) {
+    // no cachePath means no caching
+    if (!options.cachePath)
+      return false
+
+    // user explicitly asked not to cache
+    if (options.cache === 'no-store')
+      return false
+
+    // we only cache GET and HEAD requests
+    if (!['GET', 'HEAD'].includes(request.method))
+      return false
+
+    // otherwise, let http-cache-semantics make the decision
+    // based on the request's headers
+    const policy = new CacheSemantics(requestObject(request), emptyResponse, policyOptions)
+    return policy.storable()
+  }
+
+  // returns true if the policy satisfies the request
+  satisfies (request) {
+    const _req = requestObject(request)
+    if (this.request.headers.host !== _req.headers.host)
+      return false
+
+    const negotiatorA = new Negotiator(this.request)
+    const negotiatorB = new Negotiator(_req)
+
+    if (JSON.stringify(negotiatorA.mediaTypes()) !== JSON.stringify(negotiatorB.mediaTypes()))
+      return false
+
+    if (JSON.stringify(negotiatorA.languages()) !== JSON.stringify(negotiatorB.languages()))
+      return false
+
+    if (JSON.stringify(negotiatorA.encodings()) !== JSON.stringify(negotiatorB.encodings()))
+      return false
+
+    if (this.options.integrity)
+      return ssri.parse(this.options.integrity).match(this.entry.integrity)
+
+    return true
+  }
+
+  // returns true if the request and response allow caching
+  storable () {
+    return this.policy.storable()
+  }
+
+  // NOTE: this is a hack to avoid parsing the cache-control
+  // header ourselves, it returns true if the response's
+  // cache-control contains must-revalidate
+  get mustRevalidate () {
+    return !!this.policy._rescc['must-revalidate']
+  }
+
+  // returns true if the cached response requires revalidation
+  // for the given request
+  needsRevalidation (request) {
+    const _req = requestObject(request)
+    // force method to GET because we only cache GETs
+    // but can serve a HEAD from a cached GET
+    _req.method = 'GET'
+    return !this.policy.satisfiesWithoutRevalidation(_req)
+  }
+
+  responseHeaders () {
+    return this.policy.responseHeaders()
+  }
+
+  // returns a new object containing the appropriate headers
+  // to send a revalidation request
+  revalidationHeaders (request) {
+    const _req = requestObject(request)
+    return this.policy.revalidationHeaders(_req)
+  }
+
+  // returns true if the request/response was revalidated
+  // successfully. returns false if a new response was received
+  revalidated (request, response) {
+    const _req = requestObject(request)
+    const _res = responseObject(response)
+    const policy = this.policy.revalidatedPolicy(_req, _res)
+    return !policy.modified
+  }
+}
+
+module.exports = CachePolicy
diff --git a/server/node_modules/make-fetch-happen/lib/fetch.js b/server/node_modules/make-fetch-happen/lib/fetch.js
new file mode 100644
index 0000000..dfded79
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/fetch.js
@@ -0,0 +1,100 @@
+'use strict'
+
+const { FetchError, Request, isRedirect } = require('minipass-fetch')
+const url = require('url')
+
+const CachePolicy = require('./cache/policy.js')
+const cache = require('./cache/index.js')
+const remote = require('./remote.js')
+
+// given a Request, a Response and user options
+// return true if the response is a redirect that
+// can be followed. we throw errors that will result
+// in the fetch being rejected if the redirect is
+// possible but invalid for some reason
+const canFollowRedirect = (request, response, options) => {
+  if (!isRedirect(response.status))
+    return false
+
+  if (options.redirect === 'manual')
+    return false
+
+  if (options.redirect === 'error')
+    throw new FetchError(`redirect mode is set to error: ${request.url}`, 'no-redirect', { code: 'ENOREDIRECT' })
+
+  if (!response.headers.has('location'))
+    throw new FetchError(`redirect location header missing for: ${request.url}`, 'no-location', { code: 'EINVALIDREDIRECT' })
+
+  if (request.counter >= request.follow)
+    throw new FetchError(`maximum redirect reached at: ${request.url}`, 'max-redirect', { code: 'EMAXREDIRECT' })
+
+  return true
+}
+
+// given a Request, a Response, and the user's options return an object
+// with a new Request and a new options object that will be used for
+// following the redirect
+const getRedirect = (request, response, options) => {
+  const _opts = { ...options }
+  const location = response.headers.get('location')
+  const redirectUrl = new url.URL(location, /^https?:/.test(location) ? undefined : request.url)
+  // Comment below is used under the following license:
+  // Copyright (c) 2010-2012 Mikeal Rogers
+  // Licensed under the Apache License, Version 2.0 (the "License");
+  // you may not use this file except in compliance with the License.
+  // You may obtain a copy of the License at
+  // http://www.apache.org/licenses/LICENSE-2.0
+  // Unless required by applicable law or agreed to in writing,
+  // software distributed under the License is distributed on an "AS
+  // IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+  // express or implied. See the License for the specific language
+  // governing permissions and limitations under the License.
+
+  // Remove authorization if changing hostnames (but not if just
+  // changing ports or protocols).  This matches the behavior of request:
+  // https://github.com/request/request/blob/b12a6245/lib/redirect.js#L134-L138
+  if (new url.URL(request.url).hostname !== redirectUrl.hostname)
+    request.headers.delete('authorization')
+
+  // for POST request with 301/302 response, or any request with 303 response,
+  // use GET when following redirect
+  if (response.status === 303 || (request.method === 'POST' && [301, 302].includes(response.status))) {
+    _opts.method = 'GET'
+    _opts.body = null
+    request.headers.delete('content-length')
+  }
+
+  _opts.headers = {}
+  request.headers.forEach((value, key) => {
+    _opts.headers[key] = value
+  })
+
+  _opts.counter = ++request.counter
+  const redirectReq = new Request(url.format(redirectUrl), _opts)
+  return {
+    request: redirectReq,
+    options: _opts,
+  }
+}
+
+const fetch = async (request, options) => {
+  const response = CachePolicy.storable(request, options)
+    ? await cache(request, options)
+    : await remote(request, options)
+
+  // if the request wasn't a GET or HEAD, and the response
+  // status is between 200 and 399 inclusive, invalidate the
+  // request url
+  if (!['GET', 'HEAD'].includes(request.method) &&
+      response.status >= 200 &&
+      response.status <= 399)
+    await cache.invalidate(request, options)
+
+  if (!canFollowRedirect(request, response, options))
+    return response
+
+  const redirect = getRedirect(request, response, options)
+  return fetch(redirect.request, redirect.options)
+}
+
+module.exports = fetch
diff --git a/server/node_modules/make-fetch-happen/lib/index.js b/server/node_modules/make-fetch-happen/lib/index.js
new file mode 100644
index 0000000..6028bc0
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/index.js
@@ -0,0 +1,40 @@
+const { FetchError, Headers, Request, Response } = require('minipass-fetch')
+
+const configureOptions = require('./options.js')
+const fetch = require('./fetch.js')
+
+const makeFetchHappen = (url, opts) => {
+  const options = configureOptions(opts)
+
+  const request = new Request(url, options)
+  return fetch(request, options)
+}
+
+makeFetchHappen.defaults = (defaultUrl, defaultOptions = {}) => {
+  if (typeof defaultUrl === 'object') {
+    defaultOptions = defaultUrl
+    defaultUrl = null
+  }
+
+  const defaultedFetch = (url, options = {}) => {
+    const finalUrl = url || defaultUrl
+    const finalOptions = {
+      ...defaultOptions,
+      ...options,
+      headers: {
+        ...defaultOptions.headers,
+        ...options.headers,
+      },
+    }
+    return makeFetchHappen(finalUrl, finalOptions)
+  }
+
+  defaultedFetch.defaults = makeFetchHappen.defaults
+  return defaultedFetch
+}
+
+module.exports = makeFetchHappen
+module.exports.FetchError = FetchError
+module.exports.Headers = Headers
+module.exports.Request = Request
+module.exports.Response = Response
diff --git a/server/node_modules/make-fetch-happen/lib/options.js b/server/node_modules/make-fetch-happen/lib/options.js
new file mode 100644
index 0000000..f6138e6
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/options.js
@@ -0,0 +1,44 @@
+const conditionalHeaders = [
+  'if-modified-since',
+  'if-none-match',
+  'if-unmodified-since',
+  'if-match',
+  'if-range',
+]
+
+const configureOptions = (opts) => {
+  const {strictSSL, ...options} = { ...opts }
+  options.method = options.method ? options.method.toUpperCase() : 'GET'
+  options.rejectUnauthorized = strictSSL !== false
+
+  if (!options.retry)
+    options.retry = { retries: 0 }
+  else if (typeof options.retry === 'string') {
+    const retries = parseInt(options.retry, 10)
+    if (isFinite(retries))
+      options.retry = { retries }
+    else
+      options.retry = { retries: 0 }
+  } else if (typeof options.retry === 'number')
+    options.retry = { retries: options.retry }
+  else
+    options.retry = { retries: 0, ...options.retry }
+
+  options.cache = options.cache || 'default'
+  if (options.cache === 'default') {
+    const hasConditionalHeader = Object.keys(options.headers || {}).some((name) => {
+      return conditionalHeaders.includes(name.toLowerCase())
+    })
+    if (hasConditionalHeader)
+      options.cache = 'no-store'
+  }
+
+  // cacheManager is deprecated, but if it's set and
+  // cachePath is not we should copy it to the new field
+  if (options.cacheManager && !options.cachePath)
+    options.cachePath = options.cacheManager
+
+  return options
+}
+
+module.exports = configureOptions
diff --git a/server/node_modules/make-fetch-happen/lib/remote.js b/server/node_modules/make-fetch-happen/lib/remote.js
new file mode 100644
index 0000000..7e4ed24
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/lib/remote.js
@@ -0,0 +1,102 @@
+const Minipass = require('minipass')
+const MinipassPipeline = require('minipass-pipeline')
+const fetch = require('minipass-fetch')
+const promiseRetry = require('promise-retry')
+const ssri = require('ssri')
+
+const getAgent = require('./agent.js')
+const pkg = require('../package.json')
+
+const USER_AGENT = `${pkg.name}/${pkg.version} (+https://npm.im/${pkg.name})`
+
+const RETRY_ERRORS = [
+  'ECONNRESET', // remote socket closed on us
+  'ECONNREFUSED', // remote host refused to open connection
+  'EADDRINUSE', // failed to bind to a local port (proxy?)
+  'ETIMEDOUT', // someone in the transaction is WAY TOO SLOW
+  'ERR_SOCKET_TIMEOUT', // same as above, but this one comes from agentkeepalive
+  // Known codes we do NOT retry on:
+  // ENOTFOUND (getaddrinfo failure. Either bad hostname, or offline)
+]
+
+const RETRY_TYPES = [
+  'request-timeout',
+]
+
+// make a request directly to the remote source,
+// retrying certain classes of errors as well as
+// following redirects (through the cache if necessary)
+// and verifying response integrity
+const remoteFetch = (request, options) => {
+  const agent = getAgent(request.url, options)
+  if (!request.headers.has('connection'))
+    request.headers.set('connection', agent ? 'keep-alive' : 'close')
+
+  if (!request.headers.has('user-agent'))
+    request.headers.set('user-agent', USER_AGENT)
+
+  // keep our own options since we're overriding the agent
+  // and the redirect mode
+  const _opts = {
+    ...options,
+    agent,
+    redirect: 'manual',
+  }
+
+  return promiseRetry(async (retryHandler, attemptNum) => {
+    const req = new fetch.Request(request, _opts)
+    try {
+      let res = await fetch(req, _opts)
+      if (_opts.integrity && res.status === 200) {
+        // we got a 200 response and the user has specified an expected
+        // integrity value, so wrap the response in an ssri stream to verify it
+        const integrityStream = ssri.integrityStream({ integrity: _opts.integrity })
+        res = new fetch.Response(new MinipassPipeline(res.body, integrityStream), res)
+      }
+
+      res.headers.set('x-fetch-attempts', attemptNum)
+
+      // do not retry POST requests, or requests with a streaming body
+      // do retry requests with a 408, 420, 429 or 500+ status in the response
+      const isStream = Minipass.isStream(req.body)
+      const isRetriable = req.method !== 'POST' &&
+          !isStream &&
+          ([408, 420, 429].includes(res.status) || res.status >= 500)
+
+      if (isRetriable) {
+        if (typeof options.onRetry === 'function')
+          options.onRetry(res)
+
+        return retryHandler(res)
+      }
+
+      return res
+    } catch (err) {
+      const code = (err.code === 'EPROMISERETRY')
+        ? err.retried.code
+        : err.code
+
+      // err.retried will be the thing that was thrown from above
+      // if it's a response, we just got a bad status code and we
+      // can re-throw to allow the retry
+      const isRetryError = err.retried instanceof fetch.Response ||
+        (RETRY_ERRORS.includes(code) && RETRY_TYPES.includes(err.type))
+
+      if (req.method === 'POST' || isRetryError)
+        throw err
+
+      if (typeof options.onRetry === 'function')
+        options.onRetry(err)
+
+      return retryHandler(err)
+    }
+  }, options.retry).catch((err) => {
+    // don't reject for http errors, just return them
+    if (err.status >= 400 && err.type !== 'system')
+      return err
+
+    throw err
+  })
+}
+
+module.exports = remoteFetch
diff --git a/server/node_modules/make-fetch-happen/package.json b/server/node_modules/make-fetch-happen/package.json
new file mode 100644
index 0000000..dae7b37
--- /dev/null
+++ b/server/node_modules/make-fetch-happen/package.json
@@ -0,0 +1,76 @@
+{
+  "name": "make-fetch-happen",
+  "version": "9.1.0",
+  "description": "Opinionated, caching, retrying fetch client",
+  "main": "lib/index.js",
+  "files": [
+    "lib"
+  ],
+  "scripts": {
+    "preversion": "npm t",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push --follow-tags",
+    "test": "tap",
+    "posttest": "npm run lint",
+    "eslint": "eslint",
+    "lint": "npm run eslint -- lib test",
+    "lintfix": "npm run lint -- --fix"
+  },
+  "repository": "https://github.com/npm/make-fetch-happen",
+  "keywords": [
+    "http",
+    "request",
+    "fetch",
+    "mean girls",
+    "caching",
+    "cache",
+    "subresource integrity"
+  ],
+  "author": {
+    "name": "Kat Marchán",
+    "email": "kzm@zkat.tech",
+    "twitter": "maybekatz"
+  },
+  "license": "ISC",
+  "dependencies": {
+    "agentkeepalive": "^4.1.3",
+    "cacache": "^15.2.0",
+    "http-cache-semantics": "^4.1.0",
+    "http-proxy-agent": "^4.0.1",
+    "https-proxy-agent": "^5.0.0",
+    "is-lambda": "^1.0.1",
+    "lru-cache": "^6.0.0",
+    "minipass": "^3.1.3",
+    "minipass-collect": "^1.0.2",
+    "minipass-fetch": "^1.3.2",
+    "minipass-flush": "^1.0.5",
+    "minipass-pipeline": "^1.2.4",
+    "negotiator": "^0.6.2",
+    "promise-retry": "^2.0.1",
+    "socks-proxy-agent": "^6.0.0",
+    "ssri": "^8.0.0"
+  },
+  "devDependencies": {
+    "eslint": "^7.26.0",
+    "eslint-plugin-import": "^2.23.2",
+    "eslint-plugin-node": "^11.1.0",
+    "eslint-plugin-promise": "^5.1.0",
+    "eslint-plugin-standard": "^5.0.0",
+    "mkdirp": "^1.0.4",
+    "nock": "^13.0.11",
+    "npmlog": "^5.0.0",
+    "require-inject": "^1.4.2",
+    "rimraf": "^3.0.2",
+    "safe-buffer": "^5.2.1",
+    "standard-version": "^9.3.0",
+    "tap": "^15.0.9"
+  },
+  "engines": {
+    "node": ">= 10"
+  },
+  "tap": {
+    "color": 1,
+    "files": "test/*.js",
+    "check-coverage": true
+  }
+}
diff --git a/server/node_modules/math-intrinsics/.eslintrc b/server/node_modules/math-intrinsics/.eslintrc
new file mode 100644
index 0000000..d90a1bc
--- /dev/null
+++ b/server/node_modules/math-intrinsics/.eslintrc
@@ -0,0 +1,16 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"eqeqeq": ["error", "allow-null"],
+		"id-length": "off",
+		"new-cap": ["error", {
+			"capIsNewExceptions": [
+				"RequireObjectCoercible",
+				"ToObject",
+			],
+		}],
+	},
+}
diff --git a/server/node_modules/math-intrinsics/.github/FUNDING.yml b/server/node_modules/math-intrinsics/.github/FUNDING.yml
new file mode 100644
index 0000000..868f4ff
--- /dev/null
+++ b/server/node_modules/math-intrinsics/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/math-intrinsics
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with a single custom sponsorship URL
diff --git a/server/node_modules/math-intrinsics/CHANGELOG.md b/server/node_modules/math-intrinsics/CHANGELOG.md
new file mode 100644
index 0000000..9cf48f5
--- /dev/null
+++ b/server/node_modules/math-intrinsics/CHANGELOG.md
@@ -0,0 +1,24 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.1.0](https://github.com/es-shims/math-intrinsics/compare/v1.0.0...v1.1.0) - 2024-12-18
+
+### Commits
+
+- [New] add `round` [`7cfb044`](https://github.com/es-shims/math-intrinsics/commit/7cfb04460c0fbdf1ca101eecbac3f59d11994130)
+- [Tests] add attw [`e96be8f`](https://github.com/es-shims/math-intrinsics/commit/e96be8fbf58449eafe976446a0470e6ea561ad8d)
+- [Dev Deps] update `@types/tape` [`30d0023`](https://github.com/es-shims/math-intrinsics/commit/30d00234ce8a3fa0094a61cd55d6686eb91e36ec)
+
+## v1.0.0 - 2024-12-11
+
+### Commits
+
+- Initial implementation, tests, readme, types [`b898caa`](https://github.com/es-shims/math-intrinsics/commit/b898caae94e9994a94a42b8740f7bbcfd0a868fe)
+- Initial commit [`02745b0`](https://github.com/es-shims/math-intrinsics/commit/02745b03a62255af8a332771987b55d127538d9c)
+- [New] add `constants/maxArrayLength`, `mod` [`b978178`](https://github.com/es-shims/math-intrinsics/commit/b978178a57685bd23ed1c7efe2137f3784f5fcc5)
+- npm init [`a39fc57`](https://github.com/es-shims/math-intrinsics/commit/a39fc57e5639a645d0bd52a0dc56202480223be2)
+- Only apps should have lockfiles [`9451580`](https://github.com/es-shims/math-intrinsics/commit/94515800fb34db4f3cc7e99290042d45609ac7bd)
diff --git a/server/node_modules/math-intrinsics/LICENSE b/server/node_modules/math-intrinsics/LICENSE
new file mode 100644
index 0000000..34995e7
--- /dev/null
+++ b/server/node_modules/math-intrinsics/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 ECMAScript Shims
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/math-intrinsics/README.md b/server/node_modules/math-intrinsics/README.md
new file mode 100644
index 0000000..4a66dcf
--- /dev/null
+++ b/server/node_modules/math-intrinsics/README.md
@@ -0,0 +1,50 @@
+# math-intrinsics <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+ES Math-related intrinsics and helpers, robustly cached.
+
+ - `abs`
+ - `floor`
+ - `isFinite`
+ - `isInteger`
+ - `isNaN`
+ - `isNegativeZero`
+ - `max`
+ - `min`
+ - `mod`
+ - `pow`
+ - `round`
+ - `sign`
+ - `constants/maxArrayLength`
+ - `constants/maxSafeInteger`
+ - `constants/maxValue`
+
+
+## Tests
+Simply clone the repo, `npm install`, and run `npm test`
+
+## Security
+
+Please email [@ljharb](https://github.com/ljharb) or see https://tidelift.com/security if you have a potential security vulnerability to report.
+
+[package-url]: https://npmjs.org/package/math-intrinsics
+[npm-version-svg]: https://versionbadg.es/es-shims/math-intrinsics.svg
+[deps-svg]: https://david-dm.org/es-shims/math-intrinsics.svg
+[deps-url]: https://david-dm.org/es-shims/math-intrinsics
+[dev-deps-svg]: https://david-dm.org/es-shims/math-intrinsics/dev-status.svg
+[dev-deps-url]: https://david-dm.org/es-shims/math-intrinsics#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/math-intrinsics.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/math-intrinsics.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/es-object.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=math-intrinsics
+[codecov-image]: https://codecov.io/gh/es-shims/math-intrinsics/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/es-shims/math-intrinsics/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/es-shims/math-intrinsics
+[actions-url]: https://github.com/es-shims/math-intrinsics/actions
diff --git a/server/node_modules/math-intrinsics/abs.d.ts b/server/node_modules/math-intrinsics/abs.d.ts
new file mode 100644
index 0000000..14ad9c6
--- /dev/null
+++ b/server/node_modules/math-intrinsics/abs.d.ts
@@ -0,0 +1 @@
+export = Math.abs;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/abs.js b/server/node_modules/math-intrinsics/abs.js
new file mode 100644
index 0000000..a751424
--- /dev/null
+++ b/server/node_modules/math-intrinsics/abs.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./abs')} */
+module.exports = Math.abs;
diff --git a/server/node_modules/math-intrinsics/constants/maxArrayLength.d.ts b/server/node_modules/math-intrinsics/constants/maxArrayLength.d.ts
new file mode 100644
index 0000000..b92d46b
--- /dev/null
+++ b/server/node_modules/math-intrinsics/constants/maxArrayLength.d.ts
@@ -0,0 +1,3 @@
+declare const MAX_ARRAY_LENGTH: 4294967295;
+
+export = MAX_ARRAY_LENGTH;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/constants/maxArrayLength.js b/server/node_modules/math-intrinsics/constants/maxArrayLength.js
new file mode 100644
index 0000000..cfc6aff
--- /dev/null
+++ b/server/node_modules/math-intrinsics/constants/maxArrayLength.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./maxArrayLength')} */
+module.exports = 4294967295; // Math.pow(2, 32) - 1;
diff --git a/server/node_modules/math-intrinsics/constants/maxSafeInteger.d.ts b/server/node_modules/math-intrinsics/constants/maxSafeInteger.d.ts
new file mode 100644
index 0000000..fee3f62
--- /dev/null
+++ b/server/node_modules/math-intrinsics/constants/maxSafeInteger.d.ts
@@ -0,0 +1,3 @@
+declare const MAX_SAFE_INTEGER: 9007199254740991;
+
+export = MAX_SAFE_INTEGER;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/constants/maxSafeInteger.js b/server/node_modules/math-intrinsics/constants/maxSafeInteger.js
new file mode 100644
index 0000000..b568ad3
--- /dev/null
+++ b/server/node_modules/math-intrinsics/constants/maxSafeInteger.js
@@ -0,0 +1,5 @@
+'use strict';
+
+/** @type {import('./maxSafeInteger')} */
+// eslint-disable-next-line no-extra-parens
+module.exports = /** @type {import('./maxSafeInteger')} */ (Number.MAX_SAFE_INTEGER) || 9007199254740991; // Math.pow(2, 53) - 1;
diff --git a/server/node_modules/math-intrinsics/constants/maxValue.d.ts b/server/node_modules/math-intrinsics/constants/maxValue.d.ts
new file mode 100644
index 0000000..292cb82
--- /dev/null
+++ b/server/node_modules/math-intrinsics/constants/maxValue.d.ts
@@ -0,0 +1,3 @@
+declare const MAX_VALUE: 1.7976931348623157e+308;
+
+export = MAX_VALUE;
diff --git a/server/node_modules/math-intrinsics/constants/maxValue.js b/server/node_modules/math-intrinsics/constants/maxValue.js
new file mode 100644
index 0000000..a2202dc
--- /dev/null
+++ b/server/node_modules/math-intrinsics/constants/maxValue.js
@@ -0,0 +1,5 @@
+'use strict';
+
+/** @type {import('./maxValue')}  */
+// eslint-disable-next-line no-extra-parens
+module.exports = /** @type {import('./maxValue')}  */ (Number.MAX_VALUE) || 1.7976931348623157e+308;
diff --git a/server/node_modules/math-intrinsics/floor.d.ts b/server/node_modules/math-intrinsics/floor.d.ts
new file mode 100644
index 0000000..9265236
--- /dev/null
+++ b/server/node_modules/math-intrinsics/floor.d.ts
@@ -0,0 +1 @@
+export = Math.floor;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/floor.js b/server/node_modules/math-intrinsics/floor.js
new file mode 100644
index 0000000..ab0e5d7
--- /dev/null
+++ b/server/node_modules/math-intrinsics/floor.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./floor')} */
+module.exports = Math.floor;
diff --git a/server/node_modules/math-intrinsics/isFinite.d.ts b/server/node_modules/math-intrinsics/isFinite.d.ts
new file mode 100644
index 0000000..6daae33
--- /dev/null
+++ b/server/node_modules/math-intrinsics/isFinite.d.ts
@@ -0,0 +1,3 @@
+declare function isFinite(x: unknown): x is number | bigint;
+
+export = isFinite;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/isFinite.js b/server/node_modules/math-intrinsics/isFinite.js
new file mode 100644
index 0000000..b201a5a
--- /dev/null
+++ b/server/node_modules/math-intrinsics/isFinite.js
@@ -0,0 +1,12 @@
+'use strict';
+
+var $isNaN = require('./isNaN');
+
+/** @type {import('./isFinite')} */
+module.exports = function isFinite(x) {
+	return (typeof x === 'number' || typeof x === 'bigint')
+        && !$isNaN(x)
+        && x !== Infinity
+        && x !== -Infinity;
+};
+
diff --git a/server/node_modules/math-intrinsics/isInteger.d.ts b/server/node_modules/math-intrinsics/isInteger.d.ts
new file mode 100644
index 0000000..13935a8
--- /dev/null
+++ b/server/node_modules/math-intrinsics/isInteger.d.ts
@@ -0,0 +1,3 @@
+declare function isInteger(argument: unknown): argument is number;
+
+export = isInteger;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/isInteger.js b/server/node_modules/math-intrinsics/isInteger.js
new file mode 100644
index 0000000..4b1b9a5
--- /dev/null
+++ b/server/node_modules/math-intrinsics/isInteger.js
@@ -0,0 +1,16 @@
+'use strict';
+
+var $abs = require('./abs');
+var $floor = require('./floor');
+
+var $isNaN = require('./isNaN');
+var $isFinite = require('./isFinite');
+
+/** @type {import('./isInteger')} */
+module.exports = function isInteger(argument) {
+	if (typeof argument !== 'number' || $isNaN(argument) || !$isFinite(argument)) {
+		return false;
+	}
+	var absValue = $abs(argument);
+	return $floor(absValue) === absValue;
+};
diff --git a/server/node_modules/math-intrinsics/isNaN.d.ts b/server/node_modules/math-intrinsics/isNaN.d.ts
new file mode 100644
index 0000000..c1d4c55
--- /dev/null
+++ b/server/node_modules/math-intrinsics/isNaN.d.ts
@@ -0,0 +1 @@
+export = Number.isNaN;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/isNaN.js b/server/node_modules/math-intrinsics/isNaN.js
new file mode 100644
index 0000000..e36475c
--- /dev/null
+++ b/server/node_modules/math-intrinsics/isNaN.js
@@ -0,0 +1,6 @@
+'use strict';
+
+/** @type {import('./isNaN')} */
+module.exports = Number.isNaN || function isNaN(a) {
+	return a !== a;
+};
diff --git a/server/node_modules/math-intrinsics/isNegativeZero.d.ts b/server/node_modules/math-intrinsics/isNegativeZero.d.ts
new file mode 100644
index 0000000..7ad8819
--- /dev/null
+++ b/server/node_modules/math-intrinsics/isNegativeZero.d.ts
@@ -0,0 +1,3 @@
+declare function isNegativeZero(x: unknown): boolean;
+
+export = isNegativeZero;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/isNegativeZero.js b/server/node_modules/math-intrinsics/isNegativeZero.js
new file mode 100644
index 0000000..b69adcc
--- /dev/null
+++ b/server/node_modules/math-intrinsics/isNegativeZero.js
@@ -0,0 +1,6 @@
+'use strict';
+
+/** @type {import('./isNegativeZero')} */
+module.exports = function isNegativeZero(x) {
+	return x === 0 && 1 / x === 1 / -0;
+};
diff --git a/server/node_modules/math-intrinsics/max.d.ts b/server/node_modules/math-intrinsics/max.d.ts
new file mode 100644
index 0000000..ad6f43e
--- /dev/null
+++ b/server/node_modules/math-intrinsics/max.d.ts
@@ -0,0 +1 @@
+export = Math.max;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/max.js b/server/node_modules/math-intrinsics/max.js
new file mode 100644
index 0000000..edb55df
--- /dev/null
+++ b/server/node_modules/math-intrinsics/max.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./max')} */
+module.exports = Math.max;
diff --git a/server/node_modules/math-intrinsics/min.d.ts b/server/node_modules/math-intrinsics/min.d.ts
new file mode 100644
index 0000000..fd90f2d
--- /dev/null
+++ b/server/node_modules/math-intrinsics/min.d.ts
@@ -0,0 +1 @@
+export = Math.min;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/min.js b/server/node_modules/math-intrinsics/min.js
new file mode 100644
index 0000000..5a4a7c7
--- /dev/null
+++ b/server/node_modules/math-intrinsics/min.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./min')} */
+module.exports = Math.min;
diff --git a/server/node_modules/math-intrinsics/mod.d.ts b/server/node_modules/math-intrinsics/mod.d.ts
new file mode 100644
index 0000000..549dbd4
--- /dev/null
+++ b/server/node_modules/math-intrinsics/mod.d.ts
@@ -0,0 +1,3 @@
+declare function mod(number: number, modulo: number): number;
+
+export = mod;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/mod.js b/server/node_modules/math-intrinsics/mod.js
new file mode 100644
index 0000000..4a98362
--- /dev/null
+++ b/server/node_modules/math-intrinsics/mod.js
@@ -0,0 +1,9 @@
+'use strict';
+
+var $floor = require('./floor');
+
+/** @type {import('./mod')} */
+module.exports = function mod(number, modulo) {
+	var remain = number % modulo;
+	return $floor(remain >= 0 ? remain : remain + modulo);
+};
diff --git a/server/node_modules/math-intrinsics/package.json b/server/node_modules/math-intrinsics/package.json
new file mode 100644
index 0000000..0676273
--- /dev/null
+++ b/server/node_modules/math-intrinsics/package.json
@@ -0,0 +1,86 @@
+{
+	"name": "math-intrinsics",
+	"version": "1.1.0",
+	"description": "ES Math-related intrinsics and helpers, robustly cached.",
+	"main": false,
+	"exports": {
+		"./abs": "./abs.js",
+		"./floor": "./floor.js",
+		"./isFinite": "./isFinite.js",
+		"./isInteger": "./isInteger.js",
+		"./isNaN": "./isNaN.js",
+		"./isNegativeZero": "./isNegativeZero.js",
+		"./max": "./max.js",
+		"./min": "./min.js",
+		"./mod": "./mod.js",
+		"./pow": "./pow.js",
+		"./sign": "./sign.js",
+		"./round": "./round.js",
+		"./constants/maxArrayLength": "./constants/maxArrayLength.js",
+		"./constants/maxSafeInteger": "./constants/maxSafeInteger.js",
+		"./constants/maxValue": "./constants/maxValue.js",
+		"./package.json": "./package.json"
+	},
+	"sideEffects": false,
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"pretest": "npm run lint",
+		"test": "npm run tests-only",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"posttest": "npx npm@'>= 10.2' audit --production",
+		"prelint": "evalmd README.md && eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git' | grep -v dist/)",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc && attw -P",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/es-shims/math-intrinsics.git"
+	},
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/es-shims/math-intrinsics/issues"
+	},
+	"homepage": "https://github.com/es-shims/math-intrinsics#readme",
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.1",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.2",
+		"@types/for-each": "^0.3.3",
+		"@types/object-inspect": "^1.13.0",
+		"@types/tape": "^5.8.0",
+		"auto-changelog": "^2.5.0",
+		"eclint": "^2.8.1",
+		"es-value-fixtures": "^1.5.0",
+		"eslint": "^8.8.0",
+		"evalmd": "^0.0.19",
+		"for-each": "^0.3.3",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"object-inspect": "^1.13.3",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/math-intrinsics/pow.d.ts b/server/node_modules/math-intrinsics/pow.d.ts
new file mode 100644
index 0000000..5873c44
--- /dev/null
+++ b/server/node_modules/math-intrinsics/pow.d.ts
@@ -0,0 +1 @@
+export = Math.pow;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/pow.js b/server/node_modules/math-intrinsics/pow.js
new file mode 100644
index 0000000..c0a4103
--- /dev/null
+++ b/server/node_modules/math-intrinsics/pow.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./pow')} */
+module.exports = Math.pow;
diff --git a/server/node_modules/math-intrinsics/round.d.ts b/server/node_modules/math-intrinsics/round.d.ts
new file mode 100644
index 0000000..da1fde3
--- /dev/null
+++ b/server/node_modules/math-intrinsics/round.d.ts
@@ -0,0 +1 @@
+export = Math.round;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/round.js b/server/node_modules/math-intrinsics/round.js
new file mode 100644
index 0000000..b792156
--- /dev/null
+++ b/server/node_modules/math-intrinsics/round.js
@@ -0,0 +1,4 @@
+'use strict';
+
+/** @type {import('./round')} */
+module.exports = Math.round;
diff --git a/server/node_modules/math-intrinsics/sign.d.ts b/server/node_modules/math-intrinsics/sign.d.ts
new file mode 100644
index 0000000..c49ceca
--- /dev/null
+++ b/server/node_modules/math-intrinsics/sign.d.ts
@@ -0,0 +1,3 @@
+declare function sign(x: number): number;
+
+export = sign;
\ No newline at end of file
diff --git a/server/node_modules/math-intrinsics/sign.js b/server/node_modules/math-intrinsics/sign.js
new file mode 100644
index 0000000..9e5173c
--- /dev/null
+++ b/server/node_modules/math-intrinsics/sign.js
@@ -0,0 +1,11 @@
+'use strict';
+
+var $isNaN = require('./isNaN');
+
+/** @type {import('./sign')} */
+module.exports = function sign(number) {
+	if ($isNaN(number) || number === 0) {
+		return number;
+	}
+	return number < 0 ? -1 : +1;
+};
diff --git a/server/node_modules/math-intrinsics/test/index.js b/server/node_modules/math-intrinsics/test/index.js
new file mode 100644
index 0000000..0f90a5d
--- /dev/null
+++ b/server/node_modules/math-intrinsics/test/index.js
@@ -0,0 +1,192 @@
+'use strict';
+
+var test = require('tape');
+var v = require('es-value-fixtures');
+var forEach = require('for-each');
+var inspect = require('object-inspect');
+
+var abs = require('../abs');
+var floor = require('../floor');
+var isFinite = require('../isFinite');
+var isInteger = require('../isInteger');
+var isNaN = require('../isNaN');
+var isNegativeZero = require('../isNegativeZero');
+var max = require('../max');
+var min = require('../min');
+var mod = require('../mod');
+var pow = require('../pow');
+var round = require('../round');
+var sign = require('../sign');
+
+var maxArrayLength = require('../constants/maxArrayLength');
+var maxSafeInteger = require('../constants/maxSafeInteger');
+var maxValue = require('../constants/maxValue');
+
+test('abs', function (t) {
+	t.equal(abs(-1), 1, 'abs(-1) === 1');
+	t.equal(abs(+1), 1, 'abs(+1) === 1');
+	t.equal(abs(+0), +0, 'abs(+0) === +0');
+	t.equal(abs(-0), +0, 'abs(-0) === +0');
+
+	t.end();
+});
+
+test('floor', function (t) {
+	t.equal(floor(-1.1), -2, 'floor(-1.1) === -2');
+	t.equal(floor(+1.1), 1, 'floor(+1.1) === 1');
+	t.equal(floor(+0), +0, 'floor(+0) === +0');
+	t.equal(floor(-0), -0, 'floor(-0) === -0');
+	t.equal(floor(-Infinity), -Infinity, 'floor(-Infinity) === -Infinity');
+	t.equal(floor(Number(Infinity)), Number(Infinity), 'floor(+Infinity) === +Infinity');
+	t.equal(floor(NaN), NaN, 'floor(NaN) === NaN');
+	t.equal(floor(0), +0, 'floor(0) === +0');
+	t.equal(floor(-0), -0, 'floor(-0) === -0');
+	t.equal(floor(1), 1, 'floor(1) === 1');
+	t.equal(floor(-1), -1, 'floor(-1) === -1');
+	t.equal(floor(1.1), 1, 'floor(1.1) === 1');
+	t.equal(floor(-1.1), -2, 'floor(-1.1) === -2');
+	t.equal(floor(maxValue), maxValue, 'floor(maxValue) === maxValue');
+	t.equal(floor(maxSafeInteger), maxSafeInteger, 'floor(maxSafeInteger) === maxSafeInteger');
+
+	t.end();
+});
+
+test('isFinite', function (t) {
+	t.equal(isFinite(0), true, 'isFinite(+0) === true');
+	t.equal(isFinite(-0), true, 'isFinite(-0) === true');
+	t.equal(isFinite(1), true, 'isFinite(1) === true');
+	t.equal(isFinite(Infinity), false, 'isFinite(Infinity) === false');
+	t.equal(isFinite(-Infinity), false, 'isFinite(-Infinity) === false');
+	t.equal(isFinite(NaN), false, 'isFinite(NaN) === false');
+
+	forEach(v.nonNumbers, function (nonNumber) {
+		t.equal(isFinite(nonNumber), false, 'isFinite(' + inspect(nonNumber) + ') === false');
+	});
+
+	t.end();
+});
+
+test('isInteger', function (t) {
+	forEach([].concat(
+		// @ts-expect-error TS sucks with concat
+		v.nonNumbers,
+		v.nonIntegerNumbers
+	), function (nonInteger) {
+		t.equal(isInteger(nonInteger), false, 'isInteger(' + inspect(nonInteger) + ') === false');
+	});
+
+	t.end();
+});
+
+test('isNaN', function (t) {
+	forEach([].concat(
+		// @ts-expect-error TS sucks with concat
+		v.nonNumbers,
+		v.infinities,
+		v.zeroes,
+		v.integerNumbers
+	), function (nonNaN) {
+		t.equal(isNaN(nonNaN), false, 'isNaN(' + inspect(nonNaN) + ') === false');
+	});
+
+	t.equal(isNaN(NaN), true, 'isNaN(NaN) === true');
+
+	t.end();
+});
+
+test('isNegativeZero', function (t) {
+	t.equal(isNegativeZero(-0), true, 'isNegativeZero(-0) === true');
+	t.equal(isNegativeZero(+0), false, 'isNegativeZero(+0) === false');
+	t.equal(isNegativeZero(1), false, 'isNegativeZero(1) === false');
+	t.equal(isNegativeZero(-1), false, 'isNegativeZero(-1) === false');
+	t.equal(isNegativeZero(NaN), false, 'isNegativeZero(NaN) === false');
+	t.equal(isNegativeZero(Infinity), false, 'isNegativeZero(Infinity) === false');
+	t.equal(isNegativeZero(-Infinity), false, 'isNegativeZero(-Infinity) === false');
+
+	forEach(v.nonNumbers, function (nonNumber) {
+		t.equal(isNegativeZero(nonNumber), false, 'isNegativeZero(' + inspect(nonNumber) + ') === false');
+	});
+
+	t.end();
+});
+
+test('max', function (t) {
+	t.equal(max(1, 2), 2, 'max(1, 2) === 2');
+	t.equal(max(1, 2, 3), 3, 'max(1, 2, 3) === 3');
+	t.equal(max(1, 2, 3, 4), 4, 'max(1, 2, 3, 4) === 4');
+	t.equal(max(1, 2, 3, 4, 5), 5, 'max(1, 2, 3, 4, 5) === 5');
+	t.equal(max(1, 2, 3, 4, 5, 6), 6, 'max(1, 2, 3, 4, 5, 6) === 6');
+	t.equal(max(1, 2, 3, 4, 5, 6, 7), 7, 'max(1, 2, 3, 4, 5, 6, 7) === 7');
+
+	t.end();
+});
+
+test('min', function (t) {
+	t.equal(min(1, 2), 1, 'min(1, 2) === 1');
+	t.equal(min(1, 2, 3), 1, 'min(1, 2, 3) === 1');
+	t.equal(min(1, 2, 3, 4), 1, 'min(1, 2, 3, 4) === 1');
+	t.equal(min(1, 2, 3, 4, 5), 1, 'min(1, 2, 3, 4, 5) === 1');
+	t.equal(min(1, 2, 3, 4, 5, 6), 1, 'min(1, 2, 3, 4, 5, 6) === 1');
+
+	t.end();
+});
+
+test('mod', function (t) {
+	t.equal(mod(1, 2), 1, 'mod(1, 2) === 1');
+	t.equal(mod(2, 2), 0, 'mod(2, 2) === 0');
+	t.equal(mod(3, 2), 1, 'mod(3, 2) === 1');
+	t.equal(mod(4, 2), 0, 'mod(4, 2) === 0');
+	t.equal(mod(5, 2), 1, 'mod(5, 2) === 1');
+	t.equal(mod(6, 2), 0, 'mod(6, 2) === 0');
+	t.equal(mod(7, 2), 1, 'mod(7, 2) === 1');
+	t.equal(mod(8, 2), 0, 'mod(8, 2) === 0');
+	t.equal(mod(9, 2), 1, 'mod(9, 2) === 1');
+	t.equal(mod(10, 2), 0, 'mod(10, 2) === 0');
+	t.equal(mod(11, 2), 1, 'mod(11, 2) === 1');
+
+	t.end();
+});
+
+test('pow', function (t) {
+	t.equal(pow(2, 2), 4, 'pow(2, 2) === 4');
+	t.equal(pow(2, 3), 8, 'pow(2, 3) === 8');
+	t.equal(pow(2, 4), 16, 'pow(2, 4) === 16');
+	t.equal(pow(2, 5), 32, 'pow(2, 5) === 32');
+	t.equal(pow(2, 6), 64, 'pow(2, 6) === 64');
+	t.equal(pow(2, 7), 128, 'pow(2, 7) === 128');
+	t.equal(pow(2, 8), 256, 'pow(2, 8) === 256');
+	t.equal(pow(2, 9), 512, 'pow(2, 9) === 512');
+	t.equal(pow(2, 10), 1024, 'pow(2, 10) === 1024');
+
+	t.end();
+});
+
+test('round', function (t) {
+	t.equal(round(1.1), 1, 'round(1.1) === 1');
+	t.equal(round(1.5), 2, 'round(1.5) === 2');
+	t.equal(round(1.9), 2, 'round(1.9) === 2');
+
+	t.end();
+});
+
+test('sign', function (t) {
+	t.equal(sign(-1), -1, 'sign(-1) === -1');
+	t.equal(sign(+1), +1, 'sign(+1) === +1');
+	t.equal(sign(+0), +0, 'sign(+0) === +0');
+	t.equal(sign(-0), -0, 'sign(-0) === -0');
+	t.equal(sign(NaN), NaN, 'sign(NaN) === NaN');
+	t.equal(sign(Infinity), +1, 'sign(Infinity) === +1');
+	t.equal(sign(-Infinity), -1, 'sign(-Infinity) === -1');
+	t.equal(sign(maxValue), +1, 'sign(maxValue) === +1');
+	t.equal(sign(maxSafeInteger), +1, 'sign(maxSafeInteger) === +1');
+
+	t.end();
+});
+
+test('constants', function (t) {
+	t.equal(typeof maxArrayLength, 'number', 'typeof maxArrayLength === "number"');
+	t.equal(typeof maxSafeInteger, 'number', 'typeof maxSafeInteger === "number"');
+	t.equal(typeof maxValue, 'number', 'typeof maxValue === "number"');
+
+	t.end();
+});
diff --git a/server/node_modules/math-intrinsics/tsconfig.json b/server/node_modules/math-intrinsics/tsconfig.json
new file mode 100644
index 0000000..b131000
--- /dev/null
+++ b/server/node_modules/math-intrinsics/tsconfig.json
@@ -0,0 +1,3 @@
+{
+	"extends": "@ljharb/tsconfig",
+}
diff --git a/server/node_modules/media-typer/HISTORY.md b/server/node_modules/media-typer/HISTORY.md
new file mode 100644
index 0000000..62c2003
--- /dev/null
+++ b/server/node_modules/media-typer/HISTORY.md
@@ -0,0 +1,22 @@
+0.3.0 / 2014-09-07
+==================
+
+  * Support Node.js 0.6
+  * Throw error when parameter format invalid on parse
+
+0.2.0 / 2014-06-18
+==================
+
+  * Add `typer.format()` to format media types
+
+0.1.0 / 2014-06-17
+==================
+
+  * Accept `req` as argument to `parse`
+  * Accept `res` as argument to `parse`
+  * Parse media type with extra LWS between type and first parameter
+
+0.0.0 / 2014-06-13
+==================
+
+  * Initial implementation
diff --git a/server/node_modules/media-typer/LICENSE b/server/node_modules/media-typer/LICENSE
new file mode 100644
index 0000000..b7dce6c
--- /dev/null
+++ b/server/node_modules/media-typer/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2014 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/media-typer/README.md b/server/node_modules/media-typer/README.md
new file mode 100644
index 0000000..d8df623
--- /dev/null
+++ b/server/node_modules/media-typer/README.md
@@ -0,0 +1,81 @@
+# media-typer
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Simple RFC 6838 media type parser
+
+## Installation
+
+```sh
+$ npm install media-typer
+```
+
+## API
+
+```js
+var typer = require('media-typer')
+```
+
+### typer.parse(string)
+
+```js
+var obj = typer.parse('image/svg+xml; charset=utf-8')
+```
+
+Parse a media type string. This will return an object with the following
+properties (examples are shown for the string `'image/svg+xml; charset=utf-8'`):
+
+ - `type`: The type of the media type (always lower case). Example: `'image'`
+
+ - `subtype`: The subtype of the media type (always lower case). Example: `'svg'`
+
+ - `suffix`: The suffix of the media type (always lower case). Example: `'xml'`
+
+ - `parameters`: An object of the parameters in the media type (name of parameter always lower case). Example: `{charset: 'utf-8'}`
+
+### typer.parse(req)
+
+```js
+var obj = typer.parse(req)
+```
+
+Parse the `content-type` header from the given `req`. Short-cut for
+`typer.parse(req.headers['content-type'])`.
+
+### typer.parse(res)
+
+```js
+var obj = typer.parse(res)
+```
+
+Parse the `content-type` header set on the given `res`. Short-cut for
+`typer.parse(res.getHeader('content-type'))`.
+
+### typer.format(obj)
+
+```js
+var obj = typer.format({type: 'image', subtype: 'svg', suffix: 'xml'})
+```
+
+Format an object into a media type string. This will return a string of the
+mime type for the given object. For the properties of the object, see the
+documentation for `typer.parse(string)`.
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/media-typer.svg?style=flat
+[npm-url]: https://npmjs.org/package/media-typer
+[node-version-image]: https://img.shields.io/badge/node.js-%3E%3D_0.6-brightgreen.svg?style=flat
+[node-version-url]: http://nodejs.org/download/
+[travis-image]: https://img.shields.io/travis/jshttp/media-typer.svg?style=flat
+[travis-url]: https://travis-ci.org/jshttp/media-typer
+[coveralls-image]: https://img.shields.io/coveralls/jshttp/media-typer.svg?style=flat
+[coveralls-url]: https://coveralls.io/r/jshttp/media-typer
+[downloads-image]: https://img.shields.io/npm/dm/media-typer.svg?style=flat
+[downloads-url]: https://npmjs.org/package/media-typer
diff --git a/server/node_modules/media-typer/index.js b/server/node_modules/media-typer/index.js
new file mode 100644
index 0000000..07f7295
--- /dev/null
+++ b/server/node_modules/media-typer/index.js
@@ -0,0 +1,270 @@
+/*!
+ * media-typer
+ * Copyright(c) 2014 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+/**
+ * RegExp to match *( ";" parameter ) in RFC 2616 sec 3.7
+ *
+ * parameter     = token "=" ( token | quoted-string )
+ * token         = 1*<any CHAR except CTLs or separators>
+ * separators    = "(" | ")" | "<" | ">" | "@"
+ *               | "," | ";" | ":" | "\" | <">
+ *               | "/" | "[" | "]" | "?" | "="
+ *               | "{" | "}" | SP | HT
+ * quoted-string = ( <"> *(qdtext | quoted-pair ) <"> )
+ * qdtext        = <any TEXT except <">>
+ * quoted-pair   = "\" CHAR
+ * CHAR          = <any US-ASCII character (octets 0 - 127)>
+ * TEXT          = <any OCTET except CTLs, but including LWS>
+ * LWS           = [CRLF] 1*( SP | HT )
+ * CRLF          = CR LF
+ * CR            = <US-ASCII CR, carriage return (13)>
+ * LF            = <US-ASCII LF, linefeed (10)>
+ * SP            = <US-ASCII SP, space (32)>
+ * SHT           = <US-ASCII HT, horizontal-tab (9)>
+ * CTL           = <any US-ASCII control character (octets 0 - 31) and DEL (127)>
+ * OCTET         = <any 8-bit sequence of data>
+ */
+var paramRegExp = /; *([!#$%&'\*\+\-\.0-9A-Z\^_`a-z\|~]+) *= *("(?:[ !\u0023-\u005b\u005d-\u007e\u0080-\u00ff]|\\[\u0020-\u007e])*"|[!#$%&'\*\+\-\.0-9A-Z\^_`a-z\|~]+) */g;
+var textRegExp = /^[\u0020-\u007e\u0080-\u00ff]+$/
+var tokenRegExp = /^[!#$%&'\*\+\-\.0-9A-Z\^_`a-z\|~]+$/
+
+/**
+ * RegExp to match quoted-pair in RFC 2616
+ *
+ * quoted-pair = "\" CHAR
+ * CHAR        = <any US-ASCII character (octets 0 - 127)>
+ */
+var qescRegExp = /\\([\u0000-\u007f])/g;
+
+/**
+ * RegExp to match chars that must be quoted-pair in RFC 2616
+ */
+var quoteRegExp = /([\\"])/g;
+
+/**
+ * RegExp to match type in RFC 6838
+ *
+ * type-name = restricted-name
+ * subtype-name = restricted-name
+ * restricted-name = restricted-name-first *126restricted-name-chars
+ * restricted-name-first  = ALPHA / DIGIT
+ * restricted-name-chars  = ALPHA / DIGIT / "!" / "#" /
+ *                          "$" / "&" / "-" / "^" / "_"
+ * restricted-name-chars =/ "." ; Characters before first dot always
+ *                              ; specify a facet name
+ * restricted-name-chars =/ "+" ; Characters after last plus always
+ *                              ; specify a structured syntax suffix
+ * ALPHA =  %x41-5A / %x61-7A   ; A-Z / a-z
+ * DIGIT =  %x30-39             ; 0-9
+ */
+var subtypeNameRegExp = /^[A-Za-z0-9][A-Za-z0-9!#$&^_.-]{0,126}$/
+var typeNameRegExp = /^[A-Za-z0-9][A-Za-z0-9!#$&^_-]{0,126}$/
+var typeRegExp = /^ *([A-Za-z0-9][A-Za-z0-9!#$&^_-]{0,126})\/([A-Za-z0-9][A-Za-z0-9!#$&^_.+-]{0,126}) *$/;
+
+/**
+ * Module exports.
+ */
+
+exports.format = format
+exports.parse = parse
+
+/**
+ * Format object to media type.
+ *
+ * @param {object} obj
+ * @return {string}
+ * @api public
+ */
+
+function format(obj) {
+  if (!obj || typeof obj !== 'object') {
+    throw new TypeError('argument obj is required')
+  }
+
+  var parameters = obj.parameters
+  var subtype = obj.subtype
+  var suffix = obj.suffix
+  var type = obj.type
+
+  if (!type || !typeNameRegExp.test(type)) {
+    throw new TypeError('invalid type')
+  }
+
+  if (!subtype || !subtypeNameRegExp.test(subtype)) {
+    throw new TypeError('invalid subtype')
+  }
+
+  // format as type/subtype
+  var string = type + '/' + subtype
+
+  // append +suffix
+  if (suffix) {
+    if (!typeNameRegExp.test(suffix)) {
+      throw new TypeError('invalid suffix')
+    }
+
+    string += '+' + suffix
+  }
+
+  // append parameters
+  if (parameters && typeof parameters === 'object') {
+    var param
+    var params = Object.keys(parameters).sort()
+
+    for (var i = 0; i < params.length; i++) {
+      param = params[i]
+
+      if (!tokenRegExp.test(param)) {
+        throw new TypeError('invalid parameter name')
+      }
+
+      string += '; ' + param + '=' + qstring(parameters[param])
+    }
+  }
+
+  return string
+}
+
+/**
+ * Parse media type to object.
+ *
+ * @param {string|object} string
+ * @return {Object}
+ * @api public
+ */
+
+function parse(string) {
+  if (!string) {
+    throw new TypeError('argument string is required')
+  }
+
+  // support req/res-like objects as argument
+  if (typeof string === 'object') {
+    string = getcontenttype(string)
+  }
+
+  if (typeof string !== 'string') {
+    throw new TypeError('argument string is required to be a string')
+  }
+
+  var index = string.indexOf(';')
+  var type = index !== -1
+    ? string.substr(0, index)
+    : string
+
+  var key
+  var match
+  var obj = splitType(type)
+  var params = {}
+  var value
+
+  paramRegExp.lastIndex = index
+
+  while (match = paramRegExp.exec(string)) {
+    if (match.index !== index) {
+      throw new TypeError('invalid parameter format')
+    }
+
+    index += match[0].length
+    key = match[1].toLowerCase()
+    value = match[2]
+
+    if (value[0] === '"') {
+      // remove quotes and escapes
+      value = value
+        .substr(1, value.length - 2)
+        .replace(qescRegExp, '$1')
+    }
+
+    params[key] = value
+  }
+
+  if (index !== -1 && index !== string.length) {
+    throw new TypeError('invalid parameter format')
+  }
+
+  obj.parameters = params
+
+  return obj
+}
+
+/**
+ * Get content-type from req/res objects.
+ *
+ * @param {object}
+ * @return {Object}
+ * @api private
+ */
+
+function getcontenttype(obj) {
+  if (typeof obj.getHeader === 'function') {
+    // res-like
+    return obj.getHeader('content-type')
+  }
+
+  if (typeof obj.headers === 'object') {
+    // req-like
+    return obj.headers && obj.headers['content-type']
+  }
+}
+
+/**
+ * Quote a string if necessary.
+ *
+ * @param {string} val
+ * @return {string}
+ * @api private
+ */
+
+function qstring(val) {
+  var str = String(val)
+
+  // no need to quote tokens
+  if (tokenRegExp.test(str)) {
+    return str
+  }
+
+  if (str.length > 0 && !textRegExp.test(str)) {
+    throw new TypeError('invalid parameter value')
+  }
+
+  return '"' + str.replace(quoteRegExp, '\\$1') + '"'
+}
+
+/**
+ * Simply "type/subtype+siffx" into parts.
+ *
+ * @param {string} string
+ * @return {Object}
+ * @api private
+ */
+
+function splitType(string) {
+  var match = typeRegExp.exec(string.toLowerCase())
+
+  if (!match) {
+    throw new TypeError('invalid media type')
+  }
+
+  var type = match[1]
+  var subtype = match[2]
+  var suffix
+
+  // suffix after last +
+  var index = subtype.lastIndexOf('+')
+  if (index !== -1) {
+    suffix = subtype.substr(index + 1)
+    subtype = subtype.substr(0, index)
+  }
+
+  var obj = {
+    type: type,
+    subtype: subtype,
+    suffix: suffix
+  }
+
+  return obj
+}
diff --git a/server/node_modules/media-typer/package.json b/server/node_modules/media-typer/package.json
new file mode 100644
index 0000000..8cf3ebc
--- /dev/null
+++ b/server/node_modules/media-typer/package.json
@@ -0,0 +1,26 @@
+{
+  "name": "media-typer",
+  "description": "Simple RFC 6838 media type parser and formatter",
+  "version": "0.3.0",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "repository": "jshttp/media-typer",
+  "devDependencies": {
+    "istanbul": "0.3.2",
+    "mocha": "~1.21.4",
+    "should": "~4.0.4"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "test": "mocha --reporter spec --check-leaks --bail test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  }
+}
diff --git a/server/node_modules/merge-descriptors/HISTORY.md b/server/node_modules/merge-descriptors/HISTORY.md
new file mode 100644
index 0000000..486771f
--- /dev/null
+++ b/server/node_modules/merge-descriptors/HISTORY.md
@@ -0,0 +1,21 @@
+1.0.1 / 2016-01-17
+==================
+
+  * perf: enable strict mode
+
+1.0.0 / 2015-03-01
+==================
+
+  * Add option to only add new descriptors
+  * Add simple argument validation
+  * Add jsdoc to source file
+
+0.0.2 / 2013-12-14
+==================
+
+  * Move repository to `component` organization
+
+0.0.1 / 2013-10-29
+==================
+
+  * Initial release
diff --git a/server/node_modules/merge-descriptors/LICENSE b/server/node_modules/merge-descriptors/LICENSE
new file mode 100644
index 0000000..274bfd8
--- /dev/null
+++ b/server/node_modules/merge-descriptors/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2013 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/merge-descriptors/README.md b/server/node_modules/merge-descriptors/README.md
new file mode 100644
index 0000000..3403f4a
--- /dev/null
+++ b/server/node_modules/merge-descriptors/README.md
@@ -0,0 +1,49 @@
+# merge-descriptors
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Merge objects using descriptors.
+
+```js
+var thing = {
+  get name() {
+    return 'jon'
+  }
+}
+
+var animal = {
+
+}
+
+merge(animal, thing)
+
+animal.name === 'jon'
+```
+
+## API
+
+### merge(destination, source)
+
+Redefines `destination`'s descriptors with `source`'s. The return value is the
+`destination` object.
+
+### merge(destination, source, false)
+
+Defines `source`'s descriptors on `destination` if `destination` does not have
+a descriptor by the same name. The return value is the `destination` object.
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/merge-descriptors.svg
+[npm-url]: https://npmjs.org/package/merge-descriptors
+[travis-image]: https://img.shields.io/travis/component/merge-descriptors/master.svg
+[travis-url]: https://travis-ci.org/component/merge-descriptors
+[coveralls-image]: https://img.shields.io/coveralls/component/merge-descriptors/master.svg
+[coveralls-url]: https://coveralls.io/r/component/merge-descriptors?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/merge-descriptors.svg
+[downloads-url]: https://npmjs.org/package/merge-descriptors
diff --git a/server/node_modules/merge-descriptors/index.js b/server/node_modules/merge-descriptors/index.js
new file mode 100644
index 0000000..f22ebab
--- /dev/null
+++ b/server/node_modules/merge-descriptors/index.js
@@ -0,0 +1,60 @@
+/*!
+ * merge-descriptors
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = merge
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var hasOwnProperty = Object.prototype.hasOwnProperty
+
+/**
+ * Merge the property descriptors of `src` into `dest`
+ *
+ * @param {object} dest Object to add descriptors to
+ * @param {object} src Object to clone descriptors from
+ * @param {boolean} [redefine=true] Redefine `dest` properties with `src` properties
+ * @returns {object} Reference to dest
+ * @public
+ */
+
+function merge (dest, src, redefine) {
+  if (!dest) {
+    throw new TypeError('argument dest is required')
+  }
+
+  if (!src) {
+    throw new TypeError('argument src is required')
+  }
+
+  if (redefine === undefined) {
+    // Default to true
+    redefine = true
+  }
+
+  Object.getOwnPropertyNames(src).forEach(function forEachOwnPropertyName (name) {
+    if (!redefine && hasOwnProperty.call(dest, name)) {
+      // Skip descriptor
+      return
+    }
+
+    // Copy descriptor
+    var descriptor = Object.getOwnPropertyDescriptor(src, name)
+    Object.defineProperty(dest, name, descriptor)
+  })
+
+  return dest
+}
diff --git a/server/node_modules/merge-descriptors/package.json b/server/node_modules/merge-descriptors/package.json
new file mode 100644
index 0000000..aa9af0a
--- /dev/null
+++ b/server/node_modules/merge-descriptors/package.json
@@ -0,0 +1,39 @@
+{
+  "name": "merge-descriptors",
+  "description": "Merge objects using descriptors",
+  "version": "1.0.3",
+  "author": {
+    "name": "Jonathan Ong",
+    "email": "me@jongleberry.com",
+    "url": "http://jongleberry.com",
+    "twitter": "https://twitter.com/jongleberry"
+  },
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Mike Grabowski <grabbou@gmail.com>"
+  ],
+  "license": "MIT",
+  "repository": "sindresorhus/merge-descriptors",
+  "funding": "https://github.com/sponsors/sindresorhus",
+  "devDependencies": {
+    "eslint": "5.9.0",
+    "eslint-config-standard": "12.0.0",
+    "eslint-plugin-import": "2.14.0",
+    "eslint-plugin-node": "7.0.1",
+    "eslint-plugin-promise": "4.0.1",
+    "eslint-plugin-standard": "4.0.0",
+    "mocha": "5.2.0",
+    "nyc": "13.1.0"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "README.md",
+    "index.js"
+  ],
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha test/",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/methods/HISTORY.md b/server/node_modules/methods/HISTORY.md
new file mode 100644
index 0000000..c0ecf07
--- /dev/null
+++ b/server/node_modules/methods/HISTORY.md
@@ -0,0 +1,29 @@
+1.1.2 / 2016-01-17
+==================
+
+  * perf: enable strict mode
+
+1.1.1 / 2014-12-30
+==================
+
+  * Improve `browserify` support
+
+1.1.0 / 2014-07-05
+==================
+
+  * Add `CONNECT` method
+ 
+1.0.1 / 2014-06-02
+==================
+
+  * Fix module to work with harmony transform
+
+1.0.0 / 2014-05-08
+==================
+
+  * Add `PURGE` method
+
+0.1.0 / 2013-10-28
+==================
+
+  * Add `http.METHODS` support
diff --git a/server/node_modules/methods/LICENSE b/server/node_modules/methods/LICENSE
new file mode 100644
index 0000000..220dc1a
--- /dev/null
+++ b/server/node_modules/methods/LICENSE
@@ -0,0 +1,24 @@
+(The MIT License)
+
+Copyright (c) 2013-2014 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2015-2016 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/methods/README.md b/server/node_modules/methods/README.md
new file mode 100644
index 0000000..672a32b
--- /dev/null
+++ b/server/node_modules/methods/README.md
@@ -0,0 +1,51 @@
+# Methods
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+HTTP verbs that Node.js core's HTTP parser supports.
+
+This module provides an export that is just like `http.METHODS` from Node.js core,
+with the following differences:
+
+  * All method names are lower-cased.
+  * Contains a fallback list of methods for Node.js versions that do not have a
+    `http.METHODS` export (0.10 and lower).
+  * Provides the fallback list when using tools like `browserify` without pulling
+    in the `http` shim module.
+
+## Install
+
+```bash
+$ npm install methods
+```
+
+## API
+
+```js
+var methods = require('methods')
+```
+
+### methods
+
+This is an array of lower-cased method names that Node.js supports. If Node.js
+provides the `http.METHODS` export, then this is the same array lower-cased,
+otherwise it is a snapshot of the verbs from Node.js 0.10.
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/methods.svg?style=flat
+[npm-url]: https://npmjs.org/package/methods
+[node-version-image]: https://img.shields.io/node/v/methods.svg?style=flat
+[node-version-url]: https://nodejs.org/en/download/
+[travis-image]: https://img.shields.io/travis/jshttp/methods.svg?style=flat
+[travis-url]: https://travis-ci.org/jshttp/methods
+[coveralls-image]: https://img.shields.io/coveralls/jshttp/methods.svg?style=flat
+[coveralls-url]: https://coveralls.io/r/jshttp/methods?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/methods.svg?style=flat
+[downloads-url]: https://npmjs.org/package/methods
diff --git a/server/node_modules/methods/index.js b/server/node_modules/methods/index.js
new file mode 100644
index 0000000..667a50b
--- /dev/null
+++ b/server/node_modules/methods/index.js
@@ -0,0 +1,69 @@
+/*!
+ * methods
+ * Copyright(c) 2013-2014 TJ Holowaychuk
+ * Copyright(c) 2015-2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var http = require('http');
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = getCurrentNodeMethods() || getBasicNodeMethods();
+
+/**
+ * Get the current Node.js methods.
+ * @private
+ */
+
+function getCurrentNodeMethods() {
+  return http.METHODS && http.METHODS.map(function lowerCaseMethod(method) {
+    return method.toLowerCase();
+  });
+}
+
+/**
+ * Get the "basic" Node.js methods, a snapshot from Node.js 0.10.
+ * @private
+ */
+
+function getBasicNodeMethods() {
+  return [
+    'get',
+    'post',
+    'put',
+    'head',
+    'delete',
+    'options',
+    'trace',
+    'copy',
+    'lock',
+    'mkcol',
+    'move',
+    'purge',
+    'propfind',
+    'proppatch',
+    'unlock',
+    'report',
+    'mkactivity',
+    'checkout',
+    'merge',
+    'm-search',
+    'notify',
+    'subscribe',
+    'unsubscribe',
+    'patch',
+    'search',
+    'connect'
+  ];
+}
diff --git a/server/node_modules/methods/package.json b/server/node_modules/methods/package.json
new file mode 100644
index 0000000..c4ce6f0
--- /dev/null
+++ b/server/node_modules/methods/package.json
@@ -0,0 +1,36 @@
+{
+  "name": "methods",
+  "description": "HTTP methods that node supports",
+  "version": "1.1.2",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)",
+    "TJ Holowaychuk <tj@vision-media.ca> (http://tjholowaychuk.com)"
+  ],
+  "license": "MIT",
+  "repository": "jshttp/methods",
+  "devDependencies": {
+    "istanbul": "0.4.1",
+    "mocha": "1.21.5"
+  },
+  "files": [
+    "index.js",
+    "HISTORY.md",
+    "LICENSE"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  },
+  "browser": {
+    "http": false
+  },
+  "keywords": [
+    "http",
+    "methods"
+  ]
+}
diff --git a/server/node_modules/mime-db/HISTORY.md b/server/node_modules/mime-db/HISTORY.md
new file mode 100644
index 0000000..7436f64
--- /dev/null
+++ b/server/node_modules/mime-db/HISTORY.md
@@ -0,0 +1,507 @@
+1.52.0 / 2022-02-21
+===================
+
+  * Add extensions from IANA for more `image/*` types
+  * Add extension `.asc` to `application/pgp-keys`
+  * Add extensions to various XML types
+  * Add new upstream MIME types
+
+1.51.0 / 2021-11-08
+===================
+
+  * Add new upstream MIME types
+  * Mark `image/vnd.microsoft.icon` as compressible
+  * Mark `image/vnd.ms-dds` as compressible
+
+1.50.0 / 2021-09-15
+===================
+
+  * Add deprecated iWorks mime types and extensions
+  * Add new upstream MIME types
+
+1.49.0 / 2021-07-26
+===================
+
+  * Add extension `.trig` to `application/trig`
+  * Add new upstream MIME types
+
+1.48.0 / 2021-05-30
+===================
+
+  * Add extension `.mvt` to `application/vnd.mapbox-vector-tile`
+  * Add new upstream MIME types
+  * Mark `text/yaml` as compressible
+
+1.47.0 / 2021-04-01
+===================
+
+  * Add new upstream MIME types
+  * Remove ambigious extensions from IANA for `application/*+xml` types
+  * Update primary extension to `.es` for `application/ecmascript`
+
+1.46.0 / 2021-02-13
+===================
+
+  * Add extension `.amr` to `audio/amr`
+  * Add extension `.m4s` to `video/iso.segment`
+  * Add extension `.opus` to `audio/ogg`
+  * Add new upstream MIME types
+
+1.45.0 / 2020-09-22
+===================
+
+  * Add `application/ubjson` with extension `.ubj`
+  * Add `image/avif` with extension `.avif`
+  * Add `image/ktx2` with extension `.ktx2`
+  * Add extension `.dbf` to `application/vnd.dbf`
+  * Add extension `.rar` to `application/vnd.rar`
+  * Add extension `.td` to `application/urc-targetdesc+xml`
+  * Add new upstream MIME types
+  * Fix extension of `application/vnd.apple.keynote` to be `.key`
+
+1.44.0 / 2020-04-22
+===================
+
+  * Add charsets from IANA
+  * Add extension `.cjs` to `application/node`
+  * Add new upstream MIME types
+
+1.43.0 / 2020-01-05
+===================
+
+  * Add `application/x-keepass2` with extension `.kdbx`
+  * Add extension `.mxmf` to `audio/mobile-xmf`
+  * Add extensions from IANA for `application/*+xml` types
+  * Add new upstream MIME types
+
+1.42.0 / 2019-09-25
+===================
+
+  * Add `image/vnd.ms-dds` with extension `.dds`
+  * Add new upstream MIME types
+  * Remove compressible from `multipart/mixed`
+
+1.41.0 / 2019-08-30
+===================
+
+  * Add new upstream MIME types
+  * Add `application/toml` with extension `.toml`
+  * Mark `font/ttf` as compressible
+
+1.40.0 / 2019-04-20
+===================
+
+  * Add extensions from IANA for `model/*` types
+  * Add `text/mdx` with extension `.mdx`
+
+1.39.0 / 2019-04-04
+===================
+
+  * Add extensions `.siv` and `.sieve` to `application/sieve`
+  * Add new upstream MIME types
+
+1.38.0 / 2019-02-04
+===================
+
+  * Add extension `.nq` to `application/n-quads`
+  * Add extension `.nt` to `application/n-triples`
+  * Add new upstream MIME types
+  * Mark `text/less` as compressible
+
+1.37.0 / 2018-10-19
+===================
+
+  * Add extensions to HEIC image types
+  * Add new upstream MIME types
+
+1.36.0 / 2018-08-20
+===================
+
+  * Add Apple file extensions from IANA
+  * Add extensions from IANA for `image/*` types
+  * Add new upstream MIME types
+
+1.35.0 / 2018-07-15
+===================
+
+  * Add extension `.owl` to `application/rdf+xml`
+  * Add new upstream MIME types
+    - Removes extension `.woff` from `application/font-woff`
+
+1.34.0 / 2018-06-03
+===================
+
+  * Add extension `.csl` to `application/vnd.citationstyles.style+xml`
+  * Add extension `.es` to `application/ecmascript`
+  * Add new upstream MIME types
+  * Add `UTF-8` as default charset for `text/turtle`
+  * Mark all XML-derived types as compressible
+
+1.33.0 / 2018-02-15
+===================
+
+  * Add extensions from IANA for `message/*` types
+  * Add new upstream MIME types
+  * Fix some incorrect OOXML types
+  * Remove `application/font-woff2`
+
+1.32.0 / 2017-11-29
+===================
+
+  * Add new upstream MIME types
+  * Update `text/hjson` to registered `application/hjson`
+  * Add `text/shex` with extension `.shex`
+
+1.31.0 / 2017-10-25
+===================
+
+  * Add `application/raml+yaml` with extension `.raml`
+  * Add `application/wasm` with extension `.wasm`
+  * Add new `font` type from IANA
+  * Add new upstream font extensions
+  * Add new upstream MIME types
+  * Add extensions for JPEG-2000 images
+
+1.30.0 / 2017-08-27
+===================
+
+  * Add `application/vnd.ms-outlook`
+  * Add `application/x-arj`
+  * Add extension `.mjs` to `application/javascript`
+  * Add glTF types and extensions
+  * Add new upstream MIME types
+  * Add `text/x-org`
+  * Add VirtualBox MIME types
+  * Fix `source` records for `video/*` types that are IANA
+  * Update `font/opentype` to registered `font/otf`
+
+1.29.0 / 2017-07-10
+===================
+
+  * Add `application/fido.trusted-apps+json`
+  * Add extension `.wadl` to `application/vnd.sun.wadl+xml`
+  * Add new upstream MIME types
+  * Add `UTF-8` as default charset for `text/css`
+
+1.28.0 / 2017-05-14
+===================
+
+  * Add new upstream MIME types
+  * Add extension `.gz` to `application/gzip`
+  * Update extensions `.md` and `.markdown` to be `text/markdown`
+
+1.27.0 / 2017-03-16
+===================
+
+  * Add new upstream MIME types
+  * Add `image/apng` with extension `.apng`
+
+1.26.0 / 2017-01-14
+===================
+
+  * Add new upstream MIME types
+  * Add extension `.geojson` to `application/geo+json`
+
+1.25.0 / 2016-11-11
+===================
+
+  * Add new upstream MIME types
+
+1.24.0 / 2016-09-18
+===================
+
+  * Add `audio/mp3`
+  * Add new upstream MIME types
+
+1.23.0 / 2016-05-01
+===================
+
+  * Add new upstream MIME types
+  * Add extension `.3gpp` to `audio/3gpp`
+
+1.22.0 / 2016-02-15
+===================
+
+  * Add `text/slim`
+  * Add extension `.rng` to `application/xml`
+  * Add new upstream MIME types
+  * Fix extension of `application/dash+xml` to be `.mpd`
+  * Update primary extension to `.m4a` for `audio/mp4`
+
+1.21.0 / 2016-01-06
+===================
+
+  * Add Google document types
+  * Add new upstream MIME types
+
+1.20.0 / 2015-11-10
+===================
+
+  * Add `text/x-suse-ymp`
+  * Add new upstream MIME types
+
+1.19.0 / 2015-09-17
+===================
+
+  * Add `application/vnd.apple.pkpass`
+  * Add new upstream MIME types
+
+1.18.0 / 2015-09-03
+===================
+
+  * Add new upstream MIME types
+
+1.17.0 / 2015-08-13
+===================
+
+  * Add `application/x-msdos-program`
+  * Add `audio/g711-0`
+  * Add `image/vnd.mozilla.apng`
+  * Add extension `.exe` to `application/x-msdos-program`
+
+1.16.0 / 2015-07-29
+===================
+
+  * Add `application/vnd.uri-map`
+
+1.15.0 / 2015-07-13
+===================
+
+  * Add `application/x-httpd-php`
+
+1.14.0 / 2015-06-25
+===================
+
+  * Add `application/scim+json`
+  * Add `application/vnd.3gpp.ussd+xml`
+  * Add `application/vnd.biopax.rdf+xml`
+  * Add `text/x-processing`
+
+1.13.0 / 2015-06-07
+===================
+
+  * Add nginx as a source
+  * Add `application/x-cocoa`
+  * Add `application/x-java-archive-diff`
+  * Add `application/x-makeself`
+  * Add `application/x-perl`
+  * Add `application/x-pilot`
+  * Add `application/x-redhat-package-manager`
+  * Add `application/x-sea`
+  * Add `audio/x-m4a`
+  * Add `audio/x-realaudio`
+  * Add `image/x-jng`
+  * Add `text/mathml`
+
+1.12.0 / 2015-06-05
+===================
+
+  * Add `application/bdoc`
+  * Add `application/vnd.hyperdrive+json`
+  * Add `application/x-bdoc`
+  * Add extension `.rtf` to `text/rtf`
+
+1.11.0 / 2015-05-31
+===================
+
+  * Add `audio/wav`
+  * Add `audio/wave`
+  * Add extension `.litcoffee` to `text/coffeescript`
+  * Add extension `.sfd-hdstx` to `application/vnd.hydrostatix.sof-data`
+  * Add extension `.n-gage` to `application/vnd.nokia.n-gage.symbian.install`
+
+1.10.0 / 2015-05-19
+===================
+
+  * Add `application/vnd.balsamiq.bmpr`
+  * Add `application/vnd.microsoft.portable-executable`
+  * Add `application/x-ns-proxy-autoconfig`
+
+1.9.1 / 2015-04-19
+==================
+
+  * Remove `.json` extension from `application/manifest+json`
+    - This is causing bugs downstream
+
+1.9.0 / 2015-04-19
+==================
+
+  * Add `application/manifest+json`
+  * Add `application/vnd.micro+json`
+  * Add `image/vnd.zbrush.pcx`
+  * Add `image/x-ms-bmp`
+
+1.8.0 / 2015-03-13
+==================
+
+  * Add `application/vnd.citationstyles.style+xml`
+  * Add `application/vnd.fastcopy-disk-image`
+  * Add `application/vnd.gov.sk.xmldatacontainer+xml`
+  * Add extension `.jsonld` to `application/ld+json`
+
+1.7.0 / 2015-02-08
+==================
+
+  * Add `application/vnd.gerber`
+  * Add `application/vnd.msa-disk-image`
+
+1.6.1 / 2015-02-05
+==================
+
+  * Community extensions ownership transferred from `node-mime`
+
+1.6.0 / 2015-01-29
+==================
+
+  * Add `application/jose`
+  * Add `application/jose+json`
+  * Add `application/json-seq`
+  * Add `application/jwk+json`
+  * Add `application/jwk-set+json`
+  * Add `application/jwt`
+  * Add `application/rdap+json`
+  * Add `application/vnd.gov.sk.e-form+xml`
+  * Add `application/vnd.ims.imsccv1p3`
+
+1.5.0 / 2014-12-30
+==================
+
+  * Add `application/vnd.oracle.resource+json`
+  * Fix various invalid MIME type entries
+    - `application/mbox+xml`
+    - `application/oscp-response`
+    - `application/vwg-multiplexed`
+    - `audio/g721`
+
+1.4.0 / 2014-12-21
+==================
+
+  * Add `application/vnd.ims.imsccv1p2`
+  * Fix various invalid MIME type entries
+    - `application/vnd-acucobol`
+    - `application/vnd-curl`
+    - `application/vnd-dart`
+    - `application/vnd-dxr`
+    - `application/vnd-fdf`
+    - `application/vnd-mif`
+    - `application/vnd-sema`
+    - `application/vnd-wap-wmlc`
+    - `application/vnd.adobe.flash-movie`
+    - `application/vnd.dece-zip`
+    - `application/vnd.dvb_service`
+    - `application/vnd.micrografx-igx`
+    - `application/vnd.sealed-doc`
+    - `application/vnd.sealed-eml`
+    - `application/vnd.sealed-mht`
+    - `application/vnd.sealed-ppt`
+    - `application/vnd.sealed-tiff`
+    - `application/vnd.sealed-xls`
+    - `application/vnd.sealedmedia.softseal-html`
+    - `application/vnd.sealedmedia.softseal-pdf`
+    - `application/vnd.wap-slc`
+    - `application/vnd.wap-wbxml`
+    - `audio/vnd.sealedmedia.softseal-mpeg`
+    - `image/vnd-djvu`
+    - `image/vnd-svf`
+    - `image/vnd-wap-wbmp`
+    - `image/vnd.sealed-png`
+    - `image/vnd.sealedmedia.softseal-gif`
+    - `image/vnd.sealedmedia.softseal-jpg`
+    - `model/vnd-dwf`
+    - `model/vnd.parasolid.transmit-binary`
+    - `model/vnd.parasolid.transmit-text`
+    - `text/vnd-a`
+    - `text/vnd-curl`
+    - `text/vnd.wap-wml`
+  * Remove example template MIME types
+    - `application/example`
+    - `audio/example`
+    - `image/example`
+    - `message/example`
+    - `model/example`
+    - `multipart/example`
+    - `text/example`
+    - `video/example`
+
+1.3.1 / 2014-12-16
+==================
+
+  * Fix missing extensions
+    - `application/json5`
+    - `text/hjson`
+
+1.3.0 / 2014-12-07
+==================
+
+  * Add `application/a2l`
+  * Add `application/aml`
+  * Add `application/atfx`
+  * Add `application/atxml`
+  * Add `application/cdfx+xml`
+  * Add `application/dii`
+  * Add `application/json5`
+  * Add `application/lxf`
+  * Add `application/mf4`
+  * Add `application/vnd.apache.thrift.compact`
+  * Add `application/vnd.apache.thrift.json`
+  * Add `application/vnd.coffeescript`
+  * Add `application/vnd.enphase.envoy`
+  * Add `application/vnd.ims.imsccv1p1`
+  * Add `text/csv-schema`
+  * Add `text/hjson`
+  * Add `text/markdown`
+  * Add `text/yaml`
+
+1.2.0 / 2014-11-09
+==================
+
+  * Add `application/cea`
+  * Add `application/dit`
+  * Add `application/vnd.gov.sk.e-form+zip`
+  * Add `application/vnd.tmd.mediaflex.api+xml`
+  * Type `application/epub+zip` is now IANA-registered
+
+1.1.2 / 2014-10-23
+==================
+
+  * Rebuild database for `application/x-www-form-urlencoded` change
+
+1.1.1 / 2014-10-20
+==================
+
+  * Mark `application/x-www-form-urlencoded` as compressible.
+
+1.1.0 / 2014-09-28
+==================
+
+  * Add `application/font-woff2`
+
+1.0.3 / 2014-09-25
+==================
+
+  * Fix engine requirement in package
+
+1.0.2 / 2014-09-25
+==================
+
+  * Add `application/coap-group+json`
+  * Add `application/dcd`
+  * Add `application/vnd.apache.thrift.binary`
+  * Add `image/vnd.tencent.tap`
+  * Mark all JSON-derived types as compressible
+  * Update `text/vtt` data
+
+1.0.1 / 2014-08-30
+==================
+
+  * Fix extension ordering
+
+1.0.0 / 2014-08-30
+==================
+
+  * Add `application/atf`
+  * Add `application/merge-patch+json`
+  * Add `multipart/x-mixed-replace`
+  * Add `source: 'apache'` metadata
+  * Add `source: 'iana'` metadata
+  * Remove badly-assumed charset data
diff --git a/server/node_modules/mime-db/LICENSE b/server/node_modules/mime-db/LICENSE
new file mode 100644
index 0000000..0751cb1
--- /dev/null
+++ b/server/node_modules/mime-db/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2014 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2015-2022 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/mime-db/README.md b/server/node_modules/mime-db/README.md
new file mode 100644
index 0000000..5a8fcfe
--- /dev/null
+++ b/server/node_modules/mime-db/README.md
@@ -0,0 +1,100 @@
+# mime-db
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][ci-image]][ci-url]
+[![Coverage Status][coveralls-image]][coveralls-url]
+
+This is a large database of mime types and information about them.
+It consists of a single, public JSON file and does not include any logic,
+allowing it to remain as un-opinionated as possible with an API.
+It aggregates data from the following sources:
+
+- http://www.iana.org/assignments/media-types/media-types.xhtml
+- http://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types
+- http://hg.nginx.org/nginx/raw-file/default/conf/mime.types
+
+## Installation
+
+```bash
+npm install mime-db
+```
+
+### Database Download
+
+If you're crazy enough to use this in the browser, you can just grab the
+JSON file using [jsDelivr](https://www.jsdelivr.com/). It is recommended to
+replace `master` with [a release tag](https://github.com/jshttp/mime-db/tags)
+as the JSON format may change in the future.
+
+```
+https://cdn.jsdelivr.net/gh/jshttp/mime-db@master/db.json
+```
+
+## Usage
+
+```js
+var db = require('mime-db')
+
+// grab data on .js files
+var data = db['application/javascript']
+```
+
+## Data Structure
+
+The JSON file is a map lookup for lowercased mime types.
+Each mime type has the following properties:
+
+- `.source` - where the mime type is defined.
+    If not set, it's probably a custom media type.
+    - `apache` - [Apache common media types](http://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types)
+    - `iana` - [IANA-defined media types](http://www.iana.org/assignments/media-types/media-types.xhtml)
+    - `nginx` - [nginx media types](http://hg.nginx.org/nginx/raw-file/default/conf/mime.types)
+- `.extensions[]` - known extensions associated with this mime type.
+- `.compressible` - whether a file of this type can be gzipped.
+- `.charset` - the default charset associated with this type, if any.
+
+If unknown, every property could be `undefined`.
+
+## Contributing
+
+To edit the database, only make PRs against `src/custom-types.json` or
+`src/custom-suffix.json`.
+
+The `src/custom-types.json` file is a JSON object with the MIME type as the
+keys and the values being an object with the following keys:
+
+- `compressible` - leave out if you don't know, otherwise `true`/`false` to
+  indicate whether the data represented by the type is typically compressible.
+- `extensions` - include an array of file extensions that are associated with
+  the type.
+- `notes` - human-readable notes about the type, typically what the type is.
+- `sources` - include an array of URLs of where the MIME type and the associated
+  extensions are sourced from. This needs to be a [primary source](https://en.wikipedia.org/wiki/Primary_source);
+  links to type aggregating sites and Wikipedia are _not acceptable_.
+
+To update the build, run `npm run build`.
+
+### Adding Custom Media Types
+
+The best way to get new media types included in this library is to register
+them with the IANA. The community registration procedure is outlined in
+[RFC 6838 section 5](http://tools.ietf.org/html/rfc6838#section-5). Types
+registered with the IANA are automatically pulled into this library.
+
+If that is not possible / feasible, they can be added directly here as a
+"custom" type. To do this, it is required to have a primary source that
+definitively lists the media type. If an extension is going to be listed as
+associateed with this media type, the source must definitively link the
+media type and extension as well.
+
+[ci-image]: https://badgen.net/github/checks/jshttp/mime-db/master?label=ci
+[ci-url]: https://github.com/jshttp/mime-db/actions?query=workflow%3Aci
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/mime-db/master
+[coveralls-url]: https://coveralls.io/r/jshttp/mime-db?branch=master
+[node-image]: https://badgen.net/npm/node/mime-db
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/mime-db
+[npm-url]: https://npmjs.org/package/mime-db
+[npm-version-image]: https://badgen.net/npm/v/mime-db
diff --git a/server/node_modules/mime-db/db.json b/server/node_modules/mime-db/db.json
new file mode 100644
index 0000000..eb9c42c
--- /dev/null
+++ b/server/node_modules/mime-db/db.json
@@ -0,0 +1,8519 @@
+{
+  "application/1d-interleaved-parityfec": {
+    "source": "iana"
+  },
+  "application/3gpdash-qoe-report+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/3gpp-ims+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/3gpphal+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/3gpphalforms+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/a2l": {
+    "source": "iana"
+  },
+  "application/ace+cbor": {
+    "source": "iana"
+  },
+  "application/activemessage": {
+    "source": "iana"
+  },
+  "application/activity+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-costmap+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-costmapfilter+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-directory+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-endpointcost+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-endpointcostparams+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-endpointprop+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-endpointpropparams+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-error+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-networkmap+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-networkmapfilter+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-updatestreamcontrol+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/alto-updatestreamparams+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/aml": {
+    "source": "iana"
+  },
+  "application/andrew-inset": {
+    "source": "iana",
+    "extensions": ["ez"]
+  },
+  "application/applefile": {
+    "source": "iana"
+  },
+  "application/applixware": {
+    "source": "apache",
+    "extensions": ["aw"]
+  },
+  "application/at+jwt": {
+    "source": "iana"
+  },
+  "application/atf": {
+    "source": "iana"
+  },
+  "application/atfx": {
+    "source": "iana"
+  },
+  "application/atom+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["atom"]
+  },
+  "application/atomcat+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["atomcat"]
+  },
+  "application/atomdeleted+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["atomdeleted"]
+  },
+  "application/atomicmail": {
+    "source": "iana"
+  },
+  "application/atomsvc+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["atomsvc"]
+  },
+  "application/atsc-dwd+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["dwd"]
+  },
+  "application/atsc-dynamic-event-message": {
+    "source": "iana"
+  },
+  "application/atsc-held+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["held"]
+  },
+  "application/atsc-rdt+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/atsc-rsat+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["rsat"]
+  },
+  "application/atxml": {
+    "source": "iana"
+  },
+  "application/auth-policy+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/bacnet-xdd+zip": {
+    "source": "iana",
+    "compressible": false
+  },
+  "application/batch-smtp": {
+    "source": "iana"
+  },
+  "application/bdoc": {
+    "compressible": false,
+    "extensions": ["bdoc"]
+  },
+  "application/beep+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/calendar+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/calendar+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["xcs"]
+  },
+  "application/call-completion": {
+    "source": "iana"
+  },
+  "application/cals-1840": {
+    "source": "iana"
+  },
+  "application/captive+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/cbor": {
+    "source": "iana"
+  },
+  "application/cbor-seq": {
+    "source": "iana"
+  },
+  "application/cccex": {
+    "source": "iana"
+  },
+  "application/ccmp+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/ccxml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["ccxml"]
+  },
+  "application/cdfx+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["cdfx"]
+  },
+  "application/cdmi-capability": {
+    "source": "iana",
+    "extensions": ["cdmia"]
+  },
+  "application/cdmi-container": {
+    "source": "iana",
+    "extensions": ["cdmic"]
+  },
+  "application/cdmi-domain": {
+    "source": "iana",
+    "extensions": ["cdmid"]
+  },
+  "application/cdmi-object": {
+    "source": "iana",
+    "extensions": ["cdmio"]
+  },
+  "application/cdmi-queue": {
+    "source": "iana",
+    "extensions": ["cdmiq"]
+  },
+  "application/cdni": {
+    "source": "iana"
+  },
+  "application/cea": {
+    "source": "iana"
+  },
+  "application/cea-2018+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/cellml+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/cfw": {
+    "source": "iana"
+  },
+  "application/city+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/clr": {
+    "source": "iana"
+  },
+  "application/clue+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/clue_info+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/cms": {
+    "source": "iana"
+  },
+  "application/cnrp+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/coap-group+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/coap-payload": {
+    "source": "iana"
+  },
+  "application/commonground": {
+    "source": "iana"
+  },
+  "application/conference-info+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/cose": {
+    "source": "iana"
+  },
+  "application/cose-key": {
+    "source": "iana"
+  },
+  "application/cose-key-set": {
+    "source": "iana"
+  },
+  "application/cpl+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["cpl"]
+  },
+  "application/csrattrs": {
+    "source": "iana"
+  },
+  "application/csta+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/cstadata+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/csvm+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/cu-seeme": {
+    "source": "apache",
+    "extensions": ["cu"]
+  },
+  "application/cwt": {
+    "source": "iana"
+  },
+  "application/cybercash": {
+    "source": "iana"
+  },
+  "application/dart": {
+    "compressible": true
+  },
+  "application/dash+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mpd"]
+  },
+  "application/dash-patch+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mpp"]
+  },
+  "application/dashdelta": {
+    "source": "iana"
+  },
+  "application/davmount+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["davmount"]
+  },
+  "application/dca-rft": {
+    "source": "iana"
+  },
+  "application/dcd": {
+    "source": "iana"
+  },
+  "application/dec-dx": {
+    "source": "iana"
+  },
+  "application/dialog-info+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/dicom": {
+    "source": "iana"
+  },
+  "application/dicom+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/dicom+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/dii": {
+    "source": "iana"
+  },
+  "application/dit": {
+    "source": "iana"
+  },
+  "application/dns": {
+    "source": "iana"
+  },
+  "application/dns+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/dns-message": {
+    "source": "iana"
+  },
+  "application/docbook+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["dbk"]
+  },
+  "application/dots+cbor": {
+    "source": "iana"
+  },
+  "application/dskpp+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/dssc+der": {
+    "source": "iana",
+    "extensions": ["dssc"]
+  },
+  "application/dssc+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["xdssc"]
+  },
+  "application/dvcs": {
+    "source": "iana"
+  },
+  "application/ecmascript": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["es","ecma"]
+  },
+  "application/edi-consent": {
+    "source": "iana"
+  },
+  "application/edi-x12": {
+    "source": "iana",
+    "compressible": false
+  },
+  "application/edifact": {
+    "source": "iana",
+    "compressible": false
+  },
+  "application/efi": {
+    "source": "iana"
+  },
+  "application/elm+json": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/elm+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/emergencycalldata.cap+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/emergencycalldata.comment+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/emergencycalldata.control+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/emergencycalldata.deviceinfo+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/emergencycalldata.ecall.msd": {
+    "source": "iana"
+  },
+  "application/emergencycalldata.providerinfo+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/emergencycalldata.serviceinfo+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/emergencycalldata.subscriberinfo+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/emergencycalldata.veds+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/emma+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["emma"]
+  },
+  "application/emotionml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["emotionml"]
+  },
+  "application/encaprtp": {
+    "source": "iana"
+  },
+  "application/epp+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/epub+zip": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["epub"]
+  },
+  "application/eshop": {
+    "source": "iana"
+  },
+  "application/exi": {
+    "source": "iana",
+    "extensions": ["exi"]
+  },
+  "application/expect-ct-report+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/express": {
+    "source": "iana",
+    "extensions": ["exp"]
+  },
+  "application/fastinfoset": {
+    "source": "iana"
+  },
+  "application/fastsoap": {
+    "source": "iana"
+  },
+  "application/fdt+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["fdt"]
+  },
+  "application/fhir+json": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/fhir+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/fido.trusted-apps+json": {
+    "compressible": true
+  },
+  "application/fits": {
+    "source": "iana"
+  },
+  "application/flexfec": {
+    "source": "iana"
+  },
+  "application/font-sfnt": {
+    "source": "iana"
+  },
+  "application/font-tdpfr": {
+    "source": "iana",
+    "extensions": ["pfr"]
+  },
+  "application/font-woff": {
+    "source": "iana",
+    "compressible": false
+  },
+  "application/framework-attributes+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/geo+json": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["geojson"]
+  },
+  "application/geo+json-seq": {
+    "source": "iana"
+  },
+  "application/geopackage+sqlite3": {
+    "source": "iana"
+  },
+  "application/geoxacml+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/gltf-buffer": {
+    "source": "iana"
+  },
+  "application/gml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["gml"]
+  },
+  "application/gpx+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["gpx"]
+  },
+  "application/gxf": {
+    "source": "apache",
+    "extensions": ["gxf"]
+  },
+  "application/gzip": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["gz"]
+  },
+  "application/h224": {
+    "source": "iana"
+  },
+  "application/held+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/hjson": {
+    "extensions": ["hjson"]
+  },
+  "application/http": {
+    "source": "iana"
+  },
+  "application/hyperstudio": {
+    "source": "iana",
+    "extensions": ["stk"]
+  },
+  "application/ibe-key-request+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/ibe-pkg-reply+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/ibe-pp-data": {
+    "source": "iana"
+  },
+  "application/iges": {
+    "source": "iana"
+  },
+  "application/im-iscomposing+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/index": {
+    "source": "iana"
+  },
+  "application/index.cmd": {
+    "source": "iana"
+  },
+  "application/index.obj": {
+    "source": "iana"
+  },
+  "application/index.response": {
+    "source": "iana"
+  },
+  "application/index.vnd": {
+    "source": "iana"
+  },
+  "application/inkml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["ink","inkml"]
+  },
+  "application/iotp": {
+    "source": "iana"
+  },
+  "application/ipfix": {
+    "source": "iana",
+    "extensions": ["ipfix"]
+  },
+  "application/ipp": {
+    "source": "iana"
+  },
+  "application/isup": {
+    "source": "iana"
+  },
+  "application/its+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["its"]
+  },
+  "application/java-archive": {
+    "source": "apache",
+    "compressible": false,
+    "extensions": ["jar","war","ear"]
+  },
+  "application/java-serialized-object": {
+    "source": "apache",
+    "compressible": false,
+    "extensions": ["ser"]
+  },
+  "application/java-vm": {
+    "source": "apache",
+    "compressible": false,
+    "extensions": ["class"]
+  },
+  "application/javascript": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true,
+    "extensions": ["js","mjs"]
+  },
+  "application/jf2feed+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/jose": {
+    "source": "iana"
+  },
+  "application/jose+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/jrd+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/jscalendar+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/json": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true,
+    "extensions": ["json","map"]
+  },
+  "application/json-patch+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/json-seq": {
+    "source": "iana"
+  },
+  "application/json5": {
+    "extensions": ["json5"]
+  },
+  "application/jsonml+json": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["jsonml"]
+  },
+  "application/jwk+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/jwk-set+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/jwt": {
+    "source": "iana"
+  },
+  "application/kpml-request+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/kpml-response+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/ld+json": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["jsonld"]
+  },
+  "application/lgr+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["lgr"]
+  },
+  "application/link-format": {
+    "source": "iana"
+  },
+  "application/load-control+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/lost+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["lostxml"]
+  },
+  "application/lostsync+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/lpf+zip": {
+    "source": "iana",
+    "compressible": false
+  },
+  "application/lxf": {
+    "source": "iana"
+  },
+  "application/mac-binhex40": {
+    "source": "iana",
+    "extensions": ["hqx"]
+  },
+  "application/mac-compactpro": {
+    "source": "apache",
+    "extensions": ["cpt"]
+  },
+  "application/macwriteii": {
+    "source": "iana"
+  },
+  "application/mads+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mads"]
+  },
+  "application/manifest+json": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true,
+    "extensions": ["webmanifest"]
+  },
+  "application/marc": {
+    "source": "iana",
+    "extensions": ["mrc"]
+  },
+  "application/marcxml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mrcx"]
+  },
+  "application/mathematica": {
+    "source": "iana",
+    "extensions": ["ma","nb","mb"]
+  },
+  "application/mathml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mathml"]
+  },
+  "application/mathml-content+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mathml-presentation+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-associated-procedure-description+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-deregister+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-envelope+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-msk+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-msk-response+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-protection-description+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-reception-report+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-register+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-register-response+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-schedule+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbms-user-service-description+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mbox": {
+    "source": "iana",
+    "extensions": ["mbox"]
+  },
+  "application/media-policy-dataset+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mpf"]
+  },
+  "application/media_control+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mediaservercontrol+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mscml"]
+  },
+  "application/merge-patch+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/metalink+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["metalink"]
+  },
+  "application/metalink4+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["meta4"]
+  },
+  "application/mets+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mets"]
+  },
+  "application/mf4": {
+    "source": "iana"
+  },
+  "application/mikey": {
+    "source": "iana"
+  },
+  "application/mipc": {
+    "source": "iana"
+  },
+  "application/missing-blocks+cbor-seq": {
+    "source": "iana"
+  },
+  "application/mmt-aei+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["maei"]
+  },
+  "application/mmt-usd+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["musd"]
+  },
+  "application/mods+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mods"]
+  },
+  "application/moss-keys": {
+    "source": "iana"
+  },
+  "application/moss-signature": {
+    "source": "iana"
+  },
+  "application/mosskey-data": {
+    "source": "iana"
+  },
+  "application/mosskey-request": {
+    "source": "iana"
+  },
+  "application/mp21": {
+    "source": "iana",
+    "extensions": ["m21","mp21"]
+  },
+  "application/mp4": {
+    "source": "iana",
+    "extensions": ["mp4s","m4p"]
+  },
+  "application/mpeg4-generic": {
+    "source": "iana"
+  },
+  "application/mpeg4-iod": {
+    "source": "iana"
+  },
+  "application/mpeg4-iod-xmt": {
+    "source": "iana"
+  },
+  "application/mrb-consumer+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/mrb-publish+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/msc-ivr+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/msc-mixer+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/msword": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["doc","dot"]
+  },
+  "application/mud+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/multipart-core": {
+    "source": "iana"
+  },
+  "application/mxf": {
+    "source": "iana",
+    "extensions": ["mxf"]
+  },
+  "application/n-quads": {
+    "source": "iana",
+    "extensions": ["nq"]
+  },
+  "application/n-triples": {
+    "source": "iana",
+    "extensions": ["nt"]
+  },
+  "application/nasdata": {
+    "source": "iana"
+  },
+  "application/news-checkgroups": {
+    "source": "iana",
+    "charset": "US-ASCII"
+  },
+  "application/news-groupinfo": {
+    "source": "iana",
+    "charset": "US-ASCII"
+  },
+  "application/news-transmission": {
+    "source": "iana"
+  },
+  "application/nlsml+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/node": {
+    "source": "iana",
+    "extensions": ["cjs"]
+  },
+  "application/nss": {
+    "source": "iana"
+  },
+  "application/oauth-authz-req+jwt": {
+    "source": "iana"
+  },
+  "application/oblivious-dns-message": {
+    "source": "iana"
+  },
+  "application/ocsp-request": {
+    "source": "iana"
+  },
+  "application/ocsp-response": {
+    "source": "iana"
+  },
+  "application/octet-stream": {
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+    "compressible": false,
+    "extensions": ["bin","dms","lrf","mar","so","dist","distz","pkg","bpk","dump","elc","deploy","exe","dll","deb","dmg","iso","img","msi","msp","msm","buffer"]
+  },
+  "application/oda": {
+    "source": "iana",
+    "extensions": ["oda"]
+  },
+  "application/odm+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/odx": {
+    "source": "iana"
+  },
+  "application/oebps-package+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["opf"]
+  },
+  "application/ogg": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["ogx"]
+  },
+  "application/omdoc+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["omdoc"]
+  },
+  "application/onenote": {
+    "source": "apache",
+    "extensions": ["onetoc","onetoc2","onetmp","onepkg"]
+  },
+  "application/opc-nodeset+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/oscore": {
+    "source": "iana"
+  },
+  "application/oxps": {
+    "source": "iana",
+    "extensions": ["oxps"]
+  },
+  "application/p21": {
+    "source": "iana"
+  },
+  "application/p21+zip": {
+    "source": "iana",
+    "compressible": false
+  },
+  "application/p2p-overlay+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["relo"]
+  },
+  "application/parityfec": {
+    "source": "iana"
+  },
+  "application/passport": {
+    "source": "iana"
+  },
+  "application/patch-ops-error+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["xer"]
+  },
+  "application/pdf": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["pdf"]
+  },
+  "application/pdx": {
+    "source": "iana"
+  },
+  "application/pem-certificate-chain": {
+    "source": "iana"
+  },
+  "application/pgp-encrypted": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["pgp"]
+  },
+  "application/pgp-keys": {
+    "source": "iana",
+    "extensions": ["asc"]
+  },
+  "application/pgp-signature": {
+    "source": "iana",
+    "extensions": ["asc","sig"]
+  },
+  "application/pics-rules": {
+    "source": "apache",
+    "extensions": ["prf"]
+  },
+  "application/pidf+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/pidf-diff+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/pkcs10": {
+    "source": "iana",
+    "extensions": ["p10"]
+  },
+  "application/pkcs12": {
+    "source": "iana"
+  },
+  "application/pkcs7-mime": {
+    "source": "iana",
+    "extensions": ["p7m","p7c"]
+  },
+  "application/pkcs7-signature": {
+    "source": "iana",
+    "extensions": ["p7s"]
+  },
+  "application/pkcs8": {
+    "source": "iana",
+    "extensions": ["p8"]
+  },
+  "application/pkcs8-encrypted": {
+    "source": "iana"
+  },
+  "application/pkix-attr-cert": {
+    "source": "iana",
+    "extensions": ["ac"]
+  },
+  "application/pkix-cert": {
+    "source": "iana",
+    "extensions": ["cer"]
+  },
+  "application/pkix-crl": {
+    "source": "iana",
+    "extensions": ["crl"]
+  },
+  "application/pkix-pkipath": {
+    "source": "iana",
+    "extensions": ["pkipath"]
+  },
+  "application/pkixcmp": {
+    "source": "iana",
+    "extensions": ["pki"]
+  },
+  "application/pls+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["pls"]
+  },
+  "application/poc-settings+xml": {
+    "source": "iana",
+    "charset": "UTF-8",
+    "compressible": true
+  },
+  "application/postscript": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["ai","eps","ps"]
+  },
+  "application/ppsp-tracker+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/problem+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/problem+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/provenance+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["provx"]
+  },
+  "application/prs.alvestrand.titrax-sheet": {
+    "source": "iana"
+  },
+  "application/prs.cww": {
+    "source": "iana",
+    "extensions": ["cww"]
+  },
+  "application/prs.cyn": {
+    "source": "iana",
+    "charset": "7-BIT"
+  },
+  "application/prs.hpub+zip": {
+    "source": "iana",
+    "compressible": false
+  },
+  "application/prs.nprend": {
+    "source": "iana"
+  },
+  "application/prs.plucker": {
+    "source": "iana"
+  },
+  "application/prs.rdf-xml-crypt": {
+    "source": "iana"
+  },
+  "application/prs.xsf+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/pskc+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["pskcxml"]
+  },
+  "application/pvd+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/qsig": {
+    "source": "iana"
+  },
+  "application/raml+yaml": {
+    "compressible": true,
+    "extensions": ["raml"]
+  },
+  "application/raptorfec": {
+    "source": "iana"
+  },
+  "application/rdap+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/rdf+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["rdf","owl"]
+  },
+  "application/reginfo+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["rif"]
+  },
+  "application/relax-ng-compact-syntax": {
+    "source": "iana",
+    "extensions": ["rnc"]
+  },
+  "application/remote-printing": {
+    "source": "iana"
+  },
+  "application/reputon+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/resource-lists+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["rl"]
+  },
+  "application/resource-lists-diff+xml": {
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+    "compressible": true,
+    "extensions": ["rld"]
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+  "application/rfc+xml": {
+    "source": "iana",
+    "compressible": true
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+  "application/riscos": {
+    "source": "iana"
+  },
+  "application/rlmi+xml": {
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+    "compressible": true
+  },
+  "application/rls-services+xml": {
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+    "compressible": true,
+    "extensions": ["rs"]
+  },
+  "application/route-apd+xml": {
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+    "compressible": true,
+    "extensions": ["rapd"]
+  },
+  "application/route-s-tsid+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["sls"]
+  },
+  "application/route-usd+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["rusd"]
+  },
+  "application/rpki-ghostbusters": {
+    "source": "iana",
+    "extensions": ["gbr"]
+  },
+  "application/rpki-manifest": {
+    "source": "iana",
+    "extensions": ["mft"]
+  },
+  "application/rpki-publication": {
+    "source": "iana"
+  },
+  "application/rpki-roa": {
+    "source": "iana",
+    "extensions": ["roa"]
+  },
+  "application/rpki-updown": {
+    "source": "iana"
+  },
+  "application/rsd+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["rsd"]
+  },
+  "application/rss+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["rss"]
+  },
+  "application/rtf": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["rtf"]
+  },
+  "application/rtploopback": {
+    "source": "iana"
+  },
+  "application/rtx": {
+    "source": "iana"
+  },
+  "application/samlassertion+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/samlmetadata+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/sarif+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/sarif-external-properties+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/sbe": {
+    "source": "iana"
+  },
+  "application/sbml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["sbml"]
+  },
+  "application/scaip+xml": {
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+    "compressible": true
+  },
+  "application/scim+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/scvp-cv-request": {
+    "source": "iana",
+    "extensions": ["scq"]
+  },
+  "application/scvp-cv-response": {
+    "source": "iana",
+    "extensions": ["scs"]
+  },
+  "application/scvp-vp-request": {
+    "source": "iana",
+    "extensions": ["spq"]
+  },
+  "application/scvp-vp-response": {
+    "source": "iana",
+    "extensions": ["spp"]
+  },
+  "application/sdp": {
+    "source": "iana",
+    "extensions": ["sdp"]
+  },
+  "application/secevent+jwt": {
+    "source": "iana"
+  },
+  "application/senml+cbor": {
+    "source": "iana"
+  },
+  "application/senml+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/senml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["senmlx"]
+  },
+  "application/senml-etch+cbor": {
+    "source": "iana"
+  },
+  "application/senml-etch+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/senml-exi": {
+    "source": "iana"
+  },
+  "application/sensml+cbor": {
+    "source": "iana"
+  },
+  "application/sensml+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/sensml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["sensmlx"]
+  },
+  "application/sensml-exi": {
+    "source": "iana"
+  },
+  "application/sep+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/sep-exi": {
+    "source": "iana"
+  },
+  "application/session-info": {
+    "source": "iana"
+  },
+  "application/set-payment": {
+    "source": "iana"
+  },
+  "application/set-payment-initiation": {
+    "source": "iana",
+    "extensions": ["setpay"]
+  },
+  "application/set-registration": {
+    "source": "iana"
+  },
+  "application/set-registration-initiation": {
+    "source": "iana",
+    "extensions": ["setreg"]
+  },
+  "application/sgml": {
+    "source": "iana"
+  },
+  "application/sgml-open-catalog": {
+    "source": "iana"
+  },
+  "application/shf+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["shf"]
+  },
+  "application/sieve": {
+    "source": "iana",
+    "extensions": ["siv","sieve"]
+  },
+  "application/simple-filter+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/simple-message-summary": {
+    "source": "iana"
+  },
+  "application/simplesymbolcontainer": {
+    "source": "iana"
+  },
+  "application/sipc": {
+    "source": "iana"
+  },
+  "application/slate": {
+    "source": "iana"
+  },
+  "application/smil": {
+    "source": "iana"
+  },
+  "application/smil+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["smi","smil"]
+  },
+  "application/smpte336m": {
+    "source": "iana"
+  },
+  "application/soap+fastinfoset": {
+    "source": "iana"
+  },
+  "application/soap+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/sparql-query": {
+    "source": "iana",
+    "extensions": ["rq"]
+  },
+  "application/sparql-results+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["srx"]
+  },
+  "application/spdx+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/spirits-event+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/sql": {
+    "source": "iana"
+  },
+  "application/srgs": {
+    "source": "iana",
+    "extensions": ["gram"]
+  },
+  "application/srgs+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["grxml"]
+  },
+  "application/sru+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["sru"]
+  },
+  "application/ssdl+xml": {
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+    "compressible": true,
+    "extensions": ["ssdl"]
+  },
+  "application/ssml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["ssml"]
+  },
+  "application/stix+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/swid+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["swidtag"]
+  },
+  "application/tamp-apex-update": {
+    "source": "iana"
+  },
+  "application/tamp-apex-update-confirm": {
+    "source": "iana"
+  },
+  "application/tamp-community-update": {
+    "source": "iana"
+  },
+  "application/tamp-community-update-confirm": {
+    "source": "iana"
+  },
+  "application/tamp-error": {
+    "source": "iana"
+  },
+  "application/tamp-sequence-adjust": {
+    "source": "iana"
+  },
+  "application/tamp-sequence-adjust-confirm": {
+    "source": "iana"
+  },
+  "application/tamp-status-query": {
+    "source": "iana"
+  },
+  "application/tamp-status-response": {
+    "source": "iana"
+  },
+  "application/tamp-update": {
+    "source": "iana"
+  },
+  "application/tamp-update-confirm": {
+    "source": "iana"
+  },
+  "application/tar": {
+    "compressible": true
+  },
+  "application/taxii+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/td+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/tei+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["tei","teicorpus"]
+  },
+  "application/tetra_isi": {
+    "source": "iana"
+  },
+  "application/thraud+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["tfi"]
+  },
+  "application/timestamp-query": {
+    "source": "iana"
+  },
+  "application/timestamp-reply": {
+    "source": "iana"
+  },
+  "application/timestamped-data": {
+    "source": "iana",
+    "extensions": ["tsd"]
+  },
+  "application/tlsrpt+gzip": {
+    "source": "iana"
+  },
+  "application/tlsrpt+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/tnauthlist": {
+    "source": "iana"
+  },
+  "application/token-introspection+jwt": {
+    "source": "iana"
+  },
+  "application/toml": {
+    "compressible": true,
+    "extensions": ["toml"]
+  },
+  "application/trickle-ice-sdpfrag": {
+    "source": "iana"
+  },
+  "application/trig": {
+    "source": "iana",
+    "extensions": ["trig"]
+  },
+  "application/ttml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["ttml"]
+  },
+  "application/tve-trigger": {
+    "source": "iana"
+  },
+  "application/tzif": {
+    "source": "iana"
+  },
+  "application/tzif-leap": {
+    "source": "iana"
+  },
+  "application/ubjson": {
+    "compressible": false,
+    "extensions": ["ubj"]
+  },
+  "application/ulpfec": {
+    "source": "iana"
+  },
+  "application/urc-grpsheet+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/urc-ressheet+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["rsheet"]
+  },
+  "application/urc-targetdesc+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["td"]
+  },
+  "application/urc-uisocketdesc+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vcard+json": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vcard+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vemmi": {
+    "source": "iana"
+  },
+  "application/vividence.scriptfile": {
+    "source": "apache"
+  },
+  "application/vnd.1000minds.decision-model+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["1km"]
+  },
+  "application/vnd.3gpp-prose+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp-prose-pc3ch+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp-v2x-local-service-information": {
+    "source": "iana"
+  },
+  "application/vnd.3gpp.5gnas": {
+    "source": "iana"
+  },
+  "application/vnd.3gpp.access-transfer-events+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp.bsf+xml": {
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+    "compressible": true
+  },
+  "application/vnd.3gpp.gmop+xml": {
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+    "compressible": true
+  },
+  "application/vnd.3gpp.gtpc": {
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+  },
+  "application/vnd.3gpp.interworking-data": {
+    "source": "iana"
+  },
+  "application/vnd.3gpp.lpp": {
+    "source": "iana"
+  },
+  "application/vnd.3gpp.mc-signalling-ear": {
+    "source": "iana"
+  },
+  "application/vnd.3gpp.mcdata-affiliation-command+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp.mcdata-info+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp.mcdata-payload": {
+    "source": "iana"
+  },
+  "application/vnd.3gpp.mcdata-service-config+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp.mcdata-signalling": {
+    "source": "iana"
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+  "application/vnd.3gpp.mcdata-ue-config+xml": {
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+    "compressible": true
+  },
+  "application/vnd.3gpp.mcdata-user-profile+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp.mcptt-affiliation-command+xml": {
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+    "compressible": true
+  },
+  "application/vnd.3gpp.mcptt-floor-request+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp.mcptt-info+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp.mcptt-location-info+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp.mcptt-mbms-usage-info+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/vnd.3gpp.mcptt-service-config+xml": {
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+    "compressible": true
+  },
+  "application/vnd.3gpp.mcptt-signed+xml": {
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+    "compressible": true
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+  "application/vnd.3gpp.mcptt-ue-config+xml": {
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+    "compressible": true
+  },
+  "application/vnd.3gpp.mcptt-ue-init-config+xml": {
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+    "compressible": true
+  },
+  "application/vnd.3gpp.mcptt-user-profile+xml": {
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+    "compressible": true
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+  "application/vnd.3gpp.mcvideo-affiliation-command+xml": {
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+    "compressible": true
+  },
+  "application/vnd.3gpp.mcvideo-affiliation-info+xml": {
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+    "compressible": true
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+    "extensions": ["hlp"]
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+    "extensions": ["7z"]
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+    "extensions": ["abw"]
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+    "extensions": ["ace"]
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+    "extensions": ["dmg"]
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+    "extensions": ["arj"]
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+    "extensions": ["aab","x32","u32","vox"]
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+    "extensions": ["aam"]
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+    "extensions": ["aas"]
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+    "extensions": ["bcpio"]
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+    "extensions": ["bdoc"]
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+    "extensions": ["torrent"]
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+    "extensions": ["cbr","cba","cbt","cbz","cb7"]
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+    "extensions": ["vcd"]
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+    "extensions": ["cfs"]
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+    "extensions": ["chat"]
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+    "extensions": ["pgn"]
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+    "extensions": ["cco"]
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+    "source": "apache"
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+    "extensions": ["nsc"]
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+    "extensions": ["cpio"]
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+    "extensions": ["csh"]
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+    "extensions": ["deb","udeb"]
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+    "extensions": ["dgc"]
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+    "extensions": ["wad"]
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+    "extensions": ["ncx"]
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+    "extensions": ["dtb"]
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+    "extensions": ["res"]
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+    "extensions": ["dvi"]
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+    "extensions": ["evy"]
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+    "extensions": ["eva"]
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+    "extensions": ["gsf"]
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+    "extensions": ["psf"]
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+    "extensions": ["pcf"]
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+    "extensions": ["snf"]
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+  "application/x-font-sunos-news": {
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+    "source": "apache",
+    "extensions": ["pfa","pfb","pfm","afm"]
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+  "application/x-font-vfont": {
+    "source": "apache"
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+  "application/x-freearc": {
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+    "extensions": ["arc"]
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+    "extensions": ["spl"]
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+    "extensions": ["gca"]
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+    "extensions": ["ulx"]
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+    "extensions": ["gnumeric"]
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+    "extensions": ["gramps"]
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+    "extensions": ["gtar"]
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+    "extensions": ["php"]
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+  "application/x-install-instructions": {
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+    "extensions": ["install"]
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+    "extensions": ["iso"]
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+  "application/x-iwork-pages-sffpages": {
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+    "extensions": ["jardiff"]
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+    "compressible": false,
+    "extensions": ["jnlp"]
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+  "application/x-javascript": {
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+  "application/x-keepass2": {
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+    "compressible": false,
+    "extensions": ["latex"]
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+  "application/x-lua-bytecode": {
+    "extensions": ["luac"]
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+  "application/x-lzh-compressed": {
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+    "extensions": ["lzh","lha"]
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+  "application/x-makeself": {
+    "source": "nginx",
+    "extensions": ["run"]
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+  "application/x-mie": {
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+    "extensions": ["mie"]
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+  "application/x-mobipocket-ebook": {
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+    "extensions": ["prc","mobi"]
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+  "application/x-mpegurl": {
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+    "extensions": ["application"]
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+  "application/x-ms-shortcut": {
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+    "extensions": ["lnk"]
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+    "extensions": ["wmd"]
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+    "extensions": ["wmz"]
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+  "application/x-ms-xbap": {
+    "source": "apache",
+    "extensions": ["xbap"]
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+  "application/x-msaccess": {
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+    "extensions": ["mdb"]
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+  "application/x-msbinder": {
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+    "extensions": ["obd"]
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+  "application/x-mscardfile": {
+    "source": "apache",
+    "extensions": ["crd"]
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+  "application/x-msclip": {
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+    "extensions": ["clp"]
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+  "application/x-msdos-program": {
+    "extensions": ["exe"]
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+  "application/x-msdownload": {
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+    "extensions": ["exe","dll","com","bat","msi"]
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+  "application/x-msmediaview": {
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+    "extensions": ["mvb","m13","m14"]
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+  "application/x-msmetafile": {
+    "source": "apache",
+    "extensions": ["wmf","wmz","emf","emz"]
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+  "application/x-msmoney": {
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+    "extensions": ["mny"]
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+  "application/x-mspublisher": {
+    "source": "apache",
+    "extensions": ["pub"]
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+    "extensions": ["scd"]
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+  "application/x-msterminal": {
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+    "extensions": ["trm"]
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+  "application/x-mswrite": {
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+    "extensions": ["wri"]
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+  "application/x-netcdf": {
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+    "extensions": ["nc","cdf"]
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+  "application/x-ns-proxy-autoconfig": {
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+    "extensions": ["pac"]
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+  "application/x-nzb": {
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+    "extensions": ["nzb"]
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+  "application/x-perl": {
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+    "extensions": ["pl","pm"]
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+  "application/x-pilot": {
+    "source": "nginx",
+    "extensions": ["prc","pdb"]
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+  "application/x-pkcs12": {
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+    "compressible": false,
+    "extensions": ["p12","pfx"]
+  },
+  "application/x-pkcs7-certificates": {
+    "source": "apache",
+    "extensions": ["p7b","spc"]
+  },
+  "application/x-pkcs7-certreqresp": {
+    "source": "apache",
+    "extensions": ["p7r"]
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+  "application/x-pki-message": {
+    "source": "iana"
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+  "application/x-rar-compressed": {
+    "source": "apache",
+    "compressible": false,
+    "extensions": ["rar"]
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+  "application/x-redhat-package-manager": {
+    "source": "nginx",
+    "extensions": ["rpm"]
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+  "application/x-research-info-systems": {
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+    "extensions": ["ris"]
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+  "application/x-sea": {
+    "source": "nginx",
+    "extensions": ["sea"]
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+  "application/x-sh": {
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+    "compressible": true,
+    "extensions": ["sh"]
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+  "application/x-shar": {
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+    "extensions": ["shar"]
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+  "application/x-shockwave-flash": {
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+    "compressible": false,
+    "extensions": ["swf"]
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+  "application/x-silverlight-app": {
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+    "extensions": ["xap"]
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+    "extensions": ["sql"]
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+    "compressible": false,
+    "extensions": ["sit"]
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+    "extensions": ["sitx"]
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+    "extensions": ["srt"]
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+    "extensions": ["sv4cpio"]
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+    "extensions": ["sv4crc"]
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+    "extensions": ["t3"]
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+    "extensions": ["gam"]
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+    "compressible": true,
+    "extensions": ["tar"]
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+    "extensions": ["tcl","tk"]
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+    "source": "apache",
+    "extensions": ["tex"]
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+    "source": "apache",
+    "extensions": ["tfm"]
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+    "source": "apache",
+    "extensions": ["texinfo","texi"]
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+    "extensions": ["obj"]
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+    "extensions": ["ustar"]
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+    "extensions": ["hdd"]
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+    "extensions": ["ova"]
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+    "extensions": ["ovf"]
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+    "extensions": ["vbox"]
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+    "extensions": ["vbox-extpack"]
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+    "extensions": ["vdi"]
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+    "extensions": ["vhd"]
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+    "extensions": ["vmdk"]
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+  "application/x-wais-source": {
+    "source": "apache",
+    "extensions": ["src"]
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+  "application/x-web-app-manifest+json": {
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+    "extensions": ["webapp"]
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+  "application/x-www-form-urlencoded": {
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+    "compressible": true
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+  "application/x-x509-ca-cert": {
+    "source": "iana",
+    "extensions": ["der","crt","pem"]
+  },
+  "application/x-x509-ca-ra-cert": {
+    "source": "iana"
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+  "application/x-x509-next-ca-cert": {
+    "source": "iana"
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+  "application/x-xfig": {
+    "source": "apache",
+    "extensions": ["fig"]
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+  "application/x-xliff+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["xlf"]
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+  "application/x-xpinstall": {
+    "source": "apache",
+    "compressible": false,
+    "extensions": ["xpi"]
+  },
+  "application/x-xz": {
+    "source": "apache",
+    "extensions": ["xz"]
+  },
+  "application/x-zmachine": {
+    "source": "apache",
+    "extensions": ["z1","z2","z3","z4","z5","z6","z7","z8"]
+  },
+  "application/x400-bp": {
+    "source": "iana"
+  },
+  "application/xacml+xml": {
+    "source": "iana",
+    "compressible": true
+  },
+  "application/xaml+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["xaml"]
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+  "application/xcap-att+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["xav"]
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+  "application/xcap-caps+xml": {
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+    "compressible": true,
+    "extensions": ["xca"]
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+    "compressible": true,
+    "extensions": ["xdf"]
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+  "application/xcap-el+xml": {
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+    "compressible": true,
+    "extensions": ["xel"]
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+  "application/xcap-error+xml": {
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+    "compressible": true
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+  "application/xcap-ns+xml": {
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+    "compressible": true,
+    "extensions": ["xns"]
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+  "application/xcon-conference-info+xml": {
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+    "compressible": true
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+  "application/xcon-conference-info-diff+xml": {
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+    "compressible": true
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+    "compressible": true,
+    "extensions": ["xenc"]
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+  "application/xhtml+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["xhtml","xht"]
+  },
+  "application/xhtml-voice+xml": {
+    "source": "apache",
+    "compressible": true
+  },
+  "application/xliff+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["xlf"]
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+  "application/xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["xml","xsl","xsd","rng"]
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+  "application/xml-dtd": {
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+    "compressible": true,
+    "extensions": ["dtd"]
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+  "application/xml-external-parsed-entity": {
+    "source": "iana"
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+  "application/xml-patch+xml": {
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+  "application/xmpp+xml": {
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+    "compressible": true
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+  "application/xop+xml": {
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+    "compressible": true,
+    "extensions": ["xop"]
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+  "application/xproc+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["xpl"]
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+  "application/xslt+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["xsl","xslt"]
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+  "application/xspf+xml": {
+    "source": "apache",
+    "compressible": true,
+    "extensions": ["xspf"]
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+  "application/xv+xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["mxml","xhvml","xvml","xvm"]
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+  "application/yang": {
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+    "extensions": ["yang"]
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+  "application/yang-data+json": {
+    "source": "iana",
+    "compressible": true
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+  "application/yang-data+xml": {
+    "source": "iana",
+    "compressible": true
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+  "application/yang-patch+json": {
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+    "compressible": true
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+  "application/yang-patch+xml": {
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+    "compressible": true
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+    "compressible": true,
+    "extensions": ["yin"]
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+    "compressible": false,
+    "extensions": ["zip"]
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+  "application/zlib": {
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+  "application/zstd": {
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+  "audio/1d-interleaved-parityfec": {
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+  "audio/32kadpcm": {
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+  "audio/3gpp": {
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+    "compressible": false,
+    "extensions": ["3gpp"]
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+  "audio/3gpp2": {
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+  "audio/aac": {
+    "source": "iana"
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+  "audio/ac3": {
+    "source": "iana"
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+  "audio/adpcm": {
+    "source": "apache",
+    "extensions": ["adp"]
+  },
+  "audio/amr": {
+    "source": "iana",
+    "extensions": ["amr"]
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+  "audio/amr-wb": {
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+  "audio/atrac-x": {
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+    "extensions": ["java"]
+  },
+  "text/x-jquery-tmpl": {
+    "compressible": true
+  },
+  "text/x-lua": {
+    "extensions": ["lua"]
+  },
+  "text/x-markdown": {
+    "compressible": true,
+    "extensions": ["mkd"]
+  },
+  "text/x-nfo": {
+    "source": "apache",
+    "extensions": ["nfo"]
+  },
+  "text/x-opml": {
+    "source": "apache",
+    "extensions": ["opml"]
+  },
+  "text/x-org": {
+    "compressible": true,
+    "extensions": ["org"]
+  },
+  "text/x-pascal": {
+    "source": "apache",
+    "extensions": ["p","pas"]
+  },
+  "text/x-processing": {
+    "compressible": true,
+    "extensions": ["pde"]
+  },
+  "text/x-sass": {
+    "extensions": ["sass"]
+  },
+  "text/x-scss": {
+    "extensions": ["scss"]
+  },
+  "text/x-setext": {
+    "source": "apache",
+    "extensions": ["etx"]
+  },
+  "text/x-sfv": {
+    "source": "apache",
+    "extensions": ["sfv"]
+  },
+  "text/x-suse-ymp": {
+    "compressible": true,
+    "extensions": ["ymp"]
+  },
+  "text/x-uuencode": {
+    "source": "apache",
+    "extensions": ["uu"]
+  },
+  "text/x-vcalendar": {
+    "source": "apache",
+    "extensions": ["vcs"]
+  },
+  "text/x-vcard": {
+    "source": "apache",
+    "extensions": ["vcf"]
+  },
+  "text/xml": {
+    "source": "iana",
+    "compressible": true,
+    "extensions": ["xml"]
+  },
+  "text/xml-external-parsed-entity": {
+    "source": "iana"
+  },
+  "text/yaml": {
+    "compressible": true,
+    "extensions": ["yaml","yml"]
+  },
+  "video/1d-interleaved-parityfec": {
+    "source": "iana"
+  },
+  "video/3gpp": {
+    "source": "iana",
+    "extensions": ["3gp","3gpp"]
+  },
+  "video/3gpp-tt": {
+    "source": "iana"
+  },
+  "video/3gpp2": {
+    "source": "iana",
+    "extensions": ["3g2"]
+  },
+  "video/av1": {
+    "source": "iana"
+  },
+  "video/bmpeg": {
+    "source": "iana"
+  },
+  "video/bt656": {
+    "source": "iana"
+  },
+  "video/celb": {
+    "source": "iana"
+  },
+  "video/dv": {
+    "source": "iana"
+  },
+  "video/encaprtp": {
+    "source": "iana"
+  },
+  "video/ffv1": {
+    "source": "iana"
+  },
+  "video/flexfec": {
+    "source": "iana"
+  },
+  "video/h261": {
+    "source": "iana",
+    "extensions": ["h261"]
+  },
+  "video/h263": {
+    "source": "iana",
+    "extensions": ["h263"]
+  },
+  "video/h263-1998": {
+    "source": "iana"
+  },
+  "video/h263-2000": {
+    "source": "iana"
+  },
+  "video/h264": {
+    "source": "iana",
+    "extensions": ["h264"]
+  },
+  "video/h264-rcdo": {
+    "source": "iana"
+  },
+  "video/h264-svc": {
+    "source": "iana"
+  },
+  "video/h265": {
+    "source": "iana"
+  },
+  "video/iso.segment": {
+    "source": "iana",
+    "extensions": ["m4s"]
+  },
+  "video/jpeg": {
+    "source": "iana",
+    "extensions": ["jpgv"]
+  },
+  "video/jpeg2000": {
+    "source": "iana"
+  },
+  "video/jpm": {
+    "source": "apache",
+    "extensions": ["jpm","jpgm"]
+  },
+  "video/jxsv": {
+    "source": "iana"
+  },
+  "video/mj2": {
+    "source": "iana",
+    "extensions": ["mj2","mjp2"]
+  },
+  "video/mp1s": {
+    "source": "iana"
+  },
+  "video/mp2p": {
+    "source": "iana"
+  },
+  "video/mp2t": {
+    "source": "iana",
+    "extensions": ["ts"]
+  },
+  "video/mp4": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["mp4","mp4v","mpg4"]
+  },
+  "video/mp4v-es": {
+    "source": "iana"
+  },
+  "video/mpeg": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["mpeg","mpg","mpe","m1v","m2v"]
+  },
+  "video/mpeg4-generic": {
+    "source": "iana"
+  },
+  "video/mpv": {
+    "source": "iana"
+  },
+  "video/nv": {
+    "source": "iana"
+  },
+  "video/ogg": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["ogv"]
+  },
+  "video/parityfec": {
+    "source": "iana"
+  },
+  "video/pointer": {
+    "source": "iana"
+  },
+  "video/quicktime": {
+    "source": "iana",
+    "compressible": false,
+    "extensions": ["qt","mov"]
+  },
+  "video/raptorfec": {
+    "source": "iana"
+  },
+  "video/raw": {
+    "source": "iana"
+  },
+  "video/rtp-enc-aescm128": {
+    "source": "iana"
+  },
+  "video/rtploopback": {
+    "source": "iana"
+  },
+  "video/rtx": {
+    "source": "iana"
+  },
+  "video/scip": {
+    "source": "iana"
+  },
+  "video/smpte291": {
+    "source": "iana"
+  },
+  "video/smpte292m": {
+    "source": "iana"
+  },
+  "video/ulpfec": {
+    "source": "iana"
+  },
+  "video/vc1": {
+    "source": "iana"
+  },
+  "video/vc2": {
+    "source": "iana"
+  },
+  "video/vnd.cctv": {
+    "source": "iana"
+  },
+  "video/vnd.dece.hd": {
+    "source": "iana",
+    "extensions": ["uvh","uvvh"]
+  },
+  "video/vnd.dece.mobile": {
+    "source": "iana",
+    "extensions": ["uvm","uvvm"]
+  },
+  "video/vnd.dece.mp4": {
+    "source": "iana"
+  },
+  "video/vnd.dece.pd": {
+    "source": "iana",
+    "extensions": ["uvp","uvvp"]
+  },
+  "video/vnd.dece.sd": {
+    "source": "iana",
+    "extensions": ["uvs","uvvs"]
+  },
+  "video/vnd.dece.video": {
+    "source": "iana",
+    "extensions": ["uvv","uvvv"]
+  },
+  "video/vnd.directv.mpeg": {
+    "source": "iana"
+  },
+  "video/vnd.directv.mpeg-tts": {
+    "source": "iana"
+  },
+  "video/vnd.dlna.mpeg-tts": {
+    "source": "iana"
+  },
+  "video/vnd.dvb.file": {
+    "source": "iana",
+    "extensions": ["dvb"]
+  },
+  "video/vnd.fvt": {
+    "source": "iana",
+    "extensions": ["fvt"]
+  },
+  "video/vnd.hns.video": {
+    "source": "iana"
+  },
+  "video/vnd.iptvforum.1dparityfec-1010": {
+    "source": "iana"
+  },
+  "video/vnd.iptvforum.1dparityfec-2005": {
+    "source": "iana"
+  },
+  "video/vnd.iptvforum.2dparityfec-1010": {
+    "source": "iana"
+  },
+  "video/vnd.iptvforum.2dparityfec-2005": {
+    "source": "iana"
+  },
+  "video/vnd.iptvforum.ttsavc": {
+    "source": "iana"
+  },
+  "video/vnd.iptvforum.ttsmpeg2": {
+    "source": "iana"
+  },
+  "video/vnd.motorola.video": {
+    "source": "iana"
+  },
+  "video/vnd.motorola.videop": {
+    "source": "iana"
+  },
+  "video/vnd.mpegurl": {
+    "source": "iana",
+    "extensions": ["mxu","m4u"]
+  },
+  "video/vnd.ms-playready.media.pyv": {
+    "source": "iana",
+    "extensions": ["pyv"]
+  },
+  "video/vnd.nokia.interleaved-multimedia": {
+    "source": "iana"
+  },
+  "video/vnd.nokia.mp4vr": {
+    "source": "iana"
+  },
+  "video/vnd.nokia.videovoip": {
+    "source": "iana"
+  },
+  "video/vnd.objectvideo": {
+    "source": "iana"
+  },
+  "video/vnd.radgamettools.bink": {
+    "source": "iana"
+  },
+  "video/vnd.radgamettools.smacker": {
+    "source": "iana"
+  },
+  "video/vnd.sealed.mpeg1": {
+    "source": "iana"
+  },
+  "video/vnd.sealed.mpeg4": {
+    "source": "iana"
+  },
+  "video/vnd.sealed.swf": {
+    "source": "iana"
+  },
+  "video/vnd.sealedmedia.softseal.mov": {
+    "source": "iana"
+  },
+  "video/vnd.uvvu.mp4": {
+    "source": "iana",
+    "extensions": ["uvu","uvvu"]
+  },
+  "video/vnd.vivo": {
+    "source": "iana",
+    "extensions": ["viv"]
+  },
+  "video/vnd.youtube.yt": {
+    "source": "iana"
+  },
+  "video/vp8": {
+    "source": "iana"
+  },
+  "video/vp9": {
+    "source": "iana"
+  },
+  "video/webm": {
+    "source": "apache",
+    "compressible": false,
+    "extensions": ["webm"]
+  },
+  "video/x-f4v": {
+    "source": "apache",
+    "extensions": ["f4v"]
+  },
+  "video/x-fli": {
+    "source": "apache",
+    "extensions": ["fli"]
+  },
+  "video/x-flv": {
+    "source": "apache",
+    "compressible": false,
+    "extensions": ["flv"]
+  },
+  "video/x-m4v": {
+    "source": "apache",
+    "extensions": ["m4v"]
+  },
+  "video/x-matroska": {
+    "source": "apache",
+    "compressible": false,
+    "extensions": ["mkv","mk3d","mks"]
+  },
+  "video/x-mng": {
+    "source": "apache",
+    "extensions": ["mng"]
+  },
+  "video/x-ms-asf": {
+    "source": "apache",
+    "extensions": ["asf","asx"]
+  },
+  "video/x-ms-vob": {
+    "source": "apache",
+    "extensions": ["vob"]
+  },
+  "video/x-ms-wm": {
+    "source": "apache",
+    "extensions": ["wm"]
+  },
+  "video/x-ms-wmv": {
+    "source": "apache",
+    "compressible": false,
+    "extensions": ["wmv"]
+  },
+  "video/x-ms-wmx": {
+    "source": "apache",
+    "extensions": ["wmx"]
+  },
+  "video/x-ms-wvx": {
+    "source": "apache",
+    "extensions": ["wvx"]
+  },
+  "video/x-msvideo": {
+    "source": "apache",
+    "extensions": ["avi"]
+  },
+  "video/x-sgi-movie": {
+    "source": "apache",
+    "extensions": ["movie"]
+  },
+  "video/x-smv": {
+    "source": "apache",
+    "extensions": ["smv"]
+  },
+  "x-conference/x-cooltalk": {
+    "source": "apache",
+    "extensions": ["ice"]
+  },
+  "x-shader/x-fragment": {
+    "compressible": true
+  },
+  "x-shader/x-vertex": {
+    "compressible": true
+  }
+}
diff --git a/server/node_modules/mime-db/index.js b/server/node_modules/mime-db/index.js
new file mode 100644
index 0000000..ec2be30
--- /dev/null
+++ b/server/node_modules/mime-db/index.js
@@ -0,0 +1,12 @@
+/*!
+ * mime-db
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2015-2022 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+/**
+ * Module exports.
+ */
+
+module.exports = require('./db.json')
diff --git a/server/node_modules/mime-db/package.json b/server/node_modules/mime-db/package.json
new file mode 100644
index 0000000..32c14b8
--- /dev/null
+++ b/server/node_modules/mime-db/package.json
@@ -0,0 +1,60 @@
+{
+  "name": "mime-db",
+  "description": "Media Type Database",
+  "version": "1.52.0",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)",
+    "Robert Kieffer <robert@broofa.com> (http://github.com/broofa)"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "mime",
+    "db",
+    "type",
+    "types",
+    "database",
+    "charset",
+    "charsets"
+  ],
+  "repository": "jshttp/mime-db",
+  "devDependencies": {
+    "bluebird": "3.7.2",
+    "co": "4.6.0",
+    "cogent": "1.0.1",
+    "csv-parse": "4.16.3",
+    "eslint": "7.32.0",
+    "eslint-config-standard": "15.0.1",
+    "eslint-plugin-import": "2.25.4",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "5.1.1",
+    "eslint-plugin-standard": "4.1.0",
+    "gnode": "0.1.2",
+    "media-typer": "1.1.0",
+    "mocha": "9.2.1",
+    "nyc": "15.1.0",
+    "raw-body": "2.5.0",
+    "stream-to-array": "2.3.0"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "README.md",
+    "db.json",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "build": "node scripts/build",
+    "fetch": "node scripts/fetch-apache && gnode scripts/fetch-iana && node scripts/fetch-nginx",
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "update": "npm run fetch && npm run build",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  }
+}
diff --git a/server/node_modules/mime-types/HISTORY.md b/server/node_modules/mime-types/HISTORY.md
new file mode 100644
index 0000000..c5043b7
--- /dev/null
+++ b/server/node_modules/mime-types/HISTORY.md
@@ -0,0 +1,397 @@
+2.1.35 / 2022-03-12
+===================
+
+  * deps: mime-db@1.52.0
+    - Add extensions from IANA for more `image/*` types
+    - Add extension `.asc` to `application/pgp-keys`
+    - Add extensions to various XML types
+    - Add new upstream MIME types
+
+2.1.34 / 2021-11-08
+===================
+
+  * deps: mime-db@1.51.0
+    - Add new upstream MIME types
+
+2.1.33 / 2021-10-01
+===================
+
+  * deps: mime-db@1.50.0
+    - Add deprecated iWorks mime types and extensions
+    - Add new upstream MIME types
+
+2.1.32 / 2021-07-27
+===================
+
+  * deps: mime-db@1.49.0
+    - Add extension `.trig` to `application/trig`
+    - Add new upstream MIME types
+
+2.1.31 / 2021-06-01
+===================
+
+  * deps: mime-db@1.48.0
+    - Add extension `.mvt` to `application/vnd.mapbox-vector-tile`
+    - Add new upstream MIME types
+
+2.1.30 / 2021-04-02
+===================
+
+  * deps: mime-db@1.47.0
+    - Add extension `.amr` to `audio/amr`
+    - Remove ambigious extensions from IANA for `application/*+xml` types
+    - Update primary extension to `.es` for `application/ecmascript`
+
+2.1.29 / 2021-02-17
+===================
+
+  * deps: mime-db@1.46.0
+    - Add extension `.amr` to `audio/amr`
+    - Add extension `.m4s` to `video/iso.segment`
+    - Add extension `.opus` to `audio/ogg`
+    - Add new upstream MIME types
+
+2.1.28 / 2021-01-01
+===================
+
+  * deps: mime-db@1.45.0
+    - Add `application/ubjson` with extension `.ubj`
+    - Add `image/avif` with extension `.avif`
+    - Add `image/ktx2` with extension `.ktx2`
+    - Add extension `.dbf` to `application/vnd.dbf`
+    - Add extension `.rar` to `application/vnd.rar`
+    - Add extension `.td` to `application/urc-targetdesc+xml`
+    - Add new upstream MIME types
+    - Fix extension of `application/vnd.apple.keynote` to be `.key`
+
+2.1.27 / 2020-04-23
+===================
+
+  * deps: mime-db@1.44.0
+    - Add charsets from IANA
+    - Add extension `.cjs` to `application/node`
+    - Add new upstream MIME types
+
+2.1.26 / 2020-01-05
+===================
+
+  * deps: mime-db@1.43.0
+    - Add `application/x-keepass2` with extension `.kdbx`
+    - Add extension `.mxmf` to `audio/mobile-xmf`
+    - Add extensions from IANA for `application/*+xml` types
+    - Add new upstream MIME types
+
+2.1.25 / 2019-11-12
+===================
+
+  * deps: mime-db@1.42.0
+    - Add new upstream MIME types
+    - Add `application/toml` with extension `.toml`
+    - Add `image/vnd.ms-dds` with extension `.dds`
+
+2.1.24 / 2019-04-20
+===================
+
+  * deps: mime-db@1.40.0
+    - Add extensions from IANA for `model/*` types
+    - Add `text/mdx` with extension `.mdx`
+
+2.1.23 / 2019-04-17
+===================
+
+  * deps: mime-db@~1.39.0
+    - Add extensions `.siv` and `.sieve` to `application/sieve`
+    - Add new upstream MIME types
+
+2.1.22 / 2019-02-14
+===================
+
+  * deps: mime-db@~1.38.0
+    - Add extension `.nq` to `application/n-quads`
+    - Add extension `.nt` to `application/n-triples`
+    - Add new upstream MIME types
+
+2.1.21 / 2018-10-19
+===================
+
+  * deps: mime-db@~1.37.0
+    - Add extensions to HEIC image types
+    - Add new upstream MIME types
+
+2.1.20 / 2018-08-26
+===================
+
+  * deps: mime-db@~1.36.0
+    - Add Apple file extensions from IANA
+    - Add extensions from IANA for `image/*` types
+    - Add new upstream MIME types
+
+2.1.19 / 2018-07-17
+===================
+
+  * deps: mime-db@~1.35.0
+    - Add extension `.csl` to `application/vnd.citationstyles.style+xml`
+    - Add extension `.es` to `application/ecmascript`
+    - Add extension `.owl` to `application/rdf+xml`
+    - Add new upstream MIME types
+    - Add UTF-8 as default charset for `text/turtle`
+
+2.1.18 / 2018-02-16
+===================
+
+  * deps: mime-db@~1.33.0
+    - Add `application/raml+yaml` with extension `.raml`
+    - Add `application/wasm` with extension `.wasm`
+    - Add `text/shex` with extension `.shex`
+    - Add extensions for JPEG-2000 images
+    - Add extensions from IANA for `message/*` types
+    - Add new upstream MIME types
+    - Update font MIME types
+    - Update `text/hjson` to registered `application/hjson`
+
+2.1.17 / 2017-09-01
+===================
+
+  * deps: mime-db@~1.30.0
+    - Add `application/vnd.ms-outlook`
+    - Add `application/x-arj`
+    - Add extension `.mjs` to `application/javascript`
+    - Add glTF types and extensions
+    - Add new upstream MIME types
+    - Add `text/x-org`
+    - Add VirtualBox MIME types
+    - Fix `source` records for `video/*` types that are IANA
+    - Update `font/opentype` to registered `font/otf`
+
+2.1.16 / 2017-07-24
+===================
+
+  * deps: mime-db@~1.29.0
+    - Add `application/fido.trusted-apps+json`
+    - Add extension `.wadl` to `application/vnd.sun.wadl+xml`
+    - Add extension `.gz` to `application/gzip`
+    - Add new upstream MIME types
+    - Update extensions `.md` and `.markdown` to be `text/markdown`
+
+2.1.15 / 2017-03-23
+===================
+
+  * deps: mime-db@~1.27.0
+    - Add new mime types
+    - Add `image/apng`
+
+2.1.14 / 2017-01-14
+===================
+
+  * deps: mime-db@~1.26.0
+    - Add new mime types
+
+2.1.13 / 2016-11-18
+===================
+
+  * deps: mime-db@~1.25.0
+    - Add new mime types
+
+2.1.12 / 2016-09-18
+===================
+
+  * deps: mime-db@~1.24.0
+    - Add new mime types
+    - Add `audio/mp3`
+
+2.1.11 / 2016-05-01
+===================
+
+  * deps: mime-db@~1.23.0
+    - Add new mime types
+
+2.1.10 / 2016-02-15
+===================
+
+  * deps: mime-db@~1.22.0
+    - Add new mime types
+    - Fix extension of `application/dash+xml`
+    - Update primary extension for `audio/mp4`
+
+2.1.9 / 2016-01-06
+==================
+
+  * deps: mime-db@~1.21.0
+    - Add new mime types
+
+2.1.8 / 2015-11-30
+==================
+
+  * deps: mime-db@~1.20.0
+    - Add new mime types
+
+2.1.7 / 2015-09-20
+==================
+
+  * deps: mime-db@~1.19.0
+    - Add new mime types
+
+2.1.6 / 2015-09-03
+==================
+
+  * deps: mime-db@~1.18.0
+    - Add new mime types
+
+2.1.5 / 2015-08-20
+==================
+
+  * deps: mime-db@~1.17.0
+    - Add new mime types
+
+2.1.4 / 2015-07-30
+==================
+
+  * deps: mime-db@~1.16.0
+    - Add new mime types
+
+2.1.3 / 2015-07-13
+==================
+
+  * deps: mime-db@~1.15.0
+    - Add new mime types
+
+2.1.2 / 2015-06-25
+==================
+
+  * deps: mime-db@~1.14.0
+    - Add new mime types
+
+2.1.1 / 2015-06-08
+==================
+
+  * perf: fix deopt during mapping
+
+2.1.0 / 2015-06-07
+==================
+
+  * Fix incorrectly treating extension-less file name as extension
+    - i.e. `'path/to/json'` will no longer return `application/json`
+  * Fix `.charset(type)` to accept parameters
+  * Fix `.charset(type)` to match case-insensitive
+  * Improve generation of extension to MIME mapping
+  * Refactor internals for readability and no argument reassignment
+  * Prefer `application/*` MIME types from the same source
+  * Prefer any type over `application/octet-stream`
+  * deps: mime-db@~1.13.0
+    - Add nginx as a source
+    - Add new mime types
+
+2.0.14 / 2015-06-06
+===================
+
+  * deps: mime-db@~1.12.0
+    - Add new mime types
+
+2.0.13 / 2015-05-31
+===================
+
+  * deps: mime-db@~1.11.0
+    - Add new mime types
+
+2.0.12 / 2015-05-19
+===================
+
+  * deps: mime-db@~1.10.0
+    - Add new mime types
+
+2.0.11 / 2015-05-05
+===================
+
+  * deps: mime-db@~1.9.1
+    - Add new mime types
+
+2.0.10 / 2015-03-13
+===================
+
+  * deps: mime-db@~1.8.0
+    - Add new mime types
+
+2.0.9 / 2015-02-09
+==================
+
+  * deps: mime-db@~1.7.0
+    - Add new mime types
+    - Community extensions ownership transferred from `node-mime`
+
+2.0.8 / 2015-01-29
+==================
+
+  * deps: mime-db@~1.6.0
+    - Add new mime types
+
+2.0.7 / 2014-12-30
+==================
+
+  * deps: mime-db@~1.5.0
+    - Add new mime types
+    - Fix various invalid MIME type entries
+
+2.0.6 / 2014-12-30
+==================
+
+  * deps: mime-db@~1.4.0
+    - Add new mime types
+    - Fix various invalid MIME type entries
+    - Remove example template MIME types
+
+2.0.5 / 2014-12-29
+==================
+
+  * deps: mime-db@~1.3.1
+    - Fix missing extensions
+
+2.0.4 / 2014-12-10
+==================
+
+  * deps: mime-db@~1.3.0
+    - Add new mime types
+
+2.0.3 / 2014-11-09
+==================
+
+  * deps: mime-db@~1.2.0
+    - Add new mime types
+
+2.0.2 / 2014-09-28
+==================
+
+  * deps: mime-db@~1.1.0
+    - Add new mime types
+    - Update charsets
+
+2.0.1 / 2014-09-07
+==================
+
+  * Support Node.js 0.6
+
+2.0.0 / 2014-09-02
+==================
+
+  * Use `mime-db`
+  * Remove `.define()`
+
+1.0.2 / 2014-08-04
+==================
+
+  * Set charset=utf-8 for `text/javascript`
+
+1.0.1 / 2014-06-24
+==================
+
+  * Add `text/jsx` type
+
+1.0.0 / 2014-05-12
+==================
+
+  * Return `false` for unknown types
+  * Set charset=utf-8 for `application/json`
+
+0.1.0 / 2014-05-02
+==================
+
+  * Initial release
diff --git a/server/node_modules/mime-types/LICENSE b/server/node_modules/mime-types/LICENSE
new file mode 100644
index 0000000..0616607
--- /dev/null
+++ b/server/node_modules/mime-types/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2014 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/mime-types/README.md b/server/node_modules/mime-types/README.md
new file mode 100644
index 0000000..48d2fb4
--- /dev/null
+++ b/server/node_modules/mime-types/README.md
@@ -0,0 +1,113 @@
+# mime-types
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][ci-image]][ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+The ultimate javascript content-type utility.
+
+Similar to [the `mime@1.x` module](https://www.npmjs.com/package/mime), except:
+
+- __No fallbacks.__ Instead of naively returning the first available type,
+  `mime-types` simply returns `false`, so do
+  `var type = mime.lookup('unrecognized') || 'application/octet-stream'`.
+- No `new Mime()` business, so you could do `var lookup = require('mime-types').lookup`.
+- No `.define()` functionality
+- Bug fixes for `.lookup(path)`
+
+Otherwise, the API is compatible with `mime` 1.x.
+
+## Install
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install mime-types
+```
+
+## Adding Types
+
+All mime types are based on [mime-db](https://www.npmjs.com/package/mime-db),
+so open a PR there if you'd like to add mime types.
+
+## API
+
+```js
+var mime = require('mime-types')
+```
+
+All functions return `false` if input is invalid or not found.
+
+### mime.lookup(path)
+
+Lookup the content-type associated with a file.
+
+```js
+mime.lookup('json') // 'application/json'
+mime.lookup('.md') // 'text/markdown'
+mime.lookup('file.html') // 'text/html'
+mime.lookup('folder/file.js') // 'application/javascript'
+mime.lookup('folder/.htaccess') // false
+
+mime.lookup('cats') // false
+```
+
+### mime.contentType(type)
+
+Create a full content-type header given a content-type or extension.
+When given an extension, `mime.lookup` is used to get the matching
+content-type, otherwise the given content-type is used. Then if the
+content-type does not already have a `charset` parameter, `mime.charset`
+is used to get the default charset and add to the returned content-type.
+
+```js
+mime.contentType('markdown') // 'text/x-markdown; charset=utf-8'
+mime.contentType('file.json') // 'application/json; charset=utf-8'
+mime.contentType('text/html') // 'text/html; charset=utf-8'
+mime.contentType('text/html; charset=iso-8859-1') // 'text/html; charset=iso-8859-1'
+
+// from a full path
+mime.contentType(path.extname('/path/to/file.json')) // 'application/json; charset=utf-8'
+```
+
+### mime.extension(type)
+
+Get the default extension for a content-type.
+
+```js
+mime.extension('application/octet-stream') // 'bin'
+```
+
+### mime.charset(type)
+
+Lookup the implied default charset of a content-type.
+
+```js
+mime.charset('text/markdown') // 'UTF-8'
+```
+
+### var type = mime.types[extension]
+
+A map of content-types by extension.
+
+### [extensions...] = mime.extensions[type]
+
+A map of extensions by content-type.
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/jshttp/mime-types/master?label=ci
+[ci-url]: https://github.com/jshttp/mime-types/actions/workflows/ci.yml
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/mime-types/master
+[coveralls-url]: https://coveralls.io/r/jshttp/mime-types?branch=master
+[node-version-image]: https://badgen.net/npm/node/mime-types
+[node-version-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/mime-types
+[npm-url]: https://npmjs.org/package/mime-types
+[npm-version-image]: https://badgen.net/npm/v/mime-types
diff --git a/server/node_modules/mime-types/index.js b/server/node_modules/mime-types/index.js
new file mode 100644
index 0000000..b9f34d5
--- /dev/null
+++ b/server/node_modules/mime-types/index.js
@@ -0,0 +1,188 @@
+/*!
+ * mime-types
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var db = require('mime-db')
+var extname = require('path').extname
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var EXTRACT_TYPE_REGEXP = /^\s*([^;\s]*)(?:;|\s|$)/
+var TEXT_TYPE_REGEXP = /^text\//i
+
+/**
+ * Module exports.
+ * @public
+ */
+
+exports.charset = charset
+exports.charsets = { lookup: charset }
+exports.contentType = contentType
+exports.extension = extension
+exports.extensions = Object.create(null)
+exports.lookup = lookup
+exports.types = Object.create(null)
+
+// Populate the extensions/types maps
+populateMaps(exports.extensions, exports.types)
+
+/**
+ * Get the default charset for a MIME type.
+ *
+ * @param {string} type
+ * @return {boolean|string}
+ */
+
+function charset (type) {
+  if (!type || typeof type !== 'string') {
+    return false
+  }
+
+  // TODO: use media-typer
+  var match = EXTRACT_TYPE_REGEXP.exec(type)
+  var mime = match && db[match[1].toLowerCase()]
+
+  if (mime && mime.charset) {
+    return mime.charset
+  }
+
+  // default text/* to utf-8
+  if (match && TEXT_TYPE_REGEXP.test(match[1])) {
+    return 'UTF-8'
+  }
+
+  return false
+}
+
+/**
+ * Create a full Content-Type header given a MIME type or extension.
+ *
+ * @param {string} str
+ * @return {boolean|string}
+ */
+
+function contentType (str) {
+  // TODO: should this even be in this module?
+  if (!str || typeof str !== 'string') {
+    return false
+  }
+
+  var mime = str.indexOf('/') === -1
+    ? exports.lookup(str)
+    : str
+
+  if (!mime) {
+    return false
+  }
+
+  // TODO: use content-type or other module
+  if (mime.indexOf('charset') === -1) {
+    var charset = exports.charset(mime)
+    if (charset) mime += '; charset=' + charset.toLowerCase()
+  }
+
+  return mime
+}
+
+/**
+ * Get the default extension for a MIME type.
+ *
+ * @param {string} type
+ * @return {boolean|string}
+ */
+
+function extension (type) {
+  if (!type || typeof type !== 'string') {
+    return false
+  }
+
+  // TODO: use media-typer
+  var match = EXTRACT_TYPE_REGEXP.exec(type)
+
+  // get extensions
+  var exts = match && exports.extensions[match[1].toLowerCase()]
+
+  if (!exts || !exts.length) {
+    return false
+  }
+
+  return exts[0]
+}
+
+/**
+ * Lookup the MIME type for a file path/extension.
+ *
+ * @param {string} path
+ * @return {boolean|string}
+ */
+
+function lookup (path) {
+  if (!path || typeof path !== 'string') {
+    return false
+  }
+
+  // get the extension ("ext" or ".ext" or full path)
+  var extension = extname('x.' + path)
+    .toLowerCase()
+    .substr(1)
+
+  if (!extension) {
+    return false
+  }
+
+  return exports.types[extension] || false
+}
+
+/**
+ * Populate the extensions and types maps.
+ * @private
+ */
+
+function populateMaps (extensions, types) {
+  // source preference (least -> most)
+  var preference = ['nginx', 'apache', undefined, 'iana']
+
+  Object.keys(db).forEach(function forEachMimeType (type) {
+    var mime = db[type]
+    var exts = mime.extensions
+
+    if (!exts || !exts.length) {
+      return
+    }
+
+    // mime -> extensions
+    extensions[type] = exts
+
+    // extension -> mime
+    for (var i = 0; i < exts.length; i++) {
+      var extension = exts[i]
+
+      if (types[extension]) {
+        var from = preference.indexOf(db[types[extension]].source)
+        var to = preference.indexOf(mime.source)
+
+        if (types[extension] !== 'application/octet-stream' &&
+          (from > to || (from === to && types[extension].substr(0, 12) === 'application/'))) {
+          // skip the remapping
+          continue
+        }
+      }
+
+      // set the extension -> mime
+      types[extension] = type
+    }
+  })
+}
diff --git a/server/node_modules/mime-types/package.json b/server/node_modules/mime-types/package.json
new file mode 100644
index 0000000..bbef696
--- /dev/null
+++ b/server/node_modules/mime-types/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "mime-types",
+  "description": "The ultimate javascript content-type utility.",
+  "version": "2.1.35",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jeremiah Senkpiel <fishrock123@rocketmail.com> (https://searchbeam.jit.su)",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "mime",
+    "types"
+  ],
+  "repository": "jshttp/mime-types",
+  "dependencies": {
+    "mime-db": "1.52.0"
+  },
+  "devDependencies": {
+    "eslint": "7.32.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.25.4",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "5.2.0",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "9.2.2",
+    "nyc": "15.1.0"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec test/test.js",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/mime/.npmignore b/server/node_modules/mime/.npmignore
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/mime/CHANGELOG.md b/server/node_modules/mime/CHANGELOG.md
new file mode 100644
index 0000000..f127535
--- /dev/null
+++ b/server/node_modules/mime/CHANGELOG.md
@@ -0,0 +1,164 @@
+# Changelog
+
+## v1.6.0 (24/11/2017)
+*No changelog for this release.*
+
+---
+
+## v2.0.4 (24/11/2017)
+- [**closed**] Switch to mime-score module for resolving extension contention issues. [#182](https://github.com/broofa/node-mime/issues/182)
+- [**closed**] Update mime-db to 1.31.0 in v1.x branch [#181](https://github.com/broofa/node-mime/issues/181)
+
+---
+
+## v1.5.0 (22/11/2017)
+- [**closed**] need ES5 version ready in npm package [#179](https://github.com/broofa/node-mime/issues/179)
+- [**closed**] mime-db no trace of iWork - pages / numbers / etc. [#178](https://github.com/broofa/node-mime/issues/178)
+- [**closed**] How it works in brownser ? [#176](https://github.com/broofa/node-mime/issues/176)
+- [**closed**] Missing `./Mime` [#175](https://github.com/broofa/node-mime/issues/175)
+- [**closed**] Vulnerable Regular Expression [#167](https://github.com/broofa/node-mime/issues/167)
+
+---
+
+## v2.0.3 (25/09/2017)
+*No changelog for this release.*
+
+---
+
+## v1.4.1 (25/09/2017)
+- [**closed**] Issue when bundling with webpack [#172](https://github.com/broofa/node-mime/issues/172)
+
+---
+
+## v2.0.2 (15/09/2017)
+- [**V2**] fs.readFileSync is not a function [#165](https://github.com/broofa/node-mime/issues/165)
+- [**closed**] The extension for video/quicktime should map to .mov, not .qt [#164](https://github.com/broofa/node-mime/issues/164)
+- [**V2**] [v2 Feedback request] Mime class API [#163](https://github.com/broofa/node-mime/issues/163)
+- [**V2**] [v2 Feedback request] Resolving conflicts over extensions [#162](https://github.com/broofa/node-mime/issues/162)
+- [**V2**] Allow callers to load module with official, full, or no defined types.  [#161](https://github.com/broofa/node-mime/issues/161)
+- [**V2**] Use "facets" to resolve extension conflicts [#160](https://github.com/broofa/node-mime/issues/160)
+- [**V2**] Remove fs and path dependencies [#152](https://github.com/broofa/node-mime/issues/152)
+- [**V2**] Default content-type should not be application/octet-stream [#139](https://github.com/broofa/node-mime/issues/139)
+- [**V2**] reset mime-types [#124](https://github.com/broofa/node-mime/issues/124)
+- [**V2**] Extensionless paths should return null or false [#113](https://github.com/broofa/node-mime/issues/113)
+
+---
+
+## v2.0.1 (14/09/2017)
+- [**closed**] Changelog for v2.0 does not mention breaking changes [#171](https://github.com/broofa/node-mime/issues/171)
+- [**closed**] MIME breaking with 'class' declaration as it is without 'use strict mode' [#170](https://github.com/broofa/node-mime/issues/170)
+
+---
+
+## v2.0.0 (12/09/2017)
+- [**closed**] woff and woff2 [#168](https://github.com/broofa/node-mime/issues/168)
+
+---
+
+## v1.4.0 (28/08/2017)
+- [**closed**] support for ac3 voc files [#159](https://github.com/broofa/node-mime/issues/159)
+- [**closed**] Help understanding change from application/xml to text/xml [#158](https://github.com/broofa/node-mime/issues/158)
+- [**closed**] no longer able to override mimetype [#157](https://github.com/broofa/node-mime/issues/157)
+- [**closed**] application/vnd.adobe.photoshop [#147](https://github.com/broofa/node-mime/issues/147)
+- [**closed**] Directories should appear as something other than application/octet-stream [#135](https://github.com/broofa/node-mime/issues/135)
+- [**closed**] requested features [#131](https://github.com/broofa/node-mime/issues/131)
+- [**closed**] Make types.json loading optional? [#129](https://github.com/broofa/node-mime/issues/129)
+- [**closed**] Cannot find module './types.json' [#120](https://github.com/broofa/node-mime/issues/120)
+- [**V2**] .wav files show up as "audio/x-wav" instead of "audio/x-wave" [#118](https://github.com/broofa/node-mime/issues/118)
+- [**closed**] Don't be a pain in the ass for node community [#108](https://github.com/broofa/node-mime/issues/108)
+- [**closed**] don't make default_type global [#78](https://github.com/broofa/node-mime/issues/78)
+- [**closed**] mime.extension() fails if the content-type is parameterized [#74](https://github.com/broofa/node-mime/issues/74)
+
+---
+
+## v1.3.6 (11/05/2017)
+- [**closed**] .md should be text/markdown as of March 2016 [#154](https://github.com/broofa/node-mime/issues/154)
+- [**closed**] Error while installing mime [#153](https://github.com/broofa/node-mime/issues/153)
+- [**closed**] application/manifest+json [#149](https://github.com/broofa/node-mime/issues/149)
+- [**closed**] Dynamic adaptive streaming over HTTP (DASH) file extension typo [#141](https://github.com/broofa/node-mime/issues/141)
+- [**closed**] charsets image/png undefined [#140](https://github.com/broofa/node-mime/issues/140)
+- [**closed**] Mime-db dependency out of date [#130](https://github.com/broofa/node-mime/issues/130)
+- [**closed**] how to support plist？ [#126](https://github.com/broofa/node-mime/issues/126)
+- [**closed**] how does .types file format look like? [#123](https://github.com/broofa/node-mime/issues/123)
+- [**closed**] Feature: support for expanding MIME patterns [#121](https://github.com/broofa/node-mime/issues/121)
+- [**closed**] DEBUG_MIME doesn't work [#117](https://github.com/broofa/node-mime/issues/117)
+
+---
+
+## v1.3.4 (06/02/2015)
+*No changelog for this release.*
+
+---
+
+## v1.3.3 (06/02/2015)
+*No changelog for this release.*
+
+---
+
+## v1.3.1 (05/02/2015)
+- [**closed**] Consider adding support for Handlebars .hbs file ending [#111](https://github.com/broofa/node-mime/issues/111)
+- [**closed**] Consider adding support for hjson. [#110](https://github.com/broofa/node-mime/issues/110)
+- [**closed**] Add mime type for Opus audio files [#94](https://github.com/broofa/node-mime/issues/94)
+- [**closed**] Consider making the `Requesting New Types` information more visible [#77](https://github.com/broofa/node-mime/issues/77)
+
+---
+
+## v1.3.0 (05/02/2015)
+- [**closed**] Add common name? [#114](https://github.com/broofa/node-mime/issues/114)
+- [**closed**] application/x-yaml [#104](https://github.com/broofa/node-mime/issues/104)
+- [**closed**] Add mime type for WOFF file format 2.0 [#102](https://github.com/broofa/node-mime/issues/102)
+- [**closed**] application/x-msi for .msi [#99](https://github.com/broofa/node-mime/issues/99)
+- [**closed**] Add mimetype for gettext translation files [#98](https://github.com/broofa/node-mime/issues/98)
+- [**closed**] collaborators [#88](https://github.com/broofa/node-mime/issues/88)
+- [**closed**] getting errot in installation of mime module...any1 can help? [#87](https://github.com/broofa/node-mime/issues/87)
+- [**closed**] should application/json's charset be utf8? [#86](https://github.com/broofa/node-mime/issues/86)
+- [**closed**] Add "license" and "licenses" to package.json [#81](https://github.com/broofa/node-mime/issues/81)
+- [**closed**] lookup with extension-less file on Windows returns wrong type [#68](https://github.com/broofa/node-mime/issues/68)
+
+---
+
+## v1.2.11 (15/08/2013)
+- [**closed**] Update mime.types [#65](https://github.com/broofa/node-mime/issues/65)
+- [**closed**] Publish a new version [#63](https://github.com/broofa/node-mime/issues/63)
+- [**closed**] README should state upfront that "application/octet-stream" is default for unknown extension [#55](https://github.com/broofa/node-mime/issues/55)
+- [**closed**] Suggested improvement to the charset API [#52](https://github.com/broofa/node-mime/issues/52)
+
+---
+
+## v1.2.10 (25/07/2013)
+- [**closed**] Mime type for woff files should be application/font-woff and not application/x-font-woff [#62](https://github.com/broofa/node-mime/issues/62)
+- [**closed**] node.types in conflict with mime.types [#51](https://github.com/broofa/node-mime/issues/51)
+
+---
+
+## v1.2.9 (17/01/2013)
+- [**closed**] Please update "mime" NPM [#49](https://github.com/broofa/node-mime/issues/49)
+- [**closed**] Please add semicolon [#46](https://github.com/broofa/node-mime/issues/46)
+- [**closed**] parse full mime types [#43](https://github.com/broofa/node-mime/issues/43)
+
+---
+
+## v1.2.8 (10/01/2013)
+- [**closed**] /js directory mime is application/javascript. Is it correct? [#47](https://github.com/broofa/node-mime/issues/47)
+- [**closed**] Add mime types for lua code. [#45](https://github.com/broofa/node-mime/issues/45)
+
+---
+
+## v1.2.7 (19/10/2012)
+- [**closed**] cannot install 1.2.7 via npm [#41](https://github.com/broofa/node-mime/issues/41)
+- [**closed**] Transfer ownership to @broofa [#36](https://github.com/broofa/node-mime/issues/36)
+- [**closed**] it's wrong to set charset to UTF-8 for text [#30](https://github.com/broofa/node-mime/issues/30)
+- [**closed**] Allow multiple instances of MIME types container [#27](https://github.com/broofa/node-mime/issues/27)
+
+---
+
+## v1.2.5 (16/02/2012)
+- [**closed**] When looking up a types, check hasOwnProperty [#23](https://github.com/broofa/node-mime/issues/23)
+- [**closed**] Bump version to 1.2.2 [#18](https://github.com/broofa/node-mime/issues/18)
+- [**closed**] No license [#16](https://github.com/broofa/node-mime/issues/16)
+- [**closed**] Some types missing that are used by html5/css3 [#13](https://github.com/broofa/node-mime/issues/13)
+- [**closed**] npm install fails for 1.2.1 [#12](https://github.com/broofa/node-mime/issues/12)
+- [**closed**] image/pjpeg + image/x-png [#10](https://github.com/broofa/node-mime/issues/10)
+- [**closed**] symlink [#8](https://github.com/broofa/node-mime/issues/8)
+- [**closed**] gzip [#2](https://github.com/broofa/node-mime/issues/2)
+- [**closed**] ALL CAPS filenames return incorrect mime type [#1](https://github.com/broofa/node-mime/issues/1)
diff --git a/server/node_modules/mime/LICENSE b/server/node_modules/mime/LICENSE
new file mode 100644
index 0000000..d3f46f7
--- /dev/null
+++ b/server/node_modules/mime/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2010 Benjamin Thomas, Robert Kieffer
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/mime/README.md b/server/node_modules/mime/README.md
new file mode 100644
index 0000000..506fbe5
--- /dev/null
+++ b/server/node_modules/mime/README.md
@@ -0,0 +1,90 @@
+# mime
+
+Comprehensive MIME type mapping API based on mime-db module.
+
+## Install
+
+Install with [npm](http://github.com/isaacs/npm):
+
+    npm install mime
+
+## Contributing / Testing
+
+    npm run test
+
+## Command Line
+
+    mime [path_string]
+
+E.g.
+
+    > mime scripts/jquery.js
+    application/javascript
+
+## API - Queries
+
+### mime.lookup(path)
+Get the mime type associated with a file, if no mime type is found `application/octet-stream` is returned. Performs a case-insensitive lookup using the extension in `path` (the substring after the last '/' or '.').  E.g.
+
+```js
+var mime = require('mime');
+
+mime.lookup('/path/to/file.txt');         // => 'text/plain'
+mime.lookup('file.txt');                  // => 'text/plain'
+mime.lookup('.TXT');                      // => 'text/plain'
+mime.lookup('htm');                       // => 'text/html'
+```
+
+### mime.default_type
+Sets the mime type returned when `mime.lookup` fails to find the extension searched for. (Default is `application/octet-stream`.)
+
+### mime.extension(type)
+Get the default extension for `type`
+
+```js
+mime.extension('text/html');                 // => 'html'
+mime.extension('application/octet-stream');  // => 'bin'
+```
+
+### mime.charsets.lookup()
+
+Map mime-type to charset
+
+```js
+mime.charsets.lookup('text/plain');        // => 'UTF-8'
+```
+
+(The logic for charset lookups is pretty rudimentary.  Feel free to suggest improvements.)
+
+## API - Defining Custom Types
+
+Custom type mappings can be added on a per-project basis via the following APIs.
+
+### mime.define()
+
+Add custom mime/extension mappings
+
+```js
+mime.define({
+    'text/x-some-format': ['x-sf', 'x-sft', 'x-sfml'],
+    'application/x-my-type': ['x-mt', 'x-mtt'],
+    // etc ...
+});
+
+mime.lookup('x-sft');                 // => 'text/x-some-format'
+```
+
+The first entry in the extensions array is returned by `mime.extension()`. E.g.
+
+```js
+mime.extension('text/x-some-format'); // => 'x-sf'
+```
+
+### mime.load(filepath)
+
+Load mappings from an Apache ".types" format file
+
+```js
+mime.load('./my_project.types');
+```
+The .types file format is simple -  See the `types` dir for examples.
diff --git a/server/node_modules/mime/cli.js b/server/node_modules/mime/cli.js
new file mode 100755
index 0000000..20b1ffe
--- /dev/null
+++ b/server/node_modules/mime/cli.js
@@ -0,0 +1,8 @@
+#!/usr/bin/env node
+
+var mime = require('./mime.js');
+var file = process.argv[2];
+var type = mime.lookup(file);
+
+process.stdout.write(type + '\n');
+
diff --git a/server/node_modules/mime/mime.js b/server/node_modules/mime/mime.js
new file mode 100644
index 0000000..d7efbde
--- /dev/null
+++ b/server/node_modules/mime/mime.js
@@ -0,0 +1,108 @@
+var path = require('path');
+var fs = require('fs');
+
+function Mime() {
+  // Map of extension -> mime type
+  this.types = Object.create(null);
+
+  // Map of mime type -> extension
+  this.extensions = Object.create(null);
+}
+
+/**
+ * Define mimetype -> extension mappings.  Each key is a mime-type that maps
+ * to an array of extensions associated with the type.  The first extension is
+ * used as the default extension for the type.
+ *
+ * e.g. mime.define({'audio/ogg', ['oga', 'ogg', 'spx']});
+ *
+ * @param map (Object) type definitions
+ */
+Mime.prototype.define = function (map) {
+  for (var type in map) {
+    var exts = map[type];
+    for (var i = 0; i < exts.length; i++) {
+      if (process.env.DEBUG_MIME && this.types[exts[i]]) {
+        console.warn((this._loading || "define()").replace(/.*\//, ''), 'changes "' + exts[i] + '" extension type from ' +
+          this.types[exts[i]] + ' to ' + type);
+      }
+
+      this.types[exts[i]] = type;
+    }
+
+    // Default extension is the first one we encounter
+    if (!this.extensions[type]) {
+      this.extensions[type] = exts[0];
+    }
+  }
+};
+
+/**
+ * Load an Apache2-style ".types" file
+ *
+ * This may be called multiple times (it's expected).  Where files declare
+ * overlapping types/extensions, the last file wins.
+ *
+ * @param file (String) path of file to load.
+ */
+Mime.prototype.load = function(file) {
+  this._loading = file;
+  // Read file and split into lines
+  var map = {},
+      content = fs.readFileSync(file, 'ascii'),
+      lines = content.split(/[\r\n]+/);
+
+  lines.forEach(function(line) {
+    // Clean up whitespace/comments, and split into fields
+    var fields = line.replace(/\s*#.*|^\s*|\s*$/g, '').split(/\s+/);
+    map[fields.shift()] = fields;
+  });
+
+  this.define(map);
+
+  this._loading = null;
+};
+
+/**
+ * Lookup a mime type based on extension
+ */
+Mime.prototype.lookup = function(path, fallback) {
+  var ext = path.replace(/^.*[\.\/\\]/, '').toLowerCase();
+
+  return this.types[ext] || fallback || this.default_type;
+};
+
+/**
+ * Return file extension associated with a mime type
+ */
+Mime.prototype.extension = function(mimeType) {
+  var type = mimeType.match(/^\s*([^;\s]*)(?:;|\s|$)/)[1].toLowerCase();
+  return this.extensions[type];
+};
+
+// Default instance
+var mime = new Mime();
+
+// Define built-in types
+mime.define(require('./types.json'));
+
+// Default type
+mime.default_type = mime.lookup('bin');
+
+//
+// Additional API specific to the default instance
+//
+
+mime.Mime = Mime;
+
+/**
+ * Lookup a charset based on mime type.
+ */
+mime.charsets = {
+  lookup: function(mimeType, fallback) {
+    // Assume text types are utf8
+    return (/^text\/|^application\/(javascript|json)/).test(mimeType) ? 'UTF-8' : fallback;
+  }
+};
+
+module.exports = mime;
diff --git a/server/node_modules/mime/package.json b/server/node_modules/mime/package.json
new file mode 100644
index 0000000..6bd24bc
--- /dev/null
+++ b/server/node_modules/mime/package.json
@@ -0,0 +1,44 @@
+{
+  "author": {
+    "name": "Robert Kieffer",
+    "url": "http://github.com/broofa",
+    "email": "robert@broofa.com"
+  },
+  "bin": {
+    "mime": "cli.js"
+  },
+  "engines": {
+    "node": ">=4"
+  },
+  "contributors": [
+    {
+      "name": "Benjamin Thomas",
+      "url": "http://github.com/bentomas",
+      "email": "benjamin@benjaminthomas.org"
+    }
+  ],
+  "description": "A comprehensive library for mime-type mapping",
+  "license": "MIT",
+  "dependencies": {},
+  "devDependencies": {
+    "github-release-notes": "0.13.1",
+    "mime-db": "1.31.0",
+    "mime-score": "1.1.0"
+  },
+  "scripts": {
+    "prepare": "node src/build.js",
+    "changelog": "gren changelog --tags=all --generate --override",
+    "test": "node src/test.js"
+  },
+  "keywords": [
+    "util",
+    "mime"
+  ],
+  "main": "mime.js",
+  "name": "mime",
+  "repository": {
+    "url": "https://github.com/broofa/node-mime",
+    "type": "git"
+  },
+  "version": "1.6.0"
+}
diff --git a/server/node_modules/mime/src/build.js b/server/node_modules/mime/src/build.js
new file mode 100755
index 0000000..4928e48
--- /dev/null
+++ b/server/node_modules/mime/src/build.js
@@ -0,0 +1,53 @@
+#!/usr/bin/env node
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const mimeScore = require('mime-score');
+
+let db = require('mime-db');
+let chalk = require('chalk');
+
+const STANDARD_FACET_SCORE = 900;
+
+const byExtension = {};
+
+// Clear out any conflict extensions in mime-db
+for (let type in db) {
+  let entry = db[type];
+  entry.type = type;
+
+  if (!entry.extensions) continue;
+
+  entry.extensions.forEach(ext => {
+    if (ext in byExtension) {
+      const e0 = entry;
+      const e1 = byExtension[ext];
+      e0.pri = mimeScore(e0.type, e0.source);
+      e1.pri = mimeScore(e1.type, e1.source);
+
+      let drop = e0.pri < e1.pri ? e0 : e1;
+      let keep = e0.pri >= e1.pri ? e0 : e1;
+      drop.extensions = drop.extensions.filter(e => e !== ext);
+
+      console.log(`${ext}: Keeping ${chalk.green(keep.type)} (${keep.pri}), dropping ${chalk.red(drop.type)} (${drop.pri})`);
+    }
+    byExtension[ext] = entry;
+  });
+}
+
+function writeTypesFile(types, path) {
+  fs.writeFileSync(path, JSON.stringify(types));
+}
+
+// Segregate into standard and non-standard types based on facet per
+// https://tools.ietf.org/html/rfc6838#section-3.1
+const types = {};
+
+Object.keys(db).sort().forEach(k => {
+  const entry = db[k];
+  types[entry.type] = entry.extensions;
+});
+
+writeTypesFile(types, path.join(__dirname, '..', 'types.json'));
diff --git a/server/node_modules/mime/src/test.js b/server/node_modules/mime/src/test.js
new file mode 100644
index 0000000..42958a2
--- /dev/null
+++ b/server/node_modules/mime/src/test.js
@@ -0,0 +1,60 @@
+/**
+ * Usage: node test.js
+ */
+
+var mime = require('../mime');
+var assert = require('assert');
+var path = require('path');
+
+//
+// Test mime lookups
+//
+
+assert.equal('text/plain', mime.lookup('text.txt'));     // normal file
+assert.equal('text/plain', mime.lookup('TEXT.TXT'));     // uppercase
+assert.equal('text/plain', mime.lookup('dir/text.txt')); // dir + file
+assert.equal('text/plain', mime.lookup('.text.txt'));    // hidden file
+assert.equal('text/plain', mime.lookup('.txt'));         // nameless
+assert.equal('text/plain', mime.lookup('txt'));          // extension-only
+assert.equal('text/plain', mime.lookup('/txt'));         // extension-less ()
+assert.equal('text/plain', mime.lookup('\\txt'));        // Windows, extension-less
+assert.equal('application/octet-stream', mime.lookup('text.nope')); // unrecognized
+assert.equal('fallback', mime.lookup('text.fallback', 'fallback')); // alternate default
+
+//
+// Test extensions
+//
+
+assert.equal('txt', mime.extension(mime.types.text));
+assert.equal('html', mime.extension(mime.types.htm));
+assert.equal('bin', mime.extension('application/octet-stream'));
+assert.equal('bin', mime.extension('application/octet-stream '));
+assert.equal('html', mime.extension(' text/html; charset=UTF-8'));
+assert.equal('html', mime.extension('text/html; charset=UTF-8 '));
+assert.equal('html', mime.extension('text/html; charset=UTF-8'));
+assert.equal('html', mime.extension('text/html ; charset=UTF-8'));
+assert.equal('html', mime.extension('text/html;charset=UTF-8'));
+assert.equal('html', mime.extension('text/Html;charset=UTF-8'));
+assert.equal(undefined, mime.extension('unrecognized'));
+
+//
+// Test node.types lookups
+//
+
+assert.equal('font/woff', mime.lookup('file.woff'));
+assert.equal('application/octet-stream', mime.lookup('file.buffer'));
+// TODO: Uncomment once #157 is resolved
+// assert.equal('audio/mp4', mime.lookup('file.m4a'));
+assert.equal('font/otf', mime.lookup('file.otf'));
+
+//
+// Test charsets
+//
+
+assert.equal('UTF-8', mime.charsets.lookup('text/plain'));
+assert.equal('UTF-8', mime.charsets.lookup(mime.types.js));
+assert.equal('UTF-8', mime.charsets.lookup(mime.types.json));
+assert.equal(undefined, mime.charsets.lookup(mime.types.bin));
+assert.equal('fallback', mime.charsets.lookup('application/octet-stream', 'fallback'));
+
+console.log('\nAll tests passed');
diff --git a/server/node_modules/mime/types.json b/server/node_modules/mime/types.json
new file mode 100644
index 0000000..bec78ab
--- /dev/null
+++ b/server/node_modules/mime/types.json
@@ -0,0 +1 @@
+{"application/andrew-inset":["ez"],"application/applixware":["aw"],"application/atom+xml":["atom"],"application/atomcat+xml":["atomcat"],"application/atomsvc+xml":["atomsvc"],"application/bdoc":["bdoc"],"application/ccxml+xml":["ccxml"],"application/cdmi-capability":["cdmia"],"application/cdmi-container":["cdmic"],"application/cdmi-domain":["cdmid"],"application/cdmi-object":["cdmio"],"application/cdmi-queue":["cdmiq"],"application/cu-seeme":["cu"],"application/dash+xml":["mpd"],"application/davmount+xml":["davmount"],"application/docbook+xml":["dbk"],"application/dssc+der":["dssc"],"application/dssc+xml":["xdssc"],"application/ecmascript":["ecma"],"application/emma+xml":["emma"],"application/epub+zip":["epub"],"application/exi":["exi"],"application/font-tdpfr":["pfr"],"application/font-woff":[],"application/font-woff2":[],"application/geo+json":["geojson"],"application/gml+xml":["gml"],"application/gpx+xml":["gpx"],"application/gxf":["gxf"],"application/gzip":["gz"],"application/hyperstudio":["stk"],"application/inkml+xml":["ink","inkml"],"application/ipfix":["ipfix"],"application/java-archive":["jar","war","ear"],"application/java-serialized-object":["ser"],"application/java-vm":["class"],"application/javascript":["js","mjs"],"application/json":["json","map"],"application/json5":["json5"],"application/jsonml+json":["jsonml"],"application/ld+json":["jsonld"],"application/lost+xml":["lostxml"],"application/mac-binhex40":["hqx"],"application/mac-compactpro":["cpt"],"application/mads+xml":["mads"],"application/manifest+json":["webmanifest"],"application/marc":["mrc"],"application/marcxml+xml":["mrcx"],"application/mathematica":["ma","nb","mb"],"application/mathml+xml":["mathml"],"application/mbox":["mbox"],"application/mediaservercontrol+xml":["mscml"],"application/metalink+xml":["metalink"],"application/metalink4+xml":["meta4"],"application/mets+xml":["mets"],"application/mods+xml":["mods"],"application/mp21":["m21","mp21"],"application/mp4":["mp4s","m4p"],"application/msword":["doc","dot"],"application/mxf":["mxf"],"application/octet-stream":["bin","dms","lrf","mar","so","dist","distz","pkg","bpk","dump","elc","deploy","exe","dll","deb","dmg","iso","img","msi","msp","msm","buffer"],"application/oda":["oda"],"application/oebps-package+xml":["opf"],"application/ogg":["ogx"],"application/omdoc+xml":["omdoc"],"application/onenote":["onetoc","onetoc2","onetmp","onepkg"],"application/oxps":["oxps"],"application/patch-ops-error+xml":["xer"],"application/pdf":["pdf"],"application/pgp-encrypted":["pgp"],"application/pgp-signature":["asc","sig"],"application/pics-rules":["prf"],"application/pkcs10":["p10"],"application/pkcs7-mime":["p7m","p7c"],"application/pkcs7-signature":["p7s"],"application/pkcs8":["p8"],"application/pkix-attr-cert":["ac"],"application/pkix-cert":["cer"],"application/pkix-crl":["crl"],"application/pkix-pkipath":["pkipath"],"application/pkixcmp":["pki"],"application/pls+xml":["pls"],"application/postscript":["ai","eps","ps"],"application/prs.cww":["cww"],"application/pskc+xml":["pskcxml"],"application/raml+yaml":["raml"],"application/rdf+xml":["rdf"],"application/reginfo+xml":["rif"],"application/relax-ng-compact-syntax":["rnc"],"application/resource-lists+xml":["rl"],"application/resource-lists-diff+xml":["rld"],"application/rls-services+xml":["rs"],"application/rpki-ghostbusters":["gbr"],"application/rpki-manifest":["mft"],"application/rpki-roa":["roa"],"application/rsd+xml":["rsd"],"application/rss+xml":["rss"],"application/rtf":["rtf"],"application/sbml+xml":["sbml"],"application/scvp-cv-request":["scq"],"application/scvp-cv-response":["scs"],"application/scvp-vp-request":["spq"],"application/scvp-vp-response":["spp"],"application/sdp":["sdp"],"application/set-payment-initiation":["setpay"],"application/set-registration-initiation":["setreg"],"application/shf+xml":["shf"],"application/smil+xml":["smi","smil"],"application/sparql-query":["rq"],"application/sparql-results+xml":["srx"],"application/srgs":["gram"],"application/srgs+xml":["grxml"],"application/sru+xml":["sru"],"application/ssdl+xml":["ssdl"],"application/ssml+xml":["ssml"],"application/tei+xml":["tei","teicorpus"],"application/thraud+xml":["tfi"],"application/timestamped-data":["tsd"],"application/vnd.3gpp.pic-bw-large":["plb"],"application/vnd.3gpp.pic-bw-small":["psb"],"application/vnd.3gpp.pic-bw-var":["pvb"],"application/vnd.3gpp2.tcap":["tcap"],"application/vnd.3m.post-it-notes":["pwn"],"application/vnd.accpac.simply.aso":["aso"],"application/vnd.accpac.simply.imp":["imp"],"application/vnd.acucobol":["acu"],"application/vnd.acucorp":["atc","acutc"],"application/vnd.adobe.air-application-installer-package+zip":["air"],"application/vnd.adobe.formscentral.fcdt":["fcdt"],"application/vnd.adobe.fxp":["fxp","fxpl"],"application/vnd.adobe.xdp+xml":["xdp"],"application/vnd.adobe.xfdf":["xfdf"],"application/vnd.ahead.space":["ahead"],"application/vnd.airzip.filesecure.azf":["azf"],"application/vnd.airzip.filesecure.azs":["azs"],"appli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diff --git a/server/node_modules/mimic-response/index.d.ts b/server/node_modules/mimic-response/index.d.ts
new file mode 100644
index 0000000..65a51e9
--- /dev/null
+++ b/server/node_modules/mimic-response/index.d.ts
@@ -0,0 +1,17 @@
+import {IncomingMessage} from 'http';
+
+/**
+Mimic a [Node.js HTTP response stream](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
+
+Makes `toStream` include the properties from `fromStream`.
+
+@param fromStream - The stream to copy the properties from.
+@param toStream - The stream to copy the properties to.
+@return The same object as `toStream`.
+*/
+declare function mimicResponse<T extends NodeJS.ReadableStream>(
+	fromStream: IncomingMessage, // eslint-disable-line @typescript-eslint/prefer-readonly-parameter-types
+	toStream: T,
+): T & IncomingMessage;
+
+export = mimicResponse;
diff --git a/server/node_modules/mimic-response/index.js b/server/node_modules/mimic-response/index.js
new file mode 100644
index 0000000..404e111
--- /dev/null
+++ b/server/node_modules/mimic-response/index.js
@@ -0,0 +1,77 @@
+'use strict';
+
+// We define these manually to ensure they're always copied
+// even if they would move up the prototype chain
+// https://nodejs.org/api/http.html#http_class_http_incomingmessage
+const knownProperties = [
+	'aborted',
+	'complete',
+	'headers',
+	'httpVersion',
+	'httpVersionMinor',
+	'httpVersionMajor',
+	'method',
+	'rawHeaders',
+	'rawTrailers',
+	'setTimeout',
+	'socket',
+	'statusCode',
+	'statusMessage',
+	'trailers',
+	'url'
+];
+
+module.exports = (fromStream, toStream) => {
+	if (toStream._readableState.autoDestroy) {
+		throw new Error('The second stream must have the `autoDestroy` option set to `false`');
+	}
+
+	const fromProperties = new Set(Object.keys(fromStream).concat(knownProperties));
+
+	const properties = {};
+
+	for (const property of fromProperties) {
+		// Don't overwrite existing properties.
+		if (property in toStream) {
+			continue;
+		}
+
+		properties[property] = {
+			get() {
+				const value = fromStream[property];
+				const isFunction = typeof value === 'function';
+
+				return isFunction ? value.bind(fromStream) : value;
+			},
+			set(value) {
+				fromStream[property] = value;
+			},
+			enumerable: true,
+			configurable: false
+		};
+	}
+
+	Object.defineProperties(toStream, properties);
+
+	fromStream.once('aborted', () => {
+		toStream.destroy();
+
+		toStream.emit('aborted');
+	});
+
+	fromStream.once('close', () => {
+		if (fromStream.complete) {
+			if (toStream.readable) {
+				toStream.once('end', () => {
+					toStream.emit('close');
+				});
+			} else {
+				toStream.emit('close');
+			}
+		} else {
+			toStream.emit('close');
+		}
+	});
+
+	return toStream;
+};
diff --git a/server/node_modules/mimic-response/license b/server/node_modules/mimic-response/license
new file mode 100644
index 0000000..fa7ceba
--- /dev/null
+++ b/server/node_modules/mimic-response/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/mimic-response/package.json b/server/node_modules/mimic-response/package.json
new file mode 100644
index 0000000..d478b0f
--- /dev/null
+++ b/server/node_modules/mimic-response/package.json
@@ -0,0 +1,42 @@
+{
+	"name": "mimic-response",
+	"version": "3.1.0",
+	"description": "Mimic a Node.js HTTP response stream",
+	"license": "MIT",
+	"repository": "sindresorhus/mimic-response",
+	"funding": "https://github.com/sponsors/sindresorhus",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "https://sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=10"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd"
+	},
+	"files": [
+		"index.d.ts",
+		"index.js"
+	],
+	"keywords": [
+		"mimic",
+		"response",
+		"stream",
+		"http",
+		"https",
+		"request",
+		"get",
+		"core"
+	],
+	"devDependencies": {
+		"@types/node": "^14.0.1",
+		"ava": "^2.4.0",
+		"create-test-server": "^2.4.0",
+		"p-event": "^4.1.0",
+		"pify": "^5.0.0",
+		"tsd": "^0.11.0",
+		"xo": "^0.30.0"
+	}
+}
diff --git a/server/node_modules/mimic-response/readme.md b/server/node_modules/mimic-response/readme.md
new file mode 100644
index 0000000..e968620
--- /dev/null
+++ b/server/node_modules/mimic-response/readme.md
@@ -0,0 +1,78 @@
+# mimic-response [![Build Status](https://travis-ci.com/sindresorhus/mimic-response.svg?branch=master)](https://travis-ci.com/sindresorhus/mimic-response)
+
+> Mimic a [Node.js HTTP response stream](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
+
+## Install
+
+```
+$ npm install mimic-response
+```
+
+## Usage
+
+```js
+const stream = require('stream');
+const mimicResponse = require('mimic-response');
+
+const responseStream = getHttpResponseStream();
+const myStream = new stream.PassThrough();
+
+mimicResponse(responseStream, myStream);
+
+console.log(myStream.statusCode);
+//=> 200
+```
+
+## API
+
+### mimicResponse(from, to)
+
+**Note #1:** The `from.destroy(error)` function is not proxied. You have to call it manually:
+
+```js
+const stream = require('stream');
+const mimicResponse = require('mimic-response');
+
+const responseStream = getHttpResponseStream();
+
+const myStream = new stream.PassThrough({
+	destroy(error, callback) {
+		responseStream.destroy();
+
+		callback(error);
+	}
+});
+
+myStream.destroy();
+```
+
+Please note that `myStream` and `responseStream` never throws. The error is passed to the request instead.
+
+#### from
+
+Type: `Stream`
+
+[Node.js HTTP response stream.](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
+
+#### to
+
+Type: `Stream`
+
+Any stream.
+
+## Related
+
+- [mimic-fn](https://github.com/sindresorhus/mimic-fn) - Make a function mimic another one
+- [clone-response](https://github.com/lukechilds/clone-response) - Clone a Node.js response stream
+
+---
+
+<div align="center">
+	<b>
+		<a href="https://tidelift.com/subscription/pkg/npm-mimic-response?utm_source=npm-mimic-response&utm_medium=referral&utm_campaign=readme">Get professional support for this package with a Tidelift subscription</a>
+	</b>
+	<br>
+	<sub>
+		Tidelift helps make open source sustainable for maintainers while giving companies<br>assurances about security, maintenance, and licensing for their dependencies.
+	</sub>
+</div>
diff --git a/server/node_modules/minimatch/LICENSE b/server/node_modules/minimatch/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/minimatch/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/minimatch/README.md b/server/node_modules/minimatch/README.md
new file mode 100644
index 0000000..33ede1d
--- /dev/null
+++ b/server/node_modules/minimatch/README.md
@@ -0,0 +1,230 @@
+# minimatch
+
+A minimal matching utility.
+
+[![Build Status](https://travis-ci.org/isaacs/minimatch.svg?branch=master)](http://travis-ci.org/isaacs/minimatch)
+
+
+This is the matching library used internally by npm.
+
+It works by converting glob expressions into JavaScript `RegExp`
+objects.
+
+## Usage
+
+```javascript
+var minimatch = require("minimatch")
+
+minimatch("bar.foo", "*.foo") // true!
+minimatch("bar.foo", "*.bar") // false!
+minimatch("bar.foo", "*.+(bar|foo)", { debug: true }) // true, and noisy!
+```
+
+## Features
+
+Supports these glob features:
+
+* Brace Expansion
+* Extended glob matching
+* "Globstar" `**` matching
+
+See:
+
+* `man sh`
+* `man bash`
+* `man 3 fnmatch`
+* `man 5 gitignore`
+
+## Minimatch Class
+
+Create a minimatch object by instantiating the `minimatch.Minimatch` class.
+
+```javascript
+var Minimatch = require("minimatch").Minimatch
+var mm = new Minimatch(pattern, options)
+```
+
+### Properties
+
+* `pattern` The original pattern the minimatch object represents.
+* `options` The options supplied to the constructor.
+* `set` A 2-dimensional array of regexp or string expressions.
+  Each row in the
+  array corresponds to a brace-expanded pattern.  Each item in the row
+  corresponds to a single path-part.  For example, the pattern
+  `{a,b/c}/d` would expand to a set of patterns like:
+
+        [ [ a, d ]
+        , [ b, c, d ] ]
+
+    If a portion of the pattern doesn't have any "magic" in it
+    (that is, it's something like `"foo"` rather than `fo*o?`), then it
+    will be left as a string rather than converted to a regular
+    expression.
+
+* `regexp` Created by the `makeRe` method.  A single regular expression
+  expressing the entire pattern.  This is useful in cases where you wish
+  to use the pattern somewhat like `fnmatch(3)` with `FNM_PATH` enabled.
+* `negate` True if the pattern is negated.
+* `comment` True if the pattern is a comment.
+* `empty` True if the pattern is `""`.
+
+### Methods
+
+* `makeRe` Generate the `regexp` member if necessary, and return it.
+  Will return `false` if the pattern is invalid.
+* `match(fname)` Return true if the filename matches the pattern, or
+  false otherwise.
+* `matchOne(fileArray, patternArray, partial)` Take a `/`-split
+  filename, and match it against a single row in the `regExpSet`.  This
+  method is mainly for internal use, but is exposed so that it can be
+  used by a glob-walker that needs to avoid excessive filesystem calls.
+
+All other methods are internal, and will be called as necessary.
+
+### minimatch(path, pattern, options)
+
+Main export.  Tests a path against the pattern using the options.
+
+```javascript
+var isJS = minimatch(file, "*.js", { matchBase: true })
+```
+
+### minimatch.filter(pattern, options)
+
+Returns a function that tests its
+supplied argument, suitable for use with `Array.filter`.  Example:
+
+```javascript
+var javascripts = fileList.filter(minimatch.filter("*.js", {matchBase: true}))
+```
+
+### minimatch.match(list, pattern, options)
+
+Match against the list of
+files, in the style of fnmatch or glob.  If nothing is matched, and
+options.nonull is set, then return a list containing the pattern itself.
+
+```javascript
+var javascripts = minimatch.match(fileList, "*.js", {matchBase: true}))
+```
+
+### minimatch.makeRe(pattern, options)
+
+Make a regular expression object from the pattern.
+
+## Options
+
+All options are `false` by default.
+
+### debug
+
+Dump a ton of stuff to stderr.
+
+### nobrace
+
+Do not expand `{a,b}` and `{1..3}` brace sets.
+
+### noglobstar
+
+Disable `**` matching against multiple folder names.
+
+### dot
+
+Allow patterns to match filenames starting with a period, even if
+the pattern does not explicitly have a period in that spot.
+
+Note that by default, `a/**/b` will **not** match `a/.d/b`, unless `dot`
+is set.
+
+### noext
+
+Disable "extglob" style patterns like `+(a|b)`.
+
+### nocase
+
+Perform a case-insensitive match.
+
+### nonull
+
+When a match is not found by `minimatch.match`, return a list containing
+the pattern itself if this option is set.  When not set, an empty list
+is returned if there are no matches.
+
+### matchBase
+
+If set, then patterns without slashes will be matched
+against the basename of the path if it contains slashes.  For example,
+`a?b` would match the path `/xyz/123/acb`, but not `/xyz/acb/123`.
+
+### nocomment
+
+Suppress the behavior of treating `#` at the start of a pattern as a
+comment.
+
+### nonegate
+
+Suppress the behavior of treating a leading `!` character as negation.
+
+### flipNegate
+
+Returns from negate expressions the same as if they were not negated.
+(Ie, true on a hit, false on a miss.)
+
+### partial
+
+Compare a partial path to a pattern.  As long as the parts of the path that
+are present are not contradicted by the pattern, it will be treated as a
+match.  This is useful in applications where you're walking through a
+folder structure, and don't yet have the full path, but want to ensure that
+you do not walk down paths that can never be a match.
+
+For example,
+
+```js
+minimatch('/a/b', '/a/*/c/d', { partial: true })  // true, might be /a/b/c/d
+minimatch('/a/b', '/**/d', { partial: true })     // true, might be /a/b/.../d
+minimatch('/x/y/z', '/a/**/z', { partial: true }) // false, because x !== a
+```
+
+### allowWindowsEscape
+
+Windows path separator `\` is by default converted to `/`, which
+prohibits the usage of `\` as a escape character. This flag skips that
+behavior and allows using the escape character.
+
+## Comparisons to other fnmatch/glob implementations
+
+While strict compliance with the existing standards is a worthwhile
+goal, some discrepancies exist between minimatch and other
+implementations, and are intentional.
+
+If the pattern starts with a `!` character, then it is negated.  Set the
+`nonegate` flag to suppress this behavior, and treat leading `!`
+characters normally.  This is perhaps relevant if you wish to start the
+pattern with a negative extglob pattern like `!(a|B)`.  Multiple `!`
+characters at the start of a pattern will negate the pattern multiple
+times.
+
+If a pattern starts with `#`, then it is treated as a comment, and
+will not match anything.  Use `\#` to match a literal `#` at the
+start of a line, or set the `nocomment` flag to suppress this behavior.
+
+The double-star character `**` is supported by default, unless the
+`noglobstar` flag is set.  This is supported in the manner of bsdglob
+and bash 4.1, where `**` only has special significance if it is the only
+thing in a path part.  That is, `a/**/b` will match `a/x/y/b`, but
+`a/**b` will not.
+
+If an escaped pattern has no matches, and the `nonull` flag is set,
+then minimatch.match returns the pattern as-provided, rather than
+interpreting the character escapes.  For example,
+`minimatch.match([], "\\*a\\?")` will return `"\\*a\\?"` rather than
+`"*a?"`.  This is akin to setting the `nullglob` option in bash, except
+that it does not resolve escaped pattern characters.
+
+If brace expansion is not disabled, then it is performed before any
+other interpretation of the glob pattern.  Thus, a pattern like
+`+(a|{b),c)}`, which would not be valid in bash or zsh, is expanded
+**first** into the set of `+(a|b)` and `+(a|c)`, and those patterns are
+checked for validity.  Since those two are valid, matching proceeds.
diff --git a/server/node_modules/minimatch/minimatch.js b/server/node_modules/minimatch/minimatch.js
new file mode 100644
index 0000000..fda45ad
--- /dev/null
+++ b/server/node_modules/minimatch/minimatch.js
@@ -0,0 +1,947 @@
+module.exports = minimatch
+minimatch.Minimatch = Minimatch
+
+var path = (function () { try { return require('path') } catch (e) {}}()) || {
+  sep: '/'
+}
+minimatch.sep = path.sep
+
+var GLOBSTAR = minimatch.GLOBSTAR = Minimatch.GLOBSTAR = {}
+var expand = require('brace-expansion')
+
+var plTypes = {
+  '!': { open: '(?:(?!(?:', close: '))[^/]*?)'},
+  '?': { open: '(?:', close: ')?' },
+  '+': { open: '(?:', close: ')+' },
+  '*': { open: '(?:', close: ')*' },
+  '@': { open: '(?:', close: ')' }
+}
+
+// any single thing other than /
+// don't need to escape / when using new RegExp()
+var qmark = '[^/]'
+
+// * => any number of characters
+var star = qmark + '*?'
+
+// ** when dots are allowed.  Anything goes, except .. and .
+// not (^ or / followed by one or two dots followed by $ or /),
+// followed by anything, any number of times.
+var twoStarDot = '(?:(?!(?:\\\/|^)(?:\\.{1,2})($|\\\/)).)*?'
+
+// not a ^ or / followed by a dot,
+// followed by anything, any number of times.
+var twoStarNoDot = '(?:(?!(?:\\\/|^)\\.).)*?'
+
+// characters that need to be escaped in RegExp.
+var reSpecials = charSet('().*{}+?[]^$\\!')
+
+// "abc" -> { a:true, b:true, c:true }
+function charSet (s) {
+  return s.split('').reduce(function (set, c) {
+    set[c] = true
+    return set
+  }, {})
+}
+
+// normalizes slashes.
+var slashSplit = /\/+/
+
+minimatch.filter = filter
+function filter (pattern, options) {
+  options = options || {}
+  return function (p, i, list) {
+    return minimatch(p, pattern, options)
+  }
+}
+
+function ext (a, b) {
+  b = b || {}
+  var t = {}
+  Object.keys(a).forEach(function (k) {
+    t[k] = a[k]
+  })
+  Object.keys(b).forEach(function (k) {
+    t[k] = b[k]
+  })
+  return t
+}
+
+minimatch.defaults = function (def) {
+  if (!def || typeof def !== 'object' || !Object.keys(def).length) {
+    return minimatch
+  }
+
+  var orig = minimatch
+
+  var m = function minimatch (p, pattern, options) {
+    return orig(p, pattern, ext(def, options))
+  }
+
+  m.Minimatch = function Minimatch (pattern, options) {
+    return new orig.Minimatch(pattern, ext(def, options))
+  }
+  m.Minimatch.defaults = function defaults (options) {
+    return orig.defaults(ext(def, options)).Minimatch
+  }
+
+  m.filter = function filter (pattern, options) {
+    return orig.filter(pattern, ext(def, options))
+  }
+
+  m.defaults = function defaults (options) {
+    return orig.defaults(ext(def, options))
+  }
+
+  m.makeRe = function makeRe (pattern, options) {
+    return orig.makeRe(pattern, ext(def, options))
+  }
+
+  m.braceExpand = function braceExpand (pattern, options) {
+    return orig.braceExpand(pattern, ext(def, options))
+  }
+
+  m.match = function (list, pattern, options) {
+    return orig.match(list, pattern, ext(def, options))
+  }
+
+  return m
+}
+
+Minimatch.defaults = function (def) {
+  return minimatch.defaults(def).Minimatch
+}
+
+function minimatch (p, pattern, options) {
+  assertValidPattern(pattern)
+
+  if (!options) options = {}
+
+  // shortcut: comments match nothing.
+  if (!options.nocomment && pattern.charAt(0) === '#') {
+    return false
+  }
+
+  return new Minimatch(pattern, options).match(p)
+}
+
+function Minimatch (pattern, options) {
+  if (!(this instanceof Minimatch)) {
+    return new Minimatch(pattern, options)
+  }
+
+  assertValidPattern(pattern)
+
+  if (!options) options = {}
+
+  pattern = pattern.trim()
+
+  // windows support: need to use /, not \
+  if (!options.allowWindowsEscape && path.sep !== '/') {
+    pattern = pattern.split(path.sep).join('/')
+  }
+
+  this.options = options
+  this.set = []
+  this.pattern = pattern
+  this.regexp = null
+  this.negate = false
+  this.comment = false
+  this.empty = false
+  this.partial = !!options.partial
+
+  // make the set of regexps etc.
+  this.make()
+}
+
+Minimatch.prototype.debug = function () {}
+
+Minimatch.prototype.make = make
+function make () {
+  var pattern = this.pattern
+  var options = this.options
+
+  // empty patterns and comments match nothing.
+  if (!options.nocomment && pattern.charAt(0) === '#') {
+    this.comment = true
+    return
+  }
+  if (!pattern) {
+    this.empty = true
+    return
+  }
+
+  // step 1: figure out negation, etc.
+  this.parseNegate()
+
+  // step 2: expand braces
+  var set = this.globSet = this.braceExpand()
+
+  if (options.debug) this.debug = function debug() { console.error.apply(console, arguments) }
+
+  this.debug(this.pattern, set)
+
+  // step 3: now we have a set, so turn each one into a series of path-portion
+  // matching patterns.
+  // These will be regexps, except in the case of "**", which is
+  // set to the GLOBSTAR object for globstar behavior,
+  // and will not contain any / characters
+  set = this.globParts = set.map(function (s) {
+    return s.split(slashSplit)
+  })
+
+  this.debug(this.pattern, set)
+
+  // glob --> regexps
+  set = set.map(function (s, si, set) {
+    return s.map(this.parse, this)
+  }, this)
+
+  this.debug(this.pattern, set)
+
+  // filter out everything that didn't compile properly.
+  set = set.filter(function (s) {
+    return s.indexOf(false) === -1
+  })
+
+  this.debug(this.pattern, set)
+
+  this.set = set
+}
+
+Minimatch.prototype.parseNegate = parseNegate
+function parseNegate () {
+  var pattern = this.pattern
+  var negate = false
+  var options = this.options
+  var negateOffset = 0
+
+  if (options.nonegate) return
+
+  for (var i = 0, l = pattern.length
+    ; i < l && pattern.charAt(i) === '!'
+    ; i++) {
+    negate = !negate
+    negateOffset++
+  }
+
+  if (negateOffset) this.pattern = pattern.substr(negateOffset)
+  this.negate = negate
+}
+
+// Brace expansion:
+// a{b,c}d -> abd acd
+// a{b,}c -> abc ac
+// a{0..3}d -> a0d a1d a2d a3d
+// a{b,c{d,e}f}g -> abg acdfg acefg
+// a{b,c}d{e,f}g -> abdeg acdeg abdeg abdfg
+//
+// Invalid sets are not expanded.
+// a{2..}b -> a{2..}b
+// a{b}c -> a{b}c
+minimatch.braceExpand = function (pattern, options) {
+  return braceExpand(pattern, options)
+}
+
+Minimatch.prototype.braceExpand = braceExpand
+
+function braceExpand (pattern, options) {
+  if (!options) {
+    if (this instanceof Minimatch) {
+      options = this.options
+    } else {
+      options = {}
+    }
+  }
+
+  pattern = typeof pattern === 'undefined'
+    ? this.pattern : pattern
+
+  assertValidPattern(pattern)
+
+  // Thanks to Yeting Li <https://github.com/yetingli> for
+  // improving this regexp to avoid a ReDOS vulnerability.
+  if (options.nobrace || !/\{(?:(?!\{).)*\}/.test(pattern)) {
+    // shortcut. no need to expand.
+    return [pattern]
+  }
+
+  return expand(pattern)
+}
+
+var MAX_PATTERN_LENGTH = 1024 * 64
+var assertValidPattern = function (pattern) {
+  if (typeof pattern !== 'string') {
+    throw new TypeError('invalid pattern')
+  }
+
+  if (pattern.length > MAX_PATTERN_LENGTH) {
+    throw new TypeError('pattern is too long')
+  }
+}
+
+// parse a component of the expanded set.
+// At this point, no pattern may contain "/" in it
+// so we're going to return a 2d array, where each entry is the full
+// pattern, split on '/', and then turned into a regular expression.
+// A regexp is made at the end which joins each array with an
+// escaped /, and another full one which joins each regexp with |.
+//
+// Following the lead of Bash 4.1, note that "**" only has special meaning
+// when it is the *only* thing in a path portion.  Otherwise, any series
+// of * is equivalent to a single *.  Globstar behavior is enabled by
+// default, and can be disabled by setting options.noglobstar.
+Minimatch.prototype.parse = parse
+var SUBPARSE = {}
+function parse (pattern, isSub) {
+  assertValidPattern(pattern)
+
+  var options = this.options
+
+  // shortcuts
+  if (pattern === '**') {
+    if (!options.noglobstar)
+      return GLOBSTAR
+    else
+      pattern = '*'
+  }
+  if (pattern === '') return ''
+
+  var re = ''
+  var hasMagic = !!options.nocase
+  var escaping = false
+  // ? => one single character
+  var patternListStack = []
+  var negativeLists = []
+  var stateChar
+  var inClass = false
+  var reClassStart = -1
+  var classStart = -1
+  // . and .. never match anything that doesn't start with .,
+  // even when options.dot is set.
+  var patternStart = pattern.charAt(0) === '.' ? '' // anything
+  // not (start or / followed by . or .. followed by / or end)
+  : options.dot ? '(?!(?:^|\\\/)\\.{1,2}(?:$|\\\/))'
+  : '(?!\\.)'
+  var self = this
+
+  function clearStateChar () {
+    if (stateChar) {
+      // we had some state-tracking character
+      // that wasn't consumed by this pass.
+      switch (stateChar) {
+        case '*':
+          re += star
+          hasMagic = true
+        break
+        case '?':
+          re += qmark
+          hasMagic = true
+        break
+        default:
+          re += '\\' + stateChar
+        break
+      }
+      self.debug('clearStateChar %j %j', stateChar, re)
+      stateChar = false
+    }
+  }
+
+  for (var i = 0, len = pattern.length, c
+    ; (i < len) && (c = pattern.charAt(i))
+    ; i++) {
+    this.debug('%s\t%s %s %j', pattern, i, re, c)
+
+    // skip over any that are escaped.
+    if (escaping && reSpecials[c]) {
+      re += '\\' + c
+      escaping = false
+      continue
+    }
+
+    switch (c) {
+      /* istanbul ignore next */
+      case '/': {
+        // completely not allowed, even escaped.
+        // Should already be path-split by now.
+        return false
+      }
+
+      case '\\':
+        clearStateChar()
+        escaping = true
+      continue
+
+      // the various stateChar values
+      // for the "extglob" stuff.
+      case '?':
+      case '*':
+      case '+':
+      case '@':
+      case '!':
+        this.debug('%s\t%s %s %j <-- stateChar', pattern, i, re, c)
+
+        // all of those are literals inside a class, except that
+        // the glob [!a] means [^a] in regexp
+        if (inClass) {
+          this.debug('  in class')
+          if (c === '!' && i === classStart + 1) c = '^'
+          re += c
+          continue
+        }
+
+        // if we already have a stateChar, then it means
+        // that there was something like ** or +? in there.
+        // Handle the stateChar, then proceed with this one.
+        self.debug('call clearStateChar %j', stateChar)
+        clearStateChar()
+        stateChar = c
+        // if extglob is disabled, then +(asdf|foo) isn't a thing.
+        // just clear the statechar *now*, rather than even diving into
+        // the patternList stuff.
+        if (options.noext) clearStateChar()
+      continue
+
+      case '(':
+        if (inClass) {
+          re += '('
+          continue
+        }
+
+        if (!stateChar) {
+          re += '\$'
+          continue
+        }
+
+        patternListStack.push({
+          type: stateChar,
+          start: i - 1,
+          reStart: re.length,
+          open: plTypes[stateChar].open,
+          close: plTypes[stateChar].close
+        })
+        // negation is (?:(?!js)[^/]*)
+        re += stateChar === '!' ? '(?:(?!(?:' : '(?:'
+        this.debug('plType %j %j', stateChar, re)
+        stateChar = false
+      continue
+
+      case ')':
+        if (inClass || !patternListStack.length) {
+          re += '\$'
+          continue
+        }
+
+        clearStateChar()
+        hasMagic = true
+        var pl = patternListStack.pop()
+        // negation is (?:(?!js)[^/]*)
+        // The others are (?:<pattern>)<type>
+        re += pl.close
+        if (pl.type === '!') {
+          negativeLists.push(pl)
+        }
+        pl.reEnd = re.length
+      continue
+
+      case '|':
+        if (inClass || !patternListStack.length || escaping) {
+          re += '\\|'
+          escaping = false
+          continue
+        }
+
+        clearStateChar()
+        re += '|'
+      continue
+
+      // these are mostly the same in regexp and glob
+      case '[':
+        // swallow any state-tracking char before the [
+        clearStateChar()
+
+        if (inClass) {
+          re += '\\' + c
+          continue
+        }
+
+        inClass = true
+        classStart = i
+        reClassStart = re.length
+        re += c
+      continue
+
+      case ']':
+        //  a right bracket shall lose its special
+        //  meaning and represent itself in
+        //  a bracket expression if it occurs
+        //  first in the list.  -- POSIX.2 2.8.3.2
+        if (i === classStart + 1 || !inClass) {
+          re += '\\' + c
+          escaping = false
+          continue
+        }
+
+        // handle the case where we left a class open.
+        // "[z-a]" is valid, equivalent to "\[z-a\]"
+        // split where the last [ was, make sure we don't have
+        // an invalid re. if so, re-walk the contents of the
+        // would-be class to re-translate any characters that
+        // were passed through as-is
+        // TODO: It would probably be faster to determine this
+        // without a try/catch and a new RegExp, but it's tricky
+        // to do safely.  For now, this is safe and works.
+        var cs = pattern.substring(classStart + 1, i)
+        try {
+          RegExp('[' + cs + ']')
+        } catch (er) {
+          // not a valid class!
+          var sp = this.parse(cs, SUBPARSE)
+          re = re.substr(0, reClassStart) + '\\[' + sp[0] + '\\]'
+          hasMagic = hasMagic || sp[1]
+          inClass = false
+          continue
+        }
+
+        // finish up the class.
+        hasMagic = true
+        inClass = false
+        re += c
+      continue
+
+      default:
+        // swallow any state char that wasn't consumed
+        clearStateChar()
+
+        if (escaping) {
+          // no need
+          escaping = false
+        } else if (reSpecials[c]
+          && !(c === '^' && inClass)) {
+          re += '\\'
+        }
+
+        re += c
+
+    } // switch
+  } // for
+
+  // handle the case where we left a class open.
+  // "[abc" is valid, equivalent to "\[abc"
+  if (inClass) {
+    // split where the last [ was, and escape it
+    // this is a huge pita.  We now have to re-walk
+    // the contents of the would-be class to re-translate
+    // any characters that were passed through as-is
+    cs = pattern.substr(classStart + 1)
+    sp = this.parse(cs, SUBPARSE)
+    re = re.substr(0, reClassStart) + '\\[' + sp[0]
+    hasMagic = hasMagic || sp[1]
+  }
+
+  // handle the case where we had a +( thing at the *end*
+  // of the pattern.
+  // each pattern list stack adds 3 chars, and we need to go through
+  // and escape any | chars that were passed through as-is for the regexp.
+  // Go through and escape them, taking care not to double-escape any
+  // | chars that were already escaped.
+  for (pl = patternListStack.pop(); pl; pl = patternListStack.pop()) {
+    var tail = re.slice(pl.reStart + pl.open.length)
+    this.debug('setting tail', re, pl)
+    // maybe some even number of \, then maybe 1 \, followed by a |
+    tail = tail.replace(/((?:\\{2}){0,64})(\\?)\|/g, function (_, $1, $2) {
+      if (!$2) {
+        // the | isn't already escaped, so escape it.
+        $2 = '\\'
+      }
+
+      // need to escape all those slashes *again*, without escaping the
+      // one that we need for escaping the | character.  As it works out,
+      // escaping an even number of slashes can be done by simply repeating
+      // it exactly after itself.  That's why this trick works.
+      //
+      // I am sorry that you have to see this.
+      return $1 + $1 + $2 + '|'
+    })
+
+    this.debug('tail=%j\n   %s', tail, tail, pl, re)
+    var t = pl.type === '*' ? star
+      : pl.type === '?' ? qmark
+      : '\\' + pl.type
+
+    hasMagic = true
+    re = re.slice(0, pl.reStart) + t + '\\(' + tail
+  }
+
+  // handle trailing things that only matter at the very end.
+  clearStateChar()
+  if (escaping) {
+    // trailing \\
+    re += '\\\\'
+  }
+
+  // only need to apply the nodot start if the re starts with
+  // something that could conceivably capture a dot
+  var addPatternStart = false
+  switch (re.charAt(0)) {
+    case '[': case '.': case '(': addPatternStart = true
+  }
+
+  // Hack to work around lack of negative lookbehind in JS
+  // A pattern like: *.!(x).!(y|z) needs to ensure that a name
+  // like 'a.xyz.yz' doesn't match.  So, the first negative
+  // lookahead, has to look ALL the way ahead, to the end of
+  // the pattern.
+  for (var n = negativeLists.length - 1; n > -1; n--) {
+    var nl = negativeLists[n]
+
+    var nlBefore = re.slice(0, nl.reStart)
+    var nlFirst = re.slice(nl.reStart, nl.reEnd - 8)
+    var nlLast = re.slice(nl.reEnd - 8, nl.reEnd)
+    var nlAfter = re.slice(nl.reEnd)
+
+    nlLast += nlAfter
+
+    // Handle nested stuff like *(*.js|!(*.json)), where open parens
+    // mean that we should *not* include the ) in the bit that is considered
+    // "after" the negated section.
+    var openParensBefore = nlBefore.split('(').length - 1
+    var cleanAfter = nlAfter
+    for (i = 0; i < openParensBefore; i++) {
+      cleanAfter = cleanAfter.replace(/\)[+*?]?/, '')
+    }
+    nlAfter = cleanAfter
+
+    var dollar = ''
+    if (nlAfter === '' && isSub !== SUBPARSE) {
+      dollar = '$'
+    }
+    var newRe = nlBefore + nlFirst + nlAfter + dollar + nlLast
+    re = newRe
+  }
+
+  // if the re is not "" at this point, then we need to make sure
+  // it doesn't match against an empty path part.
+  // Otherwise a/* will match a/, which it should not.
+  if (re !== '' && hasMagic) {
+    re = '(?=.)' + re
+  }
+
+  if (addPatternStart) {
+    re = patternStart + re
+  }
+
+  // parsing just a piece of a larger pattern.
+  if (isSub === SUBPARSE) {
+    return [re, hasMagic]
+  }
+
+  // skip the regexp for non-magical patterns
+  // unescape anything in it, though, so that it'll be
+  // an exact match against a file etc.
+  if (!hasMagic) {
+    return globUnescape(pattern)
+  }
+
+  var flags = options.nocase ? 'i' : ''
+  try {
+    var regExp = new RegExp('^' + re + '$', flags)
+  } catch (er) /* istanbul ignore next - should be impossible */ {
+    // If it was an invalid regular expression, then it can't match
+    // anything.  This trick looks for a character after the end of
+    // the string, which is of course impossible, except in multi-line
+    // mode, but it's not a /m regex.
+    return new RegExp('$.')
+  }
+
+  regExp._glob = pattern
+  regExp._src = re
+
+  return regExp
+}
+
+minimatch.makeRe = function (pattern, options) {
+  return new Minimatch(pattern, options || {}).makeRe()
+}
+
+Minimatch.prototype.makeRe = makeRe
+function makeRe () {
+  if (this.regexp || this.regexp === false) return this.regexp
+
+  // at this point, this.set is a 2d array of partial
+  // pattern strings, or "**".
+  //
+  // It's better to use .match().  This function shouldn't
+  // be used, really, but it's pretty convenient sometimes,
+  // when you just want to work with a regex.
+  var set = this.set
+
+  if (!set.length) {
+    this.regexp = false
+    return this.regexp
+  }
+  var options = this.options
+
+  var twoStar = options.noglobstar ? star
+    : options.dot ? twoStarDot
+    : twoStarNoDot
+  var flags = options.nocase ? 'i' : ''
+
+  var re = set.map(function (pattern) {
+    return pattern.map(function (p) {
+      return (p === GLOBSTAR) ? twoStar
+      : (typeof p === 'string') ? regExpEscape(p)
+      : p._src
+    }).join('\\\/')
+  }).join('|')
+
+  // must match entire pattern
+  // ending in a * or ** will make it less strict.
+  re = '^(?:' + re + ')$'
+
+  // can match anything, as long as it's not this.
+  if (this.negate) re = '^(?!' + re + ').*$'
+
+  try {
+    this.regexp = new RegExp(re, flags)
+  } catch (ex) /* istanbul ignore next - should be impossible */ {
+    this.regexp = false
+  }
+  return this.regexp
+}
+
+minimatch.match = function (list, pattern, options) {
+  options = options || {}
+  var mm = new Minimatch(pattern, options)
+  list = list.filter(function (f) {
+    return mm.match(f)
+  })
+  if (mm.options.nonull && !list.length) {
+    list.push(pattern)
+  }
+  return list
+}
+
+Minimatch.prototype.match = function match (f, partial) {
+  if (typeof partial === 'undefined') partial = this.partial
+  this.debug('match', f, this.pattern)
+  // short-circuit in the case of busted things.
+  // comments, etc.
+  if (this.comment) return false
+  if (this.empty) return f === ''
+
+  if (f === '/' && partial) return true
+
+  var options = this.options
+
+  // windows: need to use /, not \
+  if (path.sep !== '/') {
+    f = f.split(path.sep).join('/')
+  }
+
+  // treat the test path as a set of pathparts.
+  f = f.split(slashSplit)
+  this.debug(this.pattern, 'split', f)
+
+  // just ONE of the pattern sets in this.set needs to match
+  // in order for it to be valid.  If negating, then just one
+  // match means that we have failed.
+  // Either way, return on the first hit.
+
+  var set = this.set
+  this.debug(this.pattern, 'set', set)
+
+  // Find the basename of the path by looking for the last non-empty segment
+  var filename
+  var i
+  for (i = f.length - 1; i >= 0; i--) {
+    filename = f[i]
+    if (filename) break
+  }
+
+  for (i = 0; i < set.length; i++) {
+    var pattern = set[i]
+    var file = f
+    if (options.matchBase && pattern.length === 1) {
+      file = [filename]
+    }
+    var hit = this.matchOne(file, pattern, partial)
+    if (hit) {
+      if (options.flipNegate) return true
+      return !this.negate
+    }
+  }
+
+  // didn't get any hits.  this is success if it's a negative
+  // pattern, failure otherwise.
+  if (options.flipNegate) return false
+  return this.negate
+}
+
+// set partial to true to test if, for example,
+// "/a/b" matches the start of "/*/b/*/d"
+// Partial means, if you run out of file before you run
+// out of pattern, then that's fine, as long as all
+// the parts match.
+Minimatch.prototype.matchOne = function (file, pattern, partial) {
+  var options = this.options
+
+  this.debug('matchOne',
+    { 'this': this, file: file, pattern: pattern })
+
+  this.debug('matchOne', file.length, pattern.length)
+
+  for (var fi = 0,
+      pi = 0,
+      fl = file.length,
+      pl = pattern.length
+      ; (fi < fl) && (pi < pl)
+      ; fi++, pi++) {
+    this.debug('matchOne loop')
+    var p = pattern[pi]
+    var f = file[fi]
+
+    this.debug(pattern, p, f)
+
+    // should be impossible.
+    // some invalid regexp stuff in the set.
+    /* istanbul ignore if */
+    if (p === false) return false
+
+    if (p === GLOBSTAR) {
+      this.debug('GLOBSTAR', [pattern, p, f])
+
+      // "**"
+      // a/**/b/**/c would match the following:
+      // a/b/x/y/z/c
+      // a/x/y/z/b/c
+      // a/b/x/b/x/c
+      // a/b/c
+      // To do this, take the rest of the pattern after
+      // the **, and see if it would match the file remainder.
+      // If so, return success.
+      // If not, the ** "swallows" a segment, and try again.
+      // This is recursively awful.
+      //
+      // a/**/b/**/c matching a/b/x/y/z/c
+      // - a matches a
+      // - doublestar
+      //   - matchOne(b/x/y/z/c, b/**/c)
+      //     - b matches b
+      //     - doublestar
+      //       - matchOne(x/y/z/c, c) -> no
+      //       - matchOne(y/z/c, c) -> no
+      //       - matchOne(z/c, c) -> no
+      //       - matchOne(c, c) yes, hit
+      var fr = fi
+      var pr = pi + 1
+      if (pr === pl) {
+        this.debug('** at the end')
+        // a ** at the end will just swallow the rest.
+        // We have found a match.
+        // however, it will not swallow /.x, unless
+        // options.dot is set.
+        // . and .. are *never* matched by **, for explosively
+        // exponential reasons.
+        for (; fi < fl; fi++) {
+          if (file[fi] === '.' || file[fi] === '..' ||
+            (!options.dot && file[fi].charAt(0) === '.')) return false
+        }
+        return true
+      }
+
+      // ok, let's see if we can swallow whatever we can.
+      while (fr < fl) {
+        var swallowee = file[fr]
+
+        this.debug('\nglobstar while', file, fr, pattern, pr, swallowee)
+
+        // XXX remove this slice.  Just pass the start index.
+        if (this.matchOne(file.slice(fr), pattern.slice(pr), partial)) {
+          this.debug('globstar found match!', fr, fl, swallowee)
+          // found a match.
+          return true
+        } else {
+          // can't swallow "." or ".." ever.
+          // can only swallow ".foo" when explicitly asked.
+          if (swallowee === '.' || swallowee === '..' ||
+            (!options.dot && swallowee.charAt(0) === '.')) {
+            this.debug('dot detected!', file, fr, pattern, pr)
+            break
+          }
+
+          // ** swallows a segment, and continue.
+          this.debug('globstar swallow a segment, and continue')
+          fr++
+        }
+      }
+
+      // no match was found.
+      // However, in partial mode, we can't say this is necessarily over.
+      // If there's more *pattern* left, then
+      /* istanbul ignore if */
+      if (partial) {
+        // ran out of file
+        this.debug('\n>>> no match, partial?', file, fr, pattern, pr)
+        if (fr === fl) return true
+      }
+      return false
+    }
+
+    // something other than **
+    // non-magic patterns just have to match exactly
+    // patterns with magic have been turned into regexps.
+    var hit
+    if (typeof p === 'string') {
+      hit = f === p
+      this.debug('string match', p, f, hit)
+    } else {
+      hit = f.match(p)
+      this.debug('pattern match', p, f, hit)
+    }
+
+    if (!hit) return false
+  }
+
+  // Note: ending in / means that we'll get a final ""
+  // at the end of the pattern.  This can only match a
+  // corresponding "" at the end of the file.
+  // If the file ends in /, then it can only match a
+  // a pattern that ends in /, unless the pattern just
+  // doesn't have any more for it. But, a/b/ should *not*
+  // match "a/b/*", even though "" matches against the
+  // [^/]*? pattern, except in partial mode, where it might
+  // simply not be reached yet.
+  // However, a/b/ should still satisfy a/*
+
+  // now either we fell off the end of the pattern, or we're done.
+  if (fi === fl && pi === pl) {
+    // ran out of pattern and filename at the same time.
+    // an exact hit!
+    return true
+  } else if (fi === fl) {
+    // ran out of file, but still had pattern left.
+    // this is ok if we're doing the match as part of
+    // a glob fs traversal.
+    return partial
+  } else /* istanbul ignore else */ if (pi === pl) {
+    // ran out of pattern, still have file left.
+    // this is only acceptable if we're on the very last
+    // empty segment of a file with a trailing slash.
+    // a/* should match a/b/
+    return (fi === fl - 1) && (file[fi] === '')
+  }
+
+  // should be unreachable.
+  /* istanbul ignore next */
+  throw new Error('wtf?')
+}
+
+// replace stuff like \* with *
+function globUnescape (s) {
+  return s.replace(/\\(.)/g, '$1')
+}
+
+function regExpEscape (s) {
+  return s.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, '\\$&')
+}
diff --git a/server/node_modules/minimatch/package.json b/server/node_modules/minimatch/package.json
new file mode 100644
index 0000000..566efdf
--- /dev/null
+++ b/server/node_modules/minimatch/package.json
@@ -0,0 +1,33 @@
+{
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me)",
+  "name": "minimatch",
+  "description": "a glob matcher in javascript",
+  "version": "3.1.2",
+  "publishConfig": {
+    "tag": "v3-legacy"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/isaacs/minimatch.git"
+  },
+  "main": "minimatch.js",
+  "scripts": {
+    "test": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --all; git push origin --tags"
+  },
+  "engines": {
+    "node": "*"
+  },
+  "dependencies": {
+    "brace-expansion": "^1.1.7"
+  },
+  "devDependencies": {
+    "tap": "^15.1.6"
+  },
+  "license": "ISC",
+  "files": [
+    "minimatch.js"
+  ]
+}
diff --git a/server/node_modules/minimist/.eslintrc b/server/node_modules/minimist/.eslintrc
new file mode 100644
index 0000000..bd1a5e0
--- /dev/null
+++ b/server/node_modules/minimist/.eslintrc
@@ -0,0 +1,29 @@
+{
+	"root": true,
+
+	"extends": "@ljharb/eslint-config/node/0.4",
+
+	"rules": {
+		"array-element-newline": 0,
+		"complexity": 0,
+		"func-style": [2, "declaration"],
+		"max-lines-per-function": 0,
+		"max-nested-callbacks": 1,
+		"max-statements-per-line": 1,
+		"max-statements": 0,
+		"multiline-comment-style": 0,
+		"no-continue": 1,
+		"no-param-reassign": 1,
+		"no-restricted-syntax": 1,
+		"object-curly-newline": 0,
+	},
+
+	"overrides": [
+		{
+			"files": "test/**",
+			"rules": {
+				"camelcase": 0,
+			},
+		},
+	]
+}
diff --git a/server/node_modules/minimist/.github/FUNDING.yml b/server/node_modules/minimist/.github/FUNDING.yml
new file mode 100644
index 0000000..a936622
--- /dev/null
+++ b/server/node_modules/minimist/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/minimist
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/minimist/.nycrc b/server/node_modules/minimist/.nycrc
new file mode 100644
index 0000000..55c3d29
--- /dev/null
+++ b/server/node_modules/minimist/.nycrc
@@ -0,0 +1,14 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"lines": 86,
+	"statements": 85.93,
+	"functions": 82.43,
+	"branches": 76.06,
+	"exclude": [
+		"coverage",
+		"example",
+		"test"
+	]
+}
diff --git a/server/node_modules/minimist/CHANGELOG.md b/server/node_modules/minimist/CHANGELOG.md
new file mode 100644
index 0000000..c9a1e15
--- /dev/null
+++ b/server/node_modules/minimist/CHANGELOG.md
@@ -0,0 +1,298 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.2.8](https://github.com/minimistjs/minimist/compare/v1.2.7...v1.2.8) - 2023-02-09
+
+### Merged
+
+- [Fix] Fix long option followed by single dash [`#17`](https://github.com/minimistjs/minimist/pull/17)
+- [Tests] Remove duplicate test [`#12`](https://github.com/minimistjs/minimist/pull/12)
+- [Fix] opt.string works with multiple aliases [`#10`](https://github.com/minimistjs/minimist/pull/10)
+
+### Fixed
+
+- [Fix] Fix long option followed by single dash (#17) [`#15`](https://github.com/minimistjs/minimist/issues/15)
+- [Tests] Remove duplicate test (#12) [`#8`](https://github.com/minimistjs/minimist/issues/8)
+- [Fix] Fix long option followed by single dash [`#15`](https://github.com/minimistjs/minimist/issues/15)
+- [Fix] opt.string works with multiple aliases (#10) [`#9`](https://github.com/minimistjs/minimist/issues/9)
+- [Fix] Fix handling of short option with non-trivial equals [`#5`](https://github.com/minimistjs/minimist/issues/5)
+- [Tests] Remove duplicate test [`#8`](https://github.com/minimistjs/minimist/issues/8)
+- [Fix] opt.string works with multiple aliases [`#9`](https://github.com/minimistjs/minimist/issues/9)
+
+### Commits
+
+- Merge tag 'v0.2.3' [`a026794`](https://github.com/minimistjs/minimist/commit/a0267947c7870fc5847cf2d437fbe33f392767da)
+- [eslint] fix indentation and whitespace [`5368ca4`](https://github.com/minimistjs/minimist/commit/5368ca4147e974138a54cc0dc4cea8f756546b70)
+- [eslint] fix indentation and whitespace [`e5f5067`](https://github.com/minimistjs/minimist/commit/e5f5067259ceeaf0b098d14bec910f87e58708c7)
+- [eslint] more cleanup [`62fde7d`](https://github.com/minimistjs/minimist/commit/62fde7d935f83417fb046741531a9e2346a36976)
+- [eslint] more cleanup [`36ac5d0`](https://github.com/minimistjs/minimist/commit/36ac5d0d95e4947d074e5737d94814034ca335d1)
+- [meta] add `auto-changelog` [`73923d2`](https://github.com/minimistjs/minimist/commit/73923d223553fca08b1ba77e3fbc2a492862ae4c)
+- [actions] add reusable workflows [`d80727d`](https://github.com/minimistjs/minimist/commit/d80727df77bfa9e631044d7f16368d8f09242c91)
+- [eslint] add eslint; rules to enable later are warnings [`48bc06a`](https://github.com/minimistjs/minimist/commit/48bc06a1b41f00e9cdf183db34f7a51ba70e98d4)
+- [eslint] fix indentation [`34b0f1c`](https://github.com/minimistjs/minimist/commit/34b0f1ccaa45183c3c4f06a91f9b405180a6f982)
+- [readme] rename and add badges [`5df0fe4`](https://github.com/minimistjs/minimist/commit/5df0fe49211bd09a3636f8686a7cb3012c3e98f0)
+- [Dev Deps] switch from `covert` to `nyc` [`a48b128`](https://github.com/minimistjs/minimist/commit/a48b128fdb8d427dfb20a15273f83e38d97bef07)
+- [Dev Deps] update `covert`, `tape`; remove unnecessary `tap` [`f0fb958`](https://github.com/minimistjs/minimist/commit/f0fb958e9a1fe980cdffc436a211b0bda58f621b)
+- [meta] create FUNDING.yml; add `funding` in package.json [`3639e0c`](https://github.com/minimistjs/minimist/commit/3639e0c819359a366387e425ab6eabf4c78d3caa)
+- [meta] use `npmignore` to autogenerate an npmignore file [`be2e038`](https://github.com/minimistjs/minimist/commit/be2e038c342d8333b32f0fde67a0026b79c8150e)
+- Only apps should have lockfiles [`282b570`](https://github.com/minimistjs/minimist/commit/282b570e7489d01b03f2d6d3dabf79cd3e5f84cf)
+- isConstructorOrProto adapted from PR [`ef9153f`](https://github.com/minimistjs/minimist/commit/ef9153fc52b6cea0744b2239921c5dcae4697f11)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud` [`098873c`](https://github.com/minimistjs/minimist/commit/098873c213cdb7c92e55ae1ef5aa1af3a8192a79)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud` [`3124ed3`](https://github.com/minimistjs/minimist/commit/3124ed3e46306301ebb3c834874ce0241555c2c4)
+- [meta] add `safe-publish-latest` [`4b927de`](https://github.com/minimistjs/minimist/commit/4b927de696d561c636b4f43bf49d4597cb36d6d6)
+- [Tests] add `aud` in `posttest` [`b32d9bd`](https://github.com/minimistjs/minimist/commit/b32d9bd0ab340f4e9f8c3a97ff2a4424f25fab8c)
+- [meta] update repo URLs [`f9fdfc0`](https://github.com/minimistjs/minimist/commit/f9fdfc032c54884d9a9996a390c63cd0719bbe1a)
+- [actions] Avoid 0.6 tests due to build failures [`ba92fe6`](https://github.com/minimistjs/minimist/commit/ba92fe6ebbdc0431cca9a2ea8f27beb492f5e4ec)
+- [Dev Deps] update `tape` [`950eaa7`](https://github.com/minimistjs/minimist/commit/950eaa74f112e04d23e9c606c67472c46739b473)
+- [Dev Deps] add missing `npmignore` dev dep [`3226afa`](https://github.com/minimistjs/minimist/commit/3226afaf09e9d127ca369742437fe6e88f752d6b)
+- Merge tag 'v0.2.2' [`980d7ac`](https://github.com/minimistjs/minimist/commit/980d7ac61a0b4bd552711251ac107d506b23e41f)
+
+## [v1.2.7](https://github.com/minimistjs/minimist/compare/v1.2.6...v1.2.7) - 2022-10-10
+
+### Commits
+
+- [meta] add `auto-changelog` [`0ebf4eb`](https://github.com/minimistjs/minimist/commit/0ebf4ebcd5f7787a5524d31a849ef41316b83c3c)
+- [actions] add reusable workflows [`e115b63`](https://github.com/minimistjs/minimist/commit/e115b63fa9d3909f33b00a2db647ff79068388de)
+- [eslint] add eslint; rules to enable later are warnings [`f58745b`](https://github.com/minimistjs/minimist/commit/f58745b9bb84348e1be72af7dbba5840c7c13013)
+- [Dev Deps] switch from `covert` to `nyc` [`ab03356`](https://github.com/minimistjs/minimist/commit/ab033567b9c8b31117cb026dc7f1e592ce455c65)
+- [readme] rename and add badges [`236f4a0`](https://github.com/minimistjs/minimist/commit/236f4a07e4ebe5ee44f1496ec6974991ab293ffd)
+- [meta] create FUNDING.yml; add `funding` in package.json [`783a49b`](https://github.com/minimistjs/minimist/commit/783a49bfd47e8335d3098a8cac75662cf71eb32a)
+- [meta] use `npmignore` to autogenerate an npmignore file [`f81ece6`](https://github.com/minimistjs/minimist/commit/f81ece6aaec2fa14e69ff4f1e0407a8c4e2635a2)
+- Only apps should have lockfiles [`56cad44`](https://github.com/minimistjs/minimist/commit/56cad44c7f879b9bb5ec18fcc349308024a89bfc)
+- [Dev Deps] update `covert`, `tape`; remove unnecessary `tap` [`49c5f9f`](https://github.com/minimistjs/minimist/commit/49c5f9fb7e6a92db9eb340cc679de92fb3aacded)
+- [Tests] add `aud` in `posttest` [`228ae93`](https://github.com/minimistjs/minimist/commit/228ae938f3cd9db9dfd8bd7458b076a7b2aef280)
+- [meta] add `safe-publish-latest` [`01fc23f`](https://github.com/minimistjs/minimist/commit/01fc23f5104f85c75059972e01dd33796ab529ff)
+- [meta] update repo URLs [`6b164c7`](https://github.com/minimistjs/minimist/commit/6b164c7d68e0b6bf32f894699effdfb7c63041dd)
+
+## [v1.2.6](https://github.com/minimistjs/minimist/compare/v1.2.5...v1.2.6) - 2022-03-21
+
+### Commits
+
+- test from prototype pollution PR [`bc8ecee`](https://github.com/minimistjs/minimist/commit/bc8ecee43875261f4f17eb20b1243d3ed15e70eb)
+- isConstructorOrProto adapted from PR [`c2b9819`](https://github.com/minimistjs/minimist/commit/c2b981977fa834b223b408cfb860f933c9811e4d)
+- security notice for additional prototype pollution issue [`ef88b93`](https://github.com/minimistjs/minimist/commit/ef88b9325f77b5ee643ccfc97e2ebda577e4c4e2)
+
+## [v1.2.5](https://github.com/minimistjs/minimist/compare/v1.2.4...v1.2.5) - 2020-03-12
+
+## [v1.2.4](https://github.com/minimistjs/minimist/compare/v1.2.3...v1.2.4) - 2020-03-11
+
+### Commits
+
+- security notice [`4cf1354`](https://github.com/minimistjs/minimist/commit/4cf1354839cb972e38496d35e12f806eea92c11f)
+- additional test for constructor prototype pollution [`1043d21`](https://github.com/minimistjs/minimist/commit/1043d212c3caaf871966e710f52cfdf02f9eea4b)
+
+## [v1.2.3](https://github.com/minimistjs/minimist/compare/v1.2.2...v1.2.3) - 2020-03-10
+
+### Commits
+
+- more failing proto pollution tests [`13c01a5`](https://github.com/minimistjs/minimist/commit/13c01a5327736903704984b7f65616b8476850cc)
+- even more aggressive checks for protocol pollution [`38a4d1c`](https://github.com/minimistjs/minimist/commit/38a4d1caead72ef99e824bb420a2528eec03d9ab)
+
+## [v1.2.2](https://github.com/minimistjs/minimist/compare/v1.2.1...v1.2.2) - 2020-03-10
+
+### Commits
+
+- failing test for protocol pollution [`0efed03`](https://github.com/minimistjs/minimist/commit/0efed0340ec8433638758f7ca0c77cb20a0bfbab)
+- cleanup [`67d3722`](https://github.com/minimistjs/minimist/commit/67d3722413448d00a62963d2d30c34656a92d7e2)
+- console.dir -> console.log [`47acf72`](https://github.com/minimistjs/minimist/commit/47acf72c715a630bf9ea013867f47f1dd69dfc54)
+- don't assign onto __proto__ [`63e7ed0`](https://github.com/minimistjs/minimist/commit/63e7ed05aa4b1889ec2f3b196426db4500cbda94)
+
+## [v1.2.1](https://github.com/minimistjs/minimist/compare/v1.2.0...v1.2.1) - 2020-03-10
+
+### Merged
+
+- move the `opts['--']` example back where it belongs [`#63`](https://github.com/minimistjs/minimist/pull/63)
+
+### Commits
+
+- add test [`6be5dae`](https://github.com/minimistjs/minimist/commit/6be5dae35a32a987bcf4137fcd6c19c5200ee909)
+- fix bad boolean regexp [`ac3fc79`](https://github.com/minimistjs/minimist/commit/ac3fc796e63b95128fdbdf67ea7fad71bd59aa76)
+
+## [v1.2.0](https://github.com/minimistjs/minimist/compare/v1.1.3...v1.2.0) - 2015-08-24
+
+### Commits
+
+- failing -k=v short test [`63416b8`](https://github.com/minimistjs/minimist/commit/63416b8cd1d0d70e4714564cce465a36e4dd26d7)
+- kv short fix [`6bbe145`](https://github.com/minimistjs/minimist/commit/6bbe14529166245e86424f220a2321442fe88dc3)
+- failing kv short test [`f72ab7f`](https://github.com/minimistjs/minimist/commit/f72ab7f4572adc52902c9b6873cc969192f01b10)
+- fixed kv test [`f5a48c3`](https://github.com/minimistjs/minimist/commit/f5a48c3e50e40ca54f00c8e84de4b4d6e9897fa8)
+- enforce space between arg key and value [`86b321a`](https://github.com/minimistjs/minimist/commit/86b321affe648a8e016c095a4f0efa9d9074f502)
+
+## [v1.1.3](https://github.com/minimistjs/minimist/compare/v1.1.2...v1.1.3) - 2015-08-06
+
+### Commits
+
+- add failing test - boolean alias array [`0fa3c5b`](https://github.com/minimistjs/minimist/commit/0fa3c5b3dd98551ddecf5392831b4c21211743fc)
+- fix boolean values with multiple aliases [`9c0a6e7`](https://github.com/minimistjs/minimist/commit/9c0a6e7de25a273b11bbf9a7464f0bd833779795)
+
+## [v1.1.2](https://github.com/minimistjs/minimist/compare/v1.1.1...v1.1.2) - 2015-07-22
+
+### Commits
+
+- Convert boolean arguments to boolean values [`8f3dc27`](https://github.com/minimistjs/minimist/commit/8f3dc27cf833f1d54671b6d0bcb55c2fe19672a9)
+- use non-ancient npm, node 0.12 and iojs [`61ed1d0`](https://github.com/minimistjs/minimist/commit/61ed1d034b9ec7282764ce76f3992b1a0b4906ae)
+- an older npm for 0.8 [`25cf778`](https://github.com/minimistjs/minimist/commit/25cf778b1220e7838a526832ad6972f75244054f)
+
+## [v1.1.1](https://github.com/minimistjs/minimist/compare/v1.1.0...v1.1.1) - 2015-03-10
+
+### Commits
+
+- check that they type of a value is a boolean, not just that it is currently set to a boolean [`6863198`](https://github.com/minimistjs/minimist/commit/6863198e36139830ff1f20ffdceaddd93f2c1db9)
+- upgrade tape, fix type issues from old tape version [`806712d`](https://github.com/minimistjs/minimist/commit/806712df91604ed02b8e39aa372b84aea659ee34)
+- test for setting a boolean to a null default [`8c444fe`](https://github.com/minimistjs/minimist/commit/8c444fe89384ded7d441c120915ea60620b01dd3)
+- if the previous value was a boolean, without an default (or with an alias) don't make an array either [`e5f419a`](https://github.com/minimistjs/minimist/commit/e5f419a3b5b3bc3f9e5ac71b7040621af70ed2dd)
+
+## [v1.1.0](https://github.com/minimistjs/minimist/compare/v1.0.0...v1.1.0) - 2014-08-10
+
+### Commits
+
+- add support for handling "unknown" options not registered with the parser. [`6f3cc5d`](https://github.com/minimistjs/minimist/commit/6f3cc5d4e84524932a6ef2ce3592acc67cdd4383)
+- reformat package.json [`02ed371`](https://github.com/minimistjs/minimist/commit/02ed37115194d3697ff358e8e25e5e66bab1d9f8)
+- coverage script [`e5531ba`](https://github.com/minimistjs/minimist/commit/e5531ba0479da3b8138d3d8cac545d84ccb1c8df)
+- extra fn to get 100% coverage again [`a6972da`](https://github.com/minimistjs/minimist/commit/a6972da89e56bf77642f8ec05a13b6558db93498)
+
+## [v1.0.0](https://github.com/minimistjs/minimist/compare/v0.2.3...v1.0.0) - 2014-08-10
+
+### Commits
+
+- added stopEarly option [`471c7e4`](https://github.com/minimistjs/minimist/commit/471c7e4a7e910fc7ad8f9df850a186daf32c64e9)
+- fix list [`fef6ae7`](https://github.com/minimistjs/minimist/commit/fef6ae79c38b9dc1c49569abb7cd04eb965eac5e)
+
+## [v0.2.3](https://github.com/minimistjs/minimist/compare/v0.2.2...v0.2.3) - 2023-02-09
+
+### Merged
+
+- [Fix] Fix long option followed by single dash [`#17`](https://github.com/minimistjs/minimist/pull/17)
+- [Tests] Remove duplicate test [`#12`](https://github.com/minimistjs/minimist/pull/12)
+- [Fix] opt.string works with multiple aliases [`#10`](https://github.com/minimistjs/minimist/pull/10)
+
+### Fixed
+
+- [Fix] Fix long option followed by single dash (#17) [`#15`](https://github.com/minimistjs/minimist/issues/15)
+- [Tests] Remove duplicate test (#12) [`#8`](https://github.com/minimistjs/minimist/issues/8)
+- [Fix] opt.string works with multiple aliases (#10) [`#9`](https://github.com/minimistjs/minimist/issues/9)
+
+### Commits
+
+- [eslint] fix indentation and whitespace [`e5f5067`](https://github.com/minimistjs/minimist/commit/e5f5067259ceeaf0b098d14bec910f87e58708c7)
+- [eslint] more cleanup [`36ac5d0`](https://github.com/minimistjs/minimist/commit/36ac5d0d95e4947d074e5737d94814034ca335d1)
+- [eslint] fix indentation [`34b0f1c`](https://github.com/minimistjs/minimist/commit/34b0f1ccaa45183c3c4f06a91f9b405180a6f982)
+- isConstructorOrProto adapted from PR [`ef9153f`](https://github.com/minimistjs/minimist/commit/ef9153fc52b6cea0744b2239921c5dcae4697f11)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud` [`098873c`](https://github.com/minimistjs/minimist/commit/098873c213cdb7c92e55ae1ef5aa1af3a8192a79)
+- [Dev Deps] add missing `npmignore` dev dep [`3226afa`](https://github.com/minimistjs/minimist/commit/3226afaf09e9d127ca369742437fe6e88f752d6b)
+
+## [v0.2.2](https://github.com/minimistjs/minimist/compare/v0.2.1...v0.2.2) - 2022-10-10
+
+### Commits
+
+- [meta] add `auto-changelog` [`73923d2`](https://github.com/minimistjs/minimist/commit/73923d223553fca08b1ba77e3fbc2a492862ae4c)
+- [actions] add reusable workflows [`d80727d`](https://github.com/minimistjs/minimist/commit/d80727df77bfa9e631044d7f16368d8f09242c91)
+- [eslint] add eslint; rules to enable later are warnings [`48bc06a`](https://github.com/minimistjs/minimist/commit/48bc06a1b41f00e9cdf183db34f7a51ba70e98d4)
+- [readme] rename and add badges [`5df0fe4`](https://github.com/minimistjs/minimist/commit/5df0fe49211bd09a3636f8686a7cb3012c3e98f0)
+- [Dev Deps] switch from `covert` to `nyc` [`a48b128`](https://github.com/minimistjs/minimist/commit/a48b128fdb8d427dfb20a15273f83e38d97bef07)
+- [Dev Deps] update `covert`, `tape`; remove unnecessary `tap` [`f0fb958`](https://github.com/minimistjs/minimist/commit/f0fb958e9a1fe980cdffc436a211b0bda58f621b)
+- [meta] create FUNDING.yml; add `funding` in package.json [`3639e0c`](https://github.com/minimistjs/minimist/commit/3639e0c819359a366387e425ab6eabf4c78d3caa)
+- [meta] use `npmignore` to autogenerate an npmignore file [`be2e038`](https://github.com/minimistjs/minimist/commit/be2e038c342d8333b32f0fde67a0026b79c8150e)
+- Only apps should have lockfiles [`282b570`](https://github.com/minimistjs/minimist/commit/282b570e7489d01b03f2d6d3dabf79cd3e5f84cf)
+- [meta] add `safe-publish-latest` [`4b927de`](https://github.com/minimistjs/minimist/commit/4b927de696d561c636b4f43bf49d4597cb36d6d6)
+- [Tests] add `aud` in `posttest` [`b32d9bd`](https://github.com/minimistjs/minimist/commit/b32d9bd0ab340f4e9f8c3a97ff2a4424f25fab8c)
+- [meta] update repo URLs [`f9fdfc0`](https://github.com/minimistjs/minimist/commit/f9fdfc032c54884d9a9996a390c63cd0719bbe1a)
+
+## [v0.2.1](https://github.com/minimistjs/minimist/compare/v0.2.0...v0.2.1) - 2020-03-12
+
+## [v0.2.0](https://github.com/minimistjs/minimist/compare/v0.1.0...v0.2.0) - 2014-06-19
+
+### Commits
+
+- support all-boolean mode [`450a97f`](https://github.com/minimistjs/minimist/commit/450a97f6e2bc85c7a4a13185c19a818d9a5ebe69)
+
+## [v0.1.0](https://github.com/minimistjs/minimist/compare/v0.0.10...v0.1.0) - 2014-05-12
+
+### Commits
+
+- Provide a mechanism to segregate -- arguments [`ce4a1e6`](https://github.com/minimistjs/minimist/commit/ce4a1e63a7e8d5ab88d2a3768adefa6af98a445a)
+- documented argv['--'] [`14db0e6`](https://github.com/minimistjs/minimist/commit/14db0e6dbc6d2b9e472adaa54dad7004b364634f)
+- Adding a test-case for notFlags segregation [`715c1e3`](https://github.com/minimistjs/minimist/commit/715c1e3714be223f998f6c537af6b505f0236c16)
+
+## [v0.0.10](https://github.com/minimistjs/minimist/compare/v0.0.9...v0.0.10) - 2014-05-11
+
+### Commits
+
+- dedicated boolean test [`46e448f`](https://github.com/minimistjs/minimist/commit/46e448f9f513cfeb2bcc8b688b9b47ba1e515c2b)
+- dedicated num test [`9bf2d36`](https://github.com/minimistjs/minimist/commit/9bf2d36f1d3b8795be90b8f7de0a937f098aa394)
+- aliased values treated as strings [`1ab743b`](https://github.com/minimistjs/minimist/commit/1ab743bad4484d69f1259bed42f9531de01119de)
+- cover the case of already numbers, at 100% coverage [`b2bb044`](https://github.com/minimistjs/minimist/commit/b2bb04436599d77a2ce029e8e555e25b3aa55d13)
+- another test for higher coverage [`3662624`](https://github.com/minimistjs/minimist/commit/3662624be976d5489d486a856849c048d13be903)
+
+## [v0.0.9](https://github.com/minimistjs/minimist/compare/v0.0.8...v0.0.9) - 2014-05-08
+
+### Commits
+
+- Eliminate `longest` fn. [`824f642`](https://github.com/minimistjs/minimist/commit/824f642038d1b02ede68b6261d1d65163390929a)
+
+## [v0.0.8](https://github.com/minimistjs/minimist/compare/v0.0.7...v0.0.8) - 2014-02-20
+
+### Commits
+
+- return '' if flag is string and empty [`fa63ed4`](https://github.com/minimistjs/minimist/commit/fa63ed4651a4ef4eefddce34188e0d98d745a263)
+- handle joined single letters [`66c248f`](https://github.com/minimistjs/minimist/commit/66c248f0241d4d421d193b022e9e365f11178534)
+
+## [v0.0.7](https://github.com/minimistjs/minimist/compare/v0.0.6...v0.0.7) - 2014-02-08
+
+### Commits
+
+- another swap of .test for .match [`d1da408`](https://github.com/minimistjs/minimist/commit/d1da40819acbe846d89a5c02721211e3c1260dde)
+
+## [v0.0.6](https://github.com/minimistjs/minimist/compare/v0.0.5...v0.0.6) - 2014-02-08
+
+### Commits
+
+- use .test() instead of .match() to not crash on non-string values in the arguments array [`7e0d1ad`](https://github.com/minimistjs/minimist/commit/7e0d1add8c9e5b9b20a4d3d0f9a94d824c578da1)
+
+## [v0.0.5](https://github.com/minimistjs/minimist/compare/v0.0.4...v0.0.5) - 2013-09-18
+
+### Commits
+
+- Improve '--' handling. [`b11822c`](https://github.com/minimistjs/minimist/commit/b11822c09cc9d2460f30384d12afc0b953c037a4)
+
+## [v0.0.4](https://github.com/minimistjs/minimist/compare/v0.0.3...v0.0.4) - 2013-09-17
+
+## [v0.0.3](https://github.com/minimistjs/minimist/compare/v0.0.2...v0.0.3) - 2013-09-12
+
+### Commits
+
+- failing test for single dash preceeding a double dash [`b465514`](https://github.com/minimistjs/minimist/commit/b465514b82c9ae28972d714facd951deb2ad762b)
+- fix for the dot test [`6a095f1`](https://github.com/minimistjs/minimist/commit/6a095f1d364c8fab2d6753d2291a0649315d297a)
+
+## [v0.0.2](https://github.com/minimistjs/minimist/compare/v0.0.1...v0.0.2) - 2013-08-28
+
+### Commits
+
+- allow dotted aliases & defaults [`321c33e`](https://github.com/minimistjs/minimist/commit/321c33e755485faaeb44eeb1c05d33b2e0a5a7c4)
+- use a better version of ff [`e40f611`](https://github.com/minimistjs/minimist/commit/e40f61114cf7be6f7947f7b3eed345853a67dbbb)
+
+## [v0.0.1](https://github.com/minimistjs/minimist/compare/v0.0.0...v0.0.1) - 2013-06-25
+
+### Commits
+
+- remove trailing commas [`6ff0fa0`](https://github.com/minimistjs/minimist/commit/6ff0fa055064f15dbe06d50b89d5173a6796e1db)
+
+## v0.0.0 - 2013-06-25
+
+### Commits
+
+- half of the parse test ported [`3079326`](https://github.com/minimistjs/minimist/commit/307932601325087de6cf94188eb798ffc4f3088a)
+- stripped down code and a passing test from optimist [`7cced88`](https://github.com/minimistjs/minimist/commit/7cced88d82e399d1a03ed23eb667f04d3f320d10)
+- ported parse tests completely over [`9448754`](https://github.com/minimistjs/minimist/commit/944875452e0820df6830b1408c26a0f7d3e1db04)
+- docs, package.json [`a5bf46a`](https://github.com/minimistjs/minimist/commit/a5bf46ac9bb3bd114a9c340276c62c1091e538d5)
+- move more short tests into short.js [`503edb5`](https://github.com/minimistjs/minimist/commit/503edb5c41d89c0d40831ee517154fc13b0f18b9)
+- default bool test was wrong, not the code [`1b9f5db`](https://github.com/minimistjs/minimist/commit/1b9f5db4741b49962846081b68518de824992097)
+- passing long tests ripped out of parse.js [`7972c4a`](https://github.com/minimistjs/minimist/commit/7972c4aff1f4803079e1668006658e2a761a0428)
+- badges [`84c0370`](https://github.com/minimistjs/minimist/commit/84c037063664d42878aace715fe6572ce01b6f3b)
+- all the tests now ported, some failures [`64239ed`](https://github.com/minimistjs/minimist/commit/64239edfe92c711c4eb0da254fcdfad2a5fdb605)
+- failing short test [`f8a5341`](https://github.com/minimistjs/minimist/commit/f8a534112dd1138d2fad722def56a848480c446f)
+- fixed the numeric test [`6b034f3`](https://github.com/minimistjs/minimist/commit/6b034f37c79342c60083ed97fd222e16928aac51)
diff --git a/server/node_modules/minimist/LICENSE b/server/node_modules/minimist/LICENSE
new file mode 100644
index 0000000..ee27ba4
--- /dev/null
+++ b/server/node_modules/minimist/LICENSE
@@ -0,0 +1,18 @@
+This software is released under the MIT license:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/minimist/README.md b/server/node_modules/minimist/README.md
new file mode 100644
index 0000000..74da323
--- /dev/null
+++ b/server/node_modules/minimist/README.md
@@ -0,0 +1,121 @@
+# minimist <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+parse argument options
+
+This module is the guts of optimist's argument parser without all the
+fanciful decoration.
+
+# example
+
+``` js
+var argv = require('minimist')(process.argv.slice(2));
+console.log(argv);
+```
+
+```
+$ node example/parse.js -a beep -b boop
+{ _: [], a: 'beep', b: 'boop' }
+```
+
+```
+$ node example/parse.js -x 3 -y 4 -n5 -abc --beep=boop foo bar baz
+{
+	_: ['foo', 'bar', 'baz'],
+	x: 3,
+	y: 4,
+	n: 5,
+	a: true,
+	b: true,
+	c: true,
+	beep: 'boop'
+}
+```
+
+# security
+
+Previous versions had a prototype pollution bug that could cause privilege
+escalation in some circumstances when handling untrusted user input.
+
+Please use version 1.2.6 or later:
+
+* https://security.snyk.io/vuln/SNYK-JS-MINIMIST-2429795 (version <=1.2.5)
+* https://snyk.io/vuln/SNYK-JS-MINIMIST-559764 (version <=1.2.3)
+
+# methods
+
+``` js
+var parseArgs = require('minimist')
+```
+
+## var argv = parseArgs(args, opts={})
+
+Return an argument object `argv` populated with the array arguments from `args`.
+
+`argv._` contains all the arguments that didn't have an option associated with
+them.
+
+Numeric-looking arguments will be returned as numbers unless `opts.string` or
+`opts.boolean` is set for that argument name.
+
+Any arguments after `'--'` will not be parsed and will end up in `argv._`.
+
+options can be:
+
+* `opts.string` - a string or array of strings argument names to always treat as
+strings
+* `opts.boolean` - a boolean, string or array of strings to always treat as
+booleans. if `true` will treat all double hyphenated arguments without equal signs
+as boolean (e.g. affects `--foo`, not `-f` or `--foo=bar`)
+* `opts.alias` - an object mapping string names to strings or arrays of string
+argument names to use as aliases
+* `opts.default` - an object mapping string argument names to default values
+* `opts.stopEarly` - when true, populate `argv._` with everything after the
+first non-option
+* `opts['--']` - when true, populate `argv._` with everything before the `--`
+and `argv['--']` with everything after the `--`. Here's an example:
+
+  ```
+  > require('./')('one two three -- four five --six'.split(' '), { '--': true })
+  {
+    _: ['one', 'two', 'three'],
+    '--': ['four', 'five', '--six']
+  }
+  ```
+
+  Note that with `opts['--']` set, parsing for arguments still stops after the
+  `--`.
+
+* `opts.unknown` - a function which is invoked with a command line parameter not
+defined in the `opts` configuration object. If the function returns `false`, the
+unknown option is not added to `argv`.
+
+# install
+
+With [npm](https://npmjs.org) do:
+
+```
+npm install minimist
+```
+
+# license
+
+MIT
+
+[package-url]: https://npmjs.org/package/minimist
+[npm-version-svg]: https://versionbadg.es/minimistjs/minimist.svg
+[npm-badge-png]: https://nodei.co/npm/minimist.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/minimist.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/minimist.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=minimist
+[codecov-image]: https://codecov.io/gh/minimistjs/minimist/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/minimistjs/minimist/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/minimistjs/minimist
+[actions-url]: https://github.com/minimistjs/minimist/actions
diff --git a/server/node_modules/minimist/example/parse.js b/server/node_modules/minimist/example/parse.js
new file mode 100644
index 0000000..9d90ffb
--- /dev/null
+++ b/server/node_modules/minimist/example/parse.js
@@ -0,0 +1,4 @@
+'use strict';
+
+var argv = require('../')(process.argv.slice(2));
+console.log(argv);
diff --git a/server/node_modules/minimist/index.js b/server/node_modules/minimist/index.js
new file mode 100644
index 0000000..f020f39
--- /dev/null
+++ b/server/node_modules/minimist/index.js
@@ -0,0 +1,263 @@
+'use strict';
+
+function hasKey(obj, keys) {
+	var o = obj;
+	keys.slice(0, -1).forEach(function (key) {
+		o = o[key] || {};
+	});
+
+	var key = keys[keys.length - 1];
+	return key in o;
+}
+
+function isNumber(x) {
+	if (typeof x === 'number') { return true; }
+	if ((/^0x[0-9a-f]+$/i).test(x)) { return true; }
+	return (/^[-+]?(?:\d+(?:\.\d*)?|\.\d+)(e[-+]?\d+)?$/).test(x);
+}
+
+function isConstructorOrProto(obj, key) {
+	return (key === 'constructor' && typeof obj[key] === 'function') || key === '__proto__';
+}
+
+module.exports = function (args, opts) {
+	if (!opts) { opts = {}; }
+
+	var flags = {
+		bools: {},
+		strings: {},
+		unknownFn: null,
+	};
+
+	if (typeof opts.unknown === 'function') {
+		flags.unknownFn = opts.unknown;
+	}
+
+	if (typeof opts.boolean === 'boolean' && opts.boolean) {
+		flags.allBools = true;
+	} else {
+		[].concat(opts.boolean).filter(Boolean).forEach(function (key) {
+			flags.bools[key] = true;
+		});
+	}
+
+	var aliases = {};
+
+	function aliasIsBoolean(key) {
+		return aliases[key].some(function (x) {
+			return flags.bools[x];
+		});
+	}
+
+	Object.keys(opts.alias || {}).forEach(function (key) {
+		aliases[key] = [].concat(opts.alias[key]);
+		aliases[key].forEach(function (x) {
+			aliases[x] = [key].concat(aliases[key].filter(function (y) {
+				return x !== y;
+			}));
+		});
+	});
+
+	[].concat(opts.string).filter(Boolean).forEach(function (key) {
+		flags.strings[key] = true;
+		if (aliases[key]) {
+			[].concat(aliases[key]).forEach(function (k) {
+				flags.strings[k] = true;
+			});
+		}
+	});
+
+	var defaults = opts.default || {};
+
+	var argv = { _: [] };
+
+	function argDefined(key, arg) {
+		return (flags.allBools && (/^--[^=]+$/).test(arg))
+			|| flags.strings[key]
+			|| flags.bools[key]
+			|| aliases[key];
+	}
+
+	function setKey(obj, keys, value) {
+		var o = obj;
+		for (var i = 0; i < keys.length - 1; i++) {
+			var key = keys[i];
+			if (isConstructorOrProto(o, key)) { return; }
+			if (o[key] === undefined) { o[key] = {}; }
+			if (
+				o[key] === Object.prototype
+				|| o[key] === Number.prototype
+				|| o[key] === String.prototype
+			) {
+				o[key] = {};
+			}
+			if (o[key] === Array.prototype) { o[key] = []; }
+			o = o[key];
+		}
+
+		var lastKey = keys[keys.length - 1];
+		if (isConstructorOrProto(o, lastKey)) { return; }
+		if (
+			o === Object.prototype
+			|| o === Number.prototype
+			|| o === String.prototype
+		) {
+			o = {};
+		}
+		if (o === Array.prototype) { o = []; }
+		if (o[lastKey] === undefined || flags.bools[lastKey] || typeof o[lastKey] === 'boolean') {
+			o[lastKey] = value;
+		} else if (Array.isArray(o[lastKey])) {
+			o[lastKey].push(value);
+		} else {
+			o[lastKey] = [o[lastKey], value];
+		}
+	}
+
+	function setArg(key, val, arg) {
+		if (arg && flags.unknownFn && !argDefined(key, arg)) {
+			if (flags.unknownFn(arg) === false) { return; }
+		}
+
+		var value = !flags.strings[key] && isNumber(val)
+			? Number(val)
+			: val;
+		setKey(argv, key.split('.'), value);
+
+		(aliases[key] || []).forEach(function (x) {
+			setKey(argv, x.split('.'), value);
+		});
+	}
+
+	Object.keys(flags.bools).forEach(function (key) {
+		setArg(key, defaults[key] === undefined ? false : defaults[key]);
+	});
+
+	var notFlags = [];
+
+	if (args.indexOf('--') !== -1) {
+		notFlags = args.slice(args.indexOf('--') + 1);
+		args = args.slice(0, args.indexOf('--'));
+	}
+
+	for (var i = 0; i < args.length; i++) {
+		var arg = args[i];
+		var key;
+		var next;
+
+		if ((/^--.+=/).test(arg)) {
+			// Using [\s\S] instead of . because js doesn't support the
+			// 'dotall' regex modifier. See:
+			// http://stackoverflow.com/a/1068308/13216
+			var m = arg.match(/^--([^=]+)=([\s\S]*)$/);
+			key = m[1];
+			var value = m[2];
+			if (flags.bools[key]) {
+				value = value !== 'false';
+			}
+			setArg(key, value, arg);
+		} else if ((/^--no-.+/).test(arg)) {
+			key = arg.match(/^--no-(.+)/)[1];
+			setArg(key, false, arg);
+		} else if ((/^--.+/).test(arg)) {
+			key = arg.match(/^--(.+)/)[1];
+			next = args[i + 1];
+			if (
+				next !== undefined
+				&& !(/^(-|--)[^-]/).test(next)
+				&& !flags.bools[key]
+				&& !flags.allBools
+				&& (aliases[key] ? !aliasIsBoolean(key) : true)
+			) {
+				setArg(key, next, arg);
+				i += 1;
+			} else if ((/^(true|false)$/).test(next)) {
+				setArg(key, next === 'true', arg);
+				i += 1;
+			} else {
+				setArg(key, flags.strings[key] ? '' : true, arg);
+			}
+		} else if ((/^-[^-]+/).test(arg)) {
+			var letters = arg.slice(1, -1).split('');
+
+			var broken = false;
+			for (var j = 0; j < letters.length; j++) {
+				next = arg.slice(j + 2);
+
+				if (next === '-') {
+					setArg(letters[j], next, arg);
+					continue;
+				}
+
+				if ((/[A-Za-z]/).test(letters[j]) && next[0] === '=') {
+					setArg(letters[j], next.slice(1), arg);
+					broken = true;
+					break;
+				}
+
+				if (
+					(/[A-Za-z]/).test(letters[j])
+					&& (/-?\d+(\.\d*)?(e-?\d+)?$/).test(next)
+				) {
+					setArg(letters[j], next, arg);
+					broken = true;
+					break;
+				}
+
+				if (letters[j + 1] && letters[j + 1].match(/\W/)) {
+					setArg(letters[j], arg.slice(j + 2), arg);
+					broken = true;
+					break;
+				} else {
+					setArg(letters[j], flags.strings[letters[j]] ? '' : true, arg);
+				}
+			}
+
+			key = arg.slice(-1)[0];
+			if (!broken && key !== '-') {
+				if (
+					args[i + 1]
+					&& !(/^(-|--)[^-]/).test(args[i + 1])
+					&& !flags.bools[key]
+					&& (aliases[key] ? !aliasIsBoolean(key) : true)
+				) {
+					setArg(key, args[i + 1], arg);
+					i += 1;
+				} else if (args[i + 1] && (/^(true|false)$/).test(args[i + 1])) {
+					setArg(key, args[i + 1] === 'true', arg);
+					i += 1;
+				} else {
+					setArg(key, flags.strings[key] ? '' : true, arg);
+				}
+			}
+		} else {
+			if (!flags.unknownFn || flags.unknownFn(arg) !== false) {
+				argv._.push(flags.strings._ || !isNumber(arg) ? arg : Number(arg));
+			}
+			if (opts.stopEarly) {
+				argv._.push.apply(argv._, args.slice(i + 1));
+				break;
+			}
+		}
+	}
+
+	Object.keys(defaults).forEach(function (k) {
+		if (!hasKey(argv, k.split('.'))) {
+			setKey(argv, k.split('.'), defaults[k]);
+
+			(aliases[k] || []).forEach(function (x) {
+				setKey(argv, x.split('.'), defaults[k]);
+			});
+		}
+	});
+
+	if (opts['--']) {
+		argv['--'] = notFlags.slice();
+	} else {
+		notFlags.forEach(function (k) {
+			argv._.push(k);
+		});
+	}
+
+	return argv;
+};
diff --git a/server/node_modules/minimist/package.json b/server/node_modules/minimist/package.json
new file mode 100644
index 0000000..c10a334
--- /dev/null
+++ b/server/node_modules/minimist/package.json
@@ -0,0 +1,75 @@
+{
+	"name": "minimist",
+	"version": "1.2.8",
+	"description": "parse argument options",
+	"main": "index.js",
+	"devDependencies": {
+		"@ljharb/eslint-config": "^21.0.1",
+		"aud": "^2.0.2",
+		"auto-changelog": "^2.4.0",
+		"eslint": "=8.8.0",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.0",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.6.3"
+	},
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=auto",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"lint": "eslint --ext=js,mjs .",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "aud --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"testling": {
+		"files": "test/*.js",
+		"browsers": [
+			"ie/6..latest",
+			"ff/5",
+			"firefox/latest",
+			"chrome/10",
+			"chrome/latest",
+			"safari/5.1",
+			"safari/latest",
+			"opera/12"
+		]
+	},
+	"repository": {
+		"type": "git",
+		"url": "git://github.com/minimistjs/minimist.git"
+	},
+	"homepage": "https://github.com/minimistjs/minimist",
+	"keywords": [
+		"argv",
+		"getopt",
+		"parser",
+		"optimist"
+	],
+	"author": {
+		"name": "James Halliday",
+		"email": "mail@substack.net",
+		"url": "http://substack.net"
+	},
+	"funding": {
+		"url": "https://github.com/sponsors/ljharb"
+	},
+	"license": "MIT",
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	}
+}
diff --git a/server/node_modules/minimist/test/all_bool.js b/server/node_modules/minimist/test/all_bool.js
new file mode 100644
index 0000000..befa0c9
--- /dev/null
+++ b/server/node_modules/minimist/test/all_bool.js
@@ -0,0 +1,34 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('flag boolean true (default all --args to boolean)', function (t) {
+	var argv = parse(['moo', '--honk', 'cow'], {
+		boolean: true,
+	});
+
+	t.deepEqual(argv, {
+		honk: true,
+		_: ['moo', 'cow'],
+	});
+
+	t.deepEqual(typeof argv.honk, 'boolean');
+	t.end();
+});
+
+test('flag boolean true only affects double hyphen arguments without equals signs', function (t) {
+	var argv = parse(['moo', '--honk', 'cow', '-p', '55', '--tacos=good'], {
+		boolean: true,
+	});
+
+	t.deepEqual(argv, {
+		honk: true,
+		tacos: 'good',
+		p: 55,
+		_: ['moo', 'cow'],
+	});
+
+	t.deepEqual(typeof argv.honk, 'boolean');
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/bool.js b/server/node_modules/minimist/test/bool.js
new file mode 100644
index 0000000..e58d47e
--- /dev/null
+++ b/server/node_modules/minimist/test/bool.js
@@ -0,0 +1,177 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('flag boolean default false', function (t) {
+	var argv = parse(['moo'], {
+		boolean: ['t', 'verbose'],
+		default: { verbose: false, t: false },
+	});
+
+	t.deepEqual(argv, {
+		verbose: false,
+		t: false,
+		_: ['moo'],
+	});
+
+	t.deepEqual(typeof argv.verbose, 'boolean');
+	t.deepEqual(typeof argv.t, 'boolean');
+	t.end();
+
+});
+
+test('boolean groups', function (t) {
+	var argv = parse(['-x', '-z', 'one', 'two', 'three'], {
+		boolean: ['x', 'y', 'z'],
+	});
+
+	t.deepEqual(argv, {
+		x: true,
+		y: false,
+		z: true,
+		_: ['one', 'two', 'three'],
+	});
+
+	t.deepEqual(typeof argv.x, 'boolean');
+	t.deepEqual(typeof argv.y, 'boolean');
+	t.deepEqual(typeof argv.z, 'boolean');
+	t.end();
+});
+test('boolean and alias with chainable api', function (t) {
+	var aliased = ['-h', 'derp'];
+	var regular = ['--herp', 'derp'];
+	var aliasedArgv = parse(aliased, {
+		boolean: 'herp',
+		alias: { h: 'herp' },
+	});
+	var propertyArgv = parse(regular, {
+		boolean: 'herp',
+		alias: { h: 'herp' },
+	});
+	var expected = {
+		herp: true,
+		h: true,
+		_: ['derp'],
+	};
+
+	t.same(aliasedArgv, expected);
+	t.same(propertyArgv, expected);
+	t.end();
+});
+
+test('boolean and alias with options hash', function (t) {
+	var aliased = ['-h', 'derp'];
+	var regular = ['--herp', 'derp'];
+	var opts = {
+		alias: { h: 'herp' },
+		boolean: 'herp',
+	};
+	var aliasedArgv = parse(aliased, opts);
+	var propertyArgv = parse(regular, opts);
+	var expected = {
+		herp: true,
+		h: true,
+		_: ['derp'],
+	};
+	t.same(aliasedArgv, expected);
+	t.same(propertyArgv, expected);
+	t.end();
+});
+
+test('boolean and alias array with options hash', function (t) {
+	var aliased = ['-h', 'derp'];
+	var regular = ['--herp', 'derp'];
+	var alt = ['--harp', 'derp'];
+	var opts = {
+		alias: { h: ['herp', 'harp'] },
+		boolean: 'h',
+	};
+	var aliasedArgv = parse(aliased, opts);
+	var propertyArgv = parse(regular, opts);
+	var altPropertyArgv = parse(alt, opts);
+	var expected = {
+		harp: true,
+		herp: true,
+		h: true,
+		_: ['derp'],
+	};
+	t.same(aliasedArgv, expected);
+	t.same(propertyArgv, expected);
+	t.same(altPropertyArgv, expected);
+	t.end();
+});
+
+test('boolean and alias using explicit true', function (t) {
+	var aliased = ['-h', 'true'];
+	var regular = ['--herp', 'true'];
+	var opts = {
+		alias: { h: 'herp' },
+		boolean: 'h',
+	};
+	var aliasedArgv = parse(aliased, opts);
+	var propertyArgv = parse(regular, opts);
+	var expected = {
+		herp: true,
+		h: true,
+		_: [],
+	};
+
+	t.same(aliasedArgv, expected);
+	t.same(propertyArgv, expected);
+	t.end();
+});
+
+// regression, see https://github.com/substack/node-optimist/issues/71
+test('boolean and --x=true', function (t) {
+	var parsed = parse(['--boool', '--other=true'], {
+		boolean: 'boool',
+	});
+
+	t.same(parsed.boool, true);
+	t.same(parsed.other, 'true');
+
+	parsed = parse(['--boool', '--other=false'], {
+		boolean: 'boool',
+	});
+
+	t.same(parsed.boool, true);
+	t.same(parsed.other, 'false');
+	t.end();
+});
+
+test('boolean --boool=true', function (t) {
+	var parsed = parse(['--boool=true'], {
+		default: {
+			boool: false,
+		},
+		boolean: ['boool'],
+	});
+
+	t.same(parsed.boool, true);
+	t.end();
+});
+
+test('boolean --boool=false', function (t) {
+	var parsed = parse(['--boool=false'], {
+		default: {
+			boool: true,
+		},
+		boolean: ['boool'],
+	});
+
+	t.same(parsed.boool, false);
+	t.end();
+});
+
+test('boolean using something similar to true', function (t) {
+	var opts = { boolean: 'h' };
+	var result = parse(['-h', 'true.txt'], opts);
+	var expected = {
+		h: true,
+		_: ['true.txt'],
+	};
+
+	t.same(result, expected);
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/dash.js b/server/node_modules/minimist/test/dash.js
new file mode 100644
index 0000000..7078817
--- /dev/null
+++ b/server/node_modules/minimist/test/dash.js
@@ -0,0 +1,43 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('-', function (t) {
+	t.plan(6);
+	t.deepEqual(parse(['-n', '-']), { n: '-', _: [] });
+	t.deepEqual(parse(['--nnn', '-']), { nnn: '-', _: [] });
+	t.deepEqual(parse(['-']), { _: ['-'] });
+	t.deepEqual(parse(['-f-']), { f: '-', _: [] });
+	t.deepEqual(
+		parse(['-b', '-'], { boolean: 'b' }),
+		{ b: true, _: ['-'] }
+	);
+	t.deepEqual(
+		parse(['-s', '-'], { string: 's' }),
+		{ s: '-', _: [] }
+	);
+});
+
+test('-a -- b', function (t) {
+	t.plan(2);
+	t.deepEqual(parse(['-a', '--', 'b']), { a: true, _: ['b'] });
+	t.deepEqual(parse(['--a', '--', 'b']), { a: true, _: ['b'] });
+});
+
+test('move arguments after the -- into their own `--` array', function (t) {
+	t.plan(1);
+	t.deepEqual(
+		parse(['--name', 'John', 'before', '--', 'after'], { '--': true }),
+		{ name: 'John', _: ['before'], '--': ['after'] }
+	);
+});
+
+test('--- option value', function (t) {
+	// A multi-dash value is largely an edge case, but check the behaviour is as expected,
+	// and in particular the same for short option and long option (as made consistent in Jan 2023).
+	t.plan(2);
+	t.deepEqual(parse(['-n', '---']), { n: '---', _: [] });
+	t.deepEqual(parse(['--nnn', '---']), { nnn: '---', _: [] });
+});
+
diff --git a/server/node_modules/minimist/test/default_bool.js b/server/node_modules/minimist/test/default_bool.js
new file mode 100644
index 0000000..4e9f625
--- /dev/null
+++ b/server/node_modules/minimist/test/default_bool.js
@@ -0,0 +1,37 @@
+'use strict';
+
+var test = require('tape');
+var parse = require('../');
+
+test('boolean default true', function (t) {
+	var argv = parse([], {
+		boolean: 'sometrue',
+		default: { sometrue: true },
+	});
+	t.equal(argv.sometrue, true);
+	t.end();
+});
+
+test('boolean default false', function (t) {
+	var argv = parse([], {
+		boolean: 'somefalse',
+		default: { somefalse: false },
+	});
+	t.equal(argv.somefalse, false);
+	t.end();
+});
+
+test('boolean default to null', function (t) {
+	var argv = parse([], {
+		boolean: 'maybe',
+		default: { maybe: null },
+	});
+	t.equal(argv.maybe, null);
+
+	var argvLong = parse(['--maybe'], {
+		boolean: 'maybe',
+		default: { maybe: null },
+	});
+	t.equal(argvLong.maybe, true);
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/dotted.js b/server/node_modules/minimist/test/dotted.js
new file mode 100644
index 0000000..126ff03
--- /dev/null
+++ b/server/node_modules/minimist/test/dotted.js
@@ -0,0 +1,24 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('dotted alias', function (t) {
+	var argv = parse(['--a.b', '22'], { default: { 'a.b': 11 }, alias: { 'a.b': 'aa.bb' } });
+	t.equal(argv.a.b, 22);
+	t.equal(argv.aa.bb, 22);
+	t.end();
+});
+
+test('dotted default', function (t) {
+	var argv = parse('', { default: { 'a.b': 11 }, alias: { 'a.b': 'aa.bb' } });
+	t.equal(argv.a.b, 11);
+	t.equal(argv.aa.bb, 11);
+	t.end();
+});
+
+test('dotted default with no alias', function (t) {
+	var argv = parse('', { default: { 'a.b': 11 } });
+	t.equal(argv.a.b, 11);
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/kv_short.js b/server/node_modules/minimist/test/kv_short.js
new file mode 100644
index 0000000..6d1b53a
--- /dev/null
+++ b/server/node_modules/minimist/test/kv_short.js
@@ -0,0 +1,32 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('short -k=v', function (t) {
+	t.plan(1);
+
+	var argv = parse(['-b=123']);
+	t.deepEqual(argv, { b: 123, _: [] });
+});
+
+test('multi short -k=v', function (t) {
+	t.plan(1);
+
+	var argv = parse(['-a=whatever', '-b=robots']);
+	t.deepEqual(argv, { a: 'whatever', b: 'robots', _: [] });
+});
+
+test('short with embedded equals -k=a=b', function (t) {
+	t.plan(1);
+
+	var argv = parse(['-k=a=b']);
+	t.deepEqual(argv, { k: 'a=b', _: [] });
+});
+
+test('short with later equals like -ab=c', function (t) {
+	t.plan(1);
+
+	var argv = parse(['-ab=c']);
+	t.deepEqual(argv, { a: true, b: 'c', _: [] });
+});
diff --git a/server/node_modules/minimist/test/long.js b/server/node_modules/minimist/test/long.js
new file mode 100644
index 0000000..9fef51f
--- /dev/null
+++ b/server/node_modules/minimist/test/long.js
@@ -0,0 +1,33 @@
+'use strict';
+
+var test = require('tape');
+var parse = require('../');
+
+test('long opts', function (t) {
+	t.deepEqual(
+		parse(['--bool']),
+		{ bool: true, _: [] },
+		'long boolean'
+	);
+	t.deepEqual(
+		parse(['--pow', 'xixxle']),
+		{ pow: 'xixxle', _: [] },
+		'long capture sp'
+	);
+	t.deepEqual(
+		parse(['--pow=xixxle']),
+		{ pow: 'xixxle', _: [] },
+		'long capture eq'
+	);
+	t.deepEqual(
+		parse(['--host', 'localhost', '--port', '555']),
+		{ host: 'localhost', port: 555, _: [] },
+		'long captures sp'
+	);
+	t.deepEqual(
+		parse(['--host=localhost', '--port=555']),
+		{ host: 'localhost', port: 555, _: [] },
+		'long captures eq'
+	);
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/num.js b/server/node_modules/minimist/test/num.js
new file mode 100644
index 0000000..074393e
--- /dev/null
+++ b/server/node_modules/minimist/test/num.js
@@ -0,0 +1,38 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('nums', function (t) {
+	var argv = parse([
+		'-x', '1234',
+		'-y', '5.67',
+		'-z', '1e7',
+		'-w', '10f',
+		'--hex', '0xdeadbeef',
+		'789',
+	]);
+	t.deepEqual(argv, {
+		x: 1234,
+		y: 5.67,
+		z: 1e7,
+		w: '10f',
+		hex: 0xdeadbeef,
+		_: [789],
+	});
+	t.deepEqual(typeof argv.x, 'number');
+	t.deepEqual(typeof argv.y, 'number');
+	t.deepEqual(typeof argv.z, 'number');
+	t.deepEqual(typeof argv.w, 'string');
+	t.deepEqual(typeof argv.hex, 'number');
+	t.deepEqual(typeof argv._[0], 'number');
+	t.end();
+});
+
+test('already a number', function (t) {
+	var argv = parse(['-x', 1234, 789]);
+	t.deepEqual(argv, { x: 1234, _: [789] });
+	t.deepEqual(typeof argv.x, 'number');
+	t.deepEqual(typeof argv._[0], 'number');
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/parse.js b/server/node_modules/minimist/test/parse.js
new file mode 100644
index 0000000..65d9d90
--- /dev/null
+++ b/server/node_modules/minimist/test/parse.js
@@ -0,0 +1,209 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('parse args', function (t) {
+	t.deepEqual(
+		parse(['--no-moo']),
+		{ moo: false, _: [] },
+		'no'
+	);
+	t.deepEqual(
+		parse(['-v', 'a', '-v', 'b', '-v', 'c']),
+		{ v: ['a', 'b', 'c'], _: [] },
+		'multi'
+	);
+	t.end();
+});
+
+test('comprehensive', function (t) {
+	t.deepEqual(
+		parse([
+			'--name=meowmers', 'bare', '-cats', 'woo',
+			'-h', 'awesome', '--multi=quux',
+			'--key', 'value',
+			'-b', '--bool', '--no-meep', '--multi=baz',
+			'--', '--not-a-flag', 'eek',
+		]),
+		{
+			c: true,
+			a: true,
+			t: true,
+			s: 'woo',
+			h: 'awesome',
+			b: true,
+			bool: true,
+			key: 'value',
+			multi: ['quux', 'baz'],
+			meep: false,
+			name: 'meowmers',
+			_: ['bare', '--not-a-flag', 'eek'],
+		}
+	);
+	t.end();
+});
+
+test('flag boolean', function (t) {
+	var argv = parse(['-t', 'moo'], { boolean: 't' });
+	t.deepEqual(argv, { t: true, _: ['moo'] });
+	t.deepEqual(typeof argv.t, 'boolean');
+	t.end();
+});
+
+test('flag boolean value', function (t) {
+	var argv = parse(['--verbose', 'false', 'moo', '-t', 'true'], {
+		boolean: ['t', 'verbose'],
+		default: { verbose: true },
+	});
+
+	t.deepEqual(argv, {
+		verbose: false,
+		t: true,
+		_: ['moo'],
+	});
+
+	t.deepEqual(typeof argv.verbose, 'boolean');
+	t.deepEqual(typeof argv.t, 'boolean');
+	t.end();
+});
+
+test('newlines in params', function (t) {
+	var args = parse(['-s', 'X\nX']);
+	t.deepEqual(args, { _: [], s: 'X\nX' });
+
+	// reproduce in bash:
+	// VALUE="new
+	// line"
+	// node program.js --s="$VALUE"
+	args = parse(['--s=X\nX']);
+	t.deepEqual(args, { _: [], s: 'X\nX' });
+	t.end();
+});
+
+test('strings', function (t) {
+	var s = parse(['-s', '0001234'], { string: 's' }).s;
+	t.equal(s, '0001234');
+	t.equal(typeof s, 'string');
+
+	var x = parse(['-x', '56'], { string: 'x' }).x;
+	t.equal(x, '56');
+	t.equal(typeof x, 'string');
+	t.end();
+});
+
+test('stringArgs', function (t) {
+	var s = parse(['  ', '  '], { string: '_' })._;
+	t.same(s.length, 2);
+	t.same(typeof s[0], 'string');
+	t.same(s[0], '  ');
+	t.same(typeof s[1], 'string');
+	t.same(s[1], '  ');
+	t.end();
+});
+
+test('empty strings', function (t) {
+	var s = parse(['-s'], { string: 's' }).s;
+	t.equal(s, '');
+	t.equal(typeof s, 'string');
+
+	var str = parse(['--str'], { string: 'str' }).str;
+	t.equal(str, '');
+	t.equal(typeof str, 'string');
+
+	var letters = parse(['-art'], {
+		string: ['a', 't'],
+	});
+
+	t.equal(letters.a, '');
+	t.equal(letters.r, true);
+	t.equal(letters.t, '');
+
+	t.end();
+});
+
+test('string and alias', function (t) {
+	var x = parse(['--str', '000123'], {
+		string: 's',
+		alias: { s: 'str' },
+	});
+
+	t.equal(x.str, '000123');
+	t.equal(typeof x.str, 'string');
+	t.equal(x.s, '000123');
+	t.equal(typeof x.s, 'string');
+
+	var y = parse(['-s', '000123'], {
+		string: 'str',
+		alias: { str: 's' },
+	});
+
+	t.equal(y.str, '000123');
+	t.equal(typeof y.str, 'string');
+	t.equal(y.s, '000123');
+	t.equal(typeof y.s, 'string');
+
+	var z = parse(['-s123'], {
+		alias: { str: ['s', 'S'] },
+		string: ['str'],
+	});
+
+	t.deepEqual(
+		z,
+		{ _: [], s: '123', S: '123', str: '123' },
+		'opt.string works with multiple aliases'
+	);
+	t.end();
+});
+
+test('slashBreak', function (t) {
+	t.same(
+		parse(['-I/foo/bar/baz']),
+		{ I: '/foo/bar/baz', _: [] }
+	);
+	t.same(
+		parse(['-xyz/foo/bar/baz']),
+		{ x: true, y: true, z: '/foo/bar/baz', _: [] }
+	);
+	t.end();
+});
+
+test('alias', function (t) {
+	var argv = parse(['-f', '11', '--zoom', '55'], {
+		alias: { z: 'zoom' },
+	});
+	t.equal(argv.zoom, 55);
+	t.equal(argv.z, argv.zoom);
+	t.equal(argv.f, 11);
+	t.end();
+});
+
+test('multiAlias', function (t) {
+	var argv = parse(['-f', '11', '--zoom', '55'], {
+		alias: { z: ['zm', 'zoom'] },
+	});
+	t.equal(argv.zoom, 55);
+	t.equal(argv.z, argv.zoom);
+	t.equal(argv.z, argv.zm);
+	t.equal(argv.f, 11);
+	t.end();
+});
+
+test('nested dotted objects', function (t) {
+	var argv = parse([
+		'--foo.bar', '3', '--foo.baz', '4',
+		'--foo.quux.quibble', '5', '--foo.quux.o_O',
+		'--beep.boop',
+	]);
+
+	t.same(argv.foo, {
+		bar: 3,
+		baz: 4,
+		quux: {
+			quibble: 5,
+			o_O: true,
+		},
+	});
+	t.same(argv.beep, { boop: true });
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/parse_modified.js b/server/node_modules/minimist/test/parse_modified.js
new file mode 100644
index 0000000..32965d1
--- /dev/null
+++ b/server/node_modules/minimist/test/parse_modified.js
@@ -0,0 +1,11 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('parse with modifier functions', function (t) {
+	t.plan(1);
+
+	var argv = parse(['-b', '123'], { boolean: 'b' });
+	t.deepEqual(argv, { b: true, _: [123] });
+});
diff --git a/server/node_modules/minimist/test/proto.js b/server/node_modules/minimist/test/proto.js
new file mode 100644
index 0000000..6e629dd
--- /dev/null
+++ b/server/node_modules/minimist/test/proto.js
@@ -0,0 +1,64 @@
+'use strict';
+
+/* eslint no-proto: 0 */
+
+var parse = require('../');
+var test = require('tape');
+
+test('proto pollution', function (t) {
+	var argv = parse(['--__proto__.x', '123']);
+	t.equal({}.x, undefined);
+	t.equal(argv.__proto__.x, undefined);
+	t.equal(argv.x, undefined);
+	t.end();
+});
+
+test('proto pollution (array)', function (t) {
+	var argv = parse(['--x', '4', '--x', '5', '--x.__proto__.z', '789']);
+	t.equal({}.z, undefined);
+	t.deepEqual(argv.x, [4, 5]);
+	t.equal(argv.x.z, undefined);
+	t.equal(argv.x.__proto__.z, undefined);
+	t.end();
+});
+
+test('proto pollution (number)', function (t) {
+	var argv = parse(['--x', '5', '--x.__proto__.z', '100']);
+	t.equal({}.z, undefined);
+	t.equal((4).z, undefined);
+	t.equal(argv.x, 5);
+	t.equal(argv.x.z, undefined);
+	t.end();
+});
+
+test('proto pollution (string)', function (t) {
+	var argv = parse(['--x', 'abc', '--x.__proto__.z', 'def']);
+	t.equal({}.z, undefined);
+	t.equal('...'.z, undefined);
+	t.equal(argv.x, 'abc');
+	t.equal(argv.x.z, undefined);
+	t.end();
+});
+
+test('proto pollution (constructor)', function (t) {
+	var argv = parse(['--constructor.prototype.y', '123']);
+	t.equal({}.y, undefined);
+	t.equal(argv.y, undefined);
+	t.end();
+});
+
+test('proto pollution (constructor function)', function (t) {
+	var argv = parse(['--_.concat.constructor.prototype.y', '123']);
+	function fnToBeTested() {}
+	t.equal(fnToBeTested.y, undefined);
+	t.equal(argv.y, undefined);
+	t.end();
+});
+
+// powered by snyk - https://github.com/backstage/backstage/issues/10343
+test('proto pollution (constructor function) snyk', function (t) {
+	var argv = parse('--_.constructor.constructor.prototype.foo bar'.split(' '));
+	t.equal(function () {}.foo, undefined);
+	t.equal(argv.y, undefined);
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/short.js b/server/node_modules/minimist/test/short.js
new file mode 100644
index 0000000..4a7b843
--- /dev/null
+++ b/server/node_modules/minimist/test/short.js
@@ -0,0 +1,69 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('numeric short args', function (t) {
+	t.plan(2);
+	t.deepEqual(parse(['-n123']), { n: 123, _: [] });
+	t.deepEqual(
+		parse(['-123', '456']),
+		{ 1: true, 2: true, 3: 456, _: [] }
+	);
+});
+
+test('short', function (t) {
+	t.deepEqual(
+		parse(['-b']),
+		{ b: true, _: [] },
+		'short boolean'
+	);
+	t.deepEqual(
+		parse(['foo', 'bar', 'baz']),
+		{ _: ['foo', 'bar', 'baz'] },
+		'bare'
+	);
+	t.deepEqual(
+		parse(['-cats']),
+		{ c: true, a: true, t: true, s: true, _: [] },
+		'group'
+	);
+	t.deepEqual(
+		parse(['-cats', 'meow']),
+		{ c: true, a: true, t: true, s: 'meow', _: [] },
+		'short group next'
+	);
+	t.deepEqual(
+		parse(['-h', 'localhost']),
+		{ h: 'localhost', _: [] },
+		'short capture'
+	);
+	t.deepEqual(
+		parse(['-h', 'localhost', '-p', '555']),
+		{ h: 'localhost', p: 555, _: [] },
+		'short captures'
+	);
+	t.end();
+});
+
+test('mixed short bool and capture', function (t) {
+	t.same(
+		parse(['-h', 'localhost', '-fp', '555', 'script.js']),
+		{
+			f: true, p: 555, h: 'localhost',
+			_: ['script.js'],
+		}
+	);
+	t.end();
+});
+
+test('short and long', function (t) {
+	t.deepEqual(
+		parse(['-h', 'localhost', '-fp', '555', 'script.js']),
+		{
+			f: true, p: 555, h: 'localhost',
+			_: ['script.js'],
+		}
+	);
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/stop_early.js b/server/node_modules/minimist/test/stop_early.js
new file mode 100644
index 0000000..52a6a91
--- /dev/null
+++ b/server/node_modules/minimist/test/stop_early.js
@@ -0,0 +1,17 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('stops parsing on the first non-option when stopEarly is set', function (t) {
+	var argv = parse(['--aaa', 'bbb', 'ccc', '--ddd'], {
+		stopEarly: true,
+	});
+
+	t.deepEqual(argv, {
+		aaa: 'bbb',
+		_: ['ccc', '--ddd'],
+	});
+
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/unknown.js b/server/node_modules/minimist/test/unknown.js
new file mode 100644
index 0000000..4f2e0ca
--- /dev/null
+++ b/server/node_modules/minimist/test/unknown.js
@@ -0,0 +1,104 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('boolean and alias is not unknown', function (t) {
+	var unknown = [];
+	function unknownFn(arg) {
+		unknown.push(arg);
+		return false;
+	}
+	var aliased = ['-h', 'true', '--derp', 'true'];
+	var regular = ['--herp', 'true', '-d', 'true'];
+	var opts = {
+		alias: { h: 'herp' },
+		boolean: 'h',
+		unknown: unknownFn,
+	};
+	parse(aliased, opts);
+	parse(regular, opts);
+
+	t.same(unknown, ['--derp', '-d']);
+	t.end();
+});
+
+test('flag boolean true any double hyphen argument is not unknown', function (t) {
+	var unknown = [];
+	function unknownFn(arg) {
+		unknown.push(arg);
+		return false;
+	}
+	var argv = parse(['--honk', '--tacos=good', 'cow', '-p', '55'], {
+		boolean: true,
+		unknown: unknownFn,
+	});
+	t.same(unknown, ['--tacos=good', 'cow', '-p']);
+	t.same(argv, {
+		honk: true,
+		_: [],
+	});
+	t.end();
+});
+
+test('string and alias is not unknown', function (t) {
+	var unknown = [];
+	function unknownFn(arg) {
+		unknown.push(arg);
+		return false;
+	}
+	var aliased = ['-h', 'hello', '--derp', 'goodbye'];
+	var regular = ['--herp', 'hello', '-d', 'moon'];
+	var opts = {
+		alias: { h: 'herp' },
+		string: 'h',
+		unknown: unknownFn,
+	};
+	parse(aliased, opts);
+	parse(regular, opts);
+
+	t.same(unknown, ['--derp', '-d']);
+	t.end();
+});
+
+test('default and alias is not unknown', function (t) {
+	var unknown = [];
+	function unknownFn(arg) {
+		unknown.push(arg);
+		return false;
+	}
+	var aliased = ['-h', 'hello'];
+	var regular = ['--herp', 'hello'];
+	var opts = {
+		default: { h: 'bar' },
+		alias: { h: 'herp' },
+		unknown: unknownFn,
+	};
+	parse(aliased, opts);
+	parse(regular, opts);
+
+	t.same(unknown, []);
+	t.end();
+	unknownFn(); // exercise fn for 100% coverage
+});
+
+test('value following -- is not unknown', function (t) {
+	var unknown = [];
+	function unknownFn(arg) {
+		unknown.push(arg);
+		return false;
+	}
+	var aliased = ['--bad', '--', 'good', 'arg'];
+	var opts = {
+		'--': true,
+		unknown: unknownFn,
+	};
+	var argv = parse(aliased, opts);
+
+	t.same(unknown, ['--bad']);
+	t.same(argv, {
+		'--': ['good', 'arg'],
+		_: [],
+	});
+	t.end();
+});
diff --git a/server/node_modules/minimist/test/whitespace.js b/server/node_modules/minimist/test/whitespace.js
new file mode 100644
index 0000000..4fdaf1d
--- /dev/null
+++ b/server/node_modules/minimist/test/whitespace.js
@@ -0,0 +1,10 @@
+'use strict';
+
+var parse = require('../');
+var test = require('tape');
+
+test('whitespace should be whitespace', function (t) {
+	t.plan(1);
+	var x = parse(['-x', '\t']).x;
+	t.equal(x, '\t');
+});
diff --git a/server/node_modules/minipass-collect/LICENSE b/server/node_modules/minipass-collect/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/minipass-collect/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/minipass-collect/README.md b/server/node_modules/minipass-collect/README.md
new file mode 100644
index 0000000..ae1c3da
--- /dev/null
+++ b/server/node_modules/minipass-collect/README.md
@@ -0,0 +1,48 @@
+# minipass-collect
+
+A Minipass stream that collects all the data into a single chunk
+
+Note that this buffers ALL data written to it, so it's only good for
+situations where you are sure the entire stream fits in memory.
+
+Note: this is primarily useful for the `Collect.PassThrough` class, since
+Minipass streams already have a `.collect()` method which returns a promise
+that resolves to the array of chunks, and a `.concat()` method that returns
+the data concatenated into a single Buffer or String.
+
+## USAGE
+
+```js
+const Collect = require('minipass-collect')
+
+const collector = new Collect()
+collector.on('data', allTheData => {
+  console.log('all the data!', allTheData)
+})
+
+someSourceOfData.pipe(collector)
+
+// note that you can also simply do:
+someSourceOfData.pipe(new Minipass()).concat().then(data => ...)
+// or even, if someSourceOfData is a Minipass:
+someSourceOfData.concat().then(data => ...)
+// but you might prefer to have it stream-shaped rather than
+// Promise-shaped in some scenarios.
+```
+
+If you want to collect the data, but _also_ act as a passthrough stream,
+then use `Collect.PassThrough` instead (for example to memoize streaming
+responses), and listen on the `collect` event.
+
+```js
+const Collect = require('minipass-collect')
+
+const collector = new Collect.PassThrough()
+collector.on('collect', allTheData => {
+  console.log('all the data!', allTheData)
+})
+
+someSourceOfData.pipe(collector).pipe(someOtherStream)
+```
+
+All [minipass options](http://npm.im/minipass) are supported.
diff --git a/server/node_modules/minipass-collect/index.js b/server/node_modules/minipass-collect/index.js
new file mode 100644
index 0000000..2fe68c0
--- /dev/null
+++ b/server/node_modules/minipass-collect/index.js
@@ -0,0 +1,71 @@
+const Minipass = require('minipass')
+const _data = Symbol('_data')
+const _length = Symbol('_length')
+class Collect extends Minipass {
+  constructor (options) {
+    super(options)
+    this[_data] = []
+    this[_length] = 0
+  }
+  write (chunk, encoding, cb) {
+    if (typeof encoding === 'function')
+      cb = encoding, encoding = 'utf8'
+
+    if (!encoding)
+      encoding = 'utf8'
+
+    const c = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk, encoding)
+    this[_data].push(c)
+    this[_length] += c.length
+    if (cb)
+      cb()
+    return true
+  }
+  end (chunk, encoding, cb) {
+    if (typeof chunk === 'function')
+      cb = chunk, chunk = null
+    if (typeof encoding === 'function')
+      cb = encoding, encoding = 'utf8'
+    if (chunk)
+      this.write(chunk, encoding)
+    const result = Buffer.concat(this[_data], this[_length])
+    super.write(result)
+    return super.end(cb)
+  }
+}
+module.exports = Collect
+
+// it would be possible to DRY this a bit by doing something like
+// this.collector = new Collect() and listening on its data event,
+// but it's not much code, and we may as well save the extra obj
+class CollectPassThrough extends Minipass {
+  constructor (options) {
+    super(options)
+    this[_data] = []
+    this[_length] = 0
+  }
+  write (chunk, encoding, cb) {
+    if (typeof encoding === 'function')
+      cb = encoding, encoding = 'utf8'
+
+    if (!encoding)
+      encoding = 'utf8'
+
+    const c = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk, encoding)
+    this[_data].push(c)
+    this[_length] += c.length
+    return super.write(chunk, encoding, cb)
+  }
+  end (chunk, encoding, cb) {
+    if (typeof chunk === 'function')
+      cb = chunk, chunk = null
+    if (typeof encoding === 'function')
+      cb = encoding, encoding = 'utf8'
+    if (chunk)
+      this.write(chunk, encoding)
+    const result = Buffer.concat(this[_data], this[_length])
+    this.emit('collect', result)
+    return super.end(cb)
+  }
+}
+module.exports.PassThrough = CollectPassThrough
diff --git a/server/node_modules/minipass-collect/package.json b/server/node_modules/minipass-collect/package.json
new file mode 100644
index 0000000..54d87ac
--- /dev/null
+++ b/server/node_modules/minipass-collect/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "minipass-collect",
+  "version": "1.0.2",
+  "description": "A Minipass stream that collects all the data into a single chunk",
+  "author": "Isaac Z. Schlueter <i@izs.me> (https://izs.me)",
+  "license": "ISC",
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "tap": {
+    "check-coverage": true
+  },
+  "devDependencies": {
+    "tap": "^14.6.9"
+  },
+  "dependencies": {
+    "minipass": "^3.0.0"
+  },
+  "files": [
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 8"
+  }
+}
diff --git a/server/node_modules/minipass-fetch/LICENSE b/server/node_modules/minipass-fetch/LICENSE
new file mode 100644
index 0000000..3c3410c
--- /dev/null
+++ b/server/node_modules/minipass-fetch/LICENSE
@@ -0,0 +1,28 @@
+The MIT License (MIT)
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+Copyright (c) 2016 David Frank
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+---
+
+Note: This is a derivative work based on "node-fetch" by David Frank,
+modified and distributed under the terms of the MIT license above.
+https://github.com/bitinn/node-fetch
diff --git a/server/node_modules/minipass-fetch/README.md b/server/node_modules/minipass-fetch/README.md
new file mode 100644
index 0000000..925e6be
--- /dev/null
+++ b/server/node_modules/minipass-fetch/README.md
@@ -0,0 +1,29 @@
+# minipass-fetch
+
+An implementation of window.fetch in Node.js using Minipass streams
+
+This is a fork (or more precisely, a reimplementation) of
+[node-fetch](http://npm.im/node-fetch).  All streams have been replaced
+with [minipass streams](http://npm.im/minipass).
+
+The goal of this module is to stay in sync with the API presented by
+`node-fetch`, with the exception of the streaming interface provided.
+
+## Why
+
+Minipass streams are faster and more deterministic in their timing contract
+than node-core streams, making them a better fit for many server-side use
+cases.
+
+## API
+
+See [node-fetch](http://npm.im/node-fetch)
+
+Differences from `node-fetch` (and, by extension, from the WhatWG Fetch
+specification):
+
+- Returns [minipass](http://npm.im/minipass) streams instead of node-core
+  streams.
+- Supports the full set of [TLS Options that may be provided to
+  `https.request()`](https://nodejs.org/api/https.html#https_https_request_options_callback)
+  when making `https` requests.
diff --git a/server/node_modules/minipass-fetch/index.js b/server/node_modules/minipass-fetch/index.js
new file mode 100644
index 0000000..07efc17
--- /dev/null
+++ b/server/node_modules/minipass-fetch/index.js
@@ -0,0 +1 @@
+module.exports = require('./lib/index.js')
diff --git a/server/node_modules/minipass-fetch/lib/abort-error.js b/server/node_modules/minipass-fetch/lib/abort-error.js
new file mode 100644
index 0000000..b18f643
--- /dev/null
+++ b/server/node_modules/minipass-fetch/lib/abort-error.js
@@ -0,0 +1,17 @@
+'use strict'
+class AbortError extends Error {
+  constructor (message) {
+    super(message)
+    this.code = 'FETCH_ABORTED'
+    this.type = 'aborted'
+    Error.captureStackTrace(this, this.constructor)
+  }
+
+  get name () {
+    return 'AbortError'
+  }
+
+  // don't allow name to be overridden, but don't throw either
+  set name (s) {}
+}
+module.exports = AbortError
diff --git a/server/node_modules/minipass-fetch/lib/blob.js b/server/node_modules/minipass-fetch/lib/blob.js
new file mode 100644
index 0000000..9225db6
--- /dev/null
+++ b/server/node_modules/minipass-fetch/lib/blob.js
@@ -0,0 +1,97 @@
+'use strict'
+const Minipass = require('minipass')
+const TYPE = Symbol('type')
+const BUFFER = Symbol('buffer')
+
+class Blob {
+  constructor (blobParts, options) {
+    this[TYPE] = ''
+
+    const buffers = []
+    let size = 0
+
+    if (blobParts) {
+      const a = blobParts
+      const length = Number(a.length)
+      for (let i = 0; i < length; i++) {
+        const element = a[i]
+        const buffer = element instanceof Buffer ? element
+          : ArrayBuffer.isView(element)
+            ? Buffer.from(element.buffer, element.byteOffset, element.byteLength)
+          : element instanceof ArrayBuffer ? Buffer.from(element)
+          : element instanceof Blob ? element[BUFFER]
+          : typeof element === 'string' ? Buffer.from(element)
+          : Buffer.from(String(element))
+        size += buffer.length
+        buffers.push(buffer)
+      }
+    }
+
+    this[BUFFER] = Buffer.concat(buffers, size)
+
+    const type = options && options.type !== undefined
+      && String(options.type).toLowerCase()
+    if (type && !/[^\u0020-\u007E]/.test(type)) {
+      this[TYPE] = type
+    }
+  }
+
+  get size () {
+    return this[BUFFER].length
+  }
+
+  get type () {
+    return this[TYPE]
+  }
+
+  text () {
+    return Promise.resolve(this[BUFFER].toString())
+  }
+
+  arrayBuffer () {
+    const buf = this[BUFFER]
+    const off = buf.byteOffset
+    const len = buf.byteLength
+    const ab = buf.buffer.slice(off, off + len)
+    return Promise.resolve(ab)
+  }
+
+  stream () {
+    return new Minipass().end(this[BUFFER])
+  }
+
+  slice (start, end, type) {
+    const size = this.size
+    const relativeStart = start === undefined ? 0
+      : start < 0 ? Math.max(size + start, 0)
+      : Math.min(start, size)
+    const relativeEnd = end === undefined ? size
+      : end < 0 ? Math.max(size + end, 0)
+      : Math.min(end, size)
+    const span = Math.max(relativeEnd - relativeStart, 0)
+
+    const buffer = this[BUFFER]
+    const slicedBuffer = buffer.slice(
+      relativeStart,
+      relativeStart + span
+    )
+    const blob = new Blob([], { type })
+    blob[BUFFER] = slicedBuffer
+    return blob
+  }
+
+  get [Symbol.toStringTag] () {
+    return 'Blob'
+  }
+
+  static get BUFFER () {
+    return BUFFER
+  }
+}
+
+Object.defineProperties(Blob.prototype, {
+  size: { enumerable: true },
+  type: { enumerable: true },
+})
+
+module.exports = Blob
diff --git a/server/node_modules/minipass-fetch/lib/body.js b/server/node_modules/minipass-fetch/lib/body.js
new file mode 100644
index 0000000..fb7ffc3
--- /dev/null
+++ b/server/node_modules/minipass-fetch/lib/body.js
@@ -0,0 +1,334 @@
+'use strict'
+const Minipass = require('minipass')
+const MinipassSized = require('minipass-sized')
+
+const Blob = require('./blob.js')
+const {BUFFER} = Blob
+const FetchError = require('./fetch-error.js')
+
+// optional dependency on 'encoding'
+let convert
+try {
+  convert = require('encoding').convert
+} catch (e) {}
+
+const INTERNALS = Symbol('Body internals')
+const CONSUME_BODY = Symbol('consumeBody')
+
+class Body {
+  constructor (bodyArg, options = {}) {
+    const { size = 0, timeout = 0 } = options
+    const body = bodyArg === undefined || bodyArg === null ? null
+      : isURLSearchParams(bodyArg) ? Buffer.from(bodyArg.toString())
+      : isBlob(bodyArg) ? bodyArg
+      : Buffer.isBuffer(bodyArg) ? bodyArg
+      : Object.prototype.toString.call(bodyArg) === '[object ArrayBuffer]'
+        ? Buffer.from(bodyArg)
+      : ArrayBuffer.isView(bodyArg)
+        ? Buffer.from(bodyArg.buffer, bodyArg.byteOffset, bodyArg.byteLength)
+      : Minipass.isStream(bodyArg) ? bodyArg
+      : Buffer.from(String(bodyArg))
+
+    this[INTERNALS] = {
+      body,
+      disturbed: false,
+      error: null,
+    }
+
+    this.size = size
+    this.timeout = timeout
+
+    if (Minipass.isStream(body)) {
+      body.on('error', er => {
+        const error = er.name === 'AbortError' ? er
+          : new FetchError(`Invalid response while trying to fetch ${
+            this.url}: ${er.message}`, 'system', er)
+        this[INTERNALS].error = error
+      })
+    }
+  }
+
+  get body () {
+    return this[INTERNALS].body
+  }
+
+  get bodyUsed () {
+    return this[INTERNALS].disturbed
+  }
+
+  arrayBuffer () {
+    return this[CONSUME_BODY]().then(buf =>
+      buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength))
+  }
+
+  blob () {
+    const ct = this.headers && this.headers.get('content-type') || ''
+    return this[CONSUME_BODY]().then(buf => Object.assign(
+      new Blob([], { type: ct.toLowerCase() }),
+      { [BUFFER]: buf }
+    ))
+  }
+
+  json () {
+    return this[CONSUME_BODY]().then(buf => {
+      try {
+        return JSON.parse(buf.toString())
+      } catch (er) {
+        return Promise.reject(new FetchError(
+          `invalid json response body at ${
+            this.url} reason: ${er.message}`, 'invalid-json'))
+      }
+    })
+  }
+
+  text () {
+    return this[CONSUME_BODY]().then(buf => buf.toString())
+  }
+
+  buffer () {
+    return this[CONSUME_BODY]()
+  }
+
+  textConverted () {
+    return this[CONSUME_BODY]().then(buf => convertBody(buf, this.headers))
+  }
+
+  [CONSUME_BODY] () {
+    if (this[INTERNALS].disturbed)
+      return Promise.reject(new TypeError(`body used already for: ${
+        this.url}`))
+
+    this[INTERNALS].disturbed = true
+
+    if (this[INTERNALS].error)
+      return Promise.reject(this[INTERNALS].error)
+
+    // body is null
+    if (this.body === null) {
+      return Promise.resolve(Buffer.alloc(0))
+    }
+
+    if (Buffer.isBuffer(this.body))
+      return Promise.resolve(this.body)
+
+    const upstream = isBlob(this.body) ? this.body.stream() : this.body
+
+    /* istanbul ignore if: should never happen */
+    if (!Minipass.isStream(upstream))
+      return Promise.resolve(Buffer.alloc(0))
+
+    const stream = this.size && upstream instanceof MinipassSized ? upstream
+      : !this.size && upstream instanceof Minipass &&
+        !(upstream instanceof MinipassSized) ? upstream
+      : this.size ? new MinipassSized({ size: this.size })
+      : new Minipass()
+
+    // allow timeout on slow response body
+    const resTimeout = this.timeout ? setTimeout(() => {
+      stream.emit('error', new FetchError(
+        `Response timeout while trying to fetch ${
+          this.url} (over ${this.timeout}ms)`, 'body-timeout'))
+    }, this.timeout) : null
+
+    // do not keep the process open just for this timeout, even
+    // though we expect it'll get cleared eventually.
+    if (resTimeout) {
+      resTimeout.unref()
+    }
+
+    // do the pipe in the promise, because the pipe() can send too much
+    // data through right away and upset the MP Sized object
+    return new Promise((resolve, reject) => {
+      // if the stream is some other kind of stream, then pipe through a MP
+      // so we can collect it more easily.
+      if (stream !== upstream) {
+        upstream.on('error', er => stream.emit('error', er))
+        upstream.pipe(stream)
+      }
+      resolve()
+    }).then(() => stream.concat()).then(buf => {
+      clearTimeout(resTimeout)
+      return buf
+    }).catch(er => {
+      clearTimeout(resTimeout)
+      // request was aborted, reject with this Error
+      if (er.name === 'AbortError' || er.name === 'FetchError')
+        throw er
+      else if (er.name === 'RangeError')
+        throw new FetchError(`Could not create Buffer from response body for ${
+          this.url}: ${er.message}`, 'system', er)
+      else
+        // other errors, such as incorrect content-encoding or content-length
+        throw new FetchError(`Invalid response body while trying to fetch ${
+          this.url}: ${er.message}`, 'system', er)
+    })
+  }
+
+  static clone (instance) {
+    if (instance.bodyUsed)
+      throw new Error('cannot clone body after it is used')
+
+    const body = instance.body
+
+    // check that body is a stream and not form-data object
+    // NB: can't clone the form-data object without having it as a dependency
+    if (Minipass.isStream(body) && typeof body.getBoundary !== 'function') {
+      // create a dedicated tee stream so that we don't lose data
+      // potentially sitting in the body stream's buffer by writing it
+      // immediately to p1 and not having it for p2.
+      const tee = new Minipass()
+      const p1 = new Minipass()
+      const p2 = new Minipass()
+      tee.on('error', er => {
+        p1.emit('error', er)
+        p2.emit('error', er)
+      })
+      body.on('error', er => tee.emit('error', er))
+      tee.pipe(p1)
+      tee.pipe(p2)
+      body.pipe(tee)
+      // set instance body to one fork, return the other
+      instance[INTERNALS].body = p1
+      return p2
+    } else
+      return instance.body
+  }
+
+  static extractContentType (body) {
+    return body === null || body === undefined ? null
+      : typeof body === 'string' ? 'text/plain;charset=UTF-8'
+      : isURLSearchParams(body)
+        ? 'application/x-www-form-urlencoded;charset=UTF-8'
+      : isBlob(body) ? body.type || null
+      : Buffer.isBuffer(body) ? null
+      : Object.prototype.toString.call(body) === '[object ArrayBuffer]' ? null
+      : ArrayBuffer.isView(body) ? null
+      : typeof body.getBoundary === 'function'
+        ? `multipart/form-data;boundary=${body.getBoundary()}`
+      : Minipass.isStream(body) ? null
+      : 'text/plain;charset=UTF-8'
+  }
+
+  static getTotalBytes (instance) {
+    const {body} = instance
+    return (body === null || body === undefined) ? 0
+    : isBlob(body) ? body.size
+    : Buffer.isBuffer(body) ? body.length
+    : body && typeof body.getLengthSync === 'function' && (
+        // detect form data input from form-data module
+        body._lengthRetrievers &&
+        /* istanbul ignore next */ body._lengthRetrievers.length == 0 || // 1.x
+        body.hasKnownLength && body.hasKnownLength()) // 2.x
+      ? body.getLengthSync()
+    : null
+  }
+
+  static writeToStream (dest, instance) {
+    const {body} = instance
+
+    if (body === null || body === undefined)
+      dest.end()
+    else if (Buffer.isBuffer(body) || typeof body === 'string')
+      dest.end(body)
+    else {
+      // body is stream or blob
+      const stream = isBlob(body) ? body.stream() : body
+      stream.on('error', er => dest.emit('error', er)).pipe(dest)
+    }
+
+    return dest
+  }
+}
+
+Object.defineProperties(Body.prototype, {
+  body: { enumerable: true },
+  bodyUsed: { enumerable: true },
+  arrayBuffer: { enumerable: true },
+  blob: { enumerable: true },
+  json: { enumerable: true },
+  text: { enumerable: true }
+})
+
+
+const isURLSearchParams = obj =>
+  // Duck-typing as a necessary condition.
+  (typeof obj !== 'object' ||
+    typeof obj.append !== 'function' ||
+    typeof obj.delete !== 'function' ||
+    typeof obj.get !== 'function' ||
+    typeof obj.getAll !== 'function' ||
+    typeof obj.has !== 'function' ||
+    typeof obj.set !== 'function') ? false
+  // Brand-checking and more duck-typing as optional condition.
+  : obj.constructor.name === 'URLSearchParams' ||
+    Object.prototype.toString.call(obj) === '[object URLSearchParams]' ||
+    typeof obj.sort === 'function'
+
+const isBlob = obj =>
+  typeof obj === 'object' &&
+  typeof obj.arrayBuffer === 'function' &&
+  typeof obj.type === 'string' &&
+  typeof obj.stream === 'function' &&
+  typeof obj.constructor === 'function' &&
+  typeof obj.constructor.name === 'string' &&
+  /^(Blob|File)$/.test(obj.constructor.name) &&
+  /^(Blob|File)$/.test(obj[Symbol.toStringTag])
+
+
+const convertBody = (buffer, headers) => {
+  /* istanbul ignore if */
+  if (typeof convert !== 'function')
+    throw new Error('The package `encoding` must be installed to use the textConverted() function')
+
+  const ct = headers && headers.get('content-type')
+  let charset = 'utf-8'
+  let res, str
+
+  // header
+  if (ct)
+    res = /charset=([^;]*)/i.exec(ct)
+
+  // no charset in content type, peek at response body for at most 1024 bytes
+  str = buffer.slice(0, 1024).toString()
+
+  // html5
+  if (!res && str)
+    res = /<meta.+?charset=(['"])(.+?)\1/i.exec(str)
+
+  // html4
+  if (!res && str) {
+    res = /<meta[\s]+?http-equiv=(['"])content-type\1[\s]+?content=(['"])(.+?)\2/i.exec(str)
+
+    if (!res) {
+      res = /<meta[\s]+?content=(['"])(.+?)\1[\s]+?http-equiv=(['"])content-type\3/i.exec(str)
+      if (res)
+        res.pop() // drop last quote
+    }
+
+    if (res)
+      res = /charset=(.*)/i.exec(res.pop())
+  }
+
+  // xml
+  if (!res && str)
+    res = /<\?xml.+?encoding=(['"])(.+?)\1/i.exec(str)
+
+  // found charset
+  if (res) {
+    charset = res.pop()
+
+    // prevent decode issues when sites use incorrect encoding
+    // ref: https://hsivonen.fi/encoding-menu/
+    if (charset === 'gb2312' || charset === 'gbk')
+      charset = 'gb18030'
+  }
+
+  // turn raw buffers into a single utf-8 buffer
+  return convert(
+    buffer,
+    'UTF-8',
+    charset
+  ).toString()
+}
+
+module.exports = Body
diff --git a/server/node_modules/minipass-fetch/lib/fetch-error.js b/server/node_modules/minipass-fetch/lib/fetch-error.js
new file mode 100644
index 0000000..b0445cf
--- /dev/null
+++ b/server/node_modules/minipass-fetch/lib/fetch-error.js
@@ -0,0 +1,31 @@
+'use strict'
+class FetchError extends Error {
+  constructor (message, type, systemError) {
+    super(message)
+    this.code = 'FETCH_ERROR'
+
+    // pick up code, expected, path, ...
+    if (systemError)
+      Object.assign(this, systemError)
+
+    this.errno = this.code
+
+    // override anything the system error might've clobbered
+    this.type = this.code === 'EBADSIZE' && this.found > this.expect
+      ? 'max-size' : type
+    this.message = message
+    Error.captureStackTrace(this, this.constructor)
+  }
+
+  get name () {
+    return 'FetchError'
+  }
+
+  // don't allow name to be overwritten
+  set name (n) {}
+
+  get [Symbol.toStringTag] () {
+    return 'FetchError'
+  }
+}
+module.exports = FetchError
diff --git a/server/node_modules/minipass-fetch/lib/headers.js b/server/node_modules/minipass-fetch/lib/headers.js
new file mode 100644
index 0000000..233675f
--- /dev/null
+++ b/server/node_modules/minipass-fetch/lib/headers.js
@@ -0,0 +1,250 @@
+'use strict'
+const invalidTokenRegex = /[^\^_`a-zA-Z\-0-9!#$%&'*+.|~]/
+const invalidHeaderCharRegex = /[^\t\x20-\x7e\x80-\xff]/
+
+const validateName = name => {
+  name = `${name}`
+  if (invalidTokenRegex.test(name) || name === '')
+    throw new TypeError(`${name} is not a legal HTTP header name`)
+}
+
+const validateValue = value => {
+  value = `${value}`
+  if (invalidHeaderCharRegex.test(value))
+    throw new TypeError(`${value} is not a legal HTTP header value`)
+}
+
+const find = (map, name) => {
+  name = name.toLowerCase()
+  for (const key in map) {
+    if (key.toLowerCase() === name)
+      return key
+  }
+  return undefined
+}
+
+const MAP = Symbol('map')
+class Headers {
+  constructor (init = undefined) {
+    this[MAP] = Object.create(null)
+    if (init instanceof Headers) {
+      const rawHeaders = init.raw()
+      const headerNames = Object.keys(rawHeaders)
+      for (const headerName of headerNames) {
+        for (const value of rawHeaders[headerName]) {
+          this.append(headerName, value)
+        }
+      }
+      return
+    }
+
+    // no-op
+    if (init === undefined || init === null)
+      return
+
+    if (typeof init === 'object') {
+      const method = init[Symbol.iterator]
+      if (method !== null && method !== undefined) {
+        if (typeof method !== 'function')
+          throw new TypeError('Header pairs must be iterable')
+
+        // sequence<sequence<ByteString>>
+        // Note: per spec we have to first exhaust the lists then process them
+        const pairs = []
+        for (const pair of init) {
+          if (typeof pair !== 'object' ||
+              typeof pair[Symbol.iterator] !== 'function')
+            throw new TypeError('Each header pair must be iterable')
+          const arrPair = Array.from(pair)
+          if (arrPair.length !== 2)
+            throw new TypeError('Each header pair must be a name/value tuple')
+          pairs.push(arrPair)
+        }
+
+        for (const pair of pairs) {
+          this.append(pair[0], pair[1])
+        }
+      } else {
+        // record<ByteString, ByteString>
+        for (const key of Object.keys(init)) {
+          this.append(key, init[key])
+        }
+      }
+    } else
+      throw new TypeError('Provided initializer must be an object')
+  }
+
+  get (name) {
+    name = `${name}`
+    validateName(name)
+    const key = find(this[MAP], name)
+    if (key === undefined)
+      return null
+
+    return this[MAP][key].join(', ')
+  }
+
+  forEach (callback, thisArg = undefined) {
+    let pairs = getHeaders(this)
+    for (let i = 0; i < pairs.length; i++) {
+      const [name, value] = pairs[i]
+      callback.call(thisArg, value, name, this)
+      // refresh in case the callback added more headers
+      pairs = getHeaders(this)
+    }
+  }
+
+  set (name, value) {
+    name = `${name}`
+    value = `${value}`
+    validateName(name)
+    validateValue(value)
+    const key = find(this[MAP], name)
+    this[MAP][key !== undefined ? key : name] = [value]
+  }
+
+  append (name, value) {
+    name = `${name}`
+    value = `${value}`
+    validateName(name)
+    validateValue(value)
+    const key = find(this[MAP], name)
+    if (key !== undefined)
+      this[MAP][key].push(value)
+    else
+      this[MAP][name] = [value]
+  }
+
+  has (name) {
+    name = `${name}`
+    validateName(name)
+    return find(this[MAP], name) !== undefined
+  }
+
+  delete (name) {
+    name = `${name}`
+    validateName(name)
+    const key = find(this[MAP], name)
+    if (key !== undefined)
+      delete this[MAP][key]
+  }
+
+  raw () {
+    return this[MAP]
+  }
+
+  keys () {
+    return new HeadersIterator(this, 'key')
+  }
+
+  values () {
+    return new HeadersIterator(this, 'value')
+  }
+
+  [Symbol.iterator]() {
+    return new HeadersIterator(this, 'key+value')
+  }
+
+  entries () {
+    return new HeadersIterator(this, 'key+value')
+  }
+
+  get [Symbol.toStringTag] () {
+    return 'Headers'
+  }
+
+  static exportNodeCompatibleHeaders (headers) {
+    const obj = Object.assign(Object.create(null), headers[MAP])
+
+    // http.request() only supports string as Host header. This hack makes
+    // specifying custom Host header possible.
+    const hostHeaderKey = find(headers[MAP], 'Host')
+    if (hostHeaderKey !== undefined)
+      obj[hostHeaderKey] = obj[hostHeaderKey][0]
+
+    return obj
+  }
+
+  static createHeadersLenient (obj) {
+    const headers = new Headers()
+    for (const name of Object.keys(obj)) {
+      if (invalidTokenRegex.test(name))
+        continue
+
+      if (Array.isArray(obj[name])) {
+        for (const val of obj[name]) {
+          if (invalidHeaderCharRegex.test(val))
+            continue
+
+          if (headers[MAP][name] === undefined)
+            headers[MAP][name] = [val]
+          else
+            headers[MAP][name].push(val)
+        }
+      } else if (!invalidHeaderCharRegex.test(obj[name]))
+        headers[MAP][name] = [obj[name]]
+    }
+    return headers
+  }
+}
+
+Object.defineProperties(Headers.prototype, {
+  get: { enumerable: true },
+  forEach: { enumerable: true },
+  set: { enumerable: true },
+  append: { enumerable: true },
+  has: { enumerable: true },
+  delete: { enumerable: true },
+  keys: { enumerable: true },
+  values: { enumerable: true },
+  entries: { enumerable: true },
+})
+
+const getHeaders = (headers, kind = 'key+value') =>
+  Object.keys(headers[MAP]).sort().map(
+    kind === 'key' ? k => k.toLowerCase()
+    : kind === 'value' ? k => headers[MAP][k].join(', ')
+    : k => [k.toLowerCase(), headers[MAP][k].join(', ')]
+  )
+
+const INTERNAL = Symbol('internal')
+
+class HeadersIterator {
+  constructor (target, kind) {
+    this[INTERNAL] = {
+      target,
+      kind,
+      index: 0,
+    }
+  }
+
+  get [Symbol.toStringTag] () {
+    return 'HeadersIterator'
+  }
+
+  next () {
+    /* istanbul ignore if: should be impossible */
+    if (!this || Object.getPrototypeOf(this) !== HeadersIterator.prototype)
+      throw new TypeError('Value of `this` is not a HeadersIterator')
+
+    const { target, kind, index } = this[INTERNAL]
+    const values = getHeaders(target, kind)
+    const len = values.length
+    if (index >= len) {
+      return {
+        value: undefined,
+        done: true,
+      }
+    }
+
+    this[INTERNAL].index++
+
+    return { value: values[index], done: false }
+  }
+}
+
+// manually extend because 'extends' requires a ctor
+Object.setPrototypeOf(HeadersIterator.prototype,
+  Object.getPrototypeOf(Object.getPrototypeOf([][Symbol.iterator]())))
+
+module.exports = Headers
diff --git a/server/node_modules/minipass-fetch/lib/index.js b/server/node_modules/minipass-fetch/lib/index.js
new file mode 100644
index 0000000..2ffcba8
--- /dev/null
+++ b/server/node_modules/minipass-fetch/lib/index.js
@@ -0,0 +1,341 @@
+'use strict'
+const Url = require('url')
+const http = require('http')
+const https = require('https')
+const zlib = require('minizlib')
+const Minipass = require('minipass')
+
+const Body = require('./body.js')
+const { writeToStream, getTotalBytes } = Body
+const Response = require('./response.js')
+const Headers = require('./headers.js')
+const { createHeadersLenient } = Headers
+const Request = require('./request.js')
+const { getNodeRequestOptions } = Request
+const FetchError = require('./fetch-error.js')
+const AbortError = require('./abort-error.js')
+
+const resolveUrl = Url.resolve
+
+const fetch = (url, opts) => {
+  if (/^data:/.test(url)) {
+    const request = new Request(url, opts)
+    try {
+      const split = url.split(',')
+      const data = Buffer.from(split[1], 'base64')
+      const type = split[0].match(/^data:(.*);base64$/)[1]
+      return Promise.resolve(new Response(data, {
+        headers: {
+          'Content-Type': type,
+          'Content-Length': data.length,
+        }
+      }))
+    } catch (er) {
+      return Promise.reject(new FetchError(`[${request.method}] ${
+        request.url} invalid URL, ${er.message}`, 'system', er))
+    }
+  }
+
+  return new Promise((resolve, reject) => {
+    // build request object
+    const request = new Request(url, opts)
+    let options
+    try {
+      options = getNodeRequestOptions(request)
+    } catch (er) {
+      return reject(er)
+    }
+
+    const send = (options.protocol === 'https:' ? https : http).request
+    const { signal } = request
+    let response = null
+    const abort = () => {
+      const error = new AbortError('The user aborted a request.')
+      reject(error)
+      if (Minipass.isStream(request.body) &&
+          typeof request.body.destroy === 'function') {
+        request.body.destroy(error)
+      }
+      if (response && response.body) {
+        response.body.emit('error', error)
+      }
+    }
+
+    if (signal && signal.aborted)
+      return abort()
+
+    const abortAndFinalize = () => {
+      abort()
+      finalize()
+    }
+
+    const finalize = () => {
+      req.abort()
+      if (signal)
+        signal.removeEventListener('abort', abortAndFinalize)
+      clearTimeout(reqTimeout)
+    }
+
+    // send request
+    const req = send(options)
+
+    if (signal)
+      signal.addEventListener('abort', abortAndFinalize)
+
+    let reqTimeout = null
+    if (request.timeout) {
+      req.once('socket', socket => {
+        reqTimeout = setTimeout(() => {
+          reject(new FetchError(`network timeout at: ${
+            request.url}`, 'request-timeout'))
+          finalize()
+        }, request.timeout)
+      })
+    }
+
+    req.on('error', er => {
+      // if a 'response' event is emitted before the 'error' event, then by the
+      // time this handler is run it's too late to reject the Promise for the
+      // response. instead, we forward the error event to the response stream
+      // so that the error will surface to the user when they try to consume
+      // the body. this is done as a side effect of aborting the request except
+      // for in windows, where we must forward the event manually, otherwise
+      // there is no longer a ref'd socket attached to the request and the
+      // stream never ends so the event loop runs out of work and the process
+      // exits without warning.
+      // coverage skipped here due to the difficulty in testing
+      // istanbul ignore next
+      if (req.res)
+        req.res.emit('error', er)
+      reject(new FetchError(`request to ${request.url} failed, reason: ${
+        er.message}`, 'system', er))
+      finalize()
+    })
+
+    req.on('response', res => {
+      clearTimeout(reqTimeout)
+
+      const headers = createHeadersLenient(res.headers)
+
+      // HTTP fetch step 5
+      if (fetch.isRedirect(res.statusCode)) {
+        // HTTP fetch step 5.2
+        const location = headers.get('Location')
+
+        // HTTP fetch step 5.3
+        const locationURL = location === null ? null
+          : resolveUrl(request.url, location)
+
+        // HTTP fetch step 5.5
+        switch (request.redirect) {
+          case 'error':
+            reject(new FetchError(`uri requested responds with a redirect, redirect mode is set to error: ${
+              request.url}`, 'no-redirect'))
+            finalize()
+            return
+
+          case 'manual':
+            // node-fetch-specific step: make manual redirect a bit easier to
+            // use by setting the Location header value to the resolved URL.
+            if (locationURL !== null) {
+              // handle corrupted header
+              try {
+                headers.set('Location', locationURL)
+              } catch (err) {
+                /* istanbul ignore next: nodejs server prevent invalid
+                   response headers, we can't test this through normal
+                   request */
+                reject(err)
+              }
+            }
+            break
+
+          case 'follow':
+            // HTTP-redirect fetch step 2
+            if (locationURL === null) {
+              break
+            }
+
+            // HTTP-redirect fetch step 5
+            if (request.counter >= request.follow) {
+              reject(new FetchError(`maximum redirect reached at: ${
+                request.url}`, 'max-redirect'))
+              finalize()
+              return
+            }
+
+            // HTTP-redirect fetch step 9
+            if (res.statusCode !== 303 &&
+                request.body &&
+                getTotalBytes(request) === null) {
+              reject(new FetchError(
+                'Cannot follow redirect with body being a readable stream',
+                'unsupported-redirect'
+              ))
+              finalize()
+              return
+            }
+
+            // Update host due to redirection
+            request.headers.set('host', Url.parse(locationURL).host)
+
+            // HTTP-redirect fetch step 6 (counter increment)
+            // Create a new Request object.
+            const requestOpts = {
+              headers: new Headers(request.headers),
+              follow: request.follow,
+              counter: request.counter + 1,
+              agent: request.agent,
+              compress: request.compress,
+              method: request.method,
+              body: request.body,
+              signal: request.signal,
+              timeout: request.timeout,
+            }
+
+            // HTTP-redirect fetch step 11
+            if (res.statusCode === 303 || (
+                (res.statusCode === 301 || res.statusCode === 302) &&
+                request.method === 'POST'
+            )) {
+              requestOpts.method = 'GET'
+              requestOpts.body = undefined
+              requestOpts.headers.delete('content-length')
+            }
+
+            // HTTP-redirect fetch step 15
+            resolve(fetch(new Request(locationURL, requestOpts)))
+            finalize()
+            return
+        }
+      } // end if(isRedirect)
+
+
+      // prepare response
+      res.once('end', () =>
+        signal && signal.removeEventListener('abort', abortAndFinalize))
+
+      const body = new Minipass()
+      // exceedingly rare that the stream would have an error,
+      // but just in case we proxy it to the stream in use.
+      res.on('error', /* istanbul ignore next */ er => body.emit('error', er))
+      res.on('data', (chunk) => body.write(chunk))
+      res.on('end', () => body.end())
+
+      const responseOptions = {
+        url: request.url,
+        status: res.statusCode,
+        statusText: res.statusMessage,
+        headers: headers,
+        size: request.size,
+        timeout: request.timeout,
+        counter: request.counter,
+        trailer: new Promise(resolve =>
+          res.on('end', () => resolve(createHeadersLenient(res.trailers))))
+      }
+
+      // HTTP-network fetch step 12.1.1.3
+      const codings = headers.get('Content-Encoding')
+
+      // HTTP-network fetch step 12.1.1.4: handle content codings
+
+      // in following scenarios we ignore compression support
+      // 1. compression support is disabled
+      // 2. HEAD request
+      // 3. no Content-Encoding header
+      // 4. no content response (204)
+      // 5. content not modified response (304)
+      if (!request.compress ||
+          request.method === 'HEAD' ||
+          codings === null ||
+          res.statusCode === 204 ||
+          res.statusCode === 304) {
+        response = new Response(body, responseOptions)
+        resolve(response)
+        return
+      }
+
+
+      // Be less strict when decoding compressed responses, since sometimes
+      // servers send slightly invalid responses that are still accepted
+      // by common browsers.
+      // Always using Z_SYNC_FLUSH is what cURL does.
+      const zlibOptions = {
+        flush: zlib.constants.Z_SYNC_FLUSH,
+        finishFlush: zlib.constants.Z_SYNC_FLUSH,
+      }
+
+      // for gzip
+      if (codings == 'gzip' || codings == 'x-gzip') {
+        const unzip = new zlib.Gunzip(zlibOptions)
+        response = new Response(
+          // exceedingly rare that the stream would have an error,
+          // but just in case we proxy it to the stream in use.
+          body.on('error', /* istanbul ignore next */ er => unzip.emit('error', er)).pipe(unzip),
+          responseOptions
+        )
+        resolve(response)
+        return
+      }
+
+      // for deflate
+      if (codings == 'deflate' || codings == 'x-deflate') {
+        // handle the infamous raw deflate response from old servers
+        // a hack for old IIS and Apache servers
+        const raw = res.pipe(new Minipass())
+        raw.once('data', chunk => {
+          // see http://stackoverflow.com/questions/37519828
+          const decoder = (chunk[0] & 0x0F) === 0x08
+            ? new zlib.Inflate()
+            : new zlib.InflateRaw()
+          // exceedingly rare that the stream would have an error,
+          // but just in case we proxy it to the stream in use.
+          body.on('error', /* istanbul ignore next */ er => decoder.emit('error', er)).pipe(decoder)
+          response = new Response(decoder, responseOptions)
+          resolve(response)
+        })
+        return
+      }
+
+
+      // for br
+      if (codings == 'br') {
+        // ignoring coverage so tests don't have to fake support (or lack of) for brotli
+        // istanbul ignore next
+        try {
+          var decoder = new zlib.BrotliDecompress()
+        } catch (err) {
+          reject(err)
+          finalize()
+          return
+        }
+        // exceedingly rare that the stream would have an error,
+        // but just in case we proxy it to the stream in use.
+        body.on('error', /* istanbul ignore next */ er => decoder.emit('error', er)).pipe(decoder)
+        response = new Response(decoder, responseOptions)
+        resolve(response)
+        return
+      }
+
+      // otherwise, use response as-is
+      response = new Response(body, responseOptions)
+      resolve(response)
+    })
+
+    writeToStream(req, request)
+  })
+}
+
+module.exports = fetch
+
+fetch.isRedirect = code =>
+  code === 301 ||
+  code === 302 ||
+  code === 303 ||
+  code === 307 ||
+  code === 308
+
+fetch.Headers = Headers
+fetch.Request = Request
+fetch.Response = Response
+fetch.FetchError = FetchError
diff --git a/server/node_modules/minipass-fetch/lib/request.js b/server/node_modules/minipass-fetch/lib/request.js
new file mode 100644
index 0000000..278b278
--- /dev/null
+++ b/server/node_modules/minipass-fetch/lib/request.js
@@ -0,0 +1,263 @@
+'use strict'
+const Url = require('url')
+const Minipass = require('minipass')
+const Headers = require('./headers.js')
+const { exportNodeCompatibleHeaders } = Headers
+const Body = require('./body.js')
+const { clone, extractContentType, getTotalBytes } = Body
+
+const version = require('../package.json').version
+const defaultUserAgent =
+  `minipass-fetch/${version} (+https://github.com/isaacs/minipass-fetch)`
+
+const INTERNALS = Symbol('Request internals')
+
+const { parse: parseUrl, format: formatUrl } = Url
+
+const isRequest = input =>
+  typeof input === 'object' && typeof input[INTERNALS] === 'object'
+
+const isAbortSignal = signal => {
+  const proto = (
+    signal
+    && typeof signal === 'object'
+    && Object.getPrototypeOf(signal)
+  )
+  return !!(proto && proto.constructor.name === 'AbortSignal')
+}
+
+class Request extends Body {
+  constructor (input, init = {}) {
+    const parsedURL = isRequest(input) ? Url.parse(input.url)
+      : input && input.href ? Url.parse(input.href)
+      : Url.parse(`${input}`)
+
+    if (isRequest(input))
+      init = { ...input[INTERNALS], ...init }
+    else if (!input || typeof input === 'string')
+      input = {}
+
+    const method = (init.method || input.method || 'GET').toUpperCase()
+    const isGETHEAD = method === 'GET' || method === 'HEAD'
+
+    if ((init.body !== null && init.body !== undefined ||
+        isRequest(input) && input.body !== null) && isGETHEAD)
+      throw new TypeError('Request with GET/HEAD method cannot have body')
+
+    const inputBody = init.body !== null && init.body !== undefined ? init.body
+      : isRequest(input) && input.body !== null ? clone(input)
+      : null
+
+    super(inputBody, {
+      timeout: init.timeout || input.timeout || 0,
+      size: init.size || input.size || 0,
+    })
+
+    const headers = new Headers(init.headers || input.headers || {})
+
+    if (inputBody !== null && inputBody !== undefined &&
+        !headers.has('Content-Type')) {
+      const contentType = extractContentType(inputBody)
+      if (contentType)
+        headers.append('Content-Type', contentType)
+    }
+
+    const signal = 'signal' in init ? init.signal
+      : null
+
+    if (signal !== null && signal !== undefined && !isAbortSignal(signal))
+      throw new TypeError('Expected signal must be an instanceof AbortSignal')
+
+    // TLS specific options that are handled by node
+    const {
+      ca,
+      cert,
+      ciphers,
+      clientCertEngine,
+      crl,
+      dhparam,
+      ecdhCurve,
+      family,
+      honorCipherOrder,
+      key,
+      passphrase,
+      pfx,
+      rejectUnauthorized = process.env.NODE_TLS_REJECT_UNAUTHORIZED !== '0',
+      secureOptions,
+      secureProtocol,
+      servername,
+      sessionIdContext,
+    } = init
+
+    this[INTERNALS] = {
+      method,
+      redirect: init.redirect || input.redirect || 'follow',
+      headers,
+      parsedURL,
+      signal,
+      ca,
+      cert,
+      ciphers,
+      clientCertEngine,
+      crl,
+      dhparam,
+      ecdhCurve,
+      family,
+      honorCipherOrder,
+      key,
+      passphrase,
+      pfx,
+      rejectUnauthorized,
+      secureOptions,
+      secureProtocol,
+      servername,
+      sessionIdContext,
+    }
+
+    // node-fetch-only options
+    this.follow = init.follow !== undefined ? init.follow
+      : input.follow !== undefined ? input.follow
+      : 20
+    this.compress = init.compress !== undefined ? init.compress
+      : input.compress !== undefined ? input.compress
+      : true
+    this.counter = init.counter || input.counter || 0
+    this.agent = init.agent || input.agent
+  }
+
+  get method() {
+    return this[INTERNALS].method
+  }
+
+  get url() {
+    return formatUrl(this[INTERNALS].parsedURL)
+  }
+
+  get headers() {
+    return this[INTERNALS].headers
+  }
+
+  get redirect() {
+    return this[INTERNALS].redirect
+  }
+
+  get signal() {
+    return this[INTERNALS].signal
+  }
+
+  clone () {
+    return new Request(this)
+  }
+
+  get [Symbol.toStringTag] () {
+    return 'Request'
+  }
+
+  static getNodeRequestOptions (request) {
+    const parsedURL = request[INTERNALS].parsedURL
+    const headers = new Headers(request[INTERNALS].headers)
+
+    // fetch step 1.3
+    if (!headers.has('Accept'))
+      headers.set('Accept', '*/*')
+
+    // Basic fetch
+    if (!parsedURL.protocol || !parsedURL.hostname)
+      throw new TypeError('Only absolute URLs are supported')
+
+    if (!/^https?:$/.test(parsedURL.protocol))
+      throw new TypeError('Only HTTP(S) protocols are supported')
+
+    if (request.signal &&
+        Minipass.isStream(request.body) &&
+        typeof request.body.destroy !== 'function') {
+      throw new Error(
+        'Cancellation of streamed requests with AbortSignal is not supported')
+    }
+
+    // HTTP-network-or-cache fetch steps 2.4-2.7
+    const contentLengthValue =
+      (request.body === null || request.body === undefined) &&
+        /^(POST|PUT)$/i.test(request.method) ? '0'
+      : request.body !== null && request.body !== undefined
+        ? getTotalBytes(request)
+      : null
+
+    if (contentLengthValue)
+      headers.set('Content-Length', contentLengthValue + '')
+
+    // HTTP-network-or-cache fetch step 2.11
+    if (!headers.has('User-Agent'))
+      headers.set('User-Agent', defaultUserAgent)
+
+    // HTTP-network-or-cache fetch step 2.15
+    if (request.compress && !headers.has('Accept-Encoding'))
+      headers.set('Accept-Encoding', 'gzip,deflate')
+
+    const agent = typeof request.agent === 'function'
+      ? request.agent(parsedURL)
+      : request.agent
+
+    if (!headers.has('Connection') && !agent)
+      headers.set('Connection', 'close')
+
+    // TLS specific options that are handled by node
+    const {
+      ca,
+      cert,
+      ciphers,
+      clientCertEngine,
+      crl,
+      dhparam,
+      ecdhCurve,
+      family,
+      honorCipherOrder,
+      key,
+      passphrase,
+      pfx,
+      rejectUnauthorized,
+      secureOptions,
+      secureProtocol,
+      servername,
+      sessionIdContext,
+    } = request[INTERNALS]
+
+    // HTTP-network fetch step 4.2
+    // chunked encoding is handled by Node.js
+
+    return {
+      ...parsedURL,
+      method: request.method,
+      headers: exportNodeCompatibleHeaders(headers),
+      agent,
+      ca,
+      cert,
+      ciphers,
+      clientCertEngine,
+      crl,
+      dhparam,
+      ecdhCurve,
+      family,
+      honorCipherOrder,
+      key,
+      passphrase,
+      pfx,
+      rejectUnauthorized,
+      secureOptions,
+      secureProtocol,
+      servername,
+      sessionIdContext,
+    }
+  }
+}
+
+module.exports = Request
+
+Object.defineProperties(Request.prototype, {
+  method: { enumerable: true },
+  url: { enumerable: true },
+  headers: { enumerable: true },
+  redirect: { enumerable: true },
+  clone: { enumerable: true },
+  signal: { enumerable: true },
+})
diff --git a/server/node_modules/minipass-fetch/lib/response.js b/server/node_modules/minipass-fetch/lib/response.js
new file mode 100644
index 0000000..854f789
--- /dev/null
+++ b/server/node_modules/minipass-fetch/lib/response.js
@@ -0,0 +1,89 @@
+'use strict'
+const http = require('http')
+const { STATUS_CODES } = http
+
+const Headers = require('./headers.js')
+const Body = require('./body.js')
+const { clone, extractContentType } = Body
+
+const INTERNALS = Symbol('Response internals')
+
+class Response extends Body {
+  constructor (body = null, opts = {}) {
+    super(body, opts)
+
+    const status = opts.status || 200
+    const headers = new Headers(opts.headers)
+
+    if (body !== null && body !== undefined && !headers.has('Content-Type')) {
+      const contentType = extractContentType(body)
+      if (contentType)
+        headers.append('Content-Type', contentType)
+    }
+
+    this[INTERNALS] = {
+      url: opts.url,
+      status,
+      statusText: opts.statusText || STATUS_CODES[status],
+      headers,
+      counter: opts.counter,
+      trailer: Promise.resolve(opts.trailer || new Headers()),
+    }
+  }
+
+  get trailer () {
+    return this[INTERNALS].trailer
+  }
+
+  get url () {
+    return this[INTERNALS].url || ''
+  }
+
+  get status () {
+    return this[INTERNALS].status
+  }
+
+  get ok ()  {
+    return this[INTERNALS].status >= 200 && this[INTERNALS].status < 300
+  }
+
+  get redirected () {
+    return this[INTERNALS].counter > 0
+  }
+
+  get statusText () {
+    return this[INTERNALS].statusText
+  }
+
+  get headers () {
+    return this[INTERNALS].headers
+  }
+
+  clone () {
+    return new Response(clone(this), {
+      url: this.url,
+      status: this.status,
+      statusText: this.statusText,
+      headers: this.headers,
+      ok: this.ok,
+      redirected: this.redirected,
+      trailer: this.trailer,
+    })
+  }
+
+  get [Symbol.toStringTag] () {
+    return 'Response'
+  }
+}
+
+module.exports = Response
+
+Object.defineProperties(Response.prototype, {
+  url: { enumerable: true },
+  status: { enumerable: true },
+  ok: { enumerable: true },
+  redirected: { enumerable: true },
+  statusText: { enumerable: true },
+  headers: { enumerable: true },
+  clone: { enumerable: true },
+})
diff --git a/server/node_modules/minipass-fetch/package.json b/server/node_modules/minipass-fetch/package.json
new file mode 100644
index 0000000..1d7d9e4
--- /dev/null
+++ b/server/node_modules/minipass-fetch/package.json
@@ -0,0 +1,53 @@
+{
+  "name": "minipass-fetch",
+  "version": "1.4.1",
+  "description": "An implementation of window.fetch in Node.js using Minipass streams",
+  "license": "MIT",
+  "main": "lib/index.js",
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "tap": {
+    "coverage-map": "map.js",
+    "check-coverage": true
+  },
+  "devDependencies": {
+    "@ungap/url-search-params": "^0.1.2",
+    "abort-controller": "^3.0.0",
+    "abortcontroller-polyfill": "~1.3.0",
+    "form-data": "^2.5.1",
+    "parted": "^0.1.1",
+    "string-to-arraybuffer": "^1.0.2",
+    "tap": "^15.0.9",
+    "whatwg-url": "^7.0.0"
+  },
+  "dependencies": {
+    "minipass": "^3.1.0",
+    "minipass-sized": "^1.0.3",
+    "minizlib": "^2.0.0"
+  },
+  "optionalDependencies": {
+    "encoding": "^0.1.12"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/npm/minipass-fetch.git"
+  },
+  "keywords": [
+    "fetch",
+    "minipass",
+    "node-fetch",
+    "window.fetch"
+  ],
+  "files": [
+    "index.js",
+    "lib/*.js"
+  ],
+  "engines": {
+    "node": ">=8"
+  }
+}
diff --git a/server/node_modules/minipass-flush/LICENSE b/server/node_modules/minipass-flush/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/minipass-flush/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/minipass-flush/README.md b/server/node_modules/minipass-flush/README.md
new file mode 100644
index 0000000..7eea400
--- /dev/null
+++ b/server/node_modules/minipass-flush/README.md
@@ -0,0 +1,47 @@
+# minipass-flush
+
+A Minipass stream that calls a flush function before emitting 'end'
+
+## USAGE
+
+```js
+const Flush = require('minipass-flush')
+cons f = new Flush({
+  flush (cb) {
+    // call the cb when done, or return a promise
+    // the 'end' event will wait for it, along with
+    // close, finish, and prefinish.
+    // call the cb with an error, or return a rejecting
+    // promise to emit 'error' instead of doing the 'end'
+    return rerouteAllEncryptions().then(() => clearAllChannels())
+  },
+  // all other minipass options accepted as well
+})
+
+someDataSource.pipe(f).on('end', () => {
+  // proper flushing has been accomplished
+})
+
+// Or as a subclass implementing a 'flush' method:
+class MyFlush extends Flush {
+  flush (cb) {
+    // old fashioned callback style!
+    rerouteAllEncryptions(er => {
+      if (er)
+        return cb(er)
+      clearAllChannels(er => {
+        if (er)
+          cb(er)
+        cb()
+      })
+    })
+  }
+}
+```
+
+That's about it.
+
+If your `flush` method doesn't have to do anything asynchronous, then it's
+better to call the callback right away in this tick, rather than returning
+`Promise.resolve()`, so that the `end` event can happen as soon as
+possible.
diff --git a/server/node_modules/minipass-flush/index.js b/server/node_modules/minipass-flush/index.js
new file mode 100644
index 0000000..cb2537f
--- /dev/null
+++ b/server/node_modules/minipass-flush/index.js
@@ -0,0 +1,39 @@
+const Minipass = require('minipass')
+const _flush = Symbol('_flush')
+const _flushed = Symbol('_flushed')
+const _flushing = Symbol('_flushing')
+class Flush extends Minipass {
+  constructor (opt = {}) {
+    if (typeof opt === 'function')
+      opt = { flush: opt }
+
+    super(opt)
+
+    // or extend this class and provide a 'flush' method in your subclass
+    if (typeof opt.flush !== 'function' && typeof this.flush !== 'function')
+      throw new TypeError('must provide flush function in options')
+
+    this[_flush] = opt.flush || this.flush
+  }
+
+  emit (ev, ...data) {
+    if ((ev !== 'end' && ev !== 'finish') || this[_flushed])
+      return super.emit(ev, ...data)
+
+    if (this[_flushing])
+      return
+
+    this[_flushing] = true
+
+    const afterFlush = er => {
+      this[_flushed] = true
+      er ? super.emit('error', er) : super.emit('end')
+    }
+
+    const ret = this[_flush](afterFlush)
+    if (ret && ret.then)
+      ret.then(() => afterFlush(), er => afterFlush(er))
+  }
+}
+
+module.exports = Flush
diff --git a/server/node_modules/minipass-flush/package.json b/server/node_modules/minipass-flush/package.json
new file mode 100644
index 0000000..09127d0
--- /dev/null
+++ b/server/node_modules/minipass-flush/package.json
@@ -0,0 +1,39 @@
+{
+  "name": "minipass-flush",
+  "version": "1.0.5",
+  "description": "A Minipass stream that calls a flush function before emitting 'end'",
+  "author": "Isaac Z. Schlueter <i@izs.me> (https://izs.me)",
+  "license": "ISC",
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "tap": {
+    "check-coverage": true
+  },
+  "devDependencies": {
+    "tap": "^14.6.9"
+  },
+  "dependencies": {
+    "minipass": "^3.0.0"
+  },
+  "files": [
+    "index.js"
+  ],
+  "main": "index.js",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/isaacs/minipass-flush.git"
+  },
+  "keywords": [
+    "minipass",
+    "flush",
+    "stream"
+  ],
+  "engines": {
+    "node": ">= 8"
+  }
+}
diff --git a/server/node_modules/minipass-pipeline/LICENSE b/server/node_modules/minipass-pipeline/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/minipass-pipeline/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/minipass-pipeline/README.md b/server/node_modules/minipass-pipeline/README.md
new file mode 100644
index 0000000..12daa99
--- /dev/null
+++ b/server/node_modules/minipass-pipeline/README.md
@@ -0,0 +1,69 @@
+# minipass-pipeline
+
+Create a pipeline of streams using Minipass.
+
+Calls `.pipe()` on all the streams in the list.  Returns a stream where
+writes got to the first pipe in the chain, and reads are from the last.
+
+Errors are proxied along the chain and emitted on the Pipeline stream.
+
+## USAGE
+
+```js
+const Pipeline = require('minipass-pipeline')
+
+// the list of streams to pipeline together,
+// a bit like `input | transform | output` in bash
+const p = new Pipeline(input, transform, output)
+
+p.write('foo') // writes to input
+p.on('data', chunk => doSomething()) // reads from output stream
+
+// less contrived example (but still pretty contrived)...
+const decode = new bunzipDecoder()
+const unpack = tar.extract({ cwd: 'target-dir' })
+const tbz = new Pipeline(decode, unpack)
+
+fs.createReadStream('archive.tbz').pipe(tbz)
+
+// specify any minipass options if you like, as the first argument
+// it'll only try to pipeline event emitters with a .pipe() method
+const p = new Pipeline({ objectMode: true }, input, transform, output)
+
+// If you don't know the things to pipe in right away, that's fine.
+// use p.push(stream) to add to the end, or p.unshift(stream) to the front
+const databaseDecoderStreamDoohickey = (connectionInfo) => {
+  const p = new Pipeline()
+  logIntoDatabase(connectionInfo).then(connection => {
+    initializeDecoderRing(connectionInfo).then(decoderRing => {
+      p.push(connection, decoderRing)
+      getUpstreamSource(upstream => {
+        p.unshift(upstream)
+      })
+    })
+  })
+  // return to caller right away
+  // emitted data will be upstream -> connection -> decoderRing pipeline
+  return p
+}
+```
+
+Pipeline is a [minipass](http://npm.im/minipass) stream, so it's as
+synchronous as the streams it wraps.  It will buffer data until there is a
+reader, but no longer, so make sure to attach your listeners before you
+pipe it somewhere else.
+
+## `new Pipeline(opts = {}, ...streams)`
+
+Create a new Pipeline with the specified Minipass options and any streams
+provided.
+
+## `pipeline.push(stream, ...)`
+
+Attach one or more streams to the pipeline at the end (read) side of the
+pipe chain.
+
+## `pipeline.unshift(stream, ...)`
+
+Attach one or more streams to the pipeline at the start (write) side of the
+pipe chain.
diff --git a/server/node_modules/minipass-pipeline/index.js b/server/node_modules/minipass-pipeline/index.js
new file mode 100644
index 0000000..b94ea14
--- /dev/null
+++ b/server/node_modules/minipass-pipeline/index.js
@@ -0,0 +1,128 @@
+const Minipass = require('minipass')
+const EE = require('events')
+const isStream = s => s && s instanceof EE && (
+  typeof s.pipe === 'function' || // readable
+  (typeof s.write === 'function' && typeof s.end === 'function') // writable
+)
+
+const _head = Symbol('_head')
+const _tail = Symbol('_tail')
+const _linkStreams = Symbol('_linkStreams')
+const _setHead = Symbol('_setHead')
+const _setTail = Symbol('_setTail')
+const _onError = Symbol('_onError')
+const _onData = Symbol('_onData')
+const _onEnd = Symbol('_onEnd')
+const _onDrain = Symbol('_onDrain')
+const _streams = Symbol('_streams')
+class Pipeline extends Minipass {
+  constructor (opts, ...streams) {
+    if (isStream(opts)) {
+      streams.unshift(opts)
+      opts = {}
+    }
+
+    super(opts)
+    this[_streams] = []
+    if (streams.length)
+      this.push(...streams)
+  }
+
+  [_linkStreams] (streams) {
+    // reduce takes (left,right), and we return right to make it the
+    // new left value.
+    return streams.reduce((src, dest) => {
+      src.on('error', er => dest.emit('error', er))
+      src.pipe(dest)
+      return dest
+    })
+  }
+
+  push (...streams) {
+    this[_streams].push(...streams)
+    if (this[_tail])
+      streams.unshift(this[_tail])
+
+    const linkRet = this[_linkStreams](streams)
+
+    this[_setTail](linkRet)
+    if (!this[_head])
+      this[_setHead](streams[0])
+  }
+
+  unshift (...streams) {
+    this[_streams].unshift(...streams)
+    if (this[_head])
+      streams.push(this[_head])
+
+    const linkRet = this[_linkStreams](streams)
+    this[_setHead](streams[0])
+    if (!this[_tail])
+      this[_setTail](linkRet)
+  }
+
+  destroy (er) {
+    // set fire to the whole thing.
+    this[_streams].forEach(s =>
+      typeof s.destroy === 'function' && s.destroy())
+    return super.destroy(er)
+  }
+
+  // readable interface -> tail
+  [_setTail] (stream) {
+    this[_tail] = stream
+    stream.on('error', er => this[_onError](stream, er))
+    stream.on('data', chunk => this[_onData](stream, chunk))
+    stream.on('end', () => this[_onEnd](stream))
+    stream.on('finish', () => this[_onEnd](stream))
+  }
+
+  // errors proxied down the pipeline
+  // they're considered part of the "read" interface
+  [_onError] (stream, er) {
+    if (stream === this[_tail])
+      this.emit('error', er)
+  }
+  [_onData] (stream, chunk) {
+    if (stream === this[_tail])
+      super.write(chunk)
+  }
+  [_onEnd] (stream) {
+    if (stream === this[_tail])
+      super.end()
+  }
+  pause () {
+    super.pause()
+    return this[_tail] && this[_tail].pause && this[_tail].pause()
+  }
+
+  // NB: Minipass calls its internal private [RESUME] method during
+  // pipe drains, to avoid hazards where stream.resume() is overridden.
+  // Thus, we need to listen to the resume *event*, not override the
+  // resume() method, and proxy *that* to the tail.
+  emit (ev, ...args) {
+    if (ev === 'resume' && this[_tail] && this[_tail].resume)
+      this[_tail].resume()
+    return super.emit(ev, ...args)
+  }
+
+  // writable interface -> head
+  [_setHead] (stream) {
+    this[_head] = stream
+    stream.on('drain', () => this[_onDrain](stream))
+  }
+  [_onDrain] (stream) {
+    if (stream === this[_head])
+      this.emit('drain')
+  }
+  write (chunk, enc, cb) {
+    return this[_head].write(chunk, enc, cb) &&
+      (this.flowing || this.buffer.length === 0)
+  }
+  end (chunk, enc, cb) {
+    this[_head].end(chunk, enc, cb)
+    return this
+  }
+}
+
+module.exports = Pipeline
diff --git a/server/node_modules/minipass-pipeline/package.json b/server/node_modules/minipass-pipeline/package.json
new file mode 100644
index 0000000..d608dc6
--- /dev/null
+++ b/server/node_modules/minipass-pipeline/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "minipass-pipeline",
+  "version": "1.2.4",
+  "description": "create a pipeline of streams using Minipass",
+  "author": "Isaac Z. Schlueter <i@izs.me> (https://izs.me)",
+  "license": "ISC",
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "tap": {
+    "check-coverage": true
+  },
+  "devDependencies": {
+    "tap": "^14.6.9"
+  },
+  "dependencies": {
+    "minipass": "^3.0.0"
+  },
+  "files": [
+    "index.js"
+  ],
+  "engines": {
+    "node": ">=8"
+  }
+}
diff --git a/server/node_modules/minipass-sized/.npmignore b/server/node_modules/minipass-sized/.npmignore
new file mode 100644
index 0000000..2bec044
--- /dev/null
+++ b/server/node_modules/minipass-sized/.npmignore
@@ -0,0 +1,22 @@
+# ignore most things, include some others
+/*
+/.*
+
+!bin/
+!lib/
+!docs/
+!package.json
+!package-lock.json
+!README.md
+!CONTRIBUTING.md
+!LICENSE
+!CHANGELOG.md
+!example/
+!scripts/
+!tap-snapshots/
+!test/
+!.travis.yml
+!.gitignore
+!.gitattributes
+!coverage-map.js
+!index.js
diff --git a/server/node_modules/minipass-sized/LICENSE b/server/node_modules/minipass-sized/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/minipass-sized/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/minipass-sized/README.md b/server/node_modules/minipass-sized/README.md
new file mode 100644
index 0000000..6da403e
--- /dev/null
+++ b/server/node_modules/minipass-sized/README.md
@@ -0,0 +1,28 @@
+# minipass-sized
+
+A Minipass stream that raises an error if you get a different number of
+bytes than expected.
+
+## USAGE
+
+Use just like any old [minipass](http://npm.im/minipass) stream, but
+provide a `size` option to the constructor.
+
+The `size` option must be a positive integer, smaller than
+`Number.MAX_SAFE_INTEGER`.
+
+```js
+const MinipassSized = require('minipass-sized')
+// figure out how much data you expect to get
+const expectedSize = +headers['content-length']
+const stream = new MinipassSized({ size: expectedSize })
+stream.on('error', er => {
+  // if it's the wrong size, then this will raise an error with
+  // { found: <number>, expect: <number>, code: 'EBADSIZE' }
+})
+response.pipe(stream)
+```
+
+Caveats: this does not work with `objectMode` streams, and will throw a
+`TypeError` from the constructor if the size argument is missing or
+invalid.
diff --git a/server/node_modules/minipass-sized/index.js b/server/node_modules/minipass-sized/index.js
new file mode 100644
index 0000000..a0c8acd
--- /dev/null
+++ b/server/node_modules/minipass-sized/index.js
@@ -0,0 +1,67 @@
+const Minipass = require('minipass')
+
+class SizeError extends Error {
+  constructor (found, expect) {
+    super(`Bad data size: expected ${expect} bytes, but got ${found}`)
+    this.expect = expect
+    this.found = found
+    this.code = 'EBADSIZE'
+	  Error.captureStackTrace(this, this.constructor)
+  }
+  get name () {
+    return 'SizeError'
+  }
+}
+
+class MinipassSized extends Minipass {
+  constructor (options = {}) {
+    super(options)
+
+    if (options.objectMode)
+      throw new TypeError(`${
+        this.constructor.name
+      } streams only work with string and buffer data`)
+
+    this.found = 0
+    this.expect = options.size
+    if (typeof this.expect !== 'number' ||
+        this.expect > Number.MAX_SAFE_INTEGER ||
+        isNaN(this.expect) ||
+        this.expect < 0 ||
+        !isFinite(this.expect) ||
+        this.expect !== Math.floor(this.expect))
+      throw new Error('invalid expected size: ' + this.expect)
+  }
+
+  write (chunk, encoding, cb) {
+    const buffer = Buffer.isBuffer(chunk) ? chunk
+      : typeof chunk === 'string' ?
+        Buffer.from(chunk, typeof encoding === 'string' ? encoding : 'utf8')
+      : chunk
+
+    if (!Buffer.isBuffer(buffer)) {
+      this.emit('error', new TypeError(`${
+        this.constructor.name
+      } streams only work with string and buffer data`))
+      return false
+    }
+
+    this.found += buffer.length
+    if (this.found > this.expect)
+      this.emit('error', new SizeError(this.found, this.expect))
+
+    return super.write(chunk, encoding, cb)
+  }
+
+  emit (ev, ...data) {
+    if (ev === 'end') {
+      if (this.found !== this.expect)
+        this.emit('error', new SizeError(this.found, this.expect))
+    }
+    return super.emit(ev, ...data)
+  }
+}
+
+MinipassSized.SizeError = SizeError
+
+module.exports = MinipassSized
diff --git a/server/node_modules/minipass-sized/package-lock.json b/server/node_modules/minipass-sized/package-lock.json
new file mode 100644
index 0000000..944b285
--- /dev/null
+++ b/server/node_modules/minipass-sized/package-lock.json
@@ -0,0 +1,3464 @@
+{
+  "name": "minipass-sized",
+  "version": "1.0.3",
+  "lockfileVersion": 1,
+  "requires": true,
+  "dependencies": {
+    "@babel/code-frame": {
+      "version": "7.5.5",
+      "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.5.5.tgz",
+      "integrity": "sha512-27d4lZoomVyo51VegxI20xZPuSHusqbQag/ztrBC7wegWoQ1nLREPVSKSW8byhTlzTKyNE4ifaTA6lCp7JjpFw==",
+      "dev": true,
+      "requires": {
+        "@babel/highlight": "^7.0.0"
+      }
+    },
+    "@babel/generator": {
+      "version": "7.6.0",
+      "resolved": "https://registry.npmjs.org/@babel/generator/-/generator-7.6.0.tgz",
+      "integrity": "sha512-Ms8Mo7YBdMMn1BYuNtKuP/z0TgEIhbcyB8HVR6PPNYp4P61lMsABiS4A3VG1qznjXVCf3r+fVHhm4efTYVsySA==",
+      "dev": true,
+      "requires": {
+        "@babel/types": "^7.6.0",
+        "jsesc": "^2.5.1",
+        "lodash": "^4.17.13",
+        "source-map": "^0.5.0",
+        "trim-right": "^1.0.1"
+      },
+      "dependencies": {
+        "source-map": {
+          "version": "0.5.7",
+          "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.5.7.tgz",
+          "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=",
+          "dev": true
+        }
+      }
+    },
+    "@babel/helper-function-name": {
+      "version": "7.1.0",
+      "resolved": "https://registry.npmjs.org/@babel/helper-function-name/-/helper-function-name-7.1.0.tgz",
+      "integrity": "sha512-A95XEoCpb3TO+KZzJ4S/5uW5fNe26DjBGqf1o9ucyLyCmi1dXq/B3c8iaWTfBk3VvetUxl16e8tIrd5teOCfGw==",
+      "dev": true,
+      "requires": {
+        "@babel/helper-get-function-arity": "^7.0.0",
+        "@babel/template": "^7.1.0",
+        "@babel/types": "^7.0.0"
+      }
+    },
+    "@babel/helper-get-function-arity": {
+      "version": "7.0.0",
+      "resolved": "https://registry.npmjs.org/@babel/helper-get-function-arity/-/helper-get-function-arity-7.0.0.tgz",
+      "integrity": "sha512-r2DbJeg4svYvt3HOS74U4eWKsUAMRH01Z1ds1zx8KNTPtpTL5JAsdFv8BNyOpVqdFhHkkRDIg5B4AsxmkjAlmQ==",
+      "dev": true,
+      "requires": {
+        "@babel/types": "^7.0.0"
+      }
+    },
+    "@babel/helper-split-export-declaration": {
+      "version": "7.4.4",
+      "resolved": "https://registry.npmjs.org/@babel/helper-split-export-declaration/-/helper-split-export-declaration-7.4.4.tgz",
+      "integrity": "sha512-Ro/XkzLf3JFITkW6b+hNxzZ1n5OQ80NvIUdmHspih1XAhtN3vPTuUFT4eQnela+2MaZ5ulH+iyP513KJrxbN7Q==",
+      "dev": true,
+      "requires": {
+        "@babel/types": "^7.4.4"
+      }
+    },
+    "@babel/highlight": {
+      "version": "7.5.0",
+      "resolved": "https://registry.npmjs.org/@babel/highlight/-/highlight-7.5.0.tgz",
+      "integrity": "sha512-7dV4eu9gBxoM0dAnj/BCFDW9LFU0zvTrkq0ugM7pnHEgguOEeOz1so2ZghEdzviYzQEED0r4EAgpsBChKy1TRQ==",
+      "dev": true,
+      "requires": {
+        "chalk": "^2.0.0",
+        "esutils": "^2.0.2",
+        "js-tokens": "^4.0.0"
+      }
+    },
+    "@babel/parser": {
+      "version": "7.6.0",
+      "resolved": "https://registry.npmjs.org/@babel/parser/-/parser-7.6.0.tgz",
+      "integrity": "sha512-+o2q111WEx4srBs7L9eJmcwi655eD8sXniLqMB93TBK9GrNzGrxDWSjiqz2hLU0Ha8MTXFIP0yd9fNdP+m43ZQ==",
+      "dev": true
+    },
+    "@babel/runtime": {
+      "version": "7.6.0",
+      "resolved": "https://registry.npmjs.org/@babel/runtime/-/runtime-7.6.0.tgz",
+      "integrity": "sha512-89eSBLJsxNxOERC0Op4vd+0Bqm6wRMqMbFtV3i0/fbaWw/mJ8Q3eBvgX0G4SyrOOLCtbu98HspF8o09MRT+KzQ==",
+      "dev": true,
+      "requires": {
+        "regenerator-runtime": "^0.13.2"
+      }
+    },
+    "@babel/template": {
+      "version": "7.6.0",
+      "resolved": "https://registry.npmjs.org/@babel/template/-/template-7.6.0.tgz",
+      "integrity": "sha512-5AEH2EXD8euCk446b7edmgFdub/qfH1SN6Nii3+fyXP807QRx9Q73A2N5hNwRRslC2H9sNzaFhsPubkS4L8oNQ==",
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+}
diff --git a/server/node_modules/minipass-sized/package.json b/server/node_modules/minipass-sized/package.json
new file mode 100644
index 0000000..a3257fd
--- /dev/null
+++ b/server/node_modules/minipass-sized/package.json
@@ -0,0 +1,39 @@
+{
+  "name": "minipass-sized",
+  "version": "1.0.3",
+  "description": "A Minipass stream that raises an error if you get a different number of bytes than expected",
+  "author": "Isaac Z. Schlueter <i@izs.me> (https://izs.me)",
+  "license": "ISC",
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "tap": {
+    "check-coverage": true
+  },
+  "devDependencies": {
+    "tap": "^14.6.4"
+  },
+  "dependencies": {
+    "minipass": "^3.0.0"
+  },
+  "main": "index.js",
+  "keywords": [
+    "minipass",
+    "size",
+    "length"
+  ],
+  "directories": {
+    "test": "test"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/isaacs/minipass-sized.git"
+  },
+  "engines": {
+    "node": ">=8"
+  }
+}
diff --git a/server/node_modules/minipass-sized/test/basic.js b/server/node_modules/minipass-sized/test/basic.js
new file mode 100644
index 0000000..bbdcada
--- /dev/null
+++ b/server/node_modules/minipass-sized/test/basic.js
@@ -0,0 +1,83 @@
+const t = require('tap')
+const MPS = require('../')
+
+t.test('ok if size checks out', t => {
+  const mps = new MPS({ size: 4 })
+
+  mps.write(Buffer.from('a').toString('hex'), 'hex')
+  mps.write(Buffer.from('sd'))
+  mps.end('f')
+  return mps.concat().then(data => t.equal(data.toString(), 'asdf'))
+})
+
+t.test('error if size exceeded', t => {
+  const mps = new MPS({ size: 1 })
+  mps.on('error', er => {
+    t.match(er, {
+      message: 'Bad data size: expected 1 bytes, but got 4',
+      found: 4,
+      expect: 1,
+      code: 'EBADSIZE',
+      name: 'SizeError',
+    })
+    t.end()
+  })
+  mps.write('asdf')
+})
+
+t.test('error if size is not met', t => {
+  const mps = new MPS({ size: 999 })
+  t.throws(() => mps.end(), {
+    message: 'Bad data size: expected 999 bytes, but got 0',
+    found: 0,
+    name: 'SizeError',
+    expect: 999,
+    code: 'EBADSIZE',
+  })
+  t.end()
+})
+
+t.test('error if non-string/buffer is written', t => {
+  const mps = new MPS({size:1})
+  mps.on('error', er => {
+    t.match(er, {
+      message: 'MinipassSized streams only work with string and buffer data'
+    })
+    t.end()
+  })
+  mps.write({some:'object'})
+})
+
+t.test('projectiles', t => {
+  t.throws(() => new MPS(), {
+    message: 'invalid expected size: undefined'
+  }, 'size is required')
+  t.throws(() => new MPS({size: true}), {
+    message: 'invalid expected size: true'
+  }, 'size must be number')
+  t.throws(() => new MPS({size: NaN}), {
+    message: 'invalid expected size: NaN'
+  }, 'size must not be NaN')
+  t.throws(() => new MPS({size:1.2}), {
+    message: 'invalid expected size: 1.2'
+  }, 'size must be integer')
+  t.throws(() => new MPS({size: Infinity}), {
+    message: 'invalid expected size: Infinity'
+  }, 'size must be finite')
+  t.throws(() => new MPS({size: -1}), {
+    message: 'invalid expected size: -1'
+  }, 'size must be positive')
+  t.throws(() => new MPS({objectMode: true}), {
+    message: 'MinipassSized streams only work with string and buffer data'
+  }, 'no objectMode')
+  t.throws(() => new MPS({size: Number.MAX_SAFE_INTEGER + 1000000}), {
+    message: 'invalid expected size: 9007199255740992'
+  })
+  t.end()
+})
+
+t.test('exports SizeError class', t => {
+  t.isa(MPS.SizeError, 'function')
+  t.isa(MPS.SizeError.prototype, Error)
+  t.end()
+})
diff --git a/server/node_modules/minipass/LICENSE b/server/node_modules/minipass/LICENSE
new file mode 100644
index 0000000..bf1dece
--- /dev/null
+++ b/server/node_modules/minipass/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) 2017-2022 npm, Inc., Isaac Z. Schlueter, and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/minipass/README.md b/server/node_modules/minipass/README.md
new file mode 100644
index 0000000..2cde46c
--- /dev/null
+++ b/server/node_modules/minipass/README.md
@@ -0,0 +1,728 @@
+# minipass
+
+A _very_ minimal implementation of a [PassThrough
+stream](https://nodejs.org/api/stream.html#stream_class_stream_passthrough)
+
+[It's very
+fast](https://docs.google.com/spreadsheets/d/1oObKSrVwLX_7Ut4Z6g3fZW-AX1j1-k6w-cDsrkaSbHM/edit#gid=0)
+for objects, strings, and buffers.
+
+Supports `pipe()`ing (including multi-`pipe()` and backpressure transmission),
+buffering data until either a `data` event handler or `pipe()` is added (so
+you don't lose the first chunk), and most other cases where PassThrough is
+a good idea.
+
+There is a `read()` method, but it's much more efficient to consume data
+from this stream via `'data'` events or by calling `pipe()` into some other
+stream.  Calling `read()` requires the buffer to be flattened in some
+cases, which requires copying memory.
+
+If you set `objectMode: true` in the options, then whatever is written will
+be emitted.  Otherwise, it'll do a minimal amount of Buffer copying to
+ensure proper Streams semantics when `read(n)` is called.
+
+`objectMode` can also be set by doing `stream.objectMode = true`, or by
+writing any non-string/non-buffer data.  `objectMode` cannot be set to
+false once it is set.
+
+This is not a `through` or `through2` stream.  It doesn't transform the
+data, it just passes it right through.  If you want to transform the data,
+extend the class, and override the `write()` method.  Once you're done
+transforming the data however you want, call `super.write()` with the
+transform output.
+
+For some examples of streams that extend Minipass in various ways, check
+out:
+
+- [minizlib](http://npm.im/minizlib)
+- [fs-minipass](http://npm.im/fs-minipass)
+- [tar](http://npm.im/tar)
+- [minipass-collect](http://npm.im/minipass-collect)
+- [minipass-flush](http://npm.im/minipass-flush)
+- [minipass-pipeline](http://npm.im/minipass-pipeline)
+- [tap](http://npm.im/tap)
+- [tap-parser](http://npm.im/tap-parser)
+- [treport](http://npm.im/treport)
+- [minipass-fetch](http://npm.im/minipass-fetch)
+- [pacote](http://npm.im/pacote)
+- [make-fetch-happen](http://npm.im/make-fetch-happen)
+- [cacache](http://npm.im/cacache)
+- [ssri](http://npm.im/ssri)
+- [npm-registry-fetch](http://npm.im/npm-registry-fetch)
+- [minipass-json-stream](http://npm.im/minipass-json-stream)
+- [minipass-sized](http://npm.im/minipass-sized)
+
+## Differences from Node.js Streams
+
+There are several things that make Minipass streams different from (and in
+some ways superior to) Node.js core streams.
+
+Please read these caveats if you are familiar with node-core streams and
+intend to use Minipass streams in your programs.
+
+You can avoid most of these differences entirely (for a very
+small performance penalty) by setting `{async: true}` in the
+constructor options.
+
+### Timing
+
+Minipass streams are designed to support synchronous use-cases.  Thus, data
+is emitted as soon as it is available, always.  It is buffered until read,
+but no longer.  Another way to look at it is that Minipass streams are
+exactly as synchronous as the logic that writes into them.
+
+This can be surprising if your code relies on `PassThrough.write()` always
+providing data on the next tick rather than the current one, or being able
+to call `resume()` and not have the entire buffer disappear immediately.
+
+However, without this synchronicity guarantee, there would be no way for
+Minipass to achieve the speeds it does, or support the synchronous use
+cases that it does.  Simply put, waiting takes time.
+
+This non-deferring approach makes Minipass streams much easier to reason
+about, especially in the context of Promises and other flow-control
+mechanisms.
+
+Example:
+
+```js
+const Minipass = require('minipass')
+const stream = new Minipass({ async: true })
+stream.on('data', () => console.log('data event'))
+console.log('before write')
+stream.write('hello')
+console.log('after write')
+// output:
+// before write
+// data event
+// after write
+```
+
+### Exception: Async Opt-In
+
+If you wish to have a Minipass stream with behavior that more
+closely mimics Node.js core streams, you can set the stream in
+async mode either by setting `async: true` in the constructor
+options, or by setting `stream.async = true` later on.
+
+```js
+const Minipass = require('minipass')
+const asyncStream = new Minipass({ async: true })
+asyncStream.on('data', () => console.log('data event'))
+console.log('before write')
+asyncStream.write('hello')
+console.log('after write')
+// output:
+// before write
+// after write
+// data event <-- this is deferred until the next tick
+```
+
+Switching _out_ of async mode is unsafe, as it could cause data
+corruption, and so is not enabled.  Example:
+
+```js
+const Minipass = require('minipass')
+const stream = new Minipass({ encoding: 'utf8' })
+stream.on('data', chunk => console.log(chunk))
+stream.async = true
+console.log('before writes')
+stream.write('hello')
+setStreamSyncAgainSomehow(stream) // <-- this doesn't actually exist!
+stream.write('world')
+console.log('after writes')
+// hypothetical output would be:
+// before writes
+// world
+// after writes
+// hello
+// NOT GOOD!
+```
+
+To avoid this problem, once set into async mode, any attempt to
+make the stream sync again will be ignored.
+
+```js
+const Minipass = require('minipass')
+const stream = new Minipass({ encoding: 'utf8' })
+stream.on('data', chunk => console.log(chunk))
+stream.async = true
+console.log('before writes')
+stream.write('hello')
+stream.async = false // <-- no-op, stream already async
+stream.write('world')
+console.log('after writes')
+// actual output:
+// before writes
+// after writes
+// hello
+// world
+```
+
+### No High/Low Water Marks
+
+Node.js core streams will optimistically fill up a buffer, returning `true`
+on all writes until the limit is hit, even if the data has nowhere to go.
+Then, they will not attempt to draw more data in until the buffer size dips
+below a minimum value.
+
+Minipass streams are much simpler.  The `write()` method will return `true`
+if the data has somewhere to go (which is to say, given the timing
+guarantees, that the data is already there by the time `write()` returns).
+
+If the data has nowhere to go, then `write()` returns false, and the data
+sits in a buffer, to be drained out immediately as soon as anyone consumes
+it.
+
+Since nothing is ever buffered unnecessarily, there is much less
+copying data, and less bookkeeping about buffer capacity levels.
+
+### Hazards of Buffering (or: Why Minipass Is So Fast)
+
+Since data written to a Minipass stream is immediately written all the way
+through the pipeline, and `write()` always returns true/false based on
+whether the data was fully flushed, backpressure is communicated
+immediately to the upstream caller.  This minimizes buffering.
+
+Consider this case:
+
+```js
+const {PassThrough} = require('stream')
+const p1 = new PassThrough({ highWaterMark: 1024 })
+const p2 = new PassThrough({ highWaterMark: 1024 })
+const p3 = new PassThrough({ highWaterMark: 1024 })
+const p4 = new PassThrough({ highWaterMark: 1024 })
+
+p1.pipe(p2).pipe(p3).pipe(p4)
+p4.on('data', () => console.log('made it through'))
+
+// this returns false and buffers, then writes to p2 on next tick (1)
+// p2 returns false and buffers, pausing p1, then writes to p3 on next tick (2)
+// p3 returns false and buffers, pausing p2, then writes to p4 on next tick (3)
+// p4 returns false and buffers, pausing p3, then emits 'data' and 'drain'
+// on next tick (4)
+// p3 sees p4's 'drain' event, and calls resume(), emitting 'resume' and
+// 'drain' on next tick (5)
+// p2 sees p3's 'drain', calls resume(), emits 'resume' and 'drain' on next tick (6)
+// p1 sees p2's 'drain', calls resume(), emits 'resume' and 'drain' on next
+// tick (7)
+
+p1.write(Buffer.alloc(2048)) // returns false
+```
+
+Along the way, the data was buffered and deferred at each stage, and
+multiple event deferrals happened, for an unblocked pipeline where it was
+perfectly safe to write all the way through!
+
+Furthermore, setting a `highWaterMark` of `1024` might lead someone reading
+the code to think an advisory maximum of 1KiB is being set for the
+pipeline.  However, the actual advisory buffering level is the _sum_ of
+`highWaterMark` values, since each one has its own bucket.
+
+Consider the Minipass case:
+
+```js
+const m1 = new Minipass()
+const m2 = new Minipass()
+const m3 = new Minipass()
+const m4 = new Minipass()
+
+m1.pipe(m2).pipe(m3).pipe(m4)
+m4.on('data', () => console.log('made it through'))
+
+// m1 is flowing, so it writes the data to m2 immediately
+// m2 is flowing, so it writes the data to m3 immediately
+// m3 is flowing, so it writes the data to m4 immediately
+// m4 is flowing, so it fires the 'data' event immediately, returns true
+// m4's write returned true, so m3 is still flowing, returns true
+// m3's write returned true, so m2 is still flowing, returns true
+// m2's write returned true, so m1 is still flowing, returns true
+// No event deferrals or buffering along the way!
+
+m1.write(Buffer.alloc(2048)) // returns true
+```
+
+It is extremely unlikely that you _don't_ want to buffer any data written,
+or _ever_ buffer data that can be flushed all the way through.  Neither
+node-core streams nor Minipass ever fail to buffer written data, but
+node-core streams do a lot of unnecessary buffering and pausing.
+
+As always, the faster implementation is the one that does less stuff and
+waits less time to do it.
+
+### Immediately emit `end` for empty streams (when not paused)
+
+If a stream is not paused, and `end()` is called before writing any data
+into it, then it will emit `end` immediately.
+
+If you have logic that occurs on the `end` event which you don't want to
+potentially happen immediately (for example, closing file descriptors,
+moving on to the next entry in an archive parse stream, etc.) then be sure
+to call `stream.pause()` on creation, and then `stream.resume()` once you
+are ready to respond to the `end` event.
+
+However, this is _usually_ not a problem because:
+
+### Emit `end` When Asked
+
+One hazard of immediately emitting `'end'` is that you may not yet have had
+a chance to add a listener.  In order to avoid this hazard, Minipass
+streams safely re-emit the `'end'` event if a new listener is added after
+`'end'` has been emitted.
+
+Ie, if you do `stream.on('end', someFunction)`, and the stream has already
+emitted `end`, then it will call the handler right away.  (You can think of
+this somewhat like attaching a new `.then(fn)` to a previously-resolved
+Promise.)
+
+To prevent calling handlers multiple times who would not expect multiple
+ends to occur, all listeners are removed from the `'end'` event whenever it
+is emitted.
+
+### Emit `error` When Asked
+
+The most recent error object passed to the `'error'` event is
+stored on the stream.  If a new `'error'` event handler is added,
+and an error was previously emitted, then the event handler will
+be called immediately (or on `process.nextTick` in the case of
+async streams).
+
+This makes it much more difficult to end up trying to interact
+with a broken stream, if the error handler is added after an
+error was previously emitted.
+
+### Impact of "immediate flow" on Tee-streams
+
+A "tee stream" is a stream piping to multiple destinations:
+
+```js
+const tee = new Minipass()
+t.pipe(dest1)
+t.pipe(dest2)
+t.write('foo') // goes to both destinations
+```
+
+Since Minipass streams _immediately_ process any pending data through the
+pipeline when a new pipe destination is added, this can have surprising
+effects, especially when a stream comes in from some other function and may
+or may not have data in its buffer.
+
+```js
+// WARNING! WILL LOSE DATA!
+const src = new Minipass()
+src.write('foo')
+src.pipe(dest1) // 'foo' chunk flows to dest1 immediately, and is gone
+src.pipe(dest2) // gets nothing!
+```
+
+One solution is to create a dedicated tee-stream junction that pipes to
+both locations, and then pipe to _that_ instead.
+
+```js
+// Safe example: tee to both places
+const src = new Minipass()
+src.write('foo')
+const tee = new Minipass()
+tee.pipe(dest1)
+tee.pipe(dest2)
+src.pipe(tee) // tee gets 'foo', pipes to both locations
+```
+
+The same caveat applies to `on('data')` event listeners.  The first one
+added will _immediately_ receive all of the data, leaving nothing for the
+second:
+
+```js
+// WARNING! WILL LOSE DATA!
+const src = new Minipass()
+src.write('foo')
+src.on('data', handler1) // receives 'foo' right away
+src.on('data', handler2) // nothing to see here!
+```
+
+Using a dedicated tee-stream can be used in this case as well:
+
+```js
+// Safe example: tee to both data handlers
+const src = new Minipass()
+src.write('foo')
+const tee = new Minipass()
+tee.on('data', handler1)
+tee.on('data', handler2)
+src.pipe(tee)
+```
+
+All of the hazards in this section are avoided by setting `{
+async: true }` in the Minipass constructor, or by setting
+`stream.async = true` afterwards.  Note that this does add some
+overhead, so should only be done in cases where you are willing
+to lose a bit of performance in order to avoid having to refactor
+program logic.
+
+## USAGE
+
+It's a stream!  Use it like a stream and it'll most likely do what you
+want.
+
+```js
+const Minipass = require('minipass')
+const mp = new Minipass(options) // optional: { encoding, objectMode }
+mp.write('foo')
+mp.pipe(someOtherStream)
+mp.end('bar')
+```
+
+### OPTIONS
+
+* `encoding` How would you like the data coming _out_ of the stream to be
+  encoded?  Accepts any values that can be passed to `Buffer.toString()`.
+* `objectMode` Emit data exactly as it comes in.  This will be flipped on
+  by default if you write() something other than a string or Buffer at any
+  point.  Setting `objectMode: true` will prevent setting any encoding
+  value.
+* `async` Defaults to `false`.  Set to `true` to defer data
+  emission until next tick.  This reduces performance slightly,
+  but makes Minipass streams use timing behavior closer to Node
+  core streams.  See [Timing](#timing) for more details.
+
+### API
+
+Implements the user-facing portions of Node.js's `Readable` and `Writable`
+streams.
+
+### Methods
+
+* `write(chunk, [encoding], [callback])` - Put data in.  (Note that, in the
+  base Minipass class, the same data will come out.)  Returns `false` if
+  the stream will buffer the next write, or true if it's still in "flowing"
+  mode.
+* `end([chunk, [encoding]], [callback])` - Signal that you have no more
+  data to write.  This will queue an `end` event to be fired when all the
+  data has been consumed.
+* `setEncoding(encoding)` - Set the encoding for data coming of the stream.
+  This can only be done once.
+* `pause()` - No more data for a while, please.  This also prevents `end`
+  from being emitted for empty streams until the stream is resumed.
+* `resume()` - Resume the stream.  If there's data in the buffer, it is all
+  discarded.  Any buffered events are immediately emitted.
+* `pipe(dest)` - Send all output to the stream provided.  When
+  data is emitted, it is immediately written to any and all pipe
+  destinations.  (Or written on next tick in `async` mode.)
+* `unpipe(dest)` - Stop piping to the destination stream.  This
+  is immediate, meaning that any asynchronously queued data will
+  _not_ make it to the destination when running in `async` mode.
+    * `options.end` - Boolean, end the destination stream when
+      the source stream ends.  Default `true`.
+    * `options.proxyErrors` - Boolean, proxy `error` events from
+      the source stream to the destination stream.  Note that
+      errors are _not_ proxied after the pipeline terminates,
+      either due to the source emitting `'end'` or manually
+      unpiping with `src.unpipe(dest)`.  Default `false`.
+* `on(ev, fn)`, `emit(ev, fn)` - Minipass streams are EventEmitters.  Some
+  events are given special treatment, however.  (See below under "events".)
+* `promise()` - Returns a Promise that resolves when the stream emits
+  `end`, or rejects if the stream emits `error`.
+* `collect()` - Return a Promise that resolves on `end` with an array
+  containing each chunk of data that was emitted, or rejects if the stream
+  emits `error`.  Note that this consumes the stream data.
+* `concat()` - Same as `collect()`, but concatenates the data into a single
+  Buffer object.  Will reject the returned promise if the stream is in
+  objectMode, or if it goes into objectMode by the end of the data.
+* `read(n)` - Consume `n` bytes of data out of the buffer.  If `n` is not
+  provided, then consume all of it.  If `n` bytes are not available, then
+  it returns null.  **Note** consuming streams in this way is less
+  efficient, and can lead to unnecessary Buffer copying.
+* `destroy([er])` - Destroy the stream.  If an error is provided, then an
+  `'error'` event is emitted.  If the stream has a `close()` method, and
+  has not emitted a `'close'` event yet, then `stream.close()` will be
+  called.  Any Promises returned by `.promise()`, `.collect()` or
+  `.concat()` will be rejected.  After being destroyed, writing to the
+  stream will emit an error.  No more data will be emitted if the stream is
+  destroyed, even if it was previously buffered.
+
+### Properties
+
+* `bufferLength` Read-only.  Total number of bytes buffered, or in the case
+  of objectMode, the total number of objects.
+* `encoding` The encoding that has been set.  (Setting this is equivalent
+  to calling `setEncoding(enc)` and has the same prohibition against
+  setting multiple times.)
+* `flowing` Read-only.  Boolean indicating whether a chunk written to the
+  stream will be immediately emitted.
+* `emittedEnd` Read-only.  Boolean indicating whether the end-ish events
+  (ie, `end`, `prefinish`, `finish`) have been emitted.  Note that
+  listening on any end-ish event will immediateyl re-emit it if it has
+  already been emitted.
+* `writable` Whether the stream is writable.  Default `true`.  Set to
+  `false` when `end()`
+* `readable` Whether the stream is readable.  Default `true`.
+* `buffer` A [yallist](http://npm.im/yallist) linked list of chunks written
+  to the stream that have not yet been emitted.  (It's probably a bad idea
+  to mess with this.)
+* `pipes` A [yallist](http://npm.im/yallist) linked list of streams that
+  this stream is piping into.  (It's probably a bad idea to mess with
+  this.)
+* `destroyed` A getter that indicates whether the stream was destroyed.
+* `paused` True if the stream has been explicitly paused, otherwise false.
+* `objectMode` Indicates whether the stream is in `objectMode`.  Once set
+  to `true`, it cannot be set to `false`.
+
+### Events
+
+* `data` Emitted when there's data to read.  Argument is the data to read.
+  This is never emitted while not flowing.  If a listener is attached, that
+  will resume the stream.
+* `end` Emitted when there's no more data to read.  This will be emitted
+  immediately for empty streams when `end()` is called.  If a listener is
+  attached, and `end` was already emitted, then it will be emitted again.
+  All listeners are removed when `end` is emitted.
+* `prefinish` An end-ish event that follows the same logic as `end` and is
+  emitted in the same conditions where `end` is emitted.  Emitted after
+  `'end'`.
+* `finish` An end-ish event that follows the same logic as `end` and is
+  emitted in the same conditions where `end` is emitted.  Emitted after
+  `'prefinish'`.
+* `close` An indication that an underlying resource has been released.
+  Minipass does not emit this event, but will defer it until after `end`
+  has been emitted, since it throws off some stream libraries otherwise.
+* `drain` Emitted when the internal buffer empties, and it is again
+  suitable to `write()` into the stream.
+* `readable` Emitted when data is buffered and ready to be read by a
+  consumer.
+* `resume` Emitted when stream changes state from buffering to flowing
+  mode.  (Ie, when `resume` is called, `pipe` is called, or a `data` event
+  listener is added.)
+
+### Static Methods
+
+* `Minipass.isStream(stream)` Returns `true` if the argument is a stream,
+  and false otherwise.  To be considered a stream, the object must be
+  either an instance of Minipass, or an EventEmitter that has either a
+  `pipe()` method, or both `write()` and `end()` methods.  (Pretty much any
+  stream in node-land will return `true` for this.)
+
+## EXAMPLES
+
+Here are some examples of things you can do with Minipass streams.
+
+### simple "are you done yet" promise
+
+```js
+mp.promise().then(() => {
+  // stream is finished
+}, er => {
+  // stream emitted an error
+})
+```
+
+### collecting
+
+```js
+mp.collect().then(all => {
+  // all is an array of all the data emitted
+  // encoding is supported in this case, so
+  // so the result will be a collection of strings if
+  // an encoding is specified, or buffers/objects if not.
+  //
+  // In an async function, you may do
+  // const data = await stream.collect()
+})
+```
+
+### collecting into a single blob
+
+This is a bit slower because it concatenates the data into one chunk for
+you, but if you're going to do it yourself anyway, it's convenient this
+way:
+
+```js
+mp.concat().then(onebigchunk => {
+  // onebigchunk is a string if the stream
+  // had an encoding set, or a buffer otherwise.
+})
+```
+
+### iteration
+
+You can iterate over streams synchronously or asynchronously in platforms
+that support it.
+
+Synchronous iteration will end when the currently available data is
+consumed, even if the `end` event has not been reached.  In string and
+buffer mode, the data is concatenated, so unless multiple writes are
+occurring in the same tick as the `read()`, sync iteration loops will
+generally only have a single iteration.
+
+To consume chunks in this way exactly as they have been written, with no
+flattening, create the stream with the `{ objectMode: true }` option.
+
+```js
+const mp = new Minipass({ objectMode: true })
+mp.write('a')
+mp.write('b')
+for (let letter of mp) {
+  console.log(letter) // a, b
+}
+mp.write('c')
+mp.write('d')
+for (let letter of mp) {
+  console.log(letter) // c, d
+}
+mp.write('e')
+mp.end()
+for (let letter of mp) {
+  console.log(letter) // e
+}
+for (let letter of mp) {
+  console.log(letter) // nothing
+}
+```
+
+Asynchronous iteration will continue until the end event is reached,
+consuming all of the data.
+
+```js
+const mp = new Minipass({ encoding: 'utf8' })
+
+// some source of some data
+let i = 5
+const inter = setInterval(() => {
+  if (i-- > 0)
+    mp.write(Buffer.from('foo\n', 'utf8'))
+  else {
+    mp.end()
+    clearInterval(inter)
+  }
+}, 100)
+
+// consume the data with asynchronous iteration
+async function consume () {
+  for await (let chunk of mp) {
+    console.log(chunk)
+  }
+  return 'ok'
+}
+
+consume().then(res => console.log(res))
+// logs `foo\n` 5 times, and then `ok`
+```
+
+### subclass that `console.log()`s everything written into it
+
+```js
+class Logger extends Minipass {
+  write (chunk, encoding, callback) {
+    console.log('WRITE', chunk, encoding)
+    return super.write(chunk, encoding, callback)
+  }
+  end (chunk, encoding, callback) {
+    console.log('END', chunk, encoding)
+    return super.end(chunk, encoding, callback)
+  }
+}
+
+someSource.pipe(new Logger()).pipe(someDest)
+```
+
+### same thing, but using an inline anonymous class
+
+```js
+// js classes are fun
+someSource
+  .pipe(new (class extends Minipass {
+    emit (ev, ...data) {
+      // let's also log events, because debugging some weird thing
+      console.log('EMIT', ev)
+      return super.emit(ev, ...data)
+    }
+    write (chunk, encoding, callback) {
+      console.log('WRITE', chunk, encoding)
+      return super.write(chunk, encoding, callback)
+    }
+    end (chunk, encoding, callback) {
+      console.log('END', chunk, encoding)
+      return super.end(chunk, encoding, callback)
+    }
+  }))
+  .pipe(someDest)
+```
+
+### subclass that defers 'end' for some reason
+
+```js
+class SlowEnd extends Minipass {
+  emit (ev, ...args) {
+    if (ev === 'end') {
+      console.log('going to end, hold on a sec')
+      setTimeout(() => {
+        console.log('ok, ready to end now')
+        super.emit('end', ...args)
+      }, 100)
+    } else {
+      return super.emit(ev, ...args)
+    }
+  }
+}
+```
+
+### transform that creates newline-delimited JSON
+
+```js
+class NDJSONEncode extends Minipass {
+  write (obj, cb) {
+    try {
+      // JSON.stringify can throw, emit an error on that
+      return super.write(JSON.stringify(obj) + '\n', 'utf8', cb)
+    } catch (er) {
+      this.emit('error', er)
+    }
+  }
+  end (obj, cb) {
+    if (typeof obj === 'function') {
+      cb = obj
+      obj = undefined
+    }
+    if (obj !== undefined) {
+      this.write(obj)
+    }
+    return super.end(cb)
+  }
+}
+```
+
+### transform that parses newline-delimited JSON
+
+```js
+class NDJSONDecode extends Minipass {
+  constructor (options) {
+    // always be in object mode, as far as Minipass is concerned
+    super({ objectMode: true })
+    this._jsonBuffer = ''
+  }
+  write (chunk, encoding, cb) {
+    if (typeof chunk === 'string' &&
+        typeof encoding === 'string' &&
+        encoding !== 'utf8') {
+      chunk = Buffer.from(chunk, encoding).toString()
+    } else if (Buffer.isBuffer(chunk))
+      chunk = chunk.toString()
+    }
+    if (typeof encoding === 'function') {
+      cb = encoding
+    }
+    const jsonData = (this._jsonBuffer + chunk).split('\n')
+    this._jsonBuffer = jsonData.pop()
+    for (let i = 0; i < jsonData.length; i++) {
+      try {
+        // JSON.parse can throw, emit an error on that
+        super.write(JSON.parse(jsonData[i]))
+      } catch (er) {
+        this.emit('error', er)
+        continue
+      }
+    }
+    if (cb)
+      cb()
+  }
+}
+```
diff --git a/server/node_modules/minipass/index.d.ts b/server/node_modules/minipass/index.d.ts
new file mode 100644
index 0000000..65faf63
--- /dev/null
+++ b/server/node_modules/minipass/index.d.ts
@@ -0,0 +1,155 @@
+/// <reference types="node" />
+import { EventEmitter } from 'events'
+import { Stream } from 'stream'
+
+declare namespace Minipass {
+  type Encoding = BufferEncoding | 'buffer' | null
+
+  interface Writable extends EventEmitter {
+    end(): any
+    write(chunk: any, ...args: any[]): any
+  }
+
+  interface Readable extends EventEmitter {
+    pause(): any
+    resume(): any
+    pipe(): any
+  }
+
+  interface Pipe<R, W> {
+    src: Minipass<R, W>
+    dest: Writable
+    opts: PipeOptions
+  }
+
+  type DualIterable<T> = Iterable<T> & AsyncIterable<T>
+
+  type ContiguousData = Buffer | ArrayBufferLike | ArrayBufferView | string
+
+  type BufferOrString = Buffer | string
+
+  interface StringOptions {
+    encoding: BufferEncoding
+    objectMode?: boolean
+    async?: boolean
+  }
+
+  interface BufferOptions {
+    encoding?: null | 'buffer'
+    objectMode?: boolean
+    async?: boolean
+  }
+
+  interface ObjectModeOptions {
+    objectMode: true
+    async?: boolean
+  }
+
+  interface PipeOptions {
+    end?: boolean
+    proxyErrors?: boolean
+  }
+
+  type Options<T> = T extends string
+    ? StringOptions
+    : T extends Buffer
+    ? BufferOptions
+    : ObjectModeOptions
+}
+
+declare class Minipass<
+    RType extends any = Buffer,
+    WType extends any = RType extends Minipass.BufferOrString
+      ? Minipass.ContiguousData
+      : RType
+  >
+  extends Stream
+  implements Minipass.DualIterable<RType>
+{
+  static isStream(stream: any): stream is Minipass.Readable | Minipass.Writable
+
+  readonly bufferLength: number
+  readonly flowing: boolean
+  readonly writable: boolean
+  readonly readable: boolean
+  readonly paused: boolean
+  readonly emittedEnd: boolean
+  readonly destroyed: boolean
+
+  /**
+   * Not technically private or readonly, but not safe to mutate.
+   */
+  private readonly buffer: RType[]
+  private readonly pipes: Minipass.Pipe<RType, WType>[]
+
+  /**
+   * Technically writable, but mutating it can change the type,
+   * so is not safe to do in TypeScript.
+   */
+  readonly objectMode: boolean
+  async: boolean
+
+  /**
+   * Note: encoding is not actually read-only, and setEncoding(enc)
+   * exists. However, this type definition will insist that TypeScript
+   * programs declare the type of a Minipass stream up front, and if
+   * that type is string, then an encoding MUST be set in the ctor. If
+   * the type is Buffer, then the encoding must be missing, or set to
+   * 'buffer' or null. If the type is anything else, then objectMode
+   * must be set in the constructor options.  So there is effectively
+   * no allowed way that a TS program can set the encoding after
+   * construction, as doing so will destroy any hope of type safety.
+   * TypeScript does not provide many options for changing the type of
+   * an object at run-time, which is what changing the encoding does.
+   */
+  readonly encoding: Minipass.Encoding
+  // setEncoding(encoding: Encoding): void
+
+  // Options required if not reading buffers
+  constructor(
+    ...args: RType extends Buffer
+      ? [] | [Minipass.Options<RType>]
+      : [Minipass.Options<RType>]
+  )
+
+  write(chunk: WType, cb?: () => void): boolean
+  write(chunk: WType, encoding?: Minipass.Encoding, cb?: () => void): boolean
+  read(size?: number): RType
+  end(cb?: () => void): this
+  end(chunk: any, cb?: () => void): this
+  end(chunk: any, encoding?: Minipass.Encoding, cb?: () => void): this
+  pause(): void
+  resume(): void
+  promise(): Promise<void>
+  collect(): Promise<RType[]>
+
+  concat(): RType extends Minipass.BufferOrString ? Promise<RType> : never
+  destroy(er?: any): void
+  pipe<W extends Minipass.Writable>(dest: W, opts?: Minipass.PipeOptions): W
+  unpipe<W extends Minipass.Writable>(dest: W): void
+
+  /**
+   * alias for on()
+   */
+  addEventHandler(event: string, listener: (...args: any[]) => any): this
+
+  on(event: string, listener: (...args: any[]) => any): this
+  on(event: 'data', listener: (chunk: RType) => any): this
+  on(event: 'error', listener: (error: any) => any): this
+  on(
+    event:
+      | 'readable'
+      | 'drain'
+      | 'resume'
+      | 'end'
+      | 'prefinish'
+      | 'finish'
+      | 'close',
+    listener: () => any
+  ): this
+
+  [Symbol.iterator](): Iterator<RType>
+  [Symbol.asyncIterator](): AsyncIterator<RType>
+}
+
+export = Minipass
diff --git a/server/node_modules/minipass/index.js b/server/node_modules/minipass/index.js
new file mode 100644
index 0000000..e8797aa
--- /dev/null
+++ b/server/node_modules/minipass/index.js
@@ -0,0 +1,649 @@
+'use strict'
+const proc = typeof process === 'object' && process ? process : {
+  stdout: null,
+  stderr: null,
+}
+const EE = require('events')
+const Stream = require('stream')
+const SD = require('string_decoder').StringDecoder
+
+const EOF = Symbol('EOF')
+const MAYBE_EMIT_END = Symbol('maybeEmitEnd')
+const EMITTED_END = Symbol('emittedEnd')
+const EMITTING_END = Symbol('emittingEnd')
+const EMITTED_ERROR = Symbol('emittedError')
+const CLOSED = Symbol('closed')
+const READ = Symbol('read')
+const FLUSH = Symbol('flush')
+const FLUSHCHUNK = Symbol('flushChunk')
+const ENCODING = Symbol('encoding')
+const DECODER = Symbol('decoder')
+const FLOWING = Symbol('flowing')
+const PAUSED = Symbol('paused')
+const RESUME = Symbol('resume')
+const BUFFERLENGTH = Symbol('bufferLength')
+const BUFFERPUSH = Symbol('bufferPush')
+const BUFFERSHIFT = Symbol('bufferShift')
+const OBJECTMODE = Symbol('objectMode')
+const DESTROYED = Symbol('destroyed')
+const EMITDATA = Symbol('emitData')
+const EMITEND = Symbol('emitEnd')
+const EMITEND2 = Symbol('emitEnd2')
+const ASYNC = Symbol('async')
+
+const defer = fn => Promise.resolve().then(fn)
+
+// TODO remove when Node v8 support drops
+const doIter = global._MP_NO_ITERATOR_SYMBOLS_  !== '1'
+const ASYNCITERATOR = doIter && Symbol.asyncIterator
+  || Symbol('asyncIterator not implemented')
+const ITERATOR = doIter && Symbol.iterator
+  || Symbol('iterator not implemented')
+
+// events that mean 'the stream is over'
+// these are treated specially, and re-emitted
+// if they are listened for after emitting.
+const isEndish = ev =>
+  ev === 'end' ||
+  ev === 'finish' ||
+  ev === 'prefinish'
+
+const isArrayBuffer = b => b instanceof ArrayBuffer ||
+  typeof b === 'object' &&
+  b.constructor &&
+  b.constructor.name === 'ArrayBuffer' &&
+  b.byteLength >= 0
+
+const isArrayBufferView = b => !Buffer.isBuffer(b) && ArrayBuffer.isView(b)
+
+class Pipe {
+  constructor (src, dest, opts) {
+    this.src = src
+    this.dest = dest
+    this.opts = opts
+    this.ondrain = () => src[RESUME]()
+    dest.on('drain', this.ondrain)
+  }
+  unpipe () {
+    this.dest.removeListener('drain', this.ondrain)
+  }
+  // istanbul ignore next - only here for the prototype
+  proxyErrors () {}
+  end () {
+    this.unpipe()
+    if (this.opts.end)
+      this.dest.end()
+  }
+}
+
+class PipeProxyErrors extends Pipe {
+  unpipe () {
+    this.src.removeListener('error', this.proxyErrors)
+    super.unpipe()
+  }
+  constructor (src, dest, opts) {
+    super(src, dest, opts)
+    this.proxyErrors = er => dest.emit('error', er)
+    src.on('error', this.proxyErrors)
+  }
+}
+
+module.exports = class Minipass extends Stream {
+  constructor (options) {
+    super()
+    this[FLOWING] = false
+    // whether we're explicitly paused
+    this[PAUSED] = false
+    this.pipes = []
+    this.buffer = []
+    this[OBJECTMODE] = options && options.objectMode || false
+    if (this[OBJECTMODE])
+      this[ENCODING] = null
+    else
+      this[ENCODING] = options && options.encoding || null
+    if (this[ENCODING] === 'buffer')
+      this[ENCODING] = null
+    this[ASYNC] = options && !!options.async || false
+    this[DECODER] = this[ENCODING] ? new SD(this[ENCODING]) : null
+    this[EOF] = false
+    this[EMITTED_END] = false
+    this[EMITTING_END] = false
+    this[CLOSED] = false
+    this[EMITTED_ERROR] = null
+    this.writable = true
+    this.readable = true
+    this[BUFFERLENGTH] = 0
+    this[DESTROYED] = false
+  }
+
+  get bufferLength () { return this[BUFFERLENGTH] }
+
+  get encoding () { return this[ENCODING] }
+  set encoding (enc) {
+    if (this[OBJECTMODE])
+      throw new Error('cannot set encoding in objectMode')
+
+    if (this[ENCODING] && enc !== this[ENCODING] &&
+        (this[DECODER] && this[DECODER].lastNeed || this[BUFFERLENGTH]))
+      throw new Error('cannot change encoding')
+
+    if (this[ENCODING] !== enc) {
+      this[DECODER] = enc ? new SD(enc) : null
+      if (this.buffer.length)
+        this.buffer = this.buffer.map(chunk => this[DECODER].write(chunk))
+    }
+
+    this[ENCODING] = enc
+  }
+
+  setEncoding (enc) {
+    this.encoding = enc
+  }
+
+  get objectMode () { return this[OBJECTMODE] }
+  set objectMode (om) { this[OBJECTMODE] = this[OBJECTMODE] || !!om }
+
+  get ['async'] () { return this[ASYNC] }
+  set ['async'] (a) { this[ASYNC] = this[ASYNC] || !!a }
+
+  write (chunk, encoding, cb) {
+    if (this[EOF])
+      throw new Error('write after end')
+
+    if (this[DESTROYED]) {
+      this.emit('error', Object.assign(
+        new Error('Cannot call write after a stream was destroyed'),
+        { code: 'ERR_STREAM_DESTROYED' }
+      ))
+      return true
+    }
+
+    if (typeof encoding === 'function')
+      cb = encoding, encoding = 'utf8'
+
+    if (!encoding)
+      encoding = 'utf8'
+
+    const fn = this[ASYNC] ? defer : f => f()
+
+    // convert array buffers and typed array views into buffers
+    // at some point in the future, we may want to do the opposite!
+    // leave strings and buffers as-is
+    // anything else switches us into object mode
+    if (!this[OBJECTMODE] && !Buffer.isBuffer(chunk)) {
+      if (isArrayBufferView(chunk))
+        chunk = Buffer.from(chunk.buffer, chunk.byteOffset, chunk.byteLength)
+      else if (isArrayBuffer(chunk))
+        chunk = Buffer.from(chunk)
+      else if (typeof chunk !== 'string')
+        // use the setter so we throw if we have encoding set
+        this.objectMode = true
+    }
+
+    // handle object mode up front, since it's simpler
+    // this yields better performance, fewer checks later.
+    if (this[OBJECTMODE]) {
+      /* istanbul ignore if - maybe impossible? */
+      if (this.flowing && this[BUFFERLENGTH] !== 0)
+        this[FLUSH](true)
+
+      if (this.flowing)
+        this.emit('data', chunk)
+      else
+        this[BUFFERPUSH](chunk)
+
+      if (this[BUFFERLENGTH] !== 0)
+        this.emit('readable')
+
+      if (cb)
+        fn(cb)
+
+      return this.flowing
+    }
+
+    // at this point the chunk is a buffer or string
+    // don't buffer it up or send it to the decoder
+    if (!chunk.length) {
+      if (this[BUFFERLENGTH] !== 0)
+        this.emit('readable')
+      if (cb)
+        fn(cb)
+      return this.flowing
+    }
+
+    // fast-path writing strings of same encoding to a stream with
+    // an empty buffer, skipping the buffer/decoder dance
+    if (typeof chunk === 'string' &&
+        // unless it is a string already ready for us to use
+        !(encoding === this[ENCODING] && !this[DECODER].lastNeed)) {
+      chunk = Buffer.from(chunk, encoding)
+    }
+
+    if (Buffer.isBuffer(chunk) && this[ENCODING])
+      chunk = this[DECODER].write(chunk)
+
+    // Note: flushing CAN potentially switch us into not-flowing mode
+    if (this.flowing && this[BUFFERLENGTH] !== 0)
+      this[FLUSH](true)
+
+    if (this.flowing)
+      this.emit('data', chunk)
+    else
+      this[BUFFERPUSH](chunk)
+
+    if (this[BUFFERLENGTH] !== 0)
+      this.emit('readable')
+
+    if (cb)
+      fn(cb)
+
+    return this.flowing
+  }
+
+  read (n) {
+    if (this[DESTROYED])
+      return null
+
+    if (this[BUFFERLENGTH] === 0 || n === 0 || n > this[BUFFERLENGTH]) {
+      this[MAYBE_EMIT_END]()
+      return null
+    }
+
+    if (this[OBJECTMODE])
+      n = null
+
+    if (this.buffer.length > 1 && !this[OBJECTMODE]) {
+      if (this.encoding)
+        this.buffer = [this.buffer.join('')]
+      else
+        this.buffer = [Buffer.concat(this.buffer, this[BUFFERLENGTH])]
+    }
+
+    const ret = this[READ](n || null, this.buffer[0])
+    this[MAYBE_EMIT_END]()
+    return ret
+  }
+
+  [READ] (n, chunk) {
+    if (n === chunk.length || n === null)
+      this[BUFFERSHIFT]()
+    else {
+      this.buffer[0] = chunk.slice(n)
+      chunk = chunk.slice(0, n)
+      this[BUFFERLENGTH] -= n
+    }
+
+    this.emit('data', chunk)
+
+    if (!this.buffer.length && !this[EOF])
+      this.emit('drain')
+
+    return chunk
+  }
+
+  end (chunk, encoding, cb) {
+    if (typeof chunk === 'function')
+      cb = chunk, chunk = null
+    if (typeof encoding === 'function')
+      cb = encoding, encoding = 'utf8'
+    if (chunk)
+      this.write(chunk, encoding)
+    if (cb)
+      this.once('end', cb)
+    this[EOF] = true
+    this.writable = false
+
+    // if we haven't written anything, then go ahead and emit,
+    // even if we're not reading.
+    // we'll re-emit if a new 'end' listener is added anyway.
+    // This makes MP more suitable to write-only use cases.
+    if (this.flowing || !this[PAUSED])
+      this[MAYBE_EMIT_END]()
+    return this
+  }
+
+  // don't let the internal resume be overwritten
+  [RESUME] () {
+    if (this[DESTROYED])
+      return
+
+    this[PAUSED] = false
+    this[FLOWING] = true
+    this.emit('resume')
+    if (this.buffer.length)
+      this[FLUSH]()
+    else if (this[EOF])
+      this[MAYBE_EMIT_END]()
+    else
+      this.emit('drain')
+  }
+
+  resume () {
+    return this[RESUME]()
+  }
+
+  pause () {
+    this[FLOWING] = false
+    this[PAUSED] = true
+  }
+
+  get destroyed () {
+    return this[DESTROYED]
+  }
+
+  get flowing () {
+    return this[FLOWING]
+  }
+
+  get paused () {
+    return this[PAUSED]
+  }
+
+  [BUFFERPUSH] (chunk) {
+    if (this[OBJECTMODE])
+      this[BUFFERLENGTH] += 1
+    else
+      this[BUFFERLENGTH] += chunk.length
+    this.buffer.push(chunk)
+  }
+
+  [BUFFERSHIFT] () {
+    if (this.buffer.length) {
+      if (this[OBJECTMODE])
+        this[BUFFERLENGTH] -= 1
+      else
+        this[BUFFERLENGTH] -= this.buffer[0].length
+    }
+    return this.buffer.shift()
+  }
+
+  [FLUSH] (noDrain) {
+    do {} while (this[FLUSHCHUNK](this[BUFFERSHIFT]()))
+
+    if (!noDrain && !this.buffer.length && !this[EOF])
+      this.emit('drain')
+  }
+
+  [FLUSHCHUNK] (chunk) {
+    return chunk ? (this.emit('data', chunk), this.flowing) : false
+  }
+
+  pipe (dest, opts) {
+    if (this[DESTROYED])
+      return
+
+    const ended = this[EMITTED_END]
+    opts = opts || {}
+    if (dest === proc.stdout || dest === proc.stderr)
+      opts.end = false
+    else
+      opts.end = opts.end !== false
+    opts.proxyErrors = !!opts.proxyErrors
+
+    // piping an ended stream ends immediately
+    if (ended) {
+      if (opts.end)
+        dest.end()
+    } else {
+      this.pipes.push(!opts.proxyErrors ? new Pipe(this, dest, opts)
+        : new PipeProxyErrors(this, dest, opts))
+      if (this[ASYNC])
+        defer(() => this[RESUME]())
+      else
+        this[RESUME]()
+    }
+
+    return dest
+  }
+
+  unpipe (dest) {
+    const p = this.pipes.find(p => p.dest === dest)
+    if (p) {
+      this.pipes.splice(this.pipes.indexOf(p), 1)
+      p.unpipe()
+    }
+  }
+
+  addListener (ev, fn) {
+    return this.on(ev, fn)
+  }
+
+  on (ev, fn) {
+    const ret = super.on(ev, fn)
+    if (ev === 'data' && !this.pipes.length && !this.flowing)
+      this[RESUME]()
+    else if (ev === 'readable' && this[BUFFERLENGTH] !== 0)
+      super.emit('readable')
+    else if (isEndish(ev) && this[EMITTED_END]) {
+      super.emit(ev)
+      this.removeAllListeners(ev)
+    } else if (ev === 'error' && this[EMITTED_ERROR]) {
+      if (this[ASYNC])
+        defer(() => fn.call(this, this[EMITTED_ERROR]))
+      else
+        fn.call(this, this[EMITTED_ERROR])
+    }
+    return ret
+  }
+
+  get emittedEnd () {
+    return this[EMITTED_END]
+  }
+
+  [MAYBE_EMIT_END] () {
+    if (!this[EMITTING_END] &&
+        !this[EMITTED_END] &&
+        !this[DESTROYED] &&
+        this.buffer.length === 0 &&
+        this[EOF]) {
+      this[EMITTING_END] = true
+      this.emit('end')
+      this.emit('prefinish')
+      this.emit('finish')
+      if (this[CLOSED])
+        this.emit('close')
+      this[EMITTING_END] = false
+    }
+  }
+
+  emit (ev, data, ...extra) {
+    // error and close are only events allowed after calling destroy()
+    if (ev !== 'error' && ev !== 'close' && ev !== DESTROYED && this[DESTROYED])
+      return
+    else if (ev === 'data') {
+      return !data ? false
+        : this[ASYNC] ? defer(() => this[EMITDATA](data))
+        : this[EMITDATA](data)
+    } else if (ev === 'end') {
+      return this[EMITEND]()
+    } else if (ev === 'close') {
+      this[CLOSED] = true
+      // don't emit close before 'end' and 'finish'
+      if (!this[EMITTED_END] && !this[DESTROYED])
+        return
+      const ret = super.emit('close')
+      this.removeAllListeners('close')
+      return ret
+    } else if (ev === 'error') {
+      this[EMITTED_ERROR] = data
+      const ret = super.emit('error', data)
+      this[MAYBE_EMIT_END]()
+      return ret
+    } else if (ev === 'resume') {
+      const ret = super.emit('resume')
+      this[MAYBE_EMIT_END]()
+      return ret
+    } else if (ev === 'finish' || ev === 'prefinish') {
+      const ret = super.emit(ev)
+      this.removeAllListeners(ev)
+      return ret
+    }
+
+    // Some other unknown event
+    const ret = super.emit(ev, data, ...extra)
+    this[MAYBE_EMIT_END]()
+    return ret
+  }
+
+  [EMITDATA] (data) {
+    for (const p of this.pipes) {
+      if (p.dest.write(data) === false)
+        this.pause()
+    }
+    const ret = super.emit('data', data)
+    this[MAYBE_EMIT_END]()
+    return ret
+  }
+
+  [EMITEND] () {
+    if (this[EMITTED_END])
+      return
+
+    this[EMITTED_END] = true
+    this.readable = false
+    if (this[ASYNC])
+      defer(() => this[EMITEND2]())
+    else
+      this[EMITEND2]()
+  }
+
+  [EMITEND2] () {
+    if (this[DECODER]) {
+      const data = this[DECODER].end()
+      if (data) {
+        for (const p of this.pipes) {
+          p.dest.write(data)
+        }
+        super.emit('data', data)
+      }
+    }
+
+    for (const p of this.pipes) {
+      p.end()
+    }
+    const ret = super.emit('end')
+    this.removeAllListeners('end')
+    return ret
+  }
+
+  // const all = await stream.collect()
+  collect () {
+    const buf = []
+    if (!this[OBJECTMODE])
+      buf.dataLength = 0
+    // set the promise first, in case an error is raised
+    // by triggering the flow here.
+    const p = this.promise()
+    this.on('data', c => {
+      buf.push(c)
+      if (!this[OBJECTMODE])
+        buf.dataLength += c.length
+    })
+    return p.then(() => buf)
+  }
+
+  // const data = await stream.concat()
+  concat () {
+    return this[OBJECTMODE]
+      ? Promise.reject(new Error('cannot concat in objectMode'))
+      : this.collect().then(buf =>
+          this[OBJECTMODE]
+            ? Promise.reject(new Error('cannot concat in objectMode'))
+            : this[ENCODING] ? buf.join('') : Buffer.concat(buf, buf.dataLength))
+  }
+
+  // stream.promise().then(() => done, er => emitted error)
+  promise () {
+    return new Promise((resolve, reject) => {
+      this.on(DESTROYED, () => reject(new Error('stream destroyed')))
+      this.on('error', er => reject(er))
+      this.on('end', () => resolve())
+    })
+  }
+
+  // for await (let chunk of stream)
+  [ASYNCITERATOR] () {
+    const next = () => {
+      const res = this.read()
+      if (res !== null)
+        return Promise.resolve({ done: false, value: res })
+
+      if (this[EOF])
+        return Promise.resolve({ done: true })
+
+      let resolve = null
+      let reject = null
+      const onerr = er => {
+        this.removeListener('data', ondata)
+        this.removeListener('end', onend)
+        reject(er)
+      }
+      const ondata = value => {
+        this.removeListener('error', onerr)
+        this.removeListener('end', onend)
+        this.pause()
+        resolve({ value: value, done: !!this[EOF] })
+      }
+      const onend = () => {
+        this.removeListener('error', onerr)
+        this.removeListener('data', ondata)
+        resolve({ done: true })
+      }
+      const ondestroy = () => onerr(new Error('stream destroyed'))
+      return new Promise((res, rej) => {
+        reject = rej
+        resolve = res
+        this.once(DESTROYED, ondestroy)
+        this.once('error', onerr)
+        this.once('end', onend)
+        this.once('data', ondata)
+      })
+    }
+
+    return { next }
+  }
+
+  // for (let chunk of stream)
+  [ITERATOR] () {
+    const next = () => {
+      const value = this.read()
+      const done = value === null
+      return { value, done }
+    }
+    return { next }
+  }
+
+  destroy (er) {
+    if (this[DESTROYED]) {
+      if (er)
+        this.emit('error', er)
+      else
+        this.emit(DESTROYED)
+      return this
+    }
+
+    this[DESTROYED] = true
+
+    // throw away all buffered data, it's never coming out
+    this.buffer.length = 0
+    this[BUFFERLENGTH] = 0
+
+    if (typeof this.close === 'function' && !this[CLOSED])
+      this.close()
+
+    if (er)
+      this.emit('error', er)
+    else // if no error to emit, still reject pending promises
+      this.emit(DESTROYED)
+
+    return this
+  }
+
+  static isStream (s) {
+    return !!s && (s instanceof Minipass || s instanceof Stream ||
+      s instanceof EE && (
+        typeof s.pipe === 'function' || // readable
+        (typeof s.write === 'function' && typeof s.end === 'function') // writable
+      ))
+  }
+}
diff --git a/server/node_modules/minipass/package.json b/server/node_modules/minipass/package.json
new file mode 100644
index 0000000..548d03f
--- /dev/null
+++ b/server/node_modules/minipass/package.json
@@ -0,0 +1,56 @@
+{
+  "name": "minipass",
+  "version": "3.3.6",
+  "description": "minimal implementation of a PassThrough stream",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "dependencies": {
+    "yallist": "^4.0.0"
+  },
+  "devDependencies": {
+    "@types/node": "^17.0.41",
+    "end-of-stream": "^1.4.0",
+    "prettier": "^2.6.2",
+    "tap": "^16.2.0",
+    "through2": "^2.0.3",
+    "ts-node": "^10.8.1",
+    "typescript": "^4.7.3"
+  },
+  "scripts": {
+    "test": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/isaacs/minipass.git"
+  },
+  "keywords": [
+    "passthrough",
+    "stream"
+  ],
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC",
+  "files": [
+    "index.d.ts",
+    "index.js"
+  ],
+  "tap": {
+    "check-coverage": true
+  },
+  "engines": {
+    "node": ">=8"
+  },
+  "prettier": {
+    "semi": false,
+    "printWidth": 80,
+    "tabWidth": 2,
+    "useTabs": false,
+    "singleQuote": true,
+    "jsxSingleQuote": false,
+    "bracketSameLine": true,
+    "arrowParens": "avoid",
+    "endOfLine": "lf"
+  }
+}
diff --git a/server/node_modules/minizlib/LICENSE b/server/node_modules/minizlib/LICENSE
new file mode 100644
index 0000000..ffce738
--- /dev/null
+++ b/server/node_modules/minizlib/LICENSE
@@ -0,0 +1,26 @@
+Minizlib was created by Isaac Z. Schlueter.
+It is a derivative work of the Node.js project.
+
+"""
+Copyright Isaac Z. Schlueter and Contributors
+Copyright Node.js contributors. All rights reserved.
+Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+"""
diff --git a/server/node_modules/minizlib/README.md b/server/node_modules/minizlib/README.md
new file mode 100644
index 0000000..80e067a
--- /dev/null
+++ b/server/node_modules/minizlib/README.md
@@ -0,0 +1,60 @@
+# minizlib
+
+A fast zlib stream built on [minipass](http://npm.im/minipass) and
+Node.js's zlib binding.
+
+This module was created to serve the needs of
+[node-tar](http://npm.im/tar) and
+[minipass-fetch](http://npm.im/minipass-fetch).
+
+Brotli is supported in versions of node with a Brotli binding.
+
+## How does this differ from the streams in `require('zlib')`?
+
+First, there are no convenience methods to compress or decompress a
+buffer.  If you want those, use the built-in `zlib` module.  This is
+only streams.  That being said, Minipass streams to make it fairly easy to
+use as one-liners: `new zlib.Deflate().end(data).read()` will return the
+deflate compressed result.
+
+This module compresses and decompresses the data as fast as you feed
+it in.  It is synchronous, and runs on the main process thread.  Zlib
+and Brotli operations can be high CPU, but they're very fast, and doing it
+this way means much less bookkeeping and artificial deferral.
+
+Node's built in zlib streams are built on top of `stream.Transform`.
+They do the maximally safe thing with respect to consistent
+asynchrony, buffering, and backpressure.
+
+See [Minipass](http://npm.im/minipass) for more on the differences between
+Node.js core streams and Minipass streams, and the convenience methods
+provided by that class.
+
+## Classes
+
+- Deflate
+- Inflate
+- Gzip
+- Gunzip
+- DeflateRaw
+- InflateRaw
+- Unzip
+- BrotliCompress (Node v10 and higher)
+- BrotliDecompress (Node v10 and higher)
+
+## USAGE
+
+```js
+const zlib = require('minizlib')
+const input = sourceOfCompressedData()
+const decode = new zlib.BrotliDecompress()
+const output = whereToWriteTheDecodedData()
+input.pipe(decode).pipe(output)
+```
+
+## REPRODUCIBLE BUILDS
+
+To create reproducible gzip compressed files across different operating
+systems, set `portable: true` in the options.  This causes minizlib to set
+the `OS` indicator in byte 9 of the extended gzip header to `0xFF` for
+'unknown'.
diff --git a/server/node_modules/minizlib/constants.js b/server/node_modules/minizlib/constants.js
new file mode 100644
index 0000000..641ebc7
--- /dev/null
+++ b/server/node_modules/minizlib/constants.js
@@ -0,0 +1,115 @@
+// Update with any zlib constants that are added or changed in the future.
+// Node v6 didn't export this, so we just hard code the version and rely
+// on all the other hard-coded values from zlib v4736.  When node v6
+// support drops, we can just export the realZlibConstants object.
+const realZlibConstants = require('zlib').constants ||
+  /* istanbul ignore next */ { ZLIB_VERNUM: 4736 }
+
+module.exports = Object.freeze(Object.assign(Object.create(null), {
+  Z_NO_FLUSH: 0,
+  Z_PARTIAL_FLUSH: 1,
+  Z_SYNC_FLUSH: 2,
+  Z_FULL_FLUSH: 3,
+  Z_FINISH: 4,
+  Z_BLOCK: 5,
+  Z_OK: 0,
+  Z_STREAM_END: 1,
+  Z_NEED_DICT: 2,
+  Z_ERRNO: -1,
+  Z_STREAM_ERROR: -2,
+  Z_DATA_ERROR: -3,
+  Z_MEM_ERROR: -4,
+  Z_BUF_ERROR: -5,
+  Z_VERSION_ERROR: -6,
+  Z_NO_COMPRESSION: 0,
+  Z_BEST_SPEED: 1,
+  Z_BEST_COMPRESSION: 9,
+  Z_DEFAULT_COMPRESSION: -1,
+  Z_FILTERED: 1,
+  Z_HUFFMAN_ONLY: 2,
+  Z_RLE: 3,
+  Z_FIXED: 4,
+  Z_DEFAULT_STRATEGY: 0,
+  DEFLATE: 1,
+  INFLATE: 2,
+  GZIP: 3,
+  GUNZIP: 4,
+  DEFLATERAW: 5,
+  INFLATERAW: 6,
+  UNZIP: 7,
+  BROTLI_DECODE: 8,
+  BROTLI_ENCODE: 9,
+  Z_MIN_WINDOWBITS: 8,
+  Z_MAX_WINDOWBITS: 15,
+  Z_DEFAULT_WINDOWBITS: 15,
+  Z_MIN_CHUNK: 64,
+  Z_MAX_CHUNK: Infinity,
+  Z_DEFAULT_CHUNK: 16384,
+  Z_MIN_MEMLEVEL: 1,
+  Z_MAX_MEMLEVEL: 9,
+  Z_DEFAULT_MEMLEVEL: 8,
+  Z_MIN_LEVEL: -1,
+  Z_MAX_LEVEL: 9,
+  Z_DEFAULT_LEVEL: -1,
+  BROTLI_OPERATION_PROCESS: 0,
+  BROTLI_OPERATION_FLUSH: 1,
+  BROTLI_OPERATION_FINISH: 2,
+  BROTLI_OPERATION_EMIT_METADATA: 3,
+  BROTLI_MODE_GENERIC: 0,
+  BROTLI_MODE_TEXT: 1,
+  BROTLI_MODE_FONT: 2,
+  BROTLI_DEFAULT_MODE: 0,
+  BROTLI_MIN_QUALITY: 0,
+  BROTLI_MAX_QUALITY: 11,
+  BROTLI_DEFAULT_QUALITY: 11,
+  BROTLI_MIN_WINDOW_BITS: 10,
+  BROTLI_MAX_WINDOW_BITS: 24,
+  BROTLI_LARGE_MAX_WINDOW_BITS: 30,
+  BROTLI_DEFAULT_WINDOW: 22,
+  BROTLI_MIN_INPUT_BLOCK_BITS: 16,
+  BROTLI_MAX_INPUT_BLOCK_BITS: 24,
+  BROTLI_PARAM_MODE: 0,
+  BROTLI_PARAM_QUALITY: 1,
+  BROTLI_PARAM_LGWIN: 2,
+  BROTLI_PARAM_LGBLOCK: 3,
+  BROTLI_PARAM_DISABLE_LITERAL_CONTEXT_MODELING: 4,
+  BROTLI_PARAM_SIZE_HINT: 5,
+  BROTLI_PARAM_LARGE_WINDOW: 6,
+  BROTLI_PARAM_NPOSTFIX: 7,
+  BROTLI_PARAM_NDIRECT: 8,
+  BROTLI_DECODER_RESULT_ERROR: 0,
+  BROTLI_DECODER_RESULT_SUCCESS: 1,
+  BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT: 2,
+  BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT: 3,
+  BROTLI_DECODER_PARAM_DISABLE_RING_BUFFER_REALLOCATION: 0,
+  BROTLI_DECODER_PARAM_LARGE_WINDOW: 1,
+  BROTLI_DECODER_NO_ERROR: 0,
+  BROTLI_DECODER_SUCCESS: 1,
+  BROTLI_DECODER_NEEDS_MORE_INPUT: 2,
+  BROTLI_DECODER_NEEDS_MORE_OUTPUT: 3,
+  BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_NIBBLE: -1,
+  BROTLI_DECODER_ERROR_FORMAT_RESERVED: -2,
+  BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_META_NIBBLE: -3,
+  BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_ALPHABET: -4,
+  BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_SAME: -5,
+  BROTLI_DECODER_ERROR_FORMAT_CL_SPACE: -6,
+  BROTLI_DECODER_ERROR_FORMAT_HUFFMAN_SPACE: -7,
+  BROTLI_DECODER_ERROR_FORMAT_CONTEXT_MAP_REPEAT: -8,
+  BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_1: -9,
+  BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_2: -10,
+  BROTLI_DECODER_ERROR_FORMAT_TRANSFORM: -11,
+  BROTLI_DECODER_ERROR_FORMAT_DICTIONARY: -12,
+  BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS: -13,
+  BROTLI_DECODER_ERROR_FORMAT_PADDING_1: -14,
+  BROTLI_DECODER_ERROR_FORMAT_PADDING_2: -15,
+  BROTLI_DECODER_ERROR_FORMAT_DISTANCE: -16,
+  BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET: -19,
+  BROTLI_DECODER_ERROR_INVALID_ARGUMENTS: -20,
+  BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MODES: -21,
+  BROTLI_DECODER_ERROR_ALLOC_TREE_GROUPS: -22,
+  BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MAP: -25,
+  BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_1: -26,
+  BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_2: -27,
+  BROTLI_DECODER_ERROR_ALLOC_BLOCK_TYPE_TREES: -30,
+  BROTLI_DECODER_ERROR_UNREACHABLE: -31,
+}, realZlibConstants))
diff --git a/server/node_modules/minizlib/index.js b/server/node_modules/minizlib/index.js
new file mode 100644
index 0000000..fbaf69e
--- /dev/null
+++ b/server/node_modules/minizlib/index.js
@@ -0,0 +1,348 @@
+'use strict'
+
+const assert = require('assert')
+const Buffer = require('buffer').Buffer
+const realZlib = require('zlib')
+
+const constants = exports.constants = require('./constants.js')
+const Minipass = require('minipass')
+
+const OriginalBufferConcat = Buffer.concat
+
+const _superWrite = Symbol('_superWrite')
+class ZlibError extends Error {
+  constructor (err) {
+    super('zlib: ' + err.message)
+    this.code = err.code
+    this.errno = err.errno
+    /* istanbul ignore if */
+    if (!this.code)
+      this.code = 'ZLIB_ERROR'
+
+    this.message = 'zlib: ' + err.message
+    Error.captureStackTrace(this, this.constructor)
+  }
+
+  get name () {
+    return 'ZlibError'
+  }
+}
+
+// the Zlib class they all inherit from
+// This thing manages the queue of requests, and returns
+// true or false if there is anything in the queue when
+// you call the .write() method.
+const _opts = Symbol('opts')
+const _flushFlag = Symbol('flushFlag')
+const _finishFlushFlag = Symbol('finishFlushFlag')
+const _fullFlushFlag = Symbol('fullFlushFlag')
+const _handle = Symbol('handle')
+const _onError = Symbol('onError')
+const _sawError = Symbol('sawError')
+const _level = Symbol('level')
+const _strategy = Symbol('strategy')
+const _ended = Symbol('ended')
+const _defaultFullFlush = Symbol('_defaultFullFlush')
+
+class ZlibBase extends Minipass {
+  constructor (opts, mode) {
+    if (!opts || typeof opts !== 'object')
+      throw new TypeError('invalid options for ZlibBase constructor')
+
+    super(opts)
+    this[_sawError] = false
+    this[_ended] = false
+    this[_opts] = opts
+
+    this[_flushFlag] = opts.flush
+    this[_finishFlushFlag] = opts.finishFlush
+    // this will throw if any options are invalid for the class selected
+    try {
+      this[_handle] = new realZlib[mode](opts)
+    } catch (er) {
+      // make sure that all errors get decorated properly
+      throw new ZlibError(er)
+    }
+
+    this[_onError] = (err) => {
+      // no sense raising multiple errors, since we abort on the first one.
+      if (this[_sawError])
+        return
+
+      this[_sawError] = true
+
+      // there is no way to cleanly recover.
+      // continuing only obscures problems.
+      this.close()
+      this.emit('error', err)
+    }
+
+    this[_handle].on('error', er => this[_onError](new ZlibError(er)))
+    this.once('end', () => this.close)
+  }
+
+  close () {
+    if (this[_handle]) {
+      this[_handle].close()
+      this[_handle] = null
+      this.emit('close')
+    }
+  }
+
+  reset () {
+    if (!this[_sawError]) {
+      assert(this[_handle], 'zlib binding closed')
+      return this[_handle].reset()
+    }
+  }
+
+  flush (flushFlag) {
+    if (this.ended)
+      return
+
+    if (typeof flushFlag !== 'number')
+      flushFlag = this[_fullFlushFlag]
+    this.write(Object.assign(Buffer.alloc(0), { [_flushFlag]: flushFlag }))
+  }
+
+  end (chunk, encoding, cb) {
+    if (chunk)
+      this.write(chunk, encoding)
+    this.flush(this[_finishFlushFlag])
+    this[_ended] = true
+    return super.end(null, null, cb)
+  }
+
+  get ended () {
+    return this[_ended]
+  }
+
+  write (chunk, encoding, cb) {
+    // process the chunk using the sync process
+    // then super.write() all the outputted chunks
+    if (typeof encoding === 'function')
+      cb = encoding, encoding = 'utf8'
+
+    if (typeof chunk === 'string')
+      chunk = Buffer.from(chunk, encoding)
+
+    if (this[_sawError])
+      return
+    assert(this[_handle], 'zlib binding closed')
+
+    // _processChunk tries to .close() the native handle after it's done, so we
+    // intercept that by temporarily making it a no-op.
+    const nativeHandle = this[_handle]._handle
+    const originalNativeClose = nativeHandle.close
+    nativeHandle.close = () => {}
+    const originalClose = this[_handle].close
+    this[_handle].close = () => {}
+    // It also calls `Buffer.concat()` at the end, which may be convenient
+    // for some, but which we are not interested in as it slows us down.
+    Buffer.concat = (args) => args
+    let result
+    try {
+      const flushFlag = typeof chunk[_flushFlag] === 'number'
+        ? chunk[_flushFlag] : this[_flushFlag]
+      result = this[_handle]._processChunk(chunk, flushFlag)
+      // if we don't throw, reset it back how it was
+      Buffer.concat = OriginalBufferConcat
+    } catch (err) {
+      // or if we do, put Buffer.concat() back before we emit error
+      // Error events call into user code, which may call Buffer.concat()
+      Buffer.concat = OriginalBufferConcat
+      this[_onError](new ZlibError(err))
+    } finally {
+      if (this[_handle]) {
+        // Core zlib resets `_handle` to null after attempting to close the
+        // native handle. Our no-op handler prevented actual closure, but we
+        // need to restore the `._handle` property.
+        this[_handle]._handle = nativeHandle
+        nativeHandle.close = originalNativeClose
+        this[_handle].close = originalClose
+        // `_processChunk()` adds an 'error' listener. If we don't remove it
+        // after each call, these handlers start piling up.
+        this[_handle].removeAllListeners('error')
+        // make sure OUR error listener is still attached tho
+      }
+    }
+
+    if (this[_handle])
+      this[_handle].on('error', er => this[_onError](new ZlibError(er)))
+
+    let writeReturn
+    if (result) {
+      if (Array.isArray(result) && result.length > 0) {
+        // The first buffer is always `handle._outBuffer`, which would be
+        // re-used for later invocations; so, we always have to copy that one.
+        writeReturn = this[_superWrite](Buffer.from(result[0]))
+        for (let i = 1; i < result.length; i++) {
+          writeReturn = this[_superWrite](result[i])
+        }
+      } else {
+        writeReturn = this[_superWrite](Buffer.from(result))
+      }
+    }
+
+    if (cb)
+      cb()
+    return writeReturn
+  }
+
+  [_superWrite] (data) {
+    return super.write(data)
+  }
+}
+
+class Zlib extends ZlibBase {
+  constructor (opts, mode) {
+    opts = opts || {}
+
+    opts.flush = opts.flush || constants.Z_NO_FLUSH
+    opts.finishFlush = opts.finishFlush || constants.Z_FINISH
+    super(opts, mode)
+
+    this[_fullFlushFlag] = constants.Z_FULL_FLUSH
+    this[_level] = opts.level
+    this[_strategy] = opts.strategy
+  }
+
+  params (level, strategy) {
+    if (this[_sawError])
+      return
+
+    if (!this[_handle])
+      throw new Error('cannot switch params when binding is closed')
+
+    // no way to test this without also not supporting params at all
+    /* istanbul ignore if */
+    if (!this[_handle].params)
+      throw new Error('not supported in this implementation')
+
+    if (this[_level] !== level || this[_strategy] !== strategy) {
+      this.flush(constants.Z_SYNC_FLUSH)
+      assert(this[_handle], 'zlib binding closed')
+      // .params() calls .flush(), but the latter is always async in the
+      // core zlib. We override .flush() temporarily to intercept that and
+      // flush synchronously.
+      const origFlush = this[_handle].flush
+      this[_handle].flush = (flushFlag, cb) => {
+        this.flush(flushFlag)
+        cb()
+      }
+      try {
+        this[_handle].params(level, strategy)
+      } finally {
+        this[_handle].flush = origFlush
+      }
+      /* istanbul ignore else */
+      if (this[_handle]) {
+        this[_level] = level
+        this[_strategy] = strategy
+      }
+    }
+  }
+}
+
+// minimal 2-byte header
+class Deflate extends Zlib {
+  constructor (opts) {
+    super(opts, 'Deflate')
+  }
+}
+
+class Inflate extends Zlib {
+  constructor (opts) {
+    super(opts, 'Inflate')
+  }
+}
+
+// gzip - bigger header, same deflate compression
+const _portable = Symbol('_portable')
+class Gzip extends Zlib {
+  constructor (opts) {
+    super(opts, 'Gzip')
+    this[_portable] = opts && !!opts.portable
+  }
+
+  [_superWrite] (data) {
+    if (!this[_portable])
+      return super[_superWrite](data)
+
+    // we'll always get the header emitted in one first chunk
+    // overwrite the OS indicator byte with 0xFF
+    this[_portable] = false
+    data[9] = 255
+    return super[_superWrite](data)
+  }
+}
+
+class Gunzip extends Zlib {
+  constructor (opts) {
+    super(opts, 'Gunzip')
+  }
+}
+
+// raw - no header
+class DeflateRaw extends Zlib {
+  constructor (opts) {
+    super(opts, 'DeflateRaw')
+  }
+}
+
+class InflateRaw extends Zlib {
+  constructor (opts) {
+    super(opts, 'InflateRaw')
+  }
+}
+
+// auto-detect header.
+class Unzip extends Zlib {
+  constructor (opts) {
+    super(opts, 'Unzip')
+  }
+}
+
+class Brotli extends ZlibBase {
+  constructor (opts, mode) {
+    opts = opts || {}
+
+    opts.flush = opts.flush || constants.BROTLI_OPERATION_PROCESS
+    opts.finishFlush = opts.finishFlush || constants.BROTLI_OPERATION_FINISH
+
+    super(opts, mode)
+
+    this[_fullFlushFlag] = constants.BROTLI_OPERATION_FLUSH
+  }
+}
+
+class BrotliCompress extends Brotli {
+  constructor (opts) {
+    super(opts, 'BrotliCompress')
+  }
+}
+
+class BrotliDecompress extends Brotli {
+  constructor (opts) {
+    super(opts, 'BrotliDecompress')
+  }
+}
+
+exports.Deflate = Deflate
+exports.Inflate = Inflate
+exports.Gzip = Gzip
+exports.Gunzip = Gunzip
+exports.DeflateRaw = DeflateRaw
+exports.InflateRaw = InflateRaw
+exports.Unzip = Unzip
+/* istanbul ignore else */
+if (typeof realZlib.BrotliCompress === 'function') {
+  exports.BrotliCompress = BrotliCompress
+  exports.BrotliDecompress = BrotliDecompress
+} else {
+  exports.BrotliCompress = exports.BrotliDecompress = class {
+    constructor () {
+      throw new Error('Brotli is not supported in this version of Node.js')
+    }
+  }
+}
diff --git a/server/node_modules/minizlib/package.json b/server/node_modules/minizlib/package.json
new file mode 100644
index 0000000..98825a5
--- /dev/null
+++ b/server/node_modules/minizlib/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "minizlib",
+  "version": "2.1.2",
+  "description": "A small fast zlib stream built on [minipass](http://npm.im/minipass) and Node.js's zlib binding.",
+  "main": "index.js",
+  "dependencies": {
+    "minipass": "^3.0.0",
+    "yallist": "^4.0.0"
+  },
+  "scripts": {
+    "test": "tap test/*.js --100 -J",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --all; git push origin --tags"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/isaacs/minizlib.git"
+  },
+  "keywords": [
+    "zlib",
+    "gzip",
+    "gunzip",
+    "deflate",
+    "inflate",
+    "compression",
+    "zip",
+    "unzip"
+  ],
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "MIT",
+  "devDependencies": {
+    "tap": "^14.6.9"
+  },
+  "files": [
+    "index.js",
+    "constants.js"
+  ],
+  "engines": {
+    "node": ">= 8"
+  }
+}
diff --git a/server/node_modules/mkdirp-classic/LICENSE b/server/node_modules/mkdirp-classic/LICENSE
new file mode 100644
index 0000000..f6b3a0d
--- /dev/null
+++ b/server/node_modules/mkdirp-classic/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2020 James Halliday (mail@substack.net) and Mathias Buus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/mkdirp-classic/README.md b/server/node_modules/mkdirp-classic/README.md
new file mode 100644
index 0000000..be5ac93
--- /dev/null
+++ b/server/node_modules/mkdirp-classic/README.md
@@ -0,0 +1,18 @@
+# mkdirp-classic
+
+Just a non-deprecated mirror of [mkdirp 0.5.2](https://github.com/substack/node-mkdirp/tree/0.5.1)
+for use in modules where we depend on the non promise interface.
+
+```
+npm install mkdirp-classic
+```
+
+## Usage
+
+``` js
+// See the above link
+```
+
+## License
+
+MIT
diff --git a/server/node_modules/mkdirp-classic/index.js b/server/node_modules/mkdirp-classic/index.js
new file mode 100644
index 0000000..6ce241b
--- /dev/null
+++ b/server/node_modules/mkdirp-classic/index.js
@@ -0,0 +1,98 @@
+var path = require('path');
+var fs = require('fs');
+var _0777 = parseInt('0777', 8);
+
+module.exports = mkdirP.mkdirp = mkdirP.mkdirP = mkdirP;
+
+function mkdirP (p, opts, f, made) {
+    if (typeof opts === 'function') {
+        f = opts;
+        opts = {};
+    }
+    else if (!opts || typeof opts !== 'object') {
+        opts = { mode: opts };
+    }
+    
+    var mode = opts.mode;
+    var xfs = opts.fs || fs;
+    
+    if (mode === undefined) {
+        mode = _0777 & (~process.umask());
+    }
+    if (!made) made = null;
+    
+    var cb = f || function () {};
+    p = path.resolve(p);
+    
+    xfs.mkdir(p, mode, function (er) {
+        if (!er) {
+            made = made || p;
+            return cb(null, made);
+        }
+        switch (er.code) {
+            case 'ENOENT':
+                mkdirP(path.dirname(p), opts, function (er, made) {
+                    if (er) cb(er, made);
+                    else mkdirP(p, opts, cb, made);
+                });
+                break;
+
+            // In the case of any other error, just see if there's a dir
+            // there already.  If so, then hooray!  If not, then something
+            // is borked.
+            default:
+                xfs.stat(p, function (er2, stat) {
+                    // if the stat fails, then that's super weird.
+                    // let the original error be the failure reason.
+                    if (er2 || !stat.isDirectory()) cb(er, made)
+                    else cb(null, made);
+                });
+                break;
+        }
+    });
+}
+
+mkdirP.sync = function sync (p, opts, made) {
+    if (!opts || typeof opts !== 'object') {
+        opts = { mode: opts };
+    }
+    
+    var mode = opts.mode;
+    var xfs = opts.fs || fs;
+    
+    if (mode === undefined) {
+        mode = _0777 & (~process.umask());
+    }
+    if (!made) made = null;
+
+    p = path.resolve(p);
+
+    try {
+        xfs.mkdirSync(p, mode);
+        made = made || p;
+    }
+    catch (err0) {
+        switch (err0.code) {
+            case 'ENOENT' :
+                made = sync(path.dirname(p), opts, made);
+                sync(p, opts, made);
+                break;
+
+            // In the case of any other error, just see if there's a dir
+            // there already.  If so, then hooray!  If not, then something
+            // is borked.
+            default:
+                var stat;
+                try {
+                    stat = xfs.statSync(p);
+                }
+                catch (err1) {
+                    throw err0;
+                }
+                if (!stat.isDirectory()) throw err0;
+                break;
+        }
+    }
+
+    return made;
+};
diff --git a/server/node_modules/mkdirp-classic/package.json b/server/node_modules/mkdirp-classic/package.json
new file mode 100644
index 0000000..c8b5407
--- /dev/null
+++ b/server/node_modules/mkdirp-classic/package.json
@@ -0,0 +1,18 @@
+{
+  "name": "mkdirp-classic",
+  "version": "0.5.3",
+  "description": "Mirror of mkdirp 0.5.2",
+  "main": "index.js",
+  "dependencies": {},
+  "devDependencies": {},
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/mafintosh/mkdirp-classic.git"
+  },
+  "author": "Mathias Buus (@mafintosh)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/mafintosh/mkdirp-classic/issues"
+  },
+  "homepage": "https://github.com/mafintosh/mkdirp-classic"
+}
diff --git a/server/node_modules/mkdirp/LICENSE b/server/node_modules/mkdirp/LICENSE
new file mode 100644
index 0000000..432d1ae
--- /dev/null
+++ b/server/node_modules/mkdirp/LICENSE
@@ -0,0 +1,21 @@
+Copyright 2010 James Halliday (mail@substack.net)
+
+This project is free software released under the MIT/X11 license:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/mkdirp/bin/cmd.js b/server/node_modules/mkdirp/bin/cmd.js
new file mode 100755
index 0000000..d95de15
--- /dev/null
+++ b/server/node_modules/mkdirp/bin/cmd.js
@@ -0,0 +1,33 @@
+#!/usr/bin/env node
+
+var mkdirp = require('../');
+var minimist = require('minimist');
+var fs = require('fs');
+
+var argv = minimist(process.argv.slice(2), {
+    alias: { m: 'mode', h: 'help' },
+    string: [ 'mode' ]
+});
+if (argv.help) {
+    fs.createReadStream(__dirname + '/usage.txt').pipe(process.stdout);
+    return;
+}
+
+var paths = argv._.slice();
+var mode = argv.mode ? parseInt(argv.mode, 8) : undefined;
+
+(function next () {
+    if (paths.length === 0) return;
+    var p = paths.shift();
+    
+    if (mode === undefined) mkdirp(p, cb)
+    else mkdirp(p, mode, cb)
+    
+    function cb (err) {
+        if (err) {
+            console.error(err.message);
+            process.exit(1);
+        }
+        else next();
+    }
+})();
diff --git a/server/node_modules/mkdirp/bin/usage.txt b/server/node_modules/mkdirp/bin/usage.txt
new file mode 100644
index 0000000..f952aa2
--- /dev/null
+++ b/server/node_modules/mkdirp/bin/usage.txt
@@ -0,0 +1,12 @@
+usage: mkdirp [DIR1,DIR2..] {OPTIONS}
+
+  Create each supplied directory including any necessary parent directories that
+  don't yet exist.
+  
+  If the directory already exists, do nothing.
+
+OPTIONS are:
+
+  -m, --mode   If a directory needs to be created, set the mode as an octal
+               permission string.
+
diff --git a/server/node_modules/mkdirp/index.js b/server/node_modules/mkdirp/index.js
new file mode 100644
index 0000000..0890ac3
--- /dev/null
+++ b/server/node_modules/mkdirp/index.js
@@ -0,0 +1,102 @@
+var path = require('path');
+var fs = require('fs');
+var _0777 = parseInt('0777', 8);
+
+module.exports = mkdirP.mkdirp = mkdirP.mkdirP = mkdirP;
+
+function mkdirP (p, opts, f, made) {
+    if (typeof opts === 'function') {
+        f = opts;
+        opts = {};
+    }
+    else if (!opts || typeof opts !== 'object') {
+        opts = { mode: opts };
+    }
+    
+    var mode = opts.mode;
+    var xfs = opts.fs || fs;
+    
+    if (mode === undefined) {
+        mode = _0777
+    }
+    if (!made) made = null;
+    
+    var cb = f || /* istanbul ignore next */ function () {};
+    p = path.resolve(p);
+    
+    xfs.mkdir(p, mode, function (er) {
+        if (!er) {
+            made = made || p;
+            return cb(null, made);
+        }
+        switch (er.code) {
+            case 'ENOENT':
+                /* istanbul ignore if */
+                if (path.dirname(p) === p) return cb(er);
+                mkdirP(path.dirname(p), opts, function (er, made) {
+                    /* istanbul ignore if */
+                    if (er) cb(er, made);
+                    else mkdirP(p, opts, cb, made);
+                });
+                break;
+
+            // In the case of any other error, just see if there's a dir
+            // there already.  If so, then hooray!  If not, then something
+            // is borked.
+            default:
+                xfs.stat(p, function (er2, stat) {
+                    // if the stat fails, then that's super weird.
+                    // let the original error be the failure reason.
+                    if (er2 || !stat.isDirectory()) cb(er, made)
+                    else cb(null, made);
+                });
+                break;
+        }
+    });
+}
+
+mkdirP.sync = function sync (p, opts, made) {
+    if (!opts || typeof opts !== 'object') {
+        opts = { mode: opts };
+    }
+    
+    var mode = opts.mode;
+    var xfs = opts.fs || fs;
+    
+    if (mode === undefined) {
+        mode = _0777
+    }
+    if (!made) made = null;
+
+    p = path.resolve(p);
+
+    try {
+        xfs.mkdirSync(p, mode);
+        made = made || p;
+    }
+    catch (err0) {
+        switch (err0.code) {
+            case 'ENOENT' :
+                made = sync(path.dirname(p), opts, made);
+                sync(p, opts, made);
+                break;
+
+            // In the case of any other error, just see if there's a dir
+            // there already.  If so, then hooray!  If not, then something
+            // is borked.
+            default:
+                var stat;
+                try {
+                    stat = xfs.statSync(p);
+                }
+                catch (err1) /* istanbul ignore next */ {
+                    throw err0;
+                }
+                /* istanbul ignore if */
+                if (!stat.isDirectory()) throw err0;
+                break;
+        }
+    }
+
+    return made;
+};
diff --git a/server/node_modules/mkdirp/package.json b/server/node_modules/mkdirp/package.json
new file mode 100644
index 0000000..951e58d
--- /dev/null
+++ b/server/node_modules/mkdirp/package.json
@@ -0,0 +1,33 @@
+{
+  "name": "mkdirp",
+  "description": "Recursively mkdir, like `mkdir -p`",
+  "version": "0.5.6",
+  "publishConfig": {
+    "tag": "legacy"
+  },
+  "author": "James Halliday <mail@substack.net> (http://substack.net)",
+  "main": "index.js",
+  "keywords": [
+    "mkdir",
+    "directory"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/substack/node-mkdirp.git"
+  },
+  "scripts": {
+    "test": "tap test/*.js"
+  },
+  "dependencies": {
+    "minimist": "^1.2.6"
+  },
+  "devDependencies": {
+    "tap": "^16.0.1"
+  },
+  "bin": "bin/cmd.js",
+  "license": "MIT",
+  "files": [
+    "bin",
+    "index.js"
+  ]
+}
diff --git a/server/node_modules/mkdirp/readme.markdown b/server/node_modules/mkdirp/readme.markdown
new file mode 100644
index 0000000..fc314bf
--- /dev/null
+++ b/server/node_modules/mkdirp/readme.markdown
@@ -0,0 +1,100 @@
+# mkdirp
+
+Like `mkdir -p`, but in node.js!
+
+[![build status](https://secure.travis-ci.org/substack/node-mkdirp.png)](http://travis-ci.org/substack/node-mkdirp)
+
+# example
+
+## pow.js
+
+```js
+var mkdirp = require('mkdirp');
+    
+mkdirp('/tmp/foo/bar/baz', function (err) {
+    if (err) console.error(err)
+    else console.log('pow!')
+});
+```
+
+Output
+
+```
+pow!
+```
+
+And now /tmp/foo/bar/baz exists, huzzah!
+
+# methods
+
+```js
+var mkdirp = require('mkdirp');
+```
+
+## mkdirp(dir, opts, cb)
+
+Create a new directory and any necessary subdirectories at `dir` with octal
+permission string `opts.mode`. If `opts` is a non-object, it will be treated as
+the `opts.mode`.
+
+If `opts.mode` isn't specified, it defaults to `0777`.
+
+`cb(err, made)` fires with the error or the first directory `made`
+that had to be created, if any.
+
+You can optionally pass in an alternate `fs` implementation by passing in
+`opts.fs`. Your implementation should have `opts.fs.mkdir(path, mode, cb)` and
+`opts.fs.stat(path, cb)`.
+
+## mkdirp.sync(dir, opts)
+
+Synchronously create a new directory and any necessary subdirectories at `dir`
+with octal permission string `opts.mode`. If `opts` is a non-object, it will be
+treated as the `opts.mode`.
+
+If `opts.mode` isn't specified, it defaults to `0777`.
+
+Returns the first directory that had to be created, if any.
+
+You can optionally pass in an alternate `fs` implementation by passing in
+`opts.fs`. Your implementation should have `opts.fs.mkdirSync(path, mode)` and
+`opts.fs.statSync(path)`.
+
+# usage
+
+This package also ships with a `mkdirp` command.
+
+```
+usage: mkdirp [DIR1,DIR2..] {OPTIONS}
+
+  Create each supplied directory including any necessary parent directories that
+  don't yet exist.
+  
+  If the directory already exists, do nothing.
+
+OPTIONS are:
+
+  -m, --mode   If a directory needs to be created, set the mode as an octal
+               permission string.
+
+```
+
+# install
+
+With [npm](http://npmjs.org) do:
+
+```
+npm install mkdirp
+```
+
+to get the library, or
+
+```
+npm install -g mkdirp
+```
+
+to get the command.
+
+# license
+
+MIT
diff --git a/server/node_modules/ms/index.js b/server/node_modules/ms/index.js
new file mode 100644
index 0000000..6a522b1
--- /dev/null
+++ b/server/node_modules/ms/index.js
@@ -0,0 +1,152 @@
+/**
+ * Helpers.
+ */
+
+var s = 1000;
+var m = s * 60;
+var h = m * 60;
+var d = h * 24;
+var y = d * 365.25;
+
+/**
+ * Parse or format the given `val`.
+ *
+ * Options:
+ *
+ *  - `long` verbose formatting [false]
+ *
+ * @param {String|Number} val
+ * @param {Object} [options]
+ * @throws {Error} throw an error if val is not a non-empty string or a number
+ * @return {String|Number}
+ * @api public
+ */
+
+module.exports = function(val, options) {
+  options = options || {};
+  var type = typeof val;
+  if (type === 'string' && val.length > 0) {
+    return parse(val);
+  } else if (type === 'number' && isNaN(val) === false) {
+    return options.long ? fmtLong(val) : fmtShort(val);
+  }
+  throw new Error(
+    'val is not a non-empty string or a valid number. val=' +
+      JSON.stringify(val)
+  );
+};
+
+/**
+ * Parse the given `str` and return milliseconds.
+ *
+ * @param {String} str
+ * @return {Number}
+ * @api private
+ */
+
+function parse(str) {
+  str = String(str);
+  if (str.length > 100) {
+    return;
+  }
+  var match = /^((?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|years?|yrs?|y)?$/i.exec(
+    str
+  );
+  if (!match) {
+    return;
+  }
+  var n = parseFloat(match[1]);
+  var type = (match[2] || 'ms').toLowerCase();
+  switch (type) {
+    case 'years':
+    case 'year':
+    case 'yrs':
+    case 'yr':
+    case 'y':
+      return n * y;
+    case 'days':
+    case 'day':
+    case 'd':
+      return n * d;
+    case 'hours':
+    case 'hour':
+    case 'hrs':
+    case 'hr':
+    case 'h':
+      return n * h;
+    case 'minutes':
+    case 'minute':
+    case 'mins':
+    case 'min':
+    case 'm':
+      return n * m;
+    case 'seconds':
+    case 'second':
+    case 'secs':
+    case 'sec':
+    case 's':
+      return n * s;
+    case 'milliseconds':
+    case 'millisecond':
+    case 'msecs':
+    case 'msec':
+    case 'ms':
+      return n;
+    default:
+      return undefined;
+  }
+}
+
+/**
+ * Short format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtShort(ms) {
+  if (ms >= d) {
+    return Math.round(ms / d) + 'd';
+  }
+  if (ms >= h) {
+    return Math.round(ms / h) + 'h';
+  }
+  if (ms >= m) {
+    return Math.round(ms / m) + 'm';
+  }
+  if (ms >= s) {
+    return Math.round(ms / s) + 's';
+  }
+  return ms + 'ms';
+}
+
+/**
+ * Long format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtLong(ms) {
+  return plural(ms, d, 'day') ||
+    plural(ms, h, 'hour') ||
+    plural(ms, m, 'minute') ||
+    plural(ms, s, 'second') ||
+    ms + ' ms';
+}
+
+/**
+ * Pluralization helper.
+ */
+
+function plural(ms, n, name) {
+  if (ms < n) {
+    return;
+  }
+  if (ms < n * 1.5) {
+    return Math.floor(ms / n) + ' ' + name;
+  }
+  return Math.ceil(ms / n) + ' ' + name + 's';
+}
diff --git a/server/node_modules/ms/license.md b/server/node_modules/ms/license.md
new file mode 100644
index 0000000..69b6125
--- /dev/null
+++ b/server/node_modules/ms/license.md
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 Zeit, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/ms/package.json b/server/node_modules/ms/package.json
new file mode 100644
index 0000000..6a31c81
--- /dev/null
+++ b/server/node_modules/ms/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "ms",
+  "version": "2.0.0",
+  "description": "Tiny milisecond conversion utility",
+  "repository": "zeit/ms",
+  "main": "./index",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "precommit": "lint-staged",
+    "lint": "eslint lib/* bin/*",
+    "test": "mocha tests.js"
+  },
+  "eslintConfig": {
+    "extends": "eslint:recommended",
+    "env": {
+      "node": true,
+      "es6": true
+    }
+  },
+  "lint-staged": {
+    "*.js": [
+      "npm run lint",
+      "prettier --single-quote --write",
+      "git add"
+    ]
+  },
+  "license": "MIT",
+  "devDependencies": {
+    "eslint": "3.19.0",
+    "expect.js": "0.3.1",
+    "husky": "0.13.3",
+    "lint-staged": "3.4.1",
+    "mocha": "3.4.1"
+  }
+}
diff --git a/server/node_modules/ms/readme.md b/server/node_modules/ms/readme.md
new file mode 100644
index 0000000..84a9974
--- /dev/null
+++ b/server/node_modules/ms/readme.md
@@ -0,0 +1,51 @@
+# ms
+
+[![Build Status](https://travis-ci.org/zeit/ms.svg?branch=master)](https://travis-ci.org/zeit/ms)
+[![Slack Channel](http://zeit-slackin.now.sh/badge.svg)](https://zeit.chat/)
+
+Use this package to easily convert various time formats to milliseconds.
+
+## Examples
+
+```js
+ms('2 days')  // 172800000
+ms('1d')      // 86400000
+ms('10h')     // 36000000
+ms('2.5 hrs') // 9000000
+ms('2h')      // 7200000
+ms('1m')      // 60000
+ms('5s')      // 5000
+ms('1y')      // 31557600000
+ms('100')     // 100
+```
+
+### Convert from milliseconds
+
+```js
+ms(60000)             // "1m"
+ms(2 * 60000)         // "2m"
+ms(ms('10 hours'))    // "10h"
+```
+
+### Time format written-out
+
+```js
+ms(60000, { long: true })             // "1 minute"
+ms(2 * 60000, { long: true })         // "2 minutes"
+ms(ms('10 hours'), { long: true })    // "10 hours"
+```
+
+## Features
+
+- Works both in [node](https://nodejs.org) and in the browser.
+- If a number is supplied to `ms`, a string with a unit is returned.
+- If a string that contains the number is supplied, it returns it as a number (e.g.: it returns `100` for `'100'`).
+- If you pass a string with a number and a valid unit, the number of equivalent ms is returned.
+
+## Caught a bug?
+
+1. [Fork](https://help.github.com/articles/fork-a-repo/) this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device
+2. Link the package to the global module directory: `npm link`
+3. Within the module you want to test your local development instance of ms, just link it to the dependencies: `npm link ms`. Instead of the default one from npm, node will now use your clone of ms!
+
+As always, you can run the tests using: `npm test`
diff --git a/server/node_modules/multer/LICENSE b/server/node_modules/multer/LICENSE
new file mode 100644
index 0000000..6c011b1
--- /dev/null
+++ b/server/node_modules/multer/LICENSE
@@ -0,0 +1,17 @@
+Copyright (c) 2014 Hage Yaapa <[http://www.hacksparrow.com](http://www.hacksparrow.com)>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/multer/README.md b/server/node_modules/multer/README.md
new file mode 100644
index 0000000..7f5d080
--- /dev/null
+++ b/server/node_modules/multer/README.md
@@ -0,0 +1,333 @@
+# Multer [![Build Status](https://travis-ci.org/expressjs/multer.svg?branch=master)](https://travis-ci.org/expressjs/multer) [![NPM version](https://badge.fury.io/js/multer.svg)](https://badge.fury.io/js/multer) [![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat)](https://github.com/feross/standard)
+
+Multer is a node.js middleware for handling `multipart/form-data`, which is primarily used for uploading files. It is written
+on top of [busboy](https://github.com/mscdex/busboy) for maximum efficiency.
+
+**NOTE**: Multer will not process any form which is not multipart (`multipart/form-data`).
+
+## Translations 
+
+This README is also available in other languages:
+
+- [Español](https://github.com/expressjs/multer/blob/master/doc/README-es.md) (Spanish)
+- [简体中文](https://github.com/expressjs/multer/blob/master/doc/README-zh-cn.md) (Chinese)
+- [한국어](https://github.com/expressjs/multer/blob/master/doc/README-ko.md) (Korean)
+- [Русский язык](https://github.com/expressjs/multer/blob/master/doc/README-ru.md) (Russian)
+- [Việt Nam](https://github.com/expressjs/multer/blob/master/doc/README-vi.md) (Vietnam)
+- [Português](https://github.com/expressjs/multer/blob/master/doc/README-pt-br.md) (Portuguese Brazil)
+
+## Installation
+
+```sh
+$ npm install --save multer
+```
+
+## Usage
+
+Multer adds a `body` object and a `file` or `files` object to the `request` object. The `body` object contains the values of the text fields of the form, the `file` or `files` object contains the files uploaded via the form.
+
+Basic usage example:
+
+Don't forget the `enctype="multipart/form-data"` in your form.
+
+```html
+<form action="/profile" method="post" enctype="multipart/form-data">
+  <input type="file" name="avatar" />
+</form>
+```
+
+```javascript
+const express = require('express')
+const multer  = require('multer')
+const upload = multer({ dest: 'uploads/' })
+
+const app = express()
+
+app.post('/profile', upload.single('avatar'), function (req, res, next) {
+  // req.file is the `avatar` file
+  // req.body will hold the text fields, if there were any
+})
+
+app.post('/photos/upload', upload.array('photos', 12), function (req, res, next) {
+  // req.files is array of `photos` files
+  // req.body will contain the text fields, if there were any
+})
+
+const cpUpload = upload.fields([{ name: 'avatar', maxCount: 1 }, { name: 'gallery', maxCount: 8 }])
+app.post('/cool-profile', cpUpload, function (req, res, next) {
+  // req.files is an object (String -> Array) where fieldname is the key, and the value is array of files
+  //
+  // e.g.
+  //  req.files['avatar'][0] -> File
+  //  req.files['gallery'] -> Array
+  //
+  // req.body will contain the text fields, if there were any
+})
+```
+
+In case you need to handle a text-only multipart form, you should use the `.none()` method:
+
+```javascript
+const express = require('express')
+const app = express()
+const multer  = require('multer')
+const upload = multer()
+
+app.post('/profile', upload.none(), function (req, res, next) {
+  // req.body contains the text fields
+})
+```
+
+Here's an example on how multer is used an HTML form. Take special note of the `enctype="multipart/form-data"` and `name="uploaded_file"` fields:
+
+```html
+<form action="/stats" enctype="multipart/form-data" method="post">
+  <div class="form-group">
+    <input type="file" class="form-control-file" name="uploaded_file">
+    <input type="text" class="form-control" placeholder="Number of speakers" name="nspeakers">
+    <input type="submit" value="Get me the stats!" class="btn btn-default">            
+  </div>
+</form>
+```
+
+Then in your javascript file you would add these lines to access both the file and the body. It is important that you use the `name` field value from the form in your upload function. This tells multer which field on the request it should look for the files in. If these fields aren't the same in the HTML form and on your server, your upload will fail:
+
+```javascript
+const multer  = require('multer')
+const upload = multer({ dest: './public/data/uploads/' })
+app.post('/stats', upload.single('uploaded_file'), function (req, res) {
+   // req.file is the name of your file in the form above, here 'uploaded_file'
+   // req.body will hold the text fields, if there were any 
+   console.log(req.file, req.body)
+});
+```
+
+
+
+## API
+
+### File information
+
+Each file contains the following information:
+
+Key | Description | Note
+--- | --- | ---
+`fieldname` | Field name specified in the form |
+`originalname` | Name of the file on the user's computer |
+`encoding` | Encoding type of the file |
+`mimetype` | Mime type of the file |
+`size` | Size of the file in bytes |
+`destination` | The folder to which the file has been saved | `DiskStorage`
+`filename` | The name of the file within the `destination` | `DiskStorage`
+`path` | The full path to the uploaded file | `DiskStorage`
+`buffer` | A `Buffer` of the entire file | `MemoryStorage`
+
+### `multer(opts)`
+
+Multer accepts an options object, the most basic of which is the `dest`
+property, which tells Multer where to upload the files. In case you omit the
+options object, the files will be kept in memory and never written to disk.
+
+By default, Multer will rename the files so as to avoid naming conflicts. The
+renaming function can be customized according to your needs.
+
+The following are the options that can be passed to Multer.
+
+Key | Description
+--- | ---
+`dest` or `storage` | Where to store the files
+`fileFilter` | Function to control which files are accepted
+`limits` | Limits of the uploaded data
+`preservePath` | Keep the full path of files instead of just the base name
+
+In an average web app, only `dest` might be required, and configured as shown in
+the following example.
+
+```javascript
+const upload = multer({ dest: 'uploads/' })
+```
+
+If you want more control over your uploads, you'll want to use the `storage`
+option instead of `dest`. Multer ships with storage engines `DiskStorage`
+and `MemoryStorage`; More engines are available from third parties.
+
+#### `.single(fieldname)`
+
+Accept a single file with the name `fieldname`. The single file will be stored
+in `req.file`.
+
+#### `.array(fieldname[, maxCount])`
+
+Accept an array of files, all with the name `fieldname`. Optionally error out if
+more than `maxCount` files are uploaded. The array of files will be stored in
+`req.files`.
+
+#### `.fields(fields)`
+
+Accept a mix of files, specified by `fields`. An object with arrays of files
+will be stored in `req.files`.
+
+`fields` should be an array of objects with `name` and optionally a `maxCount`.
+Example:
+
+```javascript
+[
+  { name: 'avatar', maxCount: 1 },
+  { name: 'gallery', maxCount: 8 }
+]
+```
+
+#### `.none()`
+
+Accept only text fields. If any file upload is made, error with code
+"LIMIT\_UNEXPECTED\_FILE" will be issued.
+
+#### `.any()`
+
+Accepts all files that comes over the wire. An array of files will be stored in
+`req.files`.
+
+**WARNING:** Make sure that you always handle the files that a user uploads.
+Never add multer as a global middleware since a malicious user could upload
+files to a route that you didn't anticipate. Only use this function on routes
+where you are handling the uploaded files.
+
+### `storage`
+
+#### `DiskStorage`
+
+The disk storage engine gives you full control on storing files to disk.
+
+```javascript
+const storage = multer.diskStorage({
+  destination: function (req, file, cb) {
+    cb(null, '/tmp/my-uploads')
+  },
+  filename: function (req, file, cb) {
+    const uniqueSuffix = Date.now() + '-' + Math.round(Math.random() * 1E9)
+    cb(null, file.fieldname + '-' + uniqueSuffix)
+  }
+})
+
+const upload = multer({ storage: storage })
+```
+
+There are two options available, `destination` and `filename`. They are both
+functions that determine where the file should be stored.
+
+`destination` is used to determine within which folder the uploaded files should
+be stored. This can also be given as a `string` (e.g. `'/tmp/uploads'`). If no
+`destination` is given, the operating system's default directory for temporary
+files is used.
+
+**Note:** You are responsible for creating the directory when providing
+`destination` as a function. When passing a string, multer will make sure that
+the directory is created for you.
+
+`filename` is used to determine what the file should be named inside the folder.
+If no `filename` is given, each file will be given a random name that doesn't
+include any file extension.
+
+**Note:** Multer will not append any file extension for you, your function
+should return a filename complete with an file extension.
+
+Each function gets passed both the request (`req`) and some information about
+the file (`file`) to aid with the decision.
+
+Note that `req.body` might not have been fully populated yet. It depends on the
+order that the client transmits fields and files to the server.
+
+For understanding the calling convention used in the callback (needing to pass
+null as the first param), refer to
+[Node.js error handling](https://www.joyent.com/node-js/production/design/errors)
+
+#### `MemoryStorage`
+
+The memory storage engine stores the files in memory as `Buffer` objects. It
+doesn't have any options.
+
+```javascript
+const storage = multer.memoryStorage()
+const upload = multer({ storage: storage })
+```
+
+When using memory storage, the file info will contain a field called
+`buffer` that contains the entire file.
+
+**WARNING**: Uploading very large files, or relatively small files in large
+numbers very quickly, can cause your application to run out of memory when
+memory storage is used.
+
+### `limits`
+
+An object specifying the size limits of the following optional properties. Multer passes this object into busboy directly, and the details of the properties can be found on [busboy's page](https://github.com/mscdex/busboy#busboy-methods).
+
+The following integer values are available:
+
+Key | Description | Default
+--- | --- | ---
+`fieldNameSize` | Max field name size | 100 bytes
+`fieldSize` | Max field value size (in bytes) | 1MB
+`fields` | Max number of non-file fields | Infinity
+`fileSize` | For multipart forms, the max file size (in bytes) | Infinity
+`files` | For multipart forms, the max number of file fields | Infinity
+`parts` | For multipart forms, the max number of parts (fields + files) | Infinity
+`headerPairs` | For multipart forms, the max number of header key=>value pairs to parse | 2000
+
+Specifying the limits can help protect your site against denial of service (DoS) attacks.
+
+### `fileFilter`
+
+Set this to a function to control which files should be uploaded and which
+should be skipped. The function should look like this:
+
+```javascript
+function fileFilter (req, file, cb) {
+
+  // The function should call `cb` with a boolean
+  // to indicate if the file should be accepted
+
+  // To reject this file pass `false`, like so:
+  cb(null, false)
+
+  // To accept the file pass `true`, like so:
+  cb(null, true)
+
+  // You can always pass an error if something goes wrong:
+  cb(new Error('I don\'t have a clue!'))
+
+}
+```
+
+## Error handling
+
+When encountering an error, Multer will delegate the error to Express. You can
+display a nice error page using [the standard express way](http://expressjs.com/guide/error-handling.html).
+
+If you want to catch errors specifically from Multer, you can call the
+middleware function by yourself. Also, if you want to catch only [the Multer errors](https://github.com/expressjs/multer/blob/master/lib/multer-error.js), you can use the `MulterError` class that is attached to the `multer` object itself (e.g. `err instanceof multer.MulterError`).
+
+```javascript
+const multer = require('multer')
+const upload = multer().single('avatar')
+
+app.post('/profile', function (req, res) {
+  upload(req, res, function (err) {
+    if (err instanceof multer.MulterError) {
+      // A Multer error occurred when uploading.
+    } else if (err) {
+      // An unknown error occurred when uploading.
+    }
+
+    // Everything went fine.
+  })
+})
+```
+
+## Custom storage engine
+
+For information on how to build your own storage engine, see [Multer Storage Engine](https://github.com/expressjs/multer/blob/master/StorageEngine.md).
+
+## License
+
+[MIT](LICENSE)
diff --git a/server/node_modules/multer/index.js b/server/node_modules/multer/index.js
new file mode 100644
index 0000000..d5b67eb
--- /dev/null
+++ b/server/node_modules/multer/index.js
@@ -0,0 +1,104 @@
+var makeMiddleware = require('./lib/make-middleware')
+
+var diskStorage = require('./storage/disk')
+var memoryStorage = require('./storage/memory')
+var MulterError = require('./lib/multer-error')
+
+function allowAll (req, file, cb) {
+  cb(null, true)
+}
+
+function Multer (options) {
+  if (options.storage) {
+    this.storage = options.storage
+  } else if (options.dest) {
+    this.storage = diskStorage({ destination: options.dest })
+  } else {
+    this.storage = memoryStorage()
+  }
+
+  this.limits = options.limits
+  this.preservePath = options.preservePath
+  this.fileFilter = options.fileFilter || allowAll
+}
+
+Multer.prototype._makeMiddleware = function (fields, fileStrategy) {
+  function setup () {
+    var fileFilter = this.fileFilter
+    var filesLeft = Object.create(null)
+
+    fields.forEach(function (field) {
+      if (typeof field.maxCount === 'number') {
+        filesLeft[field.name] = field.maxCount
+      } else {
+        filesLeft[field.name] = Infinity
+      }
+    })
+
+    function wrappedFileFilter (req, file, cb) {
+      if ((filesLeft[file.fieldname] || 0) <= 0) {
+        return cb(new MulterError('LIMIT_UNEXPECTED_FILE', file.fieldname))
+      }
+
+      filesLeft[file.fieldname] -= 1
+      fileFilter(req, file, cb)
+    }
+
+    return {
+      limits: this.limits,
+      preservePath: this.preservePath,
+      storage: this.storage,
+      fileFilter: wrappedFileFilter,
+      fileStrategy: fileStrategy
+    }
+  }
+
+  return makeMiddleware(setup.bind(this))
+}
+
+Multer.prototype.single = function (name) {
+  return this._makeMiddleware([{ name: name, maxCount: 1 }], 'VALUE')
+}
+
+Multer.prototype.array = function (name, maxCount) {
+  return this._makeMiddleware([{ name: name, maxCount: maxCount }], 'ARRAY')
+}
+
+Multer.prototype.fields = function (fields) {
+  return this._makeMiddleware(fields, 'OBJECT')
+}
+
+Multer.prototype.none = function () {
+  return this._makeMiddleware([], 'NONE')
+}
+
+Multer.prototype.any = function () {
+  function setup () {
+    return {
+      limits: this.limits,
+      preservePath: this.preservePath,
+      storage: this.storage,
+      fileFilter: this.fileFilter,
+      fileStrategy: 'ARRAY'
+    }
+  }
+
+  return makeMiddleware(setup.bind(this))
+}
+
+function multer (options) {
+  if (options === undefined) {
+    return new Multer({})
+  }
+
+  if (typeof options === 'object' && options !== null) {
+    return new Multer(options)
+  }
+
+  throw new TypeError('Expected object for argument options')
+}
+
+module.exports = multer
+module.exports.diskStorage = diskStorage
+module.exports.memoryStorage = memoryStorage
+module.exports.MulterError = MulterError
diff --git a/server/node_modules/multer/lib/counter.js b/server/node_modules/multer/lib/counter.js
new file mode 100644
index 0000000..29c410c
--- /dev/null
+++ b/server/node_modules/multer/lib/counter.js
@@ -0,0 +1,28 @@
+var EventEmitter = require('events').EventEmitter
+
+function Counter () {
+  EventEmitter.call(this)
+  this.value = 0
+}
+
+Counter.prototype = Object.create(EventEmitter.prototype)
+
+Counter.prototype.increment = function increment () {
+  this.value++
+}
+
+Counter.prototype.decrement = function decrement () {
+  if (--this.value === 0) this.emit('zero')
+}
+
+Counter.prototype.isZero = function isZero () {
+  return (this.value === 0)
+}
+
+Counter.prototype.onceZero = function onceZero (fn) {
+  if (this.isZero()) return fn()
+
+  this.once('zero', fn)
+}
+
+module.exports = Counter
diff --git a/server/node_modules/multer/lib/file-appender.js b/server/node_modules/multer/lib/file-appender.js
new file mode 100644
index 0000000..1a2c5e7
--- /dev/null
+++ b/server/node_modules/multer/lib/file-appender.js
@@ -0,0 +1,67 @@
+var objectAssign = require('object-assign')
+
+function arrayRemove (arr, item) {
+  var idx = arr.indexOf(item)
+  if (~idx) arr.splice(idx, 1)
+}
+
+function FileAppender (strategy, req) {
+  this.strategy = strategy
+  this.req = req
+
+  switch (strategy) {
+    case 'NONE': break
+    case 'VALUE': break
+    case 'ARRAY': req.files = []; break
+    case 'OBJECT': req.files = Object.create(null); break
+    default: throw new Error('Unknown file strategy: ' + strategy)
+  }
+}
+
+FileAppender.prototype.insertPlaceholder = function (file) {
+  var placeholder = {
+    fieldname: file.fieldname
+  }
+
+  switch (this.strategy) {
+    case 'NONE': break
+    case 'VALUE': break
+    case 'ARRAY': this.req.files.push(placeholder); break
+    case 'OBJECT':
+      if (this.req.files[file.fieldname]) {
+        this.req.files[file.fieldname].push(placeholder)
+      } else {
+        this.req.files[file.fieldname] = [placeholder]
+      }
+      break
+  }
+
+  return placeholder
+}
+
+FileAppender.prototype.removePlaceholder = function (placeholder) {
+  switch (this.strategy) {
+    case 'NONE': break
+    case 'VALUE': break
+    case 'ARRAY': arrayRemove(this.req.files, placeholder); break
+    case 'OBJECT':
+      if (this.req.files[placeholder.fieldname].length === 1) {
+        delete this.req.files[placeholder.fieldname]
+      } else {
+        arrayRemove(this.req.files[placeholder.fieldname], placeholder)
+      }
+      break
+  }
+}
+
+FileAppender.prototype.replacePlaceholder = function (placeholder, file) {
+  if (this.strategy === 'VALUE') {
+    this.req.file = file
+    return
+  }
+
+  delete placeholder.fieldname
+  objectAssign(placeholder, file)
+}
+
+module.exports = FileAppender
diff --git a/server/node_modules/multer/lib/make-middleware.js b/server/node_modules/multer/lib/make-middleware.js
new file mode 100644
index 0000000..cc26414
--- /dev/null
+++ b/server/node_modules/multer/lib/make-middleware.js
@@ -0,0 +1,175 @@
+var is = require('type-is')
+var Busboy = require('busboy')
+var extend = require('xtend')
+var appendField = require('append-field')
+
+var Counter = require('./counter')
+var MulterError = require('./multer-error')
+var FileAppender = require('./file-appender')
+var removeUploadedFiles = require('./remove-uploaded-files')
+
+function makeMiddleware (setup) {
+  return function multerMiddleware (req, res, next) {
+    if (!is(req, ['multipart'])) return next()
+
+    var options = setup()
+
+    var limits = options.limits
+    var storage = options.storage
+    var fileFilter = options.fileFilter
+    var fileStrategy = options.fileStrategy
+    var preservePath = options.preservePath
+
+    req.body = Object.create(null)
+
+    var busboy
+
+    try {
+      busboy = Busboy({ headers: req.headers, limits: limits, preservePath: preservePath })
+    } catch (err) {
+      return next(err)
+    }
+
+    var appender = new FileAppender(fileStrategy, req)
+    var isDone = false
+    var readFinished = false
+    var errorOccured = false
+    var pendingWrites = new Counter()
+    var uploadedFiles = []
+
+    function done (err) {
+      if (isDone) return
+      isDone = true
+      req.unpipe(busboy)
+      process.nextTick(() => {
+        busboy.removeAllListeners()
+      })
+      next(err)
+    }
+
+    function indicateDone () {
+      if (readFinished && pendingWrites.isZero() && !errorOccured) done()
+    }
+
+    function abortWithError (uploadError) {
+      if (errorOccured) return
+      errorOccured = true
+
+      pendingWrites.onceZero(function () {
+        function remove (file, cb) {
+          storage._removeFile(req, file, cb)
+        }
+
+        removeUploadedFiles(uploadedFiles, remove, function (err, storageErrors) {
+          if (err) return done(err)
+
+          uploadError.storageErrors = storageErrors
+          done(uploadError)
+        })
+      })
+    }
+
+    function abortWithCode (code, optionalField) {
+      abortWithError(new MulterError(code, optionalField))
+    }
+
+    // handle text field data
+    busboy.on('field', function (fieldname, value, { nameTruncated, valueTruncated }) {
+      if (fieldname == null) return abortWithCode('MISSING_FIELD_NAME')
+      if (nameTruncated) return abortWithCode('LIMIT_FIELD_KEY')
+      if (valueTruncated) return abortWithCode('LIMIT_FIELD_VALUE', fieldname)
+
+      // Work around bug in Busboy (https://github.com/mscdex/busboy/issues/6)
+      if (limits && Object.prototype.hasOwnProperty.call(limits, 'fieldNameSize')) {
+        if (fieldname.length > limits.fieldNameSize) return abortWithCode('LIMIT_FIELD_KEY')
+      }
+
+      appendField(req.body, fieldname, value)
+    })
+
+    // handle files
+    busboy.on('file', function (fieldname, fileStream, { filename, encoding, mimeType }) {
+      // don't attach to the files object, if there is no file
+      if (!filename) return fileStream.resume()
+
+      // Work around bug in Busboy (https://github.com/mscdex/busboy/issues/6)
+      if (limits && Object.prototype.hasOwnProperty.call(limits, 'fieldNameSize')) {
+        if (fieldname.length > limits.fieldNameSize) return abortWithCode('LIMIT_FIELD_KEY')
+      }
+
+      var file = {
+        fieldname: fieldname,
+        originalname: filename,
+        encoding: encoding,
+        mimetype: mimeType
+      }
+
+      var placeholder = appender.insertPlaceholder(file)
+
+      fileFilter(req, file, function (err, includeFile) {
+        if (err) {
+          appender.removePlaceholder(placeholder)
+          return abortWithError(err)
+        }
+
+        if (!includeFile) {
+          appender.removePlaceholder(placeholder)
+          return fileStream.resume()
+        }
+
+        var aborting = false
+        pendingWrites.increment()
+
+        Object.defineProperty(file, 'stream', {
+          configurable: true,
+          enumerable: false,
+          value: fileStream
+        })
+
+        fileStream.on('error', function (err) {
+          pendingWrites.decrement()
+          abortWithError(err)
+        })
+
+        fileStream.on('limit', function () {
+          aborting = true
+          abortWithCode('LIMIT_FILE_SIZE', fieldname)
+        })
+
+        storage._handleFile(req, file, function (err, info) {
+          if (aborting) {
+            appender.removePlaceholder(placeholder)
+            uploadedFiles.push(extend(file, info))
+            return pendingWrites.decrement()
+          }
+
+          if (err) {
+            appender.removePlaceholder(placeholder)
+            pendingWrites.decrement()
+            return abortWithError(err)
+          }
+
+          var fileInfo = extend(file, info)
+
+          appender.replacePlaceholder(placeholder, fileInfo)
+          uploadedFiles.push(fileInfo)
+          pendingWrites.decrement()
+          indicateDone()
+        })
+      })
+    })
+
+    busboy.on('error', function (err) { abortWithError(err) })
+    busboy.on('partsLimit', function () { abortWithCode('LIMIT_PART_COUNT') })
+    busboy.on('filesLimit', function () { abortWithCode('LIMIT_FILE_COUNT') })
+    busboy.on('fieldsLimit', function () { abortWithCode('LIMIT_FIELD_COUNT') })
+    busboy.on('close', function () {
+      readFinished = true
+      indicateDone()
+    })
+
+    req.pipe(busboy)
+  }
+}
+
+module.exports = makeMiddleware
diff --git a/server/node_modules/multer/lib/multer-error.js b/server/node_modules/multer/lib/multer-error.js
new file mode 100644
index 0000000..d56b00e
--- /dev/null
+++ b/server/node_modules/multer/lib/multer-error.js
@@ -0,0 +1,24 @@
+var util = require('util')
+
+var errorMessages = {
+  LIMIT_PART_COUNT: 'Too many parts',
+  LIMIT_FILE_SIZE: 'File too large',
+  LIMIT_FILE_COUNT: 'Too many files',
+  LIMIT_FIELD_KEY: 'Field name too long',
+  LIMIT_FIELD_VALUE: 'Field value too long',
+  LIMIT_FIELD_COUNT: 'Too many fields',
+  LIMIT_UNEXPECTED_FILE: 'Unexpected field',
+  MISSING_FIELD_NAME: 'Field name missing'
+}
+
+function MulterError (code, field) {
+  Error.captureStackTrace(this, this.constructor)
+  this.name = this.constructor.name
+  this.message = errorMessages[code]
+  this.code = code
+  if (field) this.field = field
+}
+
+util.inherits(MulterError, Error)
+
+module.exports = MulterError
diff --git a/server/node_modules/multer/lib/remove-uploaded-files.js b/server/node_modules/multer/lib/remove-uploaded-files.js
new file mode 100644
index 0000000..f0b16ea
--- /dev/null
+++ b/server/node_modules/multer/lib/remove-uploaded-files.js
@@ -0,0 +1,28 @@
+function removeUploadedFiles (uploadedFiles, remove, cb) {
+  var length = uploadedFiles.length
+  var errors = []
+
+  if (length === 0) return cb(null, errors)
+
+  function handleFile (idx) {
+    var file = uploadedFiles[idx]
+
+    remove(file, function (err) {
+      if (err) {
+        err.file = file
+        err.field = file.fieldname
+        errors.push(err)
+      }
+
+      if (idx < length - 1) {
+        handleFile(idx + 1)
+      } else {
+        cb(null, errors)
+      }
+    })
+  }
+
+  handleFile(0)
+}
+
+module.exports = removeUploadedFiles
diff --git a/server/node_modules/multer/package.json b/server/node_modules/multer/package.json
new file mode 100644
index 0000000..32507d8
--- /dev/null
+++ b/server/node_modules/multer/package.json
@@ -0,0 +1,52 @@
+{
+  "name": "multer",
+  "description": "Middleware for handling `multipart/form-data`.",
+  "version": "1.4.5-lts.2",
+  "contributors": [
+    "Hage Yaapa <captain@hacksparrow.com> (http://www.hacksparrow.com)",
+    "Jaret Pfluger <https://github.com/jpfluger>",
+    "Linus Unnebäck <linus@folkdatorn.se>"
+  ],
+  "license": "MIT",
+  "repository": "expressjs/multer",
+  "keywords": [
+    "form",
+    "post",
+    "multipart",
+    "form-data",
+    "formdata",
+    "express",
+    "middleware"
+  ],
+  "dependencies": {
+    "append-field": "^1.0.0",
+    "busboy": "^1.0.0",
+    "concat-stream": "^1.5.2",
+    "mkdirp": "^0.5.4",
+    "object-assign": "^4.1.1",
+    "type-is": "^1.6.4",
+    "xtend": "^4.0.0"
+  },
+  "devDependencies": {
+    "deep-equal": "^2.0.3",
+    "express": "^4.13.1",
+    "form-data": "^1.0.0-rc1",
+    "fs-temp": "^1.1.2",
+    "mocha": "^3.5.3",
+    "rimraf": "^2.4.1",
+    "standard": "^14.3.3",
+    "testdata-w3c-json-form": "^1.0.0"
+  },
+  "engines": {
+    "node": ">= 6.0.0"
+  },
+  "files": [
+    "LICENSE",
+    "index.js",
+    "storage/",
+    "lib/"
+  ],
+  "scripts": {
+    "test": "standard && mocha"
+  }
+}
diff --git a/server/node_modules/multer/storage/disk.js b/server/node_modules/multer/storage/disk.js
new file mode 100644
index 0000000..2f77c9f
--- /dev/null
+++ b/server/node_modules/multer/storage/disk.js
@@ -0,0 +1,66 @@
+var fs = require('fs')
+var os = require('os')
+var path = require('path')
+var crypto = require('crypto')
+var mkdirp = require('mkdirp')
+
+function getFilename (req, file, cb) {
+  crypto.randomBytes(16, function (err, raw) {
+    cb(err, err ? undefined : raw.toString('hex'))
+  })
+}
+
+function getDestination (req, file, cb) {
+  cb(null, os.tmpdir())
+}
+
+function DiskStorage (opts) {
+  this.getFilename = (opts.filename || getFilename)
+
+  if (typeof opts.destination === 'string') {
+    mkdirp.sync(opts.destination)
+    this.getDestination = function ($0, $1, cb) { cb(null, opts.destination) }
+  } else {
+    this.getDestination = (opts.destination || getDestination)
+  }
+}
+
+DiskStorage.prototype._handleFile = function _handleFile (req, file, cb) {
+  var that = this
+
+  that.getDestination(req, file, function (err, destination) {
+    if (err) return cb(err)
+
+    that.getFilename(req, file, function (err, filename) {
+      if (err) return cb(err)
+
+      var finalPath = path.join(destination, filename)
+      var outStream = fs.createWriteStream(finalPath)
+
+      file.stream.pipe(outStream)
+      outStream.on('error', cb)
+      outStream.on('finish', function () {
+        cb(null, {
+          destination: destination,
+          filename: filename,
+          path: finalPath,
+          size: outStream.bytesWritten
+        })
+      })
+    })
+  })
+}
+
+DiskStorage.prototype._removeFile = function _removeFile (req, file, cb) {
+  var path = file.path
+
+  delete file.destination
+  delete file.filename
+  delete file.path
+
+  fs.unlink(path, cb)
+}
+
+module.exports = function (opts) {
+  return new DiskStorage(opts)
+}
diff --git a/server/node_modules/multer/storage/memory.js b/server/node_modules/multer/storage/memory.js
new file mode 100644
index 0000000..f953ded
--- /dev/null
+++ b/server/node_modules/multer/storage/memory.js
@@ -0,0 +1,21 @@
+var concat = require('concat-stream')
+
+function MemoryStorage (opts) {}
+
+MemoryStorage.prototype._handleFile = function _handleFile (req, file, cb) {
+  file.stream.pipe(concat({ encoding: 'buffer' }, function (data) {
+    cb(null, {
+      buffer: data,
+      size: data.length
+    })
+  }))
+}
+
+MemoryStorage.prototype._removeFile = function _removeFile (req, file, cb) {
+  delete file.buffer
+  cb(null)
+}
+
+module.exports = function (opts) {
+  return new MemoryStorage(opts)
+}
diff --git a/server/node_modules/napi-build-utils/.github/workflows/run-npm-tests.yml b/server/node_modules/napi-build-utils/.github/workflows/run-npm-tests.yml
new file mode 100644
index 0000000..3298868
--- /dev/null
+++ b/server/node_modules/napi-build-utils/.github/workflows/run-npm-tests.yml
@@ -0,0 +1,31 @@
+name: Run npm Tests
+
+on:
+  workflow_dispatch:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [22, 23]
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    - name: Set up Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v3
+      with:
+        node-version: ${{ matrix.node-version }}
+
+    - name: Install dependencies
+      run: npm install
+
+    - name: Run tests
+      run: npm test
\ No newline at end of file
diff --git a/server/node_modules/napi-build-utils/LICENSE b/server/node_modules/napi-build-utils/LICENSE
new file mode 100644
index 0000000..8e0248a
--- /dev/null
+++ b/server/node_modules/napi-build-utils/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018 inspiredware
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/napi-build-utils/README.md b/server/node_modules/napi-build-utils/README.md
new file mode 100644
index 0000000..7c29b68
--- /dev/null
+++ b/server/node_modules/napi-build-utils/README.md
@@ -0,0 +1,52 @@
+# napi-build-utils
+
+[![npm](https://img.shields.io/npm/v/napi-build-utils.svg)](https://www.npmjs.com/package/napi-build-utils)
+![Node version](https://img.shields.io/node/v/prebuild.svg)
+![Build Status](https://github.com/inspiredware/napi-build-utils/actions/workflows/run-npm-tests.yml/badge.svg)
+[![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg)](http://standardjs.com/)
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
+
+A set of utilities to assist developers of tools that build [Node-API](https://nodejs.org/api/n-api.html#n_api_n_api) native add-ons.
+
+## Background
+
+This module is targeted to developers creating tools that build Node-API native add-ons.
+
+It implements a set of functions that aid in determining the Node-API version supported by the currently running Node instance and the set of Node-API versions against which the Node-API native add-on is designed to be built. Other functions determine whether a particular Node-API version can be built and can issue console warnings for unsupported Node-API versions.
+
+Unlike the modules this code is designed to facilitate building, this module is written entirely in JavaScript.
+
+## Quick start
+
+```bash
+npm install napi-build-utils
+```
+
+The module exports a set of functions documented [here](./index.md). For example:
+
+```javascript
+var napiBuildUtils = require('napi-build-utils');
+var napiVersion = napiBuildUtils.getNapiVersion(); // Node-API version supported by Node, or undefined.
+```
+
+## Declaring supported Node-API versions
+
+Native modules that are designed to work with [Node-API](https://nodejs.org/api/n-api.html#n_api_n_api) must explicitly declare the Node-API version(s) against which they are coded to build. This is accomplished by including a `binary.napi_versions` property in the module's `package.json` file. For example:
+
+```json
+"binary": {
+  "napi_versions": [2,3]
+}
+```
+
+In the absence of a need to compile against a specific Node-API version, the value `3` is a good choice as this is the Node-API version that was supported when Node-API left experimental status.
+
+Modules that are built against a specific Node-API version will continue to operate indefinitely, even as later versions of Node-API are introduced.
+
+## History
+
+**v2.0.0** This version was introduced to address a limitation when the Node-API version reached `10` in NodeJS `v23.6.0`. There was no change in the API, but a SemVer bump to `2.0.0` was made out of an abundance of caution.
+
+## Support
+
+If you run into problems or limitations, please file an issue and we'll take a look. Pull requests are also welcome.
diff --git a/server/node_modules/napi-build-utils/index.js b/server/node_modules/napi-build-utils/index.js
new file mode 100644
index 0000000..d143d5d
--- /dev/null
+++ b/server/node_modules/napi-build-utils/index.js
@@ -0,0 +1,214 @@
+'use strict'
+// Copyright (c) 2018 inspiredware
+
+var path = require('path')
+var pkg = require(path.resolve('package.json'))
+
+var versionArray = process.version
+  .substr(1)
+  .replace(/-.*$/, '')
+  .split('.')
+  .map(function (item) {
+    return +item
+  })
+
+/**
+ *
+ * A set of utilities to assist developers of tools that build
+ * [N-API](https://nodejs.org/api/n-api.html#n_api_n_api) native add-ons.
+ *
+ * The main repository can be found
+ * [here](https://github.com/inspiredware/napi-build-utils#napi-build-utils).
+ *
+ * @module napi-build-utils
+ */
+
+/**
+ * Implements a consistent name of `napi` for N-API runtimes.
+ *
+ * @param {string} runtime The runtime string.
+ * @returns {boolean}
+ */
+exports.isNapiRuntime = function (runtime) {
+  return runtime === 'napi'
+}
+
+/**
+ * Determines whether the specified N-API version is supported
+ * by both the currently running Node instance and the package.
+ *
+ * @param {string} napiVersion The N-API version to check.
+ * @returns {boolean}
+ */
+exports.isSupportedVersion = function (napiVersion) {
+  var version = parseInt(napiVersion, 10)
+  return version <= exports.getNapiVersion() && exports.packageSupportsVersion(version)
+}
+
+/**
+ * Determines whether the specified N-API version is supported by the package.
+ * The N-API version must be present in the `package.json`
+ * `binary.napi_versions` array.
+ *
+ * @param {number} napiVersion The N-API version to check.
+ * @returns {boolean}
+ * @private
+ */
+exports.packageSupportsVersion = function (napiVersion) {
+  if (pkg.binary && pkg.binary.napi_versions &&
+      pkg.binary.napi_versions instanceof Array) { // integer array
+    for (var i = 0; i < pkg.binary.napi_versions.length; i++) {
+      if (pkg.binary.napi_versions[i] === napiVersion) return true
+    };
+  };
+  return false
+}
+
+/**
+ * Issues a warning to the supplied log if the N-API version is not supported
+ * by the current Node instance or if the N-API version is not supported
+ * by the package.
+ *
+ * @param {string} napiVersion The N-API version to check.
+ * @param {Object} log The log object to which the warnings are to be issued.
+ * Must implement the `warn` method.
+ */
+exports.logUnsupportedVersion = function (napiVersion, log) {
+  if (!exports.isSupportedVersion(napiVersion)) {
+    if (exports.packageSupportsVersion(napiVersion)) {
+      log.warn('This Node instance does not support N-API version ' + napiVersion)
+    } else {
+      log.warn('This package does not support N-API version ' + napiVersion)
+    }
+  }
+}
+
+/**
+ * Issues warnings to the supplied log for those N-API versions not supported
+ * by the N-API runtime or the package.
+ *
+ * Note that this function is specific to the
+ * [`prebuild`](https://github.com/prebuild/prebuild#prebuild) package.
+ *
+ * `target` is the list of targets to be built and is determined in one of
+ * three ways from the command line arguments:
+ * (1) `--target` specifies a specific target to build.
+ * (2) `--all` specifies all N-API versions supported by the package.
+ * (3) Neither of these specifies to build the single "best version available."
+ *
+ * `prebuild` is an array of objects in the form `{runtime: 'napi', target: '2'}`.
+ * The array contains the list of N-API versions that are supported by both the
+ * package being built and the currently running Node instance.
+ *
+ * The objective of this function is to issue a warning for those items that appear
+ * in the `target` argument but not in the `prebuild` argument.
+ * If a specific target is supported by the package (`packageSupportsVersion`) but
+ * but note in `prebuild`, the assumption is that the target is not supported by
+ * Node.
+ *
+ * @param {(Array<string>|string)} target The N-API version(s) to check. Target is
+ * @param {Array<Object>} prebuild A config object created by the `prebuild` package.
+ * @param {Object} log The log object to which the warnings are to be issued.
+ * Must implement the `warn` method.
+ * @private
+ */
+exports.logMissingNapiVersions = function (target, prebuild, log) {
+  if (exports.getNapiBuildVersions()) {
+    var targets = [].concat(target)
+    targets.forEach(function (napiVersion) {
+      if (!prebuildExists(prebuild, napiVersion)) {
+        if (exports.packageSupportsVersion(parseInt(napiVersion, 10))) {
+          log.warn('This Node instance does not support N-API version ' + napiVersion)
+        } else {
+          log.warn('This package does not support N-API version ' + napiVersion)
+        }
+      }
+    })
+  } else {
+    log.error('Builds with runtime \'napi\' require a binary.napi_versions ' +
+              'property on the package.json file')
+  }
+}
+
+/**
+ * Determines whether the specified N-API version exists in the prebuild
+ * configuration object.
+ *
+ * Note that this function is specific to the `prebuild` and `prebuild-install`
+ * packages.
+ *
+ * @param {Object} prebuild A config object created by the `prebuild` package.
+ * @param {string} napiVersion The N-APi version to be checked.
+ * @return {boolean}
+ * @private
+ */
+var prebuildExists = function (prebuild, napiVersion) {
+  if (prebuild) {
+    for (var i = 0; i < prebuild.length; i++) {
+      if (prebuild[i].target === napiVersion) return true
+    }
+  }
+  return false
+}
+
+/**
+ * Returns the best N-API version to build given the highest N-API
+ * version supported by the current Node instance and the N-API versions
+ * supported by the package, or undefined if a suitable N-API version
+ * cannot be determined.
+ *
+ * The best build version is the greatest N-API version supported by
+ * the package that is less than or equal to the highest N-API version
+ * supported by the current Node instance.
+ *
+ * @returns {number|undefined}
+ */
+exports.getBestNapiBuildVersion = function () {
+  var bestNapiBuildVersion = 0
+  var napiBuildVersions = exports.getNapiBuildVersions(pkg) // array of integer strings
+  if (napiBuildVersions) {
+    var ourNapiVersion = exports.getNapiVersion()
+    napiBuildVersions.forEach(function (napiBuildVersionStr) {
+      var napiBuildVersion = parseInt(napiBuildVersionStr, 10)
+      if (napiBuildVersion > bestNapiBuildVersion &&
+        napiBuildVersion <= ourNapiVersion) {
+        bestNapiBuildVersion = napiBuildVersion
+      }
+    })
+  }
+  return bestNapiBuildVersion === 0 ? undefined : bestNapiBuildVersion
+}
+
+/**
+ * Returns an array of N-API versions supported by the package.
+ *
+ * @returns {Array<string>|undefined}
+ */
+exports.getNapiBuildVersions = function () {
+  var napiBuildVersions = []
+  // remove duplicates, convert to text
+  if (pkg.binary && pkg.binary.napi_versions) {
+    pkg.binary.napi_versions.forEach(function (napiVersion) {
+      var duplicated = napiBuildVersions.indexOf('' + napiVersion) !== -1
+      if (!duplicated) {
+        napiBuildVersions.push('' + napiVersion)
+      }
+    })
+  }
+  return napiBuildVersions.length ? napiBuildVersions : undefined
+}
+
+/**
+ * Returns the highest N-API version supported by the current node instance
+ * or undefined if N-API is not supported.
+ *
+ * @returns {string|undefined}
+ */
+exports.getNapiVersion = function () {
+  var version = process.versions.napi // integer string, can be undefined
+  if (!version) { // this code should never need to be updated
+    if (versionArray[0] === 9 && versionArray[1] >= 3) version = '2' // 9.3.0+
+    else if (versionArray[0] === 8) version = '1' // 8.0.0+
+  }
+  return version
+}
diff --git a/server/node_modules/napi-build-utils/index.md b/server/node_modules/napi-build-utils/index.md
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/napi-build-utils/package.json b/server/node_modules/napi-build-utils/package.json
new file mode 100644
index 0000000..ad15183
--- /dev/null
+++ b/server/node_modules/napi-build-utils/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "napi-build-utils",
+  "version": "2.0.0",
+  "description": "A set of utilities to assist developers of tools that build N-API native add-ons",
+  "main": "index.js",
+  "scripts": {
+    "doc": "jsdoc2md index.js >index.md",
+    "test": "mocha test/ && npm run lint",
+    "lint": "standard",
+    "prepublishOnly": "npm run test"
+  },
+  "keywords": [
+    "n-api",
+    "prebuild",
+    "prebuild-install"
+  ],
+  "author": "Jim Schlight",
+  "license": "MIT",
+  "homepage": "https://github.com/inspiredware/napi-build-utils#readme",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/inspiredware/napi-build-utils.git"
+  },
+  "bugs": {
+    "url": "https://github.com/inspiredware/napi-build-utils/issues"
+  },
+  "devDependencies": {
+    "chai": "^4.1.2",
+    "jsdoc-to-markdown": "^4.0.1",
+    "mocha": "^5.2.0",
+    "standard": "^12.0.1"
+  },
+  "binary": {
+    "note": "napi-build-tools is not an N-API module. This entry is for unit testing.",
+    "napi_versions": [
+      2,
+      2,
+      3,
+      10
+    ]
+  }
+}
diff --git a/server/node_modules/negotiator/HISTORY.md b/server/node_modules/negotiator/HISTORY.md
new file mode 100644
index 0000000..a9a5449
--- /dev/null
+++ b/server/node_modules/negotiator/HISTORY.md
@@ -0,0 +1,108 @@
+0.6.3 / 2022-01-22
+==================
+
+  * Revert "Lazy-load modules from main entry point"
+
+0.6.2 / 2019-04-29
+==================
+
+  * Fix sorting charset, encoding, and language with extra parameters
+
+0.6.1 / 2016-05-02
+==================
+
+  * perf: improve `Accept` parsing speed
+  * perf: improve `Accept-Charset` parsing speed
+  * perf: improve `Accept-Encoding` parsing speed
+  * perf: improve `Accept-Language` parsing speed
+
+0.6.0 / 2015-09-29
+==================
+
+  * Fix including type extensions in parameters in `Accept` parsing
+  * Fix parsing `Accept` parameters with quoted equals
+  * Fix parsing `Accept` parameters with quoted semicolons
+  * Lazy-load modules from main entry point
+  * perf: delay type concatenation until needed
+  * perf: enable strict mode
+  * perf: hoist regular expressions
+  * perf: remove closures getting spec properties
+  * perf: remove a closure from media type parsing
+  * perf: remove property delete from media type parsing
+
+0.5.3 / 2015-05-10
+==================
+
+  * Fix media type parameter matching to be case-insensitive
+
+0.5.2 / 2015-05-06
+==================
+
+  * Fix comparing media types with quoted values
+  * Fix splitting media types with quoted commas
+
+0.5.1 / 2015-02-14
+==================
+
+  * Fix preference sorting to be stable for long acceptable lists
+
+0.5.0 / 2014-12-18
+==================
+
+  * Fix list return order when large accepted list
+  * Fix missing identity encoding when q=0 exists
+  * Remove dynamic building of Negotiator class
+
+0.4.9 / 2014-10-14
+==================
+
+  * Fix error when media type has invalid parameter
+
+0.4.8 / 2014-09-28
+==================
+
+  * Fix all negotiations to be case-insensitive
+  * Stable sort preferences of same quality according to client order
+  * Support Node.js 0.6
+
+0.4.7 / 2014-06-24
+==================
+
+  * Handle invalid provided languages
+  * Handle invalid provided media types
+
+0.4.6 / 2014-06-11
+==================
+
+  *  Order by specificity when quality is the same
+
+0.4.5 / 2014-05-29
+==================
+
+  * Fix regression in empty header handling
+
+0.4.4 / 2014-05-29
+==================
+
+  * Fix behaviors when headers are not present
+
+0.4.3 / 2014-04-16
+==================
+
+  * Handle slashes on media params correctly
+
+0.4.2 / 2014-02-28
+==================
+
+  * Fix media type sorting
+  * Handle media types params strictly
+
+0.4.1 / 2014-01-16
+==================
+
+  * Use most specific matches
+
+0.4.0 / 2014-01-09
+==================
+
+  * Remove preferred prefix from methods
diff --git a/server/node_modules/negotiator/LICENSE b/server/node_modules/negotiator/LICENSE
new file mode 100644
index 0000000..ea6b9e2
--- /dev/null
+++ b/server/node_modules/negotiator/LICENSE
@@ -0,0 +1,24 @@
+(The MIT License)
+
+Copyright (c) 2012-2014 Federico Romero
+Copyright (c) 2012-2014 Isaac Z. Schlueter
+Copyright (c) 2014-2015 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/negotiator/README.md b/server/node_modules/negotiator/README.md
new file mode 100644
index 0000000..82915e5
--- /dev/null
+++ b/server/node_modules/negotiator/README.md
@@ -0,0 +1,203 @@
+# negotiator
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][github-actions-ci-image]][github-actions-ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+An HTTP content negotiator for Node.js
+
+## Installation
+
+```sh
+$ npm install negotiator
+```
+
+## API
+
+```js
+var Negotiator = require('negotiator')
+```
+
+### Accept Negotiation
+
+```js
+availableMediaTypes = ['text/html', 'text/plain', 'application/json']
+
+// The negotiator constructor receives a request object
+negotiator = new Negotiator(request)
+
+// Let's say Accept header is 'text/html, application/*;q=0.2, image/jpeg;q=0.8'
+
+negotiator.mediaTypes()
+// -> ['text/html', 'image/jpeg', 'application/*']
+
+negotiator.mediaTypes(availableMediaTypes)
+// -> ['text/html', 'application/json']
+
+negotiator.mediaType(availableMediaTypes)
+// -> 'text/html'
+```
+
+You can check a working example at `examples/accept.js`.
+
+#### Methods
+
+##### mediaType()
+
+Returns the most preferred media type from the client.
+
+##### mediaType(availableMediaType)
+
+Returns the most preferred media type from a list of available media types.
+
+##### mediaTypes()
+
+Returns an array of preferred media types ordered by the client preference.
+
+##### mediaTypes(availableMediaTypes)
+
+Returns an array of preferred media types ordered by priority from a list of
+available media types.
+
+### Accept-Language Negotiation
+
+```js
+negotiator = new Negotiator(request)
+
+availableLanguages = ['en', 'es', 'fr']
+
+// Let's say Accept-Language header is 'en;q=0.8, es, pt'
+
+negotiator.languages()
+// -> ['es', 'pt', 'en']
+
+negotiator.languages(availableLanguages)
+// -> ['es', 'en']
+
+language = negotiator.language(availableLanguages)
+// -> 'es'
+```
+
+You can check a working example at `examples/language.js`.
+
+#### Methods
+
+##### language()
+
+Returns the most preferred language from the client.
+
+##### language(availableLanguages)
+
+Returns the most preferred language from a list of available languages.
+
+##### languages()
+
+Returns an array of preferred languages ordered by the client preference.
+
+##### languages(availableLanguages)
+
+Returns an array of preferred languages ordered by priority from a list of
+available languages.
+
+### Accept-Charset Negotiation
+
+```js
+availableCharsets = ['utf-8', 'iso-8859-1', 'iso-8859-5']
+
+negotiator = new Negotiator(request)
+
+// Let's say Accept-Charset header is 'utf-8, iso-8859-1;q=0.8, utf-7;q=0.2'
+
+negotiator.charsets()
+// -> ['utf-8', 'iso-8859-1', 'utf-7']
+
+negotiator.charsets(availableCharsets)
+// -> ['utf-8', 'iso-8859-1']
+
+negotiator.charset(availableCharsets)
+// -> 'utf-8'
+```
+
+You can check a working example at `examples/charset.js`.
+
+#### Methods
+
+##### charset()
+
+Returns the most preferred charset from the client.
+
+##### charset(availableCharsets)
+
+Returns the most preferred charset from a list of available charsets.
+
+##### charsets()
+
+Returns an array of preferred charsets ordered by the client preference.
+
+##### charsets(availableCharsets)
+
+Returns an array of preferred charsets ordered by priority from a list of
+available charsets.
+
+### Accept-Encoding Negotiation
+
+```js
+availableEncodings = ['identity', 'gzip']
+
+negotiator = new Negotiator(request)
+
+// Let's say Accept-Encoding header is 'gzip, compress;q=0.2, identity;q=0.5'
+
+negotiator.encodings()
+// -> ['gzip', 'identity', 'compress']
+
+negotiator.encodings(availableEncodings)
+// -> ['gzip', 'identity']
+
+negotiator.encoding(availableEncodings)
+// -> 'gzip'
+```
+
+You can check a working example at `examples/encoding.js`.
+
+#### Methods
+
+##### encoding()
+
+Returns the most preferred encoding from the client.
+
+##### encoding(availableEncodings)
+
+Returns the most preferred encoding from a list of available encodings.
+
+##### encodings()
+
+Returns an array of preferred encodings ordered by the client preference.
+
+##### encodings(availableEncodings)
+
+Returns an array of preferred encodings ordered by priority from a list of
+available encodings.
+
+## See Also
+
+The [accepts](https://npmjs.org/package/accepts#readme) module builds on
+this module and provides an alternative interface, mime type validation,
+and more.
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/negotiator.svg
+[npm-url]: https://npmjs.org/package/negotiator
+[node-version-image]: https://img.shields.io/node/v/negotiator.svg
+[node-version-url]: https://nodejs.org/en/download/
+[coveralls-image]: https://img.shields.io/coveralls/jshttp/negotiator/master.svg
+[coveralls-url]: https://coveralls.io/r/jshttp/negotiator?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/negotiator.svg
+[downloads-url]: https://npmjs.org/package/negotiator
+[github-actions-ci-image]: https://img.shields.io/github/workflow/status/jshttp/negotiator/ci/master?label=ci
+[github-actions-ci-url]: https://github.com/jshttp/negotiator/actions/workflows/ci.yml
diff --git a/server/node_modules/negotiator/index.js b/server/node_modules/negotiator/index.js
new file mode 100644
index 0000000..4788264
--- /dev/null
+++ b/server/node_modules/negotiator/index.js
@@ -0,0 +1,82 @@
+/*!
+ * negotiator
+ * Copyright(c) 2012 Federico Romero
+ * Copyright(c) 2012-2014 Isaac Z. Schlueter
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+var preferredCharsets = require('./lib/charset')
+var preferredEncodings = require('./lib/encoding')
+var preferredLanguages = require('./lib/language')
+var preferredMediaTypes = require('./lib/mediaType')
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = Negotiator;
+module.exports.Negotiator = Negotiator;
+
+/**
+ * Create a Negotiator instance from a request.
+ * @param {object} request
+ * @public
+ */
+
+function Negotiator(request) {
+  if (!(this instanceof Negotiator)) {
+    return new Negotiator(request);
+  }
+
+  this.request = request;
+}
+
+Negotiator.prototype.charset = function charset(available) {
+  var set = this.charsets(available);
+  return set && set[0];
+};
+
+Negotiator.prototype.charsets = function charsets(available) {
+  return preferredCharsets(this.request.headers['accept-charset'], available);
+};
+
+Negotiator.prototype.encoding = function encoding(available) {
+  var set = this.encodings(available);
+  return set && set[0];
+};
+
+Negotiator.prototype.encodings = function encodings(available) {
+  return preferredEncodings(this.request.headers['accept-encoding'], available);
+};
+
+Negotiator.prototype.language = function language(available) {
+  var set = this.languages(available);
+  return set && set[0];
+};
+
+Negotiator.prototype.languages = function languages(available) {
+  return preferredLanguages(this.request.headers['accept-language'], available);
+};
+
+Negotiator.prototype.mediaType = function mediaType(available) {
+  var set = this.mediaTypes(available);
+  return set && set[0];
+};
+
+Negotiator.prototype.mediaTypes = function mediaTypes(available) {
+  return preferredMediaTypes(this.request.headers.accept, available);
+};
+
+// Backwards compatibility
+Negotiator.prototype.preferredCharset = Negotiator.prototype.charset;
+Negotiator.prototype.preferredCharsets = Negotiator.prototype.charsets;
+Negotiator.prototype.preferredEncoding = Negotiator.prototype.encoding;
+Negotiator.prototype.preferredEncodings = Negotiator.prototype.encodings;
+Negotiator.prototype.preferredLanguage = Negotiator.prototype.language;
+Negotiator.prototype.preferredLanguages = Negotiator.prototype.languages;
+Negotiator.prototype.preferredMediaType = Negotiator.prototype.mediaType;
+Negotiator.prototype.preferredMediaTypes = Negotiator.prototype.mediaTypes;
diff --git a/server/node_modules/negotiator/lib/charset.js b/server/node_modules/negotiator/lib/charset.js
new file mode 100644
index 0000000..cdd0148
--- /dev/null
+++ b/server/node_modules/negotiator/lib/charset.js
@@ -0,0 +1,169 @@
+/**
+ * negotiator
+ * Copyright(c) 2012 Isaac Z. Schlueter
+ * Copyright(c) 2014 Federico Romero
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = preferredCharsets;
+module.exports.preferredCharsets = preferredCharsets;
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var simpleCharsetRegExp = /^\s*([^\s;]+)\s*(?:;(.*))?$/;
+
+/**
+ * Parse the Accept-Charset header.
+ * @private
+ */
+
+function parseAcceptCharset(accept) {
+  var accepts = accept.split(',');
+
+  for (var i = 0, j = 0; i < accepts.length; i++) {
+    var charset = parseCharset(accepts[i].trim(), i);
+
+    if (charset) {
+      accepts[j++] = charset;
+    }
+  }
+
+  // trim accepts
+  accepts.length = j;
+
+  return accepts;
+}
+
+/**
+ * Parse a charset from the Accept-Charset header.
+ * @private
+ */
+
+function parseCharset(str, i) {
+  var match = simpleCharsetRegExp.exec(str);
+  if (!match) return null;
+
+  var charset = match[1];
+  var q = 1;
+  if (match[2]) {
+    var params = match[2].split(';')
+    for (var j = 0; j < params.length; j++) {
+      var p = params[j].trim().split('=');
+      if (p[0] === 'q') {
+        q = parseFloat(p[1]);
+        break;
+      }
+    }
+  }
+
+  return {
+    charset: charset,
+    q: q,
+    i: i
+  };
+}
+
+/**
+ * Get the priority of a charset.
+ * @private
+ */
+
+function getCharsetPriority(charset, accepted, index) {
+  var priority = {o: -1, q: 0, s: 0};
+
+  for (var i = 0; i < accepted.length; i++) {
+    var spec = specify(charset, accepted[i], index);
+
+    if (spec && (priority.s - spec.s || priority.q - spec.q || priority.o - spec.o) < 0) {
+      priority = spec;
+    }
+  }
+
+  return priority;
+}
+
+/**
+ * Get the specificity of the charset.
+ * @private
+ */
+
+function specify(charset, spec, index) {
+  var s = 0;
+  if(spec.charset.toLowerCase() === charset.toLowerCase()){
+    s |= 1;
+  } else if (spec.charset !== '*' ) {
+    return null
+  }
+
+  return {
+    i: index,
+    o: spec.i,
+    q: spec.q,
+    s: s
+  }
+}
+
+/**
+ * Get the preferred charsets from an Accept-Charset header.
+ * @public
+ */
+
+function preferredCharsets(accept, provided) {
+  // RFC 2616 sec 14.2: no header = *
+  var accepts = parseAcceptCharset(accept === undefined ? '*' : accept || '');
+
+  if (!provided) {
+    // sorted list of all charsets
+    return accepts
+      .filter(isQuality)
+      .sort(compareSpecs)
+      .map(getFullCharset);
+  }
+
+  var priorities = provided.map(function getPriority(type, index) {
+    return getCharsetPriority(type, accepts, index);
+  });
+
+  // sorted list of accepted charsets
+  return priorities.filter(isQuality).sort(compareSpecs).map(function getCharset(priority) {
+    return provided[priorities.indexOf(priority)];
+  });
+}
+
+/**
+ * Compare two specs.
+ * @private
+ */
+
+function compareSpecs(a, b) {
+  return (b.q - a.q) || (b.s - a.s) || (a.o - b.o) || (a.i - b.i) || 0;
+}
+
+/**
+ * Get full charset string.
+ * @private
+ */
+
+function getFullCharset(spec) {
+  return spec.charset;
+}
+
+/**
+ * Check if a spec has any quality.
+ * @private
+ */
+
+function isQuality(spec) {
+  return spec.q > 0;
+}
diff --git a/server/node_modules/negotiator/lib/encoding.js b/server/node_modules/negotiator/lib/encoding.js
new file mode 100644
index 0000000..8432cd7
--- /dev/null
+++ b/server/node_modules/negotiator/lib/encoding.js
@@ -0,0 +1,184 @@
+/**
+ * negotiator
+ * Copyright(c) 2012 Isaac Z. Schlueter
+ * Copyright(c) 2014 Federico Romero
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = preferredEncodings;
+module.exports.preferredEncodings = preferredEncodings;
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var simpleEncodingRegExp = /^\s*([^\s;]+)\s*(?:;(.*))?$/;
+
+/**
+ * Parse the Accept-Encoding header.
+ * @private
+ */
+
+function parseAcceptEncoding(accept) {
+  var accepts = accept.split(',');
+  var hasIdentity = false;
+  var minQuality = 1;
+
+  for (var i = 0, j = 0; i < accepts.length; i++) {
+    var encoding = parseEncoding(accepts[i].trim(), i);
+
+    if (encoding) {
+      accepts[j++] = encoding;
+      hasIdentity = hasIdentity || specify('identity', encoding);
+      minQuality = Math.min(minQuality, encoding.q || 1);
+    }
+  }
+
+  if (!hasIdentity) {
+    /*
+     * If identity doesn't explicitly appear in the accept-encoding header,
+     * it's added to the list of acceptable encoding with the lowest q
+     */
+    accepts[j++] = {
+      encoding: 'identity',
+      q: minQuality,
+      i: i
+    };
+  }
+
+  // trim accepts
+  accepts.length = j;
+
+  return accepts;
+}
+
+/**
+ * Parse an encoding from the Accept-Encoding header.
+ * @private
+ */
+
+function parseEncoding(str, i) {
+  var match = simpleEncodingRegExp.exec(str);
+  if (!match) return null;
+
+  var encoding = match[1];
+  var q = 1;
+  if (match[2]) {
+    var params = match[2].split(';');
+    for (var j = 0; j < params.length; j++) {
+      var p = params[j].trim().split('=');
+      if (p[0] === 'q') {
+        q = parseFloat(p[1]);
+        break;
+      }
+    }
+  }
+
+  return {
+    encoding: encoding,
+    q: q,
+    i: i
+  };
+}
+
+/**
+ * Get the priority of an encoding.
+ * @private
+ */
+
+function getEncodingPriority(encoding, accepted, index) {
+  var priority = {o: -1, q: 0, s: 0};
+
+  for (var i = 0; i < accepted.length; i++) {
+    var spec = specify(encoding, accepted[i], index);
+
+    if (spec && (priority.s - spec.s || priority.q - spec.q || priority.o - spec.o) < 0) {
+      priority = spec;
+    }
+  }
+
+  return priority;
+}
+
+/**
+ * Get the specificity of the encoding.
+ * @private
+ */
+
+function specify(encoding, spec, index) {
+  var s = 0;
+  if(spec.encoding.toLowerCase() === encoding.toLowerCase()){
+    s |= 1;
+  } else if (spec.encoding !== '*' ) {
+    return null
+  }
+
+  return {
+    i: index,
+    o: spec.i,
+    q: spec.q,
+    s: s
+  }
+};
+
+/**
+ * Get the preferred encodings from an Accept-Encoding header.
+ * @public
+ */
+
+function preferredEncodings(accept, provided) {
+  var accepts = parseAcceptEncoding(accept || '');
+
+  if (!provided) {
+    // sorted list of all encodings
+    return accepts
+      .filter(isQuality)
+      .sort(compareSpecs)
+      .map(getFullEncoding);
+  }
+
+  var priorities = provided.map(function getPriority(type, index) {
+    return getEncodingPriority(type, accepts, index);
+  });
+
+  // sorted list of accepted encodings
+  return priorities.filter(isQuality).sort(compareSpecs).map(function getEncoding(priority) {
+    return provided[priorities.indexOf(priority)];
+  });
+}
+
+/**
+ * Compare two specs.
+ * @private
+ */
+
+function compareSpecs(a, b) {
+  return (b.q - a.q) || (b.s - a.s) || (a.o - b.o) || (a.i - b.i) || 0;
+}
+
+/**
+ * Get full encoding string.
+ * @private
+ */
+
+function getFullEncoding(spec) {
+  return spec.encoding;
+}
+
+/**
+ * Check if a spec has any quality.
+ * @private
+ */
+
+function isQuality(spec) {
+  return spec.q > 0;
+}
diff --git a/server/node_modules/negotiator/lib/language.js b/server/node_modules/negotiator/lib/language.js
new file mode 100644
index 0000000..a231672
--- /dev/null
+++ b/server/node_modules/negotiator/lib/language.js
@@ -0,0 +1,179 @@
+/**
+ * negotiator
+ * Copyright(c) 2012 Isaac Z. Schlueter
+ * Copyright(c) 2014 Federico Romero
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = preferredLanguages;
+module.exports.preferredLanguages = preferredLanguages;
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var simpleLanguageRegExp = /^\s*([^\s\-;]+)(?:-([^\s;]+))?\s*(?:;(.*))?$/;
+
+/**
+ * Parse the Accept-Language header.
+ * @private
+ */
+
+function parseAcceptLanguage(accept) {
+  var accepts = accept.split(',');
+
+  for (var i = 0, j = 0; i < accepts.length; i++) {
+    var language = parseLanguage(accepts[i].trim(), i);
+
+    if (language) {
+      accepts[j++] = language;
+    }
+  }
+
+  // trim accepts
+  accepts.length = j;
+
+  return accepts;
+}
+
+/**
+ * Parse a language from the Accept-Language header.
+ * @private
+ */
+
+function parseLanguage(str, i) {
+  var match = simpleLanguageRegExp.exec(str);
+  if (!match) return null;
+
+  var prefix = match[1]
+  var suffix = match[2]
+  var full = prefix
+
+  if (suffix) full += "-" + suffix;
+
+  var q = 1;
+  if (match[3]) {
+    var params = match[3].split(';')
+    for (var j = 0; j < params.length; j++) {
+      var p = params[j].split('=');
+      if (p[0] === 'q') q = parseFloat(p[1]);
+    }
+  }
+
+  return {
+    prefix: prefix,
+    suffix: suffix,
+    q: q,
+    i: i,
+    full: full
+  };
+}
+
+/**
+ * Get the priority of a language.
+ * @private
+ */
+
+function getLanguagePriority(language, accepted, index) {
+  var priority = {o: -1, q: 0, s: 0};
+
+  for (var i = 0; i < accepted.length; i++) {
+    var spec = specify(language, accepted[i], index);
+
+    if (spec && (priority.s - spec.s || priority.q - spec.q || priority.o - spec.o) < 0) {
+      priority = spec;
+    }
+  }
+
+  return priority;
+}
+
+/**
+ * Get the specificity of the language.
+ * @private
+ */
+
+function specify(language, spec, index) {
+  var p = parseLanguage(language)
+  if (!p) return null;
+  var s = 0;
+  if(spec.full.toLowerCase() === p.full.toLowerCase()){
+    s |= 4;
+  } else if (spec.prefix.toLowerCase() === p.full.toLowerCase()) {
+    s |= 2;
+  } else if (spec.full.toLowerCase() === p.prefix.toLowerCase()) {
+    s |= 1;
+  } else if (spec.full !== '*' ) {
+    return null
+  }
+
+  return {
+    i: index,
+    o: spec.i,
+    q: spec.q,
+    s: s
+  }
+};
+
+/**
+ * Get the preferred languages from an Accept-Language header.
+ * @public
+ */
+
+function preferredLanguages(accept, provided) {
+  // RFC 2616 sec 14.4: no header = *
+  var accepts = parseAcceptLanguage(accept === undefined ? '*' : accept || '');
+
+  if (!provided) {
+    // sorted list of all languages
+    return accepts
+      .filter(isQuality)
+      .sort(compareSpecs)
+      .map(getFullLanguage);
+  }
+
+  var priorities = provided.map(function getPriority(type, index) {
+    return getLanguagePriority(type, accepts, index);
+  });
+
+  // sorted list of accepted languages
+  return priorities.filter(isQuality).sort(compareSpecs).map(function getLanguage(priority) {
+    return provided[priorities.indexOf(priority)];
+  });
+}
+
+/**
+ * Compare two specs.
+ * @private
+ */
+
+function compareSpecs(a, b) {
+  return (b.q - a.q) || (b.s - a.s) || (a.o - b.o) || (a.i - b.i) || 0;
+}
+
+/**
+ * Get full language string.
+ * @private
+ */
+
+function getFullLanguage(spec) {
+  return spec.full;
+}
+
+/**
+ * Check if a spec has any quality.
+ * @private
+ */
+
+function isQuality(spec) {
+  return spec.q > 0;
+}
diff --git a/server/node_modules/negotiator/lib/mediaType.js b/server/node_modules/negotiator/lib/mediaType.js
new file mode 100644
index 0000000..67309dd
--- /dev/null
+++ b/server/node_modules/negotiator/lib/mediaType.js
@@ -0,0 +1,294 @@
+/**
+ * negotiator
+ * Copyright(c) 2012 Isaac Z. Schlueter
+ * Copyright(c) 2014 Federico Romero
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict';
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = preferredMediaTypes;
+module.exports.preferredMediaTypes = preferredMediaTypes;
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var simpleMediaTypeRegExp = /^\s*([^\s\/;]+)\/([^;\s]+)\s*(?:;(.*))?$/;
+
+/**
+ * Parse the Accept header.
+ * @private
+ */
+
+function parseAccept(accept) {
+  var accepts = splitMediaTypes(accept);
+
+  for (var i = 0, j = 0; i < accepts.length; i++) {
+    var mediaType = parseMediaType(accepts[i].trim(), i);
+
+    if (mediaType) {
+      accepts[j++] = mediaType;
+    }
+  }
+
+  // trim accepts
+  accepts.length = j;
+
+  return accepts;
+}
+
+/**
+ * Parse a media type from the Accept header.
+ * @private
+ */
+
+function parseMediaType(str, i) {
+  var match = simpleMediaTypeRegExp.exec(str);
+  if (!match) return null;
+
+  var params = Object.create(null);
+  var q = 1;
+  var subtype = match[2];
+  var type = match[1];
+
+  if (match[3]) {
+    var kvps = splitParameters(match[3]).map(splitKeyValuePair);
+
+    for (var j = 0; j < kvps.length; j++) {
+      var pair = kvps[j];
+      var key = pair[0].toLowerCase();
+      var val = pair[1];
+
+      // get the value, unwrapping quotes
+      var value = val && val[0] === '"' && val[val.length - 1] === '"'
+        ? val.substr(1, val.length - 2)
+        : val;
+
+      if (key === 'q') {
+        q = parseFloat(value);
+        break;
+      }
+
+      // store parameter
+      params[key] = value;
+    }
+  }
+
+  return {
+    type: type,
+    subtype: subtype,
+    params: params,
+    q: q,
+    i: i
+  };
+}
+
+/**
+ * Get the priority of a media type.
+ * @private
+ */
+
+function getMediaTypePriority(type, accepted, index) {
+  var priority = {o: -1, q: 0, s: 0};
+
+  for (var i = 0; i < accepted.length; i++) {
+    var spec = specify(type, accepted[i], index);
+
+    if (spec && (priority.s - spec.s || priority.q - spec.q || priority.o - spec.o) < 0) {
+      priority = spec;
+    }
+  }
+
+  return priority;
+}
+
+/**
+ * Get the specificity of the media type.
+ * @private
+ */
+
+function specify(type, spec, index) {
+  var p = parseMediaType(type);
+  var s = 0;
+
+  if (!p) {
+    return null;
+  }
+
+  if(spec.type.toLowerCase() == p.type.toLowerCase()) {
+    s |= 4
+  } else if(spec.type != '*') {
+    return null;
+  }
+
+  if(spec.subtype.toLowerCase() == p.subtype.toLowerCase()) {
+    s |= 2
+  } else if(spec.subtype != '*') {
+    return null;
+  }
+
+  var keys = Object.keys(spec.params);
+  if (keys.length > 0) {
+    if (keys.every(function (k) {
+      return spec.params[k] == '*' || (spec.params[k] || '').toLowerCase() == (p.params[k] || '').toLowerCase();
+    })) {
+      s |= 1
+    } else {
+      return null
+    }
+  }
+
+  return {
+    i: index,
+    o: spec.i,
+    q: spec.q,
+    s: s,
+  }
+}
+
+/**
+ * Get the preferred media types from an Accept header.
+ * @public
+ */
+
+function preferredMediaTypes(accept, provided) {
+  // RFC 2616 sec 14.2: no header = */*
+  var accepts = parseAccept(accept === undefined ? '*/*' : accept || '');
+
+  if (!provided) {
+    // sorted list of all types
+    return accepts
+      .filter(isQuality)
+      .sort(compareSpecs)
+      .map(getFullType);
+  }
+
+  var priorities = provided.map(function getPriority(type, index) {
+    return getMediaTypePriority(type, accepts, index);
+  });
+
+  // sorted list of accepted types
+  return priorities.filter(isQuality).sort(compareSpecs).map(function getType(priority) {
+    return provided[priorities.indexOf(priority)];
+  });
+}
+
+/**
+ * Compare two specs.
+ * @private
+ */
+
+function compareSpecs(a, b) {
+  return (b.q - a.q) || (b.s - a.s) || (a.o - b.o) || (a.i - b.i) || 0;
+}
+
+/**
+ * Get full type string.
+ * @private
+ */
+
+function getFullType(spec) {
+  return spec.type + '/' + spec.subtype;
+}
+
+/**
+ * Check if a spec has any quality.
+ * @private
+ */
+
+function isQuality(spec) {
+  return spec.q > 0;
+}
+
+/**
+ * Count the number of quotes in a string.
+ * @private
+ */
+
+function quoteCount(string) {
+  var count = 0;
+  var index = 0;
+
+  while ((index = string.indexOf('"', index)) !== -1) {
+    count++;
+    index++;
+  }
+
+  return count;
+}
+
+/**
+ * Split a key value pair.
+ * @private
+ */
+
+function splitKeyValuePair(str) {
+  var index = str.indexOf('=');
+  var key;
+  var val;
+
+  if (index === -1) {
+    key = str;
+  } else {
+    key = str.substr(0, index);
+    val = str.substr(index + 1);
+  }
+
+  return [key, val];
+}
+
+/**
+ * Split an Accept header into media types.
+ * @private
+ */
+
+function splitMediaTypes(accept) {
+  var accepts = accept.split(',');
+
+  for (var i = 1, j = 0; i < accepts.length; i++) {
+    if (quoteCount(accepts[j]) % 2 == 0) {
+      accepts[++j] = accepts[i];
+    } else {
+      accepts[j] += ',' + accepts[i];
+    }
+  }
+
+  // trim accepts
+  accepts.length = j + 1;
+
+  return accepts;
+}
+
+/**
+ * Split a string of parameters.
+ * @private
+ */
+
+function splitParameters(str) {
+  var parameters = str.split(';');
+
+  for (var i = 1, j = 0; i < parameters.length; i++) {
+    if (quoteCount(parameters[j]) % 2 == 0) {
+      parameters[++j] = parameters[i];
+    } else {
+      parameters[j] += ';' + parameters[i];
+    }
+  }
+
+  // trim parameters
+  parameters.length = j + 1;
+
+  for (var i = 0; i < parameters.length; i++) {
+    parameters[i] = parameters[i].trim();
+  }
+
+  return parameters;
+}
diff --git a/server/node_modules/negotiator/package.json b/server/node_modules/negotiator/package.json
new file mode 100644
index 0000000..297635f
--- /dev/null
+++ b/server/node_modules/negotiator/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "negotiator",
+  "description": "HTTP content negotiation",
+  "version": "0.6.3",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Federico Romero <federico.romero@outboxlabs.com>",
+    "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "http",
+    "content negotiation",
+    "accept",
+    "accept-language",
+    "accept-encoding",
+    "accept-charset"
+  ],
+  "repository": "jshttp/negotiator",
+  "devDependencies": {
+    "eslint": "7.32.0",
+    "eslint-plugin-markdown": "2.2.1",
+    "mocha": "9.1.3",
+    "nyc": "15.1.0"
+  },
+  "files": [
+    "lib/",
+    "HISTORY.md",
+    "LICENSE",
+    "index.js",
+    "README.md"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --check-leaks --bail test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/node-abi/LICENSE b/server/node_modules/node-abi/LICENSE
new file mode 100644
index 0000000..5513de0
--- /dev/null
+++ b/server/node_modules/node-abi/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2016 Lukas Geiger
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/node-abi/README.md b/server/node_modules/node-abi/README.md
new file mode 100644
index 0000000..680a0d0
--- /dev/null
+++ b/server/node_modules/node-abi/README.md
@@ -0,0 +1,54 @@
+# Node.js ABI
+
+[![Build Status](https://github.com/electron/node-abi/actions/workflows/test.yml/badge.svg)](https://github.com/electron/node-abi/actions/workflows/test.yml)
+[![Auto-update ABI JSON file](https://github.com/electron/node-abi/actions/workflows/update-abi.yml/badge.svg)](https://github.com/electron/node-abi/actions/workflows/update-abi.yml)
+[![Snyk badge](https://snyk.io/test/github/electron/node-abi/badge.svg)](https://snyk.io/test/github/electron/node-abi)
+[![npm version](http://img.shields.io/npm/v/node-abi.svg)](https://npmjs.org/package/node-abi)
+
+Get the Node ABI (application binary interface) for a given target and runtime, and vice versa.
+
+## Installation
+
+```shell
+npm install node-abi
+```
+
+## Usage
+
+```javascript
+const nodeAbi = require('node-abi')
+
+nodeAbi.getAbi('7.2.0', 'node')
+// '51'
+nodeAbi.getAbi('1.4.10', 'electron')
+// '50'
+nodeAbi.getTarget('51', 'node')
+// '7.2.0'
+nodeAbi.getTarget('50', 'electron')
+// '1.4.15'
+
+nodeAbi.allTargets
+// [
+//  { runtime: 'node', target: '0.10.48', abi: '11', lts: false },
+//  { runtime: 'node', target: '0.12.17', abi: '14', lts: false },
+//  { runtime: 'node', target: '4.6.1', abi: '46', lts: true },
+//  { runtime: 'node', target: '5.12.0', abi: '47', lts: false },
+//  { runtime: 'node', target: '6.9.4', abi: '48', lts: true },
+//  { runtime: 'node', target: '7.4.0', abi: '51', lts: false },
+//  { runtime: 'electron', target: '1.0.2', abi: '47', lts: false },
+//  { runtime: 'electron', target: '1.2.8', abi: '48', lts: false },
+//  { runtime: 'electron', target: '1.3.13', abi: '49', lts: false },
+//  { runtime: 'electron', target: '1.4.15', abi: '50', lts: false }
+// ]
+nodeAbi.deprecatedTargets
+nodeAbi.supportedTargets
+nodeAbi.additionalTargets
+nodeAbi.futureTargets
+// ...
+```
+
+## References
+
+- https://github.com/lgeiger/electron-abi
+- https://nodejs.org/en/download/releases/
+- https://github.com/nodejs/Release
diff --git a/server/node_modules/node-abi/abi_registry.json b/server/node_modules/node-abi/abi_registry.json
new file mode 100644
index 0000000..0544255
--- /dev/null
+++ b/server/node_modules/node-abi/abi_registry.json
@@ -0,0 +1,432 @@
+[
+  {
+    "runtime": "node",
+    "target": "11.0.0",
+    "lts": false,
+    "future": false,
+    "abi": "67"
+  },
+  {
+    "runtime": "node",
+    "target": "12.0.0",
+    "lts": [
+      "2019-10-21",
+      "2020-11-30"
+    ],
+    "future": false,
+    "abi": "72"
+  },
+  {
+    "runtime": "node",
+    "target": "13.0.0",
+    "lts": false,
+    "future": false,
+    "abi": "79"
+  },
+  {
+    "runtime": "node",
+    "target": "14.0.0",
+    "lts": [
+      "2020-10-27",
+      "2021-10-19"
+    ],
+    "future": false,
+    "abi": "83"
+  },
+  {
+    "runtime": "node",
+    "target": "15.0.0",
+    "lts": false,
+    "future": false,
+    "abi": "88"
+  },
+  {
+    "runtime": "node",
+    "target": "16.0.0",
+    "lts": [
+      "2021-10-26",
+      "2022-10-18"
+    ],
+    "future": false,
+    "abi": "93"
+  },
+  {
+    "runtime": "node",
+    "target": "17.0.0",
+    "lts": false,
+    "future": false,
+    "abi": "102"
+  },
+  {
+    "runtime": "node",
+    "target": "18.0.0",
+    "lts": [
+      "2022-10-25",
+      "2023-10-18"
+    ],
+    "future": false,
+    "abi": "108"
+  },
+  {
+    "runtime": "node",
+    "target": "19.0.0",
+    "lts": false,
+    "future": false,
+    "abi": "111"
+  },
+  {
+    "runtime": "node",
+    "target": "20.0.0",
+    "lts": [
+      "2023-10-24",
+      "2024-10-22"
+    ],
+    "future": false,
+    "abi": "115"
+  },
+  {
+    "runtime": "node",
+    "target": "21.0.0",
+    "lts": false,
+    "future": false,
+    "abi": "120"
+  },
+  {
+    "runtime": "node",
+    "target": "22.0.0",
+    "lts": [
+      "2024-10-29",
+      "2025-10-21"
+    ],
+    "future": false,
+    "abi": "127"
+  },
+  {
+    "runtime": "node",
+    "target": "23.0.0",
+    "lts": false,
+    "future": false,
+    "abi": "131"
+  },
+  {
+    "runtime": "node",
+    "target": "24.0.0",
+    "lts": [
+      "2025-10-28",
+      "2026-10-20"
+    ],
+    "future": false,
+    "abi": "137"
+  },
+  {
+    "runtime": "node",
+    "target": "25.0.0",
+    "lts": false,
+    "future": false,
+    "abi": "141"
+  },
+  {
+    "runtime": "node",
+    "target": "26.0.0",
+    "lts": [
+      "2026-10-28",
+      "2027-10-20"
+    ],
+    "future": true,
+    "abi": "144"
+  },
+  {
+    "abi": "70",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "5.0.0-beta.9"
+  },
+  {
+    "abi": "73",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "6.0.0-beta.1"
+  },
+  {
+    "abi": "75",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "7.0.0-beta.1"
+  },
+  {
+    "abi": "76",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "9.0.0-beta.1"
+  },
+  {
+    "abi": "76",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "8.0.0-beta.1"
+  },
+  {
+    "abi": "80",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "9.0.0-beta.2"
+  },
+  {
+    "abi": "82",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "11.0.0-beta.1"
+  },
+  {
+    "abi": "82",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "10.0.0-beta.1"
+  },
+  {
+    "abi": "85",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "11.0.0-beta.11"
+  },
+  {
+    "abi": "87",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "12.0.0-beta.1"
+  },
+  {
+    "abi": "89",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "15.0.0-alpha.1"
+  },
+  {
+    "abi": "89",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "14.0.0-beta.1"
+  },
+  {
+    "abi": "89",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "13.0.0-beta.2"
+  },
+  {
+    "abi": "97",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "14.0.2"
+  },
+  {
+    "abi": "98",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "15.0.0-beta.7"
+  },
+  {
+    "abi": "99",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "16.0.0-alpha.1"
+  },
+  {
+    "abi": "101",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "17.0.0-alpha.1"
+  },
+  {
+    "abi": "103",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "18.0.0-alpha.1"
+  },
+  {
+    "abi": "106",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "19.0.0-alpha.1"
+  },
+  {
+    "abi": "107",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "20.0.0-alpha.1"
+  },
+  {
+    "abi": "109",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "21.0.0-alpha.1"
+  },
+  {
+    "abi": "110",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "22.0.0-alpha.1"
+  },
+  {
+    "abi": "113",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "23.0.0-alpha.1"
+  },
+  {
+    "abi": "114",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "24.0.0-alpha.1"
+  },
+  {
+    "abi": "116",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "26.0.0-alpha.1"
+  },
+  {
+    "abi": "116",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "25.0.0-alpha.1"
+  },
+  {
+    "abi": "118",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "27.0.0-alpha.1"
+  },
+  {
+    "abi": "119",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "28.0.0-alpha.1"
+  },
+  {
+    "abi": "121",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "29.0.0-alpha.1"
+  },
+  {
+    "abi": "123",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "31.0.0-alpha.1"
+  },
+  {
+    "abi": "123",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "30.0.0-alpha.1"
+  },
+  {
+    "abi": "125",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "31.0.0-beta.7"
+  },
+  {
+    "abi": "128",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "32.0.0-alpha.1"
+  },
+  {
+    "abi": "130",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "33.0.0-alpha.1"
+  },
+  {
+    "abi": "132",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "34.0.0-alpha.1"
+  },
+  {
+    "abi": "133",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "35.0.0-alpha.1"
+  },
+  {
+    "abi": "135",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "36.0.0-alpha.1"
+  },
+  {
+    "abi": "136",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "37.0.0-alpha.1"
+  },
+  {
+    "abi": "139",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "38.0.0-alpha.1"
+  },
+  {
+    "abi": "140",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "39.0.0-alpha.1"
+  },
+  {
+    "abi": "143",
+    "future": false,
+    "lts": false,
+    "runtime": "electron",
+    "target": "40.0.0-alpha.2"
+  },
+  {
+    "abi": "145",
+    "future": true,
+    "lts": false,
+    "runtime": "electron",
+    "target": "41.0.0-alpha.1"
+  }
+]
\ No newline at end of file
diff --git a/server/node_modules/node-abi/index.js b/server/node_modules/node-abi/index.js
new file mode 100644
index 0000000..f656135
--- /dev/null
+++ b/server/node_modules/node-abi/index.js
@@ -0,0 +1,179 @@
+var semver = require('semver')
+
+function getNextTarget (runtime, targets) {
+  if (targets == null) targets = allTargets
+  var latest = targets.filter(function (t) { return t.runtime === runtime }).slice(-1)[0]
+  var increment = runtime === 'electron' ? 'minor' : 'major'
+  var next = semver.inc(latest.target, increment)
+  // Electron releases appear in the registry in their beta form, sometimes there is
+  // no active beta line.  During this time we need to double bump
+  if (runtime === 'electron' && semver.parse(latest.target).prerelease.length) {
+    next = semver.inc(next, 'major')
+  }
+  return next
+}
+
+function getAbi (target, runtime) {
+  if (target === String(Number(target))) return target
+  if (target) target = target.replace(/^v/, '')
+  if (!runtime) runtime = 'node'
+
+  if (runtime === 'node') {
+    if (!target) return process.versions.modules
+    if (target === process.versions.node) return process.versions.modules
+  }
+
+  var abi
+  var lastTarget
+
+  for (var i = 0; i < allTargets.length; i++) {
+    var t = allTargets[i]
+    if (t.runtime !== runtime) continue
+    if (semver.lte(t.target, target) && (!lastTarget || semver.gte(t.target, lastTarget))) {
+      abi = t.abi
+      lastTarget = t.target
+    }
+  }
+
+  if (abi && semver.lt(target, getNextTarget(runtime))) return abi
+  throw new Error('Could not detect abi for version ' + target + ' and runtime ' + runtime + '.  Updating "node-abi" might help solve this issue if it is a new release of ' + runtime)
+}
+
+function getTarget (abi, runtime) {
+  if (abi && abi !== String(Number(abi))) return abi
+  if (!runtime) runtime = 'node'
+
+  if (runtime === 'node' && !abi) return process.versions.node
+
+  var match = allTargets
+    .filter(function (t) {
+      return t.abi === abi && t.runtime === runtime
+    })
+    .map(function (t) {
+      return t.target
+    })
+  if (match.length) {
+    var betaSeparatorIndex = match[0].indexOf("-")
+    return betaSeparatorIndex > -1
+      ? match[0].substring(0, betaSeparatorIndex)
+      : match[0]
+  }
+
+  throw new Error('Could not detect target for abi ' + abi + ' and runtime ' + runtime)
+}
+
+function sortByTargetFn (a, b) {
+  var abiComp = Number(a.abi) - Number(b.abi)
+  if (abiComp !== 0) return abiComp
+  if (a.target < b.target) return -1
+  if (a.target > b.target) return 1
+  return 0
+}
+
+function loadGeneratedTargets () {
+  var registry = require('./abi_registry.json')
+  var targets = {
+    supported: [],
+    additional: [],
+    future: []
+  }
+
+  registry.forEach(function (item) {
+    var target = {
+      runtime: item.runtime,
+      target: item.target,
+      abi: item.abi
+    }
+    if (item.lts) {
+      var startDate = new Date(Date.parse(item.lts[0]))
+      var endDate = new Date(Date.parse(item.lts[1]))
+      var currentDate = new Date()
+      target.lts = startDate < currentDate && currentDate < endDate
+    } else {
+      target.lts = false
+    }
+
+    if (target.runtime === 'node-webkit') {
+      targets.additional.push(target)
+    } else if (item.future) {
+      targets.future.push(target)
+    } else {
+      targets.supported.push(target)
+    }
+  })
+
+  targets.supported.sort(sortByTargetFn)
+  targets.additional.sort(sortByTargetFn)
+  targets.future.sort(sortByTargetFn)
+
+  return targets
+}
+
+var generatedTargets = loadGeneratedTargets()
+
+var supportedTargets = [
+  {runtime: 'node', target: '5.0.0', abi: '47', lts: false},
+  {runtime: 'node', target: '6.0.0', abi: '48', lts: false},
+  {runtime: 'node', target: '7.0.0', abi: '51', lts: false},
+  {runtime: 'node', target: '8.0.0', abi: '57', lts: false},
+  {runtime: 'node', target: '9.0.0', abi: '59', lts: false},
+  {runtime: 'node', target: '10.0.0', abi: '64', lts: new Date(2018, 10, 1) < new Date() && new Date() < new Date(2020, 4, 31)},
+  {runtime: 'electron', target: '0.36.0', abi: '47', lts: false},
+  {runtime: 'electron', target: '1.1.0', abi: '48', lts: false},
+  {runtime: 'electron', target: '1.3.0', abi: '49', lts: false},
+  {runtime: 'electron', target: '1.4.0', abi: '50', lts: false},
+  {runtime: 'electron', target: '1.5.0', abi: '51', lts: false},
+  {runtime: 'electron', target: '1.6.0', abi: '53', lts: false},
+  {runtime: 'electron', target: '1.7.0', abi: '54', lts: false},
+  {runtime: 'electron', target: '1.8.0', abi: '57', lts: false},
+  {runtime: 'electron', target: '2.0.0', abi: '57', lts: false},
+  {runtime: 'electron', target: '3.0.0', abi: '64', lts: false},
+  {runtime: 'electron', target: '4.0.0', abi: '64', lts: false},
+  {runtime: 'electron', target: '4.0.4', abi: '69', lts: false}
+]
+
+supportedTargets.push.apply(supportedTargets, generatedTargets.supported)
+
+var additionalTargets = [
+  {runtime: 'node-webkit', target: '0.13.0', abi: '47', lts: false},
+  {runtime: 'node-webkit', target: '0.15.0', abi: '48', lts: false},
+  {runtime: 'node-webkit', target: '0.18.3', abi: '51', lts: false},
+  {runtime: 'node-webkit', target: '0.23.0', abi: '57', lts: false},
+  {runtime: 'node-webkit', target: '0.26.5', abi: '59', lts: false}
+]
+
+additionalTargets.push.apply(additionalTargets, generatedTargets.additional)
+
+var deprecatedTargets = [
+  {runtime: 'node', target: '0.2.0', abi: '1', lts: false},
+  {runtime: 'node', target: '0.9.1', abi: '0x000A', lts: false},
+  {runtime: 'node', target: '0.9.9', abi: '0x000B', lts: false},
+  {runtime: 'node', target: '0.10.4', abi: '11', lts: false},
+  {runtime: 'node', target: '0.11.0', abi: '0x000C', lts: false},
+  {runtime: 'node', target: '0.11.8', abi: '13', lts: false},
+  {runtime: 'node', target: '0.11.11', abi: '14', lts: false},
+  {runtime: 'node', target: '1.0.0', abi: '42', lts: false},
+  {runtime: 'node', target: '1.1.0', abi: '43', lts: false},
+  {runtime: 'node', target: '2.0.0', abi: '44', lts: false},
+  {runtime: 'node', target: '3.0.0', abi: '45', lts: false},
+  {runtime: 'node', target: '4.0.0', abi: '46', lts: false},
+  {runtime: 'electron', target: '0.30.0', abi: '44', lts: false},
+  {runtime: 'electron', target: '0.31.0', abi: '45', lts: false},
+  {runtime: 'electron', target: '0.33.0', abi: '46', lts: false}
+]
+
+var futureTargets = generatedTargets.future
+
+var allTargets = deprecatedTargets
+  .concat(supportedTargets)
+  .concat(additionalTargets)
+  .concat(futureTargets)
+
+exports.getAbi = getAbi
+exports.getTarget = getTarget
+exports.deprecatedTargets = deprecatedTargets
+exports.supportedTargets = supportedTargets
+exports.additionalTargets = additionalTargets
+exports.futureTargets = futureTargets
+exports.allTargets = allTargets
+exports._getNextTarget = getNextTarget
diff --git a/server/node_modules/node-abi/package.json b/server/node_modules/node-abi/package.json
new file mode 100644
index 0000000..7e2c53e
--- /dev/null
+++ b/server/node_modules/node-abi/package.json
@@ -0,0 +1,45 @@
+{
+  "name": "node-abi",
+  "version": "3.87.0",
+  "description": "Get the Node ABI for a given target and runtime, and vice versa.",
+  "main": "index.js",
+  "scripts": {
+    "test": "tape test/index.js",
+    "update-abi-registry": "node --unhandled-rejections=strict scripts/update-abi-registry.js"
+  },
+  "files": [
+    "abi_registry.json"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/electron/node-abi.git"
+  },
+  "keywords": [
+    "node",
+    "electron",
+    "node_module_version",
+    "abi",
+    "v8"
+  ],
+  "author": "Lukas Geiger",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/electron/node-abi/issues"
+  },
+  "homepage": "https://github.com/electron/node-abi#readme",
+  "devDependencies": {
+    "@semantic-release/npm": "13.0.0-alpha.15",
+    "semantic-release": "^24.2.7",
+    "tape": "^5.3.1"
+  },
+  "dependencies": {
+    "semver": "^7.3.5"
+  },
+  "engines": {
+    "node": ">=10"
+  },
+  "publishConfig": {
+    "provenance": true
+  },
+  "packageManager": "yarn@4.10.3+sha512.c38cafb5c7bb273f3926d04e55e1d8c9dfa7d9c3ea1f36a4868fa028b9e5f72298f0b7f401ad5eb921749eb012eb1c3bb74bf7503df3ee43fd600d14a018266f"
+}
diff --git a/server/node_modules/node-addon-api/LICENSE.md b/server/node_modules/node-addon-api/LICENSE.md
new file mode 100644
index 0000000..819d91a
--- /dev/null
+++ b/server/node_modules/node-addon-api/LICENSE.md
@@ -0,0 +1,9 @@
+The MIT License (MIT)
+
+Copyright (c) 2017 [Node.js API collaborators](https://github.com/nodejs/node-addon-api#collaborators)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/node-addon-api/README.md b/server/node_modules/node-addon-api/README.md
new file mode 100644
index 0000000..89a36ef
--- /dev/null
+++ b/server/node_modules/node-addon-api/README.md
@@ -0,0 +1,95 @@
+# **node-addon-api module**
+
+[![codecov](https://codecov.io/gh/nodejs/node-addon-api/branch/main/graph/badge.svg)](https://app.codecov.io/gh/nodejs/node-addon-api/tree/main)
+
+[![NPM](https://nodei.co/npm/node-addon-api.png?downloads=true&downloadRank=true)](https://nodei.co/npm/node-addon-api/) [![NPM](https://nodei.co/npm-dl/node-addon-api.png?months=6&height=1)](https://nodei.co/npm/node-addon-api/)
+
+This module contains  **header-only C++ wrapper classes** which simplify
+the use of the C based [Node-API](https://nodejs.org/dist/latest/docs/api/n-api.html)
+provided by Node.js when using C++. It provides a C++ object model
+and exception handling semantics with low overhead.
+
+- [API References](doc/README.md)
+- [Badges](#badges)
+- [Contributing](#contributing)
+- [License](#license)
+
+## API References
+
+API references are available in the [doc](doc/README.md) directory.
+
+
+## Current version: 8.5.0
+
+
+(See [CHANGELOG.md](CHANGELOG.md) for complete Changelog)
+
+node-addon-api is based on [Node-API](https://nodejs.org/api/n-api.html) and supports using different Node-API versions.
+This allows addons built with it to run with Node.js versions which support the targeted Node-API version.
+**However** the node-addon-api support model is to support only the active LTS Node.js versions. This means that
+every year there will be a new major which drops support for the Node.js LTS version which has gone out of service.
+
+The oldest Node.js version supported by the current version of node-addon-api is Node.js 18.x.
+
+## Badges
+
+The use of badges is recommended to indicate the minimum version of Node-API
+required for the module. This helps to determine which Node.js major versions are
+supported. Addon maintainers can consult the [Node-API support matrix][] to determine
+which Node.js versions provide a given Node-API version. The following badges are
+available:
+
+![Node-API v1 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v1%20Badge.svg)
+![Node-API v2 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v2%20Badge.svg)
+![Node-API v3 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v3%20Badge.svg)
+![Node-API v4 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v4%20Badge.svg)
+![Node-API v5 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v5%20Badge.svg)
+![Node-API v6 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v6%20Badge.svg)
+![Node-API v7 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v7%20Badge.svg)
+![Node-API v8 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v8%20Badge.svg)
+![Node-API v9 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v9%20Badge.svg)
+![Node-API Experimental Version Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20Experimental%20Version%20Badge.svg)
+
+## Contributing
+
+We love contributions from the community to **node-addon-api**!
+See [CONTRIBUTING.md](CONTRIBUTING.md) for more details on our philosophy around extending this module.
+
+## Team members
+
+### Active
+
+| Name                | GitHub Link                                           |
+| ------------------- | ----------------------------------------------------- |
+| Anna Henningsen     | [addaleax](https://github.com/addaleax)               |
+| Chengzhong Wu       | [legendecas](https://github.com/legendecas)           |
+| Jack Xia            | [JckXia](https://github.com/JckXia)                   |
+| Kevin Eady          | [KevinEady](https://github.com/KevinEady)             |
+| Michael Dawson      | [mhdawson](https://github.com/mhdawson)               |
+| Nicola Del Gobbo    | [NickNaso](https://github.com/NickNaso)               |
+| Vladimir Morozov    | [vmoroz](https://github.com/vmoroz)                   |
+
+<details>
+
+<summary>Emeritus</summary>
+
+### Emeritus
+
+| Name                | GitHub Link                                           |
+| ------------------- | ----------------------------------------------------- |
+| Arunesh Chandra     | [aruneshchandra](https://github.com/aruneshchandra)   |
+| Benjamin Byholm     | [kkoopa](https://github.com/kkoopa)                   |
+| Gabriel Schulhof    | [gabrielschulhof](https://github.com/gabrielschulhof) |
+| Hitesh Kanwathirtha | [digitalinfinity](https://github.com/digitalinfinity) |
+| Jason Ginchereau    | [jasongin](https://github.com/jasongin)               |
+| Jim Schlight        | [jschlight](https://github.com/jschlight)             |
+| Sampson Gao         | [sampsongao](https://github.com/sampsongao)           |
+| Taylor Woll         | [boingoing](https://github.com/boingoing)             |
+
+</details>
+
+## License
+
+Licensed under [MIT](./LICENSE.md)
+
+[Node-API support matrix]: https://nodejs.org/dist/latest/docs/api/n-api.html#node-api-version-matrix
diff --git a/server/node_modules/node-addon-api/common.gypi b/server/node_modules/node-addon-api/common.gypi
new file mode 100644
index 0000000..e594f14
--- /dev/null
+++ b/server/node_modules/node-addon-api/common.gypi
@@ -0,0 +1,21 @@
+{
+  'variables': {
+    'NAPI_VERSION%': "<!(node -p \"process.env.NAPI_VERSION || process.versions.napi\")",
+    'disable_deprecated': "<!(node -p \"process.env['npm_config_disable_deprecated']\")"
+  },
+  'conditions': [
+    ['NAPI_VERSION!=""', { 'defines': ['NAPI_VERSION=<@(NAPI_VERSION)'] } ],
+    ['NAPI_VERSION==2147483647', { 'defines': ['NAPI_EXPERIMENTAL'] } ],
+    ['disable_deprecated=="true"', {
+      'defines': ['NODE_ADDON_API_DISABLE_DEPRECATED']
+    }],
+    ['OS=="mac"', {
+      'cflags+': ['-fvisibility=hidden'],
+      'xcode_settings': {
+        'OTHER_CFLAGS': ['-fvisibility=hidden']
+      }
+    }]
+  ],
+  'cflags': [ '-Werror', '-Wall', '-Wextra', '-Wpedantic', '-Wunused-parameter' ],
+  'cflags_cc': [ '-Werror', '-Wall', '-Wextra', '-Wpedantic', '-Wunused-parameter' ]
+}
diff --git a/server/node_modules/node-addon-api/except.gypi b/server/node_modules/node-addon-api/except.gypi
new file mode 100644
index 0000000..e2fb2c5
--- /dev/null
+++ b/server/node_modules/node-addon-api/except.gypi
@@ -0,0 +1,25 @@
+{
+  'defines': [ 'NAPI_CPP_EXCEPTIONS' ],
+  'cflags!': [ '-fno-exceptions' ],
+  'cflags_cc!': [ '-fno-exceptions' ],
+  'conditions': [
+    ["OS=='win'", {
+      "defines": [
+        "_HAS_EXCEPTIONS=1"
+      ],
+      "msvs_settings": {
+        "VCCLCompilerTool": {
+          "ExceptionHandling": 1,
+          'EnablePREfast': 'true',
+        },
+      },
+    }],
+    ["OS=='mac'", {
+      'xcode_settings': {
+        'GCC_ENABLE_CPP_EXCEPTIONS': 'YES',
+        'CLANG_CXX_LIBRARY': 'libc++',
+        'MACOSX_DEPLOYMENT_TARGET': '10.7',
+      },
+    }],
+  ],
+}
diff --git a/server/node_modules/node-addon-api/index.js b/server/node_modules/node-addon-api/index.js
new file mode 100644
index 0000000..e235cc3
--- /dev/null
+++ b/server/node_modules/node-addon-api/index.js
@@ -0,0 +1,14 @@
+const path = require('path');
+const { version } = require('./package.json');
+
+const includeDir = path.relative('.', __dirname);
+
+module.exports = {
+  include: `"${__dirname}"`, // deprecated, can be removed as part of 4.0.0
+  include_dir: includeDir,
+  gyp: path.join(includeDir, 'node_api.gyp:nothing'), // deprecated.
+  targets: path.join(includeDir, 'node_addon_api.gyp'),
+  version,
+  isNodeApiBuiltin: true,
+  needsFlag: false
+};
diff --git a/server/node_modules/node-addon-api/napi-inl.deprecated.h b/server/node_modules/node-addon-api/napi-inl.deprecated.h
new file mode 100644
index 0000000..3ddbb2e
--- /dev/null
+++ b/server/node_modules/node-addon-api/napi-inl.deprecated.h
@@ -0,0 +1,186 @@
+#ifndef SRC_NAPI_INL_DEPRECATED_H_
+#define SRC_NAPI_INL_DEPRECATED_H_
+
+////////////////////////////////////////////////////////////////////////////////
+// PropertyDescriptor class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    const char* utf8name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using CbData = details::CallbackData<Getter, Napi::Value>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({getter, nullptr});
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    const std::string& utf8name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor(utf8name.c_str(), getter, attributes, data);
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    napi_value name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using CbData = details::CallbackData<Getter, Napi::Value>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({getter, nullptr});
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Name name, Getter getter, napi_property_attributes attributes, void* data) {
+  napi_value nameValue = name;
+  return PropertyDescriptor::Accessor(nameValue, getter, attributes, data);
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    const char* utf8name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using CbData = details::AccessorCallbackData<Getter, Setter>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({getter, setter, nullptr});
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             CbData::GetterWrapper,
+                             CbData::SetterWrapper,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    const std::string& utf8name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor(utf8name.c_str(), getter, setter, attributes, data);
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    napi_value name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using CbData = details::AccessorCallbackData<Getter, Setter>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({getter, setter, nullptr});
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             CbData::GetterWrapper,
+                             CbData::SetterWrapper,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Name name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  napi_value nameValue = name;
+  return PropertyDescriptor::Accessor(
+      nameValue, getter, setter, attributes, data);
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    const char* utf8name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using ReturnType = decltype(cb(CallbackInfo(nullptr, nullptr)));
+  using CbData = details::CallbackData<Callable, ReturnType>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({cb, nullptr});
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    const std::string& utf8name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* data) {
+  return Function(utf8name.c_str(), cb, attributes, data);
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    napi_value name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using ReturnType = decltype(cb(CallbackInfo(nullptr, nullptr)));
+  using CbData = details::CallbackData<Callable, ReturnType>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({cb, nullptr});
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    Name name, Callable cb, napi_property_attributes attributes, void* data) {
+  napi_value nameValue = name;
+  return PropertyDescriptor::Function(nameValue, cb, attributes, data);
+}
+
+#endif  // !SRC_NAPI_INL_DEPRECATED_H_
diff --git a/server/node_modules/node-addon-api/napi-inl.h b/server/node_modules/node-addon-api/napi-inl.h
new file mode 100644
index 0000000..54651c1
--- /dev/null
+++ b/server/node_modules/node-addon-api/napi-inl.h
@@ -0,0 +1,7033 @@
+#ifndef SRC_NAPI_INL_H_
+#define SRC_NAPI_INL_H_
+
+////////////////////////////////////////////////////////////////////////////////
+// Node-API C++ Wrapper Classes
+//
+// Inline header-only implementations for "Node-API" ABI-stable C APIs for
+// Node.js.
+////////////////////////////////////////////////////////////////////////////////
+
+// Note: Do not include this file directly! Include "napi.h" instead.
+// This should be a no-op and is intended for better IDE integration.
+#include "napi.h"
+
+#include <algorithm>
+#include <cstdarg>
+#include <cstring>
+#if NAPI_HAS_THREADS
+#include <mutex>
+#endif  // NAPI_HAS_THREADS
+#include <type_traits>
+#include <utility>
+
+namespace Napi {
+
+#ifdef NAPI_CPP_CUSTOM_NAMESPACE
+namespace NAPI_CPP_CUSTOM_NAMESPACE {
+#endif
+
+// Helpers to handle functions exposed from C++ and internal constants.
+namespace details {
+
+// New napi_status constants not yet available in all supported versions of
+// Node.js releases. Only necessary when they are used in napi.h and napi-inl.h.
+constexpr int napi_no_external_buffers_allowed = 22;
+
+template <typename FreeType>
+inline void default_basic_finalizer(node_addon_api_basic_env /*env*/,
+                                    void* data,
+                                    void* /*hint*/) {
+  delete static_cast<FreeType*>(data);
+}
+
+// Attach a data item to an object and delete it when the object gets
+// garbage-collected.
+// TODO: Replace this code with `napi_add_finalizer()` whenever it becomes
+// available on all supported versions of Node.js.
+template <
+    typename FreeType,
+    node_addon_api_basic_finalize finalizer = default_basic_finalizer<FreeType>>
+inline napi_status AttachData(napi_env env,
+                              napi_value obj,
+                              FreeType* data,
+                              void* hint = nullptr) {
+  napi_status status;
+#if (NAPI_VERSION < 5)
+  napi_value symbol, external;
+  status = napi_create_symbol(env, nullptr, &symbol);
+  if (status == napi_ok) {
+    status = napi_create_external(env, data, finalizer, hint, &external);
+    if (status == napi_ok) {
+      napi_property_descriptor desc = {nullptr,
+                                       symbol,
+                                       nullptr,
+                                       nullptr,
+                                       nullptr,
+                                       external,
+                                       napi_default,
+                                       nullptr};
+      status = napi_define_properties(env, obj, 1, &desc);
+    }
+  }
+#else  // NAPI_VERSION >= 5
+  status = napi_add_finalizer(env, obj, data, finalizer, hint, nullptr);
+#endif
+  return status;
+}
+
+// For use in JS to C++ callback wrappers to catch any Napi::Error exceptions
+// and rethrow them as JavaScript exceptions before returning from the callback.
+template <typename Callable>
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS_ALL
+inline napi_value WrapCallback(napi_env env, Callable callback) {
+#else
+inline napi_value WrapCallback(napi_env, Callable callback) {
+#endif
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+  try {
+    return callback();
+  } catch (const Error& e) {
+    e.ThrowAsJavaScriptException();
+    return nullptr;
+  }
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS_ALL
+  catch (const std::exception& e) {
+    Napi::Error::New(env, e.what()).ThrowAsJavaScriptException();
+    return nullptr;
+  } catch (...) {
+    Napi::Error::New(env, "A native exception was thrown")
+        .ThrowAsJavaScriptException();
+    return nullptr;
+  }
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS_ALL
+#else   // NODE_ADDON_API_CPP_EXCEPTIONS
+  // When C++ exceptions are disabled, errors are immediately thrown as JS
+  // exceptions, so there is no need to catch and rethrow them here.
+  return callback();
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+}
+
+// For use in JS to C++ void callback wrappers to catch any Napi::Error
+// exceptions and rethrow them as JavaScript exceptions before returning from
+// the callback.
+template <typename Callable>
+inline void WrapVoidCallback(Callable callback) {
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+  try {
+    callback();
+  } catch (const Error& e) {
+    e.ThrowAsJavaScriptException();
+  }
+#else   // NAPI_CPP_EXCEPTIONS
+  // When C++ exceptions are disabled, errors are immediately thrown as JS
+  // exceptions, so there is no need to catch and rethrow them here.
+  callback();
+#endif  // NAPI_CPP_EXCEPTIONS
+}
+
+// For use in JS to C++ void callback wrappers to catch _any_ thrown exception
+// and rethrow them as JavaScript exceptions before returning from the callback,
+// wrapping in an Napi::Error as needed.
+template <typename Callable>
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS_ALL
+inline void WrapVoidCallback(napi_env env, Callable callback) {
+#else
+inline void WrapVoidCallback(napi_env, Callable callback) {
+#endif
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+  try {
+    callback();
+  } catch (const Error& e) {
+    e.ThrowAsJavaScriptException();
+  }
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS_ALL
+  catch (const std::exception& e) {
+    Napi::Error::New(env, e.what()).ThrowAsJavaScriptException();
+  } catch (...) {
+    Napi::Error::New(env, "A native exception was thrown")
+        .ThrowAsJavaScriptException();
+  }
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS_ALL
+#else
+  // When C++ exceptions are disabled, there is no need to catch and rethrow C++
+  // exceptions. JS errors should be thrown with
+  // `Error::ThrowAsJavaScriptException`.
+  callback();
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+}
+
+template <typename Callable, typename Return>
+struct CallbackData {
+  static inline napi_value Wrapper(napi_env env, napi_callback_info info) {
+    return details::WrapCallback(env, [&] {
+      CallbackInfo callbackInfo(env, info);
+      CallbackData* callbackData =
+          static_cast<CallbackData*>(callbackInfo.Data());
+      callbackInfo.SetData(callbackData->data);
+      return callbackData->callback(callbackInfo);
+    });
+  }
+
+  Callable callback;
+  void* data;
+};
+
+template <typename Callable>
+struct CallbackData<Callable, void> {
+  static inline napi_value Wrapper(napi_env env, napi_callback_info info) {
+    return details::WrapCallback(env, [&] {
+      CallbackInfo callbackInfo(env, info);
+      CallbackData* callbackData =
+          static_cast<CallbackData*>(callbackInfo.Data());
+      callbackInfo.SetData(callbackData->data);
+      callbackData->callback(callbackInfo);
+      return nullptr;
+    });
+  }
+
+  Callable callback;
+  void* data;
+};
+
+template <void (*Callback)(const CallbackInfo& info)>
+napi_value TemplatedVoidCallback(napi_env env,
+                                 napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo cbInfo(env, info);
+    Callback(cbInfo);
+    return nullptr;
+  });
+}
+
+template <Napi::Value (*Callback)(const CallbackInfo& info)>
+napi_value TemplatedCallback(napi_env env,
+                             napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo cbInfo(env, info);
+    // MSVC requires to copy 'Callback' function pointer to a local variable
+    // before invoking it.
+    auto callback = Callback;
+    return callback(cbInfo);
+  });
+}
+
+template <typename T,
+          Napi::Value (T::*UnwrapCallback)(const CallbackInfo& info)>
+napi_value TemplatedInstanceCallback(napi_env env,
+                                     napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo cbInfo(env, info);
+    T* instance = T::Unwrap(cbInfo.This().As<Object>());
+    return instance ? (instance->*UnwrapCallback)(cbInfo) : Napi::Value();
+  });
+}
+
+template <typename T, void (T::*UnwrapCallback)(const CallbackInfo& info)>
+napi_value TemplatedInstanceVoidCallback(napi_env env, napi_callback_info info)
+    NAPI_NOEXCEPT {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo cbInfo(env, info);
+    T* instance = T::Unwrap(cbInfo.This().As<Object>());
+    if (instance) (instance->*UnwrapCallback)(cbInfo);
+    return nullptr;
+  });
+}
+
+template <typename T, typename Finalizer, typename Hint = void>
+struct FinalizeData {
+#ifdef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+  template <typename F = Finalizer,
+            typename = std::enable_if_t<
+                std::is_invocable_v<F, node_addon_api_basic_env, T*>>>
+#endif
+  static inline void Wrapper(node_addon_api_basic_env env,
+                             void* data,
+                             void* finalizeHint) NAPI_NOEXCEPT {
+    WrapVoidCallback([&] {
+      FinalizeData* finalizeData = static_cast<FinalizeData*>(finalizeHint);
+      finalizeData->callback(env, static_cast<T*>(data));
+      delete finalizeData;
+    });
+  }
+
+#ifdef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+  template <typename F = Finalizer,
+            typename = std::enable_if_t<
+                !std::is_invocable_v<F, node_addon_api_basic_env, T*>>,
+            typename = void>
+  static inline void Wrapper(node_addon_api_basic_env env,
+                             void* data,
+                             void* finalizeHint) NAPI_NOEXCEPT {
+#ifdef NODE_ADDON_API_REQUIRE_BASIC_FINALIZERS
+    static_assert(false,
+                  "NODE_ADDON_API_REQUIRE_BASIC_FINALIZERS defined: Finalizer "
+                  "must be basic.");
+#endif
+    napi_status status =
+        node_api_post_finalizer(env, WrapperGC, data, finalizeHint);
+    NAPI_FATAL_IF_FAILED(
+        status, "FinalizeData::Wrapper", "node_api_post_finalizer failed");
+  }
+#endif
+
+#ifdef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+  template <typename F = Finalizer,
+            typename = std::enable_if_t<
+                std::is_invocable_v<F, node_addon_api_basic_env, T*, Hint*>>>
+#endif
+  static inline void WrapperWithHint(node_addon_api_basic_env env,
+                                     void* data,
+                                     void* finalizeHint) NAPI_NOEXCEPT {
+    WrapVoidCallback([&] {
+      FinalizeData* finalizeData = static_cast<FinalizeData*>(finalizeHint);
+      finalizeData->callback(env, static_cast<T*>(data), finalizeData->hint);
+      delete finalizeData;
+    });
+  }
+
+#ifdef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+  template <typename F = Finalizer,
+            typename = std::enable_if_t<
+                !std::is_invocable_v<F, node_addon_api_basic_env, T*, Hint*>>,
+            typename = void>
+  static inline void WrapperWithHint(node_addon_api_basic_env env,
+                                     void* data,
+                                     void* finalizeHint) NAPI_NOEXCEPT {
+#ifdef NODE_ADDON_API_REQUIRE_BASIC_FINALIZERS
+    static_assert(false,
+                  "NODE_ADDON_API_REQUIRE_BASIC_FINALIZERS defined: Finalizer "
+                  "must be basic.");
+#endif
+    napi_status status =
+        node_api_post_finalizer(env, WrapperGCWithHint, data, finalizeHint);
+    NAPI_FATAL_IF_FAILED(
+        status, "FinalizeData::Wrapper", "node_api_post_finalizer failed");
+  }
+#endif
+
+  static inline void WrapperGCWithoutData(napi_env env,
+                                          void* /*data*/,
+                                          void* finalizeHint) NAPI_NOEXCEPT {
+    WrapVoidCallback(env, [&] {
+      FinalizeData* finalizeData = static_cast<FinalizeData*>(finalizeHint);
+      finalizeData->callback(env);
+      delete finalizeData;
+    });
+  }
+
+  static inline void WrapperGC(napi_env env,
+                               void* data,
+                               void* finalizeHint) NAPI_NOEXCEPT {
+    WrapVoidCallback(env, [&] {
+      FinalizeData* finalizeData = static_cast<FinalizeData*>(finalizeHint);
+      finalizeData->callback(env, static_cast<T*>(data));
+      delete finalizeData;
+    });
+  }
+
+  static inline void WrapperGCWithHint(napi_env env,
+                                       void* data,
+                                       void* finalizeHint) NAPI_NOEXCEPT {
+    WrapVoidCallback(env, [&] {
+      FinalizeData* finalizeData = static_cast<FinalizeData*>(finalizeHint);
+      finalizeData->callback(env, static_cast<T*>(data), finalizeData->hint);
+      delete finalizeData;
+    });
+  }
+
+  Finalizer callback;
+  Hint* hint;
+};
+
+#if (NAPI_VERSION > 3 && NAPI_HAS_THREADS)
+template <typename ContextType = void,
+          typename Finalizer = std::function<void(Env, void*, ContextType*)>,
+          typename FinalizerDataType = void>
+struct ThreadSafeFinalize {
+  static inline void Wrapper(napi_env env,
+                             void* rawFinalizeData,
+                             void* /* rawContext */) {
+    if (rawFinalizeData == nullptr) return;
+
+    ThreadSafeFinalize* finalizeData =
+        static_cast<ThreadSafeFinalize*>(rawFinalizeData);
+    finalizeData->callback(Env(env));
+    delete finalizeData;
+  }
+
+  static inline void FinalizeWrapperWithData(napi_env env,
+                                             void* rawFinalizeData,
+                                             void* /* rawContext */) {
+    if (rawFinalizeData == nullptr) return;
+
+    ThreadSafeFinalize* finalizeData =
+        static_cast<ThreadSafeFinalize*>(rawFinalizeData);
+    finalizeData->callback(Env(env), finalizeData->data);
+    delete finalizeData;
+  }
+
+  static inline void FinalizeWrapperWithContext(napi_env env,
+                                                void* rawFinalizeData,
+                                                void* rawContext) {
+    if (rawFinalizeData == nullptr) return;
+
+    ThreadSafeFinalize* finalizeData =
+        static_cast<ThreadSafeFinalize*>(rawFinalizeData);
+    finalizeData->callback(Env(env), static_cast<ContextType*>(rawContext));
+    delete finalizeData;
+  }
+
+  static inline void FinalizeFinalizeWrapperWithDataAndContext(
+      napi_env env, void* rawFinalizeData, void* rawContext) {
+    if (rawFinalizeData == nullptr) return;
+
+    ThreadSafeFinalize* finalizeData =
+        static_cast<ThreadSafeFinalize*>(rawFinalizeData);
+    finalizeData->callback(
+        Env(env), finalizeData->data, static_cast<ContextType*>(rawContext));
+    delete finalizeData;
+  }
+
+  FinalizerDataType* data;
+  Finalizer callback;
+};
+
+template <typename ContextType, typename DataType, typename CallJs, CallJs call>
+inline typename std::enable_if<call != static_cast<CallJs>(nullptr)>::type
+CallJsWrapper(napi_env env, napi_value jsCallback, void* context, void* data) {
+  details::WrapVoidCallback(env, [&]() {
+    call(env,
+         Function(env, jsCallback),
+         static_cast<ContextType*>(context),
+         static_cast<DataType*>(data));
+  });
+}
+
+template <typename ContextType, typename DataType, typename CallJs, CallJs call>
+inline typename std::enable_if<call == static_cast<CallJs>(nullptr)>::type
+CallJsWrapper(napi_env env,
+              napi_value jsCallback,
+              void* /*context*/,
+              void* /*data*/) {
+  details::WrapVoidCallback(env, [&]() {
+    if (jsCallback != nullptr) {
+      Function(env, jsCallback).Call(0, nullptr);
+    }
+  });
+}
+
+#if NAPI_VERSION > 4
+
+template <typename CallbackType, typename TSFN>
+napi_value DefaultCallbackWrapper(napi_env /*env*/, std::nullptr_t /*cb*/) {
+  return nullptr;
+}
+
+template <typename CallbackType, typename TSFN>
+napi_value DefaultCallbackWrapper(napi_env /*env*/, Napi::Function cb) {
+  return cb;
+}
+
+#else
+template <typename CallbackType, typename TSFN>
+napi_value DefaultCallbackWrapper(napi_env env, Napi::Function cb) {
+  if (cb.IsEmpty()) {
+    return TSFN::EmptyFunctionFactory(env);
+  }
+  return cb;
+}
+#endif  // NAPI_VERSION > 4
+#endif  // NAPI_VERSION > 3 && NAPI_HAS_THREADS
+
+template <typename Getter, typename Setter>
+struct AccessorCallbackData {
+  static inline napi_value GetterWrapper(napi_env env,
+                                         napi_callback_info info) {
+    return details::WrapCallback(env, [&] {
+      CallbackInfo callbackInfo(env, info);
+      AccessorCallbackData* callbackData =
+          static_cast<AccessorCallbackData*>(callbackInfo.Data());
+      callbackInfo.SetData(callbackData->data);
+      return callbackData->getterCallback(callbackInfo);
+    });
+  }
+
+  static inline napi_value SetterWrapper(napi_env env,
+                                         napi_callback_info info) {
+    return details::WrapCallback(env, [&] {
+      CallbackInfo callbackInfo(env, info);
+      AccessorCallbackData* callbackData =
+          static_cast<AccessorCallbackData*>(callbackInfo.Data());
+      callbackInfo.SetData(callbackData->data);
+      callbackData->setterCallback(callbackInfo);
+      return nullptr;
+    });
+  }
+
+  Getter getterCallback;
+  Setter setterCallback;
+  void* data;
+};
+
+// Debugging-purpose C++-style variant of sprintf().
+inline std::string StringFormat(const char* format, ...) {
+  std::string result;
+  va_list args;
+  va_start(args, format);
+  int len = vsnprintf(nullptr, 0, format, args);
+  result.resize(len);
+  vsnprintf(&result[0], len + 1, format, args);
+  va_end(args);
+  return result;
+}
+
+template <typename T>
+class HasExtendedFinalizer {
+ private:
+  template <typename U, void (U::*)(Napi::Env)>
+  struct SFINAE {};
+  template <typename U>
+  static char test(SFINAE<U, &U::Finalize>*);
+  template <typename U>
+  static int test(...);
+
+ public:
+  static constexpr bool value = sizeof(test<T>(0)) == sizeof(char);
+};
+
+template <typename T>
+class HasBasicFinalizer {
+ private:
+  template <typename U, void (U::*)(Napi::BasicEnv)>
+  struct SFINAE {};
+  template <typename U>
+  static char test(SFINAE<U, &U::Finalize>*);
+  template <typename U>
+  static int test(...);
+
+ public:
+  static constexpr bool value = sizeof(test<T>(0)) == sizeof(char);
+};
+
+}  // namespace details
+
+#ifndef NODE_ADDON_API_DISABLE_DEPRECATED
+#include "napi-inl.deprecated.h"
+#endif  // !NODE_ADDON_API_DISABLE_DEPRECATED
+
+////////////////////////////////////////////////////////////////////////////////
+// Module registration
+////////////////////////////////////////////////////////////////////////////////
+
+// Register an add-on based on an initializer function.
+#define NODE_API_MODULE(modname, regfunc)                                      \
+  static napi_value __napi_##regfunc(napi_env env, napi_value exports) {       \
+    return Napi::RegisterModule(env, exports, regfunc);                        \
+  }                                                                            \
+  NAPI_MODULE(modname, __napi_##regfunc)
+
+// Register an add-on based on a subclass of `Addon<T>` with a custom Node.js
+// module name.
+#define NODE_API_NAMED_ADDON(modname, classname)                               \
+  static napi_value __napi_##classname(napi_env env, napi_value exports) {     \
+    return Napi::RegisterModule(env, exports, &classname::Init);               \
+  }                                                                            \
+  NAPI_MODULE(modname, __napi_##classname)
+
+// Register an add-on based on a subclass of `Addon<T>` with the Node.js module
+// name given by node-gyp from the `target_name` in binding.gyp.
+#define NODE_API_ADDON(classname)                                              \
+  NODE_API_NAMED_ADDON(NODE_GYP_MODULE_NAME, classname)
+
+// Adapt the NAPI_MODULE registration function:
+//  - Wrap the arguments in NAPI wrappers.
+//  - Catch any NAPI errors and rethrow as JS exceptions.
+inline napi_value RegisterModule(napi_env env,
+                                 napi_value exports,
+                                 ModuleRegisterCallback registerCallback) {
+  return details::WrapCallback(env, [&] {
+    return napi_value(
+        registerCallback(Napi::Env(env), Napi::Object(env, exports)));
+  });
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Maybe class
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T>
+bool Maybe<T>::IsNothing() const {
+  return !_has_value;
+}
+
+template <class T>
+bool Maybe<T>::IsJust() const {
+  return _has_value;
+}
+
+template <class T>
+void Maybe<T>::Check() const {
+  NAPI_CHECK(IsJust(), "Napi::Maybe::Check", "Maybe value is Nothing.");
+}
+
+template <class T>
+T Maybe<T>::Unwrap() const {
+  NAPI_CHECK(IsJust(), "Napi::Maybe::Unwrap", "Maybe value is Nothing.");
+  return _value;
+}
+
+template <class T>
+T Maybe<T>::UnwrapOr(const T& default_value) const {
+  return _has_value ? _value : default_value;
+}
+
+template <class T>
+bool Maybe<T>::UnwrapTo(T* out) const {
+  if (IsJust()) {
+    *out = _value;
+    return true;
+  };
+  return false;
+}
+
+template <class T>
+bool Maybe<T>::operator==(const Maybe& other) const {
+  return (IsJust() == other.IsJust()) &&
+         (!IsJust() || Unwrap() == other.Unwrap());
+}
+
+template <class T>
+bool Maybe<T>::operator!=(const Maybe& other) const {
+  return !operator==(other);
+}
+
+template <class T>
+Maybe<T>::Maybe() : _has_value(false) {}
+
+template <class T>
+Maybe<T>::Maybe(const T& t) : _has_value(true), _value(t) {}
+
+template <class T>
+inline Maybe<T> Nothing() {
+  return Maybe<T>();
+}
+
+template <class T>
+inline Maybe<T> Just(const T& t) {
+  return Maybe<T>(t);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// BasicEnv / Env class
+////////////////////////////////////////////////////////////////////////////////
+
+inline BasicEnv::BasicEnv(node_addon_api_basic_env env) : _env(env) {}
+
+inline BasicEnv::operator node_addon_api_basic_env() const {
+  return _env;
+}
+
+inline Env::Env(napi_env env) : BasicEnv(env) {}
+
+inline Env::operator napi_env() const {
+  return const_cast<napi_env>(_env);
+}
+
+inline Object Env::Global() const {
+  napi_value value;
+  napi_status status = napi_get_global(*this, &value);
+  NAPI_THROW_IF_FAILED(*this, status, Object());
+  return Object(*this, value);
+}
+
+inline Value Env::Undefined() const {
+  napi_value value;
+  napi_status status = napi_get_undefined(*this, &value);
+  NAPI_THROW_IF_FAILED(*this, status, Value());
+  return Value(*this, value);
+}
+
+inline Value Env::Null() const {
+  napi_value value;
+  napi_status status = napi_get_null(*this, &value);
+  NAPI_THROW_IF_FAILED(*this, status, Value());
+  return Value(*this, value);
+}
+
+inline bool Env::IsExceptionPending() const {
+  bool result;
+  napi_status status = napi_is_exception_pending(*this, &result);
+  if (status != napi_ok)
+    result = false;  // Checking for a pending exception shouldn't throw.
+  return result;
+}
+
+inline Error Env::GetAndClearPendingException() const {
+  napi_value value;
+  napi_status status = napi_get_and_clear_last_exception(*this, &value);
+  if (status != napi_ok) {
+    // Don't throw another exception when failing to get the exception!
+    return Error();
+  }
+  return Error(*this, value);
+}
+
+inline MaybeOrValue<Value> Env::RunScript(const char* utf8script) const {
+  String script = String::New(*this, utf8script);
+  return RunScript(script);
+}
+
+inline MaybeOrValue<Value> Env::RunScript(const std::string& utf8script) const {
+  return RunScript(utf8script.c_str());
+}
+
+inline MaybeOrValue<Value> Env::RunScript(String script) const {
+  napi_value result;
+  napi_status status = napi_run_script(*this, script, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      *this, status, Napi::Value(*this, result), Napi::Value);
+}
+
+#if NAPI_VERSION > 2
+template <typename Hook, typename Arg>
+void BasicEnv::CleanupHook<Hook, Arg>::Wrapper(void* data) NAPI_NOEXCEPT {
+  auto* cleanupData = static_cast<
+      typename Napi::BasicEnv::CleanupHook<Hook, Arg>::CleanupData*>(data);
+  cleanupData->hook();
+  delete cleanupData;
+}
+
+template <typename Hook, typename Arg>
+void BasicEnv::CleanupHook<Hook, Arg>::WrapperWithArg(void* data)
+    NAPI_NOEXCEPT {
+  auto* cleanupData = static_cast<
+      typename Napi::BasicEnv::CleanupHook<Hook, Arg>::CleanupData*>(data);
+  cleanupData->hook(static_cast<Arg*>(cleanupData->arg));
+  delete cleanupData;
+}
+#endif  // NAPI_VERSION > 2
+
+#if NAPI_VERSION > 5
+template <typename T, BasicEnv::Finalizer<T> fini>
+inline void BasicEnv::SetInstanceData(T* data) const {
+  napi_status status = napi_set_instance_data(
+      _env,
+      data,
+      [](napi_env env, void* data, void*) { fini(env, static_cast<T*>(data)); },
+      nullptr);
+  NAPI_FATAL_IF_FAILED(
+      status, "BasicEnv::SetInstanceData", "invalid arguments");
+}
+
+template <typename DataType,
+          typename HintType,
+          Napi::BasicEnv::FinalizerWithHint<DataType, HintType> fini>
+inline void BasicEnv::SetInstanceData(DataType* data, HintType* hint) const {
+  napi_status status = napi_set_instance_data(
+      _env,
+      data,
+      [](napi_env env, void* data, void* hint) {
+        fini(env, static_cast<DataType*>(data), static_cast<HintType*>(hint));
+      },
+      hint);
+  NAPI_FATAL_IF_FAILED(
+      status, "BasicEnv::SetInstanceData", "invalid arguments");
+}
+
+template <typename T>
+inline T* BasicEnv::GetInstanceData() const {
+  void* data = nullptr;
+
+  napi_status status = napi_get_instance_data(_env, &data);
+  NAPI_FATAL_IF_FAILED(
+      status, "BasicEnv::GetInstanceData", "invalid arguments");
+
+  return static_cast<T*>(data);
+}
+
+template <typename T>
+void BasicEnv::DefaultFini(Env, T* data) {
+  delete data;
+}
+
+template <typename DataType, typename HintType>
+void BasicEnv::DefaultFiniWithHint(Env, DataType* data, HintType*) {
+  delete data;
+}
+#endif  // NAPI_VERSION > 5
+
+#if NAPI_VERSION > 8
+inline const char* BasicEnv::GetModuleFileName() const {
+  const char* result;
+  napi_status status = node_api_get_module_file_name(_env, &result);
+  NAPI_FATAL_IF_FAILED(
+      status, "BasicEnv::GetModuleFileName", "invalid arguments");
+  return result;
+}
+#endif  // NAPI_VERSION > 8
+////////////////////////////////////////////////////////////////////////////////
+// Value class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Value::Value() : _env(nullptr), _value(nullptr) {}
+
+inline Value::Value(napi_env env, napi_value value)
+    : _env(env), _value(value) {}
+
+inline Value::operator napi_value() const {
+  return _value;
+}
+
+inline bool Value::operator==(const Value& other) const {
+  return StrictEquals(other);
+}
+
+inline bool Value::operator!=(const Value& other) const {
+  return !this->operator==(other);
+}
+
+inline bool Value::StrictEquals(const Value& other) const {
+  bool result;
+  napi_status status = napi_strict_equals(_env, *this, other, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline Napi::Env Value::Env() const {
+  return Napi::Env(_env);
+}
+
+inline bool Value::IsEmpty() const {
+  return _value == nullptr;
+}
+
+inline napi_valuetype Value::Type() const {
+  if (IsEmpty()) {
+    return napi_undefined;
+  }
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(_env, _value, &type);
+  NAPI_THROW_IF_FAILED(_env, status, napi_undefined);
+  return type;
+}
+
+inline bool Value::IsUndefined() const {
+  return Type() == napi_undefined;
+}
+
+inline bool Value::IsNull() const {
+  return Type() == napi_null;
+}
+
+inline bool Value::IsBoolean() const {
+  return Type() == napi_boolean;
+}
+
+inline bool Value::IsNumber() const {
+  return Type() == napi_number;
+}
+
+#if NAPI_VERSION > 5
+inline bool Value::IsBigInt() const {
+  return Type() == napi_bigint;
+}
+#endif  // NAPI_VERSION > 5
+
+#if (NAPI_VERSION > 4)
+inline bool Value::IsDate() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_date(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+#endif
+
+inline bool Value::IsString() const {
+  return Type() == napi_string;
+}
+
+inline bool Value::IsSymbol() const {
+  return Type() == napi_symbol;
+}
+
+inline bool Value::IsArray() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_array(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsArrayBuffer() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_arraybuffer(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsTypedArray() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_typedarray(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsObject() const {
+  return Type() == napi_object || IsFunction();
+}
+
+inline bool Value::IsFunction() const {
+  return Type() == napi_function;
+}
+
+inline bool Value::IsPromise() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_promise(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsDataView() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_dataview(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsBuffer() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_buffer(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsExternal() const {
+  return Type() == napi_external;
+}
+
+template <typename T>
+inline T Value::As() const {
+#ifdef NODE_ADDON_API_ENABLE_TYPE_CHECK_ON_AS
+  T::CheckCast(_env, _value);
+#endif
+  return T(_env, _value);
+}
+
+template <typename T>
+inline T Value::UnsafeAs() const {
+  return T(_env, _value);
+}
+
+// static
+inline void Value::CheckCast(napi_env /* env */, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Value::CheckCast", "empty value");
+}
+
+inline MaybeOrValue<Boolean> Value::ToBoolean() const {
+  napi_value result;
+  napi_status status = napi_coerce_to_bool(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Boolean(_env, result), Napi::Boolean);
+}
+
+inline MaybeOrValue<Number> Value::ToNumber() const {
+  napi_value result;
+  napi_status status = napi_coerce_to_number(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Number(_env, result), Napi::Number);
+}
+
+inline MaybeOrValue<String> Value::ToString() const {
+  napi_value result;
+  napi_status status = napi_coerce_to_string(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::String(_env, result), Napi::String);
+}
+
+inline MaybeOrValue<Object> Value::ToObject() const {
+  napi_value result;
+  napi_status status = napi_coerce_to_object(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Object(_env, result), Napi::Object);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Boolean class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Boolean Boolean::New(napi_env env, bool val) {
+  napi_value value;
+  napi_status status = napi_get_boolean(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, Boolean());
+  return Boolean(env, value);
+}
+
+inline void Boolean::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Boolean::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Boolean::CheckCast", "napi_typeof failed");
+  NAPI_INTERNAL_CHECK_EQ(type, napi_boolean, "%d", "Boolean::CheckCast");
+}
+
+inline Boolean::Boolean() : Napi::Value() {}
+
+inline Boolean::Boolean(napi_env env, napi_value value)
+    : Napi::Value(env, value) {}
+
+inline Boolean::operator bool() const {
+  return Value();
+}
+
+inline bool Boolean::Value() const {
+  bool result;
+  napi_status status = napi_get_value_bool(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Number class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Number Number::New(napi_env env, double val) {
+  napi_value value;
+  napi_status status = napi_create_double(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, Number());
+  return Number(env, value);
+}
+
+inline void Number::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Number::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Number::CheckCast", "napi_typeof failed");
+  NAPI_INTERNAL_CHECK_EQ(type, napi_number, "%d", "Number::CheckCast");
+}
+
+inline Number::Number() : Value() {}
+
+inline Number::Number(napi_env env, napi_value value) : Value(env, value) {}
+
+inline Number::operator int32_t() const {
+  return Int32Value();
+}
+
+inline Number::operator uint32_t() const {
+  return Uint32Value();
+}
+
+inline Number::operator int64_t() const {
+  return Int64Value();
+}
+
+inline Number::operator float() const {
+  return FloatValue();
+}
+
+inline Number::operator double() const {
+  return DoubleValue();
+}
+
+inline int32_t Number::Int32Value() const {
+  int32_t result;
+  napi_status status = napi_get_value_int32(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline uint32_t Number::Uint32Value() const {
+  uint32_t result;
+  napi_status status = napi_get_value_uint32(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline int64_t Number::Int64Value() const {
+  int64_t result;
+  napi_status status = napi_get_value_int64(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline float Number::FloatValue() const {
+  return static_cast<float>(DoubleValue());
+}
+
+inline double Number::DoubleValue() const {
+  double result;
+  napi_status status = napi_get_value_double(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+#if NAPI_VERSION > 5
+////////////////////////////////////////////////////////////////////////////////
+// BigInt Class
+////////////////////////////////////////////////////////////////////////////////
+
+inline BigInt BigInt::New(napi_env env, int64_t val) {
+  napi_value value;
+  napi_status status = napi_create_bigint_int64(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, BigInt());
+  return BigInt(env, value);
+}
+
+inline BigInt BigInt::New(napi_env env, uint64_t val) {
+  napi_value value;
+  napi_status status = napi_create_bigint_uint64(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, BigInt());
+  return BigInt(env, value);
+}
+
+inline BigInt BigInt::New(napi_env env,
+                          int sign_bit,
+                          size_t word_count,
+                          const uint64_t* words) {
+  napi_value value;
+  napi_status status =
+      napi_create_bigint_words(env, sign_bit, word_count, words, &value);
+  NAPI_THROW_IF_FAILED(env, status, BigInt());
+  return BigInt(env, value);
+}
+
+inline void BigInt::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "BigInt::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "BigInt::CheckCast", "napi_typeof failed");
+  NAPI_INTERNAL_CHECK_EQ(type, napi_bigint, "%d", "BigInt::CheckCast");
+}
+
+inline BigInt::BigInt() : Value() {}
+
+inline BigInt::BigInt(napi_env env, napi_value value) : Value(env, value) {}
+
+inline int64_t BigInt::Int64Value(bool* lossless) const {
+  int64_t result;
+  napi_status status =
+      napi_get_value_bigint_int64(_env, _value, &result, lossless);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline uint64_t BigInt::Uint64Value(bool* lossless) const {
+  uint64_t result;
+  napi_status status =
+      napi_get_value_bigint_uint64(_env, _value, &result, lossless);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline size_t BigInt::WordCount() const {
+  size_t word_count;
+  napi_status status =
+      napi_get_value_bigint_words(_env, _value, nullptr, &word_count, nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return word_count;
+}
+
+inline void BigInt::ToWords(int* sign_bit,
+                            size_t* word_count,
+                            uint64_t* words) {
+  napi_status status =
+      napi_get_value_bigint_words(_env, _value, sign_bit, word_count, words);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+#endif  // NAPI_VERSION > 5
+
+#if (NAPI_VERSION > 4)
+////////////////////////////////////////////////////////////////////////////////
+// Date Class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Date Date::New(napi_env env, double val) {
+  napi_value value;
+  napi_status status = napi_create_date(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, Date());
+  return Date(env, value);
+}
+
+inline void Date::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Date::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_date(env, value, &result);
+  NAPI_CHECK(status == napi_ok, "Date::CheckCast", "napi_is_date failed");
+  NAPI_CHECK(result, "Date::CheckCast", "value is not date");
+}
+
+inline Date::Date() : Value() {}
+
+inline Date::Date(napi_env env, napi_value value) : Value(env, value) {}
+
+inline Date::operator double() const {
+  return ValueOf();
+}
+
+inline double Date::ValueOf() const {
+  double result;
+  napi_status status = napi_get_date_value(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// Name class
+////////////////////////////////////////////////////////////////////////////////
+inline void Name::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Name::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Name::CheckCast", "napi_typeof failed");
+  NAPI_INTERNAL_CHECK(type == napi_string || type == napi_symbol,
+                      "Name::CheckCast",
+                      "value is not napi_string or napi_symbol, got %d.",
+                      type);
+}
+
+inline Name::Name() : Value() {}
+
+inline Name::Name(napi_env env, napi_value value) : Value(env, value) {}
+
+////////////////////////////////////////////////////////////////////////////////
+// String class
+////////////////////////////////////////////////////////////////////////////////
+
+inline String String::New(napi_env env, const std::string& val) {
+  return String::New(env, val.c_str(), val.size());
+}
+
+inline String String::New(napi_env env, const std::u16string& val) {
+  return String::New(env, val.c_str(), val.size());
+}
+
+inline String String::New(napi_env env, const char* val) {
+  // TODO(@gabrielschulhof) Remove if-statement when core's error handling is
+  // available in all supported versions.
+  if (val == nullptr) {
+    // Throw an error that looks like it came from core.
+    NAPI_THROW_IF_FAILED(env, napi_invalid_arg, String());
+  }
+  napi_value value;
+  napi_status status =
+      napi_create_string_utf8(env, val, std::strlen(val), &value);
+  NAPI_THROW_IF_FAILED(env, status, String());
+  return String(env, value);
+}
+
+inline String String::New(napi_env env, const char16_t* val) {
+  napi_value value;
+  // TODO(@gabrielschulhof) Remove if-statement when core's error handling is
+  // available in all supported versions.
+  if (val == nullptr) {
+    // Throw an error that looks like it came from core.
+    NAPI_THROW_IF_FAILED(env, napi_invalid_arg, String());
+  }
+  napi_status status =
+      napi_create_string_utf16(env, val, std::u16string(val).size(), &value);
+  NAPI_THROW_IF_FAILED(env, status, String());
+  return String(env, value);
+}
+
+inline String String::New(napi_env env, const char* val, size_t length) {
+  napi_value value;
+  napi_status status = napi_create_string_utf8(env, val, length, &value);
+  NAPI_THROW_IF_FAILED(env, status, String());
+  return String(env, value);
+}
+
+inline String String::New(napi_env env, const char16_t* val, size_t length) {
+  napi_value value;
+  napi_status status = napi_create_string_utf16(env, val, length, &value);
+  NAPI_THROW_IF_FAILED(env, status, String());
+  return String(env, value);
+}
+
+inline void String::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "String::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "String::CheckCast", "napi_typeof failed");
+  NAPI_INTERNAL_CHECK_EQ(type, napi_string, "%d", "String::CheckCast");
+}
+
+inline String::String() : Name() {}
+
+inline String::String(napi_env env, napi_value value) : Name(env, value) {}
+
+inline String::operator std::string() const {
+  return Utf8Value();
+}
+
+inline String::operator std::u16string() const {
+  return Utf16Value();
+}
+
+inline std::string String::Utf8Value() const {
+  size_t length;
+  napi_status status =
+      napi_get_value_string_utf8(_env, _value, nullptr, 0, &length);
+  NAPI_THROW_IF_FAILED(_env, status, "");
+
+  std::string value;
+  value.reserve(length + 1);
+  value.resize(length);
+  status = napi_get_value_string_utf8(
+      _env, _value, &value[0], value.capacity(), nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, "");
+  return value;
+}
+
+inline std::u16string String::Utf16Value() const {
+  size_t length;
+  napi_status status =
+      napi_get_value_string_utf16(_env, _value, nullptr, 0, &length);
+  NAPI_THROW_IF_FAILED(_env, status, NAPI_WIDE_TEXT(""));
+
+  std::u16string value;
+  value.reserve(length + 1);
+  value.resize(length);
+  status = napi_get_value_string_utf16(
+      _env, _value, &value[0], value.capacity(), nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, NAPI_WIDE_TEXT(""));
+  return value;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Symbol class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Symbol Symbol::New(napi_env env, const char* description) {
+  napi_value descriptionValue = description != nullptr
+                                    ? String::New(env, description)
+                                    : static_cast<napi_value>(nullptr);
+  return Symbol::New(env, descriptionValue);
+}
+
+inline Symbol Symbol::New(napi_env env, const std::string& description) {
+  napi_value descriptionValue = String::New(env, description);
+  return Symbol::New(env, descriptionValue);
+}
+
+inline Symbol Symbol::New(napi_env env, String description) {
+  napi_value descriptionValue = description;
+  return Symbol::New(env, descriptionValue);
+}
+
+inline Symbol Symbol::New(napi_env env, napi_value description) {
+  napi_value value;
+  napi_status status = napi_create_symbol(env, description, &value);
+  NAPI_THROW_IF_FAILED(env, status, Symbol());
+  return Symbol(env, value);
+}
+
+inline MaybeOrValue<Symbol> Symbol::WellKnown(napi_env env,
+                                              const std::string& name) {
+  // No need to check if the return value is a symbol or undefined.
+  // Well known symbols are definite and it is an develop time error
+  // if the symbol does not exist.
+#if defined(NODE_ADDON_API_ENABLE_MAYBE)
+  Value symbol_obj;
+  Value symbol_value;
+  if (Napi::Env(env).Global().Get("Symbol").UnwrapTo(&symbol_obj) &&
+      symbol_obj.As<Object>().Get(name).UnwrapTo(&symbol_value)) {
+    return Just<Symbol>(symbol_value.UnsafeAs<Symbol>());
+  }
+  return Nothing<Symbol>();
+#else
+  return Napi::Env(env)
+      .Global()
+      .Get("Symbol")
+      .As<Object>()
+      .Get(name)
+      .UnsafeAs<Symbol>();
+#endif
+}
+
+inline MaybeOrValue<Symbol> Symbol::For(napi_env env,
+                                        const std::string& description) {
+  napi_value descriptionValue = String::New(env, description);
+  return Symbol::For(env, descriptionValue);
+}
+
+inline MaybeOrValue<Symbol> Symbol::For(napi_env env, const char* description) {
+  napi_value descriptionValue = String::New(env, description);
+  return Symbol::For(env, descriptionValue);
+}
+
+inline MaybeOrValue<Symbol> Symbol::For(napi_env env, String description) {
+  return Symbol::For(env, static_cast<napi_value>(description));
+}
+
+inline MaybeOrValue<Symbol> Symbol::For(napi_env env, napi_value description) {
+#if defined(NODE_ADDON_API_ENABLE_MAYBE)
+  Value symbol_obj;
+  Value symbol_for_value;
+  Value symbol_value;
+  if (Napi::Env(env).Global().Get("Symbol").UnwrapTo(&symbol_obj) &&
+      symbol_obj.As<Object>().Get("for").UnwrapTo(&symbol_for_value) &&
+      symbol_for_value.As<Function>()
+          .Call(symbol_obj, {description})
+          .UnwrapTo(&symbol_value)) {
+    return Just<Symbol>(symbol_value.As<Symbol>());
+  }
+  return Nothing<Symbol>();
+#else
+  Object symbol_obj = Napi::Env(env).Global().Get("Symbol").As<Object>();
+  return symbol_obj.Get("for")
+      .As<Function>()
+      .Call(symbol_obj, {description})
+      .As<Symbol>();
+#endif
+}
+
+inline void Symbol::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Symbol::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Symbol::CheckCast", "napi_typeof failed");
+  NAPI_INTERNAL_CHECK_EQ(type, napi_symbol, "%d", "Symbol::CheckCast");
+}
+
+inline Symbol::Symbol() : Name() {}
+
+inline Symbol::Symbol(napi_env env, napi_value value) : Name(env, value) {}
+
+////////////////////////////////////////////////////////////////////////////////
+// Automagic value creation
+////////////////////////////////////////////////////////////////////////////////
+
+namespace details {
+template <typename T>
+struct vf_number {
+  static Number From(napi_env env, T value) {
+    return Number::New(env, static_cast<double>(value));
+  }
+};
+
+template <>
+struct vf_number<bool> {
+  static Boolean From(napi_env env, bool value) {
+    return Boolean::New(env, value);
+  }
+};
+
+struct vf_utf8_charp {
+  static String From(napi_env env, const char* value) {
+    return String::New(env, value);
+  }
+};
+
+struct vf_utf16_charp {
+  static String From(napi_env env, const char16_t* value) {
+    return String::New(env, value);
+  }
+};
+struct vf_utf8_string {
+  static String From(napi_env env, const std::string& value) {
+    return String::New(env, value);
+  }
+};
+
+struct vf_utf16_string {
+  static String From(napi_env env, const std::u16string& value) {
+    return String::New(env, value);
+  }
+};
+
+template <typename T>
+struct vf_fallback {
+  static Value From(napi_env env, const T& value) { return Value(env, value); }
+};
+
+template <typename...>
+struct disjunction : std::false_type {};
+template <typename B>
+struct disjunction<B> : B {};
+template <typename B, typename... Bs>
+struct disjunction<B, Bs...>
+    : std::conditional<bool(B::value), B, disjunction<Bs...>>::type {};
+
+template <typename T>
+struct can_make_string
+    : disjunction<typename std::is_convertible<T, const char*>::type,
+                  typename std::is_convertible<T, const char16_t*>::type,
+                  typename std::is_convertible<T, std::string>::type,
+                  typename std::is_convertible<T, std::u16string>::type> {};
+}  // namespace details
+
+template <typename T>
+Value Value::From(napi_env env, const T& value) {
+  using Helper = typename std::conditional<
+      std::is_integral<T>::value || std::is_floating_point<T>::value,
+      details::vf_number<T>,
+      typename std::conditional<details::can_make_string<T>::value,
+                                String,
+                                details::vf_fallback<T>>::type>::type;
+  return Helper::From(env, value);
+}
+
+template <typename T>
+String String::From(napi_env env, const T& value) {
+  struct Dummy {};
+  using Helper = typename std::conditional<
+      std::is_convertible<T, const char*>::value,
+      details::vf_utf8_charp,
+      typename std::conditional<
+          std::is_convertible<T, const char16_t*>::value,
+          details::vf_utf16_charp,
+          typename std::conditional<
+              std::is_convertible<T, std::string>::value,
+              details::vf_utf8_string,
+              typename std::conditional<
+                  std::is_convertible<T, std::u16string>::value,
+                  details::vf_utf16_string,
+                  Dummy>::type>::type>::type>::type;
+  return Helper::From(env, value);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TypeTaggable class
+////////////////////////////////////////////////////////////////////////////////
+
+inline TypeTaggable::TypeTaggable() : Value() {}
+
+inline TypeTaggable::TypeTaggable(napi_env _env, napi_value _value)
+    : Value(_env, _value) {}
+
+#if NAPI_VERSION >= 8
+
+inline void TypeTaggable::TypeTag(const napi_type_tag* type_tag) const {
+  napi_status status = napi_type_tag_object(_env, _value, type_tag);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline bool TypeTaggable::CheckTypeTag(const napi_type_tag* type_tag) const {
+  bool result;
+  napi_status status =
+      napi_check_object_type_tag(_env, _value, type_tag, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+#endif  // NAPI_VERSION >= 8
+
+////////////////////////////////////////////////////////////////////////////////
+// Object class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename Key>
+inline Object::PropertyLValue<Key>::operator Value() const {
+  MaybeOrValue<Value> val = Object(_env, _object).Get(_key);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  return val.Unwrap();
+#else
+  return val;
+#endif
+}
+
+template <typename Key>
+template <typename ValueType>
+inline Object::PropertyLValue<Key>& Object::PropertyLValue<Key>::operator=(
+    ValueType value) {
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  MaybeOrValue<bool> result =
+#endif
+      Object(_env, _object).Set(_key, value);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  result.Unwrap();
+#endif
+  return *this;
+}
+
+template <typename Key>
+inline Value Object::PropertyLValue<Key>::AsValue() const {
+  return Value(*this);
+}
+
+template <typename Key>
+inline Object::PropertyLValue<Key>::PropertyLValue(Object object, Key key)
+    : _env(object.Env()), _object(object), _key(key) {}
+
+inline Object Object::New(napi_env env) {
+  napi_value value;
+  napi_status status = napi_create_object(env, &value);
+  NAPI_THROW_IF_FAILED(env, status, Object());
+  return Object(env, value);
+}
+
+inline void Object::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Object::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Object::CheckCast", "napi_typeof failed");
+  NAPI_INTERNAL_CHECK(type == napi_object || type == napi_function,
+                      "Object::CheckCast",
+                      "Expect napi_object or napi_function, but got %d.",
+                      type);
+}
+
+inline Object::Object() : TypeTaggable() {}
+
+inline Object::Object(napi_env env, napi_value value)
+    : TypeTaggable(env, value) {}
+
+inline Object::PropertyLValue<std::string> Object::operator[](
+    const char* utf8name) {
+  return PropertyLValue<std::string>(*this, utf8name);
+}
+
+inline Object::PropertyLValue<std::string> Object::operator[](
+    const std::string& utf8name) {
+  return PropertyLValue<std::string>(*this, utf8name);
+}
+
+inline Object::PropertyLValue<uint32_t> Object::operator[](uint32_t index) {
+  return PropertyLValue<uint32_t>(*this, index);
+}
+
+inline Object::PropertyLValue<Value> Object::operator[](Value index) const {
+  return PropertyLValue<Value>(*this, index);
+}
+
+inline MaybeOrValue<Value> Object::operator[](const char* utf8name) const {
+  return Get(utf8name);
+}
+
+inline MaybeOrValue<Value> Object::operator[](
+    const std::string& utf8name) const {
+  return Get(utf8name);
+}
+
+inline MaybeOrValue<Value> Object::operator[](uint32_t index) const {
+  return Get(index);
+}
+
+inline MaybeOrValue<bool> Object::Has(napi_value key) const {
+  bool result;
+  napi_status status = napi_has_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Has(Value key) const {
+  bool result;
+  napi_status status = napi_has_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Has(const char* utf8name) const {
+  bool result;
+  napi_status status = napi_has_named_property(_env, _value, utf8name, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Has(const std::string& utf8name) const {
+  return Has(utf8name.c_str());
+}
+
+inline MaybeOrValue<bool> Object::HasOwnProperty(napi_value key) const {
+  bool result;
+  napi_status status = napi_has_own_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::HasOwnProperty(Value key) const {
+  bool result;
+  napi_status status = napi_has_own_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::HasOwnProperty(const char* utf8name) const {
+  napi_value key;
+  napi_status status =
+      napi_create_string_utf8(_env, utf8name, std::strlen(utf8name), &key);
+  NAPI_MAYBE_THROW_IF_FAILED(_env, status, bool);
+  return HasOwnProperty(key);
+}
+
+inline MaybeOrValue<bool> Object::HasOwnProperty(
+    const std::string& utf8name) const {
+  return HasOwnProperty(utf8name.c_str());
+}
+
+inline MaybeOrValue<Value> Object::Get(napi_value key) const {
+  napi_value result;
+  napi_status status = napi_get_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Value(_env, result), Value);
+}
+
+inline MaybeOrValue<Value> Object::Get(Value key) const {
+  napi_value result;
+  napi_status status = napi_get_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Value(_env, result), Value);
+}
+
+inline MaybeOrValue<Value> Object::Get(const char* utf8name) const {
+  napi_value result;
+  napi_status status = napi_get_named_property(_env, _value, utf8name, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Value(_env, result), Value);
+}
+
+inline MaybeOrValue<Value> Object::Get(const std::string& utf8name) const {
+  return Get(utf8name.c_str());
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(napi_value key,
+                                      const ValueType& value) const {
+  napi_status status =
+      napi_set_property(_env, _value, key, Value::From(_env, value));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(Value key, const ValueType& value) const {
+  napi_status status =
+      napi_set_property(_env, _value, key, Value::From(_env, value));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(const char* utf8name,
+                                      const ValueType& value) const {
+  napi_status status =
+      napi_set_named_property(_env, _value, utf8name, Value::From(_env, value));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(const std::string& utf8name,
+                                      const ValueType& value) const {
+  return Set(utf8name.c_str(), value);
+}
+
+inline MaybeOrValue<bool> Object::Delete(napi_value key) const {
+  bool result;
+  napi_status status = napi_delete_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Delete(Value key) const {
+  bool result;
+  napi_status status = napi_delete_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Delete(const char* utf8name) const {
+  return Delete(String::New(_env, utf8name));
+}
+
+inline MaybeOrValue<bool> Object::Delete(const std::string& utf8name) const {
+  return Delete(String::New(_env, utf8name));
+}
+
+inline MaybeOrValue<bool> Object::Has(uint32_t index) const {
+  bool result;
+  napi_status status = napi_has_element(_env, _value, index, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<Value> Object::Get(uint32_t index) const {
+  napi_value value;
+  napi_status status = napi_get_element(_env, _value, index, &value);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Value(_env, value), Value);
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(uint32_t index,
+                                      const ValueType& value) const {
+  napi_status status =
+      napi_set_element(_env, _value, index, Value::From(_env, value));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::Delete(uint32_t index) const {
+  bool result;
+  napi_status status = napi_delete_element(_env, _value, index, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<Array> Object::GetPropertyNames() const {
+  napi_value result;
+  napi_status status = napi_get_property_names(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Array(_env, result), Array);
+}
+
+inline MaybeOrValue<bool> Object::DefineProperty(
+    const PropertyDescriptor& property) const {
+  napi_status status = napi_define_properties(
+      _env,
+      _value,
+      1,
+      reinterpret_cast<const napi_property_descriptor*>(&property));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::DefineProperties(
+    const std::initializer_list<PropertyDescriptor>& properties) const {
+  napi_status status = napi_define_properties(
+      _env,
+      _value,
+      properties.size(),
+      reinterpret_cast<const napi_property_descriptor*>(properties.begin()));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::DefineProperties(
+    const std::vector<PropertyDescriptor>& properties) const {
+  napi_status status = napi_define_properties(
+      _env,
+      _value,
+      properties.size(),
+      reinterpret_cast<const napi_property_descriptor*>(properties.data()));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::InstanceOf(
+    const Function& constructor) const {
+  bool result;
+  napi_status status = napi_instanceof(_env, _value, constructor, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+template <typename Finalizer, typename T>
+inline void Object::AddFinalizer(Finalizer finalizeCallback, T* data) const {
+  details::FinalizeData<T, Finalizer>* finalizeData =
+      new details::FinalizeData<T, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+  napi_status status =
+      details::AttachData<T, details::FinalizeData<T, Finalizer>::Wrapper>(
+          _env, *this, data, finalizeData);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+template <typename Finalizer, typename T, typename Hint>
+inline void Object::AddFinalizer(Finalizer finalizeCallback,
+                                 T* data,
+                                 Hint* finalizeHint) const {
+  details::FinalizeData<T, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<T, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+  napi_status status = details::
+      AttachData<T, details::FinalizeData<T, Finalizer, Hint>::WrapperWithHint>(
+          _env, *this, data, finalizeData);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+inline Object::const_iterator::const_iterator(const Object* object,
+                                              const Type type) {
+  _object = object;
+  _keys = object->GetPropertyNames();
+  _index = type == Type::BEGIN ? 0 : _keys.Length();
+}
+
+inline Object::const_iterator Napi::Object::begin() const {
+  const_iterator it(this, Object::const_iterator::Type::BEGIN);
+  return it;
+}
+
+inline Object::const_iterator Napi::Object::end() const {
+  const_iterator it(this, Object::const_iterator::Type::END);
+  return it;
+}
+
+inline Object::const_iterator& Object::const_iterator::operator++() {
+  ++_index;
+  return *this;
+}
+
+inline bool Object::const_iterator::operator==(
+    const const_iterator& other) const {
+  return _index == other._index;
+}
+
+inline bool Object::const_iterator::operator!=(
+    const const_iterator& other) const {
+  return _index != other._index;
+}
+
+inline const std::pair<Value, Object::PropertyLValue<Value>>
+Object::const_iterator::operator*() const {
+  const Value key = _keys[_index];
+  const PropertyLValue<Value> value = (*_object)[key];
+  return {key, value};
+}
+
+inline Object::iterator::iterator(Object* object, const Type type) {
+  _object = object;
+  _keys = object->GetPropertyNames();
+  _index = type == Type::BEGIN ? 0 : _keys.Length();
+}
+
+inline Object::iterator Napi::Object::begin() {
+  iterator it(this, Object::iterator::Type::BEGIN);
+  return it;
+}
+
+inline Object::iterator Napi::Object::end() {
+  iterator it(this, Object::iterator::Type::END);
+  return it;
+}
+
+inline Object::iterator& Object::iterator::operator++() {
+  ++_index;
+  return *this;
+}
+
+inline bool Object::iterator::operator==(const iterator& other) const {
+  return _index == other._index;
+}
+
+inline bool Object::iterator::operator!=(const iterator& other) const {
+  return _index != other._index;
+}
+
+inline std::pair<Value, Object::PropertyLValue<Value>>
+Object::iterator::operator*() {
+  Value key = _keys[_index];
+  PropertyLValue<Value> value = (*_object)[key];
+  return {key, value};
+}
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+
+#if NAPI_VERSION >= 8
+inline MaybeOrValue<bool> Object::Freeze() const {
+  napi_status status = napi_object_freeze(_env, _value);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::Seal() const {
+  napi_status status = napi_object_seal(_env, _value);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+#endif  // NAPI_VERSION >= 8
+
+////////////////////////////////////////////////////////////////////////////////
+// External class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline External<T> External<T>::New(napi_env env, T* data) {
+  napi_value value;
+  napi_status status =
+      napi_create_external(env, data, nullptr, nullptr, &value);
+  NAPI_THROW_IF_FAILED(env, status, External());
+  return External(env, value);
+}
+
+template <typename T>
+template <typename Finalizer>
+inline External<T> External<T>::New(napi_env env,
+                                    T* data,
+                                    Finalizer finalizeCallback) {
+  napi_value value;
+  details::FinalizeData<T, Finalizer>* finalizeData =
+      new details::FinalizeData<T, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+  napi_status status =
+      napi_create_external(env,
+                           data,
+                           details::FinalizeData<T, Finalizer>::Wrapper,
+                           finalizeData,
+                           &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, External());
+  }
+  return External(env, value);
+}
+
+template <typename T>
+template <typename Finalizer, typename Hint>
+inline External<T> External<T>::New(napi_env env,
+                                    T* data,
+                                    Finalizer finalizeCallback,
+                                    Hint* finalizeHint) {
+  napi_value value;
+  details::FinalizeData<T, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<T, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+  napi_status status = napi_create_external(
+      env,
+      data,
+      details::FinalizeData<T, Finalizer, Hint>::WrapperWithHint,
+      finalizeData,
+      &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, External());
+  }
+  return External(env, value);
+}
+
+template <typename T>
+inline void External<T>::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "External::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "External::CheckCast", "napi_typeof failed");
+  NAPI_INTERNAL_CHECK_EQ(type, napi_external, "%d", "External::CheckCast");
+}
+
+template <typename T>
+inline External<T>::External() : TypeTaggable() {}
+
+template <typename T>
+inline External<T>::External(napi_env env, napi_value value)
+    : TypeTaggable(env, value) {}
+
+template <typename T>
+inline T* External<T>::Data() const {
+  void* data;
+  napi_status status = napi_get_value_external(_env, _value, &data);
+  NAPI_THROW_IF_FAILED(_env, status, nullptr);
+  return reinterpret_cast<T*>(data);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Array class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Array Array::New(napi_env env) {
+  napi_value value;
+  napi_status status = napi_create_array(env, &value);
+  NAPI_THROW_IF_FAILED(env, status, Array());
+  return Array(env, value);
+}
+
+inline Array Array::New(napi_env env, size_t length) {
+  napi_value value;
+  napi_status status = napi_create_array_with_length(env, length, &value);
+  NAPI_THROW_IF_FAILED(env, status, Array());
+  return Array(env, value);
+}
+
+inline void Array::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Array::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_array(env, value, &result);
+  NAPI_CHECK(status == napi_ok, "Array::CheckCast", "napi_is_array failed");
+  NAPI_CHECK(result, "Array::CheckCast", "value is not array");
+}
+
+inline Array::Array() : Object() {}
+
+inline Array::Array(napi_env env, napi_value value) : Object(env, value) {}
+
+inline uint32_t Array::Length() const {
+  uint32_t result;
+  napi_status status = napi_get_array_length(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ArrayBuffer class
+////////////////////////////////////////////////////////////////////////////////
+
+inline ArrayBuffer ArrayBuffer::New(napi_env env, size_t byteLength) {
+  napi_value value;
+  void* data;
+  napi_status status = napi_create_arraybuffer(env, byteLength, &data, &value);
+  NAPI_THROW_IF_FAILED(env, status, ArrayBuffer());
+
+  return ArrayBuffer(env, value);
+}
+
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+inline ArrayBuffer ArrayBuffer::New(napi_env env,
+                                    void* externalData,
+                                    size_t byteLength) {
+  napi_value value;
+  napi_status status = napi_create_external_arraybuffer(
+      env, externalData, byteLength, nullptr, nullptr, &value);
+  NAPI_THROW_IF_FAILED(env, status, ArrayBuffer());
+
+  return ArrayBuffer(env, value);
+}
+
+template <typename Finalizer>
+inline ArrayBuffer ArrayBuffer::New(napi_env env,
+                                    void* externalData,
+                                    size_t byteLength,
+                                    Finalizer finalizeCallback) {
+  napi_value value;
+  details::FinalizeData<void, Finalizer>* finalizeData =
+      new details::FinalizeData<void, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+  napi_status status = napi_create_external_arraybuffer(
+      env,
+      externalData,
+      byteLength,
+      details::FinalizeData<void, Finalizer>::Wrapper,
+      finalizeData,
+      &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, ArrayBuffer());
+  }
+
+  return ArrayBuffer(env, value);
+}
+
+template <typename Finalizer, typename Hint>
+inline ArrayBuffer ArrayBuffer::New(napi_env env,
+                                    void* externalData,
+                                    size_t byteLength,
+                                    Finalizer finalizeCallback,
+                                    Hint* finalizeHint) {
+  napi_value value;
+  details::FinalizeData<void, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<void, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+  napi_status status = napi_create_external_arraybuffer(
+      env,
+      externalData,
+      byteLength,
+      details::FinalizeData<void, Finalizer, Hint>::WrapperWithHint,
+      finalizeData,
+      &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, ArrayBuffer());
+  }
+
+  return ArrayBuffer(env, value);
+}
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+
+inline void ArrayBuffer::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "ArrayBuffer::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_arraybuffer(env, value, &result);
+  NAPI_CHECK(status == napi_ok,
+             "ArrayBuffer::CheckCast",
+             "napi_is_arraybuffer failed");
+  NAPI_CHECK(result, "ArrayBuffer::CheckCast", "value is not arraybuffer");
+}
+
+inline ArrayBuffer::ArrayBuffer() : Object() {}
+
+inline ArrayBuffer::ArrayBuffer(napi_env env, napi_value value)
+    : Object(env, value) {}
+
+inline void* ArrayBuffer::Data() {
+  void* data;
+  napi_status status = napi_get_arraybuffer_info(_env, _value, &data, nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, nullptr);
+  return data;
+}
+
+inline size_t ArrayBuffer::ByteLength() {
+  size_t length;
+  napi_status status =
+      napi_get_arraybuffer_info(_env, _value, nullptr, &length);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return length;
+}
+
+#if NAPI_VERSION >= 7
+inline bool ArrayBuffer::IsDetached() const {
+  bool detached;
+  napi_status status = napi_is_detached_arraybuffer(_env, _value, &detached);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return detached;
+}
+
+inline void ArrayBuffer::Detach() {
+  napi_status status = napi_detach_arraybuffer(_env, _value);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+#endif  // NAPI_VERSION >= 7
+
+////////////////////////////////////////////////////////////////////////////////
+// DataView class
+////////////////////////////////////////////////////////////////////////////////
+inline DataView DataView::New(napi_env env, Napi::ArrayBuffer arrayBuffer) {
+  return New(env, arrayBuffer, 0, arrayBuffer.ByteLength());
+}
+
+inline DataView DataView::New(napi_env env,
+                              Napi::ArrayBuffer arrayBuffer,
+                              size_t byteOffset) {
+  if (byteOffset > arrayBuffer.ByteLength()) {
+    NAPI_THROW(RangeError::New(
+                   env, "Start offset is outside the bounds of the buffer"),
+               DataView());
+  }
+  return New(
+      env, arrayBuffer, byteOffset, arrayBuffer.ByteLength() - byteOffset);
+}
+
+inline DataView DataView::New(napi_env env,
+                              Napi::ArrayBuffer arrayBuffer,
+                              size_t byteOffset,
+                              size_t byteLength) {
+  if (byteOffset + byteLength > arrayBuffer.ByteLength()) {
+    NAPI_THROW(RangeError::New(env, "Invalid DataView length"), DataView());
+  }
+  napi_value value;
+  napi_status status =
+      napi_create_dataview(env, byteLength, arrayBuffer, byteOffset, &value);
+  NAPI_THROW_IF_FAILED(env, status, DataView());
+  return DataView(env, value);
+}
+
+inline void DataView::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "DataView::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_dataview(env, value, &result);
+  NAPI_CHECK(
+      status == napi_ok, "DataView::CheckCast", "napi_is_dataview failed");
+  NAPI_CHECK(result, "DataView::CheckCast", "value is not dataview");
+}
+
+inline DataView::DataView() : Object() {}
+
+inline DataView::DataView(napi_env env, napi_value value) : Object(env, value) {
+  napi_status status = napi_get_dataview_info(_env,
+                                              _value /* dataView */,
+                                              &_length /* byteLength */,
+                                              &_data /* data */,
+                                              nullptr /* arrayBuffer */,
+                                              nullptr /* byteOffset */);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline Napi::ArrayBuffer DataView::ArrayBuffer() const {
+  napi_value arrayBuffer;
+  napi_status status = napi_get_dataview_info(_env,
+                                              _value /* dataView */,
+                                              nullptr /* byteLength */,
+                                              nullptr /* data */,
+                                              &arrayBuffer /* arrayBuffer */,
+                                              nullptr /* byteOffset */);
+  NAPI_THROW_IF_FAILED(_env, status, Napi::ArrayBuffer());
+  return Napi::ArrayBuffer(_env, arrayBuffer);
+}
+
+inline size_t DataView::ByteOffset() const {
+  size_t byteOffset;
+  napi_status status = napi_get_dataview_info(_env,
+                                              _value /* dataView */,
+                                              nullptr /* byteLength */,
+                                              nullptr /* data */,
+                                              nullptr /* arrayBuffer */,
+                                              &byteOffset /* byteOffset */);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return byteOffset;
+}
+
+inline size_t DataView::ByteLength() const {
+  return _length;
+}
+
+inline void* DataView::Data() const {
+  return _data;
+}
+
+inline float DataView::GetFloat32(size_t byteOffset) const {
+  return ReadData<float>(byteOffset);
+}
+
+inline double DataView::GetFloat64(size_t byteOffset) const {
+  return ReadData<double>(byteOffset);
+}
+
+inline int8_t DataView::GetInt8(size_t byteOffset) const {
+  return ReadData<int8_t>(byteOffset);
+}
+
+inline int16_t DataView::GetInt16(size_t byteOffset) const {
+  return ReadData<int16_t>(byteOffset);
+}
+
+inline int32_t DataView::GetInt32(size_t byteOffset) const {
+  return ReadData<int32_t>(byteOffset);
+}
+
+inline uint8_t DataView::GetUint8(size_t byteOffset) const {
+  return ReadData<uint8_t>(byteOffset);
+}
+
+inline uint16_t DataView::GetUint16(size_t byteOffset) const {
+  return ReadData<uint16_t>(byteOffset);
+}
+
+inline uint32_t DataView::GetUint32(size_t byteOffset) const {
+  return ReadData<uint32_t>(byteOffset);
+}
+
+inline void DataView::SetFloat32(size_t byteOffset, float value) const {
+  WriteData<float>(byteOffset, value);
+}
+
+inline void DataView::SetFloat64(size_t byteOffset, double value) const {
+  WriteData<double>(byteOffset, value);
+}
+
+inline void DataView::SetInt8(size_t byteOffset, int8_t value) const {
+  WriteData<int8_t>(byteOffset, value);
+}
+
+inline void DataView::SetInt16(size_t byteOffset, int16_t value) const {
+  WriteData<int16_t>(byteOffset, value);
+}
+
+inline void DataView::SetInt32(size_t byteOffset, int32_t value) const {
+  WriteData<int32_t>(byteOffset, value);
+}
+
+inline void DataView::SetUint8(size_t byteOffset, uint8_t value) const {
+  WriteData<uint8_t>(byteOffset, value);
+}
+
+inline void DataView::SetUint16(size_t byteOffset, uint16_t value) const {
+  WriteData<uint16_t>(byteOffset, value);
+}
+
+inline void DataView::SetUint32(size_t byteOffset, uint32_t value) const {
+  WriteData<uint32_t>(byteOffset, value);
+}
+
+template <typename T>
+inline T DataView::ReadData(size_t byteOffset) const {
+  if (byteOffset + sizeof(T) > _length ||
+      byteOffset + sizeof(T) < byteOffset) {  // overflow
+    NAPI_THROW(
+        RangeError::New(_env, "Offset is outside the bounds of the DataView"),
+        0);
+  }
+
+  return *reinterpret_cast<T*>(static_cast<uint8_t*>(_data) + byteOffset);
+}
+
+template <typename T>
+inline void DataView::WriteData(size_t byteOffset, T value) const {
+  if (byteOffset + sizeof(T) > _length ||
+      byteOffset + sizeof(T) < byteOffset) {  // overflow
+    NAPI_THROW_VOID(
+        RangeError::New(_env, "Offset is outside the bounds of the DataView"));
+  }
+
+  *reinterpret_cast<T*>(static_cast<uint8_t*>(_data) + byteOffset) = value;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TypedArray class
+////////////////////////////////////////////////////////////////////////////////
+inline void TypedArray::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "TypedArray::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_typedarray(env, value, &result);
+  NAPI_CHECK(
+      status == napi_ok, "TypedArray::CheckCast", "napi_is_typedarray failed");
+  NAPI_CHECK(result, "TypedArray::CheckCast", "value is not typedarray");
+}
+
+inline TypedArray::TypedArray()
+    : Object(), _type(napi_typedarray_type::napi_int8_array), _length(0) {}
+
+inline TypedArray::TypedArray(napi_env env, napi_value value)
+    : Object(env, value),
+      _type(napi_typedarray_type::napi_int8_array),
+      _length(0) {
+  if (value != nullptr) {
+    napi_status status =
+        napi_get_typedarray_info(_env,
+                                 _value,
+                                 &const_cast<TypedArray*>(this)->_type,
+                                 &const_cast<TypedArray*>(this)->_length,
+                                 nullptr,
+                                 nullptr,
+                                 nullptr);
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+inline TypedArray::TypedArray(napi_env env,
+                              napi_value value,
+                              napi_typedarray_type type,
+                              size_t length)
+    : Object(env, value), _type(type), _length(length) {}
+
+inline napi_typedarray_type TypedArray::TypedArrayType() const {
+  return _type;
+}
+
+inline uint8_t TypedArray::ElementSize() const {
+  switch (_type) {
+    case napi_int8_array:
+    case napi_uint8_array:
+    case napi_uint8_clamped_array:
+      return 1;
+    case napi_int16_array:
+    case napi_uint16_array:
+      return 2;
+    case napi_int32_array:
+    case napi_uint32_array:
+    case napi_float32_array:
+      return 4;
+    case napi_float64_array:
+#if (NAPI_VERSION > 5)
+    case napi_bigint64_array:
+    case napi_biguint64_array:
+#endif  // (NAPI_VERSION > 5)
+      return 8;
+    default:
+      return 0;
+  }
+}
+
+inline size_t TypedArray::ElementLength() const {
+  return _length;
+}
+
+inline size_t TypedArray::ByteOffset() const {
+  size_t byteOffset;
+  napi_status status = napi_get_typedarray_info(
+      _env, _value, nullptr, nullptr, nullptr, nullptr, &byteOffset);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return byteOffset;
+}
+
+inline size_t TypedArray::ByteLength() const {
+  return ElementSize() * ElementLength();
+}
+
+inline Napi::ArrayBuffer TypedArray::ArrayBuffer() const {
+  napi_value arrayBuffer;
+  napi_status status = napi_get_typedarray_info(
+      _env, _value, nullptr, nullptr, nullptr, &arrayBuffer, nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, Napi::ArrayBuffer());
+  return Napi::ArrayBuffer(_env, arrayBuffer);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TypedArrayOf<T> class
+////////////////////////////////////////////////////////////////////////////////
+template <typename T>
+inline void TypedArrayOf<T>::CheckCast(napi_env env, napi_value value) {
+  TypedArray::CheckCast(env, value);
+  napi_typedarray_type type;
+  napi_status status = napi_get_typedarray_info(
+      env, value, &type, nullptr, nullptr, nullptr, nullptr);
+  NAPI_CHECK(status == napi_ok,
+             "TypedArrayOf::CheckCast",
+             "napi_is_typedarray failed");
+
+  NAPI_INTERNAL_CHECK(
+      (type == TypedArrayTypeForPrimitiveType<T>() ||
+       (type == napi_uint8_clamped_array && std::is_same<T, uint8_t>::value)),
+      "TypedArrayOf::CheckCast",
+      "Array type must match the template parameter, (Uint8 arrays may "
+      "optionally have the \"clamped\" array type.), got %d.",
+      type);
+}
+
+template <typename T>
+inline TypedArrayOf<T> TypedArrayOf<T>::New(napi_env env,
+                                            size_t elementLength,
+                                            napi_typedarray_type type) {
+  Napi::ArrayBuffer arrayBuffer =
+      Napi::ArrayBuffer::New(env, elementLength * sizeof(T));
+  return New(env, elementLength, arrayBuffer, 0, type);
+}
+
+template <typename T>
+inline TypedArrayOf<T> TypedArrayOf<T>::New(napi_env env,
+                                            size_t elementLength,
+                                            Napi::ArrayBuffer arrayBuffer,
+                                            size_t bufferOffset,
+                                            napi_typedarray_type type) {
+  napi_value value;
+  napi_status status = napi_create_typedarray(
+      env, type, elementLength, arrayBuffer, bufferOffset, &value);
+  NAPI_THROW_IF_FAILED(env, status, TypedArrayOf<T>());
+
+  return TypedArrayOf<T>(
+      env,
+      value,
+      type,
+      elementLength,
+      reinterpret_cast<T*>(reinterpret_cast<uint8_t*>(arrayBuffer.Data()) +
+                           bufferOffset));
+}
+
+template <typename T>
+inline TypedArrayOf<T>::TypedArrayOf() : TypedArray(), _data(nullptr) {}
+
+template <typename T>
+inline TypedArrayOf<T>::TypedArrayOf(napi_env env, napi_value value)
+    : TypedArray(env, value), _data(nullptr) {
+  napi_status status = napi_ok;
+  if (value != nullptr) {
+    void* data = nullptr;
+    status = napi_get_typedarray_info(
+        _env, _value, &_type, &_length, &data, nullptr, nullptr);
+    _data = static_cast<T*>(data);
+  } else {
+    _type = TypedArrayTypeForPrimitiveType<T>();
+    _length = 0;
+  }
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+template <typename T>
+inline TypedArrayOf<T>::TypedArrayOf(napi_env env,
+                                     napi_value value,
+                                     napi_typedarray_type type,
+                                     size_t length,
+                                     T* data)
+    : TypedArray(env, value, type, length), _data(data) {
+  if (!(type == TypedArrayTypeForPrimitiveType<T>() ||
+        (type == napi_uint8_clamped_array &&
+         std::is_same<T, uint8_t>::value))) {
+    NAPI_THROW_VOID(TypeError::New(
+        env,
+        "Array type must match the template parameter. "
+        "(Uint8 arrays may optionally have the \"clamped\" array type.)"));
+  }
+}
+
+template <typename T>
+inline T& TypedArrayOf<T>::operator[](size_t index) {
+  return _data[index];
+}
+
+template <typename T>
+inline const T& TypedArrayOf<T>::operator[](size_t index) const {
+  return _data[index];
+}
+
+template <typename T>
+inline T* TypedArrayOf<T>::Data() {
+  return _data;
+}
+
+template <typename T>
+inline const T* TypedArrayOf<T>::Data() const {
+  return _data;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Function class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename CbData>
+inline napi_status CreateFunction(napi_env env,
+                                  const char* utf8name,
+                                  napi_callback cb,
+                                  CbData* data,
+                                  napi_value* result) {
+  napi_status status =
+      napi_create_function(env, utf8name, NAPI_AUTO_LENGTH, cb, data, result);
+  if (status == napi_ok) {
+    status = Napi::details::AttachData(env, *result, data);
+  }
+
+  return status;
+}
+
+template <Function::VoidCallback cb>
+inline Function Function::New(napi_env env, const char* utf8name, void* data) {
+  napi_value result = nullptr;
+  napi_status status = napi_create_function(env,
+                                            utf8name,
+                                            NAPI_AUTO_LENGTH,
+                                            details::TemplatedVoidCallback<cb>,
+                                            data,
+                                            &result);
+  NAPI_THROW_IF_FAILED(env, status, Function());
+  return Function(env, result);
+}
+
+template <Function::Callback cb>
+inline Function Function::New(napi_env env, const char* utf8name, void* data) {
+  napi_value result = nullptr;
+  napi_status status = napi_create_function(env,
+                                            utf8name,
+                                            NAPI_AUTO_LENGTH,
+                                            details::TemplatedCallback<cb>,
+                                            data,
+                                            &result);
+  NAPI_THROW_IF_FAILED(env, status, Function());
+  return Function(env, result);
+}
+
+template <Function::VoidCallback cb>
+inline Function Function::New(napi_env env,
+                              const std::string& utf8name,
+                              void* data) {
+  return Function::New<cb>(env, utf8name.c_str(), data);
+}
+
+template <Function::Callback cb>
+inline Function Function::New(napi_env env,
+                              const std::string& utf8name,
+                              void* data) {
+  return Function::New<cb>(env, utf8name.c_str(), data);
+}
+
+template <typename Callable>
+inline Function Function::New(napi_env env,
+                              Callable cb,
+                              const char* utf8name,
+                              void* data) {
+  using ReturnType = decltype(cb(CallbackInfo(nullptr, nullptr)));
+  using CbData = details::CallbackData<Callable, ReturnType>;
+  auto callbackData = new CbData{std::move(cb), data};
+
+  napi_value value;
+  napi_status status =
+      CreateFunction(env, utf8name, CbData::Wrapper, callbackData, &value);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, Function());
+  }
+
+  return Function(env, value);
+}
+
+template <typename Callable>
+inline Function Function::New(napi_env env,
+                              Callable cb,
+                              const std::string& utf8name,
+                              void* data) {
+  return New(env, cb, utf8name.c_str(), data);
+}
+
+inline void Function::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Function::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Function::CheckCast", "napi_typeof failed");
+  NAPI_INTERNAL_CHECK_EQ(type, napi_function, "%d", "Function::CheckCast");
+}
+
+inline Function::Function() : Object() {}
+
+inline Function::Function(napi_env env, napi_value value)
+    : Object(env, value) {}
+
+inline MaybeOrValue<Value> Function::operator()(
+    const std::initializer_list<napi_value>& args) const {
+  return Call(Env().Undefined(), args);
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    const std::initializer_list<napi_value>& args) const {
+  return Call(Env().Undefined(), args);
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    const std::vector<napi_value>& args) const {
+  return Call(Env().Undefined(), args);
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    const std::vector<Value>& args) const {
+  return Call(Env().Undefined(), args);
+}
+
+inline MaybeOrValue<Value> Function::Call(size_t argc,
+                                          const napi_value* args) const {
+  return Call(Env().Undefined(), argc, args);
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    napi_value recv, const std::initializer_list<napi_value>& args) const {
+  return Call(recv, args.size(), args.begin());
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    napi_value recv, const std::vector<napi_value>& args) const {
+  return Call(recv, args.size(), args.data());
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    napi_value recv, const std::vector<Value>& args) const {
+  const size_t argc = args.size();
+  const size_t stackArgsCount = 6;
+  napi_value stackArgs[stackArgsCount];
+  std::vector<napi_value> heapArgs;
+  napi_value* argv;
+  if (argc <= stackArgsCount) {
+    argv = stackArgs;
+  } else {
+    heapArgs.resize(argc);
+    argv = heapArgs.data();
+  }
+
+  for (size_t index = 0; index < argc; index++) {
+    argv[index] = static_cast<napi_value>(args[index]);
+  }
+
+  return Call(recv, argc, argv);
+}
+
+inline MaybeOrValue<Value> Function::Call(napi_value recv,
+                                          size_t argc,
+                                          const napi_value* args) const {
+  napi_value result;
+  napi_status status =
+      napi_call_function(_env, recv, _value, argc, args, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Value(_env, result), Napi::Value);
+}
+
+inline MaybeOrValue<Value> Function::MakeCallback(
+    napi_value recv,
+    const std::initializer_list<napi_value>& args,
+    napi_async_context context) const {
+  return MakeCallback(recv, args.size(), args.begin(), context);
+}
+
+inline MaybeOrValue<Value> Function::MakeCallback(
+    napi_value recv,
+    const std::vector<napi_value>& args,
+    napi_async_context context) const {
+  return MakeCallback(recv, args.size(), args.data(), context);
+}
+
+inline MaybeOrValue<Value> Function::MakeCallback(
+    napi_value recv,
+    size_t argc,
+    const napi_value* args,
+    napi_async_context context) const {
+  napi_value result;
+  napi_status status =
+      napi_make_callback(_env, context, recv, _value, argc, args, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Value(_env, result), Napi::Value);
+}
+
+inline MaybeOrValue<Object> Function::New(
+    const std::initializer_list<napi_value>& args) const {
+  return New(args.size(), args.begin());
+}
+
+inline MaybeOrValue<Object> Function::New(
+    const std::vector<napi_value>& args) const {
+  return New(args.size(), args.data());
+}
+
+inline MaybeOrValue<Object> Function::New(size_t argc,
+                                          const napi_value* args) const {
+  napi_value result;
+  napi_status status = napi_new_instance(_env, _value, argc, args, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Object(_env, result), Napi::Object);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Promise class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Promise::Deferred Promise::Deferred::New(napi_env env) {
+  return Promise::Deferred(env);
+}
+
+inline Promise::Deferred::Deferred(napi_env env) : _env(env) {
+  napi_status status = napi_create_promise(_env, &_deferred, &_promise);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline Promise Promise::Deferred::Promise() const {
+  return Napi::Promise(_env, _promise);
+}
+
+inline Napi::Env Promise::Deferred::Env() const {
+  return Napi::Env(_env);
+}
+
+inline void Promise::Deferred::Resolve(napi_value value) const {
+  napi_status status = napi_resolve_deferred(_env, _deferred, value);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline void Promise::Deferred::Reject(napi_value value) const {
+  napi_status status = napi_reject_deferred(_env, _deferred, value);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline void Promise::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Promise::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_promise(env, value, &result);
+  NAPI_CHECK(status == napi_ok, "Promise::CheckCast", "napi_is_promise failed");
+  NAPI_CHECK(result, "Promise::CheckCast", "value is not promise");
+}
+
+inline Promise::Promise() : Object() {}
+
+inline Promise::Promise(napi_env env, napi_value value) : Object(env, value) {}
+
+inline MaybeOrValue<Promise> Promise::Then(napi_value onFulfilled) const {
+  EscapableHandleScope scope(_env);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  Value thenMethod;
+  if (!Get("then").UnwrapTo(&thenMethod)) {
+    return Nothing<Promise>();
+  }
+  MaybeOrValue<Value> result =
+      thenMethod.As<Function>().Call(*this, {onFulfilled});
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()).As<Promise>());
+  }
+  return Nothing<Promise>();
+#else
+  Function thenMethod = Get("then").As<Function>();
+  MaybeOrValue<Value> result = thenMethod.Call(*this, {onFulfilled});
+  if (scope.Env().IsExceptionPending()) {
+    return Promise();
+  }
+  return scope.Escape(result).As<Promise>();
+#endif
+}
+
+inline MaybeOrValue<Promise> Promise::Then(napi_value onFulfilled,
+                                           napi_value onRejected) const {
+  EscapableHandleScope scope(_env);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  Value thenMethod;
+  if (!Get("then").UnwrapTo(&thenMethod)) {
+    return Nothing<Promise>();
+  }
+  MaybeOrValue<Value> result =
+      thenMethod.As<Function>().Call(*this, {onFulfilled, onRejected});
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()).As<Promise>());
+  }
+  return Nothing<Promise>();
+#else
+  Function thenMethod = Get("then").As<Function>();
+  MaybeOrValue<Value> result =
+      thenMethod.Call(*this, {onFulfilled, onRejected});
+  if (scope.Env().IsExceptionPending()) {
+    return Promise();
+  }
+  return scope.Escape(result).As<Promise>();
+#endif
+}
+
+inline MaybeOrValue<Promise> Promise::Catch(napi_value onRejected) const {
+  EscapableHandleScope scope(_env);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  Value catchMethod;
+  if (!Get("catch").UnwrapTo(&catchMethod)) {
+    return Nothing<Promise>();
+  }
+  MaybeOrValue<Value> result =
+      catchMethod.As<Function>().Call(*this, {onRejected});
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()).As<Promise>());
+  }
+  return Nothing<Promise>();
+#else
+  Function catchMethod = Get("catch").As<Function>();
+  MaybeOrValue<Value> result = catchMethod.Call(*this, {onRejected});
+  if (scope.Env().IsExceptionPending()) {
+    return Promise();
+  }
+  return scope.Escape(result).As<Promise>();
+#endif
+}
+
+inline MaybeOrValue<Promise> Promise::Then(const Function& onFulfilled) const {
+  return Then(static_cast<napi_value>(onFulfilled));
+}
+
+inline MaybeOrValue<Promise> Promise::Then(const Function& onFulfilled,
+                                           const Function& onRejected) const {
+  return Then(static_cast<napi_value>(onFulfilled),
+              static_cast<napi_value>(onRejected));
+}
+
+inline MaybeOrValue<Promise> Promise::Catch(const Function& onRejected) const {
+  return Catch(static_cast<napi_value>(onRejected));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Buffer<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline Buffer<T> Buffer<T>::New(napi_env env, size_t length) {
+  napi_value value;
+  void* data;
+  napi_status status =
+      napi_create_buffer(env, length * sizeof(T), &data, &value);
+  NAPI_THROW_IF_FAILED(env, status, Buffer<T>());
+  return Buffer(env, value);
+}
+
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+template <typename T>
+inline Buffer<T> Buffer<T>::New(napi_env env, T* data, size_t length) {
+  napi_value value;
+  napi_status status = napi_create_external_buffer(
+      env, length * sizeof(T), data, nullptr, nullptr, &value);
+  NAPI_THROW_IF_FAILED(env, status, Buffer<T>());
+  return Buffer(env, value);
+}
+
+template <typename T>
+template <typename Finalizer>
+inline Buffer<T> Buffer<T>::New(napi_env env,
+                                T* data,
+                                size_t length,
+                                Finalizer finalizeCallback) {
+  napi_value value;
+  details::FinalizeData<T, Finalizer>* finalizeData =
+      new details::FinalizeData<T, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+  napi_status status =
+      napi_create_external_buffer(env,
+                                  length * sizeof(T),
+                                  data,
+                                  details::FinalizeData<T, Finalizer>::Wrapper,
+                                  finalizeData,
+                                  &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, Buffer());
+  }
+  return Buffer(env, value);
+}
+
+template <typename T>
+template <typename Finalizer, typename Hint>
+inline Buffer<T> Buffer<T>::New(napi_env env,
+                                T* data,
+                                size_t length,
+                                Finalizer finalizeCallback,
+                                Hint* finalizeHint) {
+  napi_value value;
+  details::FinalizeData<T, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<T, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+  napi_status status = napi_create_external_buffer(
+      env,
+      length * sizeof(T),
+      data,
+      details::FinalizeData<T, Finalizer, Hint>::WrapperWithHint,
+      finalizeData,
+      &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, Buffer());
+  }
+  return Buffer(env, value);
+}
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+
+template <typename T>
+inline Buffer<T> Buffer<T>::NewOrCopy(napi_env env, T* data, size_t length) {
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  napi_value value;
+  napi_status status = napi_create_external_buffer(
+      env, length * sizeof(T), data, nullptr, nullptr, &value);
+  if (status == details::napi_no_external_buffers_allowed) {
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+    // If we can't create an external buffer, we'll just copy the data.
+    return Buffer<T>::Copy(env, data, length);
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  }
+  NAPI_THROW_IF_FAILED(env, status, Buffer<T>());
+  return Buffer(env, value);
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+}
+
+template <typename T>
+template <typename Finalizer>
+inline Buffer<T> Buffer<T>::NewOrCopy(napi_env env,
+                                      T* data,
+                                      size_t length,
+                                      Finalizer finalizeCallback) {
+  details::FinalizeData<T, Finalizer>* finalizeData =
+      new details::FinalizeData<T, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  napi_value value;
+  napi_status status =
+      napi_create_external_buffer(env,
+                                  length * sizeof(T),
+                                  data,
+                                  details::FinalizeData<T, Finalizer>::Wrapper,
+                                  finalizeData,
+                                  &value);
+  if (status == details::napi_no_external_buffers_allowed) {
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+    // If we can't create an external buffer, we'll just copy the data.
+    Buffer<T> ret = Buffer<T>::Copy(env, data, length);
+    details::FinalizeData<T, Finalizer>::WrapperGC(env, data, finalizeData);
+    return ret;
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  }
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, Buffer());
+  }
+  return Buffer(env, value);
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+}
+
+template <typename T>
+template <typename Finalizer, typename Hint>
+inline Buffer<T> Buffer<T>::NewOrCopy(napi_env env,
+                                      T* data,
+                                      size_t length,
+                                      Finalizer finalizeCallback,
+                                      Hint* finalizeHint) {
+  details::FinalizeData<T, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<T, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  napi_value value;
+  napi_status status = napi_create_external_buffer(
+      env,
+      length * sizeof(T),
+      data,
+      details::FinalizeData<T, Finalizer, Hint>::WrapperWithHint,
+      finalizeData,
+      &value);
+  if (status == details::napi_no_external_buffers_allowed) {
+#endif
+    // If we can't create an external buffer, we'll just copy the data.
+    Buffer<T> ret = Buffer<T>::Copy(env, data, length);
+    details::FinalizeData<T, Finalizer, Hint>::WrapperGCWithHint(
+        env, data, finalizeData);
+    return ret;
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  }
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, Buffer());
+  }
+  return Buffer(env, value);
+#endif
+}
+
+template <typename T>
+inline Buffer<T> Buffer<T>::Copy(napi_env env, const T* data, size_t length) {
+  napi_value value;
+  napi_status status =
+      napi_create_buffer_copy(env, length * sizeof(T), data, nullptr, &value);
+  NAPI_THROW_IF_FAILED(env, status, Buffer<T>());
+  return Buffer<T>(env, value);
+}
+
+template <typename T>
+inline void Buffer<T>::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Buffer::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_buffer(env, value, &result);
+  NAPI_CHECK(status == napi_ok, "Buffer::CheckCast", "napi_is_buffer failed");
+  NAPI_CHECK(result, "Buffer::CheckCast", "value is not buffer");
+}
+
+template <typename T>
+inline Buffer<T>::Buffer() : Uint8Array() {}
+
+template <typename T>
+inline Buffer<T>::Buffer(napi_env env, napi_value value)
+    : Uint8Array(env, value) {}
+
+template <typename T>
+inline size_t Buffer<T>::Length() const {
+  return ByteLength() / sizeof(T);
+}
+
+template <typename T>
+inline T* Buffer<T>::Data() const {
+  return reinterpret_cast<T*>(const_cast<uint8_t*>(Uint8Array::Data()));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Error class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Error Error::New(napi_env env) {
+  napi_status status;
+  napi_value error = nullptr;
+  bool is_exception_pending;
+  napi_extended_error_info last_error_info_copy;
+
+  {
+    // We must retrieve the last error info before doing anything else because
+    // doing anything else will replace the last error info.
+    const napi_extended_error_info* last_error_info;
+    status = napi_get_last_error_info(env, &last_error_info);
+    NAPI_FATAL_IF_FAILED(status, "Error::New", "napi_get_last_error_info");
+
+    // All fields of the `napi_extended_error_info` structure gets reset in
+    // subsequent Node-API function calls on the same `env`. This includes a
+    // call to `napi_is_exception_pending()`. So here it is necessary to make a
+    // copy of the information as the `error_code` field is used later on.
+    memcpy(&last_error_info_copy,
+           last_error_info,
+           sizeof(napi_extended_error_info));
+  }
+
+  status = napi_is_exception_pending(env, &is_exception_pending);
+  NAPI_FATAL_IF_FAILED(status, "Error::New", "napi_is_exception_pending");
+
+  // A pending exception takes precedence over any internal error status.
+  if (is_exception_pending) {
+    status = napi_get_and_clear_last_exception(env, &error);
+    NAPI_FATAL_IF_FAILED(
+        status, "Error::New", "napi_get_and_clear_last_exception");
+  } else {
+    const char* error_message = last_error_info_copy.error_message != nullptr
+                                    ? last_error_info_copy.error_message
+                                    : "Error in native callback";
+
+    napi_value message;
+    status = napi_create_string_utf8(
+        env, error_message, std::strlen(error_message), &message);
+    NAPI_FATAL_IF_FAILED(status, "Error::New", "napi_create_string_utf8");
+
+    switch (last_error_info_copy.error_code) {
+      case napi_object_expected:
+      case napi_string_expected:
+      case napi_boolean_expected:
+      case napi_number_expected:
+        status = napi_create_type_error(env, nullptr, message, &error);
+        break;
+      default:
+        status = napi_create_error(env, nullptr, message, &error);
+        break;
+    }
+    NAPI_FATAL_IF_FAILED(status, "Error::New", "napi_create_error");
+  }
+
+  return Error(env, error);
+}
+
+inline Error Error::New(napi_env env, const char* message) {
+  return Error::New<Error>(
+      env, message, std::strlen(message), napi_create_error);
+}
+
+inline Error Error::New(napi_env env, const std::string& message) {
+  return Error::New<Error>(
+      env, message.c_str(), message.size(), napi_create_error);
+}
+
+inline NAPI_NO_RETURN void Error::Fatal(const char* location,
+                                        const char* message) {
+  napi_fatal_error(location, NAPI_AUTO_LENGTH, message, NAPI_AUTO_LENGTH);
+}
+
+inline Error::Error() : ObjectReference() {}
+
+inline Error::Error(napi_env env, napi_value value)
+    : ObjectReference(env, nullptr) {
+  if (value != nullptr) {
+    // Attempting to create a reference on the error object.
+    // If it's not a Object/Function/Symbol, this call will return an error
+    // status.
+    napi_status status = napi_create_reference(env, value, 1, &_ref);
+
+    if (status != napi_ok) {
+      napi_value wrappedErrorObj;
+
+      // Create an error object
+      status = napi_create_object(env, &wrappedErrorObj);
+      NAPI_FATAL_IF_FAILED(status, "Error::Error", "napi_create_object");
+
+      // property flag that we attach to show the error object is wrapped
+      napi_property_descriptor wrapObjFlag = {
+          ERROR_WRAP_VALUE(),  // Unique GUID identifier since Symbol isn't a
+                               // viable option
+          nullptr,
+          nullptr,
+          nullptr,
+          nullptr,
+          Value::From(env, value),
+          napi_enumerable,
+          nullptr};
+
+      status = napi_define_properties(env, wrappedErrorObj, 1, &wrapObjFlag);
+#ifdef NODE_API_SWALLOW_UNTHROWABLE_EXCEPTIONS
+      if (status == napi_pending_exception) {
+        // Test if the pending exception was reported because the environment is
+        // shutting down. We assume that a status of napi_pending_exception
+        // coupled with the absence of an actual pending exception means that
+        // the environment is shutting down. If so, we replace the
+        // napi_pending_exception status with napi_ok.
+        bool is_exception_pending = false;
+        status = napi_is_exception_pending(env, &is_exception_pending);
+        if (status == napi_ok && !is_exception_pending) {
+          status = napi_ok;
+        } else {
+          status = napi_pending_exception;
+        }
+      }
+#endif  // NODE_API_SWALLOW_UNTHROWABLE_EXCEPTIONS
+      NAPI_FATAL_IF_FAILED(status, "Error::Error", "napi_define_properties");
+
+      // Create a reference on the newly wrapped object
+      status = napi_create_reference(env, wrappedErrorObj, 1, &_ref);
+    }
+
+    // Avoid infinite recursion in the failure case.
+    NAPI_FATAL_IF_FAILED(status, "Error::Error", "napi_create_reference");
+  }
+}
+
+inline Object Error::Value() const {
+  if (_ref == nullptr) {
+    return Object(_env, nullptr);
+  }
+
+  napi_value refValue;
+  napi_status status = napi_get_reference_value(_env, _ref, &refValue);
+  NAPI_THROW_IF_FAILED(_env, status, Object());
+
+  napi_valuetype type;
+  status = napi_typeof(_env, refValue, &type);
+  NAPI_THROW_IF_FAILED(_env, status, Object());
+
+  // If refValue isn't a symbol, then we proceed to whether the refValue has the
+  // wrapped error flag
+  if (type != napi_symbol) {
+    // We are checking if the object is wrapped
+    bool isWrappedObject = false;
+
+    status = napi_has_property(_env,
+                               refValue,
+                               String::From(_env, ERROR_WRAP_VALUE()),
+                               &isWrappedObject);
+
+    // Don't care about status
+    if (isWrappedObject) {
+      napi_value unwrappedValue;
+      status = napi_get_property(_env,
+                                 refValue,
+                                 String::From(_env, ERROR_WRAP_VALUE()),
+                                 &unwrappedValue);
+      NAPI_THROW_IF_FAILED(_env, status, Object());
+
+      return Object(_env, unwrappedValue);
+    }
+  }
+
+  return Object(_env, refValue);
+}
+
+inline Error::Error(Error&& other) : ObjectReference(std::move(other)) {}
+
+inline Error& Error::operator=(Error&& other) {
+  static_cast<Reference<Object>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline Error::Error(const Error& other) : ObjectReference(other) {}
+
+inline Error& Error::operator=(const Error& other) {
+  Reset();
+
+  _env = other.Env();
+  HandleScope scope(_env);
+
+  napi_value value = other.Value();
+  if (value != nullptr) {
+    napi_status status = napi_create_reference(_env, value, 1, &_ref);
+    NAPI_THROW_IF_FAILED(_env, status, *this);
+  }
+
+  return *this;
+}
+
+inline const std::string& Error::Message() const NAPI_NOEXCEPT {
+  if (_message.size() == 0 && _env != nullptr) {
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+    try {
+      _message = Get("message").As<String>();
+    } catch (...) {
+      // Catch all errors here, to include e.g. a std::bad_alloc from
+      // the std::string::operator=, because this method may not throw.
+    }
+#else  // NODE_ADDON_API_CPP_EXCEPTIONS
+#if defined(NODE_ADDON_API_ENABLE_MAYBE)
+    Napi::Value message_val;
+    if (Get("message").UnwrapTo(&message_val)) {
+      _message = message_val.As<String>();
+    }
+#else
+    _message = Get("message").As<String>();
+#endif
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+  }
+  return _message;
+}
+
+// we created an object on the &_ref
+inline void Error::ThrowAsJavaScriptException() const {
+  HandleScope scope(_env);
+  if (!IsEmpty()) {
+#ifdef NODE_API_SWALLOW_UNTHROWABLE_EXCEPTIONS
+    bool pendingException = false;
+
+    // check if there is already a pending exception. If so don't try to throw a
+    // new one as that is not allowed/possible
+    napi_status status = napi_is_exception_pending(_env, &pendingException);
+
+    if ((status != napi_ok) ||
+        ((status == napi_ok) && (pendingException == false))) {
+      // We intentionally don't use `NAPI_THROW_*` macros here to ensure
+      // that there is no possible recursion as `ThrowAsJavaScriptException`
+      // is part of `NAPI_THROW_*` macro definition for noexcept.
+
+      status = napi_throw(_env, Value());
+
+#if (NAPI_VERSION >= 10)
+      napi_status expected_failure_mode = napi_cannot_run_js;
+#else
+      napi_status expected_failure_mode = napi_pending_exception;
+#endif
+      if (status == expected_failure_mode) {
+        // The environment must be terminating as we checked earlier and there
+        // was no pending exception. In this case continuing will result
+        // in a fatal error and there is nothing the author has done incorrectly
+        // in their code that is worth flagging through a fatal error
+        return;
+      }
+    } else {
+      status = napi_pending_exception;
+    }
+#else
+    // We intentionally don't use `NAPI_THROW_*` macros here to ensure
+    // that there is no possible recursion as `ThrowAsJavaScriptException`
+    // is part of `NAPI_THROW_*` macro definition for noexcept.
+
+    napi_status status = napi_throw(_env, Value());
+#endif
+
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+    if (status != napi_ok) {
+      throw Error::New(_env);
+    }
+#else   // NODE_ADDON_API_CPP_EXCEPTIONS
+    NAPI_FATAL_IF_FAILED(
+        status, "Error::ThrowAsJavaScriptException", "napi_throw");
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+  }
+}
+
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+
+inline const char* Error::what() const NAPI_NOEXCEPT {
+  return Message().c_str();
+}
+
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+
+inline const char* Error::ERROR_WRAP_VALUE() NAPI_NOEXCEPT {
+  return "4bda9e7e-4913-4dbc-95de-891cbf66598e-errorVal";
+}
+
+template <typename TError>
+inline TError Error::New(napi_env env,
+                         const char* message,
+                         size_t length,
+                         create_error_fn create_error) {
+  napi_value str;
+  napi_status status = napi_create_string_utf8(env, message, length, &str);
+  NAPI_THROW_IF_FAILED(env, status, TError());
+
+  napi_value error;
+  status = create_error(env, nullptr, str, &error);
+  NAPI_THROW_IF_FAILED(env, status, TError());
+
+  return TError(env, error);
+}
+
+inline TypeError TypeError::New(napi_env env, const char* message) {
+  return Error::New<TypeError>(
+      env, message, std::strlen(message), napi_create_type_error);
+}
+
+inline TypeError TypeError::New(napi_env env, const std::string& message) {
+  return Error::New<TypeError>(
+      env, message.c_str(), message.size(), napi_create_type_error);
+}
+
+inline TypeError::TypeError() : Error() {}
+
+inline TypeError::TypeError(napi_env env, napi_value value)
+    : Error(env, value) {}
+
+inline RangeError RangeError::New(napi_env env, const char* message) {
+  return Error::New<RangeError>(
+      env, message, std::strlen(message), napi_create_range_error);
+}
+
+inline RangeError RangeError::New(napi_env env, const std::string& message) {
+  return Error::New<RangeError>(
+      env, message.c_str(), message.size(), napi_create_range_error);
+}
+
+inline RangeError::RangeError() : Error() {}
+
+inline RangeError::RangeError(napi_env env, napi_value value)
+    : Error(env, value) {}
+
+#if NAPI_VERSION > 8
+inline SyntaxError SyntaxError::New(napi_env env, const char* message) {
+  return Error::New<SyntaxError>(
+      env, message, std::strlen(message), node_api_create_syntax_error);
+}
+
+inline SyntaxError SyntaxError::New(napi_env env, const std::string& message) {
+  return Error::New<SyntaxError>(
+      env, message.c_str(), message.size(), node_api_create_syntax_error);
+}
+
+inline SyntaxError::SyntaxError() : Error() {}
+
+inline SyntaxError::SyntaxError(napi_env env, napi_value value)
+    : Error(env, value) {}
+#endif  // NAPI_VERSION > 8
+
+////////////////////////////////////////////////////////////////////////////////
+// Reference<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline Reference<T> Reference<T>::New(const T& value,
+                                      uint32_t initialRefcount) {
+  napi_env env = value.Env();
+  napi_value val = value;
+
+  if (val == nullptr) {
+    return Reference<T>(env, nullptr);
+  }
+
+  napi_ref ref;
+  napi_status status = napi_create_reference(env, value, initialRefcount, &ref);
+  NAPI_THROW_IF_FAILED(env, status, Reference<T>());
+
+  return Reference<T>(env, ref);
+}
+
+template <typename T>
+inline Reference<T>::Reference()
+    : _env(nullptr), _ref(nullptr), _suppressDestruct(false) {}
+
+template <typename T>
+inline Reference<T>::Reference(napi_env env, napi_ref ref)
+    : _env(env), _ref(ref), _suppressDestruct(false) {}
+
+template <typename T>
+inline Reference<T>::~Reference() {
+  if (_ref != nullptr) {
+    if (!_suppressDestruct) {
+      // TODO(legendecas): napi_delete_reference should be invoked immediately.
+      // Fix this when https://github.com/nodejs/node/pull/55620 lands.
+#ifdef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+      Env().PostFinalizer(
+          [](Napi::Env env, napi_ref ref) { napi_delete_reference(env, ref); },
+          _ref);
+#else
+      napi_delete_reference(_env, _ref);
+#endif
+    }
+
+    _ref = nullptr;
+  }
+}
+
+template <typename T>
+inline Reference<T>::Reference(Reference<T>&& other)
+    : _env(other._env),
+      _ref(other._ref),
+      _suppressDestruct(other._suppressDestruct) {
+  other._env = nullptr;
+  other._ref = nullptr;
+  other._suppressDestruct = false;
+}
+
+template <typename T>
+inline Reference<T>& Reference<T>::operator=(Reference<T>&& other) {
+  Reset();
+  _env = other._env;
+  _ref = other._ref;
+  _suppressDestruct = other._suppressDestruct;
+  other._env = nullptr;
+  other._ref = nullptr;
+  other._suppressDestruct = false;
+  return *this;
+}
+
+template <typename T>
+inline Reference<T>::Reference(const Reference<T>& other)
+    : _env(other._env), _ref(nullptr), _suppressDestruct(false) {
+  HandleScope scope(_env);
+
+  napi_value value = other.Value();
+  if (value != nullptr) {
+    // Copying is a limited scenario (currently only used for Error object) and
+    // always creates a strong reference to the given value even if the incoming
+    // reference is weak.
+    napi_status status = napi_create_reference(_env, value, 1, &_ref);
+    NAPI_FATAL_IF_FAILED(
+        status, "Reference<T>::Reference", "napi_create_reference");
+  }
+}
+
+template <typename T>
+inline Reference<T>::operator napi_ref() const {
+  return _ref;
+}
+
+template <typename T>
+inline bool Reference<T>::operator==(const Reference<T>& other) const {
+  HandleScope scope(_env);
+  return this->Value().StrictEquals(other.Value());
+}
+
+template <typename T>
+inline bool Reference<T>::operator!=(const Reference<T>& other) const {
+  return !this->operator==(other);
+}
+
+template <typename T>
+inline Napi::Env Reference<T>::Env() const {
+  return Napi::Env(_env);
+}
+
+template <typename T>
+inline bool Reference<T>::IsEmpty() const {
+  return _ref == nullptr;
+}
+
+template <typename T>
+inline T Reference<T>::Value() const {
+  if (_ref == nullptr) {
+    return T(_env, nullptr);
+  }
+
+  napi_value value;
+  napi_status status = napi_get_reference_value(_env, _ref, &value);
+  NAPI_THROW_IF_FAILED(_env, status, T());
+  return T(_env, value);
+}
+
+template <typename T>
+inline uint32_t Reference<T>::Ref() const {
+  uint32_t result;
+  napi_status status = napi_reference_ref(_env, _ref, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+template <typename T>
+inline uint32_t Reference<T>::Unref() const {
+  uint32_t result;
+  napi_status status = napi_reference_unref(_env, _ref, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+template <typename T>
+inline void Reference<T>::Reset() {
+  if (_ref != nullptr) {
+    napi_status status = napi_delete_reference(_env, _ref);
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+    _ref = nullptr;
+  }
+}
+
+template <typename T>
+inline void Reference<T>::Reset(const T& value, uint32_t refcount) {
+  Reset();
+  _env = value.Env();
+
+  napi_value val = value;
+  if (val != nullptr) {
+    napi_status status = napi_create_reference(_env, value, refcount, &_ref);
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+template <typename T>
+inline void Reference<T>::SuppressDestruct() {
+  _suppressDestruct = true;
+}
+
+template <typename T>
+inline Reference<T> Weak(T value) {
+  return Reference<T>::New(value, 0);
+}
+
+inline ObjectReference Weak(Object value) {
+  return Reference<Object>::New(value, 0);
+}
+
+inline FunctionReference Weak(Function value) {
+  return Reference<Function>::New(value, 0);
+}
+
+template <typename T>
+inline Reference<T> Persistent(T value) {
+  return Reference<T>::New(value, 1);
+}
+
+inline ObjectReference Persistent(Object value) {
+  return Reference<Object>::New(value, 1);
+}
+
+inline FunctionReference Persistent(Function value) {
+  return Reference<Function>::New(value, 1);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ObjectReference class
+////////////////////////////////////////////////////////////////////////////////
+
+inline ObjectReference::ObjectReference() : Reference<Object>() {}
+
+inline ObjectReference::ObjectReference(napi_env env, napi_ref ref)
+    : Reference<Object>(env, ref) {}
+
+inline ObjectReference::ObjectReference(Reference<Object>&& other)
+    : Reference<Object>(std::move(other)) {}
+
+inline ObjectReference& ObjectReference::operator=(Reference<Object>&& other) {
+  static_cast<Reference<Object>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline ObjectReference::ObjectReference(ObjectReference&& other)
+    : Reference<Object>(std::move(other)) {}
+
+inline ObjectReference& ObjectReference::operator=(ObjectReference&& other) {
+  static_cast<Reference<Object>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline ObjectReference::ObjectReference(const ObjectReference& other)
+    : Reference<Object>(other) {}
+
+inline MaybeOrValue<Napi::Value> ObjectReference::Get(
+    const char* utf8name) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Get(utf8name);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> ObjectReference::Get(
+    const std::string& utf8name) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Get(utf8name);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               napi_value value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               Napi::Value value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               const char* utf8value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, utf8value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               bool boolValue) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, boolValue);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               double numberValue) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, numberValue);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               napi_value value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               Napi::Value value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               std::string& utf8value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, utf8value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               bool boolValue) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, boolValue);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               double numberValue) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, numberValue);
+}
+
+inline MaybeOrValue<Napi::Value> ObjectReference::Get(uint32_t index) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Get(index);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               napi_value value) const {
+  HandleScope scope(_env);
+  return Value().Set(index, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               Napi::Value value) const {
+  HandleScope scope(_env);
+  return Value().Set(index, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               const char* utf8value) const {
+  HandleScope scope(_env);
+  return Value().Set(index, utf8value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(
+    uint32_t index, const std::string& utf8value) const {
+  HandleScope scope(_env);
+  return Value().Set(index, utf8value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               bool boolValue) const {
+  HandleScope scope(_env);
+  return Value().Set(index, boolValue);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               double numberValue) const {
+  HandleScope scope(_env);
+  return Value().Set(index, numberValue);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// FunctionReference class
+////////////////////////////////////////////////////////////////////////////////
+
+inline FunctionReference::FunctionReference() : Reference<Function>() {}
+
+inline FunctionReference::FunctionReference(napi_env env, napi_ref ref)
+    : Reference<Function>(env, ref) {}
+
+inline FunctionReference::FunctionReference(Reference<Function>&& other)
+    : Reference<Function>(std::move(other)) {}
+
+inline FunctionReference& FunctionReference::operator=(
+    Reference<Function>&& other) {
+  static_cast<Reference<Function>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline FunctionReference::FunctionReference(FunctionReference&& other)
+    : Reference<Function>(std::move(other)) {}
+
+inline FunctionReference& FunctionReference::operator=(
+    FunctionReference&& other) {
+  static_cast<Reference<Function>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::operator()(
+    const std::initializer_list<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value()(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    const std::initializer_list<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    const std::vector<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    napi_value recv, const std::initializer_list<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(recv, args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    napi_value recv, const std::vector<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(recv, args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    napi_value recv, size_t argc, const napi_value* args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(recv, argc, args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::MakeCallback(
+    napi_value recv,
+    const std::initializer_list<napi_value>& args,
+    napi_async_context context) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().MakeCallback(recv, args, context);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::MakeCallback(
+    napi_value recv,
+    const std::vector<napi_value>& args,
+    napi_async_context context) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().MakeCallback(recv, args, context);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::MakeCallback(
+    napi_value recv,
+    size_t argc,
+    const napi_value* args,
+    napi_async_context context) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result =
+      Value().MakeCallback(recv, argc, args, context);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Object> FunctionReference::New(
+    const std::initializer_list<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Object> result = Value().New(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()).As<Object>());
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Object();
+  }
+  return scope.Escape(result).As<Object>();
+#endif
+}
+
+inline MaybeOrValue<Object> FunctionReference::New(
+    const std::vector<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Object> result = Value().New(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()).As<Object>());
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Object();
+  }
+  return scope.Escape(result).As<Object>();
+#endif
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// CallbackInfo class
+////////////////////////////////////////////////////////////////////////////////
+
+inline CallbackInfo::CallbackInfo(napi_env env, napi_callback_info info)
+    : _env(env),
+      _info(info),
+      _this(nullptr),
+      _dynamicArgs(nullptr),
+      _data(nullptr) {
+  _argc = _staticArgCount;
+  _argv = _staticArgs;
+  napi_status status =
+      napi_get_cb_info(env, info, &_argc, _argv, &_this, &_data);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+
+  if (_argc > _staticArgCount) {
+    // Use either a fixed-size array (on the stack) or a dynamically-allocated
+    // array (on the heap) depending on the number of args.
+    _dynamicArgs = new napi_value[_argc];
+    _argv = _dynamicArgs;
+
+    status = napi_get_cb_info(env, info, &_argc, _argv, nullptr, nullptr);
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+inline CallbackInfo::~CallbackInfo() {
+  if (_dynamicArgs != nullptr) {
+    delete[] _dynamicArgs;
+  }
+}
+
+inline CallbackInfo::operator napi_callback_info() const {
+  return _info;
+}
+
+inline Value CallbackInfo::NewTarget() const {
+  napi_value newTarget;
+  napi_status status = napi_get_new_target(_env, _info, &newTarget);
+  NAPI_THROW_IF_FAILED(_env, status, Value());
+  return Value(_env, newTarget);
+}
+
+inline bool CallbackInfo::IsConstructCall() const {
+  return !NewTarget().IsEmpty();
+}
+
+inline Napi::Env CallbackInfo::Env() const {
+  return Napi::Env(_env);
+}
+
+inline size_t CallbackInfo::Length() const {
+  return _argc;
+}
+
+inline const Value CallbackInfo::operator[](size_t index) const {
+  return index < _argc ? Value(_env, _argv[index]) : Env().Undefined();
+}
+
+inline Value CallbackInfo::This() const {
+  if (_this == nullptr) {
+    return Env().Undefined();
+  }
+  return Object(_env, _this);
+}
+
+inline void* CallbackInfo::Data() const {
+  return _data;
+}
+
+inline void CallbackInfo::SetData(void* data) {
+  _data = data;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// PropertyDescriptor class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename PropertyDescriptor::GetterCallback Getter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+
+  desc.utf8name = utf8name;
+  desc.getter = details::TemplatedCallback<Getter>;
+  desc.attributes = attributes;
+  desc.data = data;
+
+  return desc;
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    const std::string& utf8name,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor<Getter>(utf8name.c_str(), attributes, data);
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    Name name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+
+  desc.name = name;
+  desc.getter = details::TemplatedCallback<Getter>;
+  desc.attributes = attributes;
+  desc.data = data;
+
+  return desc;
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter,
+          typename PropertyDescriptor::SetterCallback Setter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+
+  desc.utf8name = utf8name;
+  desc.getter = details::TemplatedCallback<Getter>;
+  desc.setter = details::TemplatedVoidCallback<Setter>;
+  desc.attributes = attributes;
+  desc.data = data;
+
+  return desc;
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter,
+          typename PropertyDescriptor::SetterCallback Setter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    const std::string& utf8name,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor<Getter, Setter>(utf8name.c_str(), attributes, data);
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter,
+          typename PropertyDescriptor::SetterCallback Setter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    Name name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+
+  desc.name = name;
+  desc.getter = details::TemplatedCallback<Getter>;
+  desc.setter = details::TemplatedVoidCallback<Setter>;
+  desc.attributes = attributes;
+  desc.data = data;
+
+  return desc;
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    const char* utf8name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* data) {
+  using CbData = details::CallbackData<Getter, Napi::Value>;
+  auto callbackData = new CbData({getter, data});
+
+  napi_status status = AttachData(env, object, callbackData);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, napi_property_descriptor());
+  }
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    const std::string& utf8name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor(env, object, utf8name.c_str(), getter, attributes, data);
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    Name name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* data) {
+  using CbData = details::CallbackData<Getter, Napi::Value>;
+  auto callbackData = new CbData({getter, data});
+
+  napi_status status = AttachData(env, object, callbackData);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, napi_property_descriptor());
+  }
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    const char* utf8name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  using CbData = details::AccessorCallbackData<Getter, Setter>;
+  auto callbackData = new CbData({getter, setter, data});
+
+  napi_status status = AttachData(env, object, callbackData);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, napi_property_descriptor());
+  }
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             CbData::GetterWrapper,
+                             CbData::SetterWrapper,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    const std::string& utf8name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor(
+      env, object, utf8name.c_str(), getter, setter, attributes, data);
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    Name name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  using CbData = details::AccessorCallbackData<Getter, Setter>;
+  auto callbackData = new CbData({getter, setter, data});
+
+  napi_status status = AttachData(env, object, callbackData);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, napi_property_descriptor());
+  }
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             CbData::GetterWrapper,
+                             CbData::SetterWrapper,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    Napi::Env env,
+    Napi::Object /*object*/,
+    const char* utf8name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* data) {
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             Napi::Function::New(env, cb, utf8name, data),
+                             attributes,
+                             nullptr});
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    Napi::Env env,
+    Napi::Object object,
+    const std::string& utf8name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* data) {
+  return Function(env, object, utf8name.c_str(), cb, attributes, data);
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    Napi::Env env,
+    Napi::Object /*object*/,
+    Name name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* data) {
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             Napi::Function::New(env, cb, nullptr, data),
+                             attributes,
+                             nullptr});
+}
+
+inline PropertyDescriptor PropertyDescriptor::Value(
+    const char* utf8name,
+    napi_value value,
+    napi_property_attributes attributes) {
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             value,
+                             attributes,
+                             nullptr});
+}
+
+inline PropertyDescriptor PropertyDescriptor::Value(
+    const std::string& utf8name,
+    napi_value value,
+    napi_property_attributes attributes) {
+  return Value(utf8name.c_str(), value, attributes);
+}
+
+inline PropertyDescriptor PropertyDescriptor::Value(
+    napi_value name, napi_value value, napi_property_attributes attributes) {
+  return PropertyDescriptor(
+      {nullptr, name, nullptr, nullptr, nullptr, value, attributes, nullptr});
+}
+
+inline PropertyDescriptor PropertyDescriptor::Value(
+    Name name, Napi::Value value, napi_property_attributes attributes) {
+  napi_value nameValue = name;
+  napi_value valueValue = value;
+  return PropertyDescriptor::Value(nameValue, valueValue, attributes);
+}
+
+inline PropertyDescriptor::PropertyDescriptor(napi_property_descriptor desc)
+    : _desc(desc) {}
+
+inline PropertyDescriptor::operator napi_property_descriptor&() {
+  return _desc;
+}
+
+inline PropertyDescriptor::operator const napi_property_descriptor&() const {
+  return _desc;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// InstanceWrap<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline void InstanceWrap<T>::AttachPropData(
+    napi_env env, napi_value value, const napi_property_descriptor* prop) {
+  napi_status status;
+  if (!(prop->attributes & napi_static)) {
+    if (prop->method == T::InstanceVoidMethodCallbackWrapper) {
+      status = Napi::details::AttachData(
+          env, value, static_cast<InstanceVoidMethodCallbackData*>(prop->data));
+      NAPI_THROW_IF_FAILED_VOID(env, status);
+    } else if (prop->method == T::InstanceMethodCallbackWrapper) {
+      status = Napi::details::AttachData(
+          env, value, static_cast<InstanceMethodCallbackData*>(prop->data));
+      NAPI_THROW_IF_FAILED_VOID(env, status);
+    } else if (prop->getter == T::InstanceGetterCallbackWrapper ||
+               prop->setter == T::InstanceSetterCallbackWrapper) {
+      status = Napi::details::AttachData(
+          env, value, static_cast<InstanceAccessorCallbackData*>(prop->data));
+      NAPI_THROW_IF_FAILED_VOID(env, status);
+    }
+  }
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    const char* utf8name,
+    InstanceVoidMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceVoidMethodCallbackData* callbackData =
+      new InstanceVoidMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = T::InstanceVoidMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    const char* utf8name,
+    InstanceMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceMethodCallbackData* callbackData =
+      new InstanceMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = T::InstanceMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    Symbol name,
+    InstanceVoidMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceVoidMethodCallbackData* callbackData =
+      new InstanceVoidMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = T::InstanceVoidMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    Symbol name,
+    InstanceMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceMethodCallbackData* callbackData =
+      new InstanceMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = T::InstanceMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceVoidMethodCallback method>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = details::TemplatedInstanceVoidCallback<T, method>;
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceMethodCallback method>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = details::TemplatedInstanceCallback<T, method>;
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceVoidMethodCallback method>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = details::TemplatedInstanceVoidCallback<T, method>;
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceMethodCallback method>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = details::TemplatedInstanceCallback<T, method>;
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceAccessor(
+    const char* utf8name,
+    InstanceGetterCallback getter,
+    InstanceSetterCallback setter,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceAccessorCallbackData* callbackData =
+      new InstanceAccessorCallbackData({getter, setter, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.getter = getter != nullptr ? T::InstanceGetterCallbackWrapper : nullptr;
+  desc.setter = setter != nullptr ? T::InstanceSetterCallbackWrapper : nullptr;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceAccessor(
+    Symbol name,
+    InstanceGetterCallback getter,
+    InstanceSetterCallback setter,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceAccessorCallbackData* callbackData =
+      new InstanceAccessorCallbackData({getter, setter, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.getter = getter != nullptr ? T::InstanceGetterCallbackWrapper : nullptr;
+  desc.setter = setter != nullptr ? T::InstanceSetterCallbackWrapper : nullptr;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceGetterCallback getter,
+          typename InstanceWrap<T>::InstanceSetterCallback setter>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceAccessor(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.getter = details::TemplatedInstanceCallback<T, getter>;
+  desc.setter = This::WrapSetter(This::SetterTag<setter>());
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceGetterCallback getter,
+          typename InstanceWrap<T>::InstanceSetterCallback setter>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceAccessor(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.getter = details::TemplatedInstanceCallback<T, getter>;
+  desc.setter = This::WrapSetter(This::SetterTag<setter>());
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceValue(
+    const char* utf8name,
+    Napi::Value value,
+    napi_property_attributes attributes) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.value = value;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceValue(
+    Symbol name, Napi::Value value, napi_property_attributes attributes) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.value = value;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline napi_value InstanceWrap<T>::InstanceVoidMethodCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo callbackInfo(env, info);
+    InstanceVoidMethodCallbackData* callbackData =
+        reinterpret_cast<InstanceVoidMethodCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    T* instance = T::Unwrap(callbackInfo.This().As<Object>());
+    auto cb = callbackData->callback;
+    if (instance) (instance->*cb)(callbackInfo);
+    return nullptr;
+  });
+}
+
+template <typename T>
+inline napi_value InstanceWrap<T>::InstanceMethodCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo callbackInfo(env, info);
+    InstanceMethodCallbackData* callbackData =
+        reinterpret_cast<InstanceMethodCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    T* instance = T::Unwrap(callbackInfo.This().As<Object>());
+    auto cb = callbackData->callback;
+    return instance ? (instance->*cb)(callbackInfo) : Napi::Value();
+  });
+}
+
+template <typename T>
+inline napi_value InstanceWrap<T>::InstanceGetterCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo callbackInfo(env, info);
+    InstanceAccessorCallbackData* callbackData =
+        reinterpret_cast<InstanceAccessorCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    T* instance = T::Unwrap(callbackInfo.This().As<Object>());
+    auto cb = callbackData->getterCallback;
+    return instance ? (instance->*cb)(callbackInfo) : Napi::Value();
+  });
+}
+
+template <typename T>
+inline napi_value InstanceWrap<T>::InstanceSetterCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo callbackInfo(env, info);
+    InstanceAccessorCallbackData* callbackData =
+        reinterpret_cast<InstanceAccessorCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    T* instance = T::Unwrap(callbackInfo.This().As<Object>());
+    auto cb = callbackData->setterCallback;
+    if (instance) (instance->*cb)(callbackInfo, callbackInfo[0]);
+    return nullptr;
+  });
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceSetterCallback method>
+inline napi_value InstanceWrap<T>::WrappedMethod(
+    napi_env env, napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback(env, [&] {
+    const CallbackInfo cbInfo(env, info);
+    T* instance = T::Unwrap(cbInfo.This().As<Object>());
+    if (instance) (instance->*method)(cbInfo, cbInfo[0]);
+    return nullptr;
+  });
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ObjectWrap<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline ObjectWrap<T>::ObjectWrap(const Napi::CallbackInfo& callbackInfo) {
+  napi_env env = callbackInfo.Env();
+  napi_value wrapper = callbackInfo.This();
+  napi_status status;
+  napi_ref ref;
+  T* instance = static_cast<T*>(this);
+  status = napi_wrap(env, wrapper, instance, FinalizeCallback, nullptr, &ref);
+  NAPI_THROW_IF_FAILED_VOID(env, status);
+
+  Reference<Object>* instanceRef = instance;
+  *instanceRef = Reference<Object>(env, ref);
+}
+
+template <typename T>
+inline ObjectWrap<T>::~ObjectWrap() {
+  // If the JS object still exists at this point, remove the finalizer added
+  // through `napi_wrap()`.
+  if (!IsEmpty() && !_finalized) {
+    Object object = Value();
+    // It is not valid to call `napi_remove_wrap()` with an empty `object`.
+    // This happens e.g. during garbage collection.
+    if (!object.IsEmpty() && _construction_failed) {
+      napi_remove_wrap(Env(), object, nullptr);
+    }
+  }
+}
+
+template <typename T>
+inline T* ObjectWrap<T>::Unwrap(Object wrapper) {
+  void* unwrapped;
+  napi_status status = napi_unwrap(wrapper.Env(), wrapper, &unwrapped);
+  NAPI_THROW_IF_FAILED(wrapper.Env(), status, nullptr);
+  return static_cast<T*>(unwrapped);
+}
+
+template <typename T>
+inline Function ObjectWrap<T>::DefineClass(
+    Napi::Env env,
+    const char* utf8name,
+    const size_t props_count,
+    const napi_property_descriptor* descriptors,
+    void* data) {
+  napi_status status;
+  std::vector<napi_property_descriptor> props(props_count);
+
+  // We copy the descriptors to a local array because before defining the class
+  // we must replace static method property descriptors with value property
+  // descriptors such that the value is a function-valued `napi_value` created
+  // with `CreateFunction()`.
+  //
+  // This replacement could be made for instance methods as well, but V8 aborts
+  // if we do that, because it expects methods defined on the prototype template
+  // to have `FunctionTemplate`s.
+  for (size_t index = 0; index < props_count; index++) {
+    props[index] = descriptors[index];
+    napi_property_descriptor* prop = &props[index];
+    if (prop->method == T::StaticMethodCallbackWrapper) {
+      status =
+          CreateFunction(env,
+                         utf8name,
+                         prop->method,
+                         static_cast<StaticMethodCallbackData*>(prop->data),
+                         &(prop->value));
+      NAPI_THROW_IF_FAILED(env, status, Function());
+      prop->method = nullptr;
+      prop->data = nullptr;
+    } else if (prop->method == T::StaticVoidMethodCallbackWrapper) {
+      status =
+          CreateFunction(env,
+                         utf8name,
+                         prop->method,
+                         static_cast<StaticVoidMethodCallbackData*>(prop->data),
+                         &(prop->value));
+      NAPI_THROW_IF_FAILED(env, status, Function());
+      prop->method = nullptr;
+      prop->data = nullptr;
+    }
+  }
+
+  napi_value value;
+  status = napi_define_class(env,
+                             utf8name,
+                             NAPI_AUTO_LENGTH,
+                             T::ConstructorCallbackWrapper,
+                             data,
+                             props_count,
+                             props.data(),
+                             &value);
+  NAPI_THROW_IF_FAILED(env, status, Function());
+
+  // After defining the class we iterate once more over the property descriptors
+  // and attach the data associated with accessors and instance methods to the
+  // newly created JavaScript class.
+  for (size_t idx = 0; idx < props_count; idx++) {
+    const napi_property_descriptor* prop = &props[idx];
+
+    if (prop->getter == T::StaticGetterCallbackWrapper ||
+        prop->setter == T::StaticSetterCallbackWrapper) {
+      status = Napi::details::AttachData(
+          env, value, static_cast<StaticAccessorCallbackData*>(prop->data));
+      NAPI_THROW_IF_FAILED(env, status, Function());
+    } else {
+      // InstanceWrap<T>::AttachPropData is responsible for attaching the data
+      // of instance methods and accessors.
+      T::AttachPropData(env, value, prop);
+    }
+  }
+
+  return Function(env, value);
+}
+
+template <typename T>
+inline Function ObjectWrap<T>::DefineClass(
+    Napi::Env env,
+    const char* utf8name,
+    const std::initializer_list<ClassPropertyDescriptor<T>>& properties,
+    void* data) {
+  return DefineClass(
+      env,
+      utf8name,
+      properties.size(),
+      reinterpret_cast<const napi_property_descriptor*>(properties.begin()),
+      data);
+}
+
+template <typename T>
+inline Function ObjectWrap<T>::DefineClass(
+    Napi::Env env,
+    const char* utf8name,
+    const std::vector<ClassPropertyDescriptor<T>>& properties,
+    void* data) {
+  return DefineClass(
+      env,
+      utf8name,
+      properties.size(),
+      reinterpret_cast<const napi_property_descriptor*>(properties.data()),
+      data);
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    const char* utf8name,
+    StaticVoidMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticVoidMethodCallbackData* callbackData =
+      new StaticVoidMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = T::StaticVoidMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    const char* utf8name,
+    StaticMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticMethodCallbackData* callbackData =
+      new StaticMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = T::StaticMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    Symbol name,
+    StaticVoidMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticVoidMethodCallbackData* callbackData =
+      new StaticVoidMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = T::StaticVoidMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    Symbol name,
+    StaticMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticMethodCallbackData* callbackData =
+      new StaticMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = T::StaticMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticVoidMethodCallback method>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = details::TemplatedVoidCallback<method>;
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticVoidMethodCallback method>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = details::TemplatedVoidCallback<method>;
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticMethodCallback method>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = details::TemplatedCallback<method>;
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticMethodCallback method>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = details::TemplatedCallback<method>;
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticAccessor(
+    const char* utf8name,
+    StaticGetterCallback getter,
+    StaticSetterCallback setter,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticAccessorCallbackData* callbackData =
+      new StaticAccessorCallbackData({getter, setter, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.getter = getter != nullptr ? T::StaticGetterCallbackWrapper : nullptr;
+  desc.setter = setter != nullptr ? T::StaticSetterCallbackWrapper : nullptr;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticAccessor(
+    Symbol name,
+    StaticGetterCallback getter,
+    StaticSetterCallback setter,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticAccessorCallbackData* callbackData =
+      new StaticAccessorCallbackData({getter, setter, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.getter = getter != nullptr ? T::StaticGetterCallbackWrapper : nullptr;
+  desc.setter = setter != nullptr ? T::StaticSetterCallbackWrapper : nullptr;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticGetterCallback getter,
+          typename ObjectWrap<T>::StaticSetterCallback setter>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticAccessor(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.getter = details::TemplatedCallback<getter>;
+  desc.setter = This::WrapStaticSetter(This::StaticSetterTag<setter>());
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticGetterCallback getter,
+          typename ObjectWrap<T>::StaticSetterCallback setter>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticAccessor(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.getter = details::TemplatedCallback<getter>;
+  desc.setter = This::WrapStaticSetter(This::StaticSetterTag<setter>());
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticValue(
+    const char* utf8name,
+    Napi::Value value,
+    napi_property_attributes attributes) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.value = value;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticValue(
+    Symbol name, Napi::Value value, napi_property_attributes attributes) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.value = value;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline Value ObjectWrap<T>::OnCalledAsFunction(
+    const Napi::CallbackInfo& callbackInfo) {
+  NAPI_THROW(
+      TypeError::New(callbackInfo.Env(),
+                     "Class constructors cannot be invoked without 'new'"),
+      Napi::Value());
+}
+
+template <typename T>
+inline void ObjectWrap<T>::Finalize(Napi::Env /*env*/) {}
+
+template <typename T>
+inline void ObjectWrap<T>::Finalize(BasicEnv /*env*/) {}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::ConstructorCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  napi_value new_target;
+  napi_status status = napi_get_new_target(env, info, &new_target);
+  if (status != napi_ok) return nullptr;
+
+  bool isConstructCall = (new_target != nullptr);
+  if (!isConstructCall) {
+    return details::WrapCallback(
+        env, [&] { return T::OnCalledAsFunction(CallbackInfo(env, info)); });
+  }
+
+  napi_value wrapper = details::WrapCallback(env, [&] {
+    CallbackInfo callbackInfo(env, info);
+    T* instance = new T(callbackInfo);
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+    instance->_construction_failed = false;
+#else
+    if (callbackInfo.Env().IsExceptionPending()) {
+      // We need to clear the exception so that removing the wrap might work.
+      Error e = callbackInfo.Env().GetAndClearPendingException();
+      delete instance;
+      e.ThrowAsJavaScriptException();
+    } else {
+      instance->_construction_failed = false;
+    }
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+    return callbackInfo.This();
+  });
+
+  return wrapper;
+}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::StaticVoidMethodCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo callbackInfo(env, info);
+    StaticVoidMethodCallbackData* callbackData =
+        reinterpret_cast<StaticVoidMethodCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    callbackData->callback(callbackInfo);
+    return nullptr;
+  });
+}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::StaticMethodCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo callbackInfo(env, info);
+    StaticMethodCallbackData* callbackData =
+        reinterpret_cast<StaticMethodCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    return callbackData->callback(callbackInfo);
+  });
+}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::StaticGetterCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo callbackInfo(env, info);
+    StaticAccessorCallbackData* callbackData =
+        reinterpret_cast<StaticAccessorCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    return callbackData->getterCallback(callbackInfo);
+  });
+}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::StaticSetterCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback(env, [&] {
+    CallbackInfo callbackInfo(env, info);
+    StaticAccessorCallbackData* callbackData =
+        reinterpret_cast<StaticAccessorCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    callbackData->setterCallback(callbackInfo, callbackInfo[0]);
+    return nullptr;
+  });
+}
+
+template <typename T>
+inline void ObjectWrap<T>::FinalizeCallback(node_addon_api_basic_env env,
+                                            void* data,
+                                            void* /*hint*/) {
+  // If the child class does not override _any_ Finalize() method, `env` will be
+  // unused because of the constexpr guards. Explicitly reference it here to
+  // bypass compiler warnings.
+  (void)env;
+  T* instance = static_cast<T*>(data);
+
+  // Prevent ~ObjectWrap from calling napi_remove_wrap.
+  // The instance->_ref should be deleted with napi_delete_reference in
+  // ~Reference.
+  instance->_finalized = true;
+
+  // If class overrides the basic finalizer, execute it.
+  if constexpr (details::HasBasicFinalizer<T>::value) {
+#ifndef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+    HandleScope scope(env);
+#endif
+
+    instance->Finalize(Napi::BasicEnv(env));
+  }
+
+  // If class overrides the (extended) finalizer, either schedule it or
+  // execute it immediately (depending on experimental features enabled).
+  if constexpr (details::HasExtendedFinalizer<T>::value) {
+#ifdef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+    // In experimental, attach via node_api_post_finalizer.
+    // `PostFinalizeCallback` is responsible for deleting the `T* instance`,
+    // after calling the user-provided finalizer.
+    napi_status status =
+        node_api_post_finalizer(env, PostFinalizeCallback, data, nullptr);
+    NAPI_FATAL_IF_FAILED(status,
+                         "ObjectWrap<T>::FinalizeCallback",
+                         "node_api_post_finalizer failed");
+#else
+    // In non-experimental, this `FinalizeCallback` already executes from a
+    // non-basic environment. Execute the override directly.
+    // `PostFinalizeCallback` is responsible for deleting the `T* instance`,
+    // after calling the user-provided finalizer.
+    HandleScope scope(env);
+    PostFinalizeCallback(env, data, static_cast<void*>(nullptr));
+#endif
+  }
+  // If the instance does _not_ override the (extended) finalizer, delete the
+  // `T* instance` immediately.
+  else {
+    delete instance;
+  }
+}
+
+template <typename T>
+inline void ObjectWrap<T>::PostFinalizeCallback(napi_env env,
+                                                void* data,
+                                                void* /*hint*/) {
+  T* instance = static_cast<T*>(data);
+  instance->Finalize(Napi::Env(env));
+  delete instance;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticSetterCallback method>
+inline napi_value ObjectWrap<T>::WrappedMethod(
+    napi_env env, napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback(env, [&] {
+    const CallbackInfo cbInfo(env, info);
+    // MSVC requires to copy 'method' function pointer to a local variable
+    // before invoking it.
+    auto m = method;
+    m(cbInfo, cbInfo[0]);
+    return nullptr;
+  });
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// HandleScope class
+////////////////////////////////////////////////////////////////////////////////
+
+inline HandleScope::HandleScope(napi_env env, napi_handle_scope scope)
+    : _env(env), _scope(scope) {}
+
+inline HandleScope::HandleScope(Napi::Env env) : _env(env) {
+  napi_status status = napi_open_handle_scope(_env, &_scope);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline HandleScope::~HandleScope() {
+  napi_status status = napi_close_handle_scope(_env, _scope);
+  NAPI_FATAL_IF_FAILED(
+      status, "HandleScope::~HandleScope", "napi_close_handle_scope");
+}
+
+inline HandleScope::operator napi_handle_scope() const {
+  return _scope;
+}
+
+inline Napi::Env HandleScope::Env() const {
+  return Napi::Env(_env);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// EscapableHandleScope class
+////////////////////////////////////////////////////////////////////////////////
+
+inline EscapableHandleScope::EscapableHandleScope(
+    napi_env env, napi_escapable_handle_scope scope)
+    : _env(env), _scope(scope) {}
+
+inline EscapableHandleScope::EscapableHandleScope(Napi::Env env) : _env(env) {
+  napi_status status = napi_open_escapable_handle_scope(_env, &_scope);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline EscapableHandleScope::~EscapableHandleScope() {
+  napi_status status = napi_close_escapable_handle_scope(_env, _scope);
+  NAPI_FATAL_IF_FAILED(status,
+                       "EscapableHandleScope::~EscapableHandleScope",
+                       "napi_close_escapable_handle_scope");
+}
+
+inline EscapableHandleScope::operator napi_escapable_handle_scope() const {
+  return _scope;
+}
+
+inline Napi::Env EscapableHandleScope::Env() const {
+  return Napi::Env(_env);
+}
+
+inline Value EscapableHandleScope::Escape(napi_value escapee) {
+  napi_value result;
+  napi_status status = napi_escape_handle(_env, _scope, escapee, &result);
+  NAPI_THROW_IF_FAILED(_env, status, Value());
+  return Value(_env, result);
+}
+
+#if (NAPI_VERSION > 2)
+////////////////////////////////////////////////////////////////////////////////
+// CallbackScope class
+////////////////////////////////////////////////////////////////////////////////
+
+inline CallbackScope::CallbackScope(napi_env env, napi_callback_scope scope)
+    : _env(env), _scope(scope) {}
+
+inline CallbackScope::CallbackScope(napi_env env, napi_async_context context)
+    : _env(env) {
+  napi_status status =
+      napi_open_callback_scope(_env, Object::New(env), context, &_scope);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline CallbackScope::~CallbackScope() {
+  napi_status status = napi_close_callback_scope(_env, _scope);
+  NAPI_FATAL_IF_FAILED(
+      status, "CallbackScope::~CallbackScope", "napi_close_callback_scope");
+}
+
+inline CallbackScope::operator napi_callback_scope() const {
+  return _scope;
+}
+
+inline Napi::Env CallbackScope::Env() const {
+  return Napi::Env(_env);
+}
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// AsyncContext class
+////////////////////////////////////////////////////////////////////////////////
+
+inline AsyncContext::AsyncContext(napi_env env, const char* resource_name)
+    : AsyncContext(env, resource_name, Object::New(env)) {}
+
+inline AsyncContext::AsyncContext(napi_env env,
+                                  const char* resource_name,
+                                  const Object& resource)
+    : _env(env), _context(nullptr) {
+  napi_value resource_id;
+  napi_status status = napi_create_string_utf8(
+      _env, resource_name, NAPI_AUTO_LENGTH, &resource_id);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+
+  status = napi_async_init(_env, resource, resource_id, &_context);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline AsyncContext::~AsyncContext() {
+  if (_context != nullptr) {
+    napi_async_destroy(_env, _context);
+    _context = nullptr;
+  }
+}
+
+inline AsyncContext::AsyncContext(AsyncContext&& other) {
+  _env = other._env;
+  other._env = nullptr;
+  _context = other._context;
+  other._context = nullptr;
+}
+
+inline AsyncContext& AsyncContext::operator=(AsyncContext&& other) {
+  _env = other._env;
+  other._env = nullptr;
+  _context = other._context;
+  other._context = nullptr;
+  return *this;
+}
+
+inline AsyncContext::operator napi_async_context() const {
+  return _context;
+}
+
+inline Napi::Env AsyncContext::Env() const {
+  return Napi::Env(_env);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// AsyncWorker class
+////////////////////////////////////////////////////////////////////////////////
+
+#if NAPI_HAS_THREADS
+
+inline AsyncWorker::AsyncWorker(const Function& callback)
+    : AsyncWorker(callback, "generic") {}
+
+inline AsyncWorker::AsyncWorker(const Function& callback,
+                                const char* resource_name)
+    : AsyncWorker(callback, resource_name, Object::New(callback.Env())) {}
+
+inline AsyncWorker::AsyncWorker(const Function& callback,
+                                const char* resource_name,
+                                const Object& resource)
+    : AsyncWorker(
+          Object::New(callback.Env()), callback, resource_name, resource) {}
+
+inline AsyncWorker::AsyncWorker(const Object& receiver,
+                                const Function& callback)
+    : AsyncWorker(receiver, callback, "generic") {}
+
+inline AsyncWorker::AsyncWorker(const Object& receiver,
+                                const Function& callback,
+                                const char* resource_name)
+    : AsyncWorker(
+          receiver, callback, resource_name, Object::New(callback.Env())) {}
+
+inline AsyncWorker::AsyncWorker(const Object& receiver,
+                                const Function& callback,
+                                const char* resource_name,
+                                const Object& resource)
+    : _env(callback.Env()),
+      _receiver(Napi::Persistent(receiver)),
+      _callback(Napi::Persistent(callback)),
+      _suppress_destruct(false) {
+  napi_value resource_id;
+  napi_status status = napi_create_string_latin1(
+      _env, resource_name, NAPI_AUTO_LENGTH, &resource_id);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+
+  status = napi_create_async_work(_env,
+                                  resource,
+                                  resource_id,
+                                  OnAsyncWorkExecute,
+                                  OnAsyncWorkComplete,
+                                  this,
+                                  &_work);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline AsyncWorker::AsyncWorker(Napi::Env env) : AsyncWorker(env, "generic") {}
+
+inline AsyncWorker::AsyncWorker(Napi::Env env, const char* resource_name)
+    : AsyncWorker(env, resource_name, Object::New(env)) {}
+
+inline AsyncWorker::AsyncWorker(Napi::Env env,
+                                const char* resource_name,
+                                const Object& resource)
+    : _env(env), _receiver(), _callback(), _suppress_destruct(false) {
+  napi_value resource_id;
+  napi_status status = napi_create_string_latin1(
+      _env, resource_name, NAPI_AUTO_LENGTH, &resource_id);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+
+  status = napi_create_async_work(_env,
+                                  resource,
+                                  resource_id,
+                                  OnAsyncWorkExecute,
+                                  OnAsyncWorkComplete,
+                                  this,
+                                  &_work);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline AsyncWorker::~AsyncWorker() {
+  if (_work != nullptr) {
+    napi_delete_async_work(_env, _work);
+    _work = nullptr;
+  }
+}
+
+inline void AsyncWorker::Destroy() {
+  delete this;
+}
+
+inline AsyncWorker::operator napi_async_work() const {
+  return _work;
+}
+
+inline Napi::Env AsyncWorker::Env() const {
+  return Napi::Env(_env);
+}
+
+inline void AsyncWorker::Queue() {
+  napi_status status = napi_queue_async_work(_env, _work);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline void AsyncWorker::Cancel() {
+  napi_status status = napi_cancel_async_work(_env, _work);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline ObjectReference& AsyncWorker::Receiver() {
+  return _receiver;
+}
+
+inline FunctionReference& AsyncWorker::Callback() {
+  return _callback;
+}
+
+inline void AsyncWorker::SuppressDestruct() {
+  _suppress_destruct = true;
+}
+
+inline void AsyncWorker::OnOK() {
+  if (!_callback.IsEmpty()) {
+    _callback.Call(_receiver.Value(), GetResult(_callback.Env()));
+  }
+}
+
+inline void AsyncWorker::OnError(const Error& e) {
+  if (!_callback.IsEmpty()) {
+    _callback.Call(_receiver.Value(),
+                   std::initializer_list<napi_value>{e.Value()});
+  }
+}
+
+inline void AsyncWorker::SetError(const std::string& error) {
+  _error = error;
+}
+
+inline std::vector<napi_value> AsyncWorker::GetResult(Napi::Env /*env*/) {
+  return {};
+}
+// The OnAsyncWorkExecute method receives an napi_env argument. However, do NOT
+// use it within this method, as it does not run on the JavaScript thread and
+// must not run any method that would cause JavaScript to run. In practice,
+// this means that almost any use of napi_env will be incorrect.
+inline void AsyncWorker::OnAsyncWorkExecute(napi_env env, void* asyncworker) {
+  AsyncWorker* self = static_cast<AsyncWorker*>(asyncworker);
+  self->OnExecute(env);
+}
+// The OnExecute method receives an napi_env argument. However, do NOT
+// use it within this method, as it does not run on the JavaScript thread and
+// must not run any method that would cause JavaScript to run. In practice,
+// this means that almost any use of napi_env will be incorrect.
+inline void AsyncWorker::OnExecute(Napi::Env /*DO_NOT_USE*/) {
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+  try {
+    Execute();
+  } catch (const std::exception& e) {
+    SetError(e.what());
+  }
+#else   // NODE_ADDON_API_CPP_EXCEPTIONS
+  Execute();
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+}
+
+inline void AsyncWorker::OnAsyncWorkComplete(napi_env env,
+                                             napi_status status,
+                                             void* asyncworker) {
+  AsyncWorker* self = static_cast<AsyncWorker*>(asyncworker);
+  self->OnWorkComplete(env, status);
+}
+inline void AsyncWorker::OnWorkComplete(Napi::Env env, napi_status status) {
+  if (status != napi_cancelled) {
+    HandleScope scope(_env);
+    details::WrapCallback(env, [&] {
+      if (_error.size() == 0) {
+        OnOK();
+      } else {
+        OnError(Error::New(_env, _error));
+      }
+      return nullptr;
+    });
+  }
+  if (!_suppress_destruct) {
+    Destroy();
+  }
+}
+
+#endif  // NAPI_HAS_THREADS
+
+#if (NAPI_VERSION > 3 && NAPI_HAS_THREADS)
+////////////////////////////////////////////////////////////////////////////////
+// TypedThreadSafeFunction<ContextType,DataType,CallJs> class
+////////////////////////////////////////////////////////////////////////////////
+
+// Starting with NAPI 5, the JavaScript function `func` parameter of
+// `napi_create_threadsafe_function` is optional.
+#if NAPI_VERSION > 4
+// static, with Callback [missing] Resource [missing] Finalizer [missing]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      nullptr,
+                                      nullptr,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      nullptr,
+                                      nullptr,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [missing] Resource [passed] Finalizer [missing]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Object& resource,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      nullptr,
+                                      resource,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      nullptr,
+                                      nullptr,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [missing] Resource [missing] Finalizer [passed]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context,
+    Finalizer finalizeCallback,
+    FinalizerDataType* data) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  auto fini =
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext;
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      nullptr,
+                                      nullptr,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      finalizeData,
+                                      fini,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [missing] Resource [passed] Finalizer [passed]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Object& resource,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context,
+    Finalizer finalizeCallback,
+    FinalizerDataType* data) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  auto fini =
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext;
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      nullptr,
+                                      resource,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      finalizeData,
+                                      fini,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+#endif
+
+// static, with Callback [passed] Resource [missing] Finalizer [missing]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Function& callback,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      callback,
+                                      nullptr,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      nullptr,
+                                      nullptr,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [passed] Resource [passed] Finalizer [missing]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Function& callback,
+    const Object& resource,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      callback,
+                                      resource,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      nullptr,
+                                      nullptr,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [passed] Resource [missing] Finalizer [passed]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Function& callback,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context,
+    Finalizer finalizeCallback,
+    FinalizerDataType* data) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  auto fini =
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext;
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      callback,
+                                      nullptr,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      finalizeData,
+                                      fini,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with: Callback [passed] Resource [passed] Finalizer [passed]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename CallbackType,
+          typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    CallbackType callback,
+    const Object& resource,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context,
+    Finalizer finalizeCallback,
+    FinalizerDataType* data) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  auto fini =
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext;
+  napi_status status = napi_create_threadsafe_function(
+      env,
+      details::DefaultCallbackWrapper<
+          CallbackType,
+          TypedThreadSafeFunction<ContextType, DataType, CallJs>>(env,
+                                                                  callback),
+      resource,
+      String::From(env, resourceName),
+      maxQueueSize,
+      initialThreadCount,
+      finalizeData,
+      fini,
+      context,
+      CallJsInternal,
+      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>::
+    TypedThreadSafeFunction()
+    : _tsfn() {}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>::
+    TypedThreadSafeFunction(napi_threadsafe_function tsfn)
+    : _tsfn(tsfn) {}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>::
+operator napi_threadsafe_function() const {
+  return _tsfn;
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::BlockingCall(
+    DataType* data) const {
+  return napi_call_threadsafe_function(_tsfn, data, napi_tsfn_blocking);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::NonBlockingCall(
+    DataType* data) const {
+  return napi_call_threadsafe_function(_tsfn, data, napi_tsfn_nonblocking);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline void TypedThreadSafeFunction<ContextType, DataType, CallJs>::Ref(
+    napi_env env) const {
+  if (_tsfn != nullptr) {
+    napi_status status = napi_ref_threadsafe_function(env, _tsfn);
+    NAPI_THROW_IF_FAILED_VOID(env, status);
+  }
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline void TypedThreadSafeFunction<ContextType, DataType, CallJs>::Unref(
+    napi_env env) const {
+  if (_tsfn != nullptr) {
+    napi_status status = napi_unref_threadsafe_function(env, _tsfn);
+    NAPI_THROW_IF_FAILED_VOID(env, status);
+  }
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::Acquire() const {
+  return napi_acquire_threadsafe_function(_tsfn);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::Release() const {
+  return napi_release_threadsafe_function(_tsfn, napi_tsfn_release);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::Abort() const {
+  return napi_release_threadsafe_function(_tsfn, napi_tsfn_abort);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline ContextType*
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::GetContext() const {
+  void* context;
+  napi_status status = napi_get_threadsafe_function_context(_tsfn, &context);
+  NAPI_FATAL_IF_FAILED(status,
+                       "TypedThreadSafeFunction::GetContext",
+                       "napi_get_threadsafe_function_context");
+  return static_cast<ContextType*>(context);
+}
+
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+void TypedThreadSafeFunction<ContextType, DataType, CallJs>::CallJsInternal(
+    napi_env env, napi_value jsCallback, void* context, void* data) {
+  details::CallJsWrapper<ContextType, DataType, decltype(CallJs), CallJs>(
+      env, jsCallback, context, data);
+}
+
+#if NAPI_VERSION == 4
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+Napi::Function
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::EmptyFunctionFactory(
+    Napi::Env env) {
+  return Napi::Function::New(env, [](const CallbackInfo& cb) {});
+}
+
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+Napi::Function
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::FunctionOrEmpty(
+    Napi::Env env, Napi::Function& callback) {
+  if (callback.IsEmpty()) {
+    return EmptyFunctionFactory(env);
+  }
+  return callback;
+}
+
+#else
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+std::nullptr_t
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::EmptyFunctionFactory(
+    Napi::Env /*env*/) {
+  return nullptr;
+}
+
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+Napi::Function
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::FunctionOrEmpty(
+    Napi::Env /*env*/, Napi::Function& callback) {
+  return callback;
+}
+
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// ThreadSafeFunction class
+////////////////////////////////////////////////////////////////////////////////
+
+// static
+template <typename ResourceString>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount) {
+  return New(
+      env, callback, Object(), resourceName, maxQueueSize, initialThreadCount);
+}
+
+// static
+template <typename ResourceString, typename ContextType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             context);
+}
+
+// static
+template <typename ResourceString, typename Finalizer>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  Finalizer finalizeCallback) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             finalizeCallback);
+}
+
+// static
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             finalizeCallback,
+             data);
+}
+
+// static
+template <typename ResourceString, typename ContextType, typename Finalizer>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             context,
+             finalizeCallback);
+}
+
+// static
+template <typename ResourceString,
+          typename ContextType,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             context,
+             finalizeCallback,
+             data);
+}
+
+// static
+template <typename ResourceString>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount) {
+  return New(env,
+             callback,
+             resource,
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             static_cast<void*>(nullptr) /* context */);
+}
+
+// static
+template <typename ResourceString, typename ContextType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context) {
+  return New(env,
+             callback,
+             resource,
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             context,
+             [](Env, ContextType*) {} /* empty finalizer */);
+}
+
+// static
+template <typename ResourceString, typename Finalizer>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  Finalizer finalizeCallback) {
+  return New(env,
+             callback,
+             resource,
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             static_cast<void*>(nullptr) /* context */,
+             finalizeCallback,
+             static_cast<void*>(nullptr) /* data */,
+             details::ThreadSafeFinalize<void, Finalizer>::Wrapper);
+}
+
+// static
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data) {
+  return New(env,
+             callback,
+             resource,
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             static_cast<void*>(nullptr) /* context */,
+             finalizeCallback,
+             data,
+             details::ThreadSafeFinalize<void, Finalizer, FinalizerDataType>::
+                 FinalizeWrapperWithData);
+}
+
+// static
+template <typename ResourceString, typename ContextType, typename Finalizer>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback) {
+  return New(
+      env,
+      callback,
+      resource,
+      resourceName,
+      maxQueueSize,
+      initialThreadCount,
+      context,
+      finalizeCallback,
+      static_cast<void*>(nullptr) /* data */,
+      details::ThreadSafeFinalize<ContextType,
+                                  Finalizer>::FinalizeWrapperWithContext);
+}
+
+// static
+template <typename ResourceString,
+          typename ContextType,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data) {
+  return New(
+      env,
+      callback,
+      resource,
+      resourceName,
+      maxQueueSize,
+      initialThreadCount,
+      context,
+      finalizeCallback,
+      data,
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext);
+}
+
+inline ThreadSafeFunction::ThreadSafeFunction() : _tsfn() {}
+
+inline ThreadSafeFunction::ThreadSafeFunction(napi_threadsafe_function tsfn)
+    : _tsfn(tsfn) {}
+
+inline ThreadSafeFunction::operator napi_threadsafe_function() const {
+  return _tsfn;
+}
+
+inline napi_status ThreadSafeFunction::BlockingCall() const {
+  return CallInternal(nullptr, napi_tsfn_blocking);
+}
+
+template <>
+inline napi_status ThreadSafeFunction::BlockingCall(void* data) const {
+  return napi_call_threadsafe_function(_tsfn, data, napi_tsfn_blocking);
+}
+
+template <typename Callback>
+inline napi_status ThreadSafeFunction::BlockingCall(Callback callback) const {
+  return CallInternal(new CallbackWrapper(callback), napi_tsfn_blocking);
+}
+
+template <typename DataType, typename Callback>
+inline napi_status ThreadSafeFunction::BlockingCall(DataType* data,
+                                                    Callback callback) const {
+  auto wrapper = [data, callback](Env env, Function jsCallback) {
+    callback(env, jsCallback, data);
+  };
+  return CallInternal(new CallbackWrapper(wrapper), napi_tsfn_blocking);
+}
+
+inline napi_status ThreadSafeFunction::NonBlockingCall() const {
+  return CallInternal(nullptr, napi_tsfn_nonblocking);
+}
+
+template <>
+inline napi_status ThreadSafeFunction::NonBlockingCall(void* data) const {
+  return napi_call_threadsafe_function(_tsfn, data, napi_tsfn_nonblocking);
+}
+
+template <typename Callback>
+inline napi_status ThreadSafeFunction::NonBlockingCall(
+    Callback callback) const {
+  return CallInternal(new CallbackWrapper(callback), napi_tsfn_nonblocking);
+}
+
+template <typename DataType, typename Callback>
+inline napi_status ThreadSafeFunction::NonBlockingCall(
+    DataType* data, Callback callback) const {
+  auto wrapper = [data, callback](Env env, Function jsCallback) {
+    callback(env, jsCallback, data);
+  };
+  return CallInternal(new CallbackWrapper(wrapper), napi_tsfn_nonblocking);
+}
+
+inline void ThreadSafeFunction::Ref(napi_env env) const {
+  if (_tsfn != nullptr) {
+    napi_status status = napi_ref_threadsafe_function(env, _tsfn);
+    NAPI_THROW_IF_FAILED_VOID(env, status);
+  }
+}
+
+inline void ThreadSafeFunction::Unref(napi_env env) const {
+  if (_tsfn != nullptr) {
+    napi_status status = napi_unref_threadsafe_function(env, _tsfn);
+    NAPI_THROW_IF_FAILED_VOID(env, status);
+  }
+}
+
+inline napi_status ThreadSafeFunction::Acquire() const {
+  return napi_acquire_threadsafe_function(_tsfn);
+}
+
+inline napi_status ThreadSafeFunction::Release() const {
+  return napi_release_threadsafe_function(_tsfn, napi_tsfn_release);
+}
+
+inline napi_status ThreadSafeFunction::Abort() const {
+  return napi_release_threadsafe_function(_tsfn, napi_tsfn_abort);
+}
+
+inline ThreadSafeFunction::ConvertibleContext ThreadSafeFunction::GetContext()
+    const {
+  void* context;
+  napi_status status = napi_get_threadsafe_function_context(_tsfn, &context);
+  NAPI_FATAL_IF_FAILED(status,
+                       "ThreadSafeFunction::GetContext",
+                       "napi_get_threadsafe_function_context");
+  return ConvertibleContext({context});
+}
+
+// static
+template <typename ResourceString,
+          typename ContextType,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data,
+                                                  napi_finalize wrapper) {
+  static_assert(details::can_make_string<ResourceString>::value ||
+                    std::is_convertible<ResourceString, napi_value>::value,
+                "Resource name should be convertible to the string type");
+
+  ThreadSafeFunction tsfn;
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      callback,
+                                      resource,
+                                      Value::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      finalizeData,
+                                      wrapper,
+                                      context,
+                                      CallJS,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, ThreadSafeFunction());
+  }
+
+  return tsfn;
+}
+
+inline napi_status ThreadSafeFunction::CallInternal(
+    CallbackWrapper* callbackWrapper,
+    napi_threadsafe_function_call_mode mode) const {
+  napi_status status =
+      napi_call_threadsafe_function(_tsfn, callbackWrapper, mode);
+  if (status != napi_ok && callbackWrapper != nullptr) {
+    delete callbackWrapper;
+  }
+
+  return status;
+}
+
+// static
+inline void ThreadSafeFunction::CallJS(napi_env env,
+                                       napi_value jsCallback,
+                                       void* /* context */,
+                                       void* data) {
+  if (env == nullptr && jsCallback == nullptr) {
+    return;
+  }
+
+  details::WrapVoidCallback(env, [&]() {
+    if (data != nullptr) {
+      auto* callbackWrapper = static_cast<CallbackWrapper*>(data);
+      (*callbackWrapper)(env, Function(env, jsCallback));
+      delete callbackWrapper;
+    } else if (jsCallback != nullptr) {
+      Function(env, jsCallback).Call({});
+    }
+  });
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Async Progress Worker Base class
+////////////////////////////////////////////////////////////////////////////////
+template <typename DataType>
+inline AsyncProgressWorkerBase<DataType>::AsyncProgressWorkerBase(
+    const Object& receiver,
+    const Function& callback,
+    const char* resource_name,
+    const Object& resource,
+    size_t queue_size)
+    : AsyncWorker(receiver, callback, resource_name, resource) {
+  // Fill all possible arguments to work around ambiguous
+  // ThreadSafeFunction::New signatures.
+  _tsfn = ThreadSafeFunction::New(callback.Env(),
+                                  callback,
+                                  resource,
+                                  resource_name,
+                                  queue_size,
+                                  /** initialThreadCount */ 1,
+                                  /** context */ this,
+                                  OnThreadSafeFunctionFinalize,
+                                  /** finalizeData */ this);
+}
+
+#if NAPI_VERSION > 4
+template <typename DataType>
+inline AsyncProgressWorkerBase<DataType>::AsyncProgressWorkerBase(
+    Napi::Env env,
+    const char* resource_name,
+    const Object& resource,
+    size_t queue_size)
+    : AsyncWorker(env, resource_name, resource) {
+  // TODO: Once the changes to make the callback optional for threadsafe
+  // functions are available on all versions we can remove the dummy Function
+  // here.
+  Function callback;
+  // Fill all possible arguments to work around ambiguous
+  // ThreadSafeFunction::New signatures.
+  _tsfn = ThreadSafeFunction::New(env,
+                                  callback,
+                                  resource,
+                                  resource_name,
+                                  queue_size,
+                                  /** initialThreadCount */ 1,
+                                  /** context */ this,
+                                  OnThreadSafeFunctionFinalize,
+                                  /** finalizeData */ this);
+}
+#endif
+
+template <typename DataType>
+inline AsyncProgressWorkerBase<DataType>::~AsyncProgressWorkerBase() {
+  // Abort pending tsfn call.
+  // Don't send progress events after we've already completed.
+  // It's ok to call ThreadSafeFunction::Abort and ThreadSafeFunction::Release
+  // duplicated.
+  _tsfn.Abort();
+}
+
+template <typename DataType>
+inline void AsyncProgressWorkerBase<DataType>::OnAsyncWorkProgress(
+    Napi::Env /* env */, Napi::Function /* jsCallback */, void* data) {
+  ThreadSafeData* tsd = static_cast<ThreadSafeData*>(data);
+  tsd->asyncprogressworker()->OnWorkProgress(tsd->data());
+  delete tsd;
+}
+
+template <typename DataType>
+inline napi_status AsyncProgressWorkerBase<DataType>::NonBlockingCall(
+    DataType* data) {
+  auto tsd = new AsyncProgressWorkerBase::ThreadSafeData(this, data);
+  auto ret = _tsfn.NonBlockingCall(tsd, OnAsyncWorkProgress);
+  if (ret != napi_ok) {
+    delete tsd;
+  }
+  return ret;
+}
+
+template <typename DataType>
+inline void AsyncProgressWorkerBase<DataType>::OnWorkComplete(
+    Napi::Env /* env */, napi_status status) {
+  _work_completed = true;
+  _complete_status = status;
+  _tsfn.Release();
+}
+
+template <typename DataType>
+inline void AsyncProgressWorkerBase<DataType>::OnThreadSafeFunctionFinalize(
+    Napi::Env env, void* /* data */, AsyncProgressWorkerBase* context) {
+  if (context->_work_completed) {
+    context->AsyncWorker::OnWorkComplete(env, context->_complete_status);
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Async Progress Worker class
+////////////////////////////////////////////////////////////////////////////////
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Function& callback)
+    : AsyncProgressWorker(callback, "generic") {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Function& callback,
+                                                   const char* resource_name)
+    : AsyncProgressWorker(
+          callback, resource_name, Object::New(callback.Env())) {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Function& callback,
+                                                   const char* resource_name,
+                                                   const Object& resource)
+    : AsyncProgressWorker(
+          Object::New(callback.Env()), callback, resource_name, resource) {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Object& receiver,
+                                                   const Function& callback)
+    : AsyncProgressWorker(receiver, callback, "generic") {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Object& receiver,
+                                                   const Function& callback,
+                                                   const char* resource_name)
+    : AsyncProgressWorker(
+          receiver, callback, resource_name, Object::New(callback.Env())) {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Object& receiver,
+                                                   const Function& callback,
+                                                   const char* resource_name,
+                                                   const Object& resource)
+    : AsyncProgressWorkerBase(receiver, callback, resource_name, resource),
+      _asyncdata(nullptr),
+      _asyncsize(0),
+      _signaled(false) {}
+
+#if NAPI_VERSION > 4
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(Napi::Env env)
+    : AsyncProgressWorker(env, "generic") {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(Napi::Env env,
+                                                   const char* resource_name)
+    : AsyncProgressWorker(env, resource_name, Object::New(env)) {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(Napi::Env env,
+                                                   const char* resource_name,
+                                                   const Object& resource)
+    : AsyncProgressWorkerBase(env, resource_name, resource),
+      _asyncdata(nullptr),
+      _asyncsize(0) {}
+#endif
+
+template <class T>
+inline AsyncProgressWorker<T>::~AsyncProgressWorker() {
+  {
+    std::lock_guard<std::mutex> lock(this->_mutex);
+    _asyncdata = nullptr;
+    _asyncsize = 0;
+  }
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::Execute() {
+  ExecutionProgress progress(this);
+  Execute(progress);
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::OnWorkProgress(void*) {
+  T* data;
+  size_t size;
+  bool signaled;
+  {
+    std::lock_guard<std::mutex> lock(this->_mutex);
+    data = this->_asyncdata;
+    size = this->_asyncsize;
+    signaled = this->_signaled;
+    this->_asyncdata = nullptr;
+    this->_asyncsize = 0;
+    this->_signaled = false;
+  }
+
+  /**
+   * The callback of ThreadSafeFunction is not been invoked immediately on the
+   * callback of uv_async_t (uv io poll), rather the callback of TSFN is
+   * invoked on the right next uv idle callback. There are chances that during
+   * the deferring the signal of uv_async_t is been sent again, i.e. potential
+   * not coalesced two calls of the TSFN callback.
+   */
+  if (data == nullptr && !signaled) {
+    return;
+  }
+
+  this->OnProgress(data, size);
+  delete[] data;
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::SendProgress_(const T* data, size_t count) {
+  T* new_data = new T[count];
+  std::copy(data, data + count, new_data);
+
+  T* old_data;
+  {
+    std::lock_guard<std::mutex> lock(this->_mutex);
+    old_data = _asyncdata;
+    _asyncdata = new_data;
+    _asyncsize = count;
+    _signaled = false;
+  }
+  this->NonBlockingCall(nullptr);
+
+  delete[] old_data;
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::Signal() {
+  {
+    std::lock_guard<std::mutex> lock(this->_mutex);
+    _signaled = true;
+  }
+  this->NonBlockingCall(static_cast<T*>(nullptr));
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::ExecutionProgress::Signal() const {
+  this->_worker->Signal();
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::ExecutionProgress::Send(
+    const T* data, size_t count) const {
+  _worker->SendProgress_(data, count);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Async Progress Queue Worker class
+////////////////////////////////////////////////////////////////////////////////
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Function& callback)
+    : AsyncProgressQueueWorker(callback, "generic") {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Function& callback, const char* resource_name)
+    : AsyncProgressQueueWorker(
+          callback, resource_name, Object::New(callback.Env())) {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Function& callback, const char* resource_name, const Object& resource)
+    : AsyncProgressQueueWorker(
+          Object::New(callback.Env()), callback, resource_name, resource) {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Object& receiver, const Function& callback)
+    : AsyncProgressQueueWorker(receiver, callback, "generic") {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Object& receiver, const Function& callback, const char* resource_name)
+    : AsyncProgressQueueWorker(
+          receiver, callback, resource_name, Object::New(callback.Env())) {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Object& receiver,
+    const Function& callback,
+    const char* resource_name,
+    const Object& resource)
+    : AsyncProgressWorkerBase<std::pair<T*, size_t>>(
+          receiver,
+          callback,
+          resource_name,
+          resource,
+          /** unlimited queue size */ 0) {}
+
+#if NAPI_VERSION > 4
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(Napi::Env env)
+    : AsyncProgressQueueWorker(env, "generic") {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    Napi::Env env, const char* resource_name)
+    : AsyncProgressQueueWorker(env, resource_name, Object::New(env)) {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    Napi::Env env, const char* resource_name, const Object& resource)
+    : AsyncProgressWorkerBase<std::pair<T*, size_t>>(
+          env, resource_name, resource, /** unlimited queue size */ 0) {}
+#endif
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::Execute() {
+  ExecutionProgress progress(this);
+  Execute(progress);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::OnWorkProgress(
+    std::pair<T*, size_t>* datapair) {
+  if (datapair == nullptr) {
+    return;
+  }
+
+  T* data = datapair->first;
+  size_t size = datapair->second;
+
+  this->OnProgress(data, size);
+  delete datapair;
+  delete[] data;
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::SendProgress_(const T* data,
+                                                       size_t count) {
+  T* new_data = new T[count];
+  std::copy(data, data + count, new_data);
+
+  auto pair = new std::pair<T*, size_t>(new_data, count);
+  this->NonBlockingCall(pair);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::Signal() const {
+  this->SendProgress_(static_cast<T*>(nullptr), 0);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::OnWorkComplete(Napi::Env env,
+                                                        napi_status status) {
+  // Draining queued items in TSFN.
+  AsyncProgressWorkerBase<std::pair<T*, size_t>>::OnWorkComplete(env, status);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::ExecutionProgress::Signal() const {
+  _worker->SendProgress_(static_cast<T*>(nullptr), 0);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::ExecutionProgress::Send(
+    const T* data, size_t count) const {
+  _worker->SendProgress_(data, count);
+}
+#endif  // NAPI_VERSION > 3 && NAPI_HAS_THREADS
+
+////////////////////////////////////////////////////////////////////////////////
+// Memory Management class
+////////////////////////////////////////////////////////////////////////////////
+
+inline int64_t MemoryManagement::AdjustExternalMemory(BasicEnv env,
+                                                      int64_t change_in_bytes) {
+  int64_t result;
+  napi_status status =
+      napi_adjust_external_memory(env, change_in_bytes, &result);
+  NAPI_FATAL_IF_FAILED(status,
+                       "MemoryManagement::AdjustExternalMemory",
+                       "napi_adjust_external_memory");
+  return result;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Version Management class
+////////////////////////////////////////////////////////////////////////////////
+
+inline uint32_t VersionManagement::GetNapiVersion(BasicEnv env) {
+  uint32_t result;
+  napi_status status = napi_get_version(env, &result);
+  NAPI_FATAL_IF_FAILED(
+      status, "VersionManagement::GetNapiVersion", "napi_get_version");
+  return result;
+}
+
+inline const napi_node_version* VersionManagement::GetNodeVersion(
+    BasicEnv env) {
+  const napi_node_version* result;
+  napi_status status = napi_get_node_version(env, &result);
+  NAPI_FATAL_IF_FAILED(
+      status, "VersionManagement::GetNodeVersion", "napi_get_node_version");
+  return result;
+}
+
+#if NAPI_VERSION > 5
+////////////////////////////////////////////////////////////////////////////////
+// Addon<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline Object Addon<T>::Init(Env env, Object exports) {
+  T* addon = new T(env, exports);
+  env.SetInstanceData(addon);
+  return addon->entry_point_;
+}
+
+template <typename T>
+inline T* Addon<T>::Unwrap(Object wrapper) {
+  return wrapper.Env().GetInstanceData<T>();
+}
+
+template <typename T>
+inline void Addon<T>::DefineAddon(
+    Object exports, const std::initializer_list<AddonProp>& props) {
+  DefineProperties(exports, props);
+  entry_point_ = exports;
+}
+
+template <typename T>
+inline Napi::Object Addon<T>::DefineProperties(
+    Object object, const std::initializer_list<AddonProp>& props) {
+  const napi_property_descriptor* properties =
+      reinterpret_cast<const napi_property_descriptor*>(props.begin());
+  size_t size = props.size();
+  napi_status status =
+      napi_define_properties(object.Env(), object, size, properties);
+  NAPI_THROW_IF_FAILED(object.Env(), status, object);
+  for (size_t idx = 0; idx < size; idx++)
+    T::AttachPropData(object.Env(), object, &properties[idx]);
+  return object;
+}
+#endif  // NAPI_VERSION > 5
+
+#if NAPI_VERSION > 2
+template <typename Hook, typename Arg>
+Env::CleanupHook<Hook, Arg> BasicEnv::AddCleanupHook(Hook hook, Arg* arg) {
+  return CleanupHook<Hook, Arg>(*this, hook, arg);
+}
+
+template <typename Hook>
+Env::CleanupHook<Hook> BasicEnv::AddCleanupHook(Hook hook) {
+  return CleanupHook<Hook>(*this, hook);
+}
+
+template <typename Hook, typename Arg>
+Env::CleanupHook<Hook, Arg>::CleanupHook() {
+  data = nullptr;
+}
+
+template <typename Hook, typename Arg>
+Env::CleanupHook<Hook, Arg>::CleanupHook(Napi::BasicEnv env, Hook hook)
+    : wrapper(Env::CleanupHook<Hook, Arg>::Wrapper) {
+  data = new CleanupData{std::move(hook), nullptr};
+  napi_status status = napi_add_env_cleanup_hook(env, wrapper, data);
+  if (status != napi_ok) {
+    delete data;
+    data = nullptr;
+  }
+}
+
+template <typename Hook, typename Arg>
+Env::CleanupHook<Hook, Arg>::CleanupHook(Napi::BasicEnv env,
+                                         Hook hook,
+                                         Arg* arg)
+    : wrapper(Env::CleanupHook<Hook, Arg>::WrapperWithArg) {
+  data = new CleanupData{std::move(hook), arg};
+  napi_status status = napi_add_env_cleanup_hook(env, wrapper, data);
+  if (status != napi_ok) {
+    delete data;
+    data = nullptr;
+  }
+}
+
+template <class Hook, class Arg>
+bool Env::CleanupHook<Hook, Arg>::Remove(BasicEnv env) {
+  napi_status status = napi_remove_env_cleanup_hook(env, wrapper, data);
+  delete data;
+  data = nullptr;
+  return status == napi_ok;
+}
+
+template <class Hook, class Arg>
+bool Env::CleanupHook<Hook, Arg>::IsEmpty() const {
+  return data == nullptr;
+}
+#endif  // NAPI_VERSION > 2
+
+#ifdef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+template <typename FinalizerType>
+inline void BasicEnv::PostFinalizer(FinalizerType finalizeCallback) const {
+  using T = void*;
+  details::FinalizeData<T, FinalizerType>* finalizeData =
+      new details::FinalizeData<T, FinalizerType>(
+          {std::move(finalizeCallback), nullptr});
+
+  napi_status status = node_api_post_finalizer(
+      _env,
+      details::FinalizeData<T, FinalizerType>::WrapperGCWithoutData,
+      static_cast<void*>(nullptr),
+      finalizeData);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_FATAL_IF_FAILED(
+        status, "BasicEnv::PostFinalizer", "invalid arguments");
+  }
+}
+
+template <typename FinalizerType, typename T>
+inline void BasicEnv::PostFinalizer(FinalizerType finalizeCallback,
+                                    T* data) const {
+  details::FinalizeData<T, FinalizerType>* finalizeData =
+      new details::FinalizeData<T, FinalizerType>(
+          {std::move(finalizeCallback), nullptr});
+
+  napi_status status = node_api_post_finalizer(
+      _env,
+      details::FinalizeData<T, FinalizerType>::WrapperGC,
+      data,
+      finalizeData);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_FATAL_IF_FAILED(
+        status, "BasicEnv::PostFinalizer", "invalid arguments");
+  }
+}
+
+template <typename FinalizerType, typename T, typename Hint>
+inline void BasicEnv::PostFinalizer(FinalizerType finalizeCallback,
+                                    T* data,
+                                    Hint* finalizeHint) const {
+  details::FinalizeData<T, FinalizerType, Hint>* finalizeData =
+      new details::FinalizeData<T, FinalizerType, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+  napi_status status = node_api_post_finalizer(
+      _env,
+      details::FinalizeData<T, FinalizerType, Hint>::WrapperGCWithHint,
+      data,
+      finalizeData);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_FATAL_IF_FAILED(
+        status, "BasicEnv::PostFinalizer", "invalid arguments");
+  }
+}
+#endif  // NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+
+#ifdef NAPI_CPP_CUSTOM_NAMESPACE
+}  // namespace NAPI_CPP_CUSTOM_NAMESPACE
+#endif
+
+}  // namespace Napi
+
+#endif  // SRC_NAPI_INL_H_
diff --git a/server/node_modules/node-addon-api/napi.h b/server/node_modules/node-addon-api/napi.h
new file mode 100644
index 0000000..ba0e134
--- /dev/null
+++ b/server/node_modules/node-addon-api/napi.h
@@ -0,0 +1,3309 @@
+#ifndef SRC_NAPI_H_
+#define SRC_NAPI_H_
+
+#ifndef NAPI_HAS_THREADS
+#if !defined(__wasm__) || (defined(__EMSCRIPTEN_PTHREADS__) ||                 \
+                           (defined(__wasi__) && defined(_REENTRANT)))
+#define NAPI_HAS_THREADS 1
+#else
+#define NAPI_HAS_THREADS 0
+#endif
+#endif
+
+#include <node_api.h>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#if NAPI_HAS_THREADS
+#include <mutex>
+#endif  // NAPI_HAS_THREADS
+#include <string>
+#include <vector>
+
+// VS2015 RTM has bugs with constexpr, so require min of VS2015 Update 3 (known
+// good version)
+#if !defined(_MSC_VER) || _MSC_FULL_VER >= 190024210
+#define NAPI_HAS_CONSTEXPR 1
+#endif
+
+// VS2013 does not support char16_t literal strings, so we'll work around it
+// using wchar_t strings and casting them. This is safe as long as the character
+// sizes are the same.
+#if defined(_MSC_VER) && _MSC_VER <= 1800
+static_assert(sizeof(char16_t) == sizeof(wchar_t),
+              "Size mismatch between char16_t and wchar_t");
+#define NAPI_WIDE_TEXT(x) reinterpret_cast<char16_t*>(L##x)
+#else
+#define NAPI_WIDE_TEXT(x) u##x
+#endif
+
+// Backwards-compatibility to handle the rename of this macro definition, in
+// case they are used within userland code.
+#ifdef NAPI_CPP_EXCEPTIONS
+#define NODE_ADDON_API_CPP_EXCEPTIONS
+#endif
+#if defined(NODE_ADDON_API_CPP_EXCEPTIONS) && !defined(NAPI_CPP_EXCEPTIONS)
+#define NAPI_CPP_EXCEPTIONS
+#endif
+#ifdef NAPI_DISABLE_CPP_EXCEPTIONS
+#define NODE_ADDON_API_DISABLE_CPP_EXCEPTIONS
+#endif
+#if defined(NODE_ADDON_API_DISABLE_CPP_EXCEPTIONS) &&                          \
+    !defined(NAPI_DISABLE_CPP_EXCEPTIONS)
+#define NAPI_DISABLE_CPP_EXCEPTIONS
+#endif
+
+// If C++ exceptions are not explicitly enabled or disabled, enable them
+// if exceptions were enabled in the compiler settings.
+#if !defined(NODE_ADDON_API_CPP_EXCEPTIONS) &&                                 \
+    !defined(NODE_ADDON_API_DISABLE_CPP_EXCEPTIONS)
+#if defined(_CPPUNWIND) || defined(__EXCEPTIONS)
+#define NODE_ADDON_API_CPP_EXCEPTIONS
+#else
+#error Exception support not detected. \
+      Define either NODE_ADDON_API_CPP_EXCEPTIONS or NODE_ADDON_API_DISABLE_CPP_EXCEPTIONS.
+#endif
+#endif
+
+// If C++ NODE_ADDON_API_CPP_EXCEPTIONS are enabled, NODE_ADDON_API_ENABLE_MAYBE
+// should not be set
+#if defined(NODE_ADDON_API_CPP_EXCEPTIONS) &&                                  \
+    defined(NODE_ADDON_API_ENABLE_MAYBE)
+#error NODE_ADDON_API_ENABLE_MAYBE should not be set when \
+    NODE_ADDON_API_CPP_EXCEPTIONS is defined.
+#endif
+
+#ifdef _NOEXCEPT
+#define NAPI_NOEXCEPT _NOEXCEPT
+#else
+#define NAPI_NOEXCEPT noexcept
+#endif
+
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+
+// When C++ exceptions are enabled, Errors are thrown directly. There is no need
+// to return anything after the throw statements. The variadic parameter is an
+// optional return value that is ignored.
+// We need _VOID versions of the macros to avoid warnings resulting from
+// leaving the NAPI_THROW_* `...` argument empty.
+
+#define NAPI_THROW(e, ...) throw e
+#define NAPI_THROW_VOID(e) throw e
+
+#define NAPI_THROW_IF_FAILED(env, status, ...)                                 \
+  if ((status) != napi_ok) throw Napi::Error::New(env);
+
+#define NAPI_THROW_IF_FAILED_VOID(env, status)                                 \
+  if ((status) != napi_ok) throw Napi::Error::New(env);
+
+#else  // NODE_ADDON_API_CPP_EXCEPTIONS
+
+// When C++ exceptions are disabled, Errors are thrown as JavaScript exceptions,
+// which are pending until the callback returns to JS.  The variadic parameter
+// is an optional return value; usually it is an empty result.
+// We need _VOID versions of the macros to avoid warnings resulting from
+// leaving the NAPI_THROW_* `...` argument empty.
+
+#define NAPI_THROW(e, ...)                                                     \
+  do {                                                                         \
+    (e).ThrowAsJavaScriptException();                                          \
+    return __VA_ARGS__;                                                        \
+  } while (0)
+
+#define NAPI_THROW_VOID(e)                                                     \
+  do {                                                                         \
+    (e).ThrowAsJavaScriptException();                                          \
+    return;                                                                    \
+  } while (0)
+
+#define NAPI_THROW_IF_FAILED(env, status, ...)                                 \
+  if ((status) != napi_ok) {                                                   \
+    Napi::Error::New(env).ThrowAsJavaScriptException();                        \
+    return __VA_ARGS__;                                                        \
+  }
+
+#define NAPI_THROW_IF_FAILED_VOID(env, status)                                 \
+  if ((status) != napi_ok) {                                                   \
+    Napi::Error::New(env).ThrowAsJavaScriptException();                        \
+    return;                                                                    \
+  }
+
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+#define NAPI_MAYBE_THROW_IF_FAILED(env, status, type)                          \
+  NAPI_THROW_IF_FAILED(env, status, Napi::Nothing<type>())
+
+#define NAPI_RETURN_OR_THROW_IF_FAILED(env, status, result, type)              \
+  NAPI_MAYBE_THROW_IF_FAILED(env, status, type);                               \
+  return Napi::Just<type>(result);
+#else
+#define NAPI_MAYBE_THROW_IF_FAILED(env, status, type)                          \
+  NAPI_THROW_IF_FAILED(env, status, type())
+
+#define NAPI_RETURN_OR_THROW_IF_FAILED(env, status, result, type)              \
+  NAPI_MAYBE_THROW_IF_FAILED(env, status, type);                               \
+  return result;
+#endif
+
+#define NAPI_DISALLOW_ASSIGN(CLASS) void operator=(const CLASS&) = delete;
+#define NAPI_DISALLOW_COPY(CLASS) CLASS(const CLASS&) = delete;
+
+#define NAPI_DISALLOW_ASSIGN_COPY(CLASS)                                       \
+  NAPI_DISALLOW_ASSIGN(CLASS)                                                  \
+  NAPI_DISALLOW_COPY(CLASS)
+
+#define NAPI_CHECK(condition, location, message)                               \
+  do {                                                                         \
+    if (!(condition)) {                                                        \
+      Napi::Error::Fatal((location), (message));                               \
+    }                                                                          \
+  } while (0)
+
+// Internal check helper. Be careful that the formatted message length should be
+// max 255 size and null terminated.
+#define NAPI_INTERNAL_CHECK(expr, location, ...)                               \
+  do {                                                                         \
+    if (!(expr)) {                                                             \
+      std::string msg = Napi::details::StringFormat(__VA_ARGS__);              \
+      Napi::Error::Fatal(location, msg.c_str());                               \
+    }                                                                          \
+  } while (0)
+
+#define NAPI_INTERNAL_CHECK_EQ(actual, expected, value_format, location)       \
+  do {                                                                         \
+    auto actual_value = (actual);                                              \
+    NAPI_INTERNAL_CHECK(actual_value == (expected),                            \
+                        location,                                              \
+                        "Expected " #actual " to be equal to " #expected       \
+                        ", but got " value_format ".",                         \
+                        actual_value);                                         \
+  } while (0)
+
+#define NAPI_FATAL_IF_FAILED(status, location, message)                        \
+  NAPI_CHECK((status) == napi_ok, location, message)
+
+////////////////////////////////////////////////////////////////////////////////
+/// Node-API C++ Wrapper Classes
+///
+/// These classes wrap the "Node-API" ABI-stable C APIs for Node.js, providing a
+/// C++ object model and C++ exception-handling semantics with low overhead.
+/// The wrappers are all header-only so that they do not affect the ABI.
+////////////////////////////////////////////////////////////////////////////////
+namespace Napi {
+
+#ifdef NAPI_CPP_CUSTOM_NAMESPACE
+// NAPI_CPP_CUSTOM_NAMESPACE can be #define'd per-addon to avoid symbol
+// conflicts between different instances of node-addon-api
+
+// First dummy definition of the namespace to make sure that Napi::(name) still
+// refers to the right things inside this file.
+namespace NAPI_CPP_CUSTOM_NAMESPACE {}
+using namespace NAPI_CPP_CUSTOM_NAMESPACE;
+
+namespace NAPI_CPP_CUSTOM_NAMESPACE {
+#endif
+
+// Forward declarations
+class Env;
+class Value;
+class Boolean;
+class Number;
+#if NAPI_VERSION > 5
+class BigInt;
+#endif  // NAPI_VERSION > 5
+#if (NAPI_VERSION > 4)
+class Date;
+#endif
+class String;
+class Object;
+class Array;
+class ArrayBuffer;
+class Function;
+class Error;
+class PropertyDescriptor;
+class CallbackInfo;
+class TypedArray;
+template <typename T>
+class TypedArrayOf;
+
+using Int8Array =
+    TypedArrayOf<int8_t>;  ///< Typed-array of signed 8-bit integers
+using Uint8Array =
+    TypedArrayOf<uint8_t>;  ///< Typed-array of unsigned 8-bit integers
+using Int16Array =
+    TypedArrayOf<int16_t>;  ///< Typed-array of signed 16-bit integers
+using Uint16Array =
+    TypedArrayOf<uint16_t>;  ///< Typed-array of unsigned 16-bit integers
+using Int32Array =
+    TypedArrayOf<int32_t>;  ///< Typed-array of signed 32-bit integers
+using Uint32Array =
+    TypedArrayOf<uint32_t>;  ///< Typed-array of unsigned 32-bit integers
+using Float32Array =
+    TypedArrayOf<float>;  ///< Typed-array of 32-bit floating-point values
+using Float64Array =
+    TypedArrayOf<double>;  ///< Typed-array of 64-bit floating-point values
+#if NAPI_VERSION > 5
+using BigInt64Array =
+    TypedArrayOf<int64_t>;  ///< Typed array of signed 64-bit integers
+using BigUint64Array =
+    TypedArrayOf<uint64_t>;  ///< Typed array of unsigned 64-bit integers
+#endif                       // NAPI_VERSION > 5
+
+/// Defines the signature of a Node-API C++ module's registration callback
+/// (init) function.
+using ModuleRegisterCallback = Object (*)(Env env, Object exports);
+
+class MemoryManagement;
+
+/// A simple Maybe type, representing an object which may or may not have a
+/// value.
+///
+/// If an API method returns a Maybe<>, the API method can potentially fail
+/// either because an exception is thrown, or because an exception is pending,
+/// e.g. because a previous API call threw an exception that hasn't been
+/// caught yet. In that case, a "Nothing" value is returned.
+template <class T>
+class Maybe {
+ public:
+  bool IsNothing() const;
+  bool IsJust() const;
+
+  /// Short-hand for Unwrap(), which doesn't return a value. Could be used
+  /// where the actual value of the Maybe is not needed like Object::Set.
+  /// If this Maybe is nothing (empty), node-addon-api will crash the
+  /// process.
+  void Check() const;
+
+  /// Return the value of type T contained in the Maybe. If this Maybe is
+  /// nothing (empty), node-addon-api will crash the process.
+  T Unwrap() const;
+
+  /// Return the value of type T contained in the Maybe, or using a default
+  /// value if this Maybe is nothing (empty).
+  T UnwrapOr(const T& default_value) const;
+
+  /// Converts this Maybe to a value of type T in the out. If this Maybe is
+  /// nothing (empty), `false` is returned and `out` is left untouched.
+  bool UnwrapTo(T* out) const;
+
+  bool operator==(const Maybe& other) const;
+  bool operator!=(const Maybe& other) const;
+
+ private:
+  Maybe();
+  explicit Maybe(const T& t);
+
+  bool _has_value;
+  T _value;
+
+  template <class U>
+  friend Maybe<U> Nothing();
+  template <class U>
+  friend Maybe<U> Just(const U& u);
+};
+
+template <class T>
+inline Maybe<T> Nothing();
+
+template <class T>
+inline Maybe<T> Just(const T& t);
+
+#if defined(NODE_ADDON_API_ENABLE_MAYBE)
+template <typename T>
+using MaybeOrValue = Maybe<T>;
+#else
+template <typename T>
+using MaybeOrValue = T;
+#endif
+
+#ifdef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+using node_addon_api_basic_env = node_api_nogc_env;
+using node_addon_api_basic_finalize = node_api_nogc_finalize;
+#else
+using node_addon_api_basic_env = napi_env;
+using node_addon_api_basic_finalize = napi_finalize;
+#endif
+
+/// Environment for Node-API values and operations.
+///
+/// All Node-API values and operations must be associated with an environment.
+/// An environment instance is always provided to callback functions; that
+/// environment must then be used for any creation of Node-API values or other
+/// Node-API operations within the callback. (Many methods infer the
+/// environment from the `this` instance that the method is called on.)
+///
+/// Multiple environments may co-exist in a single process or a thread.
+///
+/// In the V8 JavaScript engine, a Node-API environment approximately
+/// corresponds to an Isolate.
+class BasicEnv {
+ private:
+  node_addon_api_basic_env _env;
+#if NAPI_VERSION > 5
+  template <typename T>
+  static void DefaultFini(Env, T* data);
+  template <typename DataType, typename HintType>
+  static void DefaultFiniWithHint(Env, DataType* data, HintType* hint);
+#endif  // NAPI_VERSION > 5
+ public:
+  BasicEnv(node_addon_api_basic_env env);
+
+  operator node_addon_api_basic_env() const;
+
+  // Without these operator overloads, the error:
+  //
+  //    Use of overloaded operator '==' is ambiguous (with operand types
+  //    'Napi::Env' and 'Napi::Env')
+  //
+  // ... occurs when comparing foo.Env() == bar.Env() or foo.Env() == nullptr
+  bool operator==(const BasicEnv& other) const {
+    return _env == other._env;
+  };
+  bool operator==(std::nullptr_t /*other*/) const {
+    return _env == nullptr;
+  };
+
+#if NAPI_VERSION > 2
+  template <typename Hook, typename Arg = void>
+  class CleanupHook;
+
+  template <typename Hook>
+  CleanupHook<Hook> AddCleanupHook(Hook hook);
+
+  template <typename Hook, typename Arg>
+  CleanupHook<Hook, Arg> AddCleanupHook(Hook hook, Arg* arg);
+#endif  // NAPI_VERSION > 2
+
+#if NAPI_VERSION > 5
+  template <typename T>
+  T* GetInstanceData() const;
+
+  template <typename T>
+  using Finalizer = void (*)(Env, T*);
+  template <typename T, Finalizer<T> fini = BasicEnv::DefaultFini<T>>
+  void SetInstanceData(T* data) const;
+
+  template <typename DataType, typename HintType>
+  using FinalizerWithHint = void (*)(Env, DataType*, HintType*);
+  template <typename DataType,
+            typename HintType,
+            FinalizerWithHint<DataType, HintType> fini =
+                BasicEnv::DefaultFiniWithHint<DataType, HintType>>
+  void SetInstanceData(DataType* data, HintType* hint) const;
+#endif  // NAPI_VERSION > 5
+
+#if NAPI_VERSION > 2
+  template <typename Hook, typename Arg>
+  class CleanupHook {
+   public:
+    CleanupHook();
+    CleanupHook(BasicEnv env, Hook hook, Arg* arg);
+    CleanupHook(BasicEnv env, Hook hook);
+    bool Remove(BasicEnv env);
+    bool IsEmpty() const;
+
+   private:
+    static inline void Wrapper(void* data) NAPI_NOEXCEPT;
+    static inline void WrapperWithArg(void* data) NAPI_NOEXCEPT;
+
+    void (*wrapper)(void* arg);
+    struct CleanupData {
+      Hook hook;
+      Arg* arg;
+    } * data;
+  };
+#endif  // NAPI_VERSION > 2
+
+#if NAPI_VERSION > 8
+  const char* GetModuleFileName() const;
+#endif  // NAPI_VERSION > 8
+
+#ifdef NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+  template <typename FinalizerType>
+  inline void PostFinalizer(FinalizerType finalizeCallback) const;
+
+  template <typename FinalizerType, typename T>
+  inline void PostFinalizer(FinalizerType finalizeCallback, T* data) const;
+
+  template <typename FinalizerType, typename T, typename Hint>
+  inline void PostFinalizer(FinalizerType finalizeCallback,
+                            T* data,
+                            Hint* finalizeHint) const;
+#endif  // NODE_API_EXPERIMENTAL_HAS_POST_FINALIZER
+
+  friend class Env;
+};
+
+class Env : public BasicEnv {
+ public:
+  Env(napi_env env);
+
+  operator napi_env() const;
+
+  Object Global() const;
+  Value Undefined() const;
+  Value Null() const;
+
+  bool IsExceptionPending() const;
+  Error GetAndClearPendingException() const;
+
+  MaybeOrValue<Value> RunScript(const char* utf8script) const;
+  MaybeOrValue<Value> RunScript(const std::string& utf8script) const;
+  MaybeOrValue<Value> RunScript(String script) const;
+};
+
+/// A JavaScript value of unknown type.
+///
+/// For type-specific operations, convert to one of the Value subclasses using a
+/// `To*` or `As()` method. The `To*` methods do type coercion; the `As()`
+/// method does not.
+///
+///     Napi::Value value = ...
+///     if (!value.IsString()) throw Napi::TypeError::New(env, "Invalid
+///     arg..."); Napi::String str = value.As<Napi::String>(); // Cast to a
+///     string value
+///
+///     Napi::Value anotherValue = ...
+///     bool isTruthy = anotherValue.ToBoolean(); // Coerce to a boolean value
+class Value {
+ public:
+  Value();  ///< Creates a new _empty_ Value instance.
+  Value(napi_env env,
+        napi_value value);  ///< Wraps a Node-API value primitive.
+
+  /// Creates a JS value from a C++ primitive.
+  ///
+  /// `value` may be any of:
+  /// - bool
+  /// - Any integer type
+  /// - Any floating point type
+  /// - const char* (encoded using UTF-8, null-terminated)
+  /// - const char16_t* (encoded using UTF-16-LE, null-terminated)
+  /// - std::string (encoded using UTF-8)
+  /// - std::u16string
+  /// - napi::Value
+  /// - napi_value
+  template <typename T>
+  static Value From(napi_env env, const T& value);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  /// Converts to a Node-API value primitive.
+  ///
+  /// If the instance is _empty_, this returns `nullptr`.
+  operator napi_value() const;
+
+  /// Tests if this value strictly equals another value.
+  bool operator==(const Value& other) const;
+
+  /// Tests if this value does not strictly equal another value.
+  bool operator!=(const Value& other) const;
+
+  /// Tests if this value strictly equals another value.
+  bool StrictEquals(const Value& other) const;
+
+  /// Gets the environment the value is associated with.
+  Napi::Env Env() const;
+
+  /// Checks if the value is empty (uninitialized).
+  ///
+  /// An empty value is invalid, and most attempts to perform an operation on an
+  /// empty value will result in an exception. Note an empty value is distinct
+  /// from JavaScript `null` or `undefined`, which are valid values.
+  ///
+  /// When C++ exceptions are disabled at compile time, a method with a `Value`
+  /// return type may return an empty value to indicate a pending exception. So
+  /// when not using C++ exceptions, callers should check whether the value is
+  /// empty before attempting to use it.
+  bool IsEmpty() const;
+
+  napi_valuetype Type() const;  ///< Gets the type of the value.
+
+  bool IsUndefined()
+      const;            ///< Tests if a value is an undefined JavaScript value.
+  bool IsNull() const;  ///< Tests if a value is a null JavaScript value.
+  bool IsBoolean() const;  ///< Tests if a value is a JavaScript boolean.
+  bool IsNumber() const;   ///< Tests if a value is a JavaScript number.
+#if NAPI_VERSION > 5
+  bool IsBigInt() const;  ///< Tests if a value is a JavaScript bigint.
+#endif                    // NAPI_VERSION > 5
+#if (NAPI_VERSION > 4)
+  bool IsDate() const;  ///< Tests if a value is a JavaScript date.
+#endif
+  bool IsString() const;  ///< Tests if a value is a JavaScript string.
+  bool IsSymbol() const;  ///< Tests if a value is a JavaScript symbol.
+  bool IsArray() const;   ///< Tests if a value is a JavaScript array.
+  bool IsArrayBuffer()
+      const;  ///< Tests if a value is a JavaScript array buffer.
+  bool IsTypedArray() const;  ///< Tests if a value is a JavaScript typed array.
+  bool IsObject() const;      ///< Tests if a value is a JavaScript object.
+  bool IsFunction() const;    ///< Tests if a value is a JavaScript function.
+  bool IsPromise() const;     ///< Tests if a value is a JavaScript promise.
+  bool IsDataView() const;    ///< Tests if a value is a JavaScript data view.
+  bool IsBuffer() const;      ///< Tests if a value is a Node buffer.
+  bool IsExternal() const;  ///< Tests if a value is a pointer to external data.
+
+  /// Casts to another type of `Napi::Value`, when the actual type is known or
+  /// assumed.
+  ///
+  /// This conversion does NOT coerce the type. Calling any methods
+  /// inappropriate for the actual value type will throw `Napi::Error`.
+  ///
+  /// If `NODE_ADDON_API_ENABLE_TYPE_CHECK_ON_AS` is defined, this method
+  /// asserts that the actual type is the expected type.
+  template <typename T>
+  T As() const;
+
+  // Unsafe Value::As(), should be avoided.
+  template <typename T>
+  T UnsafeAs() const;
+
+  MaybeOrValue<Boolean> ToBoolean()
+      const;  ///< Coerces a value to a JavaScript boolean.
+  MaybeOrValue<Number> ToNumber()
+      const;  ///< Coerces a value to a JavaScript number.
+  MaybeOrValue<String> ToString()
+      const;  ///< Coerces a value to a JavaScript string.
+  MaybeOrValue<Object> ToObject()
+      const;  ///< Coerces a value to a JavaScript object.
+
+ protected:
+  /// !cond INTERNAL
+  napi_env _env;
+  napi_value _value;
+  /// !endcond
+};
+
+/// A JavaScript boolean value.
+class Boolean : public Value {
+ public:
+  static Boolean New(napi_env env,  ///< Node-API environment
+                     bool value     ///< Boolean value
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Boolean();  ///< Creates a new _empty_ Boolean instance.
+  Boolean(napi_env env,
+          napi_value value);  ///< Wraps a Node-API value primitive.
+
+  operator bool() const;  ///< Converts a Boolean value to a boolean primitive.
+  bool Value() const;     ///< Converts a Boolean value to a boolean primitive.
+};
+
+/// A JavaScript number value.
+class Number : public Value {
+ public:
+  static Number New(napi_env env,  ///< Node-API environment
+                    double value   ///< Number value
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Number();  ///< Creates a new _empty_ Number instance.
+  Number(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+
+  operator int32_t()
+      const;  ///< Converts a Number value to a 32-bit signed integer value.
+  operator uint32_t()
+      const;  ///< Converts a Number value to a 32-bit unsigned integer value.
+  operator int64_t()
+      const;  ///< Converts a Number value to a 64-bit signed integer value.
+  operator float()
+      const;  ///< Converts a Number value to a 32-bit floating-point value.
+  operator double()
+      const;  ///< Converts a Number value to a 64-bit floating-point value.
+
+  int32_t Int32Value()
+      const;  ///< Converts a Number value to a 32-bit signed integer value.
+  uint32_t Uint32Value()
+      const;  ///< Converts a Number value to a 32-bit unsigned integer value.
+  int64_t Int64Value()
+      const;  ///< Converts a Number value to a 64-bit signed integer value.
+  float FloatValue()
+      const;  ///< Converts a Number value to a 32-bit floating-point value.
+  double DoubleValue()
+      const;  ///< Converts a Number value to a 64-bit floating-point value.
+};
+
+#if NAPI_VERSION > 5
+/// A JavaScript bigint value.
+class BigInt : public Value {
+ public:
+  static BigInt New(napi_env env,  ///< Node-API environment
+                    int64_t value  ///< Number value
+  );
+  static BigInt New(napi_env env,   ///< Node-API environment
+                    uint64_t value  ///< Number value
+  );
+
+  /// Creates a new BigInt object using a specified sign bit and a
+  /// specified list of digits/words.
+  /// The resulting number is calculated as:
+  /// (-1)^sign_bit * (words[0] * (2^64)^0 + words[1] * (2^64)^1 + ...)
+  static BigInt New(napi_env env,          ///< Node-API environment
+                    int sign_bit,          ///< Sign bit. 1 if negative.
+                    size_t word_count,     ///< Number of words in array
+                    const uint64_t* words  ///< Array of words
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  BigInt();  ///< Creates a new _empty_ BigInt instance.
+  BigInt(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+
+  int64_t Int64Value(bool* lossless)
+      const;  ///< Converts a BigInt value to a 64-bit signed integer value.
+  uint64_t Uint64Value(bool* lossless)
+      const;  ///< Converts a BigInt value to a 64-bit unsigned integer value.
+
+  size_t WordCount() const;  ///< The number of 64-bit words needed to store
+                             ///< the result of ToWords().
+
+  /// Writes the contents of this BigInt to a specified memory location.
+  /// `sign_bit` must be provided and will be set to 1 if this BigInt is
+  /// negative.
+  /// `*word_count` has to be initialized to the length of the `words` array.
+  /// Upon return, it will be set to the actual number of words that would
+  /// be needed to store this BigInt (i.e. the return value of `WordCount()`).
+  void ToWords(int* sign_bit, size_t* word_count, uint64_t* words);
+};
+#endif  // NAPI_VERSION > 5
+
+#if (NAPI_VERSION > 4)
+/// A JavaScript date value.
+class Date : public Value {
+ public:
+  /// Creates a new Date value from a double primitive.
+  static Date New(napi_env env,  ///< Node-API environment
+                  double value   ///< Number value
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Date();  ///< Creates a new _empty_ Date instance.
+  Date(napi_env env, napi_value value);  ///< Wraps a Node-API value primitive.
+  operator double() const;  ///< Converts a Date value to double primitive
+
+  double ValueOf() const;  ///< Converts a Date value to a double primitive.
+};
+#endif
+
+/// A JavaScript string or symbol value (that can be used as a property name).
+class Name : public Value {
+ public:
+  static void CheckCast(napi_env env, napi_value value);
+
+  Name();  ///< Creates a new _empty_ Name instance.
+  Name(napi_env env,
+       napi_value value);  ///< Wraps a Node-API value primitive.
+};
+
+/// A JavaScript string value.
+class String : public Name {
+ public:
+  /// Creates a new String value from a UTF-8 encoded C++ string.
+  static String New(napi_env env,             ///< Node-API environment
+                    const std::string& value  ///< UTF-8 encoded C++ string
+  );
+
+  /// Creates a new String value from a UTF-16 encoded C++ string.
+  static String New(napi_env env,                ///< Node-API environment
+                    const std::u16string& value  ///< UTF-16 encoded C++ string
+  );
+
+  /// Creates a new String value from a UTF-8 encoded C string.
+  static String New(
+      napi_env env,      ///< Node-API environment
+      const char* value  ///< UTF-8 encoded null-terminated C string
+  );
+
+  /// Creates a new String value from a UTF-16 encoded C string.
+  static String New(
+      napi_env env,          ///< Node-API environment
+      const char16_t* value  ///< UTF-16 encoded null-terminated C string
+  );
+
+  /// Creates a new String value from a UTF-8 encoded C string with specified
+  /// length.
+  static String New(napi_env env,       ///< Node-API environment
+                    const char* value,  ///< UTF-8 encoded C string (not
+                                        ///< necessarily null-terminated)
+                    size_t length       ///< length of the string in bytes
+  );
+
+  /// Creates a new String value from a UTF-16 encoded C string with specified
+  /// length.
+  static String New(
+      napi_env env,           ///< Node-API environment
+      const char16_t* value,  ///< UTF-16 encoded C string (not necessarily
+                              ///< null-terminated)
+      size_t length           ///< Length of the string in 2-byte code units
+  );
+
+  /// Creates a new String based on the original object's type.
+  ///
+  /// `value` may be any of:
+  /// - const char* (encoded using UTF-8, null-terminated)
+  /// - const char16_t* (encoded using UTF-16-LE, null-terminated)
+  /// - std::string (encoded using UTF-8)
+  /// - std::u16string
+  template <typename T>
+  static String From(napi_env env, const T& value);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  String();  ///< Creates a new _empty_ String instance.
+  String(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+
+  operator std::string()
+      const;  ///< Converts a String value to a UTF-8 encoded C++ string.
+  operator std::u16string()
+      const;  ///< Converts a String value to a UTF-16 encoded C++ string.
+  std::string Utf8Value()
+      const;  ///< Converts a String value to a UTF-8 encoded C++ string.
+  std::u16string Utf16Value()
+      const;  ///< Converts a String value to a UTF-16 encoded C++ string.
+};
+
+/// A JavaScript symbol value.
+class Symbol : public Name {
+ public:
+  /// Creates a new Symbol value with an optional description.
+  static Symbol New(
+      napi_env env,  ///< Node-API environment
+      const char* description =
+          nullptr  ///< Optional UTF-8 encoded null-terminated C string
+                   ///  describing the symbol
+  );
+
+  /// Creates a new Symbol value with a description.
+  static Symbol New(
+      napi_env env,  ///< Node-API environment
+      const std::string&
+          description  ///< UTF-8 encoded C++ string describing the symbol
+  );
+
+  /// Creates a new Symbol value with a description.
+  static Symbol New(napi_env env,       ///< Node-API environment
+                    String description  ///< String value describing the symbol
+  );
+
+  /// Creates a new Symbol value with a description.
+  static Symbol New(
+      napi_env env,           ///< Node-API environment
+      napi_value description  ///< String value describing the symbol
+  );
+
+  /// Get a public Symbol (e.g. Symbol.iterator).
+  static MaybeOrValue<Symbol> WellKnown(napi_env, const std::string& name);
+
+  // Create a symbol in the global registry, UTF-8 Encoded cpp string
+  static MaybeOrValue<Symbol> For(napi_env env, const std::string& description);
+
+  // Create a symbol in the global registry, C style string (null terminated)
+  static MaybeOrValue<Symbol> For(napi_env env, const char* description);
+
+  // Create a symbol in the global registry, String value describing the symbol
+  static MaybeOrValue<Symbol> For(napi_env env, String description);
+
+  // Create a symbol in the global registry, napi_value describing the symbol
+  static MaybeOrValue<Symbol> For(napi_env env, napi_value description);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Symbol();  ///< Creates a new _empty_ Symbol instance.
+  Symbol(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+};
+
+class TypeTaggable : public Value {
+ public:
+#if NAPI_VERSION >= 8
+  void TypeTag(const napi_type_tag* type_tag) const;
+  bool CheckTypeTag(const napi_type_tag* type_tag) const;
+#endif  // NAPI_VERSION >= 8
+ protected:
+  TypeTaggable();
+  TypeTaggable(napi_env env, napi_value value);
+};
+
+/// A JavaScript object value.
+class Object : public TypeTaggable {
+ public:
+  /// Enables property and element assignments using indexing syntax.
+  ///
+  /// This is a convenient helper to get and set object properties. As
+  /// getting and setting object properties may throw with JavaScript
+  /// exceptions, it is notable that these operations may fail.
+  /// When NODE_ADDON_API_ENABLE_MAYBE is defined, the process will abort
+  /// on JavaScript exceptions.
+  ///
+  /// Example:
+  ///
+  ///     Napi::Value propertyValue = object1['A'];
+  ///     object2['A'] = propertyValue;
+  ///     Napi::Value elementValue = array[0];
+  ///     array[1] = elementValue;
+  template <typename Key>
+  class PropertyLValue {
+   public:
+    /// Converts an L-value to a value.
+    operator Value() const;
+
+    /// Assigns a value to the property. The type of value can be
+    /// anything supported by `Object::Set`.
+    template <typename ValueType>
+    PropertyLValue& operator=(ValueType value);
+
+    /// Converts an L-value to a value. For convenience.
+    Value AsValue() const;
+
+   private:
+    PropertyLValue() = delete;
+    PropertyLValue(Object object, Key key);
+    napi_env _env;
+    napi_value _object;
+    Key _key;
+
+    friend class Napi::Object;
+  };
+
+  /// Creates a new Object value.
+  static Object New(napi_env env  ///< Node-API environment
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Object();  ///< Creates a new _empty_ Object instance.
+  Object(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+
+  /// Gets or sets a named property.
+  PropertyLValue<std::string> operator[](
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  );
+
+  /// Gets or sets a named property.
+  PropertyLValue<std::string> operator[](
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  );
+
+  /// Gets or sets an indexed property or array element.
+  PropertyLValue<uint32_t> operator[](
+      uint32_t index  /// Property / element index
+  );
+
+  /// Gets or sets an indexed property or array element.
+  PropertyLValue<Value> operator[](Value index  /// Property / element index
+  ) const;
+
+  /// Gets a named property.
+  MaybeOrValue<Value> operator[](
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Gets a named property.
+  MaybeOrValue<Value> operator[](
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Gets an indexed property or array element.
+  MaybeOrValue<Value> operator[](uint32_t index  ///< Property / element index
+  ) const;
+
+  /// Checks whether a property is present.
+  MaybeOrValue<bool> Has(napi_value key  ///< Property key primitive
+  ) const;
+
+  /// Checks whether a property is present.
+  MaybeOrValue<bool> Has(Value key  ///< Property key
+  ) const;
+
+  /// Checks whether a named property is present.
+  MaybeOrValue<bool> Has(
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Checks whether a named property is present.
+  MaybeOrValue<bool> Has(
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Checks whether a own property is present.
+  MaybeOrValue<bool> HasOwnProperty(napi_value key  ///< Property key primitive
+  ) const;
+
+  /// Checks whether a own property is present.
+  MaybeOrValue<bool> HasOwnProperty(Value key  ///< Property key
+  ) const;
+
+  /// Checks whether a own property is present.
+  MaybeOrValue<bool> HasOwnProperty(
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Checks whether a own property is present.
+  MaybeOrValue<bool> HasOwnProperty(
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Gets a property.
+  MaybeOrValue<Value> Get(napi_value key  ///< Property key primitive
+  ) const;
+
+  /// Gets a property.
+  MaybeOrValue<Value> Get(Value key  ///< Property key
+  ) const;
+
+  /// Gets a named property.
+  MaybeOrValue<Value> Get(
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Gets a named property.
+  MaybeOrValue<Value> Get(
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Sets a property.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(napi_value key,         ///< Property key primitive
+                         const ValueType& value  ///< Property value primitive
+  ) const;
+
+  /// Sets a property.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(Value key,              ///< Property key
+                         const ValueType& value  ///< Property value
+  ) const;
+
+  /// Sets a named property.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(
+      const char* utf8name,  ///< UTF-8 encoded null-terminated property name
+      const ValueType& value) const;
+
+  /// Sets a named property.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(
+      const std::string& utf8name,  ///< UTF-8 encoded property name
+      const ValueType& value        ///< Property value primitive
+  ) const;
+
+  /// Delete property.
+  MaybeOrValue<bool> Delete(napi_value key  ///< Property key primitive
+  ) const;
+
+  /// Delete property.
+  MaybeOrValue<bool> Delete(Value key  ///< Property key
+  ) const;
+
+  /// Delete property.
+  MaybeOrValue<bool> Delete(
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Delete property.
+  MaybeOrValue<bool> Delete(
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Checks whether an indexed property is present.
+  MaybeOrValue<bool> Has(uint32_t index  ///< Property / element index
+  ) const;
+
+  /// Gets an indexed property or array element.
+  MaybeOrValue<Value> Get(uint32_t index  ///< Property / element index
+  ) const;
+
+  /// Sets an indexed property or array element.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(uint32_t index,         ///< Property / element index
+                         const ValueType& value  ///< Property value primitive
+  ) const;
+
+  /// Deletes an indexed property or array element.
+  MaybeOrValue<bool> Delete(uint32_t index  ///< Property / element index
+  ) const;
+
+  /// This operation can fail in case of Proxy.[[OwnPropertyKeys]] and
+  /// Proxy.[[GetOwnProperty]] calling into JavaScript. See:
+  /// -
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys
+  /// -
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getownproperty-p
+  MaybeOrValue<Array> GetPropertyNames() const;  ///< Get all property names
+
+  /// Defines a property on the object.
+  ///
+  /// This operation can fail in case of Proxy.[[DefineOwnProperty]] calling
+  /// into JavaScript. See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc
+  MaybeOrValue<bool> DefineProperty(
+      const PropertyDescriptor&
+          property  ///< Descriptor for the property to be defined
+  ) const;
+
+  /// Defines properties on the object.
+  ///
+  /// This operation can fail in case of Proxy.[[DefineOwnProperty]] calling
+  /// into JavaScript. See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc
+  MaybeOrValue<bool> DefineProperties(
+      const std::initializer_list<PropertyDescriptor>& properties
+      ///< List of descriptors for the properties to be defined
+  ) const;
+
+  /// Defines properties on the object.
+  ///
+  /// This operation can fail in case of Proxy.[[DefineOwnProperty]] calling
+  /// into JavaScript. See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc
+  MaybeOrValue<bool> DefineProperties(
+      const std::vector<PropertyDescriptor>& properties
+      ///< Vector of descriptors for the properties to be defined
+  ) const;
+
+  /// Checks if an object is an instance created by a constructor function.
+  ///
+  /// This is equivalent to the JavaScript `instanceof` operator.
+  ///
+  /// This operation can fail in case of Proxy.[[GetPrototypeOf]] calling into
+  /// JavaScript.
+  /// See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof
+  MaybeOrValue<bool> InstanceOf(
+      const Function& constructor  ///< Constructor function
+  ) const;
+
+  template <typename Finalizer, typename T>
+  inline void AddFinalizer(Finalizer finalizeCallback, T* data) const;
+
+  template <typename Finalizer, typename T, typename Hint>
+  inline void AddFinalizer(Finalizer finalizeCallback,
+                           T* data,
+                           Hint* finalizeHint) const;
+
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+  class const_iterator;
+
+  inline const_iterator begin() const;
+
+  inline const_iterator end() const;
+
+  class iterator;
+
+  inline iterator begin();
+
+  inline iterator end();
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+
+#if NAPI_VERSION >= 8
+  /// This operation can fail in case of Proxy.[[GetPrototypeOf]] calling into
+  /// JavaScript.
+  /// See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof
+  MaybeOrValue<bool> Freeze() const;
+  /// This operation can fail in case of Proxy.[[GetPrototypeOf]] calling into
+  /// JavaScript.
+  /// See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof
+  MaybeOrValue<bool> Seal() const;
+#endif  // NAPI_VERSION >= 8
+};
+
+template <typename T>
+class External : public TypeTaggable {
+ public:
+  static External New(napi_env env, T* data);
+
+  // Finalizer must implement `void operator()(Env env, T* data)`.
+  template <typename Finalizer>
+  static External New(napi_env env, T* data, Finalizer finalizeCallback);
+  // Finalizer must implement `void operator()(Env env, T* data, Hint* hint)`.
+  template <typename Finalizer, typename Hint>
+  static External New(napi_env env,
+                      T* data,
+                      Finalizer finalizeCallback,
+                      Hint* finalizeHint);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  External();
+  External(napi_env env, napi_value value);
+
+  T* Data() const;
+};
+
+class Array : public Object {
+ public:
+  static Array New(napi_env env);
+  static Array New(napi_env env, size_t length);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Array();
+  Array(napi_env env, napi_value value);
+
+  uint32_t Length() const;
+};
+
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+class Object::const_iterator {
+ private:
+  enum class Type { BEGIN, END };
+
+  inline const_iterator(const Object* object, const Type type);
+
+ public:
+  inline const_iterator& operator++();
+
+  inline bool operator==(const const_iterator& other) const;
+
+  inline bool operator!=(const const_iterator& other) const;
+
+  inline const std::pair<Value, Object::PropertyLValue<Value>> operator*()
+      const;
+
+ private:
+  const Napi::Object* _object;
+  Array _keys;
+  uint32_t _index;
+
+  friend class Object;
+};
+
+class Object::iterator {
+ private:
+  enum class Type { BEGIN, END };
+
+  inline iterator(Object* object, const Type type);
+
+ public:
+  inline iterator& operator++();
+
+  inline bool operator==(const iterator& other) const;
+
+  inline bool operator!=(const iterator& other) const;
+
+  inline std::pair<Value, Object::PropertyLValue<Value>> operator*();
+
+ private:
+  Napi::Object* _object;
+  Array _keys;
+  uint32_t _index;
+
+  friend class Object;
+};
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+
+/// A JavaScript array buffer value.
+class ArrayBuffer : public Object {
+ public:
+  /// Creates a new ArrayBuffer instance over a new automatically-allocated
+  /// buffer.
+  static ArrayBuffer New(
+      napi_env env,      ///< Node-API environment
+      size_t byteLength  ///< Length of the buffer to be allocated, in bytes
+  );
+
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  /// Creates a new ArrayBuffer instance, using an external buffer with
+  /// specified byte length.
+  static ArrayBuffer New(
+      napi_env env,        ///< Node-API environment
+      void* externalData,  ///< Pointer to the external buffer to be used by
+                           ///< the array
+      size_t byteLength    ///< Length of the external buffer to be used by the
+                           ///< array, in bytes
+  );
+
+  /// Creates a new ArrayBuffer instance, using an external buffer with
+  /// specified byte length.
+  template <typename Finalizer>
+  static ArrayBuffer New(
+      napi_env env,        ///< Node-API environment
+      void* externalData,  ///< Pointer to the external buffer to be used by
+                           ///< the array
+      size_t byteLength,   ///< Length of the external buffer to be used by the
+                           ///< array,
+                           ///  in bytes
+      Finalizer finalizeCallback  ///< Function to be called when the array
+                                  ///< buffer is destroyed;
+                                  ///  must implement `void operator()(Env env,
+                                  ///  void* externalData)`
+  );
+
+  /// Creates a new ArrayBuffer instance, using an external buffer with
+  /// specified byte length.
+  template <typename Finalizer, typename Hint>
+  static ArrayBuffer New(
+      napi_env env,        ///< Node-API environment
+      void* externalData,  ///< Pointer to the external buffer to be used by
+                           ///< the array
+      size_t byteLength,   ///< Length of the external buffer to be used by the
+                           ///< array,
+                           ///  in bytes
+      Finalizer finalizeCallback,  ///< Function to be called when the array
+                                   ///< buffer is destroyed;
+                                   ///  must implement `void operator()(Env
+                                   ///  env, void* externalData, Hint* hint)`
+      Hint* finalizeHint  ///< Hint (second parameter) to be passed to the
+                          ///< finalize callback
+  );
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  ArrayBuffer();  ///< Creates a new _empty_ ArrayBuffer instance.
+  ArrayBuffer(napi_env env,
+              napi_value value);  ///< Wraps a Node-API value primitive.
+
+  void* Data();         ///< Gets a pointer to the data buffer.
+  size_t ByteLength();  ///< Gets the length of the array buffer in bytes.
+
+#if NAPI_VERSION >= 7
+  bool IsDetached() const;
+  void Detach();
+#endif  // NAPI_VERSION >= 7
+};
+
+/// A JavaScript typed-array value with unknown array type.
+///
+/// For type-specific operations, cast to a `TypedArrayOf<T>` instance using the
+/// `As()` method:
+///
+///     Napi::TypedArray array = ...
+///     if (t.TypedArrayType() == napi_int32_array) {
+///         Napi::Int32Array int32Array = t.As<Napi::Int32Array>();
+///     }
+class TypedArray : public Object {
+ public:
+  static void CheckCast(napi_env env, napi_value value);
+
+  TypedArray();  ///< Creates a new _empty_ TypedArray instance.
+  TypedArray(napi_env env,
+             napi_value value);  ///< Wraps a Node-API value primitive.
+
+  napi_typedarray_type TypedArrayType()
+      const;  ///< Gets the type of this typed-array.
+  Napi::ArrayBuffer ArrayBuffer() const;  ///< Gets the backing array buffer.
+
+  uint8_t ElementSize()
+      const;  ///< Gets the size in bytes of one element in the array.
+  size_t ElementLength() const;  ///< Gets the number of elements in the array.
+  size_t ByteOffset()
+      const;  ///< Gets the offset into the buffer where the array starts.
+  size_t ByteLength() const;  ///< Gets the length of the array in bytes.
+
+ protected:
+  /// !cond INTERNAL
+  napi_typedarray_type _type;
+  size_t _length;
+
+  TypedArray(napi_env env,
+             napi_value value,
+             napi_typedarray_type type,
+             size_t length);
+
+  template <typename T>
+  static
+#if defined(NAPI_HAS_CONSTEXPR)
+      constexpr
+#endif
+      napi_typedarray_type
+      TypedArrayTypeForPrimitiveType() {
+    return std::is_same<T, int8_t>::value     ? napi_int8_array
+           : std::is_same<T, uint8_t>::value  ? napi_uint8_array
+           : std::is_same<T, int16_t>::value  ? napi_int16_array
+           : std::is_same<T, uint16_t>::value ? napi_uint16_array
+           : std::is_same<T, int32_t>::value  ? napi_int32_array
+           : std::is_same<T, uint32_t>::value ? napi_uint32_array
+           : std::is_same<T, float>::value    ? napi_float32_array
+           : std::is_same<T, double>::value   ? napi_float64_array
+#if NAPI_VERSION > 5
+           : std::is_same<T, int64_t>::value  ? napi_bigint64_array
+           : std::is_same<T, uint64_t>::value ? napi_biguint64_array
+#endif  // NAPI_VERSION > 5
+                                              : napi_int8_array;
+  }
+  /// !endcond
+};
+
+/// A JavaScript typed-array value with known array type.
+///
+/// Note while it is possible to create and access Uint8 "clamped" arrays using
+/// this class, the _clamping_ behavior is only applied in JavaScript.
+template <typename T>
+class TypedArrayOf : public TypedArray {
+ public:
+  /// Creates a new TypedArray instance over a new automatically-allocated array
+  /// buffer.
+  ///
+  /// The array type parameter can normally be omitted (because it is inferred
+  /// from the template parameter T), except when creating a "clamped" array:
+  ///
+  ///     Uint8Array::New(env, length, napi_uint8_clamped_array)
+  static TypedArrayOf New(
+      napi_env env,          ///< Node-API environment
+      size_t elementLength,  ///< Length of the created array, as a number of
+                             ///< elements
+#if defined(NAPI_HAS_CONSTEXPR)
+      napi_typedarray_type type =
+          TypedArray::TypedArrayTypeForPrimitiveType<T>()
+#else
+      napi_typedarray_type type
+#endif
+      ///< Type of array, if different from the default array type for the
+      ///< template parameter T.
+  );
+
+  /// Creates a new TypedArray instance over a provided array buffer.
+  ///
+  /// The array type parameter can normally be omitted (because it is inferred
+  /// from the template parameter T), except when creating a "clamped" array:
+  ///
+  ///     Uint8Array::New(env, length, buffer, 0, napi_uint8_clamped_array)
+  static TypedArrayOf New(
+      napi_env env,          ///< Node-API environment
+      size_t elementLength,  ///< Length of the created array, as a number of
+                             ///< elements
+      Napi::ArrayBuffer arrayBuffer,  ///< Backing array buffer instance to use
+      size_t bufferOffset,  ///< Offset into the array buffer where the
+                            ///< typed-array starts
+#if defined(NAPI_HAS_CONSTEXPR)
+      napi_typedarray_type type =
+          TypedArray::TypedArrayTypeForPrimitiveType<T>()
+#else
+      napi_typedarray_type type
+#endif
+      ///< Type of array, if different from the default array type for the
+      ///< template parameter T.
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  TypedArrayOf();  ///< Creates a new _empty_ TypedArrayOf instance.
+  TypedArrayOf(napi_env env,
+               napi_value value);  ///< Wraps a Node-API value primitive.
+
+  T& operator[](size_t index);  ///< Gets or sets an element in the array.
+  const T& operator[](size_t index) const;  ///< Gets an element in the array.
+
+  /// Gets a pointer to the array's backing buffer.
+  ///
+  /// This is not necessarily the same as the `ArrayBuffer::Data()` pointer,
+  /// because the typed-array may have a non-zero `ByteOffset()` into the
+  /// `ArrayBuffer`.
+  T* Data();
+
+  /// Gets a pointer to the array's backing buffer.
+  ///
+  /// This is not necessarily the same as the `ArrayBuffer::Data()` pointer,
+  /// because the typed-array may have a non-zero `ByteOffset()` into the
+  /// `ArrayBuffer`.
+  const T* Data() const;
+
+ private:
+  T* _data;
+
+  TypedArrayOf(napi_env env,
+               napi_value value,
+               napi_typedarray_type type,
+               size_t length,
+               T* data);
+};
+
+/// The DataView provides a low-level interface for reading/writing multiple
+/// number types in an ArrayBuffer irrespective of the platform's endianness.
+class DataView : public Object {
+ public:
+  static DataView New(napi_env env, Napi::ArrayBuffer arrayBuffer);
+  static DataView New(napi_env env,
+                      Napi::ArrayBuffer arrayBuffer,
+                      size_t byteOffset);
+  static DataView New(napi_env env,
+                      Napi::ArrayBuffer arrayBuffer,
+                      size_t byteOffset,
+                      size_t byteLength);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  DataView();  ///< Creates a new _empty_ DataView instance.
+  DataView(napi_env env,
+           napi_value value);  ///< Wraps a Node-API value primitive.
+
+  Napi::ArrayBuffer ArrayBuffer() const;  ///< Gets the backing array buffer.
+  size_t ByteOffset()
+      const;  ///< Gets the offset into the buffer where the array starts.
+  size_t ByteLength() const;  ///< Gets the length of the array in bytes.
+
+  void* Data() const;
+
+  float GetFloat32(size_t byteOffset) const;
+  double GetFloat64(size_t byteOffset) const;
+  int8_t GetInt8(size_t byteOffset) const;
+  int16_t GetInt16(size_t byteOffset) const;
+  int32_t GetInt32(size_t byteOffset) const;
+  uint8_t GetUint8(size_t byteOffset) const;
+  uint16_t GetUint16(size_t byteOffset) const;
+  uint32_t GetUint32(size_t byteOffset) const;
+
+  void SetFloat32(size_t byteOffset, float value) const;
+  void SetFloat64(size_t byteOffset, double value) const;
+  void SetInt8(size_t byteOffset, int8_t value) const;
+  void SetInt16(size_t byteOffset, int16_t value) const;
+  void SetInt32(size_t byteOffset, int32_t value) const;
+  void SetUint8(size_t byteOffset, uint8_t value) const;
+  void SetUint16(size_t byteOffset, uint16_t value) const;
+  void SetUint32(size_t byteOffset, uint32_t value) const;
+
+ private:
+  template <typename T>
+  T ReadData(size_t byteOffset) const;
+
+  template <typename T>
+  void WriteData(size_t byteOffset, T value) const;
+
+  void* _data{};
+  size_t _length{};
+};
+
+class Function : public Object {
+ public:
+  using VoidCallback = void (*)(const CallbackInfo& info);
+  using Callback = Value (*)(const CallbackInfo& info);
+
+  template <VoidCallback cb>
+  static Function New(napi_env env,
+                      const char* utf8name = nullptr,
+                      void* data = nullptr);
+
+  template <Callback cb>
+  static Function New(napi_env env,
+                      const char* utf8name = nullptr,
+                      void* data = nullptr);
+
+  template <VoidCallback cb>
+  static Function New(napi_env env,
+                      const std::string& utf8name,
+                      void* data = nullptr);
+
+  template <Callback cb>
+  static Function New(napi_env env,
+                      const std::string& utf8name,
+                      void* data = nullptr);
+
+  /// Callable must implement operator() accepting a const CallbackInfo&
+  /// and return either void or Value.
+  template <typename Callable>
+  static Function New(napi_env env,
+                      Callable cb,
+                      const char* utf8name = nullptr,
+                      void* data = nullptr);
+  /// Callable must implement operator() accepting a const CallbackInfo&
+  /// and return either void or Value.
+  template <typename Callable>
+  static Function New(napi_env env,
+                      Callable cb,
+                      const std::string& utf8name,
+                      void* data = nullptr);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Function();
+  Function(napi_env env, napi_value value);
+
+  MaybeOrValue<Value> operator()(
+      const std::initializer_list<napi_value>& args) const;
+
+  MaybeOrValue<Value> Call(const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Value> Call(const std::vector<napi_value>& args) const;
+  MaybeOrValue<Value> Call(const std::vector<Value>& args) const;
+  MaybeOrValue<Value> Call(size_t argc, const napi_value* args) const;
+  MaybeOrValue<Value> Call(napi_value recv,
+                           const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Value> Call(napi_value recv,
+                           const std::vector<napi_value>& args) const;
+  MaybeOrValue<Value> Call(napi_value recv,
+                           const std::vector<Value>& args) const;
+  MaybeOrValue<Value> Call(napi_value recv,
+                           size_t argc,
+                           const napi_value* args) const;
+
+  MaybeOrValue<Value> MakeCallback(
+      napi_value recv,
+      const std::initializer_list<napi_value>& args,
+      napi_async_context context = nullptr) const;
+  MaybeOrValue<Value> MakeCallback(napi_value recv,
+                                   const std::vector<napi_value>& args,
+                                   napi_async_context context = nullptr) const;
+  MaybeOrValue<Value> MakeCallback(napi_value recv,
+                                   size_t argc,
+                                   const napi_value* args,
+                                   napi_async_context context = nullptr) const;
+
+  MaybeOrValue<Object> New(const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Object> New(const std::vector<napi_value>& args) const;
+  MaybeOrValue<Object> New(size_t argc, const napi_value* args) const;
+};
+
+class Promise : public Object {
+ public:
+  class Deferred {
+   public:
+    static Deferred New(napi_env env);
+    Deferred(napi_env env);
+
+    Napi::Promise Promise() const;
+    Napi::Env Env() const;
+
+    void Resolve(napi_value value) const;
+    void Reject(napi_value value) const;
+
+   private:
+    napi_env _env;
+    napi_deferred _deferred;
+    napi_value _promise;
+  };
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Promise();
+  Promise(napi_env env, napi_value value);
+
+  MaybeOrValue<Promise> Then(napi_value onFulfilled) const;
+  MaybeOrValue<Promise> Then(napi_value onFulfilled,
+                             napi_value onRejected) const;
+  MaybeOrValue<Promise> Catch(napi_value onRejected) const;
+
+  MaybeOrValue<Promise> Then(const Function& onFulfilled) const;
+  MaybeOrValue<Promise> Then(const Function& onFulfilled,
+                             const Function& onRejected) const;
+  MaybeOrValue<Promise> Catch(const Function& onRejected) const;
+};
+
+template <typename T>
+class Buffer : public Uint8Array {
+ public:
+  static Buffer<T> New(napi_env env, size_t length);
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  static Buffer<T> New(napi_env env, T* data, size_t length);
+
+  // Finalizer must implement `void operator()(Env env, T* data)`.
+  template <typename Finalizer>
+  static Buffer<T> New(napi_env env,
+                       T* data,
+                       size_t length,
+                       Finalizer finalizeCallback);
+  // Finalizer must implement `void operator()(Env env, T* data, Hint* hint)`.
+  template <typename Finalizer, typename Hint>
+  static Buffer<T> New(napi_env env,
+                       T* data,
+                       size_t length,
+                       Finalizer finalizeCallback,
+                       Hint* finalizeHint);
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+
+  static Buffer<T> NewOrCopy(napi_env env, T* data, size_t length);
+  // Finalizer must implement `void operator()(Env env, T* data)`.
+  template <typename Finalizer>
+  static Buffer<T> NewOrCopy(napi_env env,
+                             T* data,
+                             size_t length,
+                             Finalizer finalizeCallback);
+  // Finalizer must implement `void operator()(Env env, T* data, Hint* hint)`.
+  template <typename Finalizer, typename Hint>
+  static Buffer<T> NewOrCopy(napi_env env,
+                             T* data,
+                             size_t length,
+                             Finalizer finalizeCallback,
+                             Hint* finalizeHint);
+
+  static Buffer<T> Copy(napi_env env, const T* data, size_t length);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Buffer();
+  Buffer(napi_env env, napi_value value);
+  size_t Length() const;
+  T* Data() const;
+
+ private:
+};
+
+/// Holds a counted reference to a value; initially a weak reference unless
+/// otherwise specified, may be changed to/from a strong reference by adjusting
+/// the refcount.
+///
+/// The referenced value is not immediately destroyed when the reference count
+/// is zero; it is merely then eligible for garbage-collection if there are no
+/// other references to the value.
+template <typename T>
+class Reference {
+ public:
+  static Reference<T> New(const T& value, uint32_t initialRefcount = 0);
+
+  Reference();
+  Reference(napi_env env, napi_ref ref);
+  ~Reference();
+
+  // A reference can be moved but cannot be copied.
+  Reference(Reference<T>&& other);
+  Reference<T>& operator=(Reference<T>&& other);
+  NAPI_DISALLOW_ASSIGN(Reference<T>)
+
+  operator napi_ref() const;
+  bool operator==(const Reference<T>& other) const;
+  bool operator!=(const Reference<T>& other) const;
+
+  Napi::Env Env() const;
+  bool IsEmpty() const;
+
+  // Note when getting the value of a Reference it is usually correct to do so
+  // within a HandleScope so that the value handle gets cleaned up efficiently.
+  T Value() const;
+
+  uint32_t Ref() const;
+  uint32_t Unref() const;
+  void Reset();
+  void Reset(const T& value, uint32_t refcount = 0);
+
+  // Call this on a reference that is declared as static data, to prevent its
+  // destructor from running at program shutdown time, which would attempt to
+  // reset the reference when the environment is no longer valid. Avoid using
+  // this if at all possible. If you do need to use static data, MAKE SURE to
+  // warn your users that your addon is NOT threadsafe.
+  void SuppressDestruct();
+
+ protected:
+  Reference(const Reference<T>&);
+
+  /// !cond INTERNAL
+  napi_env _env;
+  napi_ref _ref;
+  /// !endcond
+
+ private:
+  bool _suppressDestruct;
+};
+
+class ObjectReference : public Reference<Object> {
+ public:
+  ObjectReference();
+  ObjectReference(napi_env env, napi_ref ref);
+
+  // A reference can be moved but cannot be copied.
+  ObjectReference(Reference<Object>&& other);
+  ObjectReference& operator=(Reference<Object>&& other);
+  ObjectReference(ObjectReference&& other);
+  ObjectReference& operator=(ObjectReference&& other);
+  NAPI_DISALLOW_ASSIGN(ObjectReference)
+
+  MaybeOrValue<Napi::Value> Get(const char* utf8name) const;
+  MaybeOrValue<Napi::Value> Get(const std::string& utf8name) const;
+  MaybeOrValue<bool> Set(const char* utf8name, napi_value value) const;
+  MaybeOrValue<bool> Set(const char* utf8name, Napi::Value value) const;
+  MaybeOrValue<bool> Set(const char* utf8name, const char* utf8value) const;
+  MaybeOrValue<bool> Set(const char* utf8name, bool boolValue) const;
+  MaybeOrValue<bool> Set(const char* utf8name, double numberValue) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name, napi_value value) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name, Napi::Value value) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name,
+                         std::string& utf8value) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name, bool boolValue) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name, double numberValue) const;
+
+  MaybeOrValue<Napi::Value> Get(uint32_t index) const;
+  MaybeOrValue<bool> Set(uint32_t index, const napi_value value) const;
+  MaybeOrValue<bool> Set(uint32_t index, const Napi::Value value) const;
+  MaybeOrValue<bool> Set(uint32_t index, const char* utf8value) const;
+  MaybeOrValue<bool> Set(uint32_t index, const std::string& utf8value) const;
+  MaybeOrValue<bool> Set(uint32_t index, bool boolValue) const;
+  MaybeOrValue<bool> Set(uint32_t index, double numberValue) const;
+
+ protected:
+  ObjectReference(const ObjectReference&);
+};
+
+class FunctionReference : public Reference<Function> {
+ public:
+  FunctionReference();
+  FunctionReference(napi_env env, napi_ref ref);
+
+  // A reference can be moved but cannot be copied.
+  FunctionReference(Reference<Function>&& other);
+  FunctionReference& operator=(Reference<Function>&& other);
+  FunctionReference(FunctionReference&& other);
+  FunctionReference& operator=(FunctionReference&& other);
+  NAPI_DISALLOW_ASSIGN_COPY(FunctionReference)
+
+  MaybeOrValue<Napi::Value> operator()(
+      const std::initializer_list<napi_value>& args) const;
+
+  MaybeOrValue<Napi::Value> Call(
+      const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Napi::Value> Call(const std::vector<napi_value>& args) const;
+  MaybeOrValue<Napi::Value> Call(
+      napi_value recv, const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Napi::Value> Call(napi_value recv,
+                                 const std::vector<napi_value>& args) const;
+  MaybeOrValue<Napi::Value> Call(napi_value recv,
+                                 size_t argc,
+                                 const napi_value* args) const;
+
+  MaybeOrValue<Napi::Value> MakeCallback(
+      napi_value recv,
+      const std::initializer_list<napi_value>& args,
+      napi_async_context context = nullptr) const;
+  MaybeOrValue<Napi::Value> MakeCallback(
+      napi_value recv,
+      const std::vector<napi_value>& args,
+      napi_async_context context = nullptr) const;
+  MaybeOrValue<Napi::Value> MakeCallback(
+      napi_value recv,
+      size_t argc,
+      const napi_value* args,
+      napi_async_context context = nullptr) const;
+
+  MaybeOrValue<Object> New(const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Object> New(const std::vector<napi_value>& args) const;
+};
+
+// Shortcuts to creating a new reference with inferred type and refcount = 0.
+template <typename T>
+Reference<T> Weak(T value);
+ObjectReference Weak(Object value);
+FunctionReference Weak(Function value);
+
+// Shortcuts to creating a new reference with inferred type and refcount = 1.
+template <typename T>
+Reference<T> Persistent(T value);
+ObjectReference Persistent(Object value);
+FunctionReference Persistent(Function value);
+
+/// A persistent reference to a JavaScript error object. Use of this class
+/// depends somewhat on whether C++ exceptions are enabled at compile time.
+///
+/// ### Handling Errors With C++ Exceptions
+///
+/// If C++ exceptions are enabled, then the `Error` class extends
+/// `std::exception` and enables integrated error-handling for C++ exceptions
+/// and JavaScript exceptions.
+///
+/// If a Node-API call fails without executing any JavaScript code (for
+/// example due to an invalid argument), then the Node-API wrapper
+/// automatically converts and throws the error as a C++ exception of type
+/// `Napi::Error`. Or if a JavaScript function called by C++ code via Node-API
+/// throws a JavaScript exception, then the Node-API wrapper automatically
+/// converts and throws it as a C++ exception of type `Napi::Error`.
+///
+/// If a C++ exception of type `Napi::Error` escapes from a Node-API C++
+/// callback, then the Node-API wrapper automatically converts and throws it
+/// as a JavaScript exception. Therefore, catching a C++ exception of type
+/// `Napi::Error` prevents a JavaScript exception from being thrown.
+///
+/// #### Example 1A - Throwing a C++ exception:
+///
+///     Napi::Env env = ...
+///     throw Napi::Error::New(env, "Example exception");
+///
+/// Following C++ statements will not be executed. The exception will bubble
+/// up as a C++ exception of type `Napi::Error`, until it is either caught
+/// while still in C++, or else automatically propagated as a JavaScript
+/// exception when the callback returns to JavaScript.
+///
+/// #### Example 2A - Propagating a Node-API C++ exception:
+///
+///     Napi::Function jsFunctionThatThrows = someObj.As<Napi::Function>();
+///     Napi::Value result = jsFunctionThatThrows({ arg1, arg2 });
+///
+/// Following C++ statements will not be executed. The exception will bubble
+/// up as a C++ exception of type `Napi::Error`, until it is either caught
+/// while still in C++, or else automatically propagated as a JavaScript
+/// exception when the callback returns to JavaScript.
+///
+/// #### Example 3A - Handling a Node-API C++ exception:
+///
+///     Napi::Function jsFunctionThatThrows = someObj.As<Napi::Function>();
+///     Napi::Value result;
+///     try {
+///        result = jsFunctionThatThrows({ arg1, arg2 });
+///     } catch (const Napi::Error& e) {
+///       cerr << "Caught JavaScript exception: " + e.what();
+///     }
+///
+/// Since the exception was caught here, it will not be propagated as a
+/// JavaScript exception.
+///
+/// ### Handling Errors Without C++ Exceptions
+///
+/// If C++ exceptions are disabled (by defining
+/// `NODE_ADDON_API_DISABLE_CPP_EXCEPTIONS`) then this class does not extend
+/// `std::exception`, and APIs in the `Napi` namespace do not throw C++
+/// exceptions when they fail. Instead, they raise _pending_ JavaScript
+/// exceptions and return _empty_ `Value`s. Calling code should check
+/// `Value::IsEmpty()` before attempting to use a returned value, and may use
+/// methods on the `Env` class to check for, get, and clear a pending JavaScript
+/// exception. If the pending exception is not cleared, it will be thrown when
+/// the native callback returns to JavaScript.
+///
+/// #### Example 1B - Throwing a JS exception
+///
+///     Napi::Env env = ...
+///     Napi::Error::New(env, "Example
+///     exception").ThrowAsJavaScriptException(); return;
+///
+/// After throwing a JS exception, the code should generally return
+/// immediately from the native callback, after performing any necessary
+/// cleanup.
+///
+/// #### Example 2B - Propagating a Node-API JS exception:
+///
+///     Napi::Function jsFunctionThatThrows = someObj.As<Napi::Function>();
+///     Napi::Value result = jsFunctionThatThrows({ arg1, arg2 });
+///     if (result.IsEmpty()) return;
+///
+/// An empty value result from a Node-API call indicates an error occurred,
+/// and a JavaScript exception is pending. To let the exception propagate, the
+/// code should generally return immediately from the native callback, after
+/// performing any necessary cleanup.
+///
+/// #### Example 3B - Handling a Node-API JS exception:
+///
+///     Napi::Function jsFunctionThatThrows = someObj.As<Napi::Function>();
+///     Napi::Value result = jsFunctionThatThrows({ arg1, arg2 });
+///     if (result.IsEmpty()) {
+///       Napi::Error e = env.GetAndClearPendingException();
+///       cerr << "Caught JavaScript exception: " + e.Message();
+///     }
+///
+/// Since the exception was cleared here, it will not be propagated as a
+/// JavaScript exception after the native callback returns.
+class Error : public ObjectReference
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+    ,
+              public std::exception
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+{
+ public:
+  static Error New(napi_env env);
+  static Error New(napi_env env, const char* message);
+  static Error New(napi_env env, const std::string& message);
+
+  static NAPI_NO_RETURN void Fatal(const char* location, const char* message);
+
+  Error();
+  Error(napi_env env, napi_value value);
+
+  // An error can be moved or copied.
+  Error(Error&& other);
+  Error& operator=(Error&& other);
+  Error(const Error&);
+  Error& operator=(const Error&);
+
+  const std::string& Message() const NAPI_NOEXCEPT;
+  void ThrowAsJavaScriptException() const;
+
+  Object Value() const;
+
+#ifdef NODE_ADDON_API_CPP_EXCEPTIONS
+  const char* what() const NAPI_NOEXCEPT override;
+#endif  // NODE_ADDON_API_CPP_EXCEPTIONS
+
+ protected:
+  /// !cond INTERNAL
+  using create_error_fn = napi_status (*)(napi_env envb,
+                                          napi_value code,
+                                          napi_value msg,
+                                          napi_value* result);
+
+  template <typename TError>
+  static TError New(napi_env env,
+                    const char* message,
+                    size_t length,
+                    create_error_fn create_error);
+  /// !endcond
+
+ private:
+  static inline const char* ERROR_WRAP_VALUE() NAPI_NOEXCEPT;
+  mutable std::string _message;
+};
+
+class TypeError : public Error {
+ public:
+  static TypeError New(napi_env env, const char* message);
+  static TypeError New(napi_env env, const std::string& message);
+
+  TypeError();
+  TypeError(napi_env env, napi_value value);
+};
+
+class RangeError : public Error {
+ public:
+  static RangeError New(napi_env env, const char* message);
+  static RangeError New(napi_env env, const std::string& message);
+
+  RangeError();
+  RangeError(napi_env env, napi_value value);
+};
+
+#if NAPI_VERSION > 8
+class SyntaxError : public Error {
+ public:
+  static SyntaxError New(napi_env env, const char* message);
+  static SyntaxError New(napi_env env, const std::string& message);
+
+  SyntaxError();
+  SyntaxError(napi_env env, napi_value value);
+};
+#endif  // NAPI_VERSION > 8
+
+class CallbackInfo {
+ public:
+  CallbackInfo(napi_env env, napi_callback_info info);
+  ~CallbackInfo();
+
+  // Disallow copying to prevent multiple free of _dynamicArgs
+  NAPI_DISALLOW_ASSIGN_COPY(CallbackInfo)
+
+  Napi::Env Env() const;
+  Value NewTarget() const;
+  bool IsConstructCall() const;
+  size_t Length() const;
+  const Value operator[](size_t index) const;
+  Value This() const;
+  void* Data() const;
+  void SetData(void* data);
+  explicit operator napi_callback_info() const;
+
+ private:
+  const size_t _staticArgCount = 6;
+  napi_env _env;
+  napi_callback_info _info;
+  napi_value _this;
+  size_t _argc;
+  napi_value* _argv;
+  napi_value _staticArgs[6]{};
+  napi_value* _dynamicArgs;
+  void* _data;
+};
+
+class PropertyDescriptor {
+ public:
+  using GetterCallback = Napi::Value (*)(const Napi::CallbackInfo& info);
+  using SetterCallback = void (*)(const Napi::CallbackInfo& info);
+
+#ifndef NODE_ADDON_API_DISABLE_DEPRECATED
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      const char* utf8name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      const std::string& utf8name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      napi_value name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      Name name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      const char* utf8name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      const std::string& utf8name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      napi_value name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      Name name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      const char* utf8name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      const std::string& utf8name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      napi_value name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      Name name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+#endif  // !NODE_ADDON_API_DISABLE_DEPRECATED
+
+  template <GetterCallback Getter>
+  static PropertyDescriptor Accessor(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter>
+  static PropertyDescriptor Accessor(
+      const std::string& utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter>
+  static PropertyDescriptor Accessor(
+      Name name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter, SetterCallback Setter>
+  static PropertyDescriptor Accessor(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter, SetterCallback Setter>
+  static PropertyDescriptor Accessor(
+      const std::string& utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter, SetterCallback Setter>
+  static PropertyDescriptor Accessor(
+      Name name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      const char* utf8name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      const std::string& utf8name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      Name name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      const char* utf8name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      const std::string& utf8name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      Name name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      Napi::Env env,
+      Napi::Object object,
+      const char* utf8name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      Napi::Env env,
+      Napi::Object object,
+      const std::string& utf8name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      Napi::Env env,
+      Napi::Object object,
+      Name name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor Value(
+      const char* utf8name,
+      napi_value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor Value(
+      const std::string& utf8name,
+      napi_value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor Value(
+      napi_value name,
+      napi_value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor Value(
+      Name name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+
+  PropertyDescriptor(napi_property_descriptor desc);
+
+  operator napi_property_descriptor&();
+  operator const napi_property_descriptor&() const;
+
+ private:
+  napi_property_descriptor _desc;
+};
+
+/// Property descriptor for use with `ObjectWrap::DefineClass()`.
+///
+/// This is different from the standalone `PropertyDescriptor` because it is
+/// specific to each `ObjectWrap<T>` subclass. This prevents using descriptors
+/// from a different class when defining a new class (preventing the callbacks
+/// from having incorrect `this` pointers).
+template <typename T>
+class ClassPropertyDescriptor {
+ public:
+  ClassPropertyDescriptor(napi_property_descriptor desc) : _desc(desc) {}
+
+  operator napi_property_descriptor&() { return _desc; }
+  operator const napi_property_descriptor&() const { return _desc; }
+
+ private:
+  napi_property_descriptor _desc;
+};
+
+template <typename T, typename TCallback>
+struct MethodCallbackData {
+  TCallback callback;
+  void* data;
+};
+
+template <typename T, typename TGetterCallback, typename TSetterCallback>
+struct AccessorCallbackData {
+  TGetterCallback getterCallback;
+  TSetterCallback setterCallback;
+  void* data;
+};
+
+template <typename T>
+class InstanceWrap {
+ public:
+  using InstanceVoidMethodCallback = void (T::*)(const CallbackInfo& info);
+  using InstanceMethodCallback = Napi::Value (T::*)(const CallbackInfo& info);
+  using InstanceGetterCallback = Napi::Value (T::*)(const CallbackInfo& info);
+  using InstanceSetterCallback = void (T::*)(const CallbackInfo& info,
+                                             const Napi::Value& value);
+
+  using PropertyDescriptor = ClassPropertyDescriptor<T>;
+
+  static PropertyDescriptor InstanceMethod(
+      const char* utf8name,
+      InstanceVoidMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceMethod(
+      const char* utf8name,
+      InstanceMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceMethod(
+      Symbol name,
+      InstanceVoidMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceMethod(
+      Symbol name,
+      InstanceMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceVoidMethodCallback method>
+  static PropertyDescriptor InstanceMethod(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceMethodCallback method>
+  static PropertyDescriptor InstanceMethod(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceVoidMethodCallback method>
+  static PropertyDescriptor InstanceMethod(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceMethodCallback method>
+  static PropertyDescriptor InstanceMethod(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceAccessor(
+      const char* utf8name,
+      InstanceGetterCallback getter,
+      InstanceSetterCallback setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceAccessor(
+      Symbol name,
+      InstanceGetterCallback getter,
+      InstanceSetterCallback setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceGetterCallback getter,
+            InstanceSetterCallback setter = nullptr>
+  static PropertyDescriptor InstanceAccessor(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceGetterCallback getter,
+            InstanceSetterCallback setter = nullptr>
+  static PropertyDescriptor InstanceAccessor(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceValue(
+      const char* utf8name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor InstanceValue(
+      Symbol name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+
+ protected:
+  static void AttachPropData(napi_env env,
+                             napi_value value,
+                             const napi_property_descriptor* prop);
+
+ private:
+  using This = InstanceWrap<T>;
+
+  using InstanceVoidMethodCallbackData =
+      MethodCallbackData<T, InstanceVoidMethodCallback>;
+  using InstanceMethodCallbackData =
+      MethodCallbackData<T, InstanceMethodCallback>;
+  using InstanceAccessorCallbackData =
+      AccessorCallbackData<T, InstanceGetterCallback, InstanceSetterCallback>;
+
+  static napi_value InstanceVoidMethodCallbackWrapper(napi_env env,
+                                                      napi_callback_info info);
+  static napi_value InstanceMethodCallbackWrapper(napi_env env,
+                                                  napi_callback_info info);
+  static napi_value InstanceGetterCallbackWrapper(napi_env env,
+                                                  napi_callback_info info);
+  static napi_value InstanceSetterCallbackWrapper(napi_env env,
+                                                  napi_callback_info info);
+
+  template <InstanceSetterCallback method>
+  static napi_value WrappedMethod(napi_env env,
+                                  napi_callback_info info) NAPI_NOEXCEPT;
+
+  template <InstanceSetterCallback setter>
+  struct SetterTag {};
+
+  template <InstanceSetterCallback setter>
+  static napi_callback WrapSetter(SetterTag<setter>) NAPI_NOEXCEPT {
+    return &This::WrappedMethod<setter>;
+  }
+  static napi_callback WrapSetter(SetterTag<nullptr>) NAPI_NOEXCEPT {
+    return nullptr;
+  }
+};
+
+/// Base class to be extended by C++ classes exposed to JavaScript; each C++
+/// class instance gets "wrapped" by a JavaScript object that is managed by this
+/// class.
+///
+/// At initialization time, the `DefineClass()` method must be used to
+/// hook up the accessor and method callbacks. It takes a list of
+/// property descriptors, which can be constructed via the various
+/// static methods on the base class.
+///
+/// #### Example:
+///
+///     class Example: public Napi::ObjectWrap<Example> {
+///       public:
+///         static void Initialize(Napi::Env& env, Napi::Object& target) {
+///           Napi::Function constructor = DefineClass(env, "Example", {
+///             InstanceAccessor<&Example::GetSomething,
+///             &Example::SetSomething>("value"),
+///             InstanceMethod<&Example::DoSomething>("doSomething"),
+///           });
+///           target.Set("Example", constructor);
+///         }
+///
+///         Example(const Napi::CallbackInfo& info); // Constructor
+///         Napi::Value GetSomething(const Napi::CallbackInfo& info);
+///         void SetSomething(const Napi::CallbackInfo& info, const Napi::Value&
+///         value); Napi::Value DoSomething(const Napi::CallbackInfo& info);
+///     }
+template <typename T>
+class ObjectWrap : public InstanceWrap<T>, public Reference<Object> {
+ public:
+  ObjectWrap(const CallbackInfo& callbackInfo);
+  virtual ~ObjectWrap();
+
+  static T* Unwrap(Object wrapper);
+
+  // Methods exposed to JavaScript must conform to one of these callback
+  // signatures.
+  using StaticVoidMethodCallback = void (*)(const CallbackInfo& info);
+  using StaticMethodCallback = Napi::Value (*)(const CallbackInfo& info);
+  using StaticGetterCallback = Napi::Value (*)(const CallbackInfo& info);
+  using StaticSetterCallback = void (*)(const CallbackInfo& info,
+                                        const Napi::Value& value);
+
+  using PropertyDescriptor = ClassPropertyDescriptor<T>;
+
+  static Function DefineClass(
+      Napi::Env env,
+      const char* utf8name,
+      const std::initializer_list<PropertyDescriptor>& properties,
+      void* data = nullptr);
+  static Function DefineClass(Napi::Env env,
+                              const char* utf8name,
+                              const std::vector<PropertyDescriptor>& properties,
+                              void* data = nullptr);
+  static PropertyDescriptor StaticMethod(
+      const char* utf8name,
+      StaticVoidMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticMethod(
+      const char* utf8name,
+      StaticMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticMethod(
+      Symbol name,
+      StaticVoidMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticMethod(
+      Symbol name,
+      StaticMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticVoidMethodCallback method>
+  static PropertyDescriptor StaticMethod(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticVoidMethodCallback method>
+  static PropertyDescriptor StaticMethod(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticMethodCallback method>
+  static PropertyDescriptor StaticMethod(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticMethodCallback method>
+  static PropertyDescriptor StaticMethod(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticAccessor(
+      const char* utf8name,
+      StaticGetterCallback getter,
+      StaticSetterCallback setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticAccessor(
+      Symbol name,
+      StaticGetterCallback getter,
+      StaticSetterCallback setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticGetterCallback getter, StaticSetterCallback setter = nullptr>
+  static PropertyDescriptor StaticAccessor(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticGetterCallback getter, StaticSetterCallback setter = nullptr>
+  static PropertyDescriptor StaticAccessor(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticValue(
+      const char* utf8name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor StaticValue(
+      Symbol name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+  static Napi::Value OnCalledAsFunction(const Napi::CallbackInfo& callbackInfo);
+  virtual void Finalize(Napi::Env env);
+  virtual void Finalize(BasicEnv env);
+
+ private:
+  using This = ObjectWrap<T>;
+
+  static napi_value ConstructorCallbackWrapper(napi_env env,
+                                               napi_callback_info info);
+  static napi_value StaticVoidMethodCallbackWrapper(napi_env env,
+                                                    napi_callback_info info);
+  static napi_value StaticMethodCallbackWrapper(napi_env env,
+                                                napi_callback_info info);
+  static napi_value StaticGetterCallbackWrapper(napi_env env,
+                                                napi_callback_info info);
+  static napi_value StaticSetterCallbackWrapper(napi_env env,
+                                                napi_callback_info info);
+  static void FinalizeCallback(node_addon_api_basic_env env,
+                               void* data,
+                               void* hint);
+
+  static void PostFinalizeCallback(napi_env env, void* data, void* hint);
+
+  static Function DefineClass(Napi::Env env,
+                              const char* utf8name,
+                              const size_t props_count,
+                              const napi_property_descriptor* props,
+                              void* data = nullptr);
+
+  using StaticVoidMethodCallbackData =
+      MethodCallbackData<T, StaticVoidMethodCallback>;
+  using StaticMethodCallbackData = MethodCallbackData<T, StaticMethodCallback>;
+
+  using StaticAccessorCallbackData =
+      AccessorCallbackData<T, StaticGetterCallback, StaticSetterCallback>;
+
+  template <StaticSetterCallback method>
+  static napi_value WrappedMethod(napi_env env,
+                                  napi_callback_info info) NAPI_NOEXCEPT;
+
+  template <StaticSetterCallback setter>
+  struct StaticSetterTag {};
+
+  template <StaticSetterCallback setter>
+  static napi_callback WrapStaticSetter(StaticSetterTag<setter>) NAPI_NOEXCEPT {
+    return &This::WrappedMethod<setter>;
+  }
+  static napi_callback WrapStaticSetter(StaticSetterTag<nullptr>)
+      NAPI_NOEXCEPT {
+    return nullptr;
+  }
+
+  bool _construction_failed = true;
+  bool _finalized = false;
+};
+
+class HandleScope {
+ public:
+  HandleScope(napi_env env, napi_handle_scope scope);
+  explicit HandleScope(Napi::Env env);
+  ~HandleScope();
+
+  // Disallow copying to prevent double close of napi_handle_scope
+  NAPI_DISALLOW_ASSIGN_COPY(HandleScope)
+
+  operator napi_handle_scope() const;
+
+  Napi::Env Env() const;
+
+ private:
+  napi_env _env;
+  napi_handle_scope _scope;
+};
+
+class EscapableHandleScope {
+ public:
+  EscapableHandleScope(napi_env env, napi_escapable_handle_scope scope);
+  explicit EscapableHandleScope(Napi::Env env);
+  ~EscapableHandleScope();
+
+  // Disallow copying to prevent double close of napi_escapable_handle_scope
+  NAPI_DISALLOW_ASSIGN_COPY(EscapableHandleScope)
+
+  operator napi_escapable_handle_scope() const;
+
+  Napi::Env Env() const;
+  Value Escape(napi_value escapee);
+
+ private:
+  napi_env _env;
+  napi_escapable_handle_scope _scope;
+};
+
+#if (NAPI_VERSION > 2)
+class CallbackScope {
+ public:
+  CallbackScope(napi_env env, napi_callback_scope scope);
+  CallbackScope(napi_env env, napi_async_context context);
+  virtual ~CallbackScope();
+
+  // Disallow copying to prevent double close of napi_callback_scope
+  NAPI_DISALLOW_ASSIGN_COPY(CallbackScope)
+
+  operator napi_callback_scope() const;
+
+  Napi::Env Env() const;
+
+ private:
+  napi_env _env;
+  napi_callback_scope _scope;
+};
+#endif
+
+class AsyncContext {
+ public:
+  explicit AsyncContext(napi_env env, const char* resource_name);
+  explicit AsyncContext(napi_env env,
+                        const char* resource_name,
+                        const Object& resource);
+  virtual ~AsyncContext();
+
+  AsyncContext(AsyncContext&& other);
+  AsyncContext& operator=(AsyncContext&& other);
+  NAPI_DISALLOW_ASSIGN_COPY(AsyncContext)
+
+  operator napi_async_context() const;
+
+  Napi::Env Env() const;
+
+ private:
+  napi_env _env;
+  napi_async_context _context;
+};
+
+#if NAPI_HAS_THREADS
+class AsyncWorker {
+ public:
+  virtual ~AsyncWorker();
+
+  NAPI_DISALLOW_ASSIGN_COPY(AsyncWorker)
+
+  operator napi_async_work() const;
+
+  Napi::Env Env() const;
+
+  void Queue();
+  void Cancel();
+  void SuppressDestruct();
+
+  ObjectReference& Receiver();
+  FunctionReference& Callback();
+
+  virtual void OnExecute(Napi::Env env);
+  virtual void OnWorkComplete(Napi::Env env, napi_status status);
+
+ protected:
+  explicit AsyncWorker(const Function& callback);
+  explicit AsyncWorker(const Function& callback, const char* resource_name);
+  explicit AsyncWorker(const Function& callback,
+                       const char* resource_name,
+                       const Object& resource);
+  explicit AsyncWorker(const Object& receiver, const Function& callback);
+  explicit AsyncWorker(const Object& receiver,
+                       const Function& callback,
+                       const char* resource_name);
+  explicit AsyncWorker(const Object& receiver,
+                       const Function& callback,
+                       const char* resource_name,
+                       const Object& resource);
+
+  explicit AsyncWorker(Napi::Env env);
+  explicit AsyncWorker(Napi::Env env, const char* resource_name);
+  explicit AsyncWorker(Napi::Env env,
+                       const char* resource_name,
+                       const Object& resource);
+
+  virtual void Execute() = 0;
+  virtual void OnOK();
+  virtual void OnError(const Error& e);
+  virtual void Destroy();
+  virtual std::vector<napi_value> GetResult(Napi::Env env);
+
+  void SetError(const std::string& error);
+
+ private:
+  static inline void OnAsyncWorkExecute(napi_env env, void* asyncworker);
+  static inline void OnAsyncWorkComplete(napi_env env,
+                                         napi_status status,
+                                         void* asyncworker);
+
+  napi_env _env;
+  napi_async_work _work;
+  ObjectReference _receiver;
+  FunctionReference _callback;
+  std::string _error;
+  bool _suppress_destruct;
+};
+#endif  // NAPI_HAS_THREADS
+
+#if (NAPI_VERSION > 3 && NAPI_HAS_THREADS)
+class ThreadSafeFunction {
+ public:
+  // This API may only be called from the main thread.
+  template <typename ResourceString>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename ContextType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename Finalizer>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                Finalizer finalizeCallback);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename ContextType, typename Finalizer>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString,
+            typename ContextType,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename ContextType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename Finalizer>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                Finalizer finalizeCallback);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename ContextType, typename Finalizer>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString,
+            typename ContextType,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data);
+
+  ThreadSafeFunction();
+  ThreadSafeFunction(napi_threadsafe_function tsFunctionValue);
+
+  operator napi_threadsafe_function() const;
+
+  // This API may be called from any thread.
+  napi_status BlockingCall() const;
+
+  // This API may be called from any thread.
+  template <typename Callback>
+  napi_status BlockingCall(Callback callback) const;
+
+  // This API may be called from any thread.
+  template <typename DataType, typename Callback>
+  napi_status BlockingCall(DataType* data, Callback callback) const;
+
+  // This API may be called from any thread.
+  napi_status NonBlockingCall() const;
+
+  // This API may be called from any thread.
+  template <typename Callback>
+  napi_status NonBlockingCall(Callback callback) const;
+
+  // This API may be called from any thread.
+  template <typename DataType, typename Callback>
+  napi_status NonBlockingCall(DataType* data, Callback callback) const;
+
+  // This API may only be called from the main thread.
+  void Ref(napi_env env) const;
+
+  // This API may only be called from the main thread.
+  void Unref(napi_env env) const;
+
+  // This API may be called from any thread.
+  napi_status Acquire() const;
+
+  // This API may be called from any thread.
+  napi_status Release() const;
+
+  // This API may be called from any thread.
+  napi_status Abort() const;
+
+  struct ConvertibleContext {
+    template <class T>
+    operator T*() {
+      return static_cast<T*>(context);
+    }
+    void* context;
+  };
+
+  // This API may be called from any thread.
+  ConvertibleContext GetContext() const;
+
+ private:
+  using CallbackWrapper = std::function<void(Napi::Env, Napi::Function)>;
+
+  template <typename ResourceString,
+            typename ContextType,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data,
+                                napi_finalize wrapper);
+
+  napi_status CallInternal(CallbackWrapper* callbackWrapper,
+                           napi_threadsafe_function_call_mode mode) const;
+
+  static void CallJS(napi_env env,
+                     napi_value jsCallback,
+                     void* context,
+                     void* data);
+
+  napi_threadsafe_function _tsfn;
+};
+
+// A TypedThreadSafeFunction by default has no context (nullptr) and can
+// accept any type (void) to its CallJs.
+template <typename ContextType = std::nullptr_t,
+          typename DataType = void,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*) =
+              nullptr>
+class TypedThreadSafeFunction {
+ public:
+  // This API may only be called from the main thread.
+  // Helper function that returns nullptr if running Node-API 5+, otherwise a
+  // non-empty, no-op Function. This provides the ability to specify at
+  // compile-time a callback parameter to `New` that safely does no action
+  // when targeting _any_ Node-API version.
+#if NAPI_VERSION > 4
+  static std::nullptr_t EmptyFunctionFactory(Napi::Env env);
+#else
+  static Napi::Function EmptyFunctionFactory(Napi::Env env);
+#endif
+  static Napi::Function FunctionOrEmpty(Napi::Env env,
+                                        Napi::Function& callback);
+
+#if NAPI_VERSION > 4
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [missing] Resource [missing] Finalizer [missing]
+  template <typename ResourceString>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [missing] Resource [passed] Finalizer [missing]
+  template <typename ResourceString>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [missing] Resource [missing] Finalizer [passed]
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType = void>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [missing] Resource [passed] Finalizer [passed]
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType = void>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data = nullptr);
+#endif
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [passed] Resource [missing] Finalizer [missing]
+  template <typename ResourceString>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Function& callback,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [passed] Resource [passed] Finalizer [missing]
+  template <typename ResourceString>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Function& callback,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [passed] Resource [missing] Finalizer [passed]
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType = void>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Function& callback,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [passed] Resource [passed] Finalizer [passed]
+  template <typename CallbackType,
+            typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      CallbackType callback,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data = nullptr);
+
+  TypedThreadSafeFunction();
+  TypedThreadSafeFunction(napi_threadsafe_function tsFunctionValue);
+
+  operator napi_threadsafe_function() const;
+
+  // This API may be called from any thread.
+  napi_status BlockingCall(DataType* data = nullptr) const;
+
+  // This API may be called from any thread.
+  napi_status NonBlockingCall(DataType* data = nullptr) const;
+
+  // This API may only be called from the main thread.
+  void Ref(napi_env env) const;
+
+  // This API may only be called from the main thread.
+  void Unref(napi_env env) const;
+
+  // This API may be called from any thread.
+  napi_status Acquire() const;
+
+  // This API may be called from any thread.
+  napi_status Release() const;
+
+  // This API may be called from any thread.
+  napi_status Abort() const;
+
+  // This API may be called from any thread.
+  ContextType* GetContext() const;
+
+ private:
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Function& callback,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data,
+      napi_finalize wrapper);
+
+  static void CallJsInternal(napi_env env,
+                             napi_value jsCallback,
+                             void* context,
+                             void* data);
+
+ protected:
+  napi_threadsafe_function _tsfn;
+};
+template <typename DataType>
+class AsyncProgressWorkerBase : public AsyncWorker {
+ public:
+  virtual void OnWorkProgress(DataType* data) = 0;
+  class ThreadSafeData {
+   public:
+    ThreadSafeData(AsyncProgressWorkerBase* asyncprogressworker, DataType* data)
+        : _asyncprogressworker(asyncprogressworker), _data(data) {}
+
+    AsyncProgressWorkerBase* asyncprogressworker() {
+      return _asyncprogressworker;
+    };
+    DataType* data() { return _data; };
+
+   private:
+    AsyncProgressWorkerBase* _asyncprogressworker;
+    DataType* _data;
+  };
+  void OnWorkComplete(Napi::Env env, napi_status status) override;
+
+ protected:
+  explicit AsyncProgressWorkerBase(const Object& receiver,
+                                   const Function& callback,
+                                   const char* resource_name,
+                                   const Object& resource,
+                                   size_t queue_size = 1);
+  virtual ~AsyncProgressWorkerBase();
+
+// Optional callback of Napi::ThreadSafeFunction only available after
+// NAPI_VERSION 4. Refs: https://github.com/nodejs/node/pull/27791
+#if NAPI_VERSION > 4
+  explicit AsyncProgressWorkerBase(Napi::Env env,
+                                   const char* resource_name,
+                                   const Object& resource,
+                                   size_t queue_size = 1);
+#endif
+
+  static inline void OnAsyncWorkProgress(Napi::Env env,
+                                         Napi::Function jsCallback,
+                                         void* data);
+
+  napi_status NonBlockingCall(DataType* data);
+
+ private:
+  ThreadSafeFunction _tsfn;
+  bool _work_completed = false;
+  napi_status _complete_status;
+  static inline void OnThreadSafeFunctionFinalize(
+      Napi::Env env, void* data, AsyncProgressWorkerBase* context);
+};
+
+template <class T>
+class AsyncProgressWorker : public AsyncProgressWorkerBase<void> {
+ public:
+  virtual ~AsyncProgressWorker();
+
+  class ExecutionProgress {
+    friend class AsyncProgressWorker;
+
+   public:
+    void Signal() const;
+    void Send(const T* data, size_t count) const;
+
+   private:
+    explicit ExecutionProgress(AsyncProgressWorker* worker) : _worker(worker) {}
+    AsyncProgressWorker* const _worker;
+  };
+
+  void OnWorkProgress(void*) override;
+
+ protected:
+  explicit AsyncProgressWorker(const Function& callback);
+  explicit AsyncProgressWorker(const Function& callback,
+                               const char* resource_name);
+  explicit AsyncProgressWorker(const Function& callback,
+                               const char* resource_name,
+                               const Object& resource);
+  explicit AsyncProgressWorker(const Object& receiver,
+                               const Function& callback);
+  explicit AsyncProgressWorker(const Object& receiver,
+                               const Function& callback,
+                               const char* resource_name);
+  explicit AsyncProgressWorker(const Object& receiver,
+                               const Function& callback,
+                               const char* resource_name,
+                               const Object& resource);
+
+// Optional callback of Napi::ThreadSafeFunction only available after
+// NAPI_VERSION 4. Refs: https://github.com/nodejs/node/pull/27791
+#if NAPI_VERSION > 4
+  explicit AsyncProgressWorker(Napi::Env env);
+  explicit AsyncProgressWorker(Napi::Env env, const char* resource_name);
+  explicit AsyncProgressWorker(Napi::Env env,
+                               const char* resource_name,
+                               const Object& resource);
+#endif
+  virtual void Execute(const ExecutionProgress& progress) = 0;
+  virtual void OnProgress(const T* data, size_t count) = 0;
+
+ private:
+  void Execute() override;
+  void Signal();
+  void SendProgress_(const T* data, size_t count);
+
+  std::mutex _mutex;
+  T* _asyncdata;
+  size_t _asyncsize;
+  bool _signaled;
+};
+
+template <class T>
+class AsyncProgressQueueWorker
+    : public AsyncProgressWorkerBase<std::pair<T*, size_t>> {
+ public:
+  virtual ~AsyncProgressQueueWorker(){};
+
+  class ExecutionProgress {
+    friend class AsyncProgressQueueWorker;
+
+   public:
+    void Signal() const;
+    void Send(const T* data, size_t count) const;
+
+   private:
+    explicit ExecutionProgress(AsyncProgressQueueWorker* worker)
+        : _worker(worker) {}
+    AsyncProgressQueueWorker* const _worker;
+  };
+
+  void OnWorkComplete(Napi::Env env, napi_status status) override;
+  void OnWorkProgress(std::pair<T*, size_t>*) override;
+
+ protected:
+  explicit AsyncProgressQueueWorker(const Function& callback);
+  explicit AsyncProgressQueueWorker(const Function& callback,
+                                    const char* resource_name);
+  explicit AsyncProgressQueueWorker(const Function& callback,
+                                    const char* resource_name,
+                                    const Object& resource);
+  explicit AsyncProgressQueueWorker(const Object& receiver,
+                                    const Function& callback);
+  explicit AsyncProgressQueueWorker(const Object& receiver,
+                                    const Function& callback,
+                                    const char* resource_name);
+  explicit AsyncProgressQueueWorker(const Object& receiver,
+                                    const Function& callback,
+                                    const char* resource_name,
+                                    const Object& resource);
+
+// Optional callback of Napi::ThreadSafeFunction only available after
+// NAPI_VERSION 4. Refs: https://github.com/nodejs/node/pull/27791
+#if NAPI_VERSION > 4
+  explicit AsyncProgressQueueWorker(Napi::Env env);
+  explicit AsyncProgressQueueWorker(Napi::Env env, const char* resource_name);
+  explicit AsyncProgressQueueWorker(Napi::Env env,
+                                    const char* resource_name,
+                                    const Object& resource);
+#endif
+  virtual void Execute(const ExecutionProgress& progress) = 0;
+  virtual void OnProgress(const T* data, size_t count) = 0;
+
+ private:
+  void Execute() override;
+  void Signal() const;
+  void SendProgress_(const T* data, size_t count);
+};
+#endif  // NAPI_VERSION > 3 && NAPI_HAS_THREADS
+
+// Memory management.
+class MemoryManagement {
+ public:
+  static int64_t AdjustExternalMemory(BasicEnv env, int64_t change_in_bytes);
+};
+
+// Version management
+class VersionManagement {
+ public:
+  static uint32_t GetNapiVersion(BasicEnv env);
+  static const napi_node_version* GetNodeVersion(BasicEnv env);
+};
+
+#if NAPI_VERSION > 5
+template <typename T>
+class Addon : public InstanceWrap<T> {
+ public:
+  static inline Object Init(Env env, Object exports);
+  static T* Unwrap(Object wrapper);
+
+ protected:
+  using AddonProp = ClassPropertyDescriptor<T>;
+  void DefineAddon(Object exports,
+                   const std::initializer_list<AddonProp>& props);
+  Napi::Object DefineProperties(Object object,
+                                const std::initializer_list<AddonProp>& props);
+
+ private:
+  Object entry_point_;
+};
+#endif  // NAPI_VERSION > 5
+
+#ifdef NAPI_CPP_CUSTOM_NAMESPACE
+}  // namespace NAPI_CPP_CUSTOM_NAMESPACE
+#endif
+
+}  // namespace Napi
+
+// Inline implementations of all the above class methods are included here.
+#include "napi-inl.h"
+
+#endif  // SRC_NAPI_H_
diff --git a/server/node_modules/node-addon-api/node_addon_api.gyp b/server/node_modules/node-addon-api/node_addon_api.gyp
new file mode 100644
index 0000000..8c09926
--- /dev/null
+++ b/server/node_modules/node-addon-api/node_addon_api.gyp
@@ -0,0 +1,42 @@
+{
+  'targets': [
+    {
+      'target_name': 'node_addon_api',
+      'type': 'none',
+      'sources': [ 'napi.h', 'napi-inl.h' ],
+      'direct_dependent_settings': {
+        'include_dirs': [ '.' ],
+        'includes': ['noexcept.gypi'],
+      }
+    },
+    {
+      'target_name': 'node_addon_api_except',
+      'type': 'none',
+      'sources': [ 'napi.h', 'napi-inl.h' ],
+      'direct_dependent_settings': {
+        'include_dirs': [ '.' ],
+        'includes': ['except.gypi'],
+      }
+    },
+    {
+      'target_name': 'node_addon_api_except_all',
+      'type': 'none',
+      'sources': [ 'napi.h', 'napi-inl.h' ],
+      'direct_dependent_settings': {
+        'include_dirs': [ '.' ],
+        'includes': ['except.gypi'],
+        'defines': [ 'NODE_ADDON_API_CPP_EXCEPTIONS_ALL' ]
+      }
+    },
+    {
+      'target_name': 'node_addon_api_maybe',
+      'type': 'none',
+      'sources': [ 'napi.h', 'napi-inl.h' ],
+      'direct_dependent_settings': {
+        'include_dirs': [ '.' ],
+        'includes': ['noexcept.gypi'],
+        'defines': ['NODE_ADDON_API_ENABLE_MAYBE']
+      }
+    },
+  ]
+}
diff --git a/server/node_modules/node-addon-api/node_api.gyp b/server/node_modules/node-addon-api/node_api.gyp
new file mode 100644
index 0000000..4ff0ae7
--- /dev/null
+++ b/server/node_modules/node-addon-api/node_api.gyp
@@ -0,0 +1,9 @@
+{
+  'targets': [
+    {
+      'target_name': 'nothing',
+      'type': 'static_library',
+      'sources': [ 'nothing.c' ]
+    }
+  ]
+}
diff --git a/server/node_modules/node-addon-api/noexcept.gypi b/server/node_modules/node-addon-api/noexcept.gypi
new file mode 100644
index 0000000..83df4dd
--- /dev/null
+++ b/server/node_modules/node-addon-api/noexcept.gypi
@@ -0,0 +1,26 @@
+{
+  'defines': [ 'NODE_ADDON_API_DISABLE_CPP_EXCEPTIONS' ],
+  'cflags': [ '-fno-exceptions' ],
+  'cflags_cc': [ '-fno-exceptions' ],
+  'conditions': [
+    ["OS=='win'", {
+      # _HAS_EXCEPTIONS is already defined and set to 0 in common.gypi
+      #"defines": [
+      #  "_HAS_EXCEPTIONS=0"
+      #],
+      "msvs_settings": {
+        "VCCLCompilerTool": {
+          'ExceptionHandling': 0,
+          'EnablePREfast': 'true',
+        },
+      },
+    }],
+    ["OS=='mac'", {
+      'xcode_settings': {
+        'CLANG_CXX_LIBRARY': 'libc++',
+        'MACOSX_DEPLOYMENT_TARGET': '10.7',
+        'GCC_ENABLE_CPP_EXCEPTIONS': 'NO',
+      },
+    }],
+  ],
+}
diff --git a/server/node_modules/node-addon-api/nothing.c b/server/node_modules/node-addon-api/nothing.c
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/node-addon-api/package-support.json b/server/node_modules/node-addon-api/package-support.json
new file mode 100644
index 0000000..10d3607
--- /dev/null
+++ b/server/node_modules/node-addon-api/package-support.json
@@ -0,0 +1,21 @@
+{
+  "versions": [
+    {
+      "version": "*",
+      "target": {
+        "node": "active"
+      },
+      "response": {
+        "type": "time-permitting",
+        "paid": false,
+        "contact": {
+          "name": "node-addon-api team",
+          "url": "https://github.com/nodejs/node-addon-api/issues"
+        }
+      },
+      "backing": [ { "project": "https://github.com/nodejs" },
+                   { "foundation": "https://openjsf.org/" }
+      ]
+    }
+  ]
+}
diff --git a/server/node_modules/node-addon-api/package.json b/server/node_modules/node-addon-api/package.json
new file mode 100644
index 0000000..f04d661
--- /dev/null
+++ b/server/node_modules/node-addon-api/package.json
@@ -0,0 +1,480 @@
+{
+  "bugs": {
+    "url": "https://github.com/nodejs/node-addon-api/issues"
+  },
+  "contributors": [
+    {
+      "name": "Abhishek Kumar Singh",
+      "url": "https://github.com/abhi11210646"
+    },
+    {
+      "name": "Alba Mendez",
+      "url": "https://github.com/jmendeth"
+    },
+    {
+      "name": "Alexander Floh",
+      "url": "https://github.com/alexanderfloh"
+    },
+    {
+      "name": "Ammar Faizi",
+      "url": "https://github.com/ammarfaizi2"
+    },
+    {
+      "name": "András Timár, Dr",
+      "url": "https://github.com/timarandras"
+    },
+    {
+      "name": "Andrew Petersen",
+      "url": "https://github.com/kirbysayshi"
+    },
+    {
+      "name": "Anisha Rohra",
+      "url": "https://github.com/anisha-rohra"
+    },
+    {
+      "name": "Anna Henningsen",
+      "url": "https://github.com/addaleax"
+    },
+    {
+      "name": "Arnaud Botella",
+      "url": "https://github.com/BotellaA"
+    },
+    {
+      "name": "Arunesh Chandra",
+      "url": "https://github.com/aruneshchandra"
+    },
+    {
+      "name": "Azlan Mukhtar",
+      "url": "https://github.com/azlan"
+    },
+    {
+      "name": "Ben Berman",
+      "url": "https://github.com/rivertam"
+    },
+    {
+      "name": "Benjamin Byholm",
+      "url": "https://github.com/kkoopa"
+    },
+    {
+      "name": "Bill Gallafent",
+      "url": "https://github.com/gallafent"
+    },
+    {
+      "name": "blagoev",
+      "url": "https://github.com/blagoev"
+    },
+    {
+      "name": "Bruce A. MacNaughton",
+      "url": "https://github.com/bmacnaughton"
+    },
+    {
+      "name": "Cory Mickelson",
+      "url": "https://github.com/corymickelson"
+    },
+    {
+      "name": "Daniel Bevenius",
+      "url": "https://github.com/danbev"
+    },
+    {
+      "name": "Dante Calderón",
+      "url": "https://github.com/dantehemerson"
+    },
+    {
+      "name": "Darshan Sen",
+      "url": "https://github.com/RaisinTen"
+    },
+    {
+      "name": "David Halls",
+      "url": "https://github.com/davedoesdev"
+    },
+    {
+      "name": "Deepak Rajamohan",
+      "url": "https://github.com/deepakrkris"
+    },
+    {
+      "name": "Dmitry Ashkadov",
+      "url": "https://github.com/dmitryash"
+    },
+    {
+      "name": "Dongjin Na",
+      "url": "https://github.com/nadongguri"
+    },
+    {
+      "name": "Doni Rubiagatra",
+      "url": "https://github.com/rubiagatra"
+    },
+    {
+      "name": "Eric Bickle",
+      "url": "https://github.com/ebickle"
+    },
+    {
+      "name": "extremeheat",
+      "url": "https://github.com/extremeheat"
+    },
+    {
+      "name": "Feng Yu",
+      "url": "https://github.com/F3n67u"
+    },
+    {
+      "name": "Ferdinand Holzer",
+      "url": "https://github.com/fholzer"
+    },
+    {
+      "name": "Gabriel Schulhof",
+      "url": "https://github.com/gabrielschulhof"
+    },
+    {
+      "name": "Guenter Sandner",
+      "url": "https://github.com/gms1"
+    },
+    {
+      "name": "Gus Caplan",
+      "url": "https://github.com/devsnek"
+    },
+    {
+      "name": "Helio Frota",
+      "url": "https://github.com/helio-frota"
+    },
+    {
+      "name": "Hitesh Kanwathirtha",
+      "url": "https://github.com/digitalinfinity"
+    },
+    {
+      "name": "ikokostya",
+      "url": "https://github.com/ikokostya"
+    },
+    {
+      "name": "Jack Xia",
+      "url": "https://github.com/JckXia"
+    },
+    {
+      "name": "Jake Barnes",
+      "url": "https://github.com/DuBistKomisch"
+    },
+    {
+      "name": "Jake Yoon",
+      "url": "https://github.com/yjaeseok"
+    },
+    {
+      "name": "Jason Ginchereau",
+      "url": "https://github.com/jasongin"
+    },
+    {
+      "name": "Jenny",
+      "url": "https://github.com/egg-bread"
+    },
+    {
+      "name": "Jeroen Janssen",
+      "url": "https://github.com/japj"
+    },
+    {
+      "name": "Jim Schlight",
+      "url": "https://github.com/jschlight"
+    },
+    {
+      "name": "Jinho Bang",
+      "url": "https://github.com/romandev"
+    },
+    {
+      "name": "José Expósito",
+      "url": "https://github.com/JoseExposito"
+    },
+    {
+      "name": "joshgarde",
+      "url": "https://github.com/joshgarde"
+    },
+    {
+      "name": "Julian Mesa",
+      "url": "https://github.com/julianmesa-gitkraken"
+    },
+    {
+      "name": "Kasumi Hanazuki",
+      "url": "https://github.com/hanazuki"
+    },
+    {
+      "name": "Kelvin",
+      "url": "https://github.com/kelvinhammond"
+    },
+    {
+      "name": "Kevin Eady",
+      "url": "https://github.com/KevinEady"
+    },
+    {
+      "name": "Kévin VOYER",
+      "url": "https://github.com/kecsou"
+    },
+    {
+      "name": "kidneysolo",
+      "url": "https://github.com/kidneysolo"
+    },
+    {
+      "name": "Koki Nishihara",
+      "url": "https://github.com/Nishikoh"
+    },
+    {
+      "name": "Konstantin Tarkus",
+      "url": "https://github.com/koistya"
+    },
+    {
+      "name": "Kyle Farnung",
+      "url": "https://github.com/kfarnung"
+    },
+    {
+      "name": "Kyle Kovacs",
+      "url": "https://github.com/nullromo"
+    },
+    {
+      "name": "legendecas",
+      "url": "https://github.com/legendecas"
+    },
+    {
+      "name": "LongYinan",
+      "url": "https://github.com/Brooooooklyn"
+    },
+    {
+      "name": "Lovell Fuller",
+      "url": "https://github.com/lovell"
+    },
+    {
+      "name": "Luciano Martorella",
+      "url": "https://github.com/lmartorella"
+    },
+    {
+      "name": "mastergberry",
+      "url": "https://github.com/mastergberry"
+    },
+    {
+      "name": "Mathias Küsel",
+      "url": "https://github.com/mathiask88"
+    },
+    {
+      "name": "Mathias Stearn",
+      "url": "https://github.com/RedBeard0531"
+    },
+    {
+      "name": "Matteo Collina",
+      "url": "https://github.com/mcollina"
+    },
+    {
+      "name": "Michael Dawson",
+      "url": "https://github.com/mhdawson"
+    },
+    {
+      "name": "Michael Price",
+      "url": "https://github.com/mikepricedev"
+    },
+    {
+      "name": "Michele Campus",
+      "url": "https://github.com/kYroL01"
+    },
+    {
+      "name": "Mikhail Cheshkov",
+      "url": "https://github.com/mcheshkov"
+    },
+    {
+      "name": "nempoBu4",
+      "url": "https://github.com/nempoBu4"
+    },
+    {
+      "name": "Nicola Del Gobbo",
+      "url": "https://github.com/NickNaso"
+    },
+    {
+      "name": "Nick Soggin",
+      "url": "https://github.com/iSkore"
+    },
+    {
+      "name": "Nikolai Vavilov",
+      "url": "https://github.com/seishun"
+    },
+    {
+      "name": "Nurbol Alpysbayev",
+      "url": "https://github.com/anurbol"
+    },
+    {
+      "name": "pacop",
+      "url": "https://github.com/pacop"
+    },
+    {
+      "name": "Peter Šándor",
+      "url": "https://github.com/petersandor"
+    },
+    {
+      "name": "Philipp Renoth",
+      "url": "https://github.com/DaAitch"
+    },
+    {
+      "name": "rgerd",
+      "url": "https://github.com/rgerd"
+    },
+    {
+      "name": "Richard Lau",
+      "url": "https://github.com/richardlau"
+    },
+    {
+      "name": "Rolf Timmermans",
+      "url": "https://github.com/rolftimmermans"
+    },
+    {
+      "name": "Ross Weir",
+      "url": "https://github.com/ross-weir"
+    },
+    {
+      "name": "Ryuichi Okumura",
+      "url": "https://github.com/okuryu"
+    },
+    {
+      "name": "Saint Gabriel",
+      "url": "https://github.com/chineduG"
+    },
+    {
+      "name": "Sampson Gao",
+      "url": "https://github.com/sampsongao"
+    },
+    {
+      "name": "Sam Roberts",
+      "url": "https://github.com/sam-github"
+    },
+    {
+      "name": "strager",
+      "url": "https://github.com/strager"
+    },
+    {
+      "name": "Taylor Woll",
+      "url": "https://github.com/boingoing"
+    },
+    {
+      "name": "Thomas Gentilhomme",
+      "url": "https://github.com/fraxken"
+    },
+    {
+      "name": "Tim Rach",
+      "url": "https://github.com/timrach"
+    },
+    {
+      "name": "Tobias Nießen",
+      "url": "https://github.com/tniessen"
+    },
+    {
+      "name": "todoroff",
+      "url": "https://github.com/todoroff"
+    },
+    {
+      "name": "Toyo Li",
+      "url": "https://github.com/toyobayashi"
+    },
+    {
+      "name": "Tux3",
+      "url": "https://github.com/tux3"
+    },
+    {
+      "name": "Vlad Velmisov",
+      "url": "https://github.com/Velmisov"
+    },
+    {
+      "name": "Vladimir Morozov",
+      "url": "https://github.com/vmoroz"
+    },
+    {
+      "name": "WenheLI",
+      "url": "https://github.com/WenheLI"
+    },
+    {
+      "name": "Xuguang Mei",
+      "url": "https://github.com/meixg"
+    },
+    {
+      "name": "Yohei Kishimoto",
+      "url": "https://github.com/morokosi"
+    },
+    {
+      "name": "Yulong Wang",
+      "url": "https://github.com/fs-eire"
+    },
+    {
+      "name": "Ziqiu Zhao",
+      "url": "https://github.com/ZzqiZQute"
+    },
+    {
+      "name": "Feng Yu",
+      "url": "https://github.com/F3n67u"
+    },
+    {
+      "name": "wanlu wang",
+      "url": "https://github.com/wanlu"
+    },
+    {
+      "name": "Caleb Hearon",
+      "url": "https://github.com/chearon"
+    },
+    {
+      "name": "Marx",
+      "url": "https://github.com/MarxJiao"
+    },
+    {
+      "name": "Ömer AKGÜL",
+      "url": "https://github.com/tuhalf"
+    }
+  ],
+  "description": "Node.js API (Node-API)",
+  "devDependencies": {
+    "benchmark": "^2.1.4",
+    "bindings": "^1.5.0",
+    "clang-format": "^1.4.0",
+    "eslint": "^9.13.0",
+    "fs-extra": "^11.1.1",
+    "neostandard": "^0.12.0",
+    "pre-commit": "^1.2.2",
+    "semver": "^7.6.0"
+  },
+  "directories": {},
+  "gypfile": false,
+  "homepage": "https://github.com/nodejs/node-addon-api",
+  "keywords": [
+    "n-api",
+    "napi",
+    "addon",
+    "native",
+    "bindings",
+    "c",
+    "c++",
+    "nan",
+    "node-addon-api"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "name": "node-addon-api",
+  "readme": "README.md",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/nodejs/node-addon-api.git"
+  },
+  "files": [
+    "*.{c,h,gyp,gypi}",
+    "package-support.json",
+    "tools/"
+  ],
+  "scripts": {
+    "prebenchmark": "node-gyp rebuild -C benchmark",
+    "benchmark": "node benchmark",
+    "create-coverage": "npm test --coverage",
+    "report-coverage-html": "rm -rf coverage-html && mkdir coverage-html && gcovr -e test --merge-mode-functions merge-use-line-max --html-nested ./coverage-html/index.html test",
+    "report-coverage-xml": "rm -rf coverage-xml && mkdir coverage-xml && gcovr -e test --merge-mode-functions merge-use-line-max --xml -o ./coverage-xml/coverage-cxx.xml test",
+    "pretest": "node-gyp rebuild -C test",
+    "test": "node test",
+    "test:debug": "node-gyp rebuild -C test --debug && NODE_API_BUILD_CONFIG=Debug node ./test/index.js",
+    "predev": "node-gyp rebuild -C test --debug",
+    "dev": "node test",
+    "predev:incremental": "node-gyp configure build -C test --debug",
+    "dev:incremental": "node test",
+    "doc": "doxygen doc/Doxyfile",
+    "lint": "eslint && node tools/clang-format",
+    "lint:fix": "eslint --fix && node tools/clang-format --fix"
+  },
+  "pre-commit": "lint",
+  "version": "8.5.0",
+  "support": true,
+  "engines": {
+    "node": "^18 || ^20 || >= 21"
+  }
+}
diff --git a/server/node_modules/node-addon-api/tools/README.md b/server/node_modules/node-addon-api/tools/README.md
new file mode 100644
index 0000000..6b80e94
--- /dev/null
+++ b/server/node_modules/node-addon-api/tools/README.md
@@ -0,0 +1,73 @@
+# Tools
+
+## clang-format
+
+The clang-format checking tools is designed to check changed lines of code compared to given git-refs.
+
+## Migration Script
+
+The migration tool is designed to reduce repetitive work in the migration process. However, the script is not aiming to convert every thing for you. There are usually some small fixes and major reconstruction required.
+
+### How To Use
+
+To run the conversion script, first make sure you have the latest `node-addon-api` in your `node_modules` directory.
+```
+npm install node-addon-api
+```
+
+Then run the script passing your project directory
+```
+node ./node_modules/node-addon-api/tools/conversion.js ./
+```
+
+After finish, recompile and debug things that are missed by the script.
+
+
+### Quick Fixes
+Here is the list of things that can be fixed easily.
+  1. Change your methods' return value to void if it doesn't return value to JavaScript.
+  2. Use `.` to access attribute or to invoke member function in Napi::Object instead of `->`.
+  3. `Napi::New(env, value);` to `Napi::[Type]::New(env, value);
+
+
+### Major Reconstructions
+The implementation of `Napi::ObjectWrap` is significantly different from NAN's. `Napi::ObjectWrap` takes a pointer to the wrapped object and creates a reference to the wrapped object inside ObjectWrap constructor. `Napi::ObjectWrap` also associates wrapped object's instance methods to Javascript module instead of static methods like NAN.
+
+So if you use Nan::ObjectWrap in your module, you will need to execute the following steps.
+
+  1. Convert your [ClassName]::New function to a constructor function that takes a `Napi::CallbackInfo`. Declare it as
+```
+[ClassName](const Napi::CallbackInfo& info);
+```
+and define it as
+```
+[ClassName]::[ClassName](const Napi::CallbackInfo& info) : Napi::ObjectWrap<[ClassName]>(info){
+  ...
+}
+```
+This way, the `Napi::ObjectWrap` constructor will be invoked after the object has been instantiated and `Napi::ObjectWrap` can use the `this` pointer to create a reference to the wrapped object.
+
+  2. Move your original constructor code into the new constructor. Delete your original constructor.
+  3. In your class initialization function, associate native methods in the following way.
+```
+Napi::FunctionReference constructor;
+
+void [ClassName]::Init(Napi::Env env, Napi::Object exports, Napi::Object module) {
+  Napi::HandleScope scope(env);
+  Napi::Function ctor = DefineClass(env, "Canvas", {
+    InstanceMethod<&[ClassName]::Func1>("Func1"),
+    InstanceMethod<&[ClassName]::Func2>("Func2"),
+    InstanceAccessor<&[ClassName]::ValueGetter>("Value"),
+    StaticMethod<&[ClassName]::StaticMethod>("MethodName"),
+    InstanceValue("Value", Napi::[Type]::New(env, value)),
+  });
+
+  constructor = Napi::Persistent(ctor);
+  constructor .SuppressDestruct();
+  exports.Set("[ClassName]", ctor);
+}
+```
+  4. In function where you need to Unwrap the ObjectWrap in NAN like `[ClassName]* native = Nan::ObjectWrap::Unwrap<[ClassName]>(info.This());`, use `this` pointer directly as the unwrapped object as each ObjectWrap instance is associated with a unique object instance.
+
+
+If you still find issues after following this guide, please leave us an issue describing your problem and we will try to resolve it.
diff --git a/server/node_modules/node-addon-api/tools/check-napi.js b/server/node_modules/node-addon-api/tools/check-napi.js
new file mode 100644
index 0000000..9199af3
--- /dev/null
+++ b/server/node_modules/node-addon-api/tools/check-napi.js
@@ -0,0 +1,99 @@
+'use strict';
+// Descend into a directory structure and, for each file matching *.node, output
+// based on the imports found in the file whether it's an N-API module or not.
+
+const fs = require('fs');
+const path = require('path');
+
+// Read the output of the command, break it into lines, and use the reducer to
+// decide whether the file is an N-API module or not.
+function checkFile (file, command, argv, reducer) {
+  const child = require('child_process').spawn(command, argv, {
+    stdio: ['inherit', 'pipe', 'inherit']
+  });
+  let leftover = '';
+  let isNapi;
+  child.stdout.on('data', (chunk) => {
+    if (isNapi === undefined) {
+      chunk = (leftover + chunk.toString()).split(/[\r\n]+/);
+      leftover = chunk.pop();
+      isNapi = chunk.reduce(reducer, isNapi);
+      if (isNapi !== undefined) {
+        child.kill();
+      }
+    }
+  });
+  child.on('close', (code, signal) => {
+    if ((code === null && signal !== null) || (code !== 0)) {
+      console.log(
+        command + ' exited with code: ' + code + ' and signal: ' + signal);
+    } else {
+      // Green if it's a N-API module, red otherwise.
+      console.log(
+        '\x1b[' + (isNapi ? '42' : '41') + 'm' +
+          (isNapi ? '    N-API' : 'Not N-API') +
+          '\x1b[0m: ' + file);
+    }
+  });
+}
+
+// Use nm -a to list symbols.
+function checkFileUNIX (file) {
+  checkFile(file, 'nm', ['-a', file], (soFar, line) => {
+    if (soFar === undefined) {
+      line = line.match(/([0-9a-f]*)? ([a-zA-Z]) (.*$)/);
+      if (line[2] === 'U') {
+        if (/^napi/.test(line[3])) {
+          soFar = true;
+        }
+      }
+    }
+    return soFar;
+  });
+}
+
+// Use dumpbin /imports to list symbols.
+function checkFileWin32 (file) {
+  checkFile(file, 'dumpbin', ['/imports', file], (soFar, line) => {
+    if (soFar === undefined) {
+      line = line.match(/([0-9a-f]*)? +([a-zA-Z0-9]) (.*$)/);
+      if (line && /^napi/.test(line[line.length - 1])) {
+        soFar = true;
+      }
+    }
+    return soFar;
+  });
+}
+
+// Descend into a directory structure and pass each file ending in '.node' to
+// one of the above checks, depending on the OS.
+function recurse (top) {
+  fs.readdir(top, (error, items) => {
+    if (error) {
+      throw new Error('error reading directory ' + top + ': ' + error);
+    }
+    items.forEach((item) => {
+      item = path.join(top, item);
+      fs.stat(item, ((item) => (error, stats) => {
+        if (error) {
+          throw new Error('error about ' + item + ': ' + error);
+        }
+        if (stats.isDirectory()) {
+          recurse(item);
+        } else if (/[.]node$/.test(item) &&
+            // Explicitly ignore files called 'nothing.node' because they are
+            // artefacts of node-addon-api having identified a version of
+            // Node.js that ships with a correct implementation of N-API.
+            path.basename(item) !== 'nothing.node') {
+          process.platform === 'win32'
+            ? checkFileWin32(item)
+            : checkFileUNIX(item);
+        }
+      })(item));
+    });
+  });
+}
+
+// Start with the directory given on the command line or the current directory
+// if nothing was given.
+recurse(process.argv.length > 3 ? process.argv[2] : '.');
diff --git a/server/node_modules/node-addon-api/tools/clang-format.js b/server/node_modules/node-addon-api/tools/clang-format.js
new file mode 100644
index 0000000..e4bb4f5
--- /dev/null
+++ b/server/node_modules/node-addon-api/tools/clang-format.js
@@ -0,0 +1,71 @@
+#!/usr/bin/env node
+
+const spawn = require('child_process').spawnSync;
+const path = require('path');
+
+const filesToCheck = ['*.h', '*.cc'];
+const FORMAT_START = process.env.FORMAT_START || 'main';
+
+function main (args) {
+  let fix = false;
+  while (args.length > 0) {
+    switch (args[0]) {
+      case '-f':
+      case '--fix':
+        fix = true;
+        break;
+      default:
+    }
+    args.shift();
+  }
+
+  const clangFormatPath = path.dirname(require.resolve('clang-format'));
+  const binary = process.platform === 'win32'
+    ? 'node_modules\\.bin\\clang-format.cmd'
+    : 'node_modules/.bin/clang-format';
+  const options = ['--binary=' + binary, '--style=file'];
+  if (fix) {
+    options.push(FORMAT_START);
+  } else {
+    options.push('--diff', FORMAT_START);
+  }
+
+  const gitClangFormatPath = path.join(clangFormatPath, 'bin/git-clang-format');
+  const result = spawn(
+    'python',
+    [gitClangFormatPath, ...options, '--', ...filesToCheck],
+    { encoding: 'utf-8' }
+  );
+
+  if (result.stderr) {
+    console.error('Error running git-clang-format:', result.stderr);
+    return 2;
+  }
+
+  const clangFormatOutput = result.stdout.trim();
+  // Bail fast if in fix mode.
+  if (fix) {
+    console.log(clangFormatOutput);
+    return 0;
+  }
+  // Detect if there is any complains from clang-format
+  if (
+    clangFormatOutput !== '' &&
+    clangFormatOutput !== 'no modified files to format' &&
+    clangFormatOutput !== 'clang-format did not modify any files'
+  ) {
+    console.error(clangFormatOutput);
+    const fixCmd = 'npm run lint:fix';
+    console.error(`
+      ERROR: please run "${fixCmd}" to format changes in your commit
+        Note that when running the command locally, please keep your local
+        main branch and working branch up to date with nodejs/node-addon-api
+        to exclude un-related complains.
+        Or you can run "env FORMAT_START=upstream/main ${fixCmd}".`);
+    return 1;
+  }
+}
+
+if (require.main === module) {
+  process.exitCode = main(process.argv.slice(2));
+}
diff --git a/server/node_modules/node-addon-api/tools/conversion.js b/server/node_modules/node-addon-api/tools/conversion.js
new file mode 100755
index 0000000..e92a03a
--- /dev/null
+++ b/server/node_modules/node-addon-api/tools/conversion.js
@@ -0,0 +1,301 @@
+#! /usr/bin/env node
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+const args = process.argv.slice(2);
+const dir = args[0];
+if (!dir) {
+  console.log('Usage: node ' + path.basename(__filename) + ' <target-dir>');
+  process.exit(1);
+}
+
+const NodeApiVersion = require('../').version;
+
+const disable = args[1];
+let ConfigFileOperations;
+if (disable !== '--disable' && dir !== '--disable') {
+  ConfigFileOperations = {
+    'package.json': [
+      [/([ ]*)"dependencies": {/g, '$1"dependencies": {\n$1  "node-addon-api": "' + NodeApiVersion + '",'],
+      [/[ ]*"nan": *"[^"]+"(,|)[\n\r]/g, '']
+    ],
+    'binding.gyp': [
+      [/([ ]*)'include_dirs': \[/g, '$1\'include_dirs\': [\n$1  \'<!(node -p "require(\\\'node-addon-api\\\').include_dir")\','],
+      [/([ ]*)"include_dirs": \[/g, '$1"include_dirs": [\n$1  "<!(node -p \\"require(\'node-addon-api\').include_dir\\")",'],
+      [/[ ]*("|')<!$node -e ("|'|\\"|\\')require\(("|'|\\"|\\')nan("|'|\\"|\\')$("|'|\\"|\\')\)("|')(,|)[\r\n]/g, ''],
+      [/([ ]*)("|')target_name("|'): ("|')(.+?)("|'),/g, '$1$2target_name$2: $4$5$6,\n      $2cflags!$2: [ $2-fno-exceptions$2 ],\n      $2cflags_cc!$2: [ $2-fno-exceptions$2 ],\n      $2xcode_settings$2: { $2GCC_ENABLE_CPP_EXCEPTIONS$2: $2YES$2,\n        $2CLANG_CXX_LIBRARY$2: $2libc++$2,\n        $2MACOSX_DEPLOYMENT_TARGET$2: $210.7$2,\n      },\n      $2msvs_settings$2: {\n        $2VCCLCompilerTool$2: { $2ExceptionHandling$2: 1 },\n      },']
+    ]
+  };
+} else {
+  ConfigFileOperations = {
+    'package.json': [
+      [/([ ]*)"dependencies": {/g, '$1"dependencies": {\n$1  "node-addon-api": "' + NodeApiVersion + '",'],
+      [/[ ]*"nan": *"[^"]+"(,|)[\n\r]/g, '']
+    ],
+    'binding.gyp': [
+      [/([ ]*)'include_dirs': \[/g, '$1\'include_dirs\': [\n$1  \'<!(node -p "require(\\\'node-addon-api\\\').include_dir")\','],
+      [/([ ]*)"include_dirs": \[/g, '$1"include_dirs": [\n$1  "<!(node -p \'require(\\"node-addon-api\\").include_dir\')",'],
+      [/[ ]*("|')<!$node -e ("|'|\\"|\\')require\(("|'|\\"|\\')nan("|'|\\"|\\')$("|'|\\"|\\')\)("|')(,|)[\r\n]/g, ''],
+      [/([ ]*)("|')target_name("|'): ("|')(.+?)("|'),/g, '$1$2target_name$2: $4$5$6,\n      $2cflags!$2: [ $2-fno-exceptions$2 ],\n      $2cflags_cc!$2: [ $2-fno-exceptions$2 ],\n      $2defines$2: [ $2NAPI_DISABLE_CPP_EXCEPTIONS$2 ],\n      $2conditions$2: [\n        [\'OS=="win"\', { $2defines$2: [ $2_HAS_EXCEPTIONS=1$2 ] }]\n      ]']
+    ]
+  };
+}
+
+const SourceFileOperations = [
+  [/Nan::SetMethod$target,[\s]*"(.*)"[\s]*,[\s]*([^)]+)$/g, 'exports.Set(Napi::String::New(env, "$1"), Napi::Function::New(env, $2))'],
+
+  [/v8::Local<v8::FunctionTemplate>\s+(\w+)\s*=\s*Nan::New<FunctionTemplate>$[\w\d:]+$;(?:\w+->Reset$\1$)?\s+\1->SetClassName$Nan::String::New\("(\w+)"$\);/g, 'Napi::Function $1 = DefineClass(env, "$2", {'],
+  [/Local<FunctionTemplate>\s+(\w+)\s*=\s*Nan::New<FunctionTemplate>$[\w\d:]+$;\s+(\w+)\.Reset$(\1)$;\s+\1->SetClassName$(Nan::String::New|Nan::New<(v8::)*String>)\("(.+?)"$\);/g, 'Napi::Function $1 = DefineClass(env, "$6", {'],
+  [/Local<FunctionTemplate>\s+(\w+)\s*=\s*Nan::New<FunctionTemplate>$[\w\d:]+$;(?:\w+->Reset$\1$)?\s+\1->SetClassName$Nan::String::New\("(\w+)"$\);/g, 'Napi::Function $1 = DefineClass(env, "$2", {'],
+  [/Nan::New<v8::FunctionTemplate>$([\w\d:]+)$->GetFunction/g, 'Napi::Function::New(env, $1)'],
+  [/Nan::New<FunctionTemplate>$([\w\d:]+)$->GetFunction()/g, 'Napi::Function::New(env, $1);'],
+  [/Nan::New<v8::FunctionTemplate>$([\w\d:]+)$/g, 'Napi::Function::New(env, $1)'],
+  [/Nan::New<FunctionTemplate>$([\w\d:]+)$/g, 'Napi::Function::New(env, $1)'],
+
+  // FunctionTemplate to FunctionReference
+  [/Nan::Persistent<(v8::)*FunctionTemplate>/g, 'Napi::FunctionReference'],
+  [/Nan::Persistent<(v8::)*Function>/g, 'Napi::FunctionReference'],
+  [/v8::Local<v8::FunctionTemplate>/g, 'Napi::FunctionReference'],
+  [/Local<FunctionTemplate>/g, 'Napi::FunctionReference'],
+  [/v8::FunctionTemplate/g, 'Napi::FunctionReference'],
+  [/FunctionTemplate/g, 'Napi::FunctionReference'],
+
+  [/([ ]*)Nan::SetPrototypeMethod$\w+, "(\w+)", (\w+)$;/g, '$1InstanceMethod("$2", &$3),'],
+  [/([ ]*)(?:\w+\.Reset$\w+$;\s+)?$target$\.Set$"(\w+)",\s*Nan::GetFunction\((\w+)$\);/gm,
+    '});\n\n' +
+    '$1constructor = Napi::Persistent($3);\n' +
+    '$1constructor.SuppressDestruct();\n' +
+    '$1target.Set("$2", $3);'],
+
+  // TODO: Other attribute combinations
+  [/static_cast<PropertyAttribute>$ReadOnly\s*\|\s*DontDelete$/gm,
+    'static_cast<napi_property_attributes>(napi_enumerable | napi_configurable)'],
+
+  [/([\w\d:<>]+?)::Cast$(.+?)$/g, '$2.As<$1>()'],
+
+  [/\*Nan::Utf8String$([^)]+)$/g, '$1->As<Napi::String>().Utf8Value().c_str()'],
+  [/Nan::Utf8String +(\w+)$([^)]+)$/g, 'std::string $1 = $2.As<Napi::String>()'],
+  [/Nan::Utf8String/g, 'std::string'],
+
+  [/v8::String::Utf8Value (.+?)$(.+?)$/g, 'Napi::String $1(env, $2)'],
+  [/String::Utf8Value (.+?)$(.+?)$/g, 'Napi::String $1(env, $2)'],
+  [/\.length/g, '.Length()'],
+
+  [/Nan::MakeCallback$([^,]+),[\s\\]+([^,]+),/gm, '$2.MakeCallback($1,'],
+
+  [/class\s+(\w+)\s*:\s*public\s+Nan::ObjectWrap/g, 'class $1 : public Napi::ObjectWrap<$1>'],
+  [/(\w+)\(([^)]*)$\s*:\s*Nan::ObjectWrap\s*(,)?/gm, '$1($2) : Napi::ObjectWrap<$1>()$3'],
+
+  // HandleOKCallback to OnOK
+  [/HandleOKCallback/g, 'OnOK'],
+  // HandleErrorCallback to OnError
+  [/HandleErrorCallback/g, 'OnError'],
+
+  // ex. .As<Function>() to .As<Napi::Object>()
+  [/\.As<v8::(Value|Boolean|String|Number|Object|Array|Symbol|External|Function)>/g, '.As<Napi::$1>()'],
+  [/\.As<(Value|Boolean|String|Number|Object|Array|Symbol|External|Function)>/g, '.As<Napi::$1>()'],
+
+  // ex. Nan::New<Number>(info[0]) to Napi::Number::New(info[0])
+  [/Nan::New<(v8::)*Integer>$(.+?)$/g, 'Napi::Number::New(env, $2)'],
+  [/Nan::New$([0-9.]+)$/g, 'Napi::Number::New(env, $1)'],
+  [/Nan::New<(v8::)*String>$"(.+?)"$/g, 'Napi::String::New(env, "$2")'],
+  [/Nan::New$"(.+?)"$/g, 'Napi::String::New(env, "$1")'],
+  [/Nan::New<(v8::)*(.+?)>/g, 'Napi::$2::New(env)'],
+  [/Nan::New<(.+?)>/g, 'Napi::$1::New(env)'],
+  [/Nan::New<(v8::)*(.+?)>$/g, 'Napi::$2::New(env, '],
+  [/Nan::New<(.+?)>\(/g, 'Napi::$1::New(env, '],
+  [/Nan::NewBuffer\(/g, 'Napi::Buffer<char>::New(env, '],
+  // TODO: Properly handle this
+  [/Nan::New\(/g, 'Napi::New(env, '],
+
+  [/\.IsInt32\($/g, '.IsNumber()'],
+  [/->IsInt32/g, '.IsNumber()'],
+
+  [/(.+?)->BooleanValue/g, '$1.As<Napi::Boolean>().Value()'],
+  [/(.+?)->Int32Value/g, '$1.As<Napi::Number>().Int32Value()'],
+  [/(.+?)->Uint32Value/g, '$1.As<Napi::Number>().Uint32Value()'],
+  [/(.+?)->IntegerValue/g, '$1.As<Napi::Number>().Int64Value()'],
+  [/(.+?)->NumberValue/g, '$1.As<Napi::Number>().DoubleValue()'],
+
+  // ex. Nan::To<bool>(info[0]) to info[0].Value()
+  [/Nan::To<v8::(Boolean|String|Number|Object|Array|Symbol|Function)>$(.+?)$/g, '$2.To<Napi::$1>()'],
+  [/Nan::To<(Boolean|String|Number|Object|Array|Symbol|Function)>$(.+?)$/g, '$2.To<Napi::$1>()'],
+  // ex. Nan::To<bool>(info[0]) to info[0].As<Napi::Boolean>().Value()
+  [/Nan::To<bool>$(.+?)$/g, '$1.As<Napi::Boolean>().Value()'],
+  // ex. Nan::To<int>(info[0]) to info[0].As<Napi::Number>().Int32Value()
+  [/Nan::To<int>$(.+?)$/g, '$1.As<Napi::Number>().Int32Value()'],
+  // ex. Nan::To<int32_t>(info[0]) to info[0].As<Napi::Number>().Int32Value()
+  [/Nan::To<int32_t>$(.+?)$/g, '$1.As<Napi::Number>().Int32Value()'],
+  // ex. Nan::To<uint32_t>(info[0]) to info[0].As<Napi::Number>().Uint32Value()
+  [/Nan::To<uint32_t>$(.+?)$/g, '$1.As<Napi::Number>().Uint32Value()'],
+  // ex. Nan::To<int64_t>(info[0]) to info[0].As<Napi::Number>().Int64Value()
+  [/Nan::To<int64_t>$(.+?)$/g, '$1.As<Napi::Number>().Int64Value()'],
+  // ex. Nan::To<float>(info[0]) to info[0].As<Napi::Number>().FloatValue()
+  [/Nan::To<float>$(.+?)$/g, '$1.As<Napi::Number>().FloatValue()'],
+  // ex. Nan::To<double>(info[0]) to info[0].As<Napi::Number>().DoubleValue()
+  [/Nan::To<double>$(.+?)$/g, '$1.As<Napi::Number>().DoubleValue()'],
+
+  [/Nan::New$(\w+)$->HasInstance$(\w+)$/g, '$2.InstanceOf($1.Value())'],
+
+  [/Nan::Has$([^,]+),\s*/gm, '($1).Has('],
+  [/\.Has\([\s|\\]*Nan::New<(v8::)*String>\(([^)]+)$\)/gm, '.Has($1)'],
+  [/\.Has$[\s|\\]*Nan::New\(([^)]+)$\)/gm, '.Has($1)'],
+
+  [/Nan::Get$([^,]+),\s*/gm, '($1).Get('],
+  [/\.Get\([\s|\\]*Nan::New<(v8::)*String>\(([^)]+)$\)/gm, '.Get($1)'],
+  [/\.Get$[\s|\\]*Nan::New\(([^)]+)$\)/gm, '.Get($1)'],
+
+  [/Nan::Set$([^,]+),\s*/gm, '($1).Set('],
+  [/\.Set\([\s|\\]*Nan::New<(v8::)*String>\(([^)]+)$\s*,/gm, '.Set($1,'],
+  [/\.Set$[\s|\\]*Nan::New\(([^)]+)$\s*,/gm, '.Set($1,'],
+
+  // ex. node::Buffer::HasInstance(info[0]) to info[0].IsBuffer()
+  [/node::Buffer::HasInstance$(.+?)$/g, '$1.IsBuffer()'],
+  // ex. node::Buffer::Length(info[0]) to info[0].Length()
+  [/node::Buffer::Length$(.+?)$/g, '$1.As<Napi::Buffer<char>>().Length()'],
+  // ex. node::Buffer::Data(info[0]) to info[0].Data()
+  [/node::Buffer::Data$(.+?)$/g, '$1.As<Napi::Buffer<char>>().Data()'],
+  [/Nan::CopyBuffer$/g, 'Napi::Buffer::Copy(env, '],
+
+  // Nan::AsyncQueueWorker(worker)
+  [/Nan::AsyncQueueWorker\((.+)$;/g, '$1.Queue();'],
+  [/Nan::(Undefined|Null|True|False)/g, 'env.$1()'],
+
+  // Nan::ThrowError(error) to Napi::Error::New(env, error).ThrowAsJavaScriptException()
+  [/([ ]*)return Nan::Throw(\w*?)Error$(.+?)$;/g, '$1Napi::$2Error::New(env, $3).ThrowAsJavaScriptException();\n$1return env.Null();'],
+  [/Nan::Throw(\w*?)Error$(.+?)$;\n(\s*)return;/g, 'Napi::$1Error::New(env, $2).ThrowAsJavaScriptException();\n$3return env.Null();'],
+  [/Nan::Throw(\w*?)Error$(.+?)$;/g, 'Napi::$1Error::New(env, $2).ThrowAsJavaScriptException();\n'],
+  // Nan::RangeError(error) to Napi::RangeError::New(env, error)
+  [/Nan::(\w*?)Error$(.+)$/g, 'Napi::$1Error::New(env, $2)'],
+
+  [/Nan::Set$(.+?),\n* *(.+?),\n* *(.+?),\n* *(.+?)$/g, '$1.Set($2, $3, $4)'],
+
+  [/Nan::(Escapable)?HandleScope\s+(\w+)\s*;/g, 'Napi::$1HandleScope $2(env);'],
+  [/Nan::(Escapable)?HandleScope/g, 'Napi::$1HandleScope'],
+  [/Nan::ForceSet$([^,]+), ?/g, '$1->DefineProperty('],
+  [/\.ForceSet\(Napi::String::New\(env, "(\w+)"$,\s*?/g, '.DefineProperty("$1", '],
+  // [ /Nan::GetPropertyNames$([^,]+)$/, '$1->GetPropertyNames()' ],
+  [/Nan::Equals$([^,]+),/g, '$1.StrictEquals('],
+
+  [/(.+)->Set\(/g, '$1.Set('],
+
+  [/Nan::Callback/g, 'Napi::FunctionReference'],
+
+  [/Nan::Persistent<Object>/g, 'Napi::ObjectReference'],
+  [/Nan::ADDON_REGISTER_FUNCTION_ARGS_TYPE target/g, 'Napi::Env& env, Napi::Object& target'],
+
+  [/(\w+)\*\s+(\w+)\s*=\s*Nan::ObjectWrap::Unwrap<\w+>\(info\.This\($\);/g, '$1* $2 = this;'],
+  [/Nan::ObjectWrap::Unwrap<(\w+)>$(.*)$;/g, '$2.Unwrap<$1>();'],
+
+  [/Nan::NAN_METHOD_RETURN_TYPE/g, 'void'],
+  [/NAN_INLINE/g, 'inline'],
+
+  [/Nan::NAN_METHOD_ARGS_TYPE/g, 'const Napi::CallbackInfo&'],
+  [/NAN_METHOD$([\w\d:]+?)$/g, 'Napi::Value $1(const Napi::CallbackInfo& info)'],
+  [/static\s*NAN_GETTER$([\w\d:]+?)$/g, 'Napi::Value $1(const Napi::CallbackInfo& info)'],
+  [/NAN_GETTER$([\w\d:]+?)$/g, 'Napi::Value $1(const Napi::CallbackInfo& info)'],
+  [/static\s*NAN_SETTER$([\w\d:]+?)$/g, 'void $1(const Napi::CallbackInfo& info, const Napi::Value& value)'],
+  [/NAN_SETTER$([\w\d:]+?)$/g, 'void $1(const Napi::CallbackInfo& info, const Napi::Value& value)'],
+  [/void Init$(v8::)*Local<(v8::)*Object> exports$/g, 'Napi::Object Init(Napi::Env env, Napi::Object exports)'],
+  [/NAN_MODULE_INIT$([\w\d:]+?)$;/g, 'Napi::Object $1(Napi::Env env, Napi::Object exports);'],
+  [/NAN_MODULE_INIT$([\w\d:]+?)$/g, 'Napi::Object $1(Napi::Env env, Napi::Object exports)'],
+
+  [/::(Init(?:ialize)?)$target$/g, '::$1(env, target, module)'],
+  [/constructor_template/g, 'constructor'],
+
+  [/Nan::FunctionCallbackInfo<(v8::)?Value>[ ]*& [ ]*info\)[ ]*{\n*([ ]*)/gm, 'Napi::CallbackInfo& info) {\n$2Napi::Env env = info.Env();\n$2'],
+  [/Nan::FunctionCallbackInfo<(v8::)*Value>\s*&\s*info\);/g, 'Napi::CallbackInfo& info);'],
+  [/Nan::FunctionCallbackInfo<(v8::)*Value>\s*&/g, 'Napi::CallbackInfo&'],
+
+  [/Buffer::HasInstance$([^)]+)$/g, '$1.IsBuffer()'],
+
+  [/info\[(\d+)\]->/g, 'info[$1].'],
+  [/info\[([\w\d]+)\]->/g, 'info[$1].'],
+  [/info\.This->/g, 'info.This().'],
+  [/->Is(Object|String|Int32|Number)/g, '.Is$1()'],
+  [/info.GetReturnValue.SetUndefined/g, 'return env.Undefined()'],
+  [/info\.GetReturnValue\.Set$((\n|.)+?)$;/g, 'return $1;'],
+
+  // ex. Local<Value> to Napi::Value
+  [/v8::Local<v8::(Value|Boolean|String|Number|Object|Array|Symbol|External|Function)>/g, 'Napi::$1'],
+  [/Local<(Value|Boolean|String|Number|Object|Array|Symbol|External|Function)>/g, 'Napi::$1'],
+
+  // Declare an env in helper functions that take a Napi::Value
+  [/(\w+)$Napi::Value (\w+)(,\s*[^()]+)?$\s*{\n*([ ]*)/gm, '$1(Napi::Value $2$3) {\n$4Napi::Env env = $2.Env();\n$4'],
+
+  // delete #include <node.h> and/or <v8.h>
+  [/#include +(<|")(?:node|nan).h("|>)/g, '#include $1napi.h$2\n#include $1uv.h$2'],
+  // NODE_MODULE to NODE_API_MODULE
+  [/NODE_MODULE/g, 'NODE_API_MODULE'],
+  [/Nan::/g, 'Napi::'],
+  [/nan.h/g, 'napi.h'],
+
+  // delete .FromJust()
+  [/\.FromJust/g, ''],
+  // delete .ToLocalCheck()
+  [/\.ToLocalChecked/g, ''],
+  [/^.*->SetInternalFieldCount\(.*$/gm, ''],
+
+  // replace using node; and/or using v8; to using Napi;
+  [/using (node|v8);/g, 'using Napi;'],
+  [/using namespace (node|Nan|v8);/g, 'using namespace Napi;'],
+  // delete using v8::Local;
+  [/using v8::Local;\n/g, ''],
+  // replace using v8::XXX; with using Napi::XXX
+  [/using v8::([A-Za-z]+);/g, 'using Napi::$1;']
+
+];
+
+const paths = listFiles(dir);
+paths.forEach(function (dirEntry) {
+  const filename = dirEntry.split('\\').pop().split('/').pop();
+
+  // Check whether the file is a source file or a config file
+  // then execute function accordingly
+  const sourcePattern = /.+\.h|.+\.cc|.+\.cpp/;
+  if (sourcePattern.test(filename)) {
+    convertFile(dirEntry, SourceFileOperations);
+  } else if (ConfigFileOperations[filename] != null) {
+    convertFile(dirEntry, ConfigFileOperations[filename]);
+  }
+});
+
+function listFiles (dir, filelist) {
+  const files = fs.readdirSync(dir);
+  filelist = filelist || [];
+  files.forEach(function (file) {
+    if (file === 'node_modules') {
+      return;
+    }
+
+    if (fs.statSync(path.join(dir, file)).isDirectory()) {
+      filelist = listFiles(path.join(dir, file), filelist);
+    } else {
+      filelist.push(path.join(dir, file));
+    }
+  });
+  return filelist;
+}
+
+function convert (content, operations) {
+  for (let i = 0; i < operations.length; i++) {
+    const operation = operations[i];
+    content = content.replace(operation[0], operation[1]);
+  }
+  return content;
+}
+
+function convertFile (fileName, operations) {
+  fs.readFile(fileName, 'utf-8', function (err, file) {
+    if (err) throw err;
+
+    file = convert(file, operations);
+
+    fs.writeFile(fileName, file, function (err) {
+      if (err) throw err;
+    });
+  });
+}
diff --git a/server/node_modules/node-gyp-build/LICENSE b/server/node_modules/node-gyp-build/LICENSE
new file mode 100644
index 0000000..56fce08
--- /dev/null
+++ b/server/node_modules/node-gyp-build/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2017 Mathias Buus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/node-gyp-build/README.md b/server/node_modules/node-gyp-build/README.md
new file mode 100644
index 0000000..f712ca6
--- /dev/null
+++ b/server/node_modules/node-gyp-build/README.md
@@ -0,0 +1,58 @@
+# node-gyp-build
+
+> Build tool and bindings loader for [`node-gyp`][node-gyp] that supports prebuilds.
+
+```
+npm install node-gyp-build
+```
+
+[![Test](https://github.com/prebuild/node-gyp-build/actions/workflows/test.yml/badge.svg)](https://github.com/prebuild/node-gyp-build/actions/workflows/test.yml)
+
+Use together with [`prebuildify`][prebuildify] to easily support prebuilds for your native modules.
+
+## Usage
+
+> **Note.** Prebuild names have changed in [`prebuildify@3`][prebuildify] and `node-gyp-build@4`. Please see the documentation below.
+
+`node-gyp-build` works similar to [`node-gyp build`][node-gyp] except that it will check if a build or prebuild is present before rebuilding your project.
+
+It's main intended use is as an npm install script and bindings loader for native modules that bundle prebuilds using [`prebuildify`][prebuildify].
+
+First add `node-gyp-build` as an install script to your native project
+
+``` js
+{
+  ...
+  "scripts": {
+    "install": "node-gyp-build"
+  }
+}
+```
+
+Then in your `index.js`, instead of using the [`bindings`](https://www.npmjs.com/package/bindings) module use `node-gyp-build` to load your binding.
+
+``` js
+var binding = require('node-gyp-build')(__dirname)
+```
+
+If you do these two things and bundle prebuilds with [`prebuildify`][prebuildify] your native module will work for most platforms
+without having to compile on install time AND will work in both node and electron without the need to recompile between usage.
+
+Users can override `node-gyp-build` and force compiling by doing `npm install --build-from-source`.
+
+Prebuilds will be attempted loaded from `MODULE_PATH/prebuilds/...` and then next `EXEC_PATH/prebuilds/...` (the latter allowing use with `zeit/pkg`)
+
+## Supported prebuild names
+
+If so desired you can bundle more specific flavors, for example `musl` builds to support Alpine, or targeting a numbered ARM architecture version.
+
+These prebuilds can be bundled in addition to generic prebuilds; `node-gyp-build` will try to find the most specific flavor first. Prebuild filenames are composed of _tags_. The runtime tag takes precedence, as does an `abi` tag over `napi`. For more details on tags, please see [`prebuildify`][prebuildify].
+
+Values for the `libc` and `armv` tags are auto-detected but can be overridden through the `LIBC` and `ARM_VERSION` environment variables, respectively.
+
+## License
+
+MIT
+
+[prebuildify]: https://github.com/prebuild/prebuildify
+[node-gyp]: https://www.npmjs.com/package/node-gyp
diff --git a/server/node_modules/node-gyp-build/SECURITY.md b/server/node_modules/node-gyp-build/SECURITY.md
new file mode 100644
index 0000000..da9c516
--- /dev/null
+++ b/server/node_modules/node-gyp-build/SECURITY.md
@@ -0,0 +1,5 @@
+## Security contact information
+
+To report a security vulnerability, please use the
+[Tidelift security contact](https://tidelift.com/security).
+Tidelift will coordinate the fix and disclosure.
diff --git a/server/node_modules/node-gyp-build/bin.js b/server/node_modules/node-gyp-build/bin.js
new file mode 100755
index 0000000..c778e0a
--- /dev/null
+++ b/server/node_modules/node-gyp-build/bin.js
@@ -0,0 +1,84 @@
+#!/usr/bin/env node
+
+var proc = require('child_process')
+var os = require('os')
+var path = require('path')
+
+if (!buildFromSource()) {
+  proc.exec('node-gyp-build-test', function (err, stdout, stderr) {
+    if (err) {
+      if (verbose()) console.error(stderr)
+      preinstall()
+    }
+  })
+} else {
+  preinstall()
+}
+
+function build () {
+  var win32 = os.platform() === 'win32'
+  var shell = win32
+  var args = [win32 ? 'node-gyp.cmd' : 'node-gyp', 'rebuild']
+
+  try {
+    var pkg = require('node-gyp/package.json')
+    args = [
+      process.execPath,
+      path.join(require.resolve('node-gyp/package.json'), '..', typeof pkg.bin === 'string' ? pkg.bin : pkg.bin['node-gyp']),
+      'rebuild'
+    ]
+    shell = false
+  } catch (_) {}
+
+  proc.spawn(args[0], args.slice(1), { stdio: 'inherit', shell, windowsHide: true }).on('exit', function (code) {
+    if (code || !process.argv[3]) process.exit(code)
+    exec(process.argv[3]).on('exit', function (code) {
+      process.exit(code)
+    })
+  })
+}
+
+function preinstall () {
+  if (!process.argv[2]) return build()
+  exec(process.argv[2]).on('exit', function (code) {
+    if (code) process.exit(code)
+    build()
+  })
+}
+
+function exec (cmd) {
+  if (process.platform !== 'win32') {
+    var shell = os.platform() === 'android' ? 'sh' : true
+    return proc.spawn(cmd, [], {
+      shell,
+      stdio: 'inherit'
+    })
+  }
+
+  return proc.spawn(cmd, [], {
+    windowsVerbatimArguments: true,
+    stdio: 'inherit',
+    shell: true,
+    windowsHide: true
+  })
+}
+
+function buildFromSource () {
+  return hasFlag('--build-from-source') || process.env.npm_config_build_from_source === 'true'
+}
+
+function verbose () {
+  return hasFlag('--verbose') || process.env.npm_config_loglevel === 'verbose'
+}
+
+// TODO (next major): remove in favor of env.npm_config_* which works since npm
+// 0.1.8 while npm_config_argv will stop working in npm 7. See npm/rfcs#90
+function hasFlag (flag) {
+  if (!process.env.npm_config_argv) return false
+
+  try {
+    return JSON.parse(process.env.npm_config_argv).original.indexOf(flag) !== -1
+  } catch (_) {
+    return false
+  }
+}
diff --git a/server/node_modules/node-gyp-build/build-test.js b/server/node_modules/node-gyp-build/build-test.js
new file mode 100755
index 0000000..b6622a5
--- /dev/null
+++ b/server/node_modules/node-gyp-build/build-test.js
@@ -0,0 +1,19 @@
+#!/usr/bin/env node
+
+process.env.NODE_ENV = 'test'
+
+var path = require('path')
+var test = null
+
+try {
+  var pkg = require(path.join(process.cwd(), 'package.json'))
+  if (pkg.name && process.env[pkg.name.toUpperCase().replace(/-/g, '_')]) {
+    process.exit(0)
+  }
+  test = pkg.prebuild.test
+} catch (err) {
+  //  do nothing
+}
+
+if (test) require(path.join(process.cwd(), test))
+else require('./')()
diff --git a/server/node_modules/node-gyp-build/index.js b/server/node_modules/node-gyp-build/index.js
new file mode 100644
index 0000000..07eb14f
--- /dev/null
+++ b/server/node_modules/node-gyp-build/index.js
@@ -0,0 +1,6 @@
+const runtimeRequire = typeof __webpack_require__ === 'function' ? __non_webpack_require__ : require // eslint-disable-line
+if (typeof runtimeRequire.addon === 'function') { // if the platform supports native resolving prefer that
+  module.exports = runtimeRequire.addon.bind(runtimeRequire)
+} else { // else use the runtime version here
+  module.exports = require('./node-gyp-build.js')
+}
diff --git a/server/node_modules/node-gyp-build/node-gyp-build.js b/server/node_modules/node-gyp-build/node-gyp-build.js
new file mode 100644
index 0000000..76b96e1
--- /dev/null
+++ b/server/node_modules/node-gyp-build/node-gyp-build.js
@@ -0,0 +1,207 @@
+var fs = require('fs')
+var path = require('path')
+var os = require('os')
+
+// Workaround to fix webpack's build warnings: 'the request of a dependency is an expression'
+var runtimeRequire = typeof __webpack_require__ === 'function' ? __non_webpack_require__ : require // eslint-disable-line
+
+var vars = (process.config && process.config.variables) || {}
+var prebuildsOnly = !!process.env.PREBUILDS_ONLY
+var abi = process.versions.modules // TODO: support old node where this is undef
+var runtime = isElectron() ? 'electron' : (isNwjs() ? 'node-webkit' : 'node')
+
+var arch = process.env.npm_config_arch || os.arch()
+var platform = process.env.npm_config_platform || os.platform()
+var libc = process.env.LIBC || (isAlpine(platform) ? 'musl' : 'glibc')
+var armv = process.env.ARM_VERSION || (arch === 'arm64' ? '8' : vars.arm_version) || ''
+var uv = (process.versions.uv || '').split('.')[0]
+
+module.exports = load
+
+function load (dir) {
+  return runtimeRequire(load.resolve(dir))
+}
+
+load.resolve = load.path = function (dir) {
+  dir = path.resolve(dir || '.')
+
+  try {
+    var name = runtimeRequire(path.join(dir, 'package.json')).name.toUpperCase().replace(/-/g, '_')
+    if (process.env[name + '_PREBUILD']) dir = process.env[name + '_PREBUILD']
+  } catch (err) {}
+
+  if (!prebuildsOnly) {
+    var release = getFirst(path.join(dir, 'build/Release'), matchBuild)
+    if (release) return release
+
+    var debug = getFirst(path.join(dir, 'build/Debug'), matchBuild)
+    if (debug) return debug
+  }
+
+  var prebuild = resolve(dir)
+  if (prebuild) return prebuild
+
+  var nearby = resolve(path.dirname(process.execPath))
+  if (nearby) return nearby
+
+  var target = [
+    'platform=' + platform,
+    'arch=' + arch,
+    'runtime=' + runtime,
+    'abi=' + abi,
+    'uv=' + uv,
+    armv ? 'armv=' + armv : '',
+    'libc=' + libc,
+    'node=' + process.versions.node,
+    process.versions.electron ? 'electron=' + process.versions.electron : '',
+    typeof __webpack_require__ === 'function' ? 'webpack=true' : '' // eslint-disable-line
+  ].filter(Boolean).join(' ')
+
+  throw new Error('No native build was found for ' + target + '\n    loaded from: ' + dir + '\n')
+
+  function resolve (dir) {
+    // Find matching "prebuilds/<platform>-<arch>" directory
+    var tuples = readdirSync(path.join(dir, 'prebuilds')).map(parseTuple)
+    var tuple = tuples.filter(matchTuple(platform, arch)).sort(compareTuples)[0]
+    if (!tuple) return
+
+    // Find most specific flavor first
+    var prebuilds = path.join(dir, 'prebuilds', tuple.name)
+    var parsed = readdirSync(prebuilds).map(parseTags)
+    var candidates = parsed.filter(matchTags(runtime, abi))
+    var winner = candidates.sort(compareTags(runtime))[0]
+    if (winner) return path.join(prebuilds, winner.file)
+  }
+}
+
+function readdirSync (dir) {
+  try {
+    return fs.readdirSync(dir)
+  } catch (err) {
+    return []
+  }
+}
+
+function getFirst (dir, filter) {
+  var files = readdirSync(dir).filter(filter)
+  return files[0] && path.join(dir, files[0])
+}
+
+function matchBuild (name) {
+  return /\.node$/.test(name)
+}
+
+function parseTuple (name) {
+  // Example: darwin-x64+arm64
+  var arr = name.split('-')
+  if (arr.length !== 2) return
+
+  var platform = arr[0]
+  var architectures = arr[1].split('+')
+
+  if (!platform) return
+  if (!architectures.length) return
+  if (!architectures.every(Boolean)) return
+
+  return { name, platform, architectures }
+}
+
+function matchTuple (platform, arch) {
+  return function (tuple) {
+    if (tuple == null) return false
+    if (tuple.platform !== platform) return false
+    return tuple.architectures.includes(arch)
+  }
+}
+
+function compareTuples (a, b) {
+  // Prefer single-arch prebuilds over multi-arch
+  return a.architectures.length - b.architectures.length
+}
+
+function parseTags (file) {
+  var arr = file.split('.')
+  var extension = arr.pop()
+  var tags = { file: file, specificity: 0 }
+
+  if (extension !== 'node') return
+
+  for (var i = 0; i < arr.length; i++) {
+    var tag = arr[i]
+
+    if (tag === 'node' || tag === 'electron' || tag === 'node-webkit') {
+      tags.runtime = tag
+    } else if (tag === 'napi') {
+      tags.napi = true
+    } else if (tag.slice(0, 3) === 'abi') {
+      tags.abi = tag.slice(3)
+    } else if (tag.slice(0, 2) === 'uv') {
+      tags.uv = tag.slice(2)
+    } else if (tag.slice(0, 4) === 'armv') {
+      tags.armv = tag.slice(4)
+    } else if (tag === 'glibc' || tag === 'musl') {
+      tags.libc = tag
+    } else {
+      continue
+    }
+
+    tags.specificity++
+  }
+
+  return tags
+}
+
+function matchTags (runtime, abi) {
+  return function (tags) {
+    if (tags == null) return false
+    if (tags.runtime && tags.runtime !== runtime && !runtimeAgnostic(tags)) return false
+    if (tags.abi && tags.abi !== abi && !tags.napi) return false
+    if (tags.uv && tags.uv !== uv) return false
+    if (tags.armv && tags.armv !== armv) return false
+    if (tags.libc && tags.libc !== libc) return false
+
+    return true
+  }
+}
+
+function runtimeAgnostic (tags) {
+  return tags.runtime === 'node' && tags.napi
+}
+
+function compareTags (runtime) {
+  // Precedence: non-agnostic runtime, abi over napi, then by specificity.
+  return function (a, b) {
+    if (a.runtime !== b.runtime) {
+      return a.runtime === runtime ? -1 : 1
+    } else if (a.abi !== b.abi) {
+      return a.abi ? -1 : 1
+    } else if (a.specificity !== b.specificity) {
+      return a.specificity > b.specificity ? -1 : 1
+    } else {
+      return 0
+    }
+  }
+}
+
+function isNwjs () {
+  return !!(process.versions && process.versions.nw)
+}
+
+function isElectron () {
+  if (process.versions && process.versions.electron) return true
+  if (process.env.ELECTRON_RUN_AS_NODE) return true
+  return typeof window !== 'undefined' && window.process && window.process.type === 'renderer'
+}
+
+function isAlpine (platform) {
+  return platform === 'linux' && fs.existsSync('/etc/alpine-release')
+}
+
+// Exposed for unit tests
+// TODO: move to lib
+load.parseTags = parseTags
+load.matchTags = matchTags
+load.compareTags = compareTags
+load.parseTuple = parseTuple
+load.matchTuple = matchTuple
+load.compareTuples = compareTuples
diff --git a/server/node_modules/node-gyp-build/optional.js b/server/node_modules/node-gyp-build/optional.js
new file mode 100755
index 0000000..8daa04a
--- /dev/null
+++ b/server/node_modules/node-gyp-build/optional.js
@@ -0,0 +1,7 @@
+#!/usr/bin/env node
+
+/*
+I am only useful as an install script to make node-gyp not compile for purely optional native deps
+*/
+
+process.exit(0)
diff --git a/server/node_modules/node-gyp-build/package.json b/server/node_modules/node-gyp-build/package.json
new file mode 100644
index 0000000..6f6f28b
--- /dev/null
+++ b/server/node_modules/node-gyp-build/package.json
@@ -0,0 +1,43 @@
+{
+  "name": "node-gyp-build",
+  "version": "4.8.4",
+  "description": "Build tool and bindings loader for node-gyp that supports prebuilds",
+  "main": "index.js",
+  "imports": {
+    "fs": {
+      "bare": "builtin:fs",
+      "default": "fs"
+    },
+    "path": {
+      "bare": "builtin:path",
+      "default": "path"
+    },
+    "os": {
+      "bare": "builtin:os",
+      "default": "os"
+    }
+  },
+  "devDependencies": {
+    "array-shuffle": "^1.0.1",
+    "standard": "^14.0.0",
+    "tape": "^5.0.0"
+  },
+  "scripts": {
+    "test": "standard && node test"
+  },
+  "bin": {
+    "node-gyp-build": "./bin.js",
+    "node-gyp-build-optional": "./optional.js",
+    "node-gyp-build-test": "./build-test.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/prebuild/node-gyp-build.git"
+  },
+  "author": "Mathias Buus (@mafintosh)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/prebuild/node-gyp-build/issues"
+  },
+  "homepage": "https://github.com/prebuild/node-gyp-build"
+}
diff --git a/server/node_modules/node-gyp/.github/ISSUE_TEMPLATE.md b/server/node_modules/node-gyp/.github/ISSUE_TEMPLATE.md
new file mode 100644
index 0000000..c6b213d
--- /dev/null
+++ b/server/node_modules/node-gyp/.github/ISSUE_TEMPLATE.md
@@ -0,0 +1,52 @@
+
+
+Please look thru your error log for the string `gyp info using node-gyp@` and if the version number is less than the [current release of node-gyp](https://github.com/nodejs/node-gyp/releases) then __please upgrade__ using the instructions at https://github.com/nodejs/node-gyp/blob/master/docs/Updating-npm-bundled-node-gyp.md and try your command again.
+
+Requests for help with [`node-sass` are very common](https://github.com/nodejs/node-gyp/issues?q=label%3A%22Node+Sass+--%3E+Dart+Sass%22). Please be aware that this package is deprecated, you should seek alternatives and avoid opening new issues about it here.
+
+* **Node Version**: 
+* **Platform**: 
+* **Compiler**: 
+* **Module**: 
+
+<details><summary>Verbose output (from npm or node-gyp):</summary>
+
+```
+Paste your log here, between the backticks. It can be:
+  - npm --verbose output,
+  - or contents of npm-debug.log,
+  - or output of node-gyp rebuild --verbose.
+Include the command you were trying to run.
+
+This should look like this:
+
+>npm --verbose
+npm info it worked if it ends with ok
+npm verb cli [
+npm verb cli   'C:\\...\\node\\13.9.0\\x64\\node.exe',
+npm verb cli   'C:\\...\\node\\13.9.0\\x64\\node_modules\\npm\\bin\\npm-cli.js',
+npm verb cli   '--verbose'
+npm verb cli ]
+npm info using npm@6.13.7
+npm info using node@v13.9.0
+
+Usage: npm <command>
+(...)
+```
+
+</details>
+
+
diff --git a/server/node_modules/node-gyp/.github/PULL_REQUEST_TEMPLATE.md b/server/node_modules/node-gyp/.github/PULL_REQUEST_TEMPLATE.md
new file mode 100644
index 0000000..bcc4bb1
--- /dev/null
+++ b/server/node_modules/node-gyp/.github/PULL_REQUEST_TEMPLATE.md
@@ -0,0 +1,17 @@
+
+
+##### Checklist
+
+
+- [ ] `npm install && npm test` passes
+- [ ] tests are included 
+- [ ] documentation is changed or added
+- [ ] commit message follows [commit guidelines](https://github.com/googleapis/release-please#how-should-i-write-my-commits)
+
+##### Description of change
+
+
diff --git a/server/node_modules/node-gyp/.github/workflows/release-please.yml b/server/node_modules/node-gyp/.github/workflows/release-please.yml
new file mode 100644
index 0000000..7d3cf9d
--- /dev/null
+++ b/server/node_modules/node-gyp/.github/workflows/release-please.yml
@@ -0,0 +1,56 @@
+name: release-please
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  release-please:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: google-github-actions/release-please-action@v2
+        id: release
+        with:
+          package-name: node-gyp
+          release-type: node
+          changelog-types: >
+            [{"type":"feat","section":"Features","hidden":false},
+            {"type":"fix","section":"Bug Fixes","hidden":false},
+            {"type":"bin","section":"Core","hidden":false},
+            {"type":"gyp","section":"Core","hidden":false},
+            {"type":"lib","section":"Core","hidden":false},
+            {"type":"src","section":"Core","hidden":false},
+            {"type":"test","section":"Tests","hidden":false},
+            {"type":"build","section":"Core","hidden":false},
+            {"type":"clean","section":"Core","hidden":false},
+            {"type":"configure","section":"Core","hidden":false},
+            {"type":"install","section":"Core","hidden":false},
+            {"type":"list","section":"Core","hidden":false},
+            {"type":"rebuild","section":"Core","hidden":false},
+            {"type":"remove","section":"Core","hidden":false},
+            {"type":"deps","section":"Core","hidden":false},
+            {"type":"python","section":"Core","hidden":false},
+            {"type":"lin","section":"Core","hidden":false},
+            {"type":"linux","section":"Core","hidden":false},
+            {"type":"mac","section":"Core","hidden":false},
+            {"type":"macos","section":"Core","hidden":false},
+            {"type":"win","section":"Core","hidden":false},
+            {"type":"windows","section":"Core","hidden":false},
+            {"type":"zos","section":"Core","hidden":false},
+            {"type":"doc","section":"Doc","hidden":false},
+            {"type":"docs","section":"Doc","hidden":false},
+            {"type":"readme","section":"Doc","hidden":false},
+            {"type":"chore","section":"Miscellaneous","hidden":false},
+            {"type":"refactor","section":"Miscellaneous","hidden":false},
+            {"type":"ci","section":"Miscellaneous","hidden":false},
+            {"type":"meta","section":"Miscellaneous","hidden":false}]
+
+          # Standard Conventional Commits: `feat` and `fix`
+          # node-gyp subdirectories: `bin`, `gyp`, `lib`, `src`, `test`
+          # node-gyp subcommands: `build`, `clean`, `configure`, `install`, `list`, `rebuild`, `remove`
+          # Core abstract category: `deps`
+          # Languages/platforms: `python`, `lin`, `linux`, `mac`, `macos`, `win`, `window`, `zos`
+          # Documentation: `doc`, `docs`, `readme`
+          # Standard Conventional Commits: `chore` (under "Miscellaneous")
+          # Miscellaneous abstract categories: `refactor`, `ci`, `meta`
diff --git a/server/node_modules/node-gyp/.github/workflows/tests.yml b/server/node_modules/node-gyp/.github/workflows/tests.yml
new file mode 100644
index 0000000..f7c9b97
--- /dev/null
+++ b/server/node_modules/node-gyp/.github/workflows/tests.yml
@@ -0,0 +1,45 @@
+# TODO: Line 43, enable pytest --doctest-modules
+
+name: Tests
+on: [push, pull_request]
+jobs:
+  Tests:
+    strategy:
+      fail-fast: false
+      max-parallel: 15
+      matrix:
+        node: [12.x, 14.x, 16.x]
+        python: ["3.6", "3.8", "3.10"]
+        os: [macos-latest, ubuntu-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v2
+      - name: Use Node.js ${{ matrix.node }}
+        uses: actions/setup-node@v2
+        with:
+          node-version: ${{ matrix.node }}
+      - name: Use Python ${{ matrix.python }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python }}
+        env:
+          PYTHON_VERSION: ${{ matrix.python }}
+      - name: Install Dependencies
+        run: |
+          npm install --no-progress
+          pip install flake8 pytest
+      - name: Set Windows environment
+        if: matrix.os == 'windows-latest'
+        run: |
+          echo 'GYP_MSVS_VERSION=2015' >> $Env:GITHUB_ENV
+          echo 'GYP_MSVS_OVERRIDE_PATH=C:\\Dummy' >> $Env:GITHUB_ENV
+      - name: Lint Python
+        if: matrix.os == 'ubuntu-latest'
+        run: flake8 . --ignore=E203,W503  --max-complexity=101 --max-line-length=88 --show-source --statistics
+      - name: Run Python tests
+        run: python -m pytest
+      # - name: Run doctests with pytest
+      #   run: python -m pytest --doctest-modules
+      - name: Run Node tests
+        run: npm test
diff --git a/server/node_modules/node-gyp/.github/workflows/visual-studio.yml b/server/node_modules/node-gyp/.github/workflows/visual-studio.yml
new file mode 100644
index 0000000..6bb4574
--- /dev/null
+++ b/server/node_modules/node-gyp/.github/workflows/visual-studio.yml
@@ -0,0 +1,25 @@
+name: Tests on Windows
+on: [push, pull_request]
+jobs:
+  Tests:
+    strategy:
+      fail-fast: false
+      max-parallel: 15
+      matrix:
+        os: [windows-2022]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v2
+      - name: Install Dependencies
+        run: |
+          npm install --no-progress
+      - name: Set Windows environment
+        if: matrix.os == 'windows-latest'
+        run: |
+          echo 'GYP_MSVS_VERSION=2015' >> $Env:GITHUB_ENV
+          echo 'GYP_MSVS_OVERRIDE_PATH=C:\\Dummy' >> $Env:GITHUB_ENV
+      - name: Environment Information
+        run: npx envinfo
+      - name: Run Node tests
+        run: npm test
diff --git a/server/node_modules/node-gyp/CHANGELOG.md b/server/node_modules/node-gyp/CHANGELOG.md
new file mode 100644
index 0000000..1e54fd6
--- /dev/null
+++ b/server/node_modules/node-gyp/CHANGELOG.md
@@ -0,0 +1,687 @@
+# Changelog
+
+### [8.4.1](https://www.github.com/nodejs/node-gyp/compare/v8.4.0...v8.4.1) (2021-11-19)
+
+
+### Bug Fixes
+
+* windows command missing space ([#2553](https://www.github.com/nodejs/node-gyp/issues/2553)) ([cc37b88](https://www.github.com/nodejs/node-gyp/commit/cc37b880690706d3c5d04d5a68c76c392a0a23ed))
+
+
+### Doc
+
+* fix typo in powershell node-gyp update ([787cf7f](https://www.github.com/nodejs/node-gyp/commit/787cf7f8e5ddd5039e02b64ace6b7b15e06fe0a4))
+
+
+### Core
+
+* npmlog@6.0.0 ([8083f6b](https://www.github.com/nodejs/node-gyp/commit/8083f6b855bd7f3326af04c5f5269fc28d7f2508))
+
+## [8.4.0](https://www.github.com/nodejs/node-gyp/compare/v8.3.0...v8.4.0) (2021-11-05)
+
+
+### Features
+
+* build with config.gypi from node headers ([a27dc08](https://www.github.com/nodejs/node-gyp/commit/a27dc08696911c6d81e76cc228697243069103c1))
+* support vs2022 ([#2533](https://www.github.com/nodejs/node-gyp/issues/2533)) ([5a00387](https://www.github.com/nodejs/node-gyp/commit/5a00387e5f8018264a1822f6c4d5dbf425f21cf6))
+
+## [8.3.0](https://www.github.com/nodejs/node-gyp/compare/v8.2.0...v8.3.0) (2021-10-11)
+
+
+### Features
+
+* **gyp:** update gyp to v0.10.0 ([#2521](https://www.github.com/nodejs/node-gyp/issues/2521)) ([5585792](https://www.github.com/nodejs/node-gyp/commit/5585792922a97f0629f143c560efd74470eae87f))
+
+
+### Tests
+
+* Python 3.10 was release on Oct. 4th ([#2504](https://www.github.com/nodejs/node-gyp/issues/2504)) ([0a67dcd](https://www.github.com/nodejs/node-gyp/commit/0a67dcd1307f3560495219253241eafcbf4e2a69))
+
+
+### Miscellaneous
+
+* **deps:** bump make-fetch-happen from 8.0.14 to 9.1.0 ([b05b4fe](https://www.github.com/nodejs/node-gyp/commit/b05b4fe9891f718f40edf547e9b50e982826d48a))
+* refactor the creation of config.gypi file ([f2ad87f](https://www.github.com/nodejs/node-gyp/commit/f2ad87ff65f98ad66daa7225ad59d99b759a2b07))
+
+## [8.2.0](https://www.github.com/nodejs/node-gyp/compare/v8.1.0...v8.2.0) (2021-08-23)
+
+
+### Features
+
+* **gyp:** update gyp to v0.9.6 ([#2481](https://www.github.com/nodejs/node-gyp/issues/2481)) ([ed9a9ed](https://www.github.com/nodejs/node-gyp/commit/ed9a9ed653a17c84afa3c327161992d0da7d0cea))
+
+
+### Bug Fixes
+
+* add error arg back into catch block for older Node.js users ([5cde818](https://www.github.com/nodejs/node-gyp/commit/5cde818aac715477e9e9747966bb6b4c4ed070a8))
+* change default gyp update message ([#2420](https://www.github.com/nodejs/node-gyp/issues/2420)) ([cfd12ff](https://www.github.com/nodejs/node-gyp/commit/cfd12ff3bb0eb4525173413ef6a94b3cd8398cad))
+* doc how to update node-gyp independently from npm ([c8c0af7](https://www.github.com/nodejs/node-gyp/commit/c8c0af72e78141a02b5da4cd4d704838333a90bd))
+* missing spaces ([f0882b1](https://www.github.com/nodejs/node-gyp/commit/f0882b1264b2fa701adbc81a3be0b3cba80e333d))
+
+
+### Core
+
+* deep-copy process.config during configure ([#2368](https://www.github.com/nodejs/node-gyp/issues/2368)) ([5f1a06c](https://www.github.com/nodejs/node-gyp/commit/5f1a06c50f3b0c3d292f64948f85a004cfcc5c87))
+
+
+### Miscellaneous
+
+* **deps:** bump tar from 6.1.0 to 6.1.2 ([#2474](https://www.github.com/nodejs/node-gyp/issues/2474)) ([ec15a3e](https://www.github.com/nodejs/node-gyp/commit/ec15a3e5012004172713c11eebcc9d852d32d380))
+* fix typos discovered by codespell ([#2442](https://www.github.com/nodejs/node-gyp/issues/2442)) ([2d0ce55](https://www.github.com/nodejs/node-gyp/commit/2d0ce5595e232a3fc7c562cdf39efb77e2312cc1))
+* GitHub Actions Test on node: [12.x, 14.x, 16.x] ([#2439](https://www.github.com/nodejs/node-gyp/issues/2439)) ([b7bccdb](https://www.github.com/nodejs/node-gyp/commit/b7bccdb527d93b0bb0ce99713f083ce2985fe85c))
+
+
+### Doc
+
+* correct link to "binding.gyp files out in the wild" ([#2483](https://www.github.com/nodejs/node-gyp/issues/2483)) ([660dd7b](https://www.github.com/nodejs/node-gyp/commit/660dd7b2a822c184be8027b300e68be67b366772))
+* **wiki:** Add a link to the node-midi binding.gyp file. ([b354711](https://www.github.com/nodejs/node-gyp/commit/b3547115f6e356358138310e857c7f1ec627a8a7))
+* **wiki:** add bcrypt ([e199cfa](https://www.github.com/nodejs/node-gyp/commit/e199cfa8fc6161492d2a6ade2190510d0ebf7c0f))
+* **wiki:** Add helpful information ([4eda827](https://www.github.com/nodejs/node-gyp/commit/4eda8275c03dae6d2f5c40f3c1dbe930d84b0f2b))
+* **wiki:** Add node-canvas ([13a9553](https://www.github.com/nodejs/node-gyp/commit/13a955317b39caf98fd1f412d8d3f41599e979fd))
+* **wiki:** Add node-openvg-canvas and node-openvg. ([61f709e](https://www.github.com/nodejs/node-gyp/commit/61f709ec4d9f256a6467e9ff84430a48eeb629d1))
+* **wiki:** add one more example ([77f3632](https://www.github.com/nodejs/node-gyp/commit/77f363272930d3d4d24fd3973be22e6237128fcc))
+* **wiki:** add topcube, node-osmium, and node-osrm ([1a75d2b](https://www.github.com/nodejs/node-gyp/commit/1a75d2bf2f562ba50846893a516e111cfbb50885))
+* **wiki:** Added details for properly fixing ([3d4d9d5](https://www.github.com/nodejs/node-gyp/commit/3d4d9d52d6b5b49de06bb0bb5b68e2686d2b7ebd))
+* **wiki:** Added Ghostscript4JS ([bf4bed1](https://www.github.com/nodejs/node-gyp/commit/bf4bed1b96a7d22fba6f97f4552ad09f32ac3737))
+* **wiki:** added levelup ([1575bce](https://www.github.com/nodejs/node-gyp/commit/1575bce3a53db628bfb023fd6f3258fdf98c3195))
+* **wiki:** Added nk-mysql (nodamysql) ([5b4f2d0](https://www.github.com/nodejs/node-gyp/commit/5b4f2d0e1d5d3eadfd03aaf9c1668340f76c4bea))
+* **wiki:** Added nk-xrm-installer .gyp references, including .py scripts for providing complete reference to examples of fetching source via http, extracting, and moving files (as opposed to copying) ([ceb3088](https://www.github.com/nodejs/node-gyp/commit/ceb30885b74f6789374ef52267b84767be93ebe4))
+* **wiki:** Added tip about resolving frustrating LNK1181 error ([e64798d](https://www.github.com/nodejs/node-gyp/commit/e64798de8cac6031ad598a86d7599e81b4d20b17))
+* **wiki:** ADDED: Node.js binding to OpenCV ([e2dc777](https://www.github.com/nodejs/node-gyp/commit/e2dc77730b09d7ee8682d7713a7603a2d7aacabd))
+* **wiki:** Adding link to node-cryptopp's gyp file ([875adbe](https://www.github.com/nodejs/node-gyp/commit/875adbe2a4669fa5f2be0250ffbf98fb55e800fd))
+* **wiki:** Adding the sharp library to the list ([9dce0e4](https://www.github.com/nodejs/node-gyp/commit/9dce0e41650c3fa973e6135a79632d022c662a1d))
+* **wiki:** Adds node-fann ([23e3d48](https://www.github.com/nodejs/node-gyp/commit/23e3d485ed894ba7c631e9c062f5e366b50c416c))
+* **wiki:** Adds node-inotify and v8-profiler ([b6e542f](https://www.github.com/nodejs/node-gyp/commit/b6e542f644dbbfe22b88524ec500696e06ee4af7))
+* **wiki:** Bumping Python version from 2.3 to 2.7 as per the node-gyp readme ([55ebd6e](https://www.github.com/nodejs/node-gyp/commit/55ebd6ebacde975bf84f7bf4d8c66e64cc7cd0da))
+* **wiki:** C++ build tools version upgraded ([5b899b7](https://www.github.com/nodejs/node-gyp/commit/5b899b70db729c392ced7c98e8e17590c6499fc3))
+* **wiki:** change bcrypt url to binding.gyp file ([e11bdd8](https://www.github.com/nodejs/node-gyp/commit/e11bdd84de6144492d3eb327d67cbf2d62da1a76))
+* **wiki:** Clarification + direct link to VS2010 ([531c724](https://www.github.com/nodejs/node-gyp/commit/531c724561d947b5d870de8d52dd8c3c51c5ec2d))
+* **wiki:** Correcting the link to node-osmium ([fae7516](https://www.github.com/nodejs/node-gyp/commit/fae7516a1d2829b6e234eaded74fb112ebd79a05))
+* **wiki:** Created "binding.gyp" files out in the wild (markdown) ([d4fd143](https://www.github.com/nodejs/node-gyp/commit/d4fd14355bbe57f229f082f47bb2b3670868203f))
+* **wiki:** Created Common issues (markdown) ([a38299e](https://www.github.com/nodejs/node-gyp/commit/a38299ea340ceb0e732c6dc6a1b4760257644839))
+* **wiki:** Created Error: "pre" versions of node cannot be installed (markdown) ([98bc80d](https://www.github.com/nodejs/node-gyp/commit/98bc80d7a62ba70c881f3c39d94f804322e57852))
+* **wiki:** Created Linking to OpenSSL (markdown) ([c46d00d](https://www.github.com/nodejs/node-gyp/commit/c46d00d83bac5173dea8bbbb175a1a7de74fdaca))
+* **wiki:** Created Updating npm's bundled node gyp (markdown) ([e0ac8d1](https://www.github.com/nodejs/node-gyp/commit/e0ac8d15af46aadd1c220599e63199b154a514e6))
+* **wiki:** Created use of undeclared identifier 'TypedArray' (markdown) ([65ba711](https://www.github.com/nodejs/node-gyp/commit/65ba71139e9b7f64ac823e575ee9dbf17d937ce4))
+* **wiki:** Created Visual Studio 2010 Setup (markdown) ([5b80e83](https://www.github.com/nodejs/node-gyp/commit/5b80e834c8f79dda9fb2770a876ff3cf649c06f3))
+* **wiki:** Created Visual studio 2012 setup (markdown) ([becef31](https://www.github.com/nodejs/node-gyp/commit/becef316b6c46a33e783667720ee074a0141d1a5))
+* **wiki:** Destroyed Visual Studio 2010 Setup (markdown) ([93423b4](https://www.github.com/nodejs/node-gyp/commit/93423b43606de9664aeb79635825f5e9941ec9bc))
+* **wiki:** Destroyed Visual studio 2012 setup (markdown) ([3601508](https://www.github.com/nodejs/node-gyp/commit/3601508bb10fa05da0ddc7e70d57e4b4dd679657))
+* **wiki:** Different commands for Windows npm v6 vs. v7 ([0fce46b](https://www.github.com/nodejs/node-gyp/commit/0fce46b53340c85e8091cde347d5ed23a443c82f))
+* **wiki:** Drop  in favor of ([9285ff6](https://www.github.com/nodejs/node-gyp/commit/9285ff6e451c52c070a05f05f0a9602621d91d53))
+* **wiki:** Explicit link to Visual C++ 2010 Express ([378c363](https://www.github.com/nodejs/node-gyp/commit/378c3632f02c096ed819ec8f2611c65bef0c0554))
+* **wiki:** fix link to gyp file used to build libsqlite3 ([54db8d7](https://www.github.com/nodejs/node-gyp/commit/54db8d7ac33e3f98220960b5d86cfa18a75b53cb))
+* **wiki:** Fix link to node-zipfile ([92e49a8](https://www.github.com/nodejs/node-gyp/commit/92e49a858ed69cb4847a26a5676ab56ef5e2de33))
+* **wiki:** fixed node-serialport link ([954ee53](https://www.github.com/nodejs/node-gyp/commit/954ee530b3972d1db591fce32368e4e31b5a25d8))
+* **wiki:** I highly missing it in common issue as every windows biggner face that issue ([d617fae](https://www.github.com/nodejs/node-gyp/commit/d617faee29c40871ca5c8f93efd0ce929a40d541))
+* **wiki:** if ouns that the -h did not help. I founs on github that there was support for visual studio 2015, while i couldn't install node-red beacuse it kept telling me the key 2015 was missing. looking in he gyp python code i found the local file was bot up t dat with the github repo. updating took several efforts before i tried to drop the -g option. ([408b72f](https://www.github.com/nodejs/node-gyp/commit/408b72f561329408daeb17834436e381406efcc8))
+* **wiki:** If permissions error, please try  and then the command. ([ee8e1c1](https://www.github.com/nodejs/node-gyp/commit/ee8e1c1e5334096d58e0d6bca6c006f2ee9c88cb))
+* **wiki:** Improve Unix instructions ([c3e5487](https://www.github.com/nodejs/node-gyp/commit/c3e548736645b535ea5bce613d74ca3e98598243))
+* **wiki:** link to docs/ from README ([b52e487](https://www.github.com/nodejs/node-gyp/commit/b52e487eac1eb421573d1e67114a242eeff45a00))
+* **wiki:** Lower case L ([3aa2c6b](https://www.github.com/nodejs/node-gyp/commit/3aa2c6bdb07971b87505e32e32548d75264bd19f))
+* **wiki:** Make changes discussed in https://github.com/nodejs/node-gyp/issues/2416 ([1dcad87](https://www.github.com/nodejs/node-gyp/commit/1dcad873539027511a5f0243baf770ea90f6f4e2))
+* **wiki:** move wiki docs into doc/ ([f0a4835](https://www.github.com/nodejs/node-gyp/commit/f0a48355d86534ec3bdabcdb3ce3340fa2e17f39))
+* **wiki:** node-sass in the wild ([d310a73](https://www.github.com/nodejs/node-gyp/commit/d310a73d64d0065050377baac7047472f7424a1b))
+* **wiki:** node-srs was a 404 ([bbca21a](https://www.github.com/nodejs/node-gyp/commit/bbca21a1e1ede4c473aff365ca71989a5bda7b57))
+* **wiki:** Note: VS2010 seems to be no longer available!  VS2013 or nothing! ([7b5dcaf](https://www.github.com/nodejs/node-gyp/commit/7b5dcafafccdceae4b8f2b53ac9081a694b6ade8))
+* **wiki:** safer doc names, remove unnecessary TypedArray doc ([161c235](https://www.github.com/nodejs/node-gyp/commit/161c2353ef5b562f4acfb2fd77608fcbd0800fc0))
+* **wiki:** sorry, forgot to mention a specific windows version. ([d69dffc](https://www.github.com/nodejs/node-gyp/commit/d69dffc16c2b1e3c60dcb5d1c35a49270ba22a35))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([7444b47](https://www.github.com/nodejs/node-gyp/commit/7444b47a7caac1e14d1da474a7fcfcf88d328017))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([d766b74](https://www.github.com/nodejs/node-gyp/commit/d766b7427851e6c2edc02e2504a7be9be7e330c0))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([d319b0e](https://www.github.com/nodejs/node-gyp/commit/d319b0e98c7085de8e51bc5595eba4264b99a7d5))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([3c6692d](https://www.github.com/nodejs/node-gyp/commit/3c6692d538f0ce973869aa237118b7d2483feccd))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([93392d5](https://www.github.com/nodejs/node-gyp/commit/93392d559ce6f250b9c7fe8177e6c88603809dc1))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([8841158](https://www.github.com/nodejs/node-gyp/commit/88411588f300e9b7c00fe516ecd977a1feeeb15c))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([81bfa1f](https://www.github.com/nodejs/node-gyp/commit/81bfa1f1b63d522a9f8a9ae9ca0c7ae90fe75140))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([d1cd237](https://www.github.com/nodejs/node-gyp/commit/d1cd237bad06fa507adb354b9e2181a14dc63d24))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([3de9e17](https://www.github.com/nodejs/node-gyp/commit/3de9e17e0b8a387eafe7bd18d0ec1e3191d118e8))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([a9b7096](https://www.github.com/nodejs/node-gyp/commit/a9b70968fb956eab3b95672048b94350e1565ca3))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([3236069](https://www.github.com/nodejs/node-gyp/commit/3236069689e7e0eb15b324fce74ab58158956f98))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([1462755](https://www.github.com/nodejs/node-gyp/commit/14627556966e5d513bdb8e5208f0e1300f68991f))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([7ab1337](https://www.github.com/nodejs/node-gyp/commit/7ab133752a6c402bb96dcd3d671d73e03e9487ad))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([640895d](https://www.github.com/nodejs/node-gyp/commit/640895d36b7448c646a3b850c1e159106f83c724))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([ced8c96](https://www.github.com/nodejs/node-gyp/commit/ced8c968457f285ab8989c291d28173d7730833c))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([27b883a](https://www.github.com/nodejs/node-gyp/commit/27b883a350ad0db6b9130d7b996f35855ec34c7a))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([d29fb13](https://www.github.com/nodejs/node-gyp/commit/d29fb134f1c4b9dd729ba95f2979e69e0934809f))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([2765891](https://www.github.com/nodejs/node-gyp/commit/27658913e6220cf0371b4b73e25a0e4ab11108a1))
+* **wiki:** Updated "binding.gyp" files out in the wild (markdown) ([dc97766](https://www.github.com/nodejs/node-gyp/commit/dc9776648d432bca6775c176641f16da14522d4c))
+* **wiki:** Updated Error: "pre" versions of node cannot be installed (markdown) ([e9f8b33](https://www.github.com/nodejs/node-gyp/commit/e9f8b33d1f87d04f22cb09a814d7c55d0fa38446))
+* **wiki:** Updated Home (markdown) ([3407109](https://www.github.com/nodejs/node-gyp/commit/3407109325cf7ba1e925656b9eb75feffab0557c))
+* **wiki:** Updated Home (markdown) ([6e392bc](https://www.github.com/nodejs/node-gyp/commit/6e392bcdd3dd1691773e6e16e1dffc35931b81e0))
+* **wiki:** Updated Home (markdown) ([65efe32](https://www.github.com/nodejs/node-gyp/commit/65efe32ccb8d446ce569453364f922dd9d27c945))
+* **wiki:** Updated Home (markdown) ([ea28f09](https://www.github.com/nodejs/node-gyp/commit/ea28f0947af91fa638be355143f5df89d2e431c8))
+* **wiki:** Updated Home (markdown) ([0e37ff4](https://www.github.com/nodejs/node-gyp/commit/0e37ff48b306c12149661b375895741d3d710da7))
+* **wiki:** Updated Home (markdown) ([b398ef4](https://www.github.com/nodejs/node-gyp/commit/b398ef46f660d2b1506508550dadfb4c35639e4b))
+* **wiki:** Updated Linking to OpenSSL (markdown) ([8919028](https://www.github.com/nodejs/node-gyp/commit/8919028921fd304f08044098434f0dc6071fb7cf))
+* **wiki:** Updated Linking to OpenSSL (markdown) ([c00eb77](https://www.github.com/nodejs/node-gyp/commit/c00eb778fc7dc27e4dab3a9219035ea20458b33b))
+* **wiki:** Updated node-levelup to node-leveldown (broken links) ([59668bb](https://www.github.com/nodejs/node-gyp/commit/59668bb0b904feccf3c09afa2fd37378c77af967))
+* **wiki:** Updated Updating npm's bundled node gyp (markdown) ([d314854](https://www.github.com/nodejs/node-gyp/commit/d31485415ef69d46effa6090c95698341965de1b))
+* **wiki:** Updated Updating npm's bundled node gyp (markdown) ([11858b0](https://www.github.com/nodejs/node-gyp/commit/11858b0655d1eee00c62ad628e719d4378803d14))
+* **wiki:** Updated Updating npm's bundled node gyp (markdown) ([33561e9](https://www.github.com/nodejs/node-gyp/commit/33561e9cbf5f4eb46111318503c77df2c6eb484a))
+* **wiki:** Updated Updating npm's bundled node gyp (markdown) ([4a7f2d0](https://www.github.com/nodejs/node-gyp/commit/4a7f2d0d869a65c99a78504976567017edadf657))
+* **wiki:** Updated Updating npm's bundled node gyp (markdown) ([979a706](https://www.github.com/nodejs/node-gyp/commit/979a7063b950c088a7f4896fc3a48e1d00dfd231))
+* **wiki:** Updated Updating npm's bundled node gyp (markdown) ([e50e04d](https://www.github.com/nodejs/node-gyp/commit/e50e04d7b6a3754ea0aa11fe8cef491b3bc5bdd4))
+
+## [8.1.0](https://www.github.com/nodejs/node-gyp/compare/v8.0.0...v8.1.0) (2021-05-28)
+
+
+### Features
+
+* **gyp:** update gyp to v0.9.1 ([#2402](https://www.github.com/nodejs/node-gyp/issues/2402)) ([814b1b0](https://www.github.com/nodejs/node-gyp/commit/814b1b0eda102afb9fc87e81638a9cf5b650bb10))
+
+
+### Miscellaneous
+
+* add `release-please-action` for automated releases ([#2395](https://www.github.com/nodejs/node-gyp/issues/2395)) ([07e9d7c](https://www.github.com/nodejs/node-gyp/commit/07e9d7c7ee80ba119ea760c635f72fd8e7efe198))
+
+
+### Core
+
+* fail gracefully if we can't find the username ([#2375](https://www.github.com/nodejs/node-gyp/issues/2375)) ([fca4795](https://www.github.com/nodejs/node-gyp/commit/fca4795512c67dc8420aaa0d913b5b89a4b147f3))
+* log as yes/no whether build dir was created ([#2370](https://www.github.com/nodejs/node-gyp/issues/2370)) ([245dee5](https://www.github.com/nodejs/node-gyp/commit/245dee5b62581309946872ae253226ea3a42c0e3))
+
+
+### Doc
+
+* fix v8.0.0 release date ([4b83c3d](https://www.github.com/nodejs/node-gyp/commit/4b83c3de7300457919d53f26d96ea9ad6f6bedd8))
+* remove redundant version info ([#2403](https://www.github.com/nodejs/node-gyp/issues/2403)) ([1423670](https://www.github.com/nodejs/node-gyp/commit/14236709de64b100a424396b91a5115639daa0ef))
+* Update README.md Visual Studio Community page polski to auto ([#2371](https://www.github.com/nodejs/node-gyp/issues/2371)) ([1b4697a](https://www.github.com/nodejs/node-gyp/commit/1b4697abf69ef574a48faf832a7098f4c6c224a5))
+
+## v8.0.0 2021-04-03
+
+* [[`0d8a6f1b19`](https://github.com/nodejs/node-gyp/commit/0d8a6f1b19)] - **ci**: update actions/setup-node to v2 (#2302) (Sora Morimoto) [#2302](https://github.com/nodejs/node-gyp/pull/2302)
+* [[`15a5c7d45b`](https://github.com/nodejs/node-gyp/commit/15a5c7d45b)] - **ci**: migrate deprecated grammar (#2285) (Jiawen Geng) [#2285](https://github.com/nodejs/node-gyp/pull/2285)
+* [[`06ddde27f9`](https://github.com/nodejs/node-gyp/commit/06ddde27f9)] - **deps**: sync mutual dependencies with npm (DeeDeeG) [#2348](https://github.com/nodejs/node-gyp/pull/2348)
+* [[`a5fd1f41e3`](https://github.com/nodejs/node-gyp/commit/a5fd1f41e3)] - **doc**: add downloads badge (#2352) (Jiawen Geng) [#2352](https://github.com/nodejs/node-gyp/pull/2352)
+* [[`cc1cbce056`](https://github.com/nodejs/node-gyp/commit/cc1cbce056)] - **doc**: update macOS\_Catalina.md (#2293) (iMrLopez) [#2293](https://github.com/nodejs/node-gyp/pull/2293)
+* [[`6287118fc4`](https://github.com/nodejs/node-gyp/commit/6287118fc4)] - **doc**: updated README.md to copy easily (#2281) (மனோஜ்குமார் பழனிச்சாமி) [#2281](https://github.com/nodejs/node-gyp/pull/2281)
+* [[`66c0f04467`](https://github.com/nodejs/node-gyp/commit/66c0f04467)] - **doc**: add missing `sudo` to Catalina doc (Karl Horky) [#2244](https://github.com/nodejs/node-gyp/pull/2244)
+* [[`0da2e0140d`](https://github.com/nodejs/node-gyp/commit/0da2e0140d)] - **gyp**: update gyp to v0.8.1 (#2355) (DeeDeeG) [#2355](https://github.com/nodejs/node-gyp/pull/2355)
+* [[`0093ec8646`](https://github.com/nodejs/node-gyp/commit/0093ec8646)] - **gyp**: Improve our flake8 linting tests (Christian Clauss) [#2356](https://github.com/nodejs/node-gyp/pull/2356)
+* [[`a78b584236`](https://github.com/nodejs/node-gyp/commit/a78b584236)] - **(SEMVER-MAJOR)** **gyp**: remove support for Python 2 (#2300) (Christian Clauss) [#2300](https://github.com/nodejs/node-gyp/pull/2300)
+* [[`c3c510d89e`](https://github.com/nodejs/node-gyp/commit/c3c510d89e)] - **gyp**: update gyp to v0.8.0 (#2318) (Christian Clauss) [#2318](https://github.com/nodejs/node-gyp/pull/2318)
+* [[`9e1397c52e`](https://github.com/nodejs/node-gyp/commit/9e1397c52e)] - **(SEMVER-MAJOR)** **gyp**: update gyp to v0.7.0 (#2284) (Jiawen Geng) [#2284](https://github.com/nodejs/node-gyp/pull/2284)
+* [[`1bd18f3e77`](https://github.com/nodejs/node-gyp/commit/1bd18f3e77)] - **(SEMVER-MAJOR)** **lib**: drop Python 2 support in find-python.js (#2333) (DeeDeeG) [#2333](https://github.com/nodejs/node-gyp/pull/2333)
+* [[`e81602ef55`](https://github.com/nodejs/node-gyp/commit/e81602ef55)] - **(SEMVER-MAJOR)** **lib**: migrate requests to fetch (#2220) (Matias Lopez) [#2220](https://github.com/nodejs/node-gyp/pull/2220)
+* [[`392b7760b4`](https://github.com/nodejs/node-gyp/commit/392b7760b4)] - **lib**: avoid changing process.config (#2322) (Michaël Zasso) [#2322](https://github.com/nodejs/node-gyp/pull/2322)
+
+## v7.1.2 2020-10-17
+
+* [[`096e3aded5`](https://github.com/nodejs/node-gyp/commit/096e3aded5)] - **gyp**: update gyp to 0.6.2 (Myles Borins) [#2241](https://github.com/nodejs/node-gyp/pull/2241)
+* [[`54f97cd243`](https://github.com/nodejs/node-gyp/commit/54f97cd243)] - **doc**: add cmd to reset `xcode-select` to initial state (Valera Rozuvan) [#2235](https://github.com/nodejs/node-gyp/pull/2235)
+
+## v7.1.1 2020-10-15
+
+This release restores the location of shared library builds to the pre-v7
+location. In v7.0.0 until this release, shared library outputs were placed
+in a lib.target subdirectory inside the build/{Release,Debug} directory for
+builds using `make` (Linux, etc.). This is inconsistent with macOS (Xcode)
+behavior and previous node-gyp behavior so has been reverted.
+We consider this a bug-fix rather than semver-major change.
+
+* [[`18bf2d1d38`](https://github.com/nodejs/node-gyp/commit/18bf2d1d38)] - **deps**: update deps to match npm@7 (Rod Vagg) [#2240](https://github.com/nodejs/node-gyp/pull/2240)
+* [[`ee6a837cb7`](https://github.com/nodejs/node-gyp/commit/ee6a837cb7)] - **gyp**: update gyp to 0.6.1 (Rod Vagg) [#2238](https://github.com/nodejs/node-gyp/pull/2238)
+* [[`3e7f8ccafc`](https://github.com/nodejs/node-gyp/commit/3e7f8ccafc)] - **lib**: better log message when ps fails (Martin Midtgaard) [#2229](https://github.com/nodejs/node-gyp/pull/2229)
+* [[`7fb314339f`](https://github.com/nodejs/node-gyp/commit/7fb314339f)] - **test**: GitHub Actions: Test on Python 3.9 (Christian Clauss) [#2230](https://github.com/nodejs/node-gyp/pull/2230)
+* [[`754996b9ec`](https://github.com/nodejs/node-gyp/commit/754996b9ec)] - **doc**: replace status badges with new Actions badge (Rod Vagg) [#2218](https://github.com/nodejs/node-gyp/pull/2218)
+* [[`2317dc400c`](https://github.com/nodejs/node-gyp/commit/2317dc400c)] - **ci**: switch to GitHub Actions (Shelley Vohr) [#2210](https://github.com/nodejs/node-gyp/pull/2210)
+* [[`2cca9b74f7`](https://github.com/nodejs/node-gyp/commit/2cca9b74f7)] - **doc**: drop the --production flag for installing windows-build-tools (DeeDeeG) [#2206](https://github.com/nodejs/node-gyp/pull/2206)
+
+## v7.1.0 2020-08-12
+
+* [[`aaf33c3029`](https://github.com/nodejs/node-gyp/commit/aaf33c3029)] - **build**: add update-gyp script (Samuel Attard) [#2167](https://github.com/nodejs/node-gyp/pull/2167)
+* * [[`3baa4e4172`](https://github.com/nodejs/node-gyp/commit/3baa4e4172)] - **(SEMVER-MINOR)** **gyp**: update gyp to 0.4.0 (Samuel Attard) [#2165](https://github.com/nodejs/node-gyp/pull/2165)
+* * [[`f461d56c53`](https://github.com/nodejs/node-gyp/commit/f461d56c53)] - **(SEMVER-MINOR)** **build**: support apple silicon (arm64 darwin) builds (Samuel Attard) [#2165](https://github.com/nodejs/node-gyp/pull/2165)
+* * [[`ee6fa7d3bc`](https://github.com/nodejs/node-gyp/commit/ee6fa7d3bc)] - **docs**: note that node-gyp@7 should solve Catalina CLT issues (Rod Vagg) [#2156](https://github.com/nodejs/node-gyp/pull/2156)
+* * [[`4fc8ff179d`](https://github.com/nodejs/node-gyp/commit/4fc8ff179d)] - **doc**: silence curl for macOS Catalina acid test (Chia Wei Ong) [#2150](https://github.com/nodejs/node-gyp/pull/2150)
+* * [[`7857cb2eb1`](https://github.com/nodejs/node-gyp/commit/7857cb2eb1)] - **deps**: increase "engines" to "node" : "\>= 10.12.0" (DeeDeeG) [#2153](https://github.com/nodejs/node-gyp/pull/2153)
+
+## v7.0.0 2020-06-03
+
+* [[`e18a61afc1`](https://github.com/nodejs/node-gyp/commit/e18a61afc1)] - **build**: shrink bloated addon binaries on windows (Shelley Vohr) [#2060](https://github.com/nodejs/node-gyp/pull/2060)
+* [[`4937722cf5`](https://github.com/nodejs/node-gyp/commit/4937722cf5)] - **(SEMVER-MAJOR)** **deps**: replace mkdirp with {recursive} mkdir (Rod Vagg) [#2123](https://github.com/nodejs/node-gyp/pull/2123)
+* [[`d45438a047`](https://github.com/nodejs/node-gyp/commit/d45438a047)] - **(SEMVER-MAJOR)** **deps**: update deps, match to npm@7 (Rod Vagg) [#2126](https://github.com/nodejs/node-gyp/pull/2126)
+* [[`ba4f34b7d6`](https://github.com/nodejs/node-gyp/commit/ba4f34b7d6)] - **doc**: update catalina xcode clt download link (Dario Vladovic) [#2133](https://github.com/nodejs/node-gyp/pull/2133)
+* [[`f7bfce96ed`](https://github.com/nodejs/node-gyp/commit/f7bfce96ed)] - **doc**: update acid test and introduce curl|bash test script (Dario Vladovic) [#2105](https://github.com/nodejs/node-gyp/pull/2105)
+* [[`e529f3309d`](https://github.com/nodejs/node-gyp/commit/e529f3309d)] - **doc**: update README to reflect upgrade to gyp-next (Ujjwal Sharma) [#2092](https://github.com/nodejs/node-gyp/pull/2092)
+* [[`9aed6286a3`](https://github.com/nodejs/node-gyp/commit/9aed6286a3)] - **doc**: give more attention to Catalina issues doc (Matheus Marchini) [#2134](https://github.com/nodejs/node-gyp/pull/2134)
+* [[`963f2a7b48`](https://github.com/nodejs/node-gyp/commit/963f2a7b48)] - **doc**: improve Catalina discoverability for search engines (Matheus Marchini) [#2135](https://github.com/nodejs/node-gyp/pull/2135)
+* [[`7b75af349b`](https://github.com/nodejs/node-gyp/commit/7b75af349b)] - **doc**: add macOS Catalina software update info (Karl Horky) [#2078](https://github.com/nodejs/node-gyp/pull/2078)
+* [[`4f23c7bee2`](https://github.com/nodejs/node-gyp/commit/4f23c7bee2)] - **doc**: update link to the code of conduct (#2073) (Michaël Zasso) [#2073](https://github.com/nodejs/node-gyp/pull/2073)
+* [[`473cfa283f`](https://github.com/nodejs/node-gyp/commit/473cfa283f)] - **doc**: note in README that Python 3.8 is supported (#2072) (Michaël Zasso) [#2072](https://github.com/nodejs/node-gyp/pull/2072)
+* [[`e7402b4a7c`](https://github.com/nodejs/node-gyp/commit/e7402b4a7c)] - **doc**: update catalina xcode cli tools download link (#2044) (Dario Vladović) [#2044](https://github.com/nodejs/node-gyp/pull/2044)
+* [[`35de45984f`](https://github.com/nodejs/node-gyp/commit/35de45984f)] - **doc**: update catalina xcode cli tools download link; formatting (Jonathan Hult) [#2034](https://github.com/nodejs/node-gyp/pull/2034)
+* [[`48642191f5`](https://github.com/nodejs/node-gyp/commit/48642191f5)] - **doc**: add download link for Command Line Tools for Xcode (Przemysław Bitkowski) [#2029](https://github.com/nodejs/node-gyp/pull/2029)
+* [[`ae5b150051`](https://github.com/nodejs/node-gyp/commit/ae5b150051)] - **doc**: Catalina suggestion: remove /Library/Developer/CommandLineTools (Christian Clauss) [#2022](https://github.com/nodejs/node-gyp/pull/2022)
+* [[`d1dea13fe4`](https://github.com/nodejs/node-gyp/commit/d1dea13fe4)] - **doc**: fix changelog 6.1.0 release year to be 2020 (Quentin Vernot) [#2021](https://github.com/nodejs/node-gyp/pull/2021)
+* [[`6356117b08`](https://github.com/nodejs/node-gyp/commit/6356117b08)] - **doc, bin**: stop suggesting opening  node-gyp issues (Bartosz Sosnowski) [#2096](https://github.com/nodejs/node-gyp/pull/2096)
+* [[`a6b76a8b48`](https://github.com/nodejs/node-gyp/commit/a6b76a8b48)] - **gyp**: update gyp to 0.2.1 (Ujjwal Sharma) [#2092](https://github.com/nodejs/node-gyp/pull/2092)
+* [[`ebc34ec823`](https://github.com/nodejs/node-gyp/commit/ebc34ec823)] - **gyp**: update gyp to 0.2.0 (Ujjwal Sharma) [#2092](https://github.com/nodejs/node-gyp/pull/2092)
+* [[`972780bde7`](https://github.com/nodejs/node-gyp/commit/972780bde7)] - **(SEMVER-MAJOR)** **gyp**: sync code base with nodejs repo (#1975) (Michaël Zasso) [#1975](https://github.com/nodejs/node-gyp/pull/1975)
+* [[`c255ffbf6a`](https://github.com/nodejs/node-gyp/commit/c255ffbf6a)] - **lib**: drop "-2" flag for "py.exe" launcher (DeeDeeG) [#2131](https://github.com/nodejs/node-gyp/pull/2131)
+* [[`1f7e1e93b5`](https://github.com/nodejs/node-gyp/commit/1f7e1e93b5)] - **lib**: ignore VS instances that cause COMExceptions (Andrew Casey) [#2018](https://github.com/nodejs/node-gyp/pull/2018)
+* [[`741ab096d5`](https://github.com/nodejs/node-gyp/commit/741ab096d5)] - **test**: remove support for EOL versions of Node.js (Shelley Vohr)
+* [[`ca86ef2539`](https://github.com/nodejs/node-gyp/commit/ca86ef2539)] - **test**: bump actions/checkout from v1 to v2 (BSKY) [#2063](https://github.com/nodejs/node-gyp/pull/2063)
+
+## v6.1.0 2020-01-08
+
+* [[`9a7dd16b76`](https://github.com/nodejs/node-gyp/commit/9a7dd16b76)] - **doc**: remove backticks from Python version list (Rod Vagg) [#2011](https://github.com/nodejs/node-gyp/pull/2011)
+* [[`26cd6eaea6`](https://github.com/nodejs/node-gyp/commit/26cd6eaea6)] - **doc**: add GitHub Actions badge (#1994) (Rod Vagg) [#1994](https://github.com/nodejs/node-gyp/pull/1994)
+* [[`312c12ef4f`](https://github.com/nodejs/node-gyp/commit/312c12ef4f)] - **doc**: update macOS\_Catalina.md (#1992) (James Home) [#1992](https://github.com/nodejs/node-gyp/pull/1992)
+* [[`f7b6b6b77b`](https://github.com/nodejs/node-gyp/commit/f7b6b6b77b)] - **doc**: fix typo in README.md (#1985) (Suraneti Rodsuwan) [#1985](https://github.com/nodejs/node-gyp/pull/1985)
+* [[`6b8f2652dd`](https://github.com/nodejs/node-gyp/commit/6b8f2652dd)] - **doc**: add travis badge (Rod Vagg) [#1971](https://github.com/nodejs/node-gyp/pull/1971)
+* [[`20aa0b44f7`](https://github.com/nodejs/node-gyp/commit/20aa0b44f7)] - **doc**: macOS Catalina add two commands (Christian Clauss) [#1962](https://github.com/nodejs/node-gyp/pull/1962)
+* [[`14f2a07a39`](https://github.com/nodejs/node-gyp/commit/14f2a07a39)] - **gyp**: list(dict) so we can del dict(key) while iterating (Christian Clauss) [#2009](https://github.com/nodejs/node-gyp/pull/2009)
+* [[`f242ce4d2c`](https://github.com/nodejs/node-gyp/commit/f242ce4d2c)] - **lib**: compatibility with semver ≥ 7 (`new` for semver.Range) (Xavier Guimard) [#2006](https://github.com/nodejs/node-gyp/pull/2006)
+* [[`3bcba2a01a`](https://github.com/nodejs/node-gyp/commit/3bcba2a01a)] - **(SEMVER-MINOR)** **lib**: noproxy support, match proxy detection to `request` (Matias Lopez) [#1978](https://github.com/nodejs/node-gyp/pull/1978)
+* [[`470cc2178e`](https://github.com/nodejs/node-gyp/commit/470cc2178e)] - **test**: remove old docker test harness (#1993) (Rod Vagg) [#1993](https://github.com/nodejs/node-gyp/pull/1993)
+* [[`31ecc8421d`](https://github.com/nodejs/node-gyp/commit/31ecc8421d)] - **test**: add Windows to GitHub Actions testing (#1996) (Christian Clauss) [#1996](https://github.com/nodejs/node-gyp/pull/1996)
+* [[`5a729e86ee`](https://github.com/nodejs/node-gyp/commit/5a729e86ee)] - **test**: fix typo in header download test (#2001) (Richard Lau) [#2001](https://github.com/nodejs/node-gyp/pull/2001)
+* [[`345c70e56d`](https://github.com/nodejs/node-gyp/commit/345c70e56d)] - **test**: direct python invocation & simpler pyenv (Matias Lopez) [#1979](https://github.com/nodejs/node-gyp/pull/1979)
+* [[`d6a7e0e1fb`](https://github.com/nodejs/node-gyp/commit/d6a7e0e1fb)] - **test**: fix macOS Travis on Python 2.7 & 3.7 (Christian Clauss) [#1979](https://github.com/nodejs/node-gyp/pull/1979)
+* [[`5a64e9bd32`](https://github.com/nodejs/node-gyp/commit/5a64e9bd32)] - **test**: initial Github Actions with Ubuntu & macOS (Christian Clauss) [#1985](https://github.com/nodejs/node-gyp/pull/1985)
+* [[`04da736d38`](https://github.com/nodejs/node-gyp/commit/04da736d38)] - **test**: fix Python unittests (cclauss) [#1961](https://github.com/nodejs/node-gyp/pull/1961)
+* [[`0670e5189d`](https://github.com/nodejs/node-gyp/commit/0670e5189d)] - **test**: add header download test (Rod Vagg) [#1796](https://github.com/nodejs/node-gyp/pull/1796)
+* [[`c506a6a150`](https://github.com/nodejs/node-gyp/commit/c506a6a150)] - **test**: configure proper devDir for invoking configure() (Rod Vagg) [#1796](https://github.com/nodejs/node-gyp/pull/1796)
+
+## v6.0.1 2019-11-01
+
+* [[`8ec2e681d5`](https://github.com/nodejs/node-gyp/commit/8ec2e681d5)] - **doc**: add macOS\_Catalina.md document (cclauss) [#1940](https://github.com/nodejs/node-gyp/pull/1940)
+* [[`1b11be63cc`](https://github.com/nodejs/node-gyp/commit/1b11be63cc)] - **gyp**: python3 fixes: utf8 decode, use of 'None' in eval (Wilfried Goesgens) [#1925](https://github.com/nodejs/node-gyp/pull/1925)
+* [[`c0282daa48`](https://github.com/nodejs/node-gyp/commit/c0282daa48)] - **gyp**: iteritems() -\> items() in compile\_commands\_json.py (cclauss) [#1947](https://github.com/nodejs/node-gyp/pull/1947)
+* [[`d8e09a1b6a`](https://github.com/nodejs/node-gyp/commit/d8e09a1b6a)] - **gyp**: make cmake python3 compatible (gengjiawen) [#1944](https://github.com/nodejs/node-gyp/pull/1944)
+* [[`9c0f3404f0`](https://github.com/nodejs/node-gyp/commit/9c0f3404f0)] - **gyp**: fix TypeError in XcodeVersion() (Christian Clauss) [#1939](https://github.com/nodejs/node-gyp/pull/1939)
+* [[`bb2eb72a3f`](https://github.com/nodejs/node-gyp/commit/bb2eb72a3f)] - **gyp**: finish decode stdout on Python 3 (Christian Clauss) [#1937](https://github.com/nodejs/node-gyp/pull/1937)
+* [[`f0693413d9`](https://github.com/nodejs/node-gyp/commit/f0693413d9)] - **src,win**: allow 403 errors for arm64 node.lib (Richard Lau) [#1934](https://github.com/nodejs/node-gyp/pull/1934)
+* [[`c60c22de58`](https://github.com/nodejs/node-gyp/commit/c60c22de58)] - **deps**: update deps to roughly match current npm@6 (Rod Vagg) [#1920](https://github.com/nodejs/node-gyp/pull/1920)
+* [[`b91718eefc`](https://github.com/nodejs/node-gyp/commit/b91718eefc)] - **test**: upgrade Linux Travis CI to Python 3.8 (Christian Clauss) [#1923](https://github.com/nodejs/node-gyp/pull/1923)
+* [[`3538a317b6`](https://github.com/nodejs/node-gyp/commit/3538a317b6)] - **doc**: adjustments to the README.md for new users (Dan Pike) [#1919](https://github.com/nodejs/node-gyp/pull/1919)
+* [[`4fff8458c0`](https://github.com/nodejs/node-gyp/commit/4fff8458c0)] - **travis**: ignore failed `brew upgrade npm`, update xcode (Christian Clauss) [#1932](https://github.com/nodejs/node-gyp/pull/1932)
+* [[`60e4488f08`](https://github.com/nodejs/node-gyp/commit/60e4488f08)] - **build**: avoid bare exceptions in xcode\_emulation.py (Christian Clauss) [#1932](https://github.com/nodejs/node-gyp/pull/1932)
+* [[`032db2a2d0`](https://github.com/nodejs/node-gyp/commit/032db2a2d0)] - **lib,install**: always download SHA sums on Windows (Sam Hughes) [#1926](https://github.com/nodejs/node-gyp/pull/1926)
+* [[`5a83630c33`](https://github.com/nodejs/node-gyp/commit/5a83630c33)] - **travis**: add Windows + Python 3.8 to the mix (Rod Vagg) [#1921](https://github.com/nodejs/node-gyp/pull/1921)
+
+## v6.0.0 2019-10-04
+
+* [[`dd0e97ef0b`](https://github.com/nodejs/node-gyp/commit/dd0e97ef0b)] - **(SEMVER-MAJOR)** **lib**: try to find `python` after `python3` (Sam Roberts) [#1907](https://github.com/nodejs/node-gyp/pull/1907)
+* [[`f60ed47d14`](https://github.com/nodejs/node-gyp/commit/f60ed47d14)] - **travis**: add Python 3.5 and 3.6 tests on Linux (Christian Clauss) [#1903](https://github.com/nodejs/node-gyp/pull/1903)
+* [[`c763ca1838`](https://github.com/nodejs/node-gyp/commit/c763ca1838)] - **(SEMVER-MAJOR)** **doc**: Declare that node-gyp is Python 3 compatible (cclauss) [#1811](https://github.com/nodejs/node-gyp/pull/1811)
+* [[`3d1c60ab81`](https://github.com/nodejs/node-gyp/commit/3d1c60ab81)] - **(SEMVER-MAJOR)** **lib**: accept Python 3 by default (João Reis) [#1844](https://github.com/nodejs/node-gyp/pull/1844)
+* [[`c6e3b65a23`](https://github.com/nodejs/node-gyp/commit/c6e3b65a23)] - **(SEMVER-MAJOR)** **lib**: raise the minimum Python version from 2.6 to 2.7 (cclauss) [#1818](https://github.com/nodejs/node-gyp/pull/1818)
+
+## v5.1.1 2020-05-25
+
+* [[`bdd3a79abe`](https://github.com/nodejs/node-gyp/commit/bdd3a79abe)] - **build**: shrink bloated addon binaries on windows (Shelley Vohr) [#2060](https://github.com/nodejs/node-gyp/pull/2060)
+* [[`1f2ba75bc0`](https://github.com/nodejs/node-gyp/commit/1f2ba75bc0)] - **doc**: add macOS Catalina software update info (Karl Horky) [#2078](https://github.com/nodejs/node-gyp/pull/2078)
+* [[`c106d915f5`](https://github.com/nodejs/node-gyp/commit/c106d915f5)] - **doc**: update catalina xcode cli tools download link (#2044) (Dario Vladović) [#2044](https://github.com/nodejs/node-gyp/pull/2044)
+* [[`9a6fea92e2`](https://github.com/nodejs/node-gyp/commit/9a6fea92e2)] - **doc**: update catalina xcode cli tools download link; formatting (Jonathan Hult) [#2034](https://github.com/nodejs/node-gyp/pull/2034)
+* [[`59b0b1add8`](https://github.com/nodejs/node-gyp/commit/59b0b1add8)] - **doc**: add download link for Command Line Tools for Xcode (Przemysław Bitkowski) [#2029](https://github.com/nodejs/node-gyp/pull/2029)
+* [[`bb8d0e7b10`](https://github.com/nodejs/node-gyp/commit/bb8d0e7b10)] - **doc**: Catalina suggestion: remove /Library/Developer/CommandLineTools (Christian Clauss) [#2022](https://github.com/nodejs/node-gyp/pull/2022)
+* [[`fb2e80d4e3`](https://github.com/nodejs/node-gyp/commit/fb2e80d4e3)] - **doc**: update link to the code of conduct (#2073) (Michaël Zasso) [#2073](https://github.com/nodejs/node-gyp/pull/2073)
+* [[`251d9c885c`](https://github.com/nodejs/node-gyp/commit/251d9c885c)] - **doc**: note in README that Python 3.8 is supported (#2072) (Michaël Zasso) [#2072](https://github.com/nodejs/node-gyp/pull/2072)
+* [[`2b6fc3c8d6`](https://github.com/nodejs/node-gyp/commit/2b6fc3c8d6)] - **doc, bin**: stop suggesting opening  node-gyp issues (Bartosz Sosnowski) [#2096](https://github.com/nodejs/node-gyp/pull/2096)
+* [[`a876ae58ad`](https://github.com/nodejs/node-gyp/commit/a876ae58ad)] - **test**: bump actions/checkout from v1 to v2 (BSKY) [#2063](https://github.com/nodejs/node-gyp/pull/2063)
+
+## v5.1.0 2020-02-05
+
+* [[`f37a8b40d0`](https://github.com/nodejs/node-gyp/commit/f37a8b40d0)] - **doc**: add GitHub Actions badge (#1994) (Rod Vagg) [#1994](https://github.com/nodejs/node-gyp/pull/1994)
+* [[`cb3f6aae5e`](https://github.com/nodejs/node-gyp/commit/cb3f6aae5e)] - **doc**: update macOS\_Catalina.md (#1992) (James Home) [#1992](https://github.com/nodejs/node-gyp/pull/1992)
+* [[`0607596a4c`](https://github.com/nodejs/node-gyp/commit/0607596a4c)] - **doc**: fix typo in README.md (#1985) (Suraneti Rodsuwan) [#1985](https://github.com/nodejs/node-gyp/pull/1985)
+* [[`0d5a415a14`](https://github.com/nodejs/node-gyp/commit/0d5a415a14)] - **doc**: add travis badge (Rod Vagg) [#1971](https://github.com/nodejs/node-gyp/pull/1971)
+* [[`103740cd95`](https://github.com/nodejs/node-gyp/commit/103740cd95)] - **gyp**: list(dict) so we can del dict(key) while iterating (Christian Clauss) [#2009](https://github.com/nodejs/node-gyp/pull/2009)
+* [[`278dcddbdd`](https://github.com/nodejs/node-gyp/commit/278dcddbdd)] - **lib**: ignore VS instances that cause COMExceptions (Andrew Casey) [#2018](https://github.com/nodejs/node-gyp/pull/2018)
+* [[`1694907bbf`](https://github.com/nodejs/node-gyp/commit/1694907bbf)] - **lib**: compatibility with semver ≥ 7 (`new` for semver.Range) (Xavier Guimard) [#2006](https://github.com/nodejs/node-gyp/pull/2006)
+* [[`a3f1143514`](https://github.com/nodejs/node-gyp/commit/a3f1143514)] - **(SEMVER-MINOR)** **lib**: noproxy support, match proxy detection to `request` (Matias Lopez) [#1978](https://github.com/nodejs/node-gyp/pull/1978)
+* [[`52365819c7`](https://github.com/nodejs/node-gyp/commit/52365819c7)] - **test**: remove old docker test harness (#1993) (Rod Vagg) [#1993](https://github.com/nodejs/node-gyp/pull/1993)
+* [[`bc509c511d`](https://github.com/nodejs/node-gyp/commit/bc509c511d)] - **test**: add Windows to GitHub Actions testing (#1996) (Christian Clauss) [#1996](https://github.com/nodejs/node-gyp/pull/1996)
+* [[`91ee26dd48`](https://github.com/nodejs/node-gyp/commit/91ee26dd48)] - **test**: fix typo in header download test (#2001) (Richard Lau) [#2001](https://github.com/nodejs/node-gyp/pull/2001)
+* [[`0923f344c9`](https://github.com/nodejs/node-gyp/commit/0923f344c9)] - **test**: direct python invocation & simpler pyenv (Matias Lopez) [#1979](https://github.com/nodejs/node-gyp/pull/1979)
+* [[`32c8744b34`](https://github.com/nodejs/node-gyp/commit/32c8744b34)] - **test**: fix macOS Travis on Python 2.7 & 3.7 (Christian Clauss) [#1979](https://github.com/nodejs/node-gyp/pull/1979)
+* [[`fd4b1351e4`](https://github.com/nodejs/node-gyp/commit/fd4b1351e4)] - **test**: initial Github Actions with Ubuntu & macOS (Christian Clauss) [#1985](https://github.com/nodejs/node-gyp/pull/1985)
+
+## v5.0.7 2019-12-16
+
+Republish of v5.0.6 with unnecessary tarball removed from pack file.
+
+## v5.0.6 2019-12-16
+
+* [[`cdec00286f`](https://github.com/nodejs/node-gyp/commit/cdec00286f)] - **doc**: adjustments to the README.md for new users (Dan Pike) [#1919](https://github.com/nodejs/node-gyp/pull/1919)
+* [[`b7c8233ef2`](https://github.com/nodejs/node-gyp/commit/b7c8233ef2)] - **test**: fix Python unittests (cclauss) [#1961](https://github.com/nodejs/node-gyp/pull/1961)
+* [[`e12b00ab0a`](https://github.com/nodejs/node-gyp/commit/e12b00ab0a)] - **doc**: macOS Catalina add two commands (Christian Clauss) [#1962](https://github.com/nodejs/node-gyp/pull/1962)
+* [[`70b9890c0d`](https://github.com/nodejs/node-gyp/commit/70b9890c0d)] - **test**: add header download test (Rod Vagg) [#1796](https://github.com/nodejs/node-gyp/pull/1796)
+* [[`4029fa8629`](https://github.com/nodejs/node-gyp/commit/4029fa8629)] - **test**: configure proper devDir for invoking configure() (Rod Vagg) [#1796](https://github.com/nodejs/node-gyp/pull/1796)
+* [[`fe8b02cc8b`](https://github.com/nodejs/node-gyp/commit/fe8b02cc8b)] - **doc**: add macOS\_Catalina.md document (cclauss) [#1940](https://github.com/nodejs/node-gyp/pull/1940)
+* [[`8ea47ce365`](https://github.com/nodejs/node-gyp/commit/8ea47ce365)] - **gyp**: python3 fixes: utf8 decode, use of 'None' in eval (Wilfried Goesgens) [#1925](https://github.com/nodejs/node-gyp/pull/1925)
+* [[`c7229716ba`](https://github.com/nodejs/node-gyp/commit/c7229716ba)] - **gyp**: iteritems() -\> items() in compile\_commands\_json.py (cclauss) [#1947](https://github.com/nodejs/node-gyp/pull/1947)
+* [[`2a18b2a0f8`](https://github.com/nodejs/node-gyp/commit/2a18b2a0f8)] - **gyp**: make cmake python3 compatible (gengjiawen) [#1944](https://github.com/nodejs/node-gyp/pull/1944)
+* [[`70f391e844`](https://github.com/nodejs/node-gyp/commit/70f391e844)] - **gyp**: fix TypeError in XcodeVersion() (Christian Clauss) [#1939](https://github.com/nodejs/node-gyp/pull/1939)
+* [[`9f4f0fa34e`](https://github.com/nodejs/node-gyp/commit/9f4f0fa34e)] - **gyp**: finish decode stdout on Python 3 (Christian Clauss) [#1937](https://github.com/nodejs/node-gyp/pull/1937)
+* [[`7cf507906d`](https://github.com/nodejs/node-gyp/commit/7cf507906d)] - **src,win**: allow 403 errors for arm64 node.lib (Richard Lau) [#1934](https://github.com/nodejs/node-gyp/pull/1934)
+* [[`ad0d182c01`](https://github.com/nodejs/node-gyp/commit/ad0d182c01)] - **deps**: update deps to roughly match current npm@6 (Rod Vagg) [#1920](https://github.com/nodejs/node-gyp/pull/1920)
+* [[`1553081ed6`](https://github.com/nodejs/node-gyp/commit/1553081ed6)] - **test**: upgrade Linux Travis CI to Python 3.8 (Christian Clauss) [#1923](https://github.com/nodejs/node-gyp/pull/1923)
+* [[`0705cae9aa`](https://github.com/nodejs/node-gyp/commit/0705cae9aa)] - **travis**: ignore failed `brew upgrade npm`, update xcode (Christian Clauss) [#1932](https://github.com/nodejs/node-gyp/pull/1932)
+* [[`7bfdb6f5bf`](https://github.com/nodejs/node-gyp/commit/7bfdb6f5bf)] - **build**: avoid bare exceptions in xcode\_emulation.py (Christian Clauss) [#1932](https://github.com/nodejs/node-gyp/pull/1932)
+* [[`7edf7658fa`](https://github.com/nodejs/node-gyp/commit/7edf7658fa)] - **lib,install**: always download SHA sums on Windows (Sam Hughes) [#1926](https://github.com/nodejs/node-gyp/pull/1926)
+* [[`69056d04fe`](https://github.com/nodejs/node-gyp/commit/69056d04fe)] - **travis**: add Windows + Python 3.8 to the mix (Rod Vagg) [#1921](https://github.com/nodejs/node-gyp/pull/1921)
+
+## v5.0.5 2019-10-04
+
+* [[`3891391746`](https://github.com/nodejs/node-gyp/commit/3891391746)] - **doc**: reconcile README with Python 3 compat changes (Rod Vagg) [#1911](https://github.com/nodejs/node-gyp/pull/1911)
+* [[`07f81f1920`](https://github.com/nodejs/node-gyp/commit/07f81f1920)] - **lib**: accept Python 3 after Python 2 (Sam Roberts) [#1910](https://github.com/nodejs/node-gyp/pull/1910)
+* [[`04ce59f4a2`](https://github.com/nodejs/node-gyp/commit/04ce59f4a2)] - **doc**: clarify Python configuration, etc (Sam Roberts) [#1908](https://github.com/nodejs/node-gyp/pull/1908)
+* [[`01c46ee3df`](https://github.com/nodejs/node-gyp/commit/01c46ee3df)] - **gyp**: add \_\_lt\_\_ to MSVSSolutionEntry (João Reis) [#1904](https://github.com/nodejs/node-gyp/pull/1904)
+* [[`735d961b99`](https://github.com/nodejs/node-gyp/commit/735d961b99)] - **win**: support VS 2017 Desktop Express (João Reis) [#1902](https://github.com/nodejs/node-gyp/pull/1902)
+* [[`3834156a92`](https://github.com/nodejs/node-gyp/commit/3834156a92)] - **test**: add Python 3.5 and 3.6 tests on Linux (cclauss) [#1909](https://github.com/nodejs/node-gyp/pull/1909)
+* [[`1196e990d8`](https://github.com/nodejs/node-gyp/commit/1196e990d8)] - **src**: update to standard@14 (Rod Vagg) [#1899](https://github.com/nodejs/node-gyp/pull/1899)
+* [[`53ee7dfe89`](https://github.com/nodejs/node-gyp/commit/53ee7dfe89)] - **gyp**: fix undefined name: cflags --\> ldflags (Christian Clauss) [#1901](https://github.com/nodejs/node-gyp/pull/1901)
+* [[`5871dcf6c9`](https://github.com/nodejs/node-gyp/commit/5871dcf6c9)] - **src,win**: add support for fetching arm64 node.lib (Richard Townsend) [#1875](https://github.com/nodejs/node-gyp/pull/1875)
+
+## v5.0.4 2019-09-27
+
+* [[`1236869ffc`](https://github.com/nodejs/node-gyp/commit/1236869ffc)] - **gyp**: modify XcodeVersion() to convert "4.2" to "0420" and "10.0" to "1000" (Christian Clauss) [#1895](https://github.com/nodejs/node-gyp/pull/1895)
+* [[`36638afe48`](https://github.com/nodejs/node-gyp/commit/36638afe48)] - **gyp**: more decode stdout on Python 3 (cclauss) [#1894](https://github.com/nodejs/node-gyp/pull/1894)
+* [[`f753c167c5`](https://github.com/nodejs/node-gyp/commit/f753c167c5)] - **gyp**: decode stdout on Python 3 (cclauss) [#1890](https://github.com/nodejs/node-gyp/pull/1890)
+* [[`60a4083523`](https://github.com/nodejs/node-gyp/commit/60a4083523)] - **doc**: update xcode install instructions to match Node's BUILDING (Nhan Khong) [#1884](https://github.com/nodejs/node-gyp/pull/1884)
+* [[`19dbc9ac32`](https://github.com/nodejs/node-gyp/commit/19dbc9ac32)] - **deps**: update tar to 4.4.12 (Matheus Marchini) [#1889](https://github.com/nodejs/node-gyp/pull/1889)
+* [[`5f3ed92181`](https://github.com/nodejs/node-gyp/commit/5f3ed92181)] - **bin**: fix the usage instructions (Halit Ogunc) [#1888](https://github.com/nodejs/node-gyp/pull/1888)
+* [[`aab118edf1`](https://github.com/nodejs/node-gyp/commit/aab118edf1)] - **lib**: adding keep-alive header to download requests (Milad Farazmand) [#1863](https://github.com/nodejs/node-gyp/pull/1863)
+* [[`1186e89326`](https://github.com/nodejs/node-gyp/commit/1186e89326)] - **lib**: ignore non-critical os.userInfo() failures (Rod Vagg) [#1835](https://github.com/nodejs/node-gyp/pull/1835)
+* [[`785e527c3d`](https://github.com/nodejs/node-gyp/commit/785e527c3d)] - **doc**: fix missing argument for setting python path (lagorsse) [#1802](https://github.com/nodejs/node-gyp/pull/1802)
+* [[`a97615196c`](https://github.com/nodejs/node-gyp/commit/a97615196c)] - **gyp**: rm semicolons (Python != JavaScript) (MattIPv4) [#1858](https://github.com/nodejs/node-gyp/pull/1858)
+* [[`06019bac24`](https://github.com/nodejs/node-gyp/commit/06019bac24)] - **gyp**: assorted typo fixes (XhmikosR) [#1853](https://github.com/nodejs/node-gyp/pull/1853)
+* [[`3f4972c1ca`](https://github.com/nodejs/node-gyp/commit/3f4972c1ca)] - **gyp**: use "is" when comparing to None (Vladyslav Burzakovskyy) [#1860](https://github.com/nodejs/node-gyp/pull/1860)
+* [[`1cb4708073`](https://github.com/nodejs/node-gyp/commit/1cb4708073)] - **src,win**: improve unmanaged handling (Peter Sabath) [#1852](https://github.com/nodejs/node-gyp/pull/1852)
+* [[`5553cd910e`](https://github.com/nodejs/node-gyp/commit/5553cd910e)] - **gyp**: improve Windows+Cygwin compatibility (Jose Quijada) [#1817](https://github.com/nodejs/node-gyp/pull/1817)
+* [[`8bcb1fbb43`](https://github.com/nodejs/node-gyp/commit/8bcb1fbb43)] - **gyp**: Python 3 Windows fixes (João Reis) [#1843](https://github.com/nodejs/node-gyp/pull/1843)
+* [[`2e24d0a326`](https://github.com/nodejs/node-gyp/commit/2e24d0a326)] - **test**: accept Python 3 in test-find-python.js (João Reis) [#1843](https://github.com/nodejs/node-gyp/pull/1843)
+* [[`1267b4dc1c`](https://github.com/nodejs/node-gyp/commit/1267b4dc1c)] - **build**: add test run Python 3.7 on macOS (Christian Clauss) [#1843](https://github.com/nodejs/node-gyp/pull/1843)
+* [[`da1b031aa3`](https://github.com/nodejs/node-gyp/commit/da1b031aa3)] - **build**: import StringIO on Python 2 and Python 3 (Christian Clauss) [#1836](https://github.com/nodejs/node-gyp/pull/1836)
+* [[`fa0ed4aa42`](https://github.com/nodejs/node-gyp/commit/fa0ed4aa42)] - **build**: more Python 3 compat, replace compile with ast (cclauss) [#1820](https://github.com/nodejs/node-gyp/pull/1820)
+* [[`18d5c7c9d0`](https://github.com/nodejs/node-gyp/commit/18d5c7c9d0)] - **win,src**: update win\_delay\_load\_hook.cc to work with /clr (Ivan Petrovic) [#1819](https://github.com/nodejs/node-gyp/pull/1819)
+
+## v5.0.3 2019-07-17
+
+* [[`66ad305775`](https://github.com/nodejs/node-gyp/commit/66ad305775)] - **python**: accept Python 3 conditionally (João Reis) [#1815](https://github.com/nodejs/node-gyp/pull/1815)
+* [[`7e7fce3fed`](https://github.com/nodejs/node-gyp/commit/7e7fce3fed)] - **python**: move Python detection to its own file (João Reis) [#1815](https://github.com/nodejs/node-gyp/pull/1815)
+* [[`e40c99e283`](https://github.com/nodejs/node-gyp/commit/e40c99e283)] - **src**: implement standard.js linting (Rod Vagg) [#1794](https://github.com/nodejs/node-gyp/pull/1794)
+* [[`bb92c761a9`](https://github.com/nodejs/node-gyp/commit/bb92c761a9)] - **test**: add Node.js 6 on Windows to Travis CI (João Reis) [#1812](https://github.com/nodejs/node-gyp/pull/1812)
+* [[`7fd924079f`](https://github.com/nodejs/node-gyp/commit/7fd924079f)] - **test**: increase tap timeout (João Reis) [#1812](https://github.com/nodejs/node-gyp/pull/1812)
+* [[`7e8127068f`](https://github.com/nodejs/node-gyp/commit/7e8127068f)] - **test**: cover supported node versions with travis (Rod Vagg) [#1809](https://github.com/nodejs/node-gyp/pull/1809)
+* [[`24109148df`](https://github.com/nodejs/node-gyp/commit/24109148df)] - **test**: downgrade to tap@^12 for continued Node 6 support (Rod Vagg) [#1808](https://github.com/nodejs/node-gyp/pull/1808)
+* [[`656117cc4a`](https://github.com/nodejs/node-gyp/commit/656117cc4a)] - **win**: make VS path match case-insensitive (João Reis) [#1806](https://github.com/nodejs/node-gyp/pull/1806)
+
+## v5.0.2 2019-06-27
+
+* [[`2761afbf73`](https://github.com/nodejs/node-gyp/commit/2761afbf73)] - **build,test**: add duplicate symbol test (Gabriel Schulhof) [#1689](https://github.com/nodejs/node-gyp/pull/1689)
+* [[`82f129d6de`](https://github.com/nodejs/node-gyp/commit/82f129d6de)] - **gyp**: replace optparse to argparse (KiYugadgeter) [#1591](https://github.com/nodejs/node-gyp/pull/1591)
+* [[`afaaa29c61`](https://github.com/nodejs/node-gyp/commit/afaaa29c61)] - **gyp**: remove from \_\_future\_\_ import with\_statement (cclauss) [#1799](https://github.com/nodejs/node-gyp/pull/1799)
+* [[`a991f633d6`](https://github.com/nodejs/node-gyp/commit/a991f633d6)] - **gyp**: fix the remaining Python 3 issues (cclauss) [#1793](https://github.com/nodejs/node-gyp/pull/1793)
+* [[`f952b08f84`](https://github.com/nodejs/node-gyp/commit/f952b08f84)] - **gyp**: move from \_\_future\_\_ import to the top of the file (cclauss) [#1789](https://github.com/nodejs/node-gyp/pull/1789)
+* [[`4f4a677dfa`](https://github.com/nodejs/node-gyp/commit/4f4a677dfa)] - **gyp**: use different default compiler for z/OS (Shuowang (Wayne) Zhang) [#1768](https://github.com/nodejs/node-gyp/pull/1768)
+* [[`03683f09d6`](https://github.com/nodejs/node-gyp/commit/03683f09d6)] - **lib**: code de-duplication (Pavel Medvedev) [#965](https://github.com/nodejs/node-gyp/pull/965)
+* [[`611bc3c89f`](https://github.com/nodejs/node-gyp/commit/611bc3c89f)] - **lib**: add .json suffix for explicit require (Rod Vagg) [#1787](https://github.com/nodejs/node-gyp/pull/1787)
+* [[`d3478d7b0b`](https://github.com/nodejs/node-gyp/commit/d3478d7b0b)] - **meta**: add to .gitignore (Refael Ackermann) [#1573](https://github.com/nodejs/node-gyp/pull/1573)
+* [[`7a9a038e9e`](https://github.com/nodejs/node-gyp/commit/7a9a038e9e)] - **test**: add parallel test runs on macOS and Windows (cclauss) [#1800](https://github.com/nodejs/node-gyp/pull/1800)
+* [[`7dd7f2b2a2`](https://github.com/nodejs/node-gyp/commit/7dd7f2b2a2)] - **test**: fix Python syntax error in test-adding.js (cclauss) [#1793](https://github.com/nodejs/node-gyp/pull/1793)
+* [[`395f843de0`](https://github.com/nodejs/node-gyp/commit/395f843de0)] - **test**: replace self-signed cert with 'localhost' (Rod Vagg) [#1795](https://github.com/nodejs/node-gyp/pull/1795)
+* [[`a52c6eb9e8`](https://github.com/nodejs/node-gyp/commit/a52c6eb9e8)] - **test**: migrate from tape to tap (Rod Vagg) [#1795](https://github.com/nodejs/node-gyp/pull/1795)
+* [[`ec2eb44a30`](https://github.com/nodejs/node-gyp/commit/ec2eb44a30)] - **test**: use Nan in duplicate\_symbols (Gabriel Schulhof) [#1689](https://github.com/nodejs/node-gyp/pull/1689)
+* [[`1597c84aad`](https://github.com/nodejs/node-gyp/commit/1597c84aad)] - **test**: use Travis CI to run tests on every pull request (cclauss) [#1752](https://github.com/nodejs/node-gyp/pull/1752)
+* [[`dd9bf929ac`](https://github.com/nodejs/node-gyp/commit/dd9bf929ac)] - **zos**: update compiler options (Shuowang (Wayne) Zhang) [#1768](https://github.com/nodejs/node-gyp/pull/1768)
+
+## v5.0.1 2019-06-20
+
+* [[`e3861722ed`](https://github.com/nodejs/node-gyp/commit/e3861722ed)] - **doc**: document --jobs max (David Sanders) [#1770](https://github.com/nodejs/node-gyp/pull/1770)
+* [[`1cfdb28886`](https://github.com/nodejs/node-gyp/commit/1cfdb28886)] - **lib**: reintroduce support for iojs file naming for releases \>= 1 && \< 4 (Samuel Attard) [#1777](https://github.com/nodejs/node-gyp/pull/1777)
+
+## v5.0.0 2019-06-13
+
+* [[`8a83972743`](https://github.com/nodejs/node-gyp/commit/8a83972743)] - **(SEMVER-MAJOR)** **bin**: follow XDG OS conventions for storing data (Selwyn) [#1570](https://github.com/nodejs/node-gyp/pull/1570)
+* [[`9e46872ea3`](https://github.com/nodejs/node-gyp/commit/9e46872ea3)] - **bin,lib**: remove extra comments/lines/spaces (Jon Moss) [#1508](https://github.com/nodejs/node-gyp/pull/1508)
+* [[`8098ebdeb4`](https://github.com/nodejs/node-gyp/commit/8098ebdeb4)] - **deps**: replace `osenv` dependency with native `os` (Selwyn)
+* [[`f83b457e03`](https://github.com/nodejs/node-gyp/commit/f83b457e03)] - **deps**: bump request to 2.8.7, fixes heok/hawk issues (Rohit Hazra) [#1492](https://github.com/nodejs/node-gyp/pull/1492)
+* [[`323cee7323`](https://github.com/nodejs/node-gyp/commit/323cee7323)] - **deps**: pin `request` version range (Refael Ackermann) [#1300](https://github.com/nodejs/node-gyp/pull/1300)
+* [[`c515912d08`](https://github.com/nodejs/node-gyp/commit/c515912d08)] - **doc**: improve issue template (Bartosz Sosnowski) [#1618](https://github.com/nodejs/node-gyp/pull/1618)
+* [[`cca2d66727`](https://github.com/nodejs/node-gyp/commit/cca2d66727)] - **doc**: python info needs own header (Taylor D. Lee) [#1245](https://github.com/nodejs/node-gyp/pull/1245)
+* [[`3e64c780f5`](https://github.com/nodejs/node-gyp/commit/3e64c780f5)] - **doc**: lint README.md (Jon Moss) [#1498](https://github.com/nodejs/node-gyp/pull/1498)
+* [[`a20faedc91`](https://github.com/nodejs/node-gyp/commit/a20faedc91)] - **(SEMVER-MAJOR)** **gyp**: enable MARMASM items only on new VS versions (João Reis) [#1762](https://github.com/nodejs/node-gyp/pull/1762)
+* [[`721eb691cf`](https://github.com/nodejs/node-gyp/commit/721eb691cf)] - **gyp**: teach MSVS generator about MARMASM Items (Jon Kunkee) [#1679](https://github.com/nodejs/node-gyp/pull/1679)
+* [[`91744bfecc`](https://github.com/nodejs/node-gyp/commit/91744bfecc)] - **gyp**: add support for Windows on Arm (Richard Townsend) [#1739](https://github.com/nodejs/node-gyp/pull/1739)
+* [[`a6e0a6c7ed`](https://github.com/nodejs/node-gyp/commit/a6e0a6c7ed)] - **gyp**: move compile\_commands\_json (Paul Maréchal) [#1661](https://github.com/nodejs/node-gyp/pull/1661)
+* [[`92e8b52cee`](https://github.com/nodejs/node-gyp/commit/92e8b52cee)] - **gyp**: fix target --\> self.target (cclauss)
+* [[`febdfa2137`](https://github.com/nodejs/node-gyp/commit/febdfa2137)] - **gyp**: fix sntex error (cclauss) [#1333](https://github.com/nodejs/node-gyp/pull/1333)
+* [[`588d333c14`](https://github.com/nodejs/node-gyp/commit/588d333c14)] - **gyp**: \_winreg module was renamed to winreg in Python 3. (Craig Rodrigues)
+* [[`98226d198c`](https://github.com/nodejs/node-gyp/commit/98226d198c)] - **gyp**: replace basestring with str, but only on Python 3. (Craig Rodrigues)
+* [[`7535e4478e`](https://github.com/nodejs/node-gyp/commit/7535e4478e)] - **gyp**: replace deprecated functions (Craig Rodrigues)
+* [[`2040cd21cc`](https://github.com/nodejs/node-gyp/commit/2040cd21cc)] - **gyp**: use print as a function, as specified in PEP 3105. (Craig Rodrigues)
+* [[`abef93ded5`](https://github.com/nodejs/node-gyp/commit/abef93ded5)] - **gyp**: get ready for python 3 (cclauss)
+* [[`43031fadcb`](https://github.com/nodejs/node-gyp/commit/43031fadcb)] - **python**: clean-up detection (João Reis) [#1582](https://github.com/nodejs/node-gyp/pull/1582)
+* [[`49ab79d221`](https://github.com/nodejs/node-gyp/commit/49ab79d221)] - **python**: more informative error (Refael Ackermann) [#1269](https://github.com/nodejs/node-gyp/pull/1269)
+* [[`997bc3c748`](https://github.com/nodejs/node-gyp/commit/997bc3c748)] - **readme**: add ARM64 info to MSVC setup instructions (Jon Kunkee) [#1655](https://github.com/nodejs/node-gyp/pull/1655)
+* [[`788e767179`](https://github.com/nodejs/node-gyp/commit/788e767179)] - **test**: remove unused variable (João Reis)
+* [[`6f5a408934`](https://github.com/nodejs/node-gyp/commit/6f5a408934)] - **tools**: fix usage of inherited -fPIC and -fPIE (Jens) [#1340](https://github.com/nodejs/node-gyp/pull/1340)
+* [[`0efb8fb34b`](https://github.com/nodejs/node-gyp/commit/0efb8fb34b)] - **(SEMVER-MAJOR)** **win**: support running in VS Command Prompt (João Reis) [#1762](https://github.com/nodejs/node-gyp/pull/1762)
+* [[`360ddbdf3a`](https://github.com/nodejs/node-gyp/commit/360ddbdf3a)] - **(SEMVER-MAJOR)** **win**: add support for Visual Studio 2019 (João Reis) [#1762](https://github.com/nodejs/node-gyp/pull/1762)
+* [[`8f43f68275`](https://github.com/nodejs/node-gyp/commit/8f43f68275)] - **(SEMVER-MAJOR)** **win**: detect all VS versions in node-gyp (João Reis) [#1762](https://github.com/nodejs/node-gyp/pull/1762)
+* [[`7fe4095974`](https://github.com/nodejs/node-gyp/commit/7fe4095974)] - **(SEMVER-MAJOR)** **win**: generic Visual Studio 2017 detection (João Reis) [#1762](https://github.com/nodejs/node-gyp/pull/1762)
+* [[`7a71d68bce`](https://github.com/nodejs/node-gyp/commit/7a71d68bce)] - **win**: use msbuild from the configure stage (Bartosz Sosnowski) [#1654](https://github.com/nodejs/node-gyp/pull/1654)
+* [[`d3b21220a0`](https://github.com/nodejs/node-gyp/commit/d3b21220a0)] - **win**: fix delay-load hook for electron 4 (Andy Dill)
+* [[`81f3a92338`](https://github.com/nodejs/node-gyp/commit/81f3a92338)] - Update list of Node.js versions to test against. (Ben Noordhuis) [#1670](https://github.com/nodejs/node-gyp/pull/1670)
+* [[`4748f6ab75`](https://github.com/nodejs/node-gyp/commit/4748f6ab75)] - Remove deprecated compatibility code. (Ben Noordhuis) [#1670](https://github.com/nodejs/node-gyp/pull/1670)
+* [[`45e3221fd4`](https://github.com/nodejs/node-gyp/commit/45e3221fd4)] - Remove an outdated workaround for Python 2.4 (cclauss) [#1650](https://github.com/nodejs/node-gyp/pull/1650)
+* [[`721dc7d314`](https://github.com/nodejs/node-gyp/commit/721dc7d314)] - Add ARM64 to MSBuild /Platform logic (Jon Kunkee) [#1655](https://github.com/nodejs/node-gyp/pull/1655)
+* [[`a5b7410497`](https://github.com/nodejs/node-gyp/commit/a5b7410497)] - Add ESLint no-unused-vars rule (Jon Moss) [#1497](https://github.com/nodejs/node-gyp/pull/1497)
+
+## v4.0.0 2019-04-24
+
+* [[`ceed5cbe10`](https://github.com/nodejs/node-gyp/commit/ceed5cbe10)] - **deps**: updated tar package version to 4.4.8 (Pobegaylo Maksim) [#1713](https://github.com/nodejs/node-gyp/pull/1713)
+* [[`374519e066`](https://github.com/nodejs/node-gyp/commit/374519e066)] - **(SEMVER-MAJOR)** Upgrade to tar v3 (isaacs) [#1212](https://github.com/nodejs/node-gyp/pull/1212)
+* [[`e6699d13cd`](https://github.com/nodejs/node-gyp/commit/e6699d13cd)] - **test**: fix addon test for Node.js 12 and V8 7.4 (Richard Lau) [#1705](https://github.com/nodejs/node-gyp/pull/1705)
+* [[`0c6bf530a0`](https://github.com/nodejs/node-gyp/commit/0c6bf530a0)] - **lib**: use print() for python version detection (GreenAddress) [#1534](https://github.com/nodejs/node-gyp/pull/1534)
+
+## v3.8.0 2018-08-09
+
+* [[`c5929cb4fe`](https://github.com/nodejs/node-gyp/commit/c5929cb4fe)] - **doc**: update Xcode preferences tab name. (Ivan Daniluk) [#1330](https://github.com/nodejs/node-gyp/pull/1330)
+* [[`8b488da8b9`](https://github.com/nodejs/node-gyp/commit/8b488da8b9)] - **doc**: update link to commit guidelines (Jonas Hermsmeier) [#1456](https://github.com/nodejs/node-gyp/pull/1456)
+* [[`b4fe8c16f9`](https://github.com/nodejs/node-gyp/commit/b4fe8c16f9)] - **doc**: fix visual studio links (Bartosz Sosnowski) [#1490](https://github.com/nodejs/node-gyp/pull/1490)
+* [[`536759c7e9`](https://github.com/nodejs/node-gyp/commit/536759c7e9)] - **configure**: use sys.version\_info to get python version (Yang Guo) [#1504](https://github.com/nodejs/node-gyp/pull/1504)
+* [[`94c39c604e`](https://github.com/nodejs/node-gyp/commit/94c39c604e)] - **gyp**: fix ninja build failure (GYP patch) (Daniel Bevenius) [nodejs/node#12484](https://github.com/nodejs/node/pull/12484)
+* [[`e8ea74e0fa`](https://github.com/nodejs/node-gyp/commit/e8ea74e0fa)] - **tools**: patch gyp to avoid xcrun errors (Ujjwal Sharma) [nodejs/node#21520](https://github.com/nodejs/node/pull/21520)
+* [[`ea9aff44f2`](https://github.com/nodejs/node-gyp/commit/ea9aff44f2)] - **tools**: fix "the the" typos in comments (Masashi Hirano) [nodejs/node#20716](https://github.com/nodejs/node/pull/20716)
+* [[`207e5aa4fd`](https://github.com/nodejs/node-gyp/commit/207e5aa4fd)] - **gyp**: implement LD/LDXX for ninja and FIPS (Sam Roberts) 
+* [[`b416c5f4b7`](https://github.com/nodejs/node-gyp/commit/b416c5f4b7)] - **gyp**: enable cctest to use objects (gyp part) (Daniel Bevenius) [nodejs/node#12450](https://github.com/nodejs/node/pull/12450)
+* [[`40692d016b`](https://github.com/nodejs/node-gyp/commit/40692d016b)] - **gyp**: add compile\_commands.json gyp generator (Ben Noordhuis) [nodejs/node#12450](https://github.com/nodejs/node/pull/12450)
+* [[`fc3c4e2b10`](https://github.com/nodejs/node-gyp/commit/fc3c4e2b10)] - **gyp**: float gyp patch for long filenames (Anna Henningsen) [nodejs/node#7963](https://github.com/nodejs/node/pull/7963)
+* [[`8aedbfdef6`](https://github.com/nodejs/node-gyp/commit/8aedbfdef6)] - **gyp**: backport GYP fix to fix AIX shared suffix (Stewart Addison) 
+* [[`6cd84b84fc`](https://github.com/nodejs/node-gyp/commit/6cd84b84fc)] - **test**: formatting and minor fixes for execFileSync replacement (Rod Vagg) [#1521](https://github.com/nodejs/node-gyp/pull/1521)
+* [[`60e421363f`](https://github.com/nodejs/node-gyp/commit/60e421363f)] - **test**: added test/processExecSync.js for when execFileSync is not available. (Rohit Hazra) [#1492](https://github.com/nodejs/node-gyp/pull/1492)
+* [[`969447c5bd`](https://github.com/nodejs/node-gyp/commit/969447c5bd)] - **deps**: bump request to 2.8.7, fixes heok/hawk issues (Rohit Hazra) [#1492](https://github.com/nodejs/node-gyp/pull/1492)
+* [[`340403ccfe`](https://github.com/nodejs/node-gyp/commit/340403ccfe)] - **win**: improve parsing of SDK version (Alessandro Vergani) [#1516](https://github.com/nodejs/node-gyp/pull/1516)
+
+## v3.7.0 2018-06-08
+
+* [[`84cea7b30d`](https://github.com/nodejs/node-gyp/commit/84cea7b30d)] - Remove unused gyp test scripts. (Ben Noordhuis) [#1458](https://github.com/nodejs/node-gyp/pull/1458)
+* [[`0540e4ec63`](https://github.com/nodejs/node-gyp/commit/0540e4ec63)] - **gyp**: escape spaces in filenames in make generator (Jeff Senn) [#1436](https://github.com/nodejs/node-gyp/pull/1436)
+* [[`88fc6fa0ec`](https://github.com/nodejs/node-gyp/commit/88fc6fa0ec)] - Drop dependency on minimatch. (Brian Woodward) [#1158](https://github.com/nodejs/node-gyp/pull/1158)
+* [[`1e203c5148`](https://github.com/nodejs/node-gyp/commit/1e203c5148)] - Fix include path when pointing to Node.js source (Richard Lau) [#1055](https://github.com/nodejs/node-gyp/pull/1055)
+* [[`53d8cb967c`](https://github.com/nodejs/node-gyp/commit/53d8cb967c)] - Prefix build targets with /t: on Windows (Natalie Wolfe) [#1164](https://github.com/nodejs/node-gyp/pull/1164)
+* [[`53a5f8ff38`](https://github.com/nodejs/node-gyp/commit/53a5f8ff38)] - **gyp**: add support for .mm files to msvs generator (Julien Racle) [#1167](https://github.com/nodejs/node-gyp/pull/1167)
+* [[`dd8561e528`](https://github.com/nodejs/node-gyp/commit/dd8561e528)] - **zos**: don't use universal-new-lines mode (John Barboza) [#1451](https://github.com/nodejs/node-gyp/pull/1451)
+* [[`e5a69010ed`](https://github.com/nodejs/node-gyp/commit/e5a69010ed)] - **zos**: add search locations for libnode.x (John Barboza) [#1451](https://github.com/nodejs/node-gyp/pull/1451)
+* [[`79febace53`](https://github.com/nodejs/node-gyp/commit/79febace53)] - **doc**: update macOS information in README (Josh Parnham) [#1323](https://github.com/nodejs/node-gyp/pull/1323)
+* [[`9425448945`](https://github.com/nodejs/node-gyp/commit/9425448945)] - **gyp**: don't print xcodebuild not found errors (Gibson Fahnestock) [#1370](https://github.com/nodejs/node-gyp/pull/1370)
+* [[`6f1286f5b2`](https://github.com/nodejs/node-gyp/commit/6f1286f5b2)] - Fix infinite install loop. (Ben Noordhuis) [#1384](https://github.com/nodejs/node-gyp/pull/1384)
+* [[`2580b9139e`](https://github.com/nodejs/node-gyp/commit/2580b9139e)] - Update `--nodedir` description in README. (Ben Noordhuis) [#1372](https://github.com/nodejs/node-gyp/pull/1372)
+* [[`a61360391a`](https://github.com/nodejs/node-gyp/commit/a61360391a)] - Update README with another way to install on windows (JeffAtDeere) [#1352](https://github.com/nodejs/node-gyp/pull/1352)
+* [[`47496bf6dc`](https://github.com/nodejs/node-gyp/commit/47496bf6dc)] - Fix IndexError when parsing GYP files. (Ben Noordhuis) [#1267](https://github.com/nodejs/node-gyp/pull/1267)
+* [[`b2024dee7b`](https://github.com/nodejs/node-gyp/commit/b2024dee7b)] - **zos**: support platform (John Barboza) [#1276](https://github.com/nodejs/node-gyp/pull/1276)
+* [[`90d86512f4`](https://github.com/nodejs/node-gyp/commit/90d86512f4)] - **win**: run PS with `-NoProfile` (Refael Ackermann) [#1292](https://github.com/nodejs/node-gyp/pull/1292)
+* [[`2da5f86ef7`](https://github.com/nodejs/node-gyp/commit/2da5f86ef7)] - **doc**: add github PR and Issue templates (Gibson Fahnestock) [#1228](https://github.com/nodejs/node-gyp/pull/1228)
+* [[`a46a770d68`](https://github.com/nodejs/node-gyp/commit/a46a770d68)] - **doc**: update proposed DCO and CoC (Mikeal Rogers) [#1229](https://github.com/nodejs/node-gyp/pull/1229)
+* [[`7e803d58e0`](https://github.com/nodejs/node-gyp/commit/7e803d58e0)] - **doc**: headerify the Install instructions (Nick Schonning) [#1225](https://github.com/nodejs/node-gyp/pull/1225)
+* [[`f27599193a`](https://github.com/nodejs/node-gyp/commit/f27599193a)] - **gyp**: update xml string encoding conversion (Liu Chao) [#1203](https://github.com/nodejs/node-gyp/pull/1203)
+* [[`0a07e481f7`](https://github.com/nodejs/node-gyp/commit/0a07e481f7)] - **configure**: don't set ensure if tarball is set (Gibson Fahnestock) [#1220](https://github.com/nodejs/node-gyp/pull/1220)
+
+## v3.6.3 2018-06-08
+
+* [[`90cd2e8da9`](https://github.com/nodejs/node-gyp/commit/90cd2e8da9)] - **gyp**: fix regex to match multi-digit versions (Jonas Hermsmeier) [#1455](https://github.com/nodejs/node-gyp/pull/1455)
+* [[`7900122337`](https://github.com/nodejs/node-gyp/commit/7900122337)] - deps: pin `request` version range (Refael Ackerman) [#1300](https://github.com/nodejs/node-gyp/pull/1300)
+
+## v3.6.2 2017-06-01
+
+* [[`72afdd62cd`](https://github.com/nodejs/node-gyp/commit/72afdd62cd)] - **build**: rename copyNodeLib() to doBuild() (Liu Chao) [#1206](https://github.com/nodejs/node-gyp/pull/1206)
+* [[`bad903ac70`](https://github.com/nodejs/node-gyp/commit/bad903ac70)] - **win**: more robust parsing of SDK version (Refael Ackermann) [#1198](https://github.com/nodejs/node-gyp/pull/1198)
+* [[`241752f381`](https://github.com/nodejs/node-gyp/commit/241752f381)] - Log dist-url. (Ben Noordhuis) [#1170](https://github.com/nodejs/node-gyp/pull/1170)
+* [[`386746c7d1`](https://github.com/nodejs/node-gyp/commit/386746c7d1)] - **configure**: use full path in node_lib_file GYP var (Pavel Medvedev) [#964](https://github.com/nodejs/node-gyp/pull/964)
+* [[`0913b2dd99`](https://github.com/nodejs/node-gyp/commit/0913b2dd99)] - **build, win**: use target_arch to link with node.lib (Pavel Medvedev) [#964](https://github.com/nodejs/node-gyp/pull/964)
+* [[`c307b302f7`](https://github.com/nodejs/node-gyp/commit/c307b302f7)] - **doc**: blorb about setting `npm_config_OPTION_NAME` (Refael Ackermann) [#1185](https://github.com/nodejs/node-gyp/pull/1185)
+
+## v3.6.1 2017-04-30
+
+* [[`49801716c2`](https://github.com/nodejs/node-gyp/commit/49801716c2)] - **test**: fix test-find-python on v0.10.x buildbot. (Ben Noordhuis) [#1172](https://github.com/nodejs/node-gyp/pull/1172)
+* [[`a83a3801fc`](https://github.com/nodejs/node-gyp/commit/a83a3801fc)] - **test**: fix test/test-configure-python on AIX (Richard Lau) [#1131](https://github.com/nodejs/node-gyp/pull/1131)
+* [[`8a767145c9`](https://github.com/nodejs/node-gyp/commit/8a767145c9)] - **gyp**: Revert quote_cmd workaround (Kunal Pathak) [#1153](https://github.com/nodejs/node-gyp/pull/1153)
+* [[`c09cf7671e`](https://github.com/nodejs/node-gyp/commit/c09cf7671e)] - **doc**: add a note for using `configure` on Windows (Vse Mozhet Byt) [#1152](https://github.com/nodejs/node-gyp/pull/1152)
+* [[`da9cb5f411`](https://github.com/nodejs/node-gyp/commit/da9cb5f411)] - Delete superfluous .patch files. (Ben Noordhuis) [#1122](https://github.com/nodejs/node-gyp/pull/1122)
+
+## v3.6.0 2017-03-16
+
+* [[`ae141e1906`](https://github.com/nodejs/node-gyp/commit/ae141e1906)] - **win**: find and setup for VS2017 (Refael Ackermann) [#1130](https://github.com/nodejs/node-gyp/pull/1130)
+* [[`ec5fc36a80`](https://github.com/nodejs/node-gyp/commit/ec5fc36a80)] - Add support to build node.js with chakracore for ARM. (Kunal Pathak) [#873](https://github.com/nodejs/node-gyp/pull/873)
+* [[`a04ea3051a`](https://github.com/nodejs/node-gyp/commit/a04ea3051a)] - Add support to build node.js with chakracore. (Kunal Pathak) [#873](https://github.com/nodejs/node-gyp/pull/873)
+* [[`93d7fa83c8`](https://github.com/nodejs/node-gyp/commit/93d7fa83c8)] - Upgrade semver dependency. (Ben Noordhuis) [#1107](https://github.com/nodejs/node-gyp/pull/1107)
+* [[`ff9a6fadfd`](https://github.com/nodejs/node-gyp/commit/ff9a6fadfd)] - Update link of gyp as Google code is shutting down (Peter Dave Hello) [#1061](https://github.com/nodejs/node-gyp/pull/1061)
+
+## v3.5.0 2017-01-10
+
+* [[`762d19a39e`](https://github.com/nodejs/node-gyp/commit/762d19a39e)] - \[doc\] merge History.md and CHANGELOG.md (Rod Vagg) 
+* [[`80fc5c3d31`](https://github.com/nodejs/node-gyp/commit/80fc5c3d31)] - Fix deprecated dependency warning (Simone Primarosa) [#1069](https://github.com/nodejs/node-gyp/pull/1069)
+* [[`05c44944fd`](https://github.com/nodejs/node-gyp/commit/05c44944fd)] - Open the build file with universal-newlines mode (Guy Margalit) [#1053](https://github.com/nodejs/node-gyp/pull/1053)
+* [[`37ae7be114`](https://github.com/nodejs/node-gyp/commit/37ae7be114)] - Try python launcher when stock python is python 3. (Ben Noordhuis) [#992](https://github.com/nodejs/node-gyp/pull/992)
+* [[`e3778d9907`](https://github.com/nodejs/node-gyp/commit/e3778d9907)] - Add lots of findPython() tests. (Ben Noordhuis) [#992](https://github.com/nodejs/node-gyp/pull/992)
+* [[`afc766adf6`](https://github.com/nodejs/node-gyp/commit/afc766adf6)] - Unset executable bit for .bat files (Pavel Medvedev) [#969](https://github.com/nodejs/node-gyp/pull/969)
+* [[`ddac348991`](https://github.com/nodejs/node-gyp/commit/ddac348991)] - Use push on PYTHONPATH and add tests (Michael Hart) [#990](https://github.com/nodejs/node-gyp/pull/990)
+* [[`b182a19042`](https://github.com/nodejs/node-gyp/commit/b182a19042)] - ***Revert*** "add "path-array" dep" (Michael Hart) [#990](https://github.com/nodejs/node-gyp/pull/990)
+* [[`7c08b85c5a`](https://github.com/nodejs/node-gyp/commit/7c08b85c5a)] - ***Revert*** "**configure**: use "path-array" for PYTHONPATH" (Michael Hart) [#990](https://github.com/nodejs/node-gyp/pull/990)
+* [[`9c8d275526`](https://github.com/nodejs/node-gyp/commit/9c8d275526)] - Add --devdir flag. (Ben Noordhuis) [#916](https://github.com/nodejs/node-gyp/pull/916)
+* [[`f6eab1f9e4`](https://github.com/nodejs/node-gyp/commit/f6eab1f9e4)] - **doc**: add windows-build-tools to readme (Felix Rieseberg) [#970](https://github.com/nodejs/node-gyp/pull/970)
+
+## v3.4.0 2016-06-28
+
+* [[`ce5fd04e94`](https://github.com/nodejs/node-gyp/commit/ce5fd04e94)] - **deps**: update minimatch version (delphiactual) [#961](https://github.com/nodejs/node-gyp/pull/961)
+* [[`77383ddd85`](https://github.com/nodejs/node-gyp/commit/77383ddd85)] - Replace fs.accessSync call to fs.statSync (Richard Lau) [#955](https://github.com/nodejs/node-gyp/pull/955)
+* [[`0dba4bda57`](https://github.com/nodejs/node-gyp/commit/0dba4bda57)] - **test**: add simple addon test (Richard Lau) [#955](https://github.com/nodejs/node-gyp/pull/955)
+* [[`c4344b3889`](https://github.com/nodejs/node-gyp/commit/c4344b3889)] - **doc**: add --target option to README (Gibson Fahnestock) [#958](https://github.com/nodejs/node-gyp/pull/958)
+* [[`cc778e9215`](https://github.com/nodejs/node-gyp/commit/cc778e9215)] - Override BUILDING_UV_SHARED, BUILDING_V8_SHARED. (Ben Noordhuis) [#915](https://github.com/nodejs/node-gyp/pull/915)
+* [[`af35b2ad32`](https://github.com/nodejs/node-gyp/commit/af35b2ad32)] - Move VC++ Build Tools to Build Tools landing page. (Andrew Pardoe) [#953](https://github.com/nodejs/node-gyp/pull/953)
+* [[`f31482e226`](https://github.com/nodejs/node-gyp/commit/f31482e226)] - **win**: work around __pfnDliNotifyHook2 type change (Alexis Campailla) [#952](https://github.com/nodejs/node-gyp/pull/952)
+* [[`3df8222fa5`](https://github.com/nodejs/node-gyp/commit/3df8222fa5)] - Allow for npmlog@3.x (Rebecca Turner) [#950](https://github.com/nodejs/node-gyp/pull/950)
+* [[`a4fa07b390`](https://github.com/nodejs/node-gyp/commit/a4fa07b390)] - More verbose error on locating msbuild.exe failure. (Mateusz Jaworski) [#930](https://github.com/nodejs/node-gyp/pull/930)
+* [[`4ee31329e0`](https://github.com/nodejs/node-gyp/commit/4ee31329e0)] - **doc**: add command options to README.md (Gibson Fahnestock) [#937](https://github.com/nodejs/node-gyp/pull/937)
+* [[`c8c7ca86b9`](https://github.com/nodejs/node-gyp/commit/c8c7ca86b9)] - Add --silent option for zero output. (Gibson Fahnestock) [#937](https://github.com/nodejs/node-gyp/pull/937)
+* [[`ac29d23a7c`](https://github.com/nodejs/node-gyp/commit/ac29d23a7c)] - Upgrade to glob@7.0.3. (Ben Noordhuis) [#943](https://github.com/nodejs/node-gyp/pull/943)
+* [[`15fd56be3d`](https://github.com/nodejs/node-gyp/commit/15fd56be3d)] - Enable V8 deprecation warnings for native modules (Matt Loring) [#920](https://github.com/nodejs/node-gyp/pull/920)
+* [[`7f1c1b960c`](https://github.com/nodejs/node-gyp/commit/7f1c1b960c)] - **gyp**: improvements for android generator (Robert Chiras) [#935](https://github.com/nodejs/node-gyp/pull/935)
+* [[`088082766c`](https://github.com/nodejs/node-gyp/commit/088082766c)] - Update Windows install instructions (Sara Itani) [#867](https://github.com/nodejs/node-gyp/pull/867)
+* [[`625c1515f9`](https://github.com/nodejs/node-gyp/commit/625c1515f9)] - **gyp**: inherit CC/CXX for CC/CXX.host (Johan Bergström) [#908](https://github.com/nodejs/node-gyp/pull/908)
+* [[`3bcb1720e4`](https://github.com/nodejs/node-gyp/commit/3bcb1720e4)] - Add support for the Python launcher on Windows (Patrick Westerhoff) [#894](https://github.com/nodejs/node-gyp/pull/894
+
+## v3.3.1 2016-03-04
+
+* [[`a981ef847a`](https://github.com/nodejs/node-gyp/commit/a981ef847a)] - **gyp**: fix android generator (Robert Chiras) [#889](https://github.com/nodejs/node-gyp/pull/889)
+
+## v3.3.0 2016-02-16
+
+* [[`818d854a4d`](https://github.com/nodejs/node-gyp/commit/818d854a4d)] - Introduce NODEJS_ORG_MIRROR and IOJS_ORG_MIRROR (Rod Vagg) [#878](https://github.com/nodejs/node-gyp/pull/878)
+* [[`d1e4cc4b62`](https://github.com/nodejs/node-gyp/commit/d1e4cc4b62)] - **(SEMVER-MINOR)** Download headers tarball for ~0.12.10 || ~0.10.42 (Rod Vagg) [#877](https://github.com/nodejs/node-gyp/pull/877)
+* [[`6e28ad1bea`](https://github.com/nodejs/node-gyp/commit/6e28ad1bea)] - Allow for npmlog@2.x (Rebecca Turner) [#861](https://github.com/nodejs/node-gyp/pull/861)
+* [[`07371e5812`](https://github.com/nodejs/node-gyp/commit/07371e5812)] - Use -fPIC for NetBSD. (Marcin Cieślak) [#856](https://github.com/nodejs/node-gyp/pull/856)
+* [[`8c4b0ffa50`](https://github.com/nodejs/node-gyp/commit/8c4b0ffa50)] - **(SEMVER-MINOR)** Add --cafile command line option. (Ben Noordhuis) [#837](https://github.com/nodejs/node-gyp/pull/837)
+* [[`b3ad43498e`](https://github.com/nodejs/node-gyp/commit/b3ad43498e)] - **(SEMVER-MINOR)** Make download() function testable. (Ben Noordhuis) [#837](https://github.com/nodejs/node-gyp/pull/837)
+
+## v3.2.1 2015-12-03
+
+* [[`ab89b477c4`](https://github.com/nodejs/node-gyp/commit/ab89b477c4)] - Upgrade gyp to b3cef02. (Ben Noordhuis) [#831](https://github.com/nodejs/node-gyp/pull/831)
+* [[`90078ecb17`](https://github.com/nodejs/node-gyp/commit/90078ecb17)] - Define WIN32_LEAN_AND_MEAN conditionally. (Ben Noordhuis) [#824](https://github.com/nodejs/node-gyp/pull/824)
+
+## v3.2.0 2015-11-25
+
+* [[`268f1ca4c7`](https://github.com/nodejs/node-gyp/commit/268f1ca4c7)] - Use result of `which` when searching for python. (Refael Ackermann) [#668](https://github.com/nodejs/node-gyp/pull/668)
+* [[`817ed9bd78`](https://github.com/nodejs/node-gyp/commit/817ed9bd78)] - Add test for python executable search logic. (Ben Noordhuis) [#756](https://github.com/nodejs/node-gyp/pull/756)
+* [[`0e2dfda1f3`](https://github.com/nodejs/node-gyp/commit/0e2dfda1f3)] - Fix test/test-options when run through `npm test`. (Ben Noordhuis) [#755](https://github.com/nodejs/node-gyp/pull/755)
+* [[`9bfa0876b4`](https://github.com/nodejs/node-gyp/commit/9bfa0876b4)] - Add support for AIX (Michael Dawson) [#753](https://github.com/nodejs/node-gyp/pull/753)
+* [[`a8d441a0a2`](https://github.com/nodejs/node-gyp/commit/a8d441a0a2)] - Update README for Windows 10 support. (Jason Williams) [#766](https://github.com/nodejs/node-gyp/pull/766)
+* [[`d1d6015276`](https://github.com/nodejs/node-gyp/commit/d1d6015276)] - Update broken links and switch to HTTPS. (andrew morton) 
+
+## v3.1.0 2015-11-14
+
+* [[`9049241f91`](https://github.com/nodejs/node-gyp/commit/9049241f91)] - **gyp**: don't use links at all, just copy the files instead (Nathan Zadoks)
+* [[`8ef90348d1`](https://github.com/nodejs/node-gyp/commit/8ef90348d1)] - **gyp**: apply https://codereview.chromium.org/11361103/ (Nathan Rajlich)
+* [[`a2ed0df84e`](https://github.com/nodejs/node-gyp/commit/a2ed0df84e)] - **gyp**: always install into $PRODUCT_DIR (Nathan Rajlich)
+* [[`cc8b2fa83e`](https://github.com/nodejs/node-gyp/commit/cc8b2fa83e)] - Update gyp to b3cef02. (Imran Iqbal) [#781](https://github.com/nodejs/node-gyp/pull/781)
+* [[`f5d86eb84e`](https://github.com/nodejs/node-gyp/commit/f5d86eb84e)] - Update to tar@2.0.0. (Edgar Muentes) [#797](https://github.com/nodejs/node-gyp/pull/797)
+* [[`2ac7de02c4`](https://github.com/nodejs/node-gyp/commit/2ac7de02c4)] - Fix infinite loop with zero-length options. (Ben Noordhuis) [#745](https://github.com/nodejs/node-gyp/pull/745)
+* [[`101bed639b`](https://github.com/nodejs/node-gyp/commit/101bed639b)] - This platform value came from debian package, and now the value (Jérémy Lal) [#738](https://github.com/nodejs/node-gyp/pull/738)
+
+## v3.0.3 2015-09-14
+
+* [[`ad827cda30`](https://github.com/nodejs/node-gyp/commit/ad827cda30)] - tarballUrl global and && when checking for iojs (Lars-Magnus Skog) [#729](https://github.com/nodejs/node-gyp/pull/729)
+
+## v3.0.2 2015-09-12
+
+* [[`6e8c3bf3c6`](https://github.com/nodejs/node-gyp/commit/6e8c3bf3c6)] - add back support for passing additional cmdline args (Rod Vagg) [#723](https://github.com/nodejs/node-gyp/pull/723)
+* [[`ff82f2f3b9`](https://github.com/nodejs/node-gyp/commit/ff82f2f3b9)] - fixed broken link in docs to Visual Studio 2013 download (simon-p-r) [#722](https://github.com/nodejs/node-gyp/pull/722)
+
+## v3.0.1 2015-09-08
+
+* [[`846337e36b`](https://github.com/nodejs/node-gyp/commit/846337e36b)] - normalise versions for target == this comparison (Rod Vagg) [#716](https://github.com/nodejs/node-gyp/pull/716)
+
+## v3.0.0 2015-09-08
+
+* [[`9720d0373c`](https://github.com/nodejs/node-gyp/commit/9720d0373c)] - remove node_modules from tree (Rod Vagg) [#711](https://github.com/nodejs/node-gyp/pull/711)
+* [[`6dcf220db7`](https://github.com/nodejs/node-gyp/commit/6dcf220db7)] - test version major directly, don't use semver.satisfies() (Rod Vagg) [#711](https://github.com/nodejs/node-gyp/pull/711)
+* [[`938dd18d1c`](https://github.com/nodejs/node-gyp/commit/938dd18d1c)] - refactor for clarity, fix dist-url, add env var dist-url functionality (Rod Vagg) [#711](https://github.com/nodejs/node-gyp/pull/711)
+* [[`9e9df66a06`](https://github.com/nodejs/node-gyp/commit/9e9df66a06)] - use process.release, make aware of io.js & node v4 differences (Rod Vagg) [#711](https://github.com/nodejs/node-gyp/pull/711)
+* [[`1ea7ed01f4`](https://github.com/nodejs/node-gyp/commit/1ea7ed01f4)] - **deps**: update graceful-fs dependency to the latest (Sakthipriyan Vairamani) [#714](https://github.com/nodejs/node-gyp/pull/714)
+* [[`0fbc387b35`](https://github.com/nodejs/node-gyp/commit/0fbc387b35)] - Update repository URLs. (Ben Noordhuis) [#715](https://github.com/nodejs/node-gyp/pull/715)
+* [[`bbedb8868b`](https://github.com/nodejs/node-gyp/commit/bbedb8868b)] - **(SEMVER-MAJOR)** **win**: enable delay-load hook by default (Jeremiah Senkpiel) [#708](https://github.com/nodejs/node-gyp/pull/708)
+* [[`85ed107565`](https://github.com/nodejs/node-gyp/commit/85ed107565)] - Merge pull request #664 from othiym23/othiym23/allow-semver-5 (Nathan Rajlich)
+* [[`0c720d234c`](https://github.com/nodejs/node-gyp/commit/0c720d234c)] - allow semver@5 (Forrest L Norvell)
+
+## 2.0.2 / 2015-07-14
+
+  * Use HTTPS for dist url (#656, @SonicHedgehog)
+  * Merge pull request #648 from nevosegal/master
+  * Merge pull request #650 from magic890/patch-1
+  * Updated Installation section on README
+  * Updated link to gyp user documentation
+  * Fix download error message spelling (#643, @tomxtobin)
+  * Merge pull request #637 from lygstate/master
+  * Set NODE_GYP_DIR for addon.gypi to setting absolute path for
+    src/win_delay_load_hook.c, and fixes of the long relative path issue on Win32.
+    Fixes #636 (#637, @lygstate).
+
+## 2.0.1 / 2015-05-28
+
+  * configure: try/catch the semver range.test() call
+  * README: update for visual studio 2013 (#510, @samccone)
+
+## 2.0.0 / 2015-05-24
+
+  * configure: check for python2 executable by default, fallback to python
+  * configure: don't clobber existing $PYTHONPATH
+  * configure: use "path-array" for PYTHONPATH
+  * gyp: fix for non-acsii userprofile name on Windows
+  * gyp: always install into $PRODUCT_DIR
+  * gyp: apply https://codereview.chromium.org/11361103/
+  * gyp: don't use links at all, just copy the files instead
+  * gyp: update gyp to e1c8fcf7
+  * Updated README.md with updated Windows build info
+  * Show URL when a download fails
+  * package: add a "license" field
+  * move HMODULE m declaration to top
+  * Only add "-undefined dynamic_lookup" to loadable_module targets
+  * win: optionally allow node.exe/iojs.exe to be renamed
+  * Avoid downloading shasums if using tarPath
+  * Add target name preprocessor define: `NODE_GYP_MODULE_NAME`
+  * Show better error message in case of bad network settings
diff --git a/server/node_modules/node-gyp/CONTRIBUTING.md b/server/node_modules/node-gyp/CONTRIBUTING.md
new file mode 100644
index 0000000..c1c50ea
--- /dev/null
+++ b/server/node_modules/node-gyp/CONTRIBUTING.md
@@ -0,0 +1,34 @@
+# Contributing to node-gyp
+
+## Code of Conduct
+
+Please read the
+[Code of Conduct](https://github.com/nodejs/admin/blob/master/CODE_OF_CONDUCT.md)
+which explains the minimum behavior expectations for node-gyp contributors.
+
+<a id="developers-certificate-of-origin"></a>
+## Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+* (a) The contribution was created in whole or in part by me and I
+  have the right to submit it under the open source license
+  indicated in the file; or
+
+* (b) The contribution is based upon previous work that, to the best
+  of my knowledge, is covered under an appropriate open source
+  license and I have the right under that license to submit that
+  work with modifications, whether created in whole or in part
+  by me, under the same open source license (unless I am
+  permitted to submit under a different license), as indicated
+  in the file; or
+
+* (c) The contribution was provided directly to me by some other
+  person who certified (a), (b) or (c) and I have not modified
+  it.
+
+* (d) I understand and agree that this project and the contribution
+  are public and that a record of the contribution (including all
+  personal information I submit with it, including my sign-off) is
+  maintained indefinitely and may be redistributed consistent with
+  this project or the open source license(s) involved.
diff --git a/server/node_modules/node-gyp/LICENSE b/server/node_modules/node-gyp/LICENSE
new file mode 100644
index 0000000..2ea4dc5
--- /dev/null
+++ b/server/node_modules/node-gyp/LICENSE
@@ -0,0 +1,24 @@
+(The MIT License)
+
+Copyright (c) 2012 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/node-gyp/README.md b/server/node_modules/node-gyp/README.md
new file mode 100644
index 0000000..71eea0a
--- /dev/null
+++ b/server/node_modules/node-gyp/README.md
@@ -0,0 +1,256 @@
+# `node-gyp` - Node.js native addon build tool
+
+[![Build Status](https://github.com/nodejs/node-gyp/workflows/Tests/badge.svg?branch=master)](https://github.com/nodejs/node-gyp/actions?query=workflow%3ATests+branch%3Amaster)
+![npm](https://img.shields.io/npm/dm/node-gyp)
+
+`node-gyp` is a cross-platform command-line tool written in Node.js for
+compiling native addon modules for Node.js. It contains a vendored copy of the
+[gyp-next](https://github.com/nodejs/gyp-next) project that was previously used
+by the Chromium team, extended to support the development of Node.js native addons.
+
+Note that `node-gyp` is _not_ used to build Node.js itself.
+
+Multiple target versions of Node.js are supported (i.e. `0.8`, ..., `4`, `5`, `6`,
+etc.), regardless of what version of Node.js is actually installed on your system
+(`node-gyp` downloads the necessary development files or headers for the target version).
+
+## Features
+
+ * The same build commands work on any of the supported platforms
+ * Supports the targeting of different versions of Node.js
+
+## Installation
+
+You can install `node-gyp` using `npm`:
+
+``` bash
+npm install -g node-gyp
+```
+
+Depending on your operating system, you will need to install:
+
+### On Unix
+
+   * Python v3.6, v3.7, v3.8, or v3.9
+   * `make`
+   * A proper C/C++ compiler toolchain, like [GCC](https://gcc.gnu.org)
+
+### On macOS
+
+**ATTENTION**: If your Mac has been _upgraded_ to macOS Catalina (10.15), please read [macOS_Catalina.md](macOS_Catalina.md).
+
+   * Python v3.6, v3.7, v3.8, or v3.9
+   * [Xcode](https://developer.apple.com/xcode/download/)
+     * You also need to install the `XCode Command Line Tools` by running `xcode-select --install`. Alternatively, if you already have the full Xcode installed, you can find them under the menu `Xcode -> Open Developer Tool -> More Developer Tools...`. This step will install `clang`, `clang++`, and `make`.
+
+### On Windows
+
+Install the current version of Python from the [Microsoft Store package](https://docs.python.org/3/using/windows.html#the-microsoft-store-package).
+
+Install tools and configuration manually:
+   * Install Visual C++ Build Environment: [Visual Studio Build Tools](https://visualstudio.microsoft.com/thank-you-downloading-visual-studio/?sku=BuildTools)
+   (using "Visual C++ build tools" workload) or [Visual Studio Community](https://visualstudio.microsoft.com/thank-you-downloading-visual-studio/?sku=Community)
+   (using the "Desktop development with C++" workload)
+   * Launch cmd, `npm config set msvs_version 2017`
+
+   If the above steps didn't work for you, please visit [Microsoft's Node.js Guidelines for Windows](https://github.com/Microsoft/nodejs-guidelines/blob/master/windows-environment.md#compiling-native-addon-modules) for additional tips.
+
+   To target native ARM64 Node.js on Windows 10 on ARM, add the components "Visual C++ compilers and libraries for ARM64" and "Visual C++ ATL for ARM64".
+
+### Configuring Python Dependency
+
+`node-gyp` requires that you have installed a compatible version of Python, one of: v3.6, v3.7,
+v3.8, or v3.9. If you have multiple Python versions installed, you can identify which Python
+version `node-gyp` should use in one of the following ways:
+
+1. by setting the `--python` command-line option, e.g.:
+
+``` bash
+node-gyp <command> --python /path/to/executable/python
+```
+
+2. If `node-gyp` is called by way of `npm`, *and* you have multiple versions of
+Python installed, then you can set `npm`'s 'python' config key to the appropriate
+value:
+
+``` bash
+npm config set python /path/to/executable/python
+```
+
+3. If the `PYTHON` environment variable is set to the path of a Python executable,
+then that version will be used, if it is a compatible version.
+
+4. If the `NODE_GYP_FORCE_PYTHON` environment variable is set to the path of a
+Python executable, it will be used instead of any of the other configured or
+builtin Python search paths. If it's not a compatible version, no further
+searching will be done.
+
+### Build for Third Party Node.js Runtimes
+
+When building modules for thid party Node.js runtimes like Electron, which have
+different build configurations from the official Node.js distribution, you
+should use `--dist-url` or `--nodedir` flags to specify the headers of the
+runtime to build for.
+
+Also when `--dist-url` or `--nodedir` flags are passed, node-gyp will use the
+`config.gypi` shipped in the headers distribution to generate build
+configurations, which is different from the default mode that would use the
+`process.config` object of the running Node.js instance.
+
+Some old versions of Electron shipped malformed `config.gypi` in their headers
+distributions, and you might need to pass `--force-process-config` to node-gyp
+to work around configuration errors.
+
+## How to Use
+
+To compile your native addon, first go to its root directory:
+
+``` bash
+cd my_node_addon
+```
+
+The next step is to generate the appropriate project build files for the current
+platform. Use `configure` for that:
+
+``` bash
+node-gyp configure
+```
+
+Auto-detection fails for Visual C++ Build Tools 2015, so `--msvs_version=2015`
+needs to be added (not needed when run by npm as configured above):
+``` bash
+node-gyp configure --msvs_version=2015
+```
+
+__Note__: The `configure` step looks for a `binding.gyp` file in the current
+directory to process. See below for instructions on creating a `binding.gyp` file.
+
+Now you will have either a `Makefile` (on Unix platforms) or a `vcxproj` file
+(on Windows) in the `build/` directory. Next, invoke the `build` command:
+
+``` bash
+node-gyp build
+```
+
+Now you have your compiled `.node` bindings file! The compiled bindings end up
+in `build/Debug/` or `build/Release/`, depending on the build mode. At this point,
+you can require the `.node` file with Node.js and run your tests!
+
+__Note:__ To create a _Debug_ build of the bindings file, pass the `--debug` (or
+`-d`) switch when running either the `configure`, `build` or `rebuild` commands.
+
+## The `binding.gyp` file
+
+A `binding.gyp` file describes the configuration to build your module, in a
+JSON-like format. This file gets placed in the root of your package, alongside
+`package.json`.
+
+A barebones `gyp` file appropriate for building a Node.js addon could look like:
+
+```python
+{
+  "targets": [
+    {
+      "target_name": "binding",
+      "sources": [ "src/binding.cc" ]
+    }
+  ]
+}
+```
+
+## Further reading
+
+The **[docs](./docs/)** directory contains additional documentation on specific node-gyp topics that may be useful if you are experiencing problems installing or building addons using node-gyp.
+
+Some additional resources for Node.js native addons and writing `gyp` configuration files:
+
+ * ["Going Native" a nodeschool.io tutorial](http://nodeschool.io/#goingnative)
+ * ["Hello World" node addon example](https://github.com/nodejs/node/tree/master/test/addons/hello-world)
+ * [gyp user documentation](https://gyp.gsrc.io/docs/UserDocumentation.md)
+ * [gyp input format reference](https://gyp.gsrc.io/docs/InputFormatReference.md)
+ * [*"binding.gyp" files out in the wild* wiki page](./docs/binding.gyp-files-in-the-wild.md)
+
+## Commands
+
+`node-gyp` responds to the following commands:
+
+| **Command**   | **Description**
+|:--------------|:---------------------------------------------------------------
+| `help`        | Shows the help dialog
+| `build`       | Invokes `make`/`msbuild.exe` and builds the native addon
+| `clean`       | Removes the `build` directory if it exists
+| `configure`   | Generates project build files for the current platform
+| `rebuild`     | Runs `clean`, `configure` and `build` all in a row
+| `install`     | Installs Node.js header files for the given version
+| `list`        | Lists the currently installed Node.js header versions
+| `remove`      | Removes the Node.js header files for the given version
+
+
+## Command Options
+
+`node-gyp` accepts the following command options:
+
+| **Command**                       | **Description**
+|:----------------------------------|:------------------------------------------
+| `-j n`, `--jobs n`                | Run `make` in parallel. The value `max` will use all available CPU cores
+| `--target=v6.2.1`                 | Node.js version to build for (default is `process.version`)
+| `--silly`, `--loglevel=silly`     | Log all progress to console
+| `--verbose`, `--loglevel=verbose` | Log most progress to console
+| `--silent`, `--loglevel=silent`   | Don't log anything to console
+| `debug`, `--debug`                | Make Debug build (default is `Release`)
+| `--release`, `--no-debug`         | Make Release build
+| `-C $dir`, `--directory=$dir`     | Run command in different directory
+| `--make=$make`                    | Override `make` command (e.g. `gmake`)
+| `--thin=yes`                      | Enable thin static libraries
+| `--arch=$arch`                    | Set target architecture (e.g. ia32)
+| `--tarball=$path`                 | Get headers from a local tarball
+| `--devdir=$path`                  | SDK download directory (default is OS cache directory)
+| `--ensure`                        | Don't reinstall headers if already present
+| `--dist-url=$url`                 | Download header tarball from custom URL
+| `--proxy=$url`                    | Set HTTP(S) proxy for downloading header tarball
+| `--noproxy=$urls`                 | Set urls to ignore proxies when downloading header tarball
+| `--cafile=$cafile`                | Override default CA chain (to download tarball)
+| `--nodedir=$path`                 | Set the path to the node source code
+| `--python=$path`                  | Set path to the Python binary
+| `--msvs_version=$version`         | Set Visual Studio version (Windows only)
+| `--solution=$solution`            | Set Visual Studio Solution version (Windows only)
+| `--force-process-config`          | Force using runtime's `process.config` object to generate `config.gypi` file
+
+## Configuration
+
+### Environment variables
+
+Use the form `npm_config_OPTION_NAME` for any of the command options listed
+above (dashes in option names should be replaced by underscores).
+
+For example, to set `devdir` equal to `/tmp/.gyp`, you would:
+
+Run this on Unix:
+
+```bash
+export npm_config_devdir=/tmp/.gyp
+```
+
+Or this on Windows:
+
+```console
+set npm_config_devdir=c:\temp\.gyp
+```
+
+### `npm` configuration
+
+Use the form `OPTION_NAME` for any of the command options listed above.
+
+For example, to set `devdir` equal to `/tmp/.gyp`, you would run:
+
+```bash
+npm config set [--global] devdir /tmp/.gyp
+```
+
+**Note:** Configuration set via `npm` will only be used when `node-gyp`
+is run via `npm`, not when `node-gyp` is run directly.
+
+## License
+
+`node-gyp` is available under the MIT license. See the [LICENSE
+file](LICENSE) for details.
diff --git a/server/node_modules/node-gyp/addon.gypi b/server/node_modules/node-gyp/addon.gypi
new file mode 100644
index 0000000..9327b0d
--- /dev/null
+++ b/server/node_modules/node-gyp/addon.gypi
@@ -0,0 +1,185 @@
+{
+  'variables' : {
+    'node_engine_include_dir%': 'deps/v8/include',
+    'node_host_binary%': 'node',
+    'node_with_ltcg%': 'true',
+  },
+  'target_defaults': {
+    'type': 'loadable_module',
+    'win_delay_load_hook': 'true',
+    'product_prefix': '',
+
+    'conditions': [
+      [ 'node_engine=="chakracore"', {
+        'variables': {
+          'node_engine_include_dir%': 'deps/chakrashim/include'
+        },
+      }]
+    ],
+
+    'include_dirs': [
+      '<(node_root_dir)/include/node',
+      '<(node_root_dir)/src',
+      '<(node_root_dir)/deps/openssl/config',
+      '<(node_root_dir)/deps/openssl/openssl/include',
+      '<(node_root_dir)/deps/uv/include',
+      '<(node_root_dir)/deps/zlib',
+      '<(node_root_dir)/<(node_engine_include_dir)'
+    ],
+    'defines!': [
+      'BUILDING_UV_SHARED=1',  # Inherited from common.gypi.
+      'BUILDING_V8_SHARED=1',  # Inherited from common.gypi.
+    ],
+    'defines': [
+      'NODE_GYP_MODULE_NAME=>(_target_name)',
+      'USING_UV_SHARED=1',
+      'USING_V8_SHARED=1',
+      # Warn when using deprecated V8 APIs.
+      'V8_DEPRECATION_WARNINGS=1'
+    ],
+
+    'target_conditions': [
+      ['_type=="loadable_module"', {
+        'product_extension': 'node',
+        'defines': [
+          'BUILDING_NODE_EXTENSION'
+        ],
+        'xcode_settings': {
+          'OTHER_LDFLAGS': [
+            '-undefined dynamic_lookup'
+          ],
+        },
+      }],
+
+      ['_type=="static_library"', {
+        # set to `1` to *disable* the -T thin archive 'ld' flag.
+        # older linkers don't support this flag.
+        'standalone_static_library': '<(standalone_static_library)'
+      }],
+
+      ['_type!="executable"', {
+        'conditions': [
+          [ 'OS=="android"', {
+            'cflags!': [ '-fPIE' ],
+          }]
+        ]
+      }],
+
+      ['_win_delay_load_hook=="true"', {
+        # If the addon specifies `'win_delay_load_hook': 'true'` in its
+        # binding.gyp, link a delay-load hook into the DLL. This hook ensures
+        # that the addon will work regardless of whether the node/iojs binary
+        # is named node.exe, iojs.exe, or something else.
+        'conditions': [
+          [ 'OS=="win"', {
+            'defines': [ 'HOST_BINARY=\"<(node_host_binary)<(EXECUTABLE_SUFFIX)\"', ],
+            'sources': [
+              '<(node_gyp_dir)/src/win_delay_load_hook.cc',
+            ],
+            'msvs_settings': {
+              'VCLinkerTool': {
+                'DelayLoadDLLs': [ '<(node_host_binary)<(EXECUTABLE_SUFFIX)' ],
+                # Don't print a linker warning when no imports from either .exe
+                # are used.
+                'AdditionalOptions': [ '/ignore:4199' ],
+              },
+            },
+          }],
+        ],
+      }],
+    ],
+
+    'conditions': [
+      [ 'OS=="mac"', {
+        'defines': [
+          '_DARWIN_USE_64_BIT_INODE=1'
+        ],
+        'xcode_settings': {
+          'DYLIB_INSTALL_NAME_BASE': '@rpath'
+        },
+      }],
+      [ 'OS=="aix"', {
+        'ldflags': [
+          '-Wl,-bimport:<(node_exp_file)'
+        ],
+      }],
+      [ 'OS=="zos"', {
+        'cflags': [
+          '-q64',
+          '-Wc,DLL',
+          '-qlonglong',
+          '-qenum=int',
+          '-qxclang=-fexec-charset=ISO8859-1'
+        ],
+        'defines': [
+          '_ALL_SOURCE=1',
+          'MAP_FAILED=-1',
+          '_UNIX03_SOURCE=1'
+        ],
+        'ldflags': [
+          '-q64',
+          '<(node_exp_file)'
+        ],
+      }],
+      [ 'OS=="win"', {
+        'conditions': [
+          ['node_engine=="chakracore"', {
+            'library_dirs': [ '<(node_root_dir)/$(ConfigurationName)' ],
+            'libraries': [ '<@(node_engine_libs)' ],
+          }],
+          ['node_with_ltcg=="true"', {
+            'msvs_settings': {
+              'VCCLCompilerTool': {
+                'WholeProgramOptimization': 'true' # /GL, whole program optimization, needed for LTCG
+              },
+              'VCLibrarianTool': {
+                'AdditionalOptions': [
+                  '/LTCG:INCREMENTAL', # incremental link-time code generation
+                ]
+              },
+              'VCLinkerTool': {
+                'OptimizeReferences': 2, # /OPT:REF
+                'EnableCOMDATFolding': 2, # /OPT:ICF
+                'LinkIncremental': 1, # disable incremental linking
+                'AdditionalOptions': [
+                  '/LTCG:INCREMENTAL', # incremental link-time code generation
+                ]
+              }
+            }
+          }]
+        ],
+        'libraries': [
+          '-lkernel32.lib',
+          '-luser32.lib',
+          '-lgdi32.lib',
+          '-lwinspool.lib',
+          '-lcomdlg32.lib',
+          '-ladvapi32.lib',
+          '-lshell32.lib',
+          '-lole32.lib',
+          '-loleaut32.lib',
+          '-luuid.lib',
+          '-lodbc32.lib',
+          '-lDelayImp.lib',
+          '-l"<(node_lib_file)"'
+        ],
+        'msvs_disabled_warnings': [
+          # warning C4251: 'node::ObjectWrap::handle_' : class 'v8::Persistent<T>'
+          # needs to have dll-interface to be used by
+          # clients of class 'node::ObjectWrap'
+          4251
+        ],
+      }, {
+        # OS!="win"
+        'defines': [
+          '_LARGEFILE_SOURCE',
+          '_FILE_OFFSET_BITS=64'
+        ],
+      }],
+      [ 'OS in "freebsd openbsd netbsd solaris android" or \
+         (OS=="linux" and target_arch!="ia32")', {
+        'cflags': [ '-fPIC' ],
+      }],
+    ]
+  }
+}
diff --git a/server/node_modules/node-gyp/bin/node-gyp.js b/server/node_modules/node-gyp/bin/node-gyp.js
new file mode 100755
index 0000000..8652ea2
--- /dev/null
+++ b/server/node_modules/node-gyp/bin/node-gyp.js
@@ -0,0 +1,140 @@
+#!/usr/bin/env node
+
+'use strict'
+
+process.title = 'node-gyp'
+
+const envPaths = require('env-paths')
+const gyp = require('../')
+const log = require('npmlog')
+const os = require('os')
+
+/**
+ * Process and execute the selected commands.
+ */
+
+const prog = gyp()
+var completed = false
+prog.parseArgv(process.argv)
+prog.devDir = prog.opts.devdir
+
+var homeDir = os.homedir()
+if (prog.devDir) {
+  prog.devDir = prog.devDir.replace(/^~/, homeDir)
+} else if (homeDir) {
+  prog.devDir = envPaths('node-gyp', { suffix: '' }).cache
+} else {
+  throw new Error(
+    "node-gyp requires that the user's home directory is specified " +
+    'in either of the environmental variables HOME or USERPROFILE. ' +
+    'Overide with: --devdir /path/to/.node-gyp')
+}
+
+if (prog.todo.length === 0) {
+  if (~process.argv.indexOf('-v') || ~process.argv.indexOf('--version')) {
+    console.log('v%s', prog.version)
+  } else {
+    console.log('%s', prog.usage())
+  }
+  process.exit(0)
+}
+
+log.info('it worked if it ends with', 'ok')
+log.verbose('cli', process.argv)
+log.info('using', 'node-gyp@%s', prog.version)
+log.info('using', 'node@%s | %s | %s', process.versions.node, process.platform, process.arch)
+
+/**
+ * Change dir if -C/--directory was passed.
+ */
+
+var dir = prog.opts.directory
+if (dir) {
+  var fs = require('fs')
+  try {
+    var stat = fs.statSync(dir)
+    if (stat.isDirectory()) {
+      log.info('chdir', dir)
+      process.chdir(dir)
+    } else {
+      log.warn('chdir', dir + ' is not a directory')
+    }
+  } catch (e) {
+    if (e.code === 'ENOENT') {
+      log.warn('chdir', dir + ' is not a directory')
+    } else {
+      log.warn('chdir', 'error during chdir() "%s"', e.message)
+    }
+  }
+}
+
+function run () {
+  var command = prog.todo.shift()
+  if (!command) {
+    // done!
+    completed = true
+    log.info('ok')
+    return
+  }
+
+  prog.commands[command.name](command.args, function (err) {
+    if (err) {
+      log.error(command.name + ' error')
+      log.error('stack', err.stack)
+      errorMessage()
+      log.error('not ok')
+      return process.exit(1)
+    }
+    if (command.name === 'list') {
+      var versions = arguments[1]
+      if (versions.length > 0) {
+        versions.forEach(function (version) {
+          console.log(version)
+        })
+      } else {
+        console.log('No node development files installed. Use `node-gyp install` to install a version.')
+      }
+    } else if (arguments.length >= 2) {
+      console.log.apply(console, [].slice.call(arguments, 1))
+    }
+
+    // now run the next command in the queue
+    process.nextTick(run)
+  })
+}
+
+process.on('exit', function (code) {
+  if (!completed && !code) {
+    log.error('Completion callback never invoked!')
+    issueMessage()
+    process.exit(6)
+  }
+})
+
+process.on('uncaughtException', function (err) {
+  log.error('UNCAUGHT EXCEPTION')
+  log.error('stack', err.stack)
+  issueMessage()
+  process.exit(7)
+})
+
+function errorMessage () {
+  // copied from npm's lib/utils/error-handler.js
+  var os = require('os')
+  log.error('System', os.type() + ' ' + os.release())
+  log.error('command', process.argv
+    .map(JSON.stringify).join(' '))
+  log.error('cwd', process.cwd())
+  log.error('node -v', process.version)
+  log.error('node-gyp -v', 'v' + prog.package.version)
+}
+
+function issueMessage () {
+  errorMessage()
+  log.error('', ['Node-gyp failed to build your package.',
+    'Try to update npm and/or node-gyp and if it does not help file an issue with the package author.'
+  ].join('\n'))
+}
+
+// start running the given commands!
+run()
diff --git a/server/node_modules/node-gyp/docs/Common-issues.md b/server/node_modules/node-gyp/docs/Common-issues.md
new file mode 100644
index 0000000..ae05fe3
--- /dev/null
+++ b/server/node_modules/node-gyp/docs/Common-issues.md
@@ -0,0 +1,14 @@
+## Python Issues OSX
+
+Make sure you are using the native Python version in OSX.  If you use a MacPorts of HomeBrew version, you may run into problems.
+
+If you have issues with `execvp`, be sure to check your `$PYTHON` environment variable.  If it is not set to the native version, unset it and try again.
+
+Notes: https://gist.github.com/erichocean/5177582
+
+## npm ERR! `node-gyp rebuild`(Windows)
+* just install the build tools from [here](https://visualstudio.microsoft.com/thank-you-downloading-visual-studio/?sku=BuildTools)
+Please note the version as is required in below command e.g **2017**
+* Launch cmd, run `npm config set msvs_version 2017`
+* close and open new CMD/terminal and all is well :100: 
+
diff --git a/server/node_modules/node-gyp/docs/Error-pre-versions-of-node-cannot-be-installed.md b/server/node_modules/node-gyp/docs/Error-pre-versions-of-node-cannot-be-installed.md
new file mode 100644
index 0000000..c1e1158
--- /dev/null
+++ b/server/node_modules/node-gyp/docs/Error-pre-versions-of-node-cannot-be-installed.md
@@ -0,0 +1,94 @@
+When using `node-gyp` you might see an error like this when attempting to compile/install a node.js native addon:
+
+```
+$ npm install bcrypt
+npm http GET https://registry.npmjs.org/bcrypt/0.7.5
+npm http 304 https://registry.npmjs.org/bcrypt/0.7.5
+npm http GET https://registry.npmjs.org/bindings/1.0.0
+npm http 304 https://registry.npmjs.org/bindings/1.0.0
+
+> bcrypt@0.7.5 install /home/ubuntu/public/song-swap/node_modules/bcrypt
+> node-gyp rebuild
+
+gyp ERR! configure error
+gyp ERR! stack Error: "pre" versions of node cannot be installed, use the --nodedir flag instead
+gyp ERR! stack     at install (/usr/local/lib/node_modules/npm/node_modules/node-gyp/lib/install.js:69:16)
+gyp ERR! stack     at Object.self.commands.(anonymous function) [as install] (/usr/local/lib/node_modules/npm/node_modules/node-gyp/lib/node-gyp.js:56:37)
+gyp ERR! stack     at getNodeDir (/usr/local/lib/node_modules/npm/node_modules/node-gyp/lib/configure.js:219:20)
+gyp ERR! stack     at /usr/local/lib/node_modules/npm/node_modules/node-gyp/lib/configure.js:105:9
+gyp ERR! stack     at ChildProcess.exithandler (child_process.js:630:7)
+gyp ERR! stack     at ChildProcess.EventEmitter.emit (events.js:99:17)
+gyp ERR! stack     at maybeClose (child_process.js:730:16)
+gyp ERR! stack     at Process.ChildProcess._handle.onexit (child_process.js:797:5)
+gyp ERR! System Linux 3.5.0-21-generic
+gyp ERR! command "node" "/usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
+gyp ERR! cwd /home/ubuntu/public/song-swap/node_modules/bcrypt
+gyp ERR! node -v v0.11.2-pre
+gyp ERR! node-gyp -v v0.9.5
+gyp ERR! not ok
+npm ERR! bcrypt@0.7.5 install: `node-gyp rebuild`
+npm ERR! `sh "-c" "node-gyp rebuild"` failed with 1
+npm ERR!
+npm ERR! Failed at the bcrypt@0.7.5 install script.
+npm ERR! This is most likely a problem with the bcrypt package,
+npm ERR! not with npm itself.
+npm ERR! Tell the author that this fails on your system:
+npm ERR!     node-gyp rebuild
+npm ERR! You can get their info via:
+npm ERR!     npm owner ls bcrypt
+npm ERR! There is likely additional logging output above.
+
+npm ERR! System Linux 3.5.0-21-generic
+npm ERR! command "/usr/local/bin/node" "/usr/local/bin/npm" "install" "bcrypt"
+npm ERR! cwd /home/ubuntu/public/song-swap
+npm ERR! node -v v0.11.2-pre
+npm ERR! npm -v 1.2.18
+npm ERR! code ELIFECYCLE
+npm ERR!
+npm ERR! Additional logging details can be found in:
+npm ERR!     /home/ubuntu/public/song-swap/npm-debug.log
+npm ERR! not ok code 0
+```
+
+The main error here is:
+
+```
+Error: "pre" versions of node cannot be installed, use the --nodedir flag instead
+```
+
+This error is caused when you attempt to compile a native addon using a version of node.js with `-pre` at the end of the version number:
+
+``` bash
+$ node -v
+v0.10.4-pre
+```
+
+## How to avoid (the short answer)
+
+To avoid this error completely just use a stable release of node.js. i.e. `v0.10.4`, and __not__ `v0.10.4-pre`.
+
+## How to fix (the long answer)
+
+This error happens because `node-gyp` does not know what header files were used to compile your "pre" version of node, and therefore it needs you to specify the node source code directory path using the `--nodedir` flag.
+
+For example, if I compiled my development ("pre") version of node.js using the source code in `/Users/nrajlich/node`, then I could invoke `node-gyp` like:
+
+``` bash
+$ node-gyp rebuild --nodedir=/Users/nrajlich/node
+```
+
+Or install an native addon through `npm` like:
+
+``` bash
+$ npm install bcrypt --nodedir=/Users/nrajlich/node
+```
+
+### Always use `--nodedir`
+
+__Note:__ This is for advanced users who use `-pre` versions of node more often than tagged releases.
+
+If you're invoking `node-gyp` through `npm`, then you can leverage `npm`'s configuration system and not have to specify the `--nodedir` flag all the time:
+
+``` bash
+$ npm config set nodedir /Users/nrajlich/node
+```
\ No newline at end of file
diff --git a/server/node_modules/node-gyp/docs/Home.md b/server/node_modules/node-gyp/docs/Home.md
new file mode 100644
index 0000000..fe09986
--- /dev/null
+++ b/server/node_modules/node-gyp/docs/Home.md
@@ -0,0 +1,7 @@
+Welcome to the node-gyp wiki!
+
+ * [["binding.gyp" files out in the wild]]
+ * [[Linking to OpenSSL]]
+ * [[Common Issues]]
+ * [[Updating npm's bundled node-gyp]]
+ * [[Error: "pre" versions of node cannot be installed]]
diff --git a/server/node_modules/node-gyp/docs/Linking-to-OpenSSL.md b/server/node_modules/node-gyp/docs/Linking-to-OpenSSL.md
new file mode 100644
index 0000000..ec80929
--- /dev/null
+++ b/server/node_modules/node-gyp/docs/Linking-to-OpenSSL.md
@@ -0,0 +1,86 @@
+A handful of native addons require linking to OpenSSL in one way or another. This introduces a small challenge since node will sometimes bundle OpenSSL statically (the default for node >= v0.8.x), or sometimes dynamically link to the system OpenSSL (default for node <= v0.6.x).
+
+Good native addons should account for both scenarios. It's recommended that you use the `binding.gyp` file provided below as a starting-point for any addon that needs to use OpenSSL:
+
+``` python
+{
+  'variables': {
+    # node v0.6.x doesn't give us its build variables,
+    # but on Unix it was only possible to use the system OpenSSL library,
+    # so default the variable to "true", v0.8.x node and up will overwrite it.
+    'node_shared_openssl%': 'true'
+  },
+  'targets': [
+    {
+      'target_name': 'binding',
+      'sources': [
+        'src/binding.cc'
+      ],
+      'conditions': [
+        ['node_shared_openssl=="false"', {
+          # so when "node_shared_openssl" is "false", then OpenSSL has been
+          # bundled into the node executable. So we need to include the same
+          # header files that were used when building node.
+          'include_dirs': [
+            '<(node_root_dir)/deps/openssl/openssl/include'
+          ],
+          "conditions" : [
+            ["target_arch=='ia32'", {
+              "include_dirs": [ "<(node_root_dir)/deps/openssl/config/piii" ]
+            }],
+            ["target_arch=='x64'", {
+              "include_dirs": [ "<(node_root_dir)/deps/openssl/config/k8" ]
+            }],
+            ["target_arch=='arm'", {
+              "include_dirs": [ "<(node_root_dir)/deps/openssl/config/arm" ]
+            }]
+          ]
+        }]
+      ]
+    }
+  ]
+}
+```
+
+This ensures that when OpenSSL is statically linked into `node` then, the bundled OpenSSL headers are included, but when the system OpenSSL is in use, then only those headers will be used.
+
+## Windows?
+
+As you can see this baseline `binding.gyp` file only accounts for the Unix scenario. Currently on Windows the situation is a little less ideal. On Windows, OpenSSL is _always_ statically compiled into the `node` executable, so ideally it would be possible to use that copy of OpenSSL when building native addons.
+
+Unfortunately it doesn't seem like that is possible at the moment, as there would need to be tweaks made to the generated `node.lib` file to include the openssl glue functions, or a new `openssl.lib` file would need to be created during the node build. I'm not sure which is the easiest/most feasible.
+
+In the meantime, one possible solution is using another copy of OpenSSL, which is what [`node-bcrypt`](https://github.com/ncb000gt/node.bcrypt.js) currently does. Adding something like this to your `binding.gyp` file's `"conditions"` block would enable this:
+
+``` python
+    [ 'OS=="win"', {
+      'conditions': [
+        # "openssl_root" is the directory on Windows of the OpenSSL files.
+        # Check the "target_arch" variable to set good default values for
+        # both 64-bit and 32-bit builds of the module.
+        ['target_arch=="x64"', {
+          'variables': {
+            'openssl_root%': 'C:/OpenSSL-Win64'
+          },
+        }, {
+          'variables': {
+            'openssl_root%': 'C:/OpenSSL-Win32'
+          },
+        }],
+      ],
+      'libraries': [ 
+        '-l<(openssl_root)/lib/libeay32.lib',
+      ],
+      'include_dirs': [
+        '<(openssl_root)/include',
+      ],
+    }]
+```
+
+Now you can direct your users to install OpenSSL on Windows from here (be sure to tell them to install the 64-bit version if they're compiling against a 64-bit version of node): http://slproweb.com/products/Win32OpenSSL.html
+
+Also note that both `node-gyp` and `npm` allow you to overwrite that default `openssl_root` variable on the command line:
+
+``` bash
+$ node-gyp rebuild --openssl-root="C:\Users\Nathan\Desktop\openssl"
+```
\ No newline at end of file
diff --git a/server/node_modules/node-gyp/docs/Updating-npm-bundled-node-gyp.md b/server/node_modules/node-gyp/docs/Updating-npm-bundled-node-gyp.md
new file mode 100644
index 0000000..0777687
--- /dev/null
+++ b/server/node_modules/node-gyp/docs/Updating-npm-bundled-node-gyp.md
@@ -0,0 +1,45 @@
+# Updating the npm-bundled version of node-gyp
+
+[Many issues](https://github.com/nodejs/node-gyp/labels/ERR%21%20node-gyp%20-v%20%3C%3D%20v5.1.0) are opened by users who are
+not running a [current version of node-gyp](https://github.com/nodejs/node-gyp/releases).
+
+`npm` bundles its own, internal, copy of `node-gyp`. This internal copy is independent of any globally installed copy of node-gyp that
+may have been installed via `npm install -g node-gyp`.
+
+Generally, npm's library files are installed inside your global "node_modules", where npm is installed (run `npm prefix` and add `lib/node_modules`, or just `node_modules` for Windows). There are some exceptions to this. Inside this global `node_modules/` there will be an `npm/` directory and inside this you'll find a `node_modules/node-gyp/` directory. So it may look something like `/usr/local/lib/node_modules/npm/node_modules/node-gyp/`. This is the version of node-gyp that ships with npm.
+
+When you install a _new_ version of node-gyp outside of npm, it'll go into your global node_modules, but not under the `npm/node_modules`. So that may look like `/usr/local/lib/node_modules/node-gyp/`. It'll have the `node-gyp` executable linked into your `PATH` so running `node-gyp` will use this version.
+
+The catch is that npm won't use this version unless you tell it to, it'll keep on using the one you have installed. You need to instruct it to by setting the `node_gyp` config variable (which goes into your `~/.npmrc`). You do this by running the `npm config set` command as below. Then npm will use the command in the path you supply whenever it needs to build a native addon.
+
+**Important**: You also need to remember to unset this when you upgrade npm with a newer version of node-gyp, or you have to manually keep your globally installed node-gyp to date. See "Undo" below.
+
+## Linux and macOS
+```
+npm install --global node-gyp@latest
+npm config set node_gyp $(npm prefix -g)/lib/node_modules/node-gyp/bin/node-gyp.js
+```
+
+`sudo` may be required for the first command if you get a permission error.
+
+## Windows
+
+### Windows Command Prompt
+```
+npm install --global node-gyp@latest
+for /f "delims=" %P in ('npm prefix -g') do npm config set node_gyp "%P\node_modules\node-gyp\bin\node-gyp.js"
+```
+
+### Powershell
+```
+npm install --global node-gyp@latest
+npm prefix -g | % {npm config set node_gyp "$_\node_modules\node-gyp\bin\node-gyp.js"}
+```
+
+## Undo
+**Beware** if you don't unset the `node_gyp` config option, npm will continue to use the globally installed version of node-gyp rather than the one it ships with, which may end up being newer.
+
+```
+npm config delete node_gyp
+npm uninstall --global node-gyp
+```
diff --git a/server/node_modules/node-gyp/docs/binding.gyp-files-in-the-wild.md b/server/node_modules/node-gyp/docs/binding.gyp-files-in-the-wild.md
new file mode 100644
index 0000000..c4603dd
--- /dev/null
+++ b/server/node_modules/node-gyp/docs/binding.gyp-files-in-the-wild.md
@@ -0,0 +1,48 @@
+This page contains links to some examples of existing `binding.gyp` files that other node modules are using. Take a look at them for inspiration.
+
+To add to this page, just add the link to the project's `binding.gyp` file below:
+
+ * [ons](https://github.com/XadillaX/aliyun-ons/blob/master/binding.gyp)
+ * [thmclrx](https://github.com/XadillaX/thmclrx/blob/master/binding.gyp)
+ * [libxmljs](https://github.com/polotek/libxmljs/blob/master/binding.gyp)
+ * [node-buffertools](https://github.com/bnoordhuis/node-buffertools/blob/master/binding.gyp)
+ * [node-canvas](https://github.com/LearnBoost/node-canvas/blob/master/binding.gyp)
+ * [node-ffi](https://github.com/rbranson/node-ffi/blob/master/binding.gyp) + [libffi](https://github.com/rbranson/node-ffi/blob/master/deps/libffi/libffi.gyp)
+ * [node-time](https://github.com/TooTallNate/node-time/blob/master/binding.gyp)
+ * [node-sass](https://github.com/sass/node-sass/blob/master/binding.gyp) + [libsass](https://github.com/sass/node-sass/blob/master/src/libsass.gyp)
+ * [node-serialport](https://github.com/voodootikigod/node-serialport/blob/master/binding.gyp)
+ * [node-weak](https://github.com/TooTallNate/node-weak/blob/master/binding.gyp)
+ * [pty.js](https://github.com/chjj/pty.js/blob/master/binding.gyp)
+ * [ref](https://github.com/TooTallNate/ref/blob/master/binding.gyp)
+ * [appjs](https://github.com/milani/appjs/blob/master/binding.gyp)
+ * [nwm](https://github.com/mixu/nwm/blob/master/binding.gyp)
+ * [bcrypt](https://github.com/ncb000gt/node.bcrypt.js/blob/master/binding.gyp)
+ * [nk-mysql](https://github.com/mmod/nodamysql/blob/master/binding.gyp)
+ * [nk-xrm-installer](https://github.com/mmod/nk-xrm-installer/blob/master/binding.gyp) + [includable.gypi](https://github.com/mmod/nk-xrm-installer/blob/master/includable.gypi) + [unpack.py](https://github.com/mmod/nk-xrm-installer/blob/master/unpack.py) + [disburse.py](https://github.com/mmod/nk-xrm-installer/blob/master/disburse.py)   
+   <sub>.py files above provide complete reference for examples of fetching source via http, extracting, and moving files.</sub>
+ * [node-memwatch](https://github.com/lloyd/node-memwatch/blob/master/binding.gyp)
+ * [node-ip2location](https://github.com/bolgovr/node-ip2location/blob/master/binding.gyp)
+ * [node-midi](https://github.com/justinlatimer/node-midi/blob/master/binding.gyp)
+ * [node-sqlite3](https://github.com/developmentseed/node-sqlite3/blob/master/binding.gyp) + [libsqlite3](https://github.com/developmentseed/node-sqlite3/blob/master/deps/sqlite3.gyp)
+ * [node-zipfile](https://github.com/mapbox/node-zipfile/blob/master/binding.gyp)
+ * [node-mapnik](https://github.com/mapnik/node-mapnik/blob/master/binding.gyp)
+ * [node-inotify](https://github.com/c4milo/node-inotify/blob/master/binding.gyp)
+ * [v8-profiler](https://github.com/c4milo/v8-profiler/blob/master/binding.gyp)
+ * [airtunes](https://github.com/radioline/node_airtunes/blob/master/binding.gyp)
+ * [node-fann](https://github.com/c4milo/node-fann/blob/master/binding.gyp)
+ * [node-talib](https://github.com/oransel/node-talib/blob/master/binding.gyp)
+ * [node-leveldown](https://github.com/rvagg/node-leveldown/blob/master/binding.gyp) + [leveldb.gyp](https://github.com/rvagg/node-leveldown/blob/master/deps/leveldb/leveldb.gyp) + [snappy.gyp](https://github.com/rvagg/node-leveldown/blob/master/deps/snappy/snappy.gyp)
+ * [node-expat](https://github.com/astro/node-expat/blob/master/binding.gyp) + [libexpat](https://github.com/astro/node-expat/blob/master/deps/libexpat/libexpat.gyp)
+ * [node-openvg-canvas](https://github.com/luismreis/node-openvg-canvas/blob/master/binding.gyp) + [node-openvg](https://github.com/luismreis/node-openvg/blob/master/binding.gyp)
+ * [node-cryptopp](https://github.com/BatikhSouri/node-cryptopp/blob/master/binding.gyp)
+ * [topcube](https://github.com/creationix/topcube/blob/master/binding.gyp)
+ * [node-osmium](https://github.com/osmcode/node-osmium/blob/master/binding.gyp)
+ * [node-osrm](https://github.com/DennisOSRM/node-osrm)
+ * [node-oracle](https://github.com/joeferner/node-oracle/blob/master/binding.gyp)
+ * [node-process-list](https://github.com/ReklatsMasters/node-process-list/blob/master/binding.gyp)
+ * [node-nanomsg](https://github.com/nickdesaulniers/node-nanomsg/blob/master/binding.gyp)
+ * [Ghostscript4JS](https://github.com/NickNaso/ghostscript4js/blob/master/binding.gyp)
+ * [nodecv](https://github.com/xudafeng/nodecv/blob/master/binding.gyp)
+ * [magick-cli](https://github.com/NickNaso/magick-cli/blob/master/binding.gyp)
+ * [sharp](https://github.com/lovell/sharp/blob/master/binding.gyp)
+ * [krb5](https://github.com/adaltas/node-krb5/blob/master/binding.gyp)
\ No newline at end of file
diff --git a/server/node_modules/node-gyp/gyp/.flake8 b/server/node_modules/node-gyp/gyp/.flake8
new file mode 100644
index 0000000..ea0c768
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/.flake8
@@ -0,0 +1,4 @@
+[flake8]
+max-complexity = 101
+max-line-length = 88
+extend-ignore = E203  # whitespace before ':' to agree with psf/black
diff --git a/server/node_modules/node-gyp/gyp/.github/workflows/Python_tests.yml b/server/node_modules/node-gyp/gyp/.github/workflows/Python_tests.yml
new file mode 100644
index 0000000..92303b6
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/.github/workflows/Python_tests.yml
@@ -0,0 +1,30 @@
+# TODO: Enable os: windows-latest
+# TODO: Enable pytest --doctest-modules
+
+name: Python_tests
+on: [push, pull_request]
+jobs:
+  Python_tests:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      max-parallel: 8
+      matrix:
+        os: [macos-latest, ubuntu-latest] # , windows-latest]
+        python-version: [3.6, 3.7, 3.8, 3.9]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements_dev.txt
+      - name: Lint with flake8
+        run: flake8 . --ignore=E203,W503  --max-complexity=101 --max-line-length=88 --show-source --statistics
+      - name: Test with pytest
+        run: pytest
+      # - name: Run doctests with pytest
+      #   run: pytest --doctest-modules
diff --git a/server/node_modules/node-gyp/gyp/.github/workflows/node-gyp.yml b/server/node_modules/node-gyp/gyp/.github/workflows/node-gyp.yml
new file mode 100644
index 0000000..bd7c85f
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/.github/workflows/node-gyp.yml
@@ -0,0 +1,42 @@
+name: node-gyp integration
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [macos-latest, ubuntu-latest, windows-latest]
+        python: [3.6, 3.9]
+
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Clone gyp-next
+        uses: actions/checkout@v2
+        with:
+          path: gyp-next
+      - name: Clone nodejs/node-gyp
+        uses: actions/checkout@v2
+        with:
+          repository: nodejs/node-gyp
+          path: node-gyp
+      - uses: actions/setup-node@v2
+        with:
+          node-version: 14.x
+      - uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python }}
+      - name: Install dependencies
+        run: |
+          cd node-gyp
+          npm install --no-progress
+      - name: Replace gyp in node-gyp
+        shell: bash
+        run: |
+          rm -rf node-gyp/gyp
+          cp -r gyp-next node-gyp/gyp
+      - name: Run tests
+        run: |
+          cd node-gyp
+          npm test
diff --git a/server/node_modules/node-gyp/gyp/.github/workflows/nodejs-windows.yml b/server/node_modules/node-gyp/gyp/.github/workflows/nodejs-windows.yml
new file mode 100644
index 0000000..fffe96e
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/.github/workflows/nodejs-windows.yml
@@ -0,0 +1,27 @@
+name: Node.js Windows integration
+
+on: [push, pull_request]
+
+jobs:
+  build-windows:
+    runs-on: windows-latest
+    steps:
+      - name: Clone gyp-next
+        uses: actions/checkout@v2
+        with:
+          path: gyp-next
+      - name: Clone nodejs/node
+        uses: actions/checkout@v2
+        with:
+          repository: nodejs/node
+          path: node
+      - name: Install deps
+        run: choco install nasm
+      - name: Replace gyp in Node.js
+        run: |
+          rm -Recurse node/tools/gyp
+          cp -Recurse gyp-next node/tools/gyp
+      - name: Build Node.js
+        run: |
+          cd node
+          ./vcbuild.bat
diff --git a/server/node_modules/node-gyp/gyp/.github/workflows/release-please.yml b/server/node_modules/node-gyp/gyp/.github/workflows/release-please.yml
new file mode 100644
index 0000000..288afdb
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/.github/workflows/release-please.yml
@@ -0,0 +1,16 @@
+on:
+  push:
+    branches:
+      - main
+
+name: release-please
+jobs:
+  release-please:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: GoogleCloudPlatform/release-please-action@v2
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          release-type: python
+          package-name: gyp-next
+          bump-minor-pre-major: Yes
diff --git a/server/node_modules/node-gyp/gyp/AUTHORS b/server/node_modules/node-gyp/gyp/AUTHORS
new file mode 100644
index 0000000..f49a357
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/AUTHORS
@@ -0,0 +1,16 @@
+# Names should be added to this file like so:
+# Name or Organization <email address>
+
+Google Inc. <*@google.com>
+Bloomberg Finance L.P. <*@bloomberg.net>
+IBM Inc. <*@*.ibm.com>
+Yandex LLC <*@yandex-team.ru>
+
+Steven Knight <knight@baldmt.com>
+Ryan Norton <rnorton10@gmail.com>
+David J. Sankel <david@sankelsoftware.com>
+Eric N. Vander Weele <ericvw@gmail.com>
+Tom Freudenberg <th.freudenberg@gmail.com>
+Julien Brianceau <jbriance@cisco.com>
+Refael Ackermann <refack@gmail.com>
+Ujjwal Sharma <ryzokuken@disroot.org>
diff --git a/server/node_modules/node-gyp/gyp/CHANGELOG.md b/server/node_modules/node-gyp/gyp/CHANGELOG.md
new file mode 100644
index 0000000..b7d55ed
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/CHANGELOG.md
@@ -0,0 +1,177 @@
+# Changelog
+
+## [0.10.0](https://www.github.com/nodejs/gyp-next/compare/v0.9.6...v0.10.0) (2021-08-26)
+
+
+### Features
+
+* **msvs:** add support for Visual Studio 2022 ([#124](https://www.github.com/nodejs/gyp-next/issues/124)) ([4bd9215](https://www.github.com/nodejs/gyp-next/commit/4bd9215c44d300f06e916aec1d6327c22b78272d))
+
+### [0.9.6](https://www.github.com/nodejs/gyp-next/compare/v0.9.5...v0.9.6) (2021-08-23)
+
+
+### Bug Fixes
+
+* align flake8 test ([#122](https://www.github.com/nodejs/gyp-next/issues/122)) ([f1faa8d](https://www.github.com/nodejs/gyp-next/commit/f1faa8d3081e1a47e917ff910892f00dff16cf8a))
+* **msvs:** fix paths again in action command arguments ([#121](https://www.github.com/nodejs/gyp-next/issues/121)) ([7159dfb](https://www.github.com/nodejs/gyp-next/commit/7159dfbc5758c9ec717e215f2c36daf482c846a1))
+
+### [0.9.5](https://www.github.com/nodejs/gyp-next/compare/v0.9.4...v0.9.5) (2021-08-18)
+
+
+### Bug Fixes
+
+* add python 3.6 to node-gyp integration test ([3462d4c](https://www.github.com/nodejs/gyp-next/commit/3462d4ce3c31cce747513dc7ca9760c81d57c60e))
+* revert for windows compatibility ([d078e7d](https://www.github.com/nodejs/gyp-next/commit/d078e7d7ae080ddae243188f6415f940376a7368))
+* support msvs_quote_cmd in ninja generator ([#117](https://www.github.com/nodejs/gyp-next/issues/117)) ([46486ac](https://www.github.com/nodejs/gyp-next/commit/46486ac6e9329529d51061e006a5b39631e46729))
+
+### [0.9.4](https://www.github.com/nodejs/gyp-next/compare/v0.9.3...v0.9.4) (2021-08-09)
+
+
+### Bug Fixes
+
+* .S is an extension for asm file on Windows ([#115](https://www.github.com/nodejs/gyp-next/issues/115)) ([d2fad44](https://www.github.com/nodejs/gyp-next/commit/d2fad44ef3a79ca8900f1307060153ded57053fc))
+
+### [0.9.3](https://www.github.com/nodejs/gyp-next/compare/v0.9.2...v0.9.3) (2021-07-07)
+
+
+### Bug Fixes
+
+* build failure with ninja and Python 3 on Windows ([#113](https://www.github.com/nodejs/gyp-next/issues/113)) ([c172d10](https://www.github.com/nodejs/gyp-next/commit/c172d105deff5db4244e583942215918fa80dd3c))
+
+### [0.9.2](https://www.github.com/nodejs/gyp-next/compare/v0.9.1...v0.9.2) (2021-05-21)
+
+
+### Bug Fixes
+
+* add support of utf8 encoding ([#105](https://www.github.com/nodejs/gyp-next/issues/105)) ([4d0f93c](https://www.github.com/nodejs/gyp-next/commit/4d0f93c249286d1f0c0f665f5fe7346119f98cf1))
+
+### [0.9.1](https://www.github.com/nodejs/gyp-next/compare/v0.9.0...v0.9.1) (2021-05-14)
+
+
+### Bug Fixes
+
+* py lint ([3b6a8ee](https://www.github.com/nodejs/gyp-next/commit/3b6a8ee7a66193a8a6867eba9e1d2b70bdf04402))
+
+## [0.9.0](https://www.github.com/nodejs/gyp-next/compare/v0.8.1...v0.9.0) (2021-05-13)
+
+
+### Features
+
+* use LDFLAGS_host for host toolset ([#98](https://www.github.com/nodejs/gyp-next/issues/98)) ([bea5c7b](https://www.github.com/nodejs/gyp-next/commit/bea5c7bd67d6ad32acbdce79767a5481c70675a2))
+
+
+### Bug Fixes
+
+* msvs.py: remove overindentation ([#102](https://www.github.com/nodejs/gyp-next/issues/102)) ([3f83e99](https://www.github.com/nodejs/gyp-next/commit/3f83e99056d004d9579ceb786e06b624ddc36529))
+* update gyp.el to change case to cl-case ([#93](https://www.github.com/nodejs/gyp-next/issues/93)) ([13d5b66](https://www.github.com/nodejs/gyp-next/commit/13d5b66aab35985af9c2fb1174fdc6e1c1407ecc))
+
+### [0.8.1](https://www.github.com/nodejs/gyp-next/compare/v0.8.0...v0.8.1) (2021-02-18)
+
+
+### Bug Fixes
+
+* update shebang lines from python to python3 ([#94](https://www.github.com/nodejs/gyp-next/issues/94)) ([a1b0d41](https://www.github.com/nodejs/gyp-next/commit/a1b0d4171a8049a4ab7a614202063dec332f2df4))
+
+## [0.8.0](https://www.github.com/nodejs/gyp-next/compare/v0.7.0...v0.8.0) (2021-01-15)
+
+
+### ⚠ BREAKING CHANGES
+
+* remove support for Python 2
+
+### Bug Fixes
+
+* revert posix build job ([#86](https://www.github.com/nodejs/gyp-next/issues/86)) ([39dc34f](https://www.github.com/nodejs/gyp-next/commit/39dc34f0799c074624005fb9bbccf6e028607f9d))
+
+
+### gyp
+
+* Remove support for Python 2 ([#88](https://www.github.com/nodejs/gyp-next/issues/88)) ([22e4654](https://www.github.com/nodejs/gyp-next/commit/22e465426fd892403c95534229af819a99c3f8dc))
+
+## [0.7.0](https://www.github.com/nodejs/gyp-next/compare/v0.6.2...v0.7.0) (2020-12-17)
+
+
+### ⚠ BREAKING CHANGES
+
+* **msvs:** On Windows, arguments passed to the "action" commands are no longer transformed to replace slashes with backslashes.
+
+### Features
+
+* **xcode:** --cross-compiling overrides arch-specific settings ([973bae0](https://www.github.com/nodejs/gyp-next/commit/973bae0b7b08be7b680ecae9565fbd04b3e0787d))
+
+
+### Bug Fixes
+
+* **msvs:** do not fix paths in action command arguments ([fc22f83](https://www.github.com/nodejs/gyp-next/commit/fc22f8335e2016da4aae4f4233074bd651d2faea))
+* cmake on python 3 ([fd61f5f](https://www.github.com/nodejs/gyp-next/commit/fd61f5faa5275ec8fc98e3c7868c0dd46f109540))
+* ValueError: invalid mode: 'rU' while trying to load binding.gyp ([d0504e6](https://www.github.com/nodejs/gyp-next/commit/d0504e6700ce48f44957a4d5891b142a60be946f))
+* xcode cmake parsing ([eefe8d1](https://www.github.com/nodejs/gyp-next/commit/eefe8d10e99863bc4ac7e2ed32facd608d400d4b))
+
+### [0.6.2](https://www.github.com/nodejs/gyp-next/compare/v0.6.1...v0.6.2) (2020-10-16)
+
+
+### Bug Fixes
+
+* do not rewrite absolute paths to avoid long paths ([#74](https://www.github.com/nodejs/gyp-next/issues/74)) ([c2ccc1a](https://www.github.com/nodejs/gyp-next/commit/c2ccc1a81f7f94433a94f4d01a2e820db4c4331a))
+* only include MARMASM when toolset is target ([5a2794a](https://www.github.com/nodejs/gyp-next/commit/5a2794aefb58f0c00404ff042b61740bc8b8d5cd))
+
+### [0.6.1](https://github.com/nodejs/gyp-next/compare/v0.6.0...v0.6.1) (2020-10-14)
+
+
+### Bug Fixes
+
+* Correctly rename object files for absolute paths in MSVS generator.
+
+## [0.6.0](https://github.com/nodejs/gyp-next/compare/v0.5.0...v0.6.0) (2020-10-13)
+
+
+### Features
+
+* The Makefile generator will now output shared libraries directly to the product directory on all platforms (previously only macOS).
+
+## [0.5.0](https://github.com/nodejs/gyp-next/compare/v0.4.0...v0.5.0) (2020-09-30)
+
+
+### Features
+
+* Extended compile_commands_json generator to consider more file extensions than just `c` and `cc`. `cpp` and `cxx` are now supported.
+* Source files with duplicate basenames are now supported.
+
+### Removed
+
+* The `--no-duplicate-basename-check` option was removed.
+* The `msvs_enable_marmasm` configuration option was removed in favor of auto-inclusion of the "marmasm" sections for Windows on ARM.
+
+## [0.4.0](https://github.com/nodejs/gyp-next/compare/v0.3.0...v0.4.0) (2020-07-14)
+
+
+### Features
+
+* Added support for passing arbitrary architectures to Xcode builds, enables `arm64` builds.
+
+### Bug Fixes
+
+* Fixed a bug on Solaris where copying archives failed.
+
+## [0.3.0](https://github.com/nodejs/gyp-next/compare/v0.2.1...v0.3.0) (2020-06-06)
+
+
+### Features
+
+* Added support for MSVC cross-compilation. This allows compilation on x64 for a Windows ARM target.
+
+### Bug Fixes
+
+* Fixed XCode CLT version detection on macOS Catalina.
+
+### [0.2.1](https://github.com/nodejs/gyp-next/compare/v0.2.0...v0.2.1) (2020-05-05)
+
+
+### Bug Fixes
+
+* Relicensed to Node.js contributors.
+* Fixed Windows bug introduced in v0.2.0.
+
+## [0.2.0](https://github.com/nodejs/gyp-next/releases/tag/v0.2.0) (2020-04-06)
+
+This is the first release of this project, based on https://chromium.googlesource.com/external/gyp with changes made over the years in Node.js and node-gyp.
diff --git a/server/node_modules/node-gyp/gyp/CODE_OF_CONDUCT.md b/server/node_modules/node-gyp/gyp/CODE_OF_CONDUCT.md
new file mode 100644
index 0000000..d724027
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/CODE_OF_CONDUCT.md
@@ -0,0 +1,4 @@
+# Code of Conduct
+
+* [Node.js Code of Conduct](https://github.com/nodejs/admin/blob/HEAD/CODE_OF_CONDUCT.md)
+* [Node.js Moderation Policy](https://github.com/nodejs/admin/blob/HEAD/Moderation-Policy.md)
diff --git a/server/node_modules/node-gyp/gyp/CONTRIBUTING.md b/server/node_modules/node-gyp/gyp/CONTRIBUTING.md
new file mode 100644
index 0000000..1a0bcde
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/CONTRIBUTING.md
@@ -0,0 +1,32 @@
+# Contributing to gyp-next
+
+## Code of Conduct
+
+This project is bound to the [Node.js Code of Conduct](https://github.com/nodejs/admin/blob/HEAD/CODE_OF_CONDUCT.md).
+
+<a id="developers-certificate-of-origin"></a>
+## Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+* (a) The contribution was created in whole or in part by me and I
+  have the right to submit it under the open source license
+  indicated in the file; or
+
+* (b) The contribution is based upon previous work that, to the best
+  of my knowledge, is covered under an appropriate open source
+  license and I have the right under that license to submit that
+  work with modifications, whether created in whole or in part
+  by me, under the same open source license (unless I am
+  permitted to submit under a different license), as indicated
+  in the file; or
+
+* (c) The contribution was provided directly to me by some other
+  person who certified (a), (b) or (c) and I have not modified
+  it.
+
+* (d) I understand and agree that this project and the contribution
+  are public and that a record of the contribution (including all
+  personal information I submit with it, including my sign-off) is
+  maintained indefinitely and may be redistributed consistent with
+  this project or the open source license(s) involved.
diff --git a/server/node_modules/node-gyp/gyp/LICENSE b/server/node_modules/node-gyp/gyp/LICENSE
new file mode 100644
index 0000000..c6944c5
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/LICENSE
@@ -0,0 +1,28 @@
+Copyright (c) 2020 Node.js contributors. All rights reserved.
+Copyright (c) 2009 Google Inc. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/server/node_modules/node-gyp/gyp/README.md b/server/node_modules/node-gyp/gyp/README.md
new file mode 100644
index 0000000..9ffc2b2
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/README.md
@@ -0,0 +1,7 @@
+GYP can Generate Your Projects.
+===================================
+
+Documents are available at [gyp.gsrc.io](https://gyp.gsrc.io), or you can check out ```md-pages``` branch to read those documents offline.
+
+__gyp-next__ is [released](https://github.com/nodejs/gyp-next/releases) to the [__Python Packaging Index__](https://pypi.org/project/gyp-next) (PyPI) and can be installed with the command:
+* `python3 -m pip install gyp-next`
diff --git a/server/node_modules/node-gyp/gyp/data/win/large-pdb-shim.cc b/server/node_modules/node-gyp/gyp/data/win/large-pdb-shim.cc
new file mode 100644
index 0000000..8bca510
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/data/win/large-pdb-shim.cc
@@ -0,0 +1,12 @@
+// Copyright (c) 2013 Google Inc. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file is used to generate an empty .pdb -- with a 4KB pagesize -- that is
+// then used during the final link for modules that have large PDBs. Otherwise,
+// the linker will generate a pdb with a page size of 1KB, which imposes a limit
+// of 1GB on the .pdb. By generating an initial empty .pdb with the compiler
+// (rather than the linker), this limit is avoided. With this in place PDBs may
+// grow to 2GB.
+//
+// This file is referenced by the msvs_large_pdb mechanism in MSVSUtil.py.
diff --git a/server/node_modules/node-gyp/gyp/gyp b/server/node_modules/node-gyp/gyp/gyp
new file mode 100755
index 0000000..1b8b9bd
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/gyp
@@ -0,0 +1,8 @@
+#!/bin/sh
+# Copyright 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+set -e
+base=$(dirname "$0")
+exec python "${base}/gyp_main.py" "$@"
diff --git a/server/node_modules/node-gyp/gyp/gyp.bat b/server/node_modules/node-gyp/gyp/gyp.bat
new file mode 100755
index 0000000..c0b4ca2
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/gyp.bat
@@ -0,0 +1,5 @@
+@rem Copyright (c) 2009 Google Inc. All rights reserved.
+@rem Use of this source code is governed by a BSD-style license that can be
+@rem found in the LICENSE file.
+
+@python "%~dp0gyp_main.py" %*
diff --git a/server/node_modules/node-gyp/gyp/gyp_main.py b/server/node_modules/node-gyp/gyp/gyp_main.py
new file mode 100755
index 0000000..f23dcdf
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/gyp_main.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2009 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import sys
+import subprocess
+
+
+def IsCygwin():
+    # Function copied from pylib/gyp/common.py
+    try:
+        out = subprocess.Popen(
+            "uname", stdout=subprocess.PIPE, stderr=subprocess.STDOUT
+        )
+        stdout, _ = out.communicate()
+        return "CYGWIN" in stdout.decode("utf-8")
+    except Exception:
+        return False
+
+
+def UnixifyPath(path):
+    try:
+        if not IsCygwin():
+            return path
+        out = subprocess.Popen(
+            ["cygpath", "-u", path], stdout=subprocess.PIPE, stderr=subprocess.STDOUT
+        )
+        stdout, _ = out.communicate()
+        return stdout.decode("utf-8")
+    except Exception:
+        return path
+
+
+# Make sure we're using the version of pylib in this repo, not one installed
+# elsewhere on the system. Also convert to Unix style path on Cygwin systems,
+# else the 'gyp' library will not be found
+path = UnixifyPath(sys.argv[0])
+sys.path.insert(0, os.path.join(os.path.dirname(path), "pylib"))
+import gyp  # noqa: E402
+
+if __name__ == "__main__":
+    sys.exit(gyp.script_main())
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSNew.py b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSNew.py
new file mode 100644
index 0000000..d6b1897
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSNew.py
@@ -0,0 +1,367 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""New implementation of Visual Studio project generation."""
+
+import hashlib
+import os
+import random
+from operator import attrgetter
+
+import gyp.common
+
+
+def cmp(x, y):
+    return (x > y) - (x < y)
+
+
+# Initialize random number generator
+random.seed()
+
+# GUIDs for project types
+ENTRY_TYPE_GUIDS = {
+    "project": "{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}",
+    "folder": "{2150E333-8FDC-42A3-9474-1A3956D46DE8}",
+}
+
+# ------------------------------------------------------------------------------
+# Helper functions
+
+
+def MakeGuid(name, seed="msvs_new"):
+    """Returns a GUID for the specified target name.
+
+  Args:
+    name: Target name.
+    seed: Seed for MD5 hash.
+  Returns:
+    A GUID-line string calculated from the name and seed.
+
+  This generates something which looks like a GUID, but depends only on the
+  name and seed.  This means the same name/seed will always generate the same
+  GUID, so that projects and solutions which refer to each other can explicitly
+  determine the GUID to refer to explicitly.  It also means that the GUID will
+  not change when the project for a target is rebuilt.
+  """
+    # Calculate a MD5 signature for the seed and name.
+    d = hashlib.md5((str(seed) + str(name)).encode("utf-8")).hexdigest().upper()
+    # Convert most of the signature to GUID form (discard the rest)
+    guid = (
+        "{"
+        + d[:8]
+        + "-"
+        + d[8:12]
+        + "-"
+        + d[12:16]
+        + "-"
+        + d[16:20]
+        + "-"
+        + d[20:32]
+        + "}"
+    )
+    return guid
+
+
+# ------------------------------------------------------------------------------
+
+
+class MSVSSolutionEntry:
+    def __cmp__(self, other):
+        # Sort by name then guid (so things are in order on vs2008).
+        return cmp((self.name, self.get_guid()), (other.name, other.get_guid()))
+
+
+class MSVSFolder(MSVSSolutionEntry):
+    """Folder in a Visual Studio project or solution."""
+
+    def __init__(self, path, name=None, entries=None, guid=None, items=None):
+        """Initializes the folder.
+
+    Args:
+      path: Full path to the folder.
+      name: Name of the folder.
+      entries: List of folder entries to nest inside this folder.  May contain
+          Folder or Project objects.  May be None, if the folder is empty.
+      guid: GUID to use for folder, if not None.
+      items: List of solution items to include in the folder project.  May be
+          None, if the folder does not directly contain items.
+    """
+        if name:
+            self.name = name
+        else:
+            # Use last layer.
+            self.name = os.path.basename(path)
+
+        self.path = path
+        self.guid = guid
+
+        # Copy passed lists (or set to empty lists)
+        self.entries = sorted(entries or [], key=attrgetter("path"))
+        self.items = list(items or [])
+
+        self.entry_type_guid = ENTRY_TYPE_GUIDS["folder"]
+
+    def get_guid(self):
+        if self.guid is None:
+            # Use consistent guids for folders (so things don't regenerate).
+            self.guid = MakeGuid(self.path, seed="msvs_folder")
+        return self.guid
+
+
+# ------------------------------------------------------------------------------
+
+
+class MSVSProject(MSVSSolutionEntry):
+    """Visual Studio project."""
+
+    def __init__(
+        self,
+        path,
+        name=None,
+        dependencies=None,
+        guid=None,
+        spec=None,
+        build_file=None,
+        config_platform_overrides=None,
+        fixpath_prefix=None,
+    ):
+        """Initializes the project.
+
+    Args:
+      path: Absolute path to the project file.
+      name: Name of project.  If None, the name will be the same as the base
+          name of the project file.
+      dependencies: List of other Project objects this project is dependent
+          upon, if not None.
+      guid: GUID to use for project, if not None.
+      spec: Dictionary specifying how to build this project.
+      build_file: Filename of the .gyp file that the vcproj file comes from.
+      config_platform_overrides: optional dict of configuration platforms to
+          used in place of the default for this target.
+      fixpath_prefix: the path used to adjust the behavior of _fixpath
+    """
+        self.path = path
+        self.guid = guid
+        self.spec = spec
+        self.build_file = build_file
+        # Use project filename if name not specified
+        self.name = name or os.path.splitext(os.path.basename(path))[0]
+
+        # Copy passed lists (or set to empty lists)
+        self.dependencies = list(dependencies or [])
+
+        self.entry_type_guid = ENTRY_TYPE_GUIDS["project"]
+
+        if config_platform_overrides:
+            self.config_platform_overrides = config_platform_overrides
+        else:
+            self.config_platform_overrides = {}
+        self.fixpath_prefix = fixpath_prefix
+        self.msbuild_toolset = None
+
+    def set_dependencies(self, dependencies):
+        self.dependencies = list(dependencies or [])
+
+    def get_guid(self):
+        if self.guid is None:
+            # Set GUID from path
+            # TODO(rspangler): This is fragile.
+            # 1. We can't just use the project filename sans path, since there could
+            #    be multiple projects with the same base name (for example,
+            #    foo/unittest.vcproj and bar/unittest.vcproj).
+            # 2. The path needs to be relative to $SOURCE_ROOT, so that the project
+            #    GUID is the same whether it's included from base/base.sln or
+            #    foo/bar/baz/baz.sln.
+            # 3. The GUID needs to be the same each time this builder is invoked, so
+            #    that we don't need to rebuild the solution when the project changes.
+            # 4. We should be able to handle pre-built project files by reading the
+            #    GUID from the files.
+            self.guid = MakeGuid(self.name)
+        return self.guid
+
+    def set_msbuild_toolset(self, msbuild_toolset):
+        self.msbuild_toolset = msbuild_toolset
+
+
+# ------------------------------------------------------------------------------
+
+
+class MSVSSolution:
+    """Visual Studio solution."""
+
+    def __init__(
+        self, path, version, entries=None, variants=None, websiteProperties=True
+    ):
+        """Initializes the solution.
+
+    Args:
+      path: Path to solution file.
+      version: Format version to emit.
+      entries: List of entries in solution.  May contain Folder or Project
+          objects.  May be None, if the folder is empty.
+      variants: List of build variant strings.  If none, a default list will
+          be used.
+      websiteProperties: Flag to decide if the website properties section
+          is generated.
+    """
+        self.path = path
+        self.websiteProperties = websiteProperties
+        self.version = version
+
+        # Copy passed lists (or set to empty lists)
+        self.entries = list(entries or [])
+
+        if variants:
+            # Copy passed list
+            self.variants = variants[:]
+        else:
+            # Use default
+            self.variants = ["Debug|Win32", "Release|Win32"]
+        # TODO(rspangler): Need to be able to handle a mapping of solution config
+        # to project config.  Should we be able to handle variants being a dict,
+        # or add a separate variant_map variable?  If it's a dict, we can't
+        # guarantee the order of variants since dict keys aren't ordered.
+
+        # TODO(rspangler): Automatically write to disk for now; should delay until
+        # node-evaluation time.
+        self.Write()
+
+    def Write(self, writer=gyp.common.WriteOnDiff):
+        """Writes the solution file to disk.
+
+    Raises:
+      IndexError: An entry appears multiple times.
+    """
+        # Walk the entry tree and collect all the folders and projects.
+        all_entries = set()
+        entries_to_check = self.entries[:]
+        while entries_to_check:
+            e = entries_to_check.pop(0)
+
+            # If this entry has been visited, nothing to do.
+            if e in all_entries:
+                continue
+
+            all_entries.add(e)
+
+            # If this is a folder, check its entries too.
+            if isinstance(e, MSVSFolder):
+                entries_to_check += e.entries
+
+        all_entries = sorted(all_entries, key=attrgetter("path"))
+
+        # Open file and print header
+        f = writer(self.path)
+        f.write(
+            "Microsoft Visual Studio Solution File, "
+            "Format Version %s\r\n" % self.version.SolutionVersion()
+        )
+        f.write("# %s\r\n" % self.version.Description())
+
+        # Project entries
+        sln_root = os.path.split(self.path)[0]
+        for e in all_entries:
+            relative_path = gyp.common.RelativePath(e.path, sln_root)
+            # msbuild does not accept an empty folder_name.
+            # use '.' in case relative_path is empty.
+            folder_name = relative_path.replace("/", "\\") or "."
+            f.write(
+                'Project("%s") = "%s", "%s", "%s"\r\n'
+                % (
+                    e.entry_type_guid,  # Entry type GUID
+                    e.name,  # Folder name
+                    folder_name,  # Folder name (again)
+                    e.get_guid(),  # Entry GUID
+                )
+            )
+
+            # TODO(rspangler): Need a way to configure this stuff
+            if self.websiteProperties:
+                f.write(
+                    "\tProjectSection(WebsiteProperties) = preProject\r\n"
+                    '\t\tDebug.AspNetCompiler.Debug = "True"\r\n'
+                    '\t\tRelease.AspNetCompiler.Debug = "False"\r\n'
+                    "\tEndProjectSection\r\n"
+                )
+
+            if isinstance(e, MSVSFolder):
+                if e.items:
+                    f.write("\tProjectSection(SolutionItems) = preProject\r\n")
+                    for i in e.items:
+                        f.write(f"\t\t{i} = {i}\r\n")
+                    f.write("\tEndProjectSection\r\n")
+
+            if isinstance(e, MSVSProject):
+                if e.dependencies:
+                    f.write("\tProjectSection(ProjectDependencies) = postProject\r\n")
+                    for d in e.dependencies:
+                        f.write(f"\t\t{d.get_guid()} = {d.get_guid()}\r\n")
+                    f.write("\tEndProjectSection\r\n")
+
+            f.write("EndProject\r\n")
+
+        # Global section
+        f.write("Global\r\n")
+
+        # Configurations (variants)
+        f.write("\tGlobalSection(SolutionConfigurationPlatforms) = preSolution\r\n")
+        for v in self.variants:
+            f.write(f"\t\t{v} = {v}\r\n")
+        f.write("\tEndGlobalSection\r\n")
+
+        # Sort config guids for easier diffing of solution changes.
+        config_guids = []
+        config_guids_overrides = {}
+        for e in all_entries:
+            if isinstance(e, MSVSProject):
+                config_guids.append(e.get_guid())
+                config_guids_overrides[e.get_guid()] = e.config_platform_overrides
+        config_guids.sort()
+
+        f.write("\tGlobalSection(ProjectConfigurationPlatforms) = postSolution\r\n")
+        for g in config_guids:
+            for v in self.variants:
+                nv = config_guids_overrides[g].get(v, v)
+                # Pick which project configuration to build for this solution
+                # configuration.
+                f.write(
+                    "\t\t%s.%s.ActiveCfg = %s\r\n"
+                    % (
+                        g,  # Project GUID
+                        v,  # Solution build configuration
+                        nv,  # Project build config for that solution config
+                    )
+                )
+
+                # Enable project in this solution configuration.
+                f.write(
+                    "\t\t%s.%s.Build.0 = %s\r\n"
+                    % (
+                        g,  # Project GUID
+                        v,  # Solution build configuration
+                        nv,  # Project build config for that solution config
+                    )
+                )
+        f.write("\tEndGlobalSection\r\n")
+
+        # TODO(rspangler): Should be able to configure this stuff too (though I've
+        # never seen this be any different)
+        f.write("\tGlobalSection(SolutionProperties) = preSolution\r\n")
+        f.write("\t\tHideSolutionNode = FALSE\r\n")
+        f.write("\tEndGlobalSection\r\n")
+
+        # Folder mappings
+        # Omit this section if there are no folders
+        if any([e.entries for e in all_entries if isinstance(e, MSVSFolder)]):
+            f.write("\tGlobalSection(NestedProjects) = preSolution\r\n")
+            for e in all_entries:
+                if not isinstance(e, MSVSFolder):
+                    continue  # Does not apply to projects, only folders
+                for subentry in e.entries:
+                    f.write(f"\t\t{subentry.get_guid()} = {e.get_guid()}\r\n")
+            f.write("\tEndGlobalSection\r\n")
+
+        f.write("EndGlobal\r\n")
+
+        f.close()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSProject.py b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSProject.py
new file mode 100644
index 0000000..f0cfabe
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSProject.py
@@ -0,0 +1,206 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Visual Studio project reader/writer."""
+
+import gyp.easy_xml as easy_xml
+
+# ------------------------------------------------------------------------------
+
+
+class Tool:
+    """Visual Studio tool."""
+
+    def __init__(self, name, attrs=None):
+        """Initializes the tool.
+
+    Args:
+      name: Tool name.
+      attrs: Dict of tool attributes; may be None.
+    """
+        self._attrs = attrs or {}
+        self._attrs["Name"] = name
+
+    def _GetSpecification(self):
+        """Creates an element for the tool.
+
+    Returns:
+      A new xml.dom.Element for the tool.
+    """
+        return ["Tool", self._attrs]
+
+
+class Filter:
+    """Visual Studio filter - that is, a virtual folder."""
+
+    def __init__(self, name, contents=None):
+        """Initializes the folder.
+
+    Args:
+      name: Filter (folder) name.
+      contents: List of filenames and/or Filter objects contained.
+    """
+        self.name = name
+        self.contents = list(contents or [])
+
+
+# ------------------------------------------------------------------------------
+
+
+class Writer:
+    """Visual Studio XML project writer."""
+
+    def __init__(self, project_path, version, name, guid=None, platforms=None):
+        """Initializes the project.
+
+    Args:
+      project_path: Path to the project file.
+      version: Format version to emit.
+      name: Name of the project.
+      guid: GUID to use for project, if not None.
+      platforms: Array of string, the supported platforms.  If null, ['Win32']
+    """
+        self.project_path = project_path
+        self.version = version
+        self.name = name
+        self.guid = guid
+
+        # Default to Win32 for platforms.
+        if not platforms:
+            platforms = ["Win32"]
+
+        # Initialize the specifications of the various sections.
+        self.platform_section = ["Platforms"]
+        for platform in platforms:
+            self.platform_section.append(["Platform", {"Name": platform}])
+        self.tool_files_section = ["ToolFiles"]
+        self.configurations_section = ["Configurations"]
+        self.files_section = ["Files"]
+
+        # Keep a dict keyed on filename to speed up access.
+        self.files_dict = dict()
+
+    def AddToolFile(self, path):
+        """Adds a tool file to the project.
+
+    Args:
+      path: Relative path from project to tool file.
+    """
+        self.tool_files_section.append(["ToolFile", {"RelativePath": path}])
+
+    def _GetSpecForConfiguration(self, config_type, config_name, attrs, tools):
+        """Returns the specification for a configuration.
+
+    Args:
+      config_type: Type of configuration node.
+      config_name: Configuration name.
+      attrs: Dict of configuration attributes; may be None.
+      tools: List of tools (strings or Tool objects); may be None.
+    Returns:
+    """
+        # Handle defaults
+        if not attrs:
+            attrs = {}
+        if not tools:
+            tools = []
+
+        # Add configuration node and its attributes
+        node_attrs = attrs.copy()
+        node_attrs["Name"] = config_name
+        specification = [config_type, node_attrs]
+
+        # Add tool nodes and their attributes
+        if tools:
+            for t in tools:
+                if isinstance(t, Tool):
+                    specification.append(t._GetSpecification())
+                else:
+                    specification.append(Tool(t)._GetSpecification())
+        return specification
+
+    def AddConfig(self, name, attrs=None, tools=None):
+        """Adds a configuration to the project.
+
+    Args:
+      name: Configuration name.
+      attrs: Dict of configuration attributes; may be None.
+      tools: List of tools (strings or Tool objects); may be None.
+    """
+        spec = self._GetSpecForConfiguration("Configuration", name, attrs, tools)
+        self.configurations_section.append(spec)
+
+    def _AddFilesToNode(self, parent, files):
+        """Adds files and/or filters to the parent node.
+
+    Args:
+      parent: Destination node
+      files: A list of Filter objects and/or relative paths to files.
+
+    Will call itself recursively, if the files list contains Filter objects.
+    """
+        for f in files:
+            if isinstance(f, Filter):
+                node = ["Filter", {"Name": f.name}]
+                self._AddFilesToNode(node, f.contents)
+            else:
+                node = ["File", {"RelativePath": f}]
+                self.files_dict[f] = node
+            parent.append(node)
+
+    def AddFiles(self, files):
+        """Adds files to the project.
+
+    Args:
+      files: A list of Filter objects and/or relative paths to files.
+
+    This makes a copy of the file/filter tree at the time of this call.  If you
+    later add files to a Filter object which was passed into a previous call
+    to AddFiles(), it will not be reflected in this project.
+    """
+        self._AddFilesToNode(self.files_section, files)
+        # TODO(rspangler) This also doesn't handle adding files to an existing
+        # filter.  That is, it doesn't merge the trees.
+
+    def AddFileConfig(self, path, config, attrs=None, tools=None):
+        """Adds a configuration to a file.
+
+    Args:
+      path: Relative path to the file.
+      config: Name of configuration to add.
+      attrs: Dict of configuration attributes; may be None.
+      tools: List of tools (strings or Tool objects); may be None.
+
+    Raises:
+      ValueError: Relative path does not match any file added via AddFiles().
+    """
+        # Find the file node with the right relative path
+        parent = self.files_dict.get(path)
+        if not parent:
+            raise ValueError('AddFileConfig: file "%s" not in project.' % path)
+
+        # Add the config to the file node
+        spec = self._GetSpecForConfiguration("FileConfiguration", config, attrs, tools)
+        parent.append(spec)
+
+    def WriteIfChanged(self):
+        """Writes the project file."""
+        # First create XML content definition
+        content = [
+            "VisualStudioProject",
+            {
+                "ProjectType": "Visual C++",
+                "Version": self.version.ProjectVersion(),
+                "Name": self.name,
+                "ProjectGUID": self.guid,
+                "RootNamespace": self.name,
+                "Keyword": "Win32Proj",
+            },
+            self.platform_section,
+            self.tool_files_section,
+            self.configurations_section,
+            ["References"],  # empty section
+            self.files_section,
+            ["Globals"],  # empty section
+        ]
+        easy_xml.WriteXmlIfChanged(content, self.project_path, encoding="Windows-1252")
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSSettings.py b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSSettings.py
new file mode 100644
index 0000000..e89a971
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSSettings.py
@@ -0,0 +1,1270 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+r"""Code to validate and convert settings of the Microsoft build tools.
+
+This file contains code to validate and convert settings of the Microsoft
+build tools.  The function ConvertToMSBuildSettings(), ValidateMSVSSettings(),
+and ValidateMSBuildSettings() are the entry points.
+
+This file was created by comparing the projects created by Visual Studio 2008
+and Visual Studio 2010 for all available settings through the user interface.
+The MSBuild schemas were also considered.  They are typically found in the
+MSBuild install directory, e.g. c:\Program Files (x86)\MSBuild
+"""
+
+import re
+import sys
+
+# Dictionaries of settings validators. The key is the tool name, the value is
+# a dictionary mapping setting names to validation functions.
+_msvs_validators = {}
+_msbuild_validators = {}
+
+
+# A dictionary of settings converters. The key is the tool name, the value is
+# a dictionary mapping setting names to conversion functions.
+_msvs_to_msbuild_converters = {}
+
+
+# Tool name mapping from MSVS to MSBuild.
+_msbuild_name_of_tool = {}
+
+
+class _Tool:
+    """Represents a tool used by MSVS or MSBuild.
+
+  Attributes:
+      msvs_name: The name of the tool in MSVS.
+      msbuild_name: The name of the tool in MSBuild.
+  """
+
+    def __init__(self, msvs_name, msbuild_name):
+        self.msvs_name = msvs_name
+        self.msbuild_name = msbuild_name
+
+
+def _AddTool(tool):
+    """Adds a tool to the four dictionaries used to process settings.
+
+  This only defines the tool.  Each setting also needs to be added.
+
+  Args:
+    tool: The _Tool object to be added.
+  """
+    _msvs_validators[tool.msvs_name] = {}
+    _msbuild_validators[tool.msbuild_name] = {}
+    _msvs_to_msbuild_converters[tool.msvs_name] = {}
+    _msbuild_name_of_tool[tool.msvs_name] = tool.msbuild_name
+
+
+def _GetMSBuildToolSettings(msbuild_settings, tool):
+    """Returns an MSBuild tool dictionary.  Creates it if needed."""
+    return msbuild_settings.setdefault(tool.msbuild_name, {})
+
+
+class _Type:
+    """Type of settings (Base class)."""
+
+    def ValidateMSVS(self, value):
+        """Verifies that the value is legal for MSVS.
+
+    Args:
+      value: the value to check for this type.
+
+    Raises:
+      ValueError if value is not valid for MSVS.
+    """
+
+    def ValidateMSBuild(self, value):
+        """Verifies that the value is legal for MSBuild.
+
+    Args:
+      value: the value to check for this type.
+
+    Raises:
+      ValueError if value is not valid for MSBuild.
+    """
+
+    def ConvertToMSBuild(self, value):
+        """Returns the MSBuild equivalent of the MSVS value given.
+
+    Args:
+      value: the MSVS value to convert.
+
+    Returns:
+      the MSBuild equivalent.
+
+    Raises:
+      ValueError if value is not valid.
+    """
+        return value
+
+
+class _String(_Type):
+    """A setting that's just a string."""
+
+    def ValidateMSVS(self, value):
+        if not isinstance(value, str):
+            raise ValueError("expected string; got %r" % value)
+
+    def ValidateMSBuild(self, value):
+        if not isinstance(value, str):
+            raise ValueError("expected string; got %r" % value)
+
+    def ConvertToMSBuild(self, value):
+        # Convert the macros
+        return ConvertVCMacrosToMSBuild(value)
+
+
+class _StringList(_Type):
+    """A settings that's a list of strings."""
+
+    def ValidateMSVS(self, value):
+        if not isinstance(value, (list, str)):
+            raise ValueError("expected string list; got %r" % value)
+
+    def ValidateMSBuild(self, value):
+        if not isinstance(value, (list, str)):
+            raise ValueError("expected string list; got %r" % value)
+
+    def ConvertToMSBuild(self, value):
+        # Convert the macros
+        if isinstance(value, list):
+            return [ConvertVCMacrosToMSBuild(i) for i in value]
+        else:
+            return ConvertVCMacrosToMSBuild(value)
+
+
+class _Boolean(_Type):
+    """Boolean settings, can have the values 'false' or 'true'."""
+
+    def _Validate(self, value):
+        if value != "true" and value != "false":
+            raise ValueError("expected bool; got %r" % value)
+
+    def ValidateMSVS(self, value):
+        self._Validate(value)
+
+    def ValidateMSBuild(self, value):
+        self._Validate(value)
+
+    def ConvertToMSBuild(self, value):
+        self._Validate(value)
+        return value
+
+
+class _Integer(_Type):
+    """Integer settings."""
+
+    def __init__(self, msbuild_base=10):
+        _Type.__init__(self)
+        self._msbuild_base = msbuild_base
+
+    def ValidateMSVS(self, value):
+        # Try to convert, this will raise ValueError if invalid.
+        self.ConvertToMSBuild(value)
+
+    def ValidateMSBuild(self, value):
+        # Try to convert, this will raise ValueError if invalid.
+        int(value, self._msbuild_base)
+
+    def ConvertToMSBuild(self, value):
+        msbuild_format = (self._msbuild_base == 10) and "%d" or "0x%04x"
+        return msbuild_format % int(value)
+
+
+class _Enumeration(_Type):
+    """Type of settings that is an enumeration.
+
+  In MSVS, the values are indexes like '0', '1', and '2'.
+  MSBuild uses text labels that are more representative, like 'Win32'.
+
+  Constructor args:
+    label_list: an array of MSBuild labels that correspond to the MSVS index.
+        In the rare cases where MSVS has skipped an index value, None is
+        used in the array to indicate the unused spot.
+    new: an array of labels that are new to MSBuild.
+  """
+
+    def __init__(self, label_list, new=None):
+        _Type.__init__(self)
+        self._label_list = label_list
+        self._msbuild_values = {value for value in label_list if value is not None}
+        if new is not None:
+            self._msbuild_values.update(new)
+
+    def ValidateMSVS(self, value):
+        # Try to convert.  It will raise an exception if not valid.
+        self.ConvertToMSBuild(value)
+
+    def ValidateMSBuild(self, value):
+        if value not in self._msbuild_values:
+            raise ValueError("unrecognized enumerated value %s" % value)
+
+    def ConvertToMSBuild(self, value):
+        index = int(value)
+        if index < 0 or index >= len(self._label_list):
+            raise ValueError(
+                "index value (%d) not in expected range [0, %d)"
+                % (index, len(self._label_list))
+            )
+        label = self._label_list[index]
+        if label is None:
+            raise ValueError("converted value for %s not specified." % value)
+        return label
+
+
+# Instantiate the various generic types.
+_boolean = _Boolean()
+_integer = _Integer()
+# For now, we don't do any special validation on these types:
+_string = _String()
+_file_name = _String()
+_folder_name = _String()
+_file_list = _StringList()
+_folder_list = _StringList()
+_string_list = _StringList()
+# Some boolean settings went from numerical values to boolean.  The
+# mapping is 0: default, 1: false, 2: true.
+_newly_boolean = _Enumeration(["", "false", "true"])
+
+
+def _Same(tool, name, setting_type):
+    """Defines a setting that has the same name in MSVS and MSBuild.
+
+  Args:
+    tool: a dictionary that gives the names of the tool for MSVS and MSBuild.
+    name: the name of the setting.
+    setting_type: the type of this setting.
+  """
+    _Renamed(tool, name, name, setting_type)
+
+
+def _Renamed(tool, msvs_name, msbuild_name, setting_type):
+    """Defines a setting for which the name has changed.
+
+  Args:
+    tool: a dictionary that gives the names of the tool for MSVS and MSBuild.
+    msvs_name: the name of the MSVS setting.
+    msbuild_name: the name of the MSBuild setting.
+    setting_type: the type of this setting.
+  """
+
+    def _Translate(value, msbuild_settings):
+        msbuild_tool_settings = _GetMSBuildToolSettings(msbuild_settings, tool)
+        msbuild_tool_settings[msbuild_name] = setting_type.ConvertToMSBuild(value)
+
+    _msvs_validators[tool.msvs_name][msvs_name] = setting_type.ValidateMSVS
+    _msbuild_validators[tool.msbuild_name][msbuild_name] = setting_type.ValidateMSBuild
+    _msvs_to_msbuild_converters[tool.msvs_name][msvs_name] = _Translate
+
+
+def _Moved(tool, settings_name, msbuild_tool_name, setting_type):
+    _MovedAndRenamed(
+        tool, settings_name, msbuild_tool_name, settings_name, setting_type
+    )
+
+
+def _MovedAndRenamed(
+    tool, msvs_settings_name, msbuild_tool_name, msbuild_settings_name, setting_type
+):
+    """Defines a setting that may have moved to a new section.
+
+  Args:
+    tool: a dictionary that gives the names of the tool for MSVS and MSBuild.
+    msvs_settings_name: the MSVS name of the setting.
+    msbuild_tool_name: the name of the MSBuild tool to place the setting under.
+    msbuild_settings_name: the MSBuild name of the setting.
+    setting_type: the type of this setting.
+  """
+
+    def _Translate(value, msbuild_settings):
+        tool_settings = msbuild_settings.setdefault(msbuild_tool_name, {})
+        tool_settings[msbuild_settings_name] = setting_type.ConvertToMSBuild(value)
+
+    _msvs_validators[tool.msvs_name][msvs_settings_name] = setting_type.ValidateMSVS
+    validator = setting_type.ValidateMSBuild
+    _msbuild_validators[msbuild_tool_name][msbuild_settings_name] = validator
+    _msvs_to_msbuild_converters[tool.msvs_name][msvs_settings_name] = _Translate
+
+
+def _MSVSOnly(tool, name, setting_type):
+    """Defines a setting that is only found in MSVS.
+
+  Args:
+    tool: a dictionary that gives the names of the tool for MSVS and MSBuild.
+    name: the name of the setting.
+    setting_type: the type of this setting.
+  """
+
+    def _Translate(unused_value, unused_msbuild_settings):
+        # Since this is for MSVS only settings, no translation will happen.
+        pass
+
+    _msvs_validators[tool.msvs_name][name] = setting_type.ValidateMSVS
+    _msvs_to_msbuild_converters[tool.msvs_name][name] = _Translate
+
+
+def _MSBuildOnly(tool, name, setting_type):
+    """Defines a setting that is only found in MSBuild.
+
+  Args:
+    tool: a dictionary that gives the names of the tool for MSVS and MSBuild.
+    name: the name of the setting.
+    setting_type: the type of this setting.
+  """
+
+    def _Translate(value, msbuild_settings):
+        # Let msbuild-only properties get translated as-is from msvs_settings.
+        tool_settings = msbuild_settings.setdefault(tool.msbuild_name, {})
+        tool_settings[name] = value
+
+    _msbuild_validators[tool.msbuild_name][name] = setting_type.ValidateMSBuild
+    _msvs_to_msbuild_converters[tool.msvs_name][name] = _Translate
+
+
+def _ConvertedToAdditionalOption(tool, msvs_name, flag):
+    """Defines a setting that's handled via a command line option in MSBuild.
+
+  Args:
+    tool: a dictionary that gives the names of the tool for MSVS and MSBuild.
+    msvs_name: the name of the MSVS setting that if 'true' becomes a flag
+    flag: the flag to insert at the end of the AdditionalOptions
+  """
+
+    def _Translate(value, msbuild_settings):
+        if value == "true":
+            tool_settings = _GetMSBuildToolSettings(msbuild_settings, tool)
+            if "AdditionalOptions" in tool_settings:
+                new_flags = "{} {}".format(tool_settings["AdditionalOptions"], flag)
+            else:
+                new_flags = flag
+            tool_settings["AdditionalOptions"] = new_flags
+
+    _msvs_validators[tool.msvs_name][msvs_name] = _boolean.ValidateMSVS
+    _msvs_to_msbuild_converters[tool.msvs_name][msvs_name] = _Translate
+
+
+def _CustomGeneratePreprocessedFile(tool, msvs_name):
+    def _Translate(value, msbuild_settings):
+        tool_settings = _GetMSBuildToolSettings(msbuild_settings, tool)
+        if value == "0":
+            tool_settings["PreprocessToFile"] = "false"
+            tool_settings["PreprocessSuppressLineNumbers"] = "false"
+        elif value == "1":  # /P
+            tool_settings["PreprocessToFile"] = "true"
+            tool_settings["PreprocessSuppressLineNumbers"] = "false"
+        elif value == "2":  # /EP /P
+            tool_settings["PreprocessToFile"] = "true"
+            tool_settings["PreprocessSuppressLineNumbers"] = "true"
+        else:
+            raise ValueError("value must be one of [0, 1, 2]; got %s" % value)
+
+    # Create a bogus validator that looks for '0', '1', or '2'
+    msvs_validator = _Enumeration(["a", "b", "c"]).ValidateMSVS
+    _msvs_validators[tool.msvs_name][msvs_name] = msvs_validator
+    msbuild_validator = _boolean.ValidateMSBuild
+    msbuild_tool_validators = _msbuild_validators[tool.msbuild_name]
+    msbuild_tool_validators["PreprocessToFile"] = msbuild_validator
+    msbuild_tool_validators["PreprocessSuppressLineNumbers"] = msbuild_validator
+    _msvs_to_msbuild_converters[tool.msvs_name][msvs_name] = _Translate
+
+
+fix_vc_macro_slashes_regex_list = ("IntDir", "OutDir")
+fix_vc_macro_slashes_regex = re.compile(
+    r"(\$$(?:%s)$)(?:[\\/]+)" % "|".join(fix_vc_macro_slashes_regex_list)
+)
+
+# Regular expression to detect keys that were generated by exclusion lists
+_EXCLUDED_SUFFIX_RE = re.compile("^(.*)_excluded$")
+
+
+def _ValidateExclusionSetting(setting, settings, error_msg, stderr=sys.stderr):
+    """Verify that 'setting' is valid if it is generated from an exclusion list.
+
+  If the setting appears to be generated from an exclusion list, the root name
+  is checked.
+
+  Args:
+      setting:   A string that is the setting name to validate
+      settings:  A dictionary where the keys are valid settings
+      error_msg: The message to emit in the event of error
+      stderr:    The stream receiving the error messages.
+  """
+    # This may be unrecognized because it's an exclusion list. If the
+    # setting name has the _excluded suffix, then check the root name.
+    unrecognized = True
+    m = re.match(_EXCLUDED_SUFFIX_RE, setting)
+    if m:
+        root_setting = m.group(1)
+        unrecognized = root_setting not in settings
+
+    if unrecognized:
+        # We don't know this setting. Give a warning.
+        print(error_msg, file=stderr)
+
+
+def FixVCMacroSlashes(s):
+    """Replace macros which have excessive following slashes.
+
+  These macros are known to have a built-in trailing slash. Furthermore, many
+  scripts hiccup on processing paths with extra slashes in the middle.
+
+  This list is probably not exhaustive.  Add as needed.
+  """
+    if "$" in s:
+        s = fix_vc_macro_slashes_regex.sub(r"\1", s)
+    return s
+
+
+def ConvertVCMacrosToMSBuild(s):
+    """Convert the MSVS macros found in the string to the MSBuild equivalent.
+
+  This list is probably not exhaustive.  Add as needed.
+  """
+    if "$" in s:
+        replace_map = {
+            "$(ConfigurationName)": "$(Configuration)",
+            "$(InputDir)": "%(RelativeDir)",
+            "$(InputExt)": "%(Extension)",
+            "$(InputFileName)": "%(Filename)%(Extension)",
+            "$(InputName)": "%(Filename)",
+            "$(InputPath)": "%(Identity)",
+            "$(ParentName)": "$(ProjectFileName)",
+            "$(PlatformName)": "$(Platform)",
+            "$(SafeInputName)": "%(Filename)",
+        }
+        for old, new in replace_map.items():
+            s = s.replace(old, new)
+        s = FixVCMacroSlashes(s)
+    return s
+
+
+def ConvertToMSBuildSettings(msvs_settings, stderr=sys.stderr):
+    """Converts MSVS settings (VS2008 and earlier) to MSBuild settings (VS2010+).
+
+  Args:
+      msvs_settings: A dictionary.  The key is the tool name.  The values are
+          themselves dictionaries of settings and their values.
+      stderr: The stream receiving the error messages.
+
+  Returns:
+      A dictionary of MSBuild settings.  The key is either the MSBuild tool name
+      or the empty string (for the global settings).  The values are themselves
+      dictionaries of settings and their values.
+  """
+    msbuild_settings = {}
+    for msvs_tool_name, msvs_tool_settings in msvs_settings.items():
+        if msvs_tool_name in _msvs_to_msbuild_converters:
+            msvs_tool = _msvs_to_msbuild_converters[msvs_tool_name]
+            for msvs_setting, msvs_value in msvs_tool_settings.items():
+                if msvs_setting in msvs_tool:
+                    # Invoke the translation function.
+                    try:
+                        msvs_tool[msvs_setting](msvs_value, msbuild_settings)
+                    except ValueError as e:
+                        print(
+                            "Warning: while converting %s/%s to MSBuild, "
+                            "%s" % (msvs_tool_name, msvs_setting, e),
+                            file=stderr,
+                        )
+                else:
+                    _ValidateExclusionSetting(
+                        msvs_setting,
+                        msvs_tool,
+                        (
+                            "Warning: unrecognized setting %s/%s "
+                            "while converting to MSBuild."
+                            % (msvs_tool_name, msvs_setting)
+                        ),
+                        stderr,
+                    )
+        else:
+            print(
+                "Warning: unrecognized tool %s while converting to "
+                "MSBuild." % msvs_tool_name,
+                file=stderr,
+            )
+    return msbuild_settings
+
+
+def ValidateMSVSSettings(settings, stderr=sys.stderr):
+    """Validates that the names of the settings are valid for MSVS.
+
+  Args:
+      settings: A dictionary.  The key is the tool name.  The values are
+          themselves dictionaries of settings and their values.
+      stderr: The stream receiving the error messages.
+  """
+    _ValidateSettings(_msvs_validators, settings, stderr)
+
+
+def ValidateMSBuildSettings(settings, stderr=sys.stderr):
+    """Validates that the names of the settings are valid for MSBuild.
+
+  Args:
+      settings: A dictionary.  The key is the tool name.  The values are
+          themselves dictionaries of settings and their values.
+      stderr: The stream receiving the error messages.
+  """
+    _ValidateSettings(_msbuild_validators, settings, stderr)
+
+
+def _ValidateSettings(validators, settings, stderr):
+    """Validates that the settings are valid for MSBuild or MSVS.
+
+  We currently only validate the names of the settings, not their values.
+
+  Args:
+      validators: A dictionary of tools and their validators.
+      settings: A dictionary.  The key is the tool name.  The values are
+          themselves dictionaries of settings and their values.
+      stderr: The stream receiving the error messages.
+  """
+    for tool_name in settings:
+        if tool_name in validators:
+            tool_validators = validators[tool_name]
+            for setting, value in settings[tool_name].items():
+                if setting in tool_validators:
+                    try:
+                        tool_validators[setting](value)
+                    except ValueError as e:
+                        print(
+                            f"Warning: for {tool_name}/{setting}, {e}",
+                            file=stderr,
+                        )
+                else:
+                    _ValidateExclusionSetting(
+                        setting,
+                        tool_validators,
+                        (f"Warning: unrecognized setting {tool_name}/{setting}"),
+                        stderr,
+                    )
+
+        else:
+            print("Warning: unrecognized tool %s" % (tool_name), file=stderr)
+
+
+# MSVS and MBuild names of the tools.
+_compile = _Tool("VCCLCompilerTool", "ClCompile")
+_link = _Tool("VCLinkerTool", "Link")
+_midl = _Tool("VCMIDLTool", "Midl")
+_rc = _Tool("VCResourceCompilerTool", "ResourceCompile")
+_lib = _Tool("VCLibrarianTool", "Lib")
+_manifest = _Tool("VCManifestTool", "Manifest")
+_masm = _Tool("MASM", "MASM")
+_armasm = _Tool("ARMASM", "ARMASM")
+
+
+_AddTool(_compile)
+_AddTool(_link)
+_AddTool(_midl)
+_AddTool(_rc)
+_AddTool(_lib)
+_AddTool(_manifest)
+_AddTool(_masm)
+_AddTool(_armasm)
+# Add sections only found in the MSBuild settings.
+_msbuild_validators[""] = {}
+_msbuild_validators["ProjectReference"] = {}
+_msbuild_validators["ManifestResourceCompile"] = {}
+
+# Descriptions of the compiler options, i.e. VCCLCompilerTool in MSVS and
+# ClCompile in MSBuild.
+# See "c:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\1033\cl.xml" for
+# the schema of the MSBuild ClCompile settings.
+
+# Options that have the same name in MSVS and MSBuild
+_Same(_compile, "AdditionalIncludeDirectories", _folder_list)  # /I
+_Same(_compile, "AdditionalOptions", _string_list)
+_Same(_compile, "AdditionalUsingDirectories", _folder_list)  # /AI
+_Same(_compile, "AssemblerListingLocation", _file_name)  # /Fa
+_Same(_compile, "BrowseInformationFile", _file_name)
+_Same(_compile, "BufferSecurityCheck", _boolean)  # /GS
+_Same(_compile, "DisableLanguageExtensions", _boolean)  # /Za
+_Same(_compile, "DisableSpecificWarnings", _string_list)  # /wd
+_Same(_compile, "EnableFiberSafeOptimizations", _boolean)  # /GT
+_Same(_compile, "EnablePREfast", _boolean)  # /analyze Visible='false'
+_Same(_compile, "ExpandAttributedSource", _boolean)  # /Fx
+_Same(_compile, "FloatingPointExceptions", _boolean)  # /fp:except
+_Same(_compile, "ForceConformanceInForLoopScope", _boolean)  # /Zc:forScope
+_Same(_compile, "ForcedIncludeFiles", _file_list)  # /FI
+_Same(_compile, "ForcedUsingFiles", _file_list)  # /FU
+_Same(_compile, "GenerateXMLDocumentationFiles", _boolean)  # /doc
+_Same(_compile, "IgnoreStandardIncludePath", _boolean)  # /X
+_Same(_compile, "MinimalRebuild", _boolean)  # /Gm
+_Same(_compile, "OmitDefaultLibName", _boolean)  # /Zl
+_Same(_compile, "OmitFramePointers", _boolean)  # /Oy
+_Same(_compile, "PreprocessorDefinitions", _string_list)  # /D
+_Same(_compile, "ProgramDataBaseFileName", _file_name)  # /Fd
+_Same(_compile, "RuntimeTypeInfo", _boolean)  # /GR
+_Same(_compile, "ShowIncludes", _boolean)  # /showIncludes
+_Same(_compile, "SmallerTypeCheck", _boolean)  # /RTCc
+_Same(_compile, "StringPooling", _boolean)  # /GF
+_Same(_compile, "SuppressStartupBanner", _boolean)  # /nologo
+_Same(_compile, "TreatWChar_tAsBuiltInType", _boolean)  # /Zc:wchar_t
+_Same(_compile, "UndefineAllPreprocessorDefinitions", _boolean)  # /u
+_Same(_compile, "UndefinePreprocessorDefinitions", _string_list)  # /U
+_Same(_compile, "UseFullPaths", _boolean)  # /FC
+_Same(_compile, "WholeProgramOptimization", _boolean)  # /GL
+_Same(_compile, "XMLDocumentationFileName", _file_name)
+_Same(_compile, "CompileAsWinRT", _boolean)  # /ZW
+
+_Same(
+    _compile,
+    "AssemblerOutput",
+    _Enumeration(
+        [
+            "NoListing",
+            "AssemblyCode",  # /FA
+            "All",  # /FAcs
+            "AssemblyAndMachineCode",  # /FAc
+            "AssemblyAndSourceCode",
+        ]
+    ),
+)  # /FAs
+_Same(
+    _compile,
+    "BasicRuntimeChecks",
+    _Enumeration(
+        [
+            "Default",
+            "StackFrameRuntimeCheck",  # /RTCs
+            "UninitializedLocalUsageCheck",  # /RTCu
+            "EnableFastChecks",
+        ]
+    ),
+)  # /RTC1
+_Same(
+    _compile, "BrowseInformation", _Enumeration(["false", "true", "true"])  # /FR
+)  # /Fr
+_Same(
+    _compile,
+    "CallingConvention",
+    _Enumeration(["Cdecl", "FastCall", "StdCall", "VectorCall"]),  # /Gd  # /Gr  # /Gz
+)  # /Gv
+_Same(
+    _compile,
+    "CompileAs",
+    _Enumeration(["Default", "CompileAsC", "CompileAsCpp"]),  # /TC
+)  # /TP
+_Same(
+    _compile,
+    "DebugInformationFormat",
+    _Enumeration(
+        [
+            "",  # Disabled
+            "OldStyle",  # /Z7
+            None,
+            "ProgramDatabase",  # /Zi
+            "EditAndContinue",
+        ]
+    ),
+)  # /ZI
+_Same(
+    _compile,
+    "EnableEnhancedInstructionSet",
+    _Enumeration(
+        [
+            "NotSet",
+            "StreamingSIMDExtensions",  # /arch:SSE
+            "StreamingSIMDExtensions2",  # /arch:SSE2
+            "AdvancedVectorExtensions",  # /arch:AVX (vs2012+)
+            "NoExtensions",  # /arch:IA32 (vs2012+)
+            # This one only exists in the new msbuild format.
+            "AdvancedVectorExtensions2",  # /arch:AVX2 (vs2013r2+)
+        ]
+    ),
+)
+_Same(
+    _compile,
+    "ErrorReporting",
+    _Enumeration(
+        [
+            "None",  # /errorReport:none
+            "Prompt",  # /errorReport:prompt
+            "Queue",
+        ],  # /errorReport:queue
+        new=["Send"],
+    ),
+)  # /errorReport:send"
+_Same(
+    _compile,
+    "ExceptionHandling",
+    _Enumeration(["false", "Sync", "Async"], new=["SyncCThrow"]),  # /EHsc  # /EHa
+)  # /EHs
+_Same(
+    _compile, "FavorSizeOrSpeed", _Enumeration(["Neither", "Speed", "Size"])  # /Ot
+)  # /Os
+_Same(
+    _compile,
+    "FloatingPointModel",
+    _Enumeration(["Precise", "Strict", "Fast"]),  # /fp:precise  # /fp:strict
+)  # /fp:fast
+_Same(
+    _compile,
+    "InlineFunctionExpansion",
+    _Enumeration(
+        ["Default", "OnlyExplicitInline", "AnySuitable"],  # /Ob1  # /Ob2
+        new=["Disabled"],
+    ),
+)  # /Ob0
+_Same(
+    _compile,
+    "Optimization",
+    _Enumeration(["Disabled", "MinSpace", "MaxSpeed", "Full"]),  # /Od  # /O1  # /O2
+)  # /Ox
+_Same(
+    _compile,
+    "RuntimeLibrary",
+    _Enumeration(
+        [
+            "MultiThreaded",  # /MT
+            "MultiThreadedDebug",  # /MTd
+            "MultiThreadedDLL",  # /MD
+            "MultiThreadedDebugDLL",
+        ]
+    ),
+)  # /MDd
+_Same(
+    _compile,
+    "StructMemberAlignment",
+    _Enumeration(
+        [
+            "Default",
+            "1Byte",  # /Zp1
+            "2Bytes",  # /Zp2
+            "4Bytes",  # /Zp4
+            "8Bytes",  # /Zp8
+            "16Bytes",
+        ]
+    ),
+)  # /Zp16
+_Same(
+    _compile,
+    "WarningLevel",
+    _Enumeration(
+        [
+            "TurnOffAllWarnings",  # /W0
+            "Level1",  # /W1
+            "Level2",  # /W2
+            "Level3",  # /W3
+            "Level4",
+        ],  # /W4
+        new=["EnableAllWarnings"],
+    ),
+)  # /Wall
+
+# Options found in MSVS that have been renamed in MSBuild.
+_Renamed(
+    _compile, "EnableFunctionLevelLinking", "FunctionLevelLinking", _boolean
+)  # /Gy
+_Renamed(_compile, "EnableIntrinsicFunctions", "IntrinsicFunctions", _boolean)  # /Oi
+_Renamed(_compile, "KeepComments", "PreprocessKeepComments", _boolean)  # /C
+_Renamed(_compile, "ObjectFile", "ObjectFileName", _file_name)  # /Fo
+_Renamed(_compile, "OpenMP", "OpenMPSupport", _boolean)  # /openmp
+_Renamed(
+    _compile, "PrecompiledHeaderThrough", "PrecompiledHeaderFile", _file_name
+)  # Used with /Yc and /Yu
+_Renamed(
+    _compile, "PrecompiledHeaderFile", "PrecompiledHeaderOutputFile", _file_name
+)  # /Fp
+_Renamed(
+    _compile,
+    "UsePrecompiledHeader",
+    "PrecompiledHeader",
+    _Enumeration(
+        ["NotUsing", "Create", "Use"]  # VS recognized '' for this value too.  # /Yc
+    ),
+)  # /Yu
+_Renamed(_compile, "WarnAsError", "TreatWarningAsError", _boolean)  # /WX
+
+_ConvertedToAdditionalOption(_compile, "DefaultCharIsUnsigned", "/J")
+
+# MSVS options not found in MSBuild.
+_MSVSOnly(_compile, "Detect64BitPortabilityProblems", _boolean)
+_MSVSOnly(_compile, "UseUnicodeResponseFiles", _boolean)
+
+# MSBuild options not found in MSVS.
+_MSBuildOnly(_compile, "BuildingInIDE", _boolean)
+_MSBuildOnly(
+    _compile, "CompileAsManaged", _Enumeration([], new=["false", "true"])
+)  # /clr
+_MSBuildOnly(_compile, "CreateHotpatchableImage", _boolean)  # /hotpatch
+_MSBuildOnly(_compile, "MultiProcessorCompilation", _boolean)  # /MP
+_MSBuildOnly(_compile, "PreprocessOutputPath", _string)  # /Fi
+_MSBuildOnly(_compile, "ProcessorNumber", _integer)  # the number of processors
+_MSBuildOnly(_compile, "TrackerLogDirectory", _folder_name)
+_MSBuildOnly(_compile, "TreatSpecificWarningsAsErrors", _string_list)  # /we
+_MSBuildOnly(_compile, "UseUnicodeForAssemblerListing", _boolean)  # /FAu
+
+# Defines a setting that needs very customized processing
+_CustomGeneratePreprocessedFile(_compile, "GeneratePreprocessedFile")
+
+
+# Directives for converting MSVS VCLinkerTool to MSBuild Link.
+# See "c:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\1033\link.xml" for
+# the schema of the MSBuild Link settings.
+
+# Options that have the same name in MSVS and MSBuild
+_Same(_link, "AdditionalDependencies", _file_list)
+_Same(_link, "AdditionalLibraryDirectories", _folder_list)  # /LIBPATH
+#  /MANIFESTDEPENDENCY:
+_Same(_link, "AdditionalManifestDependencies", _file_list)
+_Same(_link, "AdditionalOptions", _string_list)
+_Same(_link, "AddModuleNamesToAssembly", _file_list)  # /ASSEMBLYMODULE
+_Same(_link, "AllowIsolation", _boolean)  # /ALLOWISOLATION
+_Same(_link, "AssemblyLinkResource", _file_list)  # /ASSEMBLYLINKRESOURCE
+_Same(_link, "BaseAddress", _string)  # /BASE
+_Same(_link, "CLRUnmanagedCodeCheck", _boolean)  # /CLRUNMANAGEDCODECHECK
+_Same(_link, "DelayLoadDLLs", _file_list)  # /DELAYLOAD
+_Same(_link, "DelaySign", _boolean)  # /DELAYSIGN
+_Same(_link, "EmbedManagedResourceFile", _file_list)  # /ASSEMBLYRESOURCE
+_Same(_link, "EnableUAC", _boolean)  # /MANIFESTUAC
+_Same(_link, "EntryPointSymbol", _string)  # /ENTRY
+_Same(_link, "ForceSymbolReferences", _file_list)  # /INCLUDE
+_Same(_link, "FunctionOrder", _file_name)  # /ORDER
+_Same(_link, "GenerateDebugInformation", _boolean)  # /DEBUG
+_Same(_link, "GenerateMapFile", _boolean)  # /MAP
+_Same(_link, "HeapCommitSize", _string)
+_Same(_link, "HeapReserveSize", _string)  # /HEAP
+_Same(_link, "IgnoreAllDefaultLibraries", _boolean)  # /NODEFAULTLIB
+_Same(_link, "IgnoreEmbeddedIDL", _boolean)  # /IGNOREIDL
+_Same(_link, "ImportLibrary", _file_name)  # /IMPLIB
+_Same(_link, "KeyContainer", _file_name)  # /KEYCONTAINER
+_Same(_link, "KeyFile", _file_name)  # /KEYFILE
+_Same(_link, "ManifestFile", _file_name)  # /ManifestFile
+_Same(_link, "MapExports", _boolean)  # /MAPINFO:EXPORTS
+_Same(_link, "MapFileName", _file_name)
+_Same(_link, "MergedIDLBaseFileName", _file_name)  # /IDLOUT
+_Same(_link, "MergeSections", _string)  # /MERGE
+_Same(_link, "MidlCommandFile", _file_name)  # /MIDL
+_Same(_link, "ModuleDefinitionFile", _file_name)  # /DEF
+_Same(_link, "OutputFile", _file_name)  # /OUT
+_Same(_link, "PerUserRedirection", _boolean)
+_Same(_link, "Profile", _boolean)  # /PROFILE
+_Same(_link, "ProfileGuidedDatabase", _file_name)  # /PGD
+_Same(_link, "ProgramDatabaseFile", _file_name)  # /PDB
+_Same(_link, "RegisterOutput", _boolean)
+_Same(_link, "SetChecksum", _boolean)  # /RELEASE
+_Same(_link, "StackCommitSize", _string)
+_Same(_link, "StackReserveSize", _string)  # /STACK
+_Same(_link, "StripPrivateSymbols", _file_name)  # /PDBSTRIPPED
+_Same(_link, "SupportUnloadOfDelayLoadedDLL", _boolean)  # /DELAY:UNLOAD
+_Same(_link, "SuppressStartupBanner", _boolean)  # /NOLOGO
+_Same(_link, "SwapRunFromCD", _boolean)  # /SWAPRUN:CD
+_Same(_link, "TurnOffAssemblyGeneration", _boolean)  # /NOASSEMBLY
+_Same(_link, "TypeLibraryFile", _file_name)  # /TLBOUT
+_Same(_link, "TypeLibraryResourceID", _integer)  # /TLBID
+_Same(_link, "UACUIAccess", _boolean)  # /uiAccess='true'
+_Same(_link, "Version", _string)  # /VERSION
+
+_Same(_link, "EnableCOMDATFolding", _newly_boolean)  # /OPT:ICF
+_Same(_link, "FixedBaseAddress", _newly_boolean)  # /FIXED
+_Same(_link, "LargeAddressAware", _newly_boolean)  # /LARGEADDRESSAWARE
+_Same(_link, "OptimizeReferences", _newly_boolean)  # /OPT:REF
+_Same(_link, "RandomizedBaseAddress", _newly_boolean)  # /DYNAMICBASE
+_Same(_link, "TerminalServerAware", _newly_boolean)  # /TSAWARE
+
+_subsystem_enumeration = _Enumeration(
+    [
+        "NotSet",
+        "Console",  # /SUBSYSTEM:CONSOLE
+        "Windows",  # /SUBSYSTEM:WINDOWS
+        "Native",  # /SUBSYSTEM:NATIVE
+        "EFI Application",  # /SUBSYSTEM:EFI_APPLICATION
+        "EFI Boot Service Driver",  # /SUBSYSTEM:EFI_BOOT_SERVICE_DRIVER
+        "EFI ROM",  # /SUBSYSTEM:EFI_ROM
+        "EFI Runtime",  # /SUBSYSTEM:EFI_RUNTIME_DRIVER
+        "WindowsCE",
+    ],  # /SUBSYSTEM:WINDOWSCE
+    new=["POSIX"],
+)  # /SUBSYSTEM:POSIX
+
+_target_machine_enumeration = _Enumeration(
+    [
+        "NotSet",
+        "MachineX86",  # /MACHINE:X86
+        None,
+        "MachineARM",  # /MACHINE:ARM
+        "MachineEBC",  # /MACHINE:EBC
+        "MachineIA64",  # /MACHINE:IA64
+        None,
+        "MachineMIPS",  # /MACHINE:MIPS
+        "MachineMIPS16",  # /MACHINE:MIPS16
+        "MachineMIPSFPU",  # /MACHINE:MIPSFPU
+        "MachineMIPSFPU16",  # /MACHINE:MIPSFPU16
+        None,
+        None,
+        None,
+        "MachineSH4",  # /MACHINE:SH4
+        None,
+        "MachineTHUMB",  # /MACHINE:THUMB
+        "MachineX64",
+    ]
+)  # /MACHINE:X64
+
+_Same(
+    _link, "AssemblyDebug", _Enumeration(["", "true", "false"])  # /ASSEMBLYDEBUG
+)  # /ASSEMBLYDEBUG:DISABLE
+_Same(
+    _link,
+    "CLRImageType",
+    _Enumeration(
+        [
+            "Default",
+            "ForceIJWImage",  # /CLRIMAGETYPE:IJW
+            "ForcePureILImage",  # /Switch="CLRIMAGETYPE:PURE
+            "ForceSafeILImage",
+        ]
+    ),
+)  # /Switch="CLRIMAGETYPE:SAFE
+_Same(
+    _link,
+    "CLRThreadAttribute",
+    _Enumeration(
+        [
+            "DefaultThreadingAttribute",  # /CLRTHREADATTRIBUTE:NONE
+            "MTAThreadingAttribute",  # /CLRTHREADATTRIBUTE:MTA
+            "STAThreadingAttribute",
+        ]
+    ),
+)  # /CLRTHREADATTRIBUTE:STA
+_Same(
+    _link,
+    "DataExecutionPrevention",
+    _Enumeration(["", "false", "true"]),  # /NXCOMPAT:NO
+)  # /NXCOMPAT
+_Same(
+    _link,
+    "Driver",
+    _Enumeration(["NotSet", "Driver", "UpOnly", "WDM"]),  # /Driver  # /DRIVER:UPONLY
+)  # /DRIVER:WDM
+_Same(
+    _link,
+    "LinkTimeCodeGeneration",
+    _Enumeration(
+        [
+            "Default",
+            "UseLinkTimeCodeGeneration",  # /LTCG
+            "PGInstrument",  # /LTCG:PGInstrument
+            "PGOptimization",  # /LTCG:PGOptimize
+            "PGUpdate",
+        ]
+    ),
+)  # /LTCG:PGUpdate
+_Same(
+    _link,
+    "ShowProgress",
+    _Enumeration(
+        ["NotSet", "LinkVerbose", "LinkVerboseLib"],  # /VERBOSE  # /VERBOSE:Lib
+        new=[
+            "LinkVerboseICF",  # /VERBOSE:ICF
+            "LinkVerboseREF",  # /VERBOSE:REF
+            "LinkVerboseSAFESEH",  # /VERBOSE:SAFESEH
+            "LinkVerboseCLR",
+        ],
+    ),
+)  # /VERBOSE:CLR
+_Same(_link, "SubSystem", _subsystem_enumeration)
+_Same(_link, "TargetMachine", _target_machine_enumeration)
+_Same(
+    _link,
+    "UACExecutionLevel",
+    _Enumeration(
+        [
+            "AsInvoker",  # /level='asInvoker'
+            "HighestAvailable",  # /level='highestAvailable'
+            "RequireAdministrator",
+        ]
+    ),
+)  # /level='requireAdministrator'
+_Same(_link, "MinimumRequiredVersion", _string)
+_Same(_link, "TreatLinkerWarningAsErrors", _boolean)  # /WX
+
+
+# Options found in MSVS that have been renamed in MSBuild.
+_Renamed(
+    _link,
+    "ErrorReporting",
+    "LinkErrorReporting",
+    _Enumeration(
+        [
+            "NoErrorReport",  # /ERRORREPORT:NONE
+            "PromptImmediately",  # /ERRORREPORT:PROMPT
+            "QueueForNextLogin",
+        ],  # /ERRORREPORT:QUEUE
+        new=["SendErrorReport"],
+    ),
+)  # /ERRORREPORT:SEND
+_Renamed(
+    _link, "IgnoreDefaultLibraryNames", "IgnoreSpecificDefaultLibraries", _file_list
+)  # /NODEFAULTLIB
+_Renamed(_link, "ResourceOnlyDLL", "NoEntryPoint", _boolean)  # /NOENTRY
+_Renamed(_link, "SwapRunFromNet", "SwapRunFromNET", _boolean)  # /SWAPRUN:NET
+
+_Moved(_link, "GenerateManifest", "", _boolean)
+_Moved(_link, "IgnoreImportLibrary", "", _boolean)
+_Moved(_link, "LinkIncremental", "", _newly_boolean)
+_Moved(_link, "LinkLibraryDependencies", "ProjectReference", _boolean)
+_Moved(_link, "UseLibraryDependencyInputs", "ProjectReference", _boolean)
+
+# MSVS options not found in MSBuild.
+_MSVSOnly(_link, "OptimizeForWindows98", _newly_boolean)
+_MSVSOnly(_link, "UseUnicodeResponseFiles", _boolean)
+
+# MSBuild options not found in MSVS.
+_MSBuildOnly(_link, "BuildingInIDE", _boolean)
+_MSBuildOnly(_link, "ImageHasSafeExceptionHandlers", _boolean)  # /SAFESEH
+_MSBuildOnly(_link, "LinkDLL", _boolean)  # /DLL Visible='false'
+_MSBuildOnly(_link, "LinkStatus", _boolean)  # /LTCG:STATUS
+_MSBuildOnly(_link, "PreventDllBinding", _boolean)  # /ALLOWBIND
+_MSBuildOnly(_link, "SupportNobindOfDelayLoadedDLL", _boolean)  # /DELAY:NOBIND
+_MSBuildOnly(_link, "TrackerLogDirectory", _folder_name)
+_MSBuildOnly(_link, "MSDOSStubFileName", _file_name)  # /STUB Visible='false'
+_MSBuildOnly(_link, "SectionAlignment", _integer)  # /ALIGN
+_MSBuildOnly(_link, "SpecifySectionAttributes", _string)  # /SECTION
+_MSBuildOnly(
+    _link,
+    "ForceFileOutput",
+    _Enumeration(
+        [],
+        new=[
+            "Enabled",  # /FORCE
+            # /FORCE:MULTIPLE
+            "MultiplyDefinedSymbolOnly",
+            "UndefinedSymbolOnly",
+        ],
+    ),
+)  # /FORCE:UNRESOLVED
+_MSBuildOnly(
+    _link,
+    "CreateHotPatchableImage",
+    _Enumeration(
+        [],
+        new=[
+            "Enabled",  # /FUNCTIONPADMIN
+            "X86Image",  # /FUNCTIONPADMIN:5
+            "X64Image",  # /FUNCTIONPADMIN:6
+            "ItaniumImage",
+        ],
+    ),
+)  # /FUNCTIONPADMIN:16
+_MSBuildOnly(
+    _link,
+    "CLRSupportLastError",
+    _Enumeration(
+        [],
+        new=[
+            "Enabled",  # /CLRSupportLastError
+            "Disabled",  # /CLRSupportLastError:NO
+            # /CLRSupportLastError:SYSTEMDLL
+            "SystemDlls",
+        ],
+    ),
+)
+
+
+# Directives for converting VCResourceCompilerTool to ResourceCompile.
+# See "c:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\1033\rc.xml" for
+# the schema of the MSBuild ResourceCompile settings.
+
+_Same(_rc, "AdditionalOptions", _string_list)
+_Same(_rc, "AdditionalIncludeDirectories", _folder_list)  # /I
+_Same(_rc, "Culture", _Integer(msbuild_base=16))
+_Same(_rc, "IgnoreStandardIncludePath", _boolean)  # /X
+_Same(_rc, "PreprocessorDefinitions", _string_list)  # /D
+_Same(_rc, "ResourceOutputFileName", _string)  # /fo
+_Same(_rc, "ShowProgress", _boolean)  # /v
+# There is no UI in VisualStudio 2008 to set the following properties.
+# However they are found in CL and other tools.  Include them here for
+# completeness, as they are very likely to have the same usage pattern.
+_Same(_rc, "SuppressStartupBanner", _boolean)  # /nologo
+_Same(_rc, "UndefinePreprocessorDefinitions", _string_list)  # /u
+
+# MSBuild options not found in MSVS.
+_MSBuildOnly(_rc, "NullTerminateStrings", _boolean)  # /n
+_MSBuildOnly(_rc, "TrackerLogDirectory", _folder_name)
+
+
+# Directives for converting VCMIDLTool to Midl.
+# See "c:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\1033\midl.xml" for
+# the schema of the MSBuild Midl settings.
+
+_Same(_midl, "AdditionalIncludeDirectories", _folder_list)  # /I
+_Same(_midl, "AdditionalOptions", _string_list)
+_Same(_midl, "CPreprocessOptions", _string)  # /cpp_opt
+_Same(_midl, "ErrorCheckAllocations", _boolean)  # /error allocation
+_Same(_midl, "ErrorCheckBounds", _boolean)  # /error bounds_check
+_Same(_midl, "ErrorCheckEnumRange", _boolean)  # /error enum
+_Same(_midl, "ErrorCheckRefPointers", _boolean)  # /error ref
+_Same(_midl, "ErrorCheckStubData", _boolean)  # /error stub_data
+_Same(_midl, "GenerateStublessProxies", _boolean)  # /Oicf
+_Same(_midl, "GenerateTypeLibrary", _boolean)
+_Same(_midl, "HeaderFileName", _file_name)  # /h
+_Same(_midl, "IgnoreStandardIncludePath", _boolean)  # /no_def_idir
+_Same(_midl, "InterfaceIdentifierFileName", _file_name)  # /iid
+_Same(_midl, "MkTypLibCompatible", _boolean)  # /mktyplib203
+_Same(_midl, "OutputDirectory", _string)  # /out
+_Same(_midl, "PreprocessorDefinitions", _string_list)  # /D
+_Same(_midl, "ProxyFileName", _file_name)  # /proxy
+_Same(_midl, "RedirectOutputAndErrors", _file_name)  # /o
+_Same(_midl, "SuppressStartupBanner", _boolean)  # /nologo
+_Same(_midl, "TypeLibraryName", _file_name)  # /tlb
+_Same(_midl, "UndefinePreprocessorDefinitions", _string_list)  # /U
+_Same(_midl, "WarnAsError", _boolean)  # /WX
+
+_Same(
+    _midl,
+    "DefaultCharType",
+    _Enumeration(["Unsigned", "Signed", "Ascii"]),  # /char unsigned  # /char signed
+)  # /char ascii7
+_Same(
+    _midl,
+    "TargetEnvironment",
+    _Enumeration(
+        [
+            "NotSet",
+            "Win32",  # /env win32
+            "Itanium",  # /env ia64
+            "X64",  # /env x64
+            "ARM64",  # /env arm64
+        ]
+    ),
+)
+_Same(
+    _midl,
+    "EnableErrorChecks",
+    _Enumeration(["EnableCustom", "None", "All"]),  # /error none
+)  # /error all
+_Same(
+    _midl,
+    "StructMemberAlignment",
+    _Enumeration(["NotSet", "1", "2", "4", "8"]),  # Zp1  # Zp2  # Zp4
+)  # Zp8
+_Same(
+    _midl,
+    "WarningLevel",
+    _Enumeration(["0", "1", "2", "3", "4"]),  # /W0  # /W1  # /W2  # /W3
+)  # /W4
+
+_Renamed(_midl, "DLLDataFileName", "DllDataFileName", _file_name)  # /dlldata
+_Renamed(_midl, "ValidateParameters", "ValidateAllParameters", _boolean)  # /robust
+
+# MSBuild options not found in MSVS.
+_MSBuildOnly(_midl, "ApplicationConfigurationMode", _boolean)  # /app_config
+_MSBuildOnly(_midl, "ClientStubFile", _file_name)  # /cstub
+_MSBuildOnly(
+    _midl, "GenerateClientFiles", _Enumeration([], new=["Stub", "None"])  # /client stub
+)  # /client none
+_MSBuildOnly(
+    _midl, "GenerateServerFiles", _Enumeration([], new=["Stub", "None"])  # /client stub
+)  # /client none
+_MSBuildOnly(_midl, "LocaleID", _integer)  # /lcid DECIMAL
+_MSBuildOnly(_midl, "ServerStubFile", _file_name)  # /sstub
+_MSBuildOnly(_midl, "SuppressCompilerWarnings", _boolean)  # /no_warn
+_MSBuildOnly(_midl, "TrackerLogDirectory", _folder_name)
+_MSBuildOnly(
+    _midl, "TypeLibFormat", _Enumeration([], new=["NewFormat", "OldFormat"])  # /newtlb
+)  # /oldtlb
+
+
+# Directives for converting VCLibrarianTool to Lib.
+# See "c:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\1033\lib.xml" for
+# the schema of the MSBuild Lib settings.
+
+_Same(_lib, "AdditionalDependencies", _file_list)
+_Same(_lib, "AdditionalLibraryDirectories", _folder_list)  # /LIBPATH
+_Same(_lib, "AdditionalOptions", _string_list)
+_Same(_lib, "ExportNamedFunctions", _string_list)  # /EXPORT
+_Same(_lib, "ForceSymbolReferences", _string)  # /INCLUDE
+_Same(_lib, "IgnoreAllDefaultLibraries", _boolean)  # /NODEFAULTLIB
+_Same(_lib, "IgnoreSpecificDefaultLibraries", _file_list)  # /NODEFAULTLIB
+_Same(_lib, "ModuleDefinitionFile", _file_name)  # /DEF
+_Same(_lib, "OutputFile", _file_name)  # /OUT
+_Same(_lib, "SuppressStartupBanner", _boolean)  # /NOLOGO
+_Same(_lib, "UseUnicodeResponseFiles", _boolean)
+_Same(_lib, "LinkTimeCodeGeneration", _boolean)  # /LTCG
+_Same(_lib, "TargetMachine", _target_machine_enumeration)
+
+# TODO(jeanluc) _link defines the same value that gets moved to
+# ProjectReference.  We may want to validate that they are consistent.
+_Moved(_lib, "LinkLibraryDependencies", "ProjectReference", _boolean)
+
+_MSBuildOnly(_lib, "DisplayLibrary", _string)  # /LIST Visible='false'
+_MSBuildOnly(
+    _lib,
+    "ErrorReporting",
+    _Enumeration(
+        [],
+        new=[
+            "PromptImmediately",  # /ERRORREPORT:PROMPT
+            "QueueForNextLogin",  # /ERRORREPORT:QUEUE
+            "SendErrorReport",  # /ERRORREPORT:SEND
+            "NoErrorReport",
+        ],
+    ),
+)  # /ERRORREPORT:NONE
+_MSBuildOnly(_lib, "MinimumRequiredVersion", _string)
+_MSBuildOnly(_lib, "Name", _file_name)  # /NAME
+_MSBuildOnly(_lib, "RemoveObjects", _file_list)  # /REMOVE
+_MSBuildOnly(_lib, "SubSystem", _subsystem_enumeration)
+_MSBuildOnly(_lib, "TrackerLogDirectory", _folder_name)
+_MSBuildOnly(_lib, "TreatLibWarningAsErrors", _boolean)  # /WX
+_MSBuildOnly(_lib, "Verbose", _boolean)
+
+
+# Directives for converting VCManifestTool to Mt.
+# See "c:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\1033\mt.xml" for
+# the schema of the MSBuild Lib settings.
+
+# Options that have the same name in MSVS and MSBuild
+_Same(_manifest, "AdditionalManifestFiles", _file_list)  # /manifest
+_Same(_manifest, "AdditionalOptions", _string_list)
+_Same(_manifest, "AssemblyIdentity", _string)  # /identity:
+_Same(_manifest, "ComponentFileName", _file_name)  # /dll
+_Same(_manifest, "GenerateCatalogFiles", _boolean)  # /makecdfs
+_Same(_manifest, "InputResourceManifests", _string)  # /inputresource
+_Same(_manifest, "OutputManifestFile", _file_name)  # /out
+_Same(_manifest, "RegistrarScriptFile", _file_name)  # /rgs
+_Same(_manifest, "ReplacementsFile", _file_name)  # /replacements
+_Same(_manifest, "SuppressStartupBanner", _boolean)  # /nologo
+_Same(_manifest, "TypeLibraryFile", _file_name)  # /tlb:
+_Same(_manifest, "UpdateFileHashes", _boolean)  # /hashupdate
+_Same(_manifest, "UpdateFileHashesSearchPath", _file_name)
+_Same(_manifest, "VerboseOutput", _boolean)  # /verbose
+
+# Options that have moved location.
+_MovedAndRenamed(
+    _manifest,
+    "ManifestResourceFile",
+    "ManifestResourceCompile",
+    "ResourceOutputFileName",
+    _file_name,
+)
+_Moved(_manifest, "EmbedManifest", "", _boolean)
+
+# MSVS options not found in MSBuild.
+_MSVSOnly(_manifest, "DependencyInformationFile", _file_name)
+_MSVSOnly(_manifest, "UseFAT32Workaround", _boolean)
+_MSVSOnly(_manifest, "UseUnicodeResponseFiles", _boolean)
+
+# MSBuild options not found in MSVS.
+_MSBuildOnly(_manifest, "EnableDPIAwareness", _boolean)
+_MSBuildOnly(_manifest, "GenerateCategoryTags", _boolean)  # /category
+_MSBuildOnly(
+    _manifest, "ManifestFromManagedAssembly", _file_name
+)  # /managedassemblyname
+_MSBuildOnly(_manifest, "OutputResourceManifests", _string)  # /outputresource
+_MSBuildOnly(_manifest, "SuppressDependencyElement", _boolean)  # /nodependency
+_MSBuildOnly(_manifest, "TrackerLogDirectory", _folder_name)
+
+
+# Directives for MASM.
+# See "$(VCTargetsPath)\BuildCustomizations\masm.xml" for the schema of the
+# MSBuild MASM settings.
+
+# Options that have the same name in MSVS and MSBuild.
+_Same(_masm, "UseSafeExceptionHandlers", _boolean)  # /safeseh
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSSettings_test.py b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSSettings_test.py
new file mode 100755
index 0000000..6ca0968
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSSettings_test.py
@@ -0,0 +1,1547 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Unit tests for the MSVSSettings.py file."""
+
+import unittest
+import gyp.MSVSSettings as MSVSSettings
+
+from io import StringIO
+
+
+class TestSequenceFunctions(unittest.TestCase):
+    def setUp(self):
+        self.stderr = StringIO()
+
+    def _ExpectedWarnings(self, expected):
+        """Compares recorded lines to expected warnings."""
+        self.stderr.seek(0)
+        actual = self.stderr.read().split("\n")
+        actual = [line for line in actual if line]
+        self.assertEqual(sorted(expected), sorted(actual))
+
+    def testValidateMSVSSettings_tool_names(self):
+        """Tests that only MSVS tool names are allowed."""
+        MSVSSettings.ValidateMSVSSettings(
+            {
+                "VCCLCompilerTool": {},
+                "VCLinkerTool": {},
+                "VCMIDLTool": {},
+                "foo": {},
+                "VCResourceCompilerTool": {},
+                "VCLibrarianTool": {},
+                "VCManifestTool": {},
+                "ClCompile": {},
+            },
+            self.stderr,
+        )
+        self._ExpectedWarnings(
+            ["Warning: unrecognized tool foo", "Warning: unrecognized tool ClCompile"]
+        )
+
+    def testValidateMSVSSettings_settings(self):
+        """Tests that for invalid MSVS settings."""
+        MSVSSettings.ValidateMSVSSettings(
+            {
+                "VCCLCompilerTool": {
+                    "AdditionalIncludeDirectories": "folder1;folder2",
+                    "AdditionalOptions": ["string1", "string2"],
+                    "AdditionalUsingDirectories": "folder1;folder2",
+                    "AssemblerListingLocation": "a_file_name",
+                    "AssemblerOutput": "0",
+                    "BasicRuntimeChecks": "5",
+                    "BrowseInformation": "fdkslj",
+                    "BrowseInformationFile": "a_file_name",
+                    "BufferSecurityCheck": "true",
+                    "CallingConvention": "-1",
+                    "CompileAs": "1",
+                    "DebugInformationFormat": "2",
+                    "DefaultCharIsUnsigned": "true",
+                    "Detect64BitPortabilityProblems": "true",
+                    "DisableLanguageExtensions": "true",
+                    "DisableSpecificWarnings": "string1;string2",
+                    "EnableEnhancedInstructionSet": "1",
+                    "EnableFiberSafeOptimizations": "true",
+                    "EnableFunctionLevelLinking": "true",
+                    "EnableIntrinsicFunctions": "true",
+                    "EnablePREfast": "true",
+                    "Enableprefast": "bogus",
+                    "ErrorReporting": "1",
+                    "ExceptionHandling": "1",
+                    "ExpandAttributedSource": "true",
+                    "FavorSizeOrSpeed": "1",
+                    "FloatingPointExceptions": "true",
+                    "FloatingPointModel": "1",
+                    "ForceConformanceInForLoopScope": "true",
+                    "ForcedIncludeFiles": "file1;file2",
+                    "ForcedUsingFiles": "file1;file2",
+                    "GeneratePreprocessedFile": "1",
+                    "GenerateXMLDocumentationFiles": "true",
+                    "IgnoreStandardIncludePath": "true",
+                    "InlineFunctionExpansion": "1",
+                    "KeepComments": "true",
+                    "MinimalRebuild": "true",
+                    "ObjectFile": "a_file_name",
+                    "OmitDefaultLibName": "true",
+                    "OmitFramePointers": "true",
+                    "OpenMP": "true",
+                    "Optimization": "1",
+                    "PrecompiledHeaderFile": "a_file_name",
+                    "PrecompiledHeaderThrough": "a_file_name",
+                    "PreprocessorDefinitions": "string1;string2",
+                    "ProgramDataBaseFileName": "a_file_name",
+                    "RuntimeLibrary": "1",
+                    "RuntimeTypeInfo": "true",
+                    "ShowIncludes": "true",
+                    "SmallerTypeCheck": "true",
+                    "StringPooling": "true",
+                    "StructMemberAlignment": "1",
+                    "SuppressStartupBanner": "true",
+                    "TreatWChar_tAsBuiltInType": "true",
+                    "UndefineAllPreprocessorDefinitions": "true",
+                    "UndefinePreprocessorDefinitions": "string1;string2",
+                    "UseFullPaths": "true",
+                    "UsePrecompiledHeader": "1",
+                    "UseUnicodeResponseFiles": "true",
+                    "WarnAsError": "true",
+                    "WarningLevel": "1",
+                    "WholeProgramOptimization": "true",
+                    "XMLDocumentationFileName": "a_file_name",
+                    "ZZXYZ": "bogus",
+                },
+                "VCLinkerTool": {
+                    "AdditionalDependencies": "file1;file2",
+                    "AdditionalDependencies_excluded": "file3",
+                    "AdditionalLibraryDirectories": "folder1;folder2",
+                    "AdditionalManifestDependencies": "file1;file2",
+                    "AdditionalOptions": "a string1",
+                    "AddModuleNamesToAssembly": "file1;file2",
+                    "AllowIsolation": "true",
+                    "AssemblyDebug": "2",
+                    "AssemblyLinkResource": "file1;file2",
+                    "BaseAddress": "a string1",
+                    "CLRImageType": "2",
+                    "CLRThreadAttribute": "2",
+                    "CLRUnmanagedCodeCheck": "true",
+                    "DataExecutionPrevention": "2",
+                    "DelayLoadDLLs": "file1;file2",
+                    "DelaySign": "true",
+                    "Driver": "2",
+                    "EmbedManagedResourceFile": "file1;file2",
+                    "EnableCOMDATFolding": "2",
+                    "EnableUAC": "true",
+                    "EntryPointSymbol": "a string1",
+                    "ErrorReporting": "2",
+                    "FixedBaseAddress": "2",
+                    "ForceSymbolReferences": "file1;file2",
+                    "FunctionOrder": "a_file_name",
+                    "GenerateDebugInformation": "true",
+                    "GenerateManifest": "true",
+                    "GenerateMapFile": "true",
+                    "HeapCommitSize": "a string1",
+                    "HeapReserveSize": "a string1",
+                    "IgnoreAllDefaultLibraries": "true",
+                    "IgnoreDefaultLibraryNames": "file1;file2",
+                    "IgnoreEmbeddedIDL": "true",
+                    "IgnoreImportLibrary": "true",
+                    "ImportLibrary": "a_file_name",
+                    "KeyContainer": "a_file_name",
+                    "KeyFile": "a_file_name",
+                    "LargeAddressAware": "2",
+                    "LinkIncremental": "2",
+                    "LinkLibraryDependencies": "true",
+                    "LinkTimeCodeGeneration": "2",
+                    "ManifestFile": "a_file_name",
+                    "MapExports": "true",
+                    "MapFileName": "a_file_name",
+                    "MergedIDLBaseFileName": "a_file_name",
+                    "MergeSections": "a string1",
+                    "MidlCommandFile": "a_file_name",
+                    "ModuleDefinitionFile": "a_file_name",
+                    "OptimizeForWindows98": "1",
+                    "OptimizeReferences": "2",
+                    "OutputFile": "a_file_name",
+                    "PerUserRedirection": "true",
+                    "Profile": "true",
+                    "ProfileGuidedDatabase": "a_file_name",
+                    "ProgramDatabaseFile": "a_file_name",
+                    "RandomizedBaseAddress": "2",
+                    "RegisterOutput": "true",
+                    "ResourceOnlyDLL": "true",
+                    "SetChecksum": "true",
+                    "ShowProgress": "2",
+                    "StackCommitSize": "a string1",
+                    "StackReserveSize": "a string1",
+                    "StripPrivateSymbols": "a_file_name",
+                    "SubSystem": "2",
+                    "SupportUnloadOfDelayLoadedDLL": "true",
+                    "SuppressStartupBanner": "true",
+                    "SwapRunFromCD": "true",
+                    "SwapRunFromNet": "true",
+                    "TargetMachine": "2",
+                    "TerminalServerAware": "2",
+                    "TurnOffAssemblyGeneration": "true",
+                    "TypeLibraryFile": "a_file_name",
+                    "TypeLibraryResourceID": "33",
+                    "UACExecutionLevel": "2",
+                    "UACUIAccess": "true",
+                    "UseLibraryDependencyInputs": "true",
+                    "UseUnicodeResponseFiles": "true",
+                    "Version": "a string1",
+                },
+                "VCMIDLTool": {
+                    "AdditionalIncludeDirectories": "folder1;folder2",
+                    "AdditionalOptions": "a string1",
+                    "CPreprocessOptions": "a string1",
+                    "DefaultCharType": "1",
+                    "DLLDataFileName": "a_file_name",
+                    "EnableErrorChecks": "1",
+                    "ErrorCheckAllocations": "true",
+                    "ErrorCheckBounds": "true",
+                    "ErrorCheckEnumRange": "true",
+                    "ErrorCheckRefPointers": "true",
+                    "ErrorCheckStubData": "true",
+                    "GenerateStublessProxies": "true",
+                    "GenerateTypeLibrary": "true",
+                    "HeaderFileName": "a_file_name",
+                    "IgnoreStandardIncludePath": "true",
+                    "InterfaceIdentifierFileName": "a_file_name",
+                    "MkTypLibCompatible": "true",
+                    "notgood": "bogus",
+                    "OutputDirectory": "a string1",
+                    "PreprocessorDefinitions": "string1;string2",
+                    "ProxyFileName": "a_file_name",
+                    "RedirectOutputAndErrors": "a_file_name",
+                    "StructMemberAlignment": "1",
+                    "SuppressStartupBanner": "true",
+                    "TargetEnvironment": "1",
+                    "TypeLibraryName": "a_file_name",
+                    "UndefinePreprocessorDefinitions": "string1;string2",
+                    "ValidateParameters": "true",
+                    "WarnAsError": "true",
+                    "WarningLevel": "1",
+                },
+                "VCResourceCompilerTool": {
+                    "AdditionalOptions": "a string1",
+                    "AdditionalIncludeDirectories": "folder1;folder2",
+                    "Culture": "1003",
+                    "IgnoreStandardIncludePath": "true",
+                    "notgood2": "bogus",
+                    "PreprocessorDefinitions": "string1;string2",
+                    "ResourceOutputFileName": "a string1",
+                    "ShowProgress": "true",
+                    "SuppressStartupBanner": "true",
+                    "UndefinePreprocessorDefinitions": "string1;string2",
+                },
+                "VCLibrarianTool": {
+                    "AdditionalDependencies": "file1;file2",
+                    "AdditionalLibraryDirectories": "folder1;folder2",
+                    "AdditionalOptions": "a string1",
+                    "ExportNamedFunctions": "string1;string2",
+                    "ForceSymbolReferences": "a string1",
+                    "IgnoreAllDefaultLibraries": "true",
+                    "IgnoreSpecificDefaultLibraries": "file1;file2",
+                    "LinkLibraryDependencies": "true",
+                    "ModuleDefinitionFile": "a_file_name",
+                    "OutputFile": "a_file_name",
+                    "SuppressStartupBanner": "true",
+                    "UseUnicodeResponseFiles": "true",
+                },
+                "VCManifestTool": {
+                    "AdditionalManifestFiles": "file1;file2",
+                    "AdditionalOptions": "a string1",
+                    "AssemblyIdentity": "a string1",
+                    "ComponentFileName": "a_file_name",
+                    "DependencyInformationFile": "a_file_name",
+                    "GenerateCatalogFiles": "true",
+                    "InputResourceManifests": "a string1",
+                    "ManifestResourceFile": "a_file_name",
+                    "OutputManifestFile": "a_file_name",
+                    "RegistrarScriptFile": "a_file_name",
+                    "ReplacementsFile": "a_file_name",
+                    "SuppressStartupBanner": "true",
+                    "TypeLibraryFile": "a_file_name",
+                    "UpdateFileHashes": "truel",
+                    "UpdateFileHashesSearchPath": "a_file_name",
+                    "UseFAT32Workaround": "true",
+                    "UseUnicodeResponseFiles": "true",
+                    "VerboseOutput": "true",
+                },
+            },
+            self.stderr,
+        )
+        self._ExpectedWarnings(
+            [
+                "Warning: for VCCLCompilerTool/BasicRuntimeChecks, "
+                "index value (5) not in expected range [0, 4)",
+                "Warning: for VCCLCompilerTool/BrowseInformation, "
+                "invalid literal for int() with base 10: 'fdkslj'",
+                "Warning: for VCCLCompilerTool/CallingConvention, "
+                "index value (-1) not in expected range [0, 4)",
+                "Warning: for VCCLCompilerTool/DebugInformationFormat, "
+                "converted value for 2 not specified.",
+                "Warning: unrecognized setting VCCLCompilerTool/Enableprefast",
+                "Warning: unrecognized setting VCCLCompilerTool/ZZXYZ",
+                "Warning: for VCLinkerTool/TargetMachine, "
+                "converted value for 2 not specified.",
+                "Warning: unrecognized setting VCMIDLTool/notgood",
+                "Warning: unrecognized setting VCResourceCompilerTool/notgood2",
+                "Warning: for VCManifestTool/UpdateFileHashes, "
+                "expected bool; got 'truel'"
+                "",
+            ]
+        )
+
+    def testValidateMSBuildSettings_settings(self):
+        """Tests that for invalid MSBuild settings."""
+        MSVSSettings.ValidateMSBuildSettings(
+            {
+                "ClCompile": {
+                    "AdditionalIncludeDirectories": "folder1;folder2",
+                    "AdditionalOptions": ["string1", "string2"],
+                    "AdditionalUsingDirectories": "folder1;folder2",
+                    "AssemblerListingLocation": "a_file_name",
+                    "AssemblerOutput": "NoListing",
+                    "BasicRuntimeChecks": "StackFrameRuntimeCheck",
+                    "BrowseInformation": "false",
+                    "BrowseInformationFile": "a_file_name",
+                    "BufferSecurityCheck": "true",
+                    "BuildingInIDE": "true",
+                    "CallingConvention": "Cdecl",
+                    "CompileAs": "CompileAsC",
+                    "CompileAsManaged": "true",
+                    "CreateHotpatchableImage": "true",
+                    "DebugInformationFormat": "ProgramDatabase",
+                    "DisableLanguageExtensions": "true",
+                    "DisableSpecificWarnings": "string1;string2",
+                    "EnableEnhancedInstructionSet": "StreamingSIMDExtensions",
+                    "EnableFiberSafeOptimizations": "true",
+                    "EnablePREfast": "true",
+                    "Enableprefast": "bogus",
+                    "ErrorReporting": "Prompt",
+                    "ExceptionHandling": "SyncCThrow",
+                    "ExpandAttributedSource": "true",
+                    "FavorSizeOrSpeed": "Neither",
+                    "FloatingPointExceptions": "true",
+                    "FloatingPointModel": "Precise",
+                    "ForceConformanceInForLoopScope": "true",
+                    "ForcedIncludeFiles": "file1;file2",
+                    "ForcedUsingFiles": "file1;file2",
+                    "FunctionLevelLinking": "false",
+                    "GenerateXMLDocumentationFiles": "true",
+                    "IgnoreStandardIncludePath": "true",
+                    "InlineFunctionExpansion": "OnlyExplicitInline",
+                    "IntrinsicFunctions": "false",
+                    "MinimalRebuild": "true",
+                    "MultiProcessorCompilation": "true",
+                    "ObjectFileName": "a_file_name",
+                    "OmitDefaultLibName": "true",
+                    "OmitFramePointers": "true",
+                    "OpenMPSupport": "true",
+                    "Optimization": "Disabled",
+                    "PrecompiledHeader": "NotUsing",
+                    "PrecompiledHeaderFile": "a_file_name",
+                    "PrecompiledHeaderOutputFile": "a_file_name",
+                    "PreprocessKeepComments": "true",
+                    "PreprocessorDefinitions": "string1;string2",
+                    "PreprocessOutputPath": "a string1",
+                    "PreprocessSuppressLineNumbers": "false",
+                    "PreprocessToFile": "false",
+                    "ProcessorNumber": "33",
+                    "ProgramDataBaseFileName": "a_file_name",
+                    "RuntimeLibrary": "MultiThreaded",
+                    "RuntimeTypeInfo": "true",
+                    "ShowIncludes": "true",
+                    "SmallerTypeCheck": "true",
+                    "StringPooling": "true",
+                    "StructMemberAlignment": "1Byte",
+                    "SuppressStartupBanner": "true",
+                    "TrackerLogDirectory": "a_folder",
+                    "TreatSpecificWarningsAsErrors": "string1;string2",
+                    "TreatWarningAsError": "true",
+                    "TreatWChar_tAsBuiltInType": "true",
+                    "UndefineAllPreprocessorDefinitions": "true",
+                    "UndefinePreprocessorDefinitions": "string1;string2",
+                    "UseFullPaths": "true",
+                    "UseUnicodeForAssemblerListing": "true",
+                    "WarningLevel": "TurnOffAllWarnings",
+                    "WholeProgramOptimization": "true",
+                    "XMLDocumentationFileName": "a_file_name",
+                    "ZZXYZ": "bogus",
+                },
+                "Link": {
+                    "AdditionalDependencies": "file1;file2",
+                    "AdditionalLibraryDirectories": "folder1;folder2",
+                    "AdditionalManifestDependencies": "file1;file2",
+                    "AdditionalOptions": "a string1",
+                    "AddModuleNamesToAssembly": "file1;file2",
+                    "AllowIsolation": "true",
+                    "AssemblyDebug": "",
+                    "AssemblyLinkResource": "file1;file2",
+                    "BaseAddress": "a string1",
+                    "BuildingInIDE": "true",
+                    "CLRImageType": "ForceIJWImage",
+                    "CLRSupportLastError": "Enabled",
+                    "CLRThreadAttribute": "MTAThreadingAttribute",
+                    "CLRUnmanagedCodeCheck": "true",
+                    "CreateHotPatchableImage": "X86Image",
+                    "DataExecutionPrevention": "false",
+                    "DelayLoadDLLs": "file1;file2",
+                    "DelaySign": "true",
+                    "Driver": "NotSet",
+                    "EmbedManagedResourceFile": "file1;file2",
+                    "EnableCOMDATFolding": "false",
+                    "EnableUAC": "true",
+                    "EntryPointSymbol": "a string1",
+                    "FixedBaseAddress": "false",
+                    "ForceFileOutput": "Enabled",
+                    "ForceSymbolReferences": "file1;file2",
+                    "FunctionOrder": "a_file_name",
+                    "GenerateDebugInformation": "true",
+                    "GenerateMapFile": "true",
+                    "HeapCommitSize": "a string1",
+                    "HeapReserveSize": "a string1",
+                    "IgnoreAllDefaultLibraries": "true",
+                    "IgnoreEmbeddedIDL": "true",
+                    "IgnoreSpecificDefaultLibraries": "a_file_list",
+                    "ImageHasSafeExceptionHandlers": "true",
+                    "ImportLibrary": "a_file_name",
+                    "KeyContainer": "a_file_name",
+                    "KeyFile": "a_file_name",
+                    "LargeAddressAware": "false",
+                    "LinkDLL": "true",
+                    "LinkErrorReporting": "SendErrorReport",
+                    "LinkStatus": "true",
+                    "LinkTimeCodeGeneration": "UseLinkTimeCodeGeneration",
+                    "ManifestFile": "a_file_name",
+                    "MapExports": "true",
+                    "MapFileName": "a_file_name",
+                    "MergedIDLBaseFileName": "a_file_name",
+                    "MergeSections": "a string1",
+                    "MidlCommandFile": "a_file_name",
+                    "MinimumRequiredVersion": "a string1",
+                    "ModuleDefinitionFile": "a_file_name",
+                    "MSDOSStubFileName": "a_file_name",
+                    "NoEntryPoint": "true",
+                    "OptimizeReferences": "false",
+                    "OutputFile": "a_file_name",
+                    "PerUserRedirection": "true",
+                    "PreventDllBinding": "true",
+                    "Profile": "true",
+                    "ProfileGuidedDatabase": "a_file_name",
+                    "ProgramDatabaseFile": "a_file_name",
+                    "RandomizedBaseAddress": "false",
+                    "RegisterOutput": "true",
+                    "SectionAlignment": "33",
+                    "SetChecksum": "true",
+                    "ShowProgress": "LinkVerboseREF",
+                    "SpecifySectionAttributes": "a string1",
+                    "StackCommitSize": "a string1",
+                    "StackReserveSize": "a string1",
+                    "StripPrivateSymbols": "a_file_name",
+                    "SubSystem": "Console",
+                    "SupportNobindOfDelayLoadedDLL": "true",
+                    "SupportUnloadOfDelayLoadedDLL": "true",
+                    "SuppressStartupBanner": "true",
+                    "SwapRunFromCD": "true",
+                    "SwapRunFromNET": "true",
+                    "TargetMachine": "MachineX86",
+                    "TerminalServerAware": "false",
+                    "TrackerLogDirectory": "a_folder",
+                    "TreatLinkerWarningAsErrors": "true",
+                    "TurnOffAssemblyGeneration": "true",
+                    "TypeLibraryFile": "a_file_name",
+                    "TypeLibraryResourceID": "33",
+                    "UACExecutionLevel": "AsInvoker",
+                    "UACUIAccess": "true",
+                    "Version": "a string1",
+                },
+                "ResourceCompile": {
+                    "AdditionalIncludeDirectories": "folder1;folder2",
+                    "AdditionalOptions": "a string1",
+                    "Culture": "0x236",
+                    "IgnoreStandardIncludePath": "true",
+                    "NullTerminateStrings": "true",
+                    "PreprocessorDefinitions": "string1;string2",
+                    "ResourceOutputFileName": "a string1",
+                    "ShowProgress": "true",
+                    "SuppressStartupBanner": "true",
+                    "TrackerLogDirectory": "a_folder",
+                    "UndefinePreprocessorDefinitions": "string1;string2",
+                },
+                "Midl": {
+                    "AdditionalIncludeDirectories": "folder1;folder2",
+                    "AdditionalOptions": "a string1",
+                    "ApplicationConfigurationMode": "true",
+                    "ClientStubFile": "a_file_name",
+                    "CPreprocessOptions": "a string1",
+                    "DefaultCharType": "Signed",
+                    "DllDataFileName": "a_file_name",
+                    "EnableErrorChecks": "EnableCustom",
+                    "ErrorCheckAllocations": "true",
+                    "ErrorCheckBounds": "true",
+                    "ErrorCheckEnumRange": "true",
+                    "ErrorCheckRefPointers": "true",
+                    "ErrorCheckStubData": "true",
+                    "GenerateClientFiles": "Stub",
+                    "GenerateServerFiles": "None",
+                    "GenerateStublessProxies": "true",
+                    "GenerateTypeLibrary": "true",
+                    "HeaderFileName": "a_file_name",
+                    "IgnoreStandardIncludePath": "true",
+                    "InterfaceIdentifierFileName": "a_file_name",
+                    "LocaleID": "33",
+                    "MkTypLibCompatible": "true",
+                    "OutputDirectory": "a string1",
+                    "PreprocessorDefinitions": "string1;string2",
+                    "ProxyFileName": "a_file_name",
+                    "RedirectOutputAndErrors": "a_file_name",
+                    "ServerStubFile": "a_file_name",
+                    "StructMemberAlignment": "NotSet",
+                    "SuppressCompilerWarnings": "true",
+                    "SuppressStartupBanner": "true",
+                    "TargetEnvironment": "Itanium",
+                    "TrackerLogDirectory": "a_folder",
+                    "TypeLibFormat": "NewFormat",
+                    "TypeLibraryName": "a_file_name",
+                    "UndefinePreprocessorDefinitions": "string1;string2",
+                    "ValidateAllParameters": "true",
+                    "WarnAsError": "true",
+                    "WarningLevel": "1",
+                },
+                "Lib": {
+                    "AdditionalDependencies": "file1;file2",
+                    "AdditionalLibraryDirectories": "folder1;folder2",
+                    "AdditionalOptions": "a string1",
+                    "DisplayLibrary": "a string1",
+                    "ErrorReporting": "PromptImmediately",
+                    "ExportNamedFunctions": "string1;string2",
+                    "ForceSymbolReferences": "a string1",
+                    "IgnoreAllDefaultLibraries": "true",
+                    "IgnoreSpecificDefaultLibraries": "file1;file2",
+                    "LinkTimeCodeGeneration": "true",
+                    "MinimumRequiredVersion": "a string1",
+                    "ModuleDefinitionFile": "a_file_name",
+                    "Name": "a_file_name",
+                    "OutputFile": "a_file_name",
+                    "RemoveObjects": "file1;file2",
+                    "SubSystem": "Console",
+                    "SuppressStartupBanner": "true",
+                    "TargetMachine": "MachineX86i",
+                    "TrackerLogDirectory": "a_folder",
+                    "TreatLibWarningAsErrors": "true",
+                    "UseUnicodeResponseFiles": "true",
+                    "Verbose": "true",
+                },
+                "Manifest": {
+                    "AdditionalManifestFiles": "file1;file2",
+                    "AdditionalOptions": "a string1",
+                    "AssemblyIdentity": "a string1",
+                    "ComponentFileName": "a_file_name",
+                    "EnableDPIAwareness": "fal",
+                    "GenerateCatalogFiles": "truel",
+                    "GenerateCategoryTags": "true",
+                    "InputResourceManifests": "a string1",
+                    "ManifestFromManagedAssembly": "a_file_name",
+                    "notgood3": "bogus",
+                    "OutputManifestFile": "a_file_name",
+                    "OutputResourceManifests": "a string1",
+                    "RegistrarScriptFile": "a_file_name",
+                    "ReplacementsFile": "a_file_name",
+                    "SuppressDependencyElement": "true",
+                    "SuppressStartupBanner": "true",
+                    "TrackerLogDirectory": "a_folder",
+                    "TypeLibraryFile": "a_file_name",
+                    "UpdateFileHashes": "true",
+                    "UpdateFileHashesSearchPath": "a_file_name",
+                    "VerboseOutput": "true",
+                },
+                "ProjectReference": {
+                    "LinkLibraryDependencies": "true",
+                    "UseLibraryDependencyInputs": "true",
+                },
+                "ManifestResourceCompile": {"ResourceOutputFileName": "a_file_name"},
+                "": {
+                    "EmbedManifest": "true",
+                    "GenerateManifest": "true",
+                    "IgnoreImportLibrary": "true",
+                    "LinkIncremental": "false",
+                },
+            },
+            self.stderr,
+        )
+        self._ExpectedWarnings(
+            [
+                "Warning: unrecognized setting ClCompile/Enableprefast",
+                "Warning: unrecognized setting ClCompile/ZZXYZ",
+                "Warning: unrecognized setting Manifest/notgood3",
+                "Warning: for Manifest/GenerateCatalogFiles, "
+                "expected bool; got 'truel'",
+                "Warning: for Lib/TargetMachine, unrecognized enumerated value "
+                "MachineX86i",
+                "Warning: for Manifest/EnableDPIAwareness, expected bool; got 'fal'",
+            ]
+        )
+
+    def testConvertToMSBuildSettings_empty(self):
+        """Tests an empty conversion."""
+        msvs_settings = {}
+        expected_msbuild_settings = {}
+        actual_msbuild_settings = MSVSSettings.ConvertToMSBuildSettings(
+            msvs_settings, self.stderr
+        )
+        self.assertEqual(expected_msbuild_settings, actual_msbuild_settings)
+        self._ExpectedWarnings([])
+
+    def testConvertToMSBuildSettings_minimal(self):
+        """Tests a minimal conversion."""
+        msvs_settings = {
+            "VCCLCompilerTool": {
+                "AdditionalIncludeDirectories": "dir1",
+                "AdditionalOptions": "/foo",
+                "BasicRuntimeChecks": "0",
+            },
+            "VCLinkerTool": {
+                "LinkTimeCodeGeneration": "1",
+                "ErrorReporting": "1",
+                "DataExecutionPrevention": "2",
+            },
+        }
+        expected_msbuild_settings = {
+            "ClCompile": {
+                "AdditionalIncludeDirectories": "dir1",
+                "AdditionalOptions": "/foo",
+                "BasicRuntimeChecks": "Default",
+            },
+            "Link": {
+                "LinkTimeCodeGeneration": "UseLinkTimeCodeGeneration",
+                "LinkErrorReporting": "PromptImmediately",
+                "DataExecutionPrevention": "true",
+            },
+        }
+        actual_msbuild_settings = MSVSSettings.ConvertToMSBuildSettings(
+            msvs_settings, self.stderr
+        )
+        self.assertEqual(expected_msbuild_settings, actual_msbuild_settings)
+        self._ExpectedWarnings([])
+
+    def testConvertToMSBuildSettings_warnings(self):
+        """Tests conversion that generates warnings."""
+        msvs_settings = {
+            "VCCLCompilerTool": {
+                "AdditionalIncludeDirectories": "1",
+                "AdditionalOptions": "2",
+                # These are incorrect values:
+                "BasicRuntimeChecks": "12",
+                "BrowseInformation": "21",
+                "UsePrecompiledHeader": "13",
+                "GeneratePreprocessedFile": "14",
+            },
+            "VCLinkerTool": {
+                # These are incorrect values:
+                "Driver": "10",
+                "LinkTimeCodeGeneration": "31",
+                "ErrorReporting": "21",
+                "FixedBaseAddress": "6",
+            },
+            "VCResourceCompilerTool": {
+                # Custom
+                "Culture": "1003"
+            },
+        }
+        expected_msbuild_settings = {
+            "ClCompile": {
+                "AdditionalIncludeDirectories": "1",
+                "AdditionalOptions": "2",
+            },
+            "Link": {},
+            "ResourceCompile": {
+                # Custom
+                "Culture": "0x03eb"
+            },
+        }
+        actual_msbuild_settings = MSVSSettings.ConvertToMSBuildSettings(
+            msvs_settings, self.stderr
+        )
+        self.assertEqual(expected_msbuild_settings, actual_msbuild_settings)
+        self._ExpectedWarnings(
+            [
+                "Warning: while converting VCCLCompilerTool/BasicRuntimeChecks to "
+                "MSBuild, index value (12) not in expected range [0, 4)",
+                "Warning: while converting VCCLCompilerTool/BrowseInformation to "
+                "MSBuild, index value (21) not in expected range [0, 3)",
+                "Warning: while converting VCCLCompilerTool/UsePrecompiledHeader to "
+                "MSBuild, index value (13) not in expected range [0, 3)",
+                "Warning: while converting "
+                "VCCLCompilerTool/GeneratePreprocessedFile to "
+                "MSBuild, value must be one of [0, 1, 2]; got 14",
+                "Warning: while converting VCLinkerTool/Driver to "
+                "MSBuild, index value (10) not in expected range [0, 4)",
+                "Warning: while converting VCLinkerTool/LinkTimeCodeGeneration to "
+                "MSBuild, index value (31) not in expected range [0, 5)",
+                "Warning: while converting VCLinkerTool/ErrorReporting to "
+                "MSBuild, index value (21) not in expected range [0, 3)",
+                "Warning: while converting VCLinkerTool/FixedBaseAddress to "
+                "MSBuild, index value (6) not in expected range [0, 3)",
+            ]
+        )
+
+    def testConvertToMSBuildSettings_full_synthetic(self):
+        """Tests conversion of all the MSBuild settings."""
+        msvs_settings = {
+            "VCCLCompilerTool": {
+                "AdditionalIncludeDirectories": "folder1;folder2;folder3",
+                "AdditionalOptions": "a_string",
+                "AdditionalUsingDirectories": "folder1;folder2;folder3",
+                "AssemblerListingLocation": "a_file_name",
+                "AssemblerOutput": "0",
+                "BasicRuntimeChecks": "1",
+                "BrowseInformation": "2",
+                "BrowseInformationFile": "a_file_name",
+                "BufferSecurityCheck": "true",
+                "CallingConvention": "0",
+                "CompileAs": "1",
+                "DebugInformationFormat": "4",
+                "DefaultCharIsUnsigned": "true",
+                "Detect64BitPortabilityProblems": "true",
+                "DisableLanguageExtensions": "true",
+                "DisableSpecificWarnings": "d1;d2;d3",
+                "EnableEnhancedInstructionSet": "0",
+                "EnableFiberSafeOptimizations": "true",
+                "EnableFunctionLevelLinking": "true",
+                "EnableIntrinsicFunctions": "true",
+                "EnablePREfast": "true",
+                "ErrorReporting": "1",
+                "ExceptionHandling": "2",
+                "ExpandAttributedSource": "true",
+                "FavorSizeOrSpeed": "0",
+                "FloatingPointExceptions": "true",
+                "FloatingPointModel": "1",
+                "ForceConformanceInForLoopScope": "true",
+                "ForcedIncludeFiles": "file1;file2;file3",
+                "ForcedUsingFiles": "file1;file2;file3",
+                "GeneratePreprocessedFile": "1",
+                "GenerateXMLDocumentationFiles": "true",
+                "IgnoreStandardIncludePath": "true",
+                "InlineFunctionExpansion": "2",
+                "KeepComments": "true",
+                "MinimalRebuild": "true",
+                "ObjectFile": "a_file_name",
+                "OmitDefaultLibName": "true",
+                "OmitFramePointers": "true",
+                "OpenMP": "true",
+                "Optimization": "3",
+                "PrecompiledHeaderFile": "a_file_name",
+                "PrecompiledHeaderThrough": "a_file_name",
+                "PreprocessorDefinitions": "d1;d2;d3",
+                "ProgramDataBaseFileName": "a_file_name",
+                "RuntimeLibrary": "0",
+                "RuntimeTypeInfo": "true",
+                "ShowIncludes": "true",
+                "SmallerTypeCheck": "true",
+                "StringPooling": "true",
+                "StructMemberAlignment": "1",
+                "SuppressStartupBanner": "true",
+                "TreatWChar_tAsBuiltInType": "true",
+                "UndefineAllPreprocessorDefinitions": "true",
+                "UndefinePreprocessorDefinitions": "d1;d2;d3",
+                "UseFullPaths": "true",
+                "UsePrecompiledHeader": "1",
+                "UseUnicodeResponseFiles": "true",
+                "WarnAsError": "true",
+                "WarningLevel": "2",
+                "WholeProgramOptimization": "true",
+                "XMLDocumentationFileName": "a_file_name",
+            },
+            "VCLinkerTool": {
+                "AdditionalDependencies": "file1;file2;file3",
+                "AdditionalLibraryDirectories": "folder1;folder2;folder3",
+                "AdditionalLibraryDirectories_excluded": "folder1;folder2;folder3",
+                "AdditionalManifestDependencies": "file1;file2;file3",
+                "AdditionalOptions": "a_string",
+                "AddModuleNamesToAssembly": "file1;file2;file3",
+                "AllowIsolation": "true",
+                "AssemblyDebug": "0",
+                "AssemblyLinkResource": "file1;file2;file3",
+                "BaseAddress": "a_string",
+                "CLRImageType": "1",
+                "CLRThreadAttribute": "2",
+                "CLRUnmanagedCodeCheck": "true",
+                "DataExecutionPrevention": "0",
+                "DelayLoadDLLs": "file1;file2;file3",
+                "DelaySign": "true",
+                "Driver": "1",
+                "EmbedManagedResourceFile": "file1;file2;file3",
+                "EnableCOMDATFolding": "0",
+                "EnableUAC": "true",
+                "EntryPointSymbol": "a_string",
+                "ErrorReporting": "0",
+                "FixedBaseAddress": "1",
+                "ForceSymbolReferences": "file1;file2;file3",
+                "FunctionOrder": "a_file_name",
+                "GenerateDebugInformation": "true",
+                "GenerateManifest": "true",
+                "GenerateMapFile": "true",
+                "HeapCommitSize": "a_string",
+                "HeapReserveSize": "a_string",
+                "IgnoreAllDefaultLibraries": "true",
+                "IgnoreDefaultLibraryNames": "file1;file2;file3",
+                "IgnoreEmbeddedIDL": "true",
+                "IgnoreImportLibrary": "true",
+                "ImportLibrary": "a_file_name",
+                "KeyContainer": "a_file_name",
+                "KeyFile": "a_file_name",
+                "LargeAddressAware": "2",
+                "LinkIncremental": "1",
+                "LinkLibraryDependencies": "true",
+                "LinkTimeCodeGeneration": "2",
+                "ManifestFile": "a_file_name",
+                "MapExports": "true",
+                "MapFileName": "a_file_name",
+                "MergedIDLBaseFileName": "a_file_name",
+                "MergeSections": "a_string",
+                "MidlCommandFile": "a_file_name",
+                "ModuleDefinitionFile": "a_file_name",
+                "OptimizeForWindows98": "1",
+                "OptimizeReferences": "0",
+                "OutputFile": "a_file_name",
+                "PerUserRedirection": "true",
+                "Profile": "true",
+                "ProfileGuidedDatabase": "a_file_name",
+                "ProgramDatabaseFile": "a_file_name",
+                "RandomizedBaseAddress": "1",
+                "RegisterOutput": "true",
+                "ResourceOnlyDLL": "true",
+                "SetChecksum": "true",
+                "ShowProgress": "0",
+                "StackCommitSize": "a_string",
+                "StackReserveSize": "a_string",
+                "StripPrivateSymbols": "a_file_name",
+                "SubSystem": "2",
+                "SupportUnloadOfDelayLoadedDLL": "true",
+                "SuppressStartupBanner": "true",
+                "SwapRunFromCD": "true",
+                "SwapRunFromNet": "true",
+                "TargetMachine": "3",
+                "TerminalServerAware": "2",
+                "TurnOffAssemblyGeneration": "true",
+                "TypeLibraryFile": "a_file_name",
+                "TypeLibraryResourceID": "33",
+                "UACExecutionLevel": "1",
+                "UACUIAccess": "true",
+                "UseLibraryDependencyInputs": "false",
+                "UseUnicodeResponseFiles": "true",
+                "Version": "a_string",
+            },
+            "VCResourceCompilerTool": {
+                "AdditionalIncludeDirectories": "folder1;folder2;folder3",
+                "AdditionalOptions": "a_string",
+                "Culture": "1003",
+                "IgnoreStandardIncludePath": "true",
+                "PreprocessorDefinitions": "d1;d2;d3",
+                "ResourceOutputFileName": "a_string",
+                "ShowProgress": "true",
+                "SuppressStartupBanner": "true",
+                "UndefinePreprocessorDefinitions": "d1;d2;d3",
+            },
+            "VCMIDLTool": {
+                "AdditionalIncludeDirectories": "folder1;folder2;folder3",
+                "AdditionalOptions": "a_string",
+                "CPreprocessOptions": "a_string",
+                "DefaultCharType": "0",
+                "DLLDataFileName": "a_file_name",
+                "EnableErrorChecks": "2",
+                "ErrorCheckAllocations": "true",
+                "ErrorCheckBounds": "true",
+                "ErrorCheckEnumRange": "true",
+                "ErrorCheckRefPointers": "true",
+                "ErrorCheckStubData": "true",
+                "GenerateStublessProxies": "true",
+                "GenerateTypeLibrary": "true",
+                "HeaderFileName": "a_file_name",
+                "IgnoreStandardIncludePath": "true",
+                "InterfaceIdentifierFileName": "a_file_name",
+                "MkTypLibCompatible": "true",
+                "OutputDirectory": "a_string",
+                "PreprocessorDefinitions": "d1;d2;d3",
+                "ProxyFileName": "a_file_name",
+                "RedirectOutputAndErrors": "a_file_name",
+                "StructMemberAlignment": "3",
+                "SuppressStartupBanner": "true",
+                "TargetEnvironment": "1",
+                "TypeLibraryName": "a_file_name",
+                "UndefinePreprocessorDefinitions": "d1;d2;d3",
+                "ValidateParameters": "true",
+                "WarnAsError": "true",
+                "WarningLevel": "4",
+            },
+            "VCLibrarianTool": {
+                "AdditionalDependencies": "file1;file2;file3",
+                "AdditionalLibraryDirectories": "folder1;folder2;folder3",
+                "AdditionalLibraryDirectories_excluded": "folder1;folder2;folder3",
+                "AdditionalOptions": "a_string",
+                "ExportNamedFunctions": "d1;d2;d3",
+                "ForceSymbolReferences": "a_string",
+                "IgnoreAllDefaultLibraries": "true",
+                "IgnoreSpecificDefaultLibraries": "file1;file2;file3",
+                "LinkLibraryDependencies": "true",
+                "ModuleDefinitionFile": "a_file_name",
+                "OutputFile": "a_file_name",
+                "SuppressStartupBanner": "true",
+                "UseUnicodeResponseFiles": "true",
+            },
+            "VCManifestTool": {
+                "AdditionalManifestFiles": "file1;file2;file3",
+                "AdditionalOptions": "a_string",
+                "AssemblyIdentity": "a_string",
+                "ComponentFileName": "a_file_name",
+                "DependencyInformationFile": "a_file_name",
+                "EmbedManifest": "true",
+                "GenerateCatalogFiles": "true",
+                "InputResourceManifests": "a_string",
+                "ManifestResourceFile": "my_name",
+                "OutputManifestFile": "a_file_name",
+                "RegistrarScriptFile": "a_file_name",
+                "ReplacementsFile": "a_file_name",
+                "SuppressStartupBanner": "true",
+                "TypeLibraryFile": "a_file_name",
+                "UpdateFileHashes": "true",
+                "UpdateFileHashesSearchPath": "a_file_name",
+                "UseFAT32Workaround": "true",
+                "UseUnicodeResponseFiles": "true",
+                "VerboseOutput": "true",
+            },
+        }
+        expected_msbuild_settings = {
+            "ClCompile": {
+                "AdditionalIncludeDirectories": "folder1;folder2;folder3",
+                "AdditionalOptions": "a_string /J",
+                "AdditionalUsingDirectories": "folder1;folder2;folder3",
+                "AssemblerListingLocation": "a_file_name",
+                "AssemblerOutput": "NoListing",
+                "BasicRuntimeChecks": "StackFrameRuntimeCheck",
+                "BrowseInformation": "true",
+                "BrowseInformationFile": "a_file_name",
+                "BufferSecurityCheck": "true",
+                "CallingConvention": "Cdecl",
+                "CompileAs": "CompileAsC",
+                "DebugInformationFormat": "EditAndContinue",
+                "DisableLanguageExtensions": "true",
+                "DisableSpecificWarnings": "d1;d2;d3",
+                "EnableEnhancedInstructionSet": "NotSet",
+                "EnableFiberSafeOptimizations": "true",
+                "EnablePREfast": "true",
+                "ErrorReporting": "Prompt",
+                "ExceptionHandling": "Async",
+                "ExpandAttributedSource": "true",
+                "FavorSizeOrSpeed": "Neither",
+                "FloatingPointExceptions": "true",
+                "FloatingPointModel": "Strict",
+                "ForceConformanceInForLoopScope": "true",
+                "ForcedIncludeFiles": "file1;file2;file3",
+                "ForcedUsingFiles": "file1;file2;file3",
+                "FunctionLevelLinking": "true",
+                "GenerateXMLDocumentationFiles": "true",
+                "IgnoreStandardIncludePath": "true",
+                "InlineFunctionExpansion": "AnySuitable",
+                "IntrinsicFunctions": "true",
+                "MinimalRebuild": "true",
+                "ObjectFileName": "a_file_name",
+                "OmitDefaultLibName": "true",
+                "OmitFramePointers": "true",
+                "OpenMPSupport": "true",
+                "Optimization": "Full",
+                "PrecompiledHeader": "Create",
+                "PrecompiledHeaderFile": "a_file_name",
+                "PrecompiledHeaderOutputFile": "a_file_name",
+                "PreprocessKeepComments": "true",
+                "PreprocessorDefinitions": "d1;d2;d3",
+                "PreprocessSuppressLineNumbers": "false",
+                "PreprocessToFile": "true",
+                "ProgramDataBaseFileName": "a_file_name",
+                "RuntimeLibrary": "MultiThreaded",
+                "RuntimeTypeInfo": "true",
+                "ShowIncludes": "true",
+                "SmallerTypeCheck": "true",
+                "StringPooling": "true",
+                "StructMemberAlignment": "1Byte",
+                "SuppressStartupBanner": "true",
+                "TreatWarningAsError": "true",
+                "TreatWChar_tAsBuiltInType": "true",
+                "UndefineAllPreprocessorDefinitions": "true",
+                "UndefinePreprocessorDefinitions": "d1;d2;d3",
+                "UseFullPaths": "true",
+                "WarningLevel": "Level2",
+                "WholeProgramOptimization": "true",
+                "XMLDocumentationFileName": "a_file_name",
+            },
+            "Link": {
+                "AdditionalDependencies": "file1;file2;file3",
+                "AdditionalLibraryDirectories": "folder1;folder2;folder3",
+                "AdditionalManifestDependencies": "file1;file2;file3",
+                "AdditionalOptions": "a_string",
+                "AddModuleNamesToAssembly": "file1;file2;file3",
+                "AllowIsolation": "true",
+                "AssemblyDebug": "",
+                "AssemblyLinkResource": "file1;file2;file3",
+                "BaseAddress": "a_string",
+                "CLRImageType": "ForceIJWImage",
+                "CLRThreadAttribute": "STAThreadingAttribute",
+                "CLRUnmanagedCodeCheck": "true",
+                "DataExecutionPrevention": "",
+                "DelayLoadDLLs": "file1;file2;file3",
+                "DelaySign": "true",
+                "Driver": "Driver",
+                "EmbedManagedResourceFile": "file1;file2;file3",
+                "EnableCOMDATFolding": "",
+                "EnableUAC": "true",
+                "EntryPointSymbol": "a_string",
+                "FixedBaseAddress": "false",
+                "ForceSymbolReferences": "file1;file2;file3",
+                "FunctionOrder": "a_file_name",
+                "GenerateDebugInformation": "true",
+                "GenerateMapFile": "true",
+                "HeapCommitSize": "a_string",
+                "HeapReserveSize": "a_string",
+                "IgnoreAllDefaultLibraries": "true",
+                "IgnoreEmbeddedIDL": "true",
+                "IgnoreSpecificDefaultLibraries": "file1;file2;file3",
+                "ImportLibrary": "a_file_name",
+                "KeyContainer": "a_file_name",
+                "KeyFile": "a_file_name",
+                "LargeAddressAware": "true",
+                "LinkErrorReporting": "NoErrorReport",
+                "LinkTimeCodeGeneration": "PGInstrument",
+                "ManifestFile": "a_file_name",
+                "MapExports": "true",
+                "MapFileName": "a_file_name",
+                "MergedIDLBaseFileName": "a_file_name",
+                "MergeSections": "a_string",
+                "MidlCommandFile": "a_file_name",
+                "ModuleDefinitionFile": "a_file_name",
+                "NoEntryPoint": "true",
+                "OptimizeReferences": "",
+                "OutputFile": "a_file_name",
+                "PerUserRedirection": "true",
+                "Profile": "true",
+                "ProfileGuidedDatabase": "a_file_name",
+                "ProgramDatabaseFile": "a_file_name",
+                "RandomizedBaseAddress": "false",
+                "RegisterOutput": "true",
+                "SetChecksum": "true",
+                "ShowProgress": "NotSet",
+                "StackCommitSize": "a_string",
+                "StackReserveSize": "a_string",
+                "StripPrivateSymbols": "a_file_name",
+                "SubSystem": "Windows",
+                "SupportUnloadOfDelayLoadedDLL": "true",
+                "SuppressStartupBanner": "true",
+                "SwapRunFromCD": "true",
+                "SwapRunFromNET": "true",
+                "TargetMachine": "MachineARM",
+                "TerminalServerAware": "true",
+                "TurnOffAssemblyGeneration": "true",
+                "TypeLibraryFile": "a_file_name",
+                "TypeLibraryResourceID": "33",
+                "UACExecutionLevel": "HighestAvailable",
+                "UACUIAccess": "true",
+                "Version": "a_string",
+            },
+            "ResourceCompile": {
+                "AdditionalIncludeDirectories": "folder1;folder2;folder3",
+                "AdditionalOptions": "a_string",
+                "Culture": "0x03eb",
+                "IgnoreStandardIncludePath": "true",
+                "PreprocessorDefinitions": "d1;d2;d3",
+                "ResourceOutputFileName": "a_string",
+                "ShowProgress": "true",
+                "SuppressStartupBanner": "true",
+                "UndefinePreprocessorDefinitions": "d1;d2;d3",
+            },
+            "Midl": {
+                "AdditionalIncludeDirectories": "folder1;folder2;folder3",
+                "AdditionalOptions": "a_string",
+                "CPreprocessOptions": "a_string",
+                "DefaultCharType": "Unsigned",
+                "DllDataFileName": "a_file_name",
+                "EnableErrorChecks": "All",
+                "ErrorCheckAllocations": "true",
+                "ErrorCheckBounds": "true",
+                "ErrorCheckEnumRange": "true",
+                "ErrorCheckRefPointers": "true",
+                "ErrorCheckStubData": "true",
+                "GenerateStublessProxies": "true",
+                "GenerateTypeLibrary": "true",
+                "HeaderFileName": "a_file_name",
+                "IgnoreStandardIncludePath": "true",
+                "InterfaceIdentifierFileName": "a_file_name",
+                "MkTypLibCompatible": "true",
+                "OutputDirectory": "a_string",
+                "PreprocessorDefinitions": "d1;d2;d3",
+                "ProxyFileName": "a_file_name",
+                "RedirectOutputAndErrors": "a_file_name",
+                "StructMemberAlignment": "4",
+                "SuppressStartupBanner": "true",
+                "TargetEnvironment": "Win32",
+                "TypeLibraryName": "a_file_name",
+                "UndefinePreprocessorDefinitions": "d1;d2;d3",
+                "ValidateAllParameters": "true",
+                "WarnAsError": "true",
+                "WarningLevel": "4",
+            },
+            "Lib": {
+                "AdditionalDependencies": "file1;file2;file3",
+                "AdditionalLibraryDirectories": "folder1;folder2;folder3",
+                "AdditionalOptions": "a_string",
+                "ExportNamedFunctions": "d1;d2;d3",
+                "ForceSymbolReferences": "a_string",
+                "IgnoreAllDefaultLibraries": "true",
+                "IgnoreSpecificDefaultLibraries": "file1;file2;file3",
+                "ModuleDefinitionFile": "a_file_name",
+                "OutputFile": "a_file_name",
+                "SuppressStartupBanner": "true",
+                "UseUnicodeResponseFiles": "true",
+            },
+            "Manifest": {
+                "AdditionalManifestFiles": "file1;file2;file3",
+                "AdditionalOptions": "a_string",
+                "AssemblyIdentity": "a_string",
+                "ComponentFileName": "a_file_name",
+                "GenerateCatalogFiles": "true",
+                "InputResourceManifests": "a_string",
+                "OutputManifestFile": "a_file_name",
+                "RegistrarScriptFile": "a_file_name",
+                "ReplacementsFile": "a_file_name",
+                "SuppressStartupBanner": "true",
+                "TypeLibraryFile": "a_file_name",
+                "UpdateFileHashes": "true",
+                "UpdateFileHashesSearchPath": "a_file_name",
+                "VerboseOutput": "true",
+            },
+            "ManifestResourceCompile": {"ResourceOutputFileName": "my_name"},
+            "ProjectReference": {
+                "LinkLibraryDependencies": "true",
+                "UseLibraryDependencyInputs": "false",
+            },
+            "": {
+                "EmbedManifest": "true",
+                "GenerateManifest": "true",
+                "IgnoreImportLibrary": "true",
+                "LinkIncremental": "false",
+            },
+        }
+        self.maxDiff = 9999  # on failure display a long diff
+        actual_msbuild_settings = MSVSSettings.ConvertToMSBuildSettings(
+            msvs_settings, self.stderr
+        )
+        self.assertEqual(expected_msbuild_settings, actual_msbuild_settings)
+        self._ExpectedWarnings([])
+
+    def testConvertToMSBuildSettings_actual(self):
+        """Tests the conversion of an actual project.
+
+    A VS2008 project with most of the options defined was created through the
+    VS2008 IDE.  It was then converted to VS2010.  The tool settings found in
+    the .vcproj and .vcxproj files were converted to the two dictionaries
+    msvs_settings and expected_msbuild_settings.
+
+    Note that for many settings, the VS2010 converter adds macros like
+    %(AdditionalIncludeDirectories) to make sure than inherited values are
+    included.  Since the Gyp projects we generate do not use inheritance,
+    we removed these macros.  They were:
+        ClCompile:
+            AdditionalIncludeDirectories:  ';%(AdditionalIncludeDirectories)'
+            AdditionalOptions:  ' %(AdditionalOptions)'
+            AdditionalUsingDirectories:  ';%(AdditionalUsingDirectories)'
+            DisableSpecificWarnings: ';%(DisableSpecificWarnings)',
+            ForcedIncludeFiles:  ';%(ForcedIncludeFiles)',
+            ForcedUsingFiles:  ';%(ForcedUsingFiles)',
+            PreprocessorDefinitions:  ';%(PreprocessorDefinitions)',
+            UndefinePreprocessorDefinitions:
+                ';%(UndefinePreprocessorDefinitions)',
+        Link:
+            AdditionalDependencies:  ';%(AdditionalDependencies)',
+            AdditionalLibraryDirectories:  ';%(AdditionalLibraryDirectories)',
+            AdditionalManifestDependencies:
+                ';%(AdditionalManifestDependencies)',
+            AdditionalOptions:  ' %(AdditionalOptions)',
+            AddModuleNamesToAssembly:  ';%(AddModuleNamesToAssembly)',
+            AssemblyLinkResource:  ';%(AssemblyLinkResource)',
+            DelayLoadDLLs:  ';%(DelayLoadDLLs)',
+            EmbedManagedResourceFile:  ';%(EmbedManagedResourceFile)',
+            ForceSymbolReferences:  ';%(ForceSymbolReferences)',
+            IgnoreSpecificDefaultLibraries:
+                ';%(IgnoreSpecificDefaultLibraries)',
+        ResourceCompile:
+            AdditionalIncludeDirectories:  ';%(AdditionalIncludeDirectories)',
+            AdditionalOptions:  ' %(AdditionalOptions)',
+            PreprocessorDefinitions:  ';%(PreprocessorDefinitions)',
+        Manifest:
+            AdditionalManifestFiles:  ';%(AdditionalManifestFiles)',
+            AdditionalOptions:  ' %(AdditionalOptions)',
+            InputResourceManifests:  ';%(InputResourceManifests)',
+    """
+        msvs_settings = {
+            "VCCLCompilerTool": {
+                "AdditionalIncludeDirectories": "dir1",
+                "AdditionalOptions": "/more",
+                "AdditionalUsingDirectories": "test",
+                "AssemblerListingLocation": "$(IntDir)\\a",
+                "AssemblerOutput": "1",
+                "BasicRuntimeChecks": "3",
+                "BrowseInformation": "1",
+                "BrowseInformationFile": "$(IntDir)\\e",
+                "BufferSecurityCheck": "false",
+                "CallingConvention": "1",
+                "CompileAs": "1",
+                "DebugInformationFormat": "4",
+                "DefaultCharIsUnsigned": "true",
+                "Detect64BitPortabilityProblems": "true",
+                "DisableLanguageExtensions": "true",
+                "DisableSpecificWarnings": "abc",
+                "EnableEnhancedInstructionSet": "1",
+                "EnableFiberSafeOptimizations": "true",
+                "EnableFunctionLevelLinking": "true",
+                "EnableIntrinsicFunctions": "true",
+                "EnablePREfast": "true",
+                "ErrorReporting": "2",
+                "ExceptionHandling": "2",
+                "ExpandAttributedSource": "true",
+                "FavorSizeOrSpeed": "2",
+                "FloatingPointExceptions": "true",
+                "FloatingPointModel": "1",
+                "ForceConformanceInForLoopScope": "false",
+                "ForcedIncludeFiles": "def",
+                "ForcedUsingFiles": "ge",
+                "GeneratePreprocessedFile": "2",
+                "GenerateXMLDocumentationFiles": "true",
+                "IgnoreStandardIncludePath": "true",
+                "InlineFunctionExpansion": "1",
+                "KeepComments": "true",
+                "MinimalRebuild": "true",
+                "ObjectFile": "$(IntDir)\\b",
+                "OmitDefaultLibName": "true",
+                "OmitFramePointers": "true",
+                "OpenMP": "true",
+                "Optimization": "3",
+                "PrecompiledHeaderFile": "$(IntDir)\\$(TargetName).pche",
+                "PrecompiledHeaderThrough": "StdAfx.hd",
+                "PreprocessorDefinitions": "WIN32;_DEBUG;_CONSOLE",
+                "ProgramDataBaseFileName": "$(IntDir)\\vc90b.pdb",
+                "RuntimeLibrary": "3",
+                "RuntimeTypeInfo": "false",
+                "ShowIncludes": "true",
+                "SmallerTypeCheck": "true",
+                "StringPooling": "true",
+                "StructMemberAlignment": "3",
+                "SuppressStartupBanner": "false",
+                "TreatWChar_tAsBuiltInType": "false",
+                "UndefineAllPreprocessorDefinitions": "true",
+                "UndefinePreprocessorDefinitions": "wer",
+                "UseFullPaths": "true",
+                "UsePrecompiledHeader": "0",
+                "UseUnicodeResponseFiles": "false",
+                "WarnAsError": "true",
+                "WarningLevel": "3",
+                "WholeProgramOptimization": "true",
+                "XMLDocumentationFileName": "$(IntDir)\\c",
+            },
+            "VCLinkerTool": {
+                "AdditionalDependencies": "zx",
+                "AdditionalLibraryDirectories": "asd",
+                "AdditionalManifestDependencies": "s2",
+                "AdditionalOptions": "/mor2",
+                "AddModuleNamesToAssembly": "d1",
+                "AllowIsolation": "false",
+                "AssemblyDebug": "1",
+                "AssemblyLinkResource": "d5",
+                "BaseAddress": "23423",
+                "CLRImageType": "3",
+                "CLRThreadAttribute": "1",
+                "CLRUnmanagedCodeCheck": "true",
+                "DataExecutionPrevention": "0",
+                "DelayLoadDLLs": "d4",
+                "DelaySign": "true",
+                "Driver": "2",
+                "EmbedManagedResourceFile": "d2",
+                "EnableCOMDATFolding": "1",
+                "EnableUAC": "false",
+                "EntryPointSymbol": "f5",
+                "ErrorReporting": "2",
+                "FixedBaseAddress": "1",
+                "ForceSymbolReferences": "d3",
+                "FunctionOrder": "fssdfsd",
+                "GenerateDebugInformation": "true",
+                "GenerateManifest": "false",
+                "GenerateMapFile": "true",
+                "HeapCommitSize": "13",
+                "HeapReserveSize": "12",
+                "IgnoreAllDefaultLibraries": "true",
+                "IgnoreDefaultLibraryNames": "flob;flok",
+                "IgnoreEmbeddedIDL": "true",
+                "IgnoreImportLibrary": "true",
+                "ImportLibrary": "f4",
+                "KeyContainer": "f7",
+                "KeyFile": "f6",
+                "LargeAddressAware": "2",
+                "LinkIncremental": "0",
+                "LinkLibraryDependencies": "false",
+                "LinkTimeCodeGeneration": "1",
+                "ManifestFile": "$(IntDir)\\$(TargetFileName).2intermediate.manifest",
+                "MapExports": "true",
+                "MapFileName": "d5",
+                "MergedIDLBaseFileName": "f2",
+                "MergeSections": "f5",
+                "MidlCommandFile": "f1",
+                "ModuleDefinitionFile": "sdsd",
+                "OptimizeForWindows98": "2",
+                "OptimizeReferences": "2",
+                "OutputFile": "$(OutDir)\\$(ProjectName)2.exe",
+                "PerUserRedirection": "true",
+                "Profile": "true",
+                "ProfileGuidedDatabase": "$(TargetDir)$(TargetName).pgdd",
+                "ProgramDatabaseFile": "Flob.pdb",
+                "RandomizedBaseAddress": "1",
+                "RegisterOutput": "true",
+                "ResourceOnlyDLL": "true",
+                "SetChecksum": "false",
+                "ShowProgress": "1",
+                "StackCommitSize": "15",
+                "StackReserveSize": "14",
+                "StripPrivateSymbols": "d3",
+                "SubSystem": "1",
+                "SupportUnloadOfDelayLoadedDLL": "true",
+                "SuppressStartupBanner": "false",
+                "SwapRunFromCD": "true",
+                "SwapRunFromNet": "true",
+                "TargetMachine": "1",
+                "TerminalServerAware": "1",
+                "TurnOffAssemblyGeneration": "true",
+                "TypeLibraryFile": "f3",
+                "TypeLibraryResourceID": "12",
+                "UACExecutionLevel": "2",
+                "UACUIAccess": "true",
+                "UseLibraryDependencyInputs": "true",
+                "UseUnicodeResponseFiles": "false",
+                "Version": "333",
+            },
+            "VCResourceCompilerTool": {
+                "AdditionalIncludeDirectories": "f3",
+                "AdditionalOptions": "/more3",
+                "Culture": "3084",
+                "IgnoreStandardIncludePath": "true",
+                "PreprocessorDefinitions": "_UNICODE;UNICODE2",
+                "ResourceOutputFileName": "$(IntDir)/$(InputName)3.res",
+                "ShowProgress": "true",
+            },
+            "VCManifestTool": {
+                "AdditionalManifestFiles": "sfsdfsd",
+                "AdditionalOptions": "afdsdafsd",
+                "AssemblyIdentity": "sddfdsadfsa",
+                "ComponentFileName": "fsdfds",
+                "DependencyInformationFile": "$(IntDir)\\mt.depdfd",
+                "EmbedManifest": "false",
+                "GenerateCatalogFiles": "true",
+                "InputResourceManifests": "asfsfdafs",
+                "ManifestResourceFile":
+                    "$(IntDir)\\$(TargetFileName).embed.manifest.resfdsf",
+                "OutputManifestFile": "$(TargetPath).manifestdfs",
+                "RegistrarScriptFile": "sdfsfd",
+                "ReplacementsFile": "sdffsd",
+                "SuppressStartupBanner": "false",
+                "TypeLibraryFile": "sfsd",
+                "UpdateFileHashes": "true",
+                "UpdateFileHashesSearchPath": "sfsd",
+                "UseFAT32Workaround": "true",
+                "UseUnicodeResponseFiles": "false",
+                "VerboseOutput": "true",
+            },
+        }
+        expected_msbuild_settings = {
+            "ClCompile": {
+                "AdditionalIncludeDirectories": "dir1",
+                "AdditionalOptions": "/more /J",
+                "AdditionalUsingDirectories": "test",
+                "AssemblerListingLocation": "$(IntDir)a",
+                "AssemblerOutput": "AssemblyCode",
+                "BasicRuntimeChecks": "EnableFastChecks",
+                "BrowseInformation": "true",
+                "BrowseInformationFile": "$(IntDir)e",
+                "BufferSecurityCheck": "false",
+                "CallingConvention": "FastCall",
+                "CompileAs": "CompileAsC",
+                "DebugInformationFormat": "EditAndContinue",
+                "DisableLanguageExtensions": "true",
+                "DisableSpecificWarnings": "abc",
+                "EnableEnhancedInstructionSet": "StreamingSIMDExtensions",
+                "EnableFiberSafeOptimizations": "true",
+                "EnablePREfast": "true",
+                "ErrorReporting": "Queue",
+                "ExceptionHandling": "Async",
+                "ExpandAttributedSource": "true",
+                "FavorSizeOrSpeed": "Size",
+                "FloatingPointExceptions": "true",
+                "FloatingPointModel": "Strict",
+                "ForceConformanceInForLoopScope": "false",
+                "ForcedIncludeFiles": "def",
+                "ForcedUsingFiles": "ge",
+                "FunctionLevelLinking": "true",
+                "GenerateXMLDocumentationFiles": "true",
+                "IgnoreStandardIncludePath": "true",
+                "InlineFunctionExpansion": "OnlyExplicitInline",
+                "IntrinsicFunctions": "true",
+                "MinimalRebuild": "true",
+                "ObjectFileName": "$(IntDir)b",
+                "OmitDefaultLibName": "true",
+                "OmitFramePointers": "true",
+                "OpenMPSupport": "true",
+                "Optimization": "Full",
+                "PrecompiledHeader": "NotUsing",  # Actual conversion gives ''
+                "PrecompiledHeaderFile": "StdAfx.hd",
+                "PrecompiledHeaderOutputFile": "$(IntDir)$(TargetName).pche",
+                "PreprocessKeepComments": "true",
+                "PreprocessorDefinitions": "WIN32;_DEBUG;_CONSOLE",
+                "PreprocessSuppressLineNumbers": "true",
+                "PreprocessToFile": "true",
+                "ProgramDataBaseFileName": "$(IntDir)vc90b.pdb",
+                "RuntimeLibrary": "MultiThreadedDebugDLL",
+                "RuntimeTypeInfo": "false",
+                "ShowIncludes": "true",
+                "SmallerTypeCheck": "true",
+                "StringPooling": "true",
+                "StructMemberAlignment": "4Bytes",
+                "SuppressStartupBanner": "false",
+                "TreatWarningAsError": "true",
+                "TreatWChar_tAsBuiltInType": "false",
+                "UndefineAllPreprocessorDefinitions": "true",
+                "UndefinePreprocessorDefinitions": "wer",
+                "UseFullPaths": "true",
+                "WarningLevel": "Level3",
+                "WholeProgramOptimization": "true",
+                "XMLDocumentationFileName": "$(IntDir)c",
+            },
+            "Link": {
+                "AdditionalDependencies": "zx",
+                "AdditionalLibraryDirectories": "asd",
+                "AdditionalManifestDependencies": "s2",
+                "AdditionalOptions": "/mor2",
+                "AddModuleNamesToAssembly": "d1",
+                "AllowIsolation": "false",
+                "AssemblyDebug": "true",
+                "AssemblyLinkResource": "d5",
+                "BaseAddress": "23423",
+                "CLRImageType": "ForceSafeILImage",
+                "CLRThreadAttribute": "MTAThreadingAttribute",
+                "CLRUnmanagedCodeCheck": "true",
+                "DataExecutionPrevention": "",
+                "DelayLoadDLLs": "d4",
+                "DelaySign": "true",
+                "Driver": "UpOnly",
+                "EmbedManagedResourceFile": "d2",
+                "EnableCOMDATFolding": "false",
+                "EnableUAC": "false",
+                "EntryPointSymbol": "f5",
+                "FixedBaseAddress": "false",
+                "ForceSymbolReferences": "d3",
+                "FunctionOrder": "fssdfsd",
+                "GenerateDebugInformation": "true",
+                "GenerateMapFile": "true",
+                "HeapCommitSize": "13",
+                "HeapReserveSize": "12",
+                "IgnoreAllDefaultLibraries": "true",
+                "IgnoreEmbeddedIDL": "true",
+                "IgnoreSpecificDefaultLibraries": "flob;flok",
+                "ImportLibrary": "f4",
+                "KeyContainer": "f7",
+                "KeyFile": "f6",
+                "LargeAddressAware": "true",
+                "LinkErrorReporting": "QueueForNextLogin",
+                "LinkTimeCodeGeneration": "UseLinkTimeCodeGeneration",
+                "ManifestFile": "$(IntDir)$(TargetFileName).2intermediate.manifest",
+                "MapExports": "true",
+                "MapFileName": "d5",
+                "MergedIDLBaseFileName": "f2",
+                "MergeSections": "f5",
+                "MidlCommandFile": "f1",
+                "ModuleDefinitionFile": "sdsd",
+                "NoEntryPoint": "true",
+                "OptimizeReferences": "true",
+                "OutputFile": "$(OutDir)$(ProjectName)2.exe",
+                "PerUserRedirection": "true",
+                "Profile": "true",
+                "ProfileGuidedDatabase": "$(TargetDir)$(TargetName).pgdd",
+                "ProgramDatabaseFile": "Flob.pdb",
+                "RandomizedBaseAddress": "false",
+                "RegisterOutput": "true",
+                "SetChecksum": "false",
+                "ShowProgress": "LinkVerbose",
+                "StackCommitSize": "15",
+                "StackReserveSize": "14",
+                "StripPrivateSymbols": "d3",
+                "SubSystem": "Console",
+                "SupportUnloadOfDelayLoadedDLL": "true",
+                "SuppressStartupBanner": "false",
+                "SwapRunFromCD": "true",
+                "SwapRunFromNET": "true",
+                "TargetMachine": "MachineX86",
+                "TerminalServerAware": "false",
+                "TurnOffAssemblyGeneration": "true",
+                "TypeLibraryFile": "f3",
+                "TypeLibraryResourceID": "12",
+                "UACExecutionLevel": "RequireAdministrator",
+                "UACUIAccess": "true",
+                "Version": "333",
+            },
+            "ResourceCompile": {
+                "AdditionalIncludeDirectories": "f3",
+                "AdditionalOptions": "/more3",
+                "Culture": "0x0c0c",
+                "IgnoreStandardIncludePath": "true",
+                "PreprocessorDefinitions": "_UNICODE;UNICODE2",
+                "ResourceOutputFileName": "$(IntDir)%(Filename)3.res",
+                "ShowProgress": "true",
+            },
+            "Manifest": {
+                "AdditionalManifestFiles": "sfsdfsd",
+                "AdditionalOptions": "afdsdafsd",
+                "AssemblyIdentity": "sddfdsadfsa",
+                "ComponentFileName": "fsdfds",
+                "GenerateCatalogFiles": "true",
+                "InputResourceManifests": "asfsfdafs",
+                "OutputManifestFile": "$(TargetPath).manifestdfs",
+                "RegistrarScriptFile": "sdfsfd",
+                "ReplacementsFile": "sdffsd",
+                "SuppressStartupBanner": "false",
+                "TypeLibraryFile": "sfsd",
+                "UpdateFileHashes": "true",
+                "UpdateFileHashesSearchPath": "sfsd",
+                "VerboseOutput": "true",
+            },
+            "ProjectReference": {
+                "LinkLibraryDependencies": "false",
+                "UseLibraryDependencyInputs": "true",
+            },
+            "": {
+                "EmbedManifest": "false",
+                "GenerateManifest": "false",
+                "IgnoreImportLibrary": "true",
+                "LinkIncremental": "",
+            },
+            "ManifestResourceCompile": {
+                "ResourceOutputFileName":
+                    "$(IntDir)$(TargetFileName).embed.manifest.resfdsf"
+            },
+        }
+        self.maxDiff = 9999  # on failure display a long diff
+        actual_msbuild_settings = MSVSSettings.ConvertToMSBuildSettings(
+            msvs_settings, self.stderr
+        )
+        self.assertEqual(expected_msbuild_settings, actual_msbuild_settings)
+        self._ExpectedWarnings([])
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSToolFile.py b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSToolFile.py
new file mode 100644
index 0000000..2e5c811
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSToolFile.py
@@ -0,0 +1,59 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Visual Studio project reader/writer."""
+
+import gyp.easy_xml as easy_xml
+
+
+class Writer:
+    """Visual Studio XML tool file writer."""
+
+    def __init__(self, tool_file_path, name):
+        """Initializes the tool file.
+
+    Args:
+      tool_file_path: Path to the tool file.
+      name: Name of the tool file.
+    """
+        self.tool_file_path = tool_file_path
+        self.name = name
+        self.rules_section = ["Rules"]
+
+    def AddCustomBuildRule(
+        self, name, cmd, description, additional_dependencies, outputs, extensions
+    ):
+        """Adds a rule to the tool file.
+
+    Args:
+      name: Name of the rule.
+      description: Description of the rule.
+      cmd: Command line of the rule.
+      additional_dependencies: other files which may trigger the rule.
+      outputs: outputs of the rule.
+      extensions: extensions handled by the rule.
+    """
+        rule = [
+            "CustomBuildRule",
+            {
+                "Name": name,
+                "ExecutionDescription": description,
+                "CommandLine": cmd,
+                "Outputs": ";".join(outputs),
+                "FileExtensions": ";".join(extensions),
+                "AdditionalDependencies": ";".join(additional_dependencies),
+            },
+        ]
+        self.rules_section.append(rule)
+
+    def WriteIfChanged(self):
+        """Writes the tool file."""
+        content = [
+            "VisualStudioToolFile",
+            {"Version": "8.00", "Name": self.name},
+            self.rules_section,
+        ]
+        easy_xml.WriteXmlIfChanged(
+            content, self.tool_file_path, encoding="Windows-1252"
+        )
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSUserFile.py b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSUserFile.py
new file mode 100644
index 0000000..e580c00
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSUserFile.py
@@ -0,0 +1,153 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Visual Studio user preferences file writer."""
+
+import os
+import re
+import socket  # for gethostname
+
+import gyp.easy_xml as easy_xml
+
+
+# ------------------------------------------------------------------------------
+
+
+def _FindCommandInPath(command):
+    """If there are no slashes in the command given, this function
+     searches the PATH env to find the given command, and converts it
+     to an absolute path.  We have to do this because MSVS is looking
+     for an actual file to launch a debugger on, not just a command
+     line.  Note that this happens at GYP time, so anything needing to
+     be built needs to have a full path."""
+    if "/" in command or "\\" in command:
+        # If the command already has path elements (either relative or
+        # absolute), then assume it is constructed properly.
+        return command
+    else:
+        # Search through the path list and find an existing file that
+        # we can access.
+        paths = os.environ.get("PATH", "").split(os.pathsep)
+        for path in paths:
+            item = os.path.join(path, command)
+            if os.path.isfile(item) and os.access(item, os.X_OK):
+                return item
+    return command
+
+
+def _QuoteWin32CommandLineArgs(args):
+    new_args = []
+    for arg in args:
+        # Replace all double-quotes with double-double-quotes to escape
+        # them for cmd shell, and then quote the whole thing if there
+        # are any.
+        if arg.find('"') != -1:
+            arg = '""'.join(arg.split('"'))
+            arg = '"%s"' % arg
+
+        # Otherwise, if there are any spaces, quote the whole arg.
+        elif re.search(r"[ \t\n]", arg):
+            arg = '"%s"' % arg
+        new_args.append(arg)
+    return new_args
+
+
+class Writer:
+    """Visual Studio XML user user file writer."""
+
+    def __init__(self, user_file_path, version, name):
+        """Initializes the user file.
+
+    Args:
+      user_file_path: Path to the user file.
+      version: Version info.
+      name: Name of the user file.
+    """
+        self.user_file_path = user_file_path
+        self.version = version
+        self.name = name
+        self.configurations = {}
+
+    def AddConfig(self, name):
+        """Adds a configuration to the project.
+
+    Args:
+      name: Configuration name.
+    """
+        self.configurations[name] = ["Configuration", {"Name": name}]
+
+    def AddDebugSettings(
+        self, config_name, command, environment={}, working_directory=""
+    ):
+        """Adds a DebugSettings node to the user file for a particular config.
+
+    Args:
+      command: command line to run.  First element in the list is the
+        executable.  All elements of the command will be quoted if
+        necessary.
+      working_directory: other files which may trigger the rule. (optional)
+    """
+        command = _QuoteWin32CommandLineArgs(command)
+
+        abs_command = _FindCommandInPath(command[0])
+
+        if environment and isinstance(environment, dict):
+            env_list = [f'{key}="{val}"' for (key, val) in environment.items()]
+            environment = " ".join(env_list)
+        else:
+            environment = ""
+
+        n_cmd = [
+            "DebugSettings",
+            {
+                "Command": abs_command,
+                "WorkingDirectory": working_directory,
+                "CommandArguments": " ".join(command[1:]),
+                "RemoteMachine": socket.gethostname(),
+                "Environment": environment,
+                "EnvironmentMerge": "true",
+                # Currently these are all "dummy" values that we're just setting
+                # in the default manner that MSVS does it.  We could use some of
+                # these to add additional capabilities, I suppose, but they might
+                # not have parity with other platforms then.
+                "Attach": "false",
+                "DebuggerType": "3",  # 'auto' debugger
+                "Remote": "1",
+                "RemoteCommand": "",
+                "HttpUrl": "",
+                "PDBPath": "",
+                "SQLDebugging": "",
+                "DebuggerFlavor": "0",
+                "MPIRunCommand": "",
+                "MPIRunArguments": "",
+                "MPIRunWorkingDirectory": "",
+                "ApplicationCommand": "",
+                "ApplicationArguments": "",
+                "ShimCommand": "",
+                "MPIAcceptMode": "",
+                "MPIAcceptFilter": "",
+            },
+        ]
+
+        # Find the config, and add it if it doesn't exist.
+        if config_name not in self.configurations:
+            self.AddConfig(config_name)
+
+        # Add the DebugSettings onto the appropriate config.
+        self.configurations[config_name].append(n_cmd)
+
+    def WriteIfChanged(self):
+        """Writes the user file."""
+        configs = ["Configurations"]
+        for config, spec in sorted(self.configurations.items()):
+            configs.append(spec)
+
+        content = [
+            "VisualStudioUserFile",
+            {"Version": self.version.ProjectVersion(), "Name": self.name},
+            configs,
+        ]
+        easy_xml.WriteXmlIfChanged(
+            content, self.user_file_path, encoding="Windows-1252"
+        )
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSUtil.py b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSUtil.py
new file mode 100644
index 0000000..36bb782
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSUtil.py
@@ -0,0 +1,271 @@
+# Copyright (c) 2013 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Utility functions shared amongst the Windows generators."""
+
+import copy
+import os
+
+
+# A dictionary mapping supported target types to extensions.
+TARGET_TYPE_EXT = {
+    "executable": "exe",
+    "loadable_module": "dll",
+    "shared_library": "dll",
+    "static_library": "lib",
+    "windows_driver": "sys",
+}
+
+
+def _GetLargePdbShimCcPath():
+    """Returns the path of the large_pdb_shim.cc file."""
+    this_dir = os.path.abspath(os.path.dirname(__file__))
+    src_dir = os.path.abspath(os.path.join(this_dir, "..", ".."))
+    win_data_dir = os.path.join(src_dir, "data", "win")
+    large_pdb_shim_cc = os.path.join(win_data_dir, "large-pdb-shim.cc")
+    return large_pdb_shim_cc
+
+
+def _DeepCopySomeKeys(in_dict, keys):
+    """Performs a partial deep-copy on |in_dict|, only copying the keys in |keys|.
+
+  Arguments:
+    in_dict: The dictionary to copy.
+    keys: The keys to be copied. If a key is in this list and doesn't exist in
+        |in_dict| this is not an error.
+  Returns:
+    The partially deep-copied dictionary.
+  """
+    d = {}
+    for key in keys:
+        if key not in in_dict:
+            continue
+        d[key] = copy.deepcopy(in_dict[key])
+    return d
+
+
+def _SuffixName(name, suffix):
+    """Add a suffix to the end of a target.
+
+  Arguments:
+    name: name of the target (foo#target)
+    suffix: the suffix to be added
+  Returns:
+    Target name with suffix added (foo_suffix#target)
+  """
+    parts = name.rsplit("#", 1)
+    parts[0] = f"{parts[0]}_{suffix}"
+    return "#".join(parts)
+
+
+def _ShardName(name, number):
+    """Add a shard number to the end of a target.
+
+  Arguments:
+    name: name of the target (foo#target)
+    number: shard number
+  Returns:
+    Target name with shard added (foo_1#target)
+  """
+    return _SuffixName(name, str(number))
+
+
+def ShardTargets(target_list, target_dicts):
+    """Shard some targets apart to work around the linkers limits.
+
+  Arguments:
+    target_list: List of target pairs: 'base/base.gyp:base'.
+    target_dicts: Dict of target properties keyed on target pair.
+  Returns:
+    Tuple of the new sharded versions of the inputs.
+  """
+    # Gather the targets to shard, and how many pieces.
+    targets_to_shard = {}
+    for t in target_dicts:
+        shards = int(target_dicts[t].get("msvs_shard", 0))
+        if shards:
+            targets_to_shard[t] = shards
+    # Shard target_list.
+    new_target_list = []
+    for t in target_list:
+        if t in targets_to_shard:
+            for i in range(targets_to_shard[t]):
+                new_target_list.append(_ShardName(t, i))
+        else:
+            new_target_list.append(t)
+    # Shard target_dict.
+    new_target_dicts = {}
+    for t in target_dicts:
+        if t in targets_to_shard:
+            for i in range(targets_to_shard[t]):
+                name = _ShardName(t, i)
+                new_target_dicts[name] = copy.copy(target_dicts[t])
+                new_target_dicts[name]["target_name"] = _ShardName(
+                    new_target_dicts[name]["target_name"], i
+                )
+                sources = new_target_dicts[name].get("sources", [])
+                new_sources = []
+                for pos in range(i, len(sources), targets_to_shard[t]):
+                    new_sources.append(sources[pos])
+                new_target_dicts[name]["sources"] = new_sources
+        else:
+            new_target_dicts[t] = target_dicts[t]
+    # Shard dependencies.
+    for t in sorted(new_target_dicts):
+        for deptype in ("dependencies", "dependencies_original"):
+            dependencies = copy.copy(new_target_dicts[t].get(deptype, []))
+            new_dependencies = []
+            for d in dependencies:
+                if d in targets_to_shard:
+                    for i in range(targets_to_shard[d]):
+                        new_dependencies.append(_ShardName(d, i))
+                else:
+                    new_dependencies.append(d)
+            new_target_dicts[t][deptype] = new_dependencies
+
+    return (new_target_list, new_target_dicts)
+
+
+def _GetPdbPath(target_dict, config_name, vars):
+    """Returns the path to the PDB file that will be generated by a given
+  configuration.
+
+  The lookup proceeds as follows:
+    - Look for an explicit path in the VCLinkerTool configuration block.
+    - Look for an 'msvs_large_pdb_path' variable.
+    - Use '<(PRODUCT_DIR)/<(product_name).(exe|dll).pdb' if 'product_name' is
+      specified.
+    - Use '<(PRODUCT_DIR)/<(target_name).(exe|dll).pdb'.
+
+  Arguments:
+    target_dict: The target dictionary to be searched.
+    config_name: The name of the configuration of interest.
+    vars: A dictionary of common GYP variables with generator-specific values.
+  Returns:
+    The path of the corresponding PDB file.
+  """
+    config = target_dict["configurations"][config_name]
+    msvs = config.setdefault("msvs_settings", {})
+
+    linker = msvs.get("VCLinkerTool", {})
+
+    pdb_path = linker.get("ProgramDatabaseFile")
+    if pdb_path:
+        return pdb_path
+
+    variables = target_dict.get("variables", {})
+    pdb_path = variables.get("msvs_large_pdb_path", None)
+    if pdb_path:
+        return pdb_path
+
+    pdb_base = target_dict.get("product_name", target_dict["target_name"])
+    pdb_base = "{}.{}.pdb".format(pdb_base, TARGET_TYPE_EXT[target_dict["type"]])
+    pdb_path = vars["PRODUCT_DIR"] + "/" + pdb_base
+
+    return pdb_path
+
+
+def InsertLargePdbShims(target_list, target_dicts, vars):
+    """Insert a shim target that forces the linker to use 4KB pagesize PDBs.
+
+  This is a workaround for targets with PDBs greater than 1GB in size, the
+  limit for the 1KB pagesize PDBs created by the linker by default.
+
+  Arguments:
+    target_list: List of target pairs: 'base/base.gyp:base'.
+    target_dicts: Dict of target properties keyed on target pair.
+    vars: A dictionary of common GYP variables with generator-specific values.
+  Returns:
+    Tuple of the shimmed version of the inputs.
+  """
+    # Determine which targets need shimming.
+    targets_to_shim = []
+    for t in target_dicts:
+        target_dict = target_dicts[t]
+
+        # We only want to shim targets that have msvs_large_pdb enabled.
+        if not int(target_dict.get("msvs_large_pdb", 0)):
+            continue
+        # This is intended for executable, shared_library and loadable_module
+        # targets where every configuration is set up to produce a PDB output.
+        # If any of these conditions is not true then the shim logic will fail
+        # below.
+        targets_to_shim.append(t)
+
+    large_pdb_shim_cc = _GetLargePdbShimCcPath()
+
+    for t in targets_to_shim:
+        target_dict = target_dicts[t]
+        target_name = target_dict.get("target_name")
+
+        base_dict = _DeepCopySomeKeys(
+            target_dict, ["configurations", "default_configuration", "toolset"]
+        )
+
+        # This is the dict for copying the source file (part of the GYP tree)
+        # to the intermediate directory of the project. This is necessary because
+        # we can't always build a relative path to the shim source file (on Windows
+        # GYP and the project may be on different drives), and Ninja hates absolute
+        # paths (it ends up generating the .obj and .obj.d alongside the source
+        # file, polluting GYPs tree).
+        copy_suffix = "large_pdb_copy"
+        copy_target_name = target_name + "_" + copy_suffix
+        full_copy_target_name = _SuffixName(t, copy_suffix)
+        shim_cc_basename = os.path.basename(large_pdb_shim_cc)
+        shim_cc_dir = vars["SHARED_INTERMEDIATE_DIR"] + "/" + copy_target_name
+        shim_cc_path = shim_cc_dir + "/" + shim_cc_basename
+        copy_dict = copy.deepcopy(base_dict)
+        copy_dict["target_name"] = copy_target_name
+        copy_dict["type"] = "none"
+        copy_dict["sources"] = [large_pdb_shim_cc]
+        copy_dict["copies"] = [
+            {"destination": shim_cc_dir, "files": [large_pdb_shim_cc]}
+        ]
+
+        # This is the dict for the PDB generating shim target. It depends on the
+        # copy target.
+        shim_suffix = "large_pdb_shim"
+        shim_target_name = target_name + "_" + shim_suffix
+        full_shim_target_name = _SuffixName(t, shim_suffix)
+        shim_dict = copy.deepcopy(base_dict)
+        shim_dict["target_name"] = shim_target_name
+        shim_dict["type"] = "static_library"
+        shim_dict["sources"] = [shim_cc_path]
+        shim_dict["dependencies"] = [full_copy_target_name]
+
+        # Set up the shim to output its PDB to the same location as the final linker
+        # target.
+        for config_name, config in shim_dict.get("configurations").items():
+            pdb_path = _GetPdbPath(target_dict, config_name, vars)
+
+            # A few keys that we don't want to propagate.
+            for key in ["msvs_precompiled_header", "msvs_precompiled_source", "test"]:
+                config.pop(key, None)
+
+            msvs = config.setdefault("msvs_settings", {})
+
+            # Update the compiler directives in the shim target.
+            compiler = msvs.setdefault("VCCLCompilerTool", {})
+            compiler["DebugInformationFormat"] = "3"
+            compiler["ProgramDataBaseFileName"] = pdb_path
+
+            # Set the explicit PDB path in the appropriate configuration of the
+            # original target.
+            config = target_dict["configurations"][config_name]
+            msvs = config.setdefault("msvs_settings", {})
+            linker = msvs.setdefault("VCLinkerTool", {})
+            linker["GenerateDebugInformation"] = "true"
+            linker["ProgramDatabaseFile"] = pdb_path
+
+        # Add the new targets. They must go to the beginning of the list so that
+        # the dependency generation works as expected in ninja.
+        target_list.insert(0, full_copy_target_name)
+        target_list.insert(0, full_shim_target_name)
+        target_dicts[full_copy_target_name] = copy_dict
+        target_dicts[full_shim_target_name] = shim_dict
+
+        # Update the original target to depend on the shim target.
+        target_dict.setdefault("dependencies", []).append(full_shim_target_name)
+
+    return (target_list, target_dicts)
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSVersion.py b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSVersion.py
new file mode 100644
index 0000000..8d7f21e
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/MSVSVersion.py
@@ -0,0 +1,574 @@
+# Copyright (c) 2013 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Handle version information related to Visual Stuio."""
+
+import errno
+import os
+import re
+import subprocess
+import sys
+import glob
+
+
+def JoinPath(*args):
+    return os.path.normpath(os.path.join(*args))
+
+
+class VisualStudioVersion:
+    """Information regarding a version of Visual Studio."""
+
+    def __init__(
+        self,
+        short_name,
+        description,
+        solution_version,
+        project_version,
+        flat_sln,
+        uses_vcxproj,
+        path,
+        sdk_based,
+        default_toolset=None,
+        compatible_sdks=None,
+    ):
+        self.short_name = short_name
+        self.description = description
+        self.solution_version = solution_version
+        self.project_version = project_version
+        self.flat_sln = flat_sln
+        self.uses_vcxproj = uses_vcxproj
+        self.path = path
+        self.sdk_based = sdk_based
+        self.default_toolset = default_toolset
+        compatible_sdks = compatible_sdks or []
+        compatible_sdks.sort(key=lambda v: float(v.replace("v", "")), reverse=True)
+        self.compatible_sdks = compatible_sdks
+
+    def ShortName(self):
+        return self.short_name
+
+    def Description(self):
+        """Get the full description of the version."""
+        return self.description
+
+    def SolutionVersion(self):
+        """Get the version number of the sln files."""
+        return self.solution_version
+
+    def ProjectVersion(self):
+        """Get the version number of the vcproj or vcxproj files."""
+        return self.project_version
+
+    def FlatSolution(self):
+        return self.flat_sln
+
+    def UsesVcxproj(self):
+        """Returns true if this version uses a vcxproj file."""
+        return self.uses_vcxproj
+
+    def ProjectExtension(self):
+        """Returns the file extension for the project."""
+        return self.uses_vcxproj and ".vcxproj" or ".vcproj"
+
+    def Path(self):
+        """Returns the path to Visual Studio installation."""
+        return self.path
+
+    def ToolPath(self, tool):
+        """Returns the path to a given compiler tool. """
+        return os.path.normpath(os.path.join(self.path, "VC/bin", tool))
+
+    def DefaultToolset(self):
+        """Returns the msbuild toolset version that will be used in the absence
+    of a user override."""
+        return self.default_toolset
+
+    def _SetupScriptInternal(self, target_arch):
+        """Returns a command (with arguments) to be used to set up the
+    environment."""
+        assert target_arch in ("x86", "x64"), "target_arch not supported"
+        # If WindowsSDKDir is set and SetEnv.Cmd exists then we are using the
+        # depot_tools build tools and should run SetEnv.Cmd to set up the
+        # environment. The check for WindowsSDKDir alone is not sufficient because
+        # this is set by running vcvarsall.bat.
+        sdk_dir = os.environ.get("WindowsSDKDir", "")
+        setup_path = JoinPath(sdk_dir, "Bin", "SetEnv.Cmd")
+        if self.sdk_based and sdk_dir and os.path.exists(setup_path):
+            return [setup_path, "/" + target_arch]
+
+        is_host_arch_x64 = (
+            os.environ.get("PROCESSOR_ARCHITECTURE") == "AMD64"
+            or os.environ.get("PROCESSOR_ARCHITEW6432") == "AMD64"
+        )
+
+        # For VS2017 (and newer) it's fairly easy
+        if self.short_name >= "2017":
+            script_path = JoinPath(
+                self.path, "VC", "Auxiliary", "Build", "vcvarsall.bat"
+            )
+
+            # Always use a native executable, cross-compiling if necessary.
+            host_arch = "amd64" if is_host_arch_x64 else "x86"
+            msvc_target_arch = "amd64" if target_arch == "x64" else "x86"
+            arg = host_arch
+            if host_arch != msvc_target_arch:
+                arg += "_" + msvc_target_arch
+
+            return [script_path, arg]
+
+        # We try to find the best version of the env setup batch.
+        vcvarsall = JoinPath(self.path, "VC", "vcvarsall.bat")
+        if target_arch == "x86":
+            if (
+                self.short_name >= "2013"
+                and self.short_name[-1] != "e"
+                and is_host_arch_x64
+            ):
+                # VS2013 and later, non-Express have a x64-x86 cross that we want
+                # to prefer.
+                return [vcvarsall, "amd64_x86"]
+            else:
+                # Otherwise, the standard x86 compiler. We don't use VC/vcvarsall.bat
+                # for x86 because vcvarsall calls vcvars32, which it can only find if
+                # VS??COMNTOOLS is set, which isn't guaranteed.
+                return [JoinPath(self.path, "Common7", "Tools", "vsvars32.bat")]
+        elif target_arch == "x64":
+            arg = "x86_amd64"
+            # Use the 64-on-64 compiler if we're not using an express edition and
+            # we're running on a 64bit OS.
+            if self.short_name[-1] != "e" and is_host_arch_x64:
+                arg = "amd64"
+            return [vcvarsall, arg]
+
+    def SetupScript(self, target_arch):
+        script_data = self._SetupScriptInternal(target_arch)
+        script_path = script_data[0]
+        if not os.path.exists(script_path):
+            raise Exception(
+                "%s is missing - make sure VC++ tools are installed." % script_path
+            )
+        return script_data
+
+
+def _RegistryQueryBase(sysdir, key, value):
+    """Use reg.exe to read a particular key.
+
+  While ideally we might use the win32 module, we would like gyp to be
+  python neutral, so for instance cygwin python lacks this module.
+
+  Arguments:
+    sysdir: The system subdirectory to attempt to launch reg.exe from.
+    key: The registry key to read from.
+    value: The particular value to read.
+  Return:
+    stdout from reg.exe, or None for failure.
+  """
+    # Skip if not on Windows or Python Win32 setup issue
+    if sys.platform not in ("win32", "cygwin"):
+        return None
+    # Setup params to pass to and attempt to launch reg.exe
+    cmd = [os.path.join(os.environ.get("WINDIR", ""), sysdir, "reg.exe"), "query", key]
+    if value:
+        cmd.extend(["/v", value])
+    p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    # Obtain the stdout from reg.exe, reading to the end so p.returncode is valid
+    # Note that the error text may be in [1] in some cases
+    text = p.communicate()[0].decode("utf-8")
+    # Check return code from reg.exe; officially 0==success and 1==error
+    if p.returncode:
+        return None
+    return text
+
+
+def _RegistryQuery(key, value=None):
+    r"""Use reg.exe to read a particular key through _RegistryQueryBase.
+
+  First tries to launch from %WinDir%\Sysnative to avoid WoW64 redirection. If
+  that fails, it falls back to System32.  Sysnative is available on Vista and
+  up and available on Windows Server 2003 and XP through KB patch 942589. Note
+  that Sysnative will always fail if using 64-bit python due to it being a
+  virtual directory and System32 will work correctly in the first place.
+
+  KB 942589 - http://support.microsoft.com/kb/942589/en-us.
+
+  Arguments:
+    key: The registry key.
+    value: The particular registry value to read (optional).
+  Return:
+    stdout from reg.exe, or None for failure.
+  """
+    text = None
+    try:
+        text = _RegistryQueryBase("Sysnative", key, value)
+    except OSError as e:
+        if e.errno == errno.ENOENT:
+            text = _RegistryQueryBase("System32", key, value)
+        else:
+            raise
+    return text
+
+
+def _RegistryGetValueUsingWinReg(key, value):
+    """Use the _winreg module to obtain the value of a registry key.
+
+  Args:
+    key: The registry key.
+    value: The particular registry value to read.
+  Return:
+    contents of the registry key's value, or None on failure.  Throws
+    ImportError if winreg is unavailable.
+  """
+    from winreg import HKEY_LOCAL_MACHINE, OpenKey, QueryValueEx
+    try:
+        root, subkey = key.split("\\", 1)
+        assert root == "HKLM"  # Only need HKLM for now.
+        with OpenKey(HKEY_LOCAL_MACHINE, subkey) as hkey:
+            return QueryValueEx(hkey, value)[0]
+    except OSError:
+        return None
+
+
+def _RegistryGetValue(key, value):
+    """Use _winreg or reg.exe to obtain the value of a registry key.
+
+  Using _winreg is preferable because it solves an issue on some corporate
+  environments where access to reg.exe is locked down. However, we still need
+  to fallback to reg.exe for the case where the _winreg module is not available
+  (for example in cygwin python).
+
+  Args:
+    key: The registry key.
+    value: The particular registry value to read.
+  Return:
+    contents of the registry key's value, or None on failure.
+  """
+    try:
+        return _RegistryGetValueUsingWinReg(key, value)
+    except ImportError:
+        pass
+
+    # Fallback to reg.exe if we fail to import _winreg.
+    text = _RegistryQuery(key, value)
+    if not text:
+        return None
+    # Extract value.
+    match = re.search(r"REG_\w+\s+([^\r]+)\r\n", text)
+    if not match:
+        return None
+    return match.group(1)
+
+
+def _CreateVersion(name, path, sdk_based=False):
+    """Sets up MSVS project generation.
+
+  Setup is based off the GYP_MSVS_VERSION environment variable or whatever is
+  autodetected if GYP_MSVS_VERSION is not explicitly specified. If a version is
+  passed in that doesn't match a value in versions python will throw a error.
+  """
+    if path:
+        path = os.path.normpath(path)
+    versions = {
+        "2022": VisualStudioVersion(
+            "2022",
+            "Visual Studio 2022",
+            solution_version="12.00",
+            project_version="17.0",
+            flat_sln=False,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+            default_toolset="v143",
+            compatible_sdks=["v8.1", "v10.0"],
+        ),
+        "2019": VisualStudioVersion(
+            "2019",
+            "Visual Studio 2019",
+            solution_version="12.00",
+            project_version="16.0",
+            flat_sln=False,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+            default_toolset="v142",
+            compatible_sdks=["v8.1", "v10.0"],
+        ),
+        "2017": VisualStudioVersion(
+            "2017",
+            "Visual Studio 2017",
+            solution_version="12.00",
+            project_version="15.0",
+            flat_sln=False,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+            default_toolset="v141",
+            compatible_sdks=["v8.1", "v10.0"],
+        ),
+        "2015": VisualStudioVersion(
+            "2015",
+            "Visual Studio 2015",
+            solution_version="12.00",
+            project_version="14.0",
+            flat_sln=False,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+            default_toolset="v140",
+        ),
+        "2013": VisualStudioVersion(
+            "2013",
+            "Visual Studio 2013",
+            solution_version="13.00",
+            project_version="12.0",
+            flat_sln=False,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+            default_toolset="v120",
+        ),
+        "2013e": VisualStudioVersion(
+            "2013e",
+            "Visual Studio 2013",
+            solution_version="13.00",
+            project_version="12.0",
+            flat_sln=True,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+            default_toolset="v120",
+        ),
+        "2012": VisualStudioVersion(
+            "2012",
+            "Visual Studio 2012",
+            solution_version="12.00",
+            project_version="4.0",
+            flat_sln=False,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+            default_toolset="v110",
+        ),
+        "2012e": VisualStudioVersion(
+            "2012e",
+            "Visual Studio 2012",
+            solution_version="12.00",
+            project_version="4.0",
+            flat_sln=True,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+            default_toolset="v110",
+        ),
+        "2010": VisualStudioVersion(
+            "2010",
+            "Visual Studio 2010",
+            solution_version="11.00",
+            project_version="4.0",
+            flat_sln=False,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+        ),
+        "2010e": VisualStudioVersion(
+            "2010e",
+            "Visual C++ Express 2010",
+            solution_version="11.00",
+            project_version="4.0",
+            flat_sln=True,
+            uses_vcxproj=True,
+            path=path,
+            sdk_based=sdk_based,
+        ),
+        "2008": VisualStudioVersion(
+            "2008",
+            "Visual Studio 2008",
+            solution_version="10.00",
+            project_version="9.00",
+            flat_sln=False,
+            uses_vcxproj=False,
+            path=path,
+            sdk_based=sdk_based,
+        ),
+        "2008e": VisualStudioVersion(
+            "2008e",
+            "Visual Studio 2008",
+            solution_version="10.00",
+            project_version="9.00",
+            flat_sln=True,
+            uses_vcxproj=False,
+            path=path,
+            sdk_based=sdk_based,
+        ),
+        "2005": VisualStudioVersion(
+            "2005",
+            "Visual Studio 2005",
+            solution_version="9.00",
+            project_version="8.00",
+            flat_sln=False,
+            uses_vcxproj=False,
+            path=path,
+            sdk_based=sdk_based,
+        ),
+        "2005e": VisualStudioVersion(
+            "2005e",
+            "Visual Studio 2005",
+            solution_version="9.00",
+            project_version="8.00",
+            flat_sln=True,
+            uses_vcxproj=False,
+            path=path,
+            sdk_based=sdk_based,
+        ),
+    }
+    return versions[str(name)]
+
+
+def _ConvertToCygpath(path):
+    """Convert to cygwin path if we are using cygwin."""
+    if sys.platform == "cygwin":
+        p = subprocess.Popen(["cygpath", path], stdout=subprocess.PIPE)
+        path = p.communicate()[0].decode("utf-8").strip()
+    return path
+
+
+def _DetectVisualStudioVersions(versions_to_check, force_express):
+    """Collect the list of installed visual studio versions.
+
+  Returns:
+    A list of visual studio versions installed in descending order of
+    usage preference.
+    Base this on the registry and a quick check if devenv.exe exists.
+    Possibilities are:
+      2005(e) - Visual Studio 2005 (8)
+      2008(e) - Visual Studio 2008 (9)
+      2010(e) - Visual Studio 2010 (10)
+      2012(e) - Visual Studio 2012 (11)
+      2013(e) - Visual Studio 2013 (12)
+      2015    - Visual Studio 2015 (14)
+      2017    - Visual Studio 2017 (15)
+      2019    - Visual Studio 2019 (16)
+      2022    - Visual Studio 2022 (17)
+    Where (e) is e for express editions of MSVS and blank otherwise.
+  """
+    version_to_year = {
+        "8.0": "2005",
+        "9.0": "2008",
+        "10.0": "2010",
+        "11.0": "2012",
+        "12.0": "2013",
+        "14.0": "2015",
+        "15.0": "2017",
+        "16.0": "2019",
+        "17.0": "2022",
+    }
+    versions = []
+    for version in versions_to_check:
+        # Old method of searching for which VS version is installed
+        # We don't use the 2010-encouraged-way because we also want to get the
+        # path to the binaries, which it doesn't offer.
+        keys = [
+            r"HKLM\Software\Microsoft\VisualStudio\%s" % version,
+            r"HKLM\Software\Wow6432Node\Microsoft\VisualStudio\%s" % version,
+            r"HKLM\Software\Microsoft\VCExpress\%s" % version,
+            r"HKLM\Software\Wow6432Node\Microsoft\VCExpress\%s" % version,
+        ]
+        for index in range(len(keys)):
+            path = _RegistryGetValue(keys[index], "InstallDir")
+            if not path:
+                continue
+            path = _ConvertToCygpath(path)
+            # Check for full.
+            full_path = os.path.join(path, "devenv.exe")
+            express_path = os.path.join(path, "*express.exe")
+            if not force_express and os.path.exists(full_path):
+                # Add this one.
+                versions.append(
+                    _CreateVersion(
+                        version_to_year[version], os.path.join(path, "..", "..")
+                    )
+                )
+            # Check for express.
+            elif glob.glob(express_path):
+                # Add this one.
+                versions.append(
+                    _CreateVersion(
+                        version_to_year[version] + "e", os.path.join(path, "..", "..")
+                    )
+                )
+
+        # The old method above does not work when only SDK is installed.
+        keys = [
+            r"HKLM\Software\Microsoft\VisualStudio\SxS\VC7",
+            r"HKLM\Software\Wow6432Node\Microsoft\VisualStudio\SxS\VC7",
+            r"HKLM\Software\Microsoft\VisualStudio\SxS\VS7",
+            r"HKLM\Software\Wow6432Node\Microsoft\VisualStudio\SxS\VS7",
+        ]
+        for index in range(len(keys)):
+            path = _RegistryGetValue(keys[index], version)
+            if not path:
+                continue
+            path = _ConvertToCygpath(path)
+            if version == "15.0":
+                if os.path.exists(path):
+                    versions.append(_CreateVersion("2017", path))
+            elif version != "14.0":  # There is no Express edition for 2015.
+                versions.append(
+                    _CreateVersion(
+                        version_to_year[version] + "e",
+                        os.path.join(path, ".."),
+                        sdk_based=True,
+                    )
+                )
+
+    return versions
+
+
+def SelectVisualStudioVersion(version="auto", allow_fallback=True):
+    """Select which version of Visual Studio projects to generate.
+
+  Arguments:
+    version: Hook to allow caller to force a particular version (vs auto).
+  Returns:
+    An object representing a visual studio project format version.
+  """
+    # In auto mode, check environment variable for override.
+    if version == "auto":
+        version = os.environ.get("GYP_MSVS_VERSION", "auto")
+    version_map = {
+        "auto": ("17.0", "16.0", "15.0", "14.0", "12.0", "10.0", "9.0", "8.0", "11.0"),
+        "2005": ("8.0",),
+        "2005e": ("8.0",),
+        "2008": ("9.0",),
+        "2008e": ("9.0",),
+        "2010": ("10.0",),
+        "2010e": ("10.0",),
+        "2012": ("11.0",),
+        "2012e": ("11.0",),
+        "2013": ("12.0",),
+        "2013e": ("12.0",),
+        "2015": ("14.0",),
+        "2017": ("15.0",),
+        "2019": ("16.0",),
+        "2022": ("17.0",),
+    }
+    override_path = os.environ.get("GYP_MSVS_OVERRIDE_PATH")
+    if override_path:
+        msvs_version = os.environ.get("GYP_MSVS_VERSION")
+        if not msvs_version:
+            raise ValueError(
+                "GYP_MSVS_OVERRIDE_PATH requires GYP_MSVS_VERSION to be "
+                "set to a particular version (e.g. 2010e)."
+            )
+        return _CreateVersion(msvs_version, override_path, sdk_based=True)
+    version = str(version)
+    versions = _DetectVisualStudioVersions(version_map[version], "e" in version)
+    if not versions:
+        if not allow_fallback:
+            raise ValueError("Could not locate Visual Studio installation.")
+        if version == "auto":
+            # Default to 2005 if we couldn't find anything
+            return _CreateVersion("2005", None)
+        else:
+            return _CreateVersion(version, None)
+    return versions[0]
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/__init__.py b/server/node_modules/node-gyp/gyp/pylib/gyp/__init__.py
new file mode 100755
index 0000000..6790ef9
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/__init__.py
@@ -0,0 +1,666 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+import copy
+import gyp.input
+import argparse
+import os.path
+import re
+import shlex
+import sys
+import traceback
+from gyp.common import GypError
+
+# Default debug modes for GYP
+debug = {}
+
+# List of "official" debug modes, but you can use anything you like.
+DEBUG_GENERAL = "general"
+DEBUG_VARIABLES = "variables"
+DEBUG_INCLUDES = "includes"
+
+
+def DebugOutput(mode, message, *args):
+    if "all" in gyp.debug or mode in gyp.debug:
+        ctx = ("unknown", 0, "unknown")
+        try:
+            f = traceback.extract_stack(limit=2)
+            if f:
+                ctx = f[0][:3]
+        except Exception:
+            pass
+        if args:
+            message %= args
+        print(
+            "%s:%s:%d:%s %s"
+            % (mode.upper(), os.path.basename(ctx[0]), ctx[1], ctx[2], message)
+        )
+
+
+def FindBuildFiles():
+    extension = ".gyp"
+    files = os.listdir(os.getcwd())
+    build_files = []
+    for file in files:
+        if file.endswith(extension):
+            build_files.append(file)
+    return build_files
+
+
+def Load(
+    build_files,
+    format,
+    default_variables={},
+    includes=[],
+    depth=".",
+    params=None,
+    check=False,
+    circular_check=True,
+):
+    """
+  Loads one or more specified build files.
+  default_variables and includes will be copied before use.
+  Returns the generator for the specified format and the
+  data returned by loading the specified build files.
+  """
+    if params is None:
+        params = {}
+
+    if "-" in format:
+        format, params["flavor"] = format.split("-", 1)
+
+    default_variables = copy.copy(default_variables)
+
+    # Default variables provided by this program and its modules should be
+    # named WITH_CAPITAL_LETTERS to provide a distinct "best practice" namespace,
+    # avoiding collisions with user and automatic variables.
+    default_variables["GENERATOR"] = format
+    default_variables["GENERATOR_FLAVOR"] = params.get("flavor", "")
+
+    # Format can be a custom python file, or by default the name of a module
+    # within gyp.generator.
+    if format.endswith(".py"):
+        generator_name = os.path.splitext(format)[0]
+        path, generator_name = os.path.split(generator_name)
+
+        # Make sure the path to the custom generator is in sys.path
+        # Don't worry about removing it once we are done.  Keeping the path
+        # to each generator that is used in sys.path is likely harmless and
+        # arguably a good idea.
+        path = os.path.abspath(path)
+        if path not in sys.path:
+            sys.path.insert(0, path)
+    else:
+        generator_name = "gyp.generator." + format
+
+    # These parameters are passed in order (as opposed to by key)
+    # because ActivePython cannot handle key parameters to __import__.
+    generator = __import__(generator_name, globals(), locals(), generator_name)
+    for (key, val) in generator.generator_default_variables.items():
+        default_variables.setdefault(key, val)
+
+    # Give the generator the opportunity to set additional variables based on
+    # the params it will receive in the output phase.
+    if getattr(generator, "CalculateVariables", None):
+        generator.CalculateVariables(default_variables, params)
+
+    # Give the generator the opportunity to set generator_input_info based on
+    # the params it will receive in the output phase.
+    if getattr(generator, "CalculateGeneratorInputInfo", None):
+        generator.CalculateGeneratorInputInfo(params)
+
+    # Fetch the generator specific info that gets fed to input, we use getattr
+    # so we can default things and the generators only have to provide what
+    # they need.
+    generator_input_info = {
+        "non_configuration_keys": getattr(
+            generator, "generator_additional_non_configuration_keys", []
+        ),
+        "path_sections": getattr(generator, "generator_additional_path_sections", []),
+        "extra_sources_for_rules": getattr(
+            generator, "generator_extra_sources_for_rules", []
+        ),
+        "generator_supports_multiple_toolsets": getattr(
+            generator, "generator_supports_multiple_toolsets", False
+        ),
+        "generator_wants_static_library_dependencies_adjusted": getattr(
+            generator, "generator_wants_static_library_dependencies_adjusted", True
+        ),
+        "generator_wants_sorted_dependencies": getattr(
+            generator, "generator_wants_sorted_dependencies", False
+        ),
+        "generator_filelist_paths": getattr(
+            generator, "generator_filelist_paths", None
+        ),
+    }
+
+    # Process the input specific to this generator.
+    result = gyp.input.Load(
+        build_files,
+        default_variables,
+        includes[:],
+        depth,
+        generator_input_info,
+        check,
+        circular_check,
+        params["parallel"],
+        params["root_targets"],
+    )
+    return [generator] + result
+
+
+def NameValueListToDict(name_value_list):
+    """
+  Takes an array of strings of the form 'NAME=VALUE' and creates a dictionary
+  of the pairs.  If a string is simply NAME, then the value in the dictionary
+  is set to True.  If VALUE can be converted to an integer, it is.
+  """
+    result = {}
+    for item in name_value_list:
+        tokens = item.split("=", 1)
+        if len(tokens) == 2:
+            # If we can make it an int, use that, otherwise, use the string.
+            try:
+                token_value = int(tokens[1])
+            except ValueError:
+                token_value = tokens[1]
+            # Set the variable to the supplied value.
+            result[tokens[0]] = token_value
+        else:
+            # No value supplied, treat it as a boolean and set it.
+            result[tokens[0]] = True
+    return result
+
+
+def ShlexEnv(env_name):
+    flags = os.environ.get(env_name, [])
+    if flags:
+        flags = shlex.split(flags)
+    return flags
+
+
+def FormatOpt(opt, value):
+    if opt.startswith("--"):
+        return f"{opt}={value}"
+    return opt + value
+
+
+def RegenerateAppendFlag(flag, values, predicate, env_name, options):
+    """Regenerate a list of command line flags, for an option of action='append'.
+
+  The |env_name|, if given, is checked in the environment and used to generate
+  an initial list of options, then the options that were specified on the
+  command line (given in |values|) are appended.  This matches the handling of
+  environment variables and command line flags where command line flags override
+  the environment, while not requiring the environment to be set when the flags
+  are used again.
+  """
+    flags = []
+    if options.use_environment and env_name:
+        for flag_value in ShlexEnv(env_name):
+            value = FormatOpt(flag, predicate(flag_value))
+            if value in flags:
+                flags.remove(value)
+            flags.append(value)
+    if values:
+        for flag_value in values:
+            flags.append(FormatOpt(flag, predicate(flag_value)))
+    return flags
+
+
+def RegenerateFlags(options):
+    """Given a parsed options object, and taking the environment variables into
+  account, returns a list of flags that should regenerate an equivalent options
+  object (even in the absence of the environment variables.)
+
+  Any path options will be normalized relative to depth.
+
+  The format flag is not included, as it is assumed the calling generator will
+  set that as appropriate.
+  """
+
+    def FixPath(path):
+        path = gyp.common.FixIfRelativePath(path, options.depth)
+        if not path:
+            return os.path.curdir
+        return path
+
+    def Noop(value):
+        return value
+
+    # We always want to ignore the environment when regenerating, to avoid
+    # duplicate or changed flags in the environment at the time of regeneration.
+    flags = ["--ignore-environment"]
+    for name, metadata in options._regeneration_metadata.items():
+        opt = metadata["opt"]
+        value = getattr(options, name)
+        value_predicate = metadata["type"] == "path" and FixPath or Noop
+        action = metadata["action"]
+        env_name = metadata["env_name"]
+        if action == "append":
+            flags.extend(
+                RegenerateAppendFlag(opt, value, value_predicate, env_name, options)
+            )
+        elif action in ("store", None):  # None is a synonym for 'store'.
+            if value:
+                flags.append(FormatOpt(opt, value_predicate(value)))
+            elif options.use_environment and env_name and os.environ.get(env_name):
+                flags.append(FormatOpt(opt, value_predicate(os.environ.get(env_name))))
+        elif action in ("store_true", "store_false"):
+            if (action == "store_true" and value) or (
+                action == "store_false" and not value
+            ):
+                flags.append(opt)
+            elif options.use_environment and env_name:
+                print(
+                    "Warning: environment regeneration unimplemented "
+                    "for %s flag %r env_name %r" % (action, opt, env_name),
+                    file=sys.stderr,
+                )
+        else:
+            print(
+                "Warning: regeneration unimplemented for action %r "
+                "flag %r" % (action, opt),
+                file=sys.stderr,
+            )
+
+    return flags
+
+
+class RegeneratableOptionParser(argparse.ArgumentParser):
+    def __init__(self, usage):
+        self.__regeneratable_options = {}
+        argparse.ArgumentParser.__init__(self, usage=usage)
+
+    def add_argument(self, *args, **kw):
+        """Add an option to the parser.
+
+    This accepts the same arguments as ArgumentParser.add_argument, plus the
+    following:
+      regenerate: can be set to False to prevent this option from being included
+                  in regeneration.
+      env_name: name of environment variable that additional values for this
+                option come from.
+      type: adds type='path', to tell the regenerator that the values of
+            this option need to be made relative to options.depth
+    """
+        env_name = kw.pop("env_name", None)
+        if "dest" in kw and kw.pop("regenerate", True):
+            dest = kw["dest"]
+
+            # The path type is needed for regenerating, for optparse we can just treat
+            # it as a string.
+            type = kw.get("type")
+            if type == "path":
+                kw["type"] = str
+
+            self.__regeneratable_options[dest] = {
+                "action": kw.get("action"),
+                "type": type,
+                "env_name": env_name,
+                "opt": args[0],
+            }
+
+        argparse.ArgumentParser.add_argument(self, *args, **kw)
+
+    def parse_args(self, *args):
+        values, args = argparse.ArgumentParser.parse_known_args(self, *args)
+        values._regeneration_metadata = self.__regeneratable_options
+        return values, args
+
+
+def gyp_main(args):
+    my_name = os.path.basename(sys.argv[0])
+    usage = "usage: %(prog)s [options ...] [build_file ...]"
+
+    parser = RegeneratableOptionParser(usage=usage.replace("%s", "%(prog)s"))
+    parser.add_argument(
+        "--build",
+        dest="configs",
+        action="append",
+        help="configuration for build after project generation",
+    )
+    parser.add_argument(
+        "--check", dest="check", action="store_true", help="check format of gyp files"
+    )
+    parser.add_argument(
+        "--config-dir",
+        dest="config_dir",
+        action="store",
+        env_name="GYP_CONFIG_DIR",
+        default=None,
+        help="The location for configuration files like " "include.gypi.",
+    )
+    parser.add_argument(
+        "-d",
+        "--debug",
+        dest="debug",
+        metavar="DEBUGMODE",
+        action="append",
+        default=[],
+        help="turn on a debugging "
+        'mode for debugging GYP.  Supported modes are "variables", '
+        '"includes" and "general" or "all" for all of them.',
+    )
+    parser.add_argument(
+        "-D",
+        dest="defines",
+        action="append",
+        metavar="VAR=VAL",
+        env_name="GYP_DEFINES",
+        help="sets variable VAR to value VAL",
+    )
+    parser.add_argument(
+        "--depth",
+        dest="depth",
+        metavar="PATH",
+        type="path",
+        help="set DEPTH gyp variable to a relative path to PATH",
+    )
+    parser.add_argument(
+        "-f",
+        "--format",
+        dest="formats",
+        action="append",
+        env_name="GYP_GENERATORS",
+        regenerate=False,
+        help="output formats to generate",
+    )
+    parser.add_argument(
+        "-G",
+        dest="generator_flags",
+        action="append",
+        default=[],
+        metavar="FLAG=VAL",
+        env_name="GYP_GENERATOR_FLAGS",
+        help="sets generator flag FLAG to VAL",
+    )
+    parser.add_argument(
+        "--generator-output",
+        dest="generator_output",
+        action="store",
+        default=None,
+        metavar="DIR",
+        type="path",
+        env_name="GYP_GENERATOR_OUTPUT",
+        help="puts generated build files under DIR",
+    )
+    parser.add_argument(
+        "--ignore-environment",
+        dest="use_environment",
+        action="store_false",
+        default=True,
+        regenerate=False,
+        help="do not read options from environment variables",
+    )
+    parser.add_argument(
+        "-I",
+        "--include",
+        dest="includes",
+        action="append",
+        metavar="INCLUDE",
+        type="path",
+        help="files to include in all loaded .gyp files",
+    )
+    # --no-circular-check disables the check for circular relationships between
+    # .gyp files.  These relationships should not exist, but they've only been
+    # observed to be harmful with the Xcode generator.  Chromium's .gyp files
+    # currently have some circular relationships on non-Mac platforms, so this
+    # option allows the strict behavior to be used on Macs and the lenient
+    # behavior to be used elsewhere.
+    # TODO(mark): Remove this option when http://crbug.com/35878 is fixed.
+    parser.add_argument(
+        "--no-circular-check",
+        dest="circular_check",
+        action="store_false",
+        default=True,
+        regenerate=False,
+        help="don't check for circular relationships between files",
+    )
+    parser.add_argument(
+        "--no-parallel",
+        action="store_true",
+        default=False,
+        help="Disable multiprocessing",
+    )
+    parser.add_argument(
+        "-S",
+        "--suffix",
+        dest="suffix",
+        default="",
+        help="suffix to add to generated files",
+    )
+    parser.add_argument(
+        "--toplevel-dir",
+        dest="toplevel_dir",
+        action="store",
+        default=None,
+        metavar="DIR",
+        type="path",
+        help="directory to use as the root of the source tree",
+    )
+    parser.add_argument(
+        "-R",
+        "--root-target",
+        dest="root_targets",
+        action="append",
+        metavar="TARGET",
+        help="include only TARGET and its deep dependencies",
+    )
+
+    options, build_files_arg = parser.parse_args(args)
+    build_files = build_files_arg
+
+    # Set up the configuration directory (defaults to ~/.gyp)
+    if not options.config_dir:
+        home = None
+        home_dot_gyp = None
+        if options.use_environment:
+            home_dot_gyp = os.environ.get("GYP_CONFIG_DIR", None)
+            if home_dot_gyp:
+                home_dot_gyp = os.path.expanduser(home_dot_gyp)
+
+        if not home_dot_gyp:
+            home_vars = ["HOME"]
+            if sys.platform in ("cygwin", "win32"):
+                home_vars.append("USERPROFILE")
+            for home_var in home_vars:
+                home = os.getenv(home_var)
+                if home:
+                    home_dot_gyp = os.path.join(home, ".gyp")
+                    if not os.path.exists(home_dot_gyp):
+                        home_dot_gyp = None
+                    else:
+                        break
+    else:
+        home_dot_gyp = os.path.expanduser(options.config_dir)
+
+    if home_dot_gyp and not os.path.exists(home_dot_gyp):
+        home_dot_gyp = None
+
+    if not options.formats:
+        # If no format was given on the command line, then check the env variable.
+        generate_formats = []
+        if options.use_environment:
+            generate_formats = os.environ.get("GYP_GENERATORS", [])
+        if generate_formats:
+            generate_formats = re.split(r"[\s,]", generate_formats)
+        if generate_formats:
+            options.formats = generate_formats
+        else:
+            # Nothing in the variable, default based on platform.
+            if sys.platform == "darwin":
+                options.formats = ["xcode"]
+            elif sys.platform in ("win32", "cygwin"):
+                options.formats = ["msvs"]
+            else:
+                options.formats = ["make"]
+
+    if not options.generator_output and options.use_environment:
+        g_o = os.environ.get("GYP_GENERATOR_OUTPUT")
+        if g_o:
+            options.generator_output = g_o
+
+    options.parallel = not options.no_parallel
+
+    for mode in options.debug:
+        gyp.debug[mode] = 1
+
+    # Do an extra check to avoid work when we're not debugging.
+    if DEBUG_GENERAL in gyp.debug:
+        DebugOutput(DEBUG_GENERAL, "running with these options:")
+        for option, value in sorted(options.__dict__.items()):
+            if option[0] == "_":
+                continue
+            if isinstance(value, str):
+                DebugOutput(DEBUG_GENERAL, "  %s: '%s'", option, value)
+            else:
+                DebugOutput(DEBUG_GENERAL, "  %s: %s", option, value)
+
+    if not build_files:
+        build_files = FindBuildFiles()
+    if not build_files:
+        raise GypError((usage + "\n\n%s: error: no build_file") % (my_name, my_name))
+
+    # TODO(mark): Chromium-specific hack!
+    # For Chromium, the gyp "depth" variable should always be a relative path
+    # to Chromium's top-level "src" directory.  If no depth variable was set
+    # on the command line, try to find a "src" directory by looking at the
+    # absolute path to each build file's directory.  The first "src" component
+    # found will be treated as though it were the path used for --depth.
+    if not options.depth:
+        for build_file in build_files:
+            build_file_dir = os.path.abspath(os.path.dirname(build_file))
+            build_file_dir_components = build_file_dir.split(os.path.sep)
+            components_len = len(build_file_dir_components)
+            for index in range(components_len - 1, -1, -1):
+                if build_file_dir_components[index] == "src":
+                    options.depth = os.path.sep.join(build_file_dir_components)
+                    break
+                del build_file_dir_components[index]
+
+            # If the inner loop found something, break without advancing to another
+            # build file.
+            if options.depth:
+                break
+
+        if not options.depth:
+            raise GypError(
+                "Could not automatically locate src directory.  This is"
+                "a temporary Chromium feature that will be removed.  Use"
+                "--depth as a workaround."
+            )
+
+    # If toplevel-dir is not set, we assume that depth is the root of our source
+    # tree.
+    if not options.toplevel_dir:
+        options.toplevel_dir = options.depth
+
+    # -D on the command line sets variable defaults - D isn't just for define,
+    # it's for default.  Perhaps there should be a way to force (-F?) a
+    # variable's value so that it can't be overridden by anything else.
+    cmdline_default_variables = {}
+    defines = []
+    if options.use_environment:
+        defines += ShlexEnv("GYP_DEFINES")
+    if options.defines:
+        defines += options.defines
+    cmdline_default_variables = NameValueListToDict(defines)
+    if DEBUG_GENERAL in gyp.debug:
+        DebugOutput(
+            DEBUG_GENERAL, "cmdline_default_variables: %s", cmdline_default_variables
+        )
+
+    # Set up includes.
+    includes = []
+
+    # If ~/.gyp/include.gypi exists, it'll be forcibly included into every
+    # .gyp file that's loaded, before anything else is included.
+    if home_dot_gyp:
+        default_include = os.path.join(home_dot_gyp, "include.gypi")
+        if os.path.exists(default_include):
+            print("Using overrides found in " + default_include)
+            includes.append(default_include)
+
+    # Command-line --include files come after the default include.
+    if options.includes:
+        includes.extend(options.includes)
+
+    # Generator flags should be prefixed with the target generator since they
+    # are global across all generator runs.
+    gen_flags = []
+    if options.use_environment:
+        gen_flags += ShlexEnv("GYP_GENERATOR_FLAGS")
+    if options.generator_flags:
+        gen_flags += options.generator_flags
+    generator_flags = NameValueListToDict(gen_flags)
+    if DEBUG_GENERAL in gyp.debug.keys():
+        DebugOutput(DEBUG_GENERAL, "generator_flags: %s", generator_flags)
+
+    # Generate all requested formats (use a set in case we got one format request
+    # twice)
+    for format in set(options.formats):
+        params = {
+            "options": options,
+            "build_files": build_files,
+            "generator_flags": generator_flags,
+            "cwd": os.getcwd(),
+            "build_files_arg": build_files_arg,
+            "gyp_binary": sys.argv[0],
+            "home_dot_gyp": home_dot_gyp,
+            "parallel": options.parallel,
+            "root_targets": options.root_targets,
+            "target_arch": cmdline_default_variables.get("target_arch", ""),
+        }
+
+        # Start with the default variables from the command line.
+        [generator, flat_list, targets, data] = Load(
+            build_files,
+            format,
+            cmdline_default_variables,
+            includes,
+            options.depth,
+            params,
+            options.check,
+            options.circular_check,
+        )
+
+        # TODO(mark): Pass |data| for now because the generator needs a list of
+        # build files that came in.  In the future, maybe it should just accept
+        # a list, and not the whole data dict.
+        # NOTE: flat_list is the flattened dependency graph specifying the order
+        # that targets may be built.  Build systems that operate serially or that
+        # need to have dependencies defined before dependents reference them should
+        # generate targets in the order specified in flat_list.
+        generator.GenerateOutput(flat_list, targets, data, params)
+
+        if options.configs:
+            valid_configs = targets[flat_list[0]]["configurations"]
+            for conf in options.configs:
+                if conf not in valid_configs:
+                    raise GypError("Invalid config specified via --build: %s" % conf)
+            generator.PerformBuild(data, options.configs, params)
+
+    # Done
+    return 0
+
+
+def main(args):
+    try:
+        return gyp_main(args)
+    except GypError as e:
+        sys.stderr.write("gyp: %s\n" % e)
+        return 1
+
+
+# NOTE: setuptools generated console_scripts calls function with no arguments
+def script_main():
+    return main(sys.argv[1:])
+
+
+if __name__ == "__main__":
+    sys.exit(script_main())
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/common.py b/server/node_modules/node-gyp/gyp/pylib/gyp/common.py
new file mode 100644
index 0000000..9213fcc
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/common.py
@@ -0,0 +1,654 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import errno
+import filecmp
+import os.path
+import re
+import tempfile
+import sys
+import subprocess
+
+from collections.abc import MutableSet
+
+
+# A minimal memoizing decorator. It'll blow up if the args aren't immutable,
+# among other "problems".
+class memoize:
+    def __init__(self, func):
+        self.func = func
+        self.cache = {}
+
+    def __call__(self, *args):
+        try:
+            return self.cache[args]
+        except KeyError:
+            result = self.func(*args)
+            self.cache[args] = result
+            return result
+
+
+class GypError(Exception):
+    """Error class representing an error, which is to be presented
+  to the user.  The main entry point will catch and display this.
+  """
+
+    pass
+
+
+def ExceptionAppend(e, msg):
+    """Append a message to the given exception's message."""
+    if not e.args:
+        e.args = (msg,)
+    elif len(e.args) == 1:
+        e.args = (str(e.args[0]) + " " + msg,)
+    else:
+        e.args = (str(e.args[0]) + " " + msg,) + e.args[1:]
+
+
+def FindQualifiedTargets(target, qualified_list):
+    """
+  Given a list of qualified targets, return the qualified targets for the
+  specified |target|.
+  """
+    return [t for t in qualified_list if ParseQualifiedTarget(t)[1] == target]
+
+
+def ParseQualifiedTarget(target):
+    # Splits a qualified target into a build file, target name and toolset.
+
+    # NOTE: rsplit is used to disambiguate the Windows drive letter separator.
+    target_split = target.rsplit(":", 1)
+    if len(target_split) == 2:
+        [build_file, target] = target_split
+    else:
+        build_file = None
+
+    target_split = target.rsplit("#", 1)
+    if len(target_split) == 2:
+        [target, toolset] = target_split
+    else:
+        toolset = None
+
+    return [build_file, target, toolset]
+
+
+def ResolveTarget(build_file, target, toolset):
+    # This function resolves a target into a canonical form:
+    # - a fully defined build file, either absolute or relative to the current
+    # directory
+    # - a target name
+    # - a toolset
+    #
+    # build_file is the file relative to which 'target' is defined.
+    # target is the qualified target.
+    # toolset is the default toolset for that target.
+    [parsed_build_file, target, parsed_toolset] = ParseQualifiedTarget(target)
+
+    if parsed_build_file:
+        if build_file:
+            # If a relative path, parsed_build_file is relative to the directory
+            # containing build_file.  If build_file is not in the current directory,
+            # parsed_build_file is not a usable path as-is.  Resolve it by
+            # interpreting it as relative to build_file.  If parsed_build_file is
+            # absolute, it is usable as a path regardless of the current directory,
+            # and os.path.join will return it as-is.
+            build_file = os.path.normpath(
+                os.path.join(os.path.dirname(build_file), parsed_build_file)
+            )
+            # Further (to handle cases like ../cwd), make it relative to cwd)
+            if not os.path.isabs(build_file):
+                build_file = RelativePath(build_file, ".")
+        else:
+            build_file = parsed_build_file
+
+    if parsed_toolset:
+        toolset = parsed_toolset
+
+    return [build_file, target, toolset]
+
+
+def BuildFile(fully_qualified_target):
+    # Extracts the build file from the fully qualified target.
+    return ParseQualifiedTarget(fully_qualified_target)[0]
+
+
+def GetEnvironFallback(var_list, default):
+    """Look up a key in the environment, with fallback to secondary keys
+  and finally falling back to a default value."""
+    for var in var_list:
+        if var in os.environ:
+            return os.environ[var]
+    return default
+
+
+def QualifiedTarget(build_file, target, toolset):
+    # "Qualified" means the file that a target was defined in and the target
+    # name, separated by a colon, suffixed by a # and the toolset name:
+    # /path/to/file.gyp:target_name#toolset
+    fully_qualified = build_file + ":" + target
+    if toolset:
+        fully_qualified = fully_qualified + "#" + toolset
+    return fully_qualified
+
+
+@memoize
+def RelativePath(path, relative_to, follow_path_symlink=True):
+    # Assuming both |path| and |relative_to| are relative to the current
+    # directory, returns a relative path that identifies path relative to
+    # relative_to.
+    # If |follow_symlink_path| is true (default) and |path| is a symlink, then
+    # this method returns a path to the real file represented by |path|. If it is
+    # false, this method returns a path to the symlink. If |path| is not a
+    # symlink, this option has no effect.
+
+    # Convert to normalized (and therefore absolute paths).
+    if follow_path_symlink:
+        path = os.path.realpath(path)
+    else:
+        path = os.path.abspath(path)
+    relative_to = os.path.realpath(relative_to)
+
+    # On Windows, we can't create a relative path to a different drive, so just
+    # use the absolute path.
+    if sys.platform == "win32":
+        if (
+            os.path.splitdrive(path)[0].lower()
+            != os.path.splitdrive(relative_to)[0].lower()
+        ):
+            return path
+
+    # Split the paths into components.
+    path_split = path.split(os.path.sep)
+    relative_to_split = relative_to.split(os.path.sep)
+
+    # Determine how much of the prefix the two paths share.
+    prefix_len = len(os.path.commonprefix([path_split, relative_to_split]))
+
+    # Put enough ".." components to back up out of relative_to to the common
+    # prefix, and then append the part of path_split after the common prefix.
+    relative_split = [os.path.pardir] * (
+        len(relative_to_split) - prefix_len
+    ) + path_split[prefix_len:]
+
+    if len(relative_split) == 0:
+        # The paths were the same.
+        return ""
+
+    # Turn it back into a string and we're done.
+    return os.path.join(*relative_split)
+
+
+@memoize
+def InvertRelativePath(path, toplevel_dir=None):
+    """Given a path like foo/bar that is relative to toplevel_dir, return
+  the inverse relative path back to the toplevel_dir.
+
+  E.g. os.path.normpath(os.path.join(path, InvertRelativePath(path)))
+  should always produce the empty string, unless the path contains symlinks.
+  """
+    if not path:
+        return path
+    toplevel_dir = "." if toplevel_dir is None else toplevel_dir
+    return RelativePath(toplevel_dir, os.path.join(toplevel_dir, path))
+
+
+def FixIfRelativePath(path, relative_to):
+    # Like RelativePath but returns |path| unchanged if it is absolute.
+    if os.path.isabs(path):
+        return path
+    return RelativePath(path, relative_to)
+
+
+def UnrelativePath(path, relative_to):
+    # Assuming that |relative_to| is relative to the current directory, and |path|
+    # is a path relative to the dirname of |relative_to|, returns a path that
+    # identifies |path| relative to the current directory.
+    rel_dir = os.path.dirname(relative_to)
+    return os.path.normpath(os.path.join(rel_dir, path))
+
+
+# re objects used by EncodePOSIXShellArgument.  See IEEE 1003.1 XCU.2.2 at
+# http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_02
+# and the documentation for various shells.
+
+# _quote is a pattern that should match any argument that needs to be quoted
+# with double-quotes by EncodePOSIXShellArgument.  It matches the following
+# characters appearing anywhere in an argument:
+#   \t, \n, space  parameter separators
+#   #              comments
+#   $              expansions (quoted to always expand within one argument)
+#   %              called out by IEEE 1003.1 XCU.2.2
+#   &              job control
+#   '              quoting
+#   (, )           subshell execution
+#   *, ?, [        pathname expansion
+#   ;              command delimiter
+#   <, >, |        redirection
+#   =              assignment
+#   {, }           brace expansion (bash)
+#   ~              tilde expansion
+# It also matches the empty string, because "" (or '') is the only way to
+# represent an empty string literal argument to a POSIX shell.
+#
+# This does not match the characters in _escape, because those need to be
+# backslash-escaped regardless of whether they appear in a double-quoted
+# string.
+_quote = re.compile("[\t\n #$%&'()*;<=>?[{|}~]|^$")
+
+# _escape is a pattern that should match any character that needs to be
+# escaped with a backslash, whether or not the argument matched the _quote
+# pattern.  _escape is used with re.sub to backslash anything in _escape's
+# first match group, hence the (parentheses) in the regular expression.
+#
+# _escape matches the following characters appearing anywhere in an argument:
+#   "  to prevent POSIX shells from interpreting this character for quoting
+#   \  to prevent POSIX shells from interpreting this character for escaping
+#   `  to prevent POSIX shells from interpreting this character for command
+#      substitution
+# Missing from this list is $, because the desired behavior of
+# EncodePOSIXShellArgument is to permit parameter (variable) expansion.
+#
+# Also missing from this list is !, which bash will interpret as the history
+# expansion character when history is enabled.  bash does not enable history
+# by default in non-interactive shells, so this is not thought to be a problem.
+# ! was omitted from this list because bash interprets "\!" as a literal string
+# including the backslash character (avoiding history expansion but retaining
+# the backslash), which would not be correct for argument encoding.  Handling
+# this case properly would also be problematic because bash allows the history
+# character to be changed with the histchars shell variable.  Fortunately,
+# as history is not enabled in non-interactive shells and
+# EncodePOSIXShellArgument is only expected to encode for non-interactive
+# shells, there is no room for error here by ignoring !.
+_escape = re.compile(r'(["\\`])')
+
+
+def EncodePOSIXShellArgument(argument):
+    """Encodes |argument| suitably for consumption by POSIX shells.
+
+  argument may be quoted and escaped as necessary to ensure that POSIX shells
+  treat the returned value as a literal representing the argument passed to
+  this function.  Parameter (variable) expansions beginning with $ are allowed
+  to remain intact without escaping the $, to allow the argument to contain
+  references to variables to be expanded by the shell.
+  """
+
+    if not isinstance(argument, str):
+        argument = str(argument)
+
+    if _quote.search(argument):
+        quote = '"'
+    else:
+        quote = ""
+
+    encoded = quote + re.sub(_escape, r"\\\1", argument) + quote
+
+    return encoded
+
+
+def EncodePOSIXShellList(list):
+    """Encodes |list| suitably for consumption by POSIX shells.
+
+  Returns EncodePOSIXShellArgument for each item in list, and joins them
+  together using the space character as an argument separator.
+  """
+
+    encoded_arguments = []
+    for argument in list:
+        encoded_arguments.append(EncodePOSIXShellArgument(argument))
+    return " ".join(encoded_arguments)
+
+
+def DeepDependencyTargets(target_dicts, roots):
+    """Returns the recursive list of target dependencies."""
+    dependencies = set()
+    pending = set(roots)
+    while pending:
+        # Pluck out one.
+        r = pending.pop()
+        # Skip if visited already.
+        if r in dependencies:
+            continue
+        # Add it.
+        dependencies.add(r)
+        # Add its children.
+        spec = target_dicts[r]
+        pending.update(set(spec.get("dependencies", [])))
+        pending.update(set(spec.get("dependencies_original", [])))
+    return list(dependencies - set(roots))
+
+
+def BuildFileTargets(target_list, build_file):
+    """From a target_list, returns the subset from the specified build_file.
+  """
+    return [p for p in target_list if BuildFile(p) == build_file]
+
+
+def AllTargets(target_list, target_dicts, build_file):
+    """Returns all targets (direct and dependencies) for the specified build_file.
+  """
+    bftargets = BuildFileTargets(target_list, build_file)
+    deptargets = DeepDependencyTargets(target_dicts, bftargets)
+    return bftargets + deptargets
+
+
+def WriteOnDiff(filename):
+    """Write to a file only if the new contents differ.
+
+  Arguments:
+    filename: name of the file to potentially write to.
+  Returns:
+    A file like object which will write to temporary file and only overwrite
+    the target if it differs (on close).
+  """
+
+    class Writer:
+        """Wrapper around file which only covers the target if it differs."""
+
+        def __init__(self):
+            # On Cygwin remove the "dir" argument
+            # `C:` prefixed paths are treated as relative,
+            # consequently ending up with current dir "/cygdrive/c/..."
+            # being prefixed to those, which was
+            # obviously a non-existent path,
+            # for example: "/cygdrive/c/<some folder>/C:\<my win style abs path>".
+            # For more details see:
+            # https://docs.python.org/2/library/tempfile.html#tempfile.mkstemp
+            base_temp_dir = "" if IsCygwin() else os.path.dirname(filename)
+            # Pick temporary file.
+            tmp_fd, self.tmp_path = tempfile.mkstemp(
+                suffix=".tmp",
+                prefix=os.path.split(filename)[1] + ".gyp.",
+                dir=base_temp_dir,
+            )
+            try:
+                self.tmp_file = os.fdopen(tmp_fd, "wb")
+            except Exception:
+                # Don't leave turds behind.
+                os.unlink(self.tmp_path)
+                raise
+
+        def __getattr__(self, attrname):
+            # Delegate everything else to self.tmp_file
+            return getattr(self.tmp_file, attrname)
+
+        def close(self):
+            try:
+                # Close tmp file.
+                self.tmp_file.close()
+                # Determine if different.
+                same = False
+                try:
+                    same = filecmp.cmp(self.tmp_path, filename, False)
+                except OSError as e:
+                    if e.errno != errno.ENOENT:
+                        raise
+
+                if same:
+                    # The new file is identical to the old one, just get rid of the new
+                    # one.
+                    os.unlink(self.tmp_path)
+                else:
+                    # The new file is different from the old one,
+                    # or there is no old one.
+                    # Rename the new file to the permanent name.
+                    #
+                    # tempfile.mkstemp uses an overly restrictive mode, resulting in a
+                    # file that can only be read by the owner, regardless of the umask.
+                    # There's no reason to not respect the umask here,
+                    # which means that an extra hoop is required
+                    # to fetch it and reset the new file's mode.
+                    #
+                    # No way to get the umask without setting a new one?  Set a safe one
+                    # and then set it back to the old value.
+                    umask = os.umask(0o77)
+                    os.umask(umask)
+                    os.chmod(self.tmp_path, 0o666 & ~umask)
+                    if sys.platform == "win32" and os.path.exists(filename):
+                        # NOTE: on windows (but not cygwin) rename will not replace an
+                        # existing file, so it must be preceded with a remove.
+                        # Sadly there is no way to make the switch atomic.
+                        os.remove(filename)
+                    os.rename(self.tmp_path, filename)
+            except Exception:
+                # Don't leave turds behind.
+                os.unlink(self.tmp_path)
+                raise
+
+        def write(self, s):
+            self.tmp_file.write(s.encode("utf-8"))
+
+    return Writer()
+
+
+def EnsureDirExists(path):
+    """Make sure the directory for |path| exists."""
+    try:
+        os.makedirs(os.path.dirname(path))
+    except OSError:
+        pass
+
+
+def GetFlavor(params):
+    """Returns |params.flavor| if it's set, the system's default flavor else."""
+    flavors = {
+        "cygwin": "win",
+        "win32": "win",
+        "darwin": "mac",
+    }
+
+    if "flavor" in params:
+        return params["flavor"]
+    if sys.platform in flavors:
+        return flavors[sys.platform]
+    if sys.platform.startswith("sunos"):
+        return "solaris"
+    if sys.platform.startswith(("dragonfly", "freebsd")):
+        return "freebsd"
+    if sys.platform.startswith("openbsd"):
+        return "openbsd"
+    if sys.platform.startswith("netbsd"):
+        return "netbsd"
+    if sys.platform.startswith("aix"):
+        return "aix"
+    if sys.platform.startswith(("os390", "zos")):
+        return "zos"
+
+    return "linux"
+
+
+def CopyTool(flavor, out_path, generator_flags={}):
+    """Finds (flock|mac|win)_tool.gyp in the gyp directory and copies it
+  to |out_path|."""
+    # aix and solaris just need flock emulation. mac and win use more complicated
+    # support scripts.
+    prefix = {"aix": "flock", "solaris": "flock", "mac": "mac", "win": "win"}.get(
+        flavor, None
+    )
+    if not prefix:
+        return
+
+    # Slurp input file.
+    source_path = os.path.join(
+        os.path.dirname(os.path.abspath(__file__)), "%s_tool.py" % prefix
+    )
+    with open(source_path) as source_file:
+        source = source_file.readlines()
+
+    # Set custom header flags.
+    header = "# Generated by gyp. Do not edit.\n"
+    mac_toolchain_dir = generator_flags.get("mac_toolchain_dir", None)
+    if flavor == "mac" and mac_toolchain_dir:
+        header += "import os;\nos.environ['DEVELOPER_DIR']='%s'\n" % mac_toolchain_dir
+
+    # Add header and write it out.
+    tool_path = os.path.join(out_path, "gyp-%s-tool" % prefix)
+    with open(tool_path, "w") as tool_file:
+        tool_file.write("".join([source[0], header] + source[1:]))
+
+    # Make file executable.
+    os.chmod(tool_path, 0o755)
+
+
+# From Alex Martelli,
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52560
+# ASPN: Python Cookbook: Remove duplicates from a sequence
+# First comment, dated 2001/10/13.
+# (Also in the printed Python Cookbook.)
+
+
+def uniquer(seq, idfun=lambda x: x):
+    seen = {}
+    result = []
+    for item in seq:
+        marker = idfun(item)
+        if marker in seen:
+            continue
+        seen[marker] = 1
+        result.append(item)
+    return result
+
+
+# Based on http://code.activestate.com/recipes/576694/.
+class OrderedSet(MutableSet):
+    def __init__(self, iterable=None):
+        self.end = end = []
+        end += [None, end, end]  # sentinel node for doubly linked list
+        self.map = {}  # key --> [key, prev, next]
+        if iterable is not None:
+            self |= iterable
+
+    def __len__(self):
+        return len(self.map)
+
+    def __contains__(self, key):
+        return key in self.map
+
+    def add(self, key):
+        if key not in self.map:
+            end = self.end
+            curr = end[1]
+            curr[2] = end[1] = self.map[key] = [key, curr, end]
+
+    def discard(self, key):
+        if key in self.map:
+            key, prev_item, next_item = self.map.pop(key)
+            prev_item[2] = next_item
+            next_item[1] = prev_item
+
+    def __iter__(self):
+        end = self.end
+        curr = end[2]
+        while curr is not end:
+            yield curr[0]
+            curr = curr[2]
+
+    def __reversed__(self):
+        end = self.end
+        curr = end[1]
+        while curr is not end:
+            yield curr[0]
+            curr = curr[1]
+
+    # The second argument is an addition that causes a pylint warning.
+    def pop(self, last=True):  # pylint: disable=W0221
+        if not self:
+            raise KeyError("set is empty")
+        key = self.end[1][0] if last else self.end[2][0]
+        self.discard(key)
+        return key
+
+    def __repr__(self):
+        if not self:
+            return f"{self.__class__.__name__}()"
+        return f"{self.__class__.__name__}({list(self)!r})"
+
+    def __eq__(self, other):
+        if isinstance(other, OrderedSet):
+            return len(self) == len(other) and list(self) == list(other)
+        return set(self) == set(other)
+
+    # Extensions to the recipe.
+    def update(self, iterable):
+        for i in iterable:
+            if i not in self:
+                self.add(i)
+
+
+class CycleError(Exception):
+    """An exception raised when an unexpected cycle is detected."""
+
+    def __init__(self, nodes):
+        self.nodes = nodes
+
+    def __str__(self):
+        return "CycleError: cycle involving: " + str(self.nodes)
+
+
+def TopologicallySorted(graph, get_edges):
+    r"""Topologically sort based on a user provided edge definition.
+
+  Args:
+    graph: A list of node names.
+    get_edges: A function mapping from node name to a hashable collection
+               of node names which this node has outgoing edges to.
+  Returns:
+    A list containing all of the node in graph in topological order.
+    It is assumed that calling get_edges once for each node and caching is
+    cheaper than repeatedly calling get_edges.
+  Raises:
+    CycleError in the event of a cycle.
+  Example:
+    graph = {'a': '$(b) $(c)', 'b': 'hi', 'c': '$(b)'}
+    def GetEdges(node):
+      return re.findall(r'\$$([^))]$', graph[node])
+    print TopologicallySorted(graph.keys(), GetEdges)
+    ==>
+    ['a', 'c', b']
+  """
+    get_edges = memoize(get_edges)
+    visited = set()
+    visiting = set()
+    ordered_nodes = []
+
+    def Visit(node):
+        if node in visiting:
+            raise CycleError(visiting)
+        if node in visited:
+            return
+        visited.add(node)
+        visiting.add(node)
+        for neighbor in get_edges(node):
+            Visit(neighbor)
+        visiting.remove(node)
+        ordered_nodes.insert(0, node)
+
+    for node in sorted(graph):
+        Visit(node)
+    return ordered_nodes
+
+
+def CrossCompileRequested():
+    # TODO: figure out how to not build extra host objects in the
+    # non-cross-compile case when this is enabled, and enable unconditionally.
+    return (
+        os.environ.get("GYP_CROSSCOMPILE")
+        or os.environ.get("AR_host")
+        or os.environ.get("CC_host")
+        or os.environ.get("CXX_host")
+        or os.environ.get("AR_target")
+        or os.environ.get("CC_target")
+        or os.environ.get("CXX_target")
+    )
+
+
+def IsCygwin():
+    try:
+        out = subprocess.Popen(
+            "uname", stdout=subprocess.PIPE, stderr=subprocess.STDOUT
+        )
+        stdout = out.communicate()[0].decode("utf-8")
+        return "CYGWIN" in str(stdout)
+    except Exception:
+        return False
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/common_test.py b/server/node_modules/node-gyp/gyp/pylib/gyp/common_test.py
new file mode 100755
index 0000000..0534408
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/common_test.py
@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Unit tests for the common.py file."""
+
+import gyp.common
+import unittest
+import sys
+
+
+class TestTopologicallySorted(unittest.TestCase):
+    def test_Valid(self):
+        """Test that sorting works on a valid graph with one possible order."""
+        graph = {
+            "a": ["b", "c"],
+            "b": [],
+            "c": ["d"],
+            "d": ["b"],
+        }
+
+        def GetEdge(node):
+            return tuple(graph[node])
+
+        self.assertEqual(
+            gyp.common.TopologicallySorted(graph.keys(), GetEdge), ["a", "c", "d", "b"]
+        )
+
+    def test_Cycle(self):
+        """Test that an exception is thrown on a cyclic graph."""
+        graph = {
+            "a": ["b"],
+            "b": ["c"],
+            "c": ["d"],
+            "d": ["a"],
+        }
+
+        def GetEdge(node):
+            return tuple(graph[node])
+
+        self.assertRaises(
+            gyp.common.CycleError, gyp.common.TopologicallySorted, graph.keys(), GetEdge
+        )
+
+
+class TestGetFlavor(unittest.TestCase):
+    """Test that gyp.common.GetFlavor works as intended"""
+
+    original_platform = ""
+
+    def setUp(self):
+        self.original_platform = sys.platform
+
+    def tearDown(self):
+        sys.platform = self.original_platform
+
+    def assertFlavor(self, expected, argument, param):
+        sys.platform = argument
+        self.assertEqual(expected, gyp.common.GetFlavor(param))
+
+    def test_platform_default(self):
+        self.assertFlavor("freebsd", "freebsd9", {})
+        self.assertFlavor("freebsd", "freebsd10", {})
+        self.assertFlavor("openbsd", "openbsd5", {})
+        self.assertFlavor("solaris", "sunos5", {})
+        self.assertFlavor("solaris", "sunos", {})
+        self.assertFlavor("linux", "linux2", {})
+        self.assertFlavor("linux", "linux3", {})
+        self.assertFlavor("linux", "linux", {})
+
+    def test_param(self):
+        self.assertFlavor("foobar", "linux2", {"flavor": "foobar"})
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/easy_xml.py b/server/node_modules/node-gyp/gyp/pylib/gyp/easy_xml.py
new file mode 100644
index 0000000..bda1a47
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/easy_xml.py
@@ -0,0 +1,165 @@
+# Copyright (c) 2011 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import sys
+import re
+import os
+import locale
+from functools import reduce
+
+
+def XmlToString(content, encoding="utf-8", pretty=False):
+    """ Writes the XML content to disk, touching the file only if it has changed.
+
+  Visual Studio files have a lot of pre-defined structures.  This function makes
+  it easy to represent these structures as Python data structures, instead of
+  having to create a lot of function calls.
+
+  Each XML element of the content is represented as a list composed of:
+  1. The name of the element, a string,
+  2. The attributes of the element, a dictionary (optional), and
+  3+. The content of the element, if any.  Strings are simple text nodes and
+      lists are child elements.
+
+  Example 1:
+      <test/>
+  becomes
+      ['test']
+
+  Example 2:
+      <myelement a='value1' b='value2'>
+         <childtype>This is</childtype>
+         <childtype>it!</childtype>
+      </myelement>
+
+  becomes
+      ['myelement', {'a':'value1', 'b':'value2'},
+         ['childtype', 'This is'],
+         ['childtype', 'it!'],
+      ]
+
+  Args:
+    content:  The structured content to be converted.
+    encoding: The encoding to report on the first XML line.
+    pretty: True if we want pretty printing with indents and new lines.
+
+  Returns:
+    The XML content as a string.
+  """
+    # We create a huge list of all the elements of the file.
+    xml_parts = ['<?xml version="1.0" encoding="%s"?>' % encoding]
+    if pretty:
+        xml_parts.append("\n")
+    _ConstructContentList(xml_parts, content, pretty)
+
+    # Convert it to a string
+    return "".join(xml_parts)
+
+
+def _ConstructContentList(xml_parts, specification, pretty, level=0):
+    """ Appends the XML parts corresponding to the specification.
+
+  Args:
+    xml_parts: A list of XML parts to be appended to.
+    specification:  The specification of the element.  See EasyXml docs.
+    pretty: True if we want pretty printing with indents and new lines.
+    level: Indentation level.
+  """
+    # The first item in a specification is the name of the element.
+    if pretty:
+        indentation = "  " * level
+        new_line = "\n"
+    else:
+        indentation = ""
+        new_line = ""
+    name = specification[0]
+    if not isinstance(name, str):
+        raise Exception(
+            "The first item of an EasyXml specification should be "
+            "a string.  Specification was " + str(specification)
+        )
+    xml_parts.append(indentation + "<" + name)
+
+    # Optionally in second position is a dictionary of the attributes.
+    rest = specification[1:]
+    if rest and isinstance(rest[0], dict):
+        for at, val in sorted(rest[0].items()):
+            xml_parts.append(f' {at}="{_XmlEscape(val, attr=True)}"')
+        rest = rest[1:]
+    if rest:
+        xml_parts.append(">")
+        all_strings = reduce(lambda x, y: x and isinstance(y, str), rest, True)
+        multi_line = not all_strings
+        if multi_line and new_line:
+            xml_parts.append(new_line)
+        for child_spec in rest:
+            # If it's a string, append a text node.
+            # Otherwise recurse over that child definition
+            if isinstance(child_spec, str):
+                xml_parts.append(_XmlEscape(child_spec))
+            else:
+                _ConstructContentList(xml_parts, child_spec, pretty, level + 1)
+        if multi_line and indentation:
+            xml_parts.append(indentation)
+        xml_parts.append(f"</{name}>{new_line}")
+    else:
+        xml_parts.append("/>%s" % new_line)
+
+
+def WriteXmlIfChanged(content, path, encoding="utf-8", pretty=False,
+                      win32=(sys.platform == "win32")):
+    """ Writes the XML content to disk, touching the file only if it has changed.
+
+  Args:
+    content:  The structured content to be written.
+    path: Location of the file.
+    encoding: The encoding to report on the first line of the XML file.
+    pretty: True if we want pretty printing with indents and new lines.
+  """
+    xml_string = XmlToString(content, encoding, pretty)
+    if win32 and os.linesep != "\r\n":
+        xml_string = xml_string.replace("\n", "\r\n")
+
+    default_encoding = locale.getdefaultlocale()[1]
+    if default_encoding and default_encoding.upper() != encoding.upper():
+        xml_string = xml_string.encode(encoding)
+
+    # Get the old content
+    try:
+        with open(path) as file:
+            existing = file.read()
+    except OSError:
+        existing = None
+
+    # It has changed, write it
+    if existing != xml_string:
+        with open(path, "wb") as file:
+            file.write(xml_string)
+
+
+_xml_escape_map = {
+    '"': """,
+    "'": "'",
+    "<": "<",
+    ">": ">",
+    "&": "&",
+    "\n": "
",
+    "\r": "",
+}
+
+
+_xml_escape_re = re.compile("(%s)" % "|".join(map(re.escape, _xml_escape_map.keys())))
+
+
+def _XmlEscape(value, attr=False):
+    """ Escape a string for inclusion in XML."""
+
+    def replace(match):
+        m = match.string[match.start() : match.end()]
+        # don't replace single quotes in attrs
+        if attr and m == "'":
+            return m
+        return _xml_escape_map[m]
+
+    return _xml_escape_re.sub(replace, value)
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/easy_xml_test.py b/server/node_modules/node-gyp/gyp/pylib/gyp/easy_xml_test.py
new file mode 100755
index 0000000..342f693
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/easy_xml_test.py
@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2011 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+""" Unit tests for the easy_xml.py file. """
+
+import gyp.easy_xml as easy_xml
+import unittest
+
+from io import StringIO
+
+
+class TestSequenceFunctions(unittest.TestCase):
+    def setUp(self):
+        self.stderr = StringIO()
+
+    def test_EasyXml_simple(self):
+        self.assertEqual(
+            easy_xml.XmlToString(["test"]),
+            '<?xml version="1.0" encoding="utf-8"?><test/>',
+        )
+
+        self.assertEqual(
+            easy_xml.XmlToString(["test"], encoding="Windows-1252"),
+            '<?xml version="1.0" encoding="Windows-1252"?><test/>',
+        )
+
+    def test_EasyXml_simple_with_attributes(self):
+        self.assertEqual(
+            easy_xml.XmlToString(["test2", {"a": "value1", "b": "value2"}]),
+            '<?xml version="1.0" encoding="utf-8"?><test2 a="value1" b="value2"/>',
+        )
+
+    def test_EasyXml_escaping(self):
+        original = "<test>'\"\r&\nfoo"
+        converted = "<test>'"&
foo"
+        converted_apos = converted.replace("'", "'")
+        self.assertEqual(
+            easy_xml.XmlToString(["test3", {"a": original}, original]),
+            '<?xml version="1.0" encoding="utf-8"?><test3 a="%s">%s</test3>'
+            % (converted, converted_apos),
+        )
+
+    def test_EasyXml_pretty(self):
+        self.assertEqual(
+            easy_xml.XmlToString(
+                ["test3", ["GrandParent", ["Parent1", ["Child"]], ["Parent2"]]],
+                pretty=True,
+            ),
+            '<?xml version="1.0" encoding="utf-8"?>\n'
+            "<test3>\n"
+            "  <GrandParent>\n"
+            "    <Parent1>\n"
+            "      <Child/>\n"
+            "    </Parent1>\n"
+            "    <Parent2/>\n"
+            "  </GrandParent>\n"
+            "</test3>\n",
+        )
+
+    def test_EasyXml_complex(self):
+        # We want to create:
+        target = (
+            '<?xml version="1.0" encoding="utf-8"?>'
+            "<Project>"
+            '<PropertyGroup Label="Globals">'
+            "<ProjectGuid>{D2250C20-3A94-4FB9-AF73-11BC5B73884B}</ProjectGuid>"
+            "<Keyword>Win32Proj</Keyword>"
+            "<RootNamespace>automated_ui_tests</RootNamespace>"
+            "</PropertyGroup>"
+            '<Import Project="$(VCTargetsPath)\\Microsoft.Cpp.props"/>'
+            "<PropertyGroup "
+            "Condition=\"'$(Configuration)|$(Platform)'=="
+            '\'Debug|Win32\'" Label="Configuration">'
+            "<ConfigurationType>Application</ConfigurationType>"
+            "<CharacterSet>Unicode</CharacterSet>"
+            "</PropertyGroup>"
+            "</Project>"
+        )
+
+        xml = easy_xml.XmlToString(
+            [
+                "Project",
+                [
+                    "PropertyGroup",
+                    {"Label": "Globals"},
+                    ["ProjectGuid", "{D2250C20-3A94-4FB9-AF73-11BC5B73884B}"],
+                    ["Keyword", "Win32Proj"],
+                    ["RootNamespace", "automated_ui_tests"],
+                ],
+                ["Import", {"Project": "$(VCTargetsPath)\\Microsoft.Cpp.props"}],
+                [
+                    "PropertyGroup",
+                    {
+                        "Condition": "'$(Configuration)|$(Platform)'=='Debug|Win32'",
+                        "Label": "Configuration",
+                    },
+                    ["ConfigurationType", "Application"],
+                    ["CharacterSet", "Unicode"],
+                ],
+            ]
+        )
+        self.assertEqual(xml, target)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/flock_tool.py b/server/node_modules/node-gyp/gyp/pylib/gyp/flock_tool.py
new file mode 100755
index 0000000..1cb9815
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/flock_tool.py
@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+# Copyright (c) 2011 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""These functions are executed via gyp-flock-tool when using the Makefile
+generator.  Used on systems that don't have a built-in flock."""
+
+import fcntl
+import os
+import struct
+import subprocess
+import sys
+
+
+def main(args):
+    executor = FlockTool()
+    executor.Dispatch(args)
+
+
+class FlockTool:
+    """This class emulates the 'flock' command."""
+
+    def Dispatch(self, args):
+        """Dispatches a string command to a method."""
+        if len(args) < 1:
+            raise Exception("Not enough arguments")
+
+        method = "Exec%s" % self._CommandifyName(args[0])
+        getattr(self, method)(*args[1:])
+
+    def _CommandifyName(self, name_string):
+        """Transforms a tool name like copy-info-plist to CopyInfoPlist"""
+        return name_string.title().replace("-", "")
+
+    def ExecFlock(self, lockfile, *cmd_list):
+        """Emulates the most basic behavior of Linux's flock(1)."""
+        # Rely on exception handling to report errors.
+        # Note that the stock python on SunOS has a bug
+        # where fcntl.flock(fd, LOCK_EX) always fails
+        # with EBADF, that's why we use this F_SETLK
+        # hack instead.
+        fd = os.open(lockfile, os.O_WRONLY | os.O_NOCTTY | os.O_CREAT, 0o666)
+        if sys.platform.startswith("aix"):
+            # Python on AIX is compiled with LARGEFILE support, which changes the
+            # struct size.
+            op = struct.pack("hhIllqq", fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)
+        else:
+            op = struct.pack("hhllhhl", fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)
+        fcntl.fcntl(fd, fcntl.F_SETLK, op)
+        return subprocess.call(cmd_list)
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/__init__.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/analyzer.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/analyzer.py
new file mode 100644
index 0000000..f15df00
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/analyzer.py
@@ -0,0 +1,808 @@
+# Copyright (c) 2014 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+This script is intended for use as a GYP_GENERATOR. It takes as input (by way of
+the generator flag config_path) the path of a json file that dictates the files
+and targets to search for. The following keys are supported:
+files: list of paths (relative) of the files to search for.
+test_targets: unqualified target names to search for. Any target in this list
+that depends upon a file in |files| is output regardless of the type of target
+or chain of dependencies.
+additional_compile_targets: Unqualified targets to search for in addition to
+test_targets. Targets in the combined list that depend upon a file in |files|
+are not necessarily output. For example, if the target is of type none then the
+target is not output (but one of the descendants of the target will be).
+
+The following is output:
+error: only supplied if there is an error.
+compile_targets: minimal set of targets that directly or indirectly (for
+  targets of type none) depend on the files in |files| and is one of the
+  supplied targets or a target that one of the supplied targets depends on.
+  The expectation is this set of targets is passed into a build step. This list
+  always contains the output of test_targets as well.
+test_targets: set of targets from the supplied |test_targets| that either
+  directly or indirectly depend upon a file in |files|. This list if useful
+  if additional processing needs to be done for certain targets after the
+  build, such as running tests.
+status: outputs one of three values: none of the supplied files were found,
+  one of the include files changed so that it should be assumed everything
+  changed (in this case test_targets and compile_targets are not output) or at
+  least one file was found.
+invalid_targets: list of supplied targets that were not found.
+
+Example:
+Consider a graph like the following:
+  A     D
+ / \
+B   C
+A depends upon both B and C, A is of type none and B and C are executables.
+D is an executable, has no dependencies and nothing depends on it.
+If |additional_compile_targets| = ["A"], |test_targets| = ["B", "C"] and
+files = ["b.cc", "d.cc"] (B depends upon b.cc and D depends upon d.cc), then
+the following is output:
+|compile_targets| = ["B"] B must built as it depends upon the changed file b.cc
+and the supplied target A depends upon it. A is not output as a build_target
+as it is of type none with no rules and actions.
+|test_targets| = ["B"] B directly depends upon the change file b.cc.
+
+Even though the file d.cc, which D depends upon, has changed D is not output
+as it was not supplied by way of |additional_compile_targets| or |test_targets|.
+
+If the generator flag analyzer_output_path is specified, output is written
+there. Otherwise output is written to stdout.
+
+In Gyp the "all" target is shorthand for the root targets in the files passed
+to gyp. For example, if file "a.gyp" contains targets "a1" and
+"a2", and file "b.gyp" contains targets "b1" and "b2" and "a2" has a dependency
+on "b2" and gyp is supplied "a.gyp" then "all" consists of "a1" and "a2".
+Notice that "b1" and "b2" are not in the "all" target as "b.gyp" was not
+directly supplied to gyp. OTOH if both "a.gyp" and "b.gyp" are supplied to gyp
+then the "all" target includes "b1" and "b2".
+"""
+
+
+import gyp.common
+import json
+import os
+import posixpath
+
+debug = False
+
+found_dependency_string = "Found dependency"
+no_dependency_string = "No dependencies"
+# Status when it should be assumed that everything has changed.
+all_changed_string = "Found dependency (all)"
+
+# MatchStatus is used indicate if and how a target depends upon the supplied
+# sources.
+# The target's sources contain one of the supplied paths.
+MATCH_STATUS_MATCHES = 1
+# The target has a dependency on another target that contains one of the
+# supplied paths.
+MATCH_STATUS_MATCHES_BY_DEPENDENCY = 2
+# The target's sources weren't in the supplied paths and none of the target's
+# dependencies depend upon a target that matched.
+MATCH_STATUS_DOESNT_MATCH = 3
+# The target doesn't contain the source, but the dependent targets have not yet
+# been visited to determine a more specific status yet.
+MATCH_STATUS_TBD = 4
+
+generator_supports_multiple_toolsets = gyp.common.CrossCompileRequested()
+
+generator_wants_static_library_dependencies_adjusted = False
+
+generator_default_variables = {}
+for dirname in [
+    "INTERMEDIATE_DIR",
+    "SHARED_INTERMEDIATE_DIR",
+    "PRODUCT_DIR",
+    "LIB_DIR",
+    "SHARED_LIB_DIR",
+]:
+    generator_default_variables[dirname] = "!!!"
+
+for unused in [
+    "RULE_INPUT_PATH",
+    "RULE_INPUT_ROOT",
+    "RULE_INPUT_NAME",
+    "RULE_INPUT_DIRNAME",
+    "RULE_INPUT_EXT",
+    "EXECUTABLE_PREFIX",
+    "EXECUTABLE_SUFFIX",
+    "STATIC_LIB_PREFIX",
+    "STATIC_LIB_SUFFIX",
+    "SHARED_LIB_PREFIX",
+    "SHARED_LIB_SUFFIX",
+    "CONFIGURATION_NAME",
+]:
+    generator_default_variables[unused] = ""
+
+
+def _ToGypPath(path):
+    """Converts a path to the format used by gyp."""
+    if os.sep == "\\" and os.altsep == "/":
+        return path.replace("\\", "/")
+    return path
+
+
+def _ResolveParent(path, base_path_components):
+    """Resolves |path|, which starts with at least one '../'. Returns an empty
+  string if the path shouldn't be considered. See _AddSources() for a
+  description of |base_path_components|."""
+    depth = 0
+    while path.startswith("../"):
+        depth += 1
+        path = path[3:]
+    # Relative includes may go outside the source tree. For example, an action may
+    # have inputs in /usr/include, which are not in the source tree.
+    if depth > len(base_path_components):
+        return ""
+    if depth == len(base_path_components):
+        return path
+    return (
+        "/".join(base_path_components[0 : len(base_path_components) - depth])
+        + "/"
+        + path
+    )
+
+
+def _AddSources(sources, base_path, base_path_components, result):
+    """Extracts valid sources from |sources| and adds them to |result|. Each
+  source file is relative to |base_path|, but may contain '..'. To make
+  resolving '..' easier |base_path_components| contains each of the
+  directories in |base_path|. Additionally each source may contain variables.
+  Such sources are ignored as it is assumed dependencies on them are expressed
+  and tracked in some other means."""
+    # NOTE: gyp paths are always posix style.
+    for source in sources:
+        if not len(source) or source.startswith("!!!") or source.startswith("$"):
+            continue
+        # variable expansion may lead to //.
+        org_source = source
+        source = source[0] + source[1:].replace("//", "/")
+        if source.startswith("../"):
+            source = _ResolveParent(source, base_path_components)
+            if len(source):
+                result.append(source)
+            continue
+        result.append(base_path + source)
+        if debug:
+            print("AddSource", org_source, result[len(result) - 1])
+
+
+def _ExtractSourcesFromAction(action, base_path, base_path_components, results):
+    if "inputs" in action:
+        _AddSources(action["inputs"], base_path, base_path_components, results)
+
+
+def _ToLocalPath(toplevel_dir, path):
+    """Converts |path| to a path relative to |toplevel_dir|."""
+    if path == toplevel_dir:
+        return ""
+    if path.startswith(toplevel_dir + "/"):
+        return path[len(toplevel_dir) + len("/") :]
+    return path
+
+
+def _ExtractSources(target, target_dict, toplevel_dir):
+    # |target| is either absolute or relative and in the format of the OS. Gyp
+    # source paths are always posix. Convert |target| to a posix path relative to
+    # |toplevel_dir_|. This is done to make it easy to build source paths.
+    base_path = posixpath.dirname(_ToLocalPath(toplevel_dir, _ToGypPath(target)))
+    base_path_components = base_path.split("/")
+
+    # Add a trailing '/' so that _AddSources() can easily build paths.
+    if len(base_path):
+        base_path += "/"
+
+    if debug:
+        print("ExtractSources", target, base_path)
+
+    results = []
+    if "sources" in target_dict:
+        _AddSources(target_dict["sources"], base_path, base_path_components, results)
+    # Include the inputs from any actions. Any changes to these affect the
+    # resulting output.
+    if "actions" in target_dict:
+        for action in target_dict["actions"]:
+            _ExtractSourcesFromAction(action, base_path, base_path_components, results)
+    if "rules" in target_dict:
+        for rule in target_dict["rules"]:
+            _ExtractSourcesFromAction(rule, base_path, base_path_components, results)
+
+    return results
+
+
+class Target:
+    """Holds information about a particular target:
+  deps: set of Targets this Target depends upon. This is not recursive, only the
+    direct dependent Targets.
+  match_status: one of the MatchStatus values.
+  back_deps: set of Targets that have a dependency on this Target.
+  visited: used during iteration to indicate whether we've visited this target.
+    This is used for two iterations, once in building the set of Targets and
+    again in _GetBuildTargets().
+  name: fully qualified name of the target.
+  requires_build: True if the target type is such that it needs to be built.
+    See _DoesTargetTypeRequireBuild for details.
+  added_to_compile_targets: used when determining if the target was added to the
+    set of targets that needs to be built.
+  in_roots: true if this target is a descendant of one of the root nodes.
+  is_executable: true if the type of target is executable.
+  is_static_library: true if the type of target is static_library.
+  is_or_has_linked_ancestor: true if the target does a link (eg executable), or
+    if there is a target in back_deps that does a link."""
+
+    def __init__(self, name):
+        self.deps = set()
+        self.match_status = MATCH_STATUS_TBD
+        self.back_deps = set()
+        self.name = name
+        # TODO(sky): I don't like hanging this off Target. This state is specific
+        # to certain functions and should be isolated there.
+        self.visited = False
+        self.requires_build = False
+        self.added_to_compile_targets = False
+        self.in_roots = False
+        self.is_executable = False
+        self.is_static_library = False
+        self.is_or_has_linked_ancestor = False
+
+
+class Config:
+    """Details what we're looking for
+  files: set of files to search for
+  targets: see file description for details."""
+
+    def __init__(self):
+        self.files = []
+        self.targets = set()
+        self.additional_compile_target_names = set()
+        self.test_target_names = set()
+
+    def Init(self, params):
+        """Initializes Config. This is a separate method as it raises an exception
+    if there is a parse error."""
+        generator_flags = params.get("generator_flags", {})
+        config_path = generator_flags.get("config_path", None)
+        if not config_path:
+            return
+        try:
+            f = open(config_path)
+            config = json.load(f)
+            f.close()
+        except OSError:
+            raise Exception("Unable to open file " + config_path)
+        except ValueError as e:
+            raise Exception("Unable to parse config file " + config_path + str(e))
+        if not isinstance(config, dict):
+            raise Exception("config_path must be a JSON file containing a dictionary")
+        self.files = config.get("files", [])
+        self.additional_compile_target_names = set(
+            config.get("additional_compile_targets", [])
+        )
+        self.test_target_names = set(config.get("test_targets", []))
+
+
+def _WasBuildFileModified(build_file, data, files, toplevel_dir):
+    """Returns true if the build file |build_file| is either in |files| or
+  one of the files included by |build_file| is in |files|. |toplevel_dir| is
+  the root of the source tree."""
+    if _ToLocalPath(toplevel_dir, _ToGypPath(build_file)) in files:
+        if debug:
+            print("gyp file modified", build_file)
+        return True
+
+    # First element of included_files is the file itself.
+    if len(data[build_file]["included_files"]) <= 1:
+        return False
+
+    for include_file in data[build_file]["included_files"][1:]:
+        # |included_files| are relative to the directory of the |build_file|.
+        rel_include_file = _ToGypPath(
+            gyp.common.UnrelativePath(include_file, build_file)
+        )
+        if _ToLocalPath(toplevel_dir, rel_include_file) in files:
+            if debug:
+                print(
+                    "included gyp file modified, gyp_file=",
+                    build_file,
+                    "included file=",
+                    rel_include_file,
+                )
+            return True
+    return False
+
+
+def _GetOrCreateTargetByName(targets, target_name):
+    """Creates or returns the Target at targets[target_name]. If there is no
+  Target for |target_name| one is created. Returns a tuple of whether a new
+  Target was created and the Target."""
+    if target_name in targets:
+        return False, targets[target_name]
+    target = Target(target_name)
+    targets[target_name] = target
+    return True, target
+
+
+def _DoesTargetTypeRequireBuild(target_dict):
+    """Returns true if the target type is such that it needs to be built."""
+    # If a 'none' target has rules or actions we assume it requires a build.
+    return bool(
+        target_dict["type"] != "none"
+        or target_dict.get("actions")
+        or target_dict.get("rules")
+    )
+
+
+def _GenerateTargets(data, target_list, target_dicts, toplevel_dir, files, build_files):
+    """Returns a tuple of the following:
+  . A dictionary mapping from fully qualified name to Target.
+  . A list of the targets that have a source file in |files|.
+  . Targets that constitute the 'all' target. See description at top of file
+    for details on the 'all' target.
+  This sets the |match_status| of the targets that contain any of the source
+  files in |files| to MATCH_STATUS_MATCHES.
+  |toplevel_dir| is the root of the source tree."""
+    # Maps from target name to Target.
+    name_to_target = {}
+
+    # Targets that matched.
+    matching_targets = []
+
+    # Queue of targets to visit.
+    targets_to_visit = target_list[:]
+
+    # Maps from build file to a boolean indicating whether the build file is in
+    # |files|.
+    build_file_in_files = {}
+
+    # Root targets across all files.
+    roots = set()
+
+    # Set of Targets in |build_files|.
+    build_file_targets = set()
+
+    while len(targets_to_visit) > 0:
+        target_name = targets_to_visit.pop()
+        created_target, target = _GetOrCreateTargetByName(name_to_target, target_name)
+        if created_target:
+            roots.add(target)
+        elif target.visited:
+            continue
+
+        target.visited = True
+        target.requires_build = _DoesTargetTypeRequireBuild(target_dicts[target_name])
+        target_type = target_dicts[target_name]["type"]
+        target.is_executable = target_type == "executable"
+        target.is_static_library = target_type == "static_library"
+        target.is_or_has_linked_ancestor = (
+            target_type == "executable" or target_type == "shared_library"
+        )
+
+        build_file = gyp.common.ParseQualifiedTarget(target_name)[0]
+        if build_file not in build_file_in_files:
+            build_file_in_files[build_file] = _WasBuildFileModified(
+                build_file, data, files, toplevel_dir
+            )
+
+        if build_file in build_files:
+            build_file_targets.add(target)
+
+        # If a build file (or any of its included files) is modified we assume all
+        # targets in the file are modified.
+        if build_file_in_files[build_file]:
+            print("matching target from modified build file", target_name)
+            target.match_status = MATCH_STATUS_MATCHES
+            matching_targets.append(target)
+        else:
+            sources = _ExtractSources(
+                target_name, target_dicts[target_name], toplevel_dir
+            )
+            for source in sources:
+                if _ToGypPath(os.path.normpath(source)) in files:
+                    print("target", target_name, "matches", source)
+                    target.match_status = MATCH_STATUS_MATCHES
+                    matching_targets.append(target)
+                    break
+
+        # Add dependencies to visit as well as updating back pointers for deps.
+        for dep in target_dicts[target_name].get("dependencies", []):
+            targets_to_visit.append(dep)
+
+            created_dep_target, dep_target = _GetOrCreateTargetByName(
+                name_to_target, dep
+            )
+            if not created_dep_target:
+                roots.discard(dep_target)
+
+            target.deps.add(dep_target)
+            dep_target.back_deps.add(target)
+
+    return name_to_target, matching_targets, roots & build_file_targets
+
+
+def _GetUnqualifiedToTargetMapping(all_targets, to_find):
+    """Returns a tuple of the following:
+  . mapping (dictionary) from unqualified name to Target for all the
+    Targets in |to_find|.
+  . any target names not found. If this is empty all targets were found."""
+    result = {}
+    if not to_find:
+        return {}, []
+    to_find = set(to_find)
+    for target_name in all_targets.keys():
+        extracted = gyp.common.ParseQualifiedTarget(target_name)
+        if len(extracted) > 1 and extracted[1] in to_find:
+            to_find.remove(extracted[1])
+            result[extracted[1]] = all_targets[target_name]
+            if not to_find:
+                return result, []
+    return result, [x for x in to_find]
+
+
+def _DoesTargetDependOnMatchingTargets(target):
+    """Returns true if |target| or any of its dependencies is one of the
+  targets containing the files supplied as input to analyzer. This updates
+  |matches| of the Targets as it recurses.
+  target: the Target to look for."""
+    if target.match_status == MATCH_STATUS_DOESNT_MATCH:
+        return False
+    if (
+        target.match_status == MATCH_STATUS_MATCHES
+        or target.match_status == MATCH_STATUS_MATCHES_BY_DEPENDENCY
+    ):
+        return True
+    for dep in target.deps:
+        if _DoesTargetDependOnMatchingTargets(dep):
+            target.match_status = MATCH_STATUS_MATCHES_BY_DEPENDENCY
+            print("\t", target.name, "matches by dep", dep.name)
+            return True
+    target.match_status = MATCH_STATUS_DOESNT_MATCH
+    return False
+
+
+def _GetTargetsDependingOnMatchingTargets(possible_targets):
+    """Returns the list of Targets in |possible_targets| that depend (either
+  directly on indirectly) on at least one of the targets containing the files
+  supplied as input to analyzer.
+  possible_targets: targets to search from."""
+    found = []
+    print("Targets that matched by dependency:")
+    for target in possible_targets:
+        if _DoesTargetDependOnMatchingTargets(target):
+            found.append(target)
+    return found
+
+
+def _AddCompileTargets(target, roots, add_if_no_ancestor, result):
+    """Recurses through all targets that depend on |target|, adding all targets
+  that need to be built (and are in |roots|) to |result|.
+  roots: set of root targets.
+  add_if_no_ancestor: If true and there are no ancestors of |target| then add
+  |target| to |result|. |target| must still be in |roots|.
+  result: targets that need to be built are added here."""
+    if target.visited:
+        return
+
+    target.visited = True
+    target.in_roots = target in roots
+
+    for back_dep_target in target.back_deps:
+        _AddCompileTargets(back_dep_target, roots, False, result)
+        target.added_to_compile_targets |= back_dep_target.added_to_compile_targets
+        target.in_roots |= back_dep_target.in_roots
+        target.is_or_has_linked_ancestor |= back_dep_target.is_or_has_linked_ancestor
+
+    # Always add 'executable' targets. Even though they may be built by other
+    # targets that depend upon them it makes detection of what is going to be
+    # built easier.
+    # And always add static_libraries that have no dependencies on them from
+    # linkables. This is necessary as the other dependencies on them may be
+    # static libraries themselves, which are not compile time dependencies.
+    if target.in_roots and (
+        target.is_executable
+        or (
+            not target.added_to_compile_targets
+            and (add_if_no_ancestor or target.requires_build)
+        )
+        or (
+            target.is_static_library
+            and add_if_no_ancestor
+            and not target.is_or_has_linked_ancestor
+        )
+    ):
+        print(
+            "\t\tadding to compile targets",
+            target.name,
+            "executable",
+            target.is_executable,
+            "added_to_compile_targets",
+            target.added_to_compile_targets,
+            "add_if_no_ancestor",
+            add_if_no_ancestor,
+            "requires_build",
+            target.requires_build,
+            "is_static_library",
+            target.is_static_library,
+            "is_or_has_linked_ancestor",
+            target.is_or_has_linked_ancestor,
+        )
+        result.add(target)
+        target.added_to_compile_targets = True
+
+
+def _GetCompileTargets(matching_targets, supplied_targets):
+    """Returns the set of Targets that require a build.
+  matching_targets: targets that changed and need to be built.
+  supplied_targets: set of targets supplied to analyzer to search from."""
+    result = set()
+    for target in matching_targets:
+        print("finding compile targets for match", target.name)
+        _AddCompileTargets(target, supplied_targets, True, result)
+    return result
+
+
+def _WriteOutput(params, **values):
+    """Writes the output, either to stdout or a file is specified."""
+    if "error" in values:
+        print("Error:", values["error"])
+    if "status" in values:
+        print(values["status"])
+    if "targets" in values:
+        values["targets"].sort()
+        print("Supplied targets that depend on changed files:")
+        for target in values["targets"]:
+            print("\t", target)
+    if "invalid_targets" in values:
+        values["invalid_targets"].sort()
+        print("The following targets were not found:")
+        for target in values["invalid_targets"]:
+            print("\t", target)
+    if "build_targets" in values:
+        values["build_targets"].sort()
+        print("Targets that require a build:")
+        for target in values["build_targets"]:
+            print("\t", target)
+    if "compile_targets" in values:
+        values["compile_targets"].sort()
+        print("Targets that need to be built:")
+        for target in values["compile_targets"]:
+            print("\t", target)
+    if "test_targets" in values:
+        values["test_targets"].sort()
+        print("Test targets:")
+        for target in values["test_targets"]:
+            print("\t", target)
+
+    output_path = params.get("generator_flags", {}).get("analyzer_output_path", None)
+    if not output_path:
+        print(json.dumps(values))
+        return
+    try:
+        f = open(output_path, "w")
+        f.write(json.dumps(values) + "\n")
+        f.close()
+    except OSError as e:
+        print("Error writing to output file", output_path, str(e))
+
+
+def _WasGypIncludeFileModified(params, files):
+    """Returns true if one of the files in |files| is in the set of included
+  files."""
+    if params["options"].includes:
+        for include in params["options"].includes:
+            if _ToGypPath(os.path.normpath(include)) in files:
+                print("Include file modified, assuming all changed", include)
+                return True
+    return False
+
+
+def _NamesNotIn(names, mapping):
+    """Returns a list of the values in |names| that are not in |mapping|."""
+    return [name for name in names if name not in mapping]
+
+
+def _LookupTargets(names, mapping):
+    """Returns a list of the mapping[name] for each value in |names| that is in
+  |mapping|."""
+    return [mapping[name] for name in names if name in mapping]
+
+
+def CalculateVariables(default_variables, params):
+    """Calculate additional variables for use in the build (called by gyp)."""
+    flavor = gyp.common.GetFlavor(params)
+    if flavor == "mac":
+        default_variables.setdefault("OS", "mac")
+    elif flavor == "win":
+        default_variables.setdefault("OS", "win")
+        gyp.msvs_emulation.CalculateCommonVariables(default_variables, params)
+    else:
+        operating_system = flavor
+        if flavor == "android":
+            operating_system = "linux"  # Keep this legacy behavior for now.
+        default_variables.setdefault("OS", operating_system)
+
+
+class TargetCalculator:
+    """Calculates the matching test_targets and matching compile_targets."""
+
+    def __init__(
+        self,
+        files,
+        additional_compile_target_names,
+        test_target_names,
+        data,
+        target_list,
+        target_dicts,
+        toplevel_dir,
+        build_files,
+    ):
+        self._additional_compile_target_names = set(additional_compile_target_names)
+        self._test_target_names = set(test_target_names)
+        (
+            self._name_to_target,
+            self._changed_targets,
+            self._root_targets,
+        ) = _GenerateTargets(
+            data, target_list, target_dicts, toplevel_dir, frozenset(files), build_files
+        )
+        (
+            self._unqualified_mapping,
+            self.invalid_targets,
+        ) = _GetUnqualifiedToTargetMapping(
+            self._name_to_target, self._supplied_target_names_no_all()
+        )
+
+    def _supplied_target_names(self):
+        return self._additional_compile_target_names | self._test_target_names
+
+    def _supplied_target_names_no_all(self):
+        """Returns the supplied test targets without 'all'."""
+        result = self._supplied_target_names()
+        result.discard("all")
+        return result
+
+    def is_build_impacted(self):
+        """Returns true if the supplied files impact the build at all."""
+        return self._changed_targets
+
+    def find_matching_test_target_names(self):
+        """Returns the set of output test targets."""
+        assert self.is_build_impacted()
+        # Find the test targets first. 'all' is special cased to mean all the
+        # root targets. To deal with all the supplied |test_targets| are expanded
+        # to include the root targets during lookup. If any of the root targets
+        # match, we remove it and replace it with 'all'.
+        test_target_names_no_all = set(self._test_target_names)
+        test_target_names_no_all.discard("all")
+        test_targets_no_all = _LookupTargets(
+            test_target_names_no_all, self._unqualified_mapping
+        )
+        test_target_names_contains_all = "all" in self._test_target_names
+        if test_target_names_contains_all:
+            test_targets = [
+                x for x in (set(test_targets_no_all) | set(self._root_targets))
+            ]
+        else:
+            test_targets = [x for x in test_targets_no_all]
+        print("supplied test_targets")
+        for target_name in self._test_target_names:
+            print("\t", target_name)
+        print("found test_targets")
+        for target in test_targets:
+            print("\t", target.name)
+        print("searching for matching test targets")
+        matching_test_targets = _GetTargetsDependingOnMatchingTargets(test_targets)
+        matching_test_targets_contains_all = test_target_names_contains_all and set(
+            matching_test_targets
+        ) & set(self._root_targets)
+        if matching_test_targets_contains_all:
+            # Remove any of the targets for all that were not explicitly supplied,
+            # 'all' is subsequentely added to the matching names below.
+            matching_test_targets = [
+                x for x in (set(matching_test_targets) & set(test_targets_no_all))
+            ]
+        print("matched test_targets")
+        for target in matching_test_targets:
+            print("\t", target.name)
+        matching_target_names = [
+            gyp.common.ParseQualifiedTarget(target.name)[1]
+            for target in matching_test_targets
+        ]
+        if matching_test_targets_contains_all:
+            matching_target_names.append("all")
+            print("\tall")
+        return matching_target_names
+
+    def find_matching_compile_target_names(self):
+        """Returns the set of output compile targets."""
+        assert self.is_build_impacted()
+        # Compile targets are found by searching up from changed targets.
+        # Reset the visited status for _GetBuildTargets.
+        for target in self._name_to_target.values():
+            target.visited = False
+
+        supplied_targets = _LookupTargets(
+            self._supplied_target_names_no_all(), self._unqualified_mapping
+        )
+        if "all" in self._supplied_target_names():
+            supplied_targets = [
+                x for x in (set(supplied_targets) | set(self._root_targets))
+            ]
+        print("Supplied test_targets & compile_targets")
+        for target in supplied_targets:
+            print("\t", target.name)
+        print("Finding compile targets")
+        compile_targets = _GetCompileTargets(self._changed_targets, supplied_targets)
+        return [
+            gyp.common.ParseQualifiedTarget(target.name)[1]
+            for target in compile_targets
+        ]
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    """Called by gyp as the final stage. Outputs results."""
+    config = Config()
+    try:
+        config.Init(params)
+
+        if not config.files:
+            raise Exception(
+                "Must specify files to analyze via config_path generator " "flag"
+            )
+
+        toplevel_dir = _ToGypPath(os.path.abspath(params["options"].toplevel_dir))
+        if debug:
+            print("toplevel_dir", toplevel_dir)
+
+        if _WasGypIncludeFileModified(params, config.files):
+            result_dict = {
+                "status": all_changed_string,
+                "test_targets": list(config.test_target_names),
+                "compile_targets": list(
+                    config.additional_compile_target_names | config.test_target_names
+                ),
+            }
+            _WriteOutput(params, **result_dict)
+            return
+
+        calculator = TargetCalculator(
+            config.files,
+            config.additional_compile_target_names,
+            config.test_target_names,
+            data,
+            target_list,
+            target_dicts,
+            toplevel_dir,
+            params["build_files"],
+        )
+        if not calculator.is_build_impacted():
+            result_dict = {
+                "status": no_dependency_string,
+                "test_targets": [],
+                "compile_targets": [],
+            }
+            if calculator.invalid_targets:
+                result_dict["invalid_targets"] = calculator.invalid_targets
+            _WriteOutput(params, **result_dict)
+            return
+
+        test_target_names = calculator.find_matching_test_target_names()
+        compile_target_names = calculator.find_matching_compile_target_names()
+        found_at_least_one_target = compile_target_names or test_target_names
+        result_dict = {
+            "test_targets": test_target_names,
+            "status": found_dependency_string
+            if found_at_least_one_target
+            else no_dependency_string,
+            "compile_targets": list(set(compile_target_names) | set(test_target_names)),
+        }
+        if calculator.invalid_targets:
+            result_dict["invalid_targets"] = calculator.invalid_targets
+        _WriteOutput(params, **result_dict)
+
+    except Exception as e:
+        _WriteOutput(params, error=str(e))
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/android.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/android.py
new file mode 100644
index 0000000..cdf1a48
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/android.py
@@ -0,0 +1,1173 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Notes:
+#
+# This generates makefiles suitable for inclusion into the Android build system
+# via an Android.mk file. It is based on make.py, the standard makefile
+# generator.
+#
+# The code below generates a separate .mk file for each target, but
+# all are sourced by the top-level GypAndroid.mk.  This means that all
+# variables in .mk-files clobber one another, and furthermore that any
+# variables set potentially clash with other Android build system variables.
+# Try to avoid setting global variables where possible.
+
+
+import gyp
+import gyp.common
+import gyp.generator.make as make  # Reuse global functions from make backend.
+import os
+import re
+import subprocess
+
+generator_default_variables = {
+    "OS": "android",
+    "EXECUTABLE_PREFIX": "",
+    "EXECUTABLE_SUFFIX": "",
+    "STATIC_LIB_PREFIX": "lib",
+    "SHARED_LIB_PREFIX": "lib",
+    "STATIC_LIB_SUFFIX": ".a",
+    "SHARED_LIB_SUFFIX": ".so",
+    "INTERMEDIATE_DIR": "$(gyp_intermediate_dir)",
+    "SHARED_INTERMEDIATE_DIR": "$(gyp_shared_intermediate_dir)",
+    "PRODUCT_DIR": "$(gyp_shared_intermediate_dir)",
+    "SHARED_LIB_DIR": "$(builddir)/lib.$(TOOLSET)",
+    "LIB_DIR": "$(obj).$(TOOLSET)",
+    "RULE_INPUT_ROOT": "%(INPUT_ROOT)s",  # This gets expanded by Python.
+    "RULE_INPUT_DIRNAME": "%(INPUT_DIRNAME)s",  # This gets expanded by Python.
+    "RULE_INPUT_PATH": "$(RULE_SOURCES)",
+    "RULE_INPUT_EXT": "$(suffix $<)",
+    "RULE_INPUT_NAME": "$(notdir $<)",
+    "CONFIGURATION_NAME": "$(GYP_CONFIGURATION)",
+}
+
+# Make supports multiple toolsets
+generator_supports_multiple_toolsets = True
+
+
+# Generator-specific gyp specs.
+generator_additional_non_configuration_keys = [
+    # Boolean to declare that this target does not want its name mangled.
+    "android_unmangled_name",
+    # Map of android build system variables to set.
+    "aosp_build_settings",
+]
+generator_additional_path_sections = []
+generator_extra_sources_for_rules = []
+
+
+ALL_MODULES_FOOTER = """\
+# "gyp_all_modules" is a concatenation of the "gyp_all_modules" targets from
+# all the included sub-makefiles. This is just here to clarify.
+gyp_all_modules:
+"""
+
+header = """\
+# This file is generated by gyp; do not edit.
+
+"""
+
+# Map gyp target types to Android module classes.
+MODULE_CLASSES = {
+    "static_library": "STATIC_LIBRARIES",
+    "shared_library": "SHARED_LIBRARIES",
+    "executable": "EXECUTABLES",
+}
+
+
+def IsCPPExtension(ext):
+    return make.COMPILABLE_EXTENSIONS.get(ext) == "cxx"
+
+
+def Sourceify(path):
+    """Convert a path to its source directory form. The Android backend does not
+    support options.generator_output, so this function is a noop."""
+    return path
+
+
+# Map from qualified target to path to output.
+# For Android, the target of these maps is a tuple ('static', 'modulename'),
+# ('dynamic', 'modulename'), or ('path', 'some/path') instead of a string,
+# since we link by module.
+target_outputs = {}
+# Map from qualified target to any linkable output.  A subset
+# of target_outputs.  E.g. when mybinary depends on liba, we want to
+# include liba in the linker line; when otherbinary depends on
+# mybinary, we just want to build mybinary first.
+target_link_deps = {}
+
+
+class AndroidMkWriter:
+    """AndroidMkWriter packages up the writing of one target-specific Android.mk.
+
+    Its only real entry point is Write(), and is mostly used for namespacing.
+    """
+
+    def __init__(self, android_top_dir):
+        self.android_top_dir = android_top_dir
+
+    def Write(
+        self,
+        qualified_target,
+        relative_target,
+        base_path,
+        output_filename,
+        spec,
+        configs,
+        part_of_all,
+        write_alias_target,
+        sdk_version,
+    ):
+        """The main entry point: writes a .mk file for a single target.
+
+        Arguments:
+          qualified_target: target we're generating
+          relative_target: qualified target name relative to the root
+          base_path: path relative to source root we're building in, used to resolve
+                     target-relative paths
+          output_filename: output .mk file name to write
+          spec, configs: gyp info
+          part_of_all: flag indicating this target is part of 'all'
+          write_alias_target: flag indicating whether to create short aliases for
+                              this target
+          sdk_version: what to emit for LOCAL_SDK_VERSION in output
+        """
+        gyp.common.EnsureDirExists(output_filename)
+
+        self.fp = open(output_filename, "w")
+
+        self.fp.write(header)
+
+        self.qualified_target = qualified_target
+        self.relative_target = relative_target
+        self.path = base_path
+        self.target = spec["target_name"]
+        self.type = spec["type"]
+        self.toolset = spec["toolset"]
+
+        deps, link_deps = self.ComputeDeps(spec)
+
+        # Some of the generation below can add extra output, sources, or
+        # link dependencies.  All of the out params of the functions that
+        # follow use names like extra_foo.
+        extra_outputs = []
+        extra_sources = []
+
+        self.android_class = MODULE_CLASSES.get(self.type, "GYP")
+        self.android_module = self.ComputeAndroidModule(spec)
+        (self.android_stem, self.android_suffix) = self.ComputeOutputParts(spec)
+        self.output = self.output_binary = self.ComputeOutput(spec)
+
+        # Standard header.
+        self.WriteLn("include $(CLEAR_VARS)\n")
+
+        # Module class and name.
+        self.WriteLn("LOCAL_MODULE_CLASS := " + self.android_class)
+        self.WriteLn("LOCAL_MODULE := " + self.android_module)
+        # Only emit LOCAL_MODULE_STEM if it's different to LOCAL_MODULE.
+        # The library module classes fail if the stem is set. ComputeOutputParts
+        # makes sure that stem == modulename in these cases.
+        if self.android_stem != self.android_module:
+            self.WriteLn("LOCAL_MODULE_STEM := " + self.android_stem)
+        self.WriteLn("LOCAL_MODULE_SUFFIX := " + self.android_suffix)
+        if self.toolset == "host":
+            self.WriteLn("LOCAL_IS_HOST_MODULE := true")
+            self.WriteLn("LOCAL_MULTILIB := $(GYP_HOST_MULTILIB)")
+        elif sdk_version > 0:
+            self.WriteLn(
+                "LOCAL_MODULE_TARGET_ARCH := " "$(TARGET_$(GYP_VAR_PREFIX)ARCH)"
+            )
+            self.WriteLn("LOCAL_SDK_VERSION := %s" % sdk_version)
+
+        # Grab output directories; needed for Actions and Rules.
+        if self.toolset == "host":
+            self.WriteLn(
+                "gyp_intermediate_dir := "
+                "$(call local-intermediates-dir,,$(GYP_HOST_VAR_PREFIX))"
+            )
+        else:
+            self.WriteLn(
+                "gyp_intermediate_dir := "
+                "$(call local-intermediates-dir,,$(GYP_VAR_PREFIX))"
+            )
+        self.WriteLn(
+            "gyp_shared_intermediate_dir := "
+            "$(call intermediates-dir-for,GYP,shared,,,$(GYP_VAR_PREFIX))"
+        )
+        self.WriteLn()
+
+        # List files this target depends on so that actions/rules/copies/sources
+        # can depend on the list.
+        # TODO: doesn't pull in things through transitive link deps; needed?
+        target_dependencies = [x[1] for x in deps if x[0] == "path"]
+        self.WriteLn("# Make sure our deps are built first.")
+        self.WriteList(
+            target_dependencies, "GYP_TARGET_DEPENDENCIES", local_pathify=True
+        )
+
+        # Actions must come first, since they can generate more OBJs for use below.
+        if "actions" in spec:
+            self.WriteActions(spec["actions"], extra_sources, extra_outputs)
+
+        # Rules must be early like actions.
+        if "rules" in spec:
+            self.WriteRules(spec["rules"], extra_sources, extra_outputs)
+
+        if "copies" in spec:
+            self.WriteCopies(spec["copies"], extra_outputs)
+
+        # GYP generated outputs.
+        self.WriteList(extra_outputs, "GYP_GENERATED_OUTPUTS", local_pathify=True)
+
+        # Set LOCAL_ADDITIONAL_DEPENDENCIES so that Android's build rules depend
+        # on both our dependency targets and our generated files.
+        self.WriteLn("# Make sure our deps and generated files are built first.")
+        self.WriteLn(
+            "LOCAL_ADDITIONAL_DEPENDENCIES := $(GYP_TARGET_DEPENDENCIES) "
+            "$(GYP_GENERATED_OUTPUTS)"
+        )
+        self.WriteLn()
+
+        # Sources.
+        if spec.get("sources", []) or extra_sources:
+            self.WriteSources(spec, configs, extra_sources)
+
+        self.WriteTarget(
+            spec, configs, deps, link_deps, part_of_all, write_alias_target
+        )
+
+        # Update global list of target outputs, used in dependency tracking.
+        target_outputs[qualified_target] = ("path", self.output_binary)
+
+        # Update global list of link dependencies.
+        if self.type == "static_library":
+            target_link_deps[qualified_target] = ("static", self.android_module)
+        elif self.type == "shared_library":
+            target_link_deps[qualified_target] = ("shared", self.android_module)
+
+        self.fp.close()
+        return self.android_module
+
+    def WriteActions(self, actions, extra_sources, extra_outputs):
+        """Write Makefile code for any 'actions' from the gyp input.
+
+        extra_sources: a list that will be filled in with newly generated source
+                       files, if any
+        extra_outputs: a list that will be filled in with any outputs of these
+                       actions (used to make other pieces dependent on these
+                       actions)
+        """
+        for action in actions:
+            name = make.StringToMakefileVariable(
+                "{}_{}".format(self.relative_target, action["action_name"])
+            )
+            self.WriteLn('### Rules for action "%s":' % action["action_name"])
+            inputs = action["inputs"]
+            outputs = action["outputs"]
+
+            # Build up a list of outputs.
+            # Collect the output dirs we'll need.
+            dirs = set()
+            for out in outputs:
+                if not out.startswith("$"):
+                    print(
+                        'WARNING: Action for target "%s" writes output to local path '
+                        '"%s".' % (self.target, out)
+                    )
+                dir = os.path.split(out)[0]
+                if dir:
+                    dirs.add(dir)
+            if int(action.get("process_outputs_as_sources", False)):
+                extra_sources += outputs
+
+            # Prepare the actual command.
+            command = gyp.common.EncodePOSIXShellList(action["action"])
+            if "message" in action:
+                quiet_cmd = "Gyp action: %s ($@)" % action["message"]
+            else:
+                quiet_cmd = "Gyp action: %s ($@)" % name
+            if len(dirs) > 0:
+                command = "mkdir -p %s" % " ".join(dirs) + "; " + command
+
+            cd_action = "cd $(gyp_local_path)/%s; " % self.path
+            command = cd_action + command
+
+            # The makefile rules are all relative to the top dir, but the gyp actions
+            # are defined relative to their containing dir.  This replaces the gyp_*
+            # variables for the action rule with an absolute version so that the
+            # output goes in the right place.
+            # Only write the gyp_* rules for the "primary" output (:1);
+            # it's superfluous for the "extra outputs", and this avoids accidentally
+            # writing duplicate dummy rules for those outputs.
+            main_output = make.QuoteSpaces(self.LocalPathify(outputs[0]))
+            self.WriteLn("%s: gyp_local_path := $(LOCAL_PATH)" % main_output)
+            self.WriteLn("%s: gyp_var_prefix := $(GYP_VAR_PREFIX)" % main_output)
+            self.WriteLn(
+                "%s: gyp_intermediate_dir := "
+                "$(abspath $(gyp_intermediate_dir))" % main_output
+            )
+            self.WriteLn(
+                "%s: gyp_shared_intermediate_dir := "
+                "$(abspath $(gyp_shared_intermediate_dir))" % main_output
+            )
+
+            # Android's envsetup.sh adds a number of directories to the path including
+            # the built host binary directory. This causes actions/rules invoked by
+            # gyp to sometimes use these instead of system versions, e.g. bison.
+            # The built host binaries may not be suitable, and can cause errors.
+            # So, we remove them from the PATH using the ANDROID_BUILD_PATHS variable
+            # set by envsetup.
+            self.WriteLn(
+                "%s: export PATH := $(subst $(ANDROID_BUILD_PATHS),,$(PATH))"
+                % main_output
+            )
+
+            # Don't allow spaces in input/output filenames, but make an exception for
+            # filenames which start with '$(' since it's okay for there to be spaces
+            # inside of make function/macro invocations.
+            for input in inputs:
+                if not input.startswith("$(") and " " in input:
+                    raise gyp.common.GypError(
+                        'Action input filename "%s" in target %s contains a space'
+                        % (input, self.target)
+                    )
+            for output in outputs:
+                if not output.startswith("$(") and " " in output:
+                    raise gyp.common.GypError(
+                        'Action output filename "%s" in target %s contains a space'
+                        % (output, self.target)
+                    )
+
+            self.WriteLn(
+                "%s: %s $(GYP_TARGET_DEPENDENCIES)"
+                % (main_output, " ".join(map(self.LocalPathify, inputs)))
+            )
+            self.WriteLn('\t@echo "%s"' % quiet_cmd)
+            self.WriteLn("\t$(hide)%s\n" % command)
+            for output in outputs[1:]:
+                # Make each output depend on the main output, with an empty command
+                # to force make to notice that the mtime has changed.
+                self.WriteLn(f"{self.LocalPathify(output)}: {main_output} ;")
+
+            extra_outputs += outputs
+            self.WriteLn()
+
+        self.WriteLn()
+
+    def WriteRules(self, rules, extra_sources, extra_outputs):
+        """Write Makefile code for any 'rules' from the gyp input.
+
+        extra_sources: a list that will be filled in with newly generated source
+                       files, if any
+        extra_outputs: a list that will be filled in with any outputs of these
+                       rules (used to make other pieces dependent on these rules)
+        """
+        if len(rules) == 0:
+            return
+
+        for rule in rules:
+            if len(rule.get("rule_sources", [])) == 0:
+                continue
+            name = make.StringToMakefileVariable(
+                "{}_{}".format(self.relative_target, rule["rule_name"])
+            )
+            self.WriteLn('\n### Generated for rule "%s":' % name)
+            self.WriteLn('# "%s":' % rule)
+
+            inputs = rule.get("inputs")
+            for rule_source in rule.get("rule_sources", []):
+                (rule_source_dirname, rule_source_basename) = os.path.split(rule_source)
+                (rule_source_root, rule_source_ext) = os.path.splitext(
+                    rule_source_basename
+                )
+
+                outputs = [
+                    self.ExpandInputRoot(out, rule_source_root, rule_source_dirname)
+                    for out in rule["outputs"]
+                ]
+
+                dirs = set()
+                for out in outputs:
+                    if not out.startswith("$"):
+                        print(
+                            "WARNING: Rule for target %s writes output to local path %s"
+                            % (self.target, out)
+                        )
+                    dir = os.path.dirname(out)
+                    if dir:
+                        dirs.add(dir)
+                extra_outputs += outputs
+                if int(rule.get("process_outputs_as_sources", False)):
+                    extra_sources.extend(outputs)
+
+                components = []
+                for component in rule["action"]:
+                    component = self.ExpandInputRoot(
+                        component, rule_source_root, rule_source_dirname
+                    )
+                    if "$(RULE_SOURCES)" in component:
+                        component = component.replace("$(RULE_SOURCES)", rule_source)
+                    components.append(component)
+
+                command = gyp.common.EncodePOSIXShellList(components)
+                cd_action = "cd $(gyp_local_path)/%s; " % self.path
+                command = cd_action + command
+                if dirs:
+                    command = "mkdir -p %s" % " ".join(dirs) + "; " + command
+
+                # We set up a rule to build the first output, and then set up
+                # a rule for each additional output to depend on the first.
+                outputs = map(self.LocalPathify, outputs)
+                main_output = outputs[0]
+                self.WriteLn("%s: gyp_local_path := $(LOCAL_PATH)" % main_output)
+                self.WriteLn("%s: gyp_var_prefix := $(GYP_VAR_PREFIX)" % main_output)
+                self.WriteLn(
+                    "%s: gyp_intermediate_dir := "
+                    "$(abspath $(gyp_intermediate_dir))" % main_output
+                )
+                self.WriteLn(
+                    "%s: gyp_shared_intermediate_dir := "
+                    "$(abspath $(gyp_shared_intermediate_dir))" % main_output
+                )
+
+                # See explanation in WriteActions.
+                self.WriteLn(
+                    "%s: export PATH := "
+                    "$(subst $(ANDROID_BUILD_PATHS),,$(PATH))" % main_output
+                )
+
+                main_output_deps = self.LocalPathify(rule_source)
+                if inputs:
+                    main_output_deps += " "
+                    main_output_deps += " ".join([self.LocalPathify(f) for f in inputs])
+
+                self.WriteLn(
+                    "%s: %s $(GYP_TARGET_DEPENDENCIES)"
+                    % (main_output, main_output_deps)
+                )
+                self.WriteLn("\t%s\n" % command)
+                for output in outputs[1:]:
+                    # Make each output depend on the main output, with an empty command
+                    # to force make to notice that the mtime has changed.
+                    self.WriteLn(f"{output}: {main_output} ;")
+                self.WriteLn()
+
+        self.WriteLn()
+
+    def WriteCopies(self, copies, extra_outputs):
+        """Write Makefile code for any 'copies' from the gyp input.
+
+        extra_outputs: a list that will be filled in with any outputs of this action
+                       (used to make other pieces dependent on this action)
+        """
+        self.WriteLn("### Generated for copy rule.")
+
+        variable = make.StringToMakefileVariable(self.relative_target + "_copies")
+        outputs = []
+        for copy in copies:
+            for path in copy["files"]:
+                # The Android build system does not allow generation of files into the
+                # source tree. The destination should start with a variable, which will
+                # typically be $(gyp_intermediate_dir) or
+                # $(gyp_shared_intermediate_dir). Note that we can't use an assertion
+                # because some of the gyp tests depend on this.
+                if not copy["destination"].startswith("$"):
+                    print(
+                        "WARNING: Copy rule for target %s writes output to "
+                        "local path %s" % (self.target, copy["destination"])
+                    )
+
+                # LocalPathify() calls normpath, stripping trailing slashes.
+                path = Sourceify(self.LocalPathify(path))
+                filename = os.path.split(path)[1]
+                output = Sourceify(
+                    self.LocalPathify(os.path.join(copy["destination"], filename))
+                )
+
+                self.WriteLn(f"{output}: {path} $(GYP_TARGET_DEPENDENCIES) | $(ACP)")
+                self.WriteLn("\t@echo Copying: $@")
+                self.WriteLn("\t$(hide) mkdir -p $(dir $@)")
+                self.WriteLn("\t$(hide) $(ACP) -rpf $< $@")
+                self.WriteLn()
+                outputs.append(output)
+        self.WriteLn(
+            "{} = {}".format(variable, " ".join(map(make.QuoteSpaces, outputs)))
+        )
+        extra_outputs.append("$(%s)" % variable)
+        self.WriteLn()
+
+    def WriteSourceFlags(self, spec, configs):
+        """Write out the flags and include paths used to compile source files for
+        the current target.
+
+        Args:
+          spec, configs: input from gyp.
+        """
+        for configname, config in sorted(configs.items()):
+            extracted_includes = []
+
+            self.WriteLn("\n# Flags passed to both C and C++ files.")
+            cflags, includes_from_cflags = self.ExtractIncludesFromCFlags(
+                config.get("cflags", []) + config.get("cflags_c", [])
+            )
+            extracted_includes.extend(includes_from_cflags)
+            self.WriteList(cflags, "MY_CFLAGS_%s" % configname)
+
+            self.WriteList(
+                config.get("defines"),
+                "MY_DEFS_%s" % configname,
+                prefix="-D",
+                quoter=make.EscapeCppDefine,
+            )
+
+            self.WriteLn("\n# Include paths placed before CFLAGS/CPPFLAGS")
+            includes = list(config.get("include_dirs", []))
+            includes.extend(extracted_includes)
+            includes = map(Sourceify, map(self.LocalPathify, includes))
+            includes = self.NormalizeIncludePaths(includes)
+            self.WriteList(includes, "LOCAL_C_INCLUDES_%s" % configname)
+
+            self.WriteLn("\n# Flags passed to only C++ (and not C) files.")
+            self.WriteList(config.get("cflags_cc"), "LOCAL_CPPFLAGS_%s" % configname)
+
+        self.WriteLn(
+            "\nLOCAL_CFLAGS := $(MY_CFLAGS_$(GYP_CONFIGURATION)) "
+            "$(MY_DEFS_$(GYP_CONFIGURATION))"
+        )
+        # Undefine ANDROID for host modules
+        # TODO: the source code should not use macro ANDROID to tell if it's host
+        # or target module.
+        if self.toolset == "host":
+            self.WriteLn("# Undefine ANDROID for host modules")
+            self.WriteLn("LOCAL_CFLAGS += -UANDROID")
+        self.WriteLn(
+            "LOCAL_C_INCLUDES := $(GYP_COPIED_SOURCE_ORIGIN_DIRS) "
+            "$(LOCAL_C_INCLUDES_$(GYP_CONFIGURATION))"
+        )
+        self.WriteLn("LOCAL_CPPFLAGS := $(LOCAL_CPPFLAGS_$(GYP_CONFIGURATION))")
+        # Android uses separate flags for assembly file invocations, but gyp expects
+        # the same CFLAGS to be applied:
+        self.WriteLn("LOCAL_ASFLAGS := $(LOCAL_CFLAGS)")
+
+    def WriteSources(self, spec, configs, extra_sources):
+        """Write Makefile code for any 'sources' from the gyp input.
+        These are source files necessary to build the current target.
+        We need to handle shared_intermediate directory source files as
+        a special case by copying them to the intermediate directory and
+        treating them as a generated sources. Otherwise the Android build
+        rules won't pick them up.
+
+        Args:
+          spec, configs: input from gyp.
+          extra_sources: Sources generated from Actions or Rules.
+        """
+        sources = filter(make.Compilable, spec.get("sources", []))
+        generated_not_sources = [x for x in extra_sources if not make.Compilable(x)]
+        extra_sources = filter(make.Compilable, extra_sources)
+
+        # Determine and output the C++ extension used by these sources.
+        # We simply find the first C++ file and use that extension.
+        all_sources = sources + extra_sources
+        local_cpp_extension = ".cpp"
+        for source in all_sources:
+            (root, ext) = os.path.splitext(source)
+            if IsCPPExtension(ext):
+                local_cpp_extension = ext
+                break
+        if local_cpp_extension != ".cpp":
+            self.WriteLn("LOCAL_CPP_EXTENSION := %s" % local_cpp_extension)
+
+        # We need to move any non-generated sources that are coming from the
+        # shared intermediate directory out of LOCAL_SRC_FILES and put them
+        # into LOCAL_GENERATED_SOURCES. We also need to move over any C++ files
+        # that don't match our local_cpp_extension, since Android will only
+        # generate Makefile rules for a single LOCAL_CPP_EXTENSION.
+        local_files = []
+        for source in sources:
+            (root, ext) = os.path.splitext(source)
+            if "$(gyp_shared_intermediate_dir)" in source:
+                extra_sources.append(source)
+            elif "$(gyp_intermediate_dir)" in source:
+                extra_sources.append(source)
+            elif IsCPPExtension(ext) and ext != local_cpp_extension:
+                extra_sources.append(source)
+            else:
+                local_files.append(os.path.normpath(os.path.join(self.path, source)))
+
+        # For any generated source, if it is coming from the shared intermediate
+        # directory then we add a Make rule to copy them to the local intermediate
+        # directory first. This is because the Android LOCAL_GENERATED_SOURCES
+        # must be in the local module intermediate directory for the compile rules
+        # to work properly. If the file has the wrong C++ extension, then we add
+        # a rule to copy that to intermediates and use the new version.
+        final_generated_sources = []
+        # If a source file gets copied, we still need to add the original source
+        # directory as header search path, for GCC searches headers in the
+        # directory that contains the source file by default.
+        origin_src_dirs = []
+        for source in extra_sources:
+            local_file = source
+            if "$(gyp_intermediate_dir)/" not in local_file:
+                basename = os.path.basename(local_file)
+                local_file = "$(gyp_intermediate_dir)/" + basename
+            (root, ext) = os.path.splitext(local_file)
+            if IsCPPExtension(ext) and ext != local_cpp_extension:
+                local_file = root + local_cpp_extension
+            if local_file != source:
+                self.WriteLn(f"{local_file}: {self.LocalPathify(source)}")
+                self.WriteLn("\tmkdir -p $(@D); cp $< $@")
+                origin_src_dirs.append(os.path.dirname(source))
+            final_generated_sources.append(local_file)
+
+        # We add back in all of the non-compilable stuff to make sure that the
+        # make rules have dependencies on them.
+        final_generated_sources.extend(generated_not_sources)
+        self.WriteList(final_generated_sources, "LOCAL_GENERATED_SOURCES")
+
+        origin_src_dirs = gyp.common.uniquer(origin_src_dirs)
+        origin_src_dirs = map(Sourceify, map(self.LocalPathify, origin_src_dirs))
+        self.WriteList(origin_src_dirs, "GYP_COPIED_SOURCE_ORIGIN_DIRS")
+
+        self.WriteList(local_files, "LOCAL_SRC_FILES")
+
+        # Write out the flags used to compile the source; this must be done last
+        # so that GYP_COPIED_SOURCE_ORIGIN_DIRS can be used as an include path.
+        self.WriteSourceFlags(spec, configs)
+
+    def ComputeAndroidModule(self, spec):
+        """Return the Android module name used for a gyp spec.
+
+        We use the complete qualified target name to avoid collisions between
+        duplicate targets in different directories. We also add a suffix to
+        distinguish gyp-generated module names.
+        """
+
+        if int(spec.get("android_unmangled_name", 0)):
+            assert self.type != "shared_library" or self.target.startswith("lib")
+            return self.target
+
+        if self.type == "shared_library":
+            # For reasons of convention, the Android build system requires that all
+            # shared library modules are named 'libfoo' when generating -l flags.
+            prefix = "lib_"
+        else:
+            prefix = ""
+
+        if spec["toolset"] == "host":
+            suffix = "_$(TARGET_$(GYP_VAR_PREFIX)ARCH)_host_gyp"
+        else:
+            suffix = "_gyp"
+
+        if self.path:
+            middle = make.StringToMakefileVariable(f"{self.path}_{self.target}")
+        else:
+            middle = make.StringToMakefileVariable(self.target)
+
+        return "".join([prefix, middle, suffix])
+
+    def ComputeOutputParts(self, spec):
+        """Return the 'output basename' of a gyp spec, split into filename + ext.
+
+        Android libraries must be named the same thing as their module name,
+        otherwise the linker can't find them, so product_name and so on must be
+        ignored if we are building a library, and the "lib" prepending is
+        not done for Android.
+        """
+        assert self.type != "loadable_module"  # TODO: not supported?
+
+        target = spec["target_name"]
+        target_prefix = ""
+        target_ext = ""
+        if self.type == "static_library":
+            target = self.ComputeAndroidModule(spec)
+            target_ext = ".a"
+        elif self.type == "shared_library":
+            target = self.ComputeAndroidModule(spec)
+            target_ext = ".so"
+        elif self.type == "none":
+            target_ext = ".stamp"
+        elif self.type != "executable":
+            print(
+                "ERROR: What output file should be generated?",
+                "type",
+                self.type,
+                "target",
+                target,
+            )
+
+        if self.type != "static_library" and self.type != "shared_library":
+            target_prefix = spec.get("product_prefix", target_prefix)
+            target = spec.get("product_name", target)
+            product_ext = spec.get("product_extension")
+            if product_ext:
+                target_ext = "." + product_ext
+
+        target_stem = target_prefix + target
+        return (target_stem, target_ext)
+
+    def ComputeOutputBasename(self, spec):
+        """Return the 'output basename' of a gyp spec.
+
+        E.g., the loadable module 'foobar' in directory 'baz' will produce
+          'libfoobar.so'
+        """
+        return "".join(self.ComputeOutputParts(spec))
+
+    def ComputeOutput(self, spec):
+        """Return the 'output' (full output path) of a gyp spec.
+
+        E.g., the loadable module 'foobar' in directory 'baz' will produce
+          '$(obj)/baz/libfoobar.so'
+        """
+        if self.type == "executable":
+            # We install host executables into shared_intermediate_dir so they can be
+            # run by gyp rules that refer to PRODUCT_DIR.
+            path = "$(gyp_shared_intermediate_dir)"
+        elif self.type == "shared_library":
+            if self.toolset == "host":
+                path = "$($(GYP_HOST_VAR_PREFIX)HOST_OUT_INTERMEDIATE_LIBRARIES)"
+            else:
+                path = "$($(GYP_VAR_PREFIX)TARGET_OUT_INTERMEDIATE_LIBRARIES)"
+        else:
+            # Other targets just get built into their intermediate dir.
+            if self.toolset == "host":
+                path = (
+                    "$(call intermediates-dir-for,%s,%s,true,,"
+                    "$(GYP_HOST_VAR_PREFIX))"
+                    % (self.android_class, self.android_module)
+                )
+            else:
+                path = "$(call intermediates-dir-for,{},{},,,$(GYP_VAR_PREFIX))".format(
+                    self.android_class,
+                    self.android_module,
+                )
+
+        assert spec.get("product_dir") is None  # TODO: not supported?
+        return os.path.join(path, self.ComputeOutputBasename(spec))
+
+    def NormalizeIncludePaths(self, include_paths):
+        """Normalize include_paths.
+        Convert absolute paths to relative to the Android top directory.
+
+        Args:
+          include_paths: A list of unprocessed include paths.
+        Returns:
+          A list of normalized include paths.
+        """
+        normalized = []
+        for path in include_paths:
+            if path[0] == "/":
+                path = gyp.common.RelativePath(path, self.android_top_dir)
+            normalized.append(path)
+        return normalized
+
+    def ExtractIncludesFromCFlags(self, cflags):
+        """Extract includes "-I..." out from cflags
+
+        Args:
+          cflags: A list of compiler flags, which may be mixed with "-I.."
+        Returns:
+          A tuple of lists: (clean_clfags, include_paths). "-I.." is trimmed.
+        """
+        clean_cflags = []
+        include_paths = []
+        for flag in cflags:
+            if flag.startswith("-I"):
+                include_paths.append(flag[2:])
+            else:
+                clean_cflags.append(flag)
+
+        return (clean_cflags, include_paths)
+
+    def FilterLibraries(self, libraries):
+        """Filter the 'libraries' key to separate things that shouldn't be ldflags.
+
+        Library entries that look like filenames should be converted to android
+        module names instead of being passed to the linker as flags.
+
+        Args:
+          libraries: the value of spec.get('libraries')
+        Returns:
+          A tuple (static_lib_modules, dynamic_lib_modules, ldflags)
+        """
+        static_lib_modules = []
+        dynamic_lib_modules = []
+        ldflags = []
+        for libs in libraries:
+            # Libs can have multiple words.
+            for lib in libs.split():
+                # Filter the system libraries, which are added by default by the Android
+                # build system.
+                if (
+                    lib == "-lc"
+                    or lib == "-lstdc++"
+                    or lib == "-lm"
+                    or lib.endswith("libgcc.a")
+                ):
+                    continue
+                match = re.search(r"([^/]+)\.a$", lib)
+                if match:
+                    static_lib_modules.append(match.group(1))
+                    continue
+                match = re.search(r"([^/]+)\.so$", lib)
+                if match:
+                    dynamic_lib_modules.append(match.group(1))
+                    continue
+                if lib.startswith("-l"):
+                    ldflags.append(lib)
+        return (static_lib_modules, dynamic_lib_modules, ldflags)
+
+    def ComputeDeps(self, spec):
+        """Compute the dependencies of a gyp spec.
+
+        Returns a tuple (deps, link_deps), where each is a list of
+        filenames that will need to be put in front of make for either
+        building (deps) or linking (link_deps).
+        """
+        deps = []
+        link_deps = []
+        if "dependencies" in spec:
+            deps.extend(
+                [
+                    target_outputs[dep]
+                    for dep in spec["dependencies"]
+                    if target_outputs[dep]
+                ]
+            )
+            for dep in spec["dependencies"]:
+                if dep in target_link_deps:
+                    link_deps.append(target_link_deps[dep])
+            deps.extend(link_deps)
+        return (gyp.common.uniquer(deps), gyp.common.uniquer(link_deps))
+
+    def WriteTargetFlags(self, spec, configs, link_deps):
+        """Write Makefile code to specify the link flags and library dependencies.
+
+        spec, configs: input from gyp.
+        link_deps: link dependency list; see ComputeDeps()
+        """
+        # Libraries (i.e. -lfoo)
+        # These must be included even for static libraries as some of them provide
+        # implicit include paths through the build system.
+        libraries = gyp.common.uniquer(spec.get("libraries", []))
+        static_libs, dynamic_libs, ldflags_libs = self.FilterLibraries(libraries)
+
+        if self.type != "static_library":
+            for configname, config in sorted(configs.items()):
+                ldflags = list(config.get("ldflags", []))
+                self.WriteLn("")
+                self.WriteList(ldflags, "LOCAL_LDFLAGS_%s" % configname)
+            self.WriteList(ldflags_libs, "LOCAL_GYP_LIBS")
+            self.WriteLn(
+                "LOCAL_LDFLAGS := $(LOCAL_LDFLAGS_$(GYP_CONFIGURATION)) "
+                "$(LOCAL_GYP_LIBS)"
+            )
+
+        # Link dependencies (i.e. other gyp targets this target depends on)
+        # These need not be included for static libraries as within the gyp build
+        # we do not use the implicit include path mechanism.
+        if self.type != "static_library":
+            static_link_deps = [x[1] for x in link_deps if x[0] == "static"]
+            shared_link_deps = [x[1] for x in link_deps if x[0] == "shared"]
+        else:
+            static_link_deps = []
+            shared_link_deps = []
+
+        # Only write the lists if they are non-empty.
+        if static_libs or static_link_deps:
+            self.WriteLn("")
+            self.WriteList(static_libs + static_link_deps, "LOCAL_STATIC_LIBRARIES")
+            self.WriteLn("# Enable grouping to fix circular references")
+            self.WriteLn("LOCAL_GROUP_STATIC_LIBRARIES := true")
+        if dynamic_libs or shared_link_deps:
+            self.WriteLn("")
+            self.WriteList(dynamic_libs + shared_link_deps, "LOCAL_SHARED_LIBRARIES")
+
+    def WriteTarget(
+        self, spec, configs, deps, link_deps, part_of_all, write_alias_target
+    ):
+        """Write Makefile code to produce the final target of the gyp spec.
+
+        spec, configs: input from gyp.
+        deps, link_deps: dependency lists; see ComputeDeps()
+        part_of_all: flag indicating this target is part of 'all'
+        write_alias_target: flag indicating whether to create short aliases for this
+                            target
+        """
+        self.WriteLn("### Rules for final target.")
+
+        if self.type != "none":
+            self.WriteTargetFlags(spec, configs, link_deps)
+
+        settings = spec.get("aosp_build_settings", {})
+        if settings:
+            self.WriteLn("### Set directly by aosp_build_settings.")
+            for k, v in settings.items():
+                if isinstance(v, list):
+                    self.WriteList(v, k)
+                else:
+                    self.WriteLn(f"{k} := {make.QuoteIfNecessary(v)}")
+            self.WriteLn("")
+
+        # Add to the set of targets which represent the gyp 'all' target. We use the
+        # name 'gyp_all_modules' as the Android build system doesn't allow the use
+        # of the Make target 'all' and because 'all_modules' is the equivalent of
+        # the Make target 'all' on Android.
+        if part_of_all and write_alias_target:
+            self.WriteLn('# Add target alias to "gyp_all_modules" target.')
+            self.WriteLn(".PHONY: gyp_all_modules")
+            self.WriteLn("gyp_all_modules: %s" % self.android_module)
+            self.WriteLn("")
+
+        # Add an alias from the gyp target name to the Android module name. This
+        # simplifies manual builds of the target, and is required by the test
+        # framework.
+        if self.target != self.android_module and write_alias_target:
+            self.WriteLn("# Alias gyp target name.")
+            self.WriteLn(".PHONY: %s" % self.target)
+            self.WriteLn(f"{self.target}: {self.android_module}")
+            self.WriteLn("")
+
+        # Add the command to trigger build of the target type depending
+        # on the toolset. Ex: BUILD_STATIC_LIBRARY vs. BUILD_HOST_STATIC_LIBRARY
+        # NOTE: This has to come last!
+        modifier = ""
+        if self.toolset == "host":
+            modifier = "HOST_"
+        if self.type == "static_library":
+            self.WriteLn("include $(BUILD_%sSTATIC_LIBRARY)" % modifier)
+        elif self.type == "shared_library":
+            self.WriteLn("LOCAL_PRELINK_MODULE := false")
+            self.WriteLn("include $(BUILD_%sSHARED_LIBRARY)" % modifier)
+        elif self.type == "executable":
+            self.WriteLn("LOCAL_CXX_STL := libc++_static")
+            # Executables are for build and test purposes only, so they're installed
+            # to a directory that doesn't get included in the system image.
+            self.WriteLn("LOCAL_MODULE_PATH := $(gyp_shared_intermediate_dir)")
+            self.WriteLn("include $(BUILD_%sEXECUTABLE)" % modifier)
+        else:
+            self.WriteLn("LOCAL_MODULE_PATH := $(PRODUCT_OUT)/gyp_stamp")
+            self.WriteLn("LOCAL_UNINSTALLABLE_MODULE := true")
+            if self.toolset == "target":
+                self.WriteLn("LOCAL_2ND_ARCH_VAR_PREFIX := $(GYP_VAR_PREFIX)")
+            else:
+                self.WriteLn("LOCAL_2ND_ARCH_VAR_PREFIX := $(GYP_HOST_VAR_PREFIX)")
+            self.WriteLn()
+            self.WriteLn("include $(BUILD_SYSTEM)/base_rules.mk")
+            self.WriteLn()
+            self.WriteLn("$(LOCAL_BUILT_MODULE): $(LOCAL_ADDITIONAL_DEPENDENCIES)")
+            self.WriteLn('\t$(hide) echo "Gyp timestamp: $@"')
+            self.WriteLn("\t$(hide) mkdir -p $(dir $@)")
+            self.WriteLn("\t$(hide) touch $@")
+            self.WriteLn()
+            self.WriteLn("LOCAL_2ND_ARCH_VAR_PREFIX :=")
+
+    def WriteList(
+        self,
+        value_list,
+        variable=None,
+        prefix="",
+        quoter=make.QuoteIfNecessary,
+        local_pathify=False,
+    ):
+        """Write a variable definition that is a list of values.
+
+        E.g. WriteList(['a','b'], 'foo', prefix='blah') writes out
+             foo = blaha blahb
+        but in a pretty-printed style.
+        """
+        values = ""
+        if value_list:
+            value_list = [quoter(prefix + value) for value in value_list]
+            if local_pathify:
+                value_list = [self.LocalPathify(value) for value in value_list]
+            values = " \\\n\t" + " \\\n\t".join(value_list)
+        self.fp.write(f"{variable} :={values}\n\n")
+
+    def WriteLn(self, text=""):
+        self.fp.write(text + "\n")
+
+    def LocalPathify(self, path):
+        """Convert a subdirectory-relative path into a normalized path which starts
+        with the make variable $(LOCAL_PATH) (i.e. the top of the project tree).
+        Absolute paths, or paths that contain variables, are just normalized."""
+        if "$(" in path or os.path.isabs(path):
+            # path is not a file in the project tree in this case, but calling
+            # normpath is still important for trimming trailing slashes.
+            return os.path.normpath(path)
+        local_path = os.path.join("$(LOCAL_PATH)", self.path, path)
+        local_path = os.path.normpath(local_path)
+        # Check that normalizing the path didn't ../ itself out of $(LOCAL_PATH)
+        # - i.e. that the resulting path is still inside the project tree. The
+        # path may legitimately have ended up containing just $(LOCAL_PATH), though,
+        # so we don't look for a slash.
+        assert local_path.startswith(
+            "$(LOCAL_PATH)"
+        ), f"Path {path} attempts to escape from gyp path {self.path} !)"
+        return local_path
+
+    def ExpandInputRoot(self, template, expansion, dirname):
+        if "%(INPUT_ROOT)s" not in template and "%(INPUT_DIRNAME)s" not in template:
+            return template
+        path = template % {
+            "INPUT_ROOT": expansion,
+            "INPUT_DIRNAME": dirname,
+        }
+        return os.path.normpath(path)
+
+
+def PerformBuild(data, configurations, params):
+    # The android backend only supports the default configuration.
+    options = params["options"]
+    makefile = os.path.abspath(os.path.join(options.toplevel_dir, "GypAndroid.mk"))
+    env = dict(os.environ)
+    env["ONE_SHOT_MAKEFILE"] = makefile
+    arguments = ["make", "-C", os.environ["ANDROID_BUILD_TOP"], "gyp_all_modules"]
+    print("Building: %s" % arguments)
+    subprocess.check_call(arguments, env=env)
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    options = params["options"]
+    generator_flags = params.get("generator_flags", {})
+    limit_to_target_all = generator_flags.get("limit_to_target_all", False)
+    write_alias_targets = generator_flags.get("write_alias_targets", True)
+    sdk_version = generator_flags.get("aosp_sdk_version", 0)
+    android_top_dir = os.environ.get("ANDROID_BUILD_TOP")
+    assert android_top_dir, "$ANDROID_BUILD_TOP not set; you need to run lunch."
+
+    def CalculateMakefilePath(build_file, base_name):
+        """Determine where to write a Makefile for a given gyp file."""
+        # Paths in gyp files are relative to the .gyp file, but we want
+        # paths relative to the source root for the master makefile.  Grab
+        # the path of the .gyp file as the base to relativize against.
+        # E.g. "foo/bar" when we're constructing targets for "foo/bar/baz.gyp".
+        base_path = gyp.common.RelativePath(os.path.dirname(build_file), options.depth)
+        # We write the file in the base_path directory.
+        output_file = os.path.join(options.depth, base_path, base_name)
+        assert (
+            not options.generator_output
+        ), "The Android backend does not support options.generator_output."
+        base_path = gyp.common.RelativePath(
+            os.path.dirname(build_file), options.toplevel_dir
+        )
+        return base_path, output_file
+
+    # TODO:  search for the first non-'Default' target.  This can go
+    # away when we add verification that all targets have the
+    # necessary configurations.
+    default_configuration = None
+    for target in target_list:
+        spec = target_dicts[target]
+        if spec["default_configuration"] != "Default":
+            default_configuration = spec["default_configuration"]
+            break
+    if not default_configuration:
+        default_configuration = "Default"
+
+    makefile_name = "GypAndroid" + options.suffix + ".mk"
+    makefile_path = os.path.join(options.toplevel_dir, makefile_name)
+    assert (
+        not options.generator_output
+    ), "The Android backend does not support options.generator_output."
+    gyp.common.EnsureDirExists(makefile_path)
+    root_makefile = open(makefile_path, "w")
+
+    root_makefile.write(header)
+
+    # We set LOCAL_PATH just once, here, to the top of the project tree. This
+    # allows all the other paths we use to be relative to the Android.mk file,
+    # as the Android build system expects.
+    root_makefile.write("\nLOCAL_PATH := $(call my-dir)\n")
+
+    # Find the list of targets that derive from the gyp file(s) being built.
+    needed_targets = set()
+    for build_file in params["build_files"]:
+        for target in gyp.common.AllTargets(target_list, target_dicts, build_file):
+            needed_targets.add(target)
+
+    build_files = set()
+    include_list = set()
+    android_modules = {}
+    for qualified_target in target_list:
+        build_file, target, toolset = gyp.common.ParseQualifiedTarget(qualified_target)
+        relative_build_file = gyp.common.RelativePath(build_file, options.toplevel_dir)
+        build_files.add(relative_build_file)
+        included_files = data[build_file]["included_files"]
+        for included_file in included_files:
+            # The included_files entries are relative to the dir of the build file
+            # that included them, so we have to undo that and then make them relative
+            # to the root dir.
+            relative_include_file = gyp.common.RelativePath(
+                gyp.common.UnrelativePath(included_file, build_file),
+                options.toplevel_dir,
+            )
+            abs_include_file = os.path.abspath(relative_include_file)
+            # If the include file is from the ~/.gyp dir, we should use absolute path
+            # so that relocating the src dir doesn't break the path.
+            if params["home_dot_gyp"] and abs_include_file.startswith(
+                params["home_dot_gyp"]
+            ):
+                build_files.add(abs_include_file)
+            else:
+                build_files.add(relative_include_file)
+
+        base_path, output_file = CalculateMakefilePath(
+            build_file, target + "." + toolset + options.suffix + ".mk"
+        )
+
+        spec = target_dicts[qualified_target]
+        configs = spec["configurations"]
+
+        part_of_all = qualified_target in needed_targets
+        if limit_to_target_all and not part_of_all:
+            continue
+
+        relative_target = gyp.common.QualifiedTarget(
+            relative_build_file, target, toolset
+        )
+        writer = AndroidMkWriter(android_top_dir)
+        android_module = writer.Write(
+            qualified_target,
+            relative_target,
+            base_path,
+            output_file,
+            spec,
+            configs,
+            part_of_all=part_of_all,
+            write_alias_target=write_alias_targets,
+            sdk_version=sdk_version,
+        )
+        if android_module in android_modules:
+            print(
+                "ERROR: Android module names must be unique. The following "
+                "targets both generate Android module name %s.\n  %s\n  %s"
+                % (android_module, android_modules[android_module], qualified_target)
+            )
+            return
+        android_modules[android_module] = qualified_target
+
+        # Our root_makefile lives at the source root.  Compute the relative path
+        # from there to the output_file for including.
+        mkfile_rel_path = gyp.common.RelativePath(
+            output_file, os.path.dirname(makefile_path)
+        )
+        include_list.add(mkfile_rel_path)
+
+    root_makefile.write("GYP_CONFIGURATION ?= %s\n" % default_configuration)
+    root_makefile.write("GYP_VAR_PREFIX ?=\n")
+    root_makefile.write("GYP_HOST_VAR_PREFIX ?=\n")
+    root_makefile.write("GYP_HOST_MULTILIB ?= first\n")
+
+    # Write out the sorted list of includes.
+    root_makefile.write("\n")
+    for include_file in sorted(include_list):
+        root_makefile.write("include $(LOCAL_PATH)/" + include_file + "\n")
+    root_makefile.write("\n")
+
+    if write_alias_targets:
+        root_makefile.write(ALL_MODULES_FOOTER)
+
+    root_makefile.close()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/cmake.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/cmake.py
new file mode 100644
index 0000000..c95d184
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/cmake.py
@@ -0,0 +1,1321 @@
+# Copyright (c) 2013 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""cmake output module
+
+This module is under development and should be considered experimental.
+
+This module produces cmake (2.8.8+) input as its output. One CMakeLists.txt is
+created for each configuration.
+
+This module's original purpose was to support editing in IDEs like KDevelop
+which use CMake for project management. It is also possible to use CMake to
+generate projects for other IDEs such as eclipse cdt and code::blocks. QtCreator
+will convert the CMakeLists.txt to a code::blocks cbp for the editor to read,
+but build using CMake. As a result QtCreator editor is unaware of compiler
+defines. The generated CMakeLists.txt can also be used to build on Linux. There
+is currently no support for building on platforms other than Linux.
+
+The generated CMakeLists.txt should properly compile all projects. However,
+there is a mismatch between gyp and cmake with regard to linking. All attempts
+are made to work around this, but CMake sometimes sees -Wl,--start-group as a
+library and incorrectly repeats it. As a result the output of this generator
+should not be relied on for building.
+
+When using with kdevelop, use version 4.4+. Previous versions of kdevelop will
+not be able to find the header file directories described in the generated
+CMakeLists.txt file.
+"""
+
+
+import multiprocessing
+import os
+import signal
+import subprocess
+import gyp.common
+import gyp.xcode_emulation
+
+_maketrans = str.maketrans
+
+generator_default_variables = {
+    "EXECUTABLE_PREFIX": "",
+    "EXECUTABLE_SUFFIX": "",
+    "STATIC_LIB_PREFIX": "lib",
+    "STATIC_LIB_SUFFIX": ".a",
+    "SHARED_LIB_PREFIX": "lib",
+    "SHARED_LIB_SUFFIX": ".so",
+    "SHARED_LIB_DIR": "${builddir}/lib.${TOOLSET}",
+    "LIB_DIR": "${obj}.${TOOLSET}",
+    "INTERMEDIATE_DIR": "${obj}.${TOOLSET}/${TARGET}/geni",
+    "SHARED_INTERMEDIATE_DIR": "${obj}/gen",
+    "PRODUCT_DIR": "${builddir}",
+    "RULE_INPUT_PATH": "${RULE_INPUT_PATH}",
+    "RULE_INPUT_DIRNAME": "${RULE_INPUT_DIRNAME}",
+    "RULE_INPUT_NAME": "${RULE_INPUT_NAME}",
+    "RULE_INPUT_ROOT": "${RULE_INPUT_ROOT}",
+    "RULE_INPUT_EXT": "${RULE_INPUT_EXT}",
+    "CONFIGURATION_NAME": "${configuration}",
+}
+
+FULL_PATH_VARS = ("${CMAKE_CURRENT_LIST_DIR}", "${builddir}", "${obj}")
+
+generator_supports_multiple_toolsets = True
+generator_wants_static_library_dependencies_adjusted = True
+
+COMPILABLE_EXTENSIONS = {
+    ".c": "cc",
+    ".cc": "cxx",
+    ".cpp": "cxx",
+    ".cxx": "cxx",
+    ".s": "s",  # cc
+    ".S": "s",  # cc
+}
+
+
+def RemovePrefix(a, prefix):
+    """Returns 'a' without 'prefix' if it starts with 'prefix'."""
+    return a[len(prefix) :] if a.startswith(prefix) else a
+
+
+def CalculateVariables(default_variables, params):
+    """Calculate additional variables for use in the build (called by gyp)."""
+    default_variables.setdefault("OS", gyp.common.GetFlavor(params))
+
+
+def Compilable(filename):
+    """Return true if the file is compilable (should be in OBJS)."""
+    return any(filename.endswith(e) for e in COMPILABLE_EXTENSIONS)
+
+
+def Linkable(filename):
+    """Return true if the file is linkable (should be on the link line)."""
+    return filename.endswith(".o")
+
+
+def NormjoinPathForceCMakeSource(base_path, rel_path):
+    """Resolves rel_path against base_path and returns the result.
+
+  If rel_path is an absolute path it is returned unchanged.
+  Otherwise it is resolved against base_path and normalized.
+  If the result is a relative path, it is forced to be relative to the
+  CMakeLists.txt.
+  """
+    if os.path.isabs(rel_path):
+        return rel_path
+    if any([rel_path.startswith(var) for var in FULL_PATH_VARS]):
+        return rel_path
+    # TODO: do we need to check base_path for absolute variables as well?
+    return os.path.join(
+        "${CMAKE_CURRENT_LIST_DIR}", os.path.normpath(os.path.join(base_path, rel_path))
+    )
+
+
+def NormjoinPath(base_path, rel_path):
+    """Resolves rel_path against base_path and returns the result.
+  TODO: what is this really used for?
+  If rel_path begins with '$' it is returned unchanged.
+  Otherwise it is resolved against base_path if relative, then normalized.
+  """
+    if rel_path.startswith("$") and not rel_path.startswith("${configuration}"):
+        return rel_path
+    return os.path.normpath(os.path.join(base_path, rel_path))
+
+
+def CMakeStringEscape(a):
+    """Escapes the string 'a' for use inside a CMake string.
+
+  This means escaping
+  '\' otherwise it may be seen as modifying the next character
+  '"' otherwise it will end the string
+  ';' otherwise the string becomes a list
+
+  The following do not need to be escaped
+  '#' when the lexer is in string state, this does not start a comment
+
+  The following are yet unknown
+  '$' generator variables (like ${obj}) must not be escaped,
+      but text $ should be escaped
+      what is wanted is to know which $ come from generator variables
+  """
+    return a.replace("\\", "\\\\").replace(";", "\\;").replace('"', '\\"')
+
+
+def SetFileProperty(output, source_name, property_name, values, sep):
+    """Given a set of source file, sets the given property on them."""
+    output.write("set_source_files_properties(")
+    output.write(source_name)
+    output.write(" PROPERTIES ")
+    output.write(property_name)
+    output.write(' "')
+    for value in values:
+        output.write(CMakeStringEscape(value))
+        output.write(sep)
+    output.write('")\n')
+
+
+def SetFilesProperty(output, variable, property_name, values, sep):
+    """Given a set of source files, sets the given property on them."""
+    output.write("set_source_files_properties(")
+    WriteVariable(output, variable)
+    output.write(" PROPERTIES ")
+    output.write(property_name)
+    output.write(' "')
+    for value in values:
+        output.write(CMakeStringEscape(value))
+        output.write(sep)
+    output.write('")\n')
+
+
+def SetTargetProperty(output, target_name, property_name, values, sep=""):
+    """Given a target, sets the given property."""
+    output.write("set_target_properties(")
+    output.write(target_name)
+    output.write(" PROPERTIES ")
+    output.write(property_name)
+    output.write(' "')
+    for value in values:
+        output.write(CMakeStringEscape(value))
+        output.write(sep)
+    output.write('")\n')
+
+
+def SetVariable(output, variable_name, value):
+    """Sets a CMake variable."""
+    output.write("set(")
+    output.write(variable_name)
+    output.write(' "')
+    output.write(CMakeStringEscape(value))
+    output.write('")\n')
+
+
+def SetVariableList(output, variable_name, values):
+    """Sets a CMake variable to a list."""
+    if not values:
+        return SetVariable(output, variable_name, "")
+    if len(values) == 1:
+        return SetVariable(output, variable_name, values[0])
+    output.write("list(APPEND ")
+    output.write(variable_name)
+    output.write('\n  "')
+    output.write('"\n  "'.join([CMakeStringEscape(value) for value in values]))
+    output.write('")\n')
+
+
+def UnsetVariable(output, variable_name):
+    """Unsets a CMake variable."""
+    output.write("unset(")
+    output.write(variable_name)
+    output.write(")\n")
+
+
+def WriteVariable(output, variable_name, prepend=None):
+    if prepend:
+        output.write(prepend)
+    output.write("${")
+    output.write(variable_name)
+    output.write("}")
+
+
+class CMakeTargetType:
+    def __init__(self, command, modifier, property_modifier):
+        self.command = command
+        self.modifier = modifier
+        self.property_modifier = property_modifier
+
+
+cmake_target_type_from_gyp_target_type = {
+    "executable": CMakeTargetType("add_executable", None, "RUNTIME"),
+    "static_library": CMakeTargetType("add_library", "STATIC", "ARCHIVE"),
+    "shared_library": CMakeTargetType("add_library", "SHARED", "LIBRARY"),
+    "loadable_module": CMakeTargetType("add_library", "MODULE", "LIBRARY"),
+    "none": CMakeTargetType("add_custom_target", "SOURCES", None),
+}
+
+
+def StringToCMakeTargetName(a):
+    """Converts the given string 'a' to a valid CMake target name.
+
+  All invalid characters are replaced by '_'.
+  Invalid for cmake: ' ', '/', '(', ')', '"'
+  Invalid for make: ':'
+  Invalid for unknown reasons but cause failures: '.'
+  """
+    return a.translate(_maketrans(' /():."', "_______"))
+
+
+def WriteActions(target_name, actions, extra_sources, extra_deps, path_to_gyp, output):
+    """Write CMake for the 'actions' in the target.
+
+  Args:
+    target_name: the name of the CMake target being generated.
+    actions: the Gyp 'actions' dict for this target.
+    extra_sources: [(<cmake_src>, <src>)] to append with generated source files.
+    extra_deps: [<cmake_taget>] to append with generated targets.
+    path_to_gyp: relative path from CMakeLists.txt being generated to
+        the Gyp file in which the target being generated is defined.
+  """
+    for action in actions:
+        action_name = StringToCMakeTargetName(action["action_name"])
+        action_target_name = f"{target_name}__{action_name}"
+
+        inputs = action["inputs"]
+        inputs_name = action_target_name + "__input"
+        SetVariableList(
+            output,
+            inputs_name,
+            [NormjoinPathForceCMakeSource(path_to_gyp, dep) for dep in inputs],
+        )
+
+        outputs = action["outputs"]
+        cmake_outputs = [
+            NormjoinPathForceCMakeSource(path_to_gyp, out) for out in outputs
+        ]
+        outputs_name = action_target_name + "__output"
+        SetVariableList(output, outputs_name, cmake_outputs)
+
+        # Build up a list of outputs.
+        # Collect the output dirs we'll need.
+        dirs = {dir for dir in (os.path.dirname(o) for o in outputs) if dir}
+
+        if int(action.get("process_outputs_as_sources", False)):
+            extra_sources.extend(zip(cmake_outputs, outputs))
+
+        # add_custom_command
+        output.write("add_custom_command(OUTPUT ")
+        WriteVariable(output, outputs_name)
+        output.write("\n")
+
+        if len(dirs) > 0:
+            for directory in dirs:
+                output.write("  COMMAND ${CMAKE_COMMAND} -E make_directory ")
+                output.write(directory)
+                output.write("\n")
+
+        output.write("  COMMAND ")
+        output.write(gyp.common.EncodePOSIXShellList(action["action"]))
+        output.write("\n")
+
+        output.write("  DEPENDS ")
+        WriteVariable(output, inputs_name)
+        output.write("\n")
+
+        output.write("  WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/")
+        output.write(path_to_gyp)
+        output.write("\n")
+
+        output.write("  COMMENT ")
+        if "message" in action:
+            output.write(action["message"])
+        else:
+            output.write(action_target_name)
+        output.write("\n")
+
+        output.write("  VERBATIM\n")
+        output.write(")\n")
+
+        # add_custom_target
+        output.write("add_custom_target(")
+        output.write(action_target_name)
+        output.write("\n  DEPENDS ")
+        WriteVariable(output, outputs_name)
+        output.write("\n  SOURCES ")
+        WriteVariable(output, inputs_name)
+        output.write("\n)\n")
+
+        extra_deps.append(action_target_name)
+
+
+def NormjoinRulePathForceCMakeSource(base_path, rel_path, rule_source):
+    if rel_path.startswith(("${RULE_INPUT_PATH}", "${RULE_INPUT_DIRNAME}")):
+        if any([rule_source.startswith(var) for var in FULL_PATH_VARS]):
+            return rel_path
+    return NormjoinPathForceCMakeSource(base_path, rel_path)
+
+
+def WriteRules(target_name, rules, extra_sources, extra_deps, path_to_gyp, output):
+    """Write CMake for the 'rules' in the target.
+
+  Args:
+    target_name: the name of the CMake target being generated.
+    actions: the Gyp 'actions' dict for this target.
+    extra_sources: [(<cmake_src>, <src>)] to append with generated source files.
+    extra_deps: [<cmake_taget>] to append with generated targets.
+    path_to_gyp: relative path from CMakeLists.txt being generated to
+        the Gyp file in which the target being generated is defined.
+  """
+    for rule in rules:
+        rule_name = StringToCMakeTargetName(target_name + "__" + rule["rule_name"])
+
+        inputs = rule.get("inputs", [])
+        inputs_name = rule_name + "__input"
+        SetVariableList(
+            output,
+            inputs_name,
+            [NormjoinPathForceCMakeSource(path_to_gyp, dep) for dep in inputs],
+        )
+        outputs = rule["outputs"]
+        var_outputs = []
+
+        for count, rule_source in enumerate(rule.get("rule_sources", [])):
+            action_name = rule_name + "_" + str(count)
+
+            rule_source_dirname, rule_source_basename = os.path.split(rule_source)
+            rule_source_root, rule_source_ext = os.path.splitext(rule_source_basename)
+
+            SetVariable(output, "RULE_INPUT_PATH", rule_source)
+            SetVariable(output, "RULE_INPUT_DIRNAME", rule_source_dirname)
+            SetVariable(output, "RULE_INPUT_NAME", rule_source_basename)
+            SetVariable(output, "RULE_INPUT_ROOT", rule_source_root)
+            SetVariable(output, "RULE_INPUT_EXT", rule_source_ext)
+
+            # Build up a list of outputs.
+            # Collect the output dirs we'll need.
+            dirs = {dir for dir in (os.path.dirname(o) for o in outputs) if dir}
+
+            # Create variables for the output, as 'local' variable will be unset.
+            these_outputs = []
+            for output_index, out in enumerate(outputs):
+                output_name = action_name + "_" + str(output_index)
+                SetVariable(
+                    output,
+                    output_name,
+                    NormjoinRulePathForceCMakeSource(path_to_gyp, out, rule_source),
+                )
+                if int(rule.get("process_outputs_as_sources", False)):
+                    extra_sources.append(("${" + output_name + "}", out))
+                these_outputs.append("${" + output_name + "}")
+                var_outputs.append("${" + output_name + "}")
+
+            # add_custom_command
+            output.write("add_custom_command(OUTPUT\n")
+            for out in these_outputs:
+                output.write("  ")
+                output.write(out)
+                output.write("\n")
+
+            for directory in dirs:
+                output.write("  COMMAND ${CMAKE_COMMAND} -E make_directory ")
+                output.write(directory)
+                output.write("\n")
+
+            output.write("  COMMAND ")
+            output.write(gyp.common.EncodePOSIXShellList(rule["action"]))
+            output.write("\n")
+
+            output.write("  DEPENDS ")
+            WriteVariable(output, inputs_name)
+            output.write(" ")
+            output.write(NormjoinPath(path_to_gyp, rule_source))
+            output.write("\n")
+
+            # CMAKE_CURRENT_LIST_DIR is where the CMakeLists.txt lives.
+            # The cwd is the current build directory.
+            output.write("  WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/")
+            output.write(path_to_gyp)
+            output.write("\n")
+
+            output.write("  COMMENT ")
+            if "message" in rule:
+                output.write(rule["message"])
+            else:
+                output.write(action_name)
+            output.write("\n")
+
+            output.write("  VERBATIM\n")
+            output.write(")\n")
+
+            UnsetVariable(output, "RULE_INPUT_PATH")
+            UnsetVariable(output, "RULE_INPUT_DIRNAME")
+            UnsetVariable(output, "RULE_INPUT_NAME")
+            UnsetVariable(output, "RULE_INPUT_ROOT")
+            UnsetVariable(output, "RULE_INPUT_EXT")
+
+        # add_custom_target
+        output.write("add_custom_target(")
+        output.write(rule_name)
+        output.write(" DEPENDS\n")
+        for out in var_outputs:
+            output.write("  ")
+            output.write(out)
+            output.write("\n")
+        output.write("SOURCES ")
+        WriteVariable(output, inputs_name)
+        output.write("\n")
+        for rule_source in rule.get("rule_sources", []):
+            output.write("  ")
+            output.write(NormjoinPath(path_to_gyp, rule_source))
+            output.write("\n")
+        output.write(")\n")
+
+        extra_deps.append(rule_name)
+
+
+def WriteCopies(target_name, copies, extra_deps, path_to_gyp, output):
+    """Write CMake for the 'copies' in the target.
+
+  Args:
+    target_name: the name of the CMake target being generated.
+    actions: the Gyp 'actions' dict for this target.
+    extra_deps: [<cmake_taget>] to append with generated targets.
+    path_to_gyp: relative path from CMakeLists.txt being generated to
+        the Gyp file in which the target being generated is defined.
+  """
+    copy_name = target_name + "__copies"
+
+    # CMake gets upset with custom targets with OUTPUT which specify no output.
+    have_copies = any(copy["files"] for copy in copies)
+    if not have_copies:
+        output.write("add_custom_target(")
+        output.write(copy_name)
+        output.write(")\n")
+        extra_deps.append(copy_name)
+        return
+
+    class Copy:
+        def __init__(self, ext, command):
+            self.cmake_inputs = []
+            self.cmake_outputs = []
+            self.gyp_inputs = []
+            self.gyp_outputs = []
+            self.ext = ext
+            self.inputs_name = None
+            self.outputs_name = None
+            self.command = command
+
+    file_copy = Copy("", "copy")
+    dir_copy = Copy("_dirs", "copy_directory")
+
+    for copy in copies:
+        files = copy["files"]
+        destination = copy["destination"]
+        for src in files:
+            path = os.path.normpath(src)
+            basename = os.path.split(path)[1]
+            dst = os.path.join(destination, basename)
+
+            copy = file_copy if os.path.basename(src) else dir_copy
+
+            copy.cmake_inputs.append(NormjoinPathForceCMakeSource(path_to_gyp, src))
+            copy.cmake_outputs.append(NormjoinPathForceCMakeSource(path_to_gyp, dst))
+            copy.gyp_inputs.append(src)
+            copy.gyp_outputs.append(dst)
+
+    for copy in (file_copy, dir_copy):
+        if copy.cmake_inputs:
+            copy.inputs_name = copy_name + "__input" + copy.ext
+            SetVariableList(output, copy.inputs_name, copy.cmake_inputs)
+
+            copy.outputs_name = copy_name + "__output" + copy.ext
+            SetVariableList(output, copy.outputs_name, copy.cmake_outputs)
+
+    # add_custom_command
+    output.write("add_custom_command(\n")
+
+    output.write("OUTPUT")
+    for copy in (file_copy, dir_copy):
+        if copy.outputs_name:
+            WriteVariable(output, copy.outputs_name, " ")
+    output.write("\n")
+
+    for copy in (file_copy, dir_copy):
+        for src, dst in zip(copy.gyp_inputs, copy.gyp_outputs):
+            # 'cmake -E copy src dst' will create the 'dst' directory if needed.
+            output.write("COMMAND ${CMAKE_COMMAND} -E %s " % copy.command)
+            output.write(src)
+            output.write(" ")
+            output.write(dst)
+            output.write("\n")
+
+    output.write("DEPENDS")
+    for copy in (file_copy, dir_copy):
+        if copy.inputs_name:
+            WriteVariable(output, copy.inputs_name, " ")
+    output.write("\n")
+
+    output.write("WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/")
+    output.write(path_to_gyp)
+    output.write("\n")
+
+    output.write("COMMENT Copying for ")
+    output.write(target_name)
+    output.write("\n")
+
+    output.write("VERBATIM\n")
+    output.write(")\n")
+
+    # add_custom_target
+    output.write("add_custom_target(")
+    output.write(copy_name)
+    output.write("\n  DEPENDS")
+    for copy in (file_copy, dir_copy):
+        if copy.outputs_name:
+            WriteVariable(output, copy.outputs_name, " ")
+    output.write("\n  SOURCES")
+    if file_copy.inputs_name:
+        WriteVariable(output, file_copy.inputs_name, " ")
+    output.write("\n)\n")
+
+    extra_deps.append(copy_name)
+
+
+def CreateCMakeTargetBaseName(qualified_target):
+    """This is the name we would like the target to have."""
+    _, gyp_target_name, gyp_target_toolset = gyp.common.ParseQualifiedTarget(
+        qualified_target
+    )
+    cmake_target_base_name = gyp_target_name
+    if gyp_target_toolset and gyp_target_toolset != "target":
+        cmake_target_base_name += "_" + gyp_target_toolset
+    return StringToCMakeTargetName(cmake_target_base_name)
+
+
+def CreateCMakeTargetFullName(qualified_target):
+    """An unambiguous name for the target."""
+    gyp_file, gyp_target_name, gyp_target_toolset = gyp.common.ParseQualifiedTarget(
+        qualified_target
+    )
+    cmake_target_full_name = gyp_file + ":" + gyp_target_name
+    if gyp_target_toolset and gyp_target_toolset != "target":
+        cmake_target_full_name += "_" + gyp_target_toolset
+    return StringToCMakeTargetName(cmake_target_full_name)
+
+
+class CMakeNamer:
+    """Converts Gyp target names into CMake target names.
+
+  CMake requires that target names be globally unique. One way to ensure
+  this is to fully qualify the names of the targets. Unfortunately, this
+  ends up with all targets looking like "chrome_chrome_gyp_chrome" instead
+  of just "chrome". If this generator were only interested in building, it
+  would be possible to fully qualify all target names, then create
+  unqualified target names which depend on all qualified targets which
+  should have had that name. This is more or less what the 'make' generator
+  does with aliases. However, one goal of this generator is to create CMake
+  files for use with IDEs, and fully qualified names are not as user
+  friendly.
+
+  Since target name collision is rare, we do the above only when required.
+
+  Toolset variants are always qualified from the base, as this is required for
+  building. However, it also makes sense for an IDE, as it is possible for
+  defines to be different.
+  """
+
+    def __init__(self, target_list):
+        self.cmake_target_base_names_conficting = set()
+
+        cmake_target_base_names_seen = set()
+        for qualified_target in target_list:
+            cmake_target_base_name = CreateCMakeTargetBaseName(qualified_target)
+
+            if cmake_target_base_name not in cmake_target_base_names_seen:
+                cmake_target_base_names_seen.add(cmake_target_base_name)
+            else:
+                self.cmake_target_base_names_conficting.add(cmake_target_base_name)
+
+    def CreateCMakeTargetName(self, qualified_target):
+        base_name = CreateCMakeTargetBaseName(qualified_target)
+        if base_name in self.cmake_target_base_names_conficting:
+            return CreateCMakeTargetFullName(qualified_target)
+        return base_name
+
+
+def WriteTarget(
+    namer,
+    qualified_target,
+    target_dicts,
+    build_dir,
+    config_to_use,
+    options,
+    generator_flags,
+    all_qualified_targets,
+    flavor,
+    output,
+):
+    # The make generator does this always.
+    # TODO: It would be nice to be able to tell CMake all dependencies.
+    circular_libs = generator_flags.get("circular", True)
+
+    if not generator_flags.get("standalone", False):
+        output.write("\n#")
+        output.write(qualified_target)
+        output.write("\n")
+
+    gyp_file, _, _ = gyp.common.ParseQualifiedTarget(qualified_target)
+    rel_gyp_file = gyp.common.RelativePath(gyp_file, options.toplevel_dir)
+    rel_gyp_dir = os.path.dirname(rel_gyp_file)
+
+    # Relative path from build dir to top dir.
+    build_to_top = gyp.common.InvertRelativePath(build_dir, options.toplevel_dir)
+    # Relative path from build dir to gyp dir.
+    build_to_gyp = os.path.join(build_to_top, rel_gyp_dir)
+
+    path_from_cmakelists_to_gyp = build_to_gyp
+
+    spec = target_dicts.get(qualified_target, {})
+    config = spec.get("configurations", {}).get(config_to_use, {})
+
+    xcode_settings = None
+    if flavor == "mac":
+        xcode_settings = gyp.xcode_emulation.XcodeSettings(spec)
+
+    target_name = spec.get("target_name", "<missing target name>")
+    target_type = spec.get("type", "<missing target type>")
+    target_toolset = spec.get("toolset")
+
+    cmake_target_type = cmake_target_type_from_gyp_target_type.get(target_type)
+    if cmake_target_type is None:
+        print(
+            "Target %s has unknown target type %s, skipping."
+            % (target_name, target_type)
+        )
+        return
+
+    SetVariable(output, "TARGET", target_name)
+    SetVariable(output, "TOOLSET", target_toolset)
+
+    cmake_target_name = namer.CreateCMakeTargetName(qualified_target)
+
+    extra_sources = []
+    extra_deps = []
+
+    # Actions must come first, since they can generate more OBJs for use below.
+    if "actions" in spec:
+        WriteActions(
+            cmake_target_name,
+            spec["actions"],
+            extra_sources,
+            extra_deps,
+            path_from_cmakelists_to_gyp,
+            output,
+        )
+
+    # Rules must be early like actions.
+    if "rules" in spec:
+        WriteRules(
+            cmake_target_name,
+            spec["rules"],
+            extra_sources,
+            extra_deps,
+            path_from_cmakelists_to_gyp,
+            output,
+        )
+
+    # Copies
+    if "copies" in spec:
+        WriteCopies(
+            cmake_target_name,
+            spec["copies"],
+            extra_deps,
+            path_from_cmakelists_to_gyp,
+            output,
+        )
+
+    # Target and sources
+    srcs = spec.get("sources", [])
+
+    # Gyp separates the sheep from the goats based on file extensions.
+    # A full separation is done here because of flag handing (see below).
+    s_sources = []
+    c_sources = []
+    cxx_sources = []
+    linkable_sources = []
+    other_sources = []
+    for src in srcs:
+        _, ext = os.path.splitext(src)
+        src_type = COMPILABLE_EXTENSIONS.get(ext, None)
+        src_norm_path = NormjoinPath(path_from_cmakelists_to_gyp, src)
+
+        if src_type == "s":
+            s_sources.append(src_norm_path)
+        elif src_type == "cc":
+            c_sources.append(src_norm_path)
+        elif src_type == "cxx":
+            cxx_sources.append(src_norm_path)
+        elif Linkable(ext):
+            linkable_sources.append(src_norm_path)
+        else:
+            other_sources.append(src_norm_path)
+
+    for extra_source in extra_sources:
+        src, real_source = extra_source
+        _, ext = os.path.splitext(real_source)
+        src_type = COMPILABLE_EXTENSIONS.get(ext, None)
+
+        if src_type == "s":
+            s_sources.append(src)
+        elif src_type == "cc":
+            c_sources.append(src)
+        elif src_type == "cxx":
+            cxx_sources.append(src)
+        elif Linkable(ext):
+            linkable_sources.append(src)
+        else:
+            other_sources.append(src)
+
+    s_sources_name = None
+    if s_sources:
+        s_sources_name = cmake_target_name + "__asm_srcs"
+        SetVariableList(output, s_sources_name, s_sources)
+
+    c_sources_name = None
+    if c_sources:
+        c_sources_name = cmake_target_name + "__c_srcs"
+        SetVariableList(output, c_sources_name, c_sources)
+
+    cxx_sources_name = None
+    if cxx_sources:
+        cxx_sources_name = cmake_target_name + "__cxx_srcs"
+        SetVariableList(output, cxx_sources_name, cxx_sources)
+
+    linkable_sources_name = None
+    if linkable_sources:
+        linkable_sources_name = cmake_target_name + "__linkable_srcs"
+        SetVariableList(output, linkable_sources_name, linkable_sources)
+
+    other_sources_name = None
+    if other_sources:
+        other_sources_name = cmake_target_name + "__other_srcs"
+        SetVariableList(output, other_sources_name, other_sources)
+
+    # CMake gets upset when executable targets provide no sources.
+    # http://www.cmake.org/pipermail/cmake/2010-July/038461.html
+    dummy_sources_name = None
+    has_sources = (
+        s_sources_name
+        or c_sources_name
+        or cxx_sources_name
+        or linkable_sources_name
+        or other_sources_name
+    )
+    if target_type == "executable" and not has_sources:
+        dummy_sources_name = cmake_target_name + "__dummy_srcs"
+        SetVariable(
+            output, dummy_sources_name, "${obj}.${TOOLSET}/${TARGET}/genc/dummy.c"
+        )
+        output.write('if(NOT EXISTS "')
+        WriteVariable(output, dummy_sources_name)
+        output.write('")\n')
+        output.write('  file(WRITE "')
+        WriteVariable(output, dummy_sources_name)
+        output.write('" "")\n')
+        output.write("endif()\n")
+
+    # CMake is opposed to setting linker directories and considers the practice
+    # of setting linker directories dangerous. Instead, it favors the use of
+    # find_library and passing absolute paths to target_link_libraries.
+    # However, CMake does provide the command link_directories, which adds
+    # link directories to targets defined after it is called.
+    # As a result, link_directories must come before the target definition.
+    # CMake unfortunately has no means of removing entries from LINK_DIRECTORIES.
+    library_dirs = config.get("library_dirs")
+    if library_dirs is not None:
+        output.write("link_directories(")
+        for library_dir in library_dirs:
+            output.write(" ")
+            output.write(NormjoinPath(path_from_cmakelists_to_gyp, library_dir))
+            output.write("\n")
+        output.write(")\n")
+
+    output.write(cmake_target_type.command)
+    output.write("(")
+    output.write(cmake_target_name)
+
+    if cmake_target_type.modifier is not None:
+        output.write(" ")
+        output.write(cmake_target_type.modifier)
+
+    if s_sources_name:
+        WriteVariable(output, s_sources_name, " ")
+    if c_sources_name:
+        WriteVariable(output, c_sources_name, " ")
+    if cxx_sources_name:
+        WriteVariable(output, cxx_sources_name, " ")
+    if linkable_sources_name:
+        WriteVariable(output, linkable_sources_name, " ")
+    if other_sources_name:
+        WriteVariable(output, other_sources_name, " ")
+    if dummy_sources_name:
+        WriteVariable(output, dummy_sources_name, " ")
+
+    output.write(")\n")
+
+    # Let CMake know if the 'all' target should depend on this target.
+    exclude_from_all = (
+        "TRUE" if qualified_target not in all_qualified_targets else "FALSE"
+    )
+    SetTargetProperty(output, cmake_target_name, "EXCLUDE_FROM_ALL", exclude_from_all)
+    for extra_target_name in extra_deps:
+        SetTargetProperty(
+            output, extra_target_name, "EXCLUDE_FROM_ALL", exclude_from_all
+        )
+
+    # Output name and location.
+    if target_type != "none":
+        # Link as 'C' if there are no other files
+        if not c_sources and not cxx_sources:
+            SetTargetProperty(output, cmake_target_name, "LINKER_LANGUAGE", ["C"])
+
+        # Mark uncompiled sources as uncompiled.
+        if other_sources_name:
+            output.write("set_source_files_properties(")
+            WriteVariable(output, other_sources_name, "")
+            output.write(' PROPERTIES HEADER_FILE_ONLY "TRUE")\n')
+
+        # Mark object sources as linkable.
+        if linkable_sources_name:
+            output.write("set_source_files_properties(")
+            WriteVariable(output, other_sources_name, "")
+            output.write(' PROPERTIES EXTERNAL_OBJECT "TRUE")\n')
+
+        # Output directory
+        target_output_directory = spec.get("product_dir")
+        if target_output_directory is None:
+            if target_type in ("executable", "loadable_module"):
+                target_output_directory = generator_default_variables["PRODUCT_DIR"]
+            elif target_type == "shared_library":
+                target_output_directory = "${builddir}/lib.${TOOLSET}"
+            elif spec.get("standalone_static_library", False):
+                target_output_directory = generator_default_variables["PRODUCT_DIR"]
+            else:
+                base_path = gyp.common.RelativePath(
+                    os.path.dirname(gyp_file), options.toplevel_dir
+                )
+                target_output_directory = "${obj}.${TOOLSET}"
+                target_output_directory = os.path.join(
+                    target_output_directory, base_path
+                )
+
+        cmake_target_output_directory = NormjoinPathForceCMakeSource(
+            path_from_cmakelists_to_gyp, target_output_directory
+        )
+        SetTargetProperty(
+            output,
+            cmake_target_name,
+            cmake_target_type.property_modifier + "_OUTPUT_DIRECTORY",
+            cmake_target_output_directory,
+        )
+
+        # Output name
+        default_product_prefix = ""
+        default_product_name = target_name
+        default_product_ext = ""
+        if target_type == "static_library":
+            static_library_prefix = generator_default_variables["STATIC_LIB_PREFIX"]
+            default_product_name = RemovePrefix(
+                default_product_name, static_library_prefix
+            )
+            default_product_prefix = static_library_prefix
+            default_product_ext = generator_default_variables["STATIC_LIB_SUFFIX"]
+
+        elif target_type in ("loadable_module", "shared_library"):
+            shared_library_prefix = generator_default_variables["SHARED_LIB_PREFIX"]
+            default_product_name = RemovePrefix(
+                default_product_name, shared_library_prefix
+            )
+            default_product_prefix = shared_library_prefix
+            default_product_ext = generator_default_variables["SHARED_LIB_SUFFIX"]
+
+        elif target_type != "executable":
+            print(
+                "ERROR: What output file should be generated?",
+                "type",
+                target_type,
+                "target",
+                target_name,
+            )
+
+        product_prefix = spec.get("product_prefix", default_product_prefix)
+        product_name = spec.get("product_name", default_product_name)
+        product_ext = spec.get("product_extension")
+        if product_ext:
+            product_ext = "." + product_ext
+        else:
+            product_ext = default_product_ext
+
+        SetTargetProperty(output, cmake_target_name, "PREFIX", product_prefix)
+        SetTargetProperty(
+            output,
+            cmake_target_name,
+            cmake_target_type.property_modifier + "_OUTPUT_NAME",
+            product_name,
+        )
+        SetTargetProperty(output, cmake_target_name, "SUFFIX", product_ext)
+
+        # Make the output of this target referenceable as a source.
+        cmake_target_output_basename = product_prefix + product_name + product_ext
+        cmake_target_output = os.path.join(
+            cmake_target_output_directory, cmake_target_output_basename
+        )
+        SetFileProperty(output, cmake_target_output, "GENERATED", ["TRUE"], "")
+
+        # Includes
+        includes = config.get("include_dirs")
+        if includes:
+            # This (target include directories) is what requires CMake 2.8.8
+            includes_name = cmake_target_name + "__include_dirs"
+            SetVariableList(
+                output,
+                includes_name,
+                [
+                    NormjoinPathForceCMakeSource(path_from_cmakelists_to_gyp, include)
+                    for include in includes
+                ],
+            )
+            output.write("set_property(TARGET ")
+            output.write(cmake_target_name)
+            output.write(" APPEND PROPERTY INCLUDE_DIRECTORIES ")
+            WriteVariable(output, includes_name, "")
+            output.write(")\n")
+
+        # Defines
+        defines = config.get("defines")
+        if defines is not None:
+            SetTargetProperty(
+                output, cmake_target_name, "COMPILE_DEFINITIONS", defines, ";"
+            )
+
+        # Compile Flags - http://www.cmake.org/Bug/view.php?id=6493
+        # CMake currently does not have target C and CXX flags.
+        # So, instead of doing...
+
+        # cflags_c = config.get('cflags_c')
+        # if cflags_c is not None:
+        #   SetTargetProperty(output, cmake_target_name,
+        #                       'C_COMPILE_FLAGS', cflags_c, ' ')
+
+        # cflags_cc = config.get('cflags_cc')
+        # if cflags_cc is not None:
+        #   SetTargetProperty(output, cmake_target_name,
+        #                       'CXX_COMPILE_FLAGS', cflags_cc, ' ')
+
+        # Instead we must...
+        cflags = config.get("cflags", [])
+        cflags_c = config.get("cflags_c", [])
+        cflags_cxx = config.get("cflags_cc", [])
+        if xcode_settings:
+            cflags = xcode_settings.GetCflags(config_to_use)
+            cflags_c = xcode_settings.GetCflagsC(config_to_use)
+            cflags_cxx = xcode_settings.GetCflagsCC(config_to_use)
+            # cflags_objc = xcode_settings.GetCflagsObjC(config_to_use)
+            # cflags_objcc = xcode_settings.GetCflagsObjCC(config_to_use)
+
+        if (not cflags_c or not c_sources) and (not cflags_cxx or not cxx_sources):
+            SetTargetProperty(output, cmake_target_name, "COMPILE_FLAGS", cflags, " ")
+
+        elif c_sources and not (s_sources or cxx_sources):
+            flags = []
+            flags.extend(cflags)
+            flags.extend(cflags_c)
+            SetTargetProperty(output, cmake_target_name, "COMPILE_FLAGS", flags, " ")
+
+        elif cxx_sources and not (s_sources or c_sources):
+            flags = []
+            flags.extend(cflags)
+            flags.extend(cflags_cxx)
+            SetTargetProperty(output, cmake_target_name, "COMPILE_FLAGS", flags, " ")
+
+        else:
+            # TODO: This is broken, one cannot generally set properties on files,
+            # as other targets may require different properties on the same files.
+            if s_sources and cflags:
+                SetFilesProperty(output, s_sources_name, "COMPILE_FLAGS", cflags, " ")
+
+            if c_sources and (cflags or cflags_c):
+                flags = []
+                flags.extend(cflags)
+                flags.extend(cflags_c)
+                SetFilesProperty(output, c_sources_name, "COMPILE_FLAGS", flags, " ")
+
+            if cxx_sources and (cflags or cflags_cxx):
+                flags = []
+                flags.extend(cflags)
+                flags.extend(cflags_cxx)
+                SetFilesProperty(output, cxx_sources_name, "COMPILE_FLAGS", flags, " ")
+
+        # Linker flags
+        ldflags = config.get("ldflags")
+        if ldflags is not None:
+            SetTargetProperty(output, cmake_target_name, "LINK_FLAGS", ldflags, " ")
+
+        # XCode settings
+        xcode_settings = config.get("xcode_settings", {})
+        for xcode_setting, xcode_value in xcode_settings.items():
+            SetTargetProperty(
+                output,
+                cmake_target_name,
+                "XCODE_ATTRIBUTE_%s" % xcode_setting,
+                xcode_value,
+                "" if isinstance(xcode_value, str) else " ",
+            )
+
+    # Note on Dependencies and Libraries:
+    # CMake wants to handle link order, resolving the link line up front.
+    # Gyp does not retain or enforce specifying enough information to do so.
+    # So do as other gyp generators and use --start-group and --end-group.
+    # Give CMake as little information as possible so that it doesn't mess it up.
+
+    # Dependencies
+    rawDeps = spec.get("dependencies", [])
+
+    static_deps = []
+    shared_deps = []
+    other_deps = []
+    for rawDep in rawDeps:
+        dep_cmake_name = namer.CreateCMakeTargetName(rawDep)
+        dep_spec = target_dicts.get(rawDep, {})
+        dep_target_type = dep_spec.get("type", None)
+
+        if dep_target_type == "static_library":
+            static_deps.append(dep_cmake_name)
+        elif dep_target_type == "shared_library":
+            shared_deps.append(dep_cmake_name)
+        else:
+            other_deps.append(dep_cmake_name)
+
+    # ensure all external dependencies are complete before internal dependencies
+    # extra_deps currently only depend on their own deps, so otherwise run early
+    if static_deps or shared_deps or other_deps:
+        for extra_dep in extra_deps:
+            output.write("add_dependencies(")
+            output.write(extra_dep)
+            output.write("\n")
+            for deps in (static_deps, shared_deps, other_deps):
+                for dep in gyp.common.uniquer(deps):
+                    output.write("  ")
+                    output.write(dep)
+                    output.write("\n")
+            output.write(")\n")
+
+    linkable = target_type in ("executable", "loadable_module", "shared_library")
+    other_deps.extend(extra_deps)
+    if other_deps or (not linkable and (static_deps or shared_deps)):
+        output.write("add_dependencies(")
+        output.write(cmake_target_name)
+        output.write("\n")
+        for dep in gyp.common.uniquer(other_deps):
+            output.write("  ")
+            output.write(dep)
+            output.write("\n")
+        if not linkable:
+            for deps in (static_deps, shared_deps):
+                for lib_dep in gyp.common.uniquer(deps):
+                    output.write("  ")
+                    output.write(lib_dep)
+                    output.write("\n")
+        output.write(")\n")
+
+    # Libraries
+    if linkable:
+        external_libs = [lib for lib in spec.get("libraries", []) if len(lib) > 0]
+        if external_libs or static_deps or shared_deps:
+            output.write("target_link_libraries(")
+            output.write(cmake_target_name)
+            output.write("\n")
+            if static_deps:
+                write_group = circular_libs and len(static_deps) > 1 and flavor != "mac"
+                if write_group:
+                    output.write("-Wl,--start-group\n")
+                for dep in gyp.common.uniquer(static_deps):
+                    output.write("  ")
+                    output.write(dep)
+                    output.write("\n")
+                if write_group:
+                    output.write("-Wl,--end-group\n")
+            if shared_deps:
+                for dep in gyp.common.uniquer(shared_deps):
+                    output.write("  ")
+                    output.write(dep)
+                    output.write("\n")
+            if external_libs:
+                for lib in gyp.common.uniquer(external_libs):
+                    output.write('  "')
+                    output.write(RemovePrefix(lib, "$(SDKROOT)"))
+                    output.write('"\n')
+
+            output.write(")\n")
+
+    UnsetVariable(output, "TOOLSET")
+    UnsetVariable(output, "TARGET")
+
+
+def GenerateOutputForConfig(target_list, target_dicts, data, params, config_to_use):
+    options = params["options"]
+    generator_flags = params["generator_flags"]
+    flavor = gyp.common.GetFlavor(params)
+
+    # generator_dir: relative path from pwd to where make puts build files.
+    # Makes migrating from make to cmake easier, cmake doesn't put anything here.
+    # Each Gyp configuration creates a different CMakeLists.txt file
+    # to avoid incompatibilities between Gyp and CMake configurations.
+    generator_dir = os.path.relpath(options.generator_output or ".")
+
+    # output_dir: relative path from generator_dir to the build directory.
+    output_dir = generator_flags.get("output_dir", "out")
+
+    # build_dir: relative path from source root to our output files.
+    # e.g. "out/Debug"
+    build_dir = os.path.normpath(os.path.join(generator_dir, output_dir, config_to_use))
+
+    toplevel_build = os.path.join(options.toplevel_dir, build_dir)
+
+    output_file = os.path.join(toplevel_build, "CMakeLists.txt")
+    gyp.common.EnsureDirExists(output_file)
+
+    output = open(output_file, "w")
+    output.write("cmake_minimum_required(VERSION 2.8.8 FATAL_ERROR)\n")
+    output.write("cmake_policy(VERSION 2.8.8)\n")
+
+    gyp_file, project_target, _ = gyp.common.ParseQualifiedTarget(target_list[-1])
+    output.write("project(")
+    output.write(project_target)
+    output.write(")\n")
+
+    SetVariable(output, "configuration", config_to_use)
+
+    ar = None
+    cc = None
+    cxx = None
+
+    make_global_settings = data[gyp_file].get("make_global_settings", [])
+    build_to_top = gyp.common.InvertRelativePath(build_dir, options.toplevel_dir)
+    for key, value in make_global_settings:
+        if key == "AR":
+            ar = os.path.join(build_to_top, value)
+        if key == "CC":
+            cc = os.path.join(build_to_top, value)
+        if key == "CXX":
+            cxx = os.path.join(build_to_top, value)
+
+    ar = gyp.common.GetEnvironFallback(["AR_target", "AR"], ar)
+    cc = gyp.common.GetEnvironFallback(["CC_target", "CC"], cc)
+    cxx = gyp.common.GetEnvironFallback(["CXX_target", "CXX"], cxx)
+
+    if ar:
+        SetVariable(output, "CMAKE_AR", ar)
+    if cc:
+        SetVariable(output, "CMAKE_C_COMPILER", cc)
+    if cxx:
+        SetVariable(output, "CMAKE_CXX_COMPILER", cxx)
+
+    # The following appears to be as-yet undocumented.
+    # http://public.kitware.com/Bug/view.php?id=8392
+    output.write("enable_language(ASM)\n")
+    # ASM-ATT does not support .S files.
+    # output.write('enable_language(ASM-ATT)\n')
+
+    if cc:
+        SetVariable(output, "CMAKE_ASM_COMPILER", cc)
+
+    SetVariable(output, "builddir", "${CMAKE_CURRENT_BINARY_DIR}")
+    SetVariable(output, "obj", "${builddir}/obj")
+    output.write("\n")
+
+    # TODO: Undocumented/unsupported (the CMake Java generator depends on it).
+    # CMake by default names the object resulting from foo.c to be foo.c.o.
+    # Gyp traditionally names the object resulting from foo.c foo.o.
+    # This should be irrelevant, but some targets extract .o files from .a
+    # and depend on the name of the extracted .o files.
+    output.write("set(CMAKE_C_OUTPUT_EXTENSION_REPLACE 1)\n")
+    output.write("set(CMAKE_CXX_OUTPUT_EXTENSION_REPLACE 1)\n")
+    output.write("\n")
+
+    # Force ninja to use rsp files. Otherwise link and ar lines can get too long,
+    # resulting in 'Argument list too long' errors.
+    # However, rsp files don't work correctly on Mac.
+    if flavor != "mac":
+        output.write("set(CMAKE_NINJA_FORCE_RESPONSE_FILE 1)\n")
+    output.write("\n")
+
+    namer = CMakeNamer(target_list)
+
+    # The list of targets upon which the 'all' target should depend.
+    # CMake has it's own implicit 'all' target, one is not created explicitly.
+    all_qualified_targets = set()
+    for build_file in params["build_files"]:
+        for qualified_target in gyp.common.AllTargets(
+            target_list, target_dicts, os.path.normpath(build_file)
+        ):
+            all_qualified_targets.add(qualified_target)
+
+    for qualified_target in target_list:
+        if flavor == "mac":
+            gyp_file, _, _ = gyp.common.ParseQualifiedTarget(qualified_target)
+            spec = target_dicts[qualified_target]
+            gyp.xcode_emulation.MergeGlobalXcodeSettingsToSpec(data[gyp_file], spec)
+
+        WriteTarget(
+            namer,
+            qualified_target,
+            target_dicts,
+            build_dir,
+            config_to_use,
+            options,
+            generator_flags,
+            all_qualified_targets,
+            flavor,
+            output,
+        )
+
+    output.close()
+
+
+def PerformBuild(data, configurations, params):
+    options = params["options"]
+    generator_flags = params["generator_flags"]
+
+    # generator_dir: relative path from pwd to where make puts build files.
+    # Makes migrating from make to cmake easier, cmake doesn't put anything here.
+    generator_dir = os.path.relpath(options.generator_output or ".")
+
+    # output_dir: relative path from generator_dir to the build directory.
+    output_dir = generator_flags.get("output_dir", "out")
+
+    for config_name in configurations:
+        # build_dir: relative path from source root to our output files.
+        # e.g. "out/Debug"
+        build_dir = os.path.normpath(
+            os.path.join(generator_dir, output_dir, config_name)
+        )
+        arguments = ["cmake", "-G", "Ninja"]
+        print(f"Generating [{config_name}]: {arguments}")
+        subprocess.check_call(arguments, cwd=build_dir)
+
+        arguments = ["ninja", "-C", build_dir]
+        print(f"Building [{config_name}]: {arguments}")
+        subprocess.check_call(arguments)
+
+
+def CallGenerateOutputForConfig(arglist):
+    # Ignore the interrupt signal so that the parent process catches it and
+    # kills all multiprocessing children.
+    signal.signal(signal.SIGINT, signal.SIG_IGN)
+
+    target_list, target_dicts, data, params, config_name = arglist
+    GenerateOutputForConfig(target_list, target_dicts, data, params, config_name)
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    user_config = params.get("generator_flags", {}).get("config", None)
+    if user_config:
+        GenerateOutputForConfig(target_list, target_dicts, data, params, user_config)
+    else:
+        config_names = target_dicts[target_list[0]]["configurations"]
+        if params["parallel"]:
+            try:
+                pool = multiprocessing.Pool(len(config_names))
+                arglists = []
+                for config_name in config_names:
+                    arglists.append(
+                        (target_list, target_dicts, data, params, config_name)
+                    )
+                    pool.map(CallGenerateOutputForConfig, arglists)
+            except KeyboardInterrupt as e:
+                pool.terminate()
+                raise e
+        else:
+            for config_name in config_names:
+                GenerateOutputForConfig(
+                    target_list, target_dicts, data, params, config_name
+                )
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/compile_commands_json.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/compile_commands_json.py
new file mode 100644
index 0000000..f330a04
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/compile_commands_json.py
@@ -0,0 +1,120 @@
+# Copyright (c) 2016 Ben Noordhuis <info@bnoordhuis.nl>. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import gyp.common
+import gyp.xcode_emulation
+import json
+import os
+
+generator_additional_non_configuration_keys = []
+generator_additional_path_sections = []
+generator_extra_sources_for_rules = []
+generator_filelist_paths = None
+generator_supports_multiple_toolsets = True
+generator_wants_sorted_dependencies = False
+
+# Lifted from make.py.  The actual values don't matter much.
+generator_default_variables = {
+    "CONFIGURATION_NAME": "$(BUILDTYPE)",
+    "EXECUTABLE_PREFIX": "",
+    "EXECUTABLE_SUFFIX": "",
+    "INTERMEDIATE_DIR": "$(obj).$(TOOLSET)/$(TARGET)/geni",
+    "PRODUCT_DIR": "$(builddir)",
+    "RULE_INPUT_DIRNAME": "%(INPUT_DIRNAME)s",
+    "RULE_INPUT_EXT": "$(suffix $<)",
+    "RULE_INPUT_NAME": "$(notdir $<)",
+    "RULE_INPUT_PATH": "$(abspath $<)",
+    "RULE_INPUT_ROOT": "%(INPUT_ROOT)s",
+    "SHARED_INTERMEDIATE_DIR": "$(obj)/gen",
+    "SHARED_LIB_PREFIX": "lib",
+    "STATIC_LIB_PREFIX": "lib",
+    "STATIC_LIB_SUFFIX": ".a",
+}
+
+
+def IsMac(params):
+    return "mac" == gyp.common.GetFlavor(params)
+
+
+def CalculateVariables(default_variables, params):
+    default_variables.setdefault("OS", gyp.common.GetFlavor(params))
+
+
+def AddCommandsForTarget(cwd, target, params, per_config_commands):
+    output_dir = params["generator_flags"].get("output_dir", "out")
+    for configuration_name, configuration in target["configurations"].items():
+        if IsMac(params):
+            xcode_settings = gyp.xcode_emulation.XcodeSettings(target)
+            cflags = xcode_settings.GetCflags(configuration_name)
+            cflags_c = xcode_settings.GetCflagsC(configuration_name)
+            cflags_cc = xcode_settings.GetCflagsCC(configuration_name)
+        else:
+            cflags = configuration.get("cflags", [])
+            cflags_c = configuration.get("cflags_c", [])
+            cflags_cc = configuration.get("cflags_cc", [])
+
+        cflags_c = cflags + cflags_c
+        cflags_cc = cflags + cflags_cc
+
+        defines = configuration.get("defines", [])
+        defines = ["-D" + s for s in defines]
+
+        # TODO(bnoordhuis) Handle generated source files.
+        extensions = (".c", ".cc", ".cpp", ".cxx")
+        sources = [s for s in target.get("sources", []) if s.endswith(extensions)]
+
+        def resolve(filename):
+            return os.path.abspath(os.path.join(cwd, filename))
+
+        # TODO(bnoordhuis) Handle generated header files.
+        include_dirs = configuration.get("include_dirs", [])
+        include_dirs = [s for s in include_dirs if not s.startswith("$(obj)")]
+        includes = ["-I" + resolve(s) for s in include_dirs]
+
+        defines = gyp.common.EncodePOSIXShellList(defines)
+        includes = gyp.common.EncodePOSIXShellList(includes)
+        cflags_c = gyp.common.EncodePOSIXShellList(cflags_c)
+        cflags_cc = gyp.common.EncodePOSIXShellList(cflags_cc)
+
+        commands = per_config_commands.setdefault(configuration_name, [])
+        for source in sources:
+            file = resolve(source)
+            isc = source.endswith(".c")
+            cc = "cc" if isc else "c++"
+            cflags = cflags_c if isc else cflags_cc
+            command = " ".join(
+                (
+                    cc,
+                    defines,
+                    includes,
+                    cflags,
+                    "-c",
+                    gyp.common.EncodePOSIXShellArgument(file),
+                )
+            )
+            commands.append(dict(command=command, directory=output_dir, file=file))
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    per_config_commands = {}
+    for qualified_target, target in target_dicts.items():
+        build_file, target_name, toolset = gyp.common.ParseQualifiedTarget(
+            qualified_target
+        )
+        if IsMac(params):
+            settings = data[build_file]
+            gyp.xcode_emulation.MergeGlobalXcodeSettingsToSpec(settings, target)
+        cwd = os.path.dirname(build_file)
+        AddCommandsForTarget(cwd, target, params, per_config_commands)
+
+    output_dir = params["generator_flags"].get("output_dir", "out")
+    for configuration_name, commands in per_config_commands.items():
+        filename = os.path.join(output_dir, configuration_name, "compile_commands.json")
+        gyp.common.EnsureDirExists(filename)
+        fp = open(filename, "w")
+        json.dump(commands, fp=fp, indent=0, check_circular=False)
+
+
+def PerformBuild(data, configurations, params):
+    pass
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/dump_dependency_json.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/dump_dependency_json.py
new file mode 100644
index 0000000..99d5c1f
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/dump_dependency_json.py
@@ -0,0 +1,103 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+import os
+import gyp
+import gyp.common
+import gyp.msvs_emulation
+import json
+
+generator_supports_multiple_toolsets = True
+
+generator_wants_static_library_dependencies_adjusted = False
+
+generator_filelist_paths = {}
+
+generator_default_variables = {}
+for dirname in [
+    "INTERMEDIATE_DIR",
+    "SHARED_INTERMEDIATE_DIR",
+    "PRODUCT_DIR",
+    "LIB_DIR",
+    "SHARED_LIB_DIR",
+]:
+    # Some gyp steps fail if these are empty(!).
+    generator_default_variables[dirname] = "dir"
+for unused in [
+    "RULE_INPUT_PATH",
+    "RULE_INPUT_ROOT",
+    "RULE_INPUT_NAME",
+    "RULE_INPUT_DIRNAME",
+    "RULE_INPUT_EXT",
+    "EXECUTABLE_PREFIX",
+    "EXECUTABLE_SUFFIX",
+    "STATIC_LIB_PREFIX",
+    "STATIC_LIB_SUFFIX",
+    "SHARED_LIB_PREFIX",
+    "SHARED_LIB_SUFFIX",
+    "CONFIGURATION_NAME",
+]:
+    generator_default_variables[unused] = ""
+
+
+def CalculateVariables(default_variables, params):
+    generator_flags = params.get("generator_flags", {})
+    for key, val in generator_flags.items():
+        default_variables.setdefault(key, val)
+    default_variables.setdefault("OS", gyp.common.GetFlavor(params))
+
+    flavor = gyp.common.GetFlavor(params)
+    if flavor == "win":
+        gyp.msvs_emulation.CalculateCommonVariables(default_variables, params)
+
+
+def CalculateGeneratorInputInfo(params):
+    """Calculate the generator specific info that gets fed to input (called by
+  gyp)."""
+    generator_flags = params.get("generator_flags", {})
+    if generator_flags.get("adjust_static_libraries", False):
+        global generator_wants_static_library_dependencies_adjusted
+        generator_wants_static_library_dependencies_adjusted = True
+
+    toplevel = params["options"].toplevel_dir
+    generator_dir = os.path.relpath(params["options"].generator_output or ".")
+    # output_dir: relative path from generator_dir to the build directory.
+    output_dir = generator_flags.get("output_dir", "out")
+    qualified_out_dir = os.path.normpath(
+        os.path.join(toplevel, generator_dir, output_dir, "gypfiles")
+    )
+    global generator_filelist_paths
+    generator_filelist_paths = {
+        "toplevel": toplevel,
+        "qualified_out_dir": qualified_out_dir,
+    }
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    # Map of target -> list of targets it depends on.
+    edges = {}
+
+    # Queue of targets to visit.
+    targets_to_visit = target_list[:]
+
+    while len(targets_to_visit) > 0:
+        target = targets_to_visit.pop()
+        if target in edges:
+            continue
+        edges[target] = []
+
+        for dep in target_dicts[target].get("dependencies", []):
+            edges[target].append(dep)
+            targets_to_visit.append(dep)
+
+    try:
+        filepath = params["generator_flags"]["output_dir"]
+    except KeyError:
+        filepath = "."
+    filename = os.path.join(filepath, "dump.json")
+    f = open(filename, "w")
+    json.dump(edges, f)
+    f.close()
+    print("Wrote json to %s." % filename)
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/eclipse.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/eclipse.py
new file mode 100644
index 0000000..1ff0dc8
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/eclipse.py
@@ -0,0 +1,464 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""GYP backend that generates Eclipse CDT settings files.
+
+This backend DOES NOT generate Eclipse CDT projects. Instead, it generates XML
+files that can be imported into an Eclipse CDT project. The XML file contains a
+list of include paths and symbols (i.e. defines).
+
+Because a full .cproject definition is not created by this generator, it's not
+possible to properly define the include dirs and symbols for each file
+individually.  Instead, one set of includes/symbols is generated for the entire
+project.  This works fairly well (and is a vast improvement in general), but may
+still result in a few indexer issues here and there.
+
+This generator has no automated tests, so expect it to be broken.
+"""
+
+from xml.sax.saxutils import escape
+import os.path
+import subprocess
+import gyp
+import gyp.common
+import gyp.msvs_emulation
+import shlex
+import xml.etree.cElementTree as ET
+
+generator_wants_static_library_dependencies_adjusted = False
+
+generator_default_variables = {}
+
+for dirname in ["INTERMEDIATE_DIR", "PRODUCT_DIR", "LIB_DIR", "SHARED_LIB_DIR"]:
+    # Some gyp steps fail if these are empty(!), so we convert them to variables
+    generator_default_variables[dirname] = "$" + dirname
+
+for unused in [
+    "RULE_INPUT_PATH",
+    "RULE_INPUT_ROOT",
+    "RULE_INPUT_NAME",
+    "RULE_INPUT_DIRNAME",
+    "RULE_INPUT_EXT",
+    "EXECUTABLE_PREFIX",
+    "EXECUTABLE_SUFFIX",
+    "STATIC_LIB_PREFIX",
+    "STATIC_LIB_SUFFIX",
+    "SHARED_LIB_PREFIX",
+    "SHARED_LIB_SUFFIX",
+    "CONFIGURATION_NAME",
+]:
+    generator_default_variables[unused] = ""
+
+# Include dirs will occasionally use the SHARED_INTERMEDIATE_DIR variable as
+# part of the path when dealing with generated headers.  This value will be
+# replaced dynamically for each configuration.
+generator_default_variables["SHARED_INTERMEDIATE_DIR"] = "$SHARED_INTERMEDIATE_DIR"
+
+
+def CalculateVariables(default_variables, params):
+    generator_flags = params.get("generator_flags", {})
+    for key, val in generator_flags.items():
+        default_variables.setdefault(key, val)
+    flavor = gyp.common.GetFlavor(params)
+    default_variables.setdefault("OS", flavor)
+    if flavor == "win":
+        gyp.msvs_emulation.CalculateCommonVariables(default_variables, params)
+
+
+def CalculateGeneratorInputInfo(params):
+    """Calculate the generator specific info that gets fed to input (called by
+  gyp)."""
+    generator_flags = params.get("generator_flags", {})
+    if generator_flags.get("adjust_static_libraries", False):
+        global generator_wants_static_library_dependencies_adjusted
+        generator_wants_static_library_dependencies_adjusted = True
+
+
+def GetAllIncludeDirectories(
+    target_list,
+    target_dicts,
+    shared_intermediate_dirs,
+    config_name,
+    params,
+    compiler_path,
+):
+    """Calculate the set of include directories to be used.
+
+  Returns:
+    A list including all the include_dir's specified for every target followed
+    by any include directories that were added as cflag compiler options.
+  """
+
+    gyp_includes_set = set()
+    compiler_includes_list = []
+
+    # Find compiler's default include dirs.
+    if compiler_path:
+        command = shlex.split(compiler_path)
+        command.extend(["-E", "-xc++", "-v", "-"])
+        proc = subprocess.Popen(
+            args=command,
+            stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
+        output = proc.communicate()[1].decode("utf-8")
+        # Extract the list of include dirs from the output, which has this format:
+        #   ...
+        #   #include "..." search starts here:
+        #   #include <...> search starts here:
+        #    /usr/include/c++/4.6
+        #    /usr/local/include
+        #   End of search list.
+        #   ...
+        in_include_list = False
+        for line in output.splitlines():
+            if line.startswith("#include"):
+                in_include_list = True
+                continue
+            if line.startswith("End of search list."):
+                break
+            if in_include_list:
+                include_dir = line.strip()
+                if include_dir not in compiler_includes_list:
+                    compiler_includes_list.append(include_dir)
+
+    flavor = gyp.common.GetFlavor(params)
+    if flavor == "win":
+        generator_flags = params.get("generator_flags", {})
+    for target_name in target_list:
+        target = target_dicts[target_name]
+        if config_name in target["configurations"]:
+            config = target["configurations"][config_name]
+
+            # Look for any include dirs that were explicitly added via cflags. This
+            # may be done in gyp files to force certain includes to come at the end.
+            # TODO(jgreenwald): Change the gyp files to not abuse cflags for this, and
+            # remove this.
+            if flavor == "win":
+                msvs_settings = gyp.msvs_emulation.MsvsSettings(target, generator_flags)
+                cflags = msvs_settings.GetCflags(config_name)
+            else:
+                cflags = config["cflags"]
+            for cflag in cflags:
+                if cflag.startswith("-I"):
+                    include_dir = cflag[2:]
+                    if include_dir not in compiler_includes_list:
+                        compiler_includes_list.append(include_dir)
+
+            # Find standard gyp include dirs.
+            if "include_dirs" in config:
+                include_dirs = config["include_dirs"]
+                for shared_intermediate_dir in shared_intermediate_dirs:
+                    for include_dir in include_dirs:
+                        include_dir = include_dir.replace(
+                            "$SHARED_INTERMEDIATE_DIR", shared_intermediate_dir
+                        )
+                        if not os.path.isabs(include_dir):
+                            base_dir = os.path.dirname(target_name)
+
+                            include_dir = base_dir + "/" + include_dir
+                            include_dir = os.path.abspath(include_dir)
+
+                        gyp_includes_set.add(include_dir)
+
+    # Generate a list that has all the include dirs.
+    all_includes_list = list(gyp_includes_set)
+    all_includes_list.sort()
+    for compiler_include in compiler_includes_list:
+        if compiler_include not in gyp_includes_set:
+            all_includes_list.append(compiler_include)
+
+    # All done.
+    return all_includes_list
+
+
+def GetCompilerPath(target_list, data, options):
+    """Determine a command that can be used to invoke the compiler.
+
+  Returns:
+    If this is a gyp project that has explicit make settings, try to determine
+    the compiler from that.  Otherwise, see if a compiler was specified via the
+    CC_target environment variable.
+  """
+    # First, see if the compiler is configured in make's settings.
+    build_file, _, _ = gyp.common.ParseQualifiedTarget(target_list[0])
+    make_global_settings_dict = data[build_file].get("make_global_settings", {})
+    for key, value in make_global_settings_dict:
+        if key in ["CC", "CXX"]:
+            return os.path.join(options.toplevel_dir, value)
+
+    # Check to see if the compiler was specified as an environment variable.
+    for key in ["CC_target", "CC", "CXX"]:
+        compiler = os.environ.get(key)
+        if compiler:
+            return compiler
+
+    return "gcc"
+
+
+def GetAllDefines(target_list, target_dicts, data, config_name, params, compiler_path):
+    """Calculate the defines for a project.
+
+  Returns:
+    A dict that includes explicit defines declared in gyp files along with all
+    of the default defines that the compiler uses.
+  """
+
+    # Get defines declared in the gyp files.
+    all_defines = {}
+    flavor = gyp.common.GetFlavor(params)
+    if flavor == "win":
+        generator_flags = params.get("generator_flags", {})
+    for target_name in target_list:
+        target = target_dicts[target_name]
+
+        if flavor == "win":
+            msvs_settings = gyp.msvs_emulation.MsvsSettings(target, generator_flags)
+            extra_defines = msvs_settings.GetComputedDefines(config_name)
+        else:
+            extra_defines = []
+        if config_name in target["configurations"]:
+            config = target["configurations"][config_name]
+            target_defines = config["defines"]
+        else:
+            target_defines = []
+        for define in target_defines + extra_defines:
+            split_define = define.split("=", 1)
+            if len(split_define) == 1:
+                split_define.append("1")
+            if split_define[0].strip() in all_defines:
+                # Already defined
+                continue
+            all_defines[split_define[0].strip()] = split_define[1].strip()
+    # Get default compiler defines (if possible).
+    if flavor == "win":
+        return all_defines  # Default defines already processed in the loop above.
+    if compiler_path:
+        command = shlex.split(compiler_path)
+        command.extend(["-E", "-dM", "-"])
+        cpp_proc = subprocess.Popen(
+            args=command, cwd=".", stdin=subprocess.PIPE, stdout=subprocess.PIPE
+        )
+        cpp_output = cpp_proc.communicate()[0].decode("utf-8")
+        cpp_lines = cpp_output.split("\n")
+        for cpp_line in cpp_lines:
+            if not cpp_line.strip():
+                continue
+            cpp_line_parts = cpp_line.split(" ", 2)
+            key = cpp_line_parts[1]
+            if len(cpp_line_parts) >= 3:
+                val = cpp_line_parts[2]
+            else:
+                val = "1"
+            all_defines[key] = val
+
+    return all_defines
+
+
+def WriteIncludePaths(out, eclipse_langs, include_dirs):
+    """Write the includes section of a CDT settings export file."""
+
+    out.write(
+        '  <section name="org.eclipse.cdt.internal.ui.wizards.'
+        'settingswizards.IncludePaths">\n'
+    )
+    out.write('    <language name="holder for library settings"></language>\n')
+    for lang in eclipse_langs:
+        out.write('    <language name="%s">\n' % lang)
+        for include_dir in include_dirs:
+            out.write(
+                '      <includepath workspace_path="false">%s</includepath>\n'
+                % include_dir
+            )
+        out.write("    </language>\n")
+    out.write("  </section>\n")
+
+
+def WriteMacros(out, eclipse_langs, defines):
+    """Write the macros section of a CDT settings export file."""
+
+    out.write(
+        '  <section name="org.eclipse.cdt.internal.ui.wizards.'
+        'settingswizards.Macros">\n'
+    )
+    out.write('    <language name="holder for library settings"></language>\n')
+    for lang in eclipse_langs:
+        out.write('    <language name="%s">\n' % lang)
+        for key in sorted(defines):
+            out.write(
+                "      <macro><name>%s</name><value>%s</value></macro>\n"
+                % (escape(key), escape(defines[key]))
+            )
+        out.write("    </language>\n")
+    out.write("  </section>\n")
+
+
+def GenerateOutputForConfig(target_list, target_dicts, data, params, config_name):
+    options = params["options"]
+    generator_flags = params.get("generator_flags", {})
+
+    # build_dir: relative path from source root to our output files.
+    # e.g. "out/Debug"
+    build_dir = os.path.join(generator_flags.get("output_dir", "out"), config_name)
+
+    toplevel_build = os.path.join(options.toplevel_dir, build_dir)
+    # Ninja uses out/Debug/gen while make uses out/Debug/obj/gen as the
+    # SHARED_INTERMEDIATE_DIR. Include both possible locations.
+    shared_intermediate_dirs = [
+        os.path.join(toplevel_build, "obj", "gen"),
+        os.path.join(toplevel_build, "gen"),
+    ]
+
+    GenerateCdtSettingsFile(
+        target_list,
+        target_dicts,
+        data,
+        params,
+        config_name,
+        os.path.join(toplevel_build, "eclipse-cdt-settings.xml"),
+        options,
+        shared_intermediate_dirs,
+    )
+    GenerateClasspathFile(
+        target_list,
+        target_dicts,
+        options.toplevel_dir,
+        toplevel_build,
+        os.path.join(toplevel_build, "eclipse-classpath.xml"),
+    )
+
+
+def GenerateCdtSettingsFile(
+    target_list,
+    target_dicts,
+    data,
+    params,
+    config_name,
+    out_name,
+    options,
+    shared_intermediate_dirs,
+):
+    gyp.common.EnsureDirExists(out_name)
+    with open(out_name, "w") as out:
+        out.write('<?xml version="1.0" encoding="UTF-8"?>\n')
+        out.write("<cdtprojectproperties>\n")
+
+        eclipse_langs = [
+            "C++ Source File",
+            "C Source File",
+            "Assembly Source File",
+            "GNU C++",
+            "GNU C",
+            "Assembly",
+        ]
+        compiler_path = GetCompilerPath(target_list, data, options)
+        include_dirs = GetAllIncludeDirectories(
+            target_list,
+            target_dicts,
+            shared_intermediate_dirs,
+            config_name,
+            params,
+            compiler_path,
+        )
+        WriteIncludePaths(out, eclipse_langs, include_dirs)
+        defines = GetAllDefines(
+            target_list, target_dicts, data, config_name, params, compiler_path
+        )
+        WriteMacros(out, eclipse_langs, defines)
+
+        out.write("</cdtprojectproperties>\n")
+
+
+def GenerateClasspathFile(
+    target_list, target_dicts, toplevel_dir, toplevel_build, out_name
+):
+    """Generates a classpath file suitable for symbol navigation and code
+  completion of Java code (such as in Android projects) by finding all
+  .java and .jar files used as action inputs."""
+    gyp.common.EnsureDirExists(out_name)
+    result = ET.Element("classpath")
+
+    def AddElements(kind, paths):
+        # First, we need to normalize the paths so they are all relative to the
+        # toplevel dir.
+        rel_paths = set()
+        for path in paths:
+            if os.path.isabs(path):
+                rel_paths.add(os.path.relpath(path, toplevel_dir))
+            else:
+                rel_paths.add(path)
+
+        for path in sorted(rel_paths):
+            entry_element = ET.SubElement(result, "classpathentry")
+            entry_element.set("kind", kind)
+            entry_element.set("path", path)
+
+    AddElements("lib", GetJavaJars(target_list, target_dicts, toplevel_dir))
+    AddElements("src", GetJavaSourceDirs(target_list, target_dicts, toplevel_dir))
+    # Include the standard JRE container and a dummy out folder
+    AddElements("con", ["org.eclipse.jdt.launching.JRE_CONTAINER"])
+    # Include a dummy out folder so that Eclipse doesn't use the default /bin
+    # folder in the root of the project.
+    AddElements("output", [os.path.join(toplevel_build, ".eclipse-java-build")])
+
+    ET.ElementTree(result).write(out_name)
+
+
+def GetJavaJars(target_list, target_dicts, toplevel_dir):
+    """Generates a sequence of all .jars used as inputs."""
+    for target_name in target_list:
+        target = target_dicts[target_name]
+        for action in target.get("actions", []):
+            for input_ in action["inputs"]:
+                if os.path.splitext(input_)[1] == ".jar" and not input_.startswith("$"):
+                    if os.path.isabs(input_):
+                        yield input_
+                    else:
+                        yield os.path.join(os.path.dirname(target_name), input_)
+
+
+def GetJavaSourceDirs(target_list, target_dicts, toplevel_dir):
+    """Generates a sequence of all likely java package root directories."""
+    for target_name in target_list:
+        target = target_dicts[target_name]
+        for action in target.get("actions", []):
+            for input_ in action["inputs"]:
+                if os.path.splitext(input_)[1] == ".java" and not input_.startswith(
+                    "$"
+                ):
+                    dir_ = os.path.dirname(
+                        os.path.join(os.path.dirname(target_name), input_)
+                    )
+                    # If there is a parent 'src' or 'java' folder, navigate up to it -
+                    # these are canonical package root names in Chromium.  This will
+                    # break if 'src' or 'java' exists in the package structure. This
+                    # could be further improved by inspecting the java file for the
+                    # package name if this proves to be too fragile in practice.
+                    parent_search = dir_
+                    while os.path.basename(parent_search) not in ["src", "java"]:
+                        parent_search, _ = os.path.split(parent_search)
+                        if not parent_search or parent_search == toplevel_dir:
+                            # Didn't find a known root, just return the original path
+                            yield dir_
+                            break
+                    else:
+                        yield parent_search
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    """Generate an XML settings file that can be imported into a CDT project."""
+
+    if params["options"].generator_output:
+        raise NotImplementedError("--generator_output not implemented for eclipse")
+
+    user_config = params.get("generator_flags", {}).get("config", None)
+    if user_config:
+        GenerateOutputForConfig(target_list, target_dicts, data, params, user_config)
+    else:
+        config_names = target_dicts[target_list[0]]["configurations"]
+        for config_name in config_names:
+            GenerateOutputForConfig(
+                target_list, target_dicts, data, params, config_name
+            )
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/gypd.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/gypd.py
new file mode 100644
index 0000000..4171704
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/gypd.py
@@ -0,0 +1,89 @@
+# Copyright (c) 2011 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""gypd output module
+
+This module produces gyp input as its output.  Output files are given the
+.gypd extension to avoid overwriting the .gyp files that they are generated
+from.  Internal references to .gyp files (such as those found in
+"dependencies" sections) are not adjusted to point to .gypd files instead;
+unlike other paths, which are relative to the .gyp or .gypd file, such paths
+are relative to the directory from which gyp was run to create the .gypd file.
+
+This generator module is intended to be a sample and a debugging aid, hence
+the "d" for "debug" in .gypd.  It is useful to inspect the results of the
+various merges, expansions, and conditional evaluations performed by gyp
+and to see a representation of what would be fed to a generator module.
+
+It's not advisable to rename .gypd files produced by this module to .gyp,
+because they will have all merges, expansions, and evaluations already
+performed and the relevant constructs not present in the output; paths to
+dependencies may be wrong; and various sections that do not belong in .gyp
+files such as such as "included_files" and "*_excluded" will be present.
+Output will also be stripped of comments.  This is not intended to be a
+general-purpose gyp pretty-printer; for that, you probably just want to
+run "pprint.pprint(eval(open('source.gyp').read()))", which will still strip
+comments but won't do all of the other things done to this module's output.
+
+The specific formatting of the output generated by this module is subject
+to change.
+"""
+
+
+import gyp.common
+import pprint
+
+
+# These variables should just be spit back out as variable references.
+_generator_identity_variables = [
+    "CONFIGURATION_NAME",
+    "EXECUTABLE_PREFIX",
+    "EXECUTABLE_SUFFIX",
+    "INTERMEDIATE_DIR",
+    "LIB_DIR",
+    "PRODUCT_DIR",
+    "RULE_INPUT_ROOT",
+    "RULE_INPUT_DIRNAME",
+    "RULE_INPUT_EXT",
+    "RULE_INPUT_NAME",
+    "RULE_INPUT_PATH",
+    "SHARED_INTERMEDIATE_DIR",
+    "SHARED_LIB_DIR",
+    "SHARED_LIB_PREFIX",
+    "SHARED_LIB_SUFFIX",
+    "STATIC_LIB_PREFIX",
+    "STATIC_LIB_SUFFIX",
+]
+
+# gypd doesn't define a default value for OS like many other generator
+# modules.  Specify "-D OS=whatever" on the command line to provide a value.
+generator_default_variables = {}
+
+# gypd supports multiple toolsets
+generator_supports_multiple_toolsets = True
+
+# TODO(mark): This always uses <, which isn't right.  The input module should
+# notify the generator to tell it which phase it is operating in, and this
+# module should use < for the early phase and then switch to > for the late
+# phase.  Bonus points for carrying @ back into the output too.
+for v in _generator_identity_variables:
+    generator_default_variables[v] = "<(%s)" % v
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    output_files = {}
+    for qualified_target in target_list:
+        [input_file, target] = gyp.common.ParseQualifiedTarget(qualified_target)[0:2]
+
+        if input_file[-4:] != ".gyp":
+            continue
+        input_file_stem = input_file[:-4]
+        output_file = input_file_stem + params["options"].suffix + ".gypd"
+
+        output_files[output_file] = output_files.get(output_file, input_file)
+
+    for output_file, input_file in output_files.items():
+        output = open(output_file, "w")
+        pprint.pprint(data[input_file], output)
+        output.close()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/gypsh.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/gypsh.py
new file mode 100644
index 0000000..82a07dd
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/gypsh.py
@@ -0,0 +1,58 @@
+# Copyright (c) 2011 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""gypsh output module
+
+gypsh is a GYP shell.  It's not really a generator per se.  All it does is
+fire up an interactive Python session with a few local variables set to the
+variables passed to the generator.  Like gypd, it's intended as a debugging
+aid, to facilitate the exploration of .gyp structures after being processed
+by the input module.
+
+The expected usage is "gyp -f gypsh -D OS=desired_os".
+"""
+
+
+import code
+import sys
+
+
+# All of this stuff about generator variables was lovingly ripped from gypd.py.
+# That module has a much better description of what's going on and why.
+_generator_identity_variables = [
+    "EXECUTABLE_PREFIX",
+    "EXECUTABLE_SUFFIX",
+    "INTERMEDIATE_DIR",
+    "PRODUCT_DIR",
+    "RULE_INPUT_ROOT",
+    "RULE_INPUT_DIRNAME",
+    "RULE_INPUT_EXT",
+    "RULE_INPUT_NAME",
+    "RULE_INPUT_PATH",
+    "SHARED_INTERMEDIATE_DIR",
+]
+
+generator_default_variables = {}
+
+for v in _generator_identity_variables:
+    generator_default_variables[v] = "<(%s)" % v
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    locals = {
+        "target_list": target_list,
+        "target_dicts": target_dicts,
+        "data": data,
+    }
+
+    # Use a banner that looks like the stock Python one and like what
+    # code.interact uses by default, but tack on something to indicate what
+    # locals are available, and identify gypsh.
+    banner = "Python {} on {}\nlocals.keys() = {}\ngypsh".format(
+        sys.version,
+        sys.platform,
+        repr(sorted(locals.keys())),
+    )
+
+    code.interact(banner, local=locals)
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/make.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/make.py
new file mode 100644
index 0000000..c595f20
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/make.py
@@ -0,0 +1,2518 @@
+# Copyright (c) 2013 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Notes:
+#
+# This is all roughly based on the Makefile system used by the Linux
+# kernel, but is a non-recursive make -- we put the entire dependency
+# graph in front of make and let it figure it out.
+#
+# The code below generates a separate .mk file for each target, but
+# all are sourced by the top-level Makefile.  This means that all
+# variables in .mk-files clobber one another.  Be careful to use :=
+# where appropriate for immediate evaluation, and similarly to watch
+# that you're not relying on a variable value to last between different
+# .mk files.
+#
+# TODOs:
+#
+# Global settings and utility functions are currently stuffed in the
+# toplevel Makefile.  It may make sense to generate some .mk files on
+# the side to keep the files readable.
+
+
+import os
+import re
+import subprocess
+import gyp
+import gyp.common
+import gyp.xcode_emulation
+from gyp.common import GetEnvironFallback
+
+import hashlib
+
+generator_default_variables = {
+    "EXECUTABLE_PREFIX": "",
+    "EXECUTABLE_SUFFIX": "",
+    "STATIC_LIB_PREFIX": "lib",
+    "SHARED_LIB_PREFIX": "lib",
+    "STATIC_LIB_SUFFIX": ".a",
+    "INTERMEDIATE_DIR": "$(obj).$(TOOLSET)/$(TARGET)/geni",
+    "SHARED_INTERMEDIATE_DIR": "$(obj)/gen",
+    "PRODUCT_DIR": "$(builddir)",
+    "RULE_INPUT_ROOT": "%(INPUT_ROOT)s",  # This gets expanded by Python.
+    "RULE_INPUT_DIRNAME": "%(INPUT_DIRNAME)s",  # This gets expanded by Python.
+    "RULE_INPUT_PATH": "$(abspath $<)",
+    "RULE_INPUT_EXT": "$(suffix $<)",
+    "RULE_INPUT_NAME": "$(notdir $<)",
+    "CONFIGURATION_NAME": "$(BUILDTYPE)",
+}
+
+# Make supports multiple toolsets
+generator_supports_multiple_toolsets = True
+
+# Request sorted dependencies in the order from dependents to dependencies.
+generator_wants_sorted_dependencies = False
+
+# Placates pylint.
+generator_additional_non_configuration_keys = []
+generator_additional_path_sections = []
+generator_extra_sources_for_rules = []
+generator_filelist_paths = None
+
+
+def CalculateVariables(default_variables, params):
+    """Calculate additional variables for use in the build (called by gyp)."""
+    flavor = gyp.common.GetFlavor(params)
+    if flavor == "mac":
+        default_variables.setdefault("OS", "mac")
+        default_variables.setdefault("SHARED_LIB_SUFFIX", ".dylib")
+        default_variables.setdefault(
+            "SHARED_LIB_DIR", generator_default_variables["PRODUCT_DIR"]
+        )
+        default_variables.setdefault(
+            "LIB_DIR", generator_default_variables["PRODUCT_DIR"]
+        )
+
+        # Copy additional generator configuration data from Xcode, which is shared
+        # by the Mac Make generator.
+        import gyp.generator.xcode as xcode_generator
+
+        global generator_additional_non_configuration_keys
+        generator_additional_non_configuration_keys = getattr(
+            xcode_generator, "generator_additional_non_configuration_keys", []
+        )
+        global generator_additional_path_sections
+        generator_additional_path_sections = getattr(
+            xcode_generator, "generator_additional_path_sections", []
+        )
+        global generator_extra_sources_for_rules
+        generator_extra_sources_for_rules = getattr(
+            xcode_generator, "generator_extra_sources_for_rules", []
+        )
+        COMPILABLE_EXTENSIONS.update({".m": "objc", ".mm": "objcxx"})
+    else:
+        operating_system = flavor
+        if flavor == "android":
+            operating_system = "linux"  # Keep this legacy behavior for now.
+        default_variables.setdefault("OS", operating_system)
+        if flavor == "aix":
+            default_variables.setdefault("SHARED_LIB_SUFFIX", ".a")
+        else:
+            default_variables.setdefault("SHARED_LIB_SUFFIX", ".so")
+        default_variables.setdefault("SHARED_LIB_DIR", "$(builddir)/lib.$(TOOLSET)")
+        default_variables.setdefault("LIB_DIR", "$(obj).$(TOOLSET)")
+
+
+def CalculateGeneratorInputInfo(params):
+    """Calculate the generator specific info that gets fed to input (called by
+    gyp)."""
+    generator_flags = params.get("generator_flags", {})
+    android_ndk_version = generator_flags.get("android_ndk_version", None)
+    # Android NDK requires a strict link order.
+    if android_ndk_version:
+        global generator_wants_sorted_dependencies
+        generator_wants_sorted_dependencies = True
+
+    output_dir = params["options"].generator_output or params["options"].toplevel_dir
+    builddir_name = generator_flags.get("output_dir", "out")
+    qualified_out_dir = os.path.normpath(
+        os.path.join(output_dir, builddir_name, "gypfiles")
+    )
+
+    global generator_filelist_paths
+    generator_filelist_paths = {
+        "toplevel": params["options"].toplevel_dir,
+        "qualified_out_dir": qualified_out_dir,
+    }
+
+
+# The .d checking code below uses these functions:
+# wildcard, sort, foreach, shell, wordlist
+# wildcard can handle spaces, the rest can't.
+# Since I could find no way to make foreach work with spaces in filenames
+# correctly, the .d files have spaces replaced with another character. The .d
+# file for
+#     Chromium\ Framework.framework/foo
+# is for example
+#     out/Release/.deps/out/Release/Chromium?Framework.framework/foo
+# This is the replacement character.
+SPACE_REPLACEMENT = "?"
+
+
+LINK_COMMANDS_LINUX = """\
+quiet_cmd_alink = AR($(TOOLSET)) $@
+cmd_alink = rm -f $@ && $(AR.$(TOOLSET)) crs $@ $(filter %.o,$^)
+
+quiet_cmd_alink_thin = AR($(TOOLSET)) $@
+cmd_alink_thin = rm -f $@ && $(AR.$(TOOLSET)) crsT $@ $(filter %.o,$^)
+
+# Due to circular dependencies between libraries :(, we wrap the
+# special "figure out circular dependencies" flags around the entire
+# input list during linking.
+quiet_cmd_link = LINK($(TOOLSET)) $@
+cmd_link = $(LINK.$(TOOLSET)) -o $@ $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -Wl,--start-group $(LD_INPUTS) $(LIBS) -Wl,--end-group
+
+# We support two kinds of shared objects (.so):
+# 1) shared_library, which is just bundling together many dependent libraries
+# into a link line.
+# 2) loadable_module, which is generating a module intended for dlopen().
+#
+# They differ only slightly:
+# In the former case, we want to package all dependent code into the .so.
+# In the latter case, we want to package just the API exposed by the
+# outermost module.
+# This means shared_library uses --whole-archive, while loadable_module doesn't.
+# (Note that --whole-archive is incompatible with the --start-group used in
+# normal linking.)
+
+# Other shared-object link notes:
+# - Set SONAME to the library filename so our binaries don't reference
+# the local, absolute paths used on the link command-line.
+quiet_cmd_solink = SOLINK($(TOOLSET)) $@
+cmd_solink = $(LINK.$(TOOLSET)) -o $@ -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -Wl,-soname=$(@F) -Wl,--whole-archive $(LD_INPUTS) -Wl,--no-whole-archive $(LIBS)
+
+quiet_cmd_solink_module = SOLINK_MODULE($(TOOLSET)) $@
+cmd_solink_module = $(LINK.$(TOOLSET)) -o $@ -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -Wl,-soname=$(@F) -Wl,--start-group $(filter-out FORCE_DO_CMD, $^) -Wl,--end-group $(LIBS)
+"""  # noqa: E501
+
+LINK_COMMANDS_MAC = """\
+quiet_cmd_alink = LIBTOOL-STATIC $@
+cmd_alink = rm -f $@ && ./gyp-mac-tool filter-libtool libtool $(GYP_LIBTOOLFLAGS) -static -o $@ $(filter %.o,$^)
+
+quiet_cmd_link = LINK($(TOOLSET)) $@
+cmd_link = $(LINK.$(TOOLSET)) $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o "$@" $(LD_INPUTS) $(LIBS)
+
+quiet_cmd_solink = SOLINK($(TOOLSET)) $@
+cmd_solink = $(LINK.$(TOOLSET)) -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o "$@" $(LD_INPUTS) $(LIBS)
+
+quiet_cmd_solink_module = SOLINK_MODULE($(TOOLSET)) $@
+cmd_solink_module = $(LINK.$(TOOLSET)) -bundle $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o $@ $(filter-out FORCE_DO_CMD, $^) $(LIBS)
+"""  # noqa: E501
+
+LINK_COMMANDS_ANDROID = """\
+quiet_cmd_alink = AR($(TOOLSET)) $@
+cmd_alink = rm -f $@ && $(AR.$(TOOLSET)) crs $@ $(filter %.o,$^)
+
+quiet_cmd_alink_thin = AR($(TOOLSET)) $@
+cmd_alink_thin = rm -f $@ && $(AR.$(TOOLSET)) crsT $@ $(filter %.o,$^)
+
+# Due to circular dependencies between libraries :(, we wrap the
+# special "figure out circular dependencies" flags around the entire
+# input list during linking.
+quiet_cmd_link = LINK($(TOOLSET)) $@
+quiet_cmd_link_host = LINK($(TOOLSET)) $@
+cmd_link = $(LINK.$(TOOLSET)) $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o $@ -Wl,--start-group $(LD_INPUTS) -Wl,--end-group $(LIBS)
+cmd_link_host = $(LINK.$(TOOLSET)) $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o $@ -Wl,--start-group $(LD_INPUTS) -Wl,--end-group $(LIBS)
+
+# Other shared-object link notes:
+# - Set SONAME to the library filename so our binaries don't reference
+# the local, absolute paths used on the link command-line.
+quiet_cmd_solink = SOLINK($(TOOLSET)) $@
+cmd_solink = $(LINK.$(TOOLSET)) -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -Wl,-soname=$(@F) -o $@ -Wl,--whole-archive $(LD_INPUTS) -Wl,--no-whole-archive $(LIBS)
+
+quiet_cmd_solink_module = SOLINK_MODULE($(TOOLSET)) $@
+cmd_solink_module = $(LINK.$(TOOLSET)) -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -Wl,-soname=$(@F) -o $@ -Wl,--start-group $(filter-out FORCE_DO_CMD, $^) -Wl,--end-group $(LIBS)
+quiet_cmd_solink_module_host = SOLINK_MODULE($(TOOLSET)) $@
+cmd_solink_module_host = $(LINK.$(TOOLSET)) -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -Wl,-soname=$(@F) -o $@ $(filter-out FORCE_DO_CMD, $^) $(LIBS)
+"""  # noqa: E501
+
+
+LINK_COMMANDS_AIX = """\
+quiet_cmd_alink = AR($(TOOLSET)) $@
+cmd_alink = rm -f $@ && $(AR.$(TOOLSET)) -X32_64 crs $@ $(filter %.o,$^)
+
+quiet_cmd_alink_thin = AR($(TOOLSET)) $@
+cmd_alink_thin = rm -f $@ && $(AR.$(TOOLSET)) -X32_64 crs $@ $(filter %.o,$^)
+
+quiet_cmd_link = LINK($(TOOLSET)) $@
+cmd_link = $(LINK.$(TOOLSET)) $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o $@ $(LD_INPUTS) $(LIBS)
+
+quiet_cmd_solink = SOLINK($(TOOLSET)) $@
+cmd_solink = $(LINK.$(TOOLSET)) -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o $@ $(LD_INPUTS) $(LIBS)
+
+quiet_cmd_solink_module = SOLINK_MODULE($(TOOLSET)) $@
+cmd_solink_module = $(LINK.$(TOOLSET)) -shared $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o $@ $(filter-out FORCE_DO_CMD, $^) $(LIBS)
+"""  # noqa: E501
+
+
+LINK_COMMANDS_OS390 = """\
+quiet_cmd_alink = AR($(TOOLSET)) $@
+cmd_alink = rm -f $@ && $(AR.$(TOOLSET)) crs $@ $(filter %.o,$^)
+
+quiet_cmd_alink_thin = AR($(TOOLSET)) $@
+cmd_alink_thin = rm -f $@ && $(AR.$(TOOLSET)) crsT $@ $(filter %.o,$^)
+
+quiet_cmd_link = LINK($(TOOLSET)) $@
+cmd_link = $(LINK.$(TOOLSET)) $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o $@ $(LD_INPUTS) $(LIBS)
+
+quiet_cmd_solink = SOLINK($(TOOLSET)) $@
+cmd_solink = $(LINK.$(TOOLSET)) $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o $@ $(LD_INPUTS) $(LIBS) -Wl,DLL
+
+quiet_cmd_solink_module = SOLINK_MODULE($(TOOLSET)) $@
+cmd_solink_module = $(LINK.$(TOOLSET)) $(GYP_LDFLAGS) $(LDFLAGS.$(TOOLSET)) -o $@ $(filter-out FORCE_DO_CMD, $^) $(LIBS) -Wl,DLL
+"""  # noqa: E501
+
+
+# Header of toplevel Makefile.
+# This should go into the build tree, but it's easier to keep it here for now.
+SHARED_HEADER = (
+    """\
+# We borrow heavily from the kernel build setup, though we are simpler since
+# we don't have Kconfig tweaking settings on us.
+
+# The implicit make rules have it looking for RCS files, among other things.
+# We instead explicitly write all the rules we care about.
+# It's even quicker (saves ~200ms) to pass -r on the command line.
+MAKEFLAGS=-r
+
+# The source directory tree.
+srcdir := %(srcdir)s
+abs_srcdir := $(abspath $(srcdir))
+
+# The name of the builddir.
+builddir_name ?= %(builddir)s
+
+# The V=1 flag on command line makes us verbosely print command lines.
+ifdef V
+  quiet=
+else
+  quiet=quiet_
+endif
+
+# Specify BUILDTYPE=Release on the command line for a release build.
+BUILDTYPE ?= %(default_configuration)s
+
+# Directory all our build output goes into.
+# Note that this must be two directories beneath src/ for unit tests to pass,
+# as they reach into the src/ directory for data with relative paths.
+builddir ?= $(builddir_name)/$(BUILDTYPE)
+abs_builddir := $(abspath $(builddir))
+depsdir := $(builddir)/.deps
+
+# Object output directory.
+obj := $(builddir)/obj
+abs_obj := $(abspath $(obj))
+
+# We build up a list of every single one of the targets so we can slurp in the
+# generated dependency rule Makefiles in one pass.
+all_deps :=
+
+%(make_global_settings)s
+
+CC.target ?= %(CC.target)s
+CFLAGS.target ?= $(CPPFLAGS) $(CFLAGS)
+CXX.target ?= %(CXX.target)s
+CXXFLAGS.target ?= $(CPPFLAGS) $(CXXFLAGS)
+LINK.target ?= %(LINK.target)s
+LDFLAGS.target ?= $(LDFLAGS)
+AR.target ?= $(AR)
+
+# C++ apps need to be linked with g++.
+LINK ?= $(CXX.target)
+
+# TODO(evan): move all cross-compilation logic to gyp-time so we don't need
+# to replicate this environment fallback in make as well.
+CC.host ?= %(CC.host)s
+CFLAGS.host ?= $(CPPFLAGS_host) $(CFLAGS_host)
+CXX.host ?= %(CXX.host)s
+CXXFLAGS.host ?= $(CPPFLAGS_host) $(CXXFLAGS_host)
+LINK.host ?= %(LINK.host)s
+LDFLAGS.host ?= $(LDFLAGS_host)
+AR.host ?= %(AR.host)s
+
+# Define a dir function that can handle spaces.
+# http://www.gnu.org/software/make/manual/make.html#Syntax-of-Functions
+# "leading spaces cannot appear in the text of the first argument as written.
+# These characters can be put into the argument value by variable substitution."
+empty :=
+space := $(empty) $(empty)
+
+# http://stackoverflow.com/questions/1189781/using-make-dir-or-notdir-on-a-path-with-spaces
+replace_spaces = $(subst $(space),"""
+    + SPACE_REPLACEMENT
+    + """,$1)
+unreplace_spaces = $(subst """
+    + SPACE_REPLACEMENT
+    + """,$(space),$1)
+dirx = $(call unreplace_spaces,$(dir $(call replace_spaces,$1)))
+
+# Flags to make gcc output dependency info.  Note that you need to be
+# careful here to use the flags that ccache and distcc can understand.
+# We write to a dep file on the side first and then rename at the end
+# so we can't end up with a broken dep file.
+depfile = $(depsdir)/$(call replace_spaces,$@).d
+DEPFLAGS = %(makedep_args)s -MF $(depfile).raw
+
+# We have to fixup the deps output in a few ways.
+# (1) the file output should mention the proper .o file.
+# ccache or distcc lose the path to the target, so we convert a rule of
+# the form:
+#   foobar.o: DEP1 DEP2
+# into
+#   path/to/foobar.o: DEP1 DEP2
+# (2) we want missing files not to cause us to fail to build.
+# We want to rewrite
+#   foobar.o: DEP1 DEP2 \\
+#               DEP3
+# to
+#   DEP1:
+#   DEP2:
+#   DEP3:
+# so if the files are missing, they're just considered phony rules.
+# We have to do some pretty insane escaping to get those backslashes
+# and dollar signs past make, the shell, and sed at the same time.
+# Doesn't work with spaces, but that's fine: .d files have spaces in
+# their names replaced with other characters."""
+    r"""
+define fixup_dep
+# The depfile may not exist if the input file didn't have any #includes.
+touch $(depfile).raw
+# Fixup path as in (1).
+sed -e "s|^$(notdir $@)|$@|" $(depfile).raw >> $(depfile)
+# Add extra rules as in (2).
+# We remove slashes and replace spaces with new lines;
+# remove blank lines;
+# delete the first line and append a colon to the remaining lines.
+sed -e 's|\\||' -e 'y| |\n|' $(depfile).raw |\
+  grep -v '^$$'                             |\
+  sed -e 1d -e 's|$$|:|'                     \
+    >> $(depfile)
+rm $(depfile).raw
+endef
+"""
+    """
+# Command definitions:
+# - cmd_foo is the actual command to run;
+# - quiet_cmd_foo is the brief-output summary of the command.
+
+quiet_cmd_cc = CC($(TOOLSET)) $@
+cmd_cc = $(CC.$(TOOLSET)) -o $@ $< $(GYP_CFLAGS) $(DEPFLAGS) $(CFLAGS.$(TOOLSET)) -c
+
+quiet_cmd_cxx = CXX($(TOOLSET)) $@
+cmd_cxx = $(CXX.$(TOOLSET)) -o $@ $< $(GYP_CXXFLAGS) $(DEPFLAGS) $(CXXFLAGS.$(TOOLSET)) -c
+%(extra_commands)s
+quiet_cmd_touch = TOUCH $@
+cmd_touch = touch $@
+
+quiet_cmd_copy = COPY $@
+# send stderr to /dev/null to ignore messages when linking directories.
+cmd_copy = ln -f "$<" "$@" 2>/dev/null || (rm -rf "$@" && cp %(copy_archive_args)s "$<" "$@")
+
+%(link_commands)s
+"""  # noqa: E501
+    r"""
+# Define an escape_quotes function to escape single quotes.
+# This allows us to handle quotes properly as long as we always use
+# use single quotes and escape_quotes.
+escape_quotes = $(subst ','\'',$(1))
+# This comment is here just to include a ' to unconfuse syntax highlighting.
+# Define an escape_vars function to escape '$' variable syntax.
+# This allows us to read/write command lines with shell variables (e.g.
+# $LD_LIBRARY_PATH), without triggering make substitution.
+escape_vars = $(subst $$,$$$$,$(1))
+# Helper that expands to a shell command to echo a string exactly as it is in
+# make. This uses printf instead of echo because printf's behaviour with respect
+# to escape sequences is more portable than echo's across different shells
+# (e.g., dash, bash).
+exact_echo = printf '%%s\n' '$(call escape_quotes,$(1))'
+"""
+    """
+# Helper to compare the command we're about to run against the command
+# we logged the last time we ran the command.  Produces an empty
+# string (false) when the commands match.
+# Tricky point: Make has no string-equality test function.
+# The kernel uses the following, but it seems like it would have false
+# positives, where one string reordered its arguments.
+#   arg_check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \\
+#                       $(filter-out $(cmd_$@), $(cmd_$(1))))
+# We instead substitute each for the empty string into the other, and
+# say they're equal if both substitutions produce the empty string.
+# .d files contain """
+    + SPACE_REPLACEMENT
+    + """ instead of spaces, take that into account.
+command_changed = $(or $(subst $(cmd_$(1)),,$(cmd_$(call replace_spaces,$@))),\\
+                       $(subst $(cmd_$(call replace_spaces,$@)),,$(cmd_$(1))))
+
+# Helper that is non-empty when a prerequisite changes.
+# Normally make does this implicitly, but we force rules to always run
+# so we can check their command lines.
+#   $? -- new prerequisites
+#   $| -- order-only dependencies
+prereq_changed = $(filter-out FORCE_DO_CMD,$(filter-out $|,$?))
+
+# Helper that executes all postbuilds until one fails.
+define do_postbuilds
+  @E=0;\\
+  for p in $(POSTBUILDS); do\\
+    eval $$p;\\
+    E=$$?;\\
+    if [ $$E -ne 0 ]; then\\
+      break;\\
+    fi;\\
+  done;\\
+  if [ $$E -ne 0 ]; then\\
+    rm -rf "$@";\\
+    exit $$E;\\
+  fi
+endef
+
+# do_cmd: run a command via the above cmd_foo names, if necessary.
+# Should always run for a given target to handle command-line changes.
+# Second argument, if non-zero, makes it do asm/C/C++ dependency munging.
+# Third argument, if non-zero, makes it do POSTBUILDS processing.
+# Note: We intentionally do NOT call dirx for depfile, since it contains """
+    + SPACE_REPLACEMENT
+    + """ for
+# spaces already and dirx strips the """
+    + SPACE_REPLACEMENT
+    + """ characters.
+define do_cmd
+$(if $(or $(command_changed),$(prereq_changed)),
+  @$(call exact_echo,  $($(quiet)cmd_$(1)))
+  @mkdir -p "$(call dirx,$@)" "$(dir $(depfile))"
+  $(if $(findstring flock,$(word %(flock_index)d,$(cmd_$1))),
+    @$(cmd_$(1))
+    @echo "  $(quiet_cmd_$(1)): Finished",
+    @$(cmd_$(1))
+  )
+  @$(call exact_echo,$(call escape_vars,cmd_$(call replace_spaces,$@) := $(cmd_$(1)))) > $(depfile)
+  @$(if $(2),$(fixup_dep))
+  $(if $(and $(3), $(POSTBUILDS)),
+    $(call do_postbuilds)
+  )
+)
+endef
+
+# Declare the "%(default_target)s" target first so it is the default,
+# even though we don't have the deps yet.
+.PHONY: %(default_target)s
+%(default_target)s:
+
+# make looks for ways to re-generate included makefiles, but in our case, we
+# don't have a direct way. Explicitly telling make that it has nothing to do
+# for them makes it go faster.
+%%.d: ;
+
+# Use FORCE_DO_CMD to force a target to run.  Should be coupled with
+# do_cmd.
+.PHONY: FORCE_DO_CMD
+FORCE_DO_CMD:
+
+"""  # noqa: E501
+)
+
+SHARED_HEADER_MAC_COMMANDS = """
+quiet_cmd_objc = CXX($(TOOLSET)) $@
+cmd_objc = $(CC.$(TOOLSET)) $(GYP_OBJCFLAGS) $(DEPFLAGS) -c -o $@ $<
+
+quiet_cmd_objcxx = CXX($(TOOLSET)) $@
+cmd_objcxx = $(CXX.$(TOOLSET)) $(GYP_OBJCXXFLAGS) $(DEPFLAGS) -c -o $@ $<
+
+# Commands for precompiled header files.
+quiet_cmd_pch_c = CXX($(TOOLSET)) $@
+cmd_pch_c = $(CC.$(TOOLSET)) $(GYP_PCH_CFLAGS) $(DEPFLAGS) $(CXXFLAGS.$(TOOLSET)) -c -o $@ $<
+quiet_cmd_pch_cc = CXX($(TOOLSET)) $@
+cmd_pch_cc = $(CC.$(TOOLSET)) $(GYP_PCH_CXXFLAGS) $(DEPFLAGS) $(CXXFLAGS.$(TOOLSET)) -c -o $@ $<
+quiet_cmd_pch_m = CXX($(TOOLSET)) $@
+cmd_pch_m = $(CC.$(TOOLSET)) $(GYP_PCH_OBJCFLAGS) $(DEPFLAGS) -c -o $@ $<
+quiet_cmd_pch_mm = CXX($(TOOLSET)) $@
+cmd_pch_mm = $(CC.$(TOOLSET)) $(GYP_PCH_OBJCXXFLAGS) $(DEPFLAGS) -c -o $@ $<
+
+# gyp-mac-tool is written next to the root Makefile by gyp.
+# Use $(4) for the command, since $(2) and $(3) are used as flag by do_cmd
+# already.
+quiet_cmd_mac_tool = MACTOOL $(4) $<
+cmd_mac_tool = ./gyp-mac-tool $(4) $< "$@"
+
+quiet_cmd_mac_package_framework = PACKAGE FRAMEWORK $@
+cmd_mac_package_framework = ./gyp-mac-tool package-framework "$@" $(4)
+
+quiet_cmd_infoplist = INFOPLIST $@
+cmd_infoplist = $(CC.$(TOOLSET)) -E -P -Wno-trigraphs -x c $(INFOPLIST_DEFINES) "$<" -o "$@"
+"""  # noqa: E501
+
+
+def WriteRootHeaderSuffixRules(writer):
+    extensions = sorted(COMPILABLE_EXTENSIONS.keys(), key=str.lower)
+
+    writer.write("# Suffix rules, putting all outputs into $(obj).\n")
+    for ext in extensions:
+        writer.write("$(obj).$(TOOLSET)/%%.o: $(srcdir)/%%%s FORCE_DO_CMD\n" % ext)
+        writer.write("\t@$(call do_cmd,%s,1)\n" % COMPILABLE_EXTENSIONS[ext])
+
+    writer.write("\n# Try building from generated source, too.\n")
+    for ext in extensions:
+        writer.write(
+            "$(obj).$(TOOLSET)/%%.o: $(obj).$(TOOLSET)/%%%s FORCE_DO_CMD\n" % ext
+        )
+        writer.write("\t@$(call do_cmd,%s,1)\n" % COMPILABLE_EXTENSIONS[ext])
+    writer.write("\n")
+    for ext in extensions:
+        writer.write("$(obj).$(TOOLSET)/%%.o: $(obj)/%%%s FORCE_DO_CMD\n" % ext)
+        writer.write("\t@$(call do_cmd,%s,1)\n" % COMPILABLE_EXTENSIONS[ext])
+    writer.write("\n")
+
+
+SHARED_HEADER_SUFFIX_RULES_COMMENT1 = """\
+# Suffix rules, putting all outputs into $(obj).
+"""
+
+
+SHARED_HEADER_SUFFIX_RULES_COMMENT2 = """\
+# Try building from generated source, too.
+"""
+
+
+SHARED_FOOTER = """\
+# "all" is a concatenation of the "all" targets from all the included
+# sub-makefiles. This is just here to clarify.
+all:
+
+# Add in dependency-tracking rules.  $(all_deps) is the list of every single
+# target in our tree. Only consider the ones with .d (dependency) info:
+d_files := $(wildcard $(foreach f,$(all_deps),$(depsdir)/$(f).d))
+ifneq ($(d_files),)
+  include $(d_files)
+endif
+"""
+
+header = """\
+# This file is generated by gyp; do not edit.
+
+"""
+
+# Maps every compilable file extension to the do_cmd that compiles it.
+COMPILABLE_EXTENSIONS = {
+    ".c": "cc",
+    ".cc": "cxx",
+    ".cpp": "cxx",
+    ".cxx": "cxx",
+    ".s": "cc",
+    ".S": "cc",
+}
+
+
+def Compilable(filename):
+    """Return true if the file is compilable (should be in OBJS)."""
+    for res in (filename.endswith(e) for e in COMPILABLE_EXTENSIONS):
+        if res:
+            return True
+    return False
+
+
+def Linkable(filename):
+    """Return true if the file is linkable (should be on the link line)."""
+    return filename.endswith(".o")
+
+
+def Target(filename):
+    """Translate a compilable filename to its .o target."""
+    return os.path.splitext(filename)[0] + ".o"
+
+
+def EscapeShellArgument(s):
+    """Quotes an argument so that it will be interpreted literally by a POSIX
+    shell. Taken from
+    http://stackoverflow.com/questions/35817/whats-the-best-way-to-escape-ossystem-calls-in-python
+    """
+    return "'" + s.replace("'", "'\\''") + "'"
+
+
+def EscapeMakeVariableExpansion(s):
+    """Make has its own variable expansion syntax using $. We must escape it for
+    string to be interpreted literally."""
+    return s.replace("$", "$$")
+
+
+def EscapeCppDefine(s):
+    """Escapes a CPP define so that it will reach the compiler unaltered."""
+    s = EscapeShellArgument(s)
+    s = EscapeMakeVariableExpansion(s)
+    # '#' characters must be escaped even embedded in a string, else Make will
+    # treat it as the start of a comment.
+    return s.replace("#", r"\#")
+
+
+def QuoteIfNecessary(string):
+    """TODO: Should this ideally be replaced with one or more of the above
+    functions?"""
+    if '"' in string:
+        string = '"' + string.replace('"', '\\"') + '"'
+    return string
+
+
+def StringToMakefileVariable(string):
+    """Convert a string to a value that is acceptable as a make variable name."""
+    return re.sub("[^a-zA-Z0-9_]", "_", string)
+
+
+srcdir_prefix = ""
+
+
+def Sourceify(path):
+    """Convert a path to its source directory form."""
+    if "$(" in path:
+        return path
+    if os.path.isabs(path):
+        return path
+    return srcdir_prefix + path
+
+
+def QuoteSpaces(s, quote=r"\ "):
+    return s.replace(" ", quote)
+
+
+def SourceifyAndQuoteSpaces(path):
+    """Convert a path to its source directory form and quote spaces."""
+    return QuoteSpaces(Sourceify(path))
+
+
+# Map from qualified target to path to output.
+target_outputs = {}
+# Map from qualified target to any linkable output.  A subset
+# of target_outputs.  E.g. when mybinary depends on liba, we want to
+# include liba in the linker line; when otherbinary depends on
+# mybinary, we just want to build mybinary first.
+target_link_deps = {}
+
+
+class MakefileWriter:
+    """MakefileWriter packages up the writing of one target-specific foobar.mk.
+
+    Its only real entry point is Write(), and is mostly used for namespacing.
+    """
+
+    def __init__(self, generator_flags, flavor):
+        self.generator_flags = generator_flags
+        self.flavor = flavor
+
+        self.suffix_rules_srcdir = {}
+        self.suffix_rules_objdir1 = {}
+        self.suffix_rules_objdir2 = {}
+
+        # Generate suffix rules for all compilable extensions.
+        for ext in COMPILABLE_EXTENSIONS.keys():
+            # Suffix rules for source folder.
+            self.suffix_rules_srcdir.update(
+                {
+                    ext: (
+                        """\
+$(obj).$(TOOLSET)/$(TARGET)/%%.o: $(srcdir)/%%%s FORCE_DO_CMD
+\t@$(call do_cmd,%s,1)
+"""
+                        % (ext, COMPILABLE_EXTENSIONS[ext])
+                    )
+                }
+            )
+
+            # Suffix rules for generated source files.
+            self.suffix_rules_objdir1.update(
+                {
+                    ext: (
+                        """\
+$(obj).$(TOOLSET)/$(TARGET)/%%.o: $(obj).$(TOOLSET)/%%%s FORCE_DO_CMD
+\t@$(call do_cmd,%s,1)
+"""
+                        % (ext, COMPILABLE_EXTENSIONS[ext])
+                    )
+                }
+            )
+            self.suffix_rules_objdir2.update(
+                {
+                    ext: (
+                        """\
+$(obj).$(TOOLSET)/$(TARGET)/%%.o: $(obj)/%%%s FORCE_DO_CMD
+\t@$(call do_cmd,%s,1)
+"""
+                        % (ext, COMPILABLE_EXTENSIONS[ext])
+                    )
+                }
+            )
+
+    def Write(
+        self, qualified_target, base_path, output_filename, spec, configs, part_of_all
+    ):
+        """The main entry point: writes a .mk file for a single target.
+
+        Arguments:
+          qualified_target: target we're generating
+          base_path: path relative to source root we're building in, used to resolve
+                     target-relative paths
+          output_filename: output .mk file name to write
+          spec, configs: gyp info
+          part_of_all: flag indicating this target is part of 'all'
+        """
+        gyp.common.EnsureDirExists(output_filename)
+
+        self.fp = open(output_filename, "w")
+
+        self.fp.write(header)
+
+        self.qualified_target = qualified_target
+        self.path = base_path
+        self.target = spec["target_name"]
+        self.type = spec["type"]
+        self.toolset = spec["toolset"]
+
+        self.is_mac_bundle = gyp.xcode_emulation.IsMacBundle(self.flavor, spec)
+        if self.flavor == "mac":
+            self.xcode_settings = gyp.xcode_emulation.XcodeSettings(spec)
+        else:
+            self.xcode_settings = None
+
+        deps, link_deps = self.ComputeDeps(spec)
+
+        # Some of the generation below can add extra output, sources, or
+        # link dependencies.  All of the out params of the functions that
+        # follow use names like extra_foo.
+        extra_outputs = []
+        extra_sources = []
+        extra_link_deps = []
+        extra_mac_bundle_resources = []
+        mac_bundle_deps = []
+
+        if self.is_mac_bundle:
+            self.output = self.ComputeMacBundleOutput(spec)
+            self.output_binary = self.ComputeMacBundleBinaryOutput(spec)
+        else:
+            self.output = self.output_binary = self.ComputeOutput(spec)
+
+        self.is_standalone_static_library = bool(
+            spec.get("standalone_static_library", 0)
+        )
+        self._INSTALLABLE_TARGETS = ("executable", "loadable_module", "shared_library")
+        if self.is_standalone_static_library or self.type in self._INSTALLABLE_TARGETS:
+            self.alias = os.path.basename(self.output)
+            install_path = self._InstallableTargetInstallPath()
+        else:
+            self.alias = self.output
+            install_path = self.output
+
+        self.WriteLn("TOOLSET := " + self.toolset)
+        self.WriteLn("TARGET := " + self.target)
+
+        # Actions must come first, since they can generate more OBJs for use below.
+        if "actions" in spec:
+            self.WriteActions(
+                spec["actions"],
+                extra_sources,
+                extra_outputs,
+                extra_mac_bundle_resources,
+                part_of_all,
+            )
+
+        # Rules must be early like actions.
+        if "rules" in spec:
+            self.WriteRules(
+                spec["rules"],
+                extra_sources,
+                extra_outputs,
+                extra_mac_bundle_resources,
+                part_of_all,
+            )
+
+        if "copies" in spec:
+            self.WriteCopies(spec["copies"], extra_outputs, part_of_all)
+
+        # Bundle resources.
+        if self.is_mac_bundle:
+            all_mac_bundle_resources = (
+                spec.get("mac_bundle_resources", []) + extra_mac_bundle_resources
+            )
+            self.WriteMacBundleResources(all_mac_bundle_resources, mac_bundle_deps)
+            self.WriteMacInfoPlist(mac_bundle_deps)
+
+        # Sources.
+        all_sources = spec.get("sources", []) + extra_sources
+        if all_sources:
+            self.WriteSources(
+                configs,
+                deps,
+                all_sources,
+                extra_outputs,
+                extra_link_deps,
+                part_of_all,
+                gyp.xcode_emulation.MacPrefixHeader(
+                    self.xcode_settings,
+                    lambda p: Sourceify(self.Absolutify(p)),
+                    self.Pchify,
+                ),
+            )
+            sources = [x for x in all_sources if Compilable(x)]
+            if sources:
+                self.WriteLn(SHARED_HEADER_SUFFIX_RULES_COMMENT1)
+                extensions = {os.path.splitext(s)[1] for s in sources}
+                for ext in extensions:
+                    if ext in self.suffix_rules_srcdir:
+                        self.WriteLn(self.suffix_rules_srcdir[ext])
+                self.WriteLn(SHARED_HEADER_SUFFIX_RULES_COMMENT2)
+                for ext in extensions:
+                    if ext in self.suffix_rules_objdir1:
+                        self.WriteLn(self.suffix_rules_objdir1[ext])
+                for ext in extensions:
+                    if ext in self.suffix_rules_objdir2:
+                        self.WriteLn(self.suffix_rules_objdir2[ext])
+                self.WriteLn("# End of this set of suffix rules")
+
+                # Add dependency from bundle to bundle binary.
+                if self.is_mac_bundle:
+                    mac_bundle_deps.append(self.output_binary)
+
+        self.WriteTarget(
+            spec,
+            configs,
+            deps,
+            extra_link_deps + link_deps,
+            mac_bundle_deps,
+            extra_outputs,
+            part_of_all,
+        )
+
+        # Update global list of target outputs, used in dependency tracking.
+        target_outputs[qualified_target] = install_path
+
+        # Update global list of link dependencies.
+        if self.type in ("static_library", "shared_library"):
+            target_link_deps[qualified_target] = self.output_binary
+
+        # Currently any versions have the same effect, but in future the behavior
+        # could be different.
+        if self.generator_flags.get("android_ndk_version", None):
+            self.WriteAndroidNdkModuleRule(self.target, all_sources, link_deps)
+
+        self.fp.close()
+
+    def WriteSubMake(self, output_filename, makefile_path, targets, build_dir):
+        """Write a "sub-project" Makefile.
+
+        This is a small, wrapper Makefile that calls the top-level Makefile to build
+        the targets from a single gyp file (i.e. a sub-project).
+
+        Arguments:
+          output_filename: sub-project Makefile name to write
+          makefile_path: path to the top-level Makefile
+          targets: list of "all" targets for this sub-project
+          build_dir: build output directory, relative to the sub-project
+        """
+        gyp.common.EnsureDirExists(output_filename)
+        self.fp = open(output_filename, "w")
+        self.fp.write(header)
+        # For consistency with other builders, put sub-project build output in the
+        # sub-project dir (see test/subdirectory/gyptest-subdir-all.py).
+        self.WriteLn(
+            "export builddir_name ?= %s"
+            % os.path.join(os.path.dirname(output_filename), build_dir)
+        )
+        self.WriteLn(".PHONY: all")
+        self.WriteLn("all:")
+        if makefile_path:
+            makefile_path = " -C " + makefile_path
+        self.WriteLn("\t$(MAKE){} {}".format(makefile_path, " ".join(targets)))
+        self.fp.close()
+
+    def WriteActions(
+        self,
+        actions,
+        extra_sources,
+        extra_outputs,
+        extra_mac_bundle_resources,
+        part_of_all,
+    ):
+        """Write Makefile code for any 'actions' from the gyp input.
+
+        extra_sources: a list that will be filled in with newly generated source
+                       files, if any
+        extra_outputs: a list that will be filled in with any outputs of these
+                       actions (used to make other pieces dependent on these
+                       actions)
+        part_of_all: flag indicating this target is part of 'all'
+        """
+        env = self.GetSortedXcodeEnv()
+        for action in actions:
+            name = StringToMakefileVariable(
+                "{}_{}".format(self.qualified_target, action["action_name"])
+            )
+            self.WriteLn('### Rules for action "%s":' % action["action_name"])
+            inputs = action["inputs"]
+            outputs = action["outputs"]
+
+            # Build up a list of outputs.
+            # Collect the output dirs we'll need.
+            dirs = set()
+            for out in outputs:
+                dir = os.path.split(out)[0]
+                if dir:
+                    dirs.add(dir)
+            if int(action.get("process_outputs_as_sources", False)):
+                extra_sources += outputs
+            if int(action.get("process_outputs_as_mac_bundle_resources", False)):
+                extra_mac_bundle_resources += outputs
+
+            # Write the actual command.
+            action_commands = action["action"]
+            if self.flavor == "mac":
+                action_commands = [
+                    gyp.xcode_emulation.ExpandEnvVars(command, env)
+                    for command in action_commands
+                ]
+            command = gyp.common.EncodePOSIXShellList(action_commands)
+            if "message" in action:
+                self.WriteLn(
+                    "quiet_cmd_{} = ACTION {} $@".format(name, action["message"])
+                )
+            else:
+                self.WriteLn(f"quiet_cmd_{name} = ACTION {name} $@")
+            if len(dirs) > 0:
+                command = "mkdir -p %s" % " ".join(dirs) + "; " + command
+
+            cd_action = "cd %s; " % Sourceify(self.path or ".")
+
+            # command and cd_action get written to a toplevel variable called
+            # cmd_foo. Toplevel variables can't handle things that change per
+            # makefile like $(TARGET), so hardcode the target.
+            command = command.replace("$(TARGET)", self.target)
+            cd_action = cd_action.replace("$(TARGET)", self.target)
+
+            # Set LD_LIBRARY_PATH in case the action runs an executable from this
+            # build which links to shared libs from this build.
+            # actions run on the host, so they should in theory only use host
+            # libraries, but until everything is made cross-compile safe, also use
+            # target libraries.
+            # TODO(piman): when everything is cross-compile safe, remove lib.target
+            self.WriteLn(
+                "cmd_%s = LD_LIBRARY_PATH=$(builddir)/lib.host:"
+                "$(builddir)/lib.target:$$LD_LIBRARY_PATH; "
+                "export LD_LIBRARY_PATH; "
+                "%s%s" % (name, cd_action, command)
+            )
+            self.WriteLn()
+            outputs = [self.Absolutify(o) for o in outputs]
+            # The makefile rules are all relative to the top dir, but the gyp actions
+            # are defined relative to their containing dir.  This replaces the obj
+            # variable for the action rule with an absolute version so that the output
+            # goes in the right place.
+            # Only write the 'obj' and 'builddir' rules for the "primary" output (:1);
+            # it's superfluous for the "extra outputs", and this avoids accidentally
+            # writing duplicate dummy rules for those outputs.
+            # Same for environment.
+            self.WriteLn("%s: obj := $(abs_obj)" % QuoteSpaces(outputs[0]))
+            self.WriteLn("%s: builddir := $(abs_builddir)" % QuoteSpaces(outputs[0]))
+            self.WriteSortedXcodeEnv(outputs[0], self.GetSortedXcodeEnv())
+
+            for input in inputs:
+                assert " " not in input, (
+                    "Spaces in action input filenames not supported (%s)" % input
+                )
+            for output in outputs:
+                assert " " not in output, (
+                    "Spaces in action output filenames not supported (%s)" % output
+                )
+
+            # See the comment in WriteCopies about expanding env vars.
+            outputs = [gyp.xcode_emulation.ExpandEnvVars(o, env) for o in outputs]
+            inputs = [gyp.xcode_emulation.ExpandEnvVars(i, env) for i in inputs]
+
+            self.WriteDoCmd(
+                outputs,
+                [Sourceify(self.Absolutify(i)) for i in inputs],
+                part_of_all=part_of_all,
+                command=name,
+            )
+
+            # Stuff the outputs in a variable so we can refer to them later.
+            outputs_variable = "action_%s_outputs" % name
+            self.WriteLn("{} := {}".format(outputs_variable, " ".join(outputs)))
+            extra_outputs.append("$(%s)" % outputs_variable)
+            self.WriteLn()
+
+        self.WriteLn()
+
+    def WriteRules(
+        self,
+        rules,
+        extra_sources,
+        extra_outputs,
+        extra_mac_bundle_resources,
+        part_of_all,
+    ):
+        """Write Makefile code for any 'rules' from the gyp input.
+
+        extra_sources: a list that will be filled in with newly generated source
+                       files, if any
+        extra_outputs: a list that will be filled in with any outputs of these
+                       rules (used to make other pieces dependent on these rules)
+        part_of_all: flag indicating this target is part of 'all'
+        """
+        env = self.GetSortedXcodeEnv()
+        for rule in rules:
+            name = StringToMakefileVariable(
+                "{}_{}".format(self.qualified_target, rule["rule_name"])
+            )
+            count = 0
+            self.WriteLn("### Generated for rule %s:" % name)
+
+            all_outputs = []
+
+            for rule_source in rule.get("rule_sources", []):
+                dirs = set()
+                (rule_source_dirname, rule_source_basename) = os.path.split(rule_source)
+                (rule_source_root, rule_source_ext) = os.path.splitext(
+                    rule_source_basename
+                )
+
+                outputs = [
+                    self.ExpandInputRoot(out, rule_source_root, rule_source_dirname)
+                    for out in rule["outputs"]
+                ]
+
+                for out in outputs:
+                    dir = os.path.dirname(out)
+                    if dir:
+                        dirs.add(dir)
+                if int(rule.get("process_outputs_as_sources", False)):
+                    extra_sources += outputs
+                if int(rule.get("process_outputs_as_mac_bundle_resources", False)):
+                    extra_mac_bundle_resources += outputs
+                inputs = [
+                    Sourceify(self.Absolutify(i))
+                    for i in [rule_source] + rule.get("inputs", [])
+                ]
+                actions = ["$(call do_cmd,%s_%d)" % (name, count)]
+
+                if name == "resources_grit":
+                    # HACK: This is ugly.  Grit intentionally doesn't touch the
+                    # timestamp of its output file when the file doesn't change,
+                    # which is fine in hash-based dependency systems like scons
+                    # and forge, but not kosher in the make world.  After some
+                    # discussion, hacking around it here seems like the least
+                    # amount of pain.
+                    actions += ["@touch --no-create $@"]
+
+                # See the comment in WriteCopies about expanding env vars.
+                outputs = [gyp.xcode_emulation.ExpandEnvVars(o, env) for o in outputs]
+                inputs = [gyp.xcode_emulation.ExpandEnvVars(i, env) for i in inputs]
+
+                outputs = [self.Absolutify(o) for o in outputs]
+                all_outputs += outputs
+                # Only write the 'obj' and 'builddir' rules for the "primary" output
+                # (:1); it's superfluous for the "extra outputs", and this avoids
+                # accidentally writing duplicate dummy rules for those outputs.
+                self.WriteLn("%s: obj := $(abs_obj)" % outputs[0])
+                self.WriteLn("%s: builddir := $(abs_builddir)" % outputs[0])
+                self.WriteMakeRule(
+                    outputs, inputs, actions, command="%s_%d" % (name, count)
+                )
+                # Spaces in rule filenames are not supported, but rule variables have
+                # spaces in them (e.g. RULE_INPUT_PATH expands to '$(abspath $<)').
+                # The spaces within the variables are valid, so remove the variables
+                # before checking.
+                variables_with_spaces = re.compile(r"\$$[^ ]* \$<$")
+                for output in outputs:
+                    output = re.sub(variables_with_spaces, "", output)
+                    assert " " not in output, (
+                        "Spaces in rule filenames not yet supported (%s)" % output
+                    )
+                self.WriteLn("all_deps += %s" % " ".join(outputs))
+
+                action = [
+                    self.ExpandInputRoot(ac, rule_source_root, rule_source_dirname)
+                    for ac in rule["action"]
+                ]
+                mkdirs = ""
+                if len(dirs) > 0:
+                    mkdirs = "mkdir -p %s; " % " ".join(dirs)
+                cd_action = "cd %s; " % Sourceify(self.path or ".")
+
+                # action, cd_action, and mkdirs get written to a toplevel variable
+                # called cmd_foo. Toplevel variables can't handle things that change
+                # per makefile like $(TARGET), so hardcode the target.
+                if self.flavor == "mac":
+                    action = [
+                        gyp.xcode_emulation.ExpandEnvVars(command, env)
+                        for command in action
+                    ]
+                action = gyp.common.EncodePOSIXShellList(action)
+                action = action.replace("$(TARGET)", self.target)
+                cd_action = cd_action.replace("$(TARGET)", self.target)
+                mkdirs = mkdirs.replace("$(TARGET)", self.target)
+
+                # Set LD_LIBRARY_PATH in case the rule runs an executable from this
+                # build which links to shared libs from this build.
+                # rules run on the host, so they should in theory only use host
+                # libraries, but until everything is made cross-compile safe, also use
+                # target libraries.
+                # TODO(piman): when everything is cross-compile safe, remove lib.target
+                self.WriteLn(
+                    "cmd_%(name)s_%(count)d = LD_LIBRARY_PATH="
+                    "$(builddir)/lib.host:$(builddir)/lib.target:$$LD_LIBRARY_PATH; "
+                    "export LD_LIBRARY_PATH; "
+                    "%(cd_action)s%(mkdirs)s%(action)s"
+                    % {
+                        "action": action,
+                        "cd_action": cd_action,
+                        "count": count,
+                        "mkdirs": mkdirs,
+                        "name": name,
+                    }
+                )
+                self.WriteLn(
+                    "quiet_cmd_%(name)s_%(count)d = RULE %(name)s_%(count)d $@"
+                    % {"count": count, "name": name}
+                )
+                self.WriteLn()
+                count += 1
+
+            outputs_variable = "rule_%s_outputs" % name
+            self.WriteList(all_outputs, outputs_variable)
+            extra_outputs.append("$(%s)" % outputs_variable)
+
+            self.WriteLn("### Finished generating for rule: %s" % name)
+            self.WriteLn()
+        self.WriteLn("### Finished generating for all rules")
+        self.WriteLn("")
+
+    def WriteCopies(self, copies, extra_outputs, part_of_all):
+        """Write Makefile code for any 'copies' from the gyp input.
+
+        extra_outputs: a list that will be filled in with any outputs of this action
+                       (used to make other pieces dependent on this action)
+        part_of_all: flag indicating this target is part of 'all'
+        """
+        self.WriteLn("### Generated for copy rule.")
+
+        variable = StringToMakefileVariable(self.qualified_target + "_copies")
+        outputs = []
+        for copy in copies:
+            for path in copy["files"]:
+                # Absolutify() may call normpath, and will strip trailing slashes.
+                path = Sourceify(self.Absolutify(path))
+                filename = os.path.split(path)[1]
+                output = Sourceify(
+                    self.Absolutify(os.path.join(copy["destination"], filename))
+                )
+
+                # If the output path has variables in it, which happens in practice for
+                # 'copies', writing the environment as target-local doesn't work,
+                # because the variables are already needed for the target name.
+                # Copying the environment variables into global make variables doesn't
+                # work either, because then the .d files will potentially contain spaces
+                # after variable expansion, and .d file handling cannot handle spaces.
+                # As a workaround, manually expand variables at gyp time. Since 'copies'
+                # can't run scripts, there's no need to write the env then.
+                # WriteDoCmd() will escape spaces for .d files.
+                env = self.GetSortedXcodeEnv()
+                output = gyp.xcode_emulation.ExpandEnvVars(output, env)
+                path = gyp.xcode_emulation.ExpandEnvVars(path, env)
+                self.WriteDoCmd([output], [path], "copy", part_of_all)
+                outputs.append(output)
+        self.WriteLn(
+            "{} = {}".format(variable, " ".join(QuoteSpaces(o) for o in outputs))
+        )
+        extra_outputs.append("$(%s)" % variable)
+        self.WriteLn()
+
+    def WriteMacBundleResources(self, resources, bundle_deps):
+        """Writes Makefile code for 'mac_bundle_resources'."""
+        self.WriteLn("### Generated for mac_bundle_resources")
+
+        for output, res in gyp.xcode_emulation.GetMacBundleResources(
+            generator_default_variables["PRODUCT_DIR"],
+            self.xcode_settings,
+            [Sourceify(self.Absolutify(r)) for r in resources],
+        ):
+            _, ext = os.path.splitext(output)
+            if ext != ".xcassets":
+                # Make does not supports '.xcassets' emulation.
+                self.WriteDoCmd(
+                    [output], [res], "mac_tool,,,copy-bundle-resource", part_of_all=True
+                )
+                bundle_deps.append(output)
+
+    def WriteMacInfoPlist(self, bundle_deps):
+        """Write Makefile code for bundle Info.plist files."""
+        info_plist, out, defines, extra_env = gyp.xcode_emulation.GetMacInfoPlist(
+            generator_default_variables["PRODUCT_DIR"],
+            self.xcode_settings,
+            lambda p: Sourceify(self.Absolutify(p)),
+        )
+        if not info_plist:
+            return
+        if defines:
+            # Create an intermediate file to store preprocessed results.
+            intermediate_plist = "$(obj).$(TOOLSET)/$(TARGET)/" + os.path.basename(
+                info_plist
+            )
+            self.WriteList(
+                defines,
+                intermediate_plist + ": INFOPLIST_DEFINES",
+                "-D",
+                quoter=EscapeCppDefine,
+            )
+            self.WriteMakeRule(
+                [intermediate_plist],
+                [info_plist],
+                [
+                    "$(call do_cmd,infoplist)",
+                    # "Convert" the plist so that any weird whitespace changes from the
+                    # preprocessor do not affect the XML parser in mac_tool.
+                    "@plutil -convert xml1 $@ $@",
+                ],
+            )
+            info_plist = intermediate_plist
+        # plists can contain envvars and substitute them into the file.
+        self.WriteSortedXcodeEnv(
+            out, self.GetSortedXcodeEnv(additional_settings=extra_env)
+        )
+        self.WriteDoCmd(
+            [out], [info_plist], "mac_tool,,,copy-info-plist", part_of_all=True
+        )
+        bundle_deps.append(out)
+
+    def WriteSources(
+        self,
+        configs,
+        deps,
+        sources,
+        extra_outputs,
+        extra_link_deps,
+        part_of_all,
+        precompiled_header,
+    ):
+        """Write Makefile code for any 'sources' from the gyp input.
+        These are source files necessary to build the current target.
+
+        configs, deps, sources: input from gyp.
+        extra_outputs: a list of extra outputs this action should be dependent on;
+                       used to serialize action/rules before compilation
+        extra_link_deps: a list that will be filled in with any outputs of
+                         compilation (to be used in link lines)
+        part_of_all: flag indicating this target is part of 'all'
+        """
+
+        # Write configuration-specific variables for CFLAGS, etc.
+        for configname in sorted(configs.keys()):
+            config = configs[configname]
+            self.WriteList(
+                config.get("defines"),
+                "DEFS_%s" % configname,
+                prefix="-D",
+                quoter=EscapeCppDefine,
+            )
+
+            if self.flavor == "mac":
+                cflags = self.xcode_settings.GetCflags(
+                    configname, arch=config.get("xcode_configuration_platform")
+                )
+                cflags_c = self.xcode_settings.GetCflagsC(configname)
+                cflags_cc = self.xcode_settings.GetCflagsCC(configname)
+                cflags_objc = self.xcode_settings.GetCflagsObjC(configname)
+                cflags_objcc = self.xcode_settings.GetCflagsObjCC(configname)
+            else:
+                cflags = config.get("cflags")
+                cflags_c = config.get("cflags_c")
+                cflags_cc = config.get("cflags_cc")
+
+            self.WriteLn("# Flags passed to all source files.")
+            self.WriteList(cflags, "CFLAGS_%s" % configname)
+            self.WriteLn("# Flags passed to only C files.")
+            self.WriteList(cflags_c, "CFLAGS_C_%s" % configname)
+            self.WriteLn("# Flags passed to only C++ files.")
+            self.WriteList(cflags_cc, "CFLAGS_CC_%s" % configname)
+            if self.flavor == "mac":
+                self.WriteLn("# Flags passed to only ObjC files.")
+                self.WriteList(cflags_objc, "CFLAGS_OBJC_%s" % configname)
+                self.WriteLn("# Flags passed to only ObjC++ files.")
+                self.WriteList(cflags_objcc, "CFLAGS_OBJCC_%s" % configname)
+            includes = config.get("include_dirs")
+            if includes:
+                includes = [Sourceify(self.Absolutify(i)) for i in includes]
+            self.WriteList(includes, "INCS_%s" % configname, prefix="-I")
+
+        compilable = list(filter(Compilable, sources))
+        objs = [self.Objectify(self.Absolutify(Target(c))) for c in compilable]
+        self.WriteList(objs, "OBJS")
+
+        for obj in objs:
+            assert " " not in obj, "Spaces in object filenames not supported (%s)" % obj
+        self.WriteLn(
+            "# Add to the list of files we specially track " "dependencies for."
+        )
+        self.WriteLn("all_deps += $(OBJS)")
+        self.WriteLn()
+
+        # Make sure our dependencies are built first.
+        if deps:
+            self.WriteMakeRule(
+                ["$(OBJS)"],
+                deps,
+                comment="Make sure our dependencies are built " "before any of us.",
+                order_only=True,
+            )
+
+        # Make sure the actions and rules run first.
+        # If they generate any extra headers etc., the per-.o file dep tracking
+        # will catch the proper rebuilds, so order only is still ok here.
+        if extra_outputs:
+            self.WriteMakeRule(
+                ["$(OBJS)"],
+                extra_outputs,
+                comment="Make sure our actions/rules run " "before any of us.",
+                order_only=True,
+            )
+
+        pchdeps = precompiled_header.GetObjDependencies(compilable, objs)
+        if pchdeps:
+            self.WriteLn("# Dependencies from obj files to their precompiled headers")
+            for source, obj, gch in pchdeps:
+                self.WriteLn(f"{obj}: {gch}")
+            self.WriteLn("# End precompiled header dependencies")
+
+        if objs:
+            extra_link_deps.append("$(OBJS)")
+            self.WriteLn(
+                """\
+# CFLAGS et al overrides must be target-local.
+# See "Target-specific Variable Values" in the GNU Make manual."""
+            )
+            self.WriteLn("$(OBJS): TOOLSET := $(TOOLSET)")
+            self.WriteLn(
+                "$(OBJS): GYP_CFLAGS := "
+                "$(DEFS_$(BUILDTYPE)) "
+                "$(INCS_$(BUILDTYPE)) "
+                "%s " % precompiled_header.GetInclude("c") + "$(CFLAGS_$(BUILDTYPE)) "
+                "$(CFLAGS_C_$(BUILDTYPE))"
+            )
+            self.WriteLn(
+                "$(OBJS): GYP_CXXFLAGS := "
+                "$(DEFS_$(BUILDTYPE)) "
+                "$(INCS_$(BUILDTYPE)) "
+                "%s " % precompiled_header.GetInclude("cc") + "$(CFLAGS_$(BUILDTYPE)) "
+                "$(CFLAGS_CC_$(BUILDTYPE))"
+            )
+            if self.flavor == "mac":
+                self.WriteLn(
+                    "$(OBJS): GYP_OBJCFLAGS := "
+                    "$(DEFS_$(BUILDTYPE)) "
+                    "$(INCS_$(BUILDTYPE)) "
+                    "%s " % precompiled_header.GetInclude("m")
+                    + "$(CFLAGS_$(BUILDTYPE)) "
+                    "$(CFLAGS_C_$(BUILDTYPE)) "
+                    "$(CFLAGS_OBJC_$(BUILDTYPE))"
+                )
+                self.WriteLn(
+                    "$(OBJS): GYP_OBJCXXFLAGS := "
+                    "$(DEFS_$(BUILDTYPE)) "
+                    "$(INCS_$(BUILDTYPE)) "
+                    "%s " % precompiled_header.GetInclude("mm")
+                    + "$(CFLAGS_$(BUILDTYPE)) "
+                    "$(CFLAGS_CC_$(BUILDTYPE)) "
+                    "$(CFLAGS_OBJCC_$(BUILDTYPE))"
+                )
+
+        self.WritePchTargets(precompiled_header.GetPchBuildCommands())
+
+        # If there are any object files in our input file list, link them into our
+        # output.
+        extra_link_deps += [source for source in sources if Linkable(source)]
+
+        self.WriteLn()
+
+    def WritePchTargets(self, pch_commands):
+        """Writes make rules to compile prefix headers."""
+        if not pch_commands:
+            return
+
+        for gch, lang_flag, lang, input in pch_commands:
+            extra_flags = {
+                "c": "$(CFLAGS_C_$(BUILDTYPE))",
+                "cc": "$(CFLAGS_CC_$(BUILDTYPE))",
+                "m": "$(CFLAGS_C_$(BUILDTYPE)) $(CFLAGS_OBJC_$(BUILDTYPE))",
+                "mm": "$(CFLAGS_CC_$(BUILDTYPE)) $(CFLAGS_OBJCC_$(BUILDTYPE))",
+            }[lang]
+            var_name = {
+                "c": "GYP_PCH_CFLAGS",
+                "cc": "GYP_PCH_CXXFLAGS",
+                "m": "GYP_PCH_OBJCFLAGS",
+                "mm": "GYP_PCH_OBJCXXFLAGS",
+            }[lang]
+            self.WriteLn(
+                f"{gch}: {var_name} := {lang_flag} " + "$(DEFS_$(BUILDTYPE)) "
+                "$(INCS_$(BUILDTYPE)) "
+                "$(CFLAGS_$(BUILDTYPE)) " + extra_flags
+            )
+
+            self.WriteLn(f"{gch}: {input} FORCE_DO_CMD")
+            self.WriteLn("\t@$(call do_cmd,pch_%s,1)" % lang)
+            self.WriteLn("")
+            assert " " not in gch, "Spaces in gch filenames not supported (%s)" % gch
+            self.WriteLn("all_deps += %s" % gch)
+            self.WriteLn("")
+
+    def ComputeOutputBasename(self, spec):
+        """Return the 'output basename' of a gyp spec.
+
+        E.g., the loadable module 'foobar' in directory 'baz' will produce
+          'libfoobar.so'
+        """
+        assert not self.is_mac_bundle
+
+        if self.flavor == "mac" and self.type in (
+            "static_library",
+            "executable",
+            "shared_library",
+            "loadable_module",
+        ):
+            return self.xcode_settings.GetExecutablePath()
+
+        target = spec["target_name"]
+        target_prefix = ""
+        target_ext = ""
+        if self.type == "static_library":
+            if target[:3] == "lib":
+                target = target[3:]
+            target_prefix = "lib"
+            target_ext = ".a"
+        elif self.type in ("loadable_module", "shared_library"):
+            if target[:3] == "lib":
+                target = target[3:]
+            target_prefix = "lib"
+            if self.flavor == "aix":
+                target_ext = ".a"
+            else:
+                target_ext = ".so"
+        elif self.type == "none":
+            target = "%s.stamp" % target
+        elif self.type != "executable":
+            print(
+                "ERROR: What output file should be generated?",
+                "type",
+                self.type,
+                "target",
+                target,
+            )
+
+        target_prefix = spec.get("product_prefix", target_prefix)
+        target = spec.get("product_name", target)
+        product_ext = spec.get("product_extension")
+        if product_ext:
+            target_ext = "." + product_ext
+
+        return target_prefix + target + target_ext
+
+    def _InstallImmediately(self):
+        return (
+            self.toolset == "target"
+            and self.flavor == "mac"
+            and self.type
+            in ("static_library", "executable", "shared_library", "loadable_module")
+        )
+
+    def ComputeOutput(self, spec):
+        """Return the 'output' (full output path) of a gyp spec.
+
+        E.g., the loadable module 'foobar' in directory 'baz' will produce
+          '$(obj)/baz/libfoobar.so'
+        """
+        assert not self.is_mac_bundle
+
+        path = os.path.join("$(obj)." + self.toolset, self.path)
+        if self.type == "executable" or self._InstallImmediately():
+            path = "$(builddir)"
+        path = spec.get("product_dir", path)
+        return os.path.join(path, self.ComputeOutputBasename(spec))
+
+    def ComputeMacBundleOutput(self, spec):
+        """Return the 'output' (full output path) to a bundle output directory."""
+        assert self.is_mac_bundle
+        path = generator_default_variables["PRODUCT_DIR"]
+        return os.path.join(path, self.xcode_settings.GetWrapperName())
+
+    def ComputeMacBundleBinaryOutput(self, spec):
+        """Return the 'output' (full output path) to the binary in a bundle."""
+        path = generator_default_variables["PRODUCT_DIR"]
+        return os.path.join(path, self.xcode_settings.GetExecutablePath())
+
+    def ComputeDeps(self, spec):
+        """Compute the dependencies of a gyp spec.
+
+        Returns a tuple (deps, link_deps), where each is a list of
+        filenames that will need to be put in front of make for either
+        building (deps) or linking (link_deps).
+        """
+        deps = []
+        link_deps = []
+        if "dependencies" in spec:
+            deps.extend(
+                [
+                    target_outputs[dep]
+                    for dep in spec["dependencies"]
+                    if target_outputs[dep]
+                ]
+            )
+            for dep in spec["dependencies"]:
+                if dep in target_link_deps:
+                    link_deps.append(target_link_deps[dep])
+            deps.extend(link_deps)
+            # TODO: It seems we need to transitively link in libraries (e.g. -lfoo)?
+            # This hack makes it work:
+            # link_deps.extend(spec.get('libraries', []))
+        return (gyp.common.uniquer(deps), gyp.common.uniquer(link_deps))
+
+    def WriteDependencyOnExtraOutputs(self, target, extra_outputs):
+        self.WriteMakeRule(
+            [self.output_binary],
+            extra_outputs,
+            comment="Build our special outputs first.",
+            order_only=True,
+        )
+
+    def WriteTarget(
+        self, spec, configs, deps, link_deps, bundle_deps, extra_outputs, part_of_all
+    ):
+        """Write Makefile code to produce the final target of the gyp spec.
+
+        spec, configs: input from gyp.
+        deps, link_deps: dependency lists; see ComputeDeps()
+        extra_outputs: any extra outputs that our target should depend on
+        part_of_all: flag indicating this target is part of 'all'
+        """
+
+        self.WriteLn("### Rules for final target.")
+
+        if extra_outputs:
+            self.WriteDependencyOnExtraOutputs(self.output_binary, extra_outputs)
+            self.WriteMakeRule(
+                extra_outputs,
+                deps,
+                comment=("Preserve order dependency of " "special output on deps."),
+                order_only=True,
+            )
+
+        target_postbuilds = {}
+        if self.type != "none":
+            for configname in sorted(configs.keys()):
+                config = configs[configname]
+                if self.flavor == "mac":
+                    ldflags = self.xcode_settings.GetLdflags(
+                        configname,
+                        generator_default_variables["PRODUCT_DIR"],
+                        lambda p: Sourceify(self.Absolutify(p)),
+                        arch=config.get("xcode_configuration_platform"),
+                    )
+
+                    # TARGET_POSTBUILDS_$(BUILDTYPE) is added to postbuilds later on.
+                    gyp_to_build = gyp.common.InvertRelativePath(self.path)
+                    target_postbuild = self.xcode_settings.AddImplicitPostbuilds(
+                        configname,
+                        QuoteSpaces(
+                            os.path.normpath(os.path.join(gyp_to_build, self.output))
+                        ),
+                        QuoteSpaces(
+                            os.path.normpath(
+                                os.path.join(gyp_to_build, self.output_binary)
+                            )
+                        ),
+                    )
+                    if target_postbuild:
+                        target_postbuilds[configname] = target_postbuild
+                else:
+                    ldflags = config.get("ldflags", [])
+                    # Compute an rpath for this output if needed.
+                    if any(dep.endswith(".so") or ".so." in dep for dep in deps):
+                        # We want to get the literal string "$ORIGIN"
+                        # into the link command, so we need lots of escaping.
+                        ldflags.append(r"-Wl,-rpath=\$$ORIGIN/")
+                        ldflags.append(r"-Wl,-rpath-link=\$(builddir)/")
+                library_dirs = config.get("library_dirs", [])
+                ldflags += [("-L%s" % library_dir) for library_dir in library_dirs]
+                self.WriteList(ldflags, "LDFLAGS_%s" % configname)
+                if self.flavor == "mac":
+                    self.WriteList(
+                        self.xcode_settings.GetLibtoolflags(configname),
+                        "LIBTOOLFLAGS_%s" % configname,
+                    )
+            libraries = spec.get("libraries")
+            if libraries:
+                # Remove duplicate entries
+                libraries = gyp.common.uniquer(libraries)
+                if self.flavor == "mac":
+                    libraries = self.xcode_settings.AdjustLibraries(libraries)
+            self.WriteList(libraries, "LIBS")
+            self.WriteLn(
+                "%s: GYP_LDFLAGS := $(LDFLAGS_$(BUILDTYPE))"
+                % QuoteSpaces(self.output_binary)
+            )
+            self.WriteLn("%s: LIBS := $(LIBS)" % QuoteSpaces(self.output_binary))
+
+            if self.flavor == "mac":
+                self.WriteLn(
+                    "%s: GYP_LIBTOOLFLAGS := $(LIBTOOLFLAGS_$(BUILDTYPE))"
+                    % QuoteSpaces(self.output_binary)
+                )
+
+        # Postbuild actions. Like actions, but implicitly depend on the target's
+        # output.
+        postbuilds = []
+        if self.flavor == "mac":
+            if target_postbuilds:
+                postbuilds.append("$(TARGET_POSTBUILDS_$(BUILDTYPE))")
+            postbuilds.extend(gyp.xcode_emulation.GetSpecPostbuildCommands(spec))
+
+        if postbuilds:
+            # Envvars may be referenced by TARGET_POSTBUILDS_$(BUILDTYPE),
+            # so we must output its definition first, since we declare variables
+            # using ":=".
+            self.WriteSortedXcodeEnv(self.output, self.GetSortedXcodePostbuildEnv())
+
+            for configname in target_postbuilds:
+                self.WriteLn(
+                    "%s: TARGET_POSTBUILDS_%s := %s"
+                    % (
+                        QuoteSpaces(self.output),
+                        configname,
+                        gyp.common.EncodePOSIXShellList(target_postbuilds[configname]),
+                    )
+                )
+
+            # Postbuilds expect to be run in the gyp file's directory, so insert an
+            # implicit postbuild to cd to there.
+            postbuilds.insert(0, gyp.common.EncodePOSIXShellList(["cd", self.path]))
+            for i, postbuild in enumerate(postbuilds):
+                if not postbuild.startswith("$"):
+                    postbuilds[i] = EscapeShellArgument(postbuild)
+            self.WriteLn("%s: builddir := $(abs_builddir)" % QuoteSpaces(self.output))
+            self.WriteLn(
+                "%s: POSTBUILDS := %s"
+                % (QuoteSpaces(self.output), " ".join(postbuilds))
+            )
+
+        # A bundle directory depends on its dependencies such as bundle resources
+        # and bundle binary. When all dependencies have been built, the bundle
+        # needs to be packaged.
+        if self.is_mac_bundle:
+            # If the framework doesn't contain a binary, then nothing depends
+            # on the actions -- make the framework depend on them directly too.
+            self.WriteDependencyOnExtraOutputs(self.output, extra_outputs)
+
+            # Bundle dependencies. Note that the code below adds actions to this
+            # target, so if you move these two lines, move the lines below as well.
+            self.WriteList([QuoteSpaces(dep) for dep in bundle_deps], "BUNDLE_DEPS")
+            self.WriteLn("%s: $(BUNDLE_DEPS)" % QuoteSpaces(self.output))
+
+            # After the framework is built, package it. Needs to happen before
+            # postbuilds, since postbuilds depend on this.
+            if self.type in ("shared_library", "loadable_module"):
+                self.WriteLn(
+                    "\t@$(call do_cmd,mac_package_framework,,,%s)"
+                    % self.xcode_settings.GetFrameworkVersion()
+                )
+
+            # Bundle postbuilds can depend on the whole bundle, so run them after
+            # the bundle is packaged, not already after the bundle binary is done.
+            if postbuilds:
+                self.WriteLn("\t@$(call do_postbuilds)")
+            postbuilds = []  # Don't write postbuilds for target's output.
+
+            # Needed by test/mac/gyptest-rebuild.py.
+            self.WriteLn("\t@true  # No-op, used by tests")
+
+            # Since this target depends on binary and resources which are in
+            # nested subfolders, the framework directory will be older than
+            # its dependencies usually. To prevent this rule from executing
+            # on every build (expensive, especially with postbuilds), expliclity
+            # update the time on the framework directory.
+            self.WriteLn("\t@touch -c %s" % QuoteSpaces(self.output))
+
+        if postbuilds:
+            assert not self.is_mac_bundle, (
+                "Postbuilds for bundles should be done "
+                "on the bundle, not the binary (target '%s')" % self.target
+            )
+            assert "product_dir" not in spec, (
+                "Postbuilds do not work with " "custom product_dir"
+            )
+
+        if self.type == "executable":
+            self.WriteLn(
+                "%s: LD_INPUTS := %s"
+                % (
+                    QuoteSpaces(self.output_binary),
+                    " ".join(QuoteSpaces(dep) for dep in link_deps),
+                )
+            )
+            if self.toolset == "host" and self.flavor == "android":
+                self.WriteDoCmd(
+                    [self.output_binary],
+                    link_deps,
+                    "link_host",
+                    part_of_all,
+                    postbuilds=postbuilds,
+                )
+            else:
+                self.WriteDoCmd(
+                    [self.output_binary],
+                    link_deps,
+                    "link",
+                    part_of_all,
+                    postbuilds=postbuilds,
+                )
+
+        elif self.type == "static_library":
+            for link_dep in link_deps:
+                assert " " not in link_dep, (
+                    "Spaces in alink input filenames not supported (%s)" % link_dep
+                )
+            if (
+                self.flavor not in ("mac", "openbsd", "netbsd", "win")
+                and not self.is_standalone_static_library
+            ):
+                self.WriteDoCmd(
+                    [self.output_binary],
+                    link_deps,
+                    "alink_thin",
+                    part_of_all,
+                    postbuilds=postbuilds,
+                )
+            else:
+                self.WriteDoCmd(
+                    [self.output_binary],
+                    link_deps,
+                    "alink",
+                    part_of_all,
+                    postbuilds=postbuilds,
+                )
+        elif self.type == "shared_library":
+            self.WriteLn(
+                "%s: LD_INPUTS := %s"
+                % (
+                    QuoteSpaces(self.output_binary),
+                    " ".join(QuoteSpaces(dep) for dep in link_deps),
+                )
+            )
+            self.WriteDoCmd(
+                [self.output_binary],
+                link_deps,
+                "solink",
+                part_of_all,
+                postbuilds=postbuilds,
+            )
+        elif self.type == "loadable_module":
+            for link_dep in link_deps:
+                assert " " not in link_dep, (
+                    "Spaces in module input filenames not supported (%s)" % link_dep
+                )
+            if self.toolset == "host" and self.flavor == "android":
+                self.WriteDoCmd(
+                    [self.output_binary],
+                    link_deps,
+                    "solink_module_host",
+                    part_of_all,
+                    postbuilds=postbuilds,
+                )
+            else:
+                self.WriteDoCmd(
+                    [self.output_binary],
+                    link_deps,
+                    "solink_module",
+                    part_of_all,
+                    postbuilds=postbuilds,
+                )
+        elif self.type == "none":
+            # Write a stamp line.
+            self.WriteDoCmd(
+                [self.output_binary], deps, "touch", part_of_all, postbuilds=postbuilds
+            )
+        else:
+            print("WARNING: no output for", self.type, self.target)
+
+        # Add an alias for each target (if there are any outputs).
+        # Installable target aliases are created below.
+        if (self.output and self.output != self.target) and (
+            self.type not in self._INSTALLABLE_TARGETS
+        ):
+            self.WriteMakeRule(
+                [self.target], [self.output], comment="Add target alias", phony=True
+            )
+            if part_of_all:
+                self.WriteMakeRule(
+                    ["all"],
+                    [self.target],
+                    comment='Add target alias to "all" target.',
+                    phony=True,
+                )
+
+        # Add special-case rules for our installable targets.
+        # 1) They need to install to the build dir or "product" dir.
+        # 2) They get shortcuts for building (e.g. "make chrome").
+        # 3) They are part of "make all".
+        if self.type in self._INSTALLABLE_TARGETS or self.is_standalone_static_library:
+            if self.type == "shared_library":
+                file_desc = "shared library"
+            elif self.type == "static_library":
+                file_desc = "static library"
+            else:
+                file_desc = "executable"
+            install_path = self._InstallableTargetInstallPath()
+            installable_deps = [self.output]
+            if (
+                self.flavor == "mac"
+                and "product_dir" not in spec
+                and self.toolset == "target"
+            ):
+                # On mac, products are created in install_path immediately.
+                assert install_path == self.output, "{} != {}".format(
+                    install_path,
+                    self.output,
+                )
+
+            # Point the target alias to the final binary output.
+            self.WriteMakeRule(
+                [self.target], [install_path], comment="Add target alias", phony=True
+            )
+            if install_path != self.output:
+                assert not self.is_mac_bundle  # See comment a few lines above.
+                self.WriteDoCmd(
+                    [install_path],
+                    [self.output],
+                    "copy",
+                    comment="Copy this to the %s output path." % file_desc,
+                    part_of_all=part_of_all,
+                )
+                installable_deps.append(install_path)
+            if self.output != self.alias and self.alias != self.target:
+                self.WriteMakeRule(
+                    [self.alias],
+                    installable_deps,
+                    comment="Short alias for building this %s." % file_desc,
+                    phony=True,
+                )
+            if part_of_all:
+                self.WriteMakeRule(
+                    ["all"],
+                    [install_path],
+                    comment='Add %s to "all" target.' % file_desc,
+                    phony=True,
+                )
+
+    def WriteList(self, value_list, variable=None, prefix="", quoter=QuoteIfNecessary):
+        """Write a variable definition that is a list of values.
+
+        E.g. WriteList(['a','b'], 'foo', prefix='blah') writes out
+             foo = blaha blahb
+        but in a pretty-printed style.
+        """
+        values = ""
+        if value_list:
+            value_list = [quoter(prefix + value) for value in value_list]
+            values = " \\\n\t" + " \\\n\t".join(value_list)
+        self.fp.write(f"{variable} :={values}\n\n")
+
+    def WriteDoCmd(
+        self, outputs, inputs, command, part_of_all, comment=None, postbuilds=False
+    ):
+        """Write a Makefile rule that uses do_cmd.
+
+        This makes the outputs dependent on the command line that was run,
+        as well as support the V= make command line flag.
+        """
+        suffix = ""
+        if postbuilds:
+            assert "," not in command
+            suffix = ",,1"  # Tell do_cmd to honor $POSTBUILDS
+        self.WriteMakeRule(
+            outputs,
+            inputs,
+            actions=[f"$(call do_cmd,{command}{suffix})"],
+            comment=comment,
+            command=command,
+            force=True,
+        )
+        # Add our outputs to the list of targets we read depfiles from.
+        # all_deps is only used for deps file reading, and for deps files we replace
+        # spaces with ? because escaping doesn't work with make's $(sort) and
+        # other functions.
+        outputs = [QuoteSpaces(o, SPACE_REPLACEMENT) for o in outputs]
+        self.WriteLn("all_deps += %s" % " ".join(outputs))
+
+    def WriteMakeRule(
+        self,
+        outputs,
+        inputs,
+        actions=None,
+        comment=None,
+        order_only=False,
+        force=False,
+        phony=False,
+        command=None,
+    ):
+        """Write a Makefile rule, with some extra tricks.
+
+        outputs: a list of outputs for the rule (note: this is not directly
+                 supported by make; see comments below)
+        inputs: a list of inputs for the rule
+        actions: a list of shell commands to run for the rule
+        comment: a comment to put in the Makefile above the rule (also useful
+                 for making this Python script's code self-documenting)
+        order_only: if true, makes the dependency order-only
+        force: if true, include FORCE_DO_CMD as an order-only dep
+        phony: if true, the rule does not actually generate the named output, the
+               output is just a name to run the rule
+        command: (optional) command name to generate unambiguous labels
+        """
+        outputs = [QuoteSpaces(o) for o in outputs]
+        inputs = [QuoteSpaces(i) for i in inputs]
+
+        if comment:
+            self.WriteLn("# " + comment)
+        if phony:
+            self.WriteLn(".PHONY: " + " ".join(outputs))
+        if actions:
+            self.WriteLn("%s: TOOLSET := $(TOOLSET)" % outputs[0])
+        force_append = " FORCE_DO_CMD" if force else ""
+
+        if order_only:
+            # Order only rule: Just write a simple rule.
+            # TODO(evanm): just make order_only a list of deps instead of this hack.
+            self.WriteLn(
+                "{}: | {}{}".format(" ".join(outputs), " ".join(inputs), force_append)
+            )
+        elif len(outputs) == 1:
+            # Regular rule, one output: Just write a simple rule.
+            self.WriteLn("{}: {}{}".format(outputs[0], " ".join(inputs), force_append))
+        else:
+            # Regular rule, more than one output: Multiple outputs are tricky in
+            # make. We will write three rules:
+            # - All outputs depend on an intermediate file.
+            # - Make .INTERMEDIATE depend on the intermediate.
+            # - The intermediate file depends on the inputs and executes the
+            #   actual command.
+            # - The intermediate recipe will 'touch' the intermediate file.
+            # - The multi-output rule will have an do-nothing recipe.
+
+            # Hash the target name to avoid generating overlong filenames.
+            cmddigest = hashlib.sha1(
+                (command or self.target).encode("utf-8")
+            ).hexdigest()
+            intermediate = "%s.intermediate" % cmddigest
+            self.WriteLn("{}: {}".format(" ".join(outputs), intermediate))
+            self.WriteLn("\t%s" % "@:")
+            self.WriteLn("{}: {}".format(".INTERMEDIATE", intermediate))
+            self.WriteLn(
+                "{}: {}{}".format(intermediate, " ".join(inputs), force_append)
+            )
+            actions.insert(0, "$(call do_cmd,touch)")
+
+        if actions:
+            for action in actions:
+                self.WriteLn("\t%s" % action)
+        self.WriteLn()
+
+    def WriteAndroidNdkModuleRule(self, module_name, all_sources, link_deps):
+        """Write a set of LOCAL_XXX definitions for Android NDK.
+
+        These variable definitions will be used by Android NDK but do nothing for
+        non-Android applications.
+
+        Arguments:
+          module_name: Android NDK module name, which must be unique among all
+              module names.
+          all_sources: A list of source files (will be filtered by Compilable).
+          link_deps: A list of link dependencies, which must be sorted in
+              the order from dependencies to dependents.
+        """
+        if self.type not in ("executable", "shared_library", "static_library"):
+            return
+
+        self.WriteLn("# Variable definitions for Android applications")
+        self.WriteLn("include $(CLEAR_VARS)")
+        self.WriteLn("LOCAL_MODULE := " + module_name)
+        self.WriteLn(
+            "LOCAL_CFLAGS := $(CFLAGS_$(BUILDTYPE)) "
+            "$(DEFS_$(BUILDTYPE)) "
+            # LOCAL_CFLAGS is applied to both of C and C++.  There is
+            # no way to specify $(CFLAGS_C_$(BUILDTYPE)) only for C
+            # sources.
+            "$(CFLAGS_C_$(BUILDTYPE)) "
+            # $(INCS_$(BUILDTYPE)) includes the prefix '-I' while
+            # LOCAL_C_INCLUDES does not expect it.  So put it in
+            # LOCAL_CFLAGS.
+            "$(INCS_$(BUILDTYPE))"
+        )
+        # LOCAL_CXXFLAGS is obsolete and LOCAL_CPPFLAGS is preferred.
+        self.WriteLn("LOCAL_CPPFLAGS := $(CFLAGS_CC_$(BUILDTYPE))")
+        self.WriteLn("LOCAL_C_INCLUDES :=")
+        self.WriteLn("LOCAL_LDLIBS := $(LDFLAGS_$(BUILDTYPE)) $(LIBS)")
+
+        # Detect the C++ extension.
+        cpp_ext = {".cc": 0, ".cpp": 0, ".cxx": 0}
+        default_cpp_ext = ".cpp"
+        for filename in all_sources:
+            ext = os.path.splitext(filename)[1]
+            if ext in cpp_ext:
+                cpp_ext[ext] += 1
+                if cpp_ext[ext] > cpp_ext[default_cpp_ext]:
+                    default_cpp_ext = ext
+        self.WriteLn("LOCAL_CPP_EXTENSION := " + default_cpp_ext)
+
+        self.WriteList(
+            list(map(self.Absolutify, filter(Compilable, all_sources))),
+            "LOCAL_SRC_FILES",
+        )
+
+        # Filter out those which do not match prefix and suffix and produce
+        # the resulting list without prefix and suffix.
+        def DepsToModules(deps, prefix, suffix):
+            modules = []
+            for filepath in deps:
+                filename = os.path.basename(filepath)
+                if filename.startswith(prefix) and filename.endswith(suffix):
+                    modules.append(filename[len(prefix) : -len(suffix)])
+            return modules
+
+        # Retrieve the default value of 'SHARED_LIB_SUFFIX'
+        params = {"flavor": "linux"}
+        default_variables = {}
+        CalculateVariables(default_variables, params)
+
+        self.WriteList(
+            DepsToModules(
+                link_deps,
+                generator_default_variables["SHARED_LIB_PREFIX"],
+                default_variables["SHARED_LIB_SUFFIX"],
+            ),
+            "LOCAL_SHARED_LIBRARIES",
+        )
+        self.WriteList(
+            DepsToModules(
+                link_deps,
+                generator_default_variables["STATIC_LIB_PREFIX"],
+                generator_default_variables["STATIC_LIB_SUFFIX"],
+            ),
+            "LOCAL_STATIC_LIBRARIES",
+        )
+
+        if self.type == "executable":
+            self.WriteLn("include $(BUILD_EXECUTABLE)")
+        elif self.type == "shared_library":
+            self.WriteLn("include $(BUILD_SHARED_LIBRARY)")
+        elif self.type == "static_library":
+            self.WriteLn("include $(BUILD_STATIC_LIBRARY)")
+        self.WriteLn()
+
+    def WriteLn(self, text=""):
+        self.fp.write(text + "\n")
+
+    def GetSortedXcodeEnv(self, additional_settings=None):
+        return gyp.xcode_emulation.GetSortedXcodeEnv(
+            self.xcode_settings,
+            "$(abs_builddir)",
+            os.path.join("$(abs_srcdir)", self.path),
+            "$(BUILDTYPE)",
+            additional_settings,
+        )
+
+    def GetSortedXcodePostbuildEnv(self):
+        # CHROMIUM_STRIP_SAVE_FILE is a chromium-specific hack.
+        # TODO(thakis): It would be nice to have some general mechanism instead.
+        strip_save_file = self.xcode_settings.GetPerTargetSetting(
+            "CHROMIUM_STRIP_SAVE_FILE", ""
+        )
+        # Even if strip_save_file is empty, explicitly write it. Else a postbuild
+        # might pick up an export from an earlier target.
+        return self.GetSortedXcodeEnv(
+            additional_settings={"CHROMIUM_STRIP_SAVE_FILE": strip_save_file}
+        )
+
+    def WriteSortedXcodeEnv(self, target, env):
+        for k, v in env:
+            # For
+            #  foo := a\ b
+            # the escaped space does the right thing. For
+            #  export foo := a\ b
+            # it does not -- the backslash is written to the env as literal character.
+            # So don't escape spaces in |env[k]|.
+            self.WriteLn(f"{QuoteSpaces(target)}: export {k} := {v}")
+
+    def Objectify(self, path):
+        """Convert a path to its output directory form."""
+        if "$(" in path:
+            path = path.replace("$(obj)/", "$(obj).%s/$(TARGET)/" % self.toolset)
+        if "$(obj)" not in path:
+            path = f"$(obj).{self.toolset}/$(TARGET)/{path}"
+        return path
+
+    def Pchify(self, path, lang):
+        """Convert a prefix header path to its output directory form."""
+        path = self.Absolutify(path)
+        if "$(" in path:
+            path = path.replace(
+                "$(obj)/", f"$(obj).{self.toolset}/$(TARGET)/pch-{lang}"
+            )
+            return path
+        return f"$(obj).{self.toolset}/$(TARGET)/pch-{lang}/{path}"
+
+    def Absolutify(self, path):
+        """Convert a subdirectory-relative path into a base-relative path.
+        Skips over paths that contain variables."""
+        if "$(" in path:
+            # Don't call normpath in this case, as it might collapse the
+            # path too aggressively if it features '..'. However it's still
+            # important to strip trailing slashes.
+            return path.rstrip("/")
+        return os.path.normpath(os.path.join(self.path, path))
+
+    def ExpandInputRoot(self, template, expansion, dirname):
+        if "%(INPUT_ROOT)s" not in template and "%(INPUT_DIRNAME)s" not in template:
+            return template
+        path = template % {
+            "INPUT_ROOT": expansion,
+            "INPUT_DIRNAME": dirname,
+        }
+        return path
+
+    def _InstallableTargetInstallPath(self):
+        """Returns the location of the final output for an installable target."""
+        # Functionality removed for all platforms to match Xcode and hoist
+        # shared libraries into PRODUCT_DIR for users:
+        # Xcode puts shared_library results into PRODUCT_DIR, and some gyp files
+        # rely on this. Emulate this behavior for mac.
+        # if self.type == "shared_library" and (
+        #     self.flavor != "mac" or self.toolset != "target"
+        # ):
+        #    # Install all shared libs into a common directory (per toolset) for
+        #    # convenient access with LD_LIBRARY_PATH.
+        #    return "$(builddir)/lib.%s/%s" % (self.toolset, self.alias)
+        return "$(builddir)/" + self.alias
+
+
+def WriteAutoRegenerationRule(params, root_makefile, makefile_name, build_files):
+    """Write the target to regenerate the Makefile."""
+    options = params["options"]
+    build_files_args = [
+        gyp.common.RelativePath(filename, options.toplevel_dir)
+        for filename in params["build_files_arg"]
+    ]
+
+    gyp_binary = gyp.common.FixIfRelativePath(
+        params["gyp_binary"], options.toplevel_dir
+    )
+    if not gyp_binary.startswith(os.sep):
+        gyp_binary = os.path.join(".", gyp_binary)
+
+    root_makefile.write(
+        "quiet_cmd_regen_makefile = ACTION Regenerating $@\n"
+        "cmd_regen_makefile = cd $(srcdir); %(cmd)s\n"
+        "%(makefile_name)s: %(deps)s\n"
+        "\t$(call do_cmd,regen_makefile)\n\n"
+        % {
+            "makefile_name": makefile_name,
+            "deps": " ".join(SourceifyAndQuoteSpaces(bf) for bf in build_files),
+            "cmd": gyp.common.EncodePOSIXShellList(
+                [gyp_binary, "-fmake"] + gyp.RegenerateFlags(options) + build_files_args
+            ),
+        }
+    )
+
+
+def PerformBuild(data, configurations, params):
+    options = params["options"]
+    for config in configurations:
+        arguments = ["make"]
+        if options.toplevel_dir and options.toplevel_dir != ".":
+            arguments += "-C", options.toplevel_dir
+        arguments.append("BUILDTYPE=" + config)
+        print(f"Building [{config}]: {arguments}")
+        subprocess.check_call(arguments)
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    options = params["options"]
+    flavor = gyp.common.GetFlavor(params)
+    generator_flags = params.get("generator_flags", {})
+    builddir_name = generator_flags.get("output_dir", "out")
+    android_ndk_version = generator_flags.get("android_ndk_version", None)
+    default_target = generator_flags.get("default_target", "all")
+
+    def CalculateMakefilePath(build_file, base_name):
+        """Determine where to write a Makefile for a given gyp file."""
+        # Paths in gyp files are relative to the .gyp file, but we want
+        # paths relative to the source root for the master makefile.  Grab
+        # the path of the .gyp file as the base to relativize against.
+        # E.g. "foo/bar" when we're constructing targets for "foo/bar/baz.gyp".
+        base_path = gyp.common.RelativePath(os.path.dirname(build_file), options.depth)
+        # We write the file in the base_path directory.
+        output_file = os.path.join(options.depth, base_path, base_name)
+        if options.generator_output:
+            output_file = os.path.join(
+                options.depth, options.generator_output, base_path, base_name
+            )
+        base_path = gyp.common.RelativePath(
+            os.path.dirname(build_file), options.toplevel_dir
+        )
+        return base_path, output_file
+
+    # TODO:  search for the first non-'Default' target.  This can go
+    # away when we add verification that all targets have the
+    # necessary configurations.
+    default_configuration = None
+    toolsets = {target_dicts[target]["toolset"] for target in target_list}
+    for target in target_list:
+        spec = target_dicts[target]
+        if spec["default_configuration"] != "Default":
+            default_configuration = spec["default_configuration"]
+            break
+    if not default_configuration:
+        default_configuration = "Default"
+
+    srcdir = "."
+    makefile_name = "Makefile" + options.suffix
+    makefile_path = os.path.join(options.toplevel_dir, makefile_name)
+    if options.generator_output:
+        global srcdir_prefix
+        makefile_path = os.path.join(
+            options.toplevel_dir, options.generator_output, makefile_name
+        )
+        srcdir = gyp.common.RelativePath(srcdir, options.generator_output)
+        srcdir_prefix = "$(srcdir)/"
+
+    flock_command = "flock"
+    copy_archive_arguments = "-af"
+    makedep_arguments = "-MMD"
+    header_params = {
+        "default_target": default_target,
+        "builddir": builddir_name,
+        "default_configuration": default_configuration,
+        "flock": flock_command,
+        "flock_index": 1,
+        "link_commands": LINK_COMMANDS_LINUX,
+        "extra_commands": "",
+        "srcdir": srcdir,
+        "copy_archive_args": copy_archive_arguments,
+        "makedep_args": makedep_arguments,
+        "CC.target": GetEnvironFallback(("CC_target", "CC"), "$(CC)"),
+        "AR.target": GetEnvironFallback(("AR_target", "AR"), "$(AR)"),
+        "CXX.target": GetEnvironFallback(("CXX_target", "CXX"), "$(CXX)"),
+        "LINK.target": GetEnvironFallback(("LINK_target", "LINK"), "$(LINK)"),
+        "CC.host": GetEnvironFallback(("CC_host", "CC"), "gcc"),
+        "AR.host": GetEnvironFallback(("AR_host", "AR"), "ar"),
+        "CXX.host": GetEnvironFallback(("CXX_host", "CXX"), "g++"),
+        "LINK.host": GetEnvironFallback(("LINK_host", "LINK"), "$(CXX.host)"),
+    }
+    if flavor == "mac":
+        flock_command = "./gyp-mac-tool flock"
+        header_params.update(
+            {
+                "flock": flock_command,
+                "flock_index": 2,
+                "link_commands": LINK_COMMANDS_MAC,
+                "extra_commands": SHARED_HEADER_MAC_COMMANDS,
+            }
+        )
+    elif flavor == "android":
+        header_params.update({"link_commands": LINK_COMMANDS_ANDROID})
+    elif flavor == "zos":
+        copy_archive_arguments = "-fPR"
+        makedep_arguments = "-qmakedep=gcc"
+        header_params.update(
+            {
+                "copy_archive_args": copy_archive_arguments,
+                "makedep_args": makedep_arguments,
+                "link_commands": LINK_COMMANDS_OS390,
+                "CC.target": GetEnvironFallback(("CC_target", "CC"), "njsc"),
+                "CXX.target": GetEnvironFallback(("CXX_target", "CXX"), "njsc++"),
+                "CC.host": GetEnvironFallback(("CC_host", "CC"), "njsc"),
+                "CXX.host": GetEnvironFallback(("CXX_host", "CXX"), "njsc++"),
+            }
+        )
+    elif flavor == "solaris":
+        copy_archive_arguments = "-pPRf@"
+        header_params.update(
+            {
+                "copy_archive_args": copy_archive_arguments,
+                "flock": "./gyp-flock-tool flock",
+                "flock_index": 2,
+            }
+        )
+    elif flavor == "freebsd":
+        # Note: OpenBSD has sysutils/flock. lockf seems to be FreeBSD specific.
+        header_params.update({"flock": "lockf"})
+    elif flavor == "openbsd":
+        copy_archive_arguments = "-pPRf"
+        header_params.update({"copy_archive_args": copy_archive_arguments})
+    elif flavor == "aix":
+        copy_archive_arguments = "-pPRf"
+        header_params.update(
+            {
+                "copy_archive_args": copy_archive_arguments,
+                "link_commands": LINK_COMMANDS_AIX,
+                "flock": "./gyp-flock-tool flock",
+                "flock_index": 2,
+            }
+        )
+
+    build_file, _, _ = gyp.common.ParseQualifiedTarget(target_list[0])
+    make_global_settings_array = data[build_file].get("make_global_settings", [])
+    wrappers = {}
+    for key, value in make_global_settings_array:
+        if key.endswith("_wrapper"):
+            wrappers[key[: -len("_wrapper")]] = "$(abspath %s)" % value
+    make_global_settings = ""
+    for key, value in make_global_settings_array:
+        if re.match(".*_wrapper", key):
+            continue
+        if value[0] != "$":
+            value = "$(abspath %s)" % value
+        wrapper = wrappers.get(key)
+        if wrapper:
+            value = f"{wrapper} {value}"
+            del wrappers[key]
+        if key in ("CC", "CC.host", "CXX", "CXX.host"):
+            make_global_settings += (
+                "ifneq (,$(filter $(origin %s), undefined default))\n" % key
+            )
+            # Let gyp-time envvars win over global settings.
+            env_key = key.replace(".", "_")  # CC.host -> CC_host
+            if env_key in os.environ:
+                value = os.environ[env_key]
+            make_global_settings += f"  {key} = {value}\n"
+            make_global_settings += "endif\n"
+        else:
+            make_global_settings += f"{key} ?= {value}\n"
+    # TODO(ukai): define cmd when only wrapper is specified in
+    # make_global_settings.
+
+    header_params["make_global_settings"] = make_global_settings
+
+    gyp.common.EnsureDirExists(makefile_path)
+    root_makefile = open(makefile_path, "w")
+    root_makefile.write(SHARED_HEADER % header_params)
+    # Currently any versions have the same effect, but in future the behavior
+    # could be different.
+    if android_ndk_version:
+        root_makefile.write(
+            "# Define LOCAL_PATH for build of Android applications.\n"
+            "LOCAL_PATH := $(call my-dir)\n"
+            "\n"
+        )
+    for toolset in toolsets:
+        root_makefile.write("TOOLSET := %s\n" % toolset)
+        WriteRootHeaderSuffixRules(root_makefile)
+
+    # Put build-time support tools next to the root Makefile.
+    dest_path = os.path.dirname(makefile_path)
+    gyp.common.CopyTool(flavor, dest_path)
+
+    # Find the list of targets that derive from the gyp file(s) being built.
+    needed_targets = set()
+    for build_file in params["build_files"]:
+        for target in gyp.common.AllTargets(target_list, target_dicts, build_file):
+            needed_targets.add(target)
+
+    build_files = set()
+    include_list = set()
+    for qualified_target in target_list:
+        build_file, target, toolset = gyp.common.ParseQualifiedTarget(qualified_target)
+
+        this_make_global_settings = data[build_file].get("make_global_settings", [])
+        assert make_global_settings_array == this_make_global_settings, (
+            "make_global_settings needs to be the same for all targets "
+            f"{this_make_global_settings} vs. {make_global_settings}"
+        )
+
+        build_files.add(gyp.common.RelativePath(build_file, options.toplevel_dir))
+        included_files = data[build_file]["included_files"]
+        for included_file in included_files:
+            # The included_files entries are relative to the dir of the build file
+            # that included them, so we have to undo that and then make them relative
+            # to the root dir.
+            relative_include_file = gyp.common.RelativePath(
+                gyp.common.UnrelativePath(included_file, build_file),
+                options.toplevel_dir,
+            )
+            abs_include_file = os.path.abspath(relative_include_file)
+            # If the include file is from the ~/.gyp dir, we should use absolute path
+            # so that relocating the src dir doesn't break the path.
+            if params["home_dot_gyp"] and abs_include_file.startswith(
+                params["home_dot_gyp"]
+            ):
+                build_files.add(abs_include_file)
+            else:
+                build_files.add(relative_include_file)
+
+        base_path, output_file = CalculateMakefilePath(
+            build_file, target + "." + toolset + options.suffix + ".mk"
+        )
+
+        spec = target_dicts[qualified_target]
+        configs = spec["configurations"]
+
+        if flavor == "mac":
+            gyp.xcode_emulation.MergeGlobalXcodeSettingsToSpec(data[build_file], spec)
+
+        writer = MakefileWriter(generator_flags, flavor)
+        writer.Write(
+            qualified_target,
+            base_path,
+            output_file,
+            spec,
+            configs,
+            part_of_all=qualified_target in needed_targets,
+        )
+
+        # Our root_makefile lives at the source root.  Compute the relative path
+        # from there to the output_file for including.
+        mkfile_rel_path = gyp.common.RelativePath(
+            output_file, os.path.dirname(makefile_path)
+        )
+        include_list.add(mkfile_rel_path)
+
+    # Write out per-gyp (sub-project) Makefiles.
+    depth_rel_path = gyp.common.RelativePath(options.depth, os.getcwd())
+    for build_file in build_files:
+        # The paths in build_files were relativized above, so undo that before
+        # testing against the non-relativized items in target_list and before
+        # calculating the Makefile path.
+        build_file = os.path.join(depth_rel_path, build_file)
+        gyp_targets = [
+            target_dicts[qualified_target]["target_name"]
+            for qualified_target in target_list
+            if qualified_target.startswith(build_file)
+            and qualified_target in needed_targets
+        ]
+        # Only generate Makefiles for gyp files with targets.
+        if not gyp_targets:
+            continue
+        base_path, output_file = CalculateMakefilePath(
+            build_file, os.path.splitext(os.path.basename(build_file))[0] + ".Makefile"
+        )
+        makefile_rel_path = gyp.common.RelativePath(
+            os.path.dirname(makefile_path), os.path.dirname(output_file)
+        )
+        writer.WriteSubMake(output_file, makefile_rel_path, gyp_targets, builddir_name)
+
+    # Write out the sorted list of includes.
+    root_makefile.write("\n")
+    for include_file in sorted(include_list):
+        # We wrap each .mk include in an if statement so users can tell make to
+        # not load a file by setting NO_LOAD.  The below make code says, only
+        # load the .mk file if the .mk filename doesn't start with a token in
+        # NO_LOAD.
+        root_makefile.write(
+            "ifeq ($(strip $(foreach prefix,$(NO_LOAD),\\\n"
+            "    $(findstring $(join ^,$(prefix)),\\\n"
+            "                 $(join ^," + include_file + ")))),)\n"
+        )
+        root_makefile.write("  include " + include_file + "\n")
+        root_makefile.write("endif\n")
+    root_makefile.write("\n")
+
+    if not generator_flags.get("standalone") and generator_flags.get(
+        "auto_regeneration", True
+    ):
+        WriteAutoRegenerationRule(params, root_makefile, makefile_name, build_files)
+
+    root_makefile.write(SHARED_FOOTER)
+
+    root_makefile.close()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/msvs.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/msvs.py
new file mode 100644
index 0000000..8308fa8
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/msvs.py
@@ -0,0 +1,3978 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+import ntpath
+import os
+import posixpath
+import re
+import subprocess
+import sys
+
+from collections import OrderedDict
+
+import gyp.common
+import gyp.easy_xml as easy_xml
+import gyp.generator.ninja as ninja_generator
+import gyp.MSVSNew as MSVSNew
+import gyp.MSVSProject as MSVSProject
+import gyp.MSVSSettings as MSVSSettings
+import gyp.MSVSToolFile as MSVSToolFile
+import gyp.MSVSUserFile as MSVSUserFile
+import gyp.MSVSUtil as MSVSUtil
+import gyp.MSVSVersion as MSVSVersion
+from gyp.common import GypError
+from gyp.common import OrderedSet
+
+
+# Regular expression for validating Visual Studio GUIDs.  If the GUID
+# contains lowercase hex letters, MSVS will be fine. However,
+# IncrediBuild BuildConsole will parse the solution file, but then
+# silently skip building the target causing hard to track down errors.
+# Note that this only happens with the BuildConsole, and does not occur
+# if IncrediBuild is executed from inside Visual Studio.  This regex
+# validates that the string looks like a GUID with all uppercase hex
+# letters.
+VALID_MSVS_GUID_CHARS = re.compile(r"^[A-F0-9\-]+$")
+
+generator_supports_multiple_toolsets = gyp.common.CrossCompileRequested()
+
+generator_default_variables = {
+    "DRIVER_PREFIX": "",
+    "DRIVER_SUFFIX": ".sys",
+    "EXECUTABLE_PREFIX": "",
+    "EXECUTABLE_SUFFIX": ".exe",
+    "STATIC_LIB_PREFIX": "",
+    "SHARED_LIB_PREFIX": "",
+    "STATIC_LIB_SUFFIX": ".lib",
+    "SHARED_LIB_SUFFIX": ".dll",
+    "INTERMEDIATE_DIR": "$(IntDir)",
+    "SHARED_INTERMEDIATE_DIR": "$(OutDir)/obj/global_intermediate",
+    "OS": "win",
+    "PRODUCT_DIR": "$(OutDir)",
+    "LIB_DIR": "$(OutDir)lib",
+    "RULE_INPUT_ROOT": "$(InputName)",
+    "RULE_INPUT_DIRNAME": "$(InputDir)",
+    "RULE_INPUT_EXT": "$(InputExt)",
+    "RULE_INPUT_NAME": "$(InputFileName)",
+    "RULE_INPUT_PATH": "$(InputPath)",
+    "CONFIGURATION_NAME": "$(ConfigurationName)",
+}
+
+
+# The msvs specific sections that hold paths
+generator_additional_path_sections = [
+    "msvs_cygwin_dirs",
+    "msvs_props",
+]
+
+
+generator_additional_non_configuration_keys = [
+    "msvs_cygwin_dirs",
+    "msvs_cygwin_shell",
+    "msvs_large_pdb",
+    "msvs_shard",
+    "msvs_external_builder",
+    "msvs_external_builder_out_dir",
+    "msvs_external_builder_build_cmd",
+    "msvs_external_builder_clean_cmd",
+    "msvs_external_builder_clcompile_cmd",
+    "msvs_enable_winrt",
+    "msvs_requires_importlibrary",
+    "msvs_enable_winphone",
+    "msvs_application_type_revision",
+    "msvs_target_platform_version",
+    "msvs_target_platform_minversion",
+]
+
+generator_filelist_paths = None
+
+# List of precompiled header related keys.
+precomp_keys = [
+    "msvs_precompiled_header",
+    "msvs_precompiled_source",
+]
+
+
+cached_username = None
+
+
+cached_domain = None
+
+
+# TODO(gspencer): Switch the os.environ calls to be
+# win32api.GetDomainName() and win32api.GetUserName() once the
+# python version in depot_tools has been updated to work on Vista
+# 64-bit.
+def _GetDomainAndUserName():
+    if sys.platform not in ("win32", "cygwin"):
+        return ("DOMAIN", "USERNAME")
+    global cached_username
+    global cached_domain
+    if not cached_domain or not cached_username:
+        domain = os.environ.get("USERDOMAIN")
+        username = os.environ.get("USERNAME")
+        if not domain or not username:
+            call = subprocess.Popen(
+                ["net", "config", "Workstation"], stdout=subprocess.PIPE
+            )
+            config = call.communicate()[0].decode("utf-8")
+            username_re = re.compile(r"^User name\s+(\S+)", re.MULTILINE)
+            username_match = username_re.search(config)
+            if username_match:
+                username = username_match.group(1)
+            domain_re = re.compile(r"^Logon domain\s+(\S+)", re.MULTILINE)
+            domain_match = domain_re.search(config)
+            if domain_match:
+                domain = domain_match.group(1)
+        cached_domain = domain
+        cached_username = username
+    return (cached_domain, cached_username)
+
+
+fixpath_prefix = None
+
+
+def _NormalizedSource(source):
+    """Normalize the path.
+
+  But not if that gets rid of a variable, as this may expand to something
+  larger than one directory.
+
+  Arguments:
+      source: The path to be normalize.d
+
+  Returns:
+      The normalized path.
+  """
+    normalized = os.path.normpath(source)
+    if source.count("$") == normalized.count("$"):
+        source = normalized
+    return source
+
+
+def _FixPath(path, separator="\\"):
+    """Convert paths to a form that will make sense in a vcproj file.
+
+  Arguments:
+    path: The path to convert, may contain / etc.
+  Returns:
+    The path with all slashes made into backslashes.
+  """
+    if (
+        fixpath_prefix
+        and path
+        and not os.path.isabs(path)
+        and not path[0] == "$"
+        and not _IsWindowsAbsPath(path)
+    ):
+        path = os.path.join(fixpath_prefix, path)
+    if separator == "\\":
+        path = path.replace("/", "\\")
+    path = _NormalizedSource(path)
+    if separator == "/":
+        path = path.replace("\\", "/")
+    if path and path[-1] == separator:
+        path = path[:-1]
+    return path
+
+
+def _IsWindowsAbsPath(path):
+    """
+  On Cygwin systems Python needs a little help determining if a path
+  is an absolute Windows path or not, so that
+  it does not treat those as relative, which results in bad paths like:
+  '..\\C:\\<some path>\\some_source_code_file.cc'
+  """
+    return path.startswith("c:") or path.startswith("C:")
+
+
+def _FixPaths(paths, separator="\\"):
+    """Fix each of the paths of the list."""
+    return [_FixPath(i, separator) for i in paths]
+
+
+def _ConvertSourcesToFilterHierarchy(
+    sources, prefix=None, excluded=None, list_excluded=True, msvs_version=None
+):
+    """Converts a list split source file paths into a vcproj folder hierarchy.
+
+  Arguments:
+    sources: A list of source file paths split.
+    prefix: A list of source file path layers meant to apply to each of sources.
+    excluded: A set of excluded files.
+    msvs_version: A MSVSVersion object.
+
+  Returns:
+    A hierarchy of filenames and MSVSProject.Filter objects that matches the
+    layout of the source tree.
+    For example:
+    _ConvertSourcesToFilterHierarchy([['a', 'bob1.c'], ['b', 'bob2.c']],
+                                     prefix=['joe'])
+    -->
+    [MSVSProject.Filter('a', contents=['joe\\a\\bob1.c']),
+     MSVSProject.Filter('b', contents=['joe\\b\\bob2.c'])]
+  """
+    if not prefix:
+        prefix = []
+    result = []
+    excluded_result = []
+    folders = OrderedDict()
+    # Gather files into the final result, excluded, or folders.
+    for s in sources:
+        if len(s) == 1:
+            filename = _NormalizedSource("\\".join(prefix + s))
+            if filename in excluded:
+                excluded_result.append(filename)
+            else:
+                result.append(filename)
+        elif msvs_version and not msvs_version.UsesVcxproj():
+            # For MSVS 2008 and earlier, we need to process all files before walking
+            # the sub folders.
+            if not folders.get(s[0]):
+                folders[s[0]] = []
+            folders[s[0]].append(s[1:])
+        else:
+            contents = _ConvertSourcesToFilterHierarchy(
+                [s[1:]],
+                prefix + [s[0]],
+                excluded=excluded,
+                list_excluded=list_excluded,
+                msvs_version=msvs_version,
+            )
+            contents = MSVSProject.Filter(s[0], contents=contents)
+            result.append(contents)
+    # Add a folder for excluded files.
+    if excluded_result and list_excluded:
+        excluded_folder = MSVSProject.Filter(
+            "_excluded_files", contents=excluded_result
+        )
+        result.append(excluded_folder)
+
+    if msvs_version and msvs_version.UsesVcxproj():
+        return result
+
+    # Populate all the folders.
+    for f in folders:
+        contents = _ConvertSourcesToFilterHierarchy(
+            folders[f],
+            prefix=prefix + [f],
+            excluded=excluded,
+            list_excluded=list_excluded,
+            msvs_version=msvs_version,
+        )
+        contents = MSVSProject.Filter(f, contents=contents)
+        result.append(contents)
+    return result
+
+
+def _ToolAppend(tools, tool_name, setting, value, only_if_unset=False):
+    if not value:
+        return
+    _ToolSetOrAppend(tools, tool_name, setting, value, only_if_unset)
+
+
+def _ToolSetOrAppend(tools, tool_name, setting, value, only_if_unset=False):
+    # TODO(bradnelson): ugly hack, fix this more generally!!!
+    if "Directories" in setting or "Dependencies" in setting:
+        if type(value) == str:
+            value = value.replace("/", "\\")
+        else:
+            value = [i.replace("/", "\\") for i in value]
+    if not tools.get(tool_name):
+        tools[tool_name] = dict()
+    tool = tools[tool_name]
+    if "CompileAsWinRT" == setting:
+        return
+    if tool.get(setting):
+        if only_if_unset:
+            return
+        if type(tool[setting]) == list and type(value) == list:
+            tool[setting] += value
+        else:
+            raise TypeError(
+                'Appending "%s" to a non-list setting "%s" for tool "%s" is '
+                "not allowed, previous value: %s"
+                % (value, setting, tool_name, str(tool[setting]))
+            )
+    else:
+        tool[setting] = value
+
+
+def _ConfigTargetVersion(config_data):
+    return config_data.get("msvs_target_version", "Windows7")
+
+
+def _ConfigPlatform(config_data):
+    return config_data.get("msvs_configuration_platform", "Win32")
+
+
+def _ConfigBaseName(config_name, platform_name):
+    if config_name.endswith("_" + platform_name):
+        return config_name[0 : -len(platform_name) - 1]
+    else:
+        return config_name
+
+
+def _ConfigFullName(config_name, config_data):
+    platform_name = _ConfigPlatform(config_data)
+    return f"{_ConfigBaseName(config_name, platform_name)}|{platform_name}"
+
+
+def _ConfigWindowsTargetPlatformVersion(config_data, version):
+    target_ver = config_data.get("msvs_windows_target_platform_version")
+    if target_ver and re.match(r"^\d+", target_ver):
+        return target_ver
+    config_ver = config_data.get("msvs_windows_sdk_version")
+    vers = [config_ver] if config_ver else version.compatible_sdks
+    for ver in vers:
+        for key in [
+            r"HKLM\Software\Microsoft\Microsoft SDKs\Windows\%s",
+            r"HKLM\Software\Wow6432Node\Microsoft\Microsoft SDKs\Windows\%s",
+        ]:
+            sdk_dir = MSVSVersion._RegistryGetValue(key % ver, "InstallationFolder")
+            if not sdk_dir:
+                continue
+            version = MSVSVersion._RegistryGetValue(key % ver, "ProductVersion") or ""
+            # Find a matching entry in sdk_dir\include.
+            expected_sdk_dir = r"%s\include" % sdk_dir
+            names = sorted(
+                (
+                    x
+                    for x in (
+                        os.listdir(expected_sdk_dir)
+                        if os.path.isdir(expected_sdk_dir)
+                        else []
+                    )
+                    if x.startswith(version)
+                ),
+                reverse=True,
+            )
+            if names:
+                return names[0]
+            else:
+                print(
+                    "Warning: No include files found for detected "
+                    "Windows SDK version %s" % (version),
+                    file=sys.stdout,
+                )
+
+
+def _BuildCommandLineForRuleRaw(
+    spec, cmd, cygwin_shell, has_input_path, quote_cmd, do_setup_env
+):
+
+    if [x for x in cmd if "$(InputDir)" in x]:
+        input_dir_preamble = (
+            "set INPUTDIR=$(InputDir)\n"
+            "if NOT DEFINED INPUTDIR set INPUTDIR=.\\\n"
+            "set INPUTDIR=%INPUTDIR:~0,-1%\n"
+        )
+    else:
+        input_dir_preamble = ""
+
+    if cygwin_shell:
+        # Find path to cygwin.
+        cygwin_dir = _FixPath(spec.get("msvs_cygwin_dirs", ["."])[0])
+        # Prepare command.
+        direct_cmd = cmd
+        direct_cmd = [
+            i.replace("$(IntDir)", '`cygpath -m "${INTDIR}"`') for i in direct_cmd
+        ]
+        direct_cmd = [
+            i.replace("$(OutDir)", '`cygpath -m "${OUTDIR}"`') for i in direct_cmd
+        ]
+        direct_cmd = [
+            i.replace("$(InputDir)", '`cygpath -m "${INPUTDIR}"`') for i in direct_cmd
+        ]
+        if has_input_path:
+            direct_cmd = [
+                i.replace("$(InputPath)", '`cygpath -m "${INPUTPATH}"`')
+                for i in direct_cmd
+            ]
+        direct_cmd = ['\\"%s\\"' % i.replace('"', '\\\\\\"') for i in direct_cmd]
+        # direct_cmd = gyp.common.EncodePOSIXShellList(direct_cmd)
+        direct_cmd = " ".join(direct_cmd)
+        # TODO(quote):  regularize quoting path names throughout the module
+        cmd = ""
+        if do_setup_env:
+            cmd += 'call "$(ProjectDir)%(cygwin_dir)s\\setup_env.bat" && '
+        cmd += "set CYGWIN=nontsec&& "
+        if direct_cmd.find("NUMBER_OF_PROCESSORS") >= 0:
+            cmd += "set /a NUMBER_OF_PROCESSORS_PLUS_1=%%NUMBER_OF_PROCESSORS%%+1&& "
+        if direct_cmd.find("INTDIR") >= 0:
+            cmd += "set INTDIR=$(IntDir)&& "
+        if direct_cmd.find("OUTDIR") >= 0:
+            cmd += "set OUTDIR=$(OutDir)&& "
+        if has_input_path and direct_cmd.find("INPUTPATH") >= 0:
+            cmd += "set INPUTPATH=$(InputPath) && "
+        cmd += 'bash -c "%(cmd)s"'
+        cmd = cmd % {"cygwin_dir": cygwin_dir, "cmd": direct_cmd}
+        return input_dir_preamble + cmd
+    else:
+        # Convert cat --> type to mimic unix.
+        if cmd[0] == "cat":
+            command = ["type"]
+        else:
+            command = [cmd[0].replace("/", "\\")]
+        # Add call before command to ensure that commands can be tied together one
+        # after the other without aborting in Incredibuild, since IB makes a bat
+        # file out of the raw command string, and some commands (like python) are
+        # actually batch files themselves.
+        command.insert(0, "call")
+        # Fix the paths
+        # TODO(quote): This is a really ugly heuristic, and will miss path fixing
+        #              for arguments like "--arg=path" or "/opt:path".
+        # If the argument starts with a slash or dash, it's probably a command line
+        # switch
+        # Return the path with forward slashes because the command using it might
+        # not support backslashes.
+        arguments = [i if (i[:1] in "/-") else _FixPath(i, "/") for i in cmd[1:]]
+        arguments = [i.replace("$(InputDir)", "%INPUTDIR%") for i in arguments]
+        arguments = [MSVSSettings.FixVCMacroSlashes(i) for i in arguments]
+        if quote_cmd:
+            # Support a mode for using cmd directly.
+            # Convert any paths to native form (first element is used directly).
+            # TODO(quote):  regularize quoting path names throughout the module
+            arguments = ['"%s"' % i for i in arguments]
+        # Collapse into a single command.
+        return input_dir_preamble + " ".join(command + arguments)
+
+
+def _BuildCommandLineForRule(spec, rule, has_input_path, do_setup_env):
+    # Currently this weird argument munging is used to duplicate the way a
+    # python script would need to be run as part of the chrome tree.
+    # Eventually we should add some sort of rule_default option to set this
+    # per project. For now the behavior chrome needs is the default.
+    mcs = rule.get("msvs_cygwin_shell")
+    if mcs is None:
+        mcs = int(spec.get("msvs_cygwin_shell", 1))
+    elif isinstance(mcs, str):
+        mcs = int(mcs)
+    quote_cmd = int(rule.get("msvs_quote_cmd", 1))
+    return _BuildCommandLineForRuleRaw(
+        spec, rule["action"], mcs, has_input_path, quote_cmd, do_setup_env=do_setup_env
+    )
+
+
+def _AddActionStep(actions_dict, inputs, outputs, description, command):
+    """Merge action into an existing list of actions.
+
+  Care must be taken so that actions which have overlapping inputs either don't
+  get assigned to the same input, or get collapsed into one.
+
+  Arguments:
+    actions_dict: dictionary keyed on input name, which maps to a list of
+      dicts describing the actions attached to that input file.
+    inputs: list of inputs
+    outputs: list of outputs
+    description: description of the action
+    command: command line to execute
+  """
+    # Require there to be at least one input (call sites will ensure this).
+    assert inputs
+
+    action = {
+        "inputs": inputs,
+        "outputs": outputs,
+        "description": description,
+        "command": command,
+    }
+
+    # Pick where to stick this action.
+    # While less than optimal in terms of build time, attach them to the first
+    # input for now.
+    chosen_input = inputs[0]
+
+    # Add it there.
+    if chosen_input not in actions_dict:
+        actions_dict[chosen_input] = []
+    actions_dict[chosen_input].append(action)
+
+
+def _AddCustomBuildToolForMSVS(
+    p, spec, primary_input, inputs, outputs, description, cmd
+):
+    """Add a custom build tool to execute something.
+
+  Arguments:
+    p: the target project
+    spec: the target project dict
+    primary_input: input file to attach the build tool to
+    inputs: list of inputs
+    outputs: list of outputs
+    description: description of the action
+    cmd: command line to execute
+  """
+    inputs = _FixPaths(inputs)
+    outputs = _FixPaths(outputs)
+    tool = MSVSProject.Tool(
+        "VCCustomBuildTool",
+        {
+            "Description": description,
+            "AdditionalDependencies": ";".join(inputs),
+            "Outputs": ";".join(outputs),
+            "CommandLine": cmd,
+        },
+    )
+    # Add to the properties of primary input for each config.
+    for config_name, c_data in spec["configurations"].items():
+        p.AddFileConfig(
+            _FixPath(primary_input), _ConfigFullName(config_name, c_data), tools=[tool]
+        )
+
+
+def _AddAccumulatedActionsToMSVS(p, spec, actions_dict):
+    """Add actions accumulated into an actions_dict, merging as needed.
+
+  Arguments:
+    p: the target project
+    spec: the target project dict
+    actions_dict: dictionary keyed on input name, which maps to a list of
+        dicts describing the actions attached to that input file.
+  """
+    for primary_input in actions_dict:
+        inputs = OrderedSet()
+        outputs = OrderedSet()
+        descriptions = []
+        commands = []
+        for action in actions_dict[primary_input]:
+            inputs.update(OrderedSet(action["inputs"]))
+            outputs.update(OrderedSet(action["outputs"]))
+            descriptions.append(action["description"])
+            commands.append(action["command"])
+        # Add the custom build step for one input file.
+        description = ", and also ".join(descriptions)
+        command = "\r\n".join(commands)
+        _AddCustomBuildToolForMSVS(
+            p,
+            spec,
+            primary_input=primary_input,
+            inputs=inputs,
+            outputs=outputs,
+            description=description,
+            cmd=command,
+        )
+
+
+def _RuleExpandPath(path, input_file):
+    """Given the input file to which a rule applied, string substitute a path.
+
+  Arguments:
+    path: a path to string expand
+    input_file: the file to which the rule applied.
+  Returns:
+    The string substituted path.
+  """
+    path = path.replace(
+        "$(InputName)", os.path.splitext(os.path.split(input_file)[1])[0]
+    )
+    path = path.replace("$(InputDir)", os.path.dirname(input_file))
+    path = path.replace(
+        "$(InputExt)", os.path.splitext(os.path.split(input_file)[1])[1]
+    )
+    path = path.replace("$(InputFileName)", os.path.split(input_file)[1])
+    path = path.replace("$(InputPath)", input_file)
+    return path
+
+
+def _FindRuleTriggerFiles(rule, sources):
+    """Find the list of files which a particular rule applies to.
+
+  Arguments:
+    rule: the rule in question
+    sources: the set of all known source files for this project
+  Returns:
+    The list of sources that trigger a particular rule.
+  """
+    return rule.get("rule_sources", [])
+
+
+def _RuleInputsAndOutputs(rule, trigger_file):
+    """Find the inputs and outputs generated by a rule.
+
+  Arguments:
+    rule: the rule in question.
+    trigger_file: the main trigger for this rule.
+  Returns:
+    The pair of (inputs, outputs) involved in this rule.
+  """
+    raw_inputs = _FixPaths(rule.get("inputs", []))
+    raw_outputs = _FixPaths(rule.get("outputs", []))
+    inputs = OrderedSet()
+    outputs = OrderedSet()
+    inputs.add(trigger_file)
+    for i in raw_inputs:
+        inputs.add(_RuleExpandPath(i, trigger_file))
+    for o in raw_outputs:
+        outputs.add(_RuleExpandPath(o, trigger_file))
+    return (inputs, outputs)
+
+
+def _GenerateNativeRulesForMSVS(p, rules, output_dir, spec, options):
+    """Generate a native rules file.
+
+  Arguments:
+    p: the target project
+    rules: the set of rules to include
+    output_dir: the directory in which the project/gyp resides
+    spec: the project dict
+    options: global generator options
+  """
+    rules_filename = "{}{}.rules".format(spec["target_name"], options.suffix)
+    rules_file = MSVSToolFile.Writer(
+        os.path.join(output_dir, rules_filename), spec["target_name"]
+    )
+    # Add each rule.
+    for r in rules:
+        rule_name = r["rule_name"]
+        rule_ext = r["extension"]
+        inputs = _FixPaths(r.get("inputs", []))
+        outputs = _FixPaths(r.get("outputs", []))
+        # Skip a rule with no action and no inputs.
+        if "action" not in r and not r.get("rule_sources", []):
+            continue
+        cmd = _BuildCommandLineForRule(spec, r, has_input_path=True, do_setup_env=True)
+        rules_file.AddCustomBuildRule(
+            name=rule_name,
+            description=r.get("message", rule_name),
+            extensions=[rule_ext],
+            additional_dependencies=inputs,
+            outputs=outputs,
+            cmd=cmd,
+        )
+    # Write out rules file.
+    rules_file.WriteIfChanged()
+
+    # Add rules file to project.
+    p.AddToolFile(rules_filename)
+
+
+def _Cygwinify(path):
+    path = path.replace("$(OutDir)", "$(OutDirCygwin)")
+    path = path.replace("$(IntDir)", "$(IntDirCygwin)")
+    return path
+
+
+def _GenerateExternalRules(rules, output_dir, spec, sources, options, actions_to_add):
+    """Generate an external makefile to do a set of rules.
+
+  Arguments:
+    rules: the list of rules to include
+    output_dir: path containing project and gyp files
+    spec: project specification data
+    sources: set of sources known
+    options: global generator options
+    actions_to_add: The list of actions we will add to.
+  """
+    filename = "{}_rules{}.mk".format(spec["target_name"], options.suffix)
+    mk_file = gyp.common.WriteOnDiff(os.path.join(output_dir, filename))
+    # Find cygwin style versions of some paths.
+    mk_file.write('OutDirCygwin:=$(shell cygpath -u "$(OutDir)")\n')
+    mk_file.write('IntDirCygwin:=$(shell cygpath -u "$(IntDir)")\n')
+    # Gather stuff needed to emit all: target.
+    all_inputs = OrderedSet()
+    all_outputs = OrderedSet()
+    all_output_dirs = OrderedSet()
+    first_outputs = []
+    for rule in rules:
+        trigger_files = _FindRuleTriggerFiles(rule, sources)
+        for tf in trigger_files:
+            inputs, outputs = _RuleInputsAndOutputs(rule, tf)
+            all_inputs.update(OrderedSet(inputs))
+            all_outputs.update(OrderedSet(outputs))
+            # Only use one target from each rule as the dependency for
+            # 'all' so we don't try to build each rule multiple times.
+            first_outputs.append(list(outputs)[0])
+            # Get the unique output directories for this rule.
+            output_dirs = [os.path.split(i)[0] for i in outputs]
+            for od in output_dirs:
+                all_output_dirs.add(od)
+    first_outputs_cyg = [_Cygwinify(i) for i in first_outputs]
+    # Write out all: target, including mkdir for each output directory.
+    mk_file.write("all: %s\n" % " ".join(first_outputs_cyg))
+    for od in all_output_dirs:
+        if od:
+            mk_file.write('\tmkdir -p `cygpath -u "%s"`\n' % od)
+    mk_file.write("\n")
+    # Define how each output is generated.
+    for rule in rules:
+        trigger_files = _FindRuleTriggerFiles(rule, sources)
+        for tf in trigger_files:
+            # Get all the inputs and outputs for this rule for this trigger file.
+            inputs, outputs = _RuleInputsAndOutputs(rule, tf)
+            inputs = [_Cygwinify(i) for i in inputs]
+            outputs = [_Cygwinify(i) for i in outputs]
+            # Prepare the command line for this rule.
+            cmd = [_RuleExpandPath(c, tf) for c in rule["action"]]
+            cmd = ['"%s"' % i for i in cmd]
+            cmd = " ".join(cmd)
+            # Add it to the makefile.
+            mk_file.write("{}: {}\n".format(" ".join(outputs), " ".join(inputs)))
+            mk_file.write("\t%s\n\n" % cmd)
+    # Close up the file.
+    mk_file.close()
+
+    # Add makefile to list of sources.
+    sources.add(filename)
+    # Add a build action to call makefile.
+    cmd = [
+        "make",
+        "OutDir=$(OutDir)",
+        "IntDir=$(IntDir)",
+        "-j",
+        "${NUMBER_OF_PROCESSORS_PLUS_1}",
+        "-f",
+        filename,
+    ]
+    cmd = _BuildCommandLineForRuleRaw(spec, cmd, True, False, True, True)
+    # Insert makefile as 0'th input, so it gets the action attached there,
+    # as this is easier to understand from in the IDE.
+    all_inputs = list(all_inputs)
+    all_inputs.insert(0, filename)
+    _AddActionStep(
+        actions_to_add,
+        inputs=_FixPaths(all_inputs),
+        outputs=_FixPaths(all_outputs),
+        description="Running external rules for %s" % spec["target_name"],
+        command=cmd,
+    )
+
+
+def _EscapeEnvironmentVariableExpansion(s):
+    """Escapes % characters.
+
+  Escapes any % characters so that Windows-style environment variable
+  expansions will leave them alone.
+  See http://connect.microsoft.com/VisualStudio/feedback/details/106127/cl-d-name-text-containing-percentage-characters-doesnt-compile
+  to understand why we have to do this.
+
+  Args:
+      s: The string to be escaped.
+
+  Returns:
+      The escaped string.
+  """  # noqa: E731,E123,E501
+    s = s.replace("%", "%%")
+    return s
+
+
+quote_replacer_regex = re.compile(r'(\\*)"')
+
+
+def _EscapeCommandLineArgumentForMSVS(s):
+    """Escapes a Windows command-line argument.
+
+  So that the Win32 CommandLineToArgv function will turn the escaped result back
+  into the original string.
+  See http://msdn.microsoft.com/en-us/library/17w5ykft.aspx
+  ("Parsing C++ Command-Line Arguments") to understand why we have to do
+  this.
+
+  Args:
+      s: the string to be escaped.
+  Returns:
+      the escaped string.
+  """
+
+    def _Replace(match):
+        # For a literal quote, CommandLineToArgv requires an odd number of
+        # backslashes preceding it, and it produces half as many literal backslashes
+        # (rounded down). So we need to produce 2n+1 backslashes.
+        return 2 * match.group(1) + '\\"'
+
+    # Escape all quotes so that they are interpreted literally.
+    s = quote_replacer_regex.sub(_Replace, s)
+    # Now add unescaped quotes so that any whitespace is interpreted literally.
+    s = '"' + s + '"'
+    return s
+
+
+delimiters_replacer_regex = re.compile(r"(\\*)([,;]+)")
+
+
+def _EscapeVCProjCommandLineArgListItem(s):
+    """Escapes command line arguments for MSVS.
+
+  The VCProj format stores string lists in a single string using commas and
+  semi-colons as separators, which must be quoted if they are to be
+  interpreted literally. However, command-line arguments may already have
+  quotes, and the VCProj parser is ignorant of the backslash escaping
+  convention used by CommandLineToArgv, so the command-line quotes and the
+  VCProj quotes may not be the same quotes. So to store a general
+  command-line argument in a VCProj list, we need to parse the existing
+  quoting according to VCProj's convention and quote any delimiters that are
+  not already quoted by that convention. The quotes that we add will also be
+  seen by CommandLineToArgv, so if backslashes precede them then we also have
+  to escape those backslashes according to the CommandLineToArgv
+  convention.
+
+  Args:
+      s: the string to be escaped.
+  Returns:
+      the escaped string.
+  """
+
+    def _Replace(match):
+        # For a non-literal quote, CommandLineToArgv requires an even number of
+        # backslashes preceding it, and it produces half as many literal
+        # backslashes. So we need to produce 2n backslashes.
+        return 2 * match.group(1) + '"' + match.group(2) + '"'
+
+    segments = s.split('"')
+    # The unquoted segments are at the even-numbered indices.
+    for i in range(0, len(segments), 2):
+        segments[i] = delimiters_replacer_regex.sub(_Replace, segments[i])
+    # Concatenate back into a single string
+    s = '"'.join(segments)
+    if len(segments) % 2 == 0:
+        # String ends while still quoted according to VCProj's convention. This
+        # means the delimiter and the next list item that follow this one in the
+        # .vcproj file will be misinterpreted as part of this item. There is nothing
+        # we can do about this. Adding an extra quote would correct the problem in
+        # the VCProj but cause the same problem on the final command-line. Moving
+        # the item to the end of the list does works, but that's only possible if
+        # there's only one such item. Let's just warn the user.
+        print(
+            "Warning: MSVS may misinterpret the odd number of " + "quotes in " + s,
+            file=sys.stderr,
+        )
+    return s
+
+
+def _EscapeCppDefineForMSVS(s):
+    """Escapes a CPP define so that it will reach the compiler unaltered."""
+    s = _EscapeEnvironmentVariableExpansion(s)
+    s = _EscapeCommandLineArgumentForMSVS(s)
+    s = _EscapeVCProjCommandLineArgListItem(s)
+    # cl.exe replaces literal # characters with = in preprocessor definitions for
+    # some reason. Octal-encode to work around that.
+    s = s.replace("#", "\\%03o" % ord("#"))
+    return s
+
+
+quote_replacer_regex2 = re.compile(r'(\\+)"')
+
+
+def _EscapeCommandLineArgumentForMSBuild(s):
+    """Escapes a Windows command-line argument for use by MSBuild."""
+
+    def _Replace(match):
+        return (len(match.group(1)) / 2 * 4) * "\\" + '\\"'
+
+    # Escape all quotes so that they are interpreted literally.
+    s = quote_replacer_regex2.sub(_Replace, s)
+    return s
+
+
+def _EscapeMSBuildSpecialCharacters(s):
+    escape_dictionary = {
+        "%": "%25",
+        "$": "%24",
+        "@": "%40",
+        "'": "%27",
+        ";": "%3B",
+        "?": "%3F",
+        "*": "%2A",
+    }
+    result = "".join([escape_dictionary.get(c, c) for c in s])
+    return result
+
+
+def _EscapeCppDefineForMSBuild(s):
+    """Escapes a CPP define so that it will reach the compiler unaltered."""
+    s = _EscapeEnvironmentVariableExpansion(s)
+    s = _EscapeCommandLineArgumentForMSBuild(s)
+    s = _EscapeMSBuildSpecialCharacters(s)
+    # cl.exe replaces literal # characters with = in preprocessor definitions for
+    # some reason. Octal-encode to work around that.
+    s = s.replace("#", "\\%03o" % ord("#"))
+    return s
+
+
+def _GenerateRulesForMSVS(
+    p, output_dir, options, spec, sources, excluded_sources, actions_to_add
+):
+    """Generate all the rules for a particular project.
+
+  Arguments:
+    p: the project
+    output_dir: directory to emit rules to
+    options: global options passed to the generator
+    spec: the specification for this project
+    sources: the set of all known source files in this project
+    excluded_sources: the set of sources excluded from normal processing
+    actions_to_add: deferred list of actions to add in
+  """
+    rules = spec.get("rules", [])
+    rules_native = [r for r in rules if not int(r.get("msvs_external_rule", 0))]
+    rules_external = [r for r in rules if int(r.get("msvs_external_rule", 0))]
+
+    # Handle rules that use a native rules file.
+    if rules_native:
+        _GenerateNativeRulesForMSVS(p, rules_native, output_dir, spec, options)
+
+    # Handle external rules (non-native rules).
+    if rules_external:
+        _GenerateExternalRules(
+            rules_external, output_dir, spec, sources, options, actions_to_add
+        )
+    _AdjustSourcesForRules(rules, sources, excluded_sources, False)
+
+
+def _AdjustSourcesForRules(rules, sources, excluded_sources, is_msbuild):
+    # Add outputs generated by each rule (if applicable).
+    for rule in rules:
+        # Add in the outputs from this rule.
+        trigger_files = _FindRuleTriggerFiles(rule, sources)
+        for trigger_file in trigger_files:
+            # Remove trigger_file from excluded_sources to let the rule be triggered
+            # (e.g. rule trigger ax_enums.idl is added to excluded_sources
+            # because it's also in an action's inputs in the same project)
+            excluded_sources.discard(_FixPath(trigger_file))
+            # Done if not processing outputs as sources.
+            if int(rule.get("process_outputs_as_sources", False)):
+                inputs, outputs = _RuleInputsAndOutputs(rule, trigger_file)
+                inputs = OrderedSet(_FixPaths(inputs))
+                outputs = OrderedSet(_FixPaths(outputs))
+                inputs.remove(_FixPath(trigger_file))
+                sources.update(inputs)
+                if not is_msbuild:
+                    excluded_sources.update(inputs)
+                sources.update(outputs)
+
+
+def _FilterActionsFromExcluded(excluded_sources, actions_to_add):
+    """Take inputs with actions attached out of the list of exclusions.
+
+  Arguments:
+    excluded_sources: list of source files not to be built.
+    actions_to_add: dict of actions keyed on source file they're attached to.
+  Returns:
+    excluded_sources with files that have actions attached removed.
+  """
+    must_keep = OrderedSet(_FixPaths(actions_to_add.keys()))
+    return [s for s in excluded_sources if s not in must_keep]
+
+
+def _GetDefaultConfiguration(spec):
+    return spec["configurations"][spec["default_configuration"]]
+
+
+def _GetGuidOfProject(proj_path, spec):
+    """Get the guid for the project.
+
+  Arguments:
+    proj_path: Path of the vcproj or vcxproj file to generate.
+    spec: The target dictionary containing the properties of the target.
+  Returns:
+    the guid.
+  Raises:
+    ValueError: if the specified GUID is invalid.
+  """
+    # Pluck out the default configuration.
+    default_config = _GetDefaultConfiguration(spec)
+    # Decide the guid of the project.
+    guid = default_config.get("msvs_guid")
+    if guid:
+        if VALID_MSVS_GUID_CHARS.match(guid) is None:
+            raise ValueError(
+                'Invalid MSVS guid: "%s".  Must match regex: "%s".'
+                % (guid, VALID_MSVS_GUID_CHARS.pattern)
+            )
+        guid = "{%s}" % guid
+    guid = guid or MSVSNew.MakeGuid(proj_path)
+    return guid
+
+
+def _GetMsbuildToolsetOfProject(proj_path, spec, version):
+    """Get the platform toolset for the project.
+
+  Arguments:
+    proj_path: Path of the vcproj or vcxproj file to generate.
+    spec: The target dictionary containing the properties of the target.
+    version: The MSVSVersion object.
+  Returns:
+    the platform toolset string or None.
+  """
+    # Pluck out the default configuration.
+    default_config = _GetDefaultConfiguration(spec)
+    toolset = default_config.get("msbuild_toolset")
+    if not toolset and version.DefaultToolset():
+        toolset = version.DefaultToolset()
+    if spec["type"] == "windows_driver":
+        toolset = "WindowsKernelModeDriver10.0"
+    return toolset
+
+
+def _GenerateProject(project, options, version, generator_flags, spec):
+    """Generates a vcproj file.
+
+  Arguments:
+    project: the MSVSProject object.
+    options: global generator options.
+    version: the MSVSVersion object.
+    generator_flags: dict of generator-specific flags.
+  Returns:
+    A list of source files that cannot be found on disk.
+  """
+    default_config = _GetDefaultConfiguration(project.spec)
+
+    # Skip emitting anything if told to with msvs_existing_vcproj option.
+    if default_config.get("msvs_existing_vcproj"):
+        return []
+
+    if version.UsesVcxproj():
+        return _GenerateMSBuildProject(project, options, version, generator_flags, spec)
+    else:
+        return _GenerateMSVSProject(project, options, version, generator_flags)
+
+
+def _GenerateMSVSProject(project, options, version, generator_flags):
+    """Generates a .vcproj file.  It may create .rules and .user files too.
+
+  Arguments:
+    project: The project object we will generate the file for.
+    options: Global options passed to the generator.
+    version: The VisualStudioVersion object.
+    generator_flags: dict of generator-specific flags.
+  """
+    spec = project.spec
+    gyp.common.EnsureDirExists(project.path)
+
+    platforms = _GetUniquePlatforms(spec)
+    p = MSVSProject.Writer(
+        project.path, version, spec["target_name"], project.guid, platforms
+    )
+
+    # Get directory project file is in.
+    project_dir = os.path.split(project.path)[0]
+    gyp_path = _NormalizedSource(project.build_file)
+    relative_path_of_gyp_file = gyp.common.RelativePath(gyp_path, project_dir)
+
+    config_type = _GetMSVSConfigurationType(spec, project.build_file)
+    for config_name, config in spec["configurations"].items():
+        _AddConfigurationToMSVSProject(p, spec, config_type, config_name, config)
+
+    # Prepare list of sources and excluded sources.
+    gyp_file = os.path.split(project.build_file)[1]
+    sources, excluded_sources = _PrepareListOfSources(spec, generator_flags, gyp_file)
+
+    # Add rules.
+    actions_to_add = {}
+    _GenerateRulesForMSVS(
+        p, project_dir, options, spec, sources, excluded_sources, actions_to_add
+    )
+    list_excluded = generator_flags.get("msvs_list_excluded_files", True)
+    sources, excluded_sources, excluded_idl = _AdjustSourcesAndConvertToFilterHierarchy(
+        spec, options, project_dir, sources, excluded_sources, list_excluded, version
+    )
+
+    # Add in files.
+    missing_sources = _VerifySourcesExist(sources, project_dir)
+    p.AddFiles(sources)
+
+    _AddToolFilesToMSVS(p, spec)
+    _HandlePreCompiledHeaders(p, sources, spec)
+    _AddActions(actions_to_add, spec, relative_path_of_gyp_file)
+    _AddCopies(actions_to_add, spec)
+    _WriteMSVSUserFile(project.path, version, spec)
+
+    # NOTE: this stanza must appear after all actions have been decided.
+    # Don't excluded sources with actions attached, or they won't run.
+    excluded_sources = _FilterActionsFromExcluded(excluded_sources, actions_to_add)
+    _ExcludeFilesFromBeingBuilt(p, spec, excluded_sources, excluded_idl, list_excluded)
+    _AddAccumulatedActionsToMSVS(p, spec, actions_to_add)
+
+    # Write it out.
+    p.WriteIfChanged()
+
+    return missing_sources
+
+
+def _GetUniquePlatforms(spec):
+    """Returns the list of unique platforms for this spec, e.g ['win32', ...].
+
+  Arguments:
+    spec: The target dictionary containing the properties of the target.
+  Returns:
+    The MSVSUserFile object created.
+  """
+    # Gather list of unique platforms.
+    platforms = OrderedSet()
+    for configuration in spec["configurations"]:
+        platforms.add(_ConfigPlatform(spec["configurations"][configuration]))
+    platforms = list(platforms)
+    return platforms
+
+
+def _CreateMSVSUserFile(proj_path, version, spec):
+    """Generates a .user file for the user running this Gyp program.
+
+  Arguments:
+    proj_path: The path of the project file being created.  The .user file
+               shares the same path (with an appropriate suffix).
+    version: The VisualStudioVersion object.
+    spec: The target dictionary containing the properties of the target.
+  Returns:
+    The MSVSUserFile object created.
+  """
+    (domain, username) = _GetDomainAndUserName()
+    vcuser_filename = ".".join([proj_path, domain, username, "user"])
+    user_file = MSVSUserFile.Writer(vcuser_filename, version, spec["target_name"])
+    return user_file
+
+
+def _GetMSVSConfigurationType(spec, build_file):
+    """Returns the configuration type for this project.
+
+  It's a number defined by Microsoft.  May raise an exception.
+
+  Args:
+      spec: The target dictionary containing the properties of the target.
+      build_file: The path of the gyp file.
+  Returns:
+      An integer, the configuration type.
+  """
+    try:
+        config_type = {
+            "executable": "1",  # .exe
+            "shared_library": "2",  # .dll
+            "loadable_module": "2",  # .dll
+            "static_library": "4",  # .lib
+            "windows_driver": "5",  # .sys
+            "none": "10",  # Utility type
+        }[spec["type"]]
+    except KeyError:
+        if spec.get("type"):
+            raise GypError(
+                "Target type %s is not a valid target type for "
+                "target %s in %s." % (spec["type"], spec["target_name"], build_file)
+            )
+        else:
+            raise GypError(
+                "Missing type field for target %s in %s."
+                % (spec["target_name"], build_file)
+            )
+    return config_type
+
+
+def _AddConfigurationToMSVSProject(p, spec, config_type, config_name, config):
+    """Adds a configuration to the MSVS project.
+
+  Many settings in a vcproj file are specific to a configuration.  This
+  function the main part of the vcproj file that's configuration specific.
+
+  Arguments:
+    p: The target project being generated.
+    spec: The target dictionary containing the properties of the target.
+    config_type: The configuration type, a number as defined by Microsoft.
+    config_name: The name of the configuration.
+    config: The dictionary that defines the special processing to be done
+            for this configuration.
+  """
+    # Get the information for this configuration
+    include_dirs, midl_include_dirs, resource_include_dirs = _GetIncludeDirs(config)
+    libraries = _GetLibraries(spec)
+    library_dirs = _GetLibraryDirs(config)
+    out_file, vc_tool, _ = _GetOutputFilePathAndTool(spec, msbuild=False)
+    defines = _GetDefines(config)
+    defines = [_EscapeCppDefineForMSVS(d) for d in defines]
+    disabled_warnings = _GetDisabledWarnings(config)
+    prebuild = config.get("msvs_prebuild")
+    postbuild = config.get("msvs_postbuild")
+    def_file = _GetModuleDefinition(spec)
+    precompiled_header = config.get("msvs_precompiled_header")
+
+    # Prepare the list of tools as a dictionary.
+    tools = dict()
+    # Add in user specified msvs_settings.
+    msvs_settings = config.get("msvs_settings", {})
+    MSVSSettings.ValidateMSVSSettings(msvs_settings)
+
+    # Prevent default library inheritance from the environment.
+    _ToolAppend(tools, "VCLinkerTool", "AdditionalDependencies", ["$(NOINHERIT)"])
+
+    for tool in msvs_settings:
+        settings = config["msvs_settings"][tool]
+        for setting in settings:
+            _ToolAppend(tools, tool, setting, settings[setting])
+    # Add the information to the appropriate tool
+    _ToolAppend(tools, "VCCLCompilerTool", "AdditionalIncludeDirectories", include_dirs)
+    _ToolAppend(tools, "VCMIDLTool", "AdditionalIncludeDirectories", midl_include_dirs)
+    _ToolAppend(
+        tools,
+        "VCResourceCompilerTool",
+        "AdditionalIncludeDirectories",
+        resource_include_dirs,
+    )
+    # Add in libraries.
+    _ToolAppend(tools, "VCLinkerTool", "AdditionalDependencies", libraries)
+    _ToolAppend(tools, "VCLinkerTool", "AdditionalLibraryDirectories", library_dirs)
+    if out_file:
+        _ToolAppend(tools, vc_tool, "OutputFile", out_file, only_if_unset=True)
+    # Add defines.
+    _ToolAppend(tools, "VCCLCompilerTool", "PreprocessorDefinitions", defines)
+    _ToolAppend(tools, "VCResourceCompilerTool", "PreprocessorDefinitions", defines)
+    # Change program database directory to prevent collisions.
+    _ToolAppend(
+        tools,
+        "VCCLCompilerTool",
+        "ProgramDataBaseFileName",
+        "$(IntDir)$(ProjectName)\\vc80.pdb",
+        only_if_unset=True,
+    )
+    # Add disabled warnings.
+    _ToolAppend(tools, "VCCLCompilerTool", "DisableSpecificWarnings", disabled_warnings)
+    # Add Pre-build.
+    _ToolAppend(tools, "VCPreBuildEventTool", "CommandLine", prebuild)
+    # Add Post-build.
+    _ToolAppend(tools, "VCPostBuildEventTool", "CommandLine", postbuild)
+    # Turn on precompiled headers if appropriate.
+    if precompiled_header:
+        precompiled_header = os.path.split(precompiled_header)[1]
+        _ToolAppend(tools, "VCCLCompilerTool", "UsePrecompiledHeader", "2")
+        _ToolAppend(
+            tools, "VCCLCompilerTool", "PrecompiledHeaderThrough", precompiled_header
+        )
+        _ToolAppend(tools, "VCCLCompilerTool", "ForcedIncludeFiles", precompiled_header)
+    # Loadable modules don't generate import libraries;
+    # tell dependent projects to not expect one.
+    if spec["type"] == "loadable_module":
+        _ToolAppend(tools, "VCLinkerTool", "IgnoreImportLibrary", "true")
+    # Set the module definition file if any.
+    if def_file:
+        _ToolAppend(tools, "VCLinkerTool", "ModuleDefinitionFile", def_file)
+
+    _AddConfigurationToMSVS(p, spec, tools, config, config_type, config_name)
+
+
+def _GetIncludeDirs(config):
+    """Returns the list of directories to be used for #include directives.
+
+  Arguments:
+    config: The dictionary that defines the special processing to be done
+            for this configuration.
+  Returns:
+    The list of directory paths.
+  """
+    # TODO(bradnelson): include_dirs should really be flexible enough not to
+    #                   require this sort of thing.
+    include_dirs = config.get("include_dirs", []) + config.get(
+        "msvs_system_include_dirs", []
+    )
+    midl_include_dirs = config.get("midl_include_dirs", []) + config.get(
+        "msvs_system_include_dirs", []
+    )
+    resource_include_dirs = config.get("resource_include_dirs", include_dirs)
+    include_dirs = _FixPaths(include_dirs)
+    midl_include_dirs = _FixPaths(midl_include_dirs)
+    resource_include_dirs = _FixPaths(resource_include_dirs)
+    return include_dirs, midl_include_dirs, resource_include_dirs
+
+
+def _GetLibraryDirs(config):
+    """Returns the list of directories to be used for library search paths.
+
+  Arguments:
+    config: The dictionary that defines the special processing to be done
+            for this configuration.
+  Returns:
+    The list of directory paths.
+  """
+
+    library_dirs = config.get("library_dirs", [])
+    library_dirs = _FixPaths(library_dirs)
+    return library_dirs
+
+
+def _GetLibraries(spec):
+    """Returns the list of libraries for this configuration.
+
+  Arguments:
+    spec: The target dictionary containing the properties of the target.
+  Returns:
+    The list of directory paths.
+  """
+    libraries = spec.get("libraries", [])
+    # Strip out -l, as it is not used on windows (but is needed so we can pass
+    # in libraries that are assumed to be in the default library path).
+    # Also remove duplicate entries, leaving only the last duplicate, while
+    # preserving order.
+    found = OrderedSet()
+    unique_libraries_list = []
+    for entry in reversed(libraries):
+        library = re.sub(r"^\-l", "", entry)
+        if not os.path.splitext(library)[1]:
+            library += ".lib"
+        if library not in found:
+            found.add(library)
+            unique_libraries_list.append(library)
+    unique_libraries_list.reverse()
+    return unique_libraries_list
+
+
+def _GetOutputFilePathAndTool(spec, msbuild):
+    """Returns the path and tool to use for this target.
+
+  Figures out the path of the file this spec will create and the name of
+  the VC tool that will create it.
+
+  Arguments:
+    spec: The target dictionary containing the properties of the target.
+  Returns:
+    A triple of (file path, name of the vc tool, name of the msbuild tool)
+  """
+    # Select a name for the output file.
+    out_file = ""
+    vc_tool = ""
+    msbuild_tool = ""
+    output_file_map = {
+        "executable": ("VCLinkerTool", "Link", "$(OutDir)", ".exe"),
+        "shared_library": ("VCLinkerTool", "Link", "$(OutDir)", ".dll"),
+        "loadable_module": ("VCLinkerTool", "Link", "$(OutDir)", ".dll"),
+        "windows_driver": ("VCLinkerTool", "Link", "$(OutDir)", ".sys"),
+        "static_library": ("VCLibrarianTool", "Lib", "$(OutDir)lib\\", ".lib"),
+    }
+    output_file_props = output_file_map.get(spec["type"])
+    if output_file_props and int(spec.get("msvs_auto_output_file", 1)):
+        vc_tool, msbuild_tool, out_dir, suffix = output_file_props
+        if spec.get("standalone_static_library", 0):
+            out_dir = "$(OutDir)"
+        out_dir = spec.get("product_dir", out_dir)
+        product_extension = spec.get("product_extension")
+        if product_extension:
+            suffix = "." + product_extension
+        elif msbuild:
+            suffix = "$(TargetExt)"
+        prefix = spec.get("product_prefix", "")
+        product_name = spec.get("product_name", "$(ProjectName)")
+        out_file = ntpath.join(out_dir, prefix + product_name + suffix)
+    return out_file, vc_tool, msbuild_tool
+
+
+def _GetOutputTargetExt(spec):
+    """Returns the extension for this target, including the dot
+
+  If product_extension is specified, set target_extension to this to avoid
+  MSB8012, returns None otherwise. Ignores any target_extension settings in
+  the input files.
+
+  Arguments:
+    spec: The target dictionary containing the properties of the target.
+  Returns:
+    A string with the extension, or None
+  """
+    target_extension = spec.get("product_extension")
+    if target_extension:
+        return "." + target_extension
+    return None
+
+
+def _GetDefines(config):
+    """Returns the list of preprocessor definitions for this configuration.
+
+  Arguments:
+    config: The dictionary that defines the special processing to be done
+            for this configuration.
+  Returns:
+    The list of preprocessor definitions.
+  """
+    defines = []
+    for d in config.get("defines", []):
+        if type(d) == list:
+            fd = "=".join([str(dpart) for dpart in d])
+        else:
+            fd = str(d)
+        defines.append(fd)
+    return defines
+
+
+def _GetDisabledWarnings(config):
+    return [str(i) for i in config.get("msvs_disabled_warnings", [])]
+
+
+def _GetModuleDefinition(spec):
+    def_file = ""
+    if spec["type"] in [
+        "shared_library",
+        "loadable_module",
+        "executable",
+        "windows_driver",
+    ]:
+        def_files = [s for s in spec.get("sources", []) if s.endswith(".def")]
+        if len(def_files) == 1:
+            def_file = _FixPath(def_files[0])
+        elif def_files:
+            raise ValueError(
+                "Multiple module definition files in one target, target %s lists "
+                "multiple .def files: %s" % (spec["target_name"], " ".join(def_files))
+            )
+    return def_file
+
+
+def _ConvertToolsToExpectedForm(tools):
+    """Convert tools to a form expected by Visual Studio.
+
+  Arguments:
+    tools: A dictionary of settings; the tool name is the key.
+  Returns:
+    A list of Tool objects.
+  """
+    tool_list = []
+    for tool, settings in tools.items():
+        # Collapse settings with lists.
+        settings_fixed = {}
+        for setting, value in settings.items():
+            if type(value) == list:
+                if (
+                    tool == "VCLinkerTool" and setting == "AdditionalDependencies"
+                ) or setting == "AdditionalOptions":
+                    settings_fixed[setting] = " ".join(value)
+                else:
+                    settings_fixed[setting] = ";".join(value)
+            else:
+                settings_fixed[setting] = value
+        # Add in this tool.
+        tool_list.append(MSVSProject.Tool(tool, settings_fixed))
+    return tool_list
+
+
+def _AddConfigurationToMSVS(p, spec, tools, config, config_type, config_name):
+    """Add to the project file the configuration specified by config.
+
+  Arguments:
+    p: The target project being generated.
+    spec: the target project dict.
+    tools: A dictionary of settings; the tool name is the key.
+    config: The dictionary that defines the special processing to be done
+            for this configuration.
+    config_type: The configuration type, a number as defined by Microsoft.
+    config_name: The name of the configuration.
+  """
+    attributes = _GetMSVSAttributes(spec, config, config_type)
+    # Add in this configuration.
+    tool_list = _ConvertToolsToExpectedForm(tools)
+    p.AddConfig(_ConfigFullName(config_name, config), attrs=attributes, tools=tool_list)
+
+
+def _GetMSVSAttributes(spec, config, config_type):
+    # Prepare configuration attributes.
+    prepared_attrs = {}
+    source_attrs = config.get("msvs_configuration_attributes", {})
+    for a in source_attrs:
+        prepared_attrs[a] = source_attrs[a]
+    # Add props files.
+    vsprops_dirs = config.get("msvs_props", [])
+    vsprops_dirs = _FixPaths(vsprops_dirs)
+    if vsprops_dirs:
+        prepared_attrs["InheritedPropertySheets"] = ";".join(vsprops_dirs)
+    # Set configuration type.
+    prepared_attrs["ConfigurationType"] = config_type
+    output_dir = prepared_attrs.get(
+        "OutputDirectory", "$(SolutionDir)$(ConfigurationName)"
+    )
+    prepared_attrs["OutputDirectory"] = _FixPath(output_dir) + "\\"
+    if "IntermediateDirectory" not in prepared_attrs:
+        intermediate = "$(ConfigurationName)\\obj\\$(ProjectName)"
+        prepared_attrs["IntermediateDirectory"] = _FixPath(intermediate) + "\\"
+    else:
+        intermediate = _FixPath(prepared_attrs["IntermediateDirectory"]) + "\\"
+        intermediate = MSVSSettings.FixVCMacroSlashes(intermediate)
+        prepared_attrs["IntermediateDirectory"] = intermediate
+    return prepared_attrs
+
+
+def _AddNormalizedSources(sources_set, sources_array):
+    sources_set.update(_NormalizedSource(s) for s in sources_array)
+
+
+def _PrepareListOfSources(spec, generator_flags, gyp_file):
+    """Prepare list of sources and excluded sources.
+
+  Besides the sources specified directly in the spec, adds the gyp file so
+  that a change to it will cause a re-compile. Also adds appropriate sources
+  for actions and copies. Assumes later stage will un-exclude files which
+  have custom build steps attached.
+
+  Arguments:
+    spec: The target dictionary containing the properties of the target.
+    gyp_file: The name of the gyp file.
+  Returns:
+    A pair of (list of sources, list of excluded sources).
+    The sources will be relative to the gyp file.
+  """
+    sources = OrderedSet()
+    _AddNormalizedSources(sources, spec.get("sources", []))
+    excluded_sources = OrderedSet()
+    # Add in the gyp file.
+    if not generator_flags.get("standalone"):
+        sources.add(gyp_file)
+
+    # Add in 'action' inputs and outputs.
+    for a in spec.get("actions", []):
+        inputs = a["inputs"]
+        inputs = [_NormalizedSource(i) for i in inputs]
+        # Add all inputs to sources and excluded sources.
+        inputs = OrderedSet(inputs)
+        sources.update(inputs)
+        if not spec.get("msvs_external_builder"):
+            excluded_sources.update(inputs)
+        if int(a.get("process_outputs_as_sources", False)):
+            _AddNormalizedSources(sources, a.get("outputs", []))
+    # Add in 'copies' inputs and outputs.
+    for cpy in spec.get("copies", []):
+        _AddNormalizedSources(sources, cpy.get("files", []))
+    return (sources, excluded_sources)
+
+
+def _AdjustSourcesAndConvertToFilterHierarchy(
+    spec, options, gyp_dir, sources, excluded_sources, list_excluded, version
+):
+    """Adjusts the list of sources and excluded sources.
+
+  Also converts the sets to lists.
+
+  Arguments:
+    spec: The target dictionary containing the properties of the target.
+    options: Global generator options.
+    gyp_dir: The path to the gyp file being processed.
+    sources: A set of sources to be included for this project.
+    excluded_sources: A set of sources to be excluded for this project.
+    version: A MSVSVersion object.
+  Returns:
+    A trio of (list of sources, list of excluded sources,
+               path of excluded IDL file)
+  """
+    # Exclude excluded sources coming into the generator.
+    excluded_sources.update(OrderedSet(spec.get("sources_excluded", [])))
+    # Add excluded sources into sources for good measure.
+    sources.update(excluded_sources)
+    # Convert to proper windows form.
+    # NOTE: sources goes from being a set to a list here.
+    # NOTE: excluded_sources goes from being a set to a list here.
+    sources = _FixPaths(sources)
+    # Convert to proper windows form.
+    excluded_sources = _FixPaths(excluded_sources)
+
+    excluded_idl = _IdlFilesHandledNonNatively(spec, sources)
+
+    precompiled_related = _GetPrecompileRelatedFiles(spec)
+    # Find the excluded ones, minus the precompiled header related ones.
+    fully_excluded = [i for i in excluded_sources if i not in precompiled_related]
+
+    # Convert to folders and the right slashes.
+    sources = [i.split("\\") for i in sources]
+    sources = _ConvertSourcesToFilterHierarchy(
+        sources,
+        excluded=fully_excluded,
+        list_excluded=list_excluded,
+        msvs_version=version,
+    )
+
+    # Prune filters with a single child to flatten ugly directory structures
+    # such as ../../src/modules/module1 etc.
+    if version.UsesVcxproj():
+        while (
+            all([isinstance(s, MSVSProject.Filter) for s in sources])
+            and len({s.name for s in sources}) == 1
+        ):
+            assert all([len(s.contents) == 1 for s in sources])
+            sources = [s.contents[0] for s in sources]
+    else:
+        while len(sources) == 1 and isinstance(sources[0], MSVSProject.Filter):
+            sources = sources[0].contents
+
+    return sources, excluded_sources, excluded_idl
+
+
+def _IdlFilesHandledNonNatively(spec, sources):
+    # If any non-native rules use 'idl' as an extension exclude idl files.
+    # Gather a list here to use later.
+    using_idl = False
+    for rule in spec.get("rules", []):
+        if rule["extension"] == "idl" and int(rule.get("msvs_external_rule", 0)):
+            using_idl = True
+            break
+    if using_idl:
+        excluded_idl = [i for i in sources if i.endswith(".idl")]
+    else:
+        excluded_idl = []
+    return excluded_idl
+
+
+def _GetPrecompileRelatedFiles(spec):
+    # Gather a list of precompiled header related sources.
+    precompiled_related = []
+    for _, config in spec["configurations"].items():
+        for k in precomp_keys:
+            f = config.get(k)
+            if f:
+                precompiled_related.append(_FixPath(f))
+    return precompiled_related
+
+
+def _ExcludeFilesFromBeingBuilt(p, spec, excluded_sources, excluded_idl, list_excluded):
+    exclusions = _GetExcludedFilesFromBuild(spec, excluded_sources, excluded_idl)
+    for file_name, excluded_configs in exclusions.items():
+        if not list_excluded and len(excluded_configs) == len(spec["configurations"]):
+            # If we're not listing excluded files, then they won't appear in the
+            # project, so don't try to configure them to be excluded.
+            pass
+        else:
+            for config_name, config in excluded_configs:
+                p.AddFileConfig(
+                    file_name,
+                    _ConfigFullName(config_name, config),
+                    {"ExcludedFromBuild": "true"},
+                )
+
+
+def _GetExcludedFilesFromBuild(spec, excluded_sources, excluded_idl):
+    exclusions = {}
+    # Exclude excluded sources from being built.
+    for f in excluded_sources:
+        excluded_configs = []
+        for config_name, config in spec["configurations"].items():
+            precomped = [_FixPath(config.get(i, "")) for i in precomp_keys]
+            # Don't do this for ones that are precompiled header related.
+            if f not in precomped:
+                excluded_configs.append((config_name, config))
+        exclusions[f] = excluded_configs
+    # If any non-native rules use 'idl' as an extension exclude idl files.
+    # Exclude them now.
+    for f in excluded_idl:
+        excluded_configs = []
+        for config_name, config in spec["configurations"].items():
+            excluded_configs.append((config_name, config))
+        exclusions[f] = excluded_configs
+    return exclusions
+
+
+def _AddToolFilesToMSVS(p, spec):
+    # Add in tool files (rules).
+    tool_files = OrderedSet()
+    for _, config in spec["configurations"].items():
+        for f in config.get("msvs_tool_files", []):
+            tool_files.add(f)
+    for f in tool_files:
+        p.AddToolFile(f)
+
+
+def _HandlePreCompiledHeaders(p, sources, spec):
+    # Pre-compiled header source stubs need a different compiler flag
+    # (generate precompiled header) and any source file not of the same
+    # kind (i.e. C vs. C++) as the precompiled header source stub needs
+    # to have use of precompiled headers disabled.
+    extensions_excluded_from_precompile = []
+    for config_name, config in spec["configurations"].items():
+        source = config.get("msvs_precompiled_source")
+        if source:
+            source = _FixPath(source)
+            # UsePrecompiledHeader=1 for if using precompiled headers.
+            tool = MSVSProject.Tool("VCCLCompilerTool", {"UsePrecompiledHeader": "1"})
+            p.AddFileConfig(
+                source, _ConfigFullName(config_name, config), {}, tools=[tool]
+            )
+            basename, extension = os.path.splitext(source)
+            if extension == ".c":
+                extensions_excluded_from_precompile = [".cc", ".cpp", ".cxx"]
+            else:
+                extensions_excluded_from_precompile = [".c"]
+
+    def DisableForSourceTree(source_tree):
+        for source in source_tree:
+            if isinstance(source, MSVSProject.Filter):
+                DisableForSourceTree(source.contents)
+            else:
+                basename, extension = os.path.splitext(source)
+                if extension in extensions_excluded_from_precompile:
+                    for config_name, config in spec["configurations"].items():
+                        tool = MSVSProject.Tool(
+                            "VCCLCompilerTool",
+                            {
+                                "UsePrecompiledHeader": "0",
+                                "ForcedIncludeFiles": "$(NOINHERIT)",
+                            },
+                        )
+                        p.AddFileConfig(
+                            _FixPath(source),
+                            _ConfigFullName(config_name, config),
+                            {},
+                            tools=[tool],
+                        )
+
+    # Do nothing if there was no precompiled source.
+    if extensions_excluded_from_precompile:
+        DisableForSourceTree(sources)
+
+
+def _AddActions(actions_to_add, spec, relative_path_of_gyp_file):
+    # Add actions.
+    actions = spec.get("actions", [])
+    # Don't setup_env every time. When all the actions are run together in one
+    # batch file in VS, the PATH will grow too long.
+    # Membership in this set means that the cygwin environment has been set up,
+    # and does not need to be set up again.
+    have_setup_env = set()
+    for a in actions:
+        # Attach actions to the gyp file if nothing else is there.
+        inputs = a.get("inputs") or [relative_path_of_gyp_file]
+        attached_to = inputs[0]
+        need_setup_env = attached_to not in have_setup_env
+        cmd = _BuildCommandLineForRule(
+            spec, a, has_input_path=False, do_setup_env=need_setup_env
+        )
+        have_setup_env.add(attached_to)
+        # Add the action.
+        _AddActionStep(
+            actions_to_add,
+            inputs=inputs,
+            outputs=a.get("outputs", []),
+            description=a.get("message", a["action_name"]),
+            command=cmd,
+        )
+
+
+def _WriteMSVSUserFile(project_path, version, spec):
+    # Add run_as and test targets.
+    if "run_as" in spec:
+        run_as = spec["run_as"]
+        action = run_as.get("action", [])
+        environment = run_as.get("environment", [])
+        working_directory = run_as.get("working_directory", ".")
+    elif int(spec.get("test", 0)):
+        action = ["$(TargetPath)", "--gtest_print_time"]
+        environment = []
+        working_directory = "."
+    else:
+        return  # Nothing to add
+    # Write out the user file.
+    user_file = _CreateMSVSUserFile(project_path, version, spec)
+    for config_name, c_data in spec["configurations"].items():
+        user_file.AddDebugSettings(
+            _ConfigFullName(config_name, c_data), action, environment, working_directory
+        )
+    user_file.WriteIfChanged()
+
+
+def _AddCopies(actions_to_add, spec):
+    copies = _GetCopies(spec)
+    for inputs, outputs, cmd, description in copies:
+        _AddActionStep(
+            actions_to_add,
+            inputs=inputs,
+            outputs=outputs,
+            description=description,
+            command=cmd,
+        )
+
+
+def _GetCopies(spec):
+    copies = []
+    # Add copies.
+    for cpy in spec.get("copies", []):
+        for src in cpy.get("files", []):
+            dst = os.path.join(cpy["destination"], os.path.basename(src))
+            # _AddCustomBuildToolForMSVS() will call _FixPath() on the inputs and
+            # outputs, so do the same for our generated command line.
+            if src.endswith("/"):
+                src_bare = src[:-1]
+                base_dir = posixpath.split(src_bare)[0]
+                outer_dir = posixpath.split(src_bare)[1]
+                fixed_dst = _FixPath(dst)
+                full_dst = f'"{fixed_dst}\\{outer_dir}\\"'
+                cmd = 'mkdir {} 2>nul & cd "{}" && xcopy /e /f /y "{}" {}'.format(
+                    full_dst,
+                    _FixPath(base_dir),
+                    outer_dir,
+                    full_dst,
+                )
+                copies.append(
+                    (
+                        [src],
+                        ["dummy_copies", dst],
+                        cmd,
+                        f"Copying {src} to {fixed_dst}",
+                    )
+                )
+            else:
+                fix_dst = _FixPath(cpy["destination"])
+                cmd = 'mkdir "{}" 2>nul & set ERRORLEVEL=0 & copy /Y "{}" "{}"'.format(
+                    fix_dst,
+                    _FixPath(src),
+                    _FixPath(dst),
+                )
+                copies.append(([src], [dst], cmd, f"Copying {src} to {fix_dst}"))
+    return copies
+
+
+def _GetPathDict(root, path):
+    # |path| will eventually be empty (in the recursive calls) if it was initially
+    # relative; otherwise it will eventually end up as '\', 'D:\', etc.
+    if not path or path.endswith(os.sep):
+        return root
+    parent, folder = os.path.split(path)
+    parent_dict = _GetPathDict(root, parent)
+    if folder not in parent_dict:
+        parent_dict[folder] = dict()
+    return parent_dict[folder]
+
+
+def _DictsToFolders(base_path, bucket, flat):
+    # Convert to folders recursively.
+    children = []
+    for folder, contents in bucket.items():
+        if type(contents) == dict:
+            folder_children = _DictsToFolders(
+                os.path.join(base_path, folder), contents, flat
+            )
+            if flat:
+                children += folder_children
+            else:
+                folder_children = MSVSNew.MSVSFolder(
+                    os.path.join(base_path, folder),
+                    name="(" + folder + ")",
+                    entries=folder_children,
+                )
+                children.append(folder_children)
+        else:
+            children.append(contents)
+    return children
+
+
+def _CollapseSingles(parent, node):
+    # Recursively explorer the tree of dicts looking for projects which are
+    # the sole item in a folder which has the same name as the project. Bring
+    # such projects up one level.
+    if type(node) == dict and len(node) == 1 and next(iter(node)) == parent + ".vcproj":
+        return node[next(iter(node))]
+    if type(node) != dict:
+        return node
+    for child in node:
+        node[child] = _CollapseSingles(child, node[child])
+    return node
+
+
+def _GatherSolutionFolders(sln_projects, project_objects, flat):
+    root = {}
+    # Convert into a tree of dicts on path.
+    for p in sln_projects:
+        gyp_file, target = gyp.common.ParseQualifiedTarget(p)[0:2]
+        if p.endswith("#host"):
+            target += "_host"
+        gyp_dir = os.path.dirname(gyp_file)
+        path_dict = _GetPathDict(root, gyp_dir)
+        path_dict[target + ".vcproj"] = project_objects[p]
+    # Walk down from the top until we hit a folder that has more than one entry.
+    # In practice, this strips the top-level "src/" dir from the hierarchy in
+    # the solution.
+    while len(root) == 1 and type(root[next(iter(root))]) == dict:
+        root = root[next(iter(root))]
+    # Collapse singles.
+    root = _CollapseSingles("", root)
+    # Merge buckets until everything is a root entry.
+    return _DictsToFolders("", root, flat)
+
+
+def _GetPathOfProject(qualified_target, spec, options, msvs_version):
+    default_config = _GetDefaultConfiguration(spec)
+    proj_filename = default_config.get("msvs_existing_vcproj")
+    if not proj_filename:
+        proj_filename = spec["target_name"]
+        if spec["toolset"] == "host":
+            proj_filename += "_host"
+        proj_filename = proj_filename + options.suffix + msvs_version.ProjectExtension()
+
+    build_file = gyp.common.BuildFile(qualified_target)
+    proj_path = os.path.join(os.path.dirname(build_file), proj_filename)
+    fix_prefix = None
+    if options.generator_output:
+        project_dir_path = os.path.dirname(os.path.abspath(proj_path))
+        proj_path = os.path.join(options.generator_output, proj_path)
+        fix_prefix = gyp.common.RelativePath(
+            project_dir_path, os.path.dirname(proj_path)
+        )
+    return proj_path, fix_prefix
+
+
+def _GetPlatformOverridesOfProject(spec):
+    # Prepare a dict indicating which project configurations are used for which
+    # solution configurations for this target.
+    config_platform_overrides = {}
+    for config_name, c in spec["configurations"].items():
+        config_fullname = _ConfigFullName(config_name, c)
+        platform = c.get("msvs_target_platform", _ConfigPlatform(c))
+        fixed_config_fullname = "{}|{}".format(
+            _ConfigBaseName(config_name, _ConfigPlatform(c)),
+            platform,
+        )
+        if spec["toolset"] == "host" and generator_supports_multiple_toolsets:
+            fixed_config_fullname = f"{config_name}|x64"
+        config_platform_overrides[config_fullname] = fixed_config_fullname
+    return config_platform_overrides
+
+
+def _CreateProjectObjects(target_list, target_dicts, options, msvs_version):
+    """Create a MSVSProject object for the targets found in target list.
+
+  Arguments:
+    target_list: the list of targets to generate project objects for.
+    target_dicts: the dictionary of specifications.
+    options: global generator options.
+    msvs_version: the MSVSVersion object.
+  Returns:
+    A set of created projects, keyed by target.
+  """
+    global fixpath_prefix
+    # Generate each project.
+    projects = {}
+    for qualified_target in target_list:
+        spec = target_dicts[qualified_target]
+        proj_path, fixpath_prefix = _GetPathOfProject(
+            qualified_target, spec, options, msvs_version
+        )
+        guid = _GetGuidOfProject(proj_path, spec)
+        overrides = _GetPlatformOverridesOfProject(spec)
+        build_file = gyp.common.BuildFile(qualified_target)
+        # Create object for this project.
+        target_name = spec["target_name"]
+        if spec["toolset"] == "host":
+            target_name += "_host"
+        obj = MSVSNew.MSVSProject(
+            proj_path,
+            name=target_name,
+            guid=guid,
+            spec=spec,
+            build_file=build_file,
+            config_platform_overrides=overrides,
+            fixpath_prefix=fixpath_prefix,
+        )
+        # Set project toolset if any (MS build only)
+        if msvs_version.UsesVcxproj():
+            obj.set_msbuild_toolset(
+                _GetMsbuildToolsetOfProject(proj_path, spec, msvs_version)
+            )
+        projects[qualified_target] = obj
+    # Set all the dependencies, but not if we are using an external builder like
+    # ninja
+    for project in projects.values():
+        if not project.spec.get("msvs_external_builder"):
+            deps = project.spec.get("dependencies", [])
+            deps = [projects[d] for d in deps]
+            project.set_dependencies(deps)
+    return projects
+
+
+def _InitNinjaFlavor(params, target_list, target_dicts):
+    """Initialize targets for the ninja flavor.
+
+  This sets up the necessary variables in the targets to generate msvs projects
+  that use ninja as an external builder. The variables in the spec are only set
+  if they have not been set. This allows individual specs to override the
+  default values initialized here.
+  Arguments:
+    params: Params provided to the generator.
+    target_list: List of target pairs: 'base/base.gyp:base'.
+    target_dicts: Dict of target properties keyed on target pair.
+  """
+    for qualified_target in target_list:
+        spec = target_dicts[qualified_target]
+        if spec.get("msvs_external_builder"):
+            # The spec explicitly defined an external builder, so don't change it.
+            continue
+
+        path_to_ninja = spec.get("msvs_path_to_ninja", "ninja.exe")
+
+        spec["msvs_external_builder"] = "ninja"
+        if not spec.get("msvs_external_builder_out_dir"):
+            gyp_file, _, _ = gyp.common.ParseQualifiedTarget(qualified_target)
+            gyp_dir = os.path.dirname(gyp_file)
+            configuration = "$(Configuration)"
+            if params.get("target_arch") == "x64":
+                configuration += "_x64"
+            if params.get("target_arch") == "arm64":
+                configuration += "_arm64"
+            spec["msvs_external_builder_out_dir"] = os.path.join(
+                gyp.common.RelativePath(params["options"].toplevel_dir, gyp_dir),
+                ninja_generator.ComputeOutputDir(params),
+                configuration,
+            )
+        if not spec.get("msvs_external_builder_build_cmd"):
+            spec["msvs_external_builder_build_cmd"] = [
+                path_to_ninja,
+                "-C",
+                "$(OutDir)",
+                "$(ProjectName)",
+            ]
+        if not spec.get("msvs_external_builder_clean_cmd"):
+            spec["msvs_external_builder_clean_cmd"] = [
+                path_to_ninja,
+                "-C",
+                "$(OutDir)",
+                "-tclean",
+                "$(ProjectName)",
+            ]
+
+
+def CalculateVariables(default_variables, params):
+    """Generated variables that require params to be known."""
+
+    generator_flags = params.get("generator_flags", {})
+
+    # Select project file format version (if unset, default to auto detecting).
+    msvs_version = MSVSVersion.SelectVisualStudioVersion(
+        generator_flags.get("msvs_version", "auto")
+    )
+    # Stash msvs_version for later (so we don't have to probe the system twice).
+    params["msvs_version"] = msvs_version
+
+    # Set a variable so conditions can be based on msvs_version.
+    default_variables["MSVS_VERSION"] = msvs_version.ShortName()
+
+    # To determine processor word size on Windows, in addition to checking
+    # PROCESSOR_ARCHITECTURE (which reflects the word size of the current
+    # process), it is also necessary to check PROCESSOR_ARCITEW6432 (which
+    # contains the actual word size of the system when running thru WOW64).
+    if (
+        os.environ.get("PROCESSOR_ARCHITECTURE", "").find("64") >= 0
+        or os.environ.get("PROCESSOR_ARCHITEW6432", "").find("64") >= 0
+    ):
+        default_variables["MSVS_OS_BITS"] = 64
+    else:
+        default_variables["MSVS_OS_BITS"] = 32
+
+    if gyp.common.GetFlavor(params) == "ninja":
+        default_variables["SHARED_INTERMEDIATE_DIR"] = "$(OutDir)gen"
+
+
+def PerformBuild(data, configurations, params):
+    options = params["options"]
+    msvs_version = params["msvs_version"]
+    devenv = os.path.join(msvs_version.path, "Common7", "IDE", "devenv.com")
+
+    for build_file, build_file_dict in data.items():
+        (build_file_root, build_file_ext) = os.path.splitext(build_file)
+        if build_file_ext != ".gyp":
+            continue
+        sln_path = build_file_root + options.suffix + ".sln"
+        if options.generator_output:
+            sln_path = os.path.join(options.generator_output, sln_path)
+
+    for config in configurations:
+        arguments = [devenv, sln_path, "/Build", config]
+        print(f"Building [{config}]: {arguments}")
+        subprocess.check_call(arguments)
+
+
+def CalculateGeneratorInputInfo(params):
+    if params.get("flavor") == "ninja":
+        toplevel = params["options"].toplevel_dir
+        qualified_out_dir = os.path.normpath(
+            os.path.join(
+                toplevel,
+                ninja_generator.ComputeOutputDir(params),
+                "gypfiles-msvs-ninja",
+            )
+        )
+
+        global generator_filelist_paths
+        generator_filelist_paths = {
+            "toplevel": toplevel,
+            "qualified_out_dir": qualified_out_dir,
+        }
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    """Generate .sln and .vcproj files.
+
+  This is the entry point for this generator.
+  Arguments:
+    target_list: List of target pairs: 'base/base.gyp:base'.
+    target_dicts: Dict of target properties keyed on target pair.
+    data: Dictionary containing per .gyp data.
+  """
+    global fixpath_prefix
+
+    options = params["options"]
+
+    # Get the project file format version back out of where we stashed it in
+    # GeneratorCalculatedVariables.
+    msvs_version = params["msvs_version"]
+
+    generator_flags = params.get("generator_flags", {})
+
+    # Optionally shard targets marked with 'msvs_shard': SHARD_COUNT.
+    (target_list, target_dicts) = MSVSUtil.ShardTargets(target_list, target_dicts)
+
+    # Optionally use the large PDB workaround for targets marked with
+    # 'msvs_large_pdb': 1.
+    (target_list, target_dicts) = MSVSUtil.InsertLargePdbShims(
+        target_list, target_dicts, generator_default_variables
+    )
+
+    # Optionally configure each spec to use ninja as the external builder.
+    if params.get("flavor") == "ninja":
+        _InitNinjaFlavor(params, target_list, target_dicts)
+
+    # Prepare the set of configurations.
+    configs = set()
+    for qualified_target in target_list:
+        spec = target_dicts[qualified_target]
+        for config_name, config in spec["configurations"].items():
+            config_name = _ConfigFullName(config_name, config)
+            configs.add(config_name)
+            if config_name == "Release|arm64":
+                configs.add("Release|x64")
+    configs = list(configs)
+
+    # Figure out all the projects that will be generated and their guids
+    project_objects = _CreateProjectObjects(
+        target_list, target_dicts, options, msvs_version
+    )
+
+    # Generate each project.
+    missing_sources = []
+    for project in project_objects.values():
+        fixpath_prefix = project.fixpath_prefix
+        missing_sources.extend(
+            _GenerateProject(project, options, msvs_version, generator_flags, spec)
+        )
+    fixpath_prefix = None
+
+    for build_file in data:
+        # Validate build_file extension
+        target_only_configs = configs
+        if generator_supports_multiple_toolsets:
+            target_only_configs = [i for i in configs if i.endswith("arm64")]
+        if not build_file.endswith(".gyp"):
+            continue
+        sln_path = os.path.splitext(build_file)[0] + options.suffix + ".sln"
+        if options.generator_output:
+            sln_path = os.path.join(options.generator_output, sln_path)
+        # Get projects in the solution, and their dependents.
+        sln_projects = gyp.common.BuildFileTargets(target_list, build_file)
+        sln_projects += gyp.common.DeepDependencyTargets(target_dicts, sln_projects)
+        # Create folder hierarchy.
+        root_entries = _GatherSolutionFolders(
+            sln_projects, project_objects, flat=msvs_version.FlatSolution()
+        )
+        # Create solution.
+        sln = MSVSNew.MSVSSolution(
+            sln_path,
+            entries=root_entries,
+            variants=target_only_configs,
+            websiteProperties=False,
+            version=msvs_version,
+        )
+        sln.Write()
+
+    if missing_sources:
+        error_message = "Missing input files:\n" + "\n".join(set(missing_sources))
+        if generator_flags.get("msvs_error_on_missing_sources", False):
+            raise GypError(error_message)
+        else:
+            print("Warning: " + error_message, file=sys.stdout)
+
+
+def _GenerateMSBuildFiltersFile(
+    filters_path,
+    source_files,
+    rule_dependencies,
+    extension_to_rule_name,
+    platforms,
+    toolset,
+):
+    """Generate the filters file.
+
+  This file is used by Visual Studio to organize the presentation of source
+  files into folders.
+
+  Arguments:
+      filters_path: The path of the file to be created.
+      source_files: The hierarchical structure of all the sources.
+      extension_to_rule_name: A dictionary mapping file extensions to rules.
+  """
+    filter_group = []
+    source_group = []
+    _AppendFiltersForMSBuild(
+        "",
+        source_files,
+        rule_dependencies,
+        extension_to_rule_name,
+        platforms,
+        toolset,
+        filter_group,
+        source_group,
+    )
+    if filter_group:
+        content = [
+            "Project",
+            {
+                "ToolsVersion": "4.0",
+                "xmlns": "http://schemas.microsoft.com/developer/msbuild/2003",
+            },
+            ["ItemGroup"] + filter_group,
+            ["ItemGroup"] + source_group,
+        ]
+        easy_xml.WriteXmlIfChanged(content, filters_path, pretty=True, win32=True)
+    elif os.path.exists(filters_path):
+        # We don't need this filter anymore.  Delete the old filter file.
+        os.unlink(filters_path)
+
+
+def _AppendFiltersForMSBuild(
+    parent_filter_name,
+    sources,
+    rule_dependencies,
+    extension_to_rule_name,
+    platforms,
+    toolset,
+    filter_group,
+    source_group,
+):
+    """Creates the list of filters and sources to be added in the filter file.
+
+  Args:
+      parent_filter_name: The name of the filter under which the sources are
+          found.
+      sources: The hierarchy of filters and sources to process.
+      extension_to_rule_name: A dictionary mapping file extensions to rules.
+      filter_group: The list to which filter entries will be appended.
+      source_group: The list to which source entries will be appended.
+  """
+    for source in sources:
+        if isinstance(source, MSVSProject.Filter):
+            # We have a sub-filter.  Create the name of that sub-filter.
+            if not parent_filter_name:
+                filter_name = source.name
+            else:
+                filter_name = f"{parent_filter_name}\\{source.name}"
+            # Add the filter to the group.
+            filter_group.append(
+                [
+                    "Filter",
+                    {"Include": filter_name},
+                    ["UniqueIdentifier", MSVSNew.MakeGuid(source.name)],
+                ]
+            )
+            # Recurse and add its dependents.
+            _AppendFiltersForMSBuild(
+                filter_name,
+                source.contents,
+                rule_dependencies,
+                extension_to_rule_name,
+                platforms,
+                toolset,
+                filter_group,
+                source_group,
+            )
+        else:
+            # It's a source.  Create a source entry.
+            _, element = _MapFileToMsBuildSourceType(
+                source, rule_dependencies, extension_to_rule_name, platforms, toolset
+            )
+            source_entry = [element, {"Include": source}]
+            # Specify the filter it is part of, if any.
+            if parent_filter_name:
+                source_entry.append(["Filter", parent_filter_name])
+            source_group.append(source_entry)
+
+
+def _MapFileToMsBuildSourceType(
+    source, rule_dependencies, extension_to_rule_name, platforms, toolset
+):
+    """Returns the group and element type of the source file.
+
+  Arguments:
+      source: The source file name.
+      extension_to_rule_name: A dictionary mapping file extensions to rules.
+
+  Returns:
+      A pair of (group this file should be part of, the label of element)
+  """
+    _, ext = os.path.splitext(source)
+    ext = ext.lower()
+    if ext in extension_to_rule_name:
+        group = "rule"
+        element = extension_to_rule_name[ext]
+    elif ext in [".cc", ".cpp", ".c", ".cxx", ".mm"]:
+        group = "compile"
+        element = "ClCompile"
+    elif ext in [".h", ".hxx"]:
+        group = "include"
+        element = "ClInclude"
+    elif ext == ".rc":
+        group = "resource"
+        element = "ResourceCompile"
+    elif ext in [".s", ".asm"]:
+        group = "masm"
+        element = "MASM"
+        if "arm64" in platforms and toolset == "target":
+            element = "MARMASM"
+    elif ext == ".idl":
+        group = "midl"
+        element = "Midl"
+    elif source in rule_dependencies:
+        group = "rule_dependency"
+        element = "CustomBuild"
+    else:
+        group = "none"
+        element = "None"
+    return (group, element)
+
+
+def _GenerateRulesForMSBuild(
+    output_dir,
+    options,
+    spec,
+    sources,
+    excluded_sources,
+    props_files_of_rules,
+    targets_files_of_rules,
+    actions_to_add,
+    rule_dependencies,
+    extension_to_rule_name,
+):
+    # MSBuild rules are implemented using three files: an XML file, a .targets
+    # file and a .props file.
+    # For more details see:
+    # https://devblogs.microsoft.com/cppblog/quick-help-on-vs2010-custom-build-rule/
+    rules = spec.get("rules", [])
+    rules_native = [r for r in rules if not int(r.get("msvs_external_rule", 0))]
+    rules_external = [r for r in rules if int(r.get("msvs_external_rule", 0))]
+
+    msbuild_rules = []
+    for rule in rules_native:
+        # Skip a rule with no action and no inputs.
+        if "action" not in rule and not rule.get("rule_sources", []):
+            continue
+        msbuild_rule = MSBuildRule(rule, spec)
+        msbuild_rules.append(msbuild_rule)
+        rule_dependencies.update(msbuild_rule.additional_dependencies.split(";"))
+        extension_to_rule_name[msbuild_rule.extension] = msbuild_rule.rule_name
+    if msbuild_rules:
+        base = spec["target_name"] + options.suffix
+        props_name = base + ".props"
+        targets_name = base + ".targets"
+        xml_name = base + ".xml"
+
+        props_files_of_rules.add(props_name)
+        targets_files_of_rules.add(targets_name)
+
+        props_path = os.path.join(output_dir, props_name)
+        targets_path = os.path.join(output_dir, targets_name)
+        xml_path = os.path.join(output_dir, xml_name)
+
+        _GenerateMSBuildRulePropsFile(props_path, msbuild_rules)
+        _GenerateMSBuildRuleTargetsFile(targets_path, msbuild_rules)
+        _GenerateMSBuildRuleXmlFile(xml_path, msbuild_rules)
+
+    if rules_external:
+        _GenerateExternalRules(
+            rules_external, output_dir, spec, sources, options, actions_to_add
+        )
+    _AdjustSourcesForRules(rules, sources, excluded_sources, True)
+
+
+class MSBuildRule:
+    """Used to store information used to generate an MSBuild rule.
+
+  Attributes:
+    rule_name: The rule name, sanitized to use in XML.
+    target_name: The name of the target.
+    after_targets: The name of the AfterTargets element.
+    before_targets: The name of the BeforeTargets element.
+    depends_on: The name of the DependsOn element.
+    compute_output: The name of the ComputeOutput element.
+    dirs_to_make: The name of the DirsToMake element.
+    inputs: The name of the _inputs element.
+    tlog: The name of the _tlog element.
+    extension: The extension this rule applies to.
+    description: The message displayed when this rule is invoked.
+    additional_dependencies: A string listing additional dependencies.
+    outputs: The outputs of this rule.
+    command: The command used to run the rule.
+  """
+
+    def __init__(self, rule, spec):
+        self.display_name = rule["rule_name"]
+        # Assure that the rule name is only characters and numbers
+        self.rule_name = re.sub(r"\W", "_", self.display_name)
+        # Create the various element names, following the example set by the
+        # Visual Studio 2008 to 2010 conversion.  I don't know if VS2010
+        # is sensitive to the exact names.
+        self.target_name = "_" + self.rule_name
+        self.after_targets = self.rule_name + "AfterTargets"
+        self.before_targets = self.rule_name + "BeforeTargets"
+        self.depends_on = self.rule_name + "DependsOn"
+        self.compute_output = "Compute%sOutput" % self.rule_name
+        self.dirs_to_make = self.rule_name + "DirsToMake"
+        self.inputs = self.rule_name + "_inputs"
+        self.tlog = self.rule_name + "_tlog"
+        self.extension = rule["extension"]
+        if not self.extension.startswith("."):
+            self.extension = "." + self.extension
+
+        self.description = MSVSSettings.ConvertVCMacrosToMSBuild(
+            rule.get("message", self.rule_name)
+        )
+        old_additional_dependencies = _FixPaths(rule.get("inputs", []))
+        self.additional_dependencies = ";".join(
+            [
+                MSVSSettings.ConvertVCMacrosToMSBuild(i)
+                for i in old_additional_dependencies
+            ]
+        )
+        old_outputs = _FixPaths(rule.get("outputs", []))
+        self.outputs = ";".join(
+            [MSVSSettings.ConvertVCMacrosToMSBuild(i) for i in old_outputs]
+        )
+        old_command = _BuildCommandLineForRule(
+            spec, rule, has_input_path=True, do_setup_env=True
+        )
+        self.command = MSVSSettings.ConvertVCMacrosToMSBuild(old_command)
+
+
+def _GenerateMSBuildRulePropsFile(props_path, msbuild_rules):
+    """Generate the .props file."""
+    content = [
+        "Project",
+        {"xmlns": "http://schemas.microsoft.com/developer/msbuild/2003"},
+    ]
+    for rule in msbuild_rules:
+        content.extend(
+            [
+                [
+                    "PropertyGroup",
+                    {
+                        "Condition": "'$(%s)' == '' and '$(%s)' == '' and "
+                        "'$(ConfigurationType)' != 'Makefile'"
+                        % (rule.before_targets, rule.after_targets)
+                    },
+                    [rule.before_targets, "Midl"],
+                    [rule.after_targets, "CustomBuild"],
+                ],
+                [
+                    "PropertyGroup",
+                    [
+                        rule.depends_on,
+                        {"Condition": "'$(ConfigurationType)' != 'Makefile'"},
+                        "_SelectedFiles;$(%s)" % rule.depends_on,
+                    ],
+                ],
+                [
+                    "ItemDefinitionGroup",
+                    [
+                        rule.rule_name,
+                        ["CommandLineTemplate", rule.command],
+                        ["Outputs", rule.outputs],
+                        ["ExecutionDescription", rule.description],
+                        ["AdditionalDependencies", rule.additional_dependencies],
+                    ],
+                ],
+            ]
+        )
+    easy_xml.WriteXmlIfChanged(content, props_path, pretty=True, win32=True)
+
+
+def _GenerateMSBuildRuleTargetsFile(targets_path, msbuild_rules):
+    """Generate the .targets file."""
+    content = [
+        "Project",
+        {"xmlns": "http://schemas.microsoft.com/developer/msbuild/2003"},
+    ]
+    item_group = [
+        "ItemGroup",
+        [
+            "PropertyPageSchema",
+            {"Include": "$(MSBuildThisFileDirectory)$(MSBuildThisFileName).xml"},
+        ],
+    ]
+    for rule in msbuild_rules:
+        item_group.append(
+            [
+                "AvailableItemName",
+                {"Include": rule.rule_name},
+                ["Targets", rule.target_name],
+            ]
+        )
+    content.append(item_group)
+
+    for rule in msbuild_rules:
+        content.append(
+            [
+                "UsingTask",
+                {
+                    "TaskName": rule.rule_name,
+                    "TaskFactory": "XamlTaskFactory",
+                    "AssemblyName": "Microsoft.Build.Tasks.v4.0",
+                },
+                ["Task", "$(MSBuildThisFileDirectory)$(MSBuildThisFileName).xml"],
+            ]
+        )
+    for rule in msbuild_rules:
+        rule_name = rule.rule_name
+        target_outputs = "%%(%s.Outputs)" % rule_name
+        target_inputs = (
+            "%%(%s.Identity);%%(%s.AdditionalDependencies);" "$(MSBuildProjectFile)"
+        ) % (rule_name, rule_name)
+        rule_inputs = "%%(%s.Identity)" % rule_name
+        extension_condition = (
+            "'%(Extension)'=='.obj' or "
+            "'%(Extension)'=='.res' or "
+            "'%(Extension)'=='.rsc' or "
+            "'%(Extension)'=='.lib'"
+        )
+        remove_section = [
+            "ItemGroup",
+            {"Condition": "'@(SelectedFiles)' != ''"},
+            [
+                rule_name,
+                {
+                    "Remove": "@(%s)" % rule_name,
+                    "Condition": "'%(Identity)' != '@(SelectedFiles)'",
+                },
+            ],
+        ]
+        inputs_section = [
+            "ItemGroup",
+            [rule.inputs, {"Include": "%%(%s.AdditionalDependencies)" % rule_name}],
+        ]
+        logging_section = [
+            "ItemGroup",
+            [
+                rule.tlog,
+                {
+                    "Include": "%%(%s.Outputs)" % rule_name,
+                    "Condition": (
+                        "'%%(%s.Outputs)' != '' and "
+                        "'%%(%s.ExcludedFromBuild)' != 'true'" % (rule_name, rule_name)
+                    ),
+                },
+                ["Source", "@(%s, '|')" % rule_name],
+                ["Inputs", "@(%s -> '%%(Fullpath)', ';')" % rule.inputs],
+            ],
+        ]
+        message_section = [
+            "Message",
+            {"Importance": "High", "Text": "%%(%s.ExecutionDescription)" % rule_name},
+        ]
+        write_tlog_section = [
+            "WriteLinesToFile",
+            {
+                "Condition": "'@(%s)' != '' and '%%(%s.ExcludedFromBuild)' != "
+                "'true'" % (rule.tlog, rule.tlog),
+                "File": "$(IntDir)$(ProjectName).write.1.tlog",
+                "Lines": "^%%(%s.Source);@(%s->'%%(Fullpath)')"
+                % (rule.tlog, rule.tlog),
+            },
+        ]
+        read_tlog_section = [
+            "WriteLinesToFile",
+            {
+                "Condition": "'@(%s)' != '' and '%%(%s.ExcludedFromBuild)' != "
+                "'true'" % (rule.tlog, rule.tlog),
+                "File": "$(IntDir)$(ProjectName).read.1.tlog",
+                "Lines": f"^%({rule.tlog}.Source);%({rule.tlog}.Inputs)",
+            },
+        ]
+        command_and_input_section = [
+            rule_name,
+            {
+                "Condition": "'@(%s)' != '' and '%%(%s.ExcludedFromBuild)' != "
+                "'true'" % (rule_name, rule_name),
+                "EchoOff": "true",
+                "StandardOutputImportance": "High",
+                "StandardErrorImportance": "High",
+                "CommandLineTemplate": "%%(%s.CommandLineTemplate)" % rule_name,
+                "AdditionalOptions": "%%(%s.AdditionalOptions)" % rule_name,
+                "Inputs": rule_inputs,
+            },
+        ]
+        content.extend(
+            [
+                [
+                    "Target",
+                    {
+                        "Name": rule.target_name,
+                        "BeforeTargets": "$(%s)" % rule.before_targets,
+                        "AfterTargets": "$(%s)" % rule.after_targets,
+                        "Condition": "'@(%s)' != ''" % rule_name,
+                        "DependsOnTargets": "$(%s);%s"
+                        % (rule.depends_on, rule.compute_output),
+                        "Outputs": target_outputs,
+                        "Inputs": target_inputs,
+                    },
+                    remove_section,
+                    inputs_section,
+                    logging_section,
+                    message_section,
+                    write_tlog_section,
+                    read_tlog_section,
+                    command_and_input_section,
+                ],
+                [
+                    "PropertyGroup",
+                    [
+                        "ComputeLinkInputsTargets",
+                        "$(ComputeLinkInputsTargets);",
+                        "%s;" % rule.compute_output,
+                    ],
+                    [
+                        "ComputeLibInputsTargets",
+                        "$(ComputeLibInputsTargets);",
+                        "%s;" % rule.compute_output,
+                    ],
+                ],
+                [
+                    "Target",
+                    {
+                        "Name": rule.compute_output,
+                        "Condition": "'@(%s)' != ''" % rule_name,
+                    },
+                    [
+                        "ItemGroup",
+                        [
+                            rule.dirs_to_make,
+                            {
+                                "Condition": "'@(%s)' != '' and "
+                                "'%%(%s.ExcludedFromBuild)' != 'true'"
+                                % (rule_name, rule_name),
+                                "Include": "%%(%s.Outputs)" % rule_name,
+                            },
+                        ],
+                        [
+                            "Link",
+                            {
+                                "Include": "%%(%s.Identity)" % rule.dirs_to_make,
+                                "Condition": extension_condition,
+                            },
+                        ],
+                        [
+                            "Lib",
+                            {
+                                "Include": "%%(%s.Identity)" % rule.dirs_to_make,
+                                "Condition": extension_condition,
+                            },
+                        ],
+                        [
+                            "ImpLib",
+                            {
+                                "Include": "%%(%s.Identity)" % rule.dirs_to_make,
+                                "Condition": extension_condition,
+                            },
+                        ],
+                    ],
+                    [
+                        "MakeDir",
+                        {
+                            "Directories": (
+                                "@(%s->'%%(RootDir)%%(Directory)')" % rule.dirs_to_make
+                            )
+                        },
+                    ],
+                ],
+            ]
+        )
+    easy_xml.WriteXmlIfChanged(content, targets_path, pretty=True, win32=True)
+
+
+def _GenerateMSBuildRuleXmlFile(xml_path, msbuild_rules):
+    # Generate the .xml file
+    content = [
+        "ProjectSchemaDefinitions",
+        {
+            "xmlns": (
+                "clr-namespace:Microsoft.Build.Framework.XamlTypes;"
+                "assembly=Microsoft.Build.Framework"
+            ),
+            "xmlns:x": "http://schemas.microsoft.com/winfx/2006/xaml",
+            "xmlns:sys": "clr-namespace:System;assembly=mscorlib",
+            "xmlns:transformCallback": "Microsoft.Cpp.Dev10.ConvertPropertyCallback",
+        },
+    ]
+    for rule in msbuild_rules:
+        content.extend(
+            [
+                [
+                    "Rule",
+                    {
+                        "Name": rule.rule_name,
+                        "PageTemplate": "tool",
+                        "DisplayName": rule.display_name,
+                        "Order": "200",
+                    },
+                    [
+                        "Rule.DataSource",
+                        [
+                            "DataSource",
+                            {"Persistence": "ProjectFile", "ItemType": rule.rule_name},
+                        ],
+                    ],
+                    [
+                        "Rule.Categories",
+                        [
+                            "Category",
+                            {"Name": "General"},
+                            ["Category.DisplayName", ["sys:String", "General"]],
+                        ],
+                        [
+                            "Category",
+                            {"Name": "Command Line", "Subtype": "CommandLine"},
+                            ["Category.DisplayName", ["sys:String", "Command Line"]],
+                        ],
+                    ],
+                    [
+                        "StringListProperty",
+                        {
+                            "Name": "Inputs",
+                            "Category": "Command Line",
+                            "IsRequired": "true",
+                            "Switch": " ",
+                        },
+                        [
+                            "StringListProperty.DataSource",
+                            [
+                                "DataSource",
+                                {
+                                    "Persistence": "ProjectFile",
+                                    "ItemType": rule.rule_name,
+                                    "SourceType": "Item",
+                                },
+                            ],
+                        ],
+                    ],
+                    [
+                        "StringProperty",
+                        {
+                            "Name": "CommandLineTemplate",
+                            "DisplayName": "Command Line",
+                            "Visible": "False",
+                            "IncludeInCommandLine": "False",
+                        },
+                    ],
+                    [
+                        "DynamicEnumProperty",
+                        {
+                            "Name": rule.before_targets,
+                            "Category": "General",
+                            "EnumProvider": "Targets",
+                            "IncludeInCommandLine": "False",
+                        },
+                        [
+                            "DynamicEnumProperty.DisplayName",
+                            ["sys:String", "Execute Before"],
+                        ],
+                        [
+                            "DynamicEnumProperty.Description",
+                            [
+                                "sys:String",
+                                "Specifies the targets for the build customization"
+                                " to run before.",
+                            ],
+                        ],
+                        [
+                            "DynamicEnumProperty.ProviderSettings",
+                            [
+                                "NameValuePair",
+                                {
+                                    "Name": "Exclude",
+                                    "Value": "^%s|^Compute" % rule.before_targets,
+                                },
+                            ],
+                        ],
+                        [
+                            "DynamicEnumProperty.DataSource",
+                            [
+                                "DataSource",
+                                {
+                                    "Persistence": "ProjectFile",
+                                    "HasConfigurationCondition": "true",
+                                },
+                            ],
+                        ],
+                    ],
+                    [
+                        "DynamicEnumProperty",
+                        {
+                            "Name": rule.after_targets,
+                            "Category": "General",
+                            "EnumProvider": "Targets",
+                            "IncludeInCommandLine": "False",
+                        },
+                        [
+                            "DynamicEnumProperty.DisplayName",
+                            ["sys:String", "Execute After"],
+                        ],
+                        [
+                            "DynamicEnumProperty.Description",
+                            [
+                                "sys:String",
+                                (
+                                    "Specifies the targets for the build customization"
+                                    " to run after."
+                                ),
+                            ],
+                        ],
+                        [
+                            "DynamicEnumProperty.ProviderSettings",
+                            [
+                                "NameValuePair",
+                                {
+                                    "Name": "Exclude",
+                                    "Value": "^%s|^Compute" % rule.after_targets,
+                                },
+                            ],
+                        ],
+                        [
+                            "DynamicEnumProperty.DataSource",
+                            [
+                                "DataSource",
+                                {
+                                    "Persistence": "ProjectFile",
+                                    "ItemType": "",
+                                    "HasConfigurationCondition": "true",
+                                },
+                            ],
+                        ],
+                    ],
+                    [
+                        "StringListProperty",
+                        {
+                            "Name": "Outputs",
+                            "DisplayName": "Outputs",
+                            "Visible": "False",
+                            "IncludeInCommandLine": "False",
+                        },
+                    ],
+                    [
+                        "StringProperty",
+                        {
+                            "Name": "ExecutionDescription",
+                            "DisplayName": "Execution Description",
+                            "Visible": "False",
+                            "IncludeInCommandLine": "False",
+                        },
+                    ],
+                    [
+                        "StringListProperty",
+                        {
+                            "Name": "AdditionalDependencies",
+                            "DisplayName": "Additional Dependencies",
+                            "IncludeInCommandLine": "False",
+                            "Visible": "false",
+                        },
+                    ],
+                    [
+                        "StringProperty",
+                        {
+                            "Subtype": "AdditionalOptions",
+                            "Name": "AdditionalOptions",
+                            "Category": "Command Line",
+                        },
+                        [
+                            "StringProperty.DisplayName",
+                            ["sys:String", "Additional Options"],
+                        ],
+                        [
+                            "StringProperty.Description",
+                            ["sys:String", "Additional Options"],
+                        ],
+                    ],
+                ],
+                [
+                    "ItemType",
+                    {"Name": rule.rule_name, "DisplayName": rule.display_name},
+                ],
+                [
+                    "FileExtension",
+                    {"Name": "*" + rule.extension, "ContentType": rule.rule_name},
+                ],
+                [
+                    "ContentType",
+                    {
+                        "Name": rule.rule_name,
+                        "DisplayName": "",
+                        "ItemType": rule.rule_name,
+                    },
+                ],
+            ]
+        )
+    easy_xml.WriteXmlIfChanged(content, xml_path, pretty=True, win32=True)
+
+
+def _GetConfigurationAndPlatform(name, settings, spec):
+    configuration = name.rsplit("_", 1)[0]
+    platform = settings.get("msvs_configuration_platform", "Win32")
+    if spec["toolset"] == "host" and platform == "arm64":
+        platform = "x64"  # Host-only tools are always built for x64
+    return (configuration, platform)
+
+
+def _GetConfigurationCondition(name, settings, spec):
+    return r"'$(Configuration)|$(Platform)'=='%s|%s'" % _GetConfigurationAndPlatform(
+        name, settings, spec
+    )
+
+
+def _GetMSBuildProjectConfigurations(configurations, spec):
+    group = ["ItemGroup", {"Label": "ProjectConfigurations"}]
+    for (name, settings) in sorted(configurations.items()):
+        configuration, platform = _GetConfigurationAndPlatform(name, settings, spec)
+        designation = f"{configuration}|{platform}"
+        group.append(
+            [
+                "ProjectConfiguration",
+                {"Include": designation},
+                ["Configuration", configuration],
+                ["Platform", platform],
+            ]
+        )
+    return [group]
+
+
+def _GetMSBuildGlobalProperties(spec, version, guid, gyp_file_name):
+    namespace = os.path.splitext(gyp_file_name)[0]
+    properties = [
+        [
+            "PropertyGroup",
+            {"Label": "Globals"},
+            ["ProjectGuid", guid],
+            ["Keyword", "Win32Proj"],
+            ["RootNamespace", namespace],
+            ["IgnoreWarnCompileDuplicatedFilename", "true"],
+        ]
+    ]
+
+    if (
+        os.environ.get("PROCESSOR_ARCHITECTURE") == "AMD64"
+        or os.environ.get("PROCESSOR_ARCHITEW6432") == "AMD64"
+    ):
+        properties[0].append(["PreferredToolArchitecture", "x64"])
+
+    if spec.get("msvs_target_platform_version"):
+        target_platform_version = spec.get("msvs_target_platform_version")
+        properties[0].append(["WindowsTargetPlatformVersion", target_platform_version])
+        if spec.get("msvs_target_platform_minversion"):
+            target_platform_minversion = spec.get("msvs_target_platform_minversion")
+            properties[0].append(
+                ["WindowsTargetPlatformMinVersion", target_platform_minversion]
+            )
+        else:
+            properties[0].append(
+                ["WindowsTargetPlatformMinVersion", target_platform_version]
+            )
+
+    if spec.get("msvs_enable_winrt"):
+        properties[0].append(["DefaultLanguage", "en-US"])
+        properties[0].append(["AppContainerApplication", "true"])
+        if spec.get("msvs_application_type_revision"):
+            app_type_revision = spec.get("msvs_application_type_revision")
+            properties[0].append(["ApplicationTypeRevision", app_type_revision])
+        else:
+            properties[0].append(["ApplicationTypeRevision", "8.1"])
+        if spec.get("msvs_enable_winphone"):
+            properties[0].append(["ApplicationType", "Windows Phone"])
+        else:
+            properties[0].append(["ApplicationType", "Windows Store"])
+
+    platform_name = None
+    msvs_windows_sdk_version = None
+    for configuration in spec["configurations"].values():
+        platform_name = platform_name or _ConfigPlatform(configuration)
+        msvs_windows_sdk_version = (
+            msvs_windows_sdk_version
+            or _ConfigWindowsTargetPlatformVersion(configuration, version)
+        )
+        if platform_name and msvs_windows_sdk_version:
+            break
+    if msvs_windows_sdk_version:
+        properties[0].append(
+            ["WindowsTargetPlatformVersion", str(msvs_windows_sdk_version)]
+        )
+    elif version.compatible_sdks:
+        raise GypError(
+            "%s requires any SDK of %s version, but none were found"
+            % (version.description, version.compatible_sdks)
+        )
+
+    if platform_name == "ARM":
+        properties[0].append(["WindowsSDKDesktopARMSupport", "true"])
+
+    return properties
+
+
+def _GetMSBuildConfigurationDetails(spec, build_file):
+    properties = {}
+    for name, settings in spec["configurations"].items():
+        msbuild_attributes = _GetMSBuildAttributes(spec, settings, build_file)
+        condition = _GetConfigurationCondition(name, settings, spec)
+        character_set = msbuild_attributes.get("CharacterSet")
+        config_type = msbuild_attributes.get("ConfigurationType")
+        _AddConditionalProperty(properties, condition, "ConfigurationType", config_type)
+        if config_type == "Driver":
+            _AddConditionalProperty(properties, condition, "DriverType", "WDM")
+            _AddConditionalProperty(
+                properties, condition, "TargetVersion", _ConfigTargetVersion(settings)
+            )
+        if character_set:
+            if "msvs_enable_winrt" not in spec:
+                _AddConditionalProperty(
+                    properties, condition, "CharacterSet", character_set
+                )
+    return _GetMSBuildPropertyGroup(spec, "Configuration", properties)
+
+
+def _GetMSBuildLocalProperties(msbuild_toolset):
+    # Currently the only local property we support is PlatformToolset
+    properties = {}
+    if msbuild_toolset:
+        properties = [
+            [
+                "PropertyGroup",
+                {"Label": "Locals"},
+                ["PlatformToolset", msbuild_toolset],
+            ]
+        ]
+    return properties
+
+
+def _GetMSBuildPropertySheets(configurations, spec):
+    user_props = r"$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props"
+    additional_props = {}
+    props_specified = False
+    for name, settings in sorted(configurations.items()):
+        configuration = _GetConfigurationCondition(name, settings, spec)
+        if "msbuild_props" in settings:
+            additional_props[configuration] = _FixPaths(settings["msbuild_props"])
+            props_specified = True
+        else:
+            additional_props[configuration] = ""
+
+    if not props_specified:
+        return [
+            [
+                "ImportGroup",
+                {"Label": "PropertySheets"},
+                [
+                    "Import",
+                    {
+                        "Project": user_props,
+                        "Condition": "exists('%s')" % user_props,
+                        "Label": "LocalAppDataPlatform",
+                    },
+                ],
+            ]
+        ]
+    else:
+        sheets = []
+        for condition, props in additional_props.items():
+            import_group = [
+                "ImportGroup",
+                {"Label": "PropertySheets", "Condition": condition},
+                [
+                    "Import",
+                    {
+                        "Project": user_props,
+                        "Condition": "exists('%s')" % user_props,
+                        "Label": "LocalAppDataPlatform",
+                    },
+                ],
+            ]
+            for props_file in props:
+                import_group.append(["Import", {"Project": props_file}])
+            sheets.append(import_group)
+        return sheets
+
+
+def _ConvertMSVSBuildAttributes(spec, config, build_file):
+    config_type = _GetMSVSConfigurationType(spec, build_file)
+    msvs_attributes = _GetMSVSAttributes(spec, config, config_type)
+    msbuild_attributes = {}
+    for a in msvs_attributes:
+        if a in ["IntermediateDirectory", "OutputDirectory"]:
+            directory = MSVSSettings.ConvertVCMacrosToMSBuild(msvs_attributes[a])
+            if not directory.endswith("\\"):
+                directory += "\\"
+            msbuild_attributes[a] = directory
+        elif a == "CharacterSet":
+            msbuild_attributes[a] = _ConvertMSVSCharacterSet(msvs_attributes[a])
+        elif a == "ConfigurationType":
+            msbuild_attributes[a] = _ConvertMSVSConfigurationType(msvs_attributes[a])
+        else:
+            print("Warning: Do not know how to convert MSVS attribute " + a)
+    return msbuild_attributes
+
+
+def _ConvertMSVSCharacterSet(char_set):
+    if char_set.isdigit():
+        char_set = {"0": "MultiByte", "1": "Unicode", "2": "MultiByte"}[char_set]
+    return char_set
+
+
+def _ConvertMSVSConfigurationType(config_type):
+    if config_type.isdigit():
+        config_type = {
+            "1": "Application",
+            "2": "DynamicLibrary",
+            "4": "StaticLibrary",
+            "5": "Driver",
+            "10": "Utility",
+        }[config_type]
+    return config_type
+
+
+def _GetMSBuildAttributes(spec, config, build_file):
+    if "msbuild_configuration_attributes" not in config:
+        msbuild_attributes = _ConvertMSVSBuildAttributes(spec, config, build_file)
+
+    else:
+        config_type = _GetMSVSConfigurationType(spec, build_file)
+        config_type = _ConvertMSVSConfigurationType(config_type)
+        msbuild_attributes = config.get("msbuild_configuration_attributes", {})
+        msbuild_attributes.setdefault("ConfigurationType", config_type)
+        output_dir = msbuild_attributes.get(
+            "OutputDirectory", "$(SolutionDir)$(Configuration)"
+        )
+        msbuild_attributes["OutputDirectory"] = _FixPath(output_dir) + "\\"
+        if "IntermediateDirectory" not in msbuild_attributes:
+            intermediate = _FixPath("$(Configuration)") + "\\"
+            msbuild_attributes["IntermediateDirectory"] = intermediate
+        if "CharacterSet" in msbuild_attributes:
+            msbuild_attributes["CharacterSet"] = _ConvertMSVSCharacterSet(
+                msbuild_attributes["CharacterSet"]
+            )
+    if "TargetName" not in msbuild_attributes:
+        prefix = spec.get("product_prefix", "")
+        product_name = spec.get("product_name", "$(ProjectName)")
+        target_name = prefix + product_name
+        msbuild_attributes["TargetName"] = target_name
+    if "TargetExt" not in msbuild_attributes and "product_extension" in spec:
+        ext = spec.get("product_extension")
+        msbuild_attributes["TargetExt"] = "." + ext
+
+    if spec.get("msvs_external_builder"):
+        external_out_dir = spec.get("msvs_external_builder_out_dir", ".")
+        msbuild_attributes["OutputDirectory"] = _FixPath(external_out_dir) + "\\"
+
+    # Make sure that 'TargetPath' matches 'Lib.OutputFile' or 'Link.OutputFile'
+    # (depending on the tool used) to avoid MSB8012 warning.
+    msbuild_tool_map = {
+        "executable": "Link",
+        "shared_library": "Link",
+        "loadable_module": "Link",
+        "windows_driver": "Link",
+        "static_library": "Lib",
+    }
+    msbuild_tool = msbuild_tool_map.get(spec["type"])
+    if msbuild_tool:
+        msbuild_settings = config["finalized_msbuild_settings"]
+        out_file = msbuild_settings[msbuild_tool].get("OutputFile")
+        if out_file:
+            msbuild_attributes["TargetPath"] = _FixPath(out_file)
+        target_ext = msbuild_settings[msbuild_tool].get("TargetExt")
+        if target_ext:
+            msbuild_attributes["TargetExt"] = target_ext
+
+    return msbuild_attributes
+
+
+def _GetMSBuildConfigurationGlobalProperties(spec, configurations, build_file):
+    # TODO(jeanluc) We could optimize out the following and do it only if
+    # there are actions.
+    # TODO(jeanluc) Handle the equivalent of setting 'CYGWIN=nontsec'.
+    new_paths = []
+    cygwin_dirs = spec.get("msvs_cygwin_dirs", ["."])[0]
+    if cygwin_dirs:
+        cyg_path = "$(MSBuildProjectDirectory)\\%s\\bin\\" % _FixPath(cygwin_dirs)
+        new_paths.append(cyg_path)
+        # TODO(jeanluc) Change the convention to have both a cygwin_dir and a
+        # python_dir.
+        python_path = cyg_path.replace("cygwin\\bin", "python_26")
+        new_paths.append(python_path)
+        if new_paths:
+            new_paths = "$(ExecutablePath);" + ";".join(new_paths)
+
+    properties = {}
+    for (name, configuration) in sorted(configurations.items()):
+        condition = _GetConfigurationCondition(name, configuration, spec)
+        attributes = _GetMSBuildAttributes(spec, configuration, build_file)
+        msbuild_settings = configuration["finalized_msbuild_settings"]
+        _AddConditionalProperty(
+            properties, condition, "IntDir", attributes["IntermediateDirectory"]
+        )
+        _AddConditionalProperty(
+            properties, condition, "OutDir", attributes["OutputDirectory"]
+        )
+        _AddConditionalProperty(
+            properties, condition, "TargetName", attributes["TargetName"]
+        )
+        if "TargetExt" in attributes:
+            _AddConditionalProperty(
+                properties, condition, "TargetExt", attributes["TargetExt"]
+            )
+
+        if attributes.get("TargetPath"):
+            _AddConditionalProperty(
+                properties, condition, "TargetPath", attributes["TargetPath"]
+            )
+        if attributes.get("TargetExt"):
+            _AddConditionalProperty(
+                properties, condition, "TargetExt", attributes["TargetExt"]
+            )
+
+        if new_paths:
+            _AddConditionalProperty(properties, condition, "ExecutablePath", new_paths)
+        tool_settings = msbuild_settings.get("", {})
+        for name, value in sorted(tool_settings.items()):
+            formatted_value = _GetValueFormattedForMSBuild("", name, value)
+            _AddConditionalProperty(properties, condition, name, formatted_value)
+    return _GetMSBuildPropertyGroup(spec, None, properties)
+
+
+def _AddConditionalProperty(properties, condition, name, value):
+    """Adds a property / conditional value pair to a dictionary.
+
+  Arguments:
+    properties: The dictionary to be modified.  The key is the name of the
+        property.  The value is itself a dictionary; its key is the value and
+        the value a list of condition for which this value is true.
+    condition: The condition under which the named property has the value.
+    name: The name of the property.
+    value: The value of the property.
+  """
+    if name not in properties:
+        properties[name] = {}
+    values = properties[name]
+    if value not in values:
+        values[value] = []
+    conditions = values[value]
+    conditions.append(condition)
+
+
+# Regex for msvs variable references ( i.e. $(FOO) ).
+MSVS_VARIABLE_REFERENCE = re.compile(r"\$$([a-zA-Z_][a-zA-Z0-9_]*)$")
+
+
+def _GetMSBuildPropertyGroup(spec, label, properties):
+    """Returns a PropertyGroup definition for the specified properties.
+
+  Arguments:
+    spec: The target project dict.
+    label: An optional label for the PropertyGroup.
+    properties: The dictionary to be converted.  The key is the name of the
+        property.  The value is itself a dictionary; its key is the value and
+        the value a list of condition for which this value is true.
+  """
+    group = ["PropertyGroup"]
+    if label:
+        group.append({"Label": label})
+    num_configurations = len(spec["configurations"])
+
+    def GetEdges(node):
+        # Use a definition of edges such that user_of_variable -> used_varible.
+        # This happens to be easier in this case, since a variable's
+        # definition contains all variables it references in a single string.
+        edges = set()
+        for value in sorted(properties[node].keys()):
+            # Add to edges all $(...) references to variables.
+            #
+            # Variable references that refer to names not in properties are excluded
+            # These can exist for instance to refer built in definitions like
+            # $(SolutionDir).
+            #
+            # Self references are ignored. Self reference is used in a few places to
+            # append to the default value. I.e. PATH=$(PATH);other_path
+            edges.update(
+                {
+                    v
+                    for v in MSVS_VARIABLE_REFERENCE.findall(value)
+                    if v in properties and v != node
+                }
+            )
+        return edges
+
+    properties_ordered = gyp.common.TopologicallySorted(properties.keys(), GetEdges)
+    # Walk properties in the reverse of a topological sort on
+    # user_of_variable -> used_variable as this ensures variables are
+    # defined before they are used.
+    # NOTE: reverse(topsort(DAG)) = topsort(reverse_edges(DAG))
+    for name in reversed(properties_ordered):
+        values = properties[name]
+        for value, conditions in sorted(values.items()):
+            if len(conditions) == num_configurations:
+                # If the value is the same all configurations,
+                # just add one unconditional entry.
+                group.append([name, value])
+            else:
+                for condition in conditions:
+                    group.append([name, {"Condition": condition}, value])
+    return [group]
+
+
+def _GetMSBuildToolSettingsSections(spec, configurations):
+    groups = []
+    for (name, configuration) in sorted(configurations.items()):
+        msbuild_settings = configuration["finalized_msbuild_settings"]
+        group = [
+            "ItemDefinitionGroup",
+            {"Condition": _GetConfigurationCondition(name, configuration, spec)},
+        ]
+        for tool_name, tool_settings in sorted(msbuild_settings.items()):
+            # Skip the tool named '' which is a holder of global settings handled
+            # by _GetMSBuildConfigurationGlobalProperties.
+            if tool_name:
+                if tool_settings:
+                    tool = [tool_name]
+                    for name, value in sorted(tool_settings.items()):
+                        formatted_value = _GetValueFormattedForMSBuild(
+                            tool_name, name, value
+                        )
+                        tool.append([name, formatted_value])
+                    group.append(tool)
+        groups.append(group)
+    return groups
+
+
+def _FinalizeMSBuildSettings(spec, configuration):
+    if "msbuild_settings" in configuration:
+        converted = False
+        msbuild_settings = configuration["msbuild_settings"]
+        MSVSSettings.ValidateMSBuildSettings(msbuild_settings)
+    else:
+        converted = True
+        msvs_settings = configuration.get("msvs_settings", {})
+        msbuild_settings = MSVSSettings.ConvertToMSBuildSettings(msvs_settings)
+    include_dirs, midl_include_dirs, resource_include_dirs = _GetIncludeDirs(
+        configuration
+    )
+    libraries = _GetLibraries(spec)
+    library_dirs = _GetLibraryDirs(configuration)
+    out_file, _, msbuild_tool = _GetOutputFilePathAndTool(spec, msbuild=True)
+    target_ext = _GetOutputTargetExt(spec)
+    defines = _GetDefines(configuration)
+    if converted:
+        # Visual Studio 2010 has TR1
+        defines = [d for d in defines if d != "_HAS_TR1=0"]
+        # Warn of ignored settings
+        ignored_settings = ["msvs_tool_files"]
+        for ignored_setting in ignored_settings:
+            value = configuration.get(ignored_setting)
+            if value:
+                print(
+                    "Warning: The automatic conversion to MSBuild does not handle "
+                    "%s.  Ignoring setting of %s" % (ignored_setting, str(value))
+                )
+
+    defines = [_EscapeCppDefineForMSBuild(d) for d in defines]
+    disabled_warnings = _GetDisabledWarnings(configuration)
+    prebuild = configuration.get("msvs_prebuild")
+    postbuild = configuration.get("msvs_postbuild")
+    def_file = _GetModuleDefinition(spec)
+    precompiled_header = configuration.get("msvs_precompiled_header")
+
+    # Add the information to the appropriate tool
+    # TODO(jeanluc) We could optimize and generate these settings only if
+    # the corresponding files are found, e.g. don't generate ResourceCompile
+    # if you don't have any resources.
+    _ToolAppend(
+        msbuild_settings, "ClCompile", "AdditionalIncludeDirectories", include_dirs
+    )
+    _ToolAppend(
+        msbuild_settings, "Midl", "AdditionalIncludeDirectories", midl_include_dirs
+    )
+    _ToolAppend(
+        msbuild_settings,
+        "ResourceCompile",
+        "AdditionalIncludeDirectories",
+        resource_include_dirs,
+    )
+    # Add in libraries, note that even for empty libraries, we want this
+    # set, to prevent inheriting default libraries from the environment.
+    _ToolSetOrAppend(msbuild_settings, "Link", "AdditionalDependencies", libraries)
+    _ToolAppend(msbuild_settings, "Link", "AdditionalLibraryDirectories", library_dirs)
+    if out_file:
+        _ToolAppend(
+            msbuild_settings, msbuild_tool, "OutputFile", out_file, only_if_unset=True
+        )
+    if target_ext:
+        _ToolAppend(
+            msbuild_settings, msbuild_tool, "TargetExt", target_ext, only_if_unset=True
+        )
+    # Add defines.
+    _ToolAppend(msbuild_settings, "ClCompile", "PreprocessorDefinitions", defines)
+    _ToolAppend(msbuild_settings, "ResourceCompile", "PreprocessorDefinitions", defines)
+    # Add disabled warnings.
+    _ToolAppend(
+        msbuild_settings, "ClCompile", "DisableSpecificWarnings", disabled_warnings
+    )
+    # Turn on precompiled headers if appropriate.
+    if precompiled_header:
+        precompiled_header = os.path.split(precompiled_header)[1]
+        _ToolAppend(msbuild_settings, "ClCompile", "PrecompiledHeader", "Use")
+        _ToolAppend(
+            msbuild_settings, "ClCompile", "PrecompiledHeaderFile", precompiled_header
+        )
+        _ToolAppend(
+            msbuild_settings, "ClCompile", "ForcedIncludeFiles", [precompiled_header]
+        )
+    else:
+        _ToolAppend(msbuild_settings, "ClCompile", "PrecompiledHeader", "NotUsing")
+    # Turn off WinRT compilation
+    _ToolAppend(msbuild_settings, "ClCompile", "CompileAsWinRT", "false")
+    # Turn on import libraries if appropriate
+    if spec.get("msvs_requires_importlibrary"):
+        _ToolAppend(msbuild_settings, "", "IgnoreImportLibrary", "false")
+    # Loadable modules don't generate import libraries;
+    # tell dependent projects to not expect one.
+    if spec["type"] == "loadable_module":
+        _ToolAppend(msbuild_settings, "", "IgnoreImportLibrary", "true")
+    # Set the module definition file if any.
+    if def_file:
+        _ToolAppend(msbuild_settings, "Link", "ModuleDefinitionFile", def_file)
+    configuration["finalized_msbuild_settings"] = msbuild_settings
+    if prebuild:
+        _ToolAppend(msbuild_settings, "PreBuildEvent", "Command", prebuild)
+    if postbuild:
+        _ToolAppend(msbuild_settings, "PostBuildEvent", "Command", postbuild)
+
+
+def _GetValueFormattedForMSBuild(tool_name, name, value):
+    if type(value) == list:
+        # For some settings, VS2010 does not automatically extends the settings
+        # TODO(jeanluc) Is this what we want?
+        if name in [
+            "AdditionalIncludeDirectories",
+            "AdditionalLibraryDirectories",
+            "AdditionalOptions",
+            "DelayLoadDLLs",
+            "DisableSpecificWarnings",
+            "PreprocessorDefinitions",
+        ]:
+            value.append("%%(%s)" % name)
+        # For most tools, entries in a list should be separated with ';' but some
+        # settings use a space.  Check for those first.
+        exceptions = {
+            "ClCompile": ["AdditionalOptions"],
+            "Link": ["AdditionalOptions"],
+            "Lib": ["AdditionalOptions"],
+        }
+        if tool_name in exceptions and name in exceptions[tool_name]:
+            char = " "
+        else:
+            char = ";"
+        formatted_value = char.join(
+            [MSVSSettings.ConvertVCMacrosToMSBuild(i) for i in value]
+        )
+    else:
+        formatted_value = MSVSSettings.ConvertVCMacrosToMSBuild(value)
+    return formatted_value
+
+
+def _VerifySourcesExist(sources, root_dir):
+    """Verifies that all source files exist on disk.
+
+  Checks that all regular source files, i.e. not created at run time,
+  exist on disk.  Missing files cause needless recompilation but no otherwise
+  visible errors.
+
+  Arguments:
+    sources: A recursive list of Filter/file names.
+    root_dir: The root directory for the relative path names.
+  Returns:
+    A list of source files that cannot be found on disk.
+  """
+    missing_sources = []
+    for source in sources:
+        if isinstance(source, MSVSProject.Filter):
+            missing_sources.extend(_VerifySourcesExist(source.contents, root_dir))
+        else:
+            if "$" not in source:
+                full_path = os.path.join(root_dir, source)
+                if not os.path.exists(full_path):
+                    missing_sources.append(full_path)
+    return missing_sources
+
+
+def _GetMSBuildSources(
+    spec,
+    sources,
+    exclusions,
+    rule_dependencies,
+    extension_to_rule_name,
+    actions_spec,
+    sources_handled_by_action,
+    list_excluded,
+):
+    groups = [
+        "none",
+        "masm",
+        "midl",
+        "include",
+        "compile",
+        "resource",
+        "rule",
+        "rule_dependency",
+    ]
+    grouped_sources = {}
+    for g in groups:
+        grouped_sources[g] = []
+
+    _AddSources2(
+        spec,
+        sources,
+        exclusions,
+        grouped_sources,
+        rule_dependencies,
+        extension_to_rule_name,
+        sources_handled_by_action,
+        list_excluded,
+    )
+    sources = []
+    for g in groups:
+        if grouped_sources[g]:
+            sources.append(["ItemGroup"] + grouped_sources[g])
+    if actions_spec:
+        sources.append(["ItemGroup"] + actions_spec)
+    return sources
+
+
+def _AddSources2(
+    spec,
+    sources,
+    exclusions,
+    grouped_sources,
+    rule_dependencies,
+    extension_to_rule_name,
+    sources_handled_by_action,
+    list_excluded,
+):
+    extensions_excluded_from_precompile = []
+    for source in sources:
+        if isinstance(source, MSVSProject.Filter):
+            _AddSources2(
+                spec,
+                source.contents,
+                exclusions,
+                grouped_sources,
+                rule_dependencies,
+                extension_to_rule_name,
+                sources_handled_by_action,
+                list_excluded,
+            )
+        else:
+            if source not in sources_handled_by_action:
+                detail = []
+                excluded_configurations = exclusions.get(source, [])
+                if len(excluded_configurations) == len(spec["configurations"]):
+                    detail.append(["ExcludedFromBuild", "true"])
+                else:
+                    for config_name, configuration in sorted(excluded_configurations):
+                        condition = _GetConfigurationCondition(
+                            config_name, configuration
+                        )
+                        detail.append(
+                            ["ExcludedFromBuild", {"Condition": condition}, "true"]
+                        )
+                # Add precompile if needed
+                for config_name, configuration in spec["configurations"].items():
+                    precompiled_source = configuration.get(
+                        "msvs_precompiled_source", ""
+                    )
+                    if precompiled_source != "":
+                        precompiled_source = _FixPath(precompiled_source)
+                        if not extensions_excluded_from_precompile:
+                            # If the precompiled header is generated by a C source,
+                            # we must not try to use it for C++ sources,
+                            # and vice versa.
+                            basename, extension = os.path.splitext(precompiled_source)
+                            if extension == ".c":
+                                extensions_excluded_from_precompile = [
+                                    ".cc",
+                                    ".cpp",
+                                    ".cxx",
+                                ]
+                            else:
+                                extensions_excluded_from_precompile = [".c"]
+
+                    if precompiled_source == source:
+                        condition = _GetConfigurationCondition(
+                            config_name, configuration, spec
+                        )
+                        detail.append(
+                            ["PrecompiledHeader", {"Condition": condition}, "Create"]
+                        )
+                    else:
+                        # Turn off precompiled header usage for source files of a
+                        # different type than the file that generated the
+                        # precompiled header.
+                        for extension in extensions_excluded_from_precompile:
+                            if source.endswith(extension):
+                                detail.append(["PrecompiledHeader", ""])
+                                detail.append(["ForcedIncludeFiles", ""])
+
+                group, element = _MapFileToMsBuildSourceType(
+                    source,
+                    rule_dependencies,
+                    extension_to_rule_name,
+                    _GetUniquePlatforms(spec),
+                    spec["toolset"],
+                )
+                if group == "compile" and not os.path.isabs(source):
+                    # Add an <ObjectFileName> value to support duplicate source
+                    # file basenames, except for absolute paths to avoid paths
+                    # with more than 260 characters.
+                    file_name = os.path.splitext(source)[0] + ".obj"
+                    if file_name.startswith("..\\"):
+                        file_name = re.sub(r"^(\.\.\\)+", "", file_name)
+                    elif file_name.startswith("$("):
+                        file_name = re.sub(r"^\$$[^)]+$\\", "", file_name)
+                    detail.append(["ObjectFileName", "$(IntDir)\\" + file_name])
+                grouped_sources[group].append([element, {"Include": source}] + detail)
+
+
+def _GetMSBuildProjectReferences(project):
+    references = []
+    if project.dependencies:
+        group = ["ItemGroup"]
+        added_dependency_set = set()
+        for dependency in project.dependencies:
+            dependency_spec = dependency.spec
+            should_skip_dep = False
+            if project.spec["toolset"] == "target":
+                if dependency_spec["toolset"] == "host":
+                    if dependency_spec["type"] == "static_library":
+                        should_skip_dep = True
+            if dependency.name.startswith("run_"):
+                should_skip_dep = False
+            if should_skip_dep:
+                continue
+
+            canonical_name = dependency.name.replace("_host", "")
+            added_dependency_set.add(canonical_name)
+            guid = dependency.guid
+            project_dir = os.path.split(project.path)[0]
+            relative_path = gyp.common.RelativePath(dependency.path, project_dir)
+            project_ref = [
+                "ProjectReference",
+                {"Include": relative_path},
+                ["Project", guid],
+                ["ReferenceOutputAssembly", "false"],
+            ]
+            for config in dependency.spec.get("configurations", {}).values():
+                if config.get("msvs_use_library_dependency_inputs", 0):
+                    project_ref.append(["UseLibraryDependencyInputs", "true"])
+                    break
+                # If it's disabled in any config, turn it off in the reference.
+                if config.get("msvs_2010_disable_uldi_when_referenced", 0):
+                    project_ref.append(["UseLibraryDependencyInputs", "false"])
+                    break
+            group.append(project_ref)
+        references.append(group)
+    return references
+
+
+def _GenerateMSBuildProject(project, options, version, generator_flags, spec):
+    spec = project.spec
+    configurations = spec["configurations"]
+    toolset = spec["toolset"]
+    project_dir, project_file_name = os.path.split(project.path)
+    gyp.common.EnsureDirExists(project.path)
+    # Prepare list of sources and excluded sources.
+
+    gyp_file = os.path.split(project.build_file)[1]
+    sources, excluded_sources = _PrepareListOfSources(spec, generator_flags, gyp_file)
+    # Add rules.
+    actions_to_add = {}
+    props_files_of_rules = set()
+    targets_files_of_rules = set()
+    rule_dependencies = set()
+    extension_to_rule_name = {}
+    list_excluded = generator_flags.get("msvs_list_excluded_files", True)
+    platforms = _GetUniquePlatforms(spec)
+
+    # Don't generate rules if we are using an external builder like ninja.
+    if not spec.get("msvs_external_builder"):
+        _GenerateRulesForMSBuild(
+            project_dir,
+            options,
+            spec,
+            sources,
+            excluded_sources,
+            props_files_of_rules,
+            targets_files_of_rules,
+            actions_to_add,
+            rule_dependencies,
+            extension_to_rule_name,
+        )
+    else:
+        rules = spec.get("rules", [])
+        _AdjustSourcesForRules(rules, sources, excluded_sources, True)
+
+    sources, excluded_sources, excluded_idl = _AdjustSourcesAndConvertToFilterHierarchy(
+        spec, options, project_dir, sources, excluded_sources, list_excluded, version
+    )
+
+    # Don't add actions if we are using an external builder like ninja.
+    if not spec.get("msvs_external_builder"):
+        _AddActions(actions_to_add, spec, project.build_file)
+        _AddCopies(actions_to_add, spec)
+
+        # NOTE: this stanza must appear after all actions have been decided.
+        # Don't excluded sources with actions attached, or they won't run.
+        excluded_sources = _FilterActionsFromExcluded(excluded_sources, actions_to_add)
+
+    exclusions = _GetExcludedFilesFromBuild(spec, excluded_sources, excluded_idl)
+    actions_spec, sources_handled_by_action = _GenerateActionsForMSBuild(
+        spec, actions_to_add
+    )
+
+    _GenerateMSBuildFiltersFile(
+        project.path + ".filters",
+        sources,
+        rule_dependencies,
+        extension_to_rule_name,
+        platforms,
+        toolset,
+    )
+    missing_sources = _VerifySourcesExist(sources, project_dir)
+
+    for configuration in configurations.values():
+        _FinalizeMSBuildSettings(spec, configuration)
+
+    # Add attributes to root element
+
+    import_default_section = [
+        ["Import", {"Project": r"$(VCTargetsPath)\Microsoft.Cpp.Default.props"}]
+    ]
+    import_cpp_props_section = [
+        ["Import", {"Project": r"$(VCTargetsPath)\Microsoft.Cpp.props"}]
+    ]
+    import_cpp_targets_section = [
+        ["Import", {"Project": r"$(VCTargetsPath)\Microsoft.Cpp.targets"}]
+    ]
+    import_masm_props_section = [
+        ["Import", {"Project": r"$(VCTargetsPath)\BuildCustomizations\masm.props"}]
+    ]
+    import_masm_targets_section = [
+        ["Import", {"Project": r"$(VCTargetsPath)\BuildCustomizations\masm.targets"}]
+    ]
+    import_marmasm_props_section = [
+        ["Import", {"Project": r"$(VCTargetsPath)\BuildCustomizations\marmasm.props"}]
+    ]
+    import_marmasm_targets_section = [
+        ["Import", {"Project": r"$(VCTargetsPath)\BuildCustomizations\marmasm.targets"}]
+    ]
+    macro_section = [["PropertyGroup", {"Label": "UserMacros"}]]
+
+    content = [
+        "Project",
+        {
+            "xmlns": "http://schemas.microsoft.com/developer/msbuild/2003",
+            "ToolsVersion": version.ProjectVersion(),
+            "DefaultTargets": "Build",
+        },
+    ]
+
+    content += _GetMSBuildProjectConfigurations(configurations, spec)
+    content += _GetMSBuildGlobalProperties(
+        spec, version, project.guid, project_file_name
+    )
+    content += import_default_section
+    content += _GetMSBuildConfigurationDetails(spec, project.build_file)
+    if spec.get("msvs_enable_winphone"):
+        content += _GetMSBuildLocalProperties("v120_wp81")
+    else:
+        content += _GetMSBuildLocalProperties(project.msbuild_toolset)
+    content += import_cpp_props_section
+    content += import_masm_props_section
+    if "arm64" in platforms and toolset == "target":
+        content += import_marmasm_props_section
+    content += _GetMSBuildExtensions(props_files_of_rules)
+    content += _GetMSBuildPropertySheets(configurations, spec)
+    content += macro_section
+    content += _GetMSBuildConfigurationGlobalProperties(
+        spec, configurations, project.build_file
+    )
+    content += _GetMSBuildToolSettingsSections(spec, configurations)
+    content += _GetMSBuildSources(
+        spec,
+        sources,
+        exclusions,
+        rule_dependencies,
+        extension_to_rule_name,
+        actions_spec,
+        sources_handled_by_action,
+        list_excluded,
+    )
+    content += _GetMSBuildProjectReferences(project)
+    content += import_cpp_targets_section
+    content += import_masm_targets_section
+    if "arm64" in platforms and toolset == "target":
+        content += import_marmasm_targets_section
+    content += _GetMSBuildExtensionTargets(targets_files_of_rules)
+
+    if spec.get("msvs_external_builder"):
+        content += _GetMSBuildExternalBuilderTargets(spec)
+
+    # TODO(jeanluc) File a bug to get rid of runas.  We had in MSVS:
+    # has_run_as = _WriteMSVSUserFile(project.path, version, spec)
+
+    easy_xml.WriteXmlIfChanged(content, project.path, pretty=True, win32=True)
+
+    return missing_sources
+
+
+def _GetMSBuildExternalBuilderTargets(spec):
+    """Return a list of MSBuild targets for external builders.
+
+  The "Build" and "Clean" targets are always generated.  If the spec contains
+  'msvs_external_builder_clcompile_cmd', then the "ClCompile" target will also
+  be generated, to support building selected C/C++ files.
+
+  Arguments:
+    spec: The gyp target spec.
+  Returns:
+    List of MSBuild 'Target' specs.
+  """
+    build_cmd = _BuildCommandLineForRuleRaw(
+        spec, spec["msvs_external_builder_build_cmd"], False, False, False, False
+    )
+    build_target = ["Target", {"Name": "Build"}]
+    build_target.append(["Exec", {"Command": build_cmd}])
+
+    clean_cmd = _BuildCommandLineForRuleRaw(
+        spec, spec["msvs_external_builder_clean_cmd"], False, False, False, False
+    )
+    clean_target = ["Target", {"Name": "Clean"}]
+    clean_target.append(["Exec", {"Command": clean_cmd}])
+
+    targets = [build_target, clean_target]
+
+    if spec.get("msvs_external_builder_clcompile_cmd"):
+        clcompile_cmd = _BuildCommandLineForRuleRaw(
+            spec,
+            spec["msvs_external_builder_clcompile_cmd"],
+            False,
+            False,
+            False,
+            False,
+        )
+        clcompile_target = ["Target", {"Name": "ClCompile"}]
+        clcompile_target.append(["Exec", {"Command": clcompile_cmd}])
+        targets.append(clcompile_target)
+
+    return targets
+
+
+def _GetMSBuildExtensions(props_files_of_rules):
+    extensions = ["ImportGroup", {"Label": "ExtensionSettings"}]
+    for props_file in props_files_of_rules:
+        extensions.append(["Import", {"Project": props_file}])
+    return [extensions]
+
+
+def _GetMSBuildExtensionTargets(targets_files_of_rules):
+    targets_node = ["ImportGroup", {"Label": "ExtensionTargets"}]
+    for targets_file in sorted(targets_files_of_rules):
+        targets_node.append(["Import", {"Project": targets_file}])
+    return [targets_node]
+
+
+def _GenerateActionsForMSBuild(spec, actions_to_add):
+    """Add actions accumulated into an actions_to_add, merging as needed.
+
+  Arguments:
+    spec: the target project dict
+    actions_to_add: dictionary keyed on input name, which maps to a list of
+        dicts describing the actions attached to that input file.
+
+  Returns:
+    A pair of (action specification, the sources handled by this action).
+  """
+    sources_handled_by_action = OrderedSet()
+    actions_spec = []
+    for primary_input, actions in actions_to_add.items():
+        if generator_supports_multiple_toolsets:
+            primary_input = primary_input.replace(".exe", "_host.exe")
+        inputs = OrderedSet()
+        outputs = OrderedSet()
+        descriptions = []
+        commands = []
+        for action in actions:
+
+            def fixup_host_exe(i):
+                if "$(OutDir)" in i:
+                    i = i.replace(".exe", "_host.exe")
+                return i
+
+            if generator_supports_multiple_toolsets:
+                action["inputs"] = [fixup_host_exe(i) for i in action["inputs"]]
+            inputs.update(OrderedSet(action["inputs"]))
+            outputs.update(OrderedSet(action["outputs"]))
+            descriptions.append(action["description"])
+            cmd = action["command"]
+            if generator_supports_multiple_toolsets:
+                cmd = cmd.replace(".exe", "_host.exe")
+            # For most actions, add 'call' so that actions that invoke batch files
+            # return and continue executing.  msbuild_use_call provides a way to
+            # disable this but I have not seen any adverse effect from doing that
+            # for everything.
+            if action.get("msbuild_use_call", True):
+                cmd = "call " + cmd
+            commands.append(cmd)
+        # Add the custom build action for one input file.
+        description = ", and also ".join(descriptions)
+
+        # We can't join the commands simply with && because the command line will
+        # get too long. See also _AddActions: cygwin's setup_env mustn't be called
+        # for every invocation or the command that sets the PATH will grow too
+        # long.
+        command = "\r\n".join(
+            [c + "\r\nif %errorlevel% neq 0 exit /b %errorlevel%" for c in commands]
+        )
+        _AddMSBuildAction(
+            spec,
+            primary_input,
+            inputs,
+            outputs,
+            command,
+            description,
+            sources_handled_by_action,
+            actions_spec,
+        )
+    return actions_spec, sources_handled_by_action
+
+
+def _AddMSBuildAction(
+    spec,
+    primary_input,
+    inputs,
+    outputs,
+    cmd,
+    description,
+    sources_handled_by_action,
+    actions_spec,
+):
+    command = MSVSSettings.ConvertVCMacrosToMSBuild(cmd)
+    primary_input = _FixPath(primary_input)
+    inputs_array = _FixPaths(inputs)
+    outputs_array = _FixPaths(outputs)
+    additional_inputs = ";".join([i for i in inputs_array if i != primary_input])
+    outputs = ";".join(outputs_array)
+    sources_handled_by_action.add(primary_input)
+    action_spec = ["CustomBuild", {"Include": primary_input}]
+    action_spec.extend(
+        # TODO(jeanluc) 'Document' for all or just if as_sources?
+        [
+            ["FileType", "Document"],
+            ["Command", command],
+            ["Message", description],
+            ["Outputs", outputs],
+        ]
+    )
+    if additional_inputs:
+        action_spec.append(["AdditionalInputs", additional_inputs])
+    actions_spec.append(action_spec)
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/msvs_test.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/msvs_test.py
new file mode 100755
index 0000000..e80b57f
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/msvs_test.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+""" Unit tests for the msvs.py file. """
+
+import gyp.generator.msvs as msvs
+import unittest
+
+from io import StringIO
+
+
+class TestSequenceFunctions(unittest.TestCase):
+    def setUp(self):
+        self.stderr = StringIO()
+
+    def test_GetLibraries(self):
+        self.assertEqual(msvs._GetLibraries({}), [])
+        self.assertEqual(msvs._GetLibraries({"libraries": []}), [])
+        self.assertEqual(
+            msvs._GetLibraries({"other": "foo", "libraries": ["a.lib"]}), ["a.lib"]
+        )
+        self.assertEqual(msvs._GetLibraries({"libraries": ["-la"]}), ["a.lib"])
+        self.assertEqual(
+            msvs._GetLibraries(
+                {
+                    "libraries": [
+                        "a.lib",
+                        "b.lib",
+                        "c.lib",
+                        "-lb.lib",
+                        "-lb.lib",
+                        "d.lib",
+                        "a.lib",
+                    ]
+                }
+            ),
+            ["c.lib", "b.lib", "d.lib", "a.lib"],
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/ninja.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/ninja.py
new file mode 100644
index 0000000..d173bf2
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/ninja.py
@@ -0,0 +1,2936 @@
+# Copyright (c) 2013 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+import collections
+import copy
+import hashlib
+import json
+import multiprocessing
+import os.path
+import re
+import signal
+import subprocess
+import sys
+import gyp
+import gyp.common
+import gyp.msvs_emulation
+import gyp.MSVSUtil as MSVSUtil
+import gyp.xcode_emulation
+
+from io import StringIO
+
+from gyp.common import GetEnvironFallback
+import gyp.ninja_syntax as ninja_syntax
+
+generator_default_variables = {
+    "EXECUTABLE_PREFIX": "",
+    "EXECUTABLE_SUFFIX": "",
+    "STATIC_LIB_PREFIX": "lib",
+    "STATIC_LIB_SUFFIX": ".a",
+    "SHARED_LIB_PREFIX": "lib",
+    # Gyp expects the following variables to be expandable by the build
+    # system to the appropriate locations.  Ninja prefers paths to be
+    # known at gyp time.  To resolve this, introduce special
+    # variables starting with $! and $| (which begin with a $ so gyp knows it
+    # should be treated specially, but is otherwise an invalid
+    # ninja/shell variable) that are passed to gyp here but expanded
+    # before writing out into the target .ninja files; see
+    # ExpandSpecial.
+    # $! is used for variables that represent a path and that can only appear at
+    # the start of a string, while $| is used for variables that can appear
+    # anywhere in a string.
+    "INTERMEDIATE_DIR": "$!INTERMEDIATE_DIR",
+    "SHARED_INTERMEDIATE_DIR": "$!PRODUCT_DIR/gen",
+    "PRODUCT_DIR": "$!PRODUCT_DIR",
+    "CONFIGURATION_NAME": "$|CONFIGURATION_NAME",
+    # Special variables that may be used by gyp 'rule' targets.
+    # We generate definitions for these variables on the fly when processing a
+    # rule.
+    "RULE_INPUT_ROOT": "${root}",
+    "RULE_INPUT_DIRNAME": "${dirname}",
+    "RULE_INPUT_PATH": "${source}",
+    "RULE_INPUT_EXT": "${ext}",
+    "RULE_INPUT_NAME": "${name}",
+}
+
+# Placates pylint.
+generator_additional_non_configuration_keys = []
+generator_additional_path_sections = []
+generator_extra_sources_for_rules = []
+generator_filelist_paths = None
+
+generator_supports_multiple_toolsets = gyp.common.CrossCompileRequested()
+
+
+def StripPrefix(arg, prefix):
+    if arg.startswith(prefix):
+        return arg[len(prefix) :]
+    return arg
+
+
+def QuoteShellArgument(arg, flavor):
+    """Quote a string such that it will be interpreted as a single argument
+    by the shell."""
+    # Rather than attempting to enumerate the bad shell characters, just
+    # allow common OK ones and quote anything else.
+    if re.match(r"^[a-zA-Z0-9_=.\\/-]+$", arg):
+        return arg  # No quoting necessary.
+    if flavor == "win":
+        return gyp.msvs_emulation.QuoteForRspFile(arg)
+    return "'" + arg.replace("'", "'" + '"\'"' + "'") + "'"
+
+
+def Define(d, flavor):
+    """Takes a preprocessor define and returns a -D parameter that's ninja- and
+    shell-escaped."""
+    if flavor == "win":
+        # cl.exe replaces literal # characters with = in preprocessor definitions for
+        # some reason. Octal-encode to work around that.
+        d = d.replace("#", "\\%03o" % ord("#"))
+    return QuoteShellArgument(ninja_syntax.escape("-D" + d), flavor)
+
+
+def AddArch(output, arch):
+    """Adds an arch string to an output path."""
+    output, extension = os.path.splitext(output)
+    return f"{output}.{arch}{extension}"
+
+
+class Target:
+    """Target represents the paths used within a single gyp target.
+
+    Conceptually, building a single target A is a series of steps:
+
+    1) actions/rules/copies  generates source/resources/etc.
+    2) compiles              generates .o files
+    3) link                  generates a binary (library/executable)
+    4) bundle                merges the above in a mac bundle
+
+    (Any of these steps can be optional.)
+
+    From a build ordering perspective, a dependent target B could just
+    depend on the last output of this series of steps.
+
+    But some dependent commands sometimes need to reach inside the box.
+    For example, when linking B it needs to get the path to the static
+    library generated by A.
+
+    This object stores those paths.  To keep things simple, member
+    variables only store concrete paths to single files, while methods
+    compute derived values like "the last output of the target".
+    """
+
+    def __init__(self, type):
+        # Gyp type ("static_library", etc.) of this target.
+        self.type = type
+        # File representing whether any input dependencies necessary for
+        # dependent actions have completed.
+        self.preaction_stamp = None
+        # File representing whether any input dependencies necessary for
+        # dependent compiles have completed.
+        self.precompile_stamp = None
+        # File representing the completion of actions/rules/copies, if any.
+        self.actions_stamp = None
+        # Path to the output of the link step, if any.
+        self.binary = None
+        # Path to the file representing the completion of building the bundle,
+        # if any.
+        self.bundle = None
+        # On Windows, incremental linking requires linking against all the .objs
+        # that compose a .lib (rather than the .lib itself). That list is stored
+        # here. In this case, we also need to save the compile_deps for the target,
+        # so that the target that directly depends on the .objs can also depend
+        # on those.
+        self.component_objs = None
+        self.compile_deps = None
+        # Windows only. The import .lib is the output of a build step, but
+        # because dependents only link against the lib (not both the lib and the
+        # dll) we keep track of the import library here.
+        self.import_lib = None
+        # Track if this target contains any C++ files, to decide if gcc or g++
+        # should be used for linking.
+        self.uses_cpp = False
+
+    def Linkable(self):
+        """Return true if this is a target that can be linked against."""
+        return self.type in ("static_library", "shared_library")
+
+    def UsesToc(self, flavor):
+        """Return true if the target should produce a restat rule based on a TOC
+        file."""
+        # For bundles, the .TOC should be produced for the binary, not for
+        # FinalOutput(). But the naive approach would put the TOC file into the
+        # bundle, so don't do this for bundles for now.
+        if flavor == "win" or self.bundle:
+            return False
+        return self.type in ("shared_library", "loadable_module")
+
+    def PreActionInput(self, flavor):
+        """Return the path, if any, that should be used as a dependency of
+        any dependent action step."""
+        if self.UsesToc(flavor):
+            return self.FinalOutput() + ".TOC"
+        return self.FinalOutput() or self.preaction_stamp
+
+    def PreCompileInput(self):
+        """Return the path, if any, that should be used as a dependency of
+        any dependent compile step."""
+        return self.actions_stamp or self.precompile_stamp
+
+    def FinalOutput(self):
+        """Return the last output of the target, which depends on all prior
+        steps."""
+        return self.bundle or self.binary or self.actions_stamp
+
+
+# A small discourse on paths as used within the Ninja build:
+# All files we produce (both at gyp and at build time) appear in the
+# build directory (e.g. out/Debug).
+#
+# Paths within a given .gyp file are always relative to the directory
+# containing the .gyp file.  Call these "gyp paths".  This includes
+# sources as well as the starting directory a given gyp rule/action
+# expects to be run from.  We call the path from the source root to
+# the gyp file the "base directory" within the per-.gyp-file
+# NinjaWriter code.
+#
+# All paths as written into the .ninja files are relative to the build
+# directory.  Call these paths "ninja paths".
+#
+# We translate between these two notions of paths with two helper
+# functions:
+#
+# - GypPathToNinja translates a gyp path (i.e. relative to the .gyp file)
+#   into the equivalent ninja path.
+#
+# - GypPathToUniqueOutput translates a gyp path into a ninja path to write
+#   an output file; the result can be namespaced such that it is unique
+#   to the input file name as well as the output target name.
+
+
+class NinjaWriter:
+    def __init__(
+        self,
+        hash_for_rules,
+        target_outputs,
+        base_dir,
+        build_dir,
+        output_file,
+        toplevel_build,
+        output_file_name,
+        flavor,
+        toplevel_dir=None,
+    ):
+        """
+        base_dir: path from source root to directory containing this gyp file,
+                  by gyp semantics, all input paths are relative to this
+        build_dir: path from source root to build output
+        toplevel_dir: path to the toplevel directory
+        """
+
+        self.hash_for_rules = hash_for_rules
+        self.target_outputs = target_outputs
+        self.base_dir = base_dir
+        self.build_dir = build_dir
+        self.ninja = ninja_syntax.Writer(output_file)
+        self.toplevel_build = toplevel_build
+        self.output_file_name = output_file_name
+
+        self.flavor = flavor
+        self.abs_build_dir = None
+        if toplevel_dir is not None:
+            self.abs_build_dir = os.path.abspath(os.path.join(toplevel_dir, build_dir))
+        self.obj_ext = ".obj" if flavor == "win" else ".o"
+        if flavor == "win":
+            # See docstring of msvs_emulation.GenerateEnvironmentFiles().
+            self.win_env = {}
+            for arch in ("x86", "x64"):
+                self.win_env[arch] = "environment." + arch
+
+        # Relative path from build output dir to base dir.
+        build_to_top = gyp.common.InvertRelativePath(build_dir, toplevel_dir)
+        self.build_to_base = os.path.join(build_to_top, base_dir)
+        # Relative path from base dir to build dir.
+        base_to_top = gyp.common.InvertRelativePath(base_dir, toplevel_dir)
+        self.base_to_build = os.path.join(base_to_top, build_dir)
+
+    def ExpandSpecial(self, path, product_dir=None):
+        """Expand specials like $!PRODUCT_DIR in |path|.
+
+        If |product_dir| is None, assumes the cwd is already the product
+        dir.  Otherwise, |product_dir| is the relative path to the product
+        dir.
+        """
+
+        PRODUCT_DIR = "$!PRODUCT_DIR"
+        if PRODUCT_DIR in path:
+            if product_dir:
+                path = path.replace(PRODUCT_DIR, product_dir)
+            else:
+                path = path.replace(PRODUCT_DIR + "/", "")
+                path = path.replace(PRODUCT_DIR + "\\", "")
+                path = path.replace(PRODUCT_DIR, ".")
+
+        INTERMEDIATE_DIR = "$!INTERMEDIATE_DIR"
+        if INTERMEDIATE_DIR in path:
+            int_dir = self.GypPathToUniqueOutput("gen")
+            # GypPathToUniqueOutput generates a path relative to the product dir,
+            # so insert product_dir in front if it is provided.
+            path = path.replace(
+                INTERMEDIATE_DIR, os.path.join(product_dir or "", int_dir)
+            )
+
+        CONFIGURATION_NAME = "$|CONFIGURATION_NAME"
+        path = path.replace(CONFIGURATION_NAME, self.config_name)
+
+        return path
+
+    def ExpandRuleVariables(self, path, root, dirname, source, ext, name):
+        if self.flavor == "win":
+            path = self.msvs_settings.ConvertVSMacros(path, config=self.config_name)
+        path = path.replace(generator_default_variables["RULE_INPUT_ROOT"], root)
+        path = path.replace(generator_default_variables["RULE_INPUT_DIRNAME"], dirname)
+        path = path.replace(generator_default_variables["RULE_INPUT_PATH"], source)
+        path = path.replace(generator_default_variables["RULE_INPUT_EXT"], ext)
+        path = path.replace(generator_default_variables["RULE_INPUT_NAME"], name)
+        return path
+
+    def GypPathToNinja(self, path, env=None):
+        """Translate a gyp path to a ninja path, optionally expanding environment
+        variable references in |path| with |env|.
+
+        See the above discourse on path conversions."""
+        if env:
+            if self.flavor == "mac":
+                path = gyp.xcode_emulation.ExpandEnvVars(path, env)
+            elif self.flavor == "win":
+                path = gyp.msvs_emulation.ExpandMacros(path, env)
+        if path.startswith("$!"):
+            expanded = self.ExpandSpecial(path)
+            if self.flavor == "win":
+                expanded = os.path.normpath(expanded)
+            return expanded
+        if "$|" in path:
+            path = self.ExpandSpecial(path)
+        assert "$" not in path, path
+        return os.path.normpath(os.path.join(self.build_to_base, path))
+
+    def GypPathToUniqueOutput(self, path, qualified=True):
+        """Translate a gyp path to a ninja path for writing output.
+
+        If qualified is True, qualify the resulting filename with the name
+        of the target.  This is necessary when e.g. compiling the same
+        path twice for two separate output targets.
+
+        See the above discourse on path conversions."""
+
+        path = self.ExpandSpecial(path)
+        assert not path.startswith("$"), path
+
+        # Translate the path following this scheme:
+        #   Input: foo/bar.gyp, target targ, references baz/out.o
+        #   Output: obj/foo/baz/targ.out.o (if qualified)
+        #           obj/foo/baz/out.o (otherwise)
+        #     (and obj.host instead of obj for cross-compiles)
+        #
+        # Why this scheme and not some other one?
+        # 1) for a given input, you can compute all derived outputs by matching
+        #    its path, even if the input is brought via a gyp file with '..'.
+        # 2) simple files like libraries and stamps have a simple filename.
+
+        obj = "obj"
+        if self.toolset != "target":
+            obj += "." + self.toolset
+
+        path_dir, path_basename = os.path.split(path)
+        assert not os.path.isabs(path_dir), (
+            "'%s' can not be absolute path (see crbug.com/462153)." % path_dir
+        )
+
+        if qualified:
+            path_basename = self.name + "." + path_basename
+        return os.path.normpath(
+            os.path.join(obj, self.base_dir, path_dir, path_basename)
+        )
+
+    def WriteCollapsedDependencies(self, name, targets, order_only=None):
+        """Given a list of targets, return a path for a single file
+        representing the result of building all the targets or None.
+
+        Uses a stamp file if necessary."""
+
+        assert targets == [item for item in targets if item], targets
+        if len(targets) == 0:
+            assert not order_only
+            return None
+        if len(targets) > 1 or order_only:
+            stamp = self.GypPathToUniqueOutput(name + ".stamp")
+            targets = self.ninja.build(stamp, "stamp", targets, order_only=order_only)
+            self.ninja.newline()
+        return targets[0]
+
+    def _SubninjaNameForArch(self, arch):
+        output_file_base = os.path.splitext(self.output_file_name)[0]
+        return f"{output_file_base}.{arch}.ninja"
+
+    def WriteSpec(self, spec, config_name, generator_flags):
+        """The main entry point for NinjaWriter: write the build rules for a spec.
+
+        Returns a Target object, which represents the output paths for this spec.
+        Returns None if there are no outputs (e.g. a settings-only 'none' type
+        target)."""
+
+        self.config_name = config_name
+        self.name = spec["target_name"]
+        self.toolset = spec["toolset"]
+        config = spec["configurations"][config_name]
+        self.target = Target(spec["type"])
+        self.is_standalone_static_library = bool(
+            spec.get("standalone_static_library", 0)
+        )
+
+        self.target_rpath = generator_flags.get("target_rpath", r"\$$ORIGIN/lib/")
+
+        self.is_mac_bundle = gyp.xcode_emulation.IsMacBundle(self.flavor, spec)
+        self.xcode_settings = self.msvs_settings = None
+        if self.flavor == "mac":
+            self.xcode_settings = gyp.xcode_emulation.XcodeSettings(spec)
+            mac_toolchain_dir = generator_flags.get("mac_toolchain_dir", None)
+            if mac_toolchain_dir:
+                self.xcode_settings.mac_toolchain_dir = mac_toolchain_dir
+
+        if self.flavor == "win":
+            self.msvs_settings = gyp.msvs_emulation.MsvsSettings(spec, generator_flags)
+            arch = self.msvs_settings.GetArch(config_name)
+            self.ninja.variable("arch", self.win_env[arch])
+            self.ninja.variable("cc", "$cl_" + arch)
+            self.ninja.variable("cxx", "$cl_" + arch)
+            self.ninja.variable("cc_host", "$cl_" + arch)
+            self.ninja.variable("cxx_host", "$cl_" + arch)
+            self.ninja.variable("asm", "$ml_" + arch)
+
+        if self.flavor == "mac":
+            self.archs = self.xcode_settings.GetActiveArchs(config_name)
+            if len(self.archs) > 1:
+                self.arch_subninjas = {
+                    arch: ninja_syntax.Writer(
+                        OpenOutput(
+                            os.path.join(
+                                self.toplevel_build, self._SubninjaNameForArch(arch)
+                            ),
+                            "w",
+                        )
+                    )
+                    for arch in self.archs
+                }
+
+        # Compute predepends for all rules.
+        # actions_depends is the dependencies this target depends on before running
+        # any of its action/rule/copy steps.
+        # compile_depends is the dependencies this target depends on before running
+        # any of its compile steps.
+        actions_depends = []
+        compile_depends = []
+        # TODO(evan): it is rather confusing which things are lists and which
+        # are strings.  Fix these.
+        if "dependencies" in spec:
+            for dep in spec["dependencies"]:
+                if dep in self.target_outputs:
+                    target = self.target_outputs[dep]
+                    actions_depends.append(target.PreActionInput(self.flavor))
+                    compile_depends.append(target.PreCompileInput())
+                    if target.uses_cpp:
+                        self.target.uses_cpp = True
+            actions_depends = [item for item in actions_depends if item]
+            compile_depends = [item for item in compile_depends if item]
+            actions_depends = self.WriteCollapsedDependencies(
+                "actions_depends", actions_depends
+            )
+            compile_depends = self.WriteCollapsedDependencies(
+                "compile_depends", compile_depends
+            )
+            self.target.preaction_stamp = actions_depends
+            self.target.precompile_stamp = compile_depends
+
+        # Write out actions, rules, and copies.  These must happen before we
+        # compile any sources, so compute a list of predependencies for sources
+        # while we do it.
+        extra_sources = []
+        mac_bundle_depends = []
+        self.target.actions_stamp = self.WriteActionsRulesCopies(
+            spec, extra_sources, actions_depends, mac_bundle_depends
+        )
+
+        # If we have actions/rules/copies, we depend directly on those, but
+        # otherwise we depend on dependent target's actions/rules/copies etc.
+        # We never need to explicitly depend on previous target's link steps,
+        # because no compile ever depends on them.
+        compile_depends_stamp = self.target.actions_stamp or compile_depends
+
+        # Write out the compilation steps, if any.
+        link_deps = []
+        try:
+            sources = extra_sources + spec.get("sources", [])
+        except TypeError:
+            print("extra_sources: ", str(extra_sources))
+            print('spec.get("sources"): ', str(spec.get("sources")))
+            raise
+        if sources:
+            if self.flavor == "mac" and len(self.archs) > 1:
+                # Write subninja file containing compile and link commands scoped to
+                # a single arch if a fat binary is being built.
+                for arch in self.archs:
+                    self.ninja.subninja(self._SubninjaNameForArch(arch))
+
+            pch = None
+            if self.flavor == "win":
+                gyp.msvs_emulation.VerifyMissingSources(
+                    sources, self.abs_build_dir, generator_flags, self.GypPathToNinja
+                )
+                pch = gyp.msvs_emulation.PrecompiledHeader(
+                    self.msvs_settings,
+                    config_name,
+                    self.GypPathToNinja,
+                    self.GypPathToUniqueOutput,
+                    self.obj_ext,
+                )
+            else:
+                pch = gyp.xcode_emulation.MacPrefixHeader(
+                    self.xcode_settings,
+                    self.GypPathToNinja,
+                    lambda path, lang: self.GypPathToUniqueOutput(path + "-" + lang),
+                )
+            link_deps = self.WriteSources(
+                self.ninja,
+                config_name,
+                config,
+                sources,
+                compile_depends_stamp,
+                pch,
+                spec,
+            )
+            # Some actions/rules output 'sources' that are already object files.
+            obj_outputs = [f for f in sources if f.endswith(self.obj_ext)]
+            if obj_outputs:
+                if self.flavor != "mac" or len(self.archs) == 1:
+                    link_deps += [self.GypPathToNinja(o) for o in obj_outputs]
+                else:
+                    print(
+                        "Warning: Actions/rules writing object files don't work with "
+                        "multiarch targets, dropping. (target %s)" % spec["target_name"]
+                    )
+        elif self.flavor == "mac" and len(self.archs) > 1:
+            link_deps = collections.defaultdict(list)
+
+        compile_deps = self.target.actions_stamp or actions_depends
+        if self.flavor == "win" and self.target.type == "static_library":
+            self.target.component_objs = link_deps
+            self.target.compile_deps = compile_deps
+
+        # Write out a link step, if needed.
+        output = None
+        is_empty_bundle = not link_deps and not mac_bundle_depends
+        if link_deps or self.target.actions_stamp or actions_depends:
+            output = self.WriteTarget(
+                spec, config_name, config, link_deps, compile_deps
+            )
+            if self.is_mac_bundle:
+                mac_bundle_depends.append(output)
+
+        # Bundle all of the above together, if needed.
+        if self.is_mac_bundle:
+            output = self.WriteMacBundle(spec, mac_bundle_depends, is_empty_bundle)
+
+        if not output:
+            return None
+
+        assert self.target.FinalOutput(), output
+        return self.target
+
+    def _WinIdlRule(self, source, prebuild, outputs):
+        """Handle the implicit VS .idl rule for one source file. Fills |outputs|
+        with files that are generated."""
+        outdir, output, vars, flags = self.msvs_settings.GetIdlBuildData(
+            source, self.config_name
+        )
+        outdir = self.GypPathToNinja(outdir)
+
+        def fix_path(path, rel=None):
+            path = os.path.join(outdir, path)
+            dirname, basename = os.path.split(source)
+            root, ext = os.path.splitext(basename)
+            path = self.ExpandRuleVariables(path, root, dirname, source, ext, basename)
+            if rel:
+                path = os.path.relpath(path, rel)
+            return path
+
+        vars = [(name, fix_path(value, outdir)) for name, value in vars]
+        output = [fix_path(p) for p in output]
+        vars.append(("outdir", outdir))
+        vars.append(("idlflags", flags))
+        input = self.GypPathToNinja(source)
+        self.ninja.build(output, "idl", input, variables=vars, order_only=prebuild)
+        outputs.extend(output)
+
+    def WriteWinIdlFiles(self, spec, prebuild):
+        """Writes rules to match MSVS's implicit idl handling."""
+        assert self.flavor == "win"
+        if self.msvs_settings.HasExplicitIdlRulesOrActions(spec):
+            return []
+        outputs = []
+        for source in filter(lambda x: x.endswith(".idl"), spec["sources"]):
+            self._WinIdlRule(source, prebuild, outputs)
+        return outputs
+
+    def WriteActionsRulesCopies(
+        self, spec, extra_sources, prebuild, mac_bundle_depends
+    ):
+        """Write out the Actions, Rules, and Copies steps.  Return a path
+        representing the outputs of these steps."""
+        outputs = []
+        if self.is_mac_bundle:
+            mac_bundle_resources = spec.get("mac_bundle_resources", [])[:]
+        else:
+            mac_bundle_resources = []
+        extra_mac_bundle_resources = []
+
+        if "actions" in spec:
+            outputs += self.WriteActions(
+                spec["actions"], extra_sources, prebuild, extra_mac_bundle_resources
+            )
+        if "rules" in spec:
+            outputs += self.WriteRules(
+                spec["rules"],
+                extra_sources,
+                prebuild,
+                mac_bundle_resources,
+                extra_mac_bundle_resources,
+            )
+        if "copies" in spec:
+            outputs += self.WriteCopies(spec["copies"], prebuild, mac_bundle_depends)
+
+        if "sources" in spec and self.flavor == "win":
+            outputs += self.WriteWinIdlFiles(spec, prebuild)
+
+        if self.xcode_settings and self.xcode_settings.IsIosFramework():
+            self.WriteiOSFrameworkHeaders(spec, outputs, prebuild)
+
+        stamp = self.WriteCollapsedDependencies("actions_rules_copies", outputs)
+
+        if self.is_mac_bundle:
+            xcassets = self.WriteMacBundleResources(
+                extra_mac_bundle_resources + mac_bundle_resources, mac_bundle_depends
+            )
+            partial_info_plist = self.WriteMacXCassets(xcassets, mac_bundle_depends)
+            self.WriteMacInfoPlist(partial_info_plist, mac_bundle_depends)
+
+        return stamp
+
+    def GenerateDescription(self, verb, message, fallback):
+        """Generate and return a description of a build step.
+
+        |verb| is the short summary, e.g. ACTION or RULE.
+        |message| is a hand-written description, or None if not available.
+        |fallback| is the gyp-level name of the step, usable as a fallback.
+        """
+        if self.toolset != "target":
+            verb += "(%s)" % self.toolset
+        if message:
+            return f"{verb} {self.ExpandSpecial(message)}"
+        else:
+            return f"{verb} {self.name}: {fallback}"
+
+    def WriteActions(
+        self, actions, extra_sources, prebuild, extra_mac_bundle_resources
+    ):
+        # Actions cd into the base directory.
+        env = self.GetToolchainEnv()
+        all_outputs = []
+        for action in actions:
+            # First write out a rule for the action.
+            name = "{}_{}".format(action["action_name"], self.hash_for_rules)
+            description = self.GenerateDescription(
+                "ACTION", action.get("message", None), name
+            )
+            win_shell_flags = (
+                self.msvs_settings.GetRuleShellFlags(action)
+                if self.flavor == "win"
+                else None
+            )
+            args = action["action"]
+            depfile = action.get("depfile", None)
+            if depfile:
+                depfile = self.ExpandSpecial(depfile, self.base_to_build)
+            pool = "console" if int(action.get("ninja_use_console", 0)) else None
+            rule_name, _ = self.WriteNewNinjaRule(
+                name, args, description, win_shell_flags, env, pool, depfile=depfile
+            )
+
+            inputs = [self.GypPathToNinja(i, env) for i in action["inputs"]]
+            if int(action.get("process_outputs_as_sources", False)):
+                extra_sources += action["outputs"]
+            if int(action.get("process_outputs_as_mac_bundle_resources", False)):
+                extra_mac_bundle_resources += action["outputs"]
+            outputs = [self.GypPathToNinja(o, env) for o in action["outputs"]]
+
+            # Then write out an edge using the rule.
+            self.ninja.build(outputs, rule_name, inputs, order_only=prebuild)
+            all_outputs += outputs
+
+            self.ninja.newline()
+
+        return all_outputs
+
+    def WriteRules(
+        self,
+        rules,
+        extra_sources,
+        prebuild,
+        mac_bundle_resources,
+        extra_mac_bundle_resources,
+    ):
+        env = self.GetToolchainEnv()
+        all_outputs = []
+        for rule in rules:
+            # Skip a rule with no action and no inputs.
+            if "action" not in rule and not rule.get("rule_sources", []):
+                continue
+
+            # First write out a rule for the rule action.
+            name = "{}_{}".format(rule["rule_name"], self.hash_for_rules)
+
+            args = rule["action"]
+            description = self.GenerateDescription(
+                "RULE",
+                rule.get("message", None),
+                ("%s " + generator_default_variables["RULE_INPUT_PATH"]) % name,
+            )
+            win_shell_flags = (
+                self.msvs_settings.GetRuleShellFlags(rule)
+                if self.flavor == "win"
+                else None
+            )
+            pool = "console" if int(rule.get("ninja_use_console", 0)) else None
+            rule_name, args = self.WriteNewNinjaRule(
+                name, args, description, win_shell_flags, env, pool
+            )
+
+            # TODO: if the command references the outputs directly, we should
+            # simplify it to just use $out.
+
+            # Rules can potentially make use of some special variables which
+            # must vary per source file.
+            # Compute the list of variables we'll need to provide.
+            special_locals = ("source", "root", "dirname", "ext", "name")
+            needed_variables = {"source"}
+            for argument in args:
+                for var in special_locals:
+                    if "${%s}" % var in argument:
+                        needed_variables.add(var)
+            needed_variables = sorted(needed_variables)
+
+            def cygwin_munge(path):
+                # pylint: disable=cell-var-from-loop
+                if win_shell_flags and win_shell_flags.cygwin:
+                    return path.replace("\\", "/")
+                return path
+
+            inputs = [self.GypPathToNinja(i, env) for i in rule.get("inputs", [])]
+
+            # If there are n source files matching the rule, and m additional rule
+            # inputs, then adding 'inputs' to each build edge written below will
+            # write m * n inputs. Collapsing reduces this to m + n.
+            sources = rule.get("rule_sources", [])
+            num_inputs = len(inputs)
+            if prebuild:
+                num_inputs += 1
+            if num_inputs > 2 and len(sources) > 2:
+                inputs = [
+                    self.WriteCollapsedDependencies(
+                        rule["rule_name"], inputs, order_only=prebuild
+                    )
+                ]
+                prebuild = []
+
+            # For each source file, write an edge that generates all the outputs.
+            for source in sources:
+                source = os.path.normpath(source)
+                dirname, basename = os.path.split(source)
+                root, ext = os.path.splitext(basename)
+
+                # Gather the list of inputs and outputs, expanding $vars if possible.
+                outputs = [
+                    self.ExpandRuleVariables(o, root, dirname, source, ext, basename)
+                    for o in rule["outputs"]
+                ]
+
+                if int(rule.get("process_outputs_as_sources", False)):
+                    extra_sources += outputs
+
+                was_mac_bundle_resource = source in mac_bundle_resources
+                if was_mac_bundle_resource or int(
+                    rule.get("process_outputs_as_mac_bundle_resources", False)
+                ):
+                    extra_mac_bundle_resources += outputs
+                    # Note: This is n_resources * n_outputs_in_rule.
+                    # Put to-be-removed items in a set and
+                    # remove them all in a single pass
+                    # if this becomes a performance issue.
+                    if was_mac_bundle_resource:
+                        mac_bundle_resources.remove(source)
+
+                extra_bindings = []
+                for var in needed_variables:
+                    if var == "root":
+                        extra_bindings.append(("root", cygwin_munge(root)))
+                    elif var == "dirname":
+                        # '$dirname' is a parameter to the rule action, which means
+                        # it shouldn't be converted to a Ninja path.  But we don't
+                        # want $!PRODUCT_DIR in there either.
+                        dirname_expanded = self.ExpandSpecial(
+                            dirname, self.base_to_build
+                        )
+                        extra_bindings.append(
+                            ("dirname", cygwin_munge(dirname_expanded))
+                        )
+                    elif var == "source":
+                        # '$source' is a parameter to the rule action, which means
+                        # it shouldn't be converted to a Ninja path.  But we don't
+                        # want $!PRODUCT_DIR in there either.
+                        source_expanded = self.ExpandSpecial(source, self.base_to_build)
+                        extra_bindings.append(("source", cygwin_munge(source_expanded)))
+                    elif var == "ext":
+                        extra_bindings.append(("ext", ext))
+                    elif var == "name":
+                        extra_bindings.append(("name", cygwin_munge(basename)))
+                    else:
+                        assert var is None, repr(var)
+
+                outputs = [self.GypPathToNinja(o, env) for o in outputs]
+                if self.flavor == "win":
+                    # WriteNewNinjaRule uses unique_name to create a rsp file on win.
+                    extra_bindings.append(
+                        ("unique_name", hashlib.md5(outputs[0]).hexdigest())
+                    )
+
+                self.ninja.build(
+                    outputs,
+                    rule_name,
+                    self.GypPathToNinja(source),
+                    implicit=inputs,
+                    order_only=prebuild,
+                    variables=extra_bindings,
+                )
+
+                all_outputs.extend(outputs)
+
+        return all_outputs
+
+    def WriteCopies(self, copies, prebuild, mac_bundle_depends):
+        outputs = []
+        if self.xcode_settings:
+            extra_env = self.xcode_settings.GetPerTargetSettings()
+            env = self.GetToolchainEnv(additional_settings=extra_env)
+        else:
+            env = self.GetToolchainEnv()
+        for to_copy in copies:
+            for path in to_copy["files"]:
+                # Normalize the path so trailing slashes don't confuse us.
+                path = os.path.normpath(path)
+                basename = os.path.split(path)[1]
+                src = self.GypPathToNinja(path, env)
+                dst = self.GypPathToNinja(
+                    os.path.join(to_copy["destination"], basename), env
+                )
+                outputs += self.ninja.build(dst, "copy", src, order_only=prebuild)
+                if self.is_mac_bundle:
+                    # gyp has mac_bundle_resources to copy things into a bundle's
+                    # Resources folder, but there's no built-in way to copy files
+                    # to other places in the bundle.
+                    # Hence, some targets use copies for this.
+                    # Check if this file is copied into the current bundle,
+                    # and if so add it to the bundle depends so
+                    # that dependent targets get rebuilt if the copy input changes.
+                    if dst.startswith(
+                        self.xcode_settings.GetBundleContentsFolderPath()
+                    ):
+                        mac_bundle_depends.append(dst)
+
+        return outputs
+
+    def WriteiOSFrameworkHeaders(self, spec, outputs, prebuild):
+        """Prebuild steps to generate hmap files and copy headers to destination."""
+        framework = self.ComputeMacBundleOutput()
+        all_sources = spec["sources"]
+        copy_headers = spec["mac_framework_headers"]
+        output = self.GypPathToUniqueOutput("headers.hmap")
+        self.xcode_settings.header_map_path = output
+        all_headers = map(
+            self.GypPathToNinja, filter(lambda x: x.endswith(".h"), all_sources)
+        )
+        variables = [
+            ("framework", framework),
+            ("copy_headers", map(self.GypPathToNinja, copy_headers)),
+        ]
+        outputs.extend(
+            self.ninja.build(
+                output,
+                "compile_ios_framework_headers",
+                all_headers,
+                variables=variables,
+                order_only=prebuild,
+            )
+        )
+
+    def WriteMacBundleResources(self, resources, bundle_depends):
+        """Writes ninja edges for 'mac_bundle_resources'."""
+        xcassets = []
+
+        extra_env = self.xcode_settings.GetPerTargetSettings()
+        env = self.GetSortedXcodeEnv(additional_settings=extra_env)
+        env = self.ComputeExportEnvString(env)
+        isBinary = self.xcode_settings.IsBinaryOutputFormat(self.config_name)
+
+        for output, res in gyp.xcode_emulation.GetMacBundleResources(
+            generator_default_variables["PRODUCT_DIR"],
+            self.xcode_settings,
+            map(self.GypPathToNinja, resources),
+        ):
+            output = self.ExpandSpecial(output)
+            if os.path.splitext(output)[-1] != ".xcassets":
+                self.ninja.build(
+                    output,
+                    "mac_tool",
+                    res,
+                    variables=[
+                        ("mactool_cmd", "copy-bundle-resource"),
+                        ("env", env),
+                        ("binary", isBinary),
+                    ],
+                )
+                bundle_depends.append(output)
+            else:
+                xcassets.append(res)
+        return xcassets
+
+    def WriteMacXCassets(self, xcassets, bundle_depends):
+        """Writes ninja edges for 'mac_bundle_resources' .xcassets files.
+
+        This add an invocation of 'actool' via the 'mac_tool.py' helper script.
+        It assumes that the assets catalogs define at least one imageset and
+        thus an Assets.car file will be generated in the application resources
+        directory. If this is not the case, then the build will probably be done
+        at each invocation of ninja."""
+        if not xcassets:
+            return
+
+        extra_arguments = {}
+        settings_to_arg = {
+            "XCASSETS_APP_ICON": "app-icon",
+            "XCASSETS_LAUNCH_IMAGE": "launch-image",
+        }
+        settings = self.xcode_settings.xcode_settings[self.config_name]
+        for settings_key, arg_name in settings_to_arg.items():
+            value = settings.get(settings_key)
+            if value:
+                extra_arguments[arg_name] = value
+
+        partial_info_plist = None
+        if extra_arguments:
+            partial_info_plist = self.GypPathToUniqueOutput(
+                "assetcatalog_generated_info.plist"
+            )
+            extra_arguments["output-partial-info-plist"] = partial_info_plist
+
+        outputs = []
+        outputs.append(
+            os.path.join(self.xcode_settings.GetBundleResourceFolder(), "Assets.car")
+        )
+        if partial_info_plist:
+            outputs.append(partial_info_plist)
+
+        keys = QuoteShellArgument(json.dumps(extra_arguments), self.flavor)
+        extra_env = self.xcode_settings.GetPerTargetSettings()
+        env = self.GetSortedXcodeEnv(additional_settings=extra_env)
+        env = self.ComputeExportEnvString(env)
+
+        bundle_depends.extend(
+            self.ninja.build(
+                outputs,
+                "compile_xcassets",
+                xcassets,
+                variables=[("env", env), ("keys", keys)],
+            )
+        )
+        return partial_info_plist
+
+    def WriteMacInfoPlist(self, partial_info_plist, bundle_depends):
+        """Write build rules for bundle Info.plist files."""
+        info_plist, out, defines, extra_env = gyp.xcode_emulation.GetMacInfoPlist(
+            generator_default_variables["PRODUCT_DIR"],
+            self.xcode_settings,
+            self.GypPathToNinja,
+        )
+        if not info_plist:
+            return
+        out = self.ExpandSpecial(out)
+        if defines:
+            # Create an intermediate file to store preprocessed results.
+            intermediate_plist = self.GypPathToUniqueOutput(
+                os.path.basename(info_plist)
+            )
+            defines = " ".join([Define(d, self.flavor) for d in defines])
+            info_plist = self.ninja.build(
+                intermediate_plist,
+                "preprocess_infoplist",
+                info_plist,
+                variables=[("defines", defines)],
+            )
+
+        env = self.GetSortedXcodeEnv(additional_settings=extra_env)
+        env = self.ComputeExportEnvString(env)
+
+        if partial_info_plist:
+            intermediate_plist = self.GypPathToUniqueOutput("merged_info.plist")
+            info_plist = self.ninja.build(
+                intermediate_plist, "merge_infoplist", [partial_info_plist, info_plist]
+            )
+
+        keys = self.xcode_settings.GetExtraPlistItems(self.config_name)
+        keys = QuoteShellArgument(json.dumps(keys), self.flavor)
+        isBinary = self.xcode_settings.IsBinaryOutputFormat(self.config_name)
+        self.ninja.build(
+            out,
+            "copy_infoplist",
+            info_plist,
+            variables=[("env", env), ("keys", keys), ("binary", isBinary)],
+        )
+        bundle_depends.append(out)
+
+    def WriteSources(
+        self,
+        ninja_file,
+        config_name,
+        config,
+        sources,
+        predepends,
+        precompiled_header,
+        spec,
+    ):
+        """Write build rules to compile all of |sources|."""
+        if self.toolset == "host":
+            self.ninja.variable("ar", "$ar_host")
+            self.ninja.variable("cc", "$cc_host")
+            self.ninja.variable("cxx", "$cxx_host")
+            self.ninja.variable("ld", "$ld_host")
+            self.ninja.variable("ldxx", "$ldxx_host")
+            self.ninja.variable("nm", "$nm_host")
+            self.ninja.variable("readelf", "$readelf_host")
+
+        if self.flavor != "mac" or len(self.archs) == 1:
+            return self.WriteSourcesForArch(
+                self.ninja,
+                config_name,
+                config,
+                sources,
+                predepends,
+                precompiled_header,
+                spec,
+            )
+        else:
+            return {
+                arch: self.WriteSourcesForArch(
+                    self.arch_subninjas[arch],
+                    config_name,
+                    config,
+                    sources,
+                    predepends,
+                    precompiled_header,
+                    spec,
+                    arch=arch,
+                )
+                for arch in self.archs
+            }
+
+    def WriteSourcesForArch(
+        self,
+        ninja_file,
+        config_name,
+        config,
+        sources,
+        predepends,
+        precompiled_header,
+        spec,
+        arch=None,
+    ):
+        """Write build rules to compile all of |sources|."""
+
+        extra_defines = []
+        if self.flavor == "mac":
+            cflags = self.xcode_settings.GetCflags(config_name, arch=arch)
+            cflags_c = self.xcode_settings.GetCflagsC(config_name)
+            cflags_cc = self.xcode_settings.GetCflagsCC(config_name)
+            cflags_objc = ["$cflags_c"] + self.xcode_settings.GetCflagsObjC(config_name)
+            cflags_objcc = ["$cflags_cc"] + self.xcode_settings.GetCflagsObjCC(
+                config_name
+            )
+        elif self.flavor == "win":
+            asmflags = self.msvs_settings.GetAsmflags(config_name)
+            cflags = self.msvs_settings.GetCflags(config_name)
+            cflags_c = self.msvs_settings.GetCflagsC(config_name)
+            cflags_cc = self.msvs_settings.GetCflagsCC(config_name)
+            extra_defines = self.msvs_settings.GetComputedDefines(config_name)
+            # See comment at cc_command for why there's two .pdb files.
+            pdbpath_c = pdbpath_cc = self.msvs_settings.GetCompilerPdbName(
+                config_name, self.ExpandSpecial
+            )
+            if not pdbpath_c:
+                obj = "obj"
+                if self.toolset != "target":
+                    obj += "." + self.toolset
+                pdbpath = os.path.normpath(os.path.join(obj, self.base_dir, self.name))
+                pdbpath_c = pdbpath + ".c.pdb"
+                pdbpath_cc = pdbpath + ".cc.pdb"
+            self.WriteVariableList(ninja_file, "pdbname_c", [pdbpath_c])
+            self.WriteVariableList(ninja_file, "pdbname_cc", [pdbpath_cc])
+            self.WriteVariableList(ninja_file, "pchprefix", [self.name])
+        else:
+            cflags = config.get("cflags", [])
+            cflags_c = config.get("cflags_c", [])
+            cflags_cc = config.get("cflags_cc", [])
+
+        # Respect environment variables related to build, but target-specific
+        # flags can still override them.
+        if self.toolset == "target":
+            cflags_c = (
+                os.environ.get("CPPFLAGS", "").split()
+                + os.environ.get("CFLAGS", "").split()
+                + cflags_c
+            )
+            cflags_cc = (
+                os.environ.get("CPPFLAGS", "").split()
+                + os.environ.get("CXXFLAGS", "").split()
+                + cflags_cc
+            )
+        elif self.toolset == "host":
+            cflags_c = (
+                os.environ.get("CPPFLAGS_host", "").split()
+                + os.environ.get("CFLAGS_host", "").split()
+                + cflags_c
+            )
+            cflags_cc = (
+                os.environ.get("CPPFLAGS_host", "").split()
+                + os.environ.get("CXXFLAGS_host", "").split()
+                + cflags_cc
+            )
+
+        defines = config.get("defines", []) + extra_defines
+        self.WriteVariableList(
+            ninja_file, "defines", [Define(d, self.flavor) for d in defines]
+        )
+        if self.flavor == "win":
+            self.WriteVariableList(
+                ninja_file, "asmflags", map(self.ExpandSpecial, asmflags)
+            )
+            self.WriteVariableList(
+                ninja_file,
+                "rcflags",
+                [
+                    QuoteShellArgument(self.ExpandSpecial(f), self.flavor)
+                    for f in self.msvs_settings.GetRcflags(
+                        config_name, self.GypPathToNinja
+                    )
+                ],
+            )
+
+        include_dirs = config.get("include_dirs", [])
+
+        env = self.GetToolchainEnv()
+        if self.flavor == "win":
+            include_dirs = self.msvs_settings.AdjustIncludeDirs(
+                include_dirs, config_name
+            )
+        self.WriteVariableList(
+            ninja_file,
+            "includes",
+            [
+                QuoteShellArgument("-I" + self.GypPathToNinja(i, env), self.flavor)
+                for i in include_dirs
+            ],
+        )
+
+        if self.flavor == "win":
+            midl_include_dirs = config.get("midl_include_dirs", [])
+            midl_include_dirs = self.msvs_settings.AdjustMidlIncludeDirs(
+                midl_include_dirs, config_name
+            )
+            self.WriteVariableList(
+                ninja_file,
+                "midl_includes",
+                [
+                    QuoteShellArgument("-I" + self.GypPathToNinja(i, env), self.flavor)
+                    for i in midl_include_dirs
+                ],
+            )
+
+        pch_commands = precompiled_header.GetPchBuildCommands(arch)
+        if self.flavor == "mac":
+            # Most targets use no precompiled headers, so only write these if needed.
+            for ext, var in [
+                ("c", "cflags_pch_c"),
+                ("cc", "cflags_pch_cc"),
+                ("m", "cflags_pch_objc"),
+                ("mm", "cflags_pch_objcc"),
+            ]:
+                include = precompiled_header.GetInclude(ext, arch)
+                if include:
+                    ninja_file.variable(var, include)
+
+        arflags = config.get("arflags", [])
+
+        self.WriteVariableList(ninja_file, "cflags", map(self.ExpandSpecial, cflags))
+        self.WriteVariableList(
+            ninja_file, "cflags_c", map(self.ExpandSpecial, cflags_c)
+        )
+        self.WriteVariableList(
+            ninja_file, "cflags_cc", map(self.ExpandSpecial, cflags_cc)
+        )
+        if self.flavor == "mac":
+            self.WriteVariableList(
+                ninja_file, "cflags_objc", map(self.ExpandSpecial, cflags_objc)
+            )
+            self.WriteVariableList(
+                ninja_file, "cflags_objcc", map(self.ExpandSpecial, cflags_objcc)
+            )
+        self.WriteVariableList(ninja_file, "arflags", map(self.ExpandSpecial, arflags))
+        ninja_file.newline()
+        outputs = []
+        has_rc_source = False
+        for source in sources:
+            filename, ext = os.path.splitext(source)
+            ext = ext[1:]
+            obj_ext = self.obj_ext
+            if ext in ("cc", "cpp", "cxx"):
+                command = "cxx"
+                self.target.uses_cpp = True
+            elif ext == "c" or (ext == "S" and self.flavor != "win"):
+                command = "cc"
+            elif ext == "s" and self.flavor != "win":  # Doesn't generate .o.d files.
+                command = "cc_s"
+            elif (
+                self.flavor == "win"
+                and ext in ("asm", "S")
+                and not self.msvs_settings.HasExplicitAsmRules(spec)
+            ):
+                command = "asm"
+                # Add the _asm suffix as msvs is capable of handling .cc and
+                # .asm files of the same name without collision.
+                obj_ext = "_asm.obj"
+            elif self.flavor == "mac" and ext == "m":
+                command = "objc"
+            elif self.flavor == "mac" and ext == "mm":
+                command = "objcxx"
+                self.target.uses_cpp = True
+            elif self.flavor == "win" and ext == "rc":
+                command = "rc"
+                obj_ext = ".res"
+                has_rc_source = True
+            else:
+                # Ignore unhandled extensions.
+                continue
+            input = self.GypPathToNinja(source)
+            output = self.GypPathToUniqueOutput(filename + obj_ext)
+            if arch is not None:
+                output = AddArch(output, arch)
+            implicit = precompiled_header.GetObjDependencies([input], [output], arch)
+            variables = []
+            if self.flavor == "win":
+                variables, output, implicit = precompiled_header.GetFlagsModifications(
+                    input,
+                    output,
+                    implicit,
+                    command,
+                    cflags_c,
+                    cflags_cc,
+                    self.ExpandSpecial,
+                )
+            ninja_file.build(
+                output,
+                command,
+                input,
+                implicit=[gch for _, _, gch in implicit],
+                order_only=predepends,
+                variables=variables,
+            )
+            outputs.append(output)
+
+        if has_rc_source:
+            resource_include_dirs = config.get("resource_include_dirs", include_dirs)
+            self.WriteVariableList(
+                ninja_file,
+                "resource_includes",
+                [
+                    QuoteShellArgument("-I" + self.GypPathToNinja(i, env), self.flavor)
+                    for i in resource_include_dirs
+                ],
+            )
+
+        self.WritePchTargets(ninja_file, pch_commands)
+
+        ninja_file.newline()
+        return outputs
+
+    def WritePchTargets(self, ninja_file, pch_commands):
+        """Writes ninja rules to compile prefix headers."""
+        if not pch_commands:
+            return
+
+        for gch, lang_flag, lang, input in pch_commands:
+            var_name = {
+                "c": "cflags_pch_c",
+                "cc": "cflags_pch_cc",
+                "m": "cflags_pch_objc",
+                "mm": "cflags_pch_objcc",
+            }[lang]
+
+            map = {
+                "c": "cc",
+                "cc": "cxx",
+                "m": "objc",
+                "mm": "objcxx",
+            }
+            cmd = map.get(lang)
+            ninja_file.build(gch, cmd, input, variables=[(var_name, lang_flag)])
+
+    def WriteLink(self, spec, config_name, config, link_deps, compile_deps):
+        """Write out a link step. Fills out target.binary. """
+        if self.flavor != "mac" or len(self.archs) == 1:
+            return self.WriteLinkForArch(
+                self.ninja, spec, config_name, config, link_deps, compile_deps
+            )
+        else:
+            output = self.ComputeOutput(spec)
+            inputs = [
+                self.WriteLinkForArch(
+                    self.arch_subninjas[arch],
+                    spec,
+                    config_name,
+                    config,
+                    link_deps[arch],
+                    compile_deps,
+                    arch=arch,
+                )
+                for arch in self.archs
+            ]
+            extra_bindings = []
+            build_output = output
+            if not self.is_mac_bundle:
+                self.AppendPostbuildVariable(extra_bindings, spec, output, output)
+
+            # TODO(yyanagisawa): more work needed to fix:
+            # https://code.google.com/p/gyp/issues/detail?id=411
+            if (
+                spec["type"] in ("shared_library", "loadable_module")
+                and not self.is_mac_bundle
+            ):
+                extra_bindings.append(("lib", output))
+                self.ninja.build(
+                    [output, output + ".TOC"],
+                    "solipo",
+                    inputs,
+                    variables=extra_bindings,
+                )
+            else:
+                self.ninja.build(build_output, "lipo", inputs, variables=extra_bindings)
+            return output
+
+    def WriteLinkForArch(
+        self, ninja_file, spec, config_name, config, link_deps, compile_deps, arch=None
+    ):
+        """Write out a link step. Fills out target.binary. """
+        command = {
+            "executable": "link",
+            "loadable_module": "solink_module",
+            "shared_library": "solink",
+        }[spec["type"]]
+        command_suffix = ""
+
+        implicit_deps = set()
+        solibs = set()
+        order_deps = set()
+
+        if compile_deps:
+            # Normally, the compiles of the target already depend on compile_deps,
+            # but a shared_library target might have no sources and only link together
+            # a few static_library deps, so the link step also needs to depend
+            # on compile_deps to make sure actions in the shared_library target
+            # get run before the link.
+            order_deps.add(compile_deps)
+
+        if "dependencies" in spec:
+            # Two kinds of dependencies:
+            # - Linkable dependencies (like a .a or a .so): add them to the link line.
+            # - Non-linkable dependencies (like a rule that generates a file
+            #   and writes a stamp file): add them to implicit_deps
+            extra_link_deps = set()
+            for dep in spec["dependencies"]:
+                target = self.target_outputs.get(dep)
+                if not target:
+                    continue
+                linkable = target.Linkable()
+                if linkable:
+                    new_deps = []
+                    if (
+                        self.flavor == "win"
+                        and target.component_objs
+                        and self.msvs_settings.IsUseLibraryDependencyInputs(config_name)
+                    ):
+                        new_deps = target.component_objs
+                        if target.compile_deps:
+                            order_deps.add(target.compile_deps)
+                    elif self.flavor == "win" and target.import_lib:
+                        new_deps = [target.import_lib]
+                    elif target.UsesToc(self.flavor):
+                        solibs.add(target.binary)
+                        implicit_deps.add(target.binary + ".TOC")
+                    else:
+                        new_deps = [target.binary]
+                    for new_dep in new_deps:
+                        if new_dep not in extra_link_deps:
+                            extra_link_deps.add(new_dep)
+                            link_deps.append(new_dep)
+
+                final_output = target.FinalOutput()
+                if not linkable or final_output != target.binary:
+                    implicit_deps.add(final_output)
+
+        extra_bindings = []
+        if self.target.uses_cpp and self.flavor != "win":
+            extra_bindings.append(("ld", "$ldxx"))
+
+        output = self.ComputeOutput(spec, arch)
+        if arch is None and not self.is_mac_bundle:
+            self.AppendPostbuildVariable(extra_bindings, spec, output, output)
+
+        is_executable = spec["type"] == "executable"
+        # The ldflags config key is not used on mac or win. On those platforms
+        # linker flags are set via xcode_settings and msvs_settings, respectively.
+        if self.toolset == "target":
+            env_ldflags = os.environ.get("LDFLAGS", "").split()
+        elif self.toolset == "host":
+            env_ldflags = os.environ.get("LDFLAGS_host", "").split()
+
+        if self.flavor == "mac":
+            ldflags = self.xcode_settings.GetLdflags(
+                config_name,
+                self.ExpandSpecial(generator_default_variables["PRODUCT_DIR"]),
+                self.GypPathToNinja,
+                arch,
+            )
+            ldflags = env_ldflags + ldflags
+        elif self.flavor == "win":
+            manifest_base_name = self.GypPathToUniqueOutput(
+                self.ComputeOutputFileName(spec)
+            )
+            (
+                ldflags,
+                intermediate_manifest,
+                manifest_files,
+            ) = self.msvs_settings.GetLdflags(
+                config_name,
+                self.GypPathToNinja,
+                self.ExpandSpecial,
+                manifest_base_name,
+                output,
+                is_executable,
+                self.toplevel_build,
+            )
+            ldflags = env_ldflags + ldflags
+            self.WriteVariableList(ninja_file, "manifests", manifest_files)
+            implicit_deps = implicit_deps.union(manifest_files)
+            if intermediate_manifest:
+                self.WriteVariableList(
+                    ninja_file, "intermediatemanifest", [intermediate_manifest]
+                )
+            command_suffix = _GetWinLinkRuleNameSuffix(
+                self.msvs_settings.IsEmbedManifest(config_name)
+            )
+            def_file = self.msvs_settings.GetDefFile(self.GypPathToNinja)
+            if def_file:
+                implicit_deps.add(def_file)
+        else:
+            # Respect environment variables related to build, but target-specific
+            # flags can still override them.
+            ldflags = env_ldflags + config.get("ldflags", [])
+            if is_executable and len(solibs):
+                rpath = "lib/"
+                if self.toolset != "target":
+                    rpath += self.toolset
+                    ldflags.append(r"-Wl,-rpath=\$$ORIGIN/%s" % rpath)
+                else:
+                    ldflags.append("-Wl,-rpath=%s" % self.target_rpath)
+                ldflags.append("-Wl,-rpath-link=%s" % rpath)
+        self.WriteVariableList(ninja_file, "ldflags", map(self.ExpandSpecial, ldflags))
+
+        library_dirs = config.get("library_dirs", [])
+        if self.flavor == "win":
+            library_dirs = [
+                self.msvs_settings.ConvertVSMacros(library_dir, config_name)
+                for library_dir in library_dirs
+            ]
+            library_dirs = [
+                "/LIBPATH:"
+                + QuoteShellArgument(self.GypPathToNinja(library_dir), self.flavor)
+                for library_dir in library_dirs
+            ]
+        else:
+            library_dirs = [
+                QuoteShellArgument("-L" + self.GypPathToNinja(library_dir), self.flavor)
+                for library_dir in library_dirs
+            ]
+
+        libraries = gyp.common.uniquer(
+            map(self.ExpandSpecial, spec.get("libraries", []))
+        )
+        if self.flavor == "mac":
+            libraries = self.xcode_settings.AdjustLibraries(libraries, config_name)
+        elif self.flavor == "win":
+            libraries = self.msvs_settings.AdjustLibraries(libraries)
+
+        self.WriteVariableList(ninja_file, "libs", library_dirs + libraries)
+
+        linked_binary = output
+
+        if command in ("solink", "solink_module"):
+            extra_bindings.append(("soname", os.path.split(output)[1]))
+            extra_bindings.append(("lib", gyp.common.EncodePOSIXShellArgument(output)))
+            if self.flavor != "win":
+                link_file_list = output
+                if self.is_mac_bundle:
+                    # 'Dependency Framework.framework/Versions/A/Dependency Framework'
+                    # -> 'Dependency Framework.framework.rsp'
+                    link_file_list = self.xcode_settings.GetWrapperName()
+                if arch:
+                    link_file_list += "." + arch
+                link_file_list += ".rsp"
+                # If an rspfile contains spaces, ninja surrounds the filename with
+                # quotes around it and then passes it to open(), creating a file with
+                # quotes in its name (and when looking for the rsp file, the name
+                # makes it through bash which strips the quotes) :-/
+                link_file_list = link_file_list.replace(" ", "_")
+                extra_bindings.append(
+                    (
+                        "link_file_list",
+                        gyp.common.EncodePOSIXShellArgument(link_file_list),
+                    )
+                )
+            if self.flavor == "win":
+                extra_bindings.append(("binary", output))
+                if (
+                    "/NOENTRY" not in ldflags
+                    and not self.msvs_settings.GetNoImportLibrary(config_name)
+                ):
+                    self.target.import_lib = output + ".lib"
+                    extra_bindings.append(
+                        ("implibflag", "/IMPLIB:%s" % self.target.import_lib)
+                    )
+                    pdbname = self.msvs_settings.GetPDBName(
+                        config_name, self.ExpandSpecial, output + ".pdb"
+                    )
+                    output = [output, self.target.import_lib]
+                    if pdbname:
+                        output.append(pdbname)
+            elif not self.is_mac_bundle:
+                output = [output, output + ".TOC"]
+            else:
+                command = command + "_notoc"
+        elif self.flavor == "win":
+            extra_bindings.append(("binary", output))
+            pdbname = self.msvs_settings.GetPDBName(
+                config_name, self.ExpandSpecial, output + ".pdb"
+            )
+            if pdbname:
+                output = [output, pdbname]
+
+        if len(solibs):
+            extra_bindings.append(
+                ("solibs", gyp.common.EncodePOSIXShellList(sorted(solibs)))
+            )
+
+        ninja_file.build(
+            output,
+            command + command_suffix,
+            link_deps,
+            implicit=sorted(implicit_deps),
+            order_only=list(order_deps),
+            variables=extra_bindings,
+        )
+        return linked_binary
+
+    def WriteTarget(self, spec, config_name, config, link_deps, compile_deps):
+        extra_link_deps = any(
+            self.target_outputs.get(dep).Linkable()
+            for dep in spec.get("dependencies", [])
+            if dep in self.target_outputs
+        )
+        if spec["type"] == "none" or (not link_deps and not extra_link_deps):
+            # TODO(evan): don't call this function for 'none' target types, as
+            # it doesn't do anything, and we fake out a 'binary' with a stamp file.
+            self.target.binary = compile_deps
+            self.target.type = "none"
+        elif spec["type"] == "static_library":
+            self.target.binary = self.ComputeOutput(spec)
+            if (
+                self.flavor not in ("mac", "openbsd", "netbsd", "win")
+                and not self.is_standalone_static_library
+            ):
+                self.ninja.build(
+                    self.target.binary, "alink_thin", link_deps, order_only=compile_deps
+                )
+            else:
+                variables = []
+                if self.xcode_settings:
+                    libtool_flags = self.xcode_settings.GetLibtoolflags(config_name)
+                    if libtool_flags:
+                        variables.append(("libtool_flags", libtool_flags))
+                if self.msvs_settings:
+                    libflags = self.msvs_settings.GetLibFlags(
+                        config_name, self.GypPathToNinja
+                    )
+                    variables.append(("libflags", libflags))
+
+                if self.flavor != "mac" or len(self.archs) == 1:
+                    self.AppendPostbuildVariable(
+                        variables, spec, self.target.binary, self.target.binary
+                    )
+                    self.ninja.build(
+                        self.target.binary,
+                        "alink",
+                        link_deps,
+                        order_only=compile_deps,
+                        variables=variables,
+                    )
+                else:
+                    inputs = []
+                    for arch in self.archs:
+                        output = self.ComputeOutput(spec, arch)
+                        self.arch_subninjas[arch].build(
+                            output,
+                            "alink",
+                            link_deps[arch],
+                            order_only=compile_deps,
+                            variables=variables,
+                        )
+                        inputs.append(output)
+                    # TODO: It's not clear if
+                    # libtool_flags should be passed to the alink
+                    # call that combines single-arch .a files into a fat .a file.
+                    self.AppendPostbuildVariable(
+                        variables, spec, self.target.binary, self.target.binary
+                    )
+                    self.ninja.build(
+                        self.target.binary,
+                        "alink",
+                        inputs,
+                        # FIXME: test proving order_only=compile_deps isn't
+                        # needed.
+                        variables=variables,
+                    )
+        else:
+            self.target.binary = self.WriteLink(
+                spec, config_name, config, link_deps, compile_deps
+            )
+        return self.target.binary
+
+    def WriteMacBundle(self, spec, mac_bundle_depends, is_empty):
+        assert self.is_mac_bundle
+        package_framework = spec["type"] in ("shared_library", "loadable_module")
+        output = self.ComputeMacBundleOutput()
+        if is_empty:
+            output += ".stamp"
+        variables = []
+        self.AppendPostbuildVariable(
+            variables,
+            spec,
+            output,
+            self.target.binary,
+            is_command_start=not package_framework,
+        )
+        if package_framework and not is_empty:
+            if spec["type"] == "shared_library" and self.xcode_settings.isIOS:
+                self.ninja.build(
+                    output,
+                    "package_ios_framework",
+                    mac_bundle_depends,
+                    variables=variables,
+                )
+            else:
+                variables.append(("version", self.xcode_settings.GetFrameworkVersion()))
+                self.ninja.build(
+                    output, "package_framework", mac_bundle_depends, variables=variables
+                )
+        else:
+            self.ninja.build(output, "stamp", mac_bundle_depends, variables=variables)
+        self.target.bundle = output
+        return output
+
+    def GetToolchainEnv(self, additional_settings=None):
+        """Returns the variables toolchain would set for build steps."""
+        env = self.GetSortedXcodeEnv(additional_settings=additional_settings)
+        if self.flavor == "win":
+            env = self.GetMsvsToolchainEnv(additional_settings=additional_settings)
+        return env
+
+    def GetMsvsToolchainEnv(self, additional_settings=None):
+        """Returns the variables Visual Studio would set for build steps."""
+        return self.msvs_settings.GetVSMacroEnv(
+            "$!PRODUCT_DIR", config=self.config_name
+        )
+
+    def GetSortedXcodeEnv(self, additional_settings=None):
+        """Returns the variables Xcode would set for build steps."""
+        assert self.abs_build_dir
+        abs_build_dir = self.abs_build_dir
+        return gyp.xcode_emulation.GetSortedXcodeEnv(
+            self.xcode_settings,
+            abs_build_dir,
+            os.path.join(abs_build_dir, self.build_to_base),
+            self.config_name,
+            additional_settings,
+        )
+
+    def GetSortedXcodePostbuildEnv(self):
+        """Returns the variables Xcode would set for postbuild steps."""
+        postbuild_settings = {}
+        # CHROMIUM_STRIP_SAVE_FILE is a chromium-specific hack.
+        # TODO(thakis): It would be nice to have some general mechanism instead.
+        strip_save_file = self.xcode_settings.GetPerTargetSetting(
+            "CHROMIUM_STRIP_SAVE_FILE"
+        )
+        if strip_save_file:
+            postbuild_settings["CHROMIUM_STRIP_SAVE_FILE"] = strip_save_file
+        return self.GetSortedXcodeEnv(additional_settings=postbuild_settings)
+
+    def AppendPostbuildVariable(
+        self, variables, spec, output, binary, is_command_start=False
+    ):
+        """Adds a 'postbuild' variable if there is a postbuild for |output|."""
+        postbuild = self.GetPostbuildCommand(spec, output, binary, is_command_start)
+        if postbuild:
+            variables.append(("postbuilds", postbuild))
+
+    def GetPostbuildCommand(self, spec, output, output_binary, is_command_start):
+        """Returns a shell command that runs all the postbuilds, and removes
+        |output| if any of them fails. If |is_command_start| is False, then the
+        returned string will start with ' && '."""
+        if not self.xcode_settings or spec["type"] == "none" or not output:
+            return ""
+        output = QuoteShellArgument(output, self.flavor)
+        postbuilds = gyp.xcode_emulation.GetSpecPostbuildCommands(spec, quiet=True)
+        if output_binary is not None:
+            postbuilds = self.xcode_settings.AddImplicitPostbuilds(
+                self.config_name,
+                os.path.normpath(os.path.join(self.base_to_build, output)),
+                QuoteShellArgument(
+                    os.path.normpath(os.path.join(self.base_to_build, output_binary)),
+                    self.flavor,
+                ),
+                postbuilds,
+                quiet=True,
+            )
+
+        if not postbuilds:
+            return ""
+        # Postbuilds expect to be run in the gyp file's directory, so insert an
+        # implicit postbuild to cd to there.
+        postbuilds.insert(
+            0, gyp.common.EncodePOSIXShellList(["cd", self.build_to_base])
+        )
+        env = self.ComputeExportEnvString(self.GetSortedXcodePostbuildEnv())
+        # G will be non-null if any postbuild fails. Run all postbuilds in a
+        # subshell.
+        commands = (
+            env
+            + " ("
+            + " && ".join([ninja_syntax.escape(command) for command in postbuilds])
+        )
+        command_string = (
+            commands
+            + "); G=$$?; "
+            # Remove the final output if any postbuild failed.
+            "((exit $$G) || rm -rf %s) " % output
+            + "&& exit $$G)"
+        )
+        if is_command_start:
+            return "(" + command_string + " && "
+        else:
+            return "$ && (" + command_string
+
+    def ComputeExportEnvString(self, env):
+        """Given an environment, returns a string looking like
+            'export FOO=foo; export BAR="${FOO} bar;'
+        that exports |env| to the shell."""
+        export_str = []
+        for k, v in env:
+            export_str.append(
+                "export %s=%s;"
+                % (k, ninja_syntax.escape(gyp.common.EncodePOSIXShellArgument(v)))
+            )
+        return " ".join(export_str)
+
+    def ComputeMacBundleOutput(self):
+        """Return the 'output' (full output path) to a bundle output directory."""
+        assert self.is_mac_bundle
+        path = generator_default_variables["PRODUCT_DIR"]
+        return self.ExpandSpecial(
+            os.path.join(path, self.xcode_settings.GetWrapperName())
+        )
+
+    def ComputeOutputFileName(self, spec, type=None):
+        """Compute the filename of the final output for the current target."""
+        if not type:
+            type = spec["type"]
+
+        default_variables = copy.copy(generator_default_variables)
+        CalculateVariables(default_variables, {"flavor": self.flavor})
+
+        # Compute filename prefix: the product prefix, or a default for
+        # the product type.
+        DEFAULT_PREFIX = {
+            "loadable_module": default_variables["SHARED_LIB_PREFIX"],
+            "shared_library": default_variables["SHARED_LIB_PREFIX"],
+            "static_library": default_variables["STATIC_LIB_PREFIX"],
+            "executable": default_variables["EXECUTABLE_PREFIX"],
+        }
+        prefix = spec.get("product_prefix", DEFAULT_PREFIX.get(type, ""))
+
+        # Compute filename extension: the product extension, or a default
+        # for the product type.
+        DEFAULT_EXTENSION = {
+            "loadable_module": default_variables["SHARED_LIB_SUFFIX"],
+            "shared_library": default_variables["SHARED_LIB_SUFFIX"],
+            "static_library": default_variables["STATIC_LIB_SUFFIX"],
+            "executable": default_variables["EXECUTABLE_SUFFIX"],
+        }
+        extension = spec.get("product_extension")
+        if extension:
+            extension = "." + extension
+        else:
+            extension = DEFAULT_EXTENSION.get(type, "")
+
+        if "product_name" in spec:
+            # If we were given an explicit name, use that.
+            target = spec["product_name"]
+        else:
+            # Otherwise, derive a name from the target name.
+            target = spec["target_name"]
+            if prefix == "lib":
+                # Snip out an extra 'lib' from libs if appropriate.
+                target = StripPrefix(target, "lib")
+
+        if type in (
+            "static_library",
+            "loadable_module",
+            "shared_library",
+            "executable",
+        ):
+            return f"{prefix}{target}{extension}"
+        elif type == "none":
+            return "%s.stamp" % target
+        else:
+            raise Exception("Unhandled output type %s" % type)
+
+    def ComputeOutput(self, spec, arch=None):
+        """Compute the path for the final output of the spec."""
+        type = spec["type"]
+
+        if self.flavor == "win":
+            override = self.msvs_settings.GetOutputName(
+                self.config_name, self.ExpandSpecial
+            )
+            if override:
+                return override
+
+        if (
+            arch is None
+            and self.flavor == "mac"
+            and type
+            in ("static_library", "executable", "shared_library", "loadable_module")
+        ):
+            filename = self.xcode_settings.GetExecutablePath()
+        else:
+            filename = self.ComputeOutputFileName(spec, type)
+
+        if arch is None and "product_dir" in spec:
+            path = os.path.join(spec["product_dir"], filename)
+            return self.ExpandSpecial(path)
+
+        # Some products go into the output root, libraries go into shared library
+        # dir, and everything else goes into the normal place.
+        type_in_output_root = ["executable", "loadable_module"]
+        if self.flavor == "mac" and self.toolset == "target":
+            type_in_output_root += ["shared_library", "static_library"]
+        elif self.flavor == "win" and self.toolset == "target":
+            type_in_output_root += ["shared_library"]
+
+        if arch is not None:
+            # Make sure partial executables don't end up in a bundle or the regular
+            # output directory.
+            archdir = "arch"
+            if self.toolset != "target":
+                archdir = os.path.join("arch", "%s" % self.toolset)
+            return os.path.join(archdir, AddArch(filename, arch))
+        elif type in type_in_output_root or self.is_standalone_static_library:
+            return filename
+        elif type == "shared_library":
+            libdir = "lib"
+            if self.toolset != "target":
+                libdir = os.path.join("lib", "%s" % self.toolset)
+            return os.path.join(libdir, filename)
+        else:
+            return self.GypPathToUniqueOutput(filename, qualified=False)
+
+    def WriteVariableList(self, ninja_file, var, values):
+        assert not isinstance(values, str)
+        if values is None:
+            values = []
+        ninja_file.variable(var, " ".join(values))
+
+    def WriteNewNinjaRule(
+        self, name, args, description, win_shell_flags, env, pool, depfile=None
+    ):
+        """Write out a new ninja "rule" statement for a given command.
+
+        Returns the name of the new rule, and a copy of |args| with variables
+        expanded."""
+
+        if self.flavor == "win":
+            args = [
+                self.msvs_settings.ConvertVSMacros(
+                    arg, self.base_to_build, config=self.config_name
+                )
+                for arg in args
+            ]
+            description = self.msvs_settings.ConvertVSMacros(
+                description, config=self.config_name
+            )
+        elif self.flavor == "mac":
+            # |env| is an empty list on non-mac.
+            args = [gyp.xcode_emulation.ExpandEnvVars(arg, env) for arg in args]
+            description = gyp.xcode_emulation.ExpandEnvVars(description, env)
+
+        # TODO: we shouldn't need to qualify names; we do it because
+        # currently the ninja rule namespace is global, but it really
+        # should be scoped to the subninja.
+        rule_name = self.name
+        if self.toolset == "target":
+            rule_name += "." + self.toolset
+        rule_name += "." + name
+        rule_name = re.sub("[^a-zA-Z0-9_]", "_", rule_name)
+
+        # Remove variable references, but not if they refer to the magic rule
+        # variables.  This is not quite right, as it also protects these for
+        # actions, not just for rules where they are valid. Good enough.
+        protect = ["${root}", "${dirname}", "${source}", "${ext}", "${name}"]
+        protect = "(?!" + "|".join(map(re.escape, protect)) + ")"
+        description = re.sub(protect + r"\$", "_", description)
+
+        # gyp dictates that commands are run from the base directory.
+        # cd into the directory before running, and adjust paths in
+        # the arguments to point to the proper locations.
+        rspfile = None
+        rspfile_content = None
+        args = [self.ExpandSpecial(arg, self.base_to_build) for arg in args]
+        if self.flavor == "win":
+            rspfile = rule_name + ".$unique_name.rsp"
+            # The cygwin case handles this inside the bash sub-shell.
+            run_in = "" if win_shell_flags.cygwin else " " + self.build_to_base
+            if win_shell_flags.cygwin:
+                rspfile_content = self.msvs_settings.BuildCygwinBashCommandLine(
+                    args, self.build_to_base
+                )
+            else:
+                rspfile_content = gyp.msvs_emulation.EncodeRspFileList(
+                    args, win_shell_flags.quote)
+            command = (
+                "%s gyp-win-tool action-wrapper $arch " % sys.executable
+                + rspfile
+                + run_in
+            )
+        else:
+            env = self.ComputeExportEnvString(env)
+            command = gyp.common.EncodePOSIXShellList(args)
+            command = "cd %s; " % self.build_to_base + env + command
+
+        # GYP rules/actions express being no-ops by not touching their outputs.
+        # Avoid executing downstream dependencies in this case by specifying
+        # restat=1 to ninja.
+        self.ninja.rule(
+            rule_name,
+            command,
+            description,
+            depfile=depfile,
+            restat=True,
+            pool=pool,
+            rspfile=rspfile,
+            rspfile_content=rspfile_content,
+        )
+        self.ninja.newline()
+
+        return rule_name, args
+
+
+def CalculateVariables(default_variables, params):
+    """Calculate additional variables for use in the build (called by gyp)."""
+    global generator_additional_non_configuration_keys
+    global generator_additional_path_sections
+    flavor = gyp.common.GetFlavor(params)
+    if flavor == "mac":
+        default_variables.setdefault("OS", "mac")
+        default_variables.setdefault("SHARED_LIB_SUFFIX", ".dylib")
+        default_variables.setdefault(
+            "SHARED_LIB_DIR", generator_default_variables["PRODUCT_DIR"]
+        )
+        default_variables.setdefault(
+            "LIB_DIR", generator_default_variables["PRODUCT_DIR"]
+        )
+
+        # Copy additional generator configuration data from Xcode, which is shared
+        # by the Mac Ninja generator.
+        import gyp.generator.xcode as xcode_generator
+
+        generator_additional_non_configuration_keys = getattr(
+            xcode_generator, "generator_additional_non_configuration_keys", []
+        )
+        generator_additional_path_sections = getattr(
+            xcode_generator, "generator_additional_path_sections", []
+        )
+        global generator_extra_sources_for_rules
+        generator_extra_sources_for_rules = getattr(
+            xcode_generator, "generator_extra_sources_for_rules", []
+        )
+    elif flavor == "win":
+        exts = gyp.MSVSUtil.TARGET_TYPE_EXT
+        default_variables.setdefault("OS", "win")
+        default_variables["EXECUTABLE_SUFFIX"] = "." + exts["executable"]
+        default_variables["STATIC_LIB_PREFIX"] = ""
+        default_variables["STATIC_LIB_SUFFIX"] = "." + exts["static_library"]
+        default_variables["SHARED_LIB_PREFIX"] = ""
+        default_variables["SHARED_LIB_SUFFIX"] = "." + exts["shared_library"]
+
+        # Copy additional generator configuration data from VS, which is shared
+        # by the Windows Ninja generator.
+        import gyp.generator.msvs as msvs_generator
+
+        generator_additional_non_configuration_keys = getattr(
+            msvs_generator, "generator_additional_non_configuration_keys", []
+        )
+        generator_additional_path_sections = getattr(
+            msvs_generator, "generator_additional_path_sections", []
+        )
+
+        gyp.msvs_emulation.CalculateCommonVariables(default_variables, params)
+    else:
+        operating_system = flavor
+        if flavor == "android":
+            operating_system = "linux"  # Keep this legacy behavior for now.
+        default_variables.setdefault("OS", operating_system)
+        default_variables.setdefault("SHARED_LIB_SUFFIX", ".so")
+        default_variables.setdefault(
+            "SHARED_LIB_DIR", os.path.join("$!PRODUCT_DIR", "lib")
+        )
+        default_variables.setdefault("LIB_DIR", os.path.join("$!PRODUCT_DIR", "obj"))
+
+
+def ComputeOutputDir(params):
+    """Returns the path from the toplevel_dir to the build output directory."""
+    # generator_dir: relative path from pwd to where make puts build files.
+    # Makes migrating from make to ninja easier, ninja doesn't put anything here.
+    generator_dir = os.path.relpath(params["options"].generator_output or ".")
+
+    # output_dir: relative path from generator_dir to the build directory.
+    output_dir = params.get("generator_flags", {}).get("output_dir", "out")
+
+    # Relative path from source root to our output files.  e.g. "out"
+    return os.path.normpath(os.path.join(generator_dir, output_dir))
+
+
+def CalculateGeneratorInputInfo(params):
+    """Called by __init__ to initialize generator values based on params."""
+    # E.g. "out/gypfiles"
+    toplevel = params["options"].toplevel_dir
+    qualified_out_dir = os.path.normpath(
+        os.path.join(toplevel, ComputeOutputDir(params), "gypfiles")
+    )
+
+    global generator_filelist_paths
+    generator_filelist_paths = {
+        "toplevel": toplevel,
+        "qualified_out_dir": qualified_out_dir,
+    }
+
+
+def OpenOutput(path, mode="w"):
+    """Open |path| for writing, creating directories if necessary."""
+    gyp.common.EnsureDirExists(path)
+    return open(path, mode)
+
+
+def CommandWithWrapper(cmd, wrappers, prog):
+    wrapper = wrappers.get(cmd, "")
+    if wrapper:
+        return wrapper + " " + prog
+    return prog
+
+
+def GetDefaultConcurrentLinks():
+    """Returns a best-guess for a number of concurrent links."""
+    pool_size = int(os.environ.get("GYP_LINK_CONCURRENCY", 0))
+    if pool_size:
+        return pool_size
+
+    if sys.platform in ("win32", "cygwin"):
+        import ctypes
+
+        class MEMORYSTATUSEX(ctypes.Structure):
+            _fields_ = [
+                ("dwLength", ctypes.c_ulong),
+                ("dwMemoryLoad", ctypes.c_ulong),
+                ("ullTotalPhys", ctypes.c_ulonglong),
+                ("ullAvailPhys", ctypes.c_ulonglong),
+                ("ullTotalPageFile", ctypes.c_ulonglong),
+                ("ullAvailPageFile", ctypes.c_ulonglong),
+                ("ullTotalVirtual", ctypes.c_ulonglong),
+                ("ullAvailVirtual", ctypes.c_ulonglong),
+                ("sullAvailExtendedVirtual", ctypes.c_ulonglong),
+            ]
+
+        stat = MEMORYSTATUSEX()
+        stat.dwLength = ctypes.sizeof(stat)
+        ctypes.windll.kernel32.GlobalMemoryStatusEx(ctypes.byref(stat))
+
+        # VS 2015 uses 20% more working set than VS 2013 and can consume all RAM
+        # on a 64 GB machine.
+        mem_limit = max(1, stat.ullTotalPhys // (5 * (2 ** 30)))  # total / 5GB
+        hard_cap = max(1, int(os.environ.get("GYP_LINK_CONCURRENCY_MAX", 2 ** 32)))
+        return min(mem_limit, hard_cap)
+    elif sys.platform.startswith("linux"):
+        if os.path.exists("/proc/meminfo"):
+            with open("/proc/meminfo") as meminfo:
+                memtotal_re = re.compile(r"^MemTotal:\s*(\d*)\s*kB")
+                for line in meminfo:
+                    match = memtotal_re.match(line)
+                    if not match:
+                        continue
+                    # Allow 8Gb per link on Linux because Gold is quite memory hungry
+                    return max(1, int(match.group(1)) // (8 * (2 ** 20)))
+        return 1
+    elif sys.platform == "darwin":
+        try:
+            avail_bytes = int(subprocess.check_output(["sysctl", "-n", "hw.memsize"]))
+            # A static library debug build of Chromium's unit_tests takes ~2.7GB, so
+            # 4GB per ld process allows for some more bloat.
+            return max(1, avail_bytes // (4 * (2 ** 30)))  # total / 4GB
+        except subprocess.CalledProcessError:
+            return 1
+    else:
+        # TODO(scottmg): Implement this for other platforms.
+        return 1
+
+
+def _GetWinLinkRuleNameSuffix(embed_manifest):
+    """Returns the suffix used to select an appropriate linking rule depending on
+    whether the manifest embedding is enabled."""
+    return "_embed" if embed_manifest else ""
+
+
+def _AddWinLinkRules(master_ninja, embed_manifest):
+    """Adds link rules for Windows platform to |master_ninja|."""
+
+    def FullLinkCommand(ldcmd, out, binary_type):
+        resource_name = {"exe": "1", "dll": "2"}[binary_type]
+        return (
+            "%(python)s gyp-win-tool link-with-manifests $arch %(embed)s "
+            '%(out)s "%(ldcmd)s" %(resname)s $mt $rc "$intermediatemanifest" '
+            "$manifests"
+            % {
+                "python": sys.executable,
+                "out": out,
+                "ldcmd": ldcmd,
+                "resname": resource_name,
+                "embed": embed_manifest,
+            }
+        )
+
+    rule_name_suffix = _GetWinLinkRuleNameSuffix(embed_manifest)
+    use_separate_mspdbsrv = int(os.environ.get("GYP_USE_SEPARATE_MSPDBSRV", "0")) != 0
+    dlldesc = "LINK%s(DLL) $binary" % rule_name_suffix.upper()
+    dllcmd = (
+        "%s gyp-win-tool link-wrapper $arch %s "
+        "$ld /nologo $implibflag /DLL /OUT:$binary "
+        "@$binary.rsp" % (sys.executable, use_separate_mspdbsrv)
+    )
+    dllcmd = FullLinkCommand(dllcmd, "$binary", "dll")
+    master_ninja.rule(
+        "solink" + rule_name_suffix,
+        description=dlldesc,
+        command=dllcmd,
+        rspfile="$binary.rsp",
+        rspfile_content="$libs $in_newline $ldflags",
+        restat=True,
+        pool="link_pool",
+    )
+    master_ninja.rule(
+        "solink_module" + rule_name_suffix,
+        description=dlldesc,
+        command=dllcmd,
+        rspfile="$binary.rsp",
+        rspfile_content="$libs $in_newline $ldflags",
+        restat=True,
+        pool="link_pool",
+    )
+    # Note that ldflags goes at the end so that it has the option of
+    # overriding default settings earlier in the command line.
+    exe_cmd = (
+        "%s gyp-win-tool link-wrapper $arch %s "
+        "$ld /nologo /OUT:$binary @$binary.rsp"
+        % (sys.executable, use_separate_mspdbsrv)
+    )
+    exe_cmd = FullLinkCommand(exe_cmd, "$binary", "exe")
+    master_ninja.rule(
+        "link" + rule_name_suffix,
+        description="LINK%s $binary" % rule_name_suffix.upper(),
+        command=exe_cmd,
+        rspfile="$binary.rsp",
+        rspfile_content="$in_newline $libs $ldflags",
+        pool="link_pool",
+    )
+
+
+def GenerateOutputForConfig(target_list, target_dicts, data, params, config_name):
+    options = params["options"]
+    flavor = gyp.common.GetFlavor(params)
+    generator_flags = params.get("generator_flags", {})
+
+    # build_dir: relative path from source root to our output files.
+    # e.g. "out/Debug"
+    build_dir = os.path.normpath(os.path.join(ComputeOutputDir(params), config_name))
+
+    toplevel_build = os.path.join(options.toplevel_dir, build_dir)
+
+    master_ninja_file = OpenOutput(os.path.join(toplevel_build, "build.ninja"))
+    master_ninja = ninja_syntax.Writer(master_ninja_file, width=120)
+
+    # Put build-time support tools in out/{config_name}.
+    gyp.common.CopyTool(flavor, toplevel_build, generator_flags)
+
+    # Grab make settings for CC/CXX.
+    # The rules are
+    # - The priority from low to high is gcc/g++, the 'make_global_settings' in
+    #   gyp, the environment variable.
+    # - If there is no 'make_global_settings' for CC.host/CXX.host or
+    #   'CC_host'/'CXX_host' environment variable, cc_host/cxx_host should be set
+    #   to cc/cxx.
+    if flavor == "win":
+        ar = "lib.exe"
+        # cc and cxx must be set to the correct architecture by overriding with one
+        # of cl_x86 or cl_x64 below.
+        cc = "UNSET"
+        cxx = "UNSET"
+        ld = "link.exe"
+        ld_host = "$ld"
+    else:
+        ar = "ar"
+        cc = "cc"
+        cxx = "c++"
+        ld = "$cc"
+        ldxx = "$cxx"
+        ld_host = "$cc_host"
+        ldxx_host = "$cxx_host"
+
+    ar_host = ar
+    cc_host = None
+    cxx_host = None
+    cc_host_global_setting = None
+    cxx_host_global_setting = None
+    clang_cl = None
+    nm = "nm"
+    nm_host = "nm"
+    readelf = "readelf"
+    readelf_host = "readelf"
+
+    build_file, _, _ = gyp.common.ParseQualifiedTarget(target_list[0])
+    make_global_settings = data[build_file].get("make_global_settings", [])
+    build_to_root = gyp.common.InvertRelativePath(build_dir, options.toplevel_dir)
+    wrappers = {}
+    for key, value in make_global_settings:
+        if key == "AR":
+            ar = os.path.join(build_to_root, value)
+        if key == "AR.host":
+            ar_host = os.path.join(build_to_root, value)
+        if key == "CC":
+            cc = os.path.join(build_to_root, value)
+            if cc.endswith("clang-cl"):
+                clang_cl = cc
+        if key == "CXX":
+            cxx = os.path.join(build_to_root, value)
+        if key == "CC.host":
+            cc_host = os.path.join(build_to_root, value)
+            cc_host_global_setting = value
+        if key == "CXX.host":
+            cxx_host = os.path.join(build_to_root, value)
+            cxx_host_global_setting = value
+        if key == "LD":
+            ld = os.path.join(build_to_root, value)
+        if key == "LD.host":
+            ld_host = os.path.join(build_to_root, value)
+        if key == "LDXX":
+            ldxx = os.path.join(build_to_root, value)
+        if key == "LDXX.host":
+            ldxx_host = os.path.join(build_to_root, value)
+        if key == "NM":
+            nm = os.path.join(build_to_root, value)
+        if key == "NM.host":
+            nm_host = os.path.join(build_to_root, value)
+        if key == "READELF":
+            readelf = os.path.join(build_to_root, value)
+        if key == "READELF.host":
+            readelf_host = os.path.join(build_to_root, value)
+        if key.endswith("_wrapper"):
+            wrappers[key[: -len("_wrapper")]] = os.path.join(build_to_root, value)
+
+    # Support wrappers from environment variables too.
+    for key, value in os.environ.items():
+        if key.lower().endswith("_wrapper"):
+            key_prefix = key[: -len("_wrapper")]
+            key_prefix = re.sub(r"\.HOST$", ".host", key_prefix)
+            wrappers[key_prefix] = os.path.join(build_to_root, value)
+
+    mac_toolchain_dir = generator_flags.get("mac_toolchain_dir", None)
+    if mac_toolchain_dir:
+        wrappers["LINK"] = "export DEVELOPER_DIR='%s' &&" % mac_toolchain_dir
+
+    if flavor == "win":
+        configs = [
+            target_dicts[qualified_target]["configurations"][config_name]
+            for qualified_target in target_list
+        ]
+        shared_system_includes = None
+        if not generator_flags.get("ninja_use_custom_environment_files", 0):
+            shared_system_includes = gyp.msvs_emulation.ExtractSharedMSVSSystemIncludes(
+                configs, generator_flags
+            )
+        cl_paths = gyp.msvs_emulation.GenerateEnvironmentFiles(
+            toplevel_build, generator_flags, shared_system_includes, OpenOutput
+        )
+        for arch, path in sorted(cl_paths.items()):
+            if clang_cl:
+                # If we have selected clang-cl, use that instead.
+                path = clang_cl
+            command = CommandWithWrapper(
+                "CC", wrappers, QuoteShellArgument(path, "win")
+            )
+            if clang_cl:
+                # Use clang-cl to cross-compile for x86 or x86_64.
+                command += " -m32" if arch == "x86" else " -m64"
+            master_ninja.variable("cl_" + arch, command)
+
+    cc = GetEnvironFallback(["CC_target", "CC"], cc)
+    master_ninja.variable("cc", CommandWithWrapper("CC", wrappers, cc))
+    cxx = GetEnvironFallback(["CXX_target", "CXX"], cxx)
+    master_ninja.variable("cxx", CommandWithWrapper("CXX", wrappers, cxx))
+
+    if flavor == "win":
+        master_ninja.variable("ld", ld)
+        master_ninja.variable("idl", "midl.exe")
+        master_ninja.variable("ar", ar)
+        master_ninja.variable("rc", "rc.exe")
+        master_ninja.variable("ml_x86", "ml.exe")
+        master_ninja.variable("ml_x64", "ml64.exe")
+        master_ninja.variable("mt", "mt.exe")
+    else:
+        master_ninja.variable("ld", CommandWithWrapper("LINK", wrappers, ld))
+        master_ninja.variable("ldxx", CommandWithWrapper("LINK", wrappers, ldxx))
+        master_ninja.variable("ar", GetEnvironFallback(["AR_target", "AR"], ar))
+        if flavor != "mac":
+            # Mac does not use readelf/nm for .TOC generation, so avoiding polluting
+            # the master ninja with extra unused variables.
+            master_ninja.variable("nm", GetEnvironFallback(["NM_target", "NM"], nm))
+            master_ninja.variable(
+                "readelf", GetEnvironFallback(["READELF_target", "READELF"], readelf)
+            )
+
+    if generator_supports_multiple_toolsets:
+        if not cc_host:
+            cc_host = cc
+        if not cxx_host:
+            cxx_host = cxx
+
+        master_ninja.variable("ar_host", GetEnvironFallback(["AR_host"], ar_host))
+        master_ninja.variable("nm_host", GetEnvironFallback(["NM_host"], nm_host))
+        master_ninja.variable(
+            "readelf_host", GetEnvironFallback(["READELF_host"], readelf_host)
+        )
+        cc_host = GetEnvironFallback(["CC_host"], cc_host)
+        cxx_host = GetEnvironFallback(["CXX_host"], cxx_host)
+
+        # The environment variable could be used in 'make_global_settings', like
+        # ['CC.host', '$(CC)'] or ['CXX.host', '$(CXX)'], transform them here.
+        if "$(CC)" in cc_host and cc_host_global_setting:
+            cc_host = cc_host_global_setting.replace("$(CC)", cc)
+        if "$(CXX)" in cxx_host and cxx_host_global_setting:
+            cxx_host = cxx_host_global_setting.replace("$(CXX)", cxx)
+        master_ninja.variable(
+            "cc_host", CommandWithWrapper("CC.host", wrappers, cc_host)
+        )
+        master_ninja.variable(
+            "cxx_host", CommandWithWrapper("CXX.host", wrappers, cxx_host)
+        )
+        if flavor == "win":
+            master_ninja.variable("ld_host", ld_host)
+        else:
+            master_ninja.variable(
+                "ld_host", CommandWithWrapper("LINK", wrappers, ld_host)
+            )
+            master_ninja.variable(
+                "ldxx_host", CommandWithWrapper("LINK", wrappers, ldxx_host)
+            )
+
+    master_ninja.newline()
+
+    master_ninja.pool("link_pool", depth=GetDefaultConcurrentLinks())
+    master_ninja.newline()
+
+    deps = "msvc" if flavor == "win" else "gcc"
+
+    if flavor != "win":
+        master_ninja.rule(
+            "cc",
+            description="CC $out",
+            command=(
+                "$cc -MMD -MF $out.d $defines $includes $cflags $cflags_c "
+                "$cflags_pch_c -c $in -o $out"
+            ),
+            depfile="$out.d",
+            deps=deps,
+        )
+        master_ninja.rule(
+            "cc_s",
+            description="CC $out",
+            command=(
+                "$cc $defines $includes $cflags $cflags_c "
+                "$cflags_pch_c -c $in -o $out"
+            ),
+        )
+        master_ninja.rule(
+            "cxx",
+            description="CXX $out",
+            command=(
+                "$cxx -MMD -MF $out.d $defines $includes $cflags $cflags_cc "
+                "$cflags_pch_cc -c $in -o $out"
+            ),
+            depfile="$out.d",
+            deps=deps,
+        )
+    else:
+        # TODO(scottmg) Separate pdb names is a test to see if it works around
+        # http://crbug.com/142362. It seems there's a race between the creation of
+        # the .pdb by the precompiled header step for .cc and the compilation of
+        # .c files. This should be handled by mspdbsrv, but rarely errors out with
+        #   c1xx : fatal error C1033: cannot open program database
+        # By making the rules target separate pdb files this might be avoided.
+        cc_command = (
+            "ninja -t msvc -e $arch " + "-- "
+            "$cc /nologo /showIncludes /FC "
+            "@$out.rsp /c $in /Fo$out /Fd$pdbname_c "
+        )
+        cxx_command = (
+            "ninja -t msvc -e $arch " + "-- "
+            "$cxx /nologo /showIncludes /FC "
+            "@$out.rsp /c $in /Fo$out /Fd$pdbname_cc "
+        )
+        master_ninja.rule(
+            "cc",
+            description="CC $out",
+            command=cc_command,
+            rspfile="$out.rsp",
+            rspfile_content="$defines $includes $cflags $cflags_c",
+            deps=deps,
+        )
+        master_ninja.rule(
+            "cxx",
+            description="CXX $out",
+            command=cxx_command,
+            rspfile="$out.rsp",
+            rspfile_content="$defines $includes $cflags $cflags_cc",
+            deps=deps,
+        )
+        master_ninja.rule(
+            "idl",
+            description="IDL $in",
+            command=(
+                "%s gyp-win-tool midl-wrapper $arch $outdir "
+                "$tlb $h $dlldata $iid $proxy $in "
+                "$midl_includes $idlflags" % sys.executable
+            ),
+        )
+        master_ninja.rule(
+            "rc",
+            description="RC $in",
+            # Note: $in must be last otherwise rc.exe complains.
+            command=(
+                "%s gyp-win-tool rc-wrapper "
+                "$arch $rc $defines $resource_includes $rcflags /fo$out $in"
+                % sys.executable
+            ),
+        )
+        master_ninja.rule(
+            "asm",
+            description="ASM $out",
+            command=(
+                "%s gyp-win-tool asm-wrapper "
+                "$arch $asm $defines $includes $asmflags /c /Fo $out $in"
+                % sys.executable
+            ),
+        )
+
+    if flavor != "mac" and flavor != "win":
+        master_ninja.rule(
+            "alink",
+            description="AR $out",
+            command="rm -f $out && $ar rcs $arflags $out $in",
+        )
+        master_ninja.rule(
+            "alink_thin",
+            description="AR $out",
+            command="rm -f $out && $ar rcsT $arflags $out $in",
+        )
+
+        # This allows targets that only need to depend on $lib's API to declare an
+        # order-only dependency on $lib.TOC and avoid relinking such downstream
+        # dependencies when $lib changes only in non-public ways.
+        # The resulting string leaves an uninterpolated %{suffix} which
+        # is used in the final substitution below.
+        mtime_preserving_solink_base = (
+            "if [ ! -e $lib -o ! -e $lib.TOC ]; then "
+            "%(solink)s && %(extract_toc)s > $lib.TOC; else "
+            "%(solink)s && %(extract_toc)s > $lib.tmp && "
+            "if ! cmp -s $lib.tmp $lib.TOC; then mv $lib.tmp $lib.TOC ; "
+            "fi; fi"
+            % {
+                "solink": "$ld -shared $ldflags -o $lib -Wl,-soname=$soname %(suffix)s",
+                "extract_toc": (
+                    "{ $readelf -d $lib | grep SONAME ; "
+                    "$nm -gD -f p $lib | cut -f1-2 -d' '; }"
+                ),
+            }
+        )
+
+        master_ninja.rule(
+            "solink",
+            description="SOLINK $lib",
+            restat=True,
+            command=mtime_preserving_solink_base
+            % {"suffix": "@$link_file_list"},  # noqa: E501
+            rspfile="$link_file_list",
+            rspfile_content=(
+                "-Wl,--whole-archive $in $solibs -Wl," "--no-whole-archive $libs"
+            ),
+            pool="link_pool",
+        )
+        master_ninja.rule(
+            "solink_module",
+            description="SOLINK(module) $lib",
+            restat=True,
+            command=mtime_preserving_solink_base % {"suffix": "@$link_file_list"},
+            rspfile="$link_file_list",
+            rspfile_content="-Wl,--start-group $in $solibs $libs -Wl,--end-group",
+            pool="link_pool",
+        )
+        master_ninja.rule(
+            "link",
+            description="LINK $out",
+            command=(
+                "$ld $ldflags -o $out "
+                "-Wl,--start-group $in $solibs $libs -Wl,--end-group"
+            ),
+            pool="link_pool",
+        )
+    elif flavor == "win":
+        master_ninja.rule(
+            "alink",
+            description="LIB $out",
+            command=(
+                "%s gyp-win-tool link-wrapper $arch False "
+                "$ar /nologo /ignore:4221 /OUT:$out @$out.rsp" % sys.executable
+            ),
+            rspfile="$out.rsp",
+            rspfile_content="$in_newline $libflags",
+        )
+        _AddWinLinkRules(master_ninja, embed_manifest=True)
+        _AddWinLinkRules(master_ninja, embed_manifest=False)
+    else:
+        master_ninja.rule(
+            "objc",
+            description="OBJC $out",
+            command=(
+                "$cc -MMD -MF $out.d $defines $includes $cflags $cflags_objc "
+                "$cflags_pch_objc -c $in -o $out"
+            ),
+            depfile="$out.d",
+            deps=deps,
+        )
+        master_ninja.rule(
+            "objcxx",
+            description="OBJCXX $out",
+            command=(
+                "$cxx -MMD -MF $out.d $defines $includes $cflags $cflags_objcc "
+                "$cflags_pch_objcc -c $in -o $out"
+            ),
+            depfile="$out.d",
+            deps=deps,
+        )
+        master_ninja.rule(
+            "alink",
+            description="LIBTOOL-STATIC $out, POSTBUILDS",
+            command="rm -f $out && "
+            "./gyp-mac-tool filter-libtool libtool $libtool_flags "
+            "-static -o $out $in"
+            "$postbuilds",
+        )
+        master_ninja.rule(
+            "lipo",
+            description="LIPO $out, POSTBUILDS",
+            command="rm -f $out && lipo -create $in -output $out$postbuilds",
+        )
+        master_ninja.rule(
+            "solipo",
+            description="SOLIPO $out, POSTBUILDS",
+            command=(
+                "rm -f $lib $lib.TOC && lipo -create $in -output $lib$postbuilds &&"
+                "%(extract_toc)s > $lib.TOC"
+                % {
+                    "extract_toc": "{ otool -l $lib | grep LC_ID_DYLIB -A 5; "
+                    "nm -gP $lib | cut -f1-2 -d' ' | grep -v U$$; true; }"
+                }
+            ),
+        )
+
+        # Record the public interface of $lib in $lib.TOC. See the corresponding
+        # comment in the posix section above for details.
+        solink_base = "$ld %(type)s $ldflags -o $lib %(suffix)s"
+        mtime_preserving_solink_base = (
+            "if [ ! -e $lib -o ! -e $lib.TOC ] || "
+            # Always force dependent targets to relink if this library
+            # reexports something. Handling this correctly would require
+            # recursive TOC dumping but this is rare in practice, so punt.
+            "otool -l $lib | grep -q LC_REEXPORT_DYLIB ; then "
+            "%(solink)s && %(extract_toc)s > $lib.TOC; "
+            "else "
+            "%(solink)s && %(extract_toc)s > $lib.tmp && "
+            "if ! cmp -s $lib.tmp $lib.TOC; then "
+            "mv $lib.tmp $lib.TOC ; "
+            "fi; "
+            "fi"
+            % {
+                "solink": solink_base,
+                "extract_toc": "{ otool -l $lib | grep LC_ID_DYLIB -A 5; "
+                "nm -gP $lib | cut -f1-2 -d' ' | grep -v U$$; true; }",
+            }
+        )
+
+        solink_suffix = "@$link_file_list$postbuilds"
+        master_ninja.rule(
+            "solink",
+            description="SOLINK $lib, POSTBUILDS",
+            restat=True,
+            command=mtime_preserving_solink_base
+            % {"suffix": solink_suffix, "type": "-shared"},
+            rspfile="$link_file_list",
+            rspfile_content="$in $solibs $libs",
+            pool="link_pool",
+        )
+        master_ninja.rule(
+            "solink_notoc",
+            description="SOLINK $lib, POSTBUILDS",
+            restat=True,
+            command=solink_base % {"suffix": solink_suffix, "type": "-shared"},
+            rspfile="$link_file_list",
+            rspfile_content="$in $solibs $libs",
+            pool="link_pool",
+        )
+
+        master_ninja.rule(
+            "solink_module",
+            description="SOLINK(module) $lib, POSTBUILDS",
+            restat=True,
+            command=mtime_preserving_solink_base
+            % {"suffix": solink_suffix, "type": "-bundle"},
+            rspfile="$link_file_list",
+            rspfile_content="$in $solibs $libs",
+            pool="link_pool",
+        )
+        master_ninja.rule(
+            "solink_module_notoc",
+            description="SOLINK(module) $lib, POSTBUILDS",
+            restat=True,
+            command=solink_base % {"suffix": solink_suffix, "type": "-bundle"},
+            rspfile="$link_file_list",
+            rspfile_content="$in $solibs $libs",
+            pool="link_pool",
+        )
+
+        master_ninja.rule(
+            "link",
+            description="LINK $out, POSTBUILDS",
+            command=("$ld $ldflags -o $out " "$in $solibs $libs$postbuilds"),
+            pool="link_pool",
+        )
+        master_ninja.rule(
+            "preprocess_infoplist",
+            description="PREPROCESS INFOPLIST $out",
+            command=(
+                "$cc -E -P -Wno-trigraphs -x c $defines $in -o $out && "
+                "plutil -convert xml1 $out $out"
+            ),
+        )
+        master_ninja.rule(
+            "copy_infoplist",
+            description="COPY INFOPLIST $in",
+            command="$env ./gyp-mac-tool copy-info-plist $in $out $binary $keys",
+        )
+        master_ninja.rule(
+            "merge_infoplist",
+            description="MERGE INFOPLISTS $in",
+            command="$env ./gyp-mac-tool merge-info-plist $out $in",
+        )
+        master_ninja.rule(
+            "compile_xcassets",
+            description="COMPILE XCASSETS $in",
+            command="$env ./gyp-mac-tool compile-xcassets $keys $in",
+        )
+        master_ninja.rule(
+            "compile_ios_framework_headers",
+            description="COMPILE HEADER MAPS AND COPY FRAMEWORK HEADERS $in",
+            command="$env ./gyp-mac-tool compile-ios-framework-header-map $out "
+            "$framework $in && $env ./gyp-mac-tool "
+            "copy-ios-framework-headers $framework $copy_headers",
+        )
+        master_ninja.rule(
+            "mac_tool",
+            description="MACTOOL $mactool_cmd $in",
+            command="$env ./gyp-mac-tool $mactool_cmd $in $out $binary",
+        )
+        master_ninja.rule(
+            "package_framework",
+            description="PACKAGE FRAMEWORK $out, POSTBUILDS",
+            command="./gyp-mac-tool package-framework $out $version$postbuilds "
+            "&& touch $out",
+        )
+        master_ninja.rule(
+            "package_ios_framework",
+            description="PACKAGE IOS FRAMEWORK $out, POSTBUILDS",
+            command="./gyp-mac-tool package-ios-framework $out $postbuilds "
+            "&& touch $out",
+        )
+    if flavor == "win":
+        master_ninja.rule(
+            "stamp",
+            description="STAMP $out",
+            command="%s gyp-win-tool stamp $out" % sys.executable,
+        )
+    else:
+        master_ninja.rule(
+            "stamp", description="STAMP $out", command="${postbuilds}touch $out"
+        )
+    if flavor == "win":
+        master_ninja.rule(
+            "copy",
+            description="COPY $in $out",
+            command="%s gyp-win-tool recursive-mirror $in $out" % sys.executable,
+        )
+    elif flavor == "zos":
+        master_ninja.rule(
+            "copy",
+            description="COPY $in $out",
+            command="rm -rf $out && cp -fRP $in $out",
+        )
+    else:
+        master_ninja.rule(
+            "copy",
+            description="COPY $in $out",
+            command="ln -f $in $out 2>/dev/null || (rm -rf $out && cp -af $in $out)",
+        )
+    master_ninja.newline()
+
+    all_targets = set()
+    for build_file in params["build_files"]:
+        for target in gyp.common.AllTargets(
+            target_list, target_dicts, os.path.normpath(build_file)
+        ):
+            all_targets.add(target)
+    all_outputs = set()
+
+    # target_outputs is a map from qualified target name to a Target object.
+    target_outputs = {}
+    # target_short_names is a map from target short name to a list of Target
+    # objects.
+    target_short_names = {}
+
+    # short name of targets that were skipped because they didn't contain anything
+    # interesting.
+    # NOTE: there may be overlap between this an non_empty_target_names.
+    empty_target_names = set()
+
+    # Set of non-empty short target names.
+    # NOTE: there may be overlap between this an empty_target_names.
+    non_empty_target_names = set()
+
+    for qualified_target in target_list:
+        # qualified_target is like: third_party/icu/icu.gyp:icui18n#target
+        build_file, name, toolset = gyp.common.ParseQualifiedTarget(qualified_target)
+
+        this_make_global_settings = data[build_file].get("make_global_settings", [])
+        assert make_global_settings == this_make_global_settings, (
+            "make_global_settings needs to be the same for all targets. "
+            f"{this_make_global_settings} vs. {make_global_settings}"
+        )
+
+        spec = target_dicts[qualified_target]
+        if flavor == "mac":
+            gyp.xcode_emulation.MergeGlobalXcodeSettingsToSpec(data[build_file], spec)
+
+        # If build_file is a symlink, we must not follow it because there's a chance
+        # it could point to a path above toplevel_dir, and we cannot correctly deal
+        # with that case at the moment.
+        build_file = gyp.common.RelativePath(build_file, options.toplevel_dir, False)
+
+        qualified_target_for_hash = gyp.common.QualifiedTarget(
+            build_file, name, toolset
+        )
+        qualified_target_for_hash = qualified_target_for_hash.encode("utf-8")
+        hash_for_rules = hashlib.md5(qualified_target_for_hash).hexdigest()
+
+        base_path = os.path.dirname(build_file)
+        obj = "obj"
+        if toolset != "target":
+            obj += "." + toolset
+        output_file = os.path.join(obj, base_path, name + ".ninja")
+
+        ninja_output = StringIO()
+        writer = NinjaWriter(
+            hash_for_rules,
+            target_outputs,
+            base_path,
+            build_dir,
+            ninja_output,
+            toplevel_build,
+            output_file,
+            flavor,
+            toplevel_dir=options.toplevel_dir,
+        )
+
+        target = writer.WriteSpec(spec, config_name, generator_flags)
+
+        if ninja_output.tell() > 0:
+            # Only create files for ninja files that actually have contents.
+            with OpenOutput(os.path.join(toplevel_build, output_file)) as ninja_file:
+                ninja_file.write(ninja_output.getvalue())
+            ninja_output.close()
+            master_ninja.subninja(output_file)
+
+        if target:
+            if name != target.FinalOutput() and spec["toolset"] == "target":
+                target_short_names.setdefault(name, []).append(target)
+            target_outputs[qualified_target] = target
+            if qualified_target in all_targets:
+                all_outputs.add(target.FinalOutput())
+            non_empty_target_names.add(name)
+        else:
+            empty_target_names.add(name)
+
+    if target_short_names:
+        # Write a short name to build this target.  This benefits both the
+        # "build chrome" case as well as the gyp tests, which expect to be
+        # able to run actions and build libraries by their short name.
+        master_ninja.newline()
+        master_ninja.comment("Short names for targets.")
+        for short_name in sorted(target_short_names):
+            master_ninja.build(
+                short_name,
+                "phony",
+                [x.FinalOutput() for x in target_short_names[short_name]],
+            )
+
+    # Write phony targets for any empty targets that weren't written yet. As
+    # short names are  not necessarily unique only do this for short names that
+    # haven't already been output for another target.
+    empty_target_names = empty_target_names - non_empty_target_names
+    if empty_target_names:
+        master_ninja.newline()
+        master_ninja.comment("Empty targets (output for completeness).")
+        for name in sorted(empty_target_names):
+            master_ninja.build(name, "phony")
+
+    if all_outputs:
+        master_ninja.newline()
+        master_ninja.build("all", "phony", sorted(all_outputs))
+        master_ninja.default(generator_flags.get("default_target", "all"))
+
+    master_ninja_file.close()
+
+
+def PerformBuild(data, configurations, params):
+    options = params["options"]
+    for config in configurations:
+        builddir = os.path.join(options.toplevel_dir, "out", config)
+        arguments = ["ninja", "-C", builddir]
+        print(f"Building [{config}]: {arguments}")
+        subprocess.check_call(arguments)
+
+
+def CallGenerateOutputForConfig(arglist):
+    # Ignore the interrupt signal so that the parent process catches it and
+    # kills all multiprocessing children.
+    signal.signal(signal.SIGINT, signal.SIG_IGN)
+
+    (target_list, target_dicts, data, params, config_name) = arglist
+    GenerateOutputForConfig(target_list, target_dicts, data, params, config_name)
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    # Update target_dicts for iOS device builds.
+    target_dicts = gyp.xcode_emulation.CloneConfigurationForDeviceAndEmulator(
+        target_dicts
+    )
+
+    user_config = params.get("generator_flags", {}).get("config", None)
+    if gyp.common.GetFlavor(params) == "win":
+        target_list, target_dicts = MSVSUtil.ShardTargets(target_list, target_dicts)
+        target_list, target_dicts = MSVSUtil.InsertLargePdbShims(
+            target_list, target_dicts, generator_default_variables
+        )
+
+    if user_config:
+        GenerateOutputForConfig(target_list, target_dicts, data, params, user_config)
+    else:
+        config_names = target_dicts[target_list[0]]["configurations"]
+        if params["parallel"]:
+            try:
+                pool = multiprocessing.Pool(len(config_names))
+                arglists = []
+                for config_name in config_names:
+                    arglists.append(
+                        (target_list, target_dicts, data, params, config_name)
+                    )
+                pool.map(CallGenerateOutputForConfig, arglists)
+            except KeyboardInterrupt as e:
+                pool.terminate()
+                raise e
+        else:
+            for config_name in config_names:
+                GenerateOutputForConfig(
+                    target_list, target_dicts, data, params, config_name
+                )
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/ninja_test.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/ninja_test.py
new file mode 100644
index 0000000..7d18068
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/ninja_test.py
@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+""" Unit tests for the ninja.py file. """
+
+import sys
+import unittest
+
+import gyp.generator.ninja as ninja
+
+
+class TestPrefixesAndSuffixes(unittest.TestCase):
+    def test_BinaryNamesWindows(self):
+        # These cannot run on non-Windows as they require a VS installation to
+        # correctly handle variable expansion.
+        if sys.platform.startswith("win"):
+            writer = ninja.NinjaWriter(
+                "foo", "wee", ".", ".", "build.ninja", ".", "build.ninja", "win"
+            )
+            spec = {"target_name": "wee"}
+            self.assertTrue(
+                writer.ComputeOutputFileName(spec, "executable").endswith(".exe")
+            )
+            self.assertTrue(
+                writer.ComputeOutputFileName(spec, "shared_library").endswith(".dll")
+            )
+            self.assertTrue(
+                writer.ComputeOutputFileName(spec, "static_library").endswith(".lib")
+            )
+
+    def test_BinaryNamesLinux(self):
+        writer = ninja.NinjaWriter(
+            "foo", "wee", ".", ".", "build.ninja", ".", "build.ninja", "linux"
+        )
+        spec = {"target_name": "wee"}
+        self.assertTrue("." not in writer.ComputeOutputFileName(spec, "executable"))
+        self.assertTrue(
+            writer.ComputeOutputFileName(spec, "shared_library").startswith("lib")
+        )
+        self.assertTrue(
+            writer.ComputeOutputFileName(spec, "static_library").startswith("lib")
+        )
+        self.assertTrue(
+            writer.ComputeOutputFileName(spec, "shared_library").endswith(".so")
+        )
+        self.assertTrue(
+            writer.ComputeOutputFileName(spec, "static_library").endswith(".a")
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/xcode.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/xcode.py
new file mode 100644
index 0000000..2f4d17e
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/xcode.py
@@ -0,0 +1,1394 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+import filecmp
+import gyp.common
+import gyp.xcodeproj_file
+import gyp.xcode_ninja
+import errno
+import os
+import sys
+import posixpath
+import re
+import shutil
+import subprocess
+import tempfile
+
+
+# Project files generated by this module will use _intermediate_var as a
+# custom Xcode setting whose value is a DerivedSources-like directory that's
+# project-specific and configuration-specific.  The normal choice,
+# DERIVED_FILE_DIR, is target-specific, which is thought to be too restrictive
+# as it is likely that multiple targets within a single project file will want
+# to access the same set of generated files.  The other option,
+# PROJECT_DERIVED_FILE_DIR, is unsuitable because while it is project-specific,
+# it is not configuration-specific.  INTERMEDIATE_DIR is defined as
+# $(PROJECT_DERIVED_FILE_DIR)/$(CONFIGURATION).
+_intermediate_var = "INTERMEDIATE_DIR"
+
+# SHARED_INTERMEDIATE_DIR is the same, except that it is shared among all
+# targets that share the same BUILT_PRODUCTS_DIR.
+_shared_intermediate_var = "SHARED_INTERMEDIATE_DIR"
+
+_library_search_paths_var = "LIBRARY_SEARCH_PATHS"
+
+generator_default_variables = {
+    "EXECUTABLE_PREFIX": "",
+    "EXECUTABLE_SUFFIX": "",
+    "STATIC_LIB_PREFIX": "lib",
+    "SHARED_LIB_PREFIX": "lib",
+    "STATIC_LIB_SUFFIX": ".a",
+    "SHARED_LIB_SUFFIX": ".dylib",
+    # INTERMEDIATE_DIR is a place for targets to build up intermediate products.
+    # It is specific to each build environment.  It is only guaranteed to exist
+    # and be constant within the context of a project, corresponding to a single
+    # input file.  Some build environments may allow their intermediate directory
+    # to be shared on a wider scale, but this is not guaranteed.
+    "INTERMEDIATE_DIR": "$(%s)" % _intermediate_var,
+    "OS": "mac",
+    "PRODUCT_DIR": "$(BUILT_PRODUCTS_DIR)",
+    "LIB_DIR": "$(BUILT_PRODUCTS_DIR)",
+    "RULE_INPUT_ROOT": "$(INPUT_FILE_BASE)",
+    "RULE_INPUT_EXT": "$(INPUT_FILE_SUFFIX)",
+    "RULE_INPUT_NAME": "$(INPUT_FILE_NAME)",
+    "RULE_INPUT_PATH": "$(INPUT_FILE_PATH)",
+    "RULE_INPUT_DIRNAME": "$(INPUT_FILE_DIRNAME)",
+    "SHARED_INTERMEDIATE_DIR": "$(%s)" % _shared_intermediate_var,
+    "CONFIGURATION_NAME": "$(CONFIGURATION)",
+}
+
+# The Xcode-specific sections that hold paths.
+generator_additional_path_sections = [
+    "mac_bundle_resources",
+    "mac_framework_headers",
+    "mac_framework_private_headers",
+    # 'mac_framework_dirs', input already handles _dirs endings.
+]
+
+# The Xcode-specific keys that exist on targets and aren't moved down to
+# configurations.
+generator_additional_non_configuration_keys = [
+    "ios_app_extension",
+    "ios_watch_app",
+    "ios_watchkit_extension",
+    "mac_bundle",
+    "mac_bundle_resources",
+    "mac_framework_headers",
+    "mac_framework_private_headers",
+    "mac_xctest_bundle",
+    "mac_xcuitest_bundle",
+    "xcode_create_dependents_test_runner",
+]
+
+# We want to let any rules apply to files that are resources also.
+generator_extra_sources_for_rules = [
+    "mac_bundle_resources",
+    "mac_framework_headers",
+    "mac_framework_private_headers",
+]
+
+generator_filelist_paths = None
+
+# Xcode's standard set of library directories, which don't need to be duplicated
+# in LIBRARY_SEARCH_PATHS. This list is not exhaustive, but that's okay.
+xcode_standard_library_dirs = frozenset(
+    ["$(SDKROOT)/usr/lib", "$(SDKROOT)/usr/local/lib"]
+)
+
+
+def CreateXCConfigurationList(configuration_names):
+    xccl = gyp.xcodeproj_file.XCConfigurationList({"buildConfigurations": []})
+    if len(configuration_names) == 0:
+        configuration_names = ["Default"]
+    for configuration_name in configuration_names:
+        xcbc = gyp.xcodeproj_file.XCBuildConfiguration({"name": configuration_name})
+        xccl.AppendProperty("buildConfigurations", xcbc)
+    xccl.SetProperty("defaultConfigurationName", configuration_names[0])
+    return xccl
+
+
+class XcodeProject:
+    def __init__(self, gyp_path, path, build_file_dict):
+        self.gyp_path = gyp_path
+        self.path = path
+        self.project = gyp.xcodeproj_file.PBXProject(path=path)
+        projectDirPath = gyp.common.RelativePath(
+            os.path.dirname(os.path.abspath(self.gyp_path)),
+            os.path.dirname(path) or ".",
+        )
+        self.project.SetProperty("projectDirPath", projectDirPath)
+        self.project_file = gyp.xcodeproj_file.XCProjectFile(
+            {"rootObject": self.project}
+        )
+        self.build_file_dict = build_file_dict
+
+        # TODO(mark): add destructor that cleans up self.path if created_dir is
+        # True and things didn't complete successfully.  Or do something even
+        # better with "try"?
+        self.created_dir = False
+        try:
+            os.makedirs(self.path)
+            self.created_dir = True
+        except OSError as e:
+            if e.errno != errno.EEXIST:
+                raise
+
+    def Finalize1(self, xcode_targets, serialize_all_tests):
+        # Collect a list of all of the build configuration names used by the
+        # various targets in the file.  It is very heavily advised to keep each
+        # target in an entire project (even across multiple project files) using
+        # the same set of configuration names.
+        configurations = []
+        for xct in self.project.GetProperty("targets"):
+            xccl = xct.GetProperty("buildConfigurationList")
+            xcbcs = xccl.GetProperty("buildConfigurations")
+            for xcbc in xcbcs:
+                name = xcbc.GetProperty("name")
+                if name not in configurations:
+                    configurations.append(name)
+
+        # Replace the XCConfigurationList attached to the PBXProject object with
+        # a new one specifying all of the configuration names used by the various
+        # targets.
+        try:
+            xccl = CreateXCConfigurationList(configurations)
+            self.project.SetProperty("buildConfigurationList", xccl)
+        except Exception:
+            sys.stderr.write("Problem with gyp file %s\n" % self.gyp_path)
+            raise
+
+        # The need for this setting is explained above where _intermediate_var is
+        # defined.  The comments below about wanting to avoid project-wide build
+        # settings apply here too, but this needs to be set on a project-wide basis
+        # so that files relative to the _intermediate_var setting can be displayed
+        # properly in the Xcode UI.
+        #
+        # Note that for configuration-relative files such as anything relative to
+        # _intermediate_var, for the purposes of UI tree view display, Xcode will
+        # only resolve the configuration name once, when the project file is
+        # opened.  If the active build configuration is changed, the project file
+        # must be closed and reopened if it is desired for the tree view to update.
+        # This is filed as Apple radar 6588391.
+        xccl.SetBuildSetting(
+            _intermediate_var, "$(PROJECT_DERIVED_FILE_DIR)/$(CONFIGURATION)"
+        )
+        xccl.SetBuildSetting(
+            _shared_intermediate_var, "$(SYMROOT)/DerivedSources/$(CONFIGURATION)"
+        )
+
+        # Set user-specified project-wide build settings and config files.  This
+        # is intended to be used very sparingly.  Really, almost everything should
+        # go into target-specific build settings sections.  The project-wide
+        # settings are only intended to be used in cases where Xcode attempts to
+        # resolve variable references in a project context as opposed to a target
+        # context, such as when resolving sourceTree references while building up
+        # the tree tree view for UI display.
+        # Any values set globally are applied to all configurations, then any
+        # per-configuration values are applied.
+        for xck, xcv in self.build_file_dict.get("xcode_settings", {}).items():
+            xccl.SetBuildSetting(xck, xcv)
+        if "xcode_config_file" in self.build_file_dict:
+            config_ref = self.project.AddOrGetFileInRootGroup(
+                self.build_file_dict["xcode_config_file"]
+            )
+            xccl.SetBaseConfiguration(config_ref)
+        build_file_configurations = self.build_file_dict.get("configurations", {})
+        if build_file_configurations:
+            for config_name in configurations:
+                build_file_configuration_named = build_file_configurations.get(
+                    config_name, {}
+                )
+                if build_file_configuration_named:
+                    xcc = xccl.ConfigurationNamed(config_name)
+                    for xck, xcv in build_file_configuration_named.get(
+                        "xcode_settings", {}
+                    ).items():
+                        xcc.SetBuildSetting(xck, xcv)
+                    if "xcode_config_file" in build_file_configuration_named:
+                        config_ref = self.project.AddOrGetFileInRootGroup(
+                            build_file_configurations[config_name]["xcode_config_file"]
+                        )
+                        xcc.SetBaseConfiguration(config_ref)
+
+        # Sort the targets based on how they appeared in the input.
+        # TODO(mark): Like a lot of other things here, this assumes internal
+        # knowledge of PBXProject - in this case, of its "targets" property.
+
+        # ordinary_targets are ordinary targets that are already in the project
+        # file. run_test_targets are the targets that run unittests and should be
+        # used for the Run All Tests target.  support_targets are the action/rule
+        # targets used by GYP file targets, just kept for the assert check.
+        ordinary_targets = []
+        run_test_targets = []
+        support_targets = []
+
+        # targets is full list of targets in the project.
+        targets = []
+
+        # does the it define it's own "all"?
+        has_custom_all = False
+
+        # targets_for_all is the list of ordinary_targets that should be listed
+        # in this project's "All" target.  It includes each non_runtest_target
+        # that does not have suppress_wildcard set.
+        targets_for_all = []
+
+        for target in self.build_file_dict["targets"]:
+            target_name = target["target_name"]
+            toolset = target["toolset"]
+            qualified_target = gyp.common.QualifiedTarget(
+                self.gyp_path, target_name, toolset
+            )
+            xcode_target = xcode_targets[qualified_target]
+            # Make sure that the target being added to the sorted list is already in
+            # the unsorted list.
+            assert xcode_target in self.project._properties["targets"]
+            targets.append(xcode_target)
+            ordinary_targets.append(xcode_target)
+            if xcode_target.support_target:
+                support_targets.append(xcode_target.support_target)
+                targets.append(xcode_target.support_target)
+
+            if not int(target.get("suppress_wildcard", False)):
+                targets_for_all.append(xcode_target)
+
+            if target_name.lower() == "all":
+                has_custom_all = True
+
+            # If this target has a 'run_as' attribute, add its target to the
+            # targets, and add it to the test targets.
+            if target.get("run_as"):
+                # Make a target to run something.  It should have one
+                # dependency, the parent xcode target.
+                xccl = CreateXCConfigurationList(configurations)
+                run_target = gyp.xcodeproj_file.PBXAggregateTarget(
+                    {
+                        "name": "Run " + target_name,
+                        "productName": xcode_target.GetProperty("productName"),
+                        "buildConfigurationList": xccl,
+                    },
+                    parent=self.project,
+                )
+                run_target.AddDependency(xcode_target)
+
+                command = target["run_as"]
+                script = ""
+                if command.get("working_directory"):
+                    script = (
+                        script
+                        + 'cd "%s"\n'
+                        % gyp.xcodeproj_file.ConvertVariablesToShellSyntax(
+                            command.get("working_directory")
+                        )
+                    )
+
+                if command.get("environment"):
+                    script = (
+                        script
+                        + "\n".join(
+                            [
+                                'export %s="%s"'
+                                % (
+                                    key,
+                                    gyp.xcodeproj_file.ConvertVariablesToShellSyntax(
+                                        val
+                                    ),
+                                )
+                                for (key, val) in command.get("environment").items()
+                            ]
+                        )
+                        + "\n"
+                    )
+
+                # Some test end up using sockets, files on disk, etc. and can get
+                # confused if more then one test runs at a time.  The generator
+                # flag 'xcode_serialize_all_test_runs' controls the forcing of all
+                # tests serially.  It defaults to True.  To get serial runs this
+                # little bit of python does the same as the linux flock utility to
+                # make sure only one runs at a time.
+                command_prefix = ""
+                if serialize_all_tests:
+                    command_prefix = """python -c "import fcntl, subprocess, sys
+file = open('$TMPDIR/GYP_serialize_test_runs', 'a')
+fcntl.flock(file.fileno(), fcntl.LOCK_EX)
+sys.exit(subprocess.call(sys.argv[1:]))" """
+
+                # If we were unable to exec for some reason, we want to exit
+                # with an error, and fixup variable references to be shell
+                # syntax instead of xcode syntax.
+                script = (
+                    script
+                    + "exec "
+                    + command_prefix
+                    + "%s\nexit 1\n"
+                    % gyp.xcodeproj_file.ConvertVariablesToShellSyntax(
+                        gyp.common.EncodePOSIXShellList(command.get("action"))
+                    )
+                )
+
+                ssbp = gyp.xcodeproj_file.PBXShellScriptBuildPhase(
+                    {"shellScript": script, "showEnvVarsInLog": 0}
+                )
+                run_target.AppendProperty("buildPhases", ssbp)
+
+                # Add the run target to the project file.
+                targets.append(run_target)
+                run_test_targets.append(run_target)
+                xcode_target.test_runner = run_target
+
+        # Make sure that the list of targets being replaced is the same length as
+        # the one replacing it, but allow for the added test runner targets.
+        assert len(self.project._properties["targets"]) == len(ordinary_targets) + len(
+            support_targets
+        )
+
+        self.project._properties["targets"] = targets
+
+        # Get rid of unnecessary levels of depth in groups like the Source group.
+        self.project.RootGroupsTakeOverOnlyChildren(True)
+
+        # Sort the groups nicely.  Do this after sorting the targets, because the
+        # Products group is sorted based on the order of the targets.
+        self.project.SortGroups()
+
+        # Create an "All" target if there's more than one target in this project
+        # file and the project didn't define its own "All" target.  Put a generated
+        # "All" target first so that people opening up the project for the first
+        # time will build everything by default.
+        if len(targets_for_all) > 1 and not has_custom_all:
+            xccl = CreateXCConfigurationList(configurations)
+            all_target = gyp.xcodeproj_file.PBXAggregateTarget(
+                {"buildConfigurationList": xccl, "name": "All"}, parent=self.project
+            )
+
+            for target in targets_for_all:
+                all_target.AddDependency(target)
+
+            # TODO(mark): This is evil because it relies on internal knowledge of
+            # PBXProject._properties.  It's important to get the "All" target first,
+            # though.
+            self.project._properties["targets"].insert(0, all_target)
+
+        # The same, but for run_test_targets.
+        if len(run_test_targets) > 1:
+            xccl = CreateXCConfigurationList(configurations)
+            run_all_tests_target = gyp.xcodeproj_file.PBXAggregateTarget(
+                {"buildConfigurationList": xccl, "name": "Run All Tests"},
+                parent=self.project,
+            )
+            for run_test_target in run_test_targets:
+                run_all_tests_target.AddDependency(run_test_target)
+
+            # Insert after the "All" target, which must exist if there is more than
+            # one run_test_target.
+            self.project._properties["targets"].insert(1, run_all_tests_target)
+
+    def Finalize2(self, xcode_targets, xcode_target_to_target_dict):
+        # Finalize2 needs to happen in a separate step because the process of
+        # updating references to other projects depends on the ordering of targets
+        # within remote project files.  Finalize1 is responsible for sorting duty,
+        # and once all project files are sorted, Finalize2 can come in and update
+        # these references.
+
+        # To support making a "test runner" target that will run all the tests
+        # that are direct dependents of any given target, we look for
+        # xcode_create_dependents_test_runner being set on an Aggregate target,
+        # and generate a second target that will run the tests runners found under
+        # the marked target.
+        for bf_tgt in self.build_file_dict["targets"]:
+            if int(bf_tgt.get("xcode_create_dependents_test_runner", 0)):
+                tgt_name = bf_tgt["target_name"]
+                toolset = bf_tgt["toolset"]
+                qualified_target = gyp.common.QualifiedTarget(
+                    self.gyp_path, tgt_name, toolset
+                )
+                xcode_target = xcode_targets[qualified_target]
+                if isinstance(xcode_target, gyp.xcodeproj_file.PBXAggregateTarget):
+                    # Collect all the run test targets.
+                    all_run_tests = []
+                    pbxtds = xcode_target.GetProperty("dependencies")
+                    for pbxtd in pbxtds:
+                        pbxcip = pbxtd.GetProperty("targetProxy")
+                        dependency_xct = pbxcip.GetProperty("remoteGlobalIDString")
+                        if hasattr(dependency_xct, "test_runner"):
+                            all_run_tests.append(dependency_xct.test_runner)
+
+                    # Directly depend on all the runners as they depend on the target
+                    # that builds them.
+                    if len(all_run_tests) > 0:
+                        run_all_target = gyp.xcodeproj_file.PBXAggregateTarget(
+                            {
+                                "name": "Run %s Tests" % tgt_name,
+                                "productName": tgt_name,
+                            },
+                            parent=self.project,
+                        )
+                        for run_test_target in all_run_tests:
+                            run_all_target.AddDependency(run_test_target)
+
+                        # Insert the test runner after the related target.
+                        idx = self.project._properties["targets"].index(xcode_target)
+                        self.project._properties["targets"].insert(
+                            idx + 1, run_all_target
+                        )
+
+        # Update all references to other projects, to make sure that the lists of
+        # remote products are complete.  Otherwise, Xcode will fill them in when
+        # it opens the project file, which will result in unnecessary diffs.
+        # TODO(mark): This is evil because it relies on internal knowledge of
+        # PBXProject._other_pbxprojects.
+        for other_pbxproject in self.project._other_pbxprojects.keys():
+            self.project.AddOrGetProjectReference(other_pbxproject)
+
+        self.project.SortRemoteProductReferences()
+
+        # Give everything an ID.
+        self.project_file.ComputeIDs()
+
+        # Make sure that no two objects in the project file have the same ID.  If
+        # multiple objects wind up with the same ID, upon loading the file, Xcode
+        # will only recognize one object (the last one in the file?) and the
+        # results are unpredictable.
+        self.project_file.EnsureNoIDCollisions()
+
+    def Write(self):
+        # Write the project file to a temporary location first.  Xcode watches for
+        # changes to the project file and presents a UI sheet offering to reload
+        # the project when it does change.  However, in some cases, especially when
+        # multiple projects are open or when Xcode is busy, things don't work so
+        # seamlessly.  Sometimes, Xcode is able to detect that a project file has
+        # changed but can't unload it because something else is referencing it.
+        # To mitigate this problem, and to avoid even having Xcode present the UI
+        # sheet when an open project is rewritten for inconsequential changes, the
+        # project file is written to a temporary file in the xcodeproj directory
+        # first.  The new temporary file is then compared to the existing project
+        # file, if any.  If they differ, the new file replaces the old; otherwise,
+        # the new project file is simply deleted.  Xcode properly detects a file
+        # being renamed over an open project file as a change and so it remains
+        # able to present the "project file changed" sheet under this system.
+        # Writing to a temporary file first also avoids the possible problem of
+        # Xcode rereading an incomplete project file.
+        (output_fd, new_pbxproj_path) = tempfile.mkstemp(
+            suffix=".tmp", prefix="project.pbxproj.gyp.", dir=self.path
+        )
+
+        try:
+            output_file = os.fdopen(output_fd, "w")
+
+            self.project_file.Print(output_file)
+            output_file.close()
+
+            pbxproj_path = os.path.join(self.path, "project.pbxproj")
+
+            same = False
+            try:
+                same = filecmp.cmp(pbxproj_path, new_pbxproj_path, False)
+            except OSError as e:
+                if e.errno != errno.ENOENT:
+                    raise
+
+            if same:
+                # The new file is identical to the old one, just get rid of the new
+                # one.
+                os.unlink(new_pbxproj_path)
+            else:
+                # The new file is different from the old one, or there is no old one.
+                # Rename the new file to the permanent name.
+                #
+                # tempfile.mkstemp uses an overly restrictive mode, resulting in a
+                # file that can only be read by the owner, regardless of the umask.
+                # There's no reason to not respect the umask here, which means that
+                # an extra hoop is required to fetch it and reset the new file's mode.
+                #
+                # No way to get the umask without setting a new one?  Set a safe one
+                # and then set it back to the old value.
+                umask = os.umask(0o77)
+                os.umask(umask)
+
+                os.chmod(new_pbxproj_path, 0o666 & ~umask)
+                os.rename(new_pbxproj_path, pbxproj_path)
+
+        except Exception:
+            # Don't leave turds behind.  In fact, if this code was responsible for
+            # creating the xcodeproj directory, get rid of that too.
+            os.unlink(new_pbxproj_path)
+            if self.created_dir:
+                shutil.rmtree(self.path, True)
+            raise
+
+
+def AddSourceToTarget(source, type, pbxp, xct):
+    # TODO(mark): Perhaps source_extensions and library_extensions can be made a
+    # little bit fancier.
+    source_extensions = ["c", "cc", "cpp", "cxx", "m", "mm", "s", "swift"]
+
+    # .o is conceptually more of a "source" than a "library," but Xcode thinks
+    # of "sources" as things to compile and "libraries" (or "frameworks") as
+    # things to link with. Adding an object file to an Xcode target's frameworks
+    # phase works properly.
+    library_extensions = ["a", "dylib", "framework", "o"]
+
+    basename = posixpath.basename(source)
+    (root, ext) = posixpath.splitext(basename)
+    if ext:
+        ext = ext[1:].lower()
+
+    if ext in source_extensions and type != "none":
+        xct.SourcesPhase().AddFile(source)
+    elif ext in library_extensions and type != "none":
+        xct.FrameworksPhase().AddFile(source)
+    else:
+        # Files that aren't added to a sources or frameworks build phase can still
+        # go into the project file, just not as part of a build phase.
+        pbxp.AddOrGetFileInRootGroup(source)
+
+
+def AddResourceToTarget(resource, pbxp, xct):
+    # TODO(mark): Combine with AddSourceToTarget above?  Or just inline this call
+    # where it's used.
+    xct.ResourcesPhase().AddFile(resource)
+
+
+def AddHeaderToTarget(header, pbxp, xct, is_public):
+    # TODO(mark): Combine with AddSourceToTarget above?  Or just inline this call
+    # where it's used.
+    settings = "{ATTRIBUTES = (%s, ); }" % ("Private", "Public")[is_public]
+    xct.HeadersPhase().AddFile(header, settings)
+
+
+_xcode_variable_re = re.compile(r"(\$$(.*?)$)")
+
+
+def ExpandXcodeVariables(string, expansions):
+    """Expands Xcode-style $(VARIABLES) in string per the expansions dict.
+
+  In some rare cases, it is appropriate to expand Xcode variables when a
+  project file is generated.  For any substring $(VAR) in string, if VAR is a
+  key in the expansions dict, $(VAR) will be replaced with expansions[VAR].
+  Any $(VAR) substring in string for which VAR is not a key in the expansions
+  dict will remain in the returned string.
+  """
+
+    matches = _xcode_variable_re.findall(string)
+    if matches is None:
+        return string
+
+    matches.reverse()
+    for match in matches:
+        (to_replace, variable) = match
+        if variable not in expansions:
+            continue
+
+        replacement = expansions[variable]
+        string = re.sub(re.escape(to_replace), replacement, string)
+
+    return string
+
+
+_xcode_define_re = re.compile(r"([\\\"\' ])")
+
+
+def EscapeXcodeDefine(s):
+    """We must escape the defines that we give to XCode so that it knows not to
+     split on spaces and to respect backslash and quote literals. However, we
+     must not quote the define, or Xcode will incorrectly interpret variables
+     especially $(inherited)."""
+    return re.sub(_xcode_define_re, r"\\\1", s)
+
+
+def PerformBuild(data, configurations, params):
+    options = params["options"]
+
+    for build_file, build_file_dict in data.items():
+        (build_file_root, build_file_ext) = os.path.splitext(build_file)
+        if build_file_ext != ".gyp":
+            continue
+        xcodeproj_path = build_file_root + options.suffix + ".xcodeproj"
+        if options.generator_output:
+            xcodeproj_path = os.path.join(options.generator_output, xcodeproj_path)
+
+    for config in configurations:
+        arguments = ["xcodebuild", "-project", xcodeproj_path]
+        arguments += ["-configuration", config]
+        print(f"Building [{config}]: {arguments}")
+        subprocess.check_call(arguments)
+
+
+def CalculateGeneratorInputInfo(params):
+    toplevel = params["options"].toplevel_dir
+    if params.get("flavor") == "ninja":
+        generator_dir = os.path.relpath(params["options"].generator_output or ".")
+        output_dir = params.get("generator_flags", {}).get("output_dir", "out")
+        output_dir = os.path.normpath(os.path.join(generator_dir, output_dir))
+        qualified_out_dir = os.path.normpath(
+            os.path.join(toplevel, output_dir, "gypfiles-xcode-ninja")
+        )
+    else:
+        output_dir = os.path.normpath(os.path.join(toplevel, "xcodebuild"))
+        qualified_out_dir = os.path.normpath(
+            os.path.join(toplevel, output_dir, "gypfiles")
+        )
+
+    global generator_filelist_paths
+    generator_filelist_paths = {
+        "toplevel": toplevel,
+        "qualified_out_dir": qualified_out_dir,
+    }
+
+
+def GenerateOutput(target_list, target_dicts, data, params):
+    # Optionally configure each spec to use ninja as the external builder.
+    ninja_wrapper = params.get("flavor") == "ninja"
+    if ninja_wrapper:
+        (target_list, target_dicts, data) = gyp.xcode_ninja.CreateWrapper(
+            target_list, target_dicts, data, params
+        )
+
+    options = params["options"]
+    generator_flags = params.get("generator_flags", {})
+    parallel_builds = generator_flags.get("xcode_parallel_builds", True)
+    serialize_all_tests = generator_flags.get("xcode_serialize_all_test_runs", True)
+    upgrade_check_project_version = generator_flags.get(
+        "xcode_upgrade_check_project_version", None
+    )
+
+    # Format upgrade_check_project_version with leading zeros as needed.
+    if upgrade_check_project_version:
+        upgrade_check_project_version = str(upgrade_check_project_version)
+        while len(upgrade_check_project_version) < 4:
+            upgrade_check_project_version = "0" + upgrade_check_project_version
+
+    skip_excluded_files = not generator_flags.get("xcode_list_excluded_files", True)
+    xcode_projects = {}
+    for build_file, build_file_dict in data.items():
+        (build_file_root, build_file_ext) = os.path.splitext(build_file)
+        if build_file_ext != ".gyp":
+            continue
+        xcodeproj_path = build_file_root + options.suffix + ".xcodeproj"
+        if options.generator_output:
+            xcodeproj_path = os.path.join(options.generator_output, xcodeproj_path)
+        xcp = XcodeProject(build_file, xcodeproj_path, build_file_dict)
+        xcode_projects[build_file] = xcp
+        pbxp = xcp.project
+
+        # Set project-level attributes from multiple options
+        project_attributes = {}
+        if parallel_builds:
+            project_attributes["BuildIndependentTargetsInParallel"] = "YES"
+        if upgrade_check_project_version:
+            project_attributes["LastUpgradeCheck"] = upgrade_check_project_version
+            project_attributes[
+                "LastTestingUpgradeCheck"
+            ] = upgrade_check_project_version
+            project_attributes["LastSwiftUpdateCheck"] = upgrade_check_project_version
+        pbxp.SetProperty("attributes", project_attributes)
+
+        # Add gyp/gypi files to project
+        if not generator_flags.get("standalone"):
+            main_group = pbxp.GetProperty("mainGroup")
+            build_group = gyp.xcodeproj_file.PBXGroup({"name": "Build"})
+            main_group.AppendChild(build_group)
+            for included_file in build_file_dict["included_files"]:
+                build_group.AddOrGetFileByPath(included_file, False)
+
+    xcode_targets = {}
+    xcode_target_to_target_dict = {}
+    for qualified_target in target_list:
+        [build_file, target_name, toolset] = gyp.common.ParseQualifiedTarget(
+            qualified_target
+        )
+
+        spec = target_dicts[qualified_target]
+        if spec["toolset"] != "target":
+            raise Exception(
+                "Multiple toolsets not supported in xcode build (target %s)"
+                % qualified_target
+            )
+        configuration_names = [spec["default_configuration"]]
+        for configuration_name in sorted(spec["configurations"].keys()):
+            if configuration_name not in configuration_names:
+                configuration_names.append(configuration_name)
+        xcp = xcode_projects[build_file]
+        pbxp = xcp.project
+
+        # Set up the configurations for the target according to the list of names
+        # supplied.
+        xccl = CreateXCConfigurationList(configuration_names)
+
+        # Create an XCTarget subclass object for the target. The type with
+        # "+bundle" appended will be used if the target has "mac_bundle" set.
+        # loadable_modules not in a mac_bundle are mapped to
+        # com.googlecode.gyp.xcode.bundle, a pseudo-type that xcode.py interprets
+        # to create a single-file mh_bundle.
+        _types = {
+            "executable": "com.apple.product-type.tool",
+            "loadable_module": "com.googlecode.gyp.xcode.bundle",
+            "shared_library": "com.apple.product-type.library.dynamic",
+            "static_library": "com.apple.product-type.library.static",
+            "mac_kernel_extension": "com.apple.product-type.kernel-extension",
+            "executable+bundle": "com.apple.product-type.application",
+            "loadable_module+bundle": "com.apple.product-type.bundle",
+            "loadable_module+xctest": "com.apple.product-type.bundle.unit-test",
+            "loadable_module+xcuitest": "com.apple.product-type.bundle.ui-testing",
+            "shared_library+bundle": "com.apple.product-type.framework",
+            "executable+extension+bundle": "com.apple.product-type.app-extension",
+            "executable+watch+extension+bundle":
+                "com.apple.product-type.watchkit-extension",
+            "executable+watch+bundle": "com.apple.product-type.application.watchapp",
+            "mac_kernel_extension+bundle": "com.apple.product-type.kernel-extension",
+        }
+
+        target_properties = {
+            "buildConfigurationList": xccl,
+            "name": target_name,
+        }
+
+        type = spec["type"]
+        is_xctest = int(spec.get("mac_xctest_bundle", 0))
+        is_xcuitest = int(spec.get("mac_xcuitest_bundle", 0))
+        is_bundle = int(spec.get("mac_bundle", 0)) or is_xctest
+        is_app_extension = int(spec.get("ios_app_extension", 0))
+        is_watchkit_extension = int(spec.get("ios_watchkit_extension", 0))
+        is_watch_app = int(spec.get("ios_watch_app", 0))
+        if type != "none":
+            type_bundle_key = type
+            if is_xcuitest:
+                type_bundle_key += "+xcuitest"
+                assert type == "loadable_module", (
+                    "mac_xcuitest_bundle targets must have type loadable_module "
+                    "(target %s)" % target_name
+                )
+            elif is_xctest:
+                type_bundle_key += "+xctest"
+                assert type == "loadable_module", (
+                    "mac_xctest_bundle targets must have type loadable_module "
+                    "(target %s)" % target_name
+                )
+            elif is_app_extension:
+                assert is_bundle, (
+                    "ios_app_extension flag requires mac_bundle "
+                    "(target %s)" % target_name
+                )
+                type_bundle_key += "+extension+bundle"
+            elif is_watchkit_extension:
+                assert is_bundle, (
+                    "ios_watchkit_extension flag requires mac_bundle "
+                    "(target %s)" % target_name
+                )
+                type_bundle_key += "+watch+extension+bundle"
+            elif is_watch_app:
+                assert is_bundle, (
+                    "ios_watch_app flag requires mac_bundle "
+                    "(target %s)" % target_name
+                )
+                type_bundle_key += "+watch+bundle"
+            elif is_bundle:
+                type_bundle_key += "+bundle"
+
+            xctarget_type = gyp.xcodeproj_file.PBXNativeTarget
+            try:
+                target_properties["productType"] = _types[type_bundle_key]
+            except KeyError as e:
+                gyp.common.ExceptionAppend(
+                    e,
+                    "-- unknown product type while " "writing target %s" % target_name,
+                )
+                raise
+        else:
+            xctarget_type = gyp.xcodeproj_file.PBXAggregateTarget
+            assert not is_bundle, (
+                'mac_bundle targets cannot have type none (target "%s")' % target_name
+            )
+            assert not is_xcuitest, (
+                'mac_xcuitest_bundle targets cannot have type none (target "%s")'
+                % target_name
+            )
+            assert not is_xctest, (
+                'mac_xctest_bundle targets cannot have type none (target "%s")'
+                % target_name
+            )
+
+        target_product_name = spec.get("product_name")
+        if target_product_name is not None:
+            target_properties["productName"] = target_product_name
+
+        xct = xctarget_type(
+            target_properties,
+            parent=pbxp,
+            force_outdir=spec.get("product_dir"),
+            force_prefix=spec.get("product_prefix"),
+            force_extension=spec.get("product_extension"),
+        )
+        pbxp.AppendProperty("targets", xct)
+        xcode_targets[qualified_target] = xct
+        xcode_target_to_target_dict[xct] = spec
+
+        spec_actions = spec.get("actions", [])
+        spec_rules = spec.get("rules", [])
+
+        # Xcode has some "issues" with checking dependencies for the "Compile
+        # sources" step with any source files/headers generated by actions/rules.
+        # To work around this, if a target is building anything directly (not
+        # type "none"), then a second target is used to run the GYP actions/rules
+        # and is made a dependency of this target.  This way the work is done
+        # before the dependency checks for what should be recompiled.
+        support_xct = None
+        # The Xcode "issues" don't affect xcode-ninja builds, since the dependency
+        # logic all happens in ninja.  Don't bother creating the extra targets in
+        # that case.
+        if type != "none" and (spec_actions or spec_rules) and not ninja_wrapper:
+            support_xccl = CreateXCConfigurationList(configuration_names)
+            support_target_suffix = generator_flags.get(
+                "support_target_suffix", " Support"
+            )
+            support_target_properties = {
+                "buildConfigurationList": support_xccl,
+                "name": target_name + support_target_suffix,
+            }
+            if target_product_name:
+                support_target_properties["productName"] = (
+                    target_product_name + " Support"
+                )
+            support_xct = gyp.xcodeproj_file.PBXAggregateTarget(
+                support_target_properties, parent=pbxp
+            )
+            pbxp.AppendProperty("targets", support_xct)
+            xct.AddDependency(support_xct)
+        # Hang the support target off the main target so it can be tested/found
+        # by the generator during Finalize.
+        xct.support_target = support_xct
+
+        prebuild_index = 0
+
+        # Add custom shell script phases for "actions" sections.
+        for action in spec_actions:
+            # There's no need to write anything into the script to ensure that the
+            # output directories already exist, because Xcode will look at the
+            # declared outputs and automatically ensure that they exist for us.
+
+            # Do we have a message to print when this action runs?
+            message = action.get("message")
+            if message:
+                message = "echo note: " + gyp.common.EncodePOSIXShellArgument(message)
+            else:
+                message = ""
+
+            # Turn the list into a string that can be passed to a shell.
+            action_string = gyp.common.EncodePOSIXShellList(action["action"])
+
+            # Convert Xcode-type variable references to sh-compatible environment
+            # variable references.
+            message_sh = gyp.xcodeproj_file.ConvertVariablesToShellSyntax(message)
+            action_string_sh = gyp.xcodeproj_file.ConvertVariablesToShellSyntax(
+                action_string
+            )
+
+            script = ""
+            # Include the optional message
+            if message_sh:
+                script += message_sh + "\n"
+            # Be sure the script runs in exec, and that if exec fails, the script
+            # exits signalling an error.
+            script += "exec " + action_string_sh + "\nexit 1\n"
+            ssbp = gyp.xcodeproj_file.PBXShellScriptBuildPhase(
+                {
+                    "inputPaths": action["inputs"],
+                    "name": 'Action "' + action["action_name"] + '"',
+                    "outputPaths": action["outputs"],
+                    "shellScript": script,
+                    "showEnvVarsInLog": 0,
+                }
+            )
+
+            if support_xct:
+                support_xct.AppendProperty("buildPhases", ssbp)
+            else:
+                # TODO(mark): this assumes too much knowledge of the internals of
+                # xcodeproj_file; some of these smarts should move into xcodeproj_file
+                # itself.
+                xct._properties["buildPhases"].insert(prebuild_index, ssbp)
+                prebuild_index = prebuild_index + 1
+
+            # TODO(mark): Should verify that at most one of these is specified.
+            if int(action.get("process_outputs_as_sources", False)):
+                for output in action["outputs"]:
+                    AddSourceToTarget(output, type, pbxp, xct)
+
+            if int(action.get("process_outputs_as_mac_bundle_resources", False)):
+                for output in action["outputs"]:
+                    AddResourceToTarget(output, pbxp, xct)
+
+        # tgt_mac_bundle_resources holds the list of bundle resources so
+        # the rule processing can check against it.
+        if is_bundle:
+            tgt_mac_bundle_resources = spec.get("mac_bundle_resources", [])
+        else:
+            tgt_mac_bundle_resources = []
+
+        # Add custom shell script phases driving "make" for "rules" sections.
+        #
+        # Xcode's built-in rule support is almost powerful enough to use directly,
+        # but there are a few significant deficiencies that render them unusable.
+        # There are workarounds for some of its inadequacies, but in aggregate,
+        # the workarounds added complexity to the generator, and some workarounds
+        # actually require input files to be crafted more carefully than I'd like.
+        # Consequently, until Xcode rules are made more capable, "rules" input
+        # sections will be handled in Xcode output by shell script build phases
+        # performed prior to the compilation phase.
+        #
+        # The following problems with Xcode rules were found.  The numbers are
+        # Apple radar IDs.  I hope that these shortcomings are addressed, I really
+        # liked having the rules handled directly in Xcode during the period that
+        # I was prototyping this.
+        #
+        # 6588600 Xcode compiles custom script rule outputs too soon, compilation
+        #         fails.  This occurs when rule outputs from distinct inputs are
+        #         interdependent.  The only workaround is to put rules and their
+        #         inputs in a separate target from the one that compiles the rule
+        #         outputs.  This requires input file cooperation and it means that
+        #         process_outputs_as_sources is unusable.
+        # 6584932 Need to declare that custom rule outputs should be excluded from
+        #         compilation.  A possible workaround is to lie to Xcode about a
+        #         rule's output, giving it a dummy file it doesn't know how to
+        #         compile.  The rule action script would need to touch the dummy.
+        # 6584839 I need a way to declare additional inputs to a custom rule.
+        #         A possible workaround is a shell script phase prior to
+        #         compilation that touches a rule's primary input files if any
+        #         would-be additional inputs are newer than the output.  Modifying
+        #         the source tree - even just modification times - feels dirty.
+        # 6564240 Xcode "custom script" build rules always dump all environment
+        #         variables.  This is a low-prioroty problem and is not a
+        #         show-stopper.
+        rules_by_ext = {}
+        for rule in spec_rules:
+            rules_by_ext[rule["extension"]] = rule
+
+            # First, some definitions:
+            #
+            # A "rule source" is a file that was listed in a target's "sources"
+            # list and will have a rule applied to it on the basis of matching the
+            # rule's "extensions" attribute.  Rule sources are direct inputs to
+            # rules.
+            #
+            # Rule definitions may specify additional inputs in their "inputs"
+            # attribute.  These additional inputs are used for dependency tracking
+            # purposes.
+            #
+            # A "concrete output" is a rule output with input-dependent variables
+            # resolved.  For example, given a rule with:
+            #   'extension': 'ext', 'outputs': ['$(INPUT_FILE_BASE).cc'],
+            # if the target's "sources" list contained "one.ext" and "two.ext",
+            # the "concrete output" for rule input "two.ext" would be "two.cc".  If
+            # a rule specifies multiple outputs, each input file that the rule is
+            # applied to will have the same number of concrete outputs.
+            #
+            # If any concrete outputs are outdated or missing relative to their
+            # corresponding rule_source or to any specified additional input, the
+            # rule action must be performed to generate the concrete outputs.
+
+            # concrete_outputs_by_rule_source will have an item at the same index
+            # as the rule['rule_sources'] that it corresponds to.  Each item is a
+            # list of all of the concrete outputs for the rule_source.
+            concrete_outputs_by_rule_source = []
+
+            # concrete_outputs_all is a flat list of all concrete outputs that this
+            # rule is able to produce, given the known set of input files
+            # (rule_sources) that apply to it.
+            concrete_outputs_all = []
+
+            # messages & actions are keyed by the same indices as rule['rule_sources']
+            # and concrete_outputs_by_rule_source.  They contain the message and
+            # action to perform after resolving input-dependent variables.  The
+            # message is optional, in which case None is stored for each rule source.
+            messages = []
+            actions = []
+
+            for rule_source in rule.get("rule_sources", []):
+                rule_source_dirname, rule_source_basename = posixpath.split(rule_source)
+                (rule_source_root, rule_source_ext) = posixpath.splitext(
+                    rule_source_basename
+                )
+
+                # These are the same variable names that Xcode uses for its own native
+                # rule support.  Because Xcode's rule engine is not being used, they
+                # need to be expanded as they are written to the makefile.
+                rule_input_dict = {
+                    "INPUT_FILE_BASE": rule_source_root,
+                    "INPUT_FILE_SUFFIX": rule_source_ext,
+                    "INPUT_FILE_NAME": rule_source_basename,
+                    "INPUT_FILE_PATH": rule_source,
+                    "INPUT_FILE_DIRNAME": rule_source_dirname,
+                }
+
+                concrete_outputs_for_this_rule_source = []
+                for output in rule.get("outputs", []):
+                    # Fortunately, Xcode and make both use $(VAR) format for their
+                    # variables, so the expansion is the only transformation necessary.
+                    # Any remaining $(VAR)-type variables in the string can be given
+                    # directly to make, which will pick up the correct settings from
+                    # what Xcode puts into the environment.
+                    concrete_output = ExpandXcodeVariables(output, rule_input_dict)
+                    concrete_outputs_for_this_rule_source.append(concrete_output)
+
+                    # Add all concrete outputs to the project.
+                    pbxp.AddOrGetFileInRootGroup(concrete_output)
+
+                concrete_outputs_by_rule_source.append(
+                    concrete_outputs_for_this_rule_source
+                )
+                concrete_outputs_all.extend(concrete_outputs_for_this_rule_source)
+
+                # TODO(mark): Should verify that at most one of these is specified.
+                if int(rule.get("process_outputs_as_sources", False)):
+                    for output in concrete_outputs_for_this_rule_source:
+                        AddSourceToTarget(output, type, pbxp, xct)
+
+                # If the file came from the mac_bundle_resources list or if the rule
+                # is marked to process outputs as bundle resource, do so.
+                was_mac_bundle_resource = rule_source in tgt_mac_bundle_resources
+                if was_mac_bundle_resource or int(
+                    rule.get("process_outputs_as_mac_bundle_resources", False)
+                ):
+                    for output in concrete_outputs_for_this_rule_source:
+                        AddResourceToTarget(output, pbxp, xct)
+
+                # Do we have a message to print when this rule runs?
+                message = rule.get("message")
+                if message:
+                    message = gyp.common.EncodePOSIXShellArgument(message)
+                    message = ExpandXcodeVariables(message, rule_input_dict)
+                messages.append(message)
+
+                # Turn the list into a string that can be passed to a shell.
+                action_string = gyp.common.EncodePOSIXShellList(rule["action"])
+
+                action = ExpandXcodeVariables(action_string, rule_input_dict)
+                actions.append(action)
+
+            if len(concrete_outputs_all) > 0:
+                # TODO(mark): There's a possibility for collision here.  Consider
+                # target "t" rule "A_r" and target "t_A" rule "r".
+                makefile_name = "%s.make" % re.sub(
+                    "[^a-zA-Z0-9_]", "_", "{}_{}".format(target_name, rule["rule_name"])
+                )
+                makefile_path = os.path.join(
+                    xcode_projects[build_file].path, makefile_name
+                )
+                # TODO(mark): try/close?  Write to a temporary file and swap it only
+                # if it's got changes?
+                makefile = open(makefile_path, "w")
+
+                # make will build the first target in the makefile by default.  By
+                # convention, it's called "all".  List all (or at least one)
+                # concrete output for each rule source as a prerequisite of the "all"
+                # target.
+                makefile.write("all: \\\n")
+                for concrete_output_index, concrete_output_by_rule_source in enumerate(
+                    concrete_outputs_by_rule_source
+                ):
+                    # Only list the first (index [0]) concrete output of each input
+                    # in the "all" target.  Otherwise, a parallel make (-j > 1) would
+                    # attempt to process each input multiple times simultaneously.
+                    # Otherwise, "all" could just contain the entire list of
+                    # concrete_outputs_all.
+                    concrete_output = concrete_output_by_rule_source[0]
+                    if (
+                        concrete_output_index
+                        == len(concrete_outputs_by_rule_source) - 1
+                    ):
+                        eol = ""
+                    else:
+                        eol = " \\"
+                    makefile.write(f"    {concrete_output}{eol}\n")
+
+                for (rule_source, concrete_outputs, message, action) in zip(
+                    rule["rule_sources"],
+                    concrete_outputs_by_rule_source,
+                    messages,
+                    actions,
+                ):
+                    makefile.write("\n")
+
+                    # Add a rule that declares it can build each concrete output of a
+                    # rule source.  Collect the names of the directories that are
+                    # required.
+                    concrete_output_dirs = []
+                    for concrete_output_index, concrete_output in enumerate(
+                        concrete_outputs
+                    ):
+                        if concrete_output_index == 0:
+                            bol = ""
+                        else:
+                            bol = "    "
+                        makefile.write(f"{bol}{concrete_output} \\\n")
+
+                        concrete_output_dir = posixpath.dirname(concrete_output)
+                        if (
+                            concrete_output_dir
+                            and concrete_output_dir not in concrete_output_dirs
+                        ):
+                            concrete_output_dirs.append(concrete_output_dir)
+
+                    makefile.write("    : \\\n")
+
+                    # The prerequisites for this rule are the rule source itself and
+                    # the set of additional rule inputs, if any.
+                    prerequisites = [rule_source]
+                    prerequisites.extend(rule.get("inputs", []))
+                    for prerequisite_index, prerequisite in enumerate(prerequisites):
+                        if prerequisite_index == len(prerequisites) - 1:
+                            eol = ""
+                        else:
+                            eol = " \\"
+                        makefile.write(f"    {prerequisite}{eol}\n")
+
+                    # Make sure that output directories exist before executing the rule
+                    # action.
+                    if len(concrete_output_dirs) > 0:
+                        makefile.write(
+                            '\t@mkdir -p "%s"\n' % '" "'.join(concrete_output_dirs)
+                        )
+
+                    # The rule message and action have already had
+                    # the necessary variable substitutions performed.
+                    if message:
+                        # Mark it with note: so Xcode picks it up in build output.
+                        makefile.write("\t@echo note: %s\n" % message)
+                    makefile.write("\t%s\n" % action)
+
+                makefile.close()
+
+                # It might be nice to ensure that needed output directories exist
+                # here rather than in each target in the Makefile, but that wouldn't
+                # work if there ever was a concrete output that had an input-dependent
+                # variable anywhere other than in the leaf position.
+
+                # Don't declare any inputPaths or outputPaths.  If they're present,
+                # Xcode will provide a slight optimization by only running the script
+                # phase if any output is missing or outdated relative to any input.
+                # Unfortunately, it will also assume that all outputs are touched by
+                # the script, and if the outputs serve as files in a compilation
+                # phase, they will be unconditionally rebuilt.  Since make might not
+                # rebuild everything that could be declared here as an output, this
+                # extra compilation activity is unnecessary.  With inputPaths and
+                # outputPaths not supplied, make will always be called, but it knows
+                # enough to not do anything when everything is up-to-date.
+
+                # To help speed things up, pass -j COUNT to make so it does some work
+                # in parallel.  Don't use ncpus because Xcode will build ncpus targets
+                # in parallel and if each target happens to have a rules step, there
+                # would be ncpus^2 things going.  With a machine that has 2 quad-core
+                # Xeons, a build can quickly run out of processes based on
+                # scheduling/other tasks, and randomly failing builds are no good.
+                script = (
+                    """JOB_COUNT="$(/usr/sbin/sysctl -n hw.ncpu)"
+if [ "${JOB_COUNT}" -gt 4 ]; then
+  JOB_COUNT=4
+fi
+exec xcrun make -f "${PROJECT_FILE_PATH}/%s" -j "${JOB_COUNT}"
+exit 1
+"""
+                    % makefile_name
+                )
+                ssbp = gyp.xcodeproj_file.PBXShellScriptBuildPhase(
+                    {
+                        "name": 'Rule "' + rule["rule_name"] + '"',
+                        "shellScript": script,
+                        "showEnvVarsInLog": 0,
+                    }
+                )
+
+                if support_xct:
+                    support_xct.AppendProperty("buildPhases", ssbp)
+                else:
+                    # TODO(mark): this assumes too much knowledge of the internals of
+                    # xcodeproj_file; some of these smarts should move
+                    # into xcodeproj_file itself.
+                    xct._properties["buildPhases"].insert(prebuild_index, ssbp)
+                    prebuild_index = prebuild_index + 1
+
+            # Extra rule inputs also go into the project file.  Concrete outputs were
+            # already added when they were computed.
+            groups = ["inputs", "inputs_excluded"]
+            if skip_excluded_files:
+                groups = [x for x in groups if not x.endswith("_excluded")]
+            for group in groups:
+                for item in rule.get(group, []):
+                    pbxp.AddOrGetFileInRootGroup(item)
+
+        # Add "sources".
+        for source in spec.get("sources", []):
+            (source_root, source_extension) = posixpath.splitext(source)
+            if source_extension[1:] not in rules_by_ext:
+                # AddSourceToTarget will add the file to a root group if it's not
+                # already there.
+                AddSourceToTarget(source, type, pbxp, xct)
+            else:
+                pbxp.AddOrGetFileInRootGroup(source)
+
+        # Add "mac_bundle_resources" and "mac_framework_private_headers" if
+        # it's a bundle of any type.
+        if is_bundle:
+            for resource in tgt_mac_bundle_resources:
+                (resource_root, resource_extension) = posixpath.splitext(resource)
+                if resource_extension[1:] not in rules_by_ext:
+                    AddResourceToTarget(resource, pbxp, xct)
+                else:
+                    pbxp.AddOrGetFileInRootGroup(resource)
+
+            for header in spec.get("mac_framework_private_headers", []):
+                AddHeaderToTarget(header, pbxp, xct, False)
+
+        # Add "mac_framework_headers". These can be valid for both frameworks
+        # and static libraries.
+        if is_bundle or type == "static_library":
+            for header in spec.get("mac_framework_headers", []):
+                AddHeaderToTarget(header, pbxp, xct, True)
+
+        # Add "copies".
+        pbxcp_dict = {}
+        for copy_group in spec.get("copies", []):
+            dest = copy_group["destination"]
+            if dest[0] not in ("/", "$"):
+                # Relative paths are relative to $(SRCROOT).
+                dest = "$(SRCROOT)/" + dest
+
+            code_sign = int(copy_group.get("xcode_code_sign", 0))
+            settings = (None, "{ATTRIBUTES = (CodeSignOnCopy, ); }")[code_sign]
+
+            # Coalesce multiple "copies" sections in the same target with the same
+            # "destination" property into the same PBXCopyFilesBuildPhase, otherwise
+            # they'll wind up with ID collisions.
+            pbxcp = pbxcp_dict.get(dest, None)
+            if pbxcp is None:
+                pbxcp = gyp.xcodeproj_file.PBXCopyFilesBuildPhase(
+                    {"name": "Copy to " + copy_group["destination"]}, parent=xct
+                )
+                pbxcp.SetDestination(dest)
+
+                # TODO(mark): The usual comment about this knowing too much about
+                # gyp.xcodeproj_file internals applies.
+                xct._properties["buildPhases"].insert(prebuild_index, pbxcp)
+
+                pbxcp_dict[dest] = pbxcp
+
+            for file in copy_group["files"]:
+                pbxcp.AddFile(file, settings)
+
+        # Excluded files can also go into the project file.
+        if not skip_excluded_files:
+            for key in [
+                "sources",
+                "mac_bundle_resources",
+                "mac_framework_headers",
+                "mac_framework_private_headers",
+            ]:
+                excluded_key = key + "_excluded"
+                for item in spec.get(excluded_key, []):
+                    pbxp.AddOrGetFileInRootGroup(item)
+
+        # So can "inputs" and "outputs" sections of "actions" groups.
+        groups = ["inputs", "inputs_excluded", "outputs", "outputs_excluded"]
+        if skip_excluded_files:
+            groups = [x for x in groups if not x.endswith("_excluded")]
+        for action in spec.get("actions", []):
+            for group in groups:
+                for item in action.get(group, []):
+                    # Exclude anything in BUILT_PRODUCTS_DIR.  They're products, not
+                    # sources.
+                    if not item.startswith("$(BUILT_PRODUCTS_DIR)/"):
+                        pbxp.AddOrGetFileInRootGroup(item)
+
+        for postbuild in spec.get("postbuilds", []):
+            action_string_sh = gyp.common.EncodePOSIXShellList(postbuild["action"])
+            script = "exec " + action_string_sh + "\nexit 1\n"
+
+            # Make the postbuild step depend on the output of ld or ar from this
+            # target. Apparently putting the script step after the link step isn't
+            # sufficient to ensure proper ordering in all cases. With an input
+            # declared but no outputs, the script step should run every time, as
+            # desired.
+            ssbp = gyp.xcodeproj_file.PBXShellScriptBuildPhase(
+                {
+                    "inputPaths": ["$(BUILT_PRODUCTS_DIR)/$(EXECUTABLE_PATH)"],
+                    "name": 'Postbuild "' + postbuild["postbuild_name"] + '"',
+                    "shellScript": script,
+                    "showEnvVarsInLog": 0,
+                }
+            )
+            xct.AppendProperty("buildPhases", ssbp)
+
+        # Add dependencies before libraries, because adding a dependency may imply
+        # adding a library.  It's preferable to keep dependencies listed first
+        # during a link phase so that they can override symbols that would
+        # otherwise be provided by libraries, which will usually include system
+        # libraries.  On some systems, ld is finicky and even requires the
+        # libraries to be ordered in such a way that unresolved symbols in
+        # earlier-listed libraries may only be resolved by later-listed libraries.
+        # The Mac linker doesn't work that way, but other platforms do, and so
+        # their linker invocations need to be constructed in this way.  There's
+        # no compelling reason for Xcode's linker invocations to differ.
+
+        if "dependencies" in spec:
+            for dependency in spec["dependencies"]:
+                xct.AddDependency(xcode_targets[dependency])
+                # The support project also gets the dependencies (in case they are
+                # needed for the actions/rules to work).
+                if support_xct:
+                    support_xct.AddDependency(xcode_targets[dependency])
+
+        if "libraries" in spec:
+            for library in spec["libraries"]:
+                xct.FrameworksPhase().AddFile(library)
+                # Add the library's directory to LIBRARY_SEARCH_PATHS if necessary.
+                # I wish Xcode handled this automatically.
+                library_dir = posixpath.dirname(library)
+                if library_dir not in xcode_standard_library_dirs and (
+                    not xct.HasBuildSetting(_library_search_paths_var)
+                    or library_dir not in xct.GetBuildSetting(_library_search_paths_var)
+                ):
+                    xct.AppendBuildSetting(_library_search_paths_var, library_dir)
+
+        for configuration_name in configuration_names:
+            configuration = spec["configurations"][configuration_name]
+            xcbc = xct.ConfigurationNamed(configuration_name)
+            for include_dir in configuration.get("mac_framework_dirs", []):
+                xcbc.AppendBuildSetting("FRAMEWORK_SEARCH_PATHS", include_dir)
+            for include_dir in configuration.get("include_dirs", []):
+                xcbc.AppendBuildSetting("HEADER_SEARCH_PATHS", include_dir)
+            for library_dir in configuration.get("library_dirs", []):
+                if library_dir not in xcode_standard_library_dirs and (
+                    not xcbc.HasBuildSetting(_library_search_paths_var)
+                    or library_dir
+                    not in xcbc.GetBuildSetting(_library_search_paths_var)
+                ):
+                    xcbc.AppendBuildSetting(_library_search_paths_var, library_dir)
+
+            if "defines" in configuration:
+                for define in configuration["defines"]:
+                    set_define = EscapeXcodeDefine(define)
+                    xcbc.AppendBuildSetting("GCC_PREPROCESSOR_DEFINITIONS", set_define)
+            if "xcode_settings" in configuration:
+                for xck, xcv in configuration["xcode_settings"].items():
+                    xcbc.SetBuildSetting(xck, xcv)
+            if "xcode_config_file" in configuration:
+                config_ref = pbxp.AddOrGetFileInRootGroup(
+                    configuration["xcode_config_file"]
+                )
+                xcbc.SetBaseConfiguration(config_ref)
+
+    build_files = []
+    for build_file, build_file_dict in data.items():
+        if build_file.endswith(".gyp"):
+            build_files.append(build_file)
+
+    for build_file in build_files:
+        xcode_projects[build_file].Finalize1(xcode_targets, serialize_all_tests)
+
+    for build_file in build_files:
+        xcode_projects[build_file].Finalize2(xcode_targets, xcode_target_to_target_dict)
+
+    for build_file in build_files:
+        xcode_projects[build_file].Write()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/generator/xcode_test.py b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/xcode_test.py
new file mode 100644
index 0000000..49772d1
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/generator/xcode_test.py
@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2013 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+""" Unit tests for the xcode.py file. """
+
+import gyp.generator.xcode as xcode
+import unittest
+import sys
+
+
+class TestEscapeXcodeDefine(unittest.TestCase):
+    if sys.platform == "darwin":
+
+        def test_InheritedRemainsUnescaped(self):
+            self.assertEqual(xcode.EscapeXcodeDefine("$(inherited)"), "$(inherited)")
+
+        def test_Escaping(self):
+            self.assertEqual(xcode.EscapeXcodeDefine('a b"c\\'), 'a\\ b\\"c\\\\')
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/input.py b/server/node_modules/node-gyp/gyp/pylib/gyp/input.py
new file mode 100644
index 0000000..354958b
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/input.py
@@ -0,0 +1,3137 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+import ast
+
+import gyp.common
+import gyp.simple_copy
+import multiprocessing
+import os.path
+import re
+import shlex
+import signal
+import subprocess
+import sys
+import threading
+import traceback
+from distutils.version import StrictVersion
+from gyp.common import GypError
+from gyp.common import OrderedSet
+
+# A list of types that are treated as linkable.
+linkable_types = [
+    "executable",
+    "shared_library",
+    "loadable_module",
+    "mac_kernel_extension",
+    "windows_driver",
+]
+
+# A list of sections that contain links to other targets.
+dependency_sections = ["dependencies", "export_dependent_settings"]
+
+# base_path_sections is a list of sections defined by GYP that contain
+# pathnames.  The generators can provide more keys, the two lists are merged
+# into path_sections, but you should call IsPathSection instead of using either
+# list directly.
+base_path_sections = [
+    "destination",
+    "files",
+    "include_dirs",
+    "inputs",
+    "libraries",
+    "outputs",
+    "sources",
+]
+path_sections = set()
+
+# These per-process dictionaries are used to cache build file data when loading
+# in parallel mode.
+per_process_data = {}
+per_process_aux_data = {}
+
+
+def IsPathSection(section):
+    # If section ends in one of the '=+?!' characters, it's applied to a section
+    # without the trailing characters.  '/' is notably absent from this list,
+    # because there's no way for a regular expression to be treated as a path.
+    while section and section[-1:] in "=+?!":
+        section = section[:-1]
+
+    if section in path_sections:
+        return True
+
+    # Sections matching the regexp '_(dir|file|path)s?$' are also
+    # considered PathSections. Using manual string matching since that
+    # is much faster than the regexp and this can be called hundreds of
+    # thousands of times so micro performance matters.
+    if "_" in section:
+        tail = section[-6:]
+        if tail[-1] == "s":
+            tail = tail[:-1]
+        if tail[-5:] in ("_file", "_path"):
+            return True
+        return tail[-4:] == "_dir"
+
+    return False
+
+
+# base_non_configuration_keys is a list of key names that belong in the target
+# itself and should not be propagated into its configurations.  It is merged
+# with a list that can come from the generator to
+# create non_configuration_keys.
+base_non_configuration_keys = [
+    # Sections that must exist inside targets and not configurations.
+    "actions",
+    "configurations",
+    "copies",
+    "default_configuration",
+    "dependencies",
+    "dependencies_original",
+    "libraries",
+    "postbuilds",
+    "product_dir",
+    "product_extension",
+    "product_name",
+    "product_prefix",
+    "rules",
+    "run_as",
+    "sources",
+    "standalone_static_library",
+    "suppress_wildcard",
+    "target_name",
+    "toolset",
+    "toolsets",
+    "type",
+    # Sections that can be found inside targets or configurations, but that
+    # should not be propagated from targets into their configurations.
+    "variables",
+]
+non_configuration_keys = []
+
+# Keys that do not belong inside a configuration dictionary.
+invalid_configuration_keys = [
+    "actions",
+    "all_dependent_settings",
+    "configurations",
+    "dependencies",
+    "direct_dependent_settings",
+    "libraries",
+    "link_settings",
+    "sources",
+    "standalone_static_library",
+    "target_name",
+    "type",
+]
+
+# Controls whether or not the generator supports multiple toolsets.
+multiple_toolsets = False
+
+# Paths for converting filelist paths to output paths: {
+#   toplevel,
+#   qualified_output_dir,
+# }
+generator_filelist_paths = None
+
+
+def GetIncludedBuildFiles(build_file_path, aux_data, included=None):
+    """Return a list of all build files included into build_file_path.
+
+  The returned list will contain build_file_path as well as all other files
+  that it included, either directly or indirectly.  Note that the list may
+  contain files that were included into a conditional section that evaluated
+  to false and was not merged into build_file_path's dict.
+
+  aux_data is a dict containing a key for each build file or included build
+  file.  Those keys provide access to dicts whose "included" keys contain
+  lists of all other files included by the build file.
+
+  included should be left at its default None value by external callers.  It
+  is used for recursion.
+
+  The returned list will not contain any duplicate entries.  Each build file
+  in the list will be relative to the current directory.
+  """
+
+    if included is None:
+        included = []
+
+    if build_file_path in included:
+        return included
+
+    included.append(build_file_path)
+
+    for included_build_file in aux_data[build_file_path].get("included", []):
+        GetIncludedBuildFiles(included_build_file, aux_data, included)
+
+    return included
+
+
+def CheckedEval(file_contents):
+    """Return the eval of a gyp file.
+  The gyp file is restricted to dictionaries and lists only, and
+  repeated keys are not allowed.
+  Note that this is slower than eval() is.
+  """
+
+    syntax_tree = ast.parse(file_contents)
+    assert isinstance(syntax_tree, ast.Module)
+    c1 = syntax_tree.body
+    assert len(c1) == 1
+    c2 = c1[0]
+    assert isinstance(c2, ast.Expr)
+    return CheckNode(c2.value, [])
+
+
+def CheckNode(node, keypath):
+    if isinstance(node, ast.Dict):
+        dict = {}
+        for key, value in zip(node.keys, node.values):
+            assert isinstance(key, ast.Str)
+            key = key.s
+            if key in dict:
+                raise GypError(
+                    "Key '"
+                    + key
+                    + "' repeated at level "
+                    + repr(len(keypath) + 1)
+                    + " with key path '"
+                    + ".".join(keypath)
+                    + "'"
+                )
+            kp = list(keypath)  # Make a copy of the list for descending this node.
+            kp.append(key)
+            dict[key] = CheckNode(value, kp)
+        return dict
+    elif isinstance(node, ast.List):
+        children = []
+        for index, child in enumerate(node.elts):
+            kp = list(keypath)  # Copy list.
+            kp.append(repr(index))
+            children.append(CheckNode(child, kp))
+        return children
+    elif isinstance(node, ast.Str):
+        return node.s
+    else:
+        raise TypeError(
+            "Unknown AST node at key path '" + ".".join(keypath) + "': " + repr(node)
+        )
+
+
+def LoadOneBuildFile(build_file_path, data, aux_data, includes, is_target, check):
+    if build_file_path in data:
+        return data[build_file_path]
+
+    if os.path.exists(build_file_path):
+        build_file_contents = open(build_file_path, encoding='utf-8').read()
+    else:
+        raise GypError(f"{build_file_path} not found (cwd: {os.getcwd()})")
+
+    build_file_data = None
+    try:
+        if check:
+            build_file_data = CheckedEval(build_file_contents)
+        else:
+            build_file_data = eval(build_file_contents, {"__builtins__": {}}, None)
+    except SyntaxError as e:
+        e.filename = build_file_path
+        raise
+    except Exception as e:
+        gyp.common.ExceptionAppend(e, "while reading " + build_file_path)
+        raise
+
+    if type(build_file_data) is not dict:
+        raise GypError("%s does not evaluate to a dictionary." % build_file_path)
+
+    data[build_file_path] = build_file_data
+    aux_data[build_file_path] = {}
+
+    # Scan for includes and merge them in.
+    if "skip_includes" not in build_file_data or not build_file_data["skip_includes"]:
+        try:
+            if is_target:
+                LoadBuildFileIncludesIntoDict(
+                    build_file_data, build_file_path, data, aux_data, includes, check
+                )
+            else:
+                LoadBuildFileIncludesIntoDict(
+                    build_file_data, build_file_path, data, aux_data, None, check
+                )
+        except Exception as e:
+            gyp.common.ExceptionAppend(
+                e, "while reading includes of " + build_file_path
+            )
+            raise
+
+    return build_file_data
+
+
+def LoadBuildFileIncludesIntoDict(
+    subdict, subdict_path, data, aux_data, includes, check
+):
+    includes_list = []
+    if includes is not None:
+        includes_list.extend(includes)
+    if "includes" in subdict:
+        for include in subdict["includes"]:
+            # "include" is specified relative to subdict_path, so compute the real
+            # path to include by appending the provided "include" to the directory
+            # in which subdict_path resides.
+            relative_include = os.path.normpath(
+                os.path.join(os.path.dirname(subdict_path), include)
+            )
+            includes_list.append(relative_include)
+        # Unhook the includes list, it's no longer needed.
+        del subdict["includes"]
+
+    # Merge in the included files.
+    for include in includes_list:
+        if "included" not in aux_data[subdict_path]:
+            aux_data[subdict_path]["included"] = []
+        aux_data[subdict_path]["included"].append(include)
+
+        gyp.DebugOutput(gyp.DEBUG_INCLUDES, "Loading Included File: '%s'", include)
+
+        MergeDicts(
+            subdict,
+            LoadOneBuildFile(include, data, aux_data, None, False, check),
+            subdict_path,
+            include,
+        )
+
+    # Recurse into subdictionaries.
+    for k, v in subdict.items():
+        if type(v) is dict:
+            LoadBuildFileIncludesIntoDict(v, subdict_path, data, aux_data, None, check)
+        elif type(v) is list:
+            LoadBuildFileIncludesIntoList(v, subdict_path, data, aux_data, check)
+
+
+# This recurses into lists so that it can look for dicts.
+def LoadBuildFileIncludesIntoList(sublist, sublist_path, data, aux_data, check):
+    for item in sublist:
+        if type(item) is dict:
+            LoadBuildFileIncludesIntoDict(
+                item, sublist_path, data, aux_data, None, check
+            )
+        elif type(item) is list:
+            LoadBuildFileIncludesIntoList(item, sublist_path, data, aux_data, check)
+
+
+# Processes toolsets in all the targets. This recurses into condition entries
+# since they can contain toolsets as well.
+def ProcessToolsetsInDict(data):
+    if "targets" in data:
+        target_list = data["targets"]
+        new_target_list = []
+        for target in target_list:
+            # If this target already has an explicit 'toolset', and no 'toolsets'
+            # list, don't modify it further.
+            if "toolset" in target and "toolsets" not in target:
+                new_target_list.append(target)
+                continue
+            if multiple_toolsets:
+                toolsets = target.get("toolsets", ["target"])
+            else:
+                toolsets = ["target"]
+            # Make sure this 'toolsets' definition is only processed once.
+            if "toolsets" in target:
+                del target["toolsets"]
+            if len(toolsets) > 0:
+                # Optimization: only do copies if more than one toolset is specified.
+                for build in toolsets[1:]:
+                    new_target = gyp.simple_copy.deepcopy(target)
+                    new_target["toolset"] = build
+                    new_target_list.append(new_target)
+                target["toolset"] = toolsets[0]
+                new_target_list.append(target)
+        data["targets"] = new_target_list
+    if "conditions" in data:
+        for condition in data["conditions"]:
+            if type(condition) is list:
+                for condition_dict in condition[1:]:
+                    if type(condition_dict) is dict:
+                        ProcessToolsetsInDict(condition_dict)
+
+
+# TODO(mark): I don't love this name.  It just means that it's going to load
+# a build file that contains targets and is expected to provide a targets dict
+# that contains the targets...
+def LoadTargetBuildFile(
+    build_file_path,
+    data,
+    aux_data,
+    variables,
+    includes,
+    depth,
+    check,
+    load_dependencies,
+):
+    # If depth is set, predefine the DEPTH variable to be a relative path from
+    # this build file's directory to the directory identified by depth.
+    if depth:
+        # TODO(dglazkov) The backslash/forward-slash replacement at the end is a
+        # temporary measure. This should really be addressed by keeping all paths
+        # in POSIX until actual project generation.
+        d = gyp.common.RelativePath(depth, os.path.dirname(build_file_path))
+        if d == "":
+            variables["DEPTH"] = "."
+        else:
+            variables["DEPTH"] = d.replace("\\", "/")
+
+    # The 'target_build_files' key is only set when loading target build files in
+    # the non-parallel code path, where LoadTargetBuildFile is called
+    # recursively.  In the parallel code path, we don't need to check whether the
+    # |build_file_path| has already been loaded, because the 'scheduled' set in
+    # ParallelState guarantees that we never load the same |build_file_path|
+    # twice.
+    if "target_build_files" in data:
+        if build_file_path in data["target_build_files"]:
+            # Already loaded.
+            return False
+        data["target_build_files"].add(build_file_path)
+
+    gyp.DebugOutput(
+        gyp.DEBUG_INCLUDES, "Loading Target Build File '%s'", build_file_path
+    )
+
+    build_file_data = LoadOneBuildFile(
+        build_file_path, data, aux_data, includes, True, check
+    )
+
+    # Store DEPTH for later use in generators.
+    build_file_data["_DEPTH"] = depth
+
+    # Set up the included_files key indicating which .gyp files contributed to
+    # this target dict.
+    if "included_files" in build_file_data:
+        raise GypError(build_file_path + " must not contain included_files key")
+
+    included = GetIncludedBuildFiles(build_file_path, aux_data)
+    build_file_data["included_files"] = []
+    for included_file in included:
+        # included_file is relative to the current directory, but it needs to
+        # be made relative to build_file_path's directory.
+        included_relative = gyp.common.RelativePath(
+            included_file, os.path.dirname(build_file_path)
+        )
+        build_file_data["included_files"].append(included_relative)
+
+    # Do a first round of toolsets expansion so that conditions can be defined
+    # per toolset.
+    ProcessToolsetsInDict(build_file_data)
+
+    # Apply "pre"/"early" variable expansions and condition evaluations.
+    ProcessVariablesAndConditionsInDict(
+        build_file_data, PHASE_EARLY, variables, build_file_path
+    )
+
+    # Since some toolsets might have been defined conditionally, perform
+    # a second round of toolsets expansion now.
+    ProcessToolsetsInDict(build_file_data)
+
+    # Look at each project's target_defaults dict, and merge settings into
+    # targets.
+    if "target_defaults" in build_file_data:
+        if "targets" not in build_file_data:
+            raise GypError("Unable to find targets in build file %s" % build_file_path)
+
+        index = 0
+        while index < len(build_file_data["targets"]):
+            # This procedure needs to give the impression that target_defaults is
+            # used as defaults, and the individual targets inherit from that.
+            # The individual targets need to be merged into the defaults.  Make
+            # a deep copy of the defaults for each target, merge the target dict
+            # as found in the input file into that copy, and then hook up the
+            # copy with the target-specific data merged into it as the replacement
+            # target dict.
+            old_target_dict = build_file_data["targets"][index]
+            new_target_dict = gyp.simple_copy.deepcopy(
+                build_file_data["target_defaults"]
+            )
+            MergeDicts(
+                new_target_dict, old_target_dict, build_file_path, build_file_path
+            )
+            build_file_data["targets"][index] = new_target_dict
+            index += 1
+
+        # No longer needed.
+        del build_file_data["target_defaults"]
+
+    # Look for dependencies.  This means that dependency resolution occurs
+    # after "pre" conditionals and variable expansion, but before "post" -
+    # in other words, you can't put a "dependencies" section inside a "post"
+    # conditional within a target.
+
+    dependencies = []
+    if "targets" in build_file_data:
+        for target_dict in build_file_data["targets"]:
+            if "dependencies" not in target_dict:
+                continue
+            for dependency in target_dict["dependencies"]:
+                dependencies.append(
+                    gyp.common.ResolveTarget(build_file_path, dependency, None)[0]
+                )
+
+    if load_dependencies:
+        for dependency in dependencies:
+            try:
+                LoadTargetBuildFile(
+                    dependency,
+                    data,
+                    aux_data,
+                    variables,
+                    includes,
+                    depth,
+                    check,
+                    load_dependencies,
+                )
+            except Exception as e:
+                gyp.common.ExceptionAppend(
+                    e, "while loading dependencies of %s" % build_file_path
+                )
+                raise
+    else:
+        return (build_file_path, dependencies)
+
+
+def CallLoadTargetBuildFile(
+    global_flags,
+    build_file_path,
+    variables,
+    includes,
+    depth,
+    check,
+    generator_input_info,
+):
+    """Wrapper around LoadTargetBuildFile for parallel processing.
+
+     This wrapper is used when LoadTargetBuildFile is executed in
+     a worker process.
+  """
+
+    try:
+        signal.signal(signal.SIGINT, signal.SIG_IGN)
+
+        # Apply globals so that the worker process behaves the same.
+        for key, value in global_flags.items():
+            globals()[key] = value
+
+        SetGeneratorGlobals(generator_input_info)
+        result = LoadTargetBuildFile(
+            build_file_path,
+            per_process_data,
+            per_process_aux_data,
+            variables,
+            includes,
+            depth,
+            check,
+            False,
+        )
+        if not result:
+            return result
+
+        (build_file_path, dependencies) = result
+
+        # We can safely pop the build_file_data from per_process_data because it
+        # will never be referenced by this process again, so we don't need to keep
+        # it in the cache.
+        build_file_data = per_process_data.pop(build_file_path)
+
+        # This gets serialized and sent back to the main process via a pipe.
+        # It's handled in LoadTargetBuildFileCallback.
+        return (build_file_path, build_file_data, dependencies)
+    except GypError as e:
+        sys.stderr.write("gyp: %s\n" % e)
+        return None
+    except Exception as e:
+        print("Exception:", e, file=sys.stderr)
+        print(traceback.format_exc(), file=sys.stderr)
+        return None
+
+
+class ParallelProcessingError(Exception):
+    pass
+
+
+class ParallelState:
+    """Class to keep track of state when processing input files in parallel.
+
+  If build files are loaded in parallel, use this to keep track of
+  state during farming out and processing parallel jobs. It's stored
+  in a global so that the callback function can have access to it.
+  """
+
+    def __init__(self):
+        # The multiprocessing pool.
+        self.pool = None
+        # The condition variable used to protect this object and notify
+        # the main loop when there might be more data to process.
+        self.condition = None
+        # The "data" dict that was passed to LoadTargetBuildFileParallel
+        self.data = None
+        # The number of parallel calls outstanding; decremented when a response
+        # was received.
+        self.pending = 0
+        # The set of all build files that have been scheduled, so we don't
+        # schedule the same one twice.
+        self.scheduled = set()
+        # A list of dependency build file paths that haven't been scheduled yet.
+        self.dependencies = []
+        # Flag to indicate if there was an error in a child process.
+        self.error = False
+
+    def LoadTargetBuildFileCallback(self, result):
+        """Handle the results of running LoadTargetBuildFile in another process.
+    """
+        self.condition.acquire()
+        if not result:
+            self.error = True
+            self.condition.notify()
+            self.condition.release()
+            return
+        (build_file_path0, build_file_data0, dependencies0) = result
+        self.data[build_file_path0] = build_file_data0
+        self.data["target_build_files"].add(build_file_path0)
+        for new_dependency in dependencies0:
+            if new_dependency not in self.scheduled:
+                self.scheduled.add(new_dependency)
+                self.dependencies.append(new_dependency)
+        self.pending -= 1
+        self.condition.notify()
+        self.condition.release()
+
+
+def LoadTargetBuildFilesParallel(
+    build_files, data, variables, includes, depth, check, generator_input_info
+):
+    parallel_state = ParallelState()
+    parallel_state.condition = threading.Condition()
+    # Make copies of the build_files argument that we can modify while working.
+    parallel_state.dependencies = list(build_files)
+    parallel_state.scheduled = set(build_files)
+    parallel_state.pending = 0
+    parallel_state.data = data
+
+    try:
+        parallel_state.condition.acquire()
+        while parallel_state.dependencies or parallel_state.pending:
+            if parallel_state.error:
+                break
+            if not parallel_state.dependencies:
+                parallel_state.condition.wait()
+                continue
+
+            dependency = parallel_state.dependencies.pop()
+
+            parallel_state.pending += 1
+            global_flags = {
+                "path_sections": globals()["path_sections"],
+                "non_configuration_keys": globals()["non_configuration_keys"],
+                "multiple_toolsets": globals()["multiple_toolsets"],
+            }
+
+            if not parallel_state.pool:
+                parallel_state.pool = multiprocessing.Pool(multiprocessing.cpu_count())
+            parallel_state.pool.apply_async(
+                CallLoadTargetBuildFile,
+                args=(
+                    global_flags,
+                    dependency,
+                    variables,
+                    includes,
+                    depth,
+                    check,
+                    generator_input_info,
+                ),
+                callback=parallel_state.LoadTargetBuildFileCallback,
+            )
+    except KeyboardInterrupt as e:
+        parallel_state.pool.terminate()
+        raise e
+
+    parallel_state.condition.release()
+
+    parallel_state.pool.close()
+    parallel_state.pool.join()
+    parallel_state.pool = None
+
+    if parallel_state.error:
+        sys.exit(1)
+
+
+# Look for the bracket that matches the first bracket seen in a
+# string, and return the start and end as a tuple.  For example, if
+# the input is something like "<(foo <(bar)) blah", then it would
+# return (1, 13), indicating the entire string except for the leading
+# "<" and trailing " blah".
+LBRACKETS = set("{[(")
+BRACKETS = {"}": "{", "]": "[", ")": "("}
+
+
+def FindEnclosingBracketGroup(input_str):
+    stack = []
+    start = -1
+    for index, char in enumerate(input_str):
+        if char in LBRACKETS:
+            stack.append(char)
+            if start == -1:
+                start = index
+        elif char in BRACKETS:
+            if not stack:
+                return (-1, -1)
+            if stack.pop() != BRACKETS[char]:
+                return (-1, -1)
+            if not stack:
+                return (start, index + 1)
+    return (-1, -1)
+
+
+def IsStrCanonicalInt(string):
+    """Returns True if |string| is in its canonical integer form.
+
+  The canonical form is such that str(int(string)) == string.
+  """
+    if type(string) is str:
+        # This function is called a lot so for maximum performance, avoid
+        # involving regexps which would otherwise make the code much
+        # shorter. Regexps would need twice the time of this function.
+        if string:
+            if string == "0":
+                return True
+            if string[0] == "-":
+                string = string[1:]
+                if not string:
+                    return False
+            if "1" <= string[0] <= "9":
+                return string.isdigit()
+
+    return False
+
+
+# This matches things like "<(asdf)", "<!(cmd)", "<!@(cmd)", "<|(list)",
+# "<!interpreter(arguments)", "<([list])", and even "<([)" and "<(<())".
+# In the last case, the inner "<()" is captured in match['content'].
+early_variable_re = re.compile(
+    r"(?P<replace>(?P<type><(?:(?:!?@?)|\|)?)"
+    r"(?P<command_string>[-a-zA-Z0-9_.]+)?"
+    r"$(?P<is_array>\s*\[?)"
+    r"(?P<content>.*?)(\]?)$)"
+)
+
+# This matches the same as early_variable_re, but with '>' instead of '<'.
+late_variable_re = re.compile(
+    r"(?P<replace>(?P<type>>(?:(?:!?@?)|\|)?)"
+    r"(?P<command_string>[-a-zA-Z0-9_.]+)?"
+    r"$(?P<is_array>\s*\[?)"
+    r"(?P<content>.*?)(\]?)$)"
+)
+
+# This matches the same as early_variable_re, but with '^' instead of '<'.
+latelate_variable_re = re.compile(
+    r"(?P<replace>(?P<type>[\^](?:(?:!?@?)|\|)?)"
+    r"(?P<command_string>[-a-zA-Z0-9_.]+)?"
+    r"$(?P<is_array>\s*\[?)"
+    r"(?P<content>.*?)(\]?)$)"
+)
+
+# Global cache of results from running commands so they don't have to be run
+# more then once.
+cached_command_results = {}
+
+
+def FixupPlatformCommand(cmd):
+    if sys.platform == "win32":
+        if type(cmd) is list:
+            cmd = [re.sub("^cat ", "type ", cmd[0])] + cmd[1:]
+        else:
+            cmd = re.sub("^cat ", "type ", cmd)
+    return cmd
+
+
+PHASE_EARLY = 0
+PHASE_LATE = 1
+PHASE_LATELATE = 2
+
+
+def ExpandVariables(input, phase, variables, build_file):
+    # Look for the pattern that gets expanded into variables
+    if phase == PHASE_EARLY:
+        variable_re = early_variable_re
+        expansion_symbol = "<"
+    elif phase == PHASE_LATE:
+        variable_re = late_variable_re
+        expansion_symbol = ">"
+    elif phase == PHASE_LATELATE:
+        variable_re = latelate_variable_re
+        expansion_symbol = "^"
+    else:
+        assert False
+
+    input_str = str(input)
+    if IsStrCanonicalInt(input_str):
+        return int(input_str)
+
+    # Do a quick scan to determine if an expensive regex search is warranted.
+    if expansion_symbol not in input_str:
+        return input_str
+
+    # Get the entire list of matches as a list of MatchObject instances.
+    # (using findall here would return strings instead of MatchObjects).
+    matches = list(variable_re.finditer(input_str))
+    if not matches:
+        return input_str
+
+    output = input_str
+    # Reverse the list of matches so that replacements are done right-to-left.
+    # That ensures that earlier replacements won't mess up the string in a
+    # way that causes later calls to find the earlier substituted text instead
+    # of what's intended for replacement.
+    matches.reverse()
+    for match_group in matches:
+        match = match_group.groupdict()
+        gyp.DebugOutput(gyp.DEBUG_VARIABLES, "Matches: %r", match)
+        # match['replace'] is the substring to look for, match['type']
+        # is the character code for the replacement type (< > <! >! <| >| <@
+        # >@ <!@ >!@), match['is_array'] contains a '[' for command
+        # arrays, and match['content'] is the name of the variable (< >)
+        # or command to run (<! >!). match['command_string'] is an optional
+        # command string. Currently, only 'pymod_do_main' is supported.
+
+        # run_command is true if a ! variant is used.
+        run_command = "!" in match["type"]
+        command_string = match["command_string"]
+
+        # file_list is true if a | variant is used.
+        file_list = "|" in match["type"]
+
+        # Capture these now so we can adjust them later.
+        replace_start = match_group.start("replace")
+        replace_end = match_group.end("replace")
+
+        # Find the ending paren, and re-evaluate the contained string.
+        (c_start, c_end) = FindEnclosingBracketGroup(input_str[replace_start:])
+
+        # Adjust the replacement range to match the entire command
+        # found by FindEnclosingBracketGroup (since the variable_re
+        # probably doesn't match the entire command if it contained
+        # nested variables).
+        replace_end = replace_start + c_end
+
+        # Find the "real" replacement, matching the appropriate closing
+        # paren, and adjust the replacement start and end.
+        replacement = input_str[replace_start:replace_end]
+
+        # Figure out what the contents of the variable parens are.
+        contents_start = replace_start + c_start + 1
+        contents_end = replace_end - 1
+        contents = input_str[contents_start:contents_end]
+
+        # Do filter substitution now for <|().
+        # Admittedly, this is different than the evaluation order in other
+        # contexts. However, since filtration has no chance to run on <|(),
+        # this seems like the only obvious way to give them access to filters.
+        if file_list:
+            processed_variables = gyp.simple_copy.deepcopy(variables)
+            ProcessListFiltersInDict(contents, processed_variables)
+            # Recurse to expand variables in the contents
+            contents = ExpandVariables(contents, phase, processed_variables, build_file)
+        else:
+            # Recurse to expand variables in the contents
+            contents = ExpandVariables(contents, phase, variables, build_file)
+
+        # Strip off leading/trailing whitespace so that variable matches are
+        # simpler below (and because they are rarely needed).
+        contents = contents.strip()
+
+        # expand_to_list is true if an @ variant is used.  In that case,
+        # the expansion should result in a list.  Note that the caller
+        # is to be expecting a list in return, and not all callers do
+        # because not all are working in list context.  Also, for list
+        # expansions, there can be no other text besides the variable
+        # expansion in the input string.
+        expand_to_list = "@" in match["type"] and input_str == replacement
+
+        if run_command or file_list:
+            # Find the build file's directory, so commands can be run or file lists
+            # generated relative to it.
+            build_file_dir = os.path.dirname(build_file)
+            if build_file_dir == "" and not file_list:
+                # If build_file is just a leaf filename indicating a file in the
+                # current directory, build_file_dir might be an empty string.  Set
+                # it to None to signal to subprocess.Popen that it should run the
+                # command in the current directory.
+                build_file_dir = None
+
+        # Support <|(listfile.txt ...) which generates a file
+        # containing items from a gyp list, generated at gyp time.
+        # This works around actions/rules which have more inputs than will
+        # fit on the command line.
+        if file_list:
+            if type(contents) is list:
+                contents_list = contents
+            else:
+                contents_list = contents.split(" ")
+            replacement = contents_list[0]
+            if os.path.isabs(replacement):
+                raise GypError('| cannot handle absolute paths, got "%s"' % replacement)
+
+            if not generator_filelist_paths:
+                path = os.path.join(build_file_dir, replacement)
+            else:
+                if os.path.isabs(build_file_dir):
+                    toplevel = generator_filelist_paths["toplevel"]
+                    rel_build_file_dir = gyp.common.RelativePath(
+                        build_file_dir, toplevel
+                    )
+                else:
+                    rel_build_file_dir = build_file_dir
+                qualified_out_dir = generator_filelist_paths["qualified_out_dir"]
+                path = os.path.join(qualified_out_dir, rel_build_file_dir, replacement)
+                gyp.common.EnsureDirExists(path)
+
+            replacement = gyp.common.RelativePath(path, build_file_dir)
+            f = gyp.common.WriteOnDiff(path)
+            for i in contents_list[1:]:
+                f.write("%s\n" % i)
+            f.close()
+
+        elif run_command:
+            use_shell = True
+            if match["is_array"]:
+                contents = eval(contents)
+                use_shell = False
+
+            # Check for a cached value to avoid executing commands, or generating
+            # file lists more than once. The cache key contains the command to be
+            # run as well as the directory to run it from, to account for commands
+            # that depend on their current directory.
+            # TODO(http://code.google.com/p/gyp/issues/detail?id=111): In theory,
+            # someone could author a set of GYP files where each time the command
+            # is invoked it produces different output by design. When the need
+            # arises, the syntax should be extended to support no caching off a
+            # command's output so it is run every time.
+            cache_key = (str(contents), build_file_dir)
+            cached_value = cached_command_results.get(cache_key, None)
+            if cached_value is None:
+                gyp.DebugOutput(
+                    gyp.DEBUG_VARIABLES,
+                    "Executing command '%s' in directory '%s'",
+                    contents,
+                    build_file_dir,
+                )
+
+                replacement = ""
+
+                if command_string == "pymod_do_main":
+                    # <!pymod_do_main(modulename param eters) loads |modulename| as a
+                    # python module and then calls that module's DoMain() function,
+                    # passing ["param", "eters"] as a single list argument. For modules
+                    # that don't load quickly, this can be faster than
+                    # <!(python modulename param eters). Do this in |build_file_dir|.
+                    oldwd = os.getcwd()  # Python doesn't like os.open('.'): no fchdir.
+                    if build_file_dir:  # build_file_dir may be None (see above).
+                        os.chdir(build_file_dir)
+                    sys.path.append(os.getcwd())
+                    try:
+
+                        parsed_contents = shlex.split(contents)
+                        try:
+                            py_module = __import__(parsed_contents[0])
+                        except ImportError as e:
+                            raise GypError(
+                                "Error importing pymod_do_main"
+                                "module (%s): %s" % (parsed_contents[0], e)
+                            )
+                        replacement = str(
+                            py_module.DoMain(parsed_contents[1:])
+                        ).rstrip()
+                    finally:
+                        sys.path.pop()
+                        os.chdir(oldwd)
+                    assert replacement is not None
+                elif command_string:
+                    raise GypError(
+                        "Unknown command string '%s' in '%s'."
+                        % (command_string, contents)
+                    )
+                else:
+                    # Fix up command with platform specific workarounds.
+                    contents = FixupPlatformCommand(contents)
+                    try:
+                        p = subprocess.Popen(
+                            contents,
+                            shell=use_shell,
+                            stdout=subprocess.PIPE,
+                            stderr=subprocess.PIPE,
+                            stdin=subprocess.PIPE,
+                            cwd=build_file_dir,
+                        )
+                    except Exception as e:
+                        raise GypError(
+                            "%s while executing command '%s' in %s"
+                            % (e, contents, build_file)
+                        )
+
+                    p_stdout, p_stderr = p.communicate("")
+                    p_stdout = p_stdout.decode("utf-8")
+                    p_stderr = p_stderr.decode("utf-8")
+
+                    if p.wait() != 0 or p_stderr:
+                        sys.stderr.write(p_stderr)
+                        # Simulate check_call behavior, since check_call only exists
+                        # in python 2.5 and later.
+                        raise GypError(
+                            "Call to '%s' returned exit status %d while in %s."
+                            % (contents, p.returncode, build_file)
+                        )
+                    replacement = p_stdout.rstrip()
+
+                cached_command_results[cache_key] = replacement
+            else:
+                gyp.DebugOutput(
+                    gyp.DEBUG_VARIABLES,
+                    "Had cache value for command '%s' in directory '%s'",
+                    contents,
+                    build_file_dir,
+                )
+                replacement = cached_value
+
+        else:
+            if contents not in variables:
+                if contents[-1] in ["!", "/"]:
+                    # In order to allow cross-compiles (nacl) to happen more naturally,
+                    # we will allow references to >(sources/) etc. to resolve to
+                    # and empty list if undefined. This allows actions to:
+                    # 'action!': [
+                    #   '>@(_sources!)',
+                    # ],
+                    # 'action/': [
+                    #   '>@(_sources/)',
+                    # ],
+                    replacement = []
+                else:
+                    raise GypError(
+                        "Undefined variable " + contents + " in " + build_file
+                    )
+            else:
+                replacement = variables[contents]
+
+        if isinstance(replacement, bytes) and not isinstance(replacement, str):
+            replacement = replacement.decode("utf-8")  # done on Python 3 only
+        if type(replacement) is list:
+            for item in replacement:
+                if isinstance(item, bytes) and not isinstance(item, str):
+                    item = item.decode("utf-8")  # done on Python 3 only
+                if not contents[-1] == "/" and type(item) not in (str, int):
+                    raise GypError(
+                        "Variable "
+                        + contents
+                        + " must expand to a string or list of strings; "
+                        + "list contains a "
+                        + item.__class__.__name__
+                    )
+            # Run through the list and handle variable expansions in it.  Since
+            # the list is guaranteed not to contain dicts, this won't do anything
+            # with conditions sections.
+            ProcessVariablesAndConditionsInList(
+                replacement, phase, variables, build_file
+            )
+        elif type(replacement) not in (str, int):
+            raise GypError(
+                "Variable "
+                + contents
+                + " must expand to a string or list of strings; "
+                + "found a "
+                + replacement.__class__.__name__
+            )
+
+        if expand_to_list:
+            # Expanding in list context.  It's guaranteed that there's only one
+            # replacement to do in |input_str| and that it's this replacement.  See
+            # above.
+            if type(replacement) is list:
+                # If it's already a list, make a copy.
+                output = replacement[:]
+            else:
+                # Split it the same way sh would split arguments.
+                output = shlex.split(str(replacement))
+        else:
+            # Expanding in string context.
+            encoded_replacement = ""
+            if type(replacement) is list:
+                # When expanding a list into string context, turn the list items
+                # into a string in a way that will work with a subprocess call.
+                #
+                # TODO(mark): This isn't completely correct.  This should
+                # call a generator-provided function that observes the
+                # proper list-to-argument quoting rules on a specific
+                # platform instead of just calling the POSIX encoding
+                # routine.
+                encoded_replacement = gyp.common.EncodePOSIXShellList(replacement)
+            else:
+                encoded_replacement = replacement
+
+            output = (
+                output[:replace_start] + str(encoded_replacement) + output[replace_end:]
+            )
+        # Prepare for the next match iteration.
+        input_str = output
+
+    if output == input:
+        gyp.DebugOutput(
+            gyp.DEBUG_VARIABLES,
+            "Found only identity matches on %r, avoiding infinite " "recursion.",
+            output,
+        )
+    else:
+        # Look for more matches now that we've replaced some, to deal with
+        # expanding local variables (variables defined in the same
+        # variables block as this one).
+        gyp.DebugOutput(gyp.DEBUG_VARIABLES, "Found output %r, recursing.", output)
+        if type(output) is list:
+            if output and type(output[0]) is list:
+                # Leave output alone if it's a list of lists.
+                # We don't want such lists to be stringified.
+                pass
+            else:
+                new_output = []
+                for item in output:
+                    new_output.append(
+                        ExpandVariables(item, phase, variables, build_file)
+                    )
+                output = new_output
+        else:
+            output = ExpandVariables(output, phase, variables, build_file)
+
+    # Convert all strings that are canonically-represented integers into integers.
+    if type(output) is list:
+        for index, outstr in enumerate(output):
+            if IsStrCanonicalInt(outstr):
+                output[index] = int(outstr)
+    elif IsStrCanonicalInt(output):
+        output = int(output)
+
+    return output
+
+
+# The same condition is often evaluated over and over again so it
+# makes sense to cache as much as possible between evaluations.
+cached_conditions_asts = {}
+
+
+def EvalCondition(condition, conditions_key, phase, variables, build_file):
+    """Returns the dict that should be used or None if the result was
+  that nothing should be used."""
+    if type(condition) is not list:
+        raise GypError(conditions_key + " must be a list")
+    if len(condition) < 2:
+        # It's possible that condition[0] won't work in which case this
+        # attempt will raise its own IndexError.  That's probably fine.
+        raise GypError(
+            conditions_key
+            + " "
+            + condition[0]
+            + " must be at least length 2, not "
+            + str(len(condition))
+        )
+
+    i = 0
+    result = None
+    while i < len(condition):
+        cond_expr = condition[i]
+        true_dict = condition[i + 1]
+        if type(true_dict) is not dict:
+            raise GypError(
+                "{} {} must be followed by a dictionary, not {}".format(
+                    conditions_key, cond_expr, type(true_dict)
+                )
+            )
+        if len(condition) > i + 2 and type(condition[i + 2]) is dict:
+            false_dict = condition[i + 2]
+            i = i + 3
+            if i != len(condition):
+                raise GypError(
+                    "{} {} has {} unexpected trailing items".format(
+                        conditions_key, cond_expr, len(condition) - i
+                    )
+                )
+        else:
+            false_dict = None
+            i = i + 2
+        if result is None:
+            result = EvalSingleCondition(
+                cond_expr, true_dict, false_dict, phase, variables, build_file
+            )
+
+    return result
+
+
+def EvalSingleCondition(cond_expr, true_dict, false_dict, phase, variables, build_file):
+    """Returns true_dict if cond_expr evaluates to true, and false_dict
+  otherwise."""
+    # Do expansions on the condition itself.  Since the condition can naturally
+    # contain variable references without needing to resort to GYP expansion
+    # syntax, this is of dubious value for variables, but someone might want to
+    # use a command expansion directly inside a condition.
+    cond_expr_expanded = ExpandVariables(cond_expr, phase, variables, build_file)
+    if type(cond_expr_expanded) not in (str, int):
+        raise ValueError(
+            "Variable expansion in this context permits str and int "
+            + "only, found "
+            + cond_expr_expanded.__class__.__name__
+        )
+
+    try:
+        if cond_expr_expanded in cached_conditions_asts:
+            ast_code = cached_conditions_asts[cond_expr_expanded]
+        else:
+            ast_code = compile(cond_expr_expanded, "<string>", "eval")
+            cached_conditions_asts[cond_expr_expanded] = ast_code
+        env = {"__builtins__": {}, "v": StrictVersion}
+        if eval(ast_code, env, variables):
+            return true_dict
+        return false_dict
+    except SyntaxError as e:
+        syntax_error = SyntaxError(
+            "%s while evaluating condition '%s' in %s "
+            "at character %d." % (str(e.args[0]), e.text, build_file, e.offset),
+            e.filename,
+            e.lineno,
+            e.offset,
+            e.text,
+        )
+        raise syntax_error
+    except NameError as e:
+        gyp.common.ExceptionAppend(
+            e,
+            f"while evaluating condition '{cond_expr_expanded}' in {build_file}",
+        )
+        raise GypError(e)
+
+
+def ProcessConditionsInDict(the_dict, phase, variables, build_file):
+    # Process a 'conditions' or 'target_conditions' section in the_dict,
+    # depending on phase.
+    # early -> conditions
+    # late -> target_conditions
+    # latelate -> no conditions
+    #
+    # Each item in a conditions list consists of cond_expr, a string expression
+    # evaluated as the condition, and true_dict, a dict that will be merged into
+    # the_dict if cond_expr evaluates to true.  Optionally, a third item,
+    # false_dict, may be present.  false_dict is merged into the_dict if
+    # cond_expr evaluates to false.
+    #
+    # Any dict merged into the_dict will be recursively processed for nested
+    # conditionals and other expansions, also according to phase, immediately
+    # prior to being merged.
+
+    if phase == PHASE_EARLY:
+        conditions_key = "conditions"
+    elif phase == PHASE_LATE:
+        conditions_key = "target_conditions"
+    elif phase == PHASE_LATELATE:
+        return
+    else:
+        assert False
+
+    if conditions_key not in the_dict:
+        return
+
+    conditions_list = the_dict[conditions_key]
+    # Unhook the conditions list, it's no longer needed.
+    del the_dict[conditions_key]
+
+    for condition in conditions_list:
+        merge_dict = EvalCondition(
+            condition, conditions_key, phase, variables, build_file
+        )
+
+        if merge_dict is not None:
+            # Expand variables and nested conditinals in the merge_dict before
+            # merging it.
+            ProcessVariablesAndConditionsInDict(
+                merge_dict, phase, variables, build_file
+            )
+
+            MergeDicts(the_dict, merge_dict, build_file, build_file)
+
+
+def LoadAutomaticVariablesFromDict(variables, the_dict):
+    # Any keys with plain string values in the_dict become automatic variables.
+    # The variable name is the key name with a "_" character prepended.
+    for key, value in the_dict.items():
+        if type(value) in (str, int, list):
+            variables["_" + key] = value
+
+
+def LoadVariablesFromVariablesDict(variables, the_dict, the_dict_key):
+    # Any keys in the_dict's "variables" dict, if it has one, becomes a
+    # variable.  The variable name is the key name in the "variables" dict.
+    # Variables that end with the % character are set only if they are unset in
+    # the variables dict.  the_dict_key is the name of the key that accesses
+    # the_dict in the_dict's parent dict.  If the_dict's parent is not a dict
+    # (it could be a list or it could be parentless because it is a root dict),
+    # the_dict_key will be None.
+    for key, value in the_dict.get("variables", {}).items():
+        if type(value) not in (str, int, list):
+            continue
+
+        if key.endswith("%"):
+            variable_name = key[:-1]
+            if variable_name in variables:
+                # If the variable is already set, don't set it.
+                continue
+            if the_dict_key == "variables" and variable_name in the_dict:
+                # If the variable is set without a % in the_dict, and the_dict is a
+                # variables dict (making |variables| a variables sub-dict of a
+                # variables dict), use the_dict's definition.
+                value = the_dict[variable_name]
+        else:
+            variable_name = key
+
+        variables[variable_name] = value
+
+
+def ProcessVariablesAndConditionsInDict(
+    the_dict, phase, variables_in, build_file, the_dict_key=None
+):
+    """Handle all variable and command expansion and conditional evaluation.
+
+  This function is the public entry point for all variable expansions and
+  conditional evaluations.  The variables_in dictionary will not be modified
+  by this function.
+  """
+
+    # Make a copy of the variables_in dict that can be modified during the
+    # loading of automatics and the loading of the variables dict.
+    variables = variables_in.copy()
+    LoadAutomaticVariablesFromDict(variables, the_dict)
+
+    if "variables" in the_dict:
+        # Make sure all the local variables are added to the variables
+        # list before we process them so that you can reference one
+        # variable from another.  They will be fully expanded by recursion
+        # in ExpandVariables.
+        for key, value in the_dict["variables"].items():
+            variables[key] = value
+
+        # Handle the associated variables dict first, so that any variable
+        # references within can be resolved prior to using them as variables.
+        # Pass a copy of the variables dict to avoid having it be tainted.
+        # Otherwise, it would have extra automatics added for everything that
+        # should just be an ordinary variable in this scope.
+        ProcessVariablesAndConditionsInDict(
+            the_dict["variables"], phase, variables, build_file, "variables"
+        )
+
+    LoadVariablesFromVariablesDict(variables, the_dict, the_dict_key)
+
+    for key, value in the_dict.items():
+        # Skip "variables", which was already processed if present.
+        if key != "variables" and type(value) is str:
+            expanded = ExpandVariables(value, phase, variables, build_file)
+            if type(expanded) not in (str, int):
+                raise ValueError(
+                    "Variable expansion in this context permits str and int "
+                    + "only, found "
+                    + expanded.__class__.__name__
+                    + " for "
+                    + key
+                )
+            the_dict[key] = expanded
+
+    # Variable expansion may have resulted in changes to automatics.  Reload.
+    # TODO(mark): Optimization: only reload if no changes were made.
+    variables = variables_in.copy()
+    LoadAutomaticVariablesFromDict(variables, the_dict)
+    LoadVariablesFromVariablesDict(variables, the_dict, the_dict_key)
+
+    # Process conditions in this dict.  This is done after variable expansion
+    # so that conditions may take advantage of expanded variables.  For example,
+    # if the_dict contains:
+    #   {'type':       '<(library_type)',
+    #    'conditions': [['_type=="static_library"', { ... }]]},
+    # _type, as used in the condition, will only be set to the value of
+    # library_type if variable expansion is performed before condition
+    # processing.  However, condition processing should occur prior to recursion
+    # so that variables (both automatic and "variables" dict type) may be
+    # adjusted by conditions sections, merged into the_dict, and have the
+    # intended impact on contained dicts.
+    #
+    # This arrangement means that a "conditions" section containing a "variables"
+    # section will only have those variables effective in subdicts, not in
+    # the_dict.  The workaround is to put a "conditions" section within a
+    # "variables" section.  For example:
+    #   {'conditions': [['os=="mac"', {'variables': {'define': 'IS_MAC'}}]],
+    #    'defines':    ['<(define)'],
+    #    'my_subdict': {'defines': ['<(define)']}},
+    # will not result in "IS_MAC" being appended to the "defines" list in the
+    # current scope but would result in it being appended to the "defines" list
+    # within "my_subdict".  By comparison:
+    #   {'variables': {'conditions': [['os=="mac"', {'define': 'IS_MAC'}]]},
+    #    'defines':    ['<(define)'],
+    #    'my_subdict': {'defines': ['<(define)']}},
+    # will append "IS_MAC" to both "defines" lists.
+
+    # Evaluate conditions sections, allowing variable expansions within them
+    # as well as nested conditionals.  This will process a 'conditions' or
+    # 'target_conditions' section, perform appropriate merging and recursive
+    # conditional and variable processing, and then remove the conditions section
+    # from the_dict if it is present.
+    ProcessConditionsInDict(the_dict, phase, variables, build_file)
+
+    # Conditional processing may have resulted in changes to automatics or the
+    # variables dict.  Reload.
+    variables = variables_in.copy()
+    LoadAutomaticVariablesFromDict(variables, the_dict)
+    LoadVariablesFromVariablesDict(variables, the_dict, the_dict_key)
+
+    # Recurse into child dicts, or process child lists which may result in
+    # further recursion into descendant dicts.
+    for key, value in the_dict.items():
+        # Skip "variables" and string values, which were already processed if
+        # present.
+        if key == "variables" or type(value) is str:
+            continue
+        if type(value) is dict:
+            # Pass a copy of the variables dict so that subdicts can't influence
+            # parents.
+            ProcessVariablesAndConditionsInDict(
+                value, phase, variables, build_file, key
+            )
+        elif type(value) is list:
+            # The list itself can't influence the variables dict, and
+            # ProcessVariablesAndConditionsInList will make copies of the variables
+            # dict if it needs to pass it to something that can influence it.  No
+            # copy is necessary here.
+            ProcessVariablesAndConditionsInList(value, phase, variables, build_file)
+        elif type(value) is not int:
+            raise TypeError("Unknown type " + value.__class__.__name__ + " for " + key)
+
+
+def ProcessVariablesAndConditionsInList(the_list, phase, variables, build_file):
+    # Iterate using an index so that new values can be assigned into the_list.
+    index = 0
+    while index < len(the_list):
+        item = the_list[index]
+        if type(item) is dict:
+            # Make a copy of the variables dict so that it won't influence anything
+            # outside of its own scope.
+            ProcessVariablesAndConditionsInDict(item, phase, variables, build_file)
+        elif type(item) is list:
+            ProcessVariablesAndConditionsInList(item, phase, variables, build_file)
+        elif type(item) is str:
+            expanded = ExpandVariables(item, phase, variables, build_file)
+            if type(expanded) in (str, int):
+                the_list[index] = expanded
+            elif type(expanded) is list:
+                the_list[index : index + 1] = expanded
+                index += len(expanded)
+
+                # index now identifies the next item to examine.  Continue right now
+                # without falling into the index increment below.
+                continue
+            else:
+                raise ValueError(
+                    "Variable expansion in this context permits strings and "
+                    + "lists only, found "
+                    + expanded.__class__.__name__
+                    + " at "
+                    + index
+                )
+        elif type(item) is not int:
+            raise TypeError(
+                "Unknown type " + item.__class__.__name__ + " at index " + index
+            )
+        index = index + 1
+
+
+def BuildTargetsDict(data):
+    """Builds a dict mapping fully-qualified target names to their target dicts.
+
+  |data| is a dict mapping loaded build files by pathname relative to the
+  current directory.  Values in |data| are build file contents.  For each
+  |data| value with a "targets" key, the value of the "targets" key is taken
+  as a list containing target dicts.  Each target's fully-qualified name is
+  constructed from the pathname of the build file (|data| key) and its
+  "target_name" property.  These fully-qualified names are used as the keys
+  in the returned dict.  These keys provide access to the target dicts,
+  the dicts in the "targets" lists.
+  """
+
+    targets = {}
+    for build_file in data["target_build_files"]:
+        for target in data[build_file].get("targets", []):
+            target_name = gyp.common.QualifiedTarget(
+                build_file, target["target_name"], target["toolset"]
+            )
+            if target_name in targets:
+                raise GypError("Duplicate target definitions for " + target_name)
+            targets[target_name] = target
+
+    return targets
+
+
+def QualifyDependencies(targets):
+    """Make dependency links fully-qualified relative to the current directory.
+
+  |targets| is a dict mapping fully-qualified target names to their target
+  dicts.  For each target in this dict, keys known to contain dependency
+  links are examined, and any dependencies referenced will be rewritten
+  so that they are fully-qualified and relative to the current directory.
+  All rewritten dependencies are suitable for use as keys to |targets| or a
+  similar dict.
+  """
+
+    all_dependency_sections = [
+        dep + op for dep in dependency_sections for op in ("", "!", "/")
+    ]
+
+    for target, target_dict in targets.items():
+        target_build_file = gyp.common.BuildFile(target)
+        toolset = target_dict["toolset"]
+        for dependency_key in all_dependency_sections:
+            dependencies = target_dict.get(dependency_key, [])
+            for index, dep in enumerate(dependencies):
+                dep_file, dep_target, dep_toolset = gyp.common.ResolveTarget(
+                    target_build_file, dep, toolset
+                )
+                if not multiple_toolsets:
+                    # Ignore toolset specification in the dependency if it is specified.
+                    dep_toolset = toolset
+                dependency = gyp.common.QualifiedTarget(
+                    dep_file, dep_target, dep_toolset
+                )
+                dependencies[index] = dependency
+
+                # Make sure anything appearing in a list other than "dependencies" also
+                # appears in the "dependencies" list.
+                if (
+                    dependency_key != "dependencies"
+                    and dependency not in target_dict["dependencies"]
+                ):
+                    raise GypError(
+                        "Found "
+                        + dependency
+                        + " in "
+                        + dependency_key
+                        + " of "
+                        + target
+                        + ", but not in dependencies"
+                    )
+
+
+def ExpandWildcardDependencies(targets, data):
+    """Expands dependencies specified as build_file:*.
+
+  For each target in |targets|, examines sections containing links to other
+  targets.  If any such section contains a link of the form build_file:*, it
+  is taken as a wildcard link, and is expanded to list each target in
+  build_file.  The |data| dict provides access to build file dicts.
+
+  Any target that does not wish to be included by wildcard can provide an
+  optional "suppress_wildcard" key in its target dict.  When present and
+  true, a wildcard dependency link will not include such targets.
+
+  All dependency names, including the keys to |targets| and the values in each
+  dependency list, must be qualified when this function is called.
+  """
+
+    for target, target_dict in targets.items():
+        target_build_file = gyp.common.BuildFile(target)
+        for dependency_key in dependency_sections:
+            dependencies = target_dict.get(dependency_key, [])
+
+            # Loop this way instead of "for dependency in" or "for index in range"
+            # because the dependencies list will be modified within the loop body.
+            index = 0
+            while index < len(dependencies):
+                (
+                    dependency_build_file,
+                    dependency_target,
+                    dependency_toolset,
+                ) = gyp.common.ParseQualifiedTarget(dependencies[index])
+                if dependency_target != "*" and dependency_toolset != "*":
+                    # Not a wildcard.  Keep it moving.
+                    index = index + 1
+                    continue
+
+                if dependency_build_file == target_build_file:
+                    # It's an error for a target to depend on all other targets in
+                    # the same file, because a target cannot depend on itself.
+                    raise GypError(
+                        "Found wildcard in "
+                        + dependency_key
+                        + " of "
+                        + target
+                        + " referring to same build file"
+                    )
+
+                # Take the wildcard out and adjust the index so that the next
+                # dependency in the list will be processed the next time through the
+                # loop.
+                del dependencies[index]
+                index = index - 1
+
+                # Loop through the targets in the other build file, adding them to
+                # this target's list of dependencies in place of the removed
+                # wildcard.
+                dependency_target_dicts = data[dependency_build_file]["targets"]
+                for dependency_target_dict in dependency_target_dicts:
+                    if int(dependency_target_dict.get("suppress_wildcard", False)):
+                        continue
+                    dependency_target_name = dependency_target_dict["target_name"]
+                    if (
+                        dependency_target != "*"
+                        and dependency_target != dependency_target_name
+                    ):
+                        continue
+                    dependency_target_toolset = dependency_target_dict["toolset"]
+                    if (
+                        dependency_toolset != "*"
+                        and dependency_toolset != dependency_target_toolset
+                    ):
+                        continue
+                    dependency = gyp.common.QualifiedTarget(
+                        dependency_build_file,
+                        dependency_target_name,
+                        dependency_target_toolset,
+                    )
+                    index = index + 1
+                    dependencies.insert(index, dependency)
+
+                index = index + 1
+
+
+def Unify(items):
+    """Removes duplicate elements from items, keeping the first element."""
+    seen = {}
+    return [seen.setdefault(e, e) for e in items if e not in seen]
+
+
+def RemoveDuplicateDependencies(targets):
+    """Makes sure every dependency appears only once in all targets's dependency
+  lists."""
+    for target_name, target_dict in targets.items():
+        for dependency_key in dependency_sections:
+            dependencies = target_dict.get(dependency_key, [])
+            if dependencies:
+                target_dict[dependency_key] = Unify(dependencies)
+
+
+def Filter(items, item):
+    """Removes item from items."""
+    res = {}
+    return [res.setdefault(e, e) for e in items if e != item]
+
+
+def RemoveSelfDependencies(targets):
+    """Remove self dependencies from targets that have the prune_self_dependency
+  variable set."""
+    for target_name, target_dict in targets.items():
+        for dependency_key in dependency_sections:
+            dependencies = target_dict.get(dependency_key, [])
+            if dependencies:
+                for t in dependencies:
+                    if t == target_name:
+                        if (
+                            targets[t]
+                            .get("variables", {})
+                            .get("prune_self_dependency", 0)
+                        ):
+                            target_dict[dependency_key] = Filter(
+                                dependencies, target_name
+                            )
+
+
+def RemoveLinkDependenciesFromNoneTargets(targets):
+    """Remove dependencies having the 'link_dependency' attribute from the 'none'
+  targets."""
+    for target_name, target_dict in targets.items():
+        for dependency_key in dependency_sections:
+            dependencies = target_dict.get(dependency_key, [])
+            if dependencies:
+                for t in dependencies:
+                    if target_dict.get("type", None) == "none":
+                        if targets[t].get("variables", {}).get("link_dependency", 0):
+                            target_dict[dependency_key] = Filter(
+                                target_dict[dependency_key], t
+                            )
+
+
+class DependencyGraphNode:
+    """
+
+  Attributes:
+    ref: A reference to an object that this DependencyGraphNode represents.
+    dependencies: List of DependencyGraphNodes on which this one depends.
+    dependents: List of DependencyGraphNodes that depend on this one.
+  """
+
+    class CircularException(GypError):
+        pass
+
+    def __init__(self, ref):
+        self.ref = ref
+        self.dependencies = []
+        self.dependents = []
+
+    def __repr__(self):
+        return "<DependencyGraphNode: %r>" % self.ref
+
+    def FlattenToList(self):
+        # flat_list is the sorted list of dependencies - actually, the list items
+        # are the "ref" attributes of DependencyGraphNodes.  Every target will
+        # appear in flat_list after all of its dependencies, and before all of its
+        # dependents.
+        flat_list = OrderedSet()
+
+        def ExtractNodeRef(node):
+            """Extracts the object that the node represents from the given node."""
+            return node.ref
+
+        # in_degree_zeros is the list of DependencyGraphNodes that have no
+        # dependencies not in flat_list.  Initially, it is a copy of the children
+        # of this node, because when the graph was built, nodes with no
+        # dependencies were made implicit dependents of the root node.
+        in_degree_zeros = sorted(self.dependents[:], key=ExtractNodeRef)
+
+        while in_degree_zeros:
+            # Nodes in in_degree_zeros have no dependencies not in flat_list, so they
+            # can be appended to flat_list.  Take these nodes out of in_degree_zeros
+            # as work progresses, so that the next node to process from the list can
+            # always be accessed at a consistent position.
+            node = in_degree_zeros.pop()
+            flat_list.add(node.ref)
+
+            # Look at dependents of the node just added to flat_list.  Some of them
+            # may now belong in in_degree_zeros.
+            for node_dependent in sorted(node.dependents, key=ExtractNodeRef):
+                is_in_degree_zero = True
+                # TODO: We want to check through the
+                # node_dependent.dependencies list but if it's long and we
+                # always start at the beginning, then we get O(n^2) behaviour.
+                for node_dependent_dependency in sorted(
+                    node_dependent.dependencies, key=ExtractNodeRef
+                ):
+                    if node_dependent_dependency.ref not in flat_list:
+                        # The dependent one or more dependencies not in flat_list.
+                        # There will be more chances to add it to flat_list
+                        # when examining it again as a dependent of those other
+                        # dependencies, provided that there are no cycles.
+                        is_in_degree_zero = False
+                        break
+
+                if is_in_degree_zero:
+                    # All of the dependent's dependencies are already in flat_list.  Add
+                    # it to in_degree_zeros where it will be processed in a future
+                    # iteration of the outer loop.
+                    in_degree_zeros += [node_dependent]
+
+        return list(flat_list)
+
+    def FindCycles(self):
+        """
+    Returns a list of cycles in the graph, where each cycle is its own list.
+    """
+        results = []
+        visited = set()
+
+        def Visit(node, path):
+            for child in node.dependents:
+                if child in path:
+                    results.append([child] + path[: path.index(child) + 1])
+                elif child not in visited:
+                    visited.add(child)
+                    Visit(child, [child] + path)
+
+        visited.add(self)
+        Visit(self, [self])
+
+        return results
+
+    def DirectDependencies(self, dependencies=None):
+        """Returns a list of just direct dependencies."""
+        if dependencies is None:
+            dependencies = []
+
+        for dependency in self.dependencies:
+            # Check for None, corresponding to the root node.
+            if dependency.ref and dependency.ref not in dependencies:
+                dependencies.append(dependency.ref)
+
+        return dependencies
+
+    def _AddImportedDependencies(self, targets, dependencies=None):
+        """Given a list of direct dependencies, adds indirect dependencies that
+    other dependencies have declared to export their settings.
+
+    This method does not operate on self.  Rather, it operates on the list
+    of dependencies in the |dependencies| argument.  For each dependency in
+    that list, if any declares that it exports the settings of one of its
+    own dependencies, those dependencies whose settings are "passed through"
+    are added to the list.  As new items are added to the list, they too will
+    be processed, so it is possible to import settings through multiple levels
+    of dependencies.
+
+    This method is not terribly useful on its own, it depends on being
+    "primed" with a list of direct dependencies such as one provided by
+    DirectDependencies.  DirectAndImportedDependencies is intended to be the
+    public entry point.
+    """
+
+        if dependencies is None:
+            dependencies = []
+
+        index = 0
+        while index < len(dependencies):
+            dependency = dependencies[index]
+            dependency_dict = targets[dependency]
+            # Add any dependencies whose settings should be imported to the list
+            # if not already present.  Newly-added items will be checked for
+            # their own imports when the list iteration reaches them.
+            # Rather than simply appending new items, insert them after the
+            # dependency that exported them.  This is done to more closely match
+            # the depth-first method used by DeepDependencies.
+            add_index = 1
+            for imported_dependency in dependency_dict.get(
+                "export_dependent_settings", []
+            ):
+                if imported_dependency not in dependencies:
+                    dependencies.insert(index + add_index, imported_dependency)
+                    add_index = add_index + 1
+            index = index + 1
+
+        return dependencies
+
+    def DirectAndImportedDependencies(self, targets, dependencies=None):
+        """Returns a list of a target's direct dependencies and all indirect
+    dependencies that a dependency has advertised settings should be exported
+    through the dependency for.
+    """
+
+        dependencies = self.DirectDependencies(dependencies)
+        return self._AddImportedDependencies(targets, dependencies)
+
+    def DeepDependencies(self, dependencies=None):
+        """Returns an OrderedSet of all of a target's dependencies, recursively."""
+        if dependencies is None:
+            # Using a list to get ordered output and a set to do fast "is it
+            # already added" checks.
+            dependencies = OrderedSet()
+
+        for dependency in self.dependencies:
+            # Check for None, corresponding to the root node.
+            if dependency.ref is None:
+                continue
+            if dependency.ref not in dependencies:
+                dependency.DeepDependencies(dependencies)
+                dependencies.add(dependency.ref)
+
+        return dependencies
+
+    def _LinkDependenciesInternal(
+        self, targets, include_shared_libraries, dependencies=None, initial=True
+    ):
+        """Returns an OrderedSet of dependency targets that are linked
+    into this target.
+
+    This function has a split personality, depending on the setting of
+    |initial|.  Outside callers should always leave |initial| at its default
+    setting.
+
+    When adding a target to the list of dependencies, this function will
+    recurse into itself with |initial| set to False, to collect dependencies
+    that are linked into the linkable target for which the list is being built.
+
+    If |include_shared_libraries| is False, the resulting dependencies will not
+    include shared_library targets that are linked into this target.
+    """
+        if dependencies is None:
+            # Using a list to get ordered output and a set to do fast "is it
+            # already added" checks.
+            dependencies = OrderedSet()
+
+        # Check for None, corresponding to the root node.
+        if self.ref is None:
+            return dependencies
+
+        # It's kind of sucky that |targets| has to be passed into this function,
+        # but that's presently the easiest way to access the target dicts so that
+        # this function can find target types.
+
+        if "target_name" not in targets[self.ref]:
+            raise GypError("Missing 'target_name' field in target.")
+
+        if "type" not in targets[self.ref]:
+            raise GypError(
+                "Missing 'type' field in target %s" % targets[self.ref]["target_name"]
+            )
+
+        target_type = targets[self.ref]["type"]
+
+        is_linkable = target_type in linkable_types
+
+        if initial and not is_linkable:
+            # If this is the first target being examined and it's not linkable,
+            # return an empty list of link dependencies, because the link
+            # dependencies are intended to apply to the target itself (initial is
+            # True) and this target won't be linked.
+            return dependencies
+
+        # Don't traverse 'none' targets if explicitly excluded.
+        if target_type == "none" and not targets[self.ref].get(
+            "dependencies_traverse", True
+        ):
+            dependencies.add(self.ref)
+            return dependencies
+
+        # Executables, mac kernel extensions, windows drivers and loadable modules
+        # are already fully and finally linked. Nothing else can be a link
+        # dependency of them, there can only be dependencies in the sense that a
+        # dependent target might run an executable or load the loadable_module.
+        if not initial and target_type in (
+            "executable",
+            "loadable_module",
+            "mac_kernel_extension",
+            "windows_driver",
+        ):
+            return dependencies
+
+        # Shared libraries are already fully linked.  They should only be included
+        # in |dependencies| when adjusting static library dependencies (in order to
+        # link against the shared_library's import lib), but should not be included
+        # in |dependencies| when propagating link_settings.
+        # The |include_shared_libraries| flag controls which of these two cases we
+        # are handling.
+        if (
+            not initial
+            and target_type == "shared_library"
+            and not include_shared_libraries
+        ):
+            return dependencies
+
+        # The target is linkable, add it to the list of link dependencies.
+        if self.ref not in dependencies:
+            dependencies.add(self.ref)
+            if initial or not is_linkable:
+                # If this is a subsequent target and it's linkable, don't look any
+                # further for linkable dependencies, as they'll already be linked into
+                # this target linkable.  Always look at dependencies of the initial
+                # target, and always look at dependencies of non-linkables.
+                for dependency in self.dependencies:
+                    dependency._LinkDependenciesInternal(
+                        targets, include_shared_libraries, dependencies, False
+                    )
+
+        return dependencies
+
+    def DependenciesForLinkSettings(self, targets):
+        """
+    Returns a list of dependency targets whose link_settings should be merged
+    into this target.
+    """
+
+        # TODO(sbaig) Currently, chrome depends on the bug that shared libraries'
+        # link_settings are propagated.  So for now, we will allow it, unless the
+        # 'allow_sharedlib_linksettings_propagation' flag is explicitly set to
+        # False.  Once chrome is fixed, we can remove this flag.
+        include_shared_libraries = targets[self.ref].get(
+            "allow_sharedlib_linksettings_propagation", True
+        )
+        return self._LinkDependenciesInternal(targets, include_shared_libraries)
+
+    def DependenciesToLinkAgainst(self, targets):
+        """
+    Returns a list of dependency targets that are linked into this target.
+    """
+        return self._LinkDependenciesInternal(targets, True)
+
+
+def BuildDependencyList(targets):
+    # Create a DependencyGraphNode for each target.  Put it into a dict for easy
+    # access.
+    dependency_nodes = {}
+    for target, spec in targets.items():
+        if target not in dependency_nodes:
+            dependency_nodes[target] = DependencyGraphNode(target)
+
+    # Set up the dependency links.  Targets that have no dependencies are treated
+    # as dependent on root_node.
+    root_node = DependencyGraphNode(None)
+    for target, spec in targets.items():
+        target_node = dependency_nodes[target]
+        dependencies = spec.get("dependencies")
+        if not dependencies:
+            target_node.dependencies = [root_node]
+            root_node.dependents.append(target_node)
+        else:
+            for dependency in dependencies:
+                dependency_node = dependency_nodes.get(dependency)
+                if not dependency_node:
+                    raise GypError(
+                        "Dependency '%s' not found while "
+                        "trying to load target %s" % (dependency, target)
+                    )
+                target_node.dependencies.append(dependency_node)
+                dependency_node.dependents.append(target_node)
+
+    flat_list = root_node.FlattenToList()
+
+    # If there's anything left unvisited, there must be a circular dependency
+    # (cycle).
+    if len(flat_list) != len(targets):
+        if not root_node.dependents:
+            # If all targets have dependencies, add the first target as a dependent
+            # of root_node so that the cycle can be discovered from root_node.
+            target = next(iter(targets))
+            target_node = dependency_nodes[target]
+            target_node.dependencies.append(root_node)
+            root_node.dependents.append(target_node)
+
+        cycles = []
+        for cycle in root_node.FindCycles():
+            paths = [node.ref for node in cycle]
+            cycles.append("Cycle: %s" % " -> ".join(paths))
+        raise DependencyGraphNode.CircularException(
+            "Cycles in dependency graph detected:\n" + "\n".join(cycles)
+        )
+
+    return [dependency_nodes, flat_list]
+
+
+def VerifyNoGYPFileCircularDependencies(targets):
+    # Create a DependencyGraphNode for each gyp file containing a target.  Put
+    # it into a dict for easy access.
+    dependency_nodes = {}
+    for target in targets:
+        build_file = gyp.common.BuildFile(target)
+        if build_file not in dependency_nodes:
+            dependency_nodes[build_file] = DependencyGraphNode(build_file)
+
+    # Set up the dependency links.
+    for target, spec in targets.items():
+        build_file = gyp.common.BuildFile(target)
+        build_file_node = dependency_nodes[build_file]
+        target_dependencies = spec.get("dependencies", [])
+        for dependency in target_dependencies:
+            try:
+                dependency_build_file = gyp.common.BuildFile(dependency)
+            except GypError as e:
+                gyp.common.ExceptionAppend(
+                    e, "while computing dependencies of .gyp file %s" % build_file
+                )
+                raise
+
+            if dependency_build_file == build_file:
+                # A .gyp file is allowed to refer back to itself.
+                continue
+            dependency_node = dependency_nodes.get(dependency_build_file)
+            if not dependency_node:
+                raise GypError("Dependency '%s' not found" % dependency_build_file)
+            if dependency_node not in build_file_node.dependencies:
+                build_file_node.dependencies.append(dependency_node)
+                dependency_node.dependents.append(build_file_node)
+
+    # Files that have no dependencies are treated as dependent on root_node.
+    root_node = DependencyGraphNode(None)
+    for build_file_node in dependency_nodes.values():
+        if len(build_file_node.dependencies) == 0:
+            build_file_node.dependencies.append(root_node)
+            root_node.dependents.append(build_file_node)
+
+    flat_list = root_node.FlattenToList()
+
+    # If there's anything left unvisited, there must be a circular dependency
+    # (cycle).
+    if len(flat_list) != len(dependency_nodes):
+        if not root_node.dependents:
+            # If all files have dependencies, add the first file as a dependent
+            # of root_node so that the cycle can be discovered from root_node.
+            file_node = next(iter(dependency_nodes.values()))
+            file_node.dependencies.append(root_node)
+            root_node.dependents.append(file_node)
+        cycles = []
+        for cycle in root_node.FindCycles():
+            paths = [node.ref for node in cycle]
+            cycles.append("Cycle: %s" % " -> ".join(paths))
+        raise DependencyGraphNode.CircularException(
+            "Cycles in .gyp file dependency graph detected:\n" + "\n".join(cycles)
+        )
+
+
+def DoDependentSettings(key, flat_list, targets, dependency_nodes):
+    # key should be one of all_dependent_settings, direct_dependent_settings,
+    # or link_settings.
+
+    for target in flat_list:
+        target_dict = targets[target]
+        build_file = gyp.common.BuildFile(target)
+
+        if key == "all_dependent_settings":
+            dependencies = dependency_nodes[target].DeepDependencies()
+        elif key == "direct_dependent_settings":
+            dependencies = dependency_nodes[target].DirectAndImportedDependencies(
+                targets
+            )
+        elif key == "link_settings":
+            dependencies = dependency_nodes[target].DependenciesForLinkSettings(targets)
+        else:
+            raise GypError(
+                "DoDependentSettings doesn't know how to determine "
+                "dependencies for " + key
+            )
+
+        for dependency in dependencies:
+            dependency_dict = targets[dependency]
+            if key not in dependency_dict:
+                continue
+            dependency_build_file = gyp.common.BuildFile(dependency)
+            MergeDicts(
+                target_dict, dependency_dict[key], build_file, dependency_build_file
+            )
+
+
+def AdjustStaticLibraryDependencies(
+    flat_list, targets, dependency_nodes, sort_dependencies
+):
+    # Recompute target "dependencies" properties.  For each static library
+    # target, remove "dependencies" entries referring to other static libraries,
+    # unless the dependency has the "hard_dependency" attribute set.  For each
+    # linkable target, add a "dependencies" entry referring to all of the
+    # target's computed list of link dependencies (including static libraries
+    # if no such entry is already present.
+    for target in flat_list:
+        target_dict = targets[target]
+        target_type = target_dict["type"]
+
+        if target_type == "static_library":
+            if "dependencies" not in target_dict:
+                continue
+
+            target_dict["dependencies_original"] = target_dict.get("dependencies", [])[
+                :
+            ]
+
+            # A static library should not depend on another static library unless
+            # the dependency relationship is "hard," which should only be done when
+            # a dependent relies on some side effect other than just the build
+            # product, like a rule or action output. Further, if a target has a
+            # non-hard dependency, but that dependency exports a hard dependency,
+            # the non-hard dependency can safely be removed, but the exported hard
+            # dependency must be added to the target to keep the same dependency
+            # ordering.
+            dependencies = dependency_nodes[target].DirectAndImportedDependencies(
+                targets
+            )
+            index = 0
+            while index < len(dependencies):
+                dependency = dependencies[index]
+                dependency_dict = targets[dependency]
+
+                # Remove every non-hard static library dependency and remove every
+                # non-static library dependency that isn't a direct dependency.
+                if (
+                    dependency_dict["type"] == "static_library"
+                    and not dependency_dict.get("hard_dependency", False)
+                ) or (
+                    dependency_dict["type"] != "static_library"
+                    and dependency not in target_dict["dependencies"]
+                ):
+                    # Take the dependency out of the list, and don't increment index
+                    # because the next dependency to analyze will shift into the index
+                    # formerly occupied by the one being removed.
+                    del dependencies[index]
+                else:
+                    index = index + 1
+
+            # Update the dependencies. If the dependencies list is empty, it's not
+            # needed, so unhook it.
+            if len(dependencies) > 0:
+                target_dict["dependencies"] = dependencies
+            else:
+                del target_dict["dependencies"]
+
+        elif target_type in linkable_types:
+            # Get a list of dependency targets that should be linked into this
+            # target.  Add them to the dependencies list if they're not already
+            # present.
+
+            link_dependencies = dependency_nodes[target].DependenciesToLinkAgainst(
+                targets
+            )
+            for dependency in link_dependencies:
+                if dependency == target:
+                    continue
+                if "dependencies" not in target_dict:
+                    target_dict["dependencies"] = []
+                if dependency not in target_dict["dependencies"]:
+                    target_dict["dependencies"].append(dependency)
+            # Sort the dependencies list in the order from dependents to dependencies.
+            # e.g. If A and B depend on C and C depends on D, sort them in A, B, C, D.
+            # Note: flat_list is already sorted in the order from dependencies to
+            # dependents.
+            if sort_dependencies and "dependencies" in target_dict:
+                target_dict["dependencies"] = [
+                    dep
+                    for dep in reversed(flat_list)
+                    if dep in target_dict["dependencies"]
+                ]
+
+
+# Initialize this here to speed up MakePathRelative.
+exception_re = re.compile(r"""["']?[-/$<>^]""")
+
+
+def MakePathRelative(to_file, fro_file, item):
+    # If item is a relative path, it's relative to the build file dict that it's
+    # coming from.  Fix it up to make it relative to the build file dict that
+    # it's going into.
+    # Exception: any |item| that begins with these special characters is
+    # returned without modification.
+    #   /   Used when a path is already absolute (shortcut optimization;
+    #       such paths would be returned as absolute anyway)
+    #   $   Used for build environment variables
+    #   -   Used for some build environment flags (such as -lapr-1 in a
+    #       "libraries" section)
+    #   <   Used for our own variable and command expansions (see ExpandVariables)
+    #   >   Used for our own variable and command expansions (see ExpandVariables)
+    #   ^   Used for our own variable and command expansions (see ExpandVariables)
+    #
+    #   "/' Used when a value is quoted.  If these are present, then we
+    #       check the second character instead.
+    #
+    if to_file == fro_file or exception_re.match(item):
+        return item
+    else:
+        # TODO(dglazkov) The backslash/forward-slash replacement at the end is a
+        # temporary measure. This should really be addressed by keeping all paths
+        # in POSIX until actual project generation.
+        ret = os.path.normpath(
+            os.path.join(
+                gyp.common.RelativePath(
+                    os.path.dirname(fro_file), os.path.dirname(to_file)
+                ),
+                item,
+            )
+        ).replace("\\", "/")
+        if item.endswith("/"):
+            ret += "/"
+        return ret
+
+
+def MergeLists(to, fro, to_file, fro_file, is_paths=False, append=True):
+    # Python documentation recommends objects which do not support hash
+    # set this value to None. Python library objects follow this rule.
+    def is_hashable(val):
+        return val.__hash__
+
+    # If x is hashable, returns whether x is in s. Else returns whether x is in items.
+    def is_in_set_or_list(x, s, items):
+        if is_hashable(x):
+            return x in s
+        return x in items
+
+    prepend_index = 0
+
+    # Make membership testing of hashables in |to| (in particular, strings)
+    # faster.
+    hashable_to_set = {x for x in to if is_hashable(x)}
+    for item in fro:
+        singleton = False
+        if type(item) in (str, int):
+            # The cheap and easy case.
+            if is_paths:
+                to_item = MakePathRelative(to_file, fro_file, item)
+            else:
+                to_item = item
+
+            if not (type(item) is str and item.startswith("-")):
+                # Any string that doesn't begin with a "-" is a singleton - it can
+                # only appear once in a list, to be enforced by the list merge append
+                # or prepend.
+                singleton = True
+        elif type(item) is dict:
+            # Make a copy of the dictionary, continuing to look for paths to fix.
+            # The other intelligent aspects of merge processing won't apply because
+            # item is being merged into an empty dict.
+            to_item = {}
+            MergeDicts(to_item, item, to_file, fro_file)
+        elif type(item) is list:
+            # Recurse, making a copy of the list.  If the list contains any
+            # descendant dicts, path fixing will occur.  Note that here, custom
+            # values for is_paths and append are dropped; those are only to be
+            # applied to |to| and |fro|, not sublists of |fro|.  append shouldn't
+            # matter anyway because the new |to_item| list is empty.
+            to_item = []
+            MergeLists(to_item, item, to_file, fro_file)
+        else:
+            raise TypeError(
+                "Attempt to merge list item of unsupported type "
+                + item.__class__.__name__
+            )
+
+        if append:
+            # If appending a singleton that's already in the list, don't append.
+            # This ensures that the earliest occurrence of the item will stay put.
+            if not singleton or not is_in_set_or_list(to_item, hashable_to_set, to):
+                to.append(to_item)
+                if is_hashable(to_item):
+                    hashable_to_set.add(to_item)
+        else:
+            # If prepending a singleton that's already in the list, remove the
+            # existing instance and proceed with the prepend.  This ensures that the
+            # item appears at the earliest possible position in the list.
+            while singleton and to_item in to:
+                to.remove(to_item)
+
+            # Don't just insert everything at index 0.  That would prepend the new
+            # items to the list in reverse order, which would be an unwelcome
+            # surprise.
+            to.insert(prepend_index, to_item)
+            if is_hashable(to_item):
+                hashable_to_set.add(to_item)
+            prepend_index = prepend_index + 1
+
+
+def MergeDicts(to, fro, to_file, fro_file):
+    # I wanted to name the parameter "from" but it's a Python keyword...
+    for k, v in fro.items():
+        # It would be nice to do "if not k in to: to[k] = v" but that wouldn't give
+        # copy semantics.  Something else may want to merge from the |fro| dict
+        # later, and having the same dict ref pointed to twice in the tree isn't
+        # what anyone wants considering that the dicts may subsequently be
+        # modified.
+        if k in to:
+            bad_merge = False
+            if type(v) in (str, int):
+                if type(to[k]) not in (str, int):
+                    bad_merge = True
+            elif not isinstance(v, type(to[k])):
+                bad_merge = True
+
+            if bad_merge:
+                raise TypeError(
+                    "Attempt to merge dict value of type "
+                    + v.__class__.__name__
+                    + " into incompatible type "
+                    + to[k].__class__.__name__
+                    + " for key "
+                    + k
+                )
+        if type(v) in (str, int):
+            # Overwrite the existing value, if any.  Cheap and easy.
+            is_path = IsPathSection(k)
+            if is_path:
+                to[k] = MakePathRelative(to_file, fro_file, v)
+            else:
+                to[k] = v
+        elif type(v) is dict:
+            # Recurse, guaranteeing copies will be made of objects that require it.
+            if k not in to:
+                to[k] = {}
+            MergeDicts(to[k], v, to_file, fro_file)
+        elif type(v) is list:
+            # Lists in dicts can be merged with different policies, depending on
+            # how the key in the "from" dict (k, the from-key) is written.
+            #
+            # If the from-key has          ...the to-list will have this action
+            # this character appended:...     applied when receiving the from-list:
+            #                           =  replace
+            #                           +  prepend
+            #                           ?  set, only if to-list does not yet exist
+            #                      (none)  append
+            #
+            # This logic is list-specific, but since it relies on the associated
+            # dict key, it's checked in this dict-oriented function.
+            ext = k[-1]
+            append = True
+            if ext == "=":
+                list_base = k[:-1]
+                lists_incompatible = [list_base, list_base + "?"]
+                to[list_base] = []
+            elif ext == "+":
+                list_base = k[:-1]
+                lists_incompatible = [list_base + "=", list_base + "?"]
+                append = False
+            elif ext == "?":
+                list_base = k[:-1]
+                lists_incompatible = [list_base, list_base + "=", list_base + "+"]
+            else:
+                list_base = k
+                lists_incompatible = [list_base + "=", list_base + "?"]
+
+            # Some combinations of merge policies appearing together are meaningless.
+            # It's stupid to replace and append simultaneously, for example.  Append
+            # and prepend are the only policies that can coexist.
+            for list_incompatible in lists_incompatible:
+                if list_incompatible in fro:
+                    raise GypError(
+                        "Incompatible list policies " + k + " and " + list_incompatible
+                    )
+
+            if list_base in to:
+                if ext == "?":
+                    # If the key ends in "?", the list will only be merged if it doesn't
+                    # already exist.
+                    continue
+                elif type(to[list_base]) is not list:
+                    # This may not have been checked above if merging in a list with an
+                    # extension character.
+                    raise TypeError(
+                        "Attempt to merge dict value of type "
+                        + v.__class__.__name__
+                        + " into incompatible type "
+                        + to[list_base].__class__.__name__
+                        + " for key "
+                        + list_base
+                        + "("
+                        + k
+                        + ")"
+                    )
+            else:
+                to[list_base] = []
+
+            # Call MergeLists, which will make copies of objects that require it.
+            # MergeLists can recurse back into MergeDicts, although this will be
+            # to make copies of dicts (with paths fixed), there will be no
+            # subsequent dict "merging" once entering a list because lists are
+            # always replaced, appended to, or prepended to.
+            is_paths = IsPathSection(list_base)
+            MergeLists(to[list_base], v, to_file, fro_file, is_paths, append)
+        else:
+            raise TypeError(
+                "Attempt to merge dict value of unsupported type "
+                + v.__class__.__name__
+                + " for key "
+                + k
+            )
+
+
+def MergeConfigWithInheritance(
+    new_configuration_dict, build_file, target_dict, configuration, visited
+):
+    # Skip if previously visited.
+    if configuration in visited:
+        return
+
+    # Look at this configuration.
+    configuration_dict = target_dict["configurations"][configuration]
+
+    # Merge in parents.
+    for parent in configuration_dict.get("inherit_from", []):
+        MergeConfigWithInheritance(
+            new_configuration_dict,
+            build_file,
+            target_dict,
+            parent,
+            visited + [configuration],
+        )
+
+    # Merge it into the new config.
+    MergeDicts(new_configuration_dict, configuration_dict, build_file, build_file)
+
+    # Drop abstract.
+    if "abstract" in new_configuration_dict:
+        del new_configuration_dict["abstract"]
+
+
+def SetUpConfigurations(target, target_dict):
+    # key_suffixes is a list of key suffixes that might appear on key names.
+    # These suffixes are handled in conditional evaluations (for =, +, and ?)
+    # and rules/exclude processing (for ! and /).  Keys with these suffixes
+    # should be treated the same as keys without.
+    key_suffixes = ["=", "+", "?", "!", "/"]
+
+    build_file = gyp.common.BuildFile(target)
+
+    # Provide a single configuration by default if none exists.
+    # TODO(mark): Signal an error if default_configurations exists but
+    # configurations does not.
+    if "configurations" not in target_dict:
+        target_dict["configurations"] = {"Default": {}}
+    if "default_configuration" not in target_dict:
+        concrete = [
+            i
+            for (i, config) in target_dict["configurations"].items()
+            if not config.get("abstract")
+        ]
+        target_dict["default_configuration"] = sorted(concrete)[0]
+
+    merged_configurations = {}
+    configs = target_dict["configurations"]
+    for (configuration, old_configuration_dict) in configs.items():
+        # Skip abstract configurations (saves work only).
+        if old_configuration_dict.get("abstract"):
+            continue
+        # Configurations inherit (most) settings from the enclosing target scope.
+        # Get the inheritance relationship right by making a copy of the target
+        # dict.
+        new_configuration_dict = {}
+        for (key, target_val) in target_dict.items():
+            key_ext = key[-1:]
+            if key_ext in key_suffixes:
+                key_base = key[:-1]
+            else:
+                key_base = key
+            if key_base not in non_configuration_keys:
+                new_configuration_dict[key] = gyp.simple_copy.deepcopy(target_val)
+
+        # Merge in configuration (with all its parents first).
+        MergeConfigWithInheritance(
+            new_configuration_dict, build_file, target_dict, configuration, []
+        )
+
+        merged_configurations[configuration] = new_configuration_dict
+
+    # Put the new configurations back into the target dict as a configuration.
+    for configuration in merged_configurations.keys():
+        target_dict["configurations"][configuration] = merged_configurations[
+            configuration
+        ]
+
+    # Now drop all the abstract ones.
+    configs = target_dict["configurations"]
+    target_dict["configurations"] = {
+        k: v for k, v in configs.items() if not v.get("abstract")
+    }
+
+    # Now that all of the target's configurations have been built, go through
+    # the target dict's keys and remove everything that's been moved into a
+    # "configurations" section.
+    delete_keys = []
+    for key in target_dict:
+        key_ext = key[-1:]
+        if key_ext in key_suffixes:
+            key_base = key[:-1]
+        else:
+            key_base = key
+        if key_base not in non_configuration_keys:
+            delete_keys.append(key)
+    for key in delete_keys:
+        del target_dict[key]
+
+    # Check the configurations to see if they contain invalid keys.
+    for configuration in target_dict["configurations"].keys():
+        configuration_dict = target_dict["configurations"][configuration]
+        for key in configuration_dict.keys():
+            if key in invalid_configuration_keys:
+                raise GypError(
+                    "%s not allowed in the %s configuration, found in "
+                    "target %s" % (key, configuration, target)
+                )
+
+
+def ProcessListFiltersInDict(name, the_dict):
+    """Process regular expression and exclusion-based filters on lists.
+
+  An exclusion list is in a dict key named with a trailing "!", like
+  "sources!".  Every item in such a list is removed from the associated
+  main list, which in this example, would be "sources".  Removed items are
+  placed into a "sources_excluded" list in the dict.
+
+  Regular expression (regex) filters are contained in dict keys named with a
+  trailing "/", such as "sources/" to operate on the "sources" list.  Regex
+  filters in a dict take the form:
+    'sources/': [ ['exclude', '_(linux|mac|win)\\.cc$'],
+                  ['include', '_mac\\.cc$'] ],
+  The first filter says to exclude all files ending in _linux.cc, _mac.cc, and
+  _win.cc.  The second filter then includes all files ending in _mac.cc that
+  are now or were once in the "sources" list.  Items matching an "exclude"
+  filter are subject to the same processing as would occur if they were listed
+  by name in an exclusion list (ending in "!").  Items matching an "include"
+  filter are brought back into the main list if previously excluded by an
+  exclusion list or exclusion regex filter.  Subsequent matching "exclude"
+  patterns can still cause items to be excluded after matching an "include".
+  """
+
+    # Look through the dictionary for any lists whose keys end in "!" or "/".
+    # These are lists that will be treated as exclude lists and regular
+    # expression-based exclude/include lists.  Collect the lists that are
+    # needed first, looking for the lists that they operate on, and assemble
+    # then into |lists|.  This is done in a separate loop up front, because
+    # the _included and _excluded keys need to be added to the_dict, and that
+    # can't be done while iterating through it.
+
+    lists = []
+    del_lists = []
+    for key, value in the_dict.items():
+        operation = key[-1]
+        if operation != "!" and operation != "/":
+            continue
+
+        if type(value) is not list:
+            raise ValueError(
+                name + " key " + key + " must be list, not " + value.__class__.__name__
+            )
+
+        list_key = key[:-1]
+        if list_key not in the_dict:
+            # This happens when there's a list like "sources!" but no corresponding
+            # "sources" list.  Since there's nothing for it to operate on, queue up
+            # the "sources!" list for deletion now.
+            del_lists.append(key)
+            continue
+
+        if type(the_dict[list_key]) is not list:
+            value = the_dict[list_key]
+            raise ValueError(
+                name
+                + " key "
+                + list_key
+                + " must be list, not "
+                + value.__class__.__name__
+                + " when applying "
+                + {"!": "exclusion", "/": "regex"}[operation]
+            )
+
+        if list_key not in lists:
+            lists.append(list_key)
+
+    # Delete the lists that are known to be unneeded at this point.
+    for del_list in del_lists:
+        del the_dict[del_list]
+
+    for list_key in lists:
+        the_list = the_dict[list_key]
+
+        # Initialize the list_actions list, which is parallel to the_list.  Each
+        # item in list_actions identifies whether the corresponding item in
+        # the_list should be excluded, unconditionally preserved (included), or
+        # whether no exclusion or inclusion has been applied.  Items for which
+        # no exclusion or inclusion has been applied (yet) have value -1, items
+        # excluded have value 0, and items included have value 1.  Includes and
+        # excludes override previous actions.  All items in list_actions are
+        # initialized to -1 because no excludes or includes have been processed
+        # yet.
+        list_actions = list((-1,) * len(the_list))
+
+        exclude_key = list_key + "!"
+        if exclude_key in the_dict:
+            for exclude_item in the_dict[exclude_key]:
+                for index, list_item in enumerate(the_list):
+                    if exclude_item == list_item:
+                        # This item matches the exclude_item, so set its action to 0
+                        # (exclude).
+                        list_actions[index] = 0
+
+            # The "whatever!" list is no longer needed, dump it.
+            del the_dict[exclude_key]
+
+        regex_key = list_key + "/"
+        if regex_key in the_dict:
+            for regex_item in the_dict[regex_key]:
+                [action, pattern] = regex_item
+                pattern_re = re.compile(pattern)
+
+                if action == "exclude":
+                    # This item matches an exclude regex, set its value to 0 (exclude).
+                    action_value = 0
+                elif action == "include":
+                    # This item matches an include regex, set its value to 1 (include).
+                    action_value = 1
+                else:
+                    # This is an action that doesn't make any sense.
+                    raise ValueError(
+                        "Unrecognized action "
+                        + action
+                        + " in "
+                        + name
+                        + " key "
+                        + regex_key
+                    )
+
+                for index, list_item in enumerate(the_list):
+                    if list_actions[index] == action_value:
+                        # Even if the regex matches, nothing will change so continue
+                        # (regex searches are expensive).
+                        continue
+                    if pattern_re.search(list_item):
+                        # Regular expression match.
+                        list_actions[index] = action_value
+
+            # The "whatever/" list is no longer needed, dump it.
+            del the_dict[regex_key]
+
+        # Add excluded items to the excluded list.
+        #
+        # Note that exclude_key ("sources!") is different from excluded_key
+        # ("sources_excluded").  The exclude_key list is input and it was already
+        # processed and deleted; the excluded_key list is output and it's about
+        # to be created.
+        excluded_key = list_key + "_excluded"
+        if excluded_key in the_dict:
+            raise GypError(
+                name + " key " + excluded_key + " must not be present prior "
+                " to applying exclusion/regex filters for " + list_key
+            )
+
+        excluded_list = []
+
+        # Go backwards through the list_actions list so that as items are deleted,
+        # the indices of items that haven't been seen yet don't shift.  That means
+        # that things need to be prepended to excluded_list to maintain them in the
+        # same order that they existed in the_list.
+        for index in range(len(list_actions) - 1, -1, -1):
+            if list_actions[index] == 0:
+                # Dump anything with action 0 (exclude).  Keep anything with action 1
+                # (include) or -1 (no include or exclude seen for the item).
+                excluded_list.insert(0, the_list[index])
+                del the_list[index]
+
+        # If anything was excluded, put the excluded list into the_dict at
+        # excluded_key.
+        if len(excluded_list) > 0:
+            the_dict[excluded_key] = excluded_list
+
+    # Now recurse into subdicts and lists that may contain dicts.
+    for key, value in the_dict.items():
+        if type(value) is dict:
+            ProcessListFiltersInDict(key, value)
+        elif type(value) is list:
+            ProcessListFiltersInList(key, value)
+
+
+def ProcessListFiltersInList(name, the_list):
+    for item in the_list:
+        if type(item) is dict:
+            ProcessListFiltersInDict(name, item)
+        elif type(item) is list:
+            ProcessListFiltersInList(name, item)
+
+
+def ValidateTargetType(target, target_dict):
+    """Ensures the 'type' field on the target is one of the known types.
+
+  Arguments:
+    target: string, name of target.
+    target_dict: dict, target spec.
+
+  Raises an exception on error.
+  """
+    VALID_TARGET_TYPES = (
+        "executable",
+        "loadable_module",
+        "static_library",
+        "shared_library",
+        "mac_kernel_extension",
+        "none",
+        "windows_driver",
+    )
+    target_type = target_dict.get("type", None)
+    if target_type not in VALID_TARGET_TYPES:
+        raise GypError(
+            "Target %s has an invalid target type '%s'.  "
+            "Must be one of %s." % (target, target_type, "/".join(VALID_TARGET_TYPES))
+        )
+    if (
+        target_dict.get("standalone_static_library", 0)
+        and not target_type == "static_library"
+    ):
+        raise GypError(
+            "Target %s has type %s but standalone_static_library flag is"
+            " only valid for static_library type." % (target, target_type)
+        )
+
+
+def ValidateRulesInTarget(target, target_dict, extra_sources_for_rules):
+    """Ensures that the rules sections in target_dict are valid and consistent,
+  and determines which sources they apply to.
+
+  Arguments:
+    target: string, name of target.
+    target_dict: dict, target spec containing "rules" and "sources" lists.
+    extra_sources_for_rules: a list of keys to scan for rule matches in
+        addition to 'sources'.
+  """
+
+    # Dicts to map between values found in rules' 'rule_name' and 'extension'
+    # keys and the rule dicts themselves.
+    rule_names = {}
+    rule_extensions = {}
+
+    rules = target_dict.get("rules", [])
+    for rule in rules:
+        # Make sure that there's no conflict among rule names and extensions.
+        rule_name = rule["rule_name"]
+        if rule_name in rule_names:
+            raise GypError(
+                f"rule {rule_name} exists in duplicate, target {target}"
+            )
+        rule_names[rule_name] = rule
+
+        rule_extension = rule["extension"]
+        if rule_extension.startswith("."):
+            rule_extension = rule_extension[1:]
+        if rule_extension in rule_extensions:
+            raise GypError(
+                (
+                    "extension %s associated with multiple rules, "
+                    + "target %s rules %s and %s"
+                )
+                % (
+                    rule_extension,
+                    target,
+                    rule_extensions[rule_extension]["rule_name"],
+                    rule_name,
+                )
+            )
+        rule_extensions[rule_extension] = rule
+
+        # Make sure rule_sources isn't already there.  It's going to be
+        # created below if needed.
+        if "rule_sources" in rule:
+            raise GypError(
+                "rule_sources must not exist in input, target %s rule %s"
+                % (target, rule_name)
+            )
+
+        rule_sources = []
+        source_keys = ["sources"]
+        source_keys.extend(extra_sources_for_rules)
+        for source_key in source_keys:
+            for source in target_dict.get(source_key, []):
+                (source_root, source_extension) = os.path.splitext(source)
+                if source_extension.startswith("."):
+                    source_extension = source_extension[1:]
+                if source_extension == rule_extension:
+                    rule_sources.append(source)
+
+        if len(rule_sources) > 0:
+            rule["rule_sources"] = rule_sources
+
+
+def ValidateRunAsInTarget(target, target_dict, build_file):
+    target_name = target_dict.get("target_name")
+    run_as = target_dict.get("run_as")
+    if not run_as:
+        return
+    if type(run_as) is not dict:
+        raise GypError(
+            "The 'run_as' in target %s from file %s should be a "
+            "dictionary." % (target_name, build_file)
+        )
+    action = run_as.get("action")
+    if not action:
+        raise GypError(
+            "The 'run_as' in target %s from file %s must have an "
+            "'action' section." % (target_name, build_file)
+        )
+    if type(action) is not list:
+        raise GypError(
+            "The 'action' for 'run_as' in target %s from file %s "
+            "must be a list." % (target_name, build_file)
+        )
+    working_directory = run_as.get("working_directory")
+    if working_directory and type(working_directory) is not str:
+        raise GypError(
+            "The 'working_directory' for 'run_as' in target %s "
+            "in file %s should be a string." % (target_name, build_file)
+        )
+    environment = run_as.get("environment")
+    if environment and type(environment) is not dict:
+        raise GypError(
+            "The 'environment' for 'run_as' in target %s "
+            "in file %s should be a dictionary." % (target_name, build_file)
+        )
+
+
+def ValidateActionsInTarget(target, target_dict, build_file):
+    """Validates the inputs to the actions in a target."""
+    target_name = target_dict.get("target_name")
+    actions = target_dict.get("actions", [])
+    for action in actions:
+        action_name = action.get("action_name")
+        if not action_name:
+            raise GypError(
+                "Anonymous action in target %s.  "
+                "An action must have an 'action_name' field." % target_name
+            )
+        inputs = action.get("inputs", None)
+        if inputs is None:
+            raise GypError("Action in target %s has no inputs." % target_name)
+        action_command = action.get("action")
+        if action_command and not action_command[0]:
+            raise GypError("Empty action as command in target %s." % target_name)
+
+
+def TurnIntIntoStrInDict(the_dict):
+    """Given dict the_dict, recursively converts all integers into strings.
+  """
+    # Use items instead of iteritems because there's no need to try to look at
+    # reinserted keys and their associated values.
+    for k, v in the_dict.items():
+        if type(v) is int:
+            v = str(v)
+            the_dict[k] = v
+        elif type(v) is dict:
+            TurnIntIntoStrInDict(v)
+        elif type(v) is list:
+            TurnIntIntoStrInList(v)
+
+        if type(k) is int:
+            del the_dict[k]
+            the_dict[str(k)] = v
+
+
+def TurnIntIntoStrInList(the_list):
+    """Given list the_list, recursively converts all integers into strings.
+  """
+    for index, item in enumerate(the_list):
+        if type(item) is int:
+            the_list[index] = str(item)
+        elif type(item) is dict:
+            TurnIntIntoStrInDict(item)
+        elif type(item) is list:
+            TurnIntIntoStrInList(item)
+
+
+def PruneUnwantedTargets(targets, flat_list, dependency_nodes, root_targets, data):
+    """Return only the targets that are deep dependencies of |root_targets|."""
+    qualified_root_targets = []
+    for target in root_targets:
+        target = target.strip()
+        qualified_targets = gyp.common.FindQualifiedTargets(target, flat_list)
+        if not qualified_targets:
+            raise GypError("Could not find target %s" % target)
+        qualified_root_targets.extend(qualified_targets)
+
+    wanted_targets = {}
+    for target in qualified_root_targets:
+        wanted_targets[target] = targets[target]
+        for dependency in dependency_nodes[target].DeepDependencies():
+            wanted_targets[dependency] = targets[dependency]
+
+    wanted_flat_list = [t for t in flat_list if t in wanted_targets]
+
+    # Prune unwanted targets from each build_file's data dict.
+    for build_file in data["target_build_files"]:
+        if "targets" not in data[build_file]:
+            continue
+        new_targets = []
+        for target in data[build_file]["targets"]:
+            qualified_name = gyp.common.QualifiedTarget(
+                build_file, target["target_name"], target["toolset"]
+            )
+            if qualified_name in wanted_targets:
+                new_targets.append(target)
+        data[build_file]["targets"] = new_targets
+
+    return wanted_targets, wanted_flat_list
+
+
+def VerifyNoCollidingTargets(targets):
+    """Verify that no two targets in the same directory share the same name.
+
+  Arguments:
+    targets: A list of targets in the form 'path/to/file.gyp:target_name'.
+  """
+    # Keep a dict going from 'subdirectory:target_name' to 'foo.gyp'.
+    used = {}
+    for target in targets:
+        # Separate out 'path/to/file.gyp, 'target_name' from
+        # 'path/to/file.gyp:target_name'.
+        path, name = target.rsplit(":", 1)
+        # Separate out 'path/to', 'file.gyp' from 'path/to/file.gyp'.
+        subdir, gyp = os.path.split(path)
+        # Use '.' for the current directory '', so that the error messages make
+        # more sense.
+        if not subdir:
+            subdir = "."
+        # Prepare a key like 'path/to:target_name'.
+        key = subdir + ":" + name
+        if key in used:
+            # Complain if this target is already used.
+            raise GypError(
+                'Duplicate target name "%s" in directory "%s" used both '
+                'in "%s" and "%s".' % (name, subdir, gyp, used[key])
+            )
+        used[key] = gyp
+
+
+def SetGeneratorGlobals(generator_input_info):
+    # Set up path_sections and non_configuration_keys with the default data plus
+    # the generator-specific data.
+    global path_sections
+    path_sections = set(base_path_sections)
+    path_sections.update(generator_input_info["path_sections"])
+
+    global non_configuration_keys
+    non_configuration_keys = base_non_configuration_keys[:]
+    non_configuration_keys.extend(generator_input_info["non_configuration_keys"])
+
+    global multiple_toolsets
+    multiple_toolsets = generator_input_info["generator_supports_multiple_toolsets"]
+
+    global generator_filelist_paths
+    generator_filelist_paths = generator_input_info["generator_filelist_paths"]
+
+
+def Load(
+    build_files,
+    variables,
+    includes,
+    depth,
+    generator_input_info,
+    check,
+    circular_check,
+    parallel,
+    root_targets,
+):
+    SetGeneratorGlobals(generator_input_info)
+    # A generator can have other lists (in addition to sources) be processed
+    # for rules.
+    extra_sources_for_rules = generator_input_info["extra_sources_for_rules"]
+
+    # Load build files.  This loads every target-containing build file into
+    # the |data| dictionary such that the keys to |data| are build file names,
+    # and the values are the entire build file contents after "early" or "pre"
+    # processing has been done and includes have been resolved.
+    # NOTE: data contains both "target" files (.gyp) and "includes" (.gypi), as
+    # well as meta-data (e.g. 'included_files' key). 'target_build_files' keeps
+    # track of the keys corresponding to "target" files.
+    data = {"target_build_files": set()}
+    # Normalize paths everywhere.  This is important because paths will be
+    # used as keys to the data dict and for references between input files.
+    build_files = set(map(os.path.normpath, build_files))
+    if parallel:
+        LoadTargetBuildFilesParallel(
+            build_files, data, variables, includes, depth, check, generator_input_info
+        )
+    else:
+        aux_data = {}
+        for build_file in build_files:
+            try:
+                LoadTargetBuildFile(
+                    build_file, data, aux_data, variables, includes, depth, check, True
+                )
+            except Exception as e:
+                gyp.common.ExceptionAppend(e, "while trying to load %s" % build_file)
+                raise
+
+    # Build a dict to access each target's subdict by qualified name.
+    targets = BuildTargetsDict(data)
+
+    # Fully qualify all dependency links.
+    QualifyDependencies(targets)
+
+    # Remove self-dependencies from targets that have 'prune_self_dependencies'
+    # set to 1.
+    RemoveSelfDependencies(targets)
+
+    # Expand dependencies specified as build_file:*.
+    ExpandWildcardDependencies(targets, data)
+
+    # Remove all dependencies marked as 'link_dependency' from the targets of
+    # type 'none'.
+    RemoveLinkDependenciesFromNoneTargets(targets)
+
+    # Apply exclude (!) and regex (/) list filters only for dependency_sections.
+    for target_name, target_dict in targets.items():
+        tmp_dict = {}
+        for key_base in dependency_sections:
+            for op in ("", "!", "/"):
+                key = key_base + op
+                if key in target_dict:
+                    tmp_dict[key] = target_dict[key]
+                    del target_dict[key]
+        ProcessListFiltersInDict(target_name, tmp_dict)
+        # Write the results back to |target_dict|.
+        for key in tmp_dict:
+            target_dict[key] = tmp_dict[key]
+
+    # Make sure every dependency appears at most once.
+    RemoveDuplicateDependencies(targets)
+
+    if circular_check:
+        # Make sure that any targets in a.gyp don't contain dependencies in other
+        # .gyp files that further depend on a.gyp.
+        VerifyNoGYPFileCircularDependencies(targets)
+
+    [dependency_nodes, flat_list] = BuildDependencyList(targets)
+
+    if root_targets:
+        # Remove, from |targets| and |flat_list|, the targets that are not deep
+        # dependencies of the targets specified in |root_targets|.
+        targets, flat_list = PruneUnwantedTargets(
+            targets, flat_list, dependency_nodes, root_targets, data
+        )
+
+    # Check that no two targets in the same directory have the same name.
+    VerifyNoCollidingTargets(flat_list)
+
+    # Handle dependent settings of various types.
+    for settings_type in [
+        "all_dependent_settings",
+        "direct_dependent_settings",
+        "link_settings",
+    ]:
+        DoDependentSettings(settings_type, flat_list, targets, dependency_nodes)
+
+        # Take out the dependent settings now that they've been published to all
+        # of the targets that require them.
+        for target in flat_list:
+            if settings_type in targets[target]:
+                del targets[target][settings_type]
+
+    # Make sure static libraries don't declare dependencies on other static
+    # libraries, but that linkables depend on all unlinked static libraries
+    # that they need so that their link steps will be correct.
+    gii = generator_input_info
+    if gii["generator_wants_static_library_dependencies_adjusted"]:
+        AdjustStaticLibraryDependencies(
+            flat_list,
+            targets,
+            dependency_nodes,
+            gii["generator_wants_sorted_dependencies"],
+        )
+
+    # Apply "post"/"late"/"target" variable expansions and condition evaluations.
+    for target in flat_list:
+        target_dict = targets[target]
+        build_file = gyp.common.BuildFile(target)
+        ProcessVariablesAndConditionsInDict(
+            target_dict, PHASE_LATE, variables, build_file
+        )
+
+    # Move everything that can go into a "configurations" section into one.
+    for target in flat_list:
+        target_dict = targets[target]
+        SetUpConfigurations(target, target_dict)
+
+    # Apply exclude (!) and regex (/) list filters.
+    for target in flat_list:
+        target_dict = targets[target]
+        ProcessListFiltersInDict(target, target_dict)
+
+    # Apply "latelate" variable expansions and condition evaluations.
+    for target in flat_list:
+        target_dict = targets[target]
+        build_file = gyp.common.BuildFile(target)
+        ProcessVariablesAndConditionsInDict(
+            target_dict, PHASE_LATELATE, variables, build_file
+        )
+
+    # Make sure that the rules make sense, and build up rule_sources lists as
+    # needed.  Not all generators will need to use the rule_sources lists, but
+    # some may, and it seems best to build the list in a common spot.
+    # Also validate actions and run_as elements in targets.
+    for target in flat_list:
+        target_dict = targets[target]
+        build_file = gyp.common.BuildFile(target)
+        ValidateTargetType(target, target_dict)
+        ValidateRulesInTarget(target, target_dict, extra_sources_for_rules)
+        ValidateRunAsInTarget(target, target_dict, build_file)
+        ValidateActionsInTarget(target, target_dict, build_file)
+
+    # Generators might not expect ints.  Turn them into strs.
+    TurnIntIntoStrInDict(data)
+
+    # TODO(mark): Return |data| for now because the generator needs a list of
+    # build files that came in.  In the future, maybe it should just accept
+    # a list, and not the whole data dict.
+    return [flat_list, targets, data]
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/input_test.py b/server/node_modules/node-gyp/gyp/pylib/gyp/input_test.py
new file mode 100755
index 0000000..a18f72e
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/input_test.py
@@ -0,0 +1,98 @@
+#!/usr/bin/env python3
+
+# Copyright 2013 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Unit tests for the input.py file."""
+
+import gyp.input
+import unittest
+
+
+class TestFindCycles(unittest.TestCase):
+    def setUp(self):
+        self.nodes = {}
+        for x in ("a", "b", "c", "d", "e"):
+            self.nodes[x] = gyp.input.DependencyGraphNode(x)
+
+    def _create_dependency(self, dependent, dependency):
+        dependent.dependencies.append(dependency)
+        dependency.dependents.append(dependent)
+
+    def test_no_cycle_empty_graph(self):
+        for label, node in self.nodes.items():
+            self.assertEqual([], node.FindCycles())
+
+    def test_no_cycle_line(self):
+        self._create_dependency(self.nodes["a"], self.nodes["b"])
+        self._create_dependency(self.nodes["b"], self.nodes["c"])
+        self._create_dependency(self.nodes["c"], self.nodes["d"])
+
+        for label, node in self.nodes.items():
+            self.assertEqual([], node.FindCycles())
+
+    def test_no_cycle_dag(self):
+        self._create_dependency(self.nodes["a"], self.nodes["b"])
+        self._create_dependency(self.nodes["a"], self.nodes["c"])
+        self._create_dependency(self.nodes["b"], self.nodes["c"])
+
+        for label, node in self.nodes.items():
+            self.assertEqual([], node.FindCycles())
+
+    def test_cycle_self_reference(self):
+        self._create_dependency(self.nodes["a"], self.nodes["a"])
+
+        self.assertEqual(
+            [[self.nodes["a"], self.nodes["a"]]], self.nodes["a"].FindCycles()
+        )
+
+    def test_cycle_two_nodes(self):
+        self._create_dependency(self.nodes["a"], self.nodes["b"])
+        self._create_dependency(self.nodes["b"], self.nodes["a"])
+
+        self.assertEqual(
+            [[self.nodes["a"], self.nodes["b"], self.nodes["a"]]],
+            self.nodes["a"].FindCycles(),
+        )
+        self.assertEqual(
+            [[self.nodes["b"], self.nodes["a"], self.nodes["b"]]],
+            self.nodes["b"].FindCycles(),
+        )
+
+    def test_two_cycles(self):
+        self._create_dependency(self.nodes["a"], self.nodes["b"])
+        self._create_dependency(self.nodes["b"], self.nodes["a"])
+
+        self._create_dependency(self.nodes["b"], self.nodes["c"])
+        self._create_dependency(self.nodes["c"], self.nodes["b"])
+
+        cycles = self.nodes["a"].FindCycles()
+        self.assertTrue([self.nodes["a"], self.nodes["b"], self.nodes["a"]] in cycles)
+        self.assertTrue([self.nodes["b"], self.nodes["c"], self.nodes["b"]] in cycles)
+        self.assertEqual(2, len(cycles))
+
+    def test_big_cycle(self):
+        self._create_dependency(self.nodes["a"], self.nodes["b"])
+        self._create_dependency(self.nodes["b"], self.nodes["c"])
+        self._create_dependency(self.nodes["c"], self.nodes["d"])
+        self._create_dependency(self.nodes["d"], self.nodes["e"])
+        self._create_dependency(self.nodes["e"], self.nodes["a"])
+
+        self.assertEqual(
+            [
+                [
+                    self.nodes["a"],
+                    self.nodes["b"],
+                    self.nodes["c"],
+                    self.nodes["d"],
+                    self.nodes["e"],
+                    self.nodes["a"],
+                ]
+            ],
+            self.nodes["a"].FindCycles(),
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/mac_tool.py b/server/node_modules/node-gyp/gyp/pylib/gyp/mac_tool.py
new file mode 100755
index 0000000..59647c9
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/mac_tool.py
@@ -0,0 +1,771 @@
+#!/usr/bin/env python3
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Utility functions to perform Xcode-style build steps.
+
+These functions are executed via gyp-mac-tool when using the Makefile generator.
+"""
+
+
+import fcntl
+import fnmatch
+import glob
+import json
+import os
+import plistlib
+import re
+import shutil
+import struct
+import subprocess
+import sys
+import tempfile
+
+
+def main(args):
+    executor = MacTool()
+    exit_code = executor.Dispatch(args)
+    if exit_code is not None:
+        sys.exit(exit_code)
+
+
+class MacTool:
+    """This class performs all the Mac tooling steps. The methods can either be
+  executed directly, or dispatched from an argument list."""
+
+    def Dispatch(self, args):
+        """Dispatches a string command to a method."""
+        if len(args) < 1:
+            raise Exception("Not enough arguments")
+
+        method = "Exec%s" % self._CommandifyName(args[0])
+        return getattr(self, method)(*args[1:])
+
+    def _CommandifyName(self, name_string):
+        """Transforms a tool name like copy-info-plist to CopyInfoPlist"""
+        return name_string.title().replace("-", "")
+
+    def ExecCopyBundleResource(self, source, dest, convert_to_binary):
+        """Copies a resource file to the bundle/Resources directory, performing any
+    necessary compilation on each resource."""
+        convert_to_binary = convert_to_binary == "True"
+        extension = os.path.splitext(source)[1].lower()
+        if os.path.isdir(source):
+            # Copy tree.
+            # TODO(thakis): This copies file attributes like mtime, while the
+            # single-file branch below doesn't. This should probably be changed to
+            # be consistent with the single-file branch.
+            if os.path.exists(dest):
+                shutil.rmtree(dest)
+            shutil.copytree(source, dest)
+        elif extension == ".xib":
+            return self._CopyXIBFile(source, dest)
+        elif extension == ".storyboard":
+            return self._CopyXIBFile(source, dest)
+        elif extension == ".strings" and not convert_to_binary:
+            self._CopyStringsFile(source, dest)
+        else:
+            if os.path.exists(dest):
+                os.unlink(dest)
+            shutil.copy(source, dest)
+
+        if convert_to_binary and extension in (".plist", ".strings"):
+            self._ConvertToBinary(dest)
+
+    def _CopyXIBFile(self, source, dest):
+        """Compiles a XIB file with ibtool into a binary plist in the bundle."""
+
+        # ibtool sometimes crashes with relative paths. See crbug.com/314728.
+        base = os.path.dirname(os.path.realpath(__file__))
+        if os.path.relpath(source):
+            source = os.path.join(base, source)
+        if os.path.relpath(dest):
+            dest = os.path.join(base, dest)
+
+        args = ["xcrun", "ibtool", "--errors", "--warnings", "--notices"]
+
+        if os.environ["XCODE_VERSION_ACTUAL"] > "0700":
+            args.extend(["--auto-activate-custom-fonts"])
+            if "IPHONEOS_DEPLOYMENT_TARGET" in os.environ:
+                args.extend(
+                    [
+                        "--target-device",
+                        "iphone",
+                        "--target-device",
+                        "ipad",
+                        "--minimum-deployment-target",
+                        os.environ["IPHONEOS_DEPLOYMENT_TARGET"],
+                    ]
+                )
+            else:
+                args.extend(
+                    [
+                        "--target-device",
+                        "mac",
+                        "--minimum-deployment-target",
+                        os.environ["MACOSX_DEPLOYMENT_TARGET"],
+                    ]
+                )
+
+        args.extend(
+            ["--output-format", "human-readable-text", "--compile", dest, source]
+        )
+
+        ibtool_section_re = re.compile(r"/\*.*\*/")
+        ibtool_re = re.compile(r".*note:.*is clipping its content")
+        try:
+            stdout = subprocess.check_output(args)
+        except subprocess.CalledProcessError as e:
+            print(e.output)
+            raise
+        current_section_header = None
+        for line in stdout.splitlines():
+            if ibtool_section_re.match(line):
+                current_section_header = line
+            elif not ibtool_re.match(line):
+                if current_section_header:
+                    print(current_section_header)
+                    current_section_header = None
+                print(line)
+        return 0
+
+    def _ConvertToBinary(self, dest):
+        subprocess.check_call(
+            ["xcrun", "plutil", "-convert", "binary1", "-o", dest, dest]
+        )
+
+    def _CopyStringsFile(self, source, dest):
+        """Copies a .strings file using iconv to reconvert the input into UTF-16."""
+        input_code = self._DetectInputEncoding(source) or "UTF-8"
+
+        # Xcode's CpyCopyStringsFile / builtin-copyStrings seems to call
+        # CFPropertyListCreateFromXMLData() behind the scenes; at least it prints
+        #     CFPropertyListCreateFromXMLData(): Old-style plist parser: missing
+        #     semicolon in dictionary.
+        # on invalid files. Do the same kind of validation.
+        import CoreFoundation
+
+        with open(source, "rb") as in_file:
+            s = in_file.read()
+        d = CoreFoundation.CFDataCreate(None, s, len(s))
+        _, error = CoreFoundation.CFPropertyListCreateFromXMLData(None, d, 0, None)
+        if error:
+            return
+
+        with open(dest, "wb") as fp:
+            fp.write(s.decode(input_code).encode("UTF-16"))
+
+    def _DetectInputEncoding(self, file_name):
+        """Reads the first few bytes from file_name and tries to guess the text
+    encoding. Returns None as a guess if it can't detect it."""
+        with open(file_name, "rb") as fp:
+            try:
+                header = fp.read(3)
+            except Exception:
+                return None
+        if header.startswith(b"\xFE\xFF"):
+            return "UTF-16"
+        elif header.startswith(b"\xFF\xFE"):
+            return "UTF-16"
+        elif header.startswith(b"\xEF\xBB\xBF"):
+            return "UTF-8"
+        else:
+            return None
+
+    def ExecCopyInfoPlist(self, source, dest, convert_to_binary, *keys):
+        """Copies the |source| Info.plist to the destination directory |dest|."""
+        # Read the source Info.plist into memory.
+        with open(source) as fd:
+            lines = fd.read()
+
+        # Insert synthesized key/value pairs (e.g. BuildMachineOSBuild).
+        plist = plistlib.readPlistFromString(lines)
+        if keys:
+            plist.update(json.loads(keys[0]))
+        lines = plistlib.writePlistToString(plist)
+
+        # Go through all the environment variables and replace them as variables in
+        # the file.
+        IDENT_RE = re.compile(r"[_/\s]")
+        for key in os.environ:
+            if key.startswith("_"):
+                continue
+            evar = "${%s}" % key
+            evalue = os.environ[key]
+            lines = lines.replace(lines, evar, evalue)
+
+            # Xcode supports various suffices on environment variables, which are
+            # all undocumented. :rfc1034identifier is used in the standard project
+            # template these days, and :identifier was used earlier. They are used to
+            # convert non-url characters into things that look like valid urls --
+            # except that the replacement character for :identifier, '_' isn't valid
+            # in a URL either -- oops, hence :rfc1034identifier was born.
+            evar = "${%s:identifier}" % key
+            evalue = IDENT_RE.sub("_", os.environ[key])
+            lines = lines.replace(lines, evar, evalue)
+
+            evar = "${%s:rfc1034identifier}" % key
+            evalue = IDENT_RE.sub("-", os.environ[key])
+            lines = lines.replace(lines, evar, evalue)
+
+        # Remove any keys with values that haven't been replaced.
+        lines = lines.splitlines()
+        for i in range(len(lines)):
+            if lines[i].strip().startswith("<string>${"):
+                lines[i] = None
+                lines[i - 1] = None
+        lines = "\n".join(line for line in lines if line is not None)
+
+        # Write out the file with variables replaced.
+        with open(dest, "w") as fd:
+            fd.write(lines)
+
+        # Now write out PkgInfo file now that the Info.plist file has been
+        # "compiled".
+        self._WritePkgInfo(dest)
+
+        if convert_to_binary == "True":
+            self._ConvertToBinary(dest)
+
+    def _WritePkgInfo(self, info_plist):
+        """This writes the PkgInfo file from the data stored in Info.plist."""
+        plist = plistlib.readPlist(info_plist)
+        if not plist:
+            return
+
+        # Only create PkgInfo for executable types.
+        package_type = plist["CFBundlePackageType"]
+        if package_type != "APPL":
+            return
+
+        # The format of PkgInfo is eight characters, representing the bundle type
+        # and bundle signature, each four characters. If that is missing, four
+        # '?' characters are used instead.
+        signature_code = plist.get("CFBundleSignature", "????")
+        if len(signature_code) != 4:  # Wrong length resets everything, too.
+            signature_code = "?" * 4
+
+        dest = os.path.join(os.path.dirname(info_plist), "PkgInfo")
+        with open(dest, "w") as fp:
+            fp.write(f"{package_type}{signature_code}")
+
+    def ExecFlock(self, lockfile, *cmd_list):
+        """Emulates the most basic behavior of Linux's flock(1)."""
+        # Rely on exception handling to report errors.
+        fd = os.open(lockfile, os.O_RDONLY | os.O_NOCTTY | os.O_CREAT, 0o666)
+        fcntl.flock(fd, fcntl.LOCK_EX)
+        return subprocess.call(cmd_list)
+
+    def ExecFilterLibtool(self, *cmd_list):
+        """Calls libtool and filters out '/path/to/libtool: file: foo.o has no
+    symbols'."""
+        libtool_re = re.compile(
+            r"^.*libtool: (?:for architecture: \S* )?" r"file: .* has no symbols$"
+        )
+        libtool_re5 = re.compile(
+            r"^.*libtool: warning for library: "
+            + r".* the table of contents is empty "
+            + r"$no object file members in the library define global symbols$$"
+        )
+        env = os.environ.copy()
+        # Ref:
+        # http://www.opensource.apple.com/source/cctools/cctools-809/misc/libtool.c
+        # The problem with this flag is that it resets the file mtime on the file to
+        # epoch=0, e.g. 1970-1-1 or 1969-12-31 depending on timezone.
+        env["ZERO_AR_DATE"] = "1"
+        libtoolout = subprocess.Popen(cmd_list, stderr=subprocess.PIPE, env=env)
+        err = libtoolout.communicate()[1].decode("utf-8")
+        for line in err.splitlines():
+            if not libtool_re.match(line) and not libtool_re5.match(line):
+                print(line, file=sys.stderr)
+        # Unconditionally touch the output .a file on the command line if present
+        # and the command succeeded. A bit hacky.
+        if not libtoolout.returncode:
+            for i in range(len(cmd_list) - 1):
+                if cmd_list[i] == "-o" and cmd_list[i + 1].endswith(".a"):
+                    os.utime(cmd_list[i + 1], None)
+                    break
+        return libtoolout.returncode
+
+    def ExecPackageIosFramework(self, framework):
+        # Find the name of the binary based on the part before the ".framework".
+        binary = os.path.basename(framework).split(".")[0]
+        module_path = os.path.join(framework, "Modules")
+        if not os.path.exists(module_path):
+            os.mkdir(module_path)
+        module_template = (
+            "framework module %s {\n"
+            '  umbrella header "%s.h"\n'
+            "\n"
+            "  export *\n"
+            "  module * { export * }\n"
+            "}\n" % (binary, binary)
+        )
+
+        with open(os.path.join(module_path, "module.modulemap"), "w") as module_file:
+            module_file.write(module_template)
+
+    def ExecPackageFramework(self, framework, version):
+        """Takes a path to Something.framework and the Current version of that and
+    sets up all the symlinks."""
+        # Find the name of the binary based on the part before the ".framework".
+        binary = os.path.basename(framework).split(".")[0]
+
+        CURRENT = "Current"
+        RESOURCES = "Resources"
+        VERSIONS = "Versions"
+
+        if not os.path.exists(os.path.join(framework, VERSIONS, version, binary)):
+            # Binary-less frameworks don't seem to contain symlinks (see e.g.
+            # chromium's out/Debug/org.chromium.Chromium.manifest/ bundle).
+            return
+
+        # Move into the framework directory to set the symlinks correctly.
+        pwd = os.getcwd()
+        os.chdir(framework)
+
+        # Set up the Current version.
+        self._Relink(version, os.path.join(VERSIONS, CURRENT))
+
+        # Set up the root symlinks.
+        self._Relink(os.path.join(VERSIONS, CURRENT, binary), binary)
+        self._Relink(os.path.join(VERSIONS, CURRENT, RESOURCES), RESOURCES)
+
+        # Back to where we were before!
+        os.chdir(pwd)
+
+    def _Relink(self, dest, link):
+        """Creates a symlink to |dest| named |link|. If |link| already exists,
+    it is overwritten."""
+        if os.path.lexists(link):
+            os.remove(link)
+        os.symlink(dest, link)
+
+    def ExecCompileIosFrameworkHeaderMap(self, out, framework, *all_headers):
+        framework_name = os.path.basename(framework).split(".")[0]
+        all_headers = [os.path.abspath(header) for header in all_headers]
+        filelist = {}
+        for header in all_headers:
+            filename = os.path.basename(header)
+            filelist[filename] = header
+            filelist[os.path.join(framework_name, filename)] = header
+        WriteHmap(out, filelist)
+
+    def ExecCopyIosFrameworkHeaders(self, framework, *copy_headers):
+        header_path = os.path.join(framework, "Headers")
+        if not os.path.exists(header_path):
+            os.makedirs(header_path)
+        for header in copy_headers:
+            shutil.copy(header, os.path.join(header_path, os.path.basename(header)))
+
+    def ExecCompileXcassets(self, keys, *inputs):
+        """Compiles multiple .xcassets files into a single .car file.
+
+    This invokes 'actool' to compile all the inputs .xcassets files. The
+    |keys| arguments is a json-encoded dictionary of extra arguments to
+    pass to 'actool' when the asset catalogs contains an application icon
+    or a launch image.
+
+    Note that 'actool' does not create the Assets.car file if the asset
+    catalogs does not contains imageset.
+    """
+        command_line = [
+            "xcrun",
+            "actool",
+            "--output-format",
+            "human-readable-text",
+            "--compress-pngs",
+            "--notices",
+            "--warnings",
+            "--errors",
+        ]
+        is_iphone_target = "IPHONEOS_DEPLOYMENT_TARGET" in os.environ
+        if is_iphone_target:
+            platform = os.environ["CONFIGURATION"].split("-")[-1]
+            if platform not in ("iphoneos", "iphonesimulator"):
+                platform = "iphonesimulator"
+            command_line.extend(
+                [
+                    "--platform",
+                    platform,
+                    "--target-device",
+                    "iphone",
+                    "--target-device",
+                    "ipad",
+                    "--minimum-deployment-target",
+                    os.environ["IPHONEOS_DEPLOYMENT_TARGET"],
+                    "--compile",
+                    os.path.abspath(os.environ["CONTENTS_FOLDER_PATH"]),
+                ]
+            )
+        else:
+            command_line.extend(
+                [
+                    "--platform",
+                    "macosx",
+                    "--target-device",
+                    "mac",
+                    "--minimum-deployment-target",
+                    os.environ["MACOSX_DEPLOYMENT_TARGET"],
+                    "--compile",
+                    os.path.abspath(os.environ["UNLOCALIZED_RESOURCES_FOLDER_PATH"]),
+                ]
+            )
+        if keys:
+            keys = json.loads(keys)
+            for key, value in keys.items():
+                arg_name = "--" + key
+                if isinstance(value, bool):
+                    if value:
+                        command_line.append(arg_name)
+                elif isinstance(value, list):
+                    for v in value:
+                        command_line.append(arg_name)
+                        command_line.append(str(v))
+                else:
+                    command_line.append(arg_name)
+                    command_line.append(str(value))
+        # Note: actool crashes if inputs path are relative, so use os.path.abspath
+        # to get absolute path name for inputs.
+        command_line.extend(map(os.path.abspath, inputs))
+        subprocess.check_call(command_line)
+
+    def ExecMergeInfoPlist(self, output, *inputs):
+        """Merge multiple .plist files into a single .plist file."""
+        merged_plist = {}
+        for path in inputs:
+            plist = self._LoadPlistMaybeBinary(path)
+            self._MergePlist(merged_plist, plist)
+        plistlib.writePlist(merged_plist, output)
+
+    def ExecCodeSignBundle(self, key, entitlements, provisioning, path, preserve):
+        """Code sign a bundle.
+
+    This function tries to code sign an iOS bundle, following the same
+    algorithm as Xcode:
+      1. pick the provisioning profile that best match the bundle identifier,
+         and copy it into the bundle as embedded.mobileprovision,
+      2. copy Entitlements.plist from user or SDK next to the bundle,
+      3. code sign the bundle.
+    """
+        substitutions, overrides = self._InstallProvisioningProfile(
+            provisioning, self._GetCFBundleIdentifier()
+        )
+        entitlements_path = self._InstallEntitlements(
+            entitlements, substitutions, overrides
+        )
+
+        args = ["codesign", "--force", "--sign", key]
+        if preserve == "True":
+            args.extend(["--deep", "--preserve-metadata=identifier,entitlements"])
+        else:
+            args.extend(["--entitlements", entitlements_path])
+        args.extend(["--timestamp=none", path])
+        subprocess.check_call(args)
+
+    def _InstallProvisioningProfile(self, profile, bundle_identifier):
+        """Installs embedded.mobileprovision into the bundle.
+
+    Args:
+      profile: string, optional, short name of the .mobileprovision file
+        to use, if empty or the file is missing, the best file installed
+        will be used
+      bundle_identifier: string, value of CFBundleIdentifier from Info.plist
+
+    Returns:
+      A tuple containing two dictionary: variables substitutions and values
+      to overrides when generating the entitlements file.
+    """
+        source_path, provisioning_data, team_id = self._FindProvisioningProfile(
+            profile, bundle_identifier
+        )
+        target_path = os.path.join(
+            os.environ["BUILT_PRODUCTS_DIR"],
+            os.environ["CONTENTS_FOLDER_PATH"],
+            "embedded.mobileprovision",
+        )
+        shutil.copy2(source_path, target_path)
+        substitutions = self._GetSubstitutions(bundle_identifier, team_id + ".")
+        return substitutions, provisioning_data["Entitlements"]
+
+    def _FindProvisioningProfile(self, profile, bundle_identifier):
+        """Finds the .mobileprovision file to use for signing the bundle.
+
+    Checks all the installed provisioning profiles (or if the user specified
+    the PROVISIONING_PROFILE variable, only consult it) and select the most
+    specific that correspond to the bundle identifier.
+
+    Args:
+      profile: string, optional, short name of the .mobileprovision file
+        to use, if empty or the file is missing, the best file installed
+        will be used
+      bundle_identifier: string, value of CFBundleIdentifier from Info.plist
+
+    Returns:
+      A tuple of the path to the selected provisioning profile, the data of
+      the embedded plist in the provisioning profile and the team identifier
+      to use for code signing.
+
+    Raises:
+      SystemExit: if no .mobileprovision can be used to sign the bundle.
+    """
+        profiles_dir = os.path.join(
+            os.environ["HOME"], "Library", "MobileDevice", "Provisioning Profiles"
+        )
+        if not os.path.isdir(profiles_dir):
+            print(
+                "cannot find mobile provisioning for %s" % (bundle_identifier),
+                file=sys.stderr,
+            )
+            sys.exit(1)
+        provisioning_profiles = None
+        if profile:
+            profile_path = os.path.join(profiles_dir, profile + ".mobileprovision")
+            if os.path.exists(profile_path):
+                provisioning_profiles = [profile_path]
+        if not provisioning_profiles:
+            provisioning_profiles = glob.glob(
+                os.path.join(profiles_dir, "*.mobileprovision")
+            )
+        valid_provisioning_profiles = {}
+        for profile_path in provisioning_profiles:
+            profile_data = self._LoadProvisioningProfile(profile_path)
+            app_id_pattern = profile_data.get("Entitlements", {}).get(
+                "application-identifier", ""
+            )
+            for team_identifier in profile_data.get("TeamIdentifier", []):
+                app_id = f"{team_identifier}.{bundle_identifier}"
+                if fnmatch.fnmatch(app_id, app_id_pattern):
+                    valid_provisioning_profiles[app_id_pattern] = (
+                        profile_path,
+                        profile_data,
+                        team_identifier,
+                    )
+        if not valid_provisioning_profiles:
+            print(
+                "cannot find mobile provisioning for %s" % (bundle_identifier),
+                file=sys.stderr,
+            )
+            sys.exit(1)
+        # If the user has multiple provisioning profiles installed that can be
+        # used for ${bundle_identifier}, pick the most specific one (ie. the
+        # provisioning profile whose pattern is the longest).
+        selected_key = max(valid_provisioning_profiles, key=lambda v: len(v))
+        return valid_provisioning_profiles[selected_key]
+
+    def _LoadProvisioningProfile(self, profile_path):
+        """Extracts the plist embedded in a provisioning profile.
+
+    Args:
+      profile_path: string, path to the .mobileprovision file
+
+    Returns:
+      Content of the plist embedded in the provisioning profile as a dictionary.
+    """
+        with tempfile.NamedTemporaryFile() as temp:
+            subprocess.check_call(
+                ["security", "cms", "-D", "-i", profile_path, "-o", temp.name]
+            )
+            return self._LoadPlistMaybeBinary(temp.name)
+
+    def _MergePlist(self, merged_plist, plist):
+        """Merge |plist| into |merged_plist|."""
+        for key, value in plist.items():
+            if isinstance(value, dict):
+                merged_value = merged_plist.get(key, {})
+                if isinstance(merged_value, dict):
+                    self._MergePlist(merged_value, value)
+                    merged_plist[key] = merged_value
+                else:
+                    merged_plist[key] = value
+            else:
+                merged_plist[key] = value
+
+    def _LoadPlistMaybeBinary(self, plist_path):
+        """Loads into a memory a plist possibly encoded in binary format.
+
+    This is a wrapper around plistlib.readPlist that tries to convert the
+    plist to the XML format if it can't be parsed (assuming that it is in
+    the binary format).
+
+    Args:
+      plist_path: string, path to a plist file, in XML or binary format
+
+    Returns:
+      Content of the plist as a dictionary.
+    """
+        try:
+            # First, try to read the file using plistlib that only supports XML,
+            # and if an exception is raised, convert a temporary copy to XML and
+            # load that copy.
+            return plistlib.readPlist(plist_path)
+        except Exception:
+            pass
+        with tempfile.NamedTemporaryFile() as temp:
+            shutil.copy2(plist_path, temp.name)
+            subprocess.check_call(["plutil", "-convert", "xml1", temp.name])
+            return plistlib.readPlist(temp.name)
+
+    def _GetSubstitutions(self, bundle_identifier, app_identifier_prefix):
+        """Constructs a dictionary of variable substitutions for Entitlements.plist.
+
+    Args:
+      bundle_identifier: string, value of CFBundleIdentifier from Info.plist
+      app_identifier_prefix: string, value for AppIdentifierPrefix
+
+    Returns:
+      Dictionary of substitutions to apply when generating Entitlements.plist.
+    """
+        return {
+            "CFBundleIdentifier": bundle_identifier,
+            "AppIdentifierPrefix": app_identifier_prefix,
+        }
+
+    def _GetCFBundleIdentifier(self):
+        """Extracts CFBundleIdentifier value from Info.plist in the bundle.
+
+    Returns:
+      Value of CFBundleIdentifier in the Info.plist located in the bundle.
+    """
+        info_plist_path = os.path.join(
+            os.environ["TARGET_BUILD_DIR"], os.environ["INFOPLIST_PATH"]
+        )
+        info_plist_data = self._LoadPlistMaybeBinary(info_plist_path)
+        return info_plist_data["CFBundleIdentifier"]
+
+    def _InstallEntitlements(self, entitlements, substitutions, overrides):
+        """Generates and install the ${BundleName}.xcent entitlements file.
+
+    Expands variables "$(variable)" pattern in the source entitlements file,
+    add extra entitlements defined in the .mobileprovision file and the copy
+    the generated plist to "${BundlePath}.xcent".
+
+    Args:
+      entitlements: string, optional, path to the Entitlements.plist template
+        to use, defaults to "${SDKROOT}/Entitlements.plist"
+      substitutions: dictionary, variable substitutions
+      overrides: dictionary, values to add to the entitlements
+
+    Returns:
+      Path to the generated entitlements file.
+    """
+        source_path = entitlements
+        target_path = os.path.join(
+            os.environ["BUILT_PRODUCTS_DIR"], os.environ["PRODUCT_NAME"] + ".xcent"
+        )
+        if not source_path:
+            source_path = os.path.join(os.environ["SDKROOT"], "Entitlements.plist")
+        shutil.copy2(source_path, target_path)
+        data = self._LoadPlistMaybeBinary(target_path)
+        data = self._ExpandVariables(data, substitutions)
+        if overrides:
+            for key in overrides:
+                if key not in data:
+                    data[key] = overrides[key]
+        plistlib.writePlist(data, target_path)
+        return target_path
+
+    def _ExpandVariables(self, data, substitutions):
+        """Expands variables "$(variable)" in data.
+
+    Args:
+      data: object, can be either string, list or dictionary
+      substitutions: dictionary, variable substitutions to perform
+
+    Returns:
+      Copy of data where each references to "$(variable)" has been replaced
+      by the corresponding value found in substitutions, or left intact if
+      the key was not found.
+    """
+        if isinstance(data, str):
+            for key, value in substitutions.items():
+                data = data.replace("$(%s)" % key, value)
+            return data
+        if isinstance(data, list):
+            return [self._ExpandVariables(v, substitutions) for v in data]
+        if isinstance(data, dict):
+            return {k: self._ExpandVariables(data[k], substitutions) for k in data}
+        return data
+
+
+def NextGreaterPowerOf2(x):
+    return 2 ** (x).bit_length()
+
+
+def WriteHmap(output_name, filelist):
+    """Generates a header map based on |filelist|.
+
+  Per Mark Mentovai:
+    A header map is structured essentially as a hash table, keyed by names used
+    in #includes, and providing pathnames to the actual files.
+
+  The implementation below and the comment above comes from inspecting:
+    http://www.opensource.apple.com/source/distcc/distcc-2503/distcc_dist/include_server/headermap.py?txt
+  while also looking at the implementation in clang in:
+    https://llvm.org/svn/llvm-project/cfe/trunk/lib/Lex/HeaderMap.cpp
+  """
+    magic = 1751998832
+    version = 1
+    _reserved = 0
+    count = len(filelist)
+    capacity = NextGreaterPowerOf2(count)
+    strings_offset = 24 + (12 * capacity)
+    max_value_length = max(len(value) for value in filelist.values())
+
+    out = open(output_name, "wb")
+    out.write(
+        struct.pack(
+            "<LHHLLLL",
+            magic,
+            version,
+            _reserved,
+            strings_offset,
+            count,
+            capacity,
+            max_value_length,
+        )
+    )
+
+    # Create empty hashmap buckets.
+    buckets = [None] * capacity
+    for file, path in filelist.items():
+        key = 0
+        for c in file:
+            key += ord(c.lower()) * 13
+
+        # Fill next empty bucket.
+        while buckets[key & capacity - 1] is not None:
+            key = key + 1
+        buckets[key & capacity - 1] = (file, path)
+
+    next_offset = 1
+    for bucket in buckets:
+        if bucket is None:
+            out.write(struct.pack("<LLL", 0, 0, 0))
+        else:
+            (file, path) = bucket
+            key_offset = next_offset
+            prefix_offset = key_offset + len(file) + 1
+            suffix_offset = prefix_offset + len(os.path.dirname(path) + os.sep) + 1
+            next_offset = suffix_offset + len(os.path.basename(path)) + 1
+            out.write(struct.pack("<LLL", key_offset, prefix_offset, suffix_offset))
+
+    # Pad byte since next offset starts at 1.
+    out.write(struct.pack("<x"))
+
+    for bucket in buckets:
+        if bucket is not None:
+            (file, path) = bucket
+            out.write(struct.pack("<%ds" % len(file), file))
+            out.write(struct.pack("<s", "\0"))
+            base = os.path.dirname(path) + os.sep
+            out.write(struct.pack("<%ds" % len(base), base))
+            out.write(struct.pack("<s", "\0"))
+            path = os.path.basename(path)
+            out.write(struct.pack("<%ds" % len(path), path))
+            out.write(struct.pack("<s", "\0"))
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/msvs_emulation.py b/server/node_modules/node-gyp/gyp/pylib/gyp/msvs_emulation.py
new file mode 100644
index 0000000..5b9c271
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/msvs_emulation.py
@@ -0,0 +1,1271 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+This module helps emulate Visual Studio 2008 behavior on top of other
+build systems, primarily ninja.
+"""
+
+import collections
+import os
+import re
+import subprocess
+import sys
+
+from gyp.common import OrderedSet
+import gyp.MSVSUtil
+import gyp.MSVSVersion
+
+windows_quoter_regex = re.compile(r'(\\*)"')
+
+
+def QuoteForRspFile(arg, quote_cmd=True):
+    """Quote a command line argument so that it appears as one argument when
+    processed via cmd.exe and parsed by CommandLineToArgvW (as is typical for
+    Windows programs)."""
+    # See http://goo.gl/cuFbX and http://goo.gl/dhPnp including the comment
+    # threads. This is actually the quoting rules for CommandLineToArgvW, not
+    # for the shell, because the shell doesn't do anything in Windows. This
+    # works more or less because most programs (including the compiler, etc.)
+    # use that function to handle command line arguments.
+
+    # Use a heuristic to try to find args that are paths, and normalize them
+    if arg.find("/") > 0 or arg.count("/") > 1:
+        arg = os.path.normpath(arg)
+
+    # For a literal quote, CommandLineToArgvW requires 2n+1 backslashes
+    # preceding it, and results in n backslashes + the quote. So we substitute
+    # in 2* what we match, +1 more, plus the quote.
+    if quote_cmd:
+        arg = windows_quoter_regex.sub(lambda mo: 2 * mo.group(1) + '\\"', arg)
+
+    # %'s also need to be doubled otherwise they're interpreted as batch
+    # positional arguments. Also make sure to escape the % so that they're
+    # passed literally through escaping so they can be singled to just the
+    # original %. Otherwise, trying to pass the literal representation that
+    # looks like an environment variable to the shell (e.g. %PATH%) would fail.
+    arg = arg.replace("%", "%%")
+
+    # These commands are used in rsp files, so no escaping for the shell (via ^)
+    # is necessary.
+
+    # As a workaround for programs that don't use CommandLineToArgvW, gyp
+    # supports msvs_quote_cmd=0, which simply disables all quoting.
+    if quote_cmd:
+        # Finally, wrap the whole thing in quotes so that the above quote rule
+        # applies and whitespace isn't a word break.
+        return f'"{arg}"'
+
+    return arg
+
+
+def EncodeRspFileList(args, quote_cmd):
+    """Process a list of arguments using QuoteCmdExeArgument."""
+    # Note that the first argument is assumed to be the command. Don't add
+    # quotes around it because then built-ins like 'echo', etc. won't work.
+    # Take care to normpath only the path in the case of 'call ../x.bat' because
+    # otherwise the whole thing is incorrectly interpreted as a path and not
+    # normalized correctly.
+    if not args:
+        return ""
+    if args[0].startswith("call "):
+        call, program = args[0].split(" ", 1)
+        program = call + " " + os.path.normpath(program)
+    else:
+        program = os.path.normpath(args[0])
+    return (program + " "
+            + " ".join(QuoteForRspFile(arg, quote_cmd) for arg in args[1:]))
+
+
+def _GenericRetrieve(root, default, path):
+    """Given a list of dictionary keys |path| and a tree of dicts |root|, find
+    value at path, or return |default| if any of the path doesn't exist."""
+    if not root:
+        return default
+    if not path:
+        return root
+    return _GenericRetrieve(root.get(path[0]), default, path[1:])
+
+
+def _AddPrefix(element, prefix):
+    """Add |prefix| to |element| or each subelement if element is iterable."""
+    if element is None:
+        return element
+    # Note, not Iterable because we don't want to handle strings like that.
+    if isinstance(element, list) or isinstance(element, tuple):
+        return [prefix + e for e in element]
+    else:
+        return prefix + element
+
+
+def _DoRemapping(element, map):
+    """If |element| then remap it through |map|. If |element| is iterable then
+    each item will be remapped. Any elements not found will be removed."""
+    if map is not None and element is not None:
+        if not callable(map):
+            map = map.get  # Assume it's a dict, otherwise a callable to do the remap.
+        if isinstance(element, list) or isinstance(element, tuple):
+            element = filter(None, [map(elem) for elem in element])
+        else:
+            element = map(element)
+    return element
+
+
+def _AppendOrReturn(append, element):
+    """If |append| is None, simply return |element|. If |append| is not None,
+    then add |element| to it, adding each item in |element| if it's a list or
+    tuple."""
+    if append is not None and element is not None:
+        if isinstance(element, list) or isinstance(element, tuple):
+            append.extend(element)
+        else:
+            append.append(element)
+    else:
+        return element
+
+
+def _FindDirectXInstallation():
+    """Try to find an installation location for the DirectX SDK. Check for the
+    standard environment variable, and if that doesn't exist, try to find
+    via the registry. May return None if not found in either location."""
+    # Return previously calculated value, if there is one
+    if hasattr(_FindDirectXInstallation, "dxsdk_dir"):
+        return _FindDirectXInstallation.dxsdk_dir
+
+    dxsdk_dir = os.environ.get("DXSDK_DIR")
+    if not dxsdk_dir:
+        # Setup params to pass to and attempt to launch reg.exe.
+        cmd = ["reg.exe", "query", r"HKLM\Software\Microsoft\DirectX", "/s"]
+        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        stdout = p.communicate()[0].decode("utf-8")
+        for line in stdout.splitlines():
+            if "InstallPath" in line:
+                dxsdk_dir = line.split("    ")[3] + "\\"
+
+    # Cache return value
+    _FindDirectXInstallation.dxsdk_dir = dxsdk_dir
+    return dxsdk_dir
+
+
+def GetGlobalVSMacroEnv(vs_version):
+    """Get a dict of variables mapping internal VS macro names to their gyp
+    equivalents. Returns all variables that are independent of the target."""
+    env = {}
+    # '$(VSInstallDir)' and '$(VCInstallDir)' are available when and only when
+    # Visual Studio is actually installed.
+    if vs_version.Path():
+        env["$(VSInstallDir)"] = vs_version.Path()
+        env["$(VCInstallDir)"] = os.path.join(vs_version.Path(), "VC") + "\\"
+    # Chromium uses DXSDK_DIR in include/lib paths, but it may or may not be
+    # set. This happens when the SDK is sync'd via src-internal, rather than
+    # by typical end-user installation of the SDK. If it's not set, we don't
+    # want to leave the unexpanded variable in the path, so simply strip it.
+    dxsdk_dir = _FindDirectXInstallation()
+    env["$(DXSDK_DIR)"] = dxsdk_dir if dxsdk_dir else ""
+    # Try to find an installation location for the Windows DDK by checking
+    # the WDK_DIR environment variable, may be None.
+    env["$(WDK_DIR)"] = os.environ.get("WDK_DIR", "")
+    return env
+
+
+def ExtractSharedMSVSSystemIncludes(configs, generator_flags):
+    """Finds msvs_system_include_dirs that are common to all targets, removes
+    them from all targets, and returns an OrderedSet containing them."""
+    all_system_includes = OrderedSet(configs[0].get("msvs_system_include_dirs", []))
+    for config in configs[1:]:
+        system_includes = config.get("msvs_system_include_dirs", [])
+        all_system_includes = all_system_includes & OrderedSet(system_includes)
+    if not all_system_includes:
+        return None
+    # Expand macros in all_system_includes.
+    env = GetGlobalVSMacroEnv(GetVSVersion(generator_flags))
+    expanded_system_includes = OrderedSet(
+        [ExpandMacros(include, env) for include in all_system_includes]
+    )
+    if any(["$" in include for include in expanded_system_includes]):
+        # Some path relies on target-specific variables, bail.
+        return None
+
+    # Remove system includes shared by all targets from the targets.
+    for config in configs:
+        includes = config.get("msvs_system_include_dirs", [])
+        if includes:  # Don't insert a msvs_system_include_dirs key if not needed.
+            # This must check the unexpanded includes list:
+            new_includes = [i for i in includes if i not in all_system_includes]
+            config["msvs_system_include_dirs"] = new_includes
+    return expanded_system_includes
+
+
+class MsvsSettings:
+    """A class that understands the gyp 'msvs_...' values (especially the
+    msvs_settings field). They largely correpond to the VS2008 IDE DOM. This
+    class helps map those settings to command line options."""
+
+    def __init__(self, spec, generator_flags):
+        self.spec = spec
+        self.vs_version = GetVSVersion(generator_flags)
+
+        supported_fields = [
+            ("msvs_configuration_attributes", dict),
+            ("msvs_settings", dict),
+            ("msvs_system_include_dirs", list),
+            ("msvs_disabled_warnings", list),
+            ("msvs_precompiled_header", str),
+            ("msvs_precompiled_source", str),
+            ("msvs_configuration_platform", str),
+            ("msvs_target_platform", str),
+        ]
+        configs = spec["configurations"]
+        for field, default in supported_fields:
+            setattr(self, field, {})
+            for configname, config in configs.items():
+                getattr(self, field)[configname] = config.get(field, default())
+
+        self.msvs_cygwin_dirs = spec.get("msvs_cygwin_dirs", ["."])
+
+        unsupported_fields = [
+            "msvs_prebuild",
+            "msvs_postbuild",
+        ]
+        unsupported = []
+        for field in unsupported_fields:
+            for config in configs.values():
+                if field in config:
+                    unsupported += [
+                        "{} not supported (target {}).".format(
+                            field, spec["target_name"]
+                        )
+                    ]
+        if unsupported:
+            raise Exception("\n".join(unsupported))
+
+    def GetExtension(self):
+        """Returns the extension for the target, with no leading dot.
+
+        Uses 'product_extension' if specified, otherwise uses MSVS defaults based on
+        the target type.
+        """
+        ext = self.spec.get("product_extension", None)
+        if ext:
+            return ext
+        return gyp.MSVSUtil.TARGET_TYPE_EXT.get(self.spec["type"], "")
+
+    def GetVSMacroEnv(self, base_to_build=None, config=None):
+        """Get a dict of variables mapping internal VS macro names to their gyp
+        equivalents."""
+        target_arch = self.GetArch(config)
+        if target_arch == "x86":
+            target_platform = "Win32"
+        else:
+            target_platform = target_arch
+        target_name = self.spec.get("product_prefix", "") + self.spec.get(
+            "product_name", self.spec["target_name"]
+        )
+        target_dir = base_to_build + "\\" if base_to_build else ""
+        target_ext = "." + self.GetExtension()
+        target_file_name = target_name + target_ext
+
+        replacements = {
+            "$(InputName)": "${root}",
+            "$(InputPath)": "${source}",
+            "$(IntDir)": "$!INTERMEDIATE_DIR",
+            "$(OutDir)\\": target_dir,
+            "$(PlatformName)": target_platform,
+            "$(ProjectDir)\\": "",
+            "$(ProjectName)": self.spec["target_name"],
+            "$(TargetDir)\\": target_dir,
+            "$(TargetExt)": target_ext,
+            "$(TargetFileName)": target_file_name,
+            "$(TargetName)": target_name,
+            "$(TargetPath)": os.path.join(target_dir, target_file_name),
+        }
+        replacements.update(GetGlobalVSMacroEnv(self.vs_version))
+        return replacements
+
+    def ConvertVSMacros(self, s, base_to_build=None, config=None):
+        """Convert from VS macro names to something equivalent."""
+        env = self.GetVSMacroEnv(base_to_build, config=config)
+        return ExpandMacros(s, env)
+
+    def AdjustLibraries(self, libraries):
+        """Strip -l from library if it's specified with that."""
+        libs = [lib[2:] if lib.startswith("-l") else lib for lib in libraries]
+        return [
+            lib + ".lib"
+            if not lib.lower().endswith(".lib") and not lib.lower().endswith(".obj")
+            else lib
+            for lib in libs
+        ]
+
+    def _GetAndMunge(self, field, path, default, prefix, append, map):
+        """Retrieve a value from |field| at |path| or return |default|. If
+        |append| is specified, and the item is found, it will be appended to that
+        object instead of returned. If |map| is specified, results will be
+        remapped through |map| before being returned or appended."""
+        result = _GenericRetrieve(field, default, path)
+        result = _DoRemapping(result, map)
+        result = _AddPrefix(result, prefix)
+        return _AppendOrReturn(append, result)
+
+    class _GetWrapper:
+        def __init__(self, parent, field, base_path, append=None):
+            self.parent = parent
+            self.field = field
+            self.base_path = [base_path]
+            self.append = append
+
+        def __call__(self, name, map=None, prefix="", default=None):
+            return self.parent._GetAndMunge(
+                self.field,
+                self.base_path + [name],
+                default=default,
+                prefix=prefix,
+                append=self.append,
+                map=map,
+            )
+
+    def GetArch(self, config):
+        """Get architecture based on msvs_configuration_platform and
+        msvs_target_platform. Returns either 'x86' or 'x64'."""
+        configuration_platform = self.msvs_configuration_platform.get(config, "")
+        platform = self.msvs_target_platform.get(config, "")
+        if not platform:  # If no specific override, use the configuration's.
+            platform = configuration_platform
+        # Map from platform to architecture.
+        return {"Win32": "x86", "x64": "x64", "ARM64": "arm64"}.get(platform, "x86")
+
+    def _TargetConfig(self, config):
+        """Returns the target-specific configuration."""
+        # There's two levels of architecture/platform specification in VS. The
+        # first level is globally for the configuration (this is what we consider
+        # "the" config at the gyp level, which will be something like 'Debug' or
+        # 'Release'), VS2015 and later only use this level
+        if int(self.vs_version.short_name) >= 2015:
+            return config
+        # and a second target-specific configuration, which is an
+        # override for the global one. |config| is remapped here to take into
+        # account the local target-specific overrides to the global configuration.
+        arch = self.GetArch(config)
+        if arch == "x64" and not config.endswith("_x64"):
+            config += "_x64"
+        if arch == "x86" and config.endswith("_x64"):
+            config = config.rsplit("_", 1)[0]
+        return config
+
+    def _Setting(self, path, config, default=None, prefix="", append=None, map=None):
+        """_GetAndMunge for msvs_settings."""
+        return self._GetAndMunge(
+            self.msvs_settings[config], path, default, prefix, append, map
+        )
+
+    def _ConfigAttrib(
+        self, path, config, default=None, prefix="", append=None, map=None
+    ):
+        """_GetAndMunge for msvs_configuration_attributes."""
+        return self._GetAndMunge(
+            self.msvs_configuration_attributes[config],
+            path,
+            default,
+            prefix,
+            append,
+            map,
+        )
+
+    def AdjustIncludeDirs(self, include_dirs, config):
+        """Updates include_dirs to expand VS specific paths, and adds the system
+        include dirs used for platform SDK and similar."""
+        config = self._TargetConfig(config)
+        includes = include_dirs + self.msvs_system_include_dirs[config]
+        includes.extend(
+            self._Setting(
+                ("VCCLCompilerTool", "AdditionalIncludeDirectories"), config, default=[]
+            )
+        )
+        return [self.ConvertVSMacros(p, config=config) for p in includes]
+
+    def AdjustMidlIncludeDirs(self, midl_include_dirs, config):
+        """Updates midl_include_dirs to expand VS specific paths, and adds the
+        system include dirs used for platform SDK and similar."""
+        config = self._TargetConfig(config)
+        includes = midl_include_dirs + self.msvs_system_include_dirs[config]
+        includes.extend(
+            self._Setting(
+                ("VCMIDLTool", "AdditionalIncludeDirectories"), config, default=[]
+            )
+        )
+        return [self.ConvertVSMacros(p, config=config) for p in includes]
+
+    def GetComputedDefines(self, config):
+        """Returns the set of defines that are injected to the defines list based
+        on other VS settings."""
+        config = self._TargetConfig(config)
+        defines = []
+        if self._ConfigAttrib(["CharacterSet"], config) == "1":
+            defines.extend(("_UNICODE", "UNICODE"))
+        if self._ConfigAttrib(["CharacterSet"], config) == "2":
+            defines.append("_MBCS")
+        defines.extend(
+            self._Setting(
+                ("VCCLCompilerTool", "PreprocessorDefinitions"), config, default=[]
+            )
+        )
+        return defines
+
+    def GetCompilerPdbName(self, config, expand_special):
+        """Get the pdb file name that should be used for compiler invocations, or
+        None if there's no explicit name specified."""
+        config = self._TargetConfig(config)
+        pdbname = self._Setting(("VCCLCompilerTool", "ProgramDataBaseFileName"), config)
+        if pdbname:
+            pdbname = expand_special(self.ConvertVSMacros(pdbname))
+        return pdbname
+
+    def GetMapFileName(self, config, expand_special):
+        """Gets the explicitly overridden map file name for a target or returns None
+        if it's not set."""
+        config = self._TargetConfig(config)
+        map_file = self._Setting(("VCLinkerTool", "MapFileName"), config)
+        if map_file:
+            map_file = expand_special(self.ConvertVSMacros(map_file, config=config))
+        return map_file
+
+    def GetOutputName(self, config, expand_special):
+        """Gets the explicitly overridden output name for a target or returns None
+        if it's not overridden."""
+        config = self._TargetConfig(config)
+        type = self.spec["type"]
+        root = "VCLibrarianTool" if type == "static_library" else "VCLinkerTool"
+        # TODO(scottmg): Handle OutputDirectory without OutputFile.
+        output_file = self._Setting((root, "OutputFile"), config)
+        if output_file:
+            output_file = expand_special(
+                self.ConvertVSMacros(output_file, config=config)
+            )
+        return output_file
+
+    def GetPDBName(self, config, expand_special, default):
+        """Gets the explicitly overridden pdb name for a target or returns
+        default if it's not overridden, or if no pdb will be generated."""
+        config = self._TargetConfig(config)
+        output_file = self._Setting(("VCLinkerTool", "ProgramDatabaseFile"), config)
+        generate_debug_info = self._Setting(
+            ("VCLinkerTool", "GenerateDebugInformation"), config
+        )
+        if generate_debug_info == "true":
+            if output_file:
+                return expand_special(self.ConvertVSMacros(output_file, config=config))
+            else:
+                return default
+        else:
+            return None
+
+    def GetNoImportLibrary(self, config):
+        """If NoImportLibrary: true, ninja will not expect the output to include
+        an import library."""
+        config = self._TargetConfig(config)
+        noimplib = self._Setting(("NoImportLibrary",), config)
+        return noimplib == "true"
+
+    def GetAsmflags(self, config):
+        """Returns the flags that need to be added to ml invocations."""
+        config = self._TargetConfig(config)
+        asmflags = []
+        safeseh = self._Setting(("MASM", "UseSafeExceptionHandlers"), config)
+        if safeseh == "true":
+            asmflags.append("/safeseh")
+        return asmflags
+
+    def GetCflags(self, config):
+        """Returns the flags that need to be added to .c and .cc compilations."""
+        config = self._TargetConfig(config)
+        cflags = []
+        cflags.extend(["/wd" + w for w in self.msvs_disabled_warnings[config]])
+        cl = self._GetWrapper(
+            self, self.msvs_settings[config], "VCCLCompilerTool", append=cflags
+        )
+        cl(
+            "Optimization",
+            map={"0": "d", "1": "1", "2": "2", "3": "x"},
+            prefix="/O",
+            default="2",
+        )
+        cl("InlineFunctionExpansion", prefix="/Ob")
+        cl("DisableSpecificWarnings", prefix="/wd")
+        cl("StringPooling", map={"true": "/GF"})
+        cl("EnableFiberSafeOptimizations", map={"true": "/GT"})
+        cl("OmitFramePointers", map={"false": "-", "true": ""}, prefix="/Oy")
+        cl("EnableIntrinsicFunctions", map={"false": "-", "true": ""}, prefix="/Oi")
+        cl("FavorSizeOrSpeed", map={"1": "t", "2": "s"}, prefix="/O")
+        cl(
+            "FloatingPointModel",
+            map={"0": "precise", "1": "strict", "2": "fast"},
+            prefix="/fp:",
+            default="0",
+        )
+        cl("CompileAsManaged", map={"false": "", "true": "/clr"})
+        cl("WholeProgramOptimization", map={"true": "/GL"})
+        cl("WarningLevel", prefix="/W")
+        cl("WarnAsError", map={"true": "/WX"})
+        cl(
+            "CallingConvention",
+            map={"0": "d", "1": "r", "2": "z", "3": "v"},
+            prefix="/G",
+        )
+        cl("DebugInformationFormat", map={"1": "7", "3": "i", "4": "I"}, prefix="/Z")
+        cl("RuntimeTypeInfo", map={"true": "/GR", "false": "/GR-"})
+        cl("EnableFunctionLevelLinking", map={"true": "/Gy", "false": "/Gy-"})
+        cl("MinimalRebuild", map={"true": "/Gm"})
+        cl("BufferSecurityCheck", map={"true": "/GS", "false": "/GS-"})
+        cl("BasicRuntimeChecks", map={"1": "s", "2": "u", "3": "1"}, prefix="/RTC")
+        cl(
+            "RuntimeLibrary",
+            map={"0": "T", "1": "Td", "2": "D", "3": "Dd"},
+            prefix="/M",
+        )
+        cl("ExceptionHandling", map={"1": "sc", "2": "a"}, prefix="/EH")
+        cl("DefaultCharIsUnsigned", map={"true": "/J"})
+        cl(
+            "TreatWChar_tAsBuiltInType",
+            map={"false": "-", "true": ""},
+            prefix="/Zc:wchar_t",
+        )
+        cl("EnablePREfast", map={"true": "/analyze"})
+        cl("AdditionalOptions", prefix="")
+        cl(
+            "EnableEnhancedInstructionSet",
+            map={"1": "SSE", "2": "SSE2", "3": "AVX", "4": "IA32", "5": "AVX2"},
+            prefix="/arch:",
+        )
+        cflags.extend(
+            [
+                "/FI" + f
+                for f in self._Setting(
+                    ("VCCLCompilerTool", "ForcedIncludeFiles"), config, default=[]
+                )
+            ]
+        )
+        if float(self.vs_version.project_version) >= 12.0:
+            # New flag introduced in VS2013 (project version 12.0) Forces writes to
+            # the program database (PDB) to be serialized through MSPDBSRV.EXE.
+            # https://msdn.microsoft.com/en-us/library/dn502518.aspx
+            cflags.append("/FS")
+        # ninja handles parallelism by itself, don't have the compiler do it too.
+        cflags = [x for x in cflags if not x.startswith("/MP")]
+        return cflags
+
+    def _GetPchFlags(self, config, extension):
+        """Get the flags to be added to the cflags for precompiled header support."""
+        config = self._TargetConfig(config)
+        # The PCH is only built once by a particular source file. Usage of PCH must
+        # only be for the same language (i.e. C vs. C++), so only include the pch
+        # flags when the language matches.
+        if self.msvs_precompiled_header[config]:
+            source_ext = os.path.splitext(self.msvs_precompiled_source[config])[1]
+            if _LanguageMatchesForPch(source_ext, extension):
+                pch = self.msvs_precompiled_header[config]
+                pchbase = os.path.split(pch)[1]
+                return ["/Yu" + pch, "/FI" + pch, "/Fp${pchprefix}." + pchbase + ".pch"]
+        return []
+
+    def GetCflagsC(self, config):
+        """Returns the flags that need to be added to .c compilations."""
+        config = self._TargetConfig(config)
+        return self._GetPchFlags(config, ".c")
+
+    def GetCflagsCC(self, config):
+        """Returns the flags that need to be added to .cc compilations."""
+        config = self._TargetConfig(config)
+        return ["/TP"] + self._GetPchFlags(config, ".cc")
+
+    def _GetAdditionalLibraryDirectories(self, root, config, gyp_to_build_path):
+        """Get and normalize the list of paths in AdditionalLibraryDirectories
+        setting."""
+        config = self._TargetConfig(config)
+        libpaths = self._Setting(
+            (root, "AdditionalLibraryDirectories"), config, default=[]
+        )
+        libpaths = [
+            os.path.normpath(gyp_to_build_path(self.ConvertVSMacros(p, config=config)))
+            for p in libpaths
+        ]
+        return ['/LIBPATH:"' + p + '"' for p in libpaths]
+
+    def GetLibFlags(self, config, gyp_to_build_path):
+        """Returns the flags that need to be added to lib commands."""
+        config = self._TargetConfig(config)
+        libflags = []
+        lib = self._GetWrapper(
+            self, self.msvs_settings[config], "VCLibrarianTool", append=libflags
+        )
+        libflags.extend(
+            self._GetAdditionalLibraryDirectories(
+                "VCLibrarianTool", config, gyp_to_build_path
+            )
+        )
+        lib("LinkTimeCodeGeneration", map={"true": "/LTCG"})
+        lib(
+            "TargetMachine",
+            map={"1": "X86", "17": "X64", "3": "ARM"},
+            prefix="/MACHINE:",
+        )
+        lib("AdditionalOptions")
+        return libflags
+
+    def GetDefFile(self, gyp_to_build_path):
+        """Returns the .def file from sources, if any.  Otherwise returns None."""
+        spec = self.spec
+        if spec["type"] in ("shared_library", "loadable_module", "executable"):
+            def_files = [
+                s for s in spec.get("sources", []) if s.lower().endswith(".def")
+            ]
+            if len(def_files) == 1:
+                return gyp_to_build_path(def_files[0])
+            elif len(def_files) > 1:
+                raise Exception("Multiple .def files")
+        return None
+
+    def _GetDefFileAsLdflags(self, ldflags, gyp_to_build_path):
+        """.def files get implicitly converted to a ModuleDefinitionFile for the
+        linker in the VS generator. Emulate that behaviour here."""
+        def_file = self.GetDefFile(gyp_to_build_path)
+        if def_file:
+            ldflags.append('/DEF:"%s"' % def_file)
+
+    def GetPGDName(self, config, expand_special):
+        """Gets the explicitly overridden pgd name for a target or returns None
+        if it's not overridden."""
+        config = self._TargetConfig(config)
+        output_file = self._Setting(("VCLinkerTool", "ProfileGuidedDatabase"), config)
+        if output_file:
+            output_file = expand_special(
+                self.ConvertVSMacros(output_file, config=config)
+            )
+        return output_file
+
+    def GetLdflags(
+        self,
+        config,
+        gyp_to_build_path,
+        expand_special,
+        manifest_base_name,
+        output_name,
+        is_executable,
+        build_dir,
+    ):
+        """Returns the flags that need to be added to link commands, and the
+        manifest files."""
+        config = self._TargetConfig(config)
+        ldflags = []
+        ld = self._GetWrapper(
+            self, self.msvs_settings[config], "VCLinkerTool", append=ldflags
+        )
+        self._GetDefFileAsLdflags(ldflags, gyp_to_build_path)
+        ld("GenerateDebugInformation", map={"true": "/DEBUG"})
+        # TODO: These 'map' values come from machineTypeOption enum,
+        # and does not have an official value for ARM64 in VS2017 (yet).
+        # It needs to verify the ARM64 value when machineTypeOption is updated.
+        ld(
+            "TargetMachine",
+            map={"1": "X86", "17": "X64", "3": "ARM", "18": "ARM64"},
+            prefix="/MACHINE:",
+        )
+        ldflags.extend(
+            self._GetAdditionalLibraryDirectories(
+                "VCLinkerTool", config, gyp_to_build_path
+            )
+        )
+        ld("DelayLoadDLLs", prefix="/DELAYLOAD:")
+        ld("TreatLinkerWarningAsErrors", prefix="/WX", map={"true": "", "false": ":NO"})
+        out = self.GetOutputName(config, expand_special)
+        if out:
+            ldflags.append("/OUT:" + out)
+        pdb = self.GetPDBName(config, expand_special, output_name + ".pdb")
+        if pdb:
+            ldflags.append("/PDB:" + pdb)
+        pgd = self.GetPGDName(config, expand_special)
+        if pgd:
+            ldflags.append("/PGD:" + pgd)
+        map_file = self.GetMapFileName(config, expand_special)
+        ld("GenerateMapFile", map={"true": "/MAP:" + map_file if map_file else "/MAP"})
+        ld("MapExports", map={"true": "/MAPINFO:EXPORTS"})
+        ld("AdditionalOptions", prefix="")
+
+        minimum_required_version = self._Setting(
+            ("VCLinkerTool", "MinimumRequiredVersion"), config, default=""
+        )
+        if minimum_required_version:
+            minimum_required_version = "," + minimum_required_version
+        ld(
+            "SubSystem",
+            map={
+                "1": "CONSOLE%s" % minimum_required_version,
+                "2": "WINDOWS%s" % minimum_required_version,
+            },
+            prefix="/SUBSYSTEM:",
+        )
+
+        stack_reserve_size = self._Setting(
+            ("VCLinkerTool", "StackReserveSize"), config, default=""
+        )
+        if stack_reserve_size:
+            stack_commit_size = self._Setting(
+                ("VCLinkerTool", "StackCommitSize"), config, default=""
+            )
+            if stack_commit_size:
+                stack_commit_size = "," + stack_commit_size
+            ldflags.append(f"/STACK:{stack_reserve_size}{stack_commit_size}")
+
+        ld("TerminalServerAware", map={"1": ":NO", "2": ""}, prefix="/TSAWARE")
+        ld("LinkIncremental", map={"1": ":NO", "2": ""}, prefix="/INCREMENTAL")
+        ld("BaseAddress", prefix="/BASE:")
+        ld("FixedBaseAddress", map={"1": ":NO", "2": ""}, prefix="/FIXED")
+        ld("RandomizedBaseAddress", map={"1": ":NO", "2": ""}, prefix="/DYNAMICBASE")
+        ld("DataExecutionPrevention", map={"1": ":NO", "2": ""}, prefix="/NXCOMPAT")
+        ld("OptimizeReferences", map={"1": "NOREF", "2": "REF"}, prefix="/OPT:")
+        ld("ForceSymbolReferences", prefix="/INCLUDE:")
+        ld("EnableCOMDATFolding", map={"1": "NOICF", "2": "ICF"}, prefix="/OPT:")
+        ld(
+            "LinkTimeCodeGeneration",
+            map={"1": "", "2": ":PGINSTRUMENT", "3": ":PGOPTIMIZE", "4": ":PGUPDATE"},
+            prefix="/LTCG",
+        )
+        ld("IgnoreDefaultLibraryNames", prefix="/NODEFAULTLIB:")
+        ld("ResourceOnlyDLL", map={"true": "/NOENTRY"})
+        ld("EntryPointSymbol", prefix="/ENTRY:")
+        ld("Profile", map={"true": "/PROFILE"})
+        ld("LargeAddressAware", map={"1": ":NO", "2": ""}, prefix="/LARGEADDRESSAWARE")
+        # TODO(scottmg): This should sort of be somewhere else (not really a flag).
+        ld("AdditionalDependencies", prefix="")
+
+        if self.GetArch(config) == "x86":
+            safeseh_default = "true"
+        else:
+            safeseh_default = None
+        ld(
+            "ImageHasSafeExceptionHandlers",
+            map={"false": ":NO", "true": ""},
+            prefix="/SAFESEH",
+            default=safeseh_default,
+        )
+
+        # If the base address is not specifically controlled, DYNAMICBASE should
+        # be on by default.
+        if not any("DYNAMICBASE" in flag or flag == "/FIXED" for flag in ldflags):
+            ldflags.append("/DYNAMICBASE")
+
+        # If the NXCOMPAT flag has not been specified, default to on. Despite the
+        # documentation that says this only defaults to on when the subsystem is
+        # Vista or greater (which applies to the linker), the IDE defaults it on
+        # unless it's explicitly off.
+        if not any("NXCOMPAT" in flag for flag in ldflags):
+            ldflags.append("/NXCOMPAT")
+
+        have_def_file = any(flag.startswith("/DEF:") for flag in ldflags)
+        (
+            manifest_flags,
+            intermediate_manifest,
+            manifest_files,
+        ) = self._GetLdManifestFlags(
+            config,
+            manifest_base_name,
+            gyp_to_build_path,
+            is_executable and not have_def_file,
+            build_dir,
+        )
+        ldflags.extend(manifest_flags)
+        return ldflags, intermediate_manifest, manifest_files
+
+    def _GetLdManifestFlags(
+        self, config, name, gyp_to_build_path, allow_isolation, build_dir
+    ):
+        """Returns a 3-tuple:
+        - the set of flags that need to be added to the link to generate
+          a default manifest
+        - the intermediate manifest that the linker will generate that should be
+          used to assert it doesn't add anything to the merged one.
+        - the list of all the manifest files to be merged by the manifest tool and
+          included into the link."""
+        generate_manifest = self._Setting(
+            ("VCLinkerTool", "GenerateManifest"), config, default="true"
+        )
+        if generate_manifest != "true":
+            # This means not only that the linker should not generate the intermediate
+            # manifest but also that the manifest tool should do nothing even when
+            # additional manifests are specified.
+            return ["/MANIFEST:NO"], [], []
+
+        output_name = name + ".intermediate.manifest"
+        flags = [
+            "/MANIFEST",
+            "/ManifestFile:" + output_name,
+        ]
+
+        # Instead of using the MANIFESTUAC flags, we generate a .manifest to
+        # include into the list of manifests. This allows us to avoid the need to
+        # do two passes during linking. The /MANIFEST flag and /ManifestFile are
+        # still used, and the intermediate manifest is used to assert that the
+        # final manifest we get from merging all the additional manifest files
+        # (plus the one we generate here) isn't modified by merging the
+        # intermediate into it.
+
+        # Always NO, because we generate a manifest file that has what we want.
+        flags.append("/MANIFESTUAC:NO")
+
+        config = self._TargetConfig(config)
+        enable_uac = self._Setting(
+            ("VCLinkerTool", "EnableUAC"), config, default="true"
+        )
+        manifest_files = []
+        generated_manifest_outer = (
+            "<?xml version='1.0' encoding='UTF-8' standalone='yes'?>"
+            "<assembly xmlns='urn:schemas-microsoft-com:asm.v1' manifestVersion='1.0'>"
+            "%s</assembly>"
+        )
+        if enable_uac == "true":
+            execution_level = self._Setting(
+                ("VCLinkerTool", "UACExecutionLevel"), config, default="0"
+            )
+            execution_level_map = {
+                "0": "asInvoker",
+                "1": "highestAvailable",
+                "2": "requireAdministrator",
+            }
+
+            ui_access = self._Setting(
+                ("VCLinkerTool", "UACUIAccess"), config, default="false"
+            )
+
+            inner = """
+<trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
+  <security>
+    <requestedPrivileges>
+      <requestedExecutionLevel level='{}' uiAccess='{}' />
+    </requestedPrivileges>
+  </security>
+</trustInfo>""".format(
+                execution_level_map[execution_level],
+                ui_access,
+            )
+        else:
+            inner = ""
+
+        generated_manifest_contents = generated_manifest_outer % inner
+        generated_name = name + ".generated.manifest"
+        # Need to join with the build_dir here as we're writing it during
+        # generation time, but we return the un-joined version because the build
+        # will occur in that directory. We only write the file if the contents
+        # have changed so that simply regenerating the project files doesn't
+        # cause a relink.
+        build_dir_generated_name = os.path.join(build_dir, generated_name)
+        gyp.common.EnsureDirExists(build_dir_generated_name)
+        f = gyp.common.WriteOnDiff(build_dir_generated_name)
+        f.write(generated_manifest_contents)
+        f.close()
+        manifest_files = [generated_name]
+
+        if allow_isolation:
+            flags.append("/ALLOWISOLATION")
+
+        manifest_files += self._GetAdditionalManifestFiles(config, gyp_to_build_path)
+        return flags, output_name, manifest_files
+
+    def _GetAdditionalManifestFiles(self, config, gyp_to_build_path):
+        """Gets additional manifest files that are added to the default one
+        generated by the linker."""
+        files = self._Setting(
+            ("VCManifestTool", "AdditionalManifestFiles"), config, default=[]
+        )
+        if isinstance(files, str):
+            files = files.split(";")
+        return [
+            os.path.normpath(gyp_to_build_path(self.ConvertVSMacros(f, config=config)))
+            for f in files
+        ]
+
+    def IsUseLibraryDependencyInputs(self, config):
+        """Returns whether the target should be linked via Use Library Dependency
+        Inputs (using component .objs of a given .lib)."""
+        config = self._TargetConfig(config)
+        uldi = self._Setting(("VCLinkerTool", "UseLibraryDependencyInputs"), config)
+        return uldi == "true"
+
+    def IsEmbedManifest(self, config):
+        """Returns whether manifest should be linked into binary."""
+        config = self._TargetConfig(config)
+        embed = self._Setting(
+            ("VCManifestTool", "EmbedManifest"), config, default="true"
+        )
+        return embed == "true"
+
+    def IsLinkIncremental(self, config):
+        """Returns whether the target should be linked incrementally."""
+        config = self._TargetConfig(config)
+        link_inc = self._Setting(("VCLinkerTool", "LinkIncremental"), config)
+        return link_inc != "1"
+
+    def GetRcflags(self, config, gyp_to_ninja_path):
+        """Returns the flags that need to be added to invocations of the resource
+        compiler."""
+        config = self._TargetConfig(config)
+        rcflags = []
+        rc = self._GetWrapper(
+            self, self.msvs_settings[config], "VCResourceCompilerTool", append=rcflags
+        )
+        rc("AdditionalIncludeDirectories", map=gyp_to_ninja_path, prefix="/I")
+        rcflags.append("/I" + gyp_to_ninja_path("."))
+        rc("PreprocessorDefinitions", prefix="/d")
+        # /l arg must be in hex without leading '0x'
+        rc("Culture", prefix="/l", map=lambda x: hex(int(x))[2:])
+        return rcflags
+
+    def BuildCygwinBashCommandLine(self, args, path_to_base):
+        """Build a command line that runs args via cygwin bash. We assume that all
+        incoming paths are in Windows normpath'd form, so they need to be
+        converted to posix style for the part of the command line that's passed to
+        bash. We also have to do some Visual Studio macro emulation here because
+        various rules use magic VS names for things. Also note that rules that
+        contain ninja variables cannot be fixed here (for example ${source}), so
+        the outer generator needs to make sure that the paths that are written out
+        are in posix style, if the command line will be used here."""
+        cygwin_dir = os.path.normpath(
+            os.path.join(path_to_base, self.msvs_cygwin_dirs[0])
+        )
+        cd = ("cd %s" % path_to_base).replace("\\", "/")
+        args = [a.replace("\\", "/").replace('"', '\\"') for a in args]
+        args = ["'%s'" % a.replace("'", "'\\''") for a in args]
+        bash_cmd = " ".join(args)
+        cmd = (
+            'call "%s\\setup_env.bat" && set CYGWIN=nontsec && ' % cygwin_dir
+            + f'bash -c "{cd} ; {bash_cmd}"'
+        )
+        return cmd
+
+    RuleShellFlags = collections.namedtuple("RuleShellFlags", ["cygwin", "quote"])
+
+    def GetRuleShellFlags(self, rule):
+        """Return RuleShellFlags about how the given rule should be run. This
+        includes whether it should run under cygwin (msvs_cygwin_shell), and
+        whether the commands should be quoted (msvs_quote_cmd)."""
+        # If the variable is unset, or set to 1 we use cygwin
+        cygwin = int(rule.get("msvs_cygwin_shell",
+                              self.spec.get("msvs_cygwin_shell", 1))) != 0
+        # Default to quoting. There's only a few special instances where the
+        # target command uses non-standard command line parsing and handle quotes
+        # and quote escaping differently.
+        quote_cmd = int(rule.get("msvs_quote_cmd", 1))
+        assert quote_cmd != 0 or cygwin != 1, \
+               "msvs_quote_cmd=0 only applicable for msvs_cygwin_shell=0"
+        return MsvsSettings.RuleShellFlags(cygwin, quote_cmd)
+
+    def _HasExplicitRuleForExtension(self, spec, extension):
+        """Determine if there's an explicit rule for a particular extension."""
+        for rule in spec.get("rules", []):
+            if rule["extension"] == extension:
+                return True
+        return False
+
+    def _HasExplicitIdlActions(self, spec):
+        """Determine if an action should not run midl for .idl files."""
+        return any(
+            [action.get("explicit_idl_action", 0) for action in spec.get("actions", [])]
+        )
+
+    def HasExplicitIdlRulesOrActions(self, spec):
+        """Determine if there's an explicit rule or action for idl files. When
+        there isn't we need to generate implicit rules to build MIDL .idl files."""
+        return self._HasExplicitRuleForExtension(
+            spec, "idl"
+        ) or self._HasExplicitIdlActions(spec)
+
+    def HasExplicitAsmRules(self, spec):
+        """Determine if there's an explicit rule for asm files. When there isn't we
+        need to generate implicit rules to assemble .asm files."""
+        return self._HasExplicitRuleForExtension(spec, "asm")
+
+    def GetIdlBuildData(self, source, config):
+        """Determine the implicit outputs for an idl file. Returns output
+        directory, outputs, and variables and flags that are required."""
+        config = self._TargetConfig(config)
+        midl_get = self._GetWrapper(self, self.msvs_settings[config], "VCMIDLTool")
+
+        def midl(name, default=None):
+            return self.ConvertVSMacros(midl_get(name, default=default), config=config)
+
+        tlb = midl("TypeLibraryName", default="${root}.tlb")
+        header = midl("HeaderFileName", default="${root}.h")
+        dlldata = midl("DLLDataFileName", default="dlldata.c")
+        iid = midl("InterfaceIdentifierFileName", default="${root}_i.c")
+        proxy = midl("ProxyFileName", default="${root}_p.c")
+        # Note that .tlb is not included in the outputs as it is not always
+        # generated depending on the content of the input idl file.
+        outdir = midl("OutputDirectory", default="")
+        output = [header, dlldata, iid, proxy]
+        variables = [
+            ("tlb", tlb),
+            ("h", header),
+            ("dlldata", dlldata),
+            ("iid", iid),
+            ("proxy", proxy),
+        ]
+        # TODO(scottmg): Are there configuration settings to set these flags?
+        target_platform = self.GetArch(config)
+        if target_platform == "x86":
+            target_platform = "win32"
+        flags = ["/char", "signed", "/env", target_platform, "/Oicf"]
+        return outdir, output, variables, flags
+
+
+def _LanguageMatchesForPch(source_ext, pch_source_ext):
+    c_exts = (".c",)
+    cc_exts = (".cc", ".cxx", ".cpp")
+    return (source_ext in c_exts and pch_source_ext in c_exts) or (
+        source_ext in cc_exts and pch_source_ext in cc_exts
+    )
+
+
+class PrecompiledHeader:
+    """Helper to generate dependencies and build rules to handle generation of
+    precompiled headers. Interface matches the GCH handler in xcode_emulation.py.
+    """
+
+    def __init__(
+        self, settings, config, gyp_to_build_path, gyp_to_unique_output, obj_ext
+    ):
+        self.settings = settings
+        self.config = config
+        pch_source = self.settings.msvs_precompiled_source[self.config]
+        self.pch_source = gyp_to_build_path(pch_source)
+        filename, _ = os.path.splitext(pch_source)
+        self.output_obj = gyp_to_unique_output(filename + obj_ext).lower()
+
+    def _PchHeader(self):
+        """Get the header that will appear in an #include line for all source
+        files."""
+        return self.settings.msvs_precompiled_header[self.config]
+
+    def GetObjDependencies(self, sources, objs, arch):
+        """Given a list of sources files and the corresponding object files,
+        returns a list of the pch files that should be depended upon. The
+        additional wrapping in the return value is for interface compatibility
+        with make.py on Mac, and xcode_emulation.py."""
+        assert arch is None
+        if not self._PchHeader():
+            return []
+        pch_ext = os.path.splitext(self.pch_source)[1]
+        for source in sources:
+            if _LanguageMatchesForPch(os.path.splitext(source)[1], pch_ext):
+                return [(None, None, self.output_obj)]
+        return []
+
+    def GetPchBuildCommands(self, arch):
+        """Not used on Windows as there are no additional build steps required
+        (instead, existing steps are modified in GetFlagsModifications below)."""
+        return []
+
+    def GetFlagsModifications(
+        self, input, output, implicit, command, cflags_c, cflags_cc, expand_special
+    ):
+        """Get the modified cflags and implicit dependencies that should be used
+        for the pch compilation step."""
+        if input == self.pch_source:
+            pch_output = ["/Yc" + self._PchHeader()]
+            if command == "cxx":
+                return (
+                    [("cflags_cc", map(expand_special, cflags_cc + pch_output))],
+                    self.output_obj,
+                    [],
+                )
+            elif command == "cc":
+                return (
+                    [("cflags_c", map(expand_special, cflags_c + pch_output))],
+                    self.output_obj,
+                    [],
+                )
+        return [], output, implicit
+
+
+vs_version = None
+
+
+def GetVSVersion(generator_flags):
+    global vs_version
+    if not vs_version:
+        vs_version = gyp.MSVSVersion.SelectVisualStudioVersion(
+            generator_flags.get("msvs_version", "auto"), allow_fallback=False
+        )
+    return vs_version
+
+
+def _GetVsvarsSetupArgs(generator_flags, arch):
+    vs = GetVSVersion(generator_flags)
+    return vs.SetupScript()
+
+
+def ExpandMacros(string, expansions):
+    """Expand $(Variable) per expansions dict. See MsvsSettings.GetVSMacroEnv
+    for the canonical way to retrieve a suitable dict."""
+    if "$" in string:
+        for old, new in expansions.items():
+            assert "$(" not in new, new
+            string = string.replace(old, new)
+    return string
+
+
+def _ExtractImportantEnvironment(output_of_set):
+    """Extracts environment variables required for the toolchain to run from
+    a textual dump output by the cmd.exe 'set' command."""
+    envvars_to_save = (
+        "goma_.*",  # TODO(scottmg): This is ugly, but needed for goma.
+        "include",
+        "lib",
+        "libpath",
+        "path",
+        "pathext",
+        "systemroot",
+        "temp",
+        "tmp",
+    )
+    env = {}
+    # This occasionally happens and leads to misleading SYSTEMROOT error messages
+    # if not caught here.
+    if output_of_set.count("=") == 0:
+        raise Exception("Invalid output_of_set. Value is:\n%s" % output_of_set)
+    for line in output_of_set.splitlines():
+        for envvar in envvars_to_save:
+            if re.match(envvar + "=", line.lower()):
+                var, setting = line.split("=", 1)
+                if envvar == "path":
+                    # Our own rules (for running gyp-win-tool) and other actions in
+                    # Chromium rely on python being in the path. Add the path to this
+                    # python here so that if it's not in the path when ninja is run
+                    # later, python will still be found.
+                    setting = os.path.dirname(sys.executable) + os.pathsep + setting
+                env[var.upper()] = setting
+                break
+    for required in ("SYSTEMROOT", "TEMP", "TMP"):
+        if required not in env:
+            raise Exception(
+                'Environment variable "%s" '
+                "required to be set to valid path" % required
+            )
+    return env
+
+
+def _FormatAsEnvironmentBlock(envvar_dict):
+    """Format as an 'environment block' directly suitable for CreateProcess.
+    Briefly this is a list of key=value\0, terminated by an additional \0. See
+    CreateProcess documentation for more details."""
+    block = ""
+    nul = "\0"
+    for key, value in envvar_dict.items():
+        block += key + "=" + value + nul
+    block += nul
+    return block
+
+
+def _ExtractCLPath(output_of_where):
+    """Gets the path to cl.exe based on the output of calling the environment
+    setup batch file, followed by the equivalent of `where`."""
+    # Take the first line, as that's the first found in the PATH.
+    for line in output_of_where.strip().splitlines():
+        if line.startswith("LOC:"):
+            return line[len("LOC:") :].strip()
+
+
+def GenerateEnvironmentFiles(
+    toplevel_build_dir, generator_flags, system_includes, open_out
+):
+    """It's not sufficient to have the absolute path to the compiler, linker,
+    etc. on Windows, as those tools rely on .dlls being in the PATH. We also
+    need to support both x86 and x64 compilers within the same build (to support
+    msvs_target_platform hackery). Different architectures require a different
+    compiler binary, and different supporting environment variables (INCLUDE,
+    LIB, LIBPATH). So, we extract the environment here, wrap all invocations
+    of compiler tools (cl, link, lib, rc, midl, etc.) via win_tool.py which
+    sets up the environment, and then we do not prefix the compiler with
+    an absolute path, instead preferring something like "cl.exe" in the rule
+    which will then run whichever the environment setup has put in the path.
+    When the following procedure to generate environment files does not
+    meet your requirement (e.g. for custom toolchains), you can pass
+    "-G ninja_use_custom_environment_files" to the gyp to suppress file
+    generation and use custom environment files prepared by yourself."""
+    archs = ("x86", "x64")
+    if generator_flags.get("ninja_use_custom_environment_files", 0):
+        cl_paths = {}
+        for arch in archs:
+            cl_paths[arch] = "cl.exe"
+        return cl_paths
+    vs = GetVSVersion(generator_flags)
+    cl_paths = {}
+    for arch in archs:
+        # Extract environment variables for subprocesses.
+        args = vs.SetupScript(arch)
+        args.extend(("&&", "set"))
+        popen = subprocess.Popen(
+            args, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT
+        )
+        variables = popen.communicate()[0].decode("utf-8")
+        if popen.returncode != 0:
+            raise Exception('"%s" failed with error %d' % (args, popen.returncode))
+        env = _ExtractImportantEnvironment(variables)
+
+        # Inject system includes from gyp files into INCLUDE.
+        if system_includes:
+            system_includes = system_includes | OrderedSet(
+                env.get("INCLUDE", "").split(";")
+            )
+            env["INCLUDE"] = ";".join(system_includes)
+
+        env_block = _FormatAsEnvironmentBlock(env)
+        f = open_out(os.path.join(toplevel_build_dir, "environment." + arch), "w")
+        f.write(env_block)
+        f.close()
+
+        # Find cl.exe location for this architecture.
+        args = vs.SetupScript(arch)
+        args.extend(
+            ("&&", "for", "%i", "in", "(cl.exe)", "do", "@echo", "LOC:%~$PATH:i")
+        )
+        popen = subprocess.Popen(args, shell=True, stdout=subprocess.PIPE)
+        output = popen.communicate()[0].decode("utf-8")
+        cl_paths[arch] = _ExtractCLPath(output)
+    return cl_paths
+
+
+def VerifyMissingSources(sources, build_dir, generator_flags, gyp_to_ninja):
+    """Emulate behavior of msvs_error_on_missing_sources present in the msvs
+    generator: Check that all regular source files, i.e. not created at run time,
+    exist on disk. Missing files cause needless recompilation when building via
+    VS, and we want this check to match for people/bots that build using ninja,
+    so they're not surprised when the VS build fails."""
+    if int(generator_flags.get("msvs_error_on_missing_sources", 0)):
+        no_specials = filter(lambda x: "$" not in x, sources)
+        relative = [os.path.join(build_dir, gyp_to_ninja(s)) for s in no_specials]
+        missing = [x for x in relative if not os.path.exists(x)]
+        if missing:
+            # They'll look like out\Release\..\..\stuff\things.cc, so normalize the
+            # path for a slightly less crazy looking output.
+            cleaned_up = [os.path.normpath(x) for x in missing]
+            raise Exception("Missing input files:\n%s" % "\n".join(cleaned_up))
+
+
+# Sets some values in default_variables, which are required for many
+# generators, run on Windows.
+def CalculateCommonVariables(default_variables, params):
+    generator_flags = params.get("generator_flags", {})
+
+    # Set a variable so conditions can be based on msvs_version.
+    msvs_version = gyp.msvs_emulation.GetVSVersion(generator_flags)
+    default_variables["MSVS_VERSION"] = msvs_version.ShortName()
+
+    # To determine processor word size on Windows, in addition to checking
+    # PROCESSOR_ARCHITECTURE (which reflects the word size of the current
+    # process), it is also necessary to check PROCESSOR_ARCHITEW6432 (which
+    # contains the actual word size of the system when running thru WOW64).
+    if "64" in os.environ.get("PROCESSOR_ARCHITECTURE", "") or "64" in os.environ.get(
+        "PROCESSOR_ARCHITEW6432", ""
+    ):
+        default_variables["MSVS_OS_BITS"] = 64
+    else:
+        default_variables["MSVS_OS_BITS"] = 32
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/ninja_syntax.py b/server/node_modules/node-gyp/gyp/pylib/gyp/ninja_syntax.py
new file mode 100644
index 0000000..0e3e86c
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/ninja_syntax.py
@@ -0,0 +1,174 @@
+# This file comes from
+#   https://github.com/martine/ninja/blob/master/misc/ninja_syntax.py
+# Do not edit!  Edit the upstream one instead.
+
+"""Python module for generating .ninja files.
+
+Note that this is emphatically not a required piece of Ninja; it's
+just a helpful utility for build-file-generation systems that already
+use Python.
+"""
+
+import textwrap
+
+
+def escape_path(word):
+    return word.replace("$ ", "$$ ").replace(" ", "$ ").replace(":", "$:")
+
+
+class Writer:
+    def __init__(self, output, width=78):
+        self.output = output
+        self.width = width
+
+    def newline(self):
+        self.output.write("\n")
+
+    def comment(self, text):
+        for line in textwrap.wrap(text, self.width - 2):
+            self.output.write("# " + line + "\n")
+
+    def variable(self, key, value, indent=0):
+        if value is None:
+            return
+        if isinstance(value, list):
+            value = " ".join(filter(None, value))  # Filter out empty strings.
+        self._line(f"{key} = {value}", indent)
+
+    def pool(self, name, depth):
+        self._line("pool %s" % name)
+        self.variable("depth", depth, indent=1)
+
+    def rule(
+        self,
+        name,
+        command,
+        description=None,
+        depfile=None,
+        generator=False,
+        pool=None,
+        restat=False,
+        rspfile=None,
+        rspfile_content=None,
+        deps=None,
+    ):
+        self._line("rule %s" % name)
+        self.variable("command", command, indent=1)
+        if description:
+            self.variable("description", description, indent=1)
+        if depfile:
+            self.variable("depfile", depfile, indent=1)
+        if generator:
+            self.variable("generator", "1", indent=1)
+        if pool:
+            self.variable("pool", pool, indent=1)
+        if restat:
+            self.variable("restat", "1", indent=1)
+        if rspfile:
+            self.variable("rspfile", rspfile, indent=1)
+        if rspfile_content:
+            self.variable("rspfile_content", rspfile_content, indent=1)
+        if deps:
+            self.variable("deps", deps, indent=1)
+
+    def build(
+        self, outputs, rule, inputs=None, implicit=None, order_only=None, variables=None
+    ):
+        outputs = self._as_list(outputs)
+        all_inputs = self._as_list(inputs)[:]
+        out_outputs = list(map(escape_path, outputs))
+        all_inputs = list(map(escape_path, all_inputs))
+
+        if implicit:
+            implicit = map(escape_path, self._as_list(implicit))
+            all_inputs.append("|")
+            all_inputs.extend(implicit)
+        if order_only:
+            order_only = map(escape_path, self._as_list(order_only))
+            all_inputs.append("||")
+            all_inputs.extend(order_only)
+
+        self._line(
+            "build {}: {}".format(" ".join(out_outputs), " ".join([rule] + all_inputs))
+        )
+
+        if variables:
+            if isinstance(variables, dict):
+                iterator = iter(variables.items())
+            else:
+                iterator = iter(variables)
+
+            for key, val in iterator:
+                self.variable(key, val, indent=1)
+
+        return outputs
+
+    def include(self, path):
+        self._line("include %s" % path)
+
+    def subninja(self, path):
+        self._line("subninja %s" % path)
+
+    def default(self, paths):
+        self._line("default %s" % " ".join(self._as_list(paths)))
+
+    def _count_dollars_before_index(self, s, i):
+        """Returns the number of '$' characters right in front of s[i]."""
+        dollar_count = 0
+        dollar_index = i - 1
+        while dollar_index > 0 and s[dollar_index] == "$":
+            dollar_count += 1
+            dollar_index -= 1
+        return dollar_count
+
+    def _line(self, text, indent=0):
+        """Write 'text' word-wrapped at self.width characters."""
+        leading_space = "  " * indent
+        while len(leading_space) + len(text) > self.width:
+            # The text is too wide; wrap if possible.
+
+            # Find the rightmost space that would obey our width constraint and
+            # that's not an escaped space.
+            available_space = self.width - len(leading_space) - len(" $")
+            space = available_space
+            while True:
+                space = text.rfind(" ", 0, space)
+                if space < 0 or self._count_dollars_before_index(text, space) % 2 == 0:
+                    break
+
+            if space < 0:
+                # No such space; just use the first unescaped space we can find.
+                space = available_space - 1
+                while True:
+                    space = text.find(" ", space + 1)
+                    if (
+                        space < 0
+                        or self._count_dollars_before_index(text, space) % 2 == 0
+                    ):
+                        break
+            if space < 0:
+                # Give up on breaking.
+                break
+
+            self.output.write(leading_space + text[0:space] + " $\n")
+            text = text[space + 1 :]
+
+            # Subsequent lines are continuations, so indent them.
+            leading_space = "  " * (indent + 2)
+
+        self.output.write(leading_space + text + "\n")
+
+    def _as_list(self, input):
+        if input is None:
+            return []
+        if isinstance(input, list):
+            return input
+        return [input]
+
+
+def escape(string):
+    """Escape a string such that it can be embedded into a Ninja file without
+    further interpretation."""
+    assert "\n" not in string, "Ninja syntax does not allow newlines"
+    # We only have one special metacharacter: '$'.
+    return string.replace("$", "$$")
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/simple_copy.py b/server/node_modules/node-gyp/gyp/pylib/gyp/simple_copy.py
new file mode 100644
index 0000000..729cec0
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/simple_copy.py
@@ -0,0 +1,61 @@
+# Copyright 2014 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""A clone of the default copy.deepcopy that doesn't handle cyclic
+structures or complex types except for dicts and lists. This is
+because gyp copies so large structure that small copy overhead ends up
+taking seconds in a project the size of Chromium."""
+
+
+class Error(Exception):
+    pass
+
+
+__all__ = ["Error", "deepcopy"]
+
+
+def deepcopy(x):
+    """Deep copy operation on gyp objects such as strings, ints, dicts
+  and lists. More than twice as fast as copy.deepcopy but much less
+  generic."""
+
+    try:
+        return _deepcopy_dispatch[type(x)](x)
+    except KeyError:
+        raise Error(
+            "Unsupported type %s for deepcopy. Use copy.deepcopy "
+            + "or expand simple_copy support." % type(x)
+        )
+
+
+_deepcopy_dispatch = d = {}
+
+
+def _deepcopy_atomic(x):
+    return x
+
+
+types = bool, float, int, str, type, type(None)
+
+for x in types:
+    d[x] = _deepcopy_atomic
+
+
+def _deepcopy_list(x):
+    return [deepcopy(a) for a in x]
+
+
+d[list] = _deepcopy_list
+
+
+def _deepcopy_dict(x):
+    y = {}
+    for key, value in x.items():
+        y[deepcopy(key)] = deepcopy(value)
+    return y
+
+
+d[dict] = _deepcopy_dict
+
+del d
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/win_tool.py b/server/node_modules/node-gyp/gyp/pylib/gyp/win_tool.py
new file mode 100755
index 0000000..638eee4
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/win_tool.py
@@ -0,0 +1,374 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Utility functions for Windows builds.
+
+These functions are executed via gyp-win-tool when using the ninja generator.
+"""
+
+
+import os
+import re
+import shutil
+import subprocess
+import stat
+import string
+import sys
+
+BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+
+# A regex matching an argument corresponding to the output filename passed to
+# link.exe.
+_LINK_EXE_OUT_ARG = re.compile("/OUT:(?P<out>.+)$", re.IGNORECASE)
+
+
+def main(args):
+    executor = WinTool()
+    exit_code = executor.Dispatch(args)
+    if exit_code is not None:
+        sys.exit(exit_code)
+
+
+class WinTool:
+    """This class performs all the Windows tooling steps. The methods can either
+  be executed directly, or dispatched from an argument list."""
+
+    def _UseSeparateMspdbsrv(self, env, args):
+        """Allows to use a unique instance of mspdbsrv.exe per linker instead of a
+    shared one."""
+        if len(args) < 1:
+            raise Exception("Not enough arguments")
+
+        if args[0] != "link.exe":
+            return
+
+        # Use the output filename passed to the linker to generate an endpoint name
+        # for mspdbsrv.exe.
+        endpoint_name = None
+        for arg in args:
+            m = _LINK_EXE_OUT_ARG.match(arg)
+            if m:
+                endpoint_name = re.sub(
+                    r"\W+", "", "%s_%d" % (m.group("out"), os.getpid())
+                )
+                break
+
+        if endpoint_name is None:
+            return
+
+        # Adds the appropriate environment variable. This will be read by link.exe
+        # to know which instance of mspdbsrv.exe it should connect to (if it's
+        # not set then the default endpoint is used).
+        env["_MSPDBSRV_ENDPOINT_"] = endpoint_name
+
+    def Dispatch(self, args):
+        """Dispatches a string command to a method."""
+        if len(args) < 1:
+            raise Exception("Not enough arguments")
+
+        method = "Exec%s" % self._CommandifyName(args[0])
+        return getattr(self, method)(*args[1:])
+
+    def _CommandifyName(self, name_string):
+        """Transforms a tool name like recursive-mirror to RecursiveMirror."""
+        return name_string.title().replace("-", "")
+
+    def _GetEnv(self, arch):
+        """Gets the saved environment from a file for a given architecture."""
+        # The environment is saved as an "environment block" (see CreateProcess
+        # and msvs_emulation for details). We convert to a dict here.
+        # Drop last 2 NULs, one for list terminator, one for trailing vs. separator.
+        pairs = open(arch).read()[:-2].split("\0")
+        kvs = [item.split("=", 1) for item in pairs]
+        return dict(kvs)
+
+    def ExecStamp(self, path):
+        """Simple stamp command."""
+        open(path, "w").close()
+
+    def ExecRecursiveMirror(self, source, dest):
+        """Emulation of rm -rf out && cp -af in out."""
+        if os.path.exists(dest):
+            if os.path.isdir(dest):
+
+                def _on_error(fn, path, excinfo):
+                    # The operation failed, possibly because the file is set to
+                    # read-only. If that's why, make it writable and try the op again.
+                    if not os.access(path, os.W_OK):
+                        os.chmod(path, stat.S_IWRITE)
+                    fn(path)
+
+                shutil.rmtree(dest, onerror=_on_error)
+            else:
+                if not os.access(dest, os.W_OK):
+                    # Attempt to make the file writable before deleting it.
+                    os.chmod(dest, stat.S_IWRITE)
+                os.unlink(dest)
+
+        if os.path.isdir(source):
+            shutil.copytree(source, dest)
+        else:
+            shutil.copy2(source, dest)
+
+    def ExecLinkWrapper(self, arch, use_separate_mspdbsrv, *args):
+        """Filter diagnostic output from link that looks like:
+    '   Creating library ui.dll.lib and object ui.dll.exp'
+    This happens when there are exports from the dll or exe.
+    """
+        env = self._GetEnv(arch)
+        if use_separate_mspdbsrv == "True":
+            self._UseSeparateMspdbsrv(env, args)
+        if sys.platform == "win32":
+            args = list(args)  # *args is a tuple by default, which is read-only.
+            args[0] = args[0].replace("/", "\\")
+        # https://docs.python.org/2/library/subprocess.html:
+        # "On Unix with shell=True [...] if args is a sequence, the first item
+        # specifies the command string, and any additional items will be treated as
+        # additional arguments to the shell itself.  That is to say, Popen does the
+        # equivalent of:
+        #   Popen(['/bin/sh', '-c', args[0], args[1], ...])"
+        # For that reason, since going through the shell doesn't seem necessary on
+        # non-Windows don't do that there.
+        link = subprocess.Popen(
+            args,
+            shell=sys.platform == "win32",
+            env=env,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.STDOUT,
+        )
+        out = link.communicate()[0].decode("utf-8")
+        for line in out.splitlines():
+            if (
+                not line.startswith("   Creating library ")
+                and not line.startswith("Generating code")
+                and not line.startswith("Finished generating code")
+            ):
+                print(line)
+        return link.returncode
+
+    def ExecLinkWithManifests(
+        self,
+        arch,
+        embed_manifest,
+        out,
+        ldcmd,
+        resname,
+        mt,
+        rc,
+        intermediate_manifest,
+        *manifests
+    ):
+        """A wrapper for handling creating a manifest resource and then executing
+    a link command."""
+        # The 'normal' way to do manifests is to have link generate a manifest
+        # based on gathering dependencies from the object files, then merge that
+        # manifest with other manifests supplied as sources, convert the merged
+        # manifest to a resource, and then *relink*, including the compiled
+        # version of the manifest resource. This breaks incremental linking, and
+        # is generally overly complicated. Instead, we merge all the manifests
+        # provided (along with one that includes what would normally be in the
+        # linker-generated one, see msvs_emulation.py), and include that into the
+        # first and only link. We still tell link to generate a manifest, but we
+        # only use that to assert that our simpler process did not miss anything.
+        variables = {
+            "python": sys.executable,
+            "arch": arch,
+            "out": out,
+            "ldcmd": ldcmd,
+            "resname": resname,
+            "mt": mt,
+            "rc": rc,
+            "intermediate_manifest": intermediate_manifest,
+            "manifests": " ".join(manifests),
+        }
+        add_to_ld = ""
+        if manifests:
+            subprocess.check_call(
+                "%(python)s gyp-win-tool manifest-wrapper %(arch)s %(mt)s -nologo "
+                "-manifest %(manifests)s -out:%(out)s.manifest" % variables
+            )
+            if embed_manifest == "True":
+                subprocess.check_call(
+                    "%(python)s gyp-win-tool manifest-to-rc %(arch)s %(out)s.manifest"
+                    " %(out)s.manifest.rc %(resname)s" % variables
+                )
+                subprocess.check_call(
+                    "%(python)s gyp-win-tool rc-wrapper %(arch)s %(rc)s "
+                    "%(out)s.manifest.rc" % variables
+                )
+                add_to_ld = " %(out)s.manifest.res" % variables
+        subprocess.check_call(ldcmd + add_to_ld)
+
+        # Run mt.exe on the theoretically complete manifest we generated, merging
+        # it with the one the linker generated to confirm that the linker
+        # generated one does not add anything. This is strictly unnecessary for
+        # correctness, it's only to verify that e.g. /MANIFESTDEPENDENCY was not
+        # used in a #pragma comment.
+        if manifests:
+            # Merge the intermediate one with ours to .assert.manifest, then check
+            # that .assert.manifest is identical to ours.
+            subprocess.check_call(
+                "%(python)s gyp-win-tool manifest-wrapper %(arch)s %(mt)s -nologo "
+                "-manifest %(out)s.manifest %(intermediate_manifest)s "
+                "-out:%(out)s.assert.manifest" % variables
+            )
+            assert_manifest = "%(out)s.assert.manifest" % variables
+            our_manifest = "%(out)s.manifest" % variables
+            # Load and normalize the manifests. mt.exe sometimes removes whitespace,
+            # and sometimes doesn't unfortunately.
+            with open(our_manifest) as our_f:
+                with open(assert_manifest) as assert_f:
+                    translator = str.maketrans('', '', string.whitespace)
+                    our_data = our_f.read().translate(translator)
+                    assert_data = assert_f.read().translate(translator)
+            if our_data != assert_data:
+                os.unlink(out)
+
+                def dump(filename):
+                    print(filename, file=sys.stderr)
+                    print("-----", file=sys.stderr)
+                    with open(filename) as f:
+                        print(f.read(), file=sys.stderr)
+                        print("-----", file=sys.stderr)
+
+                dump(intermediate_manifest)
+                dump(our_manifest)
+                dump(assert_manifest)
+                sys.stderr.write(
+                    'Linker generated manifest "%s" added to final manifest "%s" '
+                    '(result in "%s"). '
+                    "Were /MANIFEST switches used in #pragma statements? "
+                    % (intermediate_manifest, our_manifest, assert_manifest)
+                )
+                return 1
+
+    def ExecManifestWrapper(self, arch, *args):
+        """Run manifest tool with environment set. Strip out undesirable warning
+    (some XML blocks are recognized by the OS loader, but not the manifest
+    tool)."""
+        env = self._GetEnv(arch)
+        popen = subprocess.Popen(
+            args, shell=True, env=env, stdout=subprocess.PIPE, stderr=subprocess.STDOUT
+        )
+        out = popen.communicate()[0].decode("utf-8")
+        for line in out.splitlines():
+            if line and "manifest authoring warning 81010002" not in line:
+                print(line)
+        return popen.returncode
+
+    def ExecManifestToRc(self, arch, *args):
+        """Creates a resource file pointing a SxS assembly manifest.
+    |args| is tuple containing path to resource file, path to manifest file
+    and resource name which can be "1" (for executables) or "2" (for DLLs)."""
+        manifest_path, resource_path, resource_name = args
+        with open(resource_path, "w") as output:
+            output.write(
+                '#include <windows.h>\n%s RT_MANIFEST "%s"'
+                % (resource_name, os.path.abspath(manifest_path).replace("\\", "/"))
+            )
+
+    def ExecMidlWrapper(self, arch, outdir, tlb, h, dlldata, iid, proxy, idl, *flags):
+        """Filter noisy filenames output from MIDL compile step that isn't
+    quietable via command line flags.
+    """
+        args = (
+            ["midl", "/nologo"]
+            + list(flags)
+            + [
+                "/out",
+                outdir,
+                "/tlb",
+                tlb,
+                "/h",
+                h,
+                "/dlldata",
+                dlldata,
+                "/iid",
+                iid,
+                "/proxy",
+                proxy,
+                idl,
+            ]
+        )
+        env = self._GetEnv(arch)
+        popen = subprocess.Popen(
+            args, shell=True, env=env, stdout=subprocess.PIPE, stderr=subprocess.STDOUT
+        )
+        out = popen.communicate()[0].decode("utf-8")
+        # Filter junk out of stdout, and write filtered versions. Output we want
+        # to filter is pairs of lines that look like this:
+        # Processing C:\Program Files (x86)\Microsoft SDKs\...\include\objidl.idl
+        # objidl.idl
+        lines = out.splitlines()
+        prefixes = ("Processing ", "64 bit Processing ")
+        processing = {os.path.basename(x) for x in lines if x.startswith(prefixes)}
+        for line in lines:
+            if not line.startswith(prefixes) and line not in processing:
+                print(line)
+        return popen.returncode
+
+    def ExecAsmWrapper(self, arch, *args):
+        """Filter logo banner from invocations of asm.exe."""
+        env = self._GetEnv(arch)
+        popen = subprocess.Popen(
+            args, shell=True, env=env, stdout=subprocess.PIPE, stderr=subprocess.STDOUT
+        )
+        out = popen.communicate()[0].decode("utf-8")
+        for line in out.splitlines():
+            if (
+                not line.startswith("Copyright (C) Microsoft Corporation")
+                and not line.startswith("Microsoft (R) Macro Assembler")
+                and not line.startswith(" Assembling: ")
+                and line
+            ):
+                print(line)
+        return popen.returncode
+
+    def ExecRcWrapper(self, arch, *args):
+        """Filter logo banner from invocations of rc.exe. Older versions of RC
+    don't support the /nologo flag."""
+        env = self._GetEnv(arch)
+        popen = subprocess.Popen(
+            args, shell=True, env=env, stdout=subprocess.PIPE, stderr=subprocess.STDOUT
+        )
+        out = popen.communicate()[0].decode("utf-8")
+        for line in out.splitlines():
+            if (
+                not line.startswith("Microsoft (R) Windows (R) Resource Compiler")
+                and not line.startswith("Copyright (C) Microsoft Corporation")
+                and line
+            ):
+                print(line)
+        return popen.returncode
+
+    def ExecActionWrapper(self, arch, rspfile, *dir):
+        """Runs an action command line from a response file using the environment
+    for |arch|. If |dir| is supplied, use that as the working directory."""
+        env = self._GetEnv(arch)
+        # TODO(scottmg): This is a temporary hack to get some specific variables
+        # through to actions that are set after gyp-time. http://crbug.com/333738.
+        for k, v in os.environ.items():
+            if k not in env:
+                env[k] = v
+        args = open(rspfile).read()
+        dir = dir[0] if dir else None
+        return subprocess.call(args, shell=True, env=env, cwd=dir)
+
+    def ExecClCompile(self, project_dir, selected_files):
+        """Executed by msvs-ninja projects when the 'ClCompile' target is used to
+    build selected C/C++ files."""
+        project_dir = os.path.relpath(project_dir, BASE_DIR)
+        selected_files = selected_files.split(";")
+        ninja_targets = [
+            os.path.join(project_dir, filename) + "^^" for filename in selected_files
+        ]
+        cmd = ["ninja.exe"]
+        cmd.extend(ninja_targets)
+        return subprocess.call(cmd, shell=True, cwd=BASE_DIR)
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/xcode_emulation.py b/server/node_modules/node-gyp/gyp/pylib/gyp/xcode_emulation.py
new file mode 100644
index 0000000..a75d8ee
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/xcode_emulation.py
@@ -0,0 +1,1939 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+This module contains classes that help to emulate xcodebuild behavior on top of
+other build systems, such as make and ninja.
+"""
+
+
+import copy
+import gyp.common
+import os
+import os.path
+import re
+import shlex
+import subprocess
+import sys
+from gyp.common import GypError
+
+# Populated lazily by XcodeVersion, for efficiency, and to fix an issue when
+# "xcodebuild" is called too quickly (it has been found to return incorrect
+# version number).
+XCODE_VERSION_CACHE = None
+
+# Populated lazily by GetXcodeArchsDefault, to an |XcodeArchsDefault| instance
+# corresponding to the installed version of Xcode.
+XCODE_ARCHS_DEFAULT_CACHE = None
+
+
+def XcodeArchsVariableMapping(archs, archs_including_64_bit=None):
+    """Constructs a dictionary with expansion for $(ARCHS_STANDARD) variable,
+  and optionally for $(ARCHS_STANDARD_INCLUDING_64_BIT)."""
+    mapping = {"$(ARCHS_STANDARD)": archs}
+    if archs_including_64_bit:
+        mapping["$(ARCHS_STANDARD_INCLUDING_64_BIT)"] = archs_including_64_bit
+    return mapping
+
+
+class XcodeArchsDefault:
+    """A class to resolve ARCHS variable from xcode_settings, resolving Xcode
+  macros and implementing filtering by VALID_ARCHS. The expansion of macros
+  depends on the SDKROOT used ("macosx", "iphoneos", "iphonesimulator") and
+  on the version of Xcode.
+  """
+
+    # Match variable like $(ARCHS_STANDARD).
+    variable_pattern = re.compile(r"\$$[a-zA-Z_][a-zA-Z0-9_]*$$")
+
+    def __init__(self, default, mac, iphonesimulator, iphoneos):
+        self._default = (default,)
+        self._archs = {"mac": mac, "ios": iphoneos, "iossim": iphonesimulator}
+
+    def _VariableMapping(self, sdkroot):
+        """Returns the dictionary of variable mapping depending on the SDKROOT."""
+        sdkroot = sdkroot.lower()
+        if "iphoneos" in sdkroot:
+            return self._archs["ios"]
+        elif "iphonesimulator" in sdkroot:
+            return self._archs["iossim"]
+        else:
+            return self._archs["mac"]
+
+    def _ExpandArchs(self, archs, sdkroot):
+        """Expands variables references in ARCHS, and remove duplicates."""
+        variable_mapping = self._VariableMapping(sdkroot)
+        expanded_archs = []
+        for arch in archs:
+            if self.variable_pattern.match(arch):
+                variable = arch
+                try:
+                    variable_expansion = variable_mapping[variable]
+                    for arch in variable_expansion:
+                        if arch not in expanded_archs:
+                            expanded_archs.append(arch)
+                except KeyError:
+                    print('Warning: Ignoring unsupported variable "%s".' % variable)
+            elif arch not in expanded_archs:
+                expanded_archs.append(arch)
+        return expanded_archs
+
+    def ActiveArchs(self, archs, valid_archs, sdkroot):
+        """Expands variables references in ARCHS, and filter by VALID_ARCHS if it
+    is defined (if not set, Xcode accept any value in ARCHS, otherwise, only
+    values present in VALID_ARCHS are kept)."""
+        expanded_archs = self._ExpandArchs(archs or self._default, sdkroot or "")
+        if valid_archs:
+            filtered_archs = []
+            for arch in expanded_archs:
+                if arch in valid_archs:
+                    filtered_archs.append(arch)
+            expanded_archs = filtered_archs
+        return expanded_archs
+
+
+def GetXcodeArchsDefault():
+    """Returns the |XcodeArchsDefault| object to use to expand ARCHS for the
+  installed version of Xcode. The default values used by Xcode for ARCHS
+  and the expansion of the variables depends on the version of Xcode used.
+
+  For all version anterior to Xcode 5.0 or posterior to Xcode 5.1 included
+  uses $(ARCHS_STANDARD) if ARCHS is unset, while Xcode 5.0 to 5.0.2 uses
+  $(ARCHS_STANDARD_INCLUDING_64_BIT). This variable was added to Xcode 5.0
+  and deprecated with Xcode 5.1.
+
+  For "macosx" SDKROOT, all version starting with Xcode 5.0 includes 64-bit
+  architecture as part of $(ARCHS_STANDARD) and default to only building it.
+
+  For "iphoneos" and "iphonesimulator" SDKROOT, 64-bit architectures are part
+  of $(ARCHS_STANDARD_INCLUDING_64_BIT) from Xcode 5.0. From Xcode 5.1, they
+  are also part of $(ARCHS_STANDARD).
+
+  All these rules are coded in the construction of the |XcodeArchsDefault|
+  object to use depending on the version of Xcode detected. The object is
+  for performance reason."""
+    global XCODE_ARCHS_DEFAULT_CACHE
+    if XCODE_ARCHS_DEFAULT_CACHE:
+        return XCODE_ARCHS_DEFAULT_CACHE
+    xcode_version, _ = XcodeVersion()
+    if xcode_version < "0500":
+        XCODE_ARCHS_DEFAULT_CACHE = XcodeArchsDefault(
+            "$(ARCHS_STANDARD)",
+            XcodeArchsVariableMapping(["i386"]),
+            XcodeArchsVariableMapping(["i386"]),
+            XcodeArchsVariableMapping(["armv7"]),
+        )
+    elif xcode_version < "0510":
+        XCODE_ARCHS_DEFAULT_CACHE = XcodeArchsDefault(
+            "$(ARCHS_STANDARD_INCLUDING_64_BIT)",
+            XcodeArchsVariableMapping(["x86_64"], ["x86_64"]),
+            XcodeArchsVariableMapping(["i386"], ["i386", "x86_64"]),
+            XcodeArchsVariableMapping(
+                ["armv7", "armv7s"], ["armv7", "armv7s", "arm64"]
+            ),
+        )
+    else:
+        XCODE_ARCHS_DEFAULT_CACHE = XcodeArchsDefault(
+            "$(ARCHS_STANDARD)",
+            XcodeArchsVariableMapping(["x86_64"], ["x86_64"]),
+            XcodeArchsVariableMapping(["i386", "x86_64"], ["i386", "x86_64"]),
+            XcodeArchsVariableMapping(
+                ["armv7", "armv7s", "arm64"], ["armv7", "armv7s", "arm64"]
+            ),
+        )
+    return XCODE_ARCHS_DEFAULT_CACHE
+
+
+class XcodeSettings:
+    """A class that understands the gyp 'xcode_settings' object."""
+
+    # Populated lazily by _SdkPath(). Shared by all XcodeSettings, so cached
+    # at class-level for efficiency.
+    _sdk_path_cache = {}
+    _platform_path_cache = {}
+    _sdk_root_cache = {}
+
+    # Populated lazily by GetExtraPlistItems(). Shared by all XcodeSettings, so
+    # cached at class-level for efficiency.
+    _plist_cache = {}
+
+    # Populated lazily by GetIOSPostbuilds.  Shared by all XcodeSettings, so
+    # cached at class-level for efficiency.
+    _codesigning_key_cache = {}
+
+    def __init__(self, spec):
+        self.spec = spec
+
+        self.isIOS = False
+        self.mac_toolchain_dir = None
+        self.header_map_path = None
+
+        # Per-target 'xcode_settings' are pushed down into configs earlier by gyp.
+        # This means self.xcode_settings[config] always contains all settings
+        # for that config -- the per-target settings as well. Settings that are
+        # the same for all configs are implicitly per-target settings.
+        self.xcode_settings = {}
+        configs = spec["configurations"]
+        for configname, config in configs.items():
+            self.xcode_settings[configname] = config.get("xcode_settings", {})
+            self._ConvertConditionalKeys(configname)
+            if self.xcode_settings[configname].get("IPHONEOS_DEPLOYMENT_TARGET", None):
+                self.isIOS = True
+
+        # This is only non-None temporarily during the execution of some methods.
+        self.configname = None
+
+        # Used by _AdjustLibrary to match .a and .dylib entries in libraries.
+        self.library_re = re.compile(r"^lib([^/]+)\.(a|dylib)$")
+
+    def _ConvertConditionalKeys(self, configname):
+        """Converts or warns on conditional keys.  Xcode supports conditional keys,
+    such as CODE_SIGN_IDENTITY[sdk=iphoneos*].  This is a partial implementation
+    with some keys converted while the rest force a warning."""
+        settings = self.xcode_settings[configname]
+        conditional_keys = [key for key in settings if key.endswith("]")]
+        for key in conditional_keys:
+            # If you need more, speak up at http://crbug.com/122592
+            if key.endswith("[sdk=iphoneos*]"):
+                if configname.endswith("iphoneos"):
+                    new_key = key.split("[")[0]
+                    settings[new_key] = settings[key]
+            else:
+                print(
+                    "Warning: Conditional keys not implemented, ignoring:",
+                    " ".join(conditional_keys),
+                )
+            del settings[key]
+
+    def _Settings(self):
+        assert self.configname
+        return self.xcode_settings[self.configname]
+
+    def _Test(self, test_key, cond_key, default):
+        return self._Settings().get(test_key, default) == cond_key
+
+    def _Appendf(self, lst, test_key, format_str, default=None):
+        if test_key in self._Settings():
+            lst.append(format_str % str(self._Settings()[test_key]))
+        elif default:
+            lst.append(format_str % str(default))
+
+    def _WarnUnimplemented(self, test_key):
+        if test_key in self._Settings():
+            print('Warning: Ignoring not yet implemented key "%s".' % test_key)
+
+    def IsBinaryOutputFormat(self, configname):
+        default = "binary" if self.isIOS else "xml"
+        format = self.xcode_settings[configname].get("INFOPLIST_OUTPUT_FORMAT", default)
+        return format == "binary"
+
+    def IsIosFramework(self):
+        return self.spec["type"] == "shared_library" and self._IsBundle() and self.isIOS
+
+    def _IsBundle(self):
+        return (
+            int(self.spec.get("mac_bundle", 0)) != 0
+            or self._IsXCTest()
+            or self._IsXCUiTest()
+        )
+
+    def _IsXCTest(self):
+        return int(self.spec.get("mac_xctest_bundle", 0)) != 0
+
+    def _IsXCUiTest(self):
+        return int(self.spec.get("mac_xcuitest_bundle", 0)) != 0
+
+    def _IsIosAppExtension(self):
+        return int(self.spec.get("ios_app_extension", 0)) != 0
+
+    def _IsIosWatchKitExtension(self):
+        return int(self.spec.get("ios_watchkit_extension", 0)) != 0
+
+    def _IsIosWatchApp(self):
+        return int(self.spec.get("ios_watch_app", 0)) != 0
+
+    def GetFrameworkVersion(self):
+        """Returns the framework version of the current target. Only valid for
+    bundles."""
+        assert self._IsBundle()
+        return self.GetPerTargetSetting("FRAMEWORK_VERSION", default="A")
+
+    def GetWrapperExtension(self):
+        """Returns the bundle extension (.app, .framework, .plugin, etc).  Only
+    valid for bundles."""
+        assert self._IsBundle()
+        if self.spec["type"] in ("loadable_module", "shared_library"):
+            default_wrapper_extension = {
+                "loadable_module": "bundle",
+                "shared_library": "framework",
+            }[self.spec["type"]]
+            wrapper_extension = self.GetPerTargetSetting(
+                "WRAPPER_EXTENSION", default=default_wrapper_extension
+            )
+            return "." + self.spec.get("product_extension", wrapper_extension)
+        elif self.spec["type"] == "executable":
+            if self._IsIosAppExtension() or self._IsIosWatchKitExtension():
+                return "." + self.spec.get("product_extension", "appex")
+            else:
+                return "." + self.spec.get("product_extension", "app")
+        else:
+            assert False, "Don't know extension for '{}', target '{}'".format(
+                self.spec["type"],
+                self.spec["target_name"],
+            )
+
+    def GetProductName(self):
+        """Returns PRODUCT_NAME."""
+        return self.spec.get("product_name", self.spec["target_name"])
+
+    def GetFullProductName(self):
+        """Returns FULL_PRODUCT_NAME."""
+        if self._IsBundle():
+            return self.GetWrapperName()
+        else:
+            return self._GetStandaloneBinaryPath()
+
+    def GetWrapperName(self):
+        """Returns the directory name of the bundle represented by this target.
+    Only valid for bundles."""
+        assert self._IsBundle()
+        return self.GetProductName() + self.GetWrapperExtension()
+
+    def GetBundleContentsFolderPath(self):
+        """Returns the qualified path to the bundle's contents folder. E.g.
+    Chromium.app/Contents or Foo.bundle/Versions/A. Only valid for bundles."""
+        if self.isIOS:
+            return self.GetWrapperName()
+        assert self._IsBundle()
+        if self.spec["type"] == "shared_library":
+            return os.path.join(
+                self.GetWrapperName(), "Versions", self.GetFrameworkVersion()
+            )
+        else:
+            # loadable_modules have a 'Contents' folder like executables.
+            return os.path.join(self.GetWrapperName(), "Contents")
+
+    def GetBundleResourceFolder(self):
+        """Returns the qualified path to the bundle's resource folder. E.g.
+    Chromium.app/Contents/Resources. Only valid for bundles."""
+        assert self._IsBundle()
+        if self.isIOS:
+            return self.GetBundleContentsFolderPath()
+        return os.path.join(self.GetBundleContentsFolderPath(), "Resources")
+
+    def GetBundleExecutableFolderPath(self):
+        """Returns the qualified path to the bundle's executables folder. E.g.
+    Chromium.app/Contents/MacOS. Only valid for bundles."""
+        assert self._IsBundle()
+        if self.spec["type"] in ("shared_library") or self.isIOS:
+            return self.GetBundleContentsFolderPath()
+        elif self.spec["type"] in ("executable", "loadable_module"):
+            return os.path.join(self.GetBundleContentsFolderPath(), "MacOS")
+
+    def GetBundleJavaFolderPath(self):
+        """Returns the qualified path to the bundle's Java resource folder.
+    E.g. Chromium.app/Contents/Resources/Java. Only valid for bundles."""
+        assert self._IsBundle()
+        return os.path.join(self.GetBundleResourceFolder(), "Java")
+
+    def GetBundleFrameworksFolderPath(self):
+        """Returns the qualified path to the bundle's frameworks folder. E.g,
+    Chromium.app/Contents/Frameworks. Only valid for bundles."""
+        assert self._IsBundle()
+        return os.path.join(self.GetBundleContentsFolderPath(), "Frameworks")
+
+    def GetBundleSharedFrameworksFolderPath(self):
+        """Returns the qualified path to the bundle's frameworks folder. E.g,
+    Chromium.app/Contents/SharedFrameworks. Only valid for bundles."""
+        assert self._IsBundle()
+        return os.path.join(self.GetBundleContentsFolderPath(), "SharedFrameworks")
+
+    def GetBundleSharedSupportFolderPath(self):
+        """Returns the qualified path to the bundle's shared support folder. E.g,
+    Chromium.app/Contents/SharedSupport. Only valid for bundles."""
+        assert self._IsBundle()
+        if self.spec["type"] == "shared_library":
+            return self.GetBundleResourceFolder()
+        else:
+            return os.path.join(self.GetBundleContentsFolderPath(), "SharedSupport")
+
+    def GetBundlePlugInsFolderPath(self):
+        """Returns the qualified path to the bundle's plugins folder. E.g,
+    Chromium.app/Contents/PlugIns. Only valid for bundles."""
+        assert self._IsBundle()
+        return os.path.join(self.GetBundleContentsFolderPath(), "PlugIns")
+
+    def GetBundleXPCServicesFolderPath(self):
+        """Returns the qualified path to the bundle's XPC services folder. E.g,
+    Chromium.app/Contents/XPCServices. Only valid for bundles."""
+        assert self._IsBundle()
+        return os.path.join(self.GetBundleContentsFolderPath(), "XPCServices")
+
+    def GetBundlePlistPath(self):
+        """Returns the qualified path to the bundle's plist file. E.g.
+    Chromium.app/Contents/Info.plist. Only valid for bundles."""
+        assert self._IsBundle()
+        if (
+            self.spec["type"] in ("executable", "loadable_module")
+            or self.IsIosFramework()
+        ):
+            return os.path.join(self.GetBundleContentsFolderPath(), "Info.plist")
+        else:
+            return os.path.join(
+                self.GetBundleContentsFolderPath(), "Resources", "Info.plist"
+            )
+
+    def GetProductType(self):
+        """Returns the PRODUCT_TYPE of this target."""
+        if self._IsIosAppExtension():
+            assert self._IsBundle(), (
+                "ios_app_extension flag requires mac_bundle "
+                "(target %s)" % self.spec["target_name"]
+            )
+            return "com.apple.product-type.app-extension"
+        if self._IsIosWatchKitExtension():
+            assert self._IsBundle(), (
+                "ios_watchkit_extension flag requires "
+                "mac_bundle (target %s)" % self.spec["target_name"]
+            )
+            return "com.apple.product-type.watchkit-extension"
+        if self._IsIosWatchApp():
+            assert self._IsBundle(), (
+                "ios_watch_app flag requires mac_bundle "
+                "(target %s)" % self.spec["target_name"]
+            )
+            return "com.apple.product-type.application.watchapp"
+        if self._IsXCUiTest():
+            assert self._IsBundle(), (
+                "mac_xcuitest_bundle flag requires mac_bundle "
+                "(target %s)" % self.spec["target_name"]
+            )
+            return "com.apple.product-type.bundle.ui-testing"
+        if self._IsBundle():
+            return {
+                "executable": "com.apple.product-type.application",
+                "loadable_module": "com.apple.product-type.bundle",
+                "shared_library": "com.apple.product-type.framework",
+            }[self.spec["type"]]
+        else:
+            return {
+                "executable": "com.apple.product-type.tool",
+                "loadable_module": "com.apple.product-type.library.dynamic",
+                "shared_library": "com.apple.product-type.library.dynamic",
+                "static_library": "com.apple.product-type.library.static",
+            }[self.spec["type"]]
+
+    def GetMachOType(self):
+        """Returns the MACH_O_TYPE of this target."""
+        # Weird, but matches Xcode.
+        if not self._IsBundle() and self.spec["type"] == "executable":
+            return ""
+        return {
+            "executable": "mh_execute",
+            "static_library": "staticlib",
+            "shared_library": "mh_dylib",
+            "loadable_module": "mh_bundle",
+        }[self.spec["type"]]
+
+    def _GetBundleBinaryPath(self):
+        """Returns the name of the bundle binary of by this target.
+    E.g. Chromium.app/Contents/MacOS/Chromium. Only valid for bundles."""
+        assert self._IsBundle()
+        return os.path.join(
+            self.GetBundleExecutableFolderPath(), self.GetExecutableName()
+        )
+
+    def _GetStandaloneExecutableSuffix(self):
+        if "product_extension" in self.spec:
+            return "." + self.spec["product_extension"]
+        return {
+            "executable": "",
+            "static_library": ".a",
+            "shared_library": ".dylib",
+            "loadable_module": ".so",
+        }[self.spec["type"]]
+
+    def _GetStandaloneExecutablePrefix(self):
+        return self.spec.get(
+            "product_prefix",
+            {
+                "executable": "",
+                "static_library": "lib",
+                "shared_library": "lib",
+                # Non-bundled loadable_modules are called foo.so for some reason
+                # (that is, .so and no prefix) with the xcode build -- match that.
+                "loadable_module": "",
+            }[self.spec["type"]],
+        )
+
+    def _GetStandaloneBinaryPath(self):
+        """Returns the name of the non-bundle binary represented by this target.
+    E.g. hello_world. Only valid for non-bundles."""
+        assert not self._IsBundle()
+        assert self.spec["type"] in (
+            "executable",
+            "shared_library",
+            "static_library",
+            "loadable_module",
+        ), ("Unexpected type %s" % self.spec["type"])
+        target = self.spec["target_name"]
+        if self.spec["type"] == "static_library":
+            if target[:3] == "lib":
+                target = target[3:]
+        elif self.spec["type"] in ("loadable_module", "shared_library"):
+            if target[:3] == "lib":
+                target = target[3:]
+
+        target_prefix = self._GetStandaloneExecutablePrefix()
+        target = self.spec.get("product_name", target)
+        target_ext = self._GetStandaloneExecutableSuffix()
+        return target_prefix + target + target_ext
+
+    def GetExecutableName(self):
+        """Returns the executable name of the bundle represented by this target.
+    E.g. Chromium."""
+        if self._IsBundle():
+            return self.spec.get("product_name", self.spec["target_name"])
+        else:
+            return self._GetStandaloneBinaryPath()
+
+    def GetExecutablePath(self):
+        """Returns the qualified path to the primary executable of the bundle
+    represented by this target. E.g. Chromium.app/Contents/MacOS/Chromium."""
+        if self._IsBundle():
+            return self._GetBundleBinaryPath()
+        else:
+            return self._GetStandaloneBinaryPath()
+
+    def GetActiveArchs(self, configname):
+        """Returns the architectures this target should be built for."""
+        config_settings = self.xcode_settings[configname]
+        xcode_archs_default = GetXcodeArchsDefault()
+        return xcode_archs_default.ActiveArchs(
+            config_settings.get("ARCHS"),
+            config_settings.get("VALID_ARCHS"),
+            config_settings.get("SDKROOT"),
+        )
+
+    def _GetSdkVersionInfoItem(self, sdk, infoitem):
+        # xcodebuild requires Xcode and can't run on Command Line Tools-only
+        # systems from 10.7 onward.
+        # Since the CLT has no SDK paths anyway, returning None is the
+        # most sensible route and should still do the right thing.
+        try:
+            return GetStdoutQuiet(["xcrun", "--sdk", sdk, infoitem])
+        except GypError:
+            pass
+
+    def _SdkRoot(self, configname):
+        if configname is None:
+            configname = self.configname
+        return self.GetPerConfigSetting("SDKROOT", configname, default="")
+
+    def _XcodePlatformPath(self, configname=None):
+        sdk_root = self._SdkRoot(configname)
+        if sdk_root not in XcodeSettings._platform_path_cache:
+            platform_path = self._GetSdkVersionInfoItem(
+                sdk_root, "--show-sdk-platform-path"
+            )
+            XcodeSettings._platform_path_cache[sdk_root] = platform_path
+        return XcodeSettings._platform_path_cache[sdk_root]
+
+    def _SdkPath(self, configname=None):
+        sdk_root = self._SdkRoot(configname)
+        if sdk_root.startswith("/"):
+            return sdk_root
+        return self._XcodeSdkPath(sdk_root)
+
+    def _XcodeSdkPath(self, sdk_root):
+        if sdk_root not in XcodeSettings._sdk_path_cache:
+            sdk_path = self._GetSdkVersionInfoItem(sdk_root, "--show-sdk-path")
+            XcodeSettings._sdk_path_cache[sdk_root] = sdk_path
+            if sdk_root:
+                XcodeSettings._sdk_root_cache[sdk_path] = sdk_root
+        return XcodeSettings._sdk_path_cache[sdk_root]
+
+    def _AppendPlatformVersionMinFlags(self, lst):
+        self._Appendf(lst, "MACOSX_DEPLOYMENT_TARGET", "-mmacosx-version-min=%s")
+        if "IPHONEOS_DEPLOYMENT_TARGET" in self._Settings():
+            # TODO: Implement this better?
+            sdk_path_basename = os.path.basename(self._SdkPath())
+            if sdk_path_basename.lower().startswith("iphonesimulator"):
+                self._Appendf(
+                    lst, "IPHONEOS_DEPLOYMENT_TARGET", "-mios-simulator-version-min=%s"
+                )
+            else:
+                self._Appendf(
+                    lst, "IPHONEOS_DEPLOYMENT_TARGET", "-miphoneos-version-min=%s"
+                )
+
+    def GetCflags(self, configname, arch=None):
+        """Returns flags that need to be added to .c, .cc, .m, and .mm
+    compilations."""
+        # This functions (and the similar ones below) do not offer complete
+        # emulation of all xcode_settings keys. They're implemented on demand.
+
+        self.configname = configname
+        cflags = []
+
+        sdk_root = self._SdkPath()
+        if "SDKROOT" in self._Settings() and sdk_root:
+            cflags.append("-isysroot %s" % sdk_root)
+
+        if self.header_map_path:
+            cflags.append("-I%s" % self.header_map_path)
+
+        if self._Test("CLANG_WARN_CONSTANT_CONVERSION", "YES", default="NO"):
+            cflags.append("-Wconstant-conversion")
+
+        if self._Test("GCC_CHAR_IS_UNSIGNED_CHAR", "YES", default="NO"):
+            cflags.append("-funsigned-char")
+
+        if self._Test("GCC_CW_ASM_SYNTAX", "YES", default="YES"):
+            cflags.append("-fasm-blocks")
+
+        if "GCC_DYNAMIC_NO_PIC" in self._Settings():
+            if self._Settings()["GCC_DYNAMIC_NO_PIC"] == "YES":
+                cflags.append("-mdynamic-no-pic")
+        else:
+            pass
+            # TODO: In this case, it depends on the target. xcode passes
+            # mdynamic-no-pic by default for executable and possibly static lib
+            # according to mento
+
+        if self._Test("GCC_ENABLE_PASCAL_STRINGS", "YES", default="YES"):
+            cflags.append("-mpascal-strings")
+
+        self._Appendf(cflags, "GCC_OPTIMIZATION_LEVEL", "-O%s", default="s")
+
+        if self._Test("GCC_GENERATE_DEBUGGING_SYMBOLS", "YES", default="YES"):
+            dbg_format = self._Settings().get("DEBUG_INFORMATION_FORMAT", "dwarf")
+            if dbg_format == "dwarf":
+                cflags.append("-gdwarf-2")
+            elif dbg_format == "stabs":
+                raise NotImplementedError("stabs debug format is not supported yet.")
+            elif dbg_format == "dwarf-with-dsym":
+                cflags.append("-gdwarf-2")
+            else:
+                raise NotImplementedError("Unknown debug format %s" % dbg_format)
+
+        if self._Settings().get("GCC_STRICT_ALIASING") == "YES":
+            cflags.append("-fstrict-aliasing")
+        elif self._Settings().get("GCC_STRICT_ALIASING") == "NO":
+            cflags.append("-fno-strict-aliasing")
+
+        if self._Test("GCC_SYMBOLS_PRIVATE_EXTERN", "YES", default="NO"):
+            cflags.append("-fvisibility=hidden")
+
+        if self._Test("GCC_TREAT_WARNINGS_AS_ERRORS", "YES", default="NO"):
+            cflags.append("-Werror")
+
+        if self._Test("GCC_WARN_ABOUT_MISSING_NEWLINE", "YES", default="NO"):
+            cflags.append("-Wnewline-eof")
+
+        # In Xcode, this is only activated when GCC_COMPILER_VERSION is clang or
+        # llvm-gcc. It also requires a fairly recent libtool, and
+        # if the system clang isn't used, DYLD_LIBRARY_PATH needs to contain the
+        # path to the libLTO.dylib that matches the used clang.
+        if self._Test("LLVM_LTO", "YES", default="NO"):
+            cflags.append("-flto")
+
+        self._AppendPlatformVersionMinFlags(cflags)
+
+        # TODO:
+        if self._Test("COPY_PHASE_STRIP", "YES", default="NO"):
+            self._WarnUnimplemented("COPY_PHASE_STRIP")
+        self._WarnUnimplemented("GCC_DEBUGGING_SYMBOLS")
+        self._WarnUnimplemented("GCC_ENABLE_OBJC_EXCEPTIONS")
+
+        # TODO: This is exported correctly, but assigning to it is not supported.
+        self._WarnUnimplemented("MACH_O_TYPE")
+        self._WarnUnimplemented("PRODUCT_TYPE")
+
+        # If GYP_CROSSCOMPILE (--cross-compiling), disable architecture-specific
+        # additions and assume these will be provided as required via CC_host,
+        # CXX_host, CC_target and CXX_target.
+        if not gyp.common.CrossCompileRequested():
+            if arch is not None:
+                archs = [arch]
+            else:
+                assert self.configname
+                archs = self.GetActiveArchs(self.configname)
+            if len(archs) != 1:
+                # TODO: Supporting fat binaries will be annoying.
+                self._WarnUnimplemented("ARCHS")
+                archs = ["i386"]
+            cflags.append("-arch " + archs[0])
+
+            if archs[0] in ("i386", "x86_64"):
+                if self._Test("GCC_ENABLE_SSE3_EXTENSIONS", "YES", default="NO"):
+                    cflags.append("-msse3")
+                if self._Test(
+                    "GCC_ENABLE_SUPPLEMENTAL_SSE3_INSTRUCTIONS", "YES", default="NO"
+                ):
+                    cflags.append("-mssse3")  # Note 3rd 's'.
+                if self._Test("GCC_ENABLE_SSE41_EXTENSIONS", "YES", default="NO"):
+                    cflags.append("-msse4.1")
+                if self._Test("GCC_ENABLE_SSE42_EXTENSIONS", "YES", default="NO"):
+                    cflags.append("-msse4.2")
+
+        cflags += self._Settings().get("WARNING_CFLAGS", [])
+
+        if self._IsXCTest():
+            platform_root = self._XcodePlatformPath(configname)
+            if platform_root:
+                cflags.append("-F" + platform_root + "/Developer/Library/Frameworks/")
+
+        if sdk_root:
+            framework_root = sdk_root
+        else:
+            framework_root = ""
+        config = self.spec["configurations"][self.configname]
+        framework_dirs = config.get("mac_framework_dirs", [])
+        for directory in framework_dirs:
+            cflags.append("-F" + directory.replace("$(SDKROOT)", framework_root))
+
+        self.configname = None
+        return cflags
+
+    def GetCflagsC(self, configname):
+        """Returns flags that need to be added to .c, and .m compilations."""
+        self.configname = configname
+        cflags_c = []
+        if self._Settings().get("GCC_C_LANGUAGE_STANDARD", "") == "ansi":
+            cflags_c.append("-ansi")
+        else:
+            self._Appendf(cflags_c, "GCC_C_LANGUAGE_STANDARD", "-std=%s")
+        cflags_c += self._Settings().get("OTHER_CFLAGS", [])
+        self.configname = None
+        return cflags_c
+
+    def GetCflagsCC(self, configname):
+        """Returns flags that need to be added to .cc, and .mm compilations."""
+        self.configname = configname
+        cflags_cc = []
+
+        clang_cxx_language_standard = self._Settings().get(
+            "CLANG_CXX_LANGUAGE_STANDARD"
+        )
+        # Note: Don't make c++0x to c++11 so that c++0x can be used with older
+        # clangs that don't understand c++11 yet (like Xcode 4.2's).
+        if clang_cxx_language_standard:
+            cflags_cc.append("-std=%s" % clang_cxx_language_standard)
+
+        self._Appendf(cflags_cc, "CLANG_CXX_LIBRARY", "-stdlib=%s")
+
+        if self._Test("GCC_ENABLE_CPP_RTTI", "NO", default="YES"):
+            cflags_cc.append("-fno-rtti")
+        if self._Test("GCC_ENABLE_CPP_EXCEPTIONS", "NO", default="YES"):
+            cflags_cc.append("-fno-exceptions")
+        if self._Test("GCC_INLINES_ARE_PRIVATE_EXTERN", "YES", default="NO"):
+            cflags_cc.append("-fvisibility-inlines-hidden")
+        if self._Test("GCC_THREADSAFE_STATICS", "NO", default="YES"):
+            cflags_cc.append("-fno-threadsafe-statics")
+        # Note: This flag is a no-op for clang, it only has an effect for gcc.
+        if self._Test("GCC_WARN_ABOUT_INVALID_OFFSETOF_MACRO", "NO", default="YES"):
+            cflags_cc.append("-Wno-invalid-offsetof")
+
+        other_ccflags = []
+
+        for flag in self._Settings().get("OTHER_CPLUSPLUSFLAGS", ["$(inherited)"]):
+            # TODO: More general variable expansion. Missing in many other places too.
+            if flag in ("$inherited", "$(inherited)", "${inherited}"):
+                flag = "$OTHER_CFLAGS"
+            if flag in ("$OTHER_CFLAGS", "$(OTHER_CFLAGS)", "${OTHER_CFLAGS}"):
+                other_ccflags += self._Settings().get("OTHER_CFLAGS", [])
+            else:
+                other_ccflags.append(flag)
+        cflags_cc += other_ccflags
+
+        self.configname = None
+        return cflags_cc
+
+    def _AddObjectiveCGarbageCollectionFlags(self, flags):
+        gc_policy = self._Settings().get("GCC_ENABLE_OBJC_GC", "unsupported")
+        if gc_policy == "supported":
+            flags.append("-fobjc-gc")
+        elif gc_policy == "required":
+            flags.append("-fobjc-gc-only")
+
+    def _AddObjectiveCARCFlags(self, flags):
+        if self._Test("CLANG_ENABLE_OBJC_ARC", "YES", default="NO"):
+            flags.append("-fobjc-arc")
+
+    def _AddObjectiveCMissingPropertySynthesisFlags(self, flags):
+        if self._Test(
+            "CLANG_WARN_OBJC_MISSING_PROPERTY_SYNTHESIS", "YES", default="NO"
+        ):
+            flags.append("-Wobjc-missing-property-synthesis")
+
+    def GetCflagsObjC(self, configname):
+        """Returns flags that need to be added to .m compilations."""
+        self.configname = configname
+        cflags_objc = []
+        self._AddObjectiveCGarbageCollectionFlags(cflags_objc)
+        self._AddObjectiveCARCFlags(cflags_objc)
+        self._AddObjectiveCMissingPropertySynthesisFlags(cflags_objc)
+        self.configname = None
+        return cflags_objc
+
+    def GetCflagsObjCC(self, configname):
+        """Returns flags that need to be added to .mm compilations."""
+        self.configname = configname
+        cflags_objcc = []
+        self._AddObjectiveCGarbageCollectionFlags(cflags_objcc)
+        self._AddObjectiveCARCFlags(cflags_objcc)
+        self._AddObjectiveCMissingPropertySynthesisFlags(cflags_objcc)
+        if self._Test("GCC_OBJC_CALL_CXX_CDTORS", "YES", default="NO"):
+            cflags_objcc.append("-fobjc-call-cxx-cdtors")
+        self.configname = None
+        return cflags_objcc
+
+    def GetInstallNameBase(self):
+        """Return DYLIB_INSTALL_NAME_BASE for this target."""
+        # Xcode sets this for shared_libraries, and for nonbundled loadable_modules.
+        if self.spec["type"] != "shared_library" and (
+            self.spec["type"] != "loadable_module" or self._IsBundle()
+        ):
+            return None
+        install_base = self.GetPerTargetSetting(
+            "DYLIB_INSTALL_NAME_BASE",
+            default="/Library/Frameworks" if self._IsBundle() else "/usr/local/lib",
+        )
+        return install_base
+
+    def _StandardizePath(self, path):
+        """Do :standardizepath processing for path."""
+        # I'm not quite sure what :standardizepath does. Just call normpath(),
+        # but don't let @executable_path/../foo collapse to foo.
+        if "/" in path:
+            prefix, rest = "", path
+            if path.startswith("@"):
+                prefix, rest = path.split("/", 1)
+            rest = os.path.normpath(rest)  # :standardizepath
+            path = os.path.join(prefix, rest)
+        return path
+
+    def GetInstallName(self):
+        """Return LD_DYLIB_INSTALL_NAME for this target."""
+        # Xcode sets this for shared_libraries, and for nonbundled loadable_modules.
+        if self.spec["type"] != "shared_library" and (
+            self.spec["type"] != "loadable_module" or self._IsBundle()
+        ):
+            return None
+
+        default_install_name = (
+            "$(DYLIB_INSTALL_NAME_BASE:standardizepath)/$(EXECUTABLE_PATH)"
+        )
+        install_name = self.GetPerTargetSetting(
+            "LD_DYLIB_INSTALL_NAME", default=default_install_name
+        )
+
+        # Hardcode support for the variables used in chromium for now, to
+        # unblock people using the make build.
+        if "$" in install_name:
+            assert install_name in (
+                "$(DYLIB_INSTALL_NAME_BASE:standardizepath)/"
+                "$(WRAPPER_NAME)/$(PRODUCT_NAME)",
+                default_install_name,
+            ), (
+                "Variables in LD_DYLIB_INSTALL_NAME are not generally supported "
+                "yet in target '%s' (got '%s')"
+                % (self.spec["target_name"], install_name)
+            )
+
+            install_name = install_name.replace(
+                "$(DYLIB_INSTALL_NAME_BASE:standardizepath)",
+                self._StandardizePath(self.GetInstallNameBase()),
+            )
+            if self._IsBundle():
+                # These are only valid for bundles, hence the |if|.
+                install_name = install_name.replace(
+                    "$(WRAPPER_NAME)", self.GetWrapperName()
+                )
+                install_name = install_name.replace(
+                    "$(PRODUCT_NAME)", self.GetProductName()
+                )
+            else:
+                assert "$(WRAPPER_NAME)" not in install_name
+                assert "$(PRODUCT_NAME)" not in install_name
+
+            install_name = install_name.replace(
+                "$(EXECUTABLE_PATH)", self.GetExecutablePath()
+            )
+        return install_name
+
+    def _MapLinkerFlagFilename(self, ldflag, gyp_to_build_path):
+        """Checks if ldflag contains a filename and if so remaps it from
+    gyp-directory-relative to build-directory-relative."""
+        # This list is expanded on demand.
+        # They get matched as:
+        #   -exported_symbols_list file
+        #   -Wl,exported_symbols_list file
+        #   -Wl,exported_symbols_list,file
+        LINKER_FILE = r"(\S+)"
+        WORD = r"\S+"
+        linker_flags = [
+            ["-exported_symbols_list", LINKER_FILE],  # Needed for NaCl.
+            ["-unexported_symbols_list", LINKER_FILE],
+            ["-reexported_symbols_list", LINKER_FILE],
+            ["-sectcreate", WORD, WORD, LINKER_FILE],  # Needed for remoting.
+        ]
+        for flag_pattern in linker_flags:
+            regex = re.compile("(?:-Wl,)?" + "[ ,]".join(flag_pattern))
+            m = regex.match(ldflag)
+            if m:
+                ldflag = (
+                    ldflag[: m.start(1)]
+                    + gyp_to_build_path(m.group(1))
+                    + ldflag[m.end(1) :]
+                )
+        # Required for ffmpeg (no idea why they don't use LIBRARY_SEARCH_PATHS,
+        # TODO(thakis): Update ffmpeg.gyp):
+        if ldflag.startswith("-L"):
+            ldflag = "-L" + gyp_to_build_path(ldflag[len("-L") :])
+        return ldflag
+
+    def GetLdflags(self, configname, product_dir, gyp_to_build_path, arch=None):
+        """Returns flags that need to be passed to the linker.
+
+    Args:
+        configname: The name of the configuration to get ld flags for.
+        product_dir: The directory where products such static and dynamic
+            libraries are placed. This is added to the library search path.
+        gyp_to_build_path: A function that converts paths relative to the
+            current gyp file to paths relative to the build directory.
+    """
+        self.configname = configname
+        ldflags = []
+
+        # The xcode build is relative to a gyp file's directory, and OTHER_LDFLAGS
+        # can contain entries that depend on this. Explicitly absolutify these.
+        for ldflag in self._Settings().get("OTHER_LDFLAGS", []):
+            ldflags.append(self._MapLinkerFlagFilename(ldflag, gyp_to_build_path))
+
+        if self._Test("DEAD_CODE_STRIPPING", "YES", default="NO"):
+            ldflags.append("-Wl,-dead_strip")
+
+        if self._Test("PREBINDING", "YES", default="NO"):
+            ldflags.append("-Wl,-prebind")
+
+        self._Appendf(
+            ldflags, "DYLIB_COMPATIBILITY_VERSION", "-compatibility_version %s"
+        )
+        self._Appendf(ldflags, "DYLIB_CURRENT_VERSION", "-current_version %s")
+
+        self._AppendPlatformVersionMinFlags(ldflags)
+
+        if "SDKROOT" in self._Settings() and self._SdkPath():
+            ldflags.append("-isysroot " + self._SdkPath())
+
+        for library_path in self._Settings().get("LIBRARY_SEARCH_PATHS", []):
+            ldflags.append("-L" + gyp_to_build_path(library_path))
+
+        if "ORDER_FILE" in self._Settings():
+            ldflags.append(
+                "-Wl,-order_file "
+                + "-Wl,"
+                + gyp_to_build_path(self._Settings()["ORDER_FILE"])
+            )
+
+        if not gyp.common.CrossCompileRequested():
+            if arch is not None:
+                archs = [arch]
+            else:
+                assert self.configname
+                archs = self.GetActiveArchs(self.configname)
+            if len(archs) != 1:
+                # TODO: Supporting fat binaries will be annoying.
+                self._WarnUnimplemented("ARCHS")
+                archs = ["i386"]
+            ldflags.append("-arch " + archs[0])
+
+        # Xcode adds the product directory by default.
+        # Rewrite -L. to -L./ to work around http://www.openradar.me/25313838
+        ldflags.append("-L" + (product_dir if product_dir != "." else "./"))
+
+        install_name = self.GetInstallName()
+        if install_name and self.spec["type"] != "loadable_module":
+            ldflags.append("-install_name " + install_name.replace(" ", r"\ "))
+
+        for rpath in self._Settings().get("LD_RUNPATH_SEARCH_PATHS", []):
+            ldflags.append("-Wl,-rpath," + rpath)
+
+        sdk_root = self._SdkPath()
+        if not sdk_root:
+            sdk_root = ""
+        config = self.spec["configurations"][self.configname]
+        framework_dirs = config.get("mac_framework_dirs", [])
+        for directory in framework_dirs:
+            ldflags.append("-F" + directory.replace("$(SDKROOT)", sdk_root))
+
+        if self._IsXCTest():
+            platform_root = self._XcodePlatformPath(configname)
+            if sdk_root and platform_root:
+                ldflags.append("-F" + platform_root + "/Developer/Library/Frameworks/")
+                ldflags.append("-framework XCTest")
+
+        is_extension = self._IsIosAppExtension() or self._IsIosWatchKitExtension()
+        if sdk_root and is_extension:
+            # Adds the link flags for extensions. These flags are common for all
+            # extensions and provide loader and main function.
+            # These flags reflect the compilation options used by xcode to compile
+            # extensions.
+            xcode_version, _ = XcodeVersion()
+            if xcode_version < "0900":
+                ldflags.append("-lpkstart")
+                ldflags.append(
+                    sdk_root
+                    + "/System/Library/PrivateFrameworks/PlugInKit.framework/PlugInKit"
+                )
+            else:
+                ldflags.append("-e _NSExtensionMain")
+            ldflags.append("-fapplication-extension")
+
+        self._Appendf(ldflags, "CLANG_CXX_LIBRARY", "-stdlib=%s")
+
+        self.configname = None
+        return ldflags
+
+    def GetLibtoolflags(self, configname):
+        """Returns flags that need to be passed to the static linker.
+
+    Args:
+        configname: The name of the configuration to get ld flags for.
+    """
+        self.configname = configname
+        libtoolflags = []
+
+        for libtoolflag in self._Settings().get("OTHER_LDFLAGS", []):
+            libtoolflags.append(libtoolflag)
+        # TODO(thakis): ARCHS?
+
+        self.configname = None
+        return libtoolflags
+
+    def GetPerTargetSettings(self):
+        """Gets a list of all the per-target settings. This will only fetch keys
+    whose values are the same across all configurations."""
+        first_pass = True
+        result = {}
+        for configname in sorted(self.xcode_settings.keys()):
+            if first_pass:
+                result = dict(self.xcode_settings[configname])
+                first_pass = False
+            else:
+                for key, value in self.xcode_settings[configname].items():
+                    if key not in result:
+                        continue
+                    elif result[key] != value:
+                        del result[key]
+        return result
+
+    def GetPerConfigSetting(self, setting, configname, default=None):
+        if configname in self.xcode_settings:
+            return self.xcode_settings[configname].get(setting, default)
+        else:
+            return self.GetPerTargetSetting(setting, default)
+
+    def GetPerTargetSetting(self, setting, default=None):
+        """Tries to get xcode_settings.setting from spec. Assumes that the setting
+       has the same value in all configurations and throws otherwise."""
+        is_first_pass = True
+        result = None
+        for configname in sorted(self.xcode_settings.keys()):
+            if is_first_pass:
+                result = self.xcode_settings[configname].get(setting, None)
+                is_first_pass = False
+            else:
+                assert result == self.xcode_settings[configname].get(setting, None), (
+                    "Expected per-target setting for '%s', got per-config setting "
+                    "(target %s)" % (setting, self.spec["target_name"])
+                )
+        if result is None:
+            return default
+        return result
+
+    def _GetStripPostbuilds(self, configname, output_binary, quiet):
+        """Returns a list of shell commands that contain the shell commands
+    necessary to strip this target's binary. These should be run as postbuilds
+    before the actual postbuilds run."""
+        self.configname = configname
+
+        result = []
+        if self._Test("DEPLOYMENT_POSTPROCESSING", "YES", default="NO") and self._Test(
+            "STRIP_INSTALLED_PRODUCT", "YES", default="NO"
+        ):
+
+            default_strip_style = "debugging"
+            if (
+                self.spec["type"] == "loadable_module" or self._IsIosAppExtension()
+            ) and self._IsBundle():
+                default_strip_style = "non-global"
+            elif self.spec["type"] == "executable":
+                default_strip_style = "all"
+
+            strip_style = self._Settings().get("STRIP_STYLE", default_strip_style)
+            strip_flags = {"all": "", "non-global": "-x", "debugging": "-S"}[
+                strip_style
+            ]
+
+            explicit_strip_flags = self._Settings().get("STRIPFLAGS", "")
+            if explicit_strip_flags:
+                strip_flags += " " + _NormalizeEnvVarReferences(explicit_strip_flags)
+
+            if not quiet:
+                result.append("echo STRIP\$%s\$" % self.spec["target_name"])
+            result.append(f"strip {strip_flags} {output_binary}")
+
+        self.configname = None
+        return result
+
+    def _GetDebugInfoPostbuilds(self, configname, output, output_binary, quiet):
+        """Returns a list of shell commands that contain the shell commands
+    necessary to massage this target's debug information. These should be run
+    as postbuilds before the actual postbuilds run."""
+        self.configname = configname
+
+        # For static libraries, no dSYMs are created.
+        result = []
+        if (
+            self._Test("GCC_GENERATE_DEBUGGING_SYMBOLS", "YES", default="YES")
+            and self._Test(
+                "DEBUG_INFORMATION_FORMAT", "dwarf-with-dsym", default="dwarf"
+            )
+            and self.spec["type"] != "static_library"
+        ):
+            if not quiet:
+                result.append("echo DSYMUTIL\$%s\$" % self.spec["target_name"])
+            result.append("dsymutil {} -o {}".format(output_binary, output + ".dSYM"))
+
+        self.configname = None
+        return result
+
+    def _GetTargetPostbuilds(self, configname, output, output_binary, quiet=False):
+        """Returns a list of shell commands that contain the shell commands
+    to run as postbuilds for this target, before the actual postbuilds."""
+        # dSYMs need to build before stripping happens.
+        return self._GetDebugInfoPostbuilds(
+            configname, output, output_binary, quiet
+        ) + self._GetStripPostbuilds(configname, output_binary, quiet)
+
+    def _GetIOSPostbuilds(self, configname, output_binary):
+        """Return a shell command to codesign the iOS output binary so it can
+    be deployed to a device.  This should be run as the very last step of the
+    build."""
+        if not (
+            self.isIOS
+            and (self.spec["type"] == "executable" or self._IsXCTest())
+            or self.IsIosFramework()
+        ):
+            return []
+
+        postbuilds = []
+        product_name = self.GetFullProductName()
+        settings = self.xcode_settings[configname]
+
+        # Xcode expects XCTests to be copied into the TEST_HOST dir.
+        if self._IsXCTest():
+            source = os.path.join("${BUILT_PRODUCTS_DIR}", product_name)
+            test_host = os.path.dirname(settings.get("TEST_HOST"))
+            xctest_destination = os.path.join(test_host, "PlugIns", product_name)
+            postbuilds.extend([f"ditto {source} {xctest_destination}"])
+
+        key = self._GetIOSCodeSignIdentityKey(settings)
+        if not key:
+            return postbuilds
+
+        # Warn for any unimplemented signing xcode keys.
+        unimpl = ["OTHER_CODE_SIGN_FLAGS"]
+        unimpl = set(unimpl) & set(self.xcode_settings[configname].keys())
+        if unimpl:
+            print(
+                "Warning: Some codesign keys not implemented, ignoring: %s"
+                % ", ".join(sorted(unimpl))
+            )
+
+        if self._IsXCTest():
+            # For device xctests, Xcode copies two extra frameworks into $TEST_HOST.
+            test_host = os.path.dirname(settings.get("TEST_HOST"))
+            frameworks_dir = os.path.join(test_host, "Frameworks")
+            platform_root = self._XcodePlatformPath(configname)
+            frameworks = [
+                "Developer/Library/PrivateFrameworks/IDEBundleInjection.framework",
+                "Developer/Library/Frameworks/XCTest.framework",
+            ]
+            for framework in frameworks:
+                source = os.path.join(platform_root, framework)
+                destination = os.path.join(frameworks_dir, os.path.basename(framework))
+                postbuilds.extend([f"ditto {source} {destination}"])
+
+                # Then re-sign everything with 'preserve=True'
+                postbuilds.extend(
+                    [
+                        '%s code-sign-bundle "%s" "%s" "%s" "%s" %s'
+                        % (
+                            os.path.join("${TARGET_BUILD_DIR}", "gyp-mac-tool"),
+                            key,
+                            settings.get("CODE_SIGN_ENTITLEMENTS", ""),
+                            settings.get("PROVISIONING_PROFILE", ""),
+                            destination,
+                            True,
+                        )
+                    ]
+                )
+            plugin_dir = os.path.join(test_host, "PlugIns")
+            targets = [os.path.join(plugin_dir, product_name), test_host]
+            for target in targets:
+                postbuilds.extend(
+                    [
+                        '%s code-sign-bundle "%s" "%s" "%s" "%s" %s'
+                        % (
+                            os.path.join("${TARGET_BUILD_DIR}", "gyp-mac-tool"),
+                            key,
+                            settings.get("CODE_SIGN_ENTITLEMENTS", ""),
+                            settings.get("PROVISIONING_PROFILE", ""),
+                            target,
+                            True,
+                        )
+                    ]
+                )
+
+        postbuilds.extend(
+            [
+                '%s code-sign-bundle "%s" "%s" "%s" "%s" %s'
+                % (
+                    os.path.join("${TARGET_BUILD_DIR}", "gyp-mac-tool"),
+                    key,
+                    settings.get("CODE_SIGN_ENTITLEMENTS", ""),
+                    settings.get("PROVISIONING_PROFILE", ""),
+                    os.path.join("${BUILT_PRODUCTS_DIR}", product_name),
+                    False,
+                )
+            ]
+        )
+        return postbuilds
+
+    def _GetIOSCodeSignIdentityKey(self, settings):
+        identity = settings.get("CODE_SIGN_IDENTITY")
+        if not identity:
+            return None
+        if identity not in XcodeSettings._codesigning_key_cache:
+            output = subprocess.check_output(
+                ["security", "find-identity", "-p", "codesigning", "-v"]
+            )
+            for line in output.splitlines():
+                if identity in line:
+                    fingerprint = line.split()[1]
+                    cache = XcodeSettings._codesigning_key_cache
+                    assert identity not in cache or fingerprint == cache[identity], (
+                        "Multiple codesigning fingerprints for identity: %s" % identity
+                    )
+                    XcodeSettings._codesigning_key_cache[identity] = fingerprint
+        return XcodeSettings._codesigning_key_cache.get(identity, "")
+
+    def AddImplicitPostbuilds(
+        self, configname, output, output_binary, postbuilds=[], quiet=False
+    ):
+        """Returns a list of shell commands that should run before and after
+    |postbuilds|."""
+        assert output_binary is not None
+        pre = self._GetTargetPostbuilds(configname, output, output_binary, quiet)
+        post = self._GetIOSPostbuilds(configname, output_binary)
+        return pre + postbuilds + post
+
+    def _AdjustLibrary(self, library, config_name=None):
+        if library.endswith(".framework"):
+            l_flag = "-framework " + os.path.splitext(os.path.basename(library))[0]
+        else:
+            m = self.library_re.match(library)
+            if m:
+                l_flag = "-l" + m.group(1)
+            else:
+                l_flag = library
+
+        sdk_root = self._SdkPath(config_name)
+        if not sdk_root:
+            sdk_root = ""
+        # Xcode 7 started shipping with ".tbd" (text based stubs) files instead of
+        # ".dylib" without providing a real support for them. What it does, for
+        # "/usr/lib" libraries, is do "-L/usr/lib -lname" which is dependent on the
+        # library order and cause collision when building Chrome.
+        #
+        # Instead substitute ".tbd" to ".dylib" in the generated project when the
+        # following conditions are both true:
+        # - library is referenced in the gyp file as "$(SDKROOT)/**/*.dylib",
+        # - the ".dylib" file does not exists but a ".tbd" file do.
+        library = l_flag.replace("$(SDKROOT)", sdk_root)
+        if l_flag.startswith("$(SDKROOT)"):
+            basename, ext = os.path.splitext(library)
+            if ext == ".dylib" and not os.path.exists(library):
+                tbd_library = basename + ".tbd"
+                if os.path.exists(tbd_library):
+                    library = tbd_library
+        return library
+
+    def AdjustLibraries(self, libraries, config_name=None):
+        """Transforms entries like 'Cocoa.framework' in libraries into entries like
+    '-framework Cocoa', 'libcrypto.dylib' into '-lcrypto', etc.
+    """
+        libraries = [self._AdjustLibrary(library, config_name) for library in libraries]
+        return libraries
+
+    def _BuildMachineOSBuild(self):
+        return GetStdout(["sw_vers", "-buildVersion"])
+
+    def _XcodeIOSDeviceFamily(self, configname):
+        family = self.xcode_settings[configname].get("TARGETED_DEVICE_FAMILY", "1")
+        return [int(x) for x in family.split(",")]
+
+    def GetExtraPlistItems(self, configname=None):
+        """Returns a dictionary with extra items to insert into Info.plist."""
+        if configname not in XcodeSettings._plist_cache:
+            cache = {}
+            cache["BuildMachineOSBuild"] = self._BuildMachineOSBuild()
+
+            xcode_version, xcode_build = XcodeVersion()
+            cache["DTXcode"] = xcode_version
+            cache["DTXcodeBuild"] = xcode_build
+            compiler = self.xcode_settings[configname].get("GCC_VERSION")
+            if compiler is not None:
+                cache["DTCompiler"] = compiler
+
+            sdk_root = self._SdkRoot(configname)
+            if not sdk_root:
+                sdk_root = self._DefaultSdkRoot()
+            sdk_version = self._GetSdkVersionInfoItem(sdk_root, "--show-sdk-version")
+            cache["DTSDKName"] = sdk_root + (sdk_version or "")
+            if xcode_version >= "0720":
+                cache["DTSDKBuild"] = self._GetSdkVersionInfoItem(
+                    sdk_root, "--show-sdk-build-version"
+                )
+            elif xcode_version >= "0430":
+                cache["DTSDKBuild"] = sdk_version
+            else:
+                cache["DTSDKBuild"] = cache["BuildMachineOSBuild"]
+
+            if self.isIOS:
+                cache["MinimumOSVersion"] = self.xcode_settings[configname].get(
+                    "IPHONEOS_DEPLOYMENT_TARGET"
+                )
+                cache["DTPlatformName"] = sdk_root
+                cache["DTPlatformVersion"] = sdk_version
+
+                if configname.endswith("iphoneos"):
+                    cache["CFBundleSupportedPlatforms"] = ["iPhoneOS"]
+                    cache["DTPlatformBuild"] = cache["DTSDKBuild"]
+                else:
+                    cache["CFBundleSupportedPlatforms"] = ["iPhoneSimulator"]
+                    # This is weird, but Xcode sets DTPlatformBuild to an empty field
+                    # for simulator builds.
+                    cache["DTPlatformBuild"] = ""
+            XcodeSettings._plist_cache[configname] = cache
+
+        # Include extra plist items that are per-target, not per global
+        # XcodeSettings.
+        items = dict(XcodeSettings._plist_cache[configname])
+        if self.isIOS:
+            items["UIDeviceFamily"] = self._XcodeIOSDeviceFamily(configname)
+        return items
+
+    def _DefaultSdkRoot(self):
+        """Returns the default SDKROOT to use.
+
+    Prior to version 5.0.0, if SDKROOT was not explicitly set in the Xcode
+    project, then the environment variable was empty. Starting with this
+    version, Xcode uses the name of the newest SDK installed.
+    """
+        xcode_version, _ = XcodeVersion()
+        if xcode_version < "0500":
+            return ""
+        default_sdk_path = self._XcodeSdkPath("")
+        default_sdk_root = XcodeSettings._sdk_root_cache.get(default_sdk_path)
+        if default_sdk_root:
+            return default_sdk_root
+        try:
+            all_sdks = GetStdout(["xcodebuild", "-showsdks"])
+        except GypError:
+            # If xcodebuild fails, there will be no valid SDKs
+            return ""
+        for line in all_sdks.splitlines():
+            items = line.split()
+            if len(items) >= 3 and items[-2] == "-sdk":
+                sdk_root = items[-1]
+                sdk_path = self._XcodeSdkPath(sdk_root)
+                if sdk_path == default_sdk_path:
+                    return sdk_root
+        return ""
+
+
+class MacPrefixHeader:
+    """A class that helps with emulating Xcode's GCC_PREFIX_HEADER feature.
+
+  This feature consists of several pieces:
+  * If GCC_PREFIX_HEADER is present, all compilations in that project get an
+    additional |-include path_to_prefix_header| cflag.
+  * If GCC_PRECOMPILE_PREFIX_HEADER is present too, then the prefix header is
+    instead compiled, and all other compilations in the project get an
+    additional |-include path_to_compiled_header| instead.
+    + Compiled prefix headers have the extension gch. There is one gch file for
+      every language used in the project (c, cc, m, mm), since gch files for
+      different languages aren't compatible.
+    + gch files themselves are built with the target's normal cflags, but they
+      obviously don't get the |-include| flag. Instead, they need a -x flag that
+      describes their language.
+    + All o files in the target need to depend on the gch file, to make sure
+      it's built before any o file is built.
+
+  This class helps with some of these tasks, but it needs help from the build
+  system for writing dependencies to the gch files, for writing build commands
+  for the gch files, and for figuring out the location of the gch files.
+  """
+
+    def __init__(
+        self, xcode_settings, gyp_path_to_build_path, gyp_path_to_build_output
+    ):
+        """If xcode_settings is None, all methods on this class are no-ops.
+
+    Args:
+        gyp_path_to_build_path: A function that takes a gyp-relative path,
+            and returns a path relative to the build directory.
+        gyp_path_to_build_output: A function that takes a gyp-relative path and
+            a language code ('c', 'cc', 'm', or 'mm'), and that returns a path
+            to where the output of precompiling that path for that language
+            should be placed (without the trailing '.gch').
+    """
+        # This doesn't support per-configuration prefix headers. Good enough
+        # for now.
+        self.header = None
+        self.compile_headers = False
+        if xcode_settings:
+            self.header = xcode_settings.GetPerTargetSetting("GCC_PREFIX_HEADER")
+            self.compile_headers = (
+                xcode_settings.GetPerTargetSetting(
+                    "GCC_PRECOMPILE_PREFIX_HEADER", default="NO"
+                )
+                != "NO"
+            )
+        self.compiled_headers = {}
+        if self.header:
+            if self.compile_headers:
+                for lang in ["c", "cc", "m", "mm"]:
+                    self.compiled_headers[lang] = gyp_path_to_build_output(
+                        self.header, lang
+                    )
+            self.header = gyp_path_to_build_path(self.header)
+
+    def _CompiledHeader(self, lang, arch):
+        assert self.compile_headers
+        h = self.compiled_headers[lang]
+        if arch:
+            h += "." + arch
+        return h
+
+    def GetInclude(self, lang, arch=None):
+        """Gets the cflags to include the prefix header for language |lang|."""
+        if self.compile_headers and lang in self.compiled_headers:
+            return "-include %s" % self._CompiledHeader(lang, arch)
+        elif self.header:
+            return "-include %s" % self.header
+        else:
+            return ""
+
+    def _Gch(self, lang, arch):
+        """Returns the actual file name of the prefix header for language |lang|."""
+        assert self.compile_headers
+        return self._CompiledHeader(lang, arch) + ".gch"
+
+    def GetObjDependencies(self, sources, objs, arch=None):
+        """Given a list of source files and the corresponding object files, returns
+    a list of (source, object, gch) tuples, where |gch| is the build-directory
+    relative path to the gch file each object file depends on.  |compilable[i]|
+    has to be the source file belonging to |objs[i]|."""
+        if not self.header or not self.compile_headers:
+            return []
+
+        result = []
+        for source, obj in zip(sources, objs):
+            ext = os.path.splitext(source)[1]
+            lang = {
+                ".c": "c",
+                ".cpp": "cc",
+                ".cc": "cc",
+                ".cxx": "cc",
+                ".m": "m",
+                ".mm": "mm",
+            }.get(ext, None)
+            if lang:
+                result.append((source, obj, self._Gch(lang, arch)))
+        return result
+
+    def GetPchBuildCommands(self, arch=None):
+        """Returns [(path_to_gch, language_flag, language, header)].
+    |path_to_gch| and |header| are relative to the build directory.
+    """
+        if not self.header or not self.compile_headers:
+            return []
+        return [
+            (self._Gch("c", arch), "-x c-header", "c", self.header),
+            (self._Gch("cc", arch), "-x c++-header", "cc", self.header),
+            (self._Gch("m", arch), "-x objective-c-header", "m", self.header),
+            (self._Gch("mm", arch), "-x objective-c++-header", "mm", self.header),
+        ]
+
+
+def XcodeVersion():
+    """Returns a tuple of version and build version of installed Xcode."""
+    # `xcodebuild -version` output looks like
+    #    Xcode 4.6.3
+    #    Build version 4H1503
+    # or like
+    #    Xcode 3.2.6
+    #    Component versions: DevToolsCore-1809.0; DevToolsSupport-1806.0
+    #    BuildVersion: 10M2518
+    # Convert that to ('0463', '4H1503') or ('0326', '10M2518').
+    global XCODE_VERSION_CACHE
+    if XCODE_VERSION_CACHE:
+        return XCODE_VERSION_CACHE
+    version = ""
+    build = ""
+    try:
+        version_list = GetStdoutQuiet(["xcodebuild", "-version"]).splitlines()
+        # In some circumstances xcodebuild exits 0 but doesn't return
+        # the right results; for example, a user on 10.7 or 10.8 with
+        # a bogus path set via xcode-select
+        # In that case this may be a CLT-only install so fall back to
+        # checking that version.
+        if len(version_list) < 2:
+            raise GypError("xcodebuild returned unexpected results")
+        version = version_list[0].split()[-1]  # Last word on first line
+        build = version_list[-1].split()[-1]  # Last word on last line
+    except GypError:  # Xcode not installed so look for XCode Command Line Tools
+        version = CLTVersion()  # macOS Catalina returns 11.0.0.0.1.1567737322
+        if not version:
+            raise GypError("No Xcode or CLT version detected!")
+    # Be careful to convert "4.2.3" to "0423" and "11.0.0" to "1100":
+    version = version.split(".")[:3]  # Just major, minor, micro
+    version[0] = version[0].zfill(2)  # Add a leading zero if major is one digit
+    version = ("".join(version) + "00")[:4]  # Limit to exactly four characters
+    XCODE_VERSION_CACHE = (version, build)
+    return XCODE_VERSION_CACHE
+
+
+# This function ported from the logic in Homebrew's CLT version check
+def CLTVersion():
+    """Returns the version of command-line tools from pkgutil."""
+    # pkgutil output looks like
+    #   package-id: com.apple.pkg.CLTools_Executables
+    #   version: 5.0.1.0.1.1382131676
+    #   volume: /
+    #   location: /
+    #   install-time: 1382544035
+    #   groups: com.apple.FindSystemFiles.pkg-group
+    #           com.apple.DevToolsBoth.pkg-group
+    #           com.apple.DevToolsNonRelocatableShared.pkg-group
+    STANDALONE_PKG_ID = "com.apple.pkg.DeveloperToolsCLILeo"
+    FROM_XCODE_PKG_ID = "com.apple.pkg.DeveloperToolsCLI"
+    MAVERICKS_PKG_ID = "com.apple.pkg.CLTools_Executables"
+
+    regex = re.compile("version: (?P<version>.+)")
+    for key in [MAVERICKS_PKG_ID, STANDALONE_PKG_ID, FROM_XCODE_PKG_ID]:
+        try:
+            output = GetStdout(["/usr/sbin/pkgutil", "--pkg-info", key])
+            return re.search(regex, output).groupdict()["version"]
+        except GypError:
+            continue
+
+    regex = re.compile(r'Command Line Tools for Xcode\s+(?P<version>\S+)')
+    try:
+        output = GetStdout(["/usr/sbin/softwareupdate", "--history"])
+        return re.search(regex, output).groupdict()["version"]
+    except GypError:
+        return None
+
+
+def GetStdoutQuiet(cmdlist):
+    """Returns the content of standard output returned by invoking |cmdlist|.
+  Ignores the stderr.
+  Raises |GypError| if the command return with a non-zero return code."""
+    job = subprocess.Popen(cmdlist, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    out = job.communicate()[0].decode("utf-8")
+    if job.returncode != 0:
+        raise GypError("Error %d running %s" % (job.returncode, cmdlist[0]))
+    return out.rstrip("\n")
+
+
+def GetStdout(cmdlist):
+    """Returns the content of standard output returned by invoking |cmdlist|.
+  Raises |GypError| if the command return with a non-zero return code."""
+    job = subprocess.Popen(cmdlist, stdout=subprocess.PIPE)
+    out = job.communicate()[0].decode("utf-8")
+    if job.returncode != 0:
+        sys.stderr.write(out + "\n")
+        raise GypError("Error %d running %s" % (job.returncode, cmdlist[0]))
+    return out.rstrip("\n")
+
+
+def MergeGlobalXcodeSettingsToSpec(global_dict, spec):
+    """Merges the global xcode_settings dictionary into each configuration of the
+  target represented by spec. For keys that are both in the global and the local
+  xcode_settings dict, the local key gets precedence.
+  """
+    # The xcode generator special-cases global xcode_settings and does something
+    # that amounts to merging in the global xcode_settings into each local
+    # xcode_settings dict.
+    global_xcode_settings = global_dict.get("xcode_settings", {})
+    for config in spec["configurations"].values():
+        if "xcode_settings" in config:
+            new_settings = global_xcode_settings.copy()
+            new_settings.update(config["xcode_settings"])
+            config["xcode_settings"] = new_settings
+
+
+def IsMacBundle(flavor, spec):
+    """Returns if |spec| should be treated as a bundle.
+
+  Bundles are directories with a certain subdirectory structure, instead of
+  just a single file. Bundle rules do not produce a binary but also package
+  resources into that directory."""
+    is_mac_bundle = (
+        int(spec.get("mac_xctest_bundle", 0)) != 0
+        or int(spec.get("mac_xcuitest_bundle", 0)) != 0
+        or (int(spec.get("mac_bundle", 0)) != 0 and flavor == "mac")
+    )
+
+    if is_mac_bundle:
+        assert spec["type"] != "none", (
+            'mac_bundle targets cannot have type none (target "%s")'
+            % spec["target_name"]
+        )
+    return is_mac_bundle
+
+
+def GetMacBundleResources(product_dir, xcode_settings, resources):
+    """Yields (output, resource) pairs for every resource in |resources|.
+  Only call this for mac bundle targets.
+
+  Args:
+      product_dir: Path to the directory containing the output bundle,
+          relative to the build directory.
+      xcode_settings: The XcodeSettings of the current target.
+      resources: A list of bundle resources, relative to the build directory.
+  """
+    dest = os.path.join(product_dir, xcode_settings.GetBundleResourceFolder())
+    for res in resources:
+        output = dest
+
+        # The make generator doesn't support it, so forbid it everywhere
+        # to keep the generators more interchangeable.
+        assert " " not in res, "Spaces in resource filenames not supported (%s)" % res
+
+        # Split into (path,file).
+        res_parts = os.path.split(res)
+
+        # Now split the path into (prefix,maybe.lproj).
+        lproj_parts = os.path.split(res_parts[0])
+        # If the resource lives in a .lproj bundle, add that to the destination.
+        if lproj_parts[1].endswith(".lproj"):
+            output = os.path.join(output, lproj_parts[1])
+
+        output = os.path.join(output, res_parts[1])
+        # Compiled XIB files are referred to by .nib.
+        if output.endswith(".xib"):
+            output = os.path.splitext(output)[0] + ".nib"
+        # Compiled storyboard files are referred to by .storyboardc.
+        if output.endswith(".storyboard"):
+            output = os.path.splitext(output)[0] + ".storyboardc"
+
+        yield output, res
+
+
+def GetMacInfoPlist(product_dir, xcode_settings, gyp_path_to_build_path):
+    """Returns (info_plist, dest_plist, defines, extra_env), where:
+  * |info_plist| is the source plist path, relative to the
+    build directory,
+  * |dest_plist| is the destination plist path, relative to the
+    build directory,
+  * |defines| is a list of preprocessor defines (empty if the plist
+    shouldn't be preprocessed,
+  * |extra_env| is a dict of env variables that should be exported when
+    invoking |mac_tool copy-info-plist|.
+
+  Only call this for mac bundle targets.
+
+  Args:
+      product_dir: Path to the directory containing the output bundle,
+          relative to the build directory.
+      xcode_settings: The XcodeSettings of the current target.
+      gyp_to_build_path: A function that converts paths relative to the
+          current gyp file to paths relative to the build directory.
+  """
+    info_plist = xcode_settings.GetPerTargetSetting("INFOPLIST_FILE")
+    if not info_plist:
+        return None, None, [], {}
+
+    # The make generator doesn't support it, so forbid it everywhere
+    # to keep the generators more interchangeable.
+    assert " " not in info_plist, (
+        "Spaces in Info.plist filenames not supported (%s)" % info_plist
+    )
+
+    info_plist = gyp_path_to_build_path(info_plist)
+
+    # If explicitly set to preprocess the plist, invoke the C preprocessor and
+    # specify any defines as -D flags.
+    if (
+        xcode_settings.GetPerTargetSetting("INFOPLIST_PREPROCESS", default="NO")
+        == "YES"
+    ):
+        # Create an intermediate file based on the path.
+        defines = shlex.split(
+            xcode_settings.GetPerTargetSetting(
+                "INFOPLIST_PREPROCESSOR_DEFINITIONS", default=""
+            )
+        )
+    else:
+        defines = []
+
+    dest_plist = os.path.join(product_dir, xcode_settings.GetBundlePlistPath())
+    extra_env = xcode_settings.GetPerTargetSettings()
+
+    return info_plist, dest_plist, defines, extra_env
+
+
+def _GetXcodeEnv(
+    xcode_settings, built_products_dir, srcroot, configuration, additional_settings=None
+):
+    """Return the environment variables that Xcode would set. See
+  http://developer.apple.com/library/mac/#documentation/DeveloperTools/Reference/XcodeBuildSettingRef/1-Build_Setting_Reference/build_setting_ref.html#//apple_ref/doc/uid/TP40003931-CH3-SW153
+  for a full list.
+
+  Args:
+      xcode_settings: An XcodeSettings object. If this is None, this function
+          returns an empty dict.
+      built_products_dir: Absolute path to the built products dir.
+      srcroot: Absolute path to the source root.
+      configuration: The build configuration name.
+      additional_settings: An optional dict with more values to add to the
+          result.
+  """
+
+    if not xcode_settings:
+        return {}
+
+    # This function is considered a friend of XcodeSettings, so let it reach into
+    # its implementation details.
+    spec = xcode_settings.spec
+
+    # These are filled in on an as-needed basis.
+    env = {
+        "BUILT_FRAMEWORKS_DIR": built_products_dir,
+        "BUILT_PRODUCTS_DIR": built_products_dir,
+        "CONFIGURATION": configuration,
+        "PRODUCT_NAME": xcode_settings.GetProductName(),
+        # For FULL_PRODUCT_NAME see:
+        # /Developer/Platforms/MacOSX.platform/Developer/Library/Xcode/Specifications/MacOSX\ Product\ Types.xcspec  # noqa: E501
+        "SRCROOT": srcroot,
+        "SOURCE_ROOT": "${SRCROOT}",
+        # This is not true for static libraries, but currently the env is only
+        # written for bundles:
+        "TARGET_BUILD_DIR": built_products_dir,
+        "TEMP_DIR": "${TMPDIR}",
+        "XCODE_VERSION_ACTUAL": XcodeVersion()[0],
+    }
+    if xcode_settings.GetPerConfigSetting("SDKROOT", configuration):
+        env["SDKROOT"] = xcode_settings._SdkPath(configuration)
+    else:
+        env["SDKROOT"] = ""
+
+    if xcode_settings.mac_toolchain_dir:
+        env["DEVELOPER_DIR"] = xcode_settings.mac_toolchain_dir
+
+    if spec["type"] in (
+        "executable",
+        "static_library",
+        "shared_library",
+        "loadable_module",
+    ):
+        env["EXECUTABLE_NAME"] = xcode_settings.GetExecutableName()
+        env["EXECUTABLE_PATH"] = xcode_settings.GetExecutablePath()
+        env["FULL_PRODUCT_NAME"] = xcode_settings.GetFullProductName()
+        mach_o_type = xcode_settings.GetMachOType()
+        if mach_o_type:
+            env["MACH_O_TYPE"] = mach_o_type
+        env["PRODUCT_TYPE"] = xcode_settings.GetProductType()
+    if xcode_settings._IsBundle():
+        # xcodeproj_file.py sets the same Xcode subfolder value for this as for
+        # FRAMEWORKS_FOLDER_PATH so Xcode builds will actually use FFP's value.
+        env["BUILT_FRAMEWORKS_DIR"] = os.path.join(
+            built_products_dir + os.sep + xcode_settings.GetBundleFrameworksFolderPath()
+        )
+        env["CONTENTS_FOLDER_PATH"] = xcode_settings.GetBundleContentsFolderPath()
+        env["EXECUTABLE_FOLDER_PATH"] = xcode_settings.GetBundleExecutableFolderPath()
+        env[
+            "UNLOCALIZED_RESOURCES_FOLDER_PATH"
+        ] = xcode_settings.GetBundleResourceFolder()
+        env["JAVA_FOLDER_PATH"] = xcode_settings.GetBundleJavaFolderPath()
+        env["FRAMEWORKS_FOLDER_PATH"] = xcode_settings.GetBundleFrameworksFolderPath()
+        env[
+            "SHARED_FRAMEWORKS_FOLDER_PATH"
+        ] = xcode_settings.GetBundleSharedFrameworksFolderPath()
+        env[
+            "SHARED_SUPPORT_FOLDER_PATH"
+        ] = xcode_settings.GetBundleSharedSupportFolderPath()
+        env["PLUGINS_FOLDER_PATH"] = xcode_settings.GetBundlePlugInsFolderPath()
+        env["XPCSERVICES_FOLDER_PATH"] = xcode_settings.GetBundleXPCServicesFolderPath()
+        env["INFOPLIST_PATH"] = xcode_settings.GetBundlePlistPath()
+        env["WRAPPER_NAME"] = xcode_settings.GetWrapperName()
+
+    install_name = xcode_settings.GetInstallName()
+    if install_name:
+        env["LD_DYLIB_INSTALL_NAME"] = install_name
+    install_name_base = xcode_settings.GetInstallNameBase()
+    if install_name_base:
+        env["DYLIB_INSTALL_NAME_BASE"] = install_name_base
+    xcode_version, _ = XcodeVersion()
+    if xcode_version >= "0500" and not env.get("SDKROOT"):
+        sdk_root = xcode_settings._SdkRoot(configuration)
+        if not sdk_root:
+            sdk_root = xcode_settings._XcodeSdkPath("")
+        if sdk_root is None:
+            sdk_root = ""
+        env["SDKROOT"] = sdk_root
+
+    if not additional_settings:
+        additional_settings = {}
+    else:
+        # Flatten lists to strings.
+        for k in additional_settings:
+            if not isinstance(additional_settings[k], str):
+                additional_settings[k] = " ".join(additional_settings[k])
+    additional_settings.update(env)
+
+    for k in additional_settings:
+        additional_settings[k] = _NormalizeEnvVarReferences(additional_settings[k])
+
+    return additional_settings
+
+
+def _NormalizeEnvVarReferences(str):
+    """Takes a string containing variable references in the form ${FOO}, $(FOO),
+  or $FOO, and returns a string with all variable references in the form ${FOO}.
+  """
+    # $FOO -> ${FOO}
+    str = re.sub(r"\$([a-zA-Z_][a-zA-Z0-9_]*)", r"${\1}", str)
+
+    # $(FOO) -> ${FOO}
+    matches = re.findall(r"(\$$([a-zA-Z0-9\-_]+)$)", str)
+    for match in matches:
+        to_replace, variable = match
+        assert "$(" not in match, "$($(FOO)) variables not supported: " + match
+        str = str.replace(to_replace, "${" + variable + "}")
+
+    return str
+
+
+def ExpandEnvVars(string, expansions):
+    """Expands ${VARIABLES}, $(VARIABLES), and $VARIABLES in string per the
+  expansions list. If the variable expands to something that references
+  another variable, this variable is expanded as well if it's in env --
+  until no variables present in env are left."""
+    for k, v in reversed(expansions):
+        string = string.replace("${" + k + "}", v)
+        string = string.replace("$(" + k + ")", v)
+        string = string.replace("$" + k, v)
+    return string
+
+
+def _TopologicallySortedEnvVarKeys(env):
+    """Takes a dict |env| whose values are strings that can refer to other keys,
+  for example env['foo'] = '$(bar) and $(baz)'. Returns a list L of all keys of
+  env such that key2 is after key1 in L if env[key2] refers to env[key1].
+
+  Throws an Exception in case of dependency cycles.
+  """
+    # Since environment variables can refer to other variables, the evaluation
+    # order is important. Below is the logic to compute the dependency graph
+    # and sort it.
+    regex = re.compile(r"\$\{([a-zA-Z0-9\-_]+)\}")
+
+    def GetEdges(node):
+        # Use a definition of edges such that user_of_variable -> used_varible.
+        # This happens to be easier in this case, since a variable's
+        # definition contains all variables it references in a single string.
+        # We can then reverse the result of the topological sort at the end.
+        # Since: reverse(topsort(DAG)) = topsort(reverse_edges(DAG))
+        matches = {v for v in regex.findall(env[node]) if v in env}
+        for dependee in matches:
+            assert "${" not in dependee, "Nested variables not supported: " + dependee
+        return matches
+
+    try:
+        # Topologically sort, and then reverse, because we used an edge definition
+        # that's inverted from the expected result of this function (see comment
+        # above).
+        order = gyp.common.TopologicallySorted(env.keys(), GetEdges)
+        order.reverse()
+        return order
+    except gyp.common.CycleError as e:
+        raise GypError(
+            "Xcode environment variables are cyclically dependent: " + str(e.nodes)
+        )
+
+
+def GetSortedXcodeEnv(
+    xcode_settings, built_products_dir, srcroot, configuration, additional_settings=None
+):
+    env = _GetXcodeEnv(
+        xcode_settings, built_products_dir, srcroot, configuration, additional_settings
+    )
+    return [(key, env[key]) for key in _TopologicallySortedEnvVarKeys(env)]
+
+
+def GetSpecPostbuildCommands(spec, quiet=False):
+    """Returns the list of postbuilds explicitly defined on |spec|, in a form
+  executable by a shell."""
+    postbuilds = []
+    for postbuild in spec.get("postbuilds", []):
+        if not quiet:
+            postbuilds.append(
+                "echo POSTBUILD\$%s\$ %s"
+                % (spec["target_name"], postbuild["postbuild_name"])
+            )
+        postbuilds.append(gyp.common.EncodePOSIXShellList(postbuild["action"]))
+    return postbuilds
+
+
+def _HasIOSTarget(targets):
+    """Returns true if any target contains the iOS specific key
+  IPHONEOS_DEPLOYMENT_TARGET."""
+    for target_dict in targets.values():
+        for config in target_dict["configurations"].values():
+            if config.get("xcode_settings", {}).get("IPHONEOS_DEPLOYMENT_TARGET"):
+                return True
+    return False
+
+
+def _AddIOSDeviceConfigurations(targets):
+    """Clone all targets and append -iphoneos to the name. Configure these targets
+  to build for iOS devices and use correct architectures for those builds."""
+    for target_dict in targets.values():
+        toolset = target_dict["toolset"]
+        configs = target_dict["configurations"]
+        for config_name, simulator_config_dict in dict(configs).items():
+            iphoneos_config_dict = copy.deepcopy(simulator_config_dict)
+            configs[config_name + "-iphoneos"] = iphoneos_config_dict
+            configs[config_name + "-iphonesimulator"] = simulator_config_dict
+            if toolset == "target":
+                simulator_config_dict["xcode_settings"]["SDKROOT"] = "iphonesimulator"
+                iphoneos_config_dict["xcode_settings"]["SDKROOT"] = "iphoneos"
+    return targets
+
+
+def CloneConfigurationForDeviceAndEmulator(target_dicts):
+    """If |target_dicts| contains any iOS targets, automatically create -iphoneos
+  targets for iOS device builds."""
+    if _HasIOSTarget(target_dicts):
+        return _AddIOSDeviceConfigurations(target_dicts)
+    return target_dicts
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/xcode_ninja.py b/server/node_modules/node-gyp/gyp/pylib/gyp/xcode_ninja.py
new file mode 100644
index 0000000..bb74eac
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/xcode_ninja.py
@@ -0,0 +1,302 @@
+# Copyright (c) 2014 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Xcode-ninja wrapper project file generator.
+
+This updates the data structures passed to the Xcode gyp generator to build
+with ninja instead. The Xcode project itself is transformed into a list of
+executable targets, each with a build step to build with ninja, and a target
+with every source and resource file.  This appears to sidestep some of the
+major performance headaches experienced using complex projects and large number
+of targets within Xcode.
+"""
+
+import errno
+import gyp.generator.ninja
+import os
+import re
+import xml.sax.saxutils
+
+
+def _WriteWorkspace(main_gyp, sources_gyp, params):
+    """ Create a workspace to wrap main and sources gyp paths. """
+    (build_file_root, build_file_ext) = os.path.splitext(main_gyp)
+    workspace_path = build_file_root + ".xcworkspace"
+    options = params["options"]
+    if options.generator_output:
+        workspace_path = os.path.join(options.generator_output, workspace_path)
+    try:
+        os.makedirs(workspace_path)
+    except OSError as e:
+        if e.errno != errno.EEXIST:
+            raise
+    output_string = (
+        '<?xml version="1.0" encoding="UTF-8"?>\n' + '<Workspace version = "1.0">\n'
+    )
+    for gyp_name in [main_gyp, sources_gyp]:
+        name = os.path.splitext(os.path.basename(gyp_name))[0] + ".xcodeproj"
+        name = xml.sax.saxutils.quoteattr("group:" + name)
+        output_string += "  <FileRef location = %s></FileRef>\n" % name
+    output_string += "</Workspace>\n"
+
+    workspace_file = os.path.join(workspace_path, "contents.xcworkspacedata")
+
+    try:
+        with open(workspace_file) as input_file:
+            input_string = input_file.read()
+            if input_string == output_string:
+                return
+    except OSError:
+        # Ignore errors if the file doesn't exist.
+        pass
+
+    with open(workspace_file, "w") as output_file:
+        output_file.write(output_string)
+
+
+def _TargetFromSpec(old_spec, params):
+    """ Create fake target for xcode-ninja wrapper. """
+    # Determine ninja top level build dir (e.g. /path/to/out).
+    ninja_toplevel = None
+    jobs = 0
+    if params:
+        options = params["options"]
+        ninja_toplevel = os.path.join(
+            options.toplevel_dir, gyp.generator.ninja.ComputeOutputDir(params)
+        )
+        jobs = params.get("generator_flags", {}).get("xcode_ninja_jobs", 0)
+
+    target_name = old_spec.get("target_name")
+    product_name = old_spec.get("product_name", target_name)
+    product_extension = old_spec.get("product_extension")
+
+    ninja_target = {}
+    ninja_target["target_name"] = target_name
+    ninja_target["product_name"] = product_name
+    if product_extension:
+        ninja_target["product_extension"] = product_extension
+    ninja_target["toolset"] = old_spec.get("toolset")
+    ninja_target["default_configuration"] = old_spec.get("default_configuration")
+    ninja_target["configurations"] = {}
+
+    # Tell Xcode to look in |ninja_toplevel| for build products.
+    new_xcode_settings = {}
+    if ninja_toplevel:
+        new_xcode_settings["CONFIGURATION_BUILD_DIR"] = (
+            "%s/$(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME)" % ninja_toplevel
+        )
+
+    if "configurations" in old_spec:
+        for config in old_spec["configurations"]:
+            old_xcode_settings = old_spec["configurations"][config].get(
+                "xcode_settings", {}
+            )
+            if "IPHONEOS_DEPLOYMENT_TARGET" in old_xcode_settings:
+                new_xcode_settings["CODE_SIGNING_REQUIRED"] = "NO"
+                new_xcode_settings["IPHONEOS_DEPLOYMENT_TARGET"] = old_xcode_settings[
+                    "IPHONEOS_DEPLOYMENT_TARGET"
+                ]
+            for key in ["BUNDLE_LOADER", "TEST_HOST"]:
+                if key in old_xcode_settings:
+                    new_xcode_settings[key] = old_xcode_settings[key]
+
+            ninja_target["configurations"][config] = {}
+            ninja_target["configurations"][config][
+                "xcode_settings"
+            ] = new_xcode_settings
+
+    ninja_target["mac_bundle"] = old_spec.get("mac_bundle", 0)
+    ninja_target["mac_xctest_bundle"] = old_spec.get("mac_xctest_bundle", 0)
+    ninja_target["ios_app_extension"] = old_spec.get("ios_app_extension", 0)
+    ninja_target["ios_watchkit_extension"] = old_spec.get("ios_watchkit_extension", 0)
+    ninja_target["ios_watchkit_app"] = old_spec.get("ios_watchkit_app", 0)
+    ninja_target["type"] = old_spec["type"]
+    if ninja_toplevel:
+        ninja_target["actions"] = [
+            {
+                "action_name": "Compile and copy %s via ninja" % target_name,
+                "inputs": [],
+                "outputs": [],
+                "action": [
+                    "env",
+                    "PATH=%s" % os.environ["PATH"],
+                    "ninja",
+                    "-C",
+                    new_xcode_settings["CONFIGURATION_BUILD_DIR"],
+                    target_name,
+                ],
+                "message": "Compile and copy %s via ninja" % target_name,
+            },
+        ]
+        if jobs > 0:
+            ninja_target["actions"][0]["action"].extend(("-j", jobs))
+    return ninja_target
+
+
+def IsValidTargetForWrapper(target_extras, executable_target_pattern, spec):
+    """Limit targets for Xcode wrapper.
+
+  Xcode sometimes performs poorly with too many targets, so only include
+  proper executable targets, with filters to customize.
+  Arguments:
+    target_extras: Regular expression to always add, matching any target.
+    executable_target_pattern: Regular expression limiting executable targets.
+    spec: Specifications for target.
+  """
+    target_name = spec.get("target_name")
+    # Always include targets matching target_extras.
+    if target_extras is not None and re.search(target_extras, target_name):
+        return True
+
+    # Otherwise just show executable targets and xc_tests.
+    if int(spec.get("mac_xctest_bundle", 0)) != 0 or (
+        spec.get("type", "") == "executable"
+        and spec.get("product_extension", "") != "bundle"
+    ):
+
+        # If there is a filter and the target does not match, exclude the target.
+        if executable_target_pattern is not None:
+            if not re.search(executable_target_pattern, target_name):
+                return False
+        return True
+    return False
+
+
+def CreateWrapper(target_list, target_dicts, data, params):
+    """Initialize targets for the ninja wrapper.
+
+  This sets up the necessary variables in the targets to generate Xcode projects
+  that use ninja as an external builder.
+  Arguments:
+    target_list: List of target pairs: 'base/base.gyp:base'.
+    target_dicts: Dict of target properties keyed on target pair.
+    data: Dict of flattened build files keyed on gyp path.
+    params: Dict of global options for gyp.
+  """
+    orig_gyp = params["build_files"][0]
+    for gyp_name, gyp_dict in data.items():
+        if gyp_name == orig_gyp:
+            depth = gyp_dict["_DEPTH"]
+
+    # Check for custom main gyp name, otherwise use the default CHROMIUM_GYP_FILE
+    # and prepend .ninja before the .gyp extension.
+    generator_flags = params.get("generator_flags", {})
+    main_gyp = generator_flags.get("xcode_ninja_main_gyp", None)
+    if main_gyp is None:
+        (build_file_root, build_file_ext) = os.path.splitext(orig_gyp)
+        main_gyp = build_file_root + ".ninja" + build_file_ext
+
+    # Create new |target_list|, |target_dicts| and |data| data structures.
+    new_target_list = []
+    new_target_dicts = {}
+    new_data = {}
+
+    # Set base keys needed for |data|.
+    new_data[main_gyp] = {}
+    new_data[main_gyp]["included_files"] = []
+    new_data[main_gyp]["targets"] = []
+    new_data[main_gyp]["xcode_settings"] = data[orig_gyp].get("xcode_settings", {})
+
+    # Normally the xcode-ninja generator includes only valid executable targets.
+    # If |xcode_ninja_executable_target_pattern| is set, that list is reduced to
+    # executable targets that match the pattern. (Default all)
+    executable_target_pattern = generator_flags.get(
+        "xcode_ninja_executable_target_pattern", None
+    )
+
+    # For including other non-executable targets, add the matching target name
+    # to the |xcode_ninja_target_pattern| regular expression. (Default none)
+    target_extras = generator_flags.get("xcode_ninja_target_pattern", None)
+
+    for old_qualified_target in target_list:
+        spec = target_dicts[old_qualified_target]
+        if IsValidTargetForWrapper(target_extras, executable_target_pattern, spec):
+            # Add to new_target_list.
+            target_name = spec.get("target_name")
+            new_target_name = f"{main_gyp}:{target_name}#target"
+            new_target_list.append(new_target_name)
+
+            # Add to new_target_dicts.
+            new_target_dicts[new_target_name] = _TargetFromSpec(spec, params)
+
+            # Add to new_data.
+            for old_target in data[old_qualified_target.split(":")[0]]["targets"]:
+                if old_target["target_name"] == target_name:
+                    new_data_target = {}
+                    new_data_target["target_name"] = old_target["target_name"]
+                    new_data_target["toolset"] = old_target["toolset"]
+                    new_data[main_gyp]["targets"].append(new_data_target)
+
+    # Create sources target.
+    sources_target_name = "sources_for_indexing"
+    sources_target = _TargetFromSpec(
+        {
+            "target_name": sources_target_name,
+            "toolset": "target",
+            "default_configuration": "Default",
+            "mac_bundle": "0",
+            "type": "executable",
+        },
+        None,
+    )
+
+    # Tell Xcode to look everywhere for headers.
+    sources_target["configurations"] = {"Default": {"include_dirs": [depth]}}
+
+    # Put excluded files into the sources target so they can be opened in Xcode.
+    skip_excluded_files = not generator_flags.get(
+        "xcode_ninja_list_excluded_files", True
+    )
+
+    sources = []
+    for target, target_dict in target_dicts.items():
+        base = os.path.dirname(target)
+        files = target_dict.get("sources", []) + target_dict.get(
+            "mac_bundle_resources", []
+        )
+
+        if not skip_excluded_files:
+            files.extend(
+                target_dict.get("sources_excluded", [])
+                + target_dict.get("mac_bundle_resources_excluded", [])
+            )
+
+        for action in target_dict.get("actions", []):
+            files.extend(action.get("inputs", []))
+
+            if not skip_excluded_files:
+                files.extend(action.get("inputs_excluded", []))
+
+        # Remove files starting with $. These are mostly intermediate files for the
+        # build system.
+        files = [file for file in files if not file.startswith("$")]
+
+        # Make sources relative to root build file.
+        relative_path = os.path.dirname(main_gyp)
+        sources += [
+            os.path.relpath(os.path.join(base, file), relative_path) for file in files
+        ]
+
+    sources_target["sources"] = sorted(set(sources))
+
+    # Put sources_to_index in it's own gyp.
+    sources_gyp = os.path.join(os.path.dirname(main_gyp), sources_target_name + ".gyp")
+    fully_qualified_target_name = f"{sources_gyp}:{sources_target_name}#target"
+
+    # Add to new_target_list, new_target_dicts and new_data.
+    new_target_list.append(fully_qualified_target_name)
+    new_target_dicts[fully_qualified_target_name] = sources_target
+    new_data_target = {}
+    new_data_target["target_name"] = sources_target["target_name"]
+    new_data_target["_DEPTH"] = depth
+    new_data_target["toolset"] = "target"
+    new_data[sources_gyp] = {}
+    new_data[sources_gyp]["targets"] = []
+    new_data[sources_gyp]["included_files"] = []
+    new_data[sources_gyp]["xcode_settings"] = data[orig_gyp].get("xcode_settings", {})
+    new_data[sources_gyp]["targets"].append(new_data_target)
+
+    # Write workspace to file.
+    _WriteWorkspace(main_gyp, sources_gyp, params)
+    return (new_target_list, new_target_dicts, new_data)
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/xcodeproj_file.py b/server/node_modules/node-gyp/gyp/pylib/gyp/xcodeproj_file.py
new file mode 100644
index 0000000..076eea3
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/xcodeproj_file.py
@@ -0,0 +1,3197 @@
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Xcode project file generator.
+
+This module is both an Xcode project file generator and a documentation of the
+Xcode project file format.  Knowledge of the project file format was gained
+based on extensive experience with Xcode, and by making changes to projects in
+Xcode.app and observing the resultant changes in the associated project files.
+
+XCODE PROJECT FILES
+
+The generator targets the file format as written by Xcode 3.2 (specifically,
+3.2.6), but past experience has taught that the format has not changed
+significantly in the past several years, and future versions of Xcode are able
+to read older project files.
+
+Xcode project files are "bundled": the project "file" from an end-user's
+perspective is actually a directory with an ".xcodeproj" extension.  The
+project file from this module's perspective is actually a file inside this
+directory, always named "project.pbxproj".  This file contains a complete
+description of the project and is all that is needed to use the xcodeproj.
+Other files contained in the xcodeproj directory are simply used to store
+per-user settings, such as the state of various UI elements in the Xcode
+application.
+
+The project.pbxproj file is a property list, stored in a format almost
+identical to the NeXTstep property list format.  The file is able to carry
+Unicode data, and is encoded in UTF-8.  The root element in the property list
+is a dictionary that contains several properties of minimal interest, and two
+properties of immense interest.  The most important property is a dictionary
+named "objects".  The entire structure of the project is represented by the
+children of this property.  The objects dictionary is keyed by unique 96-bit
+values represented by 24 uppercase hexadecimal characters.  Each value in the
+objects dictionary is itself a dictionary, describing an individual object.
+
+Each object in the dictionary is a member of a class, which is identified by
+the "isa" property of each object.  A variety of classes are represented in a
+project file.  Objects can refer to other objects by ID, using the 24-character
+hexadecimal object key.  A project's objects form a tree, with a root object
+of class PBXProject at the root.  As an example, the PBXProject object serves
+as parent to an XCConfigurationList object defining the build configurations
+used in the project, a PBXGroup object serving as a container for all files
+referenced in the project, and a list of target objects, each of which defines
+a target in the project.  There are several different types of target object,
+such as PBXNativeTarget and PBXAggregateTarget.  In this module, this
+relationship is expressed by having each target type derive from an abstract
+base named XCTarget.
+
+The project.pbxproj file's root dictionary also contains a property, sibling to
+the "objects" dictionary, named "rootObject".  The value of rootObject is a
+24-character object key referring to the root PBXProject object in the
+objects dictionary.
+
+In Xcode, every file used as input to a target or produced as a final product
+of a target must appear somewhere in the hierarchy rooted at the PBXGroup
+object referenced by the PBXProject's mainGroup property.  A PBXGroup is
+generally represented as a folder in the Xcode application.  PBXGroups can
+contain other PBXGroups as well as PBXFileReferences, which are pointers to
+actual files.
+
+Each XCTarget contains a list of build phases, represented in this module by
+the abstract base XCBuildPhase.  Examples of concrete XCBuildPhase derivations
+are PBXSourcesBuildPhase and PBXFrameworksBuildPhase, which correspond to the
+"Compile Sources" and "Link Binary With Libraries" phases displayed in the
+Xcode application.  Files used as input to these phases (for example, source
+files in the former case and libraries and frameworks in the latter) are
+represented by PBXBuildFile objects, referenced by elements of "files" lists
+in XCTarget objects.  Each PBXBuildFile object refers to a PBXBuildFile
+object as a "weak" reference: it does not "own" the PBXBuildFile, which is
+owned by the root object's mainGroup or a descendant group.  In most cases, the
+layer of indirection between an XCBuildPhase and a PBXFileReference via a
+PBXBuildFile appears extraneous, but there's actually one reason for this:
+file-specific compiler flags are added to the PBXBuildFile object so as to
+allow a single file to be a member of multiple targets while having distinct
+compiler flags for each.  These flags can be modified in the Xcode applciation
+in the "Build" tab of a File Info window.
+
+When a project is open in the Xcode application, Xcode will rewrite it.  As
+such, this module is careful to adhere to the formatting used by Xcode, to
+avoid insignificant changes appearing in the file when it is used in the
+Xcode application.  This will keep version control repositories happy, and
+makes it possible to compare a project file used in Xcode to one generated by
+this module to determine if any significant changes were made in the
+application.
+
+Xcode has its own way of assigning 24-character identifiers to each object,
+which is not duplicated here.  Because the identifier only is only generated
+once, when an object is created, and is then left unchanged, there is no need
+to attempt to duplicate Xcode's behavior in this area.  The generator is free
+to select any identifier, even at random, to refer to the objects it creates,
+and Xcode will retain those identifiers and use them when subsequently
+rewriting the project file.  However, the generator would choose new random
+identifiers each time the project files are generated, leading to difficulties
+comparing "used" project files to "pristine" ones produced by this module,
+and causing the appearance of changes as every object identifier is changed
+when updated projects are checked in to a version control repository.  To
+mitigate this problem, this module chooses identifiers in a more deterministic
+way, by hashing a description of each object as well as its parent and ancestor
+objects.  This strategy should result in minimal "shift" in IDs as successive
+generations of project files are produced.
+
+THIS MODULE
+
+This module introduces several classes, all derived from the XCObject class.
+Nearly all of the "brains" are built into the XCObject class, which understands
+how to create and modify objects, maintain the proper tree structure, compute
+identifiers, and print objects.  For the most part, classes derived from
+XCObject need only provide a _schema class object, a dictionary that
+expresses what properties objects of the class may contain.
+
+Given this structure, it's possible to build a minimal project file by creating
+objects of the appropriate types and making the proper connections:
+
+  config_list = XCConfigurationList()
+  group = PBXGroup()
+  project = PBXProject({'buildConfigurationList': config_list,
+                        'mainGroup': group})
+
+With the project object set up, it can be added to an XCProjectFile object.
+XCProjectFile is a pseudo-class in the sense that it is a concrete XCObject
+subclass that does not actually correspond to a class type found in a project
+file.  Rather, it is used to represent the project file's root dictionary.
+Printing an XCProjectFile will print the entire project file, including the
+full "objects" dictionary.
+
+  project_file = XCProjectFile({'rootObject': project})
+  project_file.ComputeIDs()
+  project_file.Print()
+
+Xcode project files are always encoded in UTF-8.  This module will accept
+strings of either the str class or the unicode class.  Strings of class str
+are assumed to already be encoded in UTF-8.  Obviously, if you're just using
+ASCII, you won't encounter difficulties because ASCII is a UTF-8 subset.
+Strings of class unicode are handled properly and encoded in UTF-8 when
+a project file is output.
+"""
+
+import gyp.common
+from functools import cmp_to_key
+import hashlib
+from operator import attrgetter
+import posixpath
+import re
+import struct
+import sys
+
+
+def cmp(x, y):
+    return (x > y) - (x < y)
+
+
+# See XCObject._EncodeString.  This pattern is used to determine when a string
+# can be printed unquoted.  Strings that match this pattern may be printed
+# unquoted.  Strings that do not match must be quoted and may be further
+# transformed to be properly encoded.  Note that this expression matches the
+# characters listed with "+", for 1 or more occurrences: if a string is empty,
+# it must not match this pattern, because it needs to be encoded as "".
+_unquoted = re.compile("^[A-Za-z0-9$./_]+$")
+
+# Strings that match this pattern are quoted regardless of what _unquoted says.
+# Oddly, Xcode will quote any string with a run of three or more underscores.
+_quoted = re.compile("___")
+
+# This pattern should match any character that needs to be escaped by
+# XCObject._EncodeString.  See that function.
+_escaped = re.compile('[\\\\"]|[\x00-\x1f]')
+
+
+# Used by SourceTreeAndPathFromPath
+_path_leading_variable = re.compile(r"^\$$(.*?)$(/(.*))?$")
+
+
+def SourceTreeAndPathFromPath(input_path):
+    """Given input_path, returns a tuple with sourceTree and path values.
+
+  Examples:
+    input_path     (source_tree, output_path)
+    '$(VAR)/path'  ('VAR', 'path')
+    '$(VAR)'       ('VAR', None)
+    'path'         (None, 'path')
+  """
+
+    source_group_match = _path_leading_variable.match(input_path)
+    if source_group_match:
+        source_tree = source_group_match.group(1)
+        output_path = source_group_match.group(3)  # This may be None.
+    else:
+        source_tree = None
+        output_path = input_path
+
+    return (source_tree, output_path)
+
+
+def ConvertVariablesToShellSyntax(input_string):
+    return re.sub(r"\$$(.*?)$", "${\\1}", input_string)
+
+
+class XCObject:
+    """The abstract base of all class types used in Xcode project files.
+
+  Class variables:
+    _schema: A dictionary defining the properties of this class.  The keys to
+             _schema are string property keys as used in project files.  Values
+             are a list of four or five elements:
+             [ is_list, property_type, is_strong, is_required, default ]
+             is_list: True if the property described is a list, as opposed
+                      to a single element.
+             property_type: The type to use as the value of the property,
+                            or if is_list is True, the type to use for each
+                            element of the value's list.  property_type must
+                            be an XCObject subclass, or one of the built-in
+                            types str, int, or dict.
+             is_strong: If property_type is an XCObject subclass, is_strong
+                        is True to assert that this class "owns," or serves
+                        as parent, to the property value (or, if is_list is
+                        True, values).  is_strong must be False if
+                        property_type is not an XCObject subclass.
+             is_required: True if the property is required for the class.
+                          Note that is_required being True does not preclude
+                          an empty string ("", in the case of property_type
+                          str) or list ([], in the case of is_list True) from
+                          being set for the property.
+             default: Optional.  If is_required is True, default may be set
+                      to provide a default value for objects that do not supply
+                      their own value.  If is_required is True and default
+                      is not provided, users of the class must supply their own
+                      value for the property.
+             Note that although the values of the array are expressed in
+             boolean terms, subclasses provide values as integers to conserve
+             horizontal space.
+    _should_print_single_line: False in XCObject.  Subclasses whose objects
+                               should be written to the project file in the
+                               alternate single-line format, such as
+                               PBXFileReference and PBXBuildFile, should
+                               set this to True.
+    _encode_transforms: Used by _EncodeString to encode unprintable characters.
+                        The index into this list is the ordinal of the
+                        character to transform; each value is a string
+                        used to represent the character in the output.  XCObject
+                        provides an _encode_transforms list suitable for most
+                        XCObject subclasses.
+    _alternate_encode_transforms: Provided for subclasses that wish to use
+                                  the alternate encoding rules.  Xcode seems
+                                  to use these rules when printing objects in
+                                  single-line format.  Subclasses that desire
+                                  this behavior should set _encode_transforms
+                                  to _alternate_encode_transforms.
+    _hashables: A list of XCObject subclasses that can be hashed by ComputeIDs
+                to construct this object's ID.  Most classes that need custom
+                hashing behavior should do it by overriding Hashables,
+                but in some cases an object's parent may wish to push a
+                hashable value into its child, and it can do so by appending
+                to _hashables.
+  Attributes:
+    id: The object's identifier, a 24-character uppercase hexadecimal string.
+        Usually, objects being created should not set id until the entire
+        project file structure is built.  At that point, UpdateIDs() should
+        be called on the root object to assign deterministic values for id to
+        each object in the tree.
+    parent: The object's parent.  This is set by a parent XCObject when a child
+            object is added to it.
+    _properties: The object's property dictionary.  An object's properties are
+                 described by its class' _schema variable.
+  """
+
+    _schema = {}
+    _should_print_single_line = False
+
+    # See _EncodeString.
+    _encode_transforms = []
+    i = 0
+    while i < ord(" "):
+        _encode_transforms.append("\\U%04x" % i)
+        i = i + 1
+    _encode_transforms[7] = "\\a"
+    _encode_transforms[8] = "\\b"
+    _encode_transforms[9] = "\\t"
+    _encode_transforms[10] = "\\n"
+    _encode_transforms[11] = "\\v"
+    _encode_transforms[12] = "\\f"
+    _encode_transforms[13] = "\\n"
+
+    _alternate_encode_transforms = list(_encode_transforms)
+    _alternate_encode_transforms[9] = chr(9)
+    _alternate_encode_transforms[10] = chr(10)
+    _alternate_encode_transforms[11] = chr(11)
+
+    def __init__(self, properties=None, id=None, parent=None):
+        self.id = id
+        self.parent = parent
+        self._properties = {}
+        self._hashables = []
+        self._SetDefaultsFromSchema()
+        self.UpdateProperties(properties)
+
+    def __repr__(self):
+        try:
+            name = self.Name()
+        except NotImplementedError:
+            return f"<{self.__class__.__name__} at 0x{id(self):x}>"
+        return f"<{self.__class__.__name__} {name!r} at 0x{id(self):x}>"
+
+    def Copy(self):
+        """Make a copy of this object.
+
+    The new object will have its own copy of lists and dicts.  Any XCObject
+    objects owned by this object (marked "strong") will be copied in the
+    new object, even those found in lists.  If this object has any weak
+    references to other XCObjects, the same references are added to the new
+    object without making a copy.
+    """
+
+        that = self.__class__(id=self.id, parent=self.parent)
+        for key, value in self._properties.items():
+            is_strong = self._schema[key][2]
+
+            if isinstance(value, XCObject):
+                if is_strong:
+                    new_value = value.Copy()
+                    new_value.parent = that
+                    that._properties[key] = new_value
+                else:
+                    that._properties[key] = value
+            elif isinstance(value, (str, int)):
+                that._properties[key] = value
+            elif isinstance(value, list):
+                if is_strong:
+                    # If is_strong is True, each element is an XCObject, so it's safe to
+                    # call Copy.
+                    that._properties[key] = []
+                    for item in value:
+                        new_item = item.Copy()
+                        new_item.parent = that
+                        that._properties[key].append(new_item)
+                else:
+                    that._properties[key] = value[:]
+            elif isinstance(value, dict):
+                # dicts are never strong.
+                if is_strong:
+                    raise TypeError(
+                        "Strong dict for key " + key + " in " + self.__class__.__name__
+                    )
+                else:
+                    that._properties[key] = value.copy()
+            else:
+                raise TypeError(
+                    "Unexpected type "
+                    + value.__class__.__name__
+                    + " for key "
+                    + key
+                    + " in "
+                    + self.__class__.__name__
+                )
+
+        return that
+
+    def Name(self):
+        """Return the name corresponding to an object.
+
+    Not all objects necessarily need to be nameable, and not all that do have
+    a "name" property.  Override as needed.
+    """
+
+        # If the schema indicates that "name" is required, try to access the
+        # property even if it doesn't exist.  This will result in a KeyError
+        # being raised for the property that should be present, which seems more
+        # appropriate than NotImplementedError in this case.
+        if "name" in self._properties or (
+            "name" in self._schema and self._schema["name"][3]
+        ):
+            return self._properties["name"]
+
+        raise NotImplementedError(self.__class__.__name__ + " must implement Name")
+
+    def Comment(self):
+        """Return a comment string for the object.
+
+    Most objects just use their name as the comment, but PBXProject uses
+    different values.
+
+    The returned comment is not escaped and does not have any comment marker
+    strings applied to it.
+    """
+
+        return self.Name()
+
+    def Hashables(self):
+        hashables = [self.__class__.__name__]
+
+        name = self.Name()
+        if name is not None:
+            hashables.append(name)
+
+        hashables.extend(self._hashables)
+
+        return hashables
+
+    def HashablesForChild(self):
+        return None
+
+    def ComputeIDs(self, recursive=True, overwrite=True, seed_hash=None):
+        """Set "id" properties deterministically.
+
+    An object's "id" property is set based on a hash of its class type and
+    name, as well as the class type and name of all ancestor objects.  As
+    such, it is only advisable to call ComputeIDs once an entire project file
+    tree is built.
+
+    If recursive is True, recurse into all descendant objects and update their
+    hashes.
+
+    If overwrite is True, any existing value set in the "id" property will be
+    replaced.
+    """
+
+        def _HashUpdate(hash, data):
+            """Update hash with data's length and contents.
+
+      If the hash were updated only with the value of data, it would be
+      possible for clowns to induce collisions by manipulating the names of
+      their objects.  By adding the length, it's exceedingly less likely that
+      ID collisions will be encountered, intentionally or not.
+      """
+
+            hash.update(struct.pack(">i", len(data)))
+            if isinstance(data, str):
+                data = data.encode("utf-8")
+            hash.update(data)
+
+        if seed_hash is None:
+            seed_hash = hashlib.sha1()
+
+        hash = seed_hash.copy()
+
+        hashables = self.Hashables()
+        assert len(hashables) > 0
+        for hashable in hashables:
+            _HashUpdate(hash, hashable)
+
+        if recursive:
+            hashables_for_child = self.HashablesForChild()
+            if hashables_for_child is None:
+                child_hash = hash
+            else:
+                assert len(hashables_for_child) > 0
+                child_hash = seed_hash.copy()
+                for hashable in hashables_for_child:
+                    _HashUpdate(child_hash, hashable)
+
+            for child in self.Children():
+                child.ComputeIDs(recursive, overwrite, child_hash)
+
+        if overwrite or self.id is None:
+            # Xcode IDs are only 96 bits (24 hex characters), but a SHA-1 digest is
+            # is 160 bits.  Instead of throwing out 64 bits of the digest, xor them
+            # into the portion that gets used.
+            assert hash.digest_size % 4 == 0
+            digest_int_count = hash.digest_size // 4
+            digest_ints = struct.unpack(">" + "I" * digest_int_count, hash.digest())
+            id_ints = [0, 0, 0]
+            for index in range(0, digest_int_count):
+                id_ints[index % 3] ^= digest_ints[index]
+            self.id = "%08X%08X%08X" % tuple(id_ints)
+
+    def EnsureNoIDCollisions(self):
+        """Verifies that no two objects have the same ID.  Checks all descendants.
+    """
+
+        ids = {}
+        descendants = self.Descendants()
+        for descendant in descendants:
+            if descendant.id in ids:
+                other = ids[descendant.id]
+                raise KeyError(
+                    'Duplicate ID %s, objects "%s" and "%s" in "%s"'
+                    % (
+                        descendant.id,
+                        str(descendant._properties),
+                        str(other._properties),
+                        self._properties["rootObject"].Name(),
+                    )
+                )
+            ids[descendant.id] = descendant
+
+    def Children(self):
+        """Returns a list of all of this object's owned (strong) children."""
+
+        children = []
+        for property, attributes in self._schema.items():
+            (is_list, property_type, is_strong) = attributes[0:3]
+            if is_strong and property in self._properties:
+                if not is_list:
+                    children.append(self._properties[property])
+                else:
+                    children.extend(self._properties[property])
+        return children
+
+    def Descendants(self):
+        """Returns a list of all of this object's descendants, including this
+    object.
+    """
+
+        children = self.Children()
+        descendants = [self]
+        for child in children:
+            descendants.extend(child.Descendants())
+        return descendants
+
+    def PBXProjectAncestor(self):
+        # The base case for recursion is defined at PBXProject.PBXProjectAncestor.
+        if self.parent:
+            return self.parent.PBXProjectAncestor()
+        return None
+
+    def _EncodeComment(self, comment):
+        """Encodes a comment to be placed in the project file output, mimicking
+    Xcode behavior.
+    """
+
+        # This mimics Xcode behavior by wrapping the comment in "/*" and "*/".  If
+        # the string already contains a "*/", it is turned into "(*)/".  This keeps
+        # the file writer from outputting something that would be treated as the
+        # end of a comment in the middle of something intended to be entirely a
+        # comment.
+
+        return "/* " + comment.replace("*/", "(*)/") + " */"
+
+    def _EncodeTransform(self, match):
+        # This function works closely with _EncodeString.  It will only be called
+        # by re.sub with match.group(0) containing a character matched by the
+        # the _escaped expression.
+        char = match.group(0)
+
+        # Backslashes (\) and quotation marks (") are always replaced with a
+        # backslash-escaped version of the same.  Everything else gets its
+        # replacement from the class' _encode_transforms array.
+        if char == "\\":
+            return "\\\\"
+        if char == '"':
+            return '\\"'
+        return self._encode_transforms[ord(char)]
+
+    def _EncodeString(self, value):
+        """Encodes a string to be placed in the project file output, mimicking
+    Xcode behavior.
+    """
+
+        # Use quotation marks when any character outside of the range A-Z, a-z, 0-9,
+        # $ (dollar sign), . (period), and _ (underscore) is present.  Also use
+        # quotation marks to represent empty strings.
+        #
+        # Escape " (double-quote) and \ (backslash) by preceding them with a
+        # backslash.
+        #
+        # Some characters below the printable ASCII range are encoded specially:
+        #     7 ^G BEL is encoded as "\a"
+        #     8 ^H BS  is encoded as "\b"
+        #    11 ^K VT  is encoded as "\v"
+        #    12 ^L NP  is encoded as "\f"
+        #   127 ^? DEL is passed through as-is without escaping
+        #  - In PBXFileReference and PBXBuildFile objects:
+        #     9 ^I HT  is passed through as-is without escaping
+        #    10 ^J NL  is passed through as-is without escaping
+        #    13 ^M CR  is passed through as-is without escaping
+        #  - In other objects:
+        #     9 ^I HT  is encoded as "\t"
+        #    10 ^J NL  is encoded as "\n"
+        #    13 ^M CR  is encoded as "\n" rendering it indistinguishable from
+        #              10 ^J NL
+        # All other characters within the ASCII control character range (0 through
+        # 31 inclusive) are encoded as "\U001f" referring to the Unicode code point
+        # in hexadecimal.  For example, character 14 (^N SO) is encoded as "\U000e".
+        # Characters above the ASCII range are passed through to the output encoded
+        # as UTF-8 without any escaping.  These mappings are contained in the
+        # class' _encode_transforms list.
+
+        if _unquoted.search(value) and not _quoted.search(value):
+            return value
+
+        return '"' + _escaped.sub(self._EncodeTransform, value) + '"'
+
+    def _XCPrint(self, file, tabs, line):
+        file.write("\t" * tabs + line)
+
+    def _XCPrintableValue(self, tabs, value, flatten_list=False):
+        """Returns a representation of value that may be printed in a project file,
+    mimicking Xcode's behavior.
+
+    _XCPrintableValue can handle str and int values, XCObjects (which are
+    made printable by returning their id property), and list and dict objects
+    composed of any of the above types.  When printing a list or dict, and
+    _should_print_single_line is False, the tabs parameter is used to determine
+    how much to indent the lines corresponding to the items in the list or
+    dict.
+
+    If flatten_list is True, single-element lists will be transformed into
+    strings.
+    """
+
+        printable = ""
+        comment = None
+
+        if self._should_print_single_line:
+            sep = " "
+            element_tabs = ""
+            end_tabs = ""
+        else:
+            sep = "\n"
+            element_tabs = "\t" * (tabs + 1)
+            end_tabs = "\t" * tabs
+
+        if isinstance(value, XCObject):
+            printable += value.id
+            comment = value.Comment()
+        elif isinstance(value, str):
+            printable += self._EncodeString(value)
+        elif isinstance(value, str):
+            printable += self._EncodeString(value.encode("utf-8"))
+        elif isinstance(value, int):
+            printable += str(value)
+        elif isinstance(value, list):
+            if flatten_list and len(value) <= 1:
+                if len(value) == 0:
+                    printable += self._EncodeString("")
+                else:
+                    printable += self._EncodeString(value[0])
+            else:
+                printable = "(" + sep
+                for item in value:
+                    printable += (
+                        element_tabs
+                        + self._XCPrintableValue(tabs + 1, item, flatten_list)
+                        + ","
+                        + sep
+                    )
+                printable += end_tabs + ")"
+        elif isinstance(value, dict):
+            printable = "{" + sep
+            for item_key, item_value in sorted(value.items()):
+                printable += (
+                    element_tabs
+                    + self._XCPrintableValue(tabs + 1, item_key, flatten_list)
+                    + " = "
+                    + self._XCPrintableValue(tabs + 1, item_value, flatten_list)
+                    + ";"
+                    + sep
+                )
+            printable += end_tabs + "}"
+        else:
+            raise TypeError("Can't make " + value.__class__.__name__ + " printable")
+
+        if comment:
+            printable += " " + self._EncodeComment(comment)
+
+        return printable
+
+    def _XCKVPrint(self, file, tabs, key, value):
+        """Prints a key and value, members of an XCObject's _properties dictionary,
+    to file.
+
+    tabs is an int identifying the indentation level.  If the class'
+    _should_print_single_line variable is True, tabs is ignored and the
+    key-value pair will be followed by a space insead of a newline.
+    """
+
+        if self._should_print_single_line:
+            printable = ""
+            after_kv = " "
+        else:
+            printable = "\t" * tabs
+            after_kv = "\n"
+
+        # Xcode usually prints remoteGlobalIDString values in PBXContainerItemProxy
+        # objects without comments.  Sometimes it prints them with comments, but
+        # the majority of the time, it doesn't.  To avoid unnecessary changes to
+        # the project file after Xcode opens it, don't write comments for
+        # remoteGlobalIDString.  This is a sucky hack and it would certainly be
+        # cleaner to extend the schema to indicate whether or not a comment should
+        # be printed, but since this is the only case where the problem occurs and
+        # Xcode itself can't seem to make up its mind, the hack will suffice.
+        #
+        # Also see PBXContainerItemProxy._schema['remoteGlobalIDString'].
+        if key == "remoteGlobalIDString" and isinstance(self, PBXContainerItemProxy):
+            value_to_print = value.id
+        else:
+            value_to_print = value
+
+        # PBXBuildFile's settings property is represented in the output as a dict,
+        # but a hack here has it represented as a string. Arrange to strip off the
+        # quotes so that it shows up in the output as expected.
+        if key == "settings" and isinstance(self, PBXBuildFile):
+            strip_value_quotes = True
+        else:
+            strip_value_quotes = False
+
+        # In another one-off, let's set flatten_list on buildSettings properties
+        # of XCBuildConfiguration objects, because that's how Xcode treats them.
+        if key == "buildSettings" and isinstance(self, XCBuildConfiguration):
+            flatten_list = True
+        else:
+            flatten_list = False
+
+        try:
+            printable_key = self._XCPrintableValue(tabs, key, flatten_list)
+            printable_value = self._XCPrintableValue(tabs, value_to_print, flatten_list)
+            if (
+                strip_value_quotes
+                and len(printable_value) > 1
+                and printable_value[0] == '"'
+                and printable_value[-1] == '"'
+            ):
+                printable_value = printable_value[1:-1]
+            printable += printable_key + " = " + printable_value + ";" + after_kv
+        except TypeError as e:
+            gyp.common.ExceptionAppend(e, 'while printing key "%s"' % key)
+            raise
+
+        self._XCPrint(file, 0, printable)
+
+    def Print(self, file=sys.stdout):
+        """Prints a reprentation of this object to file, adhering to Xcode output
+    formatting.
+    """
+
+        self.VerifyHasRequiredProperties()
+
+        if self._should_print_single_line:
+            # When printing an object in a single line, Xcode doesn't put any space
+            # between the beginning of a dictionary (or presumably a list) and the
+            # first contained item, so you wind up with snippets like
+            #   ...CDEF = {isa = PBXFileReference; fileRef = 0123...
+            # If it were me, I would have put a space in there after the opening
+            # curly, but I guess this is just another one of those inconsistencies
+            # between how Xcode prints PBXFileReference and PBXBuildFile objects as
+            # compared to other objects.  Mimic Xcode's behavior here by using an
+            # empty string for sep.
+            sep = ""
+            end_tabs = 0
+        else:
+            sep = "\n"
+            end_tabs = 2
+
+        # Start the object.  For example, '\t\tPBXProject = {\n'.
+        self._XCPrint(file, 2, self._XCPrintableValue(2, self) + " = {" + sep)
+
+        # "isa" isn't in the _properties dictionary, it's an intrinsic property
+        # of the class which the object belongs to.  Xcode always outputs "isa"
+        # as the first element of an object dictionary.
+        self._XCKVPrint(file, 3, "isa", self.__class__.__name__)
+
+        # The remaining elements of an object dictionary are sorted alphabetically.
+        for property, value in sorted(self._properties.items()):
+            self._XCKVPrint(file, 3, property, value)
+
+        # End the object.
+        self._XCPrint(file, end_tabs, "};\n")
+
+    def UpdateProperties(self, properties, do_copy=False):
+        """Merge the supplied properties into the _properties dictionary.
+
+    The input properties must adhere to the class schema or a KeyError or
+    TypeError exception will be raised.  If adding an object of an XCObject
+    subclass and the schema indicates a strong relationship, the object's
+    parent will be set to this object.
+
+    If do_copy is True, then lists, dicts, strong-owned XCObjects, and
+    strong-owned XCObjects in lists will be copied instead of having their
+    references added.
+    """
+
+        if properties is None:
+            return
+
+        for property, value in properties.items():
+            # Make sure the property is in the schema.
+            if property not in self._schema:
+                raise KeyError(property + " not in " + self.__class__.__name__)
+
+            # Make sure the property conforms to the schema.
+            (is_list, property_type, is_strong) = self._schema[property][0:3]
+            if is_list:
+                if value.__class__ != list:
+                    raise TypeError(
+                        property
+                        + " of "
+                        + self.__class__.__name__
+                        + " must be list, not "
+                        + value.__class__.__name__
+                    )
+                for item in value:
+                    if not isinstance(item, property_type) and not (
+                        isinstance(item, str) and property_type == str
+                    ):
+                        # Accept unicode where str is specified.  str is treated as
+                        # UTF-8-encoded.
+                        raise TypeError(
+                            "item of "
+                            + property
+                            + " of "
+                            + self.__class__.__name__
+                            + " must be "
+                            + property_type.__name__
+                            + ", not "
+                            + item.__class__.__name__
+                        )
+            elif not isinstance(value, property_type) and not (
+                isinstance(value, str) and property_type == str
+            ):
+                # Accept unicode where str is specified.  str is treated as
+                # UTF-8-encoded.
+                raise TypeError(
+                    property
+                    + " of "
+                    + self.__class__.__name__
+                    + " must be "
+                    + property_type.__name__
+                    + ", not "
+                    + value.__class__.__name__
+                )
+
+            # Checks passed, perform the assignment.
+            if do_copy:
+                if isinstance(value, XCObject):
+                    if is_strong:
+                        self._properties[property] = value.Copy()
+                    else:
+                        self._properties[property] = value
+                elif isinstance(value, (str, int)):
+                    self._properties[property] = value
+                elif isinstance(value, list):
+                    if is_strong:
+                        # If is_strong is True, each element is an XCObject,
+                        # so it's safe to call Copy.
+                        self._properties[property] = []
+                        for item in value:
+                            self._properties[property].append(item.Copy())
+                    else:
+                        self._properties[property] = value[:]
+                elif isinstance(value, dict):
+                    self._properties[property] = value.copy()
+                else:
+                    raise TypeError(
+                        "Don't know how to copy a "
+                        + value.__class__.__name__
+                        + " object for "
+                        + property
+                        + " in "
+                        + self.__class__.__name__
+                    )
+            else:
+                self._properties[property] = value
+
+            # Set up the child's back-reference to this object.  Don't use |value|
+            # any more because it may not be right if do_copy is true.
+            if is_strong:
+                if not is_list:
+                    self._properties[property].parent = self
+                else:
+                    for item in self._properties[property]:
+                        item.parent = self
+
+    def HasProperty(self, key):
+        return key in self._properties
+
+    def GetProperty(self, key):
+        return self._properties[key]
+
+    def SetProperty(self, key, value):
+        self.UpdateProperties({key: value})
+
+    def DelProperty(self, key):
+        if key in self._properties:
+            del self._properties[key]
+
+    def AppendProperty(self, key, value):
+        # TODO(mark): Support ExtendProperty too (and make this call that)?
+
+        # Schema validation.
+        if key not in self._schema:
+            raise KeyError(key + " not in " + self.__class__.__name__)
+
+        (is_list, property_type, is_strong) = self._schema[key][0:3]
+        if not is_list:
+            raise TypeError(key + " of " + self.__class__.__name__ + " must be list")
+        if not isinstance(value, property_type):
+            raise TypeError(
+                "item of "
+                + key
+                + " of "
+                + self.__class__.__name__
+                + " must be "
+                + property_type.__name__
+                + ", not "
+                + value.__class__.__name__
+            )
+
+        # If the property doesn't exist yet, create a new empty list to receive the
+        # item.
+        self._properties[key] = self._properties.get(key, [])
+
+        # Set up the ownership link.
+        if is_strong:
+            value.parent = self
+
+        # Store the item.
+        self._properties[key].append(value)
+
+    def VerifyHasRequiredProperties(self):
+        """Ensure that all properties identified as required by the schema are
+    set.
+    """
+
+        # TODO(mark): A stronger verification mechanism is needed.  Some
+        # subclasses need to perform validation beyond what the schema can enforce.
+        for property, attributes in self._schema.items():
+            (is_list, property_type, is_strong, is_required) = attributes[0:4]
+            if is_required and property not in self._properties:
+                raise KeyError(self.__class__.__name__ + " requires " + property)
+
+    def _SetDefaultsFromSchema(self):
+        """Assign object default values according to the schema.  This will not
+    overwrite properties that have already been set."""
+
+        defaults = {}
+        for property, attributes in self._schema.items():
+            (is_list, property_type, is_strong, is_required) = attributes[0:4]
+            if (
+                is_required
+                and len(attributes) >= 5
+                and property not in self._properties
+            ):
+                default = attributes[4]
+
+                defaults[property] = default
+
+        if len(defaults) > 0:
+            # Use do_copy=True so that each new object gets its own copy of strong
+            # objects, lists, and dicts.
+            self.UpdateProperties(defaults, do_copy=True)
+
+
+class XCHierarchicalElement(XCObject):
+    """Abstract base for PBXGroup and PBXFileReference.  Not represented in a
+  project file."""
+
+    # TODO(mark): Do name and path belong here?  Probably so.
+    # If path is set and name is not, name may have a default value.  Name will
+    # be set to the basename of path, if the basename of path is different from
+    # the full value of path.  If path is already just a leaf name, name will
+    # not be set.
+    _schema = XCObject._schema.copy()
+    _schema.update(
+        {
+            "comments": [0, str, 0, 0],
+            "fileEncoding": [0, str, 0, 0],
+            "includeInIndex": [0, int, 0, 0],
+            "indentWidth": [0, int, 0, 0],
+            "lineEnding": [0, int, 0, 0],
+            "sourceTree": [0, str, 0, 1, "<group>"],
+            "tabWidth": [0, int, 0, 0],
+            "usesTabs": [0, int, 0, 0],
+            "wrapsLines": [0, int, 0, 0],
+        }
+    )
+
+    def __init__(self, properties=None, id=None, parent=None):
+        # super
+        XCObject.__init__(self, properties, id, parent)
+        if "path" in self._properties and "name" not in self._properties:
+            path = self._properties["path"]
+            name = posixpath.basename(path)
+            if name != "" and path != name:
+                self.SetProperty("name", name)
+
+        if "path" in self._properties and (
+            "sourceTree" not in self._properties
+            or self._properties["sourceTree"] == "<group>"
+        ):
+            # If the pathname begins with an Xcode variable like "$(SDKROOT)/", take
+            # the variable out and make the path be relative to that variable by
+            # assigning the variable name as the sourceTree.
+            (source_tree, path) = SourceTreeAndPathFromPath(self._properties["path"])
+            if source_tree is not None:
+                self._properties["sourceTree"] = source_tree
+            if path is not None:
+                self._properties["path"] = path
+            if (
+                source_tree is not None
+                and path is None
+                and "name" not in self._properties
+            ):
+                # The path was of the form "$(SDKROOT)" with no path following it.
+                # This object is now relative to that variable, so it has no path
+                # attribute of its own.  It does, however, keep a name.
+                del self._properties["path"]
+                self._properties["name"] = source_tree
+
+    def Name(self):
+        if "name" in self._properties:
+            return self._properties["name"]
+        elif "path" in self._properties:
+            return self._properties["path"]
+        else:
+            # This happens in the case of the root PBXGroup.
+            return None
+
+    def Hashables(self):
+        """Custom hashables for XCHierarchicalElements.
+
+    XCHierarchicalElements are special.  Generally, their hashes shouldn't
+    change if the paths don't change.  The normal XCObject implementation of
+    Hashables adds a hashable for each object, which means that if
+    the hierarchical structure changes (possibly due to changes caused when
+    TakeOverOnlyChild runs and encounters slight changes in the hierarchy),
+    the hashes will change.  For example, if a project file initially contains
+    a/b/f1 and a/b becomes collapsed into a/b, f1 will have a single parent
+    a/b.  If someone later adds a/f2 to the project file, a/b can no longer be
+    collapsed, and f1 winds up with parent b and grandparent a.  That would
+    be sufficient to change f1's hash.
+
+    To counteract this problem, hashables for all XCHierarchicalElements except
+    for the main group (which has neither a name nor a path) are taken to be
+    just the set of path components.  Because hashables are inherited from
+    parents, this provides assurance that a/b/f1 has the same set of hashables
+    whether its parent is b or a/b.
+
+    The main group is a special case.  As it is permitted to have no name or
+    path, it is permitted to use the standard XCObject hash mechanism.  This
+    is not considered a problem because there can be only one main group.
+    """
+
+        if self == self.PBXProjectAncestor()._properties["mainGroup"]:
+            # super
+            return XCObject.Hashables(self)
+
+        hashables = []
+
+        # Put the name in first, ensuring that if TakeOverOnlyChild collapses
+        # children into a top-level group like "Source", the name always goes
+        # into the list of hashables without interfering with path components.
+        if "name" in self._properties:
+            # Make it less likely for people to manipulate hashes by following the
+            # pattern of always pushing an object type value onto the list first.
+            hashables.append(self.__class__.__name__ + ".name")
+            hashables.append(self._properties["name"])
+
+        # NOTE: This still has the problem that if an absolute path is encountered,
+        # including paths with a sourceTree, they'll still inherit their parents'
+        # hashables, even though the paths aren't relative to their parents.  This
+        # is not expected to be much of a problem in practice.
+        path = self.PathFromSourceTreeAndPath()
+        if path is not None:
+            components = path.split(posixpath.sep)
+            for component in components:
+                hashables.append(self.__class__.__name__ + ".path")
+                hashables.append(component)
+
+        hashables.extend(self._hashables)
+
+        return hashables
+
+    def Compare(self, other):
+        # Allow comparison of these types.  PBXGroup has the highest sort rank;
+        # PBXVariantGroup is treated as equal to PBXFileReference.
+        valid_class_types = {
+            PBXFileReference: "file",
+            PBXGroup: "group",
+            PBXVariantGroup: "file",
+        }
+        self_type = valid_class_types[self.__class__]
+        other_type = valid_class_types[other.__class__]
+
+        if self_type == other_type:
+            # If the two objects are of the same sort rank, compare their names.
+            return cmp(self.Name(), other.Name())
+
+        # Otherwise, sort groups before everything else.
+        if self_type == "group":
+            return -1
+        return 1
+
+    def CompareRootGroup(self, other):
+        # This function should be used only to compare direct children of the
+        # containing PBXProject's mainGroup.  These groups should appear in the
+        # listed order.
+        # TODO(mark): "Build" is used by gyp.generator.xcode, perhaps the
+        # generator should have a way of influencing this list rather than having
+        # to hardcode for the generator here.
+        order = [
+            "Source",
+            "Intermediates",
+            "Projects",
+            "Frameworks",
+            "Products",
+            "Build",
+        ]
+
+        # If the groups aren't in the listed order, do a name comparison.
+        # Otherwise, groups in the listed order should come before those that
+        # aren't.
+        self_name = self.Name()
+        other_name = other.Name()
+        self_in = isinstance(self, PBXGroup) and self_name in order
+        other_in = isinstance(self, PBXGroup) and other_name in order
+        if not self_in and not other_in:
+            return self.Compare(other)
+        if self_name in order and other_name not in order:
+            return -1
+        if other_name in order and self_name not in order:
+            return 1
+
+        # If both groups are in the listed order, go by the defined order.
+        self_index = order.index(self_name)
+        other_index = order.index(other_name)
+        if self_index < other_index:
+            return -1
+        if self_index > other_index:
+            return 1
+        return 0
+
+    def PathFromSourceTreeAndPath(self):
+        # Turn the object's sourceTree and path properties into a single flat
+        # string of a form comparable to the path parameter.  If there's a
+        # sourceTree property other than "<group>", wrap it in $(...) for the
+        # comparison.
+        components = []
+        if self._properties["sourceTree"] != "<group>":
+            components.append("$(" + self._properties["sourceTree"] + ")")
+        if "path" in self._properties:
+            components.append(self._properties["path"])
+
+        if len(components) > 0:
+            return posixpath.join(*components)
+
+        return None
+
+    def FullPath(self):
+        # Returns a full path to self relative to the project file, or relative
+        # to some other source tree.  Start with self, and walk up the chain of
+        # parents prepending their paths, if any, until no more parents are
+        # available (project-relative path) or until a path relative to some
+        # source tree is found.
+        xche = self
+        path = None
+        while isinstance(xche, XCHierarchicalElement) and (
+            path is None or (not path.startswith("/") and not path.startswith("$"))
+        ):
+            this_path = xche.PathFromSourceTreeAndPath()
+            if this_path is not None and path is not None:
+                path = posixpath.join(this_path, path)
+            elif this_path is not None:
+                path = this_path
+            xche = xche.parent
+
+        return path
+
+
+class PBXGroup(XCHierarchicalElement):
+    """
+  Attributes:
+    _children_by_path: Maps pathnames of children of this PBXGroup to the
+      actual child XCHierarchicalElement objects.
+    _variant_children_by_name_and_path: Maps (name, path) tuples of
+      PBXVariantGroup children to the actual child PBXVariantGroup objects.
+  """
+
+    _schema = XCHierarchicalElement._schema.copy()
+    _schema.update(
+        {
+            "children": [1, XCHierarchicalElement, 1, 1, []],
+            "name": [0, str, 0, 0],
+            "path": [0, str, 0, 0],
+        }
+    )
+
+    def __init__(self, properties=None, id=None, parent=None):
+        # super
+        XCHierarchicalElement.__init__(self, properties, id, parent)
+        self._children_by_path = {}
+        self._variant_children_by_name_and_path = {}
+        for child in self._properties.get("children", []):
+            self._AddChildToDicts(child)
+
+    def Hashables(self):
+        # super
+        hashables = XCHierarchicalElement.Hashables(self)
+
+        # It is not sufficient to just rely on name and parent to build a unique
+        # hashable : a node could have two child PBXGroup sharing a common name.
+        # To add entropy the hashable is enhanced with the names of all its
+        # children.
+        for child in self._properties.get("children", []):
+            child_name = child.Name()
+            if child_name is not None:
+                hashables.append(child_name)
+
+        return hashables
+
+    def HashablesForChild(self):
+        # To avoid a circular reference the hashables used to compute a child id do
+        # not include the child names.
+        return XCHierarchicalElement.Hashables(self)
+
+    def _AddChildToDicts(self, child):
+        # Sets up this PBXGroup object's dicts to reference the child properly.
+        child_path = child.PathFromSourceTreeAndPath()
+        if child_path:
+            if child_path in self._children_by_path:
+                raise ValueError("Found multiple children with path " + child_path)
+            self._children_by_path[child_path] = child
+
+        if isinstance(child, PBXVariantGroup):
+            child_name = child._properties.get("name", None)
+            key = (child_name, child_path)
+            if key in self._variant_children_by_name_and_path:
+                raise ValueError(
+                    "Found multiple PBXVariantGroup children with "
+                    + "name "
+                    + str(child_name)
+                    + " and path "
+                    + str(child_path)
+                )
+            self._variant_children_by_name_and_path[key] = child
+
+    def AppendChild(self, child):
+        # Callers should use this instead of calling
+        # AppendProperty('children', child) directly because this function
+        # maintains the group's dicts.
+        self.AppendProperty("children", child)
+        self._AddChildToDicts(child)
+
+    def GetChildByName(self, name):
+        # This is not currently optimized with a dict as GetChildByPath is because
+        # it has few callers.  Most callers probably want GetChildByPath.  This
+        # function is only useful to get children that have names but no paths,
+        # which is rare.  The children of the main group ("Source", "Products",
+        # etc.) is pretty much the only case where this likely to come up.
+        #
+        # TODO(mark): Maybe this should raise an error if more than one child is
+        # present with the same name.
+        if "children" not in self._properties:
+            return None
+
+        for child in self._properties["children"]:
+            if child.Name() == name:
+                return child
+
+        return None
+
+    def GetChildByPath(self, path):
+        if not path:
+            return None
+
+        if path in self._children_by_path:
+            return self._children_by_path[path]
+
+        return None
+
+    def GetChildByRemoteObject(self, remote_object):
+        # This method is a little bit esoteric.  Given a remote_object, which
+        # should be a PBXFileReference in another project file, this method will
+        # return this group's PBXReferenceProxy object serving as a local proxy
+        # for the remote PBXFileReference.
+        #
+        # This function might benefit from a dict optimization as GetChildByPath
+        # for some workloads, but profiling shows that it's not currently a
+        # problem.
+        if "children" not in self._properties:
+            return None
+
+        for child in self._properties["children"]:
+            if not isinstance(child, PBXReferenceProxy):
+                continue
+
+            container_proxy = child._properties["remoteRef"]
+            if container_proxy._properties["remoteGlobalIDString"] == remote_object:
+                return child
+
+        return None
+
+    def AddOrGetFileByPath(self, path, hierarchical):
+        """Returns an existing or new file reference corresponding to path.
+
+    If hierarchical is True, this method will create or use the necessary
+    hierarchical group structure corresponding to path.  Otherwise, it will
+    look in and create an item in the current group only.
+
+    If an existing matching reference is found, it is returned, otherwise, a
+    new one will be created, added to the correct group, and returned.
+
+    If path identifies a directory by virtue of carrying a trailing slash,
+    this method returns a PBXFileReference of "folder" type.  If path
+    identifies a variant, by virtue of it identifying a file inside a directory
+    with an ".lproj" extension, this method returns a PBXVariantGroup
+    containing the variant named by path, and possibly other variants.  For
+    all other paths, a "normal" PBXFileReference will be returned.
+    """
+
+        # Adding or getting a directory?  Directories end with a trailing slash.
+        is_dir = False
+        if path.endswith("/"):
+            is_dir = True
+        path = posixpath.normpath(path)
+        if is_dir:
+            path = path + "/"
+
+        # Adding or getting a variant?  Variants are files inside directories
+        # with an ".lproj" extension.  Xcode uses variants for localization.  For
+        # a variant path/to/Language.lproj/MainMenu.nib, put a variant group named
+        # MainMenu.nib inside path/to, and give it a variant named Language.  In
+        # this example, grandparent would be set to path/to and parent_root would
+        # be set to Language.
+        variant_name = None
+        parent = posixpath.dirname(path)
+        grandparent = posixpath.dirname(parent)
+        parent_basename = posixpath.basename(parent)
+        (parent_root, parent_ext) = posixpath.splitext(parent_basename)
+        if parent_ext == ".lproj":
+            variant_name = parent_root
+        if grandparent == "":
+            grandparent = None
+
+        # Putting a directory inside a variant group is not currently supported.
+        assert not is_dir or variant_name is None
+
+        path_split = path.split(posixpath.sep)
+        if (
+            len(path_split) == 1
+            or ((is_dir or variant_name is not None) and len(path_split) == 2)
+            or not hierarchical
+        ):
+            # The PBXFileReference or PBXVariantGroup will be added to or gotten from
+            # this PBXGroup, no recursion necessary.
+            if variant_name is None:
+                # Add or get a PBXFileReference.
+                file_ref = self.GetChildByPath(path)
+                if file_ref is not None:
+                    assert file_ref.__class__ == PBXFileReference
+                else:
+                    file_ref = PBXFileReference({"path": path})
+                    self.AppendChild(file_ref)
+            else:
+                # Add or get a PBXVariantGroup.  The variant group name is the same
+                # as the basename (MainMenu.nib in the example above).  grandparent
+                # specifies the path to the variant group itself, and path_split[-2:]
+                # is the path of the specific variant relative to its group.
+                variant_group_name = posixpath.basename(path)
+                variant_group_ref = self.AddOrGetVariantGroupByNameAndPath(
+                    variant_group_name, grandparent
+                )
+                variant_path = posixpath.sep.join(path_split[-2:])
+                variant_ref = variant_group_ref.GetChildByPath(variant_path)
+                if variant_ref is not None:
+                    assert variant_ref.__class__ == PBXFileReference
+                else:
+                    variant_ref = PBXFileReference(
+                        {"name": variant_name, "path": variant_path}
+                    )
+                    variant_group_ref.AppendChild(variant_ref)
+                # The caller is interested in the variant group, not the specific
+                # variant file.
+                file_ref = variant_group_ref
+            return file_ref
+        else:
+            # Hierarchical recursion.  Add or get a PBXGroup corresponding to the
+            # outermost path component, and then recurse into it, chopping off that
+            # path component.
+            next_dir = path_split[0]
+            group_ref = self.GetChildByPath(next_dir)
+            if group_ref is not None:
+                assert group_ref.__class__ == PBXGroup
+            else:
+                group_ref = PBXGroup({"path": next_dir})
+                self.AppendChild(group_ref)
+            return group_ref.AddOrGetFileByPath(
+                posixpath.sep.join(path_split[1:]), hierarchical
+            )
+
+    def AddOrGetVariantGroupByNameAndPath(self, name, path):
+        """Returns an existing or new PBXVariantGroup for name and path.
+
+    If a PBXVariantGroup identified by the name and path arguments is already
+    present as a child of this object, it is returned.  Otherwise, a new
+    PBXVariantGroup with the correct properties is created, added as a child,
+    and returned.
+
+    This method will generally be called by AddOrGetFileByPath, which knows
+    when to create a variant group based on the structure of the pathnames
+    passed to it.
+    """
+
+        key = (name, path)
+        if key in self._variant_children_by_name_and_path:
+            variant_group_ref = self._variant_children_by_name_and_path[key]
+            assert variant_group_ref.__class__ == PBXVariantGroup
+            return variant_group_ref
+
+        variant_group_properties = {"name": name}
+        if path is not None:
+            variant_group_properties["path"] = path
+        variant_group_ref = PBXVariantGroup(variant_group_properties)
+        self.AppendChild(variant_group_ref)
+
+        return variant_group_ref
+
+    def TakeOverOnlyChild(self, recurse=False):
+        """If this PBXGroup has only one child and it's also a PBXGroup, take
+    it over by making all of its children this object's children.
+
+    This function will continue to take over only children when those children
+    are groups.  If there are three PBXGroups representing a, b, and c, with
+    c inside b and b inside a, and a and b have no other children, this will
+    result in a taking over both b and c, forming a PBXGroup for a/b/c.
+
+    If recurse is True, this function will recurse into children and ask them
+    to collapse themselves by taking over only children as well.  Assuming
+    an example hierarchy with files at a/b/c/d1, a/b/c/d2, and a/b/c/d3/e/f
+    (d1, d2, and f are files, the rest are groups), recursion will result in
+    a group for a/b/c containing a group for d3/e.
+    """
+
+        # At this stage, check that child class types are PBXGroup exactly,
+        # instead of using isinstance.  The only subclass of PBXGroup,
+        # PBXVariantGroup, should not participate in reparenting in the same way:
+        # reparenting by merging different object types would be wrong.
+        while (
+            len(self._properties["children"]) == 1
+            and self._properties["children"][0].__class__ == PBXGroup
+        ):
+            # Loop to take over the innermost only-child group possible.
+
+            child = self._properties["children"][0]
+
+            # Assume the child's properties, including its children.  Save a copy
+            # of this object's old properties, because they'll still be needed.
+            # This object retains its existing id and parent attributes.
+            old_properties = self._properties
+            self._properties = child._properties
+            self._children_by_path = child._children_by_path
+
+            if (
+                "sourceTree" not in self._properties
+                or self._properties["sourceTree"] == "<group>"
+            ):
+                # The child was relative to its parent.  Fix up the path.  Note that
+                # children with a sourceTree other than "<group>" are not relative to
+                # their parents, so no path fix-up is needed in that case.
+                if "path" in old_properties:
+                    if "path" in self._properties:
+                        # Both the original parent and child have paths set.
+                        self._properties["path"] = posixpath.join(
+                            old_properties["path"], self._properties["path"]
+                        )
+                    else:
+                        # Only the original parent has a path, use it.
+                        self._properties["path"] = old_properties["path"]
+                if "sourceTree" in old_properties:
+                    # The original parent had a sourceTree set, use it.
+                    self._properties["sourceTree"] = old_properties["sourceTree"]
+
+            # If the original parent had a name set, keep using it.  If the original
+            # parent didn't have a name but the child did, let the child's name
+            # live on.  If the name attribute seems unnecessary now, get rid of it.
+            if "name" in old_properties and old_properties["name"] not in (
+                None,
+                self.Name(),
+            ):
+                self._properties["name"] = old_properties["name"]
+            if (
+                "name" in self._properties
+                and "path" in self._properties
+                and self._properties["name"] == self._properties["path"]
+            ):
+                del self._properties["name"]
+
+            # Notify all children of their new parent.
+            for child in self._properties["children"]:
+                child.parent = self
+
+        # If asked to recurse, recurse.
+        if recurse:
+            for child in self._properties["children"]:
+                if child.__class__ == PBXGroup:
+                    child.TakeOverOnlyChild(recurse)
+
+    def SortGroup(self):
+        self._properties["children"] = sorted(
+            self._properties["children"], key=cmp_to_key(lambda x, y: x.Compare(y))
+        )
+
+        # Recurse.
+        for child in self._properties["children"]:
+            if isinstance(child, PBXGroup):
+                child.SortGroup()
+
+
+class XCFileLikeElement(XCHierarchicalElement):
+    # Abstract base for objects that can be used as the fileRef property of
+    # PBXBuildFile.
+
+    def PathHashables(self):
+        # A PBXBuildFile that refers to this object will call this method to
+        # obtain additional hashables specific to this XCFileLikeElement.  Don't
+        # just use this object's hashables, they're not specific and unique enough
+        # on their own (without access to the parent hashables.)  Instead, provide
+        # hashables that identify this object by path by getting its hashables as
+        # well as the hashables of ancestor XCHierarchicalElement objects.
+
+        hashables = []
+        xche = self
+        while isinstance(xche, XCHierarchicalElement):
+            xche_hashables = xche.Hashables()
+            for index, xche_hashable in enumerate(xche_hashables):
+                hashables.insert(index, xche_hashable)
+            xche = xche.parent
+        return hashables
+
+
+class XCContainerPortal(XCObject):
+    # Abstract base for objects that can be used as the containerPortal property
+    # of PBXContainerItemProxy.
+    pass
+
+
+class XCRemoteObject(XCObject):
+    # Abstract base for objects that can be used as the remoteGlobalIDString
+    # property of PBXContainerItemProxy.
+    pass
+
+
+class PBXFileReference(XCFileLikeElement, XCContainerPortal, XCRemoteObject):
+    _schema = XCFileLikeElement._schema.copy()
+    _schema.update(
+        {
+            "explicitFileType": [0, str, 0, 0],
+            "lastKnownFileType": [0, str, 0, 0],
+            "name": [0, str, 0, 0],
+            "path": [0, str, 0, 1],
+        }
+    )
+
+    # Weird output rules for PBXFileReference.
+    _should_print_single_line = True
+    # super
+    _encode_transforms = XCFileLikeElement._alternate_encode_transforms
+
+    def __init__(self, properties=None, id=None, parent=None):
+        # super
+        XCFileLikeElement.__init__(self, properties, id, parent)
+        if "path" in self._properties and self._properties["path"].endswith("/"):
+            self._properties["path"] = self._properties["path"][:-1]
+            is_dir = True
+        else:
+            is_dir = False
+
+        if (
+            "path" in self._properties
+            and "lastKnownFileType" not in self._properties
+            and "explicitFileType" not in self._properties
+        ):
+            # TODO(mark): This is the replacement for a replacement for a quick hack.
+            # It is no longer incredibly sucky, but this list needs to be extended.
+            extension_map = {
+                "a": "archive.ar",
+                "app": "wrapper.application",
+                "bdic": "file",
+                "bundle": "wrapper.cfbundle",
+                "c": "sourcecode.c.c",
+                "cc": "sourcecode.cpp.cpp",
+                "cpp": "sourcecode.cpp.cpp",
+                "css": "text.css",
+                "cxx": "sourcecode.cpp.cpp",
+                "dart": "sourcecode",
+                "dylib": "compiled.mach-o.dylib",
+                "framework": "wrapper.framework",
+                "gyp": "sourcecode",
+                "gypi": "sourcecode",
+                "h": "sourcecode.c.h",
+                "hxx": "sourcecode.cpp.h",
+                "icns": "image.icns",
+                "java": "sourcecode.java",
+                "js": "sourcecode.javascript",
+                "kext": "wrapper.kext",
+                "m": "sourcecode.c.objc",
+                "mm": "sourcecode.cpp.objcpp",
+                "nib": "wrapper.nib",
+                "o": "compiled.mach-o.objfile",
+                "pdf": "image.pdf",
+                "pl": "text.script.perl",
+                "plist": "text.plist.xml",
+                "pm": "text.script.perl",
+                "png": "image.png",
+                "py": "text.script.python",
+                "r": "sourcecode.rez",
+                "rez": "sourcecode.rez",
+                "s": "sourcecode.asm",
+                "storyboard": "file.storyboard",
+                "strings": "text.plist.strings",
+                "swift": "sourcecode.swift",
+                "ttf": "file",
+                "xcassets": "folder.assetcatalog",
+                "xcconfig": "text.xcconfig",
+                "xcdatamodel": "wrapper.xcdatamodel",
+                "xcdatamodeld": "wrapper.xcdatamodeld",
+                "xib": "file.xib",
+                "y": "sourcecode.yacc",
+            }
+
+            prop_map = {
+                "dart": "explicitFileType",
+                "gyp": "explicitFileType",
+                "gypi": "explicitFileType",
+            }
+
+            if is_dir:
+                file_type = "folder"
+                prop_name = "lastKnownFileType"
+            else:
+                basename = posixpath.basename(self._properties["path"])
+                (root, ext) = posixpath.splitext(basename)
+                # Check the map using a lowercase extension.
+                # TODO(mark): Maybe it should try with the original case first and fall
+                # back to lowercase, in case there are any instances where case
+                # matters.  There currently aren't.
+                if ext != "":
+                    ext = ext[1:].lower()
+
+                # TODO(mark): "text" is the default value, but "file" is appropriate
+                # for unrecognized files not containing text.  Xcode seems to choose
+                # based on content.
+                file_type = extension_map.get(ext, "text")
+                prop_name = prop_map.get(ext, "lastKnownFileType")
+
+            self._properties[prop_name] = file_type
+
+
+class PBXVariantGroup(PBXGroup, XCFileLikeElement):
+    """PBXVariantGroup is used by Xcode to represent localizations."""
+
+    # No additions to the schema relative to PBXGroup.
+    pass
+
+
+# PBXReferenceProxy is also an XCFileLikeElement subclass.  It is defined below
+# because it uses PBXContainerItemProxy, defined below.
+
+
+class XCBuildConfiguration(XCObject):
+    _schema = XCObject._schema.copy()
+    _schema.update(
+        {
+            "baseConfigurationReference": [0, PBXFileReference, 0, 0],
+            "buildSettings": [0, dict, 0, 1, {}],
+            "name": [0, str, 0, 1],
+        }
+    )
+
+    def HasBuildSetting(self, key):
+        return key in self._properties["buildSettings"]
+
+    def GetBuildSetting(self, key):
+        return self._properties["buildSettings"][key]
+
+    def SetBuildSetting(self, key, value):
+        # TODO(mark): If a list, copy?
+        self._properties["buildSettings"][key] = value
+
+    def AppendBuildSetting(self, key, value):
+        if key not in self._properties["buildSettings"]:
+            self._properties["buildSettings"][key] = []
+        self._properties["buildSettings"][key].append(value)
+
+    def DelBuildSetting(self, key):
+        if key in self._properties["buildSettings"]:
+            del self._properties["buildSettings"][key]
+
+    def SetBaseConfiguration(self, value):
+        self._properties["baseConfigurationReference"] = value
+
+
+class XCConfigurationList(XCObject):
+    # _configs is the default list of configurations.
+    _configs = [
+        XCBuildConfiguration({"name": "Debug"}),
+        XCBuildConfiguration({"name": "Release"}),
+    ]
+
+    _schema = XCObject._schema.copy()
+    _schema.update(
+        {
+            "buildConfigurations": [1, XCBuildConfiguration, 1, 1, _configs],
+            "defaultConfigurationIsVisible": [0, int, 0, 1, 1],
+            "defaultConfigurationName": [0, str, 0, 1, "Release"],
+        }
+    )
+
+    def Name(self):
+        return (
+            "Build configuration list for "
+            + self.parent.__class__.__name__
+            + ' "'
+            + self.parent.Name()
+            + '"'
+        )
+
+    def ConfigurationNamed(self, name):
+        """Convenience accessor to obtain an XCBuildConfiguration by name."""
+        for configuration in self._properties["buildConfigurations"]:
+            if configuration._properties["name"] == name:
+                return configuration
+
+        raise KeyError(name)
+
+    def DefaultConfiguration(self):
+        """Convenience accessor to obtain the default XCBuildConfiguration."""
+        return self.ConfigurationNamed(self._properties["defaultConfigurationName"])
+
+    def HasBuildSetting(self, key):
+        """Determines the state of a build setting in all XCBuildConfiguration
+    child objects.
+
+    If all child objects have key in their build settings, and the value is the
+    same in all child objects, returns 1.
+
+    If no child objects have the key in their build settings, returns 0.
+
+    If some, but not all, child objects have the key in their build settings,
+    or if any children have different values for the key, returns -1.
+    """
+
+        has = None
+        value = None
+        for configuration in self._properties["buildConfigurations"]:
+            configuration_has = configuration.HasBuildSetting(key)
+            if has is None:
+                has = configuration_has
+            elif has != configuration_has:
+                return -1
+
+            if configuration_has:
+                configuration_value = configuration.GetBuildSetting(key)
+                if value is None:
+                    value = configuration_value
+                elif value != configuration_value:
+                    return -1
+
+        if not has:
+            return 0
+
+        return 1
+
+    def GetBuildSetting(self, key):
+        """Gets the build setting for key.
+
+    All child XCConfiguration objects must have the same value set for the
+    setting, or a ValueError will be raised.
+    """
+
+        # TODO(mark): This is wrong for build settings that are lists.  The list
+        # contents should be compared (and a list copy returned?)
+
+        value = None
+        for configuration in self._properties["buildConfigurations"]:
+            configuration_value = configuration.GetBuildSetting(key)
+            if value is None:
+                value = configuration_value
+            else:
+                if value != configuration_value:
+                    raise ValueError("Variant values for " + key)
+
+        return value
+
+    def SetBuildSetting(self, key, value):
+        """Sets the build setting for key to value in all child
+    XCBuildConfiguration objects.
+    """
+
+        for configuration in self._properties["buildConfigurations"]:
+            configuration.SetBuildSetting(key, value)
+
+    def AppendBuildSetting(self, key, value):
+        """Appends value to the build setting for key, which is treated as a list,
+    in all child XCBuildConfiguration objects.
+    """
+
+        for configuration in self._properties["buildConfigurations"]:
+            configuration.AppendBuildSetting(key, value)
+
+    def DelBuildSetting(self, key):
+        """Deletes the build setting key from all child XCBuildConfiguration
+    objects.
+    """
+
+        for configuration in self._properties["buildConfigurations"]:
+            configuration.DelBuildSetting(key)
+
+    def SetBaseConfiguration(self, value):
+        """Sets the build configuration in all child XCBuildConfiguration objects.
+    """
+
+        for configuration in self._properties["buildConfigurations"]:
+            configuration.SetBaseConfiguration(value)
+
+
+class PBXBuildFile(XCObject):
+    _schema = XCObject._schema.copy()
+    _schema.update(
+        {
+            "fileRef": [0, XCFileLikeElement, 0, 1],
+            "settings": [0, str, 0, 0],  # hack, it's a dict
+        }
+    )
+
+    # Weird output rules for PBXBuildFile.
+    _should_print_single_line = True
+    _encode_transforms = XCObject._alternate_encode_transforms
+
+    def Name(self):
+        # Example: "main.cc in Sources"
+        return self._properties["fileRef"].Name() + " in " + self.parent.Name()
+
+    def Hashables(self):
+        # super
+        hashables = XCObject.Hashables(self)
+
+        # It is not sufficient to just rely on Name() to get the
+        # XCFileLikeElement's name, because that is not a complete pathname.
+        # PathHashables returns hashables unique enough that no two
+        # PBXBuildFiles should wind up with the same set of hashables, unless
+        # someone adds the same file multiple times to the same target.  That
+        # would be considered invalid anyway.
+        hashables.extend(self._properties["fileRef"].PathHashables())
+
+        return hashables
+
+
+class XCBuildPhase(XCObject):
+    """Abstract base for build phase classes.  Not represented in a project
+  file.
+
+  Attributes:
+    _files_by_path: A dict mapping each path of a child in the files list by
+      path (keys) to the corresponding PBXBuildFile children (values).
+    _files_by_xcfilelikeelement: A dict mapping each XCFileLikeElement (keys)
+      to the corresponding PBXBuildFile children (values).
+  """
+
+    # TODO(mark): Some build phase types, like PBXShellScriptBuildPhase, don't
+    # actually have a "files" list.  XCBuildPhase should not have "files" but
+    # another abstract subclass of it should provide this, and concrete build
+    # phase types that do have "files" lists should be derived from that new
+    # abstract subclass.  XCBuildPhase should only provide buildActionMask and
+    # runOnlyForDeploymentPostprocessing, and not files or the various
+    # file-related methods and attributes.
+
+    _schema = XCObject._schema.copy()
+    _schema.update(
+        {
+            "buildActionMask": [0, int, 0, 1, 0x7FFFFFFF],
+            "files": [1, PBXBuildFile, 1, 1, []],
+            "runOnlyForDeploymentPostprocessing": [0, int, 0, 1, 0],
+        }
+    )
+
+    def __init__(self, properties=None, id=None, parent=None):
+        # super
+        XCObject.__init__(self, properties, id, parent)
+
+        self._files_by_path = {}
+        self._files_by_xcfilelikeelement = {}
+        for pbxbuildfile in self._properties.get("files", []):
+            self._AddBuildFileToDicts(pbxbuildfile)
+
+    def FileGroup(self, path):
+        # Subclasses must override this by returning a two-element tuple.  The
+        # first item in the tuple should be the PBXGroup to which "path" should be
+        # added, either as a child or deeper descendant.  The second item should
+        # be a boolean indicating whether files should be added into hierarchical
+        # groups or one single flat group.
+        raise NotImplementedError(self.__class__.__name__ + " must implement FileGroup")
+
+    def _AddPathToDict(self, pbxbuildfile, path):
+        """Adds path to the dict tracking paths belonging to this build phase.
+
+    If the path is already a member of this build phase, raises an exception.
+    """
+
+        if path in self._files_by_path:
+            raise ValueError("Found multiple build files with path " + path)
+        self._files_by_path[path] = pbxbuildfile
+
+    def _AddBuildFileToDicts(self, pbxbuildfile, path=None):
+        """Maintains the _files_by_path and _files_by_xcfilelikeelement dicts.
+
+    If path is specified, then it is the path that is being added to the
+    phase, and pbxbuildfile must contain either a PBXFileReference directly
+    referencing that path, or it must contain a PBXVariantGroup that itself
+    contains a PBXFileReference referencing the path.
+
+    If path is not specified, either the PBXFileReference's path or the paths
+    of all children of the PBXVariantGroup are taken as being added to the
+    phase.
+
+    If the path is already present in the phase, raises an exception.
+
+    If the PBXFileReference or PBXVariantGroup referenced by pbxbuildfile
+    are already present in the phase, referenced by a different PBXBuildFile
+    object, raises an exception.  This does not raise an exception when
+    a PBXFileReference or PBXVariantGroup reappear and are referenced by the
+    same PBXBuildFile that has already introduced them, because in the case
+    of PBXVariantGroup objects, they may correspond to multiple paths that are
+    not all added simultaneously.  When this situation occurs, the path needs
+    to be added to _files_by_path, but nothing needs to change in
+    _files_by_xcfilelikeelement, and the caller should have avoided adding
+    the PBXBuildFile if it is already present in the list of children.
+    """
+
+        xcfilelikeelement = pbxbuildfile._properties["fileRef"]
+
+        paths = []
+        if path is not None:
+            # It's best when the caller provides the path.
+            if isinstance(xcfilelikeelement, PBXVariantGroup):
+                paths.append(path)
+        else:
+            # If the caller didn't provide a path, there can be either multiple
+            # paths (PBXVariantGroup) or one.
+            if isinstance(xcfilelikeelement, PBXVariantGroup):
+                for variant in xcfilelikeelement._properties["children"]:
+                    paths.append(variant.FullPath())
+            else:
+                paths.append(xcfilelikeelement.FullPath())
+
+        # Add the paths first, because if something's going to raise, the
+        # messages provided by _AddPathToDict are more useful owing to its
+        # having access to a real pathname and not just an object's Name().
+        for a_path in paths:
+            self._AddPathToDict(pbxbuildfile, a_path)
+
+        # If another PBXBuildFile references this XCFileLikeElement, there's a
+        # problem.
+        if (
+            xcfilelikeelement in self._files_by_xcfilelikeelement
+            and self._files_by_xcfilelikeelement[xcfilelikeelement] != pbxbuildfile
+        ):
+            raise ValueError(
+                "Found multiple build files for " + xcfilelikeelement.Name()
+            )
+        self._files_by_xcfilelikeelement[xcfilelikeelement] = pbxbuildfile
+
+    def AppendBuildFile(self, pbxbuildfile, path=None):
+        # Callers should use this instead of calling
+        # AppendProperty('files', pbxbuildfile) directly because this function
+        # maintains the object's dicts.  Better yet, callers can just call AddFile
+        # with a pathname and not worry about building their own PBXBuildFile
+        # objects.
+        self.AppendProperty("files", pbxbuildfile)
+        self._AddBuildFileToDicts(pbxbuildfile, path)
+
+    def AddFile(self, path, settings=None):
+        (file_group, hierarchical) = self.FileGroup(path)
+        file_ref = file_group.AddOrGetFileByPath(path, hierarchical)
+
+        if file_ref in self._files_by_xcfilelikeelement and isinstance(
+            file_ref, PBXVariantGroup
+        ):
+            # There's already a PBXBuildFile in this phase corresponding to the
+            # PBXVariantGroup.  path just provides a new variant that belongs to
+            # the group.  Add the path to the dict.
+            pbxbuildfile = self._files_by_xcfilelikeelement[file_ref]
+            self._AddBuildFileToDicts(pbxbuildfile, path)
+        else:
+            # Add a new PBXBuildFile to get file_ref into the phase.
+            if settings is None:
+                pbxbuildfile = PBXBuildFile({"fileRef": file_ref})
+            else:
+                pbxbuildfile = PBXBuildFile({"fileRef": file_ref, "settings": settings})
+            self.AppendBuildFile(pbxbuildfile, path)
+
+
+class PBXHeadersBuildPhase(XCBuildPhase):
+    # No additions to the schema relative to XCBuildPhase.
+
+    def Name(self):
+        return "Headers"
+
+    def FileGroup(self, path):
+        return self.PBXProjectAncestor().RootGroupForPath(path)
+
+
+class PBXResourcesBuildPhase(XCBuildPhase):
+    # No additions to the schema relative to XCBuildPhase.
+
+    def Name(self):
+        return "Resources"
+
+    def FileGroup(self, path):
+        return self.PBXProjectAncestor().RootGroupForPath(path)
+
+
+class PBXSourcesBuildPhase(XCBuildPhase):
+    # No additions to the schema relative to XCBuildPhase.
+
+    def Name(self):
+        return "Sources"
+
+    def FileGroup(self, path):
+        return self.PBXProjectAncestor().RootGroupForPath(path)
+
+
+class PBXFrameworksBuildPhase(XCBuildPhase):
+    # No additions to the schema relative to XCBuildPhase.
+
+    def Name(self):
+        return "Frameworks"
+
+    def FileGroup(self, path):
+        (root, ext) = posixpath.splitext(path)
+        if ext != "":
+            ext = ext[1:].lower()
+        if ext == "o":
+            # .o files are added to Xcode Frameworks phases, but conceptually aren't
+            # frameworks, they're more like sources or intermediates. Redirect them
+            # to show up in one of those other groups.
+            return self.PBXProjectAncestor().RootGroupForPath(path)
+        else:
+            return (self.PBXProjectAncestor().FrameworksGroup(), False)
+
+
+class PBXShellScriptBuildPhase(XCBuildPhase):
+    _schema = XCBuildPhase._schema.copy()
+    _schema.update(
+        {
+            "inputPaths": [1, str, 0, 1, []],
+            "name": [0, str, 0, 0],
+            "outputPaths": [1, str, 0, 1, []],
+            "shellPath": [0, str, 0, 1, "/bin/sh"],
+            "shellScript": [0, str, 0, 1],
+            "showEnvVarsInLog": [0, int, 0, 0],
+        }
+    )
+
+    def Name(self):
+        if "name" in self._properties:
+            return self._properties["name"]
+
+        return "ShellScript"
+
+
+class PBXCopyFilesBuildPhase(XCBuildPhase):
+    _schema = XCBuildPhase._schema.copy()
+    _schema.update(
+        {
+            "dstPath": [0, str, 0, 1],
+            "dstSubfolderSpec": [0, int, 0, 1],
+            "name": [0, str, 0, 0],
+        }
+    )
+
+    # path_tree_re matches "$(DIR)/path", "$(DIR)/$(DIR2)/path" or just "$(DIR)".
+    # Match group 1 is "DIR", group 3 is "path" or "$(DIR2") or "$(DIR2)/path"
+    # or None. If group 3 is "path", group 4 will be None otherwise group 4 is
+    # "DIR2" and group 6 is "path".
+    path_tree_re = re.compile(r"^\$$(.*?)$(/(\$$(.*?)$(/(.*)|)|(.*)|)|)$")
+
+    # path_tree_{first,second}_to_subfolder map names of Xcode variables to the
+    # associated dstSubfolderSpec property value used in a PBXCopyFilesBuildPhase
+    # object.
+    path_tree_first_to_subfolder = {
+        # Types that can be chosen via the Xcode UI.
+        "BUILT_PRODUCTS_DIR": 16,  # Products Directory
+        "BUILT_FRAMEWORKS_DIR": 10,  # Not an official Xcode macro.
+        # Existed before support for the
+        # names below was added. Maps to
+        # "Frameworks".
+    }
+
+    path_tree_second_to_subfolder = {
+        "WRAPPER_NAME": 1,  # Wrapper
+        # Although Xcode's friendly name is "Executables", the destination
+        # is demonstrably the value of the build setting
+        # EXECUTABLE_FOLDER_PATH not EXECUTABLES_FOLDER_PATH.
+        "EXECUTABLE_FOLDER_PATH": 6,  # Executables.
+        "UNLOCALIZED_RESOURCES_FOLDER_PATH": 7,  # Resources
+        "JAVA_FOLDER_PATH": 15,  # Java Resources
+        "FRAMEWORKS_FOLDER_PATH": 10,  # Frameworks
+        "SHARED_FRAMEWORKS_FOLDER_PATH": 11,  # Shared Frameworks
+        "SHARED_SUPPORT_FOLDER_PATH": 12,  # Shared Support
+        "PLUGINS_FOLDER_PATH": 13,  # PlugIns
+        # For XPC Services, Xcode sets both dstPath and dstSubfolderSpec.
+        # Note that it re-uses the BUILT_PRODUCTS_DIR value for
+        # dstSubfolderSpec. dstPath is set below.
+        "XPCSERVICES_FOLDER_PATH": 16,  # XPC Services.
+    }
+
+    def Name(self):
+        if "name" in self._properties:
+            return self._properties["name"]
+
+        return "CopyFiles"
+
+    def FileGroup(self, path):
+        return self.PBXProjectAncestor().RootGroupForPath(path)
+
+    def SetDestination(self, path):
+        """Set the dstSubfolderSpec and dstPath properties from path.
+
+    path may be specified in the same notation used for XCHierarchicalElements,
+    specifically, "$(DIR)/path".
+    """
+
+        path_tree_match = self.path_tree_re.search(path)
+        if path_tree_match:
+            path_tree = path_tree_match.group(1)
+            if path_tree in self.path_tree_first_to_subfolder:
+                subfolder = self.path_tree_first_to_subfolder[path_tree]
+                relative_path = path_tree_match.group(3)
+                if relative_path is None:
+                    relative_path = ""
+
+                if subfolder == 16 and path_tree_match.group(4) is not None:
+                    # BUILT_PRODUCTS_DIR (16) is the first element in a path whose
+                    # second element is possibly one of the variable names in
+                    # path_tree_second_to_subfolder. Xcode sets the values of all these
+                    # variables to relative paths so .gyp files must prefix them with
+                    # BUILT_PRODUCTS_DIR, e.g.
+                    # $(BUILT_PRODUCTS_DIR)/$(PLUGINS_FOLDER_PATH). Then
+                    # xcode_emulation.py can export these variables with the same values
+                    # as Xcode yet make & ninja files can determine the absolute path
+                    # to the target. Xcode uses the dstSubfolderSpec value set here
+                    # to determine the full path.
+                    #
+                    # An alternative of xcode_emulation.py setting the values to
+                    # absolute paths when exporting these variables has been
+                    # ruled out because then the values would be different
+                    # depending on the build tool.
+                    #
+                    # Another alternative is to invent new names for the variables used
+                    # to match to the subfolder indices in the second table. .gyp files
+                    # then will not need to prepend $(BUILT_PRODUCTS_DIR) because
+                    # xcode_emulation.py can set the values of those variables to
+                    # the absolute paths when exporting. This is possibly the thinking
+                    # behind BUILT_FRAMEWORKS_DIR which is used in exactly this manner.
+                    #
+                    # Requiring prepending BUILT_PRODUCTS_DIR has been chosen because
+                    # this same way could be used to specify destinations in .gyp files
+                    # that pre-date this addition to GYP. However they would only work
+                    # with the Xcode generator.
+                    # The previous version of xcode_emulation.py
+                    # does not export these variables. Such files will get the benefit
+                    # of the Xcode UI showing the proper destination name simply by
+                    # regenerating the projects with this version of GYP.
+                    path_tree = path_tree_match.group(4)
+                    relative_path = path_tree_match.group(6)
+                    separator = "/"
+
+                    if path_tree in self.path_tree_second_to_subfolder:
+                        subfolder = self.path_tree_second_to_subfolder[path_tree]
+                        if relative_path is None:
+                            relative_path = ""
+                            separator = ""
+                        if path_tree == "XPCSERVICES_FOLDER_PATH":
+                            relative_path = (
+                                "$(CONTENTS_FOLDER_PATH)/XPCServices"
+                                + separator
+                                + relative_path
+                            )
+                    else:
+                        # subfolder = 16 from above
+                        # The second element of the path is an unrecognized variable.
+                        # Include it and any remaining elements in relative_path.
+                        relative_path = path_tree_match.group(3)
+
+            else:
+                # The path starts with an unrecognized Xcode variable
+                # name like $(SRCROOT).  Xcode will still handle this
+                # as an "absolute path" that starts with the variable.
+                subfolder = 0
+                relative_path = path
+        elif path.startswith("/"):
+            # Special case.  Absolute paths are in dstSubfolderSpec 0.
+            subfolder = 0
+            relative_path = path[1:]
+        else:
+            raise ValueError(
+                f"Can't use path {path} in a {self.__class__.__name__}"
+            )
+
+        self._properties["dstPath"] = relative_path
+        self._properties["dstSubfolderSpec"] = subfolder
+
+
+class PBXBuildRule(XCObject):
+    _schema = XCObject._schema.copy()
+    _schema.update(
+        {
+            "compilerSpec": [0, str, 0, 1],
+            "filePatterns": [0, str, 0, 0],
+            "fileType": [0, str, 0, 1],
+            "isEditable": [0, int, 0, 1, 1],
+            "outputFiles": [1, str, 0, 1, []],
+            "script": [0, str, 0, 0],
+        }
+    )
+
+    def Name(self):
+        # Not very inspired, but it's what Xcode uses.
+        return self.__class__.__name__
+
+    def Hashables(self):
+        # super
+        hashables = XCObject.Hashables(self)
+
+        # Use the hashables of the weak objects that this object refers to.
+        hashables.append(self._properties["fileType"])
+        if "filePatterns" in self._properties:
+            hashables.append(self._properties["filePatterns"])
+        return hashables
+
+
+class PBXContainerItemProxy(XCObject):
+    # When referencing an item in this project file, containerPortal is the
+    # PBXProject root object of this project file.  When referencing an item in
+    # another project file, containerPortal is a PBXFileReference identifying
+    # the other project file.
+    #
+    # When serving as a proxy to an XCTarget (in this project file or another),
+    # proxyType is 1.  When serving as a proxy to a PBXFileReference (in another
+    # project file), proxyType is 2.  Type 2 is used for references to the
+    # producs of the other project file's targets.
+    #
+    # Xcode is weird about remoteGlobalIDString.  Usually, it's printed without
+    # a comment, indicating that it's tracked internally simply as a string, but
+    # sometimes it's printed with a comment (usually when the object is initially
+    # created), indicating that it's tracked as a project file object at least
+    # sometimes.  This module always tracks it as an object, but contains a hack
+    # to prevent it from printing the comment in the project file output.  See
+    # _XCKVPrint.
+    _schema = XCObject._schema.copy()
+    _schema.update(
+        {
+            "containerPortal": [0, XCContainerPortal, 0, 1],
+            "proxyType": [0, int, 0, 1],
+            "remoteGlobalIDString": [0, XCRemoteObject, 0, 1],
+            "remoteInfo": [0, str, 0, 1],
+        }
+    )
+
+    def __repr__(self):
+        props = self._properties
+        name = "{}.gyp:{}".format(props["containerPortal"].Name(), props["remoteInfo"])
+        return f"<{self.__class__.__name__} {name!r} at 0x{id(self):x}>"
+
+    def Name(self):
+        # Admittedly not the best name, but it's what Xcode uses.
+        return self.__class__.__name__
+
+    def Hashables(self):
+        # super
+        hashables = XCObject.Hashables(self)
+
+        # Use the hashables of the weak objects that this object refers to.
+        hashables.extend(self._properties["containerPortal"].Hashables())
+        hashables.extend(self._properties["remoteGlobalIDString"].Hashables())
+        return hashables
+
+
+class PBXTargetDependency(XCObject):
+    # The "target" property accepts an XCTarget object, and obviously not
+    # NoneType.  But XCTarget is defined below, so it can't be put into the
+    # schema yet.  The definition of PBXTargetDependency can't be moved below
+    # XCTarget because XCTarget's own schema references PBXTargetDependency.
+    # Python doesn't deal well with this circular relationship, and doesn't have
+    # a real way to do forward declarations.  To work around, the type of
+    # the "target" property is reset below, after XCTarget is defined.
+    #
+    # At least one of "name" and "target" is required.
+    _schema = XCObject._schema.copy()
+    _schema.update(
+        {
+            "name": [0, str, 0, 0],
+            "target": [0, None.__class__, 0, 0],
+            "targetProxy": [0, PBXContainerItemProxy, 1, 1],
+        }
+    )
+
+    def __repr__(self):
+        name = self._properties.get("name") or self._properties["target"].Name()
+        return f"<{self.__class__.__name__} {name!r} at 0x{id(self):x}>"
+
+    def Name(self):
+        # Admittedly not the best name, but it's what Xcode uses.
+        return self.__class__.__name__
+
+    def Hashables(self):
+        # super
+        hashables = XCObject.Hashables(self)
+
+        # Use the hashables of the weak objects that this object refers to.
+        hashables.extend(self._properties["targetProxy"].Hashables())
+        return hashables
+
+
+class PBXReferenceProxy(XCFileLikeElement):
+    _schema = XCFileLikeElement._schema.copy()
+    _schema.update(
+        {
+            "fileType": [0, str, 0, 1],
+            "path": [0, str, 0, 1],
+            "remoteRef": [0, PBXContainerItemProxy, 1, 1],
+        }
+    )
+
+
+class XCTarget(XCRemoteObject):
+    # An XCTarget is really just an XCObject, the XCRemoteObject thing is just
+    # to allow PBXProject to be used in the remoteGlobalIDString property of
+    # PBXContainerItemProxy.
+    #
+    # Setting a "name" property at instantiation may also affect "productName",
+    # which may in turn affect the "PRODUCT_NAME" build setting in children of
+    # "buildConfigurationList".  See __init__ below.
+    _schema = XCRemoteObject._schema.copy()
+    _schema.update(
+        {
+            "buildConfigurationList": [
+                0,
+                XCConfigurationList,
+                1,
+                1,
+                XCConfigurationList(),
+            ],
+            "buildPhases": [1, XCBuildPhase, 1, 1, []],
+            "dependencies": [1, PBXTargetDependency, 1, 1, []],
+            "name": [0, str, 0, 1],
+            "productName": [0, str, 0, 1],
+        }
+    )
+
+    def __init__(
+        self,
+        properties=None,
+        id=None,
+        parent=None,
+        force_outdir=None,
+        force_prefix=None,
+        force_extension=None,
+    ):
+        # super
+        XCRemoteObject.__init__(self, properties, id, parent)
+
+        # Set up additional defaults not expressed in the schema.  If a "name"
+        # property was supplied, set "productName" if it is not present.  Also set
+        # the "PRODUCT_NAME" build setting in each configuration, but only if
+        # the setting is not present in any build configuration.
+        if "name" in self._properties:
+            if "productName" not in self._properties:
+                self.SetProperty("productName", self._properties["name"])
+
+        if "productName" in self._properties:
+            if "buildConfigurationList" in self._properties:
+                configs = self._properties["buildConfigurationList"]
+                if configs.HasBuildSetting("PRODUCT_NAME") == 0:
+                    configs.SetBuildSetting(
+                        "PRODUCT_NAME", self._properties["productName"]
+                    )
+
+    def AddDependency(self, other):
+        pbxproject = self.PBXProjectAncestor()
+        other_pbxproject = other.PBXProjectAncestor()
+        if pbxproject == other_pbxproject:
+            # Add a dependency to another target in the same project file.
+            container = PBXContainerItemProxy(
+                {
+                    "containerPortal": pbxproject,
+                    "proxyType": 1,
+                    "remoteGlobalIDString": other,
+                    "remoteInfo": other.Name(),
+                }
+            )
+            dependency = PBXTargetDependency(
+                {"target": other, "targetProxy": container}
+            )
+            self.AppendProperty("dependencies", dependency)
+        else:
+            # Add a dependency to a target in a different project file.
+            other_project_ref = pbxproject.AddOrGetProjectReference(other_pbxproject)[1]
+            container = PBXContainerItemProxy(
+                {
+                    "containerPortal": other_project_ref,
+                    "proxyType": 1,
+                    "remoteGlobalIDString": other,
+                    "remoteInfo": other.Name(),
+                }
+            )
+            dependency = PBXTargetDependency(
+                {"name": other.Name(), "targetProxy": container}
+            )
+            self.AppendProperty("dependencies", dependency)
+
+    # Proxy all of these through to the build configuration list.
+
+    def ConfigurationNamed(self, name):
+        return self._properties["buildConfigurationList"].ConfigurationNamed(name)
+
+    def DefaultConfiguration(self):
+        return self._properties["buildConfigurationList"].DefaultConfiguration()
+
+    def HasBuildSetting(self, key):
+        return self._properties["buildConfigurationList"].HasBuildSetting(key)
+
+    def GetBuildSetting(self, key):
+        return self._properties["buildConfigurationList"].GetBuildSetting(key)
+
+    def SetBuildSetting(self, key, value):
+        return self._properties["buildConfigurationList"].SetBuildSetting(key, value)
+
+    def AppendBuildSetting(self, key, value):
+        return self._properties["buildConfigurationList"].AppendBuildSetting(key, value)
+
+    def DelBuildSetting(self, key):
+        return self._properties["buildConfigurationList"].DelBuildSetting(key)
+
+
+# Redefine the type of the "target" property.  See PBXTargetDependency._schema
+# above.
+PBXTargetDependency._schema["target"][1] = XCTarget
+
+
+class PBXNativeTarget(XCTarget):
+    # buildPhases is overridden in the schema to be able to set defaults.
+    #
+    # NOTE: Contrary to most objects, it is advisable to set parent when
+    # constructing PBXNativeTarget.  A parent of an XCTarget must be a PBXProject
+    # object.  A parent reference is required for a PBXNativeTarget during
+    # construction to be able to set up the target defaults for productReference,
+    # because a PBXBuildFile object must be created for the target and it must
+    # be added to the PBXProject's mainGroup hierarchy.
+    _schema = XCTarget._schema.copy()
+    _schema.update(
+        {
+            "buildPhases": [
+                1,
+                XCBuildPhase,
+                1,
+                1,
+                [PBXSourcesBuildPhase(), PBXFrameworksBuildPhase()],
+            ],
+            "buildRules": [1, PBXBuildRule, 1, 1, []],
+            "productReference": [0, PBXFileReference, 0, 1],
+            "productType": [0, str, 0, 1],
+        }
+    )
+
+    # Mapping from Xcode product-types to settings.  The settings are:
+    #  filetype : used for explicitFileType in the project file
+    #  prefix : the prefix for the file name
+    #  suffix : the suffix for the file name
+    _product_filetypes = {
+        "com.apple.product-type.application": ["wrapper.application", "", ".app"],
+        "com.apple.product-type.application.watchapp": [
+            "wrapper.application",
+            "",
+            ".app",
+        ],
+        "com.apple.product-type.watchkit-extension": [
+            "wrapper.app-extension",
+            "",
+            ".appex",
+        ],
+        "com.apple.product-type.app-extension": ["wrapper.app-extension", "", ".appex"],
+        "com.apple.product-type.bundle": ["wrapper.cfbundle", "", ".bundle"],
+        "com.apple.product-type.framework": ["wrapper.framework", "", ".framework"],
+        "com.apple.product-type.library.dynamic": [
+            "compiled.mach-o.dylib",
+            "lib",
+            ".dylib",
+        ],
+        "com.apple.product-type.library.static": ["archive.ar", "lib", ".a"],
+        "com.apple.product-type.tool": ["compiled.mach-o.executable", "", ""],
+        "com.apple.product-type.bundle.unit-test": ["wrapper.cfbundle", "", ".xctest"],
+        "com.apple.product-type.bundle.ui-testing": ["wrapper.cfbundle", "", ".xctest"],
+        "com.googlecode.gyp.xcode.bundle": ["compiled.mach-o.dylib", "", ".so"],
+        "com.apple.product-type.kernel-extension": ["wrapper.kext", "", ".kext"],
+    }
+
+    def __init__(
+        self,
+        properties=None,
+        id=None,
+        parent=None,
+        force_outdir=None,
+        force_prefix=None,
+        force_extension=None,
+    ):
+        # super
+        XCTarget.__init__(self, properties, id, parent)
+
+        if (
+            "productName" in self._properties
+            and "productType" in self._properties
+            and "productReference" not in self._properties
+            and self._properties["productType"] in self._product_filetypes
+        ):
+            products_group = None
+            pbxproject = self.PBXProjectAncestor()
+            if pbxproject is not None:
+                products_group = pbxproject.ProductsGroup()
+
+            if products_group is not None:
+                (filetype, prefix, suffix) = self._product_filetypes[
+                    self._properties["productType"]
+                ]
+                # Xcode does not have a distinct type for loadable modules that are
+                # pure BSD targets (not in a bundle wrapper). GYP allows such modules
+                # to be specified by setting a target type to loadable_module without
+                # having mac_bundle set. These are mapped to the pseudo-product type
+                # com.googlecode.gyp.xcode.bundle.
+                #
+                # By picking up this special type and converting it to a dynamic
+                # library (com.apple.product-type.library.dynamic) with fix-ups,
+                # single-file loadable modules can be produced.
+                #
+                # MACH_O_TYPE is changed to mh_bundle to produce the proper file type
+                # (as opposed to mh_dylib). In order for linking to succeed,
+                # DYLIB_CURRENT_VERSION and DYLIB_COMPATIBILITY_VERSION must be
+                # cleared. They are meaningless for type mh_bundle.
+                #
+                # Finally, the .so extension is forcibly applied over the default
+                # (.dylib), unless another forced extension is already selected.
+                # .dylib is plainly wrong, and .bundle is used by loadable_modules in
+                # bundle wrappers (com.apple.product-type.bundle). .so seems an odd
+                # choice because it's used as the extension on many other systems that
+                # don't distinguish between linkable shared libraries and non-linkable
+                # loadable modules, but there's precedent: Python loadable modules on
+                # Mac OS X use an .so extension.
+                if self._properties["productType"] == "com.googlecode.gyp.xcode.bundle":
+                    self._properties[
+                        "productType"
+                    ] = "com.apple.product-type.library.dynamic"
+                    self.SetBuildSetting("MACH_O_TYPE", "mh_bundle")
+                    self.SetBuildSetting("DYLIB_CURRENT_VERSION", "")
+                    self.SetBuildSetting("DYLIB_COMPATIBILITY_VERSION", "")
+                    if force_extension is None:
+                        force_extension = suffix[1:]
+
+                if (
+                    self._properties["productType"]
+                    == "com.apple.product-type-bundle.unit.test"
+                    or self._properties["productType"]
+                    == "com.apple.product-type-bundle.ui-testing"
+                ):
+                    if force_extension is None:
+                        force_extension = suffix[1:]
+
+                if force_extension is not None:
+                    # If it's a wrapper (bundle), set WRAPPER_EXTENSION.
+                    # Extension override.
+                    suffix = "." + force_extension
+                    if filetype.startswith("wrapper."):
+                        self.SetBuildSetting("WRAPPER_EXTENSION", force_extension)
+                    else:
+                        self.SetBuildSetting("EXECUTABLE_EXTENSION", force_extension)
+
+                    if filetype.startswith("compiled.mach-o.executable"):
+                        product_name = self._properties["productName"]
+                        product_name += suffix
+                        suffix = ""
+                        self.SetProperty("productName", product_name)
+                        self.SetBuildSetting("PRODUCT_NAME", product_name)
+
+                # Xcode handles most prefixes based on the target type, however there
+                # are exceptions.  If a "BSD Dynamic Library" target is added in the
+                # Xcode UI, Xcode sets EXECUTABLE_PREFIX.  This check duplicates that
+                # behavior.
+                if force_prefix is not None:
+                    prefix = force_prefix
+                if filetype.startswith("wrapper."):
+                    self.SetBuildSetting("WRAPPER_PREFIX", prefix)
+                else:
+                    self.SetBuildSetting("EXECUTABLE_PREFIX", prefix)
+
+                if force_outdir is not None:
+                    self.SetBuildSetting("TARGET_BUILD_DIR", force_outdir)
+
+                # TODO(tvl): Remove the below hack.
+                #    http://code.google.com/p/gyp/issues/detail?id=122
+
+                # Some targets include the prefix in the target_name.  These targets
+                # really should just add a product_name setting that doesn't include
+                # the prefix.  For example:
+                #  target_name = 'libevent', product_name = 'event'
+                # This check cleans up for them.
+                product_name = self._properties["productName"]
+                prefix_len = len(prefix)
+                if prefix_len and (product_name[:prefix_len] == prefix):
+                    product_name = product_name[prefix_len:]
+                    self.SetProperty("productName", product_name)
+                    self.SetBuildSetting("PRODUCT_NAME", product_name)
+
+                ref_props = {
+                    "explicitFileType": filetype,
+                    "includeInIndex": 0,
+                    "path": prefix + product_name + suffix,
+                    "sourceTree": "BUILT_PRODUCTS_DIR",
+                }
+                file_ref = PBXFileReference(ref_props)
+                products_group.AppendChild(file_ref)
+                self.SetProperty("productReference", file_ref)
+
+    def GetBuildPhaseByType(self, type):
+        if "buildPhases" not in self._properties:
+            return None
+
+        the_phase = None
+        for phase in self._properties["buildPhases"]:
+            if isinstance(phase, type):
+                # Some phases may be present in multiples in a well-formed project file,
+                # but phases like PBXSourcesBuildPhase may only be present singly, and
+                # this function is intended as an aid to GetBuildPhaseByType.  Loop
+                # over the entire list of phases and assert if more than one of the
+                # desired type is found.
+                assert the_phase is None
+                the_phase = phase
+
+        return the_phase
+
+    def HeadersPhase(self):
+        headers_phase = self.GetBuildPhaseByType(PBXHeadersBuildPhase)
+        if headers_phase is None:
+            headers_phase = PBXHeadersBuildPhase()
+
+            # The headers phase should come before the resources, sources, and
+            # frameworks phases, if any.
+            insert_at = len(self._properties["buildPhases"])
+            for index, phase in enumerate(self._properties["buildPhases"]):
+                if (
+                    isinstance(phase, PBXResourcesBuildPhase)
+                    or isinstance(phase, PBXSourcesBuildPhase)
+                    or isinstance(phase, PBXFrameworksBuildPhase)
+                ):
+                    insert_at = index
+                    break
+
+            self._properties["buildPhases"].insert(insert_at, headers_phase)
+            headers_phase.parent = self
+
+        return headers_phase
+
+    def ResourcesPhase(self):
+        resources_phase = self.GetBuildPhaseByType(PBXResourcesBuildPhase)
+        if resources_phase is None:
+            resources_phase = PBXResourcesBuildPhase()
+
+            # The resources phase should come before the sources and frameworks
+            # phases, if any.
+            insert_at = len(self._properties["buildPhases"])
+            for index, phase in enumerate(self._properties["buildPhases"]):
+                if isinstance(phase, PBXSourcesBuildPhase) or isinstance(
+                    phase, PBXFrameworksBuildPhase
+                ):
+                    insert_at = index
+                    break
+
+            self._properties["buildPhases"].insert(insert_at, resources_phase)
+            resources_phase.parent = self
+
+        return resources_phase
+
+    def SourcesPhase(self):
+        sources_phase = self.GetBuildPhaseByType(PBXSourcesBuildPhase)
+        if sources_phase is None:
+            sources_phase = PBXSourcesBuildPhase()
+            self.AppendProperty("buildPhases", sources_phase)
+
+        return sources_phase
+
+    def FrameworksPhase(self):
+        frameworks_phase = self.GetBuildPhaseByType(PBXFrameworksBuildPhase)
+        if frameworks_phase is None:
+            frameworks_phase = PBXFrameworksBuildPhase()
+            self.AppendProperty("buildPhases", frameworks_phase)
+
+        return frameworks_phase
+
+    def AddDependency(self, other):
+        # super
+        XCTarget.AddDependency(self, other)
+
+        static_library_type = "com.apple.product-type.library.static"
+        shared_library_type = "com.apple.product-type.library.dynamic"
+        framework_type = "com.apple.product-type.framework"
+        if (
+            isinstance(other, PBXNativeTarget)
+            and "productType" in self._properties
+            and self._properties["productType"] != static_library_type
+            and "productType" in other._properties
+            and (
+                other._properties["productType"] == static_library_type
+                or (
+                    (
+                        other._properties["productType"] == shared_library_type
+                        or other._properties["productType"] == framework_type
+                    )
+                    and (
+                        (not other.HasBuildSetting("MACH_O_TYPE"))
+                        or other.GetBuildSetting("MACH_O_TYPE") != "mh_bundle"
+                    )
+                )
+            )
+        ):
+
+            file_ref = other.GetProperty("productReference")
+
+            pbxproject = self.PBXProjectAncestor()
+            other_pbxproject = other.PBXProjectAncestor()
+            if pbxproject != other_pbxproject:
+                other_project_product_group = pbxproject.AddOrGetProjectReference(
+                    other_pbxproject
+                )[0]
+                file_ref = other_project_product_group.GetChildByRemoteObject(file_ref)
+
+            self.FrameworksPhase().AppendProperty(
+                "files", PBXBuildFile({"fileRef": file_ref})
+            )
+
+
+class PBXAggregateTarget(XCTarget):
+    pass
+
+
+class PBXProject(XCContainerPortal):
+    # A PBXProject is really just an XCObject, the XCContainerPortal thing is
+    # just to allow PBXProject to be used in the containerPortal property of
+    # PBXContainerItemProxy.
+    """
+
+  Attributes:
+    path: "sample.xcodeproj".  TODO(mark) Document me!
+    _other_pbxprojects: A dictionary, keyed by other PBXProject objects.  Each
+                        value is a reference to the dict in the
+                        projectReferences list associated with the keyed
+                        PBXProject.
+  """
+
+    _schema = XCContainerPortal._schema.copy()
+    _schema.update(
+        {
+            "attributes": [0, dict, 0, 0],
+            "buildConfigurationList": [
+                0,
+                XCConfigurationList,
+                1,
+                1,
+                XCConfigurationList(),
+            ],
+            "compatibilityVersion": [0, str, 0, 1, "Xcode 3.2"],
+            "hasScannedForEncodings": [0, int, 0, 1, 1],
+            "mainGroup": [0, PBXGroup, 1, 1, PBXGroup()],
+            "projectDirPath": [0, str, 0, 1, ""],
+            "projectReferences": [1, dict, 0, 0],
+            "projectRoot": [0, str, 0, 1, ""],
+            "targets": [1, XCTarget, 1, 1, []],
+        }
+    )
+
+    def __init__(self, properties=None, id=None, parent=None, path=None):
+        self.path = path
+        self._other_pbxprojects = {}
+        # super
+        return XCContainerPortal.__init__(self, properties, id, parent)
+
+    def Name(self):
+        name = self.path
+        if name[-10:] == ".xcodeproj":
+            name = name[:-10]
+        return posixpath.basename(name)
+
+    def Path(self):
+        return self.path
+
+    def Comment(self):
+        return "Project object"
+
+    def Children(self):
+        # super
+        children = XCContainerPortal.Children(self)
+
+        # Add children that the schema doesn't know about.  Maybe there's a more
+        # elegant way around this, but this is the only case where we need to own
+        # objects in a dictionary (that is itself in a list), and three lines for
+        # a one-off isn't that big a deal.
+        if "projectReferences" in self._properties:
+            for reference in self._properties["projectReferences"]:
+                children.append(reference["ProductGroup"])
+
+        return children
+
+    def PBXProjectAncestor(self):
+        return self
+
+    def _GroupByName(self, name):
+        if "mainGroup" not in self._properties:
+            self.SetProperty("mainGroup", PBXGroup())
+
+        main_group = self._properties["mainGroup"]
+        group = main_group.GetChildByName(name)
+        if group is None:
+            group = PBXGroup({"name": name})
+            main_group.AppendChild(group)
+
+        return group
+
+    # SourceGroup and ProductsGroup are created by default in Xcode's own
+    # templates.
+    def SourceGroup(self):
+        return self._GroupByName("Source")
+
+    def ProductsGroup(self):
+        return self._GroupByName("Products")
+
+    # IntermediatesGroup is used to collect source-like files that are generated
+    # by rules or script phases and are placed in intermediate directories such
+    # as DerivedSources.
+    def IntermediatesGroup(self):
+        return self._GroupByName("Intermediates")
+
+    # FrameworksGroup and ProjectsGroup are top-level groups used to collect
+    # frameworks and projects.
+    def FrameworksGroup(self):
+        return self._GroupByName("Frameworks")
+
+    def ProjectsGroup(self):
+        return self._GroupByName("Projects")
+
+    def RootGroupForPath(self, path):
+        """Returns a PBXGroup child of this object to which path should be added.
+
+    This method is intended to choose between SourceGroup and
+    IntermediatesGroup on the basis of whether path is present in a source
+    directory or an intermediates directory.  For the purposes of this
+    determination, any path located within a derived file directory such as
+    PROJECT_DERIVED_FILE_DIR is treated as being in an intermediates
+    directory.
+
+    The returned value is a two-element tuple.  The first element is the
+    PBXGroup, and the second element specifies whether that group should be
+    organized hierarchically (True) or as a single flat list (False).
+    """
+
+        # TODO(mark): make this a class variable and bind to self on call?
+        # Also, this list is nowhere near exhaustive.
+        # INTERMEDIATE_DIR and SHARED_INTERMEDIATE_DIR are used by
+        # gyp.generator.xcode.  There should probably be some way for that module
+        # to push the names in, rather than having to hard-code them here.
+        source_tree_groups = {
+            "DERIVED_FILE_DIR": (self.IntermediatesGroup, True),
+            "INTERMEDIATE_DIR": (self.IntermediatesGroup, True),
+            "PROJECT_DERIVED_FILE_DIR": (self.IntermediatesGroup, True),
+            "SHARED_INTERMEDIATE_DIR": (self.IntermediatesGroup, True),
+        }
+
+        (source_tree, path) = SourceTreeAndPathFromPath(path)
+        if source_tree is not None and source_tree in source_tree_groups:
+            (group_func, hierarchical) = source_tree_groups[source_tree]
+            group = group_func()
+            return (group, hierarchical)
+
+        # TODO(mark): make additional choices based on file extension.
+
+        return (self.SourceGroup(), True)
+
+    def AddOrGetFileInRootGroup(self, path):
+        """Returns a PBXFileReference corresponding to path in the correct group
+    according to RootGroupForPath's heuristics.
+
+    If an existing PBXFileReference for path exists, it will be returned.
+    Otherwise, one will be created and returned.
+    """
+
+        (group, hierarchical) = self.RootGroupForPath(path)
+        return group.AddOrGetFileByPath(path, hierarchical)
+
+    def RootGroupsTakeOverOnlyChildren(self, recurse=False):
+        """Calls TakeOverOnlyChild for all groups in the main group."""
+
+        for group in self._properties["mainGroup"]._properties["children"]:
+            if isinstance(group, PBXGroup):
+                group.TakeOverOnlyChild(recurse)
+
+    def SortGroups(self):
+        # Sort the children of the mainGroup (like "Source" and "Products")
+        # according to their defined order.
+        self._properties["mainGroup"]._properties["children"] = sorted(
+            self._properties["mainGroup"]._properties["children"],
+            key=cmp_to_key(lambda x, y: x.CompareRootGroup(y)),
+        )
+
+        # Sort everything else by putting group before files, and going
+        # alphabetically by name within sections of groups and files.  SortGroup
+        # is recursive.
+        for group in self._properties["mainGroup"]._properties["children"]:
+            if not isinstance(group, PBXGroup):
+                continue
+
+            if group.Name() == "Products":
+                # The Products group is a special case.  Instead of sorting
+                # alphabetically, sort things in the order of the targets that
+                # produce the products.  To do this, just build up a new list of
+                # products based on the targets.
+                products = []
+                for target in self._properties["targets"]:
+                    if not isinstance(target, PBXNativeTarget):
+                        continue
+                    product = target._properties["productReference"]
+                    # Make sure that the product is already in the products group.
+                    assert product in group._properties["children"]
+                    products.append(product)
+
+                # Make sure that this process doesn't miss anything that was already
+                # in the products group.
+                assert len(products) == len(group._properties["children"])
+                group._properties["children"] = products
+            else:
+                group.SortGroup()
+
+    def AddOrGetProjectReference(self, other_pbxproject):
+        """Add a reference to another project file (via PBXProject object) to this
+    one.
+
+    Returns [ProductGroup, ProjectRef].  ProductGroup is a PBXGroup object in
+    this project file that contains a PBXReferenceProxy object for each
+    product of each PBXNativeTarget in the other project file.  ProjectRef is
+    a PBXFileReference to the other project file.
+
+    If this project file already references the other project file, the
+    existing ProductGroup and ProjectRef are returned.  The ProductGroup will
+    still be updated if necessary.
+    """
+
+        if "projectReferences" not in self._properties:
+            self._properties["projectReferences"] = []
+
+        product_group = None
+        project_ref = None
+
+        if other_pbxproject not in self._other_pbxprojects:
+            # This project file isn't yet linked to the other one.  Establish the
+            # link.
+            product_group = PBXGroup({"name": "Products"})
+
+            # ProductGroup is strong.
+            product_group.parent = self
+
+            # There's nothing unique about this PBXGroup, and if left alone, it will
+            # wind up with the same set of hashables as all other PBXGroup objects
+            # owned by the projectReferences list.  Add the hashables of the
+            # remote PBXProject that it's related to.
+            product_group._hashables.extend(other_pbxproject.Hashables())
+
+            # The other project reports its path as relative to the same directory
+            # that this project's path is relative to.  The other project's path
+            # is not necessarily already relative to this project.  Figure out the
+            # pathname that this project needs to use to refer to the other one.
+            this_path = posixpath.dirname(self.Path())
+            projectDirPath = self.GetProperty("projectDirPath")
+            if projectDirPath:
+                if posixpath.isabs(projectDirPath[0]):
+                    this_path = projectDirPath
+                else:
+                    this_path = posixpath.join(this_path, projectDirPath)
+            other_path = gyp.common.RelativePath(other_pbxproject.Path(), this_path)
+
+            # ProjectRef is weak (it's owned by the mainGroup hierarchy).
+            project_ref = PBXFileReference(
+                {
+                    "lastKnownFileType": "wrapper.pb-project",
+                    "path": other_path,
+                    "sourceTree": "SOURCE_ROOT",
+                }
+            )
+            self.ProjectsGroup().AppendChild(project_ref)
+
+            ref_dict = {"ProductGroup": product_group, "ProjectRef": project_ref}
+            self._other_pbxprojects[other_pbxproject] = ref_dict
+            self.AppendProperty("projectReferences", ref_dict)
+
+            # Xcode seems to sort this list case-insensitively
+            self._properties["projectReferences"] = sorted(
+                self._properties["projectReferences"],
+                key=lambda x: x["ProjectRef"].Name().lower
+            )
+        else:
+            # The link already exists.  Pull out the relevnt data.
+            project_ref_dict = self._other_pbxprojects[other_pbxproject]
+            product_group = project_ref_dict["ProductGroup"]
+            project_ref = project_ref_dict["ProjectRef"]
+
+        self._SetUpProductReferences(other_pbxproject, product_group, project_ref)
+
+        inherit_unique_symroot = self._AllSymrootsUnique(other_pbxproject, False)
+        targets = other_pbxproject.GetProperty("targets")
+        if all(self._AllSymrootsUnique(t, inherit_unique_symroot) for t in targets):
+            dir_path = project_ref._properties["path"]
+            product_group._hashables.extend(dir_path)
+
+        return [product_group, project_ref]
+
+    def _AllSymrootsUnique(self, target, inherit_unique_symroot):
+        # Returns True if all configurations have a unique 'SYMROOT' attribute.
+        # The value of inherit_unique_symroot decides, if a configuration is assumed
+        # to inherit a unique 'SYMROOT' attribute from its parent, if it doesn't
+        # define an explicit value for 'SYMROOT'.
+        symroots = self._DefinedSymroots(target)
+        for s in self._DefinedSymroots(target):
+            if (
+                s is not None
+                and not self._IsUniqueSymrootForTarget(s)
+                or s is None
+                and not inherit_unique_symroot
+            ):
+                return False
+        return True if symroots else inherit_unique_symroot
+
+    def _DefinedSymroots(self, target):
+        # Returns all values for the 'SYMROOT' attribute defined in all
+        # configurations for this target. If any configuration doesn't define the
+        # 'SYMROOT' attribute, None is added to the returned set. If all
+        # configurations don't define the 'SYMROOT' attribute, an empty set is
+        # returned.
+        config_list = target.GetProperty("buildConfigurationList")
+        symroots = set()
+        for config in config_list.GetProperty("buildConfigurations"):
+            setting = config.GetProperty("buildSettings")
+            if "SYMROOT" in setting:
+                symroots.add(setting["SYMROOT"])
+            else:
+                symroots.add(None)
+        if len(symroots) == 1 and None in symroots:
+            return set()
+        return symroots
+
+    def _IsUniqueSymrootForTarget(self, symroot):
+        # This method returns True if all configurations in target contain a
+        # 'SYMROOT' attribute that is unique for the given target. A value is
+        # unique, if the Xcode macro '$SRCROOT' appears in it in any form.
+        uniquifier = ["$SRCROOT", "$(SRCROOT)"]
+        if any(x in symroot for x in uniquifier):
+            return True
+        return False
+
+    def _SetUpProductReferences(self, other_pbxproject, product_group, project_ref):
+        # TODO(mark): This only adds references to products in other_pbxproject
+        # when they don't exist in this pbxproject.  Perhaps it should also
+        # remove references from this pbxproject that are no longer present in
+        # other_pbxproject.  Perhaps it should update various properties if they
+        # change.
+        for target in other_pbxproject._properties["targets"]:
+            if not isinstance(target, PBXNativeTarget):
+                continue
+
+            other_fileref = target._properties["productReference"]
+            if product_group.GetChildByRemoteObject(other_fileref) is None:
+                # Xcode sets remoteInfo to the name of the target and not the name
+                # of its product, despite this proxy being a reference to the product.
+                container_item = PBXContainerItemProxy(
+                    {
+                        "containerPortal": project_ref,
+                        "proxyType": 2,
+                        "remoteGlobalIDString": other_fileref,
+                        "remoteInfo": target.Name(),
+                    }
+                )
+                # TODO(mark): Does sourceTree get copied straight over from the other
+                # project?  Can the other project ever have lastKnownFileType here
+                # instead of explicitFileType?  (Use it if so?)  Can path ever be
+                # unset?  (I don't think so.)  Can other_fileref have name set, and
+                # does it impact the PBXReferenceProxy if so?  These are the questions
+                # that perhaps will be answered one day.
+                reference_proxy = PBXReferenceProxy(
+                    {
+                        "fileType": other_fileref._properties["explicitFileType"],
+                        "path": other_fileref._properties["path"],
+                        "sourceTree": other_fileref._properties["sourceTree"],
+                        "remoteRef": container_item,
+                    }
+                )
+
+                product_group.AppendChild(reference_proxy)
+
+    def SortRemoteProductReferences(self):
+        # For each remote project file, sort the associated ProductGroup in the
+        # same order that the targets are sorted in the remote project file.  This
+        # is the sort order used by Xcode.
+
+        def CompareProducts(x, y, remote_products):
+            # x and y are PBXReferenceProxy objects.  Go through their associated
+            # PBXContainerItem to get the remote PBXFileReference, which will be
+            # present in the remote_products list.
+            x_remote = x._properties["remoteRef"]._properties["remoteGlobalIDString"]
+            y_remote = y._properties["remoteRef"]._properties["remoteGlobalIDString"]
+            x_index = remote_products.index(x_remote)
+            y_index = remote_products.index(y_remote)
+
+            # Use the order of each remote PBXFileReference in remote_products to
+            # determine the sort order.
+            return cmp(x_index, y_index)
+
+        for other_pbxproject, ref_dict in self._other_pbxprojects.items():
+            # Build up a list of products in the remote project file, ordered the
+            # same as the targets that produce them.
+            remote_products = []
+            for target in other_pbxproject._properties["targets"]:
+                if not isinstance(target, PBXNativeTarget):
+                    continue
+                remote_products.append(target._properties["productReference"])
+
+            # Sort the PBXReferenceProxy children according to the list of remote
+            # products.
+            product_group = ref_dict["ProductGroup"]
+            product_group._properties["children"] = sorted(
+                product_group._properties["children"],
+                key=cmp_to_key(
+                    lambda x, y, rp=remote_products: CompareProducts(x, y, rp)),
+            )
+
+
+class XCProjectFile(XCObject):
+    _schema = XCObject._schema.copy()
+    _schema.update(
+        {
+            "archiveVersion": [0, int, 0, 1, 1],
+            "classes": [0, dict, 0, 1, {}],
+            "objectVersion": [0, int, 0, 1, 46],
+            "rootObject": [0, PBXProject, 1, 1],
+        }
+    )
+
+    def ComputeIDs(self, recursive=True, overwrite=True, hash=None):
+        # Although XCProjectFile is implemented here as an XCObject, it's not a
+        # proper object in the Xcode sense, and it certainly doesn't have its own
+        # ID.  Pass through an attempt to update IDs to the real root object.
+        if recursive:
+            self._properties["rootObject"].ComputeIDs(recursive, overwrite, hash)
+
+    def Print(self, file=sys.stdout):
+        self.VerifyHasRequiredProperties()
+
+        # Add the special "objects" property, which will be caught and handled
+        # separately during printing.  This structure allows a fairly standard
+        # loop do the normal printing.
+        self._properties["objects"] = {}
+        self._XCPrint(file, 0, "// !$*UTF8*$!\n")
+        if self._should_print_single_line:
+            self._XCPrint(file, 0, "{ ")
+        else:
+            self._XCPrint(file, 0, "{\n")
+        for property, value in sorted(
+            self._properties.items()
+        ):
+            if property == "objects":
+                self._PrintObjects(file)
+            else:
+                self._XCKVPrint(file, 1, property, value)
+        self._XCPrint(file, 0, "}\n")
+        del self._properties["objects"]
+
+    def _PrintObjects(self, file):
+        if self._should_print_single_line:
+            self._XCPrint(file, 0, "objects = {")
+        else:
+            self._XCPrint(file, 1, "objects = {\n")
+
+        objects_by_class = {}
+        for object in self.Descendants():
+            if object == self:
+                continue
+            class_name = object.__class__.__name__
+            if class_name not in objects_by_class:
+                objects_by_class[class_name] = []
+            objects_by_class[class_name].append(object)
+
+        for class_name in sorted(objects_by_class):
+            self._XCPrint(file, 0, "\n")
+            self._XCPrint(file, 0, "/* Begin " + class_name + " section */\n")
+            for object in sorted(
+                objects_by_class[class_name], key=attrgetter("id")
+            ):
+                object.Print(file)
+            self._XCPrint(file, 0, "/* End " + class_name + " section */\n")
+
+        if self._should_print_single_line:
+            self._XCPrint(file, 0, "}; ")
+        else:
+            self._XCPrint(file, 1, "};\n")
diff --git a/server/node_modules/node-gyp/gyp/pylib/gyp/xml_fix.py b/server/node_modules/node-gyp/gyp/pylib/gyp/xml_fix.py
new file mode 100644
index 0000000..5301963
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/pylib/gyp/xml_fix.py
@@ -0,0 +1,65 @@
+# Copyright (c) 2011 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Applies a fix to CR LF TAB handling in xml.dom.
+
+Fixes this: http://code.google.com/p/chromium/issues/detail?id=76293
+Working around this: http://bugs.python.org/issue5752
+TODO(bradnelson): Consider dropping this when we drop XP support.
+"""
+
+
+import xml.dom.minidom
+
+
+def _Replacement_write_data(writer, data, is_attrib=False):
+    """Writes datachars to writer."""
+    data = data.replace("&", "&").replace("<", "<")
+    data = data.replace('"', """).replace(">", ">")
+    if is_attrib:
+        data = data.replace("\r", "").replace("\n", "
").replace("\t", "	")
+    writer.write(data)
+
+
+def _Replacement_writexml(self, writer, indent="", addindent="", newl=""):
+    # indent = current indentation
+    # addindent = indentation to add to higher levels
+    # newl = newline string
+    writer.write(indent + "<" + self.tagName)
+
+    attrs = self._get_attributes()
+    a_names = sorted(attrs.keys())
+
+    for a_name in a_names:
+        writer.write(' %s="' % a_name)
+        _Replacement_write_data(writer, attrs[a_name].value, is_attrib=True)
+        writer.write('"')
+    if self.childNodes:
+        writer.write(">%s" % newl)
+        for node in self.childNodes:
+            node.writexml(writer, indent + addindent, addindent, newl)
+        writer.write(f"{indent}</{self.tagName}>{newl}")
+    else:
+        writer.write("/>%s" % newl)
+
+
+class XmlFix:
+    """Object to manage temporary patching of xml.dom.minidom."""
+
+    def __init__(self):
+        # Preserve current xml.dom.minidom functions.
+        self.write_data = xml.dom.minidom._write_data
+        self.writexml = xml.dom.minidom.Element.writexml
+        # Inject replacement versions of a function and a method.
+        xml.dom.minidom._write_data = _Replacement_write_data
+        xml.dom.minidom.Element.writexml = _Replacement_writexml
+
+    def Cleanup(self):
+        if self.write_data:
+            xml.dom.minidom._write_data = self.write_data
+            xml.dom.minidom.Element.writexml = self.writexml
+            self.write_data = None
+
+    def __del__(self):
+        self.Cleanup()
diff --git a/server/node_modules/node-gyp/gyp/requirements_dev.txt b/server/node_modules/node-gyp/gyp/requirements_dev.txt
new file mode 100644
index 0000000..28ecaca
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/requirements_dev.txt
@@ -0,0 +1,2 @@
+flake8
+pytest
diff --git a/server/node_modules/node-gyp/gyp/setup.py b/server/node_modules/node-gyp/gyp/setup.py
new file mode 100644
index 0000000..cf9d7d2
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/setup.py
@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2009 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from os import path
+
+from setuptools import setup
+
+here = path.abspath(path.dirname(__file__))
+# Get the long description from the README file
+with open(path.join(here, "README.md")) as in_file:
+    long_description = in_file.read()
+
+setup(
+    name="gyp-next",
+    version="0.10.0",
+    description="A fork of the GYP build system for use in the Node.js projects",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
+    author="Node.js contributors",
+    author_email="ryzokuken@disroot.org",
+    url="https://github.com/nodejs/gyp-next",
+    package_dir={"": "pylib"},
+    packages=["gyp", "gyp.generator"],
+    entry_points={"console_scripts": ["gyp=gyp:script_main"]},
+    python_requires=">=3.6",
+    classifiers=[
+        "Development Status :: 3 - Alpha",
+        "Environment :: Console",
+        "Intended Audience :: Developers",
+        "License :: OSI Approved :: BSD License",
+        "Natural Language :: English",
+        "Programming Language :: Python",
+        "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+    ],
+)
diff --git a/server/node_modules/node-gyp/gyp/test_gyp.py b/server/node_modules/node-gyp/gyp/test_gyp.py
new file mode 100755
index 0000000..9ba2641
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/test_gyp.py
@@ -0,0 +1,260 @@
+#!/usr/bin/env python3
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""gyptest.py -- test runner for GYP tests."""
+
+
+import argparse
+import os
+import platform
+import subprocess
+import sys
+import time
+
+
+def is_test_name(f):
+    return f.startswith("gyptest") and f.endswith(".py")
+
+
+def find_all_gyptest_files(directory):
+    result = []
+    for root, dirs, files in os.walk(directory):
+        result.extend([os.path.join(root, f) for f in files if is_test_name(f)])
+    result.sort()
+    return result
+
+
+def main(argv=None):
+    if argv is None:
+        argv = sys.argv
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-a", "--all", action="store_true", help="run all tests")
+    parser.add_argument("-C", "--chdir", action="store", help="change to directory")
+    parser.add_argument(
+        "-f",
+        "--format",
+        action="store",
+        default="",
+        help="run tests with the specified formats",
+    )
+    parser.add_argument(
+        "-G",
+        "--gyp_option",
+        action="append",
+        default=[],
+        help="Add -G options to the gyp command line",
+    )
+    parser.add_argument(
+        "-l", "--list", action="store_true", help="list available tests and exit"
+    )
+    parser.add_argument(
+        "-n",
+        "--no-exec",
+        action="store_true",
+        help="no execute, just print the command line",
+    )
+    parser.add_argument(
+        "--path", action="append", default=[], help="additional $PATH directory"
+    )
+    parser.add_argument(
+        "-q",
+        "--quiet",
+        action="store_true",
+        help="quiet, don't print anything unless there are failures",
+    )
+    parser.add_argument(
+        "-v",
+        "--verbose",
+        action="store_true",
+        help="print configuration info and test results.",
+    )
+    parser.add_argument("tests", nargs="*")
+    args = parser.parse_args(argv[1:])
+
+    if args.chdir:
+        os.chdir(args.chdir)
+
+    if args.path:
+        extra_path = [os.path.abspath(p) for p in args.path]
+        extra_path = os.pathsep.join(extra_path)
+        os.environ["PATH"] = extra_path + os.pathsep + os.environ["PATH"]
+
+    if not args.tests:
+        if not args.all:
+            sys.stderr.write("Specify -a to get all tests.\n")
+            return 1
+        args.tests = ["test"]
+
+    tests = []
+    for arg in args.tests:
+        if os.path.isdir(arg):
+            tests.extend(find_all_gyptest_files(os.path.normpath(arg)))
+        else:
+            if not is_test_name(os.path.basename(arg)):
+                print(arg, "is not a valid gyp test name.", file=sys.stderr)
+                sys.exit(1)
+            tests.append(arg)
+
+    if args.list:
+        for test in tests:
+            print(test)
+        sys.exit(0)
+
+    os.environ["PYTHONPATH"] = os.path.abspath("test/lib")
+
+    if args.verbose:
+        print_configuration_info()
+
+    if args.gyp_option and not args.quiet:
+        print("Extra Gyp options: %s\n" % args.gyp_option)
+
+    if args.format:
+        format_list = args.format.split(",")
+    else:
+        format_list = {
+            "aix5": ["make"],
+            "freebsd7": ["make"],
+            "freebsd8": ["make"],
+            "openbsd5": ["make"],
+            "cygwin": ["msvs"],
+            "win32": ["msvs", "ninja"],
+            "linux": ["make", "ninja"],
+            "linux2": ["make", "ninja"],
+            "linux3": ["make", "ninja"],
+            # TODO: Re-enable xcode-ninja.
+            # https://bugs.chromium.org/p/gyp/issues/detail?id=530
+            # 'darwin':   ['make', 'ninja', 'xcode', 'xcode-ninja'],
+            "darwin": ["make", "ninja", "xcode"],
+        }[sys.platform]
+
+    gyp_options = []
+    for option in args.gyp_option:
+        gyp_options += ["-G", option]
+
+    runner = Runner(format_list, tests, gyp_options, args.verbose)
+    runner.run()
+
+    if not args.quiet:
+        runner.print_results()
+
+    return 1 if runner.failures else 0
+
+
+def print_configuration_info():
+    print("Test configuration:")
+    if sys.platform == "darwin":
+        sys.path.append(os.path.abspath("test/lib"))
+        import TestMac
+
+        print(f"  Mac {platform.mac_ver()[0]} {platform.mac_ver()[2]}")
+        print(f"  Xcode {TestMac.Xcode.Version()}")
+    elif sys.platform == "win32":
+        sys.path.append(os.path.abspath("pylib"))
+        import gyp.MSVSVersion
+
+        print("  Win %s %s\n" % platform.win32_ver()[0:2])
+        print("  MSVS %s" % gyp.MSVSVersion.SelectVisualStudioVersion().Description())
+    elif sys.platform in ("linux", "linux2"):
+        print("  Linux %s" % " ".join(platform.linux_distribution()))
+    print(f"  Python {platform.python_version()}")
+    print(f"  PYTHONPATH={os.environ['PYTHONPATH']}")
+    print()
+
+
+class Runner:
+    def __init__(self, formats, tests, gyp_options, verbose):
+        self.formats = formats
+        self.tests = tests
+        self.verbose = verbose
+        self.gyp_options = gyp_options
+        self.failures = []
+        self.num_tests = len(formats) * len(tests)
+        num_digits = len(str(self.num_tests))
+        self.fmt_str = "[%%%dd/%%%dd] (%%s) %%s" % (num_digits, num_digits)
+        self.isatty = sys.stdout.isatty() and not self.verbose
+        self.env = os.environ.copy()
+        self.hpos = 0
+
+    def run(self):
+        run_start = time.time()
+
+        i = 1
+        for fmt in self.formats:
+            for test in self.tests:
+                self.run_test(test, fmt, i)
+                i += 1
+
+        if self.isatty:
+            self.erase_current_line()
+
+        self.took = time.time() - run_start
+
+    def run_test(self, test, fmt, i):
+        if self.isatty:
+            self.erase_current_line()
+
+        msg = self.fmt_str % (i, self.num_tests, fmt, test)
+        self.print_(msg)
+
+        start = time.time()
+        cmd = [sys.executable, test] + self.gyp_options
+        self.env["TESTGYP_FORMAT"] = fmt
+        proc = subprocess.Popen(
+            cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, env=self.env
+        )
+        proc.wait()
+        took = time.time() - start
+
+        stdout = proc.stdout.read().decode("utf8")
+        if proc.returncode == 2:
+            res = "skipped"
+        elif proc.returncode:
+            res = "failed"
+            self.failures.append(f"({test}) {fmt}")
+        else:
+            res = "passed"
+        res_msg = f" {res} {took:.3f}s"
+        self.print_(res_msg)
+
+        if stdout and not stdout.endswith(("PASSED\n", "NO RESULT\n")):
+            print()
+            print("\n".join(f"    {line}" for line in stdout.splitlines()))
+        elif not self.isatty:
+            print()
+
+    def print_(self, msg):
+        print(msg, end="")
+        index = msg.rfind("\n")
+        if index == -1:
+            self.hpos += len(msg)
+        else:
+            self.hpos = len(msg) - index
+        sys.stdout.flush()
+
+    def erase_current_line(self):
+        print("\b" * self.hpos + " " * self.hpos + "\b" * self.hpos, end="")
+        sys.stdout.flush()
+        self.hpos = 0
+
+    def print_results(self):
+        num_failures = len(self.failures)
+        if num_failures:
+            print()
+            if num_failures == 1:
+                print("Failed the following test:")
+            else:
+                print("Failed the following %d tests:" % num_failures)
+            print("\t" + "\n\t".join(sorted(self.failures)))
+            print()
+        print(
+            "Ran %d tests in %.3fs, %d failed."
+            % (self.num_tests, self.took, num_failures)
+        )
+        print()
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/server/node_modules/node-gyp/gyp/tools/README b/server/node_modules/node-gyp/gyp/tools/README
new file mode 100644
index 0000000..84a73d1
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/README
@@ -0,0 +1,15 @@
+pretty_vcproj:
+  Usage: pretty_vcproj.py "c:\path\to\vcproj.vcproj" [key1=value1] [key2=value2]
+
+  They key/value pair are used to resolve vsprops name.
+
+  For example, if I want to diff the base.vcproj project:
+
+  pretty_vcproj.py z:\dev\src-chrome\src\base\build\base.vcproj "$(SolutionDir)=z:\dev\src-chrome\src\chrome\\" "$(CHROMIUM_BUILD)=" "$(CHROME_BUILD_TYPE)=" > original.txt
+  pretty_vcproj.py z:\dev\src-chrome\src\base\base_gyp.vcproj "$(SolutionDir)=z:\dev\src-chrome\src\chrome\\" "$(CHROMIUM_BUILD)=" "$(CHROME_BUILD_TYPE)=" > gyp.txt
+
+  And you can use your favorite diff tool to see the changes.
+
+  Note: In the case of base.vcproj, the original vcproj is one level up the generated one.
+        I suggest you do a search and replace for '"..\' and replace it with '"' in original.txt
+        before you perform the diff.
\ No newline at end of file
diff --git a/server/node_modules/node-gyp/gyp/tools/Xcode/README b/server/node_modules/node-gyp/gyp/tools/Xcode/README
new file mode 100644
index 0000000..2492a2c
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/Xcode/README
@@ -0,0 +1,5 @@
+Specifications contains syntax formatters for Xcode 3. These do not appear to be supported yet on Xcode 4. To use these with Xcode 3 please install both the gyp.pbfilespec and gyp.xclangspec files in
+
+~/Library/Application Support/Developer/Shared/Xcode/Specifications/
+
+and restart Xcode.
\ No newline at end of file
diff --git a/server/node_modules/node-gyp/gyp/tools/Xcode/Specifications/gyp.pbfilespec b/server/node_modules/node-gyp/gyp/tools/Xcode/Specifications/gyp.pbfilespec
new file mode 100644
index 0000000..85e2e26
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/Xcode/Specifications/gyp.pbfilespec
@@ -0,0 +1,27 @@
+/*
+	gyp.pbfilespec
+	GYP source file spec for Xcode 3
+
+	There is not much documentation available regarding the format
+	of .pbfilespec files. As a starting point, see for instance the
+	outdated documentation at:
+	http://maxao.free.fr/xcode-plugin-interface/specifications.html
+	and the files in:
+	/Developer/Library/PrivateFrameworks/XcodeEdit.framework/Versions/A/Resources/
+
+	Place this file in directory:
+	~/Library/Application Support/Developer/Shared/Xcode/Specifications/
+*/
+
+(
+	{
+		Identifier = sourcecode.gyp;
+		BasedOn = sourcecode;
+		Name = "GYP Files";
+		Extensions = ("gyp", "gypi");
+		MIMETypes = ("text/gyp");
+		Language = "xcode.lang.gyp";
+		IsTextFile = YES;
+		IsSourceFile = YES;
+	}
+)
diff --git a/server/node_modules/node-gyp/gyp/tools/Xcode/Specifications/gyp.xclangspec b/server/node_modules/node-gyp/gyp/tools/Xcode/Specifications/gyp.xclangspec
new file mode 100644
index 0000000..3b3506d
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/Xcode/Specifications/gyp.xclangspec
@@ -0,0 +1,226 @@
+/*
+	Copyright (c) 2011 Google Inc. All rights reserved.
+	Use of this source code is governed by a BSD-style license that can be
+	found in the LICENSE file.
+	
+	gyp.xclangspec
+	GYP language specification for Xcode 3
+
+	There is not much documentation available regarding the format
+	of .xclangspec files. As a starting point, see for instance the
+	outdated documentation at:
+	http://maxao.free.fr/xcode-plugin-interface/specifications.html
+	and the files in:
+	/Developer/Library/PrivateFrameworks/XcodeEdit.framework/Versions/A/Resources/
+
+	Place this file in directory:
+	~/Library/Application Support/Developer/Shared/Xcode/Specifications/
+*/
+
+(
+
+    {
+        Identifier = "xcode.lang.gyp.keyword";
+        Syntax = {
+            Words = (
+                "and",
+                "or",
+                "<!",
+                "<",
+             );
+            Type = "xcode.syntax.keyword";
+        };
+    },
+
+    {
+        Identifier = "xcode.lang.gyp.target.declarator";
+        Syntax = {
+        	Words = (
+        		"'target_name'",
+        	);
+            Type = "xcode.syntax.identifier.type";
+        };
+    },
+
+	{
+		Identifier = "xcode.lang.gyp.string.singlequote";
+		Syntax = {
+			IncludeRules = (
+				"xcode.lang.string",
+				"xcode.lang.gyp.keyword",
+				"xcode.lang.number",
+			);
+			Start = "'";
+			End = "'";
+		};
+	},
+	
+	{
+		Identifier = "xcode.lang.gyp.comma";
+		Syntax = {
+			Words = ( ",", );
+			
+		};
+	},
+
+	{
+		Identifier = "xcode.lang.gyp";
+		Description = "GYP Coloring";
+		BasedOn = "xcode.lang.simpleColoring";
+		IncludeInMenu = YES;
+		Name = "GYP";
+		Syntax = {
+			Tokenizer = "xcode.lang.gyp.lexer.toplevel";
+			IncludeRules = (
+				"xcode.lang.gyp.dictionary",
+			);
+			Type = "xcode.syntax.plain";
+		};
+	},
+
+	// The following rule returns tokens to the other rules
+	{
+		Identifier = "xcode.lang.gyp.lexer";
+		Syntax = {
+			IncludeRules = (
+				"xcode.lang.gyp.comment",
+				"xcode.lang.string",
+				'xcode.lang.gyp.targetname.declarator',
+				"xcode.lang.gyp.string.singlequote",
+				"xcode.lang.number",
+				"xcode.lang.gyp.comma",
+			);
+		};
+	},
+
+	{
+		Identifier = "xcode.lang.gyp.lexer.toplevel";
+		Syntax = {
+			IncludeRules = (
+				"xcode.lang.gyp.comment",
+			);
+		};
+	},
+
+	{
+        Identifier = "xcode.lang.gyp.assignment";
+        Syntax = {
+            Tokenizer = "xcode.lang.gyp.lexer";
+            Rules = (
+            	"xcode.lang.gyp.assignment.lhs",
+            	":",
+                "xcode.lang.gyp.assignment.rhs",
+            );
+        };
+       
+    },
+    
+    {
+        Identifier = "xcode.lang.gyp.target.declaration";
+        Syntax = {
+            Tokenizer = "xcode.lang.gyp.lexer";
+            Rules = (
+                "xcode.lang.gyp.target.declarator",
+                ":",
+                "xcode.lang.gyp.target.name",
+            );
+        };
+   },
+   
+   {
+        Identifier = "xcode.lang.gyp.target.name";
+        Syntax = {
+            Tokenizer = "xcode.lang.gyp.lexer";
+            Rules = (
+                "xcode.lang.gyp.string.singlequote",
+            );
+        	Type = "xcode.syntax.definition.function";
+        };
+    },
+    
+	{
+        Identifier = "xcode.lang.gyp.assignment.lhs";
+        Syntax = {
+            Tokenizer = "xcode.lang.gyp.lexer";
+            Rules = (
+            	"xcode.lang.gyp.string.singlequote",
+            );
+         	Type = "xcode.syntax.identifier.type";
+        };
+    },
+    
+    {
+        Identifier = "xcode.lang.gyp.assignment.rhs";
+        Syntax = {
+        	Tokenizer = "xcode.lang.gyp.lexer";
+            Rules = (
+            	"xcode.lang.gyp.string.singlequote?",
+                "xcode.lang.gyp.array?",
+				"xcode.lang.gyp.dictionary?",
+				"xcode.lang.number?",
+            );
+        };
+    },
+
+	{
+		Identifier = "xcode.lang.gyp.dictionary";
+		Syntax = {
+			Tokenizer = "xcode.lang.gyp.lexer";
+			Start = "{";
+			End = "}";
+			Foldable = YES;
+			Recursive = YES;
+			IncludeRules = (
+				"xcode.lang.gyp.target.declaration",
+				"xcode.lang.gyp.assignment",
+			);
+		};
+	},
+
+	{
+		Identifier = "xcode.lang.gyp.array";
+		Syntax = {
+			Tokenizer = "xcode.lang.gyp.lexer";
+			Start = "[";
+			End = "]";
+			Foldable = YES;
+			Recursive = YES;
+			IncludeRules = (
+				"xcode.lang.gyp.array",
+				"xcode.lang.gyp.dictionary",
+				"xcode.lang.gyp.string.singlequote",
+			);
+		};
+	},
+
+    {
+        Identifier = "xcode.lang.gyp.todo.mark";
+        Syntax = {
+            StartChars = "T";
+            Match = (
+                "^$TODO\(.*$:[ \t]+.*\)$",       // include "TODO: " in the markers list
+            );
+            // This is the order of captures. All of the match strings above need the same order.
+            CaptureTypes = (
+                "xcode.syntax.mark"
+            );
+            Type = "xcode.syntax.comment";
+        };
+    },
+
+	{
+		Identifier = "xcode.lang.gyp.comment";
+		BasedOn = "xcode.lang.comment"; // for text macros
+		Syntax = {
+			Start = "#";
+			End = "\n";
+			IncludeRules = (
+				"xcode.lang.url",
+				"xcode.lang.url.mail",
+				"xcode.lang.comment.mark",
+				"xcode.lang.gyp.todo.mark",
+			);
+			Type = "xcode.syntax.comment";
+		};
+	},
+)
diff --git a/server/node_modules/node-gyp/gyp/tools/emacs/README b/server/node_modules/node-gyp/gyp/tools/emacs/README
new file mode 100644
index 0000000..eeef39f
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/emacs/README
@@ -0,0 +1,12 @@
+How to install gyp-mode for emacs:
+
+Add the following to your ~/.emacs (replace ... with the path to your gyp
+checkout).
+
+(setq load-path (cons ".../tools/emacs" load-path))
+(require 'gyp)
+
+Restart emacs (or eval-region the added lines) and you should be all set.
+
+Please note that ert is required for running the tests, which is included in
+Emacs 24, or available separately from https://github.com/ohler/ert
diff --git a/server/node_modules/node-gyp/gyp/tools/emacs/gyp-tests.el b/server/node_modules/node-gyp/gyp/tools/emacs/gyp-tests.el
new file mode 100644
index 0000000..07afc58
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/emacs/gyp-tests.el
@@ -0,0 +1,63 @@
+;;; gyp-tests.el - unit tests for gyp-mode.
+
+;; Copyright (c) 2012 Google Inc. All rights reserved.
+;; Use of this source code is governed by a BSD-style license that can be
+;; found in the LICENSE file.
+
+;; The recommended way to run these tests is to run them from the command-line,
+;; with the run-unit-tests.sh script.
+
+(require 'cl)
+(require 'ert)
+(require 'gyp)
+
+(defconst samples (directory-files "testdata" t ".gyp$")
+  "List of golden samples to check")
+
+(defun fontify (filename)
+  (with-temp-buffer
+    (insert-file-contents-literally filename)
+    (gyp-mode)
+    (font-lock-fontify-buffer)
+    (buffer-string)))
+
+(defun read-golden-sample (filename)
+  (with-temp-buffer
+    (insert-file-contents-literally (concat filename ".fontified"))
+    (read (current-buffer))))
+
+(defun equivalent-face (face)
+  "For the purposes of face comparison, we're not interested in the
+   differences between certain faces. For example, the difference between
+   font-lock-comment-delimiter and font-lock-comment-face."
+  (cl-case face
+    ((font-lock-comment-delimiter-face) font-lock-comment-face)
+    (t face)))
+
+(defun text-face-properties (s)
+  "Extract the text properties from s"
+  (let ((result (list t)))
+    (dotimes (i (length s))
+      (setq result (cons (equivalent-face (get-text-property i 'face s))
+                         result)))
+    (nreverse result)))
+
+(ert-deftest test-golden-samples ()
+  "Check that fontification produces the same results as the golden samples"
+  (dolist (sample samples)
+    (let ((golden (read-golden-sample sample))
+          (fontified (fontify sample)))
+      (should (equal golden fontified))
+      (should (equal (text-face-properties golden)
+                     (text-face-properties fontified))))))
+
+(defun create-golden-sample (filename)
+  "Create a golden sample by fontifying filename and writing out the printable
+   representation of the fontified buffer (with text properties) to the
+   FILENAME.fontified"
+  (with-temp-file (concat filename ".fontified")
+    (print (fontify filename) (current-buffer))))
+
+(defun create-golden-samples ()
+  "Recreate the golden samples"
+  (dolist (sample samples) (create-golden-sample sample)))
diff --git a/server/node_modules/node-gyp/gyp/tools/emacs/gyp.el b/server/node_modules/node-gyp/gyp/tools/emacs/gyp.el
new file mode 100644
index 0000000..042ff3a
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/emacs/gyp.el
@@ -0,0 +1,275 @@
+;;; gyp.el - font-lock-mode support for gyp files.
+
+;; Copyright (c) 2012 Google Inc. All rights reserved.
+;; Use of this source code is governed by a BSD-style license that can be
+;; found in the LICENSE file.
+
+;; Put this somewhere in your load-path and
+;; (require 'gyp)
+
+(require 'python)
+(require 'cl)
+
+(when (string-match "python-mode.el" (symbol-file 'python-mode 'defun))
+  (error (concat "python-mode must be loaded from python.el (bundled with "
+                 "recent emacsen), not from the older and less maintained "
+                 "python-mode.el")))
+
+(defadvice python-indent-calculate-levels (after gyp-outdent-closing-parens
+                                                 activate)
+  "De-indent closing parens, braces, and brackets in gyp-mode."
+  (when (and (eq major-mode 'gyp-mode)
+             (string-match "^ *[])}][],)}]* *$"
+                           (buffer-substring-no-properties
+                            (line-beginning-position) (line-end-position))))
+    (setf (first python-indent-levels)
+          (- (first python-indent-levels) python-continuation-offset))))
+
+(defadvice python-indent-guess-indent-offset (around
+                                              gyp-indent-guess-indent-offset
+                                              activate)
+  "Guess correct indent offset in gyp-mode."
+  (or (and (not (eq major-mode 'gyp-mode))
+           ad-do-it)
+      (save-excursion
+        (save-restriction
+          (widen)
+          (goto-char (point-min))
+          ;; Find first line ending with an opening brace that is not a comment.
+          (or (and (re-search-forward "\$^[[{]$\\|^.*[^#].*[[{]$\$")
+                   (forward-line)
+                   (/= (current-indentation) 0)
+                   (set (make-local-variable 'python-indent-offset)
+                        (current-indentation))
+                   (set (make-local-variable 'python-continuation-offset)
+                        (current-indentation)))
+              (message "Can't guess gyp indent offset, using default: %s"
+                       python-continuation-offset))))))
+
+(define-derived-mode gyp-mode python-mode "Gyp"
+  "Major mode for editing .gyp files. See http://code.google.com/p/gyp/"
+  ;; gyp-parse-history is a stack of (POSITION . PARSE-STATE) tuples,
+  ;; with greater positions at the top of the stack. PARSE-STATE
+  ;; is a list of section symbols (see gyp-section-name and gyp-parse-to)
+  ;; with most nested section symbol at the front of the list.
+  (set (make-local-variable 'gyp-parse-history) '((1 . (list))))
+  (gyp-add-font-lock-keywords))
+
+(defun gyp-set-indentation ()
+  "Hook function to configure python indentation to suit gyp mode."
+  (set (make-local-variable 'python-indent-offset) 2)
+  (set (make-local-variable 'python-continuation-offset) 2)
+  (set (make-local-variable 'python-indent-guess-indent-offset) t)
+  (python-indent-guess-indent-offset))
+
+(add-hook 'gyp-mode-hook 'gyp-set-indentation)
+
+(add-to-list 'auto-mode-alist '("\\.gyp\\'" . gyp-mode))
+(add-to-list 'auto-mode-alist '("\\.gypi\\'" . gyp-mode))
+(add-to-list 'auto-mode-alist '("/\\.gclient\\'" . gyp-mode))
+
+;;; Font-lock support
+
+(defconst gyp-dependencies-regexp
+  (regexp-opt (list "dependencies" "export_dependent_settings"))
+  "Regular expression to introduce 'dependencies' section")
+
+(defconst gyp-sources-regexp
+  (regexp-opt (list "action" "files" "include_dirs" "includes" "inputs"
+                    "libraries" "outputs" "sources"))
+  "Regular expression to introduce 'sources' sections")
+
+(defconst gyp-conditions-regexp
+  (regexp-opt (list "conditions" "target_conditions"))
+  "Regular expression to introduce conditions sections")
+
+(defconst gyp-variables-regexp
+  "^variables"
+  "Regular expression to introduce variables sections")
+
+(defconst gyp-defines-regexp
+  "^defines"
+  "Regular expression to introduce 'defines' sections")
+
+(defconst gyp-targets-regexp
+  "^targets"
+  "Regular expression to introduce 'targets' sections")
+
+(defun gyp-section-name (section)
+  "Map the sections we are interested in from SECTION to symbol.
+
+   SECTION is a string from the buffer that introduces a section.  The result is
+   a symbol representing the kind of section.
+
+   This allows us to treat (for the purposes of font-lock) several different
+   section names as the same kind of section. For example, a 'sources section
+   can be introduced by the 'sources', 'inputs', 'outputs' keyword.
+
+   'other is the default section kind when a more specific match is not made."
+  (cond ((string-match-p gyp-dependencies-regexp section) 'dependencies)
+        ((string-match-p gyp-sources-regexp section) 'sources)
+        ((string-match-p gyp-variables-regexp section) 'variables)
+        ((string-match-p gyp-conditions-regexp section) 'conditions)
+        ((string-match-p gyp-targets-regexp section) 'targets)
+        ((string-match-p gyp-defines-regexp section) 'defines)
+        (t 'other)))
+
+(defun gyp-invalidate-parse-states-after (target-point)
+  "Erase any parse information after target-point."
+  (while (> (caar gyp-parse-history) target-point)
+    (setq gyp-parse-history (cdr gyp-parse-history))))
+
+(defun gyp-parse-point ()
+  "The point of the last parse state added by gyp-parse-to."
+  (caar gyp-parse-history))
+
+(defun gyp-parse-sections ()
+  "A list of section symbols holding at the last parse state point."
+  (cdar gyp-parse-history))
+
+(defun gyp-inside-dictionary-p ()
+  "Predicate returning true if the parser is inside a dictionary."
+  (not (eq (cadar gyp-parse-history) 'list)))
+
+(defun gyp-add-parse-history (point sections)
+  "Add parse state SECTIONS to the parse history at POINT so that parsing can be
+   resumed instantly."
+  (while (>= (caar gyp-parse-history) point)
+    (setq gyp-parse-history (cdr gyp-parse-history)))
+  (setq gyp-parse-history (cons (cons point sections) gyp-parse-history)))
+
+(defun gyp-parse-to (target-point)
+  "Parses from (point) to TARGET-POINT adding the parse state information to
+   gyp-parse-state-history. Parsing stops if TARGET-POINT is reached or if a
+   string literal has been parsed. Returns nil if no further parsing can be
+   done, otherwise returns the position of the start of a parsed string, leaving
+   the point at the end of the string."
+  (let ((parsing t)
+        string-start)
+    (while parsing
+      (setq string-start nil)
+      ;; Parse up to a character that starts a sexp, or if the nesting
+      ;; level decreases.
+      (let ((state (parse-partial-sexp (gyp-parse-point)
+                                       target-point
+                                       -1
+                                       t))
+            (sections (gyp-parse-sections)))
+        (if (= (nth 0 state) -1)
+            (setq sections (cdr sections)) ; pop out a level
+          (cond ((looking-at-p "['\"]") ; a string
+                 (setq string-start (point))
+                 (goto-char (scan-sexps (point) 1))
+                 (if (gyp-inside-dictionary-p)
+                     ;; Look for sections inside a dictionary
+                     (let ((section (gyp-section-name
+                                     (buffer-substring-no-properties
+                                      (+ 1 string-start)
+                                      (- (point) 1)))))
+                       (setq sections (cons section (cdr sections)))))
+                 ;; Stop after the string so it can be fontified.
+                 (setq target-point (point)))
+                ((looking-at-p "{")
+                 ;; Inside a dictionary. Increase nesting.
+                 (forward-char 1)
+                 (setq sections (cons 'unknown sections)))
+                ((looking-at-p "\\[")
+                 ;; Inside a list. Increase nesting
+                 (forward-char 1)
+                 (setq sections (cons 'list sections)))
+                ((not (eobp))
+                 ;; other
+                 (forward-char 1))))
+        (gyp-add-parse-history (point) sections)
+        (setq parsing (< (point) target-point))))
+    string-start))
+
+(defun gyp-section-at-point ()
+  "Transform the last parse state, which is a list of nested sections and return
+   the section symbol that should be used to determine font-lock information for
+   the string. Can return nil indicating the string should not have any attached
+   section."
+  (let ((sections (gyp-parse-sections)))
+    (cond
+     ((eq (car sections) 'conditions)
+      ;; conditions can occur in a variables section, but we still want to
+      ;; highlight it as a keyword.
+      nil)
+     ((and (eq (car sections) 'list)
+           (eq (cadr sections) 'list))
+      ;; conditions and sources can have items in [[ ]]
+      (caddr sections))
+     (t (cadr sections)))))
+
+(defun gyp-section-match (limit)
+  "Parse from (point) to LIMIT returning by means of match data what was
+   matched. The group of the match indicates what style font-lock should apply.
+   See also `gyp-add-font-lock-keywords'."
+  (gyp-invalidate-parse-states-after (point))
+  (let ((group nil)
+        (string-start t))
+    (while (and (< (point) limit)
+                (not group)
+                string-start)
+      (setq string-start (gyp-parse-to limit))
+      (if string-start
+          (setq group (cl-case (gyp-section-at-point)
+                        ('dependencies 1)
+                        ('variables 2)
+                        ('conditions 2)
+                        ('sources 3)
+                        ('defines 4)
+                        (nil nil)))))
+    (if group
+        (progn
+          ;; Set the match data to indicate to the font-lock mechanism the
+          ;; highlighting to be performed.
+          (set-match-data (append (list string-start (point))
+                                  (make-list (* (1- group) 2) nil)
+                                  (list (1+ string-start) (1- (point)))))
+          t))))
+
+;;; Please see http://code.google.com/p/gyp/wiki/GypLanguageSpecification for
+;;; canonical list of keywords.
+(defun gyp-add-font-lock-keywords ()
+  "Add gyp-mode keywords to font-lock mechanism."
+  ;; TODO(jknotten): Move all the keyword highlighting into gyp-section-match
+  ;; so that we can do the font-locking in a single font-lock pass.
+  (font-lock-add-keywords
+   nil
+   (list
+    ;; Top-level keywords
+    (list (concat "['\"]\$"
+              (regexp-opt (list "action" "action_name" "actions" "cflags"
+                                "cflags_cc" "conditions" "configurations"
+                                "copies" "defines" "dependencies" "destination"
+                                "direct_dependent_settings"
+                                "export_dependent_settings" "extension" "files"
+                                "include_dirs" "includes" "inputs" "ldflags" "libraries"
+                                "link_settings" "mac_bundle" "message"
+                                "msvs_external_rule" "outputs" "product_name"
+                                "process_outputs_as_sources" "rules" "rule_name"
+                                "sources" "suppress_wildcard"
+                                "target_conditions" "target_defaults"
+                                "target_defines" "target_name" "toolsets"
+                                "targets" "type" "variables" "xcode_settings"))
+              "[!/+=]?\$") 1 'font-lock-keyword-face t)
+    ;; Type of target
+    (list (concat "['\"]\$"
+              (regexp-opt (list "loadable_module" "static_library"
+                                "shared_library" "executable" "none"))
+              "\$") 1 'font-lock-type-face t)
+    (list "\$?:target\\|action\$_name['\"]\\s-*:\\s-*['\"]\$[^ '\"]*\$" 1
+          'font-lock-function-name-face t)
+    (list 'gyp-section-match
+          (list 1 'font-lock-function-name-face t t) ; dependencies
+          (list 2 'font-lock-variable-name-face t t) ; variables, conditions
+          (list 3 'font-lock-constant-face t t) ; sources
+          (list 4 'font-lock-preprocessor-face t t)) ; preprocessor
+    ;; Variable expansion
+    (list "<@?(\$[^\n )]+\$)" 1 'font-lock-variable-name-face t)
+    ;; Command expansion
+    (list "<!@?(\$[^\n )]+\$)" 1 'font-lock-variable-name-face t)
+    )))
+
+(provide 'gyp)
diff --git a/server/node_modules/node-gyp/gyp/tools/emacs/run-unit-tests.sh b/server/node_modules/node-gyp/gyp/tools/emacs/run-unit-tests.sh
new file mode 100755
index 0000000..6e62b9b
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/emacs/run-unit-tests.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+emacs --no-site-file --no-init-file --batch \
+      --load ert.el --load gyp.el --load gyp-tests.el \
+      -f ert-run-tests-batch-and-exit
diff --git a/server/node_modules/node-gyp/gyp/tools/emacs/testdata/media.gyp b/server/node_modules/node-gyp/gyp/tools/emacs/testdata/media.gyp
new file mode 100644
index 0000000..29300fe
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/emacs/testdata/media.gyp
@@ -0,0 +1,1105 @@
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+  'variables': {
+    'chromium_code': 1,
+    # Override to dynamically link the PulseAudio library.
+    'use_pulseaudio%': 0,
+    # Override to dynamically link the cras (ChromeOS audio) library.
+    'use_cras%': 0,
+  },
+  'targets': [
+    {
+      'target_name': 'media',
+      'type': '<(component)',
+      'dependencies': [
+        'yuv_convert',
+        '../base/base.gyp:base',
+        '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
+        '../build/temp_gyp/googleurl.gyp:googleurl',
+        '../crypto/crypto.gyp:crypto',
+        '../third_party/openmax/openmax.gyp:il',
+        '../ui/ui.gyp:ui',
+      ],
+      'defines': [
+        'MEDIA_IMPLEMENTATION',
+      ],
+      'include_dirs': [
+        '..',
+      ],
+      'sources': [
+        'audio/android/audio_manager_android.cc',
+        'audio/android/audio_manager_android.h',
+        'audio/android/audio_track_output_android.cc',
+        'audio/android/audio_track_output_android.h',
+        'audio/android/opensles_input.cc',
+        'audio/android/opensles_input.h',
+        'audio/android/opensles_output.cc',
+        'audio/android/opensles_output.h',
+        'audio/async_socket_io_handler.h',
+        'audio/async_socket_io_handler_posix.cc',
+        'audio/async_socket_io_handler_win.cc',
+        'audio/audio_buffers_state.cc',
+        'audio/audio_buffers_state.h',
+        'audio/audio_io.h',
+        'audio/audio_input_controller.cc',
+        'audio/audio_input_controller.h',
+        'audio/audio_input_stream_impl.cc',
+        'audio/audio_input_stream_impl.h',
+        'audio/audio_device_name.cc',
+        'audio/audio_device_name.h',
+        'audio/audio_manager.cc',
+        'audio/audio_manager.h',
+        'audio/audio_manager_base.cc',
+        'audio/audio_manager_base.h',
+        'audio/audio_output_controller.cc',
+        'audio/audio_output_controller.h',
+        'audio/audio_output_dispatcher.cc',
+        'audio/audio_output_dispatcher.h',
+        'audio/audio_output_dispatcher_impl.cc',
+        'audio/audio_output_dispatcher_impl.h',
+        'audio/audio_output_mixer.cc',
+        'audio/audio_output_mixer.h',
+        'audio/audio_output_proxy.cc',
+        'audio/audio_output_proxy.h',
+        'audio/audio_parameters.cc',
+        'audio/audio_parameters.h',
+        'audio/audio_util.cc',
+        'audio/audio_util.h',
+        'audio/cross_process_notification.cc',
+        'audio/cross_process_notification.h',
+        'audio/cross_process_notification_win.cc',
+        'audio/cross_process_notification_posix.cc',
+        'audio/fake_audio_input_stream.cc',
+        'audio/fake_audio_input_stream.h',
+        'audio/fake_audio_output_stream.cc',
+        'audio/fake_audio_output_stream.h',
+        'audio/linux/audio_manager_linux.cc',
+        'audio/linux/audio_manager_linux.h',
+        'audio/linux/alsa_input.cc',
+        'audio/linux/alsa_input.h',
+        'audio/linux/alsa_output.cc',
+        'audio/linux/alsa_output.h',
+        'audio/linux/alsa_util.cc',
+        'audio/linux/alsa_util.h',
+        'audio/linux/alsa_wrapper.cc',
+        'audio/linux/alsa_wrapper.h',
+        'audio/linux/cras_output.cc',
+        'audio/linux/cras_output.h',
+        'audio/openbsd/audio_manager_openbsd.cc',
+        'audio/openbsd/audio_manager_openbsd.h',
+        'audio/mac/audio_input_mac.cc',
+        'audio/mac/audio_input_mac.h',
+        'audio/mac/audio_low_latency_input_mac.cc',
+        'audio/mac/audio_low_latency_input_mac.h',
+        'audio/mac/audio_low_latency_output_mac.cc',
+        'audio/mac/audio_low_latency_output_mac.h',
+        'audio/mac/audio_manager_mac.cc',
+        'audio/mac/audio_manager_mac.h',
+        'audio/mac/audio_output_mac.cc',
+        'audio/mac/audio_output_mac.h',
+        'audio/null_audio_sink.cc',
+        'audio/null_audio_sink.h',
+        'audio/pulse/pulse_output.cc',
+        'audio/pulse/pulse_output.h',
+        'audio/sample_rates.cc',
+        'audio/sample_rates.h',
+        'audio/simple_sources.cc',
+        'audio/simple_sources.h',
+        'audio/win/audio_low_latency_input_win.cc',
+        'audio/win/audio_low_latency_input_win.h',
+        'audio/win/audio_low_latency_output_win.cc',
+        'audio/win/audio_low_latency_output_win.h',
+        'audio/win/audio_manager_win.cc',
+        'audio/win/audio_manager_win.h',
+        'audio/win/avrt_wrapper_win.cc',
+        'audio/win/avrt_wrapper_win.h',
+        'audio/win/device_enumeration_win.cc',
+        'audio/win/device_enumeration_win.h',
+        'audio/win/wavein_input_win.cc',
+        'audio/win/wavein_input_win.h',
+        'audio/win/waveout_output_win.cc',
+        'audio/win/waveout_output_win.h',
+        'base/android/media_jni_registrar.cc',
+        'base/android/media_jni_registrar.h',
+        'base/audio_decoder.cc',
+        'base/audio_decoder.h',
+        'base/audio_decoder_config.cc',
+        'base/audio_decoder_config.h',
+        'base/audio_renderer.h',
+        'base/audio_renderer_mixer.cc',
+        'base/audio_renderer_mixer.h',
+        'base/audio_renderer_mixer_input.cc',
+        'base/audio_renderer_mixer_input.h',
+        'base/bitstream_buffer.h',
+        'base/buffers.cc',
+        'base/buffers.h',
+        'base/byte_queue.cc',
+        'base/byte_queue.h',
+        'base/channel_layout.cc',
+        'base/channel_layout.h',
+        'base/clock.cc',
+        'base/clock.h',
+        'base/composite_filter.cc',
+        'base/composite_filter.h',
+        'base/data_buffer.cc',
+        'base/data_buffer.h',
+        'base/data_source.cc',
+        'base/data_source.h',
+        'base/decoder_buffer.cc',
+        'base/decoder_buffer.h',
+        'base/decrypt_config.cc',
+        'base/decrypt_config.h',
+        'base/decryptor.h',
+        'base/decryptor_client.h',
+        'base/demuxer.cc',
+        'base/demuxer.h',
+        'base/demuxer_stream.cc',
+        'base/demuxer_stream.h',
+        'base/djb2.cc',
+        'base/djb2.h',
+        'base/filter_collection.cc',
+        'base/filter_collection.h',
+        'base/filter_host.h',
+        'base/filters.cc',
+        'base/filters.h',
+        'base/h264_bitstream_converter.cc',
+        'base/h264_bitstream_converter.h',
+        'base/media.h',
+        'base/media_android.cc',
+        'base/media_export.h',
+        'base/media_log.cc',
+        'base/media_log.h',
+        'base/media_log_event.h',
+        'base/media_posix.cc',
+        'base/media_switches.cc',
+        'base/media_switches.h',
+        'base/media_win.cc',
+        'base/message_loop_factory.cc',
+        'base/message_loop_factory.h',
+        'base/pipeline.cc',
+        'base/pipeline.h',
+        'base/pipeline_status.cc',
+        'base/pipeline_status.h',
+        'base/ranges.cc',
+        'base/ranges.h',
+        'base/seekable_buffer.cc',
+        'base/seekable_buffer.h',
+        'base/state_matrix.cc',
+        'base/state_matrix.h',
+        'base/stream_parser.cc',
+        'base/stream_parser.h',
+        'base/stream_parser_buffer.cc',
+        'base/stream_parser_buffer.h',
+        'base/video_decoder.cc',
+        'base/video_decoder.h',
+        'base/video_decoder_config.cc',
+        'base/video_decoder_config.h',
+        'base/video_frame.cc',
+        'base/video_frame.h',
+        'base/video_renderer.h',
+        'base/video_util.cc',
+        'base/video_util.h',
+        'crypto/aes_decryptor.cc',
+        'crypto/aes_decryptor.h',
+        'ffmpeg/ffmpeg_common.cc',
+        'ffmpeg/ffmpeg_common.h',
+        'ffmpeg/file_protocol.cc',
+        'ffmpeg/file_protocol.h',
+        'filters/audio_file_reader.cc',
+        'filters/audio_file_reader.h',
+        'filters/audio_renderer_algorithm.cc',
+        'filters/audio_renderer_algorithm.h',
+        'filters/audio_renderer_impl.cc',
+        'filters/audio_renderer_impl.h',
+        'filters/bitstream_converter.cc',
+        'filters/bitstream_converter.h',
+        'filters/chunk_demuxer.cc',
+        'filters/chunk_demuxer.h',
+        'filters/chunk_demuxer_client.h',
+        'filters/dummy_demuxer.cc',
+        'filters/dummy_demuxer.h',
+        'filters/ffmpeg_audio_decoder.cc',
+        'filters/ffmpeg_audio_decoder.h',
+        'filters/ffmpeg_demuxer.cc',
+        'filters/ffmpeg_demuxer.h',
+        'filters/ffmpeg_h264_bitstream_converter.cc',
+        'filters/ffmpeg_h264_bitstream_converter.h',
+        'filters/ffmpeg_glue.cc',
+        'filters/ffmpeg_glue.h',
+        'filters/ffmpeg_video_decoder.cc',
+        'filters/ffmpeg_video_decoder.h',
+        'filters/file_data_source.cc',
+        'filters/file_data_source.h',
+        'filters/gpu_video_decoder.cc',
+        'filters/gpu_video_decoder.h',
+        'filters/in_memory_url_protocol.cc',
+        'filters/in_memory_url_protocol.h',
+        'filters/source_buffer_stream.cc',
+        'filters/source_buffer_stream.h',
+        'filters/video_frame_generator.cc',
+        'filters/video_frame_generator.h',
+        'filters/video_renderer_base.cc',
+        'filters/video_renderer_base.h',
+        'video/capture/fake_video_capture_device.cc',
+        'video/capture/fake_video_capture_device.h',
+        'video/capture/linux/video_capture_device_linux.cc',
+        'video/capture/linux/video_capture_device_linux.h',
+        'video/capture/mac/video_capture_device_mac.h',
+        'video/capture/mac/video_capture_device_mac.mm',
+        'video/capture/mac/video_capture_device_qtkit_mac.h',
+        'video/capture/mac/video_capture_device_qtkit_mac.mm',
+        'video/capture/video_capture.h',
+        'video/capture/video_capture_device.h',
+        'video/capture/video_capture_device_dummy.cc',
+        'video/capture/video_capture_device_dummy.h',
+        'video/capture/video_capture_proxy.cc',
+        'video/capture/video_capture_proxy.h',
+        'video/capture/video_capture_types.h',
+        'video/capture/win/filter_base_win.cc',
+        'video/capture/win/filter_base_win.h',
+        'video/capture/win/pin_base_win.cc',
+        'video/capture/win/pin_base_win.h',
+        'video/capture/win/sink_filter_observer_win.h',
+        'video/capture/win/sink_filter_win.cc',
+        'video/capture/win/sink_filter_win.h',
+        'video/capture/win/sink_input_pin_win.cc',
+        'video/capture/win/sink_input_pin_win.h',
+        'video/capture/win/video_capture_device_win.cc',
+        'video/capture/win/video_capture_device_win.h',
+        'video/picture.cc',
+        'video/picture.h',
+        'video/video_decode_accelerator.cc',
+        'video/video_decode_accelerator.h',
+        'webm/webm_constants.h',
+        'webm/webm_cluster_parser.cc',
+        'webm/webm_cluster_parser.h',
+        'webm/webm_content_encodings.cc',
+        'webm/webm_content_encodings.h',
+        'webm/webm_content_encodings_client.cc',
+        'webm/webm_content_encodings_client.h',
+        'webm/webm_info_parser.cc',
+        'webm/webm_info_parser.h',
+        'webm/webm_parser.cc',
+        'webm/webm_parser.h',
+        'webm/webm_stream_parser.cc',
+        'webm/webm_stream_parser.h',
+        'webm/webm_tracks_parser.cc',
+        'webm/webm_tracks_parser.h',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          '..',
+        ],
+      },
+      'conditions': [
+        # Android doesn't use ffmpeg, so make the dependency conditional
+        # and exclude the sources which depend on ffmpeg.
+        ['OS != "android"', {
+          'dependencies': [
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+        }],
+        ['OS == "android"', {
+          'sources!': [
+            'base/media_posix.cc',
+            'ffmpeg/ffmpeg_common.cc',
+            'ffmpeg/ffmpeg_common.h',
+            'ffmpeg/file_protocol.cc',
+            'ffmpeg/file_protocol.h',
+            'filters/audio_file_reader.cc',
+            'filters/audio_file_reader.h',
+            'filters/bitstream_converter.cc',
+            'filters/bitstream_converter.h',
+            'filters/chunk_demuxer.cc',
+            'filters/chunk_demuxer.h',
+            'filters/chunk_demuxer_client.h',
+            'filters/ffmpeg_audio_decoder.cc',
+            'filters/ffmpeg_audio_decoder.h',
+            'filters/ffmpeg_demuxer.cc',
+            'filters/ffmpeg_demuxer.h',
+            'filters/ffmpeg_h264_bitstream_converter.cc',
+            'filters/ffmpeg_h264_bitstream_converter.h',
+            'filters/ffmpeg_glue.cc',
+            'filters/ffmpeg_glue.h',
+            'filters/ffmpeg_video_decoder.cc',
+            'filters/ffmpeg_video_decoder.h',
+            'filters/gpu_video_decoder.cc',
+            'filters/gpu_video_decoder.h',
+            'webm/webm_cluster_parser.cc',
+            'webm/webm_cluster_parser.h',
+            'webm/webm_stream_parser.cc',
+            'webm/webm_stream_parser.h',
+          ],
+        }],
+        # The below 'android' condition were added temporarily and should be
+        # removed in downstream, because there is no Java environment setup in
+        # upstream yet.
+        ['OS == "android"', {
+          'sources!':[
+            'audio/android/audio_track_output_android.cc',
+          ],
+          'sources':[
+            'audio/android/audio_track_output_stub_android.cc',
+          ],
+          'link_settings': {
+            'libraries': [
+              '-lOpenSLES',
+            ],
+          },
+        }],
+        ['OS=="linux" or OS=="freebsd" or OS=="solaris"', {
+          'link_settings': {
+            'libraries': [
+              '-lasound',
+            ],
+          },
+        }],
+        ['OS=="openbsd"', {
+          'sources/': [ ['exclude', '/alsa_' ],
+                        ['exclude', '/audio_manager_linux' ] ],
+          'link_settings': {
+            'libraries': [
+            ],
+          },
+        }],
+        ['OS!="openbsd"', {
+          'sources!': [
+            'audio/openbsd/audio_manager_openbsd.cc',
+            'audio/openbsd/audio_manager_openbsd.h',
+          ],
+        }],
+        ['OS=="linux"', {
+          'variables': {
+            'conditions': [
+              ['sysroot!=""', {
+                'pkg-config': '../build/linux/pkg-config-wrapper "<(sysroot)" "<(target_arch)"',
+              }, {
+                'pkg-config': 'pkg-config'
+              }],
+            ],
+          },
+          'conditions': [
+            ['use_cras == 1', {
+              'cflags': [
+                '<!@(<(pkg-config) --cflags libcras)',
+              ],
+              'link_settings': {
+                'libraries': [
+                  '<!@(<(pkg-config) --libs libcras)',
+                ],
+              },
+              'defines': [
+                'USE_CRAS',
+              ],
+            }, {  # else: use_cras == 0
+              'sources!': [
+                'audio/linux/cras_output.cc',
+                'audio/linux/cras_output.h',
+              ],
+            }],
+          ],
+        }],
+        ['os_posix == 1', {
+          'conditions': [
+            ['use_pulseaudio == 1', {
+              'cflags': [
+                '<!@(pkg-config --cflags libpulse)',
+              ],
+              'link_settings': {
+                'libraries': [
+                  '<!@(pkg-config --libs-only-l libpulse)',
+                ],
+              },
+              'defines': [
+                'USE_PULSEAUDIO',
+              ],
+            }, {  # else: use_pulseaudio == 0
+              'sources!': [
+                'audio/pulse/pulse_output.cc',
+                'audio/pulse/pulse_output.h',
+              ],
+            }],
+          ],
+        }],
+        ['os_posix == 1 and OS != "android"', {
+          # Video capture isn't supported in Android yet.
+          'sources!': [
+            'video/capture/video_capture_device_dummy.cc',
+            'video/capture/video_capture_device_dummy.h',
+          ],
+        }],
+        ['OS=="mac"', {
+          'link_settings': {
+            'libraries': [
+              '$(SDKROOT)/System/Library/Frameworks/AudioUnit.framework',
+              '$(SDKROOT)/System/Library/Frameworks/AudioToolbox.framework',
+              '$(SDKROOT)/System/Library/Frameworks/CoreAudio.framework',
+              '$(SDKROOT)/System/Library/Frameworks/CoreVideo.framework',
+              '$(SDKROOT)/System/Library/Frameworks/QTKit.framework',
+            ],
+          },
+        }],
+        ['OS=="win"', {
+          'sources!': [
+            'audio/pulse/pulse_output.cc',
+            'audio/pulse/pulse_output.h',
+            'video/capture/video_capture_device_dummy.cc',
+            'video/capture/video_capture_device_dummy.h',
+          ],
+        }],
+        ['proprietary_codecs==1 or branding=="Chrome"', {
+          'sources': [
+            'mp4/avc.cc',
+            'mp4/avc.h',
+            'mp4/box_definitions.cc',
+            'mp4/box_definitions.h',
+            'mp4/box_reader.cc',
+            'mp4/box_reader.h',
+            'mp4/cenc.cc',
+            'mp4/cenc.h',
+            'mp4/mp4_stream_parser.cc',
+            'mp4/mp4_stream_parser.h',
+            'mp4/offset_byte_queue.cc',
+            'mp4/offset_byte_queue.h',
+            'mp4/track_run_iterator.cc',
+            'mp4/track_run_iterator.h',
+          ],
+        }],
+      ],
+    },
+    {
+      'target_name': 'yuv_convert',
+      'type': 'static_library',
+      'include_dirs': [
+        '..',
+      ],
+      'conditions': [
+        ['order_profiling != 0', {
+          'target_conditions' : [
+            ['_toolset=="target"', {
+              'cflags!': [ '-finstrument-functions' ],
+            }],
+          ],
+        }],
+        [ 'target_arch == "ia32" or target_arch == "x64"', {
+          'dependencies': [
+            'yuv_convert_simd_x86',
+          ],
+        }],
+        [ 'target_arch == "arm"', {
+          'dependencies': [
+            'yuv_convert_simd_arm',
+          ],
+        }],
+      ],
+      'sources': [
+        'base/yuv_convert.cc',
+        'base/yuv_convert.h',
+      ],
+    },
+    {
+      'target_name': 'yuv_convert_simd_x86',
+      'type': 'static_library',
+      'include_dirs': [
+        '..',
+      ],
+      'sources': [
+        'base/simd/convert_rgb_to_yuv_c.cc',
+        'base/simd/convert_rgb_to_yuv_sse2.cc',
+        'base/simd/convert_rgb_to_yuv_ssse3.asm',
+        'base/simd/convert_rgb_to_yuv_ssse3.cc',
+        'base/simd/convert_rgb_to_yuv_ssse3.inc',
+        'base/simd/convert_yuv_to_rgb_c.cc',
+        'base/simd/convert_yuv_to_rgb_x86.cc',
+        'base/simd/convert_yuv_to_rgb_mmx.asm',
+        'base/simd/convert_yuv_to_rgb_mmx.inc',
+        'base/simd/convert_yuv_to_rgb_sse.asm',
+        'base/simd/filter_yuv.h',
+        'base/simd/filter_yuv_c.cc',
+        'base/simd/filter_yuv_mmx.cc',
+        'base/simd/filter_yuv_sse2.cc',
+        'base/simd/linear_scale_yuv_to_rgb_mmx.asm',
+        'base/simd/linear_scale_yuv_to_rgb_mmx.inc',
+        'base/simd/linear_scale_yuv_to_rgb_sse.asm',
+        'base/simd/scale_yuv_to_rgb_mmx.asm',
+        'base/simd/scale_yuv_to_rgb_mmx.inc',
+        'base/simd/scale_yuv_to_rgb_sse.asm',
+        'base/simd/yuv_to_rgb_table.cc',
+        'base/simd/yuv_to_rgb_table.h',
+      ],
+      'conditions': [
+        ['order_profiling != 0', {
+          'target_conditions' : [
+            ['_toolset=="target"', {
+              'cflags!': [ '-finstrument-functions' ],
+            }],
+          ],
+        }],
+        [ 'target_arch == "x64"', {
+          # Source files optimized for X64 systems.
+          'sources': [
+            'base/simd/linear_scale_yuv_to_rgb_mmx_x64.asm',
+            'base/simd/scale_yuv_to_rgb_sse2_x64.asm',
+          ],
+        }],
+        [ 'os_posix == 1 and OS != "mac" and OS != "android"', {
+          'cflags': [
+            '-msse2',
+          ],
+        }],
+        [ 'OS == "mac"', {
+          'configurations': {
+            'Debug': {
+              'xcode_settings': {
+                # gcc on the mac builds horribly unoptimized sse code in debug
+                # mode. Since this is rarely going to be debugged, run with full
+                # optimizations in Debug as well as Release.
+                'GCC_OPTIMIZATION_LEVEL': '3',  # -O3
+               },
+             },
+          },
+        }],
+        [ 'OS=="win"', {
+          'variables': {
+            'yasm_flags': [
+              '-DWIN32',
+              '-DMSVC',
+              '-DCHROMIUM',
+              '-Isimd',
+            ],
+          },
+        }],
+        [ 'OS=="mac"', {
+          'variables': {
+            'yasm_flags': [
+              '-DPREFIX',
+              '-DMACHO',
+              '-DCHROMIUM',
+              '-Isimd',
+            ],
+          },
+        }],
+        [ 'os_posix==1 and OS!="mac"', {
+          'variables': {
+            'conditions': [
+              [ 'target_arch=="ia32"', {
+                'yasm_flags': [
+                  '-DX86_32',
+                  '-DELF',
+                  '-DCHROMIUM',
+                  '-Isimd',
+                ],
+              }, {
+                'yasm_flags': [
+                  '-DARCH_X86_64',
+                  '-DELF',
+                  '-DPIC',
+                  '-DCHROMIUM',
+                  '-Isimd',
+                ],
+              }],
+            ],
+          },
+        }],
+      ],
+      'variables': {
+        'yasm_output_path': '<(SHARED_INTERMEDIATE_DIR)/media',
+      },
+      'msvs_2010_disable_uldi_when_referenced': 1,
+      'includes': [
+        '../third_party/yasm/yasm_compile.gypi',
+      ],
+    },
+    {
+      'target_name': 'yuv_convert_simd_arm',
+      'type': 'static_library',
+      'include_dirs': [
+        '..',
+      ],
+      'sources': [
+        'base/simd/convert_rgb_to_yuv_c.cc',
+        'base/simd/convert_rgb_to_yuv.h',
+        'base/simd/convert_yuv_to_rgb_c.cc',
+        'base/simd/convert_yuv_to_rgb.h',
+        'base/simd/filter_yuv.h',
+        'base/simd/filter_yuv_c.cc',
+        'base/simd/yuv_to_rgb_table.cc',
+        'base/simd/yuv_to_rgb_table.h',
+      ],
+    },
+    {
+      'target_name': 'media_unittests',
+      'type': 'executable',
+      'dependencies': [
+        'media',
+        'media_test_support',
+        'yuv_convert',
+        '../base/base.gyp:base',
+        '../base/base.gyp:base_i18n',
+        '../base/base.gyp:test_support_base',
+        '../testing/gmock.gyp:gmock',
+        '../testing/gtest.gyp:gtest',
+        '../ui/ui.gyp:ui',
+      ],
+      'sources': [
+        'audio/async_socket_io_handler_unittest.cc',
+        'audio/audio_input_controller_unittest.cc',
+        'audio/audio_input_device_unittest.cc',
+        'audio/audio_input_unittest.cc',
+        'audio/audio_input_volume_unittest.cc',
+        'audio/audio_low_latency_input_output_unittest.cc',
+        'audio/audio_output_controller_unittest.cc',
+        'audio/audio_output_proxy_unittest.cc',
+        'audio/audio_parameters_unittest.cc',
+        'audio/audio_util_unittest.cc',
+        'audio/cross_process_notification_unittest.cc',
+        'audio/linux/alsa_output_unittest.cc',
+        'audio/mac/audio_low_latency_input_mac_unittest.cc',
+        'audio/mac/audio_output_mac_unittest.cc',
+        'audio/simple_sources_unittest.cc',
+        'audio/win/audio_low_latency_input_win_unittest.cc',
+        'audio/win/audio_low_latency_output_win_unittest.cc',
+        'audio/win/audio_output_win_unittest.cc',
+        'base/audio_renderer_mixer_unittest.cc',
+        'base/audio_renderer_mixer_input_unittest.cc',
+        'base/buffers_unittest.cc',
+        'base/clock_unittest.cc',
+        'base/composite_filter_unittest.cc',
+        'base/data_buffer_unittest.cc',
+        'base/decoder_buffer_unittest.cc',
+        'base/djb2_unittest.cc',
+        'base/fake_audio_render_callback.cc',
+        'base/fake_audio_render_callback.h',
+        'base/filter_collection_unittest.cc',
+        'base/h264_bitstream_converter_unittest.cc',
+        'base/pipeline_unittest.cc',
+        'base/ranges_unittest.cc',
+        'base/run_all_unittests.cc',
+        'base/seekable_buffer_unittest.cc',
+        'base/state_matrix_unittest.cc',
+        'base/test_data_util.cc',
+        'base/test_data_util.h',
+        'base/video_frame_unittest.cc',
+        'base/video_util_unittest.cc',
+        'base/yuv_convert_unittest.cc',
+        'crypto/aes_decryptor_unittest.cc',
+        'ffmpeg/ffmpeg_common_unittest.cc',
+        'filters/audio_renderer_algorithm_unittest.cc',
+        'filters/audio_renderer_impl_unittest.cc',
+        'filters/bitstream_converter_unittest.cc',
+        'filters/chunk_demuxer_unittest.cc',
+        'filters/ffmpeg_audio_decoder_unittest.cc',
+        'filters/ffmpeg_decoder_unittest.h',
+        'filters/ffmpeg_demuxer_unittest.cc',
+        'filters/ffmpeg_glue_unittest.cc',
+        'filters/ffmpeg_h264_bitstream_converter_unittest.cc',
+        'filters/ffmpeg_video_decoder_unittest.cc',
+        'filters/file_data_source_unittest.cc',
+        'filters/pipeline_integration_test.cc',
+        'filters/pipeline_integration_test_base.cc',
+        'filters/source_buffer_stream_unittest.cc',
+        'filters/video_renderer_base_unittest.cc',
+        'video/capture/video_capture_device_unittest.cc',
+        'webm/cluster_builder.cc',
+        'webm/cluster_builder.h',
+        'webm/webm_cluster_parser_unittest.cc',
+        'webm/webm_content_encodings_client_unittest.cc',
+        'webm/webm_parser_unittest.cc',
+      ],
+      'conditions': [
+        ['os_posix==1 and OS!="mac"', {
+          'conditions': [
+            ['linux_use_tcmalloc==1', {
+              'dependencies': [
+                '../base/allocator/allocator.gyp:allocator',
+              ],
+            }],
+          ],
+        }],
+        ['OS != "android"', {
+          'dependencies': [
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+        }],
+        ['OS == "android"', {
+          'sources!': [
+            'audio/audio_input_volume_unittest.cc',
+            'base/test_data_util.cc',
+            'base/test_data_util.h',
+            'ffmpeg/ffmpeg_common_unittest.cc',
+            'filters/ffmpeg_audio_decoder_unittest.cc',
+            'filters/bitstream_converter_unittest.cc',
+            'filters/chunk_demuxer_unittest.cc',
+            'filters/ffmpeg_demuxer_unittest.cc',
+            'filters/ffmpeg_glue_unittest.cc',
+            'filters/ffmpeg_h264_bitstream_converter_unittest.cc',
+            'filters/ffmpeg_video_decoder_unittest.cc',
+            'filters/pipeline_integration_test.cc',
+            'filters/pipeline_integration_test_base.cc',
+            'mp4/mp4_stream_parser_unittest.cc',
+            'webm/webm_cluster_parser_unittest.cc',
+          ],
+        }],
+        ['OS == "linux"', {
+          'conditions': [
+            ['use_cras == 1', {
+              'sources': [
+                'audio/linux/cras_output_unittest.cc',
+              ],
+              'defines': [
+                'USE_CRAS',
+              ],
+            }],
+          ],
+        }],
+        [ 'target_arch=="ia32" or target_arch=="x64"', {
+          'sources': [
+            'base/simd/convert_rgb_to_yuv_unittest.cc',
+          ],
+        }],
+        ['proprietary_codecs==1 or branding=="Chrome"', {
+          'sources': [
+            'mp4/avc_unittest.cc',
+            'mp4/box_reader_unittest.cc',
+            'mp4/mp4_stream_parser_unittest.cc',
+            'mp4/offset_byte_queue_unittest.cc',
+          ],
+        }],
+      ],
+    },
+    {
+      'target_name': 'media_test_support',
+      'type': 'static_library',
+      'dependencies': [
+        'media',
+        '../base/base.gyp:base',
+        '../testing/gmock.gyp:gmock',
+        '../testing/gtest.gyp:gtest',
+      ],
+      'sources': [
+        'audio/test_audio_input_controller_factory.cc',
+        'audio/test_audio_input_controller_factory.h',
+        'base/mock_callback.cc',
+        'base/mock_callback.h',
+        'base/mock_data_source_host.cc',
+        'base/mock_data_source_host.h',
+        'base/mock_demuxer_host.cc',
+        'base/mock_demuxer_host.h',
+        'base/mock_filter_host.cc',
+        'base/mock_filter_host.h',
+        'base/mock_filters.cc',
+        'base/mock_filters.h',
+      ],
+    },
+    {
+      'target_name': 'scaler_bench',
+      'type': 'executable',
+      'dependencies': [
+        'media',
+        'yuv_convert',
+        '../base/base.gyp:base',
+        '../skia/skia.gyp:skia',
+      ],
+      'sources': [
+        'tools/scaler_bench/scaler_bench.cc',
+      ],
+    },
+    {
+      'target_name': 'qt_faststart',
+      'type': 'executable',
+      'sources': [
+        'tools/qt_faststart/qt_faststart.c'
+      ],
+    },
+    {
+      'target_name': 'seek_tester',
+      'type': 'executable',
+      'dependencies': [
+        'media',
+        '../base/base.gyp:base',
+      ],
+      'sources': [
+        'tools/seek_tester/seek_tester.cc',
+      ],
+    },
+  ],
+  'conditions': [
+    ['OS=="win"', {
+      'targets': [
+        {
+          'target_name': 'player_wtl',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'yuv_convert',
+            '../base/base.gyp:base',
+            '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
+            '../ui/ui.gyp:ui',
+          ],
+          'include_dirs': [
+            '<(DEPTH)/third_party/wtl/include',
+          ],
+          'sources': [
+            'tools/player_wtl/list.h',
+            'tools/player_wtl/mainfrm.h',
+            'tools/player_wtl/movie.cc',
+            'tools/player_wtl/movie.h',
+            'tools/player_wtl/player_wtl.cc',
+            'tools/player_wtl/player_wtl.rc',
+            'tools/player_wtl/props.h',
+            'tools/player_wtl/seek.h',
+            'tools/player_wtl/resource.h',
+            'tools/player_wtl/view.h',
+          ],
+          'msvs_settings': {
+            'VCLinkerTool': {
+              'SubSystem': '2',         # Set /SUBSYSTEM:WINDOWS
+            },
+          },
+          'defines': [
+            '_CRT_SECURE_NO_WARNINGS=1',
+          ],
+        },
+      ],
+    }],
+    ['OS == "win" or toolkit_uses_gtk == 1', {
+      'targets': [
+        {
+          'target_name': 'shader_bench',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'yuv_convert',
+            '../base/base.gyp:base',
+            '../ui/gl/gl.gyp:gl',
+          ],
+          'sources': [
+            'tools/shader_bench/shader_bench.cc',
+            'tools/shader_bench/cpu_color_painter.cc',
+            'tools/shader_bench/cpu_color_painter.h',
+            'tools/shader_bench/gpu_color_painter.cc',
+            'tools/shader_bench/gpu_color_painter.h',
+            'tools/shader_bench/gpu_painter.cc',
+            'tools/shader_bench/gpu_painter.h',
+            'tools/shader_bench/painter.cc',
+            'tools/shader_bench/painter.h',
+            'tools/shader_bench/window.cc',
+            'tools/shader_bench/window.h',
+          ],
+          'conditions': [
+            ['toolkit_uses_gtk == 1', {
+              'dependencies': [
+                '../build/linux/system.gyp:gtk',
+              ],
+              'sources': [
+                'tools/shader_bench/window_linux.cc',
+              ],
+            }],
+            ['OS=="win"', {
+              'dependencies': [
+                '../third_party/angle/src/build_angle.gyp:libEGL',
+                '../third_party/angle/src/build_angle.gyp:libGLESv2',
+              ],
+              'sources': [
+                'tools/shader_bench/window_win.cc',
+              ],
+            }],
+          ],
+        },
+      ],
+    }],
+    ['OS == "linux" and target_arch != "arm"', {
+      'targets': [
+        {
+          'target_name': 'tile_render_bench',
+          'type': 'executable',
+          'dependencies': [
+            '../base/base.gyp:base',
+            '../ui/gl/gl.gyp:gl',
+          ],
+          'libraries': [
+            '-lGL',
+            '-ldl',
+          ],
+          'sources': [
+            'tools/tile_render_bench/tile_render_bench.cc',
+          ],
+        },
+      ],
+    }],
+    ['os_posix == 1 and OS != "mac" and OS != "android"', {
+      'targets': [
+        {
+          'target_name': 'player_x11',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'yuv_convert',
+            '../base/base.gyp:base',
+            '../ui/gl/gl.gyp:gl',
+          ],
+          'link_settings': {
+            'libraries': [
+              '-ldl',
+              '-lX11',
+              '-lXrender',
+              '-lXext',
+            ],
+          },
+          'sources': [
+            'tools/player_x11/data_source_logger.cc',
+            'tools/player_x11/data_source_logger.h',
+            'tools/player_x11/gl_video_renderer.cc',
+            'tools/player_x11/gl_video_renderer.h',
+            'tools/player_x11/player_x11.cc',
+            'tools/player_x11/x11_video_renderer.cc',
+            'tools/player_x11/x11_video_renderer.h',
+          ],
+        },
+      ],
+    }],
+    ['OS == "android"', {
+      'targets': [
+        {
+          'target_name': 'player_android',
+          'type': 'static_library',
+          'sources': [
+            'base/android/media_player_bridge.cc',
+            'base/android/media_player_bridge.h',
+          ],
+          'dependencies': [
+            '../base/base.gyp:base',
+          ],
+          'include_dirs': [
+            '<(SHARED_INTERMEDIATE_DIR)/media',
+          ],
+          'actions': [
+            {
+              'action_name': 'generate-jni-headers',
+              'inputs': [
+                '../base/android/jni_generator/jni_generator.py',
+                'base/android/java/src/org/chromium/media/MediaPlayerListener.java',
+              ],
+              'outputs': [
+                '<(SHARED_INTERMEDIATE_DIR)/media/jni/media_player_listener_jni.h',
+              ],
+              'action': [
+                'python',
+                '<(DEPTH)/base/android/jni_generator/jni_generator.py',
+                '-o',
+                '<@(_inputs)',
+                '<@(_outputs)',
+              ],
+            },
+          ],
+        },
+        {
+          'target_name': 'media_java',
+          'type': 'none',
+          'dependencies': [ '../base/base.gyp:base_java' ],
+          'variables': {
+            'package_name': 'media',
+            'java_in_dir': 'base/android/java',
+          },
+          'includes': [ '../build/java.gypi' ],
+        },
+
+      ],
+    }, { # OS != "android"'
+      # Android does not use ffmpeg, so disable the targets which require it.
+      'targets': [
+        {
+          'target_name': 'ffmpeg_unittests',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'media_test_support',
+            '../base/base.gyp:base',
+            '../base/base.gyp:base_i18n',
+            '../base/base.gyp:test_support_base',
+            '../base/base.gyp:test_support_perf',
+            '../testing/gtest.gyp:gtest',
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+          'sources': [
+            'ffmpeg/ffmpeg_unittest.cc',
+          ],
+          'conditions': [
+            ['toolkit_uses_gtk == 1', {
+              'dependencies': [
+                # Needed for the following #include chain:
+                #   base/run_all_unittests.cc
+                #   ../base/test_suite.h
+                #   gtk/gtk.h
+                '../build/linux/system.gyp:gtk',
+              ],
+              'conditions': [
+                ['linux_use_tcmalloc==1', {
+                  'dependencies': [
+                    '../base/allocator/allocator.gyp:allocator',
+                  ],
+                }],
+              ],
+            }],
+          ],
+        },
+        {
+          'target_name': 'ffmpeg_regression_tests',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'media_test_support',
+            '../base/base.gyp:test_support_base',
+            '../testing/gmock.gyp:gmock',
+            '../testing/gtest.gyp:gtest',
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+          'sources': [
+            'base/test_data_util.cc',
+            'base/run_all_unittests.cc',
+            'ffmpeg/ffmpeg_regression_tests.cc',
+            'filters/pipeline_integration_test_base.cc',
+          ],
+          'conditions': [
+            ['os_posix==1 and OS!="mac"', {
+              'conditions': [
+                ['linux_use_tcmalloc==1', {
+                  'dependencies': [
+                    '../base/allocator/allocator.gyp:allocator',
+                  ],
+                }],
+              ],
+            }],
+          ],
+        },
+        {
+          'target_name': 'ffmpeg_tests',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            '../base/base.gyp:base',
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+          'sources': [
+            'test/ffmpeg_tests/ffmpeg_tests.cc',
+          ],
+        },
+        {
+          'target_name': 'media_bench',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            '../base/base.gyp:base',
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+          'sources': [
+            'tools/media_bench/media_bench.cc',
+          ],
+        },
+      ],
+    }]
+  ],
+}
diff --git a/server/node_modules/node-gyp/gyp/tools/emacs/testdata/media.gyp.fontified b/server/node_modules/node-gyp/gyp/tools/emacs/testdata/media.gyp.fontified
new file mode 100644
index 0000000..962b7b2
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/emacs/testdata/media.gyp.fontified
@@ -0,0 +1,1107 @@
+
+#("# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+  'variables': {
+    'chromium_code': 1,
+    # Override to dynamically link the PulseAudio library.
+    'use_pulseaudio%': 0,
+    # Override to dynamically link the cras (ChromeOS audio) library.
+    'use_cras%': 0,
+  },
+  'targets': [
+    {
+      'target_name': 'media',
+      'type': '<(component)',
+      'dependencies': [
+        'yuv_convert',
+        '../base/base.gyp:base',
+        '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
+        '../build/temp_gyp/googleurl.gyp:googleurl',
+        '../crypto/crypto.gyp:crypto',
+        '../third_party/openmax/openmax.gyp:il',
+        '../ui/ui.gyp:ui',
+      ],
+      'defines': [
+        'MEDIA_IMPLEMENTATION',
+      ],
+      'include_dirs': [
+        '..',
+      ],
+      'sources': [
+        'audio/android/audio_manager_android.cc',
+        'audio/android/audio_manager_android.h',
+        'audio/android/audio_track_output_android.cc',
+        'audio/android/audio_track_output_android.h',
+        'audio/android/opensles_input.cc',
+        'audio/android/opensles_input.h',
+        'audio/android/opensles_output.cc',
+        'audio/android/opensles_output.h',
+        'audio/async_socket_io_handler.h',
+        'audio/async_socket_io_handler_posix.cc',
+        'audio/async_socket_io_handler_win.cc',
+        'audio/audio_buffers_state.cc',
+        'audio/audio_buffers_state.h',
+        'audio/audio_io.h',
+        'audio/audio_input_controller.cc',
+        'audio/audio_input_controller.h',
+        'audio/audio_input_stream_impl.cc',
+        'audio/audio_input_stream_impl.h',
+        'audio/audio_device_name.cc',
+        'audio/audio_device_name.h',
+        'audio/audio_manager.cc',
+        'audio/audio_manager.h',
+        'audio/audio_manager_base.cc',
+        'audio/audio_manager_base.h',
+        'audio/audio_output_controller.cc',
+        'audio/audio_output_controller.h',
+        'audio/audio_output_dispatcher.cc',
+        'audio/audio_output_dispatcher.h',
+        'audio/audio_output_dispatcher_impl.cc',
+        'audio/audio_output_dispatcher_impl.h',
+        'audio/audio_output_mixer.cc',
+        'audio/audio_output_mixer.h',
+        'audio/audio_output_proxy.cc',
+        'audio/audio_output_proxy.h',
+        'audio/audio_parameters.cc',
+        'audio/audio_parameters.h',
+        'audio/audio_util.cc',
+        'audio/audio_util.h',
+        'audio/cross_process_notification.cc',
+        'audio/cross_process_notification.h',
+        'audio/cross_process_notification_win.cc',
+        'audio/cross_process_notification_posix.cc',
+        'audio/fake_audio_input_stream.cc',
+        'audio/fake_audio_input_stream.h',
+        'audio/fake_audio_output_stream.cc',
+        'audio/fake_audio_output_stream.h',
+        'audio/linux/audio_manager_linux.cc',
+        'audio/linux/audio_manager_linux.h',
+        'audio/linux/alsa_input.cc',
+        'audio/linux/alsa_input.h',
+        'audio/linux/alsa_output.cc',
+        'audio/linux/alsa_output.h',
+        'audio/linux/alsa_util.cc',
+        'audio/linux/alsa_util.h',
+        'audio/linux/alsa_wrapper.cc',
+        'audio/linux/alsa_wrapper.h',
+        'audio/linux/cras_output.cc',
+        'audio/linux/cras_output.h',
+        'audio/openbsd/audio_manager_openbsd.cc',
+        'audio/openbsd/audio_manager_openbsd.h',
+        'audio/mac/audio_input_mac.cc',
+        'audio/mac/audio_input_mac.h',
+        'audio/mac/audio_low_latency_input_mac.cc',
+        'audio/mac/audio_low_latency_input_mac.h',
+        'audio/mac/audio_low_latency_output_mac.cc',
+        'audio/mac/audio_low_latency_output_mac.h',
+        'audio/mac/audio_manager_mac.cc',
+        'audio/mac/audio_manager_mac.h',
+        'audio/mac/audio_output_mac.cc',
+        'audio/mac/audio_output_mac.h',
+        'audio/null_audio_sink.cc',
+        'audio/null_audio_sink.h',
+        'audio/pulse/pulse_output.cc',
+        'audio/pulse/pulse_output.h',
+        'audio/sample_rates.cc',
+        'audio/sample_rates.h',
+        'audio/simple_sources.cc',
+        'audio/simple_sources.h',
+        'audio/win/audio_low_latency_input_win.cc',
+        'audio/win/audio_low_latency_input_win.h',
+        'audio/win/audio_low_latency_output_win.cc',
+        'audio/win/audio_low_latency_output_win.h',
+        'audio/win/audio_manager_win.cc',
+        'audio/win/audio_manager_win.h',
+        'audio/win/avrt_wrapper_win.cc',
+        'audio/win/avrt_wrapper_win.h',
+        'audio/win/device_enumeration_win.cc',
+        'audio/win/device_enumeration_win.h',
+        'audio/win/wavein_input_win.cc',
+        'audio/win/wavein_input_win.h',
+        'audio/win/waveout_output_win.cc',
+        'audio/win/waveout_output_win.h',
+        'base/android/media_jni_registrar.cc',
+        'base/android/media_jni_registrar.h',
+        'base/audio_decoder.cc',
+        'base/audio_decoder.h',
+        'base/audio_decoder_config.cc',
+        'base/audio_decoder_config.h',
+        'base/audio_renderer.h',
+        'base/audio_renderer_mixer.cc',
+        'base/audio_renderer_mixer.h',
+        'base/audio_renderer_mixer_input.cc',
+        'base/audio_renderer_mixer_input.h',
+        'base/bitstream_buffer.h',
+        'base/buffers.cc',
+        'base/buffers.h',
+        'base/byte_queue.cc',
+        'base/byte_queue.h',
+        'base/channel_layout.cc',
+        'base/channel_layout.h',
+        'base/clock.cc',
+        'base/clock.h',
+        'base/composite_filter.cc',
+        'base/composite_filter.h',
+        'base/data_buffer.cc',
+        'base/data_buffer.h',
+        'base/data_source.cc',
+        'base/data_source.h',
+        'base/decoder_buffer.cc',
+        'base/decoder_buffer.h',
+        'base/decrypt_config.cc',
+        'base/decrypt_config.h',
+        'base/decryptor.h',
+        'base/decryptor_client.h',
+        'base/demuxer.cc',
+        'base/demuxer.h',
+        'base/demuxer_stream.cc',
+        'base/demuxer_stream.h',
+        'base/djb2.cc',
+        'base/djb2.h',
+        'base/filter_collection.cc',
+        'base/filter_collection.h',
+        'base/filter_host.h',
+        'base/filters.cc',
+        'base/filters.h',
+        'base/h264_bitstream_converter.cc',
+        'base/h264_bitstream_converter.h',
+        'base/media.h',
+        'base/media_android.cc',
+        'base/media_export.h',
+        'base/media_log.cc',
+        'base/media_log.h',
+        'base/media_log_event.h',
+        'base/media_posix.cc',
+        'base/media_switches.cc',
+        'base/media_switches.h',
+        'base/media_win.cc',
+        'base/message_loop_factory.cc',
+        'base/message_loop_factory.h',
+        'base/pipeline.cc',
+        'base/pipeline.h',
+        'base/pipeline_status.cc',
+        'base/pipeline_status.h',
+        'base/ranges.cc',
+        'base/ranges.h',
+        'base/seekable_buffer.cc',
+        'base/seekable_buffer.h',
+        'base/state_matrix.cc',
+        'base/state_matrix.h',
+        'base/stream_parser.cc',
+        'base/stream_parser.h',
+        'base/stream_parser_buffer.cc',
+        'base/stream_parser_buffer.h',
+        'base/video_decoder.cc',
+        'base/video_decoder.h',
+        'base/video_decoder_config.cc',
+        'base/video_decoder_config.h',
+        'base/video_frame.cc',
+        'base/video_frame.h',
+        'base/video_renderer.h',
+        'base/video_util.cc',
+        'base/video_util.h',
+        'crypto/aes_decryptor.cc',
+        'crypto/aes_decryptor.h',
+        'ffmpeg/ffmpeg_common.cc',
+        'ffmpeg/ffmpeg_common.h',
+        'ffmpeg/file_protocol.cc',
+        'ffmpeg/file_protocol.h',
+        'filters/audio_file_reader.cc',
+        'filters/audio_file_reader.h',
+        'filters/audio_renderer_algorithm.cc',
+        'filters/audio_renderer_algorithm.h',
+        'filters/audio_renderer_impl.cc',
+        'filters/audio_renderer_impl.h',
+        'filters/bitstream_converter.cc',
+        'filters/bitstream_converter.h',
+        'filters/chunk_demuxer.cc',
+        'filters/chunk_demuxer.h',
+        'filters/chunk_demuxer_client.h',
+        'filters/dummy_demuxer.cc',
+        'filters/dummy_demuxer.h',
+        'filters/ffmpeg_audio_decoder.cc',
+        'filters/ffmpeg_audio_decoder.h',
+        'filters/ffmpeg_demuxer.cc',
+        'filters/ffmpeg_demuxer.h',
+        'filters/ffmpeg_h264_bitstream_converter.cc',
+        'filters/ffmpeg_h264_bitstream_converter.h',
+        'filters/ffmpeg_glue.cc',
+        'filters/ffmpeg_glue.h',
+        'filters/ffmpeg_video_decoder.cc',
+        'filters/ffmpeg_video_decoder.h',
+        'filters/file_data_source.cc',
+        'filters/file_data_source.h',
+        'filters/gpu_video_decoder.cc',
+        'filters/gpu_video_decoder.h',
+        'filters/in_memory_url_protocol.cc',
+        'filters/in_memory_url_protocol.h',
+        'filters/source_buffer_stream.cc',
+        'filters/source_buffer_stream.h',
+        'filters/video_frame_generator.cc',
+        'filters/video_frame_generator.h',
+        'filters/video_renderer_base.cc',
+        'filters/video_renderer_base.h',
+        'video/capture/fake_video_capture_device.cc',
+        'video/capture/fake_video_capture_device.h',
+        'video/capture/linux/video_capture_device_linux.cc',
+        'video/capture/linux/video_capture_device_linux.h',
+        'video/capture/mac/video_capture_device_mac.h',
+        'video/capture/mac/video_capture_device_mac.mm',
+        'video/capture/mac/video_capture_device_qtkit_mac.h',
+        'video/capture/mac/video_capture_device_qtkit_mac.mm',
+        'video/capture/video_capture.h',
+        'video/capture/video_capture_device.h',
+        'video/capture/video_capture_device_dummy.cc',
+        'video/capture/video_capture_device_dummy.h',
+        'video/capture/video_capture_proxy.cc',
+        'video/capture/video_capture_proxy.h',
+        'video/capture/video_capture_types.h',
+        'video/capture/win/filter_base_win.cc',
+        'video/capture/win/filter_base_win.h',
+        'video/capture/win/pin_base_win.cc',
+        'video/capture/win/pin_base_win.h',
+        'video/capture/win/sink_filter_observer_win.h',
+        'video/capture/win/sink_filter_win.cc',
+        'video/capture/win/sink_filter_win.h',
+        'video/capture/win/sink_input_pin_win.cc',
+        'video/capture/win/sink_input_pin_win.h',
+        'video/capture/win/video_capture_device_win.cc',
+        'video/capture/win/video_capture_device_win.h',
+        'video/picture.cc',
+        'video/picture.h',
+        'video/video_decode_accelerator.cc',
+        'video/video_decode_accelerator.h',
+        'webm/webm_constants.h',
+        'webm/webm_cluster_parser.cc',
+        'webm/webm_cluster_parser.h',
+        'webm/webm_content_encodings.cc',
+        'webm/webm_content_encodings.h',
+        'webm/webm_content_encodings_client.cc',
+        'webm/webm_content_encodings_client.h',
+        'webm/webm_info_parser.cc',
+        'webm/webm_info_parser.h',
+        'webm/webm_parser.cc',
+        'webm/webm_parser.h',
+        'webm/webm_stream_parser.cc',
+        'webm/webm_stream_parser.h',
+        'webm/webm_tracks_parser.cc',
+        'webm/webm_tracks_parser.h',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          '..',
+        ],
+      },
+      'conditions': [
+        # Android doesn't use ffmpeg, so make the dependency conditional
+        # and exclude the sources which depend on ffmpeg.
+        ['OS != \"android\"', {
+          'dependencies': [
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+        }],
+        ['OS == \"android\"', {
+          'sources!': [
+            'base/media_posix.cc',
+            'ffmpeg/ffmpeg_common.cc',
+            'ffmpeg/ffmpeg_common.h',
+            'ffmpeg/file_protocol.cc',
+            'ffmpeg/file_protocol.h',
+            'filters/audio_file_reader.cc',
+            'filters/audio_file_reader.h',
+            'filters/bitstream_converter.cc',
+            'filters/bitstream_converter.h',
+            'filters/chunk_demuxer.cc',
+            'filters/chunk_demuxer.h',
+            'filters/chunk_demuxer_client.h',
+            'filters/ffmpeg_audio_decoder.cc',
+            'filters/ffmpeg_audio_decoder.h',
+            'filters/ffmpeg_demuxer.cc',
+            'filters/ffmpeg_demuxer.h',
+            'filters/ffmpeg_h264_bitstream_converter.cc',
+            'filters/ffmpeg_h264_bitstream_converter.h',
+            'filters/ffmpeg_glue.cc',
+            'filters/ffmpeg_glue.h',
+            'filters/ffmpeg_video_decoder.cc',
+            'filters/ffmpeg_video_decoder.h',
+            'filters/gpu_video_decoder.cc',
+            'filters/gpu_video_decoder.h',
+            'webm/webm_cluster_parser.cc',
+            'webm/webm_cluster_parser.h',
+            'webm/webm_stream_parser.cc',
+            'webm/webm_stream_parser.h',
+          ],
+        }],
+        # The below 'android' condition were added temporarily and should be
+        # removed in downstream, because there is no Java environment setup in
+        # upstream yet.
+        ['OS == \"android\"', {
+          'sources!':[
+            'audio/android/audio_track_output_android.cc',
+          ],
+          'sources':[
+            'audio/android/audio_track_output_stub_android.cc',
+          ],
+          'link_settings': {
+            'libraries': [
+              '-lOpenSLES',
+            ],
+          },
+        }],
+        ['OS==\"linux\" or OS==\"freebsd\" or OS==\"solaris\"', {
+          'link_settings': {
+            'libraries': [
+              '-lasound',
+            ],
+          },
+        }],
+        ['OS==\"openbsd\"', {
+          'sources/': [ ['exclude', '/alsa_' ],
+                        ['exclude', '/audio_manager_linux' ] ],
+          'link_settings': {
+            'libraries': [
+            ],
+          },
+        }],
+        ['OS!=\"openbsd\"', {
+          'sources!': [
+            'audio/openbsd/audio_manager_openbsd.cc',
+            'audio/openbsd/audio_manager_openbsd.h',
+          ],
+        }],
+        ['OS==\"linux\"', {
+          'variables': {
+            'conditions': [
+              ['sysroot!=\"\"', {
+                'pkg-config': '../build/linux/pkg-config-wrapper \"<(sysroot)\" \"<(target_arch)\"',
+              }, {
+                'pkg-config': 'pkg-config'
+              }],
+            ],
+          },
+          'conditions': [
+            ['use_cras == 1', {
+              'cflags': [
+                '<!@(<(pkg-config) --cflags libcras)',
+              ],
+              'link_settings': {
+                'libraries': [
+                  '<!@(<(pkg-config) --libs libcras)',
+                ],
+              },
+              'defines': [
+                'USE_CRAS',
+              ],
+            }, {  # else: use_cras == 0
+              'sources!': [
+                'audio/linux/cras_output.cc',
+                'audio/linux/cras_output.h',
+              ],
+            }],
+          ],
+        }],
+        ['os_posix == 1', {
+          'conditions': [
+            ['use_pulseaudio == 1', {
+              'cflags': [
+                '<!@(pkg-config --cflags libpulse)',
+              ],
+              'link_settings': {
+                'libraries': [
+                  '<!@(pkg-config --libs-only-l libpulse)',
+                ],
+              },
+              'defines': [
+                'USE_PULSEAUDIO',
+              ],
+            }, {  # else: use_pulseaudio == 0
+              'sources!': [
+                'audio/pulse/pulse_output.cc',
+                'audio/pulse/pulse_output.h',
+              ],
+            }],
+          ],
+        }],
+        ['os_posix == 1 and OS != \"android\"', {
+          # Video capture isn't supported in Android yet.
+          'sources!': [
+            'video/capture/video_capture_device_dummy.cc',
+            'video/capture/video_capture_device_dummy.h',
+          ],
+        }],
+        ['OS==\"mac\"', {
+          'link_settings': {
+            'libraries': [
+              '$(SDKROOT)/System/Library/Frameworks/AudioUnit.framework',
+              '$(SDKROOT)/System/Library/Frameworks/AudioToolbox.framework',
+              '$(SDKROOT)/System/Library/Frameworks/CoreAudio.framework',
+              '$(SDKROOT)/System/Library/Frameworks/CoreVideo.framework',
+              '$(SDKROOT)/System/Library/Frameworks/QTKit.framework',
+            ],
+          },
+        }],
+        ['OS==\"win\"', {
+          'sources!': [
+            'audio/pulse/pulse_output.cc',
+            'audio/pulse/pulse_output.h',
+            'video/capture/video_capture_device_dummy.cc',
+            'video/capture/video_capture_device_dummy.h',
+          ],
+        }],
+        ['proprietary_codecs==1 or branding==\"Chrome\"', {
+          'sources': [
+            'mp4/avc.cc',
+            'mp4/avc.h',
+            'mp4/box_definitions.cc',
+            'mp4/box_definitions.h',
+            'mp4/box_reader.cc',
+            'mp4/box_reader.h',
+            'mp4/cenc.cc',
+            'mp4/cenc.h',
+            'mp4/mp4_stream_parser.cc',
+            'mp4/mp4_stream_parser.h',
+            'mp4/offset_byte_queue.cc',
+            'mp4/offset_byte_queue.h',
+            'mp4/track_run_iterator.cc',
+            'mp4/track_run_iterator.h',
+          ],
+        }],
+      ],
+    },
+    {
+      'target_name': 'yuv_convert',
+      'type': 'static_library',
+      'include_dirs': [
+        '..',
+      ],
+      'conditions': [
+        ['order_profiling != 0', {
+          'target_conditions' : [
+            ['_toolset==\"target\"', {
+              'cflags!': [ '-finstrument-functions' ],
+            }],
+          ],
+        }],
+        [ 'target_arch == \"ia32\" or target_arch == \"x64\"', {
+          'dependencies': [
+            'yuv_convert_simd_x86',
+          ],
+        }],
+        [ 'target_arch == \"arm\"', {
+          'dependencies': [
+            'yuv_convert_simd_arm',
+          ],
+        }],
+      ],
+      'sources': [
+        'base/yuv_convert.cc',
+        'base/yuv_convert.h',
+      ],
+    },
+    {
+      'target_name': 'yuv_convert_simd_x86',
+      'type': 'static_library',
+      'include_dirs': [
+        '..',
+      ],
+      'sources': [
+        'base/simd/convert_rgb_to_yuv_c.cc',
+        'base/simd/convert_rgb_to_yuv_sse2.cc',
+        'base/simd/convert_rgb_to_yuv_ssse3.asm',
+        'base/simd/convert_rgb_to_yuv_ssse3.cc',
+        'base/simd/convert_rgb_to_yuv_ssse3.inc',
+        'base/simd/convert_yuv_to_rgb_c.cc',
+        'base/simd/convert_yuv_to_rgb_x86.cc',
+        'base/simd/convert_yuv_to_rgb_mmx.asm',
+        'base/simd/convert_yuv_to_rgb_mmx.inc',
+        'base/simd/convert_yuv_to_rgb_sse.asm',
+        'base/simd/filter_yuv.h',
+        'base/simd/filter_yuv_c.cc',
+        'base/simd/filter_yuv_mmx.cc',
+        'base/simd/filter_yuv_sse2.cc',
+        'base/simd/linear_scale_yuv_to_rgb_mmx.asm',
+        'base/simd/linear_scale_yuv_to_rgb_mmx.inc',
+        'base/simd/linear_scale_yuv_to_rgb_sse.asm',
+        'base/simd/scale_yuv_to_rgb_mmx.asm',
+        'base/simd/scale_yuv_to_rgb_mmx.inc',
+        'base/simd/scale_yuv_to_rgb_sse.asm',
+        'base/simd/yuv_to_rgb_table.cc',
+        'base/simd/yuv_to_rgb_table.h',
+      ],
+      'conditions': [
+        ['order_profiling != 0', {
+          'target_conditions' : [
+            ['_toolset==\"target\"', {
+              'cflags!': [ '-finstrument-functions' ],
+            }],
+          ],
+        }],
+        [ 'target_arch == \"x64\"', {
+          # Source files optimized for X64 systems.
+          'sources': [
+            'base/simd/linear_scale_yuv_to_rgb_mmx_x64.asm',
+            'base/simd/scale_yuv_to_rgb_sse2_x64.asm',
+          ],
+        }],
+        [ 'os_posix == 1 and OS != \"mac\" and OS != \"android\"', {
+          'cflags': [
+            '-msse2',
+          ],
+        }],
+        [ 'OS == \"mac\"', {
+          'configurations': {
+            'Debug': {
+              'xcode_settings': {
+                # gcc on the mac builds horribly unoptimized sse code in debug
+                # mode. Since this is rarely going to be debugged, run with full
+                # optimizations in Debug as well as Release.
+                'GCC_OPTIMIZATION_LEVEL': '3',  # -O3
+               },
+             },
+          },
+        }],
+        [ 'OS==\"win\"', {
+          'variables': {
+            'yasm_flags': [
+              '-DWIN32',
+              '-DMSVC',
+              '-DCHROMIUM',
+              '-Isimd',
+            ],
+          },
+        }],
+        [ 'OS==\"mac\"', {
+          'variables': {
+            'yasm_flags': [
+              '-DPREFIX',
+              '-DMACHO',
+              '-DCHROMIUM',
+              '-Isimd',
+            ],
+          },
+        }],
+        [ 'os_posix==1 and OS!=\"mac\"', {
+          'variables': {
+            'conditions': [
+              [ 'target_arch==\"ia32\"', {
+                'yasm_flags': [
+                  '-DX86_32',
+                  '-DELF',
+                  '-DCHROMIUM',
+                  '-Isimd',
+                ],
+              }, {
+                'yasm_flags': [
+                  '-DARCH_X86_64',
+                  '-DELF',
+                  '-DPIC',
+                  '-DCHROMIUM',
+                  '-Isimd',
+                ],
+              }],
+            ],
+          },
+        }],
+      ],
+      'variables': {
+        'yasm_output_path': '<(SHARED_INTERMEDIATE_DIR)/media',
+      },
+      'msvs_2010_disable_uldi_when_referenced': 1,
+      'includes': [
+        '../third_party/yasm/yasm_compile.gypi',
+      ],
+    },
+    {
+      'target_name': 'yuv_convert_simd_arm',
+      'type': 'static_library',
+      'include_dirs': [
+        '..',
+      ],
+      'sources': [
+        'base/simd/convert_rgb_to_yuv_c.cc',
+        'base/simd/convert_rgb_to_yuv.h',
+        'base/simd/convert_yuv_to_rgb_c.cc',
+        'base/simd/convert_yuv_to_rgb.h',
+        'base/simd/filter_yuv.h',
+        'base/simd/filter_yuv_c.cc',
+        'base/simd/yuv_to_rgb_table.cc',
+        'base/simd/yuv_to_rgb_table.h',
+      ],
+    },
+    {
+      'target_name': 'media_unittests',
+      'type': 'executable',
+      'dependencies': [
+        'media',
+        'media_test_support',
+        'yuv_convert',
+        '../base/base.gyp:base',
+        '../base/base.gyp:base_i18n',
+        '../base/base.gyp:test_support_base',
+        '../testing/gmock.gyp:gmock',
+        '../testing/gtest.gyp:gtest',
+        '../ui/ui.gyp:ui',
+      ],
+      'sources': [
+        'audio/async_socket_io_handler_unittest.cc',
+        'audio/audio_input_controller_unittest.cc',
+        'audio/audio_input_device_unittest.cc',
+        'audio/audio_input_unittest.cc',
+        'audio/audio_input_volume_unittest.cc',
+        'audio/audio_low_latency_input_output_unittest.cc',
+        'audio/audio_output_controller_unittest.cc',
+        'audio/audio_output_proxy_unittest.cc',
+        'audio/audio_parameters_unittest.cc',
+        'audio/audio_util_unittest.cc',
+        'audio/cross_process_notification_unittest.cc',
+        'audio/linux/alsa_output_unittest.cc',
+        'audio/mac/audio_low_latency_input_mac_unittest.cc',
+        'audio/mac/audio_output_mac_unittest.cc',
+        'audio/simple_sources_unittest.cc',
+        'audio/win/audio_low_latency_input_win_unittest.cc',
+        'audio/win/audio_low_latency_output_win_unittest.cc',
+        'audio/win/audio_output_win_unittest.cc',
+        'base/audio_renderer_mixer_unittest.cc',
+        'base/audio_renderer_mixer_input_unittest.cc',
+        'base/buffers_unittest.cc',
+        'base/clock_unittest.cc',
+        'base/composite_filter_unittest.cc',
+        'base/data_buffer_unittest.cc',
+        'base/decoder_buffer_unittest.cc',
+        'base/djb2_unittest.cc',
+        'base/fake_audio_render_callback.cc',
+        'base/fake_audio_render_callback.h',
+        'base/filter_collection_unittest.cc',
+        'base/h264_bitstream_converter_unittest.cc',
+        'base/pipeline_unittest.cc',
+        'base/ranges_unittest.cc',
+        'base/run_all_unittests.cc',
+        'base/seekable_buffer_unittest.cc',
+        'base/state_matrix_unittest.cc',
+        'base/test_data_util.cc',
+        'base/test_data_util.h',
+        'base/video_frame_unittest.cc',
+        'base/video_util_unittest.cc',
+        'base/yuv_convert_unittest.cc',
+        'crypto/aes_decryptor_unittest.cc',
+        'ffmpeg/ffmpeg_common_unittest.cc',
+        'filters/audio_renderer_algorithm_unittest.cc',
+        'filters/audio_renderer_impl_unittest.cc',
+        'filters/bitstream_converter_unittest.cc',
+        'filters/chunk_demuxer_unittest.cc',
+        'filters/ffmpeg_audio_decoder_unittest.cc',
+        'filters/ffmpeg_decoder_unittest.h',
+        'filters/ffmpeg_demuxer_unittest.cc',
+        'filters/ffmpeg_glue_unittest.cc',
+        'filters/ffmpeg_h264_bitstream_converter_unittest.cc',
+        'filters/ffmpeg_video_decoder_unittest.cc',
+        'filters/file_data_source_unittest.cc',
+        'filters/pipeline_integration_test.cc',
+        'filters/pipeline_integration_test_base.cc',
+        'filters/source_buffer_stream_unittest.cc',
+        'filters/video_renderer_base_unittest.cc',
+        'video/capture/video_capture_device_unittest.cc',
+        'webm/cluster_builder.cc',
+        'webm/cluster_builder.h',
+        'webm/webm_cluster_parser_unittest.cc',
+        'webm/webm_content_encodings_client_unittest.cc',
+        'webm/webm_parser_unittest.cc',
+      ],
+      'conditions': [
+        ['os_posix==1 and OS!=\"mac\"', {
+          'conditions': [
+            ['linux_use_tcmalloc==1', {
+              'dependencies': [
+                '../base/allocator/allocator.gyp:allocator',
+              ],
+            }],
+          ],
+        }],
+        ['OS != \"android\"', {
+          'dependencies': [
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+        }],
+        ['OS == \"android\"', {
+          'sources!': [
+            'audio/audio_input_volume_unittest.cc',
+            'base/test_data_util.cc',
+            'base/test_data_util.h',
+            'ffmpeg/ffmpeg_common_unittest.cc',
+            'filters/ffmpeg_audio_decoder_unittest.cc',
+            'filters/bitstream_converter_unittest.cc',
+            'filters/chunk_demuxer_unittest.cc',
+            'filters/ffmpeg_demuxer_unittest.cc',
+            'filters/ffmpeg_glue_unittest.cc',
+            'filters/ffmpeg_h264_bitstream_converter_unittest.cc',
+            'filters/ffmpeg_video_decoder_unittest.cc',
+            'filters/pipeline_integration_test.cc',
+            'filters/pipeline_integration_test_base.cc',
+            'mp4/mp4_stream_parser_unittest.cc',
+            'webm/webm_cluster_parser_unittest.cc',
+          ],
+        }],
+        ['OS == \"linux\"', {
+          'conditions': [
+            ['use_cras == 1', {
+              'sources': [
+                'audio/linux/cras_output_unittest.cc',
+              ],
+              'defines': [
+                'USE_CRAS',
+              ],
+            }],
+          ],
+        }],
+        [ 'target_arch==\"ia32\" or target_arch==\"x64\"', {
+          'sources': [
+            'base/simd/convert_rgb_to_yuv_unittest.cc',
+          ],
+        }],
+        ['proprietary_codecs==1 or branding==\"Chrome\"', {
+          'sources': [
+            'mp4/avc_unittest.cc',
+            'mp4/box_reader_unittest.cc',
+            'mp4/mp4_stream_parser_unittest.cc',
+            'mp4/offset_byte_queue_unittest.cc',
+          ],
+        }],
+      ],
+    },
+    {
+      'target_name': 'media_test_support',
+      'type': 'static_library',
+      'dependencies': [
+        'media',
+        '../base/base.gyp:base',
+        '../testing/gmock.gyp:gmock',
+        '../testing/gtest.gyp:gtest',
+      ],
+      'sources': [
+        'audio/test_audio_input_controller_factory.cc',
+        'audio/test_audio_input_controller_factory.h',
+        'base/mock_callback.cc',
+        'base/mock_callback.h',
+        'base/mock_data_source_host.cc',
+        'base/mock_data_source_host.h',
+        'base/mock_demuxer_host.cc',
+        'base/mock_demuxer_host.h',
+        'base/mock_filter_host.cc',
+        'base/mock_filter_host.h',
+        'base/mock_filters.cc',
+        'base/mock_filters.h',
+      ],
+    },
+    {
+      'target_name': 'scaler_bench',
+      'type': 'executable',
+      'dependencies': [
+        'media',
+        'yuv_convert',
+        '../base/base.gyp:base',
+        '../skia/skia.gyp:skia',
+      ],
+      'sources': [
+        'tools/scaler_bench/scaler_bench.cc',
+      ],
+    },
+    {
+      'target_name': 'qt_faststart',
+      'type': 'executable',
+      'sources': [
+        'tools/qt_faststart/qt_faststart.c'
+      ],
+    },
+    {
+      'target_name': 'seek_tester',
+      'type': 'executable',
+      'dependencies': [
+        'media',
+        '../base/base.gyp:base',
+      ],
+      'sources': [
+        'tools/seek_tester/seek_tester.cc',
+      ],
+    },
+  ],
+  'conditions': [
+    ['OS==\"win\"', {
+      'targets': [
+        {
+          'target_name': 'player_wtl',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'yuv_convert',
+            '../base/base.gyp:base',
+            '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
+            '../ui/ui.gyp:ui',
+          ],
+          'include_dirs': [
+            '<(DEPTH)/third_party/wtl/include',
+          ],
+          'sources': [
+            'tools/player_wtl/list.h',
+            'tools/player_wtl/mainfrm.h',
+            'tools/player_wtl/movie.cc',
+            'tools/player_wtl/movie.h',
+            'tools/player_wtl/player_wtl.cc',
+            'tools/player_wtl/player_wtl.rc',
+            'tools/player_wtl/props.h',
+            'tools/player_wtl/seek.h',
+            'tools/player_wtl/resource.h',
+            'tools/player_wtl/view.h',
+          ],
+          'msvs_settings': {
+            'VCLinkerTool': {
+              'SubSystem': '2',         # Set /SUBSYSTEM:WINDOWS
+            },
+          },
+          'defines': [
+            '_CRT_SECURE_NO_WARNINGS=1',
+          ],
+        },
+      ],
+    }],
+    ['OS == \"win\" or toolkit_uses_gtk == 1', {
+      'targets': [
+        {
+          'target_name': 'shader_bench',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'yuv_convert',
+            '../base/base.gyp:base',
+            '../ui/gl/gl.gyp:gl',
+          ],
+          'sources': [
+            'tools/shader_bench/shader_bench.cc',
+            'tools/shader_bench/cpu_color_painter.cc',
+            'tools/shader_bench/cpu_color_painter.h',
+            'tools/shader_bench/gpu_color_painter.cc',
+            'tools/shader_bench/gpu_color_painter.h',
+            'tools/shader_bench/gpu_painter.cc',
+            'tools/shader_bench/gpu_painter.h',
+            'tools/shader_bench/painter.cc',
+            'tools/shader_bench/painter.h',
+            'tools/shader_bench/window.cc',
+            'tools/shader_bench/window.h',
+          ],
+          'conditions': [
+            ['toolkit_uses_gtk == 1', {
+              'dependencies': [
+                '../build/linux/system.gyp:gtk',
+              ],
+              'sources': [
+                'tools/shader_bench/window_linux.cc',
+              ],
+            }],
+            ['OS==\"win\"', {
+              'dependencies': [
+                '../third_party/angle/src/build_angle.gyp:libEGL',
+                '../third_party/angle/src/build_angle.gyp:libGLESv2',
+              ],
+              'sources': [
+                'tools/shader_bench/window_win.cc',
+              ],
+            }],
+          ],
+        },
+      ],
+    }],
+    ['OS == \"linux\" and target_arch != \"arm\"', {
+      'targets': [
+        {
+          'target_name': 'tile_render_bench',
+          'type': 'executable',
+          'dependencies': [
+            '../base/base.gyp:base',
+            '../ui/gl/gl.gyp:gl',
+          ],
+          'libraries': [
+            '-lGL',
+            '-ldl',
+          ],
+          'sources': [
+            'tools/tile_render_bench/tile_render_bench.cc',
+          ],
+        },
+      ],
+    }],
+    ['os_posix == 1 and OS != \"mac\" and OS != \"android\"', {
+      'targets': [
+        {
+          'target_name': 'player_x11',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'yuv_convert',
+            '../base/base.gyp:base',
+            '../ui/gl/gl.gyp:gl',
+          ],
+          'link_settings': {
+            'libraries': [
+              '-ldl',
+              '-lX11',
+              '-lXrender',
+              '-lXext',
+            ],
+          },
+          'sources': [
+            'tools/player_x11/data_source_logger.cc',
+            'tools/player_x11/data_source_logger.h',
+            'tools/player_x11/gl_video_renderer.cc',
+            'tools/player_x11/gl_video_renderer.h',
+            'tools/player_x11/player_x11.cc',
+            'tools/player_x11/x11_video_renderer.cc',
+            'tools/player_x11/x11_video_renderer.h',
+          ],
+        },
+      ],
+    }],
+    ['OS == \"android\"', {
+      'targets': [
+        {
+          'target_name': 'player_android',
+          'type': 'static_library',
+          'sources': [
+            'base/android/media_player_bridge.cc',
+            'base/android/media_player_bridge.h',
+          ],
+          'dependencies': [
+            '../base/base.gyp:base',
+          ],
+          'include_dirs': [
+            '<(SHARED_INTERMEDIATE_DIR)/media',
+          ],
+          'actions': [
+            {
+              'action_name': 'generate-jni-headers',
+              'inputs': [
+                '../base/android/jni_generator/jni_generator.py',
+                'base/android/java/src/org/chromium/media/MediaPlayerListener.java',
+              ],
+              'outputs': [
+                '<(SHARED_INTERMEDIATE_DIR)/media/jni/media_player_listener_jni.h',
+              ],
+              'action': [
+                'python',
+                '<(DEPTH)/base/android/jni_generator/jni_generator.py',
+                '-o',
+                '<@(_inputs)',
+                '<@(_outputs)',
+              ],
+            },
+          ],
+        },
+        {
+          'target_name': 'media_java',
+          'type': 'none',
+          'dependencies': [ '../base/base.gyp:base_java' ],
+          'variables': {
+            'package_name': 'media',
+            'java_in_dir': 'base/android/java',
+          },
+          'includes': [ '../build/java.gypi' ],
+        },
+
+      ],
+    }, { # OS != \"android\"'
+      # Android does not use ffmpeg, so disable the targets which require it.
+      'targets': [
+        {
+          'target_name': 'ffmpeg_unittests',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'media_test_support',
+            '../base/base.gyp:base',
+            '../base/base.gyp:base_i18n',
+            '../base/base.gyp:test_support_base',
+            '../base/base.gyp:test_support_perf',
+            '../testing/gtest.gyp:gtest',
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+          'sources': [
+            'ffmpeg/ffmpeg_unittest.cc',
+          ],
+          'conditions': [
+            ['toolkit_uses_gtk == 1', {
+              'dependencies': [
+                # Needed for the following #include chain:
+                #   base/run_all_unittests.cc
+                #   ../base/test_suite.h
+                #   gtk/gtk.h
+                '../build/linux/system.gyp:gtk',
+              ],
+              'conditions': [
+                ['linux_use_tcmalloc==1', {
+                  'dependencies': [
+                    '../base/allocator/allocator.gyp:allocator',
+                  ],
+                }],
+              ],
+            }],
+          ],
+        },
+        {
+          'target_name': 'ffmpeg_regression_tests',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            'media_test_support',
+            '../base/base.gyp:test_support_base',
+            '../testing/gmock.gyp:gmock',
+            '../testing/gtest.gyp:gtest',
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+          'sources': [
+            'base/test_data_util.cc',
+            'base/run_all_unittests.cc',
+            'ffmpeg/ffmpeg_regression_tests.cc',
+            'filters/pipeline_integration_test_base.cc',
+          ],
+          'conditions': [
+            ['os_posix==1 and OS!=\"mac\"', {
+              'conditions': [
+                ['linux_use_tcmalloc==1', {
+                  'dependencies': [
+                    '../base/allocator/allocator.gyp:allocator',
+                  ],
+                }],
+              ],
+            }],
+          ],
+        },
+        {
+          'target_name': 'ffmpeg_tests',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            '../base/base.gyp:base',
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+          'sources': [
+            'test/ffmpeg_tests/ffmpeg_tests.cc',
+          ],
+        },
+        {
+          'target_name': 'media_bench',
+          'type': 'executable',
+          'dependencies': [
+            'media',
+            '../base/base.gyp:base',
+            '../third_party/ffmpeg/ffmpeg.gyp:ffmpeg',
+          ],
+          'sources': [
+            'tools/media_bench/media_bench.cc',
+          ],
+        },
+      ],
+    }]
+  ],
+}
+" 0 64 (face font-lock-comment-face) 64 137 (face font-lock-comment-face) 137 166 (face font-lock-comment-face) 166 171 nil 171 172 (face font-lock-string-face) 172 181 (face font-lock-keyword-face) 181 182 (face font-lock-string-face) 182 190 nil 190 191 (face font-lock-string-face) 191 204 (face font-lock-variable-name-face) 204 205 (face font-lock-string-face) 205 214 nil 214 269 (face font-lock-comment-face) 269 273 nil 273 274 (face font-lock-string-face) 274 289 (face font-lock-variable-name-face) 289 290 (face font-lock-string-face) 290 299 nil 299 365 (face font-lock-comment-face) 365 369 nil 369 370 (face font-lock-string-face) 370 379 (face font-lock-variable-name-face) 379 380 (face font-lock-string-face) 380 392 nil 392 393 (face font-lock-string-face) 393 400 (face font-lock-keyword-face) 400 401 (face font-lock-string-face) 401 417 nil 417 418 (face font-lock-string-face) 418 429 (face font-lock-keyword-face) 429 430 (face font-lock-string-face) 430 432 nil 432 433 (face font-lock-string-face) 433 438 (face font-lock-function-name-face) 438 439 (face font-lock-string-face) 439 447 nil 447 448 (face font-lock-string-face) 448 452 (face font-lock-keyword-face) 452 453 (face font-lock-string-face) 453 455 nil 455 458 (face font-lock-string-face) 458 467 (face font-lock-variable-name-face) 467 469 (face font-lock-string-face) 469 477 nil 477 478 (face font-lock-string-face) 478 490 (face font-lock-keyword-face) 490 491 (face font-lock-string-face) 491 503 nil 503 504 (face font-lock-string-face) 504 515 (face font-lock-function-name-face) 515 516 (face font-lock-string-face) 516 526 nil 526 527 (face font-lock-string-face) 527 548 (face font-lock-function-name-face) 548 549 (face font-lock-string-face) 549 559 nil 559 560 (face font-lock-string-face) 560 643 (face font-lock-function-name-face) 643 644 (face font-lock-string-face) 644 654 nil 654 655 (face font-lock-string-face) 655 696 (face font-lock-function-name-face) 696 697 (face font-lock-string-face) 697 707 nil 707 708 (face font-lock-string-face) 708 735 (face font-lock-function-name-face) 735 736 (face font-lock-string-face) 736 746 nil 746 747 (face font-lock-string-face) 747 784 (face font-lock-function-name-face) 784 785 (face font-lock-string-face) 785 795 nil 795 796 (face font-lock-string-face) 796 811 (face font-lock-function-name-face) 811 812 (face font-lock-string-face) 812 829 nil 829 830 (face font-lock-string-face) 830 837 (face font-lock-keyword-face) 837 838 (face font-lock-string-face) 838 850 nil 850 851 (face font-lock-string-face) 851 871 (face font-lock-preprocessor-face) 871 872 (face font-lock-string-face) 872 889 nil 889 890 (face font-lock-string-face) 890 902 (face font-lock-keyword-face) 902 903 (face font-lock-string-face) 903 915 nil 915 916 (face font-lock-string-face) 916 918 (face font-lock-constant-face) 918 919 (face font-lock-string-face) 919 936 nil 936 937 (face font-lock-string-face) 937 944 (face font-lock-keyword-face) 944 945 (face font-lock-string-face) 945 957 nil 957 958 (face font-lock-string-face) 958 996 (face font-lock-constant-face) 996 997 (face font-lock-string-face) 997 1007 nil 1007 1008 (face font-lock-string-face) 1008 1045 (face font-lock-constant-face) 1045 1046 (face font-lock-string-face) 1046 1056 nil 1056 1057 (face font-lock-string-face) 1057 1100 (face font-lock-constant-face) 1100 1101 (face font-lock-string-face) 1101 1111 nil 1111 1112 (face font-lock-string-face) 1112 1154 (face font-lock-constant-face) 1154 1155 (face font-lock-string-face) 1155 1165 nil 1165 1166 (face font-lock-string-face) 1166 1197 (face font-lock-constant-face) 1197 1198 (face font-lock-string-face) 1198 1208 nil 1208 1209 (face font-lock-string-face) 1209 1239 (face font-lock-constant-face) 1239 1240 (face font-lock-string-face) 1240 1250 nil 1250 1251 (face font-lock-string-face) 1251 1283 (face font-lock-constant-face) 1283 1284 (face font-lock-string-face) 1284 1294 nil 1294 1295 (face font-lock-string-face) 1295 1326 (face font-lock-constant-face) 1326 1327 (face font-lock-string-face) 1327 1337 nil 1337 1338 (face font-lock-string-face) 1338 1369 (face font-lock-constant-face) 1369 1370 (face font-lock-string-face) 1370 1380 nil 1380 1381 (face font-lock-string-face) 1381 1419 (face font-lock-constant-face) 1419 1420 (face font-lock-string-face) 1420 1430 nil 1430 1431 (face font-lock-string-face) 1431 1467 (face font-lock-constant-face) 1467 1468 (face font-lock-string-face) 1468 1478 nil 1478 1479 (face font-lock-string-face) 1479 1507 (face font-lock-constant-face) 1507 1508 (face font-lock-string-face) 1508 1518 nil 1518 1519 (face font-lock-string-face) 1519 1546 (face font-lock-constant-face) 1546 1547 (face font-lock-string-face) 1547 1557 nil 1557 1558 (face font-lock-string-face) 1558 1574 (face font-lock-constant-face) 1574 1575 (face font-lock-string-face) 1575 1585 nil 1585 1586 (face font-lock-string-face) 1586 1617 (face font-lock-constant-face) 1617 1618 (face font-lock-string-face) 1618 1628 nil 1628 1629 (face font-lock-string-face) 1629 1659 (face font-lock-constant-face) 1659 1660 (face font-lock-string-face) 1660 1670 nil 1670 1671 (face font-lock-string-face) 1671 1703 (face font-lock-constant-face) 1703 1704 (face font-lock-string-face) 1704 1714 nil 1714 1715 (face font-lock-string-face) 1715 1746 (face font-lock-constant-face) 1746 1747 (face font-lock-string-face) 1747 1757 nil 1757 1758 (face font-lock-string-face) 1758 1784 (face font-lock-constant-face) 1784 1785 (face font-lock-string-face) 1785 1795 nil 1795 1796 (face font-lock-string-face) 1796 1821 (face font-lock-constant-face) 1821 1822 (face font-lock-string-face) 1822 1832 nil 1832 1833 (face font-lock-string-face) 1833 1855 (face font-lock-constant-face) 1855 1856 (face font-lock-string-face) 1856 1866 nil 1866 1867 (face font-lock-string-face) 1867 1888 (face font-lock-constant-face) 1888 1889 (face font-lock-string-face) 1889 1899 nil 1899 1900 (face font-lock-string-face) 1900 1927 (face font-lock-constant-face) 1927 1928 (face font-lock-string-face) 1928 1938 nil 1938 1939 (face font-lock-string-face) 1939 1965 (face font-lock-constant-face) 1965 1966 (face font-lock-string-face) 1966 1976 nil 1976 1977 (face font-lock-string-face) 1977 2009 (face font-lock-constant-face) 2009 2010 (face font-lock-string-face) 2010 2020 nil 2020 2021 (face font-lock-string-face) 2021 2052 (face font-lock-constant-face) 2052 2053 (face font-lock-string-face) 2053 2063 nil 2063 2064 (face font-lock-string-face) 2064 2096 (face font-lock-constant-face) 2096 2097 (face font-lock-string-face) 2097 2107 nil 2107 2108 (face font-lock-string-face) 2108 2139 (face font-lock-constant-face) 2139 2140 (face font-lock-string-face) 2140 2150 nil 2150 2151 (face font-lock-string-face) 2151 2188 (face font-lock-constant-face) 2188 2189 (face font-lock-string-face) 2189 2199 nil 2199 2200 (face font-lock-string-face) 2200 2236 (face font-lock-constant-face) 2236 2237 (face font-lock-string-face) 2237 2247 nil 2247 2248 (face font-lock-string-face) 2248 2275 (face font-lock-constant-face) 2275 2276 (face font-lock-string-face) 2276 2286 nil 2286 2287 (face font-lock-string-face) 2287 2313 (face font-lock-constant-face) 2313 2314 (face font-lock-string-face) 2314 2324 nil 2324 2325 (face font-lock-string-face) 2325 2352 (face font-lock-constant-face) 2352 2353 (face font-lock-string-face) 2353 2363 nil 2363 2364 (face font-lock-string-face) 2364 2390 (face font-lock-constant-face) 2390 2391 (face font-lock-string-face) 2391 2401 nil 2401 2402 (face font-lock-string-face) 2402 2427 (face font-lock-constant-face) 2427 2428 (face font-lock-string-face) 2428 2438 nil 2438 2439 (face font-lock-string-face) 2439 2463 (face font-lock-constant-face) 2463 2464 (face font-lock-string-face) 2464 2474 nil 2474 2475 (face font-lock-string-face) 2475 2494 (face font-lock-constant-face) 2494 2495 (face font-lock-string-face) 2495 2505 nil 2505 2506 (face font-lock-string-face) 2506 2524 (face font-lock-constant-face) 2524 2525 (face font-lock-string-face) 2525 2535 nil 2535 2536 (face font-lock-string-face) 2536 2571 (face font-lock-constant-face) 2571 2572 (face font-lock-string-face) 2572 2582 nil 2582 2583 (face font-lock-string-face) 2583 2617 (face font-lock-constant-face) 2617 2618 (face font-lock-string-face) 2618 2628 nil 2628 2629 (face font-lock-string-face) 2629 2668 (face font-lock-constant-face) 2668 2669 (face font-lock-string-face) 2669 2679 nil 2679 2680 (face font-lock-string-face) 2680 2721 (face font-lock-constant-face) 2721 2722 (face font-lock-string-face) 2722 2732 nil 2732 2733 (face font-lock-string-face) 2733 2765 (face font-lock-constant-face) 2765 2766 (face font-lock-string-face) 2766 2776 nil 2776 2777 (face font-lock-string-face) 2777 2808 (face font-lock-constant-face) 2808 2809 (face font-lock-string-face) 2809 2819 nil 2819 2820 (face font-lock-string-face) 2820 2853 (face font-lock-constant-face) 2853 2854 (face font-lock-string-face) 2854 2864 nil 2864 2865 (face font-lock-string-face) 2865 2897 (face font-lock-constant-face) 2897 2898 (face font-lock-string-face) 2898 2908 nil 2908 2909 (face font-lock-string-face) 2909 2943 (face font-lock-constant-face) 2943 2944 (face font-lock-string-face) 2944 2954 nil 2954 2955 (face font-lock-string-face) 2955 2988 (face font-lock-constant-face) 2988 2989 (face font-lock-string-face) 2989 2999 nil 2999 3000 (face font-lock-string-face) 3000 3025 (face font-lock-constant-face) 3025 3026 (face font-lock-string-face) 3026 3036 nil 3036 3037 (face font-lock-string-face) 3037 3061 (face font-lock-constant-face) 3061 3062 (face font-lock-string-face) 3062 3072 nil 3072 3073 (face font-lock-string-face) 3073 3099 (face font-lock-constant-face) 3099 3100 (face font-lock-string-face) 3100 3110 nil 3110 3111 (face font-lock-string-face) 3111 3136 (face font-lock-constant-face) 3136 3137 (face font-lock-string-face) 3137 3147 nil 3147 3148 (face font-lock-string-face) 3148 3172 (face font-lock-constant-face) 3172 3173 (face font-lock-string-face) 3173 3183 nil 3183 3184 (face font-lock-string-face) 3184 3207 (face font-lock-constant-face) 3207 3208 (face font-lock-string-face) 3208 3218 nil 3218 3219 (face font-lock-string-face) 3219 3246 (face font-lock-constant-face) 3246 3247 (face font-lock-string-face) 3247 3257 nil 3257 3258 (face font-lock-string-face) 3258 3284 (face font-lock-constant-face) 3284 3285 (face font-lock-string-face) 3285 3295 nil 3295 3296 (face font-lock-string-face) 3296 3322 (face font-lock-constant-face) 3322 3323 (face font-lock-string-face) 3323 3333 nil 3333 3334 (face font-lock-string-face) 3334 3359 (face font-lock-constant-face) 3359 3360 (face font-lock-string-face) 3360 3370 nil 3370 3371 (face font-lock-string-face) 3371 3409 (face font-lock-constant-face) 3409 3410 (face font-lock-string-face) 3410 3420 nil 3420 3421 (face font-lock-string-face) 3421 3458 (face font-lock-constant-face) 3458 3459 (face font-lock-string-face) 3459 3469 nil 3469 3470 (face font-lock-string-face) 3470 3498 (face font-lock-constant-face) 3498 3499 (face font-lock-string-face) 3499 3509 nil 3509 3510 (face font-lock-string-face) 3510 3537 (face font-lock-constant-face) 3537 3538 (face font-lock-string-face) 3538 3548 nil 3548 3549 (face font-lock-string-face) 3549 3589 (face font-lock-constant-face) 3589 3590 (face font-lock-string-face) 3590 3600 nil 3600 3601 (face font-lock-string-face) 3601 3640 (face font-lock-constant-face) 3640 3641 (face font-lock-string-face) 3641 3651 nil 3651 3652 (face font-lock-string-face) 3652 3693 (face font-lock-constant-face) 3693 3694 (face font-lock-string-face) 3694 3704 nil 3704 3705 (face font-lock-string-face) 3705 3745 (face font-lock-constant-face) 3745 3746 (face font-lock-string-face) 3746 3756 nil 3756 3757 (face font-lock-string-face) 3757 3787 (face font-lock-constant-face) 3787 3788 (face font-lock-string-face) 3788 3798 nil 3798 3799 (face font-lock-string-face) 3799 3828 (face font-lock-constant-face) 3828 3829 (face font-lock-string-face) 3829 3839 nil 3839 3840 (face font-lock-string-face) 3840 3869 (face font-lock-constant-face) 3869 3870 (face font-lock-string-face) 3870 3880 nil 3880 3881 (face font-lock-string-face) 3881 3909 (face font-lock-constant-face) 3909 3910 (face font-lock-string-face) 3910 3920 nil 3920 3921 (face font-lock-string-face) 3921 3945 (face font-lock-constant-face) 3945 3946 (face font-lock-string-face) 3946 3956 nil 3956 3957 (face font-lock-string-face) 3957 3980 (face font-lock-constant-face) 3980 3981 (face font-lock-string-face) 3981 3991 nil 3991 3992 (face font-lock-string-face) 3992 4019 (face font-lock-constant-face) 4019 4020 (face font-lock-string-face) 4020 4030 nil 4030 4031 (face font-lock-string-face) 4031 4057 (face font-lock-constant-face) 4057 4058 (face font-lock-string-face) 4058 4068 nil 4068 4069 (face font-lock-string-face) 4069 4090 (face font-lock-constant-face) 4090 4091 (face font-lock-string-face) 4091 4101 nil 4101 4102 (face font-lock-string-face) 4102 4122 (face font-lock-constant-face) 4122 4123 (face font-lock-string-face) 4123 4133 nil 4133 4134 (face font-lock-string-face) 4134 4157 (face font-lock-constant-face) 4157 4158 (face font-lock-string-face) 4158 4168 nil 4168 4169 (face font-lock-string-face) 4169 4191 (face font-lock-constant-face) 4191 4192 (face font-lock-string-face) 4192 4202 nil 4202 4203 (face font-lock-string-face) 4203 4243 (face font-lock-constant-face) 4243 4244 (face font-lock-string-face) 4244 4254 nil 4254 4255 (face font-lock-string-face) 4255 4294 (face font-lock-constant-face) 4294 4295 (face font-lock-string-face) 4295 4305 nil 4305 4306 (face font-lock-string-face) 4306 4347 (face font-lock-constant-face) 4347 4348 (face font-lock-string-face) 4348 4358 nil 4358 4359 (face font-lock-string-face) 4359 4399 (face font-lock-constant-face) 4399 4400 (face font-lock-string-face) 4400 4410 nil 4410 4411 (face font-lock-string-face) 4411 4441 (face font-lock-constant-face) 4441 4442 (face font-lock-string-face) 4442 4452 nil 4452 4453 (face font-lock-string-face) 4453 4482 (face font-lock-constant-face) 4482 4483 (face font-lock-string-face) 4483 4493 nil 4493 4494 (face font-lock-string-face) 4494 4523 (face font-lock-constant-face) 4523 4524 (face font-lock-string-face) 4524 4534 nil 4534 4535 (face font-lock-string-face) 4535 4563 (face font-lock-constant-face) 4563 4564 (face font-lock-string-face) 4564 4574 nil 4574 4575 (face font-lock-string-face) 4575 4610 (face font-lock-constant-face) 4610 4611 (face font-lock-string-face) 4611 4621 nil 4621 4622 (face font-lock-string-face) 4622 4656 (face font-lock-constant-face) 4656 4657 (face font-lock-string-face) 4657 4667 nil 4667 4668 (face font-lock-string-face) 4668 4697 (face font-lock-constant-face) 4697 4698 (face font-lock-string-face) 4698 4708 nil 4708 4709 (face font-lock-string-face) 4709 4737 (face font-lock-constant-face) 4737 4738 (face font-lock-string-face) 4738 4748 nil 4748 4749 (face font-lock-string-face) 4749 4780 (face font-lock-constant-face) 4780 4781 (face font-lock-string-face) 4781 4791 nil 4791 4792 (face font-lock-string-face) 4792 4822 (face font-lock-constant-face) 4822 4823 (face font-lock-string-face) 4823 4833 nil 4833 4834 (face font-lock-string-face) 4834 4869 (face font-lock-constant-face) 4869 4870 (face font-lock-string-face) 4870 4880 nil 4880 4881 (face font-lock-string-face) 4881 4915 (face font-lock-constant-face) 4915 4916 (face font-lock-string-face) 4916 4926 nil 4926 4927 (face font-lock-string-face) 4927 4948 (face font-lock-constant-face) 4948 4949 (face font-lock-string-face) 4949 4959 nil 4959 4960 (face font-lock-string-face) 4960 4980 (face font-lock-constant-face) 4980 4981 (face font-lock-string-face) 4981 4991 nil 4991 4992 (face font-lock-string-face) 4992 5020 (face font-lock-constant-face) 5020 5021 (face font-lock-string-face) 5021 5031 nil 5031 5032 (face font-lock-string-face) 5032 5059 (face font-lock-constant-face) 5059 5060 (face font-lock-string-face) 5060 5070 nil 5070 5071 (face font-lock-string-face) 5071 5092 (face font-lock-constant-face) 5092 5093 (face font-lock-string-face) 5093 5103 nil 5103 5104 (face font-lock-string-face) 5104 5132 (face font-lock-constant-face) 5132 5133 (face font-lock-string-face) 5133 5143 nil 5143 5144 (face font-lock-string-face) 5144 5171 (face font-lock-constant-face) 5171 5172 (face font-lock-string-face) 5172 5182 nil 5182 5183 (face font-lock-string-face) 5183 5217 (face font-lock-constant-face) 5217 5218 (face font-lock-string-face) 5218 5228 nil 5228 5229 (face font-lock-string-face) 5229 5262 (face font-lock-constant-face) 5262 5263 (face font-lock-string-face) 5263 5273 nil 5273 5274 (face font-lock-string-face) 5274 5297 (face font-lock-constant-face) 5297 5298 (face font-lock-string-face) 5298 5308 nil 5308 5309 (face font-lock-string-face) 5309 5324 (face font-lock-constant-face) 5324 5325 (face font-lock-string-face) 5325 5335 nil 5335 5336 (face font-lock-string-face) 5336 5350 (face font-lock-constant-face) 5350 5351 (face font-lock-string-face) 5351 5361 nil 5361 5362 (face font-lock-string-face) 5362 5380 (face font-lock-constant-face) 5380 5381 (face font-lock-string-face) 5381 5391 nil 5391 5392 (face font-lock-string-face) 5392 5409 (face font-lock-constant-face) 5409 5410 (face font-lock-string-face) 5410 5420 nil 5420 5421 (face font-lock-string-face) 5421 5443 (face font-lock-constant-face) 5443 5444 (face font-lock-string-face) 5444 5454 nil 5454 5455 (face font-lock-string-face) 5455 5476 (face font-lock-constant-face) 5476 5477 (face font-lock-string-face) 5477 5487 nil 5487 5488 (face font-lock-string-face) 5488 5501 (face font-lock-constant-face) 5501 5502 (face font-lock-string-face) 5502 5512 nil 5512 5513 (face font-lock-string-face) 5513 5525 (face font-lock-constant-face) 5525 5526 (face font-lock-string-face) 5526 5536 nil 5536 5537 (face font-lock-string-face) 5537 5561 (face font-lock-constant-face) 5561 5562 (face font-lock-string-face) 5562 5572 nil 5572 5573 (face font-lock-string-face) 5573 5596 (face font-lock-constant-face) 5596 5597 (face font-lock-string-face) 5597 5607 nil 5607 5608 (face font-lock-string-face) 5608 5627 (face font-lock-constant-face) 5627 5628 (face font-lock-string-face) 5628 5638 nil 5638 5639 (face font-lock-string-face) 5639 5657 (face font-lock-constant-face) 5657 5658 (face font-lock-string-face) 5658 5668 nil 5668 5669 (face font-lock-string-face) 5669 5688 (face font-lock-constant-face) 5688 5689 (face font-lock-string-face) 5689 5699 nil 5699 5700 (face font-lock-string-face) 5700 5718 (face font-lock-constant-face) 5718 5719 (face font-lock-string-face) 5719 5729 nil 5729 5730 (face font-lock-string-face) 5730 5752 (face font-lock-constant-face) 5752 5753 (face font-lock-string-face) 5753 5763 nil 5763 5764 (face font-lock-string-face) 5764 5785 (face font-lock-constant-face) 5785 5786 (face font-lock-string-face) 5786 5796 nil 5796 5797 (face font-lock-string-face) 5797 5819 (face font-lock-constant-face) 5819 5820 (face font-lock-string-face) 5820 5830 nil 5830 5831 (face font-lock-string-face) 5831 5852 (face font-lock-constant-face) 5852 5853 (face font-lock-string-face) 5853 5863 nil 5863 5864 (face font-lock-string-face) 5864 5880 (face font-lock-constant-face) 5880 5881 (face font-lock-string-face) 5881 5891 nil 5891 5892 (face font-lock-string-face) 5892 5915 (face font-lock-constant-face) 5915 5916 (face font-lock-string-face) 5916 5926 nil 5926 5927 (face font-lock-string-face) 5927 5942 (face font-lock-constant-face) 5942 5943 (face font-lock-string-face) 5943 5953 nil 5953 5954 (face font-lock-string-face) 5954 5968 (face font-lock-constant-face) 5968 5969 (face font-lock-string-face) 5969 5979 nil 5979 5980 (face font-lock-string-face) 5980 6002 (face font-lock-constant-face) 6002 6003 (face font-lock-string-face) 6003 6013 nil 6013 6014 (face font-lock-string-face) 6014 6035 (face font-lock-constant-face) 6035 6036 (face font-lock-string-face) 6036 6046 nil 6046 6047 (face font-lock-string-face) 6047 6059 (face font-lock-constant-face) 6059 6060 (face font-lock-string-face) 6060 6070 nil 6070 6071 (face font-lock-string-face) 6071 6082 (face font-lock-constant-face) 6082 6083 (face font-lock-string-face) 6083 6093 nil 6093 6094 (face font-lock-string-face) 6094 6119 (face font-lock-constant-face) 6119 6120 (face font-lock-string-face) 6120 6130 nil 6130 6131 (face font-lock-string-face) 6131 6155 (face font-lock-constant-face) 6155 6156 (face font-lock-string-face) 6156 6166 nil 6166 6167 (face font-lock-string-face) 6167 6185 (face font-lock-constant-face) 6185 6186 (face font-lock-string-face) 6186 6196 nil 6196 6197 (face font-lock-string-face) 6197 6212 (face font-lock-constant-face) 6212 6213 (face font-lock-string-face) 6213 6223 nil 6223 6224 (face font-lock-string-face) 6224 6238 (face font-lock-constant-face) 6238 6239 (face font-lock-string-face) 6239 6249 nil 6249 6250 (face font-lock-string-face) 6250 6282 (face font-lock-constant-face) 6282 6283 (face font-lock-string-face) 6283 6293 nil 6293 6294 (face font-lock-string-face) 6294 6325 (face font-lock-constant-face) 6325 6326 (face font-lock-string-face) 6326 6336 nil 6336 6337 (face font-lock-string-face) 6337 6349 (face font-lock-constant-face) 6349 6350 (face font-lock-string-face) 6350 6360 nil 6360 6361 (face font-lock-string-face) 6361 6382 (face font-lock-constant-face) 6382 6383 (face font-lock-string-face) 6383 6393 nil 6393 6394 (face font-lock-string-face) 6394 6413 (face font-lock-constant-face) 6413 6414 (face font-lock-string-face) 6414 6424 nil 6424 6425 (face font-lock-string-face) 6425 6442 (face font-lock-constant-face) 6442 6443 (face font-lock-string-face) 6443 6453 nil 6453 6454 (face font-lock-string-face) 6454 6470 (face font-lock-constant-face) 6470 6471 (face font-lock-string-face) 6471 6481 nil 6481 6482 (face font-lock-string-face) 6482 6504 (face font-lock-constant-face) 6504 6505 (face font-lock-string-face) 6505 6515 nil 6515 6516 (face font-lock-string-face) 6516 6535 (face font-lock-constant-face) 6535 6536 (face font-lock-string-face) 6536 6546 nil 6546 6547 (face font-lock-string-face) 6547 6569 (face font-lock-constant-face) 6569 6570 (face font-lock-string-face) 6570 6580 nil 6580 6581 (face font-lock-string-face) 6581 6602 (face font-lock-constant-face) 6602 6603 (face font-lock-string-face) 6603 6613 nil 6613 6614 (face font-lock-string-face) 6614 6631 (face font-lock-constant-face) 6631 6632 (face font-lock-string-face) 6632 6642 nil 6642 6643 (face font-lock-string-face) 6643 6671 (face font-lock-constant-face) 6671 6672 (face font-lock-string-face) 6672 6682 nil 6682 6683 (face font-lock-string-face) 6683 6710 (face font-lock-constant-face) 6710 6711 (face font-lock-string-face) 6711 6721 nil 6721 6722 (face font-lock-string-face) 6722 6738 (face font-lock-constant-face) 6738 6739 (face font-lock-string-face) 6739 6749 nil 6749 6750 (face font-lock-string-face) 6750 6765 (face font-lock-constant-face) 6765 6766 (face font-lock-string-face) 6766 6776 nil 6776 6777 (face font-lock-string-face) 6777 6800 (face font-lock-constant-face) 6800 6801 (face font-lock-string-face) 6801 6811 nil 6811 6812 (face font-lock-string-face) 6812 6834 (face font-lock-constant-face) 6834 6835 (face font-lock-string-face) 6835 6845 nil 6845 6846 (face font-lock-string-face) 6846 6860 (face font-lock-constant-face) 6860 6861 (face font-lock-string-face) 6861 6871 nil 6871 6872 (face font-lock-string-face) 6872 6885 (face font-lock-constant-face) 6885 6886 (face font-lock-string-face) 6886 6896 nil 6896 6897 (face font-lock-string-face) 6897 6920 (face font-lock-constant-face) 6920 6921 (face font-lock-string-face) 6921 6931 nil 6931 6932 (face font-lock-string-face) 6932 6954 (face font-lock-constant-face) 6954 6955 (face font-lock-string-face) 6955 6965 nil 6965 6966 (face font-lock-string-face) 6966 6986 (face font-lock-constant-face) 6986 6987 (face font-lock-string-face) 6987 6997 nil 6997 6998 (face font-lock-string-face) 6998 7017 (face font-lock-constant-face) 7017 7018 (face font-lock-string-face) 7018 7028 nil 7028 7029 (face font-lock-string-face) 7029 7050 (face font-lock-constant-face) 7050 7051 (face font-lock-string-face) 7051 7061 nil 7061 7062 (face font-lock-string-face) 7062 7082 (face font-lock-constant-face) 7082 7083 (face font-lock-string-face) 7083 7093 nil 7093 7094 (face font-lock-string-face) 7094 7122 (face font-lock-constant-face) 7122 7123 (face font-lock-string-face) 7123 7133 nil 7133 7134 (face font-lock-string-face) 7134 7161 (face font-lock-constant-face) 7161 7162 (face font-lock-string-face) 7162 7172 nil 7172 7173 (face font-lock-string-face) 7173 7194 (face font-lock-constant-face) 7194 7195 (face font-lock-string-face) 7195 7205 nil 7205 7206 (face font-lock-string-face) 7206 7226 (face font-lock-constant-face) 7226 7227 (face font-lock-string-face) 7227 7237 nil 7237 7238 (face font-lock-string-face) 7238 7266 (face font-lock-constant-face) 7266 7267 (face font-lock-string-face) 7267 7277 nil 7277 7278 (face font-lock-string-face) 7278 7305 (face font-lock-constant-face) 7305 7306 (face font-lock-string-face) 7306 7316 nil 7316 7317 (face font-lock-string-face) 7317 7336 (face font-lock-constant-face) 7336 7337 (face font-lock-string-face) 7337 7347 nil 7347 7348 (face font-lock-string-face) 7348 7366 (face font-lock-constant-face) 7366 7367 (face font-lock-string-face) 7367 7377 nil 7377 7378 (face font-lock-string-face) 7378 7399 (face font-lock-constant-face) 7399 7400 (face font-lock-string-face) 7400 7410 nil 7410 7411 (face font-lock-string-face) 7411 7429 (face font-lock-constant-face) 7429 7430 (face font-lock-string-face) 7430 7440 nil 7440 7441 (face font-lock-string-face) 7441 7458 (face font-lock-constant-face) 7458 7459 (face font-lock-string-face) 7459 7469 nil 7469 7470 (face font-lock-string-face) 7470 7493 (face font-lock-constant-face) 7493 7494 (face font-lock-string-face) 7494 7504 nil 7504 7505 (face font-lock-string-face) 7505 7527 (face font-lock-constant-face) 7527 7528 (face font-lock-string-face) 7528 7538 nil 7538 7539 (face font-lock-string-face) 7539 7562 (face font-lock-constant-face) 7562 7563 (face font-lock-string-face) 7563 7573 nil 7573 7574 (face font-lock-string-face) 7574 7596 (face font-lock-constant-face) 7596 7597 (face font-lock-string-face) 7597 7607 nil 7607 7608 (face font-lock-string-face) 7608 7631 (face font-lock-constant-face) 7631 7632 (face font-lock-string-face) 7632 7642 nil 7642 7643 (face font-lock-string-face) 7643 7665 (face font-lock-constant-face) 7665 7666 (face font-lock-string-face) 7666 7676 nil 7676 7677 (face font-lock-string-face) 7677 7705 (face font-lock-constant-face) 7705 7706 (face font-lock-string-face) 7706 7716 nil 7716 7717 (face font-lock-string-face) 7717 7744 (face font-lock-constant-face) 7744 7745 (face font-lock-string-face) 7745 7755 nil 7755 7756 (face font-lock-string-face) 7756 7791 (face font-lock-constant-face) 7791 7792 (face font-lock-string-face) 7792 7802 nil 7802 7803 (face font-lock-string-face) 7803 7837 (face font-lock-constant-face) 7837 7838 (face font-lock-string-face) 7838 7848 nil 7848 7849 (face font-lock-string-face) 7849 7879 (face font-lock-constant-face) 7879 7880 (face font-lock-string-face) 7880 7890 nil 7890 7891 (face font-lock-string-face) 7891 7920 (face font-lock-constant-face) 7920 7921 (face font-lock-string-face) 7921 7931 nil 7931 7932 (face font-lock-string-face) 7932 7962 (face font-lock-constant-face) 7962 7963 (face font-lock-string-face) 7963 7973 nil 7973 7974 (face font-lock-string-face) 7974 8003 (face font-lock-constant-face) 8003 8004 (face font-lock-string-face) 8004 8014 nil 8014 8015 (face font-lock-string-face) 8015 8039 (face font-lock-constant-face) 8039 8040 (face font-lock-string-face) 8040 8050 nil 8050 8051 (face font-lock-string-face) 8051 8074 (face font-lock-constant-face) 8074 8075 (face font-lock-string-face) 8075 8085 nil 8085 8086 (face font-lock-string-face) 8086 8116 (face font-lock-constant-face) 8116 8117 (face font-lock-string-face) 8117 8127 nil 8127 8128 (face font-lock-string-face) 8128 8152 (face font-lock-constant-face) 8152 8153 (face font-lock-string-face) 8153 8163 nil 8163 8164 (face font-lock-string-face) 8164 8187 (face font-lock-constant-face) 8187 8188 (face font-lock-string-face) 8188 8198 nil 8198 8199 (face font-lock-string-face) 8199 8230 (face font-lock-constant-face) 8230 8231 (face font-lock-string-face) 8231 8241 nil 8241 8242 (face font-lock-string-face) 8242 8272 (face font-lock-constant-face) 8272 8273 (face font-lock-string-face) 8273 8283 nil 8283 8284 (face font-lock-string-face) 8284 8309 (face font-lock-constant-face) 8309 8310 (face font-lock-string-face) 8310 8320 nil 8320 8321 (face font-lock-string-face) 8321 8345 (face font-lock-constant-face) 8345 8346 (face font-lock-string-face) 8346 8356 nil 8356 8357 (face font-lock-string-face) 8357 8399 (face font-lock-constant-face) 8399 8400 (face font-lock-string-face) 8400 8410 nil 8410 8411 (face font-lock-string-face) 8411 8452 (face font-lock-constant-face) 8452 8453 (face font-lock-string-face) 8453 8463 nil 8463 8464 (face font-lock-string-face) 8464 8486 (face font-lock-constant-face) 8486 8487 (face font-lock-string-face) 8487 8497 nil 8497 8498 (face font-lock-string-face) 8498 8519 (face font-lock-constant-face) 8519 8520 (face font-lock-string-face) 8520 8530 nil 8530 8531 (face font-lock-string-face) 8531 8562 (face font-lock-constant-face) 8562 8563 (face font-lock-string-face) 8563 8573 nil 8573 8574 (face font-lock-string-face) 8574 8604 (face font-lock-constant-face) 8604 8605 (face font-lock-string-face) 8605 8615 nil 8615 8616 (face font-lock-string-face) 8616 8643 (face font-lock-constant-face) 8643 8644 (face font-lock-string-face) 8644 8654 nil 8654 8655 (face font-lock-string-face) 8655 8681 (face font-lock-constant-face) 8681 8682 (face font-lock-string-face) 8682 8692 nil 8692 8693 (face font-lock-string-face) 8693 8721 (face font-lock-constant-face) 8721 8722 (face font-lock-string-face) 8722 8732 nil 8732 8733 (face font-lock-string-face) 8733 8760 (face font-lock-constant-face) 8760 8761 (face font-lock-string-face) 8761 8771 nil 8771 8772 (face font-lock-string-face) 8772 8805 (face font-lock-constant-face) 8805 8806 (face font-lock-string-face) 8806 8816 nil 8816 8817 (face font-lock-string-face) 8817 8849 (face font-lock-constant-face) 8849 8850 (face font-lock-string-face) 8850 8860 nil 8860 8861 (face font-lock-string-face) 8861 8892 (face font-lock-constant-face) 8892 8893 (face font-lock-string-face) 8893 8903 nil 8903 8904 (face font-lock-string-face) 8904 8934 (face font-lock-constant-face) 8934 8935 (face font-lock-string-face) 8935 8945 nil 8945 8946 (face font-lock-string-face) 8946 8978 (face font-lock-constant-face) 8978 8979 (face font-lock-string-face) 8979 8989 nil 8989 8990 (face font-lock-string-face) 8990 9021 (face font-lock-constant-face) 9021 9022 (face font-lock-string-face) 9022 9032 nil 9032 9033 (face font-lock-string-face) 9033 9063 (face font-lock-constant-face) 9063 9064 (face font-lock-string-face) 9064 9074 nil 9074 9075 (face font-lock-string-face) 9075 9104 (face font-lock-constant-face) 9104 9105 (face font-lock-string-face) 9105 9115 nil 9115 9116 (face font-lock-string-face) 9116 9158 (face font-lock-constant-face) 9158 9159 (face font-lock-string-face) 9159 9169 nil 9169 9170 (face font-lock-string-face) 9170 9211 (face font-lock-constant-face) 9211 9212 (face font-lock-string-face) 9212 9222 nil 9222 9223 (face font-lock-string-face) 9223 9272 (face font-lock-constant-face) 9272 9273 (face font-lock-string-face) 9273 9283 nil 9283 9284 (face font-lock-string-face) 9284 9332 (face font-lock-constant-face) 9332 9333 (face font-lock-string-face) 9333 9343 nil 9343 9344 (face font-lock-string-face) 9344 9388 (face font-lock-constant-face) 9388 9389 (face font-lock-string-face) 9389 9399 nil 9399 9400 (face font-lock-string-face) 9400 9445 (face font-lock-constant-face) 9445 9446 (face font-lock-string-face) 9446 9456 nil 9456 9457 (face font-lock-string-face) 9457 9507 (face font-lock-constant-face) 9507 9508 (face font-lock-string-face) 9508 9518 nil 9518 9519 (face font-lock-string-face) 9519 9570 (face font-lock-constant-face) 9570 9571 (face font-lock-string-face) 9571 9581 nil 9581 9582 (face font-lock-string-face) 9582 9611 (face font-lock-constant-face) 9611 9612 (face font-lock-string-face) 9612 9622 nil 9622 9623 (face font-lock-string-face) 9623 9659 (face font-lock-constant-face) 9659 9660 (face font-lock-string-face) 9660 9670 nil 9670 9671 (face font-lock-string-face) 9671 9714 (face font-lock-constant-face) 9714 9715 (face font-lock-string-face) 9715 9725 nil 9725 9726 (face font-lock-string-face) 9726 9768 (face font-lock-constant-face) 9768 9769 (face font-lock-string-face) 9769 9779 nil 9779 9780 (face font-lock-string-face) 9780 9816 (face font-lock-constant-face) 9816 9817 (face font-lock-string-face) 9817 9827 nil 9827 9828 (face font-lock-string-face) 9828 9863 (face font-lock-constant-face) 9863 9864 (face font-lock-string-face) 9864 9874 nil 9874 9875 (face font-lock-string-face) 9875 9910 (face font-lock-constant-face) 9910 9911 (face font-lock-string-face) 9911 9921 nil 9921 9922 (face font-lock-string-face) 9922 9958 (face font-lock-constant-face) 9958 9959 (face font-lock-string-face) 9959 9969 nil 9969 9970 (face font-lock-string-face) 9970 10005 (face font-lock-constant-face) 10005 10006 (face font-lock-string-face) 10006 10016 nil 10016 10017 (face font-lock-string-face) 10017 10050 (face font-lock-constant-face) 10050 10051 (face font-lock-string-face) 10051 10061 nil 10061 10062 (face font-lock-string-face) 10062 10094 (face font-lock-constant-face) 10094 10095 (face font-lock-string-face) 10095 10105 nil 10105 10106 (face font-lock-string-face) 10106 10150 (face font-lock-constant-face) 10150 10151 (face font-lock-string-face) 10151 10161 nil 10161 10162 (face font-lock-string-face) 10162 10198 (face font-lock-constant-face) 10198 10199 (face font-lock-string-face) 10199 10209 nil 10209 10210 (face font-lock-string-face) 10210 10245 (face font-lock-constant-face) 10245 10246 (face font-lock-string-face) 10246 10256 nil 10256 10257 (face font-lock-string-face) 10257 10296 (face font-lock-constant-face) 10296 10297 (face font-lock-string-face) 10297 10307 nil 10307 10308 (face font-lock-string-face) 10308 10346 (face font-lock-constant-face) 10346 10347 (face font-lock-string-face) 10347 10357 nil 10357 10358 (face font-lock-string-face) 10358 10403 (face font-lock-constant-face) 10403 10404 (face font-lock-string-face) 10404 10414 nil 10414 10415 (face font-lock-string-face) 10415 10459 (face font-lock-constant-face) 10459 10460 (face font-lock-string-face) 10460 10470 nil 10470 10471 (face font-lock-string-face) 10471 10487 (face font-lock-constant-face) 10487 10488 (face font-lock-string-face) 10488 10498 nil 10498 10499 (face font-lock-string-face) 10499 10514 (face font-lock-constant-face) 10514 10515 (face font-lock-string-face) 10515 10525 nil 10525 10526 (face font-lock-string-face) 10526 10559 (face font-lock-constant-face) 10559 10560 (face font-lock-string-face) 10560 10570 nil 10570 10571 (face font-lock-string-face) 10571 10603 (face font-lock-constant-face) 10603 10604 (face font-lock-string-face) 10604 10614 nil 10614 10615 (face font-lock-string-face) 10615 10636 (face font-lock-constant-face) 10636 10637 (face font-lock-string-face) 10637 10647 nil 10647 10648 (face font-lock-string-face) 10648 10675 (face font-lock-constant-face) 10675 10676 (face font-lock-string-face) 10676 10686 nil 10686 10687 (face font-lock-string-face) 10687 10713 (face font-lock-constant-face) 10713 10714 (face font-lock-string-face) 10714 10724 nil 10724 10725 (face font-lock-string-face) 10725 10755 (face font-lock-constant-face) 10755 10756 (face font-lock-string-face) 10756 10766 nil 10766 10767 (face font-lock-string-face) 10767 10796 (face font-lock-constant-face) 10796 10797 (face font-lock-string-face) 10797 10807 nil 10807 10808 (face font-lock-string-face) 10808 10845 (face font-lock-constant-face) 10845 10846 (face font-lock-string-face) 10846 10856 nil 10856 10857 (face font-lock-string-face) 10857 10893 (face font-lock-constant-face) 10893 10894 (face font-lock-string-face) 10894 10904 nil 10904 10905 (face font-lock-string-face) 10905 10929 (face font-lock-constant-face) 10929 10930 (face font-lock-string-face) 10930 10940 nil 10940 10941 (face font-lock-string-face) 10941 10964 (face font-lock-constant-face) 10964 10965 (face font-lock-string-face) 10965 10975 nil 10975 10976 (face font-lock-string-face) 10976 10995 (face font-lock-constant-face) 10995 10996 (face font-lock-string-face) 10996 11006 nil 11006 11007 (face font-lock-string-face) 11007 11025 (face font-lock-constant-face) 11025 11026 (face font-lock-string-face) 11026 11036 nil 11036 11037 (face font-lock-string-face) 11037 11063 (face font-lock-constant-face) 11063 11064 (face font-lock-string-face) 11064 11074 nil 11074 11075 (face font-lock-string-face) 11075 11100 (face font-lock-constant-face) 11100 11101 (face font-lock-string-face) 11101 11111 nil 11111 11112 (face font-lock-string-face) 11112 11138 (face font-lock-constant-face) 11138 11139 (face font-lock-string-face) 11139 11149 nil 11149 11150 (face font-lock-string-face) 11150 11175 (face font-lock-constant-face) 11175 11176 (face font-lock-string-face) 11176 11193 nil 11193 11194 (face font-lock-string-face) 11194 11219 (face font-lock-keyword-face) 11219 11220 (face font-lock-string-face) 11220 11232 nil 11232 11233 (face font-lock-string-face) 11233 11245 (face font-lock-keyword-face) 11245 11246 (face font-lock-string-face) 11246 11260 nil 11260 11261 (face font-lock-string-face) 11261 11263 (face font-lock-constant-face) 11263 11264 (face font-lock-string-face) 11264 11292 nil 11292 11293 (face font-lock-string-face) 11293 11303 (face font-lock-keyword-face) 11303 11304 (face font-lock-string-face) 11304 11316 nil 11316 11381 (face font-lock-comment-face) 11381 11389 nil 11389 11439 (face font-lock-comment-face) 11439 11448 nil 11448 11449 (face font-lock-string-face) 11449 11464 (face font-lock-variable-name-face) 11464 11465 (face font-lock-string-face) 11465 11479 nil 11479 11480 (face font-lock-string-face) 11480 11492 (face font-lock-keyword-face) 11492 11493 (face font-lock-string-face) 11493 11509 nil 11509 11510 (face font-lock-string-face) 11510 11549 (face font-lock-function-name-face) 11549 11550 (face font-lock-string-face) 11550 11586 nil 11586 11587 (face font-lock-string-face) 11587 11602 (face font-lock-variable-name-face) 11602 11603 (face font-lock-string-face) 11603 11617 nil 11617 11618 (face font-lock-string-face) 11618 11626 (face font-lock-keyword-face) 11626 11627 (face font-lock-string-face) 11627 11643 nil 11643 11644 (face font-lock-string-face) 11644 11663 (face font-lock-constant-face) 11663 11664 (face font-lock-string-face) 11664 11678 nil 11678 11679 (face font-lock-string-face) 11679 11702 (face font-lock-constant-face) 11702 11703 (face font-lock-string-face) 11703 11717 nil 11717 11718 (face font-lock-string-face) 11718 11740 (face font-lock-constant-face) 11740 11741 (face font-lock-string-face) 11741 11755 nil 11755 11756 (face font-lock-string-face) 11756 11779 (face font-lock-constant-face) 11779 11780 (face font-lock-string-face) 11780 11794 nil 11794 11795 (face font-lock-string-face) 11795 11817 (face font-lock-constant-face) 11817 11818 (face font-lock-string-face) 11818 11832 nil 11832 11833 (face font-lock-string-face) 11833 11861 (face font-lock-constant-face) 11861 11862 (face font-lock-string-face) 11862 11876 nil 11876 11877 (face font-lock-string-face) 11877 11904 (face font-lock-constant-face) 11904 11905 (face font-lock-string-face) 11905 11919 nil 11919 11920 (face font-lock-string-face) 11920 11950 (face font-lock-constant-face) 11950 11951 (face font-lock-string-face) 11951 11965 nil 11965 11966 (face font-lock-string-face) 11966 11995 (face font-lock-constant-face) 11995 11996 (face font-lock-string-face) 11996 12010 nil 12010 12011 (face font-lock-string-face) 12011 12035 (face font-lock-constant-face) 12035 12036 (face font-lock-string-face) 12036 12050 nil 12050 12051 (face font-lock-string-face) 12051 12074 (face font-lock-constant-face) 12074 12075 (face font-lock-string-face) 12075 12089 nil 12089 12090 (face font-lock-string-face) 12090 12120 (face font-lock-constant-face) 12120 12121 (face font-lock-string-face) 12121 12135 nil 12135 12136 (face font-lock-string-face) 12136 12167 (face font-lock-constant-face) 12167 12168 (face font-lock-string-face) 12168 12182 nil 12182 12183 (face font-lock-string-face) 12183 12213 (face font-lock-constant-face) 12213 12214 (face font-lock-string-face) 12214 12228 nil 12228 12229 (face font-lock-string-face) 12229 12254 (face font-lock-constant-face) 12254 12255 (face font-lock-string-face) 12255 12269 nil 12269 12270 (face font-lock-string-face) 12270 12294 (face font-lock-constant-face) 12294 12295 (face font-lock-string-face) 12295 12309 nil 12309 12310 (face font-lock-string-face) 12310 12352 (face font-lock-constant-face) 12352 12353 (face font-lock-string-face) 12353 12367 nil 12367 12368 (face font-lock-string-face) 12368 12409 (face font-lock-constant-face) 12409 12410 (face font-lock-string-face) 12410 12424 nil 12424 12425 (face font-lock-string-face) 12425 12447 (face font-lock-constant-face) 12447 12448 (face font-lock-string-face) 12448 12462 nil 12462 12463 (face font-lock-string-face) 12463 12484 (face font-lock-constant-face) 12484 12485 (face font-lock-string-face) 12485 12499 nil 12499 12500 (face font-lock-string-face) 12500 12531 (face font-lock-constant-face) 12531 12532 (face font-lock-string-face) 12532 12546 nil 12546 12547 (face font-lock-string-face) 12547 12577 (face font-lock-constant-face) 12577 12578 (face font-lock-string-face) 12578 12592 nil 12592 12593 (face font-lock-string-face) 12593 12621 (face font-lock-constant-face) 12621 12622 (face font-lock-string-face) 12622 12636 nil 12636 12637 (face font-lock-string-face) 12637 12664 (face font-lock-constant-face) 12664 12665 (face font-lock-string-face) 12665 12679 nil 12679 12680 (face font-lock-string-face) 12680 12707 (face font-lock-constant-face) 12707 12708 (face font-lock-string-face) 12708 12722 nil 12722 12723 (face font-lock-string-face) 12723 12749 (face font-lock-constant-face) 12749 12750 (face font-lock-string-face) 12750 12764 nil 12764 12765 (face font-lock-string-face) 12765 12791 (face font-lock-constant-face) 12791 12792 (face font-lock-string-face) 12792 12806 nil 12806 12807 (face font-lock-string-face) 12807 12832 (face font-lock-constant-face) 12832 12833 (face font-lock-string-face) 12833 12868 nil 12868 12937 (face font-lock-comment-face) 12937 12945 nil 12945 13016 (face font-lock-comment-face) 13016 13024 nil 13024 13040 (face font-lock-comment-face) 13040 13049 nil 13049 13050 (face font-lock-string-face) 13050 13065 (face font-lock-variable-name-face) 13065 13066 (face font-lock-string-face) 13066 13080 nil 13080 13081 (face font-lock-string-face) 13081 13089 (face font-lock-keyword-face) 13089 13090 (face font-lock-string-face) 13090 13105 nil 13105 13106 (face font-lock-string-face) 13106 13149 (face font-lock-constant-face) 13149 13150 (face font-lock-string-face) 13150 13175 nil 13175 13176 (face font-lock-string-face) 13176 13183 (face font-lock-keyword-face) 13183 13184 (face font-lock-string-face) 13184 13199 nil 13199 13200 (face font-lock-string-face) 13200 13248 (face font-lock-constant-face) 13248 13249 (face font-lock-string-face) 13249 13274 nil 13274 13275 (face font-lock-string-face) 13275 13288 (face font-lock-keyword-face) 13288 13289 (face font-lock-string-face) 13289 13305 nil 13305 13306 (face font-lock-string-face) 13306 13315 (face font-lock-keyword-face) 13315 13316 (face font-lock-string-face) 13316 13334 nil 13334 13335 (face font-lock-string-face) 13335 13345 (face font-lock-constant-face) 13345 13346 (face font-lock-string-face) 13346 13397 nil 13397 13398 (face font-lock-string-face) 13398 13443 (face font-lock-variable-name-face) 13443 13444 (face font-lock-string-face) 13444 13458 nil 13458 13459 (face font-lock-string-face) 13459 13472 (face font-lock-keyword-face) 13472 13473 (face font-lock-string-face) 13473 13489 nil 13489 13490 (face font-lock-string-face) 13490 13499 (face font-lock-keyword-face) 13499 13500 (face font-lock-string-face) 13500 13518 nil 13518 13519 (face font-lock-string-face) 13519 13527 (face font-lock-constant-face) 13527 13528 (face font-lock-string-face) 13528 13579 nil 13579 13580 (face font-lock-string-face) 13580 13593 (face font-lock-variable-name-face) 13593 13594 (face font-lock-string-face) 13594 13608 nil 13608 13609 (face font-lock-string-face) 13609 13617 (face font-lock-keyword-face) 13617 13618 (face font-lock-string-face) 13618 13623 nil 13623 13624 (face font-lock-string-face) 13624 13631 (face font-lock-constant-face) 13631 13632 (face font-lock-string-face) 13632 13634 nil 13634 13635 (face font-lock-string-face) 13635 13641 (face font-lock-constant-face) 13641 13642 (face font-lock-string-face) 13642 13671 nil 13671 13672 (face font-lock-string-face) 13672 13679 (face font-lock-constant-face) 13679 13680 (face font-lock-string-face) 13680 13682 nil 13682 13683 (face font-lock-string-face) 13683 13703 (face font-lock-constant-face) 13703 13704 (face font-lock-string-face) 13704 13720 nil 13720 13721 (face font-lock-string-face) 13721 13734 (face font-lock-keyword-face) 13734 13735 (face font-lock-string-face) 13735 13751 nil 13751 13752 (face font-lock-string-face) 13752 13761 (face font-lock-keyword-face) 13761 13762 (face font-lock-string-face) 13762 13815 nil 13815 13816 (face font-lock-string-face) 13816 13829 (face font-lock-variable-name-face) 13829 13830 (face font-lock-string-face) 13830 13844 nil 13844 13845 (face font-lock-string-face) 13845 13853 (face font-lock-keyword-face) 13853 13854 (face font-lock-string-face) 13854 13870 nil 13870 13871 (face font-lock-string-face) 13871 13909 (face font-lock-constant-face) 13909 13910 (face font-lock-string-face) 13910 13924 nil 13924 13925 (face font-lock-string-face) 13925 13962 (face font-lock-constant-face) 13962 13963 (face font-lock-string-face) 13963 13999 nil 13999 14000 (face font-lock-string-face) 14000 14011 (face font-lock-variable-name-face) 14011 14012 (face font-lock-string-face) 14012 14026 nil 14026 14027 (face font-lock-string-face) 14027 14036 (face font-lock-keyword-face) 14036 14037 (face font-lock-string-face) 14037 14053 nil 14053 14054 (face font-lock-string-face) 14054 14064 (face font-lock-keyword-face) 14064 14065 (face font-lock-string-face) 14065 14084 nil 14084 14085 (face font-lock-string-face) 14085 14096 (face font-lock-variable-name-face) 14096 14097 (face font-lock-string-face) 14097 14117 nil 14117 14129 (face font-lock-string-face) 14129 14131 nil 14131 14169 (face font-lock-string-face) 14169 14176 (face font-lock-variable-name-face) 14176 14182 (face font-lock-string-face) 14182 14193 (face font-lock-variable-name-face) 14193 14196 (face font-lock-string-face) 14196 14233 nil 14233 14245 (face font-lock-string-face) 14245 14247 nil 14247 14259 (face font-lock-string-face) 14259 14316 nil 14316 14317 (face font-lock-string-face) 14317 14327 (face font-lock-keyword-face) 14327 14328 (face font-lock-string-face) 14328 14345 nil 14345 14346 (face font-lock-string-face) 14346 14359 (face font-lock-variable-name-face) 14359 14360 (face font-lock-string-face) 14360 14378 nil 14378 14379 (face font-lock-string-face) 14379 14385 (face font-lock-keyword-face) 14385 14386 (face font-lock-string-face) 14386 14406 nil 14406 14411 (face font-lock-string-face) 14411 14413 (face font-lock-variable-name-face) 14413 14423 (face font-lock-variable-name-face) 14423 14443 (face font-lock-string-face) 14443 14476 nil 14476 14477 (face font-lock-string-face) 14477 14490 (face font-lock-keyword-face) 14490 14491 (face font-lock-string-face) 14491 14511 nil 14511 14512 (face font-lock-string-face) 14512 14521 (face font-lock-keyword-face) 14521 14522 (face font-lock-string-face) 14522 14544 nil 14544 14545 (face font-lock-string-face) 14545 14549 (face font-lock-constant-face) 14549 14551 (face font-lock-variable-name-face) 14551 14561 (face font-lock-variable-name-face) 14561 14578 (face font-lock-constant-face) 14578 14579 (face font-lock-string-face) 14579 14631 nil 14631 14632 (face font-lock-string-face) 14632 14639 (face font-lock-keyword-face) 14639 14640 (face font-lock-string-face) 14640 14660 nil 14660 14661 (face font-lock-string-face) 14661 14669 (face font-lock-preprocessor-face) 14669 14670 (face font-lock-string-face) 14670 14707 nil 14707 14729 (face font-lock-comment-face) 14729 14743 nil 14743 14744 (face font-lock-string-face) 14744 14752 (face font-lock-keyword-face) 14752 14753 (face font-lock-string-face) 14753 14773 nil 14773 14774 (face font-lock-string-face) 14774 14800 (face font-lock-constant-face) 14800 14801 (face font-lock-string-face) 14801 14819 nil 14819 14820 (face font-lock-string-face) 14820 14845 (face font-lock-constant-face) 14845 14846 (face font-lock-string-face) 14846 14915 nil 14915 14916 (face font-lock-string-face) 14916 14929 (face font-lock-variable-name-face) 14929 14930 (face font-lock-string-face) 14930 14944 nil 14944 14945 (face font-lock-string-face) 14945 14955 (face font-lock-keyword-face) 14955 14956 (face font-lock-string-face) 14956 14973 nil 14973 14974 (face font-lock-string-face) 14974 14993 (face font-lock-variable-name-face) 14993 14994 (face font-lock-string-face) 14994 15012 nil 15012 15013 (face font-lock-string-face) 15013 15019 (face font-lock-keyword-face) 15019 15020 (face font-lock-string-face) 15020 15040 nil 15040 15075 (face font-lock-string-face) 15075 15108 nil 15108 15109 (face font-lock-string-face) 15109 15122 (face font-lock-keyword-face) 15122 15123 (face font-lock-string-face) 15123 15143 nil 15143 15144 (face font-lock-string-face) 15144 15153 (face font-lock-keyword-face) 15153 15154 (face font-lock-string-face) 15154 15176 nil 15176 15177 (face font-lock-string-face) 15177 15215 (face font-lock-constant-face) 15215 15216 (face font-lock-string-face) 15216 15268 nil 15268 15269 (face font-lock-string-face) 15269 15276 (face font-lock-keyword-face) 15276 15277 (face font-lock-string-face) 15277 15297 nil 15297 15298 (face font-lock-string-face) 15298 15312 (face font-lock-preprocessor-face) 15312 15313 (face font-lock-string-face) 15313 15350 nil 15350 15378 (face font-lock-comment-face) 15378 15392 nil 15392 15393 (face font-lock-string-face) 15393 15401 (face font-lock-keyword-face) 15401 15402 (face font-lock-string-face) 15402 15422 nil 15422 15423 (face font-lock-string-face) 15423 15450 (face font-lock-constant-face) 15450 15451 (face font-lock-string-face) 15451 15469 nil 15469 15470 (face font-lock-string-face) 15470 15496 (face font-lock-constant-face) 15496 15497 (face font-lock-string-face) 15497 15566 nil 15566 15567 (face font-lock-string-face) 15567 15600 (face font-lock-variable-name-face) 15600 15601 (face font-lock-string-face) 15601 15615 nil 15615 15663 (face font-lock-comment-face) 15663 15673 nil 15673 15674 (face font-lock-string-face) 15674 15682 (face font-lock-keyword-face) 15682 15683 (face font-lock-string-face) 15683 15699 nil 15699 15700 (face font-lock-string-face) 15700 15743 (face font-lock-constant-face) 15743 15744 (face font-lock-string-face) 15744 15758 nil 15758 15759 (face font-lock-string-face) 15759 15801 (face font-lock-constant-face) 15801 15802 (face font-lock-string-face) 15802 15838 nil 15838 15839 (face font-lock-string-face) 15839 15848 (face font-lock-variable-name-face) 15848 15849 (face font-lock-string-face) 15849 15863 nil 15863 15864 (face font-lock-string-face) 15864 15877 (face font-lock-keyword-face) 15877 15878 (face font-lock-string-face) 15878 15894 nil 15894 15895 (face font-lock-string-face) 15895 15904 (face font-lock-keyword-face) 15904 15905 (face font-lock-string-face) 15905 15923 nil 15923 15924 (face font-lock-string-face) 15924 15980 (face font-lock-constant-face) 15980 15981 (face font-lock-string-face) 15981 15997 nil 15997 15998 (face font-lock-string-face) 15998 16057 (face font-lock-constant-face) 16057 16058 (face font-lock-string-face) 16058 16074 nil 16074 16075 (face font-lock-string-face) 16075 16131 (face font-lock-constant-face) 16131 16132 (face font-lock-string-face) 16132 16148 nil 16148 16149 (face font-lock-string-face) 16149 16205 (face font-lock-constant-face) 16205 16206 (face font-lock-string-face) 16206 16222 nil 16222 16223 (face font-lock-string-face) 16223 16275 (face font-lock-constant-face) 16275 16276 (face font-lock-string-face) 16276 16327 nil 16327 16328 (face font-lock-string-face) 16328 16337 (face font-lock-variable-name-face) 16337 16338 (face font-lock-string-face) 16338 16352 nil 16352 16353 (face font-lock-string-face) 16353 16361 (face font-lock-keyword-face) 16361 16362 (face font-lock-string-face) 16362 16378 nil 16378 16379 (face font-lock-string-face) 16379 16406 (face font-lock-constant-face) 16406 16407 (face font-lock-string-face) 16407 16421 nil 16421 16422 (face font-lock-string-face) 16422 16448 (face font-lock-constant-face) 16448 16449 (face font-lock-string-face) 16449 16463 nil 16463 16464 (face font-lock-string-face) 16464 16507 (face font-lock-constant-face) 16507 16508 (face font-lock-string-face) 16508 16522 nil 16522 16523 (face font-lock-string-face) 16523 16565 (face font-lock-constant-face) 16565 16566 (face font-lock-string-face) 16566 16602 nil 16602 16603 (face font-lock-string-face) 16603 16646 (face font-lock-variable-name-face) 16646 16647 (face font-lock-string-face) 16647 16661 nil 16661 16662 (face font-lock-string-face) 16662 16669 (face font-lock-keyword-face) 16669 16670 (face font-lock-string-face) 16670 16686 nil 16686 16687 (face font-lock-string-face) 16687 16697 (face font-lock-constant-face) 16697 16698 (face font-lock-string-face) 16698 16712 nil 16712 16713 (face font-lock-string-face) 16713 16722 (face font-lock-constant-face) 16722 16723 (face font-lock-string-face) 16723 16737 nil 16737 16738 (face font-lock-string-face) 16738 16760 (face font-lock-constant-face) 16760 16761 (face font-lock-string-face) 16761 16775 nil 16775 16776 (face font-lock-string-face) 16776 16797 (face font-lock-constant-face) 16797 16798 (face font-lock-string-face) 16798 16812 nil 16812 16813 (face font-lock-string-face) 16813 16830 (face font-lock-constant-face) 16830 16831 (face font-lock-string-face) 16831 16845 nil 16845 16846 (face font-lock-string-face) 16846 16862 (face font-lock-constant-face) 16862 16863 (face font-lock-string-face) 16863 16877 nil 16877 16878 (face font-lock-string-face) 16878 16889 (face font-lock-constant-face) 16889 16890 (face font-lock-string-face) 16890 16904 nil 16904 16905 (face font-lock-string-face) 16905 16915 (face font-lock-constant-face) 16915 16916 (face font-lock-string-face) 16916 16930 nil 16930 16931 (face font-lock-string-face) 16931 16955 (face font-lock-constant-face) 16955 16956 (face font-lock-string-face) 16956 16970 nil 16970 16971 (face font-lock-string-face) 16971 16994 (face font-lock-constant-face) 16994 16995 (face font-lock-string-face) 16995 17009 nil 17009 17010 (face font-lock-string-face) 17010 17034 (face font-lock-constant-face) 17034 17035 (face font-lock-string-face) 17035 17049 nil 17049 17050 (face font-lock-string-face) 17050 17073 (face font-lock-constant-face) 17073 17074 (face font-lock-string-face) 17074 17088 nil 17088 17089 (face font-lock-string-face) 17089 17114 (face font-lock-constant-face) 17114 17115 (face font-lock-string-face) 17115 17129 nil 17129 17130 (face font-lock-string-face) 17130 17154 (face font-lock-constant-face) 17154 17155 (face font-lock-string-face) 17155 17210 nil 17210 17211 (face font-lock-string-face) 17211 17222 (face font-lock-keyword-face) 17222 17223 (face font-lock-string-face) 17223 17225 nil 17225 17226 (face font-lock-string-face) 17226 17237 (face font-lock-function-name-face) 17237 17238 (face font-lock-string-face) 17238 17246 nil 17246 17247 (face font-lock-string-face) 17247 17251 (face font-lock-keyword-face) 17251 17252 (face font-lock-string-face) 17252 17254 nil 17254 17255 (face font-lock-string-face) 17255 17269 (face font-lock-type-face) 17269 17270 (face font-lock-string-face) 17270 17278 nil 17278 17279 (face font-lock-string-face) 17279 17291 (face font-lock-keyword-face) 17291 17292 (face font-lock-string-face) 17292 17304 nil 17304 17305 (face font-lock-string-face) 17305 17307 (face font-lock-constant-face) 17307 17308 (face font-lock-string-face) 17308 17325 nil 17325 17326 (face font-lock-string-face) 17326 17336 (face font-lock-keyword-face) 17336 17337 (face font-lock-string-face) 17337 17350 nil 17350 17351 (face font-lock-string-face) 17351 17371 (face font-lock-variable-name-face) 17371 17372 (face font-lock-string-face) 17372 17386 nil 17386 17387 (face font-lock-string-face) 17387 17404 (face font-lock-keyword-face) 17404 17405 (face font-lock-string-face) 17405 17423 nil 17423 17424 (face font-lock-string-face) 17424 17442 (face font-lock-variable-name-face) 17442 17443 (face font-lock-string-face) 17443 17461 nil 17461 17462 (face font-lock-string-face) 17462 17469 (face font-lock-keyword-face) 17469 17470 (face font-lock-string-face) 17470 17474 nil 17474 17498 (face font-lock-string-face) 17498 17553 nil 17553 17554 (face font-lock-string-face) 17554 17599 (face font-lock-variable-name-face) 17599 17600 (face font-lock-string-face) 17600 17614 nil 17614 17615 (face font-lock-string-face) 17615 17627 (face font-lock-keyword-face) 17627 17628 (face font-lock-string-face) 17628 17644 nil 17644 17645 (face font-lock-string-face) 17645 17665 (face font-lock-function-name-face) 17665 17666 (face font-lock-string-face) 17666 17703 nil 17703 17704 (face font-lock-string-face) 17704 17724 (face font-lock-variable-name-face) 17724 17725 (face font-lock-string-face) 17725 17739 nil 17739 17740 (face font-lock-string-face) 17740 17752 (face font-lock-keyword-face) 17752 17753 (face font-lock-string-face) 17753 17769 nil 17769 17770 (face font-lock-string-face) 17770 17790 (face font-lock-function-name-face) 17790 17791 (face font-lock-string-face) 17791 17833 nil 17833 17834 (face font-lock-string-face) 17834 17841 (face font-lock-keyword-face) 17841 17842 (face font-lock-string-face) 17842 17854 nil 17854 17855 (face font-lock-string-face) 17855 17874 (face font-lock-constant-face) 17874 17875 (face font-lock-string-face) 17875 17885 nil 17885 17886 (face font-lock-string-face) 17886 17904 (face font-lock-constant-face) 17904 17905 (face font-lock-string-face) 17905 17935 nil 17935 17936 (face font-lock-string-face) 17936 17947 (face font-lock-keyword-face) 17947 17948 (face font-lock-string-face) 17948 17950 nil 17950 17951 (face font-lock-string-face) 17951 17971 (face font-lock-function-name-face) 17971 17972 (face font-lock-string-face) 17972 17980 nil 17980 17981 (face font-lock-string-face) 17981 17985 (face font-lock-keyword-face) 17985 17986 (face font-lock-string-face) 17986 17988 nil 17988 17989 (face font-lock-string-face) 17989 18003 (face font-lock-type-face) 18003 18004 (face font-lock-string-face) 18004 18012 nil 18012 18013 (face font-lock-string-face) 18013 18025 (face font-lock-keyword-face) 18025 18026 (face font-lock-string-face) 18026 18038 nil 18038 18039 (face font-lock-string-face) 18039 18041 (face font-lock-constant-face) 18041 18042 (face font-lock-string-face) 18042 18059 nil 18059 18060 (face font-lock-string-face) 18060 18067 (face font-lock-keyword-face) 18067 18068 (face font-lock-string-face) 18068 18080 nil 18080 18081 (face font-lock-string-face) 18081 18114 (face font-lock-constant-face) 18114 18115 (face font-lock-string-face) 18115 18125 nil 18125 18126 (face font-lock-string-face) 18126 18162 (face font-lock-constant-face) 18162 18163 (face font-lock-string-face) 18163 18173 nil 18173 18174 (face font-lock-string-face) 18174 18212 (face font-lock-constant-face) 18212 18213 (face font-lock-string-face) 18213 18223 nil 18223 18224 (face font-lock-string-face) 18224 18261 (face font-lock-constant-face) 18261 18262 (face font-lock-string-face) 18262 18272 nil 18272 18273 (face font-lock-string-face) 18273 18311 (face font-lock-constant-face) 18311 18312 (face font-lock-string-face) 18312 18322 nil 18322 18323 (face font-lock-string-face) 18323 18356 (face font-lock-constant-face) 18356 18357 (face font-lock-string-face) 18357 18367 nil 18367 18368 (face font-lock-string-face) 18368 18403 (face font-lock-constant-face) 18403 18404 (face font-lock-string-face) 18404 18414 nil 18414 18415 (face font-lock-string-face) 18415 18451 (face font-lock-constant-face) 18451 18452 (face font-lock-string-face) 18452 18462 nil 18462 18463 (face font-lock-string-face) 18463 18499 (face font-lock-constant-face) 18499 18500 (face font-lock-string-face) 18500 18510 nil 18510 18511 (face font-lock-string-face) 18511 18547 (face font-lock-constant-face) 18547 18548 (face font-lock-string-face) 18548 18558 nil 18558 18559 (face font-lock-string-face) 18559 18581 (face font-lock-constant-face) 18581 18582 (face font-lock-string-face) 18582 18592 nil 18592 18593 (face font-lock-string-face) 18593 18618 (face font-lock-constant-face) 18618 18619 (face font-lock-string-face) 18619 18629 nil 18629 18630 (face font-lock-string-face) 18630 18657 (face font-lock-constant-face) 18657 18658 (face font-lock-string-face) 18658 18668 nil 18668 18669 (face font-lock-string-face) 18669 18697 (face font-lock-constant-face) 18697 18698 (face font-lock-string-face) 18698 18708 nil 18708 18709 (face font-lock-string-face) 18709 18750 (face font-lock-constant-face) 18750 18751 (face font-lock-string-face) 18751 18761 nil 18761 18762 (face font-lock-string-face) 18762 18803 (face font-lock-constant-face) 18803 18804 (face font-lock-string-face) 18804 18814 nil 18814 18815 (face font-lock-string-face) 18815 18856 (face font-lock-constant-face) 18856 18857 (face font-lock-string-face) 18857 18867 nil 18867 18868 (face font-lock-string-face) 18868 18902 (face font-lock-constant-face) 18902 18903 (face font-lock-string-face) 18903 18913 nil 18913 18914 (face font-lock-string-face) 18914 18948 (face font-lock-constant-face) 18948 18949 (face font-lock-string-face) 18949 18959 nil 18959 18960 (face font-lock-string-face) 18960 18994 (face font-lock-constant-face) 18994 18995 (face font-lock-string-face) 18995 19005 nil 19005 19006 (face font-lock-string-face) 19006 19035 (face font-lock-constant-face) 19035 19036 (face font-lock-string-face) 19036 19046 nil 19046 19047 (face font-lock-string-face) 19047 19075 (face font-lock-constant-face) 19075 19076 (face font-lock-string-face) 19076 19093 nil 19093 19094 (face font-lock-string-face) 19094 19104 (face font-lock-keyword-face) 19104 19105 (face font-lock-string-face) 19105 19118 nil 19118 19119 (face font-lock-string-face) 19119 19139 (face font-lock-variable-name-face) 19139 19140 (face font-lock-string-face) 19140 19154 nil 19154 19155 (face font-lock-string-face) 19155 19172 (face font-lock-keyword-face) 19172 19173 (face font-lock-string-face) 19173 19191 nil 19191 19192 (face font-lock-string-face) 19192 19210 (face font-lock-variable-name-face) 19210 19211 (face font-lock-string-face) 19211 19229 nil 19229 19230 (face font-lock-string-face) 19230 19237 (face font-lock-keyword-face) 19237 19238 (face font-lock-string-face) 19238 19242 nil 19242 19266 (face font-lock-string-face) 19266 19321 nil 19321 19322 (face font-lock-string-face) 19322 19342 (face font-lock-variable-name-face) 19342 19343 (face font-lock-string-face) 19343 19357 nil 19357 19399 (face font-lock-comment-face) 19399 19409 nil 19409 19410 (face font-lock-string-face) 19410 19417 (face font-lock-keyword-face) 19417 19418 (face font-lock-string-face) 19418 19434 nil 19434 19435 (face font-lock-string-face) 19435 19480 (face font-lock-constant-face) 19480 19481 (face font-lock-string-face) 19481 19495 nil 19495 19496 (face font-lock-string-face) 19496 19535 (face font-lock-constant-face) 19535 19536 (face font-lock-string-face) 19536 19573 nil 19573 19574 (face font-lock-string-face) 19574 19623 (face font-lock-variable-name-face) 19623 19624 (face font-lock-string-face) 19624 19638 nil 19638 19639 (face font-lock-string-face) 19639 19645 (face font-lock-keyword-face) 19645 19646 (face font-lock-string-face) 19646 19662 nil 19662 19670 (face font-lock-string-face) 19670 19707 nil 19707 19708 (face font-lock-string-face) 19708 19719 (face font-lock-variable-name-face) 19719 19720 (face font-lock-string-face) 19720 19734 nil 19734 19735 (face font-lock-string-face) 19735 19749 (face font-lock-keyword-face) 19749 19750 (face font-lock-string-face) 19750 19766 nil 19766 19773 (face font-lock-string-face) 19773 19791 nil 19791 19792 (face font-lock-string-face) 19792 19806 (face font-lock-keyword-face) 19806 19807 (face font-lock-string-face) 19807 19827 nil 19827 19890 (face font-lock-comment-face) 19890 19906 nil 19906 19971 (face font-lock-comment-face) 19971 19987 nil 19987 20032 (face font-lock-comment-face) 20032 20048 nil 20048 20072 (face font-lock-string-face) 20072 20074 nil 20074 20077 (face font-lock-string-face) 20077 20080 nil 20080 20086 (face font-lock-comment-face) 20086 20155 nil 20155 20156 (face 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nil 21325 21326 (face font-lock-string-face) 21326 21334 (face font-lock-keyword-face) 21334 21335 (face font-lock-string-face) 21335 21347 nil 21347 21348 (face font-lock-string-face) 21348 21385 (face font-lock-constant-face) 21385 21386 (face font-lock-string-face) 21386 21416 nil 21416 21417 (face font-lock-string-face) 21417 21428 (face font-lock-keyword-face) 21428 21429 (face font-lock-string-face) 21429 21431 nil 21431 21432 (face font-lock-string-face) 21432 21452 (face font-lock-function-name-face) 21452 21453 (face font-lock-string-face) 21453 21461 nil 21461 21462 (face font-lock-string-face) 21462 21466 (face font-lock-keyword-face) 21466 21467 (face font-lock-string-face) 21467 21469 nil 21469 21470 (face font-lock-string-face) 21470 21484 (face font-lock-type-face) 21484 21485 (face font-lock-string-face) 21485 21493 nil 21493 21494 (face font-lock-string-face) 21494 21506 (face font-lock-keyword-face) 21506 21507 (face font-lock-string-face) 21507 21519 nil 21519 21520 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font-lock-string-face) 26410 26443 (face font-lock-constant-face) 26443 26444 (face font-lock-string-face) 26444 26458 nil 26458 26459 (face font-lock-string-face) 26459 26495 (face font-lock-constant-face) 26495 26496 (face font-lock-string-face) 26496 26532 nil 26532 26533 (face font-lock-string-face) 26533 26546 (face font-lock-variable-name-face) 26546 26547 (face font-lock-string-face) 26547 26561 nil 26561 26562 (face font-lock-string-face) 26562 26572 (face font-lock-keyword-face) 26572 26573 (face font-lock-string-face) 26573 26590 nil 26590 26591 (face font-lock-string-face) 26591 26604 (face font-lock-variable-name-face) 26604 26605 (face font-lock-string-face) 26605 26623 nil 26623 26624 (face font-lock-string-face) 26624 26631 (face font-lock-keyword-face) 26631 26632 (face font-lock-string-face) 26632 26652 nil 26652 26653 (face font-lock-string-face) 26653 26688 (face font-lock-constant-face) 26688 26689 (face font-lock-string-face) 26689 26722 nil 26722 26723 (face font-lock-string-face) 26723 26730 (face font-lock-keyword-face) 26730 26731 (face font-lock-string-face) 26731 26751 nil 26751 26752 (face font-lock-string-face) 26752 26760 (face font-lock-preprocessor-face) 26760 26761 (face font-lock-string-face) 26761 26831 nil 26831 26832 (face font-lock-string-face) 26832 26873 (face font-lock-variable-name-face) 26873 26874 (face font-lock-string-face) 26874 26888 nil 26888 26889 (face font-lock-string-face) 26889 26896 (face font-lock-keyword-face) 26896 26897 (face font-lock-string-face) 26897 26913 nil 26913 26914 (face font-lock-string-face) 26914 26954 (face font-lock-constant-face) 26954 26955 (face font-lock-string-face) 26955 26991 nil 26991 26992 (face font-lock-string-face) 26992 27035 (face font-lock-variable-name-face) 27035 27036 (face font-lock-string-face) 27036 27050 nil 27050 27051 (face font-lock-string-face) 27051 27058 (face font-lock-keyword-face) 27058 27059 (face font-lock-string-face) 27059 27075 nil 27075 27076 (face font-lock-string-face) 27076 27095 (face font-lock-constant-face) 27095 27096 (face font-lock-string-face) 27096 27110 nil 27110 27111 (face font-lock-string-face) 27111 27137 (face font-lock-constant-face) 27137 27138 (face font-lock-string-face) 27138 27152 nil 27152 27153 (face font-lock-string-face) 27153 27186 (face font-lock-constant-face) 27186 27187 (face font-lock-string-face) 27187 27201 nil 27201 27202 (face font-lock-string-face) 27202 27235 (face font-lock-constant-face) 27235 27236 (face font-lock-string-face) 27236 27291 nil 27291 27292 (face font-lock-string-face) 27292 27303 (face font-lock-keyword-face) 27303 27304 (face font-lock-string-face) 27304 27306 nil 27306 27307 (face font-lock-string-face) 27307 27325 (face font-lock-function-name-face) 27325 27326 (face font-lock-string-face) 27326 27334 nil 27334 27335 (face font-lock-string-face) 27335 27339 (face font-lock-keyword-face) 27339 27340 (face font-lock-string-face) 27340 27342 nil 27342 27343 (face font-lock-string-face) 27343 27357 (face font-lock-type-face) 27357 27358 (face font-lock-string-face) 27358 27366 nil 27366 27367 (face font-lock-string-face) 27367 27379 (face font-lock-keyword-face) 27379 27380 (face font-lock-string-face) 27380 27392 nil 27392 27393 (face font-lock-string-face) 27393 27398 (face font-lock-function-name-face) 27398 27399 (face font-lock-string-face) 27399 27409 nil 27409 27410 (face font-lock-string-face) 27410 27431 (face font-lock-function-name-face) 27431 27432 (face font-lock-string-face) 27432 27442 nil 27442 27443 (face font-lock-string-face) 27443 27469 (face font-lock-function-name-face) 27469 27470 (face font-lock-string-face) 27470 27480 nil 27480 27481 (face font-lock-string-face) 27481 27507 (face font-lock-function-name-face) 27507 27508 (face font-lock-string-face) 27508 27525 nil 27525 27526 (face font-lock-string-face) 27526 27533 (face font-lock-keyword-face) 27533 27534 (face font-lock-string-face) 27534 27546 nil 27546 27547 (face font-lock-string-face) 27547 27591 (face font-lock-constant-face) 27591 27592 (face font-lock-string-face) 27592 27602 nil 27602 27603 (face font-lock-string-face) 27603 27646 (face font-lock-constant-face) 27646 27647 (face font-lock-string-face) 27647 27657 nil 27657 27658 (face font-lock-string-face) 27658 27679 (face font-lock-constant-face) 27679 27680 (face font-lock-string-face) 27680 27690 nil 27690 27691 (face font-lock-string-face) 27691 27711 (face font-lock-constant-face) 27711 27712 (face font-lock-string-face) 27712 27722 nil 27722 27723 (face font-lock-string-face) 27723 27752 (face font-lock-constant-face) 27752 27753 (face font-lock-string-face) 27753 27763 nil 27763 27764 (face font-lock-string-face) 27764 27792 (face font-lock-constant-face) 27792 27793 (face font-lock-string-face) 27793 27803 nil 27803 27804 (face font-lock-string-face) 27804 27829 (face font-lock-constant-face) 27829 27830 (face font-lock-string-face) 27830 27840 nil 27840 27841 (face font-lock-string-face) 27841 27865 (face font-lock-constant-face) 27865 27866 (face font-lock-string-face) 27866 27876 nil 27876 27877 (face font-lock-string-face) 27877 27901 (face font-lock-constant-face) 27901 27902 (face font-lock-string-face) 27902 27912 nil 27912 27913 (face font-lock-string-face) 27913 27936 (face font-lock-constant-face) 27936 27937 (face font-lock-string-face) 27937 27947 nil 27947 27948 (face font-lock-string-face) 27948 27968 (face font-lock-constant-face) 27968 27969 (face font-lock-string-face) 27969 27979 nil 27979 27980 (face font-lock-string-face) 27980 27999 (face font-lock-constant-face) 27999 28000 (face font-lock-string-face) 28000 28030 nil 28030 28031 (face font-lock-string-face) 28031 28042 (face font-lock-keyword-face) 28042 28043 (face font-lock-string-face) 28043 28045 nil 28045 28046 (face font-lock-string-face) 28046 28058 (face font-lock-function-name-face) 28058 28059 (face font-lock-string-face) 28059 28067 nil 28067 28068 (face font-lock-string-face) 28068 28072 (face font-lock-keyword-face) 28072 28073 (face font-lock-string-face) 28073 28075 nil 28075 28076 (face font-lock-string-face) 28076 28086 (face font-lock-type-face) 28086 28087 (face font-lock-string-face) 28087 28095 nil 28095 28096 (face font-lock-string-face) 28096 28108 (face font-lock-keyword-face) 28108 28109 (face font-lock-string-face) 28109 28121 nil 28121 28122 (face font-lock-string-face) 28122 28127 (face font-lock-function-name-face) 28127 28128 (face font-lock-string-face) 28128 28138 nil 28138 28139 (face font-lock-string-face) 28139 28150 (face font-lock-function-name-face) 28150 28151 (face font-lock-string-face) 28151 28161 nil 28161 28162 (face font-lock-string-face) 28162 28183 (face font-lock-function-name-face) 28183 28184 (face font-lock-string-face) 28184 28194 nil 28194 28195 (face font-lock-string-face) 28195 28216 (face font-lock-function-name-face) 28216 28217 (face font-lock-string-face) 28217 28234 nil 28234 28235 (face font-lock-string-face) 28235 28242 (face font-lock-keyword-face) 28242 28243 (face font-lock-string-face) 28243 28255 nil 28255 28256 (face font-lock-string-face) 28256 28290 (face font-lock-constant-face) 28290 28291 (face font-lock-string-face) 28291 28321 nil 28321 28322 (face font-lock-string-face) 28322 28333 (face font-lock-keyword-face) 28333 28334 (face font-lock-string-face) 28334 28336 nil 28336 28337 (face font-lock-string-face) 28337 28349 (face font-lock-function-name-face) 28349 28350 (face font-lock-string-face) 28350 28358 nil 28358 28359 (face font-lock-string-face) 28359 28363 (face font-lock-keyword-face) 28363 28364 (face font-lock-string-face) 28364 28366 nil 28366 28367 (face font-lock-string-face) 28367 28377 (face font-lock-type-face) 28377 28378 (face font-lock-string-face) 28378 28386 nil 28386 28387 (face font-lock-string-face) 28387 28394 (face font-lock-keyword-face) 28394 28395 (face font-lock-string-face) 28395 28407 nil 28407 28408 (face font-lock-string-face) 28408 28441 (face font-lock-constant-face) 28441 28442 (face font-lock-string-face) 28442 28471 nil 28471 28472 (face font-lock-string-face) 28472 28483 (face font-lock-keyword-face) 28483 28484 (face font-lock-string-face) 28484 28486 nil 28486 28487 (face font-lock-string-face) 28487 28498 (face font-lock-function-name-face) 28498 28499 (face font-lock-string-face) 28499 28507 nil 28507 28508 (face font-lock-string-face) 28508 28512 (face font-lock-keyword-face) 28512 28513 (face font-lock-string-face) 28513 28515 nil 28515 28516 (face font-lock-string-face) 28516 28526 (face font-lock-type-face) 28526 28527 (face font-lock-string-face) 28527 28535 nil 28535 28536 (face font-lock-string-face) 28536 28548 (face font-lock-keyword-face) 28548 28549 (face font-lock-string-face) 28549 28561 nil 28561 28562 (face font-lock-string-face) 28562 28567 (face font-lock-function-name-face) 28567 28568 (face font-lock-string-face) 28568 28578 nil 28578 28579 (face font-lock-string-face) 28579 28600 (face font-lock-function-name-face) 28600 28601 (face font-lock-string-face) 28601 28618 nil 28618 28619 (face font-lock-string-face) 28619 28626 (face font-lock-keyword-face) 28626 28627 (face font-lock-string-face) 28627 28639 nil 28639 28640 (face font-lock-string-face) 28640 28672 (face font-lock-constant-face) 28672 28673 (face font-lock-string-face) 28673 28698 nil 28698 28699 (face font-lock-string-face) 28699 28709 (face font-lock-keyword-face) 28709 28710 (face font-lock-string-face) 28710 28719 nil 28719 28720 (face font-lock-string-face) 28720 28729 (face font-lock-variable-name-face) 28729 28730 (face font-lock-string-face) 28730 28740 nil 28740 28741 (face font-lock-string-face) 28741 28748 (face font-lock-keyword-face) 28748 28749 (face font-lock-string-face) 28749 28773 nil 28773 28774 (face font-lock-string-face) 28774 28785 (face font-lock-keyword-face) 28785 28786 (face font-lock-string-face) 28786 28788 nil 28788 28789 (face font-lock-string-face) 28789 28799 (face font-lock-function-name-face) 28799 28800 (face font-lock-string-face) 28800 28812 nil 28812 28813 (face font-lock-string-face) 28813 28817 (face font-lock-keyword-face) 28817 28818 (face font-lock-string-face) 28818 28820 nil 28820 28821 (face font-lock-string-face) 28821 28831 (face font-lock-type-face) 28831 28832 (face font-lock-string-face) 28832 28844 nil 28844 28845 (face font-lock-string-face) 28845 28857 (face font-lock-keyword-face) 28857 28858 (face font-lock-string-face) 28858 28874 nil 28874 28875 (face font-lock-string-face) 28875 28880 (face font-lock-function-name-face) 28880 28881 (face font-lock-string-face) 28881 28895 nil 28895 28896 (face font-lock-string-face) 28896 28907 (face font-lock-function-name-face) 28907 28908 (face font-lock-string-face) 28908 28922 nil 28922 28923 (face font-lock-string-face) 28923 28944 (face font-lock-function-name-face) 28944 28945 (face font-lock-string-face) 28945 28959 nil 28959 28960 (face font-lock-string-face) 28960 29043 (face font-lock-function-name-face) 29043 29044 (face font-lock-string-face) 29044 29058 nil 29058 29059 (face font-lock-string-face) 29059 29074 (face font-lock-function-name-face) 29074 29075 (face font-lock-string-face) 29075 29100 nil 29100 29101 (face font-lock-string-face) 29101 29113 (face font-lock-keyword-face) 29113 29114 (face font-lock-string-face) 29114 29130 nil 29130 29131 (face font-lock-string-face) 29131 29133 (face font-lock-constant-face) 29133 29138 (face font-lock-variable-name-face) 29138 29163 (face font-lock-constant-face) 29163 29164 (face font-lock-string-face) 29164 29189 nil 29189 29190 (face font-lock-string-face) 29190 29197 (face font-lock-keyword-face) 29197 29198 (face font-lock-string-face) 29198 29214 nil 29214 29215 (face font-lock-string-face) 29215 29238 (face font-lock-constant-face) 29238 29239 (face font-lock-string-face) 29239 29253 nil 29253 29254 (face font-lock-string-face) 29254 29280 (face font-lock-constant-face) 29280 29281 (face font-lock-string-face) 29281 29295 nil 29295 29296 (face font-lock-string-face) 29296 29321 (face font-lock-constant-face) 29321 29322 (face font-lock-string-face) 29322 29336 nil 29336 29337 (face font-lock-string-face) 29337 29361 (face font-lock-constant-face) 29361 29362 (face font-lock-string-face) 29362 29376 nil 29376 29377 (face font-lock-string-face) 29377 29407 (face font-lock-constant-face) 29407 29408 (face font-lock-string-face) 29408 29422 nil 29422 29423 (face font-lock-string-face) 29423 29453 (face font-lock-constant-face) 29453 29454 (face font-lock-string-face) 29454 29468 nil 29468 29469 (face font-lock-string-face) 29469 29493 (face font-lock-constant-face) 29493 29494 (face font-lock-string-face) 29494 29508 nil 29508 29509 (face font-lock-string-face) 29509 29532 (face font-lock-constant-face) 29532 29533 (face font-lock-string-face) 29533 29547 nil 29547 29548 (face font-lock-string-face) 29548 29575 (face font-lock-constant-face) 29575 29576 (face font-lock-string-face) 29576 29590 nil 29590 29591 (face font-lock-string-face) 29591 29614 (face font-lock-constant-face) 29614 29615 (face font-lock-string-face) 29615 29640 nil 29640 29655 (face font-lock-string-face) 29655 29671 nil 29671 29685 (face font-lock-string-face) 29685 29703 nil 29703 29714 (face font-lock-string-face) 29714 29716 nil 29716 29719 (face font-lock-string-face) 29719 29729 nil 29729 29754 (face font-lock-comment-face) 29754 29792 nil 29792 29793 (face font-lock-string-face) 29793 29800 (face font-lock-keyword-face) 29800 29801 (face font-lock-string-face) 29801 29817 nil 29817 29818 (face font-lock-string-face) 29818 29843 (face font-lock-preprocessor-face) 29843 29844 (face font-lock-string-face) 29844 29892 nil 29892 29893 (face font-lock-string-face) 29893 29929 (face font-lock-variable-name-face) 29929 29930 (face font-lock-string-face) 29930 29940 nil 29940 29941 (face font-lock-string-face) 29941 29948 (face font-lock-keyword-face) 29948 29949 (face font-lock-string-face) 29949 29973 nil 29973 29974 (face font-lock-string-face) 29974 29985 (face font-lock-keyword-face) 29985 29986 (face font-lock-string-face) 29986 29988 nil 29988 29989 (face font-lock-string-face) 29989 30001 (face font-lock-function-name-face) 30001 30002 (face font-lock-string-face) 30002 30014 nil 30014 30015 (face font-lock-string-face) 30015 30019 (face font-lock-keyword-face) 30019 30020 (face font-lock-string-face) 30020 30022 nil 30022 30023 (face font-lock-string-face) 30023 30033 (face font-lock-type-face) 30033 30034 (face font-lock-string-face) 30034 30046 nil 30046 30047 (face font-lock-string-face) 30047 30059 (face font-lock-keyword-face) 30059 30060 (face font-lock-string-face) 30060 30076 nil 30076 30077 (face font-lock-string-face) 30077 30082 (face font-lock-function-name-face) 30082 30083 (face font-lock-string-face) 30083 30097 nil 30097 30098 (face font-lock-string-face) 30098 30109 (face font-lock-function-name-face) 30109 30110 (face font-lock-string-face) 30110 30124 nil 30124 30125 (face font-lock-string-face) 30125 30146 (face font-lock-function-name-face) 30146 30147 (face font-lock-string-face) 30147 30161 nil 30161 30162 (face font-lock-string-face) 30162 30180 (face font-lock-function-name-face) 30180 30181 (face font-lock-string-face) 30181 30206 nil 30206 30207 (face font-lock-string-face) 30207 30214 (face font-lock-keyword-face) 30214 30215 (face font-lock-string-face) 30215 30231 nil 30231 30232 (face font-lock-string-face) 30232 30266 (face font-lock-constant-face) 30266 30267 (face font-lock-string-face) 30267 30281 nil 30281 30282 (face font-lock-string-face) 30282 30321 (face font-lock-constant-face) 30321 30322 (face font-lock-string-face) 30322 30336 nil 30336 30337 (face font-lock-string-face) 30337 30375 (face font-lock-constant-face) 30375 30376 (face font-lock-string-face) 30376 30390 nil 30390 30391 (face font-lock-string-face) 30391 30430 (face font-lock-constant-face) 30430 30431 (face font-lock-string-face) 30431 30445 nil 30445 30446 (face font-lock-string-face) 30446 30484 (face font-lock-constant-face) 30484 30485 (face font-lock-string-face) 30485 30499 nil 30499 30500 (face font-lock-string-face) 30500 30533 (face font-lock-constant-face) 30533 30534 (face font-lock-string-face) 30534 30548 nil 30548 30549 (face font-lock-string-face) 30549 30581 (face font-lock-constant-face) 30581 30582 (face font-lock-string-face) 30582 30596 nil 30596 30597 (face font-lock-string-face) 30597 30626 (face font-lock-constant-face) 30626 30627 (face font-lock-string-face) 30627 30641 nil 30641 30642 (face font-lock-string-face) 30642 30670 (face font-lock-constant-face) 30670 30671 (face font-lock-string-face) 30671 30685 nil 30685 30686 (face font-lock-string-face) 30686 30714 (face font-lock-constant-face) 30714 30715 (face font-lock-string-face) 30715 30729 nil 30729 30730 (face font-lock-string-face) 30730 30757 (face font-lock-constant-face) 30757 30758 (face font-lock-string-face) 30758 30783 nil 30783 30784 (face font-lock-string-face) 30784 30794 (face font-lock-keyword-face) 30794 30795 (face font-lock-string-face) 30795 30812 nil 30812 30813 (face font-lock-string-face) 30813 30834 (face font-lock-variable-name-face) 30834 30835 (face font-lock-string-face) 30835 30853 nil 30853 30854 (face font-lock-string-face) 30854 30866 (face font-lock-keyword-face) 30866 30867 (face font-lock-string-face) 30867 30887 nil 30887 30888 (face font-lock-string-face) 30888 30917 (face font-lock-function-name-face) 30917 30918 (face font-lock-string-face) 30918 30951 nil 30951 30952 (face font-lock-string-face) 30952 30959 (face font-lock-keyword-face) 30959 30960 (face font-lock-string-face) 30960 30980 nil 30980 30981 (face font-lock-string-face) 30981 31015 (face font-lock-constant-face) 31015 31016 (face font-lock-string-face) 31016 31064 nil 31064 31065 (face font-lock-string-face) 31065 31074 (face font-lock-variable-name-face) 31074 31075 (face font-lock-string-face) 31075 31093 nil 31093 31094 (face font-lock-string-face) 31094 31106 (face font-lock-keyword-face) 31106 31107 (face font-lock-string-face) 31107 31127 nil 31127 31128 (face font-lock-string-face) 31128 31175 (face font-lock-function-name-face) 31175 31176 (face font-lock-string-face) 31176 31194 nil 31194 31195 (face font-lock-string-face) 31195 31245 (face font-lock-function-name-face) 31245 31246 (face font-lock-string-face) 31246 31279 nil 31279 31280 (face font-lock-string-face) 31280 31287 (face font-lock-keyword-face) 31287 31288 (face font-lock-string-face) 31288 31308 nil 31308 31309 (face font-lock-string-face) 31309 31341 (face font-lock-constant-face) 31341 31342 (face font-lock-string-face) 31342 31423 nil 31423 31424 (face font-lock-string-face) 31424 31462 (face font-lock-variable-name-face) 31462 31463 (face font-lock-string-face) 31463 31473 nil 31473 31474 (face font-lock-string-face) 31474 31481 (face font-lock-keyword-face) 31481 31482 (face font-lock-string-face) 31482 31506 nil 31506 31507 (face font-lock-string-face) 31507 31518 (face font-lock-keyword-face) 31518 31519 (face font-lock-string-face) 31519 31521 nil 31521 31522 (face font-lock-string-face) 31522 31539 (face font-lock-function-name-face) 31539 31540 (face font-lock-string-face) 31540 31552 nil 31552 31553 (face font-lock-string-face) 31553 31557 (face font-lock-keyword-face) 31557 31558 (face font-lock-string-face) 31558 31560 nil 31560 31561 (face font-lock-string-face) 31561 31571 (face font-lock-type-face) 31571 31572 (face font-lock-string-face) 31572 31584 nil 31584 31585 (face font-lock-string-face) 31585 31597 (face font-lock-keyword-face) 31597 31598 (face font-lock-string-face) 31598 31614 nil 31614 31615 (face font-lock-string-face) 31615 31636 (face font-lock-function-name-face) 31636 31637 (face font-lock-string-face) 31637 31651 nil 31651 31652 (face font-lock-string-face) 31652 31670 (face font-lock-function-name-face) 31670 31671 (face font-lock-string-face) 31671 31696 nil 31696 31697 (face font-lock-string-face) 31697 31706 (face font-lock-keyword-face) 31706 31707 (face font-lock-string-face) 31707 31723 nil 31723 31724 (face font-lock-string-face) 31724 31728 (face font-lock-constant-face) 31728 31729 (face font-lock-string-face) 31729 31743 nil 31743 31744 (face font-lock-string-face) 31744 31748 (face font-lock-constant-face) 31748 31749 (face font-lock-string-face) 31749 31774 nil 31774 31775 (face font-lock-string-face) 31775 31782 (face font-lock-keyword-face) 31782 31783 (face font-lock-string-face) 31783 31799 nil 31799 31800 (face font-lock-string-face) 31800 31844 (face font-lock-constant-face) 31844 31845 (face font-lock-string-face) 31845 31893 nil 31893 31894 (face font-lock-string-face) 31894 31943 (face font-lock-variable-name-face) 31943 31944 (face font-lock-string-face) 31944 31954 nil 31954 31955 (face font-lock-string-face) 31955 31962 (face font-lock-keyword-face) 31962 31963 (face font-lock-string-face) 31963 31987 nil 31987 31988 (face font-lock-string-face) 31988 31999 (face font-lock-keyword-face) 31999 32000 (face font-lock-string-face) 32000 32002 nil 32002 32003 (face font-lock-string-face) 32003 32013 (face font-lock-function-name-face) 32013 32014 (face font-lock-string-face) 32014 32026 nil 32026 32027 (face font-lock-string-face) 32027 32031 (face font-lock-keyword-face) 32031 32032 (face font-lock-string-face) 32032 32034 nil 32034 32035 (face font-lock-string-face) 32035 32045 (face font-lock-type-face) 32045 32046 (face font-lock-string-face) 32046 32058 nil 32058 32059 (face font-lock-string-face) 32059 32071 (face font-lock-keyword-face) 32071 32072 (face font-lock-string-face) 32072 32088 nil 32088 32089 (face font-lock-string-face) 32089 32094 (face font-lock-function-name-face) 32094 32095 (face font-lock-string-face) 32095 32109 nil 32109 32110 (face font-lock-string-face) 32110 32121 (face font-lock-function-name-face) 32121 32122 (face font-lock-string-face) 32122 32136 nil 32136 32137 (face font-lock-string-face) 32137 32158 (face font-lock-function-name-face) 32158 32159 (face font-lock-string-face) 32159 32173 nil 32173 32174 (face font-lock-string-face) 32174 32192 (face font-lock-function-name-face) 32192 32193 (face font-lock-string-face) 32193 32218 nil 32218 32219 (face font-lock-string-face) 32219 32232 (face font-lock-keyword-face) 32232 32233 (face font-lock-string-face) 32233 32249 nil 32249 32250 (face font-lock-string-face) 32250 32259 (face font-lock-keyword-face) 32259 32260 (face font-lock-string-face) 32260 32278 nil 32278 32279 (face font-lock-string-face) 32279 32283 (face font-lock-constant-face) 32283 32284 (face font-lock-string-face) 32284 32300 nil 32300 32301 (face font-lock-string-face) 32301 32306 (face font-lock-constant-face) 32306 32307 (face font-lock-string-face) 32307 32323 nil 32323 32324 (face font-lock-string-face) 32324 32333 (face font-lock-constant-face) 32333 32334 (face font-lock-string-face) 32334 32350 nil 32350 32351 (face font-lock-string-face) 32351 32357 (face font-lock-constant-face) 32357 32358 (face font-lock-string-face) 32358 32398 nil 32398 32399 (face font-lock-string-face) 32399 32406 (face font-lock-keyword-face) 32406 32407 (face font-lock-string-face) 32407 32423 nil 32423 32424 (face font-lock-string-face) 32424 32462 (face font-lock-constant-face) 32462 32463 (face font-lock-string-face) 32463 32477 nil 32477 32478 (face font-lock-string-face) 32478 32515 (face font-lock-constant-face) 32515 32516 (face font-lock-string-face) 32516 32530 nil 32530 32531 (face font-lock-string-face) 32531 32568 (face font-lock-constant-face) 32568 32569 (face font-lock-string-face) 32569 32583 nil 32583 32584 (face font-lock-string-face) 32584 32620 (face font-lock-constant-face) 32620 32621 (face font-lock-string-face) 32621 32635 nil 32635 32636 (face font-lock-string-face) 32636 32666 (face font-lock-constant-face) 32666 32667 (face font-lock-string-face) 32667 32681 nil 32681 32682 (face font-lock-string-face) 32682 32720 (face font-lock-constant-face) 32720 32721 (face font-lock-string-face) 32721 32735 nil 32735 32736 (face font-lock-string-face) 32736 32773 (face font-lock-constant-face) 32773 32774 (face font-lock-string-face) 32774 32822 nil 32822 32823 (face font-lock-string-face) 32823 32838 (face font-lock-variable-name-face) 32838 32839 (face font-lock-string-face) 32839 32849 nil 32849 32850 (face font-lock-string-face) 32850 32857 (face font-lock-keyword-face) 32857 32858 (face font-lock-string-face) 32858 32882 nil 32882 32883 (face font-lock-string-face) 32883 32894 (face font-lock-keyword-face) 32894 32895 (face font-lock-string-face) 32895 32897 nil 32897 32898 (face font-lock-string-face) 32898 32912 (face font-lock-function-name-face) 32912 32913 (face font-lock-string-face) 32913 32925 nil 32925 32926 (face font-lock-string-face) 32926 32930 (face font-lock-keyword-face) 32930 32931 (face font-lock-string-face) 32931 32933 nil 32933 32934 (face font-lock-string-face) 32934 32948 (face font-lock-type-face) 32948 32949 (face font-lock-string-face) 32949 32961 nil 32961 32962 (face font-lock-string-face) 32962 32969 (face font-lock-keyword-face) 32969 32970 (face font-lock-string-face) 32970 32986 nil 32986 32987 (face font-lock-string-face) 32987 33022 (face font-lock-constant-face) 33022 33023 (face font-lock-string-face) 33023 33037 nil 33037 33038 (face font-lock-string-face) 33038 33072 (face font-lock-constant-face) 33072 33073 (face font-lock-string-face) 33073 33098 nil 33098 33099 (face font-lock-string-face) 33099 33111 (face font-lock-keyword-face) 33111 33112 (face font-lock-string-face) 33112 33128 nil 33128 33129 (face font-lock-string-face) 33129 33150 (face font-lock-function-name-face) 33150 33151 (face font-lock-string-face) 33151 33176 nil 33176 33177 (face font-lock-string-face) 33177 33189 (face font-lock-keyword-face) 33189 33190 (face font-lock-string-face) 33190 33206 nil 33206 33207 (face font-lock-string-face) 33207 33209 (face font-lock-constant-face) 33209 33232 (face font-lock-variable-name-face) 33232 33239 (face font-lock-constant-face) 33239 33240 (face font-lock-string-face) 33240 33265 nil 33265 33266 (face font-lock-string-face) 33266 33273 (face font-lock-keyword-face) 33273 33274 (face font-lock-string-face) 33274 33306 nil 33306 33307 (face font-lock-string-face) 33307 33318 (face font-lock-keyword-face) 33318 33319 (face font-lock-string-face) 33319 33321 nil 33321 33322 (face font-lock-string-face) 33322 33342 (face font-lock-function-name-face) 33342 33343 (face font-lock-string-face) 33343 33359 nil 33359 33360 (face font-lock-string-face) 33360 33366 (face font-lock-keyword-face) 33366 33367 (face font-lock-string-face) 33367 33387 nil 33387 33388 (face font-lock-string-face) 33388 33434 (face font-lock-constant-face) 33434 33435 (face font-lock-string-face) 33435 33453 nil 33453 33454 (face font-lock-string-face) 33454 33519 (face font-lock-constant-face) 33519 33520 (face font-lock-string-face) 33520 33553 nil 33553 33554 (face font-lock-string-face) 33554 33561 (face font-lock-keyword-face) 33561 33562 (face font-lock-string-face) 33562 33582 nil 33582 33583 (face font-lock-string-face) 33583 33585 (face font-lock-constant-face) 33585 33608 (face font-lock-variable-name-face) 33608 33647 (face font-lock-constant-face) 33647 33648 (face font-lock-string-face) 33648 33681 nil 33681 33682 (face font-lock-string-face) 33682 33688 (face font-lock-keyword-face) 33688 33689 (face font-lock-string-face) 33689 33709 nil 33709 33710 (face font-lock-string-face) 33710 33716 (face font-lock-constant-face) 33716 33717 (face font-lock-string-face) 33717 33735 nil 33735 33736 (face font-lock-string-face) 33736 33738 (face font-lock-constant-face) 33738 33743 (face font-lock-variable-name-face) 33743 33788 (face font-lock-constant-face) 33788 33789 (face font-lock-string-face) 33789 33807 nil 33807 33808 (face font-lock-string-face) 33808 33810 (face font-lock-constant-face) 33810 33811 (face font-lock-string-face) 33811 33829 nil 33829 33830 (face font-lock-string-face) 33830 33833 (face font-lock-constant-face) 33833 33840 (face font-lock-variable-name-face) 33840 33841 (face font-lock-constant-face) 33841 33842 (face font-lock-string-face) 33842 33860 nil 33860 33861 (face font-lock-string-face) 33861 33864 (face font-lock-constant-face) 33864 33872 (face font-lock-variable-name-face) 33872 33873 (face font-lock-constant-face) 33873 33874 (face font-lock-string-face) 33874 33952 nil 33952 33953 (face font-lock-string-face) 33953 33964 (face font-lock-keyword-face) 33964 33965 (face font-lock-string-face) 33965 33967 nil 33967 33968 (face font-lock-string-face) 33968 33978 (face font-lock-function-name-face) 33978 33979 (face font-lock-string-face) 33979 33991 nil 33991 33992 (face font-lock-string-face) 33992 33996 (face font-lock-keyword-face) 33996 33997 (face font-lock-string-face) 33997 33999 nil 33999 34000 (face font-lock-string-face) 34000 34004 (face font-lock-type-face) 34004 34005 (face font-lock-string-face) 34005 34017 nil 34017 34018 (face font-lock-string-face) 34018 34030 (face font-lock-keyword-face) 34030 34031 (face font-lock-string-face) 34031 34035 nil 34035 34036 (face font-lock-string-face) 34036 34062 (face font-lock-function-name-face) 34062 34063 (face font-lock-string-face) 34063 34077 nil 34077 34078 (face font-lock-string-face) 34078 34087 (face font-lock-keyword-face) 34087 34088 (face font-lock-string-face) 34088 34104 nil 34104 34105 (face font-lock-string-face) 34105 34117 (face font-lock-variable-name-face) 34117 34118 (face font-lock-string-face) 34118 34120 nil 34120 34121 (face font-lock-string-face) 34121 34126 (face font-lock-variable-name-face) 34126 34127 (face font-lock-string-face) 34127 34141 nil 34141 34142 (face font-lock-string-face) 34142 34153 (face font-lock-variable-name-face) 34153 34154 (face font-lock-string-face) 34154 34156 nil 34156 34157 (face font-lock-string-face) 34157 34174 (face font-lock-variable-name-face) 34174 34175 (face font-lock-string-face) 34175 34200 nil 34200 34201 (face font-lock-string-face) 34201 34209 (face font-lock-keyword-face) 34209 34210 (face font-lock-string-face) 34210 34214 nil 34214 34215 (face font-lock-string-face) 34215 34233 (face font-lock-constant-face) 34233 34234 (face font-lock-string-face) 34234 34268 nil 34268 34287 (face font-lock-comment-face) 34287 34293 nil 34293 34365 (face font-lock-comment-face) 34365 34371 nil 34371 34372 (face font-lock-string-face) 34372 34379 (face font-lock-keyword-face) 34379 34380 (face font-lock-string-face) 34380 34404 nil 34404 34405 (face font-lock-string-face) 34405 34416 (face font-lock-keyword-face) 34416 34417 (face font-lock-string-face) 34417 34419 nil 34419 34420 (face font-lock-string-face) 34420 34436 (face font-lock-function-name-face) 34436 34437 (face font-lock-string-face) 34437 34449 nil 34449 34450 (face font-lock-string-face) 34450 34454 (face font-lock-keyword-face) 34454 34455 (face font-lock-string-face) 34455 34457 nil 34457 34458 (face font-lock-string-face) 34458 34468 (face font-lock-type-face) 34468 34469 (face font-lock-string-face) 34469 34481 nil 34481 34482 (face font-lock-string-face) 34482 34494 (face font-lock-keyword-face) 34494 34495 (face font-lock-string-face) 34495 34511 nil 34511 34512 (face font-lock-string-face) 34512 34517 (face font-lock-function-name-face) 34517 34518 (face font-lock-string-face) 34518 34532 nil 34532 34533 (face font-lock-string-face) 34533 34551 (face font-lock-function-name-face) 34551 34552 (face font-lock-string-face) 34552 34566 nil 34566 34567 (face font-lock-string-face) 34567 34588 (face font-lock-function-name-face) 34588 34589 (face font-lock-string-face) 34589 34603 nil 34603 34604 (face font-lock-string-face) 34604 34630 (face font-lock-function-name-face) 34630 34631 (face font-lock-string-face) 34631 34645 nil 34645 34646 (face font-lock-string-face) 34646 34680 (face font-lock-function-name-face) 34680 34681 (face font-lock-string-face) 34681 34695 nil 34695 34696 (face font-lock-string-face) 34696 34730 (face font-lock-function-name-face) 34730 34731 (face font-lock-string-face) 34731 34745 nil 34745 34746 (face font-lock-string-face) 34746 34772 (face font-lock-function-name-face) 34772 34773 (face font-lock-string-face) 34773 34787 nil 34787 34788 (face font-lock-string-face) 34788 34827 (face font-lock-function-name-face) 34827 34828 (face font-lock-string-face) 34828 34853 nil 34853 34854 (face font-lock-string-face) 34854 34861 (face font-lock-keyword-face) 34861 34862 (face font-lock-string-face) 34862 34878 nil 34878 34879 (face font-lock-string-face) 34879 34904 (face font-lock-constant-face) 34904 34905 (face font-lock-string-face) 34905 34930 nil 34930 34931 (face font-lock-string-face) 34931 34941 (face font-lock-keyword-face) 34941 34942 (face font-lock-string-face) 34942 34959 nil 34959 34960 (face font-lock-string-face) 34960 34981 (face font-lock-variable-name-face) 34981 34982 (face font-lock-string-face) 34982 35000 nil 35000 35001 (face font-lock-string-face) 35001 35013 (face font-lock-keyword-face) 35013 35014 (face font-lock-string-face) 35014 35034 nil 35034 35077 (face font-lock-comment-face) 35077 35093 nil 35093 35123 (face font-lock-comment-face) 35123 35139 nil 35139 35164 (face font-lock-comment-face) 35164 35180 nil 35180 35194 (face font-lock-comment-face) 35194 35210 nil 35210 35211 (face font-lock-string-face) 35211 35240 (face font-lock-function-name-face) 35240 35241 (face font-lock-string-face) 35241 35274 nil 35274 35275 (face font-lock-string-face) 35275 35285 (face font-lock-keyword-face) 35285 35286 (face font-lock-string-face) 35286 35307 nil 35307 35308 (face font-lock-string-face) 35308 35329 (face font-lock-variable-name-face) 35329 35330 (face font-lock-string-face) 35330 35352 nil 35352 35353 (face font-lock-string-face) 35353 35365 (face font-lock-keyword-face) 35365 35366 (face font-lock-string-face) 35366 35390 nil 35390 35391 (face font-lock-string-face) 35391 35432 (face font-lock-function-name-face) 35432 35433 (face font-lock-string-face) 35433 35553 nil 35553 35554 (face font-lock-string-face) 35554 35565 (face font-lock-keyword-face) 35565 35566 (face font-lock-string-face) 35566 35568 nil 35568 35569 (face font-lock-string-face) 35569 35592 (face font-lock-function-name-face) 35592 35593 (face font-lock-string-face) 35593 35605 nil 35605 35606 (face font-lock-string-face) 35606 35610 (face font-lock-keyword-face) 35610 35611 (face font-lock-string-face) 35611 35613 nil 35613 35614 (face font-lock-string-face) 35614 35624 (face font-lock-type-face) 35624 35625 (face font-lock-string-face) 35625 35637 nil 35637 35638 (face font-lock-string-face) 35638 35650 (face font-lock-keyword-face) 35650 35651 (face font-lock-string-face) 35651 35667 nil 35667 35668 (face font-lock-string-face) 35668 35673 (face font-lock-function-name-face) 35673 35674 (face font-lock-string-face) 35674 35688 nil 35688 35689 (face font-lock-string-face) 35689 35707 (face font-lock-function-name-face) 35707 35708 (face font-lock-string-face) 35708 35722 nil 35722 35723 (face font-lock-string-face) 35723 35757 (face font-lock-function-name-face) 35757 35758 (face font-lock-string-face) 35758 35772 nil 35772 35773 (face font-lock-string-face) 35773 35799 (face font-lock-function-name-face) 35799 35800 (face font-lock-string-face) 35800 35814 nil 35814 35815 (face font-lock-string-face) 35815 35841 (face font-lock-function-name-face) 35841 35842 (face font-lock-string-face) 35842 35856 nil 35856 35857 (face font-lock-string-face) 35857 35896 (face font-lock-function-name-face) 35896 35897 (face font-lock-string-face) 35897 35922 nil 35922 35923 (face font-lock-string-face) 35923 35930 (face font-lock-keyword-face) 35930 35931 (face font-lock-string-face) 35931 35947 nil 35947 35948 (face font-lock-string-face) 35948 35970 (face font-lock-constant-face) 35970 35971 (face font-lock-string-face) 35971 35985 nil 35985 35986 (face font-lock-string-face) 35986 36011 (face font-lock-constant-face) 36011 36012 (face font-lock-string-face) 36012 36026 nil 36026 36027 (face font-lock-string-face) 36027 36060 (face font-lock-constant-face) 36060 36061 (face font-lock-string-face) 36061 36075 nil 36075 36076 (face font-lock-string-face) 36076 36117 (face font-lock-constant-face) 36117 36118 (face font-lock-string-face) 36118 36143 nil 36143 36144 (face font-lock-string-face) 36144 36154 (face font-lock-keyword-face) 36154 36155 (face font-lock-string-face) 36155 36172 nil 36172 36173 (face font-lock-string-face) 36173 36198 (face font-lock-variable-name-face) 36198 36199 (face font-lock-string-face) 36199 36217 nil 36217 36218 (face font-lock-string-face) 36218 36228 (face font-lock-keyword-face) 36228 36229 (face font-lock-string-face) 36229 36250 nil 36250 36251 (face font-lock-string-face) 36251 36272 (face font-lock-variable-name-face) 36272 36273 (face font-lock-string-face) 36273 36295 nil 36295 36296 (face font-lock-string-face) 36296 36308 (face font-lock-keyword-face) 36308 36309 (face font-lock-string-face) 36309 36333 nil 36333 36334 (face font-lock-string-face) 36334 36375 (face font-lock-function-name-face) 36375 36376 (face font-lock-string-face) 36376 36496 nil 36496 36497 (face font-lock-string-face) 36497 36508 (face font-lock-keyword-face) 36508 36509 (face font-lock-string-face) 36509 36511 nil 36511 36512 (face font-lock-string-face) 36512 36524 (face font-lock-function-name-face) 36524 36525 (face font-lock-string-face) 36525 36537 nil 36537 36538 (face font-lock-string-face) 36538 36542 (face font-lock-keyword-face) 36542 36543 (face font-lock-string-face) 36543 36545 nil 36545 36546 (face font-lock-string-face) 36546 36556 (face font-lock-type-face) 36556 36557 (face font-lock-string-face) 36557 36569 nil 36569 36570 (face font-lock-string-face) 36570 36582 (face font-lock-keyword-face) 36582 36583 (face font-lock-string-face) 36583 36599 nil 36599 36600 (face font-lock-string-face) 36600 36605 (face font-lock-function-name-face) 36605 36606 (face font-lock-string-face) 36606 36620 nil 36620 36621 (face font-lock-string-face) 36621 36642 (face font-lock-function-name-face) 36642 36643 (face font-lock-string-face) 36643 36657 nil 36657 36658 (face font-lock-string-face) 36658 36697 (face font-lock-function-name-face) 36697 36698 (face font-lock-string-face) 36698 36723 nil 36723 36724 (face font-lock-string-face) 36724 36731 (face font-lock-keyword-face) 36731 36732 (face font-lock-string-face) 36732 36748 nil 36748 36749 (face font-lock-string-face) 36749 36782 (face font-lock-constant-face) 36782 36783 (face font-lock-string-face) 36783 36829 nil 36829 36830 (face font-lock-string-face) 36830 36841 (face font-lock-keyword-face) 36841 36842 (face font-lock-string-face) 36842 36844 nil 36844 36845 (face font-lock-string-face) 36845 36856 (face font-lock-function-name-face) 36856 36857 (face font-lock-string-face) 36857 36869 nil 36869 36870 (face font-lock-string-face) 36870 36874 (face font-lock-keyword-face) 36874 36875 (face font-lock-string-face) 36875 36877 nil 36877 36878 (face font-lock-string-face) 36878 36888 (face font-lock-type-face) 36888 36889 (face font-lock-string-face) 36889 36901 nil 36901 36902 (face font-lock-string-face) 36902 36914 (face font-lock-keyword-face) 36914 36915 (face font-lock-string-face) 36915 36931 nil 36931 36932 (face font-lock-string-face) 36932 36937 (face font-lock-function-name-face) 36937 36938 (face font-lock-string-face) 36938 36952 nil 36952 36953 (face font-lock-string-face) 36953 36974 (face font-lock-function-name-face) 36974 36975 (face font-lock-string-face) 36975 36989 nil 36989 36990 (face font-lock-string-face) 36990 37029 (face font-lock-function-name-face) 37029 37030 (face font-lock-string-face) 37030 37055 nil 37055 37056 (face font-lock-string-face) 37056 37063 (face font-lock-keyword-face) 37063 37064 (face font-lock-string-face) 37064 37080 nil 37080 37081 (face font-lock-string-face) 37081 37113 (face font-lock-constant-face) 37113 37114 (face font-lock-string-face) 37114 37163 nil)
diff --git a/server/node_modules/node-gyp/gyp/tools/graphviz.py b/server/node_modules/node-gyp/gyp/tools/graphviz.py
new file mode 100755
index 0000000..f19426b
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/graphviz.py
@@ -0,0 +1,102 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2011 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Using the JSON dumped by the dump-dependency-json generator,
+generate input suitable for graphviz to render a dependency graph of
+targets."""
+
+
+import collections
+import json
+import sys
+
+
+def ParseTarget(target):
+    target, _, suffix = target.partition("#")
+    filename, _, target = target.partition(":")
+    return filename, target, suffix
+
+
+def LoadEdges(filename, targets):
+    """Load the edges map from the dump file, and filter it to only
+  show targets in |targets| and their depedendents."""
+
+    file = open("dump.json")
+    edges = json.load(file)
+    file.close()
+
+    # Copy out only the edges we're interested in from the full edge list.
+    target_edges = {}
+    to_visit = targets[:]
+    while to_visit:
+        src = to_visit.pop()
+        if src in target_edges:
+            continue
+        target_edges[src] = edges[src]
+        to_visit.extend(edges[src])
+
+    return target_edges
+
+
+def WriteGraph(edges):
+    """Print a graphviz graph to stdout.
+  |edges| is a map of target to a list of other targets it depends on."""
+
+    # Bucket targets by file.
+    files = collections.defaultdict(list)
+    for src, dst in edges.items():
+        build_file, target_name, toolset = ParseTarget(src)
+        files[build_file].append(src)
+
+    print("digraph D {")
+    print("  fontsize=8")  # Used by subgraphs.
+    print("  node [fontsize=8]")
+
+    # Output nodes by file.  We must first write out each node within
+    # its file grouping before writing out any edges that may refer
+    # to those nodes.
+    for filename, targets in files.items():
+        if len(targets) == 1:
+            # If there's only one node for this file, simplify
+            # the display by making it a box without an internal node.
+            target = targets[0]
+            build_file, target_name, toolset = ParseTarget(target)
+            print(
+                f'  "{target}" [shape=box, label="{filename}\\n{target_name}"]'
+            )
+        else:
+            # Group multiple nodes together in a subgraph.
+            print('  subgraph "cluster_%s" {' % filename)
+            print('    label = "%s"' % filename)
+            for target in targets:
+                build_file, target_name, toolset = ParseTarget(target)
+                print(f'    "{target}" [label="{target_name}"]')
+            print("  }")
+
+    # Now that we've placed all the nodes within subgraphs, output all
+    # the edges between nodes.
+    for src, dsts in edges.items():
+        for dst in dsts:
+            print(f'  "{src}" -> "{dst}"')
+
+    print("}")
+
+
+def main():
+    if len(sys.argv) < 2:
+        print(__doc__, file=sys.stderr)
+        print(file=sys.stderr)
+        print("usage: %s target1 target2..." % (sys.argv[0]), file=sys.stderr)
+        return 1
+
+    edges = LoadEdges("dump.json", sys.argv[1:])
+
+    WriteGraph(edges)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/server/node_modules/node-gyp/gyp/tools/pretty_gyp.py b/server/node_modules/node-gyp/gyp/tools/pretty_gyp.py
new file mode 100755
index 0000000..4ffa444
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/pretty_gyp.py
@@ -0,0 +1,156 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Pretty-prints the contents of a GYP file."""
+
+
+import sys
+import re
+
+
+# Regex to remove comments when we're counting braces.
+COMMENT_RE = re.compile(r"\s*#.*")
+
+# Regex to remove quoted strings when we're counting braces.
+# It takes into account quoted quotes, and makes sure that the quotes match.
+# NOTE: It does not handle quotes that span more than one line, or
+# cases where an escaped quote is preceded by an escaped backslash.
+QUOTE_RE_STR = r'(?P<q>[\'"])(.*?)(?<![^\\][\\])(?P=q)'
+QUOTE_RE = re.compile(QUOTE_RE_STR)
+
+
+def comment_replace(matchobj):
+    return matchobj.group(1) + matchobj.group(2) + "#" * len(matchobj.group(3))
+
+
+def mask_comments(input):
+    """Mask the quoted strings so we skip braces inside quoted strings."""
+    search_re = re.compile(r"(.*?)(#)(.*)")
+    return [search_re.sub(comment_replace, line) for line in input]
+
+
+def quote_replace(matchobj):
+    return "{}{}{}{}".format(
+        matchobj.group(1),
+        matchobj.group(2),
+        "x" * len(matchobj.group(3)),
+        matchobj.group(2),
+    )
+
+
+def mask_quotes(input):
+    """Mask the quoted strings so we skip braces inside quoted strings."""
+    search_re = re.compile(r"(.*?)" + QUOTE_RE_STR)
+    return [search_re.sub(quote_replace, line) for line in input]
+
+
+def do_split(input, masked_input, search_re):
+    output = []
+    mask_output = []
+    for (line, masked_line) in zip(input, masked_input):
+        m = search_re.match(masked_line)
+        while m:
+            split = len(m.group(1))
+            line = line[:split] + r"\n" + line[split:]
+            masked_line = masked_line[:split] + r"\n" + masked_line[split:]
+            m = search_re.match(masked_line)
+        output.extend(line.split(r"\n"))
+        mask_output.extend(masked_line.split(r"\n"))
+    return (output, mask_output)
+
+
+def split_double_braces(input):
+    """Masks out the quotes and comments, and then splits appropriate
+  lines (lines that matche the double_*_brace re's above) before
+  indenting them below.
+
+  These are used to split lines which have multiple braces on them, so
+  that the indentation looks prettier when all laid out (e.g. closing
+  braces make a nice diagonal line).
+  """
+    double_open_brace_re = re.compile(r"(.*?[\[\{$,])(\s*)([\[\{\(])")
+    double_close_brace_re = re.compile(r"(.*?[\]\}$],?)(\s*)([\]\}\)])")
+
+    masked_input = mask_quotes(input)
+    masked_input = mask_comments(masked_input)
+
+    (output, mask_output) = do_split(input, masked_input, double_open_brace_re)
+    (output, mask_output) = do_split(output, mask_output, double_close_brace_re)
+
+    return output
+
+
+def count_braces(line):
+    """keeps track of the number of braces on a given line and returns the result.
+
+  It starts at zero and subtracts for closed braces, and adds for open braces.
+  """
+    open_braces = ["[", "(", "{"]
+    close_braces = ["]", ")", "}"]
+    closing_prefix_re = re.compile(r"(.*?[^\s\]\}\)]+.*?)([\]\}\)],?)\s*$")
+    cnt = 0
+    stripline = COMMENT_RE.sub(r"", line)
+    stripline = QUOTE_RE.sub(r"''", stripline)
+    for char in stripline:
+        for brace in open_braces:
+            if char == brace:
+                cnt += 1
+        for brace in close_braces:
+            if char == brace:
+                cnt -= 1
+
+    after = False
+    if cnt > 0:
+        after = True
+
+    # This catches the special case of a closing brace having something
+    # other than just whitespace ahead of it -- we don't want to
+    # unindent that until after this line is printed so it stays with
+    # the previous indentation level.
+    if cnt < 0 and closing_prefix_re.match(stripline):
+        after = True
+    return (cnt, after)
+
+
+def prettyprint_input(lines):
+    """Does the main work of indenting the input based on the brace counts."""
+    indent = 0
+    basic_offset = 2
+    for line in lines:
+        if COMMENT_RE.match(line):
+            print(line)
+        else:
+            line = line.strip("\r\n\t ")  # Otherwise doesn't strip \r on Unix.
+            if len(line) > 0:
+                (brace_diff, after) = count_braces(line)
+                if brace_diff != 0:
+                    if after:
+                        print(" " * (basic_offset * indent) + line)
+                        indent += brace_diff
+                    else:
+                        indent += brace_diff
+                        print(" " * (basic_offset * indent) + line)
+                else:
+                    print(" " * (basic_offset * indent) + line)
+            else:
+                print("")
+
+
+def main():
+    if len(sys.argv) > 1:
+        data = open(sys.argv[1]).read().splitlines()
+    else:
+        data = sys.stdin.read().splitlines()
+    # Split up the double braces.
+    lines = split_double_braces(data)
+
+    # Indent and print the output.
+    prettyprint_input(lines)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/server/node_modules/node-gyp/gyp/tools/pretty_sln.py b/server/node_modules/node-gyp/gyp/tools/pretty_sln.py
new file mode 100755
index 0000000..6ca0cd1
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/pretty_sln.py
@@ -0,0 +1,181 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Prints the information in a sln file in a diffable way.
+
+   It first outputs each projects in alphabetical order with their
+   dependencies.
+
+   Then it outputs a possible build order.
+"""
+
+
+import os
+import re
+import sys
+import pretty_vcproj
+
+__author__ = "nsylvain (Nicolas Sylvain)"
+
+
+def BuildProject(project, built, projects, deps):
+    # if all dependencies are done, we can build it, otherwise we try to build the
+    # dependency.
+    # This is not infinite-recursion proof.
+    for dep in deps[project]:
+        if dep not in built:
+            BuildProject(dep, built, projects, deps)
+    print(project)
+    built.append(project)
+
+
+def ParseSolution(solution_file):
+    # All projects, their clsid and paths.
+    projects = dict()
+
+    # A list of dependencies associated with a project.
+    dependencies = dict()
+
+    # Regular expressions that matches the SLN format.
+    # The first line of a project definition.
+    begin_project = re.compile(
+        r'^Project$"{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942'
+        r'}"$ = "(.*)", "(.*)", "(.*)"$'
+    )
+    # The last line of a project definition.
+    end_project = re.compile("^EndProject$")
+    # The first line of a dependency list.
+    begin_dep = re.compile(r"ProjectSection$ProjectDependencies$ = postProject$")
+    # The last line of a dependency list.
+    end_dep = re.compile("EndProjectSection$")
+    # A line describing a dependency.
+    dep_line = re.compile(" *({.*}) = ({.*})$")
+
+    in_deps = False
+    solution = open(solution_file)
+    for line in solution:
+        results = begin_project.search(line)
+        if results:
+            # Hack to remove icu because the diff is too different.
+            if results.group(1).find("icu") != -1:
+                continue
+            # We remove "_gyp" from the names because it helps to diff them.
+            current_project = results.group(1).replace("_gyp", "")
+            projects[current_project] = [
+                results.group(2).replace("_gyp", ""),
+                results.group(3),
+                results.group(2),
+            ]
+            dependencies[current_project] = []
+            continue
+
+        results = end_project.search(line)
+        if results:
+            current_project = None
+            continue
+
+        results = begin_dep.search(line)
+        if results:
+            in_deps = True
+            continue
+
+        results = end_dep.search(line)
+        if results:
+            in_deps = False
+            continue
+
+        results = dep_line.search(line)
+        if results and in_deps and current_project:
+            dependencies[current_project].append(results.group(1))
+            continue
+
+    # Change all dependencies clsid to name instead.
+    for project in dependencies:
+        # For each dependencies in this project
+        new_dep_array = []
+        for dep in dependencies[project]:
+            # Look for the project name matching this cldis
+            for project_info in projects:
+                if projects[project_info][1] == dep:
+                    new_dep_array.append(project_info)
+        dependencies[project] = sorted(new_dep_array)
+
+    return (projects, dependencies)
+
+
+def PrintDependencies(projects, deps):
+    print("---------------------------------------")
+    print("Dependencies for all projects")
+    print("---------------------------------------")
+    print("--                                   --")
+
+    for (project, dep_list) in sorted(deps.items()):
+        print("Project : %s" % project)
+        print("Path : %s" % projects[project][0])
+        if dep_list:
+            for dep in dep_list:
+                print("  - %s" % dep)
+        print("")
+
+    print("--                                   --")
+
+
+def PrintBuildOrder(projects, deps):
+    print("---------------------------------------")
+    print("Build order                            ")
+    print("---------------------------------------")
+    print("--                                   --")
+
+    built = []
+    for (project, _) in sorted(deps.items()):
+        if project not in built:
+            BuildProject(project, built, projects, deps)
+
+    print("--                                   --")
+
+
+def PrintVCProj(projects):
+
+    for project in projects:
+        print("-------------------------------------")
+        print("-------------------------------------")
+        print(project)
+        print(project)
+        print(project)
+        print("-------------------------------------")
+        print("-------------------------------------")
+
+        project_path = os.path.abspath(
+            os.path.join(os.path.dirname(sys.argv[1]), projects[project][2])
+        )
+
+        pretty = pretty_vcproj
+        argv = [
+            "",
+            project_path,
+            "$(SolutionDir)=%s\\" % os.path.dirname(sys.argv[1]),
+        ]
+        argv.extend(sys.argv[3:])
+        pretty.main(argv)
+
+
+def main():
+    # check if we have exactly 1 parameter.
+    if len(sys.argv) < 2:
+        print('Usage: %s "c:\\path\\to\\project.sln"' % sys.argv[0])
+        return 1
+
+    (projects, deps) = ParseSolution(sys.argv[1])
+    PrintDependencies(projects, deps)
+    PrintBuildOrder(projects, deps)
+
+    if "--recursive" in sys.argv:
+        PrintVCProj(projects)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/server/node_modules/node-gyp/gyp/tools/pretty_vcproj.py b/server/node_modules/node-gyp/gyp/tools/pretty_vcproj.py
new file mode 100755
index 0000000..00d32de
--- /dev/null
+++ b/server/node_modules/node-gyp/gyp/tools/pretty_vcproj.py
@@ -0,0 +1,339 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2012 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Make the format of a vcproj really pretty.
+
+   This script normalize and sort an xml. It also fetches all the properties
+   inside linked vsprops and include them explicitly in the vcproj.
+
+   It outputs the resulting xml to stdout.
+"""
+
+
+import os
+import sys
+
+from xml.dom.minidom import parse
+from xml.dom.minidom import Node
+
+__author__ = "nsylvain (Nicolas Sylvain)"
+ARGUMENTS = None
+REPLACEMENTS = dict()
+
+
+def cmp(x, y):
+    return (x > y) - (x < y)
+
+
+class CmpTuple:
+    """Compare function between 2 tuple."""
+
+    def __call__(self, x, y):
+        return cmp(x[0], y[0])
+
+
+class CmpNode:
+    """Compare function between 2 xml nodes."""
+
+    def __call__(self, x, y):
+        def get_string(node):
+            node_string = "node"
+            node_string += node.nodeName
+            if node.nodeValue:
+                node_string += node.nodeValue
+
+            if node.attributes:
+                # We first sort by name, if present.
+                node_string += node.getAttribute("Name")
+
+                all_nodes = []
+                for (name, value) in node.attributes.items():
+                    all_nodes.append((name, value))
+
+                all_nodes.sort(CmpTuple())
+                for (name, value) in all_nodes:
+                    node_string += name
+                    node_string += value
+
+            return node_string
+
+        return cmp(get_string(x), get_string(y))
+
+
+def PrettyPrintNode(node, indent=0):
+    if node.nodeType == Node.TEXT_NODE:
+        if node.data.strip():
+            print("{}{}".format(" " * indent, node.data.strip()))
+        return
+
+    if node.childNodes:
+        node.normalize()
+    # Get the number of attributes
+    attr_count = 0
+    if node.attributes:
+        attr_count = node.attributes.length
+
+    # Print the main tag
+    if attr_count == 0:
+        print("{}<{}>".format(" " * indent, node.nodeName))
+    else:
+        print("{}<{}".format(" " * indent, node.nodeName))
+
+        all_attributes = []
+        for (name, value) in node.attributes.items():
+            all_attributes.append((name, value))
+            all_attributes.sort(CmpTuple())
+        for (name, value) in all_attributes:
+            print('{}  {}="{}"'.format(" " * indent, name, value))
+        print("%s>" % (" " * indent))
+    if node.nodeValue:
+        print("{}  {}".format(" " * indent, node.nodeValue))
+
+    for sub_node in node.childNodes:
+        PrettyPrintNode(sub_node, indent=indent + 2)
+    print("{}</{}>".format(" " * indent, node.nodeName))
+
+
+def FlattenFilter(node):
+    """Returns a list of all the node and sub nodes."""
+    node_list = []
+
+    if node.attributes and node.getAttribute("Name") == "_excluded_files":
+        # We don't add the "_excluded_files" filter.
+        return []
+
+    for current in node.childNodes:
+        if current.nodeName == "Filter":
+            node_list.extend(FlattenFilter(current))
+        else:
+            node_list.append(current)
+
+    return node_list
+
+
+def FixFilenames(filenames, current_directory):
+    new_list = []
+    for filename in filenames:
+        if filename:
+            for key in REPLACEMENTS:
+                filename = filename.replace(key, REPLACEMENTS[key])
+            os.chdir(current_directory)
+            filename = filename.strip("\"' ")
+            if filename.startswith("$"):
+                new_list.append(filename)
+            else:
+                new_list.append(os.path.abspath(filename))
+    return new_list
+
+
+def AbsoluteNode(node):
+    """Makes all the properties we know about in this node absolute."""
+    if node.attributes:
+        for (name, value) in node.attributes.items():
+            if name in [
+                "InheritedPropertySheets",
+                "RelativePath",
+                "AdditionalIncludeDirectories",
+                "IntermediateDirectory",
+                "OutputDirectory",
+                "AdditionalLibraryDirectories",
+            ]:
+                # We want to fix up these paths
+                path_list = value.split(";")
+                new_list = FixFilenames(path_list, os.path.dirname(ARGUMENTS[1]))
+                node.setAttribute(name, ";".join(new_list))
+            if not value:
+                node.removeAttribute(name)
+
+
+def CleanupVcproj(node):
+    """For each sub node, we call recursively this function."""
+    for sub_node in node.childNodes:
+        AbsoluteNode(sub_node)
+        CleanupVcproj(sub_node)
+
+    # Normalize the node, and remove all extraneous whitespaces.
+    for sub_node in node.childNodes:
+        if sub_node.nodeType == Node.TEXT_NODE:
+            sub_node.data = sub_node.data.replace("\r", "")
+            sub_node.data = sub_node.data.replace("\n", "")
+            sub_node.data = sub_node.data.rstrip()
+
+    # Fix all the semicolon separated attributes to be sorted, and we also
+    # remove the dups.
+    if node.attributes:
+        for (name, value) in node.attributes.items():
+            sorted_list = sorted(value.split(";"))
+            unique_list = []
+            for i in sorted_list:
+                if not unique_list.count(i):
+                    unique_list.append(i)
+            node.setAttribute(name, ";".join(unique_list))
+            if not value:
+                node.removeAttribute(name)
+
+    if node.childNodes:
+        node.normalize()
+
+    # For each node, take a copy, and remove it from the list.
+    node_array = []
+    while node.childNodes and node.childNodes[0]:
+        # Take a copy of the node and remove it from the list.
+        current = node.childNodes[0]
+        node.removeChild(current)
+
+        # If the child is a filter, we want to append all its children
+        # to this same list.
+        if current.nodeName == "Filter":
+            node_array.extend(FlattenFilter(current))
+        else:
+            node_array.append(current)
+
+    # Sort the list.
+    node_array.sort(CmpNode())
+
+    # Insert the nodes in the correct order.
+    for new_node in node_array:
+        # But don't append empty tool node.
+        if new_node.nodeName == "Tool":
+            if new_node.attributes and new_node.attributes.length == 1:
+                # This one was empty.
+                continue
+        if new_node.nodeName == "UserMacro":
+            continue
+        node.appendChild(new_node)
+
+
+def GetConfiguationNodes(vcproj):
+    # TODO(nsylvain): Find a better way to navigate the xml.
+    nodes = []
+    for node in vcproj.childNodes:
+        if node.nodeName == "Configurations":
+            for sub_node in node.childNodes:
+                if sub_node.nodeName == "Configuration":
+                    nodes.append(sub_node)
+
+    return nodes
+
+
+def GetChildrenVsprops(filename):
+    dom = parse(filename)
+    if dom.documentElement.attributes:
+        vsprops = dom.documentElement.getAttribute("InheritedPropertySheets")
+        return FixFilenames(vsprops.split(";"), os.path.dirname(filename))
+    return []
+
+
+def SeekToNode(node1, child2):
+    # A text node does not have properties.
+    if child2.nodeType == Node.TEXT_NODE:
+        return None
+
+    # Get the name of the current node.
+    current_name = child2.getAttribute("Name")
+    if not current_name:
+        # There is no name. We don't know how to merge.
+        return None
+
+    # Look through all the nodes to find a match.
+    for sub_node in node1.childNodes:
+        if sub_node.nodeName == child2.nodeName:
+            name = sub_node.getAttribute("Name")
+            if name == current_name:
+                return sub_node
+
+    # No match. We give up.
+    return None
+
+
+def MergeAttributes(node1, node2):
+    # No attributes to merge?
+    if not node2.attributes:
+        return
+
+    for (name, value2) in node2.attributes.items():
+        # Don't merge the 'Name' attribute.
+        if name == "Name":
+            continue
+        value1 = node1.getAttribute(name)
+        if value1:
+            # The attribute exist in the main node. If it's equal, we leave it
+            # untouched, otherwise we concatenate it.
+            if value1 != value2:
+                node1.setAttribute(name, ";".join([value1, value2]))
+        else:
+            # The attribute does not exist in the main node. We append this one.
+            node1.setAttribute(name, value2)
+
+        # If the attribute was a property sheet attributes, we remove it, since
+        # they are useless.
+        if name == "InheritedPropertySheets":
+            node1.removeAttribute(name)
+
+
+def MergeProperties(node1, node2):
+    MergeAttributes(node1, node2)
+    for child2 in node2.childNodes:
+        child1 = SeekToNode(node1, child2)
+        if child1:
+            MergeProperties(child1, child2)
+        else:
+            node1.appendChild(child2.cloneNode(True))
+
+
+def main(argv):
+    """Main function of this vcproj prettifier."""
+    global ARGUMENTS
+    ARGUMENTS = argv
+
+    # check if we have exactly 1 parameter.
+    if len(argv) < 2:
+        print(
+            'Usage: %s "c:\\path\\to\\vcproj.vcproj" [key1=value1] '
+            "[key2=value2]" % argv[0]
+        )
+        return 1
+
+    # Parse the keys
+    for i in range(2, len(argv)):
+        (key, value) = argv[i].split("=")
+        REPLACEMENTS[key] = value
+
+    # Open the vcproj and parse the xml.
+    dom = parse(argv[1])
+
+    # First thing we need to do is find the Configuration Node and merge them
+    # with the vsprops they include.
+    for configuration_node in GetConfiguationNodes(dom.documentElement):
+        # Get the property sheets associated with this configuration.
+        vsprops = configuration_node.getAttribute("InheritedPropertySheets")
+
+        # Fix the filenames to be absolute.
+        vsprops_list = FixFilenames(
+            vsprops.strip().split(";"), os.path.dirname(argv[1])
+        )
+
+        # Extend the list of vsprops with all vsprops contained in the current
+        # vsprops.
+        for current_vsprops in vsprops_list:
+            vsprops_list.extend(GetChildrenVsprops(current_vsprops))
+
+        # Now that we have all the vsprops, we need to merge them.
+        for current_vsprops in vsprops_list:
+            MergeProperties(configuration_node, parse(current_vsprops).documentElement)
+
+    # Now that everything is merged, we need to cleanup the xml.
+    CleanupVcproj(dom.documentElement)
+
+    # Finally, we use the prett xml function to print the vcproj back to the
+    # user.
+    # print dom.toprettyxml(newl="\n")
+    PrettyPrintNode(dom.documentElement)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv))
diff --git a/server/node_modules/node-gyp/lib/Find-VisualStudio.cs b/server/node_modules/node-gyp/lib/Find-VisualStudio.cs
new file mode 100644
index 0000000..d2e45a7
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/Find-VisualStudio.cs
@@ -0,0 +1,250 @@
+// Copyright 2017 - Refael Ackermann
+// Distributed under MIT style license
+// See accompanying file LICENSE at https://github.com/node4good/windows-autoconf
+
+// Usage:
+// powershell -ExecutionPolicy Unrestricted -Command "Add-Type -Path Find-VisualStudio.cs; [VisualStudioConfiguration.Main]::PrintJson()"
+// This script needs to be compatible with PowerShell v2 to run on Windows 2008R2 and Windows 7.
+
+using System;
+using System.Text;
+using System.Runtime.InteropServices;
+using System.Collections.Generic;
+
+namespace VisualStudioConfiguration
+{
+    [Flags]
+    public enum InstanceState : uint
+    {
+        None = 0,
+        Local = 1,
+        Registered = 2,
+        NoRebootRequired = 4,
+        NoErrors = 8,
+        Complete = 4294967295,
+    }
+
+    [Guid("6380BCFF-41D3-4B2E-8B2E-BF8A6810C848")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    [ComImport]
+    public interface IEnumSetupInstances
+    {
+
+        void Next([MarshalAs(UnmanagedType.U4), In] int celt,
+            [MarshalAs(UnmanagedType.LPArray, ArraySubType = UnmanagedType.Interface), Out] ISetupInstance[] rgelt,
+            [MarshalAs(UnmanagedType.U4)] out int pceltFetched);
+
+        void Skip([MarshalAs(UnmanagedType.U4), In] int celt);
+
+        void Reset();
+
+        [return: MarshalAs(UnmanagedType.Interface)]
+        IEnumSetupInstances Clone();
+    }
+
+    [Guid("42843719-DB4C-46C2-8E7C-64F1816EFD5B")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    [ComImport]
+    public interface ISetupConfiguration
+    {
+    }
+
+    [Guid("26AAB78C-4A60-49D6-AF3B-3C35BC93365D")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    [ComImport]
+    public interface ISetupConfiguration2 : ISetupConfiguration
+    {
+
+        [return: MarshalAs(UnmanagedType.Interface)]
+        IEnumSetupInstances EnumInstances();
+
+        [return: MarshalAs(UnmanagedType.Interface)]
+        ISetupInstance GetInstanceForCurrentProcess();
+
+        [return: MarshalAs(UnmanagedType.Interface)]
+        ISetupInstance GetInstanceForPath([MarshalAs(UnmanagedType.LPWStr), In] string path);
+
+        [return: MarshalAs(UnmanagedType.Interface)]
+        IEnumSetupInstances EnumAllInstances();
+    }
+
+    [Guid("B41463C3-8866-43B5-BC33-2B0676F7F42E")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    [ComImport]
+    public interface ISetupInstance
+    {
+    }
+
+    [Guid("89143C9A-05AF-49B0-B717-72E218A2185C")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    [ComImport]
+    public interface ISetupInstance2 : ISetupInstance
+    {
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetInstanceId();
+
+        [return: MarshalAs(UnmanagedType.Struct)]
+        System.Runtime.InteropServices.ComTypes.FILETIME GetInstallDate();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetInstallationName();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetInstallationPath();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetInstallationVersion();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetDisplayName([MarshalAs(UnmanagedType.U4), In] int lcid);
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetDescription([MarshalAs(UnmanagedType.U4), In] int lcid);
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string ResolvePath([MarshalAs(UnmanagedType.LPWStr), In] string pwszRelativePath);
+
+        [return: MarshalAs(UnmanagedType.U4)]
+        InstanceState GetState();
+
+        [return: MarshalAs(UnmanagedType.SafeArray, SafeArraySubType = VarEnum.VT_UNKNOWN)]
+        ISetupPackageReference[] GetPackages();
+
+        ISetupPackageReference GetProduct();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetProductPath();
+
+        [return: MarshalAs(UnmanagedType.VariantBool)]
+        bool IsLaunchable();
+
+        [return: MarshalAs(UnmanagedType.VariantBool)]
+        bool IsComplete();
+
+        [return: MarshalAs(UnmanagedType.SafeArray, SafeArraySubType = VarEnum.VT_UNKNOWN)]
+        ISetupPropertyStore GetProperties();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetEnginePath();
+    }
+
+    [Guid("DA8D8A16-B2B6-4487-A2F1-594CCCCD6BF5")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    [ComImport]
+    public interface ISetupPackageReference
+    {
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetId();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetVersion();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetChip();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetLanguage();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetBranch();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetType();
+
+        [return: MarshalAs(UnmanagedType.BStr)]
+        string GetUniqueId();
+
+        [return: MarshalAs(UnmanagedType.VariantBool)]
+        bool GetIsExtension();
+    }
+
+    [Guid("c601c175-a3be-44bc-91f6-4568d230fc83")]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    [ComImport]
+    public interface ISetupPropertyStore
+    {
+
+        [return: MarshalAs(UnmanagedType.SafeArray, SafeArraySubType = VarEnum.VT_BSTR)]
+        string[] GetNames();
+
+        object GetValue([MarshalAs(UnmanagedType.LPWStr), In] string pwszName);
+    }
+
+    [Guid("42843719-DB4C-46C2-8E7C-64F1816EFD5B")]
+    [CoClass(typeof(SetupConfigurationClass))]
+    [ComImport]
+    public interface SetupConfiguration : ISetupConfiguration2, ISetupConfiguration
+    {
+    }
+
+    [Guid("177F0C4A-1CD3-4DE7-A32C-71DBBB9FA36D")]
+    [ClassInterface(ClassInterfaceType.None)]
+    [ComImport]
+    public class SetupConfigurationClass
+    {
+    }
+
+    public static class Main
+    {
+        public static void PrintJson()
+        {
+            ISetupConfiguration query = new SetupConfiguration();
+            ISetupConfiguration2 query2 = (ISetupConfiguration2)query;
+            IEnumSetupInstances e = query2.EnumAllInstances();
+
+            int pceltFetched;
+            ISetupInstance2[] rgelt = new ISetupInstance2[1];
+            List<string> instances = new List<string>();
+            while (true)
+            {
+                e.Next(1, rgelt, out pceltFetched);
+                if (pceltFetched <= 0)
+                {
+                    Console.WriteLine(String.Format("[{0}]", string.Join(",", instances.ToArray())));
+                    return;
+                }
+
+                try
+                {
+                    instances.Add(InstanceJson(rgelt[0]));
+                }
+                catch (COMException)
+                {
+                    // Ignore instances that can't be queried.
+                }
+            }
+        }
+
+        private static string JsonString(string s)
+        {
+            return "\"" + s.Replace("\\", "\\\\").Replace("\"", "\\\"") + "\"";
+        }
+
+        private static string InstanceJson(ISetupInstance2 setupInstance2)
+        {
+            // Visual Studio component directory:
+            // https://docs.microsoft.com/en-us/visualstudio/install/workload-and-component-ids
+
+            StringBuilder json = new StringBuilder();
+            json.Append("{");
+
+            string path = JsonString(setupInstance2.GetInstallationPath());
+            json.Append(String.Format("\"path\":{0},", path));
+
+            string version = JsonString(setupInstance2.GetInstallationVersion());
+            json.Append(String.Format("\"version\":{0},", version));
+
+            List<string> packages = new List<string>();
+            foreach (ISetupPackageReference package in setupInstance2.GetPackages())
+            {
+                string id = JsonString(package.GetId());
+                packages.Add(id);
+            }
+            json.Append(String.Format("\"packages\":[{0}]", string.Join(",", packages.ToArray())));
+
+            json.Append("}");
+            return json.ToString();
+        }
+    }
+}
diff --git a/server/node_modules/node-gyp/lib/build.js b/server/node_modules/node-gyp/lib/build.js
new file mode 100644
index 0000000..c2388fb
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/build.js
@@ -0,0 +1,204 @@
+'use strict'
+
+const fs = require('graceful-fs')
+const path = require('path')
+const glob = require('glob')
+const log = require('npmlog')
+const which = require('which')
+const win = process.platform === 'win32'
+
+function build (gyp, argv, callback) {
+  var platformMake = 'make'
+  if (process.platform === 'aix') {
+    platformMake = 'gmake'
+  } else if (process.platform.indexOf('bsd') !== -1) {
+    platformMake = 'gmake'
+  } else if (win && argv.length > 0) {
+    argv = argv.map(function (target) {
+      return '/t:' + target
+    })
+  }
+
+  var makeCommand = gyp.opts.make || process.env.MAKE || platformMake
+  var command = win ? 'msbuild' : makeCommand
+  var jobs = gyp.opts.jobs || process.env.JOBS
+  var buildType
+  var config
+  var arch
+  var nodeDir
+  var guessedSolution
+
+  loadConfigGypi()
+
+  /**
+   * Load the "config.gypi" file that was generated during "configure".
+   */
+
+  function loadConfigGypi () {
+    var configPath = path.resolve('build', 'config.gypi')
+
+    fs.readFile(configPath, 'utf8', function (err, data) {
+      if (err) {
+        if (err.code === 'ENOENT') {
+          callback(new Error('You must run `node-gyp configure` first!'))
+        } else {
+          callback(err)
+        }
+        return
+      }
+      config = JSON.parse(data.replace(/#.+\n/, ''))
+
+      // get the 'arch', 'buildType', and 'nodeDir' vars from the config
+      buildType = config.target_defaults.default_configuration
+      arch = config.variables.target_arch
+      nodeDir = config.variables.nodedir
+
+      if ('debug' in gyp.opts) {
+        buildType = gyp.opts.debug ? 'Debug' : 'Release'
+      }
+      if (!buildType) {
+        buildType = 'Release'
+      }
+
+      log.verbose('build type', buildType)
+      log.verbose('architecture', arch)
+      log.verbose('node dev dir', nodeDir)
+
+      if (win) {
+        findSolutionFile()
+      } else {
+        doWhich()
+      }
+    })
+  }
+
+  /**
+   * On Windows, find the first build/*.sln file.
+   */
+
+  function findSolutionFile () {
+    glob('build/*.sln', function (err, files) {
+      if (err) {
+        return callback(err)
+      }
+      if (files.length === 0) {
+        return callback(new Error('Could not find *.sln file. Did you run "configure"?'))
+      }
+      guessedSolution = files[0]
+      log.verbose('found first Solution file', guessedSolution)
+      doWhich()
+    })
+  }
+
+  /**
+   * Uses node-which to locate the msbuild / make executable.
+   */
+
+  function doWhich () {
+    // On Windows use msbuild provided by node-gyp configure
+    if (win) {
+      if (!config.variables.msbuild_path) {
+        return callback(new Error(
+          'MSBuild is not set, please run `node-gyp configure`.'))
+      }
+      command = config.variables.msbuild_path
+      log.verbose('using MSBuild:', command)
+      doBuild()
+      return
+    }
+    // First make sure we have the build command in the PATH
+    which(command, function (err, execPath) {
+      if (err) {
+        // Some other error or 'make' not found on Unix, report that to the user
+        callback(err)
+        return
+      }
+      log.verbose('`which` succeeded for `' + command + '`', execPath)
+      doBuild()
+    })
+  }
+
+  /**
+   * Actually spawn the process and compile the module.
+   */
+
+  function doBuild () {
+    // Enable Verbose build
+    var verbose = log.levels[log.level] <= log.levels.verbose
+    var j
+
+    if (!win && verbose) {
+      argv.push('V=1')
+    }
+
+    if (win && !verbose) {
+      argv.push('/clp:Verbosity=minimal')
+    }
+
+    if (win) {
+      // Turn off the Microsoft logo on Windows
+      argv.push('/nologo')
+    }
+
+    // Specify the build type, Release by default
+    if (win) {
+      // Convert .gypi config target_arch to MSBuild /Platform
+      // Since there are many ways to state '32-bit Intel', default to it.
+      // N.B. msbuild's Condition string equality tests are case-insensitive.
+      var archLower = arch.toLowerCase()
+      var p = archLower === 'x64' ? 'x64'
+        : (archLower === 'arm' ? 'ARM'
+          : (archLower === 'arm64' ? 'ARM64' : 'Win32'))
+      argv.push('/p:Configuration=' + buildType + ';Platform=' + p)
+      if (jobs) {
+        j = parseInt(jobs, 10)
+        if (!isNaN(j) && j > 0) {
+          argv.push('/m:' + j)
+        } else if (jobs.toUpperCase() === 'MAX') {
+          argv.push('/m:' + require('os').cpus().length)
+        }
+      }
+    } else {
+      argv.push('BUILDTYPE=' + buildType)
+      // Invoke the Makefile in the 'build' dir.
+      argv.push('-C')
+      argv.push('build')
+      if (jobs) {
+        j = parseInt(jobs, 10)
+        if (!isNaN(j) && j > 0) {
+          argv.push('--jobs')
+          argv.push(j)
+        } else if (jobs.toUpperCase() === 'MAX') {
+          argv.push('--jobs')
+          argv.push(require('os').cpus().length)
+        }
+      }
+    }
+
+    if (win) {
+      // did the user specify their own .sln file?
+      var hasSln = argv.some(function (arg) {
+        return path.extname(arg) === '.sln'
+      })
+      if (!hasSln) {
+        argv.unshift(gyp.opts.solution || guessedSolution)
+      }
+    }
+
+    var proc = gyp.spawn(command, argv)
+    proc.on('exit', onExit)
+  }
+
+  function onExit (code, signal) {
+    if (code !== 0) {
+      return callback(new Error('`' + command + '` failed with exit code: ' + code))
+    }
+    if (signal) {
+      return callback(new Error('`' + command + '` got signal: ' + signal))
+    }
+    callback()
+  }
+}
+
+module.exports = build
+module.exports.usage = 'Invokes `' + (win ? 'msbuild' : 'make') + '` and builds the module'
diff --git a/server/node_modules/node-gyp/lib/clean.js b/server/node_modules/node-gyp/lib/clean.js
new file mode 100644
index 0000000..dbfa4db
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/clean.js
@@ -0,0 +1,15 @@
+'use strict'
+
+const rm = require('rimraf')
+const log = require('npmlog')
+
+function clean (gyp, argv, callback) {
+  // Remove the 'build' dir
+  var buildDir = 'build'
+
+  log.verbose('clean', 'removing "%s" directory', buildDir)
+  rm(buildDir, callback)
+}
+
+module.exports = clean
+module.exports.usage = 'Removes any generated build files and the "out" dir'
diff --git a/server/node_modules/node-gyp/lib/configure.js b/server/node_modules/node-gyp/lib/configure.js
new file mode 100644
index 0000000..d9b8fe3
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/configure.js
@@ -0,0 +1,294 @@
+'use strict'
+
+const fs = require('graceful-fs')
+const path = require('path')
+const log = require('npmlog')
+const os = require('os')
+const processRelease = require('./process-release')
+const win = process.platform === 'win32'
+const findNodeDirectory = require('./find-node-directory')
+const createConfigGypi = require('./create-config-gypi')
+const msgFormat = require('util').format
+var findPython = require('./find-python')
+if (win) {
+  var findVisualStudio = require('./find-visualstudio')
+}
+
+function configure (gyp, argv, callback) {
+  var python
+  var buildDir = path.resolve('build')
+  var configNames = ['config.gypi', 'common.gypi']
+  var configs = []
+  var nodeDir
+  var release = processRelease(argv, gyp, process.version, process.release)
+
+  findPython(gyp.opts.python, function (err, found) {
+    if (err) {
+      callback(err)
+    } else {
+      python = found
+      getNodeDir()
+    }
+  })
+
+  function getNodeDir () {
+    // 'python' should be set by now
+    process.env.PYTHON = python
+
+    if (gyp.opts.nodedir) {
+      // --nodedir was specified. use that for the dev files
+      nodeDir = gyp.opts.nodedir.replace(/^~/, os.homedir())
+
+      log.verbose('get node dir', 'compiling against specified --nodedir dev files: %s', nodeDir)
+      createBuildDir()
+    } else {
+      // if no --nodedir specified, ensure node dependencies are installed
+      if ('v' + release.version !== process.version) {
+        // if --target was given, then determine a target version to compile for
+        log.verbose('get node dir', 'compiling against --target node version: %s', release.version)
+      } else {
+        // if no --target was specified then use the current host node version
+        log.verbose('get node dir', 'no --target version specified, falling back to host node version: %s', release.version)
+      }
+
+      if (!release.semver) {
+        // could not parse the version string with semver
+        return callback(new Error('Invalid version number: ' + release.version))
+      }
+
+      // If the tarball option is set, always remove and reinstall the headers
+      // into devdir. Otherwise only install if they're not already there.
+      gyp.opts.ensure = !gyp.opts.tarball
+
+      gyp.commands.install([release.version], function (err) {
+        if (err) {
+          return callback(err)
+        }
+        log.verbose('get node dir', 'target node version installed:', release.versionDir)
+        nodeDir = path.resolve(gyp.devDir, release.versionDir)
+        createBuildDir()
+      })
+    }
+  }
+
+  function createBuildDir () {
+    log.verbose('build dir', 'attempting to create "build" dir: %s', buildDir)
+    fs.mkdir(buildDir, { recursive: true }, function (err, isNew) {
+      if (err) {
+        return callback(err)
+      }
+      log.verbose(
+        'build dir', '"build" dir needed to be created?', isNew ? 'Yes' : 'No'
+      )
+      if (win) {
+        findVisualStudio(release.semver, gyp.opts.msvs_version,
+          createConfigFile)
+      } else {
+        createConfigFile()
+      }
+    })
+  }
+
+  function createConfigFile (err, vsInfo) {
+    if (err) {
+      return callback(err)
+    }
+    if (process.platform === 'win32') {
+      process.env.GYP_MSVS_VERSION = Math.min(vsInfo.versionYear, 2015)
+      process.env.GYP_MSVS_OVERRIDE_PATH = vsInfo.path
+    }
+    createConfigGypi({ gyp, buildDir, nodeDir, vsInfo }).then(configPath => {
+      configs.push(configPath)
+      findConfigs()
+    }).catch(err => {
+      callback(err)
+    })
+  }
+
+  function findConfigs () {
+    var name = configNames.shift()
+    if (!name) {
+      return runGyp()
+    }
+    var fullPath = path.resolve(name)
+
+    log.verbose(name, 'checking for gypi file: %s', fullPath)
+    fs.stat(fullPath, function (err) {
+      if (err) {
+        if (err.code === 'ENOENT') {
+          findConfigs() // check next gypi filename
+        } else {
+          callback(err)
+        }
+      } else {
+        log.verbose(name, 'found gypi file')
+        configs.push(fullPath)
+        findConfigs()
+      }
+    })
+  }
+
+  function runGyp (err) {
+    if (err) {
+      return callback(err)
+    }
+
+    if (!~argv.indexOf('-f') && !~argv.indexOf('--format')) {
+      if (win) {
+        log.verbose('gyp', 'gyp format was not specified; forcing "msvs"')
+        // force the 'make' target for non-Windows
+        argv.push('-f', 'msvs')
+      } else {
+        log.verbose('gyp', 'gyp format was not specified; forcing "make"')
+        // force the 'make' target for non-Windows
+        argv.push('-f', 'make')
+      }
+    }
+
+    // include all the ".gypi" files that were found
+    configs.forEach(function (config) {
+      argv.push('-I', config)
+    })
+
+    // For AIX and z/OS we need to set up the path to the exports file
+    // which contains the symbols needed for linking.
+    var nodeExpFile
+    if (process.platform === 'aix' || process.platform === 'os390') {
+      var ext = process.platform === 'aix' ? 'exp' : 'x'
+      var nodeRootDir = findNodeDirectory()
+      var candidates
+
+      if (process.platform === 'aix') {
+        candidates = [
+          'include/node/node',
+          'out/Release/node',
+          'out/Debug/node',
+          'node'
+        ].map(function (file) {
+          return file + '.' + ext
+        })
+      } else {
+        candidates = [
+          'out/Release/obj.target/libnode',
+          'out/Debug/obj.target/libnode',
+          'lib/libnode'
+        ].map(function (file) {
+          return file + '.' + ext
+        })
+      }
+
+      var logprefix = 'find exports file'
+      nodeExpFile = findAccessibleSync(logprefix, nodeRootDir, candidates)
+      if (nodeExpFile !== undefined) {
+        log.verbose(logprefix, 'Found exports file: %s', nodeExpFile)
+      } else {
+        var msg = msgFormat('Could not find node.%s file in %s', ext, nodeRootDir)
+        log.error(logprefix, 'Could not find exports file')
+        return callback(new Error(msg))
+      }
+    }
+
+    // this logic ported from the old `gyp_addon` python file
+    var gypScript = path.resolve(__dirname, '..', 'gyp', 'gyp_main.py')
+    var addonGypi = path.resolve(__dirname, '..', 'addon.gypi')
+    var commonGypi = path.resolve(nodeDir, 'include/node/common.gypi')
+    fs.stat(commonGypi, function (err) {
+      if (err) {
+        commonGypi = path.resolve(nodeDir, 'common.gypi')
+      }
+
+      var outputDir = 'build'
+      if (win) {
+        // Windows expects an absolute path
+        outputDir = buildDir
+      }
+      var nodeGypDir = path.resolve(__dirname, '..')
+
+      var nodeLibFile = path.join(nodeDir,
+        !gyp.opts.nodedir ? '<(target_arch)' : '$(Configuration)',
+        release.name + '.lib')
+
+      argv.push('-I', addonGypi)
+      argv.push('-I', commonGypi)
+      argv.push('-Dlibrary=shared_library')
+      argv.push('-Dvisibility=default')
+      argv.push('-Dnode_root_dir=' + nodeDir)
+      if (process.platform === 'aix' || process.platform === 'os390') {
+        argv.push('-Dnode_exp_file=' + nodeExpFile)
+      }
+      argv.push('-Dnode_gyp_dir=' + nodeGypDir)
+
+      // Do this to keep Cygwin environments happy, else the unescaped '\' gets eaten up,
+      // resulting in bad paths, Ex c:parentFolderfolderanotherFolder instead of c:\parentFolder\folder\anotherFolder
+      if (win) {
+        nodeLibFile = nodeLibFile.replace(/\\/g, '\\\\')
+      }
+      argv.push('-Dnode_lib_file=' + nodeLibFile)
+      argv.push('-Dmodule_root_dir=' + process.cwd())
+      argv.push('-Dnode_engine=' +
+        (gyp.opts.node_engine || process.jsEngine || 'v8'))
+      argv.push('--depth=.')
+      argv.push('--no-parallel')
+
+      // tell gyp to write the Makefile/Solution files into output_dir
+      argv.push('--generator-output', outputDir)
+
+      // tell make to write its output into the same dir
+      argv.push('-Goutput_dir=.')
+
+      // enforce use of the "binding.gyp" file
+      argv.unshift('binding.gyp')
+
+      // execute `gyp` from the current target nodedir
+      argv.unshift(gypScript)
+
+      // make sure python uses files that came with this particular node package
+      var pypath = [path.join(__dirname, '..', 'gyp', 'pylib')]
+      if (process.env.PYTHONPATH) {
+        pypath.push(process.env.PYTHONPATH)
+      }
+      process.env.PYTHONPATH = pypath.join(win ? ';' : ':')
+
+      var cp = gyp.spawn(python, argv)
+      cp.on('exit', onCpExit)
+    })
+  }
+
+  function onCpExit (code) {
+    if (code !== 0) {
+      callback(new Error('`gyp` failed with exit code: ' + code))
+    } else {
+      // we're done
+      callback()
+    }
+  }
+}
+
+/**
+ * Returns the first file or directory from an array of candidates that is
+ * readable by the current user, or undefined if none of the candidates are
+ * readable.
+ */
+function findAccessibleSync (logprefix, dir, candidates) {
+  for (var next = 0; next < candidates.length; next++) {
+    var candidate = path.resolve(dir, candidates[next])
+    try {
+      var fd = fs.openSync(candidate, 'r')
+    } catch (e) {
+      // this candidate was not found or not readable, do nothing
+      log.silly(logprefix, 'Could not open %s: %s', candidate, e.message)
+      continue
+    }
+    fs.closeSync(fd)
+    log.silly(logprefix, 'Found readable %s', candidate)
+    return candidate
+  }
+
+  return undefined
+}
+
+module.exports = configure
+module.exports.test = {
+  findAccessibleSync: findAccessibleSync
+}
+module.exports.usage = 'Generates ' + (win ? 'MSVC project files' : 'a Makefile') + ' for the current module'
diff --git a/server/node_modules/node-gyp/lib/create-config-gypi.js b/server/node_modules/node-gyp/lib/create-config-gypi.js
new file mode 100644
index 0000000..dbcb8b4
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/create-config-gypi.js
@@ -0,0 +1,146 @@
+'use strict'
+
+const fs = require('graceful-fs')
+const log = require('npmlog')
+const path = require('path')
+
+function parseConfigGypi (config) {
+  // translated from tools/js2c.py of Node.js
+  // 1. string comments
+  config = config.replace(/#.*/g, '')
+  // 2. join multiline strings
+  config = config.replace(/'$\s+'/mg, '')
+  // 3. normalize string literals from ' into "
+  config = config.replace(/'/g, '"')
+  return JSON.parse(config)
+}
+
+async function getBaseConfigGypi ({ gyp, nodeDir }) {
+  // try reading $nodeDir/include/node/config.gypi first when:
+  // 1. --dist-url or --nodedir is specified
+  // 2. and --force-process-config is not specified
+  const shouldReadConfigGypi = (gyp.opts.nodedir || gyp.opts['dist-url']) && !gyp.opts['force-process-config']
+  if (shouldReadConfigGypi && nodeDir) {
+    try {
+      const baseConfigGypiPath = path.resolve(nodeDir, 'include/node/config.gypi')
+      const baseConfigGypi = await fs.promises.readFile(baseConfigGypiPath)
+      return parseConfigGypi(baseConfigGypi.toString())
+    } catch (err) {
+      log.warn('read config.gypi', err.message)
+    }
+  }
+
+  // fallback to process.config if it is invalid
+  return JSON.parse(JSON.stringify(process.config))
+}
+
+async function getCurrentConfigGypi ({ gyp, nodeDir, vsInfo }) {
+  const config = await getBaseConfigGypi({ gyp, nodeDir })
+  if (!config.target_defaults) {
+    config.target_defaults = {}
+  }
+  if (!config.variables) {
+    config.variables = {}
+  }
+
+  const defaults = config.target_defaults
+  const variables = config.variables
+
+  // don't inherit the "defaults" from the base config.gypi.
+  // doing so could cause problems in cases where the `node` executable was
+  // compiled on a different machine (with different lib/include paths) than
+  // the machine where the addon is being built to
+  defaults.cflags = []
+  defaults.defines = []
+  defaults.include_dirs = []
+  defaults.libraries = []
+
+  // set the default_configuration prop
+  if ('debug' in gyp.opts) {
+    defaults.default_configuration = gyp.opts.debug ? 'Debug' : 'Release'
+  }
+
+  if (!defaults.default_configuration) {
+    defaults.default_configuration = 'Release'
+  }
+
+  // set the target_arch variable
+  variables.target_arch = gyp.opts.arch || process.arch || 'ia32'
+  if (variables.target_arch === 'arm64') {
+    defaults.msvs_configuration_platform = 'ARM64'
+    defaults.xcode_configuration_platform = 'arm64'
+  }
+
+  // set the node development directory
+  variables.nodedir = nodeDir
+
+  // disable -T "thin" static archives by default
+  variables.standalone_static_library = gyp.opts.thin ? 0 : 1
+
+  if (process.platform === 'win32') {
+    defaults.msbuild_toolset = vsInfo.toolset
+    if (vsInfo.sdk) {
+      defaults.msvs_windows_target_platform_version = vsInfo.sdk
+    }
+    if (variables.target_arch === 'arm64') {
+      if (vsInfo.versionMajor > 15 ||
+          (vsInfo.versionMajor === 15 && vsInfo.versionMajor >= 9)) {
+        defaults.msvs_enable_marmasm = 1
+      } else {
+        log.warn('Compiling ARM64 assembly is only available in\n' +
+          'Visual Studio 2017 version 15.9 and above')
+      }
+    }
+    variables.msbuild_path = vsInfo.msBuild
+  }
+
+  // loop through the rest of the opts and add the unknown ones as variables.
+  // this allows for module-specific configure flags like:
+  //
+  //   $ node-gyp configure --shared-libxml2
+  Object.keys(gyp.opts).forEach(function (opt) {
+    if (opt === 'argv') {
+      return
+    }
+    if (opt in gyp.configDefs) {
+      return
+    }
+    variables[opt.replace(/-/g, '_')] = gyp.opts[opt]
+  })
+
+  return config
+}
+
+async function createConfigGypi ({ gyp, buildDir, nodeDir, vsInfo }) {
+  const configFilename = 'config.gypi'
+  const configPath = path.resolve(buildDir, configFilename)
+
+  log.verbose('build/' + configFilename, 'creating config file')
+
+  const config = await getCurrentConfigGypi({ gyp, nodeDir, vsInfo })
+
+  // ensures that any boolean values in config.gypi get stringified
+  function boolsToString (k, v) {
+    if (typeof v === 'boolean') {
+      return String(v)
+    }
+    return v
+  }
+
+  log.silly('build/' + configFilename, config)
+
+  // now write out the config.gypi file to the build/ dir
+  const prefix = '# Do not edit. File was generated by node-gyp\'s "configure" step'
+
+  const json = JSON.stringify(config, boolsToString, 2)
+  log.verbose('build/' + configFilename, 'writing out config file: %s', configPath)
+  await fs.promises.writeFile(configPath, [prefix, json, ''].join('\n'))
+
+  return configPath
+}
+
+module.exports = createConfigGypi
+module.exports.test = {
+  parseConfigGypi: parseConfigGypi,
+  getCurrentConfigGypi: getCurrentConfigGypi
+}
diff --git a/server/node_modules/node-gyp/lib/find-node-directory.js b/server/node_modules/node-gyp/lib/find-node-directory.js
new file mode 100644
index 0000000..0dd781a
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/find-node-directory.js
@@ -0,0 +1,63 @@
+'use strict'
+
+const path = require('path')
+const log = require('npmlog')
+
+function findNodeDirectory (scriptLocation, processObj) {
+  // set dirname and process if not passed in
+  // this facilitates regression tests
+  if (scriptLocation === undefined) {
+    scriptLocation = __dirname
+  }
+  if (processObj === undefined) {
+    processObj = process
+  }
+
+  // Have a look to see what is above us, to try and work out where we are
+  var npmParentDirectory = path.join(scriptLocation, '../../../..')
+  log.verbose('node-gyp root', 'npm_parent_directory is ' +
+              path.basename(npmParentDirectory))
+  var nodeRootDir = ''
+
+  log.verbose('node-gyp root', 'Finding node root directory')
+  if (path.basename(npmParentDirectory) === 'deps') {
+    // We are in a build directory where this script lives in
+    // deps/npm/node_modules/node-gyp/lib
+    nodeRootDir = path.join(npmParentDirectory, '..')
+    log.verbose('node-gyp root', 'in build directory, root = ' +
+                nodeRootDir)
+  } else if (path.basename(npmParentDirectory) === 'node_modules') {
+    // We are in a node install directory where this script lives in
+    // lib/node_modules/npm/node_modules/node-gyp/lib or
+    // node_modules/npm/node_modules/node-gyp/lib depending on the
+    // platform
+    if (processObj.platform === 'win32') {
+      nodeRootDir = path.join(npmParentDirectory, '..')
+    } else {
+      nodeRootDir = path.join(npmParentDirectory, '../..')
+    }
+    log.verbose('node-gyp root', 'in install directory, root = ' +
+                nodeRootDir)
+  } else {
+    // We don't know where we are, try working it out from the location
+    // of the node binary
+    var nodeDir = path.dirname(processObj.execPath)
+    var directoryUp = path.basename(nodeDir)
+    if (directoryUp === 'bin') {
+      nodeRootDir = path.join(nodeDir, '..')
+    } else if (directoryUp === 'Release' || directoryUp === 'Debug') {
+      // If we are a recently built node, and the directory structure
+      // is that of a repository. If we are on Windows then we only need
+      // to go one level up, everything else, two
+      if (processObj.platform === 'win32') {
+        nodeRootDir = path.join(nodeDir, '..')
+      } else {
+        nodeRootDir = path.join(nodeDir, '../..')
+      }
+    }
+    // Else return the default blank, "".
+  }
+  return nodeRootDir
+}
+
+module.exports = findNodeDirectory
diff --git a/server/node_modules/node-gyp/lib/find-python.js b/server/node_modules/node-gyp/lib/find-python.js
new file mode 100644
index 0000000..a445e82
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/find-python.js
@@ -0,0 +1,344 @@
+'use strict'
+
+const log = require('npmlog')
+const semver = require('semver')
+const cp = require('child_process')
+const extend = require('util')._extend // eslint-disable-line
+const win = process.platform === 'win32'
+const logWithPrefix = require('./util').logWithPrefix
+
+const systemDrive = process.env.SystemDrive || 'C:'
+const username = process.env.USERNAME || process.env.USER || getOsUserInfo()
+const localAppData = process.env.LOCALAPPDATA || `${systemDrive}\\${username}\\AppData\\Local`
+const foundLocalAppData = process.env.LOCALAPPDATA || username
+const programFiles = process.env.ProgramW6432 || process.env.ProgramFiles || `${systemDrive}\\Program Files`
+const programFilesX86 = process.env['ProgramFiles(x86)'] || `${programFiles} (x86)`
+
+const winDefaultLocationsArray = []
+for (const majorMinor of ['39', '38', '37', '36']) {
+  if (foundLocalAppData) {
+    winDefaultLocationsArray.push(
+      `${localAppData}\\Programs\\Python\\Python${majorMinor}\\python.exe`,
+      `${programFiles}\\Python${majorMinor}\\python.exe`,
+      `${localAppData}\\Programs\\Python\\Python${majorMinor}-32\\python.exe`,
+      `${programFiles}\\Python${majorMinor}-32\\python.exe`,
+      `${programFilesX86}\\Python${majorMinor}-32\\python.exe`
+    )
+  } else {
+    winDefaultLocationsArray.push(
+      `${programFiles}\\Python${majorMinor}\\python.exe`,
+      `${programFiles}\\Python${majorMinor}-32\\python.exe`,
+      `${programFilesX86}\\Python${majorMinor}-32\\python.exe`
+    )
+  }
+}
+
+function getOsUserInfo () {
+  try {
+    return require('os').userInfo().username
+  } catch (e) {}
+}
+
+function PythonFinder (configPython, callback) {
+  this.callback = callback
+  this.configPython = configPython
+  this.errorLog = []
+}
+
+PythonFinder.prototype = {
+  log: logWithPrefix(log, 'find Python'),
+  argsExecutable: ['-c', 'import sys; print(sys.executable);'],
+  argsVersion: ['-c', 'import sys; print("%s.%s.%s" % sys.version_info[:3]);'],
+  semverRange: '>=3.6.0',
+
+  // These can be overridden for testing:
+  execFile: cp.execFile,
+  env: process.env,
+  win: win,
+  pyLauncher: 'py.exe',
+  winDefaultLocations: winDefaultLocationsArray,
+
+  // Logs a message at verbose level, but also saves it to be displayed later
+  // at error level if an error occurs. This should help diagnose the problem.
+  addLog: function addLog (message) {
+    this.log.verbose(message)
+    this.errorLog.push(message)
+  },
+
+  // Find Python by trying a sequence of possibilities.
+  // Ignore errors, keep trying until Python is found.
+  findPython: function findPython () {
+    const SKIP = 0; const FAIL = 1
+    var toCheck = getChecks.apply(this)
+
+    function getChecks () {
+      if (this.env.NODE_GYP_FORCE_PYTHON) {
+        return [{
+          before: () => {
+            this.addLog(
+              'checking Python explicitly set from NODE_GYP_FORCE_PYTHON')
+            this.addLog('- process.env.NODE_GYP_FORCE_PYTHON is ' +
+              `"${this.env.NODE_GYP_FORCE_PYTHON}"`)
+          },
+          check: this.checkCommand,
+          arg: this.env.NODE_GYP_FORCE_PYTHON
+        }]
+      }
+
+      var checks = [
+        {
+          before: () => {
+            if (!this.configPython) {
+              this.addLog(
+                'Python is not set from command line or npm configuration')
+              return SKIP
+            }
+            this.addLog('checking Python explicitly set from command line or ' +
+              'npm configuration')
+            this.addLog('- "--python=" or "npm config get python" is ' +
+              `"${this.configPython}"`)
+          },
+          check: this.checkCommand,
+          arg: this.configPython
+        },
+        {
+          before: () => {
+            if (!this.env.PYTHON) {
+              this.addLog('Python is not set from environment variable ' +
+                'PYTHON')
+              return SKIP
+            }
+            this.addLog('checking Python explicitly set from environment ' +
+              'variable PYTHON')
+            this.addLog(`- process.env.PYTHON is "${this.env.PYTHON}"`)
+          },
+          check: this.checkCommand,
+          arg: this.env.PYTHON
+        },
+        {
+          before: () => { this.addLog('checking if "python3" can be used') },
+          check: this.checkCommand,
+          arg: 'python3'
+        },
+        {
+          before: () => { this.addLog('checking if "python" can be used') },
+          check: this.checkCommand,
+          arg: 'python'
+        }
+      ]
+
+      if (this.win) {
+        for (var i = 0; i < this.winDefaultLocations.length; ++i) {
+          const location = this.winDefaultLocations[i]
+          checks.push({
+            before: () => {
+              this.addLog('checking if Python is ' +
+                `${location}`)
+            },
+            check: this.checkExecPath,
+            arg: location
+          })
+        }
+        checks.push({
+          before: () => {
+            this.addLog(
+              'checking if the py launcher can be used to find Python 3')
+          },
+          check: this.checkPyLauncher
+        })
+      }
+
+      return checks
+    }
+
+    function runChecks (err) {
+      this.log.silly('runChecks: err = %j', (err && err.stack) || err)
+
+      const check = toCheck.shift()
+      if (!check) {
+        return this.fail()
+      }
+
+      const before = check.before.apply(this)
+      if (before === SKIP) {
+        return runChecks.apply(this)
+      }
+      if (before === FAIL) {
+        return this.fail()
+      }
+
+      const args = [runChecks.bind(this)]
+      if (check.arg) {
+        args.unshift(check.arg)
+      }
+      check.check.apply(this, args)
+    }
+
+    runChecks.apply(this)
+  },
+
+  // Check if command is a valid Python to use.
+  // Will exit the Python finder on success.
+  // If on Windows, run in a CMD shell to support BAT/CMD launchers.
+  checkCommand: function checkCommand (command, errorCallback) {
+    var exec = command
+    var args = this.argsExecutable
+    var shell = false
+    if (this.win) {
+      // Arguments have to be manually quoted
+      exec = `"${exec}"`
+      args = args.map(a => `"${a}"`)
+      shell = true
+    }
+
+    this.log.verbose(`- executing "${command}" to get executable path`)
+    this.run(exec, args, shell, function (err, execPath) {
+      // Possible outcomes:
+      // - Error: not in PATH, not executable or execution fails
+      // - Gibberish: the next command to check version will fail
+      // - Absolute path to executable
+      if (err) {
+        this.addLog(`- "${command}" is not in PATH or produced an error`)
+        return errorCallback(err)
+      }
+      this.addLog(`- executable path is "${execPath}"`)
+      this.checkExecPath(execPath, errorCallback)
+    }.bind(this))
+  },
+
+  // Check if the py launcher can find a valid Python to use.
+  // Will exit the Python finder on success.
+  // Distributions of Python on Windows by default install with the "py.exe"
+  // Python launcher which is more likely to exist than the Python executable
+  // being in the $PATH.
+  // Because the Python launcher supports Python 2 and Python 3, we should
+  // explicitly request a Python 3 version. This is done by supplying "-3" as
+  // the first command line argument. Since "py.exe -3" would be an invalid
+  // executable for "execFile", we have to use the launcher to figure out
+  // where the actual "python.exe" executable is located.
+  checkPyLauncher: function checkPyLauncher (errorCallback) {
+    this.log.verbose(
+      `- executing "${this.pyLauncher}" to get Python 3 executable path`)
+    this.run(this.pyLauncher, ['-3', ...this.argsExecutable], false,
+      function (err, execPath) {
+      // Possible outcomes: same as checkCommand
+        if (err) {
+          this.addLog(
+            `- "${this.pyLauncher}" is not in PATH or produced an error`)
+          return errorCallback(err)
+        }
+        this.addLog(`- executable path is "${execPath}"`)
+        this.checkExecPath(execPath, errorCallback)
+      }.bind(this))
+  },
+
+  // Check if a Python executable is the correct version to use.
+  // Will exit the Python finder on success.
+  checkExecPath: function checkExecPath (execPath, errorCallback) {
+    this.log.verbose(`- executing "${execPath}" to get version`)
+    this.run(execPath, this.argsVersion, false, function (err, version) {
+      // Possible outcomes:
+      // - Error: executable can not be run (likely meaning the command wasn't
+      //   a Python executable and the previous command produced gibberish)
+      // - Gibberish: somehow the last command produced an executable path,
+      //   this will fail when verifying the version
+      // - Version of the Python executable
+      if (err) {
+        this.addLog(`- "${execPath}" could not be run`)
+        return errorCallback(err)
+      }
+      this.addLog(`- version is "${version}"`)
+
+      const range = new semver.Range(this.semverRange)
+      var valid = false
+      try {
+        valid = range.test(version)
+      } catch (err) {
+        this.log.silly('range.test() threw:\n%s', err.stack)
+        this.addLog(`- "${execPath}" does not have a valid version`)
+        this.addLog('- is it a Python executable?')
+        return errorCallback(err)
+      }
+
+      if (!valid) {
+        this.addLog(`- version is ${version} - should be ${this.semverRange}`)
+        this.addLog('- THIS VERSION OF PYTHON IS NOT SUPPORTED')
+        return errorCallback(new Error(
+          `Found unsupported Python version ${version}`))
+      }
+      this.succeed(execPath, version)
+    }.bind(this))
+  },
+
+  // Run an executable or shell command, trimming the output.
+  run: function run (exec, args, shell, callback) {
+    var env = extend({}, this.env)
+    env.TERM = 'dumb'
+    const opts = { env: env, shell: shell }
+
+    this.log.silly('execFile: exec = %j', exec)
+    this.log.silly('execFile: args = %j', args)
+    this.log.silly('execFile: opts = %j', opts)
+    try {
+      this.execFile(exec, args, opts, execFileCallback.bind(this))
+    } catch (err) {
+      this.log.silly('execFile: threw:\n%s', err.stack)
+      return callback(err)
+    }
+
+    function execFileCallback (err, stdout, stderr) {
+      this.log.silly('execFile result: err = %j', (err && err.stack) || err)
+      this.log.silly('execFile result: stdout = %j', stdout)
+      this.log.silly('execFile result: stderr = %j', stderr)
+      if (err) {
+        return callback(err)
+      }
+      const execPath = stdout.trim()
+      callback(null, execPath)
+    }
+  },
+
+  succeed: function succeed (execPath, version) {
+    this.log.info(`using Python version ${version} found at "${execPath}"`)
+    process.nextTick(this.callback.bind(null, null, execPath))
+  },
+
+  fail: function fail () {
+    const errorLog = this.errorLog.join('\n')
+
+    const pathExample = this.win ? 'C:\\Path\\To\\python.exe'
+      : '/path/to/pythonexecutable'
+    // For Windows 80 col console, use up to the column before the one marked
+    // with X (total 79 chars including logger prefix, 58 chars usable here):
+    //                                                           X
+    const info = [
+      '**********************************************************',
+      'You need to install the latest version of Python.',
+      'Node-gyp should be able to find and use Python. If not,',
+      'you can try one of the following options:',
+      `- Use the switch --python="${pathExample}"`,
+      '  (accepted by both node-gyp and npm)',
+      '- Set the environment variable PYTHON',
+      '- Set the npm configuration variable python:',
+      `  npm config set python "${pathExample}"`,
+      'For more information consult the documentation at:',
+      'https://github.com/nodejs/node-gyp#installation',
+      '**********************************************************'
+    ].join('\n')
+
+    this.log.error(`\n${errorLog}\n\n${info}\n`)
+    process.nextTick(this.callback.bind(null, new Error(
+      'Could not find any Python installation to use')))
+  }
+}
+
+function findPython (configPython, callback) {
+  var finder = new PythonFinder(configPython, callback)
+  finder.findPython()
+}
+
+module.exports = findPython
+module.exports.test = {
+  PythonFinder: PythonFinder,
+  findPython: findPython
+}
diff --git a/server/node_modules/node-gyp/lib/find-visualstudio.js b/server/node_modules/node-gyp/lib/find-visualstudio.js
new file mode 100644
index 0000000..64af7be
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/find-visualstudio.js
@@ -0,0 +1,446 @@
+'use strict'
+
+const log = require('npmlog')
+const execFile = require('child_process').execFile
+const fs = require('fs')
+const path = require('path').win32
+const logWithPrefix = require('./util').logWithPrefix
+const regSearchKeys = require('./util').regSearchKeys
+
+function findVisualStudio (nodeSemver, configMsvsVersion, callback) {
+  const finder = new VisualStudioFinder(nodeSemver, configMsvsVersion,
+    callback)
+  finder.findVisualStudio()
+}
+
+function VisualStudioFinder (nodeSemver, configMsvsVersion, callback) {
+  this.nodeSemver = nodeSemver
+  this.configMsvsVersion = configMsvsVersion
+  this.callback = callback
+  this.errorLog = []
+  this.validVersions = []
+}
+
+VisualStudioFinder.prototype = {
+  log: logWithPrefix(log, 'find VS'),
+
+  regSearchKeys: regSearchKeys,
+
+  // Logs a message at verbose level, but also saves it to be displayed later
+  // at error level if an error occurs. This should help diagnose the problem.
+  addLog: function addLog (message) {
+    this.log.verbose(message)
+    this.errorLog.push(message)
+  },
+
+  findVisualStudio: function findVisualStudio () {
+    this.configVersionYear = null
+    this.configPath = null
+    if (this.configMsvsVersion) {
+      this.addLog('msvs_version was set from command line or npm config')
+      if (this.configMsvsVersion.match(/^\d{4}$/)) {
+        this.configVersionYear = parseInt(this.configMsvsVersion, 10)
+        this.addLog(
+          `- looking for Visual Studio version ${this.configVersionYear}`)
+      } else {
+        this.configPath = path.resolve(this.configMsvsVersion)
+        this.addLog(
+          `- looking for Visual Studio installed in "${this.configPath}"`)
+      }
+    } else {
+      this.addLog('msvs_version not set from command line or npm config')
+    }
+
+    if (process.env.VCINSTALLDIR) {
+      this.envVcInstallDir =
+        path.resolve(process.env.VCINSTALLDIR, '..')
+      this.addLog('running in VS Command Prompt, installation path is:\n' +
+        `"${this.envVcInstallDir}"\n- will only use this version`)
+    } else {
+      this.addLog('VCINSTALLDIR not set, not running in VS Command Prompt')
+    }
+
+    this.findVisualStudio2017OrNewer((info) => {
+      if (info) {
+        return this.succeed(info)
+      }
+      this.findVisualStudio2015((info) => {
+        if (info) {
+          return this.succeed(info)
+        }
+        this.findVisualStudio2013((info) => {
+          if (info) {
+            return this.succeed(info)
+          }
+          this.fail()
+        })
+      })
+    })
+  },
+
+  succeed: function succeed (info) {
+    this.log.info(`using VS${info.versionYear} (${info.version}) found at:` +
+                  `\n"${info.path}"` +
+                  '\nrun with --verbose for detailed information')
+    process.nextTick(this.callback.bind(null, null, info))
+  },
+
+  fail: function fail () {
+    if (this.configMsvsVersion && this.envVcInstallDir) {
+      this.errorLog.push(
+        'msvs_version does not match this VS Command Prompt or the',
+        'installation cannot be used.')
+    } else if (this.configMsvsVersion) {
+      // If msvs_version was specified but finding VS failed, print what would
+      // have been accepted
+      this.errorLog.push('')
+      if (this.validVersions) {
+        this.errorLog.push('valid versions for msvs_version:')
+        this.validVersions.forEach((version) => {
+          this.errorLog.push(`- "${version}"`)
+        })
+      } else {
+        this.errorLog.push('no valid versions for msvs_version were found')
+      }
+    }
+
+    const errorLog = this.errorLog.join('\n')
+
+    // For Windows 80 col console, use up to the column before the one marked
+    // with X (total 79 chars including logger prefix, 62 chars usable here):
+    //                                                               X
+    const infoLog = [
+      '**************************************************************',
+      'You need to install the latest version of Visual Studio',
+      'including the "Desktop development with C++" workload.',
+      'For more information consult the documentation at:',
+      'https://github.com/nodejs/node-gyp#on-windows',
+      '**************************************************************'
+    ].join('\n')
+
+    this.log.error(`\n${errorLog}\n\n${infoLog}\n`)
+    process.nextTick(this.callback.bind(null, new Error(
+      'Could not find any Visual Studio installation to use')))
+  },
+
+  // Invoke the PowerShell script to get information about Visual Studio 2017
+  // or newer installations
+  findVisualStudio2017OrNewer: function findVisualStudio2017OrNewer (cb) {
+    var ps = path.join(process.env.SystemRoot, 'System32',
+      'WindowsPowerShell', 'v1.0', 'powershell.exe')
+    var csFile = path.join(__dirname, 'Find-VisualStudio.cs')
+    var psArgs = [
+      '-ExecutionPolicy',
+      'Unrestricted',
+      '-NoProfile',
+      '-Command',
+      '&{Add-Type -Path \'' + csFile + '\';' + '[VisualStudioConfiguration.Main]::PrintJson()}'
+    ]
+
+    this.log.silly('Running', ps, psArgs)
+    var child = execFile(ps, psArgs, { encoding: 'utf8' },
+      (err, stdout, stderr) => {
+        this.parseData(err, stdout, stderr, cb)
+      })
+    child.stdin.end()
+  },
+
+  // Parse the output of the PowerShell script and look for an installation
+  // of Visual Studio 2017 or newer to use
+  parseData: function parseData (err, stdout, stderr, cb) {
+    this.log.silly('PS stderr = %j', stderr)
+
+    const failPowershell = () => {
+      this.addLog(
+        'could not use PowerShell to find Visual Studio 2017 or newer, try re-running with \'--loglevel silly\' for more details')
+      cb(null)
+    }
+
+    if (err) {
+      this.log.silly('PS err = %j', err && (err.stack || err))
+      return failPowershell()
+    }
+
+    var vsInfo
+    try {
+      vsInfo = JSON.parse(stdout)
+    } catch (e) {
+      this.log.silly('PS stdout = %j', stdout)
+      this.log.silly(e)
+      return failPowershell()
+    }
+
+    if (!Array.isArray(vsInfo)) {
+      this.log.silly('PS stdout = %j', stdout)
+      return failPowershell()
+    }
+
+    vsInfo = vsInfo.map((info) => {
+      this.log.silly(`processing installation: "${info.path}"`)
+      info.path = path.resolve(info.path)
+      var ret = this.getVersionInfo(info)
+      ret.path = info.path
+      ret.msBuild = this.getMSBuild(info, ret.versionYear)
+      ret.toolset = this.getToolset(info, ret.versionYear)
+      ret.sdk = this.getSDK(info)
+      return ret
+    })
+    this.log.silly('vsInfo:', vsInfo)
+
+    // Remove future versions or errors parsing version number
+    vsInfo = vsInfo.filter((info) => {
+      if (info.versionYear) {
+        return true
+      }
+      this.addLog(`unknown version "${info.version}" found at "${info.path}"`)
+      return false
+    })
+
+    // Sort to place newer versions first
+    vsInfo.sort((a, b) => b.versionYear - a.versionYear)
+
+    for (var i = 0; i < vsInfo.length; ++i) {
+      const info = vsInfo[i]
+      this.addLog(`checking VS${info.versionYear} (${info.version}) found ` +
+                  `at:\n"${info.path}"`)
+
+      if (info.msBuild) {
+        this.addLog('- found "Visual Studio C++ core features"')
+      } else {
+        this.addLog('- "Visual Studio C++ core features" missing')
+        continue
+      }
+
+      if (info.toolset) {
+        this.addLog(`- found VC++ toolset: ${info.toolset}`)
+      } else {
+        this.addLog('- missing any VC++ toolset')
+        continue
+      }
+
+      if (info.sdk) {
+        this.addLog(`- found Windows SDK: ${info.sdk}`)
+      } else {
+        this.addLog('- missing any Windows SDK')
+        continue
+      }
+
+      if (!this.checkConfigVersion(info.versionYear, info.path)) {
+        continue
+      }
+
+      return cb(info)
+    }
+
+    this.addLog(
+      'could not find a version of Visual Studio 2017 or newer to use')
+    cb(null)
+  },
+
+  // Helper - process version information
+  getVersionInfo: function getVersionInfo (info) {
+    const match = /^(\d+)\.(\d+)\..*/.exec(info.version)
+    if (!match) {
+      this.log.silly('- failed to parse version:', info.version)
+      return {}
+    }
+    this.log.silly('- version match = %j', match)
+    var ret = {
+      version: info.version,
+      versionMajor: parseInt(match[1], 10),
+      versionMinor: parseInt(match[2], 10)
+    }
+    if (ret.versionMajor === 15) {
+      ret.versionYear = 2017
+      return ret
+    }
+    if (ret.versionMajor === 16) {
+      ret.versionYear = 2019
+      return ret
+    }
+    if (ret.versionMajor === 17) {
+      ret.versionYear = 2022
+      return ret
+    }
+    this.log.silly('- unsupported version:', ret.versionMajor)
+    return {}
+  },
+
+  // Helper - process MSBuild information
+  getMSBuild: function getMSBuild (info, versionYear) {
+    const pkg = 'Microsoft.VisualStudio.VC.MSBuild.Base'
+    const msbuildPath = path.join(info.path, 'MSBuild', 'Current', 'Bin', 'MSBuild.exe')
+    if (info.packages.indexOf(pkg) !== -1) {
+      this.log.silly('- found VC.MSBuild.Base')
+      if (versionYear === 2017) {
+        return path.join(info.path, 'MSBuild', '15.0', 'Bin', 'MSBuild.exe')
+      }
+      if (versionYear === 2019) {
+        return msbuildPath
+      }
+    }
+    // visual studio 2022 don't has msbuild pkg
+    if (fs.existsSync(msbuildPath)) {
+      return msbuildPath
+    }
+    return null
+  },
+
+  // Helper - process toolset information
+  getToolset: function getToolset (info, versionYear) {
+    const pkg = 'Microsoft.VisualStudio.Component.VC.Tools.x86.x64'
+    const express = 'Microsoft.VisualStudio.WDExpress'
+
+    if (info.packages.indexOf(pkg) !== -1) {
+      this.log.silly('- found VC.Tools.x86.x64')
+    } else if (info.packages.indexOf(express) !== -1) {
+      this.log.silly('- found Visual Studio Express (looking for toolset)')
+    } else {
+      return null
+    }
+
+    if (versionYear === 2017) {
+      return 'v141'
+    } else if (versionYear === 2019) {
+      return 'v142'
+    } else if (versionYear === 2022) {
+      return 'v143'
+    }
+    this.log.silly('- invalid versionYear:', versionYear)
+    return null
+  },
+
+  // Helper - process Windows SDK information
+  getSDK: function getSDK (info) {
+    const win8SDK = 'Microsoft.VisualStudio.Component.Windows81SDK'
+    const win10SDKPrefix = 'Microsoft.VisualStudio.Component.Windows10SDK.'
+
+    var Win10SDKVer = 0
+    info.packages.forEach((pkg) => {
+      if (!pkg.startsWith(win10SDKPrefix)) {
+        return
+      }
+      const parts = pkg.split('.')
+      if (parts.length > 5 && parts[5] !== 'Desktop') {
+        this.log.silly('- ignoring non-Desktop Win10SDK:', pkg)
+        return
+      }
+      const foundSdkVer = parseInt(parts[4], 10)
+      if (isNaN(foundSdkVer)) {
+        // Microsoft.VisualStudio.Component.Windows10SDK.IpOverUsb
+        this.log.silly('- failed to parse Win10SDK number:', pkg)
+        return
+      }
+      this.log.silly('- found Win10SDK:', foundSdkVer)
+      Win10SDKVer = Math.max(Win10SDKVer, foundSdkVer)
+    })
+
+    if (Win10SDKVer !== 0) {
+      return `10.0.${Win10SDKVer}.0`
+    } else if (info.packages.indexOf(win8SDK) !== -1) {
+      this.log.silly('- found Win8SDK')
+      return '8.1'
+    }
+    return null
+  },
+
+  // Find an installation of Visual Studio 2015 to use
+  findVisualStudio2015: function findVisualStudio2015 (cb) {
+    return this.findOldVS({
+      version: '14.0',
+      versionMajor: 14,
+      versionMinor: 0,
+      versionYear: 2015,
+      toolset: 'v140'
+    }, cb)
+  },
+
+  // Find an installation of Visual Studio 2013 to use
+  findVisualStudio2013: function findVisualStudio2013 (cb) {
+    if (this.nodeSemver.major >= 9) {
+      this.addLog(
+        'not looking for VS2013 as it is only supported up to Node.js 8')
+      return cb(null)
+    }
+    return this.findOldVS({
+      version: '12.0',
+      versionMajor: 12,
+      versionMinor: 0,
+      versionYear: 2013,
+      toolset: 'v120'
+    }, cb)
+  },
+
+  // Helper - common code for VS2013 and VS2015
+  findOldVS: function findOldVS (info, cb) {
+    const regVC7 = ['HKLM\\Software\\Microsoft\\VisualStudio\\SxS\\VC7',
+      'HKLM\\Software\\Wow6432Node\\Microsoft\\VisualStudio\\SxS\\VC7']
+    const regMSBuild = 'HKLM\\Software\\Microsoft\\MSBuild\\ToolsVersions'
+
+    this.addLog(`looking for Visual Studio ${info.versionYear}`)
+    this.regSearchKeys(regVC7, info.version, [], (err, res) => {
+      if (err) {
+        this.addLog('- not found')
+        return cb(null)
+      }
+
+      const vsPath = path.resolve(res, '..')
+      this.addLog(`- found in "${vsPath}"`)
+
+      const msBuildRegOpts = process.arch === 'ia32' ? [] : ['/reg:32']
+      this.regSearchKeys([`${regMSBuild}\\${info.version}`],
+        'MSBuildToolsPath', msBuildRegOpts, (err, res) => {
+          if (err) {
+            this.addLog(
+              '- could not find MSBuild in registry for this version')
+            return cb(null)
+          }
+
+          const msBuild = path.join(res, 'MSBuild.exe')
+          this.addLog(`- MSBuild in "${msBuild}"`)
+
+          if (!this.checkConfigVersion(info.versionYear, vsPath)) {
+            return cb(null)
+          }
+
+          info.path = vsPath
+          info.msBuild = msBuild
+          info.sdk = null
+          cb(info)
+        })
+    })
+  },
+
+  // After finding a usable version of Visual Studio:
+  // - add it to validVersions to be displayed at the end if a specific
+  //   version was requested and not found;
+  // - check if this is the version that was requested.
+  // - check if this matches the Visual Studio Command Prompt
+  checkConfigVersion: function checkConfigVersion (versionYear, vsPath) {
+    this.validVersions.push(versionYear)
+    this.validVersions.push(vsPath)
+
+    if (this.configVersionYear && this.configVersionYear !== versionYear) {
+      this.addLog('- msvs_version does not match this version')
+      return false
+    }
+    if (this.configPath &&
+        path.relative(this.configPath, vsPath) !== '') {
+      this.addLog('- msvs_version does not point to this installation')
+      return false
+    }
+    if (this.envVcInstallDir &&
+        path.relative(this.envVcInstallDir, vsPath) !== '') {
+      this.addLog('- does not match this Visual Studio Command Prompt')
+      return false
+    }
+
+    return true
+  }
+}
+
+module.exports = findVisualStudio
+module.exports.test = {
+  VisualStudioFinder: VisualStudioFinder,
+  findVisualStudio: findVisualStudio
+}
diff --git a/server/node_modules/node-gyp/lib/install.js b/server/node_modules/node-gyp/lib/install.js
new file mode 100644
index 0000000..99f6d85
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/install.js
@@ -0,0 +1,376 @@
+'use strict'
+
+const fs = require('graceful-fs')
+const os = require('os')
+const tar = require('tar')
+const path = require('path')
+const util = require('util')
+const stream = require('stream')
+const crypto = require('crypto')
+const log = require('npmlog')
+const semver = require('semver')
+const fetch = require('make-fetch-happen')
+const processRelease = require('./process-release')
+const win = process.platform === 'win32'
+const streamPipeline = util.promisify(stream.pipeline)
+
+/**
+ * @param {typeof import('graceful-fs')} fs
+ */
+
+async function install (fs, gyp, argv) {
+  const release = processRelease(argv, gyp, process.version, process.release)
+
+  // Determine which node dev files version we are installing
+  log.verbose('install', 'input version string %j', release.version)
+
+  if (!release.semver) {
+    // could not parse the version string with semver
+    throw new Error('Invalid version number: ' + release.version)
+  }
+
+  if (semver.lt(release.version, '0.8.0')) {
+    throw new Error('Minimum target version is `0.8.0` or greater. Got: ' + release.version)
+  }
+
+  // 0.x.y-pre versions are not published yet and cannot be installed. Bail.
+  if (release.semver.prerelease[0] === 'pre') {
+    log.verbose('detected "pre" node version', release.version)
+    if (!gyp.opts.nodedir) {
+      throw new Error('"pre" versions of node cannot be installed, use the --nodedir flag instead')
+    }
+    log.verbose('--nodedir flag was passed; skipping install', gyp.opts.nodedir)
+    return
+  }
+
+  // flatten version into String
+  log.verbose('install', 'installing version: %s', release.versionDir)
+
+  // the directory where the dev files will be installed
+  const devDir = path.resolve(gyp.devDir, release.versionDir)
+
+  // If '--ensure' was passed, then don't *always* install the version;
+  // check if it is already installed, and only install when needed
+  if (gyp.opts.ensure) {
+    log.verbose('install', '--ensure was passed, so won\'t reinstall if already installed')
+    try {
+      await fs.promises.stat(devDir)
+    } catch (err) {
+      if (err.code === 'ENOENT') {
+        log.verbose('install', 'version not already installed, continuing with install', release.version)
+        try {
+          return await go()
+        } catch (err) {
+          return rollback(err)
+        }
+      } else if (err.code === 'EACCES') {
+        return eaccesFallback(err)
+      }
+      throw err
+    }
+    log.verbose('install', 'version is already installed, need to check "installVersion"')
+    const installVersionFile = path.resolve(devDir, 'installVersion')
+    let installVersion = 0
+    try {
+      const ver = await fs.promises.readFile(installVersionFile, 'ascii')
+      installVersion = parseInt(ver, 10) || 0
+    } catch (err) {
+      if (err.code !== 'ENOENT') {
+        throw err
+      }
+    }
+    log.verbose('got "installVersion"', installVersion)
+    log.verbose('needs "installVersion"', gyp.package.installVersion)
+    if (installVersion < gyp.package.installVersion) {
+      log.verbose('install', 'version is no good; reinstalling')
+      try {
+        return await go()
+      } catch (err) {
+        return rollback(err)
+      }
+    }
+    log.verbose('install', 'version is good')
+  } else {
+    try {
+      return await go()
+    } catch (err) {
+      return rollback(err)
+    }
+  }
+
+  async function go () {
+    log.verbose('ensuring nodedir is created', devDir)
+
+    // first create the dir for the node dev files
+    try {
+      const created = await fs.promises.mkdir(devDir, { recursive: true })
+
+      if (created) {
+        log.verbose('created nodedir', created)
+      }
+    } catch (err) {
+      if (err.code === 'EACCES') {
+        return eaccesFallback(err)
+      }
+
+      throw err
+    }
+
+    // now download the node tarball
+    const tarPath = gyp.opts.tarball
+    let extractCount = 0
+    const contentShasums = {}
+    const expectShasums = {}
+
+    // checks if a file to be extracted from the tarball is valid.
+    // only .h header files and the gyp files get extracted
+    function isValid (path) {
+      const isValid = valid(path)
+      if (isValid) {
+        log.verbose('extracted file from tarball', path)
+        extractCount++
+      } else {
+        // invalid
+        log.silly('ignoring from tarball', path)
+      }
+      return isValid
+    }
+
+    // download the tarball and extract!
+
+    if (tarPath) {
+      await tar.extract({
+        file: tarPath,
+        strip: 1,
+        filter: isValid,
+        cwd: devDir
+      })
+    } else {
+      try {
+        const res = await download(gyp, release.tarballUrl)
+
+        if (res.status !== 200) {
+          throw new Error(`${res.status} response downloading ${release.tarballUrl}`)
+        }
+
+        await streamPipeline(
+          res.body,
+          // content checksum
+          new ShaSum((_, checksum) => {
+            const filename = path.basename(release.tarballUrl).trim()
+            contentShasums[filename] = checksum
+            log.verbose('content checksum', filename, checksum)
+          }),
+          tar.extract({
+            strip: 1,
+            cwd: devDir,
+            filter: isValid
+          })
+        )
+      } catch (err) {
+        // something went wrong downloading the tarball?
+        if (err.code === 'ENOTFOUND') {
+          throw new Error('This is most likely not a problem with node-gyp or the package itself and\n' +
+            'is related to network connectivity. In most cases you are behind a proxy or have bad \n' +
+            'network settings.')
+        }
+        throw err
+      }
+    }
+
+    // invoked after the tarball has finished being extracted
+    if (extractCount === 0) {
+      throw new Error('There was a fatal problem while downloading/extracting the tarball')
+    }
+
+    log.verbose('tarball', 'done parsing tarball')
+
+    const installVersionPath = path.resolve(devDir, 'installVersion')
+    await Promise.all([
+      // need to download node.lib
+      ...(win ? downloadNodeLib() : []),
+      // write the "installVersion" file
+      fs.promises.writeFile(installVersionPath, gyp.package.installVersion + '\n'),
+      // Only download SHASUMS.txt if we downloaded something in need of SHA verification
+      ...(!tarPath || win ? [downloadShasums()] : [])
+    ])
+
+    log.verbose('download contents checksum', JSON.stringify(contentShasums))
+    // check content shasums
+    for (const k in contentShasums) {
+      log.verbose('validating download checksum for ' + k, '(%s == %s)', contentShasums[k], expectShasums[k])
+      if (contentShasums[k] !== expectShasums[k]) {
+        throw new Error(k + ' local checksum ' + contentShasums[k] + ' not match remote ' + expectShasums[k])
+      }
+    }
+
+    async function downloadShasums () {
+      log.verbose('check download content checksum, need to download `SHASUMS256.txt`...')
+      log.verbose('checksum url', release.shasumsUrl)
+
+      const res = await download(gyp, release.shasumsUrl)
+
+      if (res.status !== 200) {
+        throw new Error(`${res.status}  status code downloading checksum`)
+      }
+
+      for (const line of (await res.text()).trim().split('\n')) {
+        const items = line.trim().split(/\s+/)
+        if (items.length !== 2) {
+          return
+        }
+
+        // 0035d18e2dcf9aad669b1c7c07319e17abfe3762  ./node-v0.11.4.tar.gz
+        const name = items[1].replace(/^\.\//, '')
+        expectShasums[name] = items[0]
+      }
+
+      log.verbose('checksum data', JSON.stringify(expectShasums))
+    }
+
+    function downloadNodeLib () {
+      log.verbose('on Windows; need to download `' + release.name + '.lib`...')
+      const archs = ['ia32', 'x64', 'arm64']
+      return archs.map(async (arch) => {
+        const dir = path.resolve(devDir, arch)
+        const targetLibPath = path.resolve(dir, release.name + '.lib')
+        const { libUrl, libPath } = release[arch]
+        const name = `${arch} ${release.name}.lib`
+        log.verbose(name, 'dir', dir)
+        log.verbose(name, 'url', libUrl)
+
+        await fs.promises.mkdir(dir, { recursive: true })
+        log.verbose('streaming', name, 'to:', targetLibPath)
+
+        const res = await download(gyp, libUrl)
+
+        if (res.status === 403 || res.status === 404) {
+          if (arch === 'arm64') {
+            // Arm64 is a newer platform on Windows and not all node distributions provide it.
+            log.verbose(`${name} was not found in ${libUrl}`)
+          } else {
+            log.warn(`${name} was not found in ${libUrl}`)
+          }
+          return
+        } else if (res.status !== 200) {
+          throw new Error(`${res.status} status code downloading ${name}`)
+        }
+
+        return streamPipeline(
+          res.body,
+          new ShaSum((_, checksum) => {
+            contentShasums[libPath] = checksum
+            log.verbose('content checksum', libPath, checksum)
+          }),
+          fs.createWriteStream(targetLibPath)
+        )
+      })
+    } // downloadNodeLib()
+  } // go()
+
+  /**
+   * Checks if a given filename is "valid" for this installation.
+   */
+
+  function valid (file) {
+    // header files
+    const extname = path.extname(file)
+    return extname === '.h' || extname === '.gypi'
+  }
+
+  async function rollback (err) {
+    log.warn('install', 'got an error, rolling back install')
+    // roll-back the install if anything went wrong
+    await util.promisify(gyp.commands.remove)([release.versionDir])
+    throw err
+  }
+
+  /**
+   * The EACCES fallback is a workaround for npm's `sudo` behavior, where
+   * it drops the permissions before invoking any child processes (like
+   * node-gyp). So what happens is the "nobody" user doesn't have
+   * permission to create the dev dir. As a fallback, make the tmpdir() be
+   * the dev dir for this installation. This is not ideal, but at least
+   * the compilation will succeed...
+   */
+
+  async function eaccesFallback (err) {
+    const noretry = '--node_gyp_internal_noretry'
+    if (argv.indexOf(noretry) !== -1) {
+      throw err
+    }
+    const tmpdir = os.tmpdir()
+    gyp.devDir = path.resolve(tmpdir, '.node-gyp')
+    let userString = ''
+    try {
+      // os.userInfo can fail on some systems, it's not critical here
+      userString = ` ("${os.userInfo().username}")`
+    } catch (e) {}
+    log.warn('EACCES', 'current user%s does not have permission to access the dev dir "%s"', userString, devDir)
+    log.warn('EACCES', 'attempting to reinstall using temporary dev dir "%s"', gyp.devDir)
+    if (process.cwd() === tmpdir) {
+      log.verbose('tmpdir == cwd', 'automatically will remove dev files after to save disk space')
+      gyp.todo.push({ name: 'remove', args: argv })
+    }
+    return util.promisify(gyp.commands.install)([noretry].concat(argv))
+  }
+}
+
+class ShaSum extends stream.Transform {
+  constructor (callback) {
+    super()
+    this._callback = callback
+    this._digester = crypto.createHash('sha256')
+  }
+
+  _transform (chunk, _, callback) {
+    this._digester.update(chunk)
+    callback(null, chunk)
+  }
+
+  _flush (callback) {
+    this._callback(null, this._digester.digest('hex'))
+    callback()
+  }
+}
+
+async function download (gyp, url) {
+  log.http('GET', url)
+
+  const requestOpts = {
+    headers: {
+      'User-Agent': `node-gyp v${gyp.version} (node ${process.version})`,
+      Connection: 'keep-alive'
+    },
+    proxy: gyp.opts.proxy,
+    noProxy: gyp.opts.noproxy
+  }
+
+  const cafile = gyp.opts.cafile
+  if (cafile) {
+    requestOpts.ca = await readCAFile(cafile)
+  }
+
+  const res = await fetch(url, requestOpts)
+  log.http(res.status, res.url)
+
+  return res
+}
+
+async function readCAFile (filename) {
+  // The CA file can contain multiple certificates so split on certificate
+  // boundaries.  [\S\s]*? is used to match everything including newlines.
+  const ca = await fs.promises.readFile(filename, 'utf8')
+  const re = /(-----BEGIN CERTIFICATE-----[\S\s]*?-----END CERTIFICATE-----)/g
+  return ca.match(re)
+}
+
+module.exports = function (gyp, argv, callback) {
+  install(fs, gyp, argv).then(callback.bind(undefined, null), callback)
+}
+module.exports.test = {
+  download,
+  install,
+  readCAFile
+}
+module.exports.usage = 'Install node development files for the specified node version.'
diff --git a/server/node_modules/node-gyp/lib/list.js b/server/node_modules/node-gyp/lib/list.js
new file mode 100644
index 0000000..405ebc0
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/list.js
@@ -0,0 +1,27 @@
+'use strict'
+
+const fs = require('graceful-fs')
+const log = require('npmlog')
+
+function list (gyp, args, callback) {
+  var devDir = gyp.devDir
+  log.verbose('list', 'using node-gyp dir:', devDir)
+
+  fs.readdir(devDir, onreaddir)
+
+  function onreaddir (err, versions) {
+    if (err && err.code !== 'ENOENT') {
+      return callback(err)
+    }
+
+    if (Array.isArray(versions)) {
+      versions = versions.filter(function (v) { return v !== 'current' })
+    } else {
+      versions = []
+    }
+    callback(null, versions)
+  }
+}
+
+module.exports = list
+module.exports.usage = 'Prints a listing of the currently installed node development files'
diff --git a/server/node_modules/node-gyp/lib/node-gyp.js b/server/node_modules/node-gyp/lib/node-gyp.js
new file mode 100644
index 0000000..0f11185
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/node-gyp.js
@@ -0,0 +1,211 @@
+'use strict'
+
+const path = require('path')
+const nopt = require('nopt')
+const log = require('npmlog')
+const childProcess = require('child_process')
+const EE = require('events').EventEmitter
+const inherits = require('util').inherits
+const commands = [
+  // Module build commands
+  'build',
+  'clean',
+  'configure',
+  'rebuild',
+  // Development Header File management commands
+  'install',
+  'list',
+  'remove'
+]
+const aliases = {
+  ls: 'list',
+  rm: 'remove'
+}
+
+// differentiate node-gyp's logs from npm's
+log.heading = 'gyp'
+
+function gyp () {
+  return new Gyp()
+}
+
+function Gyp () {
+  var self = this
+
+  this.devDir = ''
+  this.commands = {}
+
+  commands.forEach(function (command) {
+    self.commands[command] = function (argv, callback) {
+      log.verbose('command', command, argv)
+      return require('./' + command)(self, argv, callback)
+    }
+  })
+}
+inherits(Gyp, EE)
+exports.Gyp = Gyp
+var proto = Gyp.prototype
+
+/**
+ * Export the contents of the package.json.
+ */
+
+proto.package = require('../package.json')
+
+/**
+ * nopt configuration definitions
+ */
+
+proto.configDefs = {
+  help: Boolean, // everywhere
+  arch: String, // 'configure'
+  cafile: String, // 'install'
+  debug: Boolean, // 'build'
+  directory: String, // bin
+  make: String, // 'build'
+  msvs_version: String, // 'configure'
+  ensure: Boolean, // 'install'
+  solution: String, // 'build' (windows only)
+  proxy: String, // 'install'
+  noproxy: String, // 'install'
+  devdir: String, // everywhere
+  nodedir: String, // 'configure'
+  loglevel: String, // everywhere
+  python: String, // 'configure'
+  'dist-url': String, // 'install'
+  tarball: String, // 'install'
+  jobs: String, // 'build'
+  thin: String, // 'configure'
+  'force-process-config': Boolean // 'configure'
+}
+
+/**
+ * nopt shorthands
+ */
+
+proto.shorthands = {
+  release: '--no-debug',
+  C: '--directory',
+  debug: '--debug',
+  j: '--jobs',
+  silly: '--loglevel=silly',
+  verbose: '--loglevel=verbose',
+  silent: '--loglevel=silent'
+}
+
+/**
+ * expose the command aliases for the bin file to use.
+ */
+
+proto.aliases = aliases
+
+/**
+ * Parses the given argv array and sets the 'opts',
+ * 'argv' and 'command' properties.
+ */
+
+proto.parseArgv = function parseOpts (argv) {
+  this.opts = nopt(this.configDefs, this.shorthands, argv)
+  this.argv = this.opts.argv.remain.slice()
+
+  var commands = this.todo = []
+
+  // create a copy of the argv array with aliases mapped
+  argv = this.argv.map(function (arg) {
+    // is this an alias?
+    if (arg in this.aliases) {
+      arg = this.aliases[arg]
+    }
+    return arg
+  }, this)
+
+  // process the mapped args into "command" objects ("name" and "args" props)
+  argv.slice().forEach(function (arg) {
+    if (arg in this.commands) {
+      var args = argv.splice(0, argv.indexOf(arg))
+      argv.shift()
+      if (commands.length > 0) {
+        commands[commands.length - 1].args = args
+      }
+      commands.push({ name: arg, args: [] })
+    }
+  }, this)
+  if (commands.length > 0) {
+    commands[commands.length - 1].args = argv.splice(0)
+  }
+
+  // support for inheriting config env variables from npm
+  var npmConfigPrefix = 'npm_config_'
+  Object.keys(process.env).forEach(function (name) {
+    if (name.indexOf(npmConfigPrefix) !== 0) {
+      return
+    }
+    var val = process.env[name]
+    if (name === npmConfigPrefix + 'loglevel') {
+      log.level = val
+    } else {
+      // add the user-defined options to the config
+      name = name.substring(npmConfigPrefix.length)
+      // gyp@741b7f1 enters an infinite loop when it encounters
+      // zero-length options so ensure those don't get through.
+      if (name) {
+        this.opts[name] = val
+      }
+    }
+  }, this)
+
+  if (this.opts.loglevel) {
+    log.level = this.opts.loglevel
+  }
+  log.resume()
+}
+
+/**
+ * Spawns a child process and emits a 'spawn' event.
+ */
+
+proto.spawn = function spawn (command, args, opts) {
+  if (!opts) {
+    opts = {}
+  }
+  if (!opts.silent && !opts.stdio) {
+    opts.stdio = [0, 1, 2]
+  }
+  var cp = childProcess.spawn(command, args, opts)
+  log.info('spawn', command)
+  log.info('spawn args', args)
+  return cp
+}
+
+/**
+ * Returns the usage instructions for node-gyp.
+ */
+
+proto.usage = function usage () {
+  var str = [
+    '',
+    '  Usage: node-gyp <command> [options]',
+    '',
+    '  where <command> is one of:',
+    commands.map(function (c) {
+      return '    - ' + c + ' - ' + require('./' + c).usage
+    }).join('\n'),
+    '',
+    'node-gyp@' + this.version + '  ' + path.resolve(__dirname, '..'),
+    'node@' + process.versions.node
+  ].join('\n')
+  return str
+}
+
+/**
+ * Version number getter.
+ */
+
+Object.defineProperty(proto, 'version', {
+  get: function () {
+    return this.package.version
+  },
+  enumerable: true
+})
+
+module.exports = exports = gyp
diff --git a/server/node_modules/node-gyp/lib/process-release.js b/server/node_modules/node-gyp/lib/process-release.js
new file mode 100644
index 0000000..95b55e4
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/process-release.js
@@ -0,0 +1,147 @@
+/* eslint-disable node/no-deprecated-api */
+
+'use strict'
+
+const semver = require('semver')
+const url = require('url')
+const path = require('path')
+const log = require('npmlog')
+
+// versions where -headers.tar.gz started shipping
+const headersTarballRange = '>= 3.0.0 || ~0.12.10 || ~0.10.42'
+const bitsre = /\/win-(x86|x64|arm64)\//
+const bitsreV3 = /\/win-(x86|ia32|x64)\// // io.js v3.x.x shipped with "ia32" but should
+// have been "x86"
+
+// Captures all the logic required to determine download URLs, local directory and
+// file names. Inputs come from command-line switches (--target, --dist-url),
+// `process.version` and `process.release` where it exists.
+function processRelease (argv, gyp, defaultVersion, defaultRelease) {
+  var version = (semver.valid(argv[0]) && argv[0]) || gyp.opts.target || defaultVersion
+  var versionSemver = semver.parse(version)
+  var overrideDistUrl = gyp.opts['dist-url'] || gyp.opts.disturl
+  var isDefaultVersion
+  var isNamedForLegacyIojs
+  var name
+  var distBaseUrl
+  var baseUrl
+  var libUrl32
+  var libUrl64
+  var libUrlArm64
+  var tarballUrl
+  var canGetHeaders
+
+  if (!versionSemver) {
+    // not a valid semver string, nothing we can do
+    return { version: version }
+  }
+  // flatten version into String
+  version = versionSemver.version
+
+  // defaultVersion should come from process.version so ought to be valid semver
+  isDefaultVersion = version === semver.parse(defaultVersion).version
+
+  // can't use process.release if we're using --target=x.y.z
+  if (!isDefaultVersion) {
+    defaultRelease = null
+  }
+
+  if (defaultRelease) {
+    // v3 onward, has process.release
+    name = defaultRelease.name.replace(/io\.js/, 'iojs') // remove the '.' for directory naming purposes
+  } else {
+    // old node or alternative --target=
+    // semver.satisfies() doesn't like prerelease tags so test major directly
+    isNamedForLegacyIojs = versionSemver.major >= 1 && versionSemver.major < 4
+    // isNamedForLegacyIojs is required to support Electron < 4 (in particular Electron 3)
+    // as previously this logic was used to ensure "iojs" was used to download iojs releases
+    // and "node" for node releases.  Unfortunately the logic was broad enough that electron@3
+    // published release assets as "iojs" so that the node-gyp logic worked.  Once Electron@3 has
+    // been EOL for a while (late 2019) we should remove this hack.
+    name = isNamedForLegacyIojs ? 'iojs' : 'node'
+  }
+
+  // check for the nvm.sh standard mirror env variables
+  if (!overrideDistUrl && process.env.NODEJS_ORG_MIRROR) {
+    overrideDistUrl = process.env.NODEJS_ORG_MIRROR
+  }
+
+  if (overrideDistUrl) {
+    log.verbose('download', 'using dist-url', overrideDistUrl)
+  }
+
+  if (overrideDistUrl) {
+    distBaseUrl = overrideDistUrl.replace(/\/+$/, '')
+  } else {
+    distBaseUrl = 'https://nodejs.org/dist'
+  }
+  distBaseUrl += '/v' + version + '/'
+
+  // new style, based on process.release so we have a lot of the data we need
+  if (defaultRelease && defaultRelease.headersUrl && !overrideDistUrl) {
+    baseUrl = url.resolve(defaultRelease.headersUrl, './')
+    libUrl32 = resolveLibUrl(name, defaultRelease.libUrl || baseUrl || distBaseUrl, 'x86', versionSemver.major)
+    libUrl64 = resolveLibUrl(name, defaultRelease.libUrl || baseUrl || distBaseUrl, 'x64', versionSemver.major)
+    libUrlArm64 = resolveLibUrl(name, defaultRelease.libUrl || baseUrl || distBaseUrl, 'arm64', versionSemver.major)
+    tarballUrl = defaultRelease.headersUrl
+  } else {
+    // older versions without process.release are captured here and we have to make
+    // a lot of assumptions, additionally if you --target=x.y.z then we can't use the
+    // current process.release
+    baseUrl = distBaseUrl
+    libUrl32 = resolveLibUrl(name, baseUrl, 'x86', versionSemver.major)
+    libUrl64 = resolveLibUrl(name, baseUrl, 'x64', versionSemver.major)
+    libUrlArm64 = resolveLibUrl(name, baseUrl, 'arm64', versionSemver.major)
+
+    // making the bold assumption that anything with a version number >3.0.0 will
+    // have a *-headers.tar.gz file in its dist location, even some frankenstein
+    // custom version
+    canGetHeaders = semver.satisfies(versionSemver, headersTarballRange)
+    tarballUrl = url.resolve(baseUrl, name + '-v' + version + (canGetHeaders ? '-headers' : '') + '.tar.gz')
+  }
+
+  return {
+    version: version,
+    semver: versionSemver,
+    name: name,
+    baseUrl: baseUrl,
+    tarballUrl: tarballUrl,
+    shasumsUrl: url.resolve(baseUrl, 'SHASUMS256.txt'),
+    versionDir: (name !== 'node' ? name + '-' : '') + version,
+    ia32: {
+      libUrl: libUrl32,
+      libPath: normalizePath(path.relative(url.parse(baseUrl).path, url.parse(libUrl32).path))
+    },
+    x64: {
+      libUrl: libUrl64,
+      libPath: normalizePath(path.relative(url.parse(baseUrl).path, url.parse(libUrl64).path))
+    },
+    arm64: {
+      libUrl: libUrlArm64,
+      libPath: normalizePath(path.relative(url.parse(baseUrl).path, url.parse(libUrlArm64).path))
+    }
+  }
+}
+
+function normalizePath (p) {
+  return path.normalize(p).replace(/\\/g, '/')
+}
+
+function resolveLibUrl (name, defaultUrl, arch, versionMajor) {
+  var base = url.resolve(defaultUrl, './')
+  var hasLibUrl = bitsre.test(defaultUrl) || (versionMajor === 3 && bitsreV3.test(defaultUrl))
+
+  if (!hasLibUrl) {
+    // let's assume it's a baseUrl then
+    if (versionMajor >= 1) {
+      return url.resolve(base, 'win-' + arch + '/' + name + '.lib')
+    }
+    // prior to io.js@1.0.0 32-bit node.lib lives in /, 64-bit lives in /x64/
+    return url.resolve(base, (arch === 'x86' ? '' : arch + '/') + name + '.lib')
+  }
+
+  // else we have a proper url to a .lib, just make sure it's the right arch
+  return defaultUrl.replace(versionMajor === 3 ? bitsreV3 : bitsre, '/win-' + arch + '/')
+}
+
+module.exports = processRelease
diff --git a/server/node_modules/node-gyp/lib/rebuild.js b/server/node_modules/node-gyp/lib/rebuild.js
new file mode 100644
index 0000000..a1c5b27
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/rebuild.js
@@ -0,0 +1,13 @@
+'use strict'
+
+function rebuild (gyp, argv, callback) {
+  gyp.todo.push(
+    { name: 'clean', args: [] }
+    , { name: 'configure', args: argv }
+    , { name: 'build', args: [] }
+  )
+  process.nextTick(callback)
+}
+
+module.exports = rebuild
+module.exports.usage = 'Runs "clean", "configure" and "build" all at once'
diff --git a/server/node_modules/node-gyp/lib/remove.js b/server/node_modules/node-gyp/lib/remove.js
new file mode 100644
index 0000000..8c945e5
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/remove.js
@@ -0,0 +1,46 @@
+'use strict'
+
+const fs = require('fs')
+const rm = require('rimraf')
+const path = require('path')
+const log = require('npmlog')
+const semver = require('semver')
+
+function remove (gyp, argv, callback) {
+  var devDir = gyp.devDir
+  log.verbose('remove', 'using node-gyp dir:', devDir)
+
+  // get the user-specified version to remove
+  var version = argv[0] || gyp.opts.target
+  log.verbose('remove', 'removing target version:', version)
+
+  if (!version) {
+    return callback(new Error('You must specify a version number to remove. Ex: "' + process.version + '"'))
+  }
+
+  var versionSemver = semver.parse(version)
+  if (versionSemver) {
+    // flatten the version Array into a String
+    version = versionSemver.version
+  }
+
+  var versionPath = path.resolve(gyp.devDir, version)
+  log.verbose('remove', 'removing development files for version:', version)
+
+  // first check if its even installed
+  fs.stat(versionPath, function (err) {
+    if (err) {
+      if (err.code === 'ENOENT') {
+        callback(null, 'version was already uninstalled: ' + version)
+      } else {
+        callback(err)
+      }
+      return
+    }
+    // Go ahead and delete the dir
+    rm(versionPath, callback)
+  })
+}
+
+module.exports = exports = remove
+module.exports.usage = 'Removes the node development files for the specified version'
diff --git a/server/node_modules/node-gyp/lib/util.js b/server/node_modules/node-gyp/lib/util.js
new file mode 100644
index 0000000..3e23c62
--- /dev/null
+++ b/server/node_modules/node-gyp/lib/util.js
@@ -0,0 +1,64 @@
+'use strict'
+
+const log = require('npmlog')
+const execFile = require('child_process').execFile
+const path = require('path')
+
+function logWithPrefix (log, prefix) {
+  function setPrefix (logFunction) {
+    return (...args) => logFunction.apply(null, [ prefix, ...args ]) // eslint-disable-line
+  }
+  return {
+    silly: setPrefix(log.silly),
+    verbose: setPrefix(log.verbose),
+    info: setPrefix(log.info),
+    warn: setPrefix(log.warn),
+    error: setPrefix(log.error)
+  }
+}
+
+function regGetValue (key, value, addOpts, cb) {
+  const outReValue = value.replace(/\W/g, '.')
+  const outRe = new RegExp(`^\\s+${outReValue}\\s+REG_\\w+\\s+(\\S.*)$`, 'im')
+  const reg = path.join(process.env.SystemRoot, 'System32', 'reg.exe')
+  const regArgs = ['query', key, '/v', value].concat(addOpts)
+
+  log.silly('reg', 'running', reg, regArgs)
+  const child = execFile(reg, regArgs, { encoding: 'utf8' },
+    function (err, stdout, stderr) {
+      log.silly('reg', 'reg.exe stdout = %j', stdout)
+      if (err || stderr.trim() !== '') {
+        log.silly('reg', 'reg.exe err = %j', err && (err.stack || err))
+        log.silly('reg', 'reg.exe stderr = %j', stderr)
+        return cb(err, stderr)
+      }
+
+      const result = outRe.exec(stdout)
+      if (!result) {
+        log.silly('reg', 'error parsing stdout')
+        return cb(new Error('Could not parse output of reg.exe'))
+      }
+      log.silly('reg', 'found: %j', result[1])
+      cb(null, result[1])
+    })
+  child.stdin.end()
+}
+
+function regSearchKeys (keys, value, addOpts, cb) {
+  var i = 0
+  const search = () => {
+    log.silly('reg-search', 'looking for %j in %j', value, keys[i])
+    regGetValue(keys[i], value, addOpts, (err, res) => {
+      ++i
+      if (err && i < keys.length) { return search() }
+      cb(err, res)
+    })
+  }
+  search()
+}
+
+module.exports = {
+  logWithPrefix: logWithPrefix,
+  regGetValue: regGetValue,
+  regSearchKeys: regSearchKeys
+}
diff --git a/server/node_modules/node-gyp/macOS_Catalina.md b/server/node_modules/node-gyp/macOS_Catalina.md
new file mode 100644
index 0000000..4fe0f29
--- /dev/null
+++ b/server/node_modules/node-gyp/macOS_Catalina.md
@@ -0,0 +1,104 @@
+# Installation notes for macOS Catalina (v10.15)
+
+_This document specifically refers to upgrades from previous versions of macOS to Catalina (10.15). It should be removed from the source repository when Catalina ceases to be the latest macOS version or when future Catalina versions no longer raise these issues._
+
+**Both upgrading to macOS Catalina and running a Software Update in Catalina may cause normal `node-gyp` installations to fail. This might manifest as the following error during `npm install`:**
+
+```console
+gyp: No Xcode or CLT version detected!
+```
+
+## node-gyp v7
+
+The newest release of `node-gyp` should solve this problem. If you are using `node-gyp` directly then you should be able to install v7 and use it as-is.
+
+If you need to use `node-gyp` from within `npm` (e.g. through `npm install`), you will have to install `node-gyp` (either globally with `-g` or to a predictable location) and tell `npm` where the new version is. Either use:
+
+* `npm config set node_gyp <path to node-gyp>`; or
+* run `npm` with an environment variable prefix: `npm_config_node_gyp=<path to node-gyp> npm install`
+
+Where "path to node-gyp" is to the `node-gyp` executable which may be a symlink in your global bin directory (e.g. `/usr/local/bin/node-gyp`), or a path to the `node-gyp` installation directory and the `bin/node-gyp.js` file within it (e.g. `/usr/local/lib/node_modules/node-gyp/bin/node-gyp.js`).
+
+**If you use `npm config set` to change your global `node_gyp` you are responsible for keeping it up to date and can't rely on `npm` to give you a newer version when available.** Use `npm config delete node_gyp` to unset this configuration option.
+
+## Fixing Catalina for older versions of `node-gyp`
+
+### Is my Mac running macOS Catalina?
+Let's first make sure that your Mac is running Catalina:
+```
+% sw_vers
+    ProductName:	Mac OS X
+    ProductVersion:	10.15
+    BuildVersion:	19A602
+```
+If `ProductVersion` is less then `10.15` then this document is not for you. Normal install docs for `node-gyp` on macOS can be found at https://github.com/nodejs/node-gyp#on-macos
+
+
+### The acid test
+To see if `Xcode Command Line Tools` is installed in a way that will work with `node-gyp`, run:
+```
+curl -sL https://github.com/nodejs/node-gyp/raw/master/macOS_Catalina_acid_test.sh | bash
+```
+
+If test succeeded, _you are done_! You should be ready to [install](https://github.com/nodejs/node-gyp#installation) `node-gyp`.
+
+If test failed, there is a problem with your Xcode Command Line Tools installation. [Continue to Solutions](#Solutions).
+
+### Solutions
+There are three ways to install the Xcode libraries `node-gyp` needs on macOS. People running Catalina have had success with some but not others in a way that has been unpredictable.
+
+1. With the full Xcode (~7.6 GB download) from the `App Store` app.
+2. With the _much_ smaller Xcode Command Line Tools via `xcode-select --install`
+3. With the _much_ smaller Xcode Command Line Tools via manual download. **For people running the latest version of Catalina (10.15.2 at the time of this writing), this has worked when the other two solutions haven't.**
+
+### Installing `node-gyp` using the full Xcode
+1. `xcodebuild -version` should show `Xcode 11.1` or later.
+    * If not, then install/upgrade Xcode from the App Store app.
+2. Open the Xcode app and...
+    * Under __Preferences > Locations__ select the tools if their location is empty.
+    * Allow Xcode app to do an essential install of the most recent compiler tools.
+3. Once all installations are _complete_, quit out of Xcode.
+4. `sudo xcodebuild -license accept`  # If you agree with the licensing terms.
+5. `softwareupdate -l`  # No listing is a good sign.
+    * If Xcode or Tools upgrades are listed, use "Software Upgrade" to install them.
+6. `xcode-select -version`  # Should return `xcode-select version 2370` or later.
+7. `xcode-select -print-path`  # Should return `/Applications/Xcode.app/Contents/Developer`
+8. Try the [_acid test_ steps above](#The-acid-test) to see if your Mac is ready.
+9. If the _acid test_ does _not_ pass then...
+10. `sudo xcode-select --reset`  # Enter root password.  No output is normal.
+11. Repeat step 7 above.  Is the path different this time?  Repeat the _acid test_.
+
+### Installing `node-gyp` using the Xcode Command Line Tools via `xcode-select --install`
+1. If the _acid test_ has not succeeded, then try `xcode-select --install`
+2. If the installation command returns `xcode-select: error: command line tools are already installed, use "Software Update" to install updates`, continue to [remove and reinstall](#i-did-all-that-and-the-acid-test-still-does-not-pass--)
+3. Wait until the install process is _complete_.
+4. `softwareupdate -l`  # No listing is a good sign.
+    * If Xcode or Tools upgrades are listed, use "Software Update" to install them.
+5. `xcode-select -version`  # Should return `xcode-select version 2370` or later.
+6. `xcode-select -print-path`  # Should return `/Library/Developer/CommandLineTools`
+7. Try the [_acid test_ steps above](#The-acid-test) to see if your Mac is ready.
+8. If the _acid test_ does _not_ pass then...
+9. `sudo xcode-select --reset`  # Enter root password.  No output is normal.
+10. Repeat step 5 above.  Is the path different this time?  Repeat the _acid test_.
+
+### Installing `node-gyp` using the Xcode Command Line Tools via manual download
+1. Download the appropriate version of the "Command Line Tools for Xcode" for your version of Catalina from <https://developer.apple.com/download/more/>. As of MacOS 10.15.5, that's [Command_Line_Tools_for_Xcode_11.5.dmg](https://download.developer.apple.com/Developer_Tools/Command_Line_Tools_for_Xcode_11.5/Command_Line_Tools_for_Xcode_11.5.dmg)
+2. Install the package.
+3. Run the [_acid test_ steps above](#The-acid-test).
+
+### I did all that and the acid test still does not pass :-(
+1. `sudo rm -rf $(xcode-select -print-path)`  # Enter root password.  No output is normal.
+2. `sudo rm -rf /Library/Developer/CommandLineTools`  # Enter root password.
+3. `sudo xcode-select --reset`
+4. `xcode-select --install`
+5. If the [_acid test_ steps above](#The-acid-test) still does _not_ pass then...
+6. `npm explore npm -g -- npm install node-gyp@latest`
+7. `npm explore npm -g -- npm explore npm-lifecycle -- npm install node-gyp@latest`
+8. If the _acid test_ still does _not_ pass then...
+9. Add a comment to https://github.com/nodejs/node-gyp/issues/1927 so we can improve.
+
+Lessons learned from:
+* https://github.com/nodejs/node-gyp/issues/1779
+* https://github.com/nodejs/node-gyp/issues/1861
+* https://github.com/nodejs/node-gyp/issues/1927 and elsewhere
+* Thanks to @rrrix for discovering Solution 3
diff --git a/server/node_modules/node-gyp/macOS_Catalina_acid_test.sh b/server/node_modules/node-gyp/macOS_Catalina_acid_test.sh
new file mode 100644
index 0000000..e1e9894
--- /dev/null
+++ b/server/node_modules/node-gyp/macOS_Catalina_acid_test.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+
+pkgs=(
+  "com.apple.pkg.DeveloperToolsCLILeo" # standalone
+  "com.apple.pkg.DeveloperToolsCLI"    # from XCode
+  "com.apple.pkg.CLTools_Executables"  # Mavericks
+)
+
+for pkg in "${pkgs[@]}"; do
+  output=$(/usr/sbin/pkgutil --pkg-info "$pkg" 2>/dev/null)
+  if [ "$output" ]; then
+    version=$(echo "$output" | grep 'version' | cut -d' ' -f2)
+    break
+  fi
+done
+
+if [ "$version" ]; then
+  echo "Command Line Tools version: $version"
+else
+  echo >&2 'Command Line Tools not found'
+fi
diff --git a/server/node_modules/node-gyp/package.json b/server/node_modules/node-gyp/package.json
new file mode 100644
index 0000000..fbeae5e
--- /dev/null
+++ b/server/node_modules/node-gyp/package.json
@@ -0,0 +1,50 @@
+{
+  "name": "node-gyp",
+  "description": "Node.js native addon build tool",
+  "license": "MIT",
+  "keywords": [
+    "native",
+    "addon",
+    "module",
+    "c",
+    "c++",
+    "bindings",
+    "gyp"
+  ],
+  "version": "8.4.1",
+  "installVersion": 9,
+  "author": "Nathan Rajlich <nathan@tootallnate.net> (http://tootallnate.net)",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/nodejs/node-gyp.git"
+  },
+  "preferGlobal": true,
+  "bin": "./bin/node-gyp.js",
+  "main": "./lib/node-gyp.js",
+  "dependencies": {
+    "env-paths": "^2.2.0",
+    "glob": "^7.1.4",
+    "graceful-fs": "^4.2.6",
+    "make-fetch-happen": "^9.1.0",
+    "nopt": "^5.0.0",
+    "npmlog": "^6.0.0",
+    "rimraf": "^3.0.2",
+    "semver": "^7.3.5",
+    "tar": "^6.1.2",
+    "which": "^2.0.2"
+  },
+  "engines": {
+    "node": ">= 10.12.0"
+  },
+  "devDependencies": {
+    "bindings": "^1.5.0",
+    "nan": "^2.14.2",
+    "require-inject": "^1.4.4",
+    "standard": "^14.3.4",
+    "tap": "^12.7.0"
+  },
+  "scripts": {
+    "lint": "standard */*.js test/**/*.js",
+    "test": "npm run lint && tap --timeout=120 test/test-*"
+  }
+}
diff --git a/server/node_modules/node-gyp/src/win_delay_load_hook.cc b/server/node_modules/node-gyp/src/win_delay_load_hook.cc
new file mode 100644
index 0000000..169f802
--- /dev/null
+++ b/server/node_modules/node-gyp/src/win_delay_load_hook.cc
@@ -0,0 +1,39 @@
+/*
+ * When this file is linked to a DLL, it sets up a delay-load hook that
+ * intervenes when the DLL is trying to load the host executable
+ * dynamically. Instead of trying to locate the .exe file it'll just
+ * return a handle to the process image.
+ *
+ * This allows compiled addons to work when the host executable is renamed.
+ */
+
+#ifdef _MSC_VER
+
+#pragma managed(push, off)
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+
+#include <windows.h>
+
+#include <delayimp.h>
+#include <string.h>
+
+static FARPROC WINAPI load_exe_hook(unsigned int event, DelayLoadInfo* info) {
+  HMODULE m;
+  if (event != dliNotePreLoadLibrary)
+    return NULL;
+
+  if (_stricmp(info->szDll, HOST_BINARY) != 0)
+    return NULL;
+
+  m = GetModuleHandle(NULL);
+  return (FARPROC) m;
+}
+
+decltype(__pfnDliNotifyHook2) __pfnDliNotifyHook2 = load_exe_hook;
+
+#pragma managed(pop)
+
+#endif
diff --git a/server/node_modules/node-gyp/test/common.js b/server/node_modules/node-gyp/test/common.js
new file mode 100644
index 0000000..b714ee2
--- /dev/null
+++ b/server/node_modules/node-gyp/test/common.js
@@ -0,0 +1,3 @@
+const envPaths = require('env-paths')
+
+module.exports.devDir = () => envPaths('node-gyp', { suffix: '' }).cache
diff --git a/server/node_modules/node-gyp/test/fixtures/VS_2017_BuildTools_minimal.txt b/server/node_modules/node-gyp/test/fixtures/VS_2017_BuildTools_minimal.txt
new file mode 100644
index 0000000..244f6b0
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/VS_2017_BuildTools_minimal.txt
@@ -0,0 +1 @@
+[{"path":"C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\BuildTools","version":"15.9.28307.665","packages":["Microsoft.VisualStudio.Product.BuildTools","Microsoft.VisualStudio.Component.VC.CoreIde","Microsoft.VisualStudio.VC.Ide.Pro","Microsoft.VisualStudio.VC.Ide.Pro.Resources","Microsoft.VisualStudio.VC.Templates.Pro","Microsoft.VisualStudio.VC.Templates.Pro.Resources","Microsoft.VisualStudio.VC.Items.Pro","Microsoft.VisualStudio.PackageGroup.VC.CoreIDE.Reduced","Microsoft.VisualStudio.VC.Ide.MDD","Microsoft.VisualStudio.VC.Ide.x64","Microsoft.VisualStudio.PackageGroup.VC.CoreIDE.Express","Microsoft.VisualStudio.PackageGroup.Debugger.Script","Microsoft.VisualStudio.JavaScript.LanguageService","Microsoft.VisualStudio.JavaScript.LanguageService.Resources","Microsoft.VisualStudio.Debugger.Script.Msi","Microsoft.VisualStudio.Debugger.Script","Microsoft.VisualStudio.Debugger.Script","Microsoft.VisualStudio.Debugger.Script.Resources","Microsoft.VisualStudio.Debugger.Script.Resources","Microsoft.VisualStudio.VC.Ide.WinXPlus","Microsoft.VisualStudio.VC.Ide.Dskx","Microsoft.VisualStudio.VC.Ide.Dskx.Resources","Microsoft.VisualStudio.VC.Ide.Core","Microsoft.VisualStudio.VC.Ide.Core.Resources","Microsoft.VisualStudio.VC.Ide.Base","Microsoft.VisualStudio.VC.Ide.LanguageService","Microsoft.VisualStudio.VC.Ide.ResourceEditor","Microsoft.VisualStudio.VC.Ide.ResourceEditor.Resources","Microsoft.VisualStudio.VC.Ide.ProjectSystem","Microsoft.VisualStudio.VC.Ide.ProjectSystem.Resources","Microsoft.VisualStudio.VC.Ide.Core.VCProjectEngine","Microsoft.VisualStudio.VC.Ide.Core.VCProjectEngine.Resources","Microsoft.VisualStudio.VC.Ide.LanguageService.Resources","Microsoft.VisualStudio.VC.Ide.Base.Resources","Microsoft.VisualStudio.PackageGroup.Core","Microsoft.VisualStudio.TestTools.TeamFoundationClient","Microsoft.VisualStudio.PackageGroup.Debugger.Core","Microsoft.VisualStudio.Debugger.VSCodeDebuggerHost","Microsoft.VisualStudio.VC.Ide.Debugger","Microsoft.VisualStudio.VC.Ide.Debugger.Resources","Microsoft.VisualStudio.VC.Ide.Common","Microsoft.VisualStudio.VC.Ide.Common.Resources","Microsoft.VisualStudio.Debugger.Parallel","Microsoft.VisualStudio.Debugger.Parallel.Resources","Microsoft.VisualStudio.Debugger.CollectionAgents","Microsoft.VisualStudio.Debugger.Managed","Microsoft.CodeAnalysis.VisualStudio.Setup.Resources","Microsoft.CodeAnalysis.VisualStudio.Setup","Microsoft.CodeAnalysis.ExpressionEvaluator.Resources","Microsoft.CodeAnalysis.ExpressionEvaluator","Microsoft.VisualStudio.Debugger.Managed.Resources","Microsoft.VisualStudio.Debugger.Remote","Microsoft.VisualStudio.Debugger.Remote","Microsoft.VisualStudio.Debugger.Remote.Resources","Microsoft.VisualStudio.Debugger.Remote.Resources","Microsoft.VisualStudio.Debugger","Microsoft.VisualStudio.VC.MSVCDis","Microsoft.VisualStudio.ScriptedHost","Microsoft.VisualStudio.ScriptedHost.Targeted","Microsoft.VisualStudio.ScriptedHost.Resources","Microsoft.IntelliTrace.DiagnosticsHub","Microsoft.VisualStudio.Debugger.Resources","Microsoft.PackageGroup.ClientDiagnostics","Microsoft.VisualStudio.AppResponsiveness","Microsoft.VisualStudio.AppResponsiveness.Targeted","Microsoft.VisualStudio.AppResponsiveness.Resources","Microsoft.VisualStudio.ClientDiagnostics","Microsoft.VisualStudio.ClientDiagnostics.Targeted","Microsoft.VisualStudio.ClientDiagnostics.Resources","Microsoft.VisualStudio.PackageGroup.CommunityCore","Microsoft.VisualStudio.ProjectSystem.Full","Microsoft.VisualStudio.ProjectSystem","Microsoft.VisualStudio.Community.x86","Microsoft.VisualStudio.Community.x64","Microsoft.VisualStudio.Community","Microsoft.IntelliTrace.CollectorCab","Microsoft.VisualStudio.Community.Resources","Microsoft.VisualStudio.WebSiteProject.DTE","Microsoft.MSHtml","Microsoft.VisualStudio.Community.Msi.Resources","Microsoft.VisualStudio.Community.Msi","Microsoft.VisualStudio.MinShell.Interop.Msi","Microsoft.VisualStudio.PackageGroup.CoreEditor","PortableFacades","Microsoft.VisualStudio.VirtualTree","Microsoft.VisualStudio.PackageGroup.Progression","Microsoft.VisualStudio.PerformanceProvider","Microsoft.VisualStudio.GraphModel","Microsoft.VisualStudio.GraphProvider","Microsoft.DiaSymReader","Microsoft.VisualStudio.TextMateGrammars","Microsoft.VisualStudio.PackageGroup.TeamExplorer","Microsoft.TeamFoundation.OfficeIntegration","Microsoft.TeamFoundation.OfficeIntegration.Resources","Microsoft.VisualStudio.TeamExplorer","Microsoft.ServiceHub","Microsoft.VisualStudio.ProjectServices","Microsoft.VisualStudio.SLNX.VSIX","Microsoft.VisualStudio.FileHandler.Msi","Microsoft.VisualStudio.FileHandler.Msi","Microsoft.VisualStudio.PackageGroup.MinShell","Microsoft.VisualStudio.MinShell.Msi","Microsoft.VisualStudio.MinShell.Msi.Resources","Microsoft.VisualStudio.MinShell.Interop","Microsoft.VisualStudio.Log","Microsoft.VisualStudio.Log.Targeted","Microsoft.VisualStudio.Log.Resources","Microsoft.VisualStudio.Finalizer","Microsoft.VisualStudio.CoreEditor","Microsoft.VisualStudio.Connected","Microsoft.VisualStudio.Connected.Resources","Microsoft.VisualStudio.MinShell","Microsoft.VisualStudio.MinShell.Platform","Microsoft.VisualStudio.MinShell.Platform.Resources","Microsoft.VisualStudio.MefHosting","Microsoft.VisualStudio.MefHosting.Resources","Microsoft.VisualStudio.Initializer","Microsoft.VisualStudio.ExtensionManager","Microsoft.VisualStudio.Editors","Microsoft.Net.4.TargetingPack","Microsoft.VisualStudio.Component.Windows10SDK.17134","Win10SDK_10.0.17134","Microsoft.VisualStudio.Component.VC.Tools.x86.x64","Microsoft.VisualCpp.CodeAnalysis.Extensions","Microsoft.VisualCpp.CodeAnalysis.Extensions.X86","Microsoft.VisualCpp.CodeAnalysis.ConcurrencyCheck.X86","Microsoft.VisualCpp.CodeAnalysis.ConcurrencyCheck.X86.Resources","Microsoft.VisualCpp.CodeAnalysis.Extensions.X64","Microsoft.VisualCpp.CodeAnalysis.ConcurrencyCheck.X64","Microsoft.VisualCpp.CodeAnalysis.ConcurrencyCheck.X64.Resources","Microsoft.VisualStudio.Component.Static.Analysis.Tools","Microsoft.VisualStudio.StaticAnalysis","Microsoft.VisualStudio.StaticAnalysis.Resources","Microsoft.VisualCpp.Tools.HostX64.TargetX86","Microsoft.VisualCpp.VCTip.HostX64.TargetX86","Microsoft.VisualCpp.Tools.HostX64.TargetX86.Resources","Microsoft.VisualCpp.Tools.HostX64.TargetX64","Microsoft.VisualCpp.VCTip.HostX64.TargetX64","Microsoft.VisualCpp.Tools.HostX64.TargetX64.Resources","Microsoft.VisualCpp.Premium.Tools.HostX86.TargetX64","Microsoft.VisualCpp.Premium.Tools.Hostx86.Targetx64.Resources","Microsoft.VisualCpp.Premium.Tools.HostX86.TargetX86","Microsoft.VisualCpp.Premium.Tools.HostX86.TargetX86.Resources","Microsoft.VisualCpp.Premium.Tools.HostX64.TargetX86","Microsoft.VisualCpp.Premium.Tools.HostX64.TargetX86.Resources","Microsoft.VisualCpp.Premium.Tools.HostX64.TargetX64","Microsoft.VisualCpp.Premium.Tools.HostX64.TargetX64.Resources","Microsoft.VisualCpp.PGO.X86","Microsoft.VisualCpp.PGO.X64","Microsoft.VisualCpp.PGO.Headers","Microsoft.VisualCpp.CRT.x86.Store","Microsoft.VisualCpp.CRT.x86.OneCore.Desktop","Microsoft.VisualCpp.CRT.x64.Store","Microsoft.VisualCpp.CRT.x64.OneCore.Desktop","Microsoft.VisualCpp.CRT.Redist.x86.OneCore.Desktop","Microsoft.VisualCpp.CRT.Redist.x64.OneCore.Desktop","Microsoft.VisualCpp.CRT.ClickOnce.Msi","Microsoft.VisualStudio.PackageGroup.VC.Tools.x86","Microsoft.VisualCpp.Tools.HostX86.TargetX64","Microsoft.VisualCpp.VCTip.hostX86.targetX64","Microsoft.VisualCpp.Tools.Hostx86.Targetx64.Resources","Microsoft.VisualCpp.Tools.HostX86.TargetX86","Microsoft.VisualCpp.VCTip.hostX86.targetX86","Microsoft.VisualCpp.Tools.HostX86.TargetX86.Resources","Microsoft.VisualCpp.Tools.Core.Resources","Microsoft.VisualCpp.Tools.Core.x86","Microsoft.VisualCpp.Tools.Common.Utils","Microsoft.VisualCpp.Tools.Common.Utils.Resources","Microsoft.VisualCpp.DIA.SDK","Microsoft.VisualCpp.CRT.x86.Desktop","Microsoft.VisualCpp.CRT.x64.Desktop","Microsoft.VisualCpp.CRT.Source","Microsoft.VisualCpp.CRT.Redist.X86","Microsoft.VisualCpp.CRT.Redist.X64","Microsoft.VisualCpp.CRT.Redist.Resources","Microsoft.VisualCpp.RuntimeDebug.14","Microsoft.VisualCpp.RuntimeDebug.14","Microsoft.VisualCpp.Redist.14","Microsoft.VisualCpp.Redist.14","Microsoft.VisualCpp.CRT.Headers","Microsoft.VisualStudio.VC.MSBuild.X86","Microsoft.VisualStudio.VC.MSBuild.X64","Microsoft.VS.VC.MSBuild.X64.Resources","Microsoft.VisualStudio.VC.MSBuild.Base","Microsoft.VisualStudio.VC.MSBuild.Base.Resources","Microsoft.VisualStudio.VC.MSBuild.ARM","Microsoft.VisualStudio.Workload.MSBuildTools","Microsoft.VisualStudio.Component.CoreBuildTools","Microsoft.VisualStudio.Setup.Configuration","Microsoft.VisualStudio.PackageGroup.VsDevCmd","Microsoft.VisualStudio.VsDevCmd.Ext.NetFxSdk","Microsoft.VisualStudio.VsDevCmd.Core.WinSdk","Microsoft.VisualStudio.VsDevCmd.Core.DotNet","Microsoft.VisualStudio.VC.DevCmd","Microsoft.VisualStudio.VC.DevCmd.Resources","Microsoft.VisualStudio.BuildTools.Resources","Microsoft.VisualStudio.Net.Eula.Resources","Microsoft.Build.Dependencies","Microsoft.Build.FileTracker.Msi","Microsoft.Component.MSBuild","Microsoft.PythonTools.BuildCore.Vsix","Microsoft.NuGet.Build.Tasks","Microsoft.VisualStudio.Component.Roslyn.Compiler","Microsoft.CodeAnalysis.Compilers.Resources","Microsoft.CodeAnalysis.Compilers","Microsoft.Net.PackageGroup.4.6.1.Redist","Microsoft.VisualStudio.NativeImageSupport","Microsoft.Build"]}]
diff --git a/server/node_modules/node-gyp/test/fixtures/VS_2017_Community_workload.txt b/server/node_modules/node-gyp/test/fixtures/VS_2017_Community_workload.txt
new file mode 100644
index 0000000..dd5e77d
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/VS_2017_Community_workload.txt
@@ -0,0 +1 @@
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diff --git a/server/node_modules/node-gyp/test/fixtures/VS_2017_Express.txt b/server/node_modules/node-gyp/test/fixtures/VS_2017_Express.txt
new file mode 100644
index 0000000..c4b3b5f
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/VS_2017_Express.txt
@@ -0,0 +1 @@
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diff --git a/server/node_modules/node-gyp/test/fixtures/VS_2017_Unusable.txt b/server/node_modules/node-gyp/test/fixtures/VS_2017_Unusable.txt
new file mode 100644
index 0000000..fc0a257
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/VS_2017_Unusable.txt
@@ -0,0 +1 @@
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diff --git a/server/node_modules/node-gyp/test/fixtures/VS_2019_BuildTools_minimal.txt b/server/node_modules/node-gyp/test/fixtures/VS_2019_BuildTools_minimal.txt
new file mode 100644
index 0000000..f07d254
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/VS_2019_BuildTools_minimal.txt
@@ -0,0 +1 @@
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diff --git a/server/node_modules/node-gyp/test/fixtures/VS_2019_Community_workload.txt b/server/node_modules/node-gyp/test/fixtures/VS_2019_Community_workload.txt
new file mode 100644
index 0000000..50071c2
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/VS_2019_Community_workload.txt
@@ -0,0 +1 @@
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diff --git a/server/node_modules/node-gyp/test/fixtures/VS_2019_Preview.txt b/server/node_modules/node-gyp/test/fixtures/VS_2019_Preview.txt
new file mode 100644
index 0000000..806509e
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/VS_2019_Preview.txt
@@ -0,0 +1 @@
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diff --git a/server/node_modules/node-gyp/test/fixtures/ca-bundle.crt b/server/node_modules/node-gyp/test/fixtures/ca-bundle.crt
new file mode 100644
index 0000000..fb1dea9
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/ca-bundle.crt
@@ -0,0 +1,40 @@
+-----BEGIN CERTIFICATE-----
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+na4fY1gf3zTHxH8259b/TOOaPfTnCEsOQtjUrWNR4xhmVZ+HJy4yytUW
+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----
+MIIDbzCCAlcCAmm6MA0GCSqGSIb3DQEBCwUAMH0xCzAJBgNVBAYTAlVTMQswCQYD
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+uGZtfEvhbNm6m2i4UNmpCXxUZQ==
+-----END CERTIFICATE-----
diff --git a/server/node_modules/node-gyp/test/fixtures/ca.crt b/server/node_modules/node-gyp/test/fixtures/ca.crt
new file mode 100644
index 0000000..aaf9757
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/ca.crt
@@ -0,0 +1,21 @@
+-----BEGIN CERTIFICATE-----
+MIIDZDCCAkwCCQCAzfCLqrJvuTANBgkqhkiG9w0BAQsFADB0MQswCQYDVQQGEwJV
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+rceJuGsnJEQ=
+-----END CERTIFICATE-----
diff --git a/server/node_modules/node-gyp/test/fixtures/nodedir/include/node/config.gypi b/server/node_modules/node-gyp/test/fixtures/nodedir/include/node/config.gypi
new file mode 100644
index 0000000..e767534
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/nodedir/include/node/config.gypi
@@ -0,0 +1,6 @@
+# Test configuration
+{
+  'variables': {
+    'build_with_electron': true
+  }
+}
diff --git a/server/node_modules/node-gyp/test/fixtures/server.crt b/server/node_modules/node-gyp/test/fixtures/server.crt
new file mode 100644
index 0000000..5d0c440
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/server.crt
@@ -0,0 +1,21 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/server/node_modules/node-gyp/test/fixtures/server.key b/server/node_modules/node-gyp/test/fixtures/server.key
new file mode 100644
index 0000000..a844739
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/server.key
@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
diff --git a/server/node_modules/node-gyp/test/fixtures/test-charmap.py b/server/node_modules/node-gyp/test/fixtures/test-charmap.py
new file mode 100644
index 0000000..63aa77b
--- /dev/null
+++ b/server/node_modules/node-gyp/test/fixtures/test-charmap.py
@@ -0,0 +1,31 @@
+import sys
+import locale
+
+try:
+    reload(sys)
+except NameError:  # Python 3
+    pass
+
+
+def main():
+    encoding = locale.getdefaultlocale()[1]
+    if not encoding:
+        return False
+
+    try:
+        sys.setdefaultencoding(encoding)
+    except AttributeError:  # Python 3
+        pass
+
+    textmap = {
+        "cp936": "\u4e2d\u6587",
+        "cp1252": "Lat\u012Bna",
+        "cp932": "\u306b\u307b\u3093\u3054",
+    }
+    if encoding in textmap:
+        print(textmap[encoding])
+    return True
+
+
+if __name__ == "__main__":
+    print(main())
diff --git a/server/node_modules/node-gyp/test/process-exec-sync.js b/server/node_modules/node-gyp/test/process-exec-sync.js
new file mode 100644
index 0000000..21763bc
--- /dev/null
+++ b/server/node_modules/node-gyp/test/process-exec-sync.js
@@ -0,0 +1,140 @@
+'use strict'
+
+const fs = require('graceful-fs')
+const childProcess = require('child_process')
+
+function startsWith (str, search, pos) {
+  if (String.prototype.startsWith) {
+    return str.startsWith(search, pos)
+  }
+
+  return str.substr(!pos || pos < 0 ? 0 : +pos, search.length) === search
+}
+
+function processExecSync (file, args, options) {
+  var child, error, timeout, tmpdir, command
+  command = makeCommand(file, args)
+
+  /*
+    this function emulates child_process.execSync for legacy node <= 0.10.x
+    derived from https://github.com/gvarsanyi/sync-exec/blob/master/js/sync-exec.js
+  */
+
+  options = options || {}
+  // init timeout
+  timeout = Date.now() + options.timeout
+  // init tmpdir
+  var osTempBase = '/tmp'
+  var os = determineOS()
+  osTempBase = '/tmp'
+
+  if (process.env.TMP) {
+    osTempBase = process.env.TMP
+  }
+
+  if (osTempBase[osTempBase.length - 1] !== '/') {
+    osTempBase += '/'
+  }
+
+  tmpdir = osTempBase + 'processExecSync.' + Date.now() + Math.random()
+  fs.mkdirSync(tmpdir)
+
+  // init command
+  if (os === 'linux') {
+    command = '(' + command + ' > ' + tmpdir + '/stdout 2> ' + tmpdir +
+      '/stderr); echo $? > ' + tmpdir + '/status'
+  } else {
+    command = '(' + command + ' > ' + tmpdir + '/stdout 2> ' + tmpdir +
+      '/stderr) | echo %errorlevel% > ' + tmpdir + '/status | exit'
+  }
+
+  // init child
+  child = childProcess.exec(command, options)
+
+  var maxTry = 100000 // increases the test time by 6 seconds on win-2016-node-0.10
+  var tryCount = 0
+  while (tryCount < maxTry) {
+    try {
+      var x = fs.readFileSync(tmpdir + '/status')
+      if (x.toString() === '0') {
+        break
+      }
+    } catch (ignore) {}
+    tryCount++
+    if (Date.now() > timeout) {
+      error = child
+      break
+    }
+  }
+
+  ['stdout', 'stderr', 'status'].forEach(function (file) {
+    child[file] = fs.readFileSync(tmpdir + '/' + file, options.encoding)
+    setTimeout(unlinkFile, 500, tmpdir + '/' + file)
+  })
+
+  child.status = Number(child.status)
+  if (child.status !== 0) {
+    error = child
+  }
+
+  try {
+    fs.rmdirSync(tmpdir)
+  } catch (ignore) {}
+  if (error) {
+    throw error
+  }
+  return child.stdout
+}
+
+function makeCommand (file, args) {
+  var command, quote
+  command = file
+  if (args.length > 0) {
+    for (var i in args) {
+      command = command + ' '
+      if (args[i][0] === '-') {
+        command = command + args[i]
+      } else {
+        if (!quote) {
+          command = command + '"'
+          quote = true
+        }
+        command = command + args[i]
+        if (quote) {
+          if (args.length === (parseInt(i) + 1)) {
+            command = command + '"'
+          }
+        }
+      }
+    }
+  }
+  return command
+}
+
+function determineOS () {
+  var os = ''
+  var tmpVar = ''
+  if (process.env.OSTYPE) {
+    tmpVar = process.env.OSTYPE
+  } else if (process.env.OS) {
+    tmpVar = process.env.OS
+  } else {
+    // default is linux
+    tmpVar = 'linux'
+  }
+
+  if (startsWith(tmpVar, 'linux')) {
+    os = 'linux'
+  }
+  if (startsWith(tmpVar, 'win')) {
+    os = 'win'
+  }
+
+  return os
+}
+
+function unlinkFile (file) {
+  fs.unlinkSync(file)
+}
+
+module.exports = processExecSync
diff --git a/server/node_modules/node-gyp/test/simple-proxy.js b/server/node_modules/node-gyp/test/simple-proxy.js
new file mode 100644
index 0000000..cb0dfcf
--- /dev/null
+++ b/server/node_modules/node-gyp/test/simple-proxy.js
@@ -0,0 +1,27 @@
+'use strict'
+
+const http = require('http')
+const https = require('https')
+const server = http.createServer(handler)
+const port = +process.argv[2]
+const prefix = process.argv[3]
+const upstream = process.argv[4]
+var calls = 0
+
+server.listen(port)
+
+function handler (req, res) {
+  if (req.url.indexOf(prefix) !== 0) {
+    throw new Error('request url [' + req.url + '] does not start with [' + prefix + ']')
+  }
+
+  var upstreamUrl = upstream + req.url.substring(prefix.length)
+  https.get(upstreamUrl, function (ures) {
+    ures.on('end', function () {
+      if (++calls === 2) {
+        server.close()
+      }
+    })
+    ures.pipe(res)
+  })
+}
diff --git a/server/node_modules/node-gyp/test/test-addon.js b/server/node_modules/node-gyp/test/test-addon.js
new file mode 100644
index 0000000..f79eff7
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-addon.js
@@ -0,0 +1,150 @@
+'use strict'
+
+const test = require('tap').test
+const path = require('path')
+const fs = require('graceful-fs')
+const childProcess = require('child_process')
+const os = require('os')
+const addonPath = path.resolve(__dirname, 'node_modules', 'hello_world')
+const nodeGyp = path.resolve(__dirname, '..', 'bin', 'node-gyp.js')
+const execFileSync = childProcess.execFileSync || require('./process-exec-sync')
+const execFile = childProcess.execFile
+
+function runHello (hostProcess) {
+  if (!hostProcess) {
+    hostProcess = process.execPath
+  }
+  var testCode = "console.log(require('hello_world').hello())"
+  return execFileSync(hostProcess, ['-e', testCode], { cwd: __dirname }).toString()
+}
+
+function getEncoding () {
+  var code = 'import locale;print(locale.getdefaultlocale()[1])'
+  return execFileSync('python', ['-c', code]).toString().trim()
+}
+
+function checkCharmapValid () {
+  var data
+  try {
+    data = execFileSync('python', ['fixtures/test-charmap.py'],
+      { cwd: __dirname })
+  } catch (err) {
+    return false
+  }
+  var lines = data.toString().trim().split('\n')
+  return lines.pop() === 'True'
+}
+
+test('build simple addon', function (t) {
+  t.plan(3)
+
+  // Set the loglevel otherwise the output disappears when run via 'npm test'
+  var cmd = [nodeGyp, 'rebuild', '-C', addonPath, '--loglevel=verbose']
+  var proc = execFile(process.execPath, cmd, function (err, stdout, stderr) {
+    var logLines = stderr.toString().trim().split(/\r?\n/)
+    var lastLine = logLines[logLines.length - 1]
+    t.strictEqual(err, null)
+    t.strictEqual(lastLine, 'gyp info ok', 'should end in ok')
+    t.strictEqual(runHello().trim(), 'world')
+  })
+  proc.stdout.setEncoding('utf-8')
+  proc.stderr.setEncoding('utf-8')
+})
+
+test('build simple addon in path with non-ascii characters', function (t) {
+  t.plan(1)
+
+  if (!checkCharmapValid()) {
+    return t.skip('python console app can\'t encode non-ascii character.')
+  }
+
+  var testDirNames = {
+    cp936: '文件夹',
+    cp1252: 'Latīna',
+    cp932: 'フォルダ'
+  }
+  // Select non-ascii characters by current encoding
+  var testDirName = testDirNames[getEncoding()]
+  // If encoding is UTF-8 or other then no need to test
+  if (!testDirName) {
+    return t.skip('no need to test')
+  }
+
+  t.plan(3)
+
+  var data
+  var configPath = path.join(addonPath, 'build', 'config.gypi')
+  try {
+    data = fs.readFileSync(configPath, 'utf8')
+  } catch (err) {
+    t.error(err)
+    return
+  }
+  var config = JSON.parse(data.replace(/#.+\n/, ''))
+  var nodeDir = config.variables.nodedir
+  var testNodeDir = path.join(addonPath, testDirName)
+  // Create symbol link to path with non-ascii characters
+  try {
+    fs.symlinkSync(nodeDir, testNodeDir, 'dir')
+  } catch (err) {
+    switch (err.code) {
+      case 'EEXIST': break
+      case 'EPERM':
+        t.error(err, 'Please try to running console as an administrator')
+        return
+      default:
+        t.error(err)
+        return
+    }
+  }
+
+  var cmd = [
+    nodeGyp,
+    'rebuild',
+    '-C',
+    addonPath,
+    '--loglevel=verbose',
+    '-nodedir=' + testNodeDir
+  ]
+  var proc = execFile(process.execPath, cmd, function (err, stdout, stderr) {
+    try {
+      fs.unlink(testNodeDir)
+    } catch (err) {
+      t.error(err)
+    }
+
+    var logLines = stderr.toString().trim().split(/\r?\n/)
+    var lastLine = logLines[logLines.length - 1]
+    t.strictEqual(err, null)
+    t.strictEqual(lastLine, 'gyp info ok', 'should end in ok')
+    t.strictEqual(runHello().trim(), 'world')
+  })
+  proc.stdout.setEncoding('utf-8')
+  proc.stderr.setEncoding('utf-8')
+})
+
+test('addon works with renamed host executable', function (t) {
+  // No `fs.copyFileSync` before node8.
+  if (process.version.substr(1).split('.')[0] < 8) {
+    t.skip('skipping test for old node version')
+    t.end()
+    return
+  }
+
+  t.plan(3)
+
+  var notNodePath = path.join(os.tmpdir(), 'notnode' + path.extname(process.execPath))
+  fs.copyFileSync(process.execPath, notNodePath)
+
+  var cmd = [nodeGyp, 'rebuild', '-C', addonPath, '--loglevel=verbose']
+  var proc = execFile(process.execPath, cmd, function (err, stdout, stderr) {
+    var logLines = stderr.toString().trim().split(/\r?\n/)
+    var lastLine = logLines[logLines.length - 1]
+    t.strictEqual(err, null)
+    t.strictEqual(lastLine, 'gyp info ok', 'should end in ok')
+    t.strictEqual(runHello(notNodePath).trim(), 'world')
+    fs.unlinkSync(notNodePath)
+  })
+  proc.stdout.setEncoding('utf-8')
+  proc.stderr.setEncoding('utf-8')
+})
diff --git a/server/node_modules/node-gyp/test/test-configure-python.js b/server/node_modules/node-gyp/test/test-configure-python.js
new file mode 100644
index 0000000..4290e7a
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-configure-python.js
@@ -0,0 +1,82 @@
+'use strict'
+
+const test = require('tap').test
+const path = require('path')
+const devDir = require('./common').devDir()
+const gyp = require('../lib/node-gyp')
+const requireInject = require('require-inject')
+const configure = requireInject('../lib/configure', {
+  'graceful-fs': {
+    openSync: function () { return 0 },
+    closeSync: function () { },
+    writeFile: function (file, data, cb) { cb() },
+    stat: function (file, cb) { cb(null, {}) },
+    mkdir: function (dir, options, cb) { cb() },
+    promises: {
+      writeFile: function (file, data) { return Promise.resolve(null) }
+    }
+  }
+})
+
+const EXPECTED_PYPATH = path.join(__dirname, '..', 'gyp', 'pylib')
+const SEPARATOR = process.platform === 'win32' ? ';' : ':'
+const SPAWN_RESULT = { on: function () { } }
+
+require('npmlog').level = 'warn'
+
+test('configure PYTHONPATH with no existing env', function (t) {
+  t.plan(1)
+
+  delete process.env.PYTHONPATH
+
+  var prog = gyp()
+  prog.parseArgv([])
+  prog.spawn = function () {
+    t.equal(process.env.PYTHONPATH, EXPECTED_PYPATH)
+    return SPAWN_RESULT
+  }
+  prog.devDir = devDir
+  configure(prog, [], t.fail)
+})
+
+test('configure PYTHONPATH with existing env of one dir', function (t) {
+  t.plan(2)
+
+  var existingPath = path.join('a', 'b')
+  process.env.PYTHONPATH = existingPath
+
+  var prog = gyp()
+  prog.parseArgv([])
+  prog.spawn = function () {
+    t.equal(process.env.PYTHONPATH, [EXPECTED_PYPATH, existingPath].join(SEPARATOR))
+
+    var dirs = process.env.PYTHONPATH.split(SEPARATOR)
+    t.deepEqual(dirs, [EXPECTED_PYPATH, existingPath])
+
+    return SPAWN_RESULT
+  }
+  prog.devDir = devDir
+  configure(prog, [], t.fail)
+})
+
+test('configure PYTHONPATH with existing env of multiple dirs', function (t) {
+  t.plan(2)
+
+  var pythonDir1 = path.join('a', 'b')
+  var pythonDir2 = path.join('b', 'c')
+  var existingPath = [pythonDir1, pythonDir2].join(SEPARATOR)
+  process.env.PYTHONPATH = existingPath
+
+  var prog = gyp()
+  prog.parseArgv([])
+  prog.spawn = function () {
+    t.equal(process.env.PYTHONPATH, [EXPECTED_PYPATH, existingPath].join(SEPARATOR))
+
+    var dirs = process.env.PYTHONPATH.split(SEPARATOR)
+    t.deepEqual(dirs, [EXPECTED_PYPATH, pythonDir1, pythonDir2])
+
+    return SPAWN_RESULT
+  }
+  prog.devDir = devDir
+  configure(prog, [], t.fail)
+})
diff --git a/server/node_modules/node-gyp/test/test-create-config-gypi.js b/server/node_modules/node-gyp/test/test-create-config-gypi.js
new file mode 100644
index 0000000..eeac73f
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-create-config-gypi.js
@@ -0,0 +1,70 @@
+'use strict'
+
+const path = require('path')
+const { test } = require('tap')
+const gyp = require('../lib/node-gyp')
+const createConfigGypi = require('../lib/create-config-gypi')
+const { parseConfigGypi, getCurrentConfigGypi } = createConfigGypi.test
+
+test('config.gypi with no options', async function (t) {
+  t.plan(2)
+
+  const prog = gyp()
+  prog.parseArgv([])
+
+  const config = await getCurrentConfigGypi({ gyp: prog, vsInfo: {} })
+  t.equal(config.target_defaults.default_configuration, 'Release')
+  t.equal(config.variables.target_arch, process.arch)
+})
+
+test('config.gypi with --debug', async function (t) {
+  t.plan(1)
+
+  const prog = gyp()
+  prog.parseArgv(['_', '_', '--debug'])
+
+  const config = await getCurrentConfigGypi({ gyp: prog, vsInfo: {} })
+  t.equal(config.target_defaults.default_configuration, 'Debug')
+})
+
+test('config.gypi with custom options', async function (t) {
+  t.plan(1)
+
+  const prog = gyp()
+  prog.parseArgv(['_', '_', '--shared-libxml2'])
+
+  const config = await getCurrentConfigGypi({ gyp: prog, vsInfo: {} })
+  t.equal(config.variables.shared_libxml2, true)
+})
+
+test('config.gypi with nodedir', async function (t) {
+  t.plan(1)
+
+  const nodeDir = path.join(__dirname, 'fixtures', 'nodedir')
+
+  const prog = gyp()
+  prog.parseArgv(['_', '_', `--nodedir=${nodeDir}`])
+
+  const config = await getCurrentConfigGypi({ gyp: prog, nodeDir, vsInfo: {} })
+  t.equal(config.variables.build_with_electron, true)
+})
+
+test('config.gypi with --force-process-config', async function (t) {
+  t.plan(1)
+
+  const nodeDir = path.join(__dirname, 'fixtures', 'nodedir')
+
+  const prog = gyp()
+  prog.parseArgv(['_', '_', '--force-process-config', `--nodedir=${nodeDir}`])
+
+  const config = await getCurrentConfigGypi({ gyp: prog, nodeDir, vsInfo: {} })
+  t.equal(config.variables.build_with_electron, undefined)
+})
+
+test('config.gypi parsing', function (t) {
+  t.plan(1)
+
+  const str = "# Some comments\n{'variables': {'multiline': 'A'\n'B'}}"
+  const config = parseConfigGypi(str)
+  t.deepEqual(config, { variables: { multiline: 'AB' } })
+})
diff --git a/server/node_modules/node-gyp/test/test-download.js b/server/node_modules/node-gyp/test/test-download.js
new file mode 100644
index 0000000..71a3c0d
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-download.js
@@ -0,0 +1,207 @@
+'use strict'
+
+const { test } = require('tap')
+const fs = require('fs')
+const path = require('path')
+const util = require('util')
+const http = require('http')
+const https = require('https')
+const install = require('../lib/install')
+const semver = require('semver')
+const devDir = require('./common').devDir()
+const rimraf = require('rimraf')
+const gyp = require('../lib/node-gyp')
+const log = require('npmlog')
+
+log.level = 'warn'
+
+test('download over http', async (t) => {
+  t.plan(2)
+
+  const server = http.createServer((req, res) => {
+    t.strictEqual(req.headers['user-agent'], `node-gyp v42 (node ${process.version})`)
+    res.end('ok')
+  })
+
+  t.tearDown(() => new Promise((resolve) => server.close(resolve)))
+
+  const host = 'localhost'
+  await new Promise((resolve) => server.listen(0, host, resolve))
+  const { port } = server.address()
+  const gyp = {
+    opts: {},
+    version: '42'
+  }
+  const url = `http://${host}:${port}`
+  const res = await install.test.download(gyp, url)
+  t.strictEqual(await res.text(), 'ok')
+})
+
+test('download over https with custom ca', async (t) => {
+  t.plan(3)
+
+  const cafile = path.join(__dirname, '/fixtures/ca.crt')
+  const [cert, key, ca] = await Promise.all([
+    fs.promises.readFile(path.join(__dirname, 'fixtures/server.crt'), 'utf8'),
+    fs.promises.readFile(path.join(__dirname, 'fixtures/server.key'), 'utf8'),
+    install.test.readCAFile(cafile)
+  ])
+
+  t.strictEqual(ca.length, 1)
+
+  const options = { ca: ca, cert: cert, key: key }
+  const server = https.createServer(options, (req, res) => {
+    t.strictEqual(req.headers['user-agent'], `node-gyp v42 (node ${process.version})`)
+    res.end('ok')
+  })
+
+  t.tearDown(() => new Promise((resolve) => server.close(resolve)))
+
+  server.on('clientError', (err) => { throw err })
+
+  const host = 'localhost'
+  await new Promise((resolve) => server.listen(0, host, resolve))
+  const { port } = server.address()
+  const gyp = {
+    opts: { cafile },
+    version: '42'
+  }
+  const url = `https://${host}:${port}`
+  const res = await install.test.download(gyp, url)
+  t.strictEqual(await res.text(), 'ok')
+})
+
+test('download over http with proxy', async (t) => {
+  t.plan(2)
+
+  const server = http.createServer((_, res) => {
+    res.end('ok')
+  })
+
+  const pserver = http.createServer((req, res) => {
+    t.strictEqual(req.headers['user-agent'], `node-gyp v42 (node ${process.version})`)
+    res.end('proxy ok')
+  })
+
+  t.tearDown(() => Promise.all([
+    new Promise((resolve) => server.close(resolve)),
+    new Promise((resolve) => pserver.close(resolve))
+  ]))
+
+  const host = 'localhost'
+  await new Promise((resolve) => server.listen(0, host, resolve))
+  const { port } = server.address()
+  await new Promise((resolve) => pserver.listen(port + 1, host, resolve))
+  const gyp = {
+    opts: {
+      proxy: `http://${host}:${port + 1}`,
+      noproxy: 'bad'
+    },
+    version: '42'
+  }
+  const url = `http://${host}:${port}`
+  const res = await install.test.download(gyp, url)
+  t.strictEqual(await res.text(), 'proxy ok')
+})
+
+test('download over http with noproxy', async (t) => {
+  t.plan(2)
+
+  const server = http.createServer((req, res) => {
+    t.strictEqual(req.headers['user-agent'], `node-gyp v42 (node ${process.version})`)
+    res.end('ok')
+  })
+
+  const pserver = http.createServer((_, res) => {
+    res.end('proxy ok')
+  })
+
+  t.tearDown(() => Promise.all([
+    new Promise((resolve) => server.close(resolve)),
+    new Promise((resolve) => pserver.close(resolve))
+  ]))
+
+  const host = 'localhost'
+  await new Promise((resolve) => server.listen(0, host, resolve))
+  const { port } = server.address()
+  await new Promise((resolve) => pserver.listen(port + 1, host, resolve))
+  const gyp = {
+    opts: {
+      proxy: `http://${host}:${port + 1}`,
+      noproxy: host
+    },
+    version: '42'
+  }
+  const url = `http://${host}:${port}`
+  const res = await install.test.download(gyp, url)
+  t.strictEqual(await res.text(), 'ok')
+})
+
+test('download with missing cafile', async (t) => {
+  t.plan(1)
+  const gyp = {
+    opts: { cafile: 'no.such.file' }
+  }
+  try {
+    await install.test.download(gyp, {}, 'http://bad/')
+  } catch (e) {
+    t.ok(/no.such.file/.test(e.message))
+  }
+})
+
+test('check certificate splitting', async (t) => {
+  const cas = await install.test.readCAFile(path.join(__dirname, 'fixtures/ca-bundle.crt'))
+  t.plan(2)
+  t.strictEqual(cas.length, 2)
+  t.notStrictEqual(cas[0], cas[1])
+})
+
+// only run this test if we are running a version of Node with predictable version path behavior
+
+test('download headers (actual)', async (t) => {
+  if (process.env.FAST_TEST ||
+      process.release.name !== 'node' ||
+      semver.prerelease(process.version) !== null ||
+      semver.satisfies(process.version, '<10')) {
+    return t.skip('Skipping actual download of headers due to test environment configuration')
+  }
+
+  t.plan(12)
+
+  const expectedDir = path.join(devDir, process.version.replace(/^v/, ''))
+  await util.promisify(rimraf)(expectedDir)
+
+  const prog = gyp()
+  prog.parseArgv([])
+  prog.devDir = devDir
+  log.level = 'warn'
+  await util.promisify(install)(prog, [])
+
+  const data = await fs.promises.readFile(path.join(expectedDir, 'installVersion'), 'utf8')
+  t.strictEqual(data, '9\n', 'correct installVersion')
+
+  const list = await fs.promises.readdir(path.join(expectedDir, 'include/node'))
+  t.ok(list.includes('common.gypi'))
+  t.ok(list.includes('config.gypi'))
+  t.ok(list.includes('node.h'))
+  t.ok(list.includes('node_version.h'))
+  t.ok(list.includes('openssl'))
+  t.ok(list.includes('uv'))
+  t.ok(list.includes('uv.h'))
+  t.ok(list.includes('v8-platform.h'))
+  t.ok(list.includes('v8.h'))
+  t.ok(list.includes('zlib.h'))
+
+  const lines = (await fs.promises.readFile(path.join(expectedDir, 'include/node/node_version.h'), 'utf8')).split('\n')
+
+  // extract the 3 version parts from the defines to build a valid version string and
+  // and check them against our current env version
+  const version = ['major', 'minor', 'patch'].reduce((version, type) => {
+    const re = new RegExp(`^#define\\sNODE_${type.toUpperCase()}_VERSION`)
+    const line = lines.find((l) => re.test(l))
+    const i = line ? parseInt(line.replace(/^[^0-9]+([0-9]+).*$/, '$1'), 10) : 'ERROR'
+    return `${version}${type !== 'major' ? '.' : 'v'}${i}`
+  }, '')
+
+  t.strictEqual(version, process.version)
+})
diff --git a/server/node_modules/node-gyp/test/test-find-accessible-sync.js b/server/node_modules/node-gyp/test/test-find-accessible-sync.js
new file mode 100644
index 0000000..0a2e584
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-find-accessible-sync.js
@@ -0,0 +1,84 @@
+'use strict'
+
+const test = require('tap').test
+const path = require('path')
+const requireInject = require('require-inject')
+const configure = requireInject('../lib/configure', {
+  'graceful-fs': {
+    closeSync: function () { return undefined },
+    openSync: function (path) {
+      if (readableFiles.some(function (f) { return f === path })) {
+        return 0
+      } else {
+        var error = new Error('ENOENT - not found')
+        throw error
+      }
+    }
+  }
+})
+
+const dir = path.sep + 'testdir'
+const readableFile = 'readable_file'
+const anotherReadableFile = 'another_readable_file'
+const readableFileInDir = 'somedir' + path.sep + readableFile
+const readableFiles = [
+  path.resolve(dir, readableFile),
+  path.resolve(dir, anotherReadableFile),
+  path.resolve(dir, readableFileInDir)
+]
+
+test('find accessible - empty array', function (t) {
+  t.plan(1)
+
+  var candidates = []
+  var found = configure.test.findAccessibleSync('test', dir, candidates)
+  t.strictEqual(found, undefined)
+})
+
+test('find accessible - single item array, readable', function (t) {
+  t.plan(1)
+
+  var candidates = [readableFile]
+  var found = configure.test.findAccessibleSync('test', dir, candidates)
+  t.strictEqual(found, path.resolve(dir, readableFile))
+})
+
+test('find accessible - single item array, readable in subdir', function (t) {
+  t.plan(1)
+
+  var candidates = [readableFileInDir]
+  var found = configure.test.findAccessibleSync('test', dir, candidates)
+  t.strictEqual(found, path.resolve(dir, readableFileInDir))
+})
+
+test('find accessible - single item array, unreadable', function (t) {
+  t.plan(1)
+
+  var candidates = ['unreadable_file']
+  var found = configure.test.findAccessibleSync('test', dir, candidates)
+  t.strictEqual(found, undefined)
+})
+
+test('find accessible - multi item array, no matches', function (t) {
+  t.plan(1)
+
+  var candidates = ['non_existent_file', 'unreadable_file']
+  var found = configure.test.findAccessibleSync('test', dir, candidates)
+  t.strictEqual(found, undefined)
+})
+
+test('find accessible - multi item array, single match', function (t) {
+  t.plan(1)
+
+  var candidates = ['non_existent_file', readableFile]
+  var found = configure.test.findAccessibleSync('test', dir, candidates)
+  t.strictEqual(found, path.resolve(dir, readableFile))
+})
+
+test('find accessible - multi item array, return first match', function (t) {
+  t.plan(1)
+
+  var candidates = ['non_existent_file', anotherReadableFile, readableFile]
+  var found = configure.test.findAccessibleSync('test', dir, candidates)
+  t.strictEqual(found, path.resolve(dir, anotherReadableFile))
+})
diff --git a/server/node_modules/node-gyp/test/test-find-node-directory.js b/server/node_modules/node-gyp/test/test-find-node-directory.js
new file mode 100644
index 0000000..f1380d1
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-find-node-directory.js
@@ -0,0 +1,119 @@
+'use strict'
+
+const test = require('tap').test
+const path = require('path')
+const findNodeDirectory = require('../lib/find-node-directory')
+
+const platforms = ['darwin', 'freebsd', 'linux', 'sunos', 'win32', 'aix']
+
+// we should find the directory based on the directory
+// the script is running in and it should match the layout
+// in a build tree where npm is installed in
+// .... /deps/npm
+test('test find-node-directory - node install', function (t) {
+  t.plan(platforms.length)
+  for (var next = 0; next < platforms.length; next++) {
+    var processObj = { execPath: '/x/y/bin/node', platform: platforms[next] }
+    t.equal(
+      findNodeDirectory('/x/deps/npm/node_modules/node-gyp/lib', processObj),
+      path.join('/x'))
+  }
+})
+
+// we should find the directory based on the directory
+// the script is running in and it should match the layout
+// in an installed tree where npm is installed in
+// .... /lib/node_modules/npm or .../node_modules/npm
+// depending on the patform
+test('test find-node-directory - node build', function (t) {
+  t.plan(platforms.length)
+  for (var next = 0; next < platforms.length; next++) {
+    var processObj = { execPath: '/x/y/bin/node', platform: platforms[next] }
+    if (platforms[next] === 'win32') {
+      t.equal(
+        findNodeDirectory('/y/node_modules/npm/node_modules/node-gyp/lib',
+          processObj), path.join('/y'))
+    } else {
+      t.equal(
+        findNodeDirectory('/y/lib/node_modules/npm/node_modules/node-gyp/lib',
+          processObj), path.join('/y'))
+    }
+  }
+})
+
+// we should find the directory based on the execPath
+// for node and match because it was in the bin directory
+test('test find-node-directory - node in bin directory', function (t) {
+  t.plan(platforms.length)
+  for (var next = 0; next < platforms.length; next++) {
+    var processObj = { execPath: '/x/y/bin/node', platform: platforms[next] }
+    t.equal(
+      findNodeDirectory('/nothere/npm/node_modules/node-gyp/lib', processObj),
+      path.join('/x/y'))
+  }
+})
+
+// we should find the directory based on the execPath
+// for node and match because it was in the Release directory
+test('test find-node-directory - node in build release dir', function (t) {
+  t.plan(platforms.length)
+  for (var next = 0; next < platforms.length; next++) {
+    var processObj
+    if (platforms[next] === 'win32') {
+      processObj = { execPath: '/x/y/Release/node', platform: platforms[next] }
+    } else {
+      processObj = {
+        execPath: '/x/y/out/Release/node',
+        platform: platforms[next]
+      }
+    }
+
+    t.equal(
+      findNodeDirectory('/nothere/npm/node_modules/node-gyp/lib', processObj),
+      path.join('/x/y'))
+  }
+})
+
+// we should find the directory based on the execPath
+// for node and match because it was in the Debug directory
+test('test find-node-directory - node in Debug release dir', function (t) {
+  t.plan(platforms.length)
+  for (var next = 0; next < platforms.length; next++) {
+    var processObj
+    if (platforms[next] === 'win32') {
+      processObj = { execPath: '/a/b/Debug/node', platform: platforms[next] }
+    } else {
+      processObj = { execPath: '/a/b/out/Debug/node', platform: platforms[next] }
+    }
+
+    t.equal(
+      findNodeDirectory('/nothere/npm/node_modules/node-gyp/lib', processObj),
+      path.join('/a/b'))
+  }
+})
+
+// we should not find it as it will not match based on the execPath nor
+// the directory from which the script is running
+test('test find-node-directory - not found', function (t) {
+  t.plan(platforms.length)
+  for (var next = 0; next < platforms.length; next++) {
+    var processObj = { execPath: '/x/y/z/y', platform: next }
+    t.equal(findNodeDirectory('/a/b/c/d', processObj), '')
+  }
+})
+
+// we should find the directory based on the directory
+// the script is running in and it should match the layout
+// in a build tree where npm is installed in
+// .... /deps/npm
+// same test as above but make sure additional directory entries
+// don't cause an issue
+test('test find-node-directory - node install', function (t) {
+  t.plan(platforms.length)
+  for (var next = 0; next < platforms.length; next++) {
+    var processObj = { execPath: '/x/y/bin/node', platform: platforms[next] }
+    t.equal(
+      findNodeDirectory('/x/y/z/a/b/c/deps/npm/node_modules/node-gyp/lib',
+        processObj), path.join('/x/y/z/a/b/c'))
+  }
+})
diff --git a/server/node_modules/node-gyp/test/test-find-python.js b/server/node_modules/node-gyp/test/test-find-python.js
new file mode 100644
index 0000000..67d0b26
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-find-python.js
@@ -0,0 +1,226 @@
+'use strict'
+
+delete process.env.PYTHON
+
+const test = require('tap').test
+const findPython = require('../lib/find-python')
+const execFile = require('child_process').execFile
+const PythonFinder = findPython.test.PythonFinder
+
+require('npmlog').level = 'warn'
+
+test('find python', function (t) {
+  t.plan(4)
+
+  findPython.test.findPython(null, function (err, found) {
+    t.strictEqual(err, null)
+    var proc = execFile(found, ['-V'], function (err, stdout, stderr) {
+      t.strictEqual(err, null)
+      t.ok(/Python 3/.test(stdout))
+      t.strictEqual(stderr, '')
+    })
+    proc.stdout.setEncoding('utf-8')
+    proc.stderr.setEncoding('utf-8')
+  })
+})
+
+function poison (object, property) {
+  function fail () {
+    console.error(Error(`Property ${property} should not have been accessed.`))
+    process.abort()
+  }
+  var descriptor = {
+    configurable: false,
+    enumerable: false,
+    get: fail,
+    set: fail
+  }
+  Object.defineProperty(object, property, descriptor)
+}
+
+function TestPythonFinder () {
+  PythonFinder.apply(this, arguments)
+}
+TestPythonFinder.prototype = Object.create(PythonFinder.prototype)
+// Silence npmlog - remove for debugging
+TestPythonFinder.prototype.log = {
+  silly: () => {},
+  verbose: () => {},
+  info: () => {},
+  warn: () => {},
+  error: () => {}
+}
+delete TestPythonFinder.prototype.env.NODE_GYP_FORCE_PYTHON
+
+test('find python - python', function (t) {
+  t.plan(6)
+
+  var f = new TestPythonFinder('python', done)
+  f.execFile = function (program, args, opts, cb) {
+    f.execFile = function (program, args, opts, cb) {
+      poison(f, 'execFile')
+      t.strictEqual(program, '/path/python')
+      t.ok(/sys\.version_info/.test(args[1]))
+      cb(null, '3.9.1')
+    }
+    t.strictEqual(program,
+      process.platform === 'win32' ? '"python"' : 'python')
+    t.ok(/sys\.executable/.test(args[1]))
+    cb(null, '/path/python')
+  }
+  f.findPython()
+
+  function done (err, python) {
+    t.strictEqual(err, null)
+    t.strictEqual(python, '/path/python')
+  }
+})
+
+test('find python - python too old', function (t) {
+  t.plan(2)
+
+  var f = new TestPythonFinder(null, done)
+  f.execFile = function (program, args, opts, cb) {
+    if (/sys\.executable/.test(args[args.length - 1])) {
+      cb(null, '/path/python')
+    } else if (/sys\.version_info/.test(args[args.length - 1])) {
+      cb(null, '2.3.4')
+    } else {
+      t.fail()
+    }
+  }
+  f.findPython()
+
+  function done (err) {
+    t.ok(/Could not find any Python/.test(err))
+    t.ok(/not supported/i.test(f.errorLog))
+  }
+})
+
+test('find python - no python', function (t) {
+  t.plan(2)
+
+  var f = new TestPythonFinder(null, done)
+  f.execFile = function (program, args, opts, cb) {
+    if (/sys\.executable/.test(args[args.length - 1])) {
+      cb(new Error('not found'))
+    } else if (/sys\.version_info/.test(args[args.length - 1])) {
+      cb(new Error('not a Python executable'))
+    } else {
+      t.fail()
+    }
+  }
+  f.findPython()
+
+  function done (err) {
+    t.ok(/Could not find any Python/.test(err))
+    t.ok(/not in PATH/.test(f.errorLog))
+  }
+})
+
+test('find python - no python2, no python, unix', function (t) {
+  t.plan(2)
+
+  var f = new TestPythonFinder(null, done)
+  f.checkPyLauncher = t.fail
+  f.win = false
+
+  f.execFile = function (program, args, opts, cb) {
+    if (/sys\.executable/.test(args[args.length - 1])) {
+      cb(new Error('not found'))
+    } else {
+      t.fail()
+    }
+  }
+  f.findPython()
+
+  function done (err) {
+    t.ok(/Could not find any Python/.test(err))
+    t.ok(/not in PATH/.test(f.errorLog))
+  }
+})
+
+test('find python - no python, use python launcher', function (t) {
+  t.plan(4)
+
+  var f = new TestPythonFinder(null, done)
+  f.win = true
+
+  f.execFile = function (program, args, opts, cb) {
+    if (program === 'py.exe') {
+      t.notEqual(args.indexOf('-3'), -1)
+      t.notEqual(args.indexOf('-c'), -1)
+      return cb(null, 'Z:\\snake.exe')
+    }
+    if (/sys\.executable/.test(args[args.length - 1])) {
+      cb(new Error('not found'))
+    } else if (f.winDefaultLocations.includes(program)) {
+      cb(new Error('not found'))
+    } else if (/sys\.version_info/.test(args[args.length - 1])) {
+      if (program === 'Z:\\snake.exe') {
+        cb(null, '3.9.0')
+      } else {
+        t.fail()
+      }
+    } else {
+      t.fail()
+    }
+  }
+  f.findPython()
+
+  function done (err, python) {
+    t.strictEqual(err, null)
+    t.strictEqual(python, 'Z:\\snake.exe')
+  }
+})
+
+test('find python - no python, no python launcher, good guess', function (t) {
+  t.plan(2)
+
+  var f = new TestPythonFinder(null, done)
+  f.win = true
+  const expectedProgram = f.winDefaultLocations[0]
+
+  f.execFile = function (program, args, opts, cb) {
+    if (program === 'py.exe') {
+      return cb(new Error('not found'))
+    }
+    if (/sys\.executable/.test(args[args.length - 1])) {
+      cb(new Error('not found'))
+    } else if (program === expectedProgram &&
+               /sys\.version_info/.test(args[args.length - 1])) {
+      cb(null, '3.7.3')
+    } else {
+      t.fail()
+    }
+  }
+  f.findPython()
+
+  function done (err, python) {
+    t.strictEqual(err, null)
+    t.ok(python === expectedProgram)
+  }
+})
+
+test('find python - no python, no python launcher, bad guess', function (t) {
+  t.plan(2)
+
+  var f = new TestPythonFinder(null, done)
+  f.win = true
+
+  f.execFile = function (program, args, opts, cb) {
+    if (/sys\.executable/.test(args[args.length - 1])) {
+      cb(new Error('not found'))
+    } else if (/sys\.version_info/.test(args[args.length - 1])) {
+      cb(new Error('not a Python executable'))
+    } else {
+      t.fail()
+    }
+  }
+  f.findPython()
+
+  function done (err) {
+    t.ok(/Could not find any Python/.test(err))
+    t.ok(/not in PATH/.test(f.errorLog))
+  }
+})
diff --git a/server/node_modules/node-gyp/test/test-find-visualstudio.js b/server/node_modules/node-gyp/test/test-find-visualstudio.js
new file mode 100644
index 0000000..1327cf8
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-find-visualstudio.js
@@ -0,0 +1,676 @@
+'use strict'
+
+const test = require('tap').test
+const fs = require('fs')
+const path = require('path')
+const findVisualStudio = require('../lib/find-visualstudio')
+const VisualStudioFinder = findVisualStudio.test.VisualStudioFinder
+
+const semverV1 = { major: 1, minor: 0, patch: 0 }
+
+delete process.env.VCINSTALLDIR
+
+function poison (object, property) {
+  function fail () {
+    console.error(Error(`Property ${property} should not have been accessed.`))
+    process.abort()
+  }
+  var descriptor = {
+    configurable: false,
+    enumerable: false,
+    get: fail,
+    set: fail
+  }
+  Object.defineProperty(object, property, descriptor)
+}
+
+function TestVisualStudioFinder () { VisualStudioFinder.apply(this, arguments) }
+TestVisualStudioFinder.prototype = Object.create(VisualStudioFinder.prototype)
+// Silence npmlog - remove for debugging
+TestVisualStudioFinder.prototype.log = {
+  silly: () => {},
+  verbose: () => {},
+  info: () => {},
+  warn: () => {},
+  error: () => {}
+}
+
+test('VS2013', function (t) {
+  t.plan(4)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info, {
+      msBuild: 'C:\\MSBuild12\\MSBuild.exe',
+      path: 'C:\\VS2013',
+      sdk: null,
+      toolset: 'v120',
+      version: '12.0',
+      versionMajor: 12,
+      versionMinor: 0,
+      versionYear: 2013
+    })
+  })
+
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    finder.parseData(new Error(), '', '', cb)
+  }
+  finder.regSearchKeys = (keys, value, addOpts, cb) => {
+    for (var i = 0; i < keys.length; ++i) {
+      const fullName = `${keys[i]}\\${value}`
+      switch (fullName) {
+        case 'HKLM\\Software\\Microsoft\\VisualStudio\\SxS\\VC7\\14.0':
+        case 'HKLM\\Software\\Wow6432Node\\Microsoft\\VisualStudio\\SxS\\VC7\\14.0':
+          continue
+        case 'HKLM\\Software\\Microsoft\\VisualStudio\\SxS\\VC7\\12.0':
+          t.pass(`expected search for registry value ${fullName}`)
+          return cb(null, 'C:\\VS2013\\VC\\')
+        case 'HKLM\\Software\\Microsoft\\MSBuild\\ToolsVersions\\12.0\\MSBuildToolsPath':
+          t.pass(`expected search for registry value ${fullName}`)
+          return cb(null, 'C:\\MSBuild12\\')
+        default:
+          t.fail(`unexpected search for registry value ${fullName}`)
+      }
+    }
+    return cb(new Error())
+  }
+  finder.findVisualStudio()
+})
+
+test('VS2013 should not be found on new node versions', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder({
+    major: 10,
+    minor: 0,
+    patch: 0
+  }, null, (err, info) => {
+    t.ok(/find .* Visual Studio/i.test(err), 'expect error')
+    t.false(info, 'no data')
+  })
+
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    const file = path.join(__dirname, 'fixtures', 'VS_2017_Unusable.txt')
+    const data = fs.readFileSync(file)
+    finder.parseData(null, data, '', cb)
+  }
+  finder.regSearchKeys = (keys, value, addOpts, cb) => {
+    for (var i = 0; i < keys.length; ++i) {
+      const fullName = `${keys[i]}\\${value}`
+      switch (fullName) {
+        case 'HKLM\\Software\\Microsoft\\VisualStudio\\SxS\\VC7\\14.0':
+        case 'HKLM\\Software\\Wow6432Node\\Microsoft\\VisualStudio\\SxS\\VC7\\14.0':
+          continue
+        default:
+          t.fail(`unexpected search for registry value ${fullName}`)
+      }
+    }
+    return cb(new Error())
+  }
+  finder.findVisualStudio()
+})
+
+test('VS2015', function (t) {
+  t.plan(4)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info, {
+      msBuild: 'C:\\MSBuild14\\MSBuild.exe',
+      path: 'C:\\VS2015',
+      sdk: null,
+      toolset: 'v140',
+      version: '14.0',
+      versionMajor: 14,
+      versionMinor: 0,
+      versionYear: 2015
+    })
+  })
+
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    finder.parseData(new Error(), '', '', cb)
+  }
+  finder.regSearchKeys = (keys, value, addOpts, cb) => {
+    for (var i = 0; i < keys.length; ++i) {
+      const fullName = `${keys[i]}\\${value}`
+      switch (fullName) {
+        case 'HKLM\\Software\\Microsoft\\VisualStudio\\SxS\\VC7\\14.0':
+          t.pass(`expected search for registry value ${fullName}`)
+          return cb(null, 'C:\\VS2015\\VC\\')
+        case 'HKLM\\Software\\Microsoft\\MSBuild\\ToolsVersions\\14.0\\MSBuildToolsPath':
+          t.pass(`expected search for registry value ${fullName}`)
+          return cb(null, 'C:\\MSBuild14\\')
+        default:
+          t.fail(`unexpected search for registry value ${fullName}`)
+      }
+    }
+    return cb(new Error())
+  }
+  finder.findVisualStudio()
+})
+
+test('error from PowerShell', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, null)
+
+  finder.parseData(new Error(), '', '', (info) => {
+    t.ok(/use PowerShell/i.test(finder.errorLog[0]), 'expect error')
+    t.false(info, 'no data')
+  })
+})
+
+test('empty output from PowerShell', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, null)
+
+  finder.parseData(null, '', '', (info) => {
+    t.ok(/use PowerShell/i.test(finder.errorLog[0]), 'expect error')
+    t.false(info, 'no data')
+  })
+})
+
+test('output from PowerShell not JSON', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, null)
+
+  finder.parseData(null, 'AAAABBBB', '', (info) => {
+    t.ok(/use PowerShell/i.test(finder.errorLog[0]), 'expect error')
+    t.false(info, 'no data')
+  })
+})
+
+test('wrong JSON from PowerShell', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, null)
+
+  finder.parseData(null, '{}', '', (info) => {
+    t.ok(/use PowerShell/i.test(finder.errorLog[0]), 'expect error')
+    t.false(info, 'no data')
+  })
+})
+
+test('empty JSON from PowerShell', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, null)
+
+  finder.parseData(null, '[]', '', (info) => {
+    t.ok(/find .* Visual Studio/i.test(finder.errorLog[0]), 'expect error')
+    t.false(info, 'no data')
+  })
+})
+
+test('future version', function (t) {
+  t.plan(3)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, null)
+
+  finder.parseData(null, JSON.stringify([{
+    packages: [
+      'Microsoft.VisualStudio.Component.VC.Tools.x86.x64',
+      'Microsoft.VisualStudio.Component.Windows10SDK.17763',
+      'Microsoft.VisualStudio.VC.MSBuild.Base'
+    ],
+    path: 'C:\\VS',
+    version: '9999.9999.9999.9999'
+  }]), '', (info) => {
+    t.ok(/unknown version/i.test(finder.errorLog[0]), 'expect error')
+    t.ok(/find .* Visual Studio/i.test(finder.errorLog[1]), 'expect error')
+    t.false(info, 'no data')
+  })
+})
+
+test('single unusable VS2017', function (t) {
+  t.plan(3)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, null)
+
+  const file = path.join(__dirname, 'fixtures', 'VS_2017_Unusable.txt')
+  const data = fs.readFileSync(file)
+  finder.parseData(null, data, '', (info) => {
+    t.ok(/checking/i.test(finder.errorLog[0]), 'expect error')
+    t.ok(/find .* Visual Studio/i.test(finder.errorLog[2]), 'expect error')
+    t.false(info, 'no data')
+  })
+})
+
+test('minimal VS2017 Build Tools', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info, {
+      msBuild: 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\' +
+        'BuildTools\\MSBuild\\15.0\\Bin\\MSBuild.exe',
+      path:
+        'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\BuildTools',
+      sdk: '10.0.17134.0',
+      toolset: 'v141',
+      version: '15.9.28307.665',
+      versionMajor: 15,
+      versionMinor: 9,
+      versionYear: 2017
+    })
+  })
+
+  poison(finder, 'regSearchKeys')
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    const file = path.join(__dirname, 'fixtures',
+      'VS_2017_BuildTools_minimal.txt')
+    const data = fs.readFileSync(file)
+    finder.parseData(null, data, '', cb)
+  }
+  finder.findVisualStudio()
+})
+
+test('VS2017 Community with C++ workload', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info, {
+      msBuild: 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\' +
+        'Community\\MSBuild\\15.0\\Bin\\MSBuild.exe',
+      path:
+        'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Community',
+      sdk: '10.0.17763.0',
+      toolset: 'v141',
+      version: '15.9.28307.665',
+      versionMajor: 15,
+      versionMinor: 9,
+      versionYear: 2017
+    })
+  })
+
+  poison(finder, 'regSearchKeys')
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    const file = path.join(__dirname, 'fixtures',
+      'VS_2017_Community_workload.txt')
+    const data = fs.readFileSync(file)
+    finder.parseData(null, data, '', cb)
+  }
+  finder.findVisualStudio()
+})
+
+test('VS2017 Express', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info, {
+      msBuild: 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\' +
+        'WDExpress\\MSBuild\\15.0\\Bin\\MSBuild.exe',
+      path:
+        'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\WDExpress',
+      sdk: '10.0.17763.0',
+      toolset: 'v141',
+      version: '15.9.28307.858',
+      versionMajor: 15,
+      versionMinor: 9,
+      versionYear: 2017
+    })
+  })
+
+  poison(finder, 'regSearchKeys')
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    const file = path.join(__dirname, 'fixtures', 'VS_2017_Express.txt')
+    const data = fs.readFileSync(file)
+    finder.parseData(null, data, '', cb)
+  }
+  finder.findVisualStudio()
+})
+
+test('VS2019 Preview with C++ workload', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info, {
+      msBuild: 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\' +
+        'Preview\\MSBuild\\Current\\Bin\\MSBuild.exe',
+      path:
+        'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Preview',
+      sdk: '10.0.17763.0',
+      toolset: 'v142',
+      version: '16.0.28608.199',
+      versionMajor: 16,
+      versionMinor: 0,
+      versionYear: 2019
+    })
+  })
+
+  poison(finder, 'regSearchKeys')
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    const file = path.join(__dirname, 'fixtures',
+      'VS_2019_Preview.txt')
+    const data = fs.readFileSync(file)
+    finder.parseData(null, data, '', cb)
+  }
+  finder.findVisualStudio()
+})
+
+test('minimal VS2019 Build Tools', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info, {
+      msBuild: 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\' +
+        'BuildTools\\MSBuild\\Current\\Bin\\MSBuild.exe',
+      path:
+        'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\BuildTools',
+      sdk: '10.0.17134.0',
+      toolset: 'v142',
+      version: '16.1.28922.388',
+      versionMajor: 16,
+      versionMinor: 1,
+      versionYear: 2019
+    })
+  })
+
+  poison(finder, 'regSearchKeys')
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    const file = path.join(__dirname, 'fixtures',
+      'VS_2019_BuildTools_minimal.txt')
+    const data = fs.readFileSync(file)
+    finder.parseData(null, data, '', cb)
+  }
+  finder.findVisualStudio()
+})
+
+test('VS2019 Community with C++ workload', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info, {
+      msBuild: 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\' +
+        'Community\\MSBuild\\Current\\Bin\\MSBuild.exe',
+      path:
+        'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Community',
+      sdk: '10.0.17763.0',
+      toolset: 'v142',
+      version: '16.1.28922.388',
+      versionMajor: 16,
+      versionMinor: 1,
+      versionYear: 2019
+    })
+  })
+
+  poison(finder, 'regSearchKeys')
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    const file = path.join(__dirname, 'fixtures',
+      'VS_2019_Community_workload.txt')
+    const data = fs.readFileSync(file)
+    finder.parseData(null, data, '', cb)
+  }
+  finder.findVisualStudio()
+})
+
+function allVsVersions (t, finder) {
+  finder.findVisualStudio2017OrNewer = (cb) => {
+    const data0 = JSON.parse(fs.readFileSync(path.join(__dirname, 'fixtures',
+      'VS_2017_Unusable.txt')))
+    const data1 = JSON.parse(fs.readFileSync(path.join(__dirname, 'fixtures',
+      'VS_2017_BuildTools_minimal.txt')))
+    const data2 = JSON.parse(fs.readFileSync(path.join(__dirname, 'fixtures',
+      'VS_2017_Community_workload.txt')))
+    const data3 = JSON.parse(fs.readFileSync(path.join(__dirname, 'fixtures',
+      'VS_2017_Express.txt')))
+    const data4 = JSON.parse(fs.readFileSync(path.join(__dirname, 'fixtures',
+      'VS_2019_Preview.txt')))
+    const data5 = JSON.parse(fs.readFileSync(path.join(__dirname, 'fixtures',
+      'VS_2019_BuildTools_minimal.txt')))
+    const data6 = JSON.parse(fs.readFileSync(path.join(__dirname, 'fixtures',
+      'VS_2019_Community_workload.txt')))
+    const data = JSON.stringify(data0.concat(data1, data2, data3, data4,
+      data5, data6))
+    finder.parseData(null, data, '', cb)
+  }
+  finder.regSearchKeys = (keys, value, addOpts, cb) => {
+    for (var i = 0; i < keys.length; ++i) {
+      const fullName = `${keys[i]}\\${value}`
+      switch (fullName) {
+        case 'HKLM\\Software\\Microsoft\\VisualStudio\\SxS\\VC7\\14.0':
+        case 'HKLM\\Software\\Microsoft\\VisualStudio\\SxS\\VC7\\12.0':
+          continue
+        case 'HKLM\\Software\\Wow6432Node\\Microsoft\\VisualStudio\\SxS\\VC7\\12.0':
+          return cb(null, 'C:\\VS2013\\VC\\')
+        case 'HKLM\\Software\\Microsoft\\MSBuild\\ToolsVersions\\12.0\\MSBuildToolsPath':
+          return cb(null, 'C:\\MSBuild12\\')
+        case 'HKLM\\Software\\Wow6432Node\\Microsoft\\VisualStudio\\SxS\\VC7\\14.0':
+          return cb(null, 'C:\\VS2015\\VC\\')
+        case 'HKLM\\Software\\Microsoft\\MSBuild\\ToolsVersions\\14.0\\MSBuildToolsPath':
+          return cb(null, 'C:\\MSBuild14\\')
+        default:
+          t.fail(`unexpected search for registry value ${fullName}`)
+      }
+    }
+    return cb(new Error())
+  }
+}
+
+test('fail when looking for invalid path', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, 'AABB', (err, info) => {
+    t.ok(/find .* Visual Studio/i.test(err), 'expect error')
+    t.false(info, 'no data')
+  })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('look for VS2013 by version number', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, '2013', (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info.versionYear, 2013)
+  })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('look for VS2013 by installation path', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, 'C:\\VS2013',
+    (err, info) => {
+      t.strictEqual(err, null)
+      t.deepEqual(info.path, 'C:\\VS2013')
+    })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('look for VS2015 by version number', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, '2015', (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info.versionYear, 2015)
+  })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('look for VS2015 by installation path', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, 'C:\\VS2015',
+    (err, info) => {
+      t.strictEqual(err, null)
+      t.deepEqual(info.path, 'C:\\VS2015')
+    })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('look for VS2017 by version number', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, '2017', (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info.versionYear, 2017)
+  })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('look for VS2017 by installation path', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1,
+    'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Community',
+    (err, info) => {
+      t.strictEqual(err, null)
+      t.deepEqual(info.path,
+        'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Community')
+    })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('look for VS2019 by version number', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, '2019', (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info.versionYear, 2019)
+  })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('look for VS2019 by installation path', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1,
+    'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\BuildTools',
+    (err, info) => {
+      t.strictEqual(err, null)
+      t.deepEqual(info.path,
+        'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\BuildTools')
+    })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('msvs_version match should be case insensitive', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1,
+    'c:\\program files (x86)\\microsoft visual studio\\2019\\BUILDTOOLS',
+    (err, info) => {
+      t.strictEqual(err, null)
+      t.deepEqual(info.path,
+        'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\BuildTools')
+    })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('latest version should be found by default', function (t) {
+  t.plan(2)
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info.versionYear, 2019)
+  })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('run on a usable VS Command Prompt', function (t) {
+  t.plan(2)
+
+  process.env.VCINSTALLDIR = 'C:\\VS2015\\VC'
+  // VSINSTALLDIR is not defined on Visual C++ Build Tools 2015
+  delete process.env.VSINSTALLDIR
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info.path, 'C:\\VS2015')
+  })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('VCINSTALLDIR match should be case insensitive', function (t) {
+  t.plan(2)
+
+  process.env.VCINSTALLDIR =
+    'c:\\program files (x86)\\microsoft visual studio\\2019\\BUILDTOOLS\\VC'
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.strictEqual(err, null)
+    t.deepEqual(info.path,
+      'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\BuildTools')
+  })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('run on a unusable VS Command Prompt', function (t) {
+  t.plan(2)
+
+  process.env.VCINSTALLDIR =
+    'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\BuildToolsUnusable\\VC'
+
+  const finder = new TestVisualStudioFinder(semverV1, null, (err, info) => {
+    t.ok(/find .* Visual Studio/i.test(err), 'expect error')
+    t.false(info, 'no data')
+  })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('run on a VS Command Prompt with matching msvs_version', function (t) {
+  t.plan(2)
+
+  process.env.VCINSTALLDIR = 'C:\\VS2015\\VC'
+
+  const finder = new TestVisualStudioFinder(semverV1, 'C:\\VS2015',
+    (err, info) => {
+      t.strictEqual(err, null)
+      t.deepEqual(info.path, 'C:\\VS2015')
+    })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
+
+test('run on a VS Command Prompt with mismatched msvs_version', function (t) {
+  t.plan(2)
+
+  process.env.VCINSTALLDIR =
+    'C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\BuildTools\\VC'
+
+  const finder = new TestVisualStudioFinder(semverV1, 'C:\\VS2015',
+    (err, info) => {
+      t.ok(/find .* Visual Studio/i.test(err), 'expect error')
+      t.false(info, 'no data')
+    })
+
+  allVsVersions(t, finder)
+  finder.findVisualStudio()
+})
diff --git a/server/node_modules/node-gyp/test/test-install.js b/server/node_modules/node-gyp/test/test-install.js
new file mode 100644
index 0000000..5039dc9
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-install.js
@@ -0,0 +1,46 @@
+'use strict'
+
+const { test } = require('tap')
+const { test: { install } } = require('../lib/install')
+const log = require('npmlog')
+
+log.level = 'error' // we expect a warning
+
+test('EACCES retry once', async (t) => {
+  t.plan(3)
+
+  const fs = {
+    promises: {
+      stat (_) {
+        const err = new Error()
+        err.code = 'EACCES'
+        t.ok(true)
+        throw err
+      }
+    }
+  }
+
+  const Gyp = {
+    devDir: __dirname,
+    opts: {
+      ensure: true
+    },
+    commands: {
+      install (argv, cb) {
+        install(fs, Gyp, argv).then(cb, cb)
+      },
+      remove (_, cb) {
+        cb()
+      }
+    }
+  }
+
+  try {
+    await install(fs, Gyp, [])
+  } catch (err) {
+    t.ok(true)
+    if (/"pre" versions of node cannot be installed/.test(err.message)) {
+      t.ok(true)
+    }
+  }
+})
diff --git a/server/node_modules/node-gyp/test/test-options.js b/server/node_modules/node-gyp/test/test-options.js
new file mode 100644
index 0000000..b2ac62c
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-options.js
@@ -0,0 +1,31 @@
+'use strict'
+
+const test = require('tap').test
+const gyp = require('../lib/node-gyp')
+
+test('options in environment', (t) => {
+  t.plan(1)
+
+  // `npm test` dumps a ton of npm_config_* variables in the environment.
+  Object.keys(process.env)
+    .filter((key) => /^npm_config_/.test(key))
+    .forEach((key) => { delete process.env[key] })
+
+  // in some platforms, certain keys are stubborn and cannot be removed
+  const keys = Object.keys(process.env)
+    .filter((key) => /^npm_config_/.test(key))
+    .map((key) => key.substring('npm_config_'.length))
+    .concat('argv', 'x')
+
+  // Zero-length keys should get filtered out.
+  process.env.npm_config_ = '42'
+  // Other keys should get added.
+  process.env.npm_config_x = '42'
+  // Except loglevel.
+  process.env.npm_config_loglevel = 'debug'
+
+  const g = gyp()
+  g.parseArgv(['rebuild']) // Also sets opts.argv.
+
+  t.deepEqual(Object.keys(g.opts).sort(), keys.sort())
+})
diff --git a/server/node_modules/node-gyp/test/test-process-release.js b/server/node_modules/node-gyp/test/test-process-release.js
new file mode 100644
index 0000000..c3ee070
--- /dev/null
+++ b/server/node_modules/node-gyp/test/test-process-release.js
@@ -0,0 +1,434 @@
+'use strict'
+
+const test = require('tap').test
+const processRelease = require('../lib/process-release')
+
+test('test process release - process.version = 0.8.20', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v0.8.20', null)
+
+  t.equal(release.semver.version, '0.8.20')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '0.8.20',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/dist/v0.8.20/',
+    tarballUrl: 'https://nodejs.org/dist/v0.8.20/node-v0.8.20.tar.gz',
+    shasumsUrl: 'https://nodejs.org/dist/v0.8.20/SHASUMS256.txt',
+    versionDir: '0.8.20',
+    ia32: { libUrl: 'https://nodejs.org/dist/v0.8.20/node.lib', libPath: 'node.lib' },
+    x64: { libUrl: 'https://nodejs.org/dist/v0.8.20/x64/node.lib', libPath: 'x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/dist/v0.8.20/arm64/node.lib', libPath: 'arm64/node.lib' }
+  })
+})
+
+test('test process release - process.version = 0.10.21', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v0.10.21', null)
+
+  t.equal(release.semver.version, '0.10.21')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '0.10.21',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/dist/v0.10.21/',
+    tarballUrl: 'https://nodejs.org/dist/v0.10.21/node-v0.10.21.tar.gz',
+    shasumsUrl: 'https://nodejs.org/dist/v0.10.21/SHASUMS256.txt',
+    versionDir: '0.10.21',
+    ia32: { libUrl: 'https://nodejs.org/dist/v0.10.21/node.lib', libPath: 'node.lib' },
+    x64: { libUrl: 'https://nodejs.org/dist/v0.10.21/x64/node.lib', libPath: 'x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/dist/v0.10.21/arm64/node.lib', libPath: 'arm64/node.lib' }
+  })
+})
+
+// prior to -headers.tar.gz
+test('test process release - process.version = 0.12.9', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v0.12.9', null)
+
+  t.equal(release.semver.version, '0.12.9')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '0.12.9',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/dist/v0.12.9/',
+    tarballUrl: 'https://nodejs.org/dist/v0.12.9/node-v0.12.9.tar.gz',
+    shasumsUrl: 'https://nodejs.org/dist/v0.12.9/SHASUMS256.txt',
+    versionDir: '0.12.9',
+    ia32: { libUrl: 'https://nodejs.org/dist/v0.12.9/node.lib', libPath: 'node.lib' },
+    x64: { libUrl: 'https://nodejs.org/dist/v0.12.9/x64/node.lib', libPath: 'x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/dist/v0.12.9/arm64/node.lib', libPath: 'arm64/node.lib' }
+  })
+})
+
+// prior to -headers.tar.gz
+test('test process release - process.version = 0.10.41', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v0.10.41', null)
+
+  t.equal(release.semver.version, '0.10.41')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '0.10.41',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/dist/v0.10.41/',
+    tarballUrl: 'https://nodejs.org/dist/v0.10.41/node-v0.10.41.tar.gz',
+    shasumsUrl: 'https://nodejs.org/dist/v0.10.41/SHASUMS256.txt',
+    versionDir: '0.10.41',
+    ia32: { libUrl: 'https://nodejs.org/dist/v0.10.41/node.lib', libPath: 'node.lib' },
+    x64: { libUrl: 'https://nodejs.org/dist/v0.10.41/x64/node.lib', libPath: 'x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/dist/v0.10.41/arm64/node.lib', libPath: 'arm64/node.lib' }
+  })
+})
+
+// has -headers.tar.gz
+test('test process release - process.release ~ node@0.10.42', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v0.10.42', null)
+
+  t.equal(release.semver.version, '0.10.42')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '0.10.42',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/dist/v0.10.42/',
+    tarballUrl: 'https://nodejs.org/dist/v0.10.42/node-v0.10.42-headers.tar.gz',
+    shasumsUrl: 'https://nodejs.org/dist/v0.10.42/SHASUMS256.txt',
+    versionDir: '0.10.42',
+    ia32: { libUrl: 'https://nodejs.org/dist/v0.10.42/node.lib', libPath: 'node.lib' },
+    x64: { libUrl: 'https://nodejs.org/dist/v0.10.42/x64/node.lib', libPath: 'x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/dist/v0.10.42/arm64/node.lib', libPath: 'arm64/node.lib' }
+  })
+})
+
+// has -headers.tar.gz
+test('test process release - process.release ~ node@0.12.10', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v0.12.10', null)
+
+  t.equal(release.semver.version, '0.12.10')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '0.12.10',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/dist/v0.12.10/',
+    tarballUrl: 'https://nodejs.org/dist/v0.12.10/node-v0.12.10-headers.tar.gz',
+    shasumsUrl: 'https://nodejs.org/dist/v0.12.10/SHASUMS256.txt',
+    versionDir: '0.12.10',
+    ia32: { libUrl: 'https://nodejs.org/dist/v0.12.10/node.lib', libPath: 'node.lib' },
+    x64: { libUrl: 'https://nodejs.org/dist/v0.12.10/x64/node.lib', libPath: 'x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/dist/v0.12.10/arm64/node.lib', libPath: 'arm64/node.lib' }
+  })
+})
+
+test('test process release - process.release ~ node@4.1.23', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v4.1.23', {
+    name: 'node',
+    headersUrl: 'https://nodejs.org/dist/v4.1.23/node-v4.1.23-headers.tar.gz'
+  })
+
+  t.equal(release.semver.version, '4.1.23')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '4.1.23',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/dist/v4.1.23/',
+    tarballUrl: 'https://nodejs.org/dist/v4.1.23/node-v4.1.23-headers.tar.gz',
+    shasumsUrl: 'https://nodejs.org/dist/v4.1.23/SHASUMS256.txt',
+    versionDir: '4.1.23',
+    ia32: { libUrl: 'https://nodejs.org/dist/v4.1.23/win-x86/node.lib', libPath: 'win-x86/node.lib' },
+    x64: { libUrl: 'https://nodejs.org/dist/v4.1.23/win-x64/node.lib', libPath: 'win-x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/dist/v4.1.23/win-arm64/node.lib', libPath: 'win-arm64/node.lib' }
+  })
+})
+
+test('test process release - process.release ~ node@4.1.23 / corp build', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v4.1.23', {
+    name: 'node',
+    headersUrl: 'https://some.custom.location/node-v4.1.23-headers.tar.gz'
+  })
+
+  t.equal(release.semver.version, '4.1.23')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '4.1.23',
+    name: 'node',
+    baseUrl: 'https://some.custom.location/',
+    tarballUrl: 'https://some.custom.location/node-v4.1.23-headers.tar.gz',
+    shasumsUrl: 'https://some.custom.location/SHASUMS256.txt',
+    versionDir: '4.1.23',
+    ia32: { libUrl: 'https://some.custom.location/win-x86/node.lib', libPath: 'win-x86/node.lib' },
+    x64: { libUrl: 'https://some.custom.location/win-x64/node.lib', libPath: 'win-x64/node.lib' },
+    arm64: { libUrl: 'https://some.custom.location/win-arm64/node.lib', libPath: 'win-arm64/node.lib' }
+  })
+})
+
+test('test process release - process.release ~ node@12.8.0 Windows', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v12.8.0', {
+    name: 'node',
+    sourceUrl: 'https://nodejs.org/download/release/v12.8.0/node-v12.8.0.tar.gz',
+    headersUrl: 'https://nodejs.org/download/release/v12.8.0/node-v12.8.0-headers.tar.gz',
+    libUrl: 'https://nodejs.org/download/release/v12.8.0/win-x64/node.lib'
+  })
+
+  t.equal(release.semver.version, '12.8.0')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '12.8.0',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/download/release/v12.8.0/',
+    tarballUrl: 'https://nodejs.org/download/release/v12.8.0/node-v12.8.0-headers.tar.gz',
+    shasumsUrl: 'https://nodejs.org/download/release/v12.8.0/SHASUMS256.txt',
+    versionDir: '12.8.0',
+    ia32: { libUrl: 'https://nodejs.org/download/release/v12.8.0/win-x86/node.lib', libPath: 'win-x86/node.lib' },
+    x64: { libUrl: 'https://nodejs.org/download/release/v12.8.0/win-x64/node.lib', libPath: 'win-x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/download/release/v12.8.0/win-arm64/node.lib', libPath: 'win-arm64/node.lib' }
+  })
+})
+
+test('test process release - process.release ~ node@12.8.0 Windows ARM64', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v12.8.0', {
+    name: 'node',
+    sourceUrl: 'https://unofficial-builds.nodejs.org/download/release/v12.8.0/node-v12.8.0.tar.gz',
+    headersUrl: 'https://unofficial-builds.nodejs.org/download/release/v12.8.0/node-v12.8.0-headers.tar.gz',
+    libUrl: 'https://unofficial-builds.nodejs.org/download/release/v12.8.0/win-arm64/node.lib'
+  })
+
+  t.equal(release.semver.version, '12.8.0')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '12.8.0',
+    name: 'node',
+    baseUrl: 'https://unofficial-builds.nodejs.org/download/release/v12.8.0/',
+    tarballUrl: 'https://unofficial-builds.nodejs.org/download/release/v12.8.0/node-v12.8.0-headers.tar.gz',
+    shasumsUrl: 'https://unofficial-builds.nodejs.org/download/release/v12.8.0/SHASUMS256.txt',
+    versionDir: '12.8.0',
+    ia32: { libUrl: 'https://unofficial-builds.nodejs.org/download/release/v12.8.0/win-x86/node.lib', libPath: 'win-x86/node.lib' },
+    x64: { libUrl: 'https://unofficial-builds.nodejs.org/download/release/v12.8.0/win-x64/node.lib', libPath: 'win-x64/node.lib' },
+    arm64: { libUrl: 'https://unofficial-builds.nodejs.org/download/release/v12.8.0/win-arm64/node.lib', libPath: 'win-arm64/node.lib' }
+  })
+})
+
+test('test process release - process.release ~ node@4.1.23 --target=0.10.40', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: { target: '0.10.40' } }, 'v4.1.23', {
+    name: 'node',
+    headersUrl: 'https://nodejs.org/dist/v4.1.23/node-v4.1.23-headers.tar.gz'
+  })
+
+  t.equal(release.semver.version, '0.10.40')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '0.10.40',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/dist/v0.10.40/',
+    tarballUrl: 'https://nodejs.org/dist/v0.10.40/node-v0.10.40.tar.gz',
+    shasumsUrl: 'https://nodejs.org/dist/v0.10.40/SHASUMS256.txt',
+    versionDir: '0.10.40',
+    ia32: { libUrl: 'https://nodejs.org/dist/v0.10.40/node.lib', libPath: 'node.lib' },
+    x64: { libUrl: 'https://nodejs.org/dist/v0.10.40/x64/node.lib', libPath: 'x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/dist/v0.10.40/arm64/node.lib', libPath: 'arm64/node.lib' }
+  })
+})
+
+test('test process release - process.release ~ node@4.1.23 --dist-url=https://foo.bar/baz', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: { 'dist-url': 'https://foo.bar/baz' } }, 'v4.1.23', {
+    name: 'node',
+    headersUrl: 'https://nodejs.org/dist/v4.1.23/node-v4.1.23-headers.tar.gz'
+  })
+
+  t.equal(release.semver.version, '4.1.23')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '4.1.23',
+    name: 'node',
+    baseUrl: 'https://foo.bar/baz/v4.1.23/',
+    tarballUrl: 'https://foo.bar/baz/v4.1.23/node-v4.1.23-headers.tar.gz',
+    shasumsUrl: 'https://foo.bar/baz/v4.1.23/SHASUMS256.txt',
+    versionDir: '4.1.23',
+    ia32: { libUrl: 'https://foo.bar/baz/v4.1.23/win-x86/node.lib', libPath: 'win-x86/node.lib' },
+    x64: { libUrl: 'https://foo.bar/baz/v4.1.23/win-x64/node.lib', libPath: 'win-x64/node.lib' },
+    arm64: { libUrl: 'https://foo.bar/baz/v4.1.23/win-arm64/node.lib', libPath: 'win-arm64/node.lib' }
+  })
+})
+
+test('test process release - process.release ~ frankenstein@4.1.23', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v4.1.23', {
+    name: 'frankenstein',
+    headersUrl: 'https://frankensteinjs.org/dist/v4.1.23/frankenstein-v4.1.23-headers.tar.gz'
+  })
+
+  t.equal(release.semver.version, '4.1.23')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '4.1.23',
+    name: 'frankenstein',
+    baseUrl: 'https://frankensteinjs.org/dist/v4.1.23/',
+    tarballUrl: 'https://frankensteinjs.org/dist/v4.1.23/frankenstein-v4.1.23-headers.tar.gz',
+    shasumsUrl: 'https://frankensteinjs.org/dist/v4.1.23/SHASUMS256.txt',
+    versionDir: 'frankenstein-4.1.23',
+    ia32: { libUrl: 'https://frankensteinjs.org/dist/v4.1.23/win-x86/frankenstein.lib', libPath: 'win-x86/frankenstein.lib' },
+    x64: { libUrl: 'https://frankensteinjs.org/dist/v4.1.23/win-x64/frankenstein.lib', libPath: 'win-x64/frankenstein.lib' },
+    arm64: { libUrl: 'https://frankensteinjs.org/dist/v4.1.23/win-arm64/frankenstein.lib', libPath: 'win-arm64/frankenstein.lib' }
+  })
+})
+
+test('test process release - process.release ~ frankenstein@4.1.23 --dist-url=http://foo.bar/baz/', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: { 'dist-url': 'http://foo.bar/baz/' } }, 'v4.1.23', {
+    name: 'frankenstein',
+    headersUrl: 'https://frankensteinjs.org/dist/v4.1.23/frankenstein-v4.1.23.tar.gz'
+  })
+
+  t.equal(release.semver.version, '4.1.23')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '4.1.23',
+    name: 'frankenstein',
+    baseUrl: 'http://foo.bar/baz/v4.1.23/',
+    tarballUrl: 'http://foo.bar/baz/v4.1.23/frankenstein-v4.1.23-headers.tar.gz',
+    shasumsUrl: 'http://foo.bar/baz/v4.1.23/SHASUMS256.txt',
+    versionDir: 'frankenstein-4.1.23',
+    ia32: { libUrl: 'http://foo.bar/baz/v4.1.23/win-x86/frankenstein.lib', libPath: 'win-x86/frankenstein.lib' },
+    x64: { libUrl: 'http://foo.bar/baz/v4.1.23/win-x64/frankenstein.lib', libPath: 'win-x64/frankenstein.lib' },
+    arm64: { libUrl: 'http://foo.bar/baz/v4.1.23/win-arm64/frankenstein.lib', libPath: 'win-arm64/frankenstein.lib' }
+  })
+})
+
+test('test process release - process.release ~ node@4.0.0-rc.4', function (t) {
+  t.plan(2)
+
+  var release = processRelease([], { opts: {} }, 'v4.0.0-rc.4', {
+    name: 'node',
+    headersUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/node-v4.0.0-rc.4-headers.tar.gz'
+  })
+
+  t.equal(release.semver.version, '4.0.0-rc.4')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '4.0.0-rc.4',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/',
+    tarballUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/node-v4.0.0-rc.4-headers.tar.gz',
+    shasumsUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/SHASUMS256.txt',
+    versionDir: '4.0.0-rc.4',
+    ia32: { libUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/win-x86/node.lib', libPath: 'win-x86/node.lib' },
+    x64: { libUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/win-x64/node.lib', libPath: 'win-x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/win-arm64/node.lib', libPath: 'win-arm64/node.lib' }
+  })
+})
+
+test('test process release - process.release ~ node@4.0.0-rc.4 passed as argv[0]', function (t) {
+  t.plan(2)
+
+  // note the missing 'v' on the arg, it should normalise when checking
+  // whether we're on the default or not
+  var release = processRelease(['4.0.0-rc.4'], { opts: {} }, 'v4.0.0-rc.4', {
+    name: 'node',
+    headersUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/node-v4.0.0-rc.4-headers.tar.gz'
+  })
+
+  t.equal(release.semver.version, '4.0.0-rc.4')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '4.0.0-rc.4',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/',
+    tarballUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/node-v4.0.0-rc.4-headers.tar.gz',
+    shasumsUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/SHASUMS256.txt',
+    versionDir: '4.0.0-rc.4',
+    ia32: { libUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/win-x86/node.lib', libPath: 'win-x86/node.lib' },
+    x64: { libUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/win-x64/node.lib', libPath: 'win-x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/win-arm64/node.lib', libPath: 'win-arm64/node.lib' }
+  })
+})
+
+test('test process release - process.release ~ node@4.0.0-rc.4 - bogus string passed as argv[0]', function (t) {
+  t.plan(2)
+
+  // additional arguments can be passed in on the commandline that should be ignored if they
+  // are not specifying a valid version @ position 0
+  var release = processRelease(['this is no version!'], { opts: {} }, 'v4.0.0-rc.4', {
+    name: 'node',
+    headersUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/node-v4.0.0-rc.4-headers.tar.gz'
+  })
+
+  t.equal(release.semver.version, '4.0.0-rc.4')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '4.0.0-rc.4',
+    name: 'node',
+    baseUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/',
+    tarballUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/node-v4.0.0-rc.4-headers.tar.gz',
+    shasumsUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/SHASUMS256.txt',
+    versionDir: '4.0.0-rc.4',
+    ia32: { libUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/win-x86/node.lib', libPath: 'win-x86/node.lib' },
+    x64: { libUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/win-x64/node.lib', libPath: 'win-x64/node.lib' },
+    arm64: { libUrl: 'https://nodejs.org/download/rc/v4.0.0-rc.4/win-arm64/node.lib', libPath: 'win-arm64/node.lib' }
+  })
+})
+
+test('test process release - NODEJS_ORG_MIRROR', function (t) {
+  t.plan(2)
+
+  process.env.NODEJS_ORG_MIRROR = 'http://foo.bar'
+
+  var release = processRelease([], { opts: {} }, 'v4.1.23', {
+    name: 'node',
+    headersUrl: 'https://nodejs.org/dist/v4.1.23/node-v4.1.23-headers.tar.gz'
+  })
+
+  t.equal(release.semver.version, '4.1.23')
+  delete release.semver
+
+  t.deepEqual(release, {
+    version: '4.1.23',
+    name: 'node',
+    baseUrl: 'http://foo.bar/v4.1.23/',
+    tarballUrl: 'http://foo.bar/v4.1.23/node-v4.1.23-headers.tar.gz',
+    shasumsUrl: 'http://foo.bar/v4.1.23/SHASUMS256.txt',
+    versionDir: '4.1.23',
+    ia32: { libUrl: 'http://foo.bar/v4.1.23/win-x86/node.lib', libPath: 'win-x86/node.lib' },
+    x64: { libUrl: 'http://foo.bar/v4.1.23/win-x64/node.lib', libPath: 'win-x64/node.lib' },
+    arm64: { libUrl: 'http://foo.bar/v4.1.23/win-arm64/node.lib', libPath: 'win-arm64/node.lib' }
+  })
+
+  delete process.env.NODEJS_ORG_MIRROR
+})
diff --git a/server/node_modules/node-gyp/update-gyp.py b/server/node_modules/node-gyp/update-gyp.py
new file mode 100755
index 0000000..bb84f07
--- /dev/null
+++ b/server/node_modules/node-gyp/update-gyp.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+
+import argparse
+import os
+import shutil
+import subprocess
+import tarfile
+import tempfile
+import urllib.request
+
+BASE_URL = "https://github.com/nodejs/gyp-next/archive/"
+CHECKOUT_PATH = os.path.dirname(os.path.realpath(__file__))
+CHECKOUT_GYP_PATH = os.path.join(CHECKOUT_PATH, "gyp")
+
+parser = argparse.ArgumentParser()
+parser.add_argument("tag", help="gyp tag to update to")
+args = parser.parse_args()
+
+tar_url = BASE_URL + args.tag + ".tar.gz"
+
+changed_files = subprocess.check_output(["git", "diff", "--name-only"]).strip()
+if changed_files:
+    raise Exception("Can't update gyp while you have uncommitted changes in node-gyp")
+
+with tempfile.TemporaryDirectory() as tmp_dir:
+    tar_file = os.path.join(tmp_dir, "gyp.tar.gz")
+    unzip_target = os.path.join(tmp_dir, "gyp")
+    with open(tar_file, "wb") as f:
+        print("Downloading gyp-next@" + args.tag + " into temporary directory...")
+        print("From: " + tar_url)
+        with urllib.request.urlopen(tar_url) as in_file:
+            f.write(in_file.read())
+
+        print("Unzipping...")
+        with tarfile.open(tar_file, "r:gz") as tar_ref:
+            tar_ref.extractall(unzip_target)
+
+        print("Moving to current checkout (" + CHECKOUT_PATH + ")...")
+        if os.path.exists(CHECKOUT_GYP_PATH):
+            shutil.rmtree(CHECKOUT_GYP_PATH)
+        shutil.move(
+            os.path.join(unzip_target, os.listdir(unzip_target)[0]), CHECKOUT_GYP_PATH
+        )
+
+subprocess.check_output(["git", "add", "gyp"], cwd=CHECKOUT_PATH)
+subprocess.check_output(["git", "commit", "-m", "feat(gyp): update gyp to " + args.tag])
diff --git a/server/node_modules/nopt/CHANGELOG.md b/server/node_modules/nopt/CHANGELOG.md
new file mode 100644
index 0000000..82a09fb
--- /dev/null
+++ b/server/node_modules/nopt/CHANGELOG.md
@@ -0,0 +1,58 @@
+### v4.0.1 (2016-12-14)
+
+#### WHOOPS
+
+* [`fb9b1ce`](https://github.com/npm/nopt/commit/fb9b1ce57b3c69b4f7819015be87719204f77ef6)
+  Merged so many patches at once that the code fencing
+  ([@adius](https://github.com/adius)) added got broken. Sorry,
+  ([@adius](https://github.com/adius))!
+  ([@othiym23](https://github.com/othiym23))
+
+### v4.0.0 (2016-12-13)
+
+#### BREAKING CHANGES
+
+* [`651d447`](https://github.com/npm/nopt/commit/651d4473946096d341a480bbe56793de3fc706aa)
+  When parsing String-typed arguments, if the next value is `""`, don't simply
+  swallow it. ([@samjonester](https://github.com/samjonester))
+
+#### PERFORMANCE TWEAKS
+
+* [`3370ce8`](https://github.com/npm/nopt/commit/3370ce87a7618ba228883861db84ddbcdff252a9)
+  Simplify initialization. ([@elidoran](https://github.com/elidoran))
+* [`356e58e`](https://github.com/npm/nopt/commit/356e58e3b3b431a4b1af7fd7bdee44c2c0526a09)
+  Store `Array.isArray(types[arg])` for reuse.
+  ([@elidoran](https://github.com/elidoran))
+* [`0d95e90`](https://github.com/npm/nopt/commit/0d95e90515844f266015b56d2c80b94e5d14a07e)
+  Interpret single-item type arrays as a single type.
+  ([@samjonester](https://github.com/samjonester))
+* [`07c69d3`](https://github.com/npm/nopt/commit/07c69d38b5186450941fbb505550becb78a0e925)
+  Simplify key-value extraction. ([@elidoran](https://github.com/elidoran))
+* [`39b6e5c`](https://github.com/npm/nopt/commit/39b6e5c65ac47f60cd43a1fbeece5cd4c834c254)
+  Only call `Date.parse(val)` once. ([@elidoran](https://github.com/elidoran))
+* [`934943d`](https://github.com/npm/nopt/commit/934943dffecb55123a2b15959fe2a359319a5dbd)
+  Use `osenv.home()` to find a user's home directory instead of assuming it's
+  always `$HOME`. ([@othiym23](https://github.com/othiym23))
+
+#### TEST & CI IMPROVEMENTS
+
+* [`326ffff`](https://github.com/npm/nopt/commit/326ffff7f78a00bcd316adecf69075f8a8093619)
+  Fix `/tmp` test to work on Windows.
+  ([@elidoran](https://github.com/elidoran))
+* [`c89d31a`](https://github.com/npm/nopt/commit/c89d31a49d14f2238bc6672db08da697bbc57f1b)
+  Only run Windows tests on Windows, only run Unix tests on a Unix.
+  ([@elidoran](https://github.com/elidoran))
+* [`affd3d1`](https://github.com/npm/nopt/commit/affd3d1d0addffa93006397b2013b18447339366)
+  Refresh Travis to run the tests against the currently-supported batch of npm
+  versions. ([@helio](https://github.com/helio)-frota)
+* [`55f9449`](https://github.com/npm/nopt/commit/55f94497d163ed4d16dd55fd6c4fb95cc440e66d)
+  `tap@8.0.1` ([@othiym23](https://github.com/othiym23))
+
+#### DOC TWEAKS
+
+* [`5271229`](https://github.com/npm/nopt/commit/5271229ee7c810217dd51616c086f5d9ab224581)
+  Use JavaScript code block for syntax highlighting.
+  ([@adius](https://github.com/adius))
+* [`c0d156f`](https://github.com/npm/nopt/commit/c0d156f229f9994c5dfcec4a8886eceff7a07682)
+  The code sample in the README had `many2: [ oneThing ]`, and now it has
+  `many2: [ two, things ]`. ([@silkentrance](https://github.com/silkentrance))
diff --git a/server/node_modules/nopt/LICENSE b/server/node_modules/nopt/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/nopt/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/nopt/README.md b/server/node_modules/nopt/README.md
new file mode 100644
index 0000000..a99531c
--- /dev/null
+++ b/server/node_modules/nopt/README.md
@@ -0,0 +1,213 @@
+If you want to write an option parser, and have it be good, there are
+two ways to do it.  The Right Way, and the Wrong Way.
+
+The Wrong Way is to sit down and write an option parser.  We've all done
+that.
+
+The Right Way is to write some complex configurable program with so many
+options that you hit the limit of your frustration just trying to
+manage them all, and defer it with duct-tape solutions until you see
+exactly to the core of the problem, and finally snap and write an
+awesome option parser.
+
+If you want to write an option parser, don't write an option parser.
+Write a package manager, or a source control system, or a service
+restarter, or an operating system.  You probably won't end up with a
+good one of those, but if you don't give up, and you are relentless and
+diligent enough in your procrastination, you may just end up with a very
+nice option parser.
+
+## USAGE
+
+```javascript
+// my-program.js
+var nopt = require("nopt")
+  , Stream = require("stream").Stream
+  , path = require("path")
+  , knownOpts = { "foo" : [String, null]
+                , "bar" : [Stream, Number]
+                , "baz" : path
+                , "bloo" : [ "big", "medium", "small" ]
+                , "flag" : Boolean
+                , "pick" : Boolean
+                , "many1" : [String, Array]
+                , "many2" : [path, Array]
+                }
+  , shortHands = { "foofoo" : ["--foo", "Mr. Foo"]
+                 , "b7" : ["--bar", "7"]
+                 , "m" : ["--bloo", "medium"]
+                 , "p" : ["--pick"]
+                 , "f" : ["--flag"]
+                 }
+             // everything is optional.
+             // knownOpts and shorthands default to {}
+             // arg list defaults to process.argv
+             // slice defaults to 2
+  , parsed = nopt(knownOpts, shortHands, process.argv, 2)
+console.log(parsed)
+```
+
+This would give you support for any of the following:
+
+```console
+$ node my-program.js --foo "blerp" --no-flag
+{ "foo" : "blerp", "flag" : false }
+
+$ node my-program.js ---bar 7 --foo "Mr. Hand" --flag
+{ bar: 7, foo: "Mr. Hand", flag: true }
+
+$ node my-program.js --foo "blerp" -f -----p
+{ foo: "blerp", flag: true, pick: true }
+
+$ node my-program.js -fp --foofoo
+{ foo: "Mr. Foo", flag: true, pick: true }
+
+$ node my-program.js --foofoo -- -fp  # -- stops the flag parsing.
+{ foo: "Mr. Foo", argv: { remain: ["-fp"] } }
+
+$ node my-program.js --blatzk -fp # unknown opts are ok.
+{ blatzk: true, flag: true, pick: true }
+
+$ node my-program.js --blatzk=1000 -fp # but you need to use = if they have a value
+{ blatzk: 1000, flag: true, pick: true }
+
+$ node my-program.js --no-blatzk -fp # unless they start with "no-"
+{ blatzk: false, flag: true, pick: true }
+
+$ node my-program.js --baz b/a/z # known paths are resolved.
+{ baz: "/Users/isaacs/b/a/z" }
+
+# if Array is one of the types, then it can take many
+# values, and will always be an array.  The other types provided
+# specify what types are allowed in the list.
+
+$ node my-program.js --many1 5 --many1 null --many1 foo
+{ many1: ["5", "null", "foo"] }
+
+$ node my-program.js --many2 foo --many2 bar
+{ many2: ["/path/to/foo", "path/to/bar"] }
+```
+
+Read the tests at the bottom of `lib/nopt.js` for more examples of
+what this puppy can do.
+
+## Types
+
+The following types are supported, and defined on `nopt.typeDefs`
+
+* String: A normal string.  No parsing is done.
+* path: A file system path.  Gets resolved against cwd if not absolute.
+* url: A url.  If it doesn't parse, it isn't accepted.
+* Number: Must be numeric.
+* Date: Must parse as a date. If it does, and `Date` is one of the options,
+  then it will return a Date object, not a string.
+* Boolean: Must be either `true` or `false`.  If an option is a boolean,
+  then it does not need a value, and its presence will imply `true` as
+  the value.  To negate boolean flags, do `--no-whatever` or `--whatever
+  false`
+* NaN: Means that the option is strictly not allowed.  Any value will
+  fail.
+* Stream: An object matching the "Stream" class in node.  Valuable
+  for use when validating programmatically.  (npm uses this to let you
+  supply any WriteStream on the `outfd` and `logfd` config options.)
+* Array: If `Array` is specified as one of the types, then the value
+  will be parsed as a list of options.  This means that multiple values
+  can be specified, and that the value will always be an array.
+
+If a type is an array of values not on this list, then those are
+considered valid values.  For instance, in the example above, the
+`--bloo` option can only be one of `"big"`, `"medium"`, or `"small"`,
+and any other value will be rejected.
+
+When parsing unknown fields, `"true"`, `"false"`, and `"null"` will be
+interpreted as their JavaScript equivalents.
+
+You can also mix types and values, or multiple types, in a list.  For
+instance `{ blah: [Number, null] }` would allow a value to be set to
+either a Number or null.  When types are ordered, this implies a
+preference, and the first type that can be used to properly interpret
+the value will be used.
+
+To define a new type, add it to `nopt.typeDefs`.  Each item in that
+hash is an object with a `type` member and a `validate` method.  The
+`type` member is an object that matches what goes in the type list.  The
+`validate` method is a function that gets called with `validate(data,
+key, val)`.  Validate methods should assign `data[key]` to the valid
+value of `val` if it can be handled properly, or return boolean
+`false` if it cannot.
+
+You can also call `nopt.clean(data, types, typeDefs)` to clean up a
+config object and remove its invalid properties.
+
+## Error Handling
+
+By default, nopt outputs a warning to standard error when invalid values for
+known options are found.  You can change this behavior by assigning a method
+to `nopt.invalidHandler`.  This method will be called with
+the offending `nopt.invalidHandler(key, val, types)`.
+
+If no `nopt.invalidHandler` is assigned, then it will console.error
+its whining.  If it is assigned to boolean `false` then the warning is
+suppressed.
+
+## Abbreviations
+
+Yes, they are supported.  If you define options like this:
+
+```javascript
+{ "foolhardyelephants" : Boolean
+, "pileofmonkeys" : Boolean }
+```
+
+Then this will work:
+
+```bash
+node program.js --foolhar --pil
+node program.js --no-f --pileofmon
+# etc.
+```
+
+## Shorthands
+
+Shorthands are a hash of shorter option names to a snippet of args that
+they expand to.
+
+If multiple one-character shorthands are all combined, and the
+combination does not unambiguously match any other option or shorthand,
+then they will be broken up into their constituent parts.  For example:
+
+```json
+{ "s" : ["--loglevel", "silent"]
+, "g" : "--global"
+, "f" : "--force"
+, "p" : "--parseable"
+, "l" : "--long"
+}
+```
+
+```bash
+npm ls -sgflp
+# just like doing this:
+npm ls --loglevel silent --global --force --long --parseable
+```
+
+## The Rest of the args
+
+The config object returned by nopt is given a special member called
+`argv`, which is an object with the following fields:
+
+* `remain`: The remaining args after all the parsing has occurred.
+* `original`: The args as they originally appeared.
+* `cooked`: The args after flags and shorthands are expanded.
+
+## Slicing
+
+Node programs are called with more or less the exact argv as it appears
+in C land, after the v8 and node-specific options have been plucked off.
+As such, `argv[0]` is always `node` and `argv[1]` is always the
+JavaScript program being run.
+
+That's usually not very useful to you.  So they're sliced off by
+default.  If you want them, then you can pass in `0` as the last
+argument, or any other number that you'd like to slice off the start of
+the list.
diff --git a/server/node_modules/nopt/bin/nopt.js b/server/node_modules/nopt/bin/nopt.js
new file mode 100755
index 0000000..3232d4c
--- /dev/null
+++ b/server/node_modules/nopt/bin/nopt.js
@@ -0,0 +1,54 @@
+#!/usr/bin/env node
+var nopt = require("../lib/nopt")
+  , path = require("path")
+  , types = { num: Number
+            , bool: Boolean
+            , help: Boolean
+            , list: Array
+            , "num-list": [Number, Array]
+            , "str-list": [String, Array]
+            , "bool-list": [Boolean, Array]
+            , str: String
+            , clear: Boolean
+            , config: Boolean
+            , length: Number
+            , file: path
+            }
+  , shorthands = { s: [ "--str", "astring" ]
+                 , b: [ "--bool" ]
+                 , nb: [ "--no-bool" ]
+                 , tft: [ "--bool-list", "--no-bool-list", "--bool-list", "true" ]
+                 , "?": ["--help"]
+                 , h: ["--help"]
+                 , H: ["--help"]
+                 , n: [ "--num", "125" ]
+                 , c: ["--config"]
+                 , l: ["--length"]
+                 , f: ["--file"]
+                 }
+  , parsed = nopt( types
+                 , shorthands
+                 , process.argv
+                 , 2 )
+
+console.log("parsed", parsed)
+
+if (parsed.help) {
+  console.log("")
+  console.log("nopt cli tester")
+  console.log("")
+  console.log("types")
+  console.log(Object.keys(types).map(function M (t) {
+    var type = types[t]
+    if (Array.isArray(type)) {
+      return [t, type.map(function (type) { return type.name })]
+    }
+    return [t, type && type.name]
+  }).reduce(function (s, i) {
+    s[i[0]] = i[1]
+    return s
+  }, {}))
+  console.log("")
+  console.log("shorthands")
+  console.log(shorthands)
+}
diff --git a/server/node_modules/nopt/lib/nopt.js b/server/node_modules/nopt/lib/nopt.js
new file mode 100644
index 0000000..ecfa5da
--- /dev/null
+++ b/server/node_modules/nopt/lib/nopt.js
@@ -0,0 +1,441 @@
+// info about each config option.
+
+var debug = process.env.DEBUG_NOPT || process.env.NOPT_DEBUG
+  ? function () { console.error.apply(console, arguments) }
+  : function () {}
+
+var url = require("url")
+  , path = require("path")
+  , Stream = require("stream").Stream
+  , abbrev = require("abbrev")
+  , os = require("os")
+
+module.exports = exports = nopt
+exports.clean = clean
+
+exports.typeDefs =
+  { String  : { type: String,  validate: validateString  }
+  , Boolean : { type: Boolean, validate: validateBoolean }
+  , url     : { type: url,     validate: validateUrl     }
+  , Number  : { type: Number,  validate: validateNumber  }
+  , path    : { type: path,    validate: validatePath    }
+  , Stream  : { type: Stream,  validate: validateStream  }
+  , Date    : { type: Date,    validate: validateDate    }
+  }
+
+function nopt (types, shorthands, args, slice) {
+  args = args || process.argv
+  types = types || {}
+  shorthands = shorthands || {}
+  if (typeof slice !== "number") slice = 2
+
+  debug(types, shorthands, args, slice)
+
+  args = args.slice(slice)
+  var data = {}
+    , key
+    , argv = {
+        remain: [],
+        cooked: args,
+        original: args.slice(0)
+      }
+
+  parse(args, data, argv.remain, types, shorthands)
+  // now data is full
+  clean(data, types, exports.typeDefs)
+  data.argv = argv
+  Object.defineProperty(data.argv, 'toString', { value: function () {
+    return this.original.map(JSON.stringify).join(" ")
+  }, enumerable: false })
+  return data
+}
+
+function clean (data, types, typeDefs) {
+  typeDefs = typeDefs || exports.typeDefs
+  var remove = {}
+    , typeDefault = [false, true, null, String, Array]
+
+  Object.keys(data).forEach(function (k) {
+    if (k === "argv") return
+    var val = data[k]
+      , isArray = Array.isArray(val)
+      , type = types[k]
+    if (!isArray) val = [val]
+    if (!type) type = typeDefault
+    if (type === Array) type = typeDefault.concat(Array)
+    if (!Array.isArray(type)) type = [type]
+
+    debug("val=%j", val)
+    debug("types=", type)
+    val = val.map(function (val) {
+      // if it's an unknown value, then parse false/true/null/numbers/dates
+      if (typeof val === "string") {
+        debug("string %j", val)
+        val = val.trim()
+        if ((val === "null" && ~type.indexOf(null))
+            || (val === "true" &&
+               (~type.indexOf(true) || ~type.indexOf(Boolean)))
+            || (val === "false" &&
+               (~type.indexOf(false) || ~type.indexOf(Boolean)))) {
+          val = JSON.parse(val)
+          debug("jsonable %j", val)
+        } else if (~type.indexOf(Number) && !isNaN(val)) {
+          debug("convert to number", val)
+          val = +val
+        } else if (~type.indexOf(Date) && !isNaN(Date.parse(val))) {
+          debug("convert to date", val)
+          val = new Date(val)
+        }
+      }
+
+      if (!types.hasOwnProperty(k)) {
+        return val
+      }
+
+      // allow `--no-blah` to set 'blah' to null if null is allowed
+      if (val === false && ~type.indexOf(null) &&
+          !(~type.indexOf(false) || ~type.indexOf(Boolean))) {
+        val = null
+      }
+
+      var d = {}
+      d[k] = val
+      debug("prevalidated val", d, val, types[k])
+      if (!validate(d, k, val, types[k], typeDefs)) {
+        if (exports.invalidHandler) {
+          exports.invalidHandler(k, val, types[k], data)
+        } else if (exports.invalidHandler !== false) {
+          debug("invalid: "+k+"="+val, types[k])
+        }
+        return remove
+      }
+      debug("validated val", d, val, types[k])
+      return d[k]
+    }).filter(function (val) { return val !== remove })
+
+    // if we allow Array specifically, then an empty array is how we
+    // express 'no value here', not null.  Allow it.
+    if (!val.length && type.indexOf(Array) === -1) {
+      debug('VAL HAS NO LENGTH, DELETE IT', val, k, type.indexOf(Array))
+      delete data[k]
+    }
+    else if (isArray) {
+      debug(isArray, data[k], val)
+      data[k] = val
+    } else data[k] = val[0]
+
+    debug("k=%s val=%j", k, val, data[k])
+  })
+}
+
+function validateString (data, k, val) {
+  data[k] = String(val)
+}
+
+function validatePath (data, k, val) {
+  if (val === true) return false
+  if (val === null) return true
+
+  val = String(val)
+
+  var isWin       = process.platform === 'win32'
+    , homePattern = isWin ? /^~(\/|\\)/ : /^~\//
+    , home        = os.homedir()
+
+  if (home && val.match(homePattern)) {
+    data[k] = path.resolve(home, val.substr(2))
+  } else {
+    data[k] = path.resolve(val)
+  }
+  return true
+}
+
+function validateNumber (data, k, val) {
+  debug("validate Number %j %j %j", k, val, isNaN(val))
+  if (isNaN(val)) return false
+  data[k] = +val
+}
+
+function validateDate (data, k, val) {
+  var s = Date.parse(val)
+  debug("validate Date %j %j %j", k, val, s)
+  if (isNaN(s)) return false
+  data[k] = new Date(val)
+}
+
+function validateBoolean (data, k, val) {
+  if (val instanceof Boolean) val = val.valueOf()
+  else if (typeof val === "string") {
+    if (!isNaN(val)) val = !!(+val)
+    else if (val === "null" || val === "false") val = false
+    else val = true
+  } else val = !!val
+  data[k] = val
+}
+
+function validateUrl (data, k, val) {
+  val = url.parse(String(val))
+  if (!val.host) return false
+  data[k] = val.href
+}
+
+function validateStream (data, k, val) {
+  if (!(val instanceof Stream)) return false
+  data[k] = val
+}
+
+function validate (data, k, val, type, typeDefs) {
+  // arrays are lists of types.
+  if (Array.isArray(type)) {
+    for (var i = 0, l = type.length; i < l; i ++) {
+      if (type[i] === Array) continue
+      if (validate(data, k, val, type[i], typeDefs)) return true
+    }
+    delete data[k]
+    return false
+  }
+
+  // an array of anything?
+  if (type === Array) return true
+
+  // NaN is poisonous.  Means that something is not allowed.
+  if (type !== type) {
+    debug("Poison NaN", k, val, type)
+    delete data[k]
+    return false
+  }
+
+  // explicit list of values
+  if (val === type) {
+    debug("Explicitly allowed %j", val)
+    // if (isArray) (data[k] = data[k] || []).push(val)
+    // else data[k] = val
+    data[k] = val
+    return true
+  }
+
+  // now go through the list of typeDefs, validate against each one.
+  var ok = false
+    , types = Object.keys(typeDefs)
+  for (var i = 0, l = types.length; i < l; i ++) {
+    debug("test type %j %j %j", k, val, types[i])
+    var t = typeDefs[types[i]]
+    if (t &&
+      ((type && type.name && t.type && t.type.name) ? (type.name === t.type.name) : (type === t.type))) {
+      var d = {}
+      ok = false !== t.validate(d, k, val)
+      val = d[k]
+      if (ok) {
+        // if (isArray) (data[k] = data[k] || []).push(val)
+        // else data[k] = val
+        data[k] = val
+        break
+      }
+    }
+  }
+  debug("OK? %j (%j %j %j)", ok, k, val, types[i])
+
+  if (!ok) delete data[k]
+  return ok
+}
+
+function parse (args, data, remain, types, shorthands) {
+  debug("parse", args, data, remain)
+
+  var key = null
+    , abbrevs = abbrev(Object.keys(types))
+    , shortAbbr = abbrev(Object.keys(shorthands))
+
+  for (var i = 0; i < args.length; i ++) {
+    var arg = args[i]
+    debug("arg", arg)
+
+    if (arg.match(/^-{2,}$/)) {
+      // done with keys.
+      // the rest are args.
+      remain.push.apply(remain, args.slice(i + 1))
+      args[i] = "--"
+      break
+    }
+    var hadEq = false
+    if (arg.charAt(0) === "-" && arg.length > 1) {
+      var at = arg.indexOf('=')
+      if (at > -1) {
+        hadEq = true
+        var v = arg.substr(at + 1)
+        arg = arg.substr(0, at)
+        args.splice(i, 1, arg, v)
+      }
+
+      // see if it's a shorthand
+      // if so, splice and back up to re-parse it.
+      var shRes = resolveShort(arg, shorthands, shortAbbr, abbrevs)
+      debug("arg=%j shRes=%j", arg, shRes)
+      if (shRes) {
+        debug(arg, shRes)
+        args.splice.apply(args, [i, 1].concat(shRes))
+        if (arg !== shRes[0]) {
+          i --
+          continue
+        }
+      }
+      arg = arg.replace(/^-+/, "")
+      var no = null
+      while (arg.toLowerCase().indexOf("no-") === 0) {
+        no = !no
+        arg = arg.substr(3)
+      }
+
+      if (abbrevs[arg]) arg = abbrevs[arg]
+
+      var argType = types[arg]
+      var isTypeArray = Array.isArray(argType)
+      if (isTypeArray && argType.length === 1) {
+        isTypeArray = false
+        argType = argType[0]
+      }
+
+      var isArray = argType === Array ||
+        isTypeArray && argType.indexOf(Array) !== -1
+
+      // allow unknown things to be arrays if specified multiple times.
+      if (!types.hasOwnProperty(arg) && data.hasOwnProperty(arg)) {
+        if (!Array.isArray(data[arg]))
+          data[arg] = [data[arg]]
+        isArray = true
+      }
+
+      var val
+        , la = args[i + 1]
+
+      var isBool = typeof no === 'boolean' ||
+        argType === Boolean ||
+        isTypeArray && argType.indexOf(Boolean) !== -1 ||
+        (typeof argType === 'undefined' && !hadEq) ||
+        (la === "false" &&
+         (argType === null ||
+          isTypeArray && ~argType.indexOf(null)))
+
+      if (isBool) {
+        // just set and move along
+        val = !no
+        // however, also support --bool true or --bool false
+        if (la === "true" || la === "false") {
+          val = JSON.parse(la)
+          la = null
+          if (no) val = !val
+          i ++
+        }
+
+        // also support "foo":[Boolean, "bar"] and "--foo bar"
+        if (isTypeArray && la) {
+          if (~argType.indexOf(la)) {
+            // an explicit type
+            val = la
+            i ++
+          } else if ( la === "null" && ~argType.indexOf(null) ) {
+            // null allowed
+            val = null
+            i ++
+          } else if ( !la.match(/^-{2,}[^-]/) &&
+                      !isNaN(la) &&
+                      ~argType.indexOf(Number) ) {
+            // number
+            val = +la
+            i ++
+          } else if ( !la.match(/^-[^-]/) && ~argType.indexOf(String) ) {
+            // string
+            val = la
+            i ++
+          }
+        }
+
+        if (isArray) (data[arg] = data[arg] || []).push(val)
+        else data[arg] = val
+
+        continue
+      }
+
+      if (argType === String) {
+        if (la === undefined) {
+          la = ""
+        } else if (la.match(/^-{1,2}[^-]+/)) {
+          la = ""
+          i --
+        }
+      }
+
+      if (la && la.match(/^-{2,}$/)) {
+        la = undefined
+        i --
+      }
+
+      val = la === undefined ? true : la
+      if (isArray) (data[arg] = data[arg] || []).push(val)
+      else data[arg] = val
+
+      i ++
+      continue
+    }
+    remain.push(arg)
+  }
+}
+
+function resolveShort (arg, shorthands, shortAbbr, abbrevs) {
+  // handle single-char shorthands glommed together, like
+  // npm ls -glp, but only if there is one dash, and only if
+  // all of the chars are single-char shorthands, and it's
+  // not a match to some other abbrev.
+  arg = arg.replace(/^-+/, '')
+
+  // if it's an exact known option, then don't go any further
+  if (abbrevs[arg] === arg)
+    return null
+
+  // if it's an exact known shortopt, same deal
+  if (shorthands[arg]) {
+    // make it an array, if it's a list of words
+    if (shorthands[arg] && !Array.isArray(shorthands[arg]))
+      shorthands[arg] = shorthands[arg].split(/\s+/)
+
+    return shorthands[arg]
+  }
+
+  // first check to see if this arg is a set of single-char shorthands
+  var singles = shorthands.___singles
+  if (!singles) {
+    singles = Object.keys(shorthands).filter(function (s) {
+      return s.length === 1
+    }).reduce(function (l,r) {
+      l[r] = true
+      return l
+    }, {})
+    shorthands.___singles = singles
+    debug('shorthand singles', singles)
+  }
+
+  var chrs = arg.split("").filter(function (c) {
+    return singles[c]
+  })
+
+  if (chrs.join("") === arg) return chrs.map(function (c) {
+    return shorthands[c]
+  }).reduce(function (l, r) {
+    return l.concat(r)
+  }, [])
+
+
+  // if it's an arg abbrev, and not a literal shorthand, then prefer the arg
+  if (abbrevs[arg] && !shorthands[arg])
+    return null
+
+  // if it's an abbr for a shorthand, then use that
+  if (shortAbbr[arg])
+    arg = shortAbbr[arg]
+
+  // make it an array, if it's a list of words
+  if (shorthands[arg] && !Array.isArray(shorthands[arg]))
+    shorthands[arg] = shorthands[arg].split(/\s+/)
+
+  return shorthands[arg]
+}
diff --git a/server/node_modules/nopt/package.json b/server/node_modules/nopt/package.json
new file mode 100644
index 0000000..12ed02d
--- /dev/null
+++ b/server/node_modules/nopt/package.json
@@ -0,0 +1,34 @@
+{
+  "name": "nopt",
+  "version": "5.0.0",
+  "description": "Option parsing for Node, supporting types, shorthands, etc. Used by npm.",
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "main": "lib/nopt.js",
+  "scripts": {
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags",
+    "test": "tap test/*.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/npm/nopt.git"
+  },
+  "bin": {
+    "nopt": "bin/nopt.js"
+  },
+  "license": "ISC",
+  "dependencies": {
+    "abbrev": "1"
+  },
+  "devDependencies": {
+    "tap": "^14.10.6"
+  },
+  "files": [
+    "bin",
+    "lib"
+  ],
+  "engines": {
+    "node": ">=6"
+  }
+}
diff --git a/server/node_modules/npmlog/LICENSE.md b/server/node_modules/npmlog/LICENSE.md
new file mode 100644
index 0000000..5fc208f
--- /dev/null
+++ b/server/node_modules/npmlog/LICENSE.md
@@ -0,0 +1,20 @@
+
+
+ISC License
+
+Copyright npm, Inc.
+
+Permission to use, copy, modify, and/or distribute this
+software for any purpose with or without fee is hereby
+granted, provided that the above copyright notice and this
+permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND NPM DISCLAIMS ALL
+WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
+EVENT SHALL NPM BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/npmlog/README.md b/server/node_modules/npmlog/README.md
new file mode 100644
index 0000000..268a4af
--- /dev/null
+++ b/server/node_modules/npmlog/README.md
@@ -0,0 +1,216 @@
+# npmlog
+
+The logger util that npm uses.
+
+This logger is very basic.  It does the logging for npm.  It supports
+custom levels and colored output.
+
+By default, logs are written to stderr.  If you want to send log messages
+to outputs other than streams, then you can change the `log.stream`
+member, or you can just listen to the events that it emits, and do
+whatever you want with them.
+
+# Installation
+
+```console
+npm install npmlog --save
+```
+
+# Basic Usage
+
+```javascript
+var log = require('npmlog')
+
+// additional stuff ---------------------------+
+// message ----------+                         |
+// prefix ----+      |                         |
+// level -+   |      |                         |
+//        v   v      v                         v
+    log.info('fyi', 'I have a kitty cat: %j', myKittyCat)
+```
+
+## log.level
+
+* {String}
+
+The level to display logs at.  Any logs at or above this level will be
+displayed.  The special level `silent` will prevent anything from being
+displayed ever.
+
+## log.record
+
+* {Array}
+
+An array of all the log messages that have been entered.
+
+## log.maxRecordSize
+
+* {Number}
+
+The maximum number of records to keep.  If log.record gets bigger than
+10% over this value, then it is sliced down to 90% of this value.
+
+The reason for the 10% window is so that it doesn't have to resize a
+large array on every log entry.
+
+## log.prefixStyle
+
+* {Object}
+
+A style object that specifies how prefixes are styled.  (See below)
+
+## log.headingStyle
+
+* {Object}
+
+A style object that specifies how the heading is styled.  (See below)
+
+## log.heading
+
+* {String} Default: ""
+
+If set, a heading that is printed at the start of every line.
+
+## log.stream
+
+* {Stream} Default: `process.stderr`
+
+The stream where output is written.
+
+## log.enableColor()
+
+Force colors to be used on all messages, regardless of the output
+stream.
+
+## log.disableColor()
+
+Disable colors on all messages.
+
+## log.enableProgress()
+
+Enable the display of log activity spinner and progress bar
+
+## log.disableProgress()
+
+Disable the display of a progress bar
+
+## log.enableUnicode()
+
+Force the unicode theme to be used for the progress bar.
+
+## log.disableUnicode()
+
+Disable the use of unicode in the progress bar.
+
+## log.setGaugeTemplate(template)
+
+Set a template for outputting the progress bar. See the [gauge documentation] for details.
+
+[gauge documentation]: https://npmjs.com/package/gauge
+
+## log.setGaugeThemeset(themes)
+
+Select a themeset to pick themes from for the progress bar. See the [gauge documentation] for details.
+
+## log.pause()
+
+Stop emitting messages to the stream, but do not drop them.
+
+## log.resume()
+
+Emit all buffered messages that were written while paused.
+
+## log.log(level, prefix, message, ...)
+
+* `level` {String} The level to emit the message at
+* `prefix` {String} A string prefix.  Set to "" to skip.
+* `message...` Arguments to `util.format`
+
+Emit a log message at the specified level.
+
+## log\[level](prefix, message, ...)
+
+For example,
+
+* log.silly(prefix, message, ...)
+* log.verbose(prefix, message, ...)
+* log.info(prefix, message, ...)
+* log.http(prefix, message, ...)
+* log.warn(prefix, message, ...)
+* log.error(prefix, message, ...)
+
+Like `log.log(level, prefix, message, ...)`.  In this way, each level is
+given a shorthand, so you can do `log.info(prefix, message)`.
+
+## log.addLevel(level, n, style, disp)
+
+* `level` {String} Level indicator
+* `n` {Number} The numeric level
+* `style` {Object} Object with fg, bg, inverse, etc.
+* `disp` {String} Optional replacement for `level` in the output.
+
+Sets up a new level with a shorthand function and so forth.
+
+Note that if the number is `Infinity`, then setting the level to that
+will cause all log messages to be suppressed.  If the number is
+`-Infinity`, then the only way to show it is to enable all log messages.
+
+## log.newItem(name, todo, weight)
+
+* `name` {String} Optional; progress item name.
+* `todo` {Number} Optional; total amount of work to be done. Default 0.
+* `weight` {Number} Optional; the weight of this item relative to others. Default 1.
+
+This adds a new `are-we-there-yet` item tracker to the progress tracker. The
+object returned has the `log[level]` methods but is otherwise an
+`are-we-there-yet` `Tracker` object.
+
+## log.newStream(name, todo, weight)
+
+This adds a new `are-we-there-yet` stream tracker to the progress tracker. The
+object returned has the `log[level]` methods but is otherwise an
+`are-we-there-yet` `TrackerStream` object.
+
+## log.newGroup(name, weight)
+
+This adds a new `are-we-there-yet` tracker group to the progress tracker. The
+object returned has the `log[level]` methods but is otherwise an
+`are-we-there-yet` `TrackerGroup` object.
+
+# Events
+
+Events are all emitted with the message object.
+
+* `log` Emitted for all messages
+* `log.<level>` Emitted for all messages with the `<level>` level.
+* `<prefix>` Messages with prefixes also emit their prefix as an event.
+
+# Style Objects
+
+Style objects can have the following fields:
+
+* `fg` {String} Color for the foreground text
+* `bg` {String} Color for the background
+* `bold`, `inverse`, `underline` {Boolean} Set the associated property
+* `bell` {Boolean} Make a noise (This is pretty annoying, probably.)
+
+# Message Objects
+
+Every log event is emitted with a message object, and the `log.record`
+list contains all of them that have been created.  They have the
+following fields:
+
+* `id` {Number}
+* `level` {String}
+* `prefix` {String}
+* `message` {String} Result of `util.format()`
+* `messageRaw` {Array} Arguments to `util.format()`
+
+# Blocking TTYs
+
+We use [`set-blocking`](https://npmjs.com/package/set-blocking) to set
+stderr and stdout blocking if they are tty's and have the setBlocking call.
+This is a work around for an issue in early versions of Node.js 6.x, which
+made stderr and stdout non-blocking on OSX. (They are always blocking
+Windows and were never blocking on Linux.) `npmlog` needs them to be blocking
+so that it can allow output to stdout and stderr to be interlaced.
diff --git a/server/node_modules/npmlog/lib/log.js b/server/node_modules/npmlog/lib/log.js
new file mode 100644
index 0000000..be650c6
--- /dev/null
+++ b/server/node_modules/npmlog/lib/log.js
@@ -0,0 +1,404 @@
+'use strict'
+var Progress = require('are-we-there-yet')
+var Gauge = require('gauge')
+var EE = require('events').EventEmitter
+var log = exports = module.exports = new EE()
+var util = require('util')
+
+var setBlocking = require('set-blocking')
+var consoleControl = require('console-control-strings')
+
+setBlocking(true)
+var stream = process.stderr
+Object.defineProperty(log, 'stream', {
+  set: function (newStream) {
+    stream = newStream
+    if (this.gauge) {
+      this.gauge.setWriteTo(stream, stream)
+    }
+  },
+  get: function () {
+    return stream
+  },
+})
+
+// by default, decide based on tty-ness.
+var colorEnabled
+log.useColor = function () {
+  return colorEnabled != null ? colorEnabled : stream.isTTY
+}
+
+log.enableColor = function () {
+  colorEnabled = true
+  this.gauge.setTheme({ hasColor: colorEnabled, hasUnicode: unicodeEnabled })
+}
+log.disableColor = function () {
+  colorEnabled = false
+  this.gauge.setTheme({ hasColor: colorEnabled, hasUnicode: unicodeEnabled })
+}
+
+// default level
+log.level = 'info'
+
+log.gauge = new Gauge(stream, {
+  enabled: false, // no progress bars unless asked
+  theme: { hasColor: log.useColor() },
+  template: [
+    { type: 'progressbar', length: 20 },
+    { type: 'activityIndicator', kerning: 1, length: 1 },
+    { type: 'section', default: '' },
+    ':',
+    { type: 'logline', kerning: 1, default: '' },
+  ],
+})
+
+log.tracker = new Progress.TrackerGroup()
+
+// we track this separately as we may need to temporarily disable the
+// display of the status bar for our own loggy purposes.
+log.progressEnabled = log.gauge.isEnabled()
+
+var unicodeEnabled
+
+log.enableUnicode = function () {
+  unicodeEnabled = true
+  this.gauge.setTheme({ hasColor: this.useColor(), hasUnicode: unicodeEnabled })
+}
+
+log.disableUnicode = function () {
+  unicodeEnabled = false
+  this.gauge.setTheme({ hasColor: this.useColor(), hasUnicode: unicodeEnabled })
+}
+
+log.setGaugeThemeset = function (themes) {
+  this.gauge.setThemeset(themes)
+}
+
+log.setGaugeTemplate = function (template) {
+  this.gauge.setTemplate(template)
+}
+
+log.enableProgress = function () {
+  if (this.progressEnabled) {
+    return
+  }
+
+  this.progressEnabled = true
+  this.tracker.on('change', this.showProgress)
+  if (this._paused) {
+    return
+  }
+
+  this.gauge.enable()
+}
+
+log.disableProgress = function () {
+  if (!this.progressEnabled) {
+    return
+  }
+  this.progressEnabled = false
+  this.tracker.removeListener('change', this.showProgress)
+  this.gauge.disable()
+}
+
+var trackerConstructors = ['newGroup', 'newItem', 'newStream']
+
+var mixinLog = function (tracker) {
+  // mixin the public methods from log into the tracker
+  // (except: conflicts and one's we handle specially)
+  Object.keys(log).forEach(function (P) {
+    if (P[0] === '_') {
+      return
+    }
+
+    if (trackerConstructors.filter(function (C) {
+      return C === P
+    }).length) {
+      return
+    }
+
+    if (tracker[P]) {
+      return
+    }
+
+    if (typeof log[P] !== 'function') {
+      return
+    }
+
+    var func = log[P]
+    tracker[P] = function () {
+      return func.apply(log, arguments)
+    }
+  })
+  // if the new tracker is a group, make sure any subtrackers get
+  // mixed in too
+  if (tracker instanceof Progress.TrackerGroup) {
+    trackerConstructors.forEach(function (C) {
+      var func = tracker[C]
+      tracker[C] = function () {
+        return mixinLog(func.apply(tracker, arguments))
+      }
+    })
+  }
+  return tracker
+}
+
+// Add tracker constructors to the top level log object
+trackerConstructors.forEach(function (C) {
+  log[C] = function () {
+    return mixinLog(this.tracker[C].apply(this.tracker, arguments))
+  }
+})
+
+log.clearProgress = function (cb) {
+  if (!this.progressEnabled) {
+    return cb && process.nextTick(cb)
+  }
+
+  this.gauge.hide(cb)
+}
+
+log.showProgress = function (name, completed) {
+  if (!this.progressEnabled) {
+    return
+  }
+
+  var values = {}
+  if (name) {
+    values.section = name
+  }
+
+  var last = log.record[log.record.length - 1]
+  if (last) {
+    values.subsection = last.prefix
+    var disp = log.disp[last.level] || last.level
+    var logline = this._format(disp, log.style[last.level])
+    if (last.prefix) {
+      logline += ' ' + this._format(last.prefix, this.prefixStyle)
+    }
+
+    logline += ' ' + last.message.split(/\r?\n/)[0]
+    values.logline = logline
+  }
+  values.completed = completed || this.tracker.completed()
+  this.gauge.show(values)
+}.bind(log) // bind for use in tracker's on-change listener
+
+// temporarily stop emitting, but don't drop
+log.pause = function () {
+  this._paused = true
+  if (this.progressEnabled) {
+    this.gauge.disable()
+  }
+}
+
+log.resume = function () {
+  if (!this._paused) {
+    return
+  }
+
+  this._paused = false
+
+  var b = this._buffer
+  this._buffer = []
+  b.forEach(function (m) {
+    this.emitLog(m)
+  }, this)
+  if (this.progressEnabled) {
+    this.gauge.enable()
+  }
+}
+
+log._buffer = []
+
+var id = 0
+log.record = []
+log.maxRecordSize = 10000
+log.log = function (lvl, prefix, message) {
+  var l = this.levels[lvl]
+  if (l === undefined) {
+    return this.emit('error', new Error(util.format(
+      'Undefined log level: %j', lvl)))
+  }
+
+  var a = new Array(arguments.length - 2)
+  var stack = null
+  for (var i = 2; i < arguments.length; i++) {
+    var arg = a[i - 2] = arguments[i]
+
+    // resolve stack traces to a plain string.
+    if (typeof arg === 'object' && arg instanceof Error && arg.stack) {
+      Object.defineProperty(arg, 'stack', {
+        value: stack = arg.stack + '',
+        enumerable: true,
+        writable: true,
+      })
+    }
+  }
+  if (stack) {
+    a.unshift(stack + '\n')
+  }
+  message = util.format.apply(util, a)
+
+  var m = {
+    id: id++,
+    level: lvl,
+    prefix: String(prefix || ''),
+    message: message,
+    messageRaw: a,
+  }
+
+  this.emit('log', m)
+  this.emit('log.' + lvl, m)
+  if (m.prefix) {
+    this.emit(m.prefix, m)
+  }
+
+  this.record.push(m)
+  var mrs = this.maxRecordSize
+  var n = this.record.length - mrs
+  if (n > mrs / 10) {
+    var newSize = Math.floor(mrs * 0.9)
+    this.record = this.record.slice(-1 * newSize)
+  }
+
+  this.emitLog(m)
+}.bind(log)
+
+log.emitLog = function (m) {
+  if (this._paused) {
+    this._buffer.push(m)
+    return
+  }
+  if (this.progressEnabled) {
+    this.gauge.pulse(m.prefix)
+  }
+
+  var l = this.levels[m.level]
+  if (l === undefined) {
+    return
+  }
+
+  if (l < this.levels[this.level]) {
+    return
+  }
+
+  if (l > 0 && !isFinite(l)) {
+    return
+  }
+
+  // If 'disp' is null or undefined, use the lvl as a default
+  // Allows: '', 0 as valid disp
+  var disp = log.disp[m.level] != null ? log.disp[m.level] : m.level
+  this.clearProgress()
+  m.message.split(/\r?\n/).forEach(function (line) {
+    var heading = this.heading
+    if (heading) {
+      this.write(heading, this.headingStyle)
+      this.write(' ')
+    }
+    this.write(disp, log.style[m.level])
+    var p = m.prefix || ''
+    if (p) {
+      this.write(' ')
+    }
+
+    this.write(p, this.prefixStyle)
+    this.write(' ' + line + '\n')
+  }, this)
+  this.showProgress()
+}
+
+log._format = function (msg, style) {
+  if (!stream) {
+    return
+  }
+
+  var output = ''
+  if (this.useColor()) {
+    style = style || {}
+    var settings = []
+    if (style.fg) {
+      settings.push(style.fg)
+    }
+
+    if (style.bg) {
+      settings.push('bg' + style.bg[0].toUpperCase() + style.bg.slice(1))
+    }
+
+    if (style.bold) {
+      settings.push('bold')
+    }
+
+    if (style.underline) {
+      settings.push('underline')
+    }
+
+    if (style.inverse) {
+      settings.push('inverse')
+    }
+
+    if (settings.length) {
+      output += consoleControl.color(settings)
+    }
+
+    if (style.beep) {
+      output += consoleControl.beep()
+    }
+  }
+  output += msg
+  if (this.useColor()) {
+    output += consoleControl.color('reset')
+  }
+
+  return output
+}
+
+log.write = function (msg, style) {
+  if (!stream) {
+    return
+  }
+
+  stream.write(this._format(msg, style))
+}
+
+log.addLevel = function (lvl, n, style, disp) {
+  // If 'disp' is null or undefined, use the lvl as a default
+  if (disp == null) {
+    disp = lvl
+  }
+
+  this.levels[lvl] = n
+  this.style[lvl] = style
+  if (!this[lvl]) {
+    this[lvl] = function () {
+      var a = new Array(arguments.length + 1)
+      a[0] = lvl
+      for (var i = 0; i < arguments.length; i++) {
+        a[i + 1] = arguments[i]
+      }
+
+      return this.log.apply(this, a)
+    }.bind(this)
+  }
+  this.disp[lvl] = disp
+}
+
+log.prefixStyle = { fg: 'magenta' }
+log.headingStyle = { fg: 'white', bg: 'black' }
+
+log.style = {}
+log.levels = {}
+log.disp = {}
+log.addLevel('silly', -Infinity, { inverse: true }, 'sill')
+log.addLevel('verbose', 1000, { fg: 'cyan', bg: 'black' }, 'verb')
+log.addLevel('info', 2000, { fg: 'green' })
+log.addLevel('timing', 2500, { fg: 'green', bg: 'black' })
+log.addLevel('http', 3000, { fg: 'green', bg: 'black' })
+log.addLevel('notice', 3500, { fg: 'cyan', bg: 'black' })
+log.addLevel('warn', 4000, { fg: 'black', bg: 'yellow' }, 'WARN')
+log.addLevel('error', 5000, { fg: 'red', bg: 'black' }, 'ERR!')
+log.addLevel('silent', Infinity)
+
+// allow 'error' prefix
+log.on('error', function () {})
diff --git a/server/node_modules/npmlog/package.json b/server/node_modules/npmlog/package.json
new file mode 100644
index 0000000..bdb5a38
--- /dev/null
+++ b/server/node_modules/npmlog/package.json
@@ -0,0 +1,51 @@
+{
+  "author": "GitHub Inc.",
+  "name": "npmlog",
+  "description": "logger for npm",
+  "version": "6.0.2",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/npm/npmlog.git"
+  },
+  "main": "lib/log.js",
+  "files": [
+    "bin/",
+    "lib/"
+  ],
+  "scripts": {
+    "test": "tap",
+    "npmclilint": "npmcli-lint",
+    "lint": "eslint \"**/*.js\"",
+    "lintfix": "npm run lint -- --fix",
+    "posttest": "npm run lint",
+    "postsnap": "npm run lintfix --",
+    "postlint": "template-oss-check",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags",
+    "snap": "tap",
+    "template-oss-apply": "template-oss-apply --force"
+  },
+  "dependencies": {
+    "are-we-there-yet": "^3.0.0",
+    "console-control-strings": "^1.1.0",
+    "gauge": "^4.0.3",
+    "set-blocking": "^2.0.0"
+  },
+  "devDependencies": {
+    "@npmcli/eslint-config": "^3.0.1",
+    "@npmcli/template-oss": "3.4.1",
+    "tap": "^16.0.1"
+  },
+  "license": "ISC",
+  "engines": {
+    "node": "^12.13.0 || ^14.15.0 || >=16.0.0"
+  },
+  "tap": {
+    "branches": 95
+  },
+  "templateOSS": {
+    "//@npmcli/template-oss": "This file is partially managed by @npmcli/template-oss. Edits may be overwritten.",
+    "version": "3.4.1"
+  }
+}
diff --git a/server/node_modules/object-assign/index.js b/server/node_modules/object-assign/index.js
new file mode 100644
index 0000000..0930cf8
--- /dev/null
+++ b/server/node_modules/object-assign/index.js
@@ -0,0 +1,90 @@
+/*
+object-assign
+(c) Sindre Sorhus
+@license MIT
+*/
+
+'use strict';
+/* eslint-disable no-unused-vars */
+var getOwnPropertySymbols = Object.getOwnPropertySymbols;
+var hasOwnProperty = Object.prototype.hasOwnProperty;
+var propIsEnumerable = Object.prototype.propertyIsEnumerable;
+
+function toObject(val) {
+	if (val === null || val === undefined) {
+		throw new TypeError('Object.assign cannot be called with null or undefined');
+	}
+
+	return Object(val);
+}
+
+function shouldUseNative() {
+	try {
+		if (!Object.assign) {
+			return false;
+		}
+
+		// Detect buggy property enumeration order in older V8 versions.
+
+		// https://bugs.chromium.org/p/v8/issues/detail?id=4118
+		var test1 = new String('abc');  // eslint-disable-line no-new-wrappers
+		test1[5] = 'de';
+		if (Object.getOwnPropertyNames(test1)[0] === '5') {
+			return false;
+		}
+
+		// https://bugs.chromium.org/p/v8/issues/detail?id=3056
+		var test2 = {};
+		for (var i = 0; i < 10; i++) {
+			test2['_' + String.fromCharCode(i)] = i;
+		}
+		var order2 = Object.getOwnPropertyNames(test2).map(function (n) {
+			return test2[n];
+		});
+		if (order2.join('') !== '0123456789') {
+			return false;
+		}
+
+		// https://bugs.chromium.org/p/v8/issues/detail?id=3056
+		var test3 = {};
+		'abcdefghijklmnopqrst'.split('').forEach(function (letter) {
+			test3[letter] = letter;
+		});
+		if (Object.keys(Object.assign({}, test3)).join('') !==
+				'abcdefghijklmnopqrst') {
+			return false;
+		}
+
+		return true;
+	} catch (err) {
+		// We don't expect any of the above to throw, but better to be safe.
+		return false;
+	}
+}
+
+module.exports = shouldUseNative() ? Object.assign : function (target, source) {
+	var from;
+	var to = toObject(target);
+	var symbols;
+
+	for (var s = 1; s < arguments.length; s++) {
+		from = Object(arguments[s]);
+
+		for (var key in from) {
+			if (hasOwnProperty.call(from, key)) {
+				to[key] = from[key];
+			}
+		}
+
+		if (getOwnPropertySymbols) {
+			symbols = getOwnPropertySymbols(from);
+			for (var i = 0; i < symbols.length; i++) {
+				if (propIsEnumerable.call(from, symbols[i])) {
+					to[symbols[i]] = from[symbols[i]];
+				}
+			}
+		}
+	}
+
+	return to;
+};
diff --git a/server/node_modules/object-assign/license b/server/node_modules/object-assign/license
new file mode 100644
index 0000000..654d0bf
--- /dev/null
+++ b/server/node_modules/object-assign/license
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/object-assign/package.json b/server/node_modules/object-assign/package.json
new file mode 100644
index 0000000..503eb1e
--- /dev/null
+++ b/server/node_modules/object-assign/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "object-assign",
+  "version": "4.1.1",
+  "description": "ES2015 `Object.assign()` ponyfill",
+  "license": "MIT",
+  "repository": "sindresorhus/object-assign",
+  "author": {
+    "name": "Sindre Sorhus",
+    "email": "sindresorhus@gmail.com",
+    "url": "sindresorhus.com"
+  },
+  "engines": {
+    "node": ">=0.10.0"
+  },
+  "scripts": {
+    "test": "xo && ava",
+    "bench": "matcha bench.js"
+  },
+  "files": [
+    "index.js"
+  ],
+  "keywords": [
+    "object",
+    "assign",
+    "extend",
+    "properties",
+    "es2015",
+    "ecmascript",
+    "harmony",
+    "ponyfill",
+    "prollyfill",
+    "polyfill",
+    "shim",
+    "browser"
+  ],
+  "devDependencies": {
+    "ava": "^0.16.0",
+    "lodash": "^4.16.4",
+    "matcha": "^0.7.0",
+    "xo": "^0.16.0"
+  }
+}
diff --git a/server/node_modules/object-assign/readme.md b/server/node_modules/object-assign/readme.md
new file mode 100644
index 0000000..1be09d3
--- /dev/null
+++ b/server/node_modules/object-assign/readme.md
@@ -0,0 +1,61 @@
+# object-assign [![Build Status](https://travis-ci.org/sindresorhus/object-assign.svg?branch=master)](https://travis-ci.org/sindresorhus/object-assign)
+
+> ES2015 [`Object.assign()`](http://www.2ality.com/2014/01/object-assign.html) [ponyfill](https://ponyfill.com)
+
+
+## Use the built-in
+
+Node.js 4 and up, as well as every evergreen browser (Chrome, Edge, Firefox, Opera, Safari),
+support `Object.assign()` :tada:. If you target only those environments, then by all
+means, use `Object.assign()` instead of this package.
+
+
+## Install
+
+```
+$ npm install --save object-assign
+```
+
+
+## Usage
+
+```js
+const objectAssign = require('object-assign');
+
+objectAssign({foo: 0}, {bar: 1});
+//=> {foo: 0, bar: 1}
+
+// multiple sources
+objectAssign({foo: 0}, {bar: 1}, {baz: 2});
+//=> {foo: 0, bar: 1, baz: 2}
+
+// overwrites equal keys
+objectAssign({foo: 0}, {foo: 1}, {foo: 2});
+//=> {foo: 2}
+
+// ignores null and undefined sources
+objectAssign({foo: 0}, null, {bar: 1}, undefined);
+//=> {foo: 0, bar: 1}
+```
+
+
+## API
+
+### objectAssign(target, [source, ...])
+
+Assigns enumerable own properties of `source` objects to the `target` object and returns the `target` object. Additional `source` objects will overwrite previous ones.
+
+
+## Resources
+
+- [ES2015 spec - Object.assign](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.assign)
+
+
+## Related
+
+- [deep-assign](https://github.com/sindresorhus/deep-assign) - Recursive `Object.assign()`
+
+
+## License
+
+MIT © [Sindre Sorhus](https://sindresorhus.com)
diff --git a/server/node_modules/object-inspect/.eslintrc b/server/node_modules/object-inspect/.eslintrc
new file mode 100644
index 0000000..21f9039
--- /dev/null
+++ b/server/node_modules/object-inspect/.eslintrc
@@ -0,0 +1,53 @@
+{
+    "root": true,
+    "extends": "@ljharb",
+    "rules": {
+        "complexity": 0,
+        "func-style": [2, "declaration"],
+        "indent": [2, 4],
+        "max-lines": 1,
+        "max-lines-per-function": 1,
+        "max-params": [2, 4],
+        "max-statements": 0,
+        "max-statements-per-line": [2, { "max": 2 }],
+        "no-magic-numbers": 0,
+        "no-param-reassign": 1,
+        "strict": 0, // TODO
+    },
+    "overrides": [
+        {
+            "files": ["test/**", "test-*", "example/**"],
+            "extends": "@ljharb/eslint-config/tests",
+            "rules": {
+              "id-length": 0,
+            },
+        },
+        {
+            "files": ["example/**"],
+            "rules": {
+                "no-console": 0,
+            },
+        },
+        {
+            "files": ["test/browser/**"],
+            "env": {
+                "browser": true,
+            },
+        },
+        {
+            "files": ["test/bigint*"],
+            "rules": {
+                "new-cap": [2, { "capIsNewExceptions": ["BigInt"] }],
+            },
+        },
+        {
+            "files": "index.js",
+            "globals": {
+                "HTMLElement": false,
+            },
+            "rules": {
+                "no-use-before-define": 1,
+            },
+        },
+    ],
+}
diff --git a/server/node_modules/object-inspect/.github/FUNDING.yml b/server/node_modules/object-inspect/.github/FUNDING.yml
new file mode 100644
index 0000000..730276b
--- /dev/null
+++ b/server/node_modules/object-inspect/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/object-inspect
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/object-inspect/.nycrc b/server/node_modules/object-inspect/.nycrc
new file mode 100644
index 0000000..58a5db7
--- /dev/null
+++ b/server/node_modules/object-inspect/.nycrc
@@ -0,0 +1,13 @@
+{
+  "all": true,
+  "check-coverage": false,
+  "instrumentation": false,
+  "sourceMap": false,
+  "reporter": ["text-summary", "text", "html", "json"],
+  "exclude": [
+    "coverage",
+    "example",
+    "test",
+    "test-core-js.js"
+  ]
+}
diff --git a/server/node_modules/object-inspect/CHANGELOG.md b/server/node_modules/object-inspect/CHANGELOG.md
new file mode 100644
index 0000000..bdf9002
--- /dev/null
+++ b/server/node_modules/object-inspect/CHANGELOG.md
@@ -0,0 +1,424 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.13.4](https://github.com/inspect-js/object-inspect/compare/v1.13.3...v1.13.4) - 2025-02-04
+
+### Commits
+
+- [Fix] avoid being fooled by a `Symbol.toStringTag` [`fa5870d`](https://github.com/inspect-js/object-inspect/commit/fa5870da468a525d2f20193700f70752f506cbf7)
+- [Tests] fix tests in node v6.0 - v6.4 [`2abfe1b`](https://github.com/inspect-js/object-inspect/commit/2abfe1bc3c69f9293c07c5cd65a9d7d87a628b84)
+- [Dev Deps] update `es-value-fixtures`, `for-each`, `has-symbols` [`3edfb01`](https://github.com/inspect-js/object-inspect/commit/3edfb01cc8cce220fba0dfdfe2dc8bc955758cdd)
+
+## [v1.13.3](https://github.com/inspect-js/object-inspect/compare/v1.13.2...v1.13.3) - 2024-11-09
+
+### Commits
+
+- [actions] split out node 10-20, and 20+ [`44395a8`](https://github.com/inspect-js/object-inspect/commit/44395a8fc1deda6718a5e125e86b9ffcaa1c7580)
+- [Fix] `quoteStyle`: properly escape only the containing quotes [`5137f8f`](https://github.com/inspect-js/object-inspect/commit/5137f8f7bea69a7fc671bb683fd35f244f38fc52)
+- [Refactor] clean up `quoteStyle` code [`450680c`](https://github.com/inspect-js/object-inspect/commit/450680cd50de4e689ee3b8e1d6db3a1bcf3fc18c)
+- [Tests] add `quoteStyle` escaping tests [`e997c59`](https://github.com/inspect-js/object-inspect/commit/e997c595aeaea84fd98ca35d7e1c3b5ab3ae26e0)
+- [Dev Deps] update `auto-changelog`, `es-value-fixtures`, `tape` [`d5a469c`](https://github.com/inspect-js/object-inspect/commit/d5a469c99ec07ccaeafc36ac4b36a93285086d48)
+- [Tests] replace `aud` with `npm audit` [`fb7815f`](https://github.com/inspect-js/object-inspect/commit/fb7815f9b72cae277a04f65bbb0543f85b88be62)
+- [Dev Deps] update `mock-property` [`11c817b`](https://github.com/inspect-js/object-inspect/commit/11c817bf10392aa017755962ba6bc89d731359ee)
+
+## [v1.13.2](https://github.com/inspect-js/object-inspect/compare/v1.13.1...v1.13.2) - 2024-06-21
+
+### Commits
+
+- [readme] update badges [`8a51e6b`](https://github.com/inspect-js/object-inspect/commit/8a51e6bedaf389ec40cc4659e9df53e8543d176e)
+- [Dev Deps] update `@ljharb/eslint-config`, `tape` [`ef05f58`](https://github.com/inspect-js/object-inspect/commit/ef05f58c9761a41416ab907299bf0fa79517014b)
+- [Dev Deps] update `error-cause`, `has-tostringtag`, `tape` [`c0c6c26`](https://github.com/inspect-js/object-inspect/commit/c0c6c26c44cee6671f7c5d43d2b91d27c5c00d90)
+- [Fix] Don't throw when `global` is not defined [`d4d0965`](https://github.com/inspect-js/object-inspect/commit/d4d096570f7dbd0e03266a96de11d05eb7b63e0f)
+- [meta] add missing `engines.node` [`17a352a`](https://github.com/inspect-js/object-inspect/commit/17a352af6fe1ba6b70a19081674231eb1a50c940)
+- [Dev Deps] update `globalthis` [`9c08884`](https://github.com/inspect-js/object-inspect/commit/9c08884aa662a149e2f11403f413927736b97da7)
+- [Dev Deps] update `error-cause` [`6af352d`](https://github.com/inspect-js/object-inspect/commit/6af352d7c3929a4cc4c55768c27bf547a5e900f4)
+- [Dev Deps] update `npmignore` [`94e617d`](https://github.com/inspect-js/object-inspect/commit/94e617d38831722562fa73dff4c895746861d267)
+- [Dev Deps] update `mock-property` [`2ac24d7`](https://github.com/inspect-js/object-inspect/commit/2ac24d7e58cd388ad093c33249e413e05bbfd6c3)
+- [Dev Deps] update `tape` [`46125e5`](https://github.com/inspect-js/object-inspect/commit/46125e58f1d1dcfb170ed3d1ea69da550ea8d77b)
+
+## [v1.13.1](https://github.com/inspect-js/object-inspect/compare/v1.13.0...v1.13.1) - 2023-10-19
+
+### Commits
+
+- [Fix] in IE 8, global can !== window despite them being prototypes of each other [`30d0859`](https://github.com/inspect-js/object-inspect/commit/30d0859dc4606cf75c2410edcd5d5c6355f8d372)
+
+## [v1.13.0](https://github.com/inspect-js/object-inspect/compare/v1.12.3...v1.13.0) - 2023-10-14
+
+### Commits
+
+- [New] add special handling for the global object [`431bab2`](https://github.com/inspect-js/object-inspect/commit/431bab21a490ee51d35395966a504501e8c685da)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud`, `tape` [`fd4f619`](https://github.com/inspect-js/object-inspect/commit/fd4f6193562b4b0e95dcf5c0201b4e8cbbc4f58d)
+- [Dev Deps] update `mock-property`, `tape` [`b453f6c`](https://github.com/inspect-js/object-inspect/commit/b453f6ceeebf8a1b738a1029754092e0367a4134)
+- [Dev Deps] update `error-cause` [`e8ffc57`](https://github.com/inspect-js/object-inspect/commit/e8ffc577d73b92bb6a4b00c44f14e3319e374888)
+- [Dev Deps] update `tape` [`054b8b9`](https://github.com/inspect-js/object-inspect/commit/054b8b9b98633284cf989e582450ebfbbe53503c)
+- [Dev Deps] temporarily remove `aud` due to breaking change in transitive deps [`2476845`](https://github.com/inspect-js/object-inspect/commit/2476845e0678dd290c541c81cd3dec8420782c52)
+- [Dev Deps] pin `glob`, since v10.3.8+ requires a broken `jackspeak` [`383fa5e`](https://github.com/inspect-js/object-inspect/commit/383fa5eebc0afd705cc778a4b49d8e26452e49a8)
+- [Dev Deps] pin `jackspeak` since 2.1.2+ depends on npm aliases, which kill the install process in npm < 6 [`68c244c`](https://github.com/inspect-js/object-inspect/commit/68c244c5174cdd877e5dcb8ee90aa3f44b2f25be)
+
+## [v1.12.3](https://github.com/inspect-js/object-inspect/compare/v1.12.2...v1.12.3) - 2023-01-12
+
+### Commits
+
+- [Fix] in eg FF 24, collections lack forEach [`75fc226`](https://github.com/inspect-js/object-inspect/commit/75fc22673c82d45f28322b1946bb0eb41b672b7f)
+- [actions] update rebase action to use reusable workflow [`250a277`](https://github.com/inspect-js/object-inspect/commit/250a277a095e9dacc029ab8454dcfc15de549dcd)
+- [Dev Deps] update `aud`, `es-value-fixtures`, `tape` [`66a19b3`](https://github.com/inspect-js/object-inspect/commit/66a19b3209ccc3c5ef4b34c3cb0160e65d1ce9d5)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud`, `error-cause` [`c43d332`](https://github.com/inspect-js/object-inspect/commit/c43d3324b48384a16fd3dc444e5fc589d785bef3)
+- [Tests] add `@pkgjs/support` to `postlint` [`e2618d2`](https://github.com/inspect-js/object-inspect/commit/e2618d22a7a3fa361b6629b53c1752fddc9c4d80)
+
+## [v1.12.2](https://github.com/inspect-js/object-inspect/compare/v1.12.1...v1.12.2) - 2022-05-26
+
+### Commits
+
+- [Fix] use `util.inspect` for a custom inspection symbol method [`e243bf2`](https://github.com/inspect-js/object-inspect/commit/e243bf2eda6c4403ac6f1146fddb14d12e9646c1)
+- [meta] add support info [`ca20ba3`](https://github.com/inspect-js/object-inspect/commit/ca20ba35713c17068ca912a86c542f5e8acb656c)
+- [Fix] ignore `cause` in node v16.9 and v16.10 where it has a bug [`86aa553`](https://github.com/inspect-js/object-inspect/commit/86aa553a4a455562c2c56f1540f0bf857b9d314b)
+
+## [v1.12.1](https://github.com/inspect-js/object-inspect/compare/v1.12.0...v1.12.1) - 2022-05-21
+
+### Commits
+
+- [Tests] use `mock-property` [`4ec8893`](https://github.com/inspect-js/object-inspect/commit/4ec8893ea9bfd28065ca3638cf6762424bf44352)
+- [meta] use `npmignore` to autogenerate an npmignore file [`07f868c`](https://github.com/inspect-js/object-inspect/commit/07f868c10bd25a9d18686528339bb749c211fc9a)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `auto-changelog`, `tape` [`b05244b`](https://github.com/inspect-js/object-inspect/commit/b05244b4f331e00c43b3151bc498041be77ccc91)
+- [Dev Deps] update `@ljharb/eslint-config`, `error-cause`, `es-value-fixtures`, `functions-have-names`, `tape` [`d037398`](https://github.com/inspect-js/object-inspect/commit/d037398dcc5d531532e4c19c4a711ed677f579c1)
+- [Fix] properly handle callable regexes in older engines [`848fe48`](https://github.com/inspect-js/object-inspect/commit/848fe48bd6dd0064ba781ee6f3c5e54a94144c37)
+
+## [v1.12.0](https://github.com/inspect-js/object-inspect/compare/v1.11.1...v1.12.0) - 2021-12-18
+
+### Commits
+
+- [New] add `numericSeparator` boolean option [`2d2d537`](https://github.com/inspect-js/object-inspect/commit/2d2d537f5359a4300ce1c10241369f8024f89e11)
+- [Robustness] cache more prototype methods [`191533d`](https://github.com/inspect-js/object-inspect/commit/191533da8aec98a05eadd73a5a6e979c9c8653e8)
+- [New] ensure an Error’s `cause` is displayed [`53bc2ce`](https://github.com/inspect-js/object-inspect/commit/53bc2cee4e5a9cc4986f3cafa22c0685f340715e)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config` [`bc164b6`](https://github.com/inspect-js/object-inspect/commit/bc164b6e2e7d36b263970f16f54de63048b84a36)
+- [Robustness] cache `RegExp.prototype.test` [`a314ab8`](https://github.com/inspect-js/object-inspect/commit/a314ab8271b905cbabc594c82914d2485a8daf12)
+- [meta] fix auto-changelog settings [`5ed0983`](https://github.com/inspect-js/object-inspect/commit/5ed0983be72f73e32e2559997517a95525c7e20d)
+
+## [v1.11.1](https://github.com/inspect-js/object-inspect/compare/v1.11.0...v1.11.1) - 2021-12-05
+
+### Commits
+
+- [meta] add `auto-changelog` [`7dbdd22`](https://github.com/inspect-js/object-inspect/commit/7dbdd228401d6025d8b7391476d88aee9ea9bbdf)
+- [actions] reuse common workflows [`c8823bc`](https://github.com/inspect-js/object-inspect/commit/c8823bc0a8790729680709d45fb6e652432e91aa)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `safe-publish-latest`, `tape` [`7532b12`](https://github.com/inspect-js/object-inspect/commit/7532b120598307497b712890f75af8056f6d37a6)
+- [Refactor] use `has-tostringtag` to behave correctly in the presence of symbol shams [`94abb5d`](https://github.com/inspect-js/object-inspect/commit/94abb5d4e745bf33253942dea86b3e538d2ff6c6)
+- [actions] update codecov uploader [`5ed5102`](https://github.com/inspect-js/object-inspect/commit/5ed51025267a00e53b1341357315490ac4eb0874)
+- [Dev Deps] update `eslint`, `tape` [`37b2ad2`](https://github.com/inspect-js/object-inspect/commit/37b2ad26c08d94bfd01d5d07069a0b28ef4e2ad7)
+- [meta] add `sideEffects` flag [`d341f90`](https://github.com/inspect-js/object-inspect/commit/d341f905ef8bffa6a694cda6ddc5ba343532cd4f)
+
+## [v1.11.0](https://github.com/inspect-js/object-inspect/compare/v1.10.3...v1.11.0) - 2021-07-12
+
+### Commits
+
+- [New] `customInspect`: add `symbol` option, to mimic modern util.inspect behavior [`e973a6e`](https://github.com/inspect-js/object-inspect/commit/e973a6e21f8140c5837cf25e9d89bdde88dc3120)
+- [Dev Deps] update `eslint` [`05f1cb3`](https://github.com/inspect-js/object-inspect/commit/05f1cb3cbcfe1f238e8b51cf9bc294305b7ed793)
+
+## [v1.10.3](https://github.com/inspect-js/object-inspect/compare/v1.10.2...v1.10.3) - 2021-05-07
+
+### Commits
+
+- [Fix] handle core-js Symbol shams [`4acfc2c`](https://github.com/inspect-js/object-inspect/commit/4acfc2c4b503498759120eb517abad6d51c9c5d6)
+- [readme] update badges [`95c323a`](https://github.com/inspect-js/object-inspect/commit/95c323ad909d6cbabb95dd6015c190ba6db9c1f2)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud` [`cb38f48`](https://github.com/inspect-js/object-inspect/commit/cb38f485de6ec7a95109b5a9bbd0a1deba2f6611)
+
+## [v1.10.2](https://github.com/inspect-js/object-inspect/compare/v1.10.1...v1.10.2) - 2021-04-17
+
+### Commits
+
+- [Fix] use a robust check for a boxed Symbol [`87f12d6`](https://github.com/inspect-js/object-inspect/commit/87f12d6e69ce530be04659c81a4cd502943acac5)
+
+## [v1.10.1](https://github.com/inspect-js/object-inspect/compare/v1.10.0...v1.10.1) - 2021-04-17
+
+### Commits
+
+- [Fix] use a robust check for a boxed bigint [`d5ca829`](https://github.com/inspect-js/object-inspect/commit/d5ca8298b6d2e5c7b9334a5b21b96ed95d225c91)
+
+## [v1.10.0](https://github.com/inspect-js/object-inspect/compare/v1.9.0...v1.10.0) - 2021-04-17
+
+### Commits
+
+- [Tests] increase coverage [`d8abb8a`](https://github.com/inspect-js/object-inspect/commit/d8abb8a62c2f084919df994a433b346e0d87a227)
+- [actions] use `node/install` instead of `node/run`; use `codecov` action [`4bfec2e`](https://github.com/inspect-js/object-inspect/commit/4bfec2e30aaef6ddef6cbb1448306f9f8b9520b7)
+- [New] respect `Symbol.toStringTag` on objects [`799b58f`](https://github.com/inspect-js/object-inspect/commit/799b58f536a45e4484633a8e9daeb0330835f175)
+- [Fix] do not allow Symbol.toStringTag to masquerade as builtins [`d6c5b37`](https://github.com/inspect-js/object-inspect/commit/d6c5b37d7e94427796b82432fb0c8964f033a6ab)
+- [New] add `WeakRef` support [`b6d898e`](https://github.com/inspect-js/object-inspect/commit/b6d898ee21868c780a7ee66b28532b5b34ed7f09)
+- [meta] do not publish github action workflow files [`918cdfc`](https://github.com/inspect-js/object-inspect/commit/918cdfc4b6fe83f559ff6ef04fe66201e3ff5cbd)
+- [meta] create `FUNDING.yml` [`0bb5fc5`](https://github.com/inspect-js/object-inspect/commit/0bb5fc516dbcd2cd728bd89cee0b580acc5ce301)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `tape` [`22c8dc0`](https://github.com/inspect-js/object-inspect/commit/22c8dc0cac113d70f4781e49a950070923a671be)
+- [meta] use `prepublishOnly` script for npm 7+ [`e52ee09`](https://github.com/inspect-js/object-inspect/commit/e52ee09e8050b8dbac94ef57f786675567728223)
+- [Dev Deps] update `eslint` [`7c4e6fd`](https://github.com/inspect-js/object-inspect/commit/7c4e6fdedcd27cc980e13c9ad834d05a96f3d40c)
+
+## [v1.9.0](https://github.com/inspect-js/object-inspect/compare/v1.8.0...v1.9.0) - 2020-11-30
+
+### Commits
+
+- [Tests] migrate tests to Github Actions [`d262251`](https://github.com/inspect-js/object-inspect/commit/d262251e13e16d3490b5473672f6b6d6ff86675d)
+- [New] add enumerable own Symbols to plain object output [`ee60c03`](https://github.com/inspect-js/object-inspect/commit/ee60c033088cff9d33baa71e59a362a541b48284)
+- [Tests] add passing tests [`01ac3e4`](https://github.com/inspect-js/object-inspect/commit/01ac3e4b5a30f97875a63dc9b1416b3bd626afc9)
+- [actions] add "Require Allow Edits" action [`c2d7746`](https://github.com/inspect-js/object-inspect/commit/c2d774680cde4ca4af332d84d4121b26f798ba9e)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `core-js` [`70058de`](https://github.com/inspect-js/object-inspect/commit/70058de1579fc54d1d15ed6c2dbe246637ce70ff)
+- [Fix] hex characters in strings should be uppercased, to match node `assert` [`6ab8faa`](https://github.com/inspect-js/object-inspect/commit/6ab8faaa0abc08fe7a8e2afd8b39c6f1f0e00113)
+- [Tests] run `nyc` on all tests [`4c47372`](https://github.com/inspect-js/object-inspect/commit/4c473727879ddc8e28b599202551ddaaf07b6210)
+- [Tests] node 0.8 has an unpredictable property order; fix `groups` test by removing property [`f192069`](https://github.com/inspect-js/object-inspect/commit/f192069a978a3b60e6f0e0d45ac7df260ab9a778)
+- [New] add enumerable properties to Function inspect result, per node’s `assert` [`fd38e1b`](https://github.com/inspect-js/object-inspect/commit/fd38e1bc3e2a1dc82091ce3e021917462eee64fc)
+- [Tests] fix tests for node < 10, due to regex match `groups` [`2ac6462`](https://github.com/inspect-js/object-inspect/commit/2ac6462cc4f72eaa0b63a8cfee9aabe3008b2330)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config` [`44b59e2`](https://github.com/inspect-js/object-inspect/commit/44b59e2676a7f825ef530dfd19dafb599e3b9456)
+- [Robustness] cache `Symbol.prototype.toString` [`f3c2074`](https://github.com/inspect-js/object-inspect/commit/f3c2074d8f32faf8292587c07c9678ea931703dd)
+- [Dev Deps] update `eslint` [`9411294`](https://github.com/inspect-js/object-inspect/commit/94112944b9245e3302e25453277876402d207e7f)
+- [meta] `require-allow-edits` no longer requires an explicit github token [`36c0220`](https://github.com/inspect-js/object-inspect/commit/36c02205de3c2b0e84d53777c5c9fd54a36c48ab)
+- [actions] update rebase checkout action to v2 [`55a39a6`](https://github.com/inspect-js/object-inspect/commit/55a39a64e944f19c6a7d8efddf3df27700f20d14)
+- [actions] switch Automatic Rebase workflow to `pull_request_target` event [`f59fd3c`](https://github.com/inspect-js/object-inspect/commit/f59fd3cf406c3a7c7ece140904a80bbc6bacfcca)
+- [Dev Deps] update `eslint` [`a492bec`](https://github.com/inspect-js/object-inspect/commit/a492becec644b0155c9c4bc1caf6f9fac11fb2c7)
+
+## [v1.8.0](https://github.com/inspect-js/object-inspect/compare/v1.7.0...v1.8.0) - 2020-06-18
+
+### Fixed
+
+- [New] add `indent` option [`#27`](https://github.com/inspect-js/object-inspect/issues/27)
+
+### Commits
+
+- [Tests] add codecov [`4324cbb`](https://github.com/inspect-js/object-inspect/commit/4324cbb1a2bd7710822a4151ff373570db22453e)
+- [New] add `maxStringLength` option [`b3995cb`](https://github.com/inspect-js/object-inspect/commit/b3995cb71e15b5ee127a3094c43994df9d973502)
+- [New] add `customInspect` option, to disable custom inspect methods [`28b9179`](https://github.com/inspect-js/object-inspect/commit/28b9179ee802bb3b90810100c11637db90c2fb6d)
+- [Tests] add Date and RegExp tests [`3b28eca`](https://github.com/inspect-js/object-inspect/commit/3b28eca57b0367aeadffac604ea09e8bdae7d97b)
+- [actions] add automatic rebasing / merge commit blocking [`0d9c6c0`](https://github.com/inspect-js/object-inspect/commit/0d9c6c044e83475ff0bfffb9d35b149834c83a2e)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `core-js`, `tape`; add `aud` [`7c204f2`](https://github.com/inspect-js/object-inspect/commit/7c204f22b9e41bc97147f4d32d4cb045b17769a6)
+- [readme] fix repo URLs, remove testling [`34ca9a0`](https://github.com/inspect-js/object-inspect/commit/34ca9a0dabfe75bd311f806a326fadad029909a3)
+- [Fix] when truncating a deep array, note it as `[Array]` instead of just `[Object]` [`f74c82d`](https://github.com/inspect-js/object-inspect/commit/f74c82dd0b35386445510deb250f34c41be3ec0e)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `tape` [`1a8a5ea`](https://github.com/inspect-js/object-inspect/commit/1a8a5ea069ea2bee89d77caedad83ffa23d35711)
+- [Fix] do not be fooled by a function’s own `toString` method [`7cb5c65`](https://github.com/inspect-js/object-inspect/commit/7cb5c657a976f94715c19c10556a30f15bb7d5d7)
+- [patch] indicate explicitly that anon functions are anonymous, to match node [`81ebdd4`](https://github.com/inspect-js/object-inspect/commit/81ebdd4215005144074bbdff3f6bafa01407910a)
+- [Dev Deps] loosen the `core-js` dep [`e7472e8`](https://github.com/inspect-js/object-inspect/commit/e7472e8e242117670560bd995830c2a4d12080f5)
+- [Dev Deps] update `tape` [`699827e`](https://github.com/inspect-js/object-inspect/commit/699827e6b37258b5203c33c78c009bf4b0e6a66d)
+- [meta] add `safe-publish-latest` [`c5d2868`](https://github.com/inspect-js/object-inspect/commit/c5d2868d6eb33c472f37a20f89ceef2787046088)
+- [Dev Deps] update `@ljharb/eslint-config` [`9199501`](https://github.com/inspect-js/object-inspect/commit/919950195d486114ccebacbdf9d74d7f382693b0)
+
+## [v1.7.0](https://github.com/inspect-js/object-inspect/compare/v1.6.0...v1.7.0) - 2019-11-10
+
+### Commits
+
+- [Tests] use shared travis-ci configs [`19899ed`](https://github.com/inspect-js/object-inspect/commit/19899edbf31f4f8809acf745ce34ad1ce1bfa63b)
+- [Tests] add linting [`a00f057`](https://github.com/inspect-js/object-inspect/commit/a00f057d917f66ea26dd37769c6b810ec4af97e8)
+- [Tests] lint last file [`2698047`](https://github.com/inspect-js/object-inspect/commit/2698047b58af1e2e88061598ef37a75f228dddf6)
+- [Tests] up to `node` `v12.7`, `v11.15`, `v10.16`, `v8.16`, `v6.17` [`589e87a`](https://github.com/inspect-js/object-inspect/commit/589e87a99cadcff4b600e6a303418e9d922836e8)
+- [New] add support for `WeakMap` and `WeakSet` [`3ddb3e4`](https://github.com/inspect-js/object-inspect/commit/3ddb3e4e0c8287130c61a12e0ed9c104b1549306)
+- [meta] clean up license so github can detect it properly [`27527bb`](https://github.com/inspect-js/object-inspect/commit/27527bb801520c9610c68cc3b55d6f20a2bee56d)
+- [Tests] cover `util.inspect.custom` [`36d47b9`](https://github.com/inspect-js/object-inspect/commit/36d47b9c59056a57ef2f1491602c726359561800)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `core-js`, `tape` [`b614eaa`](https://github.com/inspect-js/object-inspect/commit/b614eaac901da0e5c69151f534671f990a94cace)
+- [Tests] fix coverage thresholds [`7b7b176`](https://github.com/inspect-js/object-inspect/commit/7b7b176e15f8bd6e8b2f261ff5a493c2fe78d9c2)
+- [Tests] bigint tests now can run on unflagged node [`063af31`](https://github.com/inspect-js/object-inspect/commit/063af31ce9cd13c202e3b67c07ba06dc9b7c0f81)
+- [Refactor] add early bailout to `isMap` and `isSet` checks [`fc51047`](https://github.com/inspect-js/object-inspect/commit/fc5104714a3671d37e225813db79470d6335683b)
+- [meta] add `funding` field [`7f9953a`](https://github.com/inspect-js/object-inspect/commit/7f9953a113eec7b064a6393cf9f90ba15f1d131b)
+- [Tests] Fix invalid strict-mode syntax with hexadecimal [`a8b5425`](https://github.com/inspect-js/object-inspect/commit/a8b542503b4af1599a275209a1a99f5fdedb1ead)
+- [Dev Deps] update `@ljharb/eslint-config` [`98df157`](https://github.com/inspect-js/object-inspect/commit/98df1577314d9188a3fc3f17fdcf2fba697ae1bd)
+- add copyright to LICENSE [`bb69fd0`](https://github.com/inspect-js/object-inspect/commit/bb69fd017a062d299e44da1f9b2c7dcd67f621e6)
+- [Tests] use `npx aud` in `posttest` [`4838353`](https://github.com/inspect-js/object-inspect/commit/4838353593974cf7f905b9ef04c03c094f0cdbe2)
+- [Tests] move `0.6` to allowed failures, because it won‘t build on travis [`1bff32a`](https://github.com/inspect-js/object-inspect/commit/1bff32aa52e8aea687f0856b28ba754b3e43ebf7)
+
+## [v1.6.0](https://github.com/inspect-js/object-inspect/compare/v1.5.0...v1.6.0) - 2018-05-02
+
+### Commits
+
+- [New] add support for boxed BigInt primitives [`356c66a`](https://github.com/inspect-js/object-inspect/commit/356c66a410e7aece7162c8319880a5ef647beaa9)
+- [Tests] up to `node` `v10.0`, `v9.11`, `v8.11`, `v6.14`, `v4.9` [`c77b65b`](https://github.com/inspect-js/object-inspect/commit/c77b65bba593811b906b9ec57561c5cba92e2db3)
+- [New] Add support for upcoming `BigInt` [`1ac548e`](https://github.com/inspect-js/object-inspect/commit/1ac548e4b27e26466c28c9a5e63e5d4e0591c31f)
+- [Tests] run bigint tests in CI with --harmony-bigint flag [`d31b738`](https://github.com/inspect-js/object-inspect/commit/d31b73831880254b5c6cf5691cda9a149fbc5f04)
+- [Dev Deps] update `core-js`, `tape` [`ff9eff6`](https://github.com/inspect-js/object-inspect/commit/ff9eff67113341ee1aaf80c1c22d683f43bfbccf)
+- [Docs] fix example to use `safer-buffer` [`48cae12`](https://github.com/inspect-js/object-inspect/commit/48cae12a73ec6cacc955175bc56bbe6aee6a211f)
+
+## [v1.5.0](https://github.com/inspect-js/object-inspect/compare/v1.4.1...v1.5.0) - 2017-12-25
+
+### Commits
+
+- [New] add `quoteStyle` option [`f5a72d2`](https://github.com/inspect-js/object-inspect/commit/f5a72d26edb3959b048f74c056ca7100a6b091e4)
+- [Tests] add more test coverage [`30ebe4e`](https://github.com/inspect-js/object-inspect/commit/30ebe4e1fa943b99ecbb85be7614256d536e2759)
+- [Tests] require 0.6 to pass [`99a008c`](https://github.com/inspect-js/object-inspect/commit/99a008ccace189a60fd7da18bf00e32c9572b980)
+
+## [v1.4.1](https://github.com/inspect-js/object-inspect/compare/v1.4.0...v1.4.1) - 2017-12-19
+
+### Commits
+
+- [Tests] up to `node` `v9.3`, `v8.9`, `v6.12` [`6674476`](https://github.com/inspect-js/object-inspect/commit/6674476cc56acaac1bde96c84fed5ef631911906)
+- [Fix] `inspect(Object(-0))` should be “Object(-0)”, not “Object(0)” [`d0a031f`](https://github.com/inspect-js/object-inspect/commit/d0a031f1cbb3024ee9982bfe364dd18a7e4d1bd3)
+
+## [v1.4.0](https://github.com/inspect-js/object-inspect/compare/v1.3.0...v1.4.0) - 2017-10-24
+
+### Commits
+
+- [Tests] add `npm run coverage` [`3b48fb2`](https://github.com/inspect-js/object-inspect/commit/3b48fb25db037235eeb808f0b2830aad7aa36f70)
+- [Tests] remove commented-out osx builds [`71e24db`](https://github.com/inspect-js/object-inspect/commit/71e24db8ad6ee3b9b381c5300b0475f2ba595a73)
+- [New] add support for `util.inspect.custom`, in node only. [`20cca77`](https://github.com/inspect-js/object-inspect/commit/20cca7762d7e17f15b21a90793dff84acce155df)
+- [Tests] up to `node` `v8.6`; use `nvm install-latest-npm` to ensure new npm doesn’t break old node [`252952d`](https://github.com/inspect-js/object-inspect/commit/252952d230d8065851dd3d4d5fe8398aae068529)
+- [Tests] up to `node` `v8.8` [`4aa868d`](https://github.com/inspect-js/object-inspect/commit/4aa868d3a62914091d489dd6ec6eed194ee67cd3)
+- [Dev Deps] update `core-js`, `tape` [`59483d1`](https://github.com/inspect-js/object-inspect/commit/59483d1df418f852f51fa0db7b24aa6b0209a27a)
+
+## [v1.3.0](https://github.com/inspect-js/object-inspect/compare/v1.2.2...v1.3.0) - 2017-07-31
+
+### Fixed
+
+- [Fix] Map/Set: work around core-js bug < v2.5.0 [`#9`](https://github.com/inspect-js/object-inspect/issues/9)
+
+### Commits
+
+- [New] add support for arrays with additional object keys [`0d19937`](https://github.com/inspect-js/object-inspect/commit/0d199374ee37959e51539616666f420ccb29acb9)
+- [Tests] up to `node` `v8.2`, `v7.10`, `v6.11`; fix new npm breaking on older nodes [`e24784a`](https://github.com/inspect-js/object-inspect/commit/e24784a90c49117787157a12a63897c49cf89bbb)
+- Only apps should have lockfiles [`c6faebc`](https://github.com/inspect-js/object-inspect/commit/c6faebcb2ee486a889a4a1c4d78c0776c7576185)
+- [Dev Deps] update `tape` [`7345a0a`](https://github.com/inspect-js/object-inspect/commit/7345a0aeba7e91b888a079c10004d17696a7f586)
+
+## [v1.2.2](https://github.com/inspect-js/object-inspect/compare/v1.2.1...v1.2.2) - 2017-03-24
+
+### Commits
+
+- [Tests] up to `node` `v7.7`, `v6.10`, `v4.8`; improve test matrix [`a2ddc15`](https://github.com/inspect-js/object-inspect/commit/a2ddc15a1f2c65af18076eea1c0eb9cbceb478a0)
+- [Tests] up to `node` `v7.0`, `v6.9`, `v5.12`, `v4.6`, `io.js` `v3.3`; improve test matrix [`a48949f`](https://github.com/inspect-js/object-inspect/commit/a48949f6b574b2d4d2298109d8e8d0eb3e7a83e7)
+- [Performance] check for primitive types as early as possible. [`3b8092a`](https://github.com/inspect-js/object-inspect/commit/3b8092a2a4deffd0575f94334f00194e2d48dad3)
+- [Refactor] remove unneeded `else`s. [`7255034`](https://github.com/inspect-js/object-inspect/commit/725503402e08de4f96f6bf2d8edef44ac36f26b6)
+- [Refactor] avoid recreating `lowbyte` function every time. [`81edd34`](https://github.com/inspect-js/object-inspect/commit/81edd3475bd15bdd18e84de7472033dcf5004aaa)
+- [Fix] differentiate -0 from 0 [`521d345`](https://github.com/inspect-js/object-inspect/commit/521d3456b009da7bf1c5785c8a9df5a9f8718264)
+- [Refactor] move object key gathering into separate function [`aca6265`](https://github.com/inspect-js/object-inspect/commit/aca626536eaeef697196c6e9db3e90e7e0355b6a)
+- [Refactor] consolidate wrapping logic for boxed primitives into a function. [`4e440cd`](https://github.com/inspect-js/object-inspect/commit/4e440cd9065df04802a2a1dead03f48c353ca301)
+- [Robustness] use `typeof` instead of comparing to literal `undefined` [`5ca6f60`](https://github.com/inspect-js/object-inspect/commit/5ca6f601937506daff8ed2fcf686363b55807b69)
+- [Refactor] consolidate Map/Set notations. [`4e576e5`](https://github.com/inspect-js/object-inspect/commit/4e576e5d7ed2f9ec3fb7f37a0d16732eb10758a9)
+- [Tests] ensure that this function remains anonymous, despite ES6 name inference. [`7540ae5`](https://github.com/inspect-js/object-inspect/commit/7540ae591278756db614fa4def55ca413150e1a3)
+- [Refactor] explicitly coerce Error objects to strings. [`7f4ca84`](https://github.com/inspect-js/object-inspect/commit/7f4ca8424ee8dc2c0ca5a422d94f7fac40327261)
+- [Refactor] split up `var` declarations for debuggability [`6f2c11e`](https://github.com/inspect-js/object-inspect/commit/6f2c11e6a85418586a00292dcec5e97683f89bc3)
+- [Robustness] cache `Object.prototype.toString` [`df44a20`](https://github.com/inspect-js/object-inspect/commit/df44a20adfccf31529d60d1df2079bfc3c836e27)
+- [Dev Deps] update `tape` [`3ec714e`](https://github.com/inspect-js/object-inspect/commit/3ec714eba57bc3f58a6eb4fca1376f49e70d300a)
+- [Dev Deps] update `tape` [`beb72d9`](https://github.com/inspect-js/object-inspect/commit/beb72d969653747d7cde300393c28755375329b0)
+
+## [v1.2.1](https://github.com/inspect-js/object-inspect/compare/v1.2.0...v1.2.1) - 2016-04-09
+
+### Fixed
+
+- [Fix] fix Boolean `false` object inspection. [`#7`](https://github.com/substack/object-inspect/pull/7)
+
+## [v1.2.0](https://github.com/inspect-js/object-inspect/compare/v1.1.0...v1.2.0) - 2016-04-09
+
+### Fixed
+
+- [New] add support for inspecting String/Number/Boolean objects. [`#6`](https://github.com/inspect-js/object-inspect/issues/6)
+
+### Commits
+
+- [Dev Deps] update `tape` [`742caa2`](https://github.com/inspect-js/object-inspect/commit/742caa262cf7af4c815d4821c8bd0129c1446432)
+
+## [v1.1.0](https://github.com/inspect-js/object-inspect/compare/1.0.2...v1.1.0) - 2015-12-14
+
+### Merged
+
+- [New] add ES6 Map/Set support. [`#4`](https://github.com/inspect-js/object-inspect/pull/4)
+
+### Fixed
+
+- [New] add ES6 Map/Set support. [`#3`](https://github.com/inspect-js/object-inspect/issues/3)
+
+### Commits
+
+- Update `travis.yml` to test on bunches of `iojs` and `node` versions. [`4c1fd65`](https://github.com/inspect-js/object-inspect/commit/4c1fd65cc3bd95307e854d114b90478324287fd2)
+- [Dev Deps] update `tape` [`88a907e`](https://github.com/inspect-js/object-inspect/commit/88a907e33afbe408e4b5d6e4e42a33143f88848c)
+
+## [1.0.2](https://github.com/inspect-js/object-inspect/compare/1.0.1...1.0.2) - 2015-08-07
+
+### Commits
+
+- [Fix] Cache `Object.prototype.hasOwnProperty` in case it's deleted later. [`1d0075d`](https://github.com/inspect-js/object-inspect/commit/1d0075d3091dc82246feeb1f9871cb2b8ed227b3)
+- [Dev Deps] Update `tape` [`ca8d5d7`](https://github.com/inspect-js/object-inspect/commit/ca8d5d75635ddbf76f944e628267581e04958457)
+- gitignore node_modules since this is a reusable modules. [`ed41407`](https://github.com/inspect-js/object-inspect/commit/ed41407811743ca530cdeb28f982beb96026af82)
+
+## [1.0.1](https://github.com/inspect-js/object-inspect/compare/1.0.0...1.0.1) - 2015-07-19
+
+### Commits
+
+- Make `inspect` work with symbol primitives and objects, including in node 0.11 and 0.12. [`ddf1b94`](https://github.com/inspect-js/object-inspect/commit/ddf1b94475ab951f1e3bccdc0a48e9073cfbfef4)
+- bump tape [`103d674`](https://github.com/inspect-js/object-inspect/commit/103d67496b504bdcfdd765d303a773f87ec106e2)
+- use newer travis config [`d497276`](https://github.com/inspect-js/object-inspect/commit/d497276c1da14234bb5098a59cf20de75fbc316a)
+
+## [1.0.0](https://github.com/inspect-js/object-inspect/compare/0.4.0...1.0.0) - 2014-08-05
+
+### Commits
+
+- error inspect works properly [`260a22d`](https://github.com/inspect-js/object-inspect/commit/260a22d134d3a8a482c67d52091c6040c34f4299)
+- seen coverage [`57269e8`](https://github.com/inspect-js/object-inspect/commit/57269e8baa992a7439047f47325111fdcbcb8417)
+- htmlelement instance coverage [`397ffe1`](https://github.com/inspect-js/object-inspect/commit/397ffe10a1980350868043ef9de65686d438979f)
+- more element coverage [`6905cc2`](https://github.com/inspect-js/object-inspect/commit/6905cc2f7df35600177e613b0642b4df5efd3eca)
+- failing test for type errors [`385b615`](https://github.com/inspect-js/object-inspect/commit/385b6152e49b51b68449a662f410b084ed7c601a)
+- fn name coverage [`edc906d`](https://github.com/inspect-js/object-inspect/commit/edc906d40fca6b9194d304062c037ee8e398c4c2)
+- server-side element test [`362d1d3`](https://github.com/inspect-js/object-inspect/commit/362d1d3e86f187651c29feeb8478110afada385b)
+- custom inspect fn [`e89b0f6`](https://github.com/inspect-js/object-inspect/commit/e89b0f6fe6d5e03681282af83732a509160435a6)
+- fixed browser test [`b530882`](https://github.com/inspect-js/object-inspect/commit/b5308824a1c8471c5617e394766a03a6977102a9)
+- depth test, matches node [`1cfd9e0`](https://github.com/inspect-js/object-inspect/commit/1cfd9e0285a4ae1dff44101ad482915d9bf47e48)
+- exercise hasOwnProperty path [`8d753fb`](https://github.com/inspect-js/object-inspect/commit/8d753fb362a534fa1106e4d80f2ee9bea06a66d9)
+- more cases covered for errors [`c5c46a5`](https://github.com/inspect-js/object-inspect/commit/c5c46a569ec4606583497e8550f0d8c7ad39a4a4)
+- \W obj key test case [`b0eceee`](https://github.com/inspect-js/object-inspect/commit/b0eceeea6e0eb94d686c1046e99b9e25e5005f75)
+- coverage for explicit depth param [`e12b91c`](https://github.com/inspect-js/object-inspect/commit/e12b91cd59683362f3a0e80f46481a0211e26c15)
+
+## [0.4.0](https://github.com/inspect-js/object-inspect/compare/0.3.1...0.4.0) - 2014-03-21
+
+### Commits
+
+- passing lowbyte interpolation test [`b847511`](https://github.com/inspect-js/object-inspect/commit/b8475114f5def7e7961c5353d48d3d8d9a520985)
+- lowbyte test [`4a2b0e1`](https://github.com/inspect-js/object-inspect/commit/4a2b0e142667fc933f195472759385ac08f3946c)
+
+## [0.3.1](https://github.com/inspect-js/object-inspect/compare/0.3.0...0.3.1) - 2014-03-04
+
+### Commits
+
+- sort keys [`a07b19c`](https://github.com/inspect-js/object-inspect/commit/a07b19cc3b1521a82d4fafb6368b7a9775428a05)
+
+## [0.3.0](https://github.com/inspect-js/object-inspect/compare/0.2.0...0.3.0) - 2014-03-04
+
+### Commits
+
+- [] and {} instead of [ ] and { } [`654c44b`](https://github.com/inspect-js/object-inspect/commit/654c44b2865811f3519e57bb8526e0821caf5c6b)
+
+## [0.2.0](https://github.com/inspect-js/object-inspect/compare/0.1.3...0.2.0) - 2014-03-04
+
+### Commits
+
+- failing holes test [`99cdfad`](https://github.com/inspect-js/object-inspect/commit/99cdfad03c6474740275a75636fe6ca86c77737a)
+- regex already work [`e324033`](https://github.com/inspect-js/object-inspect/commit/e324033267025995ec97d32ed0a65737c99477a6)
+- failing undef/null test [`1f88a00`](https://github.com/inspect-js/object-inspect/commit/1f88a00265d3209719dda8117b7e6360b4c20943)
+- holes in the all example [`7d345f3`](https://github.com/inspect-js/object-inspect/commit/7d345f3676dcbe980cff89a4f6c243269ebbb709)
+- check for .inspect(), fixes Buffer use-case [`c3f7546`](https://github.com/inspect-js/object-inspect/commit/c3f75466dbca125347d49847c05262c292f12b79)
+- fixes for holes [`ce25f73`](https://github.com/inspect-js/object-inspect/commit/ce25f736683de4b92ff27dc5471218415e2d78d8)
+- weird null behavior [`405c1ea`](https://github.com/inspect-js/object-inspect/commit/405c1ea72cd5a8cf3b498c3eaa903d01b9fbcab5)
+- tape is actually a devDependency, upgrade [`703b0ce`](https://github.com/inspect-js/object-inspect/commit/703b0ce6c5817b4245a082564bccd877e0bb6990)
+- put date in the example [`a342219`](https://github.com/inspect-js/object-inspect/commit/a3422190eeaa013215f46df2d0d37b48595ac058)
+- passing the null test [`4ab737e`](https://github.com/inspect-js/object-inspect/commit/4ab737ebf862a75d247ebe51e79307a34d6380d4)
+
+## [0.1.3](https://github.com/inspect-js/object-inspect/compare/0.1.1...0.1.3) - 2013-07-26
+
+### Commits
+
+- special isElement() check [`882768a`](https://github.com/inspect-js/object-inspect/commit/882768a54035d30747be9de1baf14e5aa0daa128)
+- oh right old IEs don't have indexOf either [`36d1275`](https://github.com/inspect-js/object-inspect/commit/36d12756c38b08a74370b0bb696c809e529913a5)
+
+## [0.1.1](https://github.com/inspect-js/object-inspect/compare/0.1.0...0.1.1) - 2013-07-26
+
+### Commits
+
+- tests! [`4422fd9`](https://github.com/inspect-js/object-inspect/commit/4422fd95532c2745aa6c4f786f35f1090be29998)
+- fix for ie<9, doesn't have hasOwnProperty [`6b7d611`](https://github.com/inspect-js/object-inspect/commit/6b7d61183050f6da801ea04473211da226482613)
+- fix for all IEs: no f.name [`4e0c2f6`](https://github.com/inspect-js/object-inspect/commit/4e0c2f6dfd01c306d067d7163319acc97c94ee50)
+- badges [`5ed0d88`](https://github.com/inspect-js/object-inspect/commit/5ed0d88e4e407f9cb327fa4a146c17921f9680f3)
+
+## [0.1.0](https://github.com/inspect-js/object-inspect/compare/0.0.0...0.1.0) - 2013-07-26
+
+### Commits
+
+- [Function] for functions [`ad5c485`](https://github.com/inspect-js/object-inspect/commit/ad5c485098fc83352cb540a60b2548ca56820e0b)
+
+## 0.0.0 - 2013-07-26
+
+### Commits
+
+- working browser example [`34be6b6`](https://github.com/inspect-js/object-inspect/commit/34be6b6548f9ce92bdc3c27572857ba0c4a1218d)
+- package.json etc [`cad51f2`](https://github.com/inspect-js/object-inspect/commit/cad51f23fc6bcf1a456ed6abe16088256c2f632f)
+- docs complete [`b80cce2`](https://github.com/inspect-js/object-inspect/commit/b80cce2490c4e7183a9ee11ea89071f0abec4446)
+- circular example [`4b4a7b9`](https://github.com/inspect-js/object-inspect/commit/4b4a7b92209e4e6b4630976cb6bcd17d14165a59)
+- string rep [`7afb479`](https://github.com/inspect-js/object-inspect/commit/7afb479baa798d27f09e0a178b72ea327f60f5c8)
diff --git a/server/node_modules/object-inspect/LICENSE b/server/node_modules/object-inspect/LICENSE
new file mode 100644
index 0000000..ca64cc1
--- /dev/null
+++ b/server/node_modules/object-inspect/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2013 James Halliday
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/object-inspect/example/all.js b/server/node_modules/object-inspect/example/all.js
new file mode 100644
index 0000000..2f3355c
--- /dev/null
+++ b/server/node_modules/object-inspect/example/all.js
@@ -0,0 +1,23 @@
+'use strict';
+
+var inspect = require('../');
+var Buffer = require('safer-buffer').Buffer;
+
+var holes = ['a', 'b'];
+holes[4] = 'e';
+holes[6] = 'g';
+
+var obj = {
+    a: 1,
+    b: [3, 4, undefined, null],
+    c: undefined,
+    d: null,
+    e: {
+        regex: /^x/i,
+        buf: Buffer.from('abc'),
+        holes: holes
+    },
+    now: new Date()
+};
+obj.self = obj;
+console.log(inspect(obj));
diff --git a/server/node_modules/object-inspect/example/circular.js b/server/node_modules/object-inspect/example/circular.js
new file mode 100644
index 0000000..487a7c1
--- /dev/null
+++ b/server/node_modules/object-inspect/example/circular.js
@@ -0,0 +1,6 @@
+'use strict';
+
+var inspect = require('../');
+var obj = { a: 1, b: [3, 4] };
+obj.c = obj;
+console.log(inspect(obj));
diff --git a/server/node_modules/object-inspect/example/fn.js b/server/node_modules/object-inspect/example/fn.js
new file mode 100644
index 0000000..9b5db8d
--- /dev/null
+++ b/server/node_modules/object-inspect/example/fn.js
@@ -0,0 +1,5 @@
+'use strict';
+
+var inspect = require('../');
+var obj = [1, 2, function f(n) { return n + 5; }, 4];
+console.log(inspect(obj));
diff --git a/server/node_modules/object-inspect/example/inspect.js b/server/node_modules/object-inspect/example/inspect.js
new file mode 100644
index 0000000..e2df7c9
--- /dev/null
+++ b/server/node_modules/object-inspect/example/inspect.js
@@ -0,0 +1,10 @@
+'use strict';
+
+/* eslint-env browser */
+var inspect = require('../');
+
+var d = document.createElement('div');
+d.setAttribute('id', 'beep');
+d.innerHTML = '<b>wooo</b><i>iiiii</i>';
+
+console.log(inspect([d, { a: 3, b: 4, c: [5, 6, [7, [8, [9]]]] }]));
diff --git a/server/node_modules/object-inspect/index.js b/server/node_modules/object-inspect/index.js
new file mode 100644
index 0000000..a4b2d4c
--- /dev/null
+++ b/server/node_modules/object-inspect/index.js
@@ -0,0 +1,544 @@
+var hasMap = typeof Map === 'function' && Map.prototype;
+var mapSizeDescriptor = Object.getOwnPropertyDescriptor && hasMap ? Object.getOwnPropertyDescriptor(Map.prototype, 'size') : null;
+var mapSize = hasMap && mapSizeDescriptor && typeof mapSizeDescriptor.get === 'function' ? mapSizeDescriptor.get : null;
+var mapForEach = hasMap && Map.prototype.forEach;
+var hasSet = typeof Set === 'function' && Set.prototype;
+var setSizeDescriptor = Object.getOwnPropertyDescriptor && hasSet ? Object.getOwnPropertyDescriptor(Set.prototype, 'size') : null;
+var setSize = hasSet && setSizeDescriptor && typeof setSizeDescriptor.get === 'function' ? setSizeDescriptor.get : null;
+var setForEach = hasSet && Set.prototype.forEach;
+var hasWeakMap = typeof WeakMap === 'function' && WeakMap.prototype;
+var weakMapHas = hasWeakMap ? WeakMap.prototype.has : null;
+var hasWeakSet = typeof WeakSet === 'function' && WeakSet.prototype;
+var weakSetHas = hasWeakSet ? WeakSet.prototype.has : null;
+var hasWeakRef = typeof WeakRef === 'function' && WeakRef.prototype;
+var weakRefDeref = hasWeakRef ? WeakRef.prototype.deref : null;
+var booleanValueOf = Boolean.prototype.valueOf;
+var objectToString = Object.prototype.toString;
+var functionToString = Function.prototype.toString;
+var $match = String.prototype.match;
+var $slice = String.prototype.slice;
+var $replace = String.prototype.replace;
+var $toUpperCase = String.prototype.toUpperCase;
+var $toLowerCase = String.prototype.toLowerCase;
+var $test = RegExp.prototype.test;
+var $concat = Array.prototype.concat;
+var $join = Array.prototype.join;
+var $arrSlice = Array.prototype.slice;
+var $floor = Math.floor;
+var bigIntValueOf = typeof BigInt === 'function' ? BigInt.prototype.valueOf : null;
+var gOPS = Object.getOwnPropertySymbols;
+var symToString = typeof Symbol === 'function' && typeof Symbol.iterator === 'symbol' ? Symbol.prototype.toString : null;
+var hasShammedSymbols = typeof Symbol === 'function' && typeof Symbol.iterator === 'object';
+// ie, `has-tostringtag/shams
+var toStringTag = typeof Symbol === 'function' && Symbol.toStringTag && (typeof Symbol.toStringTag === hasShammedSymbols ? 'object' : 'symbol')
+    ? Symbol.toStringTag
+    : null;
+var isEnumerable = Object.prototype.propertyIsEnumerable;
+
+var gPO = (typeof Reflect === 'function' ? Reflect.getPrototypeOf : Object.getPrototypeOf) || (
+    [].__proto__ === Array.prototype // eslint-disable-line no-proto
+        ? function (O) {
+            return O.__proto__; // eslint-disable-line no-proto
+        }
+        : null
+);
+
+function addNumericSeparator(num, str) {
+    if (
+        num === Infinity
+        || num === -Infinity
+        || num !== num
+        || (num && num > -1000 && num < 1000)
+        || $test.call(/e/, str)
+    ) {
+        return str;
+    }
+    var sepRegex = /[0-9](?=(?:[0-9]{3})+(?![0-9]))/g;
+    if (typeof num === 'number') {
+        var int = num < 0 ? -$floor(-num) : $floor(num); // trunc(num)
+        if (int !== num) {
+            var intStr = String(int);
+            var dec = $slice.call(str, intStr.length + 1);
+            return $replace.call(intStr, sepRegex, '$&_') + '.' + $replace.call($replace.call(dec, /([0-9]{3})/g, '$&_'), /_$/, '');
+        }
+    }
+    return $replace.call(str, sepRegex, '$&_');
+}
+
+var utilInspect = require('./util.inspect');
+var inspectCustom = utilInspect.custom;
+var inspectSymbol = isSymbol(inspectCustom) ? inspectCustom : null;
+
+var quotes = {
+    __proto__: null,
+    'double': '"',
+    single: "'"
+};
+var quoteREs = {
+    __proto__: null,
+    'double': /(["\\])/g,
+    single: /(['\\])/g
+};
+
+module.exports = function inspect_(obj, options, depth, seen) {
+    var opts = options || {};
+
+    if (has(opts, 'quoteStyle') && !has(quotes, opts.quoteStyle)) {
+        throw new TypeError('option "quoteStyle" must be "single" or "double"');
+    }
+    if (
+        has(opts, 'maxStringLength') && (typeof opts.maxStringLength === 'number'
+            ? opts.maxStringLength < 0 && opts.maxStringLength !== Infinity
+            : opts.maxStringLength !== null
+        )
+    ) {
+        throw new TypeError('option "maxStringLength", if provided, must be a positive integer, Infinity, or `null`');
+    }
+    var customInspect = has(opts, 'customInspect') ? opts.customInspect : true;
+    if (typeof customInspect !== 'boolean' && customInspect !== 'symbol') {
+        throw new TypeError('option "customInspect", if provided, must be `true`, `false`, or `\'symbol\'`');
+    }
+
+    if (
+        has(opts, 'indent')
+        && opts.indent !== null
+        && opts.indent !== '\t'
+        && !(parseInt(opts.indent, 10) === opts.indent && opts.indent > 0)
+    ) {
+        throw new TypeError('option "indent" must be "\\t", an integer > 0, or `null`');
+    }
+    if (has(opts, 'numericSeparator') && typeof opts.numericSeparator !== 'boolean') {
+        throw new TypeError('option "numericSeparator", if provided, must be `true` or `false`');
+    }
+    var numericSeparator = opts.numericSeparator;
+
+    if (typeof obj === 'undefined') {
+        return 'undefined';
+    }
+    if (obj === null) {
+        return 'null';
+    }
+    if (typeof obj === 'boolean') {
+        return obj ? 'true' : 'false';
+    }
+
+    if (typeof obj === 'string') {
+        return inspectString(obj, opts);
+    }
+    if (typeof obj === 'number') {
+        if (obj === 0) {
+            return Infinity / obj > 0 ? '0' : '-0';
+        }
+        var str = String(obj);
+        return numericSeparator ? addNumericSeparator(obj, str) : str;
+    }
+    if (typeof obj === 'bigint') {
+        var bigIntStr = String(obj) + 'n';
+        return numericSeparator ? addNumericSeparator(obj, bigIntStr) : bigIntStr;
+    }
+
+    var maxDepth = typeof opts.depth === 'undefined' ? 5 : opts.depth;
+    if (typeof depth === 'undefined') { depth = 0; }
+    if (depth >= maxDepth && maxDepth > 0 && typeof obj === 'object') {
+        return isArray(obj) ? '[Array]' : '[Object]';
+    }
+
+    var indent = getIndent(opts, depth);
+
+    if (typeof seen === 'undefined') {
+        seen = [];
+    } else if (indexOf(seen, obj) >= 0) {
+        return '[Circular]';
+    }
+
+    function inspect(value, from, noIndent) {
+        if (from) {
+            seen = $arrSlice.call(seen);
+            seen.push(from);
+        }
+        if (noIndent) {
+            var newOpts = {
+                depth: opts.depth
+            };
+            if (has(opts, 'quoteStyle')) {
+                newOpts.quoteStyle = opts.quoteStyle;
+            }
+            return inspect_(value, newOpts, depth + 1, seen);
+        }
+        return inspect_(value, opts, depth + 1, seen);
+    }
+
+    if (typeof obj === 'function' && !isRegExp(obj)) { // in older engines, regexes are callable
+        var name = nameOf(obj);
+        var keys = arrObjKeys(obj, inspect);
+        return '[Function' + (name ? ': ' + name : ' (anonymous)') + ']' + (keys.length > 0 ? ' { ' + $join.call(keys, ', ') + ' }' : '');
+    }
+    if (isSymbol(obj)) {
+        var symString = hasShammedSymbols ? $replace.call(String(obj), /^(Symbol$.*$)_[^)]*$/, '$1') : symToString.call(obj);
+        return typeof obj === 'object' && !hasShammedSymbols ? markBoxed(symString) : symString;
+    }
+    if (isElement(obj)) {
+        var s = '<' + $toLowerCase.call(String(obj.nodeName));
+        var attrs = obj.attributes || [];
+        for (var i = 0; i < attrs.length; i++) {
+            s += ' ' + attrs[i].name + '=' + wrapQuotes(quote(attrs[i].value), 'double', opts);
+        }
+        s += '>';
+        if (obj.childNodes && obj.childNodes.length) { s += '...'; }
+        s += '</' + $toLowerCase.call(String(obj.nodeName)) + '>';
+        return s;
+    }
+    if (isArray(obj)) {
+        if (obj.length === 0) { return '[]'; }
+        var xs = arrObjKeys(obj, inspect);
+        if (indent && !singleLineValues(xs)) {
+            return '[' + indentedJoin(xs, indent) + ']';
+        }
+        return '[ ' + $join.call(xs, ', ') + ' ]';
+    }
+    if (isError(obj)) {
+        var parts = arrObjKeys(obj, inspect);
+        if (!('cause' in Error.prototype) && 'cause' in obj && !isEnumerable.call(obj, 'cause')) {
+            return '{ [' + String(obj) + '] ' + $join.call($concat.call('[cause]: ' + inspect(obj.cause), parts), ', ') + ' }';
+        }
+        if (parts.length === 0) { return '[' + String(obj) + ']'; }
+        return '{ [' + String(obj) + '] ' + $join.call(parts, ', ') + ' }';
+    }
+    if (typeof obj === 'object' && customInspect) {
+        if (inspectSymbol && typeof obj[inspectSymbol] === 'function' && utilInspect) {
+            return utilInspect(obj, { depth: maxDepth - depth });
+        } else if (customInspect !== 'symbol' && typeof obj.inspect === 'function') {
+            return obj.inspect();
+        }
+    }
+    if (isMap(obj)) {
+        var mapParts = [];
+        if (mapForEach) {
+            mapForEach.call(obj, function (value, key) {
+                mapParts.push(inspect(key, obj, true) + ' => ' + inspect(value, obj));
+            });
+        }
+        return collectionOf('Map', mapSize.call(obj), mapParts, indent);
+    }
+    if (isSet(obj)) {
+        var setParts = [];
+        if (setForEach) {
+            setForEach.call(obj, function (value) {
+                setParts.push(inspect(value, obj));
+            });
+        }
+        return collectionOf('Set', setSize.call(obj), setParts, indent);
+    }
+    if (isWeakMap(obj)) {
+        return weakCollectionOf('WeakMap');
+    }
+    if (isWeakSet(obj)) {
+        return weakCollectionOf('WeakSet');
+    }
+    if (isWeakRef(obj)) {
+        return weakCollectionOf('WeakRef');
+    }
+    if (isNumber(obj)) {
+        return markBoxed(inspect(Number(obj)));
+    }
+    if (isBigInt(obj)) {
+        return markBoxed(inspect(bigIntValueOf.call(obj)));
+    }
+    if (isBoolean(obj)) {
+        return markBoxed(booleanValueOf.call(obj));
+    }
+    if (isString(obj)) {
+        return markBoxed(inspect(String(obj)));
+    }
+    // note: in IE 8, sometimes `global !== window` but both are the prototypes of each other
+    /* eslint-env browser */
+    if (typeof window !== 'undefined' && obj === window) {
+        return '{ [object Window] }';
+    }
+    if (
+        (typeof globalThis !== 'undefined' && obj === globalThis)
+        || (typeof global !== 'undefined' && obj === global)
+    ) {
+        return '{ [object globalThis] }';
+    }
+    if (!isDate(obj) && !isRegExp(obj)) {
+        var ys = arrObjKeys(obj, inspect);
+        var isPlainObject = gPO ? gPO(obj) === Object.prototype : obj instanceof Object || obj.constructor === Object;
+        var protoTag = obj instanceof Object ? '' : 'null prototype';
+        var stringTag = !isPlainObject && toStringTag && Object(obj) === obj && toStringTag in obj ? $slice.call(toStr(obj), 8, -1) : protoTag ? 'Object' : '';
+        var constructorTag = isPlainObject || typeof obj.constructor !== 'function' ? '' : obj.constructor.name ? obj.constructor.name + ' ' : '';
+        var tag = constructorTag + (stringTag || protoTag ? '[' + $join.call($concat.call([], stringTag || [], protoTag || []), ': ') + '] ' : '');
+        if (ys.length === 0) { return tag + '{}'; }
+        if (indent) {
+            return tag + '{' + indentedJoin(ys, indent) + '}';
+        }
+        return tag + '{ ' + $join.call(ys, ', ') + ' }';
+    }
+    return String(obj);
+};
+
+function wrapQuotes(s, defaultStyle, opts) {
+    var style = opts.quoteStyle || defaultStyle;
+    var quoteChar = quotes[style];
+    return quoteChar + s + quoteChar;
+}
+
+function quote(s) {
+    return $replace.call(String(s), /"/g, '"');
+}
+
+function canTrustToString(obj) {
+    return !toStringTag || !(typeof obj === 'object' && (toStringTag in obj || typeof obj[toStringTag] !== 'undefined'));
+}
+function isArray(obj) { return toStr(obj) === '[object Array]' && canTrustToString(obj); }
+function isDate(obj) { return toStr(obj) === '[object Date]' && canTrustToString(obj); }
+function isRegExp(obj) { return toStr(obj) === '[object RegExp]' && canTrustToString(obj); }
+function isError(obj) { return toStr(obj) === '[object Error]' && canTrustToString(obj); }
+function isString(obj) { return toStr(obj) === '[object String]' && canTrustToString(obj); }
+function isNumber(obj) { return toStr(obj) === '[object Number]' && canTrustToString(obj); }
+function isBoolean(obj) { return toStr(obj) === '[object Boolean]' && canTrustToString(obj); }
+
+// Symbol and BigInt do have Symbol.toStringTag by spec, so that can't be used to eliminate false positives
+function isSymbol(obj) {
+    if (hasShammedSymbols) {
+        return obj && typeof obj === 'object' && obj instanceof Symbol;
+    }
+    if (typeof obj === 'symbol') {
+        return true;
+    }
+    if (!obj || typeof obj !== 'object' || !symToString) {
+        return false;
+    }
+    try {
+        symToString.call(obj);
+        return true;
+    } catch (e) {}
+    return false;
+}
+
+function isBigInt(obj) {
+    if (!obj || typeof obj !== 'object' || !bigIntValueOf) {
+        return false;
+    }
+    try {
+        bigIntValueOf.call(obj);
+        return true;
+    } catch (e) {}
+    return false;
+}
+
+var hasOwn = Object.prototype.hasOwnProperty || function (key) { return key in this; };
+function has(obj, key) {
+    return hasOwn.call(obj, key);
+}
+
+function toStr(obj) {
+    return objectToString.call(obj);
+}
+
+function nameOf(f) {
+    if (f.name) { return f.name; }
+    var m = $match.call(functionToString.call(f), /^function\s*([\w$]+)/);
+    if (m) { return m[1]; }
+    return null;
+}
+
+function indexOf(xs, x) {
+    if (xs.indexOf) { return xs.indexOf(x); }
+    for (var i = 0, l = xs.length; i < l; i++) {
+        if (xs[i] === x) { return i; }
+    }
+    return -1;
+}
+
+function isMap(x) {
+    if (!mapSize || !x || typeof x !== 'object') {
+        return false;
+    }
+    try {
+        mapSize.call(x);
+        try {
+            setSize.call(x);
+        } catch (s) {
+            return true;
+        }
+        return x instanceof Map; // core-js workaround, pre-v2.5.0
+    } catch (e) {}
+    return false;
+}
+
+function isWeakMap(x) {
+    if (!weakMapHas || !x || typeof x !== 'object') {
+        return false;
+    }
+    try {
+        weakMapHas.call(x, weakMapHas);
+        try {
+            weakSetHas.call(x, weakSetHas);
+        } catch (s) {
+            return true;
+        }
+        return x instanceof WeakMap; // core-js workaround, pre-v2.5.0
+    } catch (e) {}
+    return false;
+}
+
+function isWeakRef(x) {
+    if (!weakRefDeref || !x || typeof x !== 'object') {
+        return false;
+    }
+    try {
+        weakRefDeref.call(x);
+        return true;
+    } catch (e) {}
+    return false;
+}
+
+function isSet(x) {
+    if (!setSize || !x || typeof x !== 'object') {
+        return false;
+    }
+    try {
+        setSize.call(x);
+        try {
+            mapSize.call(x);
+        } catch (m) {
+            return true;
+        }
+        return x instanceof Set; // core-js workaround, pre-v2.5.0
+    } catch (e) {}
+    return false;
+}
+
+function isWeakSet(x) {
+    if (!weakSetHas || !x || typeof x !== 'object') {
+        return false;
+    }
+    try {
+        weakSetHas.call(x, weakSetHas);
+        try {
+            weakMapHas.call(x, weakMapHas);
+        } catch (s) {
+            return true;
+        }
+        return x instanceof WeakSet; // core-js workaround, pre-v2.5.0
+    } catch (e) {}
+    return false;
+}
+
+function isElement(x) {
+    if (!x || typeof x !== 'object') { return false; }
+    if (typeof HTMLElement !== 'undefined' && x instanceof HTMLElement) {
+        return true;
+    }
+    return typeof x.nodeName === 'string' && typeof x.getAttribute === 'function';
+}
+
+function inspectString(str, opts) {
+    if (str.length > opts.maxStringLength) {
+        var remaining = str.length - opts.maxStringLength;
+        var trailer = '... ' + remaining + ' more character' + (remaining > 1 ? 's' : '');
+        return inspectString($slice.call(str, 0, opts.maxStringLength), opts) + trailer;
+    }
+    var quoteRE = quoteREs[opts.quoteStyle || 'single'];
+    quoteRE.lastIndex = 0;
+    // eslint-disable-next-line no-control-regex
+    var s = $replace.call($replace.call(str, quoteRE, '\\$1'), /[\x00-\x1f]/g, lowbyte);
+    return wrapQuotes(s, 'single', opts);
+}
+
+function lowbyte(c) {
+    var n = c.charCodeAt(0);
+    var x = {
+        8: 'b',
+        9: 't',
+        10: 'n',
+        12: 'f',
+        13: 'r'
+    }[n];
+    if (x) { return '\\' + x; }
+    return '\\x' + (n < 0x10 ? '0' : '') + $toUpperCase.call(n.toString(16));
+}
+
+function markBoxed(str) {
+    return 'Object(' + str + ')';
+}
+
+function weakCollectionOf(type) {
+    return type + ' { ? }';
+}
+
+function collectionOf(type, size, entries, indent) {
+    var joinedEntries = indent ? indentedJoin(entries, indent) : $join.call(entries, ', ');
+    return type + ' (' + size + ') {' + joinedEntries + '}';
+}
+
+function singleLineValues(xs) {
+    for (var i = 0; i < xs.length; i++) {
+        if (indexOf(xs[i], '\n') >= 0) {
+            return false;
+        }
+    }
+    return true;
+}
+
+function getIndent(opts, depth) {
+    var baseIndent;
+    if (opts.indent === '\t') {
+        baseIndent = '\t';
+    } else if (typeof opts.indent === 'number' && opts.indent > 0) {
+        baseIndent = $join.call(Array(opts.indent + 1), ' ');
+    } else {
+        return null;
+    }
+    return {
+        base: baseIndent,
+        prev: $join.call(Array(depth + 1), baseIndent)
+    };
+}
+
+function indentedJoin(xs, indent) {
+    if (xs.length === 0) { return ''; }
+    var lineJoiner = '\n' + indent.prev + indent.base;
+    return lineJoiner + $join.call(xs, ',' + lineJoiner) + '\n' + indent.prev;
+}
+
+function arrObjKeys(obj, inspect) {
+    var isArr = isArray(obj);
+    var xs = [];
+    if (isArr) {
+        xs.length = obj.length;
+        for (var i = 0; i < obj.length; i++) {
+            xs[i] = has(obj, i) ? inspect(obj[i], obj) : '';
+        }
+    }
+    var syms = typeof gOPS === 'function' ? gOPS(obj) : [];
+    var symMap;
+    if (hasShammedSymbols) {
+        symMap = {};
+        for (var k = 0; k < syms.length; k++) {
+            symMap['$' + syms[k]] = syms[k];
+        }
+    }
+
+    for (var key in obj) { // eslint-disable-line no-restricted-syntax
+        if (!has(obj, key)) { continue; } // eslint-disable-line no-restricted-syntax, no-continue
+        if (isArr && String(Number(key)) === key && key < obj.length) { continue; } // eslint-disable-line no-restricted-syntax, no-continue
+        if (hasShammedSymbols && symMap['$' + key] instanceof Symbol) {
+            // this is to prevent shammed Symbols, which are stored as strings, from being included in the string key section
+            continue; // eslint-disable-line no-restricted-syntax, no-continue
+        } else if ($test.call(/[^\w$]/, key)) {
+            xs.push(inspect(key, obj) + ': ' + inspect(obj[key], obj));
+        } else {
+            xs.push(key + ': ' + inspect(obj[key], obj));
+        }
+    }
+    if (typeof gOPS === 'function') {
+        for (var j = 0; j < syms.length; j++) {
+            if (isEnumerable.call(obj, syms[j])) {
+                xs.push('[' + inspect(syms[j]) + ']: ' + inspect(obj[syms[j]], obj));
+            }
+        }
+    }
+    return xs;
+}
diff --git a/server/node_modules/object-inspect/package-support.json b/server/node_modules/object-inspect/package-support.json
new file mode 100644
index 0000000..5cc12d0
--- /dev/null
+++ b/server/node_modules/object-inspect/package-support.json
@@ -0,0 +1,20 @@
+{
+  "versions": [
+    {
+      "version": "*",
+      "target": {
+        "node": "all"
+      },
+      "response": {
+        "type": "time-permitting"
+      },
+      "backing": {
+        "npm-funding": true,
+        "donations": [
+          "https://github.com/ljharb",
+          "https://tidelift.com/funding/github/npm/object-inspect"
+        ]
+      }
+    }
+  ]
+}
diff --git a/server/node_modules/object-inspect/package.json b/server/node_modules/object-inspect/package.json
new file mode 100644
index 0000000..9fd97ff
--- /dev/null
+++ b/server/node_modules/object-inspect/package.json
@@ -0,0 +1,105 @@
+{
+  "name": "object-inspect",
+  "version": "1.13.4",
+  "description": "string representations of objects in node and the browser",
+  "main": "index.js",
+  "sideEffects": false,
+  "devDependencies": {
+    "@ljharb/eslint-config": "^21.1.1",
+    "@pkgjs/support": "^0.0.6",
+    "auto-changelog": "^2.5.0",
+    "core-js": "^2.6.12",
+    "error-cause": "^1.0.8",
+    "es-value-fixtures": "^1.7.1",
+    "eslint": "=8.8.0",
+    "for-each": "^0.3.4",
+    "functions-have-names": "^1.2.3",
+    "glob": "=10.3.7",
+    "globalthis": "^1.0.4",
+    "has-symbols": "^1.1.0",
+    "has-tostringtag": "^1.0.2",
+    "in-publish": "^2.0.1",
+    "jackspeak": "=2.1.1",
+    "make-arrow-function": "^1.2.0",
+    "mock-property": "^1.1.0",
+    "npmignore": "^0.3.1",
+    "nyc": "^10.3.2",
+    "safe-publish-latest": "^2.0.0",
+    "safer-buffer": "^2.1.2",
+    "semver": "^6.3.1",
+    "string.prototype.repeat": "^1.0.0",
+    "tape": "^5.9.0"
+  },
+  "scripts": {
+    "prepack": "npmignore --auto --commentLines=autogenerated",
+    "prepublish": "not-in-publish || npm run prepublishOnly",
+    "prepublishOnly": "safe-publish-latest",
+    "pretest": "npm run lint",
+    "lint": "eslint --ext=js,mjs .",
+    "postlint": "npx @pkgjs/support validate",
+    "test": "npm run tests-only && npm run test:corejs",
+    "tests-only": "nyc tape 'test/*.js'",
+    "test:corejs": "nyc tape test-core-js.js 'test/*.js'",
+    "posttest": "npx npm@'>=10.2' audit --production",
+    "version": "auto-changelog && git add CHANGELOG.md",
+    "postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+  },
+  "testling": {
+    "files": [
+      "test/*.js",
+      "test/browser/*.js"
+    ],
+    "browsers": [
+      "ie/6..latest",
+      "chrome/latest",
+      "firefox/latest",
+      "safari/latest",
+      "opera/latest",
+      "iphone/latest",
+      "ipad/latest",
+      "android/latest"
+    ]
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/inspect-js/object-inspect.git"
+  },
+  "homepage": "https://github.com/inspect-js/object-inspect",
+  "keywords": [
+    "inspect",
+    "util.inspect",
+    "object",
+    "stringify",
+    "pretty"
+  ],
+  "author": {
+    "name": "James Halliday",
+    "email": "mail@substack.net",
+    "url": "http://substack.net"
+  },
+  "funding": {
+    "url": "https://github.com/sponsors/ljharb"
+  },
+  "license": "MIT",
+  "browser": {
+    "./util.inspect.js": false
+  },
+  "auto-changelog": {
+    "output": "CHANGELOG.md",
+    "template": "keepachangelog",
+    "unreleased": false,
+    "commitLimit": false,
+    "backfillLimit": false,
+    "hideCredit": true
+  },
+  "publishConfig": {
+    "ignore": [
+      ".github/workflows",
+      "./test-core-js.js"
+    ]
+  },
+  "support": true,
+  "engines": {
+    "node": ">= 0.4"
+  }
+}
diff --git a/server/node_modules/object-inspect/readme.markdown b/server/node_modules/object-inspect/readme.markdown
new file mode 100644
index 0000000..f91617d
--- /dev/null
+++ b/server/node_modules/object-inspect/readme.markdown
@@ -0,0 +1,84 @@
+# object-inspect <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+string representations of objects in node and the browser
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+# example
+
+## circular
+
+``` js
+var inspect = require('object-inspect');
+var obj = { a: 1, b: [3,4] };
+obj.c = obj;
+console.log(inspect(obj));
+```
+
+## dom element
+
+``` js
+var inspect = require('object-inspect');
+
+var d = document.createElement('div');
+d.setAttribute('id', 'beep');
+d.innerHTML = '<b>wooo</b><i>iiiii</i>';
+
+console.log(inspect([ d, { a: 3, b : 4, c: [5,6,[7,[8,[9]]]] } ]));
+```
+
+output:
+
+```
+[ <div id="beep">...</div>, { a: 3, b: 4, c: [ 5, 6, [ 7, [ 8, [ ... ] ] ] ] } ]
+```
+
+# methods
+
+``` js
+var inspect = require('object-inspect')
+```
+
+## var s = inspect(obj, opts={})
+
+Return a string `s` with the string representation of `obj` up to a depth of `opts.depth`.
+
+Additional options:
+  - `quoteStyle`: must be "single" or "double", if present. Default `'single'` for strings, `'double'` for HTML elements.
+  - `maxStringLength`: must be `0`, a positive integer, `Infinity`, or `null`, if present. Default `Infinity`.
+  - `customInspect`: When `true`, a custom inspect method function will be invoked (either undere the `util.inspect.custom` symbol, or the `inspect` property). When the string `'symbol'`, only the symbol method will be invoked. Default `true`.
+  - `indent`: must be "\t", `null`, or a positive integer. Default `null`.
+  - `numericSeparator`: must be a boolean, if present. Default `false`. If `true`, all numbers will be printed with numeric separators (eg, `1234.5678` will be printed as `'1_234.567_8'`)
+
+# install
+
+With [npm](https://npmjs.org) do:
+
+```
+npm install object-inspect
+```
+
+# license
+
+MIT
+
+[package-url]: https://npmjs.org/package/object-inspect
+[npm-version-svg]: https://versionbadg.es/inspect-js/object-inspect.svg
+[deps-svg]: https://david-dm.org/inspect-js/object-inspect.svg
+[deps-url]: https://david-dm.org/inspect-js/object-inspect
+[dev-deps-svg]: https://david-dm.org/inspect-js/object-inspect/dev-status.svg
+[dev-deps-url]: https://david-dm.org/inspect-js/object-inspect#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/object-inspect.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/object-inspect.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/object-inspect.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=object-inspect
+[codecov-image]: https://codecov.io/gh/inspect-js/object-inspect/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/inspect-js/object-inspect/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/inspect-js/object-inspect
+[actions-url]: https://github.com/inspect-js/object-inspect/actions
diff --git a/server/node_modules/object-inspect/test-core-js.js b/server/node_modules/object-inspect/test-core-js.js
new file mode 100644
index 0000000..e53c400
--- /dev/null
+++ b/server/node_modules/object-inspect/test-core-js.js
@@ -0,0 +1,26 @@
+'use strict';
+
+require('core-js');
+
+var inspect = require('./');
+var test = require('tape');
+
+test('Maps', function (t) {
+    t.equal(inspect(new Map([[1, 2]])), 'Map (1) {1 => 2}');
+    t.end();
+});
+
+test('WeakMaps', function (t) {
+    t.equal(inspect(new WeakMap([[{}, 2]])), 'WeakMap { ? }');
+    t.end();
+});
+
+test('Sets', function (t) {
+    t.equal(inspect(new Set([[1, 2]])), 'Set (1) {[ 1, 2 ]}');
+    t.end();
+});
+
+test('WeakSets', function (t) {
+    t.equal(inspect(new WeakSet([[1, 2]])), 'WeakSet { ? }');
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/test/bigint.js b/server/node_modules/object-inspect/test/bigint.js
new file mode 100644
index 0000000..4ecc31d
--- /dev/null
+++ b/server/node_modules/object-inspect/test/bigint.js
@@ -0,0 +1,58 @@
+'use strict';
+
+var inspect = require('../');
+var test = require('tape');
+var hasToStringTag = require('has-tostringtag/shams')();
+
+test('bigint', { skip: typeof BigInt === 'undefined' }, function (t) {
+    t.test('primitives', function (st) {
+        st.plan(3);
+
+        st.equal(inspect(BigInt(-256)), '-256n');
+        st.equal(inspect(BigInt(0)), '0n');
+        st.equal(inspect(BigInt(256)), '256n');
+    });
+
+    t.test('objects', function (st) {
+        st.plan(3);
+
+        st.equal(inspect(Object(BigInt(-256))), 'Object(-256n)');
+        st.equal(inspect(Object(BigInt(0))), 'Object(0n)');
+        st.equal(inspect(Object(BigInt(256))), 'Object(256n)');
+    });
+
+    t.test('syntactic primitives', function (st) {
+        st.plan(3);
+
+        /* eslint-disable no-new-func */
+        st.equal(inspect(Function('return -256n')()), '-256n');
+        st.equal(inspect(Function('return 0n')()), '0n');
+        st.equal(inspect(Function('return 256n')()), '256n');
+    });
+
+    t.test('toStringTag', { skip: !hasToStringTag }, function (st) {
+        st.plan(1);
+
+        var faker = {};
+        faker[Symbol.toStringTag] = 'BigInt';
+        st.equal(
+            inspect(faker),
+            '{ [Symbol(Symbol.toStringTag)]: \'BigInt\' }',
+            'object lying about being a BigInt inspects as an object'
+        );
+    });
+
+    t.test('numericSeparator', function (st) {
+        st.equal(inspect(BigInt(0), { numericSeparator: false }), '0n', '0n, numericSeparator false');
+        st.equal(inspect(BigInt(0), { numericSeparator: true }), '0n', '0n, numericSeparator true');
+
+        st.equal(inspect(BigInt(1234), { numericSeparator: false }), '1234n', '1234n, numericSeparator false');
+        st.equal(inspect(BigInt(1234), { numericSeparator: true }), '1_234n', '1234n, numericSeparator true');
+        st.equal(inspect(BigInt(-1234), { numericSeparator: false }), '-1234n', '1234n, numericSeparator false');
+        st.equal(inspect(BigInt(-1234), { numericSeparator: true }), '-1_234n', '1234n, numericSeparator true');
+
+        st.end();
+    });
+
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/test/browser/dom.js b/server/node_modules/object-inspect/test/browser/dom.js
new file mode 100644
index 0000000..210c0b2
--- /dev/null
+++ b/server/node_modules/object-inspect/test/browser/dom.js
@@ -0,0 +1,15 @@
+var inspect = require('../../');
+var test = require('tape');
+
+test('dom element', function (t) {
+    t.plan(1);
+
+    var d = document.createElement('div');
+    d.setAttribute('id', 'beep');
+    d.innerHTML = '<b>wooo</b><i>iiiii</i>';
+
+    t.equal(
+        inspect([d, { a: 3, b: 4, c: [5, 6, [7, [8, [9]]]] }]),
+        '[ <div id="beep">...</div>, { a: 3, b: 4, c: [ 5, 6, [ 7, [ 8, [Object] ] ] ] } ]'
+    );
+});
diff --git a/server/node_modules/object-inspect/test/circular.js b/server/node_modules/object-inspect/test/circular.js
new file mode 100644
index 0000000..5df4233
--- /dev/null
+++ b/server/node_modules/object-inspect/test/circular.js
@@ -0,0 +1,16 @@
+var inspect = require('../');
+var test = require('tape');
+
+test('circular', function (t) {
+    t.plan(2);
+    var obj = { a: 1, b: [3, 4] };
+    obj.c = obj;
+    t.equal(inspect(obj), '{ a: 1, b: [ 3, 4 ], c: [Circular] }');
+
+    var double = {};
+    double.a = [double];
+    double.b = {};
+    double.b.inner = double.b;
+    double.b.obj = double;
+    t.equal(inspect(double), '{ a: [ [Circular] ], b: { inner: [Circular], obj: [Circular] } }');
+});
diff --git a/server/node_modules/object-inspect/test/deep.js b/server/node_modules/object-inspect/test/deep.js
new file mode 100644
index 0000000..99ce32a
--- /dev/null
+++ b/server/node_modules/object-inspect/test/deep.js
@@ -0,0 +1,12 @@
+var inspect = require('../');
+var test = require('tape');
+
+test('deep', function (t) {
+    t.plan(4);
+    var obj = [[[[[[500]]]]]];
+    t.equal(inspect(obj), '[ [ [ [ [ [Array] ] ] ] ] ]');
+    t.equal(inspect(obj, { depth: 4 }), '[ [ [ [ [Array] ] ] ] ]');
+    t.equal(inspect(obj, { depth: 2 }), '[ [ [Array] ] ]');
+
+    t.equal(inspect([[[{ a: 1 }]]], { depth: 3 }), '[ [ [ [Object] ] ] ]');
+});
diff --git a/server/node_modules/object-inspect/test/element.js b/server/node_modules/object-inspect/test/element.js
new file mode 100644
index 0000000..47fa9e2
--- /dev/null
+++ b/server/node_modules/object-inspect/test/element.js
@@ -0,0 +1,53 @@
+var inspect = require('../');
+var test = require('tape');
+
+test('element', function (t) {
+    t.plan(3);
+    var elem = {
+        nodeName: 'div',
+        attributes: [{ name: 'class', value: 'row' }],
+        getAttribute: function (key) { return key; },
+        childNodes: []
+    };
+    var obj = [1, elem, 3];
+    t.deepEqual(inspect(obj), '[ 1, <div class="row"></div>, 3 ]');
+    t.deepEqual(inspect(obj, { quoteStyle: 'single' }), "[ 1, <div class='row'></div>, 3 ]");
+    t.deepEqual(inspect(obj, { quoteStyle: 'double' }), '[ 1, <div class="row"></div>, 3 ]');
+});
+
+test('element no attr', function (t) {
+    t.plan(1);
+    var elem = {
+        nodeName: 'div',
+        getAttribute: function (key) { return key; },
+        childNodes: []
+    };
+    var obj = [1, elem, 3];
+    t.deepEqual(inspect(obj), '[ 1, <div></div>, 3 ]');
+});
+
+test('element with contents', function (t) {
+    t.plan(1);
+    var elem = {
+        nodeName: 'div',
+        getAttribute: function (key) { return key; },
+        childNodes: [{ nodeName: 'b' }]
+    };
+    var obj = [1, elem, 3];
+    t.deepEqual(inspect(obj), '[ 1, <div>...</div>, 3 ]');
+});
+
+test('element instance', function (t) {
+    t.plan(1);
+    var h = global.HTMLElement;
+    global.HTMLElement = function (name, attr) {
+        this.nodeName = name;
+        this.attributes = attr;
+    };
+    global.HTMLElement.prototype.getAttribute = function () {};
+
+    var elem = new global.HTMLElement('div', []);
+    var obj = [1, elem, 3];
+    t.deepEqual(inspect(obj), '[ 1, <div></div>, 3 ]');
+    global.HTMLElement = h;
+});
diff --git a/server/node_modules/object-inspect/test/err.js b/server/node_modules/object-inspect/test/err.js
new file mode 100644
index 0000000..cc1d884
--- /dev/null
+++ b/server/node_modules/object-inspect/test/err.js
@@ -0,0 +1,48 @@
+var test = require('tape');
+var ErrorWithCause = require('error-cause/Error');
+
+var inspect = require('../');
+
+test('type error', function (t) {
+    t.plan(1);
+    var aerr = new TypeError();
+    aerr.foo = 555;
+    aerr.bar = [1, 2, 3];
+
+    var berr = new TypeError('tuv');
+    berr.baz = 555;
+
+    var cerr = new SyntaxError();
+    cerr.message = 'whoa';
+    cerr['a-b'] = 5;
+
+    var withCause = new ErrorWithCause('foo', { cause: 'bar' });
+    var withCausePlus = new ErrorWithCause('foo', { cause: 'bar' });
+    withCausePlus.foo = 'bar';
+    var withUndefinedCause = new ErrorWithCause('foo', { cause: undefined });
+    var withEnumerableCause = new Error('foo');
+    withEnumerableCause.cause = 'bar';
+
+    var obj = [
+        new TypeError(),
+        new TypeError('xxx'),
+        aerr,
+        berr,
+        cerr,
+        withCause,
+        withCausePlus,
+        withUndefinedCause,
+        withEnumerableCause
+    ];
+    t.equal(inspect(obj), '[ ' + [
+        '[TypeError]',
+        '[TypeError: xxx]',
+        '{ [TypeError] foo: 555, bar: [ 1, 2, 3 ] }',
+        '{ [TypeError: tuv] baz: 555 }',
+        '{ [SyntaxError: whoa] message: \'whoa\', \'a-b\': 5 }',
+        'cause' in Error.prototype ? '[Error: foo]' : '{ [Error: foo] [cause]: \'bar\' }',
+        '{ [Error: foo] ' + ('cause' in Error.prototype ? '' : '[cause]: \'bar\', ') + 'foo: \'bar\' }',
+        'cause' in Error.prototype ? '[Error: foo]' : '{ [Error: foo] [cause]: undefined }',
+        '{ [Error: foo] cause: \'bar\' }'
+    ].join(', ') + ' ]');
+});
diff --git a/server/node_modules/object-inspect/test/fakes.js b/server/node_modules/object-inspect/test/fakes.js
new file mode 100644
index 0000000..a65c08c
--- /dev/null
+++ b/server/node_modules/object-inspect/test/fakes.js
@@ -0,0 +1,29 @@
+'use strict';
+
+var inspect = require('../');
+var test = require('tape');
+var hasToStringTag = require('has-tostringtag/shams')();
+var forEach = require('for-each');
+
+test('fakes', { skip: !hasToStringTag }, function (t) {
+    forEach([
+        'Array',
+        'Boolean',
+        'Date',
+        'Error',
+        'Number',
+        'RegExp',
+        'String'
+    ], function (expected) {
+        var faker = {};
+        faker[Symbol.toStringTag] = expected;
+
+        t.equal(
+            inspect(faker),
+            '{ [Symbol(Symbol.toStringTag)]: \'' + expected + '\' }',
+            'faker masquerading as ' + expected + ' is not shown as one'
+        );
+    });
+
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/test/fn.js b/server/node_modules/object-inspect/test/fn.js
new file mode 100644
index 0000000..de3ca62
--- /dev/null
+++ b/server/node_modules/object-inspect/test/fn.js
@@ -0,0 +1,76 @@
+var inspect = require('../');
+var test = require('tape');
+var arrow = require('make-arrow-function')();
+var functionsHaveConfigurableNames = require('functions-have-names').functionsHaveConfigurableNames();
+
+test('function', function (t) {
+    t.plan(1);
+    var obj = [1, 2, function f(n) { return n; }, 4];
+    t.equal(inspect(obj), '[ 1, 2, [Function: f], 4 ]');
+});
+
+test('function name', function (t) {
+    t.plan(1);
+    var f = (function () {
+        return function () {};
+    }());
+    f.toString = function toStr() { return 'function xxx () {}'; };
+    var obj = [1, 2, f, 4];
+    t.equal(inspect(obj), '[ 1, 2, [Function (anonymous)] { toString: [Function: toStr] }, 4 ]');
+});
+
+test('anon function', function (t) {
+    var f = (function () {
+        return function () {};
+    }());
+    var obj = [1, 2, f, 4];
+    t.equal(inspect(obj), '[ 1, 2, [Function (anonymous)], 4 ]');
+
+    t.end();
+});
+
+test('arrow function', { skip: !arrow }, function (t) {
+    t.equal(inspect(arrow), '[Function (anonymous)]');
+
+    t.end();
+});
+
+test('truly nameless function', { skip: !arrow || !functionsHaveConfigurableNames }, function (t) {
+    function f() {}
+    Object.defineProperty(f, 'name', { value: false });
+    t.equal(f.name, false);
+    t.equal(
+        inspect(f),
+        '[Function: f]',
+        'named function with falsy `.name` does not hide its original name'
+    );
+
+    function g() {}
+    Object.defineProperty(g, 'name', { value: true });
+    t.equal(g.name, true);
+    t.equal(
+        inspect(g),
+        '[Function: true]',
+        'named function with truthy `.name` hides its original name'
+    );
+
+    var anon = function () {}; // eslint-disable-line func-style
+    Object.defineProperty(anon, 'name', { value: null });
+    t.equal(anon.name, null);
+    t.equal(
+        inspect(anon),
+        '[Function (anonymous)]',
+        'anon function with falsy `.name` does not hide its anonymity'
+    );
+
+    var anon2 = function () {}; // eslint-disable-line func-style
+    Object.defineProperty(anon2, 'name', { value: 1 });
+    t.equal(anon2.name, 1);
+    t.equal(
+        inspect(anon2),
+        '[Function: 1]',
+        'anon function with truthy `.name` hides its anonymity'
+    );
+
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/test/global.js b/server/node_modules/object-inspect/test/global.js
new file mode 100644
index 0000000..c57216a
--- /dev/null
+++ b/server/node_modules/object-inspect/test/global.js
@@ -0,0 +1,17 @@
+'use strict';
+
+var inspect = require('../');
+
+var test = require('tape');
+var globalThis = require('globalthis')();
+
+test('global object', function (t) {
+    /* eslint-env browser */
+    var expected = typeof window === 'undefined' ? 'globalThis' : 'Window';
+    t.equal(
+        inspect([globalThis]),
+        '[ { [object ' + expected + '] } ]'
+    );
+
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/test/has.js b/server/node_modules/object-inspect/test/has.js
new file mode 100644
index 0000000..01800de
--- /dev/null
+++ b/server/node_modules/object-inspect/test/has.js
@@ -0,0 +1,15 @@
+'use strict';
+
+var inspect = require('../');
+var test = require('tape');
+var mockProperty = require('mock-property');
+
+test('when Object#hasOwnProperty is deleted', function (t) {
+    t.plan(1);
+    var arr = [1, , 3]; // eslint-disable-line no-sparse-arrays
+
+    t.teardown(mockProperty(Array.prototype, 1, { value: 2 })); // this is needed to account for "in" vs "hasOwnProperty"
+    t.teardown(mockProperty(Object.prototype, 'hasOwnProperty', { 'delete': true }));
+
+    t.equal(inspect(arr), '[ 1, , 3 ]');
+});
diff --git a/server/node_modules/object-inspect/test/holes.js b/server/node_modules/object-inspect/test/holes.js
new file mode 100644
index 0000000..87fc8c8
--- /dev/null
+++ b/server/node_modules/object-inspect/test/holes.js
@@ -0,0 +1,15 @@
+var test = require('tape');
+var inspect = require('../');
+
+var xs = ['a', 'b'];
+xs[5] = 'f';
+xs[7] = 'j';
+xs[8] = 'k';
+
+test('holes', function (t) {
+    t.plan(1);
+    t.equal(
+        inspect(xs),
+        "[ 'a', 'b', , , , 'f', , 'j', 'k' ]"
+    );
+});
diff --git a/server/node_modules/object-inspect/test/indent-option.js b/server/node_modules/object-inspect/test/indent-option.js
new file mode 100644
index 0000000..89d8fce
--- /dev/null
+++ b/server/node_modules/object-inspect/test/indent-option.js
@@ -0,0 +1,271 @@
+var test = require('tape');
+var forEach = require('for-each');
+
+var inspect = require('../');
+
+test('bad indent options', function (t) {
+    forEach([
+        undefined,
+        true,
+        false,
+        -1,
+        1.2,
+        Infinity,
+        -Infinity,
+        NaN
+    ], function (indent) {
+        t['throws'](
+            function () { inspect('', { indent: indent }); },
+            TypeError,
+            inspect(indent) + ' is invalid'
+        );
+    });
+
+    t.end();
+});
+
+test('simple object with indent', function (t) {
+    t.plan(2);
+
+    var obj = { a: 1, b: 2 };
+
+    var expectedSpaces = [
+        '{',
+        '  a: 1,',
+        '  b: 2',
+        '}'
+    ].join('\n');
+    var expectedTabs = [
+        '{',
+        '	a: 1,',
+        '	b: 2',
+        '}'
+    ].join('\n');
+
+    t.equal(inspect(obj, { indent: 2 }), expectedSpaces, 'two');
+    t.equal(inspect(obj, { indent: '\t' }), expectedTabs, 'tabs');
+});
+
+test('two deep object with indent', function (t) {
+    t.plan(2);
+
+    var obj = { a: 1, b: { c: 3, d: 4 } };
+
+    var expectedSpaces = [
+        '{',
+        '  a: 1,',
+        '  b: {',
+        '    c: 3,',
+        '    d: 4',
+        '  }',
+        '}'
+    ].join('\n');
+    var expectedTabs = [
+        '{',
+        '	a: 1,',
+        '	b: {',
+        '		c: 3,',
+        '		d: 4',
+        '	}',
+        '}'
+    ].join('\n');
+
+    t.equal(inspect(obj, { indent: 2 }), expectedSpaces, 'two');
+    t.equal(inspect(obj, { indent: '\t' }), expectedTabs, 'tabs');
+});
+
+test('simple array with all single line elements', function (t) {
+    t.plan(2);
+
+    var obj = [1, 2, 3, 'asdf\nsdf'];
+
+    var expected = '[ 1, 2, 3, \'asdf\\nsdf\' ]';
+
+    t.equal(inspect(obj, { indent: 2 }), expected, 'two');
+    t.equal(inspect(obj, { indent: '\t' }), expected, 'tabs');
+});
+
+test('array with complex elements', function (t) {
+    t.plan(2);
+
+    var obj = [1, { a: 1, b: { c: 1 } }, 'asdf\nsdf'];
+
+    var expectedSpaces = [
+        '[',
+        '  1,',
+        '  {',
+        '    a: 1,',
+        '    b: {',
+        '      c: 1',
+        '    }',
+        '  },',
+        '  \'asdf\\nsdf\'',
+        ']'
+    ].join('\n');
+    var expectedTabs = [
+        '[',
+        '	1,',
+        '	{',
+        '		a: 1,',
+        '		b: {',
+        '			c: 1',
+        '		}',
+        '	},',
+        '	\'asdf\\nsdf\'',
+        ']'
+    ].join('\n');
+
+    t.equal(inspect(obj, { indent: 2 }), expectedSpaces, 'two');
+    t.equal(inspect(obj, { indent: '\t' }), expectedTabs, 'tabs');
+});
+
+test('values', function (t) {
+    t.plan(2);
+    var obj = [{}, [], { 'a-b': 5 }];
+
+    var expectedSpaces = [
+        '[',
+        '  {},',
+        '  [],',
+        '  {',
+        '    \'a-b\': 5',
+        '  }',
+        ']'
+    ].join('\n');
+    var expectedTabs = [
+        '[',
+        '	{},',
+        '	[],',
+        '	{',
+        '		\'a-b\': 5',
+        '	}',
+        ']'
+    ].join('\n');
+
+    t.equal(inspect(obj, { indent: 2 }), expectedSpaces, 'two');
+    t.equal(inspect(obj, { indent: '\t' }), expectedTabs, 'tabs');
+});
+
+test('Map', { skip: typeof Map !== 'function' }, function (t) {
+    var map = new Map();
+    map.set({ a: 1 }, ['b']);
+    map.set(3, NaN);
+
+    var expectedStringSpaces = [
+        'Map (2) {',
+        '  { a: 1 } => [ \'b\' ],',
+        '  3 => NaN',
+        '}'
+    ].join('\n');
+    var expectedStringTabs = [
+        'Map (2) {',
+        '	{ a: 1 } => [ \'b\' ],',
+        '	3 => NaN',
+        '}'
+    ].join('\n');
+    var expectedStringTabsDoubleQuotes = [
+        'Map (2) {',
+        '	{ a: 1 } => [ "b" ],',
+        '	3 => NaN',
+        '}'
+    ].join('\n');
+
+    t.equal(
+        inspect(map, { indent: 2 }),
+        expectedStringSpaces,
+        'Map keys are not indented (two)'
+    );
+    t.equal(
+        inspect(map, { indent: '\t' }),
+        expectedStringTabs,
+        'Map keys are not indented (tabs)'
+    );
+    t.equal(
+        inspect(map, { indent: '\t', quoteStyle: 'double' }),
+        expectedStringTabsDoubleQuotes,
+        'Map keys are not indented (tabs + double quotes)'
+    );
+
+    t.equal(inspect(new Map(), { indent: 2 }), 'Map (0) {}', 'empty Map should show as empty (two)');
+    t.equal(inspect(new Map(), { indent: '\t' }), 'Map (0) {}', 'empty Map should show as empty (tabs)');
+
+    var nestedMap = new Map();
+    nestedMap.set(nestedMap, map);
+    var expectedNestedSpaces = [
+        'Map (1) {',
+        '  [Circular] => Map (2) {',
+        '    { a: 1 } => [ \'b\' ],',
+        '    3 => NaN',
+        '  }',
+        '}'
+    ].join('\n');
+    var expectedNestedTabs = [
+        'Map (1) {',
+        '	[Circular] => Map (2) {',
+        '		{ a: 1 } => [ \'b\' ],',
+        '		3 => NaN',
+        '	}',
+        '}'
+    ].join('\n');
+    t.equal(inspect(nestedMap, { indent: 2 }), expectedNestedSpaces, 'Map containing a Map should work (two)');
+    t.equal(inspect(nestedMap, { indent: '\t' }), expectedNestedTabs, 'Map containing a Map should work (tabs)');
+
+    t.end();
+});
+
+test('Set', { skip: typeof Set !== 'function' }, function (t) {
+    var set = new Set();
+    set.add({ a: 1 });
+    set.add(['b']);
+    var expectedStringSpaces = [
+        'Set (2) {',
+        '  {',
+        '    a: 1',
+        '  },',
+        '  [ \'b\' ]',
+        '}'
+    ].join('\n');
+    var expectedStringTabs = [
+        'Set (2) {',
+        '	{',
+        '		a: 1',
+        '	},',
+        '	[ \'b\' ]',
+        '}'
+    ].join('\n');
+    t.equal(inspect(set, { indent: 2 }), expectedStringSpaces, 'new Set([{ a: 1 }, ["b"]]) should show size and contents (two)');
+    t.equal(inspect(set, { indent: '\t' }), expectedStringTabs, 'new Set([{ a: 1 }, ["b"]]) should show size and contents (tabs)');
+
+    t.equal(inspect(new Set(), { indent: 2 }), 'Set (0) {}', 'empty Set should show as empty (two)');
+    t.equal(inspect(new Set(), { indent: '\t' }), 'Set (0) {}', 'empty Set should show as empty (tabs)');
+
+    var nestedSet = new Set();
+    nestedSet.add(set);
+    nestedSet.add(nestedSet);
+    var expectedNestedSpaces = [
+        'Set (2) {',
+        '  Set (2) {',
+        '    {',
+        '      a: 1',
+        '    },',
+        '    [ \'b\' ]',
+        '  },',
+        '  [Circular]',
+        '}'
+    ].join('\n');
+    var expectedNestedTabs = [
+        'Set (2) {',
+        '	Set (2) {',
+        '		{',
+        '			a: 1',
+        '		},',
+        '		[ \'b\' ]',
+        '	},',
+        '	[Circular]',
+        '}'
+    ].join('\n');
+    t.equal(inspect(nestedSet, { indent: 2 }), expectedNestedSpaces, 'Set containing a Set should work (two)');
+    t.equal(inspect(nestedSet, { indent: '\t' }), expectedNestedTabs, 'Set containing a Set should work (tabs)');
+
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/test/inspect.js b/server/node_modules/object-inspect/test/inspect.js
new file mode 100644
index 0000000..1abf81b
--- /dev/null
+++ b/server/node_modules/object-inspect/test/inspect.js
@@ -0,0 +1,139 @@
+var test = require('tape');
+var hasSymbols = require('has-symbols/shams')();
+var utilInspect = require('../util.inspect');
+var repeat = require('string.prototype.repeat');
+
+var inspect = require('..');
+
+test('inspect', function (t) {
+    t.plan(5);
+
+    var obj = [{ inspect: function xyzInspect() { return '!XYZ¡'; } }, []];
+    var stringResult = '[ !XYZ¡, [] ]';
+    var falseResult = '[ { inspect: [Function: xyzInspect] }, [] ]';
+
+    t.equal(inspect(obj), stringResult);
+    t.equal(inspect(obj, { customInspect: true }), stringResult);
+    t.equal(inspect(obj, { customInspect: 'symbol' }), falseResult);
+    t.equal(inspect(obj, { customInspect: false }), falseResult);
+    t['throws'](
+        function () { inspect(obj, { customInspect: 'not a boolean or "symbol"' }); },
+        TypeError,
+        '`customInspect` must be a boolean or the string "symbol"'
+    );
+});
+
+test('inspect custom symbol', { skip: !hasSymbols || !utilInspect || !utilInspect.custom }, function (t) {
+    t.plan(4);
+
+    var obj = { inspect: function stringInspect() { return 'string'; } };
+    obj[utilInspect.custom] = function custom() { return 'symbol'; };
+
+    var symbolResult = '[ symbol, [] ]';
+    var stringResult = '[ string, [] ]';
+    var falseResult = '[ { inspect: [Function: stringInspect]' + (utilInspect.custom ? ', [' + inspect(utilInspect.custom) + ']: [Function: custom]' : '') + ' }, [] ]';
+
+    var symbolStringFallback = utilInspect.custom ? symbolResult : stringResult;
+    var symbolFalseFallback = utilInspect.custom ? symbolResult : falseResult;
+
+    t.equal(inspect([obj, []]), symbolStringFallback);
+    t.equal(inspect([obj, []], { customInspect: true }), symbolStringFallback);
+    t.equal(inspect([obj, []], { customInspect: 'symbol' }), symbolFalseFallback);
+    t.equal(inspect([obj, []], { customInspect: false }), falseResult);
+});
+
+test('symbols', { skip: !hasSymbols }, function (t) {
+    t.plan(2);
+
+    var obj = { a: 1 };
+    obj[Symbol('test')] = 2;
+    obj[Symbol.iterator] = 3;
+    Object.defineProperty(obj, Symbol('non-enum'), {
+        enumerable: false,
+        value: 4
+    });
+
+    if (typeof Symbol.iterator === 'symbol') {
+        t.equal(inspect(obj), '{ a: 1, [Symbol(test)]: 2, [Symbol(Symbol.iterator)]: 3 }', 'object with symbols');
+        t.equal(inspect([obj, []]), '[ { a: 1, [Symbol(test)]: 2, [Symbol(Symbol.iterator)]: 3 }, [] ]', 'object with symbols in array');
+    } else {
+        // symbol sham key ordering is unreliable
+        t.match(
+            inspect(obj),
+            /^(?:{ a: 1, \[Symbol$test$\]: 2, \[Symbol$Symbol.iterator$\]: 3 }|{ a: 1, \[Symbol$Symbol.iterator$\]: 3, \[Symbol$test$\]: 2 })$/,
+            'object with symbols (nondeterministic symbol sham key ordering)'
+        );
+        t.match(
+            inspect([obj, []]),
+            /^\[ (?:{ a: 1, \[Symbol$test$\]: 2, \[Symbol$Symbol.iterator$\]: 3 }|{ a: 1, \[Symbol$Symbol.iterator$\]: 3, \[Symbol$test$\]: 2 }), \[\] \]$/,
+            'object with symbols in array (nondeterministic symbol sham key ordering)'
+        );
+    }
+});
+
+test('maxStringLength', function (t) {
+    t['throws'](
+        function () { inspect('', { maxStringLength: -1 }); },
+        TypeError,
+        'maxStringLength must be >= 0, or Infinity, not negative'
+    );
+
+    var str = repeat('a', 1e8);
+
+    t.equal(
+        inspect([str], { maxStringLength: 10 }),
+        '[ \'aaaaaaaaaa\'... 99999990 more characters ]',
+        'maxStringLength option limits output'
+    );
+
+    t.equal(
+        inspect(['f'], { maxStringLength: null }),
+        '[ \'\'... 1 more character ]',
+        'maxStringLength option accepts `null`'
+    );
+
+    t.equal(
+        inspect([str], { maxStringLength: Infinity }),
+        '[ \'' + str + '\' ]',
+        'maxStringLength option accepts ∞'
+    );
+
+    t.end();
+});
+
+test('inspect options', { skip: !utilInspect.custom }, function (t) {
+    var obj = {};
+    obj[utilInspect.custom] = function () {
+        return JSON.stringify(arguments);
+    };
+    t.equal(
+        inspect(obj),
+        utilInspect(obj, { depth: 5 }),
+        'custom symbols will use node\'s inspect'
+    );
+    t.equal(
+        inspect(obj, { depth: 2 }),
+        utilInspect(obj, { depth: 2 }),
+        'a reduced depth will be passed to node\'s inspect'
+    );
+    t.equal(
+        inspect({ d1: obj }, { depth: 3 }),
+        '{ d1: ' + utilInspect(obj, { depth: 2 }) + ' }',
+        'deep objects will receive a reduced depth'
+    );
+    t.equal(
+        inspect({ d1: obj }, { depth: 1 }),
+        '{ d1: [Object] }',
+        'unlike nodejs inspect, customInspect will not be used once the depth is exceeded.'
+    );
+    t.end();
+});
+
+test('inspect URL', { skip: typeof URL === 'undefined' }, function (t) {
+    t.match(
+        inspect(new URL('https://nodejs.org')),
+        /nodejs\.org/, // Different environments stringify it differently
+        'url can be inspected'
+    );
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/test/lowbyte.js b/server/node_modules/object-inspect/test/lowbyte.js
new file mode 100644
index 0000000..68a345d
--- /dev/null
+++ b/server/node_modules/object-inspect/test/lowbyte.js
@@ -0,0 +1,12 @@
+var test = require('tape');
+var inspect = require('../');
+
+var obj = { x: 'a\r\nb', y: '\x05! \x1f \x12' };
+
+test('interpolate low bytes', function (t) {
+    t.plan(1);
+    t.equal(
+        inspect(obj),
+        "{ x: 'a\\r\\nb', y: '\\x05! \\x1F \\x12' }"
+    );
+});
diff --git a/server/node_modules/object-inspect/test/number.js b/server/node_modules/object-inspect/test/number.js
new file mode 100644
index 0000000..8f287e8
--- /dev/null
+++ b/server/node_modules/object-inspect/test/number.js
@@ -0,0 +1,58 @@
+var test = require('tape');
+var v = require('es-value-fixtures');
+var forEach = require('for-each');
+
+var inspect = require('../');
+
+test('negative zero', function (t) {
+    t.equal(inspect(0), '0', 'inspect(0) === "0"');
+    t.equal(inspect(Object(0)), 'Object(0)', 'inspect(Object(0)) === "Object(0)"');
+
+    t.equal(inspect(-0), '-0', 'inspect(-0) === "-0"');
+    t.equal(inspect(Object(-0)), 'Object(-0)', 'inspect(Object(-0)) === "Object(-0)"');
+
+    t.end();
+});
+
+test('numericSeparator', function (t) {
+    forEach(v.nonBooleans, function (nonBoolean) {
+        t['throws'](
+            function () { inspect(true, { numericSeparator: nonBoolean }); },
+            TypeError,
+            inspect(nonBoolean) + ' is not a boolean'
+        );
+    });
+
+    t.test('3 digit numbers', function (st) {
+        var failed = false;
+        for (var i = -999; i < 1000; i += 1) {
+            var actual = inspect(i);
+            var actualSepNo = inspect(i, { numericSeparator: false });
+            var actualSepYes = inspect(i, { numericSeparator: true });
+            var expected = String(i);
+            if (actual !== expected || actualSepNo !== expected || actualSepYes !== expected) {
+                failed = true;
+                t.equal(actual, expected);
+                t.equal(actualSepNo, expected);
+                t.equal(actualSepYes, expected);
+            }
+        }
+
+        st.notOk(failed, 'all 3 digit numbers passed');
+
+        st.end();
+    });
+
+    t.equal(inspect(1e3), '1000', '1000');
+    t.equal(inspect(1e3, { numericSeparator: false }), '1000', '1000, numericSeparator false');
+    t.equal(inspect(1e3, { numericSeparator: true }), '1_000', '1000, numericSeparator true');
+    t.equal(inspect(-1e3), '-1000', '-1000');
+    t.equal(inspect(-1e3, { numericSeparator: false }), '-1000', '-1000, numericSeparator false');
+    t.equal(inspect(-1e3, { numericSeparator: true }), '-1_000', '-1000, numericSeparator true');
+
+    t.equal(inspect(1234.5678, { numericSeparator: true }), '1_234.567_8', 'fractional numbers get separators');
+    t.equal(inspect(1234.56789, { numericSeparator: true }), '1_234.567_89', 'fractional numbers get separators');
+    t.equal(inspect(1234.567891, { numericSeparator: true }), '1_234.567_891', 'fractional numbers get separators');
+
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/test/quoteStyle.js b/server/node_modules/object-inspect/test/quoteStyle.js
new file mode 100644
index 0000000..da23e63
--- /dev/null
+++ b/server/node_modules/object-inspect/test/quoteStyle.js
@@ -0,0 +1,26 @@
+'use strict';
+
+var inspect = require('../');
+var test = require('tape');
+
+test('quoteStyle option', function (t) {
+    t['throws'](function () { inspect(null, { quoteStyle: false }); }, 'false is not a valid value');
+    t['throws'](function () { inspect(null, { quoteStyle: true }); }, 'true is not a valid value');
+    t['throws'](function () { inspect(null, { quoteStyle: '' }); }, '"" is not a valid value');
+    t['throws'](function () { inspect(null, { quoteStyle: {} }); }, '{} is not a valid value');
+    t['throws'](function () { inspect(null, { quoteStyle: [] }); }, '[] is not a valid value');
+    t['throws'](function () { inspect(null, { quoteStyle: 42 }); }, '42 is not a valid value');
+    t['throws'](function () { inspect(null, { quoteStyle: NaN }); }, 'NaN is not a valid value');
+    t['throws'](function () { inspect(null, { quoteStyle: function () {} }); }, 'a function is not a valid value');
+
+    t.equal(inspect('"', { quoteStyle: 'single' }), '\'"\'', 'double quote, quoteStyle: "single"');
+    t.equal(inspect('"', { quoteStyle: 'double' }), '"\\""', 'double quote, quoteStyle: "double"');
+
+    t.equal(inspect('\'', { quoteStyle: 'single' }), '\'\\\'\'', 'single quote, quoteStyle: "single"');
+    t.equal(inspect('\'', { quoteStyle: 'double' }), '"\'"', 'single quote, quoteStyle: "double"');
+
+    t.equal(inspect('`', { quoteStyle: 'single' }), '\'`\'', 'backtick, quoteStyle: "single"');
+    t.equal(inspect('`', { quoteStyle: 'double' }), '"`"', 'backtick, quoteStyle: "double"');
+
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/test/toStringTag.js b/server/node_modules/object-inspect/test/toStringTag.js
new file mode 100644
index 0000000..95f8270
--- /dev/null
+++ b/server/node_modules/object-inspect/test/toStringTag.js
@@ -0,0 +1,40 @@
+'use strict';
+
+var test = require('tape');
+var hasToStringTag = require('has-tostringtag/shams')();
+
+var inspect = require('../');
+
+test('Symbol.toStringTag', { skip: !hasToStringTag }, function (t) {
+    t.plan(4);
+
+    var obj = { a: 1 };
+    t.equal(inspect(obj), '{ a: 1 }', 'object, no Symbol.toStringTag');
+
+    obj[Symbol.toStringTag] = 'foo';
+    t.equal(inspect(obj), '{ a: 1, [Symbol(Symbol.toStringTag)]: \'foo\' }', 'object with Symbol.toStringTag');
+
+    t.test('null objects', { skip: 'toString' in { __proto__: null } }, function (st) {
+        st.plan(2);
+
+        var dict = { __proto__: null, a: 1 };
+        st.equal(inspect(dict), '[Object: null prototype] { a: 1 }', 'null object with Symbol.toStringTag');
+
+        dict[Symbol.toStringTag] = 'Dict';
+        st.equal(inspect(dict), '[Dict: null prototype] { a: 1, [Symbol(Symbol.toStringTag)]: \'Dict\' }', 'null object with Symbol.toStringTag');
+    });
+
+    t.test('instances', function (st) {
+        st.plan(4);
+
+        function C() {
+            this.a = 1;
+        }
+        st.equal(Object.prototype.toString.call(new C()), '[object Object]', 'instance, no toStringTag, Object.prototype.toString');
+        st.equal(inspect(new C()), 'C { a: 1 }', 'instance, no toStringTag');
+
+        C.prototype[Symbol.toStringTag] = 'Class!';
+        st.equal(Object.prototype.toString.call(new C()), '[object Class!]', 'instance, with toStringTag, Object.prototype.toString');
+        st.equal(inspect(new C()), 'C [Class!] { a: 1 }', 'instance, with toStringTag');
+    });
+});
diff --git a/server/node_modules/object-inspect/test/undef.js b/server/node_modules/object-inspect/test/undef.js
new file mode 100644
index 0000000..e3f4961
--- /dev/null
+++ b/server/node_modules/object-inspect/test/undef.js
@@ -0,0 +1,12 @@
+var test = require('tape');
+var inspect = require('../');
+
+var obj = { a: 1, b: [3, 4, undefined, null], c: undefined, d: null };
+
+test('undef and null', function (t) {
+    t.plan(1);
+    t.equal(
+        inspect(obj),
+        '{ a: 1, b: [ 3, 4, undefined, null ], c: undefined, d: null }'
+    );
+});
diff --git a/server/node_modules/object-inspect/test/values.js b/server/node_modules/object-inspect/test/values.js
new file mode 100644
index 0000000..15986cd
--- /dev/null
+++ b/server/node_modules/object-inspect/test/values.js
@@ -0,0 +1,261 @@
+'use strict';
+
+var inspect = require('../');
+var test = require('tape');
+var mockProperty = require('mock-property');
+var hasSymbols = require('has-symbols/shams')();
+var hasToStringTag = require('has-tostringtag/shams')();
+var forEach = require('for-each');
+var semver = require('semver');
+
+test('values', function (t) {
+    t.plan(1);
+    var obj = [{}, [], { 'a-b': 5 }];
+    t.equal(inspect(obj), '[ {}, [], { \'a-b\': 5 } ]');
+});
+
+test('arrays with properties', function (t) {
+    t.plan(1);
+    var arr = [3];
+    arr.foo = 'bar';
+    var obj = [1, 2, arr];
+    obj.baz = 'quux';
+    obj.index = -1;
+    t.equal(inspect(obj), '[ 1, 2, [ 3, foo: \'bar\' ], baz: \'quux\', index: -1 ]');
+});
+
+test('has', function (t) {
+    t.plan(1);
+    t.teardown(mockProperty(Object.prototype, 'hasOwnProperty', { 'delete': true }));
+
+    t.equal(inspect({ a: 1, b: 2 }), '{ a: 1, b: 2 }');
+});
+
+test('indexOf seen', function (t) {
+    t.plan(1);
+    var xs = [1, 2, 3, {}];
+    xs.push(xs);
+
+    var seen = [];
+    seen.indexOf = undefined;
+
+    t.equal(
+        inspect(xs, {}, 0, seen),
+        '[ 1, 2, 3, {}, [Circular] ]'
+    );
+});
+
+test('seen seen', function (t) {
+    t.plan(1);
+    var xs = [1, 2, 3];
+
+    var seen = [xs];
+    seen.indexOf = undefined;
+
+    t.equal(
+        inspect(xs, {}, 0, seen),
+        '[Circular]'
+    );
+});
+
+test('seen seen seen', function (t) {
+    t.plan(1);
+    var xs = [1, 2, 3];
+
+    var seen = [5, xs];
+    seen.indexOf = undefined;
+
+    t.equal(
+        inspect(xs, {}, 0, seen),
+        '[Circular]'
+    );
+});
+
+test('symbols', { skip: !hasSymbols }, function (t) {
+    var sym = Symbol('foo');
+    t.equal(inspect(sym), 'Symbol(foo)', 'Symbol("foo") should be "Symbol(foo)"');
+    if (typeof sym === 'symbol') {
+        // Symbol shams are incapable of differentiating boxed from unboxed symbols
+        t.equal(inspect(Object(sym)), 'Object(Symbol(foo))', 'Object(Symbol("foo")) should be "Object(Symbol(foo))"');
+    }
+
+    t.test('toStringTag', { skip: !hasToStringTag }, function (st) {
+        st.plan(1);
+
+        var faker = {};
+        faker[Symbol.toStringTag] = 'Symbol';
+        st.equal(
+            inspect(faker),
+            '{ [Symbol(Symbol.toStringTag)]: \'Symbol\' }',
+            'object lying about being a Symbol inspects as an object'
+        );
+    });
+
+    t.end();
+});
+
+test('Map', { skip: typeof Map !== 'function' }, function (t) {
+    var map = new Map();
+    map.set({ a: 1 }, ['b']);
+    map.set(3, NaN);
+    var expectedString = 'Map (2) {' + inspect({ a: 1 }) + ' => ' + inspect(['b']) + ', 3 => NaN}';
+    t.equal(inspect(map), expectedString, 'new Map([[{ a: 1 }, ["b"]], [3, NaN]]) should show size and contents');
+    t.equal(inspect(new Map()), 'Map (0) {}', 'empty Map should show as empty');
+
+    var nestedMap = new Map();
+    nestedMap.set(nestedMap, map);
+    t.equal(inspect(nestedMap), 'Map (1) {[Circular] => ' + expectedString + '}', 'Map containing a Map should work');
+
+    t.end();
+});
+
+test('WeakMap', { skip: typeof WeakMap !== 'function' }, function (t) {
+    var map = new WeakMap();
+    map.set({ a: 1 }, ['b']);
+    var expectedString = 'WeakMap { ? }';
+    t.equal(inspect(map), expectedString, 'new WeakMap([[{ a: 1 }, ["b"]]]) should not show size or contents');
+    t.equal(inspect(new WeakMap()), 'WeakMap { ? }', 'empty WeakMap should not show as empty');
+
+    t.end();
+});
+
+test('Set', { skip: typeof Set !== 'function' }, function (t) {
+    var set = new Set();
+    set.add({ a: 1 });
+    set.add(['b']);
+    var expectedString = 'Set (2) {' + inspect({ a: 1 }) + ', ' + inspect(['b']) + '}';
+    t.equal(inspect(set), expectedString, 'new Set([{ a: 1 }, ["b"]]) should show size and contents');
+    t.equal(inspect(new Set()), 'Set (0) {}', 'empty Set should show as empty');
+
+    var nestedSet = new Set();
+    nestedSet.add(set);
+    nestedSet.add(nestedSet);
+    t.equal(inspect(nestedSet), 'Set (2) {' + expectedString + ', [Circular]}', 'Set containing a Set should work');
+
+    t.end();
+});
+
+test('WeakSet', { skip: typeof WeakSet !== 'function' }, function (t) {
+    var map = new WeakSet();
+    map.add({ a: 1 });
+    var expectedString = 'WeakSet { ? }';
+    t.equal(inspect(map), expectedString, 'new WeakSet([{ a: 1 }]) should not show size or contents');
+    t.equal(inspect(new WeakSet()), 'WeakSet { ? }', 'empty WeakSet should not show as empty');
+
+    t.end();
+});
+
+test('WeakRef', { skip: typeof WeakRef !== 'function' }, function (t) {
+    var ref = new WeakRef({ a: 1 });
+    var expectedString = 'WeakRef { ? }';
+    t.equal(inspect(ref), expectedString, 'new WeakRef({ a: 1 }) should not show contents');
+
+    t.end();
+});
+
+test('FinalizationRegistry', { skip: typeof FinalizationRegistry !== 'function' }, function (t) {
+    var registry = new FinalizationRegistry(function () {});
+    var expectedString = 'FinalizationRegistry [FinalizationRegistry] {}';
+    t.equal(inspect(registry), expectedString, 'new FinalizationRegistry(function () {}) should work normallys');
+
+    t.end();
+});
+
+test('Strings', function (t) {
+    var str = 'abc';
+
+    t.equal(inspect(str), "'" + str + "'", 'primitive string shows as such');
+    t.equal(inspect(str, { quoteStyle: 'single' }), "'" + str + "'", 'primitive string shows as such, single quoted');
+    t.equal(inspect(str, { quoteStyle: 'double' }), '"' + str + '"', 'primitive string shows as such, double quoted');
+    t.equal(inspect(Object(str)), 'Object(' + inspect(str) + ')', 'String object shows as such');
+    t.equal(inspect(Object(str), { quoteStyle: 'single' }), 'Object(' + inspect(str, { quoteStyle: 'single' }) + ')', 'String object shows as such, single quoted');
+    t.equal(inspect(Object(str), { quoteStyle: 'double' }), 'Object(' + inspect(str, { quoteStyle: 'double' }) + ')', 'String object shows as such, double quoted');
+
+    t.end();
+});
+
+test('Numbers', function (t) {
+    var num = 42;
+
+    t.equal(inspect(num), String(num), 'primitive number shows as such');
+    t.equal(inspect(Object(num)), 'Object(' + inspect(num) + ')', 'Number object shows as such');
+
+    t.end();
+});
+
+test('Booleans', function (t) {
+    t.equal(inspect(true), String(true), 'primitive true shows as such');
+    t.equal(inspect(Object(true)), 'Object(' + inspect(true) + ')', 'Boolean object true shows as such');
+
+    t.equal(inspect(false), String(false), 'primitive false shows as such');
+    t.equal(inspect(Object(false)), 'Object(' + inspect(false) + ')', 'Boolean false object shows as such');
+
+    t.end();
+});
+
+test('Date', function (t) {
+    var now = new Date();
+    t.equal(inspect(now), String(now), 'Date shows properly');
+    t.equal(inspect(new Date(NaN)), 'Invalid Date', 'Invalid Date shows properly');
+
+    t.end();
+});
+
+test('RegExps', function (t) {
+    t.equal(inspect(/a/g), '/a/g', 'regex shows properly');
+    t.equal(inspect(new RegExp('abc', 'i')), '/abc/i', 'new RegExp shows properly');
+
+    var match = 'abc abc'.match(/[ab]+/);
+    delete match.groups; // for node < 10
+    t.equal(inspect(match), '[ \'ab\', index: 0, input: \'abc abc\' ]', 'RegExp match object shows properly');
+
+    t.end();
+});
+
+test('Proxies', { skip: typeof Proxy !== 'function' || !hasToStringTag }, function (t) {
+    var target = { proxy: true };
+    var fake = new Proxy(target, { has: function () { return false; } });
+
+    // needed to work around a weird difference in node v6.0 - v6.4 where non-present properties are not logged
+    var isNode60 = semver.satisfies(process.version, '6.0 - 6.4');
+
+    forEach([
+        'Boolean',
+        'Number',
+        'String',
+        'Symbol',
+        'Date'
+    ], function (tag) {
+        target[Symbol.toStringTag] = tag;
+
+        t.equal(
+            inspect(fake),
+            '{ ' + (isNode60 ? '' : 'proxy: true, ') + '[Symbol(Symbol.toStringTag)]: \'' + tag + '\' }',
+            'Proxy for + ' + tag + ' shows as the target, which has no slots'
+        );
+    });
+
+    t.end();
+});
+
+test('fakers', { skip: !hasToStringTag }, function (t) {
+    var target = { proxy: false };
+
+    forEach([
+        'Boolean',
+        'Number',
+        'String',
+        'Symbol',
+        'Date'
+    ], function (tag) {
+        target[Symbol.toStringTag] = tag;
+
+        t.equal(
+            inspect(target),
+            '{ proxy: false, [Symbol(Symbol.toStringTag)]: \'' + tag + '\' }',
+            'Object pretending to be ' + tag + ' does not trick us'
+        );
+    });
+
+    t.end();
+});
diff --git a/server/node_modules/object-inspect/util.inspect.js b/server/node_modules/object-inspect/util.inspect.js
new file mode 100644
index 0000000..7784fab
--- /dev/null
+++ b/server/node_modules/object-inspect/util.inspect.js
@@ -0,0 +1 @@
+module.exports = require('util').inspect;
diff --git a/server/node_modules/on-finished/HISTORY.md b/server/node_modules/on-finished/HISTORY.md
new file mode 100644
index 0000000..1917595
--- /dev/null
+++ b/server/node_modules/on-finished/HISTORY.md
@@ -0,0 +1,98 @@
+2.4.1 / 2022-02-22
+==================
+
+  * Fix error on early async hooks implementations
+
+2.4.0 / 2022-02-21
+==================
+
+  * Prevent loss of async hooks context
+
+2.3.0 / 2015-05-26
+==================
+
+  * Add defined behavior for HTTP `CONNECT` requests
+  * Add defined behavior for HTTP `Upgrade` requests
+  * deps: ee-first@1.1.1
+
+2.2.1 / 2015-04-22
+==================
+
+  * Fix `isFinished(req)` when data buffered
+
+2.2.0 / 2014-12-22
+==================
+
+  * Add message object to callback arguments
+
+2.1.1 / 2014-10-22
+==================
+
+  * Fix handling of pipelined requests
+
+2.1.0 / 2014-08-16
+==================
+
+  * Check if `socket` is detached
+  * Return `undefined` for `isFinished` if state unknown
+
+2.0.0 / 2014-08-16
+==================
+
+  * Add `isFinished` function
+  * Move to `jshttp` organization
+  * Remove support for plain socket argument
+  * Rename to `on-finished`
+  * Support both `req` and `res` as arguments
+  * deps: ee-first@1.0.5
+
+1.2.2 / 2014-06-10
+==================
+
+  * Reduce listeners added to emitters
+    - avoids "event emitter leak" warnings when used multiple times on same request
+
+1.2.1 / 2014-06-08
+==================
+
+  * Fix returned value when already finished
+
+1.2.0 / 2014-06-05
+==================
+
+  * Call callback when called on already-finished socket
+
+1.1.4 / 2014-05-27
+==================
+
+  * Support node.js 0.8
+
+1.1.3 / 2014-04-30
+==================
+
+  * Make sure errors passed as instanceof `Error`
+
+1.1.2 / 2014-04-18
+==================
+
+  * Default the `socket` to passed-in object
+
+1.1.1 / 2014-01-16
+==================
+
+  * Rename module to `finished`
+
+1.1.0 / 2013-12-25
+==================
+
+  * Call callback when called on already-errored socket
+
+1.0.1 / 2013-12-20
+==================
+
+  * Actually pass the error to the callback
+
+1.0.0 / 2013-12-20
+==================
+
+  * Initial release
diff --git a/server/node_modules/on-finished/LICENSE b/server/node_modules/on-finished/LICENSE
new file mode 100644
index 0000000..5931fd2
--- /dev/null
+++ b/server/node_modules/on-finished/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2013 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2014 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/on-finished/README.md b/server/node_modules/on-finished/README.md
new file mode 100644
index 0000000..8973cde
--- /dev/null
+++ b/server/node_modules/on-finished/README.md
@@ -0,0 +1,162 @@
+# on-finished
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][ci-image]][ci-url]
+[![Coverage Status][coveralls-image]][coveralls-url]
+
+Execute a callback when a HTTP request closes, finishes, or errors.
+
+## Install
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install on-finished
+```
+
+## API
+
+```js
+var onFinished = require('on-finished')
+```
+
+### onFinished(res, listener)
+
+Attach a listener to listen for the response to finish. The listener will
+be invoked only once when the response finished. If the response finished
+to an error, the first argument will contain the error. If the response
+has already finished, the listener will be invoked.
+
+Listening to the end of a response would be used to close things associated
+with the response, like open files.
+
+Listener is invoked as `listener(err, res)`.
+
+
+
+```js
+onFinished(res, function (err, res) {
+  // clean up open fds, etc.
+  // err contains the error if request error'd
+})
+```
+
+### onFinished(req, listener)
+
+Attach a listener to listen for the request to finish. The listener will
+be invoked only once when the request finished. If the request finished
+to an error, the first argument will contain the error. If the request
+has already finished, the listener will be invoked.
+
+Listening to the end of a request would be used to know when to continue
+after reading the data.
+
+Listener is invoked as `listener(err, req)`.
+
+
+
+```js
+var data = ''
+
+req.setEncoding('utf8')
+req.on('data', function (str) {
+  data += str
+})
+
+onFinished(req, function (err, req) {
+  // data is read unless there is err
+})
+```
+
+### onFinished.isFinished(res)
+
+Determine if `res` is already finished. This would be useful to check and
+not even start certain operations if the response has already finished.
+
+### onFinished.isFinished(req)
+
+Determine if `req` is already finished. This would be useful to check and
+not even start certain operations if the request has already finished.
+
+## Special Node.js requests
+
+### HTTP CONNECT method
+
+The meaning of the `CONNECT` method from RFC 7231, section 4.3.6:
+
+> The CONNECT method requests that the recipient establish a tunnel to
+> the destination origin server identified by the request-target and,
+> if successful, thereafter restrict its behavior to blind forwarding
+> of packets, in both directions, until the tunnel is closed.  Tunnels
+> are commonly used to create an end-to-end virtual connection, through
+> one or more proxies, which can then be secured using TLS (Transport
+> Layer Security, [RFC5246]).
+
+In Node.js, these request objects come from the `'connect'` event on
+the HTTP server.
+
+When this module is used on a HTTP `CONNECT` request, the request is
+considered "finished" immediately, **due to limitations in the Node.js
+interface**. This means if the `CONNECT` request contains a request entity,
+the request will be considered "finished" even before it has been read.
+
+There is no such thing as a response object to a `CONNECT` request in
+Node.js, so there is no support for one.
+
+### HTTP Upgrade request
+
+The meaning of the `Upgrade` header from RFC 7230, section 6.1:
+
+> The "Upgrade" header field is intended to provide a simple mechanism
+> for transitioning from HTTP/1.1 to some other protocol on the same
+> connection.
+
+In Node.js, these request objects come from the `'upgrade'` event on
+the HTTP server.
+
+When this module is used on a HTTP request with an `Upgrade` header, the
+request is considered "finished" immediately, **due to limitations in the
+Node.js interface**. This means if the `Upgrade` request contains a request
+entity, the request will be considered "finished" even before it has been
+read.
+
+There is no such thing as a response object to a `Upgrade` request in
+Node.js, so there is no support for one.
+
+## Example
+
+The following code ensures that file descriptors are always closed
+once the response finishes.
+
+```js
+var destroy = require('destroy')
+var fs = require('fs')
+var http = require('http')
+var onFinished = require('on-finished')
+
+http.createServer(function onRequest (req, res) {
+  var stream = fs.createReadStream('package.json')
+  stream.pipe(res)
+  onFinished(res, function () {
+    destroy(stream)
+  })
+})
+```
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/jshttp/on-finished/master?label=ci
+[ci-url]: https://github.com/jshttp/on-finished/actions/workflows/ci.yml
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/on-finished/master
+[coveralls-url]: https://coveralls.io/r/jshttp/on-finished?branch=master
+[node-image]: https://badgen.net/npm/node/on-finished
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/on-finished
+[npm-url]: https://npmjs.org/package/on-finished
+[npm-version-image]: https://badgen.net/npm/v/on-finished
diff --git a/server/node_modules/on-finished/index.js b/server/node_modules/on-finished/index.js
new file mode 100644
index 0000000..e68df7b
--- /dev/null
+++ b/server/node_modules/on-finished/index.js
@@ -0,0 +1,234 @@
+/*!
+ * on-finished
+ * Copyright(c) 2013 Jonathan Ong
+ * Copyright(c) 2014 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = onFinished
+module.exports.isFinished = isFinished
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var asyncHooks = tryRequireAsyncHooks()
+var first = require('ee-first')
+
+/**
+ * Variables.
+ * @private
+ */
+
+/* istanbul ignore next */
+var defer = typeof setImmediate === 'function'
+  ? setImmediate
+  : function (fn) { process.nextTick(fn.bind.apply(fn, arguments)) }
+
+/**
+ * Invoke callback when the response has finished, useful for
+ * cleaning up resources afterwards.
+ *
+ * @param {object} msg
+ * @param {function} listener
+ * @return {object}
+ * @public
+ */
+
+function onFinished (msg, listener) {
+  if (isFinished(msg) !== false) {
+    defer(listener, null, msg)
+    return msg
+  }
+
+  // attach the listener to the message
+  attachListener(msg, wrap(listener))
+
+  return msg
+}
+
+/**
+ * Determine if message is already finished.
+ *
+ * @param {object} msg
+ * @return {boolean}
+ * @public
+ */
+
+function isFinished (msg) {
+  var socket = msg.socket
+
+  if (typeof msg.finished === 'boolean') {
+    // OutgoingMessage
+    return Boolean(msg.finished || (socket && !socket.writable))
+  }
+
+  if (typeof msg.complete === 'boolean') {
+    // IncomingMessage
+    return Boolean(msg.upgrade || !socket || !socket.readable || (msg.complete && !msg.readable))
+  }
+
+  // don't know
+  return undefined
+}
+
+/**
+ * Attach a finished listener to the message.
+ *
+ * @param {object} msg
+ * @param {function} callback
+ * @private
+ */
+
+function attachFinishedListener (msg, callback) {
+  var eeMsg
+  var eeSocket
+  var finished = false
+
+  function onFinish (error) {
+    eeMsg.cancel()
+    eeSocket.cancel()
+
+    finished = true
+    callback(error)
+  }
+
+  // finished on first message event
+  eeMsg = eeSocket = first([[msg, 'end', 'finish']], onFinish)
+
+  function onSocket (socket) {
+    // remove listener
+    msg.removeListener('socket', onSocket)
+
+    if (finished) return
+    if (eeMsg !== eeSocket) return
+
+    // finished on first socket event
+    eeSocket = first([[socket, 'error', 'close']], onFinish)
+  }
+
+  if (msg.socket) {
+    // socket already assigned
+    onSocket(msg.socket)
+    return
+  }
+
+  // wait for socket to be assigned
+  msg.on('socket', onSocket)
+
+  if (msg.socket === undefined) {
+    // istanbul ignore next: node.js 0.8 patch
+    patchAssignSocket(msg, onSocket)
+  }
+}
+
+/**
+ * Attach the listener to the message.
+ *
+ * @param {object} msg
+ * @return {function}
+ * @private
+ */
+
+function attachListener (msg, listener) {
+  var attached = msg.__onFinished
+
+  // create a private single listener with queue
+  if (!attached || !attached.queue) {
+    attached = msg.__onFinished = createListener(msg)
+    attachFinishedListener(msg, attached)
+  }
+
+  attached.queue.push(listener)
+}
+
+/**
+ * Create listener on message.
+ *
+ * @param {object} msg
+ * @return {function}
+ * @private
+ */
+
+function createListener (msg) {
+  function listener (err) {
+    if (msg.__onFinished === listener) msg.__onFinished = null
+    if (!listener.queue) return
+
+    var queue = listener.queue
+    listener.queue = null
+
+    for (var i = 0; i < queue.length; i++) {
+      queue[i](err, msg)
+    }
+  }
+
+  listener.queue = []
+
+  return listener
+}
+
+/**
+ * Patch ServerResponse.prototype.assignSocket for node.js 0.8.
+ *
+ * @param {ServerResponse} res
+ * @param {function} callback
+ * @private
+ */
+
+// istanbul ignore next: node.js 0.8 patch
+function patchAssignSocket (res, callback) {
+  var assignSocket = res.assignSocket
+
+  if (typeof assignSocket !== 'function') return
+
+  // res.on('socket', callback) is broken in 0.8
+  res.assignSocket = function _assignSocket (socket) {
+    assignSocket.call(this, socket)
+    callback(socket)
+  }
+}
+
+/**
+ * Try to require async_hooks
+ * @private
+ */
+
+function tryRequireAsyncHooks () {
+  try {
+    return require('async_hooks')
+  } catch (e) {
+    return {}
+  }
+}
+
+/**
+ * Wrap function with async resource, if possible.
+ * AsyncResource.bind static method backported.
+ * @private
+ */
+
+function wrap (fn) {
+  var res
+
+  // create anonymous resource
+  if (asyncHooks.AsyncResource) {
+    res = new asyncHooks.AsyncResource(fn.name || 'bound-anonymous-fn')
+  }
+
+  // incompatible node.js
+  if (!res || !res.runInAsyncScope) {
+    return fn
+  }
+
+  // return bound function
+  return res.runInAsyncScope.bind(res, fn, null)
+}
diff --git a/server/node_modules/on-finished/package.json b/server/node_modules/on-finished/package.json
new file mode 100644
index 0000000..644cd81
--- /dev/null
+++ b/server/node_modules/on-finished/package.json
@@ -0,0 +1,39 @@
+{
+  "name": "on-finished",
+  "description": "Execute a callback when a request closes, finishes, or errors",
+  "version": "2.4.1",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "license": "MIT",
+  "repository": "jshttp/on-finished",
+  "dependencies": {
+    "ee-first": "1.1.1"
+  },
+  "devDependencies": {
+    "eslint": "7.32.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.25.4",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "5.2.0",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "9.2.1",
+    "nyc": "15.1.0"
+  },
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "index.js"
+  ],
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-ci": "nyc --reporter=lcovonly --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/on-headers/HISTORY.md b/server/node_modules/on-headers/HISTORY.md
new file mode 100644
index 0000000..a77a6aa
--- /dev/null
+++ b/server/node_modules/on-headers/HISTORY.md
@@ -0,0 +1,26 @@
+1.1.0 / 2025-07-17
+==================
+  * - Fix [CVE-2025-7339](https://www.cve.org/CVERecord?id=CVE-2025-7339) ([GHSA-76c9-3jph-rj3q](https://github.com/expressjs/multer/security/advisories/GHSA-76c9-3jph-rj3q))
+
+
+1.0.2 / 2019-02-21
+==================
+
+  * Fix `res.writeHead` patch missing return value
+
+1.0.1 / 2015-09-29
+==================
+
+  * perf: enable strict mode
+
+1.0.0 / 2014-08-10
+==================
+
+  * Honor `res.statusCode` change in `listener`
+  * Move to `jshttp` organization
+  * Prevent `arguments`-related de-opt
+
+0.0.0 / 2014-05-13
+==================
+
+  * Initial implementation
diff --git a/server/node_modules/on-headers/LICENSE b/server/node_modules/on-headers/LICENSE
new file mode 100644
index 0000000..b7dce6c
--- /dev/null
+++ b/server/node_modules/on-headers/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2014 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/on-headers/README.md b/server/node_modules/on-headers/README.md
new file mode 100644
index 0000000..865fe4b
--- /dev/null
+++ b/server/node_modules/on-headers/README.md
@@ -0,0 +1,81 @@
+# on-headers
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][ci-image]][ci-url]
+[![Coverage Status][coveralls-image]][coveralls-url]
+
+Execute a listener when a response is about to write headers.
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install on-headers
+```
+
+## API
+
+
+
+```js
+var onHeaders = require('on-headers')
+```
+
+### onHeaders(res, listener)
+
+This will add the listener `listener` to fire when headers are emitted for `res`.
+The listener is passed the `response` object as it's context (`this`). Headers are
+considered to be emitted only once, right before they are sent to the client.
+
+When this is called multiple times on the same `res`, the `listener`s are fired
+in the reverse order they were added.
+
+## Examples
+
+```js
+var http = require('http')
+var onHeaders = require('on-headers')
+
+http
+  .createServer(onRequest)
+  .listen(3000)
+
+function addPoweredBy () {
+  // set if not set by end of request
+  if (!this.getHeader('X-Powered-By')) {
+    this.setHeader('X-Powered-By', 'Node.js')
+  }
+}
+
+function onRequest (req, res) {
+  onHeaders(res, addPoweredBy)
+
+  res.setHeader('Content-Type', 'text/plain')
+  res.end('hello!')
+}
+```
+
+## Testing
+
+```sh
+$ npm test
+```
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/jshttp/on-headers/master?label=ci
+[ci-url]: https://github.com/jshttp/on-headers/actions/workflows/ci.yml
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/on-headers/master
+[coveralls-url]: https://coveralls.io/r/jshttp/on-headers?branch=master
+[node-image]: https://badgen.net/npm/node/on-headers
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/on-headers
+[npm-url]: https://npmjs.org/package/on-headers
+[npm-version-image]: https://badgen.net/npm/v/on-headers
diff --git a/server/node_modules/on-headers/index.js b/server/node_modules/on-headers/index.js
new file mode 100644
index 0000000..d691cc7
--- /dev/null
+++ b/server/node_modules/on-headers/index.js
@@ -0,0 +1,180 @@
+/*!
+ * on-headers
+ * Copyright(c) 2014 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = onHeaders
+
+var http = require('http')
+
+// older node versions don't have appendHeader
+var isAppendHeaderSupported = typeof http.ServerResponse.prototype.appendHeader === 'function'
+var set1dArray = isAppendHeaderSupported ? set1dArrayWithAppend : set1dArrayWithSet
+
+/**
+ * Create a replacement writeHead method.
+ *
+ * @param {function} prevWriteHead
+ * @param {function} listener
+ * @private
+ */
+
+function createWriteHead (prevWriteHead, listener) {
+  var fired = false
+
+  // return function with core name and argument list
+  return function writeHead (statusCode) {
+    // set headers from arguments
+    var args = setWriteHeadHeaders.apply(this, arguments)
+
+    // fire listener
+    if (!fired) {
+      fired = true
+      listener.call(this)
+
+      // pass-along an updated status code
+      if (typeof args[0] === 'number' && this.statusCode !== args[0]) {
+        args[0] = this.statusCode
+        args.length = 1
+      }
+    }
+
+    return prevWriteHead.apply(this, args)
+  }
+}
+
+/**
+ * Execute a listener when a response is about to write headers.
+ *
+ * @param {object} res
+ * @return {function} listener
+ * @public
+ */
+
+function onHeaders (res, listener) {
+  if (!res) {
+    throw new TypeError('argument res is required')
+  }
+
+  if (typeof listener !== 'function') {
+    throw new TypeError('argument listener must be a function')
+  }
+
+  res.writeHead = createWriteHead(res.writeHead, listener)
+}
+
+/**
+ * Set headers contained in array on the response object.
+ *
+ * @param {object} res
+ * @param {array} headers
+ * @private
+ */
+
+function setHeadersFromArray (res, headers) {
+  if (headers.length && Array.isArray(headers[0])) {
+    // 2D
+    set2dArray(res, headers)
+  } else {
+    // 1D
+    if (headers.length % 2 !== 0) {
+      throw new TypeError('headers array is malformed')
+    }
+
+    set1dArray(res, headers)
+  }
+}
+
+/**
+ * Set headers contained in object on the response object.
+ *
+ * @param {object} res
+ * @param {object} headers
+ * @private
+ */
+
+function setHeadersFromObject (res, headers) {
+  var keys = Object.keys(headers)
+  for (var i = 0; i < keys.length; i++) {
+    var k = keys[i]
+    if (k) res.setHeader(k, headers[k])
+  }
+}
+
+/**
+ * Set headers and other properties on the response object.
+ *
+ * @param {number} statusCode
+ * @private
+ */
+
+function setWriteHeadHeaders (statusCode) {
+  var length = arguments.length
+  var headerIndex = length > 1 && typeof arguments[1] === 'string'
+    ? 2
+    : 1
+
+  var headers = length >= headerIndex + 1
+    ? arguments[headerIndex]
+    : undefined
+
+  this.statusCode = statusCode
+
+  if (Array.isArray(headers)) {
+    // handle array case
+    setHeadersFromArray(this, headers)
+  } else if (headers) {
+    // handle object case
+    setHeadersFromObject(this, headers)
+  }
+
+  // copy leading arguments
+  var args = new Array(Math.min(length, headerIndex))
+  for (var i = 0; i < args.length; i++) {
+    args[i] = arguments[i]
+  }
+
+  return args
+}
+
+function set2dArray (res, headers) {
+  var key
+  for (var i = 0; i < headers.length; i++) {
+    key = headers[i][0]
+    if (key) {
+      res.setHeader(key, headers[i][1])
+    }
+  }
+}
+
+function set1dArrayWithAppend (res, headers) {
+  for (var i = 0; i < headers.length; i += 2) {
+    res.removeHeader(headers[i])
+  }
+
+  var key
+  for (var j = 0; j < headers.length; j += 2) {
+    key = headers[j]
+    if (key) {
+      res.appendHeader(key, headers[j + 1])
+    }
+  }
+}
+
+function set1dArrayWithSet (res, headers) {
+  var key
+  for (var i = 0; i < headers.length; i += 2) {
+    key = headers[i]
+    if (key) {
+      res.setHeader(key, headers[i + 1])
+    }
+  }
+}
diff --git a/server/node_modules/on-headers/package.json b/server/node_modules/on-headers/package.json
new file mode 100644
index 0000000..341ce2f
--- /dev/null
+++ b/server/node_modules/on-headers/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "on-headers",
+  "description": "Execute a listener when a response is about to write headers",
+  "version": "1.1.0",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "keywords": [
+    "event",
+    "headers",
+    "http",
+    "onheaders"
+  ],
+  "repository": "jshttp/on-headers",
+  "devDependencies": {
+    "eslint": "6.8.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.21.2",
+    "eslint-plugin-markdown": "1.0.2",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "4.2.1",
+    "eslint-plugin-standard": "4.0.1",
+    "mocha": "10.2.0",
+    "nyc": "15.1.0",
+    "supertest": "4.0.2"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec --check-leaks test/test.js",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "update-upstream-hashes": "node scripts/update-upstream-hashes.js",
+    "upstream": "mocha --reporter spec --check-leaks test/upstream.js",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  }
+}
diff --git a/server/node_modules/once/LICENSE b/server/node_modules/once/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/once/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/once/README.md b/server/node_modules/once/README.md
new file mode 100644
index 0000000..1f1ffca
--- /dev/null
+++ b/server/node_modules/once/README.md
@@ -0,0 +1,79 @@
+# once
+
+Only call a function once.
+
+## usage
+
+```javascript
+var once = require('once')
+
+function load (file, cb) {
+  cb = once(cb)
+  loader.load('file')
+  loader.once('load', cb)
+  loader.once('error', cb)
+}
+```
+
+Or add to the Function.prototype in a responsible way:
+
+```javascript
+// only has to be done once
+require('once').proto()
+
+function load (file, cb) {
+  cb = cb.once()
+  loader.load('file')
+  loader.once('load', cb)
+  loader.once('error', cb)
+}
+```
+
+Ironically, the prototype feature makes this module twice as
+complicated as necessary.
+
+To check whether you function has been called, use `fn.called`. Once the
+function is called for the first time the return value of the original
+function is saved in `fn.value` and subsequent calls will continue to
+return this value.
+
+```javascript
+var once = require('once')
+
+function load (cb) {
+  cb = once(cb)
+  var stream = createStream()
+  stream.once('data', cb)
+  stream.once('end', function () {
+    if (!cb.called) cb(new Error('not found'))
+  })
+}
+```
+
+## `once.strict(func)`
+
+Throw an error if the function is called twice.
+
+Some functions are expected to be called only once. Using `once` for them would
+potentially hide logical errors.
+
+In the example below, the `greet` function has to call the callback only once:
+
+```javascript
+function greet (name, cb) {
+  // return is missing from the if statement
+  // when no name is passed, the callback is called twice
+  if (!name) cb('Hello anonymous')
+  cb('Hello ' + name)
+}
+
+function log (msg) {
+  console.log(msg)
+}
+
+// this will print 'Hello anonymous' but the logical error will be missed
+greet(null, once(msg))
+
+// once.strict will print 'Hello anonymous' and throw an error when the callback will be called the second time
+greet(null, once.strict(msg))
+```
diff --git a/server/node_modules/once/once.js b/server/node_modules/once/once.js
new file mode 100644
index 0000000..2354067
--- /dev/null
+++ b/server/node_modules/once/once.js
@@ -0,0 +1,42 @@
+var wrappy = require('wrappy')
+module.exports = wrappy(once)
+module.exports.strict = wrappy(onceStrict)
+
+once.proto = once(function () {
+  Object.defineProperty(Function.prototype, 'once', {
+    value: function () {
+      return once(this)
+    },
+    configurable: true
+  })
+
+  Object.defineProperty(Function.prototype, 'onceStrict', {
+    value: function () {
+      return onceStrict(this)
+    },
+    configurable: true
+  })
+})
+
+function once (fn) {
+  var f = function () {
+    if (f.called) return f.value
+    f.called = true
+    return f.value = fn.apply(this, arguments)
+  }
+  f.called = false
+  return f
+}
+
+function onceStrict (fn) {
+  var f = function () {
+    if (f.called)
+      throw new Error(f.onceError)
+    f.called = true
+    return f.value = fn.apply(this, arguments)
+  }
+  var name = fn.name || 'Function wrapped with `once`'
+  f.onceError = name + " shouldn't be called more than once"
+  f.called = false
+  return f
+}
diff --git a/server/node_modules/once/package.json b/server/node_modules/once/package.json
new file mode 100644
index 0000000..16815b2
--- /dev/null
+++ b/server/node_modules/once/package.json
@@ -0,0 +1,33 @@
+{
+  "name": "once",
+  "version": "1.4.0",
+  "description": "Run a function exactly one time",
+  "main": "once.js",
+  "directories": {
+    "test": "test"
+  },
+  "dependencies": {
+    "wrappy": "1"
+  },
+  "devDependencies": {
+    "tap": "^7.0.1"
+  },
+  "scripts": {
+    "test": "tap test/*.js"
+  },
+  "files": [
+    "once.js"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/isaacs/once"
+  },
+  "keywords": [
+    "once",
+    "function",
+    "one",
+    "single"
+  ],
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC"
+}
diff --git a/server/node_modules/p-map/index.d.ts b/server/node_modules/p-map/index.d.ts
new file mode 100644
index 0000000..bcbe0af
--- /dev/null
+++ b/server/node_modules/p-map/index.d.ts
@@ -0,0 +1,67 @@
+declare namespace pMap {
+	interface Options {
+		/**
+		Number of concurrently pending promises returned by `mapper`.
+
+		Must be an integer from 1 and up or `Infinity`.
+
+		@default Infinity
+		*/
+		readonly concurrency?: number;
+
+		/**
+		When set to `false`, instead of stopping when a promise rejects, it will wait for all the promises to settle and then reject with an [aggregated error](https://github.com/sindresorhus/aggregate-error) containing all the errors from the rejected promises.
+
+		@default true
+		*/
+		readonly stopOnError?: boolean;
+	}
+
+	/**
+	Function which is called for every item in `input`. Expected to return a `Promise` or value.
+
+	@param element - Iterated element.
+	@param index - Index of the element in the source array.
+	*/
+	type Mapper<Element = any, NewElement = unknown> = (
+		element: Element,
+		index: number
+	) => NewElement | Promise<NewElement>;
+}
+
+/**
+@param input - Iterated over concurrently in the `mapper` function.
+@param mapper - Function which is called for every item in `input`. Expected to return a `Promise` or value.
+@returns A `Promise` that is fulfilled when all promises in `input` and ones returned from `mapper` are fulfilled, or rejects if any of the promises reject. The fulfilled value is an `Array` of the fulfilled values returned from `mapper` in `input` order.
+
+@example
+```
+import pMap = require('p-map');
+import got = require('got');
+
+const sites = [
+	getWebsiteFromUsername('https://sindresorhus'), //=> Promise
+	'https://ava.li',
+	'https://github.com'
+];
+
+(async () => {
+	const mapper = async site => {
+		const {requestUrl} = await got.head(site);
+		return requestUrl;
+	};
+
+	const result = await pMap(sites, mapper, {concurrency: 2});
+
+	console.log(result);
+	//=> ['https://sindresorhus.com/', 'https://ava.li/', 'https://github.com/']
+})();
+```
+*/
+declare function pMap<Element, NewElement>(
+	input: Iterable<Element>,
+	mapper: pMap.Mapper<Element, NewElement>,
+	options?: pMap.Options
+): Promise<NewElement[]>;
+
+export = pMap;
diff --git a/server/node_modules/p-map/index.js b/server/node_modules/p-map/index.js
new file mode 100644
index 0000000..c11a285
--- /dev/null
+++ b/server/node_modules/p-map/index.js
@@ -0,0 +1,81 @@
+'use strict';
+const AggregateError = require('aggregate-error');
+
+module.exports = async (
+	iterable,
+	mapper,
+	{
+		concurrency = Infinity,
+		stopOnError = true
+	} = {}
+) => {
+	return new Promise((resolve, reject) => {
+		if (typeof mapper !== 'function') {
+			throw new TypeError('Mapper function is required');
+		}
+
+		if (!((Number.isSafeInteger(concurrency) || concurrency === Infinity) && concurrency >= 1)) {
+			throw new TypeError(`Expected \`concurrency\` to be an integer from 1 and up or \`Infinity\`, got \`${concurrency}\` (${typeof concurrency})`);
+		}
+
+		const result = [];
+		const errors = [];
+		const iterator = iterable[Symbol.iterator]();
+		let isRejected = false;
+		let isIterableDone = false;
+		let resolvingCount = 0;
+		let currentIndex = 0;
+
+		const next = () => {
+			if (isRejected) {
+				return;
+			}
+
+			const nextItem = iterator.next();
+			const index = currentIndex;
+			currentIndex++;
+
+			if (nextItem.done) {
+				isIterableDone = true;
+
+				if (resolvingCount === 0) {
+					if (!stopOnError && errors.length !== 0) {
+						reject(new AggregateError(errors));
+					} else {
+						resolve(result);
+					}
+				}
+
+				return;
+			}
+
+			resolvingCount++;
+
+			(async () => {
+				try {
+					const element = await nextItem.value;
+					result[index] = await mapper(element, index);
+					resolvingCount--;
+					next();
+				} catch (error) {
+					if (stopOnError) {
+						isRejected = true;
+						reject(error);
+					} else {
+						errors.push(error);
+						resolvingCount--;
+						next();
+					}
+				}
+			})();
+		};
+
+		for (let i = 0; i < concurrency; i++) {
+			next();
+
+			if (isIterableDone) {
+				break;
+			}
+		}
+	});
+};
diff --git a/server/node_modules/p-map/license b/server/node_modules/p-map/license
new file mode 100644
index 0000000..fa7ceba
--- /dev/null
+++ b/server/node_modules/p-map/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/p-map/package.json b/server/node_modules/p-map/package.json
new file mode 100644
index 0000000..042b1af
--- /dev/null
+++ b/server/node_modules/p-map/package.json
@@ -0,0 +1,53 @@
+{
+	"name": "p-map",
+	"version": "4.0.0",
+	"description": "Map over promises concurrently",
+	"license": "MIT",
+	"repository": "sindresorhus/p-map",
+	"funding": "https://github.com/sponsors/sindresorhus",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "https://sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=10"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"promise",
+		"map",
+		"resolved",
+		"wait",
+		"collection",
+		"iterable",
+		"iterator",
+		"race",
+		"fulfilled",
+		"async",
+		"await",
+		"promises",
+		"concurrently",
+		"concurrency",
+		"parallel",
+		"bluebird"
+	],
+	"dependencies": {
+		"aggregate-error": "^3.0.0"
+	},
+	"devDependencies": {
+		"ava": "^2.2.0",
+		"delay": "^4.1.0",
+		"in-range": "^2.0.0",
+		"random-int": "^2.0.0",
+		"time-span": "^3.1.0",
+		"tsd": "^0.7.4",
+		"xo": "^0.27.2"
+	}
+}
diff --git a/server/node_modules/p-map/readme.md b/server/node_modules/p-map/readme.md
new file mode 100644
index 0000000..53a3715
--- /dev/null
+++ b/server/node_modules/p-map/readme.md
@@ -0,0 +1,89 @@
+# p-map [![Build Status](https://travis-ci.org/sindresorhus/p-map.svg?branch=master)](https://travis-ci.org/sindresorhus/p-map)
+
+> Map over promises concurrently
+
+Useful when you need to run promise-returning & async functions multiple times with different inputs concurrently.
+
+## Install
+
+```
+$ npm install p-map
+```
+
+## Usage
+
+```js
+const pMap = require('p-map');
+const got = require('got');
+
+const sites = [
+	getWebsiteFromUsername('https://sindresorhus'), //=> Promise
+	'https://ava.li',
+	'https://github.com'
+];
+
+(async () => {
+	const mapper = async site => {
+		const {requestUrl} = await got.head(site);
+		return requestUrl;
+	};
+
+ 	const result = await pMap(sites, mapper, {concurrency: 2});
+
+	console.log(result);
+	//=> ['https://sindresorhus.com/', 'https://ava.li/', 'https://github.com/']
+})();
+```
+
+## API
+
+### pMap(input, mapper, options?)
+
+Returns a `Promise` that is fulfilled when all promises in `input` and ones returned from `mapper` are fulfilled, or rejects if any of the promises reject. The fulfilled value is an `Array` of the fulfilled values returned from `mapper` in `input` order.
+
+#### input
+
+Type: `Iterable<Promise | unknown>`
+
+Iterated over concurrently in the `mapper` function.
+
+#### mapper(element, index)
+
+Type: `Function`
+
+Expected to return a `Promise` or value.
+
+#### options
+
+Type: `object`
+
+##### concurrency
+
+Type: `number` (Integer)\
+Default: `Infinity`\
+Minimum: `1`
+
+Number of concurrently pending promises returned by `mapper`.
+
+##### stopOnError
+
+Type: `boolean`\
+Default: `true`
+
+When set to `false`, instead of stopping when a promise rejects, it will wait for all the promises to settle and then reject with an [aggregated error](https://github.com/sindresorhus/aggregate-error) containing all the errors from the rejected promises.
+
+## p-map for enterprise
+
+Available as part of the Tidelift Subscription.
+
+The maintainers of p-map and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. [Learn more.](https://tidelift.com/subscription/pkg/npm-p-map?utm_source=npm-p-map&utm_medium=referral&utm_campaign=enterprise&utm_term=repo)
+
+## Related
+
+- [p-all](https://github.com/sindresorhus/p-all) - Run promise-returning & async functions concurrently with optional limited concurrency
+- [p-filter](https://github.com/sindresorhus/p-filter) - Filter promises concurrently
+- [p-times](https://github.com/sindresorhus/p-times) - Run promise-returning & async functions a specific number of times concurrently
+- [p-props](https://github.com/sindresorhus/p-props) - Like `Promise.all()` but for `Map` and `Object`
+- [p-map-series](https://github.com/sindresorhus/p-map-series) - Map over promises serially
+- [p-queue](https://github.com/sindresorhus/p-queue) - Promise queue with concurrency control
+- [More…](https://github.com/sindresorhus/promise-fun)
diff --git a/server/node_modules/parseurl/HISTORY.md b/server/node_modules/parseurl/HISTORY.md
new file mode 100644
index 0000000..8e40954
--- /dev/null
+++ b/server/node_modules/parseurl/HISTORY.md
@@ -0,0 +1,58 @@
+1.3.3 / 2019-04-15
+==================
+
+  * Fix Node.js 0.8 return value inconsistencies
+
+1.3.2 / 2017-09-09
+==================
+
+  * perf: reduce overhead for full URLs
+  * perf: unroll the "fast-path" `RegExp`
+
+1.3.1 / 2016-01-17
+==================
+
+  * perf: enable strict mode
+
+1.3.0 / 2014-08-09
+==================
+
+  * Add `parseurl.original` for parsing `req.originalUrl` with fallback
+  * Return `undefined` if `req.url` is `undefined`
+
+1.2.0 / 2014-07-21
+==================
+
+  * Cache URLs based on original value
+  * Remove no-longer-needed URL mis-parse work-around
+  * Simplify the "fast-path" `RegExp`
+
+1.1.3 / 2014-07-08
+==================
+
+  * Fix typo
+
+1.1.2 / 2014-07-08
+==================
+
+  * Seriously fix Node.js 0.8 compatibility
+
+1.1.1 / 2014-07-08
+==================
+
+  * Fix Node.js 0.8 compatibility
+
+1.1.0 / 2014-07-08
+==================
+
+  * Incorporate URL href-only parse fast-path
+
+1.0.1 / 2014-03-08
+==================
+
+  * Add missing `require`
+
+1.0.0 / 2014-03-08
+==================
+
+  * Genesis from `connect`
diff --git a/server/node_modules/parseurl/LICENSE b/server/node_modules/parseurl/LICENSE
new file mode 100644
index 0000000..27653d3
--- /dev/null
+++ b/server/node_modules/parseurl/LICENSE
@@ -0,0 +1,24 @@
+
+(The MIT License)
+
+Copyright (c) 2014 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2014-2017 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/parseurl/README.md b/server/node_modules/parseurl/README.md
new file mode 100644
index 0000000..443e716
--- /dev/null
+++ b/server/node_modules/parseurl/README.md
@@ -0,0 +1,133 @@
+# parseurl
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Parse a URL with memoization.
+
+## Install
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install parseurl
+```
+
+## API
+
+```js
+var parseurl = require('parseurl')
+```
+
+### parseurl(req)
+
+Parse the URL of the given request object (looks at the `req.url` property)
+and return the result. The result is the same as `url.parse` in Node.js core.
+Calling this function multiple times on the same `req` where `req.url` does
+not change will return a cached parsed object, rather than parsing again.
+
+### parseurl.original(req)
+
+Parse the original URL of the given request object and return the result.
+This works by trying to parse `req.originalUrl` if it is a string, otherwise
+parses `req.url`. The result is the same as `url.parse` in Node.js core.
+Calling this function multiple times on the same `req` where `req.originalUrl`
+does not change will return a cached parsed object, rather than parsing again.
+
+## Benchmark
+
+```bash
+$ npm run-script bench
+
+> parseurl@1.3.3 bench nodejs-parseurl
+> node benchmark/index.js
+
+  http_parser@2.8.0
+  node@10.6.0
+  v8@6.7.288.46-node.13
+  uv@1.21.0
+  zlib@1.2.11
+  ares@1.14.0
+  modules@64
+  nghttp2@1.32.0
+  napi@3
+  openssl@1.1.0h
+  icu@61.1
+  unicode@10.0
+  cldr@33.0
+  tz@2018c
+
+> node benchmark/fullurl.js
+
+  Parsing URL "http://localhost:8888/foo/bar?user=tj&pet=fluffy"
+
+  4 tests completed.
+
+  fasturl            x 2,207,842 ops/sec ±3.76% (184 runs sampled)
+  nativeurl - legacy x   507,180 ops/sec ±0.82% (191 runs sampled)
+  nativeurl - whatwg x   290,044 ops/sec ±1.96% (189 runs sampled)
+  parseurl           x   488,907 ops/sec ±2.13% (192 runs sampled)
+
+> node benchmark/pathquery.js
+
+  Parsing URL "/foo/bar?user=tj&pet=fluffy"
+
+  4 tests completed.
+
+  fasturl            x 3,812,564 ops/sec ±3.15% (188 runs sampled)
+  nativeurl - legacy x 2,651,631 ops/sec ±1.68% (189 runs sampled)
+  nativeurl - whatwg x   161,837 ops/sec ±2.26% (189 runs sampled)
+  parseurl           x 4,166,338 ops/sec ±2.23% (184 runs sampled)
+
+> node benchmark/samerequest.js
+
+  Parsing URL "/foo/bar?user=tj&pet=fluffy" on same request object
+
+  4 tests completed.
+
+  fasturl            x  3,821,651 ops/sec ±2.42% (185 runs sampled)
+  nativeurl - legacy x  2,651,162 ops/sec ±1.90% (187 runs sampled)
+  nativeurl - whatwg x    175,166 ops/sec ±1.44% (188 runs sampled)
+  parseurl           x 14,912,606 ops/sec ±3.59% (183 runs sampled)
+
+> node benchmark/simplepath.js
+
+  Parsing URL "/foo/bar"
+
+  4 tests completed.
+
+  fasturl            x 12,421,765 ops/sec ±2.04% (191 runs sampled)
+  nativeurl - legacy x  7,546,036 ops/sec ±1.41% (188 runs sampled)
+  nativeurl - whatwg x    198,843 ops/sec ±1.83% (189 runs sampled)
+  parseurl           x 24,244,006 ops/sec ±0.51% (194 runs sampled)
+
+> node benchmark/slash.js
+
+  Parsing URL "/"
+
+  4 tests completed.
+
+  fasturl            x 17,159,456 ops/sec ±3.25% (188 runs sampled)
+  nativeurl - legacy x 11,635,097 ops/sec ±3.79% (184 runs sampled)
+  nativeurl - whatwg x    240,693 ops/sec ±0.83% (189 runs sampled)
+  parseurl           x 42,279,067 ops/sec ±0.55% (190 runs sampled)
+```
+
+## License
+
+  [MIT](LICENSE)
+
+[coveralls-image]: https://badgen.net/coveralls/c/github/pillarjs/parseurl/master
+[coveralls-url]: https://coveralls.io/r/pillarjs/parseurl?branch=master
+[node-image]: https://badgen.net/npm/node/parseurl
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/parseurl
+[npm-url]: https://npmjs.org/package/parseurl
+[npm-version-image]: https://badgen.net/npm/v/parseurl
+[travis-image]: https://badgen.net/travis/pillarjs/parseurl/master
+[travis-url]: https://travis-ci.org/pillarjs/parseurl
diff --git a/server/node_modules/parseurl/index.js b/server/node_modules/parseurl/index.js
new file mode 100644
index 0000000..ece7223
--- /dev/null
+++ b/server/node_modules/parseurl/index.js
@@ -0,0 +1,158 @@
+/*!
+ * parseurl
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2014-2017 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var url = require('url')
+var parse = url.parse
+var Url = url.Url
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = parseurl
+module.exports.original = originalurl
+
+/**
+ * Parse the `req` url with memoization.
+ *
+ * @param {ServerRequest} req
+ * @return {Object}
+ * @public
+ */
+
+function parseurl (req) {
+  var url = req.url
+
+  if (url === undefined) {
+    // URL is undefined
+    return undefined
+  }
+
+  var parsed = req._parsedUrl
+
+  if (fresh(url, parsed)) {
+    // Return cached URL parse
+    return parsed
+  }
+
+  // Parse the URL
+  parsed = fastparse(url)
+  parsed._raw = url
+
+  return (req._parsedUrl = parsed)
+};
+
+/**
+ * Parse the `req` original url with fallback and memoization.
+ *
+ * @param {ServerRequest} req
+ * @return {Object}
+ * @public
+ */
+
+function originalurl (req) {
+  var url = req.originalUrl
+
+  if (typeof url !== 'string') {
+    // Fallback
+    return parseurl(req)
+  }
+
+  var parsed = req._parsedOriginalUrl
+
+  if (fresh(url, parsed)) {
+    // Return cached URL parse
+    return parsed
+  }
+
+  // Parse the URL
+  parsed = fastparse(url)
+  parsed._raw = url
+
+  return (req._parsedOriginalUrl = parsed)
+};
+
+/**
+ * Parse the `str` url with fast-path short-cut.
+ *
+ * @param {string} str
+ * @return {Object}
+ * @private
+ */
+
+function fastparse (str) {
+  if (typeof str !== 'string' || str.charCodeAt(0) !== 0x2f /* / */) {
+    return parse(str)
+  }
+
+  var pathname = str
+  var query = null
+  var search = null
+
+  // This takes the regexp from https://github.com/joyent/node/pull/7878
+  // Which is /^(\/[^?#\s]*)(\?[^#\s]*)?$/
+  // And unrolls it into a for loop
+  for (var i = 1; i < str.length; i++) {
+    switch (str.charCodeAt(i)) {
+      case 0x3f: /* ?  */
+        if (search === null) {
+          pathname = str.substring(0, i)
+          query = str.substring(i + 1)
+          search = str.substring(i)
+        }
+        break
+      case 0x09: /* \t */
+      case 0x0a: /* \n */
+      case 0x0c: /* \f */
+      case 0x0d: /* \r */
+      case 0x20: /*    */
+      case 0x23: /* #  */
+      case 0xa0:
+      case 0xfeff:
+        return parse(str)
+    }
+  }
+
+  var url = Url !== undefined
+    ? new Url()
+    : {}
+
+  url.path = str
+  url.href = str
+  url.pathname = pathname
+
+  if (search !== null) {
+    url.query = query
+    url.search = search
+  }
+
+  return url
+}
+
+/**
+ * Determine if parsed is still fresh for url.
+ *
+ * @param {string} url
+ * @param {object} parsedUrl
+ * @return {boolean}
+ * @private
+ */
+
+function fresh (url, parsedUrl) {
+  return typeof parsedUrl === 'object' &&
+    parsedUrl !== null &&
+    (Url === undefined || parsedUrl instanceof Url) &&
+    parsedUrl._raw === url
+}
diff --git a/server/node_modules/parseurl/package.json b/server/node_modules/parseurl/package.json
new file mode 100644
index 0000000..6b443ca
--- /dev/null
+++ b/server/node_modules/parseurl/package.json
@@ -0,0 +1,40 @@
+{
+  "name": "parseurl",
+  "description": "parse a url with memoization",
+  "version": "1.3.3",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "repository": "pillarjs/parseurl",
+  "license": "MIT",
+  "devDependencies": {
+    "beautify-benchmark": "0.2.4",
+    "benchmark": "2.1.4",
+    "eslint": "5.16.0",
+    "eslint-config-standard": "12.0.0",
+    "eslint-plugin-import": "2.17.1",
+    "eslint-plugin-node": "7.0.1",
+    "eslint-plugin-promise": "4.1.1",
+    "eslint-plugin-standard": "4.0.0",
+    "fast-url-parser": "1.1.3",
+    "istanbul": "0.4.5",
+    "mocha": "6.1.3"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint .",
+    "test": "mocha --check-leaks --bail --reporter spec test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --check-leaks --reporter dot test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --check-leaks --reporter spec test/"
+  }
+}
diff --git a/server/node_modules/path-is-absolute/index.js b/server/node_modules/path-is-absolute/index.js
new file mode 100644
index 0000000..22aa6c3
--- /dev/null
+++ b/server/node_modules/path-is-absolute/index.js
@@ -0,0 +1,20 @@
+'use strict';
+
+function posix(path) {
+	return path.charAt(0) === '/';
+}
+
+function win32(path) {
+	// https://github.com/nodejs/node/blob/b3fcc245fb25539909ef1d5eaa01dbf92e168633/lib/path.js#L56
+	var splitDeviceRe = /^([a-zA-Z]:|[\\\/]{2}[^\\\/]+[\\\/]+[^\\\/]+)?([\\\/])?([\s\S]*?)$/;
+	var result = splitDeviceRe.exec(path);
+	var device = result[1] || '';
+	var isUnc = Boolean(device && device.charAt(1) !== ':');
+
+	// UNC paths are always absolute
+	return Boolean(result[2] || isUnc);
+}
+
+module.exports = process.platform === 'win32' ? win32 : posix;
+module.exports.posix = posix;
+module.exports.win32 = win32;
diff --git a/server/node_modules/path-is-absolute/license b/server/node_modules/path-is-absolute/license
new file mode 100644
index 0000000..654d0bf
--- /dev/null
+++ b/server/node_modules/path-is-absolute/license
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/path-is-absolute/package.json b/server/node_modules/path-is-absolute/package.json
new file mode 100644
index 0000000..91196d5
--- /dev/null
+++ b/server/node_modules/path-is-absolute/package.json
@@ -0,0 +1,43 @@
+{
+  "name": "path-is-absolute",
+  "version": "1.0.1",
+  "description": "Node.js 0.12 path.isAbsolute() ponyfill",
+  "license": "MIT",
+  "repository": "sindresorhus/path-is-absolute",
+  "author": {
+    "name": "Sindre Sorhus",
+    "email": "sindresorhus@gmail.com",
+    "url": "sindresorhus.com"
+  },
+  "engines": {
+    "node": ">=0.10.0"
+  },
+  "scripts": {
+    "test": "xo && node test.js"
+  },
+  "files": [
+    "index.js"
+  ],
+  "keywords": [
+    "path",
+    "paths",
+    "file",
+    "dir",
+    "absolute",
+    "isabsolute",
+    "is-absolute",
+    "built-in",
+    "util",
+    "utils",
+    "core",
+    "ponyfill",
+    "polyfill",
+    "shim",
+    "is",
+    "detect",
+    "check"
+  ],
+  "devDependencies": {
+    "xo": "^0.16.0"
+  }
+}
diff --git a/server/node_modules/path-is-absolute/readme.md b/server/node_modules/path-is-absolute/readme.md
new file mode 100644
index 0000000..8dbdf5f
--- /dev/null
+++ b/server/node_modules/path-is-absolute/readme.md
@@ -0,0 +1,59 @@
+# path-is-absolute [![Build Status](https://travis-ci.org/sindresorhus/path-is-absolute.svg?branch=master)](https://travis-ci.org/sindresorhus/path-is-absolute)
+
+> Node.js 0.12 [`path.isAbsolute()`](http://nodejs.org/api/path.html#path_path_isabsolute_path) [ponyfill](https://ponyfill.com)
+
+
+## Install
+
+```
+$ npm install --save path-is-absolute
+```
+
+
+## Usage
+
+```js
+const pathIsAbsolute = require('path-is-absolute');
+
+// Running on Linux
+pathIsAbsolute('/home/foo');
+//=> true
+pathIsAbsolute('C:/Users/foo');
+//=> false
+
+// Running on Windows
+pathIsAbsolute('C:/Users/foo');
+//=> true
+pathIsAbsolute('/home/foo');
+//=> false
+
+// Running on any OS
+pathIsAbsolute.posix('/home/foo');
+//=> true
+pathIsAbsolute.posix('C:/Users/foo');
+//=> false
+pathIsAbsolute.win32('C:/Users/foo');
+//=> true
+pathIsAbsolute.win32('/home/foo');
+//=> false
+```
+
+
+## API
+
+See the [`path.isAbsolute()` docs](http://nodejs.org/api/path.html#path_path_isabsolute_path).
+
+### pathIsAbsolute(path)
+
+### pathIsAbsolute.posix(path)
+
+POSIX specific version.
+
+### pathIsAbsolute.win32(path)
+
+Windows specific version.
+
+
+## License
+
+MIT © [Sindre Sorhus](https://sindresorhus.com)
diff --git a/server/node_modules/path-to-regexp/LICENSE b/server/node_modules/path-to-regexp/LICENSE
new file mode 100644
index 0000000..983fbe8
--- /dev/null
+++ b/server/node_modules/path-to-regexp/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Blake Embrey (hello@blakeembrey.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/path-to-regexp/Readme.md b/server/node_modules/path-to-regexp/Readme.md
new file mode 100644
index 0000000..95452a6
--- /dev/null
+++ b/server/node_modules/path-to-regexp/Readme.md
@@ -0,0 +1,35 @@
+# Path-to-RegExp
+
+Turn an Express-style path string such as `/user/:name` into a regular expression.
+
+**Note:** This is a legacy branch. You should upgrade to `1.x`.
+
+## Usage
+
+```javascript
+var pathToRegexp = require('path-to-regexp');
+```
+
+### pathToRegexp(path, keys, options)
+
+ - **path** A string in the express format, an array of such strings, or a regular expression
+ - **keys** An array to be populated with the keys present in the url.  Once the function completes, this will be an array of strings.
+ - **options**
+   - **options.sensitive** Defaults to false, set this to true to make routes case sensitive
+   - **options.strict** Defaults to false, set this to true to make the trailing slash matter.
+   - **options.end** Defaults to true, set this to false to only match the prefix of the URL.
+
+```javascript
+var keys = [];
+var exp = pathToRegexp('/foo/:bar', keys);
+//keys = ['bar']
+//exp = /^\/foo\/(?:([^\/]+?))\/?$/i
+```
+
+## Live Demo
+
+You can see a live demo of this library in use at [express-route-tester](http://forbeslindesay.github.com/express-route-tester/).
+
+## License
+
+  MIT
diff --git a/server/node_modules/path-to-regexp/index.js b/server/node_modules/path-to-regexp/index.js
new file mode 100644
index 0000000..95d2f4b
--- /dev/null
+++ b/server/node_modules/path-to-regexp/index.js
@@ -0,0 +1,156 @@
+/**
+ * Expose `pathToRegexp`.
+ */
+
+module.exports = pathToRegexp;
+
+/**
+ * Match matching groups in a regular expression.
+ */
+var MATCHING_GROUP_REGEXP = /\\.|\((?:\?<(.*?)>)?(?!\?)/g;
+
+/**
+ * Normalize the given path string,
+ * returning a regular expression.
+ *
+ * An empty array should be passed,
+ * which will contain the placeholder
+ * key names. For example "/user/:id" will
+ * then contain ["id"].
+ *
+ * @param  {String|RegExp|Array} path
+ * @param  {Array} keys
+ * @param  {Object} options
+ * @return {RegExp}
+ * @api private
+ */
+
+function pathToRegexp(path, keys, options) {
+  options = options || {};
+  keys = keys || [];
+  var strict = options.strict;
+  var end = options.end !== false;
+  var flags = options.sensitive ? '' : 'i';
+  var lookahead = options.lookahead !== false;
+  var extraOffset = 0;
+  var keysOffset = keys.length;
+  var i = 0;
+  var name = 0;
+  var pos = 0;
+  var backtrack = '';
+  var m;
+
+  if (path instanceof RegExp) {
+    while (m = MATCHING_GROUP_REGEXP.exec(path.source)) {
+      if (m[0][0] === '\\') continue;
+
+      keys.push({
+        name: m[1] || name++,
+        optional: false,
+        offset: m.index
+      });
+    }
+
+    return path;
+  }
+
+  if (Array.isArray(path)) {
+    // Map array parts into regexps and return their source. We also pass
+    // the same keys and options instance into every generation to get
+    // consistent matching groups before we join the sources together.
+    path = path.map(function (value) {
+      return pathToRegexp(value, keys, options).source;
+    });
+
+    return new RegExp(path.join('|'), flags);
+  }
+
+  if (typeof path !== 'string') {
+    throw new TypeError('path must be a string, array of strings, or regular expression');
+  }
+
+  path = path.replace(
+    /\\.|(\/)?(\.)?:(\w+)($.*?$)?(\*)?(\?)?|[.*]|\/\(/g,
+    function (match, slash, format, key, capture, star, optional, offset) {
+      if (match[0] === '\\') {
+        backtrack += match;
+        pos += 2;
+        return match;
+      }
+
+      if (match === '.') {
+        backtrack += '\\.';
+        extraOffset += 1;
+        pos += 1;
+        return '\\.';
+      }
+
+      if (slash || format) {
+        backtrack = '';
+      } else {
+        backtrack += path.slice(pos, offset);
+      }
+
+      pos = offset + match.length;
+
+      if (match === '*') {
+        extraOffset += 3;
+        return '(.*)';
+      }
+
+      if (match === '/(') {
+        backtrack += '/';
+        extraOffset += 2;
+        return '/(?:';
+      }
+
+      slash = slash || '';
+      format = format ? '\\.' : '';
+      optional = optional || '';
+      capture = capture ?
+        capture.replace(/\\.|\*/, function (m) { return m === '*' ? '(.*)' : m; }) :
+        (backtrack ? '((?:(?!/|' + backtrack + ').)+?)' : '([^/' + format + ']+?)');
+
+      keys.push({
+        name: key,
+        optional: !!optional,
+        offset: offset + extraOffset
+      });
+
+      var result = '(?:'
+        + format + slash + capture
+        + (star ? '((?:[/' + format + '].+?)?)' : '')
+        + ')'
+        + optional;
+
+      extraOffset += result.length - match.length;
+
+      return result;
+    });
+
+  // This is a workaround for handling unnamed matching groups.
+  while (m = MATCHING_GROUP_REGEXP.exec(path)) {
+    if (m[0][0] === '\\') continue;
+
+    if (keysOffset + i === keys.length || keys[keysOffset + i].offset > m.index) {
+      keys.splice(keysOffset + i, 0, {
+        name: name++, // Unnamed matching groups must be consistently linear.
+        optional: false,
+        offset: m.index
+      });
+    }
+
+    i++;
+  }
+
+  path += strict ? '' : path[path.length - 1] === '/' ? '?' : '/?';
+
+  // If the path is non-ending, match until the end or a slash.
+  if (end) {
+    path += '$';
+  } else if (path[path.length - 1] !== '/') {
+    path += lookahead ? '(?=/|$)' : '(?:/|$)';
+  }
+
+  return new RegExp('^' + path, flags);
+};
diff --git a/server/node_modules/path-to-regexp/package.json b/server/node_modules/path-to-regexp/package.json
new file mode 100644
index 0000000..23b4b6a
--- /dev/null
+++ b/server/node_modules/path-to-regexp/package.json
@@ -0,0 +1,30 @@
+{
+  "name": "path-to-regexp",
+  "description": "Express style path to RegExp utility",
+  "version": "0.1.12",
+  "files": [
+    "index.js",
+    "LICENSE"
+  ],
+  "scripts": {
+    "test": "istanbul cover _mocha -- -R spec"
+  },
+  "keywords": [
+    "express",
+    "regexp"
+  ],
+  "component": {
+    "scripts": {
+      "path-to-regexp": "index.js"
+    }
+  },
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/pillarjs/path-to-regexp.git"
+  },
+  "devDependencies": {
+    "mocha": "^1.17.1",
+    "istanbul": "^0.2.6"
+  }
+}
diff --git a/server/node_modules/prebuild-install/CHANGELOG.md b/server/node_modules/prebuild-install/CHANGELOG.md
new file mode 100644
index 0000000..03cd97a
--- /dev/null
+++ b/server/node_modules/prebuild-install/CHANGELOG.md
@@ -0,0 +1,131 @@
+# Changelog
+
+## [7.1.3] - 2025-01-22
+
+### Fixed
+
+- Bump napi-build-utils from 1 to 2 ([#204](https://github.com/prebuild/prebuild-install/issues/204)) ([`1bf4a15`](https://github.com/prebuild/prebuild-install/commit/1bf4a15)) (Bailey Pearson)
+
+## [7.1.2] - 2024-02-29
+
+### Fixed
+
+- Support environments where MD5 is prohibited ([#191](https://github.com/prebuild/prebuild-install/issues/191)) ([`9140468`](https://github.com/prebuild/prebuild-install/commit/9140468)) (Tomasz Szuba)
+
+## [7.1.1] - 2022-06-07
+
+### Fixed
+
+- Replace use of npmlog dependency with console.error ([#182](https://github.com/prebuild/prebuild-install/issues/182)) ([`4e2284c`](https://github.com/prebuild/prebuild-install/commit/4e2284c)) (Lovell Fuller)
+- Ensure script output can be captured by tests ([#181](https://github.com/prebuild/prebuild-install/issues/181)) ([`d1853cb`](https://github.com/prebuild/prebuild-install/commit/d1853cb)) (Lovell Fuller)
+
+## [7.1.0] - 2022-04-20
+
+### Changed
+
+- Allow setting libc to glibc on non-glibc platform ([#176](https://github.com/prebuild/prebuild-install/issues/176)) ([`f729abb`](https://github.com/prebuild/prebuild-install/commit/f729abb)) (Joona Heinikoski)
+
+## [7.0.1] - 2022-01-28
+
+### Changed
+
+- Upgrade to the latest version of `detect-libc` ([#166](https://github.com/prebuild/prebuild-install/issues/166)) ([`f71c6b9`](https://github.com/prebuild/prebuild-install/commit/f71c6b9)) (Lovell Fuller)
+
+## [7.0.0] - 2021-11-12
+
+### Changed
+
+- **Breaking:** bump `node-abi` so that Electron 14+ gets correct ABI ([#161](https://github.com/prebuild/prebuild-install/issues/161)) ([`477f347`](https://github.com/prebuild/prebuild-install/commit/477f347)) (csett86). Drops support of Node.js < 10.
+- Bump `simple-get` ([`7468c14`](https://github.com/prebuild/prebuild-install/commit/7468c14)) (Vincent Weevers).
+
+## [6.1.4] - 2021-08-11
+
+### Fixed
+
+- Move auth token to header instead of query param ([#160](https://github.com/prebuild/prebuild-install/issues/160)) ([`b3fad76`](https://github.com/prebuild/prebuild-install/commit/b3fad76)) (nicolai-nordic)
+- Remove `_` prefix as it isn't allowed by npm config ([#153](https://github.com/prebuild/prebuild-install/issues/153)) ([`a964e5b`](https://github.com/prebuild/prebuild-install/commit/a964e5b)) (Tom Boothman)
+- Make `rc.path` absolute ([#158](https://github.com/prebuild/prebuild-install/issues/158)) ([`57bcc06`](https://github.com/prebuild/prebuild-install/commit/57bcc06)) (George Waters).
+
+## [6.1.3] - 2021-06-03
+
+### Changed
+
+- Inline no longer maintained `noop-logger` ([#155](https://github.com/prebuild/prebuild-install/issues/155)) ([`e08d75a`](https://github.com/prebuild/prebuild-install/commit/e08d75a)) (Alexandru Dima)
+- Point users towards `prebuildify` in README ([#150](https://github.com/prebuild/prebuild-install/issues/150)) ([`5ee1a2f`](https://github.com/prebuild/prebuild-install/commit/5ee1a2f)) (Vincent Weevers)
+
+## [6.1.2] - 2021-04-24
+
+### Fixed
+
+- Support URL-safe strings in scoped packages ([#148](https://github.com/prebuild/prebuild-install/issues/148)) ([`db36c7a`](https://github.com/prebuild/prebuild-install/commit/db36c7a)) (Marco)
+
+## [6.1.1] - 2021-04-04
+
+### Fixed
+
+- Support `force` & `buildFromSource` options in yarn ([#140](https://github.com/prebuild/prebuild-install/issues/140)) ([`8cb1ced`](https://github.com/prebuild/prebuild-install/commit/8cb1ced)) (João Moreno)
+- Bump `node-abi` to prevent dedupe (closes [#135](https://github.com/prebuild/prebuild-install/issues/135)) ([`2950fb2`](https://github.com/prebuild/prebuild-install/commit/2950fb2)) (Vincent Weevers)
+
+## [6.1.0] - 2021-04-03
+
+### Added
+
+- Restore local prebuilds feature ([#137](https://github.com/prebuild/prebuild-install/issues/137)) ([`dc4e5ea`](https://github.com/prebuild/prebuild-install/commit/dc4e5ea)) (Wes Roberts). Previously removed in [#81](https://github.com/prebuild/prebuild-install/issues/81) / [`a069253`](https://github.com/prebuild/prebuild-install/commit/a06925378d38ca821bfa93aa4c1fdedc253b2420).
+
+## [6.0.1] - 2021-02-14
+
+### Fixed
+
+- Fixes empty `--tag-prefix` ([#143](https://github.com/prebuild/prebuild-install/issues/143)) ([**@mathiask88**](https://github.com/mathiask88))
+
+## [6.0.0] - 2020-10-23
+
+### Changed
+
+- **Breaking:** don't skip downloads in standalone mode ([`b6f3b36`](https://github.com/prebuild/prebuild-install/commit/b6f3b36)) ([**@vweevers**](https://github.com/vweevers))
+
+### Added
+
+- Document cross platform options ([`e5c9a5a`](https://github.com/prebuild/prebuild-install/commit/e5c9a5a)) ([**@fishbone1**](https://github.com/fishbone1))
+
+### Removed
+
+- **Breaking:** remove `--compile` and `--prebuild` options ([`94f2492`](https://github.com/prebuild/prebuild-install/commit/94f2492)) ([**@vweevers**](https://github.com/vweevers))
+
+### Fixed
+
+- Support npm 7 ([`8acccac`](https://github.com/prebuild/prebuild-install/commit/8acccac), [`08eaf6d`](https://github.com/prebuild/prebuild-install/commit/08eaf6d), [`22175b8`](https://github.com/prebuild/prebuild-install/commit/22175b8)) ([**@vweevers**](https://github.com/vweevers))
+
+## [5.3.6] - 2020-10-20
+
+### Changed
+
+- Replace `mkdirp` dependency with `mkdirp-classic` ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+[7.1.3]: https://github.com/prebuild/prebuild-install/releases/tag/v7.1.3
+
+[7.1.2]: https://github.com/prebuild/prebuild-install/releases/tag/v7.1.2
+
+[7.1.1]: https://github.com/prebuild/prebuild-install/releases/tag/v7.1.1
+
+[7.1.0]: https://github.com/prebuild/prebuild-install/releases/tag/v7.1.0
+
+[7.0.1]: https://github.com/prebuild/prebuild-install/releases/tag/v7.0.1
+
+[7.0.0]: https://github.com/prebuild/prebuild-install/releases/tag/v7.0.0
+
+[6.1.4]: https://github.com/prebuild/prebuild-install/releases/tag/v6.1.4
+
+[6.1.3]: https://github.com/prebuild/prebuild-install/releases/tag/v6.1.3
+
+[6.1.2]: https://github.com/prebuild/prebuild-install/releases/tag/v6.1.2
+
+[6.1.1]: https://github.com/prebuild/prebuild-install/releases/tag/v6.1.1
+
+[6.1.0]: https://github.com/prebuild/prebuild-install/releases/tag/v6.1.0
+
+[6.0.1]: https://github.com/prebuild/prebuild-install/releases/tag/v6.0.1
+
+[6.0.0]: https://github.com/prebuild/prebuild-install/releases/tag/v6.0.0
+
+[5.3.6]: https://github.com/prebuild/prebuild-install/releases/tag/v5.3.6
diff --git a/server/node_modules/prebuild-install/CONTRIBUTING.md b/server/node_modules/prebuild-install/CONTRIBUTING.md
new file mode 100644
index 0000000..07860da
--- /dev/null
+++ b/server/node_modules/prebuild-install/CONTRIBUTING.md
@@ -0,0 +1,6 @@
+# Contributing to prebuild
+
+- no commits direct to master
+- all commits as pull requests (one or several per PR)
+- each commit solves one identifiable problem
+- never merge one's own PRs, another contributor does this
diff --git a/server/node_modules/prebuild-install/LICENSE b/server/node_modules/prebuild-install/LICENSE
new file mode 100644
index 0000000..66a4d2a
--- /dev/null
+++ b/server/node_modules/prebuild-install/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 Mathias Buus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/prebuild-install/README.md b/server/node_modules/prebuild-install/README.md
new file mode 100644
index 0000000..d5aafa9
--- /dev/null
+++ b/server/node_modules/prebuild-install/README.md
@@ -0,0 +1,163 @@
+# prebuild-install
+
+> **A command line tool to easily install prebuilt binaries for multiple versions of Node.js & Electron on a specific platform.**
+> By default it downloads prebuilt binaries from a GitHub release.
+
+[![npm](https://img.shields.io/npm/v/prebuild-install.svg)](https://www.npmjs.com/package/prebuild-install)
+![Node version](https://img.shields.io/node/v/prebuild-install.svg)
+[![Test](https://img.shields.io/github/workflow/status/prebuild/prebuild-install/Test?label=test)](https://github.com/prebuild/prebuild-install/actions/workflows/test.yml)
+[![Standard](https://img.shields.io/badge/standard-informational?logo=javascript\&logoColor=fff)](https://standardjs.com)
+[![Common Changelog](https://common-changelog.org/badge.svg)](https://common-changelog.org)
+
+## Note
+
+**Instead of [`prebuild`](https://github.com/prebuild/prebuild) paired with [`prebuild-install`](https://github.com/prebuild/prebuild-install), we recommend [`prebuildify`](https://github.com/prebuild/prebuildify) paired with [`node-gyp-build`](https://github.com/prebuild/node-gyp-build).**
+
+With `prebuildify`, all prebuilt binaries are shipped inside the package that is published to npm, which means there's no need for a separate download step like you find in `prebuild`. The irony of this approach is that it is faster to download all prebuilt binaries for every platform when they are bundled than it is to download a single prebuilt binary as an install script.
+
+Upsides:
+
+1. No extra download step, making it more reliable and faster to install.
+2. Supports changing runtime versions locally and using the same install between Node.js and Electron. Reinstalling or rebuilding is not necessary, as all prebuilt binaries are in the npm tarball and the correct one is simply picked on runtime.
+3. The `node-gyp-build` runtime dependency is dependency-free and will remain so out of principle, because introducing dependencies would negate the shorter install time.
+4. Prebuilt binaries work even if npm install scripts are disabled.
+5. The npm package checksum covers prebuilt binaries too.
+
+Downsides:
+
+1. The installed npm package is larger on disk. Using [Node-API](https://nodejs.org/api/n-api.html) alleviates this because Node-API binaries are runtime-agnostic and forward-compatible.
+2. Publishing is mildly more complicated, because `npm publish` must be done after compiling and fetching prebuilt binaries (typically in CI).
+
+## Usage
+
+Use [`prebuild`](https://github.com/prebuild/prebuild) to create and upload prebuilt binaries. Then change your package.json install script to:
+
+```json
+{
+  "scripts": {
+    "install": "prebuild-install || node-gyp rebuild"
+  }
+}
+```
+
+When a consumer then installs your package with npm thus triggering the above install script, `prebuild-install` will download a suitable prebuilt binary, or exit with a non-zero exit code if there is none, which triggers `node-gyp rebuild` in order to build from source.
+
+Options (see below) can be passed to `prebuild-install` like so:
+
+```json
+{
+  "scripts": {
+    "install": "prebuild-install -r napi || node-gyp rebuild"
+  }
+}
+```
+
+### Help
+
+```
+prebuild-install [options]
+
+  --download    -d  [url]       (download prebuilds, no url means github)
+  --target      -t  version     (version to install for)
+  --runtime     -r  runtime     (Node runtime [node, napi or electron] to build or install for, default is node)
+  --path        -p  path        (make a prebuild-install here)
+  --token       -T  gh-token    (github token for private repos)
+  --arch            arch        (target CPU architecture, see Node OS module docs, default is current arch)
+  --platform        platform    (target platform, see Node OS module docs, default is current platform)
+  --tag-prefix <prefix>         (github tag prefix, default is "v")
+  --build-from-source           (skip prebuild download)
+  --verbose                     (log verbosely)
+  --libc                        (use provided libc rather than system default)
+  --debug                       (set Debug or Release configuration)
+  --version                     (print prebuild-install version and exit)
+```
+
+When `prebuild-install` is run via an `npm` script, options `--build-from-source`, `--debug`, `--download`, `--target`, `--runtime`, `--arch` `--platform` and `--libc` may be passed through via arguments given to the `npm` command.
+
+Alternatively you can set environment variables `npm_config_build_from_source=true`, `npm_config_platform`, `npm_config_arch`, `npm_config_target` `npm_config_runtime` and `npm_config_libc`.
+
+### Libc
+
+On non-glibc Linux platforms, the Libc name is appended to platform name. For example, musl-based environments are called `linuxmusl`. If `--libc=glibc` is passed as option, glibc is discarded and platform is called as just `linux`. This can be used for example to build cross-platform packages on Alpine Linux.
+
+### Private Repositories
+
+`prebuild-install` supports downloading prebuilds from private GitHub repositories using the `-T <github-token>`:
+
+```
+$ prebuild-install -T <github-token>
+```
+
+If you don't want to use the token on cli you can put it in `~/.prebuild-installrc`:
+
+```
+token=<github-token>
+```
+
+Alternatively you can specify it in the `prebuild-install_token` environment variable.
+
+Note that using a GitHub token uses the API to resolve the correct release meaning that you are subject to the ([GitHub Rate Limit](https://developer.github.com/v3/rate_limit/)).
+
+### Create GitHub Token
+
+To create a token:
+
+- Go to [this page](https://github.com/settings/tokens)
+- Click the `Generate new token` button
+- Give the token a name and click the `Generate token` button, see below
+
+![prebuild-token](https://cloud.githubusercontent.com/assets/13285808/20844584/d0b85268-b8c0-11e6-8b08-2b19522165a9.png)
+
+The default scopes should be fine.
+
+### Custom binaries
+
+The end user can override binary download location through environment variables in their .npmrc file.
+The variable needs to meet the mask `% your package name %_binary_host` or `% your package name %_binary_host_mirror`. For example:
+
+```
+leveldown_binary_host=http://overriden-host.com/overriden-path
+```
+
+Note that the package version subpath and file name will still be appended.
+So if you are installing `leveldown@1.2.3` the resulting url will be:
+
+```
+http://overriden-host.com/overriden-path/v1.2.3/leveldown-v1.2.3-node-v57-win32-x64.tar.gz
+```
+
+#### Local prebuilds
+
+If you want to use prebuilds from your local filesystem, you can use the `% your package name %_local_prebuilds` .npmrc variable to set a path to the folder containing prebuilds. For example:
+
+```
+leveldown_local_prebuilds=/path/to/prebuilds
+```
+
+This option will look directly in that folder for bundles created with `prebuild`, for example:
+
+```
+/path/to/prebuilds/leveldown-v1.2.3-node-v57-win32-x64.tar.gz
+```
+
+Non-absolute paths resolve relative to the directory of the package invoking prebuild-install, e.g. for nested dependencies.
+
+### Cache
+
+All prebuilt binaries are cached to minimize traffic. So first `prebuild-install` picks binaries from the cache and if no binary could be found, it will be downloaded. Depending on the environment, the cache folder is determined in the following order:
+
+- `${npm_config_cache}/_prebuilds`
+- `${APP_DATA}/npm-cache/_prebuilds`
+- `${HOME}/.npm/_prebuilds`
+
+## Install
+
+With [npm](https://npmjs.org) do:
+
+```
+npm install prebuild-install
+```
+
+## License
+
+[MIT](./LICENSE)
diff --git a/server/node_modules/prebuild-install/asset.js b/server/node_modules/prebuild-install/asset.js
new file mode 100644
index 0000000..7a58e8b
--- /dev/null
+++ b/server/node_modules/prebuild-install/asset.js
@@ -0,0 +1,44 @@
+const get = require('simple-get')
+const util = require('./util')
+const proxy = require('./proxy')
+
+function findAssetId (opts, cb) {
+  const downloadUrl = util.getDownloadUrl(opts)
+  const apiUrl = util.getApiUrl(opts)
+  const log = opts.log || util.noopLogger
+
+  log.http('request', 'GET ' + apiUrl)
+  const reqOpts = proxy({
+    url: apiUrl,
+    json: true,
+    headers: {
+      'User-Agent': 'simple-get',
+      Authorization: 'token ' + opts.token
+    }
+  }, opts)
+
+  const req = get.concat(reqOpts, function (err, res, data) {
+    if (err) return cb(err)
+    log.http(res.statusCode, apiUrl)
+    if (res.statusCode !== 200) return cb(err)
+
+    // Find asset id in release
+    for (const release of data) {
+      if (release.tag_name === opts['tag-prefix'] + opts.pkg.version) {
+        for (const asset of release.assets) {
+          if (asset.browser_download_url === downloadUrl) {
+            return cb(null, asset.id)
+          }
+        }
+      }
+    }
+
+    cb(new Error('Could not find GitHub release for version'))
+  })
+
+  req.setTimeout(30 * 1000, function () {
+    req.abort()
+  })
+}
+
+module.exports = findAssetId
diff --git a/server/node_modules/prebuild-install/bin.js b/server/node_modules/prebuild-install/bin.js
new file mode 100755
index 0000000..e5260cc
--- /dev/null
+++ b/server/node_modules/prebuild-install/bin.js
@@ -0,0 +1,78 @@
+#!/usr/bin/env node
+
+const path = require('path')
+const fs = require('fs')
+const napi = require('napi-build-utils')
+
+const pkg = require(path.resolve('package.json'))
+const rc = require('./rc')(pkg)
+const log = require('./log')(rc, process.env)
+const download = require('./download')
+const asset = require('./asset')
+const util = require('./util')
+
+const prebuildClientVersion = require('./package.json').version
+if (rc.version) {
+  console.log(prebuildClientVersion)
+  process.exit(0)
+}
+
+if (rc.path) process.chdir(rc.path)
+
+if (rc.runtime === 'electron' && rc.target[0] === '4' && rc.abi === '64') {
+  log.error(`Electron version ${rc.target} found - skipping prebuild-install work due to known ABI issue`)
+  log.error('More information about this issue can be found at https://github.com/lgeiger/node-abi/issues/54')
+  process.exit(1)
+}
+
+if (!fs.existsSync('package.json')) {
+  log.error('setup', 'No package.json found. Aborting...')
+  process.exit(1)
+}
+
+if (rc.help) {
+  console.error(fs.readFileSync(path.join(__dirname, 'help.txt'), 'utf-8'))
+  process.exit(0)
+}
+
+log.info('begin', 'Prebuild-install version', prebuildClientVersion)
+
+const opts = Object.assign({}, rc, { pkg: pkg, log: log })
+
+if (napi.isNapiRuntime(rc.runtime)) napi.logUnsupportedVersion(rc.target, log)
+
+const origin = util.packageOrigin(process.env, pkg)
+
+if (opts.force) {
+  log.warn('install', 'prebuilt binaries enforced with --force!')
+  log.warn('install', 'prebuilt binaries may be out of date!')
+} else if (origin && origin.length > 4 && origin.substr(0, 4) === 'git+') {
+  log.info('install', 'installing from git repository, skipping download.')
+  process.exit(1)
+} else if (opts.buildFromSource) {
+  log.info('install', '--build-from-source specified, not attempting download.')
+  process.exit(1)
+}
+
+const startDownload = function (downloadUrl) {
+  download(downloadUrl, opts, function (err) {
+    if (err) {
+      log.warn('install', err.message)
+      return process.exit(1)
+    }
+    log.info('install', 'Successfully installed prebuilt binary!')
+  })
+}
+
+if (opts.token) {
+  asset(opts, function (err, assetId) {
+    if (err) {
+      log.warn('install', err.message)
+      return process.exit(1)
+    }
+
+    startDownload(util.getAssetUrl(opts, assetId))
+  })
+} else {
+  startDownload(util.getDownloadUrl(opts))
+}
diff --git a/server/node_modules/prebuild-install/download.js b/server/node_modules/prebuild-install/download.js
new file mode 100644
index 0000000..26f04b0
--- /dev/null
+++ b/server/node_modules/prebuild-install/download.js
@@ -0,0 +1,142 @@
+const path = require('path')
+const fs = require('fs')
+const get = require('simple-get')
+const pump = require('pump')
+const tfs = require('tar-fs')
+const zlib = require('zlib')
+const util = require('./util')
+const error = require('./error')
+const proxy = require('./proxy')
+const mkdirp = require('mkdirp-classic')
+
+function downloadPrebuild (downloadUrl, opts, cb) {
+  let cachedPrebuild = util.cachedPrebuild(downloadUrl)
+  const localPrebuild = util.localPrebuild(downloadUrl, opts)
+  const tempFile = util.tempFile(cachedPrebuild)
+  const log = opts.log || util.noopLogger
+
+  if (opts.nolocal) return download()
+
+  log.info('looking for local prebuild @', localPrebuild)
+  fs.access(localPrebuild, fs.R_OK | fs.W_OK, function (err) {
+    if (err && err.code === 'ENOENT') {
+      return download()
+    }
+
+    log.info('found local prebuild')
+    cachedPrebuild = localPrebuild
+    unpack()
+  })
+
+  function download () {
+    ensureNpmCacheDir(function (err) {
+      if (err) return onerror(err)
+
+      log.info('looking for cached prebuild @', cachedPrebuild)
+      fs.access(cachedPrebuild, fs.R_OK | fs.W_OK, function (err) {
+        if (!(err && err.code === 'ENOENT')) {
+          log.info('found cached prebuild')
+          return unpack()
+        }
+
+        log.http('request', 'GET ' + downloadUrl)
+        const reqOpts = proxy({ url: downloadUrl }, opts)
+
+        if (opts.token) {
+          reqOpts.headers = {
+            'User-Agent': 'simple-get',
+            Accept: 'application/octet-stream',
+            Authorization: 'token ' + opts.token
+          }
+        }
+
+        const req = get(reqOpts, function (err, res) {
+          if (err) return onerror(err)
+          log.http(res.statusCode, downloadUrl)
+          if (res.statusCode !== 200) return onerror()
+          mkdirp(util.prebuildCache(), function () {
+            log.info('downloading to @', tempFile)
+            pump(res, fs.createWriteStream(tempFile), function (err) {
+              if (err) return onerror(err)
+              fs.rename(tempFile, cachedPrebuild, function (err) {
+                if (err) return cb(err)
+                log.info('renaming to @', cachedPrebuild)
+                unpack()
+              })
+            })
+          })
+        })
+
+        req.setTimeout(30 * 1000, function () {
+          req.abort()
+        })
+      })
+
+      function onerror (err) {
+        fs.unlink(tempFile, function () {
+          cb(err || error.noPrebuilts(opts))
+        })
+      }
+    })
+  }
+
+  function unpack () {
+    let binaryName
+
+    const updateName = opts.updateName || function (entry) {
+      if (/\.node$/i.test(entry.name)) binaryName = entry.name
+    }
+
+    log.info('unpacking @', cachedPrebuild)
+
+    const options = {
+      readable: true,
+      writable: true,
+      hardlinkAsFilesFallback: true
+    }
+    const extract = tfs.extract(opts.path, options).on('entry', updateName)
+
+    pump(fs.createReadStream(cachedPrebuild), zlib.createGunzip(), extract,
+      function (err) {
+        if (err) return cb(err)
+
+        let resolved
+        if (binaryName) {
+          try {
+            resolved = path.resolve(opts.path || '.', binaryName)
+          } catch (err) {
+            return cb(err)
+          }
+          log.info('unpack', 'resolved to ' + resolved)
+
+          if (opts.runtime === 'node' && opts.platform === process.platform && opts.abi === process.versions.modules && opts.arch === process.arch) {
+            try {
+              require(resolved)
+            } catch (err) {
+              return cb(err)
+            }
+            log.info('unpack', 'required ' + resolved + ' successfully')
+          }
+        }
+
+        cb(null, resolved)
+      })
+  }
+
+  function ensureNpmCacheDir (cb) {
+    const cacheFolder = util.npmCache()
+    fs.access(cacheFolder, fs.R_OK | fs.W_OK, function (err) {
+      if (err && err.code === 'ENOENT') {
+        return makeNpmCacheDir()
+      }
+      cb(err)
+    })
+
+    function makeNpmCacheDir () {
+      log.info('npm cache directory missing, creating it...')
+      mkdirp(cacheFolder, cb)
+    }
+  }
+}
+
+module.exports = downloadPrebuild
diff --git a/server/node_modules/prebuild-install/error.js b/server/node_modules/prebuild-install/error.js
new file mode 100644
index 0000000..c266c18
--- /dev/null
+++ b/server/node_modules/prebuild-install/error.js
@@ -0,0 +1,14 @@
+exports.noPrebuilts = function (opts) {
+  return new Error([
+    'No prebuilt binaries found',
+    '(target=' + opts.target,
+    'runtime=' + opts.runtime,
+    'arch=' + opts.arch,
+    'libc=' + opts.libc,
+    'platform=' + opts.platform + ')'
+  ].join(' '))
+}
+
+exports.invalidArchive = function () {
+  return new Error('Missing .node file in archive')
+}
diff --git a/server/node_modules/prebuild-install/help.txt b/server/node_modules/prebuild-install/help.txt
new file mode 100644
index 0000000..0dd316e
--- /dev/null
+++ b/server/node_modules/prebuild-install/help.txt
@@ -0,0 +1,16 @@
+prebuild-install [options]
+
+  --download    -d  [url]       (download prebuilds, no url means github)
+  --target      -t  version     (version to install for)
+  --runtime     -r  runtime     (Node runtime [node or electron] to build or install for, default is node)
+  --path        -p  path        (make a prebuild-install here)
+  --token       -T  gh-token    (github token for private repos)
+  --arch            arch        (target CPU architecture, see Node OS module docs, default is current arch)
+  --platform        platform    (target platform, see Node OS module docs, default is current platform)
+  --tag-prefix <prefix>         (github tag prefix, default is "v")
+  --force                       (always use prebuilt binaries when available)
+  --build-from-source           (skip prebuild download)
+  --verbose                     (log verbosely)
+  --libc                        (use provided libc rather than system default)
+  --debug                       (set Debug or Release configuration)
+  --version                     (print prebuild-install version and exit)
diff --git a/server/node_modules/prebuild-install/index.js b/server/node_modules/prebuild-install/index.js
new file mode 100644
index 0000000..b5fc28a
--- /dev/null
+++ b/server/node_modules/prebuild-install/index.js
@@ -0,0 +1 @@
+exports.download = require('./download')
diff --git a/server/node_modules/prebuild-install/log.js b/server/node_modules/prebuild-install/log.js
new file mode 100644
index 0000000..b5ecc01
--- /dev/null
+++ b/server/node_modules/prebuild-install/log.js
@@ -0,0 +1,33 @@
+const levels = {
+  silent: 0,
+  error: 1,
+  warn: 2,
+  notice: 3,
+  http: 4,
+  timing: 5,
+  info: 6,
+  verbose: 7,
+  silly: 8
+}
+
+module.exports = function (rc, env) {
+  const level = rc.verbose
+    ? 'verbose'
+    : env.npm_config_loglevel || 'notice'
+
+  const logAtLevel = function (messageLevel) {
+    return function (...args) {
+      if (levels[messageLevel] <= levels[level]) {
+        console.error(`prebuild-install ${messageLevel} ${args.join(' ')}`)
+      }
+    }
+  }
+
+  return {
+    error: logAtLevel('error'),
+    warn: logAtLevel('warn'),
+    http: logAtLevel('http'),
+    info: logAtLevel('info'),
+    level
+  }
+}
diff --git a/server/node_modules/prebuild-install/package.json b/server/node_modules/prebuild-install/package.json
new file mode 100644
index 0000000..316b8c2
--- /dev/null
+++ b/server/node_modules/prebuild-install/package.json
@@ -0,0 +1,67 @@
+{
+  "name": "prebuild-install",
+  "version": "7.1.3",
+  "description": "A command line tool to easily install prebuilt binaries for multiple version of node/iojs on a specific platform",
+  "scripts": {
+    "test": "standard && hallmark && tape test/*-test.js",
+    "hallmark": "hallmark --fix"
+  },
+  "keywords": [
+    "prebuilt",
+    "binaries",
+    "native",
+    "addon",
+    "module",
+    "c",
+    "c++",
+    "bindings",
+    "devops",
+    "napi"
+  ],
+  "dependencies": {
+    "detect-libc": "^2.0.0",
+    "expand-template": "^2.0.3",
+    "github-from-package": "0.0.0",
+    "minimist": "^1.2.3",
+    "mkdirp-classic": "^0.5.3",
+    "napi-build-utils": "^2.0.0",
+    "node-abi": "^3.3.0",
+    "pump": "^3.0.0",
+    "rc": "^1.2.7",
+    "simple-get": "^4.0.0",
+    "tar-fs": "^2.0.0",
+    "tunnel-agent": "^0.6.0"
+  },
+  "devDependencies": {
+    "a-native-module": "^1.0.0",
+    "hallmark": "^4.0.0",
+    "nock": "^10.0.6",
+    "rimraf": "^2.5.2",
+    "standard": "^16.0.4",
+    "tape": "^5.3.1",
+    "tempy": "0.2.1"
+  },
+  "bin": "./bin.js",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/prebuild/prebuild-install.git"
+  },
+  "author": "Mathias Buus (@mafintosh)",
+  "contributors": [
+    "Julian Gruber <julian@juliangruber.com> (https://github.com/juliangruber)",
+    "Brett Lawson <brett19@gmail.com> (https://github.com/brett19)",
+    "Pieter Hintjens <ph@imatix.com> (https://github.com/hintjens)",
+    "Lars-Magnus Skog <ralphtheninja@riseup.net> (https://github.com/ralphtheninja)",
+    "Jesús Leganés Combarro <piranna@gmail.com> (https://github.com/piranna)",
+    "Mathias Küsel <mathiask@hotmail.de> (https://github.com/mathiask88)",
+    "Lukas Geiger <lukas.geiger94@gmail.com> (https://github.com/lgeiger)"
+  ],
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/prebuild/prebuild-install/issues"
+  },
+  "homepage": "https://github.com/prebuild/prebuild-install",
+  "engines": {
+    "node": ">=10"
+  }
+}
\ No newline at end of file
diff --git a/server/node_modules/prebuild-install/proxy.js b/server/node_modules/prebuild-install/proxy.js
new file mode 100644
index 0000000..40d3aea
--- /dev/null
+++ b/server/node_modules/prebuild-install/proxy.js
@@ -0,0 +1,35 @@
+const url = require('url')
+const tunnel = require('tunnel-agent')
+const util = require('./util')
+
+function applyProxy (reqOpts, opts) {
+  const log = opts.log || util.noopLogger
+
+  const proxy = opts['https-proxy'] || opts.proxy
+
+  if (proxy) {
+    // eslint-disable-next-line node/no-deprecated-api
+    const parsedDownloadUrl = url.parse(reqOpts.url)
+    // eslint-disable-next-line node/no-deprecated-api
+    const parsedProxy = url.parse(proxy)
+    const uriProtocol = (parsedDownloadUrl.protocol === 'https:' ? 'https' : 'http')
+    const proxyProtocol = (parsedProxy.protocol === 'https:' ? 'Https' : 'Http')
+    const tunnelFnName = [uriProtocol, proxyProtocol].join('Over')
+    reqOpts.agent = tunnel[tunnelFnName]({
+      proxy: {
+        host: parsedProxy.hostname,
+        port: +parsedProxy.port,
+        proxyAuth: parsedProxy.auth
+      }
+    })
+    log.http('request', 'Proxy setup detected (Host: ' +
+    parsedProxy.hostname + ', Port: ' +
+      parsedProxy.port + ', Authentication: ' +
+      (parsedProxy.auth ? 'Yes' : 'No') + ')' +
+      ' Tunneling with ' + tunnelFnName)
+  }
+
+  return reqOpts
+}
+
+module.exports = applyProxy
diff --git a/server/node_modules/prebuild-install/rc.js b/server/node_modules/prebuild-install/rc.js
new file mode 100644
index 0000000..de0ea7a
--- /dev/null
+++ b/server/node_modules/prebuild-install/rc.js
@@ -0,0 +1,64 @@
+const path = require('path')
+const minimist = require('minimist')
+const getAbi = require('node-abi').getAbi
+const detectLibc = require('detect-libc')
+const napi = require('napi-build-utils')
+
+const env = process.env
+
+const libc = env.LIBC || process.env.npm_config_libc ||
+  (detectLibc.isNonGlibcLinuxSync() && detectLibc.familySync()) || ''
+
+// Get the configuration
+module.exports = function (pkg) {
+  const pkgConf = pkg.config || {}
+  const buildFromSource = env.npm_config_build_from_source
+
+  const rc = require('rc')('prebuild-install', {
+    target: pkgConf.target || env.npm_config_target || process.versions.node,
+    runtime: pkgConf.runtime || env.npm_config_runtime || 'node',
+    arch: pkgConf.arch || env.npm_config_arch || process.arch,
+    libc: libc,
+    platform: env.npm_config_platform || process.platform,
+    debug: env.npm_config_debug === 'true',
+    force: false,
+    verbose: env.npm_config_verbose === 'true',
+    buildFromSource: buildFromSource === pkg.name || buildFromSource === 'true',
+    path: '.',
+    proxy: env.npm_config_proxy || env.http_proxy || env.HTTP_PROXY,
+    'https-proxy': env.npm_config_https_proxy || env.https_proxy || env.HTTPS_PROXY,
+    'local-address': env.npm_config_local_address,
+    'local-prebuilds': 'prebuilds',
+    'tag-prefix': 'v',
+    download: env.npm_config_download
+  }, minimist(process.argv, {
+    alias: {
+      target: 't',
+      runtime: 'r',
+      help: 'h',
+      arch: 'a',
+      path: 'p',
+      version: 'v',
+      download: 'd',
+      buildFromSource: 'build-from-source',
+      token: 'T'
+    }
+  }))
+
+  rc.path = path.resolve(rc.path === true ? '.' : rc.path || '.')
+
+  if (napi.isNapiRuntime(rc.runtime) && rc.target === process.versions.node) {
+    rc.target = napi.getBestNapiBuildVersion()
+  }
+
+  rc.abi = napi.isNapiRuntime(rc.runtime) ? rc.target : getAbi(rc.target, rc.runtime)
+
+  rc.libc = rc.platform !== 'linux' || rc.libc === detectLibc.GLIBC ? '' : rc.libc
+
+  return rc
+}
+
+// Print the configuration values when executed standalone for testing purposses
+if (!module.parent) {
+  console.log(JSON.stringify(module.exports({}), null, 2))
+}
diff --git a/server/node_modules/prebuild-install/util.js b/server/node_modules/prebuild-install/util.js
new file mode 100644
index 0000000..d7cc515
--- /dev/null
+++ b/server/node_modules/prebuild-install/util.js
@@ -0,0 +1,143 @@
+const path = require('path')
+const github = require('github-from-package')
+const home = require('os').homedir
+const crypto = require('crypto')
+const expandTemplate = require('expand-template')()
+
+function getDownloadUrl (opts) {
+  const pkgName = opts.pkg.name.replace(/^@[a-zA-Z0-9_\-.~]+\//, '')
+  return expandTemplate(urlTemplate(opts), {
+    name: pkgName,
+    package_name: pkgName,
+    version: opts.pkg.version,
+    major: opts.pkg.version.split('.')[0],
+    minor: opts.pkg.version.split('.')[1],
+    patch: opts.pkg.version.split('.')[2],
+    prerelease: opts.pkg.version.split('-')[1],
+    build: opts.pkg.version.split('+')[1],
+    abi: opts.abi || process.versions.modules,
+    node_abi: process.versions.modules,
+    runtime: opts.runtime || 'node',
+    platform: opts.platform,
+    arch: opts.arch,
+    libc: opts.libc || '',
+    configuration: (opts.debug ? 'Debug' : 'Release'),
+    module_name: opts.pkg.binary && opts.pkg.binary.module_name,
+    tag_prefix: opts['tag-prefix']
+  })
+}
+
+function getApiUrl (opts) {
+  return github(opts.pkg).replace('github.com', 'api.github.com/repos') + '/releases'
+}
+
+function getAssetUrl (opts, assetId) {
+  return getApiUrl(opts) + '/assets/' + assetId
+}
+
+function urlTemplate (opts) {
+  if (typeof opts.download === 'string') {
+    return opts.download
+  }
+
+  const packageName = '{name}-v{version}-{runtime}-v{abi}-{platform}{libc}-{arch}.tar.gz'
+  const hostMirrorUrl = getHostMirrorUrl(opts)
+
+  if (hostMirrorUrl) {
+    return hostMirrorUrl + '/{tag_prefix}{version}/' + packageName
+  }
+
+  if (opts.pkg.binary && opts.pkg.binary.host) {
+    return [
+      opts.pkg.binary.host,
+      opts.pkg.binary.remote_path,
+      opts.pkg.binary.package_name || packageName
+    ].map(function (path) {
+      return trimSlashes(path)
+    }).filter(Boolean).join('/')
+  }
+
+  return github(opts.pkg) + '/releases/download/{tag_prefix}{version}/' + packageName
+}
+
+function getEnvPrefix (pkgName) {
+  return 'npm_config_' + (pkgName || '').replace(/[^a-zA-Z0-9]/g, '_').replace(/^_/, '')
+}
+
+function getHostMirrorUrl (opts) {
+  const propName = getEnvPrefix(opts.pkg.name) + '_binary_host'
+  return process.env[propName] || process.env[propName + '_mirror']
+}
+
+function trimSlashes (str) {
+  if (str) return str.replace(/^\.\/|^\/|\/$/g, '')
+}
+
+function cachedPrebuild (url) {
+  const digest = crypto.createHash('sha512').update(url).digest('hex').slice(0, 6)
+  return path.join(prebuildCache(), digest + '-' + path.basename(url).replace(/[^a-zA-Z0-9.]+/g, '-'))
+}
+
+function npmCache () {
+  const env = process.env
+  return env.npm_config_cache || (env.APPDATA ? path.join(env.APPDATA, 'npm-cache') : path.join(home(), '.npm'))
+}
+
+function prebuildCache () {
+  return path.join(npmCache(), '_prebuilds')
+}
+
+function tempFile (cached) {
+  return cached + '.' + process.pid + '-' + Math.random().toString(16).slice(2) + '.tmp'
+}
+
+function packageOrigin (env, pkg) {
+  // npm <= 6: metadata is stored on disk in node_modules
+  if (pkg._from) {
+    return pkg._from
+  }
+
+  // npm 7: metadata is exposed to environment by arborist
+  if (env.npm_package_from) {
+    // NOTE: seems undefined atm (npm 7.0.2)
+    return env.npm_package_from
+  }
+
+  if (env.npm_package_resolved) {
+    // NOTE: not sure about the difference with _from, but it's all we have
+    return env.npm_package_resolved
+  }
+}
+
+function localPrebuild (url, opts) {
+  const propName = getEnvPrefix(opts.pkg.name) + '_local_prebuilds'
+  const prefix = process.env[propName] || opts['local-prebuilds'] || 'prebuilds'
+  return path.join(prefix, path.basename(url))
+}
+
+const noopLogger = {
+  http: function () {},
+  silly: function () {},
+  debug: function () {},
+  info: function () {},
+  warn: function () {},
+  error: function () {},
+  critical: function () {},
+  alert: function () {},
+  emergency: function () {},
+  notice: function () {},
+  verbose: function () {},
+  fatal: function () {}
+}
+
+exports.getDownloadUrl = getDownloadUrl
+exports.getApiUrl = getApiUrl
+exports.getAssetUrl = getAssetUrl
+exports.urlTemplate = urlTemplate
+exports.cachedPrebuild = cachedPrebuild
+exports.localPrebuild = localPrebuild
+exports.prebuildCache = prebuildCache
+exports.npmCache = npmCache
+exports.tempFile = tempFile
+exports.packageOrigin = packageOrigin
+exports.noopLogger = noopLogger
diff --git a/server/node_modules/process-nextick-args/index.js b/server/node_modules/process-nextick-args/index.js
new file mode 100644
index 0000000..3eecf11
--- /dev/null
+++ b/server/node_modules/process-nextick-args/index.js
@@ -0,0 +1,45 @@
+'use strict';
+
+if (typeof process === 'undefined' ||
+    !process.version ||
+    process.version.indexOf('v0.') === 0 ||
+    process.version.indexOf('v1.') === 0 && process.version.indexOf('v1.8.') !== 0) {
+  module.exports = { nextTick: nextTick };
+} else {
+  module.exports = process
+}
+
+function nextTick(fn, arg1, arg2, arg3) {
+  if (typeof fn !== 'function') {
+    throw new TypeError('"callback" argument must be a function');
+  }
+  var len = arguments.length;
+  var args, i;
+  switch (len) {
+  case 0:
+  case 1:
+    return process.nextTick(fn);
+  case 2:
+    return process.nextTick(function afterTickOne() {
+      fn.call(null, arg1);
+    });
+  case 3:
+    return process.nextTick(function afterTickTwo() {
+      fn.call(null, arg1, arg2);
+    });
+  case 4:
+    return process.nextTick(function afterTickThree() {
+      fn.call(null, arg1, arg2, arg3);
+    });
+  default:
+    args = new Array(len - 1);
+    i = 0;
+    while (i < args.length) {
+      args[i++] = arguments[i];
+    }
+    return process.nextTick(function afterTick() {
+      fn.apply(null, args);
+    });
+  }
+}
+
diff --git a/server/node_modules/process-nextick-args/license.md b/server/node_modules/process-nextick-args/license.md
new file mode 100644
index 0000000..c67e353
--- /dev/null
+++ b/server/node_modules/process-nextick-args/license.md
@@ -0,0 +1,19 @@
+# Copyright (c) 2015 Calvin Metcalf
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+**THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.**
diff --git a/server/node_modules/process-nextick-args/package.json b/server/node_modules/process-nextick-args/package.json
new file mode 100644
index 0000000..6070b72
--- /dev/null
+++ b/server/node_modules/process-nextick-args/package.json
@@ -0,0 +1,25 @@
+{
+  "name": "process-nextick-args",
+  "version": "2.0.1",
+  "description": "process.nextTick but always with args",
+  "main": "index.js",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "test": "node test.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/calvinmetcalf/process-nextick-args.git"
+  },
+  "author": "",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/calvinmetcalf/process-nextick-args/issues"
+  },
+  "homepage": "https://github.com/calvinmetcalf/process-nextick-args",
+  "devDependencies": {
+    "tap": "~0.2.6"
+  }
+}
diff --git a/server/node_modules/process-nextick-args/readme.md b/server/node_modules/process-nextick-args/readme.md
new file mode 100644
index 0000000..ecb432c
--- /dev/null
+++ b/server/node_modules/process-nextick-args/readme.md
@@ -0,0 +1,18 @@
+process-nextick-args
+=====
+
+[![Build Status](https://travis-ci.org/calvinmetcalf/process-nextick-args.svg?branch=master)](https://travis-ci.org/calvinmetcalf/process-nextick-args)
+
+```bash
+npm install --save process-nextick-args
+```
+
+Always be able to pass arguments to process.nextTick, no matter the platform
+
+```js
+var pna = require('process-nextick-args');
+
+pna.nextTick(function (a, b, c) {
+  console.log(a, b, c);
+}, 'step', 3,  'profit');
+```
diff --git a/server/node_modules/promise-inflight/LICENSE b/server/node_modules/promise-inflight/LICENSE
new file mode 100644
index 0000000..83e7c4c
--- /dev/null
+++ b/server/node_modules/promise-inflight/LICENSE
@@ -0,0 +1,14 @@
+Copyright (c) 2017, Rebecca Turner <me@re-becca.org>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
diff --git a/server/node_modules/promise-inflight/README.md b/server/node_modules/promise-inflight/README.md
new file mode 100644
index 0000000..f0ae3a4
--- /dev/null
+++ b/server/node_modules/promise-inflight/README.md
@@ -0,0 +1,34 @@
+# promise-inflight
+
+One promise for multiple requests in flight to avoid async duplication
+
+## USAGE
+
+```javascript
+const inflight = require('promise-inflight')
+
+// some request that does some stuff
+function req(key) {
+  // key is any random string.  like a url or filename or whatever.
+  return inflight(key, () => {
+    // this is where you'd fetch the url or whatever
+    return Promise.delay(100)
+  })
+}
+
+// only assigns a single setTimeout
+// when it dings, all thens get called with the same result.  (There's only
+// one underlying promise.)
+req('foo').then(…)
+req('foo').then(…)
+req('foo').then(…)
+req('foo').then(…)
+```
+
+## SEE ALSO
+
+* [inflight](https://npmjs.com/package/inflight) - For the callback based function on which this is based.
+
+## STILL NEEDS
+
+Tests!
diff --git a/server/node_modules/promise-inflight/inflight.js b/server/node_modules/promise-inflight/inflight.js
new file mode 100644
index 0000000..ce054d3
--- /dev/null
+++ b/server/node_modules/promise-inflight/inflight.js
@@ -0,0 +1,36 @@
+'use strict'
+module.exports = inflight
+
+let Bluebird
+try {
+  Bluebird = require('bluebird')
+} catch (_) {
+  Bluebird = Promise
+}
+
+const active = {}
+inflight.active = active
+function inflight (unique, doFly) {
+  return Bluebird.all([unique, doFly]).then(function (args) {
+    const unique = args[0]
+    const doFly = args[1]
+    if (Array.isArray(unique)) {
+      return Bluebird.all(unique).then(function (uniqueArr) {
+        return _inflight(uniqueArr.join(''), doFly)
+      })
+    } else {
+      return _inflight(unique, doFly)
+    }
+  })
+
+  function _inflight (unique, doFly) {
+    if (!active[unique]) {
+      active[unique] = (new Bluebird(function (resolve) {
+        return resolve(doFly())
+      }))
+      active[unique].then(cleanup, cleanup)
+      function cleanup() { delete active[unique] }
+    }
+    return active[unique]
+  }
+}
diff --git a/server/node_modules/promise-inflight/package.json b/server/node_modules/promise-inflight/package.json
new file mode 100644
index 0000000..0d8930c
--- /dev/null
+++ b/server/node_modules/promise-inflight/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "promise-inflight",
+  "version": "1.0.1",
+  "description": "One promise for multiple requests in flight to avoid async duplication",
+  "main": "inflight.js",
+  "files": [
+    "inflight.js"
+  ],
+  "license": "ISC",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "Rebecca Turner <me@re-becca.org> (http://re-becca.org/)",
+  "devDependencies": {},
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/iarna/promise-inflight.git"
+  },
+  "bugs": {
+    "url": "https://github.com/iarna/promise-inflight/issues"
+  },
+  "homepage": "https://github.com/iarna/promise-inflight#readme"
+}
diff --git a/server/node_modules/promise-retry/.editorconfig b/server/node_modules/promise-retry/.editorconfig
new file mode 100644
index 0000000..8bc4f10
--- /dev/null
+++ b/server/node_modules/promise-retry/.editorconfig
@@ -0,0 +1,15 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false
+
+[package.json]
+indent_size = 2
diff --git a/server/node_modules/promise-retry/.jshintrc b/server/node_modules/promise-retry/.jshintrc
new file mode 100644
index 0000000..d867d49
--- /dev/null
+++ b/server/node_modules/promise-retry/.jshintrc
@@ -0,0 +1,64 @@
+{
+    "predef": [
+        "console",
+        "require",
+        "define",
+        "describe",
+        "it",
+        "before",
+        "beforeEach",
+        "after",
+        "afterEach",
+        "Promise"
+    ],
+
+    "node": true,
+    "devel": true,
+
+    "bitwise": true,
+    "curly": true,
+    "eqeqeq": true,
+    "forin": false,
+    "immed": true,
+    "latedef": false,
+    "newcap": true,
+    "noarg": true,
+    "noempty": false,
+    "nonew": true,
+    "plusplus": false,
+    "regexp": true,
+    "undef": true,
+    "unused": true,
+    "quotmark": "single",
+    "strict": true,
+    "trailing": true,
+
+    "asi": false,
+    "boss": false,
+    "debug": false,
+    "eqnull": true,
+    "es5": false,
+    "esnext": false,
+    "evil": false,
+    "expr": true,
+    "funcscope": false,
+    "globalstrict": false,
+    "iterator": false,
+    "lastsemic": false,
+    "laxbreak": false,
+    "laxcomma": false,
+    "loopfunc": true,
+    "multistr": false,
+    "onecase": true,
+    "regexdash": false,
+    "scripturl": false,
+    "smarttabs": false,
+    "shadow": false,
+    "sub": false,
+    "supernew": false,
+    "validthis": false,
+
+    "nomen": false,
+    "onevar": false,
+    "white": true
+}
diff --git a/server/node_modules/promise-retry/.travis.yml b/server/node_modules/promise-retry/.travis.yml
new file mode 100644
index 0000000..e2d26a9
--- /dev/null
+++ b/server/node_modules/promise-retry/.travis.yml
@@ -0,0 +1,4 @@
+language: node_js
+node_js:
+  - "10"
+  - "12"
diff --git a/server/node_modules/promise-retry/LICENSE b/server/node_modules/promise-retry/LICENSE
new file mode 100644
index 0000000..db5e914
--- /dev/null
+++ b/server/node_modules/promise-retry/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2014 IndigoUnited
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/promise-retry/README.md b/server/node_modules/promise-retry/README.md
new file mode 100644
index 0000000..587de5c
--- /dev/null
+++ b/server/node_modules/promise-retry/README.md
@@ -0,0 +1,94 @@
+# node-promise-retry
+
+[![NPM version][npm-image]][npm-url] [![Downloads][downloads-image]][npm-url] [![Build Status][travis-image]][travis-url] [![Dependency status][david-dm-image]][david-dm-url] [![Dev Dependency status][david-dm-dev-image]][david-dm-dev-url] [![Greenkeeper badge][greenkeeper-image]][greenkeeper-url]
+
+[npm-url]:https://npmjs.org/package/promise-retry
+[downloads-image]:http://img.shields.io/npm/dm/promise-retry.svg
+[npm-image]:http://img.shields.io/npm/v/promise-retry.svg
+[travis-url]:https://travis-ci.org/IndigoUnited/node-promise-retry
+[travis-image]:http://img.shields.io/travis/IndigoUnited/node-promise-retry/master.svg
+[david-dm-url]:https://david-dm.org/IndigoUnited/node-promise-retry
+[david-dm-image]:https://img.shields.io/david/IndigoUnited/node-promise-retry.svg
+[david-dm-dev-url]:https://david-dm.org/IndigoUnited/node-promise-retry?type=dev
+[david-dm-dev-image]:https://img.shields.io/david/dev/IndigoUnited/node-promise-retry.svg
+[greenkeeper-image]:https://badges.greenkeeper.io/IndigoUnited/node-promise-retry.svg
+[greenkeeper-url]:https://greenkeeper.io/
+
+Retries a function that returns a promise, leveraging the power of the [retry](https://github.com/tim-kos/node-retry) module to the promises world.
+
+There's already some modules that are able to retry functions that return promises but
+they were rather difficult to use or do not offer an easy way to do conditional retries.
+
+
+## Installation
+
+`$ npm install promise-retry`
+
+
+## Usage
+
+### promiseRetry(fn, [options])
+
+Calls `fn` until the returned promise ends up fulfilled or rejected with an error different than
+a `retry` error.   
+The `options` argument is an object which maps to the [retry](https://github.com/tim-kos/node-retry) module options:
+
+- `retries`: The maximum amount of times to retry the operation. Default is `10`.
+- `factor`: The exponential factor to use. Default is `2`.
+- `minTimeout`: The number of milliseconds before starting the first retry. Default is `1000`.
+- `maxTimeout`: The maximum number of milliseconds between two retries. Default is `Infinity`.
+- `randomize`: Randomizes the timeouts by multiplying with a factor between `1` to `2`. Default is `false`.
+
+
+The `fn` function will receive a `retry` function as its first argument that should be called with an error whenever you want to retry `fn`. The `retry` function will always throw an error.   
+If there are retries left, it will throw a special `retry` error that will be handled internally to call `fn` again.
+If there are no retries left, it will throw the actual error passed to it.
+
+If you prefer, you can pass the options first using the alternative function signature `promiseRetry([options], fn)`.
+
+## Example
+```js
+var promiseRetry = require('promise-retry');
+
+// Simple example
+promiseRetry(function (retry, number) {
+    console.log('attempt number', number);
+
+    return doSomething()
+    .catch(retry);
+})
+.then(function (value) {
+    // ..
+}, function (err) {
+    // ..
+});
+
+// Conditional example
+promiseRetry(function (retry, number) {
+    console.log('attempt number', number);
+
+    return doSomething()
+    .catch(function (err) {
+        if (err.code === 'ETIMEDOUT') {
+            retry(err);
+        }
+
+        throw err;
+    });
+})
+.then(function (value) {
+    // ..
+}, function (err) {
+    // ..
+});
+```
+
+
+## Tests
+
+`$ npm test`
+
+
+## License
+
+Released under the [MIT License](http://www.opensource.org/licenses/mit-license.php).
diff --git a/server/node_modules/promise-retry/index.js b/server/node_modules/promise-retry/index.js
new file mode 100644
index 0000000..5df48ae
--- /dev/null
+++ b/server/node_modules/promise-retry/index.js
@@ -0,0 +1,52 @@
+'use strict';
+
+var errcode = require('err-code');
+var retry = require('retry');
+
+var hasOwn = Object.prototype.hasOwnProperty;
+
+function isRetryError(err) {
+    return err && err.code === 'EPROMISERETRY' && hasOwn.call(err, 'retried');
+}
+
+function promiseRetry(fn, options) {
+    var temp;
+    var operation;
+
+    if (typeof fn === 'object' && typeof options === 'function') {
+        // Swap options and fn when using alternate signature (options, fn)
+        temp = options;
+        options = fn;
+        fn = temp;
+    }
+
+    operation = retry.operation(options);
+
+    return new Promise(function (resolve, reject) {
+        operation.attempt(function (number) {
+            Promise.resolve()
+            .then(function () {
+                return fn(function (err) {
+                    if (isRetryError(err)) {
+                        err = err.retried;
+                    }
+
+                    throw errcode(new Error('Retrying'), 'EPROMISERETRY', { retried: err });
+                }, number);
+            })
+            .then(resolve, function (err) {
+                if (isRetryError(err)) {
+                    err = err.retried;
+
+                    if (operation.retry(err || new Error())) {
+                        return;
+                    }
+                }
+
+                reject(err);
+            });
+        });
+    });
+}
+
+module.exports = promiseRetry;
diff --git a/server/node_modules/promise-retry/package.json b/server/node_modules/promise-retry/package.json
new file mode 100644
index 0000000..6842de8
--- /dev/null
+++ b/server/node_modules/promise-retry/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "promise-retry",
+  "version": "2.0.1",
+  "description": "Retries a function that returns a promise, leveraging the power of the retry module.",
+  "main": "index.js",
+  "scripts": {
+    "test": "mocha --bail -t 10000"
+  },
+  "bugs": {
+    "url": "https://github.com/IndigoUnited/node-promise-retry/issues/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/IndigoUnited/node-promise-retry.git"
+  },
+  "keywords": [
+    "retry",
+    "promise",
+    "backoff",
+    "repeat",
+    "replay"
+  ],
+  "author": "IndigoUnited <hello@indigounited.com> (http://indigounited.com)",
+  "license": "MIT",
+  "devDependencies": {
+    "expect.js": "^0.3.1",
+    "mocha": "^8.0.1",
+    "sleep-promise": "^8.0.1"
+  },
+  "dependencies": {
+    "err-code": "^2.0.2",
+    "retry": "^0.12.0"
+  },
+  "engines": {
+    "node": ">=10"
+  }
+}
diff --git a/server/node_modules/promise-retry/test/test.js b/server/node_modules/promise-retry/test/test.js
new file mode 100644
index 0000000..466b099
--- /dev/null
+++ b/server/node_modules/promise-retry/test/test.js
@@ -0,0 +1,263 @@
+'use strict';
+
+var expect = require('expect.js');
+var promiseRetry = require('../');
+var promiseDelay = require('sleep-promise');
+
+describe('promise-retry', function () {
+    it('should call fn again if retry was called', function () {
+        var count = 0;
+
+        return promiseRetry(function (retry) {
+            count += 1;
+
+            return promiseDelay(10)
+            .then(function () {
+                if (count <= 2) {
+                    retry(new Error('foo'));
+                }
+
+                return 'final';
+            });
+        }, { factor: 1 })
+        .then(function (value) {
+            expect(value).to.be('final');
+            expect(count).to.be(3);
+        }, function () {
+            throw new Error('should not fail');
+        });
+    });
+
+    it('should call fn with the attempt number', function () {
+        var count = 0;
+
+        return promiseRetry(function (retry, number) {
+            count += 1;
+            expect(count).to.equal(number);
+
+            return promiseDelay(10)
+            .then(function () {
+                if (count <= 2) {
+                    retry(new Error('foo'));
+                }
+
+                return 'final';
+            });
+        }, { factor: 1 })
+        .then(function (value) {
+            expect(value).to.be('final');
+            expect(count).to.be(3);
+        }, function () {
+            throw new Error('should not fail');
+        });
+    });
+
+    it('should not retry on fulfillment if retry was not called', function () {
+        var count = 0;
+
+        return promiseRetry(function () {
+            count += 1;
+
+            return promiseDelay(10)
+            .then(function () {
+                return 'final';
+            });
+        })
+        .then(function (value) {
+            expect(value).to.be('final');
+            expect(count).to.be(1);
+        }, function () {
+            throw new Error('should not fail');
+        });
+    });
+
+    it('should not retry on rejection if retry was not called', function () {
+        var count = 0;
+
+        return promiseRetry(function () {
+            count += 1;
+
+            return promiseDelay(10)
+            .then(function () {
+                throw new Error('foo');
+            });
+        })
+        .then(function () {
+            throw new Error('should not succeed');
+        }, function (err) {
+            expect(err.message).to.be('foo');
+            expect(count).to.be(1);
+        });
+    });
+
+    it('should not retry on rejection if nr of retries is 0', function () {
+        var count = 0;
+
+        return promiseRetry(function (retry) {
+            count += 1;
+
+            return promiseDelay(10)
+            .then(function () {
+                throw new Error('foo');
+            })
+            .catch(retry);
+        }, { retries : 0 })
+        .then(function () {
+            throw new Error('should not succeed');
+        }, function (err) {
+            expect(err.message).to.be('foo');
+            expect(count).to.be(1);
+        });
+    });
+
+    it('should reject the promise if the retries were exceeded', function () {
+        var count = 0;
+
+        return promiseRetry(function (retry) {
+            count += 1;
+
+            return promiseDelay(10)
+            .then(function () {
+                throw new Error('foo');
+            })
+            .catch(retry);
+        }, { retries: 2, factor: 1 })
+        .then(function () {
+            throw new Error('should not succeed');
+        }, function (err) {
+            expect(err.message).to.be('foo');
+            expect(count).to.be(3);
+        });
+    });
+
+    it('should pass options to the underlying retry module', function () {
+        var count = 0;
+
+        return promiseRetry(function (retry) {
+            return promiseDelay(10)
+            .then(function () {
+                if (count < 2) {
+                    count += 1;
+                    retry(new Error('foo'));
+                }
+
+                return 'final';
+            });
+        }, { retries: 1, factor: 1 })
+        .then(function () {
+            throw new Error('should not succeed');
+        }, function (err) {
+            expect(err.message).to.be('foo');
+        });
+    });
+
+    it('should convert direct fulfillments into promises', function () {
+        return promiseRetry(function () {
+            return 'final';
+        }, { factor: 1 })
+        .then(function (value) {
+            expect(value).to.be('final');
+        }, function () {
+            throw new Error('should not fail');
+        });
+    });
+
+    it('should convert direct rejections into promises', function () {
+        promiseRetry(function () {
+            throw new Error('foo');
+        }, { retries: 1, factor: 1 })
+        .then(function () {
+            throw new Error('should not succeed');
+        }, function (err) {
+            expect(err.message).to.be('foo');
+        });
+    });
+
+    it('should not crash on undefined rejections', function () {
+        return promiseRetry(function () {
+            throw undefined;
+        }, { retries: 1, factor: 1 })
+        .then(function () {
+            throw new Error('should not succeed');
+        }, function (err) {
+            expect(err).to.be(undefined);
+        })
+        .then(function () {
+            return promiseRetry(function (retry) {
+                retry();
+            }, { retries: 1, factor: 1 });
+        })
+        .then(function () {
+            throw new Error('should not succeed');
+        }, function (err) {
+            expect(err).to.be(undefined);
+        });
+    });
+
+    it('should retry if retry() was called with undefined', function () {
+        var count = 0;
+
+        return promiseRetry(function (retry) {
+            count += 1;
+
+            return promiseDelay(10)
+            .then(function () {
+                if (count <= 2) {
+                    retry();
+                }
+
+                return 'final';
+            });
+        }, { factor: 1 })
+        .then(function (value) {
+            expect(value).to.be('final');
+            expect(count).to.be(3);
+        }, function () {
+            throw new Error('should not fail');
+        });
+    });
+
+    it('should work with several retries in the same chain', function () {
+        var count = 0;
+
+        return promiseRetry(function (retry) {
+            count += 1;
+
+            return promiseDelay(10)
+            .then(function () {
+                retry(new Error('foo'));
+            })
+            .catch(function (err) {
+                retry(err);
+            });
+        }, { retries: 1, factor: 1 })
+        .then(function () {
+            throw new Error('should not succeed');
+        }, function (err) {
+            expect(err.message).to.be('foo');
+            expect(count).to.be(2);
+        });
+    });
+
+    it('should allow options to be passed first', function () {
+        var count = 0;
+
+        return promiseRetry({ factor: 1 }, function (retry) {
+            count += 1;
+
+            return promiseDelay(10)
+                .then(function () {
+                    if (count <= 2) {
+                        retry(new Error('foo'));
+                    }
+
+                    return 'final';
+                });
+        }).then(function (value) {
+            expect(value).to.be('final');
+            expect(count).to.be(3);
+        }, function () {
+            throw new Error('should not fail');
+        });
+    });
+});
diff --git a/server/node_modules/proxy-addr/HISTORY.md b/server/node_modules/proxy-addr/HISTORY.md
new file mode 100644
index 0000000..8480242
--- /dev/null
+++ b/server/node_modules/proxy-addr/HISTORY.md
@@ -0,0 +1,161 @@
+2.0.7 / 2021-05-31
+==================
+
+  * deps: forwarded@0.2.0
+    - Use `req.socket` over deprecated `req.connection`
+
+2.0.6 / 2020-02-24
+==================
+
+  * deps: ipaddr.js@1.9.1
+
+2.0.5 / 2019-04-16
+==================
+
+  * deps: ipaddr.js@1.9.0
+
+2.0.4 / 2018-07-26
+==================
+
+  * deps: ipaddr.js@1.8.0
+
+2.0.3 / 2018-02-19
+==================
+
+  * deps: ipaddr.js@1.6.0
+
+2.0.2 / 2017-09-24
+==================
+
+  * deps: forwarded@~0.1.2
+    - perf: improve header parsing
+    - perf: reduce overhead when no `X-Forwarded-For` header
+
+2.0.1 / 2017-09-10
+==================
+
+  * deps: forwarded@~0.1.1
+    - Fix trimming leading / trailing OWS
+    - perf: hoist regular expression
+  * deps: ipaddr.js@1.5.2
+
+2.0.0 / 2017-08-08
+==================
+
+  * Drop support for Node.js below 0.10
+
+1.1.5 / 2017-07-25
+==================
+
+  * Fix array argument being altered
+  * deps: ipaddr.js@1.4.0
+
+1.1.4 / 2017-03-24
+==================
+
+  * deps: ipaddr.js@1.3.0
+
+1.1.3 / 2017-01-14
+==================
+
+  * deps: ipaddr.js@1.2.0
+
+1.1.2 / 2016-05-29
+==================
+
+  * deps: ipaddr.js@1.1.1
+    - Fix IPv6-mapped IPv4 validation edge cases
+
+1.1.1 / 2016-05-03
+==================
+
+  * Fix regression matching mixed versions against multiple subnets
+
+1.1.0 / 2016-05-01
+==================
+
+  * Fix accepting various invalid netmasks
+    - IPv4 netmasks must be contingous
+    - IPv6 addresses cannot be used as a netmask
+  * deps: ipaddr.js@1.1.0
+
+1.0.10 / 2015-12-09
+===================
+
+  * deps: ipaddr.js@1.0.5
+    - Fix regression in `isValid` with non-string arguments
+
+1.0.9 / 2015-12-01
+==================
+
+  * deps: ipaddr.js@1.0.4
+    - Fix accepting some invalid IPv6 addresses
+    - Reject CIDRs with negative or overlong masks
+  * perf: enable strict mode
+
+1.0.8 / 2015-05-10
+==================
+
+  * deps: ipaddr.js@1.0.1
+
+1.0.7 / 2015-03-16
+==================
+
+  * deps: ipaddr.js@0.1.9
+    - Fix OOM on certain inputs to `isValid`
+
+1.0.6 / 2015-02-01
+==================
+
+  * deps: ipaddr.js@0.1.8
+
+1.0.5 / 2015-01-08
+==================
+
+  * deps: ipaddr.js@0.1.6
+
+1.0.4 / 2014-11-23
+==================
+
+  * deps: ipaddr.js@0.1.5
+    - Fix edge cases with `isValid`
+
+1.0.3 / 2014-09-21
+==================
+
+  * Use `forwarded` npm module
+
+1.0.2 / 2014-09-18
+==================
+
+  * Fix a global leak when multiple subnets are trusted
+  * Support Node.js 0.6
+  * deps: ipaddr.js@0.1.3
+
+1.0.1 / 2014-06-03
+==================
+
+  * Fix links in npm package
+
+1.0.0 / 2014-05-08
+==================
+
+  * Add `trust` argument to determine proxy trust on
+    * Accepts custom function
+    * Accepts IPv4/IPv6 address(es)
+    * Accepts subnets
+    * Accepts pre-defined names
+  * Add optional `trust` argument to `proxyaddr.all` to
+    stop at first untrusted
+  * Add `proxyaddr.compile` to pre-compile `trust` function
+    to make subsequent calls faster
+
+0.0.1 / 2014-05-04
+==================
+
+  * Fix bad npm publish
+
+0.0.0 / 2014-05-04
+==================
+
+  * Initial release
diff --git a/server/node_modules/proxy-addr/LICENSE b/server/node_modules/proxy-addr/LICENSE
new file mode 100644
index 0000000..cab251c
--- /dev/null
+++ b/server/node_modules/proxy-addr/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2014-2016 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/proxy-addr/README.md b/server/node_modules/proxy-addr/README.md
new file mode 100644
index 0000000..69c0b63
--- /dev/null
+++ b/server/node_modules/proxy-addr/README.md
@@ -0,0 +1,139 @@
+# proxy-addr
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][ci-image]][ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Determine address of proxied request
+
+## Install
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install proxy-addr
+```
+
+## API
+
+```js
+var proxyaddr = require('proxy-addr')
+```
+
+### proxyaddr(req, trust)
+
+Return the address of the request, using the given `trust` parameter.
+
+The `trust` argument is a function that returns `true` if you trust
+the address, `false` if you don't. The closest untrusted address is
+returned.
+
+```js
+proxyaddr(req, function (addr) { return addr === '127.0.0.1' })
+proxyaddr(req, function (addr, i) { return i < 1 })
+```
+
+The `trust` arugment may also be a single IP address string or an
+array of trusted addresses, as plain IP addresses, CIDR-formatted
+strings, or IP/netmask strings.
+
+```js
+proxyaddr(req, '127.0.0.1')
+proxyaddr(req, ['127.0.0.0/8', '10.0.0.0/8'])
+proxyaddr(req, ['127.0.0.0/255.0.0.0', '192.168.0.0/255.255.0.0'])
+```
+
+This module also supports IPv6. Your IPv6 addresses will be normalized
+automatically (i.e. `fe80::00ed:1` equals `fe80:0:0:0:0:0:ed:1`).
+
+```js
+proxyaddr(req, '::1')
+proxyaddr(req, ['::1/128', 'fe80::/10'])
+```
+
+This module will automatically work with IPv4-mapped IPv6 addresses
+as well to support node.js in IPv6-only mode. This means that you do
+not have to specify both `::ffff:a00:1` and `10.0.0.1`.
+
+As a convenience, this module also takes certain pre-defined names
+in addition to IP addresses, which expand into IP addresses:
+
+```js
+proxyaddr(req, 'loopback')
+proxyaddr(req, ['loopback', 'fc00:ac:1ab5:fff::1/64'])
+```
+
+  * `loopback`: IPv4 and IPv6 loopback addresses (like `::1` and
+    `127.0.0.1`).
+  * `linklocal`: IPv4 and IPv6 link-local addresses (like
+    `fe80::1:1:1:1` and `169.254.0.1`).
+  * `uniquelocal`: IPv4 private addresses and IPv6 unique-local
+    addresses (like `fc00:ac:1ab5:fff::1` and `192.168.0.1`).
+
+When `trust` is specified as a function, it will be called for each
+address to determine if it is a trusted address. The function is
+given two arguments: `addr` and `i`, where `addr` is a string of
+the address to check and `i` is a number that represents the distance
+from the socket address.
+
+### proxyaddr.all(req, [trust])
+
+Return all the addresses of the request, optionally stopping at the
+first untrusted. This array is ordered from closest to furthest
+(i.e. `arr[0] === req.connection.remoteAddress`).
+
+```js
+proxyaddr.all(req)
+```
+
+The optional `trust` argument takes the same arguments as `trust`
+does in `proxyaddr(req, trust)`.
+
+```js
+proxyaddr.all(req, 'loopback')
+```
+
+### proxyaddr.compile(val)
+
+Compiles argument `val` into a `trust` function. This function takes
+the same arguments as `trust` does in `proxyaddr(req, trust)` and
+returns a function suitable for `proxyaddr(req, trust)`.
+
+```js
+var trust = proxyaddr.compile('loopback')
+var addr = proxyaddr(req, trust)
+```
+
+This function is meant to be optimized for use against every request.
+It is recommend to compile a trust function up-front for the trusted
+configuration and pass that to `proxyaddr(req, trust)` for each request.
+
+## Testing
+
+```sh
+$ npm test
+```
+
+## Benchmarks
+
+```sh
+$ npm run-script bench
+```
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/jshttp/proxy-addr/master?label=ci
+[ci-url]: https://github.com/jshttp/proxy-addr/actions?query=workflow%3Aci
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/proxy-addr/master
+[coveralls-url]: https://coveralls.io/r/jshttp/proxy-addr?branch=master
+[node-image]: https://badgen.net/npm/node/proxy-addr
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/proxy-addr
+[npm-url]: https://npmjs.org/package/proxy-addr
+[npm-version-image]: https://badgen.net/npm/v/proxy-addr
diff --git a/server/node_modules/proxy-addr/index.js b/server/node_modules/proxy-addr/index.js
new file mode 100644
index 0000000..a909b05
--- /dev/null
+++ b/server/node_modules/proxy-addr/index.js
@@ -0,0 +1,327 @@
+/*!
+ * proxy-addr
+ * Copyright(c) 2014-2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = proxyaddr
+module.exports.all = alladdrs
+module.exports.compile = compile
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var forwarded = require('forwarded')
+var ipaddr = require('ipaddr.js')
+
+/**
+ * Variables.
+ * @private
+ */
+
+var DIGIT_REGEXP = /^[0-9]+$/
+var isip = ipaddr.isValid
+var parseip = ipaddr.parse
+
+/**
+ * Pre-defined IP ranges.
+ * @private
+ */
+
+var IP_RANGES = {
+  linklocal: ['169.254.0.0/16', 'fe80::/10'],
+  loopback: ['127.0.0.1/8', '::1/128'],
+  uniquelocal: ['10.0.0.0/8', '172.16.0.0/12', '192.168.0.0/16', 'fc00::/7']
+}
+
+/**
+ * Get all addresses in the request, optionally stopping
+ * at the first untrusted.
+ *
+ * @param {Object} request
+ * @param {Function|Array|String} [trust]
+ * @public
+ */
+
+function alladdrs (req, trust) {
+  // get addresses
+  var addrs = forwarded(req)
+
+  if (!trust) {
+    // Return all addresses
+    return addrs
+  }
+
+  if (typeof trust !== 'function') {
+    trust = compile(trust)
+  }
+
+  for (var i = 0; i < addrs.length - 1; i++) {
+    if (trust(addrs[i], i)) continue
+
+    addrs.length = i + 1
+  }
+
+  return addrs
+}
+
+/**
+ * Compile argument into trust function.
+ *
+ * @param {Array|String} val
+ * @private
+ */
+
+function compile (val) {
+  if (!val) {
+    throw new TypeError('argument is required')
+  }
+
+  var trust
+
+  if (typeof val === 'string') {
+    trust = [val]
+  } else if (Array.isArray(val)) {
+    trust = val.slice()
+  } else {
+    throw new TypeError('unsupported trust argument')
+  }
+
+  for (var i = 0; i < trust.length; i++) {
+    val = trust[i]
+
+    if (!Object.prototype.hasOwnProperty.call(IP_RANGES, val)) {
+      continue
+    }
+
+    // Splice in pre-defined range
+    val = IP_RANGES[val]
+    trust.splice.apply(trust, [i, 1].concat(val))
+    i += val.length - 1
+  }
+
+  return compileTrust(compileRangeSubnets(trust))
+}
+
+/**
+ * Compile `arr` elements into range subnets.
+ *
+ * @param {Array} arr
+ * @private
+ */
+
+function compileRangeSubnets (arr) {
+  var rangeSubnets = new Array(arr.length)
+
+  for (var i = 0; i < arr.length; i++) {
+    rangeSubnets[i] = parseipNotation(arr[i])
+  }
+
+  return rangeSubnets
+}
+
+/**
+ * Compile range subnet array into trust function.
+ *
+ * @param {Array} rangeSubnets
+ * @private
+ */
+
+function compileTrust (rangeSubnets) {
+  // Return optimized function based on length
+  var len = rangeSubnets.length
+  return len === 0
+    ? trustNone
+    : len === 1
+      ? trustSingle(rangeSubnets[0])
+      : trustMulti(rangeSubnets)
+}
+
+/**
+ * Parse IP notation string into range subnet.
+ *
+ * @param {String} note
+ * @private
+ */
+
+function parseipNotation (note) {
+  var pos = note.lastIndexOf('/')
+  var str = pos !== -1
+    ? note.substring(0, pos)
+    : note
+
+  if (!isip(str)) {
+    throw new TypeError('invalid IP address: ' + str)
+  }
+
+  var ip = parseip(str)
+
+  if (pos === -1 && ip.kind() === 'ipv6' && ip.isIPv4MappedAddress()) {
+    // Store as IPv4
+    ip = ip.toIPv4Address()
+  }
+
+  var max = ip.kind() === 'ipv6'
+    ? 128
+    : 32
+
+  var range = pos !== -1
+    ? note.substring(pos + 1, note.length)
+    : null
+
+  if (range === null) {
+    range = max
+  } else if (DIGIT_REGEXP.test(range)) {
+    range = parseInt(range, 10)
+  } else if (ip.kind() === 'ipv4' && isip(range)) {
+    range = parseNetmask(range)
+  } else {
+    range = null
+  }
+
+  if (range <= 0 || range > max) {
+    throw new TypeError('invalid range on address: ' + note)
+  }
+
+  return [ip, range]
+}
+
+/**
+ * Parse netmask string into CIDR range.
+ *
+ * @param {String} netmask
+ * @private
+ */
+
+function parseNetmask (netmask) {
+  var ip = parseip(netmask)
+  var kind = ip.kind()
+
+  return kind === 'ipv4'
+    ? ip.prefixLengthFromSubnetMask()
+    : null
+}
+
+/**
+ * Determine address of proxied request.
+ *
+ * @param {Object} request
+ * @param {Function|Array|String} trust
+ * @public
+ */
+
+function proxyaddr (req, trust) {
+  if (!req) {
+    throw new TypeError('req argument is required')
+  }
+
+  if (!trust) {
+    throw new TypeError('trust argument is required')
+  }
+
+  var addrs = alladdrs(req, trust)
+  var addr = addrs[addrs.length - 1]
+
+  return addr
+}
+
+/**
+ * Static trust function to trust nothing.
+ *
+ * @private
+ */
+
+function trustNone () {
+  return false
+}
+
+/**
+ * Compile trust function for multiple subnets.
+ *
+ * @param {Array} subnets
+ * @private
+ */
+
+function trustMulti (subnets) {
+  return function trust (addr) {
+    if (!isip(addr)) return false
+
+    var ip = parseip(addr)
+    var ipconv
+    var kind = ip.kind()
+
+    for (var i = 0; i < subnets.length; i++) {
+      var subnet = subnets[i]
+      var subnetip = subnet[0]
+      var subnetkind = subnetip.kind()
+      var subnetrange = subnet[1]
+      var trusted = ip
+
+      if (kind !== subnetkind) {
+        if (subnetkind === 'ipv4' && !ip.isIPv4MappedAddress()) {
+          // Incompatible IP addresses
+          continue
+        }
+
+        if (!ipconv) {
+          // Convert IP to match subnet IP kind
+          ipconv = subnetkind === 'ipv4'
+            ? ip.toIPv4Address()
+            : ip.toIPv4MappedAddress()
+        }
+
+        trusted = ipconv
+      }
+
+      if (trusted.match(subnetip, subnetrange)) {
+        return true
+      }
+    }
+
+    return false
+  }
+}
+
+/**
+ * Compile trust function for single subnet.
+ *
+ * @param {Object} subnet
+ * @private
+ */
+
+function trustSingle (subnet) {
+  var subnetip = subnet[0]
+  var subnetkind = subnetip.kind()
+  var subnetisipv4 = subnetkind === 'ipv4'
+  var subnetrange = subnet[1]
+
+  return function trust (addr) {
+    if (!isip(addr)) return false
+
+    var ip = parseip(addr)
+    var kind = ip.kind()
+
+    if (kind !== subnetkind) {
+      if (subnetisipv4 && !ip.isIPv4MappedAddress()) {
+        // Incompatible IP addresses
+        return false
+      }
+
+      // Convert IP to match subnet IP kind
+      ip = subnetisipv4
+        ? ip.toIPv4Address()
+        : ip.toIPv4MappedAddress()
+    }
+
+    return ip.match(subnetip, subnetrange)
+  }
+}
diff --git a/server/node_modules/proxy-addr/package.json b/server/node_modules/proxy-addr/package.json
new file mode 100644
index 0000000..24ba8f7
--- /dev/null
+++ b/server/node_modules/proxy-addr/package.json
@@ -0,0 +1,47 @@
+{
+  "name": "proxy-addr",
+  "description": "Determine address of proxied request",
+  "version": "2.0.7",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "keywords": [
+    "ip",
+    "proxy",
+    "x-forwarded-for"
+  ],
+  "repository": "jshttp/proxy-addr",
+  "dependencies": {
+    "forwarded": "0.2.0",
+    "ipaddr.js": "1.9.1"
+  },
+  "devDependencies": {
+    "benchmark": "2.1.4",
+    "beautify-benchmark": "0.2.4",
+    "deep-equal": "1.0.1",
+    "eslint": "7.26.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.23.4",
+    "eslint-plugin-markdown": "2.2.0",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "4.3.1",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "8.4.0",
+    "nyc": "15.1.0"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.10"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/pump/.github/FUNDING.yml b/server/node_modules/pump/.github/FUNDING.yml
new file mode 100644
index 0000000..f6c9139
--- /dev/null
+++ b/server/node_modules/pump/.github/FUNDING.yml
@@ -0,0 +1,2 @@
+github: mafintosh
+tidelift: "npm/pump"
diff --git a/server/node_modules/pump/.travis.yml b/server/node_modules/pump/.travis.yml
new file mode 100644
index 0000000..17f9433
--- /dev/null
+++ b/server/node_modules/pump/.travis.yml
@@ -0,0 +1,5 @@
+language: node_js
+node_js:
+  - "0.10"
+
+script: "npm test"
diff --git a/server/node_modules/pump/LICENSE b/server/node_modules/pump/LICENSE
new file mode 100644
index 0000000..757562e
--- /dev/null
+++ b/server/node_modules/pump/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Mathias Buus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/pump/README.md b/server/node_modules/pump/README.md
new file mode 100644
index 0000000..5dcd8a5
--- /dev/null
+++ b/server/node_modules/pump/README.md
@@ -0,0 +1,74 @@
+# pump
+
+pump is a small node module that pipes streams together and destroys all of them if one of them closes.
+
+```
+npm install pump
+```
+
+[![build status](http://img.shields.io/travis/mafintosh/pump.svg?style=flat)](http://travis-ci.org/mafintosh/pump)
+
+## What problem does it solve?
+
+When using standard `source.pipe(dest)` source will _not_ be destroyed if dest emits close or an error.
+You are also not able to provide a callback to tell when then pipe has finished.
+
+pump does these two things for you
+
+## Usage
+
+Simply pass the streams you want to pipe together to pump and add an optional callback
+
+``` js
+var pump = require('pump')
+var fs = require('fs')
+
+var source = fs.createReadStream('/dev/random')
+var dest = fs.createWriteStream('/dev/null')
+
+pump(source, dest, function(err) {
+  console.log('pipe finished', err)
+})
+
+setTimeout(function() {
+  dest.destroy() // when dest is closed pump will destroy source
+}, 1000)
+```
+
+You can use pump to pipe more than two streams together as well
+
+``` js
+var transform = someTransformStream()
+
+pump(source, transform, anotherTransform, dest, function(err) {
+  console.log('pipe finished', err)
+})
+```
+
+If `source`, `transform`, `anotherTransform` or `dest` closes all of them will be destroyed.
+
+Similarly to `stream.pipe()`, `pump()` returns the last stream passed in, so you can do:
+
+```
+return pump(s1, s2) // returns s2
+```
+
+Note that `pump` attaches error handlers to the streams to do internal error handling, so if `s2` emits an
+error in the above scenario, it will not trigger a `proccess.on('uncaughtException')` if you do not listen for it.
+
+If you want to return a stream that combines *both* s1 and s2 to a single stream use
+[pumpify](https://github.com/mafintosh/pumpify) instead.
+
+## License
+
+MIT
+
+## Related
+
+`pump` is part of the [mississippi stream utility collection](https://github.com/maxogden/mississippi) which includes more useful stream modules similar to this one.
+
+## For enterprise
+
+Available as part of the Tidelift Subscription.
+
+The maintainers of pump and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. [Learn more.](https://tidelift.com/subscription/pkg/npm-pump?utm_source=npm-pump&utm_medium=referral&utm_campaign=enterprise)
diff --git a/server/node_modules/pump/SECURITY.md b/server/node_modules/pump/SECURITY.md
new file mode 100644
index 0000000..da9c516
--- /dev/null
+++ b/server/node_modules/pump/SECURITY.md
@@ -0,0 +1,5 @@
+## Security contact information
+
+To report a security vulnerability, please use the
+[Tidelift security contact](https://tidelift.com/security).
+Tidelift will coordinate the fix and disclosure.
diff --git a/server/node_modules/pump/index.js b/server/node_modules/pump/index.js
new file mode 100644
index 0000000..712c076
--- /dev/null
+++ b/server/node_modules/pump/index.js
@@ -0,0 +1,86 @@
+var once = require('once')
+var eos = require('end-of-stream')
+var fs
+
+try {
+  fs = require('fs') // we only need fs to get the ReadStream and WriteStream prototypes
+} catch (e) {}
+
+var noop = function () {}
+var ancient = typeof process === 'undefined' ? false : /^v?\.0/.test(process.version)
+
+var isFn = function (fn) {
+  return typeof fn === 'function'
+}
+
+var isFS = function (stream) {
+  if (!ancient) return false // newer node version do not need to care about fs is a special way
+  if (!fs) return false // browser
+  return (stream instanceof (fs.ReadStream || noop) || stream instanceof (fs.WriteStream || noop)) && isFn(stream.close)
+}
+
+var isRequest = function (stream) {
+  return stream.setHeader && isFn(stream.abort)
+}
+
+var destroyer = function (stream, reading, writing, callback) {
+  callback = once(callback)
+
+  var closed = false
+  stream.on('close', function () {
+    closed = true
+  })
+
+  eos(stream, {readable: reading, writable: writing}, function (err) {
+    if (err) return callback(err)
+    closed = true
+    callback()
+  })
+
+  var destroyed = false
+  return function (err) {
+    if (closed) return
+    if (destroyed) return
+    destroyed = true
+
+    if (isFS(stream)) return stream.close(noop) // use close for fs streams to avoid fd leaks
+    if (isRequest(stream)) return stream.abort() // request.destroy just do .end - .abort is what we want
+
+    if (isFn(stream.destroy)) return stream.destroy()
+
+    callback(err || new Error('stream was destroyed'))
+  }
+}
+
+var call = function (fn) {
+  fn()
+}
+
+var pipe = function (from, to) {
+  return from.pipe(to)
+}
+
+var pump = function () {
+  var streams = Array.prototype.slice.call(arguments)
+  var callback = isFn(streams[streams.length - 1] || noop) && streams.pop() || noop
+
+  if (Array.isArray(streams[0])) streams = streams[0]
+  if (streams.length < 2) throw new Error('pump requires two streams per minimum')
+
+  var error
+  var destroys = streams.map(function (stream, i) {
+    var reading = i < streams.length - 1
+    var writing = i > 0
+    return destroyer(stream, reading, writing, function (err) {
+      if (!error) error = err
+      if (err) destroys.forEach(call)
+      if (reading) return
+      destroys.forEach(call)
+      callback(error)
+    })
+  })
+
+  return streams.reduce(pipe)
+}
+
+module.exports = pump
diff --git a/server/node_modules/pump/package.json b/server/node_modules/pump/package.json
new file mode 100644
index 0000000..976555c
--- /dev/null
+++ b/server/node_modules/pump/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "pump",
+  "version": "3.0.3",
+  "repository": "git://github.com/mafintosh/pump.git",
+  "license": "MIT",
+  "description": "pipe streams together and close all of them if one of them closes",
+  "browser": {
+    "fs": false
+  },
+  "keywords": [
+    "streams",
+    "pipe",
+    "destroy",
+    "callback"
+  ],
+  "author": "Mathias Buus Madsen <mathiasbuus@gmail.com>",
+  "dependencies": {
+    "end-of-stream": "^1.1.0",
+    "once": "^1.3.1"
+  },
+  "scripts": {
+    "test": "node test-browser.js && node test-node.js"
+  }
+}
diff --git a/server/node_modules/pump/test-browser.js b/server/node_modules/pump/test-browser.js
new file mode 100644
index 0000000..9a06c8a
--- /dev/null
+++ b/server/node_modules/pump/test-browser.js
@@ -0,0 +1,66 @@
+var stream = require('stream')
+var pump = require('./index')
+
+var rs = new stream.Readable()
+var ws = new stream.Writable()
+
+rs._read = function (size) {
+  this.push(Buffer(size).fill('abc'))
+}
+
+ws._write = function (chunk, encoding, cb) {
+  setTimeout(function () {
+    cb()
+  }, 100)
+}
+
+var toHex = function () {
+  var reverse = new (require('stream').Transform)()
+
+  reverse._transform = function (chunk, enc, callback) {
+    reverse.push(chunk.toString('hex'))
+    callback()
+  }
+
+  return reverse
+}
+
+var wsClosed = false
+var rsClosed = false
+var callbackCalled = false
+
+var check = function () {
+  if (wsClosed && rsClosed && callbackCalled) {
+    console.log('test-browser.js passes')
+    clearTimeout(timeout)
+  }
+}
+
+ws.on('finish', function () {
+  wsClosed = true
+  check()
+})
+
+rs.on('end', function () {
+  rsClosed = true
+  check()
+})
+
+var res = pump(rs, toHex(), toHex(), toHex(), ws, function () {
+  callbackCalled = true
+  check()
+})
+
+if (res !== ws) {
+  throw new Error('should return last stream')
+}
+
+setTimeout(function () {
+  rs.push(null)
+  rs.emit('close')
+}, 1000)
+
+var timeout = setTimeout(function () {
+  check()
+  throw new Error('timeout')
+}, 5000)
diff --git a/server/node_modules/pump/test-node.js b/server/node_modules/pump/test-node.js
new file mode 100644
index 0000000..561251a
--- /dev/null
+++ b/server/node_modules/pump/test-node.js
@@ -0,0 +1,53 @@
+var pump = require('./index')
+
+var rs = require('fs').createReadStream('/dev/random')
+var ws = require('fs').createWriteStream('/dev/null')
+
+var toHex = function () {
+  var reverse = new (require('stream').Transform)()
+
+  reverse._transform = function (chunk, enc, callback) {
+    reverse.push(chunk.toString('hex'))
+    callback()
+  }
+
+  return reverse
+}
+
+var wsClosed = false
+var rsClosed = false
+var callbackCalled = false
+
+var check = function () {
+  if (wsClosed && rsClosed && callbackCalled) {
+    console.log('test-node.js passes')
+    clearTimeout(timeout)
+  }
+}
+
+ws.on('close', function () {
+  wsClosed = true
+  check()
+})
+
+rs.on('close', function () {
+  rsClosed = true
+  check()
+})
+
+var res = pump(rs, toHex(), toHex(), toHex(), ws, function () {
+  callbackCalled = true
+  check()
+})
+
+if (res !== ws) {
+  throw new Error('should return last stream')
+}
+
+setTimeout(function () {
+  rs.destroy()
+}, 1000)
+
+var timeout = setTimeout(function () {
+  throw new Error('timeout')
+}, 5000)
diff --git a/server/node_modules/qs/.editorconfig b/server/node_modules/qs/.editorconfig
new file mode 100644
index 0000000..6adecfb
--- /dev/null
+++ b/server/node_modules/qs/.editorconfig
@@ -0,0 +1,46 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+max_line_length = 160
+quote_type = single
+
+[test/*]
+max_line_length = off
+
+[LICENSE.md]
+indent_size = off
+
+[*.md]
+max_line_length = off
+
+[*.json]
+max_line_length = off
+
+[Makefile]
+max_line_length = off
+
+[CHANGELOG.md]
+indent_style = space
+indent_size = 2
+
+[LICENSE]
+indent_size = 2
+max_line_length = off
+
+[coverage/**/*]
+indent_size = off
+indent_style = off
+indent = off
+max_line_length = off
+
+[.nycrc]
+indent_style = tab
+
+[tea.yaml]
+indent_size = 2
diff --git a/server/node_modules/qs/.github/FUNDING.yml b/server/node_modules/qs/.github/FUNDING.yml
new file mode 100644
index 0000000..0355f4f
--- /dev/null
+++ b/server/node_modules/qs/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/qs
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with a single custom sponsorship URL
diff --git a/server/node_modules/qs/.github/SECURITY.md b/server/node_modules/qs/.github/SECURITY.md
new file mode 100644
index 0000000..b499cb6
--- /dev/null
+++ b/server/node_modules/qs/.github/SECURITY.md
@@ -0,0 +1,11 @@
+# Security
+
+Please file a private vulnerability report via GitHub, email [@ljharb](https://github.com/ljharb), or see https://tidelift.com/security if you have a potential security vulnerability to report.
+
+## Incident Response Plan
+
+Please see our [Incident Response Plan](https://github.com/ljharb/.github/blob/main/INCIDENT_RESPONSE_PLAN.md).
+
+## Threat Model
+
+Please see [THREAT_MODEL.md](./THREAT_MODEL.md).
diff --git a/server/node_modules/qs/.github/THREAT_MODEL.md b/server/node_modules/qs/.github/THREAT_MODEL.md
new file mode 100644
index 0000000..7e6fef1
--- /dev/null
+++ b/server/node_modules/qs/.github/THREAT_MODEL.md
@@ -0,0 +1,78 @@
+## Threat Model for qs (querystring parsing library)
+
+### 1. Library Overview
+
+- **Library Name:** qs
+- **Brief Description:** A JavaScript library for parsing and stringifying URL query strings, supporting nested objects and arrays. It is widely used in Node.js and web applications for processing query parameters[2][6][8].
+- **Key Public APIs/Functions:** `qs.parse()`, `qs.stringify()`
+
+### 2. Define Scope
+
+This threat model focuses on the core parsing and stringifying functionality, specifically the handling of nested objects and arrays, option validation, and cycle management in stringification.
+
+### 3. Conceptual System Diagram
+
+```
+Caller Application → qs.parse(input, options) → Parsing Engine → Output Object
+                           │
+                           └→ Options Handling
+
+Caller Application → qs.stringify(obj, options) → Stringifying Engine → Output String
+                           │
+                           └→ Options Handling
+                           └→ Cycle Tracking
+```
+
+**Trust Boundaries:**
+- **Input string (parse):** May come from untrusted sources (e.g., user input, network requests)
+- **Input object (stringify):** May contain cycles, which can lead to infinite loops during stringification
+- **Options:** Provided by the caller
+- **Cycle Tracking:** Used only during stringification to detect and handle circular references
+
+### 4. Identify Assets
+
+- **Integrity of parsed output:** Prevent malicious manipulation of the output object structure, especially ensuring builtins/globals are not modified as a result of parse[3][4][8].
+- **Confidentiality of processed data:** Avoid leaking sensitive information through errors or output.
+- **Availability/performance for host application:** Prevent crashes or resource exhaustion in the consuming application.
+- **Security of host application:** Prevent the library from being a vector for attacks (e.g., prototype pollution, DoS).
+- **Reputation of library:** Maintain trust by avoiding supply chain attacks and vulnerabilities[1].
+
+### 5. Identify Threats
+
+| Component / API / Interaction         | S  | T  | R  | I  | D  | E  |
+|---------------------------------------|----|----|----|----|----|----|
+| Public API Call (`parse`)             | –  | ✓  | –  | ✓  | ✓  | ✓  |
+| Public API Call (`stringify`)         | –  | ✓  | –  | ✓  | ✓  | –  |
+| Options Handling                      | ✓  | ✓  | –  | ✓  | –  | ✓  |
+| Dependency Interaction                | –  | –  | –  | –  | ✓  | –  |
+
+**Key Threats:**
+- **Tampering:** Malicious input can, if not prevented, alter parsed output (e.g., prototype pollution via `__proto__`, modification of builtins/globals)[3][4][8].
+- **Information Disclosure:** Error messages may expose internal details or sensitive data.
+- **Denial of Service:** Large or malformed input can exhaust memory or CPU.
+- **Elevation of Privilege:** Prototype pollution can lead to unintended privilege escalation in the host application[3][4][8].
+
+### 6. Mitigation/Countermeasures
+
+| Threat Identified                                 | Proposed Mitigation |
+|---------------------------------------------------|---------------------|
+| Tampering (malicious input, prototype pollution)  | Strict input validation; keep `allowPrototypes: false` by default; use `plainObjects` for output; ensure builtins/globals are never modified by parse[4][8]. |
+| Information Disclosure (error messages)           | Generic error messages without stack traces or internal paths. |
+| Denial of Service (memory/CPU exhaustion)         | Enforce `arrayLimit` and `parameterLimit` with safe defaults; enable `throwOnLimitExceeded`; limit nesting depth[7]. |
+| Elevation of Privilege (prototype pollution)      | Keep `allowPrototypes: false`; validate options against allowlist; use `plainObjects` to avoid prototype pollution[4][8]. |
+
+### 7. Risk Ranking
+
+- **High:** Denial of Service via array parsing or malformed input (historical vulnerability)
+- **Medium:** Prototype pollution via options or input (if `allowPrototypes` enabled)
+- **Low:** Information disclosure in errors
+
+### 8. Next Steps & Review
+
+1. **Audit option validation logic.**
+2. **Add depth limiting to nested parsing and stringification.**
+3. **Implement fuzz testing for parser and stringifier edge cases.**
+4. **Regularly review dependencies for vulnerabilities.**
+5. **Keep documentation and threat model up to date.**
+6. **Ensure builtins/globals are never modified as a result of parse.**
+7. **Support round-trip consistency between parse and stringify as a non-security goal, with the right options[5][9].**
diff --git a/server/node_modules/qs/.nycrc b/server/node_modules/qs/.nycrc
new file mode 100644
index 0000000..1d57cab
--- /dev/null
+++ b/server/node_modules/qs/.nycrc
@@ -0,0 +1,13 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"lines": 86,
+	"statements": 85.93,
+	"functions": 82.43,
+	"branches": 76.06,
+	"exclude": [
+		"coverage",
+		"dist"
+	]
+}
diff --git a/server/node_modules/qs/CHANGELOG.md b/server/node_modules/qs/CHANGELOG.md
new file mode 100644
index 0000000..35828d5
--- /dev/null
+++ b/server/node_modules/qs/CHANGELOG.md
@@ -0,0 +1,631 @@
+## **6.14.1**
+- [Fix] ensure arrayLength applies to `[]` notation as well
+- [Fix] `parse`: when a custom decoder returns `null` for a key, ignore that key
+- [Refactor] `parse`: extract key segment splitting helper
+- [meta] add threat model
+- [actions] add workflow permissions
+- [Tests] `stringify`: increase coverage
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `npmignore`, `es-value-fixtures`, `for-each`, `object-inspect`
+
+## **6.14.0**
+- [New] `parse`: add `throwOnParameterLimitExceeded` option (#517)
+- [Refactor] `parse`: use `utils.combine` more
+- [patch] `parse`: add explicit `throwOnLimitExceeded` default
+- [actions] use shared action; re-add finishers
+- [meta] Fix changelog formatting bug
+- [Deps] update `side-channel`
+- [Dev Deps] update `es-value-fixtures`, `has-bigints`, `has-proto`, `has-symbols`
+- [Tests] increase coverage
+
+## **6.13.1**
+- [Fix] `stringify`: avoid a crash when a `filter` key is `null`
+- [Fix] `utils.merge`: functions should not be stringified into keys
+- [Fix] `parse`: avoid a crash with interpretNumericEntities: true, comma: true, and iso charset
+- [Fix] `stringify`: ensure a non-string `filter` does not crash
+- [Refactor] use `__proto__` syntax instead of `Object.create` for null objects
+- [Refactor] misc cleanup
+- [Tests] `utils.merge`: add some coverage
+- [Tests] fix a test case
+- [actions] split out node 10-20, and 20+
+- [Dev Deps] update `es-value-fixtures`, `mock-property`, `object-inspect`, `tape`
+
+## **6.13.0**
+- [New] `parse`: add `strictDepth` option (#511)
+- [Tests] use `npm audit` instead of `aud`
+
+## **6.12.3**
+- [Fix] `parse`: properly account for `strictNullHandling` when `allowEmptyArrays`
+- [meta] fix changelog indentation
+
+## **6.12.2**
+- [Fix] `parse`: parse encoded square brackets (#506)
+- [readme] add CII best practices badge
+
+## **6.12.1**
+- [Fix] `parse`: Disable `decodeDotInKeys` by default to restore previous behavior (#501)
+- [Performance] `utils`: Optimize performance under large data volumes, reduce memory usage, and speed up processing (#502)
+- [Refactor] `utils`: use `+=`
+- [Tests] increase coverage
+
+## **6.12.0**
+
+- [New] `parse`/`stringify`: add `decodeDotInKeys`/`encodeDotKeys` options (#488)
+- [New] `parse`: add `duplicates` option
+- [New] `parse`/`stringify`: add `allowEmptyArrays` option to allow [] in object values (#487)
+- [Refactor] `parse`/`stringify`: move allowDots config logic to its own variable
+- [Refactor] `stringify`: move option-handling code into `normalizeStringifyOptions`
+- [readme] update readme, add logos (#484)
+- [readme] `stringify`: clarify default `arrayFormat` behavior
+- [readme] fix line wrapping
+- [readme] remove dead badges
+- [Deps] update `side-channel`
+- [meta] make the dist build 50% smaller
+- [meta] add `sideEffects` flag
+- [meta] run build in prepack, not prepublish
+- [Tests] `parse`: remove useless tests; add coverage
+- [Tests] `stringify`: increase coverage
+- [Tests] use `mock-property`
+- [Tests] `stringify`: improve coverage
+- [Dev Deps] update `@ljharb/eslint-config `, `aud`, `has-override-mistake`, `has-property-descriptors`, `mock-property`, `npmignore`, `object-inspect`, `tape`
+- [Dev Deps] pin `glob`, since v10.3.8+ requires a broken `jackspeak`
+- [Dev Deps] pin `jackspeak` since 2.1.2+ depends on npm aliases, which kill the install process in npm < 6
+
+## **6.11.2**
+- [Fix] `parse`: Fix parsing when the global Object prototype is frozen (#473)
+- [Tests] add passing test cases with empty keys (#473)
+
+## **6.11.1**
+- [Fix] `stringify`: encode comma values more consistently (#463)
+- [readme] add usage of `filter` option for injecting custom serialization, i.e. of custom types (#447)
+- [meta] remove extraneous code backticks (#457)
+- [meta] fix changelog markdown
+- [actions] update checkout action
+- [actions] restrict action permissions
+- [Dev Deps] update `@ljharb/eslint-config`, `aud`, `object-inspect`, `tape`
+
+## **6.11.0**
+- [New] [Fix] `stringify`: revert 0e903c0; add `commaRoundTrip` option (#442)
+- [readme] fix version badge
+
+## **6.10.5**
+- [Fix] `stringify`: with `arrayFormat: comma`, properly include an explicit `[]` on a single-item array (#434)
+
+## **6.10.4**
+- [Fix] `stringify`: with `arrayFormat: comma`, include an explicit `[]` on a single-item array (#441)
+- [meta] use `npmignore` to autogenerate an npmignore file
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `has-symbol`, `object-inspect`, `tape`
+
+## **6.10.3**
+- [Fix] `parse`: ignore `__proto__` keys (#428)
+- [Robustness] `stringify`: avoid relying on a global `undefined` (#427)
+- [actions] reuse common workflows
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `object-inspect`, `tape`
+
+## **6.10.2**
+- [Fix] `stringify`: actually fix cyclic references (#426)
+- [Fix] `stringify`: avoid encoding arrayformat comma when `encodeValuesOnly = true` (#424)
+- [readme] remove travis badge; add github actions/codecov badges; update URLs
+- [Docs] add note and links for coercing primitive values (#408)
+- [actions] update codecov uploader
+- [actions] update workflows
+- [Tests] clean up stringify tests slightly
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `object-inspect`, `safe-publish-latest`, `tape`
+
+## **6.10.1**
+- [Fix] `stringify`: avoid exception on repeated object values (#402)
+
+## **6.10.0**
+- [New] `stringify`: throw on cycles, instead of an infinite loop (#395, #394, #393)
+- [New] `parse`: add `allowSparse` option for collapsing arrays with missing indices (#312)
+- [meta] fix README.md (#399)
+- [meta] only run `npm run dist` in publish, not install
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `has-symbols`, `tape`
+- [Tests] fix tests on node v0.6
+- [Tests] use `ljharb/actions/node/install` instead of `ljharb/actions/node/run`
+- [Tests] Revert "[meta] ignore eclint transitive audit warning"
+
+## **6.9.7**
+- [Fix] `parse`: ignore `__proto__` keys (#428)
+- [Fix] `stringify`: avoid encoding arrayformat comma when `encodeValuesOnly = true` (#424)
+- [Robustness] `stringify`: avoid relying on a global `undefined` (#427)
+- [readme] remove travis badge; add github actions/codecov badges; update URLs
+- [Docs] add note and links for coercing primitive values (#408)
+- [Tests] clean up stringify tests slightly
+- [meta] fix README.md (#399)
+- Revert "[meta] ignore eclint transitive audit warning"
+- [actions] backport actions from main
+- [Dev Deps] backport updates from main
+
+## **6.9.6**
+- [Fix] restore `dist` dir; mistakenly removed in d4f6c32
+
+## **6.9.5**
+- [Fix] `stringify`: do not encode parens for RFC1738
+- [Fix] `stringify`: fix arrayFormat comma with empty array/objects (#350)
+- [Refactor] `format`: remove `util.assign` call
+- [meta] add "Allow Edits" workflow; update rebase workflow
+- [actions] switch Automatic Rebase workflow to `pull_request_target` event
+- [Tests] `stringify`: add tests for #378
+- [Tests] migrate tests to Github Actions
+- [Tests] run `nyc` on all tests; use `tape` runner
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `browserify`, `mkdirp`, `object-inspect`, `tape`; add `aud`
+
+## **6.9.4**
+- [Fix] `stringify`: when `arrayFormat` is `comma`, respect `serializeDate` (#364)
+- [Refactor] `stringify`: reduce branching (part of #350)
+- [Refactor] move `maybeMap` to `utils`
+- [Dev Deps] update `browserify`, `tape`
+
+## **6.9.3**
+- [Fix] proper comma parsing of URL-encoded commas (#361)
+- [Fix] parses comma delimited array while having percent-encoded comma treated as normal text (#336)
+
+## **6.9.2**
+- [Fix] `parse`: Fix parsing array from object with `comma` true (#359)
+- [Fix] `parse`: throw a TypeError instead of an Error for bad charset (#349)
+- [meta] ignore eclint transitive audit warning
+- [meta] fix indentation in package.json
+- [meta] add tidelift marketing copy
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `object-inspect`, `has-symbols`, `tape`, `mkdirp`, `iconv-lite`
+- [actions] add automatic rebasing / merge commit blocking
+
+## **6.9.1**
+- [Fix] `parse`: with comma true, handle field that holds an array of arrays (#335)
+- [Fix] `parse`: with comma true, do not split non-string values (#334)
+- [meta] add `funding` field
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`
+- [Tests] use shared travis-ci config
+
+## **6.9.0**
+- [New] `parse`/`stringify`: Pass extra key/value argument to `decoder` (#333)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `evalmd`
+- [Tests] `parse`: add passing `arrayFormat` tests
+- [Tests] add `posttest` using `npx aud` to run `npm audit` without a lockfile
+- [Tests] up to `node` `v12.10`, `v11.15`, `v10.16`, `v8.16`
+- [Tests] `Buffer.from` in node v5.0-v5.9 and v4.0-v4.4 requires a TypedArray
+
+## **6.8.3**
+- [Fix] `parse`: ignore `__proto__` keys (#428)
+- [Robustness] `stringify`: avoid relying on a global `undefined` (#427)
+- [Fix] `stringify`: avoid encoding arrayformat comma when `encodeValuesOnly = true` (#424)
+- [readme] remove travis badge; add github actions/codecov badges; update URLs
+- [Tests] clean up stringify tests slightly
+- [Docs] add note and links for coercing primitive values (#408)
+- [meta] fix README.md (#399)
+- [actions] backport actions from main
+- [Dev Deps] backport updates from main
+- [Refactor] `stringify`: reduce branching
+- [meta] do not publish workflow files
+
+## **6.8.2**
+- [Fix] proper comma parsing of URL-encoded commas (#361)
+- [Fix] parses comma delimited array while having percent-encoded comma treated as normal text (#336)
+
+## **6.8.1**
+- [Fix] `parse`: Fix parsing array from object with `comma` true (#359)
+- [Fix] `parse`: throw a TypeError instead of an Error for bad charset (#349)
+- [Fix] `parse`: with comma true, handle field that holds an array of arrays (#335)
+- [fix] `parse`: with comma true, do not split non-string values (#334)
+- [meta] add tidelift marketing copy
+- [meta] add `funding` field
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `tape`, `safe-publish-latest`, `evalmd`, `has-symbols`, `iconv-lite`, `mkdirp`, `object-inspect`
+- [Tests] `parse`: add passing `arrayFormat` tests
+- [Tests] use shared travis-ci configs
+- [Tests] `Buffer.from` in node v5.0-v5.9 and v4.0-v4.4 requires a TypedArray
+- [actions] add automatic rebasing / merge commit blocking
+
+## **6.8.0**
+- [New] add `depth=false` to preserve the original key; [Fix] `depth=0` should preserve the original key (#326)
+- [New] [Fix] stringify symbols and bigints
+- [Fix] ensure node 0.12 can stringify Symbols
+- [Fix] fix for an impossible situation: when the formatter is called with a non-string value
+- [Refactor] `formats`: tiny bit of cleanup.
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `browserify`, `safe-publish-latest`, `iconv-lite`, `tape`
+- [Tests] add tests for `depth=0` and `depth=false` behavior, both current and intuitive/intended (#326)
+- [Tests] use `eclint` instead of `editorconfig-tools`
+- [docs] readme: add security note
+- [meta] add github sponsorship
+- [meta] add FUNDING.yml
+- [meta] Clean up license text so it’s properly detected as BSD-3-Clause
+
+## **6.7.3**
+- [Fix] `parse`: ignore `__proto__` keys (#428)
+- [Fix] `stringify`: avoid encoding arrayformat comma when `encodeValuesOnly = true` (#424)
+- [Robustness] `stringify`: avoid relying on a global `undefined` (#427)
+- [readme] remove travis badge; add github actions/codecov badges; update URLs
+- [Docs] add note and links for coercing primitive values (#408)
+- [meta] fix README.md (#399)
+- [meta] do not publish workflow files
+- [actions] backport actions from main
+- [Dev Deps] backport updates from main
+- [Tests] use `nyc` for coverage
+- [Tests] clean up stringify tests slightly
+
+## **6.7.2**
+- [Fix] proper comma parsing of URL-encoded commas (#361)
+- [Fix] parses comma delimited array while having percent-encoded comma treated as normal text (#336)
+
+## **6.7.1**
+- [Fix] `parse`: Fix parsing array from object with `comma` true (#359)
+- [Fix] `parse`: with comma true, handle field that holds an array of arrays (#335)
+- [fix] `parse`: with comma true, do not split non-string values (#334)
+- [Fix] `parse`: throw a TypeError instead of an Error for bad charset (#349)
+- [Fix] fix for an impossible situation: when the formatter is called with a non-string value
+- [Refactor] `formats`: tiny bit of cleanup.
+- readme: add security note
+- [meta] add tidelift marketing copy
+- [meta] add `funding` field
+- [meta] add FUNDING.yml
+- [meta] Clean up license text so it’s properly detected as BSD-3-Clause
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `tape`, `safe-publish-latest`, `evalmd`, `iconv-lite`, `mkdirp`, `object-inspect`, `browserify`
+- [Tests] `parse`: add passing `arrayFormat` tests
+- [Tests] use shared travis-ci configs
+- [Tests] `Buffer.from` in node v5.0-v5.9 and v4.0-v4.4 requires a TypedArray
+- [Tests] add tests for `depth=0` and `depth=false` behavior, both current and intuitive/intended
+- [Tests] use `eclint` instead of `editorconfig-tools`
+- [actions] add automatic rebasing / merge commit blocking
+
+## **6.7.0**
+- [New] `stringify`/`parse`: add `comma` as an `arrayFormat` option (#276, #219)
+- [Fix] correctly parse nested arrays (#212)
+- [Fix] `utils.merge`: avoid a crash with a null target and a truthy non-array source, also with an array source
+- [Robustness] `stringify`: cache `Object.prototype.hasOwnProperty`
+- [Refactor] `utils`: `isBuffer`: small tweak; add tests
+- [Refactor] use cached `Array.isArray`
+- [Refactor] `parse`/`stringify`: make a function to normalize the options
+- [Refactor] `utils`: reduce observable [[Get]]s
+- [Refactor] `stringify`/`utils`: cache `Array.isArray`
+- [Tests] always use `String(x)` over `x.toString()`
+- [Tests] fix Buffer tests to work in node < 4.5 and node < 5.10
+- [Tests] temporarily allow coverage to fail
+
+## **6.6.1**
+- [Fix] `parse`: ignore `__proto__` keys (#428)
+- [Fix] fix for an impossible situation: when the formatter is called with a non-string value
+- [Fix] `utils.merge`: avoid a crash with a null target and an array source
+- [Fix] `utils.merge`: avoid a crash with a null target and a truthy non-array source
+- [Fix] correctly parse nested arrays
+- [Robustness] `stringify`: avoid relying on a global `undefined` (#427)
+- [Robustness] `stringify`: cache `Object.prototype.hasOwnProperty`
+- [Refactor] `formats`: tiny bit of cleanup.
+- [Refactor] `utils`: `isBuffer`: small tweak; add tests
+- [Refactor]: `stringify`/`utils`: cache `Array.isArray`
+- [Refactor] `utils`: reduce observable [[Get]]s
+- [Refactor] use cached `Array.isArray`
+- [Refactor] `parse`/`stringify`: make a function to normalize the options
+- [readme] remove travis badge; add github actions/codecov badges; update URLs
+- [Docs] Clarify the need for "arrayLimit" option
+- [meta] fix README.md (#399)
+- [meta] do not publish workflow files
+- [meta] Clean up license text so it’s properly detected as BSD-3-Clause
+- [meta] add FUNDING.yml
+- [meta] Fixes typo in CHANGELOG.md
+- [actions] backport actions from main
+- [Tests] fix Buffer tests to work in node < 4.5 and node < 5.10
+- [Tests] always use `String(x)` over `x.toString()`
+- [Dev Deps] backport from main
+
+## **6.6.0**
+- [New] Add support for iso-8859-1, utf8 "sentinel" and numeric entities (#268)
+- [New] move two-value combine to a `utils` function (#189)
+- [Fix] `stringify`: fix a crash with `strictNullHandling` and a custom `filter`/`serializeDate` (#279)
+- [Fix] when `parseArrays` is false, properly handle keys ending in `[]` (#260)
+- [Fix] `stringify`: do not crash in an obscure combo of `interpretNumericEntities`, a bad custom `decoder`, & `iso-8859-1`
+- [Fix] `utils`: `merge`: fix crash when `source` is a truthy primitive & no options are provided
+- [refactor] `stringify`: Avoid arr = arr.concat(...), push to the existing instance (#269)
+- [Refactor] `parse`: only need to reassign the var once
+- [Refactor] `parse`/`stringify`: clean up `charset` options checking; fix defaults
+- [Refactor] add missing defaults
+- [Refactor] `parse`: one less `concat` call
+- [Refactor] `utils`: `compactQueue`: make it explicitly side-effecting
+- [Dev Deps] update `browserify`, `eslint`, `@ljharb/eslint-config`, `iconv-lite`, `safe-publish-latest`, `tape`
+- [Tests] up to `node` `v10.10`, `v9.11`, `v8.12`, `v6.14`, `v4.9`; pin included builds to LTS
+
+## **6.5.3**
+- [Fix] `parse`: ignore `__proto__` keys (#428)
+- [Fix] `utils.merge`: avoid a crash with a null target and a truthy non-array source
+- [Fix] correctly parse nested arrays
+- [Fix] `stringify`: fix a crash with `strictNullHandling` and a custom `filter`/`serializeDate` (#279)
+- [Fix] `utils`: `merge`: fix crash when `source` is a truthy primitive & no options are provided
+- [Fix] when `parseArrays` is false, properly handle keys ending in `[]`
+- [Fix] fix for an impossible situation: when the formatter is called with a non-string value
+- [Fix] `utils.merge`: avoid a crash with a null target and an array source
+- [Refactor] `utils`: reduce observable [[Get]]s
+- [Refactor] use cached `Array.isArray`
+- [Refactor] `stringify`: Avoid arr = arr.concat(...), push to the existing instance (#269)
+- [Refactor] `parse`: only need to reassign the var once
+- [Robustness] `stringify`: avoid relying on a global `undefined` (#427)
+- [readme] remove travis badge; add github actions/codecov badges; update URLs
+- [Docs] Clean up license text so it’s properly detected as BSD-3-Clause
+- [Docs] Clarify the need for "arrayLimit" option
+- [meta] fix README.md (#399)
+- [meta] add FUNDING.yml
+- [actions] backport actions from main
+- [Tests] always use `String(x)` over `x.toString()`
+- [Tests] remove nonexistent tape option
+- [Dev Deps] backport from main
+
+## **6.5.2**
+- [Fix] use `safer-buffer` instead of `Buffer` constructor
+- [Refactor] utils: `module.exports` one thing, instead of mutating `exports` (#230)
+- [Dev Deps] update `browserify`, `eslint`, `iconv-lite`, `safer-buffer`, `tape`, `browserify`
+
+## **6.5.1**
+- [Fix] Fix parsing & compacting very deep objects (#224)
+- [Refactor] name utils functions
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `tape`
+- [Tests] up to `node` `v8.4`; use `nvm install-latest-npm` so newer npm doesn’t break older node
+- [Tests] Use precise dist for Node.js 0.6 runtime (#225)
+- [Tests] make 0.6 required, now that it’s passing
+- [Tests] on `node` `v8.2`; fix npm on node 0.6
+
+## **6.5.0**
+- [New] add `utils.assign`
+- [New] pass default encoder/decoder to custom encoder/decoder functions (#206)
+- [New] `parse`/`stringify`: add `ignoreQueryPrefix`/`addQueryPrefix` options, respectively (#213)
+- [Fix] Handle stringifying empty objects with addQueryPrefix (#217)
+- [Fix] do not mutate `options` argument (#207)
+- [Refactor] `parse`: cache index to reuse in else statement (#182)
+- [Docs] add various badges to readme (#208)
+- [Dev Deps] update `eslint`, `browserify`, `iconv-lite`, `tape`
+- [Tests] up to `node` `v8.1`, `v7.10`, `v6.11`; npm v4.6 breaks on node < v1; npm v5+ breaks on node < v4
+- [Tests] add `editorconfig-tools`
+
+## **6.4.1**
+- [Fix] `parse`: ignore `__proto__` keys (#428)
+- [Fix] fix for an impossible situation: when the formatter is called with a non-string value
+- [Fix] use `safer-buffer` instead of `Buffer` constructor
+- [Fix] `utils.merge`: avoid a crash with a null target and an array source
+- [Fix] `utils.merge`: avoid a crash with a null target and a truthy non-array source
+- [Fix] `stringify`: fix a crash with `strictNullHandling` and a custom `filter`/`serializeDate` (#279)
+- [Fix] `utils`: `merge`: fix crash when `source` is a truthy primitive & no options are provided
+- [Fix] when `parseArrays` is false, properly handle keys ending in `[]`
+- [Robustness] `stringify`: avoid relying on a global `undefined` (#427)
+- [Refactor] use cached `Array.isArray`
+- [Refactor] `stringify`: Avoid arr = arr.concat(...), push to the existing instance (#269)
+- [readme] remove travis badge; add github actions/codecov badges; update URLs
+- [Docs] Clarify the need for "arrayLimit" option
+- [meta] fix README.md (#399)
+- [meta] Clean up license text so it’s properly detected as BSD-3-Clause
+- [meta] add FUNDING.yml
+- [actions] backport actions from main
+- [Tests] remove nonexistent tape option
+- [Dev Deps] backport from main
+
+## **6.4.0**
+- [New] `qs.stringify`: add `encodeValuesOnly` option
+- [Fix] follow `allowPrototypes` option during merge (#201, #201)
+- [Fix] support keys starting with brackets (#202, #200)
+- [Fix] chmod a-x
+- [Dev Deps] update `eslint`
+- [Tests] up to `node` `v7.7`, `v6.10`,` v4.8`; disable osx builds since they block linux builds
+- [eslint] reduce warnings
+
+## **6.3.3**
+- [Fix] `parse`: ignore `__proto__` keys (#428)
+- [Fix] fix for an impossible situation: when the formatter is called with a non-string value
+- [Fix] `utils.merge`: avoid a crash with a null target and an array source
+- [Fix] `utils.merge`: avoid a crash with a null target and a truthy non-array source
+- [Fix] `stringify`: fix a crash with `strictNullHandling` and a custom `filter`/`serializeDate` (#279)
+- [Fix] `utils`: `merge`: fix crash when `source` is a truthy primitive & no options are provided
+- [Fix] when `parseArrays` is false, properly handle keys ending in `[]`
+- [Robustness] `stringify`: avoid relying on a global `undefined` (#427)
+- [Refactor] use cached `Array.isArray`
+- [Refactor] `stringify`: Avoid arr = arr.concat(...), push to the existing instance (#269)
+- [Docs] Clarify the need for "arrayLimit" option
+- [meta] fix README.md (#399)
+- [meta] Clean up license text so it’s properly detected as BSD-3-Clause
+- [meta] add FUNDING.yml
+- [actions] backport actions from main
+- [Tests] use `safer-buffer` instead of `Buffer` constructor
+- [Tests] remove nonexistent tape option
+- [Dev Deps] backport from main
+
+## **6.3.2**
+- [Fix] follow `allowPrototypes` option during merge (#201, #200)
+- [Dev Deps] update `eslint`
+- [Fix] chmod a-x
+- [Fix] support keys starting with brackets (#202, #200)
+- [Tests] up to `node` `v7.7`, `v6.10`,` v4.8`; disable osx builds since they block linux builds
+
+## **6.3.1**
+- [Fix] ensure that `allowPrototypes: false` does not ever shadow Object.prototype properties (thanks, @snyk!)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `browserify`, `iconv-lite`, `qs-iconv`, `tape`
+- [Tests] on all node minors; improve test matrix
+- [Docs] document stringify option `allowDots` (#195)
+- [Docs] add empty object and array values example (#195)
+- [Docs] Fix minor inconsistency/typo (#192)
+- [Docs] document stringify option `sort` (#191)
+- [Refactor] `stringify`: throw faster with an invalid encoder
+- [Refactor] remove unnecessary escapes (#184)
+- Remove contributing.md, since `qs` is no longer part of `hapi` (#183)
+
+## **6.3.0**
+- [New] Add support for RFC 1738 (#174, #173)
+- [New] `stringify`: Add `serializeDate` option to customize Date serialization (#159)
+- [Fix] ensure `utils.merge` handles merging two arrays
+- [Refactor] only constructors should be capitalized
+- [Refactor] capitalized var names are for constructors only
+- [Refactor] avoid using a sparse array
+- [Robustness] `formats`: cache `String#replace`
+- [Dev Deps] update `browserify`, `eslint`, `@ljharb/eslint-config`; add `safe-publish-latest`
+- [Tests] up to `node` `v6.8`, `v4.6`; improve test matrix
+- [Tests] flesh out arrayLimit/arrayFormat tests (#107)
+- [Tests] skip Object.create tests when null objects are not available
+- [Tests] Turn on eslint for test files (#175)
+
+## **6.2.4**
+- [Fix] `parse`: ignore `__proto__` keys (#428)
+- [Fix] `utils.merge`: avoid a crash with a null target and an array source
+- [Fix] `utils.merge`: avoid a crash with a null target and a truthy non-array source
+- [Fix] `utils`: `merge`: fix crash when `source` is a truthy primitive & no options are provided
+- [Fix] when `parseArrays` is false, properly handle keys ending in `[]`
+- [Robustness] `stringify`: avoid relying on a global `undefined` (#427)
+- [Refactor] use cached `Array.isArray`
+- [Docs] Clarify the need for "arrayLimit" option
+- [meta] fix README.md (#399)
+- [meta] Clean up license text so it’s properly detected as BSD-3-Clause
+- [meta] add FUNDING.yml
+- [actions] backport actions from main
+- [Tests] use `safer-buffer` instead of `Buffer` constructor
+- [Tests] remove nonexistent tape option
+- [Dev Deps] backport from main
+
+## **6.2.3**
+- [Fix] follow `allowPrototypes` option during merge (#201, #200)
+- [Fix] chmod a-x
+- [Fix] support keys starting with brackets (#202, #200)
+- [Tests] up to `node` `v7.7`, `v6.10`,` v4.8`; disable osx builds since they block linux builds
+
+## **6.2.2**
+- [Fix] ensure that `allowPrototypes: false` does not ever shadow Object.prototype properties
+
+## **6.2.1**
+- [Fix] ensure `key[]=x&key[]&key[]=y` results in 3, not 2, values
+- [Refactor] Be explicit and use `Object.prototype.hasOwnProperty.call`
+- [Tests] remove `parallelshell` since it does not reliably report failures
+- [Tests] up to `node` `v6.3`, `v5.12`
+- [Dev Deps] update `tape`, `eslint`, `@ljharb/eslint-config`, `qs-iconv`
+
+## [**6.2.0**](https://github.com/ljharb/qs/issues?milestone=36&state=closed)
+- [New] pass Buffers to the encoder/decoder directly (#161)
+- [New] add "encoder" and "decoder" options, for custom param encoding/decoding (#160)
+- [Fix] fix compacting of nested sparse arrays (#150)
+
+## **6.1.2**
+- [Fix] follow `allowPrototypes` option during merge (#201, #200)
+- [Fix] chmod a-x
+- [Fix] support keys starting with brackets (#202, #200)
+- [Tests] up to `node` `v7.7`, `v6.10`,` v4.8`; disable osx builds since they block linux builds
+
+## **6.1.1**
+- [Fix] ensure that `allowPrototypes: false` does not ever shadow Object.prototype properties
+
+## [**6.1.0**](https://github.com/ljharb/qs/issues?milestone=35&state=closed)
+- [New] allowDots option for `stringify` (#151)
+- [Fix] "sort" option should work at a depth of 3 or more (#151)
+- [Fix] Restore `dist` directory; will be removed in v7 (#148)
+
+## **6.0.4**
+- [Fix] follow `allowPrototypes` option during merge (#201, #200)
+- [Fix] chmod a-x
+- [Fix] support keys starting with brackets (#202, #200)
+- [Tests] up to `node` `v7.7`, `v6.10`,` v4.8`; disable osx builds since they block linux builds
+
+## **6.0.3**
+- [Fix] ensure that `allowPrototypes: false` does not ever shadow Object.prototype properties
+- [Fix] Restore `dist` directory; will be removed in v7 (#148)
+
+## [**6.0.2**](https://github.com/ljharb/qs/issues?milestone=33&state=closed)
+- Revert ES6 requirement and restore support for node down to v0.8.
+
+## [**6.0.1**](https://github.com/ljharb/qs/issues?milestone=32&state=closed)
+- [**#127**](https://github.com/ljharb/qs/pull/127) Fix engines definition in package.json
+
+## [**6.0.0**](https://github.com/ljharb/qs/issues?milestone=31&state=closed)
+- [**#124**](https://github.com/ljharb/qs/issues/124) Use ES6 and drop support for node < v4
+
+## **5.2.1**
+- [Fix] ensure `key[]=x&key[]&key[]=y` results in 3, not 2, values
+
+## [**5.2.0**](https://github.com/ljharb/qs/issues?milestone=30&state=closed)
+- [**#64**](https://github.com/ljharb/qs/issues/64) Add option to sort object keys in the query string
+
+## [**5.1.0**](https://github.com/ljharb/qs/issues?milestone=29&state=closed)
+- [**#117**](https://github.com/ljharb/qs/issues/117) make URI encoding stringified results optional
+- [**#106**](https://github.com/ljharb/qs/issues/106) Add flag `skipNulls` to optionally skip null values in stringify
+
+## [**5.0.0**](https://github.com/ljharb/qs/issues?milestone=28&state=closed)
+- [**#114**](https://github.com/ljharb/qs/issues/114) default allowDots to false
+- [**#100**](https://github.com/ljharb/qs/issues/100) include dist to npm
+
+## [**4.0.0**](https://github.com/ljharb/qs/issues?milestone=26&state=closed)
+- [**#98**](https://github.com/ljharb/qs/issues/98) make returning plain objects and allowing prototype overwriting properties optional
+
+## [**3.1.0**](https://github.com/ljharb/qs/issues?milestone=24&state=closed)
+- [**#89**](https://github.com/ljharb/qs/issues/89) Add option to disable "Transform dot notation to bracket notation"
+
+## [**3.0.0**](https://github.com/ljharb/qs/issues?milestone=23&state=closed)
+- [**#80**](https://github.com/ljharb/qs/issues/80) qs.parse silently drops properties
+- [**#77**](https://github.com/ljharb/qs/issues/77) Perf boost
+- [**#60**](https://github.com/ljharb/qs/issues/60) Add explicit option to disable array parsing
+- [**#74**](https://github.com/ljharb/qs/issues/74) Bad parse when turning array into object
+- [**#81**](https://github.com/ljharb/qs/issues/81) Add a `filter` option
+- [**#68**](https://github.com/ljharb/qs/issues/68) Fixed issue with recursion and passing strings into objects.
+- [**#66**](https://github.com/ljharb/qs/issues/66) Add mixed array and object dot notation support Closes: #47
+- [**#76**](https://github.com/ljharb/qs/issues/76) RFC 3986
+- [**#85**](https://github.com/ljharb/qs/issues/85) No equal sign
+- [**#84**](https://github.com/ljharb/qs/issues/84) update license attribute
+
+## [**2.4.1**](https://github.com/ljharb/qs/issues?milestone=20&state=closed)
+- [**#73**](https://github.com/ljharb/qs/issues/73) Property 'hasOwnProperty' of object #<Object> is not a function
+
+## [**2.4.0**](https://github.com/ljharb/qs/issues?milestone=19&state=closed)
+- [**#70**](https://github.com/ljharb/qs/issues/70) Add arrayFormat option
+
+## [**2.3.3**](https://github.com/ljharb/qs/issues?milestone=18&state=closed)
+- [**#59**](https://github.com/ljharb/qs/issues/59) make sure array indexes are >= 0, closes #57
+- [**#58**](https://github.com/ljharb/qs/issues/58) make qs usable for browser loader
+
+## [**2.3.2**](https://github.com/ljharb/qs/issues?milestone=17&state=closed)
+- [**#55**](https://github.com/ljharb/qs/issues/55) allow merging a string into an object
+
+## [**2.3.1**](https://github.com/ljharb/qs/issues?milestone=16&state=closed)
+- [**#52**](https://github.com/ljharb/qs/issues/52) Return "undefined" and "false" instead of throwing "TypeError".
+
+## [**2.3.0**](https://github.com/ljharb/qs/issues?milestone=15&state=closed)
+- [**#50**](https://github.com/ljharb/qs/issues/50) add option to omit array indices, closes #46
+
+## [**2.2.5**](https://github.com/ljharb/qs/issues?milestone=14&state=closed)
+- [**#39**](https://github.com/ljharb/qs/issues/39) Is there an alternative to Buffer.isBuffer?
+- [**#49**](https://github.com/ljharb/qs/issues/49) refactor utils.merge, fixes #45
+- [**#41**](https://github.com/ljharb/qs/issues/41) avoid browserifying Buffer, for #39
+
+## [**2.2.4**](https://github.com/ljharb/qs/issues?milestone=13&state=closed)
+- [**#38**](https://github.com/ljharb/qs/issues/38) how to handle object keys beginning with a number
+
+## [**2.2.3**](https://github.com/ljharb/qs/issues?milestone=12&state=closed)
+- [**#37**](https://github.com/ljharb/qs/issues/37) parser discards first empty value in array
+- [**#36**](https://github.com/ljharb/qs/issues/36) Update to lab 4.x
+
+## [**2.2.2**](https://github.com/ljharb/qs/issues?milestone=11&state=closed)
+- [**#33**](https://github.com/ljharb/qs/issues/33) Error when plain object in a value
+- [**#34**](https://github.com/ljharb/qs/issues/34) use Object.prototype.hasOwnProperty.call instead of obj.hasOwnProperty
+- [**#24**](https://github.com/ljharb/qs/issues/24) Changelog? Semver?
+
+## [**2.2.1**](https://github.com/ljharb/qs/issues?milestone=10&state=closed)
+- [**#32**](https://github.com/ljharb/qs/issues/32) account for circular references properly, closes #31
+- [**#31**](https://github.com/ljharb/qs/issues/31) qs.parse stackoverflow on circular objects
+
+## [**2.2.0**](https://github.com/ljharb/qs/issues?milestone=9&state=closed)
+- [**#26**](https://github.com/ljharb/qs/issues/26) Don't use Buffer global if it's not present
+- [**#30**](https://github.com/ljharb/qs/issues/30) Bug when merging non-object values into arrays
+- [**#29**](https://github.com/ljharb/qs/issues/29) Don't call Utils.clone at the top of Utils.merge
+- [**#23**](https://github.com/ljharb/qs/issues/23) Ability to not limit parameters?
+
+## [**2.1.0**](https://github.com/ljharb/qs/issues?milestone=8&state=closed)
+- [**#22**](https://github.com/ljharb/qs/issues/22) Enable using a RegExp as delimiter
+
+## [**2.0.0**](https://github.com/ljharb/qs/issues?milestone=7&state=closed)
+- [**#18**](https://github.com/ljharb/qs/issues/18) Why is there arrayLimit?
+- [**#20**](https://github.com/ljharb/qs/issues/20) Configurable parametersLimit
+- [**#21**](https://github.com/ljharb/qs/issues/21) make all limits optional, for #18, for #20
+
+## [**1.2.2**](https://github.com/ljharb/qs/issues?milestone=6&state=closed)
+- [**#19**](https://github.com/ljharb/qs/issues/19) Don't overwrite null values
+
+## [**1.2.1**](https://github.com/ljharb/qs/issues?milestone=5&state=closed)
+- [**#16**](https://github.com/ljharb/qs/issues/16) ignore non-string delimiters
+- [**#15**](https://github.com/ljharb/qs/issues/15) Close code block
+
+## [**1.2.0**](https://github.com/ljharb/qs/issues?milestone=4&state=closed)
+- [**#12**](https://github.com/ljharb/qs/issues/12) Add optional delim argument
+- [**#13**](https://github.com/ljharb/qs/issues/13) fix #11: flattened keys in array are now correctly parsed
+
+## [**1.1.0**](https://github.com/ljharb/qs/issues?milestone=3&state=closed)
+- [**#7**](https://github.com/ljharb/qs/issues/7) Empty values of a POST array disappear after being submitted
+- [**#9**](https://github.com/ljharb/qs/issues/9) Should not omit equals signs (=) when value is null
+- [**#6**](https://github.com/ljharb/qs/issues/6) Minor grammar fix in README
+
+## [**1.0.2**](https://github.com/ljharb/qs/issues?milestone=2&state=closed)
+- [**#5**](https://github.com/ljharb/qs/issues/5) array holes incorrectly copied into object on large index
diff --git a/server/node_modules/qs/LICENSE.md b/server/node_modules/qs/LICENSE.md
new file mode 100644
index 0000000..fecf6b6
--- /dev/null
+++ b/server/node_modules/qs/LICENSE.md
@@ -0,0 +1,29 @@
+BSD 3-Clause License
+
+Copyright (c) 2014, Nathan LaFreniere and other [contributors](https://github.com/ljharb/qs/graphs/contributors)
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/server/node_modules/qs/README.md b/server/node_modules/qs/README.md
new file mode 100644
index 0000000..22c411d
--- /dev/null
+++ b/server/node_modules/qs/README.md
@@ -0,0 +1,733 @@
+<p align="center">
+    <img alt="qs" src="./logos/banner_default.png" width="800" />
+</p>
+
+# qs <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+[![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/9058/badge)](https://bestpractices.coreinfrastructure.org/projects/9058)
+
+[![npm badge][npm-badge-png]][package-url]
+
+A querystring parsing and stringifying library with some added security.
+
+Lead Maintainer: [Jordan Harband](https://github.com/ljharb)
+
+The **qs** module was originally created and maintained by [TJ Holowaychuk](https://github.com/visionmedia/node-querystring).
+
+## Usage
+
+```javascript
+var qs = require('qs');
+var assert = require('assert');
+
+var obj = qs.parse('a=c');
+assert.deepEqual(obj, { a: 'c' });
+
+var str = qs.stringify(obj);
+assert.equal(str, 'a=c');
+```
+
+### Parsing Objects
+
+[](#preventEval)
+```javascript
+qs.parse(string, [options]);
+```
+
+**qs** allows you to create nested objects within your query strings, by surrounding the name of sub-keys with square brackets `[]`.
+For example, the string `'foo[bar]=baz'` converts to:
+
+```javascript
+assert.deepEqual(qs.parse('foo[bar]=baz'), {
+    foo: {
+        bar: 'baz'
+    }
+});
+```
+
+When using the `plainObjects` option the parsed value is returned as a null object, created via `{ __proto__: null }` and as such you should be aware that prototype methods will not exist on it and a user may set those names to whatever value they like:
+
+```javascript
+var nullObject = qs.parse('a[hasOwnProperty]=b', { plainObjects: true });
+assert.deepEqual(nullObject, { a: { hasOwnProperty: 'b' } });
+```
+
+By default parameters that would overwrite properties on the object prototype are ignored, if you wish to keep the data from those fields either use `plainObjects` as mentioned above, or set `allowPrototypes` to `true` which will allow user input to overwrite those properties.
+*WARNING* It is generally a bad idea to enable this option as it can cause problems when attempting to use the properties that have been overwritten.
+Always be careful with this option.
+
+```javascript
+var protoObject = qs.parse('a[hasOwnProperty]=b', { allowPrototypes: true });
+assert.deepEqual(protoObject, { a: { hasOwnProperty: 'b' } });
+```
+
+URI encoded strings work too:
+
+```javascript
+assert.deepEqual(qs.parse('a%5Bb%5D=c'), {
+    a: { b: 'c' }
+});
+```
+
+You can also nest your objects, like `'foo[bar][baz]=foobarbaz'`:
+
+```javascript
+assert.deepEqual(qs.parse('foo[bar][baz]=foobarbaz'), {
+    foo: {
+        bar: {
+            baz: 'foobarbaz'
+        }
+    }
+});
+```
+
+By default, when nesting objects **qs** will only parse up to 5 children deep.
+This means if you attempt to parse a string like `'a[b][c][d][e][f][g][h][i]=j'` your resulting object will be:
+
+```javascript
+var expected = {
+    a: {
+        b: {
+            c: {
+                d: {
+                    e: {
+                        f: {
+                            '[g][h][i]': 'j'
+                        }
+                    }
+                }
+            }
+        }
+    }
+};
+var string = 'a[b][c][d][e][f][g][h][i]=j';
+assert.deepEqual(qs.parse(string), expected);
+```
+
+This depth can be overridden by passing a `depth` option to `qs.parse(string, [options])`:
+
+```javascript
+var deep = qs.parse('a[b][c][d][e][f][g][h][i]=j', { depth: 1 });
+assert.deepEqual(deep, { a: { b: { '[c][d][e][f][g][h][i]': 'j' } } });
+```
+
+You can configure **qs** to throw an error when parsing nested input beyond this depth using the `strictDepth` option (defaulted to false):
+
+```javascript
+try {
+    qs.parse('a[b][c][d][e][f][g][h][i]=j', { depth: 1, strictDepth: true });
+} catch (err) {
+    assert(err instanceof RangeError);
+    assert.strictEqual(err.message, 'Input depth exceeded depth option of 1 and strictDepth is true');
+}
+```
+
+The depth limit helps mitigate abuse when **qs** is used to parse user input, and it is recommended to keep it a reasonably small number. The strictDepth option adds a layer of protection by throwing an error when the limit is exceeded, allowing you to catch and handle such cases.
+
+For similar reasons, by default **qs** will only parse up to 1000 parameters. This can be overridden by passing a `parameterLimit` option:
+
+```javascript
+var limited = qs.parse('a=b&c=d', { parameterLimit: 1 });
+assert.deepEqual(limited, { a: 'b' });
+```
+
+If you want an error to be thrown whenever the a limit is exceeded (eg, `parameterLimit`, `arrayLimit`), set the `throwOnLimitExceeded` option to `true`. This option will generate a descriptive error if the query string exceeds a configured limit.
+```javascript
+try {
+    qs.parse('a=1&b=2&c=3&d=4', { parameterLimit: 3, throwOnLimitExceeded: true });
+} catch (err) {
+    assert(err instanceof Error);
+    assert.strictEqual(err.message, 'Parameter limit exceeded. Only 3 parameters allowed.');
+}
+```
+
+When `throwOnLimitExceeded` is set to `false` (default), **qs** will parse up to the specified `parameterLimit` and ignore the rest without throwing an error.
+
+To bypass the leading question mark, use `ignoreQueryPrefix`:
+
+```javascript
+var prefixed = qs.parse('?a=b&c=d', { ignoreQueryPrefix: true });
+assert.deepEqual(prefixed, { a: 'b', c: 'd' });
+```
+
+An optional delimiter can also be passed:
+
+```javascript
+var delimited = qs.parse('a=b;c=d', { delimiter: ';' });
+assert.deepEqual(delimited, { a: 'b', c: 'd' });
+```
+
+Delimiters can be a regular expression too:
+
+```javascript
+var regexed = qs.parse('a=b;c=d,e=f', { delimiter: /[;,]/ });
+assert.deepEqual(regexed, { a: 'b', c: 'd', e: 'f' });
+```
+
+Option `allowDots` can be used to enable dot notation:
+
+```javascript
+var withDots = qs.parse('a.b=c', { allowDots: true });
+assert.deepEqual(withDots, { a: { b: 'c' } });
+```
+
+Option `decodeDotInKeys` can be used to decode dots in keys
+Note: it implies `allowDots`, so `parse` will error if you set `decodeDotInKeys` to `true`, and `allowDots` to `false`.
+
+```javascript
+var withDots = qs.parse('name%252Eobj.first=John&name%252Eobj.last=Doe', { decodeDotInKeys: true });
+assert.deepEqual(withDots, { 'name.obj': { first: 'John', last: 'Doe' }});
+```
+
+Option `allowEmptyArrays` can be used to allowing empty array values in object
+```javascript
+var withEmptyArrays = qs.parse('foo[]&bar=baz', { allowEmptyArrays: true });
+assert.deepEqual(withEmptyArrays, { foo: [], bar: 'baz' });
+```
+
+Option `duplicates` can be used to change the behavior when duplicate keys are encountered
+```javascript
+assert.deepEqual(qs.parse('foo=bar&foo=baz'), { foo: ['bar', 'baz'] });
+assert.deepEqual(qs.parse('foo=bar&foo=baz', { duplicates: 'combine' }), { foo: ['bar', 'baz'] });
+assert.deepEqual(qs.parse('foo=bar&foo=baz', { duplicates: 'first' }), { foo: 'bar' });
+assert.deepEqual(qs.parse('foo=bar&foo=baz', { duplicates: 'last' }), { foo: 'baz' });
+```
+
+If you have to deal with legacy browsers or services, there's also support for decoding percent-encoded octets as iso-8859-1:
+
+```javascript
+var oldCharset = qs.parse('a=%A7', { charset: 'iso-8859-1' });
+assert.deepEqual(oldCharset, { a: '§' });
+```
+
+Some services add an initial `utf8=✓` value to forms so that old Internet Explorer versions are more likely to submit the form as utf-8.
+Additionally, the server can check the value against wrong encodings of the checkmark character and detect that a query string or `application/x-www-form-urlencoded` body was *not* sent as utf-8, eg. if the form had an `accept-charset` parameter or the containing page had a different character set.
+
+**qs** supports this mechanism via the `charsetSentinel` option.
+If specified, the `utf8` parameter will be omitted from the returned object.
+It will be used to switch to `iso-8859-1`/`utf-8` mode depending on how the checkmark is encoded.
+
+**Important**: When you specify both the `charset` option and the `charsetSentinel` option, the `charset` will be overridden when the request contains a `utf8` parameter from which the actual charset can be deduced.
+In that sense the `charset` will behave as the default charset rather than the authoritative charset.
+
+```javascript
+var detectedAsUtf8 = qs.parse('utf8=%E2%9C%93&a=%C3%B8', {
+    charset: 'iso-8859-1',
+    charsetSentinel: true
+});
+assert.deepEqual(detectedAsUtf8, { a: 'ø' });
+
+// Browsers encode the checkmark as ✓ when submitting as iso-8859-1:
+var detectedAsIso8859_1 = qs.parse('utf8=%26%2310003%3B&a=%F8', {
+    charset: 'utf-8',
+    charsetSentinel: true
+});
+assert.deepEqual(detectedAsIso8859_1, { a: 'ø' });
+```
+
+If you want to decode the `&#...;` syntax to the actual character, you can specify the `interpretNumericEntities` option as well:
+
+```javascript
+var detectedAsIso8859_1 = qs.parse('a=%26%239786%3B', {
+    charset: 'iso-8859-1',
+    interpretNumericEntities: true
+});
+assert.deepEqual(detectedAsIso8859_1, { a: '☺' });
+```
+
+It also works when the charset has been detected in `charsetSentinel` mode.
+
+### Parsing Arrays
+
+**qs** can also parse arrays using a similar `[]` notation:
+
+```javascript
+var withArray = qs.parse('a[]=b&a[]=c');
+assert.deepEqual(withArray, { a: ['b', 'c'] });
+```
+
+You may specify an index as well:
+
+```javascript
+var withIndexes = qs.parse('a[1]=c&a[0]=b');
+assert.deepEqual(withIndexes, { a: ['b', 'c'] });
+```
+
+Note that the only difference between an index in an array and a key in an object is that the value between the brackets must be a number to create an array.
+When creating arrays with specific indices, **qs** will compact a sparse array to only the existing values preserving their order:
+
+```javascript
+var noSparse = qs.parse('a[1]=b&a[15]=c');
+assert.deepEqual(noSparse, { a: ['b', 'c'] });
+```
+
+You may also use `allowSparse` option to parse sparse arrays:
+
+```javascript
+var sparseArray = qs.parse('a[1]=2&a[3]=5', { allowSparse: true });
+assert.deepEqual(sparseArray, { a: [, '2', , '5'] });
+```
+
+Note that an empty string is also a value, and will be preserved:
+
+```javascript
+var withEmptyString = qs.parse('a[]=&a[]=b');
+assert.deepEqual(withEmptyString, { a: ['', 'b'] });
+
+var withIndexedEmptyString = qs.parse('a[0]=b&a[1]=&a[2]=c');
+assert.deepEqual(withIndexedEmptyString, { a: ['b', '', 'c'] });
+```
+
+**qs** will also limit specifying indices in an array to a maximum index of `20`.
+Any array members with an index of greater than `20` will instead be converted to an object with the index as the key.
+This is needed to handle cases when someone sent, for example, `a[999999999]` and it will take significant time to iterate over this huge array.
+
+```javascript
+var withMaxIndex = qs.parse('a[100]=b');
+assert.deepEqual(withMaxIndex, { a: { '100': 'b' } });
+```
+
+This limit can be overridden by passing an `arrayLimit` option:
+
+```javascript
+var withArrayLimit = qs.parse('a[1]=b', { arrayLimit: 0 });
+assert.deepEqual(withArrayLimit, { a: { '1': 'b' } });
+```
+
+If you want to throw an error whenever the array limit is exceeded, set the `throwOnLimitExceeded` option to `true`. This option will generate a descriptive error if the query string exceeds a configured limit.
+```javascript
+try {
+    qs.parse('a[1]=b', { arrayLimit: 0, throwOnLimitExceeded: true });
+} catch (err) {
+    assert(err instanceof Error);
+    assert.strictEqual(err.message, 'Array limit exceeded. Only 0 elements allowed in an array.');
+}
+```
+
+When `throwOnLimitExceeded` is set to `false` (default), **qs** will parse up to the specified `arrayLimit` and if the limit is exceeded, the array will instead be converted to an object with the index as the key
+
+To disable array parsing entirely, set `parseArrays` to `false`.
+
+```javascript
+var noParsingArrays = qs.parse('a[]=b', { parseArrays: false });
+assert.deepEqual(noParsingArrays, { a: { '0': 'b' } });
+```
+
+If you mix notations, **qs** will merge the two items into an object:
+
+```javascript
+var mixedNotation = qs.parse('a[0]=b&a[b]=c');
+assert.deepEqual(mixedNotation, { a: { '0': 'b', b: 'c' } });
+```
+
+You can also create arrays of objects:
+
+```javascript
+var arraysOfObjects = qs.parse('a[][b]=c');
+assert.deepEqual(arraysOfObjects, { a: [{ b: 'c' }] });
+```
+
+Some people use comma to join array, **qs** can parse it:
+```javascript
+var arraysOfObjects = qs.parse('a=b,c', { comma: true })
+assert.deepEqual(arraysOfObjects, { a: ['b', 'c'] })
+```
+(_this cannot convert nested objects, such as `a={b:1},{c:d}`_)
+
+### Parsing primitive/scalar values (numbers, booleans, null, etc)
+
+By default, all values are parsed as strings.
+This behavior will not change and is explained in [issue #91](https://github.com/ljharb/qs/issues/91).
+
+```javascript
+var primitiveValues = qs.parse('a=15&b=true&c=null');
+assert.deepEqual(primitiveValues, { a: '15', b: 'true', c: 'null' });
+```
+
+If you wish to auto-convert values which look like numbers, booleans, and other values into their primitive counterparts, you can use the [query-types Express JS middleware](https://github.com/xpepermint/query-types) which will auto-convert all request query parameters.
+
+### Stringifying
+
+[](#preventEval)
+```javascript
+qs.stringify(object, [options]);
+```
+
+When stringifying, **qs** by default URI encodes output. Objects are stringified as you would expect:
+
+```javascript
+assert.equal(qs.stringify({ a: 'b' }), 'a=b');
+assert.equal(qs.stringify({ a: { b: 'c' } }), 'a%5Bb%5D=c');
+```
+
+This encoding can be disabled by setting the `encode` option to `false`:
+
+```javascript
+var unencoded = qs.stringify({ a: { b: 'c' } }, { encode: false });
+assert.equal(unencoded, 'a[b]=c');
+```
+
+Encoding can be disabled for keys by setting the `encodeValuesOnly` option to `true`:
+```javascript
+var encodedValues = qs.stringify(
+    { a: 'b', c: ['d', 'e=f'], f: [['g'], ['h']] },
+    { encodeValuesOnly: true }
+);
+assert.equal(encodedValues,'a=b&c[0]=d&c[1]=e%3Df&f[0][0]=g&f[1][0]=h');
+```
+
+This encoding can also be replaced by a custom encoding method set as `encoder` option:
+
+```javascript
+var encoded = qs.stringify({ a: { b: 'c' } }, { encoder: function (str) {
+    // Passed in values `a`, `b`, `c`
+    return // Return encoded string
+}})
+```
+
+_(Note: the `encoder` option does not apply if `encode` is `false`)_
+
+Analogue to the `encoder` there is a `decoder` option for `parse` to override decoding of properties and values:
+
+```javascript
+var decoded = qs.parse('x=z', { decoder: function (str) {
+    // Passed in values `x`, `z`
+    return // Return decoded string
+}})
+```
+
+You can encode keys and values using different logic by using the type argument provided to the encoder:
+
+```javascript
+var encoded = qs.stringify({ a: { b: 'c' } }, { encoder: function (str, defaultEncoder, charset, type) {
+    if (type === 'key') {
+        return // Encoded key
+    } else if (type === 'value') {
+        return // Encoded value
+    }
+}})
+```
+
+The type argument is also provided to the decoder:
+
+```javascript
+var decoded = qs.parse('x=z', { decoder: function (str, defaultDecoder, charset, type) {
+    if (type === 'key') {
+        return // Decoded key
+    } else if (type === 'value') {
+        return // Decoded value
+    }
+}})
+```
+
+Examples beyond this point will be shown as though the output is not URI encoded for clarity.
+Please note that the return values in these cases *will* be URI encoded during real usage.
+
+When arrays are stringified, they follow the `arrayFormat` option, which defaults to `indices`:
+
+```javascript
+qs.stringify({ a: ['b', 'c', 'd'] });
+// 'a[0]=b&a[1]=c&a[2]=d'
+```
+
+You may override this by setting the `indices` option to `false`, or to be more explicit, the `arrayFormat` option to `repeat`:
+
+```javascript
+qs.stringify({ a: ['b', 'c', 'd'] }, { indices: false });
+// 'a=b&a=c&a=d'
+```
+
+You may use the `arrayFormat` option to specify the format of the output array:
+
+```javascript
+qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'indices' })
+// 'a[0]=b&a[1]=c'
+qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'brackets' })
+// 'a[]=b&a[]=c'
+qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'repeat' })
+// 'a=b&a=c'
+qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'comma' })
+// 'a=b,c'
+```
+
+Note: when using `arrayFormat` set to `'comma'`, you can also pass the `commaRoundTrip` option set to `true` or `false`, to append `[]` on single-item arrays, so that they can round trip through a parse.
+
+When objects are stringified, by default they use bracket notation:
+
+```javascript
+qs.stringify({ a: { b: { c: 'd', e: 'f' } } });
+// 'a[b][c]=d&a[b][e]=f'
+```
+
+You may override this to use dot notation by setting the `allowDots` option to `true`:
+
+```javascript
+qs.stringify({ a: { b: { c: 'd', e: 'f' } } }, { allowDots: true });
+// 'a.b.c=d&a.b.e=f'
+```
+
+You may encode the dot notation in the keys of object with option `encodeDotInKeys` by setting it to `true`:
+Note: it implies `allowDots`, so `stringify` will error if you set `decodeDotInKeys` to `true`, and `allowDots` to `false`.
+Caveat: when `encodeValuesOnly` is `true` as well as `encodeDotInKeys`, only dots in keys and nothing else will be encoded.
+```javascript
+qs.stringify({ "name.obj": { "first": "John", "last": "Doe" } }, { allowDots: true, encodeDotInKeys: true })
+// 'name%252Eobj.first=John&name%252Eobj.last=Doe'
+```
+
+You may allow empty array values by setting the `allowEmptyArrays` option to `true`:
+```javascript
+qs.stringify({ foo: [], bar: 'baz' }, { allowEmptyArrays: true });
+// 'foo[]&bar=baz'
+```
+
+Empty strings and null values will omit the value, but the equals sign (=) remains in place:
+
+```javascript
+assert.equal(qs.stringify({ a: '' }), 'a=');
+```
+
+Key with no values (such as an empty object or array) will return nothing:
+
+```javascript
+assert.equal(qs.stringify({ a: [] }), '');
+assert.equal(qs.stringify({ a: {} }), '');
+assert.equal(qs.stringify({ a: [{}] }), '');
+assert.equal(qs.stringify({ a: { b: []} }), '');
+assert.equal(qs.stringify({ a: { b: {}} }), '');
+```
+
+Properties that are set to `undefined` will be omitted entirely:
+
+```javascript
+assert.equal(qs.stringify({ a: null, b: undefined }), 'a=');
+```
+
+The query string may optionally be prepended with a question mark:
+
+```javascript
+assert.equal(qs.stringify({ a: 'b', c: 'd' }, { addQueryPrefix: true }), '?a=b&c=d');
+```
+
+The delimiter may be overridden with stringify as well:
+
+```javascript
+assert.equal(qs.stringify({ a: 'b', c: 'd' }, { delimiter: ';' }), 'a=b;c=d');
+```
+
+If you only want to override the serialization of `Date` objects, you can provide a `serializeDate` option:
+
+```javascript
+var date = new Date(7);
+assert.equal(qs.stringify({ a: date }), 'a=1970-01-01T00:00:00.007Z'.replace(/:/g, '%3A'));
+assert.equal(
+    qs.stringify({ a: date }, { serializeDate: function (d) { return d.getTime(); } }),
+    'a=7'
+);
+```
+
+You may use the `sort` option to affect the order of parameter keys:
+
+```javascript
+function alphabeticalSort(a, b) {
+    return a.localeCompare(b);
+}
+assert.equal(qs.stringify({ a: 'c', z: 'y', b : 'f' }, { sort: alphabeticalSort }), 'a=c&b=f&z=y');
+```
+
+Finally, you can use the `filter` option to restrict which keys will be included in the stringified output.
+If you pass a function, it will be called for each key to obtain the replacement value.
+Otherwise, if you pass an array, it will be used to select properties and array indices for stringification:
+
+```javascript
+function filterFunc(prefix, value) {
+    if (prefix == 'b') {
+        // Return an `undefined` value to omit a property.
+        return;
+    }
+    if (prefix == 'e[f]') {
+        return value.getTime();
+    }
+    if (prefix == 'e[g][0]') {
+        return value * 2;
+    }
+    return value;
+}
+qs.stringify({ a: 'b', c: 'd', e: { f: new Date(123), g: [2] } }, { filter: filterFunc });
+// 'a=b&c=d&e[f]=123&e[g][0]=4'
+qs.stringify({ a: 'b', c: 'd', e: 'f' }, { filter: ['a', 'e'] });
+// 'a=b&e=f'
+qs.stringify({ a: ['b', 'c', 'd'], e: 'f' }, { filter: ['a', 0, 2] });
+// 'a[0]=b&a[2]=d'
+```
+
+You could also use `filter` to inject custom serialization for user defined types.
+Consider you're working with some api that expects query strings of the format for ranges:
+
+```
+https://domain.com/endpoint?range=30...70
+```
+
+For which you model as:
+
+```javascript
+class Range {
+    constructor(from, to) {
+        this.from = from;
+        this.to = to;
+    }
+}
+```
+
+You could _inject_ a custom serializer to handle values of this type:
+
+```javascript
+qs.stringify(
+    {
+        range: new Range(30, 70),
+    },
+    {
+        filter: (prefix, value) => {
+            if (value instanceof Range) {
+                return `${value.from}...${value.to}`;
+            }
+            // serialize the usual way
+            return value;
+        },
+    }
+);
+// range=30...70
+```
+
+### Handling of `null` values
+
+By default, `null` values are treated like empty strings:
+
+```javascript
+var withNull = qs.stringify({ a: null, b: '' });
+assert.equal(withNull, 'a=&b=');
+```
+
+Parsing does not distinguish between parameters with and without equal signs.
+Both are converted to empty strings.
+
+```javascript
+var equalsInsensitive = qs.parse('a&b=');
+assert.deepEqual(equalsInsensitive, { a: '', b: '' });
+```
+
+To distinguish between `null` values and empty strings use the `strictNullHandling` flag. In the result string the `null`
+values have no `=` sign:
+
+```javascript
+var strictNull = qs.stringify({ a: null, b: '' }, { strictNullHandling: true });
+assert.equal(strictNull, 'a&b=');
+```
+
+To parse values without `=` back to `null` use the `strictNullHandling` flag:
+
+```javascript
+var parsedStrictNull = qs.parse('a&b=', { strictNullHandling: true });
+assert.deepEqual(parsedStrictNull, { a: null, b: '' });
+```
+
+To completely skip rendering keys with `null` values, use the `skipNulls` flag:
+
+```javascript
+var nullsSkipped = qs.stringify({ a: 'b', c: null}, { skipNulls: true });
+assert.equal(nullsSkipped, 'a=b');
+```
+
+If you're communicating with legacy systems, you can switch to `iso-8859-1` using the `charset` option:
+
+```javascript
+var iso = qs.stringify({ æ: 'æ' }, { charset: 'iso-8859-1' });
+assert.equal(iso, '%E6=%E6');
+```
+
+Characters that don't exist in `iso-8859-1` will be converted to numeric entities, similar to what browsers do:
+
+```javascript
+var numeric = qs.stringify({ a: '☺' }, { charset: 'iso-8859-1' });
+assert.equal(numeric, 'a=%26%239786%3B');
+```
+
+You can use the `charsetSentinel` option to announce the character by including an `utf8=✓` parameter with the proper encoding if the checkmark, similar to what Ruby on Rails and others do when submitting forms.
+
+```javascript
+var sentinel = qs.stringify({ a: '☺' }, { charsetSentinel: true });
+assert.equal(sentinel, 'utf8=%E2%9C%93&a=%E2%98%BA');
+
+var isoSentinel = qs.stringify({ a: 'æ' }, { charsetSentinel: true, charset: 'iso-8859-1' });
+assert.equal(isoSentinel, 'utf8=%26%2310003%3B&a=%E6');
+```
+
+### Dealing with special character sets
+
+By default the encoding and decoding of characters is done in `utf-8`, and `iso-8859-1` support is also built in via the `charset` parameter.
+
+If you wish to encode querystrings to a different character set (i.e.
+[Shift JIS](https://en.wikipedia.org/wiki/Shift_JIS)) you can use the
+[`qs-iconv`](https://github.com/martinheidegger/qs-iconv) library:
+
+```javascript
+var encoder = require('qs-iconv/encoder')('shift_jis');
+var shiftJISEncoded = qs.stringify({ a: 'こんにちは！' }, { encoder: encoder });
+assert.equal(shiftJISEncoded, 'a=%82%B1%82%F1%82%C9%82%BF%82%CD%81I');
+```
+
+This also works for decoding of query strings:
+
+```javascript
+var decoder = require('qs-iconv/decoder')('shift_jis');
+var obj = qs.parse('a=%82%B1%82%F1%82%C9%82%BF%82%CD%81I', { decoder: decoder });
+assert.deepEqual(obj, { a: 'こんにちは！' });
+```
+
+### RFC 3986 and RFC 1738 space encoding
+
+RFC3986 used as default option and encodes ' ' to *%20* which is backward compatible.
+In the same time, output can be stringified as per RFC1738 with ' ' equal to '+'.
+
+```
+assert.equal(qs.stringify({ a: 'b c' }), 'a=b%20c');
+assert.equal(qs.stringify({ a: 'b c' }, { format : 'RFC3986' }), 'a=b%20c');
+assert.equal(qs.stringify({ a: 'b c' }, { format : 'RFC1738' }), 'a=b+c');
+```
+
+## Security
+
+Please email [@ljharb](https://github.com/ljharb) or see https://tidelift.com/security if you have a potential security vulnerability to report.
+
+## qs for enterprise
+
+Available as part of the Tidelift Subscription
+
+The maintainers of qs and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications.
+Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use.
+[Learn more.](https://tidelift.com/subscription/pkg/npm-qs?utm_source=npm-qs&utm_medium=referral&utm_campaign=enterprise&utm_term=repo)
+
+[package-url]: https://npmjs.org/package/qs
+[npm-version-svg]: https://versionbadg.es/ljharb/qs.svg
+[deps-svg]: https://david-dm.org/ljharb/qs.svg
+[deps-url]: https://david-dm.org/ljharb/qs
+[dev-deps-svg]: https://david-dm.org/ljharb/qs/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/qs#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/qs.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/qs.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/qs.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=qs
+[codecov-image]: https://codecov.io/gh/ljharb/qs/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/qs/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/qs
+[actions-url]: https://github.com/ljharb/qs/actions
+
+## Acknowledgements
+
+qs logo by [NUMI](https://github.com/numi-hq/open-design):
+
+[<img src="https://raw.githubusercontent.com/numi-hq/open-design/main/assets/numi-lockup.png" alt="NUMI Logo" style="width: 200px;"/>](https://numi.tech/?ref=qs)
diff --git a/server/node_modules/qs/dist/qs.js b/server/node_modules/qs/dist/qs.js
new file mode 100644
index 0000000..2cee370
--- /dev/null
+++ b/server/node_modules/qs/dist/qs.js
@@ -0,0 +1,141 @@
+(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.Qs = f()}})(function(){var define,module,exports;return (function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r})()({1:[function(require,module,exports){
+"use strict";var replace=String.prototype.replace,percentTwenties=/%20/g,Format={RFC1738:"RFC1738",RFC3986:"RFC3986"};module.exports={default:Format.RFC3986,formatters:{RFC1738:function(e){return replace.call(e,percentTwenties,"+")},RFC3986:function(e){return String(e)}},RFC1738:Format.RFC1738,RFC3986:Format.RFC3986};
+
+},{}],2:[function(require,module,exports){
+"use strict";var stringify=require(4),parse=require(3),formats=require(1);module.exports={formats:formats,parse:parse,stringify:stringify};
+
+},{"1":1,"3":3,"4":4}],3:[function(require,module,exports){
+"use strict";var utils=require(5),has=Object.prototype.hasOwnProperty,isArray=Array.isArray,defaults={allowDots:!1,allowEmptyArrays:!1,allowPrototypes:!1,allowSparse:!1,arrayLimit:20,charset:"utf-8",charsetSentinel:!1,comma:!1,decodeDotInKeys:!1,decoder:utils.decode,delimiter:"&",depth:5,duplicates:"combine",ignoreQueryPrefix:!1,interpretNumericEntities:!1,parameterLimit:1e3,parseArrays:!0,plainObjects:!1,strictDepth:!1,strictNullHandling:!1,throwOnLimitExceeded:!1},interpretNumericEntities=function(e){return e.replace(/&#(\d+);/g,function(e,t){return String.fromCharCode(parseInt(t,10))})},parseArrayValue=function(e,t,r){if(e&&"string"==typeof e&&t.comma&&e.indexOf(",")>-1)return e.split(",");if(t.throwOnLimitExceeded&&r>=t.arrayLimit)throw new RangeError("Array limit exceeded. Only "+t.arrayLimit+" element"+(1===t.arrayLimit?"":"s")+" allowed in an array.");return e},isoSentinel="utf8=%26%2310003%3B",charsetSentinel="utf8=%E2%9C%93",parseValues=function parseQueryStringValues(e,t){var r={__proto__:null},i=t.ignoreQueryPrefix?e.replace(/^\?/,""):e;i=i.replace(/%5B/gi,"[").replace(/%5D/gi,"]");var a=t.parameterLimit===1/0?void 0:t.parameterLimit,o=i.split(t.delimiter,t.throwOnLimitExceeded?a+1:a);if(t.throwOnLimitExceeded&&o.length>a)throw new RangeError("Parameter limit exceeded. Only "+a+" parameter"+(1===a?"":"s")+" allowed.");var l,n=-1,s=t.charset;if(t.charsetSentinel)for(l=0;l<o.length;++l)0===o[l].indexOf("utf8=")&&(o[l]===charsetSentinel?s="utf-8":o[l]===isoSentinel&&(s="iso-8859-1"),n=l,l=o.length);for(l=0;l<o.length;++l)if(l!==n){var p,d,c=o[l],u=c.indexOf("]="),y=-1===u?c.indexOf("="):u+1;if(-1===y?(p=t.decoder(c,defaults.decoder,s,"key"),d=t.strictNullHandling?null:""):null!==(p=t.decoder(c.slice(0,y),defaults.decoder,s,"key"))&&(d=utils.maybeMap(parseArrayValue(c.slice(y+1),t,isArray(r[p])?r[p].length:0),function(e){return t.decoder(e,defaults.decoder,s,"value")})),d&&t.interpretNumericEntities&&"iso-8859-1"===s&&(d=interpretNumericEntities(String(d))),c.indexOf("[]=")>-1&&(d=isArray(d)?[d]:d),null!==p){var f=has.call(r,p);f&&"combine"===t.duplicates?r[p]=utils.combine(r[p],d,t.arrayLimit,t.plainObjects):f&&"last"!==t.duplicates||(r[p]=d)}}return r},parseObject=function(e,t,r,i){var a=0;if(e.length>0&&"[]"===e[e.length-1]){var o=e.slice(0,-1).join("");a=Array.isArray(t)&&t[o]?t[o].length:0}for(var l=i?t:parseArrayValue(t,r,a),n=e.length-1;n>=0;--n){var s,p=e[n];if("[]"===p&&r.parseArrays)s=utils.isOverflow(l)?l:r.allowEmptyArrays&&(""===l||r.strictNullHandling&&null===l)?[]:utils.combine([],l,r.arrayLimit,r.plainObjects);else{s=r.plainObjects?{__proto__:null}:{};var d="["===p.charAt(0)&&"]"===p.charAt(p.length-1)?p.slice(1,-1):p,c=r.decodeDotInKeys?d.replace(/%2E/g,"."):d,u=parseInt(c,10);r.parseArrays||""!==c?!isNaN(u)&&p!==c&&String(u)===c&&u>=0&&r.parseArrays&&u<=r.arrayLimit?(s=[])[u]=l:"__proto__"!==c&&(s[c]=l):s={0:l}}l=s}return l},splitKeyIntoSegments=function splitKeyIntoSegments(e,t){var r=t.allowDots?e.replace(/\.([^.[]+)/g,"[$1]"):e;if(t.depth<=0){if(!t.plainObjects&&has.call(Object.prototype,r)&&!t.allowPrototypes)return;return[r]}var i=/(\[[^[\]]*])/g,a=/(\[[^[\]]*])/.exec(r),o=a?r.slice(0,a.index):r,l=[];if(o){if(!t.plainObjects&&has.call(Object.prototype,o)&&!t.allowPrototypes)return;l.push(o)}for(var n=0;null!==(a=i.exec(r))&&n<t.depth;){n+=1;var s=a[1].slice(1,-1);if(!t.plainObjects&&has.call(Object.prototype,s)&&!t.allowPrototypes)return;l.push(a[1])}if(a){if(!0===t.strictDepth)throw new RangeError("Input depth exceeded depth option of "+t.depth+" and strictDepth is true");l.push("["+r.slice(a.index)+"]")}return l},parseKeys=function parseQueryStringKeys(e,t,r,i){if(e){var a=splitKeyIntoSegments(e,r);if(a)return parseObject(a,t,r,i)}},normalizeParseOptions=function normalizeParseOptions(e){if(!e)return defaults;if(void 0!==e.allowEmptyArrays&&"boolean"!=typeof e.allowEmptyArrays)throw new TypeError("`allowEmptyArrays` option can only be `true` or `false`, when provided");if(void 0!==e.decodeDotInKeys&&"boolean"!=typeof e.decodeDotInKeys)throw new TypeError("`decodeDotInKeys` option can only be `true` or `false`, when provided");if(null!==e.decoder&&void 0!==e.decoder&&"function"!=typeof e.decoder)throw new TypeError("Decoder has to be a function.");if(void 0!==e.charset&&"utf-8"!==e.charset&&"iso-8859-1"!==e.charset)throw new TypeError("The charset option must be either utf-8, iso-8859-1, or undefined");if(void 0!==e.throwOnLimitExceeded&&"boolean"!=typeof e.throwOnLimitExceeded)throw new TypeError("`throwOnLimitExceeded` option must be a boolean");var t=void 0===e.charset?defaults.charset:e.charset,r=void 0===e.duplicates?defaults.duplicates:e.duplicates;if("combine"!==r&&"first"!==r&&"last"!==r)throw new TypeError("The duplicates option must be either combine, first, or last");return{allowDots:void 0===e.allowDots?!0===e.decodeDotInKeys||defaults.allowDots:!!e.allowDots,allowEmptyArrays:"boolean"==typeof e.allowEmptyArrays?!!e.allowEmptyArrays:defaults.allowEmptyArrays,allowPrototypes:"boolean"==typeof e.allowPrototypes?e.allowPrototypes:defaults.allowPrototypes,allowSparse:"boolean"==typeof e.allowSparse?e.allowSparse:defaults.allowSparse,arrayLimit:"number"==typeof e.arrayLimit?e.arrayLimit:defaults.arrayLimit,charset:t,charsetSentinel:"boolean"==typeof e.charsetSentinel?e.charsetSentinel:defaults.charsetSentinel,comma:"boolean"==typeof e.comma?e.comma:defaults.comma,decodeDotInKeys:"boolean"==typeof e.decodeDotInKeys?e.decodeDotInKeys:defaults.decodeDotInKeys,decoder:"function"==typeof e.decoder?e.decoder:defaults.decoder,delimiter:"string"==typeof e.delimiter||utils.isRegExp(e.delimiter)?e.delimiter:defaults.delimiter,depth:"number"==typeof e.depth||!1===e.depth?+e.depth:defaults.depth,duplicates:r,ignoreQueryPrefix:!0===e.ignoreQueryPrefix,interpretNumericEntities:"boolean"==typeof e.interpretNumericEntities?e.interpretNumericEntities:defaults.interpretNumericEntities,parameterLimit:"number"==typeof e.parameterLimit?e.parameterLimit:defaults.parameterLimit,parseArrays:!1!==e.parseArrays,plainObjects:"boolean"==typeof e.plainObjects?e.plainObjects:defaults.plainObjects,strictDepth:"boolean"==typeof e.strictDepth?!!e.strictDepth:defaults.strictDepth,strictNullHandling:"boolean"==typeof e.strictNullHandling?e.strictNullHandling:defaults.strictNullHandling,throwOnLimitExceeded:"boolean"==typeof e.throwOnLimitExceeded&&e.throwOnLimitExceeded}};module.exports=function(e,t){var r=normalizeParseOptions(t);if(""===e||null==e)return r.plainObjects?{__proto__:null}:{};for(var i="string"==typeof e?parseValues(e,r):e,a=r.plainObjects?{__proto__:null}:{},o=Object.keys(i),l=0;l<o.length;++l){var n=o[l],s=parseKeys(n,i[n],r,"string"==typeof e);a=utils.merge(a,s,r)}return!0===r.allowSparse?a:utils.compact(a)};
+
+},{"5":5}],4:[function(require,module,exports){
+"use strict";var getSideChannel=require(46),utils=require(5),formats=require(1),has=Object.prototype.hasOwnProperty,arrayPrefixGenerators={brackets:function brackets(e){return e+"[]"},comma:"comma",indices:function indices(e,r){return e+"["+r+"]"},repeat:function repeat(e){return e}},isArray=Array.isArray,push=Array.prototype.push,pushToArray=function(e,r){push.apply(e,isArray(r)?r:[r])},toISO=Date.prototype.toISOString,defaultFormat=formats.default,defaults={addQueryPrefix:!1,allowDots:!1,allowEmptyArrays:!1,arrayFormat:"indices",charset:"utf-8",charsetSentinel:!1,commaRoundTrip:!1,delimiter:"&",encode:!0,encodeDotInKeys:!1,encoder:utils.encode,encodeValuesOnly:!1,filter:void 0,format:defaultFormat,formatter:formats.formatters[defaultFormat],indices:!1,serializeDate:function serializeDate(e){return toISO.call(e)},skipNulls:!1,strictNullHandling:!1},isNonNullishPrimitive=function isNonNullishPrimitive(e){return"string"==typeof e||"number"==typeof e||"boolean"==typeof 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new TypeError("Encoder has to be a function.");var r=e.charset||defaults.charset;if(void 0!==e.charset&&"utf-8"!==e.charset&&"iso-8859-1"!==e.charset)throw new TypeError("The charset option must be either utf-8, iso-8859-1, or undefined");var t=formats.default;if(void 0!==e.format){if(!has.call(formats.formatters,e.format))throw new TypeError("Unknown format option provided.");t=e.format}var o,a=formats.formatters[t],n=defaults.filter;if(("function"==typeof e.filter||isArray(e.filter))&&(n=e.filter),o=e.arrayFormat in arrayPrefixGenerators?e.arrayFormat:"indices"in e?e.indices?"indices":"repeat":defaults.arrayFormat,"commaRoundTrip"in e&&"boolean"!=typeof e.commaRoundTrip)throw new TypeError("`commaRoundTrip` must be a boolean, or absent");var i=void 0===e.allowDots?!0===e.encodeDotInKeys||defaults.allowDots:!!e.allowDots;return{addQueryPrefix:"boolean"==typeof e.addQueryPrefix?e.addQueryPrefix:defaults.addQueryPrefix,allowDots:i,allowEmptyArrays:"boolean"==typeof e.allowEmptyArrays?!!e.allowEmptyArrays:defaults.allowEmptyArrays,arrayFormat:o,charset:r,charsetSentinel:"boolean"==typeof e.charsetSentinel?e.charsetSentinel:defaults.charsetSentinel,commaRoundTrip:!!e.commaRoundTrip,delimiter:void 0===e.delimiter?defaults.delimiter:e.delimiter,encode:"boolean"==typeof e.encode?e.encode:defaults.encode,encodeDotInKeys:"boolean"==typeof e.encodeDotInKeys?e.encodeDotInKeys:defaults.encodeDotInKeys,encoder:"function"==typeof e.encoder?e.encoder:defaults.encoder,encodeValuesOnly:"boolean"==typeof e.encodeValuesOnly?e.encodeValuesOnly:defaults.encodeValuesOnly,filter:n,format:t,formatter:a,serializeDate:"function"==typeof e.serializeDate?e.serializeDate:defaults.serializeDate,skipNulls:"boolean"==typeof e.skipNulls?e.skipNulls:defaults.skipNulls,sort:"function"==typeof e.sort?e.sort:null,strictNullHandling:"boolean"==typeof e.strictNullHandling?e.strictNullHandling:defaults.strictNullHandling}};module.exports=function(e,r){var t,o=e,a=normalizeStringifyOptions(r);"function"==typeof a.filter?o=(0,a.filter)("",o):isArray(a.filter)&&(t=a.filter);var n=[];if("object"!=typeof o||null===o)return"";var i=arrayPrefixGenerators[a.arrayFormat],l="comma"===i&&a.commaRoundTrip;t||(t=Object.keys(o)),a.sort&&t.sort(a.sort);for(var s=getSideChannel(),f=0;f<t.length;++f){var u=t[f],d=o[u];a.skipNulls&&null===d||pushToArray(n,stringify(d,u,i,l,a.allowEmptyArrays,a.strictNullHandling,a.skipNulls,a.encodeDotInKeys,a.encode?a.encoder:null,a.filter,a.sort,a.allowDots,a.serializeDate,a.format,a.formatter,a.encodeValuesOnly,a.charset,s))}var y=n.join(a.delimiter),c=!0===a.addQueryPrefix?"?":"";return a.charsetSentinel&&("iso-8859-1"===a.charset?c+="utf8=%26%2310003%3B&":c+="utf8=%E2%9C%93&"),y.length>0?c+y:""};
+
+},{"1":1,"46":46,"5":5}],5:[function(require,module,exports){
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+
+},{}],16:[function(require,module,exports){
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+
+},{}],17:[function(require,module,exports){
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+
+},{}],18:[function(require,module,exports){
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+
+},{}],19:[function(require,module,exports){
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+
+},{}],21:[function(require,module,exports){
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+
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+},{}],38:[function(require,module,exports){
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+},{}],34:[function(require,module,exports){
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+},{}],39:[function(require,module,exports){
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+
+},{}],27:[function(require,module,exports){
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+
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+},{"22":22}],33:[function(require,module,exports){
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+
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+
+},{}],36:[function(require,module,exports){
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+},{}],42:[function(require,module,exports){
+(function (global){(function (){
+var hasMap="function"==typeof Map&&Map.prototype,mapSizeDescriptor=Object.getOwnPropertyDescriptor&&hasMap?Object.getOwnPropertyDescriptor(Map.prototype,"size"):null,mapSize=hasMap&&mapSizeDescriptor&&"function"==typeof mapSizeDescriptor.get?mapSizeDescriptor.get:null,mapForEach=hasMap&&Map.prototype.forEach,hasSet="function"==typeof Set&&Set.prototype,setSizeDescriptor=Object.getOwnPropertyDescriptor&&hasSet?Object.getOwnPropertyDescriptor(Set.prototype,"size"):null,setSize=hasSet&&setSizeDescriptor&&"function"==typeof setSizeDescriptor.get?setSizeDescriptor.get:null,setForEach=hasSet&&Set.prototype.forEach,hasWeakMap="function"==typeof WeakMap&&WeakMap.prototype,weakMapHas=hasWeakMap?WeakMap.prototype.has:null,hasWeakSet="function"==typeof WeakSet&&WeakSet.prototype,weakSetHas=hasWeakSet?WeakSet.prototype.has:null,hasWeakRef="function"==typeof WeakRef&&WeakRef.prototype,weakRefDeref=hasWeakRef?WeakRef.prototype.deref:null,booleanValueOf=Boolean.prototype.valueOf,objectToString=Object.prototype.toString,functionToString=Function.prototype.toString,$match=String.prototype.match,$slice=String.prototype.slice,$replace=String.prototype.replace,$toUpperCase=String.prototype.toUpperCase,$toLowerCase=String.prototype.toLowerCase,$test=RegExp.prototype.test,$concat=Array.prototype.concat,$join=Array.prototype.join,$arrSlice=Array.prototype.slice,$floor=Math.floor,bigIntValueOf="function"==typeof BigInt?BigInt.prototype.valueOf:null,gOPS=Object.getOwnPropertySymbols,symToString="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?Symbol.prototype.toString:null,hasShammedSymbols="function"==typeof Symbol&&"object"==typeof Symbol.iterator,toStringTag="function"==typeof Symbol&&Symbol.toStringTag&&(Symbol.toStringTag,1)?Symbol.toStringTag:null,isEnumerable=Object.prototype.propertyIsEnumerable,gPO=("function"==typeof Reflect?Reflect.getPrototypeOf:Object.getPrototypeOf)||([].__proto__===Array.prototype?function(t){return t.__proto__}:null);function addNumericSeparator(t,e){if(t===1/0||t===-1/0||t!=t||t&&t>-1e3&&t<1e3||$test.call(/e/,e))return e;var r=/[0-9](?=(?:[0-9]{3})+(?![0-9]))/g;if("number"==typeof t){var n=t<0?-$floor(-t):$floor(t);if(n!==t){var o=String(n),i=$slice.call(e,o.length+1);return $replace.call(o,r,"$&_")+"."+$replace.call($replace.call(i,/([0-9]{3})/g,"$&_"),/_$/,"")}}return $replace.call(e,r,"$&_")}var utilInspect=require(6),inspectCustom=utilInspect.custom,inspectSymbol=isSymbol(inspectCustom)?inspectCustom:null,quotes={__proto__:null,double:'"',single:"'"},quoteREs={__proto__:null,double:/(["\\])/g,single:/(['\\])/g};function wrapQuotes(t,e,r){var n=r.quoteStyle||e,o=quotes[n];return o+t+o}function quote(t){return $replace.call(String(t),/"/g,""")}function canTrustToString(t){return!toStringTag||!("object"==typeof t&&(toStringTag in t||void 0!==t[toStringTag]))}function isArray(t){return"[object Array]"===toStr(t)&&canTrustToString(t)}function isDate(t){return"[object Date]"===toStr(t)&&canTrustToString(t)}function isRegExp(t){return"[object RegExp]"===toStr(t)&&canTrustToString(t)}function isError(t){return"[object Error]"===toStr(t)&&canTrustToString(t)}function isString(t){return"[object String]"===toStr(t)&&canTrustToString(t)}function isNumber(t){return"[object Number]"===toStr(t)&&canTrustToString(t)}function isBoolean(t){return"[object Boolean]"===toStr(t)&&canTrustToString(t)}function isSymbol(t){if(hasShammedSymbols)return t&&"object"==typeof t&&t instanceof Symbol;if("symbol"==typeof t)return!0;if(!t||"object"!=typeof t||!symToString)return!1;try{return symToString.call(t),!0}catch(t){}return!1}function isBigInt(t){if(!t||"object"!=typeof t||!bigIntValueOf)return!1;try{return bigIntValueOf.call(t),!0}catch(t){}return!1}module.exports=function inspect_(t,e,r,n){var o=e||{};if(has(o,"quoteStyle")&&!has(quotes,o.quoteStyle))throw new TypeError('option "quoteStyle" must be "single" or "double"');if(has(o,"maxStringLength")&&("number"==typeof o.maxStringLength?o.maxStringLength<0&&o.maxStringLength!==1/0:null!==o.maxStringLength))throw new TypeError('option "maxStringLength", if provided, must be a positive integer, Infinity, or `null`');var i=!has(o,"customInspect")||o.customInspect;if("boolean"!=typeof i&&"symbol"!==i)throw new TypeError("option \"customInspect\", if provided, must be `true`, `false`, or `'symbol'`");if(has(o,"indent")&&null!==o.indent&&"\t"!==o.indent&&!(parseInt(o.indent,10)===o.indent&&o.indent>0))throw new TypeError('option "indent" must be "\\t", an integer > 0, or `null`');if(has(o,"numericSeparator")&&"boolean"!=typeof o.numericSeparator)throw new TypeError('option "numericSeparator", if provided, must be `true` or `false`');var a=o.numericSeparator;if(void 0===t)return"undefined";if(null===t)return"null";if("boolean"==typeof t)return t?"true":"false";if("string"==typeof t)return inspectString(t,o);if("number"==typeof t){if(0===t)return 1/0/t>0?"0":"-0";var c=String(t);return a?addNumericSeparator(t,c):c}if("bigint"==typeof t){var l=String(t)+"n";return a?addNumericSeparator(t,l):l}var u=void 0===o.depth?5:o.depth;if(void 0===r&&(r=0),r>=u&&u>0&&"object"==typeof t)return isArray(t)?"[Array]":"[Object]";var p=getIndent(o,r);if(void 0===n)n=[];else if(indexOf(n,t)>=0)return"[Circular]";function inspect(t,e,i){if(e&&(n=$arrSlice.call(n)).push(e),i){var a={depth:o.depth};return has(o,"quoteStyle")&&(a.quoteStyle=o.quoteStyle),inspect_(t,a,r+1,n)}return inspect_(t,o,r+1,n)}if("function"==typeof t&&!isRegExp(t)){var s=nameOf(t),f=arrObjKeys(t,inspect);return"[Function"+(s?": "+s:" (anonymous)")+"]"+(f.length>0?" { "+$join.call(f,", ")+" }":"")}if(isSymbol(t)){var y=hasShammedSymbols?$replace.call(String(t),/^(Symbol$.*$)_[^)]*$/,"$1"):symToString.call(t);return"object"!=typeof t||hasShammedSymbols?y:markBoxed(y)}if(isElement(t)){for(var S="<"+$toLowerCase.call(String(t.nodeName)),g=t.attributes||[],m=0;m<g.length;m++)S+=" "+g[m].name+"="+wrapQuotes(quote(g[m].value),"double",o);return S+=">",t.childNodes&&t.childNodes.length&&(S+="..."),S+"</"+$toLowerCase.call(String(t.nodeName))+">"}if(isArray(t)){if(0===t.length)return"[]";var b=arrObjKeys(t,inspect);return p&&!singleLineValues(b)?"["+indentedJoin(b,p)+"]":"[ "+$join.call(b,", ")+" ]"}if(isError(t)){var h=arrObjKeys(t,inspect);return"cause"in Error.prototype||!("cause"in t)||isEnumerable.call(t,"cause")?0===h.length?"["+String(t)+"]":"{ ["+String(t)+"] "+$join.call(h,", ")+" }":"{ ["+String(t)+"] "+$join.call($concat.call("[cause]: "+inspect(t.cause),h),", ")+" }"}if("object"==typeof t&&i){if(inspectSymbol&&"function"==typeof t[inspectSymbol]&&utilInspect)return utilInspect(t,{depth:u-r});if("symbol"!==i&&"function"==typeof t.inspect)return t.inspect()}if(isMap(t)){var d=[];return mapForEach&&mapForEach.call(t,function(e,r){d.push(inspect(r,t,!0)+" => "+inspect(e,t))}),collectionOf("Map",mapSize.call(t),d,p)}if(isSet(t)){var O=[];return setForEach&&setForEach.call(t,function(e){O.push(inspect(e,t))}),collectionOf("Set",setSize.call(t),O,p)}if(isWeakMap(t))return weakCollectionOf("WeakMap");if(isWeakSet(t))return weakCollectionOf("WeakSet");if(isWeakRef(t))return weakCollectionOf("WeakRef");if(isNumber(t))return markBoxed(inspect(Number(t)));if(isBigInt(t))return markBoxed(inspect(bigIntValueOf.call(t)));if(isBoolean(t))return markBoxed(booleanValueOf.call(t));if(isString(t))return markBoxed(inspect(String(t)));if("undefined"!=typeof window&&t===window)return"{ [object Window] }";if("undefined"!=typeof globalThis&&t===globalThis||"undefined"!=typeof global&&t===global)return"{ [object globalThis] }";if(!isDate(t)&&!isRegExp(t)){var j=arrObjKeys(t,inspect),w=gPO?gPO(t)===Object.prototype:t instanceof Object||t.constructor===Object,$=t instanceof Object?"":"null prototype",v=!w&&toStringTag&&Object(t)===t&&toStringTag in t?$slice.call(toStr(t),8,-1):$?"Object":"",k=(w||"function"!=typeof t.constructor?"":t.constructor.name?t.constructor.name+" ":"")+(v||$?"["+$join.call($concat.call([],v||[],$||[]),": ")+"] ":"");return 0===j.length?k+"{}":p?k+"{"+indentedJoin(j,p)+"}":k+"{ "+$join.call(j,", ")+" }"}return String(t)};var hasOwn=Object.prototype.hasOwnProperty||function(t){return t in this};function has(t,e){return hasOwn.call(t,e)}function toStr(t){return objectToString.call(t)}function nameOf(t){if(t.name)return t.name;var e=$match.call(functionToString.call(t),/^function\s*([\w$]+)/);return e?e[1]:null}function indexOf(t,e){if(t.indexOf)return t.indexOf(e);for(var r=0,n=t.length;r<n;r++)if(t[r]===e)return r;return-1}function isMap(t){if(!mapSize||!t||"object"!=typeof t)return!1;try{mapSize.call(t);try{setSize.call(t)}catch(t){return!0}return t instanceof Map}catch(t){}return!1}function isWeakMap(t){if(!weakMapHas||!t||"object"!=typeof t)return!1;try{weakMapHas.call(t,weakMapHas);try{weakSetHas.call(t,weakSetHas)}catch(t){return!0}return t instanceof WeakMap}catch(t){}return!1}function isWeakRef(t){if(!weakRefDeref||!t||"object"!=typeof t)return!1;try{return weakRefDeref.call(t),!0}catch(t){}return!1}function isSet(t){if(!setSize||!t||"object"!=typeof t)return!1;try{setSize.call(t);try{mapSize.call(t)}catch(t){return!0}return t instanceof Set}catch(t){}return!1}function isWeakSet(t){if(!weakSetHas||!t||"object"!=typeof t)return!1;try{weakSetHas.call(t,weakSetHas);try{weakMapHas.call(t,weakMapHas)}catch(t){return!0}return t instanceof WeakSet}catch(t){}return!1}function isElement(t){return!(!t||"object"!=typeof t)&&("undefined"!=typeof HTMLElement&&t instanceof HTMLElement||"string"==typeof t.nodeName&&"function"==typeof t.getAttribute)}function inspectString(t,e){if(t.length>e.maxStringLength){var r=t.length-e.maxStringLength,n="... "+r+" more character"+(r>1?"s":"");return inspectString($slice.call(t,0,e.maxStringLength),e)+n}var o=quoteREs[e.quoteStyle||"single"];return o.lastIndex=0,wrapQuotes($replace.call($replace.call(t,o,"\\$1"),/[\x00-\x1f]/g,lowbyte),"single",e)}function lowbyte(t){var e=t.charCodeAt(0),r={8:"b",9:"t",10:"n",12:"f",13:"r"}[e];return r?"\\"+r:"\\x"+(e<16?"0":"")+$toUpperCase.call(e.toString(16))}function markBoxed(t){return"Object("+t+")"}function weakCollectionOf(t){return t+" { ? }"}function collectionOf(t,e,r,n){return t+" ("+e+") {"+(n?indentedJoin(r,n):$join.call(r,", "))+"}"}function singleLineValues(t){for(var e=0;e<t.length;e++)if(indexOf(t[e],"\n")>=0)return!1;return!0}function getIndent(t,e){var r;if("\t"===t.indent)r="\t";else{if(!("number"==typeof t.indent&&t.indent>0))return null;r=$join.call(Array(t.indent+1)," ")}return{base:r,prev:$join.call(Array(e+1),r)}}function indentedJoin(t,e){if(0===t.length)return"";var r="\n"+e.prev+e.base;return r+$join.call(t,","+r)+"\n"+e.prev}function arrObjKeys(t,e){var r=isArray(t),n=[];if(r){n.length=t.length;for(var o=0;o<t.length;o++)n[o]=has(t,o)?e(t[o],t):""}var i,a="function"==typeof gOPS?gOPS(t):[];if(hasShammedSymbols){i={};for(var c=0;c<a.length;c++)i["$"+a[c]]=a[c]}for(var l in t)has(t,l)&&(r&&String(Number(l))===l&&l<t.length||hasShammedSymbols&&i["$"+l]instanceof Symbol||($test.call(/[^\w$]/,l)?n.push(e(l,t)+": "+e(t[l],t)):n.push(l+": "+e(t[l],t))));if("function"==typeof gOPS)for(var u=0;u<a.length;u++)isEnumerable.call(t,a[u])&&n.push("["+e(a[u])+"]: "+e(t[a[u]],t));return n}
+
+}).call(this)}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
+},{"6":6}],43:[function(require,module,exports){
+"use strict";var inspect=require(42),$TypeError=require(20),listGetNode=function(e,t,n){for(var i,r=e;null!=(i=r.next);r=i)if(i.key===t)return r.next=i.next,n||(i.next=e.next,e.next=i),i},listGet=function(e,t){if(e){var n=listGetNode(e,t);return n&&n.value}},listSet=function(e,t,n){var i=listGetNode(e,t);i?i.value=n:e.next={key:t,next:e.next,value:n}},listHas=function(e,t){return!!e&&!!listGetNode(e,t)},listDelete=function(e,t){if(e)return listGetNode(e,t,!0)};module.exports=function getSideChannelList(){var e,t={assert:function(e){if(!t.has(e))throw new $TypeError("Side channel does not contain "+inspect(e))},delete:function(t){var n=e&&e.next,i=listDelete(e,t);return i&&n&&n===i&&(e=void 0),!!i},get:function(t){return listGet(e,t)},has:function(t){return listHas(e,t)},set:function(t,n){e||(e={next:void 0}),listSet(e,t,n)}};return t};
+
+},{"20":20,"42":42}],44:[function(require,module,exports){
+"use strict";var GetIntrinsic=require(25),callBound=require(12),inspect=require(42),$TypeError=require(20),$Map=GetIntrinsic("%Map%",!0),$mapGet=callBound("Map.prototype.get",!0),$mapSet=callBound("Map.prototype.set",!0),$mapHas=callBound("Map.prototype.has",!0),$mapDelete=callBound("Map.prototype.delete",!0),$mapSize=callBound("Map.prototype.size",!0);module.exports=!!$Map&&function getSideChannelMap(){var e,t={assert:function(e){if(!t.has(e))throw new $TypeError("Side channel does not contain "+inspect(e))},delete:function(t){if(e){var n=$mapDelete(e,t);return 0===$mapSize(e)&&(e=void 0),n}return!1},get:function(t){if(e)return $mapGet(e,t)},has:function(t){return!!e&&$mapHas(e,t)},set:function(t,n){e||(e=new $Map),$mapSet(e,t,n)}};return t};
+
+},{"12":12,"20":20,"25":25,"42":42}],45:[function(require,module,exports){
+"use strict";var GetIntrinsic=require(25),callBound=require(12),inspect=require(42),getSideChannelMap=require(44),$TypeError=require(20),$WeakMap=GetIntrinsic("%WeakMap%",!0),$weakMapGet=callBound("WeakMap.prototype.get",!0),$weakMapSet=callBound("WeakMap.prototype.set",!0),$weakMapHas=callBound("WeakMap.prototype.has",!0),$weakMapDelete=callBound("WeakMap.prototype.delete",!0);module.exports=$WeakMap?function getSideChannelWeakMap(){var e,t,a={assert:function(e){if(!a.has(e))throw new $TypeError("Side channel does not contain "+inspect(e))},delete:function(a){if($WeakMap&&a&&("object"==typeof a||"function"==typeof a)){if(e)return $weakMapDelete(e,a)}else if(getSideChannelMap&&t)return t.delete(a);return!1},get:function(a){return $WeakMap&&a&&("object"==typeof a||"function"==typeof a)&&e?$weakMapGet(e,a):t&&t.get(a)},has:function(a){return $WeakMap&&a&&("object"==typeof a||"function"==typeof a)&&e?$weakMapHas(e,a):!!t&&t.has(a)},set:function(a,n){$WeakMap&&a&&("object"==typeof a||"function"==typeof a)?(e||(e=new $WeakMap),$weakMapSet(e,a,n)):getSideChannelMap&&(t||(t=getSideChannelMap()),t.set(a,n))}};return a}:getSideChannelMap;
+
+},{"12":12,"20":20,"25":25,"42":42,"44":44}]},{},[2])(2)
+});
diff --git a/server/node_modules/qs/eslint.config.mjs b/server/node_modules/qs/eslint.config.mjs
new file mode 100644
index 0000000..bdde6e9
--- /dev/null
+++ b/server/node_modules/qs/eslint.config.mjs
@@ -0,0 +1,56 @@
+import ljharbConfig from '@ljharb/eslint-config/flat';
+
+export default [
+    {
+        ignores: ['dist/'],
+    },
+
+    ...ljharbConfig,
+
+    {
+        rules: {
+            complexity: 'off',
+            'consistent-return': 'warn',
+            'func-name-matching': 'off',
+            'id-length': [
+                'error',
+                {
+                    max: 25,
+                    min: 1,
+                    properties: 'never',
+                },
+            ],
+            indent: ['error', 4],
+            'max-lines': 'off',
+            'max-lines-per-function': [
+                'error',
+                { max: 150 },
+            ],
+            'max-params': ['error', 18],
+            'max-statements': ['error', 100],
+            'multiline-comment-style': 'off',
+            'no-continue': 'warn',
+            'no-magic-numbers': 'off',
+            'no-restricted-syntax': [
+                'error',
+                'BreakStatement',
+                'DebuggerStatement',
+                'ForInStatement',
+                'LabeledStatement',
+                'WithStatement',
+            ],
+        },
+    },
+
+    {
+        files: ['test/**'],
+        rules: {
+            'function-paren-newline': 'off',
+            'max-lines-per-function': 'off',
+            'max-statements': 'off',
+            'no-buffer-constructor': 'off',
+            'no-extend-native': 'off',
+            'no-throw-literal': 'off',
+        },
+    },
+];
diff --git a/server/node_modules/qs/lib/formats.js b/server/node_modules/qs/lib/formats.js
new file mode 100644
index 0000000..f36cf20
--- /dev/null
+++ b/server/node_modules/qs/lib/formats.js
@@ -0,0 +1,23 @@
+'use strict';
+
+var replace = String.prototype.replace;
+var percentTwenties = /%20/g;
+
+var Format = {
+    RFC1738: 'RFC1738',
+    RFC3986: 'RFC3986'
+};
+
+module.exports = {
+    'default': Format.RFC3986,
+    formatters: {
+        RFC1738: function (value) {
+            return replace.call(value, percentTwenties, '+');
+        },
+        RFC3986: function (value) {
+            return String(value);
+        }
+    },
+    RFC1738: Format.RFC1738,
+    RFC3986: Format.RFC3986
+};
diff --git a/server/node_modules/qs/lib/index.js b/server/node_modules/qs/lib/index.js
new file mode 100644
index 0000000..0d6a97d
--- /dev/null
+++ b/server/node_modules/qs/lib/index.js
@@ -0,0 +1,11 @@
+'use strict';
+
+var stringify = require('./stringify');
+var parse = require('./parse');
+var formats = require('./formats');
+
+module.exports = {
+    formats: formats,
+    parse: parse,
+    stringify: stringify
+};
diff --git a/server/node_modules/qs/lib/parse.js b/server/node_modules/qs/lib/parse.js
new file mode 100644
index 0000000..621c41e
--- /dev/null
+++ b/server/node_modules/qs/lib/parse.js
@@ -0,0 +1,360 @@
+'use strict';
+
+var utils = require('./utils');
+
+var has = Object.prototype.hasOwnProperty;
+var isArray = Array.isArray;
+
+var defaults = {
+    allowDots: false,
+    allowEmptyArrays: false,
+    allowPrototypes: false,
+    allowSparse: false,
+    arrayLimit: 20,
+    charset: 'utf-8',
+    charsetSentinel: false,
+    comma: false,
+    decodeDotInKeys: false,
+    decoder: utils.decode,
+    delimiter: '&',
+    depth: 5,
+    duplicates: 'combine',
+    ignoreQueryPrefix: false,
+    interpretNumericEntities: false,
+    parameterLimit: 1000,
+    parseArrays: true,
+    plainObjects: false,
+    strictDepth: false,
+    strictNullHandling: false,
+    throwOnLimitExceeded: false
+};
+
+var interpretNumericEntities = function (str) {
+    return str.replace(/&#(\d+);/g, function ($0, numberStr) {
+        return String.fromCharCode(parseInt(numberStr, 10));
+    });
+};
+
+var parseArrayValue = function (val, options, currentArrayLength) {
+    if (val && typeof val === 'string' && options.comma && val.indexOf(',') > -1) {
+        return val.split(',');
+    }
+
+    if (options.throwOnLimitExceeded && currentArrayLength >= options.arrayLimit) {
+        throw new RangeError('Array limit exceeded. Only ' + options.arrayLimit + ' element' + (options.arrayLimit === 1 ? '' : 's') + ' allowed in an array.');
+    }
+
+    return val;
+};
+
+// This is what browsers will submit when the ✓ character occurs in an
+// application/x-www-form-urlencoded body and the encoding of the page containing
+// the form is iso-8859-1, or when the submitted form has an accept-charset
+// attribute of iso-8859-1. Presumably also with other charsets that do not contain
+// the ✓ character, such as us-ascii.
+var isoSentinel = 'utf8=%26%2310003%3B'; // encodeURIComponent('✓')
+
+// These are the percent-encoded utf-8 octets representing a checkmark, indicating that the request actually is utf-8 encoded.
+var charsetSentinel = 'utf8=%E2%9C%93'; // encodeURIComponent('✓')
+
+var parseValues = function parseQueryStringValues(str, options) {
+    var obj = { __proto__: null };
+
+    var cleanStr = options.ignoreQueryPrefix ? str.replace(/^\?/, '') : str;
+    cleanStr = cleanStr.replace(/%5B/gi, '[').replace(/%5D/gi, ']');
+
+    var limit = options.parameterLimit === Infinity ? undefined : options.parameterLimit;
+    var parts = cleanStr.split(
+        options.delimiter,
+        options.throwOnLimitExceeded ? limit + 1 : limit
+    );
+
+    if (options.throwOnLimitExceeded && parts.length > limit) {
+        throw new RangeError('Parameter limit exceeded. Only ' + limit + ' parameter' + (limit === 1 ? '' : 's') + ' allowed.');
+    }
+
+    var skipIndex = -1; // Keep track of where the utf8 sentinel was found
+    var i;
+
+    var charset = options.charset;
+    if (options.charsetSentinel) {
+        for (i = 0; i < parts.length; ++i) {
+            if (parts[i].indexOf('utf8=') === 0) {
+                if (parts[i] === charsetSentinel) {
+                    charset = 'utf-8';
+                } else if (parts[i] === isoSentinel) {
+                    charset = 'iso-8859-1';
+                }
+                skipIndex = i;
+                i = parts.length; // The eslint settings do not allow break;
+            }
+        }
+    }
+
+    for (i = 0; i < parts.length; ++i) {
+        if (i === skipIndex) {
+            continue;
+        }
+        var part = parts[i];
+
+        var bracketEqualsPos = part.indexOf(']=');
+        var pos = bracketEqualsPos === -1 ? part.indexOf('=') : bracketEqualsPos + 1;
+
+        var key;
+        var val;
+        if (pos === -1) {
+            key = options.decoder(part, defaults.decoder, charset, 'key');
+            val = options.strictNullHandling ? null : '';
+        } else {
+            key = options.decoder(part.slice(0, pos), defaults.decoder, charset, 'key');
+
+            if (key !== null) {
+                val = utils.maybeMap(
+                    parseArrayValue(
+                        part.slice(pos + 1),
+                        options,
+                        isArray(obj[key]) ? obj[key].length : 0
+                    ),
+                    function (encodedVal) {
+                        return options.decoder(encodedVal, defaults.decoder, charset, 'value');
+                    }
+                );
+            }
+        }
+
+        if (val && options.interpretNumericEntities && charset === 'iso-8859-1') {
+            val = interpretNumericEntities(String(val));
+        }
+
+        if (part.indexOf('[]=') > -1) {
+            val = isArray(val) ? [val] : val;
+        }
+
+        if (key !== null) {
+            var existing = has.call(obj, key);
+            if (existing && options.duplicates === 'combine') {
+                obj[key] = utils.combine(
+                    obj[key],
+                    val,
+                    options.arrayLimit,
+                    options.plainObjects
+                );
+            } else if (!existing || options.duplicates === 'last') {
+                obj[key] = val;
+            }
+        }
+    }
+
+    return obj;
+};
+
+var parseObject = function (chain, val, options, valuesParsed) {
+    var currentArrayLength = 0;
+    if (chain.length > 0 && chain[chain.length - 1] === '[]') {
+        var parentKey = chain.slice(0, -1).join('');
+        currentArrayLength = Array.isArray(val) && val[parentKey] ? val[parentKey].length : 0;
+    }
+
+    var leaf = valuesParsed ? val : parseArrayValue(val, options, currentArrayLength);
+
+    for (var i = chain.length - 1; i >= 0; --i) {
+        var obj;
+        var root = chain[i];
+
+        if (root === '[]' && options.parseArrays) {
+            if (utils.isOverflow(leaf)) {
+                // leaf is already an overflow object, preserve it
+                obj = leaf;
+            } else {
+                obj = options.allowEmptyArrays && (leaf === '' || (options.strictNullHandling && leaf === null))
+                    ? []
+                    : utils.combine(
+                        [],
+                        leaf,
+                        options.arrayLimit,
+                        options.plainObjects
+                    );
+            }
+        } else {
+            obj = options.plainObjects ? { __proto__: null } : {};
+            var cleanRoot = root.charAt(0) === '[' && root.charAt(root.length - 1) === ']' ? root.slice(1, -1) : root;
+            var decodedRoot = options.decodeDotInKeys ? cleanRoot.replace(/%2E/g, '.') : cleanRoot;
+            var index = parseInt(decodedRoot, 10);
+            if (!options.parseArrays && decodedRoot === '') {
+                obj = { 0: leaf };
+            } else if (
+                !isNaN(index)
+                && root !== decodedRoot
+                && String(index) === decodedRoot
+                && index >= 0
+                && (options.parseArrays && index <= options.arrayLimit)
+            ) {
+                obj = [];
+                obj[index] = leaf;
+            } else if (decodedRoot !== '__proto__') {
+                obj[decodedRoot] = leaf;
+            }
+        }
+
+        leaf = obj;
+    }
+
+    return leaf;
+};
+
+var splitKeyIntoSegments = function splitKeyIntoSegments(givenKey, options) {
+    var key = options.allowDots ? givenKey.replace(/\.([^.[]+)/g, '[$1]') : givenKey;
+
+    if (options.depth <= 0) {
+        if (!options.plainObjects && has.call(Object.prototype, key)) {
+            if (!options.allowPrototypes) {
+                return;
+            }
+        }
+
+        return [key];
+    }
+
+    var brackets = /(\[[^[\]]*])/;
+    var child = /(\[[^[\]]*])/g;
+
+    var segment = brackets.exec(key);
+    var parent = segment ? key.slice(0, segment.index) : key;
+
+    var keys = [];
+
+    if (parent) {
+        if (!options.plainObjects && has.call(Object.prototype, parent)) {
+            if (!options.allowPrototypes) {
+                return;
+            }
+        }
+
+        keys.push(parent);
+    }
+
+    var i = 0;
+    while ((segment = child.exec(key)) !== null && i < options.depth) {
+        i += 1;
+
+        var segmentContent = segment[1].slice(1, -1);
+        if (!options.plainObjects && has.call(Object.prototype, segmentContent)) {
+            if (!options.allowPrototypes) {
+                return;
+            }
+        }
+
+        keys.push(segment[1]);
+    }
+
+    if (segment) {
+        if (options.strictDepth === true) {
+            throw new RangeError('Input depth exceeded depth option of ' + options.depth + ' and strictDepth is true');
+        }
+
+        keys.push('[' + key.slice(segment.index) + ']');
+    }
+
+    return keys;
+};
+
+var parseKeys = function parseQueryStringKeys(givenKey, val, options, valuesParsed) {
+    if (!givenKey) {
+        return;
+    }
+
+    var keys = splitKeyIntoSegments(givenKey, options);
+
+    if (!keys) {
+        return;
+    }
+
+    return parseObject(keys, val, options, valuesParsed);
+};
+
+var normalizeParseOptions = function normalizeParseOptions(opts) {
+    if (!opts) {
+        return defaults;
+    }
+
+    if (typeof opts.allowEmptyArrays !== 'undefined' && typeof opts.allowEmptyArrays !== 'boolean') {
+        throw new TypeError('`allowEmptyArrays` option can only be `true` or `false`, when provided');
+    }
+
+    if (typeof opts.decodeDotInKeys !== 'undefined' && typeof opts.decodeDotInKeys !== 'boolean') {
+        throw new TypeError('`decodeDotInKeys` option can only be `true` or `false`, when provided');
+    }
+
+    if (opts.decoder !== null && typeof opts.decoder !== 'undefined' && typeof opts.decoder !== 'function') {
+        throw new TypeError('Decoder has to be a function.');
+    }
+
+    if (typeof opts.charset !== 'undefined' && opts.charset !== 'utf-8' && opts.charset !== 'iso-8859-1') {
+        throw new TypeError('The charset option must be either utf-8, iso-8859-1, or undefined');
+    }
+
+    if (typeof opts.throwOnLimitExceeded !== 'undefined' && typeof opts.throwOnLimitExceeded !== 'boolean') {
+        throw new TypeError('`throwOnLimitExceeded` option must be a boolean');
+    }
+
+    var charset = typeof opts.charset === 'undefined' ? defaults.charset : opts.charset;
+
+    var duplicates = typeof opts.duplicates === 'undefined' ? defaults.duplicates : opts.duplicates;
+
+    if (duplicates !== 'combine' && duplicates !== 'first' && duplicates !== 'last') {
+        throw new TypeError('The duplicates option must be either combine, first, or last');
+    }
+
+    var allowDots = typeof opts.allowDots === 'undefined' ? opts.decodeDotInKeys === true ? true : defaults.allowDots : !!opts.allowDots;
+
+    return {
+        allowDots: allowDots,
+        allowEmptyArrays: typeof opts.allowEmptyArrays === 'boolean' ? !!opts.allowEmptyArrays : defaults.allowEmptyArrays,
+        allowPrototypes: typeof opts.allowPrototypes === 'boolean' ? opts.allowPrototypes : defaults.allowPrototypes,
+        allowSparse: typeof opts.allowSparse === 'boolean' ? opts.allowSparse : defaults.allowSparse,
+        arrayLimit: typeof opts.arrayLimit === 'number' ? opts.arrayLimit : defaults.arrayLimit,
+        charset: charset,
+        charsetSentinel: typeof opts.charsetSentinel === 'boolean' ? opts.charsetSentinel : defaults.charsetSentinel,
+        comma: typeof opts.comma === 'boolean' ? opts.comma : defaults.comma,
+        decodeDotInKeys: typeof opts.decodeDotInKeys === 'boolean' ? opts.decodeDotInKeys : defaults.decodeDotInKeys,
+        decoder: typeof opts.decoder === 'function' ? opts.decoder : defaults.decoder,
+        delimiter: typeof opts.delimiter === 'string' || utils.isRegExp(opts.delimiter) ? opts.delimiter : defaults.delimiter,
+        // eslint-disable-next-line no-implicit-coercion, no-extra-parens
+        depth: (typeof opts.depth === 'number' || opts.depth === false) ? +opts.depth : defaults.depth,
+        duplicates: duplicates,
+        ignoreQueryPrefix: opts.ignoreQueryPrefix === true,
+        interpretNumericEntities: typeof opts.interpretNumericEntities === 'boolean' ? opts.interpretNumericEntities : defaults.interpretNumericEntities,
+        parameterLimit: typeof opts.parameterLimit === 'number' ? opts.parameterLimit : defaults.parameterLimit,
+        parseArrays: opts.parseArrays !== false,
+        plainObjects: typeof opts.plainObjects === 'boolean' ? opts.plainObjects : defaults.plainObjects,
+        strictDepth: typeof opts.strictDepth === 'boolean' ? !!opts.strictDepth : defaults.strictDepth,
+        strictNullHandling: typeof opts.strictNullHandling === 'boolean' ? opts.strictNullHandling : defaults.strictNullHandling,
+        throwOnLimitExceeded: typeof opts.throwOnLimitExceeded === 'boolean' ? opts.throwOnLimitExceeded : false
+    };
+};
+
+module.exports = function (str, opts) {
+    var options = normalizeParseOptions(opts);
+
+    if (str === '' || str === null || typeof str === 'undefined') {
+        return options.plainObjects ? { __proto__: null } : {};
+    }
+
+    var tempObj = typeof str === 'string' ? parseValues(str, options) : str;
+    var obj = options.plainObjects ? { __proto__: null } : {};
+
+    // Iterate over the keys and setup the new object
+
+    var keys = Object.keys(tempObj);
+    for (var i = 0; i < keys.length; ++i) {
+        var key = keys[i];
+        var newObj = parseKeys(key, tempObj[key], options, typeof str === 'string');
+        obj = utils.merge(obj, newObj, options);
+    }
+
+    if (options.allowSparse === true) {
+        return obj;
+    }
+
+    return utils.compact(obj);
+};
diff --git a/server/node_modules/qs/lib/stringify.js b/server/node_modules/qs/lib/stringify.js
new file mode 100644
index 0000000..2666eaf
--- /dev/null
+++ b/server/node_modules/qs/lib/stringify.js
@@ -0,0 +1,356 @@
+'use strict';
+
+var getSideChannel = require('side-channel');
+var utils = require('./utils');
+var formats = require('./formats');
+var has = Object.prototype.hasOwnProperty;
+
+var arrayPrefixGenerators = {
+    brackets: function brackets(prefix) {
+        return prefix + '[]';
+    },
+    comma: 'comma',
+    indices: function indices(prefix, key) {
+        return prefix + '[' + key + ']';
+    },
+    repeat: function repeat(prefix) {
+        return prefix;
+    }
+};
+
+var isArray = Array.isArray;
+var push = Array.prototype.push;
+var pushToArray = function (arr, valueOrArray) {
+    push.apply(arr, isArray(valueOrArray) ? valueOrArray : [valueOrArray]);
+};
+
+var toISO = Date.prototype.toISOString;
+
+var defaultFormat = formats['default'];
+var defaults = {
+    addQueryPrefix: false,
+    allowDots: false,
+    allowEmptyArrays: false,
+    arrayFormat: 'indices',
+    charset: 'utf-8',
+    charsetSentinel: false,
+    commaRoundTrip: false,
+    delimiter: '&',
+    encode: true,
+    encodeDotInKeys: false,
+    encoder: utils.encode,
+    encodeValuesOnly: false,
+    filter: void undefined,
+    format: defaultFormat,
+    formatter: formats.formatters[defaultFormat],
+    // deprecated
+    indices: false,
+    serializeDate: function serializeDate(date) {
+        return toISO.call(date);
+    },
+    skipNulls: false,
+    strictNullHandling: false
+};
+
+var isNonNullishPrimitive = function isNonNullishPrimitive(v) {
+    return typeof v === 'string'
+        || typeof v === 'number'
+        || typeof v === 'boolean'
+        || typeof v === 'symbol'
+        || typeof v === 'bigint';
+};
+
+var sentinel = {};
+
+var stringify = function stringify(
+    object,
+    prefix,
+    generateArrayPrefix,
+    commaRoundTrip,
+    allowEmptyArrays,
+    strictNullHandling,
+    skipNulls,
+    encodeDotInKeys,
+    encoder,
+    filter,
+    sort,
+    allowDots,
+    serializeDate,
+    format,
+    formatter,
+    encodeValuesOnly,
+    charset,
+    sideChannel
+) {
+    var obj = object;
+
+    var tmpSc = sideChannel;
+    var step = 0;
+    var findFlag = false;
+    while ((tmpSc = tmpSc.get(sentinel)) !== void undefined && !findFlag) {
+        // Where object last appeared in the ref tree
+        var pos = tmpSc.get(object);
+        step += 1;
+        if (typeof pos !== 'undefined') {
+            if (pos === step) {
+                throw new RangeError('Cyclic object value');
+            } else {
+                findFlag = true; // Break while
+            }
+        }
+        if (typeof tmpSc.get(sentinel) === 'undefined') {
+            step = 0;
+        }
+    }
+
+    if (typeof filter === 'function') {
+        obj = filter(prefix, obj);
+    } else if (obj instanceof Date) {
+        obj = serializeDate(obj);
+    } else if (generateArrayPrefix === 'comma' && isArray(obj)) {
+        obj = utils.maybeMap(obj, function (value) {
+            if (value instanceof Date) {
+                return serializeDate(value);
+            }
+            return value;
+        });
+    }
+
+    if (obj === null) {
+        if (strictNullHandling) {
+            return encoder && !encodeValuesOnly ? encoder(prefix, defaults.encoder, charset, 'key', format) : prefix;
+        }
+
+        obj = '';
+    }
+
+    if (isNonNullishPrimitive(obj) || utils.isBuffer(obj)) {
+        if (encoder) {
+            var keyValue = encodeValuesOnly ? prefix : encoder(prefix, defaults.encoder, charset, 'key', format);
+            return [formatter(keyValue) + '=' + formatter(encoder(obj, defaults.encoder, charset, 'value', format))];
+        }
+        return [formatter(prefix) + '=' + formatter(String(obj))];
+    }
+
+    var values = [];
+
+    if (typeof obj === 'undefined') {
+        return values;
+    }
+
+    var objKeys;
+    if (generateArrayPrefix === 'comma' && isArray(obj)) {
+        // we need to join elements in
+        if (encodeValuesOnly && encoder) {
+            obj = utils.maybeMap(obj, encoder);
+        }
+        objKeys = [{ value: obj.length > 0 ? obj.join(',') || null : void undefined }];
+    } else if (isArray(filter)) {
+        objKeys = filter;
+    } else {
+        var keys = Object.keys(obj);
+        objKeys = sort ? keys.sort(sort) : keys;
+    }
+
+    var encodedPrefix = encodeDotInKeys ? String(prefix).replace(/\./g, '%2E') : String(prefix);
+
+    var adjustedPrefix = commaRoundTrip && isArray(obj) && obj.length === 1 ? encodedPrefix + '[]' : encodedPrefix;
+
+    if (allowEmptyArrays && isArray(obj) && obj.length === 0) {
+        return adjustedPrefix + '[]';
+    }
+
+    for (var j = 0; j < objKeys.length; ++j) {
+        var key = objKeys[j];
+        var value = typeof key === 'object' && key && typeof key.value !== 'undefined'
+            ? key.value
+            : obj[key];
+
+        if (skipNulls && value === null) {
+            continue;
+        }
+
+        var encodedKey = allowDots && encodeDotInKeys ? String(key).replace(/\./g, '%2E') : String(key);
+        var keyPrefix = isArray(obj)
+            ? typeof generateArrayPrefix === 'function' ? generateArrayPrefix(adjustedPrefix, encodedKey) : adjustedPrefix
+            : adjustedPrefix + (allowDots ? '.' + encodedKey : '[' + encodedKey + ']');
+
+        sideChannel.set(object, step);
+        var valueSideChannel = getSideChannel();
+        valueSideChannel.set(sentinel, sideChannel);
+        pushToArray(values, stringify(
+            value,
+            keyPrefix,
+            generateArrayPrefix,
+            commaRoundTrip,
+            allowEmptyArrays,
+            strictNullHandling,
+            skipNulls,
+            encodeDotInKeys,
+            generateArrayPrefix === 'comma' && encodeValuesOnly && isArray(obj) ? null : encoder,
+            filter,
+            sort,
+            allowDots,
+            serializeDate,
+            format,
+            formatter,
+            encodeValuesOnly,
+            charset,
+            valueSideChannel
+        ));
+    }
+
+    return values;
+};
+
+var normalizeStringifyOptions = function normalizeStringifyOptions(opts) {
+    if (!opts) {
+        return defaults;
+    }
+
+    if (typeof opts.allowEmptyArrays !== 'undefined' && typeof opts.allowEmptyArrays !== 'boolean') {
+        throw new TypeError('`allowEmptyArrays` option can only be `true` or `false`, when provided');
+    }
+
+    if (typeof opts.encodeDotInKeys !== 'undefined' && typeof opts.encodeDotInKeys !== 'boolean') {
+        throw new TypeError('`encodeDotInKeys` option can only be `true` or `false`, when provided');
+    }
+
+    if (opts.encoder !== null && typeof opts.encoder !== 'undefined' && typeof opts.encoder !== 'function') {
+        throw new TypeError('Encoder has to be a function.');
+    }
+
+    var charset = opts.charset || defaults.charset;
+    if (typeof opts.charset !== 'undefined' && opts.charset !== 'utf-8' && opts.charset !== 'iso-8859-1') {
+        throw new TypeError('The charset option must be either utf-8, iso-8859-1, or undefined');
+    }
+
+    var format = formats['default'];
+    if (typeof opts.format !== 'undefined') {
+        if (!has.call(formats.formatters, opts.format)) {
+            throw new TypeError('Unknown format option provided.');
+        }
+        format = opts.format;
+    }
+    var formatter = formats.formatters[format];
+
+    var filter = defaults.filter;
+    if (typeof opts.filter === 'function' || isArray(opts.filter)) {
+        filter = opts.filter;
+    }
+
+    var arrayFormat;
+    if (opts.arrayFormat in arrayPrefixGenerators) {
+        arrayFormat = opts.arrayFormat;
+    } else if ('indices' in opts) {
+        arrayFormat = opts.indices ? 'indices' : 'repeat';
+    } else {
+        arrayFormat = defaults.arrayFormat;
+    }
+
+    if ('commaRoundTrip' in opts && typeof opts.commaRoundTrip !== 'boolean') {
+        throw new TypeError('`commaRoundTrip` must be a boolean, or absent');
+    }
+
+    var allowDots = typeof opts.allowDots === 'undefined' ? opts.encodeDotInKeys === true ? true : defaults.allowDots : !!opts.allowDots;
+
+    return {
+        addQueryPrefix: typeof opts.addQueryPrefix === 'boolean' ? opts.addQueryPrefix : defaults.addQueryPrefix,
+        allowDots: allowDots,
+        allowEmptyArrays: typeof opts.allowEmptyArrays === 'boolean' ? !!opts.allowEmptyArrays : defaults.allowEmptyArrays,
+        arrayFormat: arrayFormat,
+        charset: charset,
+        charsetSentinel: typeof opts.charsetSentinel === 'boolean' ? opts.charsetSentinel : defaults.charsetSentinel,
+        commaRoundTrip: !!opts.commaRoundTrip,
+        delimiter: typeof opts.delimiter === 'undefined' ? defaults.delimiter : opts.delimiter,
+        encode: typeof opts.encode === 'boolean' ? opts.encode : defaults.encode,
+        encodeDotInKeys: typeof opts.encodeDotInKeys === 'boolean' ? opts.encodeDotInKeys : defaults.encodeDotInKeys,
+        encoder: typeof opts.encoder === 'function' ? opts.encoder : defaults.encoder,
+        encodeValuesOnly: typeof opts.encodeValuesOnly === 'boolean' ? opts.encodeValuesOnly : defaults.encodeValuesOnly,
+        filter: filter,
+        format: format,
+        formatter: formatter,
+        serializeDate: typeof opts.serializeDate === 'function' ? opts.serializeDate : defaults.serializeDate,
+        skipNulls: typeof opts.skipNulls === 'boolean' ? opts.skipNulls : defaults.skipNulls,
+        sort: typeof opts.sort === 'function' ? opts.sort : null,
+        strictNullHandling: typeof opts.strictNullHandling === 'boolean' ? opts.strictNullHandling : defaults.strictNullHandling
+    };
+};
+
+module.exports = function (object, opts) {
+    var obj = object;
+    var options = normalizeStringifyOptions(opts);
+
+    var objKeys;
+    var filter;
+
+    if (typeof options.filter === 'function') {
+        filter = options.filter;
+        obj = filter('', obj);
+    } else if (isArray(options.filter)) {
+        filter = options.filter;
+        objKeys = filter;
+    }
+
+    var keys = [];
+
+    if (typeof obj !== 'object' || obj === null) {
+        return '';
+    }
+
+    var generateArrayPrefix = arrayPrefixGenerators[options.arrayFormat];
+    var commaRoundTrip = generateArrayPrefix === 'comma' && options.commaRoundTrip;
+
+    if (!objKeys) {
+        objKeys = Object.keys(obj);
+    }
+
+    if (options.sort) {
+        objKeys.sort(options.sort);
+    }
+
+    var sideChannel = getSideChannel();
+    for (var i = 0; i < objKeys.length; ++i) {
+        var key = objKeys[i];
+        var value = obj[key];
+
+        if (options.skipNulls && value === null) {
+            continue;
+        }
+        pushToArray(keys, stringify(
+            value,
+            key,
+            generateArrayPrefix,
+            commaRoundTrip,
+            options.allowEmptyArrays,
+            options.strictNullHandling,
+            options.skipNulls,
+            options.encodeDotInKeys,
+            options.encode ? options.encoder : null,
+            options.filter,
+            options.sort,
+            options.allowDots,
+            options.serializeDate,
+            options.format,
+            options.formatter,
+            options.encodeValuesOnly,
+            options.charset,
+            sideChannel
+        ));
+    }
+
+    var joined = keys.join(options.delimiter);
+    var prefix = options.addQueryPrefix === true ? '?' : '';
+
+    if (options.charsetSentinel) {
+        if (options.charset === 'iso-8859-1') {
+            // encodeURIComponent('✓'), the "numeric entity" representation of a checkmark
+            prefix += 'utf8=%26%2310003%3B&';
+        } else {
+            // encodeURIComponent('✓')
+            prefix += 'utf8=%E2%9C%93&';
+        }
+    }
+
+    return joined.length > 0 ? prefix + joined : '';
+};
diff --git a/server/node_modules/qs/lib/utils.js b/server/node_modules/qs/lib/utils.js
new file mode 100644
index 0000000..91f555e
--- /dev/null
+++ b/server/node_modules/qs/lib/utils.js
@@ -0,0 +1,320 @@
+'use strict';
+
+var formats = require('./formats');
+var getSideChannel = require('side-channel');
+
+var has = Object.prototype.hasOwnProperty;
+var isArray = Array.isArray;
+
+// Track objects created from arrayLimit overflow using side-channel
+// Stores the current max numeric index for O(1) lookup
+var overflowChannel = getSideChannel();
+
+var markOverflow = function markOverflow(obj, maxIndex) {
+    overflowChannel.set(obj, maxIndex);
+    return obj;
+};
+
+var isOverflow = function isOverflow(obj) {
+    return overflowChannel.has(obj);
+};
+
+var getMaxIndex = function getMaxIndex(obj) {
+    return overflowChannel.get(obj);
+};
+
+var setMaxIndex = function setMaxIndex(obj, maxIndex) {
+    overflowChannel.set(obj, maxIndex);
+};
+
+var hexTable = (function () {
+    var array = [];
+    for (var i = 0; i < 256; ++i) {
+        array.push('%' + ((i < 16 ? '0' : '') + i.toString(16)).toUpperCase());
+    }
+
+    return array;
+}());
+
+var compactQueue = function compactQueue(queue) {
+    while (queue.length > 1) {
+        var item = queue.pop();
+        var obj = item.obj[item.prop];
+
+        if (isArray(obj)) {
+            var compacted = [];
+
+            for (var j = 0; j < obj.length; ++j) {
+                if (typeof obj[j] !== 'undefined') {
+                    compacted.push(obj[j]);
+                }
+            }
+
+            item.obj[item.prop] = compacted;
+        }
+    }
+};
+
+var arrayToObject = function arrayToObject(source, options) {
+    var obj = options && options.plainObjects ? { __proto__: null } : {};
+    for (var i = 0; i < source.length; ++i) {
+        if (typeof source[i] !== 'undefined') {
+            obj[i] = source[i];
+        }
+    }
+
+    return obj;
+};
+
+var merge = function merge(target, source, options) {
+    /* eslint no-param-reassign: 0 */
+    if (!source) {
+        return target;
+    }
+
+    if (typeof source !== 'object' && typeof source !== 'function') {
+        if (isArray(target)) {
+            target.push(source);
+        } else if (target && typeof target === 'object') {
+            if (isOverflow(target)) {
+                // Add at next numeric index for overflow objects
+                var newIndex = getMaxIndex(target) + 1;
+                target[newIndex] = source;
+                setMaxIndex(target, newIndex);
+            } else if (
+                (options && (options.plainObjects || options.allowPrototypes))
+                || !has.call(Object.prototype, source)
+            ) {
+                target[source] = true;
+            }
+        } else {
+            return [target, source];
+        }
+
+        return target;
+    }
+
+    if (!target || typeof target !== 'object') {
+        if (isOverflow(source)) {
+            // Create new object with target at 0, source values shifted by 1
+            var sourceKeys = Object.keys(source);
+            var result = options && options.plainObjects
+                ? { __proto__: null, 0: target }
+                : { 0: target };
+            for (var m = 0; m < sourceKeys.length; m++) {
+                var oldKey = parseInt(sourceKeys[m], 10);
+                result[oldKey + 1] = source[sourceKeys[m]];
+            }
+            return markOverflow(result, getMaxIndex(source) + 1);
+        }
+        return [target].concat(source);
+    }
+
+    var mergeTarget = target;
+    if (isArray(target) && !isArray(source)) {
+        mergeTarget = arrayToObject(target, options);
+    }
+
+    if (isArray(target) && isArray(source)) {
+        source.forEach(function (item, i) {
+            if (has.call(target, i)) {
+                var targetItem = target[i];
+                if (targetItem && typeof targetItem === 'object' && item && typeof item === 'object') {
+                    target[i] = merge(targetItem, item, options);
+                } else {
+                    target.push(item);
+                }
+            } else {
+                target[i] = item;
+            }
+        });
+        return target;
+    }
+
+    return Object.keys(source).reduce(function (acc, key) {
+        var value = source[key];
+
+        if (has.call(acc, key)) {
+            acc[key] = merge(acc[key], value, options);
+        } else {
+            acc[key] = value;
+        }
+        return acc;
+    }, mergeTarget);
+};
+
+var assign = function assignSingleSource(target, source) {
+    return Object.keys(source).reduce(function (acc, key) {
+        acc[key] = source[key];
+        return acc;
+    }, target);
+};
+
+var decode = function (str, defaultDecoder, charset) {
+    var strWithoutPlus = str.replace(/\+/g, ' ');
+    if (charset === 'iso-8859-1') {
+        // unescape never throws, no try...catch needed:
+        return strWithoutPlus.replace(/%[0-9a-f]{2}/gi, unescape);
+    }
+    // utf-8
+    try {
+        return decodeURIComponent(strWithoutPlus);
+    } catch (e) {
+        return strWithoutPlus;
+    }
+};
+
+var limit = 1024;
+
+/* eslint operator-linebreak: [2, "before"] */
+
+var encode = function encode(str, defaultEncoder, charset, kind, format) {
+    // This code was originally written by Brian White (mscdex) for the io.js core querystring library.
+    // It has been adapted here for stricter adherence to RFC 3986
+    if (str.length === 0) {
+        return str;
+    }
+
+    var string = str;
+    if (typeof str === 'symbol') {
+        string = Symbol.prototype.toString.call(str);
+    } else if (typeof str !== 'string') {
+        string = String(str);
+    }
+
+    if (charset === 'iso-8859-1') {
+        return escape(string).replace(/%u[0-9a-f]{4}/gi, function ($0) {
+            return '%26%23' + parseInt($0.slice(2), 16) + '%3B';
+        });
+    }
+
+    var out = '';
+    for (var j = 0; j < string.length; j += limit) {
+        var segment = string.length >= limit ? string.slice(j, j + limit) : string;
+        var arr = [];
+
+        for (var i = 0; i < segment.length; ++i) {
+            var c = segment.charCodeAt(i);
+            if (
+                c === 0x2D // -
+                || c === 0x2E // .
+                || c === 0x5F // _
+                || c === 0x7E // ~
+                || (c >= 0x30 && c <= 0x39) // 0-9
+                || (c >= 0x41 && c <= 0x5A) // a-z
+                || (c >= 0x61 && c <= 0x7A) // A-Z
+                || (format === formats.RFC1738 && (c === 0x28 || c === 0x29)) // ( )
+            ) {
+                arr[arr.length] = segment.charAt(i);
+                continue;
+            }
+
+            if (c < 0x80) {
+                arr[arr.length] = hexTable[c];
+                continue;
+            }
+
+            if (c < 0x800) {
+                arr[arr.length] = hexTable[0xC0 | (c >> 6)]
+                    + hexTable[0x80 | (c & 0x3F)];
+                continue;
+            }
+
+            if (c < 0xD800 || c >= 0xE000) {
+                arr[arr.length] = hexTable[0xE0 | (c >> 12)]
+                    + hexTable[0x80 | ((c >> 6) & 0x3F)]
+                    + hexTable[0x80 | (c & 0x3F)];
+                continue;
+            }
+
+            i += 1;
+            c = 0x10000 + (((c & 0x3FF) << 10) | (segment.charCodeAt(i) & 0x3FF));
+
+            arr[arr.length] = hexTable[0xF0 | (c >> 18)]
+                + hexTable[0x80 | ((c >> 12) & 0x3F)]
+                + hexTable[0x80 | ((c >> 6) & 0x3F)]
+                + hexTable[0x80 | (c & 0x3F)];
+        }
+
+        out += arr.join('');
+    }
+
+    return out;
+};
+
+var compact = function compact(value) {
+    var queue = [{ obj: { o: value }, prop: 'o' }];
+    var refs = [];
+
+    for (var i = 0; i < queue.length; ++i) {
+        var item = queue[i];
+        var obj = item.obj[item.prop];
+
+        var keys = Object.keys(obj);
+        for (var j = 0; j < keys.length; ++j) {
+            var key = keys[j];
+            var val = obj[key];
+            if (typeof val === 'object' && val !== null && refs.indexOf(val) === -1) {
+                queue.push({ obj: obj, prop: key });
+                refs.push(val);
+            }
+        }
+    }
+
+    compactQueue(queue);
+
+    return value;
+};
+
+var isRegExp = function isRegExp(obj) {
+    return Object.prototype.toString.call(obj) === '[object RegExp]';
+};
+
+var isBuffer = function isBuffer(obj) {
+    if (!obj || typeof obj !== 'object') {
+        return false;
+    }
+
+    return !!(obj.constructor && obj.constructor.isBuffer && obj.constructor.isBuffer(obj));
+};
+
+var combine = function combine(a, b, arrayLimit, plainObjects) {
+    // If 'a' is already an overflow object, add to it
+    if (isOverflow(a)) {
+        var newIndex = getMaxIndex(a) + 1;
+        a[newIndex] = b;
+        setMaxIndex(a, newIndex);
+        return a;
+    }
+
+    var result = [].concat(a, b);
+    if (result.length > arrayLimit) {
+        return markOverflow(arrayToObject(result, { plainObjects: plainObjects }), result.length - 1);
+    }
+    return result;
+};
+
+var maybeMap = function maybeMap(val, fn) {
+    if (isArray(val)) {
+        var mapped = [];
+        for (var i = 0; i < val.length; i += 1) {
+            mapped.push(fn(val[i]));
+        }
+        return mapped;
+    }
+    return fn(val);
+};
+
+module.exports = {
+    arrayToObject: arrayToObject,
+    assign: assign,
+    combine: combine,
+    compact: compact,
+    decode: decode,
+    encode: encode,
+    isBuffer: isBuffer,
+    isOverflow: isOverflow,
+    isRegExp: isRegExp,
+    maybeMap: maybeMap,
+    merge: merge
+};
diff --git a/server/node_modules/qs/package.json b/server/node_modules/qs/package.json
new file mode 100644
index 0000000..e4875e4
--- /dev/null
+++ b/server/node_modules/qs/package.json
@@ -0,0 +1,94 @@
+{
+    "name": "qs",
+    "description": "A querystring parser that supports nesting and arrays, with a depth limit",
+    "homepage": "https://github.com/ljharb/qs",
+    "version": "6.14.1",
+    "repository": {
+        "type": "git",
+        "url": "https://github.com/ljharb/qs.git"
+    },
+    "funding": {
+        "url": "https://github.com/sponsors/ljharb"
+    },
+    "main": "lib/index.js",
+    "sideEffects": false,
+    "contributors": [
+        {
+            "name": "Jordan Harband",
+            "email": "ljharb@gmail.com",
+            "url": "http://ljharb.codes"
+        }
+    ],
+    "keywords": [
+        "querystring",
+        "qs",
+        "query",
+        "url",
+        "parse",
+        "stringify"
+    ],
+    "engines": {
+        "node": ">=0.6"
+    },
+    "dependencies": {
+        "side-channel": "^1.1.0"
+    },
+    "devDependencies": {
+        "@browserify/envify": "^6.0.0",
+        "@browserify/uglifyify": "^6.0.0",
+        "@ljharb/eslint-config": "^22.1.3",
+        "browserify": "^16.5.2",
+        "bundle-collapser": "^1.4.0",
+        "common-shakeify": "~1.0.0",
+        "eclint": "^2.8.1",
+        "es-value-fixtures": "^1.7.1",
+        "eslint": "^9.39.2",
+        "evalmd": "^0.0.19",
+        "for-each": "^0.3.5",
+        "glob": "=10.3.7",
+        "has-bigints": "^1.1.0",
+        "has-override-mistake": "^1.0.1",
+        "has-property-descriptors": "^1.0.2",
+        "has-proto": "^1.2.0",
+        "has-symbols": "^1.1.0",
+        "iconv-lite": "^0.5.1",
+        "in-publish": "^2.0.1",
+        "jackspeak": "=2.1.1",
+        "jiti": "^0.0.0",
+        "mkdirp": "^0.5.5",
+        "mock-property": "^1.1.0",
+        "module-deps": "^6.2.3",
+        "npmignore": "^0.3.5",
+        "nyc": "^10.3.2",
+        "object-inspect": "^1.13.4",
+        "qs-iconv": "^1.0.4",
+        "safe-publish-latest": "^2.0.0",
+        "safer-buffer": "^2.1.2",
+        "tape": "^5.9.0",
+        "unassertify": "^3.0.1"
+    },
+    "scripts": {
+        "prepack": "npmignore --auto --commentLines=autogenerated && npm run dist",
+        "prepublishOnly": "safe-publish-latest",
+        "prepublish": "not-in-publish || npm run prepublishOnly",
+        "pretest": "npm run --silent readme && npm run --silent lint",
+        "test": "npm run tests-only",
+        "tests-only": "nyc tape 'test/**/*.js'",
+        "posttest": "npx npm@'>=10.2' audit --production",
+        "readme": "evalmd README.md",
+        "postlint": "eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git' | grep -v dist/)",
+        "lint": "eslint .",
+        "dist": "mkdirp dist && browserify --standalone Qs -g unassertify -g @browserify/envify -g [@browserify/uglifyify --mangle.keep_fnames --compress.keep_fnames --format.indent_level=1 --compress.arrows=false --compress.passes=4 --compress.typeofs=false] -p common-shakeify -p bundle-collapser/plugin lib/index.js > dist/qs.js"
+    },
+    "license": "BSD-3-Clause",
+    "publishConfig": {
+        "ignore": [
+            "!dist/*",
+            "bower.json",
+            "component.json",
+            ".github/workflows",
+            "logos",
+            "tea.yaml"
+        ]
+    }
+}
diff --git a/server/node_modules/qs/test/empty-keys-cases.js b/server/node_modules/qs/test/empty-keys-cases.js
new file mode 100644
index 0000000..2b1190e
--- /dev/null
+++ b/server/node_modules/qs/test/empty-keys-cases.js
@@ -0,0 +1,267 @@
+'use strict';
+
+module.exports = {
+    emptyTestCases: [
+        {
+            input: '&',
+            withEmptyKeys: {},
+            stringifyOutput: {
+                brackets: '',
+                indices: '',
+                repeat: ''
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '&&',
+            withEmptyKeys: {},
+            stringifyOutput: {
+                brackets: '',
+                indices: '',
+                repeat: ''
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '&=',
+            withEmptyKeys: { '': '' },
+            stringifyOutput: {
+                brackets: '=',
+                indices: '=',
+                repeat: '='
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '&=&',
+            withEmptyKeys: { '': '' },
+            stringifyOutput: {
+                brackets: '=',
+                indices: '=',
+                repeat: '='
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '&=&=',
+            withEmptyKeys: { '': ['', ''] },
+            stringifyOutput: {
+                brackets: '[]=&[]=',
+                indices: '[0]=&[1]=',
+                repeat: '=&='
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '&=&=&',
+            withEmptyKeys: { '': ['', ''] },
+            stringifyOutput: {
+                brackets: '[]=&[]=',
+                indices: '[0]=&[1]=',
+                repeat: '=&='
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '=',
+            withEmptyKeys: { '': '' },
+            noEmptyKeys: {},
+            stringifyOutput: {
+                brackets: '=',
+                indices: '=',
+                repeat: '='
+            }
+        },
+        {
+            input: '=&',
+            withEmptyKeys: { '': '' },
+            stringifyOutput: {
+                brackets: '=',
+                indices: '=',
+                repeat: '='
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '=&&&',
+            withEmptyKeys: { '': '' },
+            stringifyOutput: {
+                brackets: '=',
+                indices: '=',
+                repeat: '='
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '=&=&=&',
+            withEmptyKeys: { '': ['', '', ''] },
+            stringifyOutput: {
+                brackets: '[]=&[]=&[]=',
+                indices: '[0]=&[1]=&[2]=',
+                repeat: '=&=&='
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '=&a[]=b&a[1]=c',
+            withEmptyKeys: { '': '', a: ['b', 'c'] },
+            stringifyOutput: {
+                brackets: '=&a[]=b&a[]=c',
+                indices: '=&a[0]=b&a[1]=c',
+                repeat: '=&a=b&a=c'
+            },
+            noEmptyKeys: { a: ['b', 'c'] }
+        },
+        {
+            input: '=a',
+            withEmptyKeys: { '': 'a' },
+            noEmptyKeys: {},
+            stringifyOutput: {
+                brackets: '=a',
+                indices: '=a',
+                repeat: '=a'
+            }
+        },
+        {
+            input: 'a==a',
+            withEmptyKeys: { a: '=a' },
+            noEmptyKeys: { a: '=a' },
+            stringifyOutput: {
+                brackets: 'a==a',
+                indices: 'a==a',
+                repeat: 'a==a'
+            }
+        },
+        {
+            input: '=&a[]=b',
+            withEmptyKeys: { '': '', a: ['b'] },
+            stringifyOutput: {
+                brackets: '=&a[]=b',
+                indices: '=&a[0]=b',
+                repeat: '=&a=b'
+            },
+            noEmptyKeys: { a: ['b'] }
+        },
+        {
+            input: '=&a[]=b&a[]=c&a[2]=d',
+            withEmptyKeys: { '': '', a: ['b', 'c', 'd'] },
+            stringifyOutput: {
+                brackets: '=&a[]=b&a[]=c&a[]=d',
+                indices: '=&a[0]=b&a[1]=c&a[2]=d',
+                repeat: '=&a=b&a=c&a=d'
+            },
+            noEmptyKeys: { a: ['b', 'c', 'd'] }
+        },
+        {
+            input: '=a&=b',
+            withEmptyKeys: { '': ['a', 'b'] },
+            stringifyOutput: {
+                brackets: '[]=a&[]=b',
+                indices: '[0]=a&[1]=b',
+                repeat: '=a&=b'
+            },
+            noEmptyKeys: {}
+        },
+        {
+            input: '=a&foo=b',
+            withEmptyKeys: { '': 'a', foo: 'b' },
+            noEmptyKeys: { foo: 'b' },
+            stringifyOutput: {
+                brackets: '=a&foo=b',
+                indices: '=a&foo=b',
+                repeat: '=a&foo=b'
+            }
+        },
+        {
+            input: 'a[]=b&a=c&=',
+            withEmptyKeys: { '': '', a: ['b', 'c'] },
+            stringifyOutput: {
+                brackets: '=&a[]=b&a[]=c',
+                indices: '=&a[0]=b&a[1]=c',
+                repeat: '=&a=b&a=c'
+            },
+            noEmptyKeys: { a: ['b', 'c'] }
+        },
+        {
+            input: 'a[]=b&a=c&=',
+            withEmptyKeys: { '': '', a: ['b', 'c'] },
+            stringifyOutput: {
+                brackets: '=&a[]=b&a[]=c',
+                indices: '=&a[0]=b&a[1]=c',
+                repeat: '=&a=b&a=c'
+            },
+            noEmptyKeys: { a: ['b', 'c'] }
+        },
+        {
+            input: 'a[0]=b&a=c&=',
+            withEmptyKeys: { '': '', a: ['b', 'c'] },
+            stringifyOutput: {
+                brackets: '=&a[]=b&a[]=c',
+                indices: '=&a[0]=b&a[1]=c',
+                repeat: '=&a=b&a=c'
+            },
+            noEmptyKeys: { a: ['b', 'c'] }
+        },
+        {
+            input: 'a=b&a[]=c&=',
+            withEmptyKeys: { '': '', a: ['b', 'c'] },
+            stringifyOutput: {
+                brackets: '=&a[]=b&a[]=c',
+                indices: '=&a[0]=b&a[1]=c',
+                repeat: '=&a=b&a=c'
+            },
+            noEmptyKeys: { a: ['b', 'c'] }
+        },
+        {
+            input: 'a=b&a[0]=c&=',
+            withEmptyKeys: { '': '', a: ['b', 'c'] },
+            stringifyOutput: {
+                brackets: '=&a[]=b&a[]=c',
+                indices: '=&a[0]=b&a[1]=c',
+                repeat: '=&a=b&a=c'
+            },
+            noEmptyKeys: { a: ['b', 'c'] }
+        },
+        {
+            input: '[]=a&[]=b& []=1',
+            withEmptyKeys: { '': ['a', 'b'], ' ': ['1'] },
+            stringifyOutput: {
+                brackets: '[]=a&[]=b& []=1',
+                indices: '[0]=a&[1]=b& [0]=1',
+                repeat: '=a&=b& =1'
+            },
+            noEmptyKeys: { 0: 'a', 1: 'b', ' ': ['1'] }
+        },
+        {
+            input: '[0]=a&[1]=b&a[0]=1&a[1]=2',
+            withEmptyKeys: { '': ['a', 'b'], a: ['1', '2'] },
+            noEmptyKeys: { 0: 'a', 1: 'b', a: ['1', '2'] },
+            stringifyOutput: {
+                brackets: '[]=a&[]=b&a[]=1&a[]=2',
+                indices: '[0]=a&[1]=b&a[0]=1&a[1]=2',
+                repeat: '=a&=b&a=1&a=2'
+            }
+        },
+        {
+            input: '[deep]=a&[deep]=2',
+            withEmptyKeys: { '': { deep: ['a', '2'] }
+            },
+            stringifyOutput: {
+                brackets: '[deep][]=a&[deep][]=2',
+                indices: '[deep][0]=a&[deep][1]=2',
+                repeat: '[deep]=a&[deep]=2'
+            },
+            noEmptyKeys: { deep: ['a', '2'] }
+        },
+        {
+            input: '%5B0%5D=a&%5B1%5D=b',
+            withEmptyKeys: { '': ['a', 'b'] },
+            stringifyOutput: {
+                brackets: '[]=a&[]=b',
+                indices: '[0]=a&[1]=b',
+                repeat: '=a&=b'
+            },
+            noEmptyKeys: { 0: 'a', 1: 'b' }
+        }
+    ]
+};
diff --git a/server/node_modules/qs/test/parse.js b/server/node_modules/qs/test/parse.js
new file mode 100644
index 0000000..7b353ff
--- /dev/null
+++ b/server/node_modules/qs/test/parse.js
@@ -0,0 +1,1396 @@
+'use strict';
+
+var test = require('tape');
+var hasPropertyDescriptors = require('has-property-descriptors')();
+var iconv = require('iconv-lite');
+var mockProperty = require('mock-property');
+var hasOverrideMistake = require('has-override-mistake')();
+var SaferBuffer = require('safer-buffer').Buffer;
+var v = require('es-value-fixtures');
+var inspect = require('object-inspect');
+var emptyTestCases = require('./empty-keys-cases').emptyTestCases;
+var hasProto = require('has-proto')();
+
+var qs = require('../');
+var utils = require('../lib/utils');
+
+test('parse()', function (t) {
+    t.test('parses a simple string', function (st) {
+        st.deepEqual(qs.parse('0=foo'), { 0: 'foo' });
+        st.deepEqual(qs.parse('foo=c++'), { foo: 'c  ' });
+        st.deepEqual(qs.parse('a[>=]=23'), { a: { '>=': '23' } });
+        st.deepEqual(qs.parse('a[<=>]==23'), { a: { '<=>': '=23' } });
+        st.deepEqual(qs.parse('a[==]=23'), { a: { '==': '23' } });
+        st.deepEqual(qs.parse('foo', { strictNullHandling: true }), { foo: null });
+        st.deepEqual(qs.parse('foo'), { foo: '' });
+        st.deepEqual(qs.parse('foo='), { foo: '' });
+        st.deepEqual(qs.parse('foo=bar'), { foo: 'bar' });
+        st.deepEqual(qs.parse(' foo = bar = baz '), { ' foo ': ' bar = baz ' });
+        st.deepEqual(qs.parse('foo=bar=baz'), { foo: 'bar=baz' });
+        st.deepEqual(qs.parse('foo=bar&bar=baz'), { foo: 'bar', bar: 'baz' });
+        st.deepEqual(qs.parse('foo2=bar2&baz2='), { foo2: 'bar2', baz2: '' });
+        st.deepEqual(qs.parse('foo=bar&baz', { strictNullHandling: true }), { foo: 'bar', baz: null });
+        st.deepEqual(qs.parse('foo=bar&baz'), { foo: 'bar', baz: '' });
+        st.deepEqual(qs.parse('cht=p3&chd=t:60,40&chs=250x100&chl=Hello|World'), {
+            cht: 'p3',
+            chd: 't:60,40',
+            chs: '250x100',
+            chl: 'Hello|World'
+        });
+        st.end();
+    });
+
+    t.test('comma: false', function (st) {
+        st.deepEqual(qs.parse('a[]=b&a[]=c'), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a[0]=b&a[1]=c'), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a=b,c'), { a: 'b,c' });
+        st.deepEqual(qs.parse('a=b&a=c'), { a: ['b', 'c'] });
+        st.end();
+    });
+
+    t.test('comma: true', function (st) {
+        st.deepEqual(qs.parse('a[]=b&a[]=c', { comma: true }), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a[0]=b&a[1]=c', { comma: true }), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a=b,c', { comma: true }), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a=b&a=c', { comma: true }), { a: ['b', 'c'] });
+        st.end();
+    });
+
+    t.test('allows enabling dot notation', function (st) {
+        st.deepEqual(qs.parse('a.b=c'), { 'a.b': 'c' });
+        st.deepEqual(qs.parse('a.b=c', { allowDots: true }), { a: { b: 'c' } });
+
+        st.end();
+    });
+
+    t.test('decode dot keys correctly', function (st) {
+        st.deepEqual(
+            qs.parse('name%252Eobj.first=John&name%252Eobj.last=Doe', { allowDots: false, decodeDotInKeys: false }),
+            { 'name%2Eobj.first': 'John', 'name%2Eobj.last': 'Doe' },
+            'with allowDots false and decodeDotInKeys false'
+        );
+        st.deepEqual(
+            qs.parse('name.obj.first=John&name.obj.last=Doe', { allowDots: true, decodeDotInKeys: false }),
+            { name: { obj: { first: 'John', last: 'Doe' } } },
+            'with allowDots false and decodeDotInKeys false'
+        );
+        st.deepEqual(
+            qs.parse('name%252Eobj.first=John&name%252Eobj.last=Doe', { allowDots: true, decodeDotInKeys: false }),
+            { 'name%2Eobj': { first: 'John', last: 'Doe' } },
+            'with allowDots true and decodeDotInKeys false'
+        );
+        st.deepEqual(
+            qs.parse('name%252Eobj.first=John&name%252Eobj.last=Doe', { allowDots: true, decodeDotInKeys: true }),
+            { 'name.obj': { first: 'John', last: 'Doe' } },
+            'with allowDots true and decodeDotInKeys true'
+        );
+
+        st.deepEqual(
+            qs.parse(
+                'name%252Eobj%252Esubobject.first%252Egodly%252Ename=John&name%252Eobj%252Esubobject.last=Doe',
+                { allowDots: false, decodeDotInKeys: false }
+            ),
+            { 'name%2Eobj%2Esubobject.first%2Egodly%2Ename': 'John', 'name%2Eobj%2Esubobject.last': 'Doe' },
+            'with allowDots false and decodeDotInKeys false'
+        );
+        st.deepEqual(
+            qs.parse(
+                'name.obj.subobject.first.godly.name=John&name.obj.subobject.last=Doe',
+                { allowDots: true, decodeDotInKeys: false }
+            ),
+            { name: { obj: { subobject: { first: { godly: { name: 'John' } }, last: 'Doe' } } } },
+            'with allowDots true and decodeDotInKeys false'
+        );
+        st.deepEqual(
+            qs.parse(
+                'name%252Eobj%252Esubobject.first%252Egodly%252Ename=John&name%252Eobj%252Esubobject.last=Doe',
+                { allowDots: true, decodeDotInKeys: true }
+            ),
+            { 'name.obj.subobject': { 'first.godly.name': 'John', last: 'Doe' } },
+            'with allowDots true and decodeDotInKeys true'
+        );
+        st.deepEqual(
+            qs.parse('name%252Eobj.first=John&name%252Eobj.last=Doe'),
+            { 'name%2Eobj.first': 'John', 'name%2Eobj.last': 'Doe' },
+            'with allowDots and decodeDotInKeys undefined'
+        );
+
+        st.end();
+    });
+
+    t.test('decodes dot in key of object, and allow enabling dot notation when decodeDotInKeys is set to true and allowDots is undefined', function (st) {
+        st.deepEqual(
+            qs.parse(
+                'name%252Eobj%252Esubobject.first%252Egodly%252Ename=John&name%252Eobj%252Esubobject.last=Doe',
+                { decodeDotInKeys: true }
+            ),
+            { 'name.obj.subobject': { 'first.godly.name': 'John', last: 'Doe' } },
+            'with allowDots undefined and decodeDotInKeys true'
+        );
+
+        st.end();
+    });
+
+    t.test('throws when decodeDotInKeys is not of type boolean', function (st) {
+        st['throws'](
+            function () { qs.parse('foo[]&bar=baz', { decodeDotInKeys: 'foobar' }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.parse('foo[]&bar=baz', { decodeDotInKeys: 0 }); },
+            TypeError
+        );
+        st['throws'](
+            function () { qs.parse('foo[]&bar=baz', { decodeDotInKeys: NaN }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.parse('foo[]&bar=baz', { decodeDotInKeys: null }); },
+            TypeError
+        );
+
+        st.end();
+    });
+
+    t.test('allows empty arrays in obj values', function (st) {
+        st.deepEqual(qs.parse('foo[]&bar=baz', { allowEmptyArrays: true }), { foo: [], bar: 'baz' });
+        st.deepEqual(qs.parse('foo[]&bar=baz', { allowEmptyArrays: false }), { foo: [''], bar: 'baz' });
+
+        st.end();
+    });
+
+    t.test('throws when allowEmptyArrays is not of type boolean', function (st) {
+        st['throws'](
+            function () { qs.parse('foo[]&bar=baz', { allowEmptyArrays: 'foobar' }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.parse('foo[]&bar=baz', { allowEmptyArrays: 0 }); },
+            TypeError
+        );
+        st['throws'](
+            function () { qs.parse('foo[]&bar=baz', { allowEmptyArrays: NaN }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.parse('foo[]&bar=baz', { allowEmptyArrays: null }); },
+            TypeError
+        );
+
+        st.end();
+    });
+
+    t.test('allowEmptyArrays + strictNullHandling', function (st) {
+        st.deepEqual(
+            qs.parse('testEmptyArray[]', { strictNullHandling: true, allowEmptyArrays: true }),
+            { testEmptyArray: [] }
+        );
+
+        st.end();
+    });
+
+    t.deepEqual(qs.parse('a[b]=c'), { a: { b: 'c' } }, 'parses a single nested string');
+    t.deepEqual(qs.parse('a[b][c]=d'), { a: { b: { c: 'd' } } }, 'parses a double nested string');
+    t.deepEqual(
+        qs.parse('a[b][c][d][e][f][g][h]=i'),
+        { a: { b: { c: { d: { e: { f: { '[g][h]': 'i' } } } } } } },
+        'defaults to a depth of 5'
+    );
+
+    t.test('only parses one level when depth = 1', function (st) {
+        st.deepEqual(qs.parse('a[b][c]=d', { depth: 1 }), { a: { b: { '[c]': 'd' } } });
+        st.deepEqual(qs.parse('a[b][c][d]=e', { depth: 1 }), { a: { b: { '[c][d]': 'e' } } });
+        st.end();
+    });
+
+    t.test('uses original key when depth = 0', function (st) {
+        st.deepEqual(qs.parse('a[0]=b&a[1]=c', { depth: 0 }), { 'a[0]': 'b', 'a[1]': 'c' });
+        st.deepEqual(qs.parse('a[0][0]=b&a[0][1]=c&a[1]=d&e=2', { depth: 0 }), { 'a[0][0]': 'b', 'a[0][1]': 'c', 'a[1]': 'd', e: '2' });
+        st.end();
+    });
+
+    t.test('uses original key when depth = false', function (st) {
+        st.deepEqual(qs.parse('a[0]=b&a[1]=c', { depth: false }), { 'a[0]': 'b', 'a[1]': 'c' });
+        st.deepEqual(qs.parse('a[0][0]=b&a[0][1]=c&a[1]=d&e=2', { depth: false }), { 'a[0][0]': 'b', 'a[0][1]': 'c', 'a[1]': 'd', e: '2' });
+        st.end();
+    });
+
+    t.deepEqual(qs.parse('a=b&a=c'), { a: ['b', 'c'] }, 'parses a simple array');
+
+    t.test('parses an explicit array', function (st) {
+        st.deepEqual(qs.parse('a[]=b'), { a: ['b'] });
+        st.deepEqual(qs.parse('a[]=b&a[]=c'), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a[]=b&a[]=c&a[]=d'), { a: ['b', 'c', 'd'] });
+        st.end();
+    });
+
+    t.test('parses a mix of simple and explicit arrays', function (st) {
+        st.deepEqual(qs.parse('a=b&a[]=c'), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a[]=b&a=c'), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a[0]=b&a=c'), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a=b&a[0]=c'), { a: ['b', 'c'] });
+
+        st.deepEqual(qs.parse('a[1]=b&a=c', { arrayLimit: 20 }), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a[]=b&a=c', { arrayLimit: 0 }), { a: { 0: 'b', 1: 'c' } });
+        st.deepEqual(qs.parse('a[]=b&a=c'), { a: ['b', 'c'] });
+
+        st.deepEqual(qs.parse('a=b&a[1]=c', { arrayLimit: 20 }), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a=b&a[]=c', { arrayLimit: 0 }), { a: { 0: 'b', 1: 'c' } });
+        st.deepEqual(qs.parse('a=b&a[]=c'), { a: ['b', 'c'] });
+
+        st.end();
+    });
+
+    t.test('parses a nested array', function (st) {
+        st.deepEqual(qs.parse('a[b][]=c&a[b][]=d'), { a: { b: ['c', 'd'] } });
+        st.deepEqual(qs.parse('a[>=]=25'), { a: { '>=': '25' } });
+        st.end();
+    });
+
+    t.test('allows to specify array indices', function (st) {
+        st.deepEqual(qs.parse('a[1]=c&a[0]=b&a[2]=d'), { a: ['b', 'c', 'd'] });
+        st.deepEqual(qs.parse('a[1]=c&a[0]=b'), { a: ['b', 'c'] });
+        st.deepEqual(qs.parse('a[1]=c', { arrayLimit: 20 }), { a: ['c'] });
+        st.deepEqual(qs.parse('a[1]=c', { arrayLimit: 0 }), { a: { 1: 'c' } });
+        st.deepEqual(qs.parse('a[1]=c'), { a: ['c'] });
+        st.end();
+    });
+
+    t.test('limits specific array indices to arrayLimit', function (st) {
+        st.deepEqual(qs.parse('a[20]=a', { arrayLimit: 20 }), { a: ['a'] });
+        st.deepEqual(qs.parse('a[21]=a', { arrayLimit: 20 }), { a: { 21: 'a' } });
+
+        st.deepEqual(qs.parse('a[20]=a'), { a: ['a'] });
+        st.deepEqual(qs.parse('a[21]=a'), { a: { 21: 'a' } });
+        st.end();
+    });
+
+    t.deepEqual(qs.parse('a[12b]=c'), { a: { '12b': 'c' } }, 'supports keys that begin with a number');
+
+    t.test('supports encoded = signs', function (st) {
+        st.deepEqual(qs.parse('he%3Dllo=th%3Dere'), { 'he=llo': 'th=ere' });
+        st.end();
+    });
+
+    t.test('is ok with url encoded strings', function (st) {
+        st.deepEqual(qs.parse('a[b%20c]=d'), { a: { 'b c': 'd' } });
+        st.deepEqual(qs.parse('a[b]=c%20d'), { a: { b: 'c d' } });
+        st.end();
+    });
+
+    t.test('allows brackets in the value', function (st) {
+        st.deepEqual(qs.parse('pets=["tobi"]'), { pets: '["tobi"]' });
+        st.deepEqual(qs.parse('operators=[">=", "<="]'), { operators: '[">=", "<="]' });
+        st.end();
+    });
+
+    t.test('allows empty values', function (st) {
+        st.deepEqual(qs.parse(''), {});
+        st.deepEqual(qs.parse(null), {});
+        st.deepEqual(qs.parse(undefined), {});
+        st.end();
+    });
+
+    t.test('transforms arrays to objects', function (st) {
+        st.deepEqual(qs.parse('foo[0]=bar&foo[bad]=baz'), { foo: { 0: 'bar', bad: 'baz' } });
+        st.deepEqual(qs.parse('foo[bad]=baz&foo[0]=bar'), { foo: { bad: 'baz', 0: 'bar' } });
+        st.deepEqual(qs.parse('foo[bad]=baz&foo[]=bar'), { foo: { bad: 'baz', 0: 'bar' } });
+        st.deepEqual(qs.parse('foo[]=bar&foo[bad]=baz'), { foo: { 0: 'bar', bad: 'baz' } });
+        st.deepEqual(qs.parse('foo[bad]=baz&foo[]=bar&foo[]=foo'), { foo: { bad: 'baz', 0: 'bar', 1: 'foo' } });
+        st.deepEqual(qs.parse('foo[0][a]=a&foo[0][b]=b&foo[1][a]=aa&foo[1][b]=bb'), { foo: [{ a: 'a', b: 'b' }, { a: 'aa', b: 'bb' }] });
+
+        st.deepEqual(qs.parse('a[]=b&a[t]=u&a[hasOwnProperty]=c', { allowPrototypes: false }), { a: { 0: 'b', t: 'u' } });
+        st.deepEqual(qs.parse('a[]=b&a[t]=u&a[hasOwnProperty]=c', { allowPrototypes: true }), { a: { 0: 'b', t: 'u', hasOwnProperty: 'c' } });
+        st.deepEqual(qs.parse('a[]=b&a[hasOwnProperty]=c&a[x]=y', { allowPrototypes: false }), { a: { 0: 'b', x: 'y' } });
+        st.deepEqual(qs.parse('a[]=b&a[hasOwnProperty]=c&a[x]=y', { allowPrototypes: true }), { a: { 0: 'b', hasOwnProperty: 'c', x: 'y' } });
+        st.end();
+    });
+
+    t.test('transforms arrays to objects (dot notation)', function (st) {
+        st.deepEqual(qs.parse('foo[0].baz=bar&fool.bad=baz', { allowDots: true }), { foo: [{ baz: 'bar' }], fool: { bad: 'baz' } });
+        st.deepEqual(qs.parse('foo[0].baz=bar&fool.bad.boo=baz', { allowDots: true }), { foo: [{ baz: 'bar' }], fool: { bad: { boo: 'baz' } } });
+        st.deepEqual(qs.parse('foo[0][0].baz=bar&fool.bad=baz', { allowDots: true }), { foo: [[{ baz: 'bar' }]], fool: { bad: 'baz' } });
+        st.deepEqual(qs.parse('foo[0].baz[0]=15&foo[0].bar=2', { allowDots: true }), { foo: [{ baz: ['15'], bar: '2' }] });
+        st.deepEqual(qs.parse('foo[0].baz[0]=15&foo[0].baz[1]=16&foo[0].bar=2', { allowDots: true }), { foo: [{ baz: ['15', '16'], bar: '2' }] });
+        st.deepEqual(qs.parse('foo.bad=baz&foo[0]=bar', { allowDots: true }), { foo: { bad: 'baz', 0: 'bar' } });
+        st.deepEqual(qs.parse('foo.bad=baz&foo[]=bar', { allowDots: true }), { foo: { bad: 'baz', 0: 'bar' } });
+        st.deepEqual(qs.parse('foo[]=bar&foo.bad=baz', { allowDots: true }), { foo: { 0: 'bar', bad: 'baz' } });
+        st.deepEqual(qs.parse('foo.bad=baz&foo[]=bar&foo[]=foo', { allowDots: true }), { foo: { bad: 'baz', 0: 'bar', 1: 'foo' } });
+        st.deepEqual(qs.parse('foo[0].a=a&foo[0].b=b&foo[1].a=aa&foo[1].b=bb', { allowDots: true }), { foo: [{ a: 'a', b: 'b' }, { a: 'aa', b: 'bb' }] });
+        st.end();
+    });
+
+    t.test('correctly prunes undefined values when converting an array to an object', function (st) {
+        st.deepEqual(qs.parse('a[2]=b&a[99999999]=c'), { a: { 2: 'b', 99999999: 'c' } });
+        st.end();
+    });
+
+    t.test('supports malformed uri characters', function (st) {
+        st.deepEqual(qs.parse('{%:%}', { strictNullHandling: true }), { '{%:%}': null });
+        st.deepEqual(qs.parse('{%:%}='), { '{%:%}': '' });
+        st.deepEqual(qs.parse('foo=%:%}'), { foo: '%:%}' });
+        st.end();
+    });
+
+    t.test('doesn\'t produce empty keys', function (st) {
+        st.deepEqual(qs.parse('_r=1&'), { _r: '1' });
+        st.end();
+    });
+
+    t.test('cannot access Object prototype', function (st) {
+        qs.parse('constructor[prototype][bad]=bad');
+        qs.parse('bad[constructor][prototype][bad]=bad');
+        st.equal(typeof Object.prototype.bad, 'undefined');
+        st.end();
+    });
+
+    t.test('parses arrays of objects', function (st) {
+        st.deepEqual(qs.parse('a[][b]=c'), { a: [{ b: 'c' }] });
+        st.deepEqual(qs.parse('a[0][b]=c'), { a: [{ b: 'c' }] });
+        st.end();
+    });
+
+    t.test('allows for empty strings in arrays', function (st) {
+        st.deepEqual(qs.parse('a[]=b&a[]=&a[]=c'), { a: ['b', '', 'c'] });
+
+        st.deepEqual(
+            qs.parse('a[0]=b&a[1]&a[2]=c&a[19]=', { strictNullHandling: true, arrayLimit: 20 }),
+            { a: ['b', null, 'c', ''] },
+            'with arrayLimit 20 + array indices: null then empty string works'
+        );
+        st.deepEqual(
+            qs.parse('a[]=b&a[]&a[]=c&a[]=', { strictNullHandling: true, arrayLimit: 0 }),
+            { a: { 0: 'b', 1: null, 2: 'c', 3: '' } },
+            'with arrayLimit 0 + array brackets: null then empty string works'
+        );
+
+        st.deepEqual(
+            qs.parse('a[0]=b&a[1]=&a[2]=c&a[19]', { strictNullHandling: true, arrayLimit: 20 }),
+            { a: ['b', '', 'c', null] },
+            'with arrayLimit 20 + array indices: empty string then null works'
+        );
+        st.deepEqual(
+            qs.parse('a[]=b&a[]=&a[]=c&a[]', { strictNullHandling: true, arrayLimit: 0 }),
+            { a: { 0: 'b', 1: '', 2: 'c', 3: null } },
+            'with arrayLimit 0 + array brackets: empty string then null works'
+        );
+
+        st.deepEqual(
+            qs.parse('a[]=&a[]=b&a[]=c'),
+            { a: ['', 'b', 'c'] },
+            'array brackets: empty strings work'
+        );
+        st.end();
+    });
+
+    t.test('compacts sparse arrays', function (st) {
+        st.deepEqual(qs.parse('a[10]=1&a[2]=2', { arrayLimit: 20 }), { a: ['2', '1'] });
+        st.deepEqual(qs.parse('a[1][b][2][c]=1', { arrayLimit: 20 }), { a: [{ b: [{ c: '1' }] }] });
+        st.deepEqual(qs.parse('a[1][2][3][c]=1', { arrayLimit: 20 }), { a: [[[{ c: '1' }]]] });
+        st.deepEqual(qs.parse('a[1][2][3][c][1]=1', { arrayLimit: 20 }), { a: [[[{ c: ['1'] }]]] });
+        st.end();
+    });
+
+    t.test('parses sparse arrays', function (st) {
+        /* eslint no-sparse-arrays: 0 */
+        st.deepEqual(qs.parse('a[4]=1&a[1]=2', { allowSparse: true }), { a: [, '2', , , '1'] });
+        st.deepEqual(qs.parse('a[1][b][2][c]=1', { allowSparse: true }), { a: [, { b: [, , { c: '1' }] }] });
+        st.deepEqual(qs.parse('a[1][2][3][c]=1', { allowSparse: true }), { a: [, [, , [, , , { c: '1' }]]] });
+        st.deepEqual(qs.parse('a[1][2][3][c][1]=1', { allowSparse: true }), { a: [, [, , [, , , { c: [, '1'] }]]] });
+        st.end();
+    });
+
+    t.test('parses semi-parsed strings', function (st) {
+        st.deepEqual(qs.parse({ 'a[b]': 'c' }), { a: { b: 'c' } });
+        st.deepEqual(qs.parse({ 'a[b]': 'c', 'a[d]': 'e' }), { a: { b: 'c', d: 'e' } });
+        st.end();
+    });
+
+    t.test('parses buffers correctly', function (st) {
+        var b = SaferBuffer.from('test');
+        st.deepEqual(qs.parse({ a: b }), { a: b });
+        st.end();
+    });
+
+    t.test('parses jquery-param strings', function (st) {
+        // readable = 'filter[0][]=int1&filter[0][]==&filter[0][]=77&filter[]=and&filter[2][]=int2&filter[2][]==&filter[2][]=8'
+        var encoded = 'filter%5B0%5D%5B%5D=int1&filter%5B0%5D%5B%5D=%3D&filter%5B0%5D%5B%5D=77&filter%5B%5D=and&filter%5B2%5D%5B%5D=int2&filter%5B2%5D%5B%5D=%3D&filter%5B2%5D%5B%5D=8';
+        var expected = { filter: [['int1', '=', '77'], 'and', ['int2', '=', '8']] };
+        st.deepEqual(qs.parse(encoded), expected);
+        st.end();
+    });
+
+    t.test('continues parsing when no parent is found', function (st) {
+        st.deepEqual(qs.parse('[]=&a=b'), { 0: '', a: 'b' });
+        st.deepEqual(qs.parse('[]&a=b', { strictNullHandling: true }), { 0: null, a: 'b' });
+        st.deepEqual(qs.parse('[foo]=bar'), { foo: 'bar' });
+        st.end();
+    });
+
+    t.test('does not error when parsing a very long array', function (st) {
+        var str = 'a[]=a';
+        while (Buffer.byteLength(str) < 128 * 1024) {
+            str = str + '&' + str;
+        }
+
+        st.doesNotThrow(function () {
+            qs.parse(str);
+        });
+
+        st.end();
+    });
+
+    t.test('does not throw when a native prototype has an enumerable property', function (st) {
+        st.intercept(Object.prototype, 'crash', { value: '' });
+        st.intercept(Array.prototype, 'crash', { value: '' });
+
+        st.doesNotThrow(qs.parse.bind(null, 'a=b'));
+        st.deepEqual(qs.parse('a=b'), { a: 'b' });
+        st.doesNotThrow(qs.parse.bind(null, 'a[][b]=c'));
+        st.deepEqual(qs.parse('a[][b]=c'), { a: [{ b: 'c' }] });
+
+        st.end();
+    });
+
+    t.test('parses a string with an alternative string delimiter', function (st) {
+        st.deepEqual(qs.parse('a=b;c=d', { delimiter: ';' }), { a: 'b', c: 'd' });
+        st.end();
+    });
+
+    t.test('parses a string with an alternative RegExp delimiter', function (st) {
+        st.deepEqual(qs.parse('a=b; c=d', { delimiter: /[;,] */ }), { a: 'b', c: 'd' });
+        st.end();
+    });
+
+    t.test('does not use non-splittable objects as delimiters', function (st) {
+        st.deepEqual(qs.parse('a=b&c=d', { delimiter: true }), { a: 'b', c: 'd' });
+        st.end();
+    });
+
+    t.test('allows overriding parameter limit', function (st) {
+        st.deepEqual(qs.parse('a=b&c=d', { parameterLimit: 1 }), { a: 'b' });
+        st.end();
+    });
+
+    t.test('allows setting the parameter limit to Infinity', function (st) {
+        st.deepEqual(qs.parse('a=b&c=d', { parameterLimit: Infinity }), { a: 'b', c: 'd' });
+        st.end();
+    });
+
+    t.test('allows overriding array limit', function (st) {
+        st.deepEqual(qs.parse('a[0]=b', { arrayLimit: -1 }), { a: { 0: 'b' } });
+        st.deepEqual(qs.parse('a[0]=b', { arrayLimit: 0 }), { a: ['b'] });
+
+        st.deepEqual(qs.parse('a[-1]=b', { arrayLimit: -1 }), { a: { '-1': 'b' } });
+        st.deepEqual(qs.parse('a[-1]=b', { arrayLimit: 0 }), { a: { '-1': 'b' } });
+
+        st.deepEqual(qs.parse('a[0]=b&a[1]=c', { arrayLimit: -1 }), { a: { 0: 'b', 1: 'c' } });
+        st.deepEqual(qs.parse('a[0]=b&a[1]=c', { arrayLimit: 0 }), { a: { 0: 'b', 1: 'c' } });
+
+        st.end();
+    });
+
+    t.test('allows disabling array parsing', function (st) {
+        var indices = qs.parse('a[0]=b&a[1]=c', { parseArrays: false });
+        st.deepEqual(indices, { a: { 0: 'b', 1: 'c' } });
+        st.equal(Array.isArray(indices.a), false, 'parseArrays:false, indices case is not an array');
+
+        var emptyBrackets = qs.parse('a[]=b', { parseArrays: false });
+        st.deepEqual(emptyBrackets, { a: { 0: 'b' } });
+        st.equal(Array.isArray(emptyBrackets.a), false, 'parseArrays:false, empty brackets case is not an array');
+
+        st.end();
+    });
+
+    t.test('allows for query string prefix', function (st) {
+        st.deepEqual(qs.parse('?foo=bar', { ignoreQueryPrefix: true }), { foo: 'bar' });
+        st.deepEqual(qs.parse('foo=bar', { ignoreQueryPrefix: true }), { foo: 'bar' });
+        st.deepEqual(qs.parse('?foo=bar', { ignoreQueryPrefix: false }), { '?foo': 'bar' });
+
+        st.end();
+    });
+
+    t.test('parses an object', function (st) {
+        var input = {
+            'user[name]': { 'pop[bob]': 3 },
+            'user[email]': null
+        };
+
+        var expected = {
+            user: {
+                name: { 'pop[bob]': 3 },
+                email: null
+            }
+        };
+
+        var result = qs.parse(input);
+
+        st.deepEqual(result, expected);
+        st.end();
+    });
+
+    t.test('parses string with comma as array divider', function (st) {
+        st.deepEqual(qs.parse('foo=bar,tee', { comma: true }), { foo: ['bar', 'tee'] });
+        st.deepEqual(qs.parse('foo[bar]=coffee,tee', { comma: true }), { foo: { bar: ['coffee', 'tee'] } });
+        st.deepEqual(qs.parse('foo=', { comma: true }), { foo: '' });
+        st.deepEqual(qs.parse('foo', { comma: true }), { foo: '' });
+        st.deepEqual(qs.parse('foo', { comma: true, strictNullHandling: true }), { foo: null });
+
+        // test cases inversed from from stringify tests
+        st.deepEqual(qs.parse('a[0]=c'), { a: ['c'] });
+        st.deepEqual(qs.parse('a[]=c'), { a: ['c'] });
+        st.deepEqual(qs.parse('a[]=c', { comma: true }), { a: ['c'] });
+
+        st.deepEqual(qs.parse('a[0]=c&a[1]=d'), { a: ['c', 'd'] });
+        st.deepEqual(qs.parse('a[]=c&a[]=d'), { a: ['c', 'd'] });
+        st.deepEqual(qs.parse('a=c,d', { comma: true }), { a: ['c', 'd'] });
+
+        st.end();
+    });
+
+    t.test('parses values with comma as array divider', function (st) {
+        st.deepEqual(qs.parse({ foo: 'bar,tee' }, { comma: false }), { foo: 'bar,tee' });
+        st.deepEqual(qs.parse({ foo: 'bar,tee' }, { comma: true }), { foo: ['bar', 'tee'] });
+        st.end();
+    });
+
+    t.test('use number decoder, parses string that has one number with comma option enabled', function (st) {
+        var decoder = function (str, defaultDecoder, charset, type) {
+            if (!isNaN(Number(str))) {
+                return parseFloat(str);
+            }
+            return defaultDecoder(str, defaultDecoder, charset, type);
+        };
+
+        st.deepEqual(qs.parse('foo=1', { comma: true, decoder: decoder }), { foo: 1 });
+        st.deepEqual(qs.parse('foo=0', { comma: true, decoder: decoder }), { foo: 0 });
+
+        st.end();
+    });
+
+    t.test('parses brackets holds array of arrays when having two parts of strings with comma as array divider', function (st) {
+        st.deepEqual(qs.parse('foo[]=1,2,3&foo[]=4,5,6', { comma: true }), { foo: [['1', '2', '3'], ['4', '5', '6']] });
+        st.deepEqual(qs.parse('foo[]=1,2,3&foo[]=', { comma: true }), { foo: [['1', '2', '3'], ''] });
+        st.deepEqual(qs.parse('foo[]=1,2,3&foo[]=,', { comma: true }), { foo: [['1', '2', '3'], ['', '']] });
+        st.deepEqual(qs.parse('foo[]=1,2,3&foo[]=a', { comma: true }), { foo: [['1', '2', '3'], 'a'] });
+
+        st.end();
+    });
+
+    t.test('parses url-encoded brackets holds array of arrays when having two parts of strings with comma as array divider', function (st) {
+        st.deepEqual(qs.parse('foo%5B%5D=1,2,3&foo%5B%5D=4,5,6', { comma: true }), { foo: [['1', '2', '3'], ['4', '5', '6']] });
+        st.deepEqual(qs.parse('foo%5B%5D=1,2,3&foo%5B%5D=', { comma: true }), { foo: [['1', '2', '3'], ''] });
+        st.deepEqual(qs.parse('foo%5B%5D=1,2,3&foo%5B%5D=,', { comma: true }), { foo: [['1', '2', '3'], ['', '']] });
+        st.deepEqual(qs.parse('foo%5B%5D=1,2,3&foo%5B%5D=a', { comma: true }), { foo: [['1', '2', '3'], 'a'] });
+
+        st.end();
+    });
+
+    t.test('parses comma delimited array while having percent-encoded comma treated as normal text', function (st) {
+        st.deepEqual(qs.parse('foo=a%2Cb', { comma: true }), { foo: 'a,b' });
+        st.deepEqual(qs.parse('foo=a%2C%20b,d', { comma: true }), { foo: ['a, b', 'd'] });
+        st.deepEqual(qs.parse('foo=a%2C%20b,c%2C%20d', { comma: true }), { foo: ['a, b', 'c, d'] });
+
+        st.end();
+    });
+
+    t.test('parses an object in dot notation', function (st) {
+        var input = {
+            'user.name': { 'pop[bob]': 3 },
+            'user.email.': null
+        };
+
+        var expected = {
+            user: {
+                name: { 'pop[bob]': 3 },
+                email: null
+            }
+        };
+
+        var result = qs.parse(input, { allowDots: true });
+
+        st.deepEqual(result, expected);
+        st.end();
+    });
+
+    t.test('parses an object and not child values', function (st) {
+        var input = {
+            'user[name]': { 'pop[bob]': { test: 3 } },
+            'user[email]': null
+        };
+
+        var expected = {
+            user: {
+                name: { 'pop[bob]': { test: 3 } },
+                email: null
+            }
+        };
+
+        var result = qs.parse(input);
+
+        st.deepEqual(result, expected);
+        st.end();
+    });
+
+    t.test('does not blow up when Buffer global is missing', function (st) {
+        var restore = mockProperty(global, 'Buffer', { 'delete': true });
+
+        var result = qs.parse('a=b&c=d');
+
+        restore();
+
+        st.deepEqual(result, { a: 'b', c: 'd' });
+        st.end();
+    });
+
+    t.test('does not crash when parsing circular references', function (st) {
+        var a = {};
+        a.b = a;
+
+        var parsed;
+
+        st.doesNotThrow(function () {
+            parsed = qs.parse({ 'foo[bar]': 'baz', 'foo[baz]': a });
+        });
+
+        st.equal('foo' in parsed, true, 'parsed has "foo" property');
+        st.equal('bar' in parsed.foo, true);
+        st.equal('baz' in parsed.foo, true);
+        st.equal(parsed.foo.bar, 'baz');
+        st.deepEqual(parsed.foo.baz, a);
+        st.end();
+    });
+
+    t.test('does not crash when parsing deep objects', function (st) {
+        var parsed;
+        var str = 'foo';
+
+        for (var i = 0; i < 5000; i++) {
+            str += '[p]';
+        }
+
+        str += '=bar';
+
+        st.doesNotThrow(function () {
+            parsed = qs.parse(str, { depth: 5000 });
+        });
+
+        st.equal('foo' in parsed, true, 'parsed has "foo" property');
+
+        var depth = 0;
+        var ref = parsed.foo;
+        while ((ref = ref.p)) {
+            depth += 1;
+        }
+
+        st.equal(depth, 5000, 'parsed is 5000 properties deep');
+
+        st.end();
+    });
+
+    t.test('parses null objects correctly', { skip: !hasProto }, function (st) {
+        var a = { __proto__: null, b: 'c' };
+
+        st.deepEqual(qs.parse(a), { b: 'c' });
+        var result = qs.parse({ a: a });
+        st.equal('a' in result, true, 'result has "a" property');
+        st.deepEqual(result.a, a);
+        st.end();
+    });
+
+    t.test('parses dates correctly', function (st) {
+        var now = new Date();
+        st.deepEqual(qs.parse({ a: now }), { a: now });
+        st.end();
+    });
+
+    t.test('parses regular expressions correctly', function (st) {
+        var re = /^test$/;
+        st.deepEqual(qs.parse({ a: re }), { a: re });
+        st.end();
+    });
+
+    t.test('does not allow overwriting prototype properties', function (st) {
+        st.deepEqual(qs.parse('a[hasOwnProperty]=b', { allowPrototypes: false }), {});
+        st.deepEqual(qs.parse('hasOwnProperty=b', { allowPrototypes: false }), {});
+
+        st.deepEqual(
+            qs.parse('toString', { allowPrototypes: false }),
+            {},
+            'bare "toString" results in {}'
+        );
+
+        st.end();
+    });
+
+    t.test('can allow overwriting prototype properties', function (st) {
+        st.deepEqual(qs.parse('a[hasOwnProperty]=b', { allowPrototypes: true }), { a: { hasOwnProperty: 'b' } });
+        st.deepEqual(qs.parse('hasOwnProperty=b', { allowPrototypes: true }), { hasOwnProperty: 'b' });
+
+        st.deepEqual(
+            qs.parse('toString', { allowPrototypes: true }),
+            { toString: '' },
+            'bare "toString" results in { toString: "" }'
+        );
+
+        st.end();
+    });
+
+    t.test('does not crash when the global Object prototype is frozen', { skip: !hasPropertyDescriptors || !hasOverrideMistake }, function (st) {
+        // We can't actually freeze the global Object prototype as that will interfere with other tests, and once an object is frozen, it
+        // can't be unfrozen. Instead, we add a new non-writable property to simulate this.
+        st.teardown(mockProperty(Object.prototype, 'frozenProp', { value: 'foo', nonWritable: true, nonEnumerable: true }));
+
+        st['throws'](
+            function () {
+                var obj = {};
+                obj.frozenProp = 'bar';
+            },
+            // node < 6 has a different error message
+            /^TypeError: Cannot assign to read only property 'frozenProp' of (?:object '#<Object>'|#<Object>)/,
+            'regular assignment of an inherited non-writable property throws'
+        );
+
+        var parsed;
+        st.doesNotThrow(
+            function () {
+                parsed = qs.parse('frozenProp', { allowPrototypes: false });
+            },
+            'parsing a nonwritable Object.prototype property does not throw'
+        );
+
+        st.deepEqual(parsed, {}, 'bare "frozenProp" results in {}');
+
+        st.end();
+    });
+
+    t.test('params starting with a closing bracket', function (st) {
+        st.deepEqual(qs.parse(']=toString'), { ']': 'toString' });
+        st.deepEqual(qs.parse(']]=toString'), { ']]': 'toString' });
+        st.deepEqual(qs.parse(']hello]=toString'), { ']hello]': 'toString' });
+        st.end();
+    });
+
+    t.test('params starting with a starting bracket', function (st) {
+        st.deepEqual(qs.parse('[=toString'), { '[': 'toString' });
+        st.deepEqual(qs.parse('[[=toString'), { '[[': 'toString' });
+        st.deepEqual(qs.parse('[hello[=toString'), { '[hello[': 'toString' });
+        st.end();
+    });
+
+    t.test('add keys to objects', function (st) {
+        st.deepEqual(
+            qs.parse('a[b]=c&a=d'),
+            { a: { b: 'c', d: true } },
+            'can add keys to objects'
+        );
+
+        st.deepEqual(
+            qs.parse('a[b]=c&a=toString'),
+            { a: { b: 'c' } },
+            'can not overwrite prototype'
+        );
+
+        st.deepEqual(
+            qs.parse('a[b]=c&a=toString', { allowPrototypes: true }),
+            { a: { b: 'c', toString: true } },
+            'can overwrite prototype with allowPrototypes true'
+        );
+
+        st.deepEqual(
+            qs.parse('a[b]=c&a=toString', { plainObjects: true }),
+            { __proto__: null, a: { __proto__: null, b: 'c', toString: true } },
+            'can overwrite prototype with plainObjects true'
+        );
+
+        st.end();
+    });
+
+    t.test('dunder proto is ignored', function (st) {
+        var payload = 'categories[__proto__]=login&categories[__proto__]&categories[length]=42';
+        var result = qs.parse(payload, { allowPrototypes: true });
+
+        st.deepEqual(
+            result,
+            {
+                categories: {
+                    length: '42'
+                }
+            },
+            'silent [[Prototype]] payload'
+        );
+
+        var plainResult = qs.parse(payload, { allowPrototypes: true, plainObjects: true });
+
+        st.deepEqual(
+            plainResult,
+            {
+                __proto__: null,
+                categories: {
+                    __proto__: null,
+                    length: '42'
+                }
+            },
+            'silent [[Prototype]] payload: plain objects'
+        );
+
+        var query = qs.parse('categories[__proto__]=cats&categories[__proto__]=dogs&categories[some][json]=toInject', { allowPrototypes: true });
+
+        st.notOk(Array.isArray(query.categories), 'is not an array');
+        st.notOk(query.categories instanceof Array, 'is not instanceof an array');
+        st.deepEqual(query.categories, { some: { json: 'toInject' } });
+        st.equal(JSON.stringify(query.categories), '{"some":{"json":"toInject"}}', 'stringifies as a non-array');
+
+        st.deepEqual(
+            qs.parse('foo[__proto__][hidden]=value&foo[bar]=stuffs', { allowPrototypes: true }),
+            {
+                foo: {
+                    bar: 'stuffs'
+                }
+            },
+            'hidden values'
+        );
+
+        st.deepEqual(
+            qs.parse('foo[__proto__][hidden]=value&foo[bar]=stuffs', { allowPrototypes: true, plainObjects: true }),
+            {
+                __proto__: null,
+                foo: {
+                    __proto__: null,
+                    bar: 'stuffs'
+                }
+            },
+            'hidden values: plain objects'
+        );
+
+        st.end();
+    });
+
+    t.test('can return null objects', { skip: !hasProto }, function (st) {
+        var expected = {
+            __proto__: null,
+            a: {
+                __proto__: null,
+                b: 'c',
+                hasOwnProperty: 'd'
+            }
+        };
+        st.deepEqual(qs.parse('a[b]=c&a[hasOwnProperty]=d', { plainObjects: true }), expected);
+        st.deepEqual(qs.parse(null, { plainObjects: true }), { __proto__: null });
+        var expectedArray = {
+            __proto__: null,
+            a: {
+                __proto__: null,
+                0: 'b',
+                c: 'd'
+            }
+        };
+        st.deepEqual(qs.parse('a[]=b&a[c]=d', { plainObjects: true }), expectedArray);
+        st.end();
+    });
+
+    t.test('can parse with custom encoding', function (st) {
+        st.deepEqual(qs.parse('%8c%a7=%91%e5%8d%e3%95%7b', {
+            decoder: function (str) {
+                var reg = /%([0-9A-F]{2})/ig;
+                var result = [];
+                var parts = reg.exec(str);
+                while (parts) {
+                    result.push(parseInt(parts[1], 16));
+                    parts = reg.exec(str);
+                }
+                return String(iconv.decode(SaferBuffer.from(result), 'shift_jis'));
+            }
+        }), { 県: '大阪府' });
+        st.end();
+    });
+
+    t.test('receives the default decoder as a second argument', function (st) {
+        st.plan(1);
+        qs.parse('a', {
+            decoder: function (str, defaultDecoder) {
+                st.equal(defaultDecoder, utils.decode);
+            }
+        });
+        st.end();
+    });
+
+    t.test('throws error with wrong decoder', function (st) {
+        st['throws'](function () {
+            qs.parse({}, { decoder: 'string' });
+        }, new TypeError('Decoder has to be a function.'));
+        st.end();
+    });
+
+    t.test('does not mutate the options argument', function (st) {
+        var options = {};
+        qs.parse('a[b]=true', options);
+        st.deepEqual(options, {});
+        st.end();
+    });
+
+    t.test('throws if an invalid charset is specified', function (st) {
+        st['throws'](function () {
+            qs.parse('a=b', { charset: 'foobar' });
+        }, new TypeError('The charset option must be either utf-8, iso-8859-1, or undefined'));
+        st.end();
+    });
+
+    t.test('parses an iso-8859-1 string if asked to', function (st) {
+        st.deepEqual(qs.parse('%A2=%BD', { charset: 'iso-8859-1' }), { '¢': '½' });
+        st.end();
+    });
+
+    var urlEncodedCheckmarkInUtf8 = '%E2%9C%93';
+    var urlEncodedOSlashInUtf8 = '%C3%B8';
+    var urlEncodedNumCheckmark = '%26%2310003%3B';
+    var urlEncodedNumSmiley = '%26%239786%3B';
+
+    t.test('prefers an utf-8 charset specified by the utf8 sentinel to a default charset of iso-8859-1', function (st) {
+        st.deepEqual(qs.parse('utf8=' + urlEncodedCheckmarkInUtf8 + '&' + urlEncodedOSlashInUtf8 + '=' + urlEncodedOSlashInUtf8, { charsetSentinel: true, charset: 'iso-8859-1' }), { ø: 'ø' });
+        st.end();
+    });
+
+    t.test('prefers an iso-8859-1 charset specified by the utf8 sentinel to a default charset of utf-8', function (st) {
+        st.deepEqual(qs.parse('utf8=' + urlEncodedNumCheckmark + '&' + urlEncodedOSlashInUtf8 + '=' + urlEncodedOSlashInUtf8, { charsetSentinel: true, charset: 'utf-8' }), { 'Ã¸': 'Ã¸' });
+        st.end();
+    });
+
+    t.test('does not require the utf8 sentinel to be defined before the parameters whose decoding it affects', function (st) {
+        st.deepEqual(qs.parse('a=' + urlEncodedOSlashInUtf8 + '&utf8=' + urlEncodedNumCheckmark, { charsetSentinel: true, charset: 'utf-8' }), { a: 'Ã¸' });
+        st.end();
+    });
+
+    t.test('ignores an utf8 sentinel with an unknown value', function (st) {
+        st.deepEqual(qs.parse('utf8=foo&' + urlEncodedOSlashInUtf8 + '=' + urlEncodedOSlashInUtf8, { charsetSentinel: true, charset: 'utf-8' }), { ø: 'ø' });
+        st.end();
+    });
+
+    t.test('uses the utf8 sentinel to switch to utf-8 when no default charset is given', function (st) {
+        st.deepEqual(qs.parse('utf8=' + urlEncodedCheckmarkInUtf8 + '&' + urlEncodedOSlashInUtf8 + '=' + urlEncodedOSlashInUtf8, { charsetSentinel: true }), { ø: 'ø' });
+        st.end();
+    });
+
+    t.test('uses the utf8 sentinel to switch to iso-8859-1 when no default charset is given', function (st) {
+        st.deepEqual(qs.parse('utf8=' + urlEncodedNumCheckmark + '&' + urlEncodedOSlashInUtf8 + '=' + urlEncodedOSlashInUtf8, { charsetSentinel: true }), { 'Ã¸': 'Ã¸' });
+        st.end();
+    });
+
+    t.test('interprets numeric entities in iso-8859-1 when `interpretNumericEntities`', function (st) {
+        st.deepEqual(qs.parse('foo=' + urlEncodedNumSmiley, { charset: 'iso-8859-1', interpretNumericEntities: true }), { foo: '☺' });
+        st.end();
+    });
+
+    t.test('handles a custom decoder returning `null`, in the `iso-8859-1` charset, when `interpretNumericEntities`', function (st) {
+        st.deepEqual(qs.parse('foo=&bar=' + urlEncodedNumSmiley, {
+            charset: 'iso-8859-1',
+            decoder: function (str, defaultDecoder, charset) {
+                return str ? defaultDecoder(str, defaultDecoder, charset) : null;
+            },
+            interpretNumericEntities: true
+        }), { foo: null, bar: '☺' });
+        st.end();
+    });
+
+    t.test('handles a custom decoder returning `null`, with a string key of `null`', function (st) {
+        st.deepEqual(
+            qs.parse('null=1&ToNull=2', {
+                decoder: function (str, defaultDecoder, charset) {
+                    return str === 'ToNull' ? null : defaultDecoder(str, defaultDecoder, charset);
+                }
+            }),
+            { 'null': '1' },
+            '"null" key is not overridden by `null` decoder result'
+        );
+
+        st.end();
+    });
+
+    t.test('does not interpret numeric entities in iso-8859-1 when `interpretNumericEntities` is absent', function (st) {
+        st.deepEqual(qs.parse('foo=' + urlEncodedNumSmiley, { charset: 'iso-8859-1' }), { foo: '☺' });
+        st.end();
+    });
+
+    t.test('does not interpret numeric entities when the charset is utf-8, even when `interpretNumericEntities`', function (st) {
+        st.deepEqual(qs.parse('foo=' + urlEncodedNumSmiley, { charset: 'utf-8', interpretNumericEntities: true }), { foo: '☺' });
+        st.end();
+    });
+
+    t.test('interpretNumericEntities with comma:true and iso charset does not crash', function (st) {
+        st.deepEqual(
+            qs.parse('b&a[]=1,' + urlEncodedNumSmiley, { comma: true, charset: 'iso-8859-1', interpretNumericEntities: true }),
+            { b: '', a: ['1,☺'] }
+        );
+
+        st.end();
+    });
+
+    t.test('does not interpret %uXXXX syntax in iso-8859-1 mode', function (st) {
+        st.deepEqual(qs.parse('%u263A=%u263A', { charset: 'iso-8859-1' }), { '%u263A': '%u263A' });
+        st.end();
+    });
+
+    t.test('allows for decoding keys and values differently', function (st) {
+        var decoder = function (str, defaultDecoder, charset, type) {
+            if (type === 'key') {
+                return defaultDecoder(str, defaultDecoder, charset, type).toLowerCase();
+            }
+            if (type === 'value') {
+                return defaultDecoder(str, defaultDecoder, charset, type).toUpperCase();
+            }
+            throw 'this should never happen! type: ' + type;
+        };
+
+        st.deepEqual(qs.parse('KeY=vAlUe', { decoder: decoder }), { key: 'VALUE' });
+        st.end();
+    });
+
+    t.test('parameter limit tests', function (st) {
+        st.test('does not throw error when within parameter limit', function (sst) {
+            var result = qs.parse('a=1&b=2&c=3', { parameterLimit: 5, throwOnLimitExceeded: true });
+            sst.deepEqual(result, { a: '1', b: '2', c: '3' }, 'parses without errors');
+            sst.end();
+        });
+
+        st.test('throws error when throwOnLimitExceeded is present but not boolean', function (sst) {
+            sst['throws'](
+                function () {
+                    qs.parse('a=1&b=2&c=3&d=4&e=5&f=6', { parameterLimit: 3, throwOnLimitExceeded: 'true' });
+                },
+                new TypeError('`throwOnLimitExceeded` option must be a boolean'),
+                'throws error when throwOnLimitExceeded is present and not boolean'
+            );
+            sst.end();
+        });
+
+        st.test('throws error when parameter limit exceeded', function (sst) {
+            sst['throws'](
+                function () {
+                    qs.parse('a=1&b=2&c=3&d=4&e=5&f=6', { parameterLimit: 3, throwOnLimitExceeded: true });
+                },
+                new RangeError('Parameter limit exceeded. Only 3 parameters allowed.'),
+                'throws error when parameter limit is exceeded'
+            );
+            sst.end();
+        });
+
+        st.test('silently truncates when throwOnLimitExceeded is not given', function (sst) {
+            var result = qs.parse('a=1&b=2&c=3&d=4&e=5', { parameterLimit: 3 });
+            sst.deepEqual(result, { a: '1', b: '2', c: '3' }, 'parses and truncates silently');
+            sst.end();
+        });
+
+        st.test('silently truncates when parameter limit exceeded without error', function (sst) {
+            var result = qs.parse('a=1&b=2&c=3&d=4&e=5', { parameterLimit: 3, throwOnLimitExceeded: false });
+            sst.deepEqual(result, { a: '1', b: '2', c: '3' }, 'parses and truncates silently');
+            sst.end();
+        });
+
+        st.test('allows unlimited parameters when parameterLimit set to Infinity', function (sst) {
+            var result = qs.parse('a=1&b=2&c=3&d=4&e=5&f=6', { parameterLimit: Infinity });
+            sst.deepEqual(result, { a: '1', b: '2', c: '3', d: '4', e: '5', f: '6' }, 'parses all parameters without truncation');
+            sst.end();
+        });
+
+        st.end();
+    });
+
+    t.test('array limit tests', function (st) {
+        st.test('does not throw error when array is within limit', function (sst) {
+            var result = qs.parse('a[]=1&a[]=2&a[]=3', { arrayLimit: 5, throwOnLimitExceeded: true });
+            sst.deepEqual(result, { a: ['1', '2', '3'] }, 'parses array without errors');
+            sst.end();
+        });
+
+        st.test('throws error when throwOnLimitExceeded is present but not boolean for array limit', function (sst) {
+            sst['throws'](
+                function () {
+                    qs.parse('a[]=1&a[]=2&a[]=3&a[]=4', { arrayLimit: 3, throwOnLimitExceeded: 'true' });
+                },
+                new TypeError('`throwOnLimitExceeded` option must be a boolean'),
+                'throws error when throwOnLimitExceeded is present and not boolean for array limit'
+            );
+            sst.end();
+        });
+
+        st.test('throws error when array limit exceeded', function (sst) {
+            sst['throws'](
+                function () {
+                    qs.parse('a[]=1&a[]=2&a[]=3&a[]=4', { arrayLimit: 3, throwOnLimitExceeded: true });
+                },
+                new RangeError('Array limit exceeded. Only 3 elements allowed in an array.'),
+                'throws error when array limit is exceeded'
+            );
+            sst.end();
+        });
+
+        st.test('converts array to object if length is greater than limit', function (sst) {
+            var result = qs.parse('a[1]=1&a[2]=2&a[3]=3&a[4]=4&a[5]=5&a[6]=6', { arrayLimit: 5 });
+
+            sst.deepEqual(result, { a: { 1: '1', 2: '2', 3: '3', 4: '4', 5: '5', 6: '6' } }, 'parses into object if array length is greater than limit');
+            sst.end();
+        });
+
+        st.end();
+    });
+
+    t.end();
+});
+
+test('parses empty keys', function (t) {
+    emptyTestCases.forEach(function (testCase) {
+        t.test('skips empty string key with ' + testCase.input, function (st) {
+            st.deepEqual(qs.parse(testCase.input), testCase.noEmptyKeys);
+
+            st.end();
+        });
+    });
+});
+
+test('`duplicates` option', function (t) {
+    v.nonStrings.concat('not a valid option').forEach(function (invalidOption) {
+        if (typeof invalidOption !== 'undefined') {
+            t['throws'](
+                function () { qs.parse('', { duplicates: invalidOption }); },
+                TypeError,
+                'throws on invalid option: ' + inspect(invalidOption)
+            );
+        }
+    });
+
+    t.deepEqual(
+        qs.parse('foo=bar&foo=baz'),
+        { foo: ['bar', 'baz'] },
+        'duplicates: default, combine'
+    );
+
+    t.deepEqual(
+        qs.parse('foo=bar&foo=baz', { duplicates: 'combine' }),
+        { foo: ['bar', 'baz'] },
+        'duplicates: combine'
+    );
+
+    t.deepEqual(
+        qs.parse('foo=bar&foo=baz', { duplicates: 'first' }),
+        { foo: 'bar' },
+        'duplicates: first'
+    );
+
+    t.deepEqual(
+        qs.parse('foo=bar&foo=baz', { duplicates: 'last' }),
+        { foo: 'baz' },
+        'duplicates: last'
+    );
+
+    t.end();
+});
+
+test('qs strictDepth option - throw cases', function (t) {
+    t.test('throws an exception when depth exceeds the limit with strictDepth: true', function (st) {
+        st['throws'](
+            function () {
+                qs.parse('a[b][c][d][e][f][g][h][i]=j', { depth: 1, strictDepth: true });
+            },
+            RangeError,
+            'throws RangeError'
+        );
+        st.end();
+    });
+
+    t.test('throws an exception for multiple nested arrays with strictDepth: true', function (st) {
+        st['throws'](
+            function () {
+                qs.parse('a[0][1][2][3][4]=b', { depth: 3, strictDepth: true });
+            },
+            RangeError,
+            'throws RangeError'
+        );
+        st.end();
+    });
+
+    t.test('throws an exception for nested objects and arrays with strictDepth: true', function (st) {
+        st['throws'](
+            function () {
+                qs.parse('a[b][c][0][d][e]=f', { depth: 3, strictDepth: true });
+            },
+            RangeError,
+            'throws RangeError'
+        );
+        st.end();
+    });
+
+    t.test('throws an exception for different types of values with strictDepth: true', function (st) {
+        st['throws'](
+            function () {
+                qs.parse('a[b][c][d][e]=true&a[b][c][d][f]=42', { depth: 3, strictDepth: true });
+            },
+            RangeError,
+            'throws RangeError'
+        );
+        st.end();
+    });
+
+});
+
+test('qs strictDepth option - non-throw cases', function (t) {
+    t.test('when depth is 0 and strictDepth true, do not throw', function (st) {
+        st.doesNotThrow(
+            function () {
+                qs.parse('a[b][c][d][e]=true&a[b][c][d][f]=42', { depth: 0, strictDepth: true });
+            },
+            RangeError,
+            'does not throw RangeError'
+        );
+        st.end();
+    });
+
+    t.test('parses successfully when depth is within the limit with strictDepth: true', function (st) {
+        st.doesNotThrow(
+            function () {
+                var result = qs.parse('a[b]=c', { depth: 1, strictDepth: true });
+                st.deepEqual(result, { a: { b: 'c' } }, 'parses correctly');
+            }
+        );
+        st.end();
+    });
+
+    t.test('does not throw an exception when depth exceeds the limit with strictDepth: false', function (st) {
+        st.doesNotThrow(
+            function () {
+                var result = qs.parse('a[b][c][d][e][f][g][h][i]=j', { depth: 1 });
+                st.deepEqual(result, { a: { b: { '[c][d][e][f][g][h][i]': 'j' } } }, 'parses with depth limit');
+            }
+        );
+        st.end();
+    });
+
+    t.test('parses successfully when depth is within the limit with strictDepth: false', function (st) {
+        st.doesNotThrow(
+            function () {
+                var result = qs.parse('a[b]=c', { depth: 1 });
+                st.deepEqual(result, { a: { b: 'c' } }, 'parses correctly');
+            }
+        );
+        st.end();
+    });
+
+    t.test('does not throw when depth is exactly at the limit with strictDepth: true', function (st) {
+        st.doesNotThrow(
+            function () {
+                var result = qs.parse('a[b][c]=d', { depth: 2, strictDepth: true });
+                st.deepEqual(result, { a: { b: { c: 'd' } } }, 'parses correctly');
+            }
+        );
+        st.end();
+    });
+});
+
+test('DOS', function (t) {
+    var arr = [];
+    for (var i = 0; i < 105; i++) {
+        arr[arr.length] = 'x';
+    }
+    var attack = 'a[]=' + arr.join('&a[]=');
+    var result = qs.parse(attack, { arrayLimit: 100 });
+
+    t.notOk(Array.isArray(result.a), 'arrayLimit is respected: result is an object, not an array');
+    t.equal(Object.keys(result.a).length, 105, 'all values are preserved');
+
+    t.end();
+});
+
+test('arrayLimit boundary conditions', function (t) {
+    t.test('exactly at the limit stays as array', function (st) {
+        var result = qs.parse('a[]=1&a[]=2&a[]=3', { arrayLimit: 3 });
+        st.ok(Array.isArray(result.a), 'result is an array when exactly at limit');
+        st.deepEqual(result.a, ['1', '2', '3'], 'all values present');
+        st.end();
+    });
+
+    t.test('one over the limit converts to object', function (st) {
+        var result = qs.parse('a[]=1&a[]=2&a[]=3&a[]=4', { arrayLimit: 3 });
+        st.notOk(Array.isArray(result.a), 'result is not an array when over limit');
+        st.deepEqual(result.a, { 0: '1', 1: '2', 2: '3', 3: '4' }, 'all values preserved as object');
+        st.end();
+    });
+
+    t.test('arrayLimit 1 with two values', function (st) {
+        var result = qs.parse('a[]=1&a[]=2', { arrayLimit: 1 });
+        st.notOk(Array.isArray(result.a), 'result is not an array');
+        st.deepEqual(result.a, { 0: '1', 1: '2' }, 'both values preserved');
+        st.end();
+    });
+
+    t.end();
+});
+
+test('mixed array and object notation', function (t) {
+    t.test('array brackets with object key - under limit', function (st) {
+        st.deepEqual(
+            qs.parse('a[]=b&a[c]=d'),
+            { a: { 0: 'b', c: 'd' } },
+            'mixing [] and [key] converts to object'
+        );
+        st.end();
+    });
+
+    t.test('array index with object key - under limit', function (st) {
+        st.deepEqual(
+            qs.parse('a[0]=b&a[c]=d'),
+            { a: { 0: 'b', c: 'd' } },
+            'mixing [0] and [key] produces object'
+        );
+        st.end();
+    });
+
+    t.test('plain value with array brackets - under limit', function (st) {
+        st.deepEqual(
+            qs.parse('a=b&a[]=c', { arrayLimit: 20 }),
+            { a: ['b', 'c'] },
+            'plain value combined with [] stays as array under limit'
+        );
+        st.end();
+    });
+
+    t.test('array brackets with plain value - under limit', function (st) {
+        st.deepEqual(
+            qs.parse('a[]=b&a=c', { arrayLimit: 20 }),
+            { a: ['b', 'c'] },
+            '[] combined with plain value stays as array under limit'
+        );
+        st.end();
+    });
+
+    t.test('plain value with array index - under limit', function (st) {
+        st.deepEqual(
+            qs.parse('a=b&a[0]=c', { arrayLimit: 20 }),
+            { a: ['b', 'c'] },
+            'plain value combined with [0] stays as array under limit'
+        );
+        st.end();
+    });
+
+    t.test('multiple plain values with duplicates combine', function (st) {
+        st.deepEqual(
+            qs.parse('a=b&a=c&a=d', { arrayLimit: 20 }),
+            { a: ['b', 'c', 'd'] },
+            'duplicate plain keys combine into array'
+        );
+        st.end();
+    });
+
+    t.test('multiple plain values exceeding limit', function (st) {
+        st.deepEqual(
+            qs.parse('a=b&a=c&a=d', { arrayLimit: 2 }),
+            { a: { 0: 'b', 1: 'c', 2: 'd' } },
+            'duplicate plain keys convert to object when exceeding limit'
+        );
+        st.end();
+    });
+
+    t.end();
+});
diff --git a/server/node_modules/qs/test/stringify.js b/server/node_modules/qs/test/stringify.js
new file mode 100644
index 0000000..4d77694
--- /dev/null
+++ b/server/node_modules/qs/test/stringify.js
@@ -0,0 +1,1310 @@
+'use strict';
+
+var test = require('tape');
+var qs = require('../');
+var utils = require('../lib/utils');
+var iconv = require('iconv-lite');
+var SaferBuffer = require('safer-buffer').Buffer;
+var hasSymbols = require('has-symbols');
+var mockProperty = require('mock-property');
+var emptyTestCases = require('./empty-keys-cases').emptyTestCases;
+var hasProto = require('has-proto')();
+var hasBigInt = require('has-bigints')();
+
+test('stringify()', function (t) {
+    t.test('stringifies a querystring object', function (st) {
+        st.equal(qs.stringify({ a: 'b' }), 'a=b');
+        st.equal(qs.stringify({ a: 1 }), 'a=1');
+        st.equal(qs.stringify({ a: 1, b: 2 }), 'a=1&b=2');
+        st.equal(qs.stringify({ a: 'A_Z' }), 'a=A_Z');
+        st.equal(qs.stringify({ a: '€' }), 'a=%E2%82%AC');
+        st.equal(qs.stringify({ a: '' }), 'a=%EE%80%80');
+        st.equal(qs.stringify({ a: 'א' }), 'a=%D7%90');
+        st.equal(qs.stringify({ a: '𐐷' }), 'a=%F0%90%90%B7');
+        st.end();
+    });
+
+    t.test('stringifies falsy values', function (st) {
+        st.equal(qs.stringify(undefined), '');
+        st.equal(qs.stringify(null), '');
+        st.equal(qs.stringify(null, { strictNullHandling: true }), '');
+        st.equal(qs.stringify(false), '');
+        st.equal(qs.stringify(0), '');
+        st.end();
+    });
+
+    t.test('stringifies symbols', { skip: !hasSymbols() }, function (st) {
+        st.equal(qs.stringify(Symbol.iterator), '');
+        st.equal(qs.stringify([Symbol.iterator]), '0=Symbol%28Symbol.iterator%29');
+        st.equal(qs.stringify({ a: Symbol.iterator }), 'a=Symbol%28Symbol.iterator%29');
+        st.equal(
+            qs.stringify({ a: [Symbol.iterator] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }),
+            'a[]=Symbol%28Symbol.iterator%29'
+        );
+        st.end();
+    });
+
+    t.test('stringifies bigints', { skip: !hasBigInt }, function (st) {
+        var three = BigInt(3);
+        var encodeWithN = function (value, defaultEncoder, charset) {
+            var result = defaultEncoder(value, defaultEncoder, charset);
+            return typeof value === 'bigint' ? result + 'n' : result;
+        };
+        st.equal(qs.stringify(three), '');
+        st.equal(qs.stringify([three]), '0=3');
+        st.equal(qs.stringify([three], { encoder: encodeWithN }), '0=3n');
+        st.equal(qs.stringify({ a: three }), 'a=3');
+        st.equal(qs.stringify({ a: three }, { encoder: encodeWithN }), 'a=3n');
+        st.equal(
+            qs.stringify({ a: [three] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }),
+            'a[]=3'
+        );
+        st.equal(
+            qs.stringify({ a: [three] }, { encodeValuesOnly: true, encoder: encodeWithN, arrayFormat: 'brackets' }),
+            'a[]=3n'
+        );
+        st.end();
+    });
+
+    t.test('encodes dot in key of object when encodeDotInKeys and allowDots is provided', function (st) {
+        st.equal(
+            qs.stringify(
+                { 'name.obj': { first: 'John', last: 'Doe' } },
+                { allowDots: false, encodeDotInKeys: false }
+            ),
+            'name.obj%5Bfirst%5D=John&name.obj%5Blast%5D=Doe',
+            'with allowDots false and encodeDotInKeys false'
+        );
+        st.equal(
+            qs.stringify(
+                { 'name.obj': { first: 'John', last: 'Doe' } },
+                { allowDots: true, encodeDotInKeys: false }
+            ),
+            'name.obj.first=John&name.obj.last=Doe',
+            'with allowDots true and encodeDotInKeys false'
+        );
+        st.equal(
+            qs.stringify(
+                { 'name.obj': { first: 'John', last: 'Doe' } },
+                { allowDots: false, encodeDotInKeys: true }
+            ),
+            'name%252Eobj%5Bfirst%5D=John&name%252Eobj%5Blast%5D=Doe',
+            'with allowDots false and encodeDotInKeys true'
+        );
+        st.equal(
+            qs.stringify(
+                { 'name.obj': { first: 'John', last: 'Doe' } },
+                { allowDots: true, encodeDotInKeys: true }
+            ),
+            'name%252Eobj.first=John&name%252Eobj.last=Doe',
+            'with allowDots true and encodeDotInKeys true'
+        );
+
+        st.equal(
+            qs.stringify(
+                { 'name.obj.subobject': { 'first.godly.name': 'John', last: 'Doe' } },
+                { allowDots: false, encodeDotInKeys: false }
+            ),
+            'name.obj.subobject%5Bfirst.godly.name%5D=John&name.obj.subobject%5Blast%5D=Doe',
+            'with allowDots false and encodeDotInKeys false'
+        );
+        st.equal(
+            qs.stringify(
+                { 'name.obj.subobject': { 'first.godly.name': 'John', last: 'Doe' } },
+                { allowDots: true, encodeDotInKeys: false }
+            ),
+            'name.obj.subobject.first.godly.name=John&name.obj.subobject.last=Doe',
+            'with allowDots false and encodeDotInKeys false'
+        );
+        st.equal(
+            qs.stringify(
+                { 'name.obj.subobject': { 'first.godly.name': 'John', last: 'Doe' } },
+                { allowDots: false, encodeDotInKeys: true }
+            ),
+            'name%252Eobj%252Esubobject%5Bfirst.godly.name%5D=John&name%252Eobj%252Esubobject%5Blast%5D=Doe',
+            'with allowDots false and encodeDotInKeys true'
+        );
+        st.equal(
+            qs.stringify(
+                { 'name.obj.subobject': { 'first.godly.name': 'John', last: 'Doe' } },
+                { allowDots: true, encodeDotInKeys: true }
+            ),
+            'name%252Eobj%252Esubobject.first%252Egodly%252Ename=John&name%252Eobj%252Esubobject.last=Doe',
+            'with allowDots true and encodeDotInKeys true'
+        );
+
+        st.end();
+    });
+
+    t.test('should encode dot in key of object, and automatically set allowDots to `true` when encodeDotInKeys is true and allowDots in undefined', function (st) {
+        st.equal(
+            qs.stringify(
+                { 'name.obj.subobject': { 'first.godly.name': 'John', last: 'Doe' } },
+                { encodeDotInKeys: true }
+            ),
+            'name%252Eobj%252Esubobject.first%252Egodly%252Ename=John&name%252Eobj%252Esubobject.last=Doe',
+            'with allowDots undefined and encodeDotInKeys true'
+        );
+        st.end();
+    });
+
+    t.test('should encode dot in key of object when encodeDotInKeys and allowDots is provided, and nothing else when encodeValuesOnly is provided', function (st) {
+        st.equal(
+            qs.stringify({ 'name.obj': { first: 'John', last: 'Doe' } }, {
+                encodeDotInKeys: true, allowDots: true, encodeValuesOnly: true
+            }),
+            'name%2Eobj.first=John&name%2Eobj.last=Doe'
+        );
+
+        st.equal(
+            qs.stringify({ 'name.obj.subobject': { 'first.godly.name': 'John', last: 'Doe' } }, { allowDots: true, encodeDotInKeys: true, encodeValuesOnly: true }),
+            'name%2Eobj%2Esubobject.first%2Egodly%2Ename=John&name%2Eobj%2Esubobject.last=Doe'
+        );
+
+        st.end();
+    });
+
+    t.test('throws when `commaRoundTrip` is not a boolean', function (st) {
+        st['throws'](
+            function () { qs.stringify({}, { commaRoundTrip: 'not a boolean' }); },
+            TypeError,
+            'throws when `commaRoundTrip` is not a boolean'
+        );
+
+        st.end();
+    });
+
+    t.test('throws when `encodeDotInKeys` is not a boolean', function (st) {
+        st['throws'](
+            function () { qs.stringify({ a: [], b: 'zz' }, { encodeDotInKeys: 'foobar' }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.stringify({ a: [], b: 'zz' }, { encodeDotInKeys: 0 }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.stringify({ a: [], b: 'zz' }, { encodeDotInKeys: NaN }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.stringify({ a: [], b: 'zz' }, { encodeDotInKeys: null }); },
+            TypeError
+        );
+
+        st.end();
+    });
+
+    t.test('adds query prefix', function (st) {
+        st.equal(qs.stringify({ a: 'b' }, { addQueryPrefix: true }), '?a=b');
+        st.end();
+    });
+
+    t.test('with query prefix, outputs blank string given an empty object', function (st) {
+        st.equal(qs.stringify({}, { addQueryPrefix: true }), '');
+        st.end();
+    });
+
+    t.test('stringifies nested falsy values', function (st) {
+        st.equal(qs.stringify({ a: { b: { c: null } } }), 'a%5Bb%5D%5Bc%5D=');
+        st.equal(qs.stringify({ a: { b: { c: null } } }, { strictNullHandling: true }), 'a%5Bb%5D%5Bc%5D');
+        st.equal(qs.stringify({ a: { b: { c: false } } }), 'a%5Bb%5D%5Bc%5D=false');
+        st.end();
+    });
+
+    t.test('stringifies a nested object', function (st) {
+        st.equal(qs.stringify({ a: { b: 'c' } }), 'a%5Bb%5D=c');
+        st.equal(qs.stringify({ a: { b: { c: { d: 'e' } } } }), 'a%5Bb%5D%5Bc%5D%5Bd%5D=e');
+        st.end();
+    });
+
+    t.test('`allowDots` option: stringifies a nested object with dots notation', function (st) {
+        st.equal(qs.stringify({ a: { b: 'c' } }, { allowDots: true }), 'a.b=c');
+        st.equal(qs.stringify({ a: { b: { c: { d: 'e' } } } }, { allowDots: true }), 'a.b.c.d=e');
+        st.end();
+    });
+
+    t.test('stringifies an array value', function (st) {
+        st.equal(
+            qs.stringify({ a: ['b', 'c', 'd'] }, { arrayFormat: 'indices' }),
+            'a%5B0%5D=b&a%5B1%5D=c&a%5B2%5D=d',
+            'indices => indices'
+        );
+        st.equal(
+            qs.stringify({ a: ['b', 'c', 'd'] }, { arrayFormat: 'brackets' }),
+            'a%5B%5D=b&a%5B%5D=c&a%5B%5D=d',
+            'brackets => brackets'
+        );
+        st.equal(
+            qs.stringify({ a: ['b', 'c', 'd'] }, { arrayFormat: 'comma' }),
+            'a=b%2Cc%2Cd',
+            'comma => comma'
+        );
+        st.equal(
+            qs.stringify({ a: ['b', 'c', 'd'] }, { arrayFormat: 'comma', commaRoundTrip: true }),
+            'a=b%2Cc%2Cd',
+            'comma round trip => comma'
+        );
+        st.equal(
+            qs.stringify({ a: ['b', 'c', 'd'] }),
+            'a%5B0%5D=b&a%5B1%5D=c&a%5B2%5D=d',
+            'default => indices'
+        );
+        st.end();
+    });
+
+    t.test('`skipNulls` option', function (st) {
+        st.equal(
+            qs.stringify({ a: 'b', c: null }, { skipNulls: true }),
+            'a=b',
+            'omits nulls when asked'
+        );
+
+        st.equal(
+            qs.stringify({ a: { b: 'c', d: null } }, { skipNulls: true }),
+            'a%5Bb%5D=c',
+            'omits nested nulls when asked'
+        );
+
+        st.end();
+    });
+
+    t.test('omits array indices when asked', function (st) {
+        st.equal(qs.stringify({ a: ['b', 'c', 'd'] }, { indices: false }), 'a=b&a=c&a=d');
+
+        st.end();
+    });
+
+    t.test('omits object key/value pair when value is empty array', function (st) {
+        st.equal(qs.stringify({ a: [], b: 'zz' }), 'b=zz');
+
+        st.end();
+    });
+
+    t.test('should not omit object key/value pair when value is empty array and when asked', function (st) {
+        st.equal(qs.stringify({ a: [], b: 'zz' }), 'b=zz');
+        st.equal(qs.stringify({ a: [], b: 'zz' }, { allowEmptyArrays: false }), 'b=zz');
+        st.equal(qs.stringify({ a: [], b: 'zz' }, { allowEmptyArrays: true }), 'a[]&b=zz');
+
+        st.end();
+    });
+
+    t.test('should throw when allowEmptyArrays is not of type boolean', function (st) {
+        st['throws'](
+            function () { qs.stringify({ a: [], b: 'zz' }, { allowEmptyArrays: 'foobar' }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.stringify({ a: [], b: 'zz' }, { allowEmptyArrays: 0 }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.stringify({ a: [], b: 'zz' }, { allowEmptyArrays: NaN }); },
+            TypeError
+        );
+
+        st['throws'](
+            function () { qs.stringify({ a: [], b: 'zz' }, { allowEmptyArrays: null }); },
+            TypeError
+        );
+
+        st.end();
+    });
+
+    t.test('allowEmptyArrays + strictNullHandling', function (st) {
+        st.equal(
+            qs.stringify(
+                { testEmptyArray: [] },
+                { strictNullHandling: true, allowEmptyArrays: true }
+            ),
+            'testEmptyArray[]'
+        );
+
+        st.end();
+    });
+
+    t.test('stringifies an array value with one item vs multiple items', function (st) {
+        st.test('non-array item', function (s2t) {
+            s2t.equal(qs.stringify({ a: 'c' }, { encodeValuesOnly: true, arrayFormat: 'indices' }), 'a=c');
+            s2t.equal(qs.stringify({ a: 'c' }, { encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a=c');
+            s2t.equal(qs.stringify({ a: 'c' }, { encodeValuesOnly: true, arrayFormat: 'comma' }), 'a=c');
+            s2t.equal(qs.stringify({ a: 'c' }, { encodeValuesOnly: true }), 'a=c');
+
+            s2t.end();
+        });
+
+        st.test('array with a single item', function (s2t) {
+            s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true, arrayFormat: 'indices' }), 'a[0]=c');
+            s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a[]=c');
+            s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true, arrayFormat: 'comma' }), 'a=c');
+            s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true, arrayFormat: 'comma', commaRoundTrip: true }), 'a[]=c'); // so it parses back as an array
+            s2t.equal(qs.stringify({ a: ['c'] }, { encodeValuesOnly: true }), 'a[0]=c');
+
+            s2t.end();
+        });
+
+        st.test('array with multiple items', function (s2t) {
+            s2t.equal(qs.stringify({ a: ['c', 'd'] }, { encodeValuesOnly: true, arrayFormat: 'indices' }), 'a[0]=c&a[1]=d');
+            s2t.equal(qs.stringify({ a: ['c', 'd'] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a[]=c&a[]=d');
+            s2t.equal(qs.stringify({ a: ['c', 'd'] }, { encodeValuesOnly: true, arrayFormat: 'comma' }), 'a=c,d');
+            s2t.equal(qs.stringify({ a: ['c', 'd'] }, { encodeValuesOnly: true, arrayFormat: 'comma', commaRoundTrip: true }), 'a=c,d');
+            s2t.equal(qs.stringify({ a: ['c', 'd'] }, { encodeValuesOnly: true }), 'a[0]=c&a[1]=d');
+
+            s2t.end();
+        });
+
+        st.test('array with multiple items with a comma inside', function (s2t) {
+            s2t.equal(qs.stringify({ a: ['c,d', 'e'] }, { encodeValuesOnly: true, arrayFormat: 'comma' }), 'a=c%2Cd,e');
+            s2t.equal(qs.stringify({ a: ['c,d', 'e'] }, { arrayFormat: 'comma' }), 'a=c%2Cd%2Ce');
+
+            s2t.equal(qs.stringify({ a: ['c,d', 'e'] }, { encodeValuesOnly: true, arrayFormat: 'comma', commaRoundTrip: true }), 'a=c%2Cd,e');
+            s2t.equal(qs.stringify({ a: ['c,d', 'e'] }, { arrayFormat: 'comma', commaRoundTrip: true }), 'a=c%2Cd%2Ce');
+
+            s2t.end();
+        });
+
+        st.end();
+    });
+
+    t.test('stringifies a nested array value', function (st) {
+        st.equal(qs.stringify({ a: { b: ['c', 'd'] } }, { encodeValuesOnly: true, arrayFormat: 'indices' }), 'a[b][0]=c&a[b][1]=d');
+        st.equal(qs.stringify({ a: { b: ['c', 'd'] } }, { encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a[b][]=c&a[b][]=d');
+        st.equal(qs.stringify({ a: { b: ['c', 'd'] } }, { encodeValuesOnly: true, arrayFormat: 'comma' }), 'a[b]=c,d');
+        st.equal(qs.stringify({ a: { b: ['c', 'd'] } }, { encodeValuesOnly: true }), 'a[b][0]=c&a[b][1]=d');
+        st.end();
+    });
+
+    t.test('stringifies comma and empty array values', function (st) {
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: false, arrayFormat: 'indices' }), 'a[0]=,&a[1]=&a[2]=c,d%');
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: false, arrayFormat: 'brackets' }), 'a[]=,&a[]=&a[]=c,d%');
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: false, arrayFormat: 'comma' }), 'a=,,,c,d%');
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: false, arrayFormat: 'repeat' }), 'a=,&a=&a=c,d%');
+
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: true, encodeValuesOnly: true, arrayFormat: 'indices' }), 'a[0]=%2C&a[1]=&a[2]=c%2Cd%25');
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: true, encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a[]=%2C&a[]=&a[]=c%2Cd%25');
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: true, encodeValuesOnly: true, arrayFormat: 'comma' }), 'a=%2C,,c%2Cd%25');
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: true, encodeValuesOnly: true, arrayFormat: 'repeat' }), 'a=%2C&a=&a=c%2Cd%25');
+
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: true, encodeValuesOnly: false, arrayFormat: 'indices' }), 'a%5B0%5D=%2C&a%5B1%5D=&a%5B2%5D=c%2Cd%25');
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: true, encodeValuesOnly: false, arrayFormat: 'brackets' }), 'a%5B%5D=%2C&a%5B%5D=&a%5B%5D=c%2Cd%25');
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: true, encodeValuesOnly: false, arrayFormat: 'comma' }), 'a=%2C%2C%2Cc%2Cd%25');
+        st.equal(qs.stringify({ a: [',', '', 'c,d%'] }, { encode: true, encodeValuesOnly: false, arrayFormat: 'repeat' }), 'a=%2C&a=&a=c%2Cd%25');
+
+        st.end();
+    });
+
+    t.test('stringifies comma and empty non-array values', function (st) {
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: false, arrayFormat: 'indices' }), 'a=,&b=&c=c,d%');
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: false, arrayFormat: 'brackets' }), 'a=,&b=&c=c,d%');
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: false, arrayFormat: 'comma' }), 'a=,&b=&c=c,d%');
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: false, arrayFormat: 'repeat' }), 'a=,&b=&c=c,d%');
+
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: true, encodeValuesOnly: true, arrayFormat: 'indices' }), 'a=%2C&b=&c=c%2Cd%25');
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: true, encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a=%2C&b=&c=c%2Cd%25');
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: true, encodeValuesOnly: true, arrayFormat: 'comma' }), 'a=%2C&b=&c=c%2Cd%25');
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: true, encodeValuesOnly: true, arrayFormat: 'repeat' }), 'a=%2C&b=&c=c%2Cd%25');
+
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: true, encodeValuesOnly: false, arrayFormat: 'indices' }), 'a=%2C&b=&c=c%2Cd%25');
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: true, encodeValuesOnly: false, arrayFormat: 'brackets' }), 'a=%2C&b=&c=c%2Cd%25');
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: true, encodeValuesOnly: false, arrayFormat: 'comma' }), 'a=%2C&b=&c=c%2Cd%25');
+        st.equal(qs.stringify({ a: ',', b: '', c: 'c,d%' }, { encode: true, encodeValuesOnly: false, arrayFormat: 'repeat' }), 'a=%2C&b=&c=c%2Cd%25');
+
+        st.end();
+    });
+
+    t.test('stringifies a nested array value with dots notation', function (st) {
+        st.equal(
+            qs.stringify(
+                { a: { b: ['c', 'd'] } },
+                { allowDots: true, encodeValuesOnly: true, arrayFormat: 'indices' }
+            ),
+            'a.b[0]=c&a.b[1]=d',
+            'indices: stringifies with dots + indices'
+        );
+        st.equal(
+            qs.stringify(
+                { a: { b: ['c', 'd'] } },
+                { allowDots: true, encodeValuesOnly: true, arrayFormat: 'brackets' }
+            ),
+            'a.b[]=c&a.b[]=d',
+            'brackets: stringifies with dots + brackets'
+        );
+        st.equal(
+            qs.stringify(
+                { a: { b: ['c', 'd'] } },
+                { allowDots: true, encodeValuesOnly: true, arrayFormat: 'comma' }
+            ),
+            'a.b=c,d',
+            'comma: stringifies with dots + comma'
+        );
+        st.equal(
+            qs.stringify(
+                { a: { b: ['c', 'd'] } },
+                { allowDots: true, encodeValuesOnly: true }
+            ),
+            'a.b[0]=c&a.b[1]=d',
+            'default: stringifies with dots + indices'
+        );
+        st.end();
+    });
+
+    t.test('stringifies an object inside an array', function (st) {
+        st.equal(
+            qs.stringify({ a: [{ b: 'c' }] }, { arrayFormat: 'indices', encodeValuesOnly: true }),
+            'a[0][b]=c',
+            'indices => indices'
+        );
+        st.equal(
+            qs.stringify({ a: [{ b: 'c' }] }, { arrayFormat: 'repeat', encodeValuesOnly: true }),
+            'a[b]=c',
+            'repeat => repeat'
+        );
+        st.equal(
+            qs.stringify({ a: [{ b: 'c' }] }, { arrayFormat: 'brackets', encodeValuesOnly: true }),
+            'a[][b]=c',
+            'brackets => brackets'
+        );
+        st.equal(
+            qs.stringify({ a: [{ b: 'c' }] }, { encodeValuesOnly: true }),
+            'a[0][b]=c',
+            'default => indices'
+        );
+
+        st.equal(
+            qs.stringify({ a: [{ b: { c: [1] } }] }, { arrayFormat: 'indices', encodeValuesOnly: true }),
+            'a[0][b][c][0]=1',
+            'indices => indices'
+        );
+        st.equal(
+            qs.stringify({ a: [{ b: { c: [1] } }] }, { arrayFormat: 'repeat', encodeValuesOnly: true }),
+            'a[b][c]=1',
+            'repeat => repeat'
+        );
+        st.equal(
+            qs.stringify({ a: [{ b: { c: [1] } }] }, { arrayFormat: 'brackets', encodeValuesOnly: true }),
+            'a[][b][c][]=1',
+            'brackets => brackets'
+        );
+        st.equal(
+            qs.stringify({ a: [{ b: { c: [1] } }] }, { encodeValuesOnly: true }),
+            'a[0][b][c][0]=1',
+            'default => indices'
+        );
+
+        st.end();
+    });
+
+    t.test('stringifies an array with mixed objects and primitives', function (st) {
+        st.equal(
+            qs.stringify({ a: [{ b: 1 }, 2, 3] }, { encodeValuesOnly: true, arrayFormat: 'indices' }),
+            'a[0][b]=1&a[1]=2&a[2]=3',
+            'indices => indices'
+        );
+        st.equal(
+            qs.stringify({ a: [{ b: 1 }, 2, 3] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }),
+            'a[][b]=1&a[]=2&a[]=3',
+            'brackets => brackets'
+        );
+        st.equal(
+            qs.stringify({ a: [{ b: 1 }, 2, 3] }, { encodeValuesOnly: true, arrayFormat: 'comma' }),
+            '???',
+            'brackets => brackets',
+            { skip: 'TODO: figure out what this should do' }
+        );
+        st.equal(
+            qs.stringify({ a: [{ b: 1 }, 2, 3] }, { encodeValuesOnly: true }),
+            'a[0][b]=1&a[1]=2&a[2]=3',
+            'default => indices'
+        );
+
+        st.end();
+    });
+
+    t.test('stringifies an object inside an array with dots notation', function (st) {
+        st.equal(
+            qs.stringify(
+                { a: [{ b: 'c' }] },
+                { allowDots: true, encode: false, arrayFormat: 'indices' }
+            ),
+            'a[0].b=c',
+            'indices => indices'
+        );
+        st.equal(
+            qs.stringify(
+                { a: [{ b: 'c' }] },
+                { allowDots: true, encode: false, arrayFormat: 'brackets' }
+            ),
+            'a[].b=c',
+            'brackets => brackets'
+        );
+        st.equal(
+            qs.stringify(
+                { a: [{ b: 'c' }] },
+                { allowDots: true, encode: false }
+            ),
+            'a[0].b=c',
+            'default => indices'
+        );
+
+        st.equal(
+            qs.stringify(
+                { a: [{ b: { c: [1] } }] },
+                { allowDots: true, encode: false, arrayFormat: 'indices' }
+            ),
+            'a[0].b.c[0]=1',
+            'indices => indices'
+        );
+        st.equal(
+            qs.stringify(
+                { a: [{ b: { c: [1] } }] },
+                { allowDots: true, encode: false, arrayFormat: 'brackets' }
+            ),
+            'a[].b.c[]=1',
+            'brackets => brackets'
+        );
+        st.equal(
+            qs.stringify(
+                { a: [{ b: { c: [1] } }] },
+                { allowDots: true, encode: false }
+            ),
+            'a[0].b.c[0]=1',
+            'default => indices'
+        );
+
+        st.end();
+    });
+
+    t.test('does not omit object keys when indices = false', function (st) {
+        st.equal(qs.stringify({ a: [{ b: 'c' }] }, { indices: false }), 'a%5Bb%5D=c');
+        st.end();
+    });
+
+    t.test('uses indices notation for arrays when indices=true', function (st) {
+        st.equal(qs.stringify({ a: ['b', 'c'] }, { indices: true }), 'a%5B0%5D=b&a%5B1%5D=c');
+        st.end();
+    });
+
+    t.test('uses indices notation for arrays when no arrayFormat is specified', function (st) {
+        st.equal(qs.stringify({ a: ['b', 'c'] }), 'a%5B0%5D=b&a%5B1%5D=c');
+        st.end();
+    });
+
+    t.test('uses indices notation for arrays when arrayFormat=indices', function (st) {
+        st.equal(qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'indices' }), 'a%5B0%5D=b&a%5B1%5D=c');
+        st.end();
+    });
+
+    t.test('uses repeat notation for arrays when arrayFormat=repeat', function (st) {
+        st.equal(qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'repeat' }), 'a=b&a=c');
+        st.end();
+    });
+
+    t.test('uses brackets notation for arrays when arrayFormat=brackets', function (st) {
+        st.equal(qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'brackets' }), 'a%5B%5D=b&a%5B%5D=c');
+        st.end();
+    });
+
+    t.test('stringifies a complicated object', function (st) {
+        st.equal(qs.stringify({ a: { b: 'c', d: 'e' } }), 'a%5Bb%5D=c&a%5Bd%5D=e');
+        st.end();
+    });
+
+    t.test('stringifies an empty value', function (st) {
+        st.equal(qs.stringify({ a: '' }), 'a=');
+        st.equal(qs.stringify({ a: null }, { strictNullHandling: true }), 'a');
+
+        st.equal(qs.stringify({ a: '', b: '' }), 'a=&b=');
+        st.equal(qs.stringify({ a: null, b: '' }, { strictNullHandling: true }), 'a&b=');
+
+        st.equal(qs.stringify({ a: { b: '' } }), 'a%5Bb%5D=');
+        st.equal(qs.stringify({ a: { b: null } }, { strictNullHandling: true }), 'a%5Bb%5D');
+        st.equal(qs.stringify({ a: { b: null } }, { strictNullHandling: false }), 'a%5Bb%5D=');
+
+        st.end();
+    });
+
+    t.test('stringifies an empty array in different arrayFormat', function (st) {
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false }), 'b[0]=&c=c');
+        // arrayFormat default
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'indices' }), 'b[0]=&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'brackets' }), 'b[]=&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'repeat' }), 'b=&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma' }), 'b=&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma', commaRoundTrip: true }), 'b[]=&c=c');
+        // with strictNullHandling
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'indices', strictNullHandling: true }), 'b[0]&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'brackets', strictNullHandling: true }), 'b[]&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'repeat', strictNullHandling: true }), 'b&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma', strictNullHandling: true }), 'b&c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma', strictNullHandling: true, commaRoundTrip: true }), 'b[]&c=c');
+        // with skipNulls
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'indices', skipNulls: true }), 'c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'brackets', skipNulls: true }), 'c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'repeat', skipNulls: true }), 'c=c');
+        st.equal(qs.stringify({ a: [], b: [null], c: 'c' }, { encode: false, arrayFormat: 'comma', skipNulls: true }), 'c=c');
+
+        st.end();
+    });
+
+    t.test('stringifies a null object', { skip: !hasProto }, function (st) {
+        st.equal(qs.stringify({ __proto__: null, a: 'b' }), 'a=b');
+        st.end();
+    });
+
+    t.test('returns an empty string for invalid input', function (st) {
+        st.equal(qs.stringify(undefined), '');
+        st.equal(qs.stringify(false), '');
+        st.equal(qs.stringify(null), '');
+        st.equal(qs.stringify(''), '');
+        st.end();
+    });
+
+    t.test('stringifies an object with a null object as a child', { skip: !hasProto }, function (st) {
+        st.equal(qs.stringify({ a: { __proto__: null, b: 'c' } }), 'a%5Bb%5D=c');
+        st.end();
+    });
+
+    t.test('drops keys with a value of undefined', function (st) {
+        st.equal(qs.stringify({ a: undefined }), '');
+
+        st.equal(qs.stringify({ a: { b: undefined, c: null } }, { strictNullHandling: true }), 'a%5Bc%5D');
+        st.equal(qs.stringify({ a: { b: undefined, c: null } }, { strictNullHandling: false }), 'a%5Bc%5D=');
+        st.equal(qs.stringify({ a: { b: undefined, c: '' } }), 'a%5Bc%5D=');
+        st.end();
+    });
+
+    t.test('url encodes values', function (st) {
+        st.equal(qs.stringify({ a: 'b c' }), 'a=b%20c');
+        st.end();
+    });
+
+    t.test('stringifies a date', function (st) {
+        var now = new Date();
+        var str = 'a=' + encodeURIComponent(now.toISOString());
+        st.equal(qs.stringify({ a: now }), str);
+        st.end();
+    });
+
+    t.test('stringifies the weird object from qs', function (st) {
+        st.equal(qs.stringify({ 'my weird field': '~q1!2"\'w$5&7/z8)?' }), 'my%20weird%20field=~q1%212%22%27w%245%267%2Fz8%29%3F');
+        st.end();
+    });
+
+    t.test('skips properties that are part of the object prototype', function (st) {
+        st.intercept(Object.prototype, 'crash', { value: 'test' });
+
+        st.equal(qs.stringify({ a: 'b' }), 'a=b');
+        st.equal(qs.stringify({ a: { b: 'c' } }), 'a%5Bb%5D=c');
+
+        st.end();
+    });
+
+    t.test('stringifies boolean values', function (st) {
+        st.equal(qs.stringify({ a: true }), 'a=true');
+        st.equal(qs.stringify({ a: { b: true } }), 'a%5Bb%5D=true');
+        st.equal(qs.stringify({ b: false }), 'b=false');
+        st.equal(qs.stringify({ b: { c: false } }), 'b%5Bc%5D=false');
+        st.end();
+    });
+
+    t.test('stringifies buffer values', function (st) {
+        st.equal(qs.stringify({ a: SaferBuffer.from('test') }), 'a=test');
+        st.equal(qs.stringify({ a: { b: SaferBuffer.from('test') } }), 'a%5Bb%5D=test');
+        st.end();
+    });
+
+    t.test('stringifies an object using an alternative delimiter', function (st) {
+        st.equal(qs.stringify({ a: 'b', c: 'd' }, { delimiter: ';' }), 'a=b;c=d');
+        st.end();
+    });
+
+    t.test('does not blow up when Buffer global is missing', function (st) {
+        var restore = mockProperty(global, 'Buffer', { 'delete': true });
+
+        var result = qs.stringify({ a: 'b', c: 'd' });
+
+        restore();
+
+        st.equal(result, 'a=b&c=d');
+        st.end();
+    });
+
+    t.test('does not crash when parsing circular references', function (st) {
+        var a = {};
+        a.b = a;
+
+        st['throws'](
+            function () { qs.stringify({ 'foo[bar]': 'baz', 'foo[baz]': a }); },
+            /RangeError: Cyclic object value/,
+            'cyclic values throw'
+        );
+
+        var circular = {
+            a: 'value'
+        };
+        circular.a = circular;
+        st['throws'](
+            function () { qs.stringify(circular); },
+            /RangeError: Cyclic object value/,
+            'cyclic values throw'
+        );
+
+        var arr = ['a'];
+        st.doesNotThrow(
+            function () { qs.stringify({ x: arr, y: arr }); },
+            'non-cyclic values do not throw'
+        );
+
+        st.end();
+    });
+
+    t.test('non-circular duplicated references can still work', function (st) {
+        var hourOfDay = {
+            'function': 'hour_of_day'
+        };
+
+        var p1 = {
+            'function': 'gte',
+            arguments: [hourOfDay, 0]
+        };
+        var p2 = {
+            'function': 'lte',
+            arguments: [hourOfDay, 23]
+        };
+
+        st.equal(
+            qs.stringify({ filters: { $and: [p1, p2] } }, { encodeValuesOnly: true, arrayFormat: 'indices' }),
+            'filters[$and][0][function]=gte&filters[$and][0][arguments][0][function]=hour_of_day&filters[$and][0][arguments][1]=0&filters[$and][1][function]=lte&filters[$and][1][arguments][0][function]=hour_of_day&filters[$and][1][arguments][1]=23'
+        );
+        st.equal(
+            qs.stringify({ filters: { $and: [p1, p2] } }, { encodeValuesOnly: true, arrayFormat: 'brackets' }),
+            'filters[$and][][function]=gte&filters[$and][][arguments][][function]=hour_of_day&filters[$and][][arguments][]=0&filters[$and][][function]=lte&filters[$and][][arguments][][function]=hour_of_day&filters[$and][][arguments][]=23'
+        );
+        st.equal(
+            qs.stringify({ filters: { $and: [p1, p2] } }, { encodeValuesOnly: true, arrayFormat: 'repeat' }),
+            'filters[$and][function]=gte&filters[$and][arguments][function]=hour_of_day&filters[$and][arguments]=0&filters[$and][function]=lte&filters[$and][arguments][function]=hour_of_day&filters[$and][arguments]=23'
+        );
+
+        st.end();
+    });
+
+    t.test('selects properties when filter=array', function (st) {
+        st.equal(qs.stringify({ a: 'b' }, { filter: ['a'] }), 'a=b');
+        st.equal(qs.stringify({ a: 1 }, { filter: [] }), '');
+
+        st.equal(
+            qs.stringify(
+                { a: { b: [1, 2, 3, 4], c: 'd' }, c: 'f' },
+                { filter: ['a', 'b', 0, 2], arrayFormat: 'indices' }
+            ),
+            'a%5Bb%5D%5B0%5D=1&a%5Bb%5D%5B2%5D=3',
+            'indices => indices'
+        );
+        st.equal(
+            qs.stringify(
+                { a: { b: [1, 2, 3, 4], c: 'd' }, c: 'f' },
+                { filter: ['a', 'b', 0, 2], arrayFormat: 'brackets' }
+            ),
+            'a%5Bb%5D%5B%5D=1&a%5Bb%5D%5B%5D=3',
+            'brackets => brackets'
+        );
+        st.equal(
+            qs.stringify(
+                { a: { b: [1, 2, 3, 4], c: 'd' }, c: 'f' },
+                { filter: ['a', 'b', 0, 2] }
+            ),
+            'a%5Bb%5D%5B0%5D=1&a%5Bb%5D%5B2%5D=3',
+            'default => indices'
+        );
+
+        st.end();
+    });
+
+    t.test('supports custom representations when filter=function', function (st) {
+        var calls = 0;
+        var obj = { a: 'b', c: 'd', e: { f: new Date(1257894000000) } };
+        var filterFunc = function (prefix, value) {
+            calls += 1;
+            if (calls === 1) {
+                st.equal(prefix, '', 'prefix is empty');
+                st.equal(value, obj);
+            } else if (prefix === 'c') {
+                return void 0;
+            } else if (value instanceof Date) {
+                st.equal(prefix, 'e[f]');
+                return value.getTime();
+            }
+            return value;
+        };
+
+        st.equal(qs.stringify(obj, { filter: filterFunc }), 'a=b&e%5Bf%5D=1257894000000');
+        st.equal(calls, 5);
+        st.end();
+    });
+
+    t.test('can disable uri encoding', function (st) {
+        st.equal(qs.stringify({ a: 'b' }, { encode: false }), 'a=b');
+        st.equal(qs.stringify({ a: { b: 'c' } }, { encode: false }), 'a[b]=c');
+        st.equal(qs.stringify({ a: 'b', c: null }, { strictNullHandling: true, encode: false }), 'a=b&c');
+        st.end();
+    });
+
+    t.test('can sort the keys', function (st) {
+        var sort = function (a, b) {
+            return a.localeCompare(b);
+        };
+        st.equal(qs.stringify({ a: 'c', z: 'y', b: 'f' }, { sort: sort }), 'a=c&b=f&z=y');
+        st.equal(qs.stringify({ a: 'c', z: { j: 'a', i: 'b' }, b: 'f' }, { sort: sort }), 'a=c&b=f&z%5Bi%5D=b&z%5Bj%5D=a');
+        st.end();
+    });
+
+    t.test('can sort the keys at depth 3 or more too', function (st) {
+        var sort = function (a, b) {
+            return a.localeCompare(b);
+        };
+        st.equal(
+            qs.stringify(
+                { a: 'a', z: { zj: { zjb: 'zjb', zja: 'zja' }, zi: { zib: 'zib', zia: 'zia' } }, b: 'b' },
+                { sort: sort, encode: false }
+            ),
+            'a=a&b=b&z[zi][zia]=zia&z[zi][zib]=zib&z[zj][zja]=zja&z[zj][zjb]=zjb'
+        );
+        st.equal(
+            qs.stringify(
+                { a: 'a', z: { zj: { zjb: 'zjb', zja: 'zja' }, zi: { zib: 'zib', zia: 'zia' } }, b: 'b' },
+                { sort: null, encode: false }
+            ),
+            'a=a&z[zj][zjb]=zjb&z[zj][zja]=zja&z[zi][zib]=zib&z[zi][zia]=zia&b=b'
+        );
+        st.end();
+    });
+
+    t.test('can stringify with custom encoding', function (st) {
+        st.equal(qs.stringify({ 県: '大阪府', '': '' }, {
+            encoder: function (str) {
+                if (str.length === 0) {
+                    return '';
+                }
+                var buf = iconv.encode(str, 'shiftjis');
+                var result = [];
+                for (var i = 0; i < buf.length; ++i) {
+                    result.push(buf.readUInt8(i).toString(16));
+                }
+                return '%' + result.join('%');
+            }
+        }), '%8c%a7=%91%e5%8d%e3%95%7b&=');
+        st.end();
+    });
+
+    t.test('receives the default encoder as a second argument', function (st) {
+        st.plan(8);
+
+        qs.stringify({ a: 1, b: new Date(), c: true, d: [1] }, {
+            encoder: function (str) {
+                st.match(typeof str, /^(?:string|number|boolean)$/);
+                return '';
+            }
+        });
+
+        st.end();
+    });
+
+    t.test('receives the default encoder as a second argument', function (st) {
+        st.plan(2);
+
+        qs.stringify({ a: 1 }, {
+            encoder: function (str, defaultEncoder) {
+                st.equal(defaultEncoder, utils.encode);
+            }
+        });
+
+        st.end();
+    });
+
+    t.test('throws error with wrong encoder', function (st) {
+        st['throws'](function () {
+            qs.stringify({}, { encoder: 'string' });
+        }, new TypeError('Encoder has to be a function.'));
+        st.end();
+    });
+
+    t.test('can use custom encoder for a buffer object', { skip: typeof Buffer === 'undefined' }, function (st) {
+        st.equal(qs.stringify({ a: SaferBuffer.from([1]) }, {
+            encoder: function (buffer) {
+                if (typeof buffer === 'string') {
+                    return buffer;
+                }
+                return String.fromCharCode(buffer.readUInt8(0) + 97);
+            }
+        }), 'a=b');
+
+        st.equal(qs.stringify({ a: SaferBuffer.from('a b') }, {
+            encoder: function (buffer) {
+                return buffer;
+            }
+        }), 'a=a b');
+        st.end();
+    });
+
+    t.test('serializeDate option', function (st) {
+        var date = new Date();
+        st.equal(
+            qs.stringify({ a: date }),
+            'a=' + date.toISOString().replace(/:/g, '%3A'),
+            'default is toISOString'
+        );
+
+        var mutatedDate = new Date();
+        mutatedDate.toISOString = function () {
+            throw new SyntaxError();
+        };
+        st['throws'](function () {
+            mutatedDate.toISOString();
+        }, SyntaxError);
+        st.equal(
+            qs.stringify({ a: mutatedDate }),
+            'a=' + Date.prototype.toISOString.call(mutatedDate).replace(/:/g, '%3A'),
+            'toISOString works even when method is not locally present'
+        );
+
+        var specificDate = new Date(6);
+        st.equal(
+            qs.stringify(
+                { a: specificDate },
+                { serializeDate: function (d) { return d.getTime() * 7; } }
+            ),
+            'a=42',
+            'custom serializeDate function called'
+        );
+
+        st.equal(
+            qs.stringify(
+                { a: [date] },
+                {
+                    serializeDate: function (d) { return d.getTime(); },
+                    arrayFormat: 'comma'
+                }
+            ),
+            'a=' + date.getTime(),
+            'works with arrayFormat comma'
+        );
+        st.equal(
+            qs.stringify(
+                { a: [date] },
+                {
+                    serializeDate: function (d) { return d.getTime(); },
+                    arrayFormat: 'comma',
+                    commaRoundTrip: true
+                }
+            ),
+            'a%5B%5D=' + date.getTime(),
+            'works with arrayFormat comma'
+        );
+
+        st.end();
+    });
+
+    t.test('RFC 1738 serialization', function (st) {
+        st.equal(qs.stringify({ a: 'b c' }, { format: qs.formats.RFC1738 }), 'a=b+c');
+        st.equal(qs.stringify({ 'a b': 'c d' }, { format: qs.formats.RFC1738 }), 'a+b=c+d');
+        st.equal(qs.stringify({ 'a b': SaferBuffer.from('a b') }, { format: qs.formats.RFC1738 }), 'a+b=a+b');
+
+        st.equal(qs.stringify({ 'foo(ref)': 'bar' }, { format: qs.formats.RFC1738 }), 'foo(ref)=bar');
+
+        st.end();
+    });
+
+    t.test('RFC 3986 spaces serialization', function (st) {
+        st.equal(qs.stringify({ a: 'b c' }, { format: qs.formats.RFC3986 }), 'a=b%20c');
+        st.equal(qs.stringify({ 'a b': 'c d' }, { format: qs.formats.RFC3986 }), 'a%20b=c%20d');
+        st.equal(qs.stringify({ 'a b': SaferBuffer.from('a b') }, { format: qs.formats.RFC3986 }), 'a%20b=a%20b');
+
+        st.end();
+    });
+
+    t.test('Backward compatibility to RFC 3986', function (st) {
+        st.equal(qs.stringify({ a: 'b c' }), 'a=b%20c');
+        st.equal(qs.stringify({ 'a b': SaferBuffer.from('a b') }), 'a%20b=a%20b');
+
+        st.end();
+    });
+
+    t.test('Edge cases and unknown formats', function (st) {
+        ['UFO1234', false, 1234, null, {}, []].forEach(function (format) {
+            st['throws'](
+                function () {
+                    qs.stringify({ a: 'b c' }, { format: format });
+                },
+                new TypeError('Unknown format option provided.')
+            );
+        });
+        st.end();
+    });
+
+    t.test('encodeValuesOnly', function (st) {
+        st.equal(
+            qs.stringify(
+                { a: 'b', c: ['d', 'e=f'], f: [['g'], ['h']] },
+                { encodeValuesOnly: true, arrayFormat: 'indices' }
+            ),
+            'a=b&c[0]=d&c[1]=e%3Df&f[0][0]=g&f[1][0]=h',
+            'encodeValuesOnly + indices'
+        );
+        st.equal(
+            qs.stringify(
+                { a: 'b', c: ['d', 'e=f'], f: [['g'], ['h']] },
+                { encodeValuesOnly: true, arrayFormat: 'brackets' }
+            ),
+            'a=b&c[]=d&c[]=e%3Df&f[][]=g&f[][]=h',
+            'encodeValuesOnly + brackets'
+        );
+        st.equal(
+            qs.stringify(
+                { a: 'b', c: ['d', 'e=f'], f: [['g'], ['h']] },
+                { encodeValuesOnly: true, arrayFormat: 'repeat' }
+            ),
+            'a=b&c=d&c=e%3Df&f=g&f=h',
+            'encodeValuesOnly + repeat'
+        );
+
+        st.equal(
+            qs.stringify(
+                { a: 'b', c: ['d', 'e'], f: [['g'], ['h']] },
+                { arrayFormat: 'indices' }
+            ),
+            'a=b&c%5B0%5D=d&c%5B1%5D=e&f%5B0%5D%5B0%5D=g&f%5B1%5D%5B0%5D=h',
+            'no encodeValuesOnly + indices'
+        );
+        st.equal(
+            qs.stringify(
+                { a: 'b', c: ['d', 'e'], f: [['g'], ['h']] },
+                { arrayFormat: 'brackets' }
+            ),
+            'a=b&c%5B%5D=d&c%5B%5D=e&f%5B%5D%5B%5D=g&f%5B%5D%5B%5D=h',
+            'no encodeValuesOnly + brackets'
+        );
+        st.equal(
+            qs.stringify(
+                { a: 'b', c: ['d', 'e'], f: [['g'], ['h']] },
+                { arrayFormat: 'repeat' }
+            ),
+            'a=b&c=d&c=e&f=g&f=h',
+            'no encodeValuesOnly + repeat'
+        );
+
+        st.end();
+    });
+
+    t.test('encodeValuesOnly - strictNullHandling', function (st) {
+        st.equal(
+            qs.stringify(
+                { a: { b: null } },
+                { encodeValuesOnly: true, strictNullHandling: true }
+            ),
+            'a[b]'
+        );
+        st.end();
+    });
+
+    t.test('throws if an invalid charset is specified', function (st) {
+        st['throws'](function () {
+            qs.stringify({ a: 'b' }, { charset: 'foobar' });
+        }, new TypeError('The charset option must be either utf-8, iso-8859-1, or undefined'));
+        st.end();
+    });
+
+    t.test('respects a charset of iso-8859-1', function (st) {
+        st.equal(qs.stringify({ æ: 'æ' }, { charset: 'iso-8859-1' }), '%E6=%E6');
+        st.end();
+    });
+
+    t.test('encodes unrepresentable chars as numeric entities in iso-8859-1 mode', function (st) {
+        st.equal(qs.stringify({ a: '☺' }, { charset: 'iso-8859-1' }), 'a=%26%239786%3B');
+        st.end();
+    });
+
+    t.test('respects an explicit charset of utf-8 (the default)', function (st) {
+        st.equal(qs.stringify({ a: 'æ' }, { charset: 'utf-8' }), 'a=%C3%A6');
+        st.end();
+    });
+
+    t.test('`charsetSentinel` option', function (st) {
+        st.equal(
+            qs.stringify({ a: 'æ' }, { charsetSentinel: true, charset: 'utf-8' }),
+            'utf8=%E2%9C%93&a=%C3%A6',
+            'adds the right sentinel when instructed to and the charset is utf-8'
+        );
+
+        st.equal(
+            qs.stringify({ a: 'æ' }, { charsetSentinel: true, charset: 'iso-8859-1' }),
+            'utf8=%26%2310003%3B&a=%E6',
+            'adds the right sentinel when instructed to and the charset is iso-8859-1'
+        );
+
+        st.end();
+    });
+
+    t.test('does not mutate the options argument', function (st) {
+        var options = {};
+        qs.stringify({}, options);
+        st.deepEqual(options, {});
+        st.end();
+    });
+
+    t.test('strictNullHandling works with custom filter', function (st) {
+        var filter = function (prefix, value) {
+            return value;
+        };
+
+        var options = { strictNullHandling: true, filter: filter };
+        st.equal(qs.stringify({ key: null }, options), 'key');
+        st.end();
+    });
+
+    t.test('strictNullHandling works with null serializeDate', function (st) {
+        var serializeDate = function () {
+            return null;
+        };
+        var options = { strictNullHandling: true, serializeDate: serializeDate };
+        var date = new Date();
+        st.equal(qs.stringify({ key: date }, options), 'key');
+        st.end();
+    });
+
+    t.test('allows for encoding keys and values differently', function (st) {
+        var encoder = function (str, defaultEncoder, charset, type) {
+            if (type === 'key') {
+                return defaultEncoder(str, defaultEncoder, charset, type).toLowerCase();
+            }
+            if (type === 'value') {
+                return defaultEncoder(str, defaultEncoder, charset, type).toUpperCase();
+            }
+            throw 'this should never happen! type: ' + type;
+        };
+
+        st.deepEqual(qs.stringify({ KeY: 'vAlUe' }, { encoder: encoder }), 'key=VALUE');
+        st.end();
+    });
+
+    t.test('objects inside arrays', function (st) {
+        var obj = { a: { b: { c: 'd', e: 'f' } } };
+        var withArray = { a: { b: [{ c: 'd', e: 'f' }] } };
+
+        st.equal(qs.stringify(obj, { encode: false }), 'a[b][c]=d&a[b][e]=f', 'no array, no arrayFormat');
+        st.equal(qs.stringify(obj, { encode: false, arrayFormat: 'brackets' }), 'a[b][c]=d&a[b][e]=f', 'no array, bracket');
+        st.equal(qs.stringify(obj, { encode: false, arrayFormat: 'indices' }), 'a[b][c]=d&a[b][e]=f', 'no array, indices');
+        st.equal(qs.stringify(obj, { encode: false, arrayFormat: 'repeat' }), 'a[b][c]=d&a[b][e]=f', 'no array, repeat');
+        st.equal(qs.stringify(obj, { encode: false, arrayFormat: 'comma' }), 'a[b][c]=d&a[b][e]=f', 'no array, comma');
+
+        st.equal(qs.stringify(withArray, { encode: false }), 'a[b][0][c]=d&a[b][0][e]=f', 'array, no arrayFormat');
+        st.equal(qs.stringify(withArray, { encode: false, arrayFormat: 'brackets' }), 'a[b][][c]=d&a[b][][e]=f', 'array, bracket');
+        st.equal(qs.stringify(withArray, { encode: false, arrayFormat: 'indices' }), 'a[b][0][c]=d&a[b][0][e]=f', 'array, indices');
+        st.equal(qs.stringify(withArray, { encode: false, arrayFormat: 'repeat' }), 'a[b][c]=d&a[b][e]=f', 'array, repeat');
+        st.equal(
+            qs.stringify(withArray, { encode: false, arrayFormat: 'comma' }),
+            '???',
+            'array, comma',
+            { skip: 'TODO: figure out what this should do' }
+        );
+
+        st.end();
+    });
+
+    t.test('stringifies sparse arrays', function (st) {
+        /* eslint no-sparse-arrays: 0 */
+        st.equal(qs.stringify({ a: [, '2', , , '1'] }, { encodeValuesOnly: true, arrayFormat: 'indices' }), 'a[1]=2&a[4]=1');
+        st.equal(qs.stringify({ a: [, '2', , , '1'] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a[]=2&a[]=1');
+        st.equal(qs.stringify({ a: [, '2', , , '1'] }, { encodeValuesOnly: true, arrayFormat: 'repeat' }), 'a=2&a=1');
+
+        st.equal(qs.stringify({ a: [, { b: [, , { c: '1' }] }] }, { encodeValuesOnly: true, arrayFormat: 'indices' }), 'a[1][b][2][c]=1');
+        st.equal(qs.stringify({ a: [, { b: [, , { c: '1' }] }] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a[][b][][c]=1');
+        st.equal(qs.stringify({ a: [, { b: [, , { c: '1' }] }] }, { encodeValuesOnly: true, arrayFormat: 'repeat' }), 'a[b][c]=1');
+
+        st.equal(qs.stringify({ a: [, [, , [, , , { c: '1' }]]] }, { encodeValuesOnly: true, arrayFormat: 'indices' }), 'a[1][2][3][c]=1');
+        st.equal(qs.stringify({ a: [, [, , [, , , { c: '1' }]]] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a[][][][c]=1');
+        st.equal(qs.stringify({ a: [, [, , [, , , { c: '1' }]]] }, { encodeValuesOnly: true, arrayFormat: 'repeat' }), 'a[c]=1');
+
+        st.equal(qs.stringify({ a: [, [, , [, , , { c: [, '1'] }]]] }, { encodeValuesOnly: true, arrayFormat: 'indices' }), 'a[1][2][3][c][1]=1');
+        st.equal(qs.stringify({ a: [, [, , [, , , { c: [, '1'] }]]] }, { encodeValuesOnly: true, arrayFormat: 'brackets' }), 'a[][][][c][]=1');
+        st.equal(qs.stringify({ a: [, [, , [, , , { c: [, '1'] }]]] }, { encodeValuesOnly: true, arrayFormat: 'repeat' }), 'a[c]=1');
+
+        st.end();
+    });
+
+    t.test('encodes a very long string', function (st) {
+        var chars = [];
+        var expected = [];
+        for (var i = 0; i < 5e3; i++) {
+            chars.push(' ' + i);
+
+            expected.push('%20' + i);
+        }
+
+        var obj = {
+            foo: chars.join('')
+        };
+
+        st.equal(
+            qs.stringify(obj, { arrayFormat: 'brackets', charset: 'utf-8' }),
+            'foo=' + expected.join('')
+        );
+
+        st.end();
+    });
+
+    t.end();
+});
+
+test('stringifies empty keys', function (t) {
+    emptyTestCases.forEach(function (testCase) {
+        t.test('stringifies an object with empty string key with ' + testCase.input, function (st) {
+            st.deepEqual(
+                qs.stringify(testCase.withEmptyKeys, { encode: false, arrayFormat: 'indices' }),
+                testCase.stringifyOutput.indices,
+                'test case: ' + testCase.input + ', indices'
+            );
+            st.deepEqual(
+                qs.stringify(testCase.withEmptyKeys, { encode: false, arrayFormat: 'brackets' }),
+                testCase.stringifyOutput.brackets,
+                'test case: ' + testCase.input + ', brackets'
+            );
+            st.deepEqual(
+                qs.stringify(testCase.withEmptyKeys, { encode: false, arrayFormat: 'repeat' }),
+                testCase.stringifyOutput.repeat,
+                'test case: ' + testCase.input + ', repeat'
+            );
+
+            st.end();
+        });
+    });
+
+    t.test('edge case with object/arrays', function (st) {
+        st.deepEqual(qs.stringify({ '': { '': [2, 3] } }, { encode: false }), '[][0]=2&[][1]=3');
+        st.deepEqual(qs.stringify({ '': { '': [2, 3], a: 2 } }, { encode: false }), '[][0]=2&[][1]=3&[a]=2');
+        st.deepEqual(qs.stringify({ '': { '': [2, 3] } }, { encode: false, arrayFormat: 'indices' }), '[][0]=2&[][1]=3');
+        st.deepEqual(qs.stringify({ '': { '': [2, 3], a: 2 } }, { encode: false, arrayFormat: 'indices' }), '[][0]=2&[][1]=3&[a]=2');
+
+        st.end();
+    });
+
+    t.test('stringifies non-string keys', function (st) {
+        var S = Object('abc');
+        S.toString = function () {
+            return 'd';
+        };
+        var actual = qs.stringify({ a: 'b', 'false': {}, 1e+22: 'c', d: 'e' }, {
+            filter: ['a', false, null, 10000000000000000000000, S],
+            allowDots: true,
+            encodeDotInKeys: true
+        });
+
+        st.equal(actual, 'a=b&1e%2B22=c&d=e', 'stringifies correctly');
+
+        st.end();
+    });
+});
diff --git a/server/node_modules/qs/test/utils.js b/server/node_modules/qs/test/utils.js
new file mode 100644
index 0000000..defb7f2
--- /dev/null
+++ b/server/node_modules/qs/test/utils.js
@@ -0,0 +1,381 @@
+'use strict';
+
+var test = require('tape');
+var inspect = require('object-inspect');
+var SaferBuffer = require('safer-buffer').Buffer;
+var forEach = require('for-each');
+var v = require('es-value-fixtures');
+
+var utils = require('../lib/utils');
+
+test('merge()', function (t) {
+    t.deepEqual(utils.merge(null, true), [null, true], 'merges true into null');
+
+    t.deepEqual(utils.merge(null, [42]), [null, 42], 'merges null into an array');
+
+    t.deepEqual(utils.merge({ a: 'b' }, { a: 'c' }), { a: ['b', 'c'] }, 'merges two objects with the same key');
+
+    var oneMerged = utils.merge({ foo: 'bar' }, { foo: { first: '123' } });
+    t.deepEqual(oneMerged, { foo: ['bar', { first: '123' }] }, 'merges a standalone and an object into an array');
+
+    var twoMerged = utils.merge({ foo: ['bar', { first: '123' }] }, { foo: { second: '456' } });
+    t.deepEqual(twoMerged, { foo: { 0: 'bar', 1: { first: '123' }, second: '456' } }, 'merges a standalone and two objects into an array');
+
+    var sandwiched = utils.merge({ foo: ['bar', { first: '123', second: '456' }] }, { foo: 'baz' });
+    t.deepEqual(sandwiched, { foo: ['bar', { first: '123', second: '456' }, 'baz'] }, 'merges an object sandwiched by two standalones into an array');
+
+    var nestedArrays = utils.merge({ foo: ['baz'] }, { foo: ['bar', 'xyzzy'] });
+    t.deepEqual(nestedArrays, { foo: ['baz', 'bar', 'xyzzy'] });
+
+    var noOptionsNonObjectSource = utils.merge({ foo: 'baz' }, 'bar');
+    t.deepEqual(noOptionsNonObjectSource, { foo: 'baz', bar: true });
+
+    var func = function f() {};
+    t.deepEqual(
+        utils.merge(func, { foo: 'bar' }),
+        [func, { foo: 'bar' }],
+        'functions can not be merged into'
+    );
+
+    func.bar = 'baz';
+    t.deepEqual(
+        utils.merge({ foo: 'bar' }, func),
+        { foo: 'bar', bar: 'baz' },
+        'functions can be merge sources'
+    );
+
+    t.test(
+        'avoids invoking array setters unnecessarily',
+        { skip: typeof Object.defineProperty !== 'function' },
+        function (st) {
+            var setCount = 0;
+            var getCount = 0;
+            var observed = [];
+            Object.defineProperty(observed, 0, {
+                get: function () {
+                    getCount += 1;
+                    return { bar: 'baz' };
+                },
+                set: function () { setCount += 1; }
+            });
+            utils.merge(observed, [null]);
+            st.equal(setCount, 0);
+            st.equal(getCount, 1);
+            observed[0] = observed[0]; // eslint-disable-line no-self-assign
+            st.equal(setCount, 1);
+            st.equal(getCount, 2);
+            st.end();
+        }
+    );
+
+    t.test('with overflow objects (from arrayLimit)', function (st) {
+        st.test('merges primitive into overflow object at next index', function (s2t) {
+            // Create an overflow object via combine
+            var overflow = utils.combine(['a'], 'b', 1, false);
+            s2t.ok(utils.isOverflow(overflow), 'overflow object is marked');
+            var merged = utils.merge(overflow, 'c');
+            s2t.deepEqual(merged, { 0: 'a', 1: 'b', 2: 'c' }, 'adds primitive at next numeric index');
+            s2t.end();
+        });
+
+        st.test('merges primitive into regular object with numeric keys normally', function (s2t) {
+            var obj = { 0: 'a', 1: 'b' };
+            s2t.notOk(utils.isOverflow(obj), 'plain object is not marked as overflow');
+            var merged = utils.merge(obj, 'c');
+            s2t.deepEqual(merged, { 0: 'a', 1: 'b', c: true }, 'adds primitive as key (not at next index)');
+            s2t.end();
+        });
+
+        st.test('merges primitive into object with non-numeric keys normally', function (s2t) {
+            var obj = { foo: 'bar' };
+            var merged = utils.merge(obj, 'baz');
+            s2t.deepEqual(merged, { foo: 'bar', baz: true }, 'adds primitive as key with value true');
+            s2t.end();
+        });
+
+        st.test('merges overflow object into primitive', function (s2t) {
+            // Create an overflow object via combine
+            var overflow = utils.combine([], 'b', 0, false);
+            s2t.ok(utils.isOverflow(overflow), 'overflow object is marked');
+            var merged = utils.merge('a', overflow);
+            s2t.ok(utils.isOverflow(merged), 'result is also marked as overflow');
+            s2t.deepEqual(merged, { 0: 'a', 1: 'b' }, 'creates object with primitive at 0, source values shifted');
+            s2t.end();
+        });
+
+        st.test('merges overflow object with multiple values into primitive', function (s2t) {
+            // Create an overflow object via combine
+            var overflow = utils.combine(['b'], 'c', 1, false);
+            s2t.ok(utils.isOverflow(overflow), 'overflow object is marked');
+            var merged = utils.merge('a', overflow);
+            s2t.deepEqual(merged, { 0: 'a', 1: 'b', 2: 'c' }, 'shifts all source indices by 1');
+            s2t.end();
+        });
+
+        st.test('merges regular object into primitive as array', function (s2t) {
+            var obj = { foo: 'bar' };
+            var merged = utils.merge('a', obj);
+            s2t.deepEqual(merged, ['a', { foo: 'bar' }], 'creates array with primitive and object');
+            s2t.end();
+        });
+
+        st.end();
+    });
+
+    t.end();
+});
+
+test('assign()', function (t) {
+    var target = { a: 1, b: 2 };
+    var source = { b: 3, c: 4 };
+    var result = utils.assign(target, source);
+
+    t.equal(result, target, 'returns the target');
+    t.deepEqual(target, { a: 1, b: 3, c: 4 }, 'target and source are merged');
+    t.deepEqual(source, { b: 3, c: 4 }, 'source is untouched');
+
+    t.end();
+});
+
+test('combine()', function (t) {
+    t.test('both arrays', function (st) {
+        var a = [1];
+        var b = [2];
+        var combined = utils.combine(a, b);
+
+        st.deepEqual(a, [1], 'a is not mutated');
+        st.deepEqual(b, [2], 'b is not mutated');
+        st.notEqual(a, combined, 'a !== combined');
+        st.notEqual(b, combined, 'b !== combined');
+        st.deepEqual(combined, [1, 2], 'combined is a + b');
+
+        st.end();
+    });
+
+    t.test('one array, one non-array', function (st) {
+        var aN = 1;
+        var a = [aN];
+        var bN = 2;
+        var b = [bN];
+
+        var combinedAnB = utils.combine(aN, b);
+        st.deepEqual(b, [bN], 'b is not mutated');
+        st.notEqual(aN, combinedAnB, 'aN + b !== aN');
+        st.notEqual(a, combinedAnB, 'aN + b !== a');
+        st.notEqual(bN, combinedAnB, 'aN + b !== bN');
+        st.notEqual(b, combinedAnB, 'aN + b !== b');
+        st.deepEqual([1, 2], combinedAnB, 'first argument is array-wrapped when not an array');
+
+        var combinedABn = utils.combine(a, bN);
+        st.deepEqual(a, [aN], 'a is not mutated');
+        st.notEqual(aN, combinedABn, 'a + bN !== aN');
+        st.notEqual(a, combinedABn, 'a + bN !== a');
+        st.notEqual(bN, combinedABn, 'a + bN !== bN');
+        st.notEqual(b, combinedABn, 'a + bN !== b');
+        st.deepEqual([1, 2], combinedABn, 'second argument is array-wrapped when not an array');
+
+        st.end();
+    });
+
+    t.test('neither is an array', function (st) {
+        var combined = utils.combine(1, 2);
+        st.notEqual(1, combined, '1 + 2 !== 1');
+        st.notEqual(2, combined, '1 + 2 !== 2');
+        st.deepEqual([1, 2], combined, 'both arguments are array-wrapped when not an array');
+
+        st.end();
+    });
+
+    t.test('with arrayLimit', function (st) {
+        st.test('under the limit', function (s2t) {
+            var combined = utils.combine(['a', 'b'], 'c', 10, false);
+            s2t.deepEqual(combined, ['a', 'b', 'c'], 'returns array when under limit');
+            s2t.ok(Array.isArray(combined), 'result is an array');
+            s2t.end();
+        });
+
+        st.test('exactly at the limit stays as array', function (s2t) {
+            var combined = utils.combine(['a', 'b'], 'c', 3, false);
+            s2t.deepEqual(combined, ['a', 'b', 'c'], 'stays as array when exactly at limit');
+            s2t.ok(Array.isArray(combined), 'result is an array');
+            s2t.end();
+        });
+
+        st.test('over the limit', function (s2t) {
+            var combined = utils.combine(['a', 'b', 'c'], 'd', 3, false);
+            s2t.deepEqual(combined, { 0: 'a', 1: 'b', 2: 'c', 3: 'd' }, 'converts to object when over limit');
+            s2t.notOk(Array.isArray(combined), 'result is not an array');
+            s2t.end();
+        });
+
+        st.test('with arrayLimit 0', function (s2t) {
+            var combined = utils.combine([], 'a', 0, false);
+            s2t.deepEqual(combined, { 0: 'a' }, 'converts single element to object with arrayLimit 0');
+            s2t.notOk(Array.isArray(combined), 'result is not an array');
+            s2t.end();
+        });
+
+        st.test('with plainObjects option', function (s2t) {
+            var combined = utils.combine(['a'], 'b', 1, true);
+            var expected = { __proto__: null, 0: 'a', 1: 'b' };
+            s2t.deepEqual(combined, expected, 'converts to object with null prototype');
+            s2t.equal(Object.getPrototypeOf(combined), null, 'result has null prototype when plainObjects is true');
+            s2t.end();
+        });
+
+        st.end();
+    });
+
+    t.test('with existing overflow object', function (st) {
+        st.test('adds to existing overflow object at next index', function (s2t) {
+            // Create overflow object first via combine
+            var overflow = utils.combine(['a'], 'b', 1, false);
+            s2t.ok(utils.isOverflow(overflow), 'initial object is marked as overflow');
+
+            var combined = utils.combine(overflow, 'c', 10, false);
+            s2t.equal(combined, overflow, 'returns the same object (mutated)');
+            s2t.deepEqual(combined, { 0: 'a', 1: 'b', 2: 'c' }, 'adds value at next numeric index');
+            s2t.end();
+        });
+
+        st.test('does not treat plain object with numeric keys as overflow', function (s2t) {
+            var plainObj = { 0: 'a', 1: 'b' };
+            s2t.notOk(utils.isOverflow(plainObj), 'plain object is not marked as overflow');
+
+            // combine treats this as a regular value, not an overflow object to append to
+            var combined = utils.combine(plainObj, 'c', 10, false);
+            s2t.deepEqual(combined, [{ 0: 'a', 1: 'b' }, 'c'], 'concatenates as regular values');
+            s2t.end();
+        });
+
+        st.end();
+    });
+
+    t.end();
+});
+
+test('decode', function (t) {
+    t.equal(
+        utils.decode('a+b'),
+        'a b',
+        'decodes + to space'
+    );
+
+    t.equal(
+        utils.decode('name%2Eobj'),
+        'name.obj',
+        'decodes a string'
+    );
+    t.equal(
+        utils.decode('name%2Eobj%2Efoo', null, 'iso-8859-1'),
+        'name.obj.foo',
+        'decodes a string in iso-8859-1'
+    );
+
+    t.end();
+});
+
+test('encode', function (t) {
+    forEach(v.nullPrimitives, function (nullish) {
+        t['throws'](
+            function () { utils.encode(nullish); },
+            TypeError,
+            inspect(nullish) + ' is not a string'
+        );
+    });
+
+    t.equal(utils.encode(''), '', 'empty string returns itself');
+    t.deepEqual(utils.encode([]), [], 'empty array returns itself');
+    t.deepEqual(utils.encode({ length: 0 }), { length: 0 }, 'empty arraylike returns itself');
+
+    t.test('symbols', { skip: !v.hasSymbols }, function (st) {
+        st.equal(utils.encode(Symbol('x')), 'Symbol%28x%29', 'symbol is encoded');
+
+        st.end();
+    });
+
+    t.equal(
+        utils.encode('(abc)'),
+        '%28abc%29',
+        'encodes parentheses'
+    );
+    t.equal(
+        utils.encode({ toString: function () { return '(abc)'; } }),
+        '%28abc%29',
+        'toStrings and encodes parentheses'
+    );
+
+    t.equal(
+        utils.encode('abc 123 💩', null, 'iso-8859-1'),
+        'abc%20123%20%26%2355357%3B%26%2356489%3B',
+        'encodes in iso-8859-1'
+    );
+
+    var longString = '';
+    var expectedString = '';
+    for (var i = 0; i < 1500; i++) {
+        longString += ' ';
+        expectedString += '%20';
+    }
+
+    t.equal(
+        utils.encode(longString),
+        expectedString,
+        'encodes a long string'
+    );
+
+    t.equal(
+        utils.encode('\x28\x29'),
+        '%28%29',
+        'encodes parens normally'
+    );
+    t.equal(
+        utils.encode('\x28\x29', null, null, null, 'RFC1738'),
+        '()',
+        'does not encode parens in RFC1738'
+    );
+
+    // todo RFC1738 format
+
+    t.equal(
+        utils.encode('Āက豈'),
+        '%C4%80%E1%80%80%EF%A4%80',
+        'encodes multibyte chars'
+    );
+
+    t.equal(
+        utils.encode('\uD83D \uDCA9'),
+        '%F0%9F%90%A0%F0%BA%90%80',
+        'encodes lone surrogates'
+    );
+
+    t.end();
+});
+
+test('isBuffer()', function (t) {
+    forEach([null, undefined, true, false, '', 'abc', 42, 0, NaN, {}, [], function () {}, /a/g], function (x) {
+        t.equal(utils.isBuffer(x), false, inspect(x) + ' is not a buffer');
+    });
+
+    var fakeBuffer = { constructor: Buffer };
+    t.equal(utils.isBuffer(fakeBuffer), false, 'fake buffer is not a buffer');
+
+    var saferBuffer = SaferBuffer.from('abc');
+    t.equal(utils.isBuffer(saferBuffer), true, 'SaferBuffer instance is a buffer');
+
+    var buffer = Buffer.from && Buffer.alloc ? Buffer.from('abc') : new Buffer('abc');
+    t.equal(utils.isBuffer(buffer), true, 'real Buffer instance is a buffer');
+    t.end();
+});
+
+test('isRegExp()', function (t) {
+    t.equal(utils.isRegExp(/a/g), true, 'RegExp is a RegExp');
+    t.equal(utils.isRegExp(new RegExp('a', 'g')), true, 'new RegExp is a RegExp');
+    t.equal(utils.isRegExp(new Date()), false, 'Date is not a RegExp');
+
+    forEach(v.primitives, function (primitive) {
+        t.equal(utils.isRegExp(primitive), false, inspect(primitive) + ' is not a RegExp');
+    });
+
+    t.end();
+});
diff --git a/server/node_modules/random-bytes/HISTORY.md b/server/node_modules/random-bytes/HISTORY.md
new file mode 100644
index 0000000..8cabd9d
--- /dev/null
+++ b/server/node_modules/random-bytes/HISTORY.md
@@ -0,0 +1,4 @@
+1.0.0 / 2016-01-17
+==================
+
+  * Initial release
diff --git a/server/node_modules/random-bytes/LICENSE b/server/node_modules/random-bytes/LICENSE
new file mode 100644
index 0000000..c24dbe3
--- /dev/null
+++ b/server/node_modules/random-bytes/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/random-bytes/README.md b/server/node_modules/random-bytes/README.md
new file mode 100644
index 0000000..df5aacc
--- /dev/null
+++ b/server/node_modules/random-bytes/README.md
@@ -0,0 +1,77 @@
+# random-bytes
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Generate strong pseudo-random bytes.
+
+This module is a simple wrapper around the Node.js core `crypto.randomBytes` API,
+with the following additions:
+
+  * A `Promise` interface for environments with promises.
+  * For Node.js versions that do not wait for the PRNG to be seeded, this module
+    will wait a bit.
+
+## Installation
+
+```sh
+$ npm install random-bytes
+```
+
+## API
+
+```js
+var randomBytes = require('random-bytes')
+```
+
+### randomBytes(size, callback)
+
+Generates strong pseudo-random bytes. The `size` argument is a number indicating
+the number of bytes to generate.
+
+```js
+randomBytes(12, function (error, bytes) {
+  if (error) throw error
+  // do something with the bytes
+})
+```
+
+### randomBytes(size)
+
+Generates strong pseudo-random bytes and return a `Promise`. The `size` argument is
+a number indicating the number of bytes to generate.
+
+**Note**: To use promises in Node.js _prior to 0.12_, promises must be
+"polyfilled" using `global.Promise = require('bluebird')`.
+
+```js
+randomBytes(18).then(function (string) {
+  // do something with the string
+})
+```
+
+### randomBytes.sync(size)
+
+A synchronous version of above.
+
+```js
+var bytes = randomBytes.sync(18)
+```
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/random-bytes.svg
+[npm-url]: https://npmjs.org/package/random-bytes
+[node-version-image]: https://img.shields.io/node/v/random-bytes.svg
+[node-version-url]: http://nodejs.org/download/
+[travis-image]: https://img.shields.io/travis/crypto-utils/random-bytes/master.svg
+[travis-url]: https://travis-ci.org/crypto-utils/random-bytes
+[coveralls-image]: https://img.shields.io/coveralls/crypto-utils/random-bytes/master.svg
+[coveralls-url]: https://coveralls.io/r/crypto-utils/random-bytes?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/random-bytes.svg
+[downloads-url]: https://npmjs.org/package/random-bytes
diff --git a/server/node_modules/random-bytes/index.js b/server/node_modules/random-bytes/index.js
new file mode 100644
index 0000000..9ad930f
--- /dev/null
+++ b/server/node_modules/random-bytes/index.js
@@ -0,0 +1,101 @@
+/*!
+ * random-bytes
+ * Copyright(c) 2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var crypto = require('crypto')
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var generateAttempts = crypto.randomBytes === crypto.pseudoRandomBytes ? 1 : 3
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = randomBytes
+module.exports.sync = randomBytesSync
+
+/**
+ * Generates strong pseudo-random bytes.
+ *
+ * @param {number} size
+ * @param {function} [callback]
+ * @return {Promise}
+ * @public
+ */
+
+function randomBytes(size, callback) {
+  // validate callback is a function, if provided
+  if (callback !== undefined && typeof callback !== 'function') {
+    throw new TypeError('argument callback must be a function')
+  }
+
+  // require the callback without promises
+  if (!callback && !global.Promise) {
+    throw new TypeError('argument callback is required')
+  }
+
+  if (callback) {
+    // classic callback style
+    return generateRandomBytes(size, generateAttempts, callback)
+  }
+
+  return new Promise(function executor(resolve, reject) {
+    generateRandomBytes(size, generateAttempts, function onRandomBytes(err, str) {
+      if (err) return reject(err)
+      resolve(str)
+    })
+  })
+}
+
+/**
+ * Generates strong pseudo-random bytes sync.
+ *
+ * @param {number} size
+ * @return {Buffer}
+ * @public
+ */
+
+function randomBytesSync(size) {
+  var err = null
+
+  for (var i = 0; i < generateAttempts; i++) {
+    try {
+      return crypto.randomBytes(size)
+    } catch (e) {
+      err = e
+    }
+  }
+
+  throw err
+}
+
+/**
+ * Generates strong pseudo-random bytes.
+ *
+ * @param {number} size
+ * @param {number} attempts
+ * @param {function} callback
+ * @private
+ */
+
+function generateRandomBytes(size, attempts, callback) {
+  crypto.randomBytes(size, function onRandomBytes(err, buf) {
+    if (!err) return callback(null, buf)
+    if (!--attempts) return callback(err)
+    setTimeout(generateRandomBytes.bind(null, size, attempts, callback), 10)
+  })
+}
diff --git a/server/node_modules/random-bytes/package.json b/server/node_modules/random-bytes/package.json
new file mode 100644
index 0000000..c67e0e8
--- /dev/null
+++ b/server/node_modules/random-bytes/package.json
@@ -0,0 +1,36 @@
+{
+  "name": "random-bytes",
+  "description": "URL and cookie safe UIDs",
+  "version": "1.0.0",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>"
+  ],
+  "license": "MIT",
+  "repository": "crypto-utils/random-bytes",
+  "devDependencies": {
+    "bluebird": "3.1.1",
+    "istanbul": "0.4.2",
+    "mocha": "2.3.4",
+    "proxyquire": "1.2.0"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "test": "mocha --trace-deprecation --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --trace-deprecation --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --trace-deprecation --reporter spec --check-leaks test/"
+  },
+  "keywords": [
+    "bytes",
+    "generator",
+    "random",
+    "safe"
+  ]
+}
diff --git a/server/node_modules/range-parser/HISTORY.md b/server/node_modules/range-parser/HISTORY.md
new file mode 100644
index 0000000..70a973d
--- /dev/null
+++ b/server/node_modules/range-parser/HISTORY.md
@@ -0,0 +1,56 @@
+1.2.1 / 2019-05-10
+==================
+
+  * Improve error when `str` is not a string
+
+1.2.0 / 2016-06-01
+==================
+
+  * Add `combine` option to combine overlapping ranges
+
+1.1.0 / 2016-05-13
+==================
+
+  * Fix incorrectly returning -1 when there is at least one valid range
+  * perf: remove internal function
+
+1.0.3 / 2015-10-29
+==================
+
+  * perf: enable strict mode
+
+1.0.2 / 2014-09-08
+==================
+
+  * Support Node.js 0.6
+
+1.0.1 / 2014-09-07
+==================
+
+  * Move repository to jshttp
+
+1.0.0 / 2013-12-11
+==================
+
+  * Add repository to package.json
+  * Add MIT license
+
+0.0.4 / 2012-06-17
+==================
+
+  * Change ret -1 for unsatisfiable and -2 when invalid
+
+0.0.3 / 2012-06-17
+==================
+
+  * Fix last-byte-pos default to len - 1
+
+0.0.2 / 2012-06-14
+==================
+
+  * Add `.type`
+
+0.0.1 / 2012-06-11
+==================
+
+  * Initial release
diff --git a/server/node_modules/range-parser/LICENSE b/server/node_modules/range-parser/LICENSE
new file mode 100644
index 0000000..3599954
--- /dev/null
+++ b/server/node_modules/range-parser/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2012-2014 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2015-2016 Douglas Christopher Wilson <doug@somethingdoug.com
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/range-parser/README.md b/server/node_modules/range-parser/README.md
new file mode 100644
index 0000000..c247e82
--- /dev/null
+++ b/server/node_modules/range-parser/README.md
@@ -0,0 +1,84 @@
+# range-parser
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Range header field parser.
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install range-parser
+```
+
+## API
+
+
+
+```js
+var parseRange = require('range-parser')
+```
+
+### parseRange(size, header, options)
+
+Parse the given `header` string where `size` is the maximum size of the resource.
+An array of ranges will be returned or negative numbers indicating an error parsing.
+
+  * `-2` signals a malformed header string
+  * `-1` signals an unsatisfiable range
+
+
+
+```js
+// parse header from request
+var range = parseRange(size, req.headers.range)
+
+// the type of the range
+if (range.type === 'bytes') {
+  // the ranges
+  range.forEach(function (r) {
+    // do something with r.start and r.end
+  })
+}
+```
+
+#### Options
+
+These properties are accepted in the options object.
+
+##### combine
+
+Specifies if overlapping & adjacent ranges should be combined, defaults to `false`.
+When `true`, ranges will be combined and returned as if they were specified that
+way in the header.
+
+
+
+```js
+parseRange(100, 'bytes=50-55,0-10,5-10,56-60', { combine: true })
+// => [
+//      { start: 0,  end: 10 },
+//      { start: 50, end: 60 }
+//    ]
+```
+
+## License
+
+[MIT](LICENSE)
+
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/range-parser/master
+[coveralls-url]: https://coveralls.io/r/jshttp/range-parser?branch=master
+[node-image]: https://badgen.net/npm/node/range-parser
+[node-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/range-parser
+[npm-url]: https://npmjs.org/package/range-parser
+[npm-version-image]: https://badgen.net/npm/v/range-parser
+[travis-image]: https://badgen.net/travis/jshttp/range-parser/master
+[travis-url]: https://travis-ci.org/jshttp/range-parser
diff --git a/server/node_modules/range-parser/index.js b/server/node_modules/range-parser/index.js
new file mode 100644
index 0000000..b7dc5c0
--- /dev/null
+++ b/server/node_modules/range-parser/index.js
@@ -0,0 +1,162 @@
+/*!
+ * range-parser
+ * Copyright(c) 2012-2014 TJ Holowaychuk
+ * Copyright(c) 2015-2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = rangeParser
+
+/**
+ * Parse "Range" header `str` relative to the given file `size`.
+ *
+ * @param {Number} size
+ * @param {String} str
+ * @param {Object} [options]
+ * @return {Array}
+ * @public
+ */
+
+function rangeParser (size, str, options) {
+  if (typeof str !== 'string') {
+    throw new TypeError('argument str must be a string')
+  }
+
+  var index = str.indexOf('=')
+
+  if (index === -1) {
+    return -2
+  }
+
+  // split the range string
+  var arr = str.slice(index + 1).split(',')
+  var ranges = []
+
+  // add ranges type
+  ranges.type = str.slice(0, index)
+
+  // parse all ranges
+  for (var i = 0; i < arr.length; i++) {
+    var range = arr[i].split('-')
+    var start = parseInt(range[0], 10)
+    var end = parseInt(range[1], 10)
+
+    // -nnn
+    if (isNaN(start)) {
+      start = size - end
+      end = size - 1
+    // nnn-
+    } else if (isNaN(end)) {
+      end = size - 1
+    }
+
+    // limit last-byte-pos to current length
+    if (end > size - 1) {
+      end = size - 1
+    }
+
+    // invalid or unsatisifiable
+    if (isNaN(start) || isNaN(end) || start > end || start < 0) {
+      continue
+    }
+
+    // add range
+    ranges.push({
+      start: start,
+      end: end
+    })
+  }
+
+  if (ranges.length < 1) {
+    // unsatisifiable
+    return -1
+  }
+
+  return options && options.combine
+    ? combineRanges(ranges)
+    : ranges
+}
+
+/**
+ * Combine overlapping & adjacent ranges.
+ * @private
+ */
+
+function combineRanges (ranges) {
+  var ordered = ranges.map(mapWithIndex).sort(sortByRangeStart)
+
+  for (var j = 0, i = 1; i < ordered.length; i++) {
+    var range = ordered[i]
+    var current = ordered[j]
+
+    if (range.start > current.end + 1) {
+      // next range
+      ordered[++j] = range
+    } else if (range.end > current.end) {
+      // extend range
+      current.end = range.end
+      current.index = Math.min(current.index, range.index)
+    }
+  }
+
+  // trim ordered array
+  ordered.length = j + 1
+
+  // generate combined range
+  var combined = ordered.sort(sortByRangeIndex).map(mapWithoutIndex)
+
+  // copy ranges type
+  combined.type = ranges.type
+
+  return combined
+}
+
+/**
+ * Map function to add index value to ranges.
+ * @private
+ */
+
+function mapWithIndex (range, index) {
+  return {
+    start: range.start,
+    end: range.end,
+    index: index
+  }
+}
+
+/**
+ * Map function to remove index value from ranges.
+ * @private
+ */
+
+function mapWithoutIndex (range) {
+  return {
+    start: range.start,
+    end: range.end
+  }
+}
+
+/**
+ * Sort function to sort ranges by index.
+ * @private
+ */
+
+function sortByRangeIndex (a, b) {
+  return a.index - b.index
+}
+
+/**
+ * Sort function to sort ranges by start position.
+ * @private
+ */
+
+function sortByRangeStart (a, b) {
+  return a.start - b.start
+}
diff --git a/server/node_modules/range-parser/package.json b/server/node_modules/range-parser/package.json
new file mode 100644
index 0000000..abea6d8
--- /dev/null
+++ b/server/node_modules/range-parser/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "range-parser",
+  "author": "TJ Holowaychuk <tj@vision-media.ca> (http://tjholowaychuk.com)",
+  "description": "Range header field string parser",
+  "version": "1.2.1",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "James Wyatt Cready <wyatt.cready@lanetix.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "range",
+    "parser",
+    "http"
+  ],
+  "repository": "jshttp/range-parser",
+  "devDependencies": {
+    "deep-equal": "1.0.1",
+    "eslint": "5.16.0",
+    "eslint-config-standard": "12.0.0",
+    "eslint-plugin-markdown": "1.0.0",
+    "eslint-plugin-import": "2.17.2",
+    "eslint-plugin-node": "8.0.1",
+    "eslint-plugin-promise": "4.1.1",
+    "eslint-plugin-standard": "4.0.0",
+    "mocha": "6.1.4",
+    "nyc": "14.1.1"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "test-travis": "nyc --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/raw-body/LICENSE b/server/node_modules/raw-body/LICENSE
new file mode 100644
index 0000000..1029a7a
--- /dev/null
+++ b/server/node_modules/raw-body/LICENSE
@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2013-2014 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2014-2022 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/raw-body/README.md b/server/node_modules/raw-body/README.md
new file mode 100644
index 0000000..d9b36d6
--- /dev/null
+++ b/server/node_modules/raw-body/README.md
@@ -0,0 +1,223 @@
+# raw-body
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build status][github-actions-ci-image]][github-actions-ci-url]
+[![Test coverage][coveralls-image]][coveralls-url]
+
+Gets the entire buffer of a stream either as a `Buffer` or a string.
+Validates the stream's length against an expected length and maximum limit.
+Ideal for parsing request bodies.
+
+## Install
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install raw-body
+```
+
+### TypeScript
+
+This module includes a [TypeScript](https://www.typescriptlang.org/)
+declaration file to enable auto complete in compatible editors and type
+information for TypeScript projects. This module depends on the Node.js
+types, so install `@types/node`:
+
+```sh
+$ npm install @types/node
+```
+
+## API
+
+```js
+var getRawBody = require('raw-body')
+```
+
+### getRawBody(stream, [options], [callback])
+
+**Returns a promise if no callback specified and global `Promise` exists.**
+
+Options:
+
+- `length` - The length of the stream.
+  If the contents of the stream do not add up to this length,
+  an `400` error code is returned.
+- `limit` - The byte limit of the body.
+  This is the number of bytes or any string format supported by
+  [bytes](https://www.npmjs.com/package/bytes),
+  for example `1000`, `'500kb'` or `'3mb'`.
+  If the body ends up being larger than this limit,
+  a `413` error code is returned.
+- `encoding` - The encoding to use to decode the body into a string.
+  By default, a `Buffer` instance will be returned when no encoding is specified.
+  Most likely, you want `utf-8`, so setting `encoding` to `true` will decode as `utf-8`.
+  You can use any type of encoding supported by [iconv-lite](https://www.npmjs.org/package/iconv-lite#readme).
+
+You can also pass a string in place of options to just specify the encoding.
+
+If an error occurs, the stream will be paused, everything unpiped,
+and you are responsible for correctly disposing the stream.
+For HTTP requests, you may need to finish consuming the stream if
+you want to keep the socket open for future requests. For streams
+that use file descriptors, you should `stream.destroy()` or
+`stream.close()` to prevent leaks.
+
+## Errors
+
+This module creates errors depending on the error condition during reading.
+The error may be an error from the underlying Node.js implementation, but is
+otherwise an error created by this module, which has the following attributes:
+
+  * `limit` - the limit in bytes
+  * `length` and `expected` - the expected length of the stream
+  * `received` - the received bytes
+  * `encoding` - the invalid encoding
+  * `status` and `statusCode` - the corresponding status code for the error
+  * `type` - the error type
+
+### Types
+
+The errors from this module have a `type` property which allows for the programmatic
+determination of the type of error returned.
+
+#### encoding.unsupported
+
+This error will occur when the `encoding` option is specified, but the value does
+not map to an encoding supported by the [iconv-lite](https://www.npmjs.org/package/iconv-lite#readme)
+module.
+
+#### entity.too.large
+
+This error will occur when the `limit` option is specified, but the stream has
+an entity that is larger.
+
+#### request.aborted
+
+This error will occur when the request stream is aborted by the client before
+reading the body has finished.
+
+#### request.size.invalid
+
+This error will occur when the `length` option is specified, but the stream has
+emitted more bytes.
+
+#### stream.encoding.set
+
+This error will occur when the given stream has an encoding set on it, making it
+a decoded stream. The stream should not have an encoding set and is expected to
+emit `Buffer` objects.
+
+#### stream.not.readable
+
+This error will occur when the given stream is not readable.
+
+## Examples
+
+### Simple Express example
+
+```js
+var contentType = require('content-type')
+var express = require('express')
+var getRawBody = require('raw-body')
+
+var app = express()
+
+app.use(function (req, res, next) {
+  getRawBody(req, {
+    length: req.headers['content-length'],
+    limit: '1mb',
+    encoding: contentType.parse(req).parameters.charset
+  }, function (err, string) {
+    if (err) return next(err)
+    req.text = string
+    next()
+  })
+})
+
+// now access req.text
+```
+
+### Simple Koa example
+
+```js
+var contentType = require('content-type')
+var getRawBody = require('raw-body')
+var koa = require('koa')
+
+var app = koa()
+
+app.use(function * (next) {
+  this.text = yield getRawBody(this.req, {
+    length: this.req.headers['content-length'],
+    limit: '1mb',
+    encoding: contentType.parse(this.req).parameters.charset
+  })
+  yield next
+})
+
+// now access this.text
+```
+
+### Using as a promise
+
+To use this library as a promise, simply omit the `callback` and a promise is
+returned, provided that a global `Promise` is defined.
+
+```js
+var getRawBody = require('raw-body')
+var http = require('http')
+
+var server = http.createServer(function (req, res) {
+  getRawBody(req)
+    .then(function (buf) {
+      res.statusCode = 200
+      res.end(buf.length + ' bytes submitted')
+    })
+    .catch(function (err) {
+      res.statusCode = 500
+      res.end(err.message)
+    })
+})
+
+server.listen(3000)
+```
+
+### Using with TypeScript
+
+```ts
+import * as getRawBody from 'raw-body';
+import * as http from 'http';
+
+const server = http.createServer((req, res) => {
+  getRawBody(req)
+  .then((buf) => {
+    res.statusCode = 200;
+    res.end(buf.length + ' bytes submitted');
+  })
+  .catch((err) => {
+    res.statusCode = err.statusCode;
+    res.end(err.message);
+  });
+});
+
+server.listen(3000);
+```
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/raw-body.svg
+[npm-url]: https://npmjs.org/package/raw-body
+[node-version-image]: https://img.shields.io/node/v/raw-body.svg
+[node-version-url]: https://nodejs.org/en/download/
+[coveralls-image]: https://img.shields.io/coveralls/stream-utils/raw-body/master.svg
+[coveralls-url]: https://coveralls.io/r/stream-utils/raw-body?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/raw-body.svg
+[downloads-url]: https://npmjs.org/package/raw-body
+[github-actions-ci-image]: https://img.shields.io/github/actions/workflow/status/stream-utils/raw-body/ci.yml?branch=master&label=ci
+[github-actions-ci-url]: https://github.com/jshttp/stream-utils/raw-body?query=workflow%3Aci
diff --git a/server/node_modules/raw-body/index.d.ts b/server/node_modules/raw-body/index.d.ts
new file mode 100644
index 0000000..dcbbebd
--- /dev/null
+++ b/server/node_modules/raw-body/index.d.ts
@@ -0,0 +1,87 @@
+import { Readable } from 'stream';
+
+declare namespace getRawBody {
+  export type Encoding = string | true;
+
+  export interface Options {
+    /**
+     * The expected length of the stream.
+     */
+    length?: number | string | null;
+    /**
+     * The byte limit of the body. This is the number of bytes or any string
+     * format supported by `bytes`, for example `1000`, `'500kb'` or `'3mb'`.
+     */
+    limit?: number | string | null;
+    /**
+     * The encoding to use to decode the body into a string. By default, a
+     * `Buffer` instance will be returned when no encoding is specified. Most
+     * likely, you want `utf-8`, so setting encoding to `true` will decode as
+     * `utf-8`. You can use any type of encoding supported by `iconv-lite`.
+     */
+    encoding?: Encoding | null;
+  }
+
+  export interface RawBodyError extends Error {
+    /**
+     * The limit in bytes.
+     */
+    limit?: number;
+    /**
+     * The expected length of the stream.
+     */
+    length?: number;
+    expected?: number;
+    /**
+     * The received bytes.
+     */
+    received?: number;
+    /**
+     * The encoding.
+     */
+    encoding?: string;
+    /**
+     * The corresponding status code for the error.
+     */
+    status: number;
+    statusCode: number;
+    /**
+     * The error type.
+     */
+    type: string;
+  }
+}
+
+/**
+ * Gets the entire buffer of a stream either as a `Buffer` or a string.
+ * Validates the stream's length against an expected length and maximum
+ * limit. Ideal for parsing request bodies.
+ */
+declare function getRawBody(
+  stream: Readable,
+  callback: (err: getRawBody.RawBodyError, body: Buffer) => void
+): void;
+
+declare function getRawBody(
+  stream: Readable,
+  options: (getRawBody.Options & { encoding: getRawBody.Encoding }) | getRawBody.Encoding,
+  callback: (err: getRawBody.RawBodyError, body: string) => void
+): void;
+
+declare function getRawBody(
+  stream: Readable,
+  options: getRawBody.Options,
+  callback: (err: getRawBody.RawBodyError, body: Buffer) => void
+): void;
+
+declare function getRawBody(
+  stream: Readable,
+  options: (getRawBody.Options & { encoding: getRawBody.Encoding }) | getRawBody.Encoding
+): Promise<string>;
+
+declare function getRawBody(
+  stream: Readable,
+  options?: getRawBody.Options
+): Promise<Buffer>;
+
+export = getRawBody;
diff --git a/server/node_modules/raw-body/index.js b/server/node_modules/raw-body/index.js
new file mode 100644
index 0000000..9cdcd12
--- /dev/null
+++ b/server/node_modules/raw-body/index.js
@@ -0,0 +1,336 @@
+/*!
+ * raw-body
+ * Copyright(c) 2013-2014 Jonathan Ong
+ * Copyright(c) 2014-2022 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var asyncHooks = tryRequireAsyncHooks()
+var bytes = require('bytes')
+var createError = require('http-errors')
+var iconv = require('iconv-lite')
+var unpipe = require('unpipe')
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = getRawBody
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var ICONV_ENCODING_MESSAGE_REGEXP = /^Encoding not recognized: /
+
+/**
+ * Get the decoder for a given encoding.
+ *
+ * @param {string} encoding
+ * @private
+ */
+
+function getDecoder (encoding) {
+  if (!encoding) return null
+
+  try {
+    return iconv.getDecoder(encoding)
+  } catch (e) {
+    // error getting decoder
+    if (!ICONV_ENCODING_MESSAGE_REGEXP.test(e.message)) throw e
+
+    // the encoding was not found
+    throw createError(415, 'specified encoding unsupported', {
+      encoding: encoding,
+      type: 'encoding.unsupported'
+    })
+  }
+}
+
+/**
+ * Get the raw body of a stream (typically HTTP).
+ *
+ * @param {object} stream
+ * @param {object|string|function} [options]
+ * @param {function} [callback]
+ * @public
+ */
+
+function getRawBody (stream, options, callback) {
+  var done = callback
+  var opts = options || {}
+
+  // light validation
+  if (stream === undefined) {
+    throw new TypeError('argument stream is required')
+  } else if (typeof stream !== 'object' || stream === null || typeof stream.on !== 'function') {
+    throw new TypeError('argument stream must be a stream')
+  }
+
+  if (options === true || typeof options === 'string') {
+    // short cut for encoding
+    opts = {
+      encoding: options
+    }
+  }
+
+  if (typeof options === 'function') {
+    done = options
+    opts = {}
+  }
+
+  // validate callback is a function, if provided
+  if (done !== undefined && typeof done !== 'function') {
+    throw new TypeError('argument callback must be a function')
+  }
+
+  // require the callback without promises
+  if (!done && !global.Promise) {
+    throw new TypeError('argument callback is required')
+  }
+
+  // get encoding
+  var encoding = opts.encoding !== true
+    ? opts.encoding
+    : 'utf-8'
+
+  // convert the limit to an integer
+  var limit = bytes.parse(opts.limit)
+
+  // convert the expected length to an integer
+  var length = opts.length != null && !isNaN(opts.length)
+    ? parseInt(opts.length, 10)
+    : null
+
+  if (done) {
+    // classic callback style
+    return readStream(stream, encoding, length, limit, wrap(done))
+  }
+
+  return new Promise(function executor (resolve, reject) {
+    readStream(stream, encoding, length, limit, function onRead (err, buf) {
+      if (err) return reject(err)
+      resolve(buf)
+    })
+  })
+}
+
+/**
+ * Halt a stream.
+ *
+ * @param {Object} stream
+ * @private
+ */
+
+function halt (stream) {
+  // unpipe everything from the stream
+  unpipe(stream)
+
+  // pause stream
+  if (typeof stream.pause === 'function') {
+    stream.pause()
+  }
+}
+
+/**
+ * Read the data from the stream.
+ *
+ * @param {object} stream
+ * @param {string} encoding
+ * @param {number} length
+ * @param {number} limit
+ * @param {function} callback
+ * @public
+ */
+
+function readStream (stream, encoding, length, limit, callback) {
+  var complete = false
+  var sync = true
+
+  // check the length and limit options.
+  // note: we intentionally leave the stream paused,
+  // so users should handle the stream themselves.
+  if (limit !== null && length !== null && length > limit) {
+    return done(createError(413, 'request entity too large', {
+      expected: length,
+      length: length,
+      limit: limit,
+      type: 'entity.too.large'
+    }))
+  }
+
+  // streams1: assert request encoding is buffer.
+  // streams2+: assert the stream encoding is buffer.
+  //   stream._decoder: streams1
+  //   state.encoding: streams2
+  //   state.decoder: streams2, specifically < 0.10.6
+  var state = stream._readableState
+  if (stream._decoder || (state && (state.encoding || state.decoder))) {
+    // developer error
+    return done(createError(500, 'stream encoding should not be set', {
+      type: 'stream.encoding.set'
+    }))
+  }
+
+  if (typeof stream.readable !== 'undefined' && !stream.readable) {
+    return done(createError(500, 'stream is not readable', {
+      type: 'stream.not.readable'
+    }))
+  }
+
+  var received = 0
+  var decoder
+
+  try {
+    decoder = getDecoder(encoding)
+  } catch (err) {
+    return done(err)
+  }
+
+  var buffer = decoder
+    ? ''
+    : []
+
+  // attach listeners
+  stream.on('aborted', onAborted)
+  stream.on('close', cleanup)
+  stream.on('data', onData)
+  stream.on('end', onEnd)
+  stream.on('error', onEnd)
+
+  // mark sync section complete
+  sync = false
+
+  function done () {
+    var args = new Array(arguments.length)
+
+    // copy arguments
+    for (var i = 0; i < args.length; i++) {
+      args[i] = arguments[i]
+    }
+
+    // mark complete
+    complete = true
+
+    if (sync) {
+      process.nextTick(invokeCallback)
+    } else {
+      invokeCallback()
+    }
+
+    function invokeCallback () {
+      cleanup()
+
+      if (args[0]) {
+        // halt the stream on error
+        halt(stream)
+      }
+
+      callback.apply(null, args)
+    }
+  }
+
+  function onAborted () {
+    if (complete) return
+
+    done(createError(400, 'request aborted', {
+      code: 'ECONNABORTED',
+      expected: length,
+      length: length,
+      received: received,
+      type: 'request.aborted'
+    }))
+  }
+
+  function onData (chunk) {
+    if (complete) return
+
+    received += chunk.length
+
+    if (limit !== null && received > limit) {
+      done(createError(413, 'request entity too large', {
+        limit: limit,
+        received: received,
+        type: 'entity.too.large'
+      }))
+    } else if (decoder) {
+      buffer += decoder.write(chunk)
+    } else {
+      buffer.push(chunk)
+    }
+  }
+
+  function onEnd (err) {
+    if (complete) return
+    if (err) return done(err)
+
+    if (length !== null && received !== length) {
+      done(createError(400, 'request size did not match content length', {
+        expected: length,
+        length: length,
+        received: received,
+        type: 'request.size.invalid'
+      }))
+    } else {
+      var string = decoder
+        ? buffer + (decoder.end() || '')
+        : Buffer.concat(buffer)
+      done(null, string)
+    }
+  }
+
+  function cleanup () {
+    buffer = null
+
+    stream.removeListener('aborted', onAborted)
+    stream.removeListener('data', onData)
+    stream.removeListener('end', onEnd)
+    stream.removeListener('error', onEnd)
+    stream.removeListener('close', cleanup)
+  }
+}
+
+/**
+ * Try to require async_hooks
+ * @private
+ */
+
+function tryRequireAsyncHooks () {
+  try {
+    return require('async_hooks')
+  } catch (e) {
+    return {}
+  }
+}
+
+/**
+ * Wrap function with async resource, if possible.
+ * AsyncResource.bind static method backported.
+ * @private
+ */
+
+function wrap (fn) {
+  var res
+
+  // create anonymous resource
+  if (asyncHooks.AsyncResource) {
+    res = new asyncHooks.AsyncResource(fn.name || 'bound-anonymous-fn')
+  }
+
+  // incompatible node.js
+  if (!res || !res.runInAsyncScope) {
+    return fn
+  }
+
+  // return bound function
+  return res.runInAsyncScope.bind(res, fn, null)
+}
diff --git a/server/node_modules/raw-body/package.json b/server/node_modules/raw-body/package.json
new file mode 100644
index 0000000..d8120af
--- /dev/null
+++ b/server/node_modules/raw-body/package.json
@@ -0,0 +1,47 @@
+{
+  "name": "raw-body",
+  "description": "Get and validate the raw body of a readable stream.",
+  "version": "2.5.3",
+  "author": "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Raynos <raynos2@gmail.com>"
+  ],
+  "license": "MIT",
+  "repository": "stream-utils/raw-body",
+  "dependencies": {
+    "bytes": "~3.1.2",
+    "http-errors": "~2.0.1",
+    "iconv-lite": "~0.4.24",
+    "unpipe": "~1.0.0"
+  },
+  "devDependencies": {
+    "bluebird": "3.7.2",
+    "eslint": "8.34.0",
+    "eslint-config-standard": "15.0.1",
+    "eslint-plugin-import": "2.27.5",
+    "eslint-plugin-markdown": "3.0.0",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "6.1.1",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "10.2.0",
+    "nyc": "15.1.0",
+    "readable-stream": "2.3.7",
+    "safe-buffer": "5.2.1"
+  },
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "files": [
+    "LICENSE",
+    "README.md",
+    "index.d.ts",
+    "index.js"
+  ],
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --trace-deprecation --reporter spec --bail --check-leaks test/",
+    "test-ci": "nyc --reporter=lcovonly --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/rc/LICENSE.APACHE2 b/server/node_modules/rc/LICENSE.APACHE2
new file mode 100644
index 0000000..6366c04
--- /dev/null
+++ b/server/node_modules/rc/LICENSE.APACHE2
@@ -0,0 +1,15 @@
+Apache License, Version 2.0
+
+Copyright (c) 2011 Dominic Tarr
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
diff --git a/server/node_modules/rc/LICENSE.BSD b/server/node_modules/rc/LICENSE.BSD
new file mode 100644
index 0000000..96bb796
--- /dev/null
+++ b/server/node_modules/rc/LICENSE.BSD
@@ -0,0 +1,26 @@
+Copyright (c) 2013, Dominic Tarr
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met: 
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer. 
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution. 
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+The views and conclusions contained in the software and documentation are those
+of the authors and should not be interpreted as representing official policies, 
+either expressed or implied, of the FreeBSD Project.
diff --git a/server/node_modules/rc/LICENSE.MIT b/server/node_modules/rc/LICENSE.MIT
new file mode 100644
index 0000000..6eafbd7
--- /dev/null
+++ b/server/node_modules/rc/LICENSE.MIT
@@ -0,0 +1,24 @@
+The MIT License
+
+Copyright (c) 2011 Dominic Tarr
+
+Permission is hereby granted, free of charge, 
+to any person obtaining a copy of this software and 
+associated documentation files (the "Software"), to 
+deal in the Software without restriction, including 
+without limitation the rights to use, copy, modify, 
+merge, publish, distribute, sublicense, and/or sell 
+copies of the Software, and to permit persons to whom 
+the Software is furnished to do so, 
+subject to the following conditions:
+
+The above copyright notice and this permission notice 
+shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR 
+ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/rc/README.md b/server/node_modules/rc/README.md
new file mode 100644
index 0000000..e6522e2
--- /dev/null
+++ b/server/node_modules/rc/README.md
@@ -0,0 +1,227 @@
+# rc
+
+The non-configurable configuration loader for lazy people.
+
+## Usage
+
+The only option is to pass rc the name of your app, and your default configuration.
+
+```javascript
+var conf = require('rc')(appname, {
+  //defaults go here.
+  port: 2468,
+
+  //defaults which are objects will be merged, not replaced
+  views: {
+    engine: 'jade'
+  }
+});
+```
+
+`rc` will return your configuration options merged with the defaults you specify.
+If you pass in a predefined defaults object, it will be mutated:
+
+```javascript
+var conf = {};
+require('rc')(appname, conf);
+```
+
+If `rc` finds any config files for your app, the returned config object will have
+a `configs` array containing their paths:
+
+```javascript
+var appCfg = require('rc')(appname, conf);
+appCfg.configs[0] // /etc/appnamerc
+appCfg.configs[1] // /home/dominictarr/.config/appname
+appCfg.config // same as appCfg.configs[appCfg.configs.length - 1]
+```
+
+## Standards
+
+Given your application name (`appname`), rc will look in all the obvious places for configuration.
+
+  * command line arguments, parsed by minimist _(e.g. `--foo baz`, also nested: `--foo.bar=baz`)_
+  * environment variables prefixed with `${appname}_`
+    * or use "\_\_" to indicate nested properties <br/> _(e.g. `appname_foo__bar__baz` => `foo.bar.baz`)_
+  * if you passed an option `--config file` then from that file
+  * a local `.${appname}rc` or the first found looking in `./ ../ ../../ ../../../` etc.
+  * `$HOME/.${appname}rc`
+  * `$HOME/.${appname}/config`
+  * `$HOME/.config/${appname}`
+  * `$HOME/.config/${appname}/config`
+  * `/etc/${appname}rc`
+  * `/etc/${appname}/config`
+  * the defaults object you passed in.
+
+All configuration sources that were found will be flattened into one object,
+so that sources **earlier** in this list override later ones.
+
+
+## Configuration File Formats
+
+Configuration files (e.g. `.appnamerc`) may be in either [json](http://json.org/example) or [ini](http://en.wikipedia.org/wiki/INI_file) format. **No** file extension (`.json` or `.ini`) should be used. The example configurations below are equivalent:
+
+
+#### Formatted as `ini`
+
+```
+; You can include comments in `ini` format if you want.
+
+dependsOn=0.10.0
+
+
+; `rc` has built-in support for ini sections, see?
+
+[commands]
+  www     = ./commands/www
+  console = ./commands/repl
+
+
+; You can even do nested sections
+
+[generators.options]
+  engine  = ejs
+
+[generators.modules]
+  new     = generate-new
+  engine  = generate-backend
+
+```
+
+#### Formatted as `json`
+
+```javascript
+{
+  // You can even comment your JSON, if you want
+  "dependsOn": "0.10.0",
+  "commands": {
+    "www": "./commands/www",
+    "console": "./commands/repl"
+  },
+  "generators": {
+    "options": {
+      "engine": "ejs"
+    },
+    "modules": {
+      "new": "generate-new",
+      "backend": "generate-backend"
+    }
+  }
+}
+```
+
+Comments are stripped from JSON config via [strip-json-comments](https://github.com/sindresorhus/strip-json-comments).
+
+> Since ini, and env variables do not have a standard for types, your application needs be prepared for strings.
+
+To ensure that string representations of booleans and numbers are always converted into their proper types (especially useful if you intend to do strict `===` comparisons), consider using a module such as [parse-strings-in-object](https://github.com/anselanza/parse-strings-in-object) to wrap the config object returned from rc.
+
+
+## Simple example demonstrating precedence
+Assume you have an application like this (notice the hard-coded defaults passed to rc):
+```
+const conf = require('rc')('myapp', {
+    port: 12345,
+    mode: 'test'
+});
+
+console.log(JSON.stringify(conf, null, 2));
+```
+You also have a file `config.json`, with these contents:
+```
+{
+  "port": 9000,
+  "foo": "from config json",
+  "something": "else"
+}
+```
+And a file `.myapprc` in the same folder, with these contents:
+```
+{
+  "port": "3001",
+  "foo": "bar"
+}
+```
+Here is the expected output from various commands:
+
+`node .`
+```
+{
+  "port": "3001",
+  "mode": "test",
+  "foo": "bar",
+  "_": [],
+  "configs": [
+    "/Users/stephen/repos/conftest/.myapprc"
+  ],
+  "config": "/Users/stephen/repos/conftest/.myapprc"
+}
+```
+*Default `mode` from hard-coded object is retained, but port is overridden by `.myapprc` file (automatically found based on appname match), and `foo` is added.*
+
+
+`node . --foo baz`
+```
+{
+  "port": "3001",
+  "mode": "test",
+  "foo": "baz",
+  "_": [],
+  "configs": [
+    "/Users/stephen/repos/conftest/.myapprc"
+  ],
+  "config": "/Users/stephen/repos/conftest/.myapprc"
+}
+```
+*Same result as above but `foo` is overridden because command-line arguments take precedence over `.myapprc` file.*
+
+`node . --foo barbar --config config.json`
+```
+{
+  "port": 9000,
+  "mode": "test",
+  "foo": "barbar",
+  "something": "else",
+  "_": [],
+  "config": "config.json",
+  "configs": [
+    "/Users/stephen/repos/conftest/.myapprc",
+    "config.json"
+  ]
+}
+```
+*Now the `port` comes from the `config.json` file specified (overriding the value from `.myapprc`), and `foo` value is overriden by command-line despite also being specified in the `config.json` file.*
+ 
+
+
+## Advanced Usage
+
+#### Pass in your own `argv`
+
+You may pass in your own `argv` as the third argument to `rc`.  This is in case you want to [use your own command-line opts parser](https://github.com/dominictarr/rc/pull/12).
+
+```javascript
+require('rc')(appname, defaults, customArgvParser);
+```
+
+## Pass in your own parser
+
+If you have a special need to use a non-standard parser,
+you can do so by passing in the parser as the 4th argument.
+(leave the 3rd as null to get the default args parser)
+
+```javascript
+require('rc')(appname, defaults, null, parser);
+```
+
+This may also be used to force a more strict format,
+such as strict, valid JSON only.
+
+## Note on Performance
+
+`rc` is running `fs.statSync`-- so make sure you don't use it in a hot code path (e.g. a request handler) 
+
+
+## License
+
+Multi-licensed under the two-clause BSD License, MIT License, or Apache License, version 2.0
diff --git a/server/node_modules/rc/browser.js b/server/node_modules/rc/browser.js
new file mode 100644
index 0000000..8c230c5
--- /dev/null
+++ b/server/node_modules/rc/browser.js
@@ -0,0 +1,7 @@
+
+// when this is loaded into the browser, 
+// just use the defaults...
+
+module.exports = function (name, defaults) {
+  return defaults
+}
diff --git a/server/node_modules/rc/cli.js b/server/node_modules/rc/cli.js
new file mode 100755
index 0000000..ab05b60
--- /dev/null
+++ b/server/node_modules/rc/cli.js
@@ -0,0 +1,4 @@
+#! /usr/bin/env node
+var rc = require('./index')
+
+console.log(JSON.stringify(rc(process.argv[2]), false, 2))
diff --git a/server/node_modules/rc/index.js b/server/node_modules/rc/index.js
new file mode 100755
index 0000000..65eb47a
--- /dev/null
+++ b/server/node_modules/rc/index.js
@@ -0,0 +1,53 @@
+var cc   = require('./lib/utils')
+var join = require('path').join
+var deepExtend = require('deep-extend')
+var etc = '/etc'
+var win = process.platform === "win32"
+var home = win
+           ? process.env.USERPROFILE
+           : process.env.HOME
+
+module.exports = function (name, defaults, argv, parse) {
+  if('string' !== typeof name)
+    throw new Error('rc(name): name *must* be string')
+  if(!argv)
+    argv = require('minimist')(process.argv.slice(2))
+  defaults = (
+      'string' === typeof defaults
+    ? cc.json(defaults) : defaults
+    ) || {}
+
+  parse = parse || cc.parse
+
+  var env = cc.env(name + '_')
+
+  var configs = [defaults]
+  var configFiles = []
+  function addConfigFile (file) {
+    if (configFiles.indexOf(file) >= 0) return
+    var fileConfig = cc.file(file)
+    if (fileConfig) {
+      configs.push(parse(fileConfig))
+      configFiles.push(file)
+    }
+  }
+
+  // which files do we look at?
+  if (!win)
+   [join(etc, name, 'config'),
+    join(etc, name + 'rc')].forEach(addConfigFile)
+  if (home)
+   [join(home, '.config', name, 'config'),
+    join(home, '.config', name),
+    join(home, '.' + name, 'config'),
+    join(home, '.' + name + 'rc')].forEach(addConfigFile)
+  addConfigFile(cc.find('.'+name+'rc'))
+  if (env.config) addConfigFile(env.config)
+  if (argv.config) addConfigFile(argv.config)
+
+  return deepExtend.apply(null, configs.concat([
+    env,
+    argv,
+    configFiles.length ? {configs: configFiles, config: configFiles[configFiles.length - 1]} : undefined,
+  ]))
+}
diff --git a/server/node_modules/rc/lib/utils.js b/server/node_modules/rc/lib/utils.js
new file mode 100644
index 0000000..8b3beff
--- /dev/null
+++ b/server/node_modules/rc/lib/utils.js
@@ -0,0 +1,104 @@
+'use strict';
+var fs   = require('fs')
+var ini  = require('ini')
+var path = require('path')
+var stripJsonComments = require('strip-json-comments')
+
+var parse = exports.parse = function (content) {
+
+  //if it ends in .json or starts with { then it must be json.
+  //must be done this way, because ini accepts everything.
+  //can't just try and parse it and let it throw if it's not ini.
+  //everything is ini. even json with a syntax error.
+
+  if(/^\s*{/.test(content))
+    return JSON.parse(stripJsonComments(content))
+  return ini.parse(content)
+
+}
+
+var file = exports.file = function () {
+  var args = [].slice.call(arguments).filter(function (arg) { return arg != null })
+
+  //path.join breaks if it's a not a string, so just skip this.
+  for(var i in args)
+    if('string' !== typeof args[i])
+      return
+
+  var file = path.join.apply(null, args)
+  var content
+  try {
+    return fs.readFileSync(file,'utf-8')
+  } catch (err) {
+    return
+  }
+}
+
+var json = exports.json = function () {
+  var content = file.apply(null, arguments)
+  return content ? parse(content) : null
+}
+
+var env = exports.env = function (prefix, env) {
+  env = env || process.env
+  var obj = {}
+  var l = prefix.length
+  for(var k in env) {
+    if(k.toLowerCase().indexOf(prefix.toLowerCase()) === 0) {
+
+      var keypath = k.substring(l).split('__')
+
+      // Trim empty strings from keypath array
+      var _emptyStringIndex
+      while ((_emptyStringIndex=keypath.indexOf('')) > -1) {
+        keypath.splice(_emptyStringIndex, 1)
+      }
+
+      var cursor = obj
+      keypath.forEach(function _buildSubObj(_subkey,i){
+
+        // (check for _subkey first so we ignore empty strings)
+        // (check for cursor to avoid assignment to primitive objects)
+        if (!_subkey || typeof cursor !== 'object')
+          return
+
+        // If this is the last key, just stuff the value in there
+        // Assigns actual value from env variable to final key
+        // (unless it's just an empty string- in that case use the last valid key)
+        if (i === keypath.length-1)
+          cursor[_subkey] = env[k]
+
+
+        // Build sub-object if nothing already exists at the keypath
+        if (cursor[_subkey] === undefined)
+          cursor[_subkey] = {}
+
+        // Increment cursor used to track the object at the current depth
+        cursor = cursor[_subkey]
+
+      })
+
+    }
+
+  }
+
+  return obj
+}
+
+var find = exports.find = function () {
+  var rel = path.join.apply(null, [].slice.call(arguments))
+
+  function find(start, rel) {
+    var file = path.join(start, rel)
+    try {
+      fs.statSync(file)
+      return file
+    } catch (err) {
+      if(path.dirname(start) !== start) // root
+        return find(path.dirname(start), rel)
+    }
+  }
+  return find(process.cwd(), rel)
+}
+
+
diff --git a/server/node_modules/rc/package.json b/server/node_modules/rc/package.json
new file mode 100644
index 0000000..887238f
--- /dev/null
+++ b/server/node_modules/rc/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "rc",
+  "version": "1.2.8",
+  "description": "hardwired configuration loader",
+  "main": "index.js",
+  "browser": "browser.js",
+  "scripts": {
+    "test": "set -e; node test/test.js; node test/ini.js; node test/nested-env-vars.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/dominictarr/rc.git"
+  },
+  "license": "(BSD-2-Clause OR MIT OR Apache-2.0)",
+  "keywords": [
+    "config",
+    "rc",
+    "unix",
+    "defaults"
+  ],
+  "bin": "./cli.js",
+  "author": "Dominic Tarr <dominic.tarr@gmail.com> (dominictarr.com)",
+  "dependencies": {
+    "deep-extend": "^0.6.0",
+    "ini": "~1.3.0",
+    "minimist": "^1.2.0",
+    "strip-json-comments": "~2.0.1"
+  }
+}
diff --git a/server/node_modules/rc/test/ini.js b/server/node_modules/rc/test/ini.js
new file mode 100644
index 0000000..e6857f8
--- /dev/null
+++ b/server/node_modules/rc/test/ini.js
@@ -0,0 +1,16 @@
+var cc =require('../lib/utils')
+var INI = require('ini')
+var assert = require('assert')
+
+function test(obj) {
+
+  var _json, _ini
+  var json = cc.parse (_json = JSON.stringify(obj))
+  var ini = cc.parse (_ini = INI.stringify(obj))
+  console.log(_ini, _json)
+  assert.deepEqual(json, ini)
+}
+
+
+test({hello: true})
+
diff --git a/server/node_modules/rc/test/nested-env-vars.js b/server/node_modules/rc/test/nested-env-vars.js
new file mode 100644
index 0000000..0ecd176
--- /dev/null
+++ b/server/node_modules/rc/test/nested-env-vars.js
@@ -0,0 +1,50 @@
+
+var seed = Math.random();
+var n = 'rc'+ seed;
+var N = 'RC'+ seed;
+var assert = require('assert')
+
+
+// Basic usage
+process.env[n+'_someOpt__a'] = 42
+process.env[n+'_someOpt__x__'] = 99
+process.env[n+'_someOpt__a__b'] = 186
+process.env[n+'_someOpt__a__b__c'] = 243
+process.env[n+'_someOpt__x__y'] = 1862
+process.env[n+'_someOpt__z'] = 186577
+
+// Should ignore empty strings from orphaned '__'
+process.env[n+'_someOpt__z__x__'] = 18629
+process.env[n+'_someOpt__w__w__'] = 18629
+
+// Leading '__' should ignore everything up to 'z'
+process.env[n+'___z__i__'] = 9999
+
+// should ignore case for config name section.
+process.env[N+'_test_upperCase'] = 187
+
+function testPrefix(prefix) {
+	var config = require('../')(prefix, {
+	  option: true
+	})
+
+	console.log('\n\n------ nested-env-vars ------\n',{prefix: prefix}, '\n', config);
+
+	assert.equal(config.option, true)
+	assert.equal(config.someOpt.a, 42)
+	assert.equal(config.someOpt.x, 99)
+	// Should not override `a` once it's been set
+	assert.equal(config.someOpt.a/*.b*/, 42)
+	// Should not override `x` once it's been set
+	assert.equal(config.someOpt.x/*.y*/, 99)
+	assert.equal(config.someOpt.z, 186577)
+	// Should not override `z` once it's been set
+	assert.equal(config.someOpt.z/*.x*/, 186577)
+	assert.equal(config.someOpt.w.w, 18629)
+	assert.equal(config.z.i, 9999)
+
+	assert.equal(config.test_upperCase, 187)
+}
+
+testPrefix(n);
+testPrefix(N);
diff --git a/server/node_modules/rc/test/test.js b/server/node_modules/rc/test/test.js
new file mode 100644
index 0000000..4f63351
--- /dev/null
+++ b/server/node_modules/rc/test/test.js
@@ -0,0 +1,59 @@
+
+var n = 'rc'+Math.random()
+var assert = require('assert')
+
+process.env[n+'_envOption'] = 42
+
+var config = require('../')(n, {
+  option: true
+})
+
+console.log(config)
+
+assert.equal(config.option, true)
+assert.equal(config.envOption, 42)
+
+var customArgv = require('../')(n, {
+  option: true
+}, { // nopt-like argv
+  option: false,
+  envOption: 24,
+  argv: {
+    remain: [],
+    cooked: ['--no-option', '--envOption', '24'],
+    original: ['--no-option', '--envOption=24']
+  }
+})
+
+console.log(customArgv)
+
+assert.equal(customArgv.option, false)
+assert.equal(customArgv.envOption, 24)
+
+var fs = require('fs')
+var path = require('path')
+var jsonrc = path.resolve('.' + n + 'rc');
+
+fs.writeFileSync(jsonrc, [
+  '{',
+    '// json overrides default',
+    '"option": false,',
+    '/* env overrides json */',
+    '"envOption": 24',
+  '}'
+].join('\n'));
+
+var commentedJSON = require('../')(n, {
+  option: true
+})
+
+fs.unlinkSync(jsonrc);
+
+console.log(commentedJSON)
+
+assert.equal(commentedJSON.option, false)
+assert.equal(commentedJSON.envOption, 42)
+
+assert.equal(commentedJSON.config, jsonrc)
+assert.equal(commentedJSON.configs.length, 1)
+assert.equal(commentedJSON.configs[0], jsonrc)
diff --git a/server/node_modules/readable-stream/.travis.yml b/server/node_modules/readable-stream/.travis.yml
new file mode 100644
index 0000000..f62cdac
--- /dev/null
+++ b/server/node_modules/readable-stream/.travis.yml
@@ -0,0 +1,34 @@
+sudo: false
+language: node_js
+before_install:
+  - (test $NPM_LEGACY && npm install -g npm@2 && npm install -g npm@3) || true
+notifications:
+  email: false
+matrix:
+  fast_finish: true
+  include:
+  - node_js: '0.8'
+    env: NPM_LEGACY=true
+  - node_js: '0.10'
+    env: NPM_LEGACY=true
+  - node_js: '0.11'
+    env: NPM_LEGACY=true
+  - node_js: '0.12'
+    env: NPM_LEGACY=true
+  - node_js: 1
+    env: NPM_LEGACY=true
+  - node_js: 2
+    env: NPM_LEGACY=true
+  - node_js: 3
+    env: NPM_LEGACY=true
+  - node_js: 4
+  - node_js: 5
+  - node_js: 6
+  - node_js: 7
+  - node_js: 8
+  - node_js: 9
+script: "npm run test"
+env:
+  global:
+  - secure: rE2Vvo7vnjabYNULNyLFxOyt98BoJexDqsiOnfiD6kLYYsiQGfr/sbZkPMOFm9qfQG7pjqx+zZWZjGSswhTt+626C0t/njXqug7Yps4c3dFblzGfreQHp7wNX5TFsvrxd6dAowVasMp61sJcRnB2w8cUzoe3RAYUDHyiHktwqMc=
+  - secure: g9YINaKAdMatsJ28G9jCGbSaguXCyxSTy+pBO6Ch0Cf57ZLOTka3HqDj8p3nV28LUIHZ3ut5WO43CeYKwt4AUtLpBS3a0dndHdY6D83uY6b2qh5hXlrcbeQTq2cvw2y95F7hm4D1kwrgZ7ViqaKggRcEupAL69YbJnxeUDKWEdI=
diff --git a/server/node_modules/readable-stream/CONTRIBUTING.md b/server/node_modules/readable-stream/CONTRIBUTING.md
new file mode 100644
index 0000000..f478d58
--- /dev/null
+++ b/server/node_modules/readable-stream/CONTRIBUTING.md
@@ -0,0 +1,38 @@
+# Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+* (a) The contribution was created in whole or in part by me and I
+  have the right to submit it under the open source license
+  indicated in the file; or
+
+* (b) The contribution is based upon previous work that, to the best
+  of my knowledge, is covered under an appropriate open source
+  license and I have the right under that license to submit that
+  work with modifications, whether created in whole or in part
+  by me, under the same open source license (unless I am
+  permitted to submit under a different license), as indicated
+  in the file; or
+
+* (c) The contribution was provided directly to me by some other
+  person who certified (a), (b) or (c) and I have not modified
+  it.
+
+* (d) I understand and agree that this project and the contribution
+  are public and that a record of the contribution (including all
+  personal information I submit with it, including my sign-off) is
+  maintained indefinitely and may be redistributed consistent with
+  this project or the open source license(s) involved.
+
+## Moderation Policy
+
+The [Node.js Moderation Policy] applies to this WG.
+
+## Code of Conduct
+
+The [Node.js Code of Conduct][] applies to this WG.
+
+[Node.js Code of Conduct]:
+https://github.com/nodejs/node/blob/master/CODE_OF_CONDUCT.md
+[Node.js Moderation Policy]:
+https://github.com/nodejs/TSC/blob/master/Moderation-Policy.md
diff --git a/server/node_modules/readable-stream/GOVERNANCE.md b/server/node_modules/readable-stream/GOVERNANCE.md
new file mode 100644
index 0000000..16ffb93
--- /dev/null
+++ b/server/node_modules/readable-stream/GOVERNANCE.md
@@ -0,0 +1,136 @@
+### Streams Working Group
+
+The Node.js Streams is jointly governed by a Working Group
+(WG)
+that is responsible for high-level guidance of the project.
+
+The WG has final authority over this project including:
+
+* Technical direction
+* Project governance and process (including this policy)
+* Contribution policy
+* GitHub repository hosting
+* Conduct guidelines
+* Maintaining the list of additional Collaborators
+
+For the current list of WG members, see the project
+[README.md](./README.md#current-project-team-members).
+
+### Collaborators
+
+The readable-stream GitHub repository is
+maintained by the WG and additional Collaborators who are added by the
+WG on an ongoing basis.
+
+Individuals making significant and valuable contributions are made
+Collaborators and given commit-access to the project. These
+individuals are identified by the WG and their addition as
+Collaborators is discussed during the WG meeting.
+
+_Note:_ If you make a significant contribution and are not considered
+for commit-access log an issue or contact a WG member directly and it
+will be brought up in the next WG meeting.
+
+Modifications of the contents of the readable-stream repository are
+made on
+a collaborative basis. Anybody with a GitHub account may propose a
+modification via pull request and it will be considered by the project
+Collaborators. All pull requests must be reviewed and accepted by a
+Collaborator with sufficient expertise who is able to take full
+responsibility for the change. In the case of pull requests proposed
+by an existing Collaborator, an additional Collaborator is required
+for sign-off. Consensus should be sought if additional Collaborators
+participate and there is disagreement around a particular
+modification. See _Consensus Seeking Process_ below for further detail
+on the consensus model used for governance.
+
+Collaborators may opt to elevate significant or controversial
+modifications, or modifications that have not found consensus to the
+WG for discussion by assigning the ***WG-agenda*** tag to a pull
+request or issue. The WG should serve as the final arbiter where
+required.
+
+For the current list of Collaborators, see the project
+[README.md](./README.md#members).
+
+### WG Membership
+
+WG seats are not time-limited.  There is no fixed size of the WG.
+However, the expected target is between 6 and 12, to ensure adequate
+coverage of important areas of expertise, balanced with the ability to
+make decisions efficiently.
+
+There is no specific set of requirements or qualifications for WG
+membership beyond these rules.
+
+The WG may add additional members to the WG by unanimous consensus.
+
+A WG member may be removed from the WG by voluntary resignation, or by
+unanimous consensus of all other WG members.
+
+Changes to WG membership should be posted in the agenda, and may be
+suggested as any other agenda item (see "WG Meetings" below).
+
+If an addition or removal is proposed during a meeting, and the full
+WG is not in attendance to participate, then the addition or removal
+is added to the agenda for the subsequent meeting.  This is to ensure
+that all members are given the opportunity to participate in all
+membership decisions.  If a WG member is unable to attend a meeting
+where a planned membership decision is being made, then their consent
+is assumed.
+
+No more than 1/3 of the WG members may be affiliated with the same
+employer.  If removal or resignation of a WG member, or a change of
+employment by a WG member, creates a situation where more than 1/3 of
+the WG membership shares an employer, then the situation must be
+immediately remedied by the resignation or removal of one or more WG
+members affiliated with the over-represented employer(s).
+
+### WG Meetings
+
+The WG meets occasionally on a Google Hangout On Air. A designated moderator
+approved by the WG runs the meeting. Each meeting should be
+published to YouTube.
+
+Items are added to the WG agenda that are considered contentious or
+are modifications of governance, contribution policy, WG membership,
+or release process.
+
+The intention of the agenda is not to approve or review all patches;
+that should happen continuously on GitHub and be handled by the larger
+group of Collaborators.
+
+Any community member or contributor can ask that something be added to
+the next meeting's agenda by logging a GitHub Issue. Any Collaborator,
+WG member or the moderator can add the item to the agenda by adding
+the ***WG-agenda*** tag to the issue.
+
+Prior to each WG meeting the moderator will share the Agenda with
+members of the WG. WG members can add any items they like to the
+agenda at the beginning of each meeting. The moderator and the WG
+cannot veto or remove items.
+
+The WG may invite persons or representatives from certain projects to
+participate in a non-voting capacity.
+
+The moderator is responsible for summarizing the discussion of each
+agenda item and sends it as a pull request after the meeting.
+
+### Consensus Seeking Process
+
+The WG follows a
+[Consensus
+Seeking](http://en.wikipedia.org/wiki/Consensus-seeking_decision-making)
+decision-making model.
+
+When an agenda item has appeared to reach a consensus the moderator
+will ask "Does anyone object?" as a final call for dissent from the
+consensus.
+
+If an agenda item cannot reach a consensus a WG member can call for
+either a closing vote or a vote to table the issue to the next
+meeting. The call for a vote must be seconded by a majority of the WG
+or else the discussion will continue. Simple majority wins.
+
+Note that changes to WG membership require a majority consensus.  See
+"WG Membership" above.
diff --git a/server/node_modules/readable-stream/LICENSE b/server/node_modules/readable-stream/LICENSE
new file mode 100644
index 0000000..2873b3b
--- /dev/null
+++ b/server/node_modules/readable-stream/LICENSE
@@ -0,0 +1,47 @@
+Node.js is licensed for use as follows:
+
+"""
+Copyright Node.js contributors. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
+
+This license applies to parts of Node.js originating from the
+https://github.com/joyent/node repository:
+
+"""
+Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
diff --git a/server/node_modules/readable-stream/README.md b/server/node_modules/readable-stream/README.md
new file mode 100644
index 0000000..f1c5a93
--- /dev/null
+++ b/server/node_modules/readable-stream/README.md
@@ -0,0 +1,58 @@
+# readable-stream
+
+***Node-core v8.17.0 streams for userland*** [![Build Status](https://travis-ci.org/nodejs/readable-stream.svg?branch=master)](https://travis-ci.org/nodejs/readable-stream)
+
+
+[![NPM](https://nodei.co/npm/readable-stream.png?downloads=true&downloadRank=true)](https://nodei.co/npm/readable-stream/)
+[![NPM](https://nodei.co/npm-dl/readable-stream.png?&months=6&height=3)](https://nodei.co/npm/readable-stream/)
+
+
+[![Sauce Test Status](https://saucelabs.com/browser-matrix/readable-stream.svg)](https://saucelabs.com/u/readable-stream)
+
+```bash
+npm install --save readable-stream
+```
+
+***Node-core streams for userland***
+
+This package is a mirror of the Streams2 and Streams3 implementations in
+Node-core.
+
+Full documentation may be found on the [Node.js website](https://nodejs.org/dist/v8.17.0/docs/api/stream.html).
+
+If you want to guarantee a stable streams base, regardless of what version of
+Node you, or the users of your libraries are using, use **readable-stream** *only* and avoid the *"stream"* module in Node-core, for background see [this blogpost](http://r.va.gg/2014/06/why-i-dont-use-nodes-core-stream-module.html).
+
+As of version 2.0.0 **readable-stream** uses semantic versioning.
+
+# Streams Working Group
+
+`readable-stream` is maintained by the Streams Working Group, which
+oversees the development and maintenance of the Streams API within
+Node.js. The responsibilities of the Streams Working Group include:
+
+* Addressing stream issues on the Node.js issue tracker.
+* Authoring and editing stream documentation within the Node.js project.
+* Reviewing changes to stream subclasses within the Node.js project.
+* Redirecting changes to streams from the Node.js project to this
+  project.
+* Assisting in the implementation of stream providers within Node.js.
+* Recommending versions of `readable-stream` to be included in Node.js.
+* Messaging about the future of streams to give the community advance
+  notice of changes.
+
+<a name="members"></a>
+## Team Members
+
+* **Chris Dickinson** ([@chrisdickinson](https://github.com/chrisdickinson)) <christopher.s.dickinson@gmail.com>
+  - Release GPG key: 9554F04D7259F04124DE6B476D5A82AC7E37093B
+* **Calvin Metcalf** ([@calvinmetcalf](https://github.com/calvinmetcalf)) <calvin.metcalf@gmail.com>
+  - Release GPG key: F3EF5F62A87FC27A22E643F714CE4FF5015AA242
+* **Rod Vagg** ([@rvagg](https://github.com/rvagg)) <rod@vagg.org>
+  - Release GPG key: DD8F2338BAE7501E3DD5AC78C273792F7D83545D
+* **Sam Newman** ([@sonewman](https://github.com/sonewman)) <newmansam@outlook.com>
+* **Mathias Buus** ([@mafintosh](https://github.com/mafintosh)) <mathiasbuus@gmail.com>
+* **Domenic Denicola** ([@domenic](https://github.com/domenic)) <d@domenic.me>
+* **Matteo Collina** ([@mcollina](https://github.com/mcollina)) <matteo.collina@gmail.com>
+  - Release GPG key: 3ABC01543F22DD2239285CDD818674489FBC127E
+* **Irina Shestak** ([@lrlna](https://github.com/lrlna)) <shestak.irina@gmail.com>
diff --git a/server/node_modules/readable-stream/doc/wg-meetings/2015-01-30.md b/server/node_modules/readable-stream/doc/wg-meetings/2015-01-30.md
new file mode 100644
index 0000000..83275f1
--- /dev/null
+++ b/server/node_modules/readable-stream/doc/wg-meetings/2015-01-30.md
@@ -0,0 +1,60 @@
+# streams WG Meeting 2015-01-30
+
+## Links
+
+* **Google Hangouts Video**: http://www.youtube.com/watch?v=I9nDOSGfwZg
+* **GitHub Issue**: https://github.com/iojs/readable-stream/issues/106
+* **Original Minutes Google Doc**: https://docs.google.com/document/d/17aTgLnjMXIrfjgNaTUnHQO7m3xgzHR2VXBTmi03Qii4/
+
+## Agenda
+
+Extracted from https://github.com/iojs/readable-stream/labels/wg-agenda prior to meeting.
+
+* adopt a charter [#105](https://github.com/iojs/readable-stream/issues/105)
+* release and versioning strategy [#101](https://github.com/iojs/readable-stream/issues/101)
+* simpler stream creation [#102](https://github.com/iojs/readable-stream/issues/102)
+* proposal: deprecate implicit flowing of streams [#99](https://github.com/iojs/readable-stream/issues/99)
+
+## Minutes
+
+### adopt a charter
+
+* group: +1's all around
+
+### What versioning scheme should be adopted?
+* group: +1’s 3.0.0
+* domenic+group: pulling in patches from other sources where appropriate
+* mikeal: version independently, suggesting versions for io.js
+* mikeal+domenic: work with TC to notify in advance of changes
+simpler stream creation
+
+### streamline creation of streams
+* sam: streamline creation of streams
+* domenic: nice simple solution posted
+  but, we lose the opportunity to change the model
+  may not be backwards incompatible (double check keys)
+
+  **action item:** domenic will check
+
+### remove implicit flowing of streams on(‘data’)
+* add isFlowing / isPaused
+* mikeal: worrying that we’re documenting polyfill methods – confuses users
+* domenic: more reflective API is probably good, with warning labels for users
+* new section for mad scientists (reflective stream access)
+* calvin: name the “third state”
+* mikeal: maybe borrow the name from whatwg?
+* domenic: we’re missing the “third state”
+* consensus: kind of difficult to name the third state
+* mikeal: figure out differences in states / compat
+* mathias: always flow on data – eliminates third state
+  * explore what it breaks
+
+**action items:**
+* ask isaac for ability to list packages by what public io.js APIs they use (esp. Stream)
+* ask rod/build for infrastructure
+* **chris**: explore the “flow on data” approach
+* add isPaused/isFlowing
+* add new docs section
+* move isPaused to that section
+
+
diff --git a/server/node_modules/readable-stream/duplex-browser.js b/server/node_modules/readable-stream/duplex-browser.js
new file mode 100644
index 0000000..f8b2db8
--- /dev/null
+++ b/server/node_modules/readable-stream/duplex-browser.js
@@ -0,0 +1 @@
+module.exports = require('./lib/_stream_duplex.js');
diff --git a/server/node_modules/readable-stream/duplex.js b/server/node_modules/readable-stream/duplex.js
new file mode 100644
index 0000000..46924cb
--- /dev/null
+++ b/server/node_modules/readable-stream/duplex.js
@@ -0,0 +1 @@
+module.exports = require('./readable').Duplex
diff --git a/server/node_modules/readable-stream/lib/_stream_duplex.js b/server/node_modules/readable-stream/lib/_stream_duplex.js
new file mode 100644
index 0000000..57003c3
--- /dev/null
+++ b/server/node_modules/readable-stream/lib/_stream_duplex.js
@@ -0,0 +1,131 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a duplex stream is just a stream that is both readable and writable.
+// Since JS doesn't have multiple prototypal inheritance, this class
+// prototypally inherits from Readable, and then parasitically from
+// Writable.
+
+'use strict';
+
+/*<replacement>*/
+
+var pna = require('process-nextick-args');
+/*</replacement>*/
+
+/*<replacement>*/
+var objectKeys = Object.keys || function (obj) {
+  var keys = [];
+  for (var key in obj) {
+    keys.push(key);
+  }return keys;
+};
+/*</replacement>*/
+
+module.exports = Duplex;
+
+/*<replacement>*/
+var util = Object.create(require('core-util-is'));
+util.inherits = require('inherits');
+/*</replacement>*/
+
+var Readable = require('./_stream_readable');
+var Writable = require('./_stream_writable');
+
+util.inherits(Duplex, Readable);
+
+{
+  // avoid scope creep, the keys array can then be collected
+  var keys = objectKeys(Writable.prototype);
+  for (var v = 0; v < keys.length; v++) {
+    var method = keys[v];
+    if (!Duplex.prototype[method]) Duplex.prototype[method] = Writable.prototype[method];
+  }
+}
+
+function Duplex(options) {
+  if (!(this instanceof Duplex)) return new Duplex(options);
+
+  Readable.call(this, options);
+  Writable.call(this, options);
+
+  if (options && options.readable === false) this.readable = false;
+
+  if (options && options.writable === false) this.writable = false;
+
+  this.allowHalfOpen = true;
+  if (options && options.allowHalfOpen === false) this.allowHalfOpen = false;
+
+  this.once('end', onend);
+}
+
+Object.defineProperty(Duplex.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function () {
+    return this._writableState.highWaterMark;
+  }
+});
+
+// the no-half-open enforcer
+function onend() {
+  // if we allow half-open state, or if the writable side ended,
+  // then we're ok.
+  if (this.allowHalfOpen || this._writableState.ended) return;
+
+  // no more data can be written.
+  // But allow more writes to happen in this tick.
+  pna.nextTick(onEndNT, this);
+}
+
+function onEndNT(self) {
+  self.end();
+}
+
+Object.defineProperty(Duplex.prototype, 'destroyed', {
+  get: function () {
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed && this._writableState.destroyed;
+  },
+  set: function (value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+    this._writableState.destroyed = value;
+  }
+});
+
+Duplex.prototype._destroy = function (err, cb) {
+  this.push(null);
+  this.end();
+
+  pna.nextTick(cb, err);
+};
\ No newline at end of file
diff --git a/server/node_modules/readable-stream/lib/_stream_passthrough.js b/server/node_modules/readable-stream/lib/_stream_passthrough.js
new file mode 100644
index 0000000..612edb4
--- /dev/null
+++ b/server/node_modules/readable-stream/lib/_stream_passthrough.js
@@ -0,0 +1,47 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a passthrough stream.
+// basically just the most minimal sort of Transform stream.
+// Every written chunk gets output as-is.
+
+'use strict';
+
+module.exports = PassThrough;
+
+var Transform = require('./_stream_transform');
+
+/*<replacement>*/
+var util = Object.create(require('core-util-is'));
+util.inherits = require('inherits');
+/*</replacement>*/
+
+util.inherits(PassThrough, Transform);
+
+function PassThrough(options) {
+  if (!(this instanceof PassThrough)) return new PassThrough(options);
+
+  Transform.call(this, options);
+}
+
+PassThrough.prototype._transform = function (chunk, encoding, cb) {
+  cb(null, chunk);
+};
\ No newline at end of file
diff --git a/server/node_modules/readable-stream/lib/_stream_readable.js b/server/node_modules/readable-stream/lib/_stream_readable.js
new file mode 100644
index 0000000..3af95cb
--- /dev/null
+++ b/server/node_modules/readable-stream/lib/_stream_readable.js
@@ -0,0 +1,1019 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+
+/*<replacement>*/
+
+var pna = require('process-nextick-args');
+/*</replacement>*/
+
+module.exports = Readable;
+
+/*<replacement>*/
+var isArray = require('isarray');
+/*</replacement>*/
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Readable.ReadableState = ReadableState;
+
+/*<replacement>*/
+var EE = require('events').EventEmitter;
+
+var EElistenerCount = function (emitter, type) {
+  return emitter.listeners(type).length;
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+/*<replacement>*/
+
+var Buffer = require('safe-buffer').Buffer;
+var OurUint8Array = (typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : typeof self !== 'undefined' ? self : {}).Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+
+/*</replacement>*/
+
+/*<replacement>*/
+var util = Object.create(require('core-util-is'));
+util.inherits = require('inherits');
+/*</replacement>*/
+
+/*<replacement>*/
+var debugUtil = require('util');
+var debug = void 0;
+if (debugUtil && debugUtil.debuglog) {
+  debug = debugUtil.debuglog('stream');
+} else {
+  debug = function () {};
+}
+/*</replacement>*/
+
+var BufferList = require('./internal/streams/BufferList');
+var destroyImpl = require('./internal/streams/destroy');
+var StringDecoder;
+
+util.inherits(Readable, Stream);
+
+var kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
+
+function prependListener(emitter, event, fn) {
+  // Sadly this is not cacheable as some libraries bundle their own
+  // event emitter implementation with them.
+  if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn);
+
+  // This is a hack to make sure that our error handler is attached before any
+  // userland ones.  NEVER DO THIS. This is here only because this code needs
+  // to continue to work with older versions of Node.js that do not include
+  // the prependListener() method. The goal is to eventually remove this hack.
+  if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
+}
+
+function ReadableState(options, stream) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream.
+  // These options can be provided separately as readableXXX and writableXXX.
+  var isDuplex = stream instanceof Duplex;
+
+  // object stream flag. Used to make read(n) ignore n and to
+  // make all the buffer merging and length checks go away
+  this.objectMode = !!options.objectMode;
+
+  if (isDuplex) this.objectMode = this.objectMode || !!options.readableObjectMode;
+
+  // the point at which it stops calling _read() to fill the buffer
+  // Note: 0 is a valid value, means "don't call _read preemptively ever"
+  var hwm = options.highWaterMark;
+  var readableHwm = options.readableHighWaterMark;
+  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
+
+  if (hwm || hwm === 0) this.highWaterMark = hwm;else if (isDuplex && (readableHwm || readableHwm === 0)) this.highWaterMark = readableHwm;else this.highWaterMark = defaultHwm;
+
+  // cast to ints.
+  this.highWaterMark = Math.floor(this.highWaterMark);
+
+  // A linked list is used to store data chunks instead of an array because the
+  // linked list can remove elements from the beginning faster than
+  // array.shift()
+  this.buffer = new BufferList();
+  this.length = 0;
+  this.pipes = null;
+  this.pipesCount = 0;
+  this.flowing = null;
+  this.ended = false;
+  this.endEmitted = false;
+  this.reading = false;
+
+  // a flag to be able to tell if the event 'readable'/'data' is emitted
+  // immediately, or on a later tick.  We set this to true at first, because
+  // any actions that shouldn't happen until "later" should generally also
+  // not happen before the first read call.
+  this.sync = true;
+
+  // whenever we return null, then we set a flag to say
+  // that we're awaiting a 'readable' event emission.
+  this.needReadable = false;
+  this.emittedReadable = false;
+  this.readableListening = false;
+  this.resumeScheduled = false;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // the number of writers that are awaiting a drain event in .pipe()s
+  this.awaitDrain = 0;
+
+  // if true, a maybeReadMore has been scheduled
+  this.readingMore = false;
+
+  this.decoder = null;
+  this.encoding = null;
+  if (options.encoding) {
+    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+    this.decoder = new StringDecoder(options.encoding);
+    this.encoding = options.encoding;
+  }
+}
+
+function Readable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  if (!(this instanceof Readable)) return new Readable(options);
+
+  this._readableState = new ReadableState(options, this);
+
+  // legacy
+  this.readable = true;
+
+  if (options) {
+    if (typeof options.read === 'function') this._read = options.read;
+
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+  }
+
+  Stream.call(this);
+}
+
+Object.defineProperty(Readable.prototype, 'destroyed', {
+  get: function () {
+    if (this._readableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed;
+  },
+  set: function (value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._readableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+  }
+});
+
+Readable.prototype.destroy = destroyImpl.destroy;
+Readable.prototype._undestroy = destroyImpl.undestroy;
+Readable.prototype._destroy = function (err, cb) {
+  this.push(null);
+  cb(err);
+};
+
+// Manually shove something into the read() buffer.
+// This returns true if the highWaterMark has not been hit yet,
+// similar to how Writable.write() returns true if you should
+// write() some more.
+Readable.prototype.push = function (chunk, encoding) {
+  var state = this._readableState;
+  var skipChunkCheck;
+
+  if (!state.objectMode) {
+    if (typeof chunk === 'string') {
+      encoding = encoding || state.defaultEncoding;
+      if (encoding !== state.encoding) {
+        chunk = Buffer.from(chunk, encoding);
+        encoding = '';
+      }
+      skipChunkCheck = true;
+    }
+  } else {
+    skipChunkCheck = true;
+  }
+
+  return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
+};
+
+// Unshift should *always* be something directly out of read()
+Readable.prototype.unshift = function (chunk) {
+  return readableAddChunk(this, chunk, null, true, false);
+};
+
+function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
+  var state = stream._readableState;
+  if (chunk === null) {
+    state.reading = false;
+    onEofChunk(stream, state);
+  } else {
+    var er;
+    if (!skipChunkCheck) er = chunkInvalid(state, chunk);
+    if (er) {
+      stream.emit('error', er);
+    } else if (state.objectMode || chunk && chunk.length > 0) {
+      if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
+        chunk = _uint8ArrayToBuffer(chunk);
+      }
+
+      if (addToFront) {
+        if (state.endEmitted) stream.emit('error', new Error('stream.unshift() after end event'));else addChunk(stream, state, chunk, true);
+      } else if (state.ended) {
+        stream.emit('error', new Error('stream.push() after EOF'));
+      } else {
+        state.reading = false;
+        if (state.decoder && !encoding) {
+          chunk = state.decoder.write(chunk);
+          if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
+        } else {
+          addChunk(stream, state, chunk, false);
+        }
+      }
+    } else if (!addToFront) {
+      state.reading = false;
+    }
+  }
+
+  return needMoreData(state);
+}
+
+function addChunk(stream, state, chunk, addToFront) {
+  if (state.flowing && state.length === 0 && !state.sync) {
+    stream.emit('data', chunk);
+    stream.read(0);
+  } else {
+    // update the buffer info.
+    state.length += state.objectMode ? 1 : chunk.length;
+    if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);
+
+    if (state.needReadable) emitReadable(stream);
+  }
+  maybeReadMore(stream, state);
+}
+
+function chunkInvalid(state, chunk) {
+  var er;
+  if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
+    er = new TypeError('Invalid non-string/buffer chunk');
+  }
+  return er;
+}
+
+// if it's past the high water mark, we can push in some more.
+// Also, if we have no data yet, we can stand some
+// more bytes.  This is to work around cases where hwm=0,
+// such as the repl.  Also, if the push() triggered a
+// readable event, and the user called read(largeNumber) such that
+// needReadable was set, then we ought to push more, so that another
+// 'readable' event will be triggered.
+function needMoreData(state) {
+  return !state.ended && (state.needReadable || state.length < state.highWaterMark || state.length === 0);
+}
+
+Readable.prototype.isPaused = function () {
+  return this._readableState.flowing === false;
+};
+
+// backwards compatibility.
+Readable.prototype.setEncoding = function (enc) {
+  if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+  this._readableState.decoder = new StringDecoder(enc);
+  this._readableState.encoding = enc;
+  return this;
+};
+
+// Don't raise the hwm > 8MB
+var MAX_HWM = 0x800000;
+function computeNewHighWaterMark(n) {
+  if (n >= MAX_HWM) {
+    n = MAX_HWM;
+  } else {
+    // Get the next highest power of 2 to prevent increasing hwm excessively in
+    // tiny amounts
+    n--;
+    n |= n >>> 1;
+    n |= n >>> 2;
+    n |= n >>> 4;
+    n |= n >>> 8;
+    n |= n >>> 16;
+    n++;
+  }
+  return n;
+}
+
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function howMuchToRead(n, state) {
+  if (n <= 0 || state.length === 0 && state.ended) return 0;
+  if (state.objectMode) return 1;
+  if (n !== n) {
+    // Only flow one buffer at a time
+    if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
+  }
+  // If we're asking for more than the current hwm, then raise the hwm.
+  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
+  if (n <= state.length) return n;
+  // Don't have enough
+  if (!state.ended) {
+    state.needReadable = true;
+    return 0;
+  }
+  return state.length;
+}
+
+// you can override either this method, or the async _read(n) below.
+Readable.prototype.read = function (n) {
+  debug('read', n);
+  n = parseInt(n, 10);
+  var state = this._readableState;
+  var nOrig = n;
+
+  if (n !== 0) state.emittedReadable = false;
+
+  // if we're doing read(0) to trigger a readable event, but we
+  // already have a bunch of data in the buffer, then just trigger
+  // the 'readable' event and move on.
+  if (n === 0 && state.needReadable && (state.length >= state.highWaterMark || state.ended)) {
+    debug('read: emitReadable', state.length, state.ended);
+    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
+    return null;
+  }
+
+  n = howMuchToRead(n, state);
+
+  // if we've ended, and we're now clear, then finish it up.
+  if (n === 0 && state.ended) {
+    if (state.length === 0) endReadable(this);
+    return null;
+  }
+
+  // All the actual chunk generation logic needs to be
+  // *below* the call to _read.  The reason is that in certain
+  // synthetic stream cases, such as passthrough streams, _read
+  // may be a completely synchronous operation which may change
+  // the state of the read buffer, providing enough data when
+  // before there was *not* enough.
+  //
+  // So, the steps are:
+  // 1. Figure out what the state of things will be after we do
+  // a read from the buffer.
+  //
+  // 2. If that resulting state will trigger a _read, then call _read.
+  // Note that this may be asynchronous, or synchronous.  Yes, it is
+  // deeply ugly to write APIs this way, but that still doesn't mean
+  // that the Readable class should behave improperly, as streams are
+  // designed to be sync/async agnostic.
+  // Take note if the _read call is sync or async (ie, if the read call
+  // has returned yet), so that we know whether or not it's safe to emit
+  // 'readable' etc.
+  //
+  // 3. Actually pull the requested chunks out of the buffer and return.
+
+  // if we need a readable event, then we need to do some reading.
+  var doRead = state.needReadable;
+  debug('need readable', doRead);
+
+  // if we currently have less than the highWaterMark, then also read some
+  if (state.length === 0 || state.length - n < state.highWaterMark) {
+    doRead = true;
+    debug('length less than watermark', doRead);
+  }
+
+  // however, if we've ended, then there's no point, and if we're already
+  // reading, then it's unnecessary.
+  if (state.ended || state.reading) {
+    doRead = false;
+    debug('reading or ended', doRead);
+  } else if (doRead) {
+    debug('do read');
+    state.reading = true;
+    state.sync = true;
+    // if the length is currently zero, then we *need* a readable event.
+    if (state.length === 0) state.needReadable = true;
+    // call internal read method
+    this._read(state.highWaterMark);
+    state.sync = false;
+    // If _read pushed data synchronously, then `reading` will be false,
+    // and we need to re-evaluate how much data we can return to the user.
+    if (!state.reading) n = howMuchToRead(nOrig, state);
+  }
+
+  var ret;
+  if (n > 0) ret = fromList(n, state);else ret = null;
+
+  if (ret === null) {
+    state.needReadable = true;
+    n = 0;
+  } else {
+    state.length -= n;
+  }
+
+  if (state.length === 0) {
+    // If we have nothing in the buffer, then we want to know
+    // as soon as we *do* get something into the buffer.
+    if (!state.ended) state.needReadable = true;
+
+    // If we tried to read() past the EOF, then emit end on the next tick.
+    if (nOrig !== n && state.ended) endReadable(this);
+  }
+
+  if (ret !== null) this.emit('data', ret);
+
+  return ret;
+};
+
+function onEofChunk(stream, state) {
+  if (state.ended) return;
+  if (state.decoder) {
+    var chunk = state.decoder.end();
+    if (chunk && chunk.length) {
+      state.buffer.push(chunk);
+      state.length += state.objectMode ? 1 : chunk.length;
+    }
+  }
+  state.ended = true;
+
+  // emit 'readable' now to make sure it gets picked up.
+  emitReadable(stream);
+}
+
+// Don't emit readable right away in sync mode, because this can trigger
+// another read() call => stack overflow.  This way, it might trigger
+// a nextTick recursion warning, but that's not so bad.
+function emitReadable(stream) {
+  var state = stream._readableState;
+  state.needReadable = false;
+  if (!state.emittedReadable) {
+    debug('emitReadable', state.flowing);
+    state.emittedReadable = true;
+    if (state.sync) pna.nextTick(emitReadable_, stream);else emitReadable_(stream);
+  }
+}
+
+function emitReadable_(stream) {
+  debug('emit readable');
+  stream.emit('readable');
+  flow(stream);
+}
+
+// at this point, the user has presumably seen the 'readable' event,
+// and called read() to consume some data.  that may have triggered
+// in turn another _read(n) call, in which case reading = true if
+// it's in progress.
+// However, if we're not ended, or reading, and the length < hwm,
+// then go ahead and try to read some more preemptively.
+function maybeReadMore(stream, state) {
+  if (!state.readingMore) {
+    state.readingMore = true;
+    pna.nextTick(maybeReadMore_, stream, state);
+  }
+}
+
+function maybeReadMore_(stream, state) {
+  var len = state.length;
+  while (!state.reading && !state.flowing && !state.ended && state.length < state.highWaterMark) {
+    debug('maybeReadMore read 0');
+    stream.read(0);
+    if (len === state.length)
+      // didn't get any data, stop spinning.
+      break;else len = state.length;
+  }
+  state.readingMore = false;
+}
+
+// abstract method.  to be overridden in specific implementation classes.
+// call cb(er, data) where data is <= n in length.
+// for virtual (non-string, non-buffer) streams, "length" is somewhat
+// arbitrary, and perhaps not very meaningful.
+Readable.prototype._read = function (n) {
+  this.emit('error', new Error('_read() is not implemented'));
+};
+
+Readable.prototype.pipe = function (dest, pipeOpts) {
+  var src = this;
+  var state = this._readableState;
+
+  switch (state.pipesCount) {
+    case 0:
+      state.pipes = dest;
+      break;
+    case 1:
+      state.pipes = [state.pipes, dest];
+      break;
+    default:
+      state.pipes.push(dest);
+      break;
+  }
+  state.pipesCount += 1;
+  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
+
+  var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;
+
+  var endFn = doEnd ? onend : unpipe;
+  if (state.endEmitted) pna.nextTick(endFn);else src.once('end', endFn);
+
+  dest.on('unpipe', onunpipe);
+  function onunpipe(readable, unpipeInfo) {
+    debug('onunpipe');
+    if (readable === src) {
+      if (unpipeInfo && unpipeInfo.hasUnpiped === false) {
+        unpipeInfo.hasUnpiped = true;
+        cleanup();
+      }
+    }
+  }
+
+  function onend() {
+    debug('onend');
+    dest.end();
+  }
+
+  // when the dest drains, it reduces the awaitDrain counter
+  // on the source.  This would be more elegant with a .once()
+  // handler in flow(), but adding and removing repeatedly is
+  // too slow.
+  var ondrain = pipeOnDrain(src);
+  dest.on('drain', ondrain);
+
+  var cleanedUp = false;
+  function cleanup() {
+    debug('cleanup');
+    // cleanup event handlers once the pipe is broken
+    dest.removeListener('close', onclose);
+    dest.removeListener('finish', onfinish);
+    dest.removeListener('drain', ondrain);
+    dest.removeListener('error', onerror);
+    dest.removeListener('unpipe', onunpipe);
+    src.removeListener('end', onend);
+    src.removeListener('end', unpipe);
+    src.removeListener('data', ondata);
+
+    cleanedUp = true;
+
+    // if the reader is waiting for a drain event from this
+    // specific writer, then it would cause it to never start
+    // flowing again.
+    // So, if this is awaiting a drain, then we just call it now.
+    // If we don't know, then assume that we are waiting for one.
+    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
+  }
+
+  // If the user pushes more data while we're writing to dest then we'll end up
+  // in ondata again. However, we only want to increase awaitDrain once because
+  // dest will only emit one 'drain' event for the multiple writes.
+  // => Introduce a guard on increasing awaitDrain.
+  var increasedAwaitDrain = false;
+  src.on('data', ondata);
+  function ondata(chunk) {
+    debug('ondata');
+    increasedAwaitDrain = false;
+    var ret = dest.write(chunk);
+    if (false === ret && !increasedAwaitDrain) {
+      // If the user unpiped during `dest.write()`, it is possible
+      // to get stuck in a permanently paused state if that write
+      // also returned false.
+      // => Check whether `dest` is still a piping destination.
+      if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
+        debug('false write response, pause', state.awaitDrain);
+        state.awaitDrain++;
+        increasedAwaitDrain = true;
+      }
+      src.pause();
+    }
+  }
+
+  // if the dest has an error, then stop piping into it.
+  // however, don't suppress the throwing behavior for this.
+  function onerror(er) {
+    debug('onerror', er);
+    unpipe();
+    dest.removeListener('error', onerror);
+    if (EElistenerCount(dest, 'error') === 0) dest.emit('error', er);
+  }
+
+  // Make sure our error handler is attached before userland ones.
+  prependListener(dest, 'error', onerror);
+
+  // Both close and finish should trigger unpipe, but only once.
+  function onclose() {
+    dest.removeListener('finish', onfinish);
+    unpipe();
+  }
+  dest.once('close', onclose);
+  function onfinish() {
+    debug('onfinish');
+    dest.removeListener('close', onclose);
+    unpipe();
+  }
+  dest.once('finish', onfinish);
+
+  function unpipe() {
+    debug('unpipe');
+    src.unpipe(dest);
+  }
+
+  // tell the dest that it's being piped to
+  dest.emit('pipe', src);
+
+  // start the flow if it hasn't been started already.
+  if (!state.flowing) {
+    debug('pipe resume');
+    src.resume();
+  }
+
+  return dest;
+};
+
+function pipeOnDrain(src) {
+  return function () {
+    var state = src._readableState;
+    debug('pipeOnDrain', state.awaitDrain);
+    if (state.awaitDrain) state.awaitDrain--;
+    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
+      state.flowing = true;
+      flow(src);
+    }
+  };
+}
+
+Readable.prototype.unpipe = function (dest) {
+  var state = this._readableState;
+  var unpipeInfo = { hasUnpiped: false };
+
+  // if we're not piping anywhere, then do nothing.
+  if (state.pipesCount === 0) return this;
+
+  // just one destination.  most common case.
+  if (state.pipesCount === 1) {
+    // passed in one, but it's not the right one.
+    if (dest && dest !== state.pipes) return this;
+
+    if (!dest) dest = state.pipes;
+
+    // got a match.
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    if (dest) dest.emit('unpipe', this, unpipeInfo);
+    return this;
+  }
+
+  // slow case. multiple pipe destinations.
+
+  if (!dest) {
+    // remove all.
+    var dests = state.pipes;
+    var len = state.pipesCount;
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+
+    for (var i = 0; i < len; i++) {
+      dests[i].emit('unpipe', this, { hasUnpiped: false });
+    }return this;
+  }
+
+  // try to find the right one.
+  var index = indexOf(state.pipes, dest);
+  if (index === -1) return this;
+
+  state.pipes.splice(index, 1);
+  state.pipesCount -= 1;
+  if (state.pipesCount === 1) state.pipes = state.pipes[0];
+
+  dest.emit('unpipe', this, unpipeInfo);
+
+  return this;
+};
+
+// set up data events if they are asked for
+// Ensure readable listeners eventually get something
+Readable.prototype.on = function (ev, fn) {
+  var res = Stream.prototype.on.call(this, ev, fn);
+
+  if (ev === 'data') {
+    // Start flowing on next tick if stream isn't explicitly paused
+    if (this._readableState.flowing !== false) this.resume();
+  } else if (ev === 'readable') {
+    var state = this._readableState;
+    if (!state.endEmitted && !state.readableListening) {
+      state.readableListening = state.needReadable = true;
+      state.emittedReadable = false;
+      if (!state.reading) {
+        pna.nextTick(nReadingNextTick, this);
+      } else if (state.length) {
+        emitReadable(this);
+      }
+    }
+  }
+
+  return res;
+};
+Readable.prototype.addListener = Readable.prototype.on;
+
+function nReadingNextTick(self) {
+  debug('readable nexttick read 0');
+  self.read(0);
+}
+
+// pause() and resume() are remnants of the legacy readable stream API
+// If the user uses them, then switch into old mode.
+Readable.prototype.resume = function () {
+  var state = this._readableState;
+  if (!state.flowing) {
+    debug('resume');
+    state.flowing = true;
+    resume(this, state);
+  }
+  return this;
+};
+
+function resume(stream, state) {
+  if (!state.resumeScheduled) {
+    state.resumeScheduled = true;
+    pna.nextTick(resume_, stream, state);
+  }
+}
+
+function resume_(stream, state) {
+  if (!state.reading) {
+    debug('resume read 0');
+    stream.read(0);
+  }
+
+  state.resumeScheduled = false;
+  state.awaitDrain = 0;
+  stream.emit('resume');
+  flow(stream);
+  if (state.flowing && !state.reading) stream.read(0);
+}
+
+Readable.prototype.pause = function () {
+  debug('call pause flowing=%j', this._readableState.flowing);
+  if (false !== this._readableState.flowing) {
+    debug('pause');
+    this._readableState.flowing = false;
+    this.emit('pause');
+  }
+  return this;
+};
+
+function flow(stream) {
+  var state = stream._readableState;
+  debug('flow', state.flowing);
+  while (state.flowing && stream.read() !== null) {}
+}
+
+// wrap an old-style stream as the async data source.
+// This is *not* part of the readable stream interface.
+// It is an ugly unfortunate mess of history.
+Readable.prototype.wrap = function (stream) {
+  var _this = this;
+
+  var state = this._readableState;
+  var paused = false;
+
+  stream.on('end', function () {
+    debug('wrapped end');
+    if (state.decoder && !state.ended) {
+      var chunk = state.decoder.end();
+      if (chunk && chunk.length) _this.push(chunk);
+    }
+
+    _this.push(null);
+  });
+
+  stream.on('data', function (chunk) {
+    debug('wrapped data');
+    if (state.decoder) chunk = state.decoder.write(chunk);
+
+    // don't skip over falsy values in objectMode
+    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;
+
+    var ret = _this.push(chunk);
+    if (!ret) {
+      paused = true;
+      stream.pause();
+    }
+  });
+
+  // proxy all the other methods.
+  // important when wrapping filters and duplexes.
+  for (var i in stream) {
+    if (this[i] === undefined && typeof stream[i] === 'function') {
+      this[i] = function (method) {
+        return function () {
+          return stream[method].apply(stream, arguments);
+        };
+      }(i);
+    }
+  }
+
+  // proxy certain important events.
+  for (var n = 0; n < kProxyEvents.length; n++) {
+    stream.on(kProxyEvents[n], this.emit.bind(this, kProxyEvents[n]));
+  }
+
+  // when we try to consume some more bytes, simply unpause the
+  // underlying stream.
+  this._read = function (n) {
+    debug('wrapped _read', n);
+    if (paused) {
+      paused = false;
+      stream.resume();
+    }
+  };
+
+  return this;
+};
+
+Object.defineProperty(Readable.prototype, 'readableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function () {
+    return this._readableState.highWaterMark;
+  }
+});
+
+// exposed for testing purposes only.
+Readable._fromList = fromList;
+
+// Pluck off n bytes from an array of buffers.
+// Length is the combined lengths of all the buffers in the list.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function fromList(n, state) {
+  // nothing buffered
+  if (state.length === 0) return null;
+
+  var ret;
+  if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
+    // read it all, truncate the list
+    if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.head.data;else ret = state.buffer.concat(state.length);
+    state.buffer.clear();
+  } else {
+    // read part of list
+    ret = fromListPartial(n, state.buffer, state.decoder);
+  }
+
+  return ret;
+}
+
+// Extracts only enough buffered data to satisfy the amount requested.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function fromListPartial(n, list, hasStrings) {
+  var ret;
+  if (n < list.head.data.length) {
+    // slice is the same for buffers and strings
+    ret = list.head.data.slice(0, n);
+    list.head.data = list.head.data.slice(n);
+  } else if (n === list.head.data.length) {
+    // first chunk is a perfect match
+    ret = list.shift();
+  } else {
+    // result spans more than one buffer
+    ret = hasStrings ? copyFromBufferString(n, list) : copyFromBuffer(n, list);
+  }
+  return ret;
+}
+
+// Copies a specified amount of characters from the list of buffered data
+// chunks.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function copyFromBufferString(n, list) {
+  var p = list.head;
+  var c = 1;
+  var ret = p.data;
+  n -= ret.length;
+  while (p = p.next) {
+    var str = p.data;
+    var nb = n > str.length ? str.length : n;
+    if (nb === str.length) ret += str;else ret += str.slice(0, n);
+    n -= nb;
+    if (n === 0) {
+      if (nb === str.length) {
+        ++c;
+        if (p.next) list.head = p.next;else list.head = list.tail = null;
+      } else {
+        list.head = p;
+        p.data = str.slice(nb);
+      }
+      break;
+    }
+    ++c;
+  }
+  list.length -= c;
+  return ret;
+}
+
+// Copies a specified amount of bytes from the list of buffered data chunks.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function copyFromBuffer(n, list) {
+  var ret = Buffer.allocUnsafe(n);
+  var p = list.head;
+  var c = 1;
+  p.data.copy(ret);
+  n -= p.data.length;
+  while (p = p.next) {
+    var buf = p.data;
+    var nb = n > buf.length ? buf.length : n;
+    buf.copy(ret, ret.length - n, 0, nb);
+    n -= nb;
+    if (n === 0) {
+      if (nb === buf.length) {
+        ++c;
+        if (p.next) list.head = p.next;else list.head = list.tail = null;
+      } else {
+        list.head = p;
+        p.data = buf.slice(nb);
+      }
+      break;
+    }
+    ++c;
+  }
+  list.length -= c;
+  return ret;
+}
+
+function endReadable(stream) {
+  var state = stream._readableState;
+
+  // If we get here before consuming all the bytes, then that is a
+  // bug in node.  Should never happen.
+  if (state.length > 0) throw new Error('"endReadable()" called on non-empty stream');
+
+  if (!state.endEmitted) {
+    state.ended = true;
+    pna.nextTick(endReadableNT, state, stream);
+  }
+}
+
+function endReadableNT(state, stream) {
+  // Check that we didn't get one last unshift.
+  if (!state.endEmitted && state.length === 0) {
+    state.endEmitted = true;
+    stream.readable = false;
+    stream.emit('end');
+  }
+}
+
+function indexOf(xs, x) {
+  for (var i = 0, l = xs.length; i < l; i++) {
+    if (xs[i] === x) return i;
+  }
+  return -1;
+}
\ No newline at end of file
diff --git a/server/node_modules/readable-stream/lib/_stream_transform.js b/server/node_modules/readable-stream/lib/_stream_transform.js
new file mode 100644
index 0000000..fcfc105
--- /dev/null
+++ b/server/node_modules/readable-stream/lib/_stream_transform.js
@@ -0,0 +1,214 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a transform stream is a readable/writable stream where you do
+// something with the data.  Sometimes it's called a "filter",
+// but that's not a great name for it, since that implies a thing where
+// some bits pass through, and others are simply ignored.  (That would
+// be a valid example of a transform, of course.)
+//
+// While the output is causally related to the input, it's not a
+// necessarily symmetric or synchronous transformation.  For example,
+// a zlib stream might take multiple plain-text writes(), and then
+// emit a single compressed chunk some time in the future.
+//
+// Here's how this works:
+//
+// The Transform stream has all the aspects of the readable and writable
+// stream classes.  When you write(chunk), that calls _write(chunk,cb)
+// internally, and returns false if there's a lot of pending writes
+// buffered up.  When you call read(), that calls _read(n) until
+// there's enough pending readable data buffered up.
+//
+// In a transform stream, the written data is placed in a buffer.  When
+// _read(n) is called, it transforms the queued up data, calling the
+// buffered _write cb's as it consumes chunks.  If consuming a single
+// written chunk would result in multiple output chunks, then the first
+// outputted bit calls the readcb, and subsequent chunks just go into
+// the read buffer, and will cause it to emit 'readable' if necessary.
+//
+// This way, back-pressure is actually determined by the reading side,
+// since _read has to be called to start processing a new chunk.  However,
+// a pathological inflate type of transform can cause excessive buffering
+// here.  For example, imagine a stream where every byte of input is
+// interpreted as an integer from 0-255, and then results in that many
+// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
+// 1kb of data being output.  In this case, you could write a very small
+// amount of input, and end up with a very large amount of output.  In
+// such a pathological inflating mechanism, there'd be no way to tell
+// the system to stop doing the transform.  A single 4MB write could
+// cause the system to run out of memory.
+//
+// However, even in such a pathological case, only a single written chunk
+// would be consumed, and then the rest would wait (un-transformed) until
+// the results of the previous transformed chunk were consumed.
+
+'use strict';
+
+module.exports = Transform;
+
+var Duplex = require('./_stream_duplex');
+
+/*<replacement>*/
+var util = Object.create(require('core-util-is'));
+util.inherits = require('inherits');
+/*</replacement>*/
+
+util.inherits(Transform, Duplex);
+
+function afterTransform(er, data) {
+  var ts = this._transformState;
+  ts.transforming = false;
+
+  var cb = ts.writecb;
+
+  if (!cb) {
+    return this.emit('error', new Error('write callback called multiple times'));
+  }
+
+  ts.writechunk = null;
+  ts.writecb = null;
+
+  if (data != null) // single equals check for both `null` and `undefined`
+    this.push(data);
+
+  cb(er);
+
+  var rs = this._readableState;
+  rs.reading = false;
+  if (rs.needReadable || rs.length < rs.highWaterMark) {
+    this._read(rs.highWaterMark);
+  }
+}
+
+function Transform(options) {
+  if (!(this instanceof Transform)) return new Transform(options);
+
+  Duplex.call(this, options);
+
+  this._transformState = {
+    afterTransform: afterTransform.bind(this),
+    needTransform: false,
+    transforming: false,
+    writecb: null,
+    writechunk: null,
+    writeencoding: null
+  };
+
+  // start out asking for a readable event once data is transformed.
+  this._readableState.needReadable = true;
+
+  // we have implemented the _read method, and done the other things
+  // that Readable wants before the first _read call, so unset the
+  // sync guard flag.
+  this._readableState.sync = false;
+
+  if (options) {
+    if (typeof options.transform === 'function') this._transform = options.transform;
+
+    if (typeof options.flush === 'function') this._flush = options.flush;
+  }
+
+  // When the writable side finishes, then flush out anything remaining.
+  this.on('prefinish', prefinish);
+}
+
+function prefinish() {
+  var _this = this;
+
+  if (typeof this._flush === 'function') {
+    this._flush(function (er, data) {
+      done(_this, er, data);
+    });
+  } else {
+    done(this, null, null);
+  }
+}
+
+Transform.prototype.push = function (chunk, encoding) {
+  this._transformState.needTransform = false;
+  return Duplex.prototype.push.call(this, chunk, encoding);
+};
+
+// This is the part where you do stuff!
+// override this function in implementation classes.
+// 'chunk' is an input chunk.
+//
+// Call `push(newChunk)` to pass along transformed output
+// to the readable side.  You may call 'push' zero or more times.
+//
+// Call `cb(err)` when you are done with this chunk.  If you pass
+// an error, then that'll put the hurt on the whole operation.  If you
+// never call cb(), then you'll never get another chunk.
+Transform.prototype._transform = function (chunk, encoding, cb) {
+  throw new Error('_transform() is not implemented');
+};
+
+Transform.prototype._write = function (chunk, encoding, cb) {
+  var ts = this._transformState;
+  ts.writecb = cb;
+  ts.writechunk = chunk;
+  ts.writeencoding = encoding;
+  if (!ts.transforming) {
+    var rs = this._readableState;
+    if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
+  }
+};
+
+// Doesn't matter what the args are here.
+// _transform does all the work.
+// That we got here means that the readable side wants more data.
+Transform.prototype._read = function (n) {
+  var ts = this._transformState;
+
+  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
+    ts.transforming = true;
+    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
+  } else {
+    // mark that we need a transform, so that any data that comes in
+    // will get processed, now that we've asked for it.
+    ts.needTransform = true;
+  }
+};
+
+Transform.prototype._destroy = function (err, cb) {
+  var _this2 = this;
+
+  Duplex.prototype._destroy.call(this, err, function (err2) {
+    cb(err2);
+    _this2.emit('close');
+  });
+};
+
+function done(stream, er, data) {
+  if (er) return stream.emit('error', er);
+
+  if (data != null) // single equals check for both `null` and `undefined`
+    stream.push(data);
+
+  // if there's nothing in the write buffer, then that means
+  // that nothing more will ever be provided
+  if (stream._writableState.length) throw new Error('Calling transform done when ws.length != 0');
+
+  if (stream._transformState.transforming) throw new Error('Calling transform done when still transforming');
+
+  return stream.push(null);
+}
\ No newline at end of file
diff --git a/server/node_modules/readable-stream/lib/_stream_writable.js b/server/node_modules/readable-stream/lib/_stream_writable.js
new file mode 100644
index 0000000..e1e897f
--- /dev/null
+++ b/server/node_modules/readable-stream/lib/_stream_writable.js
@@ -0,0 +1,685 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// A bit simpler than readable streams.
+// Implement an async ._write(chunk, encoding, cb), and it'll handle all
+// the drain event emission and buffering.
+
+'use strict';
+
+/*<replacement>*/
+
+var pna = require('process-nextick-args');
+/*</replacement>*/
+
+module.exports = Writable;
+
+/* <replacement> */
+function WriteReq(chunk, encoding, cb) {
+  this.chunk = chunk;
+  this.encoding = encoding;
+  this.callback = cb;
+  this.next = null;
+}
+
+// It seems a linked list but it is not
+// there will be only 2 of these for each stream
+function CorkedRequest(state) {
+  var _this = this;
+
+  this.next = null;
+  this.entry = null;
+  this.finish = function () {
+    onCorkedFinish(_this, state);
+  };
+}
+/* </replacement> */
+
+/*<replacement>*/
+var asyncWrite = !process.browser && ['v0.10', 'v0.9.'].indexOf(process.version.slice(0, 5)) > -1 ? setImmediate : pna.nextTick;
+/*</replacement>*/
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Writable.WritableState = WritableState;
+
+/*<replacement>*/
+var util = Object.create(require('core-util-is'));
+util.inherits = require('inherits');
+/*</replacement>*/
+
+/*<replacement>*/
+var internalUtil = {
+  deprecate: require('util-deprecate')
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+/*<replacement>*/
+
+var Buffer = require('safe-buffer').Buffer;
+var OurUint8Array = (typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : typeof self !== 'undefined' ? self : {}).Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+
+/*</replacement>*/
+
+var destroyImpl = require('./internal/streams/destroy');
+
+util.inherits(Writable, Stream);
+
+function nop() {}
+
+function WritableState(options, stream) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream.
+  // These options can be provided separately as readableXXX and writableXXX.
+  var isDuplex = stream instanceof Duplex;
+
+  // object stream flag to indicate whether or not this stream
+  // contains buffers or objects.
+  this.objectMode = !!options.objectMode;
+
+  if (isDuplex) this.objectMode = this.objectMode || !!options.writableObjectMode;
+
+  // the point at which write() starts returning false
+  // Note: 0 is a valid value, means that we always return false if
+  // the entire buffer is not flushed immediately on write()
+  var hwm = options.highWaterMark;
+  var writableHwm = options.writableHighWaterMark;
+  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
+
+  if (hwm || hwm === 0) this.highWaterMark = hwm;else if (isDuplex && (writableHwm || writableHwm === 0)) this.highWaterMark = writableHwm;else this.highWaterMark = defaultHwm;
+
+  // cast to ints.
+  this.highWaterMark = Math.floor(this.highWaterMark);
+
+  // if _final has been called
+  this.finalCalled = false;
+
+  // drain event flag.
+  this.needDrain = false;
+  // at the start of calling end()
+  this.ending = false;
+  // when end() has been called, and returned
+  this.ended = false;
+  // when 'finish' is emitted
+  this.finished = false;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // should we decode strings into buffers before passing to _write?
+  // this is here so that some node-core streams can optimize string
+  // handling at a lower level.
+  var noDecode = options.decodeStrings === false;
+  this.decodeStrings = !noDecode;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // not an actual buffer we keep track of, but a measurement
+  // of how much we're waiting to get pushed to some underlying
+  // socket or file.
+  this.length = 0;
+
+  // a flag to see when we're in the middle of a write.
+  this.writing = false;
+
+  // when true all writes will be buffered until .uncork() call
+  this.corked = 0;
+
+  // a flag to be able to tell if the onwrite cb is called immediately,
+  // or on a later tick.  We set this to true at first, because any
+  // actions that shouldn't happen until "later" should generally also
+  // not happen before the first write call.
+  this.sync = true;
+
+  // a flag to know if we're processing previously buffered items, which
+  // may call the _write() callback in the same tick, so that we don't
+  // end up in an overlapped onwrite situation.
+  this.bufferProcessing = false;
+
+  // the callback that's passed to _write(chunk,cb)
+  this.onwrite = function (er) {
+    onwrite(stream, er);
+  };
+
+  // the callback that the user supplies to write(chunk,encoding,cb)
+  this.writecb = null;
+
+  // the amount that is being written when _write is called.
+  this.writelen = 0;
+
+  this.bufferedRequest = null;
+  this.lastBufferedRequest = null;
+
+  // number of pending user-supplied write callbacks
+  // this must be 0 before 'finish' can be emitted
+  this.pendingcb = 0;
+
+  // emit prefinish if the only thing we're waiting for is _write cbs
+  // This is relevant for synchronous Transform streams
+  this.prefinished = false;
+
+  // True if the error was already emitted and should not be thrown again
+  this.errorEmitted = false;
+
+  // count buffered requests
+  this.bufferedRequestCount = 0;
+
+  // allocate the first CorkedRequest, there is always
+  // one allocated and free to use, and we maintain at most two
+  this.corkedRequestsFree = new CorkedRequest(this);
+}
+
+WritableState.prototype.getBuffer = function getBuffer() {
+  var current = this.bufferedRequest;
+  var out = [];
+  while (current) {
+    out.push(current);
+    current = current.next;
+  }
+  return out;
+};
+
+(function () {
+  try {
+    Object.defineProperty(WritableState.prototype, 'buffer', {
+      get: internalUtil.deprecate(function () {
+        return this.getBuffer();
+      }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.', 'DEP0003')
+    });
+  } catch (_) {}
+})();
+
+// Test _writableState for inheritance to account for Duplex streams,
+// whose prototype chain only points to Readable.
+var realHasInstance;
+if (typeof Symbol === 'function' && Symbol.hasInstance && typeof Function.prototype[Symbol.hasInstance] === 'function') {
+  realHasInstance = Function.prototype[Symbol.hasInstance];
+  Object.defineProperty(Writable, Symbol.hasInstance, {
+    value: function (object) {
+      if (realHasInstance.call(this, object)) return true;
+      if (this !== Writable) return false;
+
+      return object && object._writableState instanceof WritableState;
+    }
+  });
+} else {
+  realHasInstance = function (object) {
+    return object instanceof this;
+  };
+}
+
+function Writable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  // Writable ctor is applied to Duplexes, too.
+  // `realHasInstance` is necessary because using plain `instanceof`
+  // would return false, as no `_writableState` property is attached.
+
+  // Trying to use the custom `instanceof` for Writable here will also break the
+  // Node.js LazyTransform implementation, which has a non-trivial getter for
+  // `_writableState` that would lead to infinite recursion.
+  if (!realHasInstance.call(Writable, this) && !(this instanceof Duplex)) {
+    return new Writable(options);
+  }
+
+  this._writableState = new WritableState(options, this);
+
+  // legacy.
+  this.writable = true;
+
+  if (options) {
+    if (typeof options.write === 'function') this._write = options.write;
+
+    if (typeof options.writev === 'function') this._writev = options.writev;
+
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+
+    if (typeof options.final === 'function') this._final = options.final;
+  }
+
+  Stream.call(this);
+}
+
+// Otherwise people can pipe Writable streams, which is just wrong.
+Writable.prototype.pipe = function () {
+  this.emit('error', new Error('Cannot pipe, not readable'));
+};
+
+function writeAfterEnd(stream, cb) {
+  var er = new Error('write after end');
+  // TODO: defer error events consistently everywhere, not just the cb
+  stream.emit('error', er);
+  pna.nextTick(cb, er);
+}
+
+// Checks that a user-supplied chunk is valid, especially for the particular
+// mode the stream is in. Currently this means that `null` is never accepted
+// and undefined/non-string values are only allowed in object mode.
+function validChunk(stream, state, chunk, cb) {
+  var valid = true;
+  var er = false;
+
+  if (chunk === null) {
+    er = new TypeError('May not write null values to stream');
+  } else if (typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
+    er = new TypeError('Invalid non-string/buffer chunk');
+  }
+  if (er) {
+    stream.emit('error', er);
+    pna.nextTick(cb, er);
+    valid = false;
+  }
+  return valid;
+}
+
+Writable.prototype.write = function (chunk, encoding, cb) {
+  var state = this._writableState;
+  var ret = false;
+  var isBuf = !state.objectMode && _isUint8Array(chunk);
+
+  if (isBuf && !Buffer.isBuffer(chunk)) {
+    chunk = _uint8ArrayToBuffer(chunk);
+  }
+
+  if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+
+  if (isBuf) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;
+
+  if (typeof cb !== 'function') cb = nop;
+
+  if (state.ended) writeAfterEnd(this, cb);else if (isBuf || validChunk(this, state, chunk, cb)) {
+    state.pendingcb++;
+    ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
+  }
+
+  return ret;
+};
+
+Writable.prototype.cork = function () {
+  var state = this._writableState;
+
+  state.corked++;
+};
+
+Writable.prototype.uncork = function () {
+  var state = this._writableState;
+
+  if (state.corked) {
+    state.corked--;
+
+    if (!state.writing && !state.corked && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
+  }
+};
+
+Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
+  // node::ParseEncoding() requires lower case.
+  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
+  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new TypeError('Unknown encoding: ' + encoding);
+  this._writableState.defaultEncoding = encoding;
+  return this;
+};
+
+function decodeChunk(state, chunk, encoding) {
+  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
+    chunk = Buffer.from(chunk, encoding);
+  }
+  return chunk;
+}
+
+Object.defineProperty(Writable.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function () {
+    return this._writableState.highWaterMark;
+  }
+});
+
+// if we're already writing something, then just put this
+// in the queue, and wait our turn.  Otherwise, call _write
+// If we return false, then we need a drain event, so set that flag.
+function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
+  if (!isBuf) {
+    var newChunk = decodeChunk(state, chunk, encoding);
+    if (chunk !== newChunk) {
+      isBuf = true;
+      encoding = 'buffer';
+      chunk = newChunk;
+    }
+  }
+  var len = state.objectMode ? 1 : chunk.length;
+
+  state.length += len;
+
+  var ret = state.length < state.highWaterMark;
+  // we must ensure that previous needDrain will not be reset to false.
+  if (!ret) state.needDrain = true;
+
+  if (state.writing || state.corked) {
+    var last = state.lastBufferedRequest;
+    state.lastBufferedRequest = {
+      chunk: chunk,
+      encoding: encoding,
+      isBuf: isBuf,
+      callback: cb,
+      next: null
+    };
+    if (last) {
+      last.next = state.lastBufferedRequest;
+    } else {
+      state.bufferedRequest = state.lastBufferedRequest;
+    }
+    state.bufferedRequestCount += 1;
+  } else {
+    doWrite(stream, state, false, len, chunk, encoding, cb);
+  }
+
+  return ret;
+}
+
+function doWrite(stream, state, writev, len, chunk, encoding, cb) {
+  state.writelen = len;
+  state.writecb = cb;
+  state.writing = true;
+  state.sync = true;
+  if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
+  state.sync = false;
+}
+
+function onwriteError(stream, state, sync, er, cb) {
+  --state.pendingcb;
+
+  if (sync) {
+    // defer the callback if we are being called synchronously
+    // to avoid piling up things on the stack
+    pna.nextTick(cb, er);
+    // this can emit finish, and it will always happen
+    // after error
+    pna.nextTick(finishMaybe, stream, state);
+    stream._writableState.errorEmitted = true;
+    stream.emit('error', er);
+  } else {
+    // the caller expect this to happen before if
+    // it is async
+    cb(er);
+    stream._writableState.errorEmitted = true;
+    stream.emit('error', er);
+    // this can emit finish, but finish must
+    // always follow error
+    finishMaybe(stream, state);
+  }
+}
+
+function onwriteStateUpdate(state) {
+  state.writing = false;
+  state.writecb = null;
+  state.length -= state.writelen;
+  state.writelen = 0;
+}
+
+function onwrite(stream, er) {
+  var state = stream._writableState;
+  var sync = state.sync;
+  var cb = state.writecb;
+
+  onwriteStateUpdate(state);
+
+  if (er) onwriteError(stream, state, sync, er, cb);else {
+    // Check if we're actually ready to finish, but don't emit yet
+    var finished = needFinish(state);
+
+    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
+      clearBuffer(stream, state);
+    }
+
+    if (sync) {
+      /*<replacement>*/
+      asyncWrite(afterWrite, stream, state, finished, cb);
+      /*</replacement>*/
+    } else {
+      afterWrite(stream, state, finished, cb);
+    }
+  }
+}
+
+function afterWrite(stream, state, finished, cb) {
+  if (!finished) onwriteDrain(stream, state);
+  state.pendingcb--;
+  cb();
+  finishMaybe(stream, state);
+}
+
+// Must force callback to be called on nextTick, so that we don't
+// emit 'drain' before the write() consumer gets the 'false' return
+// value, and has a chance to attach a 'drain' listener.
+function onwriteDrain(stream, state) {
+  if (state.length === 0 && state.needDrain) {
+    state.needDrain = false;
+    stream.emit('drain');
+  }
+}
+
+// if there's something in the buffer waiting, then process it
+function clearBuffer(stream, state) {
+  state.bufferProcessing = true;
+  var entry = state.bufferedRequest;
+
+  if (stream._writev && entry && entry.next) {
+    // Fast case, write everything using _writev()
+    var l = state.bufferedRequestCount;
+    var buffer = new Array(l);
+    var holder = state.corkedRequestsFree;
+    holder.entry = entry;
+
+    var count = 0;
+    var allBuffers = true;
+    while (entry) {
+      buffer[count] = entry;
+      if (!entry.isBuf) allBuffers = false;
+      entry = entry.next;
+      count += 1;
+    }
+    buffer.allBuffers = allBuffers;
+
+    doWrite(stream, state, true, state.length, buffer, '', holder.finish);
+
+    // doWrite is almost always async, defer these to save a bit of time
+    // as the hot path ends with doWrite
+    state.pendingcb++;
+    state.lastBufferedRequest = null;
+    if (holder.next) {
+      state.corkedRequestsFree = holder.next;
+      holder.next = null;
+    } else {
+      state.corkedRequestsFree = new CorkedRequest(state);
+    }
+    state.bufferedRequestCount = 0;
+  } else {
+    // Slow case, write chunks one-by-one
+    while (entry) {
+      var chunk = entry.chunk;
+      var encoding = entry.encoding;
+      var cb = entry.callback;
+      var len = state.objectMode ? 1 : chunk.length;
+
+      doWrite(stream, state, false, len, chunk, encoding, cb);
+      entry = entry.next;
+      state.bufferedRequestCount--;
+      // if we didn't call the onwrite immediately, then
+      // it means that we need to wait until it does.
+      // also, that means that the chunk and cb are currently
+      // being processed, so move the buffer counter past them.
+      if (state.writing) {
+        break;
+      }
+    }
+
+    if (entry === null) state.lastBufferedRequest = null;
+  }
+
+  state.bufferedRequest = entry;
+  state.bufferProcessing = false;
+}
+
+Writable.prototype._write = function (chunk, encoding, cb) {
+  cb(new Error('_write() is not implemented'));
+};
+
+Writable.prototype._writev = null;
+
+Writable.prototype.end = function (chunk, encoding, cb) {
+  var state = this._writableState;
+
+  if (typeof chunk === 'function') {
+    cb = chunk;
+    chunk = null;
+    encoding = null;
+  } else if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+
+  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding);
+
+  // .end() fully uncorks
+  if (state.corked) {
+    state.corked = 1;
+    this.uncork();
+  }
+
+  // ignore unnecessary end() calls.
+  if (!state.ending) endWritable(this, state, cb);
+};
+
+function needFinish(state) {
+  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
+}
+function callFinal(stream, state) {
+  stream._final(function (err) {
+    state.pendingcb--;
+    if (err) {
+      stream.emit('error', err);
+    }
+    state.prefinished = true;
+    stream.emit('prefinish');
+    finishMaybe(stream, state);
+  });
+}
+function prefinish(stream, state) {
+  if (!state.prefinished && !state.finalCalled) {
+    if (typeof stream._final === 'function') {
+      state.pendingcb++;
+      state.finalCalled = true;
+      pna.nextTick(callFinal, stream, state);
+    } else {
+      state.prefinished = true;
+      stream.emit('prefinish');
+    }
+  }
+}
+
+function finishMaybe(stream, state) {
+  var need = needFinish(state);
+  if (need) {
+    prefinish(stream, state);
+    if (state.pendingcb === 0) {
+      state.finished = true;
+      stream.emit('finish');
+    }
+  }
+  return need;
+}
+
+function endWritable(stream, state, cb) {
+  state.ending = true;
+  finishMaybe(stream, state);
+  if (cb) {
+    if (state.finished) pna.nextTick(cb);else stream.once('finish', cb);
+  }
+  state.ended = true;
+  stream.writable = false;
+}
+
+function onCorkedFinish(corkReq, state, err) {
+  var entry = corkReq.entry;
+  corkReq.entry = null;
+  while (entry) {
+    var cb = entry.callback;
+    state.pendingcb--;
+    cb(err);
+    entry = entry.next;
+  }
+
+  // reuse the free corkReq.
+  state.corkedRequestsFree.next = corkReq;
+}
+
+Object.defineProperty(Writable.prototype, 'destroyed', {
+  get: function () {
+    if (this._writableState === undefined) {
+      return false;
+    }
+    return this._writableState.destroyed;
+  },
+  set: function (value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._writableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._writableState.destroyed = value;
+  }
+});
+
+Writable.prototype.destroy = destroyImpl.destroy;
+Writable.prototype._undestroy = destroyImpl.undestroy;
+Writable.prototype._destroy = function (err, cb) {
+  this.end();
+  cb(err);
+};
\ No newline at end of file
diff --git a/server/node_modules/readable-stream/lib/internal/streams/BufferList.js b/server/node_modules/readable-stream/lib/internal/streams/BufferList.js
new file mode 100644
index 0000000..5e08097
--- /dev/null
+++ b/server/node_modules/readable-stream/lib/internal/streams/BufferList.js
@@ -0,0 +1,78 @@
+'use strict';
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+var Buffer = require('safe-buffer').Buffer;
+var util = require('util');
+
+function copyBuffer(src, target, offset) {
+  src.copy(target, offset);
+}
+
+module.exports = function () {
+  function BufferList() {
+    _classCallCheck(this, BufferList);
+
+    this.head = null;
+    this.tail = null;
+    this.length = 0;
+  }
+
+  BufferList.prototype.push = function push(v) {
+    var entry = { data: v, next: null };
+    if (this.length > 0) this.tail.next = entry;else this.head = entry;
+    this.tail = entry;
+    ++this.length;
+  };
+
+  BufferList.prototype.unshift = function unshift(v) {
+    var entry = { data: v, next: this.head };
+    if (this.length === 0) this.tail = entry;
+    this.head = entry;
+    ++this.length;
+  };
+
+  BufferList.prototype.shift = function shift() {
+    if (this.length === 0) return;
+    var ret = this.head.data;
+    if (this.length === 1) this.head = this.tail = null;else this.head = this.head.next;
+    --this.length;
+    return ret;
+  };
+
+  BufferList.prototype.clear = function clear() {
+    this.head = this.tail = null;
+    this.length = 0;
+  };
+
+  BufferList.prototype.join = function join(s) {
+    if (this.length === 0) return '';
+    var p = this.head;
+    var ret = '' + p.data;
+    while (p = p.next) {
+      ret += s + p.data;
+    }return ret;
+  };
+
+  BufferList.prototype.concat = function concat(n) {
+    if (this.length === 0) return Buffer.alloc(0);
+    var ret = Buffer.allocUnsafe(n >>> 0);
+    var p = this.head;
+    var i = 0;
+    while (p) {
+      copyBuffer(p.data, ret, i);
+      i += p.data.length;
+      p = p.next;
+    }
+    return ret;
+  };
+
+  return BufferList;
+}();
+
+if (util && util.inspect && util.inspect.custom) {
+  module.exports.prototype[util.inspect.custom] = function () {
+    var obj = util.inspect({ length: this.length });
+    return this.constructor.name + ' ' + obj;
+  };
+}
\ No newline at end of file
diff --git a/server/node_modules/readable-stream/lib/internal/streams/destroy.js b/server/node_modules/readable-stream/lib/internal/streams/destroy.js
new file mode 100644
index 0000000..85a8214
--- /dev/null
+++ b/server/node_modules/readable-stream/lib/internal/streams/destroy.js
@@ -0,0 +1,84 @@
+'use strict';
+
+/*<replacement>*/
+
+var pna = require('process-nextick-args');
+/*</replacement>*/
+
+// undocumented cb() API, needed for core, not for public API
+function destroy(err, cb) {
+  var _this = this;
+
+  var readableDestroyed = this._readableState && this._readableState.destroyed;
+  var writableDestroyed = this._writableState && this._writableState.destroyed;
+
+  if (readableDestroyed || writableDestroyed) {
+    if (cb) {
+      cb(err);
+    } else if (err) {
+      if (!this._writableState) {
+        pna.nextTick(emitErrorNT, this, err);
+      } else if (!this._writableState.errorEmitted) {
+        this._writableState.errorEmitted = true;
+        pna.nextTick(emitErrorNT, this, err);
+      }
+    }
+
+    return this;
+  }
+
+  // we set destroyed to true before firing error callbacks in order
+  // to make it re-entrance safe in case destroy() is called within callbacks
+
+  if (this._readableState) {
+    this._readableState.destroyed = true;
+  }
+
+  // if this is a duplex stream mark the writable part as destroyed as well
+  if (this._writableState) {
+    this._writableState.destroyed = true;
+  }
+
+  this._destroy(err || null, function (err) {
+    if (!cb && err) {
+      if (!_this._writableState) {
+        pna.nextTick(emitErrorNT, _this, err);
+      } else if (!_this._writableState.errorEmitted) {
+        _this._writableState.errorEmitted = true;
+        pna.nextTick(emitErrorNT, _this, err);
+      }
+    } else if (cb) {
+      cb(err);
+    }
+  });
+
+  return this;
+}
+
+function undestroy() {
+  if (this._readableState) {
+    this._readableState.destroyed = false;
+    this._readableState.reading = false;
+    this._readableState.ended = false;
+    this._readableState.endEmitted = false;
+  }
+
+  if (this._writableState) {
+    this._writableState.destroyed = false;
+    this._writableState.ended = false;
+    this._writableState.ending = false;
+    this._writableState.finalCalled = false;
+    this._writableState.prefinished = false;
+    this._writableState.finished = false;
+    this._writableState.errorEmitted = false;
+  }
+}
+
+function emitErrorNT(self, err) {
+  self.emit('error', err);
+}
+
+module.exports = {
+  destroy: destroy,
+  undestroy: undestroy
+};
\ No newline at end of file
diff --git a/server/node_modules/readable-stream/lib/internal/streams/stream-browser.js b/server/node_modules/readable-stream/lib/internal/streams/stream-browser.js
new file mode 100644
index 0000000..9332a3f
--- /dev/null
+++ b/server/node_modules/readable-stream/lib/internal/streams/stream-browser.js
@@ -0,0 +1 @@
+module.exports = require('events').EventEmitter;
diff --git a/server/node_modules/readable-stream/lib/internal/streams/stream.js b/server/node_modules/readable-stream/lib/internal/streams/stream.js
new file mode 100644
index 0000000..ce2ad5b
--- /dev/null
+++ b/server/node_modules/readable-stream/lib/internal/streams/stream.js
@@ -0,0 +1 @@
+module.exports = require('stream');
diff --git a/server/node_modules/readable-stream/node_modules/safe-buffer/LICENSE b/server/node_modules/readable-stream/node_modules/safe-buffer/LICENSE
new file mode 100644
index 0000000..0c068ce
--- /dev/null
+++ b/server/node_modules/readable-stream/node_modules/safe-buffer/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Feross Aboukhadijeh
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/readable-stream/node_modules/safe-buffer/README.md b/server/node_modules/readable-stream/node_modules/safe-buffer/README.md
new file mode 100644
index 0000000..e9a81af
--- /dev/null
+++ b/server/node_modules/readable-stream/node_modules/safe-buffer/README.md
@@ -0,0 +1,584 @@
+# safe-buffer [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![downloads][downloads-image]][downloads-url] [![javascript style guide][standard-image]][standard-url]
+
+[travis-image]: https://img.shields.io/travis/feross/safe-buffer/master.svg
+[travis-url]: https://travis-ci.org/feross/safe-buffer
+[npm-image]: https://img.shields.io/npm/v/safe-buffer.svg
+[npm-url]: https://npmjs.org/package/safe-buffer
+[downloads-image]: https://img.shields.io/npm/dm/safe-buffer.svg
+[downloads-url]: https://npmjs.org/package/safe-buffer
+[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
+[standard-url]: https://standardjs.com
+
+#### Safer Node.js Buffer API
+
+**Use the new Node.js Buffer APIs (`Buffer.from`, `Buffer.alloc`,
+`Buffer.allocUnsafe`, `Buffer.allocUnsafeSlow`) in all versions of Node.js.**
+
+**Uses the built-in implementation when available.**
+
+## install
+
+```
+npm install safe-buffer
+```
+
+## usage
+
+The goal of this package is to provide a safe replacement for the node.js `Buffer`.
+
+It's a drop-in replacement for `Buffer`. You can use it by adding one `require` line to
+the top of your node.js modules:
+
+```js
+var Buffer = require('safe-buffer').Buffer
+
+// Existing buffer code will continue to work without issues:
+
+new Buffer('hey', 'utf8')
+new Buffer([1, 2, 3], 'utf8')
+new Buffer(obj)
+new Buffer(16) // create an uninitialized buffer (potentially unsafe)
+
+// But you can use these new explicit APIs to make clear what you want:
+
+Buffer.from('hey', 'utf8') // convert from many types to a Buffer
+Buffer.alloc(16) // create a zero-filled buffer (safe)
+Buffer.allocUnsafe(16) // create an uninitialized buffer (potentially unsafe)
+```
+
+## api
+
+### Class Method: Buffer.from(array)
+
+
+* `array` {Array}
+
+Allocates a new `Buffer` using an `array` of octets.
+
+```js
+const buf = Buffer.from([0x62,0x75,0x66,0x66,0x65,0x72]);
+  // creates a new Buffer containing ASCII bytes
+  // ['b','u','f','f','e','r']
+```
+
+A `TypeError` will be thrown if `array` is not an `Array`.
+
+### Class Method: Buffer.from(arrayBuffer[, byteOffset[, length]])
+
+
+* `arrayBuffer` {ArrayBuffer} The `.buffer` property of a `TypedArray` or
+  a `new ArrayBuffer()`
+* `byteOffset` {Number} Default: `0`
+* `length` {Number} Default: `arrayBuffer.length - byteOffset`
+
+When passed a reference to the `.buffer` property of a `TypedArray` instance,
+the newly created `Buffer` will share the same allocated memory as the
+TypedArray.
+
+```js
+const arr = new Uint16Array(2);
+arr[0] = 5000;
+arr[1] = 4000;
+
+const buf = Buffer.from(arr.buffer); // shares the memory with arr;
+
+console.log(buf);
+  // Prints: <Buffer 88 13 a0 0f>
+
+// changing the TypedArray changes the Buffer also
+arr[1] = 6000;
+
+console.log(buf);
+  // Prints: <Buffer 88 13 70 17>
+```
+
+The optional `byteOffset` and `length` arguments specify a memory range within
+the `arrayBuffer` that will be shared by the `Buffer`.
+
+```js
+const ab = new ArrayBuffer(10);
+const buf = Buffer.from(ab, 0, 2);
+console.log(buf.length);
+  // Prints: 2
+```
+
+A `TypeError` will be thrown if `arrayBuffer` is not an `ArrayBuffer`.
+
+### Class Method: Buffer.from(buffer)
+
+
+* `buffer` {Buffer}
+
+Copies the passed `buffer` data onto a new `Buffer` instance.
+
+```js
+const buf1 = Buffer.from('buffer');
+const buf2 = Buffer.from(buf1);
+
+buf1[0] = 0x61;
+console.log(buf1.toString());
+  // 'auffer'
+console.log(buf2.toString());
+  // 'buffer' (copy is not changed)
+```
+
+A `TypeError` will be thrown if `buffer` is not a `Buffer`.
+
+### Class Method: Buffer.from(str[, encoding])
+
+
+* `str` {String} String to encode.
+* `encoding` {String} Encoding to use, Default: `'utf8'`
+
+Creates a new `Buffer` containing the given JavaScript string `str`. If
+provided, the `encoding` parameter identifies the character encoding.
+If not provided, `encoding` defaults to `'utf8'`.
+
+```js
+const buf1 = Buffer.from('this is a tést');
+console.log(buf1.toString());
+  // prints: this is a tést
+console.log(buf1.toString('ascii'));
+  // prints: this is a tC)st
+
+const buf2 = Buffer.from('7468697320697320612074c3a97374', 'hex');
+console.log(buf2.toString());
+  // prints: this is a tést
+```
+
+A `TypeError` will be thrown if `str` is not a string.
+
+### Class Method: Buffer.alloc(size[, fill[, encoding]])
+
+
+* `size` {Number}
+* `fill` {Value} Default: `undefined`
+* `encoding` {String} Default: `utf8`
+
+Allocates a new `Buffer` of `size` bytes. If `fill` is `undefined`, the
+`Buffer` will be *zero-filled*.
+
+```js
+const buf = Buffer.alloc(5);
+console.log(buf);
+  // <Buffer 00 00 00 00 00>
+```
+
+The `size` must be less than or equal to the value of
+`require('buffer').kMaxLength` (on 64-bit architectures, `kMaxLength` is
+`(2^31)-1`). Otherwise, a [`RangeError`][] is thrown. A zero-length Buffer will
+be created if a `size` less than or equal to 0 is specified.
+
+If `fill` is specified, the allocated `Buffer` will be initialized by calling
+`buf.fill(fill)`. See [`buf.fill()`][] for more information.
+
+```js
+const buf = Buffer.alloc(5, 'a');
+console.log(buf);
+  // <Buffer 61 61 61 61 61>
+```
+
+If both `fill` and `encoding` are specified, the allocated `Buffer` will be
+initialized by calling `buf.fill(fill, encoding)`. For example:
+
+```js
+const buf = Buffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');
+console.log(buf);
+  // <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64>
+```
+
+Calling `Buffer.alloc(size)` can be significantly slower than the alternative
+`Buffer.allocUnsafe(size)` but ensures that the newly created `Buffer` instance
+contents will *never contain sensitive data*.
+
+A `TypeError` will be thrown if `size` is not a number.
+
+### Class Method: Buffer.allocUnsafe(size)
+
+
+* `size` {Number}
+
+Allocates a new *non-zero-filled* `Buffer` of `size` bytes.  The `size` must
+be less than or equal to the value of `require('buffer').kMaxLength` (on 64-bit
+architectures, `kMaxLength` is `(2^31)-1`). Otherwise, a [`RangeError`][] is
+thrown. A zero-length Buffer will be created if a `size` less than or equal to
+0 is specified.
+
+The underlying memory for `Buffer` instances created in this way is *not
+initialized*. The contents of the newly created `Buffer` are unknown and
+*may contain sensitive data*. Use [`buf.fill(0)`][] to initialize such
+`Buffer` instances to zeroes.
+
+```js
+const buf = Buffer.allocUnsafe(5);
+console.log(buf);
+  // <Buffer 78 e0 82 02 01>
+  // (octets will be different, every time)
+buf.fill(0);
+console.log(buf);
+  // <Buffer 00 00 00 00 00>
+```
+
+A `TypeError` will be thrown if `size` is not a number.
+
+Note that the `Buffer` module pre-allocates an internal `Buffer` instance of
+size `Buffer.poolSize` that is used as a pool for the fast allocation of new
+`Buffer` instances created using `Buffer.allocUnsafe(size)` (and the deprecated
+`new Buffer(size)` constructor) only when `size` is less than or equal to
+`Buffer.poolSize >> 1` (floor of `Buffer.poolSize` divided by two). The default
+value of `Buffer.poolSize` is `8192` but can be modified.
+
+Use of this pre-allocated internal memory pool is a key difference between
+calling `Buffer.alloc(size, fill)` vs. `Buffer.allocUnsafe(size).fill(fill)`.
+Specifically, `Buffer.alloc(size, fill)` will *never* use the internal Buffer
+pool, while `Buffer.allocUnsafe(size).fill(fill)` *will* use the internal
+Buffer pool if `size` is less than or equal to half `Buffer.poolSize`. The
+difference is subtle but can be important when an application requires the
+additional performance that `Buffer.allocUnsafe(size)` provides.
+
+### Class Method: Buffer.allocUnsafeSlow(size)
+
+
+* `size` {Number}
+
+Allocates a new *non-zero-filled* and non-pooled `Buffer` of `size` bytes.  The
+`size` must be less than or equal to the value of
+`require('buffer').kMaxLength` (on 64-bit architectures, `kMaxLength` is
+`(2^31)-1`). Otherwise, a [`RangeError`][] is thrown. A zero-length Buffer will
+be created if a `size` less than or equal to 0 is specified.
+
+The underlying memory for `Buffer` instances created in this way is *not
+initialized*. The contents of the newly created `Buffer` are unknown and
+*may contain sensitive data*. Use [`buf.fill(0)`][] to initialize such
+`Buffer` instances to zeroes.
+
+When using `Buffer.allocUnsafe()` to allocate new `Buffer` instances,
+allocations under 4KB are, by default, sliced from a single pre-allocated
+`Buffer`. This allows applications to avoid the garbage collection overhead of
+creating many individually allocated Buffers. This approach improves both
+performance and memory usage by eliminating the need to track and cleanup as
+many `Persistent` objects.
+
+However, in the case where a developer may need to retain a small chunk of
+memory from a pool for an indeterminate amount of time, it may be appropriate
+to create an un-pooled Buffer instance using `Buffer.allocUnsafeSlow()` then
+copy out the relevant bits.
+
+```js
+// need to keep around a few small chunks of memory
+const store = [];
+
+socket.on('readable', () => {
+  const data = socket.read();
+  // allocate for retained data
+  const sb = Buffer.allocUnsafeSlow(10);
+  // copy the data into the new allocation
+  data.copy(sb, 0, 0, 10);
+  store.push(sb);
+});
+```
+
+Use of `Buffer.allocUnsafeSlow()` should be used only as a last resort *after*
+a developer has observed undue memory retention in their applications.
+
+A `TypeError` will be thrown if `size` is not a number.
+
+### All the Rest
+
+The rest of the `Buffer` API is exactly the same as in node.js.
+[See the docs](https://nodejs.org/api/buffer.html).
+
+
+## Related links
+
+- [Node.js issue: Buffer(number) is unsafe](https://github.com/nodejs/node/issues/4660)
+- [Node.js Enhancement Proposal: Buffer.from/Buffer.alloc/Buffer.zalloc/Buffer() soft-deprecate](https://github.com/nodejs/node-eps/pull/4)
+
+## Why is `Buffer` unsafe?
+
+Today, the node.js `Buffer` constructor is overloaded to handle many different argument
+types like `String`, `Array`, `Object`, `TypedArrayView` (`Uint8Array`, etc.),
+`ArrayBuffer`, and also `Number`.
+
+The API is optimized for convenience: you can throw any type at it, and it will try to do
+what you want.
+
+Because the Buffer constructor is so powerful, you often see code like this:
+
+```js
+// Convert UTF-8 strings to hex
+function toHex (str) {
+  return new Buffer(str).toString('hex')
+}
+```
+
+***But what happens if `toHex` is called with a `Number` argument?***
+
+### Remote Memory Disclosure
+
+If an attacker can make your program call the `Buffer` constructor with a `Number`
+argument, then they can make it allocate uninitialized memory from the node.js process.
+This could potentially disclose TLS private keys, user data, or database passwords.
+
+When the `Buffer` constructor is passed a `Number` argument, it returns an
+**UNINITIALIZED** block of memory of the specified `size`. When you create a `Buffer` like
+this, you **MUST** overwrite the contents before returning it to the user.
+
+From the [node.js docs](https://nodejs.org/api/buffer.html#buffer_new_buffer_size):
+
+> `new Buffer(size)`
+>
+> - `size` Number
+>
+> The underlying memory for `Buffer` instances created in this way is not initialized.
+> **The contents of a newly created `Buffer` are unknown and could contain sensitive
+> data.** Use `buf.fill(0)` to initialize a Buffer to zeroes.
+
+(Emphasis our own.)
+
+Whenever the programmer intended to create an uninitialized `Buffer` you often see code
+like this:
+
+```js
+var buf = new Buffer(16)
+
+// Immediately overwrite the uninitialized buffer with data from another buffer
+for (var i = 0; i < buf.length; i++) {
+  buf[i] = otherBuf[i]
+}
+```
+
+
+### Would this ever be a problem in real code?
+
+Yes. It's surprisingly common to forget to check the type of your variables in a
+dynamically-typed language like JavaScript.
+
+Usually the consequences of assuming the wrong type is that your program crashes with an
+uncaught exception. But the failure mode for forgetting to check the type of arguments to
+the `Buffer` constructor is more catastrophic.
+
+Here's an example of a vulnerable service that takes a JSON payload and converts it to
+hex:
+
+```js
+// Take a JSON payload {str: "some string"} and convert it to hex
+var server = http.createServer(function (req, res) {
+  var data = ''
+  req.setEncoding('utf8')
+  req.on('data', function (chunk) {
+    data += chunk
+  })
+  req.on('end', function () {
+    var body = JSON.parse(data)
+    res.end(new Buffer(body.str).toString('hex'))
+  })
+})
+
+server.listen(8080)
+```
+
+In this example, an http client just has to send:
+
+```json
+{
+  "str": 1000
+}
+```
+
+and it will get back 1,000 bytes of uninitialized memory from the server.
+
+This is a very serious bug. It's similar in severity to the
+[the Heartbleed bug](http://heartbleed.com/) that allowed disclosure of OpenSSL process
+memory by remote attackers.
+
+
+### Which real-world packages were vulnerable?
+
+#### [`bittorrent-dht`](https://www.npmjs.com/package/bittorrent-dht)
+
+[Mathias Buus](https://github.com/mafintosh) and I
+([Feross Aboukhadijeh](http://feross.org/)) found this issue in one of our own packages,
+[`bittorrent-dht`](https://www.npmjs.com/package/bittorrent-dht). The bug would allow
+anyone on the internet to send a series of messages to a user of `bittorrent-dht` and get
+them to reveal 20 bytes at a time of uninitialized memory from the node.js process.
+
+Here's
+[the commit](https://github.com/feross/bittorrent-dht/commit/6c7da04025d5633699800a99ec3fbadf70ad35b8)
+that fixed it. We released a new fixed version, created a
+[Node Security Project disclosure](https://nodesecurity.io/advisories/68), and deprecated all
+vulnerable versions on npm so users will get a warning to upgrade to a newer version.
+
+#### [`ws`](https://www.npmjs.com/package/ws)
+
+That got us wondering if there were other vulnerable packages. Sure enough, within a short
+period of time, we found the same issue in [`ws`](https://www.npmjs.com/package/ws), the
+most popular WebSocket implementation in node.js.
+
+If certain APIs were called with `Number` parameters instead of `String` or `Buffer` as
+expected, then uninitialized server memory would be disclosed to the remote peer.
+
+These were the vulnerable methods:
+
+```js
+socket.send(number)
+socket.ping(number)
+socket.pong(number)
+```
+
+Here's a vulnerable socket server with some echo functionality:
+
+```js
+server.on('connection', function (socket) {
+  socket.on('message', function (message) {
+    message = JSON.parse(message)
+    if (message.type === 'echo') {
+      socket.send(message.data) // send back the user's message
+    }
+  })
+})
+```
+
+`socket.send(number)` called on the server, will disclose server memory.
+
+Here's [the release](https://github.com/websockets/ws/releases/tag/1.0.1) where the issue
+was fixed, with a more detailed explanation. Props to
+[Arnout Kazemier](https://github.com/3rd-Eden) for the quick fix. Here's the
+[Node Security Project disclosure](https://nodesecurity.io/advisories/67).
+
+
+### What's the solution?
+
+It's important that node.js offers a fast way to get memory otherwise performance-critical
+applications would needlessly get a lot slower.
+
+But we need a better way to *signal our intent* as programmers. **When we want
+uninitialized memory, we should request it explicitly.**
+
+Sensitive functionality should not be packed into a developer-friendly API that loosely
+accepts many different types. This type of API encourages the lazy practice of passing
+variables in without checking the type very carefully.
+
+#### A new API: `Buffer.allocUnsafe(number)`
+
+The functionality of creating buffers with uninitialized memory should be part of another
+API. We propose `Buffer.allocUnsafe(number)`. This way, it's not part of an API that
+frequently gets user input of all sorts of different types passed into it.
+
+```js
+var buf = Buffer.allocUnsafe(16) // careful, uninitialized memory!
+
+// Immediately overwrite the uninitialized buffer with data from another buffer
+for (var i = 0; i < buf.length; i++) {
+  buf[i] = otherBuf[i]
+}
+```
+
+
+### How do we fix node.js core?
+
+We sent [a PR to node.js core](https://github.com/nodejs/node/pull/4514) (merged as
+`semver-major`) which defends against one case:
+
+```js
+var str = 16
+new Buffer(str, 'utf8')
+```
+
+In this situation, it's implied that the programmer intended the first argument to be a
+string, since they passed an encoding as a second argument. Today, node.js will allocate
+uninitialized memory in the case of `new Buffer(number, encoding)`, which is probably not
+what the programmer intended.
+
+But this is only a partial solution, since if the programmer does `new Buffer(variable)`
+(without an `encoding` parameter) there's no way to know what they intended. If `variable`
+is sometimes a number, then uninitialized memory will sometimes be returned.
+
+### What's the real long-term fix?
+
+We could deprecate and remove `new Buffer(number)` and use `Buffer.allocUnsafe(number)` when
+we need uninitialized memory. But that would break 1000s of packages.
+
+~~We believe the best solution is to:~~
+
+~~1. Change `new Buffer(number)` to return safe, zeroed-out memory~~
+
+~~2. Create a new API for creating uninitialized Buffers. We propose: `Buffer.allocUnsafe(number)`~~
+
+#### Update
+
+We now support adding three new APIs:
+
+- `Buffer.from(value)` - convert from any type to a buffer
+- `Buffer.alloc(size)` - create a zero-filled buffer
+- `Buffer.allocUnsafe(size)` - create an uninitialized buffer with given size
+
+This solves the core problem that affected `ws` and `bittorrent-dht` which is
+`Buffer(variable)` getting tricked into taking a number argument.
+
+This way, existing code continues working and the impact on the npm ecosystem will be
+minimal. Over time, npm maintainers can migrate performance-critical code to use
+`Buffer.allocUnsafe(number)` instead of `new Buffer(number)`.
+
+
+### Conclusion
+
+We think there's a serious design issue with the `Buffer` API as it exists today. It
+promotes insecure software by putting high-risk functionality into a convenient API
+with friendly "developer ergonomics".
+
+This wasn't merely a theoretical exercise because we found the issue in some of the
+most popular npm packages.
+
+Fortunately, there's an easy fix that can be applied today. Use `safe-buffer` in place of
+`buffer`.
+
+```js
+var Buffer = require('safe-buffer').Buffer
+```
+
+Eventually, we hope that node.js core can switch to this new, safer behavior. We believe
+the impact on the ecosystem would be minimal since it's not a breaking change.
+Well-maintained, popular packages would be updated to use `Buffer.alloc` quickly, while
+older, insecure packages would magically become safe from this attack vector.
+
+
+## links
+
+- [Node.js PR: buffer: throw if both length and enc are passed](https://github.com/nodejs/node/pull/4514)
+- [Node Security Project disclosure for `ws`](https://nodesecurity.io/advisories/67)
+- [Node Security Project disclosure for`bittorrent-dht`](https://nodesecurity.io/advisories/68)
+
+
+## credit
+
+The original issues in `bittorrent-dht`
+([disclosure](https://nodesecurity.io/advisories/68)) and
+`ws` ([disclosure](https://nodesecurity.io/advisories/67)) were discovered by
+[Mathias Buus](https://github.com/mafintosh) and
+[Feross Aboukhadijeh](http://feross.org/).
+
+Thanks to [Adam Baldwin](https://github.com/evilpacket) for helping disclose these issues
+and for his work running the [Node Security Project](https://nodesecurity.io/).
+
+Thanks to [John Hiesey](https://github.com/jhiesey) for proofreading this README and
+auditing the code.
+
+
+## license
+
+MIT. Copyright (C) [Feross Aboukhadijeh](http://feross.org)
diff --git a/server/node_modules/readable-stream/node_modules/safe-buffer/index.d.ts b/server/node_modules/readable-stream/node_modules/safe-buffer/index.d.ts
new file mode 100644
index 0000000..e9fed80
--- /dev/null
+++ b/server/node_modules/readable-stream/node_modules/safe-buffer/index.d.ts
@@ -0,0 +1,187 @@
+declare module "safe-buffer" {
+  export class Buffer {
+    length: number
+    write(string: string, offset?: number, length?: number, encoding?: string): number;
+    toString(encoding?: string, start?: number, end?: number): string;
+    toJSON(): { type: 'Buffer', data: any[] };
+    equals(otherBuffer: Buffer): boolean;
+    compare(otherBuffer: Buffer, targetStart?: number, targetEnd?: number, sourceStart?: number, sourceEnd?: number): number;
+    copy(targetBuffer: Buffer, targetStart?: number, sourceStart?: number, sourceEnd?: number): number;
+    slice(start?: number, end?: number): Buffer;
+    writeUIntLE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeUIntBE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeIntLE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeIntBE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    readUIntLE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readUIntBE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readIntLE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readIntBE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readUInt8(offset: number, noAssert?: boolean): number;
+    readUInt16LE(offset: number, noAssert?: boolean): number;
+    readUInt16BE(offset: number, noAssert?: boolean): number;
+    readUInt32LE(offset: number, noAssert?: boolean): number;
+    readUInt32BE(offset: number, noAssert?: boolean): number;
+    readInt8(offset: number, noAssert?: boolean): number;
+    readInt16LE(offset: number, noAssert?: boolean): number;
+    readInt16BE(offset: number, noAssert?: boolean): number;
+    readInt32LE(offset: number, noAssert?: boolean): number;
+    readInt32BE(offset: number, noAssert?: boolean): number;
+    readFloatLE(offset: number, noAssert?: boolean): number;
+    readFloatBE(offset: number, noAssert?: boolean): number;
+    readDoubleLE(offset: number, noAssert?: boolean): number;
+    readDoubleBE(offset: number, noAssert?: boolean): number;
+    swap16(): Buffer;
+    swap32(): Buffer;
+    swap64(): Buffer;
+    writeUInt8(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt16LE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt16BE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt32LE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt32BE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt8(value: number, offset: number, noAssert?: boolean): number;
+    writeInt16LE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt16BE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt32LE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt32BE(value: number, offset: number, noAssert?: boolean): number;
+    writeFloatLE(value: number, offset: number, noAssert?: boolean): number;
+    writeFloatBE(value: number, offset: number, noAssert?: boolean): number;
+    writeDoubleLE(value: number, offset: number, noAssert?: boolean): number;
+    writeDoubleBE(value: number, offset: number, noAssert?: boolean): number;
+    fill(value: any, offset?: number, end?: number): this;
+    indexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
+    lastIndexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
+    includes(value: string | number | Buffer, byteOffset?: number, encoding?: string): boolean;
+
+    /**
+     * Allocates a new buffer containing the given {str}.
+     *
+     * @param str String to store in buffer.
+     * @param encoding encoding to use, optional.  Default is 'utf8'
+     */
+     constructor (str: string, encoding?: string);
+    /**
+     * Allocates a new buffer of {size} octets.
+     *
+     * @param size count of octets to allocate.
+     */
+    constructor (size: number);
+    /**
+     * Allocates a new buffer containing the given {array} of octets.
+     *
+     * @param array The octets to store.
+     */
+    constructor (array: Uint8Array);
+    /**
+     * Produces a Buffer backed by the same allocated memory as
+     * the given {ArrayBuffer}.
+     *
+     *
+     * @param arrayBuffer The ArrayBuffer with which to share memory.
+     */
+    constructor (arrayBuffer: ArrayBuffer);
+    /**
+     * Allocates a new buffer containing the given {array} of octets.
+     *
+     * @param array The octets to store.
+     */
+    constructor (array: any[]);
+    /**
+     * Copies the passed {buffer} data onto a new {Buffer} instance.
+     *
+     * @param buffer The buffer to copy.
+     */
+    constructor (buffer: Buffer);
+    prototype: Buffer;
+    /**
+     * Allocates a new Buffer using an {array} of octets.
+     *
+     * @param array
+     */
+    static from(array: any[]): Buffer;
+    /**
+     * When passed a reference to the .buffer property of a TypedArray instance,
+     * the newly created Buffer will share the same allocated memory as the TypedArray.
+     * The optional {byteOffset} and {length} arguments specify a memory range
+     * within the {arrayBuffer} that will be shared by the Buffer.
+     *
+     * @param arrayBuffer The .buffer property of a TypedArray or a new ArrayBuffer()
+     * @param byteOffset
+     * @param length
+     */
+    static from(arrayBuffer: ArrayBuffer, byteOffset?: number, length?: number): Buffer;
+    /**
+     * Copies the passed {buffer} data onto a new Buffer instance.
+     *
+     * @param buffer
+     */
+    static from(buffer: Buffer): Buffer;
+    /**
+     * Creates a new Buffer containing the given JavaScript string {str}.
+     * If provided, the {encoding} parameter identifies the character encoding.
+     * If not provided, {encoding} defaults to 'utf8'.
+     *
+     * @param str
+     */
+    static from(str: string, encoding?: string): Buffer;
+    /**
+     * Returns true if {obj} is a Buffer
+     *
+     * @param obj object to test.
+     */
+    static isBuffer(obj: any): obj is Buffer;
+    /**
+     * Returns true if {encoding} is a valid encoding argument.
+     * Valid string encodings in Node 0.12: 'ascii'|'utf8'|'utf16le'|'ucs2'(alias of 'utf16le')|'base64'|'binary'(deprecated)|'hex'
+     *
+     * @param encoding string to test.
+     */
+    static isEncoding(encoding: string): boolean;
+    /**
+     * Gives the actual byte length of a string. encoding defaults to 'utf8'.
+     * This is not the same as String.prototype.length since that returns the number of characters in a string.
+     *
+     * @param string string to test.
+     * @param encoding encoding used to evaluate (defaults to 'utf8')
+     */
+    static byteLength(string: string, encoding?: string): number;
+    /**
+     * Returns a buffer which is the result of concatenating all the buffers in the list together.
+     *
+     * If the list has no items, or if the totalLength is 0, then it returns a zero-length buffer.
+     * If the list has exactly one item, then the first item of the list is returned.
+     * If the list has more than one item, then a new Buffer is created.
+     *
+     * @param list An array of Buffer objects to concatenate
+     * @param totalLength Total length of the buffers when concatenated.
+     *   If totalLength is not provided, it is read from the buffers in the list. However, this adds an additional loop to the function, so it is faster to provide the length explicitly.
+     */
+    static concat(list: Buffer[], totalLength?: number): Buffer;
+    /**
+     * The same as buf1.compare(buf2).
+     */
+    static compare(buf1: Buffer, buf2: Buffer): number;
+    /**
+     * Allocates a new buffer of {size} octets.
+     *
+     * @param size count of octets to allocate.
+     * @param fill if specified, buffer will be initialized by calling buf.fill(fill).
+     *    If parameter is omitted, buffer will be filled with zeros.
+     * @param encoding encoding used for call to buf.fill while initalizing
+     */
+    static alloc(size: number, fill?: string | Buffer | number, encoding?: string): Buffer;
+    /**
+     * Allocates a new buffer of {size} octets, leaving memory not initialized, so the contents
+     * of the newly created Buffer are unknown and may contain sensitive data.
+     *
+     * @param size count of octets to allocate
+     */
+    static allocUnsafe(size: number): Buffer;
+    /**
+     * Allocates a new non-pooled buffer of {size} octets, leaving memory not initialized, so the contents
+     * of the newly created Buffer are unknown and may contain sensitive data.
+     *
+     * @param size count of octets to allocate
+     */
+    static allocUnsafeSlow(size: number): Buffer;
+  }
+}
\ No newline at end of file
diff --git a/server/node_modules/readable-stream/node_modules/safe-buffer/index.js b/server/node_modules/readable-stream/node_modules/safe-buffer/index.js
new file mode 100644
index 0000000..22438da
--- /dev/null
+++ b/server/node_modules/readable-stream/node_modules/safe-buffer/index.js
@@ -0,0 +1,62 @@
+/* eslint-disable node/no-deprecated-api */
+var buffer = require('buffer')
+var Buffer = buffer.Buffer
+
+// alternative to using Object.keys for old browsers
+function copyProps (src, dst) {
+  for (var key in src) {
+    dst[key] = src[key]
+  }
+}
+if (Buffer.from && Buffer.alloc && Buffer.allocUnsafe && Buffer.allocUnsafeSlow) {
+  module.exports = buffer
+} else {
+  // Copy properties from require('buffer')
+  copyProps(buffer, exports)
+  exports.Buffer = SafeBuffer
+}
+
+function SafeBuffer (arg, encodingOrOffset, length) {
+  return Buffer(arg, encodingOrOffset, length)
+}
+
+// Copy static methods from Buffer
+copyProps(Buffer, SafeBuffer)
+
+SafeBuffer.from = function (arg, encodingOrOffset, length) {
+  if (typeof arg === 'number') {
+    throw new TypeError('Argument must not be a number')
+  }
+  return Buffer(arg, encodingOrOffset, length)
+}
+
+SafeBuffer.alloc = function (size, fill, encoding) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  var buf = Buffer(size)
+  if (fill !== undefined) {
+    if (typeof encoding === 'string') {
+      buf.fill(fill, encoding)
+    } else {
+      buf.fill(fill)
+    }
+  } else {
+    buf.fill(0)
+  }
+  return buf
+}
+
+SafeBuffer.allocUnsafe = function (size) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  return Buffer(size)
+}
+
+SafeBuffer.allocUnsafeSlow = function (size) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  return buffer.SlowBuffer(size)
+}
diff --git a/server/node_modules/readable-stream/node_modules/safe-buffer/package.json b/server/node_modules/readable-stream/node_modules/safe-buffer/package.json
new file mode 100644
index 0000000..623fbc3
--- /dev/null
+++ b/server/node_modules/readable-stream/node_modules/safe-buffer/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "safe-buffer",
+  "description": "Safer Node.js Buffer API",
+  "version": "5.1.2",
+  "author": {
+    "name": "Feross Aboukhadijeh",
+    "email": "feross@feross.org",
+    "url": "http://feross.org"
+  },
+  "bugs": {
+    "url": "https://github.com/feross/safe-buffer/issues"
+  },
+  "devDependencies": {
+    "standard": "*",
+    "tape": "^4.0.0"
+  },
+  "homepage": "https://github.com/feross/safe-buffer",
+  "keywords": [
+    "buffer",
+    "buffer allocate",
+    "node security",
+    "safe",
+    "safe-buffer",
+    "security",
+    "uninitialized"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/feross/safe-buffer.git"
+  },
+  "scripts": {
+    "test": "standard && tape test/*.js"
+  }
+}
diff --git a/server/node_modules/readable-stream/package.json b/server/node_modules/readable-stream/package.json
new file mode 100644
index 0000000..514c178
--- /dev/null
+++ b/server/node_modules/readable-stream/package.json
@@ -0,0 +1,52 @@
+{
+  "name": "readable-stream",
+  "version": "2.3.8",
+  "description": "Streams3, a user-land copy of the stream library from Node.js",
+  "main": "readable.js",
+  "dependencies": {
+    "core-util-is": "~1.0.0",
+    "inherits": "~2.0.3",
+    "isarray": "~1.0.0",
+    "process-nextick-args": "~2.0.0",
+    "safe-buffer": "~5.1.1",
+    "string_decoder": "~1.1.1",
+    "util-deprecate": "~1.0.1"
+  },
+  "devDependencies": {
+    "assert": "^1.4.0",
+    "babel-polyfill": "^6.9.1",
+    "buffer": "^4.9.0",
+    "lolex": "^2.3.2",
+    "nyc": "^6.4.0",
+    "tap": "^0.7.0",
+    "tape": "^4.8.0"
+  },
+  "scripts": {
+    "test": "tap test/parallel/*.js test/ours/*.js && node test/verify-dependencies.js",
+    "ci": "tap test/parallel/*.js test/ours/*.js --tap | tee test.tap && node test/verify-dependencies.js",
+    "cover": "nyc npm test",
+    "report": "nyc report --reporter=lcov"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/nodejs/readable-stream"
+  },
+  "keywords": [
+    "readable",
+    "stream",
+    "pipe"
+  ],
+  "browser": {
+    "util": false,
+    "./readable.js": "./readable-browser.js",
+    "./writable.js": "./writable-browser.js",
+    "./duplex.js": "./duplex-browser.js",
+    "./lib/internal/streams/stream.js": "./lib/internal/streams/stream-browser.js"
+  },
+  "nyc": {
+    "include": [
+      "lib/**.js"
+    ]
+  },
+  "license": "MIT"
+}
diff --git a/server/node_modules/readable-stream/passthrough.js b/server/node_modules/readable-stream/passthrough.js
new file mode 100644
index 0000000..ffd791d
--- /dev/null
+++ b/server/node_modules/readable-stream/passthrough.js
@@ -0,0 +1 @@
+module.exports = require('./readable').PassThrough
diff --git a/server/node_modules/readable-stream/readable-browser.js b/server/node_modules/readable-stream/readable-browser.js
new file mode 100644
index 0000000..e503725
--- /dev/null
+++ b/server/node_modules/readable-stream/readable-browser.js
@@ -0,0 +1,7 @@
+exports = module.exports = require('./lib/_stream_readable.js');
+exports.Stream = exports;
+exports.Readable = exports;
+exports.Writable = require('./lib/_stream_writable.js');
+exports.Duplex = require('./lib/_stream_duplex.js');
+exports.Transform = require('./lib/_stream_transform.js');
+exports.PassThrough = require('./lib/_stream_passthrough.js');
diff --git a/server/node_modules/readable-stream/readable.js b/server/node_modules/readable-stream/readable.js
new file mode 100644
index 0000000..ec89ec5
--- /dev/null
+++ b/server/node_modules/readable-stream/readable.js
@@ -0,0 +1,19 @@
+var Stream = require('stream');
+if (process.env.READABLE_STREAM === 'disable' && Stream) {
+  module.exports = Stream;
+  exports = module.exports = Stream.Readable;
+  exports.Readable = Stream.Readable;
+  exports.Writable = Stream.Writable;
+  exports.Duplex = Stream.Duplex;
+  exports.Transform = Stream.Transform;
+  exports.PassThrough = Stream.PassThrough;
+  exports.Stream = Stream;
+} else {
+  exports = module.exports = require('./lib/_stream_readable.js');
+  exports.Stream = Stream || exports;
+  exports.Readable = exports;
+  exports.Writable = require('./lib/_stream_writable.js');
+  exports.Duplex = require('./lib/_stream_duplex.js');
+  exports.Transform = require('./lib/_stream_transform.js');
+  exports.PassThrough = require('./lib/_stream_passthrough.js');
+}
diff --git a/server/node_modules/readable-stream/transform.js b/server/node_modules/readable-stream/transform.js
new file mode 100644
index 0000000..b1baba2
--- /dev/null
+++ b/server/node_modules/readable-stream/transform.js
@@ -0,0 +1 @@
+module.exports = require('./readable').Transform
diff --git a/server/node_modules/readable-stream/writable-browser.js b/server/node_modules/readable-stream/writable-browser.js
new file mode 100644
index 0000000..ebdde6a
--- /dev/null
+++ b/server/node_modules/readable-stream/writable-browser.js
@@ -0,0 +1 @@
+module.exports = require('./lib/_stream_writable.js');
diff --git a/server/node_modules/readable-stream/writable.js b/server/node_modules/readable-stream/writable.js
new file mode 100644
index 0000000..3211a6f
--- /dev/null
+++ b/server/node_modules/readable-stream/writable.js
@@ -0,0 +1,8 @@
+var Stream = require("stream")
+var Writable = require("./lib/_stream_writable.js")
+
+if (process.env.READABLE_STREAM === 'disable') {
+  module.exports = Stream && Stream.Writable || Writable
+} else {
+  module.exports = Writable
+}
diff --git a/server/node_modules/retry/.npmignore b/server/node_modules/retry/.npmignore
new file mode 100644
index 0000000..432f285
--- /dev/null
+++ b/server/node_modules/retry/.npmignore
@@ -0,0 +1,3 @@
+/node_modules/*
+npm-debug.log
+coverage
diff --git a/server/node_modules/retry/.travis.yml b/server/node_modules/retry/.travis.yml
new file mode 100644
index 0000000..bcde212
--- /dev/null
+++ b/server/node_modules/retry/.travis.yml
@@ -0,0 +1,15 @@
+language: node_js
+node_js:
+  - "4"
+before_install:
+  - pip install --user codecov
+after_success:
+  - codecov --file coverage/lcov.info --disable search
+# travis encrypt [subdomain]:[api token]@[room id]
+# notifications:
+#   email: false
+#   campfire:
+#     rooms:
+#       secure: xyz
+#     on_failure: always
+#     on_success: always
diff --git a/server/node_modules/retry/License b/server/node_modules/retry/License
new file mode 100644
index 0000000..0b58de3
--- /dev/null
+++ b/server/node_modules/retry/License
@@ -0,0 +1,21 @@
+Copyright (c) 2011:
+Tim Koschützki (tim@debuggable.com)
+Felix Geisendörfer (felix@debuggable.com)
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ THE SOFTWARE.
diff --git a/server/node_modules/retry/Makefile b/server/node_modules/retry/Makefile
new file mode 100644
index 0000000..1968d8f
--- /dev/null
+++ b/server/node_modules/retry/Makefile
@@ -0,0 +1,18 @@
+SHELL := /bin/bash
+
+release-major: test
+	npm version major -m "Release %s"
+	git push
+	npm publish
+
+release-minor: test
+	npm version minor -m "Release %s"
+	git push
+	npm publish
+
+release-patch: test
+	npm version patch -m "Release %s"
+	git push
+	npm publish
+
+.PHONY: test release-major release-minor release-patch
diff --git a/server/node_modules/retry/README.md b/server/node_modules/retry/README.md
new file mode 100644
index 0000000..16e28ec
--- /dev/null
+++ b/server/node_modules/retry/README.md
@@ -0,0 +1,227 @@
+
+[![Build Status](https://secure.travis-ci.org/tim-kos/node-retry.png?branch=master)](http://travis-ci.org/tim-kos/node-retry "Check this project's build status on TravisCI")
+[![codecov](https://codecov.io/gh/tim-kos/node-retry/branch/master/graph/badge.svg)](https://codecov.io/gh/tim-kos/node-retry)
+
+
+# retry
+
+Abstraction for exponential and custom retry strategies for failed operations.
+
+## Installation
+
+    npm install retry
+
+## Current Status
+
+This module has been tested and is ready to be used.
+
+## Tutorial
+
+The example below will retry a potentially failing `dns.resolve` operation
+`10` times using an exponential backoff strategy. With the default settings, this
+means the last attempt is made after `17 minutes and 3 seconds`.
+
+``` javascript
+var dns = require('dns');
+var retry = require('retry');
+
+function faultTolerantResolve(address, cb) {
+  var operation = retry.operation();
+
+  operation.attempt(function(currentAttempt) {
+    dns.resolve(address, function(err, addresses) {
+      if (operation.retry(err)) {
+        return;
+      }
+
+      cb(err ? operation.mainError() : null, addresses);
+    });
+  });
+}
+
+faultTolerantResolve('nodejs.org', function(err, addresses) {
+  console.log(err, addresses);
+});
+```
+
+Of course you can also configure the factors that go into the exponential
+backoff. See the API documentation below for all available settings.
+currentAttempt is an int representing the number of attempts so far.
+
+``` javascript
+var operation = retry.operation({
+  retries: 5,
+  factor: 3,
+  minTimeout: 1 * 1000,
+  maxTimeout: 60 * 1000,
+  randomize: true,
+});
+```
+
+## API
+
+### retry.operation([options])
+
+Creates a new `RetryOperation` object. `options` is the same as `retry.timeouts()`'s `options`, with two additions:
+
+* `forever`: Whether to retry forever, defaults to `false`.
+* `unref`: Whether to [unref](https://nodejs.org/api/timers.html#timers_unref) the setTimeout's, defaults to `false`.
+* `maxRetryTime`: The maximum time (in milliseconds) that the retried operation is allowed to run. Default is `Infinity`.  
+
+### retry.timeouts([options])
+
+Returns an array of timeouts. All time `options` and return values are in
+milliseconds. If `options` is an array, a copy of that array is returned.
+
+`options` is a JS object that can contain any of the following keys:
+
+* `retries`: The maximum amount of times to retry the operation. Default is `10`. Seting this to `1` means `do it once, then retry it once`.
+* `factor`: The exponential factor to use. Default is `2`.
+* `minTimeout`: The number of milliseconds before starting the first retry. Default is `1000`.
+* `maxTimeout`: The maximum number of milliseconds between two retries. Default is `Infinity`.
+* `randomize`: Randomizes the timeouts by multiplying with a factor between `1` to `2`. Default is `false`.
+
+The formula used to calculate the individual timeouts is:
+
+```
+Math.min(random * minTimeout * Math.pow(factor, attempt), maxTimeout)
+```
+
+Have a look at [this article][article] for a better explanation of approach.
+
+If you want to tune your `factor` / `times` settings to attempt the last retry
+after a certain amount of time, you can use wolfram alpha. For example in order
+to tune for `10` attempts in `5 minutes`, you can use this equation:
+
+![screenshot](https://github.com/tim-kos/node-retry/raw/master/equation.gif)
+
+Explaining the various values from left to right:
+
+* `k = 0 ... 9`:  The `retries` value (10)
+* `1000`: The `minTimeout` value in ms (1000)
+* `x^k`: No need to change this, `x` will be your resulting factor
+* `5 * 60 * 1000`: The desired total amount of time for retrying in ms (5 minutes)
+
+To make this a little easier for you, use wolfram alpha to do the calculations:
+
+<http://www.wolframalpha.com/input/?i=Sum%5B1000*x^k%2C+{k%2C+0%2C+9}%5D+%3D+5+*+60+*+1000>
+
+[article]: http://dthain.blogspot.com/2009/02/exponential-backoff-in-distributed.html
+
+### retry.createTimeout(attempt, opts)
+
+Returns a new `timeout` (integer in milliseconds) based on the given parameters.
+
+`attempt` is an integer representing for which retry the timeout should be calculated. If your retry operation was executed 4 times you had one attempt and 3 retries. If you then want to calculate a new timeout, you should set `attempt` to 4 (attempts are zero-indexed).
+
+`opts` can include `factor`, `minTimeout`, `randomize` (boolean) and `maxTimeout`. They are documented above.
+
+`retry.createTimeout()` is used internally by `retry.timeouts()` and is public for you to be able to create your own timeouts for reinserting an item, see [issue #13](https://github.com/tim-kos/node-retry/issues/13).
+
+### retry.wrap(obj, [options], [methodNames])
+
+Wrap all functions of the `obj` with retry. Optionally you can pass operation options and
+an array of method names which need to be wrapped.
+
+```
+retry.wrap(obj)
+
+retry.wrap(obj, ['method1', 'method2'])
+
+retry.wrap(obj, {retries: 3})
+
+retry.wrap(obj, {retries: 3}, ['method1', 'method2'])
+```
+The `options` object can take any options that the usual call to `retry.operation` can take.
+
+### new RetryOperation(timeouts, [options])
+
+Creates a new `RetryOperation` where `timeouts` is an array where each value is
+a timeout given in milliseconds.
+
+Available options:
+* `forever`: Whether to retry forever, defaults to `false`.
+* `unref`: Wether to [unref](https://nodejs.org/api/timers.html#timers_unref) the setTimeout's, defaults to `false`.
+
+If `forever` is true, the following changes happen:
+* `RetryOperation.errors()` will only output an array of one item: the last error.
+* `RetryOperation` will repeatedly use the `timeouts` array. Once all of its timeouts have been used up, it restarts with the first timeout, then uses the second and so on.
+
+#### retryOperation.errors()
+
+Returns an array of all errors that have been passed to `retryOperation.retry()` so far. The
+returning array has the errors ordered chronologically based on when they were passed to
+`retryOperation.retry()`, which means the first passed error is at index zero and the last is
+at the last index.
+
+#### retryOperation.mainError()
+
+A reference to the error object that occured most frequently. Errors are
+compared using the `error.message` property.
+
+If multiple error messages occured the same amount of time, the last error
+object with that message is returned.
+
+If no errors occured so far, the value is `null`.
+
+#### retryOperation.attempt(fn, timeoutOps)
+
+Defines the function `fn` that is to be retried and executes it for the first
+time right away. The `fn` function can receive an optional `currentAttempt` callback that represents the number of attempts to execute `fn` so far.
+
+Optionally defines `timeoutOps` which is an object having a property `timeout` in miliseconds and a property `cb` callback function.
+Whenever your retry operation takes longer than `timeout` to execute, the timeout callback function `cb` is called.
+
+
+#### retryOperation.try(fn)
+
+This is an alias for `retryOperation.attempt(fn)`. This is deprecated. Please use `retryOperation.attempt(fn)` instead.
+
+#### retryOperation.start(fn)
+
+This is an alias for `retryOperation.attempt(fn)`. This is deprecated. Please use `retryOperation.attempt(fn)` instead.
+
+#### retryOperation.retry(error)
+
+Returns `false` when no `error` value is given, or the maximum amount of retries
+has been reached.
+
+Otherwise it returns `true`, and retries the operation after the timeout for
+the current attempt number.
+
+#### retryOperation.stop()
+
+Allows you to stop the operation being retried. Useful for aborting the operation on a fatal error etc.
+
+#### retryOperation.reset()
+
+Resets the internal state of the operation object, so that you can call `attempt()` again as if this was a new operation object.
+
+#### retryOperation.attempts()
+
+Returns an int representing the number of attempts it took to call `fn` before it was successful.
+
+## License
+
+retry is licensed under the MIT license.
+
+
+# Changelog
+
+0.10.0 Adding `stop` functionality, thanks to @maxnachlinger.
+
+0.9.0 Adding `unref` functionality, thanks to @satazor.
+
+0.8.0 Implementing retry.wrap.
+
+0.7.0 Some bug fixes and made retry.createTimeout() public. Fixed issues [#10](https://github.com/tim-kos/node-retry/issues/10), [#12](https://github.com/tim-kos/node-retry/issues/12), and [#13](https://github.com/tim-kos/node-retry/issues/13).
+
+0.6.0 Introduced optional timeOps parameter for the attempt() function which is an object having a property timeout in milliseconds and a property cb callback function. Whenever your retry operation takes longer than timeout to execute, the timeout callback function cb is called.
+
+0.5.0 Some minor refactoring.
+
+0.4.0 Changed retryOperation.try() to retryOperation.attempt(). Deprecated the aliases start() and try() for it.
+
+0.3.0 Added retryOperation.start() which is an alias for retryOperation.try().
+
+0.2.0 Added attempts() function and parameter to retryOperation.try() representing the number of attempts it took to call fn().
diff --git a/server/node_modules/retry/equation.gif b/server/node_modules/retry/equation.gif
new file mode 100644
index 0000000..9710723
Binary files /dev/null and b/server/node_modules/retry/equation.gif differ
diff --git a/server/node_modules/retry/example/dns.js b/server/node_modules/retry/example/dns.js
new file mode 100644
index 0000000..446729b
--- /dev/null
+++ b/server/node_modules/retry/example/dns.js
@@ -0,0 +1,31 @@
+var dns = require('dns');
+var retry = require('../lib/retry');
+
+function faultTolerantResolve(address, cb) {
+  var opts = {
+    retries: 2,
+    factor: 2,
+    minTimeout: 1 * 1000,
+    maxTimeout: 2 * 1000,
+    randomize: true
+  };
+  var operation = retry.operation(opts);
+
+  operation.attempt(function(currentAttempt) {
+    dns.resolve(address, function(err, addresses) {
+      if (operation.retry(err)) {
+        return;
+      }
+
+      cb(operation.mainError(), operation.errors(), addresses);
+    });
+  });
+}
+
+faultTolerantResolve('nodejs.org', function(err, errors, addresses) {
+  console.warn('err:');
+  console.log(err);
+
+  console.warn('addresses:');
+  console.log(addresses);
+});
\ No newline at end of file
diff --git a/server/node_modules/retry/example/stop.js b/server/node_modules/retry/example/stop.js
new file mode 100644
index 0000000..e1ceafe
--- /dev/null
+++ b/server/node_modules/retry/example/stop.js
@@ -0,0 +1,40 @@
+var retry = require('../lib/retry');
+
+function attemptAsyncOperation(someInput, cb) {
+  var opts = {
+    retries: 2,
+    factor: 2,
+    minTimeout: 1 * 1000,
+    maxTimeout: 2 * 1000,
+    randomize: true
+  };
+  var operation = retry.operation(opts);
+
+  operation.attempt(function(currentAttempt) {
+    failingAsyncOperation(someInput, function(err, result) {
+
+      if (err && err.message === 'A fatal error') {
+        operation.stop();
+        return cb(err);
+      }
+
+      if (operation.retry(err)) {
+        return;
+      }
+
+      cb(operation.mainError(), operation.errors(), result);
+    });
+  });
+}
+
+attemptAsyncOperation('test input', function(err, errors, result) {
+  console.warn('err:');
+  console.log(err);
+
+  console.warn('result:');
+  console.log(result);
+});
+
+function failingAsyncOperation(input, cb) {
+  return setImmediate(cb.bind(null, new Error('A fatal error')));
+}
diff --git a/server/node_modules/retry/index.js b/server/node_modules/retry/index.js
new file mode 100644
index 0000000..ee62f3a
--- /dev/null
+++ b/server/node_modules/retry/index.js
@@ -0,0 +1 @@
+module.exports = require('./lib/retry');
\ No newline at end of file
diff --git a/server/node_modules/retry/lib/retry.js b/server/node_modules/retry/lib/retry.js
new file mode 100644
index 0000000..dcb5768
--- /dev/null
+++ b/server/node_modules/retry/lib/retry.js
@@ -0,0 +1,100 @@
+var RetryOperation = require('./retry_operation');
+
+exports.operation = function(options) {
+  var timeouts = exports.timeouts(options);
+  return new RetryOperation(timeouts, {
+      forever: options && options.forever,
+      unref: options && options.unref,
+      maxRetryTime: options && options.maxRetryTime
+  });
+};
+
+exports.timeouts = function(options) {
+  if (options instanceof Array) {
+    return [].concat(options);
+  }
+
+  var opts = {
+    retries: 10,
+    factor: 2,
+    minTimeout: 1 * 1000,
+    maxTimeout: Infinity,
+    randomize: false
+  };
+  for (var key in options) {
+    opts[key] = options[key];
+  }
+
+  if (opts.minTimeout > opts.maxTimeout) {
+    throw new Error('minTimeout is greater than maxTimeout');
+  }
+
+  var timeouts = [];
+  for (var i = 0; i < opts.retries; i++) {
+    timeouts.push(this.createTimeout(i, opts));
+  }
+
+  if (options && options.forever && !timeouts.length) {
+    timeouts.push(this.createTimeout(i, opts));
+  }
+
+  // sort the array numerically ascending
+  timeouts.sort(function(a,b) {
+    return a - b;
+  });
+
+  return timeouts;
+};
+
+exports.createTimeout = function(attempt, opts) {
+  var random = (opts.randomize)
+    ? (Math.random() + 1)
+    : 1;
+
+  var timeout = Math.round(random * opts.minTimeout * Math.pow(opts.factor, attempt));
+  timeout = Math.min(timeout, opts.maxTimeout);
+
+  return timeout;
+};
+
+exports.wrap = function(obj, options, methods) {
+  if (options instanceof Array) {
+    methods = options;
+    options = null;
+  }
+
+  if (!methods) {
+    methods = [];
+    for (var key in obj) {
+      if (typeof obj[key] === 'function') {
+        methods.push(key);
+      }
+    }
+  }
+
+  for (var i = 0; i < methods.length; i++) {
+    var method   = methods[i];
+    var original = obj[method];
+
+    obj[method] = function retryWrapper(original) {
+      var op       = exports.operation(options);
+      var args     = Array.prototype.slice.call(arguments, 1);
+      var callback = args.pop();
+
+      args.push(function(err) {
+        if (op.retry(err)) {
+          return;
+        }
+        if (err) {
+          arguments[0] = op.mainError();
+        }
+        callback.apply(this, arguments);
+      });
+
+      op.attempt(function() {
+        original.apply(obj, args);
+      });
+    }.bind(obj, original);
+    obj[method].options = options;
+  }
+};
diff --git a/server/node_modules/retry/lib/retry_operation.js b/server/node_modules/retry/lib/retry_operation.js
new file mode 100644
index 0000000..1e56469
--- /dev/null
+++ b/server/node_modules/retry/lib/retry_operation.js
@@ -0,0 +1,158 @@
+function RetryOperation(timeouts, options) {
+  // Compatibility for the old (timeouts, retryForever) signature
+  if (typeof options === 'boolean') {
+    options = { forever: options };
+  }
+
+  this._originalTimeouts = JSON.parse(JSON.stringify(timeouts));
+  this._timeouts = timeouts;
+  this._options = options || {};
+  this._maxRetryTime = options && options.maxRetryTime || Infinity;
+  this._fn = null;
+  this._errors = [];
+  this._attempts = 1;
+  this._operationTimeout = null;
+  this._operationTimeoutCb = null;
+  this._timeout = null;
+  this._operationStart = null;
+
+  if (this._options.forever) {
+    this._cachedTimeouts = this._timeouts.slice(0);
+  }
+}
+module.exports = RetryOperation;
+
+RetryOperation.prototype.reset = function() {
+  this._attempts = 1;
+  this._timeouts = this._originalTimeouts;
+}
+
+RetryOperation.prototype.stop = function() {
+  if (this._timeout) {
+    clearTimeout(this._timeout);
+  }
+
+  this._timeouts       = [];
+  this._cachedTimeouts = null;
+};
+
+RetryOperation.prototype.retry = function(err) {
+  if (this._timeout) {
+    clearTimeout(this._timeout);
+  }
+
+  if (!err) {
+    return false;
+  }
+  var currentTime = new Date().getTime();
+  if (err && currentTime - this._operationStart >= this._maxRetryTime) {
+    this._errors.unshift(new Error('RetryOperation timeout occurred'));
+    return false;
+  }
+
+  this._errors.push(err);
+
+  var timeout = this._timeouts.shift();
+  if (timeout === undefined) {
+    if (this._cachedTimeouts) {
+      // retry forever, only keep last error
+      this._errors.splice(this._errors.length - 1, this._errors.length);
+      this._timeouts = this._cachedTimeouts.slice(0);
+      timeout = this._timeouts.shift();
+    } else {
+      return false;
+    }
+  }
+
+  var self = this;
+  var timer = setTimeout(function() {
+    self._attempts++;
+
+    if (self._operationTimeoutCb) {
+      self._timeout = setTimeout(function() {
+        self._operationTimeoutCb(self._attempts);
+      }, self._operationTimeout);
+
+      if (self._options.unref) {
+          self._timeout.unref();
+      }
+    }
+
+    self._fn(self._attempts);
+  }, timeout);
+
+  if (this._options.unref) {
+      timer.unref();
+  }
+
+  return true;
+};
+
+RetryOperation.prototype.attempt = function(fn, timeoutOps) {
+  this._fn = fn;
+
+  if (timeoutOps) {
+    if (timeoutOps.timeout) {
+      this._operationTimeout = timeoutOps.timeout;
+    }
+    if (timeoutOps.cb) {
+      this._operationTimeoutCb = timeoutOps.cb;
+    }
+  }
+
+  var self = this;
+  if (this._operationTimeoutCb) {
+    this._timeout = setTimeout(function() {
+      self._operationTimeoutCb();
+    }, self._operationTimeout);
+  }
+
+  this._operationStart = new Date().getTime();
+
+  this._fn(this._attempts);
+};
+
+RetryOperation.prototype.try = function(fn) {
+  console.log('Using RetryOperation.try() is deprecated');
+  this.attempt(fn);
+};
+
+RetryOperation.prototype.start = function(fn) {
+  console.log('Using RetryOperation.start() is deprecated');
+  this.attempt(fn);
+};
+
+RetryOperation.prototype.start = RetryOperation.prototype.try;
+
+RetryOperation.prototype.errors = function() {
+  return this._errors;
+};
+
+RetryOperation.prototype.attempts = function() {
+  return this._attempts;
+};
+
+RetryOperation.prototype.mainError = function() {
+  if (this._errors.length === 0) {
+    return null;
+  }
+
+  var counts = {};
+  var mainError = null;
+  var mainErrorCount = 0;
+
+  for (var i = 0; i < this._errors.length; i++) {
+    var error = this._errors[i];
+    var message = error.message;
+    var count = (counts[message] || 0) + 1;
+
+    counts[message] = count;
+
+    if (count >= mainErrorCount) {
+      mainError = error;
+      mainErrorCount = count;
+    }
+  }
+
+  return mainError;
+};
diff --git a/server/node_modules/retry/package.json b/server/node_modules/retry/package.json
new file mode 100644
index 0000000..73c7259
--- /dev/null
+++ b/server/node_modules/retry/package.json
@@ -0,0 +1,32 @@
+{
+  "author": "Tim Koschützki <tim@debuggable.com> (http://debuggable.com/)",
+  "name": "retry",
+  "description": "Abstraction for exponential and custom retry strategies for failed operations.",
+  "license": "MIT",
+  "version": "0.12.0",
+  "homepage": "https://github.com/tim-kos/node-retry",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/tim-kos/node-retry.git"
+  },
+  "directories": {
+    "lib": "./lib"
+  },
+  "main": "index",
+  "engines": {
+    "node": ">= 4"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "fake": "0.2.0",
+    "istanbul": "^0.4.5",
+    "tape": "^4.8.0"
+  },
+  "scripts": {
+    "test": "./node_modules/.bin/istanbul cover ./node_modules/tape/bin/tape ./test/integration/*.js",
+    "release:major": "env SEMANTIC=major npm run release",
+    "release:minor": "env SEMANTIC=minor npm run release",
+    "release:patch": "env SEMANTIC=patch npm run release",
+    "release": "npm version ${SEMANTIC:-patch} -m \"Release %s\" && git push && git push --tags && npm publish"
+  }
+}
diff --git a/server/node_modules/retry/test/common.js b/server/node_modules/retry/test/common.js
new file mode 100644
index 0000000..2247206
--- /dev/null
+++ b/server/node_modules/retry/test/common.js
@@ -0,0 +1,10 @@
+var common = module.exports;
+var path = require('path');
+
+var rootDir = path.join(__dirname, '..');
+common.dir = {
+  lib: rootDir + '/lib'
+};
+
+common.assert = require('assert');
+common.fake = require('fake');
\ No newline at end of file
diff --git a/server/node_modules/retry/test/integration/test-forever.js b/server/node_modules/retry/test/integration/test-forever.js
new file mode 100644
index 0000000..b41307c
--- /dev/null
+++ b/server/node_modules/retry/test/integration/test-forever.js
@@ -0,0 +1,24 @@
+var common = require('../common');
+var assert = common.assert;
+var retry = require(common.dir.lib + '/retry');
+
+(function testForeverUsesFirstTimeout() {
+  var operation = retry.operation({
+    retries: 0,
+    minTimeout: 100,
+    maxTimeout: 100,
+    forever: true
+  });
+
+  operation.attempt(function(numAttempt) {
+    console.log('>numAttempt', numAttempt);
+    var err = new Error("foo");
+    if (numAttempt == 10) {
+      operation.stop();
+    }
+
+    if (operation.retry(err)) {
+      return;
+    }
+  });
+})();
diff --git a/server/node_modules/retry/test/integration/test-retry-operation.js b/server/node_modules/retry/test/integration/test-retry-operation.js
new file mode 100644
index 0000000..e351bb6
--- /dev/null
+++ b/server/node_modules/retry/test/integration/test-retry-operation.js
@@ -0,0 +1,258 @@
+var common = require('../common');
+var assert = common.assert;
+var fake = common.fake.create();
+var retry = require(common.dir.lib + '/retry');
+
+(function testReset() {
+  var error = new Error('some error');
+  var operation = retry.operation([1, 2, 3]);
+  var attempts = 0;
+
+  var finalCallback = fake.callback('finalCallback');
+  fake.expectAnytime(finalCallback);
+
+  var expectedFinishes = 1;
+  var finishes         = 0;
+
+  var fn = function() {
+    operation.attempt(function(currentAttempt) {
+      attempts++;
+      assert.equal(currentAttempt, attempts);
+      if (operation.retry(error)) {
+        return;
+      }
+
+      finishes++
+      assert.equal(expectedFinishes, finishes);
+      assert.strictEqual(attempts, 4);
+      assert.strictEqual(operation.attempts(), attempts);
+      assert.strictEqual(operation.mainError(), error);
+
+      if (finishes < 2) {
+        attempts = 0;
+        expectedFinishes++;
+        operation.reset();
+        fn()
+      } else {
+        finalCallback();
+      }
+    });
+  };
+
+  fn();
+})();
+
+(function testErrors() {
+  var operation = retry.operation();
+
+  var error = new Error('some error');
+  var error2 = new Error('some other error');
+  operation._errors.push(error);
+  operation._errors.push(error2);
+
+  assert.deepEqual(operation.errors(), [error, error2]);
+})();
+
+(function testMainErrorReturnsMostFrequentError() {
+  var operation = retry.operation();
+  var error = new Error('some error');
+  var error2 = new Error('some other error');
+
+  operation._errors.push(error);
+  operation._errors.push(error2);
+  operation._errors.push(error);
+
+  assert.strictEqual(operation.mainError(), error);
+})();
+
+(function testMainErrorReturnsLastErrorOnEqualCount() {
+  var operation = retry.operation();
+  var error = new Error('some error');
+  var error2 = new Error('some other error');
+
+  operation._errors.push(error);
+  operation._errors.push(error2);
+
+  assert.strictEqual(operation.mainError(), error2);
+})();
+
+(function testAttempt() {
+  var operation = retry.operation();
+  var fn = new Function();
+
+  var timeoutOpts = {
+    timeout: 1,
+    cb: function() {}
+  };
+  operation.attempt(fn, timeoutOpts);
+
+  assert.strictEqual(fn, operation._fn);
+  assert.strictEqual(timeoutOpts.timeout, operation._operationTimeout);
+  assert.strictEqual(timeoutOpts.cb, operation._operationTimeoutCb);
+})();
+
+(function testRetry() {
+  var error = new Error('some error');
+  var operation = retry.operation([1, 2, 3]);
+  var attempts = 0;
+
+  var finalCallback = fake.callback('finalCallback');
+  fake.expectAnytime(finalCallback);
+
+  var fn = function() {
+    operation.attempt(function(currentAttempt) {
+      attempts++;
+      assert.equal(currentAttempt, attempts);
+      if (operation.retry(error)) {
+        return;
+      }
+
+      assert.strictEqual(attempts, 4);
+      assert.strictEqual(operation.attempts(), attempts);
+      assert.strictEqual(operation.mainError(), error);
+      finalCallback();
+    });
+  };
+
+  fn();
+})();
+
+(function testRetryForever() {
+  var error = new Error('some error');
+  var operation = retry.operation({ retries: 3, forever: true });
+  var attempts = 0;
+
+  var finalCallback = fake.callback('finalCallback');
+  fake.expectAnytime(finalCallback);
+
+  var fn = function() {
+    operation.attempt(function(currentAttempt) {
+      attempts++;
+      assert.equal(currentAttempt, attempts);
+      if (attempts !== 6 && operation.retry(error)) {
+        return;
+      }
+
+      assert.strictEqual(attempts, 6);
+      assert.strictEqual(operation.attempts(), attempts);
+      assert.strictEqual(operation.mainError(), error);
+      finalCallback();
+    });
+  };
+
+  fn();
+})();
+
+(function testRetryForeverNoRetries() {
+  var error = new Error('some error');
+  var delay = 50
+  var operation = retry.operation({
+    retries: null,
+    forever: true,
+    minTimeout: delay,
+    maxTimeout: delay
+  });
+
+  var attempts = 0;
+  var startTime = new Date().getTime();
+
+  var finalCallback = fake.callback('finalCallback');
+  fake.expectAnytime(finalCallback);
+
+  var fn = function() {
+    operation.attempt(function(currentAttempt) {
+      attempts++;
+      assert.equal(currentAttempt, attempts);
+      if (attempts !== 4 && operation.retry(error)) {
+        return;
+      }
+
+      var endTime = new Date().getTime();
+      var minTime = startTime + (delay * 3);
+      var maxTime = minTime + 20 // add a little headroom for code execution time
+      assert(endTime >= minTime)
+      assert(endTime < maxTime)
+      assert.strictEqual(attempts, 4);
+      assert.strictEqual(operation.attempts(), attempts);
+      assert.strictEqual(operation.mainError(), error);
+      finalCallback();
+    });
+  };
+
+  fn();
+})();
+
+(function testStop() {
+  var error = new Error('some error');
+  var operation = retry.operation([1, 2, 3]);
+  var attempts = 0;
+
+  var finalCallback = fake.callback('finalCallback');
+  fake.expectAnytime(finalCallback);
+
+  var fn = function() {
+    operation.attempt(function(currentAttempt) {
+      attempts++;
+      assert.equal(currentAttempt, attempts);
+
+      if (attempts === 2) {
+        operation.stop();
+
+        assert.strictEqual(attempts, 2);
+        assert.strictEqual(operation.attempts(), attempts);
+        assert.strictEqual(operation.mainError(), error);
+        finalCallback();
+      }
+
+      if (operation.retry(error)) {
+        return;
+      }
+    });
+  };
+
+  fn();
+})();
+
+(function testMaxRetryTime() {
+  var error = new Error('some error');
+  var maxRetryTime = 30;
+  var operation = retry.operation({
+      minTimeout: 1,
+      maxRetryTime: maxRetryTime
+  });
+  var attempts = 0;
+
+  var finalCallback = fake.callback('finalCallback');
+  fake.expectAnytime(finalCallback);
+
+  var longAsyncFunction = function (wait, callback){
+    setTimeout(callback, wait);
+  };
+
+  var fn = function() {
+    var startTime = new Date().getTime();
+    operation.attempt(function(currentAttempt) {
+      attempts++;
+      assert.equal(currentAttempt, attempts);
+
+      if (attempts !== 2) {
+        if (operation.retry(error)) {
+            return;
+        }
+      } else {
+        var curTime = new Date().getTime();
+        longAsyncFunction(maxRetryTime - (curTime - startTime - 1), function(){
+          if (operation.retry(error)) {
+            assert.fail('timeout should be occurred');
+            return;
+          }
+
+          assert.strictEqual(operation.mainError(), error);
+          finalCallback();
+        });
+      }
+    });
+  };
+
+  fn();
+})();
diff --git a/server/node_modules/retry/test/integration/test-retry-wrap.js b/server/node_modules/retry/test/integration/test-retry-wrap.js
new file mode 100644
index 0000000..3d2b6bf
--- /dev/null
+++ b/server/node_modules/retry/test/integration/test-retry-wrap.js
@@ -0,0 +1,101 @@
+var common = require('../common');
+var assert = common.assert;
+var fake = common.fake.create();
+var retry = require(common.dir.lib + '/retry');
+
+function getLib() {
+  return {
+    fn1: function() {},
+    fn2: function() {},
+    fn3: function() {}
+  };
+}
+
+(function wrapAll() {
+  var lib = getLib();
+  retry.wrap(lib);
+  assert.equal(lib.fn1.name, 'bound retryWrapper');
+  assert.equal(lib.fn2.name, 'bound retryWrapper');
+  assert.equal(lib.fn3.name, 'bound retryWrapper');
+}());
+
+(function wrapAllPassOptions() {
+  var lib = getLib();
+  retry.wrap(lib, {retries: 2});
+  assert.equal(lib.fn1.name, 'bound retryWrapper');
+  assert.equal(lib.fn2.name, 'bound retryWrapper');
+  assert.equal(lib.fn3.name, 'bound retryWrapper');
+  assert.equal(lib.fn1.options.retries, 2);
+  assert.equal(lib.fn2.options.retries, 2);
+  assert.equal(lib.fn3.options.retries, 2);
+}());
+
+(function wrapDefined() {
+  var lib = getLib();
+  retry.wrap(lib, ['fn2', 'fn3']);
+  assert.notEqual(lib.fn1.name, 'bound retryWrapper');
+  assert.equal(lib.fn2.name, 'bound retryWrapper');
+  assert.equal(lib.fn3.name, 'bound retryWrapper');
+}());
+
+(function wrapDefinedAndPassOptions() {
+  var lib = getLib();
+  retry.wrap(lib, {retries: 2}, ['fn2', 'fn3']);
+  assert.notEqual(lib.fn1.name, 'bound retryWrapper');
+  assert.equal(lib.fn2.name, 'bound retryWrapper');
+  assert.equal(lib.fn3.name, 'bound retryWrapper');
+  assert.equal(lib.fn2.options.retries, 2);
+  assert.equal(lib.fn3.options.retries, 2);
+}());
+
+(function runWrappedWithoutError() {
+  var callbackCalled;
+  var lib = {method: function(a, b, callback) {
+    assert.equal(a, 1);
+    assert.equal(b, 2);
+    assert.equal(typeof callback, 'function');
+    callback();
+  }};
+  retry.wrap(lib);
+  lib.method(1, 2, function() {
+    callbackCalled = true;
+  });
+  assert.ok(callbackCalled);
+}());
+
+(function runWrappedSeveralWithoutError() {
+  var callbacksCalled = 0;
+  var lib = {
+    fn1: function (a, callback) {
+      assert.equal(a, 1);
+      assert.equal(typeof callback, 'function');
+      callback();
+    },
+    fn2: function (a, callback) {
+      assert.equal(a, 2);
+      assert.equal(typeof callback, 'function');
+      callback();
+    }
+  };
+  retry.wrap(lib, {}, ['fn1', 'fn2']);
+  lib.fn1(1, function() {
+    callbacksCalled++;
+  });
+  lib.fn2(2, function() {
+    callbacksCalled++;
+  });
+  assert.equal(callbacksCalled, 2);
+}());
+
+(function runWrappedWithError() {
+  var callbackCalled;
+  var lib = {method: function(callback) {
+    callback(new Error('Some error'));
+  }};
+  retry.wrap(lib, {retries: 1});
+  lib.method(function(err) {
+    callbackCalled = true;
+    assert.ok(err instanceof Error);
+  });
+  assert.ok(!callbackCalled);
+}());
diff --git a/server/node_modules/retry/test/integration/test-timeouts.js b/server/node_modules/retry/test/integration/test-timeouts.js
new file mode 100644
index 0000000..7206b0f
--- /dev/null
+++ b/server/node_modules/retry/test/integration/test-timeouts.js
@@ -0,0 +1,69 @@
+var common = require('../common');
+var assert = common.assert;
+var retry = require(common.dir.lib + '/retry');
+
+(function testDefaultValues() {
+  var timeouts = retry.timeouts();
+
+  assert.equal(timeouts.length, 10);
+  assert.equal(timeouts[0], 1000);
+  assert.equal(timeouts[1], 2000);
+  assert.equal(timeouts[2], 4000);
+})();
+
+(function testDefaultValuesWithRandomize() {
+  var minTimeout = 5000;
+  var timeouts = retry.timeouts({
+    minTimeout: minTimeout,
+    randomize: true
+  });
+
+  assert.equal(timeouts.length, 10);
+  assert.ok(timeouts[0] > minTimeout);
+  assert.ok(timeouts[1] > timeouts[0]);
+  assert.ok(timeouts[2] > timeouts[1]);
+})();
+
+(function testPassedTimeoutsAreUsed() {
+  var timeoutsArray = [1000, 2000, 3000];
+  var timeouts = retry.timeouts(timeoutsArray);
+  assert.deepEqual(timeouts, timeoutsArray);
+  assert.notStrictEqual(timeouts, timeoutsArray);
+})();
+
+(function testTimeoutsAreWithinBoundaries() {
+  var minTimeout = 1000;
+  var maxTimeout = 10000;
+  var timeouts = retry.timeouts({
+    minTimeout: minTimeout,
+    maxTimeout: maxTimeout
+  });
+  for (var i = 0; i < timeouts; i++) {
+    assert.ok(timeouts[i] >= minTimeout);
+    assert.ok(timeouts[i] <= maxTimeout);
+  }
+})();
+
+(function testTimeoutsAreIncremental() {
+  var timeouts = retry.timeouts();
+  var lastTimeout = timeouts[0];
+  for (var i = 0; i < timeouts; i++) {
+    assert.ok(timeouts[i] > lastTimeout);
+    lastTimeout = timeouts[i];
+  }
+})();
+
+(function testTimeoutsAreIncrementalForFactorsLessThanOne() {
+  var timeouts = retry.timeouts({
+    retries: 3,
+    factor: 0.5
+  });
+
+  var expected = [250, 500, 1000];
+  assert.deepEqual(expected, timeouts);
+})();
+
+(function testRetries() {
+  var timeouts = retry.timeouts({retries: 2});
+  assert.strictEqual(timeouts.length, 2);
+})();
diff --git a/server/node_modules/rimraf/CHANGELOG.md b/server/node_modules/rimraf/CHANGELOG.md
new file mode 100644
index 0000000..f116f14
--- /dev/null
+++ b/server/node_modules/rimraf/CHANGELOG.md
@@ -0,0 +1,65 @@
+# v3.0
+
+- Add `--preserve-root` option to executable (default true)
+- Drop support for Node.js below version 6
+
+# v2.7
+
+- Make `glob` an optional dependency
+
+# 2.6
+
+- Retry on EBUSY on non-windows platforms as well
+- Make `rimraf.sync` 10000% more reliable on Windows
+
+# 2.5
+
+- Handle Windows EPERM when lstat-ing read-only dirs
+- Add glob option to pass options to glob
+
+# 2.4
+
+- Add EPERM to delay/retry loop
+- Add `disableGlob` option
+
+# 2.3
+
+- Make maxBusyTries and emfileWait configurable
+- Handle weird SunOS unlink-dir issue
+- Glob the CLI arg for better Windows support
+
+# 2.2
+
+- Handle ENOENT properly on Windows
+- Allow overriding fs methods
+- Treat EPERM as indicative of non-empty dir
+- Remove optional graceful-fs dep
+- Consistently return null error instead of undefined on success
+- win32: Treat ENOTEMPTY the same as EBUSY
+- Add `rimraf` binary
+
+# 2.1
+
+- Fix SunOS error code for a non-empty directory
+- Try rmdir before readdir
+- Treat EISDIR like EPERM
+- Remove chmod
+- Remove lstat polyfill, node 0.7 is not supported
+
+# 2.0
+
+- Fix myGid call to check process.getgid
+- Simplify the EBUSY backoff logic.
+- Use fs.lstat in node >= 0.7.9
+- Remove gently option
+- remove fiber implementation
+- Delete files that are marked read-only
+
+# 1.0
+
+- Allow ENOENT in sync method
+- Throw when no callback is provided
+- Make opts.gently an absolute path
+- use 'stat' if 'lstat' is not available
+- Consistent error naming, and rethrow non-ENOENT stat errors
+- add fiber implementation
diff --git a/server/node_modules/rimraf/LICENSE b/server/node_modules/rimraf/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/rimraf/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/rimraf/README.md b/server/node_modules/rimraf/README.md
new file mode 100644
index 0000000..423b8cf
--- /dev/null
+++ b/server/node_modules/rimraf/README.md
@@ -0,0 +1,101 @@
+[![Build Status](https://travis-ci.org/isaacs/rimraf.svg?branch=master)](https://travis-ci.org/isaacs/rimraf) [![Dependency Status](https://david-dm.org/isaacs/rimraf.svg)](https://david-dm.org/isaacs/rimraf) [![devDependency Status](https://david-dm.org/isaacs/rimraf/dev-status.svg)](https://david-dm.org/isaacs/rimraf#info=devDependencies)
+
+The [UNIX command](http://en.wikipedia.org/wiki/Rm_(Unix)) `rm -rf` for node.
+
+Install with `npm install rimraf`, or just drop rimraf.js somewhere.
+
+## API
+
+`rimraf(f, [opts], callback)`
+
+The first parameter will be interpreted as a globbing pattern for files. If you
+want to disable globbing you can do so with `opts.disableGlob` (defaults to
+`false`). This might be handy, for instance, if you have filenames that contain
+globbing wildcard characters.
+
+The callback will be called with an error if there is one.  Certain
+errors are handled for you:
+
+* Windows: `EBUSY` and `ENOTEMPTY` - rimraf will back off a maximum of
+  `opts.maxBusyTries` times before giving up, adding 100ms of wait
+  between each attempt.  The default `maxBusyTries` is 3.
+* `ENOENT` - If the file doesn't exist, rimraf will return
+  successfully, since your desired outcome is already the case.
+* `EMFILE` - Since `readdir` requires opening a file descriptor, it's
+  possible to hit `EMFILE` if too many file descriptors are in use.
+  In the sync case, there's nothing to be done for this.  But in the
+  async case, rimraf will gradually back off with timeouts up to
+  `opts.emfileWait` ms, which defaults to 1000.
+
+## options
+
+* unlink, chmod, stat, lstat, rmdir, readdir,
+  unlinkSync, chmodSync, statSync, lstatSync, rmdirSync, readdirSync
+
+    In order to use a custom file system library, you can override
+    specific fs functions on the options object.
+
+    If any of these functions are present on the options object, then
+    the supplied function will be used instead of the default fs
+    method.
+
+    Sync methods are only relevant for `rimraf.sync()`, of course.
+
+    For example:
+
+    ```javascript
+    var myCustomFS = require('some-custom-fs')
+
+    rimraf('some-thing', myCustomFS, callback)
+    ```
+
+* maxBusyTries
+
+    If an `EBUSY`, `ENOTEMPTY`, or `EPERM` error code is encountered
+    on Windows systems, then rimraf will retry with a linear backoff
+    wait of 100ms longer on each try.  The default maxBusyTries is 3.
+
+    Only relevant for async usage.
+
+* emfileWait
+
+    If an `EMFILE` error is encountered, then rimraf will retry
+    repeatedly with a linear backoff of 1ms longer on each try, until
+    the timeout counter hits this max.  The default limit is 1000.
+
+    If you repeatedly encounter `EMFILE` errors, then consider using
+    [graceful-fs](http://npm.im/graceful-fs) in your program.
+
+    Only relevant for async usage.
+
+* glob
+
+    Set to `false` to disable [glob](http://npm.im/glob) pattern
+    matching.
+
+    Set to an object to pass options to the glob module.  The default
+    glob options are `{ nosort: true, silent: true }`.
+
+    Glob version 6 is used in this module.
+
+    Relevant for both sync and async usage.
+
+* disableGlob
+
+    Set to any non-falsey value to disable globbing entirely.
+    (Equivalent to setting `glob: false`.)
+
+## rimraf.sync
+
+It can remove stuff synchronously, too.  But that's not so good.  Use
+the async API.  It's better.
+
+## CLI
+
+If installed with `npm install rimraf -g` it can be used as a global
+command `rimraf <path> [<path> ...]` which is useful for cross platform support.
+
+## mkdirp
+
+If you need to create a directory recursively, check out
+[mkdirp](https://github.com/substack/node-mkdirp).
diff --git a/server/node_modules/rimraf/bin.js b/server/node_modules/rimraf/bin.js
new file mode 100755
index 0000000..023814c
--- /dev/null
+++ b/server/node_modules/rimraf/bin.js
@@ -0,0 +1,68 @@
+#!/usr/bin/env node
+
+const rimraf = require('./')
+
+const path = require('path')
+
+const isRoot = arg => /^(\/|[a-zA-Z]:\\)$/.test(path.resolve(arg))
+const filterOutRoot = arg => {
+  const ok = preserveRoot === false || !isRoot(arg)
+  if (!ok) {
+    console.error(`refusing to remove ${arg}`)
+    console.error('Set --no-preserve-root to allow this')
+  }
+  return ok
+}
+
+let help = false
+let dashdash = false
+let noglob = false
+let preserveRoot = true
+const args = process.argv.slice(2).filter(arg => {
+  if (dashdash)
+    return !!arg
+  else if (arg === '--')
+    dashdash = true
+  else if (arg === '--no-glob' || arg === '-G')
+    noglob = true
+  else if (arg === '--glob' || arg === '-g')
+    noglob = false
+  else if (arg.match(/^(-+|\/)(h(elp)?|\?)$/))
+    help = true
+  else if (arg === '--preserve-root')
+    preserveRoot = true
+  else if (arg === '--no-preserve-root')
+    preserveRoot = false
+  else
+    return !!arg
+}).filter(arg => !preserveRoot || filterOutRoot(arg))
+
+const go = n => {
+  if (n >= args.length)
+    return
+  const options = noglob ? { glob: false } : {}
+  rimraf(args[n], options, er => {
+    if (er)
+      throw er
+    go(n+1)
+  })
+}
+
+if (help || args.length === 0) {
+  // If they didn't ask for help, then this is not a "success"
+  const log = help ? console.log : console.error
+  log('Usage: rimraf <path> [<path> ...]')
+  log('')
+  log('  Deletes all files and folders at "path" recursively.')
+  log('')
+  log('Options:')
+  log('')
+  log('  -h, --help          Display this usage info')
+  log('  -G, --no-glob       Do not expand glob patterns in arguments')
+  log('  -g, --glob          Expand glob patterns in arguments (default)')
+  log('  --preserve-root     Do not remove \'/\' (default)')
+  log('  --no-preserve-root  Do not treat \'/\' specially')
+  log('  --                  Stop parsing flags')
+  process.exit(help ? 0 : 1)
+} else
+  go(0)
diff --git a/server/node_modules/rimraf/package.json b/server/node_modules/rimraf/package.json
new file mode 100644
index 0000000..1bf8d5e
--- /dev/null
+++ b/server/node_modules/rimraf/package.json
@@ -0,0 +1,32 @@
+{
+  "name": "rimraf",
+  "version": "3.0.2",
+  "main": "rimraf.js",
+  "description": "A deep deletion module for node (like `rm -rf`)",
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC",
+  "repository": "git://github.com/isaacs/rimraf.git",
+  "scripts": {
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags",
+    "test": "tap test/*.js"
+  },
+  "bin": "./bin.js",
+  "dependencies": {
+    "glob": "^7.1.3"
+  },
+  "files": [
+    "LICENSE",
+    "README.md",
+    "bin.js",
+    "rimraf.js"
+  ],
+  "devDependencies": {
+    "mkdirp": "^0.5.1",
+    "tap": "^12.1.1"
+  },
+  "funding": {
+    "url": "https://github.com/sponsors/isaacs"
+  }
+}
diff --git a/server/node_modules/rimraf/rimraf.js b/server/node_modules/rimraf/rimraf.js
new file mode 100644
index 0000000..34da417
--- /dev/null
+++ b/server/node_modules/rimraf/rimraf.js
@@ -0,0 +1,360 @@
+const assert = require("assert")
+const path = require("path")
+const fs = require("fs")
+let glob = undefined
+try {
+  glob = require("glob")
+} catch (_err) {
+  // treat glob as optional.
+}
+
+const defaultGlobOpts = {
+  nosort: true,
+  silent: true
+}
+
+// for EMFILE handling
+let timeout = 0
+
+const isWindows = (process.platform === "win32")
+
+const defaults = options => {
+  const methods = [
+    'unlink',
+    'chmod',
+    'stat',
+    'lstat',
+    'rmdir',
+    'readdir'
+  ]
+  methods.forEach(m => {
+    options[m] = options[m] || fs[m]
+    m = m + 'Sync'
+    options[m] = options[m] || fs[m]
+  })
+
+  options.maxBusyTries = options.maxBusyTries || 3
+  options.emfileWait = options.emfileWait || 1000
+  if (options.glob === false) {
+    options.disableGlob = true
+  }
+  if (options.disableGlob !== true && glob === undefined) {
+    throw Error('glob dependency not found, set `options.disableGlob = true` if intentional')
+  }
+  options.disableGlob = options.disableGlob || false
+  options.glob = options.glob || defaultGlobOpts
+}
+
+const rimraf = (p, options, cb) => {
+  if (typeof options === 'function') {
+    cb = options
+    options = {}
+  }
+
+  assert(p, 'rimraf: missing path')
+  assert.equal(typeof p, 'string', 'rimraf: path should be a string')
+  assert.equal(typeof cb, 'function', 'rimraf: callback function required')
+  assert(options, 'rimraf: invalid options argument provided')
+  assert.equal(typeof options, 'object', 'rimraf: options should be object')
+
+  defaults(options)
+
+  let busyTries = 0
+  let errState = null
+  let n = 0
+
+  const next = (er) => {
+    errState = errState || er
+    if (--n === 0)
+      cb(errState)
+  }
+
+  const afterGlob = (er, results) => {
+    if (er)
+      return cb(er)
+
+    n = results.length
+    if (n === 0)
+      return cb()
+
+    results.forEach(p => {
+      const CB = (er) => {
+        if (er) {
+          if ((er.code === "EBUSY" || er.code === "ENOTEMPTY" || er.code === "EPERM") &&
+              busyTries < options.maxBusyTries) {
+            busyTries ++
+            // try again, with the same exact callback as this one.
+            return setTimeout(() => rimraf_(p, options, CB), busyTries * 100)
+          }
+
+          // this one won't happen if graceful-fs is used.
+          if (er.code === "EMFILE" && timeout < options.emfileWait) {
+            return setTimeout(() => rimraf_(p, options, CB), timeout ++)
+          }
+
+          // already gone
+          if (er.code === "ENOENT") er = null
+        }
+
+        timeout = 0
+        next(er)
+      }
+      rimraf_(p, options, CB)
+    })
+  }
+
+  if (options.disableGlob || !glob.hasMagic(p))
+    return afterGlob(null, [p])
+
+  options.lstat(p, (er, stat) => {
+    if (!er)
+      return afterGlob(null, [p])
+
+    glob(p, options.glob, afterGlob)
+  })
+
+}
+
+// Two possible strategies.
+// 1. Assume it's a file.  unlink it, then do the dir stuff on EPERM or EISDIR
+// 2. Assume it's a directory.  readdir, then do the file stuff on ENOTDIR
+//
+// Both result in an extra syscall when you guess wrong.  However, there
+// are likely far more normal files in the world than directories.  This
+// is based on the assumption that a the average number of files per
+// directory is >= 1.
+//
+// If anyone ever complains about this, then I guess the strategy could
+// be made configurable somehow.  But until then, YAGNI.
+const rimraf_ = (p, options, cb) => {
+  assert(p)
+  assert(options)
+  assert(typeof cb === 'function')
+
+  // sunos lets the root user unlink directories, which is... weird.
+  // so we have to lstat here and make sure it's not a dir.
+  options.lstat(p, (er, st) => {
+    if (er && er.code === "ENOENT")
+      return cb(null)
+
+    // Windows can EPERM on stat.  Life is suffering.
+    if (er && er.code === "EPERM" && isWindows)
+      fixWinEPERM(p, options, er, cb)
+
+    if (st && st.isDirectory())
+      return rmdir(p, options, er, cb)
+
+    options.unlink(p, er => {
+      if (er) {
+        if (er.code === "ENOENT")
+          return cb(null)
+        if (er.code === "EPERM")
+          return (isWindows)
+            ? fixWinEPERM(p, options, er, cb)
+            : rmdir(p, options, er, cb)
+        if (er.code === "EISDIR")
+          return rmdir(p, options, er, cb)
+      }
+      return cb(er)
+    })
+  })
+}
+
+const fixWinEPERM = (p, options, er, cb) => {
+  assert(p)
+  assert(options)
+  assert(typeof cb === 'function')
+
+  options.chmod(p, 0o666, er2 => {
+    if (er2)
+      cb(er2.code === "ENOENT" ? null : er)
+    else
+      options.stat(p, (er3, stats) => {
+        if (er3)
+          cb(er3.code === "ENOENT" ? null : er)
+        else if (stats.isDirectory())
+          rmdir(p, options, er, cb)
+        else
+          options.unlink(p, cb)
+      })
+  })
+}
+
+const fixWinEPERMSync = (p, options, er) => {
+  assert(p)
+  assert(options)
+
+  try {
+    options.chmodSync(p, 0o666)
+  } catch (er2) {
+    if (er2.code === "ENOENT")
+      return
+    else
+      throw er
+  }
+
+  let stats
+  try {
+    stats = options.statSync(p)
+  } catch (er3) {
+    if (er3.code === "ENOENT")
+      return
+    else
+      throw er
+  }
+
+  if (stats.isDirectory())
+    rmdirSync(p, options, er)
+  else
+    options.unlinkSync(p)
+}
+
+const rmdir = (p, options, originalEr, cb) => {
+  assert(p)
+  assert(options)
+  assert(typeof cb === 'function')
+
+  // try to rmdir first, and only readdir on ENOTEMPTY or EEXIST (SunOS)
+  // if we guessed wrong, and it's not a directory, then
+  // raise the original error.
+  options.rmdir(p, er => {
+    if (er && (er.code === "ENOTEMPTY" || er.code === "EEXIST" || er.code === "EPERM"))
+      rmkids(p, options, cb)
+    else if (er && er.code === "ENOTDIR")
+      cb(originalEr)
+    else
+      cb(er)
+  })
+}
+
+const rmkids = (p, options, cb) => {
+  assert(p)
+  assert(options)
+  assert(typeof cb === 'function')
+
+  options.readdir(p, (er, files) => {
+    if (er)
+      return cb(er)
+    let n = files.length
+    if (n === 0)
+      return options.rmdir(p, cb)
+    let errState
+    files.forEach(f => {
+      rimraf(path.join(p, f), options, er => {
+        if (errState)
+          return
+        if (er)
+          return cb(errState = er)
+        if (--n === 0)
+          options.rmdir(p, cb)
+      })
+    })
+  })
+}
+
+// this looks simpler, and is strictly *faster*, but will
+// tie up the JavaScript thread and fail on excessively
+// deep directory trees.
+const rimrafSync = (p, options) => {
+  options = options || {}
+  defaults(options)
+
+  assert(p, 'rimraf: missing path')
+  assert.equal(typeof p, 'string', 'rimraf: path should be a string')
+  assert(options, 'rimraf: missing options')
+  assert.equal(typeof options, 'object', 'rimraf: options should be object')
+
+  let results
+
+  if (options.disableGlob || !glob.hasMagic(p)) {
+    results = [p]
+  } else {
+    try {
+      options.lstatSync(p)
+      results = [p]
+    } catch (er) {
+      results = glob.sync(p, options.glob)
+    }
+  }
+
+  if (!results.length)
+    return
+
+  for (let i = 0; i < results.length; i++) {
+    const p = results[i]
+
+    let st
+    try {
+      st = options.lstatSync(p)
+    } catch (er) {
+      if (er.code === "ENOENT")
+        return
+
+      // Windows can EPERM on stat.  Life is suffering.
+      if (er.code === "EPERM" && isWindows)
+        fixWinEPERMSync(p, options, er)
+    }
+
+    try {
+      // sunos lets the root user unlink directories, which is... weird.
+      if (st && st.isDirectory())
+        rmdirSync(p, options, null)
+      else
+        options.unlinkSync(p)
+    } catch (er) {
+      if (er.code === "ENOENT")
+        return
+      if (er.code === "EPERM")
+        return isWindows ? fixWinEPERMSync(p, options, er) : rmdirSync(p, options, er)
+      if (er.code !== "EISDIR")
+        throw er
+
+      rmdirSync(p, options, er)
+    }
+  }
+}
+
+const rmdirSync = (p, options, originalEr) => {
+  assert(p)
+  assert(options)
+
+  try {
+    options.rmdirSync(p)
+  } catch (er) {
+    if (er.code === "ENOENT")
+      return
+    if (er.code === "ENOTDIR")
+      throw originalEr
+    if (er.code === "ENOTEMPTY" || er.code === "EEXIST" || er.code === "EPERM")
+      rmkidsSync(p, options)
+  }
+}
+
+const rmkidsSync = (p, options) => {
+  assert(p)
+  assert(options)
+  options.readdirSync(p).forEach(f => rimrafSync(path.join(p, f), options))
+
+  // We only end up here once we got ENOTEMPTY at least once, and
+  // at this point, we are guaranteed to have removed all the kids.
+  // So, we know that it won't be ENOENT or ENOTDIR or anything else.
+  // try really hard to delete stuff on windows, because it has a
+  // PROFOUNDLY annoying habit of not closing handles promptly when
+  // files are deleted, resulting in spurious ENOTEMPTY errors.
+  const retries = isWindows ? 100 : 1
+  let i = 0
+  do {
+    let threw = true
+    try {
+      const ret = options.rmdirSync(p, options)
+      threw = false
+      return ret
+    } finally {
+      if (++i < retries && threw)
+        continue
+    }
+  } while (true)
+}
+
+module.exports = rimraf
+rimraf.sync = rimrafSync
diff --git a/server/node_modules/safe-buffer/LICENSE b/server/node_modules/safe-buffer/LICENSE
new file mode 100644
index 0000000..0c068ce
--- /dev/null
+++ b/server/node_modules/safe-buffer/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Feross Aboukhadijeh
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/safe-buffer/README.md b/server/node_modules/safe-buffer/README.md
new file mode 100644
index 0000000..e9a81af
--- /dev/null
+++ b/server/node_modules/safe-buffer/README.md
@@ -0,0 +1,584 @@
+# safe-buffer [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![downloads][downloads-image]][downloads-url] [![javascript style guide][standard-image]][standard-url]
+
+[travis-image]: https://img.shields.io/travis/feross/safe-buffer/master.svg
+[travis-url]: https://travis-ci.org/feross/safe-buffer
+[npm-image]: https://img.shields.io/npm/v/safe-buffer.svg
+[npm-url]: https://npmjs.org/package/safe-buffer
+[downloads-image]: https://img.shields.io/npm/dm/safe-buffer.svg
+[downloads-url]: https://npmjs.org/package/safe-buffer
+[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
+[standard-url]: https://standardjs.com
+
+#### Safer Node.js Buffer API
+
+**Use the new Node.js Buffer APIs (`Buffer.from`, `Buffer.alloc`,
+`Buffer.allocUnsafe`, `Buffer.allocUnsafeSlow`) in all versions of Node.js.**
+
+**Uses the built-in implementation when available.**
+
+## install
+
+```
+npm install safe-buffer
+```
+
+## usage
+
+The goal of this package is to provide a safe replacement for the node.js `Buffer`.
+
+It's a drop-in replacement for `Buffer`. You can use it by adding one `require` line to
+the top of your node.js modules:
+
+```js
+var Buffer = require('safe-buffer').Buffer
+
+// Existing buffer code will continue to work without issues:
+
+new Buffer('hey', 'utf8')
+new Buffer([1, 2, 3], 'utf8')
+new Buffer(obj)
+new Buffer(16) // create an uninitialized buffer (potentially unsafe)
+
+// But you can use these new explicit APIs to make clear what you want:
+
+Buffer.from('hey', 'utf8') // convert from many types to a Buffer
+Buffer.alloc(16) // create a zero-filled buffer (safe)
+Buffer.allocUnsafe(16) // create an uninitialized buffer (potentially unsafe)
+```
+
+## api
+
+### Class Method: Buffer.from(array)
+
+
+* `array` {Array}
+
+Allocates a new `Buffer` using an `array` of octets.
+
+```js
+const buf = Buffer.from([0x62,0x75,0x66,0x66,0x65,0x72]);
+  // creates a new Buffer containing ASCII bytes
+  // ['b','u','f','f','e','r']
+```
+
+A `TypeError` will be thrown if `array` is not an `Array`.
+
+### Class Method: Buffer.from(arrayBuffer[, byteOffset[, length]])
+
+
+* `arrayBuffer` {ArrayBuffer} The `.buffer` property of a `TypedArray` or
+  a `new ArrayBuffer()`
+* `byteOffset` {Number} Default: `0`
+* `length` {Number} Default: `arrayBuffer.length - byteOffset`
+
+When passed a reference to the `.buffer` property of a `TypedArray` instance,
+the newly created `Buffer` will share the same allocated memory as the
+TypedArray.
+
+```js
+const arr = new Uint16Array(2);
+arr[0] = 5000;
+arr[1] = 4000;
+
+const buf = Buffer.from(arr.buffer); // shares the memory with arr;
+
+console.log(buf);
+  // Prints: <Buffer 88 13 a0 0f>
+
+// changing the TypedArray changes the Buffer also
+arr[1] = 6000;
+
+console.log(buf);
+  // Prints: <Buffer 88 13 70 17>
+```
+
+The optional `byteOffset` and `length` arguments specify a memory range within
+the `arrayBuffer` that will be shared by the `Buffer`.
+
+```js
+const ab = new ArrayBuffer(10);
+const buf = Buffer.from(ab, 0, 2);
+console.log(buf.length);
+  // Prints: 2
+```
+
+A `TypeError` will be thrown if `arrayBuffer` is not an `ArrayBuffer`.
+
+### Class Method: Buffer.from(buffer)
+
+
+* `buffer` {Buffer}
+
+Copies the passed `buffer` data onto a new `Buffer` instance.
+
+```js
+const buf1 = Buffer.from('buffer');
+const buf2 = Buffer.from(buf1);
+
+buf1[0] = 0x61;
+console.log(buf1.toString());
+  // 'auffer'
+console.log(buf2.toString());
+  // 'buffer' (copy is not changed)
+```
+
+A `TypeError` will be thrown if `buffer` is not a `Buffer`.
+
+### Class Method: Buffer.from(str[, encoding])
+
+
+* `str` {String} String to encode.
+* `encoding` {String} Encoding to use, Default: `'utf8'`
+
+Creates a new `Buffer` containing the given JavaScript string `str`. If
+provided, the `encoding` parameter identifies the character encoding.
+If not provided, `encoding` defaults to `'utf8'`.
+
+```js
+const buf1 = Buffer.from('this is a tést');
+console.log(buf1.toString());
+  // prints: this is a tést
+console.log(buf1.toString('ascii'));
+  // prints: this is a tC)st
+
+const buf2 = Buffer.from('7468697320697320612074c3a97374', 'hex');
+console.log(buf2.toString());
+  // prints: this is a tést
+```
+
+A `TypeError` will be thrown if `str` is not a string.
+
+### Class Method: Buffer.alloc(size[, fill[, encoding]])
+
+
+* `size` {Number}
+* `fill` {Value} Default: `undefined`
+* `encoding` {String} Default: `utf8`
+
+Allocates a new `Buffer` of `size` bytes. If `fill` is `undefined`, the
+`Buffer` will be *zero-filled*.
+
+```js
+const buf = Buffer.alloc(5);
+console.log(buf);
+  // <Buffer 00 00 00 00 00>
+```
+
+The `size` must be less than or equal to the value of
+`require('buffer').kMaxLength` (on 64-bit architectures, `kMaxLength` is
+`(2^31)-1`). Otherwise, a [`RangeError`][] is thrown. A zero-length Buffer will
+be created if a `size` less than or equal to 0 is specified.
+
+If `fill` is specified, the allocated `Buffer` will be initialized by calling
+`buf.fill(fill)`. See [`buf.fill()`][] for more information.
+
+```js
+const buf = Buffer.alloc(5, 'a');
+console.log(buf);
+  // <Buffer 61 61 61 61 61>
+```
+
+If both `fill` and `encoding` are specified, the allocated `Buffer` will be
+initialized by calling `buf.fill(fill, encoding)`. For example:
+
+```js
+const buf = Buffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');
+console.log(buf);
+  // <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64>
+```
+
+Calling `Buffer.alloc(size)` can be significantly slower than the alternative
+`Buffer.allocUnsafe(size)` but ensures that the newly created `Buffer` instance
+contents will *never contain sensitive data*.
+
+A `TypeError` will be thrown if `size` is not a number.
+
+### Class Method: Buffer.allocUnsafe(size)
+
+
+* `size` {Number}
+
+Allocates a new *non-zero-filled* `Buffer` of `size` bytes.  The `size` must
+be less than or equal to the value of `require('buffer').kMaxLength` (on 64-bit
+architectures, `kMaxLength` is `(2^31)-1`). Otherwise, a [`RangeError`][] is
+thrown. A zero-length Buffer will be created if a `size` less than or equal to
+0 is specified.
+
+The underlying memory for `Buffer` instances created in this way is *not
+initialized*. The contents of the newly created `Buffer` are unknown and
+*may contain sensitive data*. Use [`buf.fill(0)`][] to initialize such
+`Buffer` instances to zeroes.
+
+```js
+const buf = Buffer.allocUnsafe(5);
+console.log(buf);
+  // <Buffer 78 e0 82 02 01>
+  // (octets will be different, every time)
+buf.fill(0);
+console.log(buf);
+  // <Buffer 00 00 00 00 00>
+```
+
+A `TypeError` will be thrown if `size` is not a number.
+
+Note that the `Buffer` module pre-allocates an internal `Buffer` instance of
+size `Buffer.poolSize` that is used as a pool for the fast allocation of new
+`Buffer` instances created using `Buffer.allocUnsafe(size)` (and the deprecated
+`new Buffer(size)` constructor) only when `size` is less than or equal to
+`Buffer.poolSize >> 1` (floor of `Buffer.poolSize` divided by two). The default
+value of `Buffer.poolSize` is `8192` but can be modified.
+
+Use of this pre-allocated internal memory pool is a key difference between
+calling `Buffer.alloc(size, fill)` vs. `Buffer.allocUnsafe(size).fill(fill)`.
+Specifically, `Buffer.alloc(size, fill)` will *never* use the internal Buffer
+pool, while `Buffer.allocUnsafe(size).fill(fill)` *will* use the internal
+Buffer pool if `size` is less than or equal to half `Buffer.poolSize`. The
+difference is subtle but can be important when an application requires the
+additional performance that `Buffer.allocUnsafe(size)` provides.
+
+### Class Method: Buffer.allocUnsafeSlow(size)
+
+
+* `size` {Number}
+
+Allocates a new *non-zero-filled* and non-pooled `Buffer` of `size` bytes.  The
+`size` must be less than or equal to the value of
+`require('buffer').kMaxLength` (on 64-bit architectures, `kMaxLength` is
+`(2^31)-1`). Otherwise, a [`RangeError`][] is thrown. A zero-length Buffer will
+be created if a `size` less than or equal to 0 is specified.
+
+The underlying memory for `Buffer` instances created in this way is *not
+initialized*. The contents of the newly created `Buffer` are unknown and
+*may contain sensitive data*. Use [`buf.fill(0)`][] to initialize such
+`Buffer` instances to zeroes.
+
+When using `Buffer.allocUnsafe()` to allocate new `Buffer` instances,
+allocations under 4KB are, by default, sliced from a single pre-allocated
+`Buffer`. This allows applications to avoid the garbage collection overhead of
+creating many individually allocated Buffers. This approach improves both
+performance and memory usage by eliminating the need to track and cleanup as
+many `Persistent` objects.
+
+However, in the case where a developer may need to retain a small chunk of
+memory from a pool for an indeterminate amount of time, it may be appropriate
+to create an un-pooled Buffer instance using `Buffer.allocUnsafeSlow()` then
+copy out the relevant bits.
+
+```js
+// need to keep around a few small chunks of memory
+const store = [];
+
+socket.on('readable', () => {
+  const data = socket.read();
+  // allocate for retained data
+  const sb = Buffer.allocUnsafeSlow(10);
+  // copy the data into the new allocation
+  data.copy(sb, 0, 0, 10);
+  store.push(sb);
+});
+```
+
+Use of `Buffer.allocUnsafeSlow()` should be used only as a last resort *after*
+a developer has observed undue memory retention in their applications.
+
+A `TypeError` will be thrown if `size` is not a number.
+
+### All the Rest
+
+The rest of the `Buffer` API is exactly the same as in node.js.
+[See the docs](https://nodejs.org/api/buffer.html).
+
+
+## Related links
+
+- [Node.js issue: Buffer(number) is unsafe](https://github.com/nodejs/node/issues/4660)
+- [Node.js Enhancement Proposal: Buffer.from/Buffer.alloc/Buffer.zalloc/Buffer() soft-deprecate](https://github.com/nodejs/node-eps/pull/4)
+
+## Why is `Buffer` unsafe?
+
+Today, the node.js `Buffer` constructor is overloaded to handle many different argument
+types like `String`, `Array`, `Object`, `TypedArrayView` (`Uint8Array`, etc.),
+`ArrayBuffer`, and also `Number`.
+
+The API is optimized for convenience: you can throw any type at it, and it will try to do
+what you want.
+
+Because the Buffer constructor is so powerful, you often see code like this:
+
+```js
+// Convert UTF-8 strings to hex
+function toHex (str) {
+  return new Buffer(str).toString('hex')
+}
+```
+
+***But what happens if `toHex` is called with a `Number` argument?***
+
+### Remote Memory Disclosure
+
+If an attacker can make your program call the `Buffer` constructor with a `Number`
+argument, then they can make it allocate uninitialized memory from the node.js process.
+This could potentially disclose TLS private keys, user data, or database passwords.
+
+When the `Buffer` constructor is passed a `Number` argument, it returns an
+**UNINITIALIZED** block of memory of the specified `size`. When you create a `Buffer` like
+this, you **MUST** overwrite the contents before returning it to the user.
+
+From the [node.js docs](https://nodejs.org/api/buffer.html#buffer_new_buffer_size):
+
+> `new Buffer(size)`
+>
+> - `size` Number
+>
+> The underlying memory for `Buffer` instances created in this way is not initialized.
+> **The contents of a newly created `Buffer` are unknown and could contain sensitive
+> data.** Use `buf.fill(0)` to initialize a Buffer to zeroes.
+
+(Emphasis our own.)
+
+Whenever the programmer intended to create an uninitialized `Buffer` you often see code
+like this:
+
+```js
+var buf = new Buffer(16)
+
+// Immediately overwrite the uninitialized buffer with data from another buffer
+for (var i = 0; i < buf.length; i++) {
+  buf[i] = otherBuf[i]
+}
+```
+
+
+### Would this ever be a problem in real code?
+
+Yes. It's surprisingly common to forget to check the type of your variables in a
+dynamically-typed language like JavaScript.
+
+Usually the consequences of assuming the wrong type is that your program crashes with an
+uncaught exception. But the failure mode for forgetting to check the type of arguments to
+the `Buffer` constructor is more catastrophic.
+
+Here's an example of a vulnerable service that takes a JSON payload and converts it to
+hex:
+
+```js
+// Take a JSON payload {str: "some string"} and convert it to hex
+var server = http.createServer(function (req, res) {
+  var data = ''
+  req.setEncoding('utf8')
+  req.on('data', function (chunk) {
+    data += chunk
+  })
+  req.on('end', function () {
+    var body = JSON.parse(data)
+    res.end(new Buffer(body.str).toString('hex'))
+  })
+})
+
+server.listen(8080)
+```
+
+In this example, an http client just has to send:
+
+```json
+{
+  "str": 1000
+}
+```
+
+and it will get back 1,000 bytes of uninitialized memory from the server.
+
+This is a very serious bug. It's similar in severity to the
+[the Heartbleed bug](http://heartbleed.com/) that allowed disclosure of OpenSSL process
+memory by remote attackers.
+
+
+### Which real-world packages were vulnerable?
+
+#### [`bittorrent-dht`](https://www.npmjs.com/package/bittorrent-dht)
+
+[Mathias Buus](https://github.com/mafintosh) and I
+([Feross Aboukhadijeh](http://feross.org/)) found this issue in one of our own packages,
+[`bittorrent-dht`](https://www.npmjs.com/package/bittorrent-dht). The bug would allow
+anyone on the internet to send a series of messages to a user of `bittorrent-dht` and get
+them to reveal 20 bytes at a time of uninitialized memory from the node.js process.
+
+Here's
+[the commit](https://github.com/feross/bittorrent-dht/commit/6c7da04025d5633699800a99ec3fbadf70ad35b8)
+that fixed it. We released a new fixed version, created a
+[Node Security Project disclosure](https://nodesecurity.io/advisories/68), and deprecated all
+vulnerable versions on npm so users will get a warning to upgrade to a newer version.
+
+#### [`ws`](https://www.npmjs.com/package/ws)
+
+That got us wondering if there were other vulnerable packages. Sure enough, within a short
+period of time, we found the same issue in [`ws`](https://www.npmjs.com/package/ws), the
+most popular WebSocket implementation in node.js.
+
+If certain APIs were called with `Number` parameters instead of `String` or `Buffer` as
+expected, then uninitialized server memory would be disclosed to the remote peer.
+
+These were the vulnerable methods:
+
+```js
+socket.send(number)
+socket.ping(number)
+socket.pong(number)
+```
+
+Here's a vulnerable socket server with some echo functionality:
+
+```js
+server.on('connection', function (socket) {
+  socket.on('message', function (message) {
+    message = JSON.parse(message)
+    if (message.type === 'echo') {
+      socket.send(message.data) // send back the user's message
+    }
+  })
+})
+```
+
+`socket.send(number)` called on the server, will disclose server memory.
+
+Here's [the release](https://github.com/websockets/ws/releases/tag/1.0.1) where the issue
+was fixed, with a more detailed explanation. Props to
+[Arnout Kazemier](https://github.com/3rd-Eden) for the quick fix. Here's the
+[Node Security Project disclosure](https://nodesecurity.io/advisories/67).
+
+
+### What's the solution?
+
+It's important that node.js offers a fast way to get memory otherwise performance-critical
+applications would needlessly get a lot slower.
+
+But we need a better way to *signal our intent* as programmers. **When we want
+uninitialized memory, we should request it explicitly.**
+
+Sensitive functionality should not be packed into a developer-friendly API that loosely
+accepts many different types. This type of API encourages the lazy practice of passing
+variables in without checking the type very carefully.
+
+#### A new API: `Buffer.allocUnsafe(number)`
+
+The functionality of creating buffers with uninitialized memory should be part of another
+API. We propose `Buffer.allocUnsafe(number)`. This way, it's not part of an API that
+frequently gets user input of all sorts of different types passed into it.
+
+```js
+var buf = Buffer.allocUnsafe(16) // careful, uninitialized memory!
+
+// Immediately overwrite the uninitialized buffer with data from another buffer
+for (var i = 0; i < buf.length; i++) {
+  buf[i] = otherBuf[i]
+}
+```
+
+
+### How do we fix node.js core?
+
+We sent [a PR to node.js core](https://github.com/nodejs/node/pull/4514) (merged as
+`semver-major`) which defends against one case:
+
+```js
+var str = 16
+new Buffer(str, 'utf8')
+```
+
+In this situation, it's implied that the programmer intended the first argument to be a
+string, since they passed an encoding as a second argument. Today, node.js will allocate
+uninitialized memory in the case of `new Buffer(number, encoding)`, which is probably not
+what the programmer intended.
+
+But this is only a partial solution, since if the programmer does `new Buffer(variable)`
+(without an `encoding` parameter) there's no way to know what they intended. If `variable`
+is sometimes a number, then uninitialized memory will sometimes be returned.
+
+### What's the real long-term fix?
+
+We could deprecate and remove `new Buffer(number)` and use `Buffer.allocUnsafe(number)` when
+we need uninitialized memory. But that would break 1000s of packages.
+
+~~We believe the best solution is to:~~
+
+~~1. Change `new Buffer(number)` to return safe, zeroed-out memory~~
+
+~~2. Create a new API for creating uninitialized Buffers. We propose: `Buffer.allocUnsafe(number)`~~
+
+#### Update
+
+We now support adding three new APIs:
+
+- `Buffer.from(value)` - convert from any type to a buffer
+- `Buffer.alloc(size)` - create a zero-filled buffer
+- `Buffer.allocUnsafe(size)` - create an uninitialized buffer with given size
+
+This solves the core problem that affected `ws` and `bittorrent-dht` which is
+`Buffer(variable)` getting tricked into taking a number argument.
+
+This way, existing code continues working and the impact on the npm ecosystem will be
+minimal. Over time, npm maintainers can migrate performance-critical code to use
+`Buffer.allocUnsafe(number)` instead of `new Buffer(number)`.
+
+
+### Conclusion
+
+We think there's a serious design issue with the `Buffer` API as it exists today. It
+promotes insecure software by putting high-risk functionality into a convenient API
+with friendly "developer ergonomics".
+
+This wasn't merely a theoretical exercise because we found the issue in some of the
+most popular npm packages.
+
+Fortunately, there's an easy fix that can be applied today. Use `safe-buffer` in place of
+`buffer`.
+
+```js
+var Buffer = require('safe-buffer').Buffer
+```
+
+Eventually, we hope that node.js core can switch to this new, safer behavior. We believe
+the impact on the ecosystem would be minimal since it's not a breaking change.
+Well-maintained, popular packages would be updated to use `Buffer.alloc` quickly, while
+older, insecure packages would magically become safe from this attack vector.
+
+
+## links
+
+- [Node.js PR: buffer: throw if both length and enc are passed](https://github.com/nodejs/node/pull/4514)
+- [Node Security Project disclosure for `ws`](https://nodesecurity.io/advisories/67)
+- [Node Security Project disclosure for`bittorrent-dht`](https://nodesecurity.io/advisories/68)
+
+
+## credit
+
+The original issues in `bittorrent-dht`
+([disclosure](https://nodesecurity.io/advisories/68)) and
+`ws` ([disclosure](https://nodesecurity.io/advisories/67)) were discovered by
+[Mathias Buus](https://github.com/mafintosh) and
+[Feross Aboukhadijeh](http://feross.org/).
+
+Thanks to [Adam Baldwin](https://github.com/evilpacket) for helping disclose these issues
+and for his work running the [Node Security Project](https://nodesecurity.io/).
+
+Thanks to [John Hiesey](https://github.com/jhiesey) for proofreading this README and
+auditing the code.
+
+
+## license
+
+MIT. Copyright (C) [Feross Aboukhadijeh](http://feross.org)
diff --git a/server/node_modules/safe-buffer/index.d.ts b/server/node_modules/safe-buffer/index.d.ts
new file mode 100644
index 0000000..e9fed80
--- /dev/null
+++ b/server/node_modules/safe-buffer/index.d.ts
@@ -0,0 +1,187 @@
+declare module "safe-buffer" {
+  export class Buffer {
+    length: number
+    write(string: string, offset?: number, length?: number, encoding?: string): number;
+    toString(encoding?: string, start?: number, end?: number): string;
+    toJSON(): { type: 'Buffer', data: any[] };
+    equals(otherBuffer: Buffer): boolean;
+    compare(otherBuffer: Buffer, targetStart?: number, targetEnd?: number, sourceStart?: number, sourceEnd?: number): number;
+    copy(targetBuffer: Buffer, targetStart?: number, sourceStart?: number, sourceEnd?: number): number;
+    slice(start?: number, end?: number): Buffer;
+    writeUIntLE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeUIntBE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeIntLE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeIntBE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    readUIntLE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readUIntBE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readIntLE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readIntBE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readUInt8(offset: number, noAssert?: boolean): number;
+    readUInt16LE(offset: number, noAssert?: boolean): number;
+    readUInt16BE(offset: number, noAssert?: boolean): number;
+    readUInt32LE(offset: number, noAssert?: boolean): number;
+    readUInt32BE(offset: number, noAssert?: boolean): number;
+    readInt8(offset: number, noAssert?: boolean): number;
+    readInt16LE(offset: number, noAssert?: boolean): number;
+    readInt16BE(offset: number, noAssert?: boolean): number;
+    readInt32LE(offset: number, noAssert?: boolean): number;
+    readInt32BE(offset: number, noAssert?: boolean): number;
+    readFloatLE(offset: number, noAssert?: boolean): number;
+    readFloatBE(offset: number, noAssert?: boolean): number;
+    readDoubleLE(offset: number, noAssert?: boolean): number;
+    readDoubleBE(offset: number, noAssert?: boolean): number;
+    swap16(): Buffer;
+    swap32(): Buffer;
+    swap64(): Buffer;
+    writeUInt8(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt16LE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt16BE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt32LE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt32BE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt8(value: number, offset: number, noAssert?: boolean): number;
+    writeInt16LE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt16BE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt32LE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt32BE(value: number, offset: number, noAssert?: boolean): number;
+    writeFloatLE(value: number, offset: number, noAssert?: boolean): number;
+    writeFloatBE(value: number, offset: number, noAssert?: boolean): number;
+    writeDoubleLE(value: number, offset: number, noAssert?: boolean): number;
+    writeDoubleBE(value: number, offset: number, noAssert?: boolean): number;
+    fill(value: any, offset?: number, end?: number): this;
+    indexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
+    lastIndexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
+    includes(value: string | number | Buffer, byteOffset?: number, encoding?: string): boolean;
+
+    /**
+     * Allocates a new buffer containing the given {str}.
+     *
+     * @param str String to store in buffer.
+     * @param encoding encoding to use, optional.  Default is 'utf8'
+     */
+     constructor (str: string, encoding?: string);
+    /**
+     * Allocates a new buffer of {size} octets.
+     *
+     * @param size count of octets to allocate.
+     */
+    constructor (size: number);
+    /**
+     * Allocates a new buffer containing the given {array} of octets.
+     *
+     * @param array The octets to store.
+     */
+    constructor (array: Uint8Array);
+    /**
+     * Produces a Buffer backed by the same allocated memory as
+     * the given {ArrayBuffer}.
+     *
+     *
+     * @param arrayBuffer The ArrayBuffer with which to share memory.
+     */
+    constructor (arrayBuffer: ArrayBuffer);
+    /**
+     * Allocates a new buffer containing the given {array} of octets.
+     *
+     * @param array The octets to store.
+     */
+    constructor (array: any[]);
+    /**
+     * Copies the passed {buffer} data onto a new {Buffer} instance.
+     *
+     * @param buffer The buffer to copy.
+     */
+    constructor (buffer: Buffer);
+    prototype: Buffer;
+    /**
+     * Allocates a new Buffer using an {array} of octets.
+     *
+     * @param array
+     */
+    static from(array: any[]): Buffer;
+    /**
+     * When passed a reference to the .buffer property of a TypedArray instance,
+     * the newly created Buffer will share the same allocated memory as the TypedArray.
+     * The optional {byteOffset} and {length} arguments specify a memory range
+     * within the {arrayBuffer} that will be shared by the Buffer.
+     *
+     * @param arrayBuffer The .buffer property of a TypedArray or a new ArrayBuffer()
+     * @param byteOffset
+     * @param length
+     */
+    static from(arrayBuffer: ArrayBuffer, byteOffset?: number, length?: number): Buffer;
+    /**
+     * Copies the passed {buffer} data onto a new Buffer instance.
+     *
+     * @param buffer
+     */
+    static from(buffer: Buffer): Buffer;
+    /**
+     * Creates a new Buffer containing the given JavaScript string {str}.
+     * If provided, the {encoding} parameter identifies the character encoding.
+     * If not provided, {encoding} defaults to 'utf8'.
+     *
+     * @param str
+     */
+    static from(str: string, encoding?: string): Buffer;
+    /**
+     * Returns true if {obj} is a Buffer
+     *
+     * @param obj object to test.
+     */
+    static isBuffer(obj: any): obj is Buffer;
+    /**
+     * Returns true if {encoding} is a valid encoding argument.
+     * Valid string encodings in Node 0.12: 'ascii'|'utf8'|'utf16le'|'ucs2'(alias of 'utf16le')|'base64'|'binary'(deprecated)|'hex'
+     *
+     * @param encoding string to test.
+     */
+    static isEncoding(encoding: string): boolean;
+    /**
+     * Gives the actual byte length of a string. encoding defaults to 'utf8'.
+     * This is not the same as String.prototype.length since that returns the number of characters in a string.
+     *
+     * @param string string to test.
+     * @param encoding encoding used to evaluate (defaults to 'utf8')
+     */
+    static byteLength(string: string, encoding?: string): number;
+    /**
+     * Returns a buffer which is the result of concatenating all the buffers in the list together.
+     *
+     * If the list has no items, or if the totalLength is 0, then it returns a zero-length buffer.
+     * If the list has exactly one item, then the first item of the list is returned.
+     * If the list has more than one item, then a new Buffer is created.
+     *
+     * @param list An array of Buffer objects to concatenate
+     * @param totalLength Total length of the buffers when concatenated.
+     *   If totalLength is not provided, it is read from the buffers in the list. However, this adds an additional loop to the function, so it is faster to provide the length explicitly.
+     */
+    static concat(list: Buffer[], totalLength?: number): Buffer;
+    /**
+     * The same as buf1.compare(buf2).
+     */
+    static compare(buf1: Buffer, buf2: Buffer): number;
+    /**
+     * Allocates a new buffer of {size} octets.
+     *
+     * @param size count of octets to allocate.
+     * @param fill if specified, buffer will be initialized by calling buf.fill(fill).
+     *    If parameter is omitted, buffer will be filled with zeros.
+     * @param encoding encoding used for call to buf.fill while initalizing
+     */
+    static alloc(size: number, fill?: string | Buffer | number, encoding?: string): Buffer;
+    /**
+     * Allocates a new buffer of {size} octets, leaving memory not initialized, so the contents
+     * of the newly created Buffer are unknown and may contain sensitive data.
+     *
+     * @param size count of octets to allocate
+     */
+    static allocUnsafe(size: number): Buffer;
+    /**
+     * Allocates a new non-pooled buffer of {size} octets, leaving memory not initialized, so the contents
+     * of the newly created Buffer are unknown and may contain sensitive data.
+     *
+     * @param size count of octets to allocate
+     */
+    static allocUnsafeSlow(size: number): Buffer;
+  }
+}
\ No newline at end of file
diff --git a/server/node_modules/safe-buffer/index.js b/server/node_modules/safe-buffer/index.js
new file mode 100644
index 0000000..f8d3ec9
--- /dev/null
+++ b/server/node_modules/safe-buffer/index.js
@@ -0,0 +1,65 @@
+/*! safe-buffer. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
+/* eslint-disable node/no-deprecated-api */
+var buffer = require('buffer')
+var Buffer = buffer.Buffer
+
+// alternative to using Object.keys for old browsers
+function copyProps (src, dst) {
+  for (var key in src) {
+    dst[key] = src[key]
+  }
+}
+if (Buffer.from && Buffer.alloc && Buffer.allocUnsafe && Buffer.allocUnsafeSlow) {
+  module.exports = buffer
+} else {
+  // Copy properties from require('buffer')
+  copyProps(buffer, exports)
+  exports.Buffer = SafeBuffer
+}
+
+function SafeBuffer (arg, encodingOrOffset, length) {
+  return Buffer(arg, encodingOrOffset, length)
+}
+
+SafeBuffer.prototype = Object.create(Buffer.prototype)
+
+// Copy static methods from Buffer
+copyProps(Buffer, SafeBuffer)
+
+SafeBuffer.from = function (arg, encodingOrOffset, length) {
+  if (typeof arg === 'number') {
+    throw new TypeError('Argument must not be a number')
+  }
+  return Buffer(arg, encodingOrOffset, length)
+}
+
+SafeBuffer.alloc = function (size, fill, encoding) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  var buf = Buffer(size)
+  if (fill !== undefined) {
+    if (typeof encoding === 'string') {
+      buf.fill(fill, encoding)
+    } else {
+      buf.fill(fill)
+    }
+  } else {
+    buf.fill(0)
+  }
+  return buf
+}
+
+SafeBuffer.allocUnsafe = function (size) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  return Buffer(size)
+}
+
+SafeBuffer.allocUnsafeSlow = function (size) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  return buffer.SlowBuffer(size)
+}
diff --git a/server/node_modules/safe-buffer/package.json b/server/node_modules/safe-buffer/package.json
new file mode 100644
index 0000000..f2869e2
--- /dev/null
+++ b/server/node_modules/safe-buffer/package.json
@@ -0,0 +1,51 @@
+{
+  "name": "safe-buffer",
+  "description": "Safer Node.js Buffer API",
+  "version": "5.2.1",
+  "author": {
+    "name": "Feross Aboukhadijeh",
+    "email": "feross@feross.org",
+    "url": "https://feross.org"
+  },
+  "bugs": {
+    "url": "https://github.com/feross/safe-buffer/issues"
+  },
+  "devDependencies": {
+    "standard": "*",
+    "tape": "^5.0.0"
+  },
+  "homepage": "https://github.com/feross/safe-buffer",
+  "keywords": [
+    "buffer",
+    "buffer allocate",
+    "node security",
+    "safe",
+    "safe-buffer",
+    "security",
+    "uninitialized"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/feross/safe-buffer.git"
+  },
+  "scripts": {
+    "test": "standard && tape test/*.js"
+  },
+  "funding": [
+    {
+      "type": "github",
+      "url": "https://github.com/sponsors/feross"
+    },
+    {
+      "type": "patreon",
+      "url": "https://www.patreon.com/feross"
+    },
+    {
+      "type": "consulting",
+      "url": "https://feross.org/support"
+    }
+  ]
+}
diff --git a/server/node_modules/safer-buffer/LICENSE b/server/node_modules/safer-buffer/LICENSE
new file mode 100644
index 0000000..4fe9e6f
--- /dev/null
+++ b/server/node_modules/safer-buffer/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018 Nikita Skovoroda <chalkerx@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/safer-buffer/Porting-Buffer.md b/server/node_modules/safer-buffer/Porting-Buffer.md
new file mode 100644
index 0000000..68d86ba
--- /dev/null
+++ b/server/node_modules/safer-buffer/Porting-Buffer.md
@@ -0,0 +1,268 @@
+# Porting to the Buffer.from/Buffer.alloc API
+
+<a id="overview"></a>
+## Overview
+
+- [Variant 1: Drop support for Node.js ≤ 4.4.x and 5.0.0 — 5.9.x.](#variant-1) (*recommended*)
+- [Variant 2: Use a polyfill](#variant-2)
+- [Variant 3: manual detection, with safeguards](#variant-3)
+
+### Finding problematic bits of code using grep
+
+Just run `grep -nrE '[^a-zA-Z](Slow)?Buffer\s*\(' --exclude-dir node_modules`.
+
+It will find all the potentially unsafe places in your own code (with some considerably unlikely
+exceptions).
+
+### Finding problematic bits of code using Node.js 8
+
+If you’re using Node.js ≥ 8.0.0 (which is recommended), Node.js exposes multiple options that help with finding the relevant pieces of code:
+
+- `--trace-warnings` will make Node.js show a stack trace for this warning and other warnings that are printed by Node.js.
+- `--trace-deprecation` does the same thing, but only for deprecation warnings.
+- `--pending-deprecation` will show more types of deprecation warnings. In particular, it will show the `Buffer()` deprecation warning, even on Node.js 8.
+
+You can set these flags using an environment variable:
+
+```console
+$ export NODE_OPTIONS='--trace-warnings --pending-deprecation'
+$ cat example.js
+'use strict';
+const foo = new Buffer('foo');
+$ node example.js
+(node:7147) [DEP0005] DeprecationWarning: The Buffer() and new Buffer() constructors are not recommended for use due to security and usability concerns. Please use the new Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() construction methods instead.
+    at showFlaggedDeprecation (buffer.js:127:13)
+    at new Buffer (buffer.js:148:3)
+    at Object.<anonymous> (/path/to/example.js:2:13)
+    [... more stack trace lines ...]
+```
+
+### Finding problematic bits of code using linters
+
+Eslint rules [no-buffer-constructor](https://eslint.org/docs/rules/no-buffer-constructor)
+or
+[node/no-deprecated-api](https://github.com/mysticatea/eslint-plugin-node/blob/master/docs/rules/no-deprecated-api.md)
+also find calls to deprecated `Buffer()` API. Those rules are included in some pre-sets.
+
+There is a drawback, though, that it doesn't always
+[work correctly](https://github.com/chalker/safer-buffer#why-not-safe-buffer) when `Buffer` is
+overriden e.g. with a polyfill, so recommended is a combination of this and some other method
+described above.
+
+<a id="variant-1"></a>
+## Variant 1: Drop support for Node.js ≤ 4.4.x and 5.0.0 — 5.9.x.
+
+This is the recommended solution nowadays that would imply only minimal overhead.
+
+The Node.js 5.x release line has been unsupported since July 2016, and the Node.js 4.x release line reaches its End of Life in April 2018 (→ [Schedule](https://github.com/nodejs/Release#release-schedule)). This means that these versions of Node.js will *not* receive any updates, even in case of security issues, so using these release lines should be avoided, if at all possible.
+
+What you would do in this case is to convert all `new Buffer()` or `Buffer()` calls to use `Buffer.alloc()` or `Buffer.from()`, in the following way:
+
+- For `new Buffer(number)`, replace it with `Buffer.alloc(number)`.
+- For `new Buffer(string)` (or `new Buffer(string, encoding)`), replace it with `Buffer.from(string)` (or `Buffer.from(string, encoding)`).
+- For all other combinations of arguments (these are much rarer), also replace `new Buffer(...arguments)` with `Buffer.from(...arguments)`.
+
+Note that `Buffer.alloc()` is also _faster_ on the current Node.js versions than
+`new Buffer(size).fill(0)`, which is what you would otherwise need to ensure zero-filling.
+
+Enabling eslint rule [no-buffer-constructor](https://eslint.org/docs/rules/no-buffer-constructor)
+or
+[node/no-deprecated-api](https://github.com/mysticatea/eslint-plugin-node/blob/master/docs/rules/no-deprecated-api.md)
+is recommended to avoid accidential unsafe Buffer API usage.
+
+There is also a [JSCodeshift codemod](https://github.com/joyeecheung/node-dep-codemod#dep005)
+for automatically migrating Buffer constructors to `Buffer.alloc()` or `Buffer.from()`.
+Note that it currently only works with cases where the arguments are literals or where the
+constructor is invoked with two arguments.
+
+_If you currently support those older Node.js versions and dropping them would be a semver-major change
+for you, or if you support older branches of your packages, consider using [Variant 2](#variant-2)
+or [Variant 3](#variant-3) on older branches, so people using those older branches will also receive
+the fix. That way, you will eradicate potential issues caused by unguarded Buffer API usage and
+your users will not observe a runtime deprecation warning when running your code on Node.js 10._
+
+<a id="variant-2"></a>
+## Variant 2: Use a polyfill
+
+Utilize [safer-buffer](https://www.npmjs.com/package/safer-buffer) as a polyfill to support older
+Node.js versions.
+
+You would take exacly the same steps as in [Variant 1](#variant-1), but with a polyfill
+`const Buffer = require('safer-buffer').Buffer` in all files where you use the new `Buffer` api.
+
+Make sure that you do not use old `new Buffer` API — in any files where the line above is added,
+using old `new Buffer()` API will _throw_. It will be easy to notice that in CI, though.
+
+Alternatively, you could use [buffer-from](https://www.npmjs.com/package/buffer-from) and/or
+[buffer-alloc](https://www.npmjs.com/package/buffer-alloc) [ponyfills](https://ponyfill.com/) —
+those are great, the only downsides being 4 deps in the tree and slightly more code changes to
+migrate off them (as you would be using e.g. `Buffer.from` under a different name). If you need only
+`Buffer.from` polyfilled — `buffer-from` alone which comes with no extra dependencies.
+
+_Alternatively, you could use [safe-buffer](https://www.npmjs.com/package/safe-buffer) — it also
+provides a polyfill, but takes a different approach which has
+[it's drawbacks](https://github.com/chalker/safer-buffer#why-not-safe-buffer). It will allow you
+to also use the older `new Buffer()` API in your code, though — but that's arguably a benefit, as
+it is problematic, can cause issues in your code, and will start emitting runtime deprecation
+warnings starting with Node.js 10._
+
+Note that in either case, it is important that you also remove all calls to the old Buffer
+API manually — just throwing in `safe-buffer` doesn't fix the problem by itself, it just provides
+a polyfill for the new API. I have seen people doing that mistake.
+
+Enabling eslint rule [no-buffer-constructor](https://eslint.org/docs/rules/no-buffer-constructor)
+or
+[node/no-deprecated-api](https://github.com/mysticatea/eslint-plugin-node/blob/master/docs/rules/no-deprecated-api.md)
+is recommended.
+
+_Don't forget to drop the polyfill usage once you drop support for Node.js < 4.5.0._
+
+<a id="variant-3"></a>
+## Variant 3 — manual detection, with safeguards
+
+This is useful if you create Buffer instances in only a few places (e.g. one), or you have your own
+wrapper around them.
+
+### Buffer(0)
+
+This special case for creating empty buffers can be safely replaced with `Buffer.concat([])`, which
+returns the same result all the way down to Node.js 0.8.x.
+
+### Buffer(notNumber)
+
+Before:
+
+```js
+var buf = new Buffer(notNumber, encoding);
+```
+
+After:
+
+```js
+var buf;
+if (Buffer.from && Buffer.from !== Uint8Array.from) {
+  buf = Buffer.from(notNumber, encoding);
+} else {
+  if (typeof notNumber === 'number')
+    throw new Error('The "size" argument must be of type number.');
+  buf = new Buffer(notNumber, encoding);
+}
+```
+
+`encoding` is optional.
+
+Note that the `typeof notNumber` before `new Buffer` is required (for cases when `notNumber` argument is not
+hard-coded) and _is not caused by the deprecation of Buffer constructor_ — it's exactly _why_ the
+Buffer constructor is deprecated. Ecosystem packages lacking this type-check caused numereous
+security issues — situations when unsanitized user input could end up in the `Buffer(arg)` create
+problems ranging from DoS to leaking sensitive information to the attacker from the process memory.
+
+When `notNumber` argument is hardcoded (e.g. literal `"abc"` or `[0,1,2]`), the `typeof` check can
+be omitted.
+
+Also note that using TypeScript does not fix this problem for you — when libs written in
+`TypeScript` are used from JS, or when user input ends up there — it behaves exactly as pure JS, as
+all type checks are translation-time only and are not present in the actual JS code which TS
+compiles to.
+
+### Buffer(number)
+
+For Node.js 0.10.x (and below) support:
+
+```js
+var buf;
+if (Buffer.alloc) {
+  buf = Buffer.alloc(number);
+} else {
+  buf = new Buffer(number);
+  buf.fill(0);
+}
+```
+
+Otherwise (Node.js ≥ 0.12.x):
+
+```js
+const buf = Buffer.alloc ? Buffer.alloc(number) : new Buffer(number).fill(0);
+```
+
+## Regarding Buffer.allocUnsafe
+
+Be extra cautious when using `Buffer.allocUnsafe`:
+ * Don't use it if you don't have a good reason to
+   * e.g. you probably won't ever see a performance difference for small buffers, in fact, those
+     might be even faster with `Buffer.alloc()`,
+   * if your code is not in the hot code path — you also probably won't notice a difference,
+   * keep in mind that zero-filling minimizes the potential risks.
+ * If you use it, make sure that you never return the buffer in a partially-filled state,
+   * if you are writing to it sequentially — always truncate it to the actuall written length
+
+Errors in handling buffers allocated with `Buffer.allocUnsafe` could result in various issues,
+ranged from undefined behaviour of your code to sensitive data (user input, passwords, certs)
+leaking to the remote attacker.
+
+_Note that the same applies to `new Buffer` usage without zero-filling, depending on the Node.js
+version (and lacking type checks also adds DoS to the list of potential problems)._
+
+<a id="faq"></a>
+## FAQ
+
+<a id="design-flaws"></a>
+### What is wrong with the `Buffer` constructor?
+
+The `Buffer` constructor could be used to create a buffer in many different ways:
+
+- `new Buffer(42)` creates a `Buffer` of 42 bytes. Before Node.js 8, this buffer contained
+  *arbitrary memory* for performance reasons, which could include anything ranging from
+  program source code to passwords and encryption keys.
+- `new Buffer('abc')` creates a `Buffer` that contains the UTF-8-encoded version of
+  the string `'abc'`. A second argument could specify another encoding: For example,
+  `new Buffer(string, 'base64')` could be used to convert a Base64 string into the original
+  sequence of bytes that it represents.
+- There are several other combinations of arguments.
+
+This meant that, in code like `var buffer = new Buffer(foo);`, *it is not possible to tell
+what exactly the contents of the generated buffer are* without knowing the type of `foo`.
+
+Sometimes, the value of `foo` comes from an external source. For example, this function
+could be exposed as a service on a web server, converting a UTF-8 string into its Base64 form:
+
+```
+function stringToBase64(req, res) {
+  // The request body should have the format of `{ string: 'foobar' }`
+  const rawBytes = new Buffer(req.body.string)
+  const encoded = rawBytes.toString('base64')
+  res.end({ encoded: encoded })
+}
+```
+
+Note that this code does *not* validate the type of `req.body.string`:
+
+- `req.body.string` is expected to be a string. If this is the case, all goes well.
+- `req.body.string` is controlled by the client that sends the request.
+- If `req.body.string` is the *number* `50`, the `rawBytes` would be 50 bytes:
+  - Before Node.js 8, the content would be uninitialized
+  - After Node.js 8, the content would be `50` bytes with the value `0`
+
+Because of the missing type check, an attacker could intentionally send a number
+as part of the request. Using this, they can either:
+
+- Read uninitialized memory. This **will** leak passwords, encryption keys and other
+  kinds of sensitive information. (Information leak)
+- Force the program to allocate a large amount of memory. For example, when specifying
+  `500000000` as the input value, each request will allocate 500MB of memory.
+  This can be used to either exhaust the memory available of a program completely
+  and make it crash, or slow it down significantly. (Denial of Service)
+
+Both of these scenarios are considered serious security issues in a real-world
+web server context.
+
+when using `Buffer.from(req.body.string)` instead, passing a number will always
+throw an exception instead, giving a controlled behaviour that can always be
+handled by the program.
+
+<a id="ecosystem-usage"></a>
+### The `Buffer()` constructor has been deprecated for a while. Is this really an issue?
+
+Surveys of code in the `npm` ecosystem have shown that the `Buffer()` constructor is still
+widely used. This includes new code, and overall usage of such code has actually been
+*increasing*.
diff --git a/server/node_modules/safer-buffer/Readme.md b/server/node_modules/safer-buffer/Readme.md
new file mode 100644
index 0000000..14b0822
--- /dev/null
+++ b/server/node_modules/safer-buffer/Readme.md
@@ -0,0 +1,156 @@
+# safer-buffer [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![javascript style guide][standard-image]][standard-url] [![Security Responsible Disclosure][secuirty-image]][secuirty-url]
+
+[travis-image]: https://travis-ci.org/ChALkeR/safer-buffer.svg?branch=master
+[travis-url]: https://travis-ci.org/ChALkeR/safer-buffer
+[npm-image]: https://img.shields.io/npm/v/safer-buffer.svg
+[npm-url]: https://npmjs.org/package/safer-buffer
+[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
+[standard-url]: https://standardjs.com
+[secuirty-image]: https://img.shields.io/badge/Security-Responsible%20Disclosure-green.svg
+[secuirty-url]: https://github.com/nodejs/security-wg/blob/master/processes/responsible_disclosure_template.md
+
+Modern Buffer API polyfill without footguns, working on Node.js from 0.8 to current.
+
+## How to use?
+
+First, port all `Buffer()` and `new Buffer()` calls to `Buffer.alloc()` and `Buffer.from()` API.
+
+Then, to achieve compatibility with outdated Node.js versions (`<4.5.0` and 5.x `<5.9.0`), use
+`const Buffer = require('safer-buffer').Buffer` in all files where you make calls to the new
+Buffer API. _Use `var` instead of `const` if you need that for your Node.js version range support._
+
+Also, see the
+[porting Buffer](https://github.com/ChALkeR/safer-buffer/blob/master/Porting-Buffer.md) guide.
+
+## Do I need it?
+
+Hopefully, not — dropping support for outdated Node.js versions should be fine nowdays, and that
+is the recommended path forward. You _do_ need to port to the `Buffer.alloc()` and `Buffer.from()`
+though.
+
+See the [porting guide](https://github.com/ChALkeR/safer-buffer/blob/master/Porting-Buffer.md)
+for a better description.
+
+## Why not [safe-buffer](https://npmjs.com/safe-buffer)?
+
+_In short: while `safe-buffer` serves as a polyfill for the new API, it allows old API usage and
+itself contains footguns._
+
+`safe-buffer` could be used safely to get the new API while still keeping support for older
+Node.js versions (like this module), but while analyzing ecosystem usage of the old Buffer API
+I found out that `safe-buffer` is itself causing problems in some cases.
+
+For example, consider the following snippet:
+
+```console
+$ cat example.unsafe.js
+console.log(Buffer(20))
+$ ./node-v6.13.0-linux-x64/bin/node example.unsafe.js
+<Buffer 0a 00 00 00 00 00 00 00 28 13 de 02 00 00 00 00 05 00 00 00>
+$ standard example.unsafe.js
+standard: Use JavaScript Standard Style (https://standardjs.com)
+  /home/chalker/repo/safer-buffer/example.unsafe.js:2:13: 'Buffer()' was deprecated since v6. Use 'Buffer.alloc()' or 'Buffer.from()' (use 'https://www.npmjs.com/package/safe-buffer' for '<4.5.0') instead.
+```
+
+This is allocates and writes to console an uninitialized chunk of memory.
+[standard](https://www.npmjs.com/package/standard) linter (among others) catch that and warn people
+to avoid using unsafe API.
+
+Let's now throw in `safe-buffer`!
+
+```console
+$ cat example.safe-buffer.js
+const Buffer = require('safe-buffer').Buffer
+console.log(Buffer(20))
+$ standard example.safe-buffer.js
+$ ./node-v6.13.0-linux-x64/bin/node example.safe-buffer.js
+<Buffer 08 00 00 00 00 00 00 00 28 58 01 82 fe 7f 00 00 00 00 00 00>
+```
+
+See the problem? Adding in `safe-buffer` _magically removes the lint warning_, but the behavior
+remains identiсal to what we had before, and when launched on Node.js 6.x LTS — this dumps out
+chunks of uninitialized memory.
+_And this code will still emit runtime warnings on Node.js 10.x and above._
+
+That was done by design. I first considered changing `safe-buffer`, prohibiting old API usage or
+emitting warnings on it, but that significantly diverges from `safe-buffer` design. After some
+discussion, it was decided to move my approach into a separate package, and _this is that separate
+package_.
+
+This footgun is not imaginary — I observed top-downloaded packages doing that kind of thing,
+«fixing» the lint warning by blindly including `safe-buffer` without any actual changes.
+
+Also in some cases, even if the API _was_ migrated to use of safe Buffer API — a random pull request
+can bring unsafe Buffer API usage back to the codebase by adding new calls — and that could go
+unnoticed even if you have a linter prohibiting that (becase of the reason stated above), and even
+pass CI. _I also observed that being done in popular packages._
+
+Some examples:
+ * [webdriverio](https://github.com/webdriverio/webdriverio/commit/05cbd3167c12e4930f09ef7cf93b127ba4effae4#diff-124380949022817b90b622871837d56cR31)
+   (a module with 548 759 downloads/month),
+ * [websocket-stream](https://github.com/maxogden/websocket-stream/commit/c9312bd24d08271687d76da0fe3c83493871cf61)
+   (218 288 d/m, fix in [maxogden/websocket-stream#142](https://github.com/maxogden/websocket-stream/pull/142)),
+ * [node-serialport](https://github.com/node-serialport/node-serialport/commit/e8d9d2b16c664224920ce1c895199b1ce2def48c)
+   (113 138 d/m, fix in [node-serialport/node-serialport#1510](https://github.com/node-serialport/node-serialport/pull/1510)),
+ * [karma](https://github.com/karma-runner/karma/commit/3d94b8cf18c695104ca195334dc75ff054c74eec)
+   (3 973 193 d/m, fix in [karma-runner/karma#2947](https://github.com/karma-runner/karma/pull/2947)),
+ * [spdy-transport](https://github.com/spdy-http2/spdy-transport/commit/5375ac33f4a62a4f65bcfc2827447d42a5dbe8b1)
+   (5 970 727 d/m, fix in [spdy-http2/spdy-transport#53](https://github.com/spdy-http2/spdy-transport/pull/53)).
+ * And there are a lot more over the ecosystem.
+
+I filed a PR at
+[mysticatea/eslint-plugin-node#110](https://github.com/mysticatea/eslint-plugin-node/pull/110) to
+partially fix that (for cases when that lint rule is used), but it is a semver-major change for
+linter rules and presets, so it would take significant time for that to reach actual setups.
+_It also hasn't been released yet (2018-03-20)._
+
+Also, `safer-buffer` discourages the usage of `.allocUnsafe()`, which is often done by a mistake.
+It still supports it with an explicit concern barier, by placing it under
+`require('safer-buffer/dangereous')`.
+
+## But isn't throwing bad?
+
+Not really. It's an error that could be noticed and fixed early, instead of causing havoc later like
+unguarded `new Buffer()` calls that end up receiving user input can do.
+
+This package affects only the files where `var Buffer = require('safer-buffer').Buffer` was done, so
+it is really simple to keep track of things and make sure that you don't mix old API usage with that.
+Also, CI should hint anything that you might have missed.
+
+New commits, if tested, won't land new usage of unsafe Buffer API this way.
+_Node.js 10.x also deals with that by printing a runtime depecation warning._
+
+### Would it affect third-party modules?
+
+No, unless you explicitly do an awful thing like monkey-patching or overriding the built-in `Buffer`.
+Don't do that.
+
+### But I don't want throwing…
+
+That is also fine!
+
+Also, it could be better in some cases when you don't comprehensive enough test coverage.
+
+In that case — just don't override `Buffer` and use
+`var SaferBuffer = require('safer-buffer').Buffer` instead.
+
+That way, everything using `Buffer` natively would still work, but there would be two drawbacks:
+
+* `Buffer.from`/`Buffer.alloc` won't be polyfilled — use `SaferBuffer.from` and
+  `SaferBuffer.alloc` instead.
+* You are still open to accidentally using the insecure deprecated API — use a linter to catch that.
+
+Note that using a linter to catch accidential `Buffer` constructor usage in this case is strongly
+recommended. `Buffer` is not overriden in this usecase, so linters won't get confused.
+
+## «Without footguns»?
+
+Well, it is still possible to do _some_ things with `Buffer` API, e.g. accessing `.buffer` property
+on older versions and duping things from there. You shouldn't do that in your code, probabably.
+
+The intention is to remove the most significant footguns that affect lots of packages in the
+ecosystem, and to do it in the proper way.
+
+Also, this package doesn't protect against security issues affecting some Node.js versions, so for
+usage in your own production code, it is still recommended to update to a Node.js version
+[supported by upstream](https://github.com/nodejs/release#release-schedule).
diff --git a/server/node_modules/safer-buffer/dangerous.js b/server/node_modules/safer-buffer/dangerous.js
new file mode 100644
index 0000000..ca41fdc
--- /dev/null
+++ b/server/node_modules/safer-buffer/dangerous.js
@@ -0,0 +1,58 @@
+/* eslint-disable node/no-deprecated-api */
+
+'use strict'
+
+var buffer = require('buffer')
+var Buffer = buffer.Buffer
+var safer = require('./safer.js')
+var Safer = safer.Buffer
+
+var dangerous = {}
+
+var key
+
+for (key in safer) {
+  if (!safer.hasOwnProperty(key)) continue
+  dangerous[key] = safer[key]
+}
+
+var Dangereous = dangerous.Buffer = {}
+
+// Copy Safer API
+for (key in Safer) {
+  if (!Safer.hasOwnProperty(key)) continue
+  Dangereous[key] = Safer[key]
+}
+
+// Copy those missing unsafe methods, if they are present
+for (key in Buffer) {
+  if (!Buffer.hasOwnProperty(key)) continue
+  if (Dangereous.hasOwnProperty(key)) continue
+  Dangereous[key] = Buffer[key]
+}
+
+if (!Dangereous.allocUnsafe) {
+  Dangereous.allocUnsafe = function (size) {
+    if (typeof size !== 'number') {
+      throw new TypeError('The "size" argument must be of type number. Received type ' + typeof size)
+    }
+    if (size < 0 || size >= 2 * (1 << 30)) {
+      throw new RangeError('The value "' + size + '" is invalid for option "size"')
+    }
+    return Buffer(size)
+  }
+}
+
+if (!Dangereous.allocUnsafeSlow) {
+  Dangereous.allocUnsafeSlow = function (size) {
+    if (typeof size !== 'number') {
+      throw new TypeError('The "size" argument must be of type number. Received type ' + typeof size)
+    }
+    if (size < 0 || size >= 2 * (1 << 30)) {
+      throw new RangeError('The value "' + size + '" is invalid for option "size"')
+    }
+    return buffer.SlowBuffer(size)
+  }
+}
+
+module.exports = dangerous
diff --git a/server/node_modules/safer-buffer/package.json b/server/node_modules/safer-buffer/package.json
new file mode 100644
index 0000000..d452b04
--- /dev/null
+++ b/server/node_modules/safer-buffer/package.json
@@ -0,0 +1,34 @@
+{
+  "name": "safer-buffer",
+  "version": "2.1.2",
+  "description": "Modern Buffer API polyfill without footguns",
+  "main": "safer.js",
+  "scripts": {
+    "browserify-test": "browserify --external tape tests.js > browserify-tests.js && tape browserify-tests.js",
+    "test": "standard && tape tests.js"
+  },
+  "author": {
+    "name": "Nikita Skovoroda",
+    "email": "chalkerx@gmail.com",
+    "url": "https://github.com/ChALkeR"
+  },
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/ChALkeR/safer-buffer.git"
+  },
+  "bugs": {
+    "url": "https://github.com/ChALkeR/safer-buffer/issues"
+  },
+  "devDependencies": {
+    "standard": "^11.0.1",
+    "tape": "^4.9.0"
+  },
+  "files": [
+    "Porting-Buffer.md",
+    "Readme.md",
+    "tests.js",
+    "dangerous.js",
+    "safer.js"
+  ]
+}
diff --git a/server/node_modules/safer-buffer/safer.js b/server/node_modules/safer-buffer/safer.js
new file mode 100644
index 0000000..37c7e1a
--- /dev/null
+++ b/server/node_modules/safer-buffer/safer.js
@@ -0,0 +1,77 @@
+/* eslint-disable node/no-deprecated-api */
+
+'use strict'
+
+var buffer = require('buffer')
+var Buffer = buffer.Buffer
+
+var safer = {}
+
+var key
+
+for (key in buffer) {
+  if (!buffer.hasOwnProperty(key)) continue
+  if (key === 'SlowBuffer' || key === 'Buffer') continue
+  safer[key] = buffer[key]
+}
+
+var Safer = safer.Buffer = {}
+for (key in Buffer) {
+  if (!Buffer.hasOwnProperty(key)) continue
+  if (key === 'allocUnsafe' || key === 'allocUnsafeSlow') continue
+  Safer[key] = Buffer[key]
+}
+
+safer.Buffer.prototype = Buffer.prototype
+
+if (!Safer.from || Safer.from === Uint8Array.from) {
+  Safer.from = function (value, encodingOrOffset, length) {
+    if (typeof value === 'number') {
+      throw new TypeError('The "value" argument must not be of type number. Received type ' + typeof value)
+    }
+    if (value && typeof value.length === 'undefined') {
+      throw new TypeError('The first argument must be one of type string, Buffer, ArrayBuffer, Array, or Array-like Object. Received type ' + typeof value)
+    }
+    return Buffer(value, encodingOrOffset, length)
+  }
+}
+
+if (!Safer.alloc) {
+  Safer.alloc = function (size, fill, encoding) {
+    if (typeof size !== 'number') {
+      throw new TypeError('The "size" argument must be of type number. Received type ' + typeof size)
+    }
+    if (size < 0 || size >= 2 * (1 << 30)) {
+      throw new RangeError('The value "' + size + '" is invalid for option "size"')
+    }
+    var buf = Buffer(size)
+    if (!fill || fill.length === 0) {
+      buf.fill(0)
+    } else if (typeof encoding === 'string') {
+      buf.fill(fill, encoding)
+    } else {
+      buf.fill(fill)
+    }
+    return buf
+  }
+}
+
+if (!safer.kStringMaxLength) {
+  try {
+    safer.kStringMaxLength = process.binding('buffer').kStringMaxLength
+  } catch (e) {
+    // we can't determine kStringMaxLength in environments where process.binding
+    // is unsupported, so let's not set it
+  }
+}
+
+if (!safer.constants) {
+  safer.constants = {
+    MAX_LENGTH: safer.kMaxLength
+  }
+  if (safer.kStringMaxLength) {
+    safer.constants.MAX_STRING_LENGTH = safer.kStringMaxLength
+  }
+}
+
+module.exports = safer
diff --git a/server/node_modules/safer-buffer/tests.js b/server/node_modules/safer-buffer/tests.js
new file mode 100644
index 0000000..7ed2777
--- /dev/null
+++ b/server/node_modules/safer-buffer/tests.js
@@ -0,0 +1,406 @@
+/* eslint-disable node/no-deprecated-api */
+
+'use strict'
+
+var test = require('tape')
+
+var buffer = require('buffer')
+
+var index = require('./')
+var safer = require('./safer')
+var dangerous = require('./dangerous')
+
+/* Inheritance tests */
+
+test('Default is Safer', function (t) {
+  t.equal(index, safer)
+  t.notEqual(safer, dangerous)
+  t.notEqual(index, dangerous)
+  t.end()
+})
+
+test('Is not a function', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.equal(typeof impl, 'object')
+    t.equal(typeof impl.Buffer, 'object')
+  });
+  [buffer].forEach(function (impl) {
+    t.equal(typeof impl, 'object')
+    t.equal(typeof impl.Buffer, 'function')
+  })
+  t.end()
+})
+
+test('Constructor throws', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.throws(function () { impl.Buffer() })
+    t.throws(function () { impl.Buffer(0) })
+    t.throws(function () { impl.Buffer('a') })
+    t.throws(function () { impl.Buffer('a', 'utf-8') })
+    t.throws(function () { return new impl.Buffer() })
+    t.throws(function () { return new impl.Buffer(0) })
+    t.throws(function () { return new impl.Buffer('a') })
+    t.throws(function () { return new impl.Buffer('a', 'utf-8') })
+  })
+  t.end()
+})
+
+test('Safe methods exist', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.equal(typeof impl.Buffer.alloc, 'function', 'alloc')
+    t.equal(typeof impl.Buffer.from, 'function', 'from')
+  })
+  t.end()
+})
+
+test('Unsafe methods exist only in Dangerous', function (t) {
+  [index, safer].forEach(function (impl) {
+    t.equal(typeof impl.Buffer.allocUnsafe, 'undefined')
+    t.equal(typeof impl.Buffer.allocUnsafeSlow, 'undefined')
+  });
+  [dangerous].forEach(function (impl) {
+    t.equal(typeof impl.Buffer.allocUnsafe, 'function')
+    t.equal(typeof impl.Buffer.allocUnsafeSlow, 'function')
+  })
+  t.end()
+})
+
+test('Generic methods/properties are defined and equal', function (t) {
+  ['poolSize', 'isBuffer', 'concat', 'byteLength'].forEach(function (method) {
+    [index, safer, dangerous].forEach(function (impl) {
+      t.equal(impl.Buffer[method], buffer.Buffer[method], method)
+      t.notEqual(typeof impl.Buffer[method], 'undefined', method)
+    })
+  })
+  t.end()
+})
+
+test('Built-in buffer static methods/properties are inherited', function (t) {
+  Object.keys(buffer).forEach(function (method) {
+    if (method === 'SlowBuffer' || method === 'Buffer') return;
+    [index, safer, dangerous].forEach(function (impl) {
+      t.equal(impl[method], buffer[method], method)
+      t.notEqual(typeof impl[method], 'undefined', method)
+    })
+  })
+  t.end()
+})
+
+test('Built-in Buffer static methods/properties are inherited', function (t) {
+  Object.keys(buffer.Buffer).forEach(function (method) {
+    if (method === 'allocUnsafe' || method === 'allocUnsafeSlow') return;
+    [index, safer, dangerous].forEach(function (impl) {
+      t.equal(impl.Buffer[method], buffer.Buffer[method], method)
+      t.notEqual(typeof impl.Buffer[method], 'undefined', method)
+    })
+  })
+  t.end()
+})
+
+test('.prototype property of Buffer is inherited', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.equal(impl.Buffer.prototype, buffer.Buffer.prototype, 'prototype')
+    t.notEqual(typeof impl.Buffer.prototype, 'undefined', 'prototype')
+  })
+  t.end()
+})
+
+test('All Safer methods are present in Dangerous', function (t) {
+  Object.keys(safer).forEach(function (method) {
+    if (method === 'Buffer') return;
+    [index, safer, dangerous].forEach(function (impl) {
+      t.equal(impl[method], safer[method], method)
+      if (method !== 'kStringMaxLength') {
+        t.notEqual(typeof impl[method], 'undefined', method)
+      }
+    })
+  })
+  Object.keys(safer.Buffer).forEach(function (method) {
+    [index, safer, dangerous].forEach(function (impl) {
+      t.equal(impl.Buffer[method], safer.Buffer[method], method)
+      t.notEqual(typeof impl.Buffer[method], 'undefined', method)
+    })
+  })
+  t.end()
+})
+
+test('Safe methods from Dangerous methods are present in Safer', function (t) {
+  Object.keys(dangerous).forEach(function (method) {
+    if (method === 'Buffer') return;
+    [index, safer, dangerous].forEach(function (impl) {
+      t.equal(impl[method], dangerous[method], method)
+      if (method !== 'kStringMaxLength') {
+        t.notEqual(typeof impl[method], 'undefined', method)
+      }
+    })
+  })
+  Object.keys(dangerous.Buffer).forEach(function (method) {
+    if (method === 'allocUnsafe' || method === 'allocUnsafeSlow') return;
+    [index, safer, dangerous].forEach(function (impl) {
+      t.equal(impl.Buffer[method], dangerous.Buffer[method], method)
+      t.notEqual(typeof impl.Buffer[method], 'undefined', method)
+    })
+  })
+  t.end()
+})
+
+/* Behaviour tests */
+
+test('Methods return Buffers', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.alloc(0)))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.alloc(0, 10)))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.alloc(0, 'a')))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.alloc(10)))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.alloc(10, 'x')))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.alloc(9, 'ab')))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.from('')))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.from('string')))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.from('string', 'utf-8')))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.from('b25ldHdvdGhyZWU=', 'base64')))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.from([0, 42, 3])))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.from(new Uint8Array([0, 42, 3]))))
+    t.ok(buffer.Buffer.isBuffer(impl.Buffer.from([])))
+  });
+  ['allocUnsafe', 'allocUnsafeSlow'].forEach(function (method) {
+    t.ok(buffer.Buffer.isBuffer(dangerous.Buffer[method](0)))
+    t.ok(buffer.Buffer.isBuffer(dangerous.Buffer[method](10)))
+  })
+  t.end()
+})
+
+test('Constructor is buffer.Buffer', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.equal(impl.Buffer.alloc(0).constructor, buffer.Buffer)
+    t.equal(impl.Buffer.alloc(0, 10).constructor, buffer.Buffer)
+    t.equal(impl.Buffer.alloc(0, 'a').constructor, buffer.Buffer)
+    t.equal(impl.Buffer.alloc(10).constructor, buffer.Buffer)
+    t.equal(impl.Buffer.alloc(10, 'x').constructor, buffer.Buffer)
+    t.equal(impl.Buffer.alloc(9, 'ab').constructor, buffer.Buffer)
+    t.equal(impl.Buffer.from('').constructor, buffer.Buffer)
+    t.equal(impl.Buffer.from('string').constructor, buffer.Buffer)
+    t.equal(impl.Buffer.from('string', 'utf-8').constructor, buffer.Buffer)
+    t.equal(impl.Buffer.from('b25ldHdvdGhyZWU=', 'base64').constructor, buffer.Buffer)
+    t.equal(impl.Buffer.from([0, 42, 3]).constructor, buffer.Buffer)
+    t.equal(impl.Buffer.from(new Uint8Array([0, 42, 3])).constructor, buffer.Buffer)
+    t.equal(impl.Buffer.from([]).constructor, buffer.Buffer)
+  });
+  [0, 10, 100].forEach(function (arg) {
+    t.equal(dangerous.Buffer.allocUnsafe(arg).constructor, buffer.Buffer)
+    t.equal(dangerous.Buffer.allocUnsafeSlow(arg).constructor, buffer.SlowBuffer(0).constructor)
+  })
+  t.end()
+})
+
+test('Invalid calls throw', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.throws(function () { impl.Buffer.from(0) })
+    t.throws(function () { impl.Buffer.from(10) })
+    t.throws(function () { impl.Buffer.from(10, 'utf-8') })
+    t.throws(function () { impl.Buffer.from('string', 'invalid encoding') })
+    t.throws(function () { impl.Buffer.from(-10) })
+    t.throws(function () { impl.Buffer.from(1e90) })
+    t.throws(function () { impl.Buffer.from(Infinity) })
+    t.throws(function () { impl.Buffer.from(-Infinity) })
+    t.throws(function () { impl.Buffer.from(NaN) })
+    t.throws(function () { impl.Buffer.from(null) })
+    t.throws(function () { impl.Buffer.from(undefined) })
+    t.throws(function () { impl.Buffer.from() })
+    t.throws(function () { impl.Buffer.from({}) })
+    t.throws(function () { impl.Buffer.alloc('') })
+    t.throws(function () { impl.Buffer.alloc('string') })
+    t.throws(function () { impl.Buffer.alloc('string', 'utf-8') })
+    t.throws(function () { impl.Buffer.alloc('b25ldHdvdGhyZWU=', 'base64') })
+    t.throws(function () { impl.Buffer.alloc(-10) })
+    t.throws(function () { impl.Buffer.alloc(1e90) })
+    t.throws(function () { impl.Buffer.alloc(2 * (1 << 30)) })
+    t.throws(function () { impl.Buffer.alloc(Infinity) })
+    t.throws(function () { impl.Buffer.alloc(-Infinity) })
+    t.throws(function () { impl.Buffer.alloc(null) })
+    t.throws(function () { impl.Buffer.alloc(undefined) })
+    t.throws(function () { impl.Buffer.alloc() })
+    t.throws(function () { impl.Buffer.alloc([]) })
+    t.throws(function () { impl.Buffer.alloc([0, 42, 3]) })
+    t.throws(function () { impl.Buffer.alloc({}) })
+  });
+  ['allocUnsafe', 'allocUnsafeSlow'].forEach(function (method) {
+    t.throws(function () { dangerous.Buffer[method]('') })
+    t.throws(function () { dangerous.Buffer[method]('string') })
+    t.throws(function () { dangerous.Buffer[method]('string', 'utf-8') })
+    t.throws(function () { dangerous.Buffer[method](2 * (1 << 30)) })
+    t.throws(function () { dangerous.Buffer[method](Infinity) })
+    if (dangerous.Buffer[method] === buffer.Buffer.allocUnsafe) {
+      t.skip('Skipping, older impl of allocUnsafe coerced negative sizes to 0')
+    } else {
+      t.throws(function () { dangerous.Buffer[method](-10) })
+      t.throws(function () { dangerous.Buffer[method](-1e90) })
+      t.throws(function () { dangerous.Buffer[method](-Infinity) })
+    }
+    t.throws(function () { dangerous.Buffer[method](null) })
+    t.throws(function () { dangerous.Buffer[method](undefined) })
+    t.throws(function () { dangerous.Buffer[method]() })
+    t.throws(function () { dangerous.Buffer[method]([]) })
+    t.throws(function () { dangerous.Buffer[method]([0, 42, 3]) })
+    t.throws(function () { dangerous.Buffer[method]({}) })
+  })
+  t.end()
+})
+
+test('Buffers have appropriate lengths', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.equal(impl.Buffer.alloc(0).length, 0)
+    t.equal(impl.Buffer.alloc(10).length, 10)
+    t.equal(impl.Buffer.from('').length, 0)
+    t.equal(impl.Buffer.from('string').length, 6)
+    t.equal(impl.Buffer.from('string', 'utf-8').length, 6)
+    t.equal(impl.Buffer.from('b25ldHdvdGhyZWU=', 'base64').length, 11)
+    t.equal(impl.Buffer.from([0, 42, 3]).length, 3)
+    t.equal(impl.Buffer.from(new Uint8Array([0, 42, 3])).length, 3)
+    t.equal(impl.Buffer.from([]).length, 0)
+  });
+  ['allocUnsafe', 'allocUnsafeSlow'].forEach(function (method) {
+    t.equal(dangerous.Buffer[method](0).length, 0)
+    t.equal(dangerous.Buffer[method](10).length, 10)
+  })
+  t.end()
+})
+
+test('Buffers have appropriate lengths (2)', function (t) {
+  t.equal(index.Buffer.alloc, safer.Buffer.alloc)
+  t.equal(index.Buffer.alloc, dangerous.Buffer.alloc)
+  var ok = true;
+  [ safer.Buffer.alloc,
+    dangerous.Buffer.allocUnsafe,
+    dangerous.Buffer.allocUnsafeSlow
+  ].forEach(function (method) {
+    for (var i = 0; i < 1e2; i++) {
+      var length = Math.round(Math.random() * 1e5)
+      var buf = method(length)
+      if (!buffer.Buffer.isBuffer(buf)) ok = false
+      if (buf.length !== length) ok = false
+    }
+  })
+  t.ok(ok)
+  t.end()
+})
+
+test('.alloc(size) is zero-filled and has correct length', function (t) {
+  t.equal(index.Buffer.alloc, safer.Buffer.alloc)
+  t.equal(index.Buffer.alloc, dangerous.Buffer.alloc)
+  var ok = true
+  for (var i = 0; i < 1e2; i++) {
+    var length = Math.round(Math.random() * 2e6)
+    var buf = index.Buffer.alloc(length)
+    if (!buffer.Buffer.isBuffer(buf)) ok = false
+    if (buf.length !== length) ok = false
+    var j
+    for (j = 0; j < length; j++) {
+      if (buf[j] !== 0) ok = false
+    }
+    buf.fill(1)
+    for (j = 0; j < length; j++) {
+      if (buf[j] !== 1) ok = false
+    }
+  }
+  t.ok(ok)
+  t.end()
+})
+
+test('.allocUnsafe / .allocUnsafeSlow are fillable and have correct lengths', function (t) {
+  ['allocUnsafe', 'allocUnsafeSlow'].forEach(function (method) {
+    var ok = true
+    for (var i = 0; i < 1e2; i++) {
+      var length = Math.round(Math.random() * 2e6)
+      var buf = dangerous.Buffer[method](length)
+      if (!buffer.Buffer.isBuffer(buf)) ok = false
+      if (buf.length !== length) ok = false
+      buf.fill(0, 0, length)
+      var j
+      for (j = 0; j < length; j++) {
+        if (buf[j] !== 0) ok = false
+      }
+      buf.fill(1, 0, length)
+      for (j = 0; j < length; j++) {
+        if (buf[j] !== 1) ok = false
+      }
+    }
+    t.ok(ok, method)
+  })
+  t.end()
+})
+
+test('.alloc(size, fill) is `fill`-filled', function (t) {
+  t.equal(index.Buffer.alloc, safer.Buffer.alloc)
+  t.equal(index.Buffer.alloc, dangerous.Buffer.alloc)
+  var ok = true
+  for (var i = 0; i < 1e2; i++) {
+    var length = Math.round(Math.random() * 2e6)
+    var fill = Math.round(Math.random() * 255)
+    var buf = index.Buffer.alloc(length, fill)
+    if (!buffer.Buffer.isBuffer(buf)) ok = false
+    if (buf.length !== length) ok = false
+    for (var j = 0; j < length; j++) {
+      if (buf[j] !== fill) ok = false
+    }
+  }
+  t.ok(ok)
+  t.end()
+})
+
+test('.alloc(size, fill) is `fill`-filled', function (t) {
+  t.equal(index.Buffer.alloc, safer.Buffer.alloc)
+  t.equal(index.Buffer.alloc, dangerous.Buffer.alloc)
+  var ok = true
+  for (var i = 0; i < 1e2; i++) {
+    var length = Math.round(Math.random() * 2e6)
+    var fill = Math.round(Math.random() * 255)
+    var buf = index.Buffer.alloc(length, fill)
+    if (!buffer.Buffer.isBuffer(buf)) ok = false
+    if (buf.length !== length) ok = false
+    for (var j = 0; j < length; j++) {
+      if (buf[j] !== fill) ok = false
+    }
+  }
+  t.ok(ok)
+  t.deepEqual(index.Buffer.alloc(9, 'a'), index.Buffer.alloc(9, 97))
+  t.notDeepEqual(index.Buffer.alloc(9, 'a'), index.Buffer.alloc(9, 98))
+
+  var tmp = new buffer.Buffer(2)
+  tmp.fill('ok')
+  if (tmp[1] === tmp[0]) {
+    // Outdated Node.js
+    t.deepEqual(index.Buffer.alloc(5, 'ok'), index.Buffer.from('ooooo'))
+  } else {
+    t.deepEqual(index.Buffer.alloc(5, 'ok'), index.Buffer.from('okoko'))
+  }
+  t.notDeepEqual(index.Buffer.alloc(5, 'ok'), index.Buffer.from('kokok'))
+
+  t.end()
+})
+
+test('safer.Buffer.from returns results same as Buffer constructor', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.deepEqual(impl.Buffer.from(''), new buffer.Buffer(''))
+    t.deepEqual(impl.Buffer.from('string'), new buffer.Buffer('string'))
+    t.deepEqual(impl.Buffer.from('string', 'utf-8'), new buffer.Buffer('string', 'utf-8'))
+    t.deepEqual(impl.Buffer.from('b25ldHdvdGhyZWU=', 'base64'), new buffer.Buffer('b25ldHdvdGhyZWU=', 'base64'))
+    t.deepEqual(impl.Buffer.from([0, 42, 3]), new buffer.Buffer([0, 42, 3]))
+    t.deepEqual(impl.Buffer.from(new Uint8Array([0, 42, 3])), new buffer.Buffer(new Uint8Array([0, 42, 3])))
+    t.deepEqual(impl.Buffer.from([]), new buffer.Buffer([]))
+  })
+  t.end()
+})
+
+test('safer.Buffer.from returns consistent results', function (t) {
+  [index, safer, dangerous].forEach(function (impl) {
+    t.deepEqual(impl.Buffer.from(''), impl.Buffer.alloc(0))
+    t.deepEqual(impl.Buffer.from([]), impl.Buffer.alloc(0))
+    t.deepEqual(impl.Buffer.from(new Uint8Array([])), impl.Buffer.alloc(0))
+    t.deepEqual(impl.Buffer.from('string', 'utf-8'), impl.Buffer.from('string'))
+    t.deepEqual(impl.Buffer.from('string'), impl.Buffer.from([115, 116, 114, 105, 110, 103]))
+    t.deepEqual(impl.Buffer.from('string'), impl.Buffer.from(impl.Buffer.from('string')))
+    t.deepEqual(impl.Buffer.from('b25ldHdvdGhyZWU=', 'base64'), impl.Buffer.from('onetwothree'))
+    t.notDeepEqual(impl.Buffer.from('b25ldHdvdGhyZWU='), impl.Buffer.from('onetwothree'))
+  })
+  t.end()
+})
diff --git a/server/node_modules/semver/LICENSE b/server/node_modules/semver/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/semver/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/semver/README.md b/server/node_modules/semver/README.md
new file mode 100644
index 0000000..e9d1bc5
--- /dev/null
+++ b/server/node_modules/semver/README.md
@@ -0,0 +1,665 @@
+semver(1) -- The semantic versioner for npm
+===========================================
+
+## Install
+
+```bash
+npm install semver
+````
+
+## Usage
+
+As a node module:
+
+```js
+const semver = require('semver')
+
+semver.valid('1.2.3') // '1.2.3'
+semver.valid('a.b.c') // null
+semver.clean('  =v1.2.3   ') // '1.2.3'
+semver.satisfies('1.2.3', '1.x || >=2.5.0 || 5.0.0 - 7.2.3') // true
+semver.gt('1.2.3', '9.8.7') // false
+semver.lt('1.2.3', '9.8.7') // true
+semver.minVersion('>=1.0.0') // '1.0.0'
+semver.valid(semver.coerce('v2')) // '2.0.0'
+semver.valid(semver.coerce('42.6.7.9.3-alpha')) // '42.6.7'
+```
+
+You can also just load the module for the function that you care about if
+you'd like to minimize your footprint.
+
+```js
+// load the whole API at once in a single object
+const semver = require('semver')
+
+// or just load the bits you need
+// all of them listed here, just pick and choose what you want
+
+// classes
+const SemVer = require('semver/classes/semver')
+const Comparator = require('semver/classes/comparator')
+const Range = require('semver/classes/range')
+
+// functions for working with versions
+const semverParse = require('semver/functions/parse')
+const semverValid = require('semver/functions/valid')
+const semverClean = require('semver/functions/clean')
+const semverInc = require('semver/functions/inc')
+const semverDiff = require('semver/functions/diff')
+const semverMajor = require('semver/functions/major')
+const semverMinor = require('semver/functions/minor')
+const semverPatch = require('semver/functions/patch')
+const semverPrerelease = require('semver/functions/prerelease')
+const semverCompare = require('semver/functions/compare')
+const semverRcompare = require('semver/functions/rcompare')
+const semverCompareLoose = require('semver/functions/compare-loose')
+const semverCompareBuild = require('semver/functions/compare-build')
+const semverSort = require('semver/functions/sort')
+const semverRsort = require('semver/functions/rsort')
+
+// low-level comparators between versions
+const semverGt = require('semver/functions/gt')
+const semverLt = require('semver/functions/lt')
+const semverEq = require('semver/functions/eq')
+const semverNeq = require('semver/functions/neq')
+const semverGte = require('semver/functions/gte')
+const semverLte = require('semver/functions/lte')
+const semverCmp = require('semver/functions/cmp')
+const semverCoerce = require('semver/functions/coerce')
+
+// working with ranges
+const semverSatisfies = require('semver/functions/satisfies')
+const semverMaxSatisfying = require('semver/ranges/max-satisfying')
+const semverMinSatisfying = require('semver/ranges/min-satisfying')
+const semverToComparators = require('semver/ranges/to-comparators')
+const semverMinVersion = require('semver/ranges/min-version')
+const semverValidRange = require('semver/ranges/valid')
+const semverOutside = require('semver/ranges/outside')
+const semverGtr = require('semver/ranges/gtr')
+const semverLtr = require('semver/ranges/ltr')
+const semverIntersects = require('semver/ranges/intersects')
+const semverSimplifyRange = require('semver/ranges/simplify')
+const semverRangeSubset = require('semver/ranges/subset')
+```
+
+As a command-line utility:
+
+```
+$ semver -h
+
+A JavaScript implementation of the https://semver.org/ specification
+Copyright Isaac Z. Schlueter
+
+Usage: semver [options] <version> [<version> [...]]
+Prints valid versions sorted by SemVer precedence
+
+Options:
+-r --range <range>
+        Print versions that match the specified range.
+
+-i --increment [<level>]
+        Increment a version by the specified level.  Level can
+        be one of: major, minor, patch, premajor, preminor,
+        prepatch, prerelease, or release.  Default level is 'patch'.
+        Only one version may be specified.
+
+--preid <identifier>
+        Identifier to be used to prefix premajor, preminor,
+        prepatch or prerelease version increments.
+
+-l --loose
+        Interpret versions and ranges loosely
+
+-n <0|1|false>
+        Base number for prerelease identifier (default: 0).
+        Use false to omit the number altogether.
+
+-p --include-prerelease
+        Always include prerelease versions in range matching
+
+-c --coerce
+        Coerce a string into SemVer if possible
+        (does not imply --loose)
+
+--rtl
+        Coerce version strings right to left
+
+--ltr
+        Coerce version strings left to right (default)
+
+Program exits successfully if any valid version satisfies
+all supplied ranges, and prints all satisfying versions.
+
+If no satisfying versions are found, then exits failure.
+
+Versions are printed in ascending order, so supplying
+multiple versions to the utility will just sort them.
+```
+
+## Versions
+
+A "version" is described by the `v2.0.0` specification found at
+<https://semver.org/>.
+
+A leading `"="` or `"v"` character is stripped off and ignored.
+Support for stripping a leading "v" is kept for compatibility with `v1.0.0` of the SemVer
+specification but should not be used anymore.
+
+## Ranges
+
+A `version range` is a set of `comparators` that specify versions
+that satisfy the range.
+
+A `comparator` is composed of an `operator` and a `version`.  The set
+of primitive `operators` is:
+
+* `<` Less than
+* `<=` Less than or equal to
+* `>` Greater than
+* `>=` Greater than or equal to
+* `=` Equal.  If no operator is specified, then equality is assumed,
+  so this operator is optional but MAY be included.
+
+For example, the comparator `>=1.2.7` would match the versions
+`1.2.7`, `1.2.8`, `2.5.3`, and `1.3.9`, but not the versions `1.2.6`
+or `1.1.0`. The comparator `>1` is equivalent to `>=2.0.0` and
+would match the versions `2.0.0` and `3.1.0`, but not the versions
+`1.0.1` or `1.1.0`.
+
+Comparators can be joined by whitespace to form a `comparator set`,
+which is satisfied by the **intersection** of all of the comparators
+it includes.
+
+A range is composed of one or more comparator sets, joined by `||`.  A
+version matches a range if and only if every comparator in at least
+one of the `||`-separated comparator sets is satisfied by the version.
+
+For example, the range `>=1.2.7 <1.3.0` would match the versions
+`1.2.7`, `1.2.8`, and `1.2.99`, but not the versions `1.2.6`, `1.3.0`,
+or `1.1.0`.
+
+The range `1.2.7 || >=1.2.9 <2.0.0` would match the versions `1.2.7`,
+`1.2.9`, and `1.4.6`, but not the versions `1.2.8` or `2.0.0`.
+
+### Prerelease Tags
+
+If a version has a prerelease tag (for example, `1.2.3-alpha.3`) then
+it will only be allowed to satisfy comparator sets if at least one
+comparator with the same `[major, minor, patch]` tuple also has a
+prerelease tag.
+
+For example, the range `>1.2.3-alpha.3` would be allowed to match the
+version `1.2.3-alpha.7`, but it would *not* be satisfied by
+`3.4.5-alpha.9`, even though `3.4.5-alpha.9` is technically "greater
+than" `1.2.3-alpha.3` according to the SemVer sort rules.  The version
+range only accepts prerelease tags on the `1.2.3` version.
+Version `3.4.5` *would* satisfy the range because it does not have a
+prerelease flag, and `3.4.5` is greater than `1.2.3-alpha.7`.
+
+The purpose of this behavior is twofold.  First, prerelease versions
+frequently are updated very quickly, and contain many breaking changes
+that are (by the author's design) not yet fit for public consumption.
+Therefore, by default, they are excluded from range-matching
+semantics.
+
+Second, a user who has opted into using a prerelease version has
+indicated the intent to use *that specific* set of
+alpha/beta/rc versions.  By including a prerelease tag in the range,
+the user is indicating that they are aware of the risk.  However, it
+is still not appropriate to assume that they have opted into taking a
+similar risk on the *next* set of prerelease versions.
+
+Note that this behavior can be suppressed (treating all prerelease
+versions as if they were normal versions, for range-matching)
+by setting the `includePrerelease` flag on the options
+object to any
+[functions](https://github.com/npm/node-semver#functions) that do
+range matching.
+
+#### Prerelease Identifiers
+
+The method `.inc` takes an additional `identifier` string argument that
+will append the value of the string as a prerelease identifier:
+
+```javascript
+semver.inc('1.2.3', 'prerelease', 'beta')
+// '1.2.4-beta.0'
+```
+
+command-line example:
+
+```bash
+$ semver 1.2.3 -i prerelease --preid beta
+1.2.4-beta.0
+```
+
+Which then can be used to increment further:
+
+```bash
+$ semver 1.2.4-beta.0 -i prerelease
+1.2.4-beta.1
+```
+
+To get out of the prerelease phase, use the `release` option:
+
+```bash
+$ semver 1.2.4-beta.1 -i release
+1.2.4
+```
+
+#### Prerelease Identifier Base
+
+The method `.inc` takes an optional parameter 'identifierBase' string
+that will let you let your prerelease number as zero-based or one-based.
+Set to `false` to omit the prerelease number altogether.
+If you do not specify this parameter, it will default to zero-based.
+
+```javascript
+semver.inc('1.2.3', 'prerelease', 'beta', '1')
+// '1.2.4-beta.1'
+```
+
+```javascript
+semver.inc('1.2.3', 'prerelease', 'beta', false)
+// '1.2.4-beta'
+```
+
+command-line example:
+
+```bash
+$ semver 1.2.3 -i prerelease --preid beta -n 1
+1.2.4-beta.1
+```
+
+```bash
+$ semver 1.2.3 -i prerelease --preid beta -n false
+1.2.4-beta
+```
+
+### Advanced Range Syntax
+
+Advanced range syntax desugars to primitive comparators in
+deterministic ways.
+
+Advanced ranges may be combined in the same way as primitive
+comparators using white space or `||`.
+
+#### Hyphen Ranges `X.Y.Z - A.B.C`
+
+Specifies an inclusive set.
+
+* `1.2.3 - 2.3.4` := `>=1.2.3 <=2.3.4`
+
+If a partial version is provided as the first version in the inclusive
+range, then the missing pieces are replaced with zeroes.
+
+* `1.2 - 2.3.4` := `>=1.2.0 <=2.3.4`
+
+If a partial version is provided as the second version in the
+inclusive range, then all versions that start with the supplied parts
+of the tuple are accepted, but nothing that would be greater than the
+provided tuple parts.
+
+* `1.2.3 - 2.3` := `>=1.2.3 <2.4.0-0`
+* `1.2.3 - 2` := `>=1.2.3 <3.0.0-0`
+
+#### X-Ranges `1.2.x` `1.X` `1.2.*` `*`
+
+Any of `X`, `x`, or `*` may be used to "stand in" for one of the
+numeric values in the `[major, minor, patch]` tuple.
+
+* `*` := `>=0.0.0` (Any non-prerelease version satisfies, unless
+  `includePrerelease` is specified, in which case any version at all
+  satisfies)
+* `1.x` := `>=1.0.0 <2.0.0-0` (Matching major version)
+* `1.2.x` := `>=1.2.0 <1.3.0-0` (Matching major and minor versions)
+
+A partial version range is treated as an X-Range, so the special
+character is in fact optional.
+
+* `""` (empty string) := `*` := `>=0.0.0`
+* `1` := `1.x.x` := `>=1.0.0 <2.0.0-0`
+* `1.2` := `1.2.x` := `>=1.2.0 <1.3.0-0`
+
+#### Tilde Ranges `~1.2.3` `~1.2` `~1`
+
+Allows patch-level changes if a minor version is specified on the
+comparator.  Allows minor-level changes if not.
+
+* `~1.2.3` := `>=1.2.3 <1.(2+1).0` := `>=1.2.3 <1.3.0-0`
+* `~1.2` := `>=1.2.0 <1.(2+1).0` := `>=1.2.0 <1.3.0-0` (Same as `1.2.x`)
+* `~1` := `>=1.0.0 <(1+1).0.0` := `>=1.0.0 <2.0.0-0` (Same as `1.x`)
+* `~0.2.3` := `>=0.2.3 <0.(2+1).0` := `>=0.2.3 <0.3.0-0`
+* `~0.2` := `>=0.2.0 <0.(2+1).0` := `>=0.2.0 <0.3.0-0` (Same as `0.2.x`)
+* `~0` := `>=0.0.0 <(0+1).0.0` := `>=0.0.0 <1.0.0-0` (Same as `0.x`)
+* `~1.2.3-beta.2` := `>=1.2.3-beta.2 <1.3.0-0` Note that prereleases in
+  the `1.2.3` version will be allowed, if they are greater than or
+  equal to `beta.2`.  So, `1.2.3-beta.4` would be allowed, but
+  `1.2.4-beta.2` would not, because it is a prerelease of a
+  different `[major, minor, patch]` tuple.
+
+#### Caret Ranges `^1.2.3` `^0.2.5` `^0.0.4`
+
+Allows changes that do not modify the left-most non-zero element in the
+`[major, minor, patch]` tuple.  In other words, this allows patch and
+minor updates for versions `1.0.0` and above, patch updates for
+versions `0.X >=0.1.0`, and *no* updates for versions `0.0.X`.
+
+Many authors treat a `0.x` version as if the `x` were the major
+"breaking-change" indicator.
+
+Caret ranges are ideal when an author may make breaking changes
+between `0.2.4` and `0.3.0` releases, which is a common practice.
+However, it presumes that there will *not* be breaking changes between
+`0.2.4` and `0.2.5`.  It allows for changes that are presumed to be
+additive (but non-breaking), according to commonly observed practices.
+
+* `^1.2.3` := `>=1.2.3 <2.0.0-0`
+* `^0.2.3` := `>=0.2.3 <0.3.0-0`
+* `^0.0.3` := `>=0.0.3 <0.0.4-0`
+* `^1.2.3-beta.2` := `>=1.2.3-beta.2 <2.0.0-0` Note that prereleases in
+  the `1.2.3` version will be allowed, if they are greater than or
+  equal to `beta.2`.  So, `1.2.3-beta.4` would be allowed, but
+  `1.2.4-beta.2` would not, because it is a prerelease of a
+  different `[major, minor, patch]` tuple.
+* `^0.0.3-beta` := `>=0.0.3-beta <0.0.4-0`  Note that prereleases in the
+  `0.0.3` version *only* will be allowed, if they are greater than or
+  equal to `beta`.  So, `0.0.3-pr.2` would be allowed.
+
+When parsing caret ranges, a missing `patch` value desugars to the
+number `0`, but will allow flexibility within that value, even if the
+major and minor versions are both `0`.
+
+* `^1.2.x` := `>=1.2.0 <2.0.0-0`
+* `^0.0.x` := `>=0.0.0 <0.1.0-0`
+* `^0.0` := `>=0.0.0 <0.1.0-0`
+
+A missing `minor` and `patch` values will desugar to zero, but also
+allow flexibility within those values, even if the major version is
+zero.
+
+* `^1.x` := `>=1.0.0 <2.0.0-0`
+* `^0.x` := `>=0.0.0 <1.0.0-0`
+
+### Range Grammar
+
+Putting all this together, here is a Backus-Naur grammar for ranges,
+for the benefit of parser authors:
+
+```bnf
+range-set  ::= range ( logical-or range ) *
+logical-or ::= ( ' ' ) * '||' ( ' ' ) *
+range      ::= hyphen | simple ( ' ' simple ) * | ''
+hyphen     ::= partial ' - ' partial
+simple     ::= primitive | partial | tilde | caret
+primitive  ::= ( '<' | '>' | '>=' | '<=' | '=' ) partial
+partial    ::= xr ( '.' xr ( '.' xr qualifier ? )? )?
+xr         ::= 'x' | 'X' | '*' | nr
+nr         ::= '0' | ['1'-'9'] ( ['0'-'9'] ) *
+tilde      ::= '~' partial
+caret      ::= '^' partial
+qualifier  ::= ( '-' pre )? ( '+' build )?
+pre        ::= parts
+build      ::= parts
+parts      ::= part ( '.' part ) *
+part       ::= nr | [-0-9A-Za-z]+
+```
+
+## Functions
+
+All methods and classes take a final `options` object argument.  All
+options in this object are `false` by default.  The options supported
+are:
+
+- `loose`: Be more forgiving about not-quite-valid semver strings.
+  (Any resulting output will always be 100% strict compliant, of
+  course.)  For backwards compatibility reasons, if the `options`
+  argument is a boolean value instead of an object, it is interpreted
+  to be the `loose` param.
+- `includePrerelease`: Set to suppress the [default
+  behavior](https://github.com/npm/node-semver#prerelease-tags) of
+  excluding prerelease tagged versions from ranges unless they are
+  explicitly opted into.
+
+Strict-mode Comparators and Ranges will be strict about the SemVer
+strings that they parse.
+
+* `valid(v)`: Return the parsed version, or null if it's not valid.
+* `inc(v, releaseType, options, identifier, identifierBase)`: 
+  Return the version incremented by the release
+  type (`major`, `premajor`, `minor`, `preminor`, `patch`,
+  `prepatch`, `prerelease`, or `release`), or null if it's not valid
+  * `premajor` in one call will bump the version up to the next major
+    version and down to a prerelease of that major version.
+    `preminor`, and `prepatch` work the same way.
+  * If called from a non-prerelease version, `prerelease` will work the
+    same as `prepatch`. It increments the patch version and then makes a
+    prerelease. If the input version is already a prerelease it simply
+    increments it.
+  * `release` will remove any prerelease part of the version.
+  * `identifier` can be used to prefix `premajor`, `preminor`,
+    `prepatch`, or `prerelease` version increments. `identifierBase`
+    is the base to be used for the `prerelease` identifier.
+* `prerelease(v)`: Returns an array of prerelease components, or null
+  if none exist. Example: `prerelease('1.2.3-alpha.1') -> ['alpha', 1]`
+* `major(v)`: Return the major version number.
+* `minor(v)`: Return the minor version number.
+* `patch(v)`: Return the patch version number.
+* `intersects(r1, r2, loose)`: Return true if the two supplied ranges
+  or comparators intersect.
+* `parse(v)`: Attempt to parse a string as a semantic version, returning either
+  a `SemVer` object or `null`.
+
+### Comparison
+
+* `gt(v1, v2)`: `v1 > v2`
+* `gte(v1, v2)`: `v1 >= v2`
+* `lt(v1, v2)`: `v1 < v2`
+* `lte(v1, v2)`: `v1 <= v2`
+* `eq(v1, v2)`: `v1 == v2` This is true if they're logically equivalent,
+  even if they're not the same string.  You already know how to
+  compare strings.
+* `neq(v1, v2)`: `v1 != v2` The opposite of `eq`.
+* `cmp(v1, comparator, v2)`: Pass in a comparison string, and it'll call
+  the corresponding function above.  `"==="` and `"!=="` do simple
+  string comparison, but are included for completeness.  Throws if an
+  invalid comparison string is provided.
+* `compare(v1, v2)`: Return `0` if `v1 == v2`, or `1` if `v1` is greater, or `-1` if
+  `v2` is greater.  Sorts in ascending order if passed to `Array.sort()`.
+* `rcompare(v1, v2)`: The reverse of `compare`.  Sorts an array of versions
+  in descending order when passed to `Array.sort()`.
+* `compareBuild(v1, v2)`: The same as `compare` but considers `build` when two versions
+  are equal.  Sorts in ascending order if passed to `Array.sort()`.
+* `compareLoose(v1, v2)`: Short for `compare(v1, v2, { loose: true })`.
+* `diff(v1, v2)`: Returns the difference between two versions by the release type
+  (`major`, `premajor`, `minor`, `preminor`, `patch`, `prepatch`, or `prerelease`),
+  or null if the versions are the same.
+
+### Sorting
+
+* `sort(versions)`: Returns a sorted array of versions based on the `compareBuild` 
+  function.
+* `rsort(versions)`: The reverse of `sort`. Returns an array of versions based on
+  the `compareBuild` function in descending order.
+
+### Comparators
+
+* `intersects(comparator)`: Return true if the comparators intersect
+
+### Ranges
+
+* `validRange(range)`: Return the valid range or null if it's not valid.
+* `satisfies(version, range)`: Return true if the version satisfies the
+  range.
+* `maxSatisfying(versions, range)`: Return the highest version in the list
+  that satisfies the range, or `null` if none of them do.
+* `minSatisfying(versions, range)`: Return the lowest version in the list
+  that satisfies the range, or `null` if none of them do.
+* `minVersion(range)`: Return the lowest version that can match
+  the given range.
+* `gtr(version, range)`: Return `true` if the version is greater than all the
+  versions possible in the range.
+* `ltr(version, range)`: Return `true` if the version is less than all the
+  versions possible in the range.
+* `outside(version, range, hilo)`: Return true if the version is outside
+  the bounds of the range in either the high or low direction.  The
+  `hilo` argument must be either the string `'>'` or `'<'`.  (This is
+  the function called by `gtr` and `ltr`.)
+* `intersects(range)`: Return true if any of the range comparators intersect.
+* `simplifyRange(versions, range)`: Return a "simplified" range that
+  matches the same items in the `versions` list as the range specified.  Note
+  that it does *not* guarantee that it would match the same versions in all
+  cases, only for the set of versions provided.  This is useful when
+  generating ranges by joining together multiple versions with `||`
+  programmatically, to provide the user with something a bit more
+  ergonomic.  If the provided range is shorter in string-length than the
+  generated range, then that is returned.
+* `subset(subRange, superRange)`: Return `true` if the `subRange` range is
+  entirely contained by the `superRange` range.
+
+Note that, since ranges may be non-contiguous, a version might not be
+greater than a range, less than a range, *or* satisfy a range!  For
+example, the range `1.2 <1.2.9 || >2.0.0` would have a hole from `1.2.9`
+until `2.0.0`, so version `1.2.10` would not be greater than the
+range (because `2.0.1` satisfies, which is higher), nor less than the
+range (since `1.2.8` satisfies, which is lower), and it also does not
+satisfy the range.
+
+If you want to know if a version satisfies or does not satisfy a
+range, use the `satisfies(version, range)` function.
+
+### Coercion
+
+* `coerce(version, options)`: Coerces a string to semver if possible
+
+This aims to provide a very forgiving translation of a non-semver string to
+semver. It looks for the first digit in a string and consumes all
+remaining characters which satisfy at least a partial semver (e.g., `1`,
+`1.2`, `1.2.3`) up to the max permitted length (256 characters).  Longer
+versions are simply truncated (`4.6.3.9.2-alpha2` becomes `4.6.3`).  All
+surrounding text is simply ignored (`v3.4 replaces v3.3.1` becomes
+`3.4.0`).  Only text which lacks digits will fail coercion (`version one`
+is not valid).  The maximum length for any semver component considered for
+coercion is 16 characters; longer components will be ignored
+(`10000000000000000.4.7.4` becomes `4.7.4`).  The maximum value for any
+semver component is `Number.MAX_SAFE_INTEGER || (2**53 - 1)`; higher value
+components are invalid (`9999999999999999.4.7.4` is likely invalid).
+
+If the `options.rtl` flag is set, then `coerce` will return the right-most
+coercible tuple that does not share an ending index with a longer coercible
+tuple.  For example, `1.2.3.4` will return `2.3.4` in rtl mode, not
+`4.0.0`.  `1.2.3/4` will return `4.0.0`, because the `4` is not a part of
+any other overlapping SemVer tuple.
+
+If the `options.includePrerelease` flag is set, then the `coerce` result will contain
+prerelease and build parts of a version.  For example, `1.2.3.4-rc.1+rev.2`
+will preserve prerelease `rc.1` and build `rev.2` in the result.
+
+### Clean
+
+* `clean(version)`: Clean a string to be a valid semver if possible
+
+This will return a cleaned and trimmed semver version. If the provided
+version is not valid a null will be returned. This does not work for
+ranges.
+
+ex.
+* `s.clean(' = v 2.1.5foo')`: `null`
+* `s.clean(' = v 2.1.5foo', { loose: true })`: `'2.1.5-foo'`
+* `s.clean(' = v 2.1.5-foo')`: `null`
+* `s.clean(' = v 2.1.5-foo', { loose: true })`: `'2.1.5-foo'`
+* `s.clean('=v2.1.5')`: `'2.1.5'`
+* `s.clean('  =v2.1.5')`: `'2.1.5'`
+* `s.clean('      2.1.5   ')`: `'2.1.5'`
+* `s.clean('~1.0.0')`: `null`
+
+## Constants
+
+As a convenience, helper constants are exported to provide information about what `node-semver` supports:
+
+### `RELEASE_TYPES`
+
+- major
+- premajor
+- minor
+- preminor
+- patch
+- prepatch
+- prerelease
+
+```
+const semver = require('semver');
+
+if (semver.RELEASE_TYPES.includes(arbitraryUserInput)) {
+  console.log('This is a valid release type!');
+} else {
+  console.warn('This is NOT a valid release type!');
+}
+```
+
+### `SEMVER_SPEC_VERSION`
+
+2.0.0
+
+```
+const semver = require('semver');
+
+console.log('We are currently using the semver specification version:', semver.SEMVER_SPEC_VERSION);
+```
+
+## Exported Modules
+
+
+
+You may pull in just the part of this semver utility that you need if you
+are sensitive to packing and tree-shaking concerns.  The main
+`require('semver')` export uses getter functions to lazily load the parts
+of the API that are used.
+
+The following modules are available:
+
+* `require('semver')`
+* `require('semver/classes')`
+* `require('semver/classes/comparator')`
+* `require('semver/classes/range')`
+* `require('semver/classes/semver')`
+* `require('semver/functions/clean')`
+* `require('semver/functions/cmp')`
+* `require('semver/functions/coerce')`
+* `require('semver/functions/compare')`
+* `require('semver/functions/compare-build')`
+* `require('semver/functions/compare-loose')`
+* `require('semver/functions/diff')`
+* `require('semver/functions/eq')`
+* `require('semver/functions/gt')`
+* `require('semver/functions/gte')`
+* `require('semver/functions/inc')`
+* `require('semver/functions/lt')`
+* `require('semver/functions/lte')`
+* `require('semver/functions/major')`
+* `require('semver/functions/minor')`
+* `require('semver/functions/neq')`
+* `require('semver/functions/parse')`
+* `require('semver/functions/patch')`
+* `require('semver/functions/prerelease')`
+* `require('semver/functions/rcompare')`
+* `require('semver/functions/rsort')`
+* `require('semver/functions/satisfies')`
+* `require('semver/functions/sort')`
+* `require('semver/functions/valid')`
+* `require('semver/ranges/gtr')`
+* `require('semver/ranges/intersects')`
+* `require('semver/ranges/ltr')`
+* `require('semver/ranges/max-satisfying')`
+* `require('semver/ranges/min-satisfying')`
+* `require('semver/ranges/min-version')`
+* `require('semver/ranges/outside')`
+* `require('semver/ranges/simplify')`
+* `require('semver/ranges/subset')`
+* `require('semver/ranges/to-comparators')`
+* `require('semver/ranges/valid')`
+
diff --git a/server/node_modules/semver/bin/semver.js b/server/node_modules/semver/bin/semver.js
new file mode 100755
index 0000000..d62bfc0
--- /dev/null
+++ b/server/node_modules/semver/bin/semver.js
@@ -0,0 +1,191 @@
+#!/usr/bin/env node
+// Standalone semver comparison program.
+// Exits successfully and prints matching version(s) if
+// any supplied version is valid and passes all tests.
+
+'use strict'
+
+const argv = process.argv.slice(2)
+
+let versions = []
+
+const range = []
+
+let inc = null
+
+const version = require('../package.json').version
+
+let loose = false
+
+let includePrerelease = false
+
+let coerce = false
+
+let rtl = false
+
+let identifier
+
+let identifierBase
+
+const semver = require('../')
+const parseOptions = require('../internal/parse-options')
+
+let reverse = false
+
+let options = {}
+
+const main = () => {
+  if (!argv.length) {
+    return help()
+  }
+  while (argv.length) {
+    let a = argv.shift()
+    const indexOfEqualSign = a.indexOf('=')
+    if (indexOfEqualSign !== -1) {
+      const value = a.slice(indexOfEqualSign + 1)
+      a = a.slice(0, indexOfEqualSign)
+      argv.unshift(value)
+    }
+    switch (a) {
+      case '-rv': case '-rev': case '--rev': case '--reverse':
+        reverse = true
+        break
+      case '-l': case '--loose':
+        loose = true
+        break
+      case '-p': case '--include-prerelease':
+        includePrerelease = true
+        break
+      case '-v': case '--version':
+        versions.push(argv.shift())
+        break
+      case '-i': case '--inc': case '--increment':
+        switch (argv[0]) {
+          case 'major': case 'minor': case 'patch': case 'prerelease':
+          case 'premajor': case 'preminor': case 'prepatch':
+          case 'release':
+            inc = argv.shift()
+            break
+          default:
+            inc = 'patch'
+            break
+        }
+        break
+      case '--preid':
+        identifier = argv.shift()
+        break
+      case '-r': case '--range':
+        range.push(argv.shift())
+        break
+      case '-n':
+        identifierBase = argv.shift()
+        if (identifierBase === 'false') {
+          identifierBase = false
+        }
+        break
+      case '-c': case '--coerce':
+        coerce = true
+        break
+      case '--rtl':
+        rtl = true
+        break
+      case '--ltr':
+        rtl = false
+        break
+      case '-h': case '--help': case '-?':
+        return help()
+      default:
+        versions.push(a)
+        break
+    }
+  }
+
+  options = parseOptions({ loose, includePrerelease, rtl })
+
+  versions = versions.map((v) => {
+    return coerce ? (semver.coerce(v, options) || { version: v }).version : v
+  }).filter((v) => {
+    return semver.valid(v, options)
+  })
+  if (!versions.length) {
+    return fail()
+  }
+  if (inc && (versions.length !== 1 || range.length)) {
+    return failInc()
+  }
+
+  for (let i = 0, l = range.length; i < l; i++) {
+    versions = versions.filter((v) => {
+      return semver.satisfies(v, range[i], options)
+    })
+    if (!versions.length) {
+      return fail()
+    }
+  }
+  versions
+    .sort((a, b) => semver[reverse ? 'rcompare' : 'compare'](a, b, options))
+    .map(v => semver.clean(v, options))
+    .map(v => inc ? semver.inc(v, inc, options, identifier, identifierBase) : v)
+    .forEach(v => console.log(v))
+}
+
+const failInc = () => {
+  console.error('--inc can only be used on a single version with no range')
+  fail()
+}
+
+const fail = () => process.exit(1)
+
+const help = () => console.log(
+`SemVer ${version}
+
+A JavaScript implementation of the https://semver.org/ specification
+Copyright Isaac Z. Schlueter
+
+Usage: semver [options] <version> [<version> [...]]
+Prints valid versions sorted by SemVer precedence
+
+Options:
+-r --range <range>
+        Print versions that match the specified range.
+
+-i --increment [<level>]
+        Increment a version by the specified level.  Level can
+        be one of: major, minor, patch, premajor, preminor,
+        prepatch, prerelease, or release.  Default level is 'patch'.
+        Only one version may be specified.
+
+--preid <identifier>
+        Identifier to be used to prefix premajor, preminor,
+        prepatch or prerelease version increments.
+
+-l --loose
+        Interpret versions and ranges loosely
+
+-p --include-prerelease
+        Always include prerelease versions in range matching
+
+-c --coerce
+        Coerce a string into SemVer if possible
+        (does not imply --loose)
+
+--rtl
+        Coerce version strings right to left
+
+--ltr
+        Coerce version strings left to right (default)
+
+-n <base>
+        Base number to be used for the prerelease identifier.
+        Can be either 0 or 1, or false to omit the number altogether.
+        Defaults to 0.
+
+Program exits successfully if any valid version satisfies
+all supplied ranges, and prints all satisfying versions.
+
+If no satisfying versions are found, then exits failure.
+
+Versions are printed in ascending order, so supplying
+multiple versions to the utility will just sort them.`)
+
+main()
diff --git a/server/node_modules/semver/classes/comparator.js b/server/node_modules/semver/classes/comparator.js
new file mode 100644
index 0000000..647c1f0
--- /dev/null
+++ b/server/node_modules/semver/classes/comparator.js
@@ -0,0 +1,143 @@
+'use strict'
+
+const ANY = Symbol('SemVer ANY')
+// hoisted class for cyclic dependency
+class Comparator {
+  static get ANY () {
+    return ANY
+  }
+
+  constructor (comp, options) {
+    options = parseOptions(options)
+
+    if (comp instanceof Comparator) {
+      if (comp.loose === !!options.loose) {
+        return comp
+      } else {
+        comp = comp.value
+      }
+    }
+
+    comp = comp.trim().split(/\s+/).join(' ')
+    debug('comparator', comp, options)
+    this.options = options
+    this.loose = !!options.loose
+    this.parse(comp)
+
+    if (this.semver === ANY) {
+      this.value = ''
+    } else {
+      this.value = this.operator + this.semver.version
+    }
+
+    debug('comp', this)
+  }
+
+  parse (comp) {
+    const r = this.options.loose ? re[t.COMPARATORLOOSE] : re[t.COMPARATOR]
+    const m = comp.match(r)
+
+    if (!m) {
+      throw new TypeError(`Invalid comparator: ${comp}`)
+    }
+
+    this.operator = m[1] !== undefined ? m[1] : ''
+    if (this.operator === '=') {
+      this.operator = ''
+    }
+
+    // if it literally is just '>' or '' then allow anything.
+    if (!m[2]) {
+      this.semver = ANY
+    } else {
+      this.semver = new SemVer(m[2], this.options.loose)
+    }
+  }
+
+  toString () {
+    return this.value
+  }
+
+  test (version) {
+    debug('Comparator.test', version, this.options.loose)
+
+    if (this.semver === ANY || version === ANY) {
+      return true
+    }
+
+    if (typeof version === 'string') {
+      try {
+        version = new SemVer(version, this.options)
+      } catch (er) {
+        return false
+      }
+    }
+
+    return cmp(version, this.operator, this.semver, this.options)
+  }
+
+  intersects (comp, options) {
+    if (!(comp instanceof Comparator)) {
+      throw new TypeError('a Comparator is required')
+    }
+
+    if (this.operator === '') {
+      if (this.value === '') {
+        return true
+      }
+      return new Range(comp.value, options).test(this.value)
+    } else if (comp.operator === '') {
+      if (comp.value === '') {
+        return true
+      }
+      return new Range(this.value, options).test(comp.semver)
+    }
+
+    options = parseOptions(options)
+
+    // Special cases where nothing can possibly be lower
+    if (options.includePrerelease &&
+      (this.value === '<0.0.0-0' || comp.value === '<0.0.0-0')) {
+      return false
+    }
+    if (!options.includePrerelease &&
+      (this.value.startsWith('<0.0.0') || comp.value.startsWith('<0.0.0'))) {
+      return false
+    }
+
+    // Same direction increasing (> or >=)
+    if (this.operator.startsWith('>') && comp.operator.startsWith('>')) {
+      return true
+    }
+    // Same direction decreasing (< or <=)
+    if (this.operator.startsWith('<') && comp.operator.startsWith('<')) {
+      return true
+    }
+    // same SemVer and both sides are inclusive (<= or >=)
+    if (
+      (this.semver.version === comp.semver.version) &&
+      this.operator.includes('=') && comp.operator.includes('=')) {
+      return true
+    }
+    // opposite directions less than
+    if (cmp(this.semver, '<', comp.semver, options) &&
+      this.operator.startsWith('>') && comp.operator.startsWith('<')) {
+      return true
+    }
+    // opposite directions greater than
+    if (cmp(this.semver, '>', comp.semver, options) &&
+      this.operator.startsWith('<') && comp.operator.startsWith('>')) {
+      return true
+    }
+    return false
+  }
+}
+
+module.exports = Comparator
+
+const parseOptions = require('../internal/parse-options')
+const { safeRe: re, t } = require('../internal/re')
+const cmp = require('../functions/cmp')
+const debug = require('../internal/debug')
+const SemVer = require('./semver')
+const Range = require('./range')
diff --git a/server/node_modules/semver/classes/index.js b/server/node_modules/semver/classes/index.js
new file mode 100644
index 0000000..91c24ec
--- /dev/null
+++ b/server/node_modules/semver/classes/index.js
@@ -0,0 +1,7 @@
+'use strict'
+
+module.exports = {
+  SemVer: require('./semver.js'),
+  Range: require('./range.js'),
+  Comparator: require('./comparator.js'),
+}
diff --git a/server/node_modules/semver/classes/range.js b/server/node_modules/semver/classes/range.js
new file mode 100644
index 0000000..94629ce
--- /dev/null
+++ b/server/node_modules/semver/classes/range.js
@@ -0,0 +1,557 @@
+'use strict'
+
+const SPACE_CHARACTERS = /\s+/g
+
+// hoisted class for cyclic dependency
+class Range {
+  constructor (range, options) {
+    options = parseOptions(options)
+
+    if (range instanceof Range) {
+      if (
+        range.loose === !!options.loose &&
+        range.includePrerelease === !!options.includePrerelease
+      ) {
+        return range
+      } else {
+        return new Range(range.raw, options)
+      }
+    }
+
+    if (range instanceof Comparator) {
+      // just put it in the set and return
+      this.raw = range.value
+      this.set = [[range]]
+      this.formatted = undefined
+      return this
+    }
+
+    this.options = options
+    this.loose = !!options.loose
+    this.includePrerelease = !!options.includePrerelease
+
+    // First reduce all whitespace as much as possible so we do not have to rely
+    // on potentially slow regexes like \s*. This is then stored and used for
+    // future error messages as well.
+    this.raw = range.trim().replace(SPACE_CHARACTERS, ' ')
+
+    // First, split on ||
+    this.set = this.raw
+      .split('||')
+      // map the range to a 2d array of comparators
+      .map(r => this.parseRange(r.trim()))
+      // throw out any comparator lists that are empty
+      // this generally means that it was not a valid range, which is allowed
+      // in loose mode, but will still throw if the WHOLE range is invalid.
+      .filter(c => c.length)
+
+    if (!this.set.length) {
+      throw new TypeError(`Invalid SemVer Range: ${this.raw}`)
+    }
+
+    // if we have any that are not the null set, throw out null sets.
+    if (this.set.length > 1) {
+      // keep the first one, in case they're all null sets
+      const first = this.set[0]
+      this.set = this.set.filter(c => !isNullSet(c[0]))
+      if (this.set.length === 0) {
+        this.set = [first]
+      } else if (this.set.length > 1) {
+        // if we have any that are *, then the range is just *
+        for (const c of this.set) {
+          if (c.length === 1 && isAny(c[0])) {
+            this.set = [c]
+            break
+          }
+        }
+      }
+    }
+
+    this.formatted = undefined
+  }
+
+  get range () {
+    if (this.formatted === undefined) {
+      this.formatted = ''
+      for (let i = 0; i < this.set.length; i++) {
+        if (i > 0) {
+          this.formatted += '||'
+        }
+        const comps = this.set[i]
+        for (let k = 0; k < comps.length; k++) {
+          if (k > 0) {
+            this.formatted += ' '
+          }
+          this.formatted += comps[k].toString().trim()
+        }
+      }
+    }
+    return this.formatted
+  }
+
+  format () {
+    return this.range
+  }
+
+  toString () {
+    return this.range
+  }
+
+  parseRange (range) {
+    // memoize range parsing for performance.
+    // this is a very hot path, and fully deterministic.
+    const memoOpts =
+      (this.options.includePrerelease && FLAG_INCLUDE_PRERELEASE) |
+      (this.options.loose && FLAG_LOOSE)
+    const memoKey = memoOpts + ':' + range
+    const cached = cache.get(memoKey)
+    if (cached) {
+      return cached
+    }
+
+    const loose = this.options.loose
+    // `1.2.3 - 1.2.4` => `>=1.2.3 <=1.2.4`
+    const hr = loose ? re[t.HYPHENRANGELOOSE] : re[t.HYPHENRANGE]
+    range = range.replace(hr, hyphenReplace(this.options.includePrerelease))
+    debug('hyphen replace', range)
+
+    // `> 1.2.3 < 1.2.5` => `>1.2.3 <1.2.5`
+    range = range.replace(re[t.COMPARATORTRIM], comparatorTrimReplace)
+    debug('comparator trim', range)
+
+    // `~ 1.2.3` => `~1.2.3`
+    range = range.replace(re[t.TILDETRIM], tildeTrimReplace)
+    debug('tilde trim', range)
+
+    // `^ 1.2.3` => `^1.2.3`
+    range = range.replace(re[t.CARETTRIM], caretTrimReplace)
+    debug('caret trim', range)
+
+    // At this point, the range is completely trimmed and
+    // ready to be split into comparators.
+
+    let rangeList = range
+      .split(' ')
+      .map(comp => parseComparator(comp, this.options))
+      .join(' ')
+      .split(/\s+/)
+      // >=0.0.0 is equivalent to *
+      .map(comp => replaceGTE0(comp, this.options))
+
+    if (loose) {
+      // in loose mode, throw out any that are not valid comparators
+      rangeList = rangeList.filter(comp => {
+        debug('loose invalid filter', comp, this.options)
+        return !!comp.match(re[t.COMPARATORLOOSE])
+      })
+    }
+    debug('range list', rangeList)
+
+    // if any comparators are the null set, then replace with JUST null set
+    // if more than one comparator, remove any * comparators
+    // also, don't include the same comparator more than once
+    const rangeMap = new Map()
+    const comparators = rangeList.map(comp => new Comparator(comp, this.options))
+    for (const comp of comparators) {
+      if (isNullSet(comp)) {
+        return [comp]
+      }
+      rangeMap.set(comp.value, comp)
+    }
+    if (rangeMap.size > 1 && rangeMap.has('')) {
+      rangeMap.delete('')
+    }
+
+    const result = [...rangeMap.values()]
+    cache.set(memoKey, result)
+    return result
+  }
+
+  intersects (range, options) {
+    if (!(range instanceof Range)) {
+      throw new TypeError('a Range is required')
+    }
+
+    return this.set.some((thisComparators) => {
+      return (
+        isSatisfiable(thisComparators, options) &&
+        range.set.some((rangeComparators) => {
+          return (
+            isSatisfiable(rangeComparators, options) &&
+            thisComparators.every((thisComparator) => {
+              return rangeComparators.every((rangeComparator) => {
+                return thisComparator.intersects(rangeComparator, options)
+              })
+            })
+          )
+        })
+      )
+    })
+  }
+
+  // if ANY of the sets match ALL of its comparators, then pass
+  test (version) {
+    if (!version) {
+      return false
+    }
+
+    if (typeof version === 'string') {
+      try {
+        version = new SemVer(version, this.options)
+      } catch (er) {
+        return false
+      }
+    }
+
+    for (let i = 0; i < this.set.length; i++) {
+      if (testSet(this.set[i], version, this.options)) {
+        return true
+      }
+    }
+    return false
+  }
+}
+
+module.exports = Range
+
+const LRU = require('../internal/lrucache')
+const cache = new LRU()
+
+const parseOptions = require('../internal/parse-options')
+const Comparator = require('./comparator')
+const debug = require('../internal/debug')
+const SemVer = require('./semver')
+const {
+  safeRe: re,
+  t,
+  comparatorTrimReplace,
+  tildeTrimReplace,
+  caretTrimReplace,
+} = require('../internal/re')
+const { FLAG_INCLUDE_PRERELEASE, FLAG_LOOSE } = require('../internal/constants')
+
+const isNullSet = c => c.value === '<0.0.0-0'
+const isAny = c => c.value === ''
+
+// take a set of comparators and determine whether there
+// exists a version which can satisfy it
+const isSatisfiable = (comparators, options) => {
+  let result = true
+  const remainingComparators = comparators.slice()
+  let testComparator = remainingComparators.pop()
+
+  while (result && remainingComparators.length) {
+    result = remainingComparators.every((otherComparator) => {
+      return testComparator.intersects(otherComparator, options)
+    })
+
+    testComparator = remainingComparators.pop()
+  }
+
+  return result
+}
+
+// comprised of xranges, tildes, stars, and gtlt's at this point.
+// already replaced the hyphen ranges
+// turn into a set of JUST comparators.
+const parseComparator = (comp, options) => {
+  comp = comp.replace(re[t.BUILD], '')
+  debug('comp', comp, options)
+  comp = replaceCarets(comp, options)
+  debug('caret', comp)
+  comp = replaceTildes(comp, options)
+  debug('tildes', comp)
+  comp = replaceXRanges(comp, options)
+  debug('xrange', comp)
+  comp = replaceStars(comp, options)
+  debug('stars', comp)
+  return comp
+}
+
+const isX = id => !id || id.toLowerCase() === 'x' || id === '*'
+
+// ~, ~> --> * (any, kinda silly)
+// ~2, ~2.x, ~2.x.x, ~>2, ~>2.x ~>2.x.x --> >=2.0.0 <3.0.0-0
+// ~2.0, ~2.0.x, ~>2.0, ~>2.0.x --> >=2.0.0 <2.1.0-0
+// ~1.2, ~1.2.x, ~>1.2, ~>1.2.x --> >=1.2.0 <1.3.0-0
+// ~1.2.3, ~>1.2.3 --> >=1.2.3 <1.3.0-0
+// ~1.2.0, ~>1.2.0 --> >=1.2.0 <1.3.0-0
+// ~0.0.1 --> >=0.0.1 <0.1.0-0
+const replaceTildes = (comp, options) => {
+  return comp
+    .trim()
+    .split(/\s+/)
+    .map((c) => replaceTilde(c, options))
+    .join(' ')
+}
+
+const replaceTilde = (comp, options) => {
+  const r = options.loose ? re[t.TILDELOOSE] : re[t.TILDE]
+  return comp.replace(r, (_, M, m, p, pr) => {
+    debug('tilde', comp, _, M, m, p, pr)
+    let ret
+
+    if (isX(M)) {
+      ret = ''
+    } else if (isX(m)) {
+      ret = `>=${M}.0.0 <${+M + 1}.0.0-0`
+    } else if (isX(p)) {
+      // ~1.2 == >=1.2.0 <1.3.0-0
+      ret = `>=${M}.${m}.0 <${M}.${+m + 1}.0-0`
+    } else if (pr) {
+      debug('replaceTilde pr', pr)
+      ret = `>=${M}.${m}.${p}-${pr
+      } <${M}.${+m + 1}.0-0`
+    } else {
+      // ~1.2.3 == >=1.2.3 <1.3.0-0
+      ret = `>=${M}.${m}.${p
+      } <${M}.${+m + 1}.0-0`
+    }
+
+    debug('tilde return', ret)
+    return ret
+  })
+}
+
+// ^ --> * (any, kinda silly)
+// ^2, ^2.x, ^2.x.x --> >=2.0.0 <3.0.0-0
+// ^2.0, ^2.0.x --> >=2.0.0 <3.0.0-0
+// ^1.2, ^1.2.x --> >=1.2.0 <2.0.0-0
+// ^1.2.3 --> >=1.2.3 <2.0.0-0
+// ^1.2.0 --> >=1.2.0 <2.0.0-0
+// ^0.0.1 --> >=0.0.1 <0.0.2-0
+// ^0.1.0 --> >=0.1.0 <0.2.0-0
+const replaceCarets = (comp, options) => {
+  return comp
+    .trim()
+    .split(/\s+/)
+    .map((c) => replaceCaret(c, options))
+    .join(' ')
+}
+
+const replaceCaret = (comp, options) => {
+  debug('caret', comp, options)
+  const r = options.loose ? re[t.CARETLOOSE] : re[t.CARET]
+  const z = options.includePrerelease ? '-0' : ''
+  return comp.replace(r, (_, M, m, p, pr) => {
+    debug('caret', comp, _, M, m, p, pr)
+    let ret
+
+    if (isX(M)) {
+      ret = ''
+    } else if (isX(m)) {
+      ret = `>=${M}.0.0${z} <${+M + 1}.0.0-0`
+    } else if (isX(p)) {
+      if (M === '0') {
+        ret = `>=${M}.${m}.0${z} <${M}.${+m + 1}.0-0`
+      } else {
+        ret = `>=${M}.${m}.0${z} <${+M + 1}.0.0-0`
+      }
+    } else if (pr) {
+      debug('replaceCaret pr', pr)
+      if (M === '0') {
+        if (m === '0') {
+          ret = `>=${M}.${m}.${p}-${pr
+          } <${M}.${m}.${+p + 1}-0`
+        } else {
+          ret = `>=${M}.${m}.${p}-${pr
+          } <${M}.${+m + 1}.0-0`
+        }
+      } else {
+        ret = `>=${M}.${m}.${p}-${pr
+        } <${+M + 1}.0.0-0`
+      }
+    } else {
+      debug('no pr')
+      if (M === '0') {
+        if (m === '0') {
+          ret = `>=${M}.${m}.${p
+          }${z} <${M}.${m}.${+p + 1}-0`
+        } else {
+          ret = `>=${M}.${m}.${p
+          }${z} <${M}.${+m + 1}.0-0`
+        }
+      } else {
+        ret = `>=${M}.${m}.${p
+        } <${+M + 1}.0.0-0`
+      }
+    }
+
+    debug('caret return', ret)
+    return ret
+  })
+}
+
+const replaceXRanges = (comp, options) => {
+  debug('replaceXRanges', comp, options)
+  return comp
+    .split(/\s+/)
+    .map((c) => replaceXRange(c, options))
+    .join(' ')
+}
+
+const replaceXRange = (comp, options) => {
+  comp = comp.trim()
+  const r = options.loose ? re[t.XRANGELOOSE] : re[t.XRANGE]
+  return comp.replace(r, (ret, gtlt, M, m, p, pr) => {
+    debug('xRange', comp, ret, gtlt, M, m, p, pr)
+    const xM = isX(M)
+    const xm = xM || isX(m)
+    const xp = xm || isX(p)
+    const anyX = xp
+
+    if (gtlt === '=' && anyX) {
+      gtlt = ''
+    }
+
+    // if we're including prereleases in the match, then we need
+    // to fix this to -0, the lowest possible prerelease value
+    pr = options.includePrerelease ? '-0' : ''
+
+    if (xM) {
+      if (gtlt === '>' || gtlt === '<') {
+        // nothing is allowed
+        ret = '<0.0.0-0'
+      } else {
+        // nothing is forbidden
+        ret = '*'
+      }
+    } else if (gtlt && anyX) {
+      // we know patch is an x, because we have any x at all.
+      // replace X with 0
+      if (xm) {
+        m = 0
+      }
+      p = 0
+
+      if (gtlt === '>') {
+        // >1 => >=2.0.0
+        // >1.2 => >=1.3.0
+        gtlt = '>='
+        if (xm) {
+          M = +M + 1
+          m = 0
+          p = 0
+        } else {
+          m = +m + 1
+          p = 0
+        }
+      } else if (gtlt === '<=') {
+        // <=0.7.x is actually <0.8.0, since any 0.7.x should
+        // pass.  Similarly, <=7.x is actually <8.0.0, etc.
+        gtlt = '<'
+        if (xm) {
+          M = +M + 1
+        } else {
+          m = +m + 1
+        }
+      }
+
+      if (gtlt === '<') {
+        pr = '-0'
+      }
+
+      ret = `${gtlt + M}.${m}.${p}${pr}`
+    } else if (xm) {
+      ret = `>=${M}.0.0${pr} <${+M + 1}.0.0-0`
+    } else if (xp) {
+      ret = `>=${M}.${m}.0${pr
+      } <${M}.${+m + 1}.0-0`
+    }
+
+    debug('xRange return', ret)
+
+    return ret
+  })
+}
+
+// Because * is AND-ed with everything else in the comparator,
+// and '' means "any version", just remove the *s entirely.
+const replaceStars = (comp, options) => {
+  debug('replaceStars', comp, options)
+  // Looseness is ignored here.  star is always as loose as it gets!
+  return comp
+    .trim()
+    .replace(re[t.STAR], '')
+}
+
+const replaceGTE0 = (comp, options) => {
+  debug('replaceGTE0', comp, options)
+  return comp
+    .trim()
+    .replace(re[options.includePrerelease ? t.GTE0PRE : t.GTE0], '')
+}
+
+// This function is passed to string.replace(re[t.HYPHENRANGE])
+// M, m, patch, prerelease, build
+// 1.2 - 3.4.5 => >=1.2.0 <=3.4.5
+// 1.2.3 - 3.4 => >=1.2.0 <3.5.0-0 Any 3.4.x will do
+// 1.2 - 3.4 => >=1.2.0 <3.5.0-0
+// TODO build?
+const hyphenReplace = incPr => ($0,
+  from, fM, fm, fp, fpr, fb,
+  to, tM, tm, tp, tpr) => {
+  if (isX(fM)) {
+    from = ''
+  } else if (isX(fm)) {
+    from = `>=${fM}.0.0${incPr ? '-0' : ''}`
+  } else if (isX(fp)) {
+    from = `>=${fM}.${fm}.0${incPr ? '-0' : ''}`
+  } else if (fpr) {
+    from = `>=${from}`
+  } else {
+    from = `>=${from}${incPr ? '-0' : ''}`
+  }
+
+  if (isX(tM)) {
+    to = ''
+  } else if (isX(tm)) {
+    to = `<${+tM + 1}.0.0-0`
+  } else if (isX(tp)) {
+    to = `<${tM}.${+tm + 1}.0-0`
+  } else if (tpr) {
+    to = `<=${tM}.${tm}.${tp}-${tpr}`
+  } else if (incPr) {
+    to = `<${tM}.${tm}.${+tp + 1}-0`
+  } else {
+    to = `<=${to}`
+  }
+
+  return `${from} ${to}`.trim()
+}
+
+const testSet = (set, version, options) => {
+  for (let i = 0; i < set.length; i++) {
+    if (!set[i].test(version)) {
+      return false
+    }
+  }
+
+  if (version.prerelease.length && !options.includePrerelease) {
+    // Find the set of versions that are allowed to have prereleases
+    // For example, ^1.2.3-pr.1 desugars to >=1.2.3-pr.1 <2.0.0
+    // That should allow `1.2.3-pr.2` to pass.
+    // However, `1.2.4-alpha.notready` should NOT be allowed,
+    // even though it's within the range set by the comparators.
+    for (let i = 0; i < set.length; i++) {
+      debug(set[i].semver)
+      if (set[i].semver === Comparator.ANY) {
+        continue
+      }
+
+      if (set[i].semver.prerelease.length > 0) {
+        const allowed = set[i].semver
+        if (allowed.major === version.major &&
+            allowed.minor === version.minor &&
+            allowed.patch === version.patch) {
+          return true
+        }
+      }
+    }
+
+    // Version has a -pre, but it's not one of the ones we like.
+    return false
+  }
+
+  return true
+}
diff --git a/server/node_modules/semver/classes/semver.js b/server/node_modules/semver/classes/semver.js
new file mode 100644
index 0000000..92254be
--- /dev/null
+++ b/server/node_modules/semver/classes/semver.js
@@ -0,0 +1,333 @@
+'use strict'
+
+const debug = require('../internal/debug')
+const { MAX_LENGTH, MAX_SAFE_INTEGER } = require('../internal/constants')
+const { safeRe: re, t } = require('../internal/re')
+
+const parseOptions = require('../internal/parse-options')
+const { compareIdentifiers } = require('../internal/identifiers')
+class SemVer {
+  constructor (version, options) {
+    options = parseOptions(options)
+
+    if (version instanceof SemVer) {
+      if (version.loose === !!options.loose &&
+        version.includePrerelease === !!options.includePrerelease) {
+        return version
+      } else {
+        version = version.version
+      }
+    } else if (typeof version !== 'string') {
+      throw new TypeError(`Invalid version. Must be a string. Got type "${typeof version}".`)
+    }
+
+    if (version.length > MAX_LENGTH) {
+      throw new TypeError(
+        `version is longer than ${MAX_LENGTH} characters`
+      )
+    }
+
+    debug('SemVer', version, options)
+    this.options = options
+    this.loose = !!options.loose
+    // this isn't actually relevant for versions, but keep it so that we
+    // don't run into trouble passing this.options around.
+    this.includePrerelease = !!options.includePrerelease
+
+    const m = version.trim().match(options.loose ? re[t.LOOSE] : re[t.FULL])
+
+    if (!m) {
+      throw new TypeError(`Invalid Version: ${version}`)
+    }
+
+    this.raw = version
+
+    // these are actually numbers
+    this.major = +m[1]
+    this.minor = +m[2]
+    this.patch = +m[3]
+
+    if (this.major > MAX_SAFE_INTEGER || this.major < 0) {
+      throw new TypeError('Invalid major version')
+    }
+
+    if (this.minor > MAX_SAFE_INTEGER || this.minor < 0) {
+      throw new TypeError('Invalid minor version')
+    }
+
+    if (this.patch > MAX_SAFE_INTEGER || this.patch < 0) {
+      throw new TypeError('Invalid patch version')
+    }
+
+    // numberify any prerelease numeric ids
+    if (!m[4]) {
+      this.prerelease = []
+    } else {
+      this.prerelease = m[4].split('.').map((id) => {
+        if (/^[0-9]+$/.test(id)) {
+          const num = +id
+          if (num >= 0 && num < MAX_SAFE_INTEGER) {
+            return num
+          }
+        }
+        return id
+      })
+    }
+
+    this.build = m[5] ? m[5].split('.') : []
+    this.format()
+  }
+
+  format () {
+    this.version = `${this.major}.${this.minor}.${this.patch}`
+    if (this.prerelease.length) {
+      this.version += `-${this.prerelease.join('.')}`
+    }
+    return this.version
+  }
+
+  toString () {
+    return this.version
+  }
+
+  compare (other) {
+    debug('SemVer.compare', this.version, this.options, other)
+    if (!(other instanceof SemVer)) {
+      if (typeof other === 'string' && other === this.version) {
+        return 0
+      }
+      other = new SemVer(other, this.options)
+    }
+
+    if (other.version === this.version) {
+      return 0
+    }
+
+    return this.compareMain(other) || this.comparePre(other)
+  }
+
+  compareMain (other) {
+    if (!(other instanceof SemVer)) {
+      other = new SemVer(other, this.options)
+    }
+
+    if (this.major < other.major) {
+      return -1
+    }
+    if (this.major > other.major) {
+      return 1
+    }
+    if (this.minor < other.minor) {
+      return -1
+    }
+    if (this.minor > other.minor) {
+      return 1
+    }
+    if (this.patch < other.patch) {
+      return -1
+    }
+    if (this.patch > other.patch) {
+      return 1
+    }
+    return 0
+  }
+
+  comparePre (other) {
+    if (!(other instanceof SemVer)) {
+      other = new SemVer(other, this.options)
+    }
+
+    // NOT having a prerelease is > having one
+    if (this.prerelease.length && !other.prerelease.length) {
+      return -1
+    } else if (!this.prerelease.length && other.prerelease.length) {
+      return 1
+    } else if (!this.prerelease.length && !other.prerelease.length) {
+      return 0
+    }
+
+    let i = 0
+    do {
+      const a = this.prerelease[i]
+      const b = other.prerelease[i]
+      debug('prerelease compare', i, a, b)
+      if (a === undefined && b === undefined) {
+        return 0
+      } else if (b === undefined) {
+        return 1
+      } else if (a === undefined) {
+        return -1
+      } else if (a === b) {
+        continue
+      } else {
+        return compareIdentifiers(a, b)
+      }
+    } while (++i)
+  }
+
+  compareBuild (other) {
+    if (!(other instanceof SemVer)) {
+      other = new SemVer(other, this.options)
+    }
+
+    let i = 0
+    do {
+      const a = this.build[i]
+      const b = other.build[i]
+      debug('build compare', i, a, b)
+      if (a === undefined && b === undefined) {
+        return 0
+      } else if (b === undefined) {
+        return 1
+      } else if (a === undefined) {
+        return -1
+      } else if (a === b) {
+        continue
+      } else {
+        return compareIdentifiers(a, b)
+      }
+    } while (++i)
+  }
+
+  // preminor will bump the version up to the next minor release, and immediately
+  // down to pre-release. premajor and prepatch work the same way.
+  inc (release, identifier, identifierBase) {
+    if (release.startsWith('pre')) {
+      if (!identifier && identifierBase === false) {
+        throw new Error('invalid increment argument: identifier is empty')
+      }
+      // Avoid an invalid semver results
+      if (identifier) {
+        const match = `-${identifier}`.match(this.options.loose ? re[t.PRERELEASELOOSE] : re[t.PRERELEASE])
+        if (!match || match[1] !== identifier) {
+          throw new Error(`invalid identifier: ${identifier}`)
+        }
+      }
+    }
+
+    switch (release) {
+      case 'premajor':
+        this.prerelease.length = 0
+        this.patch = 0
+        this.minor = 0
+        this.major++
+        this.inc('pre', identifier, identifierBase)
+        break
+      case 'preminor':
+        this.prerelease.length = 0
+        this.patch = 0
+        this.minor++
+        this.inc('pre', identifier, identifierBase)
+        break
+      case 'prepatch':
+        // If this is already a prerelease, it will bump to the next version
+        // drop any prereleases that might already exist, since they are not
+        // relevant at this point.
+        this.prerelease.length = 0
+        this.inc('patch', identifier, identifierBase)
+        this.inc('pre', identifier, identifierBase)
+        break
+      // If the input is a non-prerelease version, this acts the same as
+      // prepatch.
+      case 'prerelease':
+        if (this.prerelease.length === 0) {
+          this.inc('patch', identifier, identifierBase)
+        }
+        this.inc('pre', identifier, identifierBase)
+        break
+      case 'release':
+        if (this.prerelease.length === 0) {
+          throw new Error(`version ${this.raw} is not a prerelease`)
+        }
+        this.prerelease.length = 0
+        break
+
+      case 'major':
+        // If this is a pre-major version, bump up to the same major version.
+        // Otherwise increment major.
+        // 1.0.0-5 bumps to 1.0.0
+        // 1.1.0 bumps to 2.0.0
+        if (
+          this.minor !== 0 ||
+          this.patch !== 0 ||
+          this.prerelease.length === 0
+        ) {
+          this.major++
+        }
+        this.minor = 0
+        this.patch = 0
+        this.prerelease = []
+        break
+      case 'minor':
+        // If this is a pre-minor version, bump up to the same minor version.
+        // Otherwise increment minor.
+        // 1.2.0-5 bumps to 1.2.0
+        // 1.2.1 bumps to 1.3.0
+        if (this.patch !== 0 || this.prerelease.length === 0) {
+          this.minor++
+        }
+        this.patch = 0
+        this.prerelease = []
+        break
+      case 'patch':
+        // If this is not a pre-release version, it will increment the patch.
+        // If it is a pre-release it will bump up to the same patch version.
+        // 1.2.0-5 patches to 1.2.0
+        // 1.2.0 patches to 1.2.1
+        if (this.prerelease.length === 0) {
+          this.patch++
+        }
+        this.prerelease = []
+        break
+      // This probably shouldn't be used publicly.
+      // 1.0.0 'pre' would become 1.0.0-0 which is the wrong direction.
+      case 'pre': {
+        const base = Number(identifierBase) ? 1 : 0
+
+        if (this.prerelease.length === 0) {
+          this.prerelease = [base]
+        } else {
+          let i = this.prerelease.length
+          while (--i >= 0) {
+            if (typeof this.prerelease[i] === 'number') {
+              this.prerelease[i]++
+              i = -2
+            }
+          }
+          if (i === -1) {
+            // didn't increment anything
+            if (identifier === this.prerelease.join('.') && identifierBase === false) {
+              throw new Error('invalid increment argument: identifier already exists')
+            }
+            this.prerelease.push(base)
+          }
+        }
+        if (identifier) {
+          // 1.2.0-beta.1 bumps to 1.2.0-beta.2,
+          // 1.2.0-beta.fooblz or 1.2.0-beta bumps to 1.2.0-beta.0
+          let prerelease = [identifier, base]
+          if (identifierBase === false) {
+            prerelease = [identifier]
+          }
+          if (compareIdentifiers(this.prerelease[0], identifier) === 0) {
+            if (isNaN(this.prerelease[1])) {
+              this.prerelease = prerelease
+            }
+          } else {
+            this.prerelease = prerelease
+          }
+        }
+        break
+      }
+      default:
+        throw new Error(`invalid increment argument: ${release}`)
+    }
+    this.raw = this.format()
+    if (this.build.length) {
+      this.raw += `+${this.build.join('.')}`
+    }
+    return this
+  }
+}
+
+module.exports = SemVer
diff --git a/server/node_modules/semver/functions/clean.js b/server/node_modules/semver/functions/clean.js
new file mode 100644
index 0000000..79703d6
--- /dev/null
+++ b/server/node_modules/semver/functions/clean.js
@@ -0,0 +1,8 @@
+'use strict'
+
+const parse = require('./parse')
+const clean = (version, options) => {
+  const s = parse(version.trim().replace(/^[=v]+/, ''), options)
+  return s ? s.version : null
+}
+module.exports = clean
diff --git a/server/node_modules/semver/functions/cmp.js b/server/node_modules/semver/functions/cmp.js
new file mode 100644
index 0000000..77487dc
--- /dev/null
+++ b/server/node_modules/semver/functions/cmp.js
@@ -0,0 +1,54 @@
+'use strict'
+
+const eq = require('./eq')
+const neq = require('./neq')
+const gt = require('./gt')
+const gte = require('./gte')
+const lt = require('./lt')
+const lte = require('./lte')
+
+const cmp = (a, op, b, loose) => {
+  switch (op) {
+    case '===':
+      if (typeof a === 'object') {
+        a = a.version
+      }
+      if (typeof b === 'object') {
+        b = b.version
+      }
+      return a === b
+
+    case '!==':
+      if (typeof a === 'object') {
+        a = a.version
+      }
+      if (typeof b === 'object') {
+        b = b.version
+      }
+      return a !== b
+
+    case '':
+    case '=':
+    case '==':
+      return eq(a, b, loose)
+
+    case '!=':
+      return neq(a, b, loose)
+
+    case '>':
+      return gt(a, b, loose)
+
+    case '>=':
+      return gte(a, b, loose)
+
+    case '<':
+      return lt(a, b, loose)
+
+    case '<=':
+      return lte(a, b, loose)
+
+    default:
+      throw new TypeError(`Invalid operator: ${op}`)
+  }
+}
+module.exports = cmp
diff --git a/server/node_modules/semver/functions/coerce.js b/server/node_modules/semver/functions/coerce.js
new file mode 100644
index 0000000..cfe0275
--- /dev/null
+++ b/server/node_modules/semver/functions/coerce.js
@@ -0,0 +1,62 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const parse = require('./parse')
+const { safeRe: re, t } = require('../internal/re')
+
+const coerce = (version, options) => {
+  if (version instanceof SemVer) {
+    return version
+  }
+
+  if (typeof version === 'number') {
+    version = String(version)
+  }
+
+  if (typeof version !== 'string') {
+    return null
+  }
+
+  options = options || {}
+
+  let match = null
+  if (!options.rtl) {
+    match = version.match(options.includePrerelease ? re[t.COERCEFULL] : re[t.COERCE])
+  } else {
+    // Find the right-most coercible string that does not share
+    // a terminus with a more left-ward coercible string.
+    // Eg, '1.2.3.4' wants to coerce '2.3.4', not '3.4' or '4'
+    // With includePrerelease option set, '1.2.3.4-rc' wants to coerce '2.3.4-rc', not '2.3.4'
+    //
+    // Walk through the string checking with a /g regexp
+    // Manually set the index so as to pick up overlapping matches.
+    // Stop when we get a match that ends at the string end, since no
+    // coercible string can be more right-ward without the same terminus.
+    const coerceRtlRegex = options.includePrerelease ? re[t.COERCERTLFULL] : re[t.COERCERTL]
+    let next
+    while ((next = coerceRtlRegex.exec(version)) &&
+        (!match || match.index + match[0].length !== version.length)
+    ) {
+      if (!match ||
+            next.index + next[0].length !== match.index + match[0].length) {
+        match = next
+      }
+      coerceRtlRegex.lastIndex = next.index + next[1].length + next[2].length
+    }
+    // leave it in a clean state
+    coerceRtlRegex.lastIndex = -1
+  }
+
+  if (match === null) {
+    return null
+  }
+
+  const major = match[2]
+  const minor = match[3] || '0'
+  const patch = match[4] || '0'
+  const prerelease = options.includePrerelease && match[5] ? `-${match[5]}` : ''
+  const build = options.includePrerelease && match[6] ? `+${match[6]}` : ''
+
+  return parse(`${major}.${minor}.${patch}${prerelease}${build}`, options)
+}
+module.exports = coerce
diff --git a/server/node_modules/semver/functions/compare-build.js b/server/node_modules/semver/functions/compare-build.js
new file mode 100644
index 0000000..99157cf
--- /dev/null
+++ b/server/node_modules/semver/functions/compare-build.js
@@ -0,0 +1,9 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const compareBuild = (a, b, loose) => {
+  const versionA = new SemVer(a, loose)
+  const versionB = new SemVer(b, loose)
+  return versionA.compare(versionB) || versionA.compareBuild(versionB)
+}
+module.exports = compareBuild
diff --git a/server/node_modules/semver/functions/compare-loose.js b/server/node_modules/semver/functions/compare-loose.js
new file mode 100644
index 0000000..7531634
--- /dev/null
+++ b/server/node_modules/semver/functions/compare-loose.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compare = require('./compare')
+const compareLoose = (a, b) => compare(a, b, true)
+module.exports = compareLoose
diff --git a/server/node_modules/semver/functions/compare.js b/server/node_modules/semver/functions/compare.js
new file mode 100644
index 0000000..63d8090
--- /dev/null
+++ b/server/node_modules/semver/functions/compare.js
@@ -0,0 +1,7 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const compare = (a, b, loose) =>
+  new SemVer(a, loose).compare(new SemVer(b, loose))
+
+module.exports = compare
diff --git a/server/node_modules/semver/functions/diff.js b/server/node_modules/semver/functions/diff.js
new file mode 100644
index 0000000..c99ab51
--- /dev/null
+++ b/server/node_modules/semver/functions/diff.js
@@ -0,0 +1,60 @@
+'use strict'
+
+const parse = require('./parse.js')
+
+const diff = (version1, version2) => {
+  const v1 = parse(version1, null, true)
+  const v2 = parse(version2, null, true)
+  const comparison = v1.compare(v2)
+
+  if (comparison === 0) {
+    return null
+  }
+
+  const v1Higher = comparison > 0
+  const highVersion = v1Higher ? v1 : v2
+  const lowVersion = v1Higher ? v2 : v1
+  const highHasPre = !!highVersion.prerelease.length
+  const lowHasPre = !!lowVersion.prerelease.length
+
+  if (lowHasPre && !highHasPre) {
+    // Going from prerelease -> no prerelease requires some special casing
+
+    // If the low version has only a major, then it will always be a major
+    // Some examples:
+    // 1.0.0-1 -> 1.0.0
+    // 1.0.0-1 -> 1.1.1
+    // 1.0.0-1 -> 2.0.0
+    if (!lowVersion.patch && !lowVersion.minor) {
+      return 'major'
+    }
+
+    // If the main part has no difference
+    if (lowVersion.compareMain(highVersion) === 0) {
+      if (lowVersion.minor && !lowVersion.patch) {
+        return 'minor'
+      }
+      return 'patch'
+    }
+  }
+
+  // add the `pre` prefix if we are going to a prerelease version
+  const prefix = highHasPre ? 'pre' : ''
+
+  if (v1.major !== v2.major) {
+    return prefix + 'major'
+  }
+
+  if (v1.minor !== v2.minor) {
+    return prefix + 'minor'
+  }
+
+  if (v1.patch !== v2.patch) {
+    return prefix + 'patch'
+  }
+
+  // high and low are prereleases
+  return 'prerelease'
+}
+
+module.exports = diff
diff --git a/server/node_modules/semver/functions/eq.js b/server/node_modules/semver/functions/eq.js
new file mode 100644
index 0000000..5f0eead
--- /dev/null
+++ b/server/node_modules/semver/functions/eq.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compare = require('./compare')
+const eq = (a, b, loose) => compare(a, b, loose) === 0
+module.exports = eq
diff --git a/server/node_modules/semver/functions/gt.js b/server/node_modules/semver/functions/gt.js
new file mode 100644
index 0000000..84a57dd
--- /dev/null
+++ b/server/node_modules/semver/functions/gt.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compare = require('./compare')
+const gt = (a, b, loose) => compare(a, b, loose) > 0
+module.exports = gt
diff --git a/server/node_modules/semver/functions/gte.js b/server/node_modules/semver/functions/gte.js
new file mode 100644
index 0000000..7c52bdf
--- /dev/null
+++ b/server/node_modules/semver/functions/gte.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compare = require('./compare')
+const gte = (a, b, loose) => compare(a, b, loose) >= 0
+module.exports = gte
diff --git a/server/node_modules/semver/functions/inc.js b/server/node_modules/semver/functions/inc.js
new file mode 100644
index 0000000..ff999e9
--- /dev/null
+++ b/server/node_modules/semver/functions/inc.js
@@ -0,0 +1,21 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+
+const inc = (version, release, options, identifier, identifierBase) => {
+  if (typeof (options) === 'string') {
+    identifierBase = identifier
+    identifier = options
+    options = undefined
+  }
+
+  try {
+    return new SemVer(
+      version instanceof SemVer ? version.version : version,
+      options
+    ).inc(release, identifier, identifierBase).version
+  } catch (er) {
+    return null
+  }
+}
+module.exports = inc
diff --git a/server/node_modules/semver/functions/lt.js b/server/node_modules/semver/functions/lt.js
new file mode 100644
index 0000000..2fb32a0
--- /dev/null
+++ b/server/node_modules/semver/functions/lt.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compare = require('./compare')
+const lt = (a, b, loose) => compare(a, b, loose) < 0
+module.exports = lt
diff --git a/server/node_modules/semver/functions/lte.js b/server/node_modules/semver/functions/lte.js
new file mode 100644
index 0000000..da9ee8f
--- /dev/null
+++ b/server/node_modules/semver/functions/lte.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compare = require('./compare')
+const lte = (a, b, loose) => compare(a, b, loose) <= 0
+module.exports = lte
diff --git a/server/node_modules/semver/functions/major.js b/server/node_modules/semver/functions/major.js
new file mode 100644
index 0000000..e6d08dc
--- /dev/null
+++ b/server/node_modules/semver/functions/major.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const major = (a, loose) => new SemVer(a, loose).major
+module.exports = major
diff --git a/server/node_modules/semver/functions/minor.js b/server/node_modules/semver/functions/minor.js
new file mode 100644
index 0000000..9e70ffd
--- /dev/null
+++ b/server/node_modules/semver/functions/minor.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const minor = (a, loose) => new SemVer(a, loose).minor
+module.exports = minor
diff --git a/server/node_modules/semver/functions/neq.js b/server/node_modules/semver/functions/neq.js
new file mode 100644
index 0000000..84326b7
--- /dev/null
+++ b/server/node_modules/semver/functions/neq.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compare = require('./compare')
+const neq = (a, b, loose) => compare(a, b, loose) !== 0
+module.exports = neq
diff --git a/server/node_modules/semver/functions/parse.js b/server/node_modules/semver/functions/parse.js
new file mode 100644
index 0000000..d544d33
--- /dev/null
+++ b/server/node_modules/semver/functions/parse.js
@@ -0,0 +1,18 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const parse = (version, options, throwErrors = false) => {
+  if (version instanceof SemVer) {
+    return version
+  }
+  try {
+    return new SemVer(version, options)
+  } catch (er) {
+    if (!throwErrors) {
+      return null
+    }
+    throw er
+  }
+}
+
+module.exports = parse
diff --git a/server/node_modules/semver/functions/patch.js b/server/node_modules/semver/functions/patch.js
new file mode 100644
index 0000000..7675162
--- /dev/null
+++ b/server/node_modules/semver/functions/patch.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const patch = (a, loose) => new SemVer(a, loose).patch
+module.exports = patch
diff --git a/server/node_modules/semver/functions/prerelease.js b/server/node_modules/semver/functions/prerelease.js
new file mode 100644
index 0000000..b8fe1db
--- /dev/null
+++ b/server/node_modules/semver/functions/prerelease.js
@@ -0,0 +1,8 @@
+'use strict'
+
+const parse = require('./parse')
+const prerelease = (version, options) => {
+  const parsed = parse(version, options)
+  return (parsed && parsed.prerelease.length) ? parsed.prerelease : null
+}
+module.exports = prerelease
diff --git a/server/node_modules/semver/functions/rcompare.js b/server/node_modules/semver/functions/rcompare.js
new file mode 100644
index 0000000..8e1c222
--- /dev/null
+++ b/server/node_modules/semver/functions/rcompare.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compare = require('./compare')
+const rcompare = (a, b, loose) => compare(b, a, loose)
+module.exports = rcompare
diff --git a/server/node_modules/semver/functions/rsort.js b/server/node_modules/semver/functions/rsort.js
new file mode 100644
index 0000000..5d3d200
--- /dev/null
+++ b/server/node_modules/semver/functions/rsort.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compareBuild = require('./compare-build')
+const rsort = (list, loose) => list.sort((a, b) => compareBuild(b, a, loose))
+module.exports = rsort
diff --git a/server/node_modules/semver/functions/satisfies.js b/server/node_modules/semver/functions/satisfies.js
new file mode 100644
index 0000000..a0264a2
--- /dev/null
+++ b/server/node_modules/semver/functions/satisfies.js
@@ -0,0 +1,12 @@
+'use strict'
+
+const Range = require('../classes/range')
+const satisfies = (version, range, options) => {
+  try {
+    range = new Range(range, options)
+  } catch (er) {
+    return false
+  }
+  return range.test(version)
+}
+module.exports = satisfies
diff --git a/server/node_modules/semver/functions/sort.js b/server/node_modules/semver/functions/sort.js
new file mode 100644
index 0000000..edb24b1
--- /dev/null
+++ b/server/node_modules/semver/functions/sort.js
@@ -0,0 +1,5 @@
+'use strict'
+
+const compareBuild = require('./compare-build')
+const sort = (list, loose) => list.sort((a, b) => compareBuild(a, b, loose))
+module.exports = sort
diff --git a/server/node_modules/semver/functions/valid.js b/server/node_modules/semver/functions/valid.js
new file mode 100644
index 0000000..0db67ed
--- /dev/null
+++ b/server/node_modules/semver/functions/valid.js
@@ -0,0 +1,8 @@
+'use strict'
+
+const parse = require('./parse')
+const valid = (version, options) => {
+  const v = parse(version, options)
+  return v ? v.version : null
+}
+module.exports = valid
diff --git a/server/node_modules/semver/index.js b/server/node_modules/semver/index.js
new file mode 100644
index 0000000..285662a
--- /dev/null
+++ b/server/node_modules/semver/index.js
@@ -0,0 +1,91 @@
+'use strict'
+
+// just pre-load all the stuff that index.js lazily exports
+const internalRe = require('./internal/re')
+const constants = require('./internal/constants')
+const SemVer = require('./classes/semver')
+const identifiers = require('./internal/identifiers')
+const parse = require('./functions/parse')
+const valid = require('./functions/valid')
+const clean = require('./functions/clean')
+const inc = require('./functions/inc')
+const diff = require('./functions/diff')
+const major = require('./functions/major')
+const minor = require('./functions/minor')
+const patch = require('./functions/patch')
+const prerelease = require('./functions/prerelease')
+const compare = require('./functions/compare')
+const rcompare = require('./functions/rcompare')
+const compareLoose = require('./functions/compare-loose')
+const compareBuild = require('./functions/compare-build')
+const sort = require('./functions/sort')
+const rsort = require('./functions/rsort')
+const gt = require('./functions/gt')
+const lt = require('./functions/lt')
+const eq = require('./functions/eq')
+const neq = require('./functions/neq')
+const gte = require('./functions/gte')
+const lte = require('./functions/lte')
+const cmp = require('./functions/cmp')
+const coerce = require('./functions/coerce')
+const Comparator = require('./classes/comparator')
+const Range = require('./classes/range')
+const satisfies = require('./functions/satisfies')
+const toComparators = require('./ranges/to-comparators')
+const maxSatisfying = require('./ranges/max-satisfying')
+const minSatisfying = require('./ranges/min-satisfying')
+const minVersion = require('./ranges/min-version')
+const validRange = require('./ranges/valid')
+const outside = require('./ranges/outside')
+const gtr = require('./ranges/gtr')
+const ltr = require('./ranges/ltr')
+const intersects = require('./ranges/intersects')
+const simplifyRange = require('./ranges/simplify')
+const subset = require('./ranges/subset')
+module.exports = {
+  parse,
+  valid,
+  clean,
+  inc,
+  diff,
+  major,
+  minor,
+  patch,
+  prerelease,
+  compare,
+  rcompare,
+  compareLoose,
+  compareBuild,
+  sort,
+  rsort,
+  gt,
+  lt,
+  eq,
+  neq,
+  gte,
+  lte,
+  cmp,
+  coerce,
+  Comparator,
+  Range,
+  satisfies,
+  toComparators,
+  maxSatisfying,
+  minSatisfying,
+  minVersion,
+  validRange,
+  outside,
+  gtr,
+  ltr,
+  intersects,
+  simplifyRange,
+  subset,
+  SemVer,
+  re: internalRe.re,
+  src: internalRe.src,
+  tokens: internalRe.t,
+  SEMVER_SPEC_VERSION: constants.SEMVER_SPEC_VERSION,
+  RELEASE_TYPES: constants.RELEASE_TYPES,
+  compareIdentifiers: identifiers.compareIdentifiers,
+  rcompareIdentifiers: identifiers.rcompareIdentifiers,
+}
diff --git a/server/node_modules/semver/internal/constants.js b/server/node_modules/semver/internal/constants.js
new file mode 100644
index 0000000..6d1db91
--- /dev/null
+++ b/server/node_modules/semver/internal/constants.js
@@ -0,0 +1,37 @@
+'use strict'
+
+// Note: this is the semver.org version of the spec that it implements
+// Not necessarily the package version of this code.
+const SEMVER_SPEC_VERSION = '2.0.0'
+
+const MAX_LENGTH = 256
+const MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER ||
+/* istanbul ignore next */ 9007199254740991
+
+// Max safe segment length for coercion.
+const MAX_SAFE_COMPONENT_LENGTH = 16
+
+// Max safe length for a build identifier. The max length minus 6 characters for
+// the shortest version with a build 0.0.0+BUILD.
+const MAX_SAFE_BUILD_LENGTH = MAX_LENGTH - 6
+
+const RELEASE_TYPES = [
+  'major',
+  'premajor',
+  'minor',
+  'preminor',
+  'patch',
+  'prepatch',
+  'prerelease',
+]
+
+module.exports = {
+  MAX_LENGTH,
+  MAX_SAFE_COMPONENT_LENGTH,
+  MAX_SAFE_BUILD_LENGTH,
+  MAX_SAFE_INTEGER,
+  RELEASE_TYPES,
+  SEMVER_SPEC_VERSION,
+  FLAG_INCLUDE_PRERELEASE: 0b001,
+  FLAG_LOOSE: 0b010,
+}
diff --git a/server/node_modules/semver/internal/debug.js b/server/node_modules/semver/internal/debug.js
new file mode 100644
index 0000000..20d1e9d
--- /dev/null
+++ b/server/node_modules/semver/internal/debug.js
@@ -0,0 +1,11 @@
+'use strict'
+
+const debug = (
+  typeof process === 'object' &&
+  process.env &&
+  process.env.NODE_DEBUG &&
+  /\bsemver\b/i.test(process.env.NODE_DEBUG)
+) ? (...args) => console.error('SEMVER', ...args)
+  : () => {}
+
+module.exports = debug
diff --git a/server/node_modules/semver/internal/identifiers.js b/server/node_modules/semver/internal/identifiers.js
new file mode 100644
index 0000000..d053472
--- /dev/null
+++ b/server/node_modules/semver/internal/identifiers.js
@@ -0,0 +1,29 @@
+'use strict'
+
+const numeric = /^[0-9]+$/
+const compareIdentifiers = (a, b) => {
+  if (typeof a === 'number' && typeof b === 'number') {
+    return a === b ? 0 : a < b ? -1 : 1
+  }
+
+  const anum = numeric.test(a)
+  const bnum = numeric.test(b)
+
+  if (anum && bnum) {
+    a = +a
+    b = +b
+  }
+
+  return a === b ? 0
+    : (anum && !bnum) ? -1
+    : (bnum && !anum) ? 1
+    : a < b ? -1
+    : 1
+}
+
+const rcompareIdentifiers = (a, b) => compareIdentifiers(b, a)
+
+module.exports = {
+  compareIdentifiers,
+  rcompareIdentifiers,
+}
diff --git a/server/node_modules/semver/internal/lrucache.js b/server/node_modules/semver/internal/lrucache.js
new file mode 100644
index 0000000..b8bf526
--- /dev/null
+++ b/server/node_modules/semver/internal/lrucache.js
@@ -0,0 +1,42 @@
+'use strict'
+
+class LRUCache {
+  constructor () {
+    this.max = 1000
+    this.map = new Map()
+  }
+
+  get (key) {
+    const value = this.map.get(key)
+    if (value === undefined) {
+      return undefined
+    } else {
+      // Remove the key from the map and add it to the end
+      this.map.delete(key)
+      this.map.set(key, value)
+      return value
+    }
+  }
+
+  delete (key) {
+    return this.map.delete(key)
+  }
+
+  set (key, value) {
+    const deleted = this.delete(key)
+
+    if (!deleted && value !== undefined) {
+      // If cache is full, delete the least recently used item
+      if (this.map.size >= this.max) {
+        const firstKey = this.map.keys().next().value
+        this.delete(firstKey)
+      }
+
+      this.map.set(key, value)
+    }
+
+    return this
+  }
+}
+
+module.exports = LRUCache
diff --git a/server/node_modules/semver/internal/parse-options.js b/server/node_modules/semver/internal/parse-options.js
new file mode 100644
index 0000000..5295454
--- /dev/null
+++ b/server/node_modules/semver/internal/parse-options.js
@@ -0,0 +1,17 @@
+'use strict'
+
+// parse out just the options we care about
+const looseOption = Object.freeze({ loose: true })
+const emptyOpts = Object.freeze({ })
+const parseOptions = options => {
+  if (!options) {
+    return emptyOpts
+  }
+
+  if (typeof options !== 'object') {
+    return looseOption
+  }
+
+  return options
+}
+module.exports = parseOptions
diff --git a/server/node_modules/semver/internal/re.js b/server/node_modules/semver/internal/re.js
new file mode 100644
index 0000000..639fca8
--- /dev/null
+++ b/server/node_modules/semver/internal/re.js
@@ -0,0 +1,223 @@
+'use strict'
+
+const {
+  MAX_SAFE_COMPONENT_LENGTH,
+  MAX_SAFE_BUILD_LENGTH,
+  MAX_LENGTH,
+} = require('./constants')
+const debug = require('./debug')
+exports = module.exports = {}
+
+// The actual regexps go on exports.re
+const re = exports.re = []
+const safeRe = exports.safeRe = []
+const src = exports.src = []
+const safeSrc = exports.safeSrc = []
+const t = exports.t = {}
+let R = 0
+
+const LETTERDASHNUMBER = '[a-zA-Z0-9-]'
+
+// Replace some greedy regex tokens to prevent regex dos issues. These regex are
+// used internally via the safeRe object since all inputs in this library get
+// normalized first to trim and collapse all extra whitespace. The original
+// regexes are exported for userland consumption and lower level usage. A
+// future breaking change could export the safer regex only with a note that
+// all input should have extra whitespace removed.
+const safeRegexReplacements = [
+  ['\\s', 1],
+  ['\\d', MAX_LENGTH],
+  [LETTERDASHNUMBER, MAX_SAFE_BUILD_LENGTH],
+]
+
+const makeSafeRegex = (value) => {
+  for (const [token, max] of safeRegexReplacements) {
+    value = value
+      .split(`${token}*`).join(`${token}{0,${max}}`)
+      .split(`${token}+`).join(`${token}{1,${max}}`)
+  }
+  return value
+}
+
+const createToken = (name, value, isGlobal) => {
+  const safe = makeSafeRegex(value)
+  const index = R++
+  debug(name, index, value)
+  t[name] = index
+  src[index] = value
+  safeSrc[index] = safe
+  re[index] = new RegExp(value, isGlobal ? 'g' : undefined)
+  safeRe[index] = new RegExp(safe, isGlobal ? 'g' : undefined)
+}
+
+// The following Regular Expressions can be used for tokenizing,
+// validating, and parsing SemVer version strings.
+
+// ## Numeric Identifier
+// A single `0`, or a non-zero digit followed by zero or more digits.
+
+createToken('NUMERICIDENTIFIER', '0|[1-9]\\d*')
+createToken('NUMERICIDENTIFIERLOOSE', '\\d+')
+
+// ## Non-numeric Identifier
+// Zero or more digits, followed by a letter or hyphen, and then zero or
+// more letters, digits, or hyphens.
+
+createToken('NONNUMERICIDENTIFIER', `\\d*[a-zA-Z-]${LETTERDASHNUMBER}*`)
+
+// ## Main Version
+// Three dot-separated numeric identifiers.
+
+createToken('MAINVERSION', `(${src[t.NUMERICIDENTIFIER]})\\.` +
+                   `(${src[t.NUMERICIDENTIFIER]})\\.` +
+                   `(${src[t.NUMERICIDENTIFIER]})`)
+
+createToken('MAINVERSIONLOOSE', `(${src[t.NUMERICIDENTIFIERLOOSE]})\\.` +
+                        `(${src[t.NUMERICIDENTIFIERLOOSE]})\\.` +
+                        `(${src[t.NUMERICIDENTIFIERLOOSE]})`)
+
+// ## Pre-release Version Identifier
+// A numeric identifier, or a non-numeric identifier.
+// Non-numeric identifiers include numeric identifiers but can be longer.
+// Therefore non-numeric identifiers must go first.
+
+createToken('PRERELEASEIDENTIFIER', `(?:${src[t.NONNUMERICIDENTIFIER]
+}|${src[t.NUMERICIDENTIFIER]})`)
+
+createToken('PRERELEASEIDENTIFIERLOOSE', `(?:${src[t.NONNUMERICIDENTIFIER]
+}|${src[t.NUMERICIDENTIFIERLOOSE]})`)
+
+// ## Pre-release Version
+// Hyphen, followed by one or more dot-separated pre-release version
+// identifiers.
+
+createToken('PRERELEASE', `(?:-(${src[t.PRERELEASEIDENTIFIER]
+}(?:\\.${src[t.PRERELEASEIDENTIFIER]})*))`)
+
+createToken('PRERELEASELOOSE', `(?:-?(${src[t.PRERELEASEIDENTIFIERLOOSE]
+}(?:\\.${src[t.PRERELEASEIDENTIFIERLOOSE]})*))`)
+
+// ## Build Metadata Identifier
+// Any combination of digits, letters, or hyphens.
+
+createToken('BUILDIDENTIFIER', `${LETTERDASHNUMBER}+`)
+
+// ## Build Metadata
+// Plus sign, followed by one or more period-separated build metadata
+// identifiers.
+
+createToken('BUILD', `(?:\\+(${src[t.BUILDIDENTIFIER]
+}(?:\\.${src[t.BUILDIDENTIFIER]})*))`)
+
+// ## Full Version String
+// A main version, followed optionally by a pre-release version and
+// build metadata.
+
+// Note that the only major, minor, patch, and pre-release sections of
+// the version string are capturing groups.  The build metadata is not a
+// capturing group, because it should not ever be used in version
+// comparison.
+
+createToken('FULLPLAIN', `v?${src[t.MAINVERSION]
+}${src[t.PRERELEASE]}?${
+  src[t.BUILD]}?`)
+
+createToken('FULL', `^${src[t.FULLPLAIN]}$`)
+
+// like full, but allows v1.2.3 and =1.2.3, which people do sometimes.
+// also, 1.0.0alpha1 (prerelease without the hyphen) which is pretty
+// common in the npm registry.
+createToken('LOOSEPLAIN', `[v=\\s]*${src[t.MAINVERSIONLOOSE]
+}${src[t.PRERELEASELOOSE]}?${
+  src[t.BUILD]}?`)
+
+createToken('LOOSE', `^${src[t.LOOSEPLAIN]}$`)
+
+createToken('GTLT', '((?:<|>)?=?)')
+
+// Something like "2.*" or "1.2.x".
+// Note that "x.x" is a valid xRange identifer, meaning "any version"
+// Only the first item is strictly required.
+createToken('XRANGEIDENTIFIERLOOSE', `${src[t.NUMERICIDENTIFIERLOOSE]}|x|X|\\*`)
+createToken('XRANGEIDENTIFIER', `${src[t.NUMERICIDENTIFIER]}|x|X|\\*`)
+
+createToken('XRANGEPLAIN', `[v=\\s]*(${src[t.XRANGEIDENTIFIER]})` +
+                   `(?:\\.(${src[t.XRANGEIDENTIFIER]})` +
+                   `(?:\\.(${src[t.XRANGEIDENTIFIER]})` +
+                   `(?:${src[t.PRERELEASE]})?${
+                     src[t.BUILD]}?` +
+                   `)?)?`)
+
+createToken('XRANGEPLAINLOOSE', `[v=\\s]*(${src[t.XRANGEIDENTIFIERLOOSE]})` +
+                        `(?:\\.(${src[t.XRANGEIDENTIFIERLOOSE]})` +
+                        `(?:\\.(${src[t.XRANGEIDENTIFIERLOOSE]})` +
+                        `(?:${src[t.PRERELEASELOOSE]})?${
+                          src[t.BUILD]}?` +
+                        `)?)?`)
+
+createToken('XRANGE', `^${src[t.GTLT]}\\s*${src[t.XRANGEPLAIN]}$`)
+createToken('XRANGELOOSE', `^${src[t.GTLT]}\\s*${src[t.XRANGEPLAINLOOSE]}$`)
+
+// Coercion.
+// Extract anything that could conceivably be a part of a valid semver
+createToken('COERCEPLAIN', `${'(^|[^\\d])' +
+              '(\\d{1,'}${MAX_SAFE_COMPONENT_LENGTH}})` +
+              `(?:\\.(\\d{1,${MAX_SAFE_COMPONENT_LENGTH}}))?` +
+              `(?:\\.(\\d{1,${MAX_SAFE_COMPONENT_LENGTH}}))?`)
+createToken('COERCE', `${src[t.COERCEPLAIN]}(?:$|[^\\d])`)
+createToken('COERCEFULL', src[t.COERCEPLAIN] +
+              `(?:${src[t.PRERELEASE]})?` +
+              `(?:${src[t.BUILD]})?` +
+              `(?:$|[^\\d])`)
+createToken('COERCERTL', src[t.COERCE], true)
+createToken('COERCERTLFULL', src[t.COERCEFULL], true)
+
+// Tilde ranges.
+// Meaning is "reasonably at or greater than"
+createToken('LONETILDE', '(?:~>?)')
+
+createToken('TILDETRIM', `(\\s*)${src[t.LONETILDE]}\\s+`, true)
+exports.tildeTrimReplace = '$1~'
+
+createToken('TILDE', `^${src[t.LONETILDE]}${src[t.XRANGEPLAIN]}$`)
+createToken('TILDELOOSE', `^${src[t.LONETILDE]}${src[t.XRANGEPLAINLOOSE]}$`)
+
+// Caret ranges.
+// Meaning is "at least and backwards compatible with"
+createToken('LONECARET', '(?:\\^)')
+
+createToken('CARETTRIM', `(\\s*)${src[t.LONECARET]}\\s+`, true)
+exports.caretTrimReplace = '$1^'
+
+createToken('CARET', `^${src[t.LONECARET]}${src[t.XRANGEPLAIN]}$`)
+createToken('CARETLOOSE', `^${src[t.LONECARET]}${src[t.XRANGEPLAINLOOSE]}$`)
+
+// A simple gt/lt/eq thing, or just "" to indicate "any version"
+createToken('COMPARATORLOOSE', `^${src[t.GTLT]}\\s*(${src[t.LOOSEPLAIN]})$|^$`)
+createToken('COMPARATOR', `^${src[t.GTLT]}\\s*(${src[t.FULLPLAIN]})$|^$`)
+
+// An expression to strip any whitespace between the gtlt and the thing
+// it modifies, so that `> 1.2.3` ==> `>1.2.3`
+createToken('COMPARATORTRIM', `(\\s*)${src[t.GTLT]
+}\\s*(${src[t.LOOSEPLAIN]}|${src[t.XRANGEPLAIN]})`, true)
+exports.comparatorTrimReplace = '$1$2$3'
+
+// Something like `1.2.3 - 1.2.4`
+// Note that these all use the loose form, because they'll be
+// checked against either the strict or loose comparator form
+// later.
+createToken('HYPHENRANGE', `^\\s*(${src[t.XRANGEPLAIN]})` +
+                   `\\s+-\\s+` +
+                   `(${src[t.XRANGEPLAIN]})` +
+                   `\\s*$`)
+
+createToken('HYPHENRANGELOOSE', `^\\s*(${src[t.XRANGEPLAINLOOSE]})` +
+                        `\\s+-\\s+` +
+                        `(${src[t.XRANGEPLAINLOOSE]})` +
+                        `\\s*$`)
+
+// Star ranges basically just allow anything at all.
+createToken('STAR', '(<|>)?=?\\s*\\*')
+// >=0.0.0 is like a star
+createToken('GTE0', '^\\s*>=\\s*0\\.0\\.0\\s*$')
+createToken('GTE0PRE', '^\\s*>=\\s*0\\.0\\.0-0\\s*$')
diff --git a/server/node_modules/semver/package.json b/server/node_modules/semver/package.json
new file mode 100644
index 0000000..a84de91
--- /dev/null
+++ b/server/node_modules/semver/package.json
@@ -0,0 +1,78 @@
+{
+  "name": "semver",
+  "version": "7.7.4",
+  "description": "The semantic version parser used by npm.",
+  "main": "index.js",
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "lint": "npm run eslint",
+    "postlint": "template-oss-check",
+    "lintfix": "npm run eslint -- --fix",
+    "posttest": "npm run lint",
+    "template-oss-apply": "template-oss-apply --force",
+    "eslint": "eslint \"**/*.{js,cjs,ts,mjs,jsx,tsx}\""
+  },
+  "devDependencies": {
+    "@npmcli/eslint-config": "^6.0.0",
+    "@npmcli/template-oss": "4.29.0",
+    "benchmark": "^2.1.4",
+    "tap": "^16.0.0"
+  },
+  "license": "ISC",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/npm/node-semver.git"
+  },
+  "bin": {
+    "semver": "bin/semver.js"
+  },
+  "files": [
+    "bin/",
+    "lib/",
+    "classes/",
+    "functions/",
+    "internal/",
+    "ranges/",
+    "index.js",
+    "preload.js",
+    "range.bnf"
+  ],
+  "tap": {
+    "timeout": 30,
+    "coverage-map": "map.js",
+    "nyc-arg": [
+      "--exclude",
+      "tap-snapshots/**"
+    ]
+  },
+  "engines": {
+    "node": ">=10"
+  },
+  "author": "GitHub Inc.",
+  "templateOSS": {
+    "//@npmcli/template-oss": "This file is partially managed by @npmcli/template-oss. Edits may be overwritten.",
+    "version": "4.29.0",
+    "engines": ">=10",
+    "distPaths": [
+      "classes/",
+      "functions/",
+      "internal/",
+      "ranges/",
+      "index.js",
+      "preload.js",
+      "range.bnf"
+    ],
+    "allowPaths": [
+      "/classes/",
+      "/functions/",
+      "/internal/",
+      "/ranges/",
+      "/index.js",
+      "/preload.js",
+      "/range.bnf",
+      "/benchmarks"
+    ],
+    "publish": "true"
+  }
+}
diff --git a/server/node_modules/semver/preload.js b/server/node_modules/semver/preload.js
new file mode 100644
index 0000000..e6c47b9
--- /dev/null
+++ b/server/node_modules/semver/preload.js
@@ -0,0 +1,4 @@
+'use strict'
+
+// XXX remove in v8 or beyond
+module.exports = require('./index.js')
diff --git a/server/node_modules/semver/range.bnf b/server/node_modules/semver/range.bnf
new file mode 100644
index 0000000..d4c6ae0
--- /dev/null
+++ b/server/node_modules/semver/range.bnf
@@ -0,0 +1,16 @@
+range-set  ::= range ( logical-or range ) *
+logical-or ::= ( ' ' ) * '||' ( ' ' ) *
+range      ::= hyphen | simple ( ' ' simple ) * | ''
+hyphen     ::= partial ' - ' partial
+simple     ::= primitive | partial | tilde | caret
+primitive  ::= ( '<' | '>' | '>=' | '<=' | '=' ) partial
+partial    ::= xr ( '.' xr ( '.' xr qualifier ? )? )?
+xr         ::= 'x' | 'X' | '*' | nr
+nr         ::= '0' | [1-9] ( [0-9] ) *
+tilde      ::= '~' partial
+caret      ::= '^' partial
+qualifier  ::= ( '-' pre )? ( '+' build )?
+pre        ::= parts
+build      ::= parts
+parts      ::= part ( '.' part ) *
+part       ::= nr | [-0-9A-Za-z]+
diff --git a/server/node_modules/semver/ranges/gtr.js b/server/node_modules/semver/ranges/gtr.js
new file mode 100644
index 0000000..0e7601f
--- /dev/null
+++ b/server/node_modules/semver/ranges/gtr.js
@@ -0,0 +1,6 @@
+'use strict'
+
+// Determine if version is greater than all the versions possible in the range.
+const outside = require('./outside')
+const gtr = (version, range, options) => outside(version, range, '>', options)
+module.exports = gtr
diff --git a/server/node_modules/semver/ranges/intersects.js b/server/node_modules/semver/ranges/intersects.js
new file mode 100644
index 0000000..917be7e
--- /dev/null
+++ b/server/node_modules/semver/ranges/intersects.js
@@ -0,0 +1,9 @@
+'use strict'
+
+const Range = require('../classes/range')
+const intersects = (r1, r2, options) => {
+  r1 = new Range(r1, options)
+  r2 = new Range(r2, options)
+  return r1.intersects(r2, options)
+}
+module.exports = intersects
diff --git a/server/node_modules/semver/ranges/ltr.js b/server/node_modules/semver/ranges/ltr.js
new file mode 100644
index 0000000..aa5e568
--- /dev/null
+++ b/server/node_modules/semver/ranges/ltr.js
@@ -0,0 +1,6 @@
+'use strict'
+
+const outside = require('./outside')
+// Determine if version is less than all the versions possible in the range
+const ltr = (version, range, options) => outside(version, range, '<', options)
+module.exports = ltr
diff --git a/server/node_modules/semver/ranges/max-satisfying.js b/server/node_modules/semver/ranges/max-satisfying.js
new file mode 100644
index 0000000..01fe5ae
--- /dev/null
+++ b/server/node_modules/semver/ranges/max-satisfying.js
@@ -0,0 +1,27 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const Range = require('../classes/range')
+
+const maxSatisfying = (versions, range, options) => {
+  let max = null
+  let maxSV = null
+  let rangeObj = null
+  try {
+    rangeObj = new Range(range, options)
+  } catch (er) {
+    return null
+  }
+  versions.forEach((v) => {
+    if (rangeObj.test(v)) {
+      // satisfies(v, range, options)
+      if (!max || maxSV.compare(v) === -1) {
+        // compare(max, v, true)
+        max = v
+        maxSV = new SemVer(max, options)
+      }
+    }
+  })
+  return max
+}
+module.exports = maxSatisfying
diff --git a/server/node_modules/semver/ranges/min-satisfying.js b/server/node_modules/semver/ranges/min-satisfying.js
new file mode 100644
index 0000000..af89c8e
--- /dev/null
+++ b/server/node_modules/semver/ranges/min-satisfying.js
@@ -0,0 +1,26 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const Range = require('../classes/range')
+const minSatisfying = (versions, range, options) => {
+  let min = null
+  let minSV = null
+  let rangeObj = null
+  try {
+    rangeObj = new Range(range, options)
+  } catch (er) {
+    return null
+  }
+  versions.forEach((v) => {
+    if (rangeObj.test(v)) {
+      // satisfies(v, range, options)
+      if (!min || minSV.compare(v) === 1) {
+        // compare(min, v, true)
+        min = v
+        minSV = new SemVer(min, options)
+      }
+    }
+  })
+  return min
+}
+module.exports = minSatisfying
diff --git a/server/node_modules/semver/ranges/min-version.js b/server/node_modules/semver/ranges/min-version.js
new file mode 100644
index 0000000..09a65aa
--- /dev/null
+++ b/server/node_modules/semver/ranges/min-version.js
@@ -0,0 +1,63 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const Range = require('../classes/range')
+const gt = require('../functions/gt')
+
+const minVersion = (range, loose) => {
+  range = new Range(range, loose)
+
+  let minver = new SemVer('0.0.0')
+  if (range.test(minver)) {
+    return minver
+  }
+
+  minver = new SemVer('0.0.0-0')
+  if (range.test(minver)) {
+    return minver
+  }
+
+  minver = null
+  for (let i = 0; i < range.set.length; ++i) {
+    const comparators = range.set[i]
+
+    let setMin = null
+    comparators.forEach((comparator) => {
+      // Clone to avoid manipulating the comparator's semver object.
+      const compver = new SemVer(comparator.semver.version)
+      switch (comparator.operator) {
+        case '>':
+          if (compver.prerelease.length === 0) {
+            compver.patch++
+          } else {
+            compver.prerelease.push(0)
+          }
+          compver.raw = compver.format()
+          /* fallthrough */
+        case '':
+        case '>=':
+          if (!setMin || gt(compver, setMin)) {
+            setMin = compver
+          }
+          break
+        case '<':
+        case '<=':
+          /* Ignore maximum versions */
+          break
+        /* istanbul ignore next */
+        default:
+          throw new Error(`Unexpected operation: ${comparator.operator}`)
+      }
+    })
+    if (setMin && (!minver || gt(minver, setMin))) {
+      minver = setMin
+    }
+  }
+
+  if (minver && range.test(minver)) {
+    return minver
+  }
+
+  return null
+}
+module.exports = minVersion
diff --git a/server/node_modules/semver/ranges/outside.js b/server/node_modules/semver/ranges/outside.js
new file mode 100644
index 0000000..ca74421
--- /dev/null
+++ b/server/node_modules/semver/ranges/outside.js
@@ -0,0 +1,82 @@
+'use strict'
+
+const SemVer = require('../classes/semver')
+const Comparator = require('../classes/comparator')
+const { ANY } = Comparator
+const Range = require('../classes/range')
+const satisfies = require('../functions/satisfies')
+const gt = require('../functions/gt')
+const lt = require('../functions/lt')
+const lte = require('../functions/lte')
+const gte = require('../functions/gte')
+
+const outside = (version, range, hilo, options) => {
+  version = new SemVer(version, options)
+  range = new Range(range, options)
+
+  let gtfn, ltefn, ltfn, comp, ecomp
+  switch (hilo) {
+    case '>':
+      gtfn = gt
+      ltefn = lte
+      ltfn = lt
+      comp = '>'
+      ecomp = '>='
+      break
+    case '<':
+      gtfn = lt
+      ltefn = gte
+      ltfn = gt
+      comp = '<'
+      ecomp = '<='
+      break
+    default:
+      throw new TypeError('Must provide a hilo val of "<" or ">"')
+  }
+
+  // If it satisfies the range it is not outside
+  if (satisfies(version, range, options)) {
+    return false
+  }
+
+  // From now on, variable terms are as if we're in "gtr" mode.
+  // but note that everything is flipped for the "ltr" function.
+
+  for (let i = 0; i < range.set.length; ++i) {
+    const comparators = range.set[i]
+
+    let high = null
+    let low = null
+
+    comparators.forEach((comparator) => {
+      if (comparator.semver === ANY) {
+        comparator = new Comparator('>=0.0.0')
+      }
+      high = high || comparator
+      low = low || comparator
+      if (gtfn(comparator.semver, high.semver, options)) {
+        high = comparator
+      } else if (ltfn(comparator.semver, low.semver, options)) {
+        low = comparator
+      }
+    })
+
+    // If the edge version comparator has a operator then our version
+    // isn't outside it
+    if (high.operator === comp || high.operator === ecomp) {
+      return false
+    }
+
+    // If the lowest version comparator has an operator and our version
+    // is less than it then it isn't higher than the range
+    if ((!low.operator || low.operator === comp) &&
+        ltefn(version, low.semver)) {
+      return false
+    } else if (low.operator === ecomp && ltfn(version, low.semver)) {
+      return false
+    }
+  }
+  return true
+}
+
+module.exports = outside
diff --git a/server/node_modules/semver/ranges/simplify.js b/server/node_modules/semver/ranges/simplify.js
new file mode 100644
index 0000000..262732e
--- /dev/null
+++ b/server/node_modules/semver/ranges/simplify.js
@@ -0,0 +1,49 @@
+'use strict'
+
+// given a set of versions and a range, create a "simplified" range
+// that includes the same versions that the original range does
+// If the original range is shorter than the simplified one, return that.
+const satisfies = require('../functions/satisfies.js')
+const compare = require('../functions/compare.js')
+module.exports = (versions, range, options) => {
+  const set = []
+  let first = null
+  let prev = null
+  const v = versions.sort((a, b) => compare(a, b, options))
+  for (const version of v) {
+    const included = satisfies(version, range, options)
+    if (included) {
+      prev = version
+      if (!first) {
+        first = version
+      }
+    } else {
+      if (prev) {
+        set.push([first, prev])
+      }
+      prev = null
+      first = null
+    }
+  }
+  if (first) {
+    set.push([first, null])
+  }
+
+  const ranges = []
+  for (const [min, max] of set) {
+    if (min === max) {
+      ranges.push(min)
+    } else if (!max && min === v[0]) {
+      ranges.push('*')
+    } else if (!max) {
+      ranges.push(`>=${min}`)
+    } else if (min === v[0]) {
+      ranges.push(`<=${max}`)
+    } else {
+      ranges.push(`${min} - ${max}`)
+    }
+  }
+  const simplified = ranges.join(' || ')
+  const original = typeof range.raw === 'string' ? range.raw : String(range)
+  return simplified.length < original.length ? simplified : range
+}
diff --git a/server/node_modules/semver/ranges/subset.js b/server/node_modules/semver/ranges/subset.js
new file mode 100644
index 0000000..99f4321
--- /dev/null
+++ b/server/node_modules/semver/ranges/subset.js
@@ -0,0 +1,249 @@
+'use strict'
+
+const Range = require('../classes/range.js')
+const Comparator = require('../classes/comparator.js')
+const { ANY } = Comparator
+const satisfies = require('../functions/satisfies.js')
+const compare = require('../functions/compare.js')
+
+// Complex range `r1 || r2 || ...` is a subset of `R1 || R2 || ...` iff:
+// - Every simple range `r1, r2, ...` is a null set, OR
+// - Every simple range `r1, r2, ...` which is not a null set is a subset of
+//   some `R1, R2, ...`
+//
+// Simple range `c1 c2 ...` is a subset of simple range `C1 C2 ...` iff:
+// - If c is only the ANY comparator
+//   - If C is only the ANY comparator, return true
+//   - Else if in prerelease mode, return false
+//   - else replace c with `[>=0.0.0]`
+// - If C is only the ANY comparator
+//   - if in prerelease mode, return true
+//   - else replace C with `[>=0.0.0]`
+// - Let EQ be the set of = comparators in c
+// - If EQ is more than one, return true (null set)
+// - Let GT be the highest > or >= comparator in c
+// - Let LT be the lowest < or <= comparator in c
+// - If GT and LT, and GT.semver > LT.semver, return true (null set)
+// - If any C is a = range, and GT or LT are set, return false
+// - If EQ
+//   - If GT, and EQ does not satisfy GT, return true (null set)
+//   - If LT, and EQ does not satisfy LT, return true (null set)
+//   - If EQ satisfies every C, return true
+//   - Else return false
+// - If GT
+//   - If GT.semver is lower than any > or >= comp in C, return false
+//   - If GT is >=, and GT.semver does not satisfy every C, return false
+//   - If GT.semver has a prerelease, and not in prerelease mode
+//     - If no C has a prerelease and the GT.semver tuple, return false
+// - If LT
+//   - If LT.semver is greater than any < or <= comp in C, return false
+//   - If LT is <=, and LT.semver does not satisfy every C, return false
+//   - If LT.semver has a prerelease, and not in prerelease mode
+//     - If no C has a prerelease and the LT.semver tuple, return false
+// - Else return true
+
+const subset = (sub, dom, options = {}) => {
+  if (sub === dom) {
+    return true
+  }
+
+  sub = new Range(sub, options)
+  dom = new Range(dom, options)
+  let sawNonNull = false
+
+  OUTER: for (const simpleSub of sub.set) {
+    for (const simpleDom of dom.set) {
+      const isSub = simpleSubset(simpleSub, simpleDom, options)
+      sawNonNull = sawNonNull || isSub !== null
+      if (isSub) {
+        continue OUTER
+      }
+    }
+    // the null set is a subset of everything, but null simple ranges in
+    // a complex range should be ignored.  so if we saw a non-null range,
+    // then we know this isn't a subset, but if EVERY simple range was null,
+    // then it is a subset.
+    if (sawNonNull) {
+      return false
+    }
+  }
+  return true
+}
+
+const minimumVersionWithPreRelease = [new Comparator('>=0.0.0-0')]
+const minimumVersion = [new Comparator('>=0.0.0')]
+
+const simpleSubset = (sub, dom, options) => {
+  if (sub === dom) {
+    return true
+  }
+
+  if (sub.length === 1 && sub[0].semver === ANY) {
+    if (dom.length === 1 && dom[0].semver === ANY) {
+      return true
+    } else if (options.includePrerelease) {
+      sub = minimumVersionWithPreRelease
+    } else {
+      sub = minimumVersion
+    }
+  }
+
+  if (dom.length === 1 && dom[0].semver === ANY) {
+    if (options.includePrerelease) {
+      return true
+    } else {
+      dom = minimumVersion
+    }
+  }
+
+  const eqSet = new Set()
+  let gt, lt
+  for (const c of sub) {
+    if (c.operator === '>' || c.operator === '>=') {
+      gt = higherGT(gt, c, options)
+    } else if (c.operator === '<' || c.operator === '<=') {
+      lt = lowerLT(lt, c, options)
+    } else {
+      eqSet.add(c.semver)
+    }
+  }
+
+  if (eqSet.size > 1) {
+    return null
+  }
+
+  let gtltComp
+  if (gt && lt) {
+    gtltComp = compare(gt.semver, lt.semver, options)
+    if (gtltComp > 0) {
+      return null
+    } else if (gtltComp === 0 && (gt.operator !== '>=' || lt.operator !== '<=')) {
+      return null
+    }
+  }
+
+  // will iterate one or zero times
+  for (const eq of eqSet) {
+    if (gt && !satisfies(eq, String(gt), options)) {
+      return null
+    }
+
+    if (lt && !satisfies(eq, String(lt), options)) {
+      return null
+    }
+
+    for (const c of dom) {
+      if (!satisfies(eq, String(c), options)) {
+        return false
+      }
+    }
+
+    return true
+  }
+
+  let higher, lower
+  let hasDomLT, hasDomGT
+  // if the subset has a prerelease, we need a comparator in the superset
+  // with the same tuple and a prerelease, or it's not a subset
+  let needDomLTPre = lt &&
+    !options.includePrerelease &&
+    lt.semver.prerelease.length ? lt.semver : false
+  let needDomGTPre = gt &&
+    !options.includePrerelease &&
+    gt.semver.prerelease.length ? gt.semver : false
+  // exception: <1.2.3-0 is the same as <1.2.3
+  if (needDomLTPre && needDomLTPre.prerelease.length === 1 &&
+      lt.operator === '<' && needDomLTPre.prerelease[0] === 0) {
+    needDomLTPre = false
+  }
+
+  for (const c of dom) {
+    hasDomGT = hasDomGT || c.operator === '>' || c.operator === '>='
+    hasDomLT = hasDomLT || c.operator === '<' || c.operator === '<='
+    if (gt) {
+      if (needDomGTPre) {
+        if (c.semver.prerelease && c.semver.prerelease.length &&
+            c.semver.major === needDomGTPre.major &&
+            c.semver.minor === needDomGTPre.minor &&
+            c.semver.patch === needDomGTPre.patch) {
+          needDomGTPre = false
+        }
+      }
+      if (c.operator === '>' || c.operator === '>=') {
+        higher = higherGT(gt, c, options)
+        if (higher === c && higher !== gt) {
+          return false
+        }
+      } else if (gt.operator === '>=' && !satisfies(gt.semver, String(c), options)) {
+        return false
+      }
+    }
+    if (lt) {
+      if (needDomLTPre) {
+        if (c.semver.prerelease && c.semver.prerelease.length &&
+            c.semver.major === needDomLTPre.major &&
+            c.semver.minor === needDomLTPre.minor &&
+            c.semver.patch === needDomLTPre.patch) {
+          needDomLTPre = false
+        }
+      }
+      if (c.operator === '<' || c.operator === '<=') {
+        lower = lowerLT(lt, c, options)
+        if (lower === c && lower !== lt) {
+          return false
+        }
+      } else if (lt.operator === '<=' && !satisfies(lt.semver, String(c), options)) {
+        return false
+      }
+    }
+    if (!c.operator && (lt || gt) && gtltComp !== 0) {
+      return false
+    }
+  }
+
+  // if there was a < or >, and nothing in the dom, then must be false
+  // UNLESS it was limited by another range in the other direction.
+  // Eg, >1.0.0 <1.0.1 is still a subset of <2.0.0
+  if (gt && hasDomLT && !lt && gtltComp !== 0) {
+    return false
+  }
+
+  if (lt && hasDomGT && !gt && gtltComp !== 0) {
+    return false
+  }
+
+  // we needed a prerelease range in a specific tuple, but didn't get one
+  // then this isn't a subset.  eg >=1.2.3-pre is not a subset of >=1.0.0,
+  // because it includes prereleases in the 1.2.3 tuple
+  if (needDomGTPre || needDomLTPre) {
+    return false
+  }
+
+  return true
+}
+
+// >=1.2.3 is lower than >1.2.3
+const higherGT = (a, b, options) => {
+  if (!a) {
+    return b
+  }
+  const comp = compare(a.semver, b.semver, options)
+  return comp > 0 ? a
+    : comp < 0 ? b
+    : b.operator === '>' && a.operator === '>=' ? b
+    : a
+}
+
+// <=1.2.3 is higher than <1.2.3
+const lowerLT = (a, b, options) => {
+  if (!a) {
+    return b
+  }
+  const comp = compare(a.semver, b.semver, options)
+  return comp < 0 ? a
+    : comp > 0 ? b
+    : b.operator === '<' && a.operator === '<=' ? b
+    : a
+}
+
+module.exports = subset
diff --git a/server/node_modules/semver/ranges/to-comparators.js b/server/node_modules/semver/ranges/to-comparators.js
new file mode 100644
index 0000000..5be2519
--- /dev/null
+++ b/server/node_modules/semver/ranges/to-comparators.js
@@ -0,0 +1,10 @@
+'use strict'
+
+const Range = require('../classes/range')
+
+// Mostly just for testing and legacy API reasons
+const toComparators = (range, options) =>
+  new Range(range, options).set
+    .map(comp => comp.map(c => c.value).join(' ').trim().split(' '))
+
+module.exports = toComparators
diff --git a/server/node_modules/semver/ranges/valid.js b/server/node_modules/semver/ranges/valid.js
new file mode 100644
index 0000000..cc6b0e9
--- /dev/null
+++ b/server/node_modules/semver/ranges/valid.js
@@ -0,0 +1,13 @@
+'use strict'
+
+const Range = require('../classes/range')
+const validRange = (range, options) => {
+  try {
+    // Return '*' instead of '' so that truthiness works.
+    // This will throw if it's invalid anyway
+    return new Range(range, options).range || '*'
+  } catch (er) {
+    return null
+  }
+}
+module.exports = validRange
diff --git a/server/node_modules/send/HISTORY.md b/server/node_modules/send/HISTORY.md
new file mode 100644
index 0000000..13789ba
--- /dev/null
+++ b/server/node_modules/send/HISTORY.md
@@ -0,0 +1,538 @@
+0.19.2 / 2025-12-15
+===================
+
+* deps: use tilde notation for dependencies
+* deps: http-errors@~2.0.1
+* deps: statuses@~2.0.2
+
+0.19.1 / 2024-10-09
+===================
+
+* deps: encodeurl@~2.0.0
+
+0.19.0 / 2024-09-10
+===================
+
+* Remove link renderization in html while redirecting
+
+0.18.0 / 2022-03-23
+===================
+
+  * Fix emitted 416 error missing headers property
+  * Limit the headers removed for 304 response
+  * deps: depd@2.0.0
+    - Replace internal `eval` usage with `Function` constructor
+    - Use instance methods on `process` to check for listeners
+  * deps: destroy@1.2.0
+  * deps: http-errors@2.0.0
+    - deps: depd@2.0.0
+    - deps: statuses@2.0.1
+  * deps: on-finished@2.4.1
+  * deps: statuses@2.0.1
+
+0.17.2 / 2021-12-11
+===================
+
+  * pref: ignore empty http tokens
+  * deps: http-errors@1.8.1
+    - deps: inherits@2.0.4
+    - deps: toidentifier@1.0.1
+    - deps: setprototypeof@1.2.0
+  * deps: ms@2.1.3
+
+0.17.1 / 2019-05-10
+===================
+
+  * Set stricter CSP header in redirect & error responses
+  * deps: range-parser@~1.2.1
+
+0.17.0 / 2019-05-03
+===================
+
+  * deps: http-errors@~1.7.2
+    - Set constructor name when possible
+    - Use `toidentifier` module to make class names
+    - deps: depd@~1.1.2
+    - deps: setprototypeof@1.1.1
+    - deps: statuses@'>= 1.5.0 < 2'
+  * deps: mime@1.6.0
+    - Add extensions for JPEG-2000 images
+    - Add new `font/*` types from IANA
+    - Add WASM mapping
+    - Update `.bdoc` to `application/bdoc`
+    - Update `.bmp` to `image/bmp`
+    - Update `.m4a` to `audio/mp4`
+    - Update `.rtf` to `application/rtf`
+    - Update `.wav` to `audio/wav`
+    - Update `.xml` to `application/xml`
+    - Update generic extensions to `application/octet-stream`:
+      `.deb`, `.dll`, `.dmg`, `.exe`, `.iso`, `.msi`
+    - Use mime-score module to resolve extension conflicts
+  * deps: ms@2.1.1
+    - Add `week`/`w` support
+    - Fix negative number handling
+  * deps: statuses@~1.5.0
+  * perf: remove redundant `path.normalize` call
+
+0.16.2 / 2018-02-07
+===================
+
+  * Fix incorrect end tag in default error & redirects
+  * deps: depd@~1.1.2
+    - perf: remove argument reassignment
+  * deps: encodeurl@~1.0.2
+    - Fix encoding `%` as last character
+  * deps: statuses@~1.4.0
+
+0.16.1 / 2017-09-29
+===================
+
+  * Fix regression in edge-case behavior for empty `path`
+
+0.16.0 / 2017-09-27
+===================
+
+  * Add `immutable` option
+  * Fix missing `</html>` in default error & redirects
+  * Use instance methods on steam to check for listeners
+  * deps: mime@1.4.1
+    - Add 70 new types for file extensions
+    - Set charset as "UTF-8" for .js and .json
+  * perf: improve path validation speed
+
+0.15.6 / 2017-09-22
+===================
+
+  * deps: debug@2.6.9
+  * perf: improve `If-Match` token parsing
+
+0.15.5 / 2017-09-20
+===================
+
+  * deps: etag@~1.8.1
+    - perf: replace regular expression with substring
+  * deps: fresh@0.5.2
+    - Fix handling of modified headers with invalid dates
+    - perf: improve ETag match loop
+    - perf: improve `If-None-Match` token parsing
+
+0.15.4 / 2017-08-05
+===================
+
+  * deps: debug@2.6.8
+  * deps: depd@~1.1.1
+    - Remove unnecessary `Buffer` loading
+  * deps: http-errors@~1.6.2
+    - deps: depd@1.1.1
+
+0.15.3 / 2017-05-16
+===================
+
+  * deps: debug@2.6.7
+    - deps: ms@2.0.0
+  * deps: ms@2.0.0
+
+0.15.2 / 2017-04-26
+===================
+
+  * deps: debug@2.6.4
+    - Fix `DEBUG_MAX_ARRAY_LENGTH`
+    - deps: ms@0.7.3
+  * deps: ms@1.0.0
+
+0.15.1 / 2017-03-04
+===================
+
+  * Fix issue when `Date.parse` does not return `NaN` on invalid date
+  * Fix strict violation in broken environments
+
+0.15.0 / 2017-02-25
+===================
+
+  * Support `If-Match` and `If-Unmodified-Since` headers
+  * Add `res` and `path` arguments to `directory` event
+  * Remove usage of `res._headers` private field
+    - Improves compatibility with Node.js 8 nightly
+  * Send complete HTML document in redirect & error responses
+  * Set default CSP header in redirect & error responses
+  * Use `res.getHeaderNames()` when available
+  * Use `res.headersSent` when available
+  * deps: debug@2.6.1
+    - Allow colors in workers
+    - Deprecated `DEBUG_FD` environment variable set to `3` or higher
+    - Fix error when running under React Native
+    - Use same color for same namespace
+    - deps: ms@0.7.2
+  * deps: etag@~1.8.0
+  * deps: fresh@0.5.0
+    - Fix false detection of `no-cache` request directive
+    - Fix incorrect result when `If-None-Match` has both `*` and ETags
+    - Fix weak `ETag` matching to match spec
+    - perf: delay reading header values until needed
+    - perf: enable strict mode
+    - perf: hoist regular expressions
+    - perf: remove duplicate conditional
+    - perf: remove unnecessary boolean coercions
+    - perf: skip checking modified time if ETag check failed
+    - perf: skip parsing `If-None-Match` when no `ETag` header
+    - perf: use `Date.parse` instead of `new Date`
+  * deps: http-errors@~1.6.1
+    - Make `message` property enumerable for `HttpError`s
+    - deps: setprototypeof@1.0.3
+
+0.14.2 / 2017-01-23
+===================
+
+  * deps: http-errors@~1.5.1
+    - deps: inherits@2.0.3
+    - deps: setprototypeof@1.0.2
+    - deps: statuses@'>= 1.3.1 < 2'
+  * deps: ms@0.7.2
+  * deps: statuses@~1.3.1
+
+0.14.1 / 2016-06-09
+===================
+
+  * Fix redirect error when `path` contains raw non-URL characters
+  * Fix redirect when `path` starts with multiple forward slashes
+
+0.14.0 / 2016-06-06
+===================
+
+  * Add `acceptRanges` option
+  * Add `cacheControl` option
+  * Attempt to combine multiple ranges into single range
+  * Correctly inherit from `Stream` class
+  * Fix `Content-Range` header in 416 responses when using `start`/`end` options
+  * Fix `Content-Range` header missing from default 416 responses
+  * Ignore non-byte `Range` headers
+  * deps: http-errors@~1.5.0
+    - Add `HttpError` export, for `err instanceof createError.HttpError`
+    - Support new code `421 Misdirected Request`
+    - Use `setprototypeof` module to replace `__proto__` setting
+    - deps: inherits@2.0.1
+    - deps: statuses@'>= 1.3.0 < 2'
+    - perf: enable strict mode
+  * deps: range-parser@~1.2.0
+    - Fix incorrectly returning -1 when there is at least one valid range
+    - perf: remove internal function
+  * deps: statuses@~1.3.0
+    - Add `421 Misdirected Request`
+    - perf: enable strict mode
+  * perf: remove argument reassignment
+
+0.13.2 / 2016-03-05
+===================
+
+  * Fix invalid `Content-Type` header when `send.mime.default_type` unset
+
+0.13.1 / 2016-01-16
+===================
+
+  * deps: depd@~1.1.0
+    - Support web browser loading
+    - perf: enable strict mode
+  * deps: destroy@~1.0.4
+    - perf: enable strict mode
+  * deps: escape-html@~1.0.3
+    - perf: enable strict mode
+    - perf: optimize string replacement
+    - perf: use faster string coercion
+  * deps: range-parser@~1.0.3
+    - perf: enable strict mode
+
+0.13.0 / 2015-06-16
+===================
+
+  * Allow Node.js HTTP server to set `Date` response header
+  * Fix incorrectly removing `Content-Location` on 304 response
+  * Improve the default redirect response headers
+  * Send appropriate headers on default error response
+  * Use `http-errors` for standard emitted errors
+  * Use `statuses` instead of `http` module for status messages
+  * deps: escape-html@1.0.2
+  * deps: etag@~1.7.0
+    - Improve stat performance by removing hashing
+  * deps: fresh@0.3.0
+    - Add weak `ETag` matching support
+  * deps: on-finished@~2.3.0
+    - Add defined behavior for HTTP `CONNECT` requests
+    - Add defined behavior for HTTP `Upgrade` requests
+    - deps: ee-first@1.1.1
+  * perf: enable strict mode
+  * perf: remove unnecessary array allocations
+
+0.12.3 / 2015-05-13
+===================
+
+  * deps: debug@~2.2.0
+    - deps: ms@0.7.1
+  * deps: depd@~1.0.1
+  * deps: etag@~1.6.0
+   - Improve support for JXcore
+   - Support "fake" stats objects in environments without `fs`
+  * deps: ms@0.7.1
+    - Prevent extraordinarily long inputs
+  * deps: on-finished@~2.2.1
+
+0.12.2 / 2015-03-13
+===================
+
+  * Throw errors early for invalid `extensions` or `index` options
+  * deps: debug@~2.1.3
+    - Fix high intensity foreground color for bold
+    - deps: ms@0.7.0
+
+0.12.1 / 2015-02-17
+===================
+
+  * Fix regression sending zero-length files
+
+0.12.0 / 2015-02-16
+===================
+
+  * Always read the stat size from the file
+  * Fix mutating passed-in `options`
+  * deps: mime@1.3.4
+
+0.11.1 / 2015-01-20
+===================
+
+  * Fix `root` path disclosure
+
+0.11.0 / 2015-01-05
+===================
+
+  * deps: debug@~2.1.1
+  * deps: etag@~1.5.1
+    - deps: crc@3.2.1
+  * deps: ms@0.7.0
+    - Add `milliseconds`
+    - Add `msecs`
+    - Add `secs`
+    - Add `mins`
+    - Add `hrs`
+    - Add `yrs`
+  * deps: on-finished@~2.2.0
+
+0.10.1 / 2014-10-22
+===================
+
+  * deps: on-finished@~2.1.1
+    - Fix handling of pipelined requests
+
+0.10.0 / 2014-10-15
+===================
+
+  * deps: debug@~2.1.0
+    - Implement `DEBUG_FD` env variable support
+  * deps: depd@~1.0.0
+  * deps: etag@~1.5.0
+    - Improve string performance
+    - Slightly improve speed for weak ETags over 1KB
+
+0.9.3 / 2014-09-24
+==================
+
+  * deps: etag@~1.4.0
+    - Support "fake" stats objects
+
+0.9.2 / 2014-09-15
+==================
+
+  * deps: depd@0.4.5
+  * deps: etag@~1.3.1
+  * deps: range-parser@~1.0.2
+
+0.9.1 / 2014-09-07
+==================
+
+  * deps: fresh@0.2.4
+
+0.9.0 / 2014-09-07
+==================
+
+  * Add `lastModified` option
+  * Use `etag` to generate `ETag` header
+  * deps: debug@~2.0.0
+
+0.8.5 / 2014-09-04
+==================
+
+  * Fix malicious path detection for empty string path
+
+0.8.4 / 2014-09-04
+==================
+
+  * Fix a path traversal issue when using `root`
+
+0.8.3 / 2014-08-16
+==================
+
+  * deps: destroy@1.0.3
+    - renamed from dethroy
+  * deps: on-finished@2.1.0
+
+0.8.2 / 2014-08-14
+==================
+
+  * Work around `fd` leak in Node.js 0.10 for `fs.ReadStream`
+  * deps: dethroy@1.0.2
+
+0.8.1 / 2014-08-05
+==================
+
+  * Fix `extensions` behavior when file already has extension
+
+0.8.0 / 2014-08-05
+==================
+
+  * Add `extensions` option
+
+0.7.4 / 2014-08-04
+==================
+
+  * Fix serving index files without root dir
+
+0.7.3 / 2014-07-29
+==================
+
+  * Fix incorrect 403 on Windows and Node.js 0.11
+
+0.7.2 / 2014-07-27
+==================
+
+  * deps: depd@0.4.4
+    - Work-around v8 generating empty stack traces
+
+0.7.1 / 2014-07-26
+==================
+
+ * deps: depd@0.4.3
+   - Fix exception when global `Error.stackTraceLimit` is too low
+
+0.7.0 / 2014-07-20
+==================
+
+ * Deprecate `hidden` option; use `dotfiles` option
+ * Add `dotfiles` option
+ * deps: debug@1.0.4
+ * deps: depd@0.4.2
+   - Add `TRACE_DEPRECATION` environment variable
+   - Remove non-standard grey color from color output
+   - Support `--no-deprecation` argument
+   - Support `--trace-deprecation` argument
+
+0.6.0 / 2014-07-11
+==================
+
+ * Deprecate `from` option; use `root` option
+ * Deprecate `send.etag()` -- use `etag` in `options`
+ * Deprecate `send.hidden()` -- use `hidden` in `options`
+ * Deprecate `send.index()` -- use `index` in `options`
+ * Deprecate `send.maxage()` -- use `maxAge` in `options`
+ * Deprecate `send.root()` -- use `root` in `options`
+ * Cap `maxAge` value to 1 year
+ * deps: debug@1.0.3
+   - Add support for multiple wildcards in namespaces
+
+0.5.0 / 2014-06-28
+==================
+
+ * Accept string for `maxAge` (converted by `ms`)
+ * Add `headers` event
+ * Include link in default redirect response
+ * Use `EventEmitter.listenerCount` to count listeners
+
+0.4.3 / 2014-06-11
+==================
+
+ * Do not throw un-catchable error on file open race condition
+ * Use `escape-html` for HTML escaping
+ * deps: debug@1.0.2
+   - fix some debugging output colors on node.js 0.8
+ * deps: finished@1.2.2
+ * deps: fresh@0.2.2
+
+0.4.2 / 2014-06-09
+==================
+
+ * fix "event emitter leak" warnings
+ * deps: debug@1.0.1
+ * deps: finished@1.2.1
+
+0.4.1 / 2014-06-02
+==================
+
+ * Send `max-age` in `Cache-Control` in correct format
+
+0.4.0 / 2014-05-27
+==================
+
+ * Calculate ETag with md5 for reduced collisions
+ * Fix wrong behavior when index file matches directory
+ * Ignore stream errors after request ends
+   - Goodbye `EBADF, read`
+ * Skip directories in index file search
+ * deps: debug@0.8.1
+
+0.3.0 / 2014-04-24
+==================
+
+ * Fix sending files with dots without root set
+ * Coerce option types
+ * Accept API options in options object
+ * Set etags to "weak"
+ * Include file path in etag
+ * Make "Can't set headers after they are sent." catchable
+ * Send full entity-body for multi range requests
+ * Default directory access to 403 when index disabled
+ * Support multiple index paths
+ * Support "If-Range" header
+ * Control whether to generate etags
+ * deps: mime@1.2.11
+
+0.2.0 / 2014-01-29
+==================
+
+ * update range-parser and fresh
+
+0.1.4 / 2013-08-11
+==================
+
+ * update fresh
+
+0.1.3 / 2013-07-08
+==================
+
+ * Revert "Fix fd leak"
+
+0.1.2 / 2013-07-03
+==================
+
+ * Fix fd leak
+
+0.1.0 / 2012-08-25
+==================
+
+  * add options parameter to send() that is passed to fs.createReadStream() [kanongil]
+
+0.0.4 / 2012-08-16
+==================
+
+  * allow custom "Accept-Ranges" definition
+
+0.0.3 / 2012-07-16
+==================
+
+  * fix normalization of the root directory. Closes #3
+
+0.0.2 / 2012-07-09
+==================
+
+  * add passing of req explicitly for now (YUCK)
+
+0.0.1 / 2010-01-03
+==================
+
+  * Initial release
diff --git a/server/node_modules/send/LICENSE b/server/node_modules/send/LICENSE
new file mode 100644
index 0000000..b6ea1c1
--- /dev/null
+++ b/server/node_modules/send/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2012 TJ Holowaychuk
+Copyright (c) 2014-2022 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/send/README.md b/server/node_modules/send/README.md
new file mode 100644
index 0000000..fadf838
--- /dev/null
+++ b/server/node_modules/send/README.md
@@ -0,0 +1,327 @@
+# send
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Linux Build][github-actions-ci-image]][github-actions-ci-url]
+[![Windows Build][appveyor-image]][appveyor-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Send is a library for streaming files from the file system as a http response
+supporting partial responses (Ranges), conditional-GET negotiation (If-Match,
+If-Unmodified-Since, If-None-Match, If-Modified-Since), high test coverage,
+and granular events which may be leveraged to take appropriate actions in your
+application or framework.
+
+Looking to serve up entire folders mapped to URLs? Try [serve-static](https://www.npmjs.org/package/serve-static).
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```bash
+$ npm install send
+```
+
+## API
+
+```js
+var send = require('send')
+```
+
+### send(req, path, [options])
+
+Create a new `SendStream` for the given path to send to a `res`. The `req` is
+the Node.js HTTP request and the `path` is a urlencoded path to send (urlencoded,
+not the actual file-system path).
+
+#### Options
+
+##### acceptRanges
+
+Enable or disable accepting ranged requests, defaults to true.
+Disabling this will not send `Accept-Ranges` and ignore the contents
+of the `Range` request header.
+
+##### cacheControl
+
+Enable or disable setting `Cache-Control` response header, defaults to
+true. Disabling this will ignore the `immutable` and `maxAge` options.
+
+##### dotfiles
+
+Set how "dotfiles" are treated when encountered. A dotfile is a file
+or directory that begins with a dot ("."). Note this check is done on
+the path itself without checking if the path actually exists on the
+disk. If `root` is specified, only the dotfiles above the root are
+checked (i.e. the root itself can be within a dotfile when when set
+to "deny").
+
+  - `'allow'` No special treatment for dotfiles.
+  - `'deny'` Send a 403 for any request for a dotfile.
+  - `'ignore'` Pretend like the dotfile does not exist and 404.
+
+The default value is _similar_ to `'ignore'`, with the exception that
+this default will not ignore the files within a directory that begins
+with a dot, for backward-compatibility.
+
+##### end
+
+Byte offset at which the stream ends, defaults to the length of the file
+minus 1. The end is inclusive in the stream, meaning `end: 3` will include
+the 4th byte in the stream.
+
+##### etag
+
+Enable or disable etag generation, defaults to true.
+
+##### extensions
+
+If a given file doesn't exist, try appending one of the given extensions,
+in the given order. By default, this is disabled (set to `false`). An
+example value that will serve extension-less HTML files: `['html', 'htm']`.
+This is skipped if the requested file already has an extension.
+
+##### immutable
+
+Enable or disable the `immutable` directive in the `Cache-Control` response
+header, defaults to `false`. If set to `true`, the `maxAge` option should
+also be specified to enable caching. The `immutable` directive will prevent
+supported clients from making conditional requests during the life of the
+`maxAge` option to check if the file has changed.
+
+##### index
+
+By default send supports "index.html" files, to disable this
+set `false` or to supply a new index pass a string or an array
+in preferred order.
+
+##### lastModified
+
+Enable or disable `Last-Modified` header, defaults to true. Uses the file
+system's last modified value.
+
+##### maxAge
+
+Provide a max-age in milliseconds for http caching, defaults to 0.
+This can also be a string accepted by the
+[ms](https://www.npmjs.org/package/ms#readme) module.
+
+##### root
+
+Serve files relative to `path`.
+
+##### start
+
+Byte offset at which the stream starts, defaults to 0. The start is inclusive,
+meaning `start: 2` will include the 3rd byte in the stream.
+
+#### Events
+
+The `SendStream` is an event emitter and will emit the following events:
+
+  - `error` an error occurred `(err)`
+  - `directory` a directory was requested `(res, path)`
+  - `file` a file was requested `(path, stat)`
+  - `headers` the headers are about to be set on a file `(res, path, stat)`
+  - `stream` file streaming has started `(stream)`
+  - `end` streaming has completed
+
+#### .pipe
+
+The `pipe` method is used to pipe the response into the Node.js HTTP response
+object, typically `send(req, path, options).pipe(res)`.
+
+### .mime
+
+The `mime` export is the global instance of of the
+[`mime` npm module](https://www.npmjs.com/package/mime).
+
+This is used to configure the MIME types that are associated with file extensions
+as well as other options for how to resolve the MIME type of a file (like the
+default type to use for an unknown file extension).
+
+## Error-handling
+
+By default when no `error` listeners are present an automatic response will be
+made, otherwise you have full control over the response, aka you may show a 5xx
+page etc.
+
+## Caching
+
+It does _not_ perform internal caching, you should use a reverse proxy cache
+such as Varnish for this, or those fancy things called CDNs. If your
+application is small enough that it would benefit from single-node memory
+caching, it's small enough that it does not need caching at all ;).
+
+## Debugging
+
+To enable `debug()` instrumentation output export __DEBUG__:
+
+```
+$ DEBUG=send node app
+```
+
+## Running tests
+
+```
+$ npm install
+$ npm test
+```
+
+## Examples
+
+### Serve a specific file
+
+This simple example will send a specific file to all requests.
+
+```js
+var http = require('http')
+var send = require('send')
+
+var server = http.createServer(function onRequest (req, res) {
+  send(req, '/path/to/index.html')
+    .pipe(res)
+})
+
+server.listen(3000)
+```
+
+### Serve all files from a directory
+
+This simple example will just serve up all the files in a
+given directory as the top-level. For example, a request
+`GET /foo.txt` will send back `/www/public/foo.txt`.
+
+```js
+var http = require('http')
+var parseUrl = require('parseurl')
+var send = require('send')
+
+var server = http.createServer(function onRequest (req, res) {
+  send(req, parseUrl(req).pathname, { root: '/www/public' })
+    .pipe(res)
+})
+
+server.listen(3000)
+```
+
+### Custom file types
+
+```js
+var http = require('http')
+var parseUrl = require('parseurl')
+var send = require('send')
+
+// Default unknown types to text/plain
+send.mime.default_type = 'text/plain'
+
+// Add a custom type
+send.mime.define({
+  'application/x-my-type': ['x-mt', 'x-mtt']
+})
+
+var server = http.createServer(function onRequest (req, res) {
+  send(req, parseUrl(req).pathname, { root: '/www/public' })
+    .pipe(res)
+})
+
+server.listen(3000)
+```
+
+### Custom directory index view
+
+This is a example of serving up a structure of directories with a
+custom function to render a listing of a directory.
+
+```js
+var http = require('http')
+var fs = require('fs')
+var parseUrl = require('parseurl')
+var send = require('send')
+
+// Transfer arbitrary files from within /www/example.com/public/*
+// with a custom handler for directory listing
+var server = http.createServer(function onRequest (req, res) {
+  send(req, parseUrl(req).pathname, { index: false, root: '/www/public' })
+    .once('directory', directory)
+    .pipe(res)
+})
+
+server.listen(3000)
+
+// Custom directory handler
+function directory (res, path) {
+  var stream = this
+
+  // redirect to trailing slash for consistent url
+  if (!stream.hasTrailingSlash()) {
+    return stream.redirect(path)
+  }
+
+  // get directory list
+  fs.readdir(path, function onReaddir (err, list) {
+    if (err) return stream.error(err)
+
+    // render an index for the directory
+    res.setHeader('Content-Type', 'text/plain; charset=UTF-8')
+    res.end(list.join('\n') + '\n')
+  })
+}
+```
+
+### Serving from a root directory with custom error-handling
+
+```js
+var http = require('http')
+var parseUrl = require('parseurl')
+var send = require('send')
+
+var server = http.createServer(function onRequest (req, res) {
+  // your custom error-handling logic:
+  function error (err) {
+    res.statusCode = err.status || 500
+    res.end(err.message)
+  }
+
+  // your custom headers
+  function headers (res, path, stat) {
+    // serve all files for download
+    res.setHeader('Content-Disposition', 'attachment')
+  }
+
+  // your custom directory handling logic:
+  function redirect () {
+    res.statusCode = 301
+    res.setHeader('Location', req.url + '/')
+    res.end('Redirecting to ' + req.url + '/')
+  }
+
+  // transfer arbitrary files from within
+  // /www/example.com/public/*
+  send(req, parseUrl(req).pathname, { root: '/www/public' })
+    .on('error', error)
+    .on('directory', redirect)
+    .on('headers', headers)
+    .pipe(res)
+})
+
+server.listen(3000)
+```
+
+## License
+
+[MIT](LICENSE)
+
+[appveyor-image]: https://badgen.net/appveyor/ci/dougwilson/send/master?label=windows
+[appveyor-url]: https://ci.appveyor.com/project/dougwilson/send
+[coveralls-image]: https://badgen.net/coveralls/c/github/pillarjs/send/master
+[coveralls-url]: https://coveralls.io/r/pillarjs/send?branch=master
+[github-actions-ci-image]: https://badgen.net/github/checks/pillarjs/send/master?label=linux
+[github-actions-ci-url]: https://github.com/pillarjs/send/actions/workflows/ci.yml
+[node-image]: https://badgen.net/npm/node/send
+[node-url]: https://nodejs.org/en/download/
+[npm-downloads-image]: https://badgen.net/npm/dm/send
+[npm-url]: https://npmjs.org/package/send
+[npm-version-image]: https://badgen.net/npm/v/send
diff --git a/server/node_modules/send/SECURITY.md b/server/node_modules/send/SECURITY.md
new file mode 100644
index 0000000..46b48f7
--- /dev/null
+++ b/server/node_modules/send/SECURITY.md
@@ -0,0 +1,24 @@
+# Security Policies and Procedures
+
+## Reporting a Bug
+
+The `send` team and community take all security bugs seriously. Thank you
+for improving the security of Express. We appreciate your efforts and
+responsible disclosure and will make every effort to acknowledge your
+contributions.
+
+Report security bugs by emailing the current owner(s) of `send`. This information
+can be found in the npm registry using the command `npm owner ls send`.
+If unsure or unable to get the information from the above, open an issue
+in the [project issue tracker](https://github.com/pillarjs/send/issues)
+asking for the current contact information.
+
+To ensure the timely response to your report, please ensure that the entirety
+of the report is contained within the email body and not solely behind a web
+link or an attachment.
+
+At least one owner will acknowledge your email within 48 hours, and will send a
+more detailed response within 48 hours indicating the next steps in handling
+your report. After the initial reply to your report, the owners will
+endeavor to keep you informed of the progress towards a fix and full
+announcement, and may ask for additional information or guidance.
diff --git a/server/node_modules/send/index.js b/server/node_modules/send/index.js
new file mode 100644
index 0000000..768f8ca
--- /dev/null
+++ b/server/node_modules/send/index.js
@@ -0,0 +1,1142 @@
+/*!
+ * send
+ * Copyright(c) 2012 TJ Holowaychuk
+ * Copyright(c) 2014-2022 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var createError = require('http-errors')
+var debug = require('debug')('send')
+var deprecate = require('depd')('send')
+var destroy = require('destroy')
+var encodeUrl = require('encodeurl')
+var escapeHtml = require('escape-html')
+var etag = require('etag')
+var fresh = require('fresh')
+var fs = require('fs')
+var mime = require('mime')
+var ms = require('ms')
+var onFinished = require('on-finished')
+var parseRange = require('range-parser')
+var path = require('path')
+var statuses = require('statuses')
+var Stream = require('stream')
+var util = require('util')
+
+/**
+ * Path function references.
+ * @private
+ */
+
+var extname = path.extname
+var join = path.join
+var normalize = path.normalize
+var resolve = path.resolve
+var sep = path.sep
+
+/**
+ * Regular expression for identifying a bytes Range header.
+ * @private
+ */
+
+var BYTES_RANGE_REGEXP = /^ *bytes=/
+
+/**
+ * Maximum value allowed for the max age.
+ * @private
+ */
+
+var MAX_MAXAGE = 60 * 60 * 24 * 365 * 1000 // 1 year
+
+/**
+ * Regular expression to match a path with a directory up component.
+ * @private
+ */
+
+var UP_PATH_REGEXP = /(?:^|[\\/])\.\.(?:[\\/]|$)/
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = send
+module.exports.mime = mime
+
+/**
+ * Return a `SendStream` for `req` and `path`.
+ *
+ * @param {object} req
+ * @param {string} path
+ * @param {object} [options]
+ * @return {SendStream}
+ * @public
+ */
+
+function send (req, path, options) {
+  return new SendStream(req, path, options)
+}
+
+/**
+ * Initialize a `SendStream` with the given `path`.
+ *
+ * @param {Request} req
+ * @param {String} path
+ * @param {object} [options]
+ * @private
+ */
+
+function SendStream (req, path, options) {
+  Stream.call(this)
+
+  var opts = options || {}
+
+  this.options = opts
+  this.path = path
+  this.req = req
+
+  this._acceptRanges = opts.acceptRanges !== undefined
+    ? Boolean(opts.acceptRanges)
+    : true
+
+  this._cacheControl = opts.cacheControl !== undefined
+    ? Boolean(opts.cacheControl)
+    : true
+
+  this._etag = opts.etag !== undefined
+    ? Boolean(opts.etag)
+    : true
+
+  this._dotfiles = opts.dotfiles !== undefined
+    ? opts.dotfiles
+    : 'ignore'
+
+  if (this._dotfiles !== 'ignore' && this._dotfiles !== 'allow' && this._dotfiles !== 'deny') {
+    throw new TypeError('dotfiles option must be "allow", "deny", or "ignore"')
+  }
+
+  this._hidden = Boolean(opts.hidden)
+
+  if (opts.hidden !== undefined) {
+    deprecate('hidden: use dotfiles: \'' + (this._hidden ? 'allow' : 'ignore') + '\' instead')
+  }
+
+  // legacy support
+  if (opts.dotfiles === undefined) {
+    this._dotfiles = undefined
+  }
+
+  this._extensions = opts.extensions !== undefined
+    ? normalizeList(opts.extensions, 'extensions option')
+    : []
+
+  this._immutable = opts.immutable !== undefined
+    ? Boolean(opts.immutable)
+    : false
+
+  this._index = opts.index !== undefined
+    ? normalizeList(opts.index, 'index option')
+    : ['index.html']
+
+  this._lastModified = opts.lastModified !== undefined
+    ? Boolean(opts.lastModified)
+    : true
+
+  this._maxage = opts.maxAge || opts.maxage
+  this._maxage = typeof this._maxage === 'string'
+    ? ms(this._maxage)
+    : Number(this._maxage)
+  this._maxage = !isNaN(this._maxage)
+    ? Math.min(Math.max(0, this._maxage), MAX_MAXAGE)
+    : 0
+
+  this._root = opts.root
+    ? resolve(opts.root)
+    : null
+
+  if (!this._root && opts.from) {
+    this.from(opts.from)
+  }
+}
+
+/**
+ * Inherits from `Stream`.
+ */
+
+util.inherits(SendStream, Stream)
+
+/**
+ * Enable or disable etag generation.
+ *
+ * @param {Boolean} val
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.etag = deprecate.function(function etag (val) {
+  this._etag = Boolean(val)
+  debug('etag %s', this._etag)
+  return this
+}, 'send.etag: pass etag as option')
+
+/**
+ * Enable or disable "hidden" (dot) files.
+ *
+ * @param {Boolean} path
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.hidden = deprecate.function(function hidden (val) {
+  this._hidden = Boolean(val)
+  this._dotfiles = undefined
+  debug('hidden %s', this._hidden)
+  return this
+}, 'send.hidden: use dotfiles option')
+
+/**
+ * Set index `paths`, set to a falsy
+ * value to disable index support.
+ *
+ * @param {String|Boolean|Array} paths
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.index = deprecate.function(function index (paths) {
+  var index = !paths ? [] : normalizeList(paths, 'paths argument')
+  debug('index %o', paths)
+  this._index = index
+  return this
+}, 'send.index: pass index as option')
+
+/**
+ * Set root `path`.
+ *
+ * @param {String} path
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.root = function root (path) {
+  this._root = resolve(String(path))
+  debug('root %s', this._root)
+  return this
+}
+
+SendStream.prototype.from = deprecate.function(SendStream.prototype.root,
+  'send.from: pass root as option')
+
+SendStream.prototype.root = deprecate.function(SendStream.prototype.root,
+  'send.root: pass root as option')
+
+/**
+ * Set max-age to `maxAge`.
+ *
+ * @param {Number} maxAge
+ * @return {SendStream}
+ * @api public
+ */
+
+SendStream.prototype.maxage = deprecate.function(function maxage (maxAge) {
+  this._maxage = typeof maxAge === 'string'
+    ? ms(maxAge)
+    : Number(maxAge)
+  this._maxage = !isNaN(this._maxage)
+    ? Math.min(Math.max(0, this._maxage), MAX_MAXAGE)
+    : 0
+  debug('max-age %d', this._maxage)
+  return this
+}, 'send.maxage: pass maxAge as option')
+
+/**
+ * Emit error with `status`.
+ *
+ * @param {number} status
+ * @param {Error} [err]
+ * @private
+ */
+
+SendStream.prototype.error = function error (status, err) {
+  // emit if listeners instead of responding
+  if (hasListeners(this, 'error')) {
+    return this.emit('error', createHttpError(status, err))
+  }
+
+  var res = this.res
+  var msg = statuses.message[status] || String(status)
+  var doc = createHtmlDocument('Error', escapeHtml(msg))
+
+  // clear existing headers
+  clearHeaders(res)
+
+  // add error headers
+  if (err && err.headers) {
+    setHeaders(res, err.headers)
+  }
+
+  // send basic response
+  res.statusCode = status
+  res.setHeader('Content-Type', 'text/html; charset=UTF-8')
+  res.setHeader('Content-Length', Buffer.byteLength(doc))
+  res.setHeader('Content-Security-Policy', "default-src 'none'")
+  res.setHeader('X-Content-Type-Options', 'nosniff')
+  res.end(doc)
+}
+
+/**
+ * Check if the pathname ends with "/".
+ *
+ * @return {boolean}
+ * @private
+ */
+
+SendStream.prototype.hasTrailingSlash = function hasTrailingSlash () {
+  return this.path[this.path.length - 1] === '/'
+}
+
+/**
+ * Check if this is a conditional GET request.
+ *
+ * @return {Boolean}
+ * @api private
+ */
+
+SendStream.prototype.isConditionalGET = function isConditionalGET () {
+  return this.req.headers['if-match'] ||
+    this.req.headers['if-unmodified-since'] ||
+    this.req.headers['if-none-match'] ||
+    this.req.headers['if-modified-since']
+}
+
+/**
+ * Check if the request preconditions failed.
+ *
+ * @return {boolean}
+ * @private
+ */
+
+SendStream.prototype.isPreconditionFailure = function isPreconditionFailure () {
+  var req = this.req
+  var res = this.res
+
+  // if-match
+  var match = req.headers['if-match']
+  if (match) {
+    var etag = res.getHeader('ETag')
+    return !etag || (match !== '*' && parseTokenList(match).every(function (match) {
+      return match !== etag && match !== 'W/' + etag && 'W/' + match !== etag
+    }))
+  }
+
+  // if-unmodified-since
+  var unmodifiedSince = parseHttpDate(req.headers['if-unmodified-since'])
+  if (!isNaN(unmodifiedSince)) {
+    var lastModified = parseHttpDate(res.getHeader('Last-Modified'))
+    return isNaN(lastModified) || lastModified > unmodifiedSince
+  }
+
+  return false
+}
+
+/**
+ * Strip various content header fields for a change in entity.
+ *
+ * @private
+ */
+
+SendStream.prototype.removeContentHeaderFields = function removeContentHeaderFields () {
+  var res = this.res
+
+  res.removeHeader('Content-Encoding')
+  res.removeHeader('Content-Language')
+  res.removeHeader('Content-Length')
+  res.removeHeader('Content-Range')
+  res.removeHeader('Content-Type')
+}
+
+/**
+ * Respond with 304 not modified.
+ *
+ * @api private
+ */
+
+SendStream.prototype.notModified = function notModified () {
+  var res = this.res
+  debug('not modified')
+  this.removeContentHeaderFields()
+  res.statusCode = 304
+  res.end()
+}
+
+/**
+ * Raise error that headers already sent.
+ *
+ * @api private
+ */
+
+SendStream.prototype.headersAlreadySent = function headersAlreadySent () {
+  var err = new Error('Can\'t set headers after they are sent.')
+  debug('headers already sent')
+  this.error(500, err)
+}
+
+/**
+ * Check if the request is cacheable, aka
+ * responded with 2xx or 304 (see RFC 2616 section 14.2{5,6}).
+ *
+ * @return {Boolean}
+ * @api private
+ */
+
+SendStream.prototype.isCachable = function isCachable () {
+  var statusCode = this.res.statusCode
+  return (statusCode >= 200 && statusCode < 300) ||
+    statusCode === 304
+}
+
+/**
+ * Handle stat() error.
+ *
+ * @param {Error} error
+ * @private
+ */
+
+SendStream.prototype.onStatError = function onStatError (error) {
+  switch (error.code) {
+    case 'ENAMETOOLONG':
+    case 'ENOENT':
+    case 'ENOTDIR':
+      this.error(404, error)
+      break
+    default:
+      this.error(500, error)
+      break
+  }
+}
+
+/**
+ * Check if the cache is fresh.
+ *
+ * @return {Boolean}
+ * @api private
+ */
+
+SendStream.prototype.isFresh = function isFresh () {
+  return fresh(this.req.headers, {
+    etag: this.res.getHeader('ETag'),
+    'last-modified': this.res.getHeader('Last-Modified')
+  })
+}
+
+/**
+ * Check if the range is fresh.
+ *
+ * @return {Boolean}
+ * @api private
+ */
+
+SendStream.prototype.isRangeFresh = function isRangeFresh () {
+  var ifRange = this.req.headers['if-range']
+
+  if (!ifRange) {
+    return true
+  }
+
+  // if-range as etag
+  if (ifRange.indexOf('"') !== -1) {
+    var etag = this.res.getHeader('ETag')
+    return Boolean(etag && ifRange.indexOf(etag) !== -1)
+  }
+
+  // if-range as modified date
+  var lastModified = this.res.getHeader('Last-Modified')
+  return parseHttpDate(lastModified) <= parseHttpDate(ifRange)
+}
+
+/**
+ * Redirect to path.
+ *
+ * @param {string} path
+ * @private
+ */
+
+SendStream.prototype.redirect = function redirect (path) {
+  var res = this.res
+
+  if (hasListeners(this, 'directory')) {
+    this.emit('directory', res, path)
+    return
+  }
+
+  if (this.hasTrailingSlash()) {
+    this.error(403)
+    return
+  }
+
+  var loc = encodeUrl(collapseLeadingSlashes(this.path + '/'))
+  var doc = createHtmlDocument('Redirecting', 'Redirecting to ' + escapeHtml(loc))
+
+  // redirect
+  res.statusCode = 301
+  res.setHeader('Content-Type', 'text/html; charset=UTF-8')
+  res.setHeader('Content-Length', Buffer.byteLength(doc))
+  res.setHeader('Content-Security-Policy', "default-src 'none'")
+  res.setHeader('X-Content-Type-Options', 'nosniff')
+  res.setHeader('Location', loc)
+  res.end(doc)
+}
+
+/**
+ * Pipe to `res.
+ *
+ * @param {Stream} res
+ * @return {Stream} res
+ * @api public
+ */
+
+SendStream.prototype.pipe = function pipe (res) {
+  // root path
+  var root = this._root
+
+  // references
+  this.res = res
+
+  // decode the path
+  var path = decode(this.path)
+  if (path === -1) {
+    this.error(400)
+    return res
+  }
+
+  // null byte(s)
+  if (~path.indexOf('\0')) {
+    this.error(400)
+    return res
+  }
+
+  var parts
+  if (root !== null) {
+    // normalize
+    if (path) {
+      path = normalize('.' + sep + path)
+    }
+
+    // malicious path
+    if (UP_PATH_REGEXP.test(path)) {
+      debug('malicious path "%s"', path)
+      this.error(403)
+      return res
+    }
+
+    // explode path parts
+    parts = path.split(sep)
+
+    // join / normalize from optional root dir
+    path = normalize(join(root, path))
+  } else {
+    // ".." is malicious without "root"
+    if (UP_PATH_REGEXP.test(path)) {
+      debug('malicious path "%s"', path)
+      this.error(403)
+      return res
+    }
+
+    // explode path parts
+    parts = normalize(path).split(sep)
+
+    // resolve the path
+    path = resolve(path)
+  }
+
+  // dotfile handling
+  if (containsDotFile(parts)) {
+    var access = this._dotfiles
+
+    // legacy support
+    if (access === undefined) {
+      access = parts[parts.length - 1][0] === '.'
+        ? (this._hidden ? 'allow' : 'ignore')
+        : 'allow'
+    }
+
+    debug('%s dotfile "%s"', access, path)
+    switch (access) {
+      case 'allow':
+        break
+      case 'deny':
+        this.error(403)
+        return res
+      case 'ignore':
+      default:
+        this.error(404)
+        return res
+    }
+  }
+
+  // index file support
+  if (this._index.length && this.hasTrailingSlash()) {
+    this.sendIndex(path)
+    return res
+  }
+
+  this.sendFile(path)
+  return res
+}
+
+/**
+ * Transfer `path`.
+ *
+ * @param {String} path
+ * @api public
+ */
+
+SendStream.prototype.send = function send (path, stat) {
+  var len = stat.size
+  var options = this.options
+  var opts = {}
+  var res = this.res
+  var req = this.req
+  var ranges = req.headers.range
+  var offset = options.start || 0
+
+  if (headersSent(res)) {
+    // impossible to send now
+    this.headersAlreadySent()
+    return
+  }
+
+  debug('pipe "%s"', path)
+
+  // set header fields
+  this.setHeader(path, stat)
+
+  // set content-type
+  this.type(path)
+
+  // conditional GET support
+  if (this.isConditionalGET()) {
+    if (this.isPreconditionFailure()) {
+      this.error(412)
+      return
+    }
+
+    if (this.isCachable() && this.isFresh()) {
+      this.notModified()
+      return
+    }
+  }
+
+  // adjust len to start/end options
+  len = Math.max(0, len - offset)
+  if (options.end !== undefined) {
+    var bytes = options.end - offset + 1
+    if (len > bytes) len = bytes
+  }
+
+  // Range support
+  if (this._acceptRanges && BYTES_RANGE_REGEXP.test(ranges)) {
+    // parse
+    ranges = parseRange(len, ranges, {
+      combine: true
+    })
+
+    // If-Range support
+    if (!this.isRangeFresh()) {
+      debug('range stale')
+      ranges = -2
+    }
+
+    // unsatisfiable
+    if (ranges === -1) {
+      debug('range unsatisfiable')
+
+      // Content-Range
+      res.setHeader('Content-Range', contentRange('bytes', len))
+
+      // 416 Requested Range Not Satisfiable
+      return this.error(416, {
+        headers: { 'Content-Range': res.getHeader('Content-Range') }
+      })
+    }
+
+    // valid (syntactically invalid/multiple ranges are treated as a regular response)
+    if (ranges !== -2 && ranges.length === 1) {
+      debug('range %j', ranges)
+
+      // Content-Range
+      res.statusCode = 206
+      res.setHeader('Content-Range', contentRange('bytes', len, ranges[0]))
+
+      // adjust for requested range
+      offset += ranges[0].start
+      len = ranges[0].end - ranges[0].start + 1
+    }
+  }
+
+  // clone options
+  for (var prop in options) {
+    opts[prop] = options[prop]
+  }
+
+  // set read options
+  opts.start = offset
+  opts.end = Math.max(offset, offset + len - 1)
+
+  // content-length
+  res.setHeader('Content-Length', len)
+
+  // HEAD support
+  if (req.method === 'HEAD') {
+    res.end()
+    return
+  }
+
+  this.stream(path, opts)
+}
+
+/**
+ * Transfer file for `path`.
+ *
+ * @param {String} path
+ * @api private
+ */
+SendStream.prototype.sendFile = function sendFile (path) {
+  var i = 0
+  var self = this
+
+  debug('stat "%s"', path)
+  fs.stat(path, function onstat (err, stat) {
+    if (err && err.code === 'ENOENT' && !extname(path) && path[path.length - 1] !== sep) {
+      // not found, check extensions
+      return next(err)
+    }
+    if (err) return self.onStatError(err)
+    if (stat.isDirectory()) return self.redirect(path)
+    self.emit('file', path, stat)
+    self.send(path, stat)
+  })
+
+  function next (err) {
+    if (self._extensions.length <= i) {
+      return err
+        ? self.onStatError(err)
+        : self.error(404)
+    }
+
+    var p = path + '.' + self._extensions[i++]
+
+    debug('stat "%s"', p)
+    fs.stat(p, function (err, stat) {
+      if (err) return next(err)
+      if (stat.isDirectory()) return next()
+      self.emit('file', p, stat)
+      self.send(p, stat)
+    })
+  }
+}
+
+/**
+ * Transfer index for `path`.
+ *
+ * @param {String} path
+ * @api private
+ */
+SendStream.prototype.sendIndex = function sendIndex (path) {
+  var i = -1
+  var self = this
+
+  function next (err) {
+    if (++i >= self._index.length) {
+      if (err) return self.onStatError(err)
+      return self.error(404)
+    }
+
+    var p = join(path, self._index[i])
+
+    debug('stat "%s"', p)
+    fs.stat(p, function (err, stat) {
+      if (err) return next(err)
+      if (stat.isDirectory()) return next()
+      self.emit('file', p, stat)
+      self.send(p, stat)
+    })
+  }
+
+  next()
+}
+
+/**
+ * Stream `path` to the response.
+ *
+ * @param {String} path
+ * @param {Object} options
+ * @api private
+ */
+
+SendStream.prototype.stream = function stream (path, options) {
+  var self = this
+  var res = this.res
+
+  // pipe
+  var stream = fs.createReadStream(path, options)
+  this.emit('stream', stream)
+  stream.pipe(res)
+
+  // cleanup
+  function cleanup () {
+    destroy(stream, true)
+  }
+
+  // response finished, cleanup
+  onFinished(res, cleanup)
+
+  // error handling
+  stream.on('error', function onerror (err) {
+    // clean up stream early
+    cleanup()
+
+    // error
+    self.onStatError(err)
+  })
+
+  // end
+  stream.on('end', function onend () {
+    self.emit('end')
+  })
+}
+
+/**
+ * Set content-type based on `path`
+ * if it hasn't been explicitly set.
+ *
+ * @param {String} path
+ * @api private
+ */
+
+SendStream.prototype.type = function type (path) {
+  var res = this.res
+
+  if (res.getHeader('Content-Type')) return
+
+  var type = mime.lookup(path)
+
+  if (!type) {
+    debug('no content-type')
+    return
+  }
+
+  var charset = mime.charsets.lookup(type)
+
+  debug('content-type %s', type)
+  res.setHeader('Content-Type', type + (charset ? '; charset=' + charset : ''))
+}
+
+/**
+ * Set response header fields, most
+ * fields may be pre-defined.
+ *
+ * @param {String} path
+ * @param {Object} stat
+ * @api private
+ */
+
+SendStream.prototype.setHeader = function setHeader (path, stat) {
+  var res = this.res
+
+  this.emit('headers', res, path, stat)
+
+  if (this._acceptRanges && !res.getHeader('Accept-Ranges')) {
+    debug('accept ranges')
+    res.setHeader('Accept-Ranges', 'bytes')
+  }
+
+  if (this._cacheControl && !res.getHeader('Cache-Control')) {
+    var cacheControl = 'public, max-age=' + Math.floor(this._maxage / 1000)
+
+    if (this._immutable) {
+      cacheControl += ', immutable'
+    }
+
+    debug('cache-control %s', cacheControl)
+    res.setHeader('Cache-Control', cacheControl)
+  }
+
+  if (this._lastModified && !res.getHeader('Last-Modified')) {
+    var modified = stat.mtime.toUTCString()
+    debug('modified %s', modified)
+    res.setHeader('Last-Modified', modified)
+  }
+
+  if (this._etag && !res.getHeader('ETag')) {
+    var val = etag(stat)
+    debug('etag %s', val)
+    res.setHeader('ETag', val)
+  }
+}
+
+/**
+ * Clear all headers from a response.
+ *
+ * @param {object} res
+ * @private
+ */
+
+function clearHeaders (res) {
+  var headers = getHeaderNames(res)
+
+  for (var i = 0; i < headers.length; i++) {
+    res.removeHeader(headers[i])
+  }
+}
+
+/**
+ * Collapse all leading slashes into a single slash
+ *
+ * @param {string} str
+ * @private
+ */
+function collapseLeadingSlashes (str) {
+  for (var i = 0; i < str.length; i++) {
+    if (str[i] !== '/') {
+      break
+    }
+  }
+
+  return i > 1
+    ? '/' + str.substr(i)
+    : str
+}
+
+/**
+ * Determine if path parts contain a dotfile.
+ *
+ * @api private
+ */
+
+function containsDotFile (parts) {
+  for (var i = 0; i < parts.length; i++) {
+    var part = parts[i]
+    if (part.length > 1 && part[0] === '.') {
+      return true
+    }
+  }
+
+  return false
+}
+
+/**
+ * Create a Content-Range header.
+ *
+ * @param {string} type
+ * @param {number} size
+ * @param {array} [range]
+ */
+
+function contentRange (type, size, range) {
+  return type + ' ' + (range ? range.start + '-' + range.end : '*') + '/' + size
+}
+
+/**
+ * Create a minimal HTML document.
+ *
+ * @param {string} title
+ * @param {string} body
+ * @private
+ */
+
+function createHtmlDocument (title, body) {
+  return '<!DOCTYPE html>\n' +
+    '<html lang="en">\n' +
+    '<head>\n' +
+    '<meta charset="utf-8">\n' +
+    '<title>' + title + '</title>\n' +
+    '</head>\n' +
+    '<body>\n' +
+    '<pre>' + body + '</pre>\n' +
+    '</body>\n' +
+    '</html>\n'
+}
+
+/**
+ * Create a HttpError object from simple arguments.
+ *
+ * @param {number} status
+ * @param {Error|object} err
+ * @private
+ */
+
+function createHttpError (status, err) {
+  if (!err) {
+    return createError(status)
+  }
+
+  return err instanceof Error
+    ? createError(status, err, { expose: false })
+    : createError(status, err)
+}
+
+/**
+ * decodeURIComponent.
+ *
+ * Allows V8 to only deoptimize this fn instead of all
+ * of send().
+ *
+ * @param {String} path
+ * @api private
+ */
+
+function decode (path) {
+  try {
+    return decodeURIComponent(path)
+  } catch (err) {
+    return -1
+  }
+}
+
+/**
+ * Get the header names on a respnse.
+ *
+ * @param {object} res
+ * @returns {array[string]}
+ * @private
+ */
+
+function getHeaderNames (res) {
+  return typeof res.getHeaderNames !== 'function'
+    ? Object.keys(res._headers || {})
+    : res.getHeaderNames()
+}
+
+/**
+ * Determine if emitter has listeners of a given type.
+ *
+ * The way to do this check is done three different ways in Node.js >= 0.8
+ * so this consolidates them into a minimal set using instance methods.
+ *
+ * @param {EventEmitter} emitter
+ * @param {string} type
+ * @returns {boolean}
+ * @private
+ */
+
+function hasListeners (emitter, type) {
+  var count = typeof emitter.listenerCount !== 'function'
+    ? emitter.listeners(type).length
+    : emitter.listenerCount(type)
+
+  return count > 0
+}
+
+/**
+ * Determine if the response headers have been sent.
+ *
+ * @param {object} res
+ * @returns {boolean}
+ * @private
+ */
+
+function headersSent (res) {
+  return typeof res.headersSent !== 'boolean'
+    ? Boolean(res._header)
+    : res.headersSent
+}
+
+/**
+ * Normalize the index option into an array.
+ *
+ * @param {boolean|string|array} val
+ * @param {string} name
+ * @private
+ */
+
+function normalizeList (val, name) {
+  var list = [].concat(val || [])
+
+  for (var i = 0; i < list.length; i++) {
+    if (typeof list[i] !== 'string') {
+      throw new TypeError(name + ' must be array of strings or false')
+    }
+  }
+
+  return list
+}
+
+/**
+ * Parse an HTTP Date into a number.
+ *
+ * @param {string} date
+ * @private
+ */
+
+function parseHttpDate (date) {
+  var timestamp = date && Date.parse(date)
+
+  return typeof timestamp === 'number'
+    ? timestamp
+    : NaN
+}
+
+/**
+ * Parse a HTTP token list.
+ *
+ * @param {string} str
+ * @private
+ */
+
+function parseTokenList (str) {
+  var end = 0
+  var list = []
+  var start = 0
+
+  // gather tokens
+  for (var i = 0, len = str.length; i < len; i++) {
+    switch (str.charCodeAt(i)) {
+      case 0x20: /*   */
+        if (start === end) {
+          start = end = i + 1
+        }
+        break
+      case 0x2c: /* , */
+        if (start !== end) {
+          list.push(str.substring(start, end))
+        }
+        start = end = i + 1
+        break
+      default:
+        end = i + 1
+        break
+    }
+  }
+
+  // final token
+  if (start !== end) {
+    list.push(str.substring(start, end))
+  }
+
+  return list
+}
+
+/**
+ * Set an object of headers on a response.
+ *
+ * @param {object} res
+ * @param {object} headers
+ * @private
+ */
+
+function setHeaders (res, headers) {
+  var keys = Object.keys(headers)
+
+  for (var i = 0; i < keys.length; i++) {
+    var key = keys[i]
+    res.setHeader(key, headers[key])
+  }
+}
diff --git a/server/node_modules/send/node_modules/ms/index.js b/server/node_modules/send/node_modules/ms/index.js
new file mode 100644
index 0000000..ea734fb
--- /dev/null
+++ b/server/node_modules/send/node_modules/ms/index.js
@@ -0,0 +1,162 @@
+/**
+ * Helpers.
+ */
+
+var s = 1000;
+var m = s * 60;
+var h = m * 60;
+var d = h * 24;
+var w = d * 7;
+var y = d * 365.25;
+
+/**
+ * Parse or format the given `val`.
+ *
+ * Options:
+ *
+ *  - `long` verbose formatting [false]
+ *
+ * @param {String|Number} val
+ * @param {Object} [options]
+ * @throws {Error} throw an error if val is not a non-empty string or a number
+ * @return {String|Number}
+ * @api public
+ */
+
+module.exports = function (val, options) {
+  options = options || {};
+  var type = typeof val;
+  if (type === 'string' && val.length > 0) {
+    return parse(val);
+  } else if (type === 'number' && isFinite(val)) {
+    return options.long ? fmtLong(val) : fmtShort(val);
+  }
+  throw new Error(
+    'val is not a non-empty string or a valid number. val=' +
+      JSON.stringify(val)
+  );
+};
+
+/**
+ * Parse the given `str` and return milliseconds.
+ *
+ * @param {String} str
+ * @return {Number}
+ * @api private
+ */
+
+function parse(str) {
+  str = String(str);
+  if (str.length > 100) {
+    return;
+  }
+  var match = /^(-?(?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|weeks?|w|years?|yrs?|y)?$/i.exec(
+    str
+  );
+  if (!match) {
+    return;
+  }
+  var n = parseFloat(match[1]);
+  var type = (match[2] || 'ms').toLowerCase();
+  switch (type) {
+    case 'years':
+    case 'year':
+    case 'yrs':
+    case 'yr':
+    case 'y':
+      return n * y;
+    case 'weeks':
+    case 'week':
+    case 'w':
+      return n * w;
+    case 'days':
+    case 'day':
+    case 'd':
+      return n * d;
+    case 'hours':
+    case 'hour':
+    case 'hrs':
+    case 'hr':
+    case 'h':
+      return n * h;
+    case 'minutes':
+    case 'minute':
+    case 'mins':
+    case 'min':
+    case 'm':
+      return n * m;
+    case 'seconds':
+    case 'second':
+    case 'secs':
+    case 'sec':
+    case 's':
+      return n * s;
+    case 'milliseconds':
+    case 'millisecond':
+    case 'msecs':
+    case 'msec':
+    case 'ms':
+      return n;
+    default:
+      return undefined;
+  }
+}
+
+/**
+ * Short format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtShort(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return Math.round(ms / d) + 'd';
+  }
+  if (msAbs >= h) {
+    return Math.round(ms / h) + 'h';
+  }
+  if (msAbs >= m) {
+    return Math.round(ms / m) + 'm';
+  }
+  if (msAbs >= s) {
+    return Math.round(ms / s) + 's';
+  }
+  return ms + 'ms';
+}
+
+/**
+ * Long format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtLong(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return plural(ms, msAbs, d, 'day');
+  }
+  if (msAbs >= h) {
+    return plural(ms, msAbs, h, 'hour');
+  }
+  if (msAbs >= m) {
+    return plural(ms, msAbs, m, 'minute');
+  }
+  if (msAbs >= s) {
+    return plural(ms, msAbs, s, 'second');
+  }
+  return ms + ' ms';
+}
+
+/**
+ * Pluralization helper.
+ */
+
+function plural(ms, msAbs, n, name) {
+  var isPlural = msAbs >= n * 1.5;
+  return Math.round(ms / n) + ' ' + name + (isPlural ? 's' : '');
+}
diff --git a/server/node_modules/send/node_modules/ms/license.md b/server/node_modules/send/node_modules/ms/license.md
new file mode 100644
index 0000000..fa5d39b
--- /dev/null
+++ b/server/node_modules/send/node_modules/ms/license.md
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2020 Vercel, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/send/node_modules/ms/package.json b/server/node_modules/send/node_modules/ms/package.json
new file mode 100644
index 0000000..4997189
--- /dev/null
+++ b/server/node_modules/send/node_modules/ms/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "ms",
+  "version": "2.1.3",
+  "description": "Tiny millisecond conversion utility",
+  "repository": "vercel/ms",
+  "main": "./index",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "precommit": "lint-staged",
+    "lint": "eslint lib/* bin/*",
+    "test": "mocha tests.js"
+  },
+  "eslintConfig": {
+    "extends": "eslint:recommended",
+    "env": {
+      "node": true,
+      "es6": true
+    }
+  },
+  "lint-staged": {
+    "*.js": [
+      "npm run lint",
+      "prettier --single-quote --write",
+      "git add"
+    ]
+  },
+  "license": "MIT",
+  "devDependencies": {
+    "eslint": "4.18.2",
+    "expect.js": "0.3.1",
+    "husky": "0.14.3",
+    "lint-staged": "5.0.0",
+    "mocha": "4.0.1",
+    "prettier": "2.0.5"
+  }
+}
diff --git a/server/node_modules/send/node_modules/ms/readme.md b/server/node_modules/send/node_modules/ms/readme.md
new file mode 100644
index 0000000..0fc1abb
--- /dev/null
+++ b/server/node_modules/send/node_modules/ms/readme.md
@@ -0,0 +1,59 @@
+# ms
+
+![CI](https://github.com/vercel/ms/workflows/CI/badge.svg)
+
+Use this package to easily convert various time formats to milliseconds.
+
+## Examples
+
+```js
+ms('2 days')  // 172800000
+ms('1d')      // 86400000
+ms('10h')     // 36000000
+ms('2.5 hrs') // 9000000
+ms('2h')      // 7200000
+ms('1m')      // 60000
+ms('5s')      // 5000
+ms('1y')      // 31557600000
+ms('100')     // 100
+ms('-3 days') // -259200000
+ms('-1h')     // -3600000
+ms('-200')    // -200
+```
+
+### Convert from Milliseconds
+
+```js
+ms(60000)             // "1m"
+ms(2 * 60000)         // "2m"
+ms(-3 * 60000)        // "-3m"
+ms(ms('10 hours'))    // "10h"
+```
+
+### Time Format Written-Out
+
+```js
+ms(60000, { long: true })             // "1 minute"
+ms(2 * 60000, { long: true })         // "2 minutes"
+ms(-3 * 60000, { long: true })        // "-3 minutes"
+ms(ms('10 hours'), { long: true })    // "10 hours"
+```
+
+## Features
+
+- Works both in [Node.js](https://nodejs.org) and in the browser
+- If a number is supplied to `ms`, a string with a unit is returned
+- If a string that contains the number is supplied, it returns it as a number (e.g.: it returns `100` for `'100'`)
+- If you pass a string with a number and a valid unit, the number of equivalent milliseconds is returned
+
+## Related Packages
+
+- [ms.macro](https://github.com/knpwrs/ms.macro) - Run `ms` as a macro at build-time.
+
+## Caught a Bug?
+
+1. [Fork](https://help.github.com/articles/fork-a-repo/) this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device
+2. Link the package to the global module directory: `npm link`
+3. Within the module you want to test your local development instance of ms, just link it to the dependencies: `npm link ms`. Instead of the default one from npm, Node.js will now use your clone of ms!
+
+As always, you can run the tests using: `npm test`
diff --git a/server/node_modules/send/package.json b/server/node_modules/send/package.json
new file mode 100644
index 0000000..2d2b805
--- /dev/null
+++ b/server/node_modules/send/package.json
@@ -0,0 +1,62 @@
+{
+  "name": "send",
+  "description": "Better streaming static file server with Range and conditional-GET support",
+  "version": "0.19.2",
+  "author": "TJ Holowaychuk <tj@vision-media.ca>",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "James Wyatt Cready <jcready@gmail.com>",
+    "Jesús Leganés Combarro <piranna@gmail.com>"
+  ],
+  "license": "MIT",
+  "repository": "pillarjs/send",
+  "keywords": [
+    "static",
+    "file",
+    "server"
+  ],
+  "dependencies": {
+    "debug": "2.6.9",
+    "depd": "2.0.0",
+    "destroy": "1.2.0",
+    "encodeurl": "~2.0.0",
+    "escape-html": "~1.0.3",
+    "etag": "~1.8.1",
+    "fresh": "~0.5.2",
+    "http-errors": "~2.0.1",
+    "mime": "1.6.0",
+    "ms": "2.1.3",
+    "on-finished": "~2.4.1",
+    "range-parser": "~1.2.1",
+    "statuses": "~2.0.2"
+  },
+  "devDependencies": {
+    "after": "0.8.2",
+    "eslint": "7.32.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.25.4",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "5.2.0",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "9.2.2",
+    "nyc": "15.1.0",
+    "supertest": "6.2.2"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "README.md",
+    "SECURITY.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8.0"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --check-leaks --reporter spec --bail",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test"
+  }
+}
diff --git a/server/node_modules/serve-static/HISTORY.md b/server/node_modules/serve-static/HISTORY.md
new file mode 100644
index 0000000..9919669
--- /dev/null
+++ b/server/node_modules/serve-static/HISTORY.md
@@ -0,0 +1,493 @@
+1.16.3 / 2024-12-15
+===================
+
+* deps: send@~0.19.1
+  - deps: encodeurl@~2.0.0 
+
+1.16.2 / 2024-09-11
+===================
+
+* deps: encodeurl@~2.0.0
+
+1.16.1 / 2024-09-11
+===================
+
+* deps: send@0.19.0
+
+1.16.0 / 2024-09-10
+===================
+
+* Remove link renderization in html while redirecting
+
+
+1.15.0 / 2022-03-24
+===================
+
+  * deps: send@0.18.0
+    - Fix emitted 416 error missing headers property
+    - Limit the headers removed for 304 response
+    - deps: depd@2.0.0
+    - deps: destroy@1.2.0
+    - deps: http-errors@2.0.0
+    - deps: on-finished@2.4.1
+    - deps: statuses@2.0.1
+
+1.14.2 / 2021-12-15
+===================
+
+  * deps: send@0.17.2
+    - deps: http-errors@1.8.1
+    - deps: ms@2.1.3
+    - pref: ignore empty http tokens
+
+1.14.1 / 2019-05-10
+===================
+
+  * Set stricter CSP header in redirect response
+  * deps: send@0.17.1
+    - deps: range-parser@~1.2.1
+
+1.14.0 / 2019-05-07
+===================
+
+  * deps: parseurl@~1.3.3
+  * deps: send@0.17.0
+    - deps: http-errors@~1.7.2
+    - deps: mime@1.6.0
+    - deps: ms@2.1.1
+    - deps: statuses@~1.5.0
+    - perf: remove redundant `path.normalize` call
+
+1.13.2 / 2018-02-07
+===================
+
+  * Fix incorrect end tag in redirects
+  * deps: encodeurl@~1.0.2
+    - Fix encoding `%` as last character
+  * deps: send@0.16.2
+    - deps: depd@~1.1.2
+    - deps: encodeurl@~1.0.2
+    - deps: statuses@~1.4.0
+
+1.13.1 / 2017-09-29
+===================
+
+  * Fix regression when `root` is incorrectly set to a file
+  * deps: send@0.16.1
+
+1.13.0 / 2017-09-27
+===================
+
+  * deps: send@0.16.0
+    - Add 70 new types for file extensions
+    - Add `immutable` option
+    - Fix missing `</html>` in default error & redirects
+    - Set charset as "UTF-8" for .js and .json
+    - Use instance methods on steam to check for listeners
+    - deps: mime@1.4.1
+    - perf: improve path validation speed
+
+1.12.6 / 2017-09-22
+===================
+
+  * deps: send@0.15.6
+    - deps: debug@2.6.9
+    - perf: improve `If-Match` token parsing
+  * perf: improve slash collapsing
+
+1.12.5 / 2017-09-21
+===================
+
+  * deps: parseurl@~1.3.2
+    - perf: reduce overhead for full URLs
+    - perf: unroll the "fast-path" `RegExp`
+  * deps: send@0.15.5
+    - Fix handling of modified headers with invalid dates
+    - deps: etag@~1.8.1
+    - deps: fresh@0.5.2
+
+1.12.4 / 2017-08-05
+===================
+
+  * deps: send@0.15.4
+    - deps: debug@2.6.8
+    - deps: depd@~1.1.1
+    - deps: http-errors@~1.6.2
+
+1.12.3 / 2017-05-16
+===================
+
+  * deps: send@0.15.3
+    - deps: debug@2.6.7
+
+1.12.2 / 2017-04-26
+===================
+
+  * deps: send@0.15.2
+    - deps: debug@2.6.4
+
+1.12.1 / 2017-03-04
+===================
+
+  * deps: send@0.15.1
+    - Fix issue when `Date.parse` does not return `NaN` on invalid date
+    - Fix strict violation in broken environments
+
+1.12.0 / 2017-02-25
+===================
+
+  * Send complete HTML document in redirect response
+  * Set default CSP header in redirect response
+  * deps: send@0.15.0
+    - Fix false detection of `no-cache` request directive
+    - Fix incorrect result when `If-None-Match` has both `*` and ETags
+    - Fix weak `ETag` matching to match spec
+    - Remove usage of `res._headers` private field
+    - Support `If-Match` and `If-Unmodified-Since` headers
+    - Use `res.getHeaderNames()` when available
+    - Use `res.headersSent` when available
+    - deps: debug@2.6.1
+    - deps: etag@~1.8.0
+    - deps: fresh@0.5.0
+    - deps: http-errors@~1.6.1
+
+1.11.2 / 2017-01-23
+===================
+
+  * deps: send@0.14.2
+    - deps: http-errors@~1.5.1
+    - deps: ms@0.7.2
+    - deps: statuses@~1.3.1
+
+1.11.1 / 2016-06-10
+===================
+
+  * Fix redirect error when `req.url` contains raw non-URL characters
+  * deps: send@0.14.1
+
+1.11.0 / 2016-06-07
+===================
+
+  * Use status code 301 for redirects
+  * deps: send@0.14.0
+    - Add `acceptRanges` option
+    - Add `cacheControl` option
+    - Attempt to combine multiple ranges into single range
+    - Correctly inherit from `Stream` class
+    - Fix `Content-Range` header in 416 responses when using `start`/`end` options
+    - Fix `Content-Range` header missing from default 416 responses
+    - Ignore non-byte `Range` headers
+    - deps: http-errors@~1.5.0
+    - deps: range-parser@~1.2.0
+    - deps: statuses@~1.3.0
+    - perf: remove argument reassignment
+
+1.10.3 / 2016-05-30
+===================
+
+  * deps: send@0.13.2
+    - Fix invalid `Content-Type` header when `send.mime.default_type` unset
+
+1.10.2 / 2016-01-19
+===================
+
+  * deps: parseurl@~1.3.1
+    - perf: enable strict mode
+
+1.10.1 / 2016-01-16
+===================
+
+  * deps: escape-html@~1.0.3
+    - perf: enable strict mode
+    - perf: optimize string replacement
+    - perf: use faster string coercion
+  * deps: send@0.13.1
+    - deps: depd@~1.1.0
+    - deps: destroy@~1.0.4
+    - deps: escape-html@~1.0.3
+    - deps: range-parser@~1.0.3
+
+1.10.0 / 2015-06-17
+===================
+
+  * Add `fallthrough` option
+    - Allows declaring this middleware is the final destination
+    - Provides better integration with Express patterns
+  * Fix reading options from options prototype
+  * Improve the default redirect response headers
+  * deps: escape-html@1.0.2
+  * deps: send@0.13.0
+    - Allow Node.js HTTP server to set `Date` response header
+    - Fix incorrectly removing `Content-Location` on 304 response
+    - Improve the default redirect response headers
+    - Send appropriate headers on default error response
+    - Use `http-errors` for standard emitted errors
+    - Use `statuses` instead of `http` module for status messages
+    - deps: escape-html@1.0.2
+    - deps: etag@~1.7.0
+    - deps: fresh@0.3.0
+    - deps: on-finished@~2.3.0
+    - perf: enable strict mode
+    - perf: remove unnecessary array allocations
+  * perf: enable strict mode
+  * perf: remove argument reassignment
+
+1.9.3 / 2015-05-14
+==================
+
+  * deps: send@0.12.3
+    - deps: debug@~2.2.0
+    - deps: depd@~1.0.1
+    - deps: etag@~1.6.0
+    - deps: ms@0.7.1
+    - deps: on-finished@~2.2.1
+
+1.9.2 / 2015-03-14
+==================
+
+  * deps: send@0.12.2
+    - Throw errors early for invalid `extensions` or `index` options
+    - deps: debug@~2.1.3
+
+1.9.1 / 2015-02-17
+==================
+
+  * deps: send@0.12.1
+    - Fix regression sending zero-length files
+
+1.9.0 / 2015-02-16
+==================
+
+  * deps: send@0.12.0
+    - Always read the stat size from the file
+    - Fix mutating passed-in `options`
+    - deps: mime@1.3.4
+
+1.8.1 / 2015-01-20
+==================
+
+  * Fix redirect loop in Node.js 0.11.14
+  * deps: send@0.11.1
+    - Fix root path disclosure
+
+1.8.0 / 2015-01-05
+==================
+
+  * deps: send@0.11.0
+    - deps: debug@~2.1.1
+    - deps: etag@~1.5.1
+    - deps: ms@0.7.0
+    - deps: on-finished@~2.2.0
+
+1.7.2 / 2015-01-02
+==================
+
+  * Fix potential open redirect when mounted at root
+
+1.7.1 / 2014-10-22
+==================
+
+  * deps: send@0.10.1
+    - deps: on-finished@~2.1.1
+
+1.7.0 / 2014-10-15
+==================
+
+  * deps: send@0.10.0
+    - deps: debug@~2.1.0
+    - deps: depd@~1.0.0
+    - deps: etag@~1.5.0
+
+1.6.5 / 2015-02-04
+==================
+
+  * Fix potential open redirect when mounted at root
+    - Back-ported from v1.7.2
+
+1.6.4 / 2014-10-08
+==================
+
+  * Fix redirect loop when index file serving disabled
+
+1.6.3 / 2014-09-24
+==================
+
+  * deps: send@0.9.3
+    - deps: etag@~1.4.0
+
+1.6.2 / 2014-09-15
+==================
+
+  * deps: send@0.9.2
+    - deps: depd@0.4.5
+    - deps: etag@~1.3.1
+    - deps: range-parser@~1.0.2
+
+1.6.1 / 2014-09-07
+==================
+
+  * deps: send@0.9.1
+    - deps: fresh@0.2.4
+
+1.6.0 / 2014-09-07
+==================
+
+  * deps: send@0.9.0
+    - Add `lastModified` option
+    - Use `etag` to generate `ETag` header
+    - deps: debug@~2.0.0
+
+1.5.4 / 2014-09-04
+==================
+
+  * deps: send@0.8.5
+    - Fix a path traversal issue when using `root`
+    - Fix malicious path detection for empty string path
+
+1.5.3 / 2014-08-17
+==================
+
+  * deps: send@0.8.3
+
+1.5.2 / 2014-08-14
+==================
+
+  * deps: send@0.8.2
+    - Work around `fd` leak in Node.js 0.10 for `fs.ReadStream`
+
+1.5.1 / 2014-08-09
+==================
+
+  * Fix parsing of weird `req.originalUrl` values
+  * deps: parseurl@~1.3.0
+  * deps: utils-merge@1.0.0
+
+1.5.0 / 2014-08-05
+==================
+
+  * deps: send@0.8.1
+    - Add `extensions` option
+
+1.4.4 / 2014-08-04
+==================
+
+  * deps: send@0.7.4
+    - Fix serving index files without root dir
+
+1.4.3 / 2014-07-29
+==================
+
+  * deps: send@0.7.3
+    - Fix incorrect 403 on Windows and Node.js 0.11
+
+1.4.2 / 2014-07-27
+==================
+
+  * deps: send@0.7.2
+    - deps: depd@0.4.4
+
+1.4.1 / 2014-07-26
+==================
+
+  * deps: send@0.7.1
+    - deps: depd@0.4.3
+
+1.4.0 / 2014-07-21
+==================
+
+  * deps: parseurl@~1.2.0
+    - Cache URLs based on original value
+    - Remove no-longer-needed URL mis-parse work-around
+    - Simplify the "fast-path" `RegExp`
+  * deps: send@0.7.0
+    - Add `dotfiles` option
+    - deps: debug@1.0.4
+    - deps: depd@0.4.2
+
+1.3.2 / 2014-07-11
+==================
+
+  * deps: send@0.6.0
+    - Cap `maxAge` value to 1 year
+    - deps: debug@1.0.3
+
+1.3.1 / 2014-07-09
+==================
+
+  * deps: parseurl@~1.1.3
+    - faster parsing of href-only URLs
+
+1.3.0 / 2014-06-28
+==================
+
+  * Add `setHeaders` option
+  * Include HTML link in redirect response
+  * deps: send@0.5.0
+    - Accept string for `maxAge` (converted by `ms`)
+
+1.2.3 / 2014-06-11
+==================
+
+  * deps: send@0.4.3
+    - Do not throw un-catchable error on file open race condition
+    - Use `escape-html` for HTML escaping
+    - deps: debug@1.0.2
+    - deps: finished@1.2.2
+    - deps: fresh@0.2.2
+
+1.2.2 / 2014-06-09
+==================
+
+  * deps: send@0.4.2
+    - fix "event emitter leak" warnings
+    - deps: debug@1.0.1
+    - deps: finished@1.2.1
+
+1.2.1 / 2014-06-02
+==================
+
+  * use `escape-html` for escaping
+  * deps: send@0.4.1
+    - Send `max-age` in `Cache-Control` in correct format
+
+1.2.0 / 2014-05-29
+==================
+
+  * deps: send@0.4.0
+    - Calculate ETag with md5 for reduced collisions
+    - Fix wrong behavior when index file matches directory
+    - Ignore stream errors after request ends
+    - Skip directories in index file search
+    - deps: debug@0.8.1
+
+1.1.0 / 2014-04-24
+==================
+
+  * Accept options directly to `send` module
+  * deps: send@0.3.0
+
+1.0.4 / 2014-04-07
+==================
+
+  * Resolve relative paths at middleware setup
+  * Use parseurl to parse the URL from request
+
+1.0.3 / 2014-03-20
+==================
+
+  * Do not rely on connect-like environments
+
+1.0.2 / 2014-03-06
+==================
+
+  * deps: send@0.2.0
+
+1.0.1 / 2014-03-05
+==================
+
+  * Add mime export for back-compat
+
+1.0.0 / 2014-03-05
+==================
+
+  * Genesis from `connect`
diff --git a/server/node_modules/serve-static/LICENSE b/server/node_modules/serve-static/LICENSE
new file mode 100644
index 0000000..cbe62e8
--- /dev/null
+++ b/server/node_modules/serve-static/LICENSE
@@ -0,0 +1,25 @@
+(The MIT License)
+
+Copyright (c) 2010 Sencha Inc.
+Copyright (c) 2011 LearnBoost
+Copyright (c) 2011 TJ Holowaychuk
+Copyright (c) 2014-2016 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/serve-static/README.md b/server/node_modules/serve-static/README.md
new file mode 100644
index 0000000..262d944
--- /dev/null
+++ b/server/node_modules/serve-static/README.md
@@ -0,0 +1,257 @@
+# serve-static
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Linux Build][github-actions-ci-image]][github-actions-ci-url]
+[![Windows Build][appveyor-image]][appveyor-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+## Install
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install serve-static
+```
+
+## API
+
+```js
+var serveStatic = require('serve-static')
+```
+
+### serveStatic(root, options)
+
+Create a new middleware function to serve files from within a given root
+directory. The file to serve will be determined by combining `req.url`
+with the provided root directory. When a file is not found, instead of
+sending a 404 response, this module will instead call `next()` to move on
+to the next middleware, allowing for stacking and fall-backs.
+
+#### Options
+
+##### acceptRanges
+
+Enable or disable accepting ranged requests, defaults to true.
+Disabling this will not send `Accept-Ranges` and ignore the contents
+of the `Range` request header.
+
+##### cacheControl
+
+Enable or disable setting `Cache-Control` response header, defaults to
+true. Disabling this will ignore the `immutable` and `maxAge` options.
+
+##### dotfiles
+
+ Set how "dotfiles" are treated when encountered. A dotfile is a file
+or directory that begins with a dot ("."). Note this check is done on
+the path itself without checking if the path actually exists on the
+disk. If `root` is specified, only the dotfiles above the root are
+checked (i.e. the root itself can be within a dotfile when set
+to "deny").
+
+  - `'allow'` No special treatment for dotfiles.
+  - `'deny'` Deny a request for a dotfile and 403/`next()`.
+  - `'ignore'` Pretend like the dotfile does not exist and 404/`next()`.
+
+The default value is similar to `'ignore'`, with the exception that this
+default will not ignore the files within a directory that begins with a dot.
+
+##### etag
+
+Enable or disable etag generation, defaults to true.
+
+##### extensions
+
+Set file extension fallbacks. When set, if a file is not found, the given
+extensions will be added to the file name and search for. The first that
+exists will be served. Example: `['html', 'htm']`.
+
+The default value is `false`.
+
+##### fallthrough
+
+Set the middleware to have client errors fall-through as just unhandled
+requests, otherwise forward a client error. The difference is that client
+errors like a bad request or a request to a non-existent file will cause
+this middleware to simply `next()` to your next middleware when this value
+is `true`. When this value is `false`, these errors (even 404s), will invoke
+`next(err)`.
+
+Typically `true` is desired such that multiple physical directories can be
+mapped to the same web address or for routes to fill in non-existent files.
+
+The value `false` can be used if this middleware is mounted at a path that
+is designed to be strictly a single file system directory, which allows for
+short-circuiting 404s for less overhead. This middleware will also reply to
+all methods.
+
+The default value is `true`.
+
+##### immutable
+
+Enable or disable the `immutable` directive in the `Cache-Control` response
+header, defaults to `false`. If set to `true`, the `maxAge` option should
+also be specified to enable caching. The `immutable` directive will prevent
+supported clients from making conditional requests during the life of the
+`maxAge` option to check if the file has changed.
+
+##### index
+
+By default this module will send "index.html" files in response to a request
+on a directory. To disable this set `false` or to supply a new index pass a
+string or an array in preferred order.
+
+##### lastModified
+
+Enable or disable `Last-Modified` header, defaults to true. Uses the file
+system's last modified value.
+
+##### maxAge
+
+Provide a max-age in milliseconds for http caching, defaults to 0. This
+can also be a string accepted by the [ms](https://www.npmjs.org/package/ms#readme)
+module.
+
+##### redirect
+
+Redirect to trailing "/" when the pathname is a dir. Defaults to `true`.
+
+##### setHeaders
+
+Function to set custom headers on response. Alterations to the headers need to
+occur synchronously. The function is called as `fn(res, path, stat)`, where
+the arguments are:
+
+  - `res` the response object
+  - `path` the file path that is being sent
+  - `stat` the stat object of the file that is being sent
+
+## Examples
+
+### Serve files with vanilla node.js http server
+
+```js
+var finalhandler = require('finalhandler')
+var http = require('http')
+var serveStatic = require('serve-static')
+
+// Serve up public/ftp folder
+var serve = serveStatic('public/ftp', { index: ['index.html', 'index.htm'] })
+
+// Create server
+var server = http.createServer(function onRequest (req, res) {
+  serve(req, res, finalhandler(req, res))
+})
+
+// Listen
+server.listen(3000)
+```
+
+### Serve all files as downloads
+
+```js
+var contentDisposition = require('content-disposition')
+var finalhandler = require('finalhandler')
+var http = require('http')
+var serveStatic = require('serve-static')
+
+// Serve up public/ftp folder
+var serve = serveStatic('public/ftp', {
+  index: false,
+  setHeaders: setHeaders
+})
+
+// Set header to force download
+function setHeaders (res, path) {
+  res.setHeader('Content-Disposition', contentDisposition(path))
+}
+
+// Create server
+var server = http.createServer(function onRequest (req, res) {
+  serve(req, res, finalhandler(req, res))
+})
+
+// Listen
+server.listen(3000)
+```
+
+### Serving using express
+
+#### Simple
+
+This is a simple example of using Express.
+
+```js
+var express = require('express')
+var serveStatic = require('serve-static')
+
+var app = express()
+
+app.use(serveStatic('public/ftp', { index: ['default.html', 'default.htm'] }))
+app.listen(3000)
+```
+
+#### Multiple roots
+
+This example shows a simple way to search through multiple directories.
+Files are searched for in `public-optimized/` first, then `public/` second
+as a fallback.
+
+```js
+var express = require('express')
+var path = require('path')
+var serveStatic = require('serve-static')
+
+var app = express()
+
+app.use(serveStatic(path.join(__dirname, 'public-optimized')))
+app.use(serveStatic(path.join(__dirname, 'public')))
+app.listen(3000)
+```
+
+#### Different settings for paths
+
+This example shows how to set a different max age depending on the served
+file type. In this example, HTML files are not cached, while everything else
+is for 1 day.
+
+```js
+var express = require('express')
+var path = require('path')
+var serveStatic = require('serve-static')
+
+var app = express()
+
+app.use(serveStatic(path.join(__dirname, 'public'), {
+  maxAge: '1d',
+  setHeaders: setCustomCacheControl
+}))
+
+app.listen(3000)
+
+function setCustomCacheControl (res, path) {
+  if (serveStatic.mime.lookup(path) === 'text/html') {
+    // Custom Cache-Control for HTML files
+    res.setHeader('Cache-Control', 'public, max-age=0')
+  }
+}
+```
+
+## License
+
+[MIT](LICENSE)
+
+[appveyor-image]: https://badgen.net/appveyor/ci/dougwilson/serve-static/master?label=windows
+[appveyor-url]: https://ci.appveyor.com/project/dougwilson/serve-static
+[coveralls-image]: https://badgen.net/coveralls/c/github/expressjs/serve-static/master
+[coveralls-url]: https://coveralls.io/r/expressjs/serve-static?branch=master
+[github-actions-ci-image]: https://badgen.net/github/checks/expressjs/serve-static/master?label=linux
+[github-actions-ci-url]: https://github.com/expressjs/serve-static/actions/workflows/ci.yml
+[node-image]: https://badgen.net/npm/node/serve-static
+[node-url]: https://nodejs.org/en/download/
+[npm-downloads-image]: https://badgen.net/npm/dm/serve-static
+[npm-url]: https://npmjs.org/package/serve-static
+[npm-version-image]: https://badgen.net/npm/v/serve-static
diff --git a/server/node_modules/serve-static/index.js b/server/node_modules/serve-static/index.js
new file mode 100644
index 0000000..3f3e64e
--- /dev/null
+++ b/server/node_modules/serve-static/index.js
@@ -0,0 +1,209 @@
+/*!
+ * serve-static
+ * Copyright(c) 2010 Sencha Inc.
+ * Copyright(c) 2011 TJ Holowaychuk
+ * Copyright(c) 2014-2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var encodeUrl = require('encodeurl')
+var escapeHtml = require('escape-html')
+var parseUrl = require('parseurl')
+var resolve = require('path').resolve
+var send = require('send')
+var url = require('url')
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = serveStatic
+module.exports.mime = send.mime
+
+/**
+ * @param {string} root
+ * @param {object} [options]
+ * @return {function}
+ * @public
+ */
+
+function serveStatic (root, options) {
+  if (!root) {
+    throw new TypeError('root path required')
+  }
+
+  if (typeof root !== 'string') {
+    throw new TypeError('root path must be a string')
+  }
+
+  // copy options object
+  var opts = Object.create(options || null)
+
+  // fall-though
+  var fallthrough = opts.fallthrough !== false
+
+  // default redirect
+  var redirect = opts.redirect !== false
+
+  // headers listener
+  var setHeaders = opts.setHeaders
+
+  if (setHeaders && typeof setHeaders !== 'function') {
+    throw new TypeError('option setHeaders must be function')
+  }
+
+  // setup options for send
+  opts.maxage = opts.maxage || opts.maxAge || 0
+  opts.root = resolve(root)
+
+  // construct directory listener
+  var onDirectory = redirect
+    ? createRedirectDirectoryListener()
+    : createNotFoundDirectoryListener()
+
+  return function serveStatic (req, res, next) {
+    if (req.method !== 'GET' && req.method !== 'HEAD') {
+      if (fallthrough) {
+        return next()
+      }
+
+      // method not allowed
+      res.statusCode = 405
+      res.setHeader('Allow', 'GET, HEAD')
+      res.setHeader('Content-Length', '0')
+      res.end()
+      return
+    }
+
+    var forwardError = !fallthrough
+    var originalUrl = parseUrl.original(req)
+    var path = parseUrl(req).pathname
+
+    // make sure redirect occurs at mount
+    if (path === '/' && originalUrl.pathname.substr(-1) !== '/') {
+      path = ''
+    }
+
+    // create send stream
+    var stream = send(req, path, opts)
+
+    // add directory handler
+    stream.on('directory', onDirectory)
+
+    // add headers listener
+    if (setHeaders) {
+      stream.on('headers', setHeaders)
+    }
+
+    // add file listener for fallthrough
+    if (fallthrough) {
+      stream.on('file', function onFile () {
+        // once file is determined, always forward error
+        forwardError = true
+      })
+    }
+
+    // forward errors
+    stream.on('error', function error (err) {
+      if (forwardError || !(err.statusCode < 500)) {
+        next(err)
+        return
+      }
+
+      next()
+    })
+
+    // pipe
+    stream.pipe(res)
+  }
+}
+
+/**
+ * Collapse all leading slashes into a single slash
+ * @private
+ */
+function collapseLeadingSlashes (str) {
+  for (var i = 0; i < str.length; i++) {
+    if (str.charCodeAt(i) !== 0x2f /* / */) {
+      break
+    }
+  }
+
+  return i > 1
+    ? '/' + str.substr(i)
+    : str
+}
+
+/**
+ * Create a minimal HTML document.
+ *
+ * @param {string} title
+ * @param {string} body
+ * @private
+ */
+
+function createHtmlDocument (title, body) {
+  return '<!DOCTYPE html>\n' +
+    '<html lang="en">\n' +
+    '<head>\n' +
+    '<meta charset="utf-8">\n' +
+    '<title>' + title + '</title>\n' +
+    '</head>\n' +
+    '<body>\n' +
+    '<pre>' + body + '</pre>\n' +
+    '</body>\n' +
+    '</html>\n'
+}
+
+/**
+ * Create a directory listener that just 404s.
+ * @private
+ */
+
+function createNotFoundDirectoryListener () {
+  return function notFound () {
+    this.error(404)
+  }
+}
+
+/**
+ * Create a directory listener that performs a redirect.
+ * @private
+ */
+
+function createRedirectDirectoryListener () {
+  return function redirect (res) {
+    if (this.hasTrailingSlash()) {
+      this.error(404)
+      return
+    }
+
+    // get original URL
+    var originalUrl = parseUrl.original(this.req)
+
+    // append trailing slash
+    originalUrl.path = null
+    originalUrl.pathname = collapseLeadingSlashes(originalUrl.pathname + '/')
+
+    // reformat the URL
+    var loc = encodeUrl(url.format(originalUrl))
+    var doc = createHtmlDocument('Redirecting', 'Redirecting to ' + escapeHtml(loc))
+
+    // send redirect response
+    res.statusCode = 301
+    res.setHeader('Content-Type', 'text/html; charset=UTF-8')
+    res.setHeader('Content-Length', Buffer.byteLength(doc))
+    res.setHeader('Content-Security-Policy', "default-src 'none'")
+    res.setHeader('X-Content-Type-Options', 'nosniff')
+    res.setHeader('Location', loc)
+    res.end(doc)
+  }
+}
diff --git a/server/node_modules/serve-static/package.json b/server/node_modules/serve-static/package.json
new file mode 100644
index 0000000..b268e48
--- /dev/null
+++ b/server/node_modules/serve-static/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "serve-static",
+  "description": "Serve static files",
+  "version": "1.16.3",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "repository": "expressjs/serve-static",
+  "dependencies": {
+    "encodeurl": "~2.0.0",
+    "escape-html": "~1.0.3",
+    "parseurl": "~1.3.3",
+    "send": "~0.19.1"
+  },
+  "devDependencies": {
+    "eslint": "7.32.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.25.4",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "5.2.0",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "9.2.2",
+    "nyc": "15.1.0",
+    "safe-buffer": "5.2.1",
+    "supertest": "6.2.2"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8.0"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  }
+}
diff --git a/server/node_modules/set-blocking/CHANGELOG.md b/server/node_modules/set-blocking/CHANGELOG.md
new file mode 100644
index 0000000..03bf591
--- /dev/null
+++ b/server/node_modules/set-blocking/CHANGELOG.md
@@ -0,0 +1,26 @@
+# Change Log
+
+All notable changes to this project will be documented in this file. See [standard-version](https://github.com/conventional-changelog/standard-version) for commit guidelines.
+
+<a name="2.0.0"></a>
+# [2.0.0](https://github.com/yargs/set-blocking/compare/v1.0.0...v2.0.0) (2016-05-17)
+
+
+### Features
+
+* add an isTTY check ([#3](https://github.com/yargs/set-blocking/issues/3)) ([66ce277](https://github.com/yargs/set-blocking/commit/66ce277))
+
+
+### BREAKING CHANGES
+
+* stdio/stderr will not be set to blocking if isTTY === false
+
+
+
+<a name="1.0.0"></a>
+# 1.0.0 (2016-05-14)
+
+
+### Features
+
+* implemented shim for stream._handle.setBlocking ([6bde0c0](https://github.com/yargs/set-blocking/commit/6bde0c0))
diff --git a/server/node_modules/set-blocking/LICENSE.txt b/server/node_modules/set-blocking/LICENSE.txt
new file mode 100644
index 0000000..836440b
--- /dev/null
+++ b/server/node_modules/set-blocking/LICENSE.txt
@@ -0,0 +1,14 @@
+Copyright (c) 2016, Contributors
+
+Permission to use, copy, modify, and/or distribute this software
+for any purpose with or without fee is hereby granted, provided
+that the above copyright notice and this permission notice
+appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE
+LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
+OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/set-blocking/README.md b/server/node_modules/set-blocking/README.md
new file mode 100644
index 0000000..e93b420
--- /dev/null
+++ b/server/node_modules/set-blocking/README.md
@@ -0,0 +1,31 @@
+# set-blocking
+
+[![Build Status](https://travis-ci.org/yargs/set-blocking.svg)](https://travis-ci.org/yargs/set-blocking)
+[![NPM version](https://img.shields.io/npm/v/set-blocking.svg)](https://www.npmjs.com/package/set-blocking)
+[![Coverage Status](https://coveralls.io/repos/yargs/set-blocking/badge.svg?branch=)](https://coveralls.io/r/yargs/set-blocking?branch=master)
+[![Standard Version](https://img.shields.io/badge/release-standard%20version-brightgreen.svg)](https://github.com/conventional-changelog/standard-version)
+
+set blocking `stdio` and `stderr` ensuring that terminal output does not truncate.
+
+```js
+const setBlocking = require('set-blocking')
+setBlocking(true)
+console.log(someLargeStringToOutput)
+```
+
+## Historical Context/Word of Warning
+
+This was created as a shim to address the bug discussed in [node #6456](https://github.com/nodejs/node/issues/6456). This bug crops up on
+newer versions of Node.js (`0.12+`), truncating terminal output.
+
+You should be mindful of the side-effects caused by using `set-blocking`:
+
+* if your module sets blocking to `true`, it will effect other modules
+  consuming your library. In [yargs](https://github.com/yargs/yargs/blob/master/yargs.js#L653) we only call
+  `setBlocking(true)` once we already know we are about to call `process.exit(code)`.
+* this patch will not apply to subprocesses spawned with `isTTY = true`, this is
+  the [default `spawn()` behavior](https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options).
+
+## License
+
+ISC
diff --git a/server/node_modules/set-blocking/index.js b/server/node_modules/set-blocking/index.js
new file mode 100644
index 0000000..6f78774
--- /dev/null
+++ b/server/node_modules/set-blocking/index.js
@@ -0,0 +1,7 @@
+module.exports = function (blocking) {
+  [process.stdout, process.stderr].forEach(function (stream) {
+    if (stream._handle && stream.isTTY && typeof stream._handle.setBlocking === 'function') {
+      stream._handle.setBlocking(blocking)
+    }
+  })
+}
diff --git a/server/node_modules/set-blocking/package.json b/server/node_modules/set-blocking/package.json
new file mode 100644
index 0000000..c082db7
--- /dev/null
+++ b/server/node_modules/set-blocking/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "set-blocking",
+  "version": "2.0.0",
+  "description": "set blocking stdio and stderr ensuring that terminal output does not truncate",
+  "main": "index.js",
+  "scripts": {
+    "pretest": "standard",
+    "test": "nyc mocha ./test/*.js",
+    "coverage": "nyc report --reporter=text-lcov | coveralls",
+    "version": "standard-version"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/yargs/set-blocking.git"
+  },
+  "keywords": [
+    "flush",
+    "terminal",
+    "blocking",
+    "shim",
+    "stdio",
+    "stderr"
+  ],
+  "author": "Ben Coe <ben@npmjs.com>",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/yargs/set-blocking/issues"
+  },
+  "homepage": "https://github.com/yargs/set-blocking#readme",
+  "devDependencies": {
+    "chai": "^3.5.0",
+    "coveralls": "^2.11.9",
+    "mocha": "^2.4.5",
+    "nyc": "^6.4.4",
+    "standard": "^7.0.1",
+    "standard-version": "^2.2.1"
+  },
+  "files": [
+    "index.js",
+    "LICENSE.txt"
+  ]
+}
\ No newline at end of file
diff --git a/server/node_modules/setprototypeof/LICENSE b/server/node_modules/setprototypeof/LICENSE
new file mode 100644
index 0000000..61afa2f
--- /dev/null
+++ b/server/node_modules/setprototypeof/LICENSE
@@ -0,0 +1,13 @@
+Copyright (c) 2015, Wes Todd
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/setprototypeof/README.md b/server/node_modules/setprototypeof/README.md
new file mode 100644
index 0000000..791eeff
--- /dev/null
+++ b/server/node_modules/setprototypeof/README.md
@@ -0,0 +1,31 @@
+# Polyfill for `Object.setPrototypeOf`
+
+[![NPM Version](https://img.shields.io/npm/v/setprototypeof.svg)](https://npmjs.org/package/setprototypeof)
+[![NPM Downloads](https://img.shields.io/npm/dm/setprototypeof.svg)](https://npmjs.org/package/setprototypeof)
+[![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg)](https://github.com/standard/standard)
+
+A simple cross platform implementation to set the prototype of an instianted object.  Supports all modern browsers and at least back to IE8.
+
+## Usage:
+
+```
+$ npm install --save setprototypeof
+```
+
+```javascript
+var setPrototypeOf = require('setprototypeof')
+
+var obj = {}
+setPrototypeOf(obj, {
+  foo: function () {
+    return 'bar'
+  }
+})
+obj.foo() // bar
+```
+
+TypeScript is also supported:
+
+```typescript
+import setPrototypeOf from 'setprototypeof'
+```
diff --git a/server/node_modules/setprototypeof/index.d.ts b/server/node_modules/setprototypeof/index.d.ts
new file mode 100644
index 0000000..f108ecd
--- /dev/null
+++ b/server/node_modules/setprototypeof/index.d.ts
@@ -0,0 +1,2 @@
+declare function setPrototypeOf(o: any, proto: object | null): any;
+export = setPrototypeOf;
diff --git a/server/node_modules/setprototypeof/index.js b/server/node_modules/setprototypeof/index.js
new file mode 100644
index 0000000..c527055
--- /dev/null
+++ b/server/node_modules/setprototypeof/index.js
@@ -0,0 +1,17 @@
+'use strict'
+/* eslint no-proto: 0 */
+module.exports = Object.setPrototypeOf || ({ __proto__: [] } instanceof Array ? setProtoOf : mixinProperties)
+
+function setProtoOf (obj, proto) {
+  obj.__proto__ = proto
+  return obj
+}
+
+function mixinProperties (obj, proto) {
+  for (var prop in proto) {
+    if (!Object.prototype.hasOwnProperty.call(obj, prop)) {
+      obj[prop] = proto[prop]
+    }
+  }
+  return obj
+}
diff --git a/server/node_modules/setprototypeof/package.json b/server/node_modules/setprototypeof/package.json
new file mode 100644
index 0000000..f20915b
--- /dev/null
+++ b/server/node_modules/setprototypeof/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "setprototypeof",
+  "version": "1.2.0",
+  "description": "A small polyfill for Object.setprototypeof",
+  "main": "index.js",
+  "typings": "index.d.ts",
+  "scripts": {
+    "test": "standard && mocha",
+    "testallversions": "npm run node010 && npm run node4 && npm run node6 && npm run node9 && npm run node11",
+    "testversion": "docker run -it --rm -v $(PWD):/usr/src/app -w /usr/src/app node:${NODE_VER} npm install mocha@${MOCHA_VER:-latest} && npm t",
+    "node010": "NODE_VER=0.10 MOCHA_VER=3 npm run testversion",
+    "node4": "NODE_VER=4 npm run testversion",
+    "node6": "NODE_VER=6 npm run testversion",
+    "node9": "NODE_VER=9 npm run testversion",
+    "node11": "NODE_VER=11 npm run testversion",
+    "prepublishOnly": "npm t",
+    "postpublish": "git push origin && git push origin --tags"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/wesleytodd/setprototypeof.git"
+  },
+  "keywords": [
+    "polyfill",
+    "object",
+    "setprototypeof"
+  ],
+  "author": "Wes Todd",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/wesleytodd/setprototypeof/issues"
+  },
+  "homepage": "https://github.com/wesleytodd/setprototypeof",
+  "devDependencies": {
+    "mocha": "^6.1.4",
+    "standard": "^13.0.2"
+  }
+}
diff --git a/server/node_modules/setprototypeof/test/index.js b/server/node_modules/setprototypeof/test/index.js
new file mode 100644
index 0000000..afeb4dd
--- /dev/null
+++ b/server/node_modules/setprototypeof/test/index.js
@@ -0,0 +1,24 @@
+'use strict'
+/* eslint-env mocha */
+/* eslint no-proto: 0 */
+var assert = require('assert')
+var setPrototypeOf = require('..')
+
+describe('setProtoOf(obj, proto)', function () {
+  it('should merge objects', function () {
+    var obj = { a: 1, b: 2 }
+    var proto = { b: 3, c: 4 }
+    var mergeObj = setPrototypeOf(obj, proto)
+
+    if (Object.getPrototypeOf) {
+      assert.strictEqual(Object.getPrototypeOf(obj), proto)
+    } else if ({ __proto__: [] } instanceof Array) {
+      assert.strictEqual(obj.__proto__, proto)
+    } else {
+      assert.strictEqual(obj.a, 1)
+      assert.strictEqual(obj.b, 2)
+      assert.strictEqual(obj.c, 4)
+    }
+    assert.strictEqual(mergeObj, obj)
+  })
+})
diff --git a/server/node_modules/side-channel-list/.editorconfig b/server/node_modules/side-channel-list/.editorconfig
new file mode 100644
index 0000000..72e0eba
--- /dev/null
+++ b/server/node_modules/side-channel-list/.editorconfig
@@ -0,0 +1,9 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = tab
+indent_size = 2
+trim_trailing_whitespace = true
diff --git a/server/node_modules/side-channel-list/.eslintrc b/server/node_modules/side-channel-list/.eslintrc
new file mode 100644
index 0000000..93978e7
--- /dev/null
+++ b/server/node_modules/side-channel-list/.eslintrc
@@ -0,0 +1,11 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"max-lines-per-function": 0,
+		"multiline-comment-style": 1,
+		"new-cap": [2, { "capIsNewExceptions": ["GetIntrinsic"] }],
+	},
+}
diff --git a/server/node_modules/side-channel-list/.github/FUNDING.yml b/server/node_modules/side-channel-list/.github/FUNDING.yml
new file mode 100644
index 0000000..eaff735
--- /dev/null
+++ b/server/node_modules/side-channel-list/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/side-channel-list
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/side-channel-list/.nycrc b/server/node_modules/side-channel-list/.nycrc
new file mode 100644
index 0000000..1826526
--- /dev/null
+++ b/server/node_modules/side-channel-list/.nycrc
@@ -0,0 +1,13 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"lines": 86,
+	"statements": 85.93,
+	"functions": 82.43,
+	"branches": 76.06,
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/side-channel-list/CHANGELOG.md b/server/node_modules/side-channel-list/CHANGELOG.md
new file mode 100644
index 0000000..2ec51b7
--- /dev/null
+++ b/server/node_modules/side-channel-list/CHANGELOG.md
@@ -0,0 +1,15 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## v1.0.0 - 2024-12-10
+
+### Commits
+
+- Initial implementation, tests, readme, types [`5d6baee`](https://github.com/ljharb/side-channel-list/commit/5d6baee5c9054a1238007f5a1dfc109a7a816251)
+- Initial commit [`3ae784c`](https://github.com/ljharb/side-channel-list/commit/3ae784c63a47895fbaeed2a91ab54a8029a7a100)
+- npm init [`07055a4`](https://github.com/ljharb/side-channel-list/commit/07055a4d139895565b199dba5fe2479c1a1b9e28)
+- Only apps should have lockfiles [`9573058`](https://github.com/ljharb/side-channel-list/commit/9573058a47494e2d68f8c6c77b5d7fbe441949c1)
diff --git a/server/node_modules/side-channel-list/LICENSE b/server/node_modules/side-channel-list/LICENSE
new file mode 100644
index 0000000..f82f389
--- /dev/null
+++ b/server/node_modules/side-channel-list/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/side-channel-list/README.md b/server/node_modules/side-channel-list/README.md
new file mode 100644
index 0000000..d9c7a13
--- /dev/null
+++ b/server/node_modules/side-channel-list/README.md
@@ -0,0 +1,62 @@
+# side-channel-list <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+Store information about any JS value in a side channel, using a linked list.
+
+Warning: this implementation will leak memory until you `delete` the `key`.
+Use [`side-channel`](https://npmjs.com/side-channel) for the best available strategy.
+
+## Getting started
+
+```sh
+npm install --save side-channel-list
+```
+
+## Usage/Examples
+
+```js
+const assert = require('assert');
+const getSideChannelList = require('side-channel-list');
+
+const channel = getSideChannelList();
+
+const key = {};
+assert.equal(channel.has(key), false);
+assert.throws(() => channel.assert(key), TypeError);
+
+channel.set(key, 42);
+
+channel.assert(key); // does not throw
+assert.equal(channel.has(key), true);
+assert.equal(channel.get(key), 42);
+
+channel.delete(key);
+assert.equal(channel.has(key), false);
+assert.throws(() => channel.assert(key), TypeError);
+```
+
+## Tests
+
+Clone the repo, `npm install`, and run `npm test`
+
+[package-url]: https://npmjs.org/package/side-channel-list
+[npm-version-svg]: https://versionbadg.es/ljharb/side-channel-list.svg
+[deps-svg]: https://david-dm.org/ljharb/side-channel-list.svg
+[deps-url]: https://david-dm.org/ljharb/side-channel-list
+[dev-deps-svg]: https://david-dm.org/ljharb/side-channel-list/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/side-channel-list#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/side-channel-list.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/side-channel-list.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/side-channel-list.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=side-channel-list
+[codecov-image]: https://codecov.io/gh/ljharb/side-channel-list/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/side-channel-list/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/side-channel-list
+[actions-url]: https://github.com/ljharb/side-channel-list/actions
diff --git a/server/node_modules/side-channel-list/index.d.ts b/server/node_modules/side-channel-list/index.d.ts
new file mode 100644
index 0000000..c9cabc8
--- /dev/null
+++ b/server/node_modules/side-channel-list/index.d.ts
@@ -0,0 +1,13 @@
+declare namespace getSideChannelList {
+	type Channel<K, V> = {
+		assert: (key: K) => void;
+		has: (key: K) => boolean;
+		get: (key: K) => V | undefined;
+		set: (key: K, value: V) => void;
+		delete: (key: K) => boolean;
+	};
+}
+
+declare function getSideChannelList<V, K>(): getSideChannelList.Channel<K, V>;
+
+export = getSideChannelList;
diff --git a/server/node_modules/side-channel-list/index.js b/server/node_modules/side-channel-list/index.js
new file mode 100644
index 0000000..8d6f98c
--- /dev/null
+++ b/server/node_modules/side-channel-list/index.js
@@ -0,0 +1,113 @@
+'use strict';
+
+var inspect = require('object-inspect');
+
+var $TypeError = require('es-errors/type');
+
+/*
+* This function traverses the list returning the node corresponding to the given key.
+*
+* That node is also moved to the head of the list, so that if it's accessed again we don't need to traverse the whole list.
+* By doing so, all the recently used nodes can be accessed relatively quickly.
+*/
+/** @type {import('./list.d.ts').listGetNode} */
+// eslint-disable-next-line consistent-return
+var listGetNode = function (list, key, isDelete) {
+	/** @type {typeof list | NonNullable<(typeof list)['next']>} */
+	var prev = list;
+	/** @type {(typeof list)['next']} */
+	var curr;
+	// eslint-disable-next-line eqeqeq
+	for (; (curr = prev.next) != null; prev = curr) {
+		if (curr.key === key) {
+			prev.next = curr.next;
+			if (!isDelete) {
+				// eslint-disable-next-line no-extra-parens
+				curr.next = /** @type {NonNullable<typeof list.next>} */ (list.next);
+				list.next = curr; // eslint-disable-line no-param-reassign
+			}
+			return curr;
+		}
+	}
+};
+
+/** @type {import('./list.d.ts').listGet} */
+var listGet = function (objects, key) {
+	if (!objects) {
+		return void undefined;
+	}
+	var node = listGetNode(objects, key);
+	return node && node.value;
+};
+/** @type {import('./list.d.ts').listSet} */
+var listSet = function (objects, key, value) {
+	var node = listGetNode(objects, key);
+	if (node) {
+		node.value = value;
+	} else {
+		// Prepend the new node to the beginning of the list
+		objects.next = /** @type {import('./list.d.ts').ListNode<typeof value, typeof key>} */ ({ // eslint-disable-line no-param-reassign, no-extra-parens
+			key: key,
+			next: objects.next,
+			value: value
+		});
+	}
+};
+/** @type {import('./list.d.ts').listHas} */
+var listHas = function (objects, key) {
+	if (!objects) {
+		return false;
+	}
+	return !!listGetNode(objects, key);
+};
+/** @type {import('./list.d.ts').listDelete} */
+// eslint-disable-next-line consistent-return
+var listDelete = function (objects, key) {
+	if (objects) {
+		return listGetNode(objects, key, true);
+	}
+};
+
+/** @type {import('.')} */
+module.exports = function getSideChannelList() {
+	/** @typedef {ReturnType<typeof getSideChannelList>} Channel */
+	/** @typedef {Parameters<Channel['get']>[0]} K */
+	/** @typedef {Parameters<Channel['set']>[1]} V */
+
+	/** @type {import('./list.d.ts').RootNode<V, K> | undefined} */ var $o;
+
+	/** @type {Channel} */
+	var channel = {
+		assert: function (key) {
+			if (!channel.has(key)) {
+				throw new $TypeError('Side channel does not contain ' + inspect(key));
+			}
+		},
+		'delete': function (key) {
+			var root = $o && $o.next;
+			var deletedNode = listDelete($o, key);
+			if (deletedNode && root && root === deletedNode) {
+				$o = void undefined;
+			}
+			return !!deletedNode;
+		},
+		get: function (key) {
+			return listGet($o, key);
+		},
+		has: function (key) {
+			return listHas($o, key);
+		},
+		set: function (key, value) {
+			if (!$o) {
+				// Initialize the linked list as an empty node, so that we don't have to special-case handling of the first node: we can always refer to it as (previous node).next, instead of something like (list).head
+				$o = {
+					next: void undefined
+				};
+			}
+			// eslint-disable-next-line no-extra-parens
+			listSet(/** @type {NonNullable<typeof $o>} */ ($o), key, value);
+		}
+	};
+	// @ts-expect-error TODO: figure out why this is erroring
+	return channel;
+};
diff --git a/server/node_modules/side-channel-list/list.d.ts b/server/node_modules/side-channel-list/list.d.ts
new file mode 100644
index 0000000..2c759e2
--- /dev/null
+++ b/server/node_modules/side-channel-list/list.d.ts
@@ -0,0 +1,14 @@
+type ListNode<T, K> = {
+	key: K;
+	next: undefined | ListNode<T, K>;
+	value: T;
+};
+type RootNode<T, K> = {
+	next: undefined | ListNode<T, K>;
+};
+
+export function listGetNode<T, K>(list: RootNode<T, K>, key: ListNode<T, K>['key'], isDelete?: boolean): ListNode<T, K> | undefined;
+export function listGet<T, K>(objects: undefined | RootNode<T, K>, key: ListNode<T, K>['key']): T | undefined;
+export function listSet<T, K>(objects: RootNode<T, K>, key: ListNode<T, K>['key'], value: T): void;
+export function listHas<T, K>(objects: undefined | RootNode<T, K>, key: ListNode<T, K>['key']): boolean;
+export function listDelete<T, K>(objects: undefined | RootNode<T, K>, key: ListNode<T, K>['key']): ListNode<T, K> | undefined;
diff --git a/server/node_modules/side-channel-list/package.json b/server/node_modules/side-channel-list/package.json
new file mode 100644
index 0000000..ba0f5c5
--- /dev/null
+++ b/server/node_modules/side-channel-list/package.json
@@ -0,0 +1,77 @@
+{
+	"name": "side-channel-list",
+	"version": "1.0.0",
+	"description": "Store information about any JS value in a side channel, using a linked list",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./package.json": "./package.json"
+	},
+	"types": "./index.d.ts",
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prelint": "evalmd README.md && eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git')",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc -p . && attw -P",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>= 10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/side-channel-list.git"
+	},
+	"keywords": [],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"funding": {
+		"url": "https://github.com/sponsors/ljharb"
+	},
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/side-channel-list/issues"
+	},
+	"homepage": "https://github.com/ljharb/side-channel-list#readme",
+	"dependencies": {
+		"es-errors": "^1.3.0",
+		"object-inspect": "^1.13.3"
+	},
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.1",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.2",
+		"@types/object-inspect": "^1.13.0",
+		"@types/tape": "^5.6.5",
+		"auto-changelog": "^2.5.0",
+		"eclint": "^2.8.1",
+		"encoding": "^0.1.13",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/side-channel-list/test/index.js b/server/node_modules/side-channel-list/test/index.js
new file mode 100644
index 0000000..3ad4368
--- /dev/null
+++ b/server/node_modules/side-channel-list/test/index.js
@@ -0,0 +1,104 @@
+'use strict';
+
+var test = require('tape');
+
+var getSideChannelList = require('../');
+
+test('getSideChannelList', function (t) {
+	t.test('export', function (st) {
+		st.equal(typeof getSideChannelList, 'function', 'is a function');
+
+		st.equal(getSideChannelList.length, 0, 'takes no arguments');
+
+		var channel = getSideChannelList();
+		st.ok(channel, 'is truthy');
+		st.equal(typeof channel, 'object', 'is an object');
+		st.end();
+	});
+
+	t.test('assert', function (st) {
+		var channel = getSideChannelList();
+		st['throws'](
+			function () { channel.assert({}); },
+			TypeError,
+			'nonexistent value throws'
+		);
+
+		var o = {};
+		channel.set(o, 'data');
+		st.doesNotThrow(function () { channel.assert(o); }, 'existent value noops');
+
+		st.end();
+	});
+
+	t.test('has', function (st) {
+		var channel = getSideChannelList();
+		/** @type {unknown[]} */ var o = [];
+
+		st.equal(channel.has(o), false, 'nonexistent value yields false');
+
+		channel.set(o, 'foo');
+		st.equal(channel.has(o), true, 'existent value yields true');
+
+		st.equal(channel.has('abc'), false, 'non object value non existent yields false');
+
+		channel.set('abc', 'foo');
+		st.equal(channel.has('abc'), true, 'non object value that exists yields true');
+
+		st.end();
+	});
+
+	t.test('get', function (st) {
+		var channel = getSideChannelList();
+		var o = {};
+		st.equal(channel.get(o), undefined, 'nonexistent value yields undefined');
+
+		var data = {};
+		channel.set(o, data);
+		st.equal(channel.get(o), data, '"get" yields data set by "set"');
+
+		st.end();
+	});
+
+	t.test('set', function (st) {
+		var channel = getSideChannelList();
+		var o = function () {};
+		st.equal(channel.get(o), undefined, 'value not set');
+
+		channel.set(o, 42);
+		st.equal(channel.get(o), 42, 'value was set');
+
+		channel.set(o, Infinity);
+		st.equal(channel.get(o), Infinity, 'value was set again');
+
+		var o2 = {};
+		channel.set(o2, 17);
+		st.equal(channel.get(o), Infinity, 'o is not modified');
+		st.equal(channel.get(o2), 17, 'o2 is set');
+
+		channel.set(o, 14);
+		st.equal(channel.get(o), 14, 'o is modified');
+		st.equal(channel.get(o2), 17, 'o2 is not modified');
+
+		st.end();
+	});
+
+	t.test('delete', function (st) {
+		var channel = getSideChannelList();
+		var o = {};
+		st.equal(channel['delete']({}), false, 'nonexistent value yields false');
+
+		channel.set(o, 42);
+		st.equal(channel.has(o), true, 'value is set');
+
+		st.equal(channel['delete']({}), false, 'nonexistent value still yields false');
+
+		st.equal(channel['delete'](o), true, 'deleted value yields true');
+
+		st.equal(channel.has(o), false, 'value is no longer set');
+
+		st.end();
+	});
+
+	t.end();
+});
diff --git a/server/node_modules/side-channel-list/tsconfig.json b/server/node_modules/side-channel-list/tsconfig.json
new file mode 100644
index 0000000..d9a6668
--- /dev/null
+++ b/server/node_modules/side-channel-list/tsconfig.json
@@ -0,0 +1,9 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "es2021",
+	},
+	"exclude": [
+		"coverage",
+	],
+}
diff --git a/server/node_modules/side-channel-map/.editorconfig b/server/node_modules/side-channel-map/.editorconfig
new file mode 100644
index 0000000..72e0eba
--- /dev/null
+++ b/server/node_modules/side-channel-map/.editorconfig
@@ -0,0 +1,9 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = tab
+indent_size = 2
+trim_trailing_whitespace = true
diff --git a/server/node_modules/side-channel-map/.eslintrc b/server/node_modules/side-channel-map/.eslintrc
new file mode 100644
index 0000000..93978e7
--- /dev/null
+++ b/server/node_modules/side-channel-map/.eslintrc
@@ -0,0 +1,11 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"max-lines-per-function": 0,
+		"multiline-comment-style": 1,
+		"new-cap": [2, { "capIsNewExceptions": ["GetIntrinsic"] }],
+	},
+}
diff --git a/server/node_modules/side-channel-map/.github/FUNDING.yml b/server/node_modules/side-channel-map/.github/FUNDING.yml
new file mode 100644
index 0000000..f2891bd
--- /dev/null
+++ b/server/node_modules/side-channel-map/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/side-channel-map
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/side-channel-map/.nycrc b/server/node_modules/side-channel-map/.nycrc
new file mode 100644
index 0000000..1826526
--- /dev/null
+++ b/server/node_modules/side-channel-map/.nycrc
@@ -0,0 +1,13 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"lines": 86,
+	"statements": 85.93,
+	"functions": 82.43,
+	"branches": 76.06,
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/side-channel-map/CHANGELOG.md b/server/node_modules/side-channel-map/CHANGELOG.md
new file mode 100644
index 0000000..b6ccea9
--- /dev/null
+++ b/server/node_modules/side-channel-map/CHANGELOG.md
@@ -0,0 +1,22 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.0.1](https://github.com/ljharb/side-channel-map/compare/v1.0.0...v1.0.1) - 2024-12-10
+
+### Commits
+
+- [Deps] update `call-bound` [`6d05aaa`](https://github.com/ljharb/side-channel-map/commit/6d05aaa4ce5f2be4e7825df433d650696f0ba40f)
+- [types] fix generics ordering [`11c0184`](https://github.com/ljharb/side-channel-map/commit/11c0184132ac11fdc16857e12682e148e5e9ee74)
+
+## v1.0.0 - 2024-12-10
+
+### Commits
+
+- Initial implementation, tests, readme, types [`ad877b4`](https://github.com/ljharb/side-channel-map/commit/ad877b42926d46d63fff76a2bd01d2b4a01959a9)
+- Initial commit [`28f8879`](https://github.com/ljharb/side-channel-map/commit/28f8879c512abe8fcf9b6a4dc7754a0287e5eba4)
+- npm init [`2c9604e`](https://github.com/ljharb/side-channel-map/commit/2c9604e5aa40223e425ea7cea78f8a07697504bd)
+- Only apps should have lockfiles [`5e7ba9c`](https://github.com/ljharb/side-channel-map/commit/5e7ba9cffe3ef42095815adc8ac1255b49bbadf5)
diff --git a/server/node_modules/side-channel-map/LICENSE b/server/node_modules/side-channel-map/LICENSE
new file mode 100644
index 0000000..f82f389
--- /dev/null
+++ b/server/node_modules/side-channel-map/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/side-channel-map/README.md b/server/node_modules/side-channel-map/README.md
new file mode 100644
index 0000000..8fa6f77
--- /dev/null
+++ b/server/node_modules/side-channel-map/README.md
@@ -0,0 +1,62 @@
+# side-channel-map <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+Store information about any JS value in a side channel, using a Map.
+
+Warning: if the `key` is an object, this implementation will leak memory until you `delete` it.
+Use [`side-channel`](https://npmjs.com/side-channel) for the best available strategy.
+
+## Getting started
+
+```sh
+npm install --save side-channel-map
+```
+
+## Usage/Examples
+
+```js
+const assert = require('assert');
+const getSideChannelMap = require('side-channel-map');
+
+const channel = getSideChannelMap();
+
+const key = {};
+assert.equal(channel.has(key), false);
+assert.throws(() => channel.assert(key), TypeError);
+
+channel.set(key, 42);
+
+channel.assert(key); // does not throw
+assert.equal(channel.has(key), true);
+assert.equal(channel.get(key), 42);
+
+channel.delete(key);
+assert.equal(channel.has(key), false);
+assert.throws(() => channel.assert(key), TypeError);
+```
+
+## Tests
+
+Clone the repo, `npm install`, and run `npm test`
+
+[package-url]: https://npmjs.org/package/side-channel-map
+[npm-version-svg]: https://versionbadg.es/ljharb/side-channel-map.svg
+[deps-svg]: https://david-dm.org/ljharb/side-channel-map.svg
+[deps-url]: https://david-dm.org/ljharb/side-channel-map
+[dev-deps-svg]: https://david-dm.org/ljharb/side-channel-map/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/side-channel-map#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/side-channel-map.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/side-channel-map.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/side-channel-map.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=side-channel-map
+[codecov-image]: https://codecov.io/gh/ljharb/side-channel-map/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/side-channel-map/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/side-channel-map
+[actions-url]: https://github.com/ljharb/side-channel-map/actions
diff --git a/server/node_modules/side-channel-map/index.d.ts b/server/node_modules/side-channel-map/index.d.ts
new file mode 100644
index 0000000..de33e89
--- /dev/null
+++ b/server/node_modules/side-channel-map/index.d.ts
@@ -0,0 +1,15 @@
+declare namespace getSideChannelMap {
+	type Channel<K, V> = {
+		assert: (key: K) => void;
+		has: (key: K) => boolean;
+		get: (key: K) => V | undefined;
+		set: (key: K, value: V) => void;
+		delete: (key: K) => boolean;
+	};
+}
+
+declare function getSideChannelMap<K, V>(): getSideChannelMap.Channel<K, V>;
+
+declare const x: false | typeof getSideChannelMap;
+
+export = x;
diff --git a/server/node_modules/side-channel-map/index.js b/server/node_modules/side-channel-map/index.js
new file mode 100644
index 0000000..e111100
--- /dev/null
+++ b/server/node_modules/side-channel-map/index.js
@@ -0,0 +1,68 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+var callBound = require('call-bound');
+var inspect = require('object-inspect');
+
+var $TypeError = require('es-errors/type');
+var $Map = GetIntrinsic('%Map%', true);
+
+/** @type {<K, V>(thisArg: Map<K, V>, key: K) => V} */
+var $mapGet = callBound('Map.prototype.get', true);
+/** @type {<K, V>(thisArg: Map<K, V>, key: K, value: V) => void} */
+var $mapSet = callBound('Map.prototype.set', true);
+/** @type {<K, V>(thisArg: Map<K, V>, key: K) => boolean} */
+var $mapHas = callBound('Map.prototype.has', true);
+/** @type {<K, V>(thisArg: Map<K, V>, key: K) => boolean} */
+var $mapDelete = callBound('Map.prototype.delete', true);
+/** @type {<K, V>(thisArg: Map<K, V>) => number} */
+var $mapSize = callBound('Map.prototype.size', true);
+
+/** @type {import('.')} */
+module.exports = !!$Map && /** @type {Exclude<import('.'), false>} */ function getSideChannelMap() {
+	/** @typedef {ReturnType<typeof getSideChannelMap>} Channel */
+	/** @typedef {Parameters<Channel['get']>[0]} K */
+	/** @typedef {Parameters<Channel['set']>[1]} V */
+
+	/** @type {Map<K, V> | undefined} */ var $m;
+
+	/** @type {Channel} */
+	var channel = {
+		assert: function (key) {
+			if (!channel.has(key)) {
+				throw new $TypeError('Side channel does not contain ' + inspect(key));
+			}
+		},
+		'delete': function (key) {
+			if ($m) {
+				var result = $mapDelete($m, key);
+				if ($mapSize($m) === 0) {
+					$m = void undefined;
+				}
+				return result;
+			}
+			return false;
+		},
+		get: function (key) { // eslint-disable-line consistent-return
+			if ($m) {
+				return $mapGet($m, key);
+			}
+		},
+		has: function (key) {
+			if ($m) {
+				return $mapHas($m, key);
+			}
+			return false;
+		},
+		set: function (key, value) {
+			if (!$m) {
+				// @ts-expect-error TS can't handle narrowing a variable inside a closure
+				$m = new $Map();
+			}
+			$mapSet($m, key, value);
+		}
+	};
+
+	// @ts-expect-error TODO: figure out why TS is erroring here
+	return channel;
+};
diff --git a/server/node_modules/side-channel-map/package.json b/server/node_modules/side-channel-map/package.json
new file mode 100644
index 0000000..18e8080
--- /dev/null
+++ b/server/node_modules/side-channel-map/package.json
@@ -0,0 +1,80 @@
+{
+	"name": "side-channel-map",
+	"version": "1.0.1",
+	"description": "Store information about any JS value in a side channel, using a Map",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./package.json": "./package.json"
+	},
+	"types": "./index.d.ts",
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prelint": "evalmd README.md && eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git')",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc -p . && attw -P",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>= 10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/side-channel-map.git"
+	},
+	"keywords": [],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"funding": {
+		"url": "https://github.com/sponsors/ljharb"
+	},
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/side-channel-map/issues"
+	},
+	"homepage": "https://github.com/ljharb/side-channel-map#readme",
+	"dependencies": {
+		"call-bound": "^1.0.2",
+		"es-errors": "^1.3.0",
+		"get-intrinsic": "^1.2.5",
+		"object-inspect": "^1.13.3"
+	},
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.1",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.2",
+		"@types/get-intrinsic": "^1.2.3",
+		"@types/object-inspect": "^1.13.0",
+		"@types/tape": "^5.6.5",
+		"auto-changelog": "^2.5.0",
+		"eclint": "^2.8.1",
+		"encoding": "^0.1.13",
+		"eslint": "=8.8.0",
+		"evalmd": "^0.0.19",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/side-channel-map/test/index.js b/server/node_modules/side-channel-map/test/index.js
new file mode 100644
index 0000000..1743323
--- /dev/null
+++ b/server/node_modules/side-channel-map/test/index.js
@@ -0,0 +1,114 @@
+'use strict';
+
+var test = require('tape');
+
+var getSideChannelMap = require('../');
+
+test('getSideChannelMap', { skip: typeof Map !== 'function' }, function (t) {
+	var getSideChannel = getSideChannelMap || function () {
+		throw new EvalError('should never happen');
+	};
+
+	t.test('export', function (st) {
+		st.equal(typeof getSideChannel, 'function', 'is a function');
+
+		st.equal(getSideChannel.length, 0, 'takes no arguments');
+
+		var channel = getSideChannel();
+		st.ok(channel, 'is truthy');
+		st.equal(typeof channel, 'object', 'is an object');
+		st.end();
+	});
+
+	t.test('assert', function (st) {
+		var channel = getSideChannel();
+		st['throws'](
+			function () { channel.assert({}); },
+			TypeError,
+			'nonexistent value throws'
+		);
+
+		var o = {};
+		channel.set(o, 'data');
+		st.doesNotThrow(function () { channel.assert(o); }, 'existent value noops');
+
+		st.end();
+	});
+
+	t.test('has', function (st) {
+		var channel = getSideChannel();
+		/** @type {unknown[]} */ var o = [];
+
+		st.equal(channel.has(o), false, 'nonexistent value yields false');
+
+		channel.set(o, 'foo');
+		st.equal(channel.has(o), true, 'existent value yields true');
+
+		st.equal(channel.has('abc'), false, 'non object value non existent yields false');
+
+		channel.set('abc', 'foo');
+		st.equal(channel.has('abc'), true, 'non object value that exists yields true');
+
+		st.end();
+	});
+
+	t.test('get', function (st) {
+		var channel = getSideChannel();
+		var o = {};
+		st.equal(channel.get(o), undefined, 'nonexistent value yields undefined');
+
+		var data = {};
+		channel.set(o, data);
+		st.equal(channel.get(o), data, '"get" yields data set by "set"');
+
+		st.end();
+	});
+
+	t.test('set', function (st) {
+		var channel = getSideChannel();
+		var o = function () {};
+		st.equal(channel.get(o), undefined, 'value not set');
+
+		channel.set(o, 42);
+		st.equal(channel.get(o), 42, 'value was set');
+
+		channel.set(o, Infinity);
+		st.equal(channel.get(o), Infinity, 'value was set again');
+
+		var o2 = {};
+		channel.set(o2, 17);
+		st.equal(channel.get(o), Infinity, 'o is not modified');
+		st.equal(channel.get(o2), 17, 'o2 is set');
+
+		channel.set(o, 14);
+		st.equal(channel.get(o), 14, 'o is modified');
+		st.equal(channel.get(o2), 17, 'o2 is not modified');
+
+		st.end();
+	});
+
+	t.test('delete', function (st) {
+		var channel = getSideChannel();
+		var o = {};
+		st.equal(channel['delete']({}), false, 'nonexistent value yields false');
+
+		channel.set(o, 42);
+		st.equal(channel.has(o), true, 'value is set');
+
+		st.equal(channel['delete']({}), false, 'nonexistent value still yields false');
+
+		st.equal(channel['delete'](o), true, 'deleted value yields true');
+
+		st.equal(channel.has(o), false, 'value is no longer set');
+
+		st.end();
+	});
+
+	t.end();
+});
+
+test('getSideChannelMap, no Maps', { skip: typeof Map === 'function' }, function (t) {
+	t.equal(getSideChannelMap, false, 'is false');
+
+	t.end();
+});
diff --git a/server/node_modules/side-channel-map/tsconfig.json b/server/node_modules/side-channel-map/tsconfig.json
new file mode 100644
index 0000000..d9a6668
--- /dev/null
+++ b/server/node_modules/side-channel-map/tsconfig.json
@@ -0,0 +1,9 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "es2021",
+	},
+	"exclude": [
+		"coverage",
+	],
+}
diff --git a/server/node_modules/side-channel-weakmap/.editorconfig b/server/node_modules/side-channel-weakmap/.editorconfig
new file mode 100644
index 0000000..72e0eba
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/.editorconfig
@@ -0,0 +1,9 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = tab
+indent_size = 2
+trim_trailing_whitespace = true
diff --git a/server/node_modules/side-channel-weakmap/.eslintrc b/server/node_modules/side-channel-weakmap/.eslintrc
new file mode 100644
index 0000000..9b13ad8
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/.eslintrc
@@ -0,0 +1,12 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"id-length": 0,
+		"max-lines-per-function": 0,
+		"multiline-comment-style": 1,
+		"new-cap": [2, { "capIsNewExceptions": ["GetIntrinsic"] }],
+	},
+}
diff --git a/server/node_modules/side-channel-weakmap/.github/FUNDING.yml b/server/node_modules/side-channel-weakmap/.github/FUNDING.yml
new file mode 100644
index 0000000..2ae71cd
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/side-channel-weakmap
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/side-channel-weakmap/.nycrc b/server/node_modules/side-channel-weakmap/.nycrc
new file mode 100644
index 0000000..1826526
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/.nycrc
@@ -0,0 +1,13 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"lines": 86,
+	"statements": 85.93,
+	"functions": 82.43,
+	"branches": 76.06,
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/side-channel-weakmap/CHANGELOG.md b/server/node_modules/side-channel-weakmap/CHANGELOG.md
new file mode 100644
index 0000000..aba7ab0
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/CHANGELOG.md
@@ -0,0 +1,28 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.0.2](https://github.com/ljharb/side-channel-weakmap/compare/v1.0.1...v1.0.2) - 2024-12-10
+
+### Commits
+
+- [types] fix generics ordering [`1b62e94`](https://github.com/ljharb/side-channel-weakmap/commit/1b62e94a2ad6ed30b640ba73c4a2535836c67289)
+
+## [v1.0.1](https://github.com/ljharb/side-channel-weakmap/compare/v1.0.0...v1.0.1) - 2024-12-10
+
+### Commits
+
+- [types] fix generics ordering [`08a4a5d`](https://github.com/ljharb/side-channel-weakmap/commit/08a4a5dbffedc3ebc79f1aaaf5a3dd6d2196dc1b)
+- [Deps] update `side-channel-map` [`b53fe44`](https://github.com/ljharb/side-channel-weakmap/commit/b53fe447dfdd3a9aebedfd015b384eac17fce916)
+
+## v1.0.0 - 2024-12-10
+
+### Commits
+
+- Initial implementation, tests, readme, types [`53c0fa4`](https://github.com/ljharb/side-channel-weakmap/commit/53c0fa4788435a006f58b9d7b43cb65989ecee49)
+- Initial commit [`a157947`](https://github.com/ljharb/side-channel-weakmap/commit/a157947f26fcaf2c4a941d3a044e76bf67343532)
+- npm init [`54dfc55`](https://github.com/ljharb/side-channel-weakmap/commit/54dfc55bafb16265910d5aad4e743c43aee5bbbb)
+- Only apps should have lockfiles [`0ddd6c7`](https://github.com/ljharb/side-channel-weakmap/commit/0ddd6c7b07fe8ee04d67b2e9f7255af7ce62c07d)
diff --git a/server/node_modules/side-channel-weakmap/LICENSE b/server/node_modules/side-channel-weakmap/LICENSE
new file mode 100644
index 0000000..3900dd7
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2019 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/side-channel-weakmap/README.md b/server/node_modules/side-channel-weakmap/README.md
new file mode 100644
index 0000000..856ee36
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/README.md
@@ -0,0 +1,62 @@
+# side-channel-weakmap <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+Store information about any JS value in a side channel. Uses WeakMap if available.
+
+Warning: this implementation will leak memory until you `delete` the `key`.
+Use [`side-channel`](https://npmjs.com/side-channel) for the best available strategy.
+
+## Getting started
+
+```sh
+npm install --save side-channel-weakmap
+```
+
+## Usage/Examples
+
+```js
+const assert = require('assert');
+const getSideChannelList = require('side-channel-weakmap');
+
+const channel = getSideChannelList();
+
+const key = {};
+assert.equal(channel.has(key), false);
+assert.throws(() => channel.assert(key), TypeError);
+
+channel.set(key, 42);
+
+channel.assert(key); // does not throw
+assert.equal(channel.has(key), true);
+assert.equal(channel.get(key), 42);
+
+channel.delete(key);
+assert.equal(channel.has(key), false);
+assert.throws(() => channel.assert(key), TypeError);
+```
+
+## Tests
+
+Clone the repo, `npm install`, and run `npm test`
+
+[package-url]: https://npmjs.org/package/side-channel-weakmap
+[npm-version-svg]: https://versionbadg.es/ljharb/side-channel-weakmap.svg
+[deps-svg]: https://david-dm.org/ljharb/side-channel-weakmap.svg
+[deps-url]: https://david-dm.org/ljharb/side-channel-weakmap
+[dev-deps-svg]: https://david-dm.org/ljharb/side-channel-weakmap/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/side-channel-weakmap#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/side-channel-weakmap.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/side-channel-weakmap.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/side-channel-weakmap.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=side-channel-weakmap
+[codecov-image]: https://codecov.io/gh/ljharb/side-channel-weakmap/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/side-channel-weakmap/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/side-channel-weakmap
+[actions-url]: https://github.com/ljharb/side-channel-weakmap/actions
diff --git a/server/node_modules/side-channel-weakmap/index.d.ts b/server/node_modules/side-channel-weakmap/index.d.ts
new file mode 100644
index 0000000..ce1bc2a
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/index.d.ts
@@ -0,0 +1,15 @@
+declare namespace getSideChannelWeakMap {
+	type Channel<K, V> = {
+		assert: (key: K) => void;
+		has: (key: K) => boolean;
+		get: (key: K) => V | undefined;
+		set: (key: K, value: V) => void;
+		delete: (key: K) => boolean;
+	}
+}
+
+declare function getSideChannelWeakMap<K, V>(): getSideChannelWeakMap.Channel<K, V>;
+
+declare const x: false | typeof getSideChannelWeakMap;
+
+export = x;
diff --git a/server/node_modules/side-channel-weakmap/index.js b/server/node_modules/side-channel-weakmap/index.js
new file mode 100644
index 0000000..e5b8183
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/index.js
@@ -0,0 +1,84 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+var callBound = require('call-bound');
+var inspect = require('object-inspect');
+var getSideChannelMap = require('side-channel-map');
+
+var $TypeError = require('es-errors/type');
+var $WeakMap = GetIntrinsic('%WeakMap%', true);
+
+/** @type {<K extends object, V>(thisArg: WeakMap<K, V>, key: K) => V} */
+var $weakMapGet = callBound('WeakMap.prototype.get', true);
+/** @type {<K extends object, V>(thisArg: WeakMap<K, V>, key: K, value: V) => void} */
+var $weakMapSet = callBound('WeakMap.prototype.set', true);
+/** @type {<K extends object, V>(thisArg: WeakMap<K, V>, key: K) => boolean} */
+var $weakMapHas = callBound('WeakMap.prototype.has', true);
+/** @type {<K extends object, V>(thisArg: WeakMap<K, V>, key: K) => boolean} */
+var $weakMapDelete = callBound('WeakMap.prototype.delete', true);
+
+/** @type {import('.')} */
+module.exports = $WeakMap
+	? /** @type {Exclude<import('.'), false>} */ function getSideChannelWeakMap() {
+		/** @typedef {ReturnType<typeof getSideChannelWeakMap>} Channel */
+		/** @typedef {Parameters<Channel['get']>[0]} K */
+		/** @typedef {Parameters<Channel['set']>[1]} V */
+
+		/** @type {WeakMap<K & object, V> | undefined} */ var $wm;
+		/** @type {Channel | undefined} */ var $m;
+
+		/** @type {Channel} */
+		var channel = {
+			assert: function (key) {
+				if (!channel.has(key)) {
+					throw new $TypeError('Side channel does not contain ' + inspect(key));
+				}
+			},
+			'delete': function (key) {
+				if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
+					if ($wm) {
+						return $weakMapDelete($wm, key);
+					}
+				} else if (getSideChannelMap) {
+					if ($m) {
+						return $m['delete'](key);
+					}
+				}
+				return false;
+			},
+			get: function (key) {
+				if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
+					if ($wm) {
+						return $weakMapGet($wm, key);
+					}
+				}
+				return $m && $m.get(key);
+			},
+			has: function (key) {
+				if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
+					if ($wm) {
+						return $weakMapHas($wm, key);
+					}
+				}
+				return !!$m && $m.has(key);
+			},
+			set: function (key, value) {
+				if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
+					if (!$wm) {
+						$wm = new $WeakMap();
+					}
+					$weakMapSet($wm, key, value);
+				} else if (getSideChannelMap) {
+					if (!$m) {
+						$m = getSideChannelMap();
+					}
+					// eslint-disable-next-line no-extra-parens
+					/** @type {NonNullable<typeof $m>} */ ($m).set(key, value);
+				}
+			}
+		};
+
+		// @ts-expect-error TODO: figure out why this is erroring
+		return channel;
+	}
+	: getSideChannelMap;
diff --git a/server/node_modules/side-channel-weakmap/package.json b/server/node_modules/side-channel-weakmap/package.json
new file mode 100644
index 0000000..9ef6583
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/package.json
@@ -0,0 +1,87 @@
+{
+	"name": "side-channel-weakmap",
+	"version": "1.0.2",
+	"description": "Store information about any JS value in a side channel. Uses WeakMap if available.",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./package.json": "./package.json"
+	},
+	"types": "./index.d.ts",
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prelint": "eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git')",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc -p . && attw -P",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>=10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/side-channel-weakmap.git"
+	},
+	"keywords": [
+		"weakmap",
+		"map",
+		"side",
+		"channel",
+		"metadata"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"funding": {
+		"url": "https://github.com/sponsors/ljharb"
+	},
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/side-channel-weakmap/issues"
+	},
+	"homepage": "https://github.com/ljharb/side-channel-weakmap#readme",
+	"dependencies": {
+		"call-bound": "^1.0.2",
+		"es-errors": "^1.3.0",
+		"get-intrinsic": "^1.2.5",
+		"object-inspect": "^1.13.3",
+		"side-channel-map": "^1.0.1"
+	},
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.1",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.2",
+		"@types/call-bind": "^1.0.5",
+		"@types/get-intrinsic": "^1.2.3",
+		"@types/object-inspect": "^1.13.0",
+		"@types/tape": "^5.6.5",
+		"auto-changelog": "^2.5.0",
+		"eclint": "^2.8.1",
+		"encoding": "^0.1.13",
+		"eslint": "=8.8.0",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/side-channel-weakmap/test/index.js b/server/node_modules/side-channel-weakmap/test/index.js
new file mode 100644
index 0000000..a01248b
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/test/index.js
@@ -0,0 +1,114 @@
+'use strict';
+
+var test = require('tape');
+
+var getSideChannelWeakMap = require('../');
+
+test('getSideChannelMap', { skip: typeof WeakMap !== 'function' && typeof Map !== 'function' }, function (t) {
+	var getSideChannel = getSideChannelWeakMap || function () {
+		throw new EvalError('should never happen');
+	};
+
+	t.test('export', function (st) {
+		st.equal(typeof getSideChannel, 'function', 'is a function');
+
+		st.equal(getSideChannel.length, 0, 'takes no arguments');
+
+		var channel = getSideChannel();
+		st.ok(channel, 'is truthy');
+		st.equal(typeof channel, 'object', 'is an object');
+		st.end();
+	});
+
+	t.test('assert', function (st) {
+		var channel = getSideChannel();
+		st['throws'](
+			function () { channel.assert({}); },
+			TypeError,
+			'nonexistent value throws'
+		);
+
+		var o = {};
+		channel.set(o, 'data');
+		st.doesNotThrow(function () { channel.assert(o); }, 'existent value noops');
+
+		st.end();
+	});
+
+	t.test('has', function (st) {
+		var channel = getSideChannel();
+		/** @type {unknown[]} */ var o = [];
+
+		st.equal(channel.has(o), false, 'nonexistent value yields false');
+
+		channel.set(o, 'foo');
+		st.equal(channel.has(o), true, 'existent value yields true');
+
+		st.equal(channel.has('abc'), false, 'non object value non existent yields false');
+
+		channel.set('abc', 'foo');
+		st.equal(channel.has('abc'), true, 'non object value that exists yields true');
+
+		st.end();
+	});
+
+	t.test('get', function (st) {
+		var channel = getSideChannel();
+		var o = {};
+		st.equal(channel.get(o), undefined, 'nonexistent value yields undefined');
+
+		var data = {};
+		channel.set(o, data);
+		st.equal(channel.get(o), data, '"get" yields data set by "set"');
+
+		st.end();
+	});
+
+	t.test('set', function (st) {
+		var channel = getSideChannel();
+		var o = function () {};
+		st.equal(channel.get(o), undefined, 'value not set');
+
+		channel.set(o, 42);
+		st.equal(channel.get(o), 42, 'value was set');
+
+		channel.set(o, Infinity);
+		st.equal(channel.get(o), Infinity, 'value was set again');
+
+		var o2 = {};
+		channel.set(o2, 17);
+		st.equal(channel.get(o), Infinity, 'o is not modified');
+		st.equal(channel.get(o2), 17, 'o2 is set');
+
+		channel.set(o, 14);
+		st.equal(channel.get(o), 14, 'o is modified');
+		st.equal(channel.get(o2), 17, 'o2 is not modified');
+
+		st.end();
+	});
+
+	t.test('delete', function (st) {
+		var channel = getSideChannel();
+		var o = {};
+		st.equal(channel['delete']({}), false, 'nonexistent value yields false');
+
+		channel.set(o, 42);
+		st.equal(channel.has(o), true, 'value is set');
+
+		st.equal(channel['delete']({}), false, 'nonexistent value still yields false');
+
+		st.equal(channel['delete'](o), true, 'deleted value yields true');
+
+		st.equal(channel.has(o), false, 'value is no longer set');
+
+		st.end();
+	});
+
+	t.end();
+});
+
+test('getSideChannelMap, no WeakMaps and/or Maps', { skip: typeof WeakMap === 'function' || typeof Map === 'function' }, function (t) {
+	t.equal(getSideChannelWeakMap, false, 'is false');
+
+	t.end();
+});
diff --git a/server/node_modules/side-channel-weakmap/tsconfig.json b/server/node_modules/side-channel-weakmap/tsconfig.json
new file mode 100644
index 0000000..d9a6668
--- /dev/null
+++ b/server/node_modules/side-channel-weakmap/tsconfig.json
@@ -0,0 +1,9 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "es2021",
+	},
+	"exclude": [
+		"coverage",
+	],
+}
diff --git a/server/node_modules/side-channel/.editorconfig b/server/node_modules/side-channel/.editorconfig
new file mode 100644
index 0000000..72e0eba
--- /dev/null
+++ b/server/node_modules/side-channel/.editorconfig
@@ -0,0 +1,9 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = tab
+indent_size = 2
+trim_trailing_whitespace = true
diff --git a/server/node_modules/side-channel/.eslintrc b/server/node_modules/side-channel/.eslintrc
new file mode 100644
index 0000000..9b13ad8
--- /dev/null
+++ b/server/node_modules/side-channel/.eslintrc
@@ -0,0 +1,12 @@
+{
+	"root": true,
+
+	"extends": "@ljharb",
+
+	"rules": {
+		"id-length": 0,
+		"max-lines-per-function": 0,
+		"multiline-comment-style": 1,
+		"new-cap": [2, { "capIsNewExceptions": ["GetIntrinsic"] }],
+	},
+}
diff --git a/server/node_modules/side-channel/.github/FUNDING.yml b/server/node_modules/side-channel/.github/FUNDING.yml
new file mode 100644
index 0000000..2a94840
--- /dev/null
+++ b/server/node_modules/side-channel/.github/FUNDING.yml
@@ -0,0 +1,12 @@
+# These are supported funding model platforms
+
+github: [ljharb]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: # Replace with a single Ko-fi username
+tidelift: npm/side-channel
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']
diff --git a/server/node_modules/side-channel/.nycrc b/server/node_modules/side-channel/.nycrc
new file mode 100644
index 0000000..1826526
--- /dev/null
+++ b/server/node_modules/side-channel/.nycrc
@@ -0,0 +1,13 @@
+{
+	"all": true,
+	"check-coverage": false,
+	"reporter": ["text-summary", "text", "html", "json"],
+	"lines": 86,
+	"statements": 85.93,
+	"functions": 82.43,
+	"branches": 76.06,
+	"exclude": [
+		"coverage",
+		"test"
+	]
+}
diff --git a/server/node_modules/side-channel/CHANGELOG.md b/server/node_modules/side-channel/CHANGELOG.md
new file mode 100644
index 0000000..58e378c
--- /dev/null
+++ b/server/node_modules/side-channel/CHANGELOG.md
@@ -0,0 +1,110 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.1.0](https://github.com/ljharb/side-channel/compare/v1.0.6...v1.1.0) - 2024-12-11
+
+### Commits
+
+- [Refactor] extract implementations to `side-channel-weakmap`, `side-channel-map`, `side-channel-list` [`ada5955`](https://github.com/ljharb/side-channel/commit/ada595549a5c4c6c853756d598846b180941c6da)
+- [New] add `channel.delete` [`c01d2d3`](https://github.com/ljharb/side-channel/commit/c01d2d3fd51dbb1ce6da72ad7916e61bd6172aad)
+- [types] improve types [`0c54356`](https://github.com/ljharb/side-channel/commit/0c5435651417df41b8cc1a5f7cdce8bffae68cde)
+- [readme] add content [`be24868`](https://github.com/ljharb/side-channel/commit/be248682ac294b0e22c883092c45985aa91c490a)
+- [actions] split out node 10-20, and 20+ [`c4488e2`](https://github.com/ljharb/side-channel/commit/c4488e241ef3d49a19fe266ac830a2e644305911)
+- [types] use shared tsconfig [`0e0d57c`](https://github.com/ljharb/side-channel/commit/0e0d57c2ff17c7b45c6cbd43ebcf553edc9e3adc)
+- [Dev Deps] update `@ljharb/eslint-config`, `@ljharb/tsconfig`, `@types/get-intrinsic`, `@types/object-inspect`, `@types/tape`, `auto-changelog`, `tape` [`fb4f622`](https://github.com/ljharb/side-channel/commit/fb4f622e64a99a1e40b6e5cd7691674a9dc429e4)
+- [Deps] update `call-bind`, `get-intrinsic`, `object-inspect` [`b78336b`](https://github.com/ljharb/side-channel/commit/b78336b886172d1b457d414ac9e28de8c5fecc78)
+- [Tests] replace `aud` with `npm audit` [`ee3ab46`](https://github.com/ljharb/side-channel/commit/ee3ab4690d954311c35115651bcfd45edd205aa1)
+- [Dev Deps] add missing peer dep [`c03e21a`](https://github.com/ljharb/side-channel/commit/c03e21a7def3b67cdc15ae22316884fefcb2f6a8)
+
+## [v1.0.6](https://github.com/ljharb/side-channel/compare/v1.0.5...v1.0.6) - 2024-02-29
+
+### Commits
+
+- add types [`9beef66`](https://github.com/ljharb/side-channel/commit/9beef6643e6d717ea57bedabf86448123a7dd9e9)
+- [meta] simplify `exports` [`4334cf9`](https://github.com/ljharb/side-channel/commit/4334cf9df654151504c383b62a2f9ebdc8d9d5ac)
+- [Deps] update `call-bind` [`d6043c4`](https://github.com/ljharb/side-channel/commit/d6043c4d8f4d7be9037dd0f0419c7a2e0e39ec6a)
+- [Dev Deps] update `tape` [`6aca376`](https://github.com/ljharb/side-channel/commit/6aca3761868dc8cd5ff7fd9799bf6b95e09a6eb0)
+
+## [v1.0.5](https://github.com/ljharb/side-channel/compare/v1.0.4...v1.0.5) - 2024-02-06
+
+### Commits
+
+- [actions] reuse common workflows [`3d2e1ff`](https://github.com/ljharb/side-channel/commit/3d2e1ffd16dd6eaaf3e40ff57951f840d2d63c04)
+- [meta] use `npmignore` to autogenerate an npmignore file [`04296ea`](https://github.com/ljharb/side-channel/commit/04296ea17d1544b0a5d20fd5bfb31aa4f6513eb9)
+- [meta] add `.editorconfig`; add `eclint` [`130f0a6`](https://github.com/ljharb/side-channel/commit/130f0a6adbc04d385c7456a601d38344dce3d6a9)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `auto-changelog`, `safe-publish-latest`, `tape` [`d480c2f`](https://github.com/ljharb/side-channel/commit/d480c2fbe757489ae9b4275491ffbcc3ac4725e9)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `auto-changelog`, `tape` [`ecbe70e`](https://github.com/ljharb/side-channel/commit/ecbe70e53a418234081a77971fec1fdfae20c841)
+- [actions] update rebase action [`75240b9`](https://github.com/ljharb/side-channel/commit/75240b9963b816e8846400d2287cb68f88c7fba7)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud`, `npmignore`, `tape` [`ae8d281`](https://github.com/ljharb/side-channel/commit/ae8d281572430099109870fd9430d2ca3f320b8d)
+- [Dev Deps] update `@ljharb/eslint-config`, `aud`, `tape` [`7125b88`](https://github.com/ljharb/side-channel/commit/7125b885fd0eacad4fee9b073b72d14065ece278)
+- [Deps] update `call-bind`, `get-intrinsic`, `object-inspect` [`82577c9`](https://github.com/ljharb/side-channel/commit/82577c9796304519139a570f82a317211b5f3b86)
+- [Deps] update `call-bind`, `get-intrinsic`, `object-inspect` [`550aadf`](https://github.com/ljharb/side-channel/commit/550aadf20475a6081fd70304cc54f77259a5c8a8)
+- [Tests] increase coverage [`5130877`](https://github.com/ljharb/side-channel/commit/5130877a7b27c862e64e6d1c12a178b28808859d)
+- [Deps] update `get-intrinsic`, `object-inspect` [`ba0194c`](https://github.com/ljharb/side-channel/commit/ba0194c505b1a8a0427be14cadd5b8a46d4d01b8)
+- [meta] add missing `engines.node` [`985fd24`](https://github.com/ljharb/side-channel/commit/985fd249663cb06617a693a94fe08cad12f5cb70)
+- [Refactor] use `es-errors`, so things that only need those do not need `get-intrinsic` [`40227a8`](https://github.com/ljharb/side-channel/commit/40227a87b01709ad2c0eebf87eb4223a800099b9)
+- [Deps] update `get-intrinsic` [`a989b40`](https://github.com/ljharb/side-channel/commit/a989b4024958737ae7be9fbffdeff2078f33a0fd)
+- [Deps] update `object-inspect` [`aec42d2`](https://github.com/ljharb/side-channel/commit/aec42d2ec541a31aaa02475692c87d489237d9a3)
+
+## [v1.0.4](https://github.com/ljharb/side-channel/compare/v1.0.3...v1.0.4) - 2020-12-29
+
+### Commits
+
+- [Tests] migrate tests to Github Actions [`10909cb`](https://github.com/ljharb/side-channel/commit/10909cbf8ce9c0bf96f604cf13d7ffd5a22c2d40)
+- [Refactor] Use a linked list rather than an array, and move accessed nodes to the beginning [`195613f`](https://github.com/ljharb/side-channel/commit/195613f28b5c1e6072ef0b61b5beebaf2b6a304e)
+- [meta] do not publish github action workflow files [`290ec29`](https://github.com/ljharb/side-channel/commit/290ec29cd21a60585145b4a7237ec55228c52c27)
+- [Tests] run `nyc` on all tests; use `tape` runner [`ea6d030`](https://github.com/ljharb/side-channel/commit/ea6d030ff3fe6be2eca39e859d644c51ecd88869)
+- [actions] add "Allow Edits" workflow [`d464d8f`](https://github.com/ljharb/side-channel/commit/d464d8fe52b5eddf1504a0ed97f0941a90f32c15)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `auto-changelog` [`02daca8`](https://github.com/ljharb/side-channel/commit/02daca87c6809821c97be468d1afa2f5ef447383)
+- [Refactor] use `call-bind` and `get-intrinsic` instead of `es-abstract` [`e09d481`](https://github.com/ljharb/side-channel/commit/e09d481528452ebafa5cdeae1af665c35aa2deee)
+- [Deps] update `object.assign` [`ee83aa8`](https://github.com/ljharb/side-channel/commit/ee83aa81df313b5e46319a63adb05cf0c179079a)
+- [actions] update rebase action to use checkout v2 [`7726b0b`](https://github.com/ljharb/side-channel/commit/7726b0b058b632fccea709f58960871defaaa9d7)
+
+## [v1.0.3](https://github.com/ljharb/side-channel/compare/v1.0.2...v1.0.3) - 2020-08-23
+
+### Commits
+
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `aud`, `auto-changelog`, `tape` [`1f10561`](https://github.com/ljharb/side-channel/commit/1f105611ef3acf32dec8032ae5c0baa5e56bb868)
+- [Deps] update `es-abstract`, `object-inspect` [`bc20159`](https://github.com/ljharb/side-channel/commit/bc201597949a505e37cef9eaf24c7010831e6f03)
+- [Dev Deps] update `@ljharb/eslint-config`, `tape` [`b9b2b22`](https://github.com/ljharb/side-channel/commit/b9b2b225f9e0ea72a6ec2b89348f0bd690bc9ed1)
+- [Dev Deps] update `eslint`, `@ljharb/eslint-config`, `tape` [`7055ab4`](https://github.com/ljharb/side-channel/commit/7055ab4de0860606efd2003674a74f1fe6ebc07e)
+- [Dev Deps] update `auto-changelog`; add `aud` [`d278c37`](https://github.com/ljharb/side-channel/commit/d278c37d08227be4f84aa769fcd919e73feeba40)
+- [actions] switch Automatic Rebase workflow to `pull_request_target` event [`3bcf982`](https://github.com/ljharb/side-channel/commit/3bcf982faa122745b39c33ce83d32fdf003741c6)
+- [Tests] only audit prod deps [`18d01c4`](https://github.com/ljharb/side-channel/commit/18d01c4015b82a3d75044c4d5ba7917b2eac01ec)
+- [Deps] update `es-abstract` [`6ab096d`](https://github.com/ljharb/side-channel/commit/6ab096d9de2b482cf5e0717e34e212f5b2b9bc9a)
+- [Dev Deps] update `tape` [`9dc174c`](https://github.com/ljharb/side-channel/commit/9dc174cc651dfd300b4b72da936a0a7eda5f9452)
+- [Deps] update `es-abstract` [`431d0f0`](https://github.com/ljharb/side-channel/commit/431d0f0ff11fbd2ae6f3115582a356d3a1cfce82)
+- [Deps] update `es-abstract` [`49869fd`](https://github.com/ljharb/side-channel/commit/49869fd323bf4453f0ba515c0fb265cf5ab7b932)
+- [meta] Add package.json to package's exports [`77d9cdc`](https://github.com/ljharb/side-channel/commit/77d9cdceb2a9e47700074f2ae0c0a202e7dac0d4)
+
+## [v1.0.2](https://github.com/ljharb/side-channel/compare/v1.0.1...v1.0.2) - 2019-12-20
+
+### Commits
+
+- [Dev Deps] update `@ljharb/eslint-config`, `tape` [`4a526df`](https://github.com/ljharb/side-channel/commit/4a526df44e4701566ed001ec78546193f818b082)
+- [Deps] update `es-abstract` [`d4f6e62`](https://github.com/ljharb/side-channel/commit/d4f6e629b6fb93a07415db7f30d3c90fd7f264fe)
+
+## [v1.0.1](https://github.com/ljharb/side-channel/compare/v1.0.0...v1.0.1) - 2019-12-01
+
+### Commits
+
+- [Fix] add missing "exports" [`d212907`](https://github.com/ljharb/side-channel/commit/d2129073abf0701a5343bf28aa2145617604dc2e)
+
+## v1.0.0 - 2019-12-01
+
+### Commits
+
+- Initial implementation [`dbebd3a`](https://github.com/ljharb/side-channel/commit/dbebd3a4b5ed64242f9a6810efe7c4214cd8cde4)
+- Initial tests [`73bdefe`](https://github.com/ljharb/side-channel/commit/73bdefe568c9076cf8c0b8719bc2141aec0e19b8)
+- Initial commit [`43c03e1`](https://github.com/ljharb/side-channel/commit/43c03e1c2849ec50a87b7a5cd76238a62b0b8770)
+- npm init [`5c090a7`](https://github.com/ljharb/side-channel/commit/5c090a765d66a5527d9889b89aeff78dee91348c)
+- [meta] add `auto-changelog` [`a5c4e56`](https://github.com/ljharb/side-channel/commit/a5c4e5675ec02d5eb4d84b4243aeea2a1d38fbec)
+- [actions] add automatic rebasing / merge commit blocking [`bab1683`](https://github.com/ljharb/side-channel/commit/bab1683d8f9754b086e94397699fdc645e0d7077)
+- [meta] add `funding` field; create FUNDING.yml [`63d7aea`](https://github.com/ljharb/side-channel/commit/63d7aeaf34f5650650ae97ca4b9fae685bd0937c)
+- [Tests] add `npm run lint` [`46a5a81`](https://github.com/ljharb/side-channel/commit/46a5a81705cd2664f83df232c01dbbf2ee952885)
+- Only apps should have lockfiles [`8b16b03`](https://github.com/ljharb/side-channel/commit/8b16b0305f00895d90c4e2e5773c854cfea0e448)
+- [meta] add `safe-publish-latest` [`2f098ef`](https://github.com/ljharb/side-channel/commit/2f098ef092a39399cfe548b19a1fc03c2fd2f490)
diff --git a/server/node_modules/side-channel/LICENSE b/server/node_modules/side-channel/LICENSE
new file mode 100644
index 0000000..3900dd7
--- /dev/null
+++ b/server/node_modules/side-channel/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2019 Jordan Harband
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/side-channel/README.md b/server/node_modules/side-channel/README.md
new file mode 100644
index 0000000..cc7e103
--- /dev/null
+++ b/server/node_modules/side-channel/README.md
@@ -0,0 +1,61 @@
+# side-channel <sup>[![Version Badge][npm-version-svg]][package-url]</sup>
+
+[![github actions][actions-image]][actions-url]
+[![coverage][codecov-image]][codecov-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+[![npm badge][npm-badge-png]][package-url]
+
+Store information about any JS value in a side channel. Uses WeakMap if available.
+
+Warning: in an environment that lacks `WeakMap`, this implementation will leak memory until you `delete` the `key`.
+
+## Getting started
+
+```sh
+npm install --save side-channel
+```
+
+## Usage/Examples
+
+```js
+const assert = require('assert');
+const getSideChannel = require('side-channel');
+
+const channel = getSideChannel();
+
+const key = {};
+assert.equal(channel.has(key), false);
+assert.throws(() => channel.assert(key), TypeError);
+
+channel.set(key, 42);
+
+channel.assert(key); // does not throw
+assert.equal(channel.has(key), true);
+assert.equal(channel.get(key), 42);
+
+channel.delete(key);
+assert.equal(channel.has(key), false);
+assert.throws(() => channel.assert(key), TypeError);
+```
+
+## Tests
+
+Clone the repo, `npm install`, and run `npm test`
+
+[package-url]: https://npmjs.org/package/side-channel
+[npm-version-svg]: https://versionbadg.es/ljharb/side-channel.svg
+[deps-svg]: https://david-dm.org/ljharb/side-channel.svg
+[deps-url]: https://david-dm.org/ljharb/side-channel
+[dev-deps-svg]: https://david-dm.org/ljharb/side-channel/dev-status.svg
+[dev-deps-url]: https://david-dm.org/ljharb/side-channel#info=devDependencies
+[npm-badge-png]: https://nodei.co/npm/side-channel.png?downloads=true&stars=true
+[license-image]: https://img.shields.io/npm/l/side-channel.svg
+[license-url]: LICENSE
+[downloads-image]: https://img.shields.io/npm/dm/side-channel.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=side-channel
+[codecov-image]: https://codecov.io/gh/ljharb/side-channel/branch/main/graphs/badge.svg
+[codecov-url]: https://app.codecov.io/gh/ljharb/side-channel/
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/ljharb/side-channel
+[actions-url]: https://github.com/ljharb/side-channel/actions
diff --git a/server/node_modules/side-channel/index.d.ts b/server/node_modules/side-channel/index.d.ts
new file mode 100644
index 0000000..18c6317
--- /dev/null
+++ b/server/node_modules/side-channel/index.d.ts
@@ -0,0 +1,14 @@
+import getSideChannelList from 'side-channel-list';
+import getSideChannelMap from 'side-channel-map';
+import getSideChannelWeakMap from 'side-channel-weakmap';
+
+declare namespace getSideChannel {
+	type Channel<K, V> =
+		| getSideChannelList.Channel<K, V>
+		| ReturnType<Exclude<typeof getSideChannelMap<K, V>, false>>
+		| ReturnType<Exclude<typeof getSideChannelWeakMap<K, V>, false>>;
+}
+
+declare function getSideChannel<K, V>(): getSideChannel.Channel<K, V>;
+
+export = getSideChannel;
diff --git a/server/node_modules/side-channel/index.js b/server/node_modules/side-channel/index.js
new file mode 100644
index 0000000..a8a9b05
--- /dev/null
+++ b/server/node_modules/side-channel/index.js
@@ -0,0 +1,43 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+var inspect = require('object-inspect');
+var getSideChannelList = require('side-channel-list');
+var getSideChannelMap = require('side-channel-map');
+var getSideChannelWeakMap = require('side-channel-weakmap');
+
+var makeChannel = getSideChannelWeakMap || getSideChannelMap || getSideChannelList;
+
+/** @type {import('.')} */
+module.exports = function getSideChannel() {
+	/** @typedef {ReturnType<typeof getSideChannel>} Channel */
+
+	/** @type {Channel | undefined} */ var $channelData;
+
+	/** @type {Channel} */
+	var channel = {
+		assert: function (key) {
+			if (!channel.has(key)) {
+				throw new $TypeError('Side channel does not contain ' + inspect(key));
+			}
+		},
+		'delete': function (key) {
+			return !!$channelData && $channelData['delete'](key);
+		},
+		get: function (key) {
+			return $channelData && $channelData.get(key);
+		},
+		has: function (key) {
+			return !!$channelData && $channelData.has(key);
+		},
+		set: function (key, value) {
+			if (!$channelData) {
+				$channelData = makeChannel();
+			}
+
+			$channelData.set(key, value);
+		}
+	};
+	// @ts-expect-error TODO: figure out why this is erroring
+	return channel;
+};
diff --git a/server/node_modules/side-channel/package.json b/server/node_modules/side-channel/package.json
new file mode 100644
index 0000000..30fa42c
--- /dev/null
+++ b/server/node_modules/side-channel/package.json
@@ -0,0 +1,85 @@
+{
+	"name": "side-channel",
+	"version": "1.1.0",
+	"description": "Store information about any JS value in a side channel. Uses WeakMap if available.",
+	"main": "index.js",
+	"exports": {
+		".": "./index.js",
+		"./package.json": "./package.json"
+	},
+	"types": "./index.d.ts",
+	"scripts": {
+		"prepack": "npmignore --auto --commentLines=autogenerated",
+		"prepublishOnly": "safe-publish-latest",
+		"prepublish": "not-in-publish || npm run prepublishOnly",
+		"prelint": "eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git')",
+		"lint": "eslint --ext=js,mjs .",
+		"postlint": "tsc -p . && attw -P",
+		"pretest": "npm run lint",
+		"tests-only": "nyc tape 'test/**/*.js'",
+		"test": "npm run tests-only",
+		"posttest": "npx npm@'>=10.2' audit --production",
+		"version": "auto-changelog && git add CHANGELOG.md",
+		"postversion": "auto-changelog && git add CHANGELOG.md && git commit --no-edit --amend && git tag -f \"v$(node -e \"console.log(require('./package.json').version)\")\""
+	},
+	"repository": {
+		"type": "git",
+		"url": "git+https://github.com/ljharb/side-channel.git"
+	},
+	"keywords": [
+		"weakmap",
+		"map",
+		"side",
+		"channel",
+		"metadata"
+	],
+	"author": "Jordan Harband <ljharb@gmail.com>",
+	"funding": {
+		"url": "https://github.com/sponsors/ljharb"
+	},
+	"license": "MIT",
+	"bugs": {
+		"url": "https://github.com/ljharb/side-channel/issues"
+	},
+	"homepage": "https://github.com/ljharb/side-channel#readme",
+	"dependencies": {
+		"es-errors": "^1.3.0",
+		"object-inspect": "^1.13.3",
+		"side-channel-list": "^1.0.0",
+		"side-channel-map": "^1.0.1",
+		"side-channel-weakmap": "^1.0.2"
+	},
+	"devDependencies": {
+		"@arethetypeswrong/cli": "^0.17.1",
+		"@ljharb/eslint-config": "^21.1.1",
+		"@ljharb/tsconfig": "^0.2.2",
+		"@types/object-inspect": "^1.13.0",
+		"@types/tape": "^5.6.5",
+		"auto-changelog": "^2.5.0",
+		"eclint": "^2.8.1",
+		"encoding": "^0.1.13",
+		"eslint": "=8.8.0",
+		"in-publish": "^2.0.1",
+		"npmignore": "^0.3.1",
+		"nyc": "^10.3.2",
+		"safe-publish-latest": "^2.0.0",
+		"tape": "^5.9.0",
+		"typescript": "next"
+	},
+	"auto-changelog": {
+		"output": "CHANGELOG.md",
+		"template": "keepachangelog",
+		"unreleased": false,
+		"commitLimit": false,
+		"backfillLimit": false,
+		"hideCredit": true
+	},
+	"publishConfig": {
+		"ignore": [
+			".github/workflows"
+		]
+	},
+	"engines": {
+		"node": ">= 0.4"
+	}
+}
diff --git a/server/node_modules/side-channel/test/index.js b/server/node_modules/side-channel/test/index.js
new file mode 100644
index 0000000..bd1e7c2
--- /dev/null
+++ b/server/node_modules/side-channel/test/index.js
@@ -0,0 +1,104 @@
+'use strict';
+
+var test = require('tape');
+
+var getSideChannel = require('../');
+
+test('getSideChannel', function (t) {
+	t.test('export', function (st) {
+		st.equal(typeof getSideChannel, 'function', 'is a function');
+
+		st.equal(getSideChannel.length, 0, 'takes no arguments');
+
+		var channel = getSideChannel();
+		st.ok(channel, 'is truthy');
+		st.equal(typeof channel, 'object', 'is an object');
+		st.end();
+	});
+
+	t.test('assert', function (st) {
+		var channel = getSideChannel();
+		st['throws'](
+			function () { channel.assert({}); },
+			TypeError,
+			'nonexistent value throws'
+		);
+
+		var o = {};
+		channel.set(o, 'data');
+		st.doesNotThrow(function () { channel.assert(o); }, 'existent value noops');
+
+		st.end();
+	});
+
+	t.test('has', function (st) {
+		var channel = getSideChannel();
+		/** @type {unknown[]} */ var o = [];
+
+		st.equal(channel.has(o), false, 'nonexistent value yields false');
+
+		channel.set(o, 'foo');
+		st.equal(channel.has(o), true, 'existent value yields true');
+
+		st.equal(channel.has('abc'), false, 'non object value non existent yields false');
+
+		channel.set('abc', 'foo');
+		st.equal(channel.has('abc'), true, 'non object value that exists yields true');
+
+		st.end();
+	});
+
+	t.test('get', function (st) {
+		var channel = getSideChannel();
+		var o = {};
+		st.equal(channel.get(o), undefined, 'nonexistent value yields undefined');
+
+		var data = {};
+		channel.set(o, data);
+		st.equal(channel.get(o), data, '"get" yields data set by "set"');
+
+		st.end();
+	});
+
+	t.test('set', function (st) {
+		var channel = getSideChannel();
+		var o = function () {};
+		st.equal(channel.get(o), undefined, 'value not set');
+
+		channel.set(o, 42);
+		st.equal(channel.get(o), 42, 'value was set');
+
+		channel.set(o, Infinity);
+		st.equal(channel.get(o), Infinity, 'value was set again');
+
+		var o2 = {};
+		channel.set(o2, 17);
+		st.equal(channel.get(o), Infinity, 'o is not modified');
+		st.equal(channel.get(o2), 17, 'o2 is set');
+
+		channel.set(o, 14);
+		st.equal(channel.get(o), 14, 'o is modified');
+		st.equal(channel.get(o2), 17, 'o2 is not modified');
+
+		st.end();
+	});
+
+	t.test('delete', function (st) {
+		var channel = getSideChannel();
+		var o = {};
+		st.equal(channel['delete']({}), false, 'nonexistent value yields false');
+
+		channel.set(o, 42);
+		st.equal(channel.has(o), true, 'value is set');
+
+		st.equal(channel['delete']({}), false, 'nonexistent value still yields false');
+
+		st.equal(channel['delete'](o), true, 'deleted value yields true');
+
+		st.equal(channel.has(o), false, 'value is no longer set');
+
+		st.end();
+	});
+
+	t.end();
+});
diff --git a/server/node_modules/side-channel/tsconfig.json b/server/node_modules/side-channel/tsconfig.json
new file mode 100644
index 0000000..d9a6668
--- /dev/null
+++ b/server/node_modules/side-channel/tsconfig.json
@@ -0,0 +1,9 @@
+{
+	"extends": "@ljharb/tsconfig",
+	"compilerOptions": {
+		"target": "es2021",
+	},
+	"exclude": [
+		"coverage",
+	],
+}
diff --git a/server/node_modules/signal-exit/LICENSE.txt b/server/node_modules/signal-exit/LICENSE.txt
new file mode 100644
index 0000000..eead04a
--- /dev/null
+++ b/server/node_modules/signal-exit/LICENSE.txt
@@ -0,0 +1,16 @@
+The ISC License
+
+Copyright (c) 2015, Contributors
+
+Permission to use, copy, modify, and/or distribute this software
+for any purpose with or without fee is hereby granted, provided
+that the above copyright notice and this permission notice
+appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE
+LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
+OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/signal-exit/README.md b/server/node_modules/signal-exit/README.md
new file mode 100644
index 0000000..f9c7c00
--- /dev/null
+++ b/server/node_modules/signal-exit/README.md
@@ -0,0 +1,39 @@
+# signal-exit
+
+[![Build Status](https://travis-ci.org/tapjs/signal-exit.png)](https://travis-ci.org/tapjs/signal-exit)
+[![Coverage](https://coveralls.io/repos/tapjs/signal-exit/badge.svg?branch=master)](https://coveralls.io/r/tapjs/signal-exit?branch=master)
+[![NPM version](https://img.shields.io/npm/v/signal-exit.svg)](https://www.npmjs.com/package/signal-exit)
+[![Standard Version](https://img.shields.io/badge/release-standard%20version-brightgreen.svg)](https://github.com/conventional-changelog/standard-version)
+
+When you want to fire an event no matter how a process exits:
+
+* reaching the end of execution.
+* explicitly having `process.exit(code)` called.
+* having `process.kill(pid, sig)` called.
+* receiving a fatal signal from outside the process
+
+Use `signal-exit`.
+
+```js
+var onExit = require('signal-exit')
+
+onExit(function (code, signal) {
+  console.log('process exited!')
+})
+```
+
+## API
+
+`var remove = onExit(function (code, signal) {}, options)`
+
+The return value of the function is a function that will remove the
+handler.
+
+Note that the function *only* fires for signals if the signal would
+cause the process to exit.  That is, there are no other listeners, and
+it is a fatal signal.
+
+## Options
+
+* `alwaysLast`: Run this handler after any other signal or exit
+  handlers.  This causes `process.emit` to be monkeypatched.
diff --git a/server/node_modules/signal-exit/index.js b/server/node_modules/signal-exit/index.js
new file mode 100644
index 0000000..93703f3
--- /dev/null
+++ b/server/node_modules/signal-exit/index.js
@@ -0,0 +1,202 @@
+// Note: since nyc uses this module to output coverage, any lines
+// that are in the direct sync flow of nyc's outputCoverage are
+// ignored, since we can never get coverage for them.
+// grab a reference to node's real process object right away
+var process = global.process
+
+const processOk = function (process) {
+  return process &&
+    typeof process === 'object' &&
+    typeof process.removeListener === 'function' &&
+    typeof process.emit === 'function' &&
+    typeof process.reallyExit === 'function' &&
+    typeof process.listeners === 'function' &&
+    typeof process.kill === 'function' &&
+    typeof process.pid === 'number' &&
+    typeof process.on === 'function'
+}
+
+// some kind of non-node environment, just no-op
+/* istanbul ignore if */
+if (!processOk(process)) {
+  module.exports = function () {
+    return function () {}
+  }
+} else {
+  var assert = require('assert')
+  var signals = require('./signals.js')
+  var isWin = /^win/i.test(process.platform)
+
+  var EE = require('events')
+  /* istanbul ignore if */
+  if (typeof EE !== 'function') {
+    EE = EE.EventEmitter
+  }
+
+  var emitter
+  if (process.__signal_exit_emitter__) {
+    emitter = process.__signal_exit_emitter__
+  } else {
+    emitter = process.__signal_exit_emitter__ = new EE()
+    emitter.count = 0
+    emitter.emitted = {}
+  }
+
+  // Because this emitter is a global, we have to check to see if a
+  // previous version of this library failed to enable infinite listeners.
+  // I know what you're about to say.  But literally everything about
+  // signal-exit is a compromise with evil.  Get used to it.
+  if (!emitter.infinite) {
+    emitter.setMaxListeners(Infinity)
+    emitter.infinite = true
+  }
+
+  module.exports = function (cb, opts) {
+    /* istanbul ignore if */
+    if (!processOk(global.process)) {
+      return function () {}
+    }
+    assert.equal(typeof cb, 'function', 'a callback must be provided for exit handler')
+
+    if (loaded === false) {
+      load()
+    }
+
+    var ev = 'exit'
+    if (opts && opts.alwaysLast) {
+      ev = 'afterexit'
+    }
+
+    var remove = function () {
+      emitter.removeListener(ev, cb)
+      if (emitter.listeners('exit').length === 0 &&
+          emitter.listeners('afterexit').length === 0) {
+        unload()
+      }
+    }
+    emitter.on(ev, cb)
+
+    return remove
+  }
+
+  var unload = function unload () {
+    if (!loaded || !processOk(global.process)) {
+      return
+    }
+    loaded = false
+
+    signals.forEach(function (sig) {
+      try {
+        process.removeListener(sig, sigListeners[sig])
+      } catch (er) {}
+    })
+    process.emit = originalProcessEmit
+    process.reallyExit = originalProcessReallyExit
+    emitter.count -= 1
+  }
+  module.exports.unload = unload
+
+  var emit = function emit (event, code, signal) {
+    /* istanbul ignore if */
+    if (emitter.emitted[event]) {
+      return
+    }
+    emitter.emitted[event] = true
+    emitter.emit(event, code, signal)
+  }
+
+  // { <signal>: <listener fn>, ... }
+  var sigListeners = {}
+  signals.forEach(function (sig) {
+    sigListeners[sig] = function listener () {
+      /* istanbul ignore if */
+      if (!processOk(global.process)) {
+        return
+      }
+      // If there are no other listeners, an exit is coming!
+      // Simplest way: remove us and then re-send the signal.
+      // We know that this will kill the process, so we can
+      // safely emit now.
+      var listeners = process.listeners(sig)
+      if (listeners.length === emitter.count) {
+        unload()
+        emit('exit', null, sig)
+        /* istanbul ignore next */
+        emit('afterexit', null, sig)
+        /* istanbul ignore next */
+        if (isWin && sig === 'SIGHUP') {
+          // "SIGHUP" throws an `ENOSYS` error on Windows,
+          // so use a supported signal instead
+          sig = 'SIGINT'
+        }
+        /* istanbul ignore next */
+        process.kill(process.pid, sig)
+      }
+    }
+  })
+
+  module.exports.signals = function () {
+    return signals
+  }
+
+  var loaded = false
+
+  var load = function load () {
+    if (loaded || !processOk(global.process)) {
+      return
+    }
+    loaded = true
+
+    // This is the number of onSignalExit's that are in play.
+    // It's important so that we can count the correct number of
+    // listeners on signals, and don't wait for the other one to
+    // handle it instead of us.
+    emitter.count += 1
+
+    signals = signals.filter(function (sig) {
+      try {
+        process.on(sig, sigListeners[sig])
+        return true
+      } catch (er) {
+        return false
+      }
+    })
+
+    process.emit = processEmit
+    process.reallyExit = processReallyExit
+  }
+  module.exports.load = load
+
+  var originalProcessReallyExit = process.reallyExit
+  var processReallyExit = function processReallyExit (code) {
+    /* istanbul ignore if */
+    if (!processOk(global.process)) {
+      return
+    }
+    process.exitCode = code || /* istanbul ignore next */ 0
+    emit('exit', process.exitCode, null)
+    /* istanbul ignore next */
+    emit('afterexit', process.exitCode, null)
+    /* istanbul ignore next */
+    originalProcessReallyExit.call(process, process.exitCode)
+  }
+
+  var originalProcessEmit = process.emit
+  var processEmit = function processEmit (ev, arg) {
+    if (ev === 'exit' && processOk(global.process)) {
+      /* istanbul ignore else */
+      if (arg !== undefined) {
+        process.exitCode = arg
+      }
+      var ret = originalProcessEmit.apply(this, arguments)
+      /* istanbul ignore next */
+      emit('exit', process.exitCode, null)
+      /* istanbul ignore next */
+      emit('afterexit', process.exitCode, null)
+      /* istanbul ignore next */
+      return ret
+    } else {
+      return originalProcessEmit.apply(this, arguments)
+    }
+  }
+}
diff --git a/server/node_modules/signal-exit/package.json b/server/node_modules/signal-exit/package.json
new file mode 100644
index 0000000..e1a0031
--- /dev/null
+++ b/server/node_modules/signal-exit/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "signal-exit",
+  "version": "3.0.7",
+  "description": "when you want to fire an event no matter how a process exits.",
+  "main": "index.js",
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags"
+  },
+  "files": [
+    "index.js",
+    "signals.js"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/tapjs/signal-exit.git"
+  },
+  "keywords": [
+    "signal",
+    "exit"
+  ],
+  "author": "Ben Coe <ben@npmjs.com>",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/tapjs/signal-exit/issues"
+  },
+  "homepage": "https://github.com/tapjs/signal-exit",
+  "devDependencies": {
+    "chai": "^3.5.0",
+    "coveralls": "^3.1.1",
+    "nyc": "^15.1.0",
+    "standard-version": "^9.3.1",
+    "tap": "^15.1.1"
+  }
+}
diff --git a/server/node_modules/signal-exit/signals.js b/server/node_modules/signal-exit/signals.js
new file mode 100644
index 0000000..3bd67a8
--- /dev/null
+++ b/server/node_modules/signal-exit/signals.js
@@ -0,0 +1,53 @@
+// This is not the set of all possible signals.
+//
+// It IS, however, the set of all signals that trigger
+// an exit on either Linux or BSD systems.  Linux is a
+// superset of the signal names supported on BSD, and
+// the unknown signals just fail to register, so we can
+// catch that easily enough.
+//
+// Don't bother with SIGKILL.  It's uncatchable, which
+// means that we can't fire any callbacks anyway.
+//
+// If a user does happen to register a handler on a non-
+// fatal signal like SIGWINCH or something, and then
+// exit, it'll end up firing `process.emit('exit')`, so
+// the handler will be fired anyway.
+//
+// SIGBUS, SIGFPE, SIGSEGV and SIGILL, when not raised
+// artificially, inherently leave the process in a
+// state from which it is not safe to try and enter JS
+// listeners.
+module.exports = [
+  'SIGABRT',
+  'SIGALRM',
+  'SIGHUP',
+  'SIGINT',
+  'SIGTERM'
+]
+
+if (process.platform !== 'win32') {
+  module.exports.push(
+    'SIGVTALRM',
+    'SIGXCPU',
+    'SIGXFSZ',
+    'SIGUSR2',
+    'SIGTRAP',
+    'SIGSYS',
+    'SIGQUIT',
+    'SIGIOT'
+    // should detect profiler and enable/disable accordingly.
+    // see #21
+    // 'SIGPROF'
+  )
+}
+
+if (process.platform === 'linux') {
+  module.exports.push(
+    'SIGIO',
+    'SIGPOLL',
+    'SIGPWR',
+    'SIGSTKFLT',
+    'SIGUNUSED'
+  )
+}
diff --git a/server/node_modules/simple-concat/.travis.yml b/server/node_modules/simple-concat/.travis.yml
new file mode 100644
index 0000000..c159f6a
--- /dev/null
+++ b/server/node_modules/simple-concat/.travis.yml
@@ -0,0 +1,3 @@
+language: node_js
+node_js:
+  - lts/*
diff --git a/server/node_modules/simple-concat/LICENSE b/server/node_modules/simple-concat/LICENSE
new file mode 100644
index 0000000..c7e6852
--- /dev/null
+++ b/server/node_modules/simple-concat/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) Feross Aboukhadijeh
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/simple-concat/README.md b/server/node_modules/simple-concat/README.md
new file mode 100644
index 0000000..b7d39bd
--- /dev/null
+++ b/server/node_modules/simple-concat/README.md
@@ -0,0 +1,44 @@
+# simple-concat [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![downloads][downloads-image]][downloads-url] [![javascript style guide][standard-image]][standard-url]
+
+[travis-image]: https://img.shields.io/travis/feross/simple-concat/master.svg
+[travis-url]: https://travis-ci.org/feross/simple-concat
+[npm-image]: https://img.shields.io/npm/v/simple-concat.svg
+[npm-url]: https://npmjs.org/package/simple-concat
+[downloads-image]: https://img.shields.io/npm/dm/simple-concat.svg
+[downloads-url]: https://npmjs.org/package/simple-concat
+[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
+[standard-url]: https://standardjs.com
+
+### Super-minimalist version of [`concat-stream`](https://github.com/maxogden/concat-stream). Less than 15 lines!
+
+## install
+
+```
+npm install simple-concat
+```
+
+## usage
+
+This example is longer than the implementation.
+
+```js
+var s = new stream.PassThrough()
+concat(s, function (err, buf) {
+  if (err) throw err
+  console.error(buf)
+})
+s.write('abc')
+setTimeout(function () {
+  s.write('123')
+}, 10)
+setTimeout(function () {
+  s.write('456')
+}, 20)
+setTimeout(function () {
+  s.end('789')
+}, 30)
+```
+
+## license
+
+MIT. Copyright (c) [Feross Aboukhadijeh](http://feross.org).
diff --git a/server/node_modules/simple-concat/index.js b/server/node_modules/simple-concat/index.js
new file mode 100644
index 0000000..59237fc
--- /dev/null
+++ b/server/node_modules/simple-concat/index.js
@@ -0,0 +1,15 @@
+/*! simple-concat. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
+module.exports = function (stream, cb) {
+  var chunks = []
+  stream.on('data', function (chunk) {
+    chunks.push(chunk)
+  })
+  stream.once('end', function () {
+    if (cb) cb(null, Buffer.concat(chunks))
+    cb = null
+  })
+  stream.once('error', function (err) {
+    if (cb) cb(err)
+    cb = null
+  })
+}
diff --git a/server/node_modules/simple-concat/package.json b/server/node_modules/simple-concat/package.json
new file mode 100644
index 0000000..2bb2c60
--- /dev/null
+++ b/server/node_modules/simple-concat/package.json
@@ -0,0 +1,47 @@
+{
+  "name": "simple-concat",
+  "description": "Super-minimalist version of `concat-stream`. Less than 15 lines!",
+  "version": "1.0.1",
+  "author": {
+    "name": "Feross Aboukhadijeh",
+    "email": "feross@feross.org",
+    "url": "https://feross.org"
+  },
+  "bugs": {
+    "url": "https://github.com/feross/simple-concat/issues"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "standard": "*",
+    "tape": "^5.0.1"
+  },
+  "homepage": "https://github.com/feross/simple-concat",
+  "keywords": [
+    "concat",
+    "concat-stream",
+    "concat stream"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/feross/simple-concat.git"
+  },
+  "scripts": {
+    "test": "standard && tape test/*.js"
+  },
+  "funding": [
+    {
+      "type": "github",
+      "url": "https://github.com/sponsors/feross"
+    },
+    {
+      "type": "patreon",
+      "url": "https://www.patreon.com/feross"
+    },
+    {
+      "type": "consulting",
+      "url": "https://feross.org/support"
+    }
+  ]
+}
diff --git a/server/node_modules/simple-concat/test/basic.js b/server/node_modules/simple-concat/test/basic.js
new file mode 100644
index 0000000..4bf6f9c
--- /dev/null
+++ b/server/node_modules/simple-concat/test/basic.js
@@ -0,0 +1,41 @@
+var concat = require('../')
+var stream = require('stream')
+var test = require('tape')
+
+test('basic', function (t) {
+  t.plan(2)
+  var s = new stream.PassThrough()
+  concat(s, function (err, buf) {
+    t.error(err)
+    t.deepEqual(buf, Buffer.from('abc123456789'))
+  })
+  s.write('abc')
+  setTimeout(function () {
+    s.write('123')
+  }, 10)
+  setTimeout(function () {
+    s.write('456')
+  }, 20)
+  setTimeout(function () {
+    s.end('789')
+  }, 30)
+})
+
+test('error', function (t) {
+  t.plan(2)
+  var s = new stream.PassThrough()
+  concat(s, function (err, buf) {
+    t.ok(err, 'got expected error')
+    t.ok(!buf)
+  })
+  s.write('abc')
+  setTimeout(function () {
+    s.write('123')
+  }, 10)
+  setTimeout(function () {
+    s.write('456')
+  }, 20)
+  setTimeout(function () {
+    s.emit('error', new Error('error'))
+  }, 30)
+})
diff --git a/server/node_modules/simple-get/.github/dependabot.yml b/server/node_modules/simple-get/.github/dependabot.yml
new file mode 100644
index 0000000..0221fbc
--- /dev/null
+++ b/server/node_modules/simple-get/.github/dependabot.yml
@@ -0,0 +1,15 @@
+version: 2
+updates:
+  - package-ecosystem: npm
+    directory: /
+    schedule:
+      interval: daily
+    labels:
+      - dependency
+    versioning-strategy: increase-if-necessary
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: daily
+    labels:
+      - dependency
diff --git a/server/node_modules/simple-get/.github/workflows/ci.yml b/server/node_modules/simple-get/.github/workflows/ci.yml
new file mode 100644
index 0000000..822d21c
--- /dev/null
+++ b/server/node_modules/simple-get/.github/workflows/ci.yml
@@ -0,0 +1,23 @@
+name: ci
+'on':
+  - push
+  - pull_request
+jobs:
+  test:
+    name: Node ${{ matrix.node }} / ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+        node:
+          - '14'
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: ${{ matrix.node }}
+      - run: npm install
+      - run: npm run build --if-present
+      - run: npm test
diff --git a/server/node_modules/simple-get/LICENSE b/server/node_modules/simple-get/LICENSE
new file mode 100644
index 0000000..c7e6852
--- /dev/null
+++ b/server/node_modules/simple-get/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) Feross Aboukhadijeh
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/simple-get/README.md b/server/node_modules/simple-get/README.md
new file mode 100644
index 0000000..63c6a6b
--- /dev/null
+++ b/server/node_modules/simple-get/README.md
@@ -0,0 +1,333 @@
+# simple-get [![ci][ci-image]][ci-url] [![npm][npm-image]][npm-url] [![downloads][downloads-image]][downloads-url] [![javascript style guide][standard-image]][standard-url]
+
+[ci-image]: https://img.shields.io/github/workflow/status/feross/simple-get/ci/master
+[ci-url]: https://github.com/feross/simple-get/actions
+[npm-image]: https://img.shields.io/npm/v/simple-get.svg
+[npm-url]: https://npmjs.org/package/simple-get
+[downloads-image]: https://img.shields.io/npm/dm/simple-get.svg
+[downloads-url]: https://npmjs.org/package/simple-get
+[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
+[standard-url]: https://standardjs.com
+
+### Simplest way to make http get requests
+
+## features
+
+This module is the lightest possible wrapper on top of node.js `http`, but supporting these essential features:
+
+- follows redirects
+- automatically handles gzip/deflate responses
+- supports HTTPS
+- supports specifying a timeout
+- supports convenience `url` key so there's no need to use `url.parse` on the url when specifying options
+- composes well with npm packages for features like cookies, proxies, form data, & OAuth
+
+All this in < 100 lines of code.
+
+## install
+
+```
+npm install simple-get
+```
+
+## usage
+
+Note, all these examples also work in the browser with [browserify](http://browserify.org/).
+
+### simple GET request
+
+Doesn't get easier than this:
+
+```js
+const get = require('simple-get')
+
+get('http://example.com', function (err, res) {
+  if (err) throw err
+  console.log(res.statusCode) // 200
+  res.pipe(process.stdout) // `res` is a stream
+})
+```
+
+### even simpler GET request
+
+If you just want the data, and don't want to deal with streams:
+
+```js
+const get = require('simple-get')
+
+get.concat('http://example.com', function (err, res, data) {
+  if (err) throw err
+  console.log(res.statusCode) // 200
+  console.log(data) // Buffer('this is the server response')
+})
+```
+
+### POST, PUT, PATCH, HEAD, DELETE support
+
+For `POST`, call `get.post` or use option `{ method: 'POST' }`.
+
+```js
+const get = require('simple-get')
+
+const opts = {
+  url: 'http://example.com',
+  body: 'this is the POST body'
+}
+get.post(opts, function (err, res) {
+  if (err) throw err
+  res.pipe(process.stdout) // `res` is a stream
+})
+```
+
+#### A more complex example:
+
+```js
+const get = require('simple-get')
+
+get({
+  url: 'http://example.com',
+  method: 'POST',
+  body: 'this is the POST body',
+
+  // simple-get accepts all options that node.js `http` accepts
+  // See: http://nodejs.org/api/http.html#http_http_request_options_callback
+  headers: {
+    'user-agent': 'my cool app'
+  }
+}, function (err, res) {
+  if (err) throw err
+
+  // All properties/methods from http.IncomingResponse are available,
+  // even if a gunzip/inflate transform stream was returned.
+  // See: http://nodejs.org/api/http.html#http_http_incomingmessage
+  res.setTimeout(10000)
+  console.log(res.headers)
+
+  res.on('data', function (chunk) {
+    // `chunk` is the decoded response, after it's been gunzipped or inflated
+    // (if applicable)
+    console.log('got a chunk of the response: ' + chunk)
+  }))
+
+})
+```
+
+### JSON
+
+You can serialize/deserialize request and response with JSON:
+
+```js
+const get = require('simple-get')
+
+const opts = {
+  method: 'POST',
+  url: 'http://example.com',
+  body: {
+    key: 'value'
+  },
+  json: true
+}
+get.concat(opts, function (err, res, data) {
+  if (err) throw err
+  console.log(data.key) // `data` is an object
+})
+```
+
+### Timeout
+
+You can set a timeout (in milliseconds) on the request with the `timeout` option.
+If the request takes longer than `timeout` to complete, then the entire request
+will fail with an `Error`.
+
+```js
+const get = require('simple-get')
+
+const opts = {
+  url: 'http://example.com',
+  timeout: 2000 // 2 second timeout
+}
+
+get(opts, function (err, res) {})
+```
+
+### One Quick Tip
+
+It's a good idea to set the `'user-agent'` header so the provider can more easily
+see how their resource is used.
+
+```js
+const get = require('simple-get')
+const pkg = require('./package.json')
+
+get('http://example.com', {
+  headers: {
+    'user-agent': `my-module/${pkg.version} (https://github.com/username/my-module)`
+  }
+})
+```
+
+### Proxies
+
+You can use the [`tunnel`](https://github.com/koichik/node-tunnel) module with the
+`agent` option to work with proxies:
+
+```js
+const get = require('simple-get')
+const tunnel = require('tunnel')
+
+const opts = {
+  url: 'http://example.com',
+  agent: tunnel.httpOverHttp({
+    proxy: {
+      host: 'localhost'
+    }
+  })
+}
+
+get(opts, function (err, res) {})
+```
+
+### Cookies
+
+You can use the [`cookie`](https://github.com/jshttp/cookie) module to include
+cookies in a request:
+
+```js
+const get = require('simple-get')
+const cookie = require('cookie')
+
+const opts = {
+  url: 'http://example.com',
+  headers: {
+    cookie: cookie.serialize('foo', 'bar')
+  }
+}
+
+get(opts, function (err, res) {})
+```
+
+### Form data
+
+You can use the [`form-data`](https://github.com/form-data/form-data) module to
+create POST request with form data:
+
+```js
+const fs = require('fs')
+const get = require('simple-get')
+const FormData = require('form-data')
+const form = new FormData()
+
+form.append('my_file', fs.createReadStream('/foo/bar.jpg'))
+
+const opts = {
+  url: 'http://example.com',
+  body: form
+}
+
+get.post(opts, function (err, res) {})
+```
+
+#### Or, include `application/x-www-form-urlencoded` form data manually:
+
+```js
+const get = require('simple-get')
+
+const opts = {
+  url: 'http://example.com',
+  form: {
+    key: 'value'
+  }
+}
+get.post(opts, function (err, res) {})
+```
+
+### Specifically disallowing redirects
+
+```js
+const get = require('simple-get')
+
+const opts = {
+  url: 'http://example.com/will-redirect-elsewhere',
+  followRedirects: false
+}
+// res.statusCode will be 301, no error thrown
+get(opts, function (err, res) {})
+```
+
+### Basic Auth
+
+```js
+const user = 'someuser'
+const pass = 'pa$$word'
+const encodedAuth = Buffer.from(`${user}:${pass}`).toString('base64')
+
+get('http://example.com', {
+  headers: {
+    authorization: `Basic ${encodedAuth}`
+  }
+})
+```
+
+### OAuth
+
+You can use the [`oauth-1.0a`](https://github.com/ddo/oauth-1.0a) module to create
+a signed OAuth request:
+
+```js
+const get = require('simple-get')
+const crypto  = require('crypto')
+const OAuth = require('oauth-1.0a')
+
+const oauth = OAuth({
+  consumer: {
+    key: process.env.CONSUMER_KEY,
+    secret: process.env.CONSUMER_SECRET
+  },
+  signature_method: 'HMAC-SHA1',
+  hash_function: (baseString, key) => crypto.createHmac('sha1', key).update(baseString).digest('base64')
+})
+
+const token = {
+  key: process.env.ACCESS_TOKEN,
+  secret: process.env.ACCESS_TOKEN_SECRET
+}
+
+const url = 'https://api.twitter.com/1.1/statuses/home_timeline.json'
+
+const opts = {
+  url: url,
+  headers: oauth.toHeader(oauth.authorize({url, method: 'GET'}, token)),
+  json: true
+}
+
+get(opts, function (err, res) {})
+```
+
+### Throttle requests
+
+You can use [limiter](https://github.com/jhurliman/node-rate-limiter) to throttle requests. This is useful when calling an API that is rate limited.
+
+```js
+const simpleGet = require('simple-get')
+const RateLimiter = require('limiter').RateLimiter
+const limiter = new RateLimiter(1, 'second')
+
+const get = (opts, cb) => limiter.removeTokens(1, () => simpleGet(opts, cb))
+get.concat = (opts, cb) => limiter.removeTokens(1, () => simpleGet.concat(opts, cb))
+
+var opts = {
+  url: 'http://example.com'
+}
+
+get.concat(opts, processResult)
+get.concat(opts, processResult)
+
+function processResult (err, res, data) {
+  if (err) throw err
+  console.log(data.toString())
+}
+```
+
+## license
+
+MIT. Copyright (c) [Feross Aboukhadijeh](http://feross.org).
diff --git a/server/node_modules/simple-get/index.js b/server/node_modules/simple-get/index.js
new file mode 100644
index 0000000..80e52e8
--- /dev/null
+++ b/server/node_modules/simple-get/index.js
@@ -0,0 +1,108 @@
+/*! simple-get. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
+module.exports = simpleGet
+
+const concat = require('simple-concat')
+const decompressResponse = require('decompress-response') // excluded from browser build
+const http = require('http')
+const https = require('https')
+const once = require('once')
+const querystring = require('querystring')
+const url = require('url')
+
+const isStream = o => o !== null && typeof o === 'object' && typeof o.pipe === 'function'
+
+function simpleGet (opts, cb) {
+  opts = Object.assign({ maxRedirects: 10 }, typeof opts === 'string' ? { url: opts } : opts)
+  cb = once(cb)
+
+  if (opts.url) {
+    const { hostname, port, protocol, auth, path } = url.parse(opts.url) // eslint-disable-line node/no-deprecated-api
+    delete opts.url
+    if (!hostname && !port && !protocol && !auth) opts.path = path // Relative redirect
+    else Object.assign(opts, { hostname, port, protocol, auth, path }) // Absolute redirect
+  }
+
+  const headers = { 'accept-encoding': 'gzip, deflate' }
+  if (opts.headers) Object.keys(opts.headers).forEach(k => (headers[k.toLowerCase()] = opts.headers[k]))
+  opts.headers = headers
+
+  let body
+  if (opts.body) {
+    body = opts.json && !isStream(opts.body) ? JSON.stringify(opts.body) : opts.body
+  } else if (opts.form) {
+    body = typeof opts.form === 'string' ? opts.form : querystring.stringify(opts.form)
+    opts.headers['content-type'] = 'application/x-www-form-urlencoded'
+  }
+
+  if (body) {
+    if (!opts.method) opts.method = 'POST'
+    if (!isStream(body)) opts.headers['content-length'] = Buffer.byteLength(body)
+    if (opts.json && !opts.form) opts.headers['content-type'] = 'application/json'
+  }
+  delete opts.body; delete opts.form
+
+  if (opts.json) opts.headers.accept = 'application/json'
+  if (opts.method) opts.method = opts.method.toUpperCase()
+
+  const originalHost = opts.hostname // hostname before potential redirect
+  const protocol = opts.protocol === 'https:' ? https : http // Support http/https urls
+  const req = protocol.request(opts, res => {
+    if (opts.followRedirects !== false && res.statusCode >= 300 && res.statusCode < 400 && res.headers.location) {
+      opts.url = res.headers.location // Follow 3xx redirects
+      delete opts.headers.host // Discard `host` header on redirect (see #32)
+      res.resume() // Discard response
+
+      const redirectHost = url.parse(opts.url).hostname // eslint-disable-line node/no-deprecated-api
+      // If redirected host is different than original host, drop headers to prevent cookie leak (#73)
+      if (redirectHost !== null && redirectHost !== originalHost) {
+        delete opts.headers.cookie
+        delete opts.headers.authorization
+      }
+
+      if (opts.method === 'POST' && [301, 302].includes(res.statusCode)) {
+        opts.method = 'GET' // On 301/302 redirect, change POST to GET (see #35)
+        delete opts.headers['content-length']; delete opts.headers['content-type']
+      }
+
+      if (opts.maxRedirects-- === 0) return cb(new Error('too many redirects'))
+      else return simpleGet(opts, cb)
+    }
+
+    const tryUnzip = typeof decompressResponse === 'function' && opts.method !== 'HEAD'
+    cb(null, tryUnzip ? decompressResponse(res) : res)
+  })
+  req.on('timeout', () => {
+    req.abort()
+    cb(new Error('Request timed out'))
+  })
+  req.on('error', cb)
+
+  if (isStream(body)) body.on('error', cb).pipe(req)
+  else req.end(body)
+
+  return req
+}
+
+simpleGet.concat = (opts, cb) => {
+  return simpleGet(opts, (err, res) => {
+    if (err) return cb(err)
+    concat(res, (err, data) => {
+      if (err) return cb(err)
+      if (opts.json) {
+        try {
+          data = JSON.parse(data.toString())
+        } catch (err) {
+          return cb(err, res, data)
+        }
+      }
+      cb(null, res, data)
+    })
+  })
+}
+
+;['get', 'post', 'put', 'patch', 'head', 'delete'].forEach(method => {
+  simpleGet[method] = (opts, cb) => {
+    if (typeof opts === 'string') opts = { url: opts }
+    return simpleGet(Object.assign({ method: method.toUpperCase() }, opts), cb)
+  }
+})
diff --git a/server/node_modules/simple-get/package.json b/server/node_modules/simple-get/package.json
new file mode 100644
index 0000000..e80fc5e
--- /dev/null
+++ b/server/node_modules/simple-get/package.json
@@ -0,0 +1,67 @@
+{
+  "name": "simple-get",
+  "description": "Simplest way to make http get requests. Supports HTTPS, redirects, gzip/deflate, streams in < 100 lines.",
+  "version": "4.0.1",
+  "author": {
+    "name": "Feross Aboukhadijeh",
+    "email": "feross@feross.org",
+    "url": "https://feross.org"
+  },
+  "browser": {
+    "decompress-response": false
+  },
+  "bugs": {
+    "url": "https://github.com/feross/simple-get/issues"
+  },
+  "dependencies": {
+    "decompress-response": "^6.0.0",
+    "once": "^1.3.1",
+    "simple-concat": "^1.0.0"
+  },
+  "devDependencies": {
+    "self-signed-https": "^1.0.5",
+    "standard": "*",
+    "string-to-stream": "^3.0.0",
+    "tape": "^5.0.0"
+  },
+  "homepage": "https://github.com/feross/simple-get",
+  "keywords": [
+    "request",
+    "http",
+    "GET",
+    "get request",
+    "http.get",
+    "redirects",
+    "follow redirects",
+    "gzip",
+    "deflate",
+    "https",
+    "http-https",
+    "stream",
+    "simple request",
+    "simple get"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/feross/simple-get.git"
+  },
+  "scripts": {
+    "test": "standard && tape test/*.js"
+  },
+  "funding": [
+    {
+      "type": "github",
+      "url": "https://github.com/sponsors/feross"
+    },
+    {
+      "type": "patreon",
+      "url": "https://www.patreon.com/feross"
+    },
+    {
+      "type": "consulting",
+      "url": "https://feross.org/support"
+    }
+  ]
+}
diff --git a/server/node_modules/smart-buffer/.prettierrc.yaml b/server/node_modules/smart-buffer/.prettierrc.yaml
new file mode 100644
index 0000000..9a4f5ed
--- /dev/null
+++ b/server/node_modules/smart-buffer/.prettierrc.yaml
@@ -0,0 +1,5 @@
+parser: typescript
+printWidth: 120
+tabWidth: 2
+singleQuote: true
+trailingComma: none
\ No newline at end of file
diff --git a/server/node_modules/smart-buffer/.travis.yml b/server/node_modules/smart-buffer/.travis.yml
new file mode 100644
index 0000000..eec71ce
--- /dev/null
+++ b/server/node_modules/smart-buffer/.travis.yml
@@ -0,0 +1,13 @@
+language: node_js
+node_js:
+  - 6
+  - 8
+  - 10
+  - 12
+  - stable
+
+before_script:
+  - npm install -g typescript
+  - tsc -p ./
+
+script: "npm run coveralls"
\ No newline at end of file
diff --git a/server/node_modules/smart-buffer/LICENSE b/server/node_modules/smart-buffer/LICENSE
new file mode 100644
index 0000000..aab5771
--- /dev/null
+++ b/server/node_modules/smart-buffer/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2013-2017 Josh Glazebrook
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/smart-buffer/README.md b/server/node_modules/smart-buffer/README.md
new file mode 100644
index 0000000..6e49828
--- /dev/null
+++ b/server/node_modules/smart-buffer/README.md
@@ -0,0 +1,633 @@
+smart-buffer  [![Build Status](https://travis-ci.org/JoshGlazebrook/smart-buffer.svg?branch=master)](https://travis-ci.org/JoshGlazebrook/smart-buffer)  [![Coverage Status](https://coveralls.io/repos/github/JoshGlazebrook/smart-buffer/badge.svg?branch=master)](https://coveralls.io/github/JoshGlazebrook/smart-buffer?branch=master)
+=============
+
+smart-buffer is a Buffer wrapper that adds automatic read & write offset tracking, string operations, data insertions, and more.
+
+![stats](https://nodei.co/npm/smart-buffer.png?downloads=true&downloadRank=true&stars=true "stats")
+
+**Key Features**:
+* Proxies all of the Buffer write and read functions
+* Keeps track of read and write offsets automatically
+* Grows the internal Buffer as needed
+* Useful string operations. (Null terminating strings)
+* Allows for inserting values at specific points in the Buffer
+* Built in TypeScript
+* Type Definitions Provided
+* Browser Support (using Webpack/Browserify)
+* Full test coverage
+
+**Requirements**:
+* Node v4.0+ is supported at this time.  (Versions prior to 2.0 will work on node 0.10)
+
+
+
+## Breaking Changes in v4.0
+
+* Old constructor patterns have been completely removed. It's now required to use the SmartBuffer.fromXXX() factory constructors.
+* rewind(), skip(), moveTo() have been removed. (see [offsets](#offsets))
+* Internal private properties are now prefixed with underscores (_)
+* **All** writeXXX() methods that are given an offset will now **overwrite data** instead of insert. (see [write vs insert](#write-vs-insert))
+* insertXXX() methods have been added for when you want to insert data at a specific offset (this replaces the old behavior of writeXXX() when an offset was provided)
+
+
+## Looking for v3 docs?
+
+Legacy documentation for version 3 and prior can be found [here](https://github.com/JoshGlazebrook/smart-buffer/blob/master/docs/README_v3.md).
+
+## Installing:
+
+`yarn add smart-buffer`
+
+or
+
+`npm install smart-buffer`
+
+Note: The published NPM package includes the built javascript library.
+If you cloned this repo and wish to build the library manually use:
+
+`npm run build`
+
+## Using smart-buffer
+
+```javascript
+// Javascript
+const SmartBuffer = require('smart-buffer').SmartBuffer;
+
+// Typescript
+import { SmartBuffer, SmartBufferOptions} from 'smart-buffer';
+```
+
+### Simple Example
+
+Building a packet that uses the following protocol specification:
+
+`[PacketType:2][PacketLength:2][Data:XX]`
+
+To build this packet using the vanilla Buffer class, you would have to count up the length of the data payload beforehand. You would also need to keep track of the current "cursor" position in your Buffer so you write everything in the right places. With smart-buffer you don't have to do either of those things.
+
+```javascript
+function createLoginPacket(username, password, age, country) {
+    const packet = new SmartBuffer();
+    packet.writeUInt16LE(0x0060); // Some packet type
+    packet.writeStringNT(username);
+    packet.writeStringNT(password);
+    packet.writeUInt8(age);
+    packet.writeStringNT(country);
+    packet.insertUInt16LE(packet.length - 2, 2);
+
+    return packet.toBuffer();
+}
+```
+With the above function, you now can do this:
+```javascript
+const login = createLoginPacket("Josh", "secret123", 22, "United States");
+
+// <Buffer 60 00 1e 00 4a 6f 73 68 00 73 65 63 72 65 74 31 32 33 00 16 55 6e 69 74 65 64 20 53 74 61 74 65 73 00>
+```
+Notice that the `[PacketLength:2]` value (1e 00) was inserted at position 2.
+
+Reading back the packet we created above is just as easy:
+```javascript
+
+const reader = SmartBuffer.fromBuffer(login);
+
+const logininfo = {
+    packetType: reader.readUInt16LE(),
+    packetLength: reader.readUInt16LE(),
+    username: reader.readStringNT(),
+    password: reader.readStringNT(),
+    age: reader.readUInt8(),
+    country: reader.readStringNT()
+};
+
+/*
+{
+    packetType: 96, (0x0060)
+    packetLength: 30,
+    username: 'Josh',
+    password: 'secret123',
+    age: 22,
+    country: 'United States'
+}
+*/
+```
+
+
+## Write vs Insert
+In prior versions of SmartBuffer, .writeXXX(value, offset) calls would insert data when an offset was provided. In version 4, this will now overwrite the data at the offset position. To insert data there are now corresponding .insertXXX(value, offset) methods.
+
+**SmartBuffer v3**:
+```javascript
+const buff = SmartBuffer.fromBuffer(new Buffer([1,2,3,4,5,6]));
+buff.writeInt8(7, 2);
+console.log(buff.toBuffer())
+
+// <Buffer 01 02 07 03 04 05 06>
+```
+
+**SmartBuffer v4**:
+```javascript
+const buff = SmartBuffer.fromBuffer(new Buffer([1,2,3,4,5,6]));
+buff.writeInt8(7, 2);
+console.log(buff.toBuffer());
+
+// <Buffer 01 02 07 04 05 06>
+```
+
+To insert you instead should use:
+```javascript
+const buff = SmartBuffer.fromBuffer(new Buffer([1,2,3,4,5,6]));
+buff.insertInt8(7, 2);
+console.log(buff.toBuffer());
+
+// <Buffer 01 02 07 03 04 05 06>
+```
+
+**Note:** Insert/Writing to a position beyond the currently tracked internal Buffer will zero pad to your offset.
+
+## Constructing a smart-buffer
+
+There are a few different ways to construct a SmartBuffer instance.
+
+```javascript
+// Creating SmartBuffer from existing Buffer
+const buff = SmartBuffer.fromBuffer(buffer); // Creates instance from buffer. (Uses default utf8 encoding)
+const buff = SmartBuffer.fromBuffer(buffer, 'ascii'); // Creates instance from buffer with ascii encoding for strings.
+
+// Creating SmartBuffer with specified internal Buffer size. (Note: this is not a hard cap, the internal buffer will grow as needed).
+const buff = SmartBuffer.fromSize(1024); // Creates instance with internal Buffer size of 1024.
+const buff = SmartBuffer.fromSize(1024, 'utf8'); // Creates instance with internal Buffer size of 1024, and utf8 encoding for strings.
+
+// Creating SmartBuffer with options object. This one specifies size and encoding.
+const buff = SmartBuffer.fromOptions({
+    size: 1024,
+    encoding: 'ascii'
+});
+
+// Creating SmartBuffer with options object. This one specified an existing Buffer.
+const buff = SmartBuffer.fromOptions({
+    buff: buffer
+});
+
+// Creating SmartBuffer from a string.
+const buff = SmartBuffer.fromBuffer(Buffer.from('some string', 'utf8'));
+
+// Just want a regular SmartBuffer with all default options?
+const buff = new SmartBuffer();
+```
+
+# Api Reference:
+
+**Note:** SmartBuffer is fully documented with Typescript definitions as well as jsdocs so your favorite editor/IDE will have intellisense.
+
+**Table of Contents**
+
+1. [Constructing](#constructing)
+2. **Numbers**
+    1. [Integers](#integers)
+    2. [Floating Points](#floating-point-numbers)
+3. **Strings**
+    1. [Strings](#strings)
+    2. [Null Terminated Strings](#null-terminated-strings)
+4. [Buffers](#buffers)
+5. [Offsets](#offsets)
+6. [Other](#other)
+
+
+## Constructing
+
+### constructor()
+### constructor([options])
+- ```options``` *{SmartBufferOptions}* An optional options object to construct a SmartBuffer with.
+
+Examples:
+```javascript
+const buff = new SmartBuffer();
+const buff = new SmartBuffer({
+    size: 1024,
+    encoding: 'ascii'
+});
+```
+
+### Class Method: fromBuffer(buffer[, encoding])
+- ```buffer``` *{Buffer}* The Buffer instance to wrap.
+- ```encoding``` *{string}* The string encoding to use. ```Default: 'utf8'```
+
+Examples:
+```javascript
+const someBuffer = Buffer.from('some string');
+const buff = SmartBuffer.fromBuffer(someBuffer); // Defaults to utf8
+const buff = SmartBuffer.fromBuffer(someBuffer, 'ascii');
+```
+
+### Class Method: fromSize(size[, encoding])
+- ```size``` *{number}* The size to initialize the internal Buffer.
+- ```encoding``` *{string}* The string encoding to use. ```Default: 'utf8'```
+
+Examples:
+```javascript
+const buff = SmartBuffer.fromSize(1024); // Defaults to utf8
+const buff = SmartBuffer.fromSize(1024, 'ascii');
+```
+
+### Class Method: fromOptions(options)
+- ```options``` *{SmartBufferOptions}* The Buffer instance to wrap.
+
+```typescript
+interface SmartBufferOptions {
+    encoding?: BufferEncoding; // Defaults to utf8
+    size?: number; // Defaults to 4096
+    buff?: Buffer;
+}
+```
+
+Examples:
+```javascript
+const buff = SmartBuffer.fromOptions({
+    size: 1024
+};
+const buff = SmartBuffer.fromOptions({
+    size: 1024,
+    encoding: 'utf8'
+});
+const buff = SmartBuffer.fromOptions({
+    encoding: 'utf8'
+});
+
+const someBuff = Buffer.from('some string', 'utf8');
+const buff = SmartBuffer.fromOptions({
+    buffer: someBuff,
+    encoding: 'utf8'
+});
+```
+
+## Integers
+
+### buff.readInt8([offset])
+### buff.readUInt8([offset])
+- ```offset``` *{number}* Optional position to start reading data from. **Default**: ```Auto managed offset```
+- Returns *{number}*
+
+Read a Int8 value.
+
+### buff.readInt16BE([offset])
+### buff.readInt16LE([offset])
+### buff.readUInt16BE([offset])
+### buff.readUInt16LE([offset])
+- ```offset``` *{number}* Optional position to start reading data from. **Default**: ```Auto managed offset```
+- Returns *{number}*
+
+Read a 16 bit integer value.
+
+### buff.readInt32BE([offset])
+### buff.readInt32LE([offset])
+### buff.readUInt32BE([offset])
+### buff.readUInt32LE([offset])
+- ```offset``` *{number}* Optional position to start reading data from. **Default**: ```Auto managed offset```
+- Returns *{number}*
+
+Read a 32 bit integer value.
+
+
+### buff.writeInt8(value[, offset])
+### buff.writeUInt8(value[, offset])
+- ```value``` *{number}* The value to write.
+- ```offset``` *{number}* An optional offset to write this value to. **Default:** ```Auto managed offset```
+- Returns *{this}*
+
+Write a Int8 value.
+
+### buff.insertInt8(value, offset)
+### buff.insertUInt8(value, offset)
+- ```value``` *{number}* The value to insert.
+- ```offset``` *{number}* The offset to insert this data at.
+- Returns *{this}*
+
+Insert a Int8 value.
+
+
+### buff.writeInt16BE(value[, offset])
+### buff.writeInt16LE(value[, offset])
+### buff.writeUInt16BE(value[, offset])
+### buff.writeUInt16LE(value[, offset])
+- ```value``` *{number}* The value to write.
+- ```offset``` *{number}* An optional offset to write this value to. **Default:** ```Auto managed offset```
+- Returns *{this}*
+
+Write a 16 bit integer value.
+
+### buff.insertInt16BE(value, offset)
+### buff.insertInt16LE(value, offset)
+### buff.insertUInt16BE(value, offset)
+### buff.insertUInt16LE(value, offset)
+- ```value``` *{number}* The value to insert.
+- ```offset``` *{number}* The offset to insert this data at.
+- Returns *{this}*
+
+Insert a 16 bit integer value.
+
+
+### buff.writeInt32BE(value[, offset])
+### buff.writeInt32LE(value[, offset])
+### buff.writeUInt32BE(value[, offset])
+### buff.writeUInt32LE(value[, offset])
+- ```value``` *{number}* The value to write.
+- ```offset``` *{number}* An optional offset to write this value to. **Default:** ```Auto managed offset```
+- Returns *{this}*
+
+Write a 32 bit integer value.
+
+### buff.insertInt32BE(value, offset)
+### buff.insertInt32LE(value, offset)
+### buff.insertUInt32BE(value, offset)
+### buff.nsertUInt32LE(value, offset)
+- ```value``` *{number}* The value to insert.
+- ```offset``` *{number}* The offset to insert this data at.
+- Returns *{this}*
+
+Insert a 32 bit integer value.
+
+
+## Floating Point Numbers
+
+### buff.readFloatBE([offset])
+### buff.readFloatLE([offset])
+- ```offset``` *{number}* Optional position to start reading data from. **Default**: ```Auto managed offset```
+- Returns *{number}*
+
+Read a Float value.
+
+### buff.readDoubleBE([offset])
+### buff.readDoubleLE([offset])
+- ```offset``` *{number}* Optional position to start reading data from. **Default**: ```Auto managed offset```
+- Returns *{number}*
+
+Read a Double value.
+
+
+### buff.writeFloatBE(value[, offset])
+### buff.writeFloatLE(value[, offset])
+- ```value``` *{number}* The value to write.
+- ```offset``` *{number}* An optional offset to write this value to. **Default:** ```Auto managed offset```
+- Returns *{this}*
+
+Write a Float value.
+
+### buff.insertFloatBE(value, offset)
+### buff.insertFloatLE(value, offset)
+- ```value``` *{number}* The value to insert.
+- ```offset``` *{number}* The offset to insert this data at.
+- Returns *{this}*
+
+Insert a Float value.
+
+
+### buff.writeDoubleBE(value[, offset])
+### buff.writeDoubleLE(value[, offset])
+- ```value``` *{number}* The value to write.
+- ```offset``` *{number}* An optional offset to write this value to. **Default:** ```Auto managed offset```
+- Returns *{this}*
+
+Write a Double value.
+
+### buff.insertDoubleBE(value, offset)
+### buff.insertDoubleLE(value, offset)
+- ```value``` *{number}* The value to insert.
+- ```offset``` *{number}* The offset to insert this data at.
+- Returns *{this}*
+
+Insert a Double value.
+
+## Strings
+
+### buff.readString()
+### buff.readString(size[, encoding])
+### buff.readString(encoding)
+- ```size``` *{number}* The number of bytes to read. **Default:** ```Reads to the end of the Buffer.```
+- ```encoding``` *{string}* The string encoding to use. **Default:** ```utf8```.
+
+Read a string value.
+
+Examples:
+```javascript
+const buff = SmartBuffer.fromBuffer(Buffer.from('hello there', 'utf8'));
+buff.readString(); // 'hello there'
+buff.readString(2); // 'he'
+buff.readString(2, 'utf8'); // 'he'
+buff.readString('utf8'); // 'hello there'
+```
+
+### buff.writeString(value)
+### buff.writeString(value[, offset])
+### buff.writeString(value[, encoding])
+### buff.writeString(value[, offset[, encoding]])
+- ```value``` *{string}* The string value to write.
+- ```offset``` *{number}* The offset to write this value to. **Default:** ```Auto managed offset```
+- ```encoding``` *{string}* An optional string encoding to use. **Default:** ```utf8```
+
+Write a string value.
+
+Examples:
+```javascript
+buff.writeString('hello'); // Auto managed offset
+buff.writeString('hello', 2);
+buff.writeString('hello', 'utf8') // Auto managed offset
+buff.writeString('hello', 2, 'utf8');
+```
+
+### buff.insertString(value, offset[, encoding])
+- ```value``` *{string}* The string value to write.
+- ```offset``` *{number}* The offset to write this value to.
+- ```encoding``` *{string}* An optional string encoding to use. **Default:** ```utf8```
+
+Insert a string value.
+
+Examples:
+```javascript
+buff.insertString('hello', 2);
+buff.insertString('hello', 2, 'utf8');
+```
+
+## Null Terminated Strings
+
+### buff.readStringNT()
+### buff.readStringNT(encoding)
+- ```encoding``` *{string}* The string encoding to use. **Default:** ```utf8```.
+
+Read a null terminated string value. (If a null is not found, it will read to the end of the Buffer).
+
+Examples:
+```javascript
+const buff = SmartBuffer.fromBuffer(Buffer.from('hello\0 there', 'utf8'));
+buff.readStringNT(); // 'hello'
+
+// If we called this again:
+buff.readStringNT(); // ' there'
+```
+
+### buff.writeStringNT(value)
+### buff.writeStringNT(value[, offset])
+### buff.writeStringNT(value[, encoding])
+### buff.writeStringNT(value[, offset[, encoding]])
+- ```value``` *{string}* The string value to write.
+- ```offset``` *{number}* The offset to write this value to. **Default:** ```Auto managed offset```
+- ```encoding``` *{string}* An optional string encoding to use. **Default:** ```utf8```
+
+Write a null terminated string value.
+
+Examples:
+```javascript
+buff.writeStringNT('hello'); // Auto managed offset   <Buffer 68 65 6c 6c 6f 00>
+buff.writeStringNT('hello', 2); // <Buffer 00 00 68 65 6c 6c 6f 00>
+buff.writeStringNT('hello', 'utf8') // Auto managed offset
+buff.writeStringNT('hello', 2, 'utf8');
+```
+
+### buff.insertStringNT(value, offset[, encoding])
+- ```value``` *{string}* The string value to write.
+- ```offset``` *{number}* The offset to write this value to.
+- ```encoding``` *{string}* An optional string encoding to use. **Default:** ```utf8```
+
+Insert a null terminated string value.
+
+Examples:
+```javascript
+buff.insertStringNT('hello', 2);
+buff.insertStringNT('hello', 2, 'utf8');
+```
+
+## Buffers
+
+### buff.readBuffer([length])
+- ```length``` *{number}* The number of bytes to read into a Buffer. **Default:** ```Reads to the end of the Buffer```
+
+Read a Buffer of a specified size.
+
+### buff.writeBuffer(value[, offset])
+- ```value``` *{Buffer}* The buffer value to write.
+- ```offset``` *{number}* An optional offset to write the value to. **Default:** ```Auto managed offset```
+
+### buff.insertBuffer(value, offset)
+- ```value``` *{Buffer}* The buffer value to write.
+- ```offset``` *{number}* The offset to write the value to.
+
+
+### buff.readBufferNT()
+
+Read a null terminated Buffer.
+
+### buff.writeBufferNT(value[, offset])
+- ```value``` *{Buffer}* The buffer value to write.
+- ```offset``` *{number}* An optional offset to write the value to. **Default:** ```Auto managed offset```
+
+Write a null terminated Buffer.
+
+
+### buff.insertBufferNT(value, offset)
+- ```value``` *{Buffer}* The buffer value to write.
+- ```offset``` *{number}* The offset to write the value to.
+
+Insert a null terminated Buffer.
+
+
+## Offsets
+
+### buff.readOffset
+### buff.readOffset(offset)
+- ```offset``` *{number}* The new read offset value to set.
+- Returns: ```The current read offset```
+
+Gets or sets the current read offset.
+
+Examples:
+```javascript
+const currentOffset = buff.readOffset; // 5
+
+buff.readOffset = 10;
+
+console.log(buff.readOffset) // 10
+```
+
+### buff.writeOffset
+### buff.writeOffset(offset)
+- ```offset``` *{number}* The new write offset value to set.
+- Returns: ```The current write offset```
+
+Gets or sets the current write offset.
+
+Examples:
+```javascript
+const currentOffset = buff.writeOffset; // 5
+
+buff.writeOffset = 10;
+
+console.log(buff.writeOffset) // 10
+```
+
+### buff.encoding
+### buff.encoding(encoding)
+- ```encoding``` *{string}* The new string encoding to set.
+- Returns: ```The current string encoding```
+
+Gets or sets the current string encoding.
+
+Examples:
+```javascript
+const currentEncoding = buff.encoding; // 'utf8'
+
+buff.encoding = 'ascii';
+
+console.log(buff.encoding) // 'ascii'
+```
+
+## Other
+
+### buff.clear()
+
+Clear and resets the SmartBuffer instance.
+
+### buff.remaining()
+- Returns ```Remaining data left to be read```
+
+Gets the number of remaining bytes to be read.
+
+
+### buff.internalBuffer
+- Returns: *{Buffer}*
+
+Gets the internally managed Buffer (Includes unmanaged data).
+
+Examples:
+```javascript
+const buff = SmartBuffer.fromSize(16);
+buff.writeString('hello');
+console.log(buff.InternalBuffer); // <Buffer 68 65 6c 6c 6f 00 00 00 00 00 00 00 00 00 00 00>
+```
+
+### buff.toBuffer()
+- Returns: *{Buffer}*
+
+Gets a sliced Buffer instance of the internally managed Buffer. (Only includes managed data)
+
+Examples:
+```javascript
+const buff = SmartBuffer.fromSize(16);
+buff.writeString('hello');
+console.log(buff.toBuffer()); // <Buffer 68 65 6c 6c 6f>
+```
+
+### buff.toString([encoding])
+- ```encoding``` *{string}* The string encoding to use when converting to a string. **Default:** ```utf8```
+- Returns *{string}*
+
+Gets a string representation of all data in the SmartBuffer.
+
+### buff.destroy()
+
+Destroys the SmartBuffer instance.
+
+
+
+## License
+
+This work is licensed under the [MIT license](http://en.wikipedia.org/wiki/MIT_License).
diff --git a/server/node_modules/smart-buffer/build/smartbuffer.js b/server/node_modules/smart-buffer/build/smartbuffer.js
new file mode 100644
index 0000000..5353ae1
--- /dev/null
+++ b/server/node_modules/smart-buffer/build/smartbuffer.js
@@ -0,0 +1,1233 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const utils_1 = require("./utils");
+// The default Buffer size if one is not provided.
+const DEFAULT_SMARTBUFFER_SIZE = 4096;
+// The default string encoding to use for reading/writing strings.
+const DEFAULT_SMARTBUFFER_ENCODING = 'utf8';
+class SmartBuffer {
+    /**
+     * Creates a new SmartBuffer instance.
+     *
+     * @param options { SmartBufferOptions } The SmartBufferOptions to apply to this instance.
+     */
+    constructor(options) {
+        this.length = 0;
+        this._encoding = DEFAULT_SMARTBUFFER_ENCODING;
+        this._writeOffset = 0;
+        this._readOffset = 0;
+        if (SmartBuffer.isSmartBufferOptions(options)) {
+            // Checks for encoding
+            if (options.encoding) {
+                utils_1.checkEncoding(options.encoding);
+                this._encoding = options.encoding;
+            }
+            // Checks for initial size length
+            if (options.size) {
+                if (utils_1.isFiniteInteger(options.size) && options.size > 0) {
+                    this._buff = Buffer.allocUnsafe(options.size);
+                }
+                else {
+                    throw new Error(utils_1.ERRORS.INVALID_SMARTBUFFER_SIZE);
+                }
+                // Check for initial Buffer
+            }
+            else if (options.buff) {
+                if (Buffer.isBuffer(options.buff)) {
+                    this._buff = options.buff;
+                    this.length = options.buff.length;
+                }
+                else {
+                    throw new Error(utils_1.ERRORS.INVALID_SMARTBUFFER_BUFFER);
+                }
+            }
+            else {
+                this._buff = Buffer.allocUnsafe(DEFAULT_SMARTBUFFER_SIZE);
+            }
+        }
+        else {
+            // If something was passed but it's not a SmartBufferOptions object
+            if (typeof options !== 'undefined') {
+                throw new Error(utils_1.ERRORS.INVALID_SMARTBUFFER_OBJECT);
+            }
+            // Otherwise default to sane options
+            this._buff = Buffer.allocUnsafe(DEFAULT_SMARTBUFFER_SIZE);
+        }
+    }
+    /**
+     * Creates a new SmartBuffer instance with the provided internal Buffer size and optional encoding.
+     *
+     * @param size { Number } The size of the internal Buffer.
+     * @param encoding { String } The BufferEncoding to use for strings.
+     *
+     * @return { SmartBuffer }
+     */
+    static fromSize(size, encoding) {
+        return new this({
+            size: size,
+            encoding: encoding
+        });
+    }
+    /**
+     * Creates a new SmartBuffer instance with the provided Buffer and optional encoding.
+     *
+     * @param buffer { Buffer } The Buffer to use as the internal Buffer value.
+     * @param encoding { String } The BufferEncoding to use for strings.
+     *
+     * @return { SmartBuffer }
+     */
+    static fromBuffer(buff, encoding) {
+        return new this({
+            buff: buff,
+            encoding: encoding
+        });
+    }
+    /**
+     * Creates a new SmartBuffer instance with the provided SmartBufferOptions options.
+     *
+     * @param options { SmartBufferOptions } The options to use when creating the SmartBuffer instance.
+     */
+    static fromOptions(options) {
+        return new this(options);
+    }
+    /**
+     * Type checking function that determines if an object is a SmartBufferOptions object.
+     */
+    static isSmartBufferOptions(options) {
+        const castOptions = options;
+        return (castOptions &&
+            (castOptions.encoding !== undefined || castOptions.size !== undefined || castOptions.buff !== undefined));
+    }
+    // Signed integers
+    /**
+     * Reads an Int8 value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt8(offset) {
+        return this._readNumberValue(Buffer.prototype.readInt8, 1, offset);
+    }
+    /**
+     * Reads an Int16BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt16BE(offset) {
+        return this._readNumberValue(Buffer.prototype.readInt16BE, 2, offset);
+    }
+    /**
+     * Reads an Int16LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt16LE(offset) {
+        return this._readNumberValue(Buffer.prototype.readInt16LE, 2, offset);
+    }
+    /**
+     * Reads an Int32BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt32BE(offset) {
+        return this._readNumberValue(Buffer.prototype.readInt32BE, 4, offset);
+    }
+    /**
+     * Reads an Int32LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt32LE(offset) {
+        return this._readNumberValue(Buffer.prototype.readInt32LE, 4, offset);
+    }
+    /**
+     * Reads a BigInt64BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { BigInt }
+     */
+    readBigInt64BE(offset) {
+        utils_1.bigIntAndBufferInt64Check('readBigInt64BE');
+        return this._readNumberValue(Buffer.prototype.readBigInt64BE, 8, offset);
+    }
+    /**
+     * Reads a BigInt64LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { BigInt }
+     */
+    readBigInt64LE(offset) {
+        utils_1.bigIntAndBufferInt64Check('readBigInt64LE');
+        return this._readNumberValue(Buffer.prototype.readBigInt64LE, 8, offset);
+    }
+    /**
+     * Writes an Int8 value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt8(value, offset) {
+        this._writeNumberValue(Buffer.prototype.writeInt8, 1, value, offset);
+        return this;
+    }
+    /**
+     * Inserts an Int8 value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt8(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeInt8, 1, value, offset);
+    }
+    /**
+     * Writes an Int16BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt16BE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeInt16BE, 2, value, offset);
+    }
+    /**
+     * Inserts an Int16BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt16BE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeInt16BE, 2, value, offset);
+    }
+    /**
+     * Writes an Int16LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt16LE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeInt16LE, 2, value, offset);
+    }
+    /**
+     * Inserts an Int16LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt16LE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeInt16LE, 2, value, offset);
+    }
+    /**
+     * Writes an Int32BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt32BE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeInt32BE, 4, value, offset);
+    }
+    /**
+     * Inserts an Int32BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt32BE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeInt32BE, 4, value, offset);
+    }
+    /**
+     * Writes an Int32LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt32LE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeInt32LE, 4, value, offset);
+    }
+    /**
+     * Inserts an Int32LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt32LE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeInt32LE, 4, value, offset);
+    }
+    /**
+     * Writes a BigInt64BE value to the current write position (or at optional offset).
+     *
+     * @param value { BigInt } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeBigInt64BE(value, offset) {
+        utils_1.bigIntAndBufferInt64Check('writeBigInt64BE');
+        return this._writeNumberValue(Buffer.prototype.writeBigInt64BE, 8, value, offset);
+    }
+    /**
+     * Inserts a BigInt64BE value at the given offset value.
+     *
+     * @param value { BigInt } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertBigInt64BE(value, offset) {
+        utils_1.bigIntAndBufferInt64Check('writeBigInt64BE');
+        return this._insertNumberValue(Buffer.prototype.writeBigInt64BE, 8, value, offset);
+    }
+    /**
+     * Writes a BigInt64LE value to the current write position (or at optional offset).
+     *
+     * @param value { BigInt } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeBigInt64LE(value, offset) {
+        utils_1.bigIntAndBufferInt64Check('writeBigInt64LE');
+        return this._writeNumberValue(Buffer.prototype.writeBigInt64LE, 8, value, offset);
+    }
+    /**
+     * Inserts a Int64LE value at the given offset value.
+     *
+     * @param value { BigInt } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertBigInt64LE(value, offset) {
+        utils_1.bigIntAndBufferInt64Check('writeBigInt64LE');
+        return this._insertNumberValue(Buffer.prototype.writeBigInt64LE, 8, value, offset);
+    }
+    // Unsigned Integers
+    /**
+     * Reads an UInt8 value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt8(offset) {
+        return this._readNumberValue(Buffer.prototype.readUInt8, 1, offset);
+    }
+    /**
+     * Reads an UInt16BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt16BE(offset) {
+        return this._readNumberValue(Buffer.prototype.readUInt16BE, 2, offset);
+    }
+    /**
+     * Reads an UInt16LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt16LE(offset) {
+        return this._readNumberValue(Buffer.prototype.readUInt16LE, 2, offset);
+    }
+    /**
+     * Reads an UInt32BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt32BE(offset) {
+        return this._readNumberValue(Buffer.prototype.readUInt32BE, 4, offset);
+    }
+    /**
+     * Reads an UInt32LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt32LE(offset) {
+        return this._readNumberValue(Buffer.prototype.readUInt32LE, 4, offset);
+    }
+    /**
+     * Reads a BigUInt64BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { BigInt }
+     */
+    readBigUInt64BE(offset) {
+        utils_1.bigIntAndBufferInt64Check('readBigUInt64BE');
+        return this._readNumberValue(Buffer.prototype.readBigUInt64BE, 8, offset);
+    }
+    /**
+     * Reads a BigUInt64LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { BigInt }
+     */
+    readBigUInt64LE(offset) {
+        utils_1.bigIntAndBufferInt64Check('readBigUInt64LE');
+        return this._readNumberValue(Buffer.prototype.readBigUInt64LE, 8, offset);
+    }
+    /**
+     * Writes an UInt8 value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt8(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeUInt8, 1, value, offset);
+    }
+    /**
+     * Inserts an UInt8 value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt8(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeUInt8, 1, value, offset);
+    }
+    /**
+     * Writes an UInt16BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt16BE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeUInt16BE, 2, value, offset);
+    }
+    /**
+     * Inserts an UInt16BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt16BE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeUInt16BE, 2, value, offset);
+    }
+    /**
+     * Writes an UInt16LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt16LE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeUInt16LE, 2, value, offset);
+    }
+    /**
+     * Inserts an UInt16LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt16LE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeUInt16LE, 2, value, offset);
+    }
+    /**
+     * Writes an UInt32BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt32BE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeUInt32BE, 4, value, offset);
+    }
+    /**
+     * Inserts an UInt32BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt32BE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeUInt32BE, 4, value, offset);
+    }
+    /**
+     * Writes an UInt32LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt32LE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeUInt32LE, 4, value, offset);
+    }
+    /**
+     * Inserts an UInt32LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt32LE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeUInt32LE, 4, value, offset);
+    }
+    /**
+     * Writes a BigUInt64BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeBigUInt64BE(value, offset) {
+        utils_1.bigIntAndBufferInt64Check('writeBigUInt64BE');
+        return this._writeNumberValue(Buffer.prototype.writeBigUInt64BE, 8, value, offset);
+    }
+    /**
+     * Inserts a BigUInt64BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertBigUInt64BE(value, offset) {
+        utils_1.bigIntAndBufferInt64Check('writeBigUInt64BE');
+        return this._insertNumberValue(Buffer.prototype.writeBigUInt64BE, 8, value, offset);
+    }
+    /**
+     * Writes a BigUInt64LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeBigUInt64LE(value, offset) {
+        utils_1.bigIntAndBufferInt64Check('writeBigUInt64LE');
+        return this._writeNumberValue(Buffer.prototype.writeBigUInt64LE, 8, value, offset);
+    }
+    /**
+     * Inserts a BigUInt64LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertBigUInt64LE(value, offset) {
+        utils_1.bigIntAndBufferInt64Check('writeBigUInt64LE');
+        return this._insertNumberValue(Buffer.prototype.writeBigUInt64LE, 8, value, offset);
+    }
+    // Floating Point
+    /**
+     * Reads an FloatBE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readFloatBE(offset) {
+        return this._readNumberValue(Buffer.prototype.readFloatBE, 4, offset);
+    }
+    /**
+     * Reads an FloatLE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readFloatLE(offset) {
+        return this._readNumberValue(Buffer.prototype.readFloatLE, 4, offset);
+    }
+    /**
+     * Writes a FloatBE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeFloatBE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeFloatBE, 4, value, offset);
+    }
+    /**
+     * Inserts a FloatBE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertFloatBE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeFloatBE, 4, value, offset);
+    }
+    /**
+     * Writes a FloatLE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeFloatLE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeFloatLE, 4, value, offset);
+    }
+    /**
+     * Inserts a FloatLE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertFloatLE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeFloatLE, 4, value, offset);
+    }
+    // Double Floating Point
+    /**
+     * Reads an DoublEBE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readDoubleBE(offset) {
+        return this._readNumberValue(Buffer.prototype.readDoubleBE, 8, offset);
+    }
+    /**
+     * Reads an DoubleLE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readDoubleLE(offset) {
+        return this._readNumberValue(Buffer.prototype.readDoubleLE, 8, offset);
+    }
+    /**
+     * Writes a DoubleBE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeDoubleBE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeDoubleBE, 8, value, offset);
+    }
+    /**
+     * Inserts a DoubleBE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertDoubleBE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeDoubleBE, 8, value, offset);
+    }
+    /**
+     * Writes a DoubleLE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeDoubleLE(value, offset) {
+        return this._writeNumberValue(Buffer.prototype.writeDoubleLE, 8, value, offset);
+    }
+    /**
+     * Inserts a DoubleLE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertDoubleLE(value, offset) {
+        return this._insertNumberValue(Buffer.prototype.writeDoubleLE, 8, value, offset);
+    }
+    // Strings
+    /**
+     * Reads a String from the current read position.
+     *
+     * @param arg1 { Number | String } The number of bytes to read as a String, or the BufferEncoding to use for
+     *             the string (Defaults to instance level encoding).
+     * @param encoding { String } The BufferEncoding to use for the string (Defaults to instance level encoding).
+     *
+     * @return { String }
+     */
+    readString(arg1, encoding) {
+        let lengthVal;
+        // Length provided
+        if (typeof arg1 === 'number') {
+            utils_1.checkLengthValue(arg1);
+            lengthVal = Math.min(arg1, this.length - this._readOffset);
+        }
+        else {
+            encoding = arg1;
+            lengthVal = this.length - this._readOffset;
+        }
+        // Check encoding
+        if (typeof encoding !== 'undefined') {
+            utils_1.checkEncoding(encoding);
+        }
+        const value = this._buff.slice(this._readOffset, this._readOffset + lengthVal).toString(encoding || this._encoding);
+        this._readOffset += lengthVal;
+        return value;
+    }
+    /**
+     * Inserts a String
+     *
+     * @param value { String } The String value to insert.
+     * @param offset { Number } The offset to insert the string at.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     *
+     * @return this
+     */
+    insertString(value, offset, encoding) {
+        utils_1.checkOffsetValue(offset);
+        return this._handleString(value, true, offset, encoding);
+    }
+    /**
+     * Writes a String
+     *
+     * @param value { String } The String value to write.
+     * @param arg2 { Number | String } The offset to write the string at, or the BufferEncoding to use.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     *
+     * @return this
+     */
+    writeString(value, arg2, encoding) {
+        return this._handleString(value, false, arg2, encoding);
+    }
+    /**
+     * Reads a null-terminated String from the current read position.
+     *
+     * @param encoding { String } The BufferEncoding to use for the string (Defaults to instance level encoding).
+     *
+     * @return { String }
+     */
+    readStringNT(encoding) {
+        if (typeof encoding !== 'undefined') {
+            utils_1.checkEncoding(encoding);
+        }
+        // Set null character position to the end SmartBuffer instance.
+        let nullPos = this.length;
+        // Find next null character (if one is not found, default from above is used)
+        for (let i = this._readOffset; i < this.length; i++) {
+            if (this._buff[i] === 0x00) {
+                nullPos = i;
+                break;
+            }
+        }
+        // Read string value
+        const value = this._buff.slice(this._readOffset, nullPos);
+        // Increment internal Buffer read offset
+        this._readOffset = nullPos + 1;
+        return value.toString(encoding || this._encoding);
+    }
+    /**
+     * Inserts a null-terminated String.
+     *
+     * @param value { String } The String value to write.
+     * @param arg2 { Number | String } The offset to write the string to, or the BufferEncoding to use.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     *
+     * @return this
+     */
+    insertStringNT(value, offset, encoding) {
+        utils_1.checkOffsetValue(offset);
+        // Write Values
+        this.insertString(value, offset, encoding);
+        this.insertUInt8(0x00, offset + value.length);
+        return this;
+    }
+    /**
+     * Writes a null-terminated String.
+     *
+     * @param value { String } The String value to write.
+     * @param arg2 { Number | String } The offset to write the string to, or the BufferEncoding to use.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     *
+     * @return this
+     */
+    writeStringNT(value, arg2, encoding) {
+        // Write Values
+        this.writeString(value, arg2, encoding);
+        this.writeUInt8(0x00, typeof arg2 === 'number' ? arg2 + value.length : this.writeOffset);
+        return this;
+    }
+    // Buffers
+    /**
+     * Reads a Buffer from the internal read position.
+     *
+     * @param length { Number } The length of data to read as a Buffer.
+     *
+     * @return { Buffer }
+     */
+    readBuffer(length) {
+        if (typeof length !== 'undefined') {
+            utils_1.checkLengthValue(length);
+        }
+        const lengthVal = typeof length === 'number' ? length : this.length;
+        const endPoint = Math.min(this.length, this._readOffset + lengthVal);
+        // Read buffer value
+        const value = this._buff.slice(this._readOffset, endPoint);
+        // Increment internal Buffer read offset
+        this._readOffset = endPoint;
+        return value;
+    }
+    /**
+     * Writes a Buffer to the current write position.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     *
+     * @return this
+     */
+    insertBuffer(value, offset) {
+        utils_1.checkOffsetValue(offset);
+        return this._handleBuffer(value, true, offset);
+    }
+    /**
+     * Writes a Buffer to the current write position.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     *
+     * @return this
+     */
+    writeBuffer(value, offset) {
+        return this._handleBuffer(value, false, offset);
+    }
+    /**
+     * Reads a null-terminated Buffer from the current read poisiton.
+     *
+     * @return { Buffer }
+     */
+    readBufferNT() {
+        // Set null character position to the end SmartBuffer instance.
+        let nullPos = this.length;
+        // Find next null character (if one is not found, default from above is used)
+        for (let i = this._readOffset; i < this.length; i++) {
+            if (this._buff[i] === 0x00) {
+                nullPos = i;
+                break;
+            }
+        }
+        // Read value
+        const value = this._buff.slice(this._readOffset, nullPos);
+        // Increment internal Buffer read offset
+        this._readOffset = nullPos + 1;
+        return value;
+    }
+    /**
+     * Inserts a null-terminated Buffer.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     *
+     * @return this
+     */
+    insertBufferNT(value, offset) {
+        utils_1.checkOffsetValue(offset);
+        // Write Values
+        this.insertBuffer(value, offset);
+        this.insertUInt8(0x00, offset + value.length);
+        return this;
+    }
+    /**
+     * Writes a null-terminated Buffer.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     *
+     * @return this
+     */
+    writeBufferNT(value, offset) {
+        // Checks for valid numberic value;
+        if (typeof offset !== 'undefined') {
+            utils_1.checkOffsetValue(offset);
+        }
+        // Write Values
+        this.writeBuffer(value, offset);
+        this.writeUInt8(0x00, typeof offset === 'number' ? offset + value.length : this._writeOffset);
+        return this;
+    }
+    /**
+     * Clears the SmartBuffer instance to its original empty state.
+     */
+    clear() {
+        this._writeOffset = 0;
+        this._readOffset = 0;
+        this.length = 0;
+        return this;
+    }
+    /**
+     * Gets the remaining data left to be read from the SmartBuffer instance.
+     *
+     * @return { Number }
+     */
+    remaining() {
+        return this.length - this._readOffset;
+    }
+    /**
+     * Gets the current read offset value of the SmartBuffer instance.
+     *
+     * @return { Number }
+     */
+    get readOffset() {
+        return this._readOffset;
+    }
+    /**
+     * Sets the read offset value of the SmartBuffer instance.
+     *
+     * @param offset { Number } - The offset value to set.
+     */
+    set readOffset(offset) {
+        utils_1.checkOffsetValue(offset);
+        // Check for bounds.
+        utils_1.checkTargetOffset(offset, this);
+        this._readOffset = offset;
+    }
+    /**
+     * Gets the current write offset value of the SmartBuffer instance.
+     *
+     * @return { Number }
+     */
+    get writeOffset() {
+        return this._writeOffset;
+    }
+    /**
+     * Sets the write offset value of the SmartBuffer instance.
+     *
+     * @param offset { Number } - The offset value to set.
+     */
+    set writeOffset(offset) {
+        utils_1.checkOffsetValue(offset);
+        // Check for bounds.
+        utils_1.checkTargetOffset(offset, this);
+        this._writeOffset = offset;
+    }
+    /**
+     * Gets the currently set string encoding of the SmartBuffer instance.
+     *
+     * @return { BufferEncoding } The string Buffer encoding currently set.
+     */
+    get encoding() {
+        return this._encoding;
+    }
+    /**
+     * Sets the string encoding of the SmartBuffer instance.
+     *
+     * @param encoding { BufferEncoding } The string Buffer encoding to set.
+     */
+    set encoding(encoding) {
+        utils_1.checkEncoding(encoding);
+        this._encoding = encoding;
+    }
+    /**
+     * Gets the underlying internal Buffer. (This includes unmanaged data in the Buffer)
+     *
+     * @return { Buffer } The Buffer value.
+     */
+    get internalBuffer() {
+        return this._buff;
+    }
+    /**
+     * Gets the value of the internal managed Buffer (Includes managed data only)
+     *
+     * @param { Buffer }
+     */
+    toBuffer() {
+        return this._buff.slice(0, this.length);
+    }
+    /**
+     * Gets the String value of the internal managed Buffer
+     *
+     * @param encoding { String } The BufferEncoding to display the Buffer as (defaults to instance level encoding).
+     */
+    toString(encoding) {
+        const encodingVal = typeof encoding === 'string' ? encoding : this._encoding;
+        // Check for invalid encoding.
+        utils_1.checkEncoding(encodingVal);
+        return this._buff.toString(encodingVal, 0, this.length);
+    }
+    /**
+     * Destroys the SmartBuffer instance.
+     */
+    destroy() {
+        this.clear();
+        return this;
+    }
+    /**
+     * Handles inserting and writing strings.
+     *
+     * @param value { String } The String value to insert.
+     * @param isInsert { Boolean } True if inserting a string, false if writing.
+     * @param arg2 { Number | String } The offset to insert the string at, or the BufferEncoding to use.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     */
+    _handleString(value, isInsert, arg3, encoding) {
+        let offsetVal = this._writeOffset;
+        let encodingVal = this._encoding;
+        // Check for offset
+        if (typeof arg3 === 'number') {
+            offsetVal = arg3;
+            // Check for encoding
+        }
+        else if (typeof arg3 === 'string') {
+            utils_1.checkEncoding(arg3);
+            encodingVal = arg3;
+        }
+        // Check for encoding (third param)
+        if (typeof encoding === 'string') {
+            utils_1.checkEncoding(encoding);
+            encodingVal = encoding;
+        }
+        // Calculate bytelength of string.
+        const byteLength = Buffer.byteLength(value, encodingVal);
+        // Ensure there is enough internal Buffer capacity.
+        if (isInsert) {
+            this.ensureInsertable(byteLength, offsetVal);
+        }
+        else {
+            this._ensureWriteable(byteLength, offsetVal);
+        }
+        // Write value
+        this._buff.write(value, offsetVal, byteLength, encodingVal);
+        // Increment internal Buffer write offset;
+        if (isInsert) {
+            this._writeOffset += byteLength;
+        }
+        else {
+            // If an offset was given, check to see if we wrote beyond the current writeOffset.
+            if (typeof arg3 === 'number') {
+                this._writeOffset = Math.max(this._writeOffset, offsetVal + byteLength);
+            }
+            else {
+                // If no offset was given, we wrote to the end of the SmartBuffer so increment writeOffset.
+                this._writeOffset += byteLength;
+            }
+        }
+        return this;
+    }
+    /**
+     * Handles writing or insert of a Buffer.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     */
+    _handleBuffer(value, isInsert, offset) {
+        const offsetVal = typeof offset === 'number' ? offset : this._writeOffset;
+        // Ensure there is enough internal Buffer capacity.
+        if (isInsert) {
+            this.ensureInsertable(value.length, offsetVal);
+        }
+        else {
+            this._ensureWriteable(value.length, offsetVal);
+        }
+        // Write buffer value
+        value.copy(this._buff, offsetVal);
+        // Increment internal Buffer write offset;
+        if (isInsert) {
+            this._writeOffset += value.length;
+        }
+        else {
+            // If an offset was given, check to see if we wrote beyond the current writeOffset.
+            if (typeof offset === 'number') {
+                this._writeOffset = Math.max(this._writeOffset, offsetVal + value.length);
+            }
+            else {
+                // If no offset was given, we wrote to the end of the SmartBuffer so increment writeOffset.
+                this._writeOffset += value.length;
+            }
+        }
+        return this;
+    }
+    /**
+     * Ensures that the internal Buffer is large enough to read data.
+     *
+     * @param length { Number } The length of the data that needs to be read.
+     * @param offset { Number } The offset of the data that needs to be read.
+     */
+    ensureReadable(length, offset) {
+        // Offset value defaults to managed read offset.
+        let offsetVal = this._readOffset;
+        // If an offset was provided, use it.
+        if (typeof offset !== 'undefined') {
+            // Checks for valid numberic value;
+            utils_1.checkOffsetValue(offset);
+            // Overide with custom offset.
+            offsetVal = offset;
+        }
+        // Checks if offset is below zero, or the offset+length offset is beyond the total length of the managed data.
+        if (offsetVal < 0 || offsetVal + length > this.length) {
+            throw new Error(utils_1.ERRORS.INVALID_READ_BEYOND_BOUNDS);
+        }
+    }
+    /**
+     * Ensures that the internal Buffer is large enough to insert data.
+     *
+     * @param dataLength { Number } The length of the data that needs to be written.
+     * @param offset { Number } The offset of the data to be written.
+     */
+    ensureInsertable(dataLength, offset) {
+        // Checks for valid numberic value;
+        utils_1.checkOffsetValue(offset);
+        // Ensure there is enough internal Buffer capacity.
+        this._ensureCapacity(this.length + dataLength);
+        // If an offset was provided and its not the very end of the buffer, copy data into appropriate location in regards to the offset.
+        if (offset < this.length) {
+            this._buff.copy(this._buff, offset + dataLength, offset, this._buff.length);
+        }
+        // Adjust tracked smart buffer length
+        if (offset + dataLength > this.length) {
+            this.length = offset + dataLength;
+        }
+        else {
+            this.length += dataLength;
+        }
+    }
+    /**
+     * Ensures that the internal Buffer is large enough to write data.
+     *
+     * @param dataLength { Number } The length of the data that needs to be written.
+     * @param offset { Number } The offset of the data to be written (defaults to writeOffset).
+     */
+    _ensureWriteable(dataLength, offset) {
+        const offsetVal = typeof offset === 'number' ? offset : this._writeOffset;
+        // Ensure enough capacity to write data.
+        this._ensureCapacity(offsetVal + dataLength);
+        // Adjust SmartBuffer length (if offset + length is larger than managed length, adjust length)
+        if (offsetVal + dataLength > this.length) {
+            this.length = offsetVal + dataLength;
+        }
+    }
+    /**
+     * Ensures that the internal Buffer is large enough to write at least the given amount of data.
+     *
+     * @param minLength { Number } The minimum length of the data needs to be written.
+     */
+    _ensureCapacity(minLength) {
+        const oldLength = this._buff.length;
+        if (minLength > oldLength) {
+            let data = this._buff;
+            let newLength = (oldLength * 3) / 2 + 1;
+            if (newLength < minLength) {
+                newLength = minLength;
+            }
+            this._buff = Buffer.allocUnsafe(newLength);
+            data.copy(this._buff, 0, 0, oldLength);
+        }
+    }
+    /**
+     * Reads a numeric number value using the provided function.
+     *
+     * @typeparam T { number | bigint } The type of the value to be read
+     *
+     * @param func { Function(offset: number) => number } The function to read data on the internal Buffer with.
+     * @param byteSize { Number } The number of bytes read.
+     * @param offset { Number } The offset to read from (optional). When this is not provided, the managed readOffset is used instead.
+     *
+     * @returns { T } the number value
+     */
+    _readNumberValue(func, byteSize, offset) {
+        this.ensureReadable(byteSize, offset);
+        // Call Buffer.readXXXX();
+        const value = func.call(this._buff, typeof offset === 'number' ? offset : this._readOffset);
+        // Adjust internal read offset if an optional read offset was not provided.
+        if (typeof offset === 'undefined') {
+            this._readOffset += byteSize;
+        }
+        return value;
+    }
+    /**
+     * Inserts a numeric number value based on the given offset and value.
+     *
+     * @typeparam T { number | bigint } The type of the value to be written
+     *
+     * @param func { Function(offset: T, offset?) => number} The function to write data on the internal Buffer with.
+     * @param byteSize { Number } The number of bytes written.
+     * @param value { T } The number value to write.
+     * @param offset { Number } the offset to write the number at (REQUIRED).
+     *
+     * @returns SmartBuffer this buffer
+     */
+    _insertNumberValue(func, byteSize, value, offset) {
+        // Check for invalid offset values.
+        utils_1.checkOffsetValue(offset);
+        // Ensure there is enough internal Buffer capacity. (raw offset is passed)
+        this.ensureInsertable(byteSize, offset);
+        // Call buffer.writeXXXX();
+        func.call(this._buff, value, offset);
+        // Adjusts internally managed write offset.
+        this._writeOffset += byteSize;
+        return this;
+    }
+    /**
+     * Writes a numeric number value based on the given offset and value.
+     *
+     * @typeparam T { number | bigint } The type of the value to be written
+     *
+     * @param func { Function(offset: T, offset?) => number} The function to write data on the internal Buffer with.
+     * @param byteSize { Number } The number of bytes written.
+     * @param value { T } The number value to write.
+     * @param offset { Number } the offset to write the number at (REQUIRED).
+     *
+     * @returns SmartBuffer this buffer
+     */
+    _writeNumberValue(func, byteSize, value, offset) {
+        // If an offset was provided, validate it.
+        if (typeof offset === 'number') {
+            // Check if we're writing beyond the bounds of the managed data.
+            if (offset < 0) {
+                throw new Error(utils_1.ERRORS.INVALID_WRITE_BEYOND_BOUNDS);
+            }
+            utils_1.checkOffsetValue(offset);
+        }
+        // Default to writeOffset if no offset value was given.
+        const offsetVal = typeof offset === 'number' ? offset : this._writeOffset;
+        // Ensure there is enough internal Buffer capacity. (raw offset is passed)
+        this._ensureWriteable(byteSize, offsetVal);
+        func.call(this._buff, value, offsetVal);
+        // If an offset was given, check to see if we wrote beyond the current writeOffset.
+        if (typeof offset === 'number') {
+            this._writeOffset = Math.max(this._writeOffset, offsetVal + byteSize);
+        }
+        else {
+            // If no numeric offset was given, we wrote to the end of the SmartBuffer so increment writeOffset.
+            this._writeOffset += byteSize;
+        }
+        return this;
+    }
+}
+exports.SmartBuffer = SmartBuffer;
+//# sourceMappingURL=smartbuffer.js.map
\ No newline at end of file
diff --git a/server/node_modules/smart-buffer/build/smartbuffer.js.map b/server/node_modules/smart-buffer/build/smartbuffer.js.map
new file mode 100644
index 0000000..37f0d6e
--- /dev/null
+++ b/server/node_modules/smart-buffer/build/smartbuffer.js.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/server/node_modules/smart-buffer/build/utils.js b/server/node_modules/smart-buffer/build/utils.js
new file mode 100644
index 0000000..6d55981
--- /dev/null
+++ b/server/node_modules/smart-buffer/build/utils.js
@@ -0,0 +1,108 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const buffer_1 = require("buffer");
+/**
+ * Error strings
+ */
+const ERRORS = {
+    INVALID_ENCODING: 'Invalid encoding provided. Please specify a valid encoding the internal Node.js Buffer supports.',
+    INVALID_SMARTBUFFER_SIZE: 'Invalid size provided. Size must be a valid integer greater than zero.',
+    INVALID_SMARTBUFFER_BUFFER: 'Invalid Buffer provided in SmartBufferOptions.',
+    INVALID_SMARTBUFFER_OBJECT: 'Invalid SmartBufferOptions object supplied to SmartBuffer constructor or factory methods.',
+    INVALID_OFFSET: 'An invalid offset value was provided.',
+    INVALID_OFFSET_NON_NUMBER: 'An invalid offset value was provided. A numeric value is required.',
+    INVALID_LENGTH: 'An invalid length value was provided.',
+    INVALID_LENGTH_NON_NUMBER: 'An invalid length value was provived. A numeric value is required.',
+    INVALID_TARGET_OFFSET: 'Target offset is beyond the bounds of the internal SmartBuffer data.',
+    INVALID_TARGET_LENGTH: 'Specified length value moves cursor beyong the bounds of the internal SmartBuffer data.',
+    INVALID_READ_BEYOND_BOUNDS: 'Attempted to read beyond the bounds of the managed data.',
+    INVALID_WRITE_BEYOND_BOUNDS: 'Attempted to write beyond the bounds of the managed data.'
+};
+exports.ERRORS = ERRORS;
+/**
+ * Checks if a given encoding is a valid Buffer encoding. (Throws an exception if check fails)
+ *
+ * @param { String } encoding The encoding string to check.
+ */
+function checkEncoding(encoding) {
+    if (!buffer_1.Buffer.isEncoding(encoding)) {
+        throw new Error(ERRORS.INVALID_ENCODING);
+    }
+}
+exports.checkEncoding = checkEncoding;
+/**
+ * Checks if a given number is a finite integer. (Throws an exception if check fails)
+ *
+ * @param { Number } value The number value to check.
+ */
+function isFiniteInteger(value) {
+    return typeof value === 'number' && isFinite(value) && isInteger(value);
+}
+exports.isFiniteInteger = isFiniteInteger;
+/**
+ * Checks if an offset/length value is valid. (Throws an exception if check fails)
+ *
+ * @param value The value to check.
+ * @param offset True if checking an offset, false if checking a length.
+ */
+function checkOffsetOrLengthValue(value, offset) {
+    if (typeof value === 'number') {
+        // Check for non finite/non integers
+        if (!isFiniteInteger(value) || value < 0) {
+            throw new Error(offset ? ERRORS.INVALID_OFFSET : ERRORS.INVALID_LENGTH);
+        }
+    }
+    else {
+        throw new Error(offset ? ERRORS.INVALID_OFFSET_NON_NUMBER : ERRORS.INVALID_LENGTH_NON_NUMBER);
+    }
+}
+/**
+ * Checks if a length value is valid. (Throws an exception if check fails)
+ *
+ * @param { Number } length The value to check.
+ */
+function checkLengthValue(length) {
+    checkOffsetOrLengthValue(length, false);
+}
+exports.checkLengthValue = checkLengthValue;
+/**
+ * Checks if a offset value is valid. (Throws an exception if check fails)
+ *
+ * @param { Number } offset The value to check.
+ */
+function checkOffsetValue(offset) {
+    checkOffsetOrLengthValue(offset, true);
+}
+exports.checkOffsetValue = checkOffsetValue;
+/**
+ * Checks if a target offset value is out of bounds. (Throws an exception if check fails)
+ *
+ * @param { Number } offset The offset value to check.
+ * @param { SmartBuffer } buff The SmartBuffer instance to check against.
+ */
+function checkTargetOffset(offset, buff) {
+    if (offset < 0 || offset > buff.length) {
+        throw new Error(ERRORS.INVALID_TARGET_OFFSET);
+    }
+}
+exports.checkTargetOffset = checkTargetOffset;
+/**
+ * Determines whether a given number is a integer.
+ * @param value The number to check.
+ */
+function isInteger(value) {
+    return typeof value === 'number' && isFinite(value) && Math.floor(value) === value;
+}
+/**
+ * Throws if Node.js version is too low to support bigint
+ */
+function bigIntAndBufferInt64Check(bufferMethod) {
+    if (typeof BigInt === 'undefined') {
+        throw new Error('Platform does not support JS BigInt type.');
+    }
+    if (typeof buffer_1.Buffer.prototype[bufferMethod] === 'undefined') {
+        throw new Error(`Platform does not support Buffer.prototype.${bufferMethod}.`);
+    }
+}
+exports.bigIntAndBufferInt64Check = bigIntAndBufferInt64Check;
+//# sourceMappingURL=utils.js.map
\ No newline at end of file
diff --git a/server/node_modules/smart-buffer/build/utils.js.map b/server/node_modules/smart-buffer/build/utils.js.map
new file mode 100644
index 0000000..fc7388d
--- /dev/null
+++ b/server/node_modules/smart-buffer/build/utils.js.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/server/node_modules/smart-buffer/docs/CHANGELOG.md b/server/node_modules/smart-buffer/docs/CHANGELOG.md
new file mode 100644
index 0000000..1199a4d
--- /dev/null
+++ b/server/node_modules/smart-buffer/docs/CHANGELOG.md
@@ -0,0 +1,70 @@
+# Change Log
+## 4.1.0
+> Released 07/24/2019
+* Adds int64 support for node v12+
+* Drops support for node v4
+
+## 4.0
+> Released 10/21/2017
+* Major breaking changes arriving in v4.
+
+### New Features
+* Ability to read data from a specific offset. ex: readInt8(5)
+* Ability to write over data when an offset is given (see breaking changes) ex:  writeInt8(5, 0);
+* Ability to set internal read and write offsets.
+
+
+
+### Breaking Changes
+
+* Old constructor patterns have been completely removed. It's now required to use the SmartBuffer.fromXXX() factory constructors. Read more on the v4 docs.
+* rewind(), skip(), moveTo() have been removed.
+* Internal private properties are now prefixed with underscores (_).
+* **All** writeXXX() methods that are given an offset will now **overwrite data** instead of insert
+* insertXXX() methods have been added for when you want to insert data at a specific offset (this replaces the old behavior of writeXXX() when an offset was provided)
+
+
+### Other Changes
+* Standardizd error messaging
+* Standardized offset/length bounds and sanity checking
+* General overall cleanup of code.
+
+## 3.0.3
+> Released 02/19/2017
+* Adds missing type definitions for some internal functions.
+
+## 3.0.2
+> Released 02/17/2017
+
+### Bug Fixes
+* Fixes a bug where using readString with a length of zero resulted in reading the remaining data instead of returning an empty string. (Fixed by Seldszar)
+
+## 3.0.1
+> Released 02/15/2017
+
+### Bug Fixes
+* Fixes a bug leftover from the TypeScript refactor where .readIntXXX() resulted in .readUIntXXX() being called by mistake.
+
+## 3.0
+> Released 02/12/2017
+
+### Bug Fixes
+* readUIntXXXX() methods will now throw an exception if they attempt to read beyond the bounds of the valid buffer data available.
+    * **Note** This is technically a breaking change, so version is bumped to 3.x.
+
+## 2.0
+> Relased 01/30/2017
+
+### New Features:
+
+* Entire package re-written in TypeScript (2.1)
+* Backwards compatibility is preserved for now
+* New factory methods for creating SmartBuffer instances
+    * SmartBuffer.fromSize()
+    * SmartBuffer.fromBuffer()
+    * SmartBuffer.fromOptions()
+* New SmartBufferOptions constructor options
+* Added additional tests
+
+### Bug Fixes:
+* Fixes a bug where reading null terminated strings may result in an exception.
diff --git a/server/node_modules/smart-buffer/docs/README_v3.md b/server/node_modules/smart-buffer/docs/README_v3.md
new file mode 100644
index 0000000..b7c48b8
--- /dev/null
+++ b/server/node_modules/smart-buffer/docs/README_v3.md
@@ -0,0 +1,367 @@
+smart-buffer  [![Build Status](https://travis-ci.org/JoshGlazebrook/smart-buffer.svg?branch=master)](https://travis-ci.org/JoshGlazebrook/smart-buffer)  [![Coverage Status](https://coveralls.io/repos/github/JoshGlazebrook/smart-buffer/badge.svg?branch=master)](https://coveralls.io/github/JoshGlazebrook/smart-buffer?branch=master)
+=============
+
+smart-buffer is a light Buffer wrapper that takes away the need to keep track of what position to read and write data to and from the underlying Buffer. It also adds null terminating string operations and **grows** as you add more data.
+
+![stats](https://nodei.co/npm/smart-buffer.png?downloads=true&downloadRank=true&stars=true "stats")
+
+### What it's useful for:
+
+I created smart-buffer because I wanted to simplify the process of using Buffer for building and reading network packets to send over a socket. Rather than having to keep track of which position I need to write a UInt16 to after adding a string of variable length, I simply don't have to.
+
+Key Features:
+* Proxies all of the Buffer write and read functions.
+* Keeps track of read and write positions for you.
+* Grows the internal Buffer as you add data to it. 
+* Useful string operations. (Null terminating strings)
+* Allows for inserting values at specific points in the internal Buffer.
+* Built in TypeScript
+* Type Definitions Provided
+
+Requirements:
+* Node v4.0+ is supported at this time.  (Versions prior to 2.0 will work on node 0.10)
+
+
+#### Note:
+smart-buffer can be used for writing to an underlying buffer as well as reading from it. It however does not function correctly if you're mixing both read and write operations with each other.
+
+## Breaking Changes with 2.0
+The latest version (2.0+) is written in TypeScript, and are compiled to ES6 Javascript. This means the earliest Node.js it supports will be 4.x (in strict mode.) If you're using version 6 and above it will work without any issues. From an API standpoint, 2.0 is backwards compatible. The only difference is SmartBuffer is not exported directly as the root module.
+
+## Breaking Changes with 3.0
+Starting with 3.0, if any of the readIntXXXX() methods are called and the requested data is larger than the bounds of the internally managed valid buffer data, an exception will now be thrown.
+
+## Installing:
+
+`npm install smart-buffer`
+
+or
+
+`yarn add smart-buffer`
+
+Note: The published NPM package includes the built javascript library. 
+If you cloned this repo and wish to build the library manually use:
+
+`tsc -p ./`
+
+## Using smart-buffer
+
+### Example
+
+Say you were building a packet that had to conform to the following protocol:
+
+`[PacketType:2][PacketLength:2][Data:XX]`
+
+To build this packet using the vanilla Buffer class, you would have to count up the length of the data payload beforehand. You would also need to keep track of the current "cursor" position in your Buffer so you write everything in the right places. With smart-buffer you don't have to do either of those things.
+
+```javascript
+// 1.x (javascript)
+var SmartBuffer = require('smart-buffer');
+
+// 1.x (typescript)
+import SmartBuffer = require('smart-buffer');
+
+// 2.x+ (javascript)
+const SmartBuffer = require('smart-buffer').SmartBuffer;
+
+// 2.x+ (typescript)
+import { SmartBuffer, SmartBufferOptions} from 'smart-buffer';
+
+function createLoginPacket(username, password, age, country) {
+    let packet = new SmartBuffer();
+    packet.writeUInt16LE(0x0060); // Login Packet Type/ID
+    packet.writeStringNT(username);
+    packet.writeStringNT(password);
+    packet.writeUInt8(age);
+    packet.writeStringNT(country);
+    packet.writeUInt16LE(packet.length - 2, 2);
+    
+    return packet.toBuffer();
+}
+```
+With the above function, you now can do this:
+```javascript
+let login = createLoginPacket("Josh", "secret123", 22, "United States");
+
+// <Buffer 60 00 1e 00 4a 6f 73 68 00 73 65 63 72 65 74 31 32 33 00 16 55 6e 69 74 65 64 20 53 74 61 74 65 73 00>
+```
+Notice that the `[PacketLength:2]` part of the packet was inserted after we had added everything else, and as shown in the Buffer dump above, is in the correct location along with everything else.
+
+Reading back the packet we created above is just as easy:
+```javascript
+
+let reader = SmartBuffer.fromBuffer(login);
+
+let logininfo = {
+    packetType: reader.readUInt16LE(),
+    packetLength: reader.readUInt16LE(),
+    username: reader.readStringNT(),
+    password: reader.readStringNT(),
+    age: reader.readUInt8(),
+    country: reader.readStringNT()
+};
+
+/*
+{ 
+    packetType: 96, (0x0060)
+    packetLength: 30,
+    username: 'Josh',
+    password: 'secret123',
+    age: 22,
+    country: 'United States' 
+};
+*/
+```
+
+# Api Reference:
+
+### Constructing a smart-buffer
+
+smart-buffer has a few different ways to construct an instance. Starting with version 2.0, the following factory methods are preffered.
+
+```javascript
+let SmartBuffer = require('smart-buffer');
+
+// Creating SmartBuffer from existing Buffer
+let buff = SmartBuffer.fromBuffer(buffer); // Creates instance from buffer. (Uses default utf8 encoding)
+let buff = SmartBuffer.fromBuffer(buffer, 'ascii'); // Creates instance from buffer with ascii encoding for Strings. 
+
+// Creating SmartBuffer with specified internal Buffer size.
+let buff = SmartBuffer.fromSize(1024); // Creates instance with internal Buffer size of 1024.
+let buff = SmartBuffer.fromSize(1024, 'utf8'); // Creates instance with intenral Buffer size of 1024, and utf8 encoding. 
+
+// Creating SmartBuffer with options object. This one specifies size and encoding.
+let buff = SmartBuffer.fromOptions({
+    size: 1024,
+    encoding: 'ascii'
+});
+
+// Creating SmartBuffer with options object. This one specified an existing Buffer.
+let buff = SmartBuffer.fromOptions({
+    buff: buffer
+});
+
+// Just want a regular SmartBuffer with all default options?
+let buff = new SmartBuffer();
+```
+
+## Backwards Compatibility:
+
+All constructors used prior to 2.0 still are supported. However it's not recommended to use these.
+
+```javascript
+let writer = new SmartBuffer();               // Defaults to utf8, 4096 length internal Buffer.
+let writer = new SmartBuffer(1024);           // Defaults to utf8, 1024 length internal Buffer.
+let writer = new SmartBuffer('ascii');         // Sets to ascii encoding, 4096 length internal buffer.
+let writer = new SmartBuffer(1024, 'ascii');  // Sets to ascii encoding, 1024 length internal buffer.
+```
+
+## Reading Data
+
+smart-buffer supports all of the common read functions you will find in the vanilla Buffer class. The only difference is, you do not need to specify which location to start reading from. This is possible because as you read data out of a smart-buffer, it automatically progresses an internal read offset/position to know where to pick up from on the next read.
+
+## Reading Numeric Values
+
+When numeric values, you simply need to call the function you want, and the data is returned.
+
+Supported Operations:
+* readInt8
+* readInt16BE
+* readInt16LE
+* readInt32BE
+* readInt32LE
+* readBigInt64LE
+* readBigInt64BE
+* readUInt8
+* readUInt16BE
+* readUInt16LE
+* readUInt32BE
+* readUInt32LE
+* readBigUInt64LE
+* readBigUInt64BE
+* readFloatBE
+* readFloatLE
+* readDoubleBE
+* readDoubleLE
+
+```javascript
+let reader = new SmartBuffer(somebuffer);
+let num = reader.readInt8();
+```
+
+## Reading String Values
+
+When reading String values, you can either choose to read a null terminated string, or a string of a specified length.
+
+### SmartBuffer.readStringNT( [encoding] )
+> `String` **String encoding to use**  - Defaults to the encoding set in the constructor. 
+
+returns `String`
+
+> Note: When readStringNT is called and there is no null character found, smart-buffer will read to the end of the internal Buffer.
+
+### SmartBuffer.readString( [length] )
+### SmartBuffer.readString( [encoding] )
+### SmartBuffer.readString( [length], [encoding] )
+> `Number` **Length of the string to read**
+
+> `String` **String encoding to use** - Defaults to the encoding set in the constructor, or utf8.
+
+returns `String`
+
+> Note: When readString is called without a specified length, smart-buffer will read to the end of the internal Buffer.
+
+
+
+## Reading Buffer Values
+
+### SmartBuffer.readBuffer( length )
+> `Number` **Length of data to read into a Buffer**
+
+returns `Buffer`
+
+> Note: This function uses `slice` to retrieve the Buffer.
+
+
+### SmartBuffer.readBufferNT()
+
+returns `Buffer`
+
+> Note: This reads the next sequence of bytes in the buffer until a null (0x00) value is found. (Null terminated buffer)
+> Note: This function uses `slice` to retrieve the Buffer.
+
+
+## Writing Data
+
+smart-buffer supports all of the common write functions you will find in the vanilla Buffer class. The only difference is, you do not need to specify which location to write to in your Buffer by default. You do however have the option of **inserting** a piece of data into your smart-buffer at a given location. 
+
+
+## Writing Numeric Values
+
+
+For numeric values, you simply need to call the function you want, and the data is written at the end of the internal Buffer's current write position. You can specify a offset/position to **insert** the given value at, but keep in mind this does not override data at the given position. This feature also does not work properly when inserting a value beyond the current internal length of the smart-buffer (length being the .length property of the smart-buffer instance you're writing to)
+
+Supported Operations:
+* writeInt8
+* writeInt16BE
+* writeInt16LE
+* writeInt32BE
+* writeInt32LE
+* writeBigInt64BE
+* writeBigInt64LE
+* writeUInt8
+* writeUInt16BE
+* writeUInt16LE
+* writeUInt32BE
+* writeUInt32LE
+* writeBigUInt64BE
+* writeBigUInt64LE
+* writeFloatBE
+* writeFloatLE
+* writeDoubleBE
+* writeDoubleLE
+
+The following signature is the same for all the above functions:
+
+### SmartBuffer.writeInt8( value, [offset] )
+> `Number` **A valid Int8 number**
+
+> `Number` **The position to insert this value at** 
+
+returns this 
+
+> Note: All write operations return `this` to allow for chaining.
+
+## Writing String Values
+
+When reading String values, you can either choose to write a null terminated string, or a non null terminated string.
+
+### SmartBuffer.writeStringNT( value, [offset], [encoding] )
+### SmartBuffer.writeStringNT( value, [offset] )
+### SmartBuffer.writeStringNT( value, [encoding] )
+> `String` **String value to write**
+
+> `Number` **The position to insert this String at**
+
+> `String` **The String encoding to use.** - Defaults to the encoding set in the constructor, or utf8.
+
+returns this
+
+### SmartBuffer.writeString( value, [offset], [encoding] )
+### SmartBuffer.writeString( value, [offset] )
+### SmartBuffer.writeString( value, [encoding] )
+> `String` **String value to write**
+
+> `Number` **The position to insert this String at**
+
+> `String` **The String encoding to use** - Defaults to the encoding set in the constructor, or utf8.
+
+returns this
+
+
+## Writing Buffer Values
+
+### SmartBuffer.writeBuffer( value, [offset] )
+> `Buffer` **Buffer value to write**
+
+> `Number` **The position to insert this Buffer's content at**
+
+returns this
+
+### SmartBuffer.writeBufferNT( value, [offset] )
+> `Buffer` **Buffer value to write**
+
+> `Number` **The position to insert this Buffer's content at**
+
+returns this
+
+
+## Utility Functions
+
+### SmartBuffer.clear()
+Resets the SmartBuffer to its default state where it can be reused for reading or writing.
+
+### SmartBuffer.remaining()
+
+returns `Number` The amount of data left to read based on the current read Position.
+
+### SmartBuffer.skip( value )
+> `Number` **The amount of bytes to skip ahead**
+
+Skips the read position ahead by the given value.
+
+returns this
+
+### SmartBuffer.rewind( value )
+> `Number` **The amount of bytes to reward backwards**
+
+Rewinds the read position backwards by the given value.
+
+returns this
+
+### SmartBuffer.moveTo( position )
+> `Number` **The point to skip the read position to**
+
+Moves the read position to the given point.
+returns this
+
+### SmartBuffer.toBuffer()
+
+returns `Buffer` A Buffer containing the contents of the internal Buffer.
+
+> Note: This uses the slice function.
+
+### SmartBuffer.toString( [encoding] )
+> `String` **The String encoding to use** - Defaults to the encoding set in the constructor, or utf8.
+
+returns `String` The internal Buffer in String representation.
+
+## Properties
+
+### SmartBuffer.length
+
+returns `Number` **The length of the data that is being tracked in the internal Buffer** - Does NOT return the absolute length of the internal Buffer being written to.
+
+## License
+
+This work is licensed under the [MIT license](http://en.wikipedia.org/wiki/MIT_License).
\ No newline at end of file
diff --git a/server/node_modules/smart-buffer/docs/ROADMAP.md b/server/node_modules/smart-buffer/docs/ROADMAP.md
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/smart-buffer/package.json b/server/node_modules/smart-buffer/package.json
new file mode 100644
index 0000000..2f326f2
--- /dev/null
+++ b/server/node_modules/smart-buffer/package.json
@@ -0,0 +1,79 @@
+{
+  "name": "smart-buffer",
+  "version": "4.2.0",
+  "description": "smart-buffer is a Buffer wrapper that adds automatic read & write offset tracking, string operations, data insertions, and more.",
+  "main": "build/smartbuffer.js",
+  "contributors": ["syvita"],
+  "homepage": "https://github.com/JoshGlazebrook/smart-buffer/",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/JoshGlazebrook/smart-buffer.git"
+  },
+  "bugs": {
+    "url": "https://github.com/JoshGlazebrook/smart-buffer/issues"
+  },
+  "keywords": [
+    "buffer",
+    "smart",
+    "packet",
+    "serialize",
+    "network",
+    "cursor",
+    "simple"
+  ],
+  "engines": {
+    "node": ">= 6.0.0",
+    "npm": ">= 3.0.0"
+  },
+  "author": "Josh Glazebrook",
+  "license": "MIT",
+  "readmeFilename": "README.md",
+  "devDependencies": {
+    "@types/chai": "4.1.7",
+    "@types/mocha": "5.2.7",
+    "@types/node": "^12.0.0",
+    "chai": "4.2.0",
+    "coveralls": "3.0.5",
+    "istanbul": "^0.4.5",
+    "mocha": "6.2.0",
+    "mocha-lcov-reporter": "^1.3.0",
+    "nyc": "14.1.1",
+    "source-map-support": "0.5.12",
+    "ts-node": "8.3.0",
+    "tslint": "5.18.0",
+    "typescript": "^3.2.1"
+  },
+  "typings": "typings/smartbuffer.d.ts",
+  "dependencies": {},
+  "scripts": {
+    "prepublish": "npm install -g typescript && npm run build",
+    "test": "NODE_ENV=test mocha --recursive --require ts-node/register test/**/*.ts",
+    "coverage": "NODE_ENV=test nyc npm test",
+    "coveralls": "NODE_ENV=test nyc npm test && nyc report --reporter=text-lcov | coveralls",
+    "lint": "tslint --type-check --project tsconfig.json 'src/**/*.ts'",
+    "build": "tsc -p ./"
+  },
+  "nyc": {
+    "extension": [
+      ".ts",
+      ".tsx"
+    ],
+    "include": [
+      "src/*.ts",
+      "src/**/*.ts"
+    ],
+    "exclude": [
+      "**.*.d.ts",
+      "node_modules",
+      "typings"
+    ],
+    "require": [
+      "ts-node/register"
+    ],
+    "reporter": [
+      "json",
+      "html"
+    ],
+    "all": true
+  }
+}
diff --git a/server/node_modules/smart-buffer/typings/smartbuffer.d.ts b/server/node_modules/smart-buffer/typings/smartbuffer.d.ts
new file mode 100644
index 0000000..d07379b
--- /dev/null
+++ b/server/node_modules/smart-buffer/typings/smartbuffer.d.ts
@@ -0,0 +1,755 @@
+/// <reference types="node" />
+/**
+ * Object interface for constructing new SmartBuffer instances.
+ */
+interface SmartBufferOptions {
+    encoding?: BufferEncoding;
+    size?: number;
+    buff?: Buffer;
+}
+declare class SmartBuffer {
+    length: number;
+    private _encoding;
+    private _buff;
+    private _writeOffset;
+    private _readOffset;
+    /**
+     * Creates a new SmartBuffer instance.
+     *
+     * @param options { SmartBufferOptions } The SmartBufferOptions to apply to this instance.
+     */
+    constructor(options?: SmartBufferOptions);
+    /**
+     * Creates a new SmartBuffer instance with the provided internal Buffer size and optional encoding.
+     *
+     * @param size { Number } The size of the internal Buffer.
+     * @param encoding { String } The BufferEncoding to use for strings.
+     *
+     * @return { SmartBuffer }
+     */
+    static fromSize(size: number, encoding?: BufferEncoding): SmartBuffer;
+    /**
+     * Creates a new SmartBuffer instance with the provided Buffer and optional encoding.
+     *
+     * @param buffer { Buffer } The Buffer to use as the internal Buffer value.
+     * @param encoding { String } The BufferEncoding to use for strings.
+     *
+     * @return { SmartBuffer }
+     */
+    static fromBuffer(buff: Buffer, encoding?: BufferEncoding): SmartBuffer;
+    /**
+     * Creates a new SmartBuffer instance with the provided SmartBufferOptions options.
+     *
+     * @param options { SmartBufferOptions } The options to use when creating the SmartBuffer instance.
+     */
+    static fromOptions(options: SmartBufferOptions): SmartBuffer;
+    /**
+     * Type checking function that determines if an object is a SmartBufferOptions object.
+     */
+    static isSmartBufferOptions(options: SmartBufferOptions): options is SmartBufferOptions;
+    /**
+     * Reads an Int8 value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt8(offset?: number): number;
+    /**
+     * Reads an Int16BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt16BE(offset?: number): number;
+    /**
+     * Reads an Int16LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt16LE(offset?: number): number;
+    /**
+     * Reads an Int32BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt32BE(offset?: number): number;
+    /**
+     * Reads an Int32LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readInt32LE(offset?: number): number;
+    /**
+     * Reads a BigInt64BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { BigInt }
+     */
+    readBigInt64BE(offset?: number): bigint;
+    /**
+     * Reads a BigInt64LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { BigInt }
+     */
+    readBigInt64LE(offset?: number): bigint;
+    /**
+     * Writes an Int8 value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt8(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an Int8 value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt8(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes an Int16BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt16BE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an Int16BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt16BE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes an Int16LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt16LE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an Int16LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt16LE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes an Int32BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt32BE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an Int32BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt32BE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes an Int32LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeInt32LE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an Int32LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertInt32LE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes a BigInt64BE value to the current write position (or at optional offset).
+     *
+     * @param value { BigInt } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeBigInt64BE(value: bigint, offset?: number): SmartBuffer;
+    /**
+     * Inserts a BigInt64BE value at the given offset value.
+     *
+     * @param value { BigInt } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertBigInt64BE(value: bigint, offset: number): SmartBuffer;
+    /**
+     * Writes a BigInt64LE value to the current write position (or at optional offset).
+     *
+     * @param value { BigInt } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeBigInt64LE(value: bigint, offset?: number): SmartBuffer;
+    /**
+     * Inserts a Int64LE value at the given offset value.
+     *
+     * @param value { BigInt } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertBigInt64LE(value: bigint, offset: number): SmartBuffer;
+    /**
+     * Reads an UInt8 value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt8(offset?: number): number;
+    /**
+     * Reads an UInt16BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt16BE(offset?: number): number;
+    /**
+     * Reads an UInt16LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt16LE(offset?: number): number;
+    /**
+     * Reads an UInt32BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt32BE(offset?: number): number;
+    /**
+     * Reads an UInt32LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readUInt32LE(offset?: number): number;
+    /**
+     * Reads a BigUInt64BE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { BigInt }
+     */
+    readBigUInt64BE(offset?: number): bigint;
+    /**
+     * Reads a BigUInt64LE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { BigInt }
+     */
+    readBigUInt64LE(offset?: number): bigint;
+    /**
+     * Writes an UInt8 value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt8(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an UInt8 value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt8(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes an UInt16BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt16BE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an UInt16BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt16BE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes an UInt16LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt16LE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an UInt16LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt16LE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes an UInt32BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt32BE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an UInt32BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt32BE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes an UInt32LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeUInt32LE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts an UInt32LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertUInt32LE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes a BigUInt64BE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeBigUInt64BE(value: bigint, offset?: number): SmartBuffer;
+    /**
+     * Inserts a BigUInt64BE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertBigUInt64BE(value: bigint, offset: number): SmartBuffer;
+    /**
+     * Writes a BigUInt64LE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeBigUInt64LE(value: bigint, offset?: number): SmartBuffer;
+    /**
+     * Inserts a BigUInt64LE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertBigUInt64LE(value: bigint, offset: number): SmartBuffer;
+    /**
+     * Reads an FloatBE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readFloatBE(offset?: number): number;
+    /**
+     * Reads an FloatLE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readFloatLE(offset?: number): number;
+    /**
+     * Writes a FloatBE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeFloatBE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts a FloatBE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertFloatBE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes a FloatLE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeFloatLE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts a FloatLE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertFloatLE(value: number, offset: number): SmartBuffer;
+    /**
+     * Reads an DoublEBE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readDoubleBE(offset?: number): number;
+    /**
+     * Reads an DoubleLE value from the current read position or an optionally provided offset.
+     *
+     * @param offset { Number } The offset to read data from (optional)
+     * @return { Number }
+     */
+    readDoubleLE(offset?: number): number;
+    /**
+     * Writes a DoubleBE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeDoubleBE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts a DoubleBE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertDoubleBE(value: number, offset: number): SmartBuffer;
+    /**
+     * Writes a DoubleLE value to the current write position (or at optional offset).
+     *
+     * @param value { Number } The value to write.
+     * @param offset { Number } The offset to write the value at.
+     *
+     * @return this
+     */
+    writeDoubleLE(value: number, offset?: number): SmartBuffer;
+    /**
+     * Inserts a DoubleLE value at the given offset value.
+     *
+     * @param value { Number } The value to insert.
+     * @param offset { Number } The offset to insert the value at.
+     *
+     * @return this
+     */
+    insertDoubleLE(value: number, offset: number): SmartBuffer;
+    /**
+     * Reads a String from the current read position.
+     *
+     * @param arg1 { Number | String } The number of bytes to read as a String, or the BufferEncoding to use for
+     *             the string (Defaults to instance level encoding).
+     * @param encoding { String } The BufferEncoding to use for the string (Defaults to instance level encoding).
+     *
+     * @return { String }
+     */
+    readString(arg1?: number | BufferEncoding, encoding?: BufferEncoding): string;
+    /**
+     * Inserts a String
+     *
+     * @param value { String } The String value to insert.
+     * @param offset { Number } The offset to insert the string at.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     *
+     * @return this
+     */
+    insertString(value: string, offset: number, encoding?: BufferEncoding): SmartBuffer;
+    /**
+     * Writes a String
+     *
+     * @param value { String } The String value to write.
+     * @param arg2 { Number | String } The offset to write the string at, or the BufferEncoding to use.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     *
+     * @return this
+     */
+    writeString(value: string, arg2?: number | BufferEncoding, encoding?: BufferEncoding): SmartBuffer;
+    /**
+     * Reads a null-terminated String from the current read position.
+     *
+     * @param encoding { String } The BufferEncoding to use for the string (Defaults to instance level encoding).
+     *
+     * @return { String }
+     */
+    readStringNT(encoding?: BufferEncoding): string;
+    /**
+     * Inserts a null-terminated String.
+     *
+     * @param value { String } The String value to write.
+     * @param arg2 { Number | String } The offset to write the string to, or the BufferEncoding to use.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     *
+     * @return this
+     */
+    insertStringNT(value: string, offset: number, encoding?: BufferEncoding): SmartBuffer;
+    /**
+     * Writes a null-terminated String.
+     *
+     * @param value { String } The String value to write.
+     * @param arg2 { Number | String } The offset to write the string to, or the BufferEncoding to use.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     *
+     * @return this
+     */
+    writeStringNT(value: string, arg2?: number | BufferEncoding, encoding?: BufferEncoding): SmartBuffer;
+    /**
+     * Reads a Buffer from the internal read position.
+     *
+     * @param length { Number } The length of data to read as a Buffer.
+     *
+     * @return { Buffer }
+     */
+    readBuffer(length?: number): Buffer;
+    /**
+     * Writes a Buffer to the current write position.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     *
+     * @return this
+     */
+    insertBuffer(value: Buffer, offset: number): SmartBuffer;
+    /**
+     * Writes a Buffer to the current write position.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     *
+     * @return this
+     */
+    writeBuffer(value: Buffer, offset?: number): SmartBuffer;
+    /**
+     * Reads a null-terminated Buffer from the current read poisiton.
+     *
+     * @return { Buffer }
+     */
+    readBufferNT(): Buffer;
+    /**
+     * Inserts a null-terminated Buffer.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     *
+     * @return this
+     */
+    insertBufferNT(value: Buffer, offset: number): SmartBuffer;
+    /**
+     * Writes a null-terminated Buffer.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     *
+     * @return this
+     */
+    writeBufferNT(value: Buffer, offset?: number): SmartBuffer;
+    /**
+     * Clears the SmartBuffer instance to its original empty state.
+     */
+    clear(): SmartBuffer;
+    /**
+     * Gets the remaining data left to be read from the SmartBuffer instance.
+     *
+     * @return { Number }
+     */
+    remaining(): number;
+    /**
+     * Gets the current read offset value of the SmartBuffer instance.
+     *
+     * @return { Number }
+     */
+    /**
+    * Sets the read offset value of the SmartBuffer instance.
+    *
+    * @param offset { Number } - The offset value to set.
+    */
+    readOffset: number;
+    /**
+     * Gets the current write offset value of the SmartBuffer instance.
+     *
+     * @return { Number }
+     */
+    /**
+    * Sets the write offset value of the SmartBuffer instance.
+    *
+    * @param offset { Number } - The offset value to set.
+    */
+    writeOffset: number;
+    /**
+     * Gets the currently set string encoding of the SmartBuffer instance.
+     *
+     * @return { BufferEncoding } The string Buffer encoding currently set.
+     */
+    /**
+    * Sets the string encoding of the SmartBuffer instance.
+    *
+    * @param encoding { BufferEncoding } The string Buffer encoding to set.
+    */
+    encoding: BufferEncoding;
+    /**
+     * Gets the underlying internal Buffer. (This includes unmanaged data in the Buffer)
+     *
+     * @return { Buffer } The Buffer value.
+     */
+    readonly internalBuffer: Buffer;
+    /**
+     * Gets the value of the internal managed Buffer (Includes managed data only)
+     *
+     * @param { Buffer }
+     */
+    toBuffer(): Buffer;
+    /**
+     * Gets the String value of the internal managed Buffer
+     *
+     * @param encoding { String } The BufferEncoding to display the Buffer as (defaults to instance level encoding).
+     */
+    toString(encoding?: BufferEncoding): string;
+    /**
+     * Destroys the SmartBuffer instance.
+     */
+    destroy(): SmartBuffer;
+    /**
+     * Handles inserting and writing strings.
+     *
+     * @param value { String } The String value to insert.
+     * @param isInsert { Boolean } True if inserting a string, false if writing.
+     * @param arg2 { Number | String } The offset to insert the string at, or the BufferEncoding to use.
+     * @param encoding { String } The BufferEncoding to use for writing strings (defaults to instance encoding).
+     */
+    private _handleString;
+    /**
+     * Handles writing or insert of a Buffer.
+     *
+     * @param value { Buffer } The Buffer to write.
+     * @param offset { Number } The offset to write the Buffer to.
+     */
+    private _handleBuffer;
+    /**
+     * Ensures that the internal Buffer is large enough to read data.
+     *
+     * @param length { Number } The length of the data that needs to be read.
+     * @param offset { Number } The offset of the data that needs to be read.
+     */
+    private ensureReadable;
+    /**
+     * Ensures that the internal Buffer is large enough to insert data.
+     *
+     * @param dataLength { Number } The length of the data that needs to be written.
+     * @param offset { Number } The offset of the data to be written.
+     */
+    private ensureInsertable;
+    /**
+     * Ensures that the internal Buffer is large enough to write data.
+     *
+     * @param dataLength { Number } The length of the data that needs to be written.
+     * @param offset { Number } The offset of the data to be written (defaults to writeOffset).
+     */
+    private _ensureWriteable;
+    /**
+     * Ensures that the internal Buffer is large enough to write at least the given amount of data.
+     *
+     * @param minLength { Number } The minimum length of the data needs to be written.
+     */
+    private _ensureCapacity;
+    /**
+     * Reads a numeric number value using the provided function.
+     *
+     * @typeparam T { number | bigint } The type of the value to be read
+     *
+     * @param func { Function(offset: number) => number } The function to read data on the internal Buffer with.
+     * @param byteSize { Number } The number of bytes read.
+     * @param offset { Number } The offset to read from (optional). When this is not provided, the managed readOffset is used instead.
+     *
+     * @returns { T } the number value
+     */
+    private _readNumberValue;
+    /**
+     * Inserts a numeric number value based on the given offset and value.
+     *
+     * @typeparam T { number | bigint } The type of the value to be written
+     *
+     * @param func { Function(offset: T, offset?) => number} The function to write data on the internal Buffer with.
+     * @param byteSize { Number } The number of bytes written.
+     * @param value { T } The number value to write.
+     * @param offset { Number } the offset to write the number at (REQUIRED).
+     *
+     * @returns SmartBuffer this buffer
+     */
+    private _insertNumberValue;
+    /**
+     * Writes a numeric number value based on the given offset and value.
+     *
+     * @typeparam T { number | bigint } The type of the value to be written
+     *
+     * @param func { Function(offset: T, offset?) => number} The function to write data on the internal Buffer with.
+     * @param byteSize { Number } The number of bytes written.
+     * @param value { T } The number value to write.
+     * @param offset { Number } the offset to write the number at (REQUIRED).
+     *
+     * @returns SmartBuffer this buffer
+     */
+    private _writeNumberValue;
+}
+export { SmartBufferOptions, SmartBuffer };
diff --git a/server/node_modules/smart-buffer/typings/utils.d.ts b/server/node_modules/smart-buffer/typings/utils.d.ts
new file mode 100644
index 0000000..b32b4d4
--- /dev/null
+++ b/server/node_modules/smart-buffer/typings/utils.d.ts
@@ -0,0 +1,66 @@
+/// <reference types="node" />
+import { SmartBuffer } from './smartbuffer';
+import { Buffer } from 'buffer';
+/**
+ * Error strings
+ */
+declare const ERRORS: {
+    INVALID_ENCODING: string;
+    INVALID_SMARTBUFFER_SIZE: string;
+    INVALID_SMARTBUFFER_BUFFER: string;
+    INVALID_SMARTBUFFER_OBJECT: string;
+    INVALID_OFFSET: string;
+    INVALID_OFFSET_NON_NUMBER: string;
+    INVALID_LENGTH: string;
+    INVALID_LENGTH_NON_NUMBER: string;
+    INVALID_TARGET_OFFSET: string;
+    INVALID_TARGET_LENGTH: string;
+    INVALID_READ_BEYOND_BOUNDS: string;
+    INVALID_WRITE_BEYOND_BOUNDS: string;
+};
+/**
+ * Checks if a given encoding is a valid Buffer encoding. (Throws an exception if check fails)
+ *
+ * @param { String } encoding The encoding string to check.
+ */
+declare function checkEncoding(encoding: BufferEncoding): void;
+/**
+ * Checks if a given number is a finite integer. (Throws an exception if check fails)
+ *
+ * @param { Number } value The number value to check.
+ */
+declare function isFiniteInteger(value: number): boolean;
+/**
+ * Checks if a length value is valid. (Throws an exception if check fails)
+ *
+ * @param { Number } length The value to check.
+ */
+declare function checkLengthValue(length: any): void;
+/**
+ * Checks if a offset value is valid. (Throws an exception if check fails)
+ *
+ * @param { Number } offset The value to check.
+ */
+declare function checkOffsetValue(offset: any): void;
+/**
+ * Checks if a target offset value is out of bounds. (Throws an exception if check fails)
+ *
+ * @param { Number } offset The offset value to check.
+ * @param { SmartBuffer } buff The SmartBuffer instance to check against.
+ */
+declare function checkTargetOffset(offset: number, buff: SmartBuffer): void;
+interface Buffer {
+    readBigInt64BE(offset?: number): bigint;
+    readBigInt64LE(offset?: number): bigint;
+    readBigUInt64BE(offset?: number): bigint;
+    readBigUInt64LE(offset?: number): bigint;
+    writeBigInt64BE(value: bigint, offset?: number): number;
+    writeBigInt64LE(value: bigint, offset?: number): number;
+    writeBigUInt64BE(value: bigint, offset?: number): number;
+    writeBigUInt64LE(value: bigint, offset?: number): number;
+}
+/**
+ * Throws if Node.js version is too low to support bigint
+ */
+declare function bigIntAndBufferInt64Check(bufferMethod: keyof Buffer): void;
+export { ERRORS, isFiniteInteger, checkEncoding, checkOffsetValue, checkLengthValue, checkTargetOffset, bigIntAndBufferInt64Check };
diff --git a/server/node_modules/socks-proxy-agent/README.md b/server/node_modules/socks-proxy-agent/README.md
new file mode 100644
index 0000000..2c44170
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/README.md
@@ -0,0 +1,152 @@
+socks-proxy-agent
+================
+### A SOCKS proxy `http.Agent` implementation for HTTP and HTTPS
+[![Build Status](https://github.com/TooTallNate/node-socks-proxy-agent/workflows/Node%20CI/badge.svg)](https://github.com/TooTallNate/node-socks-proxy-agent/actions?workflow=Node+CI)
+
+This module provides an `http.Agent` implementation that connects to a
+specified SOCKS proxy server, and can be used with the built-in `http`
+and `https` modules.
+
+It can also be used in conjunction with the `ws` module to establish a WebSocket
+connection over a SOCKS proxy. See the "Examples" section below.
+
+Installation
+------------
+
+Install with `npm`:
+
+``` bash
+npm install socks-proxy-agent
+```
+
+
+Examples
+--------
+
+#### TypeScript example
+
+```ts
+import https from 'https';
+import { SocksProxyAgent } from 'socks-proxy-agent';
+
+const info = {
+	hostname: 'br41.nordvpn.com',
+	userId: 'your-name@gmail.com',
+	password: 'abcdef12345124'
+};
+const agent = new SocksProxyAgent(info);
+
+https.get('https://ipinfo.io', { agent }, (res) => {
+	console.log(res.headers);
+	res.pipe(process.stdout);
+});
+```
+
+#### `http` module example
+
+```js
+var url = require('url');
+var http = require('http');
+var { SocksProxyAgent } = require('socks-proxy-agent');
+
+// SOCKS proxy to connect to
+var proxy = process.env.socks_proxy || 'socks://127.0.0.1:1080';
+console.log('using proxy server %j', proxy);
+
+// HTTP endpoint for the proxy to connect to
+var endpoint = process.argv[2] || 'http://nodejs.org/api/';
+console.log('attempting to GET %j', endpoint);
+var opts = url.parse(endpoint);
+
+// create an instance of the `SocksProxyAgent` class with the proxy server information
+var agent = new SocksProxyAgent(proxy);
+opts.agent = agent;
+
+http.get(opts, function (res) {
+	console.log('"response" event!', res.headers);
+	res.pipe(process.stdout);
+});
+```
+
+#### `https` module example
+
+```js
+var url = require('url');
+var https = require('https');
+var { SocksProxyAgent } = require('socks-proxy-agent');
+
+// SOCKS proxy to connect to
+var proxy = process.env.socks_proxy || 'socks://127.0.0.1:1080';
+console.log('using proxy server %j', proxy);
+
+// HTTP endpoint for the proxy to connect to
+var endpoint = process.argv[2] || 'https://encrypted.google.com/';
+console.log('attempting to GET %j', endpoint);
+var opts = url.parse(endpoint);
+
+// create an instance of the `SocksProxyAgent` class with the proxy server information
+var agent = new SocksProxyAgent(proxy);
+opts.agent = agent;
+
+https.get(opts, function (res) {
+	console.log('"response" event!', res.headers);
+	res.pipe(process.stdout);
+});
+```
+
+#### `ws` WebSocket connection example
+
+``` js
+var WebSocket = require('ws');
+var { SocksProxyAgent } = require('socks-proxy-agent');
+
+// SOCKS proxy to connect to
+var proxy = process.env.socks_proxy || 'socks://127.0.0.1:1080';
+console.log('using proxy server %j', proxy);
+
+// WebSocket endpoint for the proxy to connect to
+var endpoint = process.argv[2] || 'ws://echo.websocket.org';
+console.log('attempting to connect to WebSocket %j', endpoint);
+
+// create an instance of the `SocksProxyAgent` class with the proxy server information
+var agent = new SocksProxyAgent(proxy);
+
+// initiate the WebSocket connection
+var socket = new WebSocket(endpoint, { agent: agent });
+
+socket.on('open', function () {
+	console.log('"open" event!');
+	socket.send('hello world');
+});
+
+socket.on('message', function (data, flags) {
+	console.log('"message" event! %j %j', data, flags);
+	socket.close();
+});
+```
+
+License
+-------
+
+(The MIT License)
+
+Copyright (c) 2013 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/socks-proxy-agent/dist/index.d.ts b/server/node_modules/socks-proxy-agent/dist/index.d.ts
new file mode 100644
index 0000000..20dc42f
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/dist/index.d.ts
@@ -0,0 +1,38 @@
+/// <reference types="node" />
+import { SocksProxy } from 'socks';
+import { Agent, ClientRequest, RequestOptions } from 'agent-base';
+import { AgentOptions } from 'agent-base';
+import { Url } from 'url';
+import net from 'net';
+import tls from 'tls';
+interface BaseSocksProxyAgentOptions {
+    /**
+     * hostname is preferred over host
+     *
+     * @deprecated
+     */
+    host?: string | null;
+    port?: string | number | null;
+    username?: string | null;
+    tls?: tls.ConnectionOptions | null;
+}
+interface SocksProxyAgentOptionsExtra {
+    timeout?: number;
+}
+export interface SocksProxyAgentOptions extends AgentOptions, BaseSocksProxyAgentOptions, Partial<Omit<Url & SocksProxy, keyof BaseSocksProxyAgentOptions>> {
+}
+export declare class SocksProxyAgent extends Agent {
+    private readonly shouldLookup;
+    private readonly proxy;
+    private readonly tlsConnectionOptions;
+    timeout: number | null;
+    constructor(input: string | SocksProxyAgentOptions, options?: SocksProxyAgentOptionsExtra);
+    /**
+     * Initiates a SOCKS connection to the specified SOCKS proxy server,
+     * which in turn connects to the specified remote host and port.
+     *
+     * @api protected
+     */
+    callback(req: ClientRequest, opts: RequestOptions): Promise<net.Socket>;
+}
+export {};
diff --git a/server/node_modules/socks-proxy-agent/dist/index.js b/server/node_modules/socks-proxy-agent/dist/index.js
new file mode 100644
index 0000000..f615034
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/dist/index.js
@@ -0,0 +1,197 @@
+"use strict";
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.SocksProxyAgent = void 0;
+const socks_1 = require("socks");
+const agent_base_1 = require("agent-base");
+const debug_1 = __importDefault(require("debug"));
+const dns_1 = __importDefault(require("dns"));
+const tls_1 = __importDefault(require("tls"));
+const debug = (0, debug_1.default)('socks-proxy-agent');
+function parseSocksProxy(opts) {
+    var _a;
+    let port = 0;
+    let lookup = false;
+    let type = 5;
+    const host = opts.hostname || opts.host;
+    if (host == null) {
+        throw new TypeError('No "hostname"');
+    }
+    if (typeof opts.port === 'number') {
+        port = opts.port;
+    }
+    else if (typeof opts.port === 'string') {
+        port = parseInt(opts.port, 10);
+    }
+    // From RFC 1928, Section 3: https://tools.ietf.org/html/rfc1928#section-3
+    // "The SOCKS service is conventionally located on TCP port 1080"
+    if (port == null) {
+        port = 1080;
+    }
+    // figure out if we want socks v4 or v5, based on the "protocol" used.
+    // Defaults to 5.
+    if (opts.protocol != null) {
+        switch (opts.protocol.replace(':', '')) {
+            case 'socks4':
+                lookup = true;
+            // pass through
+            case 'socks4a':
+                type = 4;
+                break;
+            case 'socks5':
+                lookup = true;
+            // pass through
+            case 'socks': // no version specified, default to 5h
+            case 'socks5h':
+                type = 5;
+                break;
+            default:
+                throw new TypeError(`A "socks" protocol must be specified! Got: ${String(opts.protocol)}`);
+        }
+    }
+    if (typeof opts.type !== 'undefined') {
+        if (opts.type === 4 || opts.type === 5) {
+            type = opts.type;
+        }
+        else {
+            throw new TypeError(`"type" must be 4 or 5, got: ${String(opts.type)}`);
+        }
+    }
+    const proxy = {
+        host,
+        port,
+        type
+    };
+    let userId = (_a = opts.userId) !== null && _a !== void 0 ? _a : opts.username;
+    let password = opts.password;
+    if (opts.auth != null) {
+        const auth = opts.auth.split(':');
+        userId = auth[0];
+        password = auth[1];
+    }
+    if (userId != null) {
+        Object.defineProperty(proxy, 'userId', {
+            value: userId,
+            enumerable: false
+        });
+    }
+    if (password != null) {
+        Object.defineProperty(proxy, 'password', {
+            value: password,
+            enumerable: false
+        });
+    }
+    return { lookup, proxy };
+}
+const normalizeProxyOptions = (input) => {
+    let proxyOptions;
+    if (typeof input === 'string') {
+        proxyOptions = new URL(input);
+    }
+    else {
+        proxyOptions = input;
+    }
+    if (proxyOptions == null) {
+        throw new TypeError('a SOCKS proxy server `hostname` and `port` must be specified!');
+    }
+    return proxyOptions;
+};
+class SocksProxyAgent extends agent_base_1.Agent {
+    constructor(input, options) {
+        var _a;
+        const proxyOptions = normalizeProxyOptions(input);
+        super(proxyOptions);
+        const parsedProxy = parseSocksProxy(proxyOptions);
+        this.shouldLookup = parsedProxy.lookup;
+        this.proxy = parsedProxy.proxy;
+        this.tlsConnectionOptions = proxyOptions.tls != null ? proxyOptions.tls : {};
+        this.timeout = (_a = options === null || options === void 0 ? void 0 : options.timeout) !== null && _a !== void 0 ? _a : null;
+    }
+    /**
+     * Initiates a SOCKS connection to the specified SOCKS proxy server,
+     * which in turn connects to the specified remote host and port.
+     *
+     * @api protected
+     */
+    callback(req, opts) {
+        var _a;
+        return __awaiter(this, void 0, void 0, function* () {
+            const { shouldLookup, proxy, timeout } = this;
+            let { host, port, lookup: lookupCallback } = opts;
+            if (host == null) {
+                throw new Error('No `host` defined!');
+            }
+            if (shouldLookup) {
+                // Client-side DNS resolution for "4" and "5" socks proxy versions.
+                host = yield new Promise((resolve, reject) => {
+                    // Use the request's custom lookup, if one was configured:
+                    const lookupFn = lookupCallback !== null && lookupCallback !== void 0 ? lookupCallback : dns_1.default.lookup;
+                    lookupFn(host, {}, (err, res) => {
+                        if (err) {
+                            reject(err);
+                        }
+                        else {
+                            resolve(res);
+                        }
+                    });
+                });
+            }
+            const socksOpts = {
+                proxy,
+                destination: { host, port },
+                command: 'connect',
+                timeout: timeout !== null && timeout !== void 0 ? timeout : undefined
+            };
+            const cleanup = (tlsSocket) => {
+                req.destroy();
+                socket.destroy();
+                if (tlsSocket)
+                    tlsSocket.destroy();
+            };
+            debug('Creating socks proxy connection: %o', socksOpts);
+            const { socket } = yield socks_1.SocksClient.createConnection(socksOpts);
+            debug('Successfully created socks proxy connection');
+            if (timeout !== null) {
+                socket.setTimeout(timeout);
+                socket.on('timeout', () => cleanup());
+            }
+            if (opts.secureEndpoint) {
+                // The proxy is connecting to a TLS server, so upgrade
+                // this socket connection to a TLS connection.
+                debug('Upgrading socket connection to TLS');
+                const servername = (_a = opts.servername) !== null && _a !== void 0 ? _a : opts.host;
+                const tlsSocket = tls_1.default.connect(Object.assign(Object.assign(Object.assign({}, omit(opts, 'host', 'hostname', 'path', 'port')), { socket,
+                    servername }), this.tlsConnectionOptions));
+                tlsSocket.once('error', (error) => {
+                    debug('socket TLS error', error.message);
+                    cleanup(tlsSocket);
+                });
+                return tlsSocket;
+            }
+            return socket;
+        });
+    }
+}
+exports.SocksProxyAgent = SocksProxyAgent;
+function omit(obj, ...keys) {
+    const ret = {};
+    let key;
+    for (key in obj) {
+        if (!keys.includes(key)) {
+            ret[key] = obj[key];
+        }
+    }
+    return ret;
+}
+//# sourceMappingURL=index.js.map
\ No newline at end of file
diff --git a/server/node_modules/socks-proxy-agent/dist/index.js.map b/server/node_modules/socks-proxy-agent/dist/index.js.map
new file mode 100644
index 0000000..96d8fab
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/dist/index.js.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/server/node_modules/socks-proxy-agent/node_modules/debug/LICENSE b/server/node_modules/socks-proxy-agent/node_modules/debug/LICENSE
new file mode 100644
index 0000000..1a9820e
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/debug/LICENSE
@@ -0,0 +1,20 @@
+(The MIT License)
+
+Copyright (c) 2014-2017 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2018-2021 Josh Junon
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+and associated documentation files (the 'Software'), to deal in the Software without restriction,
+including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial
+portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
+LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
diff --git a/server/node_modules/socks-proxy-agent/node_modules/debug/README.md b/server/node_modules/socks-proxy-agent/node_modules/debug/README.md
new file mode 100644
index 0000000..9ebdfbf
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/debug/README.md
@@ -0,0 +1,481 @@
+# debug
+[![OpenCollective](https://opencollective.com/debug/backers/badge.svg)](#backers)
+[![OpenCollective](https://opencollective.com/debug/sponsors/badge.svg)](#sponsors)
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091486-fa38524c-7c37-11e7-895f-e7ec8e1039b6.png">
+
+A tiny JavaScript debugging utility modelled after Node.js core's debugging
+technique. Works in Node.js and web browsers.
+
+## Installation
+
+```bash
+$ npm install debug
+```
+
+## Usage
+
+`debug` exposes a function; simply pass this function the name of your module, and it will return a decorated version of `console.error` for you to pass debug statements to. This will allow you to toggle the debug output for different parts of your module as well as the module as a whole.
+
+Example [_app.js_](./examples/node/app.js):
+
+```js
+var debug = require('debug')('http')
+  , http = require('http')
+  , name = 'My App';
+
+// fake app
+
+debug('booting %o', name);
+
+http.createServer(function(req, res){
+  debug(req.method + ' ' + req.url);
+  res.end('hello\n');
+}).listen(3000, function(){
+  debug('listening');
+});
+
+// fake worker of some kind
+
+require('./worker');
+```
+
+Example [_worker.js_](./examples/node/worker.js):
+
+```js
+var a = require('debug')('worker:a')
+  , b = require('debug')('worker:b');
+
+function work() {
+  a('doing lots of uninteresting work');
+  setTimeout(work, Math.random() * 1000);
+}
+
+work();
+
+function workb() {
+  b('doing some work');
+  setTimeout(workb, Math.random() * 2000);
+}
+
+workb();
+```
+
+The `DEBUG` environment variable is then used to enable these based on space or
+comma-delimited names.
+
+Here are some examples:
+
+<img width="647" alt="screen shot 2017-08-08 at 12 53 04 pm" src="https://user-images.githubusercontent.com/71256/29091703-a6302cdc-7c38-11e7-8304-7c0b3bc600cd.png">
+<img width="647" alt="screen shot 2017-08-08 at 12 53 38 pm" src="https://user-images.githubusercontent.com/71256/29091700-a62a6888-7c38-11e7-800b-db911291ca2b.png">
+<img width="647" alt="screen shot 2017-08-08 at 12 53 25 pm" src="https://user-images.githubusercontent.com/71256/29091701-a62ea114-7c38-11e7-826a-2692bedca740.png">
+
+#### Windows command prompt notes
+
+##### CMD
+
+On Windows the environment variable is set using the `set` command.
+
+```cmd
+set DEBUG=*,-not_this
+```
+
+Example:
+
+```cmd
+set DEBUG=* & node app.js
+```
+
+##### PowerShell (VS Code default)
+
+PowerShell uses different syntax to set environment variables.
+
+```cmd
+$env:DEBUG = "*,-not_this"
+```
+
+Example:
+
+```cmd
+$env:DEBUG='app';node app.js
+```
+
+Then, run the program to be debugged as usual.
+
+npm script example:
+```js
+  "windowsDebug": "@powershell -Command $env:DEBUG='*';node app.js",
+```
+
+## Namespace Colors
+
+Every debug instance has a color generated for it based on its namespace name.
+This helps when visually parsing the debug output to identify which debug instance
+a debug line belongs to.
+
+#### Node.js
+
+In Node.js, colors are enabled when stderr is a TTY. You also _should_ install
+the [`supports-color`](https://npmjs.org/supports-color) module alongside debug,
+otherwise debug will only use a small handful of basic colors.
+
+<img width="521" src="https://user-images.githubusercontent.com/71256/29092181-47f6a9e6-7c3a-11e7-9a14-1928d8a711cd.png">
+
+#### Web Browser
+
+Colors are also enabled on "Web Inspectors" that understand the `%c` formatting
+option. These are WebKit web inspectors, Firefox ([since version
+31](https://hacks.mozilla.org/2014/05/editable-box-model-multiple-selection-sublime-text-keys-much-more-firefox-developer-tools-episode-31/))
+and the Firebug plugin for Firefox (any version).
+
+<img width="524" src="https://user-images.githubusercontent.com/71256/29092033-b65f9f2e-7c39-11e7-8e32-f6f0d8e865c1.png">
+
+
+## Millisecond diff
+
+When actively developing an application it can be useful to see when the time spent between one `debug()` call and the next. Suppose for example you invoke `debug()` before requesting a resource, and after as well, the "+NNNms" will show you how much time was spent between calls.
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091486-fa38524c-7c37-11e7-895f-e7ec8e1039b6.png">
+
+When stdout is not a TTY, `Date#toISOString()` is used, making it more useful for logging the debug information as shown below:
+
+<img width="647" src="https://user-images.githubusercontent.com/71256/29091956-6bd78372-7c39-11e7-8c55-c948396d6edd.png">
+
+
+## Conventions
+
+If you're using this in one or more of your libraries, you _should_ use the name of your library so that developers may toggle debugging as desired without guessing names. If you have more than one debuggers you _should_ prefix them with your library name and use ":" to separate features. For example "bodyParser" from Connect would then be "connect:bodyParser".  If you append a "*" to the end of your name, it will always be enabled regardless of the setting of the DEBUG environment variable.  You can then use it for normal output as well as debug output.
+
+## Wildcards
+
+The `*` character may be used as a wildcard. Suppose for example your library has
+debuggers named "connect:bodyParser", "connect:compress", "connect:session",
+instead of listing all three with
+`DEBUG=connect:bodyParser,connect:compress,connect:session`, you may simply do
+`DEBUG=connect:*`, or to run everything using this module simply use `DEBUG=*`.
+
+You can also exclude specific debuggers by prefixing them with a "-" character.
+For example, `DEBUG=*,-connect:*` would include all debuggers except those
+starting with "connect:".
+
+## Environment Variables
+
+When running through Node.js, you can set a few environment variables that will
+change the behavior of the debug logging:
+
+| Name      | Purpose                                         |
+|-----------|-------------------------------------------------|
+| `DEBUG`   | Enables/disables specific debugging namespaces. |
+| `DEBUG_HIDE_DATE` | Hide date from debug output (non-TTY).  |
+| `DEBUG_COLORS`| Whether or not to use colors in the debug output. |
+| `DEBUG_DEPTH` | Object inspection depth.                    |
+| `DEBUG_SHOW_HIDDEN` | Shows hidden properties on inspected objects. |
+
+
+__Note:__ The environment variables beginning with `DEBUG_` end up being
+converted into an Options object that gets used with `%o`/`%O` formatters.
+See the Node.js documentation for
+[`util.inspect()`](https://nodejs.org/api/util.html#util_util_inspect_object_options)
+for the complete list.
+
+## Formatters
+
+Debug uses [printf-style](https://wikipedia.org/wiki/Printf_format_string) formatting.
+Below are the officially supported formatters:
+
+| Formatter | Representation |
+|-----------|----------------|
+| `%O`      | Pretty-print an Object on multiple lines. |
+| `%o`      | Pretty-print an Object all on a single line. |
+| `%s`      | String. |
+| `%d`      | Number (both integer and float). |
+| `%j`      | JSON. Replaced with the string '[Circular]' if the argument contains circular references. |
+| `%%`      | Single percent sign ('%'). This does not consume an argument. |
+
+
+### Custom formatters
+
+You can add custom formatters by extending the `debug.formatters` object.
+For example, if you wanted to add support for rendering a Buffer as hex with
+`%h`, you could do something like:
+
+```js
+const createDebug = require('debug')
+createDebug.formatters.h = (v) => {
+  return v.toString('hex')
+}
+
+// …elsewhere
+const debug = createDebug('foo')
+debug('this is hex: %h', new Buffer('hello world'))
+//   foo this is hex: 68656c6c6f20776f726c6421 +0ms
+```
+
+
+## Browser Support
+
+You can build a browser-ready script using [browserify](https://github.com/substack/node-browserify),
+or just use the [browserify-as-a-service](https://wzrd.in/) [build](https://wzrd.in/standalone/debug@latest),
+if you don't want to build it yourself.
+
+Debug's enable state is currently persisted by `localStorage`.
+Consider the situation shown below where you have `worker:a` and `worker:b`,
+and wish to debug both. You can enable this using `localStorage.debug`:
+
+```js
+localStorage.debug = 'worker:*'
+```
+
+And then refresh the page.
+
+```js
+a = debug('worker:a');
+b = debug('worker:b');
+
+setInterval(function(){
+  a('doing some work');
+}, 1000);
+
+setInterval(function(){
+  b('doing some work');
+}, 1200);
+```
+
+In Chromium-based web browsers (e.g. Brave, Chrome, and Electron), the JavaScript console will—by default—only show messages logged by `debug` if the "Verbose" log level is _enabled_.
+
+<img width="647" src="https://user-images.githubusercontent.com/7143133/152083257-29034707-c42c-4959-8add-3cee850e6fcf.png">
+
+## Output streams
+
+  By default `debug` will log to stderr, however this can be configured per-namespace by overriding the `log` method:
+
+Example [_stdout.js_](./examples/node/stdout.js):
+
+```js
+var debug = require('debug');
+var error = debug('app:error');
+
+// by default stderr is used
+error('goes to stderr!');
+
+var log = debug('app:log');
+// set this namespace to log via console.log
+log.log = console.log.bind(console); // don't forget to bind to console!
+log('goes to stdout');
+error('still goes to stderr!');
+
+// set all output to go via console.info
+// overrides all per-namespace log settings
+debug.log = console.info.bind(console);
+error('now goes to stdout via console.info');
+log('still goes to stdout, but via console.info now');
+```
+
+## Extend
+You can simply extend debugger 
+```js
+const log = require('debug')('auth');
+
+//creates new debug instance with extended namespace
+const logSign = log.extend('sign');
+const logLogin = log.extend('login');
+
+log('hello'); // auth hello
+logSign('hello'); //auth:sign hello
+logLogin('hello'); //auth:login hello
+```
+
+## Set dynamically
+
+You can also enable debug dynamically by calling the `enable()` method :
+
+```js
+let debug = require('debug');
+
+console.log(1, debug.enabled('test'));
+
+debug.enable('test');
+console.log(2, debug.enabled('test'));
+
+debug.disable();
+console.log(3, debug.enabled('test'));
+
+```
+
+print :   
+```
+1 false
+2 true
+3 false
+```
+
+Usage :  
+`enable(namespaces)`  
+`namespaces` can include modes separated by a colon and wildcards.
+   
+Note that calling `enable()` completely overrides previously set DEBUG variable : 
+
+```
+$ DEBUG=foo node -e 'var dbg = require("debug"); dbg.enable("bar"); console.log(dbg.enabled("foo"))'
+=> false
+```
+
+`disable()`
+
+Will disable all namespaces. The functions returns the namespaces currently
+enabled (and skipped). This can be useful if you want to disable debugging
+temporarily without knowing what was enabled to begin with.
+
+For example:
+
+```js
+let debug = require('debug');
+debug.enable('foo:*,-foo:bar');
+let namespaces = debug.disable();
+debug.enable(namespaces);
+```
+
+Note: There is no guarantee that the string will be identical to the initial
+enable string, but semantically they will be identical.
+
+## Checking whether a debug target is enabled
+
+After you've created a debug instance, you can determine whether or not it is
+enabled by checking the `enabled` property:
+
+```javascript
+const debug = require('debug')('http');
+
+if (debug.enabled) {
+  // do stuff...
+}
+```
+
+You can also manually toggle this property to force the debug instance to be
+enabled or disabled.
+
+## Usage in child processes
+
+Due to the way `debug` detects if the output is a TTY or not, colors are not shown in child processes when `stderr` is piped. A solution is to pass the `DEBUG_COLORS=1` environment variable to the child process.  
+For example:
+
+```javascript
+worker = fork(WORKER_WRAP_PATH, [workerPath], {
+  stdio: [
+    /* stdin: */ 0,
+    /* stdout: */ 'pipe',
+    /* stderr: */ 'pipe',
+    'ipc',
+  ],
+  env: Object.assign({}, process.env, {
+    DEBUG_COLORS: 1 // without this settings, colors won't be shown
+  }),
+});
+
+worker.stderr.pipe(process.stderr, { end: false });
+```
+
+
+## Authors
+
+ - TJ Holowaychuk
+ - Nathan Rajlich
+ - Andrew Rhyne
+ - Josh Junon
+
+## Backers
+
+Support us with a monthly donation and help us continue our activities. [[Become a backer](https://opencollective.com/debug#backer)]
+
+<a href="https://opencollective.com/debug/backer/0/website" target="_blank"><img src="https://opencollective.com/debug/backer/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/1/website" target="_blank"><img src="https://opencollective.com/debug/backer/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/2/website" target="_blank"><img src="https://opencollective.com/debug/backer/2/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/3/website" target="_blank"><img src="https://opencollective.com/debug/backer/3/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/4/website" target="_blank"><img src="https://opencollective.com/debug/backer/4/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/5/website" target="_blank"><img src="https://opencollective.com/debug/backer/5/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/6/website" target="_blank"><img src="https://opencollective.com/debug/backer/6/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/7/website" target="_blank"><img src="https://opencollective.com/debug/backer/7/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/8/website" target="_blank"><img src="https://opencollective.com/debug/backer/8/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/9/website" target="_blank"><img src="https://opencollective.com/debug/backer/9/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/10/website" target="_blank"><img src="https://opencollective.com/debug/backer/10/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/11/website" target="_blank"><img src="https://opencollective.com/debug/backer/11/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/12/website" target="_blank"><img src="https://opencollective.com/debug/backer/12/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/13/website" target="_blank"><img src="https://opencollective.com/debug/backer/13/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/14/website" target="_blank"><img src="https://opencollective.com/debug/backer/14/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/15/website" target="_blank"><img src="https://opencollective.com/debug/backer/15/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/16/website" target="_blank"><img src="https://opencollective.com/debug/backer/16/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/17/website" target="_blank"><img src="https://opencollective.com/debug/backer/17/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/18/website" target="_blank"><img src="https://opencollective.com/debug/backer/18/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/19/website" target="_blank"><img src="https://opencollective.com/debug/backer/19/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/20/website" target="_blank"><img src="https://opencollective.com/debug/backer/20/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/21/website" target="_blank"><img src="https://opencollective.com/debug/backer/21/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/22/website" target="_blank"><img src="https://opencollective.com/debug/backer/22/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/23/website" target="_blank"><img src="https://opencollective.com/debug/backer/23/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/24/website" target="_blank"><img src="https://opencollective.com/debug/backer/24/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/25/website" target="_blank"><img src="https://opencollective.com/debug/backer/25/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/26/website" target="_blank"><img src="https://opencollective.com/debug/backer/26/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/27/website" target="_blank"><img src="https://opencollective.com/debug/backer/27/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/28/website" target="_blank"><img src="https://opencollective.com/debug/backer/28/avatar.svg"></a>
+<a href="https://opencollective.com/debug/backer/29/website" target="_blank"><img src="https://opencollective.com/debug/backer/29/avatar.svg"></a>
+
+
+## Sponsors
+
+Become a sponsor and get your logo on our README on Github with a link to your site. [[Become a sponsor](https://opencollective.com/debug#sponsor)]
+
+<a href="https://opencollective.com/debug/sponsor/0/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/0/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/1/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/1/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/2/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/2/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/3/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/3/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/4/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/4/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/5/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/5/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/6/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/6/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/7/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/7/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/8/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/8/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/9/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/9/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/10/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/10/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/11/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/11/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/12/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/12/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/13/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/13/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/14/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/14/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/15/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/15/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/16/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/16/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/17/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/17/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/18/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/18/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/19/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/19/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/20/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/20/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/21/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/21/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/22/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/22/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/23/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/23/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/24/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/24/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/25/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/25/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/26/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/26/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/27/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/27/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/28/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/28/avatar.svg"></a>
+<a href="https://opencollective.com/debug/sponsor/29/website" target="_blank"><img src="https://opencollective.com/debug/sponsor/29/avatar.svg"></a>
+
+## License
+
+(The MIT License)
+
+Copyright (c) 2014-2017 TJ Holowaychuk <tj@vision-media.ca>
+Copyright (c) 2018-2021 Josh Junon
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/socks-proxy-agent/node_modules/debug/package.json b/server/node_modules/socks-proxy-agent/node_modules/debug/package.json
new file mode 100644
index 0000000..ee8abb5
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/debug/package.json
@@ -0,0 +1,64 @@
+{
+  "name": "debug",
+  "version": "4.4.3",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/debug-js/debug.git"
+  },
+  "description": "Lightweight debugging utility for Node.js and the browser",
+  "keywords": [
+    "debug",
+    "log",
+    "debugger"
+  ],
+  "files": [
+    "src",
+    "LICENSE",
+    "README.md"
+  ],
+  "author": "Josh Junon (https://github.com/qix-)",
+  "contributors": [
+    "TJ Holowaychuk <tj@vision-media.ca>",
+    "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io)",
+    "Andrew Rhyne <rhyneandrew@gmail.com>"
+  ],
+  "license": "MIT",
+  "scripts": {
+    "lint": "xo",
+    "test": "npm run test:node && npm run test:browser && npm run lint",
+    "test:node": "mocha test.js test.node.js",
+    "test:browser": "karma start --single-run",
+    "test:coverage": "cat ./coverage/lcov.info | coveralls"
+  },
+  "dependencies": {
+    "ms": "^2.1.3"
+  },
+  "devDependencies": {
+    "brfs": "^2.0.1",
+    "browserify": "^16.2.3",
+    "coveralls": "^3.0.2",
+    "karma": "^3.1.4",
+    "karma-browserify": "^6.0.0",
+    "karma-chrome-launcher": "^2.2.0",
+    "karma-mocha": "^1.3.0",
+    "mocha": "^5.2.0",
+    "mocha-lcov-reporter": "^1.2.0",
+    "sinon": "^14.0.0",
+    "xo": "^0.23.0"
+  },
+  "peerDependenciesMeta": {
+    "supports-color": {
+      "optional": true
+    }
+  },
+  "main": "./src/index.js",
+  "browser": "./src/browser.js",
+  "engines": {
+    "node": ">=6.0"
+  },
+  "xo": {
+    "rules": {
+      "import/extensions": "off"
+    }
+  }
+}
diff --git a/server/node_modules/socks-proxy-agent/node_modules/debug/src/browser.js b/server/node_modules/socks-proxy-agent/node_modules/debug/src/browser.js
new file mode 100644
index 0000000..5993451
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/debug/src/browser.js
@@ -0,0 +1,272 @@
+/* eslint-env browser */
+
+/**
+ * This is the web browser implementation of `debug()`.
+ */
+
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+exports.storage = localstorage();
+exports.destroy = (() => {
+	let warned = false;
+
+	return () => {
+		if (!warned) {
+			warned = true;
+			console.warn('Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.');
+		}
+	};
+})();
+
+/**
+ * Colors.
+ */
+
+exports.colors = [
+	'#0000CC',
+	'#0000FF',
+	'#0033CC',
+	'#0033FF',
+	'#0066CC',
+	'#0066FF',
+	'#0099CC',
+	'#0099FF',
+	'#00CC00',
+	'#00CC33',
+	'#00CC66',
+	'#00CC99',
+	'#00CCCC',
+	'#00CCFF',
+	'#3300CC',
+	'#3300FF',
+	'#3333CC',
+	'#3333FF',
+	'#3366CC',
+	'#3366FF',
+	'#3399CC',
+	'#3399FF',
+	'#33CC00',
+	'#33CC33',
+	'#33CC66',
+	'#33CC99',
+	'#33CCCC',
+	'#33CCFF',
+	'#6600CC',
+	'#6600FF',
+	'#6633CC',
+	'#6633FF',
+	'#66CC00',
+	'#66CC33',
+	'#9900CC',
+	'#9900FF',
+	'#9933CC',
+	'#9933FF',
+	'#99CC00',
+	'#99CC33',
+	'#CC0000',
+	'#CC0033',
+	'#CC0066',
+	'#CC0099',
+	'#CC00CC',
+	'#CC00FF',
+	'#CC3300',
+	'#CC3333',
+	'#CC3366',
+	'#CC3399',
+	'#CC33CC',
+	'#CC33FF',
+	'#CC6600',
+	'#CC6633',
+	'#CC9900',
+	'#CC9933',
+	'#CCCC00',
+	'#CCCC33',
+	'#FF0000',
+	'#FF0033',
+	'#FF0066',
+	'#FF0099',
+	'#FF00CC',
+	'#FF00FF',
+	'#FF3300',
+	'#FF3333',
+	'#FF3366',
+	'#FF3399',
+	'#FF33CC',
+	'#FF33FF',
+	'#FF6600',
+	'#FF6633',
+	'#FF9900',
+	'#FF9933',
+	'#FFCC00',
+	'#FFCC33'
+];
+
+/**
+ * Currently only WebKit-based Web Inspectors, Firefox >= v31,
+ * and the Firebug extension (any Firefox version) are known
+ * to support "%c" CSS customizations.
+ *
+ * TODO: add a `localStorage` variable to explicitly enable/disable colors
+ */
+
+// eslint-disable-next-line complexity
+function useColors() {
+	// NB: In an Electron preload script, document will be defined but not fully
+	// initialized. Since we know we're in Chrome, we'll just detect this case
+	// explicitly
+	if (typeof window !== 'undefined' && window.process && (window.process.type === 'renderer' || window.process.__nwjs)) {
+		return true;
+	}
+
+	// Internet Explorer and Edge do not support colors.
+	if (typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/(edge|trident)\/(\d+)/)) {
+		return false;
+	}
+
+	let m;
+
+	// Is webkit? http://stackoverflow.com/a/16459606/376773
+	// document is undefined in react-native: https://github.com/facebook/react-native/pull/1632
+	// eslint-disable-next-line no-return-assign
+	return (typeof document !== 'undefined' && document.documentElement && document.documentElement.style && document.documentElement.style.WebkitAppearance) ||
+		// Is firebug? http://stackoverflow.com/a/398120/376773
+		(typeof window !== 'undefined' && window.console && (window.console.firebug || (window.console.exception && window.console.table))) ||
+		// Is firefox >= v31?
+		// https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
+		(typeof navigator !== 'undefined' && navigator.userAgent && (m = navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/)) && parseInt(m[1], 10) >= 31) ||
+		// Double check webkit in userAgent just in case we are in a worker
+		(typeof navigator !== 'undefined' && navigator.userAgent && navigator.userAgent.toLowerCase().match(/applewebkit\/(\d+)/));
+}
+
+/**
+ * Colorize log arguments if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+	args[0] = (this.useColors ? '%c' : '') +
+		this.namespace +
+		(this.useColors ? ' %c' : ' ') +
+		args[0] +
+		(this.useColors ? '%c ' : ' ') +
+		'+' + module.exports.humanize(this.diff);
+
+	if (!this.useColors) {
+		return;
+	}
+
+	const c = 'color: ' + this.color;
+	args.splice(1, 0, c, 'color: inherit');
+
+	// The final "%c" is somewhat tricky, because there could be other
+	// arguments passed either before or after the %c, so we need to
+	// figure out the correct index to insert the CSS into
+	let index = 0;
+	let lastC = 0;
+	args[0].replace(/%[a-zA-Z%]/g, match => {
+		if (match === '%%') {
+			return;
+		}
+		index++;
+		if (match === '%c') {
+			// We only are interested in the *last* %c
+			// (the user may have provided their own)
+			lastC = index;
+		}
+	});
+
+	args.splice(lastC, 0, c);
+}
+
+/**
+ * Invokes `console.debug()` when available.
+ * No-op when `console.debug` is not a "function".
+ * If `console.debug` is not available, falls back
+ * to `console.log`.
+ *
+ * @api public
+ */
+exports.log = console.debug || console.log || (() => {});
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+function save(namespaces) {
+	try {
+		if (namespaces) {
+			exports.storage.setItem('debug', namespaces);
+		} else {
+			exports.storage.removeItem('debug');
+		}
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+function load() {
+	let r;
+	try {
+		r = exports.storage.getItem('debug') || exports.storage.getItem('DEBUG') ;
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+
+	// If debug isn't set in LS, and we're in Electron, try to load $DEBUG
+	if (!r && typeof process !== 'undefined' && 'env' in process) {
+		r = process.env.DEBUG;
+	}
+
+	return r;
+}
+
+/**
+ * Localstorage attempts to return the localstorage.
+ *
+ * This is necessary because safari throws
+ * when a user disables cookies/localstorage
+ * and you attempt to access it.
+ *
+ * @return {LocalStorage}
+ * @api private
+ */
+
+function localstorage() {
+	try {
+		// TVMLKit (Apple TV JS Runtime) does not have a window object, just localStorage in the global context
+		// The Browser also has localStorage in the global context.
+		return localStorage;
+	} catch (error) {
+		// Swallow
+		// XXX (@Qix-) should we be logging these?
+	}
+}
+
+module.exports = require('./common')(exports);
+
+const {formatters} = module.exports;
+
+/**
+ * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
+ */
+
+formatters.j = function (v) {
+	try {
+		return JSON.stringify(v);
+	} catch (error) {
+		return '[UnexpectedJSONParseError]: ' + error.message;
+	}
+};
diff --git a/server/node_modules/socks-proxy-agent/node_modules/debug/src/common.js b/server/node_modules/socks-proxy-agent/node_modules/debug/src/common.js
new file mode 100644
index 0000000..141cb57
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/debug/src/common.js
@@ -0,0 +1,292 @@
+
+/**
+ * This is the common logic for both the Node.js and web browser
+ * implementations of `debug()`.
+ */
+
+function setup(env) {
+	createDebug.debug = createDebug;
+	createDebug.default = createDebug;
+	createDebug.coerce = coerce;
+	createDebug.disable = disable;
+	createDebug.enable = enable;
+	createDebug.enabled = enabled;
+	createDebug.humanize = require('ms');
+	createDebug.destroy = destroy;
+
+	Object.keys(env).forEach(key => {
+		createDebug[key] = env[key];
+	});
+
+	/**
+	* The currently active debug mode names, and names to skip.
+	*/
+
+	createDebug.names = [];
+	createDebug.skips = [];
+
+	/**
+	* Map of special "%n" handling functions, for the debug "format" argument.
+	*
+	* Valid key names are a single, lower or upper-case letter, i.e. "n" and "N".
+	*/
+	createDebug.formatters = {};
+
+	/**
+	* Selects a color for a debug namespace
+	* @param {String} namespace The namespace string for the debug instance to be colored
+	* @return {Number|String} An ANSI color code for the given namespace
+	* @api private
+	*/
+	function selectColor(namespace) {
+		let hash = 0;
+
+		for (let i = 0; i < namespace.length; i++) {
+			hash = ((hash << 5) - hash) + namespace.charCodeAt(i);
+			hash |= 0; // Convert to 32bit integer
+		}
+
+		return createDebug.colors[Math.abs(hash) % createDebug.colors.length];
+	}
+	createDebug.selectColor = selectColor;
+
+	/**
+	* Create a debugger with the given `namespace`.
+	*
+	* @param {String} namespace
+	* @return {Function}
+	* @api public
+	*/
+	function createDebug(namespace) {
+		let prevTime;
+		let enableOverride = null;
+		let namespacesCache;
+		let enabledCache;
+
+		function debug(...args) {
+			// Disabled?
+			if (!debug.enabled) {
+				return;
+			}
+
+			const self = debug;
+
+			// Set `diff` timestamp
+			const curr = Number(new Date());
+			const ms = curr - (prevTime || curr);
+			self.diff = ms;
+			self.prev = prevTime;
+			self.curr = curr;
+			prevTime = curr;
+
+			args[0] = createDebug.coerce(args[0]);
+
+			if (typeof args[0] !== 'string') {
+				// Anything else let's inspect with %O
+				args.unshift('%O');
+			}
+
+			// Apply any `formatters` transformations
+			let index = 0;
+			args[0] = args[0].replace(/%([a-zA-Z%])/g, (match, format) => {
+				// If we encounter an escaped % then don't increase the array index
+				if (match === '%%') {
+					return '%';
+				}
+				index++;
+				const formatter = createDebug.formatters[format];
+				if (typeof formatter === 'function') {
+					const val = args[index];
+					match = formatter.call(self, val);
+
+					// Now we need to remove `args[index]` since it's inlined in the `format`
+					args.splice(index, 1);
+					index--;
+				}
+				return match;
+			});
+
+			// Apply env-specific formatting (colors, etc.)
+			createDebug.formatArgs.call(self, args);
+
+			const logFn = self.log || createDebug.log;
+			logFn.apply(self, args);
+		}
+
+		debug.namespace = namespace;
+		debug.useColors = createDebug.useColors();
+		debug.color = createDebug.selectColor(namespace);
+		debug.extend = extend;
+		debug.destroy = createDebug.destroy; // XXX Temporary. Will be removed in the next major release.
+
+		Object.defineProperty(debug, 'enabled', {
+			enumerable: true,
+			configurable: false,
+			get: () => {
+				if (enableOverride !== null) {
+					return enableOverride;
+				}
+				if (namespacesCache !== createDebug.namespaces) {
+					namespacesCache = createDebug.namespaces;
+					enabledCache = createDebug.enabled(namespace);
+				}
+
+				return enabledCache;
+			},
+			set: v => {
+				enableOverride = v;
+			}
+		});
+
+		// Env-specific initialization logic for debug instances
+		if (typeof createDebug.init === 'function') {
+			createDebug.init(debug);
+		}
+
+		return debug;
+	}
+
+	function extend(namespace, delimiter) {
+		const newDebug = createDebug(this.namespace + (typeof delimiter === 'undefined' ? ':' : delimiter) + namespace);
+		newDebug.log = this.log;
+		return newDebug;
+	}
+
+	/**
+	* Enables a debug mode by namespaces. This can include modes
+	* separated by a colon and wildcards.
+	*
+	* @param {String} namespaces
+	* @api public
+	*/
+	function enable(namespaces) {
+		createDebug.save(namespaces);
+		createDebug.namespaces = namespaces;
+
+		createDebug.names = [];
+		createDebug.skips = [];
+
+		const split = (typeof namespaces === 'string' ? namespaces : '')
+			.trim()
+			.replace(/\s+/g, ',')
+			.split(',')
+			.filter(Boolean);
+
+		for (const ns of split) {
+			if (ns[0] === '-') {
+				createDebug.skips.push(ns.slice(1));
+			} else {
+				createDebug.names.push(ns);
+			}
+		}
+	}
+
+	/**
+	 * Checks if the given string matches a namespace template, honoring
+	 * asterisks as wildcards.
+	 *
+	 * @param {String} search
+	 * @param {String} template
+	 * @return {Boolean}
+	 */
+	function matchesTemplate(search, template) {
+		let searchIndex = 0;
+		let templateIndex = 0;
+		let starIndex = -1;
+		let matchIndex = 0;
+
+		while (searchIndex < search.length) {
+			if (templateIndex < template.length && (template[templateIndex] === search[searchIndex] || template[templateIndex] === '*')) {
+				// Match character or proceed with wildcard
+				if (template[templateIndex] === '*') {
+					starIndex = templateIndex;
+					matchIndex = searchIndex;
+					templateIndex++; // Skip the '*'
+				} else {
+					searchIndex++;
+					templateIndex++;
+				}
+			} else if (starIndex !== -1) { // eslint-disable-line no-negated-condition
+				// Backtrack to the last '*' and try to match more characters
+				templateIndex = starIndex + 1;
+				matchIndex++;
+				searchIndex = matchIndex;
+			} else {
+				return false; // No match
+			}
+		}
+
+		// Handle trailing '*' in template
+		while (templateIndex < template.length && template[templateIndex] === '*') {
+			templateIndex++;
+		}
+
+		return templateIndex === template.length;
+	}
+
+	/**
+	* Disable debug output.
+	*
+	* @return {String} namespaces
+	* @api public
+	*/
+	function disable() {
+		const namespaces = [
+			...createDebug.names,
+			...createDebug.skips.map(namespace => '-' + namespace)
+		].join(',');
+		createDebug.enable('');
+		return namespaces;
+	}
+
+	/**
+	* Returns true if the given mode name is enabled, false otherwise.
+	*
+	* @param {String} name
+	* @return {Boolean}
+	* @api public
+	*/
+	function enabled(name) {
+		for (const skip of createDebug.skips) {
+			if (matchesTemplate(name, skip)) {
+				return false;
+			}
+		}
+
+		for (const ns of createDebug.names) {
+			if (matchesTemplate(name, ns)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	* Coerce `val`.
+	*
+	* @param {Mixed} val
+	* @return {Mixed}
+	* @api private
+	*/
+	function coerce(val) {
+		if (val instanceof Error) {
+			return val.stack || val.message;
+		}
+		return val;
+	}
+
+	/**
+	* XXX DO NOT USE. This is a temporary stub function.
+	* XXX It WILL be removed in the next major release.
+	*/
+	function destroy() {
+		console.warn('Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.');
+	}
+
+	createDebug.enable(createDebug.load());
+
+	return createDebug;
+}
+
+module.exports = setup;
diff --git a/server/node_modules/socks-proxy-agent/node_modules/debug/src/index.js b/server/node_modules/socks-proxy-agent/node_modules/debug/src/index.js
new file mode 100644
index 0000000..bf4c57f
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/debug/src/index.js
@@ -0,0 +1,10 @@
+/**
+ * Detect Electron renderer / nwjs process, which is node, but we should
+ * treat as a browser.
+ */
+
+if (typeof process === 'undefined' || process.type === 'renderer' || process.browser === true || process.__nwjs) {
+	module.exports = require('./browser.js');
+} else {
+	module.exports = require('./node.js');
+}
diff --git a/server/node_modules/socks-proxy-agent/node_modules/debug/src/node.js b/server/node_modules/socks-proxy-agent/node_modules/debug/src/node.js
new file mode 100644
index 0000000..715560a
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/debug/src/node.js
@@ -0,0 +1,263 @@
+/**
+ * Module dependencies.
+ */
+
+const tty = require('tty');
+const util = require('util');
+
+/**
+ * This is the Node.js implementation of `debug()`.
+ */
+
+exports.init = init;
+exports.log = log;
+exports.formatArgs = formatArgs;
+exports.save = save;
+exports.load = load;
+exports.useColors = useColors;
+exports.destroy = util.deprecate(
+	() => {},
+	'Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.'
+);
+
+/**
+ * Colors.
+ */
+
+exports.colors = [6, 2, 3, 4, 5, 1];
+
+try {
+	// Optional dependency (as in, doesn't need to be installed, NOT like optionalDependencies in package.json)
+	// eslint-disable-next-line import/no-extraneous-dependencies
+	const supportsColor = require('supports-color');
+
+	if (supportsColor && (supportsColor.stderr || supportsColor).level >= 2) {
+		exports.colors = [
+			20,
+			21,
+			26,
+			27,
+			32,
+			33,
+			38,
+			39,
+			40,
+			41,
+			42,
+			43,
+			44,
+			45,
+			56,
+			57,
+			62,
+			63,
+			68,
+			69,
+			74,
+			75,
+			76,
+			77,
+			78,
+			79,
+			80,
+			81,
+			92,
+			93,
+			98,
+			99,
+			112,
+			113,
+			128,
+			129,
+			134,
+			135,
+			148,
+			149,
+			160,
+			161,
+			162,
+			163,
+			164,
+			165,
+			166,
+			167,
+			168,
+			169,
+			170,
+			171,
+			172,
+			173,
+			178,
+			179,
+			184,
+			185,
+			196,
+			197,
+			198,
+			199,
+			200,
+			201,
+			202,
+			203,
+			204,
+			205,
+			206,
+			207,
+			208,
+			209,
+			214,
+			215,
+			220,
+			221
+		];
+	}
+} catch (error) {
+	// Swallow - we only care if `supports-color` is available; it doesn't have to be.
+}
+
+/**
+ * Build up the default `inspectOpts` object from the environment variables.
+ *
+ *   $ DEBUG_COLORS=no DEBUG_DEPTH=10 DEBUG_SHOW_HIDDEN=enabled node script.js
+ */
+
+exports.inspectOpts = Object.keys(process.env).filter(key => {
+	return /^debug_/i.test(key);
+}).reduce((obj, key) => {
+	// Camel-case
+	const prop = key
+		.substring(6)
+		.toLowerCase()
+		.replace(/_([a-z])/g, (_, k) => {
+			return k.toUpperCase();
+		});
+
+	// Coerce string value into JS value
+	let val = process.env[key];
+	if (/^(yes|on|true|enabled)$/i.test(val)) {
+		val = true;
+	} else if (/^(no|off|false|disabled)$/i.test(val)) {
+		val = false;
+	} else if (val === 'null') {
+		val = null;
+	} else {
+		val = Number(val);
+	}
+
+	obj[prop] = val;
+	return obj;
+}, {});
+
+/**
+ * Is stdout a TTY? Colored output is enabled when `true`.
+ */
+
+function useColors() {
+	return 'colors' in exports.inspectOpts ?
+		Boolean(exports.inspectOpts.colors) :
+		tty.isatty(process.stderr.fd);
+}
+
+/**
+ * Adds ANSI color escape codes if enabled.
+ *
+ * @api public
+ */
+
+function formatArgs(args) {
+	const {namespace: name, useColors} = this;
+
+	if (useColors) {
+		const c = this.color;
+		const colorCode = '\u001B[3' + (c < 8 ? c : '8;5;' + c);
+		const prefix = `  ${colorCode};1m${name} \u001B[0m`;
+
+		args[0] = prefix + args[0].split('\n').join('\n' + prefix);
+		args.push(colorCode + 'm+' + module.exports.humanize(this.diff) + '\u001B[0m');
+	} else {
+		args[0] = getDate() + name + ' ' + args[0];
+	}
+}
+
+function getDate() {
+	if (exports.inspectOpts.hideDate) {
+		return '';
+	}
+	return new Date().toISOString() + ' ';
+}
+
+/**
+ * Invokes `util.formatWithOptions()` with the specified arguments and writes to stderr.
+ */
+
+function log(...args) {
+	return process.stderr.write(util.formatWithOptions(exports.inspectOpts, ...args) + '\n');
+}
+
+/**
+ * Save `namespaces`.
+ *
+ * @param {String} namespaces
+ * @api private
+ */
+function save(namespaces) {
+	if (namespaces) {
+		process.env.DEBUG = namespaces;
+	} else {
+		// If you set a process.env field to null or undefined, it gets cast to the
+		// string 'null' or 'undefined'. Just delete instead.
+		delete process.env.DEBUG;
+	}
+}
+
+/**
+ * Load `namespaces`.
+ *
+ * @return {String} returns the previously persisted debug modes
+ * @api private
+ */
+
+function load() {
+	return process.env.DEBUG;
+}
+
+/**
+ * Init logic for `debug` instances.
+ *
+ * Create a new `inspectOpts` object in case `useColors` is set
+ * differently for a particular `debug` instance.
+ */
+
+function init(debug) {
+	debug.inspectOpts = {};
+
+	const keys = Object.keys(exports.inspectOpts);
+	for (let i = 0; i < keys.length; i++) {
+		debug.inspectOpts[keys[i]] = exports.inspectOpts[keys[i]];
+	}
+}
+
+module.exports = require('./common')(exports);
+
+const {formatters} = module.exports;
+
+/**
+ * Map %o to `util.inspect()`, all on a single line.
+ */
+
+formatters.o = function (v) {
+	this.inspectOpts.colors = this.useColors;
+	return util.inspect(v, this.inspectOpts)
+		.split('\n')
+		.map(str => str.trim())
+		.join(' ');
+};
+
+/**
+ * Map %O to `util.inspect()`, allowing multiple lines if needed.
+ */
+
+formatters.O = function (v) {
+	this.inspectOpts.colors = this.useColors;
+	return util.inspect(v, this.inspectOpts);
+};
diff --git a/server/node_modules/socks-proxy-agent/node_modules/ms/index.js b/server/node_modules/socks-proxy-agent/node_modules/ms/index.js
new file mode 100644
index 0000000..ea734fb
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/ms/index.js
@@ -0,0 +1,162 @@
+/**
+ * Helpers.
+ */
+
+var s = 1000;
+var m = s * 60;
+var h = m * 60;
+var d = h * 24;
+var w = d * 7;
+var y = d * 365.25;
+
+/**
+ * Parse or format the given `val`.
+ *
+ * Options:
+ *
+ *  - `long` verbose formatting [false]
+ *
+ * @param {String|Number} val
+ * @param {Object} [options]
+ * @throws {Error} throw an error if val is not a non-empty string or a number
+ * @return {String|Number}
+ * @api public
+ */
+
+module.exports = function (val, options) {
+  options = options || {};
+  var type = typeof val;
+  if (type === 'string' && val.length > 0) {
+    return parse(val);
+  } else if (type === 'number' && isFinite(val)) {
+    return options.long ? fmtLong(val) : fmtShort(val);
+  }
+  throw new Error(
+    'val is not a non-empty string or a valid number. val=' +
+      JSON.stringify(val)
+  );
+};
+
+/**
+ * Parse the given `str` and return milliseconds.
+ *
+ * @param {String} str
+ * @return {Number}
+ * @api private
+ */
+
+function parse(str) {
+  str = String(str);
+  if (str.length > 100) {
+    return;
+  }
+  var match = /^(-?(?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|weeks?|w|years?|yrs?|y)?$/i.exec(
+    str
+  );
+  if (!match) {
+    return;
+  }
+  var n = parseFloat(match[1]);
+  var type = (match[2] || 'ms').toLowerCase();
+  switch (type) {
+    case 'years':
+    case 'year':
+    case 'yrs':
+    case 'yr':
+    case 'y':
+      return n * y;
+    case 'weeks':
+    case 'week':
+    case 'w':
+      return n * w;
+    case 'days':
+    case 'day':
+    case 'd':
+      return n * d;
+    case 'hours':
+    case 'hour':
+    case 'hrs':
+    case 'hr':
+    case 'h':
+      return n * h;
+    case 'minutes':
+    case 'minute':
+    case 'mins':
+    case 'min':
+    case 'm':
+      return n * m;
+    case 'seconds':
+    case 'second':
+    case 'secs':
+    case 'sec':
+    case 's':
+      return n * s;
+    case 'milliseconds':
+    case 'millisecond':
+    case 'msecs':
+    case 'msec':
+    case 'ms':
+      return n;
+    default:
+      return undefined;
+  }
+}
+
+/**
+ * Short format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtShort(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return Math.round(ms / d) + 'd';
+  }
+  if (msAbs >= h) {
+    return Math.round(ms / h) + 'h';
+  }
+  if (msAbs >= m) {
+    return Math.round(ms / m) + 'm';
+  }
+  if (msAbs >= s) {
+    return Math.round(ms / s) + 's';
+  }
+  return ms + 'ms';
+}
+
+/**
+ * Long format for `ms`.
+ *
+ * @param {Number} ms
+ * @return {String}
+ * @api private
+ */
+
+function fmtLong(ms) {
+  var msAbs = Math.abs(ms);
+  if (msAbs >= d) {
+    return plural(ms, msAbs, d, 'day');
+  }
+  if (msAbs >= h) {
+    return plural(ms, msAbs, h, 'hour');
+  }
+  if (msAbs >= m) {
+    return plural(ms, msAbs, m, 'minute');
+  }
+  if (msAbs >= s) {
+    return plural(ms, msAbs, s, 'second');
+  }
+  return ms + ' ms';
+}
+
+/**
+ * Pluralization helper.
+ */
+
+function plural(ms, msAbs, n, name) {
+  var isPlural = msAbs >= n * 1.5;
+  return Math.round(ms / n) + ' ' + name + (isPlural ? 's' : '');
+}
diff --git a/server/node_modules/socks-proxy-agent/node_modules/ms/license.md b/server/node_modules/socks-proxy-agent/node_modules/ms/license.md
new file mode 100644
index 0000000..fa5d39b
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/ms/license.md
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2020 Vercel, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/socks-proxy-agent/node_modules/ms/package.json b/server/node_modules/socks-proxy-agent/node_modules/ms/package.json
new file mode 100644
index 0000000..4997189
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/ms/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "ms",
+  "version": "2.1.3",
+  "description": "Tiny millisecond conversion utility",
+  "repository": "vercel/ms",
+  "main": "./index",
+  "files": [
+    "index.js"
+  ],
+  "scripts": {
+    "precommit": "lint-staged",
+    "lint": "eslint lib/* bin/*",
+    "test": "mocha tests.js"
+  },
+  "eslintConfig": {
+    "extends": "eslint:recommended",
+    "env": {
+      "node": true,
+      "es6": true
+    }
+  },
+  "lint-staged": {
+    "*.js": [
+      "npm run lint",
+      "prettier --single-quote --write",
+      "git add"
+    ]
+  },
+  "license": "MIT",
+  "devDependencies": {
+    "eslint": "4.18.2",
+    "expect.js": "0.3.1",
+    "husky": "0.14.3",
+    "lint-staged": "5.0.0",
+    "mocha": "4.0.1",
+    "prettier": "2.0.5"
+  }
+}
diff --git a/server/node_modules/socks-proxy-agent/node_modules/ms/readme.md b/server/node_modules/socks-proxy-agent/node_modules/ms/readme.md
new file mode 100644
index 0000000..0fc1abb
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/node_modules/ms/readme.md
@@ -0,0 +1,59 @@
+# ms
+
+![CI](https://github.com/vercel/ms/workflows/CI/badge.svg)
+
+Use this package to easily convert various time formats to milliseconds.
+
+## Examples
+
+```js
+ms('2 days')  // 172800000
+ms('1d')      // 86400000
+ms('10h')     // 36000000
+ms('2.5 hrs') // 9000000
+ms('2h')      // 7200000
+ms('1m')      // 60000
+ms('5s')      // 5000
+ms('1y')      // 31557600000
+ms('100')     // 100
+ms('-3 days') // -259200000
+ms('-1h')     // -3600000
+ms('-200')    // -200
+```
+
+### Convert from Milliseconds
+
+```js
+ms(60000)             // "1m"
+ms(2 * 60000)         // "2m"
+ms(-3 * 60000)        // "-3m"
+ms(ms('10 hours'))    // "10h"
+```
+
+### Time Format Written-Out
+
+```js
+ms(60000, { long: true })             // "1 minute"
+ms(2 * 60000, { long: true })         // "2 minutes"
+ms(-3 * 60000, { long: true })        // "-3 minutes"
+ms(ms('10 hours'), { long: true })    // "10 hours"
+```
+
+## Features
+
+- Works both in [Node.js](https://nodejs.org) and in the browser
+- If a number is supplied to `ms`, a string with a unit is returned
+- If a string that contains the number is supplied, it returns it as a number (e.g.: it returns `100` for `'100'`)
+- If you pass a string with a number and a valid unit, the number of equivalent milliseconds is returned
+
+## Related Packages
+
+- [ms.macro](https://github.com/knpwrs/ms.macro) - Run `ms` as a macro at build-time.
+
+## Caught a Bug?
+
+1. [Fork](https://help.github.com/articles/fork-a-repo/) this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device
+2. Link the package to the global module directory: `npm link`
+3. Within the module you want to test your local development instance of ms, just link it to the dependencies: `npm link ms`. Instead of the default one from npm, Node.js will now use your clone of ms!
+
+As always, you can run the tests using: `npm test`
diff --git a/server/node_modules/socks-proxy-agent/package.json b/server/node_modules/socks-proxy-agent/package.json
new file mode 100644
index 0000000..e9b655a
--- /dev/null
+++ b/server/node_modules/socks-proxy-agent/package.json
@@ -0,0 +1,181 @@
+{
+  "name": "socks-proxy-agent",
+  "description": "A SOCKS proxy `http.Agent` implementation for HTTP and HTTPS",
+  "homepage": "https://github.com/TooTallNate/node-socks-proxy-agent#readme",
+  "version": "6.2.1",
+  "main": "dist/index.js",
+  "author": {
+    "email": "nathan@tootallnate.net",
+    "name": "Nathan Rajlich",
+    "url": "http://n8.io/"
+  },
+  "contributors": [
+    {
+      "name": "Kiko Beats",
+      "email": "josefrancisco.verdu@gmail.com"
+    },
+    {
+      "name": "Josh Glazebrook",
+      "email": "josh@joshglazebrook.com"
+    },
+    {
+      "name": "talmobi",
+      "email": "talmobi@users.noreply.github.com"
+    },
+    {
+      "name": "Indospace.io",
+      "email": "justin@indospace.io"
+    },
+    {
+      "name": "Kilian von Pflugk",
+      "email": "github@jumoog.io"
+    },
+    {
+      "name": "Kyle",
+      "email": "admin@hk1229.cn"
+    },
+    {
+      "name": "Matheus Fernandes",
+      "email": "matheus.frndes@gmail.com"
+    },
+    {
+      "name": "Ricky Miller",
+      "email": "richardkazuomiller@gmail.com"
+    },
+    {
+      "name": "Shantanu Sharma",
+      "email": "shantanu34@outlook.com"
+    },
+    {
+      "name": "Tim Perry",
+      "email": "pimterry@gmail.com"
+    },
+    {
+      "name": "Vadim Baryshev",
+      "email": "vadimbaryshev@gmail.com"
+    },
+    {
+      "name": "jigu",
+      "email": "luo1257857309@gmail.com"
+    },
+    {
+      "name": "Alba Mendez",
+      "email": "me@jmendeth.com"
+    },
+    {
+      "name": "Дмитрий Гуденков",
+      "email": "Dimangud@rambler.ru"
+    },
+    {
+      "name": "Andrei Bitca",
+      "email": "63638922+andrei-bitca-dc@users.noreply.github.com"
+    },
+    {
+      "name": "Andrew Casey",
+      "email": "amcasey@users.noreply.github.com"
+    },
+    {
+      "name": "Brandon Ros",
+      "email": "brandonros1@gmail.com"
+    },
+    {
+      "name": "Dang Duy Thanh",
+      "email": "thanhdd.it@gmail.com"
+    },
+    {
+      "name": "Dimitar Nestorov",
+      "email": "8790386+dimitarnestorov@users.noreply.github.com"
+    }
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/TooTallNate/node-socks-proxy-agent.git"
+  },
+  "bugs": {
+    "url": "https://github.com/TooTallNate/node-socks-proxy-agent/issues"
+  },
+  "keywords": [
+    "agent",
+    "http",
+    "https",
+    "proxy",
+    "socks",
+    "socks4",
+    "socks4a",
+    "socks5",
+    "socks5h"
+  ],
+  "dependencies": {
+    "agent-base": "^6.0.2",
+    "debug": "^4.3.3",
+    "socks": "^2.6.2"
+  },
+  "devDependencies": {
+    "@commitlint/cli": "latest",
+    "@commitlint/config-conventional": "latest",
+    "@types/debug": "latest",
+    "@types/node": "latest",
+    "cacheable-lookup": "^6.0.4",
+    "conventional-github-releaser": "latest",
+    "dns2": "latest",
+    "finepack": "latest",
+    "git-authors-cli": "latest",
+    "mocha": "9",
+    "nano-staged": "latest",
+    "npm-check-updates": "latest",
+    "prettier-standard": "latest",
+    "raw-body": "latest",
+    "rimraf": "latest",
+    "simple-git-hooks": "latest",
+    "socksv5": "github:TooTallNate/socksv5#fix/dstSock-close-event",
+    "standard": "latest",
+    "standard-markdown": "latest",
+    "standard-version": "latest",
+    "ts-standard": "latest",
+    "typescript": "latest"
+  },
+  "engines": {
+    "node": ">= 10"
+  },
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "build": "tsc",
+    "clean": "rimraf node_modules",
+    "contributors": "(git-authors-cli && finepack && git add package.json && git commit -m 'build: contributors' --no-verify) || true",
+    "lint": "ts-standard",
+    "postrelease": "npm run release:tags && npm run release:github && (ci-publish || npm publish --access=public)",
+    "prebuild": "rimraf dist",
+    "prepublishOnly": "npm run build",
+    "prerelease": "npm run update:check && npm run contributors",
+    "release": "standard-version -a",
+    "release:github": "conventional-github-releaser -p angular",
+    "release:tags": "git push --follow-tags origin HEAD:master",
+    "test": "mocha --reporter spec",
+    "update": "ncu -u",
+    "update:check": "ncu -- --error-level 2"
+  },
+  "license": "MIT",
+  "commitlint": {
+    "extends": [
+      "@commitlint/config-conventional"
+    ]
+  },
+  "nano-staged": {
+    "*.js": [
+      "prettier-standard"
+    ],
+    "*.md": [
+      "standard-markdown"
+    ],
+    "package.json": [
+      "finepack"
+    ]
+  },
+  "simple-git-hooks": {
+    "commit-msg": "npx commitlint --edit",
+    "pre-commit": "npx nano-staged"
+  },
+  "typings": "dist/index.d.ts"
+}
diff --git a/server/node_modules/socks/.eslintrc.cjs b/server/node_modules/socks/.eslintrc.cjs
new file mode 100644
index 0000000..cc5d089
--- /dev/null
+++ b/server/node_modules/socks/.eslintrc.cjs
@@ -0,0 +1,11 @@
+module.exports = {
+  root: true,
+  parser: '@typescript-eslint/parser',
+  plugins: [
+    '@typescript-eslint',
+  ],
+  extends: [
+    'eslint:recommended',
+    'plugin:@typescript-eslint/recommended',
+  ],
+};
\ No newline at end of file
diff --git a/server/node_modules/socks/.prettierrc.yaml b/server/node_modules/socks/.prettierrc.yaml
new file mode 100644
index 0000000..d7b7335
--- /dev/null
+++ b/server/node_modules/socks/.prettierrc.yaml
@@ -0,0 +1,7 @@
+parser: typescript
+printWidth: 80
+tabWidth: 2
+singleQuote: true
+trailingComma: all
+arrowParens: always
+bracketSpacing: false
\ No newline at end of file
diff --git a/server/node_modules/socks/LICENSE b/server/node_modules/socks/LICENSE
new file mode 100644
index 0000000..b2442a9
--- /dev/null
+++ b/server/node_modules/socks/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2013 Josh Glazebrook
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/socks/README.md b/server/node_modules/socks/README.md
new file mode 100644
index 0000000..4045852
--- /dev/null
+++ b/server/node_modules/socks/README.md
@@ -0,0 +1,686 @@
+# socks  [![Build Status](https://travis-ci.org/JoshGlazebrook/socks.svg?branch=master)](https://travis-ci.org/JoshGlazebrook/socks)  [![Coverage Status](https://coveralls.io/repos/github/JoshGlazebrook/socks/badge.svg?branch=master)](https://coveralls.io/github/JoshGlazebrook/socks?branch=v2)
+
+Fully featured SOCKS proxy client supporting SOCKSv4, SOCKSv4a, and SOCKSv5. Includes Bind and Associate functionality.
+
+> Looking for Node.js agent? Check [node-socks-proxy-agent](https://github.com/TooTallNate/node-socks-proxy-agent).
+
+### Features
+
+* Supports SOCKS v4, v4a, v5, and v5h protocols.
+* Supports the CONNECT, BIND, and ASSOCIATE commands.
+* Supports callbacks, promises, and events for proxy connection creation async flow control.
+* Supports proxy chaining (CONNECT only).
+* Supports user/password authentication.
+* Supports custom authentication.
+* Built in UDP frame creation & parse functions.
+* Created with TypeScript, type definitions are provided.
+
+### Requirements
+
+* Node.js v10.0+  (Please use [v1](https://github.com/JoshGlazebrook/socks/tree/82d83923ad960693d8b774cafe17443ded7ed584) for older versions of Node.js)
+
+### Looking for v1?
+* Docs for v1 are available [here](https://github.com/JoshGlazebrook/socks/tree/82d83923ad960693d8b774cafe17443ded7ed584)
+
+## Installation
+
+`yarn add socks`
+
+or
+
+`npm install --save socks`
+
+## Usage
+
+```typescript
+// TypeScript
+import { SocksClient, SocksClientOptions, SocksClientChainOptions } from 'socks';
+
+// ES6 JavaScript
+import { SocksClient } from 'socks';
+
+// Legacy JavaScript
+const SocksClient = require('socks').SocksClient;
+```
+
+## Quick Start Example
+
+Connect to github.com (192.30.253.113) on port 80, using a SOCKS proxy.
+
+```javascript
+const options = {
+  proxy: {
+    host: '159.203.75.200', // ipv4 or ipv6 or hostname
+    port: 1080,
+    type: 5 // Proxy version (4 or 5)
+  },
+
+  command: 'connect', // SOCKS command (createConnection factory function only supports the connect command)
+
+  destination: {
+    host: '192.30.253.113', // github.com (hostname lookups are supported with SOCKS v4a and 5)
+    port: 80
+  }
+};
+
+// Async/Await
+try {
+  const info = await SocksClient.createConnection(options);
+
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy server)
+} catch (err) {
+  // Handle errors
+}
+
+// Promises
+SocksClient.createConnection(options)
+.then(info => {
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy server)
+})
+.catch(err => {
+  // Handle errors
+});
+
+// Callbacks
+SocksClient.createConnection(options, (err, info) => {
+  if (!err) {
+    console.log(info.socket);
+    // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy server)
+  } else {
+    // Handle errors
+  }
+});
+```
+
+## Chaining Proxies
+
+**Note:** Chaining is only supported when using the SOCKS connect command, and chaining can only be done through the special factory chaining function.
+
+This example makes a proxy chain through two SOCKS proxies to ip-api.com. Once the connection to the destination is established it sends an HTTP request to get a JSON response that returns ip info for the requesting ip.
+
+```javascript
+const options = {
+  destination: {
+    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
+    port: 80
+  },
+  command: 'connect', // Only the connect command is supported when chaining proxies.
+  proxies: [ // The chain order is the order in the proxies array, meaning the last proxy will establish a connection to the destination.
+    {
+      host: '159.203.75.235', // ipv4, ipv6, or hostname
+      port: 1081,
+      type: 5
+    },
+    {
+      host: '104.131.124.203', // ipv4, ipv6, or hostname
+      port: 1081,
+      type: 5
+    }
+  ]
+}
+
+// Async/Await
+try {
+  const info = await SocksClient.createConnectionChain(options);
+
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+
+  console.log(info.socket.remoteAddress) // The remote address of the returned socket is the first proxy in the chain.
+  // 159.203.75.235
+
+  info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+  info.socket.on('data', (data) => {
+    console.log(data.toString()); // ip-api.com sees that the last proxy in the chain (104.131.124.203) is connected to it.
+    /*
+      HTTP/1.1 200 OK
+      Access-Control-Allow-Origin: *
+      Content-Type: application/json; charset=utf-8
+      Date: Sun, 24 Dec 2017 03:47:51 GMT
+      Content-Length: 300
+
+      {
+        "as":"AS14061 Digital Ocean, Inc.",
+        "city":"Clifton",
+        "country":"United States",
+        "countryCode":"US",
+        "isp":"Digital Ocean",
+        "lat":40.8326,
+        "lon":-74.1307,
+        "org":"Digital Ocean",
+        "query":"104.131.124.203",
+        "region":"NJ",
+        "regionName":"New Jersey",
+        "status":"success",
+        "timezone":"America/New_York",
+        "zip":"07014"
+      }
+    */
+  });
+} catch (err) {
+  // Handle errors
+}
+
+// Promises
+SocksClient.createConnectionChain(options)
+.then(info => {
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy server)
+
+  console.log(info.socket.remoteAddress) // The remote address of the returned socket is the first proxy in the chain.
+  // 159.203.75.235
+
+  info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+  info.socket.on('data', (data) => {
+    console.log(data.toString()); // ip-api.com sees that the last proxy in the chain (104.131.124.203) is connected to it.
+    /*
+      HTTP/1.1 200 OK
+      Access-Control-Allow-Origin: *
+      Content-Type: application/json; charset=utf-8
+      Date: Sun, 24 Dec 2017 03:47:51 GMT
+      Content-Length: 300
+
+      {
+        "as":"AS14061 Digital Ocean, Inc.",
+        "city":"Clifton",
+        "country":"United States",
+        "countryCode":"US",
+        "isp":"Digital Ocean",
+        "lat":40.8326,
+        "lon":-74.1307,
+        "org":"Digital Ocean",
+        "query":"104.131.124.203",
+        "region":"NJ",
+        "regionName":"New Jersey",
+        "status":"success",
+        "timezone":"America/New_York",
+        "zip":"07014"
+      }
+    */
+  });
+})
+.catch(err => {
+  // Handle errors
+});
+
+// Callbacks
+SocksClient.createConnectionChain(options, (err, info) => {
+  if (!err) {
+    console.log(info.socket);
+    // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy server)
+
+    console.log(info.socket.remoteAddress) // The remote address of the returned socket is the first proxy in the chain.
+  // 159.203.75.235
+
+  info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+  info.socket.on('data', (data) => {
+    console.log(data.toString()); // ip-api.com sees that the last proxy in the chain (104.131.124.203) is connected to it.
+    /*
+      HTTP/1.1 200 OK
+      Access-Control-Allow-Origin: *
+      Content-Type: application/json; charset=utf-8
+      Date: Sun, 24 Dec 2017 03:47:51 GMT
+      Content-Length: 300
+
+      {
+        "as":"AS14061 Digital Ocean, Inc.",
+        "city":"Clifton",
+        "country":"United States",
+        "countryCode":"US",
+        "isp":"Digital Ocean",
+        "lat":40.8326,
+        "lon":-74.1307,
+        "org":"Digital Ocean",
+        "query":"104.131.124.203",
+        "region":"NJ",
+        "regionName":"New Jersey",
+        "status":"success",
+        "timezone":"America/New_York",
+        "zip":"07014"
+      }
+    */
+  });
+  } else {
+    // Handle errors
+  }
+});
+```
+
+## Bind Example (TCP Relay)
+
+When the bind command is sent to a SOCKS v4/v5 proxy server, the proxy server starts listening on a new TCP port and the proxy relays then remote host information back to the client. When another remote client connects to the proxy server on this port the SOCKS proxy sends a notification that an incoming connection has been accepted to the initial client and a full duplex stream is now established to the initial client and the client that connected to that special port.
+
+```javascript
+const options = {
+  proxy: {
+    host: '159.203.75.235', // ipv4, ipv6, or hostname
+    port: 1081,
+    type: 5
+  },
+
+  command: 'bind',
+
+  // When using BIND, the destination should be the remote client that is expected to connect to the SOCKS proxy. Using 0.0.0.0 makes the Proxy accept any incoming connection on that port.
+  destination: {
+    host: '0.0.0.0',
+    port: 0
+  }
+};
+
+// Creates a new SocksClient instance.
+const client = new SocksClient(options);
+
+// When the SOCKS proxy has bound a new port and started listening, this event is fired.
+client.on('bound', info => {
+  console.log(info.remoteHost);
+  /*
+  {
+    host: "159.203.75.235",
+    port: 57362
+  }
+  */
+});
+
+// When a client connects to the newly bound port on the SOCKS proxy, this event is fired.
+client.on('established', info => {
+  // info.remoteHost is the remote address of the client that connected to the SOCKS proxy.
+  console.log(info.remoteHost);
+  /*
+    host: 67.171.34.23,
+    port: 49823
+  */
+
+  console.log(info.socket);
+  // <Socket ...>  (This is a raw net.Socket that is a connection between the initial client and the remote client that connected to the proxy)
+
+  // Handle received data...
+  info.socket.on('data', data => {
+    console.log('recv', data);
+  });
+});
+
+// An error occurred trying to establish this SOCKS connection.
+client.on('error', err => {
+  console.error(err);
+});
+
+// Start connection to proxy
+client.connect();
+```
+
+## Associate Example (UDP Relay)
+
+When the associate command is sent to a SOCKS v5 proxy server, it sets up a UDP relay that allows the client to send UDP packets to a remote host through the proxy server, and also receive UDP packet responses back through the proxy server.
+
+```javascript
+const options = {
+  proxy: {
+    host: '159.203.75.235', // ipv4, ipv6, or hostname
+    port: 1081,
+    type: 5
+  },
+
+  command: 'associate',
+
+  // When using associate, the destination should be the remote client that is expected to send UDP packets to the proxy server to be forwarded. This should be your local ip, or optionally the wildcard address (0.0.0.0)  UDP Client <-> Proxy <-> UDP Client
+  destination: {
+    host: '0.0.0.0',
+    port: 0
+  }
+};
+
+// Create a local UDP socket for sending packets to the proxy.
+const udpSocket = dgram.createSocket('udp4');
+udpSocket.bind();
+
+// Listen for incoming UDP packets from the proxy server.
+udpSocket.on('message', (message, rinfo) => {
+  console.log(SocksClient.parseUDPFrame(message));
+  /*
+  { frameNumber: 0,
+    remoteHost: { host: '165.227.108.231', port: 4444 }, // The remote host that replied with a UDP packet
+    data: <Buffer 74 65 73 74 0a> // The data
+  }
+  */
+});
+
+let client = new SocksClient(options);
+
+// When the UDP relay is established, this event is fired and includes the UDP relay port to send data to on the proxy server.
+client.on('established', info => {
+  console.log(info.remoteHost);
+  /*
+    {
+      host: '159.203.75.235',
+      port: 44711
+    }
+  */
+
+  // Send 'hello' to 165.227.108.231:4444
+  const packet = SocksClient.createUDPFrame({
+    remoteHost: { host: '165.227.108.231', port: 4444 },
+    data: Buffer.from('hello')
+  });
+  udpSocket.send(packet, info.remoteHost.port, info.remoteHost.host);
+});
+
+// Start connection
+client.connect();
+```
+
+**Note:** The associate TCP connection to the proxy must remain open for the UDP relay to work.
+
+## Additional Examples
+
+[Documentation](docs/index.md)
+
+
+## Migrating from v1
+
+Looking for a guide to migrate from v1? Look [here](docs/migratingFromV1.md)
+
+## Api Reference:
+
+**Note:** socks includes full TypeScript definitions. These can even be used without using TypeScript as most IDEs (such as VS Code) will use these type definition files for auto completion intellisense even in JavaScript files.
+
+* Class: SocksClient
+  * [new SocksClient(options[, callback])](#new-socksclientoptions)
+  * [Class Method: SocksClient.createConnection(options[, callback])](#class-method-socksclientcreateconnectionoptions-callback)
+  * [Class Method: SocksClient.createConnectionChain(options[, callback])](#class-method-socksclientcreateconnectionchainoptions-callback)
+  * [Class Method: SocksClient.createUDPFrame(options)](#class-method-socksclientcreateudpframedetails)
+  * [Class Method: SocksClient.parseUDPFrame(data)](#class-method-socksclientparseudpframedata)
+  * [Event: 'error'](#event-error)
+  * [Event: 'bound'](#event-bound)
+  * [Event: 'established'](#event-established)
+  * [client.connect()](#clientconnect)
+  * [client.socksClientOptions](#clientconnect)
+
+### SocksClient
+
+SocksClient establishes SOCKS proxy connections to remote destination hosts. These proxy connections are fully transparent to the server and once established act as full duplex streams. SOCKS v4, v4a, v5, and v5h are supported, as well as the connect, bind, and associate commands.
+
+SocksClient supports creating connections using callbacks, promises, and async/await flow control using two static factory functions createConnection and createConnectionChain. It also internally extends EventEmitter which results in allowing event handling based async flow control.
+
+**SOCKS Compatibility Table**
+
+Note: When using 4a please specify type: 4, and when using 5h please specify type 5.
+
+| Socks Version | TCP | UDP | IPv4 | IPv6 | Hostname |
+| --- | :---: | :---: | :---: | :---: | :---: |
+| SOCKS v4 | ✅ | ❌ | ✅ | ❌ | ❌ |
+| SOCKS v4a | ✅ | ❌ | ✅ | ❌ | ✅ |
+| SOCKS v5 (includes v5h) | ✅ | ✅ | ✅ | ✅ | ✅ |
+
+### new SocksClient(options)
+
+* ```options``` {SocksClientOptions} - An object describing the SOCKS proxy to use, the command to send and establish, and the destination host to connect to.
+
+### SocksClientOptions
+
+```typescript
+{
+  proxy: {
+    host: '159.203.75.200', // ipv4, ipv6, or hostname
+    port: 1080,
+    type: 5, // Proxy version (4 or 5). For v4a use 4, for v5h use 5.
+
+    // Optional fields
+    userId: 'some username', // Used for SOCKS4 userId auth, and SOCKS5 user/pass auth in conjunction with password.
+    password: 'some password', // Used in conjunction with userId for user/pass auth for SOCKS5 proxies.
+    custom_auth_method: 0x80,  // If using a custom auth method, specify the type here. If this is set, ALL other custom_auth_*** options must be set as well.
+    custom_auth_request_handler: async () =>. {
+      // This will be called when it's time to send the custom auth handshake. You must return a Buffer containing the data to send as your authentication.
+      return Buffer.from([0x01,0x02,0x03]);
+    },
+    // This is the expected size (bytes) of the custom auth response from the proxy server.
+    custom_auth_response_size: 2,
+    // This is called when the auth response is received. The received packet is passed in as a Buffer, and you must return a boolean indicating the response from the server said your custom auth was successful or failed.
+    custom_auth_response_handler: async (data) => {
+      return data[1] === 0x00;
+    }
+  },
+
+  command: 'connect', // connect, bind, associate
+
+  destination: {
+    host: '192.30.253.113', // ipv4, ipv6, hostname. Hostnames work with v4a and v5.
+    port: 80
+  },
+
+  // Optional fields
+  timeout: 30000, // How long to wait to establish a proxy connection. (defaults to 30 seconds)
+
+  set_tcp_nodelay: true // If true, will turn on the underlying sockets TCP_NODELAY option.
+}
+```
+
+### Class Method: SocksClient.createConnection(options[, callback])
+* ```options``` { SocksClientOptions } - An object describing the SOCKS proxy to use, the command to send and establish, and the destination host to connect to.
+* ```callback``` { Function } - Optional callback function that is called when the proxy connection is established, or an error occurs.
+* ```returns``` { Promise } - A Promise is returned that is resolved when the proxy connection is established, or rejected when an error occurs.
+
+Creates a new proxy connection through the given proxy to the given destination host. This factory function supports callbacks and promises for async flow control.
+
+**Note:** If a callback function is provided, the promise will always resolve regardless of an error occurring. Please be sure to exclusively use either promises or callbacks when using this factory function.
+
+```typescript
+const options = {
+  proxy: {
+    host: '159.203.75.200', // ipv4, ipv6, or hostname
+    port: 1080,
+    type: 5 // Proxy version (4 or 5)
+  },
+
+  command: 'connect', // connect, bind, associate
+
+  destination: {
+    host: '192.30.253.113', // ipv4, ipv6, or hostname
+    port: 80
+  }
+}
+
+// Await/Async (uses a Promise)
+try {
+  const info = await SocksClient.createConnection(options);
+  console.log(info);
+  /*
+  {
+    socket: <Socket ...>,  // Raw net.Socket
+  }
+  */
+  / <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy server)
+
+} catch (err) {
+  // Handle error...
+}
+
+// Promise
+SocksClient.createConnection(options)
+.then(info => {
+  console.log(info);
+  /*
+  {
+    socket: <Socket ...>,  // Raw net.Socket
+  }
+  */
+})
+.catch(err => {
+  // Handle error...
+});
+
+// Callback
+SocksClient.createConnection(options, (err, info) => {
+  if (!err) {
+    console.log(info);
+  /*
+  {
+    socket: <Socket ...>,  // Raw net.Socket
+  }
+  */
+  } else {
+    // Handle error...
+  }
+});
+```
+
+### Class Method: SocksClient.createConnectionChain(options[, callback])
+* ```options``` { SocksClientChainOptions } - An object describing a list of SOCKS proxies to use, the command to send and establish, and the destination host to connect to.
+* ```callback``` { Function } - Optional callback function that is called when the proxy connection chain is established, or an error occurs.
+* ```returns``` { Promise } - A Promise is returned that is resolved when the proxy connection chain is established, or rejected when an error occurs.
+
+Creates a new proxy connection chain through a list of at least two SOCKS proxies to the given destination host. This factory method supports callbacks and promises for async flow control.
+
+**Note:** If a callback function is provided, the promise will always resolve regardless of an error occurring. Please be sure to exclusively use either promises or callbacks when using this factory function.
+
+**Note:** At least two proxies must be provided for the chain to be established.
+
+```typescript
+const options = {
+  proxies: [ // The chain order is the order in the proxies array, meaning the last proxy will establish a connection to the destination.
+    {
+      host: '159.203.75.235', // ipv4, ipv6, or hostname
+      port: 1081,
+      type: 5
+    },
+    {
+      host: '104.131.124.203', // ipv4, ipv6, or hostname
+      port: 1081,
+      type: 5
+    }
+  ]
+
+  command: 'connect', // Only connect is supported in chaining mode.
+
+  destination: {
+    host: '192.30.253.113', // ipv4, ipv6, hostname
+    port: 80
+  }
+}
+```
+
+### Class Method: SocksClient.createUDPFrame(details)
+* ```details``` { SocksUDPFrameDetails } - An object containing the remote host, frame number, and frame data to use when creating a SOCKS UDP frame packet.
+* ```returns``` { Buffer } - A Buffer containing all of the UDP frame data.
+
+Creates a SOCKS UDP frame relay packet that is sent and received via a SOCKS proxy when using the associate command for UDP packet forwarding.
+
+**SocksUDPFrameDetails**
+
+```typescript
+{
+  frameNumber: 0, // The frame number (used for breaking up larger packets)
+
+  remoteHost: { // The remote host to have the proxy send data to, or the remote host that send this data.
+    host: '1.2.3.4',
+    port: 1234
+  },
+
+  data: <Buffer 01 02 03 04...> // A Buffer instance of data to include in the packet (actual data sent to the remote host)
+}
+interface SocksUDPFrameDetails {
+  // The frame number of the packet.
+  frameNumber?: number;
+
+  // The remote host.
+  remoteHost: SocksRemoteHost;
+
+  // The packet data.
+  data: Buffer;
+}
+```
+
+### Class Method: SocksClient.parseUDPFrame(data)
+* ```data``` { Buffer } - A Buffer instance containing SOCKS UDP frame data to parse.
+* ```returns``` { SocksUDPFrameDetails } - An object containing the remote host, frame number, and frame data of the SOCKS UDP frame.
+
+```typescript
+const frame = SocksClient.parseUDPFrame(data);
+console.log(frame);
+/*
+{
+  frameNumber: 0,
+  remoteHost: {
+    host: '1.2.3.4',
+    port: 1234
+  },
+  data: <Buffer 01 02 03 04 ...>
+}
+*/
+```
+
+Parses a Buffer instance and returns the parsed SocksUDPFrameDetails object.
+
+## Event: 'error'
+* ```err``` { SocksClientError } - An Error object containing an error message and the original SocksClientOptions.
+
+This event is emitted if an error occurs when trying to establish the proxy connection.
+
+## Event: 'bound'
+* ```info``` { SocksClientBoundEvent } An object containing a Socket and SocksRemoteHost info.
+
+This event is emitted when using the BIND command on a remote SOCKS proxy server. This event indicates the proxy server is now listening for incoming connections on a specified port.
+
+**SocksClientBoundEvent**
+```typescript
+{
+  socket: net.Socket, // The underlying raw Socket
+  remoteHost: {
+    host: '1.2.3.4', // The remote host that is listening (usually the proxy itself)
+    port: 4444 // The remote port the proxy is listening on for incoming connections (when using BIND).
+  }
+}
+```
+
+## Event: 'established'
+* ```info``` { SocksClientEstablishedEvent } An object containing a Socket and SocksRemoteHost info.
+
+This event is emitted when the following conditions are met:
+1. When using the CONNECT command, and a proxy connection has been established to the remote host.
+2. When using the BIND command, and an incoming connection has been accepted by the proxy and a TCP relay has been established.
+3. When using the ASSOCIATE command, and a UDP relay has been established.
+
+When using BIND, 'bound' is first emitted to indicate the SOCKS server is waiting for an incoming connection, and provides the remote port the SOCKS server is listening on.
+
+When using ASSOCIATE, 'established' is emitted with the remote UDP port the SOCKS server is accepting UDP frame packets on.
+
+**SocksClientEstablishedEvent**
+```typescript
+{
+  socket: net.Socket, // The underlying raw Socket
+  remoteHost: {
+    host: '1.2.3.4', // The remote host that is listening (usually the proxy itself)
+    port: 52738 // The remote port the proxy is listening on for incoming connections (when using BIND).
+  }
+}
+```
+
+## client.connect()
+
+Starts connecting to the remote SOCKS proxy server to establish a proxy connection to the destination host.
+
+## client.socksClientOptions
+* ```returns``` { SocksClientOptions } The options that were passed to the SocksClient.
+
+Gets the options that were passed to the SocksClient when it was created.
+
+
+**SocksClientError**
+```typescript
+{ // Subclassed from Error.
+  message: 'An error has occurred',
+  options: {
+    // SocksClientOptions
+  }
+}
+```
+
+# Further Reading:
+
+Please read the SOCKS 5 specifications for more information on how to use BIND and Associate.
+http://www.ietf.org/rfc/rfc1928.txt
+
+# License
+
+This work is licensed under the [MIT license](http://en.wikipedia.org/wiki/MIT_License).
diff --git a/server/node_modules/socks/build/client/socksclient.js b/server/node_modules/socks/build/client/socksclient.js
new file mode 100644
index 0000000..09b1f55
--- /dev/null
+++ b/server/node_modules/socks/build/client/socksclient.js
@@ -0,0 +1,793 @@
+"use strict";
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.SocksClientError = exports.SocksClient = void 0;
+const events_1 = require("events");
+const net = require("net");
+const smart_buffer_1 = require("smart-buffer");
+const constants_1 = require("../common/constants");
+const helpers_1 = require("../common/helpers");
+const receivebuffer_1 = require("../common/receivebuffer");
+const util_1 = require("../common/util");
+Object.defineProperty(exports, "SocksClientError", { enumerable: true, get: function () { return util_1.SocksClientError; } });
+const ip_address_1 = require("ip-address");
+class SocksClient extends events_1.EventEmitter {
+    constructor(options) {
+        super();
+        this.options = Object.assign({}, options);
+        // Validate SocksClientOptions
+        (0, helpers_1.validateSocksClientOptions)(options);
+        // Default state
+        this.setState(constants_1.SocksClientState.Created);
+    }
+    /**
+     * Creates a new SOCKS connection.
+     *
+     * Note: Supports callbacks and promises. Only supports the connect command.
+     * @param options { SocksClientOptions } Options.
+     * @param callback { Function } An optional callback function.
+     * @returns { Promise }
+     */
+    static createConnection(options, callback) {
+        return new Promise((resolve, reject) => {
+            // Validate SocksClientOptions
+            try {
+                (0, helpers_1.validateSocksClientOptions)(options, ['connect']);
+            }
+            catch (err) {
+                if (typeof callback === 'function') {
+                    callback(err);
+                    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+                    return resolve(err); // Resolves pending promise (prevents memory leaks).
+                }
+                else {
+                    return reject(err);
+                }
+            }
+            const client = new SocksClient(options);
+            client.connect(options.existing_socket);
+            client.once('established', (info) => {
+                client.removeAllListeners();
+                if (typeof callback === 'function') {
+                    callback(null, info);
+                    resolve(info); // Resolves pending promise (prevents memory leaks).
+                }
+                else {
+                    resolve(info);
+                }
+            });
+            // Error occurred, failed to establish connection.
+            client.once('error', (err) => {
+                client.removeAllListeners();
+                if (typeof callback === 'function') {
+                    callback(err);
+                    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+                    resolve(err); // Resolves pending promise (prevents memory leaks).
+                }
+                else {
+                    reject(err);
+                }
+            });
+        });
+    }
+    /**
+     * Creates a new SOCKS connection chain to a destination host through 2 or more SOCKS proxies.
+     *
+     * Note: Supports callbacks and promises. Only supports the connect method.
+     * Note: Implemented via createConnection() factory function.
+     * @param options { SocksClientChainOptions } Options
+     * @param callback { Function } An optional callback function.
+     * @returns { Promise }
+     */
+    static createConnectionChain(options, callback) {
+        // eslint-disable-next-line no-async-promise-executor
+        return new Promise((resolve, reject) => __awaiter(this, void 0, void 0, function* () {
+            // Validate SocksClientChainOptions
+            try {
+                (0, helpers_1.validateSocksClientChainOptions)(options);
+            }
+            catch (err) {
+                if (typeof callback === 'function') {
+                    callback(err);
+                    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+                    return resolve(err); // Resolves pending promise (prevents memory leaks).
+                }
+                else {
+                    return reject(err);
+                }
+            }
+            // Shuffle proxies
+            if (options.randomizeChain) {
+                (0, util_1.shuffleArray)(options.proxies);
+            }
+            try {
+                let sock;
+                for (let i = 0; i < options.proxies.length; i++) {
+                    const nextProxy = options.proxies[i];
+                    // If we've reached the last proxy in the chain, the destination is the actual destination, otherwise it's the next proxy.
+                    const nextDestination = i === options.proxies.length - 1
+                        ? options.destination
+                        : {
+                            host: options.proxies[i + 1].host ||
+                                options.proxies[i + 1].ipaddress,
+                            port: options.proxies[i + 1].port,
+                        };
+                    // Creates the next connection in the chain.
+                    const result = yield SocksClient.createConnection({
+                        command: 'connect',
+                        proxy: nextProxy,
+                        destination: nextDestination,
+                        existing_socket: sock,
+                    });
+                    // If sock is undefined, assign it here.
+                    sock = sock || result.socket;
+                }
+                if (typeof callback === 'function') {
+                    callback(null, { socket: sock });
+                    resolve({ socket: sock }); // Resolves pending promise (prevents memory leaks).
+                }
+                else {
+                    resolve({ socket: sock });
+                }
+            }
+            catch (err) {
+                if (typeof callback === 'function') {
+                    callback(err);
+                    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+                    resolve(err); // Resolves pending promise (prevents memory leaks).
+                }
+                else {
+                    reject(err);
+                }
+            }
+        }));
+    }
+    /**
+     * Creates a SOCKS UDP Frame.
+     * @param options
+     */
+    static createUDPFrame(options) {
+        const buff = new smart_buffer_1.SmartBuffer();
+        buff.writeUInt16BE(0);
+        buff.writeUInt8(options.frameNumber || 0);
+        // IPv4/IPv6/Hostname
+        if (net.isIPv4(options.remoteHost.host)) {
+            buff.writeUInt8(constants_1.Socks5HostType.IPv4);
+            buff.writeUInt32BE((0, helpers_1.ipv4ToInt32)(options.remoteHost.host));
+        }
+        else if (net.isIPv6(options.remoteHost.host)) {
+            buff.writeUInt8(constants_1.Socks5HostType.IPv6);
+            buff.writeBuffer((0, helpers_1.ipToBuffer)(options.remoteHost.host));
+        }
+        else {
+            buff.writeUInt8(constants_1.Socks5HostType.Hostname);
+            buff.writeUInt8(Buffer.byteLength(options.remoteHost.host));
+            buff.writeString(options.remoteHost.host);
+        }
+        // Port
+        buff.writeUInt16BE(options.remoteHost.port);
+        // Data
+        buff.writeBuffer(options.data);
+        return buff.toBuffer();
+    }
+    /**
+     * Parses a SOCKS UDP frame.
+     * @param data
+     */
+    static parseUDPFrame(data) {
+        const buff = smart_buffer_1.SmartBuffer.fromBuffer(data);
+        buff.readOffset = 2;
+        const frameNumber = buff.readUInt8();
+        const hostType = buff.readUInt8();
+        let remoteHost;
+        if (hostType === constants_1.Socks5HostType.IPv4) {
+            remoteHost = (0, helpers_1.int32ToIpv4)(buff.readUInt32BE());
+        }
+        else if (hostType === constants_1.Socks5HostType.IPv6) {
+            remoteHost = ip_address_1.Address6.fromByteArray(Array.from(buff.readBuffer(16))).canonicalForm();
+        }
+        else {
+            remoteHost = buff.readString(buff.readUInt8());
+        }
+        const remotePort = buff.readUInt16BE();
+        return {
+            frameNumber,
+            remoteHost: {
+                host: remoteHost,
+                port: remotePort,
+            },
+            data: buff.readBuffer(),
+        };
+    }
+    /**
+     * Internal state setter. If the SocksClient is in an error state, it cannot be changed to a non error state.
+     */
+    setState(newState) {
+        if (this.state !== constants_1.SocksClientState.Error) {
+            this.state = newState;
+        }
+    }
+    /**
+     * Starts the connection establishment to the proxy and destination.
+     * @param existingSocket Connected socket to use instead of creating a new one (internal use).
+     */
+    connect(existingSocket) {
+        this.onDataReceived = (data) => this.onDataReceivedHandler(data);
+        this.onClose = () => this.onCloseHandler();
+        this.onError = (err) => this.onErrorHandler(err);
+        this.onConnect = () => this.onConnectHandler();
+        // Start timeout timer (defaults to 30 seconds)
+        const timer = setTimeout(() => this.onEstablishedTimeout(), this.options.timeout || constants_1.DEFAULT_TIMEOUT);
+        // check whether unref is available as it differs from browser to NodeJS (#33)
+        if (timer.unref && typeof timer.unref === 'function') {
+            timer.unref();
+        }
+        // If an existing socket is provided, use it to negotiate SOCKS handshake. Otherwise create a new Socket.
+        if (existingSocket) {
+            this.socket = existingSocket;
+        }
+        else {
+            this.socket = new net.Socket();
+        }
+        // Attach Socket error handlers.
+        this.socket.once('close', this.onClose);
+        this.socket.once('error', this.onError);
+        this.socket.once('connect', this.onConnect);
+        this.socket.on('data', this.onDataReceived);
+        this.setState(constants_1.SocksClientState.Connecting);
+        this.receiveBuffer = new receivebuffer_1.ReceiveBuffer();
+        if (existingSocket) {
+            this.socket.emit('connect');
+        }
+        else {
+            this.socket.connect(this.getSocketOptions());
+            if (this.options.set_tcp_nodelay !== undefined &&
+                this.options.set_tcp_nodelay !== null) {
+                this.socket.setNoDelay(!!this.options.set_tcp_nodelay);
+            }
+        }
+        // Listen for established event so we can re-emit any excess data received during handshakes.
+        this.prependOnceListener('established', (info) => {
+            setImmediate(() => {
+                if (this.receiveBuffer.length > 0) {
+                    const excessData = this.receiveBuffer.get(this.receiveBuffer.length);
+                    info.socket.emit('data', excessData);
+                }
+                info.socket.resume();
+            });
+        });
+    }
+    // Socket options (defaults host/port to options.proxy.host/options.proxy.port)
+    getSocketOptions() {
+        return Object.assign(Object.assign({}, this.options.socket_options), { host: this.options.proxy.host || this.options.proxy.ipaddress, port: this.options.proxy.port });
+    }
+    /**
+     * Handles internal Socks timeout callback.
+     * Note: If the Socks client is not BoundWaitingForConnection or Established, the connection will be closed.
+     */
+    onEstablishedTimeout() {
+        if (this.state !== constants_1.SocksClientState.Established &&
+            this.state !== constants_1.SocksClientState.BoundWaitingForConnection) {
+            this.closeSocket(constants_1.ERRORS.ProxyConnectionTimedOut);
+        }
+    }
+    /**
+     * Handles Socket connect event.
+     */
+    onConnectHandler() {
+        this.setState(constants_1.SocksClientState.Connected);
+        // Send initial handshake.
+        if (this.options.proxy.type === 4) {
+            this.sendSocks4InitialHandshake();
+        }
+        else {
+            this.sendSocks5InitialHandshake();
+        }
+        this.setState(constants_1.SocksClientState.SentInitialHandshake);
+    }
+    /**
+     * Handles Socket data event.
+     * @param data
+     */
+    onDataReceivedHandler(data) {
+        /*
+          All received data is appended to a ReceiveBuffer.
+          This makes sure that all the data we need is received before we attempt to process it.
+        */
+        this.receiveBuffer.append(data);
+        // Process data that we have.
+        this.processData();
+    }
+    /**
+     * Handles processing of the data we have received.
+     */
+    processData() {
+        // If we have enough data to process the next step in the SOCKS handshake, proceed.
+        while (this.state !== constants_1.SocksClientState.Established &&
+            this.state !== constants_1.SocksClientState.Error &&
+            this.receiveBuffer.length >= this.nextRequiredPacketBufferSize) {
+            // Sent initial handshake, waiting for response.
+            if (this.state === constants_1.SocksClientState.SentInitialHandshake) {
+                if (this.options.proxy.type === 4) {
+                    // Socks v4 only has one handshake response.
+                    this.handleSocks4FinalHandshakeResponse();
+                }
+                else {
+                    // Socks v5 has two handshakes, handle initial one here.
+                    this.handleInitialSocks5HandshakeResponse();
+                }
+                // Sent auth request for Socks v5, waiting for response.
+            }
+            else if (this.state === constants_1.SocksClientState.SentAuthentication) {
+                this.handleInitialSocks5AuthenticationHandshakeResponse();
+                // Sent final Socks v5 handshake, waiting for final response.
+            }
+            else if (this.state === constants_1.SocksClientState.SentFinalHandshake) {
+                this.handleSocks5FinalHandshakeResponse();
+                // Socks BIND established. Waiting for remote connection via proxy.
+            }
+            else if (this.state === constants_1.SocksClientState.BoundWaitingForConnection) {
+                if (this.options.proxy.type === 4) {
+                    this.handleSocks4IncomingConnectionResponse();
+                }
+                else {
+                    this.handleSocks5IncomingConnectionResponse();
+                }
+            }
+            else {
+                this.closeSocket(constants_1.ERRORS.InternalError);
+                break;
+            }
+        }
+    }
+    /**
+     * Handles Socket close event.
+     * @param had_error
+     */
+    onCloseHandler() {
+        this.closeSocket(constants_1.ERRORS.SocketClosed);
+    }
+    /**
+     * Handles Socket error event.
+     * @param err
+     */
+    onErrorHandler(err) {
+        this.closeSocket(err.message);
+    }
+    /**
+     * Removes internal event listeners on the underlying Socket.
+     */
+    removeInternalSocketHandlers() {
+        // Pauses data flow of the socket (this is internally resumed after 'established' is emitted)
+        this.socket.pause();
+        this.socket.removeListener('data', this.onDataReceived);
+        this.socket.removeListener('close', this.onClose);
+        this.socket.removeListener('error', this.onError);
+        this.socket.removeListener('connect', this.onConnect);
+    }
+    /**
+     * Closes and destroys the underlying Socket. Emits an error event.
+     * @param err { String } An error string to include in error event.
+     */
+    closeSocket(err) {
+        // Make sure only one 'error' event is fired for the lifetime of this SocksClient instance.
+        if (this.state !== constants_1.SocksClientState.Error) {
+            // Set internal state to Error.
+            this.setState(constants_1.SocksClientState.Error);
+            // Destroy Socket
+            this.socket.destroy();
+            // Remove internal listeners
+            this.removeInternalSocketHandlers();
+            // Fire 'error' event.
+            this.emit('error', new util_1.SocksClientError(err, this.options));
+        }
+    }
+    /**
+     * Sends initial Socks v4 handshake request.
+     */
+    sendSocks4InitialHandshake() {
+        const userId = this.options.proxy.userId || '';
+        const buff = new smart_buffer_1.SmartBuffer();
+        buff.writeUInt8(0x04);
+        buff.writeUInt8(constants_1.SocksCommand[this.options.command]);
+        buff.writeUInt16BE(this.options.destination.port);
+        // Socks 4 (IPv4)
+        if (net.isIPv4(this.options.destination.host)) {
+            buff.writeBuffer((0, helpers_1.ipToBuffer)(this.options.destination.host));
+            buff.writeStringNT(userId);
+            // Socks 4a (hostname)
+        }
+        else {
+            buff.writeUInt8(0x00);
+            buff.writeUInt8(0x00);
+            buff.writeUInt8(0x00);
+            buff.writeUInt8(0x01);
+            buff.writeStringNT(userId);
+            buff.writeStringNT(this.options.destination.host);
+        }
+        this.nextRequiredPacketBufferSize =
+            constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks4Response;
+        this.socket.write(buff.toBuffer());
+    }
+    /**
+     * Handles Socks v4 handshake response.
+     * @param data
+     */
+    handleSocks4FinalHandshakeResponse() {
+        const data = this.receiveBuffer.get(8);
+        if (data[1] !== constants_1.Socks4Response.Granted) {
+            this.closeSocket(`${constants_1.ERRORS.Socks4ProxyRejectedConnection} - (${constants_1.Socks4Response[data[1]]})`);
+        }
+        else {
+            // Bind response
+            if (constants_1.SocksCommand[this.options.command] === constants_1.SocksCommand.bind) {
+                const buff = smart_buffer_1.SmartBuffer.fromBuffer(data);
+                buff.readOffset = 2;
+                const remoteHost = {
+                    port: buff.readUInt16BE(),
+                    host: (0, helpers_1.int32ToIpv4)(buff.readUInt32BE()),
+                };
+                // If host is 0.0.0.0, set to proxy host.
+                if (remoteHost.host === '0.0.0.0') {
+                    remoteHost.host = this.options.proxy.ipaddress;
+                }
+                this.setState(constants_1.SocksClientState.BoundWaitingForConnection);
+                this.emit('bound', { remoteHost, socket: this.socket });
+                // Connect response
+            }
+            else {
+                this.setState(constants_1.SocksClientState.Established);
+                this.removeInternalSocketHandlers();
+                this.emit('established', { socket: this.socket });
+            }
+        }
+    }
+    /**
+     * Handles Socks v4 incoming connection request (BIND)
+     * @param data
+     */
+    handleSocks4IncomingConnectionResponse() {
+        const data = this.receiveBuffer.get(8);
+        if (data[1] !== constants_1.Socks4Response.Granted) {
+            this.closeSocket(`${constants_1.ERRORS.Socks4ProxyRejectedIncomingBoundConnection} - (${constants_1.Socks4Response[data[1]]})`);
+        }
+        else {
+            const buff = smart_buffer_1.SmartBuffer.fromBuffer(data);
+            buff.readOffset = 2;
+            const remoteHost = {
+                port: buff.readUInt16BE(),
+                host: (0, helpers_1.int32ToIpv4)(buff.readUInt32BE()),
+            };
+            this.setState(constants_1.SocksClientState.Established);
+            this.removeInternalSocketHandlers();
+            this.emit('established', { remoteHost, socket: this.socket });
+        }
+    }
+    /**
+     * Sends initial Socks v5 handshake request.
+     */
+    sendSocks5InitialHandshake() {
+        const buff = new smart_buffer_1.SmartBuffer();
+        // By default we always support no auth.
+        const supportedAuthMethods = [constants_1.Socks5Auth.NoAuth];
+        // We should only tell the proxy we support user/pass auth if auth info is actually provided.
+        // Note: As of Tor v0.3.5.7+, if user/pass auth is an option from the client, by default it will always take priority.
+        if (this.options.proxy.userId || this.options.proxy.password) {
+            supportedAuthMethods.push(constants_1.Socks5Auth.UserPass);
+        }
+        // Custom auth method?
+        if (this.options.proxy.custom_auth_method !== undefined) {
+            supportedAuthMethods.push(this.options.proxy.custom_auth_method);
+        }
+        // Build handshake packet
+        buff.writeUInt8(0x05);
+        buff.writeUInt8(supportedAuthMethods.length);
+        for (const authMethod of supportedAuthMethods) {
+            buff.writeUInt8(authMethod);
+        }
+        this.nextRequiredPacketBufferSize =
+            constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5InitialHandshakeResponse;
+        this.socket.write(buff.toBuffer());
+        this.setState(constants_1.SocksClientState.SentInitialHandshake);
+    }
+    /**
+     * Handles initial Socks v5 handshake response.
+     * @param data
+     */
+    handleInitialSocks5HandshakeResponse() {
+        const data = this.receiveBuffer.get(2);
+        if (data[0] !== 0x05) {
+            this.closeSocket(constants_1.ERRORS.InvalidSocks5IntiailHandshakeSocksVersion);
+        }
+        else if (data[1] === constants_1.SOCKS5_NO_ACCEPTABLE_AUTH) {
+            this.closeSocket(constants_1.ERRORS.InvalidSocks5InitialHandshakeNoAcceptedAuthType);
+        }
+        else {
+            // If selected Socks v5 auth method is no auth, send final handshake request.
+            if (data[1] === constants_1.Socks5Auth.NoAuth) {
+                this.socks5ChosenAuthType = constants_1.Socks5Auth.NoAuth;
+                this.sendSocks5CommandRequest();
+                // If selected Socks v5 auth method is user/password, send auth handshake.
+            }
+            else if (data[1] === constants_1.Socks5Auth.UserPass) {
+                this.socks5ChosenAuthType = constants_1.Socks5Auth.UserPass;
+                this.sendSocks5UserPassAuthentication();
+                // If selected Socks v5 auth method is the custom_auth_method, send custom handshake.
+            }
+            else if (data[1] === this.options.proxy.custom_auth_method) {
+                this.socks5ChosenAuthType = this.options.proxy.custom_auth_method;
+                this.sendSocks5CustomAuthentication();
+            }
+            else {
+                this.closeSocket(constants_1.ERRORS.InvalidSocks5InitialHandshakeUnknownAuthType);
+            }
+        }
+    }
+    /**
+     * Sends Socks v5 user & password auth handshake.
+     *
+     * Note: No auth and user/pass are currently supported.
+     */
+    sendSocks5UserPassAuthentication() {
+        const userId = this.options.proxy.userId || '';
+        const password = this.options.proxy.password || '';
+        const buff = new smart_buffer_1.SmartBuffer();
+        buff.writeUInt8(0x01);
+        buff.writeUInt8(Buffer.byteLength(userId));
+        buff.writeString(userId);
+        buff.writeUInt8(Buffer.byteLength(password));
+        buff.writeString(password);
+        this.nextRequiredPacketBufferSize =
+            constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5UserPassAuthenticationResponse;
+        this.socket.write(buff.toBuffer());
+        this.setState(constants_1.SocksClientState.SentAuthentication);
+    }
+    sendSocks5CustomAuthentication() {
+        return __awaiter(this, void 0, void 0, function* () {
+            this.nextRequiredPacketBufferSize =
+                this.options.proxy.custom_auth_response_size;
+            this.socket.write(yield this.options.proxy.custom_auth_request_handler());
+            this.setState(constants_1.SocksClientState.SentAuthentication);
+        });
+    }
+    handleSocks5CustomAuthHandshakeResponse(data) {
+        return __awaiter(this, void 0, void 0, function* () {
+            return yield this.options.proxy.custom_auth_response_handler(data);
+        });
+    }
+    handleSocks5AuthenticationNoAuthHandshakeResponse(data) {
+        return __awaiter(this, void 0, void 0, function* () {
+            return data[1] === 0x00;
+        });
+    }
+    handleSocks5AuthenticationUserPassHandshakeResponse(data) {
+        return __awaiter(this, void 0, void 0, function* () {
+            return data[1] === 0x00;
+        });
+    }
+    /**
+     * Handles Socks v5 auth handshake response.
+     * @param data
+     */
+    handleInitialSocks5AuthenticationHandshakeResponse() {
+        return __awaiter(this, void 0, void 0, function* () {
+            this.setState(constants_1.SocksClientState.ReceivedAuthenticationResponse);
+            let authResult = false;
+            if (this.socks5ChosenAuthType === constants_1.Socks5Auth.NoAuth) {
+                authResult = yield this.handleSocks5AuthenticationNoAuthHandshakeResponse(this.receiveBuffer.get(2));
+            }
+            else if (this.socks5ChosenAuthType === constants_1.Socks5Auth.UserPass) {
+                authResult =
+                    yield this.handleSocks5AuthenticationUserPassHandshakeResponse(this.receiveBuffer.get(2));
+            }
+            else if (this.socks5ChosenAuthType === this.options.proxy.custom_auth_method) {
+                authResult = yield this.handleSocks5CustomAuthHandshakeResponse(this.receiveBuffer.get(this.options.proxy.custom_auth_response_size));
+            }
+            if (!authResult) {
+                this.closeSocket(constants_1.ERRORS.Socks5AuthenticationFailed);
+            }
+            else {
+                this.sendSocks5CommandRequest();
+            }
+        });
+    }
+    /**
+     * Sends Socks v5 final handshake request.
+     */
+    sendSocks5CommandRequest() {
+        const buff = new smart_buffer_1.SmartBuffer();
+        buff.writeUInt8(0x05);
+        buff.writeUInt8(constants_1.SocksCommand[this.options.command]);
+        buff.writeUInt8(0x00);
+        // ipv4, ipv6, domain?
+        if (net.isIPv4(this.options.destination.host)) {
+            buff.writeUInt8(constants_1.Socks5HostType.IPv4);
+            buff.writeBuffer((0, helpers_1.ipToBuffer)(this.options.destination.host));
+        }
+        else if (net.isIPv6(this.options.destination.host)) {
+            buff.writeUInt8(constants_1.Socks5HostType.IPv6);
+            buff.writeBuffer((0, helpers_1.ipToBuffer)(this.options.destination.host));
+        }
+        else {
+            buff.writeUInt8(constants_1.Socks5HostType.Hostname);
+            buff.writeUInt8(this.options.destination.host.length);
+            buff.writeString(this.options.destination.host);
+        }
+        buff.writeUInt16BE(this.options.destination.port);
+        this.nextRequiredPacketBufferSize =
+            constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5ResponseHeader;
+        this.socket.write(buff.toBuffer());
+        this.setState(constants_1.SocksClientState.SentFinalHandshake);
+    }
+    /**
+     * Handles Socks v5 final handshake response.
+     * @param data
+     */
+    handleSocks5FinalHandshakeResponse() {
+        // Peek at available data (we need at least 5 bytes to get the hostname length)
+        const header = this.receiveBuffer.peek(5);
+        if (header[0] !== 0x05 || header[1] !== constants_1.Socks5Response.Granted) {
+            this.closeSocket(`${constants_1.ERRORS.InvalidSocks5FinalHandshakeRejected} - ${constants_1.Socks5Response[header[1]]}`);
+        }
+        else {
+            // Read address type
+            const addressType = header[3];
+            let remoteHost;
+            let buff;
+            // IPv4
+            if (addressType === constants_1.Socks5HostType.IPv4) {
+                // Check if data is available.
+                const dataNeeded = constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5ResponseIPv4;
+                if (this.receiveBuffer.length < dataNeeded) {
+                    this.nextRequiredPacketBufferSize = dataNeeded;
+                    return;
+                }
+                buff = smart_buffer_1.SmartBuffer.fromBuffer(this.receiveBuffer.get(dataNeeded).slice(4));
+                remoteHost = {
+                    host: (0, helpers_1.int32ToIpv4)(buff.readUInt32BE()),
+                    port: buff.readUInt16BE(),
+                };
+                // If given host is 0.0.0.0, assume remote proxy ip instead.
+                if (remoteHost.host === '0.0.0.0') {
+                    remoteHost.host = this.options.proxy.ipaddress;
+                }
+                // Hostname
+            }
+            else if (addressType === constants_1.Socks5HostType.Hostname) {
+                const hostLength = header[4];
+                const dataNeeded = constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5ResponseHostname(hostLength); // header + host length + host + port
+                // Check if data is available.
+                if (this.receiveBuffer.length < dataNeeded) {
+                    this.nextRequiredPacketBufferSize = dataNeeded;
+                    return;
+                }
+                buff = smart_buffer_1.SmartBuffer.fromBuffer(this.receiveBuffer.get(dataNeeded).slice(5));
+                remoteHost = {
+                    host: buff.readString(hostLength),
+                    port: buff.readUInt16BE(),
+                };
+                // IPv6
+            }
+            else if (addressType === constants_1.Socks5HostType.IPv6) {
+                // Check if data is available.
+                const dataNeeded = constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5ResponseIPv6;
+                if (this.receiveBuffer.length < dataNeeded) {
+                    this.nextRequiredPacketBufferSize = dataNeeded;
+                    return;
+                }
+                buff = smart_buffer_1.SmartBuffer.fromBuffer(this.receiveBuffer.get(dataNeeded).slice(4));
+                remoteHost = {
+                    host: ip_address_1.Address6.fromByteArray(Array.from(buff.readBuffer(16))).canonicalForm(),
+                    port: buff.readUInt16BE(),
+                };
+            }
+            // We have everything we need
+            this.setState(constants_1.SocksClientState.ReceivedFinalResponse);
+            // If using CONNECT, the client is now in the established state.
+            if (constants_1.SocksCommand[this.options.command] === constants_1.SocksCommand.connect) {
+                this.setState(constants_1.SocksClientState.Established);
+                this.removeInternalSocketHandlers();
+                this.emit('established', { remoteHost, socket: this.socket });
+            }
+            else if (constants_1.SocksCommand[this.options.command] === constants_1.SocksCommand.bind) {
+                /* If using BIND, the Socks client is now in BoundWaitingForConnection state.
+                   This means that the remote proxy server is waiting for a remote connection to the bound port. */
+                this.setState(constants_1.SocksClientState.BoundWaitingForConnection);
+                this.nextRequiredPacketBufferSize =
+                    constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5ResponseHeader;
+                this.emit('bound', { remoteHost, socket: this.socket });
+                /*
+                  If using Associate, the Socks client is now Established. And the proxy server is now accepting UDP packets at the
+                  given bound port. This initial Socks TCP connection must remain open for the UDP relay to continue to work.
+                */
+            }
+            else if (constants_1.SocksCommand[this.options.command] === constants_1.SocksCommand.associate) {
+                this.setState(constants_1.SocksClientState.Established);
+                this.removeInternalSocketHandlers();
+                this.emit('established', {
+                    remoteHost,
+                    socket: this.socket,
+                });
+            }
+        }
+    }
+    /**
+     * Handles Socks v5 incoming connection request (BIND).
+     */
+    handleSocks5IncomingConnectionResponse() {
+        // Peek at available data (we need at least 5 bytes to get the hostname length)
+        const header = this.receiveBuffer.peek(5);
+        if (header[0] !== 0x05 || header[1] !== constants_1.Socks5Response.Granted) {
+            this.closeSocket(`${constants_1.ERRORS.Socks5ProxyRejectedIncomingBoundConnection} - ${constants_1.Socks5Response[header[1]]}`);
+        }
+        else {
+            // Read address type
+            const addressType = header[3];
+            let remoteHost;
+            let buff;
+            // IPv4
+            if (addressType === constants_1.Socks5HostType.IPv4) {
+                // Check if data is available.
+                const dataNeeded = constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5ResponseIPv4;
+                if (this.receiveBuffer.length < dataNeeded) {
+                    this.nextRequiredPacketBufferSize = dataNeeded;
+                    return;
+                }
+                buff = smart_buffer_1.SmartBuffer.fromBuffer(this.receiveBuffer.get(dataNeeded).slice(4));
+                remoteHost = {
+                    host: (0, helpers_1.int32ToIpv4)(buff.readUInt32BE()),
+                    port: buff.readUInt16BE(),
+                };
+                // If given host is 0.0.0.0, assume remote proxy ip instead.
+                if (remoteHost.host === '0.0.0.0') {
+                    remoteHost.host = this.options.proxy.ipaddress;
+                }
+                // Hostname
+            }
+            else if (addressType === constants_1.Socks5HostType.Hostname) {
+                const hostLength = header[4];
+                const dataNeeded = constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5ResponseHostname(hostLength); // header + host length + port
+                // Check if data is available.
+                if (this.receiveBuffer.length < dataNeeded) {
+                    this.nextRequiredPacketBufferSize = dataNeeded;
+                    return;
+                }
+                buff = smart_buffer_1.SmartBuffer.fromBuffer(this.receiveBuffer.get(dataNeeded).slice(5));
+                remoteHost = {
+                    host: buff.readString(hostLength),
+                    port: buff.readUInt16BE(),
+                };
+                // IPv6
+            }
+            else if (addressType === constants_1.Socks5HostType.IPv6) {
+                // Check if data is available.
+                const dataNeeded = constants_1.SOCKS_INCOMING_PACKET_SIZES.Socks5ResponseIPv6;
+                if (this.receiveBuffer.length < dataNeeded) {
+                    this.nextRequiredPacketBufferSize = dataNeeded;
+                    return;
+                }
+                buff = smart_buffer_1.SmartBuffer.fromBuffer(this.receiveBuffer.get(dataNeeded).slice(4));
+                remoteHost = {
+                    host: ip_address_1.Address6.fromByteArray(Array.from(buff.readBuffer(16))).canonicalForm(),
+                    port: buff.readUInt16BE(),
+                };
+            }
+            this.setState(constants_1.SocksClientState.Established);
+            this.removeInternalSocketHandlers();
+            this.emit('established', { remoteHost, socket: this.socket });
+        }
+    }
+    get socksClientOptions() {
+        return Object.assign({}, this.options);
+    }
+}
+exports.SocksClient = SocksClient;
+//# sourceMappingURL=socksclient.js.map
\ No newline at end of file
diff --git a/server/node_modules/socks/build/client/socksclient.js.map b/server/node_modules/socks/build/client/socksclient.js.map
new file mode 100644
index 0000000..0cae2aa
--- /dev/null
+++ b/server/node_modules/socks/build/client/socksclient.js.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/server/node_modules/socks/build/common/constants.js b/server/node_modules/socks/build/common/constants.js
new file mode 100644
index 0000000..aaf1641
--- /dev/null
+++ b/server/node_modules/socks/build/common/constants.js
@@ -0,0 +1,108 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.SOCKS5_NO_ACCEPTABLE_AUTH = exports.SOCKS5_CUSTOM_AUTH_END = exports.SOCKS5_CUSTOM_AUTH_START = exports.SOCKS_INCOMING_PACKET_SIZES = exports.SocksClientState = exports.Socks5Response = exports.Socks5HostType = exports.Socks5Auth = exports.Socks4Response = exports.SocksCommand = exports.ERRORS = exports.DEFAULT_TIMEOUT = void 0;
+const DEFAULT_TIMEOUT = 30000;
+exports.DEFAULT_TIMEOUT = DEFAULT_TIMEOUT;
+// prettier-ignore
+const ERRORS = {
+    InvalidSocksCommand: 'An invalid SOCKS command was provided. Valid options are connect, bind, and associate.',
+    InvalidSocksCommandForOperation: 'An invalid SOCKS command was provided. Only a subset of commands are supported for this operation.',
+    InvalidSocksCommandChain: 'An invalid SOCKS command was provided. Chaining currently only supports the connect command.',
+    InvalidSocksClientOptionsDestination: 'An invalid destination host was provided.',
+    InvalidSocksClientOptionsExistingSocket: 'An invalid existing socket was provided. This should be an instance of stream.Duplex.',
+    InvalidSocksClientOptionsProxy: 'Invalid SOCKS proxy details were provided.',
+    InvalidSocksClientOptionsTimeout: 'An invalid timeout value was provided. Please enter a value above 0 (in ms).',
+    InvalidSocksClientOptionsProxiesLength: 'At least two socks proxies must be provided for chaining.',
+    InvalidSocksClientOptionsCustomAuthRange: 'Custom auth must be a value between 0x80 and 0xFE.',
+    InvalidSocksClientOptionsCustomAuthOptions: 'When a custom_auth_method is provided, custom_auth_request_handler, custom_auth_response_size, and custom_auth_response_handler must also be provided and valid.',
+    NegotiationError: 'Negotiation error',
+    SocketClosed: 'Socket closed',
+    ProxyConnectionTimedOut: 'Proxy connection timed out',
+    InternalError: 'SocksClient internal error (this should not happen)',
+    InvalidSocks4HandshakeResponse: 'Received invalid Socks4 handshake response',
+    Socks4ProxyRejectedConnection: 'Socks4 Proxy rejected connection',
+    InvalidSocks4IncomingConnectionResponse: 'Socks4 invalid incoming connection response',
+    Socks4ProxyRejectedIncomingBoundConnection: 'Socks4 Proxy rejected incoming bound connection',
+    InvalidSocks5InitialHandshakeResponse: 'Received invalid Socks5 initial handshake response',
+    InvalidSocks5IntiailHandshakeSocksVersion: 'Received invalid Socks5 initial handshake (invalid socks version)',
+    InvalidSocks5InitialHandshakeNoAcceptedAuthType: 'Received invalid Socks5 initial handshake (no accepted authentication type)',
+    InvalidSocks5InitialHandshakeUnknownAuthType: 'Received invalid Socks5 initial handshake (unknown authentication type)',
+    Socks5AuthenticationFailed: 'Socks5 Authentication failed',
+    InvalidSocks5FinalHandshake: 'Received invalid Socks5 final handshake response',
+    InvalidSocks5FinalHandshakeRejected: 'Socks5 proxy rejected connection',
+    InvalidSocks5IncomingConnectionResponse: 'Received invalid Socks5 incoming connection response',
+    Socks5ProxyRejectedIncomingBoundConnection: 'Socks5 Proxy rejected incoming bound connection',
+};
+exports.ERRORS = ERRORS;
+const SOCKS_INCOMING_PACKET_SIZES = {
+    Socks5InitialHandshakeResponse: 2,
+    Socks5UserPassAuthenticationResponse: 2,
+    // Command response + incoming connection (bind)
+    Socks5ResponseHeader: 5, // We need at least 5 to read the hostname length, then we wait for the address+port information.
+    Socks5ResponseIPv4: 10, // 4 header + 4 ip + 2 port
+    Socks5ResponseIPv6: 22, // 4 header + 16 ip + 2 port
+    Socks5ResponseHostname: (hostNameLength) => hostNameLength + 7, // 4 header + 1 host length + host + 2 port
+    // Command response + incoming connection (bind)
+    Socks4Response: 8, // 2 header + 2 port + 4 ip
+};
+exports.SOCKS_INCOMING_PACKET_SIZES = SOCKS_INCOMING_PACKET_SIZES;
+var SocksCommand;
+(function (SocksCommand) {
+    SocksCommand[SocksCommand["connect"] = 1] = "connect";
+    SocksCommand[SocksCommand["bind"] = 2] = "bind";
+    SocksCommand[SocksCommand["associate"] = 3] = "associate";
+})(SocksCommand || (exports.SocksCommand = SocksCommand = {}));
+var Socks4Response;
+(function (Socks4Response) {
+    Socks4Response[Socks4Response["Granted"] = 90] = "Granted";
+    Socks4Response[Socks4Response["Failed"] = 91] = "Failed";
+    Socks4Response[Socks4Response["Rejected"] = 92] = "Rejected";
+    Socks4Response[Socks4Response["RejectedIdent"] = 93] = "RejectedIdent";
+})(Socks4Response || (exports.Socks4Response = Socks4Response = {}));
+var Socks5Auth;
+(function (Socks5Auth) {
+    Socks5Auth[Socks5Auth["NoAuth"] = 0] = "NoAuth";
+    Socks5Auth[Socks5Auth["GSSApi"] = 1] = "GSSApi";
+    Socks5Auth[Socks5Auth["UserPass"] = 2] = "UserPass";
+})(Socks5Auth || (exports.Socks5Auth = Socks5Auth = {}));
+const SOCKS5_CUSTOM_AUTH_START = 0x80;
+exports.SOCKS5_CUSTOM_AUTH_START = SOCKS5_CUSTOM_AUTH_START;
+const SOCKS5_CUSTOM_AUTH_END = 0xfe;
+exports.SOCKS5_CUSTOM_AUTH_END = SOCKS5_CUSTOM_AUTH_END;
+const SOCKS5_NO_ACCEPTABLE_AUTH = 0xff;
+exports.SOCKS5_NO_ACCEPTABLE_AUTH = SOCKS5_NO_ACCEPTABLE_AUTH;
+var Socks5Response;
+(function (Socks5Response) {
+    Socks5Response[Socks5Response["Granted"] = 0] = "Granted";
+    Socks5Response[Socks5Response["Failure"] = 1] = "Failure";
+    Socks5Response[Socks5Response["NotAllowed"] = 2] = "NotAllowed";
+    Socks5Response[Socks5Response["NetworkUnreachable"] = 3] = "NetworkUnreachable";
+    Socks5Response[Socks5Response["HostUnreachable"] = 4] = "HostUnreachable";
+    Socks5Response[Socks5Response["ConnectionRefused"] = 5] = "ConnectionRefused";
+    Socks5Response[Socks5Response["TTLExpired"] = 6] = "TTLExpired";
+    Socks5Response[Socks5Response["CommandNotSupported"] = 7] = "CommandNotSupported";
+    Socks5Response[Socks5Response["AddressNotSupported"] = 8] = "AddressNotSupported";
+})(Socks5Response || (exports.Socks5Response = Socks5Response = {}));
+var Socks5HostType;
+(function (Socks5HostType) {
+    Socks5HostType[Socks5HostType["IPv4"] = 1] = "IPv4";
+    Socks5HostType[Socks5HostType["Hostname"] = 3] = "Hostname";
+    Socks5HostType[Socks5HostType["IPv6"] = 4] = "IPv6";
+})(Socks5HostType || (exports.Socks5HostType = Socks5HostType = {}));
+var SocksClientState;
+(function (SocksClientState) {
+    SocksClientState[SocksClientState["Created"] = 0] = "Created";
+    SocksClientState[SocksClientState["Connecting"] = 1] = "Connecting";
+    SocksClientState[SocksClientState["Connected"] = 2] = "Connected";
+    SocksClientState[SocksClientState["SentInitialHandshake"] = 3] = "SentInitialHandshake";
+    SocksClientState[SocksClientState["ReceivedInitialHandshakeResponse"] = 4] = "ReceivedInitialHandshakeResponse";
+    SocksClientState[SocksClientState["SentAuthentication"] = 5] = "SentAuthentication";
+    SocksClientState[SocksClientState["ReceivedAuthenticationResponse"] = 6] = "ReceivedAuthenticationResponse";
+    SocksClientState[SocksClientState["SentFinalHandshake"] = 7] = "SentFinalHandshake";
+    SocksClientState[SocksClientState["ReceivedFinalResponse"] = 8] = "ReceivedFinalResponse";
+    SocksClientState[SocksClientState["BoundWaitingForConnection"] = 9] = "BoundWaitingForConnection";
+    SocksClientState[SocksClientState["Established"] = 10] = "Established";
+    SocksClientState[SocksClientState["Disconnected"] = 11] = "Disconnected";
+    SocksClientState[SocksClientState["Error"] = 99] = "Error";
+})(SocksClientState || (exports.SocksClientState = SocksClientState = {}));
+//# sourceMappingURL=constants.js.map
\ No newline at end of file
diff --git a/server/node_modules/socks/build/common/constants.js.map b/server/node_modules/socks/build/common/constants.js.map
new file mode 100644
index 0000000..969af83
--- /dev/null
+++ b/server/node_modules/socks/build/common/constants.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"constants.js","sourceRoot":"","sources":["../../src/common/constants.ts"],"names":[],"mappings":";;;AAGA,MAAM,eAAe,GAAG,KAAK,CAAC;AAyM5B,0CAAe;AArMjB,kBAAkB;AAClB,MAAM,MAAM,GAAG;IACb,mBAAmB,EAAE,wFAAwF;IAC7G,+BAA+B,EAAE,oGAAoG;IACrI,wBAAwB,EAAE,8FAA8F;IACxH,oCAAoC,EAAE,2CAA2C;IACjF,uCAAuC,EAAE,uFAAuF;IAChI,8BAA8B,EAAE,4CAA4C;IAC5E,gCAAgC,EAAE,8EAA8E;IAChH,sCAAsC,EAAE,2DAA2D;IACnG,wCAAwC,EAAE,oDAAoD;IAC9F,0CAA0C,EAAE,kKAAkK;IAC9M,gBAAgB,EAAE,mBAAmB;IACrC,YAAY,EAAE,eAAe;IAC7B,uBAAuB,EAAE,4BAA4B;IACrD,aAAa,EAAE,qDAAqD;IACpE,8BAA8B,EAAE,4CAA4C;IAC5E,6BAA6B,EAAE,kCAAkC;IACjE,uCAAuC,EAAE,6CAA6C;IACtF,0CAA0C,EAAE,iDAAiD;IAC7F,qCAAqC,EAAE,oDAAoD;IAC3F,yCAAyC,EAAE,mEAAmE;IAC9G,+CAA+C,EAAE,6EAA6E;IAC9H,4CAA4C,EAAE,yEAAyE;IACvH,0BAA0B,EAAE,8BAA8B;IAC1D,2BAA2B,EAAE,kDAAkD;IAC/E,mCAAmC,EAAE,kCAAkC;IACvE,uCAAuC,EAAE,sDAAsD;IAC/F,0CAA0C,EAAE,iDAAiD;CAC9F,CAAC;AAyKA,wBAAM;AAvKR,MAAM,2BAA2B,GAAG;IAClC,8BAA8B,EAAE,CAAC;IACjC,oCAAoC,EAAE,CAAC;IACvC,gDAAgD;IAChD,oBAAoB,EAAE,CAAC,EAAE,iGAAiG;IAC1H,kBAAkB,EAAE,EAAE,EAAE,2BAA2B;IACnD,kBAAkB,EAAE,EAAE,EAAE,4BAA4B;IACpD,sBAAsB,EAAE,CAAC,cAAsB,EAAE,EAAE,CAAC,cAAc,GAAG,CAAC,EAAE,2CAA2C;IACnH,gDAAgD;IAChD,cAAc,EAAE,CAAC,EAAE,2BAA2B;CAC/C,CAAC;AA6KA,kEAA2B;AAzK7B,IAAK,YAIJ;AAJD,WAAK,YAAY;IACf,qDAAc,CAAA;IACd,+CAAW,CAAA;IACX,yDAAgB,CAAA;AAClB,CAAC,EAJI,YAAY,4BAAZ,YAAY,QAIhB;AAED,IAAK,cAKJ;AALD,WAAK,cAAc;IACjB,0DAAc,CAAA;IACd,wDAAa,CAAA;IACb,4DAAe,CAAA;IACf,sEAAoB,CAAA;AACtB,CAAC,EALI,cAAc,8BAAd,cAAc,QAKlB;AAED,IAAK,UAIJ;AAJD,WAAK,UAAU;IACb,+CAAa,CAAA;IACb,+CAAa,CAAA;IACb,mDAAe,CAAA;AACjB,CAAC,EAJI,UAAU,0BAAV,UAAU,QAId;AAED,MAAM,wBAAwB,GAAG,IAAI,CAAC;AAuJpC,4DAAwB;AAtJ1B,MAAM,sBAAsB,GAAG,IAAI,CAAC;AAuJlC,wDAAsB;AArJxB,MAAM,yBAAyB,GAAG,IAAI,CAAC;AAsJrC,8DAAyB;AApJ3B,IAAK,cAUJ;AAVD,WAAK,cAAc;IACjB,yDAAc,CAAA;IACd,yDAAc,CAAA;IACd,+DAAiB,CAAA;IACjB,+EAAyB,CAAA;IACzB,yEAAsB,CAAA;IACtB,6EAAwB,CAAA;IACxB,+DAAiB,CAAA;IACjB,iFAA0B,CAAA;IAC1B,iFAA0B,CAAA;AAC5B,CAAC,EAVI,cAAc,8BAAd,cAAc,QAUlB;AAED,IAAK,cAIJ;AAJD,WAAK,cAAc;IACjB,mDAAW,CAAA;IACX,2DAAe,CAAA;IACf,mDAAW,CAAA;AACb,CAAC,EAJI,cAAc,8BAAd,cAAc,QAIlB;AAED,IAAK,gBAcJ;AAdD,WAAK,gBAAgB;IACnB,6DAAW,CAAA;IACX,mEAAc,CAAA;IACd,iEAAa,CAAA;IACb,uFAAwB,CAAA;IACxB,+GAAoC,CAAA;IACpC,mFAAsB,CAAA;IACtB,2GAAkC,CAAA;IAClC,mFAAsB,CAAA;IACtB,yFAAyB,CAAA;IACzB,iGAA6B,CAAA;IAC7B,sEAAgB,CAAA;IAChB,wEAAiB,CAAA;IACjB,0DAAU,CAAA;AACZ,CAAC,EAdI,gBAAgB,gCAAhB,gBAAgB,QAcpB"}
\ No newline at end of file
diff --git a/server/node_modules/socks/build/common/helpers.js b/server/node_modules/socks/build/common/helpers.js
new file mode 100644
index 0000000..f0fcaf0
--- /dev/null
+++ b/server/node_modules/socks/build/common/helpers.js
@@ -0,0 +1,167 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.ipToBuffer = exports.int32ToIpv4 = exports.ipv4ToInt32 = exports.validateSocksClientChainOptions = exports.validateSocksClientOptions = void 0;
+const util_1 = require("./util");
+const constants_1 = require("./constants");
+const stream = require("stream");
+const ip_address_1 = require("ip-address");
+const net = require("net");
+/**
+ * Validates the provided SocksClientOptions
+ * @param options { SocksClientOptions }
+ * @param acceptedCommands { string[] } A list of accepted SocksProxy commands.
+ */
+function validateSocksClientOptions(options, acceptedCommands = ['connect', 'bind', 'associate']) {
+    // Check SOCKs command option.
+    if (!constants_1.SocksCommand[options.command]) {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksCommand, options);
+    }
+    // Check SocksCommand for acceptable command.
+    if (acceptedCommands.indexOf(options.command) === -1) {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksCommandForOperation, options);
+    }
+    // Check destination
+    if (!isValidSocksRemoteHost(options.destination)) {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsDestination, options);
+    }
+    // Check SOCKS proxy to use
+    if (!isValidSocksProxy(options.proxy)) {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsProxy, options);
+    }
+    // Validate custom auth (if set)
+    validateCustomProxyAuth(options.proxy, options);
+    // Check timeout
+    if (options.timeout && !isValidTimeoutValue(options.timeout)) {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsTimeout, options);
+    }
+    // Check existing_socket (if provided)
+    if (options.existing_socket &&
+        !(options.existing_socket instanceof stream.Duplex)) {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsExistingSocket, options);
+    }
+}
+exports.validateSocksClientOptions = validateSocksClientOptions;
+/**
+ * Validates the SocksClientChainOptions
+ * @param options { SocksClientChainOptions }
+ */
+function validateSocksClientChainOptions(options) {
+    // Only connect is supported when chaining.
+    if (options.command !== 'connect') {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksCommandChain, options);
+    }
+    // Check destination
+    if (!isValidSocksRemoteHost(options.destination)) {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsDestination, options);
+    }
+    // Validate proxies (length)
+    if (!(options.proxies &&
+        Array.isArray(options.proxies) &&
+        options.proxies.length >= 2)) {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsProxiesLength, options);
+    }
+    // Validate proxies
+    options.proxies.forEach((proxy) => {
+        if (!isValidSocksProxy(proxy)) {
+            throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsProxy, options);
+        }
+        // Validate custom auth (if set)
+        validateCustomProxyAuth(proxy, options);
+    });
+    // Check timeout
+    if (options.timeout && !isValidTimeoutValue(options.timeout)) {
+        throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsTimeout, options);
+    }
+}
+exports.validateSocksClientChainOptions = validateSocksClientChainOptions;
+function validateCustomProxyAuth(proxy, options) {
+    if (proxy.custom_auth_method !== undefined) {
+        // Invalid auth method range
+        if (proxy.custom_auth_method < constants_1.SOCKS5_CUSTOM_AUTH_START ||
+            proxy.custom_auth_method > constants_1.SOCKS5_CUSTOM_AUTH_END) {
+            throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsCustomAuthRange, options);
+        }
+        // Missing custom_auth_request_handler
+        if (proxy.custom_auth_request_handler === undefined ||
+            typeof proxy.custom_auth_request_handler !== 'function') {
+            throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsCustomAuthOptions, options);
+        }
+        // Missing custom_auth_response_size
+        if (proxy.custom_auth_response_size === undefined) {
+            throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsCustomAuthOptions, options);
+        }
+        // Missing/invalid custom_auth_response_handler
+        if (proxy.custom_auth_response_handler === undefined ||
+            typeof proxy.custom_auth_response_handler !== 'function') {
+            throw new util_1.SocksClientError(constants_1.ERRORS.InvalidSocksClientOptionsCustomAuthOptions, options);
+        }
+    }
+}
+/**
+ * Validates a SocksRemoteHost
+ * @param remoteHost { SocksRemoteHost }
+ */
+function isValidSocksRemoteHost(remoteHost) {
+    return (remoteHost &&
+        typeof remoteHost.host === 'string' &&
+        Buffer.byteLength(remoteHost.host) < 256 &&
+        typeof remoteHost.port === 'number' &&
+        remoteHost.port >= 0 &&
+        remoteHost.port <= 65535);
+}
+/**
+ * Validates a SocksProxy
+ * @param proxy { SocksProxy }
+ */
+function isValidSocksProxy(proxy) {
+    return (proxy &&
+        (typeof proxy.host === 'string' || typeof proxy.ipaddress === 'string') &&
+        typeof proxy.port === 'number' &&
+        proxy.port >= 0 &&
+        proxy.port <= 65535 &&
+        (proxy.type === 4 || proxy.type === 5));
+}
+/**
+ * Validates a timeout value.
+ * @param value { Number }
+ */
+function isValidTimeoutValue(value) {
+    return typeof value === 'number' && value > 0;
+}
+function ipv4ToInt32(ip) {
+    const address = new ip_address_1.Address4(ip);
+    // Convert the IPv4 address parts to an integer
+    return address.toArray().reduce((acc, part) => (acc << 8) + part, 0) >>> 0;
+}
+exports.ipv4ToInt32 = ipv4ToInt32;
+function int32ToIpv4(int32) {
+    // Extract each byte (octet) from the 32-bit integer
+    const octet1 = (int32 >>> 24) & 0xff;
+    const octet2 = (int32 >>> 16) & 0xff;
+    const octet3 = (int32 >>> 8) & 0xff;
+    const octet4 = int32 & 0xff;
+    // Combine the octets into a string in IPv4 format
+    return [octet1, octet2, octet3, octet4].join('.');
+}
+exports.int32ToIpv4 = int32ToIpv4;
+function ipToBuffer(ip) {
+    if (net.isIPv4(ip)) {
+        // Handle IPv4 addresses
+        const address = new ip_address_1.Address4(ip);
+        return Buffer.from(address.toArray());
+    }
+    else if (net.isIPv6(ip)) {
+        // Handle IPv6 addresses
+        const address = new ip_address_1.Address6(ip);
+        return Buffer.from(address
+            .canonicalForm()
+            .split(':')
+            .map((segment) => segment.padStart(4, '0'))
+            .join(''), 'hex');
+    }
+    else {
+        throw new Error('Invalid IP address format');
+    }
+}
+exports.ipToBuffer = ipToBuffer;
+//# sourceMappingURL=helpers.js.map
\ No newline at end of file
diff --git a/server/node_modules/socks/build/common/helpers.js.map b/server/node_modules/socks/build/common/helpers.js.map
new file mode 100644
index 0000000..830152f
--- /dev/null
+++ b/server/node_modules/socks/build/common/helpers.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"helpers.js","sourceRoot":"","sources":["../../src/common/helpers.ts"],"names":[],"mappings":";;;AAKA,iCAAwC;AACxC,2CAMqB;AACrB,iCAAiC;AACjC,2CAA8C;AAC9C,2BAA2B;AAE3B;;;;GAIG;AACH,SAAS,0BAA0B,CACjC,OAA2B,EAC3B,gBAAgB,GAAG,CAAC,SAAS,EAAE,MAAM,EAAE,WAAW,CAAC;IAEnD,8BAA8B;IAC9B,IAAI,CAAC,wBAAY,CAAC,OAAO,CAAC,OAAO,CAAC,EAAE,CAAC;QACnC,MAAM,IAAI,uBAAgB,CAAC,kBAAM,CAAC,mBAAmB,EAAE,OAAO,CAAC,CAAC;IAClE,CAAC;IAED,6CAA6C;IAC7C,IAAI,gBAAgB,CAAC,OAAO,CAAC,OAAO,CAAC,OAAO,CAAC,KAAK,CAAC,CAAC,EAAE,CAAC;QACrD,MAAM,IAAI,uBAAgB,CAAC,kBAAM,CAAC,+BAA+B,EAAE,OAAO,CAAC,CAAC;IAC9E,CAAC;IAED,oBAAoB;IACpB,IAAI,CAAC,sBAAsB,CAAC,OAAO,CAAC,WAAW,CAAC,EAAE,CAAC;QACjD,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,oCAAoC,EAC3C,OAAO,CACR,CAAC;IACJ,CAAC;IAED,2BAA2B;IAC3B,IAAI,CAAC,iBAAiB,CAAC,OAAO,CAAC,KAAK,CAAC,EAAE,CAAC;QACtC,MAAM,IAAI,uBAAgB,CAAC,kBAAM,CAAC,8BAA8B,EAAE,OAAO,CAAC,CAAC;IAC7E,CAAC;IAED,gCAAgC;IAChC,uBAAuB,CAAC,OAAO,CAAC,KAAK,EAAE,OAAO,CAAC,CAAC;IAEhD,gBAAgB;IAChB,IAAI,OAAO,CAAC,OAAO,IAAI,CAAC,mBAAmB,CAAC,OAAO,CAAC,OAAO,CAAC,EAAE,CAAC;QAC7D,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,gCAAgC,EACvC,OAAO,CACR,CAAC;IACJ,CAAC;IAED,sCAAsC;IACtC,IACE,OAAO,CAAC,eAAe;QACvB,CAAC,CAAC,OAAO,CAAC,eAAe,YAAY,MAAM,CAAC,MAAM,CAAC,EACnD,CAAC;QACD,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,uCAAuC,EAC9C,OAAO,CACR,CAAC;IACJ,CAAC;AACH,CAAC;AA8IO,gEAA0B;AA5IlC;;;GAGG;AACH,SAAS,+BAA+B,CAAC,OAAgC;IACvE,2CAA2C;IAC3C,IAAI,OAAO,CAAC,OAAO,KAAK,SAAS,EAAE,CAAC;QAClC,MAAM,IAAI,uBAAgB,CAAC,kBAAM,CAAC,wBAAwB,EAAE,OAAO,CAAC,CAAC;IACvE,CAAC;IAED,oBAAoB;IACpB,IAAI,CAAC,sBAAsB,CAAC,OAAO,CAAC,WAAW,CAAC,EAAE,CAAC;QACjD,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,oCAAoC,EAC3C,OAAO,CACR,CAAC;IACJ,CAAC;IAED,4BAA4B;IAC5B,IACE,CAAC,CACC,OAAO,CAAC,OAAO;QACf,KAAK,CAAC,OAAO,CAAC,OAAO,CAAC,OAAO,CAAC;QAC9B,OAAO,CAAC,OAAO,CAAC,MAAM,IAAI,CAAC,CAC5B,EACD,CAAC;QACD,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,sCAAsC,EAC7C,OAAO,CACR,CAAC;IACJ,CAAC;IAED,mBAAmB;IACnB,OAAO,CAAC,OAAO,CAAC,OAAO,CAAC,CAAC,KAAiB,EAAE,EAAE;QAC5C,IAAI,CAAC,iBAAiB,CAAC,KAAK,CAAC,EAAE,CAAC;YAC9B,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,8BAA8B,EACrC,OAAO,CACR,CAAC;QACJ,CAAC;QAED,gCAAgC;QAChC,uBAAuB,CAAC,KAAK,EAAE,OAAO,CAAC,CAAC;IAC1C,CAAC,CAAC,CAAC;IAEH,gBAAgB;IAChB,IAAI,OAAO,CAAC,OAAO,IAAI,CAAC,mBAAmB,CAAC,OAAO,CAAC,OAAO,CAAC,EAAE,CAAC;QAC7D,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,gCAAgC,EACvC,OAAO,CACR,CAAC;IACJ,CAAC;AACH,CAAC;AAwFmC,0EAA+B;AAtFnE,SAAS,uBAAuB,CAC9B,KAAiB,EACjB,OAAqD;IAErD,IAAI,KAAK,CAAC,kBAAkB,KAAK,SAAS,EAAE,CAAC;QAC3C,4BAA4B;QAC5B,IACE,KAAK,CAAC,kBAAkB,GAAG,oCAAwB;YACnD,KAAK,CAAC,kBAAkB,GAAG,kCAAsB,EACjD,CAAC;YACD,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,wCAAwC,EAC/C,OAAO,CACR,CAAC;QACJ,CAAC;QAED,sCAAsC;QACtC,IACE,KAAK,CAAC,2BAA2B,KAAK,SAAS;YAC/C,OAAO,KAAK,CAAC,2BAA2B,KAAK,UAAU,EACvD,CAAC;YACD,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,0CAA0C,EACjD,OAAO,CACR,CAAC;QACJ,CAAC;QAED,oCAAoC;QACpC,IAAI,KAAK,CAAC,yBAAyB,KAAK,SAAS,EAAE,CAAC;YAClD,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,0CAA0C,EACjD,OAAO,CACR,CAAC;QACJ,CAAC;QAED,+CAA+C;QAC/C,IACE,KAAK,CAAC,4BAA4B,KAAK,SAAS;YAChD,OAAO,KAAK,CAAC,4BAA4B,KAAK,UAAU,EACxD,CAAC;YACD,MAAM,IAAI,uBAAgB,CACxB,kBAAM,CAAC,0CAA0C,EACjD,OAAO,CACR,CAAC;QACJ,CAAC;IACH,CAAC;AACH,CAAC;AAED;;;GAGG;AACH,SAAS,sBAAsB,CAAC,UAA2B;IACzD,OAAO,CACL,UAAU;QACV,OAAO,UAAU,CAAC,IAAI,KAAK,QAAQ;QACnC,MAAM,CAAC,UAAU,CAAC,UAAU,CAAC,IAAI,CAAC,GAAG,GAAG;QACxC,OAAO,UAAU,CAAC,IAAI,KAAK,QAAQ;QACnC,UAAU,CAAC,IAAI,IAAI,CAAC;QACpB,UAAU,CAAC,IAAI,IAAI,KAAK,CACzB,CAAC;AACJ,CAAC;AAED;;;GAGG;AACH,SAAS,iBAAiB,CAAC,KAAiB;IAC1C,OAAO,CACL,KAAK;QACL,CAAC,OAAO,KAAK,CAAC,IAAI,KAAK,QAAQ,IAAI,OAAO,KAAK,CAAC,SAAS,KAAK,QAAQ,CAAC;QACvE,OAAO,KAAK,CAAC,IAAI,KAAK,QAAQ;QAC9B,KAAK,CAAC,IAAI,IAAI,CAAC;QACf,KAAK,CAAC,IAAI,IAAI,KAAK;QACnB,CAAC,KAAK,CAAC,IAAI,KAAK,CAAC,IAAI,KAAK,CAAC,IAAI,KAAK,CAAC,CAAC,CACvC,CAAC;AACJ,CAAC;AAED;;;GAGG;AACH,SAAS,mBAAmB,CAAC,KAAa;IACxC,OAAO,OAAO,KAAK,KAAK,QAAQ,IAAI,KAAK,GAAG,CAAC,CAAC;AAChD,CAAC;AAID,SAAgB,WAAW,CAAC,EAAU;IACpC,MAAM,OAAO,GAAG,IAAI,qBAAQ,CAAC,EAAE,CAAC,CAAC;IACjC,+CAA+C;IAC/C,OAAO,OAAO,CAAC,OAAO,EAAE,CAAC,MAAM,CAAC,CAAC,GAAG,EAAE,IAAI,EAAE,EAAE,CAAC,CAAC,GAAG,IAAI,CAAC,CAAC,GAAG,IAAI,EAAE,CAAC,CAAC,KAAK,CAAC,CAAC;AAC7E,CAAC;AAJD,kCAIC;AAED,SAAgB,WAAW,CAAC,KAAa;IACvC,oDAAoD;IACpD,MAAM,MAAM,GAAG,CAAC,KAAK,KAAK,EAAE,CAAC,GAAG,IAAI,CAAC;IACrC,MAAM,MAAM,GAAG,CAAC,KAAK,KAAK,EAAE,CAAC,GAAG,IAAI,CAAC;IACrC,MAAM,MAAM,GAAG,CAAC,KAAK,KAAK,CAAC,CAAC,GAAG,IAAI,CAAC;IACpC,MAAM,MAAM,GAAG,KAAK,GAAG,IAAI,CAAC;IAE5B,kDAAkD;IAClD,OAAO,CAAC,MAAM,EAAE,MAAM,EAAE,MAAM,EAAE,MAAM,CAAC,CAAC,IAAI,CAAC,GAAG,CAAC,CAAC;AACpD,CAAC;AATD,kCASC;AAED,SAAgB,UAAU,CAAC,EAAU;IACnC,IAAI,GAAG,CAAC,MAAM,CAAC,EAAE,CAAC,EAAE,CAAC;QACnB,wBAAwB;QACxB,MAAM,OAAO,GAAG,IAAI,qBAAQ,CAAC,EAAE,CAAC,CAAC;QACjC,OAAO,MAAM,CAAC,IAAI,CAAC,OAAO,CAAC,OAAO,EAAE,CAAC,CAAC;IACxC,CAAC;SAAM,IAAI,GAAG,CAAC,MAAM,CAAC,EAAE,CAAC,EAAE,CAAC;QAC1B,wBAAwB;QACxB,MAAM,OAAO,GAAG,IAAI,qBAAQ,CAAC,EAAE,CAAC,CAAC;QACjC,OAAO,MAAM,CAAC,IAAI,CAChB,OAAO;aACJ,aAAa,EAAE;aACf,KAAK,CAAC,GAAG,CAAC;aACV,GAAG,CAAC,CAAC,OAAO,EAAE,EAAE,CAAC,OAAO,CAAC,QAAQ,CAAC,CAAC,EAAE,GAAG,CAAC,CAAC;aAC1C,IAAI,CAAC,EAAE,CAAC,EACX,KAAK,CACN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\ No newline at end of file
diff --git a/server/node_modules/socks/build/common/receivebuffer.js b/server/node_modules/socks/build/common/receivebuffer.js
new file mode 100644
index 0000000..3dacbf9
--- /dev/null
+++ b/server/node_modules/socks/build/common/receivebuffer.js
@@ -0,0 +1,43 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.ReceiveBuffer = void 0;
+class ReceiveBuffer {
+    constructor(size = 4096) {
+        this.buffer = Buffer.allocUnsafe(size);
+        this.offset = 0;
+        this.originalSize = size;
+    }
+    get length() {
+        return this.offset;
+    }
+    append(data) {
+        if (!Buffer.isBuffer(data)) {
+            throw new Error('Attempted to append a non-buffer instance to ReceiveBuffer.');
+        }
+        if (this.offset + data.length >= this.buffer.length) {
+            const tmp = this.buffer;
+            this.buffer = Buffer.allocUnsafe(Math.max(this.buffer.length + this.originalSize, this.buffer.length + data.length));
+            tmp.copy(this.buffer);
+        }
+        data.copy(this.buffer, this.offset);
+        return (this.offset += data.length);
+    }
+    peek(length) {
+        if (length > this.offset) {
+            throw new Error('Attempted to read beyond the bounds of the managed internal data.');
+        }
+        return this.buffer.slice(0, length);
+    }
+    get(length) {
+        if (length > this.offset) {
+            throw new Error('Attempted to read beyond the bounds of the managed internal data.');
+        }
+        const value = Buffer.allocUnsafe(length);
+        this.buffer.slice(0, length).copy(value);
+        this.buffer.copyWithin(0, length, length + this.offset - length);
+        this.offset -= length;
+        return value;
+    }
+}
+exports.ReceiveBuffer = ReceiveBuffer;
+//# sourceMappingURL=receivebuffer.js.map
\ No newline at end of file
diff --git a/server/node_modules/socks/build/common/receivebuffer.js.map b/server/node_modules/socks/build/common/receivebuffer.js.map
new file mode 100644
index 0000000..ad86c8c
--- /dev/null
+++ b/server/node_modules/socks/build/common/receivebuffer.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"receivebuffer.js","sourceRoot":"","sources":["../../src/common/receivebuffer.ts"],"names":[],"mappings":";;;AAAA,MAAM,aAAa;IAKjB,YAAY,IAAI,GAAG,IAAI;QACrB,IAAI,CAAC,MAAM,GAAG,MAAM,CAAC,WAAW,CAAC,IAAI,CAAC,CAAC;QACvC,IAAI,CAAC,MAAM,GAAG,CAAC,CAAC;QAChB,IAAI,CAAC,YAAY,GAAG,IAAI,CAAC;IAC3B,CAAC;IAED,IAAI,MAAM;QACR,OAAO,IAAI,CAAC,MAAM,CAAC;IACrB,CAAC;IAED,MAAM,CAAC,IAAY;QACjB,IAAI,CAAC,MAAM,CAAC,QAAQ,CAAC,IAAI,CAAC,EAAE,CAAC;YAC3B,MAAM,IAAI,KAAK,CACb,6DAA6D,CAC9D,CAAC;QACJ,CAAC;QAED,IAAI,IAAI,CAAC,MAAM,GAAG,IAAI,CAAC,MAAM,IAAI,IAAI,CAAC,MAAM,CAAC,MAAM,EAAE,CAAC;YACpD,MAAM,GAAG,GAAG,IAAI,CAAC,MAAM,CAAC;YACxB,IAAI,CAAC,MAAM,GAAG,MAAM,CAAC,WAAW,CAC9B,IAAI,CAAC,GAAG,CACN,IAAI,CAAC,MAAM,CAAC,MAAM,GAAG,IAAI,CAAC,YAAY,EACtC,IAAI,CAAC,MAAM,CAAC,MAAM,GAAG,IAAI,CAAC,MAAM,CACjC,CACF,CAAC;YACF,GAAG,CAAC,IAAI,CAAC,IAAI,CAAC,MAAM,CAAC,CAAC;QACxB,CAAC;QAED,IAAI,CAAC,IAAI,CAAC,IAAI,CAAC,MAAM,EAAE,IAAI,CAAC,MAAM,CAAC,CAAC;QACpC,OAAO,CAAC,IAAI,CAAC,MAAM,IAAI,IAAI,CAAC,MAAM,CAAC,CAAC;IACtC,CAAC;IAED,IAAI,CAAC,MAAc;QACjB,IAAI,MAAM,GAAG,IAAI,CAAC,MAAM,EAAE,CAAC;YACzB,MAAM,IAAI,KAAK,CACb,mEAAmE,CACpE,CAAC;QACJ,CAAC;QACD,OAAO,IAAI,CAAC,MAAM,CAAC,KAAK,CAAC,CAAC,EAAE,MAAM,CAAC,CAAC;IACtC,CAAC;IAED,GAAG,CAAC,MAAc;QAChB,IAAI,MAAM,GAAG,IAAI,CAAC,MAAM,EAAE,CAAC;YACzB,MAAM,IAAI,KAAK,CACb,mEAAmE,CACpE,CAAC;QACJ,CAAC;QAED,MAAM,KAAK,GAAG,MAAM,CAAC,WAAW,CAAC,MAAM,CAAC,CAAC;QACzC,IAAI,CAAC,MAAM,CAAC,KAAK,CAAC,CAAC,EAAE,MAAM,CAAC,CAAC,IAAI,CAAC,KAAK,CAAC,CAAC;QACzC,IAAI,CAAC,MAAM,CAAC,UAAU,CAAC,CAAC,EAAE,MAAM,EAAE,MAAM,GAAG,IAAI,CAAC,MAAM,GAAG,MAAM,CAAC,CAAC;QACjE,IAAI,CAAC,MAAM,IAAI,MAAM,CAAC;QAEtB,OAAO,KAAK,CAAC;IACf,CAAC;CACF;AAEO,sCAAa"}
\ No newline at end of file
diff --git a/server/node_modules/socks/build/common/util.js b/server/node_modules/socks/build/common/util.js
new file mode 100644
index 0000000..f66b72e
--- /dev/null
+++ b/server/node_modules/socks/build/common/util.js
@@ -0,0 +1,25 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.shuffleArray = exports.SocksClientError = void 0;
+/**
+ * Error wrapper for SocksClient
+ */
+class SocksClientError extends Error {
+    constructor(message, options) {
+        super(message);
+        this.options = options;
+    }
+}
+exports.SocksClientError = SocksClientError;
+/**
+ * Shuffles a given array.
+ * @param array The array to shuffle.
+ */
+function shuffleArray(array) {
+    for (let i = array.length - 1; i > 0; i--) {
+        const j = Math.floor(Math.random() * (i + 1));
+        [array[i], array[j]] = [array[j], array[i]];
+    }
+}
+exports.shuffleArray = shuffleArray;
+//# sourceMappingURL=util.js.map
\ No newline at end of file
diff --git a/server/node_modules/socks/build/common/util.js.map b/server/node_modules/socks/build/common/util.js.map
new file mode 100644
index 0000000..21281b2
--- /dev/null
+++ b/server/node_modules/socks/build/common/util.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"util.js","sourceRoot":"","sources":["../../src/common/util.ts"],"names":[],"mappings":";;;AAEA;;GAEG;AACH,MAAM,gBAAiB,SAAQ,KAAK;IAClC,YACE,OAAe,EACR,OAAqD;QAE5D,KAAK,CAAC,OAAO,CAAC,CAAC;QAFR,YAAO,GAAP,OAAO,CAA8C;IAG9D,CAAC;CACF;AAaO,4CAAgB;AAXxB;;;GAGG;AACH,SAAS,YAAY,CAAC,KAAgB;IACpC,KAAK,IAAI,CAAC,GAAG,KAAK,CAAC,MAAM,GAAG,CAAC,EAAE,CAAC,GAAG,CAAC,EAAE,CAAC,EAAE,EAAE,CAAC;QAC1C,MAAM,CAAC,GAAG,IAAI,CAAC,KAAK,CAAC,IAAI,CAAC,MAAM,EAAE,GAAG,CAAC,CAAC,GAAG,CAAC,CAAC,CAAC,CAAC;QAC9C,CAAC,KAAK,CAAC,CAAC,CAAC,EAAE,KAAK,CAAC,CAAC,CAAC,CAAC,GAAG,CAAC,KAAK,CAAC,CAAC,CAAC,EAAE,KAAK,CAAC,CAAC,CAAC,CAAC,CAAC;IAC9C,CAAC;AACH,CAAC;AAEyB,oCAAY"}
\ No newline at end of file
diff --git a/server/node_modules/socks/build/index.js b/server/node_modules/socks/build/index.js
new file mode 100644
index 0000000..05fbb1d
--- /dev/null
+++ b/server/node_modules/socks/build/index.js
@@ -0,0 +1,18 @@
+"use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __exportStar = (this && this.__exportStar) || function(m, exports) {
+    for (var p in m) if (p !== "default" && !Object.prototype.hasOwnProperty.call(exports, p)) __createBinding(exports, m, p);
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+__exportStar(require("./client/socksclient"), exports);
+//# sourceMappingURL=index.js.map
\ No newline at end of file
diff --git a/server/node_modules/socks/build/index.js.map b/server/node_modules/socks/build/index.js.map
new file mode 100644
index 0000000..0e2bcb2
--- /dev/null
+++ b/server/node_modules/socks/build/index.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"index.js","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":";;;;;;;;;;;;;;;;AAAA,uDAAqC"}
\ No newline at end of file
diff --git a/server/node_modules/socks/docs/examples/index.md b/server/node_modules/socks/docs/examples/index.md
new file mode 100644
index 0000000..87bfe25
--- /dev/null
+++ b/server/node_modules/socks/docs/examples/index.md
@@ -0,0 +1,17 @@
+# socks examples
+
+## TypeScript Examples
+
+[Connect command](typescript/connectExample.md)
+
+[Bind command](typescript/bindExample.md)
+
+[Associate command](typescript/associateExample.md)
+
+## JavaScript Examples
+
+[Connect command](javascript/connectExample.md)
+
+[Bind command](javascript/bindExample.md)
+
+[Associate command](javascript/associateExample.md)
\ No newline at end of file
diff --git a/server/node_modules/socks/docs/examples/javascript/associateExample.md b/server/node_modules/socks/docs/examples/javascript/associateExample.md
new file mode 100644
index 0000000..c2c7b17
--- /dev/null
+++ b/server/node_modules/socks/docs/examples/javascript/associateExample.md
@@ -0,0 +1,90 @@
+# socks examples
+
+## Example for SOCKS 'associate' command
+
+The associate command tells the SOCKS proxy server to establish a UDP relay. The server binds to a new UDP port and communicates the newly opened port back to the origin client. From here, any SOCKS UDP frame packets sent to this special UDP port on the Proxy server will be forwarded to the desired destination, and any responses will be forwarded back to the origin client (you).
+
+This can be used for things such as DNS queries, and other UDP communicates.
+
+**Connection Steps**
+
+1. Client -(associate)-> Proxy (Tells the proxy to create a UDP relay and bind on a new port)
+2. Client <-(port)- Proxy (Tells the origin client which port it opened and is accepting UDP frame packets on)
+
+At this point the proxy is accepting UDP frames on the specified port.
+
+3. Client --(udp frame) -> Proxy -> Destination (The origin client sends a UDP frame to the proxy on the UDP port, and the proxy then forwards it to the destination specified in the UDP frame.)
+4. Client <--(udp frame) <-- Proxy <-- Destination (The destination client responds to the udp packet sent in #3)
+
+## Usage
+
+The 'associate' command can only be used by creating a new SocksClient instance and listening for the 'established' event.
+
+**Note:** UDP packets relayed through the proxy servers are encompassed in a special Socks UDP frame format. SocksClient.createUDPFrame() and SocksClient.parseUDPFrame() create and parse these special UDP packets.
+
+```typescript
+const dgram = require('dgram');
+const SocksClient = require('socks').SocksClient;
+
+// Create a local UDP socket for sending/receiving packets to/from the proxy.
+const udpSocket = dgram.createSocket('udp4');
+udpSocket.bind();
+
+// Listen for incoming UDP packets from the proxy server.
+udpSocket.on('message', (message, rinfo) => {
+  console.log(SocksClient.parseUDPFrame(message));
+  /*
+  { frameNumber: 0,
+    remoteHost: { host: '8.8.8.8', port: 53 }, // The remote host that replied with a UDP packet
+    data: <Buffer 74 65 73 74 0a> // The data
+  }
+  */
+});
+
+const options = {
+  proxy: {
+    host: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  // This should be the ip and port of the expected client that will be sending UDP frames to the newly opened UDP port on the server.
+  // Most SOCKS servers accept 0.0.0.0 as a wildcard address to accept UDP frames from any source.
+  destination: {
+    host: '0.0.0.0',
+    port: 0
+  },
+
+  command: 'associate'
+};
+
+const client = new SocksClient(options);
+
+// This event is fired when the SOCKS server has started listening on a new UDP port for UDP relaying.
+client.on('established', info => {
+  console.log(info);
+  /*
+  {
+    socket: <Socket ...>,
+    remoteHost: { // This is the remote port on the SOCKS proxy server to send UDP frame packets to.
+      host: '104.131.124.203',
+      port: 58232
+    }
+  }
+  */
+
+  // Send a udp frame to 8.8.8.8 on port 53 through the proxy.
+  const packet = SocksClient.createUDPFrame({
+    remoteHost: { host: '8.8.8.8', port: 53 },
+    data: Buffer.from('hello') // A DNS lookup in the real world.
+  });
+
+  // Send packet.
+  udpSocket.send(packet, info.remoteHost.port, info.remoteHost.host);
+});
+
+// SOCKS proxy failed to bind.
+client.on('error', () => {
+  // Handle errors
+});
+```
diff --git a/server/node_modules/socks/docs/examples/javascript/bindExample.md b/server/node_modules/socks/docs/examples/javascript/bindExample.md
new file mode 100644
index 0000000..be601d5
--- /dev/null
+++ b/server/node_modules/socks/docs/examples/javascript/bindExample.md
@@ -0,0 +1,83 @@
+# socks examples
+
+## Example for SOCKS 'bind' command
+
+The bind command tells the SOCKS proxy server to bind and listen on a new TCP port for an incoming connection. It communicates the newly opened port back to the origin client. Once a incoming connection is accepted by the SOCKS proxy server it then communicates the remote host that connected to the SOCKS proxy back through the same initial connection via the origin client.
+
+This can be used for things such as FTP clients which require incoming TCP connections, etc.
+
+**Connection Steps**
+
+1. Client -(bind)-> Proxy    (Tells the proxy to bind to a new port)
+2. Client <-(port)- Proxy    (Tells the origin client which port it opened)
+3. Client2 --> Proxy    (Other client connects to the proxy on this port)
+4. Client <--(client2's host info)  (Proxy tells the origin client who connected to it)
+5. Original connection to the proxy is now a full TCP stream between client (you) and client2.
+6. Client <--> Proxy <--> Client2
+
+
+## Usage
+
+The 'bind' command can only be used by creating a new SocksClient instance and listening for 'bound' and 'established' events.
+
+
+```typescript
+const SocksClient = require('socks').SocksClient;
+
+const options = {
+  proxy: {
+    host: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  // This should be the ip and port of the expected client that will connect to the SOCKS proxy server on the newly bound port.
+  // Most SOCKS servers accept 0.0.0.0 as a wildcard address to accept any client.
+  destination: {
+    host: '0.0.0.0',
+    port: 0
+  },
+
+  command: 'bind'
+};
+
+const client = new SocksClient(options);
+
+// This event is fired when the SOCKS server has started listening on a new port for incoming connections.
+client.on('bound', (info) => {
+  console.log(info);
+  /*
+  {
+    socket: <Socket ...>,
+    remoteHost: { // This is the remote ip and port of the SOCKS proxy that is now accepting incoming connections.
+      host: '104.131.124.203',
+      port: 49928
+    }
+  }
+  */
+});
+
+// This event is fired when the SOCKS server has accepted an incoming connection on the newly bound port.
+client.on('established', (info) => {
+  console.log(info);
+  /*
+  {
+    socket: <Socket ...>,
+    remoteHost: { // This is the remote ip and port that connected to the SOCKS proxy on the newly bound port.
+      host: '1.2.3.4',
+      port: 58232
+    }
+  }
+  */
+
+  // At this point info.socket is a regular net.Socket TCP connection between client and client2 (1.2.3.4) (the client which connected to the proxy on the newly bound port.)
+
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+});
+
+// SOCKS proxy failed to bind.
+client.on('error', () => {
+  // Handle errors
+});
+```
\ No newline at end of file
diff --git a/server/node_modules/socks/docs/examples/javascript/connectExample.md b/server/node_modules/socks/docs/examples/javascript/connectExample.md
new file mode 100644
index 0000000..66244c5
--- /dev/null
+++ b/server/node_modules/socks/docs/examples/javascript/connectExample.md
@@ -0,0 +1,258 @@
+# socks examples
+
+## Example for SOCKS 'connect' command
+
+The connect command is the most common use-case for a SOCKS proxy. This establishes a direct connection to a destination host through a proxy server. The destination host only has knowledge of the proxy server connecting to it and does not know about the origin client (you).
+
+**Origin Client (you) <-> Proxy Server <-> Destination Server**
+
+In this example, we are connecting to a web server on port 80, and sending a very basic HTTP request to receive a response. It's worth noting that there are many socks-http-agents that can be used with the node http module (and libraries such as request.js) to make this easier. This HTTP request is used as a simple example.
+
+The 'connect' command can be used via the SocksClient.createConnection() factory function as well as by creating a SocksClient instance and using event handlers.
+
+### Using createConnection with async/await
+
+Since SocksClient.createConnection returns a Promise, we can easily use async/await for flow control.
+
+```typescript
+const SocksClient = require('socks').SocksClient;
+
+const options  = {
+  proxy: {
+    host: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  destination: {
+    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
+    port: 80
+  },
+
+  command: 'connect'
+};
+
+async function start() {
+  try {
+    const info = await SocksClient.createConnection(options);
+
+    console.log(info.socket);
+    // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+
+    info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+    info.socket.on('data', (data) => {
+      console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
+      /*
+        HTTP/1.1 200 OK
+        Access-Control-Allow-Origin: *
+        Content-Type: application/json; charset=utf-8
+        Date: Sun, 24 Dec 2017 03:47:51 GMT
+        Content-Length: 300
+
+        {
+          "as":"AS14061 Digital Ocean, Inc.",
+          "city":"Clifton",
+          "country":"United States",
+          "countryCode":"US",
+          "isp":"Digital Ocean",
+          "lat":40.8326,
+          "lon":-74.1307,
+          "org":"Digital Ocean",
+          "query":"104.131.124.203",
+          "region":"NJ",
+          "regionName":"New Jersey",
+          "status":"success",
+          "timezone":"America/New_York",
+          "zip":"07014"
+        }
+      */
+  } catch (err) {
+    // Handle errors
+  }
+}
+
+start();
+```
+
+### Using createConnection with Promises
+
+```typescript
+const SocksClient = require('socks').SocksClient;
+
+const options  = {
+  proxy: {
+    ipaddress: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  destination: {
+    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
+    port: 80
+  },
+
+  command: 'connect'
+};
+
+SocksClient.createConnection(options)
+.then(info => {
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+
+  info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+  info.socket.on('data', (data) => {
+    console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
+    /*
+      HTTP/1.1 200 OK
+      Access-Control-Allow-Origin: *
+      Content-Type: application/json; charset=utf-8
+      Date: Sun, 24 Dec 2017 03:47:51 GMT
+      Content-Length: 300
+
+      {
+        "as":"AS14061 Digital Ocean, Inc.",
+        "city":"Clifton",
+        "country":"United States",
+        "countryCode":"US",
+        "isp":"Digital Ocean",
+        "lat":40.8326,
+        "lon":-74.1307,
+        "org":"Digital Ocean",
+        "query":"104.131.124.203",
+        "region":"NJ",
+        "regionName":"New Jersey",
+        "status":"success",
+        "timezone":"America/New_York",
+        "zip":"07014"
+      }
+    */
+})
+.catch(err => {
+  // handle errors
+});
+```
+
+### Using createConnection with callbacks
+
+SocksClient.createConnection() optionally accepts a callback function as a second parameter.
+
+**Note:** If a callback function is provided, a Promise is still returned from the function, but the promise will always resolve regardless of if there was en error. (tldr: Do not mix callbacks and Promises).
+
+```typescript
+const SocksClient = require('socks').SocksClient;
+
+const options  = {
+  proxy: {
+    ipaddress: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  destination: {
+    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
+    port: 80
+  },
+
+  command: 'connect'
+};
+
+SocksClient.createConnection(options, (err, info) => {
+  if (err) {
+    // handle errors
+  } else {
+    console.log(info.socket);
+    // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+
+    info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+    info.socket.on('data', (data) => {
+      console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
+      /*
+        HTTP/1.1 200 OK
+        Access-Control-Allow-Origin: *
+        Content-Type: application/json; charset=utf-8
+        Date: Sun, 24 Dec 2017 03:47:51 GMT
+        Content-Length: 300
+
+        {
+          "as":"AS14061 Digital Ocean, Inc.",
+          "city":"Clifton",
+          "country":"United States",
+          "countryCode":"US",
+          "isp":"Digital Ocean",
+          "lat":40.8326,
+          "lon":-74.1307,
+          "org":"Digital Ocean",
+          "query":"104.131.124.203",
+          "region":"NJ",
+          "regionName":"New Jersey",
+          "status":"success",
+          "timezone":"America/New_York",
+          "zip":"07014"
+        }
+      */
+  }
+})
+```
+
+### Using event handlers
+
+SocksClient also supports instance creation of a SocksClient. This allows for event based flow control.
+
+```typescript
+const SocksClient = require('socks').SocksClient;
+
+const options  = {
+  proxy: {
+    ipaddress: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  destination: {
+    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
+    port: 80
+  },
+
+  command: 'connect'
+};
+
+const client = new SocksClient(options);
+
+client.on('established', (info) => {
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+
+  info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+  info.socket.on('data', (data) => {
+    console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
+    /*
+      HTTP/1.1 200 OK
+      Access-Control-Allow-Origin: *
+      Content-Type: application/json; charset=utf-8
+      Date: Sun, 24 Dec 2017 03:47:51 GMT
+      Content-Length: 300
+
+      {
+        "as":"AS14061 Digital Ocean, Inc.",
+        "city":"Clifton",
+        "country":"United States",
+        "countryCode":"US",
+        "isp":"Digital Ocean",
+        "lat":40.8326,
+        "lon":-74.1307,
+        "org":"Digital Ocean",
+        "query":"104.131.124.203",
+        "region":"NJ",
+        "regionName":"New Jersey",
+        "status":"success",
+        "timezone":"America/New_York",
+        "zip":"07014"
+      }
+    */
+});
+
+// Failed to establish proxy connection to destination.
+client.on('error', () => {
+  // Handle errors
+});
+```
\ No newline at end of file
diff --git a/server/node_modules/socks/docs/examples/typescript/associateExample.md b/server/node_modules/socks/docs/examples/typescript/associateExample.md
new file mode 100644
index 0000000..e8ca193
--- /dev/null
+++ b/server/node_modules/socks/docs/examples/typescript/associateExample.md
@@ -0,0 +1,93 @@
+# socks examples
+
+## Example for SOCKS 'associate' command
+
+The associate command tells the SOCKS proxy server to establish a UDP relay. The server binds to a new UDP port and communicates the newly opened port back to the origin client. From here, any SOCKS UDP frame packets sent to this special UDP port on the Proxy server will be forwarded to the desired destination, and any responses will be forwarded back to the origin client (you).
+
+This can be used for things such as DNS queries, and other UDP communicates.
+
+**Connection Steps**
+
+1. Client -(associate)-> Proxy (Tells the proxy to create a UDP relay and bind on a new port)
+2. Client <-(port)- Proxy (Tells the origin client which port it opened and is accepting UDP frame packets on)
+
+At this point the proxy is accepting UDP frames on the specified port.
+
+3. Client --(udp frame) -> Proxy -> Destination (The origin client sends a UDP frame to the proxy on the UDP port, and the proxy then forwards it to the destination specified in the UDP frame.)
+4. Client <--(udp frame) <-- Proxy <-- Destination (The destination client responds to the udp packet sent in #3)
+
+## Usage
+
+The 'associate' command can only be used by creating a new SocksClient instance and listening for the 'established' event.
+
+**Note:** UDP packets relayed through the proxy servers are packaged in a special Socks UDP frame format. SocksClient.createUDPFrame() and SocksClient.parseUDPFrame() create and parse these special UDP packets.
+
+```typescript
+import * as dgram from 'dgram';
+import { SocksClient, SocksClientOptions } from 'socks';
+
+// Create a local UDP socket for sending/receiving packets to/from the proxy.
+const udpSocket = dgram.createSocket('udp4');
+udpSocket.bind();
+
+// Listen for incoming UDP packets from the proxy server.
+udpSocket.on('message', (message, rinfo) => {
+  console.log(SocksClient.parseUDPFrame(message));
+  /*
+  { frameNumber: 0,
+    remoteHost: { host: '8.8.8.8', port: 53 }, // The remote host that replied with a UDP packet
+    data: <Buffer 74 65 73 74 0a> // The data
+  }
+  */
+});
+
+const options: SocksClientOptions = {
+  proxy: {
+    host: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  // This should be the ip and port of the expected client that will be sending UDP frames to the newly opened UDP port on the server.
+  // Most SOCKS servers accept 0.0.0.0 as a wildcard address to accept UDP frames from any source.
+  destination: {
+    host: '0.0.0.0',
+    port: 0
+  },
+
+  command: 'associate'
+};
+
+const client = new SocksClient(options);
+
+// This event is fired when the SOCKS server has started listening on a new UDP port for UDP relaying.
+client.on('established', info => {
+  console.log(info);
+  /*
+  {
+    socket: <Socket ...>,
+    remoteHost: { // This is the remote port on the SOCKS proxy server to send UDP frame packets to.
+      host: '104.131.124.203',
+      port: 58232
+    }
+  }
+  */
+
+  // Send a udp frame to 8.8.8.8 on port 53 through the proxy.
+  const packet = SocksClient.createUDPFrame({
+    remoteHost: { host: '8.8.8.8', port: 53 },
+    data: Buffer.from('hello') // A DNS lookup in the real world.
+  });
+
+  // Send packet.
+  udpSocket.send(packet, info.remoteHost.port, info.remoteHost.host);
+});
+
+// SOCKS proxy failed to bind.
+client.on('error', () => {
+  // Handle errors
+});
+
+// Start connection
+client.connect();
+```
diff --git a/server/node_modules/socks/docs/examples/typescript/bindExample.md b/server/node_modules/socks/docs/examples/typescript/bindExample.md
new file mode 100644
index 0000000..6b7607d
--- /dev/null
+++ b/server/node_modules/socks/docs/examples/typescript/bindExample.md
@@ -0,0 +1,86 @@
+# socks examples
+
+## Example for SOCKS 'bind' command
+
+The bind command tells the SOCKS proxy server to bind and listen on a new TCP port for an incoming connection. It communicates the newly opened port back to the origin client. Once a incoming connection is accepted by the SOCKS proxy server it then communicates the remote host that connected to the SOCKS proxy back through the same initial connection via the origin client.
+
+This can be used for things such as FTP clients which require incoming TCP connections, etc.
+
+**Connection Steps**
+
+1. Client -(bind)-> Proxy    (Tells the proxy to bind to a new port)
+2. Client <-(port)- Proxy    (Tells the origin client which port it opened)
+3. Client2 --> Proxy    (Other client connects to the proxy on this port)
+4. Client <--(client2's host info)  (Proxy tells the origin client who connected to it)
+5. Original connection to the proxy is now a full TCP stream between client (you) and client2.
+6. Client <--> Proxy <--> Client2
+
+
+## Usage
+
+The 'bind' command can only be used by creating a new SocksClient instance and listening for 'bound' and 'established' events.
+
+
+```typescript
+import { SocksClient, SocksClientOptions } from 'socks';
+
+const options: SocksClientOptions = {
+  proxy: {
+    host: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  // This should be the ip and port of the expected client that will connect to the SOCKS proxy server on the newly bound port.
+  // Most SOCKS servers accept 0.0.0.0 as a wildcard address to accept any client.
+  destination: {
+    host: '0.0.0.0',
+    port: 0
+  },
+
+  command: 'bind'
+};
+
+const client = new SocksClient(options);
+
+// This event is fired when the SOCKS server has started listening on a new port for incoming connections.
+client.on('bound', (info) => {
+  console.log(info);
+  /*
+  {
+    socket: <Socket ...>,
+    remoteHost: { // This is the remote ip and port of the SOCKS proxy that is now accepting incoming connections.
+      host: '104.131.124.203',
+      port: 49928
+    }
+  }
+  */
+});
+
+// This event is fired when the SOCKS server has accepted an incoming connection on the newly bound port.
+client.on('established', (info) => {
+  console.log(info);
+  /*
+  {
+    socket: <Socket ...>,
+    remoteHost: { // This is the remote ip and port that connected to the SOCKS proxy on the newly bound port.
+      host: '1.2.3.4',
+      port: 58232
+    }
+  }
+  */
+
+  // At this point info.socket is a regular net.Socket TCP connection between client and client2 (1.2.3.4) (the client which connected to the proxy on the newly bound port.)
+
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+});
+
+// SOCKS proxy failed to bind.
+client.on('error', () => {
+  // Handle errors
+});
+
+// Start connection
+client.connect();
+```
\ No newline at end of file
diff --git a/server/node_modules/socks/docs/examples/typescript/connectExample.md b/server/node_modules/socks/docs/examples/typescript/connectExample.md
new file mode 100644
index 0000000..30606d0
--- /dev/null
+++ b/server/node_modules/socks/docs/examples/typescript/connectExample.md
@@ -0,0 +1,265 @@
+# socks examples
+
+## Example for SOCKS 'connect' command
+
+The connect command is the most common use-case for a SOCKS proxy. This establishes a direct connection to a destination host through a proxy server. The destination host only has knowledge of the proxy server connecting to it and does not know about the origin client (you).
+
+**Origin Client (you) <-> Proxy Server <-> Destination Server**
+
+In this example, we are connecting to a web server on port 80, and sending a very basic HTTP request to receive a response. It's worth noting that there are many socks-http-agents that can be used with the node http module (and libraries such as request.js) to make this easier. This HTTP request is used as a simple example.
+
+The 'connect' command can be used via the SocksClient.createConnection() factory function as well as by creating a SocksClient instance and using event handlers.
+
+### Using createConnection with async/await
+
+Since SocksClient.createConnection returns a Promise, we can easily use async/await for flow control.
+
+```typescript
+import { SocksClient, SocksClientOptions } from 'socks';
+
+const options: SocksClientOptions = {
+  proxy: {
+    host: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  destination: {
+    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
+    port: 80
+  },
+
+  command: 'connect'
+};
+
+async function start() {
+  try {
+    const info = await SocksClient.createConnection(options);
+
+    console.log(info.socket);
+    // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+
+    info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+    info.socket.on('data', (data) => {
+      console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
+      /*
+        HTTP/1.1 200 OK
+        Access-Control-Allow-Origin: *
+        Content-Type: application/json; charset=utf-8
+        Date: Sun, 24 Dec 2017 03:47:51 GMT
+        Content-Length: 300
+
+        {
+          "as":"AS14061 Digital Ocean, Inc.",
+          "city":"Clifton",
+          "country":"United States",
+          "countryCode":"US",
+          "isp":"Digital Ocean",
+          "lat":40.8326,
+          "lon":-74.1307,
+          "org":"Digital Ocean",
+          "query":"104.131.124.203",
+          "region":"NJ",
+          "regionName":"New Jersey",
+          "status":"success",
+          "timezone":"America/New_York",
+          "zip":"07014"
+        }
+      */
+    });
+  } catch (err) {
+    // Handle errors
+  }
+}
+
+start();
+```
+
+### Using createConnection with Promises
+
+```typescript
+import { SocksClient, SocksClientOptions } from 'socks';
+
+const options: SocksClientOptions = {
+  proxy: {
+    ipaddress: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  destination: {
+    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
+    port: 80
+  },
+
+  command: 'connect'
+};
+
+SocksClient.createConnection(options)
+.then(info => {
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+
+  info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+  info.socket.on('data', (data) => {
+    console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
+    /*
+      HTTP/1.1 200 OK
+      Access-Control-Allow-Origin: *
+      Content-Type: application/json; charset=utf-8
+      Date: Sun, 24 Dec 2017 03:47:51 GMT
+      Content-Length: 300
+
+      {
+        "as":"AS14061 Digital Ocean, Inc.",
+        "city":"Clifton",
+        "country":"United States",
+        "countryCode":"US",
+        "isp":"Digital Ocean",
+        "lat":40.8326,
+        "lon":-74.1307,
+        "org":"Digital Ocean",
+        "query":"104.131.124.203",
+        "region":"NJ",
+        "regionName":"New Jersey",
+        "status":"success",
+        "timezone":"America/New_York",
+        "zip":"07014"
+      }
+    */
+  });
+})
+.catch(err => {
+  // handle errors
+});
+```
+
+### Using createConnection with callbacks
+
+SocksClient.createConnection() optionally accepts a callback function as a second parameter.
+
+**Note:** If a callback function is provided, a Promise is still returned from the function, but the promise will always resolve regardless of if there was en error. (tldr: Do not mix callbacks and Promises).
+
+```typescript
+import { SocksClient, SocksClientOptions } from 'socks';
+
+const options: SocksClientOptions = {
+  proxy: {
+    ipaddress: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  destination: {
+    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
+    port: 80
+  },
+
+  command: 'connect'
+};
+
+SocksClient.createConnection(options, (err, info) => {
+  if (err) {
+    // handle errors
+  } else {
+    console.log(info.socket);
+    // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+
+    info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+    info.socket.on('data', (data) => {
+      console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
+      /*
+        HTTP/1.1 200 OK
+        Access-Control-Allow-Origin: *
+        Content-Type: application/json; charset=utf-8
+        Date: Sun, 24 Dec 2017 03:47:51 GMT
+        Content-Length: 300
+
+        {
+          "as":"AS14061 Digital Ocean, Inc.",
+          "city":"Clifton",
+          "country":"United States",
+          "countryCode":"US",
+          "isp":"Digital Ocean",
+          "lat":40.8326,
+          "lon":-74.1307,
+          "org":"Digital Ocean",
+          "query":"104.131.124.203",
+          "region":"NJ",
+          "regionName":"New Jersey",
+          "status":"success",
+          "timezone":"America/New_York",
+          "zip":"07014"
+        }
+      */
+    });
+  }
+})
+```
+
+### Using event handlers
+
+SocksClient also supports instance creation of a SocksClient. This allows for event based flow control.
+
+```typescript
+import { SocksClient, SocksClientOptions } from 'socks';
+
+const options: SocksClientOptions = {
+  proxy: {
+    ipaddress: '104.131.124.203',
+    port: 1081,
+    type: 5
+  },
+
+  destination: {
+    host: 'ip-api.com', // host names are supported with SOCKS v4a and SOCKS v5.
+    port: 80
+  },
+
+  command: 'connect'
+};
+
+const client = new SocksClient(options);
+
+client.on('established', (info) => {
+  console.log(info.socket);
+  // <Socket ...>  (this is a raw net.Socket that is established to the destination host through the given proxy servers)
+
+  info.socket.write('GET /json HTTP/1.1\nHost: ip-api.com\n\n');
+  info.socket.on('data', (data) => {
+    console.log(data.toString()); // ip-api.com sees that the last proxy (104.131.124.203) is connected to it and not the origin client (you).
+    /*
+      HTTP/1.1 200 OK
+      Access-Control-Allow-Origin: *
+      Content-Type: application/json; charset=utf-8
+      Date: Sun, 24 Dec 2017 03:47:51 GMT
+      Content-Length: 300
+
+      {
+        "as":"AS14061 Digital Ocean, Inc.",
+        "city":"Clifton",
+        "country":"United States",
+        "countryCode":"US",
+        "isp":"Digital Ocean",
+        "lat":40.8326,
+        "lon":-74.1307,
+        "org":"Digital Ocean",
+        "query":"104.131.124.203",
+        "region":"NJ",
+        "regionName":"New Jersey",
+        "status":"success",
+        "timezone":"America/New_York",
+        "zip":"07014"
+      }
+    */
+  });
+});
+
+// Failed to establish proxy connection to destination.
+client.on('error', () => {
+  // Handle errors
+});
+
+// Start connection
+client.connect();
+```
\ No newline at end of file
diff --git a/server/node_modules/socks/docs/index.md b/server/node_modules/socks/docs/index.md
new file mode 100644
index 0000000..3eb1d71
--- /dev/null
+++ b/server/node_modules/socks/docs/index.md
@@ -0,0 +1,5 @@
+# Documentation
+
+- [API Reference](https://github.com/JoshGlazebrook/socks#api-reference)
+
+- [Code Examples](./examples/index.md)
\ No newline at end of file
diff --git a/server/node_modules/socks/docs/migratingFromV1.md b/server/node_modules/socks/docs/migratingFromV1.md
new file mode 100644
index 0000000..dd00838
--- /dev/null
+++ b/server/node_modules/socks/docs/migratingFromV1.md
@@ -0,0 +1,86 @@
+# socks
+
+## Migrating from v1
+
+For the most part, migrating from v1 takes minimal effort as v2 still supports factory creation of proxy connections with callback support.
+
+### Notable breaking changes
+
+- In an options object, the proxy 'command' is now required and does not default to 'connect'.
+- **In an options object, 'target' is now known as 'destination'.**
+- Sockets are no longer paused after a SOCKS connection is made, so socket.resume() is no longer required. (Please be sure to attach data handlers immediately to the Socket to avoid losing data).
+- In v2, only the 'connect' command is supported via the factory SocksClient.createConnection function. (BIND and ASSOCIATE must be used with a SocksClient instance via event handlers).
+- In v2, the factory SocksClient.createConnection function callback is called with a single object rather than separate socket and info object.
+- A SOCKS http/https agent is no longer bundled into the library.
+
+For informational purposes, here is the original getting started example from v1 converted to work with v2.
+
+### Before (v1)
+
+```javascript
+var Socks = require('socks');
+
+var options = {
+    proxy: {
+        ipaddress: "202.101.228.108",
+        port: 1080,
+        type: 5
+    },
+    target: {
+        host: "google.com",
+        port: 80
+    },
+    command: 'connect'
+};
+
+Socks.createConnection(options, function(err, socket, info) {
+    if (err)
+        console.log(err);
+    else {
+        socket.write("GET / HTTP/1.1\nHost: google.com\n\n");
+        socket.on('data', function(data) {
+            console.log(data.length);
+            console.log(data);
+        });
+
+        // PLEASE NOTE: sockets need to be resumed before any data will come in or out as they are paused right before this callback is fired.
+        socket.resume();
+
+        // 569
+        // <Buffer 48 54 54 50 2f 31 2e 31 20 33 30 31 20 4d 6f 76 65 64 20 50 65...
+    }
+});
+```
+
+### After (v2)
+```javascript
+const SocksClient = require('socks').SocksClient;
+
+let options = {
+    proxy: {
+        ipaddress: "202.101.228.108",
+        port: 1080,
+        type: 5
+    },
+    destination: {
+        host: "google.com",
+        port: 80
+    },
+    command: 'connect'
+};
+
+SocksClient.createConnection(options, function(err, result) {
+    if (err)
+        console.log(err);
+    else {
+        result.socket.write("GET / HTTP/1.1\nHost: google.com\n\n");
+        result.socket.on('data', function(data) {
+            console.log(data.length);
+            console.log(data);
+        });
+
+        // 569
+        // <Buffer 48 54 54 50 2f 31 2e 31 20 33 30 31 20 4d 6f 76 65 64 20 50 65...
+    }
+});
+```
\ No newline at end of file
diff --git a/server/node_modules/socks/package.json b/server/node_modules/socks/package.json
new file mode 100644
index 0000000..a7a2a20
--- /dev/null
+++ b/server/node_modules/socks/package.json
@@ -0,0 +1,58 @@
+{
+  "name": "socks",
+  "private": false,
+  "version": "2.8.7",
+  "description": "Fully featured SOCKS proxy client supporting SOCKSv4, SOCKSv4a, and SOCKSv5. Includes Bind and Associate functionality.",
+  "main": "build/index.js",
+  "typings": "typings/index.d.ts",
+  "homepage": "https://github.com/JoshGlazebrook/socks/",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/JoshGlazebrook/socks.git"
+  },
+  "bugs": {
+    "url": "https://github.com/JoshGlazebrook/socks/issues"
+  },
+  "keywords": [
+    "socks",
+    "proxy",
+    "tor",
+    "socks 4",
+    "socks 5",
+    "socks4",
+    "socks5"
+  ],
+  "engines": {
+    "node": ">= 10.0.0",
+    "npm": ">= 3.0.0"
+  },
+  "author": "Josh Glazebrook",
+  "contributors": [
+    "castorw"
+  ],
+  "license": "MIT",
+  "readmeFilename": "README.md",
+  "devDependencies": {
+    "@types/mocha": "^10.0.6",
+    "@types/node": "^20.11.17",
+    "@typescript-eslint/eslint-plugin": "^6.21.0",
+    "@typescript-eslint/parser": "^6.21.0",
+    "eslint": "^8.20.0",
+    "mocha": "^10.0.0",
+    "prettier": "^3.2.5",
+    "ts-node": "^10.9.1",
+    "typescript": "^5.3.3"
+  },
+  "dependencies": {
+    "ip-address": "^10.0.1",
+    "smart-buffer": "^4.2.0"
+  },
+  "scripts": {
+    "prepublish": "npm install -g typescript && npm run build",
+    "test": "NODE_ENV=test mocha --recursive --require ts-node/register test/**/*.ts",
+    "prettier": "prettier --write ./src/**/*.ts --config .prettierrc.yaml",
+    "lint": "eslint 'src/**/*.ts'",
+    "build": "rm -rf build typings && prettier --write ./src/**/*.ts --config .prettierrc.yaml && tsc -p .",
+    "build-raw": "rm -rf build typings && tsc -p ."
+  }
+}
diff --git a/server/node_modules/socks/typings/client/socksclient.d.ts b/server/node_modules/socks/typings/client/socksclient.d.ts
new file mode 100644
index 0000000..b886d95
--- /dev/null
+++ b/server/node_modules/socks/typings/client/socksclient.d.ts
@@ -0,0 +1,162 @@
+/// <reference types="node" />
+/// <reference types="node" />
+/// <reference types="node" />
+import { EventEmitter } from 'events';
+import { SocksClientOptions, SocksClientChainOptions, SocksRemoteHost, SocksProxy, SocksClientBoundEvent, SocksClientEstablishedEvent, SocksUDPFrameDetails } from '../common/constants';
+import { SocksClientError } from '../common/util';
+import { Duplex } from 'stream';
+declare interface SocksClient {
+    on(event: 'error', listener: (err: SocksClientError) => void): this;
+    on(event: 'bound', listener: (info: SocksClientBoundEvent) => void): this;
+    on(event: 'established', listener: (info: SocksClientEstablishedEvent) => void): this;
+    once(event: string, listener: (...args: unknown[]) => void): this;
+    once(event: 'error', listener: (err: SocksClientError) => void): this;
+    once(event: 'bound', listener: (info: SocksClientBoundEvent) => void): this;
+    once(event: 'established', listener: (info: SocksClientEstablishedEvent) => void): this;
+    emit(event: string | symbol, ...args: unknown[]): boolean;
+    emit(event: 'error', err: SocksClientError): boolean;
+    emit(event: 'bound', info: SocksClientBoundEvent): boolean;
+    emit(event: 'established', info: SocksClientEstablishedEvent): boolean;
+}
+declare class SocksClient extends EventEmitter implements SocksClient {
+    private options;
+    private socket;
+    private state;
+    private receiveBuffer;
+    private nextRequiredPacketBufferSize;
+    private socks5ChosenAuthType;
+    private onDataReceived;
+    private onClose;
+    private onError;
+    private onConnect;
+    constructor(options: SocksClientOptions);
+    /**
+     * Creates a new SOCKS connection.
+     *
+     * Note: Supports callbacks and promises. Only supports the connect command.
+     * @param options { SocksClientOptions } Options.
+     * @param callback { Function } An optional callback function.
+     * @returns { Promise }
+     */
+    static createConnection(options: SocksClientOptions, callback?: (error: Error | null, info?: SocksClientEstablishedEvent) => void): Promise<SocksClientEstablishedEvent>;
+    /**
+     * Creates a new SOCKS connection chain to a destination host through 2 or more SOCKS proxies.
+     *
+     * Note: Supports callbacks and promises. Only supports the connect method.
+     * Note: Implemented via createConnection() factory function.
+     * @param options { SocksClientChainOptions } Options
+     * @param callback { Function } An optional callback function.
+     * @returns { Promise }
+     */
+    static createConnectionChain(options: SocksClientChainOptions, callback?: (error: Error | null, socket?: SocksClientEstablishedEvent) => void): Promise<SocksClientEstablishedEvent>;
+    /**
+     * Creates a SOCKS UDP Frame.
+     * @param options
+     */
+    static createUDPFrame(options: SocksUDPFrameDetails): Buffer;
+    /**
+     * Parses a SOCKS UDP frame.
+     * @param data
+     */
+    static parseUDPFrame(data: Buffer): SocksUDPFrameDetails;
+    /**
+     * Internal state setter. If the SocksClient is in an error state, it cannot be changed to a non error state.
+     */
+    private setState;
+    /**
+     * Starts the connection establishment to the proxy and destination.
+     * @param existingSocket Connected socket to use instead of creating a new one (internal use).
+     */
+    connect(existingSocket?: Duplex): void;
+    private getSocketOptions;
+    /**
+     * Handles internal Socks timeout callback.
+     * Note: If the Socks client is not BoundWaitingForConnection or Established, the connection will be closed.
+     */
+    private onEstablishedTimeout;
+    /**
+     * Handles Socket connect event.
+     */
+    private onConnectHandler;
+    /**
+     * Handles Socket data event.
+     * @param data
+     */
+    private onDataReceivedHandler;
+    /**
+     * Handles processing of the data we have received.
+     */
+    private processData;
+    /**
+     * Handles Socket close event.
+     * @param had_error
+     */
+    private onCloseHandler;
+    /**
+     * Handles Socket error event.
+     * @param err
+     */
+    private onErrorHandler;
+    /**
+     * Removes internal event listeners on the underlying Socket.
+     */
+    private removeInternalSocketHandlers;
+    /**
+     * Closes and destroys the underlying Socket. Emits an error event.
+     * @param err { String } An error string to include in error event.
+     */
+    private closeSocket;
+    /**
+     * Sends initial Socks v4 handshake request.
+     */
+    private sendSocks4InitialHandshake;
+    /**
+     * Handles Socks v4 handshake response.
+     * @param data
+     */
+    private handleSocks4FinalHandshakeResponse;
+    /**
+     * Handles Socks v4 incoming connection request (BIND)
+     * @param data
+     */
+    private handleSocks4IncomingConnectionResponse;
+    /**
+     * Sends initial Socks v5 handshake request.
+     */
+    private sendSocks5InitialHandshake;
+    /**
+     * Handles initial Socks v5 handshake response.
+     * @param data
+     */
+    private handleInitialSocks5HandshakeResponse;
+    /**
+     * Sends Socks v5 user & password auth handshake.
+     *
+     * Note: No auth and user/pass are currently supported.
+     */
+    private sendSocks5UserPassAuthentication;
+    private sendSocks5CustomAuthentication;
+    private handleSocks5CustomAuthHandshakeResponse;
+    private handleSocks5AuthenticationNoAuthHandshakeResponse;
+    private handleSocks5AuthenticationUserPassHandshakeResponse;
+    /**
+     * Handles Socks v5 auth handshake response.
+     * @param data
+     */
+    private handleInitialSocks5AuthenticationHandshakeResponse;
+    /**
+     * Sends Socks v5 final handshake request.
+     */
+    private sendSocks5CommandRequest;
+    /**
+     * Handles Socks v5 final handshake response.
+     * @param data
+     */
+    private handleSocks5FinalHandshakeResponse;
+    /**
+     * Handles Socks v5 incoming connection request (BIND).
+     */
+    private handleSocks5IncomingConnectionResponse;
+    get socksClientOptions(): SocksClientOptions;
+}
+export { SocksClient, SocksClientOptions, SocksClientChainOptions, SocksClientError, SocksRemoteHost, SocksProxy, SocksUDPFrameDetails, };
diff --git a/server/node_modules/socks/typings/common/constants.d.ts b/server/node_modules/socks/typings/common/constants.d.ts
new file mode 100644
index 0000000..475dee3
--- /dev/null
+++ b/server/node_modules/socks/typings/common/constants.d.ts
@@ -0,0 +1,151 @@
+/// <reference types="node" />
+/// <reference types="node" />
+/// <reference types="node" />
+import { Duplex } from 'stream';
+import { Socket, SocketConnectOpts } from 'net';
+declare const DEFAULT_TIMEOUT = 30000;
+type SocksProxyType = 4 | 5;
+declare const ERRORS: {
+    InvalidSocksCommand: string;
+    InvalidSocksCommandForOperation: string;
+    InvalidSocksCommandChain: string;
+    InvalidSocksClientOptionsDestination: string;
+    InvalidSocksClientOptionsExistingSocket: string;
+    InvalidSocksClientOptionsProxy: string;
+    InvalidSocksClientOptionsTimeout: string;
+    InvalidSocksClientOptionsProxiesLength: string;
+    InvalidSocksClientOptionsCustomAuthRange: string;
+    InvalidSocksClientOptionsCustomAuthOptions: string;
+    NegotiationError: string;
+    SocketClosed: string;
+    ProxyConnectionTimedOut: string;
+    InternalError: string;
+    InvalidSocks4HandshakeResponse: string;
+    Socks4ProxyRejectedConnection: string;
+    InvalidSocks4IncomingConnectionResponse: string;
+    Socks4ProxyRejectedIncomingBoundConnection: string;
+    InvalidSocks5InitialHandshakeResponse: string;
+    InvalidSocks5IntiailHandshakeSocksVersion: string;
+    InvalidSocks5InitialHandshakeNoAcceptedAuthType: string;
+    InvalidSocks5InitialHandshakeUnknownAuthType: string;
+    Socks5AuthenticationFailed: string;
+    InvalidSocks5FinalHandshake: string;
+    InvalidSocks5FinalHandshakeRejected: string;
+    InvalidSocks5IncomingConnectionResponse: string;
+    Socks5ProxyRejectedIncomingBoundConnection: string;
+};
+declare const SOCKS_INCOMING_PACKET_SIZES: {
+    Socks5InitialHandshakeResponse: number;
+    Socks5UserPassAuthenticationResponse: number;
+    Socks5ResponseHeader: number;
+    Socks5ResponseIPv4: number;
+    Socks5ResponseIPv6: number;
+    Socks5ResponseHostname: (hostNameLength: number) => number;
+    Socks4Response: number;
+};
+type SocksCommandOption = 'connect' | 'bind' | 'associate';
+declare enum SocksCommand {
+    connect = 1,
+    bind = 2,
+    associate = 3
+}
+declare enum Socks4Response {
+    Granted = 90,
+    Failed = 91,
+    Rejected = 92,
+    RejectedIdent = 93
+}
+declare enum Socks5Auth {
+    NoAuth = 0,
+    GSSApi = 1,
+    UserPass = 2
+}
+declare const SOCKS5_CUSTOM_AUTH_START = 128;
+declare const SOCKS5_CUSTOM_AUTH_END = 254;
+declare const SOCKS5_NO_ACCEPTABLE_AUTH = 255;
+declare enum Socks5Response {
+    Granted = 0,
+    Failure = 1,
+    NotAllowed = 2,
+    NetworkUnreachable = 3,
+    HostUnreachable = 4,
+    ConnectionRefused = 5,
+    TTLExpired = 6,
+    CommandNotSupported = 7,
+    AddressNotSupported = 8
+}
+declare enum Socks5HostType {
+    IPv4 = 1,
+    Hostname = 3,
+    IPv6 = 4
+}
+declare enum SocksClientState {
+    Created = 0,
+    Connecting = 1,
+    Connected = 2,
+    SentInitialHandshake = 3,
+    ReceivedInitialHandshakeResponse = 4,
+    SentAuthentication = 5,
+    ReceivedAuthenticationResponse = 6,
+    SentFinalHandshake = 7,
+    ReceivedFinalResponse = 8,
+    BoundWaitingForConnection = 9,
+    Established = 10,
+    Disconnected = 11,
+    Error = 99
+}
+/**
+ * Represents a SocksProxy
+ */
+interface SocksProxy {
+    ipaddress?: string;
+    host?: string;
+    port: number;
+    type: SocksProxyType;
+    userId?: string;
+    password?: string;
+    custom_auth_method?: number;
+    custom_auth_request_handler?: () => Promise<Buffer>;
+    custom_auth_response_size?: number;
+    custom_auth_response_handler?: (data: Buffer) => Promise<boolean>;
+}
+/**
+ * Represents a remote host
+ */
+interface SocksRemoteHost {
+    host: string;
+    port: number;
+}
+/**
+ * SocksClient connection options.
+ */
+interface SocksClientOptions {
+    command: SocksCommandOption;
+    destination: SocksRemoteHost;
+    proxy: SocksProxy;
+    timeout?: number;
+    existing_socket?: Duplex;
+    set_tcp_nodelay?: boolean;
+    socket_options?: SocketConnectOpts;
+}
+/**
+ * SocksClient chain connection options.
+ */
+interface SocksClientChainOptions {
+    command: 'connect';
+    destination: SocksRemoteHost;
+    proxies: SocksProxy[];
+    timeout?: number;
+    randomizeChain?: false;
+}
+interface SocksClientEstablishedEvent {
+    socket: Socket;
+    remoteHost?: SocksRemoteHost;
+}
+type SocksClientBoundEvent = SocksClientEstablishedEvent;
+interface SocksUDPFrameDetails {
+    frameNumber?: number;
+    remoteHost: SocksRemoteHost;
+    data: Buffer;
+}
+export { DEFAULT_TIMEOUT, ERRORS, SocksProxyType, SocksCommand, Socks4Response, Socks5Auth, Socks5HostType, Socks5Response, SocksClientState, SocksProxy, SocksRemoteHost, SocksCommandOption, SocksClientOptions, SocksClientChainOptions, SocksClientEstablishedEvent, SocksClientBoundEvent, SocksUDPFrameDetails, SOCKS_INCOMING_PACKET_SIZES, SOCKS5_CUSTOM_AUTH_START, SOCKS5_CUSTOM_AUTH_END, SOCKS5_NO_ACCEPTABLE_AUTH, };
diff --git a/server/node_modules/socks/typings/common/helpers.d.ts b/server/node_modules/socks/typings/common/helpers.d.ts
new file mode 100644
index 0000000..5bad9fe
--- /dev/null
+++ b/server/node_modules/socks/typings/common/helpers.d.ts
@@ -0,0 +1,17 @@
+/// <reference types="node" />
+import { SocksClientOptions, SocksClientChainOptions } from '../client/socksclient';
+/**
+ * Validates the provided SocksClientOptions
+ * @param options { SocksClientOptions }
+ * @param acceptedCommands { string[] } A list of accepted SocksProxy commands.
+ */
+declare function validateSocksClientOptions(options: SocksClientOptions, acceptedCommands?: string[]): void;
+/**
+ * Validates the SocksClientChainOptions
+ * @param options { SocksClientChainOptions }
+ */
+declare function validateSocksClientChainOptions(options: SocksClientChainOptions): void;
+export { validateSocksClientOptions, validateSocksClientChainOptions };
+export declare function ipv4ToInt32(ip: string): number;
+export declare function int32ToIpv4(int32: number): string;
+export declare function ipToBuffer(ip: string): Buffer;
diff --git a/server/node_modules/socks/typings/common/receivebuffer.d.ts b/server/node_modules/socks/typings/common/receivebuffer.d.ts
new file mode 100644
index 0000000..756e98b
--- /dev/null
+++ b/server/node_modules/socks/typings/common/receivebuffer.d.ts
@@ -0,0 +1,12 @@
+/// <reference types="node" />
+declare class ReceiveBuffer {
+    private buffer;
+    private offset;
+    private originalSize;
+    constructor(size?: number);
+    get length(): number;
+    append(data: Buffer): number;
+    peek(length: number): Buffer;
+    get(length: number): Buffer;
+}
+export { ReceiveBuffer };
diff --git a/server/node_modules/socks/typings/common/util.d.ts b/server/node_modules/socks/typings/common/util.d.ts
new file mode 100644
index 0000000..8612026
--- /dev/null
+++ b/server/node_modules/socks/typings/common/util.d.ts
@@ -0,0 +1,14 @@
+import { SocksClientOptions, SocksClientChainOptions } from './constants';
+/**
+ * Error wrapper for SocksClient
+ */
+declare class SocksClientError extends Error {
+    options: SocksClientOptions | SocksClientChainOptions;
+    constructor(message: string, options: SocksClientOptions | SocksClientChainOptions);
+}
+/**
+ * Shuffles a given array.
+ * @param array The array to shuffle.
+ */
+declare function shuffleArray(array: unknown[]): void;
+export { SocksClientError, shuffleArray };
diff --git a/server/node_modules/socks/typings/index.d.ts b/server/node_modules/socks/typings/index.d.ts
new file mode 100644
index 0000000..fbf9006
--- /dev/null
+++ b/server/node_modules/socks/typings/index.d.ts
@@ -0,0 +1 @@
+export * from './client/socksclient';
diff --git a/server/node_modules/sqlite3/LICENSE b/server/node_modules/sqlite3/LICENSE
new file mode 100644
index 0000000..6c4ce40
--- /dev/null
+++ b/server/node_modules/sqlite3/LICENSE
@@ -0,0 +1,25 @@
+Copyright (c) MapBox
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+- Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright notice, this
+  list of conditions and the following disclaimer in the documentation and/or
+  other materials provided with the distribution.
+- Neither the name "MapBox" nor the names of its contributors may be
+  used to endorse or promote products derived from this software without
+  specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
\ No newline at end of file
diff --git a/server/node_modules/sqlite3/README.md b/server/node_modules/sqlite3/README.md
new file mode 100644
index 0000000..ffc1f04
--- /dev/null
+++ b/server/node_modules/sqlite3/README.md
@@ -0,0 +1,249 @@
+# ⚙️ node-sqlite3
+
+Asynchronous, non-blocking [SQLite3](https://sqlite.org/) bindings for [Node.js](http://nodejs.org/).
+
+[![Latest release](https://img.shields.io/github/release/TryGhost/node-sqlite3.svg)](https://www.npmjs.com/package/sqlite3)
+![Build Status](https://github.com/TryGhost/node-sqlite3/workflows/CI/badge.svg?branch=master)
+[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bhttps%3A%2F%2Fgithub.com%2Fmapbox%2Fnode-sqlite3.svg?type=shield)](https://app.fossa.io/projects/git%2Bhttps%3A%2F%2Fgithub.com%2Fmapbox%2Fnode-sqlite3?ref=badge_shield)
+[![N-API v3 Badge](https://img.shields.io/badge/N--API-v3-green.svg)](https://nodejs.org/dist/latest/docs/api/n-api.html#n_api_n_api)
+[![N-API v6 Badge](https://img.shields.io/badge/N--API-v6-green.svg)](https://nodejs.org/dist/latest/docs/api/n-api.html#n_api_n_api)
+
+# Features
+
+ - Straightforward query and parameter binding interface
+ - Full Buffer/Blob support
+ - Extensive [debugging support](https://github.com/tryghost/node-sqlite3/wiki/Debugging)
+ - [Query serialization](https://github.com/tryghost/node-sqlite3/wiki/Control-Flow) API
+ - [Extension support](https://github.com/TryGhost/node-sqlite3/wiki/API#databaseloadextensionpath-callback), including bundled support for the [json1 extension](https://www.sqlite.org/json1.html)
+ - Big test suite
+ - Written in modern C++ and tested for memory leaks
+ - Bundles SQLite v3.44.2, or you can build using a local SQLite
+
+# Installing
+
+You can use [`npm`](https://github.com/npm/cli) or [`yarn`](https://github.com/yarnpkg/yarn) to install `sqlite3`:
+
+* (recommended) Latest published package:
+```bash
+npm install sqlite3
+# or
+yarn add sqlite3
+```
+* GitHub's `master` branch: `npm install https://github.com/tryghost/node-sqlite3/tarball/master`
+
+### Prebuilt binaries
+
+`sqlite3` v5+ was rewritten to use [Node-API](https://nodejs.org/api/n-api.html) so prebuilt binaries do not need to be built for specific Node versions. `sqlite3` currently builds for both Node-API v3 and v6. Check the [Node-API version matrix](https://nodejs.org/api/n-api.html#node-api-version-matrix) to ensure your Node version supports one of these. The prebuilt binaries should be supported on Node v10+.
+
+The module uses [`prebuild-install`](https://github.com/prebuild/prebuild-install) to download the prebuilt binary for your platform, if it exists. These binaries are hosted on GitHub Releases for `sqlite3` versions above 5.0.2, and they are hosted on S3 otherwise. The following targets are currently provided:
+
+* `darwin-arm64`
+* `darwin-x64`
+* `linux-arm64`
+* `linux-x64`
+* `linuxmusl-arm64`
+* `linuxmusl-x64`
+* `win32-ia32`
+* `win32-x64`
+
+Unfortunately, [prebuild](https://github.com/prebuild/prebuild/issues/174) cannot differentiate between `armv6` and `armv7`, and instead uses `arm` as the `{arch}`. Until that is fixed, you will still need to install `sqlite3` from [source](#source-install).
+
+Support for other platforms and architectures may be added in the future if CI supports building on them.
+
+If your environment isn't supported, it'll use `node-gyp` to build SQLite, but you will need to install a C++ compiler and linker.
+
+### Other ways to install
+
+It is also possible to make your own build of `sqlite3` from its source instead of its npm package ([See below.](#source-install)).
+
+The `sqlite3` module also works with [node-webkit](https://github.com/rogerwang/node-webkit) if node-webkit contains a supported version of Node.js engine. [(See below.)](#building-for-node-webkit)
+
+SQLite's [SQLCipher extension](https://github.com/sqlcipher/sqlcipher) is also supported. [(See below.)](#building-for-sqlcipher)
+
+# API
+
+See the [API documentation](https://github.com/TryGhost/node-sqlite3/wiki/API) in the wiki.
+
+# Usage
+
+**Note:** the module must be [installed](#installing) before use.
+
+``` js
+const sqlite3 = require('sqlite3').verbose();
+const db = new sqlite3.Database(':memory:');
+
+db.serialize(() => {
+    db.run("CREATE TABLE lorem (info TEXT)");
+
+    const stmt = db.prepare("INSERT INTO lorem VALUES (?)");
+    for (let i = 0; i < 10; i++) {
+        stmt.run("Ipsum " + i);
+    }
+    stmt.finalize();
+
+    db.each("SELECT rowid AS id, info FROM lorem", (err, row) => {
+        console.log(row.id + ": " + row.info);
+    });
+});
+
+db.close();
+```
+
+## Source install
+
+To skip searching for pre-compiled binaries, and force a build from source, use
+
+```bash
+npm install --build-from-source
+```
+
+The sqlite3 module depends only on libsqlite3. However, by default, an internal/bundled copy of sqlite will be built and statically linked, so an externally installed sqlite3 is not required.
+
+If you wish to install against an external sqlite then you need to pass the `--sqlite` argument to `npm` wrapper:
+
+```bash
+npm install --build-from-source --sqlite=/usr/local
+```
+
+If building against an external sqlite3 make sure to have the development headers available. Mac OS X ships with these by default. If you don't have them installed, install the `-dev` package with your package manager, e.g. `apt-get install libsqlite3-dev` for Debian/Ubuntu. Make sure that you have at least `libsqlite3` >= 3.6.
+
+Note, if building against homebrew-installed sqlite on OS X you can do:
+
+```bash
+npm install --build-from-source --sqlite=/usr/local/opt/sqlite/
+```
+
+## Custom file header (magic)
+
+The default sqlite file header is "SQLite format 3". You can specify a different magic, though this will make standard tools and libraries unable to work with your files.
+
+```bash
+npm install --build-from-source --sqlite_magic="MyCustomMagic15"
+```
+
+Note that the magic *must* be exactly 15 characters long (16 bytes including null terminator).
+
+## Building for node-webkit
+
+Because of ABI differences, `sqlite3` must be built in a custom to be used with [node-webkit](https://github.com/rogerwang/node-webkit).
+
+To build `sqlite3` for node-webkit:
+
+1. Install [`nw-gyp`](https://github.com/rogerwang/nw-gyp) globally: `npm install nw-gyp -g` *(unless already installed)*
+
+2. Build the module with the custom flags of `--runtime`, `--target_arch`, and `--target`:
+
+```bash
+NODE_WEBKIT_VERSION="0.8.6" # see latest version at https://github.com/rogerwang/node-webkit#downloads
+npm install sqlite3 --build-from-source --runtime=node-webkit --target_arch=ia32 --target=$(NODE_WEBKIT_VERSION)
+```
+
+You can also run this command from within a `sqlite3` checkout:
+
+```bash
+npm install --build-from-source --runtime=node-webkit --target_arch=ia32 --target=$(NODE_WEBKIT_VERSION)
+```
+
+Remember the following:
+
+* You must provide the right `--target_arch` flag. `ia32` is needed to target 32bit node-webkit builds, while `x64` will target 64bit node-webkit builds (if available for your platform).
+
+* After the `sqlite3` package is built for node-webkit it cannot run in the vanilla Node.js (and vice versa).
+   * For example, `npm test` of the node-webkit's package would fail.
+
+Visit the “[Using Node modules](https://github.com/rogerwang/node-webkit/wiki/Using-Node-modules)” article in the node-webkit's wiki for more details.
+
+## Building for SQLCipher
+
+For instructions on building SQLCipher, see [Building SQLCipher for Node.js](https://coolaj86.com/articles/building-sqlcipher-for-node-js-on-raspberry-pi-2/). Alternatively, you can install it with your local package manager.
+
+To run against SQLCipher, you need to compile `sqlite3` from source by passing build options like:
+
+```bash
+npm install sqlite3 --build-from-source --sqlite_libname=sqlcipher --sqlite=/usr/
+
+node -e 'require("sqlite3")'
+```
+
+If your SQLCipher is installed in a custom location (if you compiled and installed it yourself), you'll need to set some environment variables:
+
+### On OS X with Homebrew
+
+Set the location where `brew` installed it:
+
+```bash
+export LDFLAGS="-L`brew --prefix`/opt/sqlcipher/lib"
+export CPPFLAGS="-I`brew --prefix`/opt/sqlcipher/include/sqlcipher"
+npm install sqlite3 --build-from-source --sqlite_libname=sqlcipher --sqlite=`brew --prefix`
+
+node -e 'require("sqlite3")'
+```
+
+### On most Linuxes (including Raspberry Pi)
+
+Set the location where `make` installed it:
+
+```bash
+export LDFLAGS="-L/usr/local/lib"
+export CPPFLAGS="-I/usr/local/include -I/usr/local/include/sqlcipher"
+export CXXFLAGS="$CPPFLAGS"
+npm install sqlite3 --build-from-source --sqlite_libname=sqlcipher --sqlite=/usr/local --verbose
+
+node -e 'require("sqlite3")'
+```
+
+### Custom builds and Electron
+
+Running `sqlite3` through [electron-rebuild](https://github.com/electron/electron-rebuild) does not preserve the SQLCipher extension, so some additional flags are needed to make this build Electron compatible. Your `npm install sqlite3 --build-from-source` command needs these additional flags (be sure to replace the target version with the current Electron version you are working with):
+
+```bash
+--runtime=electron --target=18.2.1 --dist-url=https://electronjs.org/headers
+```
+
+In the case of MacOS with Homebrew, the command should look like the following:
+
+```bash
+npm install sqlite3 --build-from-source --sqlite_libname=sqlcipher --sqlite=`brew --prefix` --runtime=electron --target=18.2.1 --dist-url=https://electronjs.org/headers
+```
+
+# Testing
+
+```bash
+npm test
+```
+
+# Contributors
+
+* [Daniel Lockyer](https://github.com/daniellockyer)
+* [Konstantin Käfer](https://github.com/kkaefer)
+* [Dane Springmeyer](https://github.com/springmeyer)
+* [Will White](https://github.com/willwhite)
+* [Orlando Vazquez](https://github.com/orlandov)
+* [Artem Kustikov](https://github.com/artiz)
+* [Eric Fredricksen](https://github.com/grumdrig)
+* [John Wright](https://github.com/mrjjwright)
+* [Ryan Dahl](https://github.com/ry)
+* [Tom MacWright](https://github.com/tmcw)
+* [Carter Thaxton](https://github.com/carter-thaxton)
+* [Audrius Kažukauskas](https://github.com/audriusk)
+* [Johannes Schauer](https://github.com/pyneo)
+* [Mithgol](https://github.com/Mithgol)
+* [Kewde](https://github.com/kewde)
+
+# Acknowledgments
+
+Thanks to [Orlando Vazquez](https://github.com/orlandov),
+[Eric Fredricksen](https://github.com/grumdrig) and
+[Ryan Dahl](https://github.com/ry) for their SQLite bindings for node, and to mraleph on Freenode's #v8 for answering questions.
+
+This module was originally created by [Mapbox](https://mapbox.com/) & is now maintained by [Ghost](https://ghost.org).
+
+# Changelog
+
+We use [GitHub releases](https://github.com/TryGhost/node-sqlite3/releases) for notes on the latest versions. See [CHANGELOG.md](https://github.com/TryGhost/node-sqlite3/blob/b05f4594cf8b0de64743561fcd2cfe6f4571754d/CHANGELOG.md) in git history for details on older versions.
+
+# License
+
+`node-sqlite3` is [BSD licensed](https://github.com/tryghost/node-sqlite3/raw/master/LICENSE).
+
+[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bhttps%3A%2F%2Fgithub.com%2Fmapbox%2Fnode-sqlite3.svg?type=large)](https://app.fossa.io/projects/git%2Bhttps%3A%2F%2Fgithub.com%2Fmapbox%2Fnode-sqlite3?ref=badge_large)
diff --git a/server/node_modules/sqlite3/binding.gyp b/server/node_modules/sqlite3/binding.gyp
new file mode 100644
index 0000000..a8fccd0
--- /dev/null
+++ b/server/node_modules/sqlite3/binding.gyp
@@ -0,0 +1,58 @@
+{
+  "includes": [ "deps/common-sqlite.gypi" ],
+  "variables": {
+      "sqlite%":"internal",
+      "sqlite_libname%":"sqlite3",
+      "module_name": "node_sqlite3",
+  },
+  "targets": [
+    {
+      "target_name": "<(module_name)",
+      "cflags!": [ "-fno-exceptions" ],
+      "cflags_cc!": [ "-fno-exceptions" ],
+      "xcode_settings": { "GCC_ENABLE_CPP_EXCEPTIONS": "YES",
+        "CLANG_CXX_LIBRARY": "libc++",
+        "MACOSX_DEPLOYMENT_TARGET": "10.7",
+      },
+      "msvs_settings": {
+        "VCCLCompilerTool": { "ExceptionHandling": 1 },
+      },
+      "include_dirs": [
+        "<!@(node -p \"require('node-addon-api').include\")"],
+      "conditions": [
+        ["sqlite != 'internal'", {
+            "include_dirs": [
+              "<!@(node -p \"require('node-addon-api').include\")", "<(sqlite)/include" ],
+            "libraries": [
+               "-l<(sqlite_libname)"
+            ],
+            "conditions": [
+              [ "OS=='linux'", {"libraries+":["-Wl,-rpath=<@(sqlite)/lib"]} ],
+              [ "OS!='win'", {"libraries+":["-L<@(sqlite)/lib"]} ]
+            ],
+            'msvs_settings': {
+              'VCLinkerTool': {
+                'AdditionalLibraryDirectories': [
+                  '<(sqlite)/lib'
+                ],
+              },
+            }
+        },
+        {
+            "dependencies": [
+              "<!(node -p \"require('node-addon-api').gyp\")",
+              "deps/sqlite3.gyp:sqlite3"
+            ]
+        }
+        ]
+      ],
+      "sources": [
+        "src/backup.cc",
+        "src/database.cc",
+        "src/node_sqlite3.cc",
+        "src/statement.cc"
+      ],
+      "defines": [ "NAPI_VERSION=<(napi_build_version)", "NAPI_DISABLE_CPP_EXCEPTIONS=1" ]
+    }
+  ]
+}
diff --git a/server/node_modules/sqlite3/build/Release/node_sqlite3.node b/server/node_modules/sqlite3/build/Release/node_sqlite3.node
new file mode 100755
index 0000000..66137f1
Binary files /dev/null and b/server/node_modules/sqlite3/build/Release/node_sqlite3.node differ
diff --git a/server/node_modules/sqlite3/deps/common-sqlite.gypi b/server/node_modules/sqlite3/deps/common-sqlite.gypi
new file mode 100644
index 0000000..a04b1d5
--- /dev/null
+++ b/server/node_modules/sqlite3/deps/common-sqlite.gypi
@@ -0,0 +1,60 @@
+{
+  'variables': {
+      'sqlite_version%':'3440200',
+      "toolset%":'',
+  },
+  'target_defaults': {
+    'default_configuration': 'Release',
+    'conditions': [
+      [ 'toolset!=""', {
+        'msbuild_toolset':'<(toolset)'
+      }]
+    ],
+    'configurations': {
+      'Debug': {
+        'defines!': [
+          'NDEBUG'
+        ],
+        'cflags_cc!': [
+          '-O3',
+          '-Os',
+          '-DNDEBUG'
+        ],
+        'xcode_settings': {
+          'OTHER_CPLUSPLUSFLAGS!': [
+            '-O3',
+            '-Os',
+            '-DDEBUG'
+          ],
+          'GCC_OPTIMIZATION_LEVEL': '0',
+          'GCC_GENERATE_DEBUGGING_SYMBOLS': 'YES'
+        },
+        'msvs_settings': {
+          'VCCLCompilerTool': {
+            'ExceptionHandling': 1, # /EHsc
+          }
+        }
+      },
+      'Release': {
+        'defines': [
+          'NDEBUG'
+        ],
+        'xcode_settings': {
+          'OTHER_CPLUSPLUSFLAGS!': [
+            '-Os',
+            '-O2'
+          ],
+          'GCC_OPTIMIZATION_LEVEL': '3',
+          'GCC_GENERATE_DEBUGGING_SYMBOLS': 'NO',
+          'DEAD_CODE_STRIPPING': 'YES',
+          'GCC_INLINES_ARE_PRIVATE_EXTERN': 'YES'
+        },
+        'msvs_settings': {
+          'VCCLCompilerTool': {
+            'ExceptionHandling': 1, # /EHsc
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/server/node_modules/sqlite3/deps/extract.js b/server/node_modules/sqlite3/deps/extract.js
new file mode 100644
index 0000000..46aed47
--- /dev/null
+++ b/server/node_modules/sqlite3/deps/extract.js
@@ -0,0 +1,10 @@
+const tar = require("tar");
+const path = require("path");
+const tarball = path.resolve(process.argv[2]);
+const dirname = path.resolve(process.argv[3]);
+
+tar.extract({
+    sync: true,
+    file: tarball,
+    cwd: dirname,
+});
diff --git a/server/node_modules/sqlite3/deps/sqlite-autoconf-3440200.tar.gz b/server/node_modules/sqlite3/deps/sqlite-autoconf-3440200.tar.gz
new file mode 100644
index 0000000..701a614
Binary files /dev/null and b/server/node_modules/sqlite3/deps/sqlite-autoconf-3440200.tar.gz differ
diff --git a/server/node_modules/sqlite3/deps/sqlite3.gyp b/server/node_modules/sqlite3/deps/sqlite3.gyp
new file mode 100755
index 0000000..660b3b0
--- /dev/null
+++ b/server/node_modules/sqlite3/deps/sqlite3.gyp
@@ -0,0 +1,121 @@
+{
+  'includes': [ 'common-sqlite.gypi' ],
+
+  'variables': {
+    'sqlite_magic%': '',
+  },
+
+  'target_defaults': {
+    'default_configuration': 'Release',
+    'cflags':[
+      '-std=c99'
+    ],
+    'configurations': {
+      'Debug': {
+        'defines': [ 'DEBUG', '_DEBUG' ],
+        'msvs_settings': {
+          'VCCLCompilerTool': {
+            'RuntimeLibrary': 1, # static debug
+          },
+        },
+      },
+      'Release': {
+        'defines': [ 'NDEBUG' ],
+        'msvs_settings': {
+          'VCCLCompilerTool': {
+            'RuntimeLibrary': 0, # static release
+          },
+        },
+      }
+    },
+    'msvs_settings': {
+      'VCCLCompilerTool': {
+      },
+      'VCLibrarianTool': {
+      },
+      'VCLinkerTool': {
+        'GenerateDebugInformation': 'true',
+      },
+    },
+    'conditions': [
+      ['OS == "win"', {
+        'defines': [
+          'WIN32'
+        ],
+      }]
+    ],
+  },
+
+  'targets': [
+    {
+      'target_name': 'action_before_build',
+      'type': 'none',
+      'hard_dependency': 1,
+      'actions': [
+        {
+          'action_name': 'unpack_sqlite_dep',
+          'inputs': [
+            './sqlite-autoconf-<@(sqlite_version).tar.gz'
+          ],
+          'outputs': [
+            '<(SHARED_INTERMEDIATE_DIR)/sqlite-autoconf-<@(sqlite_version)/sqlite3.c'
+          ],
+          'action': ['node','./extract.js','./sqlite-autoconf-<@(sqlite_version).tar.gz','<(SHARED_INTERMEDIATE_DIR)']
+        }
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          '<(SHARED_INTERMEDIATE_DIR)/sqlite-autoconf-<@(sqlite_version)/',
+        ]
+      },
+    },
+    {
+      'target_name': 'sqlite3',
+      'type': 'static_library',
+      'include_dirs': [ '<(SHARED_INTERMEDIATE_DIR)/sqlite-autoconf-<@(sqlite_version)/' ],
+      'dependencies': [
+        'action_before_build'
+      ],
+      'sources': [
+        '<(SHARED_INTERMEDIATE_DIR)/sqlite-autoconf-<@(sqlite_version)/sqlite3.c'
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [ '<(SHARED_INTERMEDIATE_DIR)/sqlite-autoconf-<@(sqlite_version)/' ],
+        'defines': [
+          'SQLITE_THREADSAFE=1',
+          'HAVE_USLEEP=1',
+          'SQLITE_ENABLE_FTS3',
+          'SQLITE_ENABLE_FTS4',
+          'SQLITE_ENABLE_FTS5',
+          'SQLITE_ENABLE_RTREE',
+          'SQLITE_ENABLE_DBSTAT_VTAB=1',
+          'SQLITE_ENABLE_MATH_FUNCTIONS'
+        ],
+      },
+      'cflags_cc': [
+          '-Wno-unused-value'
+      ],
+      'defines': [
+        '_REENTRANT=1',
+        'SQLITE_THREADSAFE=1',
+        'HAVE_USLEEP=1',
+        'SQLITE_ENABLE_FTS3',
+        'SQLITE_ENABLE_FTS4',
+        'SQLITE_ENABLE_FTS5',
+        'SQLITE_ENABLE_RTREE',
+        'SQLITE_ENABLE_DBSTAT_VTAB=1',
+        'SQLITE_ENABLE_MATH_FUNCTIONS'
+      ],
+      'export_dependent_settings': [
+        'action_before_build',
+      ],
+      'conditions': [
+        ["sqlite_magic != ''", {
+            'defines': [
+              'SQLITE_FILE_HEADER="<(sqlite_magic)"'
+            ]
+        }]
+      ],
+    }
+  ]
+}
diff --git a/server/node_modules/sqlite3/lib/sqlite3-binding.js b/server/node_modules/sqlite3/lib/sqlite3-binding.js
new file mode 100644
index 0000000..98d1b91
--- /dev/null
+++ b/server/node_modules/sqlite3/lib/sqlite3-binding.js
@@ -0,0 +1 @@
+module.exports = require('bindings')('node_sqlite3.node');
diff --git a/server/node_modules/sqlite3/lib/sqlite3.d.ts b/server/node_modules/sqlite3/lib/sqlite3.d.ts
new file mode 100644
index 0000000..15e6623
--- /dev/null
+++ b/server/node_modules/sqlite3/lib/sqlite3.d.ts
@@ -0,0 +1,205 @@
+// Type definitions for sqlite3
+// Project: http://github.com/tryghost/node-sqlite3
+
+/// <reference types="node" />
+
+import events = require("events");
+
+export const OPEN_READONLY: number;
+export const OPEN_READWRITE: number;
+export const OPEN_CREATE: number;
+export const OPEN_FULLMUTEX: number;
+export const OPEN_SHAREDCACHE: number;
+export const OPEN_PRIVATECACHE: number;
+export const OPEN_URI: number;
+
+export const VERSION: string;
+export const SOURCE_ID: string;
+export const VERSION_NUMBER: number;
+
+export const OK: number;
+export const ERROR: number;
+export const INTERNAL: number;
+export const PERM: number;
+export const ABORT: number;
+export const BUSY: number;
+export const LOCKED: number;
+export const NOMEM: number;
+export const READONLY: number;
+export const INTERRUPT: number
+export const IOERR: number;
+export const CORRUPT: number
+export const NOTFOUND: number;
+export const FULL: number;
+export const CANTOPEN: number;
+export const PROTOCOL: number;
+export const EMPTY: number;
+export const SCHEMA: number;
+export const TOOBIG: number
+export const CONSTRAINT: number
+export const MISMATCH: number;
+export const MISUSE: number;
+export const NOLFS: number;
+export const AUTH: number
+export const FORMAT: number;
+export const RANGE: number
+export const NOTADB: number;
+
+export const LIMIT_LENGTH: number;
+export const LIMIT_SQL_LENGTH: number;
+export const LIMIT_COLUMN: number;
+export const LIMIT_EXPR_DEPTH: number;
+export const LIMIT_COMPOUND_SELECT: number;
+export const LIMIT_VDBE_OP: number;
+export const LIMIT_FUNCTION_ARG: number;
+export const LIMIT_ATTACHED: number;
+export const LIMIT_LIKE_PATTERN_LENGTH: number;
+export const LIMIT_VARIABLE_NUMBER: number;
+export const LIMIT_TRIGGER_DEPTH: number;
+export const LIMIT_WORKER_THREADS: number;
+
+export const cached: {
+    Database(filename: string, callback?: (this: Database, err: Error | null) => void): Database;
+    Database(filename: string, mode?: number, callback?: (this: Database, err: Error | null) => void): Database;
+};
+
+export interface RunResult extends Statement {
+    lastID: number;
+    changes: number;
+}
+
+export class Statement extends events.EventEmitter {
+    bind(callback?: (err: Error | null) => void): this;
+    bind(...params: any[]): this;
+
+    reset(callback?: (err: null) => void): this;
+
+    finalize(callback?: (err: Error) => void): Database;
+
+    run(callback?: (err: Error | null) => void): this;
+    run(params: any, callback?: (this: RunResult, err: Error | null) => void): this;
+    run(...params: any[]): this;
+
+    get<T>(callback?: (err: Error | null, row?: T) => void): this;
+    get<T>(params: any, callback?: (this: RunResult, err: Error | null, row?: T) => void): this;
+    get(...params: any[]): this;
+
+    all<T>(callback?: (err: Error | null, rows: T[]) => void): this;
+    all<T>(params: any, callback?: (this: RunResult, err: Error | null, rows: T[]) => void): this;
+    all(...params: any[]): this;
+
+    each<T>(callback?: (err: Error | null, row: T) => void, complete?: (err: Error | null, count: number) => void): this;
+    each<T>(params: any, callback?: (this: RunResult, err: Error | null, row: T) => void, complete?: (err: Error | null, count: number) => void): this;
+    each(...params: any[]): this;
+}
+
+export class Database extends events.EventEmitter {
+    constructor(filename: string, callback?: (err: Error | null) => void);
+    constructor(filename: string, mode?: number, callback?: (err: Error | null) => void);
+
+    close(callback?: (err: Error | null) => void): void;
+
+    run(sql: string, callback?: (this: RunResult, err: Error | null) => void): this;
+    run(sql: string, params: any, callback?: (this: RunResult, err: Error | null) => void): this;
+    run(sql: string, ...params: any[]): this;
+
+    get<T>(sql: string, callback?: (this: Statement, err: Error | null, row: T) => void): this;
+    get<T>(sql: string, params: any, callback?: (this: Statement, err: Error | null, row: T) => void): this;
+    get(sql: string, ...params: any[]): this;
+
+    all<T>(sql: string, callback?: (this: Statement, err: Error | null, rows: T[]) => void): this;
+    all<T>(sql: string, params: any, callback?: (this: Statement, err: Error | null, rows: T[]) => void): this;
+    all(sql: string, ...params: any[]): this;
+
+    each<T>(sql: string, callback?: (this: Statement, err: Error | null, row: T) => void, complete?: (err: Error | null, count: number) => void): this;
+    each<T>(sql: string, params: any, callback?: (this: Statement, err: Error | null, row: T) => void, complete?: (err: Error | null, count: number) => void): this;
+    each(sql: string, ...params: any[]): this;
+
+    exec(sql: string, callback?: (this: Statement, err: Error | null) => void): this;
+
+    prepare(sql: string, callback?: (this: Statement, err: Error | null) => void): Statement;
+    prepare(sql: string, params: any, callback?: (this: Statement, err: Error | null) => void): Statement;
+    prepare(sql: string, ...params: any[]): Statement;
+
+    serialize(callback?: () => void): void;
+    parallelize(callback?: () => void): void;
+
+    on(event: "trace", listener: (sql: string) => void): this;
+    on(event: "profile", listener: (sql: string, time: number) => void): this;
+    on(event: "change", listener: (type: string, database: string, table: string, rowid: number) => void): this;
+    on(event: "error", listener: (err: Error) => void): this;
+    on(event: "open" | "close", listener: () => void): this;
+    on(event: string, listener: (...args: any[]) => void): this;
+
+    configure(option: "busyTimeout", value: number): void;
+    configure(option: "limit", id: number, value: number): void;
+
+    loadExtension(filename: string, callback?: (err: Error | null) => void): this;
+
+    wait(callback?: (param: null) => void): this;
+
+    interrupt(): void;
+}
+
+export function verbose(): sqlite3;
+
+export interface sqlite3 {
+    OPEN_READONLY: number;
+    OPEN_READWRITE: number;
+    OPEN_CREATE: number;
+    OPEN_FULLMUTEX: number;
+    OPEN_SHAREDCACHE: number;
+    OPEN_PRIVATECACHE: number;
+    OPEN_URI: number;
+
+    VERSION: string;
+    SOURCE_ID: string;
+    VERSION_NUMBER: number;
+
+    OK: number;
+    ERROR: number;
+    INTERNAL: number;
+    PERM: number;
+    ABORT: number;
+    BUSY: number;
+    LOCKED: number;
+    NOMEM: number;
+    READONLY: number;
+    INTERRUPT: number
+    IOERR: number;
+    CORRUPT: number
+    NOTFOUND: number;
+    FULL: number;
+    CANTOPEN: number;
+    PROTOCOL: number;
+    EMPTY: number;
+    SCHEMA: number;
+    TOOBIG: number
+    CONSTRAINT: number
+    MISMATCH: number;
+    MISUSE: number;
+    NOLFS: number;
+    AUTH: number
+    FORMAT: number;
+    RANGE: number
+    NOTADB: number;
+
+    LIMIT_LENGTH: number;
+    LIMIT_SQL_LENGTH: number;
+    LIMIT_COLUMN: number;
+    LIMIT_EXPR_DEPTH: number;
+    LIMIT_COMPOUND_SELECT: number;
+    LIMIT_VDBE_OP: number;
+    LIMIT_FUNCTION_ARG: number;
+    LIMIT_ATTACHED: number;
+    LIMIT_LIKE_PATTERN_LENGTH: number;
+    LIMIT_VARIABLE_NUMBER: number;
+    LIMIT_TRIGGER_DEPTH: number;
+    LIMIT_WORKER_THREADS: number;
+
+    cached: typeof cached;
+    RunResult: RunResult;
+    Statement: typeof Statement;
+    Database: typeof Database;
+    verbose(): this;
+}
\ No newline at end of file
diff --git a/server/node_modules/sqlite3/lib/sqlite3.js b/server/node_modules/sqlite3/lib/sqlite3.js
new file mode 100644
index 0000000..430a2b8
--- /dev/null
+++ b/server/node_modules/sqlite3/lib/sqlite3.js
@@ -0,0 +1,207 @@
+const path = require('path');
+const sqlite3 = require('./sqlite3-binding.js');
+const EventEmitter = require('events').EventEmitter;
+module.exports = exports = sqlite3;
+
+function normalizeMethod (fn) {
+    return function (sql) {
+        let errBack;
+        const args = Array.prototype.slice.call(arguments, 1);
+
+        if (typeof args[args.length - 1] === 'function') {
+            const callback = args[args.length - 1];
+            errBack = function(err) {
+                if (err) {
+                    callback(err);
+                }
+            };
+        }
+        const statement = new Statement(this, sql, errBack);
+        return fn.call(this, statement, args);
+    };
+}
+
+function inherits(target, source) {
+    for (const k in source.prototype)
+        target.prototype[k] = source.prototype[k];
+}
+
+sqlite3.cached = {
+    Database: function(file, a, b) {
+        if (file === '' || file === ':memory:') {
+            // Don't cache special databases.
+            return new Database(file, a, b);
+        }
+
+        let db;
+        file = path.resolve(file);
+
+        if (!sqlite3.cached.objects[file]) {
+            db = sqlite3.cached.objects[file] = new Database(file, a, b);
+        }
+        else {
+            // Make sure the callback is called.
+            db = sqlite3.cached.objects[file];
+            const callback = (typeof a === 'number') ? b : a;
+            if (typeof callback === 'function') {
+                function cb() { callback.call(db, null); }
+                if (db.open) process.nextTick(cb);
+                else db.once('open', cb);
+            }
+        }
+
+        return db;
+    },
+    objects: {}
+};
+
+
+const Database = sqlite3.Database;
+const Statement = sqlite3.Statement;
+const Backup = sqlite3.Backup;
+
+inherits(Database, EventEmitter);
+inherits(Statement, EventEmitter);
+inherits(Backup, EventEmitter);
+
+// Database#prepare(sql, [bind1, bind2, ...], [callback])
+Database.prototype.prepare = normalizeMethod(function(statement, params) {
+    return params.length
+        ? statement.bind.apply(statement, params)
+        : statement;
+});
+
+// Database#run(sql, [bind1, bind2, ...], [callback])
+Database.prototype.run = normalizeMethod(function(statement, params) {
+    statement.run.apply(statement, params).finalize();
+    return this;
+});
+
+// Database#get(sql, [bind1, bind2, ...], [callback])
+Database.prototype.get = normalizeMethod(function(statement, params) {
+    statement.get.apply(statement, params).finalize();
+    return this;
+});
+
+// Database#all(sql, [bind1, bind2, ...], [callback])
+Database.prototype.all = normalizeMethod(function(statement, params) {
+    statement.all.apply(statement, params).finalize();
+    return this;
+});
+
+// Database#each(sql, [bind1, bind2, ...], [callback], [complete])
+Database.prototype.each = normalizeMethod(function(statement, params) {
+    statement.each.apply(statement, params).finalize();
+    return this;
+});
+
+Database.prototype.map = normalizeMethod(function(statement, params) {
+    statement.map.apply(statement, params).finalize();
+    return this;
+});
+
+// Database#backup(filename, [callback])
+// Database#backup(filename, destName, sourceName, filenameIsDest, [callback])
+Database.prototype.backup = function() {
+    let backup;
+    if (arguments.length <= 2) {
+        // By default, we write the main database out to the main database of the named file.
+        // This is the most likely use of the backup api.
+        backup = new Backup(this, arguments[0], 'main', 'main', true, arguments[1]);
+    } else {
+        // Otherwise, give the user full control over the sqlite3_backup_init arguments.
+        backup = new Backup(this, arguments[0], arguments[1], arguments[2], arguments[3], arguments[4]);
+    }
+    // Per the sqlite docs, exclude the following errors as non-fatal by default.
+    backup.retryErrors = [sqlite3.BUSY, sqlite3.LOCKED];
+    return backup;
+};
+
+Statement.prototype.map = function() {
+    const params = Array.prototype.slice.call(arguments);
+    const callback = params.pop();
+    params.push(function(err, rows) {
+        if (err) return callback(err);
+        const result = {};
+        if (rows.length) {
+            const keys = Object.keys(rows[0]);
+            const key = keys[0];
+            if (keys.length > 2) {
+                // Value is an object
+                for (let i = 0; i < rows.length; i++) {
+                    result[rows[i][key]] = rows[i];
+                }
+            } else {
+                const value = keys[1];
+                // Value is a plain value
+                for (let i = 0; i < rows.length; i++) {
+                    result[rows[i][key]] = rows[i][value];
+                }
+            }
+        }
+        callback(err, result);
+    });
+    return this.all.apply(this, params);
+};
+
+let isVerbose = false;
+
+const supportedEvents = [ 'trace', 'profile', 'change' ];
+
+Database.prototype.addListener = Database.prototype.on = function(type) {
+    const val = EventEmitter.prototype.addListener.apply(this, arguments);
+    if (supportedEvents.indexOf(type) >= 0) {
+        this.configure(type, true);
+    }
+    return val;
+};
+
+Database.prototype.removeListener = function(type) {
+    const val = EventEmitter.prototype.removeListener.apply(this, arguments);
+    if (supportedEvents.indexOf(type) >= 0 && !this._events[type]) {
+        this.configure(type, false);
+    }
+    return val;
+};
+
+Database.prototype.removeAllListeners = function(type) {
+    const val = EventEmitter.prototype.removeAllListeners.apply(this, arguments);
+    if (supportedEvents.indexOf(type) >= 0) {
+        this.configure(type, false);
+    }
+    return val;
+};
+
+// Save the stack trace over EIO callbacks.
+sqlite3.verbose = function() {
+    if (!isVerbose) {
+        const trace = require('./trace');
+        [
+            'prepare',
+            'get',
+            'run',
+            'all',
+            'each',
+            'map',
+            'close',
+            'exec'
+        ].forEach(function (name) {
+            trace.extendTrace(Database.prototype, name);
+        });
+        [
+            'bind',
+            'get',
+            'run',
+            'all',
+            'each',
+            'map',
+            'reset',
+            'finalize',
+        ].forEach(function (name) {
+            trace.extendTrace(Statement.prototype, name);
+        });
+        isVerbose = true;
+    }
+
+    return sqlite3;
+};
diff --git a/server/node_modules/sqlite3/lib/trace.js b/server/node_modules/sqlite3/lib/trace.js
new file mode 100644
index 0000000..1d84cb0
--- /dev/null
+++ b/server/node_modules/sqlite3/lib/trace.js
@@ -0,0 +1,38 @@
+// Inspired by https://github.com/tlrobinson/long-stack-traces
+const util = require('util');
+
+function extendTrace(object, property, pos) {
+    const old = object[property];
+    object[property] = function() {
+        const error = new Error();
+        const name = object.constructor.name + '#' + property + '(' +
+            Array.prototype.slice.call(arguments).map(function(el) {
+                return util.inspect(el, false, 0);
+            }).join(', ') + ')';
+
+        if (typeof pos === 'undefined') pos = -1;
+        if (pos < 0) pos += arguments.length;
+        const cb = arguments[pos];
+        if (typeof arguments[pos] === 'function') {
+            arguments[pos] = function replacement() {
+                const err = arguments[0];
+                if (err && err.stack && !err.__augmented) {
+                    err.stack = filter(err).join('\n');
+                    err.stack += '\n--> in ' + name;
+                    err.stack += '\n' + filter(error).slice(1).join('\n');
+                    err.__augmented = true;
+                }
+                return cb.apply(this, arguments);
+            };
+        }
+        return old.apply(this, arguments);
+    };
+}
+exports.extendTrace = extendTrace;
+
+
+function filter(error) {
+    return error.stack.split('\n').filter(function(line) {
+        return line.indexOf(__filename) < 0;
+    });
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/LICENSE.md b/server/node_modules/sqlite3/node_modules/node-addon-api/LICENSE.md
new file mode 100644
index 0000000..819d91a
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/LICENSE.md
@@ -0,0 +1,9 @@
+The MIT License (MIT)
+
+Copyright (c) 2017 [Node.js API collaborators](https://github.com/nodejs/node-addon-api#collaborators)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/README.md b/server/node_modules/sqlite3/node_modules/node-addon-api/README.md
new file mode 100644
index 0000000..e90eb7c
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/README.md
@@ -0,0 +1,319 @@
+NOTE: The default branch has been renamed!
+master is now named main
+
+If you have a local clone, you can update it by running:
+
+```shell
+git branch -m master main
+git fetch origin
+git branch -u origin/main main
+```
+
+# **node-addon-api module**
+This module contains  **header-only C++ wrapper classes** which simplify
+the use of the C based [Node-API](https://nodejs.org/dist/latest/docs/api/n-api.html)
+provided by Node.js when using C++. It provides a C++ object model
+and exception handling semantics with low overhead.
+
+There are three options for implementing addons: Node-API, nan, or direct
+use of internal V8, libuv, and Node.js libraries. Unless there is a need for
+direct access to functionality that is not exposed by Node-API as outlined
+in [C/C++ addons](https://nodejs.org/dist/latest/docs/api/addons.html)
+in Node.js core, use Node-API. Refer to
+[C/C++ addons with Node-API](https://nodejs.org/dist/latest/docs/api/n-api.html)
+for more information on Node-API.
+
+Node-API is an ABI stable C interface provided by Node.js for building native
+addons. It is independent of the underlying JavaScript runtime (e.g. V8 or ChakraCore)
+and is maintained as part of Node.js itself. It is intended to insulate
+native addons from changes in the underlying JavaScript engine and allow
+modules compiled for one version to run on later versions of Node.js without
+recompilation.
+
+The `node-addon-api` module, which is not part of Node.js, preserves the benefits
+of the Node-API as it consists only of inline code that depends only on the stable API
+provided by Node-API. As such, modules built against one version of Node.js
+using node-addon-api should run without having to be rebuilt with newer versions
+of Node.js.
+
+It is important to remember that *other* Node.js interfaces such as
+`libuv` (included in a project via `#include <uv.h>`) are not ABI-stable across
+Node.js major versions. Thus, an addon must use Node-API and/or `node-addon-api`
+exclusively and build against a version of Node.js that includes an
+implementation of Node-API (meaning an active LTS version of Node.js) in
+order to benefit from ABI stability across Node.js major versions. Node.js
+provides an [ABI stability guide][] containing a detailed explanation of ABI
+stability in general, and the Node-API ABI stability guarantee in particular.
+
+As new APIs are added to Node-API, node-addon-api must be updated to provide
+wrappers for those new APIs. For this reason, node-addon-api provides
+methods that allow callers to obtain the underlying Node-API handles so
+direct calls to Node-API and the use of the objects/methods provided by
+node-addon-api can be used together. For example, in order to be able
+to use an API for which the node-addon-api does not yet provide a wrapper.
+
+APIs exposed by node-addon-api are generally used to create and
+manipulate JavaScript values. Concepts and operations generally map
+to ideas specified in the **ECMA262 Language Specification**.
+
+The [Node-API Resource](https://nodejs.github.io/node-addon-examples/) offers an
+excellent orientation and tips for developers just getting started with Node-API
+and node-addon-api.
+
+- **[Setup](#setup)**
+- **[API Documentation](#api)**
+- **[Examples](#examples)**
+- **[Tests](#tests)**
+- **[More resource and info about native Addons](#resources)**
+- **[Badges](#badges)**
+- **[Code of Conduct](CODE_OF_CONDUCT.md)**
+- **[Contributors](#contributors)**
+- **[License](#license)**
+
+## **Current version: 7.1.1**
+
+(See [CHANGELOG.md](CHANGELOG.md) for complete Changelog)
+
+[![NPM](https://nodei.co/npm/node-addon-api.png?downloads=true&downloadRank=true)](https://nodei.co/npm/node-addon-api/) [![NPM](https://nodei.co/npm-dl/node-addon-api.png?months=6&height=1)](https://nodei.co/npm/node-addon-api/)
+
+<a name="setup"></a>
+
+node-addon-api is based on [Node-API](https://nodejs.org/api/n-api.html) and supports using different Node-API versions.
+This allows addons built with it to run with Node.js versions which support the targeted Node-API version.
+**However** the node-addon-api support model is to support only the active LTS Node.js versions. This means that
+every year there will be a new major which drops support for the Node.js LTS version which has gone out of service.
+
+The oldest Node.js version supported by the current version of node-addon-api is Node.js 16.x.
+
+## Setup
+  - [Installation and usage](doc/setup.md)
+  - [node-gyp](doc/node-gyp.md)
+  - [cmake-js](doc/cmake-js.md)
+  - [Conversion tool](doc/conversion-tool.md)
+  - [Checker tool](doc/checker-tool.md)
+  - [Generator](doc/generator.md)
+  - [Prebuild tools](doc/prebuild_tools.md)
+
+<a name="api"></a>
+
+### **API Documentation**
+
+The following is the documentation for node-addon-api.
+
+ - [Full Class Hierarchy](doc/hierarchy.md)
+ - [Addon Structure](doc/addon.md)
+ - Data Types:
+    - [Env](doc/env.md)
+    - [CallbackInfo](doc/callbackinfo.md)
+    - [Reference](doc/reference.md)
+    - [Value](doc/value.md)
+        - [Name](doc/name.md)
+            - [Symbol](doc/symbol.md)
+            - [String](doc/string.md)
+        - [Number](doc/number.md)
+        - [Date](doc/date.md)
+        - [BigInt](doc/bigint.md)
+        - [Boolean](doc/boolean.md)
+        - [External](doc/external.md)
+        - [Object](doc/object.md)
+            - [Array](doc/array.md)
+            - [ObjectReference](doc/object_reference.md)
+    - [PropertyDescriptor](doc/property_descriptor.md)
+    - [Function](doc/function.md)
+        - [FunctionReference](doc/function_reference.md)
+    - [ObjectWrap](doc/object_wrap.md)
+        - [ClassPropertyDescriptor](doc/class_property_descriptor.md)
+    - [Buffer](doc/buffer.md)
+    - [ArrayBuffer](doc/array_buffer.md)
+    - [TypedArray](doc/typed_array.md)
+      - [TypedArrayOf](doc/typed_array_of.md)
+    - [DataView](doc/dataview.md)
+ - [Error Handling](doc/error_handling.md)
+    - [Error](doc/error.md)
+      - [TypeError](doc/type_error.md)
+      - [RangeError](doc/range_error.md)
+      - [SyntaxError](doc/syntax_error.md)
+ - [Object Lifetime Management](doc/object_lifetime_management.md)
+    - [HandleScope](doc/handle_scope.md)
+    - [EscapableHandleScope](doc/escapable_handle_scope.md)
+ - [Memory Management](doc/memory_management.md)
+ - [Async Operations](doc/async_operations.md)
+    - [AsyncWorker](doc/async_worker.md)
+    - [AsyncContext](doc/async_context.md)
+    - [AsyncWorker Variants](doc/async_worker_variants.md)
+ - [Thread-safe Functions](doc/threadsafe.md)
+    - [ThreadSafeFunction](doc/threadsafe_function.md)
+    - [TypedThreadSafeFunction](doc/typed_threadsafe_function.md)
+ - [Promises](doc/promises.md)
+ - [Version management](doc/version_management.md)
+
+<a name="examples"></a>
+
+### **Examples**
+
+Are you new to **node-addon-api**? Take a look at our **[examples](https://github.com/nodejs/node-addon-examples)**
+
+- **[Hello World](https://github.com/nodejs/node-addon-examples/tree/main/src/1-getting-started/1_hello_world)**
+- **[Pass arguments to a function](https://github.com/nodejs/node-addon-examples/tree/main/src/1-getting-started/2_function_arguments/node-addon-api)**
+- **[Callbacks](https://github.com/nodejs/node-addon-examples/tree/main/src/1-getting-started/3_callbacks/node-addon-api)**
+- **[Object factory](https://github.com/nodejs/node-addon-examples/tree/main/src/1-getting-started/4_object_factory/node-addon-api)**
+- **[Function factory](https://github.com/nodejs/node-addon-examples/tree/main/src/1-getting-started/5_function_factory/node-addon-api)**
+- **[Wrapping C++ Object](https://github.com/nodejs/node-addon-examples/tree/main/src/1-getting-started/6_object_wrap/node-addon-api)**
+- **[Factory of wrapped object](https://github.com/nodejs/node-addon-examples/tree/main/src/1-getting-started/7_factory_wrap/node-addon-api)**
+- **[Passing wrapped object around](https://github.com/nodejs/node-addon-examples/tree/main/src/2-js-to-native-conversion/8_passing_wrapped/node-addon-api)**
+
+<a name="tests"></a>
+
+### **Tests**
+
+To run the **node-addon-api** tests do:
+
+```
+npm install
+npm test
+```
+
+To avoid testing the deprecated portions of the API run
+```
+npm install
+npm test --disable-deprecated
+```
+
+To run the tests targeting a specific version of Node-API run
+```
+npm install
+export NAPI_VERSION=X
+npm test --NAPI_VERSION=X
+```
+
+where X is the version of Node-API you want to target.
+
+To run a specific unit test, filter conditions are available
+
+**Example:**
+  compile and run only tests on objectwrap.cc and objectwrap.js
+  ```
+    npm run unit --filter=objectwrap
+  ```
+
+Multiple unit tests cane be selected with wildcards
+
+**Example:**
+compile and run all test files ending with "reference" -> function_reference.cc, object_reference.cc, reference.cc
+ ```
+    npm run unit --filter=*reference
+ ```
+
+Multiple filter conditions can be joined to broaden the test selection
+
+**Example:**
+ compile and run all tests under folders threadsafe_function and typed_threadsafe_function and also the objectwrap.cc file
+    npm run unit --filter='*function objectwrap'
+
+### **Debug**
+
+To run the **node-addon-api** tests with `--debug` option:
+
+```
+npm run-script dev
+```
+
+If you want a faster build, you might use the following option:
+
+```
+npm run-script dev:incremental
+```
+
+Take a look and get inspired by our **[test suite](https://github.com/nodejs/node-addon-api/tree/HEAD/test)**
+
+### **Benchmarks**
+
+You can run the available benchmarks using the following command:
+
+```
+npm run-script benchmark
+```
+
+See [benchmark/README.md](benchmark/README.md) for more details about running and adding benchmarks.
+
+<a name="resources"></a>
+
+### **More resource and info about native Addons**
+- **[C++ Addons](https://nodejs.org/dist/latest/docs/api/addons.html)**
+- **[Node-API](https://nodejs.org/dist/latest/docs/api/n-api.html)**
+- **[Node-API - Next Generation Node API for Native Modules](https://youtu.be/-Oniup60Afs)**
+- **[How We Migrated Realm JavaScript From NAN to Node-API](https://developer.mongodb.com/article/realm-javascript-nan-to-n-api)**
+
+As node-addon-api's core mission is to expose the plain C Node-API as C++
+wrappers, tools that facilitate n-api/node-addon-api providing more
+convenient patterns for developing a Node.js add-on with n-api/node-addon-api
+can be published to NPM as standalone packages. It is also recommended to tag
+such packages with `node-addon-api` to provide more visibility to the community.
+
+Quick links to NPM searches: [keywords:node-addon-api](https://www.npmjs.com/search?q=keywords%3Anode-addon-api).
+
+<a name="other-bindings"></a>
+
+### **Other bindings**
+
+- **[napi-rs](https://napi.rs)** - (`Rust`)
+
+<a name="badges"></a>
+
+### **Badges**
+
+The use of badges is recommended to indicate the minimum version of Node-API
+required for the module. This helps to determine which Node.js major versions are
+supported. Addon maintainers can consult the [Node-API support matrix][] to determine
+which Node.js versions provide a given Node-API version. The following badges are
+available:
+
+![Node-API v1 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v1%20Badge.svg)
+![Node-API v2 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v2%20Badge.svg)
+![Node-API v3 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v3%20Badge.svg)
+![Node-API v4 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v4%20Badge.svg)
+![Node-API v5 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v5%20Badge.svg)
+![Node-API v6 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v6%20Badge.svg)
+![Node-API v7 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v7%20Badge.svg)
+![Node-API v8 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v8%20Badge.svg)
+![Node-API v9 Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20v9%20Badge.svg)
+![Node-API Experimental Version Badge](https://github.com/nodejs/abi-stable-node/blob/doc/assets/Node-API%20Experimental%20Version%20Badge.svg)
+
+## **Contributing**
+
+We love contributions from the community to **node-addon-api**!
+See [CONTRIBUTING.md](CONTRIBUTING.md) for more details on our philosophy around extending this module.
+
+<a name="contributors"></a>
+
+## Team members
+
+### Active
+| Name                | GitHub Link                                           |
+| ------------------- | ----------------------------------------------------- |
+| Anna Henningsen     | [addaleax](https://github.com/addaleax)               |
+| Chengzhong Wu       | [legendecas](https://github.com/legendecas)           |
+| Jack Xia            | [JckXia](https://github.com/JckXia)                   |
+| Kevin Eady          | [KevinEady](https://github.com/KevinEady)             |
+| Michael Dawson      | [mhdawson](https://github.com/mhdawson)               |
+| Nicola Del Gobbo    | [NickNaso](https://github.com/NickNaso)               |
+| Vladimir Morozov    | [vmoroz](https://github.com/vmoroz)                   |
+
+### Emeritus
+| Name                | GitHub Link                                           |
+| ------------------- | ----------------------------------------------------- |
+| Arunesh Chandra     | [aruneshchandra](https://github.com/aruneshchandra)   |
+| Benjamin Byholm     | [kkoopa](https://github.com/kkoopa)                   |
+| Gabriel Schulhof    | [gabrielschulhof](https://github.com/gabrielschulhof) |
+| Hitesh Kanwathirtha | [digitalinfinity](https://github.com/digitalinfinity) |
+| Jason Ginchereau    | [jasongin](https://github.com/jasongin)               |
+| Jim Schlight        | [jschlight](https://github.com/jschlight)             |
+| Sampson Gao         | [sampsongao](https://github.com/sampsongao)           |
+| Taylor Woll         | [boingoing](https://github.com/boingoing)             |
+
+<a name="license"></a>
+
+Licensed under [MIT](./LICENSE.md)
+
+[ABI stability guide]: https://nodejs.org/en/docs/guides/abi-stability/
+[Node-API support matrix]: https://nodejs.org/dist/latest/docs/api/n-api.html#n_api_n_api_version_matrix
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/common.gypi b/server/node_modules/sqlite3/node_modules/node-addon-api/common.gypi
new file mode 100644
index 0000000..06c0176
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/common.gypi
@@ -0,0 +1,20 @@
+{
+  'variables': {
+    'NAPI_VERSION%': "<!(node -p \"process.env.NAPI_VERSION || process.versions.napi\")",
+    'disable_deprecated': "<!(node -p \"process.env['npm_config_disable_deprecated']\")"
+  },
+  'conditions': [
+    ['NAPI_VERSION!=""', { 'defines': ['NAPI_VERSION=<@(NAPI_VERSION)'] } ],
+    ['disable_deprecated=="true"', {
+      'defines': ['NODE_ADDON_API_DISABLE_DEPRECATED']
+    }],
+    ['OS=="mac"', {
+      'cflags+': ['-fvisibility=hidden'],
+      'xcode_settings': {
+        'OTHER_CFLAGS': ['-fvisibility=hidden']
+      }
+    }]
+  ],
+  'cflags': [ '-Werror', '-Wall', '-Wextra', '-Wpedantic', '-Wunused-parameter' ],
+  'cflags_cc': [ '-Werror', '-Wall', '-Wextra', '-Wpedantic', '-Wunused-parameter' ]
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/except.gypi b/server/node_modules/sqlite3/node_modules/node-addon-api/except.gypi
new file mode 100644
index 0000000..e2fb2c5
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/except.gypi
@@ -0,0 +1,25 @@
+{
+  'defines': [ 'NAPI_CPP_EXCEPTIONS' ],
+  'cflags!': [ '-fno-exceptions' ],
+  'cflags_cc!': [ '-fno-exceptions' ],
+  'conditions': [
+    ["OS=='win'", {
+      "defines": [
+        "_HAS_EXCEPTIONS=1"
+      ],
+      "msvs_settings": {
+        "VCCLCompilerTool": {
+          "ExceptionHandling": 1,
+          'EnablePREfast': 'true',
+        },
+      },
+    }],
+    ["OS=='mac'", {
+      'xcode_settings': {
+        'GCC_ENABLE_CPP_EXCEPTIONS': 'YES',
+        'CLANG_CXX_LIBRARY': 'libc++',
+        'MACOSX_DEPLOYMENT_TARGET': '10.7',
+      },
+    }],
+  ],
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/index.js b/server/node_modules/sqlite3/node_modules/node-addon-api/index.js
new file mode 100644
index 0000000..4877abc
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/index.js
@@ -0,0 +1,12 @@
+const path = require('path');
+
+const includeDir = path.relative('.', __dirname);
+
+module.exports = {
+  include: `"${__dirname}"`, // deprecated, can be removed as part of 4.0.0
+  include_dir: includeDir,
+  gyp: path.join(includeDir, 'node_api.gyp:nothing'), // deprecated.
+  targets: path.join(includeDir, 'node_addon_api.gyp'),
+  isNodeApiBuiltin: true,
+  needsFlag: false
+};
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/napi-inl.deprecated.h b/server/node_modules/sqlite3/node_modules/node-addon-api/napi-inl.deprecated.h
new file mode 100644
index 0000000..3ddbb2e
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/napi-inl.deprecated.h
@@ -0,0 +1,186 @@
+#ifndef SRC_NAPI_INL_DEPRECATED_H_
+#define SRC_NAPI_INL_DEPRECATED_H_
+
+////////////////////////////////////////////////////////////////////////////////
+// PropertyDescriptor class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    const char* utf8name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using CbData = details::CallbackData<Getter, Napi::Value>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({getter, nullptr});
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    const std::string& utf8name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor(utf8name.c_str(), getter, attributes, data);
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    napi_value name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using CbData = details::CallbackData<Getter, Napi::Value>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({getter, nullptr});
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Name name, Getter getter, napi_property_attributes attributes, void* data) {
+  napi_value nameValue = name;
+  return PropertyDescriptor::Accessor(nameValue, getter, attributes, data);
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    const char* utf8name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using CbData = details::AccessorCallbackData<Getter, Setter>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({getter, setter, nullptr});
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             CbData::GetterWrapper,
+                             CbData::SetterWrapper,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    const std::string& utf8name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor(utf8name.c_str(), getter, setter, attributes, data);
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    napi_value name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using CbData = details::AccessorCallbackData<Getter, Setter>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({getter, setter, nullptr});
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             CbData::GetterWrapper,
+                             CbData::SetterWrapper,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Name name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  napi_value nameValue = name;
+  return PropertyDescriptor::Accessor(
+      nameValue, getter, setter, attributes, data);
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    const char* utf8name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using ReturnType = decltype(cb(CallbackInfo(nullptr, nullptr)));
+  using CbData = details::CallbackData<Callable, ReturnType>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({cb, nullptr});
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    const std::string& utf8name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* data) {
+  return Function(utf8name.c_str(), cb, attributes, data);
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    napi_value name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* /*data*/) {
+  using ReturnType = decltype(cb(CallbackInfo(nullptr, nullptr)));
+  using CbData = details::CallbackData<Callable, ReturnType>;
+  // TODO: Delete when the function is destroyed
+  auto callbackData = new CbData({cb, nullptr});
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    Name name, Callable cb, napi_property_attributes attributes, void* data) {
+  napi_value nameValue = name;
+  return PropertyDescriptor::Function(nameValue, cb, attributes, data);
+}
+
+#endif  // !SRC_NAPI_INL_DEPRECATED_H_
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/napi-inl.h b/server/node_modules/sqlite3/node_modules/node-addon-api/napi-inl.h
new file mode 100644
index 0000000..a5ae7af
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/napi-inl.h
@@ -0,0 +1,6607 @@
+#ifndef SRC_NAPI_INL_H_
+#define SRC_NAPI_INL_H_
+
+////////////////////////////////////////////////////////////////////////////////
+// Node-API C++ Wrapper Classes
+//
+// Inline header-only implementations for "Node-API" ABI-stable C APIs for
+// Node.js.
+////////////////////////////////////////////////////////////////////////////////
+
+// Note: Do not include this file directly! Include "napi.h" instead.
+
+#include <algorithm>
+#include <cstring>
+#if NAPI_HAS_THREADS
+#include <mutex>
+#endif  // NAPI_HAS_THREADS
+#include <type_traits>
+#include <utility>
+
+namespace Napi {
+
+#ifdef NAPI_CPP_CUSTOM_NAMESPACE
+namespace NAPI_CPP_CUSTOM_NAMESPACE {
+#endif
+
+// Helpers to handle functions exposed from C++ and internal constants.
+namespace details {
+
+// New napi_status constants not yet available in all supported versions of
+// Node.js releases. Only necessary when they are used in napi.h and napi-inl.h.
+constexpr int napi_no_external_buffers_allowed = 22;
+
+template <typename FreeType>
+inline void default_finalizer(napi_env /*env*/, void* data, void* /*hint*/) {
+  delete static_cast<FreeType*>(data);
+}
+
+// Attach a data item to an object and delete it when the object gets
+// garbage-collected.
+// TODO: Replace this code with `napi_add_finalizer()` whenever it becomes
+// available on all supported versions of Node.js.
+template <typename FreeType,
+          napi_finalize finalizer = default_finalizer<FreeType>>
+inline napi_status AttachData(napi_env env,
+                              napi_value obj,
+                              FreeType* data,
+                              void* hint = nullptr) {
+  napi_status status;
+#if (NAPI_VERSION < 5)
+  napi_value symbol, external;
+  status = napi_create_symbol(env, nullptr, &symbol);
+  if (status == napi_ok) {
+    status = napi_create_external(env, data, finalizer, hint, &external);
+    if (status == napi_ok) {
+      napi_property_descriptor desc = {nullptr,
+                                       symbol,
+                                       nullptr,
+                                       nullptr,
+                                       nullptr,
+                                       external,
+                                       napi_default,
+                                       nullptr};
+      status = napi_define_properties(env, obj, 1, &desc);
+    }
+  }
+#else  // NAPI_VERSION >= 5
+  status = napi_add_finalizer(env, obj, data, finalizer, hint, nullptr);
+#endif
+  return status;
+}
+
+// For use in JS to C++ callback wrappers to catch any Napi::Error exceptions
+// and rethrow them as JavaScript exceptions before returning from the callback.
+template <typename Callable>
+inline napi_value WrapCallback(Callable callback) {
+#ifdef NAPI_CPP_EXCEPTIONS
+  try {
+    return callback();
+  } catch (const Error& e) {
+    e.ThrowAsJavaScriptException();
+    return nullptr;
+  }
+#else   // NAPI_CPP_EXCEPTIONS
+  // When C++ exceptions are disabled, errors are immediately thrown as JS
+  // exceptions, so there is no need to catch and rethrow them here.
+  return callback();
+#endif  // NAPI_CPP_EXCEPTIONS
+}
+
+// For use in JS to C++ void callback wrappers to catch any Napi::Error
+// exceptions and rethrow them as JavaScript exceptions before returning from
+// the callback.
+template <typename Callable>
+inline void WrapVoidCallback(Callable callback) {
+#ifdef NAPI_CPP_EXCEPTIONS
+  try {
+    callback();
+  } catch (const Error& e) {
+    e.ThrowAsJavaScriptException();
+  }
+#else   // NAPI_CPP_EXCEPTIONS
+  // When C++ exceptions are disabled, errors are immediately thrown as JS
+  // exceptions, so there is no need to catch and rethrow them here.
+  callback();
+#endif  // NAPI_CPP_EXCEPTIONS
+}
+
+template <typename Callable, typename Return>
+struct CallbackData {
+  static inline napi_value Wrapper(napi_env env, napi_callback_info info) {
+    return details::WrapCallback([&] {
+      CallbackInfo callbackInfo(env, info);
+      CallbackData* callbackData =
+          static_cast<CallbackData*>(callbackInfo.Data());
+      callbackInfo.SetData(callbackData->data);
+      return callbackData->callback(callbackInfo);
+    });
+  }
+
+  Callable callback;
+  void* data;
+};
+
+template <typename Callable>
+struct CallbackData<Callable, void> {
+  static inline napi_value Wrapper(napi_env env, napi_callback_info info) {
+    return details::WrapCallback([&] {
+      CallbackInfo callbackInfo(env, info);
+      CallbackData* callbackData =
+          static_cast<CallbackData*>(callbackInfo.Data());
+      callbackInfo.SetData(callbackData->data);
+      callbackData->callback(callbackInfo);
+      return nullptr;
+    });
+  }
+
+  Callable callback;
+  void* data;
+};
+
+template <void (*Callback)(const CallbackInfo& info)>
+napi_value TemplatedVoidCallback(napi_env env,
+                                 napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback([&] {
+    CallbackInfo cbInfo(env, info);
+    Callback(cbInfo);
+    return nullptr;
+  });
+}
+
+template <Napi::Value (*Callback)(const CallbackInfo& info)>
+napi_value TemplatedCallback(napi_env env,
+                             napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback([&] {
+    CallbackInfo cbInfo(env, info);
+    return Callback(cbInfo);
+  });
+}
+
+template <typename T,
+          Napi::Value (T::*UnwrapCallback)(const CallbackInfo& info)>
+napi_value TemplatedInstanceCallback(napi_env env,
+                                     napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback([&] {
+    CallbackInfo cbInfo(env, info);
+    T* instance = T::Unwrap(cbInfo.This().As<Object>());
+    return instance ? (instance->*UnwrapCallback)(cbInfo) : Napi::Value();
+  });
+}
+
+template <typename T, void (T::*UnwrapCallback)(const CallbackInfo& info)>
+napi_value TemplatedInstanceVoidCallback(napi_env env, napi_callback_info info)
+    NAPI_NOEXCEPT {
+  return details::WrapCallback([&] {
+    CallbackInfo cbInfo(env, info);
+    T* instance = T::Unwrap(cbInfo.This().As<Object>());
+    if (instance) (instance->*UnwrapCallback)(cbInfo);
+    return nullptr;
+  });
+}
+
+template <typename T, typename Finalizer, typename Hint = void>
+struct FinalizeData {
+  static inline void Wrapper(napi_env env,
+                             void* data,
+                             void* finalizeHint) NAPI_NOEXCEPT {
+    WrapVoidCallback([&] {
+      FinalizeData* finalizeData = static_cast<FinalizeData*>(finalizeHint);
+      finalizeData->callback(Env(env), static_cast<T*>(data));
+      delete finalizeData;
+    });
+  }
+
+  static inline void WrapperWithHint(napi_env env,
+                                     void* data,
+                                     void* finalizeHint) NAPI_NOEXCEPT {
+    WrapVoidCallback([&] {
+      FinalizeData* finalizeData = static_cast<FinalizeData*>(finalizeHint);
+      finalizeData->callback(
+          Env(env), static_cast<T*>(data), finalizeData->hint);
+      delete finalizeData;
+    });
+  }
+
+  Finalizer callback;
+  Hint* hint;
+};
+
+#if (NAPI_VERSION > 3 && NAPI_HAS_THREADS)
+template <typename ContextType = void,
+          typename Finalizer = std::function<void(Env, void*, ContextType*)>,
+          typename FinalizerDataType = void>
+struct ThreadSafeFinalize {
+  static inline void Wrapper(napi_env env,
+                             void* rawFinalizeData,
+                             void* /* rawContext */) {
+    if (rawFinalizeData == nullptr) return;
+
+    ThreadSafeFinalize* finalizeData =
+        static_cast<ThreadSafeFinalize*>(rawFinalizeData);
+    finalizeData->callback(Env(env));
+    delete finalizeData;
+  }
+
+  static inline void FinalizeWrapperWithData(napi_env env,
+                                             void* rawFinalizeData,
+                                             void* /* rawContext */) {
+    if (rawFinalizeData == nullptr) return;
+
+    ThreadSafeFinalize* finalizeData =
+        static_cast<ThreadSafeFinalize*>(rawFinalizeData);
+    finalizeData->callback(Env(env), finalizeData->data);
+    delete finalizeData;
+  }
+
+  static inline void FinalizeWrapperWithContext(napi_env env,
+                                                void* rawFinalizeData,
+                                                void* rawContext) {
+    if (rawFinalizeData == nullptr) return;
+
+    ThreadSafeFinalize* finalizeData =
+        static_cast<ThreadSafeFinalize*>(rawFinalizeData);
+    finalizeData->callback(Env(env), static_cast<ContextType*>(rawContext));
+    delete finalizeData;
+  }
+
+  static inline void FinalizeFinalizeWrapperWithDataAndContext(
+      napi_env env, void* rawFinalizeData, void* rawContext) {
+    if (rawFinalizeData == nullptr) return;
+
+    ThreadSafeFinalize* finalizeData =
+        static_cast<ThreadSafeFinalize*>(rawFinalizeData);
+    finalizeData->callback(
+        Env(env), finalizeData->data, static_cast<ContextType*>(rawContext));
+    delete finalizeData;
+  }
+
+  FinalizerDataType* data;
+  Finalizer callback;
+};
+
+template <typename ContextType, typename DataType, typename CallJs, CallJs call>
+inline typename std::enable_if<call != static_cast<CallJs>(nullptr)>::type
+CallJsWrapper(napi_env env, napi_value jsCallback, void* context, void* data) {
+  details::WrapVoidCallback([&]() {
+    call(env,
+         Function(env, jsCallback),
+         static_cast<ContextType*>(context),
+         static_cast<DataType*>(data));
+  });
+}
+
+template <typename ContextType, typename DataType, typename CallJs, CallJs call>
+inline typename std::enable_if<call == static_cast<CallJs>(nullptr)>::type
+CallJsWrapper(napi_env env,
+              napi_value jsCallback,
+              void* /*context*/,
+              void* /*data*/) {
+  details::WrapVoidCallback([&]() {
+    if (jsCallback != nullptr) {
+      Function(env, jsCallback).Call(0, nullptr);
+    }
+  });
+}
+
+#if NAPI_VERSION > 4
+
+template <typename CallbackType, typename TSFN>
+napi_value DefaultCallbackWrapper(napi_env /*env*/, std::nullptr_t /*cb*/) {
+  return nullptr;
+}
+
+template <typename CallbackType, typename TSFN>
+napi_value DefaultCallbackWrapper(napi_env /*env*/, Napi::Function cb) {
+  return cb;
+}
+
+#else
+template <typename CallbackType, typename TSFN>
+napi_value DefaultCallbackWrapper(napi_env env, Napi::Function cb) {
+  if (cb.IsEmpty()) {
+    return TSFN::EmptyFunctionFactory(env);
+  }
+  return cb;
+}
+#endif  // NAPI_VERSION > 4
+#endif  // NAPI_VERSION > 3 && NAPI_HAS_THREADS
+
+template <typename Getter, typename Setter>
+struct AccessorCallbackData {
+  static inline napi_value GetterWrapper(napi_env env,
+                                         napi_callback_info info) {
+    return details::WrapCallback([&] {
+      CallbackInfo callbackInfo(env, info);
+      AccessorCallbackData* callbackData =
+          static_cast<AccessorCallbackData*>(callbackInfo.Data());
+      callbackInfo.SetData(callbackData->data);
+      return callbackData->getterCallback(callbackInfo);
+    });
+  }
+
+  static inline napi_value SetterWrapper(napi_env env,
+                                         napi_callback_info info) {
+    return details::WrapCallback([&] {
+      CallbackInfo callbackInfo(env, info);
+      AccessorCallbackData* callbackData =
+          static_cast<AccessorCallbackData*>(callbackInfo.Data());
+      callbackInfo.SetData(callbackData->data);
+      callbackData->setterCallback(callbackInfo);
+      return nullptr;
+    });
+  }
+
+  Getter getterCallback;
+  Setter setterCallback;
+  void* data;
+};
+
+}  // namespace details
+
+#ifndef NODE_ADDON_API_DISABLE_DEPRECATED
+#include "napi-inl.deprecated.h"
+#endif  // !NODE_ADDON_API_DISABLE_DEPRECATED
+
+////////////////////////////////////////////////////////////////////////////////
+// Module registration
+////////////////////////////////////////////////////////////////////////////////
+
+// Register an add-on based on an initializer function.
+#define NODE_API_MODULE(modname, regfunc)                                      \
+  static napi_value __napi_##regfunc(napi_env env, napi_value exports) {       \
+    return Napi::RegisterModule(env, exports, regfunc);                        \
+  }                                                                            \
+  NAPI_MODULE(modname, __napi_##regfunc)
+
+// Register an add-on based on a subclass of `Addon<T>` with a custom Node.js
+// module name.
+#define NODE_API_NAMED_ADDON(modname, classname)                               \
+  static napi_value __napi_##classname(napi_env env, napi_value exports) {     \
+    return Napi::RegisterModule(env, exports, &classname::Init);               \
+  }                                                                            \
+  NAPI_MODULE(modname, __napi_##classname)
+
+// Register an add-on based on a subclass of `Addon<T>` with the Node.js module
+// name given by node-gyp from the `target_name` in binding.gyp.
+#define NODE_API_ADDON(classname)                                              \
+  NODE_API_NAMED_ADDON(NODE_GYP_MODULE_NAME, classname)
+
+// Adapt the NAPI_MODULE registration function:
+//  - Wrap the arguments in NAPI wrappers.
+//  - Catch any NAPI errors and rethrow as JS exceptions.
+inline napi_value RegisterModule(napi_env env,
+                                 napi_value exports,
+                                 ModuleRegisterCallback registerCallback) {
+  return details::WrapCallback([&] {
+    return napi_value(
+        registerCallback(Napi::Env(env), Napi::Object(env, exports)));
+  });
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Maybe class
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T>
+bool Maybe<T>::IsNothing() const {
+  return !_has_value;
+}
+
+template <class T>
+bool Maybe<T>::IsJust() const {
+  return _has_value;
+}
+
+template <class T>
+void Maybe<T>::Check() const {
+  NAPI_CHECK(IsJust(), "Napi::Maybe::Check", "Maybe value is Nothing.");
+}
+
+template <class T>
+T Maybe<T>::Unwrap() const {
+  NAPI_CHECK(IsJust(), "Napi::Maybe::Unwrap", "Maybe value is Nothing.");
+  return _value;
+}
+
+template <class T>
+T Maybe<T>::UnwrapOr(const T& default_value) const {
+  return _has_value ? _value : default_value;
+}
+
+template <class T>
+bool Maybe<T>::UnwrapTo(T* out) const {
+  if (IsJust()) {
+    *out = _value;
+    return true;
+  };
+  return false;
+}
+
+template <class T>
+bool Maybe<T>::operator==(const Maybe& other) const {
+  return (IsJust() == other.IsJust()) &&
+         (!IsJust() || Unwrap() == other.Unwrap());
+}
+
+template <class T>
+bool Maybe<T>::operator!=(const Maybe& other) const {
+  return !operator==(other);
+}
+
+template <class T>
+Maybe<T>::Maybe() : _has_value(false) {}
+
+template <class T>
+Maybe<T>::Maybe(const T& t) : _has_value(true), _value(t) {}
+
+template <class T>
+inline Maybe<T> Nothing() {
+  return Maybe<T>();
+}
+
+template <class T>
+inline Maybe<T> Just(const T& t) {
+  return Maybe<T>(t);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Env class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Env::Env(napi_env env) : _env(env) {}
+
+inline Env::operator napi_env() const {
+  return _env;
+}
+
+inline Object Env::Global() const {
+  napi_value value;
+  napi_status status = napi_get_global(*this, &value);
+  NAPI_THROW_IF_FAILED(*this, status, Object());
+  return Object(*this, value);
+}
+
+inline Value Env::Undefined() const {
+  napi_value value;
+  napi_status status = napi_get_undefined(*this, &value);
+  NAPI_THROW_IF_FAILED(*this, status, Value());
+  return Value(*this, value);
+}
+
+inline Value Env::Null() const {
+  napi_value value;
+  napi_status status = napi_get_null(*this, &value);
+  NAPI_THROW_IF_FAILED(*this, status, Value());
+  return Value(*this, value);
+}
+
+inline bool Env::IsExceptionPending() const {
+  bool result;
+  napi_status status = napi_is_exception_pending(_env, &result);
+  if (status != napi_ok)
+    result = false;  // Checking for a pending exception shouldn't throw.
+  return result;
+}
+
+inline Error Env::GetAndClearPendingException() const {
+  napi_value value;
+  napi_status status = napi_get_and_clear_last_exception(_env, &value);
+  if (status != napi_ok) {
+    // Don't throw another exception when failing to get the exception!
+    return Error();
+  }
+  return Error(_env, value);
+}
+
+inline MaybeOrValue<Value> Env::RunScript(const char* utf8script) const {
+  String script = String::New(_env, utf8script);
+  return RunScript(script);
+}
+
+inline MaybeOrValue<Value> Env::RunScript(const std::string& utf8script) const {
+  return RunScript(utf8script.c_str());
+}
+
+inline MaybeOrValue<Value> Env::RunScript(String script) const {
+  napi_value result;
+  napi_status status = napi_run_script(_env, script, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Value(_env, result), Napi::Value);
+}
+
+#if NAPI_VERSION > 2
+template <typename Hook, typename Arg>
+void Env::CleanupHook<Hook, Arg>::Wrapper(void* data) NAPI_NOEXCEPT {
+  auto* cleanupData =
+      static_cast<typename Napi::Env::CleanupHook<Hook, Arg>::CleanupData*>(
+          data);
+  cleanupData->hook();
+  delete cleanupData;
+}
+
+template <typename Hook, typename Arg>
+void Env::CleanupHook<Hook, Arg>::WrapperWithArg(void* data) NAPI_NOEXCEPT {
+  auto* cleanupData =
+      static_cast<typename Napi::Env::CleanupHook<Hook, Arg>::CleanupData*>(
+          data);
+  cleanupData->hook(static_cast<Arg*>(cleanupData->arg));
+  delete cleanupData;
+}
+#endif  // NAPI_VERSION > 2
+
+#if NAPI_VERSION > 5
+template <typename T, Env::Finalizer<T> fini>
+inline void Env::SetInstanceData(T* data) const {
+  napi_status status = napi_set_instance_data(
+      _env,
+      data,
+      [](napi_env env, void* data, void*) { fini(env, static_cast<T*>(data)); },
+      nullptr);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+template <typename DataType,
+          typename HintType,
+          Napi::Env::FinalizerWithHint<DataType, HintType> fini>
+inline void Env::SetInstanceData(DataType* data, HintType* hint) const {
+  napi_status status = napi_set_instance_data(
+      _env,
+      data,
+      [](napi_env env, void* data, void* hint) {
+        fini(env, static_cast<DataType*>(data), static_cast<HintType*>(hint));
+      },
+      hint);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+template <typename T>
+inline T* Env::GetInstanceData() const {
+  void* data = nullptr;
+
+  napi_status status = napi_get_instance_data(_env, &data);
+  NAPI_THROW_IF_FAILED(_env, status, nullptr);
+
+  return static_cast<T*>(data);
+}
+
+template <typename T>
+void Env::DefaultFini(Env, T* data) {
+  delete data;
+}
+
+template <typename DataType, typename HintType>
+void Env::DefaultFiniWithHint(Env, DataType* data, HintType*) {
+  delete data;
+}
+#endif  // NAPI_VERSION > 5
+
+#if NAPI_VERSION > 8
+inline const char* Env::GetModuleFileName() const {
+  const char* result;
+  napi_status status = node_api_get_module_file_name(_env, &result);
+  NAPI_THROW_IF_FAILED(*this, status, nullptr);
+  return result;
+}
+#endif  // NAPI_VERSION > 8
+////////////////////////////////////////////////////////////////////////////////
+// Value class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Value::Value() : _env(nullptr), _value(nullptr) {}
+
+inline Value::Value(napi_env env, napi_value value)
+    : _env(env), _value(value) {}
+
+inline Value::operator napi_value() const {
+  return _value;
+}
+
+inline bool Value::operator==(const Value& other) const {
+  return StrictEquals(other);
+}
+
+inline bool Value::operator!=(const Value& other) const {
+  return !this->operator==(other);
+}
+
+inline bool Value::StrictEquals(const Value& other) const {
+  bool result;
+  napi_status status = napi_strict_equals(_env, *this, other, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline Napi::Env Value::Env() const {
+  return Napi::Env(_env);
+}
+
+inline bool Value::IsEmpty() const {
+  return _value == nullptr;
+}
+
+inline napi_valuetype Value::Type() const {
+  if (IsEmpty()) {
+    return napi_undefined;
+  }
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(_env, _value, &type);
+  NAPI_THROW_IF_FAILED(_env, status, napi_undefined);
+  return type;
+}
+
+inline bool Value::IsUndefined() const {
+  return Type() == napi_undefined;
+}
+
+inline bool Value::IsNull() const {
+  return Type() == napi_null;
+}
+
+inline bool Value::IsBoolean() const {
+  return Type() == napi_boolean;
+}
+
+inline bool Value::IsNumber() const {
+  return Type() == napi_number;
+}
+
+#if NAPI_VERSION > 5
+inline bool Value::IsBigInt() const {
+  return Type() == napi_bigint;
+}
+#endif  // NAPI_VERSION > 5
+
+#if (NAPI_VERSION > 4)
+inline bool Value::IsDate() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_date(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+#endif
+
+inline bool Value::IsString() const {
+  return Type() == napi_string;
+}
+
+inline bool Value::IsSymbol() const {
+  return Type() == napi_symbol;
+}
+
+inline bool Value::IsArray() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_array(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsArrayBuffer() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_arraybuffer(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsTypedArray() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_typedarray(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsObject() const {
+  return Type() == napi_object || IsFunction();
+}
+
+inline bool Value::IsFunction() const {
+  return Type() == napi_function;
+}
+
+inline bool Value::IsPromise() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_promise(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsDataView() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_dataview(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsBuffer() const {
+  if (IsEmpty()) {
+    return false;
+  }
+
+  bool result;
+  napi_status status = napi_is_buffer(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+inline bool Value::IsExternal() const {
+  return Type() == napi_external;
+}
+
+template <typename T>
+inline T Value::As() const {
+#ifdef NODE_ADDON_API_ENABLE_TYPE_CHECK_ON_AS
+  T::CheckCast(_env, _value);
+#endif
+  return T(_env, _value);
+}
+
+inline MaybeOrValue<Boolean> Value::ToBoolean() const {
+  napi_value result;
+  napi_status status = napi_coerce_to_bool(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Boolean(_env, result), Napi::Boolean);
+}
+
+inline MaybeOrValue<Number> Value::ToNumber() const {
+  napi_value result;
+  napi_status status = napi_coerce_to_number(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Number(_env, result), Napi::Number);
+}
+
+inline MaybeOrValue<String> Value::ToString() const {
+  napi_value result;
+  napi_status status = napi_coerce_to_string(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::String(_env, result), Napi::String);
+}
+
+inline MaybeOrValue<Object> Value::ToObject() const {
+  napi_value result;
+  napi_status status = napi_coerce_to_object(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Object(_env, result), Napi::Object);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Boolean class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Boolean Boolean::New(napi_env env, bool val) {
+  napi_value value;
+  napi_status status = napi_get_boolean(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, Boolean());
+  return Boolean(env, value);
+}
+
+inline void Boolean::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Boolean::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Boolean::CheckCast", "napi_typeof failed");
+  NAPI_CHECK(
+      type == napi_boolean, "Boolean::CheckCast", "value is not napi_boolean");
+}
+
+inline Boolean::Boolean() : Napi::Value() {}
+
+inline Boolean::Boolean(napi_env env, napi_value value)
+    : Napi::Value(env, value) {}
+
+inline Boolean::operator bool() const {
+  return Value();
+}
+
+inline bool Boolean::Value() const {
+  bool result;
+  napi_status status = napi_get_value_bool(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Number class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Number Number::New(napi_env env, double val) {
+  napi_value value;
+  napi_status status = napi_create_double(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, Number());
+  return Number(env, value);
+}
+
+inline void Number::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Number::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Number::CheckCast", "napi_typeof failed");
+  NAPI_CHECK(
+      type == napi_number, "Number::CheckCast", "value is not napi_number");
+}
+
+inline Number::Number() : Value() {}
+
+inline Number::Number(napi_env env, napi_value value) : Value(env, value) {}
+
+inline Number::operator int32_t() const {
+  return Int32Value();
+}
+
+inline Number::operator uint32_t() const {
+  return Uint32Value();
+}
+
+inline Number::operator int64_t() const {
+  return Int64Value();
+}
+
+inline Number::operator float() const {
+  return FloatValue();
+}
+
+inline Number::operator double() const {
+  return DoubleValue();
+}
+
+inline int32_t Number::Int32Value() const {
+  int32_t result;
+  napi_status status = napi_get_value_int32(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline uint32_t Number::Uint32Value() const {
+  uint32_t result;
+  napi_status status = napi_get_value_uint32(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline int64_t Number::Int64Value() const {
+  int64_t result;
+  napi_status status = napi_get_value_int64(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline float Number::FloatValue() const {
+  return static_cast<float>(DoubleValue());
+}
+
+inline double Number::DoubleValue() const {
+  double result;
+  napi_status status = napi_get_value_double(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+#if NAPI_VERSION > 5
+////////////////////////////////////////////////////////////////////////////////
+// BigInt Class
+////////////////////////////////////////////////////////////////////////////////
+
+inline BigInt BigInt::New(napi_env env, int64_t val) {
+  napi_value value;
+  napi_status status = napi_create_bigint_int64(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, BigInt());
+  return BigInt(env, value);
+}
+
+inline BigInt BigInt::New(napi_env env, uint64_t val) {
+  napi_value value;
+  napi_status status = napi_create_bigint_uint64(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, BigInt());
+  return BigInt(env, value);
+}
+
+inline BigInt BigInt::New(napi_env env,
+                          int sign_bit,
+                          size_t word_count,
+                          const uint64_t* words) {
+  napi_value value;
+  napi_status status =
+      napi_create_bigint_words(env, sign_bit, word_count, words, &value);
+  NAPI_THROW_IF_FAILED(env, status, BigInt());
+  return BigInt(env, value);
+}
+
+inline void BigInt::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "BigInt::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "BigInt::CheckCast", "napi_typeof failed");
+  NAPI_CHECK(
+      type == napi_bigint, "BigInt::CheckCast", "value is not napi_bigint");
+}
+
+inline BigInt::BigInt() : Value() {}
+
+inline BigInt::BigInt(napi_env env, napi_value value) : Value(env, value) {}
+
+inline int64_t BigInt::Int64Value(bool* lossless) const {
+  int64_t result;
+  napi_status status =
+      napi_get_value_bigint_int64(_env, _value, &result, lossless);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline uint64_t BigInt::Uint64Value(bool* lossless) const {
+  uint64_t result;
+  napi_status status =
+      napi_get_value_bigint_uint64(_env, _value, &result, lossless);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+inline size_t BigInt::WordCount() const {
+  size_t word_count;
+  napi_status status =
+      napi_get_value_bigint_words(_env, _value, nullptr, &word_count, nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return word_count;
+}
+
+inline void BigInt::ToWords(int* sign_bit,
+                            size_t* word_count,
+                            uint64_t* words) {
+  napi_status status =
+      napi_get_value_bigint_words(_env, _value, sign_bit, word_count, words);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+#endif  // NAPI_VERSION > 5
+
+#if (NAPI_VERSION > 4)
+////////////////////////////////////////////////////////////////////////////////
+// Date Class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Date Date::New(napi_env env, double val) {
+  napi_value value;
+  napi_status status = napi_create_date(env, val, &value);
+  NAPI_THROW_IF_FAILED(env, status, Date());
+  return Date(env, value);
+}
+
+inline void Date::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Date::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_date(env, value, &result);
+  NAPI_CHECK(status == napi_ok, "Date::CheckCast", "napi_is_date failed");
+  NAPI_CHECK(result, "Date::CheckCast", "value is not date");
+}
+
+inline Date::Date() : Value() {}
+
+inline Date::Date(napi_env env, napi_value value) : Value(env, value) {}
+
+inline Date::operator double() const {
+  return ValueOf();
+}
+
+inline double Date::ValueOf() const {
+  double result;
+  napi_status status = napi_get_date_value(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// Name class
+////////////////////////////////////////////////////////////////////////////////
+inline void Name::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Name::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Name::CheckCast", "napi_typeof failed");
+  NAPI_CHECK(type == napi_string || type == napi_symbol,
+             "Name::CheckCast",
+             "value is not napi_string or napi_symbol");
+}
+
+inline Name::Name() : Value() {}
+
+inline Name::Name(napi_env env, napi_value value) : Value(env, value) {}
+
+////////////////////////////////////////////////////////////////////////////////
+// String class
+////////////////////////////////////////////////////////////////////////////////
+
+inline String String::New(napi_env env, const std::string& val) {
+  return String::New(env, val.c_str(), val.size());
+}
+
+inline String String::New(napi_env env, const std::u16string& val) {
+  return String::New(env, val.c_str(), val.size());
+}
+
+inline String String::New(napi_env env, const char* val) {
+  // TODO(@gabrielschulhof) Remove if-statement when core's error handling is
+  // available in all supported versions.
+  if (val == nullptr) {
+    // Throw an error that looks like it came from core.
+    NAPI_THROW_IF_FAILED(env, napi_invalid_arg, String());
+  }
+  napi_value value;
+  napi_status status =
+      napi_create_string_utf8(env, val, std::strlen(val), &value);
+  NAPI_THROW_IF_FAILED(env, status, String());
+  return String(env, value);
+}
+
+inline String String::New(napi_env env, const char16_t* val) {
+  napi_value value;
+  // TODO(@gabrielschulhof) Remove if-statement when core's error handling is
+  // available in all supported versions.
+  if (val == nullptr) {
+    // Throw an error that looks like it came from core.
+    NAPI_THROW_IF_FAILED(env, napi_invalid_arg, String());
+  }
+  napi_status status =
+      napi_create_string_utf16(env, val, std::u16string(val).size(), &value);
+  NAPI_THROW_IF_FAILED(env, status, String());
+  return String(env, value);
+}
+
+inline String String::New(napi_env env, const char* val, size_t length) {
+  napi_value value;
+  napi_status status = napi_create_string_utf8(env, val, length, &value);
+  NAPI_THROW_IF_FAILED(env, status, String());
+  return String(env, value);
+}
+
+inline String String::New(napi_env env, const char16_t* val, size_t length) {
+  napi_value value;
+  napi_status status = napi_create_string_utf16(env, val, length, &value);
+  NAPI_THROW_IF_FAILED(env, status, String());
+  return String(env, value);
+}
+
+inline void String::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "String::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "String::CheckCast", "napi_typeof failed");
+  NAPI_CHECK(
+      type == napi_string, "String::CheckCast", "value is not napi_string");
+}
+
+inline String::String() : Name() {}
+
+inline String::String(napi_env env, napi_value value) : Name(env, value) {}
+
+inline String::operator std::string() const {
+  return Utf8Value();
+}
+
+inline String::operator std::u16string() const {
+  return Utf16Value();
+}
+
+inline std::string String::Utf8Value() const {
+  size_t length;
+  napi_status status =
+      napi_get_value_string_utf8(_env, _value, nullptr, 0, &length);
+  NAPI_THROW_IF_FAILED(_env, status, "");
+
+  std::string value;
+  value.reserve(length + 1);
+  value.resize(length);
+  status = napi_get_value_string_utf8(
+      _env, _value, &value[0], value.capacity(), nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, "");
+  return value;
+}
+
+inline std::u16string String::Utf16Value() const {
+  size_t length;
+  napi_status status =
+      napi_get_value_string_utf16(_env, _value, nullptr, 0, &length);
+  NAPI_THROW_IF_FAILED(_env, status, NAPI_WIDE_TEXT(""));
+
+  std::u16string value;
+  value.reserve(length + 1);
+  value.resize(length);
+  status = napi_get_value_string_utf16(
+      _env, _value, &value[0], value.capacity(), nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, NAPI_WIDE_TEXT(""));
+  return value;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Symbol class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Symbol Symbol::New(napi_env env, const char* description) {
+  napi_value descriptionValue = description != nullptr
+                                    ? String::New(env, description)
+                                    : static_cast<napi_value>(nullptr);
+  return Symbol::New(env, descriptionValue);
+}
+
+inline Symbol Symbol::New(napi_env env, const std::string& description) {
+  napi_value descriptionValue = String::New(env, description);
+  return Symbol::New(env, descriptionValue);
+}
+
+inline Symbol Symbol::New(napi_env env, String description) {
+  napi_value descriptionValue = description;
+  return Symbol::New(env, descriptionValue);
+}
+
+inline Symbol Symbol::New(napi_env env, napi_value description) {
+  napi_value value;
+  napi_status status = napi_create_symbol(env, description, &value);
+  NAPI_THROW_IF_FAILED(env, status, Symbol());
+  return Symbol(env, value);
+}
+
+inline MaybeOrValue<Symbol> Symbol::WellKnown(napi_env env,
+                                              const std::string& name) {
+#if defined(NODE_ADDON_API_ENABLE_MAYBE)
+  Value symbol_obj;
+  Value symbol_value;
+  if (Napi::Env(env).Global().Get("Symbol").UnwrapTo(&symbol_obj) &&
+      symbol_obj.As<Object>().Get(name).UnwrapTo(&symbol_value)) {
+    return Just<Symbol>(symbol_value.As<Symbol>());
+  }
+  return Nothing<Symbol>();
+#else
+  return Napi::Env(env)
+      .Global()
+      .Get("Symbol")
+      .As<Object>()
+      .Get(name)
+      .As<Symbol>();
+#endif
+}
+
+inline MaybeOrValue<Symbol> Symbol::For(napi_env env,
+                                        const std::string& description) {
+  napi_value descriptionValue = String::New(env, description);
+  return Symbol::For(env, descriptionValue);
+}
+
+inline MaybeOrValue<Symbol> Symbol::For(napi_env env, const char* description) {
+  napi_value descriptionValue = String::New(env, description);
+  return Symbol::For(env, descriptionValue);
+}
+
+inline MaybeOrValue<Symbol> Symbol::For(napi_env env, String description) {
+  return Symbol::For(env, static_cast<napi_value>(description));
+}
+
+inline MaybeOrValue<Symbol> Symbol::For(napi_env env, napi_value description) {
+#if defined(NODE_ADDON_API_ENABLE_MAYBE)
+  Value symbol_obj;
+  Value symbol_for_value;
+  Value symbol_value;
+  if (Napi::Env(env).Global().Get("Symbol").UnwrapTo(&symbol_obj) &&
+      symbol_obj.As<Object>().Get("for").UnwrapTo(&symbol_for_value) &&
+      symbol_for_value.As<Function>()
+          .Call(symbol_obj, {description})
+          .UnwrapTo(&symbol_value)) {
+    return Just<Symbol>(symbol_value.As<Symbol>());
+  }
+  return Nothing<Symbol>();
+#else
+  Object symbol_obj = Napi::Env(env).Global().Get("Symbol").As<Object>();
+  return symbol_obj.Get("for")
+      .As<Function>()
+      .Call(symbol_obj, {description})
+      .As<Symbol>();
+#endif
+}
+
+inline void Symbol::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Symbol::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Symbol::CheckCast", "napi_typeof failed");
+  NAPI_CHECK(
+      type == napi_symbol, "Symbol::CheckCast", "value is not napi_symbol");
+}
+
+inline Symbol::Symbol() : Name() {}
+
+inline Symbol::Symbol(napi_env env, napi_value value) : Name(env, value) {}
+
+////////////////////////////////////////////////////////////////////////////////
+// Automagic value creation
+////////////////////////////////////////////////////////////////////////////////
+
+namespace details {
+template <typename T>
+struct vf_number {
+  static Number From(napi_env env, T value) {
+    return Number::New(env, static_cast<double>(value));
+  }
+};
+
+template <>
+struct vf_number<bool> {
+  static Boolean From(napi_env env, bool value) {
+    return Boolean::New(env, value);
+  }
+};
+
+struct vf_utf8_charp {
+  static String From(napi_env env, const char* value) {
+    return String::New(env, value);
+  }
+};
+
+struct vf_utf16_charp {
+  static String From(napi_env env, const char16_t* value) {
+    return String::New(env, value);
+  }
+};
+struct vf_utf8_string {
+  static String From(napi_env env, const std::string& value) {
+    return String::New(env, value);
+  }
+};
+
+struct vf_utf16_string {
+  static String From(napi_env env, const std::u16string& value) {
+    return String::New(env, value);
+  }
+};
+
+template <typename T>
+struct vf_fallback {
+  static Value From(napi_env env, const T& value) { return Value(env, value); }
+};
+
+template <typename...>
+struct disjunction : std::false_type {};
+template <typename B>
+struct disjunction<B> : B {};
+template <typename B, typename... Bs>
+struct disjunction<B, Bs...>
+    : std::conditional<bool(B::value), B, disjunction<Bs...>>::type {};
+
+template <typename T>
+struct can_make_string
+    : disjunction<typename std::is_convertible<T, const char*>::type,
+                  typename std::is_convertible<T, const char16_t*>::type,
+                  typename std::is_convertible<T, std::string>::type,
+                  typename std::is_convertible<T, std::u16string>::type> {};
+}  // namespace details
+
+template <typename T>
+Value Value::From(napi_env env, const T& value) {
+  using Helper = typename std::conditional<
+      std::is_integral<T>::value || std::is_floating_point<T>::value,
+      details::vf_number<T>,
+      typename std::conditional<details::can_make_string<T>::value,
+                                String,
+                                details::vf_fallback<T>>::type>::type;
+  return Helper::From(env, value);
+}
+
+template <typename T>
+String String::From(napi_env env, const T& value) {
+  struct Dummy {};
+  using Helper = typename std::conditional<
+      std::is_convertible<T, const char*>::value,
+      details::vf_utf8_charp,
+      typename std::conditional<
+          std::is_convertible<T, const char16_t*>::value,
+          details::vf_utf16_charp,
+          typename std::conditional<
+              std::is_convertible<T, std::string>::value,
+              details::vf_utf8_string,
+              typename std::conditional<
+                  std::is_convertible<T, std::u16string>::value,
+                  details::vf_utf16_string,
+                  Dummy>::type>::type>::type>::type;
+  return Helper::From(env, value);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TypeTaggable class
+////////////////////////////////////////////////////////////////////////////////
+
+inline TypeTaggable::TypeTaggable() : Value() {}
+
+inline TypeTaggable::TypeTaggable(napi_env _env, napi_value _value)
+    : Value(_env, _value) {}
+
+#if NAPI_VERSION >= 8
+
+inline void TypeTaggable::TypeTag(const napi_type_tag* type_tag) const {
+  napi_status status = napi_type_tag_object(_env, _value, type_tag);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline bool TypeTaggable::CheckTypeTag(const napi_type_tag* type_tag) const {
+  bool result;
+  napi_status status =
+      napi_check_object_type_tag(_env, _value, type_tag, &result);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return result;
+}
+
+#endif  // NAPI_VERSION >= 8
+
+////////////////////////////////////////////////////////////////////////////////
+// Object class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename Key>
+inline Object::PropertyLValue<Key>::operator Value() const {
+  MaybeOrValue<Value> val = Object(_env, _object).Get(_key);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  return val.Unwrap();
+#else
+  return val;
+#endif
+}
+
+template <typename Key>
+template <typename ValueType>
+inline Object::PropertyLValue<Key>& Object::PropertyLValue<Key>::operator=(
+    ValueType value) {
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  MaybeOrValue<bool> result =
+#endif
+      Object(_env, _object).Set(_key, value);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  result.Unwrap();
+#endif
+  return *this;
+}
+
+template <typename Key>
+inline Object::PropertyLValue<Key>::PropertyLValue(Object object, Key key)
+    : _env(object.Env()), _object(object), _key(key) {}
+
+inline Object Object::New(napi_env env) {
+  napi_value value;
+  napi_status status = napi_create_object(env, &value);
+  NAPI_THROW_IF_FAILED(env, status, Object());
+  return Object(env, value);
+}
+
+inline void Object::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Object::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Object::CheckCast", "napi_typeof failed");
+  NAPI_CHECK(
+      type == napi_object, "Object::CheckCast", "value is not napi_object");
+}
+
+inline Object::Object() : TypeTaggable() {}
+
+inline Object::Object(napi_env env, napi_value value)
+    : TypeTaggable(env, value) {}
+
+inline Object::PropertyLValue<std::string> Object::operator[](
+    const char* utf8name) {
+  return PropertyLValue<std::string>(*this, utf8name);
+}
+
+inline Object::PropertyLValue<std::string> Object::operator[](
+    const std::string& utf8name) {
+  return PropertyLValue<std::string>(*this, utf8name);
+}
+
+inline Object::PropertyLValue<uint32_t> Object::operator[](uint32_t index) {
+  return PropertyLValue<uint32_t>(*this, index);
+}
+
+inline Object::PropertyLValue<Value> Object::operator[](Value index) const {
+  return PropertyLValue<Value>(*this, index);
+}
+
+inline MaybeOrValue<Value> Object::operator[](const char* utf8name) const {
+  return Get(utf8name);
+}
+
+inline MaybeOrValue<Value> Object::operator[](
+    const std::string& utf8name) const {
+  return Get(utf8name);
+}
+
+inline MaybeOrValue<Value> Object::operator[](uint32_t index) const {
+  return Get(index);
+}
+
+inline MaybeOrValue<bool> Object::Has(napi_value key) const {
+  bool result;
+  napi_status status = napi_has_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Has(Value key) const {
+  bool result;
+  napi_status status = napi_has_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Has(const char* utf8name) const {
+  bool result;
+  napi_status status = napi_has_named_property(_env, _value, utf8name, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Has(const std::string& utf8name) const {
+  return Has(utf8name.c_str());
+}
+
+inline MaybeOrValue<bool> Object::HasOwnProperty(napi_value key) const {
+  bool result;
+  napi_status status = napi_has_own_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::HasOwnProperty(Value key) const {
+  bool result;
+  napi_status status = napi_has_own_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::HasOwnProperty(const char* utf8name) const {
+  napi_value key;
+  napi_status status =
+      napi_create_string_utf8(_env, utf8name, std::strlen(utf8name), &key);
+  NAPI_MAYBE_THROW_IF_FAILED(_env, status, bool);
+  return HasOwnProperty(key);
+}
+
+inline MaybeOrValue<bool> Object::HasOwnProperty(
+    const std::string& utf8name) const {
+  return HasOwnProperty(utf8name.c_str());
+}
+
+inline MaybeOrValue<Value> Object::Get(napi_value key) const {
+  napi_value result;
+  napi_status status = napi_get_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Value(_env, result), Value);
+}
+
+inline MaybeOrValue<Value> Object::Get(Value key) const {
+  napi_value result;
+  napi_status status = napi_get_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Value(_env, result), Value);
+}
+
+inline MaybeOrValue<Value> Object::Get(const char* utf8name) const {
+  napi_value result;
+  napi_status status = napi_get_named_property(_env, _value, utf8name, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Value(_env, result), Value);
+}
+
+inline MaybeOrValue<Value> Object::Get(const std::string& utf8name) const {
+  return Get(utf8name.c_str());
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(napi_value key,
+                                      const ValueType& value) const {
+  napi_status status =
+      napi_set_property(_env, _value, key, Value::From(_env, value));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(Value key, const ValueType& value) const {
+  napi_status status =
+      napi_set_property(_env, _value, key, Value::From(_env, value));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(const char* utf8name,
+                                      const ValueType& value) const {
+  napi_status status =
+      napi_set_named_property(_env, _value, utf8name, Value::From(_env, value));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(const std::string& utf8name,
+                                      const ValueType& value) const {
+  return Set(utf8name.c_str(), value);
+}
+
+inline MaybeOrValue<bool> Object::Delete(napi_value key) const {
+  bool result;
+  napi_status status = napi_delete_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Delete(Value key) const {
+  bool result;
+  napi_status status = napi_delete_property(_env, _value, key, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<bool> Object::Delete(const char* utf8name) const {
+  return Delete(String::New(_env, utf8name));
+}
+
+inline MaybeOrValue<bool> Object::Delete(const std::string& utf8name) const {
+  return Delete(String::New(_env, utf8name));
+}
+
+inline MaybeOrValue<bool> Object::Has(uint32_t index) const {
+  bool result;
+  napi_status status = napi_has_element(_env, _value, index, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<Value> Object::Get(uint32_t index) const {
+  napi_value value;
+  napi_status status = napi_get_element(_env, _value, index, &value);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Value(_env, value), Value);
+}
+
+template <typename ValueType>
+inline MaybeOrValue<bool> Object::Set(uint32_t index,
+                                      const ValueType& value) const {
+  napi_status status =
+      napi_set_element(_env, _value, index, Value::From(_env, value));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::Delete(uint32_t index) const {
+  bool result;
+  napi_status status = napi_delete_element(_env, _value, index, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+inline MaybeOrValue<Array> Object::GetPropertyNames() const {
+  napi_value result;
+  napi_status status = napi_get_property_names(_env, _value, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, Array(_env, result), Array);
+}
+
+inline MaybeOrValue<bool> Object::DefineProperty(
+    const PropertyDescriptor& property) const {
+  napi_status status = napi_define_properties(
+      _env,
+      _value,
+      1,
+      reinterpret_cast<const napi_property_descriptor*>(&property));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::DefineProperties(
+    const std::initializer_list<PropertyDescriptor>& properties) const {
+  napi_status status = napi_define_properties(
+      _env,
+      _value,
+      properties.size(),
+      reinterpret_cast<const napi_property_descriptor*>(properties.begin()));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::DefineProperties(
+    const std::vector<PropertyDescriptor>& properties) const {
+  napi_status status = napi_define_properties(
+      _env,
+      _value,
+      properties.size(),
+      reinterpret_cast<const napi_property_descriptor*>(properties.data()));
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::InstanceOf(
+    const Function& constructor) const {
+  bool result;
+  napi_status status = napi_instanceof(_env, _value, constructor, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, result, bool);
+}
+
+template <typename Finalizer, typename T>
+inline void Object::AddFinalizer(Finalizer finalizeCallback, T* data) const {
+  details::FinalizeData<T, Finalizer>* finalizeData =
+      new details::FinalizeData<T, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+  napi_status status =
+      details::AttachData<T, details::FinalizeData<T, Finalizer>::Wrapper>(
+          _env, *this, data, finalizeData);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+template <typename Finalizer, typename T, typename Hint>
+inline void Object::AddFinalizer(Finalizer finalizeCallback,
+                                 T* data,
+                                 Hint* finalizeHint) const {
+  details::FinalizeData<T, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<T, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+  napi_status status = details::
+      AttachData<T, details::FinalizeData<T, Finalizer, Hint>::WrapperWithHint>(
+          _env, *this, data, finalizeData);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+#ifdef NAPI_CPP_EXCEPTIONS
+inline Object::const_iterator::const_iterator(const Object* object,
+                                              const Type type) {
+  _object = object;
+  _keys = object->GetPropertyNames();
+  _index = type == Type::BEGIN ? 0 : _keys.Length();
+}
+
+inline Object::const_iterator Napi::Object::begin() const {
+  const_iterator it(this, Object::const_iterator::Type::BEGIN);
+  return it;
+}
+
+inline Object::const_iterator Napi::Object::end() const {
+  const_iterator it(this, Object::const_iterator::Type::END);
+  return it;
+}
+
+inline Object::const_iterator& Object::const_iterator::operator++() {
+  ++_index;
+  return *this;
+}
+
+inline bool Object::const_iterator::operator==(
+    const const_iterator& other) const {
+  return _index == other._index;
+}
+
+inline bool Object::const_iterator::operator!=(
+    const const_iterator& other) const {
+  return _index != other._index;
+}
+
+inline const std::pair<Value, Object::PropertyLValue<Value>>
+Object::const_iterator::operator*() const {
+  const Value key = _keys[_index];
+  const PropertyLValue<Value> value = (*_object)[key];
+  return {key, value};
+}
+
+inline Object::iterator::iterator(Object* object, const Type type) {
+  _object = object;
+  _keys = object->GetPropertyNames();
+  _index = type == Type::BEGIN ? 0 : _keys.Length();
+}
+
+inline Object::iterator Napi::Object::begin() {
+  iterator it(this, Object::iterator::Type::BEGIN);
+  return it;
+}
+
+inline Object::iterator Napi::Object::end() {
+  iterator it(this, Object::iterator::Type::END);
+  return it;
+}
+
+inline Object::iterator& Object::iterator::operator++() {
+  ++_index;
+  return *this;
+}
+
+inline bool Object::iterator::operator==(const iterator& other) const {
+  return _index == other._index;
+}
+
+inline bool Object::iterator::operator!=(const iterator& other) const {
+  return _index != other._index;
+}
+
+inline std::pair<Value, Object::PropertyLValue<Value>>
+Object::iterator::operator*() {
+  Value key = _keys[_index];
+  PropertyLValue<Value> value = (*_object)[key];
+  return {key, value};
+}
+#endif  // NAPI_CPP_EXCEPTIONS
+
+#if NAPI_VERSION >= 8
+inline MaybeOrValue<bool> Object::Freeze() const {
+  napi_status status = napi_object_freeze(_env, _value);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+
+inline MaybeOrValue<bool> Object::Seal() const {
+  napi_status status = napi_object_seal(_env, _value);
+  NAPI_RETURN_OR_THROW_IF_FAILED(_env, status, status == napi_ok, bool);
+}
+#endif  // NAPI_VERSION >= 8
+
+////////////////////////////////////////////////////////////////////////////////
+// External class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline External<T> External<T>::New(napi_env env, T* data) {
+  napi_value value;
+  napi_status status =
+      napi_create_external(env, data, nullptr, nullptr, &value);
+  NAPI_THROW_IF_FAILED(env, status, External());
+  return External(env, value);
+}
+
+template <typename T>
+template <typename Finalizer>
+inline External<T> External<T>::New(napi_env env,
+                                    T* data,
+                                    Finalizer finalizeCallback) {
+  napi_value value;
+  details::FinalizeData<T, Finalizer>* finalizeData =
+      new details::FinalizeData<T, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+  napi_status status =
+      napi_create_external(env,
+                           data,
+                           details::FinalizeData<T, Finalizer>::Wrapper,
+                           finalizeData,
+                           &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, External());
+  }
+  return External(env, value);
+}
+
+template <typename T>
+template <typename Finalizer, typename Hint>
+inline External<T> External<T>::New(napi_env env,
+                                    T* data,
+                                    Finalizer finalizeCallback,
+                                    Hint* finalizeHint) {
+  napi_value value;
+  details::FinalizeData<T, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<T, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+  napi_status status = napi_create_external(
+      env,
+      data,
+      details::FinalizeData<T, Finalizer, Hint>::WrapperWithHint,
+      finalizeData,
+      &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, External());
+  }
+  return External(env, value);
+}
+
+template <typename T>
+inline void External<T>::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "External::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "External::CheckCast", "napi_typeof failed");
+  NAPI_CHECK(type == napi_external,
+             "External::CheckCast",
+             "value is not napi_external");
+}
+
+template <typename T>
+inline External<T>::External() : TypeTaggable() {}
+
+template <typename T>
+inline External<T>::External(napi_env env, napi_value value)
+    : TypeTaggable(env, value) {}
+
+template <typename T>
+inline T* External<T>::Data() const {
+  void* data;
+  napi_status status = napi_get_value_external(_env, _value, &data);
+  NAPI_THROW_IF_FAILED(_env, status, nullptr);
+  return reinterpret_cast<T*>(data);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Array class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Array Array::New(napi_env env) {
+  napi_value value;
+  napi_status status = napi_create_array(env, &value);
+  NAPI_THROW_IF_FAILED(env, status, Array());
+  return Array(env, value);
+}
+
+inline Array Array::New(napi_env env, size_t length) {
+  napi_value value;
+  napi_status status = napi_create_array_with_length(env, length, &value);
+  NAPI_THROW_IF_FAILED(env, status, Array());
+  return Array(env, value);
+}
+
+inline void Array::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Array::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_array(env, value, &result);
+  NAPI_CHECK(status == napi_ok, "Array::CheckCast", "napi_is_array failed");
+  NAPI_CHECK(result, "Array::CheckCast", "value is not array");
+}
+
+inline Array::Array() : Object() {}
+
+inline Array::Array(napi_env env, napi_value value) : Object(env, value) {}
+
+inline uint32_t Array::Length() const {
+  uint32_t result;
+  napi_status status = napi_get_array_length(_env, _value, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ArrayBuffer class
+////////////////////////////////////////////////////////////////////////////////
+
+inline ArrayBuffer ArrayBuffer::New(napi_env env, size_t byteLength) {
+  napi_value value;
+  void* data;
+  napi_status status = napi_create_arraybuffer(env, byteLength, &data, &value);
+  NAPI_THROW_IF_FAILED(env, status, ArrayBuffer());
+
+  return ArrayBuffer(env, value);
+}
+
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+inline ArrayBuffer ArrayBuffer::New(napi_env env,
+                                    void* externalData,
+                                    size_t byteLength) {
+  napi_value value;
+  napi_status status = napi_create_external_arraybuffer(
+      env, externalData, byteLength, nullptr, nullptr, &value);
+  NAPI_THROW_IF_FAILED(env, status, ArrayBuffer());
+
+  return ArrayBuffer(env, value);
+}
+
+template <typename Finalizer>
+inline ArrayBuffer ArrayBuffer::New(napi_env env,
+                                    void* externalData,
+                                    size_t byteLength,
+                                    Finalizer finalizeCallback) {
+  napi_value value;
+  details::FinalizeData<void, Finalizer>* finalizeData =
+      new details::FinalizeData<void, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+  napi_status status = napi_create_external_arraybuffer(
+      env,
+      externalData,
+      byteLength,
+      details::FinalizeData<void, Finalizer>::Wrapper,
+      finalizeData,
+      &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, ArrayBuffer());
+  }
+
+  return ArrayBuffer(env, value);
+}
+
+template <typename Finalizer, typename Hint>
+inline ArrayBuffer ArrayBuffer::New(napi_env env,
+                                    void* externalData,
+                                    size_t byteLength,
+                                    Finalizer finalizeCallback,
+                                    Hint* finalizeHint) {
+  napi_value value;
+  details::FinalizeData<void, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<void, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+  napi_status status = napi_create_external_arraybuffer(
+      env,
+      externalData,
+      byteLength,
+      details::FinalizeData<void, Finalizer, Hint>::WrapperWithHint,
+      finalizeData,
+      &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, ArrayBuffer());
+  }
+
+  return ArrayBuffer(env, value);
+}
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+
+inline void ArrayBuffer::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "ArrayBuffer::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_arraybuffer(env, value, &result);
+  NAPI_CHECK(status == napi_ok,
+             "ArrayBuffer::CheckCast",
+             "napi_is_arraybuffer failed");
+  NAPI_CHECK(result, "ArrayBuffer::CheckCast", "value is not arraybuffer");
+}
+
+inline ArrayBuffer::ArrayBuffer() : Object() {}
+
+inline ArrayBuffer::ArrayBuffer(napi_env env, napi_value value)
+    : Object(env, value) {}
+
+inline void* ArrayBuffer::Data() {
+  void* data;
+  napi_status status = napi_get_arraybuffer_info(_env, _value, &data, nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, nullptr);
+  return data;
+}
+
+inline size_t ArrayBuffer::ByteLength() {
+  size_t length;
+  napi_status status =
+      napi_get_arraybuffer_info(_env, _value, nullptr, &length);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return length;
+}
+
+#if NAPI_VERSION >= 7
+inline bool ArrayBuffer::IsDetached() const {
+  bool detached;
+  napi_status status = napi_is_detached_arraybuffer(_env, _value, &detached);
+  NAPI_THROW_IF_FAILED(_env, status, false);
+  return detached;
+}
+
+inline void ArrayBuffer::Detach() {
+  napi_status status = napi_detach_arraybuffer(_env, _value);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+#endif  // NAPI_VERSION >= 7
+
+////////////////////////////////////////////////////////////////////////////////
+// DataView class
+////////////////////////////////////////////////////////////////////////////////
+inline DataView DataView::New(napi_env env, Napi::ArrayBuffer arrayBuffer) {
+  return New(env, arrayBuffer, 0, arrayBuffer.ByteLength());
+}
+
+inline DataView DataView::New(napi_env env,
+                              Napi::ArrayBuffer arrayBuffer,
+                              size_t byteOffset) {
+  if (byteOffset > arrayBuffer.ByteLength()) {
+    NAPI_THROW(RangeError::New(
+                   env, "Start offset is outside the bounds of the buffer"),
+               DataView());
+  }
+  return New(
+      env, arrayBuffer, byteOffset, arrayBuffer.ByteLength() - byteOffset);
+}
+
+inline DataView DataView::New(napi_env env,
+                              Napi::ArrayBuffer arrayBuffer,
+                              size_t byteOffset,
+                              size_t byteLength) {
+  if (byteOffset + byteLength > arrayBuffer.ByteLength()) {
+    NAPI_THROW(RangeError::New(env, "Invalid DataView length"), DataView());
+  }
+  napi_value value;
+  napi_status status =
+      napi_create_dataview(env, byteLength, arrayBuffer, byteOffset, &value);
+  NAPI_THROW_IF_FAILED(env, status, DataView());
+  return DataView(env, value);
+}
+
+inline void DataView::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "DataView::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_dataview(env, value, &result);
+  NAPI_CHECK(
+      status == napi_ok, "DataView::CheckCast", "napi_is_dataview failed");
+  NAPI_CHECK(result, "DataView::CheckCast", "value is not dataview");
+}
+
+inline DataView::DataView() : Object() {}
+
+inline DataView::DataView(napi_env env, napi_value value) : Object(env, value) {
+  napi_status status = napi_get_dataview_info(_env,
+                                              _value /* dataView */,
+                                              &_length /* byteLength */,
+                                              &_data /* data */,
+                                              nullptr /* arrayBuffer */,
+                                              nullptr /* byteOffset */);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline Napi::ArrayBuffer DataView::ArrayBuffer() const {
+  napi_value arrayBuffer;
+  napi_status status = napi_get_dataview_info(_env,
+                                              _value /* dataView */,
+                                              nullptr /* byteLength */,
+                                              nullptr /* data */,
+                                              &arrayBuffer /* arrayBuffer */,
+                                              nullptr /* byteOffset */);
+  NAPI_THROW_IF_FAILED(_env, status, Napi::ArrayBuffer());
+  return Napi::ArrayBuffer(_env, arrayBuffer);
+}
+
+inline size_t DataView::ByteOffset() const {
+  size_t byteOffset;
+  napi_status status = napi_get_dataview_info(_env,
+                                              _value /* dataView */,
+                                              nullptr /* byteLength */,
+                                              nullptr /* data */,
+                                              nullptr /* arrayBuffer */,
+                                              &byteOffset /* byteOffset */);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return byteOffset;
+}
+
+inline size_t DataView::ByteLength() const {
+  return _length;
+}
+
+inline void* DataView::Data() const {
+  return _data;
+}
+
+inline float DataView::GetFloat32(size_t byteOffset) const {
+  return ReadData<float>(byteOffset);
+}
+
+inline double DataView::GetFloat64(size_t byteOffset) const {
+  return ReadData<double>(byteOffset);
+}
+
+inline int8_t DataView::GetInt8(size_t byteOffset) const {
+  return ReadData<int8_t>(byteOffset);
+}
+
+inline int16_t DataView::GetInt16(size_t byteOffset) const {
+  return ReadData<int16_t>(byteOffset);
+}
+
+inline int32_t DataView::GetInt32(size_t byteOffset) const {
+  return ReadData<int32_t>(byteOffset);
+}
+
+inline uint8_t DataView::GetUint8(size_t byteOffset) const {
+  return ReadData<uint8_t>(byteOffset);
+}
+
+inline uint16_t DataView::GetUint16(size_t byteOffset) const {
+  return ReadData<uint16_t>(byteOffset);
+}
+
+inline uint32_t DataView::GetUint32(size_t byteOffset) const {
+  return ReadData<uint32_t>(byteOffset);
+}
+
+inline void DataView::SetFloat32(size_t byteOffset, float value) const {
+  WriteData<float>(byteOffset, value);
+}
+
+inline void DataView::SetFloat64(size_t byteOffset, double value) const {
+  WriteData<double>(byteOffset, value);
+}
+
+inline void DataView::SetInt8(size_t byteOffset, int8_t value) const {
+  WriteData<int8_t>(byteOffset, value);
+}
+
+inline void DataView::SetInt16(size_t byteOffset, int16_t value) const {
+  WriteData<int16_t>(byteOffset, value);
+}
+
+inline void DataView::SetInt32(size_t byteOffset, int32_t value) const {
+  WriteData<int32_t>(byteOffset, value);
+}
+
+inline void DataView::SetUint8(size_t byteOffset, uint8_t value) const {
+  WriteData<uint8_t>(byteOffset, value);
+}
+
+inline void DataView::SetUint16(size_t byteOffset, uint16_t value) const {
+  WriteData<uint16_t>(byteOffset, value);
+}
+
+inline void DataView::SetUint32(size_t byteOffset, uint32_t value) const {
+  WriteData<uint32_t>(byteOffset, value);
+}
+
+template <typename T>
+inline T DataView::ReadData(size_t byteOffset) const {
+  if (byteOffset + sizeof(T) > _length ||
+      byteOffset + sizeof(T) < byteOffset) {  // overflow
+    NAPI_THROW(
+        RangeError::New(_env, "Offset is outside the bounds of the DataView"),
+        0);
+  }
+
+  return *reinterpret_cast<T*>(static_cast<uint8_t*>(_data) + byteOffset);
+}
+
+template <typename T>
+inline void DataView::WriteData(size_t byteOffset, T value) const {
+  if (byteOffset + sizeof(T) > _length ||
+      byteOffset + sizeof(T) < byteOffset) {  // overflow
+    NAPI_THROW_VOID(
+        RangeError::New(_env, "Offset is outside the bounds of the DataView"));
+  }
+
+  *reinterpret_cast<T*>(static_cast<uint8_t*>(_data) + byteOffset) = value;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TypedArray class
+////////////////////////////////////////////////////////////////////////////////
+inline void TypedArray::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "TypedArray::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_typedarray(env, value, &result);
+  NAPI_CHECK(
+      status == napi_ok, "TypedArray::CheckCast", "napi_is_typedarray failed");
+  NAPI_CHECK(result, "TypedArray::CheckCast", "value is not typedarray");
+}
+
+inline TypedArray::TypedArray()
+    : Object(), _type(napi_typedarray_type::napi_int8_array), _length(0) {}
+
+inline TypedArray::TypedArray(napi_env env, napi_value value)
+    : Object(env, value),
+      _type(napi_typedarray_type::napi_int8_array),
+      _length(0) {
+  if (value != nullptr) {
+    napi_status status =
+        napi_get_typedarray_info(_env,
+                                 _value,
+                                 &const_cast<TypedArray*>(this)->_type,
+                                 &const_cast<TypedArray*>(this)->_length,
+                                 nullptr,
+                                 nullptr,
+                                 nullptr);
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+inline TypedArray::TypedArray(napi_env env,
+                              napi_value value,
+                              napi_typedarray_type type,
+                              size_t length)
+    : Object(env, value), _type(type), _length(length) {}
+
+inline napi_typedarray_type TypedArray::TypedArrayType() const {
+  return _type;
+}
+
+inline uint8_t TypedArray::ElementSize() const {
+  switch (_type) {
+    case napi_int8_array:
+    case napi_uint8_array:
+    case napi_uint8_clamped_array:
+      return 1;
+    case napi_int16_array:
+    case napi_uint16_array:
+      return 2;
+    case napi_int32_array:
+    case napi_uint32_array:
+    case napi_float32_array:
+      return 4;
+    case napi_float64_array:
+#if (NAPI_VERSION > 5)
+    case napi_bigint64_array:
+    case napi_biguint64_array:
+#endif  // (NAPI_VERSION > 5)
+      return 8;
+    default:
+      return 0;
+  }
+}
+
+inline size_t TypedArray::ElementLength() const {
+  return _length;
+}
+
+inline size_t TypedArray::ByteOffset() const {
+  size_t byteOffset;
+  napi_status status = napi_get_typedarray_info(
+      _env, _value, nullptr, nullptr, nullptr, nullptr, &byteOffset);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return byteOffset;
+}
+
+inline size_t TypedArray::ByteLength() const {
+  return ElementSize() * ElementLength();
+}
+
+inline Napi::ArrayBuffer TypedArray::ArrayBuffer() const {
+  napi_value arrayBuffer;
+  napi_status status = napi_get_typedarray_info(
+      _env, _value, nullptr, nullptr, nullptr, &arrayBuffer, nullptr);
+  NAPI_THROW_IF_FAILED(_env, status, Napi::ArrayBuffer());
+  return Napi::ArrayBuffer(_env, arrayBuffer);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TypedArrayOf<T> class
+////////////////////////////////////////////////////////////////////////////////
+template <typename T>
+inline void TypedArrayOf<T>::CheckCast(napi_env env, napi_value value) {
+  TypedArray::CheckCast(env, value);
+  napi_typedarray_type type;
+  napi_status status = napi_get_typedarray_info(
+      env, value, &type, nullptr, nullptr, nullptr, nullptr);
+  NAPI_CHECK(status == napi_ok,
+             "TypedArrayOf::CheckCast",
+             "napi_is_typedarray failed");
+
+  NAPI_CHECK(
+      (type == TypedArrayTypeForPrimitiveType<T>() ||
+       (type == napi_uint8_clamped_array && std::is_same<T, uint8_t>::value)),
+      "TypedArrayOf::CheckCast",
+      "Array type must match the template parameter. (Uint8 arrays may "
+      "optionally have the \"clamped\" array type.)");
+}
+
+template <typename T>
+inline TypedArrayOf<T> TypedArrayOf<T>::New(napi_env env,
+                                            size_t elementLength,
+                                            napi_typedarray_type type) {
+  Napi::ArrayBuffer arrayBuffer =
+      Napi::ArrayBuffer::New(env, elementLength * sizeof(T));
+  return New(env, elementLength, arrayBuffer, 0, type);
+}
+
+template <typename T>
+inline TypedArrayOf<T> TypedArrayOf<T>::New(napi_env env,
+                                            size_t elementLength,
+                                            Napi::ArrayBuffer arrayBuffer,
+                                            size_t bufferOffset,
+                                            napi_typedarray_type type) {
+  napi_value value;
+  napi_status status = napi_create_typedarray(
+      env, type, elementLength, arrayBuffer, bufferOffset, &value);
+  NAPI_THROW_IF_FAILED(env, status, TypedArrayOf<T>());
+
+  return TypedArrayOf<T>(
+      env,
+      value,
+      type,
+      elementLength,
+      reinterpret_cast<T*>(reinterpret_cast<uint8_t*>(arrayBuffer.Data()) +
+                           bufferOffset));
+}
+
+template <typename T>
+inline TypedArrayOf<T>::TypedArrayOf() : TypedArray(), _data(nullptr) {}
+
+template <typename T>
+inline TypedArrayOf<T>::TypedArrayOf(napi_env env, napi_value value)
+    : TypedArray(env, value), _data(nullptr) {
+  napi_status status = napi_ok;
+  if (value != nullptr) {
+    void* data = nullptr;
+    status = napi_get_typedarray_info(
+        _env, _value, &_type, &_length, &data, nullptr, nullptr);
+    _data = static_cast<T*>(data);
+  } else {
+    _type = TypedArrayTypeForPrimitiveType<T>();
+    _length = 0;
+  }
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+template <typename T>
+inline TypedArrayOf<T>::TypedArrayOf(napi_env env,
+                                     napi_value value,
+                                     napi_typedarray_type type,
+                                     size_t length,
+                                     T* data)
+    : TypedArray(env, value, type, length), _data(data) {
+  if (!(type == TypedArrayTypeForPrimitiveType<T>() ||
+        (type == napi_uint8_clamped_array &&
+         std::is_same<T, uint8_t>::value))) {
+    NAPI_THROW_VOID(TypeError::New(
+        env,
+        "Array type must match the template parameter. "
+        "(Uint8 arrays may optionally have the \"clamped\" array type.)"));
+  }
+}
+
+template <typename T>
+inline T& TypedArrayOf<T>::operator[](size_t index) {
+  return _data[index];
+}
+
+template <typename T>
+inline const T& TypedArrayOf<T>::operator[](size_t index) const {
+  return _data[index];
+}
+
+template <typename T>
+inline T* TypedArrayOf<T>::Data() {
+  return _data;
+}
+
+template <typename T>
+inline const T* TypedArrayOf<T>::Data() const {
+  return _data;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Function class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename CbData>
+inline napi_status CreateFunction(napi_env env,
+                                  const char* utf8name,
+                                  napi_callback cb,
+                                  CbData* data,
+                                  napi_value* result) {
+  napi_status status =
+      napi_create_function(env, utf8name, NAPI_AUTO_LENGTH, cb, data, result);
+  if (status == napi_ok) {
+    status = Napi::details::AttachData(env, *result, data);
+  }
+
+  return status;
+}
+
+template <Function::VoidCallback cb>
+inline Function Function::New(napi_env env, const char* utf8name, void* data) {
+  napi_value result = nullptr;
+  napi_status status = napi_create_function(env,
+                                            utf8name,
+                                            NAPI_AUTO_LENGTH,
+                                            details::TemplatedVoidCallback<cb>,
+                                            data,
+                                            &result);
+  NAPI_THROW_IF_FAILED(env, status, Function());
+  return Function(env, result);
+}
+
+template <Function::Callback cb>
+inline Function Function::New(napi_env env, const char* utf8name, void* data) {
+  napi_value result = nullptr;
+  napi_status status = napi_create_function(env,
+                                            utf8name,
+                                            NAPI_AUTO_LENGTH,
+                                            details::TemplatedCallback<cb>,
+                                            data,
+                                            &result);
+  NAPI_THROW_IF_FAILED(env, status, Function());
+  return Function(env, result);
+}
+
+template <Function::VoidCallback cb>
+inline Function Function::New(napi_env env,
+                              const std::string& utf8name,
+                              void* data) {
+  return Function::New<cb>(env, utf8name.c_str(), data);
+}
+
+template <Function::Callback cb>
+inline Function Function::New(napi_env env,
+                              const std::string& utf8name,
+                              void* data) {
+  return Function::New<cb>(env, utf8name.c_str(), data);
+}
+
+template <typename Callable>
+inline Function Function::New(napi_env env,
+                              Callable cb,
+                              const char* utf8name,
+                              void* data) {
+  using ReturnType = decltype(cb(CallbackInfo(nullptr, nullptr)));
+  using CbData = details::CallbackData<Callable, ReturnType>;
+  auto callbackData = new CbData{std::move(cb), data};
+
+  napi_value value;
+  napi_status status =
+      CreateFunction(env, utf8name, CbData::Wrapper, callbackData, &value);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, Function());
+  }
+
+  return Function(env, value);
+}
+
+template <typename Callable>
+inline Function Function::New(napi_env env,
+                              Callable cb,
+                              const std::string& utf8name,
+                              void* data) {
+  return New(env, cb, utf8name.c_str(), data);
+}
+
+inline void Function::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Function::CheckCast", "empty value");
+
+  napi_valuetype type;
+  napi_status status = napi_typeof(env, value, &type);
+  NAPI_CHECK(status == napi_ok, "Function::CheckCast", "napi_typeof failed");
+  NAPI_CHECK(type == napi_function,
+             "Function::CheckCast",
+             "value is not napi_function");
+}
+
+inline Function::Function() : Object() {}
+
+inline Function::Function(napi_env env, napi_value value)
+    : Object(env, value) {}
+
+inline MaybeOrValue<Value> Function::operator()(
+    const std::initializer_list<napi_value>& args) const {
+  return Call(Env().Undefined(), args);
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    const std::initializer_list<napi_value>& args) const {
+  return Call(Env().Undefined(), args);
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    const std::vector<napi_value>& args) const {
+  return Call(Env().Undefined(), args);
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    const std::vector<Value>& args) const {
+  return Call(Env().Undefined(), args);
+}
+
+inline MaybeOrValue<Value> Function::Call(size_t argc,
+                                          const napi_value* args) const {
+  return Call(Env().Undefined(), argc, args);
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    napi_value recv, const std::initializer_list<napi_value>& args) const {
+  return Call(recv, args.size(), args.begin());
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    napi_value recv, const std::vector<napi_value>& args) const {
+  return Call(recv, args.size(), args.data());
+}
+
+inline MaybeOrValue<Value> Function::Call(
+    napi_value recv, const std::vector<Value>& args) const {
+  const size_t argc = args.size();
+  const size_t stackArgsCount = 6;
+  napi_value stackArgs[stackArgsCount];
+  std::vector<napi_value> heapArgs;
+  napi_value* argv;
+  if (argc <= stackArgsCount) {
+    argv = stackArgs;
+  } else {
+    heapArgs.resize(argc);
+    argv = heapArgs.data();
+  }
+
+  for (size_t index = 0; index < argc; index++) {
+    argv[index] = static_cast<napi_value>(args[index]);
+  }
+
+  return Call(recv, argc, argv);
+}
+
+inline MaybeOrValue<Value> Function::Call(napi_value recv,
+                                          size_t argc,
+                                          const napi_value* args) const {
+  napi_value result;
+  napi_status status =
+      napi_call_function(_env, recv, _value, argc, args, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Value(_env, result), Napi::Value);
+}
+
+inline MaybeOrValue<Value> Function::MakeCallback(
+    napi_value recv,
+    const std::initializer_list<napi_value>& args,
+    napi_async_context context) const {
+  return MakeCallback(recv, args.size(), args.begin(), context);
+}
+
+inline MaybeOrValue<Value> Function::MakeCallback(
+    napi_value recv,
+    const std::vector<napi_value>& args,
+    napi_async_context context) const {
+  return MakeCallback(recv, args.size(), args.data(), context);
+}
+
+inline MaybeOrValue<Value> Function::MakeCallback(
+    napi_value recv,
+    size_t argc,
+    const napi_value* args,
+    napi_async_context context) const {
+  napi_value result;
+  napi_status status =
+      napi_make_callback(_env, context, recv, _value, argc, args, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Value(_env, result), Napi::Value);
+}
+
+inline MaybeOrValue<Object> Function::New(
+    const std::initializer_list<napi_value>& args) const {
+  return New(args.size(), args.begin());
+}
+
+inline MaybeOrValue<Object> Function::New(
+    const std::vector<napi_value>& args) const {
+  return New(args.size(), args.data());
+}
+
+inline MaybeOrValue<Object> Function::New(size_t argc,
+                                          const napi_value* args) const {
+  napi_value result;
+  napi_status status = napi_new_instance(_env, _value, argc, args, &result);
+  NAPI_RETURN_OR_THROW_IF_FAILED(
+      _env, status, Napi::Object(_env, result), Napi::Object);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Promise class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Promise::Deferred Promise::Deferred::New(napi_env env) {
+  return Promise::Deferred(env);
+}
+
+inline Promise::Deferred::Deferred(napi_env env) : _env(env) {
+  napi_status status = napi_create_promise(_env, &_deferred, &_promise);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline Promise Promise::Deferred::Promise() const {
+  return Napi::Promise(_env, _promise);
+}
+
+inline Napi::Env Promise::Deferred::Env() const {
+  return Napi::Env(_env);
+}
+
+inline void Promise::Deferred::Resolve(napi_value value) const {
+  napi_status status = napi_resolve_deferred(_env, _deferred, value);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline void Promise::Deferred::Reject(napi_value value) const {
+  napi_status status = napi_reject_deferred(_env, _deferred, value);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline void Promise::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Promise::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_promise(env, value, &result);
+  NAPI_CHECK(status == napi_ok, "Promise::CheckCast", "napi_is_promise failed");
+  NAPI_CHECK(result, "Promise::CheckCast", "value is not promise");
+}
+
+inline Promise::Promise(napi_env env, napi_value value) : Object(env, value) {}
+
+////////////////////////////////////////////////////////////////////////////////
+// Buffer<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline Buffer<T> Buffer<T>::New(napi_env env, size_t length) {
+  napi_value value;
+  void* data;
+  napi_status status =
+      napi_create_buffer(env, length * sizeof(T), &data, &value);
+  NAPI_THROW_IF_FAILED(env, status, Buffer<T>());
+  return Buffer(env, value);
+}
+
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+template <typename T>
+inline Buffer<T> Buffer<T>::New(napi_env env, T* data, size_t length) {
+  napi_value value;
+  napi_status status = napi_create_external_buffer(
+      env, length * sizeof(T), data, nullptr, nullptr, &value);
+  NAPI_THROW_IF_FAILED(env, status, Buffer<T>());
+  return Buffer(env, value);
+}
+
+template <typename T>
+template <typename Finalizer>
+inline Buffer<T> Buffer<T>::New(napi_env env,
+                                T* data,
+                                size_t length,
+                                Finalizer finalizeCallback) {
+  napi_value value;
+  details::FinalizeData<T, Finalizer>* finalizeData =
+      new details::FinalizeData<T, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+  napi_status status =
+      napi_create_external_buffer(env,
+                                  length * sizeof(T),
+                                  data,
+                                  details::FinalizeData<T, Finalizer>::Wrapper,
+                                  finalizeData,
+                                  &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, Buffer());
+  }
+  return Buffer(env, value);
+}
+
+template <typename T>
+template <typename Finalizer, typename Hint>
+inline Buffer<T> Buffer<T>::New(napi_env env,
+                                T* data,
+                                size_t length,
+                                Finalizer finalizeCallback,
+                                Hint* finalizeHint) {
+  napi_value value;
+  details::FinalizeData<T, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<T, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+  napi_status status = napi_create_external_buffer(
+      env,
+      length * sizeof(T),
+      data,
+      details::FinalizeData<T, Finalizer, Hint>::WrapperWithHint,
+      finalizeData,
+      &value);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, Buffer());
+  }
+  return Buffer(env, value);
+}
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+
+template <typename T>
+inline Buffer<T> Buffer<T>::NewOrCopy(napi_env env, T* data, size_t length) {
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  napi_value value;
+  napi_status status = napi_create_external_buffer(
+      env, length * sizeof(T), data, nullptr, nullptr, &value);
+  if (status == details::napi_no_external_buffers_allowed) {
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+    // If we can't create an external buffer, we'll just copy the data.
+    return Buffer<T>::Copy(env, data, length);
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  }
+  NAPI_THROW_IF_FAILED(env, status, Buffer<T>());
+  return Buffer(env, value);
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+}
+
+template <typename T>
+template <typename Finalizer>
+inline Buffer<T> Buffer<T>::NewOrCopy(napi_env env,
+                                      T* data,
+                                      size_t length,
+                                      Finalizer finalizeCallback) {
+  details::FinalizeData<T, Finalizer>* finalizeData =
+      new details::FinalizeData<T, Finalizer>(
+          {std::move(finalizeCallback), nullptr});
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  napi_value value;
+  napi_status status =
+      napi_create_external_buffer(env,
+                                  length * sizeof(T),
+                                  data,
+                                  details::FinalizeData<T, Finalizer>::Wrapper,
+                                  finalizeData,
+                                  &value);
+  if (status == details::napi_no_external_buffers_allowed) {
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+    // If we can't create an external buffer, we'll just copy the data.
+    Buffer<T> ret = Buffer<T>::Copy(env, data, length);
+    details::FinalizeData<T, Finalizer>::Wrapper(env, data, finalizeData);
+    return ret;
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  }
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, Buffer());
+  }
+  return Buffer(env, value);
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+}
+
+template <typename T>
+template <typename Finalizer, typename Hint>
+inline Buffer<T> Buffer<T>::NewOrCopy(napi_env env,
+                                      T* data,
+                                      size_t length,
+                                      Finalizer finalizeCallback,
+                                      Hint* finalizeHint) {
+  details::FinalizeData<T, Finalizer, Hint>* finalizeData =
+      new details::FinalizeData<T, Finalizer, Hint>(
+          {std::move(finalizeCallback), finalizeHint});
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  napi_value value;
+  napi_status status = napi_create_external_buffer(
+      env,
+      length * sizeof(T),
+      data,
+      details::FinalizeData<T, Finalizer, Hint>::WrapperWithHint,
+      finalizeData,
+      &value);
+  if (status == details::napi_no_external_buffers_allowed) {
+#endif
+    // If we can't create an external buffer, we'll just copy the data.
+    Buffer<T> ret = Buffer<T>::Copy(env, data, length);
+    details::FinalizeData<T, Finalizer, Hint>::WrapperWithHint(
+        env, data, finalizeData);
+    return ret;
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  }
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, Buffer());
+  }
+  return Buffer(env, value);
+#endif
+}
+
+template <typename T>
+inline Buffer<T> Buffer<T>::Copy(napi_env env, const T* data, size_t length) {
+  napi_value value;
+  napi_status status =
+      napi_create_buffer_copy(env, length * sizeof(T), data, nullptr, &value);
+  NAPI_THROW_IF_FAILED(env, status, Buffer<T>());
+  return Buffer<T>(env, value);
+}
+
+template <typename T>
+inline void Buffer<T>::CheckCast(napi_env env, napi_value value) {
+  NAPI_CHECK(value != nullptr, "Buffer::CheckCast", "empty value");
+
+  bool result;
+  napi_status status = napi_is_buffer(env, value, &result);
+  NAPI_CHECK(status == napi_ok, "Buffer::CheckCast", "napi_is_buffer failed");
+  NAPI_CHECK(result, "Buffer::CheckCast", "value is not buffer");
+}
+
+template <typename T>
+inline Buffer<T>::Buffer() : Uint8Array() {}
+
+template <typename T>
+inline Buffer<T>::Buffer(napi_env env, napi_value value)
+    : Uint8Array(env, value) {}
+
+template <typename T>
+inline size_t Buffer<T>::Length() const {
+  return ByteLength() / sizeof(T);
+}
+
+template <typename T>
+inline T* Buffer<T>::Data() const {
+  return reinterpret_cast<T*>(const_cast<uint8_t*>(Uint8Array::Data()));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Error class
+////////////////////////////////////////////////////////////////////////////////
+
+inline Error Error::New(napi_env env) {
+  napi_status status;
+  napi_value error = nullptr;
+  bool is_exception_pending;
+  napi_extended_error_info last_error_info_copy;
+
+  {
+    // We must retrieve the last error info before doing anything else because
+    // doing anything else will replace the last error info.
+    const napi_extended_error_info* last_error_info;
+    status = napi_get_last_error_info(env, &last_error_info);
+    NAPI_FATAL_IF_FAILED(status, "Error::New", "napi_get_last_error_info");
+
+    // All fields of the `napi_extended_error_info` structure gets reset in
+    // subsequent Node-API function calls on the same `env`. This includes a
+    // call to `napi_is_exception_pending()`. So here it is necessary to make a
+    // copy of the information as the `error_code` field is used later on.
+    memcpy(&last_error_info_copy,
+           last_error_info,
+           sizeof(napi_extended_error_info));
+  }
+
+  status = napi_is_exception_pending(env, &is_exception_pending);
+  NAPI_FATAL_IF_FAILED(status, "Error::New", "napi_is_exception_pending");
+
+  // A pending exception takes precedence over any internal error status.
+  if (is_exception_pending) {
+    status = napi_get_and_clear_last_exception(env, &error);
+    NAPI_FATAL_IF_FAILED(
+        status, "Error::New", "napi_get_and_clear_last_exception");
+  } else {
+    const char* error_message = last_error_info_copy.error_message != nullptr
+                                    ? last_error_info_copy.error_message
+                                    : "Error in native callback";
+
+    napi_value message;
+    status = napi_create_string_utf8(
+        env, error_message, std::strlen(error_message), &message);
+    NAPI_FATAL_IF_FAILED(status, "Error::New", "napi_create_string_utf8");
+
+    switch (last_error_info_copy.error_code) {
+      case napi_object_expected:
+      case napi_string_expected:
+      case napi_boolean_expected:
+      case napi_number_expected:
+        status = napi_create_type_error(env, nullptr, message, &error);
+        break;
+      default:
+        status = napi_create_error(env, nullptr, message, &error);
+        break;
+    }
+    NAPI_FATAL_IF_FAILED(status, "Error::New", "napi_create_error");
+  }
+
+  return Error(env, error);
+}
+
+inline Error Error::New(napi_env env, const char* message) {
+  return Error::New<Error>(
+      env, message, std::strlen(message), napi_create_error);
+}
+
+inline Error Error::New(napi_env env, const std::string& message) {
+  return Error::New<Error>(
+      env, message.c_str(), message.size(), napi_create_error);
+}
+
+inline NAPI_NO_RETURN void Error::Fatal(const char* location,
+                                        const char* message) {
+  napi_fatal_error(location, NAPI_AUTO_LENGTH, message, NAPI_AUTO_LENGTH);
+}
+
+inline Error::Error() : ObjectReference() {}
+
+inline Error::Error(napi_env env, napi_value value)
+    : ObjectReference(env, nullptr) {
+  if (value != nullptr) {
+    // Attempting to create a reference on the error object.
+    // If it's not a Object/Function/Symbol, this call will return an error
+    // status.
+    napi_status status = napi_create_reference(env, value, 1, &_ref);
+
+    if (status != napi_ok) {
+      napi_value wrappedErrorObj;
+
+      // Create an error object
+      status = napi_create_object(env, &wrappedErrorObj);
+      NAPI_FATAL_IF_FAILED(status, "Error::Error", "napi_create_object");
+
+      // property flag that we attach to show the error object is wrapped
+      napi_property_descriptor wrapObjFlag = {
+          ERROR_WRAP_VALUE(),  // Unique GUID identifier since Symbol isn't a
+                               // viable option
+          nullptr,
+          nullptr,
+          nullptr,
+          nullptr,
+          Value::From(env, value),
+          napi_enumerable,
+          nullptr};
+
+      status = napi_define_properties(env, wrappedErrorObj, 1, &wrapObjFlag);
+#ifdef NODE_API_SWALLOW_UNTHROWABLE_EXCEPTIONS
+      if (status == napi_pending_exception) {
+        // Test if the pending exception was reported because the environment is
+        // shutting down. We assume that a status of napi_pending_exception
+        // coupled with the absence of an actual pending exception means that
+        // the environment is shutting down. If so, we replace the
+        // napi_pending_exception status with napi_ok.
+        bool is_exception_pending = false;
+        status = napi_is_exception_pending(env, &is_exception_pending);
+        if (status == napi_ok && !is_exception_pending) {
+          status = napi_ok;
+        } else {
+          status = napi_pending_exception;
+        }
+      }
+#endif  // NODE_API_SWALLOW_UNTHROWABLE_EXCEPTIONS
+      NAPI_FATAL_IF_FAILED(status, "Error::Error", "napi_define_properties");
+
+      // Create a reference on the newly wrapped object
+      status = napi_create_reference(env, wrappedErrorObj, 1, &_ref);
+    }
+
+    // Avoid infinite recursion in the failure case.
+    NAPI_FATAL_IF_FAILED(status, "Error::Error", "napi_create_reference");
+  }
+}
+
+inline Object Error::Value() const {
+  if (_ref == nullptr) {
+    return Object(_env, nullptr);
+  }
+
+  napi_value refValue;
+  napi_status status = napi_get_reference_value(_env, _ref, &refValue);
+  NAPI_THROW_IF_FAILED(_env, status, Object());
+
+  napi_valuetype type;
+  status = napi_typeof(_env, refValue, &type);
+  NAPI_THROW_IF_FAILED(_env, status, Object());
+
+  // If refValue isn't a symbol, then we proceed to whether the refValue has the
+  // wrapped error flag
+  if (type != napi_symbol) {
+    // We are checking if the object is wrapped
+    bool isWrappedObject = false;
+
+    status = napi_has_property(_env,
+                               refValue,
+                               String::From(_env, ERROR_WRAP_VALUE()),
+                               &isWrappedObject);
+
+    // Don't care about status
+    if (isWrappedObject) {
+      napi_value unwrappedValue;
+      status = napi_get_property(_env,
+                                 refValue,
+                                 String::From(_env, ERROR_WRAP_VALUE()),
+                                 &unwrappedValue);
+      NAPI_THROW_IF_FAILED(_env, status, Object());
+
+      return Object(_env, unwrappedValue);
+    }
+  }
+
+  return Object(_env, refValue);
+}
+
+inline Error::Error(Error&& other) : ObjectReference(std::move(other)) {}
+
+inline Error& Error::operator=(Error&& other) {
+  static_cast<Reference<Object>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline Error::Error(const Error& other) : ObjectReference(other) {}
+
+inline Error& Error::operator=(const Error& other) {
+  Reset();
+
+  _env = other.Env();
+  HandleScope scope(_env);
+
+  napi_value value = other.Value();
+  if (value != nullptr) {
+    napi_status status = napi_create_reference(_env, value, 1, &_ref);
+    NAPI_THROW_IF_FAILED(_env, status, *this);
+  }
+
+  return *this;
+}
+
+inline const std::string& Error::Message() const NAPI_NOEXCEPT {
+  if (_message.size() == 0 && _env != nullptr) {
+#ifdef NAPI_CPP_EXCEPTIONS
+    try {
+      _message = Get("message").As<String>();
+    } catch (...) {
+      // Catch all errors here, to include e.g. a std::bad_alloc from
+      // the std::string::operator=, because this method may not throw.
+    }
+#else  // NAPI_CPP_EXCEPTIONS
+#if defined(NODE_ADDON_API_ENABLE_MAYBE)
+    Napi::Value message_val;
+    if (Get("message").UnwrapTo(&message_val)) {
+      _message = message_val.As<String>();
+    }
+#else
+    _message = Get("message").As<String>();
+#endif
+#endif  // NAPI_CPP_EXCEPTIONS
+  }
+  return _message;
+}
+
+// we created an object on the &_ref
+inline void Error::ThrowAsJavaScriptException() const {
+  HandleScope scope(_env);
+  if (!IsEmpty()) {
+#ifdef NODE_API_SWALLOW_UNTHROWABLE_EXCEPTIONS
+    bool pendingException = false;
+
+    // check if there is already a pending exception. If so don't try to throw a
+    // new one as that is not allowed/possible
+    napi_status status = napi_is_exception_pending(_env, &pendingException);
+
+    if ((status != napi_ok) ||
+        ((status == napi_ok) && (pendingException == false))) {
+      // We intentionally don't use `NAPI_THROW_*` macros here to ensure
+      // that there is no possible recursion as `ThrowAsJavaScriptException`
+      // is part of `NAPI_THROW_*` macro definition for noexcept.
+
+      status = napi_throw(_env, Value());
+
+      if (status == napi_pending_exception) {
+        // The environment must be terminating as we checked earlier and there
+        // was no pending exception. In this case continuing will result
+        // in a fatal error and there is nothing the author has done incorrectly
+        // in their code that is worth flagging through a fatal error
+        return;
+      }
+    } else {
+      status = napi_pending_exception;
+    }
+#else
+    // We intentionally don't use `NAPI_THROW_*` macros here to ensure
+    // that there is no possible recursion as `ThrowAsJavaScriptException`
+    // is part of `NAPI_THROW_*` macro definition for noexcept.
+
+    napi_status status = napi_throw(_env, Value());
+#endif
+
+#ifdef NAPI_CPP_EXCEPTIONS
+    if (status != napi_ok) {
+      throw Error::New(_env);
+    }
+#else   // NAPI_CPP_EXCEPTIONS
+    NAPI_FATAL_IF_FAILED(
+        status, "Error::ThrowAsJavaScriptException", "napi_throw");
+#endif  // NAPI_CPP_EXCEPTIONS
+  }
+}
+
+#ifdef NAPI_CPP_EXCEPTIONS
+
+inline const char* Error::what() const NAPI_NOEXCEPT {
+  return Message().c_str();
+}
+
+#endif  // NAPI_CPP_EXCEPTIONS
+
+inline const char* Error::ERROR_WRAP_VALUE() NAPI_NOEXCEPT {
+  return "4bda9e7e-4913-4dbc-95de-891cbf66598e-errorVal";
+}
+
+template <typename TError>
+inline TError Error::New(napi_env env,
+                         const char* message,
+                         size_t length,
+                         create_error_fn create_error) {
+  napi_value str;
+  napi_status status = napi_create_string_utf8(env, message, length, &str);
+  NAPI_THROW_IF_FAILED(env, status, TError());
+
+  napi_value error;
+  status = create_error(env, nullptr, str, &error);
+  NAPI_THROW_IF_FAILED(env, status, TError());
+
+  return TError(env, error);
+}
+
+inline TypeError TypeError::New(napi_env env, const char* message) {
+  return Error::New<TypeError>(
+      env, message, std::strlen(message), napi_create_type_error);
+}
+
+inline TypeError TypeError::New(napi_env env, const std::string& message) {
+  return Error::New<TypeError>(
+      env, message.c_str(), message.size(), napi_create_type_error);
+}
+
+inline TypeError::TypeError() : Error() {}
+
+inline TypeError::TypeError(napi_env env, napi_value value)
+    : Error(env, value) {}
+
+inline RangeError RangeError::New(napi_env env, const char* message) {
+  return Error::New<RangeError>(
+      env, message, std::strlen(message), napi_create_range_error);
+}
+
+inline RangeError RangeError::New(napi_env env, const std::string& message) {
+  return Error::New<RangeError>(
+      env, message.c_str(), message.size(), napi_create_range_error);
+}
+
+inline RangeError::RangeError() : Error() {}
+
+inline RangeError::RangeError(napi_env env, napi_value value)
+    : Error(env, value) {}
+
+#if NAPI_VERSION > 8
+inline SyntaxError SyntaxError::New(napi_env env, const char* message) {
+  return Error::New<SyntaxError>(
+      env, message, std::strlen(message), node_api_create_syntax_error);
+}
+
+inline SyntaxError SyntaxError::New(napi_env env, const std::string& message) {
+  return Error::New<SyntaxError>(
+      env, message.c_str(), message.size(), node_api_create_syntax_error);
+}
+
+inline SyntaxError::SyntaxError() : Error() {}
+
+inline SyntaxError::SyntaxError(napi_env env, napi_value value)
+    : Error(env, value) {}
+#endif  // NAPI_VERSION > 8
+
+////////////////////////////////////////////////////////////////////////////////
+// Reference<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline Reference<T> Reference<T>::New(const T& value,
+                                      uint32_t initialRefcount) {
+  napi_env env = value.Env();
+  napi_value val = value;
+
+  if (val == nullptr) {
+    return Reference<T>(env, nullptr);
+  }
+
+  napi_ref ref;
+  napi_status status = napi_create_reference(env, value, initialRefcount, &ref);
+  NAPI_THROW_IF_FAILED(env, status, Reference<T>());
+
+  return Reference<T>(env, ref);
+}
+
+template <typename T>
+inline Reference<T>::Reference()
+    : _env(nullptr), _ref(nullptr), _suppressDestruct(false) {}
+
+template <typename T>
+inline Reference<T>::Reference(napi_env env, napi_ref ref)
+    : _env(env), _ref(ref), _suppressDestruct(false) {}
+
+template <typename T>
+inline Reference<T>::~Reference() {
+  if (_ref != nullptr) {
+    if (!_suppressDestruct) {
+      napi_delete_reference(_env, _ref);
+    }
+
+    _ref = nullptr;
+  }
+}
+
+template <typename T>
+inline Reference<T>::Reference(Reference<T>&& other)
+    : _env(other._env),
+      _ref(other._ref),
+      _suppressDestruct(other._suppressDestruct) {
+  other._env = nullptr;
+  other._ref = nullptr;
+  other._suppressDestruct = false;
+}
+
+template <typename T>
+inline Reference<T>& Reference<T>::operator=(Reference<T>&& other) {
+  Reset();
+  _env = other._env;
+  _ref = other._ref;
+  _suppressDestruct = other._suppressDestruct;
+  other._env = nullptr;
+  other._ref = nullptr;
+  other._suppressDestruct = false;
+  return *this;
+}
+
+template <typename T>
+inline Reference<T>::Reference(const Reference<T>& other)
+    : _env(other._env), _ref(nullptr), _suppressDestruct(false) {
+  HandleScope scope(_env);
+
+  napi_value value = other.Value();
+  if (value != nullptr) {
+    // Copying is a limited scenario (currently only used for Error object) and
+    // always creates a strong reference to the given value even if the incoming
+    // reference is weak.
+    napi_status status = napi_create_reference(_env, value, 1, &_ref);
+    NAPI_FATAL_IF_FAILED(
+        status, "Reference<T>::Reference", "napi_create_reference");
+  }
+}
+
+template <typename T>
+inline Reference<T>::operator napi_ref() const {
+  return _ref;
+}
+
+template <typename T>
+inline bool Reference<T>::operator==(const Reference<T>& other) const {
+  HandleScope scope(_env);
+  return this->Value().StrictEquals(other.Value());
+}
+
+template <typename T>
+inline bool Reference<T>::operator!=(const Reference<T>& other) const {
+  return !this->operator==(other);
+}
+
+template <typename T>
+inline Napi::Env Reference<T>::Env() const {
+  return Napi::Env(_env);
+}
+
+template <typename T>
+inline bool Reference<T>::IsEmpty() const {
+  return _ref == nullptr;
+}
+
+template <typename T>
+inline T Reference<T>::Value() const {
+  if (_ref == nullptr) {
+    return T(_env, nullptr);
+  }
+
+  napi_value value;
+  napi_status status = napi_get_reference_value(_env, _ref, &value);
+  NAPI_THROW_IF_FAILED(_env, status, T());
+  return T(_env, value);
+}
+
+template <typename T>
+inline uint32_t Reference<T>::Ref() const {
+  uint32_t result;
+  napi_status status = napi_reference_ref(_env, _ref, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+template <typename T>
+inline uint32_t Reference<T>::Unref() const {
+  uint32_t result;
+  napi_status status = napi_reference_unref(_env, _ref, &result);
+  NAPI_THROW_IF_FAILED(_env, status, 0);
+  return result;
+}
+
+template <typename T>
+inline void Reference<T>::Reset() {
+  if (_ref != nullptr) {
+    napi_status status = napi_delete_reference(_env, _ref);
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+    _ref = nullptr;
+  }
+}
+
+template <typename T>
+inline void Reference<T>::Reset(const T& value, uint32_t refcount) {
+  Reset();
+  _env = value.Env();
+
+  napi_value val = value;
+  if (val != nullptr) {
+    napi_status status = napi_create_reference(_env, value, refcount, &_ref);
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+template <typename T>
+inline void Reference<T>::SuppressDestruct() {
+  _suppressDestruct = true;
+}
+
+template <typename T>
+inline Reference<T> Weak(T value) {
+  return Reference<T>::New(value, 0);
+}
+
+inline ObjectReference Weak(Object value) {
+  return Reference<Object>::New(value, 0);
+}
+
+inline FunctionReference Weak(Function value) {
+  return Reference<Function>::New(value, 0);
+}
+
+template <typename T>
+inline Reference<T> Persistent(T value) {
+  return Reference<T>::New(value, 1);
+}
+
+inline ObjectReference Persistent(Object value) {
+  return Reference<Object>::New(value, 1);
+}
+
+inline FunctionReference Persistent(Function value) {
+  return Reference<Function>::New(value, 1);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ObjectReference class
+////////////////////////////////////////////////////////////////////////////////
+
+inline ObjectReference::ObjectReference() : Reference<Object>() {}
+
+inline ObjectReference::ObjectReference(napi_env env, napi_ref ref)
+    : Reference<Object>(env, ref) {}
+
+inline ObjectReference::ObjectReference(Reference<Object>&& other)
+    : Reference<Object>(std::move(other)) {}
+
+inline ObjectReference& ObjectReference::operator=(Reference<Object>&& other) {
+  static_cast<Reference<Object>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline ObjectReference::ObjectReference(ObjectReference&& other)
+    : Reference<Object>(std::move(other)) {}
+
+inline ObjectReference& ObjectReference::operator=(ObjectReference&& other) {
+  static_cast<Reference<Object>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline ObjectReference::ObjectReference(const ObjectReference& other)
+    : Reference<Object>(other) {}
+
+inline MaybeOrValue<Napi::Value> ObjectReference::Get(
+    const char* utf8name) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Get(utf8name);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> ObjectReference::Get(
+    const std::string& utf8name) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Get(utf8name);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               napi_value value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               Napi::Value value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               const char* utf8value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, utf8value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               bool boolValue) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, boolValue);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const char* utf8name,
+                                               double numberValue) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, numberValue);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               napi_value value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               Napi::Value value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               std::string& utf8value) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, utf8value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               bool boolValue) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, boolValue);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(const std::string& utf8name,
+                                               double numberValue) const {
+  HandleScope scope(_env);
+  return Value().Set(utf8name, numberValue);
+}
+
+inline MaybeOrValue<Napi::Value> ObjectReference::Get(uint32_t index) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Get(index);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               napi_value value) const {
+  HandleScope scope(_env);
+  return Value().Set(index, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               Napi::Value value) const {
+  HandleScope scope(_env);
+  return Value().Set(index, value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               const char* utf8value) const {
+  HandleScope scope(_env);
+  return Value().Set(index, utf8value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(
+    uint32_t index, const std::string& utf8value) const {
+  HandleScope scope(_env);
+  return Value().Set(index, utf8value);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               bool boolValue) const {
+  HandleScope scope(_env);
+  return Value().Set(index, boolValue);
+}
+
+inline MaybeOrValue<bool> ObjectReference::Set(uint32_t index,
+                                               double numberValue) const {
+  HandleScope scope(_env);
+  return Value().Set(index, numberValue);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// FunctionReference class
+////////////////////////////////////////////////////////////////////////////////
+
+inline FunctionReference::FunctionReference() : Reference<Function>() {}
+
+inline FunctionReference::FunctionReference(napi_env env, napi_ref ref)
+    : Reference<Function>(env, ref) {}
+
+inline FunctionReference::FunctionReference(Reference<Function>&& other)
+    : Reference<Function>(std::move(other)) {}
+
+inline FunctionReference& FunctionReference::operator=(
+    Reference<Function>&& other) {
+  static_cast<Reference<Function>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline FunctionReference::FunctionReference(FunctionReference&& other)
+    : Reference<Function>(std::move(other)) {}
+
+inline FunctionReference& FunctionReference::operator=(
+    FunctionReference&& other) {
+  static_cast<Reference<Function>*>(this)->operator=(std::move(other));
+  return *this;
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::operator()(
+    const std::initializer_list<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value()(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    const std::initializer_list<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    const std::vector<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    napi_value recv, const std::initializer_list<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(recv, args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    napi_value recv, const std::vector<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(recv, args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::Call(
+    napi_value recv, size_t argc, const napi_value* args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().Call(recv, argc, args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::MakeCallback(
+    napi_value recv,
+    const std::initializer_list<napi_value>& args,
+    napi_async_context context) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().MakeCallback(recv, args, context);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::MakeCallback(
+    napi_value recv,
+    const std::vector<napi_value>& args,
+    napi_async_context context) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result = Value().MakeCallback(recv, args, context);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Napi::Value> FunctionReference::MakeCallback(
+    napi_value recv,
+    size_t argc,
+    const napi_value* args,
+    napi_async_context context) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Napi::Value> result =
+      Value().MakeCallback(recv, argc, args, context);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()));
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Value();
+  }
+  return scope.Escape(result);
+#endif
+}
+
+inline MaybeOrValue<Object> FunctionReference::New(
+    const std::initializer_list<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Object> result = Value().New(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()).As<Object>());
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Object();
+  }
+  return scope.Escape(result).As<Object>();
+#endif
+}
+
+inline MaybeOrValue<Object> FunctionReference::New(
+    const std::vector<napi_value>& args) const {
+  EscapableHandleScope scope(_env);
+  MaybeOrValue<Object> result = Value().New(args);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()).As<Object>());
+  }
+  return result;
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Object();
+  }
+  return scope.Escape(result).As<Object>();
+#endif
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// CallbackInfo class
+////////////////////////////////////////////////////////////////////////////////
+
+inline CallbackInfo::CallbackInfo(napi_env env, napi_callback_info info)
+    : _env(env),
+      _info(info),
+      _this(nullptr),
+      _dynamicArgs(nullptr),
+      _data(nullptr) {
+  _argc = _staticArgCount;
+  _argv = _staticArgs;
+  napi_status status =
+      napi_get_cb_info(env, info, &_argc, _argv, &_this, &_data);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+
+  if (_argc > _staticArgCount) {
+    // Use either a fixed-size array (on the stack) or a dynamically-allocated
+    // array (on the heap) depending on the number of args.
+    _dynamicArgs = new napi_value[_argc];
+    _argv = _dynamicArgs;
+
+    status = napi_get_cb_info(env, info, &_argc, _argv, nullptr, nullptr);
+    NAPI_THROW_IF_FAILED_VOID(_env, status);
+  }
+}
+
+inline CallbackInfo::~CallbackInfo() {
+  if (_dynamicArgs != nullptr) {
+    delete[] _dynamicArgs;
+  }
+}
+
+inline CallbackInfo::operator napi_callback_info() const {
+  return _info;
+}
+
+inline Value CallbackInfo::NewTarget() const {
+  napi_value newTarget;
+  napi_status status = napi_get_new_target(_env, _info, &newTarget);
+  NAPI_THROW_IF_FAILED(_env, status, Value());
+  return Value(_env, newTarget);
+}
+
+inline bool CallbackInfo::IsConstructCall() const {
+  return !NewTarget().IsEmpty();
+}
+
+inline Napi::Env CallbackInfo::Env() const {
+  return Napi::Env(_env);
+}
+
+inline size_t CallbackInfo::Length() const {
+  return _argc;
+}
+
+inline const Value CallbackInfo::operator[](size_t index) const {
+  return index < _argc ? Value(_env, _argv[index]) : Env().Undefined();
+}
+
+inline Value CallbackInfo::This() const {
+  if (_this == nullptr) {
+    return Env().Undefined();
+  }
+  return Object(_env, _this);
+}
+
+inline void* CallbackInfo::Data() const {
+  return _data;
+}
+
+inline void CallbackInfo::SetData(void* data) {
+  _data = data;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// PropertyDescriptor class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename PropertyDescriptor::GetterCallback Getter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+
+  desc.utf8name = utf8name;
+  desc.getter = details::TemplatedCallback<Getter>;
+  desc.attributes = attributes;
+  desc.data = data;
+
+  return desc;
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    const std::string& utf8name,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor<Getter>(utf8name.c_str(), attributes, data);
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    Name name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+
+  desc.name = name;
+  desc.getter = details::TemplatedCallback<Getter>;
+  desc.attributes = attributes;
+  desc.data = data;
+
+  return desc;
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter,
+          typename PropertyDescriptor::SetterCallback Setter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+
+  desc.utf8name = utf8name;
+  desc.getter = details::TemplatedCallback<Getter>;
+  desc.setter = details::TemplatedVoidCallback<Setter>;
+  desc.attributes = attributes;
+  desc.data = data;
+
+  return desc;
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter,
+          typename PropertyDescriptor::SetterCallback Setter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    const std::string& utf8name,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor<Getter, Setter>(utf8name.c_str(), attributes, data);
+}
+
+template <typename PropertyDescriptor::GetterCallback Getter,
+          typename PropertyDescriptor::SetterCallback Setter>
+PropertyDescriptor PropertyDescriptor::Accessor(
+    Name name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+
+  desc.name = name;
+  desc.getter = details::TemplatedCallback<Getter>;
+  desc.setter = details::TemplatedVoidCallback<Setter>;
+  desc.attributes = attributes;
+  desc.data = data;
+
+  return desc;
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    const char* utf8name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* data) {
+  using CbData = details::CallbackData<Getter, Napi::Value>;
+  auto callbackData = new CbData({getter, data});
+
+  napi_status status = AttachData(env, object, callbackData);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, napi_property_descriptor());
+  }
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    const std::string& utf8name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor(env, object, utf8name.c_str(), getter, attributes, data);
+}
+
+template <typename Getter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    Name name,
+    Getter getter,
+    napi_property_attributes attributes,
+    void* data) {
+  using CbData = details::CallbackData<Getter, Napi::Value>;
+  auto callbackData = new CbData({getter, data});
+
+  napi_status status = AttachData(env, object, callbackData);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, napi_property_descriptor());
+  }
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             CbData::Wrapper,
+                             nullptr,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    const char* utf8name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  using CbData = details::AccessorCallbackData<Getter, Setter>;
+  auto callbackData = new CbData({getter, setter, data});
+
+  napi_status status = AttachData(env, object, callbackData);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, napi_property_descriptor());
+  }
+
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             CbData::GetterWrapper,
+                             CbData::SetterWrapper,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    const std::string& utf8name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  return Accessor(
+      env, object, utf8name.c_str(), getter, setter, attributes, data);
+}
+
+template <typename Getter, typename Setter>
+inline PropertyDescriptor PropertyDescriptor::Accessor(
+    Napi::Env env,
+    Napi::Object object,
+    Name name,
+    Getter getter,
+    Setter setter,
+    napi_property_attributes attributes,
+    void* data) {
+  using CbData = details::AccessorCallbackData<Getter, Setter>;
+  auto callbackData = new CbData({getter, setter, data});
+
+  napi_status status = AttachData(env, object, callbackData);
+  if (status != napi_ok) {
+    delete callbackData;
+    NAPI_THROW_IF_FAILED(env, status, napi_property_descriptor());
+  }
+
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             CbData::GetterWrapper,
+                             CbData::SetterWrapper,
+                             nullptr,
+                             attributes,
+                             callbackData});
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    Napi::Env env,
+    Napi::Object /*object*/,
+    const char* utf8name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* data) {
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             Napi::Function::New(env, cb, utf8name, data),
+                             attributes,
+                             nullptr});
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    Napi::Env env,
+    Napi::Object object,
+    const std::string& utf8name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* data) {
+  return Function(env, object, utf8name.c_str(), cb, attributes, data);
+}
+
+template <typename Callable>
+inline PropertyDescriptor PropertyDescriptor::Function(
+    Napi::Env env,
+    Napi::Object /*object*/,
+    Name name,
+    Callable cb,
+    napi_property_attributes attributes,
+    void* data) {
+  return PropertyDescriptor({nullptr,
+                             name,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             Napi::Function::New(env, cb, nullptr, data),
+                             attributes,
+                             nullptr});
+}
+
+inline PropertyDescriptor PropertyDescriptor::Value(
+    const char* utf8name,
+    napi_value value,
+    napi_property_attributes attributes) {
+  return PropertyDescriptor({utf8name,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             nullptr,
+                             value,
+                             attributes,
+                             nullptr});
+}
+
+inline PropertyDescriptor PropertyDescriptor::Value(
+    const std::string& utf8name,
+    napi_value value,
+    napi_property_attributes attributes) {
+  return Value(utf8name.c_str(), value, attributes);
+}
+
+inline PropertyDescriptor PropertyDescriptor::Value(
+    napi_value name, napi_value value, napi_property_attributes attributes) {
+  return PropertyDescriptor(
+      {nullptr, name, nullptr, nullptr, nullptr, value, attributes, nullptr});
+}
+
+inline PropertyDescriptor PropertyDescriptor::Value(
+    Name name, Napi::Value value, napi_property_attributes attributes) {
+  napi_value nameValue = name;
+  napi_value valueValue = value;
+  return PropertyDescriptor::Value(nameValue, valueValue, attributes);
+}
+
+inline PropertyDescriptor::PropertyDescriptor(napi_property_descriptor desc)
+    : _desc(desc) {}
+
+inline PropertyDescriptor::operator napi_property_descriptor&() {
+  return _desc;
+}
+
+inline PropertyDescriptor::operator const napi_property_descriptor&() const {
+  return _desc;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// InstanceWrap<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline void InstanceWrap<T>::AttachPropData(
+    napi_env env, napi_value value, const napi_property_descriptor* prop) {
+  napi_status status;
+  if (!(prop->attributes & napi_static)) {
+    if (prop->method == T::InstanceVoidMethodCallbackWrapper) {
+      status = Napi::details::AttachData(
+          env, value, static_cast<InstanceVoidMethodCallbackData*>(prop->data));
+      NAPI_THROW_IF_FAILED_VOID(env, status);
+    } else if (prop->method == T::InstanceMethodCallbackWrapper) {
+      status = Napi::details::AttachData(
+          env, value, static_cast<InstanceMethodCallbackData*>(prop->data));
+      NAPI_THROW_IF_FAILED_VOID(env, status);
+    } else if (prop->getter == T::InstanceGetterCallbackWrapper ||
+               prop->setter == T::InstanceSetterCallbackWrapper) {
+      status = Napi::details::AttachData(
+          env, value, static_cast<InstanceAccessorCallbackData*>(prop->data));
+      NAPI_THROW_IF_FAILED_VOID(env, status);
+    }
+  }
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    const char* utf8name,
+    InstanceVoidMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceVoidMethodCallbackData* callbackData =
+      new InstanceVoidMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = T::InstanceVoidMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    const char* utf8name,
+    InstanceMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceMethodCallbackData* callbackData =
+      new InstanceMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = T::InstanceMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    Symbol name,
+    InstanceVoidMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceVoidMethodCallbackData* callbackData =
+      new InstanceVoidMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = T::InstanceVoidMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    Symbol name,
+    InstanceMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceMethodCallbackData* callbackData =
+      new InstanceMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = T::InstanceMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceVoidMethodCallback method>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = details::TemplatedInstanceVoidCallback<T, method>;
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceMethodCallback method>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = details::TemplatedInstanceCallback<T, method>;
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceVoidMethodCallback method>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = details::TemplatedInstanceVoidCallback<T, method>;
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceMethodCallback method>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceMethod(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = details::TemplatedInstanceCallback<T, method>;
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceAccessor(
+    const char* utf8name,
+    InstanceGetterCallback getter,
+    InstanceSetterCallback setter,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceAccessorCallbackData* callbackData =
+      new InstanceAccessorCallbackData({getter, setter, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.getter = getter != nullptr ? T::InstanceGetterCallbackWrapper : nullptr;
+  desc.setter = setter != nullptr ? T::InstanceSetterCallbackWrapper : nullptr;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceAccessor(
+    Symbol name,
+    InstanceGetterCallback getter,
+    InstanceSetterCallback setter,
+    napi_property_attributes attributes,
+    void* data) {
+  InstanceAccessorCallbackData* callbackData =
+      new InstanceAccessorCallbackData({getter, setter, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.getter = getter != nullptr ? T::InstanceGetterCallbackWrapper : nullptr;
+  desc.setter = setter != nullptr ? T::InstanceSetterCallbackWrapper : nullptr;
+  desc.data = callbackData;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceGetterCallback getter,
+          typename InstanceWrap<T>::InstanceSetterCallback setter>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceAccessor(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.getter = details::TemplatedInstanceCallback<T, getter>;
+  desc.setter = This::WrapSetter(This::SetterTag<setter>());
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceGetterCallback getter,
+          typename InstanceWrap<T>::InstanceSetterCallback setter>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceAccessor(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.getter = details::TemplatedInstanceCallback<T, getter>;
+  desc.setter = This::WrapSetter(This::SetterTag<setter>());
+  desc.data = data;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceValue(
+    const char* utf8name,
+    Napi::Value value,
+    napi_property_attributes attributes) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.value = value;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> InstanceWrap<T>::InstanceValue(
+    Symbol name, Napi::Value value, napi_property_attributes attributes) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.value = value;
+  desc.attributes = attributes;
+  return desc;
+}
+
+template <typename T>
+inline napi_value InstanceWrap<T>::InstanceVoidMethodCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback([&] {
+    CallbackInfo callbackInfo(env, info);
+    InstanceVoidMethodCallbackData* callbackData =
+        reinterpret_cast<InstanceVoidMethodCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    T* instance = T::Unwrap(callbackInfo.This().As<Object>());
+    auto cb = callbackData->callback;
+    if (instance) (instance->*cb)(callbackInfo);
+    return nullptr;
+  });
+}
+
+template <typename T>
+inline napi_value InstanceWrap<T>::InstanceMethodCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback([&] {
+    CallbackInfo callbackInfo(env, info);
+    InstanceMethodCallbackData* callbackData =
+        reinterpret_cast<InstanceMethodCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    T* instance = T::Unwrap(callbackInfo.This().As<Object>());
+    auto cb = callbackData->callback;
+    return instance ? (instance->*cb)(callbackInfo) : Napi::Value();
+  });
+}
+
+template <typename T>
+inline napi_value InstanceWrap<T>::InstanceGetterCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback([&] {
+    CallbackInfo callbackInfo(env, info);
+    InstanceAccessorCallbackData* callbackData =
+        reinterpret_cast<InstanceAccessorCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    T* instance = T::Unwrap(callbackInfo.This().As<Object>());
+    auto cb = callbackData->getterCallback;
+    return instance ? (instance->*cb)(callbackInfo) : Napi::Value();
+  });
+}
+
+template <typename T>
+inline napi_value InstanceWrap<T>::InstanceSetterCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback([&] {
+    CallbackInfo callbackInfo(env, info);
+    InstanceAccessorCallbackData* callbackData =
+        reinterpret_cast<InstanceAccessorCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    T* instance = T::Unwrap(callbackInfo.This().As<Object>());
+    auto cb = callbackData->setterCallback;
+    if (instance) (instance->*cb)(callbackInfo, callbackInfo[0]);
+    return nullptr;
+  });
+}
+
+template <typename T>
+template <typename InstanceWrap<T>::InstanceSetterCallback method>
+inline napi_value InstanceWrap<T>::WrappedMethod(
+    napi_env env, napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback([&] {
+    const CallbackInfo cbInfo(env, info);
+    T* instance = T::Unwrap(cbInfo.This().As<Object>());
+    if (instance) (instance->*method)(cbInfo, cbInfo[0]);
+    return nullptr;
+  });
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ObjectWrap<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline ObjectWrap<T>::ObjectWrap(const Napi::CallbackInfo& callbackInfo) {
+  napi_env env = callbackInfo.Env();
+  napi_value wrapper = callbackInfo.This();
+  napi_status status;
+  napi_ref ref;
+  T* instance = static_cast<T*>(this);
+  status = napi_wrap(env, wrapper, instance, FinalizeCallback, nullptr, &ref);
+  NAPI_THROW_IF_FAILED_VOID(env, status);
+
+  Reference<Object>* instanceRef = instance;
+  *instanceRef = Reference<Object>(env, ref);
+}
+
+template <typename T>
+inline ObjectWrap<T>::~ObjectWrap() {
+  // If the JS object still exists at this point, remove the finalizer added
+  // through `napi_wrap()`.
+  if (!IsEmpty()) {
+    Object object = Value();
+    // It is not valid to call `napi_remove_wrap()` with an empty `object`.
+    // This happens e.g. during garbage collection.
+    if (!object.IsEmpty() && _construction_failed) {
+      napi_remove_wrap(Env(), object, nullptr);
+    }
+  }
+}
+
+template <typename T>
+inline T* ObjectWrap<T>::Unwrap(Object wrapper) {
+  void* unwrapped;
+  napi_status status = napi_unwrap(wrapper.Env(), wrapper, &unwrapped);
+  NAPI_THROW_IF_FAILED(wrapper.Env(), status, nullptr);
+  return static_cast<T*>(unwrapped);
+}
+
+template <typename T>
+inline Function ObjectWrap<T>::DefineClass(
+    Napi::Env env,
+    const char* utf8name,
+    const size_t props_count,
+    const napi_property_descriptor* descriptors,
+    void* data) {
+  napi_status status;
+  std::vector<napi_property_descriptor> props(props_count);
+
+  // We copy the descriptors to a local array because before defining the class
+  // we must replace static method property descriptors with value property
+  // descriptors such that the value is a function-valued `napi_value` created
+  // with `CreateFunction()`.
+  //
+  // This replacement could be made for instance methods as well, but V8 aborts
+  // if we do that, because it expects methods defined on the prototype template
+  // to have `FunctionTemplate`s.
+  for (size_t index = 0; index < props_count; index++) {
+    props[index] = descriptors[index];
+    napi_property_descriptor* prop = &props[index];
+    if (prop->method == T::StaticMethodCallbackWrapper) {
+      status =
+          CreateFunction(env,
+                         utf8name,
+                         prop->method,
+                         static_cast<StaticMethodCallbackData*>(prop->data),
+                         &(prop->value));
+      NAPI_THROW_IF_FAILED(env, status, Function());
+      prop->method = nullptr;
+      prop->data = nullptr;
+    } else if (prop->method == T::StaticVoidMethodCallbackWrapper) {
+      status =
+          CreateFunction(env,
+                         utf8name,
+                         prop->method,
+                         static_cast<StaticVoidMethodCallbackData*>(prop->data),
+                         &(prop->value));
+      NAPI_THROW_IF_FAILED(env, status, Function());
+      prop->method = nullptr;
+      prop->data = nullptr;
+    }
+  }
+
+  napi_value value;
+  status = napi_define_class(env,
+                             utf8name,
+                             NAPI_AUTO_LENGTH,
+                             T::ConstructorCallbackWrapper,
+                             data,
+                             props_count,
+                             props.data(),
+                             &value);
+  NAPI_THROW_IF_FAILED(env, status, Function());
+
+  // After defining the class we iterate once more over the property descriptors
+  // and attach the data associated with accessors and instance methods to the
+  // newly created JavaScript class.
+  for (size_t idx = 0; idx < props_count; idx++) {
+    const napi_property_descriptor* prop = &props[idx];
+
+    if (prop->getter == T::StaticGetterCallbackWrapper ||
+        prop->setter == T::StaticSetterCallbackWrapper) {
+      status = Napi::details::AttachData(
+          env, value, static_cast<StaticAccessorCallbackData*>(prop->data));
+      NAPI_THROW_IF_FAILED(env, status, Function());
+    } else {
+      // InstanceWrap<T>::AttachPropData is responsible for attaching the data
+      // of instance methods and accessors.
+      T::AttachPropData(env, value, prop);
+    }
+  }
+
+  return Function(env, value);
+}
+
+template <typename T>
+inline Function ObjectWrap<T>::DefineClass(
+    Napi::Env env,
+    const char* utf8name,
+    const std::initializer_list<ClassPropertyDescriptor<T>>& properties,
+    void* data) {
+  return DefineClass(
+      env,
+      utf8name,
+      properties.size(),
+      reinterpret_cast<const napi_property_descriptor*>(properties.begin()),
+      data);
+}
+
+template <typename T>
+inline Function ObjectWrap<T>::DefineClass(
+    Napi::Env env,
+    const char* utf8name,
+    const std::vector<ClassPropertyDescriptor<T>>& properties,
+    void* data) {
+  return DefineClass(
+      env,
+      utf8name,
+      properties.size(),
+      reinterpret_cast<const napi_property_descriptor*>(properties.data()),
+      data);
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    const char* utf8name,
+    StaticVoidMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticVoidMethodCallbackData* callbackData =
+      new StaticVoidMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = T::StaticVoidMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    const char* utf8name,
+    StaticMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticMethodCallbackData* callbackData =
+      new StaticMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = T::StaticMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    Symbol name,
+    StaticVoidMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticVoidMethodCallbackData* callbackData =
+      new StaticVoidMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = T::StaticVoidMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    Symbol name,
+    StaticMethodCallback method,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticMethodCallbackData* callbackData =
+      new StaticMethodCallbackData({method, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = T::StaticMethodCallbackWrapper;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticVoidMethodCallback method>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = details::TemplatedVoidCallback<method>;
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticVoidMethodCallback method>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = details::TemplatedVoidCallback<method>;
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticMethodCallback method>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.method = details::TemplatedCallback<method>;
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticMethodCallback method>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticMethod(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.method = details::TemplatedCallback<method>;
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticAccessor(
+    const char* utf8name,
+    StaticGetterCallback getter,
+    StaticSetterCallback setter,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticAccessorCallbackData* callbackData =
+      new StaticAccessorCallbackData({getter, setter, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.getter = getter != nullptr ? T::StaticGetterCallbackWrapper : nullptr;
+  desc.setter = setter != nullptr ? T::StaticSetterCallbackWrapper : nullptr;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticAccessor(
+    Symbol name,
+    StaticGetterCallback getter,
+    StaticSetterCallback setter,
+    napi_property_attributes attributes,
+    void* data) {
+  StaticAccessorCallbackData* callbackData =
+      new StaticAccessorCallbackData({getter, setter, data});
+
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.getter = getter != nullptr ? T::StaticGetterCallbackWrapper : nullptr;
+  desc.setter = setter != nullptr ? T::StaticSetterCallbackWrapper : nullptr;
+  desc.data = callbackData;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticGetterCallback getter,
+          typename ObjectWrap<T>::StaticSetterCallback setter>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticAccessor(
+    const char* utf8name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.getter = details::TemplatedCallback<getter>;
+  desc.setter = This::WrapStaticSetter(This::StaticSetterTag<setter>());
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticGetterCallback getter,
+          typename ObjectWrap<T>::StaticSetterCallback setter>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticAccessor(
+    Symbol name, napi_property_attributes attributes, void* data) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.getter = details::TemplatedCallback<getter>;
+  desc.setter = This::WrapStaticSetter(This::StaticSetterTag<setter>());
+  desc.data = data;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticValue(
+    const char* utf8name,
+    Napi::Value value,
+    napi_property_attributes attributes) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.utf8name = utf8name;
+  desc.value = value;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline ClassPropertyDescriptor<T> ObjectWrap<T>::StaticValue(
+    Symbol name, Napi::Value value, napi_property_attributes attributes) {
+  napi_property_descriptor desc = napi_property_descriptor();
+  desc.name = name;
+  desc.value = value;
+  desc.attributes =
+      static_cast<napi_property_attributes>(attributes | napi_static);
+  return desc;
+}
+
+template <typename T>
+inline Value ObjectWrap<T>::OnCalledAsFunction(
+    const Napi::CallbackInfo& callbackInfo) {
+  NAPI_THROW(
+      TypeError::New(callbackInfo.Env(),
+                     "Class constructors cannot be invoked without 'new'"),
+      Napi::Value());
+}
+
+template <typename T>
+inline void ObjectWrap<T>::Finalize(Napi::Env /*env*/) {}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::ConstructorCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  napi_value new_target;
+  napi_status status = napi_get_new_target(env, info, &new_target);
+  if (status != napi_ok) return nullptr;
+
+  bool isConstructCall = (new_target != nullptr);
+  if (!isConstructCall) {
+    return details::WrapCallback(
+        [&] { return T::OnCalledAsFunction(CallbackInfo(env, info)); });
+  }
+
+  napi_value wrapper = details::WrapCallback([&] {
+    CallbackInfo callbackInfo(env, info);
+    T* instance = new T(callbackInfo);
+#ifdef NAPI_CPP_EXCEPTIONS
+    instance->_construction_failed = false;
+#else
+    if (callbackInfo.Env().IsExceptionPending()) {
+      // We need to clear the exception so that removing the wrap might work.
+      Error e = callbackInfo.Env().GetAndClearPendingException();
+      delete instance;
+      e.ThrowAsJavaScriptException();
+    } else {
+      instance->_construction_failed = false;
+    }
+#endif  // NAPI_CPP_EXCEPTIONS
+    return callbackInfo.This();
+  });
+
+  return wrapper;
+}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::StaticVoidMethodCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback([&] {
+    CallbackInfo callbackInfo(env, info);
+    StaticVoidMethodCallbackData* callbackData =
+        reinterpret_cast<StaticVoidMethodCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    callbackData->callback(callbackInfo);
+    return nullptr;
+  });
+}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::StaticMethodCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback([&] {
+    CallbackInfo callbackInfo(env, info);
+    StaticMethodCallbackData* callbackData =
+        reinterpret_cast<StaticMethodCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    return callbackData->callback(callbackInfo);
+  });
+}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::StaticGetterCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback([&] {
+    CallbackInfo callbackInfo(env, info);
+    StaticAccessorCallbackData* callbackData =
+        reinterpret_cast<StaticAccessorCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    return callbackData->getterCallback(callbackInfo);
+  });
+}
+
+template <typename T>
+inline napi_value ObjectWrap<T>::StaticSetterCallbackWrapper(
+    napi_env env, napi_callback_info info) {
+  return details::WrapCallback([&] {
+    CallbackInfo callbackInfo(env, info);
+    StaticAccessorCallbackData* callbackData =
+        reinterpret_cast<StaticAccessorCallbackData*>(callbackInfo.Data());
+    callbackInfo.SetData(callbackData->data);
+    callbackData->setterCallback(callbackInfo, callbackInfo[0]);
+    return nullptr;
+  });
+}
+
+template <typename T>
+inline void ObjectWrap<T>::FinalizeCallback(napi_env env,
+                                            void* data,
+                                            void* /*hint*/) {
+  HandleScope scope(env);
+  T* instance = static_cast<T*>(data);
+  instance->Finalize(Napi::Env(env));
+  delete instance;
+}
+
+template <typename T>
+template <typename ObjectWrap<T>::StaticSetterCallback method>
+inline napi_value ObjectWrap<T>::WrappedMethod(
+    napi_env env, napi_callback_info info) NAPI_NOEXCEPT {
+  return details::WrapCallback([&] {
+    const CallbackInfo cbInfo(env, info);
+    method(cbInfo, cbInfo[0]);
+    return nullptr;
+  });
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// HandleScope class
+////////////////////////////////////////////////////////////////////////////////
+
+inline HandleScope::HandleScope(napi_env env, napi_handle_scope scope)
+    : _env(env), _scope(scope) {}
+
+inline HandleScope::HandleScope(Napi::Env env) : _env(env) {
+  napi_status status = napi_open_handle_scope(_env, &_scope);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline HandleScope::~HandleScope() {
+  napi_status status = napi_close_handle_scope(_env, _scope);
+  NAPI_FATAL_IF_FAILED(
+      status, "HandleScope::~HandleScope", "napi_close_handle_scope");
+}
+
+inline HandleScope::operator napi_handle_scope() const {
+  return _scope;
+}
+
+inline Napi::Env HandleScope::Env() const {
+  return Napi::Env(_env);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// EscapableHandleScope class
+////////////////////////////////////////////////////////////////////////////////
+
+inline EscapableHandleScope::EscapableHandleScope(
+    napi_env env, napi_escapable_handle_scope scope)
+    : _env(env), _scope(scope) {}
+
+inline EscapableHandleScope::EscapableHandleScope(Napi::Env env) : _env(env) {
+  napi_status status = napi_open_escapable_handle_scope(_env, &_scope);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline EscapableHandleScope::~EscapableHandleScope() {
+  napi_status status = napi_close_escapable_handle_scope(_env, _scope);
+  NAPI_FATAL_IF_FAILED(status,
+                       "EscapableHandleScope::~EscapableHandleScope",
+                       "napi_close_escapable_handle_scope");
+}
+
+inline EscapableHandleScope::operator napi_escapable_handle_scope() const {
+  return _scope;
+}
+
+inline Napi::Env EscapableHandleScope::Env() const {
+  return Napi::Env(_env);
+}
+
+inline Value EscapableHandleScope::Escape(napi_value escapee) {
+  napi_value result;
+  napi_status status = napi_escape_handle(_env, _scope, escapee, &result);
+  NAPI_THROW_IF_FAILED(_env, status, Value());
+  return Value(_env, result);
+}
+
+#if (NAPI_VERSION > 2)
+////////////////////////////////////////////////////////////////////////////////
+// CallbackScope class
+////////////////////////////////////////////////////////////////////////////////
+
+inline CallbackScope::CallbackScope(napi_env env, napi_callback_scope scope)
+    : _env(env), _scope(scope) {}
+
+inline CallbackScope::CallbackScope(napi_env env, napi_async_context context)
+    : _env(env) {
+  napi_status status =
+      napi_open_callback_scope(_env, Object::New(env), context, &_scope);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline CallbackScope::~CallbackScope() {
+  napi_status status = napi_close_callback_scope(_env, _scope);
+  NAPI_FATAL_IF_FAILED(
+      status, "CallbackScope::~CallbackScope", "napi_close_callback_scope");
+}
+
+inline CallbackScope::operator napi_callback_scope() const {
+  return _scope;
+}
+
+inline Napi::Env CallbackScope::Env() const {
+  return Napi::Env(_env);
+}
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// AsyncContext class
+////////////////////////////////////////////////////////////////////////////////
+
+inline AsyncContext::AsyncContext(napi_env env, const char* resource_name)
+    : AsyncContext(env, resource_name, Object::New(env)) {}
+
+inline AsyncContext::AsyncContext(napi_env env,
+                                  const char* resource_name,
+                                  const Object& resource)
+    : _env(env), _context(nullptr) {
+  napi_value resource_id;
+  napi_status status = napi_create_string_utf8(
+      _env, resource_name, NAPI_AUTO_LENGTH, &resource_id);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+
+  status = napi_async_init(_env, resource, resource_id, &_context);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline AsyncContext::~AsyncContext() {
+  if (_context != nullptr) {
+    napi_async_destroy(_env, _context);
+    _context = nullptr;
+  }
+}
+
+inline AsyncContext::AsyncContext(AsyncContext&& other) {
+  _env = other._env;
+  other._env = nullptr;
+  _context = other._context;
+  other._context = nullptr;
+}
+
+inline AsyncContext& AsyncContext::operator=(AsyncContext&& other) {
+  _env = other._env;
+  other._env = nullptr;
+  _context = other._context;
+  other._context = nullptr;
+  return *this;
+}
+
+inline AsyncContext::operator napi_async_context() const {
+  return _context;
+}
+
+inline Napi::Env AsyncContext::Env() const {
+  return Napi::Env(_env);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// AsyncWorker class
+////////////////////////////////////////////////////////////////////////////////
+
+#if NAPI_HAS_THREADS
+
+inline AsyncWorker::AsyncWorker(const Function& callback)
+    : AsyncWorker(callback, "generic") {}
+
+inline AsyncWorker::AsyncWorker(const Function& callback,
+                                const char* resource_name)
+    : AsyncWorker(callback, resource_name, Object::New(callback.Env())) {}
+
+inline AsyncWorker::AsyncWorker(const Function& callback,
+                                const char* resource_name,
+                                const Object& resource)
+    : AsyncWorker(
+          Object::New(callback.Env()), callback, resource_name, resource) {}
+
+inline AsyncWorker::AsyncWorker(const Object& receiver,
+                                const Function& callback)
+    : AsyncWorker(receiver, callback, "generic") {}
+
+inline AsyncWorker::AsyncWorker(const Object& receiver,
+                                const Function& callback,
+                                const char* resource_name)
+    : AsyncWorker(
+          receiver, callback, resource_name, Object::New(callback.Env())) {}
+
+inline AsyncWorker::AsyncWorker(const Object& receiver,
+                                const Function& callback,
+                                const char* resource_name,
+                                const Object& resource)
+    : _env(callback.Env()),
+      _receiver(Napi::Persistent(receiver)),
+      _callback(Napi::Persistent(callback)),
+      _suppress_destruct(false) {
+  napi_value resource_id;
+  napi_status status = napi_create_string_latin1(
+      _env, resource_name, NAPI_AUTO_LENGTH, &resource_id);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+
+  status = napi_create_async_work(_env,
+                                  resource,
+                                  resource_id,
+                                  OnAsyncWorkExecute,
+                                  OnAsyncWorkComplete,
+                                  this,
+                                  &_work);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline AsyncWorker::AsyncWorker(Napi::Env env) : AsyncWorker(env, "generic") {}
+
+inline AsyncWorker::AsyncWorker(Napi::Env env, const char* resource_name)
+    : AsyncWorker(env, resource_name, Object::New(env)) {}
+
+inline AsyncWorker::AsyncWorker(Napi::Env env,
+                                const char* resource_name,
+                                const Object& resource)
+    : _env(env), _receiver(), _callback(), _suppress_destruct(false) {
+  napi_value resource_id;
+  napi_status status = napi_create_string_latin1(
+      _env, resource_name, NAPI_AUTO_LENGTH, &resource_id);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+
+  status = napi_create_async_work(_env,
+                                  resource,
+                                  resource_id,
+                                  OnAsyncWorkExecute,
+                                  OnAsyncWorkComplete,
+                                  this,
+                                  &_work);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline AsyncWorker::~AsyncWorker() {
+  if (_work != nullptr) {
+    napi_delete_async_work(_env, _work);
+    _work = nullptr;
+  }
+}
+
+inline void AsyncWorker::Destroy() {
+  delete this;
+}
+
+inline AsyncWorker::operator napi_async_work() const {
+  return _work;
+}
+
+inline Napi::Env AsyncWorker::Env() const {
+  return Napi::Env(_env);
+}
+
+inline void AsyncWorker::Queue() {
+  napi_status status = napi_queue_async_work(_env, _work);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline void AsyncWorker::Cancel() {
+  napi_status status = napi_cancel_async_work(_env, _work);
+  NAPI_THROW_IF_FAILED_VOID(_env, status);
+}
+
+inline ObjectReference& AsyncWorker::Receiver() {
+  return _receiver;
+}
+
+inline FunctionReference& AsyncWorker::Callback() {
+  return _callback;
+}
+
+inline void AsyncWorker::SuppressDestruct() {
+  _suppress_destruct = true;
+}
+
+inline void AsyncWorker::OnOK() {
+  if (!_callback.IsEmpty()) {
+    _callback.Call(_receiver.Value(), GetResult(_callback.Env()));
+  }
+}
+
+inline void AsyncWorker::OnError(const Error& e) {
+  if (!_callback.IsEmpty()) {
+    _callback.Call(_receiver.Value(),
+                   std::initializer_list<napi_value>{e.Value()});
+  }
+}
+
+inline void AsyncWorker::SetError(const std::string& error) {
+  _error = error;
+}
+
+inline std::vector<napi_value> AsyncWorker::GetResult(Napi::Env /*env*/) {
+  return {};
+}
+// The OnAsyncWorkExecute method receives an napi_env argument. However, do NOT
+// use it within this method, as it does not run on the JavaScript thread and
+// must not run any method that would cause JavaScript to run. In practice,
+// this means that almost any use of napi_env will be incorrect.
+inline void AsyncWorker::OnAsyncWorkExecute(napi_env env, void* asyncworker) {
+  AsyncWorker* self = static_cast<AsyncWorker*>(asyncworker);
+  self->OnExecute(env);
+}
+// The OnExecute method receives an napi_env argument. However, do NOT
+// use it within this method, as it does not run on the JavaScript thread and
+// must not run any method that would cause JavaScript to run. In practice,
+// this means that almost any use of napi_env will be incorrect.
+inline void AsyncWorker::OnExecute(Napi::Env /*DO_NOT_USE*/) {
+#ifdef NAPI_CPP_EXCEPTIONS
+  try {
+    Execute();
+  } catch (const std::exception& e) {
+    SetError(e.what());
+  }
+#else   // NAPI_CPP_EXCEPTIONS
+  Execute();
+#endif  // NAPI_CPP_EXCEPTIONS
+}
+
+inline void AsyncWorker::OnAsyncWorkComplete(napi_env env,
+                                             napi_status status,
+                                             void* asyncworker) {
+  AsyncWorker* self = static_cast<AsyncWorker*>(asyncworker);
+  self->OnWorkComplete(env, status);
+}
+inline void AsyncWorker::OnWorkComplete(Napi::Env /*env*/, napi_status status) {
+  if (status != napi_cancelled) {
+    HandleScope scope(_env);
+    details::WrapCallback([&] {
+      if (_error.size() == 0) {
+        OnOK();
+      } else {
+        OnError(Error::New(_env, _error));
+      }
+      return nullptr;
+    });
+  }
+  if (!_suppress_destruct) {
+    Destroy();
+  }
+}
+
+#endif  // NAPI_HAS_THREADS
+
+#if (NAPI_VERSION > 3 && NAPI_HAS_THREADS)
+////////////////////////////////////////////////////////////////////////////////
+// TypedThreadSafeFunction<ContextType,DataType,CallJs> class
+////////////////////////////////////////////////////////////////////////////////
+
+// Starting with NAPI 5, the JavaScript function `func` parameter of
+// `napi_create_threadsafe_function` is optional.
+#if NAPI_VERSION > 4
+// static, with Callback [missing] Resource [missing] Finalizer [missing]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      nullptr,
+                                      nullptr,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      nullptr,
+                                      nullptr,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [missing] Resource [passed] Finalizer [missing]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Object& resource,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      nullptr,
+                                      resource,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      nullptr,
+                                      nullptr,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [missing] Resource [missing] Finalizer [passed]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context,
+    Finalizer finalizeCallback,
+    FinalizerDataType* data) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  napi_status status = napi_create_threadsafe_function(
+      env,
+      nullptr,
+      nullptr,
+      String::From(env, resourceName),
+      maxQueueSize,
+      initialThreadCount,
+      finalizeData,
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext,
+      context,
+      CallJsInternal,
+      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [missing] Resource [passed] Finalizer [passed]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Object& resource,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context,
+    Finalizer finalizeCallback,
+    FinalizerDataType* data) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  napi_status status = napi_create_threadsafe_function(
+      env,
+      nullptr,
+      resource,
+      String::From(env, resourceName),
+      maxQueueSize,
+      initialThreadCount,
+      finalizeData,
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext,
+      context,
+      CallJsInternal,
+      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+#endif
+
+// static, with Callback [passed] Resource [missing] Finalizer [missing]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Function& callback,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      callback,
+                                      nullptr,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      nullptr,
+                                      nullptr,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [passed] Resource [passed] Finalizer [missing]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Function& callback,
+    const Object& resource,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      callback,
+                                      resource,
+                                      String::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      nullptr,
+                                      nullptr,
+                                      context,
+                                      CallJsInternal,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with Callback [passed] Resource [missing] Finalizer [passed]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    const Function& callback,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context,
+    Finalizer finalizeCallback,
+    FinalizerDataType* data) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  napi_status status = napi_create_threadsafe_function(
+      env,
+      callback,
+      nullptr,
+      String::From(env, resourceName),
+      maxQueueSize,
+      initialThreadCount,
+      finalizeData,
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext,
+      context,
+      CallJsInternal,
+      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+// static, with: Callback [passed] Resource [passed] Finalizer [passed]
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+template <typename CallbackType,
+          typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::New(
+    napi_env env,
+    CallbackType callback,
+    const Object& resource,
+    ResourceString resourceName,
+    size_t maxQueueSize,
+    size_t initialThreadCount,
+    ContextType* context,
+    Finalizer finalizeCallback,
+    FinalizerDataType* data) {
+  TypedThreadSafeFunction<ContextType, DataType, CallJs> tsfn;
+
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  napi_status status = napi_create_threadsafe_function(
+      env,
+      details::DefaultCallbackWrapper<
+          CallbackType,
+          TypedThreadSafeFunction<ContextType, DataType, CallJs>>(env,
+                                                                  callback),
+      resource,
+      String::From(env, resourceName),
+      maxQueueSize,
+      initialThreadCount,
+      finalizeData,
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext,
+      context,
+      CallJsInternal,
+      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(
+        env, status, TypedThreadSafeFunction<ContextType, DataType, CallJs>());
+  }
+
+  return tsfn;
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>::
+    TypedThreadSafeFunction()
+    : _tsfn() {}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>::
+    TypedThreadSafeFunction(napi_threadsafe_function tsfn)
+    : _tsfn(tsfn) {}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline TypedThreadSafeFunction<ContextType, DataType, CallJs>::
+operator napi_threadsafe_function() const {
+  return _tsfn;
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::BlockingCall(
+    DataType* data) const {
+  return napi_call_threadsafe_function(_tsfn, data, napi_tsfn_blocking);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::NonBlockingCall(
+    DataType* data) const {
+  return napi_call_threadsafe_function(_tsfn, data, napi_tsfn_nonblocking);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline void TypedThreadSafeFunction<ContextType, DataType, CallJs>::Ref(
+    napi_env env) const {
+  if (_tsfn != nullptr) {
+    napi_status status = napi_ref_threadsafe_function(env, _tsfn);
+    NAPI_THROW_IF_FAILED_VOID(env, status);
+  }
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline void TypedThreadSafeFunction<ContextType, DataType, CallJs>::Unref(
+    napi_env env) const {
+  if (_tsfn != nullptr) {
+    napi_status status = napi_unref_threadsafe_function(env, _tsfn);
+    NAPI_THROW_IF_FAILED_VOID(env, status);
+  }
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::Acquire() const {
+  return napi_acquire_threadsafe_function(_tsfn);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::Release() const {
+  return napi_release_threadsafe_function(_tsfn, napi_tsfn_release);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline napi_status
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::Abort() const {
+  return napi_release_threadsafe_function(_tsfn, napi_tsfn_abort);
+}
+
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+inline ContextType*
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::GetContext() const {
+  void* context;
+  napi_status status = napi_get_threadsafe_function_context(_tsfn, &context);
+  NAPI_FATAL_IF_FAILED(status,
+                       "TypedThreadSafeFunction::GetContext",
+                       "napi_get_threadsafe_function_context");
+  return static_cast<ContextType*>(context);
+}
+
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+void TypedThreadSafeFunction<ContextType, DataType, CallJs>::CallJsInternal(
+    napi_env env, napi_value jsCallback, void* context, void* data) {
+  details::CallJsWrapper<ContextType, DataType, decltype(CallJs), CallJs>(
+      env, jsCallback, context, data);
+}
+
+#if NAPI_VERSION == 4
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+Napi::Function
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::EmptyFunctionFactory(
+    Napi::Env env) {
+  return Napi::Function::New(env, [](const CallbackInfo& cb) {});
+}
+
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+Napi::Function
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::FunctionOrEmpty(
+    Napi::Env env, Napi::Function& callback) {
+  if (callback.IsEmpty()) {
+    return EmptyFunctionFactory(env);
+  }
+  return callback;
+}
+
+#else
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+std::nullptr_t
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::EmptyFunctionFactory(
+    Napi::Env /*env*/) {
+  return nullptr;
+}
+
+// static
+template <typename ContextType,
+          typename DataType,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*)>
+Napi::Function
+TypedThreadSafeFunction<ContextType, DataType, CallJs>::FunctionOrEmpty(
+    Napi::Env /*env*/, Napi::Function& callback) {
+  return callback;
+}
+
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// ThreadSafeFunction class
+////////////////////////////////////////////////////////////////////////////////
+
+// static
+template <typename ResourceString>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount) {
+  return New(
+      env, callback, Object(), resourceName, maxQueueSize, initialThreadCount);
+}
+
+// static
+template <typename ResourceString, typename ContextType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             context);
+}
+
+// static
+template <typename ResourceString, typename Finalizer>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  Finalizer finalizeCallback) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             finalizeCallback);
+}
+
+// static
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             finalizeCallback,
+             data);
+}
+
+// static
+template <typename ResourceString, typename ContextType, typename Finalizer>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             context,
+             finalizeCallback);
+}
+
+// static
+template <typename ResourceString,
+          typename ContextType,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data) {
+  return New(env,
+             callback,
+             Object(),
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             context,
+             finalizeCallback,
+             data);
+}
+
+// static
+template <typename ResourceString>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount) {
+  return New(env,
+             callback,
+             resource,
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             static_cast<void*>(nullptr) /* context */);
+}
+
+// static
+template <typename ResourceString, typename ContextType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context) {
+  return New(env,
+             callback,
+             resource,
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             context,
+             [](Env, ContextType*) {} /* empty finalizer */);
+}
+
+// static
+template <typename ResourceString, typename Finalizer>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  Finalizer finalizeCallback) {
+  return New(env,
+             callback,
+             resource,
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             static_cast<void*>(nullptr) /* context */,
+             finalizeCallback,
+             static_cast<void*>(nullptr) /* data */,
+             details::ThreadSafeFinalize<void, Finalizer>::Wrapper);
+}
+
+// static
+template <typename ResourceString,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data) {
+  return New(env,
+             callback,
+             resource,
+             resourceName,
+             maxQueueSize,
+             initialThreadCount,
+             static_cast<void*>(nullptr) /* context */,
+             finalizeCallback,
+             data,
+             details::ThreadSafeFinalize<void, Finalizer, FinalizerDataType>::
+                 FinalizeWrapperWithData);
+}
+
+// static
+template <typename ResourceString, typename ContextType, typename Finalizer>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback) {
+  return New(
+      env,
+      callback,
+      resource,
+      resourceName,
+      maxQueueSize,
+      initialThreadCount,
+      context,
+      finalizeCallback,
+      static_cast<void*>(nullptr) /* data */,
+      details::ThreadSafeFinalize<ContextType,
+                                  Finalizer>::FinalizeWrapperWithContext);
+}
+
+// static
+template <typename ResourceString,
+          typename ContextType,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data) {
+  return New(
+      env,
+      callback,
+      resource,
+      resourceName,
+      maxQueueSize,
+      initialThreadCount,
+      context,
+      finalizeCallback,
+      data,
+      details::ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>::
+          FinalizeFinalizeWrapperWithDataAndContext);
+}
+
+inline ThreadSafeFunction::ThreadSafeFunction() : _tsfn() {}
+
+inline ThreadSafeFunction::ThreadSafeFunction(napi_threadsafe_function tsfn)
+    : _tsfn(tsfn) {}
+
+inline ThreadSafeFunction::operator napi_threadsafe_function() const {
+  return _tsfn;
+}
+
+inline napi_status ThreadSafeFunction::BlockingCall() const {
+  return CallInternal(nullptr, napi_tsfn_blocking);
+}
+
+template <>
+inline napi_status ThreadSafeFunction::BlockingCall(void* data) const {
+  return napi_call_threadsafe_function(_tsfn, data, napi_tsfn_blocking);
+}
+
+template <typename Callback>
+inline napi_status ThreadSafeFunction::BlockingCall(Callback callback) const {
+  return CallInternal(new CallbackWrapper(callback), napi_tsfn_blocking);
+}
+
+template <typename DataType, typename Callback>
+inline napi_status ThreadSafeFunction::BlockingCall(DataType* data,
+                                                    Callback callback) const {
+  auto wrapper = [data, callback](Env env, Function jsCallback) {
+    callback(env, jsCallback, data);
+  };
+  return CallInternal(new CallbackWrapper(wrapper), napi_tsfn_blocking);
+}
+
+inline napi_status ThreadSafeFunction::NonBlockingCall() const {
+  return CallInternal(nullptr, napi_tsfn_nonblocking);
+}
+
+template <>
+inline napi_status ThreadSafeFunction::NonBlockingCall(void* data) const {
+  return napi_call_threadsafe_function(_tsfn, data, napi_tsfn_nonblocking);
+}
+
+template <typename Callback>
+inline napi_status ThreadSafeFunction::NonBlockingCall(
+    Callback callback) const {
+  return CallInternal(new CallbackWrapper(callback), napi_tsfn_nonblocking);
+}
+
+template <typename DataType, typename Callback>
+inline napi_status ThreadSafeFunction::NonBlockingCall(
+    DataType* data, Callback callback) const {
+  auto wrapper = [data, callback](Env env, Function jsCallback) {
+    callback(env, jsCallback, data);
+  };
+  return CallInternal(new CallbackWrapper(wrapper), napi_tsfn_nonblocking);
+}
+
+inline void ThreadSafeFunction::Ref(napi_env env) const {
+  if (_tsfn != nullptr) {
+    napi_status status = napi_ref_threadsafe_function(env, _tsfn);
+    NAPI_THROW_IF_FAILED_VOID(env, status);
+  }
+}
+
+inline void ThreadSafeFunction::Unref(napi_env env) const {
+  if (_tsfn != nullptr) {
+    napi_status status = napi_unref_threadsafe_function(env, _tsfn);
+    NAPI_THROW_IF_FAILED_VOID(env, status);
+  }
+}
+
+inline napi_status ThreadSafeFunction::Acquire() const {
+  return napi_acquire_threadsafe_function(_tsfn);
+}
+
+inline napi_status ThreadSafeFunction::Release() const {
+  return napi_release_threadsafe_function(_tsfn, napi_tsfn_release);
+}
+
+inline napi_status ThreadSafeFunction::Abort() const {
+  return napi_release_threadsafe_function(_tsfn, napi_tsfn_abort);
+}
+
+inline ThreadSafeFunction::ConvertibleContext ThreadSafeFunction::GetContext()
+    const {
+  void* context;
+  napi_status status = napi_get_threadsafe_function_context(_tsfn, &context);
+  NAPI_FATAL_IF_FAILED(status,
+                       "ThreadSafeFunction::GetContext",
+                       "napi_get_threadsafe_function_context");
+  return ConvertibleContext({context});
+}
+
+// static
+template <typename ResourceString,
+          typename ContextType,
+          typename Finalizer,
+          typename FinalizerDataType>
+inline ThreadSafeFunction ThreadSafeFunction::New(napi_env env,
+                                                  const Function& callback,
+                                                  const Object& resource,
+                                                  ResourceString resourceName,
+                                                  size_t maxQueueSize,
+                                                  size_t initialThreadCount,
+                                                  ContextType* context,
+                                                  Finalizer finalizeCallback,
+                                                  FinalizerDataType* data,
+                                                  napi_finalize wrapper) {
+  static_assert(details::can_make_string<ResourceString>::value ||
+                    std::is_convertible<ResourceString, napi_value>::value,
+                "Resource name should be convertible to the string type");
+
+  ThreadSafeFunction tsfn;
+  auto* finalizeData = new details::
+      ThreadSafeFinalize<ContextType, Finalizer, FinalizerDataType>(
+          {data, finalizeCallback});
+  napi_status status =
+      napi_create_threadsafe_function(env,
+                                      callback,
+                                      resource,
+                                      Value::From(env, resourceName),
+                                      maxQueueSize,
+                                      initialThreadCount,
+                                      finalizeData,
+                                      wrapper,
+                                      context,
+                                      CallJS,
+                                      &tsfn._tsfn);
+  if (status != napi_ok) {
+    delete finalizeData;
+    NAPI_THROW_IF_FAILED(env, status, ThreadSafeFunction());
+  }
+
+  return tsfn;
+}
+
+inline napi_status ThreadSafeFunction::CallInternal(
+    CallbackWrapper* callbackWrapper,
+    napi_threadsafe_function_call_mode mode) const {
+  napi_status status =
+      napi_call_threadsafe_function(_tsfn, callbackWrapper, mode);
+  if (status != napi_ok && callbackWrapper != nullptr) {
+    delete callbackWrapper;
+  }
+
+  return status;
+}
+
+// static
+inline void ThreadSafeFunction::CallJS(napi_env env,
+                                       napi_value jsCallback,
+                                       void* /* context */,
+                                       void* data) {
+  if (env == nullptr && jsCallback == nullptr) {
+    return;
+  }
+
+  details::WrapVoidCallback([&]() {
+    if (data != nullptr) {
+      auto* callbackWrapper = static_cast<CallbackWrapper*>(data);
+      (*callbackWrapper)(env, Function(env, jsCallback));
+      delete callbackWrapper;
+    } else if (jsCallback != nullptr) {
+      Function(env, jsCallback).Call({});
+    }
+  });
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Async Progress Worker Base class
+////////////////////////////////////////////////////////////////////////////////
+template <typename DataType>
+inline AsyncProgressWorkerBase<DataType>::AsyncProgressWorkerBase(
+    const Object& receiver,
+    const Function& callback,
+    const char* resource_name,
+    const Object& resource,
+    size_t queue_size)
+    : AsyncWorker(receiver, callback, resource_name, resource) {
+  // Fill all possible arguments to work around ambiguous
+  // ThreadSafeFunction::New signatures.
+  _tsfn = ThreadSafeFunction::New(callback.Env(),
+                                  callback,
+                                  resource,
+                                  resource_name,
+                                  queue_size,
+                                  /** initialThreadCount */ 1,
+                                  /** context */ this,
+                                  OnThreadSafeFunctionFinalize,
+                                  /** finalizeData */ this);
+}
+
+#if NAPI_VERSION > 4
+template <typename DataType>
+inline AsyncProgressWorkerBase<DataType>::AsyncProgressWorkerBase(
+    Napi::Env env,
+    const char* resource_name,
+    const Object& resource,
+    size_t queue_size)
+    : AsyncWorker(env, resource_name, resource) {
+  // TODO: Once the changes to make the callback optional for threadsafe
+  // functions are available on all versions we can remove the dummy Function
+  // here.
+  Function callback;
+  // Fill all possible arguments to work around ambiguous
+  // ThreadSafeFunction::New signatures.
+  _tsfn = ThreadSafeFunction::New(env,
+                                  callback,
+                                  resource,
+                                  resource_name,
+                                  queue_size,
+                                  /** initialThreadCount */ 1,
+                                  /** context */ this,
+                                  OnThreadSafeFunctionFinalize,
+                                  /** finalizeData */ this);
+}
+#endif
+
+template <typename DataType>
+inline AsyncProgressWorkerBase<DataType>::~AsyncProgressWorkerBase() {
+  // Abort pending tsfn call.
+  // Don't send progress events after we've already completed.
+  // It's ok to call ThreadSafeFunction::Abort and ThreadSafeFunction::Release
+  // duplicated.
+  _tsfn.Abort();
+}
+
+template <typename DataType>
+inline void AsyncProgressWorkerBase<DataType>::OnAsyncWorkProgress(
+    Napi::Env /* env */, Napi::Function /* jsCallback */, void* data) {
+  ThreadSafeData* tsd = static_cast<ThreadSafeData*>(data);
+  tsd->asyncprogressworker()->OnWorkProgress(tsd->data());
+  delete tsd;
+}
+
+template <typename DataType>
+inline napi_status AsyncProgressWorkerBase<DataType>::NonBlockingCall(
+    DataType* data) {
+  auto tsd = new AsyncProgressWorkerBase::ThreadSafeData(this, data);
+  auto ret = _tsfn.NonBlockingCall(tsd, OnAsyncWorkProgress);
+  if (ret != napi_ok) {
+    delete tsd;
+  }
+  return ret;
+}
+
+template <typename DataType>
+inline void AsyncProgressWorkerBase<DataType>::OnWorkComplete(
+    Napi::Env /* env */, napi_status status) {
+  _work_completed = true;
+  _complete_status = status;
+  _tsfn.Release();
+}
+
+template <typename DataType>
+inline void AsyncProgressWorkerBase<DataType>::OnThreadSafeFunctionFinalize(
+    Napi::Env env, void* /* data */, AsyncProgressWorkerBase* context) {
+  if (context->_work_completed) {
+    context->AsyncWorker::OnWorkComplete(env, context->_complete_status);
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Async Progress Worker class
+////////////////////////////////////////////////////////////////////////////////
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Function& callback)
+    : AsyncProgressWorker(callback, "generic") {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Function& callback,
+                                                   const char* resource_name)
+    : AsyncProgressWorker(
+          callback, resource_name, Object::New(callback.Env())) {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Function& callback,
+                                                   const char* resource_name,
+                                                   const Object& resource)
+    : AsyncProgressWorker(
+          Object::New(callback.Env()), callback, resource_name, resource) {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Object& receiver,
+                                                   const Function& callback)
+    : AsyncProgressWorker(receiver, callback, "generic") {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Object& receiver,
+                                                   const Function& callback,
+                                                   const char* resource_name)
+    : AsyncProgressWorker(
+          receiver, callback, resource_name, Object::New(callback.Env())) {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(const Object& receiver,
+                                                   const Function& callback,
+                                                   const char* resource_name,
+                                                   const Object& resource)
+    : AsyncProgressWorkerBase(receiver, callback, resource_name, resource),
+      _asyncdata(nullptr),
+      _asyncsize(0),
+      _signaled(false) {}
+
+#if NAPI_VERSION > 4
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(Napi::Env env)
+    : AsyncProgressWorker(env, "generic") {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(Napi::Env env,
+                                                   const char* resource_name)
+    : AsyncProgressWorker(env, resource_name, Object::New(env)) {}
+
+template <class T>
+inline AsyncProgressWorker<T>::AsyncProgressWorker(Napi::Env env,
+                                                   const char* resource_name,
+                                                   const Object& resource)
+    : AsyncProgressWorkerBase(env, resource_name, resource),
+      _asyncdata(nullptr),
+      _asyncsize(0) {}
+#endif
+
+template <class T>
+inline AsyncProgressWorker<T>::~AsyncProgressWorker() {
+  {
+    std::lock_guard<std::mutex> lock(this->_mutex);
+    _asyncdata = nullptr;
+    _asyncsize = 0;
+  }
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::Execute() {
+  ExecutionProgress progress(this);
+  Execute(progress);
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::OnWorkProgress(void*) {
+  T* data;
+  size_t size;
+  bool signaled;
+  {
+    std::lock_guard<std::mutex> lock(this->_mutex);
+    data = this->_asyncdata;
+    size = this->_asyncsize;
+    signaled = this->_signaled;
+    this->_asyncdata = nullptr;
+    this->_asyncsize = 0;
+    this->_signaled = false;
+  }
+
+  /**
+   * The callback of ThreadSafeFunction is not been invoked immediately on the
+   * callback of uv_async_t (uv io poll), rather the callback of TSFN is
+   * invoked on the right next uv idle callback. There are chances that during
+   * the deferring the signal of uv_async_t is been sent again, i.e. potential
+   * not coalesced two calls of the TSFN callback.
+   */
+  if (data == nullptr && !signaled) {
+    return;
+  }
+
+  this->OnProgress(data, size);
+  delete[] data;
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::SendProgress_(const T* data, size_t count) {
+  T* new_data = new T[count];
+  std::copy(data, data + count, new_data);
+
+  T* old_data;
+  {
+    std::lock_guard<std::mutex> lock(this->_mutex);
+    old_data = _asyncdata;
+    _asyncdata = new_data;
+    _asyncsize = count;
+    _signaled = false;
+  }
+  this->NonBlockingCall(nullptr);
+
+  delete[] old_data;
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::Signal() {
+  {
+    std::lock_guard<std::mutex> lock(this->_mutex);
+    _signaled = true;
+  }
+  this->NonBlockingCall(static_cast<T*>(nullptr));
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::ExecutionProgress::Signal() const {
+  this->_worker->Signal();
+}
+
+template <class T>
+inline void AsyncProgressWorker<T>::ExecutionProgress::Send(
+    const T* data, size_t count) const {
+  _worker->SendProgress_(data, count);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Async Progress Queue Worker class
+////////////////////////////////////////////////////////////////////////////////
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Function& callback)
+    : AsyncProgressQueueWorker(callback, "generic") {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Function& callback, const char* resource_name)
+    : AsyncProgressQueueWorker(
+          callback, resource_name, Object::New(callback.Env())) {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Function& callback, const char* resource_name, const Object& resource)
+    : AsyncProgressQueueWorker(
+          Object::New(callback.Env()), callback, resource_name, resource) {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Object& receiver, const Function& callback)
+    : AsyncProgressQueueWorker(receiver, callback, "generic") {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Object& receiver, const Function& callback, const char* resource_name)
+    : AsyncProgressQueueWorker(
+          receiver, callback, resource_name, Object::New(callback.Env())) {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    const Object& receiver,
+    const Function& callback,
+    const char* resource_name,
+    const Object& resource)
+    : AsyncProgressWorkerBase<std::pair<T*, size_t>>(
+          receiver,
+          callback,
+          resource_name,
+          resource,
+          /** unlimited queue size */ 0) {}
+
+#if NAPI_VERSION > 4
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(Napi::Env env)
+    : AsyncProgressQueueWorker(env, "generic") {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    Napi::Env env, const char* resource_name)
+    : AsyncProgressQueueWorker(env, resource_name, Object::New(env)) {}
+
+template <class T>
+inline AsyncProgressQueueWorker<T>::AsyncProgressQueueWorker(
+    Napi::Env env, const char* resource_name, const Object& resource)
+    : AsyncProgressWorkerBase<std::pair<T*, size_t>>(
+          env, resource_name, resource, /** unlimited queue size */ 0) {}
+#endif
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::Execute() {
+  ExecutionProgress progress(this);
+  Execute(progress);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::OnWorkProgress(
+    std::pair<T*, size_t>* datapair) {
+  if (datapair == nullptr) {
+    return;
+  }
+
+  T* data = datapair->first;
+  size_t size = datapair->second;
+
+  this->OnProgress(data, size);
+  delete datapair;
+  delete[] data;
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::SendProgress_(const T* data,
+                                                       size_t count) {
+  T* new_data = new T[count];
+  std::copy(data, data + count, new_data);
+
+  auto pair = new std::pair<T*, size_t>(new_data, count);
+  this->NonBlockingCall(pair);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::Signal() const {
+  this->SendProgress_(static_cast<T*>(nullptr), 0);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::OnWorkComplete(Napi::Env env,
+                                                        napi_status status) {
+  // Draining queued items in TSFN.
+  AsyncProgressWorkerBase<std::pair<T*, size_t>>::OnWorkComplete(env, status);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::ExecutionProgress::Signal() const {
+  _worker->SendProgress_(static_cast<T*>(nullptr), 0);
+}
+
+template <class T>
+inline void AsyncProgressQueueWorker<T>::ExecutionProgress::Send(
+    const T* data, size_t count) const {
+  _worker->SendProgress_(data, count);
+}
+#endif  // NAPI_VERSION > 3 && NAPI_HAS_THREADS
+
+////////////////////////////////////////////////////////////////////////////////
+// Memory Management class
+////////////////////////////////////////////////////////////////////////////////
+
+inline int64_t MemoryManagement::AdjustExternalMemory(Env env,
+                                                      int64_t change_in_bytes) {
+  int64_t result;
+  napi_status status =
+      napi_adjust_external_memory(env, change_in_bytes, &result);
+  NAPI_THROW_IF_FAILED(env, status, 0);
+  return result;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Version Management class
+////////////////////////////////////////////////////////////////////////////////
+
+inline uint32_t VersionManagement::GetNapiVersion(Env env) {
+  uint32_t result;
+  napi_status status = napi_get_version(env, &result);
+  NAPI_THROW_IF_FAILED(env, status, 0);
+  return result;
+}
+
+inline const napi_node_version* VersionManagement::GetNodeVersion(Env env) {
+  const napi_node_version* result;
+  napi_status status = napi_get_node_version(env, &result);
+  NAPI_THROW_IF_FAILED(env, status, 0);
+  return result;
+}
+
+#if NAPI_VERSION > 5
+////////////////////////////////////////////////////////////////////////////////
+// Addon<T> class
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+inline Object Addon<T>::Init(Env env, Object exports) {
+  T* addon = new T(env, exports);
+  env.SetInstanceData(addon);
+  return addon->entry_point_;
+}
+
+template <typename T>
+inline T* Addon<T>::Unwrap(Object wrapper) {
+  return wrapper.Env().GetInstanceData<T>();
+}
+
+template <typename T>
+inline void Addon<T>::DefineAddon(
+    Object exports, const std::initializer_list<AddonProp>& props) {
+  DefineProperties(exports, props);
+  entry_point_ = exports;
+}
+
+template <typename T>
+inline Napi::Object Addon<T>::DefineProperties(
+    Object object, const std::initializer_list<AddonProp>& props) {
+  const napi_property_descriptor* properties =
+      reinterpret_cast<const napi_property_descriptor*>(props.begin());
+  size_t size = props.size();
+  napi_status status =
+      napi_define_properties(object.Env(), object, size, properties);
+  NAPI_THROW_IF_FAILED(object.Env(), status, object);
+  for (size_t idx = 0; idx < size; idx++)
+    T::AttachPropData(object.Env(), object, &properties[idx]);
+  return object;
+}
+#endif  // NAPI_VERSION > 5
+
+#if NAPI_VERSION > 2
+template <typename Hook, typename Arg>
+Env::CleanupHook<Hook, Arg> Env::AddCleanupHook(Hook hook, Arg* arg) {
+  return CleanupHook<Hook, Arg>(*this, hook, arg);
+}
+
+template <typename Hook>
+Env::CleanupHook<Hook> Env::AddCleanupHook(Hook hook) {
+  return CleanupHook<Hook>(*this, hook);
+}
+
+template <typename Hook, typename Arg>
+Env::CleanupHook<Hook, Arg>::CleanupHook() {
+  data = nullptr;
+}
+
+template <typename Hook, typename Arg>
+Env::CleanupHook<Hook, Arg>::CleanupHook(Napi::Env env, Hook hook)
+    : wrapper(Env::CleanupHook<Hook, Arg>::Wrapper) {
+  data = new CleanupData{std::move(hook), nullptr};
+  napi_status status = napi_add_env_cleanup_hook(env, wrapper, data);
+  if (status != napi_ok) {
+    delete data;
+    data = nullptr;
+  }
+}
+
+template <typename Hook, typename Arg>
+Env::CleanupHook<Hook, Arg>::CleanupHook(Napi::Env env, Hook hook, Arg* arg)
+    : wrapper(Env::CleanupHook<Hook, Arg>::WrapperWithArg) {
+  data = new CleanupData{std::move(hook), arg};
+  napi_status status = napi_add_env_cleanup_hook(env, wrapper, data);
+  if (status != napi_ok) {
+    delete data;
+    data = nullptr;
+  }
+}
+
+template <class Hook, class Arg>
+bool Env::CleanupHook<Hook, Arg>::Remove(Env env) {
+  napi_status status = napi_remove_env_cleanup_hook(env, wrapper, data);
+  delete data;
+  data = nullptr;
+  return status == napi_ok;
+}
+
+template <class Hook, class Arg>
+bool Env::CleanupHook<Hook, Arg>::IsEmpty() const {
+  return data == nullptr;
+}
+#endif  // NAPI_VERSION > 2
+
+#ifdef NAPI_CPP_CUSTOM_NAMESPACE
+}  // namespace NAPI_CPP_CUSTOM_NAMESPACE
+#endif
+
+}  // namespace Napi
+
+#endif  // SRC_NAPI_INL_H_
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/napi.h b/server/node_modules/sqlite3/node_modules/node-addon-api/napi.h
new file mode 100644
index 0000000..9f20cb8
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/napi.h
@@ -0,0 +1,3201 @@
+#ifndef SRC_NAPI_H_
+#define SRC_NAPI_H_
+
+#ifndef NAPI_HAS_THREADS
+#if !defined(__wasm__) || (defined(__EMSCRIPTEN_PTHREADS__) ||                 \
+                           (defined(__wasi__) && defined(_REENTRANT)))
+#define NAPI_HAS_THREADS 1
+#else
+#define NAPI_HAS_THREADS 0
+#endif
+#endif
+
+#include <node_api.h>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#if NAPI_HAS_THREADS
+#include <mutex>
+#endif  // NAPI_HAS_THREADS
+#include <string>
+#include <vector>
+
+// VS2015 RTM has bugs with constexpr, so require min of VS2015 Update 3 (known
+// good version)
+#if !defined(_MSC_VER) || _MSC_FULL_VER >= 190024210
+#define NAPI_HAS_CONSTEXPR 1
+#endif
+
+// VS2013 does not support char16_t literal strings, so we'll work around it
+// using wchar_t strings and casting them. This is safe as long as the character
+// sizes are the same.
+#if defined(_MSC_VER) && _MSC_VER <= 1800
+static_assert(sizeof(char16_t) == sizeof(wchar_t),
+              "Size mismatch between char16_t and wchar_t");
+#define NAPI_WIDE_TEXT(x) reinterpret_cast<char16_t*>(L##x)
+#else
+#define NAPI_WIDE_TEXT(x) u##x
+#endif
+
+// If C++ exceptions are not explicitly enabled or disabled, enable them
+// if exceptions were enabled in the compiler settings.
+#if !defined(NAPI_CPP_EXCEPTIONS) && !defined(NAPI_DISABLE_CPP_EXCEPTIONS)
+#if defined(_CPPUNWIND) || defined(__EXCEPTIONS)
+#define NAPI_CPP_EXCEPTIONS
+#else
+#error Exception support not detected. \
+      Define either NAPI_CPP_EXCEPTIONS or NAPI_DISABLE_CPP_EXCEPTIONS.
+#endif
+#endif
+
+// If C++ NAPI_CPP_EXCEPTIONS are enabled, NODE_ADDON_API_ENABLE_MAYBE should
+// not be set
+#if defined(NAPI_CPP_EXCEPTIONS) && defined(NODE_ADDON_API_ENABLE_MAYBE)
+#error NODE_ADDON_API_ENABLE_MAYBE should not be set when \
+    NAPI_CPP_EXCEPTIONS is defined.
+#endif
+
+#ifdef _NOEXCEPT
+#define NAPI_NOEXCEPT _NOEXCEPT
+#else
+#define NAPI_NOEXCEPT noexcept
+#endif
+
+#ifdef NAPI_CPP_EXCEPTIONS
+
+// When C++ exceptions are enabled, Errors are thrown directly. There is no need
+// to return anything after the throw statements. The variadic parameter is an
+// optional return value that is ignored.
+// We need _VOID versions of the macros to avoid warnings resulting from
+// leaving the NAPI_THROW_* `...` argument empty.
+
+#define NAPI_THROW(e, ...) throw e
+#define NAPI_THROW_VOID(e) throw e
+
+#define NAPI_THROW_IF_FAILED(env, status, ...)                                 \
+  if ((status) != napi_ok) throw Napi::Error::New(env);
+
+#define NAPI_THROW_IF_FAILED_VOID(env, status)                                 \
+  if ((status) != napi_ok) throw Napi::Error::New(env);
+
+#else  // NAPI_CPP_EXCEPTIONS
+
+// When C++ exceptions are disabled, Errors are thrown as JavaScript exceptions,
+// which are pending until the callback returns to JS.  The variadic parameter
+// is an optional return value; usually it is an empty result.
+// We need _VOID versions of the macros to avoid warnings resulting from
+// leaving the NAPI_THROW_* `...` argument empty.
+
+#define NAPI_THROW(e, ...)                                                     \
+  do {                                                                         \
+    (e).ThrowAsJavaScriptException();                                          \
+    return __VA_ARGS__;                                                        \
+  } while (0)
+
+#define NAPI_THROW_VOID(e)                                                     \
+  do {                                                                         \
+    (e).ThrowAsJavaScriptException();                                          \
+    return;                                                                    \
+  } while (0)
+
+#define NAPI_THROW_IF_FAILED(env, status, ...)                                 \
+  if ((status) != napi_ok) {                                                   \
+    Napi::Error::New(env).ThrowAsJavaScriptException();                        \
+    return __VA_ARGS__;                                                        \
+  }
+
+#define NAPI_THROW_IF_FAILED_VOID(env, status)                                 \
+  if ((status) != napi_ok) {                                                   \
+    Napi::Error::New(env).ThrowAsJavaScriptException();                        \
+    return;                                                                    \
+  }
+
+#endif  // NAPI_CPP_EXCEPTIONS
+
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+#define NAPI_MAYBE_THROW_IF_FAILED(env, status, type)                          \
+  NAPI_THROW_IF_FAILED(env, status, Napi::Nothing<type>())
+
+#define NAPI_RETURN_OR_THROW_IF_FAILED(env, status, result, type)              \
+  NAPI_MAYBE_THROW_IF_FAILED(env, status, type);                               \
+  return Napi::Just<type>(result);
+#else
+#define NAPI_MAYBE_THROW_IF_FAILED(env, status, type)                          \
+  NAPI_THROW_IF_FAILED(env, status, type())
+
+#define NAPI_RETURN_OR_THROW_IF_FAILED(env, status, result, type)              \
+  NAPI_MAYBE_THROW_IF_FAILED(env, status, type);                               \
+  return result;
+#endif
+
+#define NAPI_DISALLOW_ASSIGN(CLASS) void operator=(const CLASS&) = delete;
+#define NAPI_DISALLOW_COPY(CLASS) CLASS(const CLASS&) = delete;
+
+#define NAPI_DISALLOW_ASSIGN_COPY(CLASS)                                       \
+  NAPI_DISALLOW_ASSIGN(CLASS)                                                  \
+  NAPI_DISALLOW_COPY(CLASS)
+
+#define NAPI_CHECK(condition, location, message)                               \
+  do {                                                                         \
+    if (!(condition)) {                                                        \
+      Napi::Error::Fatal((location), (message));                               \
+    }                                                                          \
+  } while (0)
+
+#define NAPI_FATAL_IF_FAILED(status, location, message)                        \
+  NAPI_CHECK((status) == napi_ok, location, message)
+
+////////////////////////////////////////////////////////////////////////////////
+/// Node-API C++ Wrapper Classes
+///
+/// These classes wrap the "Node-API" ABI-stable C APIs for Node.js, providing a
+/// C++ object model and C++ exception-handling semantics with low overhead.
+/// The wrappers are all header-only so that they do not affect the ABI.
+////////////////////////////////////////////////////////////////////////////////
+namespace Napi {
+
+#ifdef NAPI_CPP_CUSTOM_NAMESPACE
+// NAPI_CPP_CUSTOM_NAMESPACE can be #define'd per-addon to avoid symbol
+// conflicts between different instances of node-addon-api
+
+// First dummy definition of the namespace to make sure that Napi::(name) still
+// refers to the right things inside this file.
+namespace NAPI_CPP_CUSTOM_NAMESPACE {}
+using namespace NAPI_CPP_CUSTOM_NAMESPACE;
+
+namespace NAPI_CPP_CUSTOM_NAMESPACE {
+#endif
+
+// Forward declarations
+class Env;
+class Value;
+class Boolean;
+class Number;
+#if NAPI_VERSION > 5
+class BigInt;
+#endif  // NAPI_VERSION > 5
+#if (NAPI_VERSION > 4)
+class Date;
+#endif
+class String;
+class Object;
+class Array;
+class ArrayBuffer;
+class Function;
+class Error;
+class PropertyDescriptor;
+class CallbackInfo;
+class TypedArray;
+template <typename T>
+class TypedArrayOf;
+
+using Int8Array =
+    TypedArrayOf<int8_t>;  ///< Typed-array of signed 8-bit integers
+using Uint8Array =
+    TypedArrayOf<uint8_t>;  ///< Typed-array of unsigned 8-bit integers
+using Int16Array =
+    TypedArrayOf<int16_t>;  ///< Typed-array of signed 16-bit integers
+using Uint16Array =
+    TypedArrayOf<uint16_t>;  ///< Typed-array of unsigned 16-bit integers
+using Int32Array =
+    TypedArrayOf<int32_t>;  ///< Typed-array of signed 32-bit integers
+using Uint32Array =
+    TypedArrayOf<uint32_t>;  ///< Typed-array of unsigned 32-bit integers
+using Float32Array =
+    TypedArrayOf<float>;  ///< Typed-array of 32-bit floating-point values
+using Float64Array =
+    TypedArrayOf<double>;  ///< Typed-array of 64-bit floating-point values
+#if NAPI_VERSION > 5
+using BigInt64Array =
+    TypedArrayOf<int64_t>;  ///< Typed array of signed 64-bit integers
+using BigUint64Array =
+    TypedArrayOf<uint64_t>;  ///< Typed array of unsigned 64-bit integers
+#endif                       // NAPI_VERSION > 5
+
+/// Defines the signature of a Node-API C++ module's registration callback
+/// (init) function.
+using ModuleRegisterCallback = Object (*)(Env env, Object exports);
+
+class MemoryManagement;
+
+/// A simple Maybe type, representing an object which may or may not have a
+/// value.
+///
+/// If an API method returns a Maybe<>, the API method can potentially fail
+/// either because an exception is thrown, or because an exception is pending,
+/// e.g. because a previous API call threw an exception that hasn't been
+/// caught yet. In that case, a "Nothing" value is returned.
+template <class T>
+class Maybe {
+ public:
+  bool IsNothing() const;
+  bool IsJust() const;
+
+  /// Short-hand for Unwrap(), which doesn't return a value. Could be used
+  /// where the actual value of the Maybe is not needed like Object::Set.
+  /// If this Maybe is nothing (empty), node-addon-api will crash the
+  /// process.
+  void Check() const;
+
+  /// Return the value of type T contained in the Maybe. If this Maybe is
+  /// nothing (empty), node-addon-api will crash the process.
+  T Unwrap() const;
+
+  /// Return the value of type T contained in the Maybe, or using a default
+  /// value if this Maybe is nothing (empty).
+  T UnwrapOr(const T& default_value) const;
+
+  /// Converts this Maybe to a value of type T in the out. If this Maybe is
+  /// nothing (empty), `false` is returned and `out` is left untouched.
+  bool UnwrapTo(T* out) const;
+
+  bool operator==(const Maybe& other) const;
+  bool operator!=(const Maybe& other) const;
+
+ private:
+  Maybe();
+  explicit Maybe(const T& t);
+
+  bool _has_value;
+  T _value;
+
+  template <class U>
+  friend Maybe<U> Nothing();
+  template <class U>
+  friend Maybe<U> Just(const U& u);
+};
+
+template <class T>
+inline Maybe<T> Nothing();
+
+template <class T>
+inline Maybe<T> Just(const T& t);
+
+#if defined(NODE_ADDON_API_ENABLE_MAYBE)
+template <typename T>
+using MaybeOrValue = Maybe<T>;
+#else
+template <typename T>
+using MaybeOrValue = T;
+#endif
+
+/// Environment for Node-API values and operations.
+///
+/// All Node-API values and operations must be associated with an environment.
+/// An environment instance is always provided to callback functions; that
+/// environment must then be used for any creation of Node-API values or other
+/// Node-API operations within the callback. (Many methods infer the
+/// environment from the `this` instance that the method is called on.)
+///
+/// In the future, multiple environments per process may be supported,
+/// although current implementations only support one environment per process.
+///
+/// In the V8 JavaScript engine, a Node-API environment approximately
+/// corresponds to an Isolate.
+class Env {
+ private:
+  napi_env _env;
+#if NAPI_VERSION > 5
+  template <typename T>
+  static void DefaultFini(Env, T* data);
+  template <typename DataType, typename HintType>
+  static void DefaultFiniWithHint(Env, DataType* data, HintType* hint);
+#endif  // NAPI_VERSION > 5
+ public:
+  Env(napi_env env);
+
+  operator napi_env() const;
+
+  Object Global() const;
+  Value Undefined() const;
+  Value Null() const;
+
+  bool IsExceptionPending() const;
+  Error GetAndClearPendingException() const;
+
+  MaybeOrValue<Value> RunScript(const char* utf8script) const;
+  MaybeOrValue<Value> RunScript(const std::string& utf8script) const;
+  MaybeOrValue<Value> RunScript(String script) const;
+
+#if NAPI_VERSION > 2
+  template <typename Hook, typename Arg = void>
+  class CleanupHook;
+
+  template <typename Hook>
+  CleanupHook<Hook> AddCleanupHook(Hook hook);
+
+  template <typename Hook, typename Arg>
+  CleanupHook<Hook, Arg> AddCleanupHook(Hook hook, Arg* arg);
+#endif  // NAPI_VERSION > 2
+
+#if NAPI_VERSION > 5
+  template <typename T>
+  T* GetInstanceData() const;
+
+  template <typename T>
+  using Finalizer = void (*)(Env, T*);
+  template <typename T, Finalizer<T> fini = Env::DefaultFini<T>>
+  void SetInstanceData(T* data) const;
+
+  template <typename DataType, typename HintType>
+  using FinalizerWithHint = void (*)(Env, DataType*, HintType*);
+  template <typename DataType,
+            typename HintType,
+            FinalizerWithHint<DataType, HintType> fini =
+                Env::DefaultFiniWithHint<DataType, HintType>>
+  void SetInstanceData(DataType* data, HintType* hint) const;
+#endif  // NAPI_VERSION > 5
+
+#if NAPI_VERSION > 2
+  template <typename Hook, typename Arg>
+  class CleanupHook {
+   public:
+    CleanupHook();
+    CleanupHook(Env env, Hook hook, Arg* arg);
+    CleanupHook(Env env, Hook hook);
+    bool Remove(Env env);
+    bool IsEmpty() const;
+
+   private:
+    static inline void Wrapper(void* data) NAPI_NOEXCEPT;
+    static inline void WrapperWithArg(void* data) NAPI_NOEXCEPT;
+
+    void (*wrapper)(void* arg);
+    struct CleanupData {
+      Hook hook;
+      Arg* arg;
+    } * data;
+  };
+#endif  // NAPI_VERSION > 2
+
+#if NAPI_VERSION > 8
+  const char* GetModuleFileName() const;
+#endif  // NAPI_VERSION > 8
+};
+
+/// A JavaScript value of unknown type.
+///
+/// For type-specific operations, convert to one of the Value subclasses using a
+/// `To*` or `As()` method. The `To*` methods do type coercion; the `As()`
+/// method does not.
+///
+///     Napi::Value value = ...
+///     if (!value.IsString()) throw Napi::TypeError::New(env, "Invalid
+///     arg..."); Napi::String str = value.As<Napi::String>(); // Cast to a
+///     string value
+///
+///     Napi::Value anotherValue = ...
+///     bool isTruthy = anotherValue.ToBoolean(); // Coerce to a boolean value
+class Value {
+ public:
+  Value();  ///< Creates a new _empty_ Value instance.
+  Value(napi_env env,
+        napi_value value);  ///< Wraps a Node-API value primitive.
+
+  /// Creates a JS value from a C++ primitive.
+  ///
+  /// `value` may be any of:
+  /// - bool
+  /// - Any integer type
+  /// - Any floating point type
+  /// - const char* (encoded using UTF-8, null-terminated)
+  /// - const char16_t* (encoded using UTF-16-LE, null-terminated)
+  /// - std::string (encoded using UTF-8)
+  /// - std::u16string
+  /// - napi::Value
+  /// - napi_value
+  template <typename T>
+  static Value From(napi_env env, const T& value);
+
+  /// Converts to a Node-API value primitive.
+  ///
+  /// If the instance is _empty_, this returns `nullptr`.
+  operator napi_value() const;
+
+  /// Tests if this value strictly equals another value.
+  bool operator==(const Value& other) const;
+
+  /// Tests if this value does not strictly equal another value.
+  bool operator!=(const Value& other) const;
+
+  /// Tests if this value strictly equals another value.
+  bool StrictEquals(const Value& other) const;
+
+  /// Gets the environment the value is associated with.
+  Napi::Env Env() const;
+
+  /// Checks if the value is empty (uninitialized).
+  ///
+  /// An empty value is invalid, and most attempts to perform an operation on an
+  /// empty value will result in an exception. Note an empty value is distinct
+  /// from JavaScript `null` or `undefined`, which are valid values.
+  ///
+  /// When C++ exceptions are disabled at compile time, a method with a `Value`
+  /// return type may return an empty value to indicate a pending exception. So
+  /// when not using C++ exceptions, callers should check whether the value is
+  /// empty before attempting to use it.
+  bool IsEmpty() const;
+
+  napi_valuetype Type() const;  ///< Gets the type of the value.
+
+  bool IsUndefined()
+      const;            ///< Tests if a value is an undefined JavaScript value.
+  bool IsNull() const;  ///< Tests if a value is a null JavaScript value.
+  bool IsBoolean() const;  ///< Tests if a value is a JavaScript boolean.
+  bool IsNumber() const;   ///< Tests if a value is a JavaScript number.
+#if NAPI_VERSION > 5
+  bool IsBigInt() const;  ///< Tests if a value is a JavaScript bigint.
+#endif                    // NAPI_VERSION > 5
+#if (NAPI_VERSION > 4)
+  bool IsDate() const;  ///< Tests if a value is a JavaScript date.
+#endif
+  bool IsString() const;  ///< Tests if a value is a JavaScript string.
+  bool IsSymbol() const;  ///< Tests if a value is a JavaScript symbol.
+  bool IsArray() const;   ///< Tests if a value is a JavaScript array.
+  bool IsArrayBuffer()
+      const;  ///< Tests if a value is a JavaScript array buffer.
+  bool IsTypedArray() const;  ///< Tests if a value is a JavaScript typed array.
+  bool IsObject() const;      ///< Tests if a value is a JavaScript object.
+  bool IsFunction() const;    ///< Tests if a value is a JavaScript function.
+  bool IsPromise() const;     ///< Tests if a value is a JavaScript promise.
+  bool IsDataView() const;    ///< Tests if a value is a JavaScript data view.
+  bool IsBuffer() const;      ///< Tests if a value is a Node buffer.
+  bool IsExternal() const;  ///< Tests if a value is a pointer to external data.
+
+  /// Casts to another type of `Napi::Value`, when the actual type is known or
+  /// assumed.
+  ///
+  /// This conversion does NOT coerce the type. Calling any methods
+  /// inappropriate for the actual value type will throw `Napi::Error`.
+  ///
+  /// If `NODE_ADDON_API_ENABLE_TYPE_CHECK_ON_AS` is defined, this method
+  /// asserts that the actual type is the expected type.
+  template <typename T>
+  T As() const;
+
+  MaybeOrValue<Boolean> ToBoolean()
+      const;  ///< Coerces a value to a JavaScript boolean.
+  MaybeOrValue<Number> ToNumber()
+      const;  ///< Coerces a value to a JavaScript number.
+  MaybeOrValue<String> ToString()
+      const;  ///< Coerces a value to a JavaScript string.
+  MaybeOrValue<Object> ToObject()
+      const;  ///< Coerces a value to a JavaScript object.
+
+ protected:
+  /// !cond INTERNAL
+  napi_env _env;
+  napi_value _value;
+  /// !endcond
+};
+
+/// A JavaScript boolean value.
+class Boolean : public Value {
+ public:
+  static Boolean New(napi_env env,  ///< Node-API environment
+                     bool value     ///< Boolean value
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Boolean();  ///< Creates a new _empty_ Boolean instance.
+  Boolean(napi_env env,
+          napi_value value);  ///< Wraps a Node-API value primitive.
+
+  operator bool() const;  ///< Converts a Boolean value to a boolean primitive.
+  bool Value() const;     ///< Converts a Boolean value to a boolean primitive.
+};
+
+/// A JavaScript number value.
+class Number : public Value {
+ public:
+  static Number New(napi_env env,  ///< Node-API environment
+                    double value   ///< Number value
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Number();  ///< Creates a new _empty_ Number instance.
+  Number(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+
+  operator int32_t()
+      const;  ///< Converts a Number value to a 32-bit signed integer value.
+  operator uint32_t()
+      const;  ///< Converts a Number value to a 32-bit unsigned integer value.
+  operator int64_t()
+      const;  ///< Converts a Number value to a 64-bit signed integer value.
+  operator float()
+      const;  ///< Converts a Number value to a 32-bit floating-point value.
+  operator double()
+      const;  ///< Converts a Number value to a 64-bit floating-point value.
+
+  int32_t Int32Value()
+      const;  ///< Converts a Number value to a 32-bit signed integer value.
+  uint32_t Uint32Value()
+      const;  ///< Converts a Number value to a 32-bit unsigned integer value.
+  int64_t Int64Value()
+      const;  ///< Converts a Number value to a 64-bit signed integer value.
+  float FloatValue()
+      const;  ///< Converts a Number value to a 32-bit floating-point value.
+  double DoubleValue()
+      const;  ///< Converts a Number value to a 64-bit floating-point value.
+};
+
+#if NAPI_VERSION > 5
+/// A JavaScript bigint value.
+class BigInt : public Value {
+ public:
+  static BigInt New(napi_env env,  ///< Node-API environment
+                    int64_t value  ///< Number value
+  );
+  static BigInt New(napi_env env,   ///< Node-API environment
+                    uint64_t value  ///< Number value
+  );
+
+  /// Creates a new BigInt object using a specified sign bit and a
+  /// specified list of digits/words.
+  /// The resulting number is calculated as:
+  /// (-1)^sign_bit * (words[0] * (2^64)^0 + words[1] * (2^64)^1 + ...)
+  static BigInt New(napi_env env,          ///< Node-API environment
+                    int sign_bit,          ///< Sign bit. 1 if negative.
+                    size_t word_count,     ///< Number of words in array
+                    const uint64_t* words  ///< Array of words
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  BigInt();  ///< Creates a new _empty_ BigInt instance.
+  BigInt(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+
+  int64_t Int64Value(bool* lossless)
+      const;  ///< Converts a BigInt value to a 64-bit signed integer value.
+  uint64_t Uint64Value(bool* lossless)
+      const;  ///< Converts a BigInt value to a 64-bit unsigned integer value.
+
+  size_t WordCount() const;  ///< The number of 64-bit words needed to store
+                             ///< the result of ToWords().
+
+  /// Writes the contents of this BigInt to a specified memory location.
+  /// `sign_bit` must be provided and will be set to 1 if this BigInt is
+  /// negative.
+  /// `*word_count` has to be initialized to the length of the `words` array.
+  /// Upon return, it will be set to the actual number of words that would
+  /// be needed to store this BigInt (i.e. the return value of `WordCount()`).
+  void ToWords(int* sign_bit, size_t* word_count, uint64_t* words);
+};
+#endif  // NAPI_VERSION > 5
+
+#if (NAPI_VERSION > 4)
+/// A JavaScript date value.
+class Date : public Value {
+ public:
+  /// Creates a new Date value from a double primitive.
+  static Date New(napi_env env,  ///< Node-API environment
+                  double value   ///< Number value
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Date();  ///< Creates a new _empty_ Date instance.
+  Date(napi_env env, napi_value value);  ///< Wraps a Node-API value primitive.
+  operator double() const;  ///< Converts a Date value to double primitive
+
+  double ValueOf() const;  ///< Converts a Date value to a double primitive.
+};
+#endif
+
+/// A JavaScript string or symbol value (that can be used as a property name).
+class Name : public Value {
+ public:
+  static void CheckCast(napi_env env, napi_value value);
+
+  Name();  ///< Creates a new _empty_ Name instance.
+  Name(napi_env env,
+       napi_value value);  ///< Wraps a Node-API value primitive.
+};
+
+/// A JavaScript string value.
+class String : public Name {
+ public:
+  /// Creates a new String value from a UTF-8 encoded C++ string.
+  static String New(napi_env env,             ///< Node-API environment
+                    const std::string& value  ///< UTF-8 encoded C++ string
+  );
+
+  /// Creates a new String value from a UTF-16 encoded C++ string.
+  static String New(napi_env env,                ///< Node-API environment
+                    const std::u16string& value  ///< UTF-16 encoded C++ string
+  );
+
+  /// Creates a new String value from a UTF-8 encoded C string.
+  static String New(
+      napi_env env,      ///< Node-API environment
+      const char* value  ///< UTF-8 encoded null-terminated C string
+  );
+
+  /// Creates a new String value from a UTF-16 encoded C string.
+  static String New(
+      napi_env env,          ///< Node-API environment
+      const char16_t* value  ///< UTF-16 encoded null-terminated C string
+  );
+
+  /// Creates a new String value from a UTF-8 encoded C string with specified
+  /// length.
+  static String New(napi_env env,       ///< Node-API environment
+                    const char* value,  ///< UTF-8 encoded C string (not
+                                        ///< necessarily null-terminated)
+                    size_t length       ///< length of the string in bytes
+  );
+
+  /// Creates a new String value from a UTF-16 encoded C string with specified
+  /// length.
+  static String New(
+      napi_env env,           ///< Node-API environment
+      const char16_t* value,  ///< UTF-16 encoded C string (not necessarily
+                              ///< null-terminated)
+      size_t length           ///< Length of the string in 2-byte code units
+  );
+
+  /// Creates a new String based on the original object's type.
+  ///
+  /// `value` may be any of:
+  /// - const char* (encoded using UTF-8, null-terminated)
+  /// - const char16_t* (encoded using UTF-16-LE, null-terminated)
+  /// - std::string (encoded using UTF-8)
+  /// - std::u16string
+  template <typename T>
+  static String From(napi_env env, const T& value);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  String();  ///< Creates a new _empty_ String instance.
+  String(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+
+  operator std::string()
+      const;  ///< Converts a String value to a UTF-8 encoded C++ string.
+  operator std::u16string()
+      const;  ///< Converts a String value to a UTF-16 encoded C++ string.
+  std::string Utf8Value()
+      const;  ///< Converts a String value to a UTF-8 encoded C++ string.
+  std::u16string Utf16Value()
+      const;  ///< Converts a String value to a UTF-16 encoded C++ string.
+};
+
+/// A JavaScript symbol value.
+class Symbol : public Name {
+ public:
+  /// Creates a new Symbol value with an optional description.
+  static Symbol New(
+      napi_env env,  ///< Node-API environment
+      const char* description =
+          nullptr  ///< Optional UTF-8 encoded null-terminated C string
+                   ///  describing the symbol
+  );
+
+  /// Creates a new Symbol value with a description.
+  static Symbol New(
+      napi_env env,  ///< Node-API environment
+      const std::string&
+          description  ///< UTF-8 encoded C++ string describing the symbol
+  );
+
+  /// Creates a new Symbol value with a description.
+  static Symbol New(napi_env env,       ///< Node-API environment
+                    String description  ///< String value describing the symbol
+  );
+
+  /// Creates a new Symbol value with a description.
+  static Symbol New(
+      napi_env env,           ///< Node-API environment
+      napi_value description  ///< String value describing the symbol
+  );
+
+  /// Get a public Symbol (e.g. Symbol.iterator).
+  static MaybeOrValue<Symbol> WellKnown(napi_env, const std::string& name);
+
+  // Create a symbol in the global registry, UTF-8 Encoded cpp string
+  static MaybeOrValue<Symbol> For(napi_env env, const std::string& description);
+
+  // Create a symbol in the global registry, C style string (null terminated)
+  static MaybeOrValue<Symbol> For(napi_env env, const char* description);
+
+  // Create a symbol in the global registry, String value describing the symbol
+  static MaybeOrValue<Symbol> For(napi_env env, String description);
+
+  // Create a symbol in the global registry, napi_value describing the symbol
+  static MaybeOrValue<Symbol> For(napi_env env, napi_value description);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Symbol();  ///< Creates a new _empty_ Symbol instance.
+  Symbol(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+};
+
+class TypeTaggable : public Value {
+ public:
+#if NAPI_VERSION >= 8
+  void TypeTag(const napi_type_tag* type_tag) const;
+  bool CheckTypeTag(const napi_type_tag* type_tag) const;
+#endif  // NAPI_VERSION >= 8
+ protected:
+  TypeTaggable();
+  TypeTaggable(napi_env env, napi_value value);
+};
+
+/// A JavaScript object value.
+class Object : public TypeTaggable {
+ public:
+  /// Enables property and element assignments using indexing syntax.
+  ///
+  /// This is a convenient helper to get and set object properties. As
+  /// getting and setting object properties may throw with JavaScript
+  /// exceptions, it is notable that these operations may fail.
+  /// When NODE_ADDON_API_ENABLE_MAYBE is defined, the process will abort
+  /// on JavaScript exceptions.
+  ///
+  /// Example:
+  ///
+  ///     Napi::Value propertyValue = object1['A'];
+  ///     object2['A'] = propertyValue;
+  ///     Napi::Value elementValue = array[0];
+  ///     array[1] = elementValue;
+  template <typename Key>
+  class PropertyLValue {
+   public:
+    /// Converts an L-value to a value.
+    operator Value() const;
+
+    /// Assigns a value to the property. The type of value can be
+    /// anything supported by `Object::Set`.
+    template <typename ValueType>
+    PropertyLValue& operator=(ValueType value);
+
+   private:
+    PropertyLValue() = delete;
+    PropertyLValue(Object object, Key key);
+    napi_env _env;
+    napi_value _object;
+    Key _key;
+
+    friend class Napi::Object;
+  };
+
+  /// Creates a new Object value.
+  static Object New(napi_env env  ///< Node-API environment
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Object();  ///< Creates a new _empty_ Object instance.
+  Object(napi_env env,
+         napi_value value);  ///< Wraps a Node-API value primitive.
+
+  /// Gets or sets a named property.
+  PropertyLValue<std::string> operator[](
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  );
+
+  /// Gets or sets a named property.
+  PropertyLValue<std::string> operator[](
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  );
+
+  /// Gets or sets an indexed property or array element.
+  PropertyLValue<uint32_t> operator[](
+      uint32_t index  /// Property / element index
+  );
+
+  /// Gets or sets an indexed property or array element.
+  PropertyLValue<Value> operator[](Value index  /// Property / element index
+  ) const;
+
+  /// Gets a named property.
+  MaybeOrValue<Value> operator[](
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Gets a named property.
+  MaybeOrValue<Value> operator[](
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Gets an indexed property or array element.
+  MaybeOrValue<Value> operator[](uint32_t index  ///< Property / element index
+  ) const;
+
+  /// Checks whether a property is present.
+  MaybeOrValue<bool> Has(napi_value key  ///< Property key primitive
+  ) const;
+
+  /// Checks whether a property is present.
+  MaybeOrValue<bool> Has(Value key  ///< Property key
+  ) const;
+
+  /// Checks whether a named property is present.
+  MaybeOrValue<bool> Has(
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Checks whether a named property is present.
+  MaybeOrValue<bool> Has(
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Checks whether a own property is present.
+  MaybeOrValue<bool> HasOwnProperty(napi_value key  ///< Property key primitive
+  ) const;
+
+  /// Checks whether a own property is present.
+  MaybeOrValue<bool> HasOwnProperty(Value key  ///< Property key
+  ) const;
+
+  /// Checks whether a own property is present.
+  MaybeOrValue<bool> HasOwnProperty(
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Checks whether a own property is present.
+  MaybeOrValue<bool> HasOwnProperty(
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Gets a property.
+  MaybeOrValue<Value> Get(napi_value key  ///< Property key primitive
+  ) const;
+
+  /// Gets a property.
+  MaybeOrValue<Value> Get(Value key  ///< Property key
+  ) const;
+
+  /// Gets a named property.
+  MaybeOrValue<Value> Get(
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Gets a named property.
+  MaybeOrValue<Value> Get(
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Sets a property.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(napi_value key,         ///< Property key primitive
+                         const ValueType& value  ///< Property value primitive
+  ) const;
+
+  /// Sets a property.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(Value key,              ///< Property key
+                         const ValueType& value  ///< Property value
+  ) const;
+
+  /// Sets a named property.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(
+      const char* utf8name,  ///< UTF-8 encoded null-terminated property name
+      const ValueType& value) const;
+
+  /// Sets a named property.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(
+      const std::string& utf8name,  ///< UTF-8 encoded property name
+      const ValueType& value        ///< Property value primitive
+  ) const;
+
+  /// Delete property.
+  MaybeOrValue<bool> Delete(napi_value key  ///< Property key primitive
+  ) const;
+
+  /// Delete property.
+  MaybeOrValue<bool> Delete(Value key  ///< Property key
+  ) const;
+
+  /// Delete property.
+  MaybeOrValue<bool> Delete(
+      const char* utf8name  ///< UTF-8 encoded null-terminated property name
+  ) const;
+
+  /// Delete property.
+  MaybeOrValue<bool> Delete(
+      const std::string& utf8name  ///< UTF-8 encoded property name
+  ) const;
+
+  /// Checks whether an indexed property is present.
+  MaybeOrValue<bool> Has(uint32_t index  ///< Property / element index
+  ) const;
+
+  /// Gets an indexed property or array element.
+  MaybeOrValue<Value> Get(uint32_t index  ///< Property / element index
+  ) const;
+
+  /// Sets an indexed property or array element.
+  template <typename ValueType>
+  MaybeOrValue<bool> Set(uint32_t index,         ///< Property / element index
+                         const ValueType& value  ///< Property value primitive
+  ) const;
+
+  /// Deletes an indexed property or array element.
+  MaybeOrValue<bool> Delete(uint32_t index  ///< Property / element index
+  ) const;
+
+  /// This operation can fail in case of Proxy.[[OwnPropertyKeys]] and
+  /// Proxy.[[GetOwnProperty]] calling into JavaScript. See:
+  /// -
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys
+  /// -
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getownproperty-p
+  MaybeOrValue<Array> GetPropertyNames() const;  ///< Get all property names
+
+  /// Defines a property on the object.
+  ///
+  /// This operation can fail in case of Proxy.[[DefineOwnProperty]] calling
+  /// into JavaScript. See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc
+  MaybeOrValue<bool> DefineProperty(
+      const PropertyDescriptor&
+          property  ///< Descriptor for the property to be defined
+  ) const;
+
+  /// Defines properties on the object.
+  ///
+  /// This operation can fail in case of Proxy.[[DefineOwnProperty]] calling
+  /// into JavaScript. See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc
+  MaybeOrValue<bool> DefineProperties(
+      const std::initializer_list<PropertyDescriptor>& properties
+      ///< List of descriptors for the properties to be defined
+  ) const;
+
+  /// Defines properties on the object.
+  ///
+  /// This operation can fail in case of Proxy.[[DefineOwnProperty]] calling
+  /// into JavaScript. See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc
+  MaybeOrValue<bool> DefineProperties(
+      const std::vector<PropertyDescriptor>& properties
+      ///< Vector of descriptors for the properties to be defined
+  ) const;
+
+  /// Checks if an object is an instance created by a constructor function.
+  ///
+  /// This is equivalent to the JavaScript `instanceof` operator.
+  ///
+  /// This operation can fail in case of Proxy.[[GetPrototypeOf]] calling into
+  /// JavaScript.
+  /// See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof
+  MaybeOrValue<bool> InstanceOf(
+      const Function& constructor  ///< Constructor function
+  ) const;
+
+  template <typename Finalizer, typename T>
+  inline void AddFinalizer(Finalizer finalizeCallback, T* data) const;
+
+  template <typename Finalizer, typename T, typename Hint>
+  inline void AddFinalizer(Finalizer finalizeCallback,
+                           T* data,
+                           Hint* finalizeHint) const;
+
+#ifdef NAPI_CPP_EXCEPTIONS
+  class const_iterator;
+
+  inline const_iterator begin() const;
+
+  inline const_iterator end() const;
+
+  class iterator;
+
+  inline iterator begin();
+
+  inline iterator end();
+#endif  // NAPI_CPP_EXCEPTIONS
+
+#if NAPI_VERSION >= 8
+  /// This operation can fail in case of Proxy.[[GetPrototypeOf]] calling into
+  /// JavaScript.
+  /// See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof
+  MaybeOrValue<bool> Freeze() const;
+  /// This operation can fail in case of Proxy.[[GetPrototypeOf]] calling into
+  /// JavaScript.
+  /// See
+  /// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof
+  MaybeOrValue<bool> Seal() const;
+#endif  // NAPI_VERSION >= 8
+};
+
+template <typename T>
+class External : public TypeTaggable {
+ public:
+  static External New(napi_env env, T* data);
+
+  // Finalizer must implement `void operator()(Env env, T* data)`.
+  template <typename Finalizer>
+  static External New(napi_env env, T* data, Finalizer finalizeCallback);
+  // Finalizer must implement `void operator()(Env env, T* data, Hint* hint)`.
+  template <typename Finalizer, typename Hint>
+  static External New(napi_env env,
+                      T* data,
+                      Finalizer finalizeCallback,
+                      Hint* finalizeHint);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  External();
+  External(napi_env env, napi_value value);
+
+  T* Data() const;
+};
+
+class Array : public Object {
+ public:
+  static Array New(napi_env env);
+  static Array New(napi_env env, size_t length);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Array();
+  Array(napi_env env, napi_value value);
+
+  uint32_t Length() const;
+};
+
+#ifdef NAPI_CPP_EXCEPTIONS
+class Object::const_iterator {
+ private:
+  enum class Type { BEGIN, END };
+
+  inline const_iterator(const Object* object, const Type type);
+
+ public:
+  inline const_iterator& operator++();
+
+  inline bool operator==(const const_iterator& other) const;
+
+  inline bool operator!=(const const_iterator& other) const;
+
+  inline const std::pair<Value, Object::PropertyLValue<Value>> operator*()
+      const;
+
+ private:
+  const Napi::Object* _object;
+  Array _keys;
+  uint32_t _index;
+
+  friend class Object;
+};
+
+class Object::iterator {
+ private:
+  enum class Type { BEGIN, END };
+
+  inline iterator(Object* object, const Type type);
+
+ public:
+  inline iterator& operator++();
+
+  inline bool operator==(const iterator& other) const;
+
+  inline bool operator!=(const iterator& other) const;
+
+  inline std::pair<Value, Object::PropertyLValue<Value>> operator*();
+
+ private:
+  Napi::Object* _object;
+  Array _keys;
+  uint32_t _index;
+
+  friend class Object;
+};
+#endif  // NAPI_CPP_EXCEPTIONS
+
+/// A JavaScript array buffer value.
+class ArrayBuffer : public Object {
+ public:
+  /// Creates a new ArrayBuffer instance over a new automatically-allocated
+  /// buffer.
+  static ArrayBuffer New(
+      napi_env env,      ///< Node-API environment
+      size_t byteLength  ///< Length of the buffer to be allocated, in bytes
+  );
+
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  /// Creates a new ArrayBuffer instance, using an external buffer with
+  /// specified byte length.
+  static ArrayBuffer New(
+      napi_env env,        ///< Node-API environment
+      void* externalData,  ///< Pointer to the external buffer to be used by
+                           ///< the array
+      size_t byteLength    ///< Length of the external buffer to be used by the
+                           ///< array, in bytes
+  );
+
+  /// Creates a new ArrayBuffer instance, using an external buffer with
+  /// specified byte length.
+  template <typename Finalizer>
+  static ArrayBuffer New(
+      napi_env env,        ///< Node-API environment
+      void* externalData,  ///< Pointer to the external buffer to be used by
+                           ///< the array
+      size_t byteLength,   ///< Length of the external buffer to be used by the
+                           ///< array,
+                           ///  in bytes
+      Finalizer finalizeCallback  ///< Function to be called when the array
+                                  ///< buffer is destroyed;
+                                  ///  must implement `void operator()(Env env,
+                                  ///  void* externalData)`
+  );
+
+  /// Creates a new ArrayBuffer instance, using an external buffer with
+  /// specified byte length.
+  template <typename Finalizer, typename Hint>
+  static ArrayBuffer New(
+      napi_env env,        ///< Node-API environment
+      void* externalData,  ///< Pointer to the external buffer to be used by
+                           ///< the array
+      size_t byteLength,   ///< Length of the external buffer to be used by the
+                           ///< array,
+                           ///  in bytes
+      Finalizer finalizeCallback,  ///< Function to be called when the array
+                                   ///< buffer is destroyed;
+                                   ///  must implement `void operator()(Env
+                                   ///  env, void* externalData, Hint* hint)`
+      Hint* finalizeHint  ///< Hint (second parameter) to be passed to the
+                          ///< finalize callback
+  );
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  ArrayBuffer();  ///< Creates a new _empty_ ArrayBuffer instance.
+  ArrayBuffer(napi_env env,
+              napi_value value);  ///< Wraps a Node-API value primitive.
+
+  void* Data();         ///< Gets a pointer to the data buffer.
+  size_t ByteLength();  ///< Gets the length of the array buffer in bytes.
+
+#if NAPI_VERSION >= 7
+  bool IsDetached() const;
+  void Detach();
+#endif  // NAPI_VERSION >= 7
+};
+
+/// A JavaScript typed-array value with unknown array type.
+///
+/// For type-specific operations, cast to a `TypedArrayOf<T>` instance using the
+/// `As()` method:
+///
+///     Napi::TypedArray array = ...
+///     if (t.TypedArrayType() == napi_int32_array) {
+///         Napi::Int32Array int32Array = t.As<Napi::Int32Array>();
+///     }
+class TypedArray : public Object {
+ public:
+  static void CheckCast(napi_env env, napi_value value);
+
+  TypedArray();  ///< Creates a new _empty_ TypedArray instance.
+  TypedArray(napi_env env,
+             napi_value value);  ///< Wraps a Node-API value primitive.
+
+  napi_typedarray_type TypedArrayType()
+      const;  ///< Gets the type of this typed-array.
+  Napi::ArrayBuffer ArrayBuffer() const;  ///< Gets the backing array buffer.
+
+  uint8_t ElementSize()
+      const;  ///< Gets the size in bytes of one element in the array.
+  size_t ElementLength() const;  ///< Gets the number of elements in the array.
+  size_t ByteOffset()
+      const;  ///< Gets the offset into the buffer where the array starts.
+  size_t ByteLength() const;  ///< Gets the length of the array in bytes.
+
+ protected:
+  /// !cond INTERNAL
+  napi_typedarray_type _type;
+  size_t _length;
+
+  TypedArray(napi_env env,
+             napi_value value,
+             napi_typedarray_type type,
+             size_t length);
+
+  template <typename T>
+  static
+#if defined(NAPI_HAS_CONSTEXPR)
+      constexpr
+#endif
+      napi_typedarray_type
+      TypedArrayTypeForPrimitiveType() {
+    return std::is_same<T, int8_t>::value     ? napi_int8_array
+           : std::is_same<T, uint8_t>::value  ? napi_uint8_array
+           : std::is_same<T, int16_t>::value  ? napi_int16_array
+           : std::is_same<T, uint16_t>::value ? napi_uint16_array
+           : std::is_same<T, int32_t>::value  ? napi_int32_array
+           : std::is_same<T, uint32_t>::value ? napi_uint32_array
+           : std::is_same<T, float>::value    ? napi_float32_array
+           : std::is_same<T, double>::value   ? napi_float64_array
+#if NAPI_VERSION > 5
+           : std::is_same<T, int64_t>::value  ? napi_bigint64_array
+           : std::is_same<T, uint64_t>::value ? napi_biguint64_array
+#endif  // NAPI_VERSION > 5
+                                              : napi_int8_array;
+  }
+  /// !endcond
+};
+
+/// A JavaScript typed-array value with known array type.
+///
+/// Note while it is possible to create and access Uint8 "clamped" arrays using
+/// this class, the _clamping_ behavior is only applied in JavaScript.
+template <typename T>
+class TypedArrayOf : public TypedArray {
+ public:
+  /// Creates a new TypedArray instance over a new automatically-allocated array
+  /// buffer.
+  ///
+  /// The array type parameter can normally be omitted (because it is inferred
+  /// from the template parameter T), except when creating a "clamped" array:
+  ///
+  ///     Uint8Array::New(env, length, napi_uint8_clamped_array)
+  static TypedArrayOf New(
+      napi_env env,          ///< Node-API environment
+      size_t elementLength,  ///< Length of the created array, as a number of
+                             ///< elements
+#if defined(NAPI_HAS_CONSTEXPR)
+      napi_typedarray_type type =
+          TypedArray::TypedArrayTypeForPrimitiveType<T>()
+#else
+        napi_typedarray_type type
+#endif
+      ///< Type of array, if different from the default array type for the
+      ///< template parameter T.
+  );
+
+  /// Creates a new TypedArray instance over a provided array buffer.
+  ///
+  /// The array type parameter can normally be omitted (because it is inferred
+  /// from the template parameter T), except when creating a "clamped" array:
+  ///
+  ///     Uint8Array::New(env, length, buffer, 0, napi_uint8_clamped_array)
+  static TypedArrayOf New(
+      napi_env env,          ///< Node-API environment
+      size_t elementLength,  ///< Length of the created array, as a number of
+                             ///< elements
+      Napi::ArrayBuffer arrayBuffer,  ///< Backing array buffer instance to use
+      size_t bufferOffset,  ///< Offset into the array buffer where the
+                            ///< typed-array starts
+#if defined(NAPI_HAS_CONSTEXPR)
+      napi_typedarray_type type =
+          TypedArray::TypedArrayTypeForPrimitiveType<T>()
+#else
+        napi_typedarray_type type
+#endif
+      ///< Type of array, if different from the default array type for the
+      ///< template parameter T.
+  );
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  TypedArrayOf();  ///< Creates a new _empty_ TypedArrayOf instance.
+  TypedArrayOf(napi_env env,
+               napi_value value);  ///< Wraps a Node-API value primitive.
+
+  T& operator[](size_t index);  ///< Gets or sets an element in the array.
+  const T& operator[](size_t index) const;  ///< Gets an element in the array.
+
+  /// Gets a pointer to the array's backing buffer.
+  ///
+  /// This is not necessarily the same as the `ArrayBuffer::Data()` pointer,
+  /// because the typed-array may have a non-zero `ByteOffset()` into the
+  /// `ArrayBuffer`.
+  T* Data();
+
+  /// Gets a pointer to the array's backing buffer.
+  ///
+  /// This is not necessarily the same as the `ArrayBuffer::Data()` pointer,
+  /// because the typed-array may have a non-zero `ByteOffset()` into the
+  /// `ArrayBuffer`.
+  const T* Data() const;
+
+ private:
+  T* _data;
+
+  TypedArrayOf(napi_env env,
+               napi_value value,
+               napi_typedarray_type type,
+               size_t length,
+               T* data);
+};
+
+/// The DataView provides a low-level interface for reading/writing multiple
+/// number types in an ArrayBuffer irrespective of the platform's endianness.
+class DataView : public Object {
+ public:
+  static DataView New(napi_env env, Napi::ArrayBuffer arrayBuffer);
+  static DataView New(napi_env env,
+                      Napi::ArrayBuffer arrayBuffer,
+                      size_t byteOffset);
+  static DataView New(napi_env env,
+                      Napi::ArrayBuffer arrayBuffer,
+                      size_t byteOffset,
+                      size_t byteLength);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  DataView();  ///< Creates a new _empty_ DataView instance.
+  DataView(napi_env env,
+           napi_value value);  ///< Wraps a Node-API value primitive.
+
+  Napi::ArrayBuffer ArrayBuffer() const;  ///< Gets the backing array buffer.
+  size_t ByteOffset()
+      const;  ///< Gets the offset into the buffer where the array starts.
+  size_t ByteLength() const;  ///< Gets the length of the array in bytes.
+
+  void* Data() const;
+
+  float GetFloat32(size_t byteOffset) const;
+  double GetFloat64(size_t byteOffset) const;
+  int8_t GetInt8(size_t byteOffset) const;
+  int16_t GetInt16(size_t byteOffset) const;
+  int32_t GetInt32(size_t byteOffset) const;
+  uint8_t GetUint8(size_t byteOffset) const;
+  uint16_t GetUint16(size_t byteOffset) const;
+  uint32_t GetUint32(size_t byteOffset) const;
+
+  void SetFloat32(size_t byteOffset, float value) const;
+  void SetFloat64(size_t byteOffset, double value) const;
+  void SetInt8(size_t byteOffset, int8_t value) const;
+  void SetInt16(size_t byteOffset, int16_t value) const;
+  void SetInt32(size_t byteOffset, int32_t value) const;
+  void SetUint8(size_t byteOffset, uint8_t value) const;
+  void SetUint16(size_t byteOffset, uint16_t value) const;
+  void SetUint32(size_t byteOffset, uint32_t value) const;
+
+ private:
+  template <typename T>
+  T ReadData(size_t byteOffset) const;
+
+  template <typename T>
+  void WriteData(size_t byteOffset, T value) const;
+
+  void* _data;
+  size_t _length;
+};
+
+class Function : public Object {
+ public:
+  using VoidCallback = void (*)(const CallbackInfo& info);
+  using Callback = Value (*)(const CallbackInfo& info);
+
+  template <VoidCallback cb>
+  static Function New(napi_env env,
+                      const char* utf8name = nullptr,
+                      void* data = nullptr);
+
+  template <Callback cb>
+  static Function New(napi_env env,
+                      const char* utf8name = nullptr,
+                      void* data = nullptr);
+
+  template <VoidCallback cb>
+  static Function New(napi_env env,
+                      const std::string& utf8name,
+                      void* data = nullptr);
+
+  template <Callback cb>
+  static Function New(napi_env env,
+                      const std::string& utf8name,
+                      void* data = nullptr);
+
+  /// Callable must implement operator() accepting a const CallbackInfo&
+  /// and return either void or Value.
+  template <typename Callable>
+  static Function New(napi_env env,
+                      Callable cb,
+                      const char* utf8name = nullptr,
+                      void* data = nullptr);
+  /// Callable must implement operator() accepting a const CallbackInfo&
+  /// and return either void or Value.
+  template <typename Callable>
+  static Function New(napi_env env,
+                      Callable cb,
+                      const std::string& utf8name,
+                      void* data = nullptr);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Function();
+  Function(napi_env env, napi_value value);
+
+  MaybeOrValue<Value> operator()(
+      const std::initializer_list<napi_value>& args) const;
+
+  MaybeOrValue<Value> Call(const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Value> Call(const std::vector<napi_value>& args) const;
+  MaybeOrValue<Value> Call(const std::vector<Value>& args) const;
+  MaybeOrValue<Value> Call(size_t argc, const napi_value* args) const;
+  MaybeOrValue<Value> Call(napi_value recv,
+                           const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Value> Call(napi_value recv,
+                           const std::vector<napi_value>& args) const;
+  MaybeOrValue<Value> Call(napi_value recv,
+                           const std::vector<Value>& args) const;
+  MaybeOrValue<Value> Call(napi_value recv,
+                           size_t argc,
+                           const napi_value* args) const;
+
+  MaybeOrValue<Value> MakeCallback(
+      napi_value recv,
+      const std::initializer_list<napi_value>& args,
+      napi_async_context context = nullptr) const;
+  MaybeOrValue<Value> MakeCallback(napi_value recv,
+                                   const std::vector<napi_value>& args,
+                                   napi_async_context context = nullptr) const;
+  MaybeOrValue<Value> MakeCallback(napi_value recv,
+                                   size_t argc,
+                                   const napi_value* args,
+                                   napi_async_context context = nullptr) const;
+
+  MaybeOrValue<Object> New(const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Object> New(const std::vector<napi_value>& args) const;
+  MaybeOrValue<Object> New(size_t argc, const napi_value* args) const;
+};
+
+class Promise : public Object {
+ public:
+  class Deferred {
+   public:
+    static Deferred New(napi_env env);
+    Deferred(napi_env env);
+
+    Napi::Promise Promise() const;
+    Napi::Env Env() const;
+
+    void Resolve(napi_value value) const;
+    void Reject(napi_value value) const;
+
+   private:
+    napi_env _env;
+    napi_deferred _deferred;
+    napi_value _promise;
+  };
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Promise(napi_env env, napi_value value);
+};
+
+template <typename T>
+class Buffer : public Uint8Array {
+ public:
+  static Buffer<T> New(napi_env env, size_t length);
+#ifndef NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+  static Buffer<T> New(napi_env env, T* data, size_t length);
+
+  // Finalizer must implement `void operator()(Env env, T* data)`.
+  template <typename Finalizer>
+  static Buffer<T> New(napi_env env,
+                       T* data,
+                       size_t length,
+                       Finalizer finalizeCallback);
+  // Finalizer must implement `void operator()(Env env, T* data, Hint* hint)`.
+  template <typename Finalizer, typename Hint>
+  static Buffer<T> New(napi_env env,
+                       T* data,
+                       size_t length,
+                       Finalizer finalizeCallback,
+                       Hint* finalizeHint);
+#endif  // NODE_API_NO_EXTERNAL_BUFFERS_ALLOWED
+
+  static Buffer<T> NewOrCopy(napi_env env, T* data, size_t length);
+  // Finalizer must implement `void operator()(Env env, T* data)`.
+  template <typename Finalizer>
+  static Buffer<T> NewOrCopy(napi_env env,
+                             T* data,
+                             size_t length,
+                             Finalizer finalizeCallback);
+  // Finalizer must implement `void operator()(Env env, T* data, Hint* hint)`.
+  template <typename Finalizer, typename Hint>
+  static Buffer<T> NewOrCopy(napi_env env,
+                             T* data,
+                             size_t length,
+                             Finalizer finalizeCallback,
+                             Hint* finalizeHint);
+
+  static Buffer<T> Copy(napi_env env, const T* data, size_t length);
+
+  static void CheckCast(napi_env env, napi_value value);
+
+  Buffer();
+  Buffer(napi_env env, napi_value value);
+  size_t Length() const;
+  T* Data() const;
+
+ private:
+};
+
+/// Holds a counted reference to a value; initially a weak reference unless
+/// otherwise specified, may be changed to/from a strong reference by adjusting
+/// the refcount.
+///
+/// The referenced value is not immediately destroyed when the reference count
+/// is zero; it is merely then eligible for garbage-collection if there are no
+/// other references to the value.
+template <typename T>
+class Reference {
+ public:
+  static Reference<T> New(const T& value, uint32_t initialRefcount = 0);
+
+  Reference();
+  Reference(napi_env env, napi_ref ref);
+  ~Reference();
+
+  // A reference can be moved but cannot be copied.
+  Reference(Reference<T>&& other);
+  Reference<T>& operator=(Reference<T>&& other);
+  NAPI_DISALLOW_ASSIGN(Reference<T>)
+
+  operator napi_ref() const;
+  bool operator==(const Reference<T>& other) const;
+  bool operator!=(const Reference<T>& other) const;
+
+  Napi::Env Env() const;
+  bool IsEmpty() const;
+
+  // Note when getting the value of a Reference it is usually correct to do so
+  // within a HandleScope so that the value handle gets cleaned up efficiently.
+  T Value() const;
+
+  uint32_t Ref() const;
+  uint32_t Unref() const;
+  void Reset();
+  void Reset(const T& value, uint32_t refcount = 0);
+
+  // Call this on a reference that is declared as static data, to prevent its
+  // destructor from running at program shutdown time, which would attempt to
+  // reset the reference when the environment is no longer valid. Avoid using
+  // this if at all possible. If you do need to use static data, MAKE SURE to
+  // warn your users that your addon is NOT threadsafe.
+  void SuppressDestruct();
+
+ protected:
+  Reference(const Reference<T>&);
+
+  /// !cond INTERNAL
+  napi_env _env;
+  napi_ref _ref;
+  /// !endcond
+
+ private:
+  bool _suppressDestruct;
+};
+
+class ObjectReference : public Reference<Object> {
+ public:
+  ObjectReference();
+  ObjectReference(napi_env env, napi_ref ref);
+
+  // A reference can be moved but cannot be copied.
+  ObjectReference(Reference<Object>&& other);
+  ObjectReference& operator=(Reference<Object>&& other);
+  ObjectReference(ObjectReference&& other);
+  ObjectReference& operator=(ObjectReference&& other);
+  NAPI_DISALLOW_ASSIGN(ObjectReference)
+
+  MaybeOrValue<Napi::Value> Get(const char* utf8name) const;
+  MaybeOrValue<Napi::Value> Get(const std::string& utf8name) const;
+  MaybeOrValue<bool> Set(const char* utf8name, napi_value value) const;
+  MaybeOrValue<bool> Set(const char* utf8name, Napi::Value value) const;
+  MaybeOrValue<bool> Set(const char* utf8name, const char* utf8value) const;
+  MaybeOrValue<bool> Set(const char* utf8name, bool boolValue) const;
+  MaybeOrValue<bool> Set(const char* utf8name, double numberValue) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name, napi_value value) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name, Napi::Value value) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name,
+                         std::string& utf8value) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name, bool boolValue) const;
+  MaybeOrValue<bool> Set(const std::string& utf8name, double numberValue) const;
+
+  MaybeOrValue<Napi::Value> Get(uint32_t index) const;
+  MaybeOrValue<bool> Set(uint32_t index, const napi_value value) const;
+  MaybeOrValue<bool> Set(uint32_t index, const Napi::Value value) const;
+  MaybeOrValue<bool> Set(uint32_t index, const char* utf8value) const;
+  MaybeOrValue<bool> Set(uint32_t index, const std::string& utf8value) const;
+  MaybeOrValue<bool> Set(uint32_t index, bool boolValue) const;
+  MaybeOrValue<bool> Set(uint32_t index, double numberValue) const;
+
+ protected:
+  ObjectReference(const ObjectReference&);
+};
+
+class FunctionReference : public Reference<Function> {
+ public:
+  FunctionReference();
+  FunctionReference(napi_env env, napi_ref ref);
+
+  // A reference can be moved but cannot be copied.
+  FunctionReference(Reference<Function>&& other);
+  FunctionReference& operator=(Reference<Function>&& other);
+  FunctionReference(FunctionReference&& other);
+  FunctionReference& operator=(FunctionReference&& other);
+  NAPI_DISALLOW_ASSIGN_COPY(FunctionReference)
+
+  MaybeOrValue<Napi::Value> operator()(
+      const std::initializer_list<napi_value>& args) const;
+
+  MaybeOrValue<Napi::Value> Call(
+      const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Napi::Value> Call(const std::vector<napi_value>& args) const;
+  MaybeOrValue<Napi::Value> Call(
+      napi_value recv, const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Napi::Value> Call(napi_value recv,
+                                 const std::vector<napi_value>& args) const;
+  MaybeOrValue<Napi::Value> Call(napi_value recv,
+                                 size_t argc,
+                                 const napi_value* args) const;
+
+  MaybeOrValue<Napi::Value> MakeCallback(
+      napi_value recv,
+      const std::initializer_list<napi_value>& args,
+      napi_async_context context = nullptr) const;
+  MaybeOrValue<Napi::Value> MakeCallback(
+      napi_value recv,
+      const std::vector<napi_value>& args,
+      napi_async_context context = nullptr) const;
+  MaybeOrValue<Napi::Value> MakeCallback(
+      napi_value recv,
+      size_t argc,
+      const napi_value* args,
+      napi_async_context context = nullptr) const;
+
+  MaybeOrValue<Object> New(const std::initializer_list<napi_value>& args) const;
+  MaybeOrValue<Object> New(const std::vector<napi_value>& args) const;
+};
+
+// Shortcuts to creating a new reference with inferred type and refcount = 0.
+template <typename T>
+Reference<T> Weak(T value);
+ObjectReference Weak(Object value);
+FunctionReference Weak(Function value);
+
+// Shortcuts to creating a new reference with inferred type and refcount = 1.
+template <typename T>
+Reference<T> Persistent(T value);
+ObjectReference Persistent(Object value);
+FunctionReference Persistent(Function value);
+
+/// A persistent reference to a JavaScript error object. Use of this class
+/// depends somewhat on whether C++ exceptions are enabled at compile time.
+///
+/// ### Handling Errors With C++ Exceptions
+///
+/// If C++ exceptions are enabled, then the `Error` class extends
+/// `std::exception` and enables integrated error-handling for C++ exceptions
+/// and JavaScript exceptions.
+///
+/// If a Node-API call fails without executing any JavaScript code (for
+/// example due to an invalid argument), then the Node-API wrapper
+/// automatically converts and throws the error as a C++ exception of type
+/// `Napi::Error`. Or if a JavaScript function called by C++ code via Node-API
+/// throws a JavaScript exception, then the Node-API wrapper automatically
+/// converts and throws it as a C++ exception of type `Napi::Error`.
+///
+/// If a C++ exception of type `Napi::Error` escapes from a Node-API C++
+/// callback, then the Node-API wrapper automatically converts and throws it
+/// as a JavaScript exception. Therefore, catching a C++ exception of type
+/// `Napi::Error` prevents a JavaScript exception from being thrown.
+///
+/// #### Example 1A - Throwing a C++ exception:
+///
+///     Napi::Env env = ...
+///     throw Napi::Error::New(env, "Example exception");
+///
+/// Following C++ statements will not be executed. The exception will bubble
+/// up as a C++ exception of type `Napi::Error`, until it is either caught
+/// while still in C++, or else automatically propataged as a JavaScript
+/// exception when the callback returns to JavaScript.
+///
+/// #### Example 2A - Propagating a Node-API C++ exception:
+///
+///     Napi::Function jsFunctionThatThrows = someObj.As<Napi::Function>();
+///     Napi::Value result = jsFunctionThatThrows({ arg1, arg2 });
+///
+/// Following C++ statements will not be executed. The exception will bubble
+/// up as a C++ exception of type `Napi::Error`, until it is either caught
+/// while still in C++, or else automatically propagated as a JavaScript
+/// exception when the callback returns to JavaScript.
+///
+/// #### Example 3A - Handling a Node-API C++ exception:
+///
+///     Napi::Function jsFunctionThatThrows = someObj.As<Napi::Function>();
+///     Napi::Value result;
+///     try {
+///        result = jsFunctionThatThrows({ arg1, arg2 });
+///     } catch (const Napi::Error& e) {
+///       cerr << "Caught JavaScript exception: " + e.what();
+///     }
+///
+/// Since the exception was caught here, it will not be propagated as a
+/// JavaScript exception.
+///
+/// ### Handling Errors Without C++ Exceptions
+///
+/// If C++ exceptions are disabled (by defining `NAPI_DISABLE_CPP_EXCEPTIONS`)
+/// then this class does not extend `std::exception`, and APIs in the `Napi`
+/// namespace do not throw C++ exceptions when they fail. Instead, they raise
+/// _pending_ JavaScript exceptions and return _empty_ `Value`s. Calling code
+/// should check `Value::IsEmpty()` before attempting to use a returned value,
+/// and may use methods on the `Env` class to check for, get, and clear a
+/// pending JavaScript exception. If the pending exception is not cleared, it
+/// will be thrown when the native callback returns to JavaScript.
+///
+/// #### Example 1B - Throwing a JS exception
+///
+///     Napi::Env env = ...
+///     Napi::Error::New(env, "Example
+///     exception").ThrowAsJavaScriptException(); return;
+///
+/// After throwing a JS exception, the code should generally return
+/// immediately from the native callback, after performing any necessary
+/// cleanup.
+///
+/// #### Example 2B - Propagating a Node-API JS exception:
+///
+///     Napi::Function jsFunctionThatThrows = someObj.As<Napi::Function>();
+///     Napi::Value result = jsFunctionThatThrows({ arg1, arg2 });
+///     if (result.IsEmpty()) return;
+///
+/// An empty value result from a Node-API call indicates an error occurred,
+/// and a JavaScript exception is pending. To let the exception propagate, the
+/// code should generally return immediately from the native callback, after
+/// performing any necessary cleanup.
+///
+/// #### Example 3B - Handling a Node-API JS exception:
+///
+///     Napi::Function jsFunctionThatThrows = someObj.As<Napi::Function>();
+///     Napi::Value result = jsFunctionThatThrows({ arg1, arg2 });
+///     if (result.IsEmpty()) {
+///       Napi::Error e = env.GetAndClearPendingException();
+///       cerr << "Caught JavaScript exception: " + e.Message();
+///     }
+///
+/// Since the exception was cleared here, it will not be propagated as a
+/// JavaScript exception after the native callback returns.
+class Error : public ObjectReference
+#ifdef NAPI_CPP_EXCEPTIONS
+    ,
+              public std::exception
+#endif  // NAPI_CPP_EXCEPTIONS
+{
+ public:
+  static Error New(napi_env env);
+  static Error New(napi_env env, const char* message);
+  static Error New(napi_env env, const std::string& message);
+
+  static NAPI_NO_RETURN void Fatal(const char* location, const char* message);
+
+  Error();
+  Error(napi_env env, napi_value value);
+
+  // An error can be moved or copied.
+  Error(Error&& other);
+  Error& operator=(Error&& other);
+  Error(const Error&);
+  Error& operator=(const Error&);
+
+  const std::string& Message() const NAPI_NOEXCEPT;
+  void ThrowAsJavaScriptException() const;
+
+  Object Value() const;
+
+#ifdef NAPI_CPP_EXCEPTIONS
+  const char* what() const NAPI_NOEXCEPT override;
+#endif  // NAPI_CPP_EXCEPTIONS
+
+ protected:
+  /// !cond INTERNAL
+  using create_error_fn = napi_status (*)(napi_env envb,
+                                          napi_value code,
+                                          napi_value msg,
+                                          napi_value* result);
+
+  template <typename TError>
+  static TError New(napi_env env,
+                    const char* message,
+                    size_t length,
+                    create_error_fn create_error);
+  /// !endcond
+
+ private:
+  static inline const char* ERROR_WRAP_VALUE() NAPI_NOEXCEPT;
+  mutable std::string _message;
+};
+
+class TypeError : public Error {
+ public:
+  static TypeError New(napi_env env, const char* message);
+  static TypeError New(napi_env env, const std::string& message);
+
+  TypeError();
+  TypeError(napi_env env, napi_value value);
+};
+
+class RangeError : public Error {
+ public:
+  static RangeError New(napi_env env, const char* message);
+  static RangeError New(napi_env env, const std::string& message);
+
+  RangeError();
+  RangeError(napi_env env, napi_value value);
+};
+
+#if NAPI_VERSION > 8
+class SyntaxError : public Error {
+ public:
+  static SyntaxError New(napi_env env, const char* message);
+  static SyntaxError New(napi_env env, const std::string& message);
+
+  SyntaxError();
+  SyntaxError(napi_env env, napi_value value);
+};
+#endif  // NAPI_VERSION > 8
+
+class CallbackInfo {
+ public:
+  CallbackInfo(napi_env env, napi_callback_info info);
+  ~CallbackInfo();
+
+  // Disallow copying to prevent multiple free of _dynamicArgs
+  NAPI_DISALLOW_ASSIGN_COPY(CallbackInfo)
+
+  Napi::Env Env() const;
+  Value NewTarget() const;
+  bool IsConstructCall() const;
+  size_t Length() const;
+  const Value operator[](size_t index) const;
+  Value This() const;
+  void* Data() const;
+  void SetData(void* data);
+  explicit operator napi_callback_info() const;
+
+ private:
+  const size_t _staticArgCount = 6;
+  napi_env _env;
+  napi_callback_info _info;
+  napi_value _this;
+  size_t _argc;
+  napi_value* _argv;
+  napi_value _staticArgs[6];
+  napi_value* _dynamicArgs;
+  void* _data;
+};
+
+class PropertyDescriptor {
+ public:
+  using GetterCallback = Napi::Value (*)(const Napi::CallbackInfo& info);
+  using SetterCallback = void (*)(const Napi::CallbackInfo& info);
+
+#ifndef NODE_ADDON_API_DISABLE_DEPRECATED
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      const char* utf8name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      const std::string& utf8name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      napi_value name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      Name name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      const char* utf8name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      const std::string& utf8name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      napi_value name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      Name name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      const char* utf8name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      const std::string& utf8name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      napi_value name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      Name name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+#endif  // !NODE_ADDON_API_DISABLE_DEPRECATED
+
+  template <GetterCallback Getter>
+  static PropertyDescriptor Accessor(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter>
+  static PropertyDescriptor Accessor(
+      const std::string& utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter>
+  static PropertyDescriptor Accessor(
+      Name name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter, SetterCallback Setter>
+  static PropertyDescriptor Accessor(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter, SetterCallback Setter>
+  static PropertyDescriptor Accessor(
+      const std::string& utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <GetterCallback Getter, SetterCallback Setter>
+  static PropertyDescriptor Accessor(
+      Name name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      const char* utf8name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      const std::string& utf8name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      Name name,
+      Getter getter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      const char* utf8name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      const std::string& utf8name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Getter, typename Setter>
+  static PropertyDescriptor Accessor(
+      Napi::Env env,
+      Napi::Object object,
+      Name name,
+      Getter getter,
+      Setter setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      Napi::Env env,
+      Napi::Object object,
+      const char* utf8name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      Napi::Env env,
+      Napi::Object object,
+      const std::string& utf8name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <typename Callable>
+  static PropertyDescriptor Function(
+      Napi::Env env,
+      Napi::Object object,
+      Name name,
+      Callable cb,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor Value(
+      const char* utf8name,
+      napi_value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor Value(
+      const std::string& utf8name,
+      napi_value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor Value(
+      napi_value name,
+      napi_value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor Value(
+      Name name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+
+  PropertyDescriptor(napi_property_descriptor desc);
+
+  operator napi_property_descriptor&();
+  operator const napi_property_descriptor&() const;
+
+ private:
+  napi_property_descriptor _desc;
+};
+
+/// Property descriptor for use with `ObjectWrap::DefineClass()`.
+///
+/// This is different from the standalone `PropertyDescriptor` because it is
+/// specific to each `ObjectWrap<T>` subclass. This prevents using descriptors
+/// from a different class when defining a new class (preventing the callbacks
+/// from having incorrect `this` pointers).
+template <typename T>
+class ClassPropertyDescriptor {
+ public:
+  ClassPropertyDescriptor(napi_property_descriptor desc) : _desc(desc) {}
+
+  operator napi_property_descriptor&() { return _desc; }
+  operator const napi_property_descriptor&() const { return _desc; }
+
+ private:
+  napi_property_descriptor _desc;
+};
+
+template <typename T, typename TCallback>
+struct MethodCallbackData {
+  TCallback callback;
+  void* data;
+};
+
+template <typename T, typename TGetterCallback, typename TSetterCallback>
+struct AccessorCallbackData {
+  TGetterCallback getterCallback;
+  TSetterCallback setterCallback;
+  void* data;
+};
+
+template <typename T>
+class InstanceWrap {
+ public:
+  using InstanceVoidMethodCallback = void (T::*)(const CallbackInfo& info);
+  using InstanceMethodCallback = Napi::Value (T::*)(const CallbackInfo& info);
+  using InstanceGetterCallback = Napi::Value (T::*)(const CallbackInfo& info);
+  using InstanceSetterCallback = void (T::*)(const CallbackInfo& info,
+                                             const Napi::Value& value);
+
+  using PropertyDescriptor = ClassPropertyDescriptor<T>;
+
+  static PropertyDescriptor InstanceMethod(
+      const char* utf8name,
+      InstanceVoidMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceMethod(
+      const char* utf8name,
+      InstanceMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceMethod(
+      Symbol name,
+      InstanceVoidMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceMethod(
+      Symbol name,
+      InstanceMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceVoidMethodCallback method>
+  static PropertyDescriptor InstanceMethod(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceMethodCallback method>
+  static PropertyDescriptor InstanceMethod(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceVoidMethodCallback method>
+  static PropertyDescriptor InstanceMethod(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceMethodCallback method>
+  static PropertyDescriptor InstanceMethod(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceAccessor(
+      const char* utf8name,
+      InstanceGetterCallback getter,
+      InstanceSetterCallback setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceAccessor(
+      Symbol name,
+      InstanceGetterCallback getter,
+      InstanceSetterCallback setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceGetterCallback getter,
+            InstanceSetterCallback setter = nullptr>
+  static PropertyDescriptor InstanceAccessor(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <InstanceGetterCallback getter,
+            InstanceSetterCallback setter = nullptr>
+  static PropertyDescriptor InstanceAccessor(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor InstanceValue(
+      const char* utf8name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor InstanceValue(
+      Symbol name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+
+ protected:
+  static void AttachPropData(napi_env env,
+                             napi_value value,
+                             const napi_property_descriptor* prop);
+
+ private:
+  using This = InstanceWrap<T>;
+
+  using InstanceVoidMethodCallbackData =
+      MethodCallbackData<T, InstanceVoidMethodCallback>;
+  using InstanceMethodCallbackData =
+      MethodCallbackData<T, InstanceMethodCallback>;
+  using InstanceAccessorCallbackData =
+      AccessorCallbackData<T, InstanceGetterCallback, InstanceSetterCallback>;
+
+  static napi_value InstanceVoidMethodCallbackWrapper(napi_env env,
+                                                      napi_callback_info info);
+  static napi_value InstanceMethodCallbackWrapper(napi_env env,
+                                                  napi_callback_info info);
+  static napi_value InstanceGetterCallbackWrapper(napi_env env,
+                                                  napi_callback_info info);
+  static napi_value InstanceSetterCallbackWrapper(napi_env env,
+                                                  napi_callback_info info);
+
+  template <InstanceSetterCallback method>
+  static napi_value WrappedMethod(napi_env env,
+                                  napi_callback_info info) NAPI_NOEXCEPT;
+
+  template <InstanceSetterCallback setter>
+  struct SetterTag {};
+
+  template <InstanceSetterCallback setter>
+  static napi_callback WrapSetter(SetterTag<setter>) NAPI_NOEXCEPT {
+    return &This::WrappedMethod<setter>;
+  }
+  static napi_callback WrapSetter(SetterTag<nullptr>) NAPI_NOEXCEPT {
+    return nullptr;
+  }
+};
+
+/// Base class to be extended by C++ classes exposed to JavaScript; each C++
+/// class instance gets "wrapped" by a JavaScript object that is managed by this
+/// class.
+///
+/// At initialization time, the `DefineClass()` method must be used to
+/// hook up the accessor and method callbacks. It takes a list of
+/// property descriptors, which can be constructed via the various
+/// static methods on the base class.
+///
+/// #### Example:
+///
+///     class Example: public Napi::ObjectWrap<Example> {
+///       public:
+///         static void Initialize(Napi::Env& env, Napi::Object& target) {
+///           Napi::Function constructor = DefineClass(env, "Example", {
+///             InstanceAccessor<&Example::GetSomething,
+///             &Example::SetSomething>("value"),
+///             InstanceMethod<&Example::DoSomething>("doSomething"),
+///           });
+///           target.Set("Example", constructor);
+///         }
+///
+///         Example(const Napi::CallbackInfo& info); // Constructor
+///         Napi::Value GetSomething(const Napi::CallbackInfo& info);
+///         void SetSomething(const Napi::CallbackInfo& info, const Napi::Value&
+///         value); Napi::Value DoSomething(const Napi::CallbackInfo& info);
+///     }
+template <typename T>
+class ObjectWrap : public InstanceWrap<T>, public Reference<Object> {
+ public:
+  ObjectWrap(const CallbackInfo& callbackInfo);
+  virtual ~ObjectWrap();
+
+  static T* Unwrap(Object wrapper);
+
+  // Methods exposed to JavaScript must conform to one of these callback
+  // signatures.
+  using StaticVoidMethodCallback = void (*)(const CallbackInfo& info);
+  using StaticMethodCallback = Napi::Value (*)(const CallbackInfo& info);
+  using StaticGetterCallback = Napi::Value (*)(const CallbackInfo& info);
+  using StaticSetterCallback = void (*)(const CallbackInfo& info,
+                                        const Napi::Value& value);
+
+  using PropertyDescriptor = ClassPropertyDescriptor<T>;
+
+  static Function DefineClass(
+      Napi::Env env,
+      const char* utf8name,
+      const std::initializer_list<PropertyDescriptor>& properties,
+      void* data = nullptr);
+  static Function DefineClass(Napi::Env env,
+                              const char* utf8name,
+                              const std::vector<PropertyDescriptor>& properties,
+                              void* data = nullptr);
+  static PropertyDescriptor StaticMethod(
+      const char* utf8name,
+      StaticVoidMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticMethod(
+      const char* utf8name,
+      StaticMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticMethod(
+      Symbol name,
+      StaticVoidMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticMethod(
+      Symbol name,
+      StaticMethodCallback method,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticVoidMethodCallback method>
+  static PropertyDescriptor StaticMethod(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticVoidMethodCallback method>
+  static PropertyDescriptor StaticMethod(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticMethodCallback method>
+  static PropertyDescriptor StaticMethod(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticMethodCallback method>
+  static PropertyDescriptor StaticMethod(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticAccessor(
+      const char* utf8name,
+      StaticGetterCallback getter,
+      StaticSetterCallback setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticAccessor(
+      Symbol name,
+      StaticGetterCallback getter,
+      StaticSetterCallback setter,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticGetterCallback getter, StaticSetterCallback setter = nullptr>
+  static PropertyDescriptor StaticAccessor(
+      const char* utf8name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  template <StaticGetterCallback getter, StaticSetterCallback setter = nullptr>
+  static PropertyDescriptor StaticAccessor(
+      Symbol name,
+      napi_property_attributes attributes = napi_default,
+      void* data = nullptr);
+  static PropertyDescriptor StaticValue(
+      const char* utf8name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+  static PropertyDescriptor StaticValue(
+      Symbol name,
+      Napi::Value value,
+      napi_property_attributes attributes = napi_default);
+  static Napi::Value OnCalledAsFunction(const Napi::CallbackInfo& callbackInfo);
+  virtual void Finalize(Napi::Env env);
+
+ private:
+  using This = ObjectWrap<T>;
+
+  static napi_value ConstructorCallbackWrapper(napi_env env,
+                                               napi_callback_info info);
+  static napi_value StaticVoidMethodCallbackWrapper(napi_env env,
+                                                    napi_callback_info info);
+  static napi_value StaticMethodCallbackWrapper(napi_env env,
+                                                napi_callback_info info);
+  static napi_value StaticGetterCallbackWrapper(napi_env env,
+                                                napi_callback_info info);
+  static napi_value StaticSetterCallbackWrapper(napi_env env,
+                                                napi_callback_info info);
+  static void FinalizeCallback(napi_env env, void* data, void* hint);
+  static Function DefineClass(Napi::Env env,
+                              const char* utf8name,
+                              const size_t props_count,
+                              const napi_property_descriptor* props,
+                              void* data = nullptr);
+
+  using StaticVoidMethodCallbackData =
+      MethodCallbackData<T, StaticVoidMethodCallback>;
+  using StaticMethodCallbackData = MethodCallbackData<T, StaticMethodCallback>;
+
+  using StaticAccessorCallbackData =
+      AccessorCallbackData<T, StaticGetterCallback, StaticSetterCallback>;
+
+  template <StaticSetterCallback method>
+  static napi_value WrappedMethod(napi_env env,
+                                  napi_callback_info info) NAPI_NOEXCEPT;
+
+  template <StaticSetterCallback setter>
+  struct StaticSetterTag {};
+
+  template <StaticSetterCallback setter>
+  static napi_callback WrapStaticSetter(StaticSetterTag<setter>) NAPI_NOEXCEPT {
+    return &This::WrappedMethod<setter>;
+  }
+  static napi_callback WrapStaticSetter(StaticSetterTag<nullptr>)
+      NAPI_NOEXCEPT {
+    return nullptr;
+  }
+
+  bool _construction_failed = true;
+};
+
+class HandleScope {
+ public:
+  HandleScope(napi_env env, napi_handle_scope scope);
+  explicit HandleScope(Napi::Env env);
+  ~HandleScope();
+
+  // Disallow copying to prevent double close of napi_handle_scope
+  NAPI_DISALLOW_ASSIGN_COPY(HandleScope)
+
+  operator napi_handle_scope() const;
+
+  Napi::Env Env() const;
+
+ private:
+  napi_env _env;
+  napi_handle_scope _scope;
+};
+
+class EscapableHandleScope {
+ public:
+  EscapableHandleScope(napi_env env, napi_escapable_handle_scope scope);
+  explicit EscapableHandleScope(Napi::Env env);
+  ~EscapableHandleScope();
+
+  // Disallow copying to prevent double close of napi_escapable_handle_scope
+  NAPI_DISALLOW_ASSIGN_COPY(EscapableHandleScope)
+
+  operator napi_escapable_handle_scope() const;
+
+  Napi::Env Env() const;
+  Value Escape(napi_value escapee);
+
+ private:
+  napi_env _env;
+  napi_escapable_handle_scope _scope;
+};
+
+#if (NAPI_VERSION > 2)
+class CallbackScope {
+ public:
+  CallbackScope(napi_env env, napi_callback_scope scope);
+  CallbackScope(napi_env env, napi_async_context context);
+  virtual ~CallbackScope();
+
+  // Disallow copying to prevent double close of napi_callback_scope
+  NAPI_DISALLOW_ASSIGN_COPY(CallbackScope)
+
+  operator napi_callback_scope() const;
+
+  Napi::Env Env() const;
+
+ private:
+  napi_env _env;
+  napi_callback_scope _scope;
+};
+#endif
+
+class AsyncContext {
+ public:
+  explicit AsyncContext(napi_env env, const char* resource_name);
+  explicit AsyncContext(napi_env env,
+                        const char* resource_name,
+                        const Object& resource);
+  virtual ~AsyncContext();
+
+  AsyncContext(AsyncContext&& other);
+  AsyncContext& operator=(AsyncContext&& other);
+  NAPI_DISALLOW_ASSIGN_COPY(AsyncContext)
+
+  operator napi_async_context() const;
+
+  Napi::Env Env() const;
+
+ private:
+  napi_env _env;
+  napi_async_context _context;
+};
+
+#if NAPI_HAS_THREADS
+class AsyncWorker {
+ public:
+  virtual ~AsyncWorker();
+
+  NAPI_DISALLOW_ASSIGN_COPY(AsyncWorker)
+
+  operator napi_async_work() const;
+
+  Napi::Env Env() const;
+
+  void Queue();
+  void Cancel();
+  void SuppressDestruct();
+
+  ObjectReference& Receiver();
+  FunctionReference& Callback();
+
+  virtual void OnExecute(Napi::Env env);
+  virtual void OnWorkComplete(Napi::Env env, napi_status status);
+
+ protected:
+  explicit AsyncWorker(const Function& callback);
+  explicit AsyncWorker(const Function& callback, const char* resource_name);
+  explicit AsyncWorker(const Function& callback,
+                       const char* resource_name,
+                       const Object& resource);
+  explicit AsyncWorker(const Object& receiver, const Function& callback);
+  explicit AsyncWorker(const Object& receiver,
+                       const Function& callback,
+                       const char* resource_name);
+  explicit AsyncWorker(const Object& receiver,
+                       const Function& callback,
+                       const char* resource_name,
+                       const Object& resource);
+
+  explicit AsyncWorker(Napi::Env env);
+  explicit AsyncWorker(Napi::Env env, const char* resource_name);
+  explicit AsyncWorker(Napi::Env env,
+                       const char* resource_name,
+                       const Object& resource);
+
+  virtual void Execute() = 0;
+  virtual void OnOK();
+  virtual void OnError(const Error& e);
+  virtual void Destroy();
+  virtual std::vector<napi_value> GetResult(Napi::Env env);
+
+  void SetError(const std::string& error);
+
+ private:
+  static inline void OnAsyncWorkExecute(napi_env env, void* asyncworker);
+  static inline void OnAsyncWorkComplete(napi_env env,
+                                         napi_status status,
+                                         void* asyncworker);
+
+  napi_env _env;
+  napi_async_work _work;
+  ObjectReference _receiver;
+  FunctionReference _callback;
+  std::string _error;
+  bool _suppress_destruct;
+};
+#endif  // NAPI_HAS_THREADS
+
+#if (NAPI_VERSION > 3 && NAPI_HAS_THREADS)
+class ThreadSafeFunction {
+ public:
+  // This API may only be called from the main thread.
+  template <typename ResourceString>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename ContextType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename Finalizer>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                Finalizer finalizeCallback);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename ContextType, typename Finalizer>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString,
+            typename ContextType,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename ContextType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename Finalizer>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                Finalizer finalizeCallback);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString, typename ContextType, typename Finalizer>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback);
+
+  // This API may only be called from the main thread.
+  template <typename ResourceString,
+            typename ContextType,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data);
+
+  ThreadSafeFunction();
+  ThreadSafeFunction(napi_threadsafe_function tsFunctionValue);
+
+  operator napi_threadsafe_function() const;
+
+  // This API may be called from any thread.
+  napi_status BlockingCall() const;
+
+  // This API may be called from any thread.
+  template <typename Callback>
+  napi_status BlockingCall(Callback callback) const;
+
+  // This API may be called from any thread.
+  template <typename DataType, typename Callback>
+  napi_status BlockingCall(DataType* data, Callback callback) const;
+
+  // This API may be called from any thread.
+  napi_status NonBlockingCall() const;
+
+  // This API may be called from any thread.
+  template <typename Callback>
+  napi_status NonBlockingCall(Callback callback) const;
+
+  // This API may be called from any thread.
+  template <typename DataType, typename Callback>
+  napi_status NonBlockingCall(DataType* data, Callback callback) const;
+
+  // This API may only be called from the main thread.
+  void Ref(napi_env env) const;
+
+  // This API may only be called from the main thread.
+  void Unref(napi_env env) const;
+
+  // This API may be called from any thread.
+  napi_status Acquire() const;
+
+  // This API may be called from any thread.
+  napi_status Release() const;
+
+  // This API may be called from any thread.
+  napi_status Abort() const;
+
+  struct ConvertibleContext {
+    template <class T>
+    operator T*() {
+      return static_cast<T*>(context);
+    }
+    void* context;
+  };
+
+  // This API may be called from any thread.
+  ConvertibleContext GetContext() const;
+
+ private:
+  using CallbackWrapper = std::function<void(Napi::Env, Napi::Function)>;
+
+  template <typename ResourceString,
+            typename ContextType,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static ThreadSafeFunction New(napi_env env,
+                                const Function& callback,
+                                const Object& resource,
+                                ResourceString resourceName,
+                                size_t maxQueueSize,
+                                size_t initialThreadCount,
+                                ContextType* context,
+                                Finalizer finalizeCallback,
+                                FinalizerDataType* data,
+                                napi_finalize wrapper);
+
+  napi_status CallInternal(CallbackWrapper* callbackWrapper,
+                           napi_threadsafe_function_call_mode mode) const;
+
+  static void CallJS(napi_env env,
+                     napi_value jsCallback,
+                     void* context,
+                     void* data);
+
+  napi_threadsafe_function _tsfn;
+};
+
+// A TypedThreadSafeFunction by default has no context (nullptr) and can
+// accept any type (void) to its CallJs.
+template <typename ContextType = std::nullptr_t,
+          typename DataType = void,
+          void (*CallJs)(Napi::Env, Napi::Function, ContextType*, DataType*) =
+              nullptr>
+class TypedThreadSafeFunction {
+ public:
+  // This API may only be called from the main thread.
+  // Helper function that returns nullptr if running Node-API 5+, otherwise a
+  // non-empty, no-op Function. This provides the ability to specify at
+  // compile-time a callback parameter to `New` that safely does no action
+  // when targeting _any_ Node-API version.
+#if NAPI_VERSION > 4
+  static std::nullptr_t EmptyFunctionFactory(Napi::Env env);
+#else
+  static Napi::Function EmptyFunctionFactory(Napi::Env env);
+#endif
+  static Napi::Function FunctionOrEmpty(Napi::Env env,
+                                        Napi::Function& callback);
+
+#if NAPI_VERSION > 4
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [missing] Resource [missing] Finalizer [missing]
+  template <typename ResourceString>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [missing] Resource [passed] Finalizer [missing]
+  template <typename ResourceString>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [missing] Resource [missing] Finalizer [passed]
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType = void>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [missing] Resource [passed] Finalizer [passed]
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType = void>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data = nullptr);
+#endif
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [passed] Resource [missing] Finalizer [missing]
+  template <typename ResourceString>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Function& callback,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [passed] Resource [passed] Finalizer [missing]
+  template <typename ResourceString>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Function& callback,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [passed] Resource [missing] Finalizer [passed]
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType = void>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Function& callback,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data = nullptr);
+
+  // This API may only be called from the main thread.
+  // Creates a new threadsafe function with:
+  //   Callback [passed] Resource [passed] Finalizer [passed]
+  template <typename CallbackType,
+            typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      CallbackType callback,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data = nullptr);
+
+  TypedThreadSafeFunction();
+  TypedThreadSafeFunction(napi_threadsafe_function tsFunctionValue);
+
+  operator napi_threadsafe_function() const;
+
+  // This API may be called from any thread.
+  napi_status BlockingCall(DataType* data = nullptr) const;
+
+  // This API may be called from any thread.
+  napi_status NonBlockingCall(DataType* data = nullptr) const;
+
+  // This API may only be called from the main thread.
+  void Ref(napi_env env) const;
+
+  // This API may only be called from the main thread.
+  void Unref(napi_env env) const;
+
+  // This API may be called from any thread.
+  napi_status Acquire() const;
+
+  // This API may be called from any thread.
+  napi_status Release() const;
+
+  // This API may be called from any thread.
+  napi_status Abort() const;
+
+  // This API may be called from any thread.
+  ContextType* GetContext() const;
+
+ private:
+  template <typename ResourceString,
+            typename Finalizer,
+            typename FinalizerDataType>
+  static TypedThreadSafeFunction<ContextType, DataType, CallJs> New(
+      napi_env env,
+      const Function& callback,
+      const Object& resource,
+      ResourceString resourceName,
+      size_t maxQueueSize,
+      size_t initialThreadCount,
+      ContextType* context,
+      Finalizer finalizeCallback,
+      FinalizerDataType* data,
+      napi_finalize wrapper);
+
+  static void CallJsInternal(napi_env env,
+                             napi_value jsCallback,
+                             void* context,
+                             void* data);
+
+ protected:
+  napi_threadsafe_function _tsfn;
+};
+template <typename DataType>
+class AsyncProgressWorkerBase : public AsyncWorker {
+ public:
+  virtual void OnWorkProgress(DataType* data) = 0;
+  class ThreadSafeData {
+   public:
+    ThreadSafeData(AsyncProgressWorkerBase* asyncprogressworker, DataType* data)
+        : _asyncprogressworker(asyncprogressworker), _data(data) {}
+
+    AsyncProgressWorkerBase* asyncprogressworker() {
+      return _asyncprogressworker;
+    };
+    DataType* data() { return _data; };
+
+   private:
+    AsyncProgressWorkerBase* _asyncprogressworker;
+    DataType* _data;
+  };
+  void OnWorkComplete(Napi::Env env, napi_status status) override;
+
+ protected:
+  explicit AsyncProgressWorkerBase(const Object& receiver,
+                                   const Function& callback,
+                                   const char* resource_name,
+                                   const Object& resource,
+                                   size_t queue_size = 1);
+  virtual ~AsyncProgressWorkerBase();
+
+// Optional callback of Napi::ThreadSafeFunction only available after
+// NAPI_VERSION 4. Refs: https://github.com/nodejs/node/pull/27791
+#if NAPI_VERSION > 4
+  explicit AsyncProgressWorkerBase(Napi::Env env,
+                                   const char* resource_name,
+                                   const Object& resource,
+                                   size_t queue_size = 1);
+#endif
+
+  static inline void OnAsyncWorkProgress(Napi::Env env,
+                                         Napi::Function jsCallback,
+                                         void* data);
+
+  napi_status NonBlockingCall(DataType* data);
+
+ private:
+  ThreadSafeFunction _tsfn;
+  bool _work_completed = false;
+  napi_status _complete_status;
+  static inline void OnThreadSafeFunctionFinalize(
+      Napi::Env env, void* data, AsyncProgressWorkerBase* context);
+};
+
+template <class T>
+class AsyncProgressWorker : public AsyncProgressWorkerBase<void> {
+ public:
+  virtual ~AsyncProgressWorker();
+
+  class ExecutionProgress {
+    friend class AsyncProgressWorker;
+
+   public:
+    void Signal() const;
+    void Send(const T* data, size_t count) const;
+
+   private:
+    explicit ExecutionProgress(AsyncProgressWorker* worker) : _worker(worker) {}
+    AsyncProgressWorker* const _worker;
+  };
+
+  void OnWorkProgress(void*) override;
+
+ protected:
+  explicit AsyncProgressWorker(const Function& callback);
+  explicit AsyncProgressWorker(const Function& callback,
+                               const char* resource_name);
+  explicit AsyncProgressWorker(const Function& callback,
+                               const char* resource_name,
+                               const Object& resource);
+  explicit AsyncProgressWorker(const Object& receiver,
+                               const Function& callback);
+  explicit AsyncProgressWorker(const Object& receiver,
+                               const Function& callback,
+                               const char* resource_name);
+  explicit AsyncProgressWorker(const Object& receiver,
+                               const Function& callback,
+                               const char* resource_name,
+                               const Object& resource);
+
+// Optional callback of Napi::ThreadSafeFunction only available after
+// NAPI_VERSION 4. Refs: https://github.com/nodejs/node/pull/27791
+#if NAPI_VERSION > 4
+  explicit AsyncProgressWorker(Napi::Env env);
+  explicit AsyncProgressWorker(Napi::Env env, const char* resource_name);
+  explicit AsyncProgressWorker(Napi::Env env,
+                               const char* resource_name,
+                               const Object& resource);
+#endif
+  virtual void Execute(const ExecutionProgress& progress) = 0;
+  virtual void OnProgress(const T* data, size_t count) = 0;
+
+ private:
+  void Execute() override;
+  void Signal();
+  void SendProgress_(const T* data, size_t count);
+
+  std::mutex _mutex;
+  T* _asyncdata;
+  size_t _asyncsize;
+  bool _signaled;
+};
+
+template <class T>
+class AsyncProgressQueueWorker
+    : public AsyncProgressWorkerBase<std::pair<T*, size_t>> {
+ public:
+  virtual ~AsyncProgressQueueWorker(){};
+
+  class ExecutionProgress {
+    friend class AsyncProgressQueueWorker;
+
+   public:
+    void Signal() const;
+    void Send(const T* data, size_t count) const;
+
+   private:
+    explicit ExecutionProgress(AsyncProgressQueueWorker* worker)
+        : _worker(worker) {}
+    AsyncProgressQueueWorker* const _worker;
+  };
+
+  void OnWorkComplete(Napi::Env env, napi_status status) override;
+  void OnWorkProgress(std::pair<T*, size_t>*) override;
+
+ protected:
+  explicit AsyncProgressQueueWorker(const Function& callback);
+  explicit AsyncProgressQueueWorker(const Function& callback,
+                                    const char* resource_name);
+  explicit AsyncProgressQueueWorker(const Function& callback,
+                                    const char* resource_name,
+                                    const Object& resource);
+  explicit AsyncProgressQueueWorker(const Object& receiver,
+                                    const Function& callback);
+  explicit AsyncProgressQueueWorker(const Object& receiver,
+                                    const Function& callback,
+                                    const char* resource_name);
+  explicit AsyncProgressQueueWorker(const Object& receiver,
+                                    const Function& callback,
+                                    const char* resource_name,
+                                    const Object& resource);
+
+// Optional callback of Napi::ThreadSafeFunction only available after
+// NAPI_VERSION 4. Refs: https://github.com/nodejs/node/pull/27791
+#if NAPI_VERSION > 4
+  explicit AsyncProgressQueueWorker(Napi::Env env);
+  explicit AsyncProgressQueueWorker(Napi::Env env, const char* resource_name);
+  explicit AsyncProgressQueueWorker(Napi::Env env,
+                                    const char* resource_name,
+                                    const Object& resource);
+#endif
+  virtual void Execute(const ExecutionProgress& progress) = 0;
+  virtual void OnProgress(const T* data, size_t count) = 0;
+
+ private:
+  void Execute() override;
+  void Signal() const;
+  void SendProgress_(const T* data, size_t count);
+};
+#endif  // NAPI_VERSION > 3 && NAPI_HAS_THREADS
+
+// Memory management.
+class MemoryManagement {
+ public:
+  static int64_t AdjustExternalMemory(Env env, int64_t change_in_bytes);
+};
+
+// Version management
+class VersionManagement {
+ public:
+  static uint32_t GetNapiVersion(Env env);
+  static const napi_node_version* GetNodeVersion(Env env);
+};
+
+#if NAPI_VERSION > 5
+template <typename T>
+class Addon : public InstanceWrap<T> {
+ public:
+  static inline Object Init(Env env, Object exports);
+  static T* Unwrap(Object wrapper);
+
+ protected:
+  using AddonProp = ClassPropertyDescriptor<T>;
+  void DefineAddon(Object exports,
+                   const std::initializer_list<AddonProp>& props);
+  Napi::Object DefineProperties(Object object,
+                                const std::initializer_list<AddonProp>& props);
+
+ private:
+  Object entry_point_;
+};
+#endif  // NAPI_VERSION > 5
+
+#ifdef NAPI_CPP_CUSTOM_NAMESPACE
+}  // namespace NAPI_CPP_CUSTOM_NAMESPACE
+#endif
+
+}  // namespace Napi
+
+// Inline implementations of all the above class methods are included here.
+#include "napi-inl.h"
+
+#endif  // SRC_NAPI_H_
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/node_addon_api.gyp b/server/node_modules/sqlite3/node_modules/node-addon-api/node_addon_api.gyp
new file mode 100644
index 0000000..29905ed
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/node_addon_api.gyp
@@ -0,0 +1,32 @@
+{
+  'targets': [
+    {
+      'target_name': 'node_addon_api',
+      'type': 'none',
+      'sources': [ 'napi.h', 'napi-inl.h' ],
+      'direct_dependent_settings': {
+        'include_dirs': [ '.' ],
+        'includes': ['noexcept.gypi'],
+      }
+    },
+    {
+      'target_name': 'node_addon_api_except',
+      'type': 'none',
+      'sources': [ 'napi.h', 'napi-inl.h' ],
+      'direct_dependent_settings': {
+        'include_dirs': [ '.' ],
+        'includes': ['except.gypi'],
+      }
+    },
+    {
+      'target_name': 'node_addon_api_maybe',
+      'type': 'none',
+      'sources': [ 'napi.h', 'napi-inl.h' ],
+      'direct_dependent_settings': {
+        'include_dirs': [ '.' ],
+        'includes': ['noexcept.gypi'],
+        'defines': ['NODE_ADDON_API_ENABLE_MAYBE']
+      }
+    },
+  ]
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/node_api.gyp b/server/node_modules/sqlite3/node_modules/node-addon-api/node_api.gyp
new file mode 100644
index 0000000..4ff0ae7
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/node_api.gyp
@@ -0,0 +1,9 @@
+{
+  'targets': [
+    {
+      'target_name': 'nothing',
+      'type': 'static_library',
+      'sources': [ 'nothing.c' ]
+    }
+  ]
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/noexcept.gypi b/server/node_modules/sqlite3/node_modules/node-addon-api/noexcept.gypi
new file mode 100644
index 0000000..404a05f
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/noexcept.gypi
@@ -0,0 +1,26 @@
+{
+  'defines': [ 'NAPI_DISABLE_CPP_EXCEPTIONS' ],
+  'cflags': [ '-fno-exceptions' ],
+  'cflags_cc': [ '-fno-exceptions' ],
+  'conditions': [
+    ["OS=='win'", {
+      # _HAS_EXCEPTIONS is already defined and set to 0 in common.gypi
+      #"defines": [
+      #  "_HAS_EXCEPTIONS=0"
+      #],
+      "msvs_settings": {
+        "VCCLCompilerTool": {
+          'ExceptionHandling': 0,
+          'EnablePREfast': 'true',
+        },
+      },
+    }],
+    ["OS=='mac'", {
+      'xcode_settings': {
+        'CLANG_CXX_LIBRARY': 'libc++',
+        'MACOSX_DEPLOYMENT_TARGET': '10.7',
+        'GCC_ENABLE_CPP_EXCEPTIONS': 'NO',
+      },
+    }],
+  ],
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/nothing.c b/server/node_modules/sqlite3/node_modules/node-addon-api/nothing.c
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/package-support.json b/server/node_modules/sqlite3/node_modules/node-addon-api/package-support.json
new file mode 100644
index 0000000..10d3607
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/package-support.json
@@ -0,0 +1,21 @@
+{
+  "versions": [
+    {
+      "version": "*",
+      "target": {
+        "node": "active"
+      },
+      "response": {
+        "type": "time-permitting",
+        "paid": false,
+        "contact": {
+          "name": "node-addon-api team",
+          "url": "https://github.com/nodejs/node-addon-api/issues"
+        }
+      },
+      "backing": [ { "project": "https://github.com/nodejs" },
+                   { "foundation": "https://openjsf.org/" }
+      ]
+    }
+  ]
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/package.json b/server/node_modules/sqlite3/node_modules/node-addon-api/package.json
new file mode 100644
index 0000000..d772ddc
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/package.json
@@ -0,0 +1,480 @@
+{
+  "bugs": {
+    "url": "https://github.com/nodejs/node-addon-api/issues"
+  },
+  "contributors": [
+    {
+      "name": "Abhishek Kumar Singh",
+      "url": "https://github.com/abhi11210646"
+    },
+    {
+      "name": "Alba Mendez",
+      "url": "https://github.com/jmendeth"
+    },
+    {
+      "name": "Alexander Floh",
+      "url": "https://github.com/alexanderfloh"
+    },
+    {
+      "name": "Ammar Faizi",
+      "url": "https://github.com/ammarfaizi2"
+    },
+    {
+      "name": "András Timár, Dr",
+      "url": "https://github.com/timarandras"
+    },
+    {
+      "name": "Andrew Petersen",
+      "url": "https://github.com/kirbysayshi"
+    },
+    {
+      "name": "Anisha Rohra",
+      "url": "https://github.com/anisha-rohra"
+    },
+    {
+      "name": "Anna Henningsen",
+      "url": "https://github.com/addaleax"
+    },
+    {
+      "name": "Arnaud Botella",
+      "url": "https://github.com/BotellaA"
+    },
+    {
+      "name": "Arunesh Chandra",
+      "url": "https://github.com/aruneshchandra"
+    },
+    {
+      "name": "Azlan Mukhtar",
+      "url": "https://github.com/azlan"
+    },
+    {
+      "name": "Ben Berman",
+      "url": "https://github.com/rivertam"
+    },
+    {
+      "name": "Benjamin Byholm",
+      "url": "https://github.com/kkoopa"
+    },
+    {
+      "name": "Bill Gallafent",
+      "url": "https://github.com/gallafent"
+    },
+    {
+      "name": "blagoev",
+      "url": "https://github.com/blagoev"
+    },
+    {
+      "name": "Bruce A. MacNaughton",
+      "url": "https://github.com/bmacnaughton"
+    },
+    {
+      "name": "Cory Mickelson",
+      "url": "https://github.com/corymickelson"
+    },
+    {
+      "name": "Daniel Bevenius",
+      "url": "https://github.com/danbev"
+    },
+    {
+      "name": "Dante Calderón",
+      "url": "https://github.com/dantehemerson"
+    },
+    {
+      "name": "Darshan Sen",
+      "url": "https://github.com/RaisinTen"
+    },
+    {
+      "name": "David Halls",
+      "url": "https://github.com/davedoesdev"
+    },
+    {
+      "name": "Deepak Rajamohan",
+      "url": "https://github.com/deepakrkris"
+    },
+    {
+      "name": "Dmitry Ashkadov",
+      "url": "https://github.com/dmitryash"
+    },
+    {
+      "name": "Dongjin Na",
+      "url": "https://github.com/nadongguri"
+    },
+    {
+      "name": "Doni Rubiagatra",
+      "url": "https://github.com/rubiagatra"
+    },
+    {
+      "name": "Eric Bickle",
+      "url": "https://github.com/ebickle"
+    },
+    {
+      "name": "extremeheat",
+      "url": "https://github.com/extremeheat"
+    },
+    {
+      "name": "Feng Yu",
+      "url": "https://github.com/F3n67u"
+    },
+    {
+      "name": "Ferdinand Holzer",
+      "url": "https://github.com/fholzer"
+    },
+    {
+      "name": "Gabriel Schulhof",
+      "url": "https://github.com/gabrielschulhof"
+    },
+    {
+      "name": "Guenter Sandner",
+      "url": "https://github.com/gms1"
+    },
+    {
+      "name": "Gus Caplan",
+      "url": "https://github.com/devsnek"
+    },
+    {
+      "name": "Helio Frota",
+      "url": "https://github.com/helio-frota"
+    },
+    {
+      "name": "Hitesh Kanwathirtha",
+      "url": "https://github.com/digitalinfinity"
+    },
+    {
+      "name": "ikokostya",
+      "url": "https://github.com/ikokostya"
+    },
+    {
+      "name": "Jack Xia",
+      "url": "https://github.com/JckXia"
+    },
+    {
+      "name": "Jake Barnes",
+      "url": "https://github.com/DuBistKomisch"
+    },
+    {
+      "name": "Jake Yoon",
+      "url": "https://github.com/yjaeseok"
+    },
+    {
+      "name": "Jason Ginchereau",
+      "url": "https://github.com/jasongin"
+    },
+    {
+      "name": "Jenny",
+      "url": "https://github.com/egg-bread"
+    },
+    {
+      "name": "Jeroen Janssen",
+      "url": "https://github.com/japj"
+    },
+    {
+      "name": "Jim Schlight",
+      "url": "https://github.com/jschlight"
+    },
+    {
+      "name": "Jinho Bang",
+      "url": "https://github.com/romandev"
+    },
+    {
+      "name": "José Expósito",
+      "url": "https://github.com/JoseExposito"
+    },
+    {
+      "name": "joshgarde",
+      "url": "https://github.com/joshgarde"
+    },
+    {
+      "name": "Julian Mesa",
+      "url": "https://github.com/julianmesa-gitkraken"
+    },
+    {
+      "name": "Kasumi Hanazuki",
+      "url": "https://github.com/hanazuki"
+    },
+    {
+      "name": "Kelvin",
+      "url": "https://github.com/kelvinhammond"
+    },
+    {
+      "name": "Kevin Eady",
+      "url": "https://github.com/KevinEady"
+    },
+    {
+      "name": "Kévin VOYER",
+      "url": "https://github.com/kecsou"
+    },
+    {
+      "name": "kidneysolo",
+      "url": "https://github.com/kidneysolo"
+    },
+    {
+      "name": "Koki Nishihara",
+      "url": "https://github.com/Nishikoh"
+    },
+    {
+      "name": "Konstantin Tarkus",
+      "url": "https://github.com/koistya"
+    },
+    {
+      "name": "Kyle Farnung",
+      "url": "https://github.com/kfarnung"
+    },
+    {
+      "name": "Kyle Kovacs",
+      "url": "https://github.com/nullromo"
+    },
+    {
+      "name": "legendecas",
+      "url": "https://github.com/legendecas"
+    },
+    {
+      "name": "LongYinan",
+      "url": "https://github.com/Brooooooklyn"
+    },
+    {
+      "name": "Lovell Fuller",
+      "url": "https://github.com/lovell"
+    },
+    {
+      "name": "Luciano Martorella",
+      "url": "https://github.com/lmartorella"
+    },
+    {
+      "name": "mastergberry",
+      "url": "https://github.com/mastergberry"
+    },
+    {
+      "name": "Mathias Küsel",
+      "url": "https://github.com/mathiask88"
+    },
+    {
+      "name": "Mathias Stearn",
+      "url": "https://github.com/RedBeard0531"
+    },
+    {
+      "name": "Matteo Collina",
+      "url": "https://github.com/mcollina"
+    },
+    {
+      "name": "Michael Dawson",
+      "url": "https://github.com/mhdawson"
+    },
+    {
+      "name": "Michael Price",
+      "url": "https://github.com/mikepricedev"
+    },
+    {
+      "name": "Michele Campus",
+      "url": "https://github.com/kYroL01"
+    },
+    {
+      "name": "Mikhail Cheshkov",
+      "url": "https://github.com/mcheshkov"
+    },
+    {
+      "name": "nempoBu4",
+      "url": "https://github.com/nempoBu4"
+    },
+    {
+      "name": "Nicola Del Gobbo",
+      "url": "https://github.com/NickNaso"
+    },
+    {
+      "name": "Nick Soggin",
+      "url": "https://github.com/iSkore"
+    },
+    {
+      "name": "Nikolai Vavilov",
+      "url": "https://github.com/seishun"
+    },
+    {
+      "name": "Nurbol Alpysbayev",
+      "url": "https://github.com/anurbol"
+    },
+    {
+      "name": "pacop",
+      "url": "https://github.com/pacop"
+    },
+    {
+      "name": "Peter Šándor",
+      "url": "https://github.com/petersandor"
+    },
+    {
+      "name": "Philipp Renoth",
+      "url": "https://github.com/DaAitch"
+    },
+    {
+      "name": "rgerd",
+      "url": "https://github.com/rgerd"
+    },
+    {
+      "name": "Richard Lau",
+      "url": "https://github.com/richardlau"
+    },
+    {
+      "name": "Rolf Timmermans",
+      "url": "https://github.com/rolftimmermans"
+    },
+    {
+      "name": "Ross Weir",
+      "url": "https://github.com/ross-weir"
+    },
+    {
+      "name": "Ryuichi Okumura",
+      "url": "https://github.com/okuryu"
+    },
+    {
+      "name": "Saint Gabriel",
+      "url": "https://github.com/chineduG"
+    },
+    {
+      "name": "Sampson Gao",
+      "url": "https://github.com/sampsongao"
+    },
+    {
+      "name": "Sam Roberts",
+      "url": "https://github.com/sam-github"
+    },
+    {
+      "name": "strager",
+      "url": "https://github.com/strager"
+    },
+    {
+      "name": "Taylor Woll",
+      "url": "https://github.com/boingoing"
+    },
+    {
+      "name": "Thomas Gentilhomme",
+      "url": "https://github.com/fraxken"
+    },
+    {
+      "name": "Tim Rach",
+      "url": "https://github.com/timrach"
+    },
+    {
+      "name": "Tobias Nießen",
+      "url": "https://github.com/tniessen"
+    },
+    {
+      "name": "todoroff",
+      "url": "https://github.com/todoroff"
+    },
+    {
+      "name": "Toyo Li",
+      "url": "https://github.com/toyobayashi"
+    },
+    {
+      "name": "Tux3",
+      "url": "https://github.com/tux3"
+    },
+    {
+      "name": "Vlad Velmisov",
+      "url": "https://github.com/Velmisov"
+    },
+    {
+      "name": "Vladimir Morozov",
+      "url": "https://github.com/vmoroz"
+
+    },
+    {
+      "name": "WenheLI",
+      "url": "https://github.com/WenheLI"
+    },
+    {
+      "name": "Xuguang Mei",
+      "url": "https://github.com/meixg"
+    },
+    {
+      "name": "Yohei Kishimoto",
+      "url": "https://github.com/morokosi"
+    },
+    {
+      "name": "Yulong Wang",
+      "url": "https://github.com/fs-eire"
+    },
+    {
+      "name": "Ziqiu Zhao",
+      "url": "https://github.com/ZzqiZQute"
+    },
+    {
+      "name": "Feng Yu",
+      "url": "https://github.com/F3n67u"
+    },
+    {
+      "name": "wanlu wang",
+      "url": "https://github.com/wanlu"
+    },
+    {
+      "name": "Caleb Hearon",
+      "url": "https://github.com/chearon"
+    },
+    {
+      "name": "Marx",
+      "url": "https://github.com/MarxJiao"
+    },
+    {
+      "name": "Ömer AKGÜL",
+      "url": "https://github.com/tuhalf"
+    }
+  ],
+  "description": "Node.js API (Node-API)",
+  "devDependencies": {
+    "benchmark": "^2.1.4",
+    "bindings": "^1.5.0",
+    "clang-format": "^1.4.0",
+    "eslint": "^7.32.0",
+    "eslint-config-semistandard": "^16.0.0",
+    "eslint-config-standard": "^16.0.3",
+    "eslint-plugin-import": "^2.24.2",
+    "eslint-plugin-node": "^11.1.0",
+    "eslint-plugin-promise": "^5.1.0",
+    "fs-extra": "^11.1.1",
+    "path": "^0.12.7",
+    "pre-commit": "^1.2.2",
+    "safe-buffer": "^5.1.1"
+  },
+  "directories": {},
+  "gypfile": false,
+  "homepage": "https://github.com/nodejs/node-addon-api",
+  "keywords": [
+    "n-api",
+    "napi",
+    "addon",
+    "native",
+    "bindings",
+    "c",
+    "c++",
+    "nan",
+    "node-addon-api"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "name": "node-addon-api",
+  "readme": "README.md",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/nodejs/node-addon-api.git"
+  },
+  "files": [
+    "*.{c,h,gyp,gypi}",
+    "package-support.json",
+    "tools/"
+  ],
+  "scripts": {
+    "prebenchmark": "node-gyp rebuild -C benchmark",
+    "benchmark": "node benchmark",
+    "pretest": "node-gyp rebuild -C test",
+    "test": "node test",
+    "test:debug": "node-gyp rebuild -C test --debug && NODE_API_BUILD_CONFIG=Debug node ./test/index.js",
+    "predev": "node-gyp rebuild -C test --debug",
+    "dev": "node test",
+    "predev:incremental": "node-gyp configure build -C test --debug",
+    "dev:incremental": "node test",
+    "doc": "doxygen doc/Doxyfile",
+    "lint": "node tools/eslint-format && node tools/clang-format",
+    "lint:fix": "node tools/clang-format --fix && node tools/eslint-format --fix"
+  },
+  "pre-commit": "lint",
+  "version": "7.1.1",
+  "support": true
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/tools/README.md b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/README.md
new file mode 100644
index 0000000..6b80e94
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/README.md
@@ -0,0 +1,73 @@
+# Tools
+
+## clang-format
+
+The clang-format checking tools is designed to check changed lines of code compared to given git-refs.
+
+## Migration Script
+
+The migration tool is designed to reduce repetitive work in the migration process. However, the script is not aiming to convert every thing for you. There are usually some small fixes and major reconstruction required.
+
+### How To Use
+
+To run the conversion script, first make sure you have the latest `node-addon-api` in your `node_modules` directory.
+```
+npm install node-addon-api
+```
+
+Then run the script passing your project directory
+```
+node ./node_modules/node-addon-api/tools/conversion.js ./
+```
+
+After finish, recompile and debug things that are missed by the script.
+
+
+### Quick Fixes
+Here is the list of things that can be fixed easily.
+  1. Change your methods' return value to void if it doesn't return value to JavaScript.
+  2. Use `.` to access attribute or to invoke member function in Napi::Object instead of `->`.
+  3. `Napi::New(env, value);` to `Napi::[Type]::New(env, value);
+
+
+### Major Reconstructions
+The implementation of `Napi::ObjectWrap` is significantly different from NAN's. `Napi::ObjectWrap` takes a pointer to the wrapped object and creates a reference to the wrapped object inside ObjectWrap constructor. `Napi::ObjectWrap` also associates wrapped object's instance methods to Javascript module instead of static methods like NAN.
+
+So if you use Nan::ObjectWrap in your module, you will need to execute the following steps.
+
+  1. Convert your [ClassName]::New function to a constructor function that takes a `Napi::CallbackInfo`. Declare it as
+```
+[ClassName](const Napi::CallbackInfo& info);
+```
+and define it as
+```
+[ClassName]::[ClassName](const Napi::CallbackInfo& info) : Napi::ObjectWrap<[ClassName]>(info){
+  ...
+}
+```
+This way, the `Napi::ObjectWrap` constructor will be invoked after the object has been instantiated and `Napi::ObjectWrap` can use the `this` pointer to create a reference to the wrapped object.
+
+  2. Move your original constructor code into the new constructor. Delete your original constructor.
+  3. In your class initialization function, associate native methods in the following way.
+```
+Napi::FunctionReference constructor;
+
+void [ClassName]::Init(Napi::Env env, Napi::Object exports, Napi::Object module) {
+  Napi::HandleScope scope(env);
+  Napi::Function ctor = DefineClass(env, "Canvas", {
+    InstanceMethod<&[ClassName]::Func1>("Func1"),
+    InstanceMethod<&[ClassName]::Func2>("Func2"),
+    InstanceAccessor<&[ClassName]::ValueGetter>("Value"),
+    StaticMethod<&[ClassName]::StaticMethod>("MethodName"),
+    InstanceValue("Value", Napi::[Type]::New(env, value)),
+  });
+
+  constructor = Napi::Persistent(ctor);
+  constructor .SuppressDestruct();
+  exports.Set("[ClassName]", ctor);
+}
+```
+  4. In function where you need to Unwrap the ObjectWrap in NAN like `[ClassName]* native = Nan::ObjectWrap::Unwrap<[ClassName]>(info.This());`, use `this` pointer directly as the unwrapped object as each ObjectWrap instance is associated with a unique object instance.
+
+
+If you still find issues after following this guide, please leave us an issue describing your problem and we will try to resolve it.
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/tools/check-napi.js b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/check-napi.js
new file mode 100644
index 0000000..9199af3
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/check-napi.js
@@ -0,0 +1,99 @@
+'use strict';
+// Descend into a directory structure and, for each file matching *.node, output
+// based on the imports found in the file whether it's an N-API module or not.
+
+const fs = require('fs');
+const path = require('path');
+
+// Read the output of the command, break it into lines, and use the reducer to
+// decide whether the file is an N-API module or not.
+function checkFile (file, command, argv, reducer) {
+  const child = require('child_process').spawn(command, argv, {
+    stdio: ['inherit', 'pipe', 'inherit']
+  });
+  let leftover = '';
+  let isNapi;
+  child.stdout.on('data', (chunk) => {
+    if (isNapi === undefined) {
+      chunk = (leftover + chunk.toString()).split(/[\r\n]+/);
+      leftover = chunk.pop();
+      isNapi = chunk.reduce(reducer, isNapi);
+      if (isNapi !== undefined) {
+        child.kill();
+      }
+    }
+  });
+  child.on('close', (code, signal) => {
+    if ((code === null && signal !== null) || (code !== 0)) {
+      console.log(
+        command + ' exited with code: ' + code + ' and signal: ' + signal);
+    } else {
+      // Green if it's a N-API module, red otherwise.
+      console.log(
+        '\x1b[' + (isNapi ? '42' : '41') + 'm' +
+          (isNapi ? '    N-API' : 'Not N-API') +
+          '\x1b[0m: ' + file);
+    }
+  });
+}
+
+// Use nm -a to list symbols.
+function checkFileUNIX (file) {
+  checkFile(file, 'nm', ['-a', file], (soFar, line) => {
+    if (soFar === undefined) {
+      line = line.match(/([0-9a-f]*)? ([a-zA-Z]) (.*$)/);
+      if (line[2] === 'U') {
+        if (/^napi/.test(line[3])) {
+          soFar = true;
+        }
+      }
+    }
+    return soFar;
+  });
+}
+
+// Use dumpbin /imports to list symbols.
+function checkFileWin32 (file) {
+  checkFile(file, 'dumpbin', ['/imports', file], (soFar, line) => {
+    if (soFar === undefined) {
+      line = line.match(/([0-9a-f]*)? +([a-zA-Z0-9]) (.*$)/);
+      if (line && /^napi/.test(line[line.length - 1])) {
+        soFar = true;
+      }
+    }
+    return soFar;
+  });
+}
+
+// Descend into a directory structure and pass each file ending in '.node' to
+// one of the above checks, depending on the OS.
+function recurse (top) {
+  fs.readdir(top, (error, items) => {
+    if (error) {
+      throw new Error('error reading directory ' + top + ': ' + error);
+    }
+    items.forEach((item) => {
+      item = path.join(top, item);
+      fs.stat(item, ((item) => (error, stats) => {
+        if (error) {
+          throw new Error('error about ' + item + ': ' + error);
+        }
+        if (stats.isDirectory()) {
+          recurse(item);
+        } else if (/[.]node$/.test(item) &&
+            // Explicitly ignore files called 'nothing.node' because they are
+            // artefacts of node-addon-api having identified a version of
+            // Node.js that ships with a correct implementation of N-API.
+            path.basename(item) !== 'nothing.node') {
+          process.platform === 'win32'
+            ? checkFileWin32(item)
+            : checkFileUNIX(item);
+        }
+      })(item));
+    });
+  });
+}
+
+// Start with the directory given on the command line or the current directory
+// if nothing was given.
+recurse(process.argv.length > 3 ? process.argv[2] : '.');
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/tools/clang-format.js b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/clang-format.js
new file mode 100644
index 0000000..e4bb4f5
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/clang-format.js
@@ -0,0 +1,71 @@
+#!/usr/bin/env node
+
+const spawn = require('child_process').spawnSync;
+const path = require('path');
+
+const filesToCheck = ['*.h', '*.cc'];
+const FORMAT_START = process.env.FORMAT_START || 'main';
+
+function main (args) {
+  let fix = false;
+  while (args.length > 0) {
+    switch (args[0]) {
+      case '-f':
+      case '--fix':
+        fix = true;
+        break;
+      default:
+    }
+    args.shift();
+  }
+
+  const clangFormatPath = path.dirname(require.resolve('clang-format'));
+  const binary = process.platform === 'win32'
+    ? 'node_modules\\.bin\\clang-format.cmd'
+    : 'node_modules/.bin/clang-format';
+  const options = ['--binary=' + binary, '--style=file'];
+  if (fix) {
+    options.push(FORMAT_START);
+  } else {
+    options.push('--diff', FORMAT_START);
+  }
+
+  const gitClangFormatPath = path.join(clangFormatPath, 'bin/git-clang-format');
+  const result = spawn(
+    'python',
+    [gitClangFormatPath, ...options, '--', ...filesToCheck],
+    { encoding: 'utf-8' }
+  );
+
+  if (result.stderr) {
+    console.error('Error running git-clang-format:', result.stderr);
+    return 2;
+  }
+
+  const clangFormatOutput = result.stdout.trim();
+  // Bail fast if in fix mode.
+  if (fix) {
+    console.log(clangFormatOutput);
+    return 0;
+  }
+  // Detect if there is any complains from clang-format
+  if (
+    clangFormatOutput !== '' &&
+    clangFormatOutput !== 'no modified files to format' &&
+    clangFormatOutput !== 'clang-format did not modify any files'
+  ) {
+    console.error(clangFormatOutput);
+    const fixCmd = 'npm run lint:fix';
+    console.error(`
+      ERROR: please run "${fixCmd}" to format changes in your commit
+        Note that when running the command locally, please keep your local
+        main branch and working branch up to date with nodejs/node-addon-api
+        to exclude un-related complains.
+        Or you can run "env FORMAT_START=upstream/main ${fixCmd}".`);
+    return 1;
+  }
+}
+
+if (require.main === module) {
+  process.exitCode = main(process.argv.slice(2));
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/tools/conversion.js b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/conversion.js
new file mode 100755
index 0000000..f89245a
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/conversion.js
@@ -0,0 +1,301 @@
+#! /usr/bin/env node
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+const args = process.argv.slice(2);
+const dir = args[0];
+if (!dir) {
+  console.log('Usage: node ' + path.basename(__filename) + ' <target-dir>');
+  process.exit(1);
+}
+
+const NodeApiVersion = require('../package.json').version;
+
+const disable = args[1];
+let ConfigFileOperations;
+if (disable !== '--disable' && dir !== '--disable') {
+  ConfigFileOperations = {
+    'package.json': [
+      [/([ ]*)"dependencies": {/g, '$1"dependencies": {\n$1  "node-addon-api": "' + NodeApiVersion + '",'],
+      [/[ ]*"nan": *"[^"]+"(,|)[\n\r]/g, '']
+    ],
+    'binding.gyp': [
+      [/([ ]*)'include_dirs': \[/g, '$1\'include_dirs\': [\n$1  \'<!(node -p "require(\\\'node-addon-api\\\').include_dir")\','],
+      [/([ ]*)"include_dirs": \[/g, '$1"include_dirs": [\n$1  "<!(node -p \\"require(\'node-addon-api\').include_dir\\")",'],
+      [/[ ]*("|')<!$node -e ("|'|\\"|\\')require\(("|'|\\"|\\')nan("|'|\\"|\\')$("|'|\\"|\\')\)("|')(,|)[\r\n]/g, ''],
+      [/([ ]*)("|')target_name("|'): ("|')(.+?)("|'),/g, '$1$2target_name$2: $4$5$6,\n      $2cflags!$2: [ $2-fno-exceptions$2 ],\n      $2cflags_cc!$2: [ $2-fno-exceptions$2 ],\n      $2xcode_settings$2: { $2GCC_ENABLE_CPP_EXCEPTIONS$2: $2YES$2,\n        $2CLANG_CXX_LIBRARY$2: $2libc++$2,\n        $2MACOSX_DEPLOYMENT_TARGET$2: $210.7$2,\n      },\n      $2msvs_settings$2: {\n        $2VCCLCompilerTool$2: { $2ExceptionHandling$2: 1 },\n      },']
+    ]
+  };
+} else {
+  ConfigFileOperations = {
+    'package.json': [
+      [/([ ]*)"dependencies": {/g, '$1"dependencies": {\n$1  "node-addon-api": "' + NodeApiVersion + '",'],
+      [/[ ]*"nan": *"[^"]+"(,|)[\n\r]/g, '']
+    ],
+    'binding.gyp': [
+      [/([ ]*)'include_dirs': \[/g, '$1\'include_dirs\': [\n$1  \'<!(node -p "require(\\\'node-addon-api\\\').include_dir")\','],
+      [/([ ]*)"include_dirs": \[/g, '$1"include_dirs": [\n$1  "<!(node -p \'require(\\"node-addon-api\\").include_dir\')",'],
+      [/[ ]*("|')<!$node -e ("|'|\\"|\\')require\(("|'|\\"|\\')nan("|'|\\"|\\')$("|'|\\"|\\')\)("|')(,|)[\r\n]/g, ''],
+      [/([ ]*)("|')target_name("|'): ("|')(.+?)("|'),/g, '$1$2target_name$2: $4$5$6,\n      $2cflags!$2: [ $2-fno-exceptions$2 ],\n      $2cflags_cc!$2: [ $2-fno-exceptions$2 ],\n      $2defines$2: [ $2NAPI_DISABLE_CPP_EXCEPTIONS$2 ],\n      $2conditions$2: [\n        [\'OS=="win"\', { $2defines$2: [ $2_HAS_EXCEPTIONS=1$2 ] }]\n      ]']
+    ]
+  };
+}
+
+const SourceFileOperations = [
+  [/Nan::SetMethod$target,[\s]*"(.*)"[\s]*,[\s]*([^)]+)$/g, 'exports.Set(Napi::String::New(env, "$1"), Napi::Function::New(env, $2))'],
+
+  [/v8::Local<v8::FunctionTemplate>\s+(\w+)\s*=\s*Nan::New<FunctionTemplate>$[\w\d:]+$;(?:\w+->Reset$\1$)?\s+\1->SetClassName$Nan::String::New\("(\w+)"$\);/g, 'Napi::Function $1 = DefineClass(env, "$2", {'],
+  [/Local<FunctionTemplate>\s+(\w+)\s*=\s*Nan::New<FunctionTemplate>$[\w\d:]+$;\s+(\w+)\.Reset$(\1)$;\s+\1->SetClassName$(Nan::String::New|Nan::New<(v8::)*String>)\("(.+?)"$\);/g, 'Napi::Function $1 = DefineClass(env, "$6", {'],
+  [/Local<FunctionTemplate>\s+(\w+)\s*=\s*Nan::New<FunctionTemplate>$[\w\d:]+$;(?:\w+->Reset$\1$)?\s+\1->SetClassName$Nan::String::New\("(\w+)"$\);/g, 'Napi::Function $1 = DefineClass(env, "$2", {'],
+  [/Nan::New<v8::FunctionTemplate>$([\w\d:]+)$->GetFunction/g, 'Napi::Function::New(env, $1)'],
+  [/Nan::New<FunctionTemplate>$([\w\d:]+)$->GetFunction()/g, 'Napi::Function::New(env, $1);'],
+  [/Nan::New<v8::FunctionTemplate>$([\w\d:]+)$/g, 'Napi::Function::New(env, $1)'],
+  [/Nan::New<FunctionTemplate>$([\w\d:]+)$/g, 'Napi::Function::New(env, $1)'],
+
+  // FunctionTemplate to FunctionReference
+  [/Nan::Persistent<(v8::)*FunctionTemplate>/g, 'Napi::FunctionReference'],
+  [/Nan::Persistent<(v8::)*Function>/g, 'Napi::FunctionReference'],
+  [/v8::Local<v8::FunctionTemplate>/g, 'Napi::FunctionReference'],
+  [/Local<FunctionTemplate>/g, 'Napi::FunctionReference'],
+  [/v8::FunctionTemplate/g, 'Napi::FunctionReference'],
+  [/FunctionTemplate/g, 'Napi::FunctionReference'],
+
+  [/([ ]*)Nan::SetPrototypeMethod$\w+, "(\w+)", (\w+)$;/g, '$1InstanceMethod("$2", &$3),'],
+  [/([ ]*)(?:\w+\.Reset$\w+$;\s+)?$target$\.Set$"(\w+)",\s*Nan::GetFunction\((\w+)$\);/gm,
+    '});\n\n' +
+    '$1constructor = Napi::Persistent($3);\n' +
+    '$1constructor.SuppressDestruct();\n' +
+    '$1target.Set("$2", $3);'],
+
+  // TODO: Other attribute combinations
+  [/static_cast<PropertyAttribute>$ReadOnly\s*\|\s*DontDelete$/gm,
+    'static_cast<napi_property_attributes>(napi_enumerable | napi_configurable)'],
+
+  [/([\w\d:<>]+?)::Cast$(.+?)$/g, '$2.As<$1>()'],
+
+  [/\*Nan::Utf8String$([^)]+)$/g, '$1->As<Napi::String>().Utf8Value().c_str()'],
+  [/Nan::Utf8String +(\w+)$([^)]+)$/g, 'std::string $1 = $2.As<Napi::String>()'],
+  [/Nan::Utf8String/g, 'std::string'],
+
+  [/v8::String::Utf8Value (.+?)$(.+?)$/g, 'Napi::String $1(env, $2)'],
+  [/String::Utf8Value (.+?)$(.+?)$/g, 'Napi::String $1(env, $2)'],
+  [/\.length/g, '.Length()'],
+
+  [/Nan::MakeCallback$([^,]+),[\s\\]+([^,]+),/gm, '$2.MakeCallback($1,'],
+
+  [/class\s+(\w+)\s*:\s*public\s+Nan::ObjectWrap/g, 'class $1 : public Napi::ObjectWrap<$1>'],
+  [/(\w+)\(([^)]*)$\s*:\s*Nan::ObjectWrap\s*(,)?/gm, '$1($2) : Napi::ObjectWrap<$1>()$3'],
+
+  // HandleOKCallback to OnOK
+  [/HandleOKCallback/g, 'OnOK'],
+  // HandleErrorCallback to OnError
+  [/HandleErrorCallback/g, 'OnError'],
+
+  // ex. .As<Function>() to .As<Napi::Object>()
+  [/\.As<v8::(Value|Boolean|String|Number|Object|Array|Symbol|External|Function)>/g, '.As<Napi::$1>()'],
+  [/\.As<(Value|Boolean|String|Number|Object|Array|Symbol|External|Function)>/g, '.As<Napi::$1>()'],
+
+  // ex. Nan::New<Number>(info[0]) to Napi::Number::New(info[0])
+  [/Nan::New<(v8::)*Integer>$(.+?)$/g, 'Napi::Number::New(env, $2)'],
+  [/Nan::New$([0-9.]+)$/g, 'Napi::Number::New(env, $1)'],
+  [/Nan::New<(v8::)*String>$"(.+?)"$/g, 'Napi::String::New(env, "$2")'],
+  [/Nan::New$"(.+?)"$/g, 'Napi::String::New(env, "$1")'],
+  [/Nan::New<(v8::)*(.+?)>/g, 'Napi::$2::New(env)'],
+  [/Nan::New<(.+?)>/g, 'Napi::$1::New(env)'],
+  [/Nan::New<(v8::)*(.+?)>$/g, 'Napi::$2::New(env, '],
+  [/Nan::New<(.+?)>\(/g, 'Napi::$1::New(env, '],
+  [/Nan::NewBuffer\(/g, 'Napi::Buffer<char>::New(env, '],
+  // TODO: Properly handle this
+  [/Nan::New\(/g, 'Napi::New(env, '],
+
+  [/\.IsInt32\($/g, '.IsNumber()'],
+  [/->IsInt32/g, '.IsNumber()'],
+
+  [/(.+?)->BooleanValue/g, '$1.As<Napi::Boolean>().Value()'],
+  [/(.+?)->Int32Value/g, '$1.As<Napi::Number>().Int32Value()'],
+  [/(.+?)->Uint32Value/g, '$1.As<Napi::Number>().Uint32Value()'],
+  [/(.+?)->IntegerValue/g, '$1.As<Napi::Number>().Int64Value()'],
+  [/(.+?)->NumberValue/g, '$1.As<Napi::Number>().DoubleValue()'],
+
+  // ex. Nan::To<bool>(info[0]) to info[0].Value()
+  [/Nan::To<v8::(Boolean|String|Number|Object|Array|Symbol|Function)>$(.+?)$/g, '$2.To<Napi::$1>()'],
+  [/Nan::To<(Boolean|String|Number|Object|Array|Symbol|Function)>$(.+?)$/g, '$2.To<Napi::$1>()'],
+  // ex. Nan::To<bool>(info[0]) to info[0].As<Napi::Boolean>().Value()
+  [/Nan::To<bool>$(.+?)$/g, '$1.As<Napi::Boolean>().Value()'],
+  // ex. Nan::To<int>(info[0]) to info[0].As<Napi::Number>().Int32Value()
+  [/Nan::To<int>$(.+?)$/g, '$1.As<Napi::Number>().Int32Value()'],
+  // ex. Nan::To<int32_t>(info[0]) to info[0].As<Napi::Number>().Int32Value()
+  [/Nan::To<int32_t>$(.+?)$/g, '$1.As<Napi::Number>().Int32Value()'],
+  // ex. Nan::To<uint32_t>(info[0]) to info[0].As<Napi::Number>().Uint32Value()
+  [/Nan::To<uint32_t>$(.+?)$/g, '$1.As<Napi::Number>().Uint32Value()'],
+  // ex. Nan::To<int64_t>(info[0]) to info[0].As<Napi::Number>().Int64Value()
+  [/Nan::To<int64_t>$(.+?)$/g, '$1.As<Napi::Number>().Int64Value()'],
+  // ex. Nan::To<float>(info[0]) to info[0].As<Napi::Number>().FloatValue()
+  [/Nan::To<float>$(.+?)$/g, '$1.As<Napi::Number>().FloatValue()'],
+  // ex. Nan::To<double>(info[0]) to info[0].As<Napi::Number>().DoubleValue()
+  [/Nan::To<double>$(.+?)$/g, '$1.As<Napi::Number>().DoubleValue()'],
+
+  [/Nan::New$(\w+)$->HasInstance$(\w+)$/g, '$2.InstanceOf($1.Value())'],
+
+  [/Nan::Has$([^,]+),\s*/gm, '($1).Has('],
+  [/\.Has\([\s|\\]*Nan::New<(v8::)*String>\(([^)]+)$\)/gm, '.Has($1)'],
+  [/\.Has$[\s|\\]*Nan::New\(([^)]+)$\)/gm, '.Has($1)'],
+
+  [/Nan::Get$([^,]+),\s*/gm, '($1).Get('],
+  [/\.Get\([\s|\\]*Nan::New<(v8::)*String>\(([^)]+)$\)/gm, '.Get($1)'],
+  [/\.Get$[\s|\\]*Nan::New\(([^)]+)$\)/gm, '.Get($1)'],
+
+  [/Nan::Set$([^,]+),\s*/gm, '($1).Set('],
+  [/\.Set\([\s|\\]*Nan::New<(v8::)*String>\(([^)]+)$\s*,/gm, '.Set($1,'],
+  [/\.Set$[\s|\\]*Nan::New\(([^)]+)$\s*,/gm, '.Set($1,'],
+
+  // ex. node::Buffer::HasInstance(info[0]) to info[0].IsBuffer()
+  [/node::Buffer::HasInstance$(.+?)$/g, '$1.IsBuffer()'],
+  // ex. node::Buffer::Length(info[0]) to info[0].Length()
+  [/node::Buffer::Length$(.+?)$/g, '$1.As<Napi::Buffer<char>>().Length()'],
+  // ex. node::Buffer::Data(info[0]) to info[0].Data()
+  [/node::Buffer::Data$(.+?)$/g, '$1.As<Napi::Buffer<char>>().Data()'],
+  [/Nan::CopyBuffer$/g, 'Napi::Buffer::Copy(env, '],
+
+  // Nan::AsyncQueueWorker(worker)
+  [/Nan::AsyncQueueWorker\((.+)$;/g, '$1.Queue();'],
+  [/Nan::(Undefined|Null|True|False)/g, 'env.$1()'],
+
+  // Nan::ThrowError(error) to Napi::Error::New(env, error).ThrowAsJavaScriptException()
+  [/([ ]*)return Nan::Throw(\w*?)Error$(.+?)$;/g, '$1Napi::$2Error::New(env, $3).ThrowAsJavaScriptException();\n$1return env.Null();'],
+  [/Nan::Throw(\w*?)Error$(.+?)$;\n(\s*)return;/g, 'Napi::$1Error::New(env, $2).ThrowAsJavaScriptException();\n$3return env.Null();'],
+  [/Nan::Throw(\w*?)Error$(.+?)$;/g, 'Napi::$1Error::New(env, $2).ThrowAsJavaScriptException();\n'],
+  // Nan::RangeError(error) to Napi::RangeError::New(env, error)
+  [/Nan::(\w*?)Error$(.+)$/g, 'Napi::$1Error::New(env, $2)'],
+
+  [/Nan::Set$(.+?),\n* *(.+?),\n* *(.+?),\n* *(.+?)$/g, '$1.Set($2, $3, $4)'],
+
+  [/Nan::(Escapable)?HandleScope\s+(\w+)\s*;/g, 'Napi::$1HandleScope $2(env);'],
+  [/Nan::(Escapable)?HandleScope/g, 'Napi::$1HandleScope'],
+  [/Nan::ForceSet$([^,]+), ?/g, '$1->DefineProperty('],
+  [/\.ForceSet\(Napi::String::New\(env, "(\w+)"$,\s*?/g, '.DefineProperty("$1", '],
+  // [ /Nan::GetPropertyNames$([^,]+)$/, '$1->GetPropertyNames()' ],
+  [/Nan::Equals$([^,]+),/g, '$1.StrictEquals('],
+
+  [/(.+)->Set\(/g, '$1.Set('],
+
+  [/Nan::Callback/g, 'Napi::FunctionReference'],
+
+  [/Nan::Persistent<Object>/g, 'Napi::ObjectReference'],
+  [/Nan::ADDON_REGISTER_FUNCTION_ARGS_TYPE target/g, 'Napi::Env& env, Napi::Object& target'],
+
+  [/(\w+)\*\s+(\w+)\s*=\s*Nan::ObjectWrap::Unwrap<\w+>\(info\.This\($\);/g, '$1* $2 = this;'],
+  [/Nan::ObjectWrap::Unwrap<(\w+)>$(.*)$;/g, '$2.Unwrap<$1>();'],
+
+  [/Nan::NAN_METHOD_RETURN_TYPE/g, 'void'],
+  [/NAN_INLINE/g, 'inline'],
+
+  [/Nan::NAN_METHOD_ARGS_TYPE/g, 'const Napi::CallbackInfo&'],
+  [/NAN_METHOD$([\w\d:]+?)$/g, 'Napi::Value $1(const Napi::CallbackInfo& info)'],
+  [/static\s*NAN_GETTER$([\w\d:]+?)$/g, 'Napi::Value $1(const Napi::CallbackInfo& info)'],
+  [/NAN_GETTER$([\w\d:]+?)$/g, 'Napi::Value $1(const Napi::CallbackInfo& info)'],
+  [/static\s*NAN_SETTER$([\w\d:]+?)$/g, 'void $1(const Napi::CallbackInfo& info, const Napi::Value& value)'],
+  [/NAN_SETTER$([\w\d:]+?)$/g, 'void $1(const Napi::CallbackInfo& info, const Napi::Value& value)'],
+  [/void Init$(v8::)*Local<(v8::)*Object> exports$/g, 'Napi::Object Init(Napi::Env env, Napi::Object exports)'],
+  [/NAN_MODULE_INIT$([\w\d:]+?)$;/g, 'Napi::Object $1(Napi::Env env, Napi::Object exports);'],
+  [/NAN_MODULE_INIT$([\w\d:]+?)$/g, 'Napi::Object $1(Napi::Env env, Napi::Object exports)'],
+
+  [/::(Init(?:ialize)?)$target$/g, '::$1(env, target, module)'],
+  [/constructor_template/g, 'constructor'],
+
+  [/Nan::FunctionCallbackInfo<(v8::)?Value>[ ]*& [ ]*info\)[ ]*{\n*([ ]*)/gm, 'Napi::CallbackInfo& info) {\n$2Napi::Env env = info.Env();\n$2'],
+  [/Nan::FunctionCallbackInfo<(v8::)*Value>\s*&\s*info\);/g, 'Napi::CallbackInfo& info);'],
+  [/Nan::FunctionCallbackInfo<(v8::)*Value>\s*&/g, 'Napi::CallbackInfo&'],
+
+  [/Buffer::HasInstance$([^)]+)$/g, '$1.IsBuffer()'],
+
+  [/info\[(\d+)\]->/g, 'info[$1].'],
+  [/info\[([\w\d]+)\]->/g, 'info[$1].'],
+  [/info\.This->/g, 'info.This().'],
+  [/->Is(Object|String|Int32|Number)/g, '.Is$1()'],
+  [/info.GetReturnValue.SetUndefined/g, 'return env.Undefined()'],
+  [/info\.GetReturnValue\.Set$((\n|.)+?)$;/g, 'return $1;'],
+
+  // ex. Local<Value> to Napi::Value
+  [/v8::Local<v8::(Value|Boolean|String|Number|Object|Array|Symbol|External|Function)>/g, 'Napi::$1'],
+  [/Local<(Value|Boolean|String|Number|Object|Array|Symbol|External|Function)>/g, 'Napi::$1'],
+
+  // Declare an env in helper functions that take a Napi::Value
+  [/(\w+)$Napi::Value (\w+)(,\s*[^()]+)?$\s*{\n*([ ]*)/gm, '$1(Napi::Value $2$3) {\n$4Napi::Env env = $2.Env();\n$4'],
+
+  // delete #include <node.h> and/or <v8.h>
+  [/#include +(<|")(?:node|nan).h("|>)/g, '#include $1napi.h$2\n#include $1uv.h$2'],
+  // NODE_MODULE to NODE_API_MODULE
+  [/NODE_MODULE/g, 'NODE_API_MODULE'],
+  [/Nan::/g, 'Napi::'],
+  [/nan.h/g, 'napi.h'],
+
+  // delete .FromJust()
+  [/\.FromJust/g, ''],
+  // delete .ToLocalCheck()
+  [/\.ToLocalChecked/g, ''],
+  [/^.*->SetInternalFieldCount\(.*$/gm, ''],
+
+  // replace using node; and/or using v8; to using Napi;
+  [/using (node|v8);/g, 'using Napi;'],
+  [/using namespace (node|Nan|v8);/g, 'using namespace Napi;'],
+  // delete using v8::Local;
+  [/using v8::Local;\n/g, ''],
+  // replace using v8::XXX; with using Napi::XXX
+  [/using v8::([A-Za-z]+);/g, 'using Napi::$1;']
+
+];
+
+const paths = listFiles(dir);
+paths.forEach(function (dirEntry) {
+  const filename = dirEntry.split('\\').pop().split('/').pop();
+
+  // Check whether the file is a source file or a config file
+  // then execute function accordingly
+  const sourcePattern = /.+\.h|.+\.cc|.+\.cpp/;
+  if (sourcePattern.test(filename)) {
+    convertFile(dirEntry, SourceFileOperations);
+  } else if (ConfigFileOperations[filename] != null) {
+    convertFile(dirEntry, ConfigFileOperations[filename]);
+  }
+});
+
+function listFiles (dir, filelist) {
+  const files = fs.readdirSync(dir);
+  filelist = filelist || [];
+  files.forEach(function (file) {
+    if (file === 'node_modules') {
+      return;
+    }
+
+    if (fs.statSync(path.join(dir, file)).isDirectory()) {
+      filelist = listFiles(path.join(dir, file), filelist);
+    } else {
+      filelist.push(path.join(dir, file));
+    }
+  });
+  return filelist;
+}
+
+function convert (content, operations) {
+  for (let i = 0; i < operations.length; i++) {
+    const operation = operations[i];
+    content = content.replace(operation[0], operation[1]);
+  }
+  return content;
+}
+
+function convertFile (fileName, operations) {
+  fs.readFile(fileName, 'utf-8', function (err, file) {
+    if (err) throw err;
+
+    file = convert(file, operations);
+
+    fs.writeFile(fileName, file, function (err) {
+      if (err) throw err;
+    });
+  });
+}
diff --git a/server/node_modules/sqlite3/node_modules/node-addon-api/tools/eslint-format.js b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/eslint-format.js
new file mode 100644
index 0000000..6923ab7
--- /dev/null
+++ b/server/node_modules/sqlite3/node_modules/node-addon-api/tools/eslint-format.js
@@ -0,0 +1,79 @@
+#!/usr/bin/env node
+
+const spawn = require('child_process').spawnSync;
+
+const filesToCheck = '*.js';
+const FORMAT_START = process.env.FORMAT_START || 'main';
+const IS_WIN = process.platform === 'win32';
+const ESLINT_PATH = IS_WIN ? 'node_modules\\.bin\\eslint.cmd' : 'node_modules/.bin/eslint';
+
+function main (args) {
+  let fix = false;
+  while (args.length > 0) {
+    switch (args[0]) {
+      case '-f':
+      case '--fix':
+        fix = true;
+        break;
+      default:
+    }
+    args.shift();
+  }
+
+  // Check js files that change on unstaged file
+  const fileUnStaged = spawn(
+    'git',
+    ['diff', '--name-only', '--diff-filter=d', FORMAT_START, filesToCheck],
+    {
+      encoding: 'utf-8'
+    }
+  );
+
+  // Check js files that change on staged file
+  const fileStaged = spawn(
+    'git',
+    ['diff', '--name-only', '--cached', '--diff-filter=d', FORMAT_START, filesToCheck],
+    {
+      encoding: 'utf-8'
+    }
+  );
+
+  const options = [
+    ...fileStaged.stdout.split('\n').filter((f) => f !== ''),
+    ...fileUnStaged.stdout.split('\n').filter((f) => f !== '')
+  ];
+
+  if (fix) {
+    options.push('--fix');
+  }
+
+  const result = spawn(ESLINT_PATH, [...options], {
+    encoding: 'utf-8'
+  });
+
+  if (result.error && result.error.errno === 'ENOENT') {
+    console.error('Eslint not found! Eslint is supposed to be found at ', ESLINT_PATH);
+    return 2;
+  }
+
+  if (result.status === 1) {
+    console.error('Eslint error:', result.stdout);
+    const fixCmd = 'npm run lint:fix';
+    console.error(`ERROR: please run "${fixCmd}" to format changes in your commit
+    Note that when running the command locally, please keep your local
+    main branch and working branch up to date with nodejs/node-addon-api
+    to exclude un-related complains.
+    Or you can run "env FORMAT_START=upstream/main ${fixCmd}".
+    Also fix JS files by yourself if necessary.`);
+    return 1;
+  }
+
+  if (result.stderr) {
+    console.error('Error running eslint:', result.stderr);
+    return 2;
+  }
+}
+
+if (require.main === module) {
+  process.exitCode = main(process.argv.slice(2));
+}
diff --git a/server/node_modules/sqlite3/package.json b/server/node_modules/sqlite3/package.json
new file mode 100644
index 0000000..ab413ff
--- /dev/null
+++ b/server/node_modules/sqlite3/package.json
@@ -0,0 +1,89 @@
+{
+  "name": "sqlite3",
+  "description": "Asynchronous, non-blocking SQLite3 bindings",
+  "version": "5.1.7",
+  "homepage": "https://github.com/TryGhost/node-sqlite3",
+  "author": {
+    "name": "Mapbox",
+    "url": "https://mapbox.com/"
+  },
+  "binary": {
+    "napi_versions": [
+      3,
+      6
+    ]
+  },
+  "contributors": [
+    "Daniel Lockyer <hi@daniellockyer.com>",
+    "Konstantin Käfer <mail@kkaefer.com>",
+    "Dane Springmeyer <dane@mapbox.com>",
+    "Will White <will@mapbox.com>",
+    "Orlando Vazquez <ovazquez@gmail.com>",
+    "Artem Kustikov <kustikoff@gmail.com>",
+    "Eric Fredricksen <efredricksen@gmail.com>",
+    "John Wright <mrjjwright@gmail.com>",
+    "Ryan Dahl <ry@tinyclouds.org>",
+    "Tom MacWright <tom@mapbox.com>",
+    "Carter Thaxton <carter.thaxton@gmail.com>",
+    "Audrius Kažukauskas <audrius@neutrino.lt>",
+    "Johannes Schauer <josch@pyneo.org>",
+    "Nathan Rajlich <nathan@tootallnate.net>",
+    "AJ ONeal <coolaj86@gmail.com>",
+    "Mithgol",
+    "Ben Noordhuis <ben@strongloop.com>"
+  ],
+  "files": [
+    "binding.gyp",
+    "deps/",
+    "lib/*.js",
+    "lib/*.d.ts",
+    "src/"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/TryGhost/node-sqlite3.git"
+  },
+  "dependencies": {
+    "bindings": "^1.5.0",
+    "node-addon-api": "^7.0.0",
+    "prebuild-install": "^7.1.1",
+    "tar": "^6.1.11"
+  },
+  "devDependencies": {
+    "eslint": "8.56.0",
+    "mocha": "10.2.0",
+    "prebuild": "12.1.0"
+  },
+  "peerDependencies": {
+    "node-gyp": "8.x"
+  },
+  "peerDependenciesMeta": {
+    "node-gyp": {
+      "optional": true
+    }
+  },
+  "optionalDependencies": {
+    "node-gyp": "8.x"
+  },
+  "scripts": {
+    "install": "prebuild-install -r napi || node-gyp rebuild",
+    "prebuild": "prebuild --runtime napi --all --verbose",
+    "rebuild": "node-gyp rebuild",
+    "upload": "prebuild --verbose --prerelease",
+    "test": "node test/support/createdb.js && mocha -R spec --timeout 480000"
+  },
+  "license": "BSD-3-Clause",
+  "keywords": [
+    "sql",
+    "sqlite",
+    "sqlite3",
+    "database"
+  ],
+  "main": "./lib/sqlite3",
+  "types": "./lib/sqlite3.d.ts",
+  "renovate": {
+    "extends": [
+      "@tryghost:base"
+    ]
+  }
+}
diff --git a/server/node_modules/sqlite3/src/async.h b/server/node_modules/sqlite3/src/async.h
new file mode 100644
index 0000000..f36e4cb
--- /dev/null
+++ b/server/node_modules/sqlite3/src/async.h
@@ -0,0 +1,76 @@
+#ifndef NODE_SQLITE3_SRC_ASYNC_H
+#define NODE_SQLITE3_SRC_ASYNC_H
+
+#include <napi.h>
+#include <uv.h>
+
+#include "threading.h"
+
+// Generic uv_async handler.
+template <class Item, class Parent> class Async {
+    typedef void (*Callback)(Parent* parent, Item* item);
+
+protected:
+    uv_async_t watcher;
+    NODE_SQLITE3_MUTEX_t
+    std::vector<Item*> data;
+    Callback callback;
+public:
+    Parent* parent;
+
+public:
+    Async(Parent* parent_, Callback cb_)
+        : callback(cb_), parent(parent_) {
+        watcher.data = this;
+        NODE_SQLITE3_MUTEX_INIT
+        uv_loop_t *loop;
+        napi_get_uv_event_loop(parent_->Env(), &loop);
+        uv_async_init(loop, &watcher, reinterpret_cast<uv_async_cb>(listener));
+    }
+
+    static void listener(uv_async_t* handle) {
+        auto* async = static_cast<Async*>(handle->data);
+        std::vector<Item*> rows;
+        NODE_SQLITE3_MUTEX_LOCK(&async->mutex)
+        rows.swap(async->data);
+        NODE_SQLITE3_MUTEX_UNLOCK(&async->mutex)
+        for(auto row : rows)
+            async->callback(async->parent, row);
+    }
+
+    static void close(uv_handle_t* handle) {
+        assert(handle != NULL);
+        assert(handle->data != NULL);
+        auto* async = static_cast<Async*>(handle->data);
+        delete async;
+    }
+
+    void finish() {
+        // Need to call the listener again to ensure all items have been
+        // processed. Is this a bug in uv_async? Feels like uv_close
+        // should handle that.
+        listener(&watcher);
+        uv_close((uv_handle_t*)&watcher, close);
+    }
+
+    void add(Item* item) {
+        NODE_SQLITE3_MUTEX_LOCK(&mutex);
+        data.emplace_back(item);
+        NODE_SQLITE3_MUTEX_UNLOCK(&mutex)
+    }
+
+    void send() {
+        uv_async_send(&watcher);
+    }
+
+    void send(Item* item) {
+        add(item);
+        send();
+    }
+
+    ~Async() {
+        NODE_SQLITE3_MUTEX_DESTROY
+    }
+};
+
+#endif
diff --git a/server/node_modules/sqlite3/src/backup.cc b/server/node_modules/sqlite3/src/backup.cc
new file mode 100644
index 0000000..0f971f5
--- /dev/null
+++ b/server/node_modules/sqlite3/src/backup.cc
@@ -0,0 +1,418 @@
+#include <cstring>
+#include <napi.h>
+#include "macros.h"
+#include "database.h"
+#include "backup.h"
+
+using namespace node_sqlite3;
+
+Napi::Object Backup::Init(Napi::Env env, Napi::Object exports) {
+    Napi::HandleScope scope(env);
+
+    // declare napi_default_method here as it is only available in Node v14.12.0+
+    auto napi_default_method = static_cast<napi_property_attributes>(napi_writable | napi_configurable);
+
+    auto t = DefineClass(env, "Backup", {
+        InstanceMethod("step", &Backup::Step, napi_default_method),
+        InstanceMethod("finish", &Backup::Finish, napi_default_method),
+        InstanceAccessor("idle", &Backup::IdleGetter, nullptr),
+        InstanceAccessor("completed", &Backup::CompletedGetter, nullptr),
+        InstanceAccessor("failed", &Backup::FailedGetter, nullptr),
+        InstanceAccessor("remaining", &Backup::RemainingGetter, nullptr),
+        InstanceAccessor("pageCount", &Backup::PageCountGetter, nullptr),
+        InstanceAccessor("retryErrors", &Backup::RetryErrorGetter, &Backup::RetryErrorSetter),
+    });
+
+    exports.Set("Backup", t);
+    return exports;
+}
+
+void Backup::Process() {
+    if (finished && !queue.empty()) {
+        return CleanQueue();
+    }
+
+    while (inited && !locked && !queue.empty()) {
+        auto call = std::move(queue.front());
+        queue.pop();
+
+        call->callback(call->baton);
+    }
+}
+
+void Backup::Schedule(Work_Callback callback, Baton* baton) {
+    if (finished) {
+        queue.emplace(new Call(callback, baton));
+        CleanQueue();
+    }
+    else if (!inited || locked || !queue.empty()) {
+        queue.emplace(new Call(callback, baton));
+    }
+    else {
+        callback(baton);
+    }
+}
+
+template <class T> void Backup::Error(T* baton) {
+    auto env = baton->backup->Env();
+    Napi::HandleScope scope(env);
+
+    Backup* backup = baton->backup;
+    // Fail hard on logic errors.
+    assert(backup->status != 0);
+    EXCEPTION(Napi::String::New(env, backup->message), backup->status, exception);
+
+    Napi::Function cb = baton->callback.Value();
+
+    if (!cb.IsEmpty() && cb.IsFunction()) {
+        Napi::Value argv[] = { exception };
+        TRY_CATCH_CALL(backup->Value(), cb, 1, argv);
+    }
+    else {
+        Napi::Value argv[] = { Napi::String::New(env, "error"), exception };
+        EMIT_EVENT(backup->Value(), 2, argv);
+    }
+}
+
+void Backup::CleanQueue() {
+    auto env = this->Env();
+    Napi::HandleScope scope(env);
+
+    if (inited && !queue.empty()) {
+        // This backup has already been initialized and is now finished.
+        // Fire error for all remaining items in the queue.
+        EXCEPTION(Napi::String::New(env, "Backup is already finished"), SQLITE_MISUSE, exception);
+        Napi::Value argv[] = { exception };
+        bool called = false;
+
+        // Clear out the queue so that this object can get GC'ed.
+        while (!queue.empty()) {
+            auto call = std::move(queue.front());
+            queue.pop();
+
+            std::unique_ptr<Baton> baton(call->baton);
+            Napi::Function cb = baton->callback.Value();
+
+            if (inited && !cb.IsEmpty() &&
+                cb.IsFunction()) {
+                TRY_CATCH_CALL(Value(), cb, 1, argv);
+                called = true;
+            }
+        }
+
+        // When we couldn't call a callback function, emit an error on the
+        // Backup object.
+        if (!called) {
+            Napi::Value info[] = { Napi::String::New(env, "error"), exception };
+            EMIT_EVENT(Value(), 2, info);
+        }
+    }
+    else while (!queue.empty()) {
+        // Just delete all items in the queue; we already fired an event when
+        // initializing the backup failed.
+        auto call = std::move(queue.front());
+        queue.pop();
+
+        // We don't call the actual callback, so we have to make sure that
+        // the baton gets destroyed.
+        delete call->baton;
+    }
+}
+
+Backup::Backup(const Napi::CallbackInfo& info) : Napi::ObjectWrap<Backup>(info) {
+    auto env = info.Env();
+    if (!info.IsConstructCall()) {
+        Napi::TypeError::New(env, "Use the new operator to create new Backup objects").ThrowAsJavaScriptException();
+        return;
+    }
+
+    auto length = info.Length();
+
+    if (length <= 0 || !Database::HasInstance(info[0])) {
+        Napi::TypeError::New(env, "Database object expected").ThrowAsJavaScriptException();
+        return;
+    }
+    else if (length <= 1 || !info[1].IsString()) {
+        Napi::TypeError::New(env, "Filename expected").ThrowAsJavaScriptException();
+        return;
+    }
+    else if (length <= 2 || !info[2].IsString()) {
+        Napi::TypeError::New(env, "Source database name expected").ThrowAsJavaScriptException();
+        return;
+    }
+    else if (length <= 3 || !info[3].IsString()) {
+        Napi::TypeError::New(env, "Destination database name expected").ThrowAsJavaScriptException();
+        return;
+    }
+    else if (length <= 4 || !info[4].IsBoolean()) {
+        Napi::TypeError::New(env, "Direction flag expected").ThrowAsJavaScriptException();
+        return;
+    }
+    else if (length > 5 && !info[5].IsUndefined() && !info[5].IsFunction()) {
+        Napi::TypeError::New(env, "Callback expected").ThrowAsJavaScriptException();
+        return;
+    }
+
+    this->db = Napi::ObjectWrap<Database>::Unwrap(info[0].As<Napi::Object>());
+    this->db->Ref();
+
+    auto filename = info[1].As<Napi::String>();
+    auto sourceName = info[2].As<Napi::String>();
+    auto destName = info[3].As<Napi::String>();
+    auto filenameIsDest = info[4].As<Napi::Boolean>();
+
+    info.This().As<Napi::Object>().DefineProperty(Napi::PropertyDescriptor::Value("filename", filename));
+    info.This().As<Napi::Object>().DefineProperty(Napi::PropertyDescriptor::Value("sourceName", sourceName));
+    info.This().As<Napi::Object>().DefineProperty(Napi::PropertyDescriptor::Value("destName", destName));
+    info.This().As<Napi::Object>().DefineProperty(Napi::PropertyDescriptor::Value("filenameIsDest", filenameIsDest));
+
+    auto* baton = new InitializeBaton(this->db, info[5].As<Napi::Function>(), this);
+    baton->filename = filename.Utf8Value();
+    baton->sourceName = sourceName.Utf8Value();
+    baton->destName = destName.Utf8Value();
+    baton->filenameIsDest = filenameIsDest.Value();
+
+    this->db->Schedule(Work_BeginInitialize, baton);
+}
+
+void Backup::Work_BeginInitialize(Database::Baton* baton) {
+    assert(baton->db->open);
+    baton->db->pending++;
+    auto env = baton->db->Env();
+    CREATE_WORK("sqlite3.Backup.Initialize", Work_Initialize, Work_AfterInitialize);
+}
+
+void Backup::Work_Initialize(napi_env e, void* data) {
+    BACKUP_INIT(InitializeBaton);
+
+    // In case stepping fails, we use a mutex to make sure we get the associated
+    // error message.
+    auto* mtx = sqlite3_db_mutex(baton->db->_handle);
+    sqlite3_mutex_enter(mtx);
+
+    backup->status = sqlite3_open(baton->filename.c_str(), &backup->_otherDb);
+
+    if (backup->status == SQLITE_OK) {
+        backup->_handle = sqlite3_backup_init(
+            baton->filenameIsDest ? backup->_otherDb : backup->db->_handle,
+            baton->destName.c_str(),
+            baton->filenameIsDest ? backup->db->_handle : backup->_otherDb,
+            baton->sourceName.c_str());
+    }
+    backup->_destDb = baton->filenameIsDest ? backup->_otherDb : backup->db->_handle;
+
+    if (backup->status != SQLITE_OK) {
+        backup->message = std::string(sqlite3_errmsg(backup->_destDb));
+        sqlite3_close(backup->_otherDb);
+        backup->_otherDb = NULL;
+        backup->_destDb = NULL;
+    }
+
+    sqlite3_mutex_leave(mtx);
+}
+
+void Backup::Work_AfterInitialize(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<InitializeBaton> baton(static_cast<InitializeBaton*>(data));
+    auto* backup = baton->backup;
+
+    auto env = backup->Env();
+    Napi::HandleScope scope(env);
+
+    if (backup->status != SQLITE_OK) {
+        Error(baton.get());
+        backup->FinishAll();
+    }
+    else {
+        backup->inited = true;
+        Napi::Function cb = baton->callback.Value();
+        if (!cb.IsEmpty() && cb.IsFunction()) {
+            Napi::Value argv[] = { env.Null() };
+            TRY_CATCH_CALL(backup->Value(), cb, 1, argv);
+        }
+    }
+    BACKUP_END();
+}
+
+Napi::Value Backup::Step(const Napi::CallbackInfo& info) {
+    auto* backup = this;
+    auto env = backup->Env();
+
+    REQUIRE_ARGUMENT_INTEGER(0, pages);
+    OPTIONAL_ARGUMENT_FUNCTION(1, callback);
+
+    auto* baton = new StepBaton(backup, callback, pages);
+    backup->GetRetryErrors(baton->retryErrorsSet);
+    backup->Schedule(Work_BeginStep, baton);
+    return info.This();
+}
+
+void Backup::Work_BeginStep(Baton* baton) {
+    BACKUP_BEGIN(Step);
+}
+
+void Backup::Work_Step(napi_env e, void* data) {
+    BACKUP_INIT(StepBaton);
+    if (backup->_handle) {
+        backup->status = sqlite3_backup_step(backup->_handle, baton->pages);
+        backup->remaining = sqlite3_backup_remaining(backup->_handle);
+        backup->pageCount = sqlite3_backup_pagecount(backup->_handle);
+    }
+    if (backup->status != SQLITE_OK) {
+        // Text of message is a little awkward to get, since the error is not associated
+        // with a db connection.
+#if SQLITE_VERSION_NUMBER >= 3007015
+        // sqlite3_errstr is a relatively new method
+        backup->message = std::string(sqlite3_errstr(backup->status));
+#else
+        backup->message = "Sqlite error";
+#endif
+        if (baton->retryErrorsSet.size() > 0) {
+            if (baton->retryErrorsSet.find(backup->status) == baton->retryErrorsSet.end()) {
+                backup->FinishSqlite();
+            }
+        }
+    }
+}
+
+void Backup::Work_AfterStep(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<StepBaton> baton(static_cast<StepBaton*>(data));
+    auto* backup = baton->backup;
+
+    auto env = backup->Env();
+    Napi::HandleScope scope(env);
+
+    if (backup->status == SQLITE_DONE) {
+        backup->completed = true;
+    } else if (!backup->_handle) {
+        backup->failed = true;
+    }
+
+    if (backup->status != SQLITE_OK && backup->status != SQLITE_DONE) {
+        Error(baton.get());
+    }
+    else {
+        // Fire callbacks.
+        Napi::Function cb = baton->callback.Value();
+        if (!cb.IsEmpty() && cb.IsFunction()) {
+            Napi::Value argv[] = { env.Null(), Napi::Boolean::New(env, backup->status == SQLITE_DONE) };
+            TRY_CATCH_CALL(backup->Value(), cb, 2, argv);
+        }
+    }
+
+    BACKUP_END();
+}
+
+Napi::Value Backup::Finish(const Napi::CallbackInfo& info) {
+    auto* backup = this;
+    auto env = backup->Env();
+
+    OPTIONAL_ARGUMENT_FUNCTION(0, callback);
+
+    auto* baton = new Baton(backup, callback);
+    backup->Schedule(Work_BeginFinish, baton);
+    return info.This();
+}
+
+void Backup::Work_BeginFinish(Baton* baton) {
+    BACKUP_BEGIN(Finish);
+}
+
+void Backup::Work_Finish(napi_env e, void* data) {
+    BACKUP_INIT(Baton);
+    backup->FinishSqlite();
+}
+
+void Backup::Work_AfterFinish(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<Baton> baton(static_cast<Baton*>(data));
+    auto* backup = baton->backup;
+
+    auto env = backup->Env();
+    Napi::HandleScope scope(env);
+
+    backup->FinishAll();
+
+    // Fire callback in case there was one.
+    Napi::Function cb = baton->callback.Value();
+    if (!cb.IsEmpty() && cb.IsFunction()) {
+        TRY_CATCH_CALL(backup->Value(), cb, 0, NULL);
+    }
+
+    BACKUP_END();
+}
+
+void Backup::FinishAll() {
+    assert(!finished);
+    if (!completed && !failed) {
+        failed = true;
+    }
+    finished = true;
+    CleanQueue();
+    FinishSqlite();
+    db->Unref();
+}
+
+void Backup::FinishSqlite() {
+    if (_handle) {
+        sqlite3_backup_finish(_handle);
+        _handle = NULL;
+    }
+    if (_otherDb) {
+        sqlite3_close(_otherDb);
+        _otherDb = NULL;
+    }
+    _destDb = NULL;
+}
+
+Napi::Value Backup::IdleGetter(const Napi::CallbackInfo& info) {
+    auto* backup = this;
+    bool idle = backup->inited && !backup->locked && backup->queue.empty();
+    return Napi::Boolean::New(this->Env(), idle);
+}
+
+Napi::Value Backup::CompletedGetter(const Napi::CallbackInfo& info) {
+    auto* backup = this;
+    return Napi::Boolean::New(this->Env(), backup->completed);
+}
+
+Napi::Value Backup::FailedGetter(const Napi::CallbackInfo& info) {
+    auto* backup = this;
+    return Napi::Boolean::New(this->Env(), backup->failed);
+}
+
+Napi::Value Backup::RemainingGetter(const Napi::CallbackInfo& info) {
+    auto* backup = this;
+    return Napi::Number::New(this->Env(), backup->remaining);
+}
+
+Napi::Value Backup::PageCountGetter(const Napi::CallbackInfo& info) {
+    auto* backup = this;
+    return Napi::Number::New(this->Env(), backup->pageCount);
+}
+
+Napi::Value Backup::RetryErrorGetter(const Napi::CallbackInfo& info) {
+    auto* backup = this;
+    return backup->retryErrors.Value();
+}
+
+void Backup::RetryErrorSetter(const Napi::CallbackInfo& info, const Napi::Value& value) {
+    auto* backup = this;
+    auto env = backup->Env();
+    if (!value.IsArray()) {
+        Napi::Error::New(env, "retryErrors must be an array").ThrowAsJavaScriptException();
+        return;
+    }
+    Napi::Array array = value.As<Napi::Array>();
+    backup->retryErrors.Reset(array, 1);
+}
+
+void Backup::GetRetryErrors(std::set<int>& retryErrorsSet) {
+    retryErrorsSet.clear();
+    Napi::Array array = retryErrors.Value();
+    auto length = array.Length();
+    for (size_t i = 0; i < length; i++) {
+        Napi::Value code = (array).Get(static_cast<uint32_t>(i));
+        if (code.IsNumber()) {
+            retryErrorsSet.insert(code.As<Napi::Number>().Int32Value());
+        }
+    }
+}
diff --git a/server/node_modules/sqlite3/src/backup.h b/server/node_modules/sqlite3/src/backup.h
new file mode 100644
index 0000000..b894aca
--- /dev/null
+++ b/server/node_modules/sqlite3/src/backup.h
@@ -0,0 +1,209 @@
+#ifndef NODE_SQLITE3_SRC_BACKUP_H
+#define NODE_SQLITE3_SRC_BACKUP_H
+
+#include "database.h"
+
+#include <string>
+#include <queue>
+#include <set>
+
+#include <sqlite3.h>
+#include <napi.h>
+
+using namespace Napi;
+
+namespace node_sqlite3 {
+
+/**
+ *
+ * A class for managing an sqlite3_backup object.  For consistency
+ * with other node-sqlite3 classes, it maintains an internal queue
+ * of calls.
+ *
+ * Intended usage from node:
+ *
+ *   var db = new sqlite3.Database('live.db');
+ *   var backup = db.backup('backup.db');
+ *   ...
+ *   // in event loop, move backup forward when we have time.
+ *   if (backup.idle) { backup.step(NPAGES); }
+ *   if (backup.completed) { ... success ... }
+ *   if (backup.failed)    { ... sadness ... }
+ *   // do other work in event loop - fine to modify live.db
+ *   ...
+ *
+ * Here is how sqlite's backup api is exposed:
+ *
+ *   - `sqlite3_backup_init`: This is implemented as
+ *     `db.backup(filename, [callback])` or
+ *     `db.backup(filename, destDbName, sourceDbName, filenameIsDest, [callback])`.
+ *   - `sqlite3_backup_step`: `backup.step(pages, [callback])`.
+ *   - `sqlite3_backup_finish`: `backup.finish([callback])`.
+ *   - `sqlite3_backup_remaining`: `backup.remaining`.
+ *   - `sqlite3_backup_pagecount`: `backup.pageCount`.
+ *
+ * There are the following read-only properties:
+ *
+ *   - `backup.completed` is set to `true` when the backup
+ *     succeeeds.
+ *   - `backup.failed` is set to `true` when the backup
+ *     has a fatal error.
+ *   - `backup.idle` is set to `true` when no operation
+ *     is currently in progress or queued for the backup.
+ *   - `backup.remaining` is an integer with the remaining
+ *     number of pages after the last call to `backup.step`
+ *     (-1 if `step` not yet called).
+ *   - `backup.pageCount` is an integer with the total number
+ *     of pages measured during the last call to `backup.step`
+ *     (-1 if `step` not yet called).
+ *
+ * There is the following writable property:
+ *
+ *   - `backup.retryErrors`: an array of sqlite3 error codes
+ *     that are treated as non-fatal - meaning, if they occur,
+ *     backup.failed is not set, and the backup may continue.
+ *     By default, this is `[sqlite3.BUSY, sqlite3.LOCKED]`.
+ *
+ * The `db.backup(filename, [callback])` shorthand is sufficient
+ * for making a backup of a database opened by node-sqlite3.  If
+ * using attached or temporary databases, or moving data in the
+ * opposite direction, the more complete (but daunting)
+ * `db.backup(filename, destDbName, sourceDbName, filenameIsDest, [callback])`
+ * signature is provided.
+ *
+ * A backup will finish automatically when it succeeds or a fatal
+ * error occurs, meaning it is not necessary to call `db.finish()`.
+ * By default, SQLITE_LOCKED and SQLITE_BUSY errors are not
+ * treated as failures, and the backup will continue if they
+ * occur.  The set of errors that are tolerated can be controlled
+ * by setting `backup.retryErrors`. To disable automatic
+ * finishing and stick strictly to sqlite's raw api, set
+ * `backup.retryErrors` to `[]`.  In that case, it is necessary
+ * to call `backup.finish()`.
+ *
+ * In the same way as node-sqlite3 databases and statements,
+ * backup methods can be called safely without callbacks, due
+ * to an internal call queue.  So for example this naive code
+ * will correctly back up a db, if there are no errors:
+ *
+ *   var backup = db.backup('backup.db');
+ *   backup.step(-1);
+ *   backup.finish();
+ *
+ */
+class Backup : public Napi::ObjectWrap<Backup> {
+public:
+    static Napi::Object Init(Napi::Env env, Napi::Object exports);
+
+    struct Baton {
+        napi_async_work request = NULL;
+        Backup* backup;
+        Napi::FunctionReference callback;
+
+        Baton(Backup* backup_, Napi::Function cb_) : backup(backup_) {
+            backup->Ref();
+            callback.Reset(cb_, 1);
+        }
+        virtual ~Baton() {
+            if (request) napi_delete_async_work(backup->Env(), request);
+            backup->Unref();
+            callback.Reset();
+        }
+    };
+
+    struct InitializeBaton : Database::Baton {
+        Backup* backup;
+        std::string filename;
+        std::string sourceName;
+        std::string destName;
+        bool filenameIsDest;
+        InitializeBaton(Database* db_, Napi::Function cb_, Backup* backup_) :
+            Baton(db_, cb_), backup(backup_), filenameIsDest(true) {
+            backup->Ref();
+        }
+        virtual ~InitializeBaton() override {
+            backup->Unref();
+            if (!db->IsOpen() && db->IsLocked()) {
+                // The database handle was closed before the backup could be opened.
+                backup->FinishAll();
+            }
+        }
+    };
+
+    struct StepBaton : Baton {
+        int pages;
+        std::set<int> retryErrorsSet;
+        StepBaton(Backup* backup_, Napi::Function cb_, int pages_) :
+            Baton(backup_, cb_), pages(pages_) {}
+        virtual ~StepBaton() override = default;
+    };
+
+    typedef void (*Work_Callback)(Baton* baton);
+
+    struct Call {
+        Call(Work_Callback cb_, Baton* baton_) : callback(cb_), baton(baton_) {};
+        Work_Callback callback;
+        Baton* baton;
+    };
+
+    Backup(const Napi::CallbackInfo& info);
+
+    ~Backup() {
+        if (!finished) {
+            FinishAll();
+        }
+        retryErrors.Reset();
+    }
+
+    WORK_DEFINITION(Step)
+    WORK_DEFINITION(Finish)
+
+    Napi::Value IdleGetter(const Napi::CallbackInfo& info);
+    Napi::Value CompletedGetter(const Napi::CallbackInfo& info);
+    Napi::Value FailedGetter(const Napi::CallbackInfo& info);
+    Napi::Value PageCountGetter(const Napi::CallbackInfo& info);
+    Napi::Value RemainingGetter(const Napi::CallbackInfo& info);
+    Napi::Value FatalErrorGetter(const Napi::CallbackInfo& info);
+    Napi::Value RetryErrorGetter(const Napi::CallbackInfo& info);
+
+    void FatalErrorSetter(const Napi::CallbackInfo& info, const Napi::Value& value);
+    void RetryErrorSetter(const Napi::CallbackInfo& info, const Napi::Value& value);
+
+protected:
+    static void Work_BeginInitialize(Database::Baton* baton);
+    static void Work_Initialize(napi_env env, void* data);
+    static void Work_AfterInitialize(napi_env env, napi_status status, void* data);
+
+    void Schedule(Work_Callback callback, Baton* baton);
+    void Process();
+    void CleanQueue();
+    template <class T> static void Error(T* baton);
+
+    void FinishAll();
+    void FinishSqlite();
+    void GetRetryErrors(std::set<int>& retryErrorsSet);
+
+    Database* db;
+
+    sqlite3_backup* _handle = NULL;
+    sqlite3* _otherDb = NULL;
+    sqlite3* _destDb = NULL;
+
+    bool inited = false;
+    bool locked = true;
+    bool completed = false;
+    bool failed = false;
+    int remaining = -1;
+    int pageCount = -1;
+    bool finished = false;
+
+    int status;
+    std::string message;
+    std::queue<std::unique_ptr<Call>> queue;
+
+    Napi::Reference<Array> retryErrors;
+};
+
+}
+
+#endif
diff --git a/server/node_modules/sqlite3/src/database.cc b/server/node_modules/sqlite3/src/database.cc
new file mode 100644
index 0000000..d495ce9
--- /dev/null
+++ b/server/node_modules/sqlite3/src/database.cc
@@ -0,0 +1,751 @@
+#include <cstring>
+#include <napi.h>
+
+#include "macros.h"
+#include "database.h"
+#include "statement.h"
+
+using namespace node_sqlite3;
+
+#if NAPI_VERSION < 6
+Napi::FunctionReference Database::constructor;
+#endif
+
+Napi::Object Database::Init(Napi::Env env, Napi::Object exports) {
+    Napi::HandleScope scope(env);
+    // declare napi_default_method here as it is only available in Node v14.12.0+
+    auto napi_default_method = static_cast<napi_property_attributes>(napi_writable | napi_configurable); 
+
+    auto t = DefineClass(env, "Database", {
+        InstanceMethod("close", &Database::Close, napi_default_method),
+        InstanceMethod("exec", &Database::Exec, napi_default_method),
+        InstanceMethod("wait", &Database::Wait, napi_default_method),
+        InstanceMethod("loadExtension", &Database::LoadExtension, napi_default_method),
+        InstanceMethod("serialize", &Database::Serialize, napi_default_method),
+        InstanceMethod("parallelize", &Database::Parallelize, napi_default_method),
+        InstanceMethod("configure", &Database::Configure, napi_default_method),
+        InstanceMethod("interrupt", &Database::Interrupt, napi_default_method),
+        InstanceAccessor("open", &Database::Open, nullptr)
+    });
+
+#if NAPI_VERSION < 6
+    constructor = Napi::Persistent(t);
+    constructor.SuppressDestruct();
+#else
+    Napi::FunctionReference* constructor = new Napi::FunctionReference();
+    *constructor = Napi::Persistent(t);
+    env.SetInstanceData<Napi::FunctionReference>(constructor);
+#endif
+
+    exports.Set("Database", t);
+    return exports;
+}
+
+void Database::Process() {
+    auto env = this->Env();
+    Napi::HandleScope scope(env);
+
+    if (!open && locked && !queue.empty()) {
+        EXCEPTION(Napi::String::New(env, "Database handle is closed"), SQLITE_MISUSE, exception);
+        Napi::Value argv[] = { exception };
+        bool called = false;
+
+        // Call all callbacks with the error object.
+        while (!queue.empty()) {
+            auto call = std::unique_ptr<Call>(queue.front());
+            queue.pop();
+            auto baton = std::unique_ptr<Baton>(call->baton);
+            Napi::Function cb = baton->callback.Value();
+            if (IS_FUNCTION(cb)) {
+                TRY_CATCH_CALL(this->Value(), cb, 1, argv);
+                called = true;
+            }
+        }
+
+        // When we couldn't call a callback function, emit an error on the
+        // Database object.
+        if (!called) {
+            Napi::Value info[] = { Napi::String::New(env, "error"), exception };
+            EMIT_EVENT(Value(), 2, info);
+        }
+        return;
+    }
+
+    while (open && (!locked || pending == 0) && !queue.empty()) {
+        Call *c = queue.front();
+
+        if (c->exclusive && pending > 0) {
+            break;
+        }
+
+        queue.pop();
+        std::unique_ptr<Call> call(c);
+        locked = call->exclusive;
+        call->callback(call->baton);
+
+        if (locked) break;
+    }
+}
+
+void Database::Schedule(Work_Callback callback, Baton* baton, bool exclusive) {
+    auto env = this->Env();
+    Napi::HandleScope scope(env);
+
+    if (!open && locked) {
+        EXCEPTION(Napi::String::New(env, "Database is closed"), SQLITE_MISUSE, exception);
+        Napi::Function cb = baton->callback.Value();
+        // We don't call the actual callback, so we have to make sure that
+        // the baton gets destroyed.
+        delete baton;
+        if (IS_FUNCTION(cb)) {
+            Napi::Value argv[] = { exception };
+            TRY_CATCH_CALL(Value(), cb, 1, argv);
+        }
+        else {
+            Napi::Value argv[] = { Napi::String::New(env, "error"), exception };
+            EMIT_EVENT(Value(), 2, argv);
+        }
+        return;
+    }
+
+    if (!open || ((locked || exclusive || serialize) && pending > 0)) {
+        queue.emplace(new Call(callback, baton, exclusive || serialize));
+    }
+    else {
+        locked = exclusive;
+        callback(baton);
+    }
+}
+
+Database::Database(const Napi::CallbackInfo& info) : Napi::ObjectWrap<Database>(info) {
+    auto env = info.Env();
+
+    if (info.Length() <= 0 || !info[0].IsString()) {
+        Napi::TypeError::New(env, "String expected").ThrowAsJavaScriptException();
+        return;
+    }
+    auto filename = info[0].As<Napi::String>().Utf8Value();
+
+    unsigned int pos = 1;
+
+    int mode;
+    if (info.Length() >= pos && info[pos].IsNumber() && OtherIsInt(info[pos].As<Napi::Number>())) {
+        mode = info[pos++].As<Napi::Number>().Int32Value();
+    }
+    else {
+        mode = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FULLMUTEX;
+    }
+
+    Napi::Function callback;
+    if (info.Length() >= pos && info[pos].IsFunction()) {
+        callback = info[pos++].As<Napi::Function>();
+    }
+
+    info.This().As<Napi::Object>().DefineProperty(Napi::PropertyDescriptor::Value("filename", info[0].As<Napi::String>(), napi_default));
+    info.This().As<Napi::Object>().DefineProperty(Napi::PropertyDescriptor::Value("mode", Napi::Number::New(env, mode), napi_default));
+
+    // Start opening the database.
+    auto* baton = new OpenBaton(this, callback, filename.c_str(), mode);
+    Work_BeginOpen(baton);
+}
+
+void Database::Work_BeginOpen(Baton* baton) {
+    auto env = baton->db->Env();
+    CREATE_WORK("sqlite3.Database.Open", Work_Open, Work_AfterOpen);
+}
+
+void Database::Work_Open(napi_env e, void* data) {
+    auto* baton = static_cast<OpenBaton*>(data);
+    auto* db = baton->db;
+
+    baton->status = sqlite3_open_v2(
+        baton->filename.c_str(),
+        &db->_handle,
+        baton->mode,
+        NULL
+    );
+
+    if (baton->status != SQLITE_OK) {
+        baton->message = std::string(sqlite3_errmsg(db->_handle));
+        sqlite3_close(db->_handle);
+        db->_handle = NULL;
+    }
+    else {
+        // Set default database handle values.
+        sqlite3_busy_timeout(db->_handle, 1000);
+    }
+}
+
+void Database::Work_AfterOpen(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<OpenBaton> baton(static_cast<OpenBaton*>(data));
+
+    auto* db = baton->db;
+
+    auto env = db->Env();
+    Napi::HandleScope scope(env);
+
+    Napi::Value argv[1];
+    if (baton->status != SQLITE_OK) {
+        EXCEPTION(Napi::String::New(env, baton->message.c_str()), baton->status, exception);
+        argv[0] = exception;
+    }
+    else {
+        db->open = true;
+        argv[0] = env.Null();
+    }
+
+    Napi::Function cb = baton->callback.Value();
+
+    if (IS_FUNCTION(cb)) {
+        TRY_CATCH_CALL(db->Value(), cb, 1, argv);
+    }
+    else if (!db->open) {
+        Napi::Value info[] = { Napi::String::New(env, "error"), argv[0] };
+        EMIT_EVENT(db->Value(), 2, info);
+    }
+
+    if (db->open) {
+        Napi::Value info[] = { Napi::String::New(env, "open") };
+        EMIT_EVENT(db->Value(), 1, info);
+        db->Process();
+    }
+}
+
+Napi::Value Database::Open(const Napi::CallbackInfo& info) {
+    auto env = this->Env();
+    auto* db = this;
+    return Napi::Boolean::New(env, db->open);
+}
+
+Napi::Value Database::Close(const Napi::CallbackInfo& info) {
+    auto env = info.Env();
+    auto* db = this;
+    OPTIONAL_ARGUMENT_FUNCTION(0, callback);
+
+   auto* baton = new Baton(db, callback);
+    db->Schedule(Work_BeginClose, baton, true);
+
+    return info.This();
+}
+
+void Database::Work_BeginClose(Baton* baton) {
+    assert(baton->db->locked);
+    assert(baton->db->open);
+    assert(baton->db->_handle);
+    assert(baton->db->pending == 0);
+
+    baton->db->pending++;
+    baton->db->RemoveCallbacks();
+    baton->db->closing = true;
+
+    auto env = baton->db->Env();
+    CREATE_WORK("sqlite3.Database.Close", Work_Close, Work_AfterClose);
+}
+
+void Database::Work_Close(napi_env e, void* data) {
+    auto* baton = static_cast<Baton*>(data);
+    auto* db = baton->db;
+
+    baton->status = sqlite3_close(db->_handle);
+
+    if (baton->status != SQLITE_OK) {
+        baton->message = std::string(sqlite3_errmsg(db->_handle));
+    }
+    else {
+        db->_handle = NULL;
+    }
+}
+
+void Database::Work_AfterClose(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<Baton> baton(static_cast<Baton*>(data));
+
+    auto* db = baton->db;
+
+    auto env = db->Env();
+    Napi::HandleScope scope(env);
+
+    db->pending--;
+    db->closing = false;
+
+    Napi::Value argv[1];
+    if (baton->status != SQLITE_OK) {
+        EXCEPTION(Napi::String::New(env, baton->message.c_str()), baton->status, exception);
+        argv[0] = exception;
+    }
+    else {
+        db->open = false;
+        // Leave db->locked to indicate that this db object has reached
+        // the end of its life.
+        argv[0] = env.Null();
+    }
+
+    Napi::Function cb = baton->callback.Value();
+
+    // Fire callbacks.
+    if (IS_FUNCTION(cb)) {
+        TRY_CATCH_CALL(db->Value(), cb, 1, argv);
+    }
+    else if (db->open) {
+        Napi::Value info[] = { Napi::String::New(env, "error"), argv[0] };
+        EMIT_EVENT(db->Value(), 2, info);
+    }
+
+    if (!db->open) {
+        Napi::Value info[] = { Napi::String::New(env, "close") };
+        EMIT_EVENT(db->Value(), 1, info);
+        db->Process();
+    }
+}
+
+Napi::Value Database::Serialize(const Napi::CallbackInfo& info) {
+    auto env = this->Env();
+    auto* db = this;
+    OPTIONAL_ARGUMENT_FUNCTION(0, callback);
+
+    bool before = db->serialize;
+    db->serialize = true;
+
+    if (!callback.IsEmpty() && callback.IsFunction()) {
+        TRY_CATCH_CALL(info.This(), callback, 0, NULL, info.This());
+        db->serialize = before;
+    }
+
+    db->Process();
+
+    return info.This();
+}
+
+Napi::Value Database::Parallelize(const Napi::CallbackInfo& info) {
+    auto env = this->Env();
+    auto* db = this;
+    OPTIONAL_ARGUMENT_FUNCTION(0, callback);
+
+    auto before = db->serialize;
+    db->serialize = false;
+
+    if (!callback.IsEmpty() && callback.IsFunction()) {
+        TRY_CATCH_CALL(info.This(), callback, 0, NULL, info.This());
+        db->serialize = before;
+    }
+
+    db->Process();
+
+    return info.This();
+}
+
+Napi::Value Database::Configure(const Napi::CallbackInfo& info) {
+    auto env = this->Env();
+    auto* db = this;
+
+    REQUIRE_ARGUMENTS(2);
+
+    Napi::Function handle;
+    if (info[0].StrictEquals( Napi::String::New(env, "trace"))) {    
+       auto* baton = new Baton(db, handle);
+        db->Schedule(RegisterTraceCallback, baton);
+    }
+    else if (info[0].StrictEquals( Napi::String::New(env, "profile"))) {
+       auto* baton = new Baton(db, handle);
+        db->Schedule(RegisterProfileCallback, baton);
+    }
+    else if (info[0].StrictEquals( Napi::String::New(env, "busyTimeout"))) {
+        if (!info[1].IsNumber()) {
+            Napi::TypeError::New(env, "Value must be an integer").ThrowAsJavaScriptException();
+            return env.Null();
+        }
+       auto* baton = new Baton(db, handle);
+        baton->status = info[1].As<Napi::Number>().Int32Value();
+        db->Schedule(SetBusyTimeout, baton);
+    }
+    else if (info[0].StrictEquals( Napi::String::New(env, "limit"))) {
+        REQUIRE_ARGUMENTS(3);
+        if (!info[1].IsNumber()) {
+            Napi::TypeError::New(env, "limit id must be an integer").ThrowAsJavaScriptException();
+            return env.Null();
+        }
+        if (!info[2].IsNumber()) {
+            Napi::TypeError::New(env, "limit value must be an integer").ThrowAsJavaScriptException();
+            return env.Null();
+        }
+        int id = info[1].As<Napi::Number>().Int32Value();
+        int value = info[2].As<Napi::Number>().Int32Value();
+        Baton* baton = new LimitBaton(db, handle, id, value);
+        db->Schedule(SetLimit, baton);
+    }
+    else if (info[0].StrictEquals(Napi::String::New(env, "change"))) {
+       auto* baton = new Baton(db, handle);
+        db->Schedule(RegisterUpdateCallback, baton);
+    }
+    else {
+        Napi::TypeError::New(env, (StringConcat(
+#if V8_MAJOR_VERSION > 6
+            info.GetIsolate(),
+#endif
+            info[0].As<Napi::String>(),
+            Napi::String::New(env, " is not a valid configuration option")
+        )).Utf8Value().c_str()).ThrowAsJavaScriptException();
+        return env.Null();
+    }
+
+    db->Process();
+
+    return info.This();
+}
+
+Napi::Value Database::Interrupt(const Napi::CallbackInfo& info) {
+    auto env = this->Env();
+    auto* db = this;
+
+    if (!db->open) {
+        Napi::Error::New(env, "Database is not open").ThrowAsJavaScriptException();
+        return env.Null();
+    }
+
+    if (db->closing) {
+        Napi::Error::New(env, "Database is closing").ThrowAsJavaScriptException();
+        return env.Null();
+    }
+
+    sqlite3_interrupt(db->_handle);
+    return info.This();
+}
+
+void Database::SetBusyTimeout(Baton* b) {
+    auto baton = std::unique_ptr<Baton>(b);
+
+    assert(baton->db->open);
+    assert(baton->db->_handle);
+
+    // Abuse the status field for passing the timeout.
+    sqlite3_busy_timeout(baton->db->_handle, baton->status);
+}
+
+void Database::SetLimit(Baton* b) {
+    std::unique_ptr<LimitBaton> baton(static_cast<LimitBaton*>(b));
+
+    assert(baton->db->open);
+    assert(baton->db->_handle);
+
+    sqlite3_limit(baton->db->_handle, baton->id, baton->value);
+}
+
+void Database::RegisterTraceCallback(Baton* b) {
+    auto baton = std::unique_ptr<Baton>(b);
+    assert(baton->db->open);
+    assert(baton->db->_handle);
+    auto* db = baton->db;
+
+    if (db->debug_trace == NULL) {
+        // Add it.
+        db->debug_trace = new AsyncTrace(db, TraceCallback);
+        sqlite3_trace(db->_handle, TraceCallback, db);
+    }
+    else {
+        // Remove it.
+        sqlite3_trace(db->_handle, NULL, NULL);
+        db->debug_trace->finish();
+        db->debug_trace = NULL;
+    }
+}
+
+void Database::TraceCallback(void* db, const char* sql) {
+    // Note: This function is called in the thread pool.
+    // Note: Some queries, such as "EXPLAIN" queries, are not sent through this.
+    static_cast<Database*>(db)->debug_trace->send(new std::string(sql));
+}
+
+void Database::TraceCallback(Database* db, std::string* s) {
+    std::unique_ptr<std::string> sql(s);
+    // Note: This function is called in the main V8 thread.
+    auto env = db->Env();
+    Napi::HandleScope scope(env);
+
+    Napi::Value argv[] = {
+        Napi::String::New(env, "trace"),
+        Napi::String::New(env, sql->c_str())
+    };
+    EMIT_EVENT(db->Value(), 2, argv);
+}
+
+void Database::RegisterProfileCallback(Baton* b) {
+    auto baton = std::unique_ptr<Baton>(b);
+    assert(baton->db->open);
+    assert(baton->db->_handle);
+    auto* db = baton->db;
+
+    if (db->debug_profile == NULL) {
+        // Add it.
+        db->debug_profile = new AsyncProfile(db, ProfileCallback);
+        sqlite3_profile(db->_handle, ProfileCallback, db);
+    }
+    else {
+        // Remove it.
+        sqlite3_profile(db->_handle, NULL, NULL);
+        db->debug_profile->finish();
+        db->debug_profile = NULL;
+    }
+}
+
+void Database::ProfileCallback(void* db, const char* sql, sqlite3_uint64 nsecs) {
+    // Note: This function is called in the thread pool.
+    // Note: Some queries, such as "EXPLAIN" queries, are not sent through this.
+    auto* info = new ProfileInfo();
+    info->sql = std::string(sql);
+    info->nsecs = nsecs;
+    static_cast<Database*>(db)->debug_profile->send(info);
+}
+
+void Database::ProfileCallback(Database *db, ProfileInfo* i) {
+    auto info = std::unique_ptr<ProfileInfo>(i);
+    auto env = db->Env();
+    Napi::HandleScope scope(env);
+
+    Napi::Value argv[] = {
+        Napi::String::New(env, "profile"),
+        Napi::String::New(env, info->sql.c_str()),
+        Napi::Number::New(env, (double)info->nsecs / 1000000.0)
+    };
+    EMIT_EVENT(db->Value(), 3, argv);
+}
+
+void Database::RegisterUpdateCallback(Baton* b) {
+    auto baton = std::unique_ptr<Baton>(b);
+    assert(baton->db->open);
+    assert(baton->db->_handle);
+    auto* db = baton->db;
+
+    if (db->update_event == NULL) {
+        // Add it.
+        db->update_event = new AsyncUpdate(db, UpdateCallback);
+        sqlite3_update_hook(db->_handle, UpdateCallback, db);
+    }
+    else {
+        // Remove it.
+        sqlite3_update_hook(db->_handle, NULL, NULL);
+        db->update_event->finish();
+        db->update_event = NULL;
+    }
+}
+
+void Database::UpdateCallback(void* db, int type, const char* database,
+        const char* table, sqlite3_int64 rowid) {
+    // Note: This function is called in the thread pool.
+    // Note: Some queries, such as "EXPLAIN" queries, are not sent through this.
+    auto* info = new UpdateInfo();
+    info->type = type;
+    info->database = std::string(database);
+    info->table = std::string(table);
+    info->rowid = rowid;
+    static_cast<Database*>(db)->update_event->send(info);
+}
+
+void Database::UpdateCallback(Database *db, UpdateInfo* i) {
+    auto info = std::unique_ptr<UpdateInfo>(i);
+    auto env = db->Env();
+    Napi::HandleScope scope(env);
+
+    Napi::Value argv[] = {
+        Napi::String::New(env, "change"),
+        Napi::String::New(env, sqlite_authorizer_string(info->type)),
+        Napi::String::New(env, info->database.c_str()),
+        Napi::String::New(env, info->table.c_str()),
+        Napi::Number::New(env, info->rowid),
+    };
+    EMIT_EVENT(db->Value(), 5, argv);
+}
+
+Napi::Value Database::Exec(const Napi::CallbackInfo& info) {
+    auto env = this->Env();
+    auto* db = this;
+
+    REQUIRE_ARGUMENT_STRING(0, sql);
+    OPTIONAL_ARGUMENT_FUNCTION(1, callback);
+
+    Baton* baton = new ExecBaton(db, callback, sql.c_str());
+    db->Schedule(Work_BeginExec, baton, true);
+
+    return info.This();
+}
+
+void Database::Work_BeginExec(Baton* baton) {
+    assert(baton->db->locked);
+    assert(baton->db->open);
+    assert(baton->db->_handle);
+    assert(baton->db->pending == 0);
+    baton->db->pending++;
+
+    auto env = baton->db->Env();
+    CREATE_WORK("sqlite3.Database.Exec", Work_Exec, Work_AfterExec);
+}
+
+void Database::Work_Exec(napi_env e, void* data) {
+    auto* baton = static_cast<ExecBaton*>(data);
+
+    char* message = NULL;
+    baton->status = sqlite3_exec(
+        baton->db->_handle,
+        baton->sql.c_str(),
+        NULL,
+        NULL,
+        &message
+    );
+
+    if (baton->status != SQLITE_OK && message != NULL) {
+        baton->message = std::string(message);
+        sqlite3_free(message);
+    }
+}
+
+void Database::Work_AfterExec(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<ExecBaton> baton(static_cast<ExecBaton*>(data));
+
+    auto* db = baton->db;
+    db->pending--;
+
+    auto env = db->Env();
+    Napi::HandleScope scope(env);
+
+    Napi::Function cb = baton->callback.Value();
+
+    if (baton->status != SQLITE_OK) {
+        EXCEPTION(Napi::String::New(env, baton->message.c_str()), baton->status, exception);
+
+        if (IS_FUNCTION(cb)) {
+            Napi::Value argv[] = { exception };
+            TRY_CATCH_CALL(db->Value(), cb, 1, argv);
+        }
+        else {
+            Napi::Value info[] = { Napi::String::New(env, "error"), exception };
+            EMIT_EVENT(db->Value(), 2, info);
+        }
+    }
+    else if (IS_FUNCTION(cb)) {
+        Napi::Value argv[] = { env.Null() };
+        TRY_CATCH_CALL(db->Value(), cb, 1, argv);
+    }
+
+    db->Process();
+}
+
+Napi::Value Database::Wait(const Napi::CallbackInfo& info) {
+    auto env = info.Env();
+    auto* db = this;
+
+    OPTIONAL_ARGUMENT_FUNCTION(0, callback);
+
+   auto* baton = new Baton(db, callback);
+    db->Schedule(Work_Wait, baton, true);
+
+    return info.This();
+}
+
+void Database::Work_Wait(Baton* b) {
+    auto baton = std::unique_ptr<Baton>(b);
+
+    auto env = baton->db->Env();
+    Napi::HandleScope scope(env);
+
+    assert(baton->db->locked);
+    assert(baton->db->open);
+    assert(baton->db->_handle);
+    assert(baton->db->pending == 0);
+
+    Napi::Function cb = baton->callback.Value();
+    if (IS_FUNCTION(cb)) {
+        Napi::Value argv[] = { env.Null() };
+        TRY_CATCH_CALL(baton->db->Value(), cb, 1, argv);
+    }
+
+    baton->db->Process();
+}
+
+Napi::Value Database::LoadExtension(const Napi::CallbackInfo& info) {
+    auto env = this->Env();
+    auto* db = this;
+
+    REQUIRE_ARGUMENT_STRING(0, filename);
+    OPTIONAL_ARGUMENT_FUNCTION(1, callback);
+
+    Baton* baton = new LoadExtensionBaton(db, callback, filename.c_str());
+    db->Schedule(Work_BeginLoadExtension, baton, true);
+
+    return info.This();
+}
+
+void Database::Work_BeginLoadExtension(Baton* baton) {
+    assert(baton->db->locked);
+    assert(baton->db->open);
+    assert(baton->db->_handle);
+    assert(baton->db->pending == 0);
+    baton->db->pending++;
+
+    auto env = baton->db->Env();
+    CREATE_WORK("sqlite3.Database.LoadExtension", Work_LoadExtension, Work_AfterLoadExtension);
+}
+
+void Database::Work_LoadExtension(napi_env e, void* data) {
+    auto* baton = static_cast<LoadExtensionBaton*>(data);
+
+    sqlite3_enable_load_extension(baton->db->_handle, 1);
+
+    char* message = NULL;
+    baton->status = sqlite3_load_extension(
+        baton->db->_handle,
+        baton->filename.c_str(),
+        0,
+        &message
+    );
+
+    sqlite3_enable_load_extension(baton->db->_handle, 0);
+
+    if (baton->status != SQLITE_OK && message != NULL) {
+        baton->message = std::string(message);
+        sqlite3_free(message);
+    }
+}
+
+void Database::Work_AfterLoadExtension(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<LoadExtensionBaton> baton(static_cast<LoadExtensionBaton*>(data));
+
+    auto* db = baton->db;
+    db->pending--;
+
+    auto env = db->Env();
+    Napi::HandleScope scope(env);
+
+    Napi::Function cb = baton->callback.Value();
+
+    if (baton->status != SQLITE_OK) {
+        EXCEPTION(Napi::String::New(env, baton->message.c_str()), baton->status, exception);
+
+        if (IS_FUNCTION(cb)) {
+            Napi::Value argv[] = { exception };
+            TRY_CATCH_CALL(db->Value(), cb, 1, argv);
+        }
+        else {
+            Napi::Value info[] = { Napi::String::New(env, "error"), exception };
+            EMIT_EVENT(db->Value(), 2, info);
+        }
+    }
+    else if (IS_FUNCTION(cb)) {
+        Napi::Value argv[] = { env.Null() };
+        TRY_CATCH_CALL(db->Value(), cb, 1, argv);
+    }
+
+    db->Process();
+}
+
+void Database::RemoveCallbacks() {
+    if (debug_trace) {
+        debug_trace->finish();
+        debug_trace = NULL;
+    }
+    if (debug_profile) {
+        debug_profile->finish();
+        debug_profile = NULL;
+    }
+    if (update_event) {
+        update_event->finish();
+        update_event = NULL;
+    }
+}
diff --git a/server/node_modules/sqlite3/src/database.h b/server/node_modules/sqlite3/src/database.h
new file mode 100644
index 0000000..8ffd300
--- /dev/null
+++ b/server/node_modules/sqlite3/src/database.h
@@ -0,0 +1,188 @@
+
+#ifndef NODE_SQLITE3_SRC_DATABASE_H
+#define NODE_SQLITE3_SRC_DATABASE_H
+
+
+#include <assert.h>
+#include <string>
+#include <queue>
+
+#include <sqlite3.h>
+#include <napi.h>
+
+#include "async.h"
+
+using namespace Napi;
+
+namespace node_sqlite3 {
+
+class Database;
+
+
+class Database : public Napi::ObjectWrap<Database> {
+public:
+#if NAPI_VERSION < 6
+    static Napi::FunctionReference constructor;
+#endif
+    static Napi::Object Init(Napi::Env env, Napi::Object exports);
+
+    static inline bool HasInstance(Napi::Value val) {
+        auto env = val.Env();
+        Napi::HandleScope scope(env);
+        if (!val.IsObject()) return false;
+        auto obj = val.As<Napi::Object>();
+#if NAPI_VERSION < 6
+        return obj.InstanceOf(constructor.Value());
+#else
+        auto constructor =
+            env.GetInstanceData<Napi::FunctionReference>();
+        return obj.InstanceOf(constructor->Value());
+#endif
+    }
+
+    struct Baton {
+        napi_async_work request = NULL;
+        Database* db;
+        Napi::FunctionReference callback;
+        int status;
+        std::string message;
+
+        Baton(Database* db_, Napi::Function cb_) :
+                db(db_), status(SQLITE_OK) {
+            db->Ref();
+            if (!cb_.IsUndefined() && cb_.IsFunction()) {
+                callback.Reset(cb_, 1);
+            }
+        }
+        virtual ~Baton() {
+            if (request) napi_delete_async_work(db->Env(), request);
+            db->Unref();
+            callback.Reset();
+        }
+    };
+
+    struct OpenBaton : Baton {
+        std::string filename;
+        int mode;
+        OpenBaton(Database* db_, Napi::Function cb_, const char* filename_, int mode_) :
+            Baton(db_, cb_), filename(filename_), mode(mode_) {}
+        virtual ~OpenBaton() override = default;
+    };
+
+    struct ExecBaton : Baton {
+        std::string sql;
+        ExecBaton(Database* db_, Napi::Function cb_, const char* sql_) :
+            Baton(db_, cb_), sql(sql_) {}
+        virtual ~ExecBaton() override = default;
+    };
+
+    struct LoadExtensionBaton : Baton {
+        std::string filename;
+        LoadExtensionBaton(Database* db_, Napi::Function cb_, const char* filename_) :
+            Baton(db_, cb_), filename(filename_) {}
+        virtual ~LoadExtensionBaton() override = default;
+    };
+
+    struct LimitBaton : Baton {
+        int id;
+        int value;
+        LimitBaton(Database* db_, Napi::Function cb_, int id_, int value_) :
+            Baton(db_, cb_), id(id_), value(value_) {}
+        virtual ~LimitBaton() override = default;
+    };
+
+    typedef void (*Work_Callback)(Baton* baton);
+
+    struct Call {
+        Call(Work_Callback cb_, Baton* baton_, bool exclusive_ = false) :
+            callback(cb_), exclusive(exclusive_), baton(baton_) {};
+        Work_Callback callback;
+        bool exclusive;
+        Baton* baton;
+    };
+
+    struct ProfileInfo {
+        std::string sql;
+        sqlite3_int64 nsecs;
+    };
+
+    struct UpdateInfo {
+        int type;
+        std::string database;
+        std::string table;
+        sqlite3_int64 rowid;
+    };
+
+    bool IsOpen() { return open; }
+    bool IsLocked() { return locked; }
+
+    typedef Async<std::string, Database> AsyncTrace;
+    typedef Async<ProfileInfo, Database> AsyncProfile;
+    typedef Async<UpdateInfo, Database> AsyncUpdate;
+
+    friend class Statement;
+    friend class Backup;
+
+    Database(const Napi::CallbackInfo& info);
+
+    ~Database() {
+        RemoveCallbacks();
+        sqlite3_close(_handle);
+        _handle = NULL;
+        open = false;
+    }
+
+protected:
+    WORK_DEFINITION(Open);
+    WORK_DEFINITION(Exec);
+    WORK_DEFINITION(Close);
+    WORK_DEFINITION(LoadExtension);
+
+    void Schedule(Work_Callback callback, Baton* baton, bool exclusive = false);
+    void Process();
+
+    Napi::Value Wait(const Napi::CallbackInfo& info);
+    static void Work_Wait(Baton* baton);
+
+    Napi::Value Serialize(const Napi::CallbackInfo& info);
+    Napi::Value Parallelize(const Napi::CallbackInfo& info);
+    Napi::Value Configure(const Napi::CallbackInfo& info);
+    Napi::Value Interrupt(const Napi::CallbackInfo& info);
+
+    static void SetBusyTimeout(Baton* baton);
+    static void SetLimit(Baton* baton);
+
+    static void RegisterTraceCallback(Baton* baton);
+    static void TraceCallback(void* db, const char* sql);
+    static void TraceCallback(Database* db, std::string* sql);
+
+    static void RegisterProfileCallback(Baton* baton);
+    static void ProfileCallback(void* db, const char* sql, sqlite3_uint64 nsecs);
+    static void ProfileCallback(Database* db, ProfileInfo* info);
+
+    static void RegisterUpdateCallback(Baton* baton);
+    static void UpdateCallback(void* db, int type, const char* database, const char* table, sqlite3_int64 rowid);
+    static void UpdateCallback(Database* db, UpdateInfo* info);
+
+    void RemoveCallbacks();
+
+protected:
+    sqlite3* _handle = NULL;
+
+    bool open = false;
+    bool closing = false;
+    bool locked = false;
+    unsigned int pending = 0;
+
+    bool serialize = false;
+
+    std::queue<Call*> queue;
+
+    AsyncTrace* debug_trace = NULL;
+    AsyncProfile* debug_profile = NULL;
+    AsyncUpdate* update_event = NULL;
+};
+
+}
+
+#endif
diff --git a/server/node_modules/sqlite3/src/gcc-preinclude.h b/server/node_modules/sqlite3/src/gcc-preinclude.h
new file mode 100644
index 0000000..7a52a4d
--- /dev/null
+++ b/server/node_modules/sqlite3/src/gcc-preinclude.h
@@ -0,0 +1,30 @@
+// http://web.archive.org/web/20140401031018/http://rjpower9000.wordpress.com:80/2012/04/09/fun-with-shared-libraries-version-glibc_2-14-not-found/
+
+#if defined(__linux__)
+
+#define _GNU_SOURCE
+#include <features.h>
+#undef _GNU_SOURCE
+
+#if defined(__USE_GNU)
+
+#if defined(__x86_64__)
+__asm__(".symver memcpy,memcpy@GLIBC_2.2.5");
+__asm__(".symver exp,exp@GLIBC_2.2.5");
+__asm__(".symver log,log@GLIBC_2.2.5");
+__asm__(".symver log2,log2@GLIBC_2.2.5");
+__asm__(".symver pow,pow@GLIBC_2.2.5");
+__asm__(".symver fcntl64,fcntl@GLIBC_2.2.5");
+#endif
+
+#if defined(__aarch64__) || defined(_M_ARM64)
+__asm__(".symver memcpy,memcpy@GLIBC_2.17");
+__asm__(".symver exp,exp@GLIBC_2.17");
+__asm__(".symver log,log@GLIBC_2.17");
+__asm__(".symver log2,log2@GLIBC_2.17");
+__asm__(".symver pow,pow@GLIBC_2.17");
+__asm__(".symver fcntl64,fcntl@GLIBC_2.17");
+#endif
+
+#endif
+#endif
diff --git a/server/node_modules/sqlite3/src/macros.h b/server/node_modules/sqlite3/src/macros.h
new file mode 100644
index 0000000..3bcde83
--- /dev/null
+++ b/server/node_modules/sqlite3/src/macros.h
@@ -0,0 +1,207 @@
+#ifndef NODE_SQLITE3_SRC_MACROS_H
+#define NODE_SQLITE3_SRC_MACROS_H
+
+const char* sqlite_code_string(int code);
+const char* sqlite_authorizer_string(int type);
+#include <vector>
+
+// TODO: better way to work around StringConcat?
+#include <napi.h>
+inline Napi::String StringConcat(Napi::Value str1, Napi::Value str2) {
+  return Napi::String::New(str1.Env(), str1.As<Napi::String>().Utf8Value() +
+                    str2.As<Napi::String>().Utf8Value() );
+}
+
+// A Napi substitute IsInt32()
+inline bool OtherIsInt(Napi::Number source) {
+    double orig_val = source.DoubleValue();
+    double int_val = static_cast<double>(source.Int32Value());
+    if (orig_val == int_val) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+#define IS_FUNCTION(cb) \
+    !cb.IsUndefined() && cb.IsFunction()
+
+#define REQUIRE_ARGUMENTS(n)                                                   \
+    if (info.Length() < (n)) {                                                 \
+        Napi::TypeError::New(env, "Expected " #n "arguments").ThrowAsJavaScriptException(); \
+        return env.Null(); \
+    }
+
+
+#define REQUIRE_ARGUMENT_EXTERNAL(i, var)                                      \
+    if (info.Length() <= (i) || !info[i].IsExternal()) {                       \
+        Napi::TypeError::New(env, "Argument " #i " invalid").ThrowAsJavaScriptException(); \
+        return env.Null(); \
+    }                                                                          \
+    Napi::External var = info[i].As<Napi::External>();
+
+
+#define REQUIRE_ARGUMENT_FUNCTION(i, var)                                      \
+    if (info.Length() <= (i) || !info[i].IsFunction()) {                        \
+        Napi::TypeError::New(env, "Argument " #i " must be a function").ThrowAsJavaScriptException(); \
+        return env.Null(); \
+    }                                                                          \
+    Napi::Function var = info[i].As<Napi::Function>();
+
+
+#define REQUIRE_ARGUMENT_STRING(i, var)                                        \
+    if (info.Length() <= (i) || !info[i].IsString()) {                         \
+        Napi::TypeError::New(env, "Argument " #i " must be a string").ThrowAsJavaScriptException(); \
+        return env.Null(); \
+    }                                                                          \
+    std::string var = info[i].As<Napi::String>();
+
+#define REQUIRE_ARGUMENT_INTEGER(i, var)                                        \
+    if (info.Length() <= (i) || !info[i].IsNumber()) {                        \
+        Napi::TypeError::New(env, "Argument " #i " must be an integer").ThrowAsJavaScriptException(); \
+        return env.Null();        \
+    }                                                                          \
+    int var(info[i].As<Napi::Number>().Int32Value());
+
+#define OPTIONAL_ARGUMENT_FUNCTION(i, var)                                     \
+    Napi::Function var;                                                        \
+    if (info.Length() > i && !info[i].IsUndefined()) {                         \
+        if (!info[i].IsFunction()) {                                           \
+            Napi::TypeError::New(env, "Argument " #i " must be a function").ThrowAsJavaScriptException(); \
+            return env.Null(); \
+        }                                                                      \
+        var = info[i].As<Napi::Function>();                                    \
+    }
+
+
+#define OPTIONAL_ARGUMENT_INTEGER(i, var, default)                             \
+    int var;                                                                   \
+    if (info.Length() <= (i)) {                                                \
+        var = (default);                                                       \
+    }                                                                          \
+    else if (info[i].IsNumber()) {                                             \
+        if (OtherIsInt(info[i].As<Number>())) {                                \
+            var = info[i].As<Napi::Number>().Int32Value();                     \
+        }                                                                      \
+    }                                                                          \
+    else {                                                                     \
+        Napi::TypeError::New(env, "Argument " #i " must be an integer").ThrowAsJavaScriptException(); \
+        return env.Null(); \
+    }
+
+
+#define DEFINE_CONSTANT_INTEGER(target, constant, name)                        \
+    Napi::PropertyDescriptor::Value(#name, Napi::Number::New(env, constant),   \
+        static_cast<napi_property_attributes>(napi_enumerable | napi_configurable)),
+
+#define DEFINE_CONSTANT_STRING(target, constant, name)                         \
+    Napi::PropertyDescriptor::Value(#name, Napi::String::New(env, constant),   \
+        static_cast<napi_property_attributes>(napi_enumerable | napi_configurable)),
+
+#define EXCEPTION(msg, errno, name)                                            \
+    Napi::Value name = Napi::Error::New(env,                                   \
+        StringConcat(                                                          \
+            StringConcat(                                                      \
+                Napi::String::New(env, sqlite_code_string(errno)),             \
+                Napi::String::New(env, ": ")                                   \
+            ),                                                                 \
+            (msg)                                                              \
+        ).Utf8Value()                                                          \
+    ).Value();                                                                 \
+    Napi::Object name ##_obj = name.As<Napi::Object>();                        \
+    (name ##_obj).Set( Napi::String::New(env, "errno"), Napi::Number::New(env, errno)); \
+    (name ##_obj).Set( Napi::String::New(env, "code"),                         \
+        Napi::String::New(env, sqlite_code_string(errno)));
+
+
+#define EMIT_EVENT(obj, argc, argv)                                            \
+    TRY_CATCH_CALL((obj),                                                      \
+        (obj).Get("emit").As<Napi::Function>(),\
+        argc, argv                                                             \
+    );
+
+// The Mac OS compiler complains when argv is NULL unless we
+// first assign it to a locally defined variable.
+#define TRY_CATCH_CALL(context, callback, argc, argv, ...)                     \
+    Napi::Value* passed_argv = argv;\
+    std::vector<napi_value> args;\
+    if ((argc != 0) && (passed_argv != NULL)) {\
+      args.assign(passed_argv, passed_argv + argc);\
+    }\
+    Napi::Value res = (callback).Call(Napi::Value(context), args);             \
+    if (res.IsEmpty()) return __VA_ARGS__;
+
+#define WORK_DEFINITION(name)                                                  \
+    Napi::Value name(const Napi::CallbackInfo& info);                          \
+    static void Work_Begin##name(Baton* baton);                                \
+    static void Work_##name(napi_env env, void* data);                         \
+    static void Work_After##name(napi_env env, napi_status status, void* data);
+
+#ifdef DEBUG
+    #define ASSERT_STATUS() assert(status == 0);
+#else
+    #define ASSERT_STATUS() (void)status;
+#endif
+
+#define CREATE_WORK(name, workerFn, afterFn)                                    \
+    int status = napi_create_async_work(env, NULL, Napi::String::New(env, name),\
+                             workerFn, afterFn, baton, &baton->request);        \
+                                                                                \
+    ASSERT_STATUS();                                                            \
+    napi_queue_async_work(env, baton->request);
+
+#define STATEMENT_BEGIN(type)                                                  \
+    assert(baton);                                                             \
+    assert(baton->stmt);                                                       \
+    assert(!baton->stmt->locked);                                              \
+    assert(!baton->stmt->finalized);                                           \
+    assert(baton->stmt->prepared);                                             \
+    baton->stmt->locked = true;                                                \
+    baton->stmt->db->pending++;                                                \
+    auto env = baton->stmt->Env();                                             \
+    CREATE_WORK("sqlite3.Statement."#type, Work_##type, Work_After##type);
+
+#define STATEMENT_INIT(type)                                                   \
+    type* baton = static_cast<type*>(data);                                    \
+    Statement* stmt = baton->stmt;
+
+#define STATEMENT_MUTEX(name) \
+    if (!stmt->db->_handle) { \
+        stmt->status = SQLITE_MISUSE; \
+        stmt->message = "Database handle is closed"; \
+        return; \
+    } \
+    sqlite3_mutex* name = sqlite3_db_mutex(stmt->db->_handle);
+
+#define STATEMENT_END()                                                        \
+    assert(stmt->locked);                                                      \
+    assert(stmt->db->pending);                                                 \
+    stmt->locked = false;                                                      \
+    stmt->db->pending--;                                                       \
+    stmt->Process();                                                           \
+    stmt->db->Process();
+
+#define BACKUP_BEGIN(type)                                                     \
+    assert(baton);                                                             \
+    assert(baton->backup);                                                     \
+    assert(!baton->backup->locked);                                            \
+    assert(!baton->backup->finished);                                          \
+    assert(baton->backup->inited);                                             \
+    baton->backup->locked = true;                                              \
+    baton->backup->db->pending++;                                              \
+    auto env = baton->backup->Env();                                           \
+    CREATE_WORK("sqlite3.Backup."#type, Work_##type, Work_After##type);
+
+#define BACKUP_INIT(type)                                                      \
+    type* baton = static_cast<type*>(data);                                    \
+    Backup* backup = baton->backup;
+
+#define BACKUP_END()                                                           \
+    assert(backup->locked);                                                    \
+    assert(backup->db->pending);                                               \
+    backup->locked = false;                                                    \
+    backup->db->pending--;                                                     \
+    backup->Process();                                                         \
+    backup->db->Process();
+
+#endif
\ No newline at end of file
diff --git a/server/node_modules/sqlite3/src/node_sqlite3.cc b/server/node_modules/sqlite3/src/node_sqlite3.cc
new file mode 100644
index 0000000..6f47a68
--- /dev/null
+++ b/server/node_modules/sqlite3/src/node_sqlite3.cc
@@ -0,0 +1,128 @@
+#include <stdint.h>
+#include <sstream>
+#include <cstring>
+#include <string>
+#include <sqlite3.h>
+
+#include "macros.h"
+#include "database.h"
+#include "statement.h"
+#include "backup.h"
+
+using namespace node_sqlite3;
+
+namespace {
+
+Napi::Object RegisterModule(Napi::Env env, Napi::Object exports) {
+    Napi::HandleScope scope(env);
+
+    Database::Init(env, exports);
+    Statement::Init(env, exports);
+    Backup::Init(env, exports);
+
+    exports.DefineProperties({
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_OPEN_READONLY, OPEN_READONLY)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_OPEN_READWRITE, OPEN_READWRITE)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_OPEN_CREATE, OPEN_CREATE)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_OPEN_FULLMUTEX, OPEN_FULLMUTEX)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_OPEN_URI, OPEN_URI)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_OPEN_SHAREDCACHE, OPEN_SHAREDCACHE)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_OPEN_PRIVATECACHE, OPEN_PRIVATECACHE)
+        DEFINE_CONSTANT_STRING(exports, SQLITE_VERSION, VERSION)
+#ifdef SQLITE_SOURCE_ID
+        DEFINE_CONSTANT_STRING(exports, SQLITE_SOURCE_ID, SOURCE_ID)
+#endif
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_VERSION_NUMBER, VERSION_NUMBER)
+
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_OK, OK)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_ERROR, ERROR)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_INTERNAL, INTERNAL)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_PERM, PERM)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_ABORT, ABORT)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_BUSY, BUSY)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LOCKED, LOCKED)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_NOMEM, NOMEM)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_READONLY, READONLY)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_INTERRUPT, INTERRUPT)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_IOERR, IOERR)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_CORRUPT, CORRUPT)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_NOTFOUND, NOTFOUND)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_FULL, FULL)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_CANTOPEN, CANTOPEN)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_PROTOCOL, PROTOCOL)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_EMPTY, EMPTY)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_SCHEMA, SCHEMA)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_TOOBIG, TOOBIG)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_CONSTRAINT, CONSTRAINT)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_MISMATCH, MISMATCH)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_MISUSE, MISUSE)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_NOLFS, NOLFS)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_AUTH, AUTH)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_FORMAT, FORMAT)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_RANGE, RANGE)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_NOTADB, NOTADB)
+
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_LENGTH, LIMIT_LENGTH)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_SQL_LENGTH, LIMIT_SQL_LENGTH)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_COLUMN, LIMIT_COLUMN)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_EXPR_DEPTH, LIMIT_EXPR_DEPTH)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_COMPOUND_SELECT, LIMIT_COMPOUND_SELECT)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_VDBE_OP, LIMIT_VDBE_OP)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_FUNCTION_ARG, LIMIT_FUNCTION_ARG)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_ATTACHED, LIMIT_ATTACHED)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_LIKE_PATTERN_LENGTH, LIMIT_LIKE_PATTERN_LENGTH)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_VARIABLE_NUMBER, LIMIT_VARIABLE_NUMBER)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_TRIGGER_DEPTH, LIMIT_TRIGGER_DEPTH)
+        DEFINE_CONSTANT_INTEGER(exports, SQLITE_LIMIT_WORKER_THREADS, LIMIT_WORKER_THREADS)
+    });
+
+    return exports;
+}
+
+}
+
+const char* sqlite_code_string(int code) {
+    switch (code) {
+        case SQLITE_OK:         return "SQLITE_OK";
+        case SQLITE_ERROR:      return "SQLITE_ERROR";
+        case SQLITE_INTERNAL:   return "SQLITE_INTERNAL";
+        case SQLITE_PERM:       return "SQLITE_PERM";
+        case SQLITE_ABORT:      return "SQLITE_ABORT";
+        case SQLITE_BUSY:       return "SQLITE_BUSY";
+        case SQLITE_LOCKED:     return "SQLITE_LOCKED";
+        case SQLITE_NOMEM:      return "SQLITE_NOMEM";
+        case SQLITE_READONLY:   return "SQLITE_READONLY";
+        case SQLITE_INTERRUPT:  return "SQLITE_INTERRUPT";
+        case SQLITE_IOERR:      return "SQLITE_IOERR";
+        case SQLITE_CORRUPT:    return "SQLITE_CORRUPT";
+        case SQLITE_NOTFOUND:   return "SQLITE_NOTFOUND";
+        case SQLITE_FULL:       return "SQLITE_FULL";
+        case SQLITE_CANTOPEN:   return "SQLITE_CANTOPEN";
+        case SQLITE_PROTOCOL:   return "SQLITE_PROTOCOL";
+        case SQLITE_EMPTY:      return "SQLITE_EMPTY";
+        case SQLITE_SCHEMA:     return "SQLITE_SCHEMA";
+        case SQLITE_TOOBIG:     return "SQLITE_TOOBIG";
+        case SQLITE_CONSTRAINT: return "SQLITE_CONSTRAINT";
+        case SQLITE_MISMATCH:   return "SQLITE_MISMATCH";
+        case SQLITE_MISUSE:     return "SQLITE_MISUSE";
+        case SQLITE_NOLFS:      return "SQLITE_NOLFS";
+        case SQLITE_AUTH:       return "SQLITE_AUTH";
+        case SQLITE_FORMAT:     return "SQLITE_FORMAT";
+        case SQLITE_RANGE:      return "SQLITE_RANGE";
+        case SQLITE_NOTADB:     return "SQLITE_NOTADB";
+        case SQLITE_ROW:        return "SQLITE_ROW";
+        case SQLITE_DONE:       return "SQLITE_DONE";
+        default:                return "UNKNOWN";
+    }
+}
+
+const char* sqlite_authorizer_string(int type) {
+    switch (type) {
+        case SQLITE_INSERT:     return "insert";
+        case SQLITE_UPDATE:     return "update";
+        case SQLITE_DELETE:     return "delete";
+        default:                return "";
+    }
+}
+
+NODE_API_MODULE(node_sqlite3, RegisterModule)
diff --git a/server/node_modules/sqlite3/src/statement.cc b/server/node_modules/sqlite3/src/statement.cc
new file mode 100644
index 0000000..fc49b90
--- /dev/null
+++ b/server/node_modules/sqlite3/src/statement.cc
@@ -0,0 +1,939 @@
+#include <cstring>
+#include <napi.h>
+#include <uv.h>
+
+#include "macros.h"
+#include "database.h"
+#include "statement.h"
+
+using namespace node_sqlite3;
+
+Napi::Object Statement::Init(Napi::Env env, Napi::Object exports) {
+    Napi::HandleScope scope(env);
+
+    // declare napi_default_method here as it is only available in Node v14.12.0+
+    auto napi_default_method = static_cast<napi_property_attributes>(napi_writable | napi_configurable);
+
+    auto t = DefineClass(env, "Statement", {
+      InstanceMethod("bind", &Statement::Bind, napi_default_method),
+      InstanceMethod("get", &Statement::Get, napi_default_method),
+      InstanceMethod("run", &Statement::Run, napi_default_method),
+      InstanceMethod("all", &Statement::All, napi_default_method),
+      InstanceMethod("each", &Statement::Each, napi_default_method),
+      InstanceMethod("reset", &Statement::Reset, napi_default_method),
+      InstanceMethod("finalize", &Statement::Finalize_, napi_default_method),
+    });
+
+    exports.Set("Statement", t);
+    return exports;
+}
+
+// A Napi InstanceOf for Javascript Objects "Date" and "RegExp"
+bool OtherInstanceOf(Napi::Object source, const char* object_type) {
+    if (strncmp(object_type, "Date", 4) == 0) {
+        return source.InstanceOf(source.Env().Global().Get("Date").As<Function>());
+    } else if (strncmp(object_type, "RegExp", 6) == 0) {
+        return source.InstanceOf(source.Env().Global().Get("RegExp").As<Function>());
+    }
+
+    return false;
+}
+
+void Statement::Process() {
+    if (finalized && !queue.empty()) {
+        return CleanQueue();
+    }
+
+    while (prepared && !locked && !queue.empty()) {
+        auto call = std::unique_ptr<Call>(queue.front());
+        queue.pop();
+
+        call->callback(call->baton);
+    }
+}
+
+void Statement::Schedule(Work_Callback callback, Baton* baton) {
+    if (finalized) {
+        queue.emplace(new Call(callback, baton));
+        CleanQueue();
+    }
+    else if (!prepared || locked) {
+        queue.emplace(new Call(callback, baton));
+    }
+    else {
+        callback(baton);
+    }
+}
+
+template <class T> void Statement::Error(T* baton) {
+    Statement* stmt = baton->stmt;
+
+    auto env = stmt->Env();
+    Napi::HandleScope scope(env);
+
+    // Fail hard on logic errors.
+    assert(stmt->status != 0);
+    EXCEPTION(Napi::String::New(env, stmt->message.c_str()), stmt->status, exception);
+
+    Napi::Function cb = baton->callback.Value();
+
+    if (IS_FUNCTION(cb)) {
+        Napi::Value argv[] = { exception };
+        TRY_CATCH_CALL(stmt->Value(), cb, 1, argv);
+    }
+    else {
+        Napi::Value argv[] = { Napi::String::New(env, "error"), exception };
+        EMIT_EVENT(stmt->Value(), 2, argv);
+    }
+}
+
+// { Database db, String sql, Array params, Function callback }
+Statement::Statement(const Napi::CallbackInfo& info) : Napi::ObjectWrap<Statement>(info) {
+    auto env = info.Env();
+    int length = info.Length();
+
+    if (length <= 0 || !Database::HasInstance(info[0])) {
+        Napi::TypeError::New(env, "Database object expected").ThrowAsJavaScriptException();
+        return;
+    }
+    else if (length <= 1 || !info[1].IsString()) {
+        Napi::TypeError::New(env, "SQL query expected").ThrowAsJavaScriptException();
+        return;
+    }
+    else if (length > 2 && !info[2].IsUndefined() && !info[2].IsFunction()) {
+        Napi::TypeError::New(env, "Callback expected").ThrowAsJavaScriptException();
+        return;
+    }
+
+    this->db = Napi::ObjectWrap<Database>::Unwrap(info[0].As<Napi::Object>());
+    this->db->Ref();
+
+    auto sql = info[1].As<Napi::String>();
+
+    info.This().As<Napi::Object>().DefineProperty(Napi::PropertyDescriptor::Value("sql", sql, napi_default));
+
+
+    Statement* stmt = this;
+
+    auto* baton = new PrepareBaton(this->db, info[2].As<Napi::Function>(), stmt);
+    baton->sql = std::string(sql.As<Napi::String>().Utf8Value().c_str());
+    this->db->Schedule(Work_BeginPrepare, baton);
+}
+
+void Statement::Work_BeginPrepare(Database::Baton* baton) {
+    assert(baton->db->open);
+    baton->db->pending++;
+
+    auto env = baton->db->Env();
+    CREATE_WORK("sqlite3.Statement.Prepare", Work_Prepare, Work_AfterPrepare);
+}
+
+void Statement::Work_Prepare(napi_env e, void* data) {
+    STATEMENT_INIT(PrepareBaton);
+
+    // In case preparing fails, we use a mutex to make sure we get the associated
+    // error message.
+    STATEMENT_MUTEX(mtx);
+    sqlite3_mutex_enter(mtx);
+
+    stmt->status = sqlite3_prepare_v2(
+        baton->db->_handle,
+        baton->sql.c_str(),
+        baton->sql.size(),
+        &stmt->_handle,
+        NULL
+    );
+
+    if (stmt->status != SQLITE_OK) {
+        stmt->message = std::string(sqlite3_errmsg(baton->db->_handle));
+        stmt->_handle = NULL;
+    }
+
+    sqlite3_mutex_leave(mtx);
+}
+
+void Statement::Work_AfterPrepare(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<PrepareBaton> baton(static_cast<PrepareBaton*>(data));
+    auto* stmt = baton->stmt;
+
+    auto env = stmt->Env();
+    Napi::HandleScope scope(env);
+
+    if (stmt->status != SQLITE_OK) {
+        Error(baton.get());
+        stmt->Finalize_();
+    }
+    else {
+        stmt->prepared = true;
+        if (!baton->callback.IsEmpty() && baton->callback.Value().IsFunction()) {
+            Napi::Function cb = baton->callback.Value();
+            Napi::Value argv[] = { env.Null() };
+            TRY_CATCH_CALL(stmt->Value(), cb, 1, argv);
+        }
+    }
+
+    STATEMENT_END();
+}
+
+template <class T> std::unique_ptr<Values::Field>
+                   Statement::BindParameter(const Napi::Value source, T pos) {
+    if (source.IsString()) {
+        std::string val = source.As<Napi::String>().Utf8Value();
+        return std::make_unique<Values::Text>(pos, val.length(), val.c_str());
+    }
+    else if (OtherInstanceOf(source.As<Object>(), "RegExp")) {
+        std::string val = source.ToString().Utf8Value();
+        return std::make_unique<Values::Text>(pos, val.length(), val.c_str());
+    }
+    else if (source.IsNumber()) {
+        if (OtherIsInt(source.As<Napi::Number>())) {
+            return std::make_unique<Values::Integer>(pos, source.As<Napi::Number>().Int32Value());
+        } else {
+            return std::make_unique<Values::Float>(pos, source.As<Napi::Number>().DoubleValue());
+        }
+    }
+    else if (source.IsBoolean()) {
+        return std::make_unique<Values::Integer>(pos, source.As<Napi::Boolean>().Value() ? 1 : 0);
+    }
+    else if (source.IsNull()) {
+        return std::make_unique<Values::Null>(pos);
+    }
+    else if (source.IsBuffer()) {
+        Napi::Buffer<char> buffer = source.As<Napi::Buffer<char>>();
+        return std::make_unique<Values::Blob>(pos, buffer.Length(), buffer.Data());
+    }
+    else if (OtherInstanceOf(source.As<Object>(), "Date")) {
+        return std::make_unique<Values::Float>(pos, source.ToNumber().DoubleValue());
+    }
+    else if (source.IsObject()) {
+        auto napiVal = Napi::String::New(source.Env(), "[object Object]");
+        // Check whether toString returned a value that is not undefined.
+        if(napiVal.Type() == 0) {
+            return NULL;
+        }
+
+        std::string val = napiVal.Utf8Value();
+        return std::make_unique<Values::Text>(pos, val.length(), val.c_str());
+    }
+    else {
+        return NULL;
+    }
+}
+
+template <class T> T* Statement::Bind(const Napi::CallbackInfo& info, int start, int last) {
+    auto env = info.Env();
+    Napi::HandleScope scope(env);
+
+    if (last < 0) last = info.Length();
+    Napi::Function callback;
+    if (last > start && info[last - 1].IsFunction()) {
+        callback = info[last - 1].As<Napi::Function>();
+        last--;
+    }
+
+    auto *baton = new T(this, callback);
+
+    if (start < last) {
+        if (info[start].IsArray()) {
+            auto array = info[start].As<Napi::Array>();
+            int length = array.Length();
+            // Note: bind parameters start with 1.
+            for (int i = 0, pos = 1; i < length; i++, pos++) {
+                baton->parameters.emplace_back(BindParameter((array).Get(i), i + 1));
+            }
+        }
+        else if (!info[start].IsObject() || OtherInstanceOf(info[start].As<Object>(), "RegExp") 
+                || OtherInstanceOf(info[start].As<Object>(), "Date") || info[start].IsBuffer()) {
+            // Parameters directly in array.
+            // Note: bind parameters start with 1.
+            for (int i = start, pos = 1; i < last; i++, pos++) {
+                baton->parameters.emplace_back(BindParameter(info[i], pos));
+            }
+        }
+        else if (info[start].IsObject()) {
+            auto object = info[start].As<Napi::Object>();
+            auto array = object.GetPropertyNames();
+            int length = array.Length();
+            for (int i = 0; i < length; i++) {
+                Napi::Value name = (array).Get(i);
+                Napi::Number num = name.ToNumber();
+
+                if (num.Int32Value() == num.DoubleValue()) {
+                    baton->parameters.emplace_back(
+                        BindParameter((object).Get(name), num.Int32Value()));
+                }
+                else {
+                    baton->parameters.emplace_back(BindParameter((object).Get(name),
+                        name.As<Napi::String>().Utf8Value().c_str()));
+                }
+            }
+        }
+        else {
+            return NULL;
+        }
+    }
+
+    return baton;
+}
+
+bool Statement::Bind(const Parameters & parameters) {
+    if (parameters.empty()) {
+        return true;
+    }
+
+    sqlite3_reset(_handle);
+    sqlite3_clear_bindings(_handle);
+
+    for (auto& field : parameters) {
+        if (field == NULL)
+            continue;
+
+        unsigned int pos;
+        if (field->index > 0) {
+            pos = field->index;
+        }
+        else {
+            pos = sqlite3_bind_parameter_index(_handle, field->name.c_str());
+        }
+
+        switch (field->type) {
+            case SQLITE_INTEGER: {
+                status = sqlite3_bind_int(_handle, pos,
+                    (static_cast<Values::Integer*>(field.get()))->value);
+            } break;
+            case SQLITE_FLOAT: {
+                status = sqlite3_bind_double(_handle, pos,
+                    (static_cast<Values::Float*>(field.get()))->value);
+            } break;
+            case SQLITE_TEXT: {
+                status = sqlite3_bind_text(_handle, pos,
+                    (static_cast<Values::Text*>(field.get()))->value.c_str(),
+                    (static_cast<Values::Text*>(field.get()))->value.size(), SQLITE_TRANSIENT);
+            } break;
+            case SQLITE_BLOB: {
+                status = sqlite3_bind_blob(_handle, pos,
+                    (static_cast<Values::Blob*>(field.get()))->value,
+                    (static_cast<Values::Blob*>(field.get()))->length, SQLITE_TRANSIENT);
+            } break;
+            case SQLITE_NULL: {
+                status = sqlite3_bind_null(_handle, pos);
+            } break;
+        }
+
+            if (status != SQLITE_OK) {
+                message = std::string(sqlite3_errmsg(db->_handle));
+                return false;
+            }
+        }
+
+    return true;
+}
+
+Napi::Value Statement::Bind(const Napi::CallbackInfo& info) {
+    auto env = info.Env();
+    Statement* stmt = this;
+
+    auto baton = stmt->Bind<Baton>(info);
+    if (baton == NULL) {
+        Napi::TypeError::New(env, "Data type is not supported").ThrowAsJavaScriptException();
+        return env.Null();
+    }
+    else {
+        stmt->Schedule(Work_BeginBind, baton);
+        return info.This();
+    }
+}
+
+void Statement::Work_BeginBind(Baton* baton) {
+    STATEMENT_BEGIN(Bind);
+}
+
+void Statement::Work_Bind(napi_env e, void* data) {
+    STATEMENT_INIT(Baton);
+
+    STATEMENT_MUTEX(mtx);
+    sqlite3_mutex_enter(mtx);
+    stmt->Bind(baton->parameters);
+    sqlite3_mutex_leave(mtx);
+}
+
+void Statement::Work_AfterBind(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<Baton> baton(static_cast<Baton*>(data));
+    auto* stmt = baton->stmt;
+
+    auto env = stmt->Env();
+    Napi::HandleScope scope(env);
+
+    if (stmt->status != SQLITE_OK) {
+        Error(baton.get());
+    }
+    else {
+        // Fire callbacks.
+        Napi::Function cb = baton->callback.Value();
+        if (IS_FUNCTION(cb)) {
+            Napi::Value argv[] = { env.Null() };
+            TRY_CATCH_CALL(stmt->Value(), cb, 1, argv);
+        }
+    }
+
+    STATEMENT_END();
+}
+
+
+
+Napi::Value Statement::Get(const Napi::CallbackInfo& info) {
+    auto env = info.Env();
+    Statement* stmt = this;
+
+    Baton* baton = stmt->Bind<RowBaton>(info);
+    if (baton == NULL) {
+        Napi::Error::New(env, "Data type is not supported").ThrowAsJavaScriptException();
+        return env.Null();
+    }
+    else {
+        stmt->Schedule(Work_BeginGet, baton);
+        return info.This();
+    }
+}
+
+void Statement::Work_BeginGet(Baton* baton) {
+    STATEMENT_BEGIN(Get);
+}
+
+void Statement::Work_Get(napi_env e, void* data) {
+    STATEMENT_INIT(RowBaton);
+
+    if (stmt->status != SQLITE_DONE || baton->parameters.size()) {
+        STATEMENT_MUTEX(mtx);
+        sqlite3_mutex_enter(mtx);
+
+        if (stmt->Bind(baton->parameters)) {
+            stmt->status = sqlite3_step(stmt->_handle);
+
+            if (!(stmt->status == SQLITE_ROW || stmt->status == SQLITE_DONE)) {
+                stmt->message = std::string(sqlite3_errmsg(stmt->db->_handle));
+            }
+        }
+
+        sqlite3_mutex_leave(mtx);
+
+        if (stmt->status == SQLITE_ROW) {
+            // Acquire one result row before returning.
+            GetRow(&baton->row, stmt->_handle);
+        }
+    }
+}
+
+void Statement::Work_AfterGet(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<RowBaton> baton(static_cast<RowBaton*>(data));
+    auto* stmt = baton->stmt;
+
+    auto env = stmt->Env();
+    Napi::HandleScope scope(env);
+
+    if (stmt->status != SQLITE_ROW && stmt->status != SQLITE_DONE) {
+        Error(baton.get());
+    }
+    else {
+        // Fire callbacks.
+        Napi::Function cb = baton->callback.Value();
+        if (IS_FUNCTION(cb)) {
+            if (stmt->status == SQLITE_ROW) {
+                // Create the result array from the data we acquired.
+                Napi::Value argv[] = { env.Null(), RowToJS(env, &baton->row) };
+                TRY_CATCH_CALL(stmt->Value(), cb, 2, argv);
+            }
+            else {
+                Napi::Value argv[] = { env.Null() };
+                TRY_CATCH_CALL(stmt->Value(), cb, 1, argv);
+            }
+        }
+    }
+
+    STATEMENT_END();
+}
+
+Napi::Value Statement::Run(const Napi::CallbackInfo& info) {
+    auto env = info.Env();
+    Statement* stmt = this;
+
+    Baton* baton = stmt->Bind<RunBaton>(info);
+    if (baton == NULL) {
+        Napi::Error::New(env, "Data type is not supported").ThrowAsJavaScriptException();
+        return env.Null();
+    }
+    else {
+        stmt->Schedule(Work_BeginRun, baton);
+        return info.This();
+    }
+}
+
+void Statement::Work_BeginRun(Baton* baton) {
+    STATEMENT_BEGIN(Run);
+}
+
+void Statement::Work_Run(napi_env e, void* data) {
+    STATEMENT_INIT(RunBaton);
+
+    STATEMENT_MUTEX(mtx);
+    sqlite3_mutex_enter(mtx);
+
+    // Make sure that we also reset when there are no parameters.
+    if (!baton->parameters.size()) {
+        sqlite3_reset(stmt->_handle);
+    }
+
+    if (stmt->Bind(baton->parameters)) {
+        stmt->status = sqlite3_step(stmt->_handle);
+
+        if (!(stmt->status == SQLITE_ROW || stmt->status == SQLITE_DONE)) {
+            stmt->message = std::string(sqlite3_errmsg(stmt->db->_handle));
+        }
+        else {
+            baton->inserted_id = sqlite3_last_insert_rowid(stmt->db->_handle);
+            baton->changes = sqlite3_changes(stmt->db->_handle);
+        }
+    }
+
+    sqlite3_mutex_leave(mtx);
+}
+
+void Statement::Work_AfterRun(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<RunBaton> baton(static_cast<RunBaton*>(data));
+    auto* stmt = baton->stmt;
+
+    auto env = stmt->Env();
+    Napi::HandleScope scope(env);
+
+    if (stmt->status != SQLITE_ROW && stmt->status != SQLITE_DONE) {
+        Error(baton.get());
+    }
+    else {
+        // Fire callbacks.
+        Napi::Function cb = baton->callback.Value();
+        if (IS_FUNCTION(cb)) {
+            (stmt->Value()).Set(Napi::String::New(env, "lastID"), Napi::Number::New(env, baton->inserted_id));
+            (stmt->Value()).Set( Napi::String::New(env, "changes"), Napi::Number::New(env, baton->changes));
+
+            Napi::Value argv[] = { env.Null() };
+            TRY_CATCH_CALL(stmt->Value(), cb, 1, argv);
+        }
+    }
+
+    STATEMENT_END();
+}
+
+Napi::Value Statement::All(const Napi::CallbackInfo& info) {
+    auto env = info.Env();
+    Statement* stmt = this;
+
+    Baton* baton = stmt->Bind<RowsBaton>(info);
+    if (baton == NULL) {
+        Napi::Error::New(env, "Data type is not supported").ThrowAsJavaScriptException();
+        return env.Null();
+    }
+    else {
+        stmt->Schedule(Work_BeginAll, baton);
+        return info.This();
+    }
+}
+
+void Statement::Work_BeginAll(Baton* baton) {
+    STATEMENT_BEGIN(All);
+}
+
+void Statement::Work_All(napi_env e, void* data) {
+    STATEMENT_INIT(RowsBaton);
+
+    STATEMENT_MUTEX(mtx);
+    sqlite3_mutex_enter(mtx);
+
+    // Make sure that we also reset when there are no parameters.
+    if (!baton->parameters.size()) {
+        sqlite3_reset(stmt->_handle);
+    }
+
+    if (stmt->Bind(baton->parameters)) {
+        while ((stmt->status = sqlite3_step(stmt->_handle)) == SQLITE_ROW) {
+            auto row = std::make_unique<Row>();
+            GetRow(row.get(), stmt->_handle);
+            baton->rows.emplace_back(std::move(row));
+        }
+
+        if (stmt->status != SQLITE_DONE) {
+            stmt->message = std::string(sqlite3_errmsg(stmt->db->_handle));
+        }
+    }
+
+    sqlite3_mutex_leave(mtx);
+}
+
+void Statement::Work_AfterAll(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<RowsBaton> baton(static_cast<RowsBaton*>(data));
+    auto* stmt = baton->stmt;
+
+    auto env = stmt->Env();
+    Napi::HandleScope scope(env);
+
+    if (stmt->status != SQLITE_DONE) {
+        Error(baton.get());
+    }
+    else {
+        // Fire callbacks.
+        Napi::Function cb = baton->callback.Value();
+        if (IS_FUNCTION(cb)) {
+            if (baton->rows.size()) {
+                // Create the result array from the data we acquired.
+                Napi::Array result(Napi::Array::New(env, baton->rows.size()));
+                auto it = static_cast<Rows::const_iterator>(baton->rows.begin());
+                decltype(it) end = baton->rows.end();
+                for (int i = 0; it < end; ++it, i++) {
+                    (result).Set(i, RowToJS(env, it->get()));
+                }
+
+                Napi::Value argv[] = { env.Null(), result };
+                TRY_CATCH_CALL(stmt->Value(), cb, 2, argv);
+            }
+            else {
+                // There were no result rows.
+                Napi::Value argv[] = {
+                    env.Null(),
+                    Napi::Array::New(env, 0)
+                };
+                TRY_CATCH_CALL(stmt->Value(), cb, 2, argv);
+            }
+        }
+    }
+
+    STATEMENT_END();
+}
+
+Napi::Value Statement::Each(const Napi::CallbackInfo& info) {
+    auto env = info.Env();
+    Statement* stmt = this;
+
+    int last = info.Length();
+
+    Napi::Function completed;
+    if (last >= 2 && info[last - 1].IsFunction() && info[last - 2].IsFunction()) {
+        completed = info[--last].As<Napi::Function>();
+    }
+
+    auto baton = stmt->Bind<EachBaton>(info, 0, last);
+    if (baton == NULL) {
+        Napi::Error::New(env, "Data type is not supported").ThrowAsJavaScriptException();
+        return env.Null();
+    }
+    else {
+        baton->completed.Reset(completed, 1);
+        stmt->Schedule(Work_BeginEach, baton);
+        return info.This();
+    }
+}
+
+void Statement::Work_BeginEach(Baton* baton) {
+    // Only create the Async object when we're actually going into
+    // the event loop. This prevents dangling events.
+    auto* each_baton = static_cast<EachBaton*>(baton);
+    each_baton->async = new Async(each_baton->stmt, reinterpret_cast<uv_async_cb>(AsyncEach));
+    each_baton->async->item_cb.Reset(each_baton->callback.Value(), 1);
+    each_baton->async->completed_cb.Reset(each_baton->completed.Value(), 1);
+
+    STATEMENT_BEGIN(Each);
+}
+
+void Statement::Work_Each(napi_env e, void* data) {
+    STATEMENT_INIT(EachBaton);
+
+    auto* async = baton->async;
+
+    STATEMENT_MUTEX(mtx);
+
+    // Make sure that we also reset when there are no parameters.
+    if (!baton->parameters.size()) {
+        sqlite3_reset(stmt->_handle);
+    }
+
+    if (stmt->Bind(baton->parameters)) {
+        while (true) {
+            sqlite3_mutex_enter(mtx);
+            stmt->status = sqlite3_step(stmt->_handle);
+            if (stmt->status == SQLITE_ROW) {
+                sqlite3_mutex_leave(mtx);
+                auto row = std::make_unique<Row>();
+                GetRow(row.get(), stmt->_handle);
+                NODE_SQLITE3_MUTEX_LOCK(&async->mutex)
+                async->data.emplace_back(std::move(row));
+                NODE_SQLITE3_MUTEX_UNLOCK(&async->mutex)
+
+                uv_async_send(&async->watcher);
+            }
+            else {
+                if (stmt->status != SQLITE_DONE) {
+                    stmt->message = std::string(sqlite3_errmsg(stmt->db->_handle));
+                }
+                sqlite3_mutex_leave(mtx);
+                break;
+            }
+        }
+    }
+
+    async->completed = true;
+    uv_async_send(&async->watcher);
+}
+
+void Statement::CloseCallback(uv_handle_t* handle) {
+    assert(handle != NULL);
+    assert(handle->data != NULL);
+    auto* async = static_cast<Async*>(handle->data);
+    delete async;
+}
+
+void Statement::AsyncEach(uv_async_t* handle) {
+    auto* async = static_cast<Async*>(handle->data);
+
+    auto env = async->stmt->Env();
+    Napi::HandleScope scope(env);
+
+    while (true) {
+        // Get the contents out of the data cache for us to process in the JS callback.
+        Rows rows;
+        NODE_SQLITE3_MUTEX_LOCK(&async->mutex)
+        rows.swap(async->data);
+        NODE_SQLITE3_MUTEX_UNLOCK(&async->mutex)
+
+        if (rows.empty()) {
+            break;
+        }
+
+        Napi::Function cb = async->item_cb.Value();
+        if (IS_FUNCTION(cb)) {
+            Napi::Value argv[2];
+            argv[0] = env.Null();
+
+            for(auto& row : rows) {
+                argv[1] = RowToJS(env,row.get());
+                async->retrieved++;
+                TRY_CATCH_CALL(async->stmt->Value(), cb, 2, argv);
+            }
+        }
+    }
+
+    Napi::Function cb = async->completed_cb.Value();
+    if (async->completed) {
+        if (!cb.IsEmpty() &&
+                cb.IsFunction()) {
+            Napi::Value argv[] = {
+                env.Null(),
+                Napi::Number::New(env, async->retrieved)
+            };
+            TRY_CATCH_CALL(async->stmt->Value(), cb, 2, argv);
+        }
+        uv_close(reinterpret_cast<uv_handle_t*>(handle), CloseCallback);
+    }
+}
+
+void Statement::Work_AfterEach(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<EachBaton> baton(static_cast<EachBaton*>(data));
+    auto* stmt = baton->stmt;
+
+    auto env = stmt->Env();
+    Napi::HandleScope scope(env);
+
+    if (stmt->status != SQLITE_DONE) {
+        Error(baton.get());
+    }
+
+    STATEMENT_END();
+}
+
+Napi::Value Statement::Reset(const Napi::CallbackInfo& info) {
+    auto env = info.Env();
+    Statement* stmt = this;
+
+    OPTIONAL_ARGUMENT_FUNCTION(0, callback);
+
+    auto* baton = new Baton(stmt, callback);
+    stmt->Schedule(Work_BeginReset, baton);
+
+    return info.This();
+}
+
+void Statement::Work_BeginReset(Baton* baton) {
+    STATEMENT_BEGIN(Reset);
+}
+
+void Statement::Work_Reset(napi_env e, void* data) {
+    STATEMENT_INIT(Baton);
+
+    sqlite3_reset(stmt->_handle);
+    stmt->status = SQLITE_OK;
+}
+
+void Statement::Work_AfterReset(napi_env e, napi_status status, void* data) {
+    std::unique_ptr<Baton> baton(static_cast<Baton*>(data));
+    auto* stmt = baton->stmt;
+
+    auto env = stmt->Env();
+    Napi::HandleScope scope(env);
+
+    // Fire callbacks.
+    Napi::Function cb = baton->callback.Value();
+    if (IS_FUNCTION(cb)) {
+        Napi::Value argv[] = { env.Null() };
+        TRY_CATCH_CALL(stmt->Value(), cb, 1, argv);
+    }
+
+    STATEMENT_END();
+}
+
+Napi::Value Statement::RowToJS(Napi::Env env, Row* row) {
+    Napi::EscapableHandleScope scope(env);
+
+    auto result = Napi::Object::New(env);
+
+    for (auto& field : *row) {
+
+        Napi::Value value;
+
+        switch (field->type) {
+            case SQLITE_INTEGER: {
+                value = Napi::Number::New(env, (static_cast<Values::Integer*>(field.get()))->value);
+            } break;
+            case SQLITE_FLOAT: {
+                value = Napi::Number::New(env, (static_cast<Values::Float*>(field.get()))->value);
+            } break;
+            case SQLITE_TEXT: {
+                value = Napi::String::New(env, (static_cast<Values::Text*>(field.get()))->value.c_str(), 
+                                               (static_cast<Values::Text*>(field.get()))->value.size());
+            } break;
+            case SQLITE_BLOB: {
+                value = Napi::Buffer<char>::Copy(env, (static_cast<Values::Blob*>(field.get()))->value, 
+                                                      (static_cast<Values::Blob*>(field.get()))->length);
+            } break;
+            case SQLITE_NULL: {
+                value = env.Null();
+            } break;
+        }
+
+        result.Set(field->name, value);
+    }
+
+    return scope.Escape(result);
+}
+
+void Statement::GetRow(Row* row, sqlite3_stmt* stmt) {
+    int cols = sqlite3_column_count(stmt);
+
+    for (int i = 0; i < cols; i++) {
+        int type = sqlite3_column_type(stmt, i);
+        const char* name = sqlite3_column_name(stmt, i);
+        if (name == NULL) {
+            assert(false);
+        }
+
+        switch (type) {
+            case SQLITE_INTEGER: {
+                row->emplace_back(std::make_unique<Values::Integer>(name, sqlite3_column_int64(stmt, i)));
+            }   break;
+            case SQLITE_FLOAT: {
+                row->emplace_back(std::make_unique<Values::Float>(name, sqlite3_column_double(stmt, i)));
+            }   break;
+            case SQLITE_TEXT: {
+                const char* text = (const char*)sqlite3_column_text(stmt, i);
+                int length = sqlite3_column_bytes(stmt, i);
+                row->emplace_back(std::make_unique<Values::Text>(name, length, text));
+            } break;
+            case SQLITE_BLOB: {
+                const void* blob = sqlite3_column_blob(stmt, i);
+                int length = sqlite3_column_bytes(stmt, i);
+                row->emplace_back(std::make_unique<Values::Blob>(name, length, blob));
+            }   break;
+            case SQLITE_NULL: {
+                row->emplace_back(std::make_unique<Values::Null>(name));
+            }   break;
+            default:
+                assert(false);
+        }
+    }
+}
+
+Napi::Value Statement::Finalize_(const Napi::CallbackInfo& info) {
+    auto env = info.Env();
+    Statement* stmt = this;
+    OPTIONAL_ARGUMENT_FUNCTION(0, callback);
+
+    auto *baton = new Baton(stmt, callback);
+    stmt->Schedule(Finalize_, baton);
+
+    return stmt->db->Value();
+}
+
+void Statement::Finalize_(Baton* b) {
+    auto baton = std::unique_ptr<Baton>(b);
+    auto env = baton->stmt->Env();
+    Napi::HandleScope scope(env);
+
+    baton->stmt->Finalize_();
+
+    // Fire callback in case there was one.
+    Napi::Function cb = baton->callback.Value();
+    if (IS_FUNCTION(cb)) {
+        TRY_CATCH_CALL(baton->stmt->Value(), cb, 0, NULL);
+    }
+}
+
+void Statement::Finalize_() {
+    assert(!finalized);
+    finalized = true;
+    CleanQueue();
+    // Finalize returns the status code of the last operation. We already fired
+    // error events in case those failed.
+    sqlite3_finalize(_handle);
+    _handle = NULL;
+    db->Unref();
+}
+
+void Statement::CleanQueue() {
+    auto env = this->Env();
+    Napi::HandleScope scope(env);
+
+    if (prepared && !queue.empty()) {
+        // This statement has already been prepared and is now finalized.
+        // Fire error for all remaining items in the queue.
+        EXCEPTION(Napi::String::New(env, "Statement is already finalized"), SQLITE_MISUSE, exception);
+        Napi::Value argv[] = { exception };
+        bool called = false;
+
+        // Clear out the queue so that this object can get GC'ed.
+        while (!queue.empty()) {
+            auto call = std::unique_ptr<Call>(queue.front());
+            queue.pop();
+
+            auto baton = std::unique_ptr<Baton>(call->baton);
+            Napi::Function cb = baton->callback.Value();
+
+            if (prepared && !cb.IsEmpty() &&
+                cb.IsFunction()) {
+                TRY_CATCH_CALL(Value(), cb, 1, argv);
+                called = true;
+            }
+        }
+
+        // When we couldn't call a callback function, emit an error on the
+        // Statement object.
+        if (!called) {
+            Napi::Value info[] = { Napi::String::New(env, "error"), exception };
+            EMIT_EVENT(Value(), 2, info);
+        }
+    }
+    else while (!queue.empty()) {
+        // Just delete all items in the queue; we already fired an event when
+        // preparing the statement failed.
+        auto call = std::unique_ptr<Call>(queue.front());
+        queue.pop();
+        // We don't call the actual callback, so we have to make sure that
+        // the baton gets destroyed.
+        delete call->baton;
+    }
+}
diff --git a/server/node_modules/sqlite3/src/statement.h b/server/node_modules/sqlite3/src/statement.h
new file mode 100644
index 0000000..c522c0f
--- /dev/null
+++ b/server/node_modules/sqlite3/src/statement.h
@@ -0,0 +1,244 @@
+#ifndef NODE_SQLITE3_SRC_STATEMENT_H
+#define NODE_SQLITE3_SRC_STATEMENT_H
+
+#include <cstdlib>
+#include <cstring>
+#include <string>
+#include <queue>
+#include <vector>
+#include <sqlite3.h>
+#include <napi.h>
+#include <uv.h>
+
+#include "database.h"
+#include "threading.h"
+
+using namespace Napi;
+
+namespace node_sqlite3 {
+
+namespace Values {
+    struct Field {
+        inline Field(unsigned short _index, unsigned short _type = SQLITE_NULL) :
+            type(_type), index(_index) {}
+        inline Field(const char* _name, unsigned short _type = SQLITE_NULL) :
+            type(_type), index(0), name(_name) {}
+
+        unsigned short type;
+        unsigned short index;
+        std::string name;
+
+        virtual ~Field() = default;
+    };
+
+    struct Integer : Field {
+        template <class T> inline Integer(T _name, int64_t val) :
+            Field(_name, SQLITE_INTEGER), value(val) {}
+        int64_t value;
+        virtual ~Integer() override = default;
+    };
+
+    struct Float : Field {
+        template <class T> inline Float(T _name, double val) :
+            Field(_name, SQLITE_FLOAT), value(val) {}
+        double value;
+        virtual ~Float() override = default;
+    };
+
+    struct Text : Field {
+        template <class T> inline Text(T _name, size_t len, const char* val) :
+            Field(_name, SQLITE_TEXT), value(val, len) {}
+        std::string value;
+        virtual ~Text() override = default;
+    };
+
+    struct Blob : Field {
+        template <class T> inline Blob(T _name, size_t len, const void* val) :
+                Field(_name, SQLITE_BLOB), length(len) {
+            value = new char[len];
+            assert(value != nullptr);
+            memcpy(value, val, len);
+        }
+        inline virtual ~Blob() override {
+            delete[] value;
+        }
+        int length;
+        char* value;
+    };
+
+    typedef Field Null;
+}
+
+typedef std::vector<std::unique_ptr<Values::Field> > Row;
+typedef std::vector<std::unique_ptr<Row> > Rows;
+typedef Row Parameters;
+
+
+
+class Statement : public Napi::ObjectWrap<Statement> {
+public:
+    static Napi::Object Init(Napi::Env env, Napi::Object exports);
+    static Napi::Value New(const Napi::CallbackInfo& info);
+
+    struct Baton {
+        napi_async_work request = NULL;
+        Statement* stmt;
+        Napi::FunctionReference callback;
+        Parameters parameters;
+
+        Baton(Statement* stmt_, Napi::Function cb_) : stmt(stmt_) {
+            stmt->Ref();
+            callback.Reset(cb_, 1);
+        }
+        virtual ~Baton() {
+            parameters.clear();
+            if (request) napi_delete_async_work(stmt->Env(), request);
+            stmt->Unref();
+            callback.Reset();
+        }
+    };
+
+    struct RowBaton : Baton {
+        RowBaton(Statement* stmt_, Napi::Function cb_) :
+            Baton(stmt_, cb_) {}
+        Row row;
+        virtual ~RowBaton() override = default;
+    };
+
+    struct RunBaton : Baton {
+        RunBaton(Statement* stmt_, Napi::Function cb_) :
+            Baton(stmt_, cb_), inserted_id(0), changes(0) {}
+        sqlite3_int64 inserted_id;
+        int changes;
+        virtual ~RunBaton() override = default;
+    };
+
+    struct RowsBaton : Baton {
+        RowsBaton(Statement* stmt_, Napi::Function cb_) :
+            Baton(stmt_, cb_) {}
+        Rows rows;
+        virtual ~RowsBaton() override = default;
+    };
+
+    struct Async;
+
+    struct EachBaton : Baton {
+        Napi::FunctionReference completed;
+        Async* async; // Isn't deleted when the baton is deleted.
+
+        EachBaton(Statement* stmt_, Napi::Function cb_) :
+            Baton(stmt_, cb_) {}
+        virtual ~EachBaton() override {
+            completed.Reset();
+        }
+    };
+
+    struct PrepareBaton : Database::Baton {
+        Statement* stmt;
+        std::string sql;
+        PrepareBaton(Database* db_, Napi::Function cb_, Statement* stmt_) :
+            Baton(db_, cb_), stmt(stmt_) {
+            stmt->Ref();
+        }
+        virtual ~PrepareBaton() override {
+            stmt->Unref();
+            if (!db->IsOpen() && db->IsLocked()) {
+                // The database handle was closed before the statement could be
+                // prepared.
+                stmt->Finalize_();
+            }
+        }
+    };
+
+    typedef void (*Work_Callback)(Baton* baton);
+
+    struct Call {
+        Call(Work_Callback cb_, Baton* baton_) : callback(cb_), baton(baton_) {};
+        Work_Callback callback;
+        Baton* baton;
+    };
+
+    struct Async {
+        uv_async_t watcher;
+        Statement* stmt;
+        Rows data;
+        NODE_SQLITE3_MUTEX_t;
+        bool completed;
+        int retrieved;
+
+        // Store the callbacks here because we don't have
+        // access to the baton in the async callback.
+        Napi::FunctionReference item_cb;
+        Napi::FunctionReference completed_cb;
+
+        Async(Statement* st, uv_async_cb async_cb) :
+                stmt(st), completed(false), retrieved(0) {
+            watcher.data = this;
+            NODE_SQLITE3_MUTEX_INIT
+            stmt->Ref();
+            uv_loop_t *loop;
+            napi_get_uv_event_loop(stmt->Env(), &loop);
+            uv_async_init(loop, &watcher, async_cb);
+        }
+
+        ~Async() {
+            stmt->Unref();
+            item_cb.Reset();
+            completed_cb.Reset();
+            NODE_SQLITE3_MUTEX_DESTROY
+        }
+    };
+
+    Statement(const Napi::CallbackInfo& info);
+
+    ~Statement() {
+        if (!finalized) Finalize_();
+    }
+
+    WORK_DEFINITION(Bind)
+    WORK_DEFINITION(Get)
+    WORK_DEFINITION(Run)
+    WORK_DEFINITION(All)
+    WORK_DEFINITION(Each)
+    WORK_DEFINITION(Reset)
+
+    Napi::Value Finalize_(const Napi::CallbackInfo& info);
+
+protected:
+    static void Work_BeginPrepare(Database::Baton* baton);
+    static void Work_Prepare(napi_env env, void* data);
+    static void Work_AfterPrepare(napi_env env, napi_status status, void* data);
+
+    static void AsyncEach(uv_async_t* handle);
+    static void CloseCallback(uv_handle_t* handle);
+
+    static void Finalize_(Baton* baton);
+    void Finalize_();
+
+    template <class T> inline std::unique_ptr<Values::Field> BindParameter(const Napi::Value source, T pos);
+    template <class T> T* Bind(const Napi::CallbackInfo& info, int start = 0, int end = -1);
+    bool Bind(const Parameters ¶meters);
+
+    static void GetRow(Row* row, sqlite3_stmt* stmt);
+    static Napi::Value RowToJS(Napi::Env env, Row* row);
+    void Schedule(Work_Callback callback, Baton* baton);
+    void Process();
+    void CleanQueue();
+    template <class T> static void Error(T* baton);
+
+protected:
+    Database* db;
+
+    sqlite3_stmt* _handle = NULL;
+    int status = SQLITE_OK;
+    bool prepared = false;
+    bool locked = true;
+    bool finalized = false;
+
+    std::queue<Call*> queue;
+    std::string message;
+};
+
+}
+
+#endif
diff --git a/server/node_modules/sqlite3/src/threading.h b/server/node_modules/sqlite3/src/threading.h
new file mode 100644
index 0000000..7c7139b
--- /dev/null
+++ b/server/node_modules/sqlite3/src/threading.h
@@ -0,0 +1,10 @@
+#ifndef NODE_SQLITE3_SRC_THREADING_H
+#define NODE_SQLITE3_SRC_THREADING_H
+
+#define NODE_SQLITE3_MUTEX_t uv_mutex_t mutex;
+#define NODE_SQLITE3_MUTEX_INIT uv_mutex_init(&mutex);
+#define NODE_SQLITE3_MUTEX_LOCK(m) uv_mutex_lock(m);
+#define NODE_SQLITE3_MUTEX_UNLOCK(m) uv_mutex_unlock(m);
+#define NODE_SQLITE3_MUTEX_DESTROY uv_mutex_destroy(&mutex);
+
+#endif // NODE_SQLITE3_SRC_THREADING_H
diff --git a/server/node_modules/ssri/CHANGELOG.md b/server/node_modules/ssri/CHANGELOG.md
new file mode 100644
index 0000000..3fea458
--- /dev/null
+++ b/server/node_modules/ssri/CHANGELOG.md
@@ -0,0 +1,355 @@
+# Changelog
+
+All notable changes to this project will be documented in this file. See [standard-version](https://github.com/conventional-changelog/standard-version) for commit guidelines.
+
+### [8.0.1](https://github.com/npm/ssri/compare/v8.0.0...v8.0.1) (2021-01-27)
+
+
+### Bug Fixes
+
+* simplify regex for strict mode, add tests ([76e2233](https://github.com/npm/ssri/commit/76e223317d971f19e4db8191865bdad5edee40d2))
+
+## [8.0.0](https://github.com/npm/ssri/compare/v7.1.0...v8.0.0) (2020-02-18)
+
+
+### ⚠ BREAKING CHANGES
+
+* SRI values with `../` in the algorithm name now throw
+as invalid (which they always probably should have!)
+* adds a new error that will be thrown.  Empty SRIs are
+no longer considered valid for checking, only when using integrityStream
+to calculate the SRI value.
+
+PR-URL: https://github.com/npm/ssri/pull/12
+Credit: @claudiahdz
+
+### Features
+
+* remove figgy-pudding ([0e78fd7](https://github.com/npm/ssri/commit/0e78fd7b754e2d098875eb4c57238709d96d7c27))
+
+
+### Bug Fixes
+
+* harden SRI parsing against ../ funny business ([4062735](https://github.com/npm/ssri/commit/4062735d1281941fd32ac4320b9f9965fcec278b))
+* IntegrityStream responds to mutating opts object mid-stream ([4a963e5](https://github.com/npm/ssri/commit/4a963e5982478c6b07f86848cdb72d142c765195))
+* throw null when sri is empty or bad ([a6811cb](https://github.com/npm/ssri/commit/a6811cba71e20ea1fdefa6e50c9ea3c67efc2500)), closes [#12](https://github.com/npm/ssri/issues/12)
+
+## [7.1.0](https://github.com/npm/ssri/compare/v7.0.1...v7.1.0) (2019-10-24)
+
+
+### Bug Fixes
+
+* Do not blow up if the opts object is mutated ([806e8c8](https://github.com/npm/ssri/commit/806e8c8))
+
+
+### Features
+
+* Add Integrity#merge method ([0572c1d](https://github.com/npm/ssri/commit/0572c1d)), closes [#4](https://github.com/npm/ssri/issues/4)
+
+### [7.0.1](https://github.com/npm/ssri/compare/v7.0.0...v7.0.1) (2019-09-30)
+
+## [7.0.0](https://github.com/npm/ssri/compare/v6.0.1...v7.0.0) (2019-09-18)
+
+
+### ⚠ BREAKING CHANGES
+
+* ssri no longer accepts a Promise option, and does not
+use, return, or rely on Bluebird promises.
+* drop support for Node.js v6.
+
+We knew this was coming, and the Stream changes are breaking anyway.
+May as well do this now.
+* **streams:** this replaces the Node.js stream with a Minipass
+stream.  See http://npm.im/minipass for documentation.
+
+### Bug Fixes
+
+* return super.write() return value ([55b055d](https://github.com/npm/ssri/commit/55b055d))
+
+
+* Use native promises only ([6d13165](https://github.com/npm/ssri/commit/6d13165))
+* update tap, standard, standard-version, travis ([2e54956](https://github.com/npm/ssri/commit/2e54956))
+* **streams:** replace transform streams with minipass ([363995e](https://github.com/npm/ssri/commit/363995e))
+
+<a name="6.0.1"></a>
+## [6.0.1](https://github.com/npm/ssri/compare/v6.0.0...v6.0.1) (2018-08-27)
+
+
+### Bug Fixes
+
+* **opts:** use figgy-pudding to specify consumed opts ([cf86553](https://github.com/npm/ssri/commit/cf86553))
+
+
+
+<a name="6.0.0"></a>
+# [6.0.0](https://github.com/npm/ssri/compare/v5.3.0...v6.0.0) (2018-04-09)
+
+
+### Bug Fixes
+
+* **docs:** minor typo ([b71ef17](https://github.com/npm/ssri/commit/b71ef17))
+
+
+### meta
+
+* drop support for node@4 ([d9bf359](https://github.com/npm/ssri/commit/d9bf359))
+
+
+### BREAKING CHANGES
+
+* node@4 is no longer supported
+
+
+
+<a name="5.3.0"></a>
+# [5.3.0](https://github.com/npm/ssri/compare/v5.2.4...v5.3.0) (2018-03-13)
+
+
+### Features
+
+* **checkData:** optionally throw when checkData fails ([bf26b84](https://github.com/npm/ssri/commit/bf26b84))
+
+
+
+<a name="5.2.4"></a>
+## [5.2.4](https://github.com/npm/ssri/compare/v5.2.3...v5.2.4) (2018-02-16)
+
+
+
+<a name="5.2.3"></a>
+## [5.2.3](https://github.com/npm/ssri/compare/v5.2.2...v5.2.3) (2018-02-16)
+
+
+### Bug Fixes
+
+* **hashes:** filter hash priority list by available hashes ([2fa30b8](https://github.com/npm/ssri/commit/2fa30b8))
+* **integrityStream:** dedupe algorithms to generate ([d56c654](https://github.com/npm/ssri/commit/d56c654))
+
+
+
+<a name="5.2.2"></a>
+## [5.2.2](https://github.com/npm/ssri/compare/v5.2.1...v5.2.2) (2018-02-14)
+
+
+### Bug Fixes
+
+* **security:** tweak strict SRI regex ([#10](https://github.com/npm/ssri/issues/10)) ([d0ebcdc](https://github.com/npm/ssri/commit/d0ebcdc))
+
+
+
+<a name="5.2.1"></a>
+## [5.2.1](https://github.com/npm/ssri/compare/v5.2.0...v5.2.1) (2018-02-06)
+
+
+
+<a name="5.2.0"></a>
+# [5.2.0](https://github.com/npm/ssri/compare/v5.1.0...v5.2.0) (2018-02-06)
+
+
+### Features
+
+* **match:** add integrity.match() ([3c49cc4](https://github.com/npm/ssri/commit/3c49cc4))
+
+
+
+<a name="5.1.0"></a>
+# [5.1.0](https://github.com/npm/ssri/compare/v5.0.0...v5.1.0) (2018-01-18)
+
+
+### Bug Fixes
+
+* **checkStream:** integrityStream now takes opts.integrity algos into account ([d262910](https://github.com/npm/ssri/commit/d262910))
+
+
+### Features
+
+* **sha3:** do some guesswork about upcoming sha3 ([7fdd9df](https://github.com/npm/ssri/commit/7fdd9df))
+
+
+
+<a name="5.0.0"></a>
+# [5.0.0](https://github.com/npm/ssri/compare/v4.1.6...v5.0.0) (2017-10-23)
+
+
+### Features
+
+* **license:** relicense to ISC (#9) ([c82983a](https://github.com/npm/ssri/commit/c82983a))
+
+
+### BREAKING CHANGES
+
+* **license:** the license has been changed from CC0-1.0 to ISC.
+
+
+
+<a name="4.1.6"></a>
+## [4.1.6](https://github.com/npm/ssri/compare/v4.1.5...v4.1.6) (2017-06-07)
+
+
+### Bug Fixes
+
+* **checkStream:** make sure to pass all opts through ([0b1bcbe](https://github.com/npm/ssri/commit/0b1bcbe))
+
+
+
+<a name="4.1.5"></a>
+## [4.1.5](https://github.com/npm/ssri/compare/v4.1.4...v4.1.5) (2017-06-05)
+
+
+### Bug Fixes
+
+* **integrityStream:** stop crashing if opts.algorithms and opts.integrity have an algo mismatch ([fb1293e](https://github.com/npm/ssri/commit/fb1293e))
+
+
+
+<a name="4.1.4"></a>
+## [4.1.4](https://github.com/npm/ssri/compare/v4.1.3...v4.1.4) (2017-05-31)
+
+
+### Bug Fixes
+
+* **node:** older versions of node[@4](https://github.com/4) do not support base64buffer string parsing ([513df4e](https://github.com/npm/ssri/commit/513df4e))
+
+
+
+<a name="4.1.3"></a>
+## [4.1.3](https://github.com/npm/ssri/compare/v4.1.2...v4.1.3) (2017-05-24)
+
+
+### Bug Fixes
+
+* **check:** handle various bad hash corner cases better ([c2c262b](https://github.com/npm/ssri/commit/c2c262b))
+
+
+
+<a name="4.1.2"></a>
+## [4.1.2](https://github.com/npm/ssri/compare/v4.1.1...v4.1.2) (2017-04-18)
+
+
+### Bug Fixes
+
+* **stream:** _flush can be called multiple times. use on("end") ([b1c4805](https://github.com/npm/ssri/commit/b1c4805))
+
+
+
+<a name="4.1.1"></a>
+## [4.1.1](https://github.com/npm/ssri/compare/v4.1.0...v4.1.1) (2017-04-12)
+
+
+### Bug Fixes
+
+* **pickAlgorithm:** error if pickAlgorithm() is used in an empty Integrity ([fab470e](https://github.com/npm/ssri/commit/fab470e))
+
+
+
+<a name="4.1.0"></a>
+# [4.1.0](https://github.com/npm/ssri/compare/v4.0.0...v4.1.0) (2017-04-07)
+
+
+### Features
+
+* adding ssri.create for a crypto style interface (#2) ([96f52ad](https://github.com/npm/ssri/commit/96f52ad))
+
+
+
+<a name="4.0.0"></a>
+# [4.0.0](https://github.com/npm/ssri/compare/v3.0.2...v4.0.0) (2017-04-03)
+
+
+### Bug Fixes
+
+* **integrity:** should have changed the error code before. oops ([8381afa](https://github.com/npm/ssri/commit/8381afa))
+
+
+### BREAKING CHANGES
+
+* **integrity:** EBADCHECKSUM -> EINTEGRITY for verification errors
+
+
+
+<a name="3.0.2"></a>
+## [3.0.2](https://github.com/npm/ssri/compare/v3.0.1...v3.0.2) (2017-04-03)
+
+
+
+<a name="3.0.1"></a>
+## [3.0.1](https://github.com/npm/ssri/compare/v3.0.0...v3.0.1) (2017-04-03)
+
+
+### Bug Fixes
+
+* **package.json:** really should have these in the keywords because search ([a6ac6d0](https://github.com/npm/ssri/commit/a6ac6d0))
+
+
+
+<a name="3.0.0"></a>
+# [3.0.0](https://github.com/npm/ssri/compare/v2.0.0...v3.0.0) (2017-04-03)
+
+
+### Bug Fixes
+
+* **hashes:** IntegrityMetadata -> Hash ([d04aa1f](https://github.com/npm/ssri/commit/d04aa1f))
+
+
+### Features
+
+* **check:** return IntegrityMetadata on check success ([2301e74](https://github.com/npm/ssri/commit/2301e74))
+* **fromHex:** ssri.fromHex to make it easier to generate them from hex valus ([049b89e](https://github.com/npm/ssri/commit/049b89e))
+* **hex:** utility function for getting hex version of digest ([a9f021c](https://github.com/npm/ssri/commit/a9f021c))
+* **hexDigest:** added hexDigest method to Integrity objects too ([85208ba](https://github.com/npm/ssri/commit/85208ba))
+* **integrity:** add .isIntegrity and .isIntegrityMetadata ([1b29e6f](https://github.com/npm/ssri/commit/1b29e6f))
+* **integrityStream:** new stream that can both generate and check streamed data ([fd23e1b](https://github.com/npm/ssri/commit/fd23e1b))
+* **parse:** allow parsing straight into a single IntegrityMetadata object ([c8ddf48](https://github.com/npm/ssri/commit/c8ddf48))
+* **pickAlgorithm:** Intergrity#pickAlgorithm() added ([b97a796](https://github.com/npm/ssri/commit/b97a796))
+* **size:** calculate and update stream sizes ([02ed1ad](https://github.com/npm/ssri/commit/02ed1ad))
+
+
+### BREAKING CHANGES
+
+* **hashes:** `.isIntegrityMetadata` is now `.isHash`. Also, any references to `IntegrityMetadata` now refer to `Hash`.
+* **integrityStream:** createCheckerStream has been removed and replaced with a general-purpose integrityStream.
+
+To convert existing createCheckerStream code, move the `sri` argument into `opts.integrity` in integrityStream. All other options should be the same.
+* **check:** `checkData`, `checkStream`, and `createCheckerStream` now yield a whole IntegrityMetadata instance representing the first successful hash match.
+
+
+
+<a name="2.0.0"></a>
+# [2.0.0](https://github.com/npm/ssri/compare/v1.0.0...v2.0.0) (2017-03-24)
+
+
+### Bug Fixes
+
+* **strict-mode:** make regexes more rigid ([122a32c](https://github.com/npm/ssri/commit/122a32c))
+
+
+### Features
+
+* **api:** added serialize alias for unparse ([999b421](https://github.com/npm/ssri/commit/999b421))
+* **concat:** add Integrity#concat() ([cae12c7](https://github.com/npm/ssri/commit/cae12c7))
+* **pickAlgo:** pick the strongest algorithm provided, by default ([58c18f7](https://github.com/npm/ssri/commit/58c18f7))
+* **strict-mode:** strict SRI support ([3f0b64c](https://github.com/npm/ssri/commit/3f0b64c))
+* **stringify:** replaced unparse/serialize with stringify ([4acad30](https://github.com/npm/ssri/commit/4acad30))
+* **verification:** add opts.pickAlgorithm ([f72e658](https://github.com/npm/ssri/commit/f72e658))
+
+
+### BREAKING CHANGES
+
+* **pickAlgo:** ssri will prioritize specific hashes now
+* **stringify:** serialize and unparse have been removed. Use ssri.stringify instead.
+* **strict-mode:** functions that accepted an optional `sep` argument now expect `opts.sep`.
+
+
+
+<a name="1.0.0"></a>
+# 1.0.0 (2017-03-23)
+
+
+### Features
+
+* **api:** implemented initial api ([4fbb16b](https://github.com/npm/ssri/commit/4fbb16b))
+
+
+### BREAKING CHANGES
+
+* **api:** Initial API established.
diff --git a/server/node_modules/ssri/LICENSE.md b/server/node_modules/ssri/LICENSE.md
new file mode 100644
index 0000000..8d28acf
--- /dev/null
+++ b/server/node_modules/ssri/LICENSE.md
@@ -0,0 +1,16 @@
+ISC License
+
+Copyright (c) npm, Inc.
+
+Permission to use, copy, modify, and/or distribute this software for
+any purpose with or without fee is hereby granted, provided that the
+above copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE COPYRIGHT HOLDER DISCLAIMS
+ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
+USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/ssri/README.md b/server/node_modules/ssri/README.md
new file mode 100644
index 0000000..0cd41be
--- /dev/null
+++ b/server/node_modules/ssri/README.md
@@ -0,0 +1,528 @@
+# ssri [![npm version](https://img.shields.io/npm/v/ssri.svg)](https://npm.im/ssri) [![license](https://img.shields.io/npm/l/ssri.svg)](https://npm.im/ssri) [![Travis](https://img.shields.io/travis/npm/ssri.svg)](https://travis-ci.org/npm/ssri) [![AppVeyor](https://ci.appveyor.com/api/projects/status/github/npm/ssri?svg=true)](https://ci.appveyor.com/project/npm/ssri) [![Coverage Status](https://coveralls.io/repos/github/npm/ssri/badge.svg?branch=latest)](https://coveralls.io/github/npm/ssri?branch=latest)
+
+[`ssri`](https://github.com/npm/ssri), short for Standard Subresource
+Integrity, is a Node.js utility for parsing, manipulating, serializing,
+generating, and verifying [Subresource
+Integrity](https://w3c.github.io/webappsec/specs/subresourceintegrity/) hashes.
+
+## Install
+
+`$ npm install --save ssri`
+
+## Table of Contents
+
+* [Example](#example)
+* [Features](#features)
+* [Contributing](#contributing)
+* [API](#api)
+  * Parsing & Serializing
+    * [`parse`](#parse)
+    * [`stringify`](#stringify)
+    * [`Integrity#concat`](#integrity-concat)
+    * [`Integrity#merge`](#integrity-merge)
+    * [`Integrity#toString`](#integrity-to-string)
+    * [`Integrity#toJSON`](#integrity-to-json)
+    * [`Integrity#match`](#integrity-match)
+    * [`Integrity#pickAlgorithm`](#integrity-pick-algorithm)
+    * [`Integrity#hexDigest`](#integrity-hex-digest)
+  * Integrity Generation
+    * [`fromHex`](#from-hex)
+    * [`fromData`](#from-data)
+    * [`fromStream`](#from-stream)
+    * [`create`](#create)
+  * Integrity Verification
+    * [`checkData`](#check-data)
+    * [`checkStream`](#check-stream)
+    * [`integrityStream`](#integrity-stream)
+
+### Example
+
+```javascript
+const ssri = require('ssri')
+
+const integrity = 'sha512-9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo'
+
+// Parsing and serializing
+const parsed = ssri.parse(integrity)
+ssri.stringify(parsed) // === integrity (works on non-Integrity objects)
+parsed.toString() // === integrity
+
+// Async stream functions
+ssri.checkStream(fs.createReadStream('./my-file'), integrity).then(...)
+ssri.fromStream(fs.createReadStream('./my-file')).then(sri => {
+  sri.toString() === integrity
+})
+fs.createReadStream('./my-file').pipe(ssri.createCheckerStream(sri))
+
+// Sync data functions
+ssri.fromData(fs.readFileSync('./my-file')) // === parsed
+ssri.checkData(fs.readFileSync('./my-file'), integrity) // => 'sha512'
+```
+
+### Features
+
+* Parses and stringifies SRI strings.
+* Generates SRI strings from raw data or Streams.
+* Strict standard compliance.
+* `?foo` metadata option support.
+* Multiple entries for the same algorithm.
+* Object-based integrity hash manipulation.
+* Small footprint: no dependencies, concise implementation.
+* Full test coverage.
+* Customizable algorithm picker.
+
+### Contributing
+
+The ssri team enthusiastically welcomes contributions and project participation!
+There's a bunch of things you can do if you want to contribute! The [Contributor
+Guide](CONTRIBUTING.md) has all the information you need for everything from
+reporting bugs to contributing entire new features. Please don't hesitate to
+jump in if you'd like to, or even ask us questions if something isn't clear.
+
+### API
+
+#### <a name="parse"></a> `> ssri.parse(sri, [opts]) -> Integrity`
+
+Parses `sri` into an `Integrity` data structure. `sri` can be an integrity
+string, an `Hash`-like with `digest` and `algorithm` fields and an optional
+`options` field, or an `Integrity`-like object. The resulting object will be an
+`Integrity` instance that has this shape:
+
+```javascript
+{
+  'sha1': [{algorithm: 'sha1', digest: 'deadbeef', options: []}],
+  'sha512': [
+    {algorithm: 'sha512', digest: 'c0ffee', options: []},
+    {algorithm: 'sha512', digest: 'bad1dea', options: ['foo']}
+  ],
+}
+```
+
+If `opts.single` is truthy, a single `Hash` object will be returned. That is, a
+single object that looks like `{algorithm, digest, options}`, as opposed to a
+larger object with multiple of these.
+
+If `opts.strict` is truthy, the resulting object will be filtered such that
+it strictly follows the Subresource Integrity spec, throwing away any entries
+with any invalid components. This also means a restricted set of algorithms
+will be used -- the spec limits them to `sha256`, `sha384`, and `sha512`.
+
+Strict mode is recommended if the integrity strings are intended for use in
+browsers, or in other situations where strict adherence to the spec is needed.
+
+##### Example
+
+```javascript
+ssri.parse('sha512-9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo') // -> Integrity object
+```
+
+#### <a name="stringify"></a> `> ssri.stringify(sri, [opts]) -> String`
+
+This function is identical to [`Integrity#toString()`](#integrity-to-string),
+except it can be used on _any_ object that [`parse`](#parse) can handle -- that
+is, a string, an `Hash`-like, or an `Integrity`-like.
+
+The `opts.sep` option defines the string to use when joining multiple entries
+together. To be spec-compliant, this _must_ be whitespace. The default is a
+single space (`' '`).
+
+If `opts.strict` is true, the integrity string will be created using strict
+parsing rules. See [`ssri.parse`](#parse).
+
+##### Example
+
+```javascript
+// Useful for cleaning up input SRI strings:
+ssri.stringify('\n\rsha512-foo\n\t\tsha384-bar')
+// -> 'sha512-foo sha384-bar'
+
+// Hash-like: only a single entry.
+ssri.stringify({
+  algorithm: 'sha512',
+  digest:'9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==',
+  options: ['foo']
+})
+// ->
+// 'sha512-9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo'
+
+// Integrity-like: full multi-entry syntax. Similar to output of `ssri.parse`
+ssri.stringify({
+  'sha512': [
+    {
+      algorithm: 'sha512',
+      digest:'9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==',
+      options: ['foo']
+    }
+  ]
+})
+// ->
+// 'sha512-9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo'
+```
+
+#### <a name="integrity-concat"></a> `> Integrity#concat(otherIntegrity, [opts]) -> Integrity`
+
+Concatenates an `Integrity` object with another IntegrityLike, or an integrity
+string.
+
+This is functionally equivalent to concatenating the string format of both
+integrity arguments, and calling [`ssri.parse`](#ssri-parse) on the new string.
+
+If `opts.strict` is true, the new `Integrity` will be created using strict
+parsing rules. See [`ssri.parse`](#parse).
+
+##### Example
+
+```javascript
+// This will combine the integrity checks for two different versions of
+// your index.js file so you can use a single integrity string and serve
+// either of these to clients, from a single `<script>` tag.
+const desktopIntegrity = ssri.fromData(fs.readFileSync('./index.desktop.js'))
+const mobileIntegrity = ssri.fromData(fs.readFileSync('./index.mobile.js'))
+
+// Note that browsers (and ssri) will succeed as long as ONE of the entries
+// for the *prioritized* algorithm succeeds. That is, in order for this fallback
+// to work, both desktop and mobile *must* use the same `algorithm` values.
+desktopIntegrity.concat(mobileIntegrity)
+```
+
+#### <a name="integrity-merge"></a> `> Integrity#merge(otherIntegrity, [opts])`
+
+Safely merges another IntegrityLike or integrity string into an `Integrity`
+object.
+
+If the other integrity value has any algorithms in common with the current
+object, then the hash digests must match, or an error is thrown.
+
+Any new hashes will be added to the current object's set.
+
+This is useful when an integrity value may be upgraded with a stronger
+algorithm, you wish to prevent accidentally supressing integrity errors by
+overwriting the expected integrity value.
+
+##### Example
+
+```javascript
+const data = fs.readFileSync('data.txt')
+
+// integrity.txt contains 'sha1-X1UT+IIv2+UUWvM7ZNjZcNz5XG4='
+// because we were young, and didn't realize sha1 would not last
+const expectedIntegrity = ssri.parse(fs.readFileSync('integrity.txt', 'utf8'))
+const match = ssri.checkData(data, expectedIntegrity, {
+  algorithms: ['sha512', 'sha1']
+})
+if (!match) {
+  throw new Error('data corrupted or something!')
+}
+
+// get a stronger algo!
+if (match && match.algorithm !== 'sha512') {
+  const updatedIntegrity = ssri.fromData(data, { algorithms: ['sha512'] })
+  expectedIntegrity.merge(updatedIntegrity)
+  fs.writeFileSync('integrity.txt', expectedIntegrity.toString())
+  // file now contains
+  // 'sha1-X1UT+IIv2+UUWvM7ZNjZcNz5XG4= sha512-yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1+9vBnypkYWg=='
+}
+```
+
+#### <a name="integrity-to-string"></a> `> Integrity#toString([opts]) -> String`
+
+Returns the string representation of an `Integrity` object. All hash entries
+will be concatenated in the string by `opts.sep`, which defaults to `' '`.
+
+If you want to serialize an object that didn't come from an `ssri` function,
+use [`ssri.stringify()`](#stringify).
+
+If `opts.strict` is true, the integrity string will be created using strict
+parsing rules. See [`ssri.parse`](#parse).
+
+##### Example
+
+```javascript
+const integrity = 'sha512-9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo'
+
+ssri.parse(integrity).toString() === integrity
+```
+
+#### <a name="integrity-to-json"></a> `> Integrity#toJSON() -> String`
+
+Returns the string representation of an `Integrity` object. All hash entries
+will be concatenated in the string by `' '`.
+
+This is a convenience method so you can pass an `Integrity` object directly to `JSON.stringify`.
+For more info check out [toJSON() behavior on mdn](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#toJSON%28%29_behavior).
+
+##### Example
+
+```javascript
+const integrity = '"sha512-9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo"'
+
+JSON.stringify(ssri.parse(integrity)) === integrity
+```
+
+#### <a name="integrity-match"></a> `> Integrity#match(sri, [opts]) -> Hash | false`
+
+Returns the matching (truthy) hash if `Integrity` matches the argument passed as
+`sri`, which can be anything that [`parse`](#parse) will accept. `opts` will be
+passed through to `parse` and [`pickAlgorithm()`](#integrity-pick-algorithm).
+
+##### Example
+
+```javascript
+const integrity = 'sha512-9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A=='
+
+ssri.parse(integrity).match(integrity)
+// Hash {
+//   digest: '9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A=='
+//   algorithm: 'sha512'
+// }
+
+ssri.parse(integrity).match('sha1-deadbeef')
+// false
+```
+
+#### <a name="integrity-pick-algorithm"></a> `> Integrity#pickAlgorithm([opts]) -> String`
+
+Returns the "best" algorithm from those available in the integrity object.
+
+If `opts.pickAlgorithm` is provided, it will be passed two algorithms as
+arguments. ssri will prioritize whichever of the two algorithms is returned by
+this function. Note that the function may be called multiple times, and it
+**must** return one of the two algorithms provided. By default, ssri will make
+a best-effort to pick the strongest/most reliable of the given algorithms. It
+may intentionally deprioritize algorithms with known vulnerabilities.
+
+##### Example
+
+```javascript
+ssri.parse('sha1-WEakDigEST sha512-yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1').pickAlgorithm() // sha512
+```
+
+#### <a name="integrity-hex-digest"></a> `> Integrity#hexDigest() -> String`
+
+`Integrity` is assumed to be either a single-hash `Integrity` instance, or a
+`Hash` instance. Returns its `digest`, converted to a hex representation of the
+base64 data.
+
+##### Example
+
+```javascript
+ssri.parse('sha1-deadbeef').hexDigest() // '75e69d6de79f'
+```
+
+#### <a name="from-hex"></a> `> ssri.fromHex(hexDigest, algorithm, [opts]) -> Integrity`
+
+Creates an `Integrity` object with a single entry, based on a hex-formatted
+hash. This is a utility function to help convert existing shasums to the
+Integrity format, and is roughly equivalent to something like:
+
+```javascript
+algorithm + '-' + Buffer.from(hexDigest, 'hex').toString('base64')
+```
+
+`opts.options` may optionally be passed in: it must be an array of option
+strings that will be added to all generated integrity hashes generated by
+`fromData`. This is a loosely-specified feature of SRIs, and currently has no
+specified semantics besides being `?`-separated. Use at your own risk, and
+probably avoid if your integrity strings are meant to be used with browsers.
+
+If `opts.strict` is true, the integrity object will be created using strict
+parsing rules. See [`ssri.parse`](#parse).
+
+If `opts.single` is true, a single `Hash` object will be returned.
+
+##### Example
+
+```javascript
+ssri.fromHex('75e69d6de79f', 'sha1').toString() // 'sha1-deadbeef'
+```
+
+#### <a name="from-data"></a> `> ssri.fromData(data, [opts]) -> Integrity`
+
+Creates an `Integrity` object from either string or `Buffer` data, calculating
+all the requested hashes and adding any specified options to the object.
+
+`opts.algorithms` determines which algorithms to generate hashes for. All
+results will be included in a single `Integrity` object. The default value for
+`opts.algorithms` is `['sha512']`. All algorithm strings must be hashes listed
+in `crypto.getHashes()` for the host Node.js platform.
+
+`opts.options` may optionally be passed in: it must be an array of option
+strings that will be added to all generated integrity hashes generated by
+`fromData`. This is a loosely-specified feature of SRIs, and currently has no
+specified semantics besides being `?`-separated. Use at your own risk, and
+probably avoid if your integrity strings are meant to be used with browsers.
+
+If `opts.strict` is true, the integrity object will be created using strict
+parsing rules. See [`ssri.parse`](#parse).
+
+##### Example
+
+```javascript
+const integrityObj = ssri.fromData('foobarbaz', {
+  algorithms: ['sha256', 'sha384', 'sha512']
+})
+integrity.toString('\n')
+// ->
+// sha256-l981iLWj8kurw4UbNy8Lpxqdzd7UOxS50Glhv8FwfZ0=
+// sha384-irnCxQ0CfQhYGlVAUdwTPC9bF3+YWLxlaDGM4xbYminxpbXEq+D+2GCEBTxcjES9
+// sha512-yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1+9vBnypkYWg==
+```
+
+#### <a name="from-stream"></a> `> ssri.fromStream(stream, [opts]) -> Promise<Integrity>`
+
+Returns a Promise of an Integrity object calculated by reading data from
+a given `stream`.
+
+It accepts both `opts.algorithms` and `opts.options`, which are documented as
+part of [`ssri.fromData`](#from-data).
+
+Additionally, `opts.Promise` may be passed in to inject a Promise library of
+choice. By default, ssri will use Node's built-in Promises.
+
+If `opts.strict` is true, the integrity object will be created using strict
+parsing rules. See [`ssri.parse`](#parse).
+
+##### Example
+
+```javascript
+ssri.fromStream(fs.createReadStream('index.js'), {
+  algorithms: ['sha1', 'sha512']
+}).then(integrity => {
+  return ssri.checkStream(fs.createReadStream('index.js'), integrity)
+}) // succeeds
+```
+
+#### <a name="create"></a> `> ssri.create([opts]) -> <Hash>`
+
+Returns a Hash object with `update(<Buffer or string>[,enc])` and `digest()` methods.
+
+
+The Hash object provides the same methods as [crypto class Hash](https://nodejs.org/dist/latest-v6.x/docs/api/crypto.html#crypto_class_hash).
+`digest()` accepts no arguments and returns an Integrity object calculated by reading data from
+calls to update.
+
+It accepts both `opts.algorithms` and `opts.options`, which are documented as
+part of [`ssri.fromData`](#from-data).
+
+If `opts.strict` is true, the integrity object will be created using strict
+parsing rules. See [`ssri.parse`](#parse).
+
+##### Example
+
+```javascript
+const integrity = ssri.create().update('foobarbaz').digest()
+integrity.toString()
+// ->
+// sha512-yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1+9vBnypkYWg==
+```
+
+#### <a name="check-data"></a> `> ssri.checkData(data, sri, [opts]) -> Hash|false`
+
+Verifies `data` integrity against an `sri` argument. `data` may be either a
+`String` or a `Buffer`, and `sri` can be any subresource integrity
+representation that [`ssri.parse`](#parse) can handle.
+
+If verification succeeds, `checkData` will return the name of the algorithm that
+was used for verification (a truthy value). Otherwise, it will return `false`.
+
+If `opts.pickAlgorithm` is provided, it will be used by
+[`Integrity#pickAlgorithm`](#integrity-pick-algorithm) when deciding which of
+the available digests to match against.
+
+If `opts.error` is true, and verification fails, `checkData` will throw either
+an `EBADSIZE` or an `EINTEGRITY` error, instead of just returning false.
+
+##### Example
+
+```javascript
+const data = fs.readFileSync('index.js')
+ssri.checkData(data, ssri.fromData(data)) // -> 'sha512'
+ssri.checkData(data, 'sha256-l981iLWj8kurw4UbNy8Lpxqdzd7UOxS50Glhv8FwfZ0')
+ssri.checkData(data, 'sha1-BaDDigEST') // -> false
+ssri.checkData(data, 'sha1-BaDDigEST', {error: true}) // -> Error! EINTEGRITY
+```
+
+#### <a name="check-stream"></a> `> ssri.checkStream(stream, sri, [opts]) -> Promise<Hash>`
+
+Verifies the contents of `stream` against an `sri` argument. `stream` will be
+consumed in its entirety by this process. `sri` can be any subresource integrity
+representation that [`ssri.parse`](#parse) can handle.
+
+`checkStream` will return a Promise that either resolves to the
+`Hash` that succeeded verification, or, if the verification fails
+or an error happens with `stream`, the Promise will be rejected.
+
+If the Promise is rejected because verification failed, the returned error will
+have `err.code` as `EINTEGRITY`.
+
+If `opts.size` is given, it will be matched against the stream size. An error
+with `err.code` `EBADSIZE` will be returned by a rejection if the expected size
+and actual size fail to match.
+
+If `opts.pickAlgorithm` is provided, it will be used by
+[`Integrity#pickAlgorithm`](#integrity-pick-algorithm) when deciding which of
+the available digests to match against.
+
+##### Example
+
+```javascript
+const integrity = ssri.fromData(fs.readFileSync('index.js'))
+
+ssri.checkStream(
+  fs.createReadStream('index.js'),
+  integrity
+)
+// ->
+// Promise<{
+//   algorithm: 'sha512',
+//   digest: 'sha512-yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1'
+// }>
+
+ssri.checkStream(
+  fs.createReadStream('index.js'),
+  'sha256-l981iLWj8kurw4UbNy8Lpxqdzd7UOxS50Glhv8FwfZ0'
+) // -> Promise<Hash>
+
+ssri.checkStream(
+  fs.createReadStream('index.js'),
+  'sha1-BaDDigEST'
+) // -> Promise<Error<{code: 'EINTEGRITY'}>>
+```
+
+#### <a name="integrity-stream"></a> `> integrityStream([opts]) -> IntegrityStream`
+
+Returns a `Transform` stream that data can be piped through in order to generate
+and optionally check data integrity for piped data. When the stream completes
+successfully, it emits `size` and `integrity` events, containing the total
+number of bytes processed and a calculated `Integrity` instance based on stream
+data, respectively.
+
+If `opts.algorithms` is passed in, the listed algorithms will be calculated when
+generating the final `Integrity` instance. The default is `['sha512']`.
+
+If `opts.single` is passed in, a single `Hash` instance will be returned.
+
+If `opts.integrity` is passed in, it should be an `integrity` value understood
+by [`parse`](#parse) that the stream will check the data against. If
+verification succeeds, the integrity stream will emit a `verified` event whose
+value is a single `Hash` object that is the one that succeeded verification. If
+verification fails, the stream will error with an `EINTEGRITY` error code.
+
+If `opts.size` is given, it will be matched against the stream size. An error
+with `err.code` `EBADSIZE` will be emitted by the stream if the expected size
+and actual size fail to match.
+
+If `opts.pickAlgorithm` is provided, it will be passed two algorithms as
+arguments. ssri will prioritize whichever of the two algorithms is returned by
+this function. Note that the function may be called multiple times, and it
+**must** return one of the two algorithms provided. By default, ssri will make
+a best-effort to pick the strongest/most reliable of the given algorithms. It
+may intentionally deprioritize algorithms with known vulnerabilities.
+
+##### Example
+
+```javascript
+const integrity = ssri.fromData(fs.readFileSync('index.js'))
+fs.createReadStream('index.js')
+.pipe(ssri.integrityStream({integrity}))
+```
diff --git a/server/node_modules/ssri/index.js b/server/node_modules/ssri/index.js
new file mode 100644
index 0000000..2b30984
--- /dev/null
+++ b/server/node_modules/ssri/index.js
@@ -0,0 +1,470 @@
+'use strict'
+
+const crypto = require('crypto')
+const MiniPass = require('minipass')
+
+const SPEC_ALGORITHMS = ['sha256', 'sha384', 'sha512']
+
+// TODO: this should really be a hardcoded list of algorithms we support,
+// rather than [a-z0-9].
+const BASE64_REGEX = /^[a-z0-9+/]+(?:=?=?)$/i
+const SRI_REGEX = /^([a-z0-9]+)-([^?]+)([?\S*]*)$/
+const STRICT_SRI_REGEX = /^([a-z0-9]+)-([A-Za-z0-9+/=]{44,88})(\?[\x21-\x7E]*)?$/
+const VCHAR_REGEX = /^[\x21-\x7E]+$/
+
+const defaultOpts = {
+  algorithms: ['sha512'],
+  error: false,
+  options: [],
+  pickAlgorithm: getPrioritizedHash,
+  sep: ' ',
+  single: false,
+  strict: false
+}
+
+const ssriOpts = (opts = {}) => ({ ...defaultOpts, ...opts })
+
+const getOptString = options => !options || !options.length
+  ? ''
+  : `?${options.join('?')}`
+
+const _onEnd = Symbol('_onEnd')
+const _getOptions = Symbol('_getOptions')
+class IntegrityStream extends MiniPass {
+  constructor (opts) {
+    super()
+    this.size = 0
+    this.opts = opts
+
+    // may be overridden later, but set now for class consistency
+    this[_getOptions]()
+
+    // options used for calculating stream.  can't be changed.
+    const { algorithms = defaultOpts.algorithms } = opts
+    this.algorithms = Array.from(
+      new Set(algorithms.concat(this.algorithm ? [this.algorithm] : []))
+    )
+    this.hashes = this.algorithms.map(crypto.createHash)
+  }
+
+  [_getOptions] () {
+    const {
+      integrity,
+      size,
+      options
+    } = { ...defaultOpts, ...this.opts }
+
+    // For verification
+    this.sri = integrity ? parse(integrity, this.opts) : null
+    this.expectedSize = size
+    this.goodSri = this.sri ? !!Object.keys(this.sri).length : false
+    this.algorithm = this.goodSri ? this.sri.pickAlgorithm(this.opts) : null
+    this.digests = this.goodSri ? this.sri[this.algorithm] : null
+    this.optString = getOptString(options)
+  }
+
+  emit (ev, data) {
+    if (ev === 'end') this[_onEnd]()
+    return super.emit(ev, data)
+  }
+
+  write (data) {
+    this.size += data.length
+    this.hashes.forEach(h => h.update(data))
+    return super.write(data)
+  }
+
+  [_onEnd] () {
+    if (!this.goodSri) {
+      this[_getOptions]()
+    }
+    const newSri = parse(this.hashes.map((h, i) => {
+      return `${this.algorithms[i]}-${h.digest('base64')}${this.optString}`
+    }).join(' '), this.opts)
+    // Integrity verification mode
+    const match = this.goodSri && newSri.match(this.sri, this.opts)
+    if (typeof this.expectedSize === 'number' && this.size !== this.expectedSize) {
+      const err = new Error(`stream size mismatch when checking ${this.sri}.\n  Wanted: ${this.expectedSize}\n  Found: ${this.size}`)
+      err.code = 'EBADSIZE'
+      err.found = this.size
+      err.expected = this.expectedSize
+      err.sri = this.sri
+      this.emit('error', err)
+    } else if (this.sri && !match) {
+      const err = new Error(`${this.sri} integrity checksum failed when using ${this.algorithm}: wanted ${this.digests} but got ${newSri}. (${this.size} bytes)`)
+      err.code = 'EINTEGRITY'
+      err.found = newSri
+      err.expected = this.digests
+      err.algorithm = this.algorithm
+      err.sri = this.sri
+      this.emit('error', err)
+    } else {
+      this.emit('size', this.size)
+      this.emit('integrity', newSri)
+      match && this.emit('verified', match)
+    }
+  }
+}
+
+class Hash {
+  get isHash () { return true }
+  constructor (hash, opts) {
+    opts = ssriOpts(opts)
+    const strict = !!opts.strict
+    this.source = hash.trim()
+
+    // set default values so that we make V8 happy to
+    // always see a familiar object template.
+    this.digest = ''
+    this.algorithm = ''
+    this.options = []
+
+    // 3.1. Integrity metadata (called "Hash" by ssri)
+    // https://w3c.github.io/webappsec-subresource-integrity/#integrity-metadata-description
+    const match = this.source.match(
+      strict
+        ? STRICT_SRI_REGEX
+        : SRI_REGEX
+    )
+    if (!match) { return }
+    if (strict && !SPEC_ALGORITHMS.some(a => a === match[1])) { return }
+    this.algorithm = match[1]
+    this.digest = match[2]
+
+    const rawOpts = match[3]
+    if (rawOpts) {
+      this.options = rawOpts.slice(1).split('?')
+    }
+  }
+
+  hexDigest () {
+    return this.digest && Buffer.from(this.digest, 'base64').toString('hex')
+  }
+
+  toJSON () {
+    return this.toString()
+  }
+
+  toString (opts) {
+    opts = ssriOpts(opts)
+    if (opts.strict) {
+      // Strict mode enforces the standard as close to the foot of the
+      // letter as it can.
+      if (!(
+        // The spec has very restricted productions for algorithms.
+        // https://www.w3.org/TR/CSP2/#source-list-syntax
+        SPEC_ALGORITHMS.some(x => x === this.algorithm) &&
+        // Usually, if someone insists on using a "different" base64, we
+        // leave it as-is, since there's multiple standards, and the
+        // specified is not a URL-safe variant.
+        // https://www.w3.org/TR/CSP2/#base64_value
+        this.digest.match(BASE64_REGEX) &&
+        // Option syntax is strictly visual chars.
+        // https://w3c.github.io/webappsec-subresource-integrity/#grammardef-option-expression
+        // https://tools.ietf.org/html/rfc5234#appendix-B.1
+        this.options.every(opt => opt.match(VCHAR_REGEX))
+      )) {
+        return ''
+      }
+    }
+    const options = this.options && this.options.length
+      ? `?${this.options.join('?')}`
+      : ''
+    return `${this.algorithm}-${this.digest}${options}`
+  }
+}
+
+class Integrity {
+  get isIntegrity () { return true }
+  toJSON () {
+    return this.toString()
+  }
+
+  isEmpty () {
+    return Object.keys(this).length === 0
+  }
+
+  toString (opts) {
+    opts = ssriOpts(opts)
+    let sep = opts.sep || ' '
+    if (opts.strict) {
+      // Entries must be separated by whitespace, according to spec.
+      sep = sep.replace(/\S+/g, ' ')
+    }
+    return Object.keys(this).map(k => {
+      return this[k].map(hash => {
+        return Hash.prototype.toString.call(hash, opts)
+      }).filter(x => x.length).join(sep)
+    }).filter(x => x.length).join(sep)
+  }
+
+  concat (integrity, opts) {
+    opts = ssriOpts(opts)
+    const other = typeof integrity === 'string'
+      ? integrity
+      : stringify(integrity, opts)
+    return parse(`${this.toString(opts)} ${other}`, opts)
+  }
+
+  hexDigest () {
+    return parse(this, { single: true }).hexDigest()
+  }
+
+  // add additional hashes to an integrity value, but prevent
+  // *changing* an existing integrity hash.
+  merge (integrity, opts) {
+    opts = ssriOpts(opts)
+    const other = parse(integrity, opts)
+    for (const algo in other) {
+      if (this[algo]) {
+        if (!this[algo].find(hash =>
+          other[algo].find(otherhash =>
+            hash.digest === otherhash.digest))) {
+          throw new Error('hashes do not match, cannot update integrity')
+        }
+      } else {
+        this[algo] = other[algo]
+      }
+    }
+  }
+
+  match (integrity, opts) {
+    opts = ssriOpts(opts)
+    const other = parse(integrity, opts)
+    const algo = other.pickAlgorithm(opts)
+    return (
+      this[algo] &&
+      other[algo] &&
+      this[algo].find(hash =>
+        other[algo].find(otherhash =>
+          hash.digest === otherhash.digest
+        )
+      )
+    ) || false
+  }
+
+  pickAlgorithm (opts) {
+    opts = ssriOpts(opts)
+    const pickAlgorithm = opts.pickAlgorithm
+    const keys = Object.keys(this)
+    return keys.reduce((acc, algo) => {
+      return pickAlgorithm(acc, algo) || acc
+    })
+  }
+}
+
+module.exports.parse = parse
+function parse (sri, opts) {
+  if (!sri) return null
+  opts = ssriOpts(opts)
+  if (typeof sri === 'string') {
+    return _parse(sri, opts)
+  } else if (sri.algorithm && sri.digest) {
+    const fullSri = new Integrity()
+    fullSri[sri.algorithm] = [sri]
+    return _parse(stringify(fullSri, opts), opts)
+  } else {
+    return _parse(stringify(sri, opts), opts)
+  }
+}
+
+function _parse (integrity, opts) {
+  // 3.4.3. Parse metadata
+  // https://w3c.github.io/webappsec-subresource-integrity/#parse-metadata
+  if (opts.single) {
+    return new Hash(integrity, opts)
+  }
+  const hashes = integrity.trim().split(/\s+/).reduce((acc, string) => {
+    const hash = new Hash(string, opts)
+    if (hash.algorithm && hash.digest) {
+      const algo = hash.algorithm
+      if (!acc[algo]) { acc[algo] = [] }
+      acc[algo].push(hash)
+    }
+    return acc
+  }, new Integrity())
+  return hashes.isEmpty() ? null : hashes
+}
+
+module.exports.stringify = stringify
+function stringify (obj, opts) {
+  opts = ssriOpts(opts)
+  if (obj.algorithm && obj.digest) {
+    return Hash.prototype.toString.call(obj, opts)
+  } else if (typeof obj === 'string') {
+    return stringify(parse(obj, opts), opts)
+  } else {
+    return Integrity.prototype.toString.call(obj, opts)
+  }
+}
+
+module.exports.fromHex = fromHex
+function fromHex (hexDigest, algorithm, opts) {
+  opts = ssriOpts(opts)
+  const optString = getOptString(opts.options)
+  return parse(
+    `${algorithm}-${
+      Buffer.from(hexDigest, 'hex').toString('base64')
+    }${optString}`, opts
+  )
+}
+
+module.exports.fromData = fromData
+function fromData (data, opts) {
+  opts = ssriOpts(opts)
+  const algorithms = opts.algorithms
+  const optString = getOptString(opts.options)
+  return algorithms.reduce((acc, algo) => {
+    const digest = crypto.createHash(algo).update(data).digest('base64')
+    const hash = new Hash(
+      `${algo}-${digest}${optString}`,
+      opts
+    )
+    /* istanbul ignore else - it would be VERY strange if the string we
+     * just calculated with an algo did not have an algo or digest.
+     */
+    if (hash.algorithm && hash.digest) {
+      const algo = hash.algorithm
+      if (!acc[algo]) { acc[algo] = [] }
+      acc[algo].push(hash)
+    }
+    return acc
+  }, new Integrity())
+}
+
+module.exports.fromStream = fromStream
+function fromStream (stream, opts) {
+  opts = ssriOpts(opts)
+  const istream = integrityStream(opts)
+  return new Promise((resolve, reject) => {
+    stream.pipe(istream)
+    stream.on('error', reject)
+    istream.on('error', reject)
+    let sri
+    istream.on('integrity', s => { sri = s })
+    istream.on('end', () => resolve(sri))
+    istream.on('data', () => {})
+  })
+}
+
+module.exports.checkData = checkData
+function checkData (data, sri, opts) {
+  opts = ssriOpts(opts)
+  sri = parse(sri, opts)
+  if (!sri || !Object.keys(sri).length) {
+    if (opts.error) {
+      throw Object.assign(
+        new Error('No valid integrity hashes to check against'), {
+          code: 'EINTEGRITY'
+        }
+      )
+    } else {
+      return false
+    }
+  }
+  const algorithm = sri.pickAlgorithm(opts)
+  const digest = crypto.createHash(algorithm).update(data).digest('base64')
+  const newSri = parse({ algorithm, digest })
+  const match = newSri.match(sri, opts)
+  if (match || !opts.error) {
+    return match
+  } else if (typeof opts.size === 'number' && (data.length !== opts.size)) {
+    const err = new Error(`data size mismatch when checking ${sri}.\n  Wanted: ${opts.size}\n  Found: ${data.length}`)
+    err.code = 'EBADSIZE'
+    err.found = data.length
+    err.expected = opts.size
+    err.sri = sri
+    throw err
+  } else {
+    const err = new Error(`Integrity checksum failed when using ${algorithm}: Wanted ${sri}, but got ${newSri}. (${data.length} bytes)`)
+    err.code = 'EINTEGRITY'
+    err.found = newSri
+    err.expected = sri
+    err.algorithm = algorithm
+    err.sri = sri
+    throw err
+  }
+}
+
+module.exports.checkStream = checkStream
+function checkStream (stream, sri, opts) {
+  opts = ssriOpts(opts)
+  opts.integrity = sri
+  sri = parse(sri, opts)
+  if (!sri || !Object.keys(sri).length) {
+    return Promise.reject(Object.assign(
+      new Error('No valid integrity hashes to check against'), {
+        code: 'EINTEGRITY'
+      }
+    ))
+  }
+  const checker = integrityStream(opts)
+  return new Promise((resolve, reject) => {
+    stream.pipe(checker)
+    stream.on('error', reject)
+    checker.on('error', reject)
+    let sri
+    checker.on('verified', s => { sri = s })
+    checker.on('end', () => resolve(sri))
+    checker.on('data', () => {})
+  })
+}
+
+module.exports.integrityStream = integrityStream
+function integrityStream (opts = {}) {
+  return new IntegrityStream(opts)
+}
+
+module.exports.create = createIntegrity
+function createIntegrity (opts) {
+  opts = ssriOpts(opts)
+  const algorithms = opts.algorithms
+  const optString = getOptString(opts.options)
+
+  const hashes = algorithms.map(crypto.createHash)
+
+  return {
+    update: function (chunk, enc) {
+      hashes.forEach(h => h.update(chunk, enc))
+      return this
+    },
+    digest: function (enc) {
+      const integrity = algorithms.reduce((acc, algo) => {
+        const digest = hashes.shift().digest('base64')
+        const hash = new Hash(
+          `${algo}-${digest}${optString}`,
+          opts
+        )
+        /* istanbul ignore else - it would be VERY strange if the hash we
+         * just calculated with an algo did not have an algo or digest.
+         */
+        if (hash.algorithm && hash.digest) {
+          const algo = hash.algorithm
+          if (!acc[algo]) { acc[algo] = [] }
+          acc[algo].push(hash)
+        }
+        return acc
+      }, new Integrity())
+
+      return integrity
+    }
+  }
+}
+
+const NODE_HASHES = new Set(crypto.getHashes())
+
+// This is a Best Effort™ at a reasonable priority for hash algos
+const DEFAULT_PRIORITY = [
+  'md5', 'whirlpool', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512',
+  // TODO - it's unclear _which_ of these Node will actually use as its name
+  //        for the algorithm, so we guesswork it based on the OpenSSL names.
+  'sha3',
+  'sha3-256', 'sha3-384', 'sha3-512',
+  'sha3_256', 'sha3_384', 'sha3_512'
+].filter(algo => NODE_HASHES.has(algo))
+
+function getPrioritizedHash (algo1, algo2) {
+  return DEFAULT_PRIORITY.indexOf(algo1.toLowerCase()) >= DEFAULT_PRIORITY.indexOf(algo2.toLowerCase())
+    ? algo1
+    : algo2
+}
diff --git a/server/node_modules/ssri/package.json b/server/node_modules/ssri/package.json
new file mode 100644
index 0000000..4af1a3c
--- /dev/null
+++ b/server/node_modules/ssri/package.json
@@ -0,0 +1,52 @@
+{
+  "name": "ssri",
+  "version": "8.0.1",
+  "description": "Standard Subresource Integrity library -- parses, serializes, generates, and verifies integrity metadata according to the SRI spec.",
+  "main": "index.js",
+  "files": [],
+  "scripts": {
+    "prerelease": "npm t",
+    "postrelease": "npm publish",
+    "prepublishOnly": "git push --follow-tags",
+    "posttest": "npm run lint",
+    "release": "standard-version -s",
+    "test": "tap",
+    "coverage": "tap",
+    "lint": "standard"
+  },
+  "tap": {
+    "check-coverage": true
+  },
+  "repository": "https://github.com/npm/ssri",
+  "keywords": [
+    "w3c",
+    "web",
+    "security",
+    "integrity",
+    "checksum",
+    "hashing",
+    "subresource integrity",
+    "sri",
+    "sri hash",
+    "sri string",
+    "sri generator",
+    "html"
+  ],
+  "author": {
+    "name": "Kat Marchán",
+    "email": "kzm@sykosomatic.org",
+    "twitter": "maybekatz"
+  },
+  "license": "ISC",
+  "dependencies": {
+    "minipass": "^3.1.1"
+  },
+  "devDependencies": {
+    "standard": "^16.0.3",
+    "standard-version": "^9.1.0",
+    "tap": "^14.10.6"
+  },
+  "engines": {
+    "node": ">= 8"
+  }
+}
diff --git a/server/node_modules/statuses/HISTORY.md b/server/node_modules/statuses/HISTORY.md
new file mode 100644
index 0000000..dc549b8
--- /dev/null
+++ b/server/node_modules/statuses/HISTORY.md
@@ -0,0 +1,87 @@
+2.0.2 / 2025-06-06
+==================
+
+  * Migrate to `String.prototype.slice()`
+
+2.0.1 / 2021-01-03
+==================
+
+  * Fix returning values from `Object.prototype`
+
+2.0.0 / 2020-04-19
+==================
+
+  * Drop support for Node.js 0.6
+  * Fix messaging casing of `418 I'm a Teapot`
+  * Remove code 306
+  * Remove `status[code]` exports; use `status.message[code]`
+  * Remove `status[msg]` exports; use `status.code[msg]`
+  * Rename `425 Unordered Collection` to standard `425 Too Early`
+  * Rename `STATUS_CODES` export to `message`
+  * Return status message for `statuses(code)` when given code
+
+1.5.0 / 2018-03-27
+==================
+
+  * Add `103 Early Hints`
+
+1.4.0 / 2017-10-20
+==================
+
+  * Add `STATUS_CODES` export
+
+1.3.1 / 2016-11-11
+==================
+
+  * Fix return type in JSDoc
+
+1.3.0 / 2016-05-17
+==================
+
+  * Add `421 Misdirected Request`
+  * perf: enable strict mode
+
+1.2.1 / 2015-02-01
+==================
+
+  * Fix message for status 451
+    - `451 Unavailable For Legal Reasons`
+
+1.2.0 / 2014-09-28
+==================
+
+  * Add `208 Already Repored`
+  * Add `226 IM Used`
+  * Add `306 (Unused)`
+  * Add `415 Unable For Legal Reasons`
+  * Add `508 Loop Detected`
+
+1.1.1 / 2014-09-24
+==================
+
+  * Add missing 308 to `codes.json`
+
+1.1.0 / 2014-09-21
+==================
+
+  * Add `codes.json` for universal support
+
+1.0.4 / 2014-08-20
+==================
+
+  * Package cleanup
+
+1.0.3 / 2014-06-08
+==================
+
+  * Add 308 to `.redirect` category
+
+1.0.2 / 2014-03-13
+==================
+
+  * Add `.retry` category
+
+1.0.1 / 2014-03-12
+==================
+
+  * Initial release
diff --git a/server/node_modules/statuses/LICENSE b/server/node_modules/statuses/LICENSE
new file mode 100644
index 0000000..28a3161
--- /dev/null
+++ b/server/node_modules/statuses/LICENSE
@@ -0,0 +1,23 @@
+
+The MIT License (MIT)
+
+Copyright (c) 2014 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2016 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/statuses/README.md b/server/node_modules/statuses/README.md
new file mode 100644
index 0000000..89d542f
--- /dev/null
+++ b/server/node_modules/statuses/README.md
@@ -0,0 +1,139 @@
+# statuses
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][ci-image]][ci-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+[![OpenSSF Scorecard Badge][ossf-scorecard-badge]][ossf-scorecard-visualizer]
+
+HTTP status utility for node.
+
+This module provides a list of status codes and messages sourced from
+a few different projects:
+
+  * The [IANA Status Code Registry](https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml)
+  * The [Node.js project](https://nodejs.org/)
+  * The [NGINX project](https://www.nginx.com/)
+  * The [Apache HTTP Server project](https://httpd.apache.org/)
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install statuses
+```
+
+## API
+
+
+
+```js
+var status = require('statuses')
+```
+
+### status(code)
+
+Returns the status message string for a known HTTP status code. The code
+may be a number or a string. An error is thrown for an unknown status code.
+
+
+
+```js
+status(403) // => 'Forbidden'
+status('403') // => 'Forbidden'
+status(306) // throws
+```
+
+### status(msg)
+
+Returns the numeric status code for a known HTTP status message. The message
+is case-insensitive. An error is thrown for an unknown status message.
+
+
+
+```js
+status('forbidden') // => 403
+status('Forbidden') // => 403
+status('foo') // throws
+```
+
+### status.codes
+
+Returns an array of all the status codes as `Integer`s.
+
+### status.code[msg]
+
+Returns the numeric status code for a known status message (in lower-case),
+otherwise `undefined`.
+
+
+
+```js
+status['not found'] // => 404
+```
+
+### status.empty[code]
+
+Returns `true` if a status code expects an empty body.
+
+
+
+```js
+status.empty[200] // => undefined
+status.empty[204] // => true
+status.empty[304] // => true
+```
+
+### status.message[code]
+
+Returns the string message for a known numeric status code, otherwise
+`undefined`. This object is the same format as the
+[Node.js http module `http.STATUS_CODES`](https://nodejs.org/dist/latest/docs/api/http.html#http_http_status_codes).
+
+
+
+```js
+status.message[404] // => 'Not Found'
+```
+
+### status.redirect[code]
+
+Returns `true` if a status code is a valid redirect status.
+
+
+
+```js
+status.redirect[200] // => undefined
+status.redirect[301] // => true
+```
+
+### status.retry[code]
+
+Returns `true` if you should retry the rest.
+
+
+
+```js
+status.retry[501] // => undefined
+status.retry[503] // => true
+```
+
+## License
+
+[MIT](LICENSE)
+
+[ci-image]: https://badgen.net/github/checks/jshttp/statuses/master?label=ci
+[ci-url]: https://github.com/jshttp/statuses/actions?query=workflow%3Aci
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/statuses/master
+[coveralls-url]: https://coveralls.io/r/jshttp/statuses?branch=master
+[node-version-image]: https://badgen.net/npm/node/statuses
+[node-version-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/statuses
+[npm-url]: https://npmjs.org/package/statuses
+[npm-version-image]: https://badgen.net/npm/v/statuses
+[ossf-scorecard-badge]: https://api.securityscorecards.dev/projects/github.com/jshttp/statuses/badge
+[ossf-scorecard-visualizer]: https://kooltheba.github.io/openssf-scorecard-api-visualizer/#/projects/github.com/jshttp/statuses
diff --git a/server/node_modules/statuses/codes.json b/server/node_modules/statuses/codes.json
new file mode 100644
index 0000000..1333ed1
--- /dev/null
+++ b/server/node_modules/statuses/codes.json
@@ -0,0 +1,65 @@
+{
+  "100": "Continue",
+  "101": "Switching Protocols",
+  "102": "Processing",
+  "103": "Early Hints",
+  "200": "OK",
+  "201": "Created",
+  "202": "Accepted",
+  "203": "Non-Authoritative Information",
+  "204": "No Content",
+  "205": "Reset Content",
+  "206": "Partial Content",
+  "207": "Multi-Status",
+  "208": "Already Reported",
+  "226": "IM Used",
+  "300": "Multiple Choices",
+  "301": "Moved Permanently",
+  "302": "Found",
+  "303": "See Other",
+  "304": "Not Modified",
+  "305": "Use Proxy",
+  "307": "Temporary Redirect",
+  "308": "Permanent Redirect",
+  "400": "Bad Request",
+  "401": "Unauthorized",
+  "402": "Payment Required",
+  "403": "Forbidden",
+  "404": "Not Found",
+  "405": "Method Not Allowed",
+  "406": "Not Acceptable",
+  "407": "Proxy Authentication Required",
+  "408": "Request Timeout",
+  "409": "Conflict",
+  "410": "Gone",
+  "411": "Length Required",
+  "412": "Precondition Failed",
+  "413": "Payload Too Large",
+  "414": "URI Too Long",
+  "415": "Unsupported Media Type",
+  "416": "Range Not Satisfiable",
+  "417": "Expectation Failed",
+  "418": "I'm a Teapot",
+  "421": "Misdirected Request",
+  "422": "Unprocessable Entity",
+  "423": "Locked",
+  "424": "Failed Dependency",
+  "425": "Too Early",
+  "426": "Upgrade Required",
+  "428": "Precondition Required",
+  "429": "Too Many Requests",
+  "431": "Request Header Fields Too Large",
+  "451": "Unavailable For Legal Reasons",
+  "500": "Internal Server Error",
+  "501": "Not Implemented",
+  "502": "Bad Gateway",
+  "503": "Service Unavailable",
+  "504": "Gateway Timeout",
+  "505": "HTTP Version Not Supported",
+  "506": "Variant Also Negotiates",
+  "507": "Insufficient Storage",
+  "508": "Loop Detected",
+  "509": "Bandwidth Limit Exceeded",
+  "510": "Not Extended",
+  "511": "Network Authentication Required"
+}
diff --git a/server/node_modules/statuses/index.js b/server/node_modules/statuses/index.js
new file mode 100644
index 0000000..ea351c5
--- /dev/null
+++ b/server/node_modules/statuses/index.js
@@ -0,0 +1,146 @@
+/*!
+ * statuses
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var codes = require('./codes.json')
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = status
+
+// status code to message map
+status.message = codes
+
+// status message (lower-case) to code map
+status.code = createMessageToStatusCodeMap(codes)
+
+// array of status codes
+status.codes = createStatusCodeList(codes)
+
+// status codes for redirects
+status.redirect = {
+  300: true,
+  301: true,
+  302: true,
+  303: true,
+  305: true,
+  307: true,
+  308: true
+}
+
+// status codes for empty bodies
+status.empty = {
+  204: true,
+  205: true,
+  304: true
+}
+
+// status codes for when you should retry the request
+status.retry = {
+  502: true,
+  503: true,
+  504: true
+}
+
+/**
+ * Create a map of message to status code.
+ * @private
+ */
+
+function createMessageToStatusCodeMap (codes) {
+  var map = {}
+
+  Object.keys(codes).forEach(function forEachCode (code) {
+    var message = codes[code]
+    var status = Number(code)
+
+    // populate map
+    map[message.toLowerCase()] = status
+  })
+
+  return map
+}
+
+/**
+ * Create a list of all status codes.
+ * @private
+ */
+
+function createStatusCodeList (codes) {
+  return Object.keys(codes).map(function mapCode (code) {
+    return Number(code)
+  })
+}
+
+/**
+ * Get the status code for given message.
+ * @private
+ */
+
+function getStatusCode (message) {
+  var msg = message.toLowerCase()
+
+  if (!Object.prototype.hasOwnProperty.call(status.code, msg)) {
+    throw new Error('invalid status message: "' + message + '"')
+  }
+
+  return status.code[msg]
+}
+
+/**
+ * Get the status message for given code.
+ * @private
+ */
+
+function getStatusMessage (code) {
+  if (!Object.prototype.hasOwnProperty.call(status.message, code)) {
+    throw new Error('invalid status code: ' + code)
+  }
+
+  return status.message[code]
+}
+
+/**
+ * Get the status code.
+ *
+ * Given a number, this will throw if it is not a known status
+ * code, otherwise the code will be returned. Given a string,
+ * the string will be parsed for a number and return the code
+ * if valid, otherwise will lookup the code assuming this is
+ * the status message.
+ *
+ * @param {string|number} code
+ * @returns {number}
+ * @public
+ */
+
+function status (code) {
+  if (typeof code === 'number') {
+    return getStatusMessage(code)
+  }
+
+  if (typeof code !== 'string') {
+    throw new TypeError('code must be a number or string')
+  }
+
+  // '403'
+  var n = parseInt(code, 10)
+  if (!isNaN(n)) {
+    return getStatusMessage(n)
+  }
+
+  return getStatusCode(code)
+}
diff --git a/server/node_modules/statuses/package.json b/server/node_modules/statuses/package.json
new file mode 100644
index 0000000..b5d016e
--- /dev/null
+++ b/server/node_modules/statuses/package.json
@@ -0,0 +1,49 @@
+{
+  "name": "statuses",
+  "description": "HTTP status utility",
+  "version": "2.0.2",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "repository": "jshttp/statuses",
+  "license": "MIT",
+  "keywords": [
+    "http",
+    "status",
+    "code"
+  ],
+  "files": [
+    "HISTORY.md",
+    "index.js",
+    "codes.json",
+    "LICENSE"
+  ],
+  "devDependencies": {
+    "csv-parse": "4.16.3",
+    "eslint": "7.19.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.31.0",
+    "eslint-plugin-markdown": "1.0.2",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "4.3.1",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "8.4.0",
+    "nyc": "15.1.0",
+    "raw-body": "2.5.2",
+    "stream-to-array": "2.3.0"
+  },
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "build": "node scripts/build.js",
+    "fetch": "node scripts/fetch-apache.js && node scripts/fetch-iana.js && node scripts/fetch-nginx.js && node scripts/fetch-node.js",
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec --check-leaks --bail test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "update": "npm run fetch && npm run build",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  }
+}
diff --git a/server/node_modules/streamsearch/.eslintrc.js b/server/node_modules/streamsearch/.eslintrc.js
new file mode 100644
index 0000000..be9311d
--- /dev/null
+++ b/server/node_modules/streamsearch/.eslintrc.js
@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = {
+  extends: '@mscdex/eslint-config',
+};
diff --git a/server/node_modules/streamsearch/.github/workflows/ci.yml b/server/node_modules/streamsearch/.github/workflows/ci.yml
new file mode 100644
index 0000000..29d5178
--- /dev/null
+++ b/server/node_modules/streamsearch/.github/workflows/ci.yml
@@ -0,0 +1,24 @@
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches: [ master ]
+
+jobs:
+  tests-linux:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version: [10.x, 12.x, 14.x, 16.x]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+      - name: Install module
+        run: npm install
+      - name: Run tests
+        run: npm test
diff --git a/server/node_modules/streamsearch/.github/workflows/lint.yml b/server/node_modules/streamsearch/.github/workflows/lint.yml
new file mode 100644
index 0000000..9f9e1f5
--- /dev/null
+++ b/server/node_modules/streamsearch/.github/workflows/lint.yml
@@ -0,0 +1,23 @@
+name: lint
+
+on:
+  pull_request:
+  push:
+    branches: [ master ]
+
+env:
+  NODE_VERSION: 16.x
+
+jobs:
+  lint-js:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js ${{ env.NODE_VERSION }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ env.NODE_VERSION }}
+      - name: Install ESLint + ESLint configs/plugins
+        run: npm install --only=dev
+      - name: Lint files
+        run: npm run lint
diff --git a/server/node_modules/streamsearch/LICENSE b/server/node_modules/streamsearch/LICENSE
new file mode 100644
index 0000000..9ea90e0
--- /dev/null
+++ b/server/node_modules/streamsearch/LICENSE
@@ -0,0 +1,19 @@
+Copyright Brian White. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/streamsearch/README.md b/server/node_modules/streamsearch/README.md
new file mode 100644
index 0000000..c3934d1
--- /dev/null
+++ b/server/node_modules/streamsearch/README.md
@@ -0,0 +1,95 @@
+Description
+===========
+
+streamsearch is a module for [node.js](http://nodejs.org/) that allows searching a stream using the Boyer-Moore-Horspool algorithm.
+
+This module is based heavily on the Streaming Boyer-Moore-Horspool C++ implementation by Hongli Lai [here](https://github.com/FooBarWidget/boyer-moore-horspool).
+
+
+Requirements
+============
+
+* [node.js](http://nodejs.org/) -- v10.0.0 or newer
+
+
+Installation
+============
+
+    npm install streamsearch
+
+Example
+=======
+
+```js
+  const { inspect } = require('util');
+
+  const StreamSearch = require('streamsearch');
+
+  const needle = Buffer.from('\r\n');
+  const ss = new StreamSearch(needle, (isMatch, data, start, end) => {
+    if (data)
+      console.log('data: ' + inspect(data.toString('latin1', start, end)));
+    if (isMatch)
+      console.log('match!');
+  });
+
+  const chunks = [
+    'foo',
+    ' bar',
+    '\r',
+    '\n',
+    'baz, hello\r',
+    '\n world.',
+    '\r\n Node.JS rules!!\r\n\r\n',
+  ];
+  for (const chunk of chunks)
+    ss.push(Buffer.from(chunk));
+
+  // output:
+  //
+  // data: 'foo'
+  // data: ' bar'
+  // match!
+  // data: 'baz, hello'
+  // match!
+  // data: ' world.'
+  // match!
+  // data: ' Node.JS rules!!'
+  // match!
+  // data: ''
+  // match!
+```
+
+
+API
+===
+
+Properties
+----------
+
+* **maxMatches** - < _integer_ > - The maximum number of matches. Defaults to `Infinity`.
+
+* **matches** - < _integer_ > - The current match count.
+
+
+Functions
+---------
+
+* **(constructor)**(< _mixed_ >needle, < _function_ >callback) - Creates and returns a new instance for searching for a _Buffer_ or _string_ `needle`. `callback` is called any time there is non-matching data and/or there is a needle match. `callback` will be called with the following arguments:
+
+  1. `isMatch` - _boolean_ - Indicates whether a match has been found
+
+  2. `data` - _mixed_ - If set, this contains data that did not match the needle.
+
+  3. `start` - _integer_ - The index in `data` where the non-matching data begins (inclusive).
+
+  4. `end` - _integer_ - The index in `data` where the non-matching data ends (exclusive).
+
+  5. `isSafeData` - _boolean_ - Indicates if it is safe to store a reference to `data` (e.g. as-is or via `data.slice()`) or not, as in some cases `data` may point to a Buffer whose contents change over time.
+
+* **destroy**() - _(void)_ - Emits any last remaining unmatched data that may still be buffered and then resets internal state.
+
+* **push**(< _Buffer_ >chunk) - _integer_ - Processes `chunk`, searching for a match. The return value is the last processed index in `chunk` + 1.
+
+* **reset**() - _(void)_ - Resets internal state. Useful for when you wish to start searching a new/different stream for example.
+
diff --git a/server/node_modules/streamsearch/lib/sbmh.js b/server/node_modules/streamsearch/lib/sbmh.js
new file mode 100644
index 0000000..510cae2
--- /dev/null
+++ b/server/node_modules/streamsearch/lib/sbmh.js
@@ -0,0 +1,267 @@
+'use strict';
+/*
+  Based heavily on the Streaming Boyer-Moore-Horspool C++ implementation
+  by Hongli Lai at: https://github.com/FooBarWidget/boyer-moore-horspool
+*/
+function memcmp(buf1, pos1, buf2, pos2, num) {
+  for (let i = 0; i < num; ++i) {
+    if (buf1[pos1 + i] !== buf2[pos2 + i])
+      return false;
+  }
+  return true;
+}
+
+class SBMH {
+  constructor(needle, cb) {
+    if (typeof cb !== 'function')
+      throw new Error('Missing match callback');
+
+    if (typeof needle === 'string')
+      needle = Buffer.from(needle);
+    else if (!Buffer.isBuffer(needle))
+      throw new Error(`Expected Buffer for needle, got ${typeof needle}`);
+
+    const needleLen = needle.length;
+
+    this.maxMatches = Infinity;
+    this.matches = 0;
+
+    this._cb = cb;
+    this._lookbehindSize = 0;
+    this._needle = needle;
+    this._bufPos = 0;
+
+    this._lookbehind = Buffer.allocUnsafe(needleLen);
+
+    // Initialize occurrence table.
+    this._occ = [
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen, needleLen, needleLen,
+      needleLen, needleLen, needleLen, needleLen
+    ];
+
+    // Populate occurrence table with analysis of the needle, ignoring the last
+    // letter.
+    if (needleLen > 1) {
+      for (let i = 0; i < needleLen - 1; ++i)
+        this._occ[needle[i]] = needleLen - 1 - i;
+    }
+  }
+
+  reset() {
+    this.matches = 0;
+    this._lookbehindSize = 0;
+    this._bufPos = 0;
+  }
+
+  push(chunk, pos) {
+    let result;
+    if (!Buffer.isBuffer(chunk))
+      chunk = Buffer.from(chunk, 'latin1');
+    const chunkLen = chunk.length;
+    this._bufPos = pos || 0;
+    while (result !== chunkLen && this.matches < this.maxMatches)
+      result = feed(this, chunk);
+    return result;
+  }
+
+  destroy() {
+    const lbSize = this._lookbehindSize;
+    if (lbSize)
+      this._cb(false, this._lookbehind, 0, lbSize, false);
+    this.reset();
+  }
+}
+
+function feed(self, data) {
+  const len = data.length;
+  const needle = self._needle;
+  const needleLen = needle.length;
+
+  // Positive: points to a position in `data`
+  //           pos == 3 points to data[3]
+  // Negative: points to a position in the lookbehind buffer
+  //           pos == -2 points to lookbehind[lookbehindSize - 2]
+  let pos = -self._lookbehindSize;
+  const lastNeedleCharPos = needleLen - 1;
+  const lastNeedleChar = needle[lastNeedleCharPos];
+  const end = len - needleLen;
+  const occ = self._occ;
+  const lookbehind = self._lookbehind;
+
+  if (pos < 0) {
+    // Lookbehind buffer is not empty. Perform Boyer-Moore-Horspool
+    // search with character lookup code that considers both the
+    // lookbehind buffer and the current round's haystack data.
+    //
+    // Loop until
+    //   there is a match.
+    // or until
+    //   we've moved past the position that requires the
+    //   lookbehind buffer. In this case we switch to the
+    //   optimized loop.
+    // or until
+    //   the character to look at lies outside the haystack.
+    while (pos < 0 && pos <= end) {
+      const nextPos = pos + lastNeedleCharPos;
+      const ch = (nextPos < 0
+                  ? lookbehind[self._lookbehindSize + nextPos]
+                  : data[nextPos]);
+
+      if (ch === lastNeedleChar
+          && matchNeedle(self, data, pos, lastNeedleCharPos)) {
+        self._lookbehindSize = 0;
+        ++self.matches;
+        if (pos > -self._lookbehindSize)
+          self._cb(true, lookbehind, 0, self._lookbehindSize + pos, false);
+        else
+          self._cb(true, undefined, 0, 0, true);
+
+        return (self._bufPos = pos + needleLen);
+      }
+
+      pos += occ[ch];
+    }
+
+    // No match.
+
+    // There's too few data for Boyer-Moore-Horspool to run,
+    // so let's use a different algorithm to skip as much as
+    // we can.
+    // Forward pos until
+    //   the trailing part of lookbehind + data
+    //   looks like the beginning of the needle
+    // or until
+    //   pos == 0
+    while (pos < 0 && !matchNeedle(self, data, pos, len - pos))
+      ++pos;
+
+    if (pos < 0) {
+      // Cut off part of the lookbehind buffer that has
+      // been processed and append the entire haystack
+      // into it.
+      const bytesToCutOff = self._lookbehindSize + pos;
+
+      if (bytesToCutOff > 0) {
+        // The cut off data is guaranteed not to contain the needle.
+        self._cb(false, lookbehind, 0, bytesToCutOff, false);
+      }
+
+      self._lookbehindSize -= bytesToCutOff;
+      lookbehind.copy(lookbehind, 0, bytesToCutOff, self._lookbehindSize);
+      lookbehind.set(data, self._lookbehindSize);
+      self._lookbehindSize += len;
+
+      self._bufPos = len;
+      return len;
+    }
+
+    // Discard lookbehind buffer.
+    self._cb(false, lookbehind, 0, self._lookbehindSize, false);
+    self._lookbehindSize = 0;
+  }
+
+  pos += self._bufPos;
+
+  const firstNeedleChar = needle[0];
+
+  // Lookbehind buffer is now empty. Perform Boyer-Moore-Horspool
+  // search with optimized character lookup code that only considers
+  // the current round's haystack data.
+  while (pos <= end) {
+    const ch = data[pos + lastNeedleCharPos];
+
+    if (ch === lastNeedleChar
+        && data[pos] === firstNeedleChar
+        && memcmp(needle, 0, data, pos, lastNeedleCharPos)) {
+      ++self.matches;
+      if (pos > 0)
+        self._cb(true, data, self._bufPos, pos, true);
+      else
+        self._cb(true, undefined, 0, 0, true);
+
+      return (self._bufPos = pos + needleLen);
+    }
+
+    pos += occ[ch];
+  }
+
+  // There was no match. If there's trailing haystack data that we cannot
+  // match yet using the Boyer-Moore-Horspool algorithm (because the trailing
+  // data is less than the needle size) then match using a modified
+  // algorithm that starts matching from the beginning instead of the end.
+  // Whatever trailing data is left after running this algorithm is added to
+  // the lookbehind buffer.
+  while (pos < len) {
+    if (data[pos] !== firstNeedleChar
+        || !memcmp(data, pos, needle, 0, len - pos)) {
+      ++pos;
+      continue;
+    }
+    data.copy(lookbehind, 0, pos, len);
+    self._lookbehindSize = len - pos;
+    break;
+  }
+
+  // Everything until `pos` is guaranteed not to contain needle data.
+  if (pos > 0)
+    self._cb(false, data, self._bufPos, pos < len ? pos : len, true);
+
+  self._bufPos = len;
+  return len;
+}
+
+function matchNeedle(self, data, pos, len) {
+  const lb = self._lookbehind;
+  const lbSize = self._lookbehindSize;
+  const needle = self._needle;
+
+  for (let i = 0; i < len; ++i, ++pos) {
+    const ch = (pos < 0 ? lb[lbSize + pos] : data[pos]);
+    if (ch !== needle[i])
+      return false;
+  }
+  return true;
+}
+
+module.exports = SBMH;
diff --git a/server/node_modules/streamsearch/package.json b/server/node_modules/streamsearch/package.json
new file mode 100644
index 0000000..51df8f9
--- /dev/null
+++ b/server/node_modules/streamsearch/package.json
@@ -0,0 +1,34 @@
+{
+  "name": "streamsearch",
+  "version": "1.1.0",
+  "author": "Brian White <mscdex@mscdex.net>",
+  "description": "Streaming Boyer-Moore-Horspool searching for node.js",
+  "main": "./lib/sbmh.js",
+  "engines": {
+    "node": ">=10.0.0"
+  },
+  "devDependencies": {
+    "@mscdex/eslint-config": "^1.1.0",
+    "eslint": "^7.32.0"
+  },
+  "scripts": {
+    "test": "node test/test.js",
+    "lint": "eslint --cache --report-unused-disable-directives --ext=.js .eslintrc.js lib test",
+    "lint:fix": "npm run lint -- --fix"
+  },
+  "keywords": [
+    "stream",
+    "horspool",
+    "boyer-moore-horspool",
+    "boyer-moore",
+    "search"
+  ],
+  "licenses": [{
+    "type": "MIT",
+    "url": "http://github.com/mscdex/streamsearch/raw/master/LICENSE"
+  }],
+  "repository": {
+    "type": "git",
+    "url": "http://github.com/mscdex/streamsearch.git"
+  }
+}
diff --git a/server/node_modules/streamsearch/test/test.js b/server/node_modules/streamsearch/test/test.js
new file mode 100644
index 0000000..39a04d7
--- /dev/null
+++ b/server/node_modules/streamsearch/test/test.js
@@ -0,0 +1,70 @@
+'use strict';
+
+const assert = require('assert');
+
+const StreamSearch = require('../lib/sbmh.js');
+
+[
+  {
+    needle: '\r\n',
+    chunks: [
+      'foo',
+      ' bar',
+      '\r',
+      '\n',
+      'baz, hello\r',
+      '\n world.',
+      '\r\n Node.JS rules!!\r\n\r\n',
+    ],
+    expect: [
+      [false, 'foo'],
+      [false, ' bar'],
+      [ true, null],
+      [false, 'baz, hello'],
+      [ true, null],
+      [false, ' world.'],
+      [ true, null],
+      [ true, ' Node.JS rules!!'],
+      [ true, ''],
+    ],
+  },
+  {
+    needle: '---foobarbaz',
+    chunks: [
+      '---foobarbaz',
+      'asdf',
+      '\r\n',
+      '---foobarba',
+      '---foobar',
+      'ba',
+      '\r\n---foobarbaz--\r\n',
+    ],
+    expect: [
+      [ true, null],
+      [false, 'asdf'],
+      [false, '\r\n'],
+      [false, '---foobarba'],
+      [false, '---foobarba'],
+      [ true, '\r\n'],
+      [false, '--\r\n'],
+    ],
+  },
+].forEach((test, i) => {
+  console.log(`Running test #${i + 1}`);
+  const { needle, chunks, expect } = test;
+
+  const results = [];
+  const ss = new StreamSearch(Buffer.from(needle),
+                              (isMatch, data, start, end) => {
+    if (data)
+      data = data.toString('latin1', start, end);
+    else
+      data = null;
+    results.push([isMatch, data]);
+  });
+
+  for (const chunk of chunks)
+    ss.push(Buffer.from(chunk));
+
+  assert.deepStrictEqual(results, expect);
+});
diff --git a/server/node_modules/string-width/index.d.ts b/server/node_modules/string-width/index.d.ts
new file mode 100644
index 0000000..12b5309
--- /dev/null
+++ b/server/node_modules/string-width/index.d.ts
@@ -0,0 +1,29 @@
+declare const stringWidth: {
+	/**
+	Get the visual width of a string - the number of columns required to display it.
+
+	Some Unicode characters are [fullwidth](https://en.wikipedia.org/wiki/Halfwidth_and_fullwidth_forms) and use double the normal width. [ANSI escape codes](https://en.wikipedia.org/wiki/ANSI_escape_code) are stripped and doesn't affect the width.
+
+	@example
+	```
+	import stringWidth = require('string-width');
+
+	stringWidth('a');
+	//=> 1
+
+	stringWidth('古');
+	//=> 2
+
+	stringWidth('\u001B[1m古\u001B[22m');
+	//=> 2
+	```
+	*/
+	(string: string): number;
+
+	// TODO: remove this in the next major version, refactor the whole definition to:
+	// declare function stringWidth(string: string): number;
+	// export = stringWidth;
+	default: typeof stringWidth;
+}
+
+export = stringWidth;
diff --git a/server/node_modules/string-width/index.js b/server/node_modules/string-width/index.js
new file mode 100644
index 0000000..f4d261a
--- /dev/null
+++ b/server/node_modules/string-width/index.js
@@ -0,0 +1,47 @@
+'use strict';
+const stripAnsi = require('strip-ansi');
+const isFullwidthCodePoint = require('is-fullwidth-code-point');
+const emojiRegex = require('emoji-regex');
+
+const stringWidth = string => {
+	if (typeof string !== 'string' || string.length === 0) {
+		return 0;
+	}
+
+	string = stripAnsi(string);
+
+	if (string.length === 0) {
+		return 0;
+	}
+
+	string = string.replace(emojiRegex(), '  ');
+
+	let width = 0;
+
+	for (let i = 0; i < string.length; i++) {
+		const code = string.codePointAt(i);
+
+		// Ignore control characters
+		if (code <= 0x1F || (code >= 0x7F && code <= 0x9F)) {
+			continue;
+		}
+
+		// Ignore combining characters
+		if (code >= 0x300 && code <= 0x36F) {
+			continue;
+		}
+
+		// Surrogates
+		if (code > 0xFFFF) {
+			i++;
+		}
+
+		width += isFullwidthCodePoint(code) ? 2 : 1;
+	}
+
+	return width;
+};
+
+module.exports = stringWidth;
+// TODO: remove this in the next major version
+module.exports.default = stringWidth;
diff --git a/server/node_modules/string-width/license b/server/node_modules/string-width/license
new file mode 100644
index 0000000..e7af2f7
--- /dev/null
+++ b/server/node_modules/string-width/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/string-width/package.json b/server/node_modules/string-width/package.json
new file mode 100644
index 0000000..28ba7b4
--- /dev/null
+++ b/server/node_modules/string-width/package.json
@@ -0,0 +1,56 @@
+{
+	"name": "string-width",
+	"version": "4.2.3",
+	"description": "Get the visual width of a string - the number of columns required to display it",
+	"license": "MIT",
+	"repository": "sindresorhus/string-width",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=8"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"string",
+		"character",
+		"unicode",
+		"width",
+		"visual",
+		"column",
+		"columns",
+		"fullwidth",
+		"full-width",
+		"full",
+		"ansi",
+		"escape",
+		"codes",
+		"cli",
+		"command-line",
+		"terminal",
+		"console",
+		"cjk",
+		"chinese",
+		"japanese",
+		"korean",
+		"fixed-width"
+	],
+	"dependencies": {
+		"emoji-regex": "^8.0.0",
+		"is-fullwidth-code-point": "^3.0.0",
+		"strip-ansi": "^6.0.1"
+	},
+	"devDependencies": {
+		"ava": "^1.4.1",
+		"tsd": "^0.7.1",
+		"xo": "^0.24.0"
+	}
+}
diff --git a/server/node_modules/string-width/readme.md b/server/node_modules/string-width/readme.md
new file mode 100644
index 0000000..bdd3141
--- /dev/null
+++ b/server/node_modules/string-width/readme.md
@@ -0,0 +1,50 @@
+# string-width
+
+> Get the visual width of a string - the number of columns required to display it
+
+Some Unicode characters are [fullwidth](https://en.wikipedia.org/wiki/Halfwidth_and_fullwidth_forms) and use double the normal width. [ANSI escape codes](https://en.wikipedia.org/wiki/ANSI_escape_code) are stripped and doesn't affect the width.
+
+Useful to be able to measure the actual width of command-line output.
+
+
+## Install
+
+```
+$ npm install string-width
+```
+
+
+## Usage
+
+```js
+const stringWidth = require('string-width');
+
+stringWidth('a');
+//=> 1
+
+stringWidth('古');
+//=> 2
+
+stringWidth('\u001B[1m古\u001B[22m');
+//=> 2
+```
+
+
+## Related
+
+- [string-width-cli](https://github.com/sindresorhus/string-width-cli) - CLI for this module
+- [string-length](https://github.com/sindresorhus/string-length) - Get the real length of a string
+- [widest-line](https://github.com/sindresorhus/widest-line) - Get the visual width of the widest line in a string
+
+
+---
+
+<div align="center">
+	<b>
+		<a href="https://tidelift.com/subscription/pkg/npm-string-width?utm_source=npm-string-width&utm_medium=referral&utm_campaign=readme">Get professional support for this package with a Tidelift subscription</a>
+	</b>
+	<br>
+	<sub>
+		Tidelift helps make open source sustainable for maintainers while giving companies<br>assurances about security, maintenance, and licensing for their dependencies.
+	</sub>
+</div>
diff --git a/server/node_modules/string_decoder/.travis.yml b/server/node_modules/string_decoder/.travis.yml
new file mode 100644
index 0000000..3347a72
--- /dev/null
+++ b/server/node_modules/string_decoder/.travis.yml
@@ -0,0 +1,50 @@
+sudo: false
+language: node_js
+before_install:
+  - npm install -g npm@2
+  - test $NPM_LEGACY && npm install -g npm@latest-3 || npm install npm -g
+notifications:
+  email: false
+matrix:
+  fast_finish: true
+  include:
+  - node_js: '0.8'
+    env:
+      - TASK=test
+      - NPM_LEGACY=true
+  - node_js: '0.10'
+    env:
+      - TASK=test
+      - NPM_LEGACY=true
+  - node_js: '0.11'
+    env:
+      - TASK=test
+      - NPM_LEGACY=true
+  - node_js: '0.12'
+    env:
+      - TASK=test
+      - NPM_LEGACY=true
+  - node_js: 1
+    env:
+      - TASK=test
+      - NPM_LEGACY=true
+  - node_js: 2
+    env:
+      - TASK=test
+      - NPM_LEGACY=true
+  - node_js: 3
+    env:
+      - TASK=test
+      - NPM_LEGACY=true
+  - node_js: 4
+    env: TASK=test
+  - node_js: 5
+    env: TASK=test
+  - node_js: 6
+    env: TASK=test
+  - node_js: 7
+    env: TASK=test
+  - node_js: 8
+    env: TASK=test
+  - node_js: 9
+    env: TASK=test
diff --git a/server/node_modules/string_decoder/LICENSE b/server/node_modules/string_decoder/LICENSE
new file mode 100644
index 0000000..778edb2
--- /dev/null
+++ b/server/node_modules/string_decoder/LICENSE
@@ -0,0 +1,48 @@
+Node.js is licensed for use as follows:
+
+"""
+Copyright Node.js contributors. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
+
+This license applies to parts of Node.js originating from the
+https://github.com/joyent/node repository:
+
+"""
+Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
+
diff --git a/server/node_modules/string_decoder/README.md b/server/node_modules/string_decoder/README.md
new file mode 100644
index 0000000..5fd5831
--- /dev/null
+++ b/server/node_modules/string_decoder/README.md
@@ -0,0 +1,47 @@
+# string_decoder
+
+***Node-core v8.9.4 string_decoder for userland***
+
+
+[![NPM](https://nodei.co/npm/string_decoder.png?downloads=true&downloadRank=true)](https://nodei.co/npm/string_decoder/)
+[![NPM](https://nodei.co/npm-dl/string_decoder.png?&months=6&height=3)](https://nodei.co/npm/string_decoder/)
+
+
+```bash
+npm install --save string_decoder
+```
+
+***Node-core string_decoder for userland***
+
+This package is a mirror of the string_decoder implementation in Node-core.
+
+Full documentation may be found on the [Node.js website](https://nodejs.org/dist/v8.9.4/docs/api/).
+
+As of version 1.0.0 **string_decoder** uses semantic versioning.
+
+## Previous versions
+
+Previous version numbers match the versions found in Node core, e.g. 0.10.24 matches Node 0.10.24, likewise 0.11.10 matches Node 0.11.10.
+
+## Update
+
+The *build/* directory contains a build script that will scrape the source from the [nodejs/node](https://github.com/nodejs/node) repo given a specific Node version.
+
+## Streams Working Group
+
+`string_decoder` is maintained by the Streams Working Group, which
+oversees the development and maintenance of the Streams API within
+Node.js. The responsibilities of the Streams Working Group include:
+
+* Addressing stream issues on the Node.js issue tracker.
+* Authoring and editing stream documentation within the Node.js project.
+* Reviewing changes to stream subclasses within the Node.js project.
+* Redirecting changes to streams from the Node.js project to this
+  project.
+* Assisting in the implementation of stream providers within Node.js.
+* Recommending versions of `readable-stream` to be included in Node.js.
+* Messaging about the future of streams to give the community advance
+  notice of changes.
+
+See [readable-stream](https://github.com/nodejs/readable-stream) for
+more details.
diff --git a/server/node_modules/string_decoder/lib/string_decoder.js b/server/node_modules/string_decoder/lib/string_decoder.js
new file mode 100644
index 0000000..2e89e63
--- /dev/null
+++ b/server/node_modules/string_decoder/lib/string_decoder.js
@@ -0,0 +1,296 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+
+/*<replacement>*/
+
+var Buffer = require('safe-buffer').Buffer;
+/*</replacement>*/
+
+var isEncoding = Buffer.isEncoding || function (encoding) {
+  encoding = '' + encoding;
+  switch (encoding && encoding.toLowerCase()) {
+    case 'hex':case 'utf8':case 'utf-8':case 'ascii':case 'binary':case 'base64':case 'ucs2':case 'ucs-2':case 'utf16le':case 'utf-16le':case 'raw':
+      return true;
+    default:
+      return false;
+  }
+};
+
+function _normalizeEncoding(enc) {
+  if (!enc) return 'utf8';
+  var retried;
+  while (true) {
+    switch (enc) {
+      case 'utf8':
+      case 'utf-8':
+        return 'utf8';
+      case 'ucs2':
+      case 'ucs-2':
+      case 'utf16le':
+      case 'utf-16le':
+        return 'utf16le';
+      case 'latin1':
+      case 'binary':
+        return 'latin1';
+      case 'base64':
+      case 'ascii':
+      case 'hex':
+        return enc;
+      default:
+        if (retried) return; // undefined
+        enc = ('' + enc).toLowerCase();
+        retried = true;
+    }
+  }
+};
+
+// Do not cache `Buffer.isEncoding` when checking encoding names as some
+// modules monkey-patch it to support additional encodings
+function normalizeEncoding(enc) {
+  var nenc = _normalizeEncoding(enc);
+  if (typeof nenc !== 'string' && (Buffer.isEncoding === isEncoding || !isEncoding(enc))) throw new Error('Unknown encoding: ' + enc);
+  return nenc || enc;
+}
+
+// StringDecoder provides an interface for efficiently splitting a series of
+// buffers into a series of JS strings without breaking apart multi-byte
+// characters.
+exports.StringDecoder = StringDecoder;
+function StringDecoder(encoding) {
+  this.encoding = normalizeEncoding(encoding);
+  var nb;
+  switch (this.encoding) {
+    case 'utf16le':
+      this.text = utf16Text;
+      this.end = utf16End;
+      nb = 4;
+      break;
+    case 'utf8':
+      this.fillLast = utf8FillLast;
+      nb = 4;
+      break;
+    case 'base64':
+      this.text = base64Text;
+      this.end = base64End;
+      nb = 3;
+      break;
+    default:
+      this.write = simpleWrite;
+      this.end = simpleEnd;
+      return;
+  }
+  this.lastNeed = 0;
+  this.lastTotal = 0;
+  this.lastChar = Buffer.allocUnsafe(nb);
+}
+
+StringDecoder.prototype.write = function (buf) {
+  if (buf.length === 0) return '';
+  var r;
+  var i;
+  if (this.lastNeed) {
+    r = this.fillLast(buf);
+    if (r === undefined) return '';
+    i = this.lastNeed;
+    this.lastNeed = 0;
+  } else {
+    i = 0;
+  }
+  if (i < buf.length) return r ? r + this.text(buf, i) : this.text(buf, i);
+  return r || '';
+};
+
+StringDecoder.prototype.end = utf8End;
+
+// Returns only complete characters in a Buffer
+StringDecoder.prototype.text = utf8Text;
+
+// Attempts to complete a partial non-UTF-8 character using bytes from a Buffer
+StringDecoder.prototype.fillLast = function (buf) {
+  if (this.lastNeed <= buf.length) {
+    buf.copy(this.lastChar, this.lastTotal - this.lastNeed, 0, this.lastNeed);
+    return this.lastChar.toString(this.encoding, 0, this.lastTotal);
+  }
+  buf.copy(this.lastChar, this.lastTotal - this.lastNeed, 0, buf.length);
+  this.lastNeed -= buf.length;
+};
+
+// Checks the type of a UTF-8 byte, whether it's ASCII, a leading byte, or a
+// continuation byte. If an invalid byte is detected, -2 is returned.
+function utf8CheckByte(byte) {
+  if (byte <= 0x7F) return 0;else if (byte >> 5 === 0x06) return 2;else if (byte >> 4 === 0x0E) return 3;else if (byte >> 3 === 0x1E) return 4;
+  return byte >> 6 === 0x02 ? -1 : -2;
+}
+
+// Checks at most 3 bytes at the end of a Buffer in order to detect an
+// incomplete multi-byte UTF-8 character. The total number of bytes (2, 3, or 4)
+// needed to complete the UTF-8 character (if applicable) are returned.
+function utf8CheckIncomplete(self, buf, i) {
+  var j = buf.length - 1;
+  if (j < i) return 0;
+  var nb = utf8CheckByte(buf[j]);
+  if (nb >= 0) {
+    if (nb > 0) self.lastNeed = nb - 1;
+    return nb;
+  }
+  if (--j < i || nb === -2) return 0;
+  nb = utf8CheckByte(buf[j]);
+  if (nb >= 0) {
+    if (nb > 0) self.lastNeed = nb - 2;
+    return nb;
+  }
+  if (--j < i || nb === -2) return 0;
+  nb = utf8CheckByte(buf[j]);
+  if (nb >= 0) {
+    if (nb > 0) {
+      if (nb === 2) nb = 0;else self.lastNeed = nb - 3;
+    }
+    return nb;
+  }
+  return 0;
+}
+
+// Validates as many continuation bytes for a multi-byte UTF-8 character as
+// needed or are available. If we see a non-continuation byte where we expect
+// one, we "replace" the validated continuation bytes we've seen so far with
+// a single UTF-8 replacement character ('\ufffd'), to match v8's UTF-8 decoding
+// behavior. The continuation byte check is included three times in the case
+// where all of the continuation bytes for a character exist in the same buffer.
+// It is also done this way as a slight performance increase instead of using a
+// loop.
+function utf8CheckExtraBytes(self, buf, p) {
+  if ((buf[0] & 0xC0) !== 0x80) {
+    self.lastNeed = 0;
+    return '\ufffd';
+  }
+  if (self.lastNeed > 1 && buf.length > 1) {
+    if ((buf[1] & 0xC0) !== 0x80) {
+      self.lastNeed = 1;
+      return '\ufffd';
+    }
+    if (self.lastNeed > 2 && buf.length > 2) {
+      if ((buf[2] & 0xC0) !== 0x80) {
+        self.lastNeed = 2;
+        return '\ufffd';
+      }
+    }
+  }
+}
+
+// Attempts to complete a multi-byte UTF-8 character using bytes from a Buffer.
+function utf8FillLast(buf) {
+  var p = this.lastTotal - this.lastNeed;
+  var r = utf8CheckExtraBytes(this, buf, p);
+  if (r !== undefined) return r;
+  if (this.lastNeed <= buf.length) {
+    buf.copy(this.lastChar, p, 0, this.lastNeed);
+    return this.lastChar.toString(this.encoding, 0, this.lastTotal);
+  }
+  buf.copy(this.lastChar, p, 0, buf.length);
+  this.lastNeed -= buf.length;
+}
+
+// Returns all complete UTF-8 characters in a Buffer. If the Buffer ended on a
+// partial character, the character's bytes are buffered until the required
+// number of bytes are available.
+function utf8Text(buf, i) {
+  var total = utf8CheckIncomplete(this, buf, i);
+  if (!this.lastNeed) return buf.toString('utf8', i);
+  this.lastTotal = total;
+  var end = buf.length - (total - this.lastNeed);
+  buf.copy(this.lastChar, 0, end);
+  return buf.toString('utf8', i, end);
+}
+
+// For UTF-8, a replacement character is added when ending on a partial
+// character.
+function utf8End(buf) {
+  var r = buf && buf.length ? this.write(buf) : '';
+  if (this.lastNeed) return r + '\ufffd';
+  return r;
+}
+
+// UTF-16LE typically needs two bytes per character, but even if we have an even
+// number of bytes available, we need to check if we end on a leading/high
+// surrogate. In that case, we need to wait for the next two bytes in order to
+// decode the last character properly.
+function utf16Text(buf, i) {
+  if ((buf.length - i) % 2 === 0) {
+    var r = buf.toString('utf16le', i);
+    if (r) {
+      var c = r.charCodeAt(r.length - 1);
+      if (c >= 0xD800 && c <= 0xDBFF) {
+        this.lastNeed = 2;
+        this.lastTotal = 4;
+        this.lastChar[0] = buf[buf.length - 2];
+        this.lastChar[1] = buf[buf.length - 1];
+        return r.slice(0, -1);
+      }
+    }
+    return r;
+  }
+  this.lastNeed = 1;
+  this.lastTotal = 2;
+  this.lastChar[0] = buf[buf.length - 1];
+  return buf.toString('utf16le', i, buf.length - 1);
+}
+
+// For UTF-16LE we do not explicitly append special replacement characters if we
+// end on a partial character, we simply let v8 handle that.
+function utf16End(buf) {
+  var r = buf && buf.length ? this.write(buf) : '';
+  if (this.lastNeed) {
+    var end = this.lastTotal - this.lastNeed;
+    return r + this.lastChar.toString('utf16le', 0, end);
+  }
+  return r;
+}
+
+function base64Text(buf, i) {
+  var n = (buf.length - i) % 3;
+  if (n === 0) return buf.toString('base64', i);
+  this.lastNeed = 3 - n;
+  this.lastTotal = 3;
+  if (n === 1) {
+    this.lastChar[0] = buf[buf.length - 1];
+  } else {
+    this.lastChar[0] = buf[buf.length - 2];
+    this.lastChar[1] = buf[buf.length - 1];
+  }
+  return buf.toString('base64', i, buf.length - n);
+}
+
+function base64End(buf) {
+  var r = buf && buf.length ? this.write(buf) : '';
+  if (this.lastNeed) return r + this.lastChar.toString('base64', 0, 3 - this.lastNeed);
+  return r;
+}
+
+// Pass bytes on through for single-byte encodings (e.g. ascii, latin1, hex)
+function simpleWrite(buf) {
+  return buf.toString(this.encoding);
+}
+
+function simpleEnd(buf) {
+  return buf && buf.length ? this.write(buf) : '';
+}
\ No newline at end of file
diff --git a/server/node_modules/string_decoder/node_modules/safe-buffer/LICENSE b/server/node_modules/string_decoder/node_modules/safe-buffer/LICENSE
new file mode 100644
index 0000000..0c068ce
--- /dev/null
+++ b/server/node_modules/string_decoder/node_modules/safe-buffer/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Feross Aboukhadijeh
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/string_decoder/node_modules/safe-buffer/README.md b/server/node_modules/string_decoder/node_modules/safe-buffer/README.md
new file mode 100644
index 0000000..e9a81af
--- /dev/null
+++ b/server/node_modules/string_decoder/node_modules/safe-buffer/README.md
@@ -0,0 +1,584 @@
+# safe-buffer [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![downloads][downloads-image]][downloads-url] [![javascript style guide][standard-image]][standard-url]
+
+[travis-image]: https://img.shields.io/travis/feross/safe-buffer/master.svg
+[travis-url]: https://travis-ci.org/feross/safe-buffer
+[npm-image]: https://img.shields.io/npm/v/safe-buffer.svg
+[npm-url]: https://npmjs.org/package/safe-buffer
+[downloads-image]: https://img.shields.io/npm/dm/safe-buffer.svg
+[downloads-url]: https://npmjs.org/package/safe-buffer
+[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
+[standard-url]: https://standardjs.com
+
+#### Safer Node.js Buffer API
+
+**Use the new Node.js Buffer APIs (`Buffer.from`, `Buffer.alloc`,
+`Buffer.allocUnsafe`, `Buffer.allocUnsafeSlow`) in all versions of Node.js.**
+
+**Uses the built-in implementation when available.**
+
+## install
+
+```
+npm install safe-buffer
+```
+
+## usage
+
+The goal of this package is to provide a safe replacement for the node.js `Buffer`.
+
+It's a drop-in replacement for `Buffer`. You can use it by adding one `require` line to
+the top of your node.js modules:
+
+```js
+var Buffer = require('safe-buffer').Buffer
+
+// Existing buffer code will continue to work without issues:
+
+new Buffer('hey', 'utf8')
+new Buffer([1, 2, 3], 'utf8')
+new Buffer(obj)
+new Buffer(16) // create an uninitialized buffer (potentially unsafe)
+
+// But you can use these new explicit APIs to make clear what you want:
+
+Buffer.from('hey', 'utf8') // convert from many types to a Buffer
+Buffer.alloc(16) // create a zero-filled buffer (safe)
+Buffer.allocUnsafe(16) // create an uninitialized buffer (potentially unsafe)
+```
+
+## api
+
+### Class Method: Buffer.from(array)
+
+
+* `array` {Array}
+
+Allocates a new `Buffer` using an `array` of octets.
+
+```js
+const buf = Buffer.from([0x62,0x75,0x66,0x66,0x65,0x72]);
+  // creates a new Buffer containing ASCII bytes
+  // ['b','u','f','f','e','r']
+```
+
+A `TypeError` will be thrown if `array` is not an `Array`.
+
+### Class Method: Buffer.from(arrayBuffer[, byteOffset[, length]])
+
+
+* `arrayBuffer` {ArrayBuffer} The `.buffer` property of a `TypedArray` or
+  a `new ArrayBuffer()`
+* `byteOffset` {Number} Default: `0`
+* `length` {Number} Default: `arrayBuffer.length - byteOffset`
+
+When passed a reference to the `.buffer` property of a `TypedArray` instance,
+the newly created `Buffer` will share the same allocated memory as the
+TypedArray.
+
+```js
+const arr = new Uint16Array(2);
+arr[0] = 5000;
+arr[1] = 4000;
+
+const buf = Buffer.from(arr.buffer); // shares the memory with arr;
+
+console.log(buf);
+  // Prints: <Buffer 88 13 a0 0f>
+
+// changing the TypedArray changes the Buffer also
+arr[1] = 6000;
+
+console.log(buf);
+  // Prints: <Buffer 88 13 70 17>
+```
+
+The optional `byteOffset` and `length` arguments specify a memory range within
+the `arrayBuffer` that will be shared by the `Buffer`.
+
+```js
+const ab = new ArrayBuffer(10);
+const buf = Buffer.from(ab, 0, 2);
+console.log(buf.length);
+  // Prints: 2
+```
+
+A `TypeError` will be thrown if `arrayBuffer` is not an `ArrayBuffer`.
+
+### Class Method: Buffer.from(buffer)
+
+
+* `buffer` {Buffer}
+
+Copies the passed `buffer` data onto a new `Buffer` instance.
+
+```js
+const buf1 = Buffer.from('buffer');
+const buf2 = Buffer.from(buf1);
+
+buf1[0] = 0x61;
+console.log(buf1.toString());
+  // 'auffer'
+console.log(buf2.toString());
+  // 'buffer' (copy is not changed)
+```
+
+A `TypeError` will be thrown if `buffer` is not a `Buffer`.
+
+### Class Method: Buffer.from(str[, encoding])
+
+
+* `str` {String} String to encode.
+* `encoding` {String} Encoding to use, Default: `'utf8'`
+
+Creates a new `Buffer` containing the given JavaScript string `str`. If
+provided, the `encoding` parameter identifies the character encoding.
+If not provided, `encoding` defaults to `'utf8'`.
+
+```js
+const buf1 = Buffer.from('this is a tést');
+console.log(buf1.toString());
+  // prints: this is a tést
+console.log(buf1.toString('ascii'));
+  // prints: this is a tC)st
+
+const buf2 = Buffer.from('7468697320697320612074c3a97374', 'hex');
+console.log(buf2.toString());
+  // prints: this is a tést
+```
+
+A `TypeError` will be thrown if `str` is not a string.
+
+### Class Method: Buffer.alloc(size[, fill[, encoding]])
+
+
+* `size` {Number}
+* `fill` {Value} Default: `undefined`
+* `encoding` {String} Default: `utf8`
+
+Allocates a new `Buffer` of `size` bytes. If `fill` is `undefined`, the
+`Buffer` will be *zero-filled*.
+
+```js
+const buf = Buffer.alloc(5);
+console.log(buf);
+  // <Buffer 00 00 00 00 00>
+```
+
+The `size` must be less than or equal to the value of
+`require('buffer').kMaxLength` (on 64-bit architectures, `kMaxLength` is
+`(2^31)-1`). Otherwise, a [`RangeError`][] is thrown. A zero-length Buffer will
+be created if a `size` less than or equal to 0 is specified.
+
+If `fill` is specified, the allocated `Buffer` will be initialized by calling
+`buf.fill(fill)`. See [`buf.fill()`][] for more information.
+
+```js
+const buf = Buffer.alloc(5, 'a');
+console.log(buf);
+  // <Buffer 61 61 61 61 61>
+```
+
+If both `fill` and `encoding` are specified, the allocated `Buffer` will be
+initialized by calling `buf.fill(fill, encoding)`. For example:
+
+```js
+const buf = Buffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');
+console.log(buf);
+  // <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64>
+```
+
+Calling `Buffer.alloc(size)` can be significantly slower than the alternative
+`Buffer.allocUnsafe(size)` but ensures that the newly created `Buffer` instance
+contents will *never contain sensitive data*.
+
+A `TypeError` will be thrown if `size` is not a number.
+
+### Class Method: Buffer.allocUnsafe(size)
+
+
+* `size` {Number}
+
+Allocates a new *non-zero-filled* `Buffer` of `size` bytes.  The `size` must
+be less than or equal to the value of `require('buffer').kMaxLength` (on 64-bit
+architectures, `kMaxLength` is `(2^31)-1`). Otherwise, a [`RangeError`][] is
+thrown. A zero-length Buffer will be created if a `size` less than or equal to
+0 is specified.
+
+The underlying memory for `Buffer` instances created in this way is *not
+initialized*. The contents of the newly created `Buffer` are unknown and
+*may contain sensitive data*. Use [`buf.fill(0)`][] to initialize such
+`Buffer` instances to zeroes.
+
+```js
+const buf = Buffer.allocUnsafe(5);
+console.log(buf);
+  // <Buffer 78 e0 82 02 01>
+  // (octets will be different, every time)
+buf.fill(0);
+console.log(buf);
+  // <Buffer 00 00 00 00 00>
+```
+
+A `TypeError` will be thrown if `size` is not a number.
+
+Note that the `Buffer` module pre-allocates an internal `Buffer` instance of
+size `Buffer.poolSize` that is used as a pool for the fast allocation of new
+`Buffer` instances created using `Buffer.allocUnsafe(size)` (and the deprecated
+`new Buffer(size)` constructor) only when `size` is less than or equal to
+`Buffer.poolSize >> 1` (floor of `Buffer.poolSize` divided by two). The default
+value of `Buffer.poolSize` is `8192` but can be modified.
+
+Use of this pre-allocated internal memory pool is a key difference between
+calling `Buffer.alloc(size, fill)` vs. `Buffer.allocUnsafe(size).fill(fill)`.
+Specifically, `Buffer.alloc(size, fill)` will *never* use the internal Buffer
+pool, while `Buffer.allocUnsafe(size).fill(fill)` *will* use the internal
+Buffer pool if `size` is less than or equal to half `Buffer.poolSize`. The
+difference is subtle but can be important when an application requires the
+additional performance that `Buffer.allocUnsafe(size)` provides.
+
+### Class Method: Buffer.allocUnsafeSlow(size)
+
+
+* `size` {Number}
+
+Allocates a new *non-zero-filled* and non-pooled `Buffer` of `size` bytes.  The
+`size` must be less than or equal to the value of
+`require('buffer').kMaxLength` (on 64-bit architectures, `kMaxLength` is
+`(2^31)-1`). Otherwise, a [`RangeError`][] is thrown. A zero-length Buffer will
+be created if a `size` less than or equal to 0 is specified.
+
+The underlying memory for `Buffer` instances created in this way is *not
+initialized*. The contents of the newly created `Buffer` are unknown and
+*may contain sensitive data*. Use [`buf.fill(0)`][] to initialize such
+`Buffer` instances to zeroes.
+
+When using `Buffer.allocUnsafe()` to allocate new `Buffer` instances,
+allocations under 4KB are, by default, sliced from a single pre-allocated
+`Buffer`. This allows applications to avoid the garbage collection overhead of
+creating many individually allocated Buffers. This approach improves both
+performance and memory usage by eliminating the need to track and cleanup as
+many `Persistent` objects.
+
+However, in the case where a developer may need to retain a small chunk of
+memory from a pool for an indeterminate amount of time, it may be appropriate
+to create an un-pooled Buffer instance using `Buffer.allocUnsafeSlow()` then
+copy out the relevant bits.
+
+```js
+// need to keep around a few small chunks of memory
+const store = [];
+
+socket.on('readable', () => {
+  const data = socket.read();
+  // allocate for retained data
+  const sb = Buffer.allocUnsafeSlow(10);
+  // copy the data into the new allocation
+  data.copy(sb, 0, 0, 10);
+  store.push(sb);
+});
+```
+
+Use of `Buffer.allocUnsafeSlow()` should be used only as a last resort *after*
+a developer has observed undue memory retention in their applications.
+
+A `TypeError` will be thrown if `size` is not a number.
+
+### All the Rest
+
+The rest of the `Buffer` API is exactly the same as in node.js.
+[See the docs](https://nodejs.org/api/buffer.html).
+
+
+## Related links
+
+- [Node.js issue: Buffer(number) is unsafe](https://github.com/nodejs/node/issues/4660)
+- [Node.js Enhancement Proposal: Buffer.from/Buffer.alloc/Buffer.zalloc/Buffer() soft-deprecate](https://github.com/nodejs/node-eps/pull/4)
+
+## Why is `Buffer` unsafe?
+
+Today, the node.js `Buffer` constructor is overloaded to handle many different argument
+types like `String`, `Array`, `Object`, `TypedArrayView` (`Uint8Array`, etc.),
+`ArrayBuffer`, and also `Number`.
+
+The API is optimized for convenience: you can throw any type at it, and it will try to do
+what you want.
+
+Because the Buffer constructor is so powerful, you often see code like this:
+
+```js
+// Convert UTF-8 strings to hex
+function toHex (str) {
+  return new Buffer(str).toString('hex')
+}
+```
+
+***But what happens if `toHex` is called with a `Number` argument?***
+
+### Remote Memory Disclosure
+
+If an attacker can make your program call the `Buffer` constructor with a `Number`
+argument, then they can make it allocate uninitialized memory from the node.js process.
+This could potentially disclose TLS private keys, user data, or database passwords.
+
+When the `Buffer` constructor is passed a `Number` argument, it returns an
+**UNINITIALIZED** block of memory of the specified `size`. When you create a `Buffer` like
+this, you **MUST** overwrite the contents before returning it to the user.
+
+From the [node.js docs](https://nodejs.org/api/buffer.html#buffer_new_buffer_size):
+
+> `new Buffer(size)`
+>
+> - `size` Number
+>
+> The underlying memory for `Buffer` instances created in this way is not initialized.
+> **The contents of a newly created `Buffer` are unknown and could contain sensitive
+> data.** Use `buf.fill(0)` to initialize a Buffer to zeroes.
+
+(Emphasis our own.)
+
+Whenever the programmer intended to create an uninitialized `Buffer` you often see code
+like this:
+
+```js
+var buf = new Buffer(16)
+
+// Immediately overwrite the uninitialized buffer with data from another buffer
+for (var i = 0; i < buf.length; i++) {
+  buf[i] = otherBuf[i]
+}
+```
+
+
+### Would this ever be a problem in real code?
+
+Yes. It's surprisingly common to forget to check the type of your variables in a
+dynamically-typed language like JavaScript.
+
+Usually the consequences of assuming the wrong type is that your program crashes with an
+uncaught exception. But the failure mode for forgetting to check the type of arguments to
+the `Buffer` constructor is more catastrophic.
+
+Here's an example of a vulnerable service that takes a JSON payload and converts it to
+hex:
+
+```js
+// Take a JSON payload {str: "some string"} and convert it to hex
+var server = http.createServer(function (req, res) {
+  var data = ''
+  req.setEncoding('utf8')
+  req.on('data', function (chunk) {
+    data += chunk
+  })
+  req.on('end', function () {
+    var body = JSON.parse(data)
+    res.end(new Buffer(body.str).toString('hex'))
+  })
+})
+
+server.listen(8080)
+```
+
+In this example, an http client just has to send:
+
+```json
+{
+  "str": 1000
+}
+```
+
+and it will get back 1,000 bytes of uninitialized memory from the server.
+
+This is a very serious bug. It's similar in severity to the
+[the Heartbleed bug](http://heartbleed.com/) that allowed disclosure of OpenSSL process
+memory by remote attackers.
+
+
+### Which real-world packages were vulnerable?
+
+#### [`bittorrent-dht`](https://www.npmjs.com/package/bittorrent-dht)
+
+[Mathias Buus](https://github.com/mafintosh) and I
+([Feross Aboukhadijeh](http://feross.org/)) found this issue in one of our own packages,
+[`bittorrent-dht`](https://www.npmjs.com/package/bittorrent-dht). The bug would allow
+anyone on the internet to send a series of messages to a user of `bittorrent-dht` and get
+them to reveal 20 bytes at a time of uninitialized memory from the node.js process.
+
+Here's
+[the commit](https://github.com/feross/bittorrent-dht/commit/6c7da04025d5633699800a99ec3fbadf70ad35b8)
+that fixed it. We released a new fixed version, created a
+[Node Security Project disclosure](https://nodesecurity.io/advisories/68), and deprecated all
+vulnerable versions on npm so users will get a warning to upgrade to a newer version.
+
+#### [`ws`](https://www.npmjs.com/package/ws)
+
+That got us wondering if there were other vulnerable packages. Sure enough, within a short
+period of time, we found the same issue in [`ws`](https://www.npmjs.com/package/ws), the
+most popular WebSocket implementation in node.js.
+
+If certain APIs were called with `Number` parameters instead of `String` or `Buffer` as
+expected, then uninitialized server memory would be disclosed to the remote peer.
+
+These were the vulnerable methods:
+
+```js
+socket.send(number)
+socket.ping(number)
+socket.pong(number)
+```
+
+Here's a vulnerable socket server with some echo functionality:
+
+```js
+server.on('connection', function (socket) {
+  socket.on('message', function (message) {
+    message = JSON.parse(message)
+    if (message.type === 'echo') {
+      socket.send(message.data) // send back the user's message
+    }
+  })
+})
+```
+
+`socket.send(number)` called on the server, will disclose server memory.
+
+Here's [the release](https://github.com/websockets/ws/releases/tag/1.0.1) where the issue
+was fixed, with a more detailed explanation. Props to
+[Arnout Kazemier](https://github.com/3rd-Eden) for the quick fix. Here's the
+[Node Security Project disclosure](https://nodesecurity.io/advisories/67).
+
+
+### What's the solution?
+
+It's important that node.js offers a fast way to get memory otherwise performance-critical
+applications would needlessly get a lot slower.
+
+But we need a better way to *signal our intent* as programmers. **When we want
+uninitialized memory, we should request it explicitly.**
+
+Sensitive functionality should not be packed into a developer-friendly API that loosely
+accepts many different types. This type of API encourages the lazy practice of passing
+variables in without checking the type very carefully.
+
+#### A new API: `Buffer.allocUnsafe(number)`
+
+The functionality of creating buffers with uninitialized memory should be part of another
+API. We propose `Buffer.allocUnsafe(number)`. This way, it's not part of an API that
+frequently gets user input of all sorts of different types passed into it.
+
+```js
+var buf = Buffer.allocUnsafe(16) // careful, uninitialized memory!
+
+// Immediately overwrite the uninitialized buffer with data from another buffer
+for (var i = 0; i < buf.length; i++) {
+  buf[i] = otherBuf[i]
+}
+```
+
+
+### How do we fix node.js core?
+
+We sent [a PR to node.js core](https://github.com/nodejs/node/pull/4514) (merged as
+`semver-major`) which defends against one case:
+
+```js
+var str = 16
+new Buffer(str, 'utf8')
+```
+
+In this situation, it's implied that the programmer intended the first argument to be a
+string, since they passed an encoding as a second argument. Today, node.js will allocate
+uninitialized memory in the case of `new Buffer(number, encoding)`, which is probably not
+what the programmer intended.
+
+But this is only a partial solution, since if the programmer does `new Buffer(variable)`
+(without an `encoding` parameter) there's no way to know what they intended. If `variable`
+is sometimes a number, then uninitialized memory will sometimes be returned.
+
+### What's the real long-term fix?
+
+We could deprecate and remove `new Buffer(number)` and use `Buffer.allocUnsafe(number)` when
+we need uninitialized memory. But that would break 1000s of packages.
+
+~~We believe the best solution is to:~~
+
+~~1. Change `new Buffer(number)` to return safe, zeroed-out memory~~
+
+~~2. Create a new API for creating uninitialized Buffers. We propose: `Buffer.allocUnsafe(number)`~~
+
+#### Update
+
+We now support adding three new APIs:
+
+- `Buffer.from(value)` - convert from any type to a buffer
+- `Buffer.alloc(size)` - create a zero-filled buffer
+- `Buffer.allocUnsafe(size)` - create an uninitialized buffer with given size
+
+This solves the core problem that affected `ws` and `bittorrent-dht` which is
+`Buffer(variable)` getting tricked into taking a number argument.
+
+This way, existing code continues working and the impact on the npm ecosystem will be
+minimal. Over time, npm maintainers can migrate performance-critical code to use
+`Buffer.allocUnsafe(number)` instead of `new Buffer(number)`.
+
+
+### Conclusion
+
+We think there's a serious design issue with the `Buffer` API as it exists today. It
+promotes insecure software by putting high-risk functionality into a convenient API
+with friendly "developer ergonomics".
+
+This wasn't merely a theoretical exercise because we found the issue in some of the
+most popular npm packages.
+
+Fortunately, there's an easy fix that can be applied today. Use `safe-buffer` in place of
+`buffer`.
+
+```js
+var Buffer = require('safe-buffer').Buffer
+```
+
+Eventually, we hope that node.js core can switch to this new, safer behavior. We believe
+the impact on the ecosystem would be minimal since it's not a breaking change.
+Well-maintained, popular packages would be updated to use `Buffer.alloc` quickly, while
+older, insecure packages would magically become safe from this attack vector.
+
+
+## links
+
+- [Node.js PR: buffer: throw if both length and enc are passed](https://github.com/nodejs/node/pull/4514)
+- [Node Security Project disclosure for `ws`](https://nodesecurity.io/advisories/67)
+- [Node Security Project disclosure for`bittorrent-dht`](https://nodesecurity.io/advisories/68)
+
+
+## credit
+
+The original issues in `bittorrent-dht`
+([disclosure](https://nodesecurity.io/advisories/68)) and
+`ws` ([disclosure](https://nodesecurity.io/advisories/67)) were discovered by
+[Mathias Buus](https://github.com/mafintosh) and
+[Feross Aboukhadijeh](http://feross.org/).
+
+Thanks to [Adam Baldwin](https://github.com/evilpacket) for helping disclose these issues
+and for his work running the [Node Security Project](https://nodesecurity.io/).
+
+Thanks to [John Hiesey](https://github.com/jhiesey) for proofreading this README and
+auditing the code.
+
+
+## license
+
+MIT. Copyright (C) [Feross Aboukhadijeh](http://feross.org)
diff --git a/server/node_modules/string_decoder/node_modules/safe-buffer/index.d.ts b/server/node_modules/string_decoder/node_modules/safe-buffer/index.d.ts
new file mode 100644
index 0000000..e9fed80
--- /dev/null
+++ b/server/node_modules/string_decoder/node_modules/safe-buffer/index.d.ts
@@ -0,0 +1,187 @@
+declare module "safe-buffer" {
+  export class Buffer {
+    length: number
+    write(string: string, offset?: number, length?: number, encoding?: string): number;
+    toString(encoding?: string, start?: number, end?: number): string;
+    toJSON(): { type: 'Buffer', data: any[] };
+    equals(otherBuffer: Buffer): boolean;
+    compare(otherBuffer: Buffer, targetStart?: number, targetEnd?: number, sourceStart?: number, sourceEnd?: number): number;
+    copy(targetBuffer: Buffer, targetStart?: number, sourceStart?: number, sourceEnd?: number): number;
+    slice(start?: number, end?: number): Buffer;
+    writeUIntLE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeUIntBE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeIntLE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    writeIntBE(value: number, offset: number, byteLength: number, noAssert?: boolean): number;
+    readUIntLE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readUIntBE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readIntLE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readIntBE(offset: number, byteLength: number, noAssert?: boolean): number;
+    readUInt8(offset: number, noAssert?: boolean): number;
+    readUInt16LE(offset: number, noAssert?: boolean): number;
+    readUInt16BE(offset: number, noAssert?: boolean): number;
+    readUInt32LE(offset: number, noAssert?: boolean): number;
+    readUInt32BE(offset: number, noAssert?: boolean): number;
+    readInt8(offset: number, noAssert?: boolean): number;
+    readInt16LE(offset: number, noAssert?: boolean): number;
+    readInt16BE(offset: number, noAssert?: boolean): number;
+    readInt32LE(offset: number, noAssert?: boolean): number;
+    readInt32BE(offset: number, noAssert?: boolean): number;
+    readFloatLE(offset: number, noAssert?: boolean): number;
+    readFloatBE(offset: number, noAssert?: boolean): number;
+    readDoubleLE(offset: number, noAssert?: boolean): number;
+    readDoubleBE(offset: number, noAssert?: boolean): number;
+    swap16(): Buffer;
+    swap32(): Buffer;
+    swap64(): Buffer;
+    writeUInt8(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt16LE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt16BE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt32LE(value: number, offset: number, noAssert?: boolean): number;
+    writeUInt32BE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt8(value: number, offset: number, noAssert?: boolean): number;
+    writeInt16LE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt16BE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt32LE(value: number, offset: number, noAssert?: boolean): number;
+    writeInt32BE(value: number, offset: number, noAssert?: boolean): number;
+    writeFloatLE(value: number, offset: number, noAssert?: boolean): number;
+    writeFloatBE(value: number, offset: number, noAssert?: boolean): number;
+    writeDoubleLE(value: number, offset: number, noAssert?: boolean): number;
+    writeDoubleBE(value: number, offset: number, noAssert?: boolean): number;
+    fill(value: any, offset?: number, end?: number): this;
+    indexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
+    lastIndexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
+    includes(value: string | number | Buffer, byteOffset?: number, encoding?: string): boolean;
+
+    /**
+     * Allocates a new buffer containing the given {str}.
+     *
+     * @param str String to store in buffer.
+     * @param encoding encoding to use, optional.  Default is 'utf8'
+     */
+     constructor (str: string, encoding?: string);
+    /**
+     * Allocates a new buffer of {size} octets.
+     *
+     * @param size count of octets to allocate.
+     */
+    constructor (size: number);
+    /**
+     * Allocates a new buffer containing the given {array} of octets.
+     *
+     * @param array The octets to store.
+     */
+    constructor (array: Uint8Array);
+    /**
+     * Produces a Buffer backed by the same allocated memory as
+     * the given {ArrayBuffer}.
+     *
+     *
+     * @param arrayBuffer The ArrayBuffer with which to share memory.
+     */
+    constructor (arrayBuffer: ArrayBuffer);
+    /**
+     * Allocates a new buffer containing the given {array} of octets.
+     *
+     * @param array The octets to store.
+     */
+    constructor (array: any[]);
+    /**
+     * Copies the passed {buffer} data onto a new {Buffer} instance.
+     *
+     * @param buffer The buffer to copy.
+     */
+    constructor (buffer: Buffer);
+    prototype: Buffer;
+    /**
+     * Allocates a new Buffer using an {array} of octets.
+     *
+     * @param array
+     */
+    static from(array: any[]): Buffer;
+    /**
+     * When passed a reference to the .buffer property of a TypedArray instance,
+     * the newly created Buffer will share the same allocated memory as the TypedArray.
+     * The optional {byteOffset} and {length} arguments specify a memory range
+     * within the {arrayBuffer} that will be shared by the Buffer.
+     *
+     * @param arrayBuffer The .buffer property of a TypedArray or a new ArrayBuffer()
+     * @param byteOffset
+     * @param length
+     */
+    static from(arrayBuffer: ArrayBuffer, byteOffset?: number, length?: number): Buffer;
+    /**
+     * Copies the passed {buffer} data onto a new Buffer instance.
+     *
+     * @param buffer
+     */
+    static from(buffer: Buffer): Buffer;
+    /**
+     * Creates a new Buffer containing the given JavaScript string {str}.
+     * If provided, the {encoding} parameter identifies the character encoding.
+     * If not provided, {encoding} defaults to 'utf8'.
+     *
+     * @param str
+     */
+    static from(str: string, encoding?: string): Buffer;
+    /**
+     * Returns true if {obj} is a Buffer
+     *
+     * @param obj object to test.
+     */
+    static isBuffer(obj: any): obj is Buffer;
+    /**
+     * Returns true if {encoding} is a valid encoding argument.
+     * Valid string encodings in Node 0.12: 'ascii'|'utf8'|'utf16le'|'ucs2'(alias of 'utf16le')|'base64'|'binary'(deprecated)|'hex'
+     *
+     * @param encoding string to test.
+     */
+    static isEncoding(encoding: string): boolean;
+    /**
+     * Gives the actual byte length of a string. encoding defaults to 'utf8'.
+     * This is not the same as String.prototype.length since that returns the number of characters in a string.
+     *
+     * @param string string to test.
+     * @param encoding encoding used to evaluate (defaults to 'utf8')
+     */
+    static byteLength(string: string, encoding?: string): number;
+    /**
+     * Returns a buffer which is the result of concatenating all the buffers in the list together.
+     *
+     * If the list has no items, or if the totalLength is 0, then it returns a zero-length buffer.
+     * If the list has exactly one item, then the first item of the list is returned.
+     * If the list has more than one item, then a new Buffer is created.
+     *
+     * @param list An array of Buffer objects to concatenate
+     * @param totalLength Total length of the buffers when concatenated.
+     *   If totalLength is not provided, it is read from the buffers in the list. However, this adds an additional loop to the function, so it is faster to provide the length explicitly.
+     */
+    static concat(list: Buffer[], totalLength?: number): Buffer;
+    /**
+     * The same as buf1.compare(buf2).
+     */
+    static compare(buf1: Buffer, buf2: Buffer): number;
+    /**
+     * Allocates a new buffer of {size} octets.
+     *
+     * @param size count of octets to allocate.
+     * @param fill if specified, buffer will be initialized by calling buf.fill(fill).
+     *    If parameter is omitted, buffer will be filled with zeros.
+     * @param encoding encoding used for call to buf.fill while initalizing
+     */
+    static alloc(size: number, fill?: string | Buffer | number, encoding?: string): Buffer;
+    /**
+     * Allocates a new buffer of {size} octets, leaving memory not initialized, so the contents
+     * of the newly created Buffer are unknown and may contain sensitive data.
+     *
+     * @param size count of octets to allocate
+     */
+    static allocUnsafe(size: number): Buffer;
+    /**
+     * Allocates a new non-pooled buffer of {size} octets, leaving memory not initialized, so the contents
+     * of the newly created Buffer are unknown and may contain sensitive data.
+     *
+     * @param size count of octets to allocate
+     */
+    static allocUnsafeSlow(size: number): Buffer;
+  }
+}
\ No newline at end of file
diff --git a/server/node_modules/string_decoder/node_modules/safe-buffer/index.js b/server/node_modules/string_decoder/node_modules/safe-buffer/index.js
new file mode 100644
index 0000000..22438da
--- /dev/null
+++ b/server/node_modules/string_decoder/node_modules/safe-buffer/index.js
@@ -0,0 +1,62 @@
+/* eslint-disable node/no-deprecated-api */
+var buffer = require('buffer')
+var Buffer = buffer.Buffer
+
+// alternative to using Object.keys for old browsers
+function copyProps (src, dst) {
+  for (var key in src) {
+    dst[key] = src[key]
+  }
+}
+if (Buffer.from && Buffer.alloc && Buffer.allocUnsafe && Buffer.allocUnsafeSlow) {
+  module.exports = buffer
+} else {
+  // Copy properties from require('buffer')
+  copyProps(buffer, exports)
+  exports.Buffer = SafeBuffer
+}
+
+function SafeBuffer (arg, encodingOrOffset, length) {
+  return Buffer(arg, encodingOrOffset, length)
+}
+
+// Copy static methods from Buffer
+copyProps(Buffer, SafeBuffer)
+
+SafeBuffer.from = function (arg, encodingOrOffset, length) {
+  if (typeof arg === 'number') {
+    throw new TypeError('Argument must not be a number')
+  }
+  return Buffer(arg, encodingOrOffset, length)
+}
+
+SafeBuffer.alloc = function (size, fill, encoding) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  var buf = Buffer(size)
+  if (fill !== undefined) {
+    if (typeof encoding === 'string') {
+      buf.fill(fill, encoding)
+    } else {
+      buf.fill(fill)
+    }
+  } else {
+    buf.fill(0)
+  }
+  return buf
+}
+
+SafeBuffer.allocUnsafe = function (size) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  return Buffer(size)
+}
+
+SafeBuffer.allocUnsafeSlow = function (size) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  return buffer.SlowBuffer(size)
+}
diff --git a/server/node_modules/string_decoder/node_modules/safe-buffer/package.json b/server/node_modules/string_decoder/node_modules/safe-buffer/package.json
new file mode 100644
index 0000000..623fbc3
--- /dev/null
+++ b/server/node_modules/string_decoder/node_modules/safe-buffer/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "safe-buffer",
+  "description": "Safer Node.js Buffer API",
+  "version": "5.1.2",
+  "author": {
+    "name": "Feross Aboukhadijeh",
+    "email": "feross@feross.org",
+    "url": "http://feross.org"
+  },
+  "bugs": {
+    "url": "https://github.com/feross/safe-buffer/issues"
+  },
+  "devDependencies": {
+    "standard": "*",
+    "tape": "^4.0.0"
+  },
+  "homepage": "https://github.com/feross/safe-buffer",
+  "keywords": [
+    "buffer",
+    "buffer allocate",
+    "node security",
+    "safe",
+    "safe-buffer",
+    "security",
+    "uninitialized"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/feross/safe-buffer.git"
+  },
+  "scripts": {
+    "test": "standard && tape test/*.js"
+  }
+}
diff --git a/server/node_modules/string_decoder/package.json b/server/node_modules/string_decoder/package.json
new file mode 100644
index 0000000..518c3eb
--- /dev/null
+++ b/server/node_modules/string_decoder/package.json
@@ -0,0 +1,31 @@
+{
+  "name": "string_decoder",
+  "version": "1.1.1",
+  "description": "The string_decoder module from Node core",
+  "main": "lib/string_decoder.js",
+  "dependencies": {
+    "safe-buffer": "~5.1.0"
+  },
+  "devDependencies": {
+    "babel-polyfill": "^6.23.0",
+    "core-util-is": "^1.0.2",
+    "inherits": "^2.0.3",
+    "tap": "~0.4.8"
+  },
+  "scripts": {
+    "test": "tap test/parallel/*.js && node test/verify-dependencies",
+    "ci": "tap test/parallel/*.js test/ours/*.js --tap | tee test.tap && node test/verify-dependencies.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/nodejs/string_decoder.git"
+  },
+  "homepage": "https://github.com/nodejs/string_decoder",
+  "keywords": [
+    "string",
+    "decoder",
+    "browser",
+    "browserify"
+  ],
+  "license": "MIT"
+}
diff --git a/server/node_modules/strip-ansi/index.d.ts b/server/node_modules/strip-ansi/index.d.ts
new file mode 100644
index 0000000..907fccc
--- /dev/null
+++ b/server/node_modules/strip-ansi/index.d.ts
@@ -0,0 +1,17 @@
+/**
+Strip [ANSI escape codes](https://en.wikipedia.org/wiki/ANSI_escape_code) from a string.
+
+@example
+```
+import stripAnsi = require('strip-ansi');
+
+stripAnsi('\u001B[4mUnicorn\u001B[0m');
+//=> 'Unicorn'
+
+stripAnsi('\u001B]8;;https://github.com\u0007Click\u001B]8;;\u0007');
+//=> 'Click'
+```
+*/
+declare function stripAnsi(string: string): string;
+
+export = stripAnsi;
diff --git a/server/node_modules/strip-ansi/index.js b/server/node_modules/strip-ansi/index.js
new file mode 100644
index 0000000..9a593df
--- /dev/null
+++ b/server/node_modules/strip-ansi/index.js
@@ -0,0 +1,4 @@
+'use strict';
+const ansiRegex = require('ansi-regex');
+
+module.exports = string => typeof string === 'string' ? string.replace(ansiRegex(), '') : string;
diff --git a/server/node_modules/strip-ansi/license b/server/node_modules/strip-ansi/license
new file mode 100644
index 0000000..e7af2f7
--- /dev/null
+++ b/server/node_modules/strip-ansi/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/strip-ansi/package.json b/server/node_modules/strip-ansi/package.json
new file mode 100644
index 0000000..1a41108
--- /dev/null
+++ b/server/node_modules/strip-ansi/package.json
@@ -0,0 +1,54 @@
+{
+	"name": "strip-ansi",
+	"version": "6.0.1",
+	"description": "Strip ANSI escape codes from a string",
+	"license": "MIT",
+	"repository": "chalk/strip-ansi",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=8"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts"
+	],
+	"keywords": [
+		"strip",
+		"trim",
+		"remove",
+		"ansi",
+		"styles",
+		"color",
+		"colour",
+		"colors",
+		"terminal",
+		"console",
+		"string",
+		"tty",
+		"escape",
+		"formatting",
+		"rgb",
+		"256",
+		"shell",
+		"xterm",
+		"log",
+		"logging",
+		"command-line",
+		"text"
+	],
+	"dependencies": {
+		"ansi-regex": "^5.0.1"
+	},
+	"devDependencies": {
+		"ava": "^2.4.0",
+		"tsd": "^0.10.0",
+		"xo": "^0.25.3"
+	}
+}
diff --git a/server/node_modules/strip-ansi/readme.md b/server/node_modules/strip-ansi/readme.md
new file mode 100644
index 0000000..7c4b56d
--- /dev/null
+++ b/server/node_modules/strip-ansi/readme.md
@@ -0,0 +1,46 @@
+# strip-ansi [![Build Status](https://travis-ci.org/chalk/strip-ansi.svg?branch=master)](https://travis-ci.org/chalk/strip-ansi)
+
+> Strip [ANSI escape codes](https://en.wikipedia.org/wiki/ANSI_escape_code) from a string
+
+
+## Install
+
+```
+$ npm install strip-ansi
+```
+
+
+## Usage
+
+```js
+const stripAnsi = require('strip-ansi');
+
+stripAnsi('\u001B[4mUnicorn\u001B[0m');
+//=> 'Unicorn'
+
+stripAnsi('\u001B]8;;https://github.com\u0007Click\u001B]8;;\u0007');
+//=> 'Click'
+```
+
+
+## strip-ansi for enterprise
+
+Available as part of the Tidelift Subscription.
+
+The maintainers of strip-ansi and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. [Learn more.](https://tidelift.com/subscription/pkg/npm-strip-ansi?utm_source=npm-strip-ansi&utm_medium=referral&utm_campaign=enterprise&utm_term=repo)
+
+
+## Related
+
+- [strip-ansi-cli](https://github.com/chalk/strip-ansi-cli) - CLI for this module
+- [strip-ansi-stream](https://github.com/chalk/strip-ansi-stream) - Streaming version of this module
+- [has-ansi](https://github.com/chalk/has-ansi) - Check if a string has ANSI escape codes
+- [ansi-regex](https://github.com/chalk/ansi-regex) - Regular expression for matching ANSI escape codes
+- [chalk](https://github.com/chalk/chalk) - Terminal string styling done right
+
+
+## Maintainers
+
+- [Sindre Sorhus](https://github.com/sindresorhus)
+- [Josh Junon](https://github.com/qix-)
+
diff --git a/server/node_modules/strip-json-comments/index.js b/server/node_modules/strip-json-comments/index.js
new file mode 100644
index 0000000..4e6576e
--- /dev/null
+++ b/server/node_modules/strip-json-comments/index.js
@@ -0,0 +1,70 @@
+'use strict';
+var singleComment = 1;
+var multiComment = 2;
+
+function stripWithoutWhitespace() {
+	return '';
+}
+
+function stripWithWhitespace(str, start, end) {
+	return str.slice(start, end).replace(/\S/g, ' ');
+}
+
+module.exports = function (str, opts) {
+	opts = opts || {};
+
+	var currentChar;
+	var nextChar;
+	var insideString = false;
+	var insideComment = false;
+	var offset = 0;
+	var ret = '';
+	var strip = opts.whitespace === false ? stripWithoutWhitespace : stripWithWhitespace;
+
+	for (var i = 0; i < str.length; i++) {
+		currentChar = str[i];
+		nextChar = str[i + 1];
+
+		if (!insideComment && currentChar === '"') {
+			var escaped = str[i - 1] === '\\' && str[i - 2] !== '\\';
+			if (!escaped) {
+				insideString = !insideString;
+			}
+		}
+
+		if (insideString) {
+			continue;
+		}
+
+		if (!insideComment && currentChar + nextChar === '//') {
+			ret += str.slice(offset, i);
+			offset = i;
+			insideComment = singleComment;
+			i++;
+		} else if (insideComment === singleComment && currentChar + nextChar === '\r\n') {
+			i++;
+			insideComment = false;
+			ret += strip(str, offset, i);
+			offset = i;
+			continue;
+		} else if (insideComment === singleComment && currentChar === '\n') {
+			insideComment = false;
+			ret += strip(str, offset, i);
+			offset = i;
+		} else if (!insideComment && currentChar + nextChar === '/*') {
+			ret += str.slice(offset, i);
+			offset = i;
+			insideComment = multiComment;
+			i++;
+			continue;
+		} else if (insideComment === multiComment && currentChar + nextChar === '*/') {
+			i++;
+			insideComment = false;
+			ret += strip(str, offset, i + 1);
+			offset = i + 1;
+			continue;
+		}
+	}
+
+	return ret + (insideComment ? strip(str.substr(offset)) : str.substr(offset));
+};
diff --git a/server/node_modules/strip-json-comments/license b/server/node_modules/strip-json-comments/license
new file mode 100644
index 0000000..654d0bf
--- /dev/null
+++ b/server/node_modules/strip-json-comments/license
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/strip-json-comments/package.json b/server/node_modules/strip-json-comments/package.json
new file mode 100644
index 0000000..288ecc7
--- /dev/null
+++ b/server/node_modules/strip-json-comments/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "strip-json-comments",
+  "version": "2.0.1",
+  "description": "Strip comments from JSON. Lets you use comments in your JSON files!",
+  "license": "MIT",
+  "repository": "sindresorhus/strip-json-comments",
+  "author": {
+    "name": "Sindre Sorhus",
+    "email": "sindresorhus@gmail.com",
+    "url": "sindresorhus.com"
+  },
+  "engines": {
+    "node": ">=0.10.0"
+  },
+  "scripts": {
+    "test": "xo && ava"
+  },
+  "files": [
+    "index.js"
+  ],
+  "keywords": [
+    "json",
+    "strip",
+    "remove",
+    "delete",
+    "trim",
+    "comments",
+    "multiline",
+    "parse",
+    "config",
+    "configuration",
+    "conf",
+    "settings",
+    "util",
+    "env",
+    "environment"
+  ],
+  "devDependencies": {
+    "ava": "*",
+    "xo": "*"
+  }
+}
diff --git a/server/node_modules/strip-json-comments/readme.md b/server/node_modules/strip-json-comments/readme.md
new file mode 100644
index 0000000..0ee58df
--- /dev/null
+++ b/server/node_modules/strip-json-comments/readme.md
@@ -0,0 +1,64 @@
+# strip-json-comments [![Build Status](https://travis-ci.org/sindresorhus/strip-json-comments.svg?branch=master)](https://travis-ci.org/sindresorhus/strip-json-comments)
+
+> Strip comments from JSON. Lets you use comments in your JSON files!
+
+This is now possible:
+
+```js
+{
+	// rainbows
+	"unicorn": /* ❤ */ "cake"
+}
+```
+
+It will replace single-line comments `//` and multi-line comments `/**/` with whitespace. This allows JSON error positions to remain as close as possible to the original source.
+
+Also available as a [gulp](https://github.com/sindresorhus/gulp-strip-json-comments)/[grunt](https://github.com/sindresorhus/grunt-strip-json-comments)/[broccoli](https://github.com/sindresorhus/broccoli-strip-json-comments) plugin.
+
+
+## Install
+
+```
+$ npm install --save strip-json-comments
+```
+
+
+## Usage
+
+```js
+const json = '{/*rainbows*/"unicorn":"cake"}';
+
+JSON.parse(stripJsonComments(json));
+//=> {unicorn: 'cake'}
+```
+
+
+## API
+
+### stripJsonComments(input, [options])
+
+#### input
+
+Type: `string`
+
+Accepts a string with JSON and returns a string without comments.
+
+#### options
+
+##### whitespace
+
+Type: `boolean`  
+Default: `true`
+
+Replace comments with whitespace instead of stripping them entirely.
+
+
+## Related
+
+- [strip-json-comments-cli](https://github.com/sindresorhus/strip-json-comments-cli) - CLI for this module
+- [strip-css-comments](https://github.com/sindresorhus/strip-css-comments) - Strip comments from CSS
+
+
+## License
+
+MIT © [Sindre Sorhus](http://sindresorhus.com)
diff --git a/server/node_modules/tar-fs/.travis.yml b/server/node_modules/tar-fs/.travis.yml
new file mode 100644
index 0000000..977f7a6
--- /dev/null
+++ b/server/node_modules/tar-fs/.travis.yml
@@ -0,0 +1,6 @@
+language: node_js
+node_js:
+  - 8
+  - 10
+  - 12
+  - 14
diff --git a/server/node_modules/tar-fs/LICENSE b/server/node_modules/tar-fs/LICENSE
new file mode 100644
index 0000000..757562e
--- /dev/null
+++ b/server/node_modules/tar-fs/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Mathias Buus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/tar-fs/README.md b/server/node_modules/tar-fs/README.md
new file mode 100644
index 0000000..c6d35cf
--- /dev/null
+++ b/server/node_modules/tar-fs/README.md
@@ -0,0 +1,165 @@
+# tar-fs
+
+filesystem bindings for [tar-stream](https://github.com/mafintosh/tar-stream).
+
+```
+npm install tar-fs
+```
+
+[![build status](https://secure.travis-ci.org/mafintosh/tar-fs.png)](http://travis-ci.org/mafintosh/tar-fs)
+
+## Usage
+
+tar-fs allows you to pack directories into tarballs and extract tarballs into directories.
+
+It doesn't gunzip for you, so if you want to extract a `.tar.gz` with this you'll need to use something like [gunzip-maybe](https://github.com/mafintosh/gunzip-maybe) in addition to this.
+
+``` js
+var tar = require('tar-fs')
+var fs = require('fs')
+
+// packing a directory
+tar.pack('./my-directory').pipe(fs.createWriteStream('my-tarball.tar'))
+
+// extracting a directory
+fs.createReadStream('my-other-tarball.tar').pipe(tar.extract('./my-other-directory'))
+```
+
+To ignore various files when packing or extracting add a ignore function to the options. `ignore`
+is also an alias for `filter`. Additionally you get `header` if you use ignore while extracting.
+That way you could also filter by metadata.
+
+``` js
+var pack = tar.pack('./my-directory', {
+  ignore: function(name) {
+    return path.extname(name) === '.bin' // ignore .bin files when packing
+  }
+})
+
+var extract = tar.extract('./my-other-directory', {
+  ignore: function(name) {
+    return path.extname(name) === '.bin' // ignore .bin files inside the tarball when extracing
+  }
+})
+
+var extractFilesDirs = tar.extract('./my-other-other-directory', {
+  ignore: function(_, header) {
+    // pass files & directories, ignore e.g. symlinks
+    return header.type !== 'file' && header.type !== 'directory'
+  }
+})
+```
+
+You can also specify which entries to pack using the `entries` option
+
+```js
+var pack = tar.pack('./my-directory', {
+  entries: ['file1', 'subdir/file2'] // only the specific entries will be packed
+})
+```
+
+If you want to modify the headers when packing/extracting add a map function to the options
+
+``` js
+var pack = tar.pack('./my-directory', {
+  map: function(header) {
+    header.name = 'prefixed/'+header.name
+    return header
+  }
+})
+
+var extract = tar.extract('./my-directory', {
+  map: function(header) {
+    header.name = 'another-prefix/'+header.name
+    return header
+  }
+})
+```
+
+Similarly you can use `mapStream` incase you wanna modify the input/output file streams
+
+``` js
+var pack = tar.pack('./my-directory', {
+  mapStream: function(fileStream, header) {
+    // NOTE: the returned stream HAS to have the same length as the input stream.
+    // If not make sure to update the size in the header passed in here.
+    if (path.extname(header.name) === '.js') {
+      return fileStream.pipe(someTransform)
+    }
+    return fileStream;
+  }
+})
+
+var extract = tar.extract('./my-directory', {
+  mapStream: function(fileStream, header) {
+    if (path.extname(header.name) === '.js') {
+      return fileStream.pipe(someTransform)
+    }
+    return fileStream;
+  }
+})
+```
+
+Set `options.fmode` and `options.dmode` to ensure that files/directories extracted have the corresponding modes
+
+``` js
+var extract = tar.extract('./my-directory', {
+  dmode: parseInt(555, 8), // all dirs should be readable
+  fmode: parseInt(444, 8) // all files should be readable
+})
+```
+
+It can be useful to use `dmode` and `fmode` if you are packing/unpacking tarballs between *nix/windows to ensure that all files/directories unpacked are readable.
+
+Alternatively you can set `options.readable` and/or `options.writable` to set the dmode and fmode to readable/writable.
+
+``` js
+var extract = tar.extract('./my-directory', {
+  readable: true, // all dirs and files should be readable
+  writable: true, // all dirs and files should be writable
+})
+```
+
+Set `options.strict` to `false` if you want to ignore errors due to unsupported entry types (like device files)
+
+To dereference symlinks (pack the contents of the symlink instead of the link itself) set `options.dereference` to `true`.
+
+## Copy a directory
+
+Copying a directory with permissions and mtime intact is as simple as
+
+``` js
+tar.pack('source-directory').pipe(tar.extract('dest-directory'))
+```
+
+## Interaction with [`tar-stream`](https://github.com/mafintosh/tar-stream)
+
+Use `finalize: false` and the `finish` hook to
+leave the pack stream open for further entries (see
+[`tar-stream#pack`](https://github.com/mafintosh/tar-stream#packing)),
+and use `pack` to pass an existing pack stream.
+
+``` js
+var mypack = tar.pack('./my-directory', {
+  finalize: false,
+  finish: function(sameAsMypack) {
+    mypack.entry({name: 'generated-file.txt'}, "hello")
+    tar.pack('./other-directory', {
+      pack: sameAsMypack
+    })
+  }
+})
+```
+
+
+## Performance
+
+Packing and extracting a 6.1 GB with 2496 directories and 2398 files yields the following results on my Macbook Air.
+[See the benchmark here](https://gist.github.com/mafintosh/8102201)
+
+* tar-fs: 34.261 seconds
+* [node-tar](https://github.com/isaacs/node-tar): 366.123 seconds (or 10x slower)
+
+## License
+
+MIT
diff --git a/server/node_modules/tar-fs/index.js b/server/node_modules/tar-fs/index.js
new file mode 100644
index 0000000..4797bc9
--- /dev/null
+++ b/server/node_modules/tar-fs/index.js
@@ -0,0 +1,363 @@
+var chownr = require('chownr')
+var tar = require('tar-stream')
+var pump = require('pump')
+var mkdirp = require('mkdirp-classic')
+var fs = require('fs')
+var path = require('path')
+var os = require('os')
+
+var win32 = os.platform() === 'win32'
+
+var noop = function () {}
+
+var echo = function (name) {
+  return name
+}
+
+var normalize = !win32 ? echo : function (name) {
+  return name.replace(/\\/g, '/').replace(/[:?<>|]/g, '_')
+}
+
+var statAll = function (fs, stat, cwd, ignore, entries, sort) {
+  var queue = entries || ['.']
+
+  return function loop (callback) {
+    if (!queue.length) return callback()
+    var next = queue.shift()
+    var nextAbs = path.join(cwd, next)
+
+    stat.call(fs, nextAbs, function (err, stat) {
+      if (err) return callback(err)
+
+      if (!stat.isDirectory()) return callback(null, next, stat)
+
+      fs.readdir(nextAbs, function (err, files) {
+        if (err) return callback(err)
+
+        if (sort) files.sort()
+        for (var i = 0; i < files.length; i++) {
+          if (!ignore(path.join(cwd, next, files[i]))) queue.push(path.join(next, files[i]))
+        }
+
+        callback(null, next, stat)
+      })
+    })
+  }
+}
+
+var strip = function (map, level) {
+  return function (header) {
+    header.name = header.name.split('/').slice(level).join('/')
+
+    var linkname = header.linkname
+    if (linkname && (header.type === 'link' || path.isAbsolute(linkname))) {
+      header.linkname = linkname.split('/').slice(level).join('/')
+    }
+
+    return map(header)
+  }
+}
+
+exports.pack = function (cwd, opts) {
+  if (!cwd) cwd = '.'
+  if (!opts) opts = {}
+
+  var xfs = opts.fs || fs
+  var ignore = opts.ignore || opts.filter || noop
+  var map = opts.map || noop
+  var mapStream = opts.mapStream || echo
+  var statNext = statAll(xfs, opts.dereference ? xfs.stat : xfs.lstat, cwd, ignore, opts.entries, opts.sort)
+  var strict = opts.strict !== false
+  var umask = typeof opts.umask === 'number' ? ~opts.umask : ~processUmask()
+  var dmode = typeof opts.dmode === 'number' ? opts.dmode : 0
+  var fmode = typeof opts.fmode === 'number' ? opts.fmode : 0
+  var pack = opts.pack || tar.pack()
+  var finish = opts.finish || noop
+
+  if (opts.strip) map = strip(map, opts.strip)
+
+  if (opts.readable) {
+    dmode |= parseInt(555, 8)
+    fmode |= parseInt(444, 8)
+  }
+  if (opts.writable) {
+    dmode |= parseInt(333, 8)
+    fmode |= parseInt(222, 8)
+  }
+
+  var onsymlink = function (filename, header) {
+    xfs.readlink(path.join(cwd, filename), function (err, linkname) {
+      if (err) return pack.destroy(err)
+      header.linkname = normalize(linkname)
+      pack.entry(header, onnextentry)
+    })
+  }
+
+  var onstat = function (err, filename, stat) {
+    if (err) return pack.destroy(err)
+    if (!filename) {
+      if (opts.finalize !== false) pack.finalize()
+      return finish(pack)
+    }
+
+    if (stat.isSocket()) return onnextentry() // tar does not support sockets...
+
+    var header = {
+      name: normalize(filename),
+      mode: (stat.mode | (stat.isDirectory() ? dmode : fmode)) & umask,
+      mtime: stat.mtime,
+      size: stat.size,
+      type: 'file',
+      uid: stat.uid,
+      gid: stat.gid
+    }
+
+    if (stat.isDirectory()) {
+      header.size = 0
+      header.type = 'directory'
+      header = map(header) || header
+      return pack.entry(header, onnextentry)
+    }
+
+    if (stat.isSymbolicLink()) {
+      header.size = 0
+      header.type = 'symlink'
+      header = map(header) || header
+      return onsymlink(filename, header)
+    }
+
+    // TODO: add fifo etc...
+
+    header = map(header) || header
+
+    if (!stat.isFile()) {
+      if (strict) return pack.destroy(new Error('unsupported type for ' + filename))
+      return onnextentry()
+    }
+
+    var entry = pack.entry(header, onnextentry)
+    if (!entry) return
+
+    var rs = mapStream(xfs.createReadStream(path.join(cwd, filename), { start: 0, end: header.size > 0 ? header.size - 1 : header.size }), header)
+
+    rs.on('error', function (err) { // always forward errors on destroy
+      entry.destroy(err)
+    })
+
+    pump(rs, entry)
+  }
+
+  var onnextentry = function (err) {
+    if (err) return pack.destroy(err)
+    statNext(onstat)
+  }
+
+  onnextentry()
+
+  return pack
+}
+
+var head = function (list) {
+  return list.length ? list[list.length - 1] : null
+}
+
+var processGetuid = function () {
+  return process.getuid ? process.getuid() : -1
+}
+
+var processUmask = function () {
+  return process.umask ? process.umask() : 0
+}
+
+exports.extract = function (cwd, opts) {
+  if (!cwd) cwd = '.'
+  if (!opts) opts = {}
+
+  var xfs = opts.fs || fs
+  var ignore = opts.ignore || opts.filter || noop
+  var map = opts.map || noop
+  var mapStream = opts.mapStream || echo
+  var own = opts.chown !== false && !win32 && processGetuid() === 0
+  var extract = opts.extract || tar.extract()
+  var stack = []
+  var now = new Date()
+  var umask = typeof opts.umask === 'number' ? ~opts.umask : ~processUmask()
+  var dmode = typeof opts.dmode === 'number' ? opts.dmode : 0
+  var fmode = typeof opts.fmode === 'number' ? opts.fmode : 0
+  var strict = opts.strict !== false
+
+  if (opts.strip) map = strip(map, opts.strip)
+
+  if (opts.readable) {
+    dmode |= parseInt(555, 8)
+    fmode |= parseInt(444, 8)
+  }
+  if (opts.writable) {
+    dmode |= parseInt(333, 8)
+    fmode |= parseInt(222, 8)
+  }
+
+  var utimesParent = function (name, cb) { // we just set the mtime on the parent dir again everytime we write an entry
+    var top
+    while ((top = head(stack)) && name.slice(0, top[0].length) !== top[0]) stack.pop()
+    if (!top) return cb()
+    xfs.utimes(top[0], now, top[1], cb)
+  }
+
+  var utimes = function (name, header, cb) {
+    if (opts.utimes === false) return cb()
+
+    if (header.type === 'directory') return xfs.utimes(name, now, header.mtime, cb)
+    if (header.type === 'symlink') return utimesParent(name, cb) // TODO: how to set mtime on link?
+
+    xfs.utimes(name, now, header.mtime, function (err) {
+      if (err) return cb(err)
+      utimesParent(name, cb)
+    })
+  }
+
+  var chperm = function (name, header, cb) {
+    var link = header.type === 'symlink'
+
+    /* eslint-disable node/no-deprecated-api */
+    var chmod = link ? xfs.lchmod : xfs.chmod
+    var chown = link ? xfs.lchown : xfs.chown
+    /* eslint-enable node/no-deprecated-api */
+
+    if (!chmod) return cb()
+
+    var mode = (header.mode | (header.type === 'directory' ? dmode : fmode)) & umask
+
+    if (chown && own) chown.call(xfs, name, header.uid, header.gid, onchown)
+    else onchown(null)
+
+    function onchown (err) {
+      if (err) return cb(err)
+      if (!chmod) return cb()
+      chmod.call(xfs, name, mode, cb)
+    }
+  }
+
+  extract.on('entry', function (header, stream, next) {
+    header = map(header) || header
+    header.name = normalize(header.name)
+    var name = path.join(cwd, path.join('/', header.name))
+
+    if (ignore(name, header)) {
+      stream.resume()
+      return next()
+    }
+
+    var stat = function (err) {
+      if (err) return next(err)
+      utimes(name, header, function (err) {
+        if (err) return next(err)
+        if (win32) return next()
+        chperm(name, header, next)
+      })
+    }
+
+    var onsymlink = function () {
+      if (win32) return next() // skip symlinks on win for now before it can be tested
+      xfs.unlink(name, function () {
+        var dst = path.resolve(path.dirname(name), header.linkname)
+        if (!inCwd(dst, cwd)) return next(new Error(name + ' is not a valid symlink'))
+
+        xfs.symlink(header.linkname, name, stat)
+      })
+    }
+
+    var onlink = function () {
+      if (win32) return next() // skip links on win for now before it can be tested
+      xfs.unlink(name, function () {
+        var srcpath = path.join(cwd, path.join('/', header.linkname))
+
+        xfs.realpath(srcpath, function (err, dst) {
+          if (err || !inCwd(dst, cwd)) return next(new Error(name + ' is not a valid hardlink'))
+
+          xfs.link(dst, name, function (err) {
+            if (err && err.code === 'EPERM' && opts.hardlinkAsFilesFallback) {
+              stream = xfs.createReadStream(srcpath)
+              return onfile()
+            }
+
+            stat(err)
+          })
+        })
+      })
+    }
+
+    var onfile = function () {
+      var ws = xfs.createWriteStream(name)
+      var rs = mapStream(stream, header)
+
+      ws.on('error', function (err) { // always forward errors on destroy
+        rs.destroy(err)
+      })
+
+      pump(rs, ws, function (err) {
+        if (err) return next(err)
+        ws.on('close', stat)
+      })
+    }
+
+    if (header.type === 'directory') {
+      stack.push([name, header.mtime])
+      return mkdirfix(name, {
+        fs: xfs, own: own, uid: header.uid, gid: header.gid
+      }, stat)
+    }
+
+    var dir = path.dirname(name)
+
+    validate(xfs, dir, path.join(cwd, '.'), function (err, valid) {
+      if (err) return next(err)
+      if (!valid) return next(new Error(dir + ' is not a valid path'))
+
+      mkdirfix(dir, {
+        fs: xfs, own: own, uid: header.uid, gid: header.gid
+      }, function (err) {
+        if (err) return next(err)
+
+        switch (header.type) {
+          case 'file': return onfile()
+          case 'link': return onlink()
+          case 'symlink': return onsymlink()
+        }
+
+        if (strict) return next(new Error('unsupported type for ' + name + ' (' + header.type + ')'))
+
+        stream.resume()
+        next()
+      })
+    })
+  })
+
+  if (opts.finish) extract.on('finish', opts.finish)
+
+  return extract
+}
+
+function validate (fs, name, root, cb) {
+  if (name === root) return cb(null, true)
+  fs.lstat(name, function (err, st) {
+    if (err && err.code !== 'ENOENT') return cb(err)
+    if (err || st.isDirectory()) return validate(fs, path.join(name, '..'), root, cb)
+    cb(null, false)
+  })
+}
+
+function mkdirfix (name, opts, cb) {
+  mkdirp(name, { fs: opts.fs }, function (err, made) {
+    if (!err && made && opts.own) {
+      chownr(made, opts.uid, opts.gid, cb)
+    } else {
+      cb(err)
+    }
+  })
+}
+
+function inCwd (dst, cwd) {
+  cwd = path.resolve(cwd)
+  return cwd === dst || dst.startsWith(cwd + path.sep)
+}
diff --git a/server/node_modules/tar-fs/package.json b/server/node_modules/tar-fs/package.json
new file mode 100644
index 0000000..6136577
--- /dev/null
+++ b/server/node_modules/tar-fs/package.json
@@ -0,0 +1,41 @@
+{
+  "name": "tar-fs",
+  "version": "2.1.4",
+  "description": "filesystem bindings for tar-stream",
+  "dependencies": {
+    "chownr": "^1.1.1",
+    "mkdirp-classic": "^0.5.2",
+    "pump": "^3.0.0",
+    "tar-stream": "^2.1.4"
+  },
+  "keywords": [
+    "tar",
+    "fs",
+    "file",
+    "tarball",
+    "directory",
+    "stream"
+  ],
+  "devDependencies": {
+    "rimraf": "^2.6.3",
+    "standard": "^13.0.1",
+    "tape": "^4.9.2"
+  },
+  "scripts": {
+    "test": "standard && tape test/index.js"
+  },
+  "bugs": {
+    "url": "https://github.com/mafintosh/tar-fs/issues"
+  },
+  "homepage": "https://github.com/mafintosh/tar-fs",
+  "main": "index.js",
+  "directories": {
+    "test": "test"
+  },
+  "author": "Mathias Buus",
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/mafintosh/tar-fs.git"
+  }
+}
diff --git a/server/node_modules/tar-fs/test/fixtures/a/hello.txt b/server/node_modules/tar-fs/test/fixtures/a/hello.txt
new file mode 100644
index 0000000..3b18e51
--- /dev/null
+++ b/server/node_modules/tar-fs/test/fixtures/a/hello.txt
@@ -0,0 +1 @@
+hello world
diff --git a/server/node_modules/tar-fs/test/fixtures/b/a/test.txt b/server/node_modules/tar-fs/test/fixtures/b/a/test.txt
new file mode 100644
index 0000000..9daeafb
--- /dev/null
+++ b/server/node_modules/tar-fs/test/fixtures/b/a/test.txt
@@ -0,0 +1 @@
+test
diff --git a/server/node_modules/tar-fs/test/fixtures/d/file1 b/server/node_modules/tar-fs/test/fixtures/d/file1
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/tar-fs/test/fixtures/d/file2 b/server/node_modules/tar-fs/test/fixtures/d/file2
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/tar-fs/test/fixtures/d/sub-dir/file5 b/server/node_modules/tar-fs/test/fixtures/d/sub-dir/file5
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/tar-fs/test/fixtures/d/sub-files/file3 b/server/node_modules/tar-fs/test/fixtures/d/sub-files/file3
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/tar-fs/test/fixtures/d/sub-files/file4 b/server/node_modules/tar-fs/test/fixtures/d/sub-files/file4
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/tar-fs/test/fixtures/e/directory/.ignore b/server/node_modules/tar-fs/test/fixtures/e/directory/.ignore
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/tar-fs/test/fixtures/e/file b/server/node_modules/tar-fs/test/fixtures/e/file
new file mode 100644
index 0000000..e69de29
diff --git a/server/node_modules/tar-fs/test/fixtures/invalid.tar b/server/node_modules/tar-fs/test/fixtures/invalid.tar
new file mode 100644
index 0000000..a645e9c
Binary files /dev/null and b/server/node_modules/tar-fs/test/fixtures/invalid.tar differ
diff --git a/server/node_modules/tar-fs/test/index.js b/server/node_modules/tar-fs/test/index.js
new file mode 100644
index 0000000..f983b4c
--- /dev/null
+++ b/server/node_modules/tar-fs/test/index.js
@@ -0,0 +1,346 @@
+var test = require('tape')
+var rimraf = require('rimraf')
+var tar = require('../index')
+var tarStream = require('tar-stream')
+var path = require('path')
+var fs = require('fs')
+var os = require('os')
+
+var win32 = os.platform() === 'win32'
+
+var mtime = function (st) {
+  return Math.floor(st.mtime.getTime() / 1000)
+}
+
+test('copy a -> copy/a', function (t) {
+  t.plan(5)
+
+  var a = path.join(__dirname, 'fixtures', 'a')
+  var b = path.join(__dirname, 'fixtures', 'copy', 'a')
+
+  rimraf.sync(b)
+  tar.pack(a)
+    .pipe(tar.extract(b))
+    .on('finish', function () {
+      var files = fs.readdirSync(b)
+      t.same(files.length, 1)
+      t.same(files[0], 'hello.txt')
+      var fileB = path.join(b, files[0])
+      var fileA = path.join(a, files[0])
+      t.same(fs.readFileSync(fileB, 'utf-8'), fs.readFileSync(fileA, 'utf-8'))
+      t.same(fs.statSync(fileB).mode, fs.statSync(fileA).mode)
+      t.same(mtime(fs.statSync(fileB)), mtime(fs.statSync(fileA)))
+    })
+})
+
+test('copy b -> copy/b', function (t) {
+  t.plan(8)
+
+  var a = path.join(__dirname, 'fixtures', 'b')
+  var b = path.join(__dirname, 'fixtures', 'copy', 'b')
+
+  rimraf.sync(b)
+  tar.pack(a)
+    .pipe(tar.extract(b))
+    .on('finish', function () {
+      var files = fs.readdirSync(b)
+      t.same(files.length, 1)
+      t.same(files[0], 'a')
+      var dirB = path.join(b, files[0])
+      var dirA = path.join(a, files[0])
+      t.same(fs.statSync(dirB).mode, fs.statSync(dirA).mode)
+      t.same(mtime(fs.statSync(dirB)), mtime(fs.statSync(dirA)))
+      t.ok(fs.statSync(dirB).isDirectory())
+      var fileB = path.join(dirB, 'test.txt')
+      var fileA = path.join(dirA, 'test.txt')
+      t.same(fs.readFileSync(fileB, 'utf-8'), fs.readFileSync(fileA, 'utf-8'))
+      t.same(fs.statSync(fileB).mode, fs.statSync(fileA).mode)
+      t.same(mtime(fs.statSync(fileB)), mtime(fs.statSync(fileA)))
+    })
+})
+
+test('symlink', function (t) {
+  if (win32) { // no symlink support on win32 currently. TODO: test if this can be enabled somehow
+    t.plan(1)
+    t.ok(true)
+    return
+  }
+
+  t.plan(5)
+
+  var a = path.join(__dirname, 'fixtures', 'c')
+
+  rimraf.sync(path.join(a, 'link'))
+  fs.symlinkSync('.gitignore', path.join(a, 'link'))
+
+  var b = path.join(__dirname, 'fixtures', 'copy', 'c')
+
+  rimraf.sync(b)
+  tar.pack(a)
+    .pipe(tar.extract(b))
+    .on('finish', function () {
+      var files = fs.readdirSync(b).sort()
+      t.same(files.length, 2)
+      t.same(files[0], '.gitignore')
+      t.same(files[1], 'link')
+
+      var linkA = path.join(a, 'link')
+      var linkB = path.join(b, 'link')
+
+      t.same(mtime(fs.lstatSync(linkB)), mtime(fs.lstatSync(linkA)))
+      t.same(fs.readlinkSync(linkB), fs.readlinkSync(linkA))
+    })
+})
+
+test('follow symlinks', function (t) {
+  if (win32) { // no symlink support on win32 currently. TODO: test if this can be enabled somehow
+    t.plan(1)
+    t.ok(true)
+    return
+  }
+
+  t.plan(5)
+
+  var a = path.join(__dirname, 'fixtures', 'c')
+
+  rimraf.sync(path.join(a, 'link'))
+  fs.symlinkSync('.gitignore', path.join(a, 'link'))
+
+  var b = path.join(__dirname, 'fixtures', 'copy', 'c-dereference')
+
+  rimraf.sync(b)
+  tar.pack(a, { dereference: true })
+    .pipe(tar.extract(b))
+    .on('finish', function () {
+      var files = fs.readdirSync(b).sort()
+      t.same(files.length, 2)
+      t.same(files[0], '.gitignore')
+      t.same(files[1], 'link')
+
+      var file1 = path.join(b, '.gitignore')
+      var file2 = path.join(b, 'link')
+
+      t.same(mtime(fs.lstatSync(file1)), mtime(fs.lstatSync(file2)))
+      t.same(fs.readFileSync(file1), fs.readFileSync(file2))
+    })
+})
+
+test('strip', function (t) {
+  t.plan(2)
+
+  var a = path.join(__dirname, 'fixtures', 'b')
+  var b = path.join(__dirname, 'fixtures', 'copy', 'b-strip')
+
+  rimraf.sync(b)
+
+  tar.pack(a)
+    .pipe(tar.extract(b, { strip: 1 }))
+    .on('finish', function () {
+      var files = fs.readdirSync(b).sort()
+      t.same(files.length, 1)
+      t.same(files[0], 'test.txt')
+    })
+})
+
+test('strip + map', function (t) {
+  t.plan(2)
+
+  var a = path.join(__dirname, 'fixtures', 'b')
+  var b = path.join(__dirname, 'fixtures', 'copy', 'b-strip')
+
+  rimraf.sync(b)
+
+  var uppercase = function (header) {
+    header.name = header.name.toUpperCase()
+    return header
+  }
+
+  tar.pack(a)
+    .pipe(tar.extract(b, { strip: 1, map: uppercase }))
+    .on('finish', function () {
+      var files = fs.readdirSync(b).sort()
+      t.same(files.length, 1)
+      t.same(files[0], 'TEST.TXT')
+    })
+})
+
+test('map + dir + permissions', function (t) {
+  t.plan(win32 ? 1 : 2) // skip chmod test, it's not working like unix
+
+  var a = path.join(__dirname, 'fixtures', 'b')
+  var b = path.join(__dirname, 'fixtures', 'copy', 'a-perms')
+
+  rimraf.sync(b)
+
+  var aWithMode = function (header) {
+    if (header.name === 'a') {
+      header.mode = parseInt(700, 8)
+    }
+    return header
+  }
+
+  tar.pack(a)
+    .pipe(tar.extract(b, { map: aWithMode }))
+    .on('finish', function () {
+      var files = fs.readdirSync(b).sort()
+      var stat = fs.statSync(path.join(b, 'a'))
+      t.same(files.length, 1)
+      if (!win32) {
+        t.same(stat.mode & parseInt(777, 8), parseInt(700, 8))
+      }
+    })
+})
+
+test('specific entries', function (t) {
+  t.plan(6)
+
+  var a = path.join(__dirname, 'fixtures', 'd')
+  var b = path.join(__dirname, 'fixtures', 'copy', 'd-entries')
+
+  var entries = ['file1', 'sub-files/file3', 'sub-dir']
+
+  rimraf.sync(b)
+  tar.pack(a, { entries: entries })
+    .pipe(tar.extract(b))
+    .on('finish', function () {
+      var files = fs.readdirSync(b)
+      t.same(files.length, 3)
+      t.notSame(files.indexOf('file1'), -1)
+      t.notSame(files.indexOf('sub-files'), -1)
+      t.notSame(files.indexOf('sub-dir'), -1)
+      var subFiles = fs.readdirSync(path.join(b, 'sub-files'))
+      t.same(subFiles, ['file3'])
+      var subDir = fs.readdirSync(path.join(b, 'sub-dir'))
+      t.same(subDir, ['file5'])
+    })
+})
+
+test('check type while mapping header on packing', function (t) {
+  t.plan(3)
+
+  var e = path.join(__dirname, 'fixtures', 'e')
+
+  var checkHeaderType = function (header) {
+    if (header.name.indexOf('.') === -1) t.same(header.type, header.name)
+  }
+
+  tar.pack(e, { map: checkHeaderType })
+})
+
+test('finish callbacks', function (t) {
+  t.plan(3)
+
+  var a = path.join(__dirname, 'fixtures', 'a')
+  var b = path.join(__dirname, 'fixtures', 'copy', 'a')
+
+  rimraf.sync(b)
+
+  var packEntries = 0
+  var extractEntries = 0
+
+  var countPackEntry = function (header) { packEntries++ }
+  var countExtractEntry = function (header) { extractEntries++ }
+
+  var pack
+  var onPackFinish = function (passedPack) {
+    t.equal(packEntries, 2, 'All entries have been packed') // 2 entries - the file and base directory
+    t.equal(passedPack, pack, 'The finish hook passes the pack')
+  }
+
+  var onExtractFinish = function () { t.equal(extractEntries, 2) }
+
+  pack = tar.pack(a, { map: countPackEntry, finish: onPackFinish })
+
+  pack.pipe(tar.extract(b, { map: countExtractEntry, finish: onExtractFinish }))
+    .on('finish', function () {
+      t.end()
+    })
+})
+
+test('not finalizing the pack', function (t) {
+  t.plan(2)
+
+  var a = path.join(__dirname, 'fixtures', 'a')
+  var b = path.join(__dirname, 'fixtures', 'b')
+
+  var out = path.join(__dirname, 'fixtures', 'copy', 'merged-packs')
+
+  rimraf.sync(out)
+
+  var prefixer = function (prefix) {
+    return function (header) {
+      header.name = path.join(prefix, header.name)
+      return header
+    }
+  }
+
+  tar.pack(a, {
+    map: prefixer('a-files'),
+    finalize: false,
+    finish: packB
+  })
+
+  function packB (pack) {
+    tar.pack(b, { pack: pack, map: prefixer('b-files') })
+      .pipe(tar.extract(out))
+      .on('finish', assertResults)
+  }
+
+  function assertResults () {
+    var containers = fs.readdirSync(out)
+    t.deepEqual(containers, ['a-files', 'b-files'])
+    var aFiles = fs.readdirSync(path.join(out, 'a-files'))
+    t.deepEqual(aFiles, ['hello.txt'])
+  }
+})
+
+test('do not extract invalid tar', function (t) {
+  var a = path.join(__dirname, 'fixtures', 'invalid.tar')
+
+  var out = path.join(__dirname, 'fixtures', 'invalid')
+
+  rimraf.sync(out)
+
+  fs.createReadStream(a)
+    .pipe(tar.extract(out))
+    .on('error', function (err) {
+      t.ok(/is not a valid symlink/i.test(err.message))
+      fs.stat(path.join(out, '../bar'), function (err) {
+        t.ok(err)
+        t.end()
+      })
+    })
+})
+
+test('no abs hardlink targets', function (t) {
+  var out = path.join(__dirname, 'fixtures', 'invalid')
+  var outside = path.join(__dirname, 'fixtures', 'outside')
+
+  rimraf.sync(out)
+
+  var s = tarStream.pack()
+
+  fs.writeFileSync(outside, 'something')
+
+  s.entry({
+    type: 'link',
+    name: 'link',
+    linkname: outside
+  })
+
+  s.entry({
+    name: 'link'
+  }, 'overwrite')
+
+  s.finalize()
+
+  s.pipe(tar.extract(out))
+    .on('error', function (err) {
+      t.ok(err, 'had error')
+      fs.readFile(outside, 'utf-8', function (err, str) {
+        t.error(err, 'no error')
+        t.same(str, 'something')
+        t.end()
+      })
+    })
+})
diff --git a/server/node_modules/tar-stream/LICENSE b/server/node_modules/tar-stream/LICENSE
new file mode 100644
index 0000000..757562e
--- /dev/null
+++ b/server/node_modules/tar-stream/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Mathias Buus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/README.md b/server/node_modules/tar-stream/README.md
new file mode 100644
index 0000000..2679d9d
--- /dev/null
+++ b/server/node_modules/tar-stream/README.md
@@ -0,0 +1,168 @@
+# tar-stream
+
+tar-stream is a streaming tar parser and generator and nothing else. It is streams2 and operates purely using streams which means you can easily extract/parse tarballs without ever hitting the file system.
+
+Note that you still need to gunzip your data if you have a `.tar.gz`. We recommend using [gunzip-maybe](https://github.com/mafintosh/gunzip-maybe) in conjunction with this.
+
+```
+npm install tar-stream
+```
+
+[![build status](https://secure.travis-ci.org/mafintosh/tar-stream.png)](http://travis-ci.org/mafintosh/tar-stream)
+[![License](https://img.shields.io/badge/license-MIT-blue.svg)](http://opensource.org/licenses/MIT)
+
+## Usage
+
+tar-stream exposes two streams, [pack](https://github.com/mafintosh/tar-stream#packing) which creates tarballs and [extract](https://github.com/mafintosh/tar-stream#extracting) which extracts tarballs. To [modify an existing tarball](https://github.com/mafintosh/tar-stream#modifying-existing-tarballs) use both.
+
+
+It implementes USTAR with additional support for pax extended headers. It should be compatible with all popular tar distributions out there (gnutar, bsdtar etc)
+
+## Related
+
+If you want to pack/unpack directories on the file system check out [tar-fs](https://github.com/mafintosh/tar-fs) which provides file system bindings to this module.
+
+## Packing
+
+To create a pack stream use `tar.pack()` and call `pack.entry(header, [callback])` to add tar entries.
+
+``` js
+var tar = require('tar-stream')
+var pack = tar.pack() // pack is a streams2 stream
+
+// add a file called my-test.txt with the content "Hello World!"
+pack.entry({ name: 'my-test.txt' }, 'Hello World!')
+
+// add a file called my-stream-test.txt from a stream
+var entry = pack.entry({ name: 'my-stream-test.txt', size: 11 }, function(err) {
+  // the stream was added
+  // no more entries
+  pack.finalize()
+})
+
+entry.write('hello')
+entry.write(' ')
+entry.write('world')
+entry.end()
+
+// pipe the pack stream somewhere
+pack.pipe(process.stdout)
+```
+
+## Extracting
+
+To extract a stream use `tar.extract()` and listen for `extract.on('entry', (header, stream, next) )`
+
+``` js
+var extract = tar.extract()
+
+extract.on('entry', function(header, stream, next) {
+  // header is the tar header
+  // stream is the content body (might be an empty stream)
+  // call next when you are done with this entry
+
+  stream.on('end', function() {
+    next() // ready for next entry
+  })
+
+  stream.resume() // just auto drain the stream
+})
+
+extract.on('finish', function() {
+  // all entries read
+})
+
+pack.pipe(extract)
+```
+
+The tar archive is streamed sequentially, meaning you **must** drain each entry's stream as you get them or else the main extract stream will receive backpressure and stop reading.
+
+## Headers
+
+The header object using in `entry` should contain the following properties.
+Most of these values can be found by stat'ing a file.
+
+``` js
+{
+  name: 'path/to/this/entry.txt',
+  size: 1314,        // entry size. defaults to 0
+  mode: 0o644,       // entry mode. defaults to to 0o755 for dirs and 0o644 otherwise
+  mtime: new Date(), // last modified date for entry. defaults to now.
+  type: 'file',      // type of entry. defaults to file. can be:
+                     // file | link | symlink | directory | block-device
+                     // character-device | fifo | contiguous-file
+  linkname: 'path',  // linked file name
+  uid: 0,            // uid of entry owner. defaults to 0
+  gid: 0,            // gid of entry owner. defaults to 0
+  uname: 'maf',      // uname of entry owner. defaults to null
+  gname: 'staff',    // gname of entry owner. defaults to null
+  devmajor: 0,       // device major version. defaults to 0
+  devminor: 0        // device minor version. defaults to 0
+}
+```
+
+## Modifying existing tarballs
+
+Using tar-stream it is easy to rewrite paths / change modes etc in an existing tarball.
+
+``` js
+var extract = tar.extract()
+var pack = tar.pack()
+var path = require('path')
+
+extract.on('entry', function(header, stream, callback) {
+  // let's prefix all names with 'tmp'
+  header.name = path.join('tmp', header.name)
+  // write the new entry to the pack stream
+  stream.pipe(pack.entry(header, callback))
+})
+
+extract.on('finish', function() {
+  // all entries done - lets finalize it
+  pack.finalize()
+})
+
+// pipe the old tarball to the extractor
+oldTarballStream.pipe(extract)
+
+// pipe the new tarball the another stream
+pack.pipe(newTarballStream)
+```
+
+## Saving tarball to fs
+
+
+``` js
+var fs = require('fs')
+var tar = require('tar-stream')
+
+var pack = tar.pack() // pack is a streams2 stream
+var path = 'YourTarBall.tar'
+var yourTarball = fs.createWriteStream(path)
+
+// add a file called YourFile.txt with the content "Hello World!"
+pack.entry({name: 'YourFile.txt'}, 'Hello World!', function (err) {
+  if (err) throw err
+  pack.finalize()
+})
+
+// pipe the pack stream to your file
+pack.pipe(yourTarball)
+
+yourTarball.on('close', function () {
+  console.log(path + ' has been written')
+  fs.stat(path, function(err, stats) {
+    if (err) throw err
+    console.log(stats)
+    console.log('Got file info successfully!')
+  })
+})
+```
+
+## Performance
+
+[See tar-fs for a performance comparison with node-tar](https://github.com/mafintosh/tar-fs/blob/master/README.md#performance)
+
+# License
+
+MIT
diff --git a/server/node_modules/tar-stream/extract.js b/server/node_modules/tar-stream/extract.js
new file mode 100644
index 0000000..11b13b7
--- /dev/null
+++ b/server/node_modules/tar-stream/extract.js
@@ -0,0 +1,257 @@
+var util = require('util')
+var bl = require('bl')
+var headers = require('./headers')
+
+var Writable = require('readable-stream').Writable
+var PassThrough = require('readable-stream').PassThrough
+
+var noop = function () {}
+
+var overflow = function (size) {
+  size &= 511
+  return size && 512 - size
+}
+
+var emptyStream = function (self, offset) {
+  var s = new Source(self, offset)
+  s.end()
+  return s
+}
+
+var mixinPax = function (header, pax) {
+  if (pax.path) header.name = pax.path
+  if (pax.linkpath) header.linkname = pax.linkpath
+  if (pax.size) header.size = parseInt(pax.size, 10)
+  header.pax = pax
+  return header
+}
+
+var Source = function (self, offset) {
+  this._parent = self
+  this.offset = offset
+  PassThrough.call(this, { autoDestroy: false })
+}
+
+util.inherits(Source, PassThrough)
+
+Source.prototype.destroy = function (err) {
+  this._parent.destroy(err)
+}
+
+var Extract = function (opts) {
+  if (!(this instanceof Extract)) return new Extract(opts)
+  Writable.call(this, opts)
+
+  opts = opts || {}
+
+  this._offset = 0
+  this._buffer = bl()
+  this._missing = 0
+  this._partial = false
+  this._onparse = noop
+  this._header = null
+  this._stream = null
+  this._overflow = null
+  this._cb = null
+  this._locked = false
+  this._destroyed = false
+  this._pax = null
+  this._paxGlobal = null
+  this._gnuLongPath = null
+  this._gnuLongLinkPath = null
+
+  var self = this
+  var b = self._buffer
+
+  var oncontinue = function () {
+    self._continue()
+  }
+
+  var onunlock = function (err) {
+    self._locked = false
+    if (err) return self.destroy(err)
+    if (!self._stream) oncontinue()
+  }
+
+  var onstreamend = function () {
+    self._stream = null
+    var drain = overflow(self._header.size)
+    if (drain) self._parse(drain, ondrain)
+    else self._parse(512, onheader)
+    if (!self._locked) oncontinue()
+  }
+
+  var ondrain = function () {
+    self._buffer.consume(overflow(self._header.size))
+    self._parse(512, onheader)
+    oncontinue()
+  }
+
+  var onpaxglobalheader = function () {
+    var size = self._header.size
+    self._paxGlobal = headers.decodePax(b.slice(0, size))
+    b.consume(size)
+    onstreamend()
+  }
+
+  var onpaxheader = function () {
+    var size = self._header.size
+    self._pax = headers.decodePax(b.slice(0, size))
+    if (self._paxGlobal) self._pax = Object.assign({}, self._paxGlobal, self._pax)
+    b.consume(size)
+    onstreamend()
+  }
+
+  var ongnulongpath = function () {
+    var size = self._header.size
+    this._gnuLongPath = headers.decodeLongPath(b.slice(0, size), opts.filenameEncoding)
+    b.consume(size)
+    onstreamend()
+  }
+
+  var ongnulonglinkpath = function () {
+    var size = self._header.size
+    this._gnuLongLinkPath = headers.decodeLongPath(b.slice(0, size), opts.filenameEncoding)
+    b.consume(size)
+    onstreamend()
+  }
+
+  var onheader = function () {
+    var offset = self._offset
+    var header
+    try {
+      header = self._header = headers.decode(b.slice(0, 512), opts.filenameEncoding, opts.allowUnknownFormat)
+    } catch (err) {
+      self.emit('error', err)
+    }
+    b.consume(512)
+
+    if (!header) {
+      self._parse(512, onheader)
+      oncontinue()
+      return
+    }
+    if (header.type === 'gnu-long-path') {
+      self._parse(header.size, ongnulongpath)
+      oncontinue()
+      return
+    }
+    if (header.type === 'gnu-long-link-path') {
+      self._parse(header.size, ongnulonglinkpath)
+      oncontinue()
+      return
+    }
+    if (header.type === 'pax-global-header') {
+      self._parse(header.size, onpaxglobalheader)
+      oncontinue()
+      return
+    }
+    if (header.type === 'pax-header') {
+      self._parse(header.size, onpaxheader)
+      oncontinue()
+      return
+    }
+
+    if (self._gnuLongPath) {
+      header.name = self._gnuLongPath
+      self._gnuLongPath = null
+    }
+
+    if (self._gnuLongLinkPath) {
+      header.linkname = self._gnuLongLinkPath
+      self._gnuLongLinkPath = null
+    }
+
+    if (self._pax) {
+      self._header = header = mixinPax(header, self._pax)
+      self._pax = null
+    }
+
+    self._locked = true
+
+    if (!header.size || header.type === 'directory') {
+      self._parse(512, onheader)
+      self.emit('entry', header, emptyStream(self, offset), onunlock)
+      return
+    }
+
+    self._stream = new Source(self, offset)
+
+    self.emit('entry', header, self._stream, onunlock)
+    self._parse(header.size, onstreamend)
+    oncontinue()
+  }
+
+  this._onheader = onheader
+  this._parse(512, onheader)
+}
+
+util.inherits(Extract, Writable)
+
+Extract.prototype.destroy = function (err) {
+  if (this._destroyed) return
+  this._destroyed = true
+
+  if (err) this.emit('error', err)
+  this.emit('close')
+  if (this._stream) this._stream.emit('close')
+}
+
+Extract.prototype._parse = function (size, onparse) {
+  if (this._destroyed) return
+  this._offset += size
+  this._missing = size
+  if (onparse === this._onheader) this._partial = false
+  this._onparse = onparse
+}
+
+Extract.prototype._continue = function () {
+  if (this._destroyed) return
+  var cb = this._cb
+  this._cb = noop
+  if (this._overflow) this._write(this._overflow, undefined, cb)
+  else cb()
+}
+
+Extract.prototype._write = function (data, enc, cb) {
+  if (this._destroyed) return
+
+  var s = this._stream
+  var b = this._buffer
+  var missing = this._missing
+  if (data.length) this._partial = true
+
+  // we do not reach end-of-chunk now. just forward it
+
+  if (data.length < missing) {
+    this._missing -= data.length
+    this._overflow = null
+    if (s) return s.write(data, cb)
+    b.append(data)
+    return cb()
+  }
+
+  // end-of-chunk. the parser should call cb.
+
+  this._cb = cb
+  this._missing = 0
+
+  var overflow = null
+  if (data.length > missing) {
+    overflow = data.slice(missing)
+    data = data.slice(0, missing)
+  }
+
+  if (s) s.end(data)
+  else b.append(data)
+
+  this._overflow = overflow
+  this._onparse()
+}
+
+Extract.prototype._final = function (cb) {
+  if (this._partial) return this.destroy(new Error('Unexpected end of data'))
+  cb()
+}
+
+module.exports = Extract
diff --git a/server/node_modules/tar-stream/headers.js b/server/node_modules/tar-stream/headers.js
new file mode 100644
index 0000000..aba4ca4
--- /dev/null
+++ b/server/node_modules/tar-stream/headers.js
@@ -0,0 +1,295 @@
+var alloc = Buffer.alloc
+
+var ZEROS = '0000000000000000000'
+var SEVENS = '7777777777777777777'
+var ZERO_OFFSET = '0'.charCodeAt(0)
+var USTAR_MAGIC = Buffer.from('ustar\x00', 'binary')
+var USTAR_VER = Buffer.from('00', 'binary')
+var GNU_MAGIC = Buffer.from('ustar\x20', 'binary')
+var GNU_VER = Buffer.from('\x20\x00', 'binary')
+var MASK = parseInt('7777', 8)
+var MAGIC_OFFSET = 257
+var VERSION_OFFSET = 263
+
+var clamp = function (index, len, defaultValue) {
+  if (typeof index !== 'number') return defaultValue
+  index = ~~index // Coerce to integer.
+  if (index >= len) return len
+  if (index >= 0) return index
+  index += len
+  if (index >= 0) return index
+  return 0
+}
+
+var toType = function (flag) {
+  switch (flag) {
+    case 0:
+      return 'file'
+    case 1:
+      return 'link'
+    case 2:
+      return 'symlink'
+    case 3:
+      return 'character-device'
+    case 4:
+      return 'block-device'
+    case 5:
+      return 'directory'
+    case 6:
+      return 'fifo'
+    case 7:
+      return 'contiguous-file'
+    case 72:
+      return 'pax-header'
+    case 55:
+      return 'pax-global-header'
+    case 27:
+      return 'gnu-long-link-path'
+    case 28:
+    case 30:
+      return 'gnu-long-path'
+  }
+
+  return null
+}
+
+var toTypeflag = function (flag) {
+  switch (flag) {
+    case 'file':
+      return 0
+    case 'link':
+      return 1
+    case 'symlink':
+      return 2
+    case 'character-device':
+      return 3
+    case 'block-device':
+      return 4
+    case 'directory':
+      return 5
+    case 'fifo':
+      return 6
+    case 'contiguous-file':
+      return 7
+    case 'pax-header':
+      return 72
+  }
+
+  return 0
+}
+
+var indexOf = function (block, num, offset, end) {
+  for (; offset < end; offset++) {
+    if (block[offset] === num) return offset
+  }
+  return end
+}
+
+var cksum = function (block) {
+  var sum = 8 * 32
+  for (var i = 0; i < 148; i++) sum += block[i]
+  for (var j = 156; j < 512; j++) sum += block[j]
+  return sum
+}
+
+var encodeOct = function (val, n) {
+  val = val.toString(8)
+  if (val.length > n) return SEVENS.slice(0, n) + ' '
+  else return ZEROS.slice(0, n - val.length) + val + ' '
+}
+
+/* Copied from the node-tar repo and modified to meet
+ * tar-stream coding standard.
+ *
+ * Source: https://github.com/npm/node-tar/blob/51b6627a1f357d2eb433e7378e5f05e83b7aa6cd/lib/header.js#L349
+ */
+function parse256 (buf) {
+  // first byte MUST be either 80 or FF
+  // 80 for positive, FF for 2's comp
+  var positive
+  if (buf[0] === 0x80) positive = true
+  else if (buf[0] === 0xFF) positive = false
+  else return null
+
+  // build up a base-256 tuple from the least sig to the highest
+  var tuple = []
+  for (var i = buf.length - 1; i > 0; i--) {
+    var byte = buf[i]
+    if (positive) tuple.push(byte)
+    else tuple.push(0xFF - byte)
+  }
+
+  var sum = 0
+  var l = tuple.length
+  for (i = 0; i < l; i++) {
+    sum += tuple[i] * Math.pow(256, i)
+  }
+
+  return positive ? sum : -1 * sum
+}
+
+var decodeOct = function (val, offset, length) {
+  val = val.slice(offset, offset + length)
+  offset = 0
+
+  // If prefixed with 0x80 then parse as a base-256 integer
+  if (val[offset] & 0x80) {
+    return parse256(val)
+  } else {
+    // Older versions of tar can prefix with spaces
+    while (offset < val.length && val[offset] === 32) offset++
+    var end = clamp(indexOf(val, 32, offset, val.length), val.length, val.length)
+    while (offset < end && val[offset] === 0) offset++
+    if (end === offset) return 0
+    return parseInt(val.slice(offset, end).toString(), 8)
+  }
+}
+
+var decodeStr = function (val, offset, length, encoding) {
+  return val.slice(offset, indexOf(val, 0, offset, offset + length)).toString(encoding)
+}
+
+var addLength = function (str) {
+  var len = Buffer.byteLength(str)
+  var digits = Math.floor(Math.log(len) / Math.log(10)) + 1
+  if (len + digits >= Math.pow(10, digits)) digits++
+
+  return (len + digits) + str
+}
+
+exports.decodeLongPath = function (buf, encoding) {
+  return decodeStr(buf, 0, buf.length, encoding)
+}
+
+exports.encodePax = function (opts) { // TODO: encode more stuff in pax
+  var result = ''
+  if (opts.name) result += addLength(' path=' + opts.name + '\n')
+  if (opts.linkname) result += addLength(' linkpath=' + opts.linkname + '\n')
+  var pax = opts.pax
+  if (pax) {
+    for (var key in pax) {
+      result += addLength(' ' + key + '=' + pax[key] + '\n')
+    }
+  }
+  return Buffer.from(result)
+}
+
+exports.decodePax = function (buf) {
+  var result = {}
+
+  while (buf.length) {
+    var i = 0
+    while (i < buf.length && buf[i] !== 32) i++
+    var len = parseInt(buf.slice(0, i).toString(), 10)
+    if (!len) return result
+
+    var b = buf.slice(i + 1, len - 1).toString()
+    var keyIndex = b.indexOf('=')
+    if (keyIndex === -1) return result
+    result[b.slice(0, keyIndex)] = b.slice(keyIndex + 1)
+
+    buf = buf.slice(len)
+  }
+
+  return result
+}
+
+exports.encode = function (opts) {
+  var buf = alloc(512)
+  var name = opts.name
+  var prefix = ''
+
+  if (opts.typeflag === 5 && name[name.length - 1] !== '/') name += '/'
+  if (Buffer.byteLength(name) !== name.length) return null // utf-8
+
+  while (Buffer.byteLength(name) > 100) {
+    var i = name.indexOf('/')
+    if (i === -1) return null
+    prefix += prefix ? '/' + name.slice(0, i) : name.slice(0, i)
+    name = name.slice(i + 1)
+  }
+
+  if (Buffer.byteLength(name) > 100 || Buffer.byteLength(prefix) > 155) return null
+  if (opts.linkname && Buffer.byteLength(opts.linkname) > 100) return null
+
+  buf.write(name)
+  buf.write(encodeOct(opts.mode & MASK, 6), 100)
+  buf.write(encodeOct(opts.uid, 6), 108)
+  buf.write(encodeOct(opts.gid, 6), 116)
+  buf.write(encodeOct(opts.size, 11), 124)
+  buf.write(encodeOct((opts.mtime.getTime() / 1000) | 0, 11), 136)
+
+  buf[156] = ZERO_OFFSET + toTypeflag(opts.type)
+
+  if (opts.linkname) buf.write(opts.linkname, 157)
+
+  USTAR_MAGIC.copy(buf, MAGIC_OFFSET)
+  USTAR_VER.copy(buf, VERSION_OFFSET)
+  if (opts.uname) buf.write(opts.uname, 265)
+  if (opts.gname) buf.write(opts.gname, 297)
+  buf.write(encodeOct(opts.devmajor || 0, 6), 329)
+  buf.write(encodeOct(opts.devminor || 0, 6), 337)
+
+  if (prefix) buf.write(prefix, 345)
+
+  buf.write(encodeOct(cksum(buf), 6), 148)
+
+  return buf
+}
+
+exports.decode = function (buf, filenameEncoding, allowUnknownFormat) {
+  var typeflag = buf[156] === 0 ? 0 : buf[156] - ZERO_OFFSET
+
+  var name = decodeStr(buf, 0, 100, filenameEncoding)
+  var mode = decodeOct(buf, 100, 8)
+  var uid = decodeOct(buf, 108, 8)
+  var gid = decodeOct(buf, 116, 8)
+  var size = decodeOct(buf, 124, 12)
+  var mtime = decodeOct(buf, 136, 12)
+  var type = toType(typeflag)
+  var linkname = buf[157] === 0 ? null : decodeStr(buf, 157, 100, filenameEncoding)
+  var uname = decodeStr(buf, 265, 32)
+  var gname = decodeStr(buf, 297, 32)
+  var devmajor = decodeOct(buf, 329, 8)
+  var devminor = decodeOct(buf, 337, 8)
+
+  var c = cksum(buf)
+
+  // checksum is still initial value if header was null.
+  if (c === 8 * 32) return null
+
+  // valid checksum
+  if (c !== decodeOct(buf, 148, 8)) throw new Error('Invalid tar header. Maybe the tar is corrupted or it needs to be gunzipped?')
+
+  if (USTAR_MAGIC.compare(buf, MAGIC_OFFSET, MAGIC_OFFSET + 6) === 0) {
+    // ustar (posix) format.
+    // prepend prefix, if present.
+    if (buf[345]) name = decodeStr(buf, 345, 155, filenameEncoding) + '/' + name
+  } else if (GNU_MAGIC.compare(buf, MAGIC_OFFSET, MAGIC_OFFSET + 6) === 0 &&
+             GNU_VER.compare(buf, VERSION_OFFSET, VERSION_OFFSET + 2) === 0) {
+    // 'gnu'/'oldgnu' format. Similar to ustar, but has support for incremental and
+    // multi-volume tarballs.
+  } else {
+    if (!allowUnknownFormat) {
+      throw new Error('Invalid tar header: unknown format.')
+    }
+  }
+
+  // to support old tar versions that use trailing / to indicate dirs
+  if (typeflag === 0 && name && name[name.length - 1] === '/') typeflag = 5
+
+  return {
+    name,
+    mode,
+    uid,
+    gid,
+    size,
+    mtime: new Date(1000 * mtime),
+    type,
+    linkname,
+    uname,
+    gname,
+    devmajor,
+    devminor
+  }
+}
diff --git a/server/node_modules/tar-stream/index.js b/server/node_modules/tar-stream/index.js
new file mode 100644
index 0000000..6481704
--- /dev/null
+++ b/server/node_modules/tar-stream/index.js
@@ -0,0 +1,2 @@
+exports.extract = require('./extract')
+exports.pack = require('./pack')
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/CONTRIBUTING.md b/server/node_modules/tar-stream/node_modules/readable-stream/CONTRIBUTING.md
new file mode 100644
index 0000000..f478d58
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/CONTRIBUTING.md
@@ -0,0 +1,38 @@
+# Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+* (a) The contribution was created in whole or in part by me and I
+  have the right to submit it under the open source license
+  indicated in the file; or
+
+* (b) The contribution is based upon previous work that, to the best
+  of my knowledge, is covered under an appropriate open source
+  license and I have the right under that license to submit that
+  work with modifications, whether created in whole or in part
+  by me, under the same open source license (unless I am
+  permitted to submit under a different license), as indicated
+  in the file; or
+
+* (c) The contribution was provided directly to me by some other
+  person who certified (a), (b) or (c) and I have not modified
+  it.
+
+* (d) I understand and agree that this project and the contribution
+  are public and that a record of the contribution (including all
+  personal information I submit with it, including my sign-off) is
+  maintained indefinitely and may be redistributed consistent with
+  this project or the open source license(s) involved.
+
+## Moderation Policy
+
+The [Node.js Moderation Policy] applies to this WG.
+
+## Code of Conduct
+
+The [Node.js Code of Conduct][] applies to this WG.
+
+[Node.js Code of Conduct]:
+https://github.com/nodejs/node/blob/master/CODE_OF_CONDUCT.md
+[Node.js Moderation Policy]:
+https://github.com/nodejs/TSC/blob/master/Moderation-Policy.md
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/GOVERNANCE.md b/server/node_modules/tar-stream/node_modules/readable-stream/GOVERNANCE.md
new file mode 100644
index 0000000..16ffb93
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/GOVERNANCE.md
@@ -0,0 +1,136 @@
+### Streams Working Group
+
+The Node.js Streams is jointly governed by a Working Group
+(WG)
+that is responsible for high-level guidance of the project.
+
+The WG has final authority over this project including:
+
+* Technical direction
+* Project governance and process (including this policy)
+* Contribution policy
+* GitHub repository hosting
+* Conduct guidelines
+* Maintaining the list of additional Collaborators
+
+For the current list of WG members, see the project
+[README.md](./README.md#current-project-team-members).
+
+### Collaborators
+
+The readable-stream GitHub repository is
+maintained by the WG and additional Collaborators who are added by the
+WG on an ongoing basis.
+
+Individuals making significant and valuable contributions are made
+Collaborators and given commit-access to the project. These
+individuals are identified by the WG and their addition as
+Collaborators is discussed during the WG meeting.
+
+_Note:_ If you make a significant contribution and are not considered
+for commit-access log an issue or contact a WG member directly and it
+will be brought up in the next WG meeting.
+
+Modifications of the contents of the readable-stream repository are
+made on
+a collaborative basis. Anybody with a GitHub account may propose a
+modification via pull request and it will be considered by the project
+Collaborators. All pull requests must be reviewed and accepted by a
+Collaborator with sufficient expertise who is able to take full
+responsibility for the change. In the case of pull requests proposed
+by an existing Collaborator, an additional Collaborator is required
+for sign-off. Consensus should be sought if additional Collaborators
+participate and there is disagreement around a particular
+modification. See _Consensus Seeking Process_ below for further detail
+on the consensus model used for governance.
+
+Collaborators may opt to elevate significant or controversial
+modifications, or modifications that have not found consensus to the
+WG for discussion by assigning the ***WG-agenda*** tag to a pull
+request or issue. The WG should serve as the final arbiter where
+required.
+
+For the current list of Collaborators, see the project
+[README.md](./README.md#members).
+
+### WG Membership
+
+WG seats are not time-limited.  There is no fixed size of the WG.
+However, the expected target is between 6 and 12, to ensure adequate
+coverage of important areas of expertise, balanced with the ability to
+make decisions efficiently.
+
+There is no specific set of requirements or qualifications for WG
+membership beyond these rules.
+
+The WG may add additional members to the WG by unanimous consensus.
+
+A WG member may be removed from the WG by voluntary resignation, or by
+unanimous consensus of all other WG members.
+
+Changes to WG membership should be posted in the agenda, and may be
+suggested as any other agenda item (see "WG Meetings" below).
+
+If an addition or removal is proposed during a meeting, and the full
+WG is not in attendance to participate, then the addition or removal
+is added to the agenda for the subsequent meeting.  This is to ensure
+that all members are given the opportunity to participate in all
+membership decisions.  If a WG member is unable to attend a meeting
+where a planned membership decision is being made, then their consent
+is assumed.
+
+No more than 1/3 of the WG members may be affiliated with the same
+employer.  If removal or resignation of a WG member, or a change of
+employment by a WG member, creates a situation where more than 1/3 of
+the WG membership shares an employer, then the situation must be
+immediately remedied by the resignation or removal of one or more WG
+members affiliated with the over-represented employer(s).
+
+### WG Meetings
+
+The WG meets occasionally on a Google Hangout On Air. A designated moderator
+approved by the WG runs the meeting. Each meeting should be
+published to YouTube.
+
+Items are added to the WG agenda that are considered contentious or
+are modifications of governance, contribution policy, WG membership,
+or release process.
+
+The intention of the agenda is not to approve or review all patches;
+that should happen continuously on GitHub and be handled by the larger
+group of Collaborators.
+
+Any community member or contributor can ask that something be added to
+the next meeting's agenda by logging a GitHub Issue. Any Collaborator,
+WG member or the moderator can add the item to the agenda by adding
+the ***WG-agenda*** tag to the issue.
+
+Prior to each WG meeting the moderator will share the Agenda with
+members of the WG. WG members can add any items they like to the
+agenda at the beginning of each meeting. The moderator and the WG
+cannot veto or remove items.
+
+The WG may invite persons or representatives from certain projects to
+participate in a non-voting capacity.
+
+The moderator is responsible for summarizing the discussion of each
+agenda item and sends it as a pull request after the meeting.
+
+### Consensus Seeking Process
+
+The WG follows a
+[Consensus
+Seeking](http://en.wikipedia.org/wiki/Consensus-seeking_decision-making)
+decision-making model.
+
+When an agenda item has appeared to reach a consensus the moderator
+will ask "Does anyone object?" as a final call for dissent from the
+consensus.
+
+If an agenda item cannot reach a consensus a WG member can call for
+either a closing vote or a vote to table the issue to the next
+meeting. The call for a vote must be seconded by a majority of the WG
+or else the discussion will continue. Simple majority wins.
+
+Note that changes to WG membership require a majority consensus.  See
+"WG Membership" above.
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/LICENSE b/server/node_modules/tar-stream/node_modules/readable-stream/LICENSE
new file mode 100644
index 0000000..2873b3b
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/LICENSE
@@ -0,0 +1,47 @@
+Node.js is licensed for use as follows:
+
+"""
+Copyright Node.js contributors. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
+
+This license applies to parts of Node.js originating from the
+https://github.com/joyent/node repository:
+
+"""
+Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+"""
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/README.md b/server/node_modules/tar-stream/node_modules/readable-stream/README.md
new file mode 100644
index 0000000..19117c1
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/README.md
@@ -0,0 +1,106 @@
+# readable-stream
+
+***Node.js core streams for userland*** [![Build Status](https://travis-ci.com/nodejs/readable-stream.svg?branch=master)](https://travis-ci.com/nodejs/readable-stream)
+
+
+[![NPM](https://nodei.co/npm/readable-stream.png?downloads=true&downloadRank=true)](https://nodei.co/npm/readable-stream/)
+[![NPM](https://nodei.co/npm-dl/readable-stream.png?&months=6&height=3)](https://nodei.co/npm/readable-stream/)
+
+
+[![Sauce Test Status](https://saucelabs.com/browser-matrix/readabe-stream.svg)](https://saucelabs.com/u/readabe-stream)
+
+```bash
+npm install --save readable-stream
+```
+
+This package is a mirror of the streams implementations in Node.js.
+
+Full documentation may be found on the [Node.js website](https://nodejs.org/dist/v10.18.1/docs/api/stream.html).
+
+If you want to guarantee a stable streams base, regardless of what version of
+Node you, or the users of your libraries are using, use **readable-stream** *only* and avoid the *"stream"* module in Node-core, for background see [this blogpost](http://r.va.gg/2014/06/why-i-dont-use-nodes-core-stream-module.html).
+
+As of version 2.0.0 **readable-stream** uses semantic versioning.
+
+## Version 3.x.x
+
+v3.x.x of `readable-stream` is a cut from Node 10. This version supports Node 6, 8, and 10, as well as evergreen browsers, IE 11 and latest Safari. The breaking changes introduced by v3 are composed by the combined breaking changes in [Node v9](https://nodejs.org/en/blog/release/v9.0.0/) and [Node v10](https://nodejs.org/en/blog/release/v10.0.0/), as follows:
+
+1. Error codes: https://github.com/nodejs/node/pull/13310,
+   https://github.com/nodejs/node/pull/13291,
+   https://github.com/nodejs/node/pull/16589,
+   https://github.com/nodejs/node/pull/15042,
+   https://github.com/nodejs/node/pull/15665,
+   https://github.com/nodejs/readable-stream/pull/344
+2. 'readable' have precedence over flowing
+   https://github.com/nodejs/node/pull/18994
+3. make virtual methods errors consistent
+   https://github.com/nodejs/node/pull/18813
+4. updated streams error handling
+   https://github.com/nodejs/node/pull/18438
+5. writable.end should return this.
+   https://github.com/nodejs/node/pull/18780
+6. readable continues to read when push('')
+   https://github.com/nodejs/node/pull/18211
+7. add custom inspect to BufferList
+   https://github.com/nodejs/node/pull/17907
+8. always defer 'readable' with nextTick
+   https://github.com/nodejs/node/pull/17979
+
+## Version 2.x.x
+v2.x.x of `readable-stream` is a cut of the stream module from Node 8 (there have been no semver-major changes from Node 4 to 8). This version supports all Node.js versions from 0.8, as well as evergreen browsers and IE 10 & 11.
+
+### Big Thanks
+
+Cross-browser Testing Platform and Open Source <3 Provided by [Sauce Labs][sauce]
+
+# Usage
+
+You can swap your `require('stream')` with `require('readable-stream')`
+without any changes, if you are just using one of the main classes and
+functions.
+
+```js
+const {
+  Readable,
+  Writable,
+  Transform,
+  Duplex,
+  pipeline,
+  finished
+} = require('readable-stream')
+````
+
+Note that `require('stream')` will return `Stream`, while
+`require('readable-stream')` will return `Readable`. We discourage using
+whatever is exported directly, but rather use one of the properties as
+shown in the example above.
+
+# Streams Working Group
+
+`readable-stream` is maintained by the Streams Working Group, which
+oversees the development and maintenance of the Streams API within
+Node.js. The responsibilities of the Streams Working Group include:
+
+* Addressing stream issues on the Node.js issue tracker.
+* Authoring and editing stream documentation within the Node.js project.
+* Reviewing changes to stream subclasses within the Node.js project.
+* Redirecting changes to streams from the Node.js project to this
+  project.
+* Assisting in the implementation of stream providers within Node.js.
+* Recommending versions of `readable-stream` to be included in Node.js.
+* Messaging about the future of streams to give the community advance
+  notice of changes.
+
+<a name="members"></a>
+## Team Members
+
+* **Calvin Metcalf** ([@calvinmetcalf](https://github.com/calvinmetcalf)) <calvin.metcalf@gmail.com>
+  - Release GPG key: F3EF5F62A87FC27A22E643F714CE4FF5015AA242
+* **Mathias Buus** ([@mafintosh](https://github.com/mafintosh)) <mathiasbuus@gmail.com>
+* **Matteo Collina** ([@mcollina](https://github.com/mcollina)) <matteo.collina@gmail.com>
+  - Release GPG key: 3ABC01543F22DD2239285CDD818674489FBC127E
+* **Irina Shestak** ([@lrlna](https://github.com/lrlna)) <shestak.irina@gmail.com>
+* **Yoshua Wyuts** ([@yoshuawuyts](https://github.com/yoshuawuyts)) <yoshuawuyts@gmail.com>
+
+[sauce]: https://saucelabs.com
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/errors-browser.js b/server/node_modules/tar-stream/node_modules/readable-stream/errors-browser.js
new file mode 100644
index 0000000..fb8e73e
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/errors-browser.js
@@ -0,0 +1,127 @@
+'use strict';
+
+function _inheritsLoose(subClass, superClass) { subClass.prototype = Object.create(superClass.prototype); subClass.prototype.constructor = subClass; subClass.__proto__ = superClass; }
+
+var codes = {};
+
+function createErrorType(code, message, Base) {
+  if (!Base) {
+    Base = Error;
+  }
+
+  function getMessage(arg1, arg2, arg3) {
+    if (typeof message === 'string') {
+      return message;
+    } else {
+      return message(arg1, arg2, arg3);
+    }
+  }
+
+  var NodeError =
+  /*#__PURE__*/
+  function (_Base) {
+    _inheritsLoose(NodeError, _Base);
+
+    function NodeError(arg1, arg2, arg3) {
+      return _Base.call(this, getMessage(arg1, arg2, arg3)) || this;
+    }
+
+    return NodeError;
+  }(Base);
+
+  NodeError.prototype.name = Base.name;
+  NodeError.prototype.code = code;
+  codes[code] = NodeError;
+} // https://github.com/nodejs/node/blob/v10.8.0/lib/internal/errors.js
+
+
+function oneOf(expected, thing) {
+  if (Array.isArray(expected)) {
+    var len = expected.length;
+    expected = expected.map(function (i) {
+      return String(i);
+    });
+
+    if (len > 2) {
+      return "one of ".concat(thing, " ").concat(expected.slice(0, len - 1).join(', '), ", or ") + expected[len - 1];
+    } else if (len === 2) {
+      return "one of ".concat(thing, " ").concat(expected[0], " or ").concat(expected[1]);
+    } else {
+      return "of ".concat(thing, " ").concat(expected[0]);
+    }
+  } else {
+    return "of ".concat(thing, " ").concat(String(expected));
+  }
+} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
+
+
+function startsWith(str, search, pos) {
+  return str.substr(!pos || pos < 0 ? 0 : +pos, search.length) === search;
+} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith
+
+
+function endsWith(str, search, this_len) {
+  if (this_len === undefined || this_len > str.length) {
+    this_len = str.length;
+  }
+
+  return str.substring(this_len - search.length, this_len) === search;
+} // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes
+
+
+function includes(str, search, start) {
+  if (typeof start !== 'number') {
+    start = 0;
+  }
+
+  if (start + search.length > str.length) {
+    return false;
+  } else {
+    return str.indexOf(search, start) !== -1;
+  }
+}
+
+createErrorType('ERR_INVALID_OPT_VALUE', function (name, value) {
+  return 'The value "' + value + '" is invalid for option "' + name + '"';
+}, TypeError);
+createErrorType('ERR_INVALID_ARG_TYPE', function (name, expected, actual) {
+  // determiner: 'must be' or 'must not be'
+  var determiner;
+
+  if (typeof expected === 'string' && startsWith(expected, 'not ')) {
+    determiner = 'must not be';
+    expected = expected.replace(/^not /, '');
+  } else {
+    determiner = 'must be';
+  }
+
+  var msg;
+
+  if (endsWith(name, ' argument')) {
+    // For cases like 'first argument'
+    msg = "The ".concat(name, " ").concat(determiner, " ").concat(oneOf(expected, 'type'));
+  } else {
+    var type = includes(name, '.') ? 'property' : 'argument';
+    msg = "The \"".concat(name, "\" ").concat(type, " ").concat(determiner, " ").concat(oneOf(expected, 'type'));
+  }
+
+  msg += ". Received type ".concat(typeof actual);
+  return msg;
+}, TypeError);
+createErrorType('ERR_STREAM_PUSH_AFTER_EOF', 'stream.push() after EOF');
+createErrorType('ERR_METHOD_NOT_IMPLEMENTED', function (name) {
+  return 'The ' + name + ' method is not implemented';
+});
+createErrorType('ERR_STREAM_PREMATURE_CLOSE', 'Premature close');
+createErrorType('ERR_STREAM_DESTROYED', function (name) {
+  return 'Cannot call ' + name + ' after a stream was destroyed';
+});
+createErrorType('ERR_MULTIPLE_CALLBACK', 'Callback called multiple times');
+createErrorType('ERR_STREAM_CANNOT_PIPE', 'Cannot pipe, not readable');
+createErrorType('ERR_STREAM_WRITE_AFTER_END', 'write after end');
+createErrorType('ERR_STREAM_NULL_VALUES', 'May not write null values to stream', TypeError);
+createErrorType('ERR_UNKNOWN_ENCODING', function (arg) {
+  return 'Unknown encoding: ' + arg;
+}, TypeError);
+createErrorType('ERR_STREAM_UNSHIFT_AFTER_END_EVENT', 'stream.unshift() after end event');
+module.exports.codes = codes;
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/errors.js b/server/node_modules/tar-stream/node_modules/readable-stream/errors.js
new file mode 100644
index 0000000..8471526
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/errors.js
@@ -0,0 +1,116 @@
+'use strict';
+
+const codes = {};
+
+function createErrorType(code, message, Base) {
+  if (!Base) {
+    Base = Error
+  }
+
+  function getMessage (arg1, arg2, arg3) {
+    if (typeof message === 'string') {
+      return message
+    } else {
+      return message(arg1, arg2, arg3)
+    }
+  }
+
+  class NodeError extends Base {
+    constructor (arg1, arg2, arg3) {
+      super(getMessage(arg1, arg2, arg3));
+    }
+  }
+
+  NodeError.prototype.name = Base.name;
+  NodeError.prototype.code = code;
+
+  codes[code] = NodeError;
+}
+
+// https://github.com/nodejs/node/blob/v10.8.0/lib/internal/errors.js
+function oneOf(expected, thing) {
+  if (Array.isArray(expected)) {
+    const len = expected.length;
+    expected = expected.map((i) => String(i));
+    if (len > 2) {
+      return `one of ${thing} ${expected.slice(0, len - 1).join(', ')}, or ` +
+             expected[len - 1];
+    } else if (len === 2) {
+      return `one of ${thing} ${expected[0]} or ${expected[1]}`;
+    } else {
+      return `of ${thing} ${expected[0]}`;
+    }
+  } else {
+    return `of ${thing} ${String(expected)}`;
+  }
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
+function startsWith(str, search, pos) {
+	return str.substr(!pos || pos < 0 ? 0 : +pos, search.length) === search;
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith
+function endsWith(str, search, this_len) {
+	if (this_len === undefined || this_len > str.length) {
+		this_len = str.length;
+	}
+	return str.substring(this_len - search.length, this_len) === search;
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes
+function includes(str, search, start) {
+  if (typeof start !== 'number') {
+    start = 0;
+  }
+
+  if (start + search.length > str.length) {
+    return false;
+  } else {
+    return str.indexOf(search, start) !== -1;
+  }
+}
+
+createErrorType('ERR_INVALID_OPT_VALUE', function (name, value) {
+  return 'The value "' + value + '" is invalid for option "' + name + '"'
+}, TypeError);
+createErrorType('ERR_INVALID_ARG_TYPE', function (name, expected, actual) {
+  // determiner: 'must be' or 'must not be'
+  let determiner;
+  if (typeof expected === 'string' && startsWith(expected, 'not ')) {
+    determiner = 'must not be';
+    expected = expected.replace(/^not /, '');
+  } else {
+    determiner = 'must be';
+  }
+
+  let msg;
+  if (endsWith(name, ' argument')) {
+    // For cases like 'first argument'
+    msg = `The ${name} ${determiner} ${oneOf(expected, 'type')}`;
+  } else {
+    const type = includes(name, '.') ? 'property' : 'argument';
+    msg = `The "${name}" ${type} ${determiner} ${oneOf(expected, 'type')}`;
+  }
+
+  msg += `. Received type ${typeof actual}`;
+  return msg;
+}, TypeError);
+createErrorType('ERR_STREAM_PUSH_AFTER_EOF', 'stream.push() after EOF');
+createErrorType('ERR_METHOD_NOT_IMPLEMENTED', function (name) {
+  return 'The ' + name + ' method is not implemented'
+});
+createErrorType('ERR_STREAM_PREMATURE_CLOSE', 'Premature close');
+createErrorType('ERR_STREAM_DESTROYED', function (name) {
+  return 'Cannot call ' + name + ' after a stream was destroyed';
+});
+createErrorType('ERR_MULTIPLE_CALLBACK', 'Callback called multiple times');
+createErrorType('ERR_STREAM_CANNOT_PIPE', 'Cannot pipe, not readable');
+createErrorType('ERR_STREAM_WRITE_AFTER_END', 'write after end');
+createErrorType('ERR_STREAM_NULL_VALUES', 'May not write null values to stream', TypeError);
+createErrorType('ERR_UNKNOWN_ENCODING', function (arg) {
+  return 'Unknown encoding: ' + arg
+}, TypeError);
+createErrorType('ERR_STREAM_UNSHIFT_AFTER_END_EVENT', 'stream.unshift() after end event');
+
+module.exports.codes = codes;
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/experimentalWarning.js b/server/node_modules/tar-stream/node_modules/readable-stream/experimentalWarning.js
new file mode 100644
index 0000000..78e8414
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/experimentalWarning.js
@@ -0,0 +1,17 @@
+'use strict'
+
+var experimentalWarnings = new Set();
+
+function emitExperimentalWarning(feature) {
+  if (experimentalWarnings.has(feature)) return;
+  var msg = feature + ' is an experimental feature. This feature could ' +
+       'change at any time';
+  experimentalWarnings.add(feature);
+  process.emitWarning(msg, 'ExperimentalWarning');
+}
+
+function noop() {}
+
+module.exports.emitExperimentalWarning = process.emitWarning
+  ? emitExperimentalWarning
+  : noop;
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_duplex.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_duplex.js
new file mode 100644
index 0000000..19abfa6
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_duplex.js
@@ -0,0 +1,126 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a duplex stream is just a stream that is both readable and writable.
+// Since JS doesn't have multiple prototypal inheritance, this class
+// prototypally inherits from Readable, and then parasitically from
+// Writable.
+
+'use strict';
+
+/*<replacement>*/
+var objectKeys = Object.keys || function (obj) {
+  var keys = [];
+  for (var key in obj) keys.push(key);
+  return keys;
+};
+/*</replacement>*/
+
+module.exports = Duplex;
+var Readable = require('./_stream_readable');
+var Writable = require('./_stream_writable');
+require('inherits')(Duplex, Readable);
+{
+  // Allow the keys array to be GC'ed.
+  var keys = objectKeys(Writable.prototype);
+  for (var v = 0; v < keys.length; v++) {
+    var method = keys[v];
+    if (!Duplex.prototype[method]) Duplex.prototype[method] = Writable.prototype[method];
+  }
+}
+function Duplex(options) {
+  if (!(this instanceof Duplex)) return new Duplex(options);
+  Readable.call(this, options);
+  Writable.call(this, options);
+  this.allowHalfOpen = true;
+  if (options) {
+    if (options.readable === false) this.readable = false;
+    if (options.writable === false) this.writable = false;
+    if (options.allowHalfOpen === false) {
+      this.allowHalfOpen = false;
+      this.once('end', onend);
+    }
+  }
+}
+Object.defineProperty(Duplex.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.highWaterMark;
+  }
+});
+Object.defineProperty(Duplex.prototype, 'writableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState && this._writableState.getBuffer();
+  }
+});
+Object.defineProperty(Duplex.prototype, 'writableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.length;
+  }
+});
+
+// the no-half-open enforcer
+function onend() {
+  // If the writable side ended, then we're ok.
+  if (this._writableState.ended) return;
+
+  // no more data can be written.
+  // But allow more writes to happen in this tick.
+  process.nextTick(onEndNT, this);
+}
+function onEndNT(self) {
+  self.end();
+}
+Object.defineProperty(Duplex.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed && this._writableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (this._readableState === undefined || this._writableState === undefined) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+    this._writableState.destroyed = value;
+  }
+});
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_passthrough.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_passthrough.js
new file mode 100644
index 0000000..24a6bdd
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_passthrough.js
@@ -0,0 +1,37 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a passthrough stream.
+// basically just the most minimal sort of Transform stream.
+// Every written chunk gets output as-is.
+
+'use strict';
+
+module.exports = PassThrough;
+var Transform = require('./_stream_transform');
+require('inherits')(PassThrough, Transform);
+function PassThrough(options) {
+  if (!(this instanceof PassThrough)) return new PassThrough(options);
+  Transform.call(this, options);
+}
+PassThrough.prototype._transform = function (chunk, encoding, cb) {
+  cb(null, chunk);
+};
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_readable.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_readable.js
new file mode 100644
index 0000000..df1f608
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_readable.js
@@ -0,0 +1,1027 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+
+module.exports = Readable;
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Readable.ReadableState = ReadableState;
+
+/*<replacement>*/
+var EE = require('events').EventEmitter;
+var EElistenerCount = function EElistenerCount(emitter, type) {
+  return emitter.listeners(type).length;
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+var Buffer = require('buffer').Buffer;
+var OurUint8Array = (typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : typeof self !== 'undefined' ? self : {}).Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+
+/*<replacement>*/
+var debugUtil = require('util');
+var debug;
+if (debugUtil && debugUtil.debuglog) {
+  debug = debugUtil.debuglog('stream');
+} else {
+  debug = function debug() {};
+}
+/*</replacement>*/
+
+var BufferList = require('./internal/streams/buffer_list');
+var destroyImpl = require('./internal/streams/destroy');
+var _require = require('./internal/streams/state'),
+  getHighWaterMark = _require.getHighWaterMark;
+var _require$codes = require('../errors').codes,
+  ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
+  ERR_STREAM_PUSH_AFTER_EOF = _require$codes.ERR_STREAM_PUSH_AFTER_EOF,
+  ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_STREAM_UNSHIFT_AFTER_END_EVENT = _require$codes.ERR_STREAM_UNSHIFT_AFTER_END_EVENT;
+
+// Lazy loaded to improve the startup performance.
+var StringDecoder;
+var createReadableStreamAsyncIterator;
+var from;
+require('inherits')(Readable, Stream);
+var errorOrDestroy = destroyImpl.errorOrDestroy;
+var kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
+function prependListener(emitter, event, fn) {
+  // Sadly this is not cacheable as some libraries bundle their own
+  // event emitter implementation with them.
+  if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn);
+
+  // This is a hack to make sure that our error handler is attached before any
+  // userland ones.  NEVER DO THIS. This is here only because this code needs
+  // to continue to work with older versions of Node.js that do not include
+  // the prependListener() method. The goal is to eventually remove this hack.
+  if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (Array.isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
+}
+function ReadableState(options, stream, isDuplex) {
+  Duplex = Duplex || require('./_stream_duplex');
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream.
+  // These options can be provided separately as readableXXX and writableXXX.
+  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex;
+
+  // object stream flag. Used to make read(n) ignore n and to
+  // make all the buffer merging and length checks go away
+  this.objectMode = !!options.objectMode;
+  if (isDuplex) this.objectMode = this.objectMode || !!options.readableObjectMode;
+
+  // the point at which it stops calling _read() to fill the buffer
+  // Note: 0 is a valid value, means "don't call _read preemptively ever"
+  this.highWaterMark = getHighWaterMark(this, options, 'readableHighWaterMark', isDuplex);
+
+  // A linked list is used to store data chunks instead of an array because the
+  // linked list can remove elements from the beginning faster than
+  // array.shift()
+  this.buffer = new BufferList();
+  this.length = 0;
+  this.pipes = null;
+  this.pipesCount = 0;
+  this.flowing = null;
+  this.ended = false;
+  this.endEmitted = false;
+  this.reading = false;
+
+  // a flag to be able to tell if the event 'readable'/'data' is emitted
+  // immediately, or on a later tick.  We set this to true at first, because
+  // any actions that shouldn't happen until "later" should generally also
+  // not happen before the first read call.
+  this.sync = true;
+
+  // whenever we return null, then we set a flag to say
+  // that we're awaiting a 'readable' event emission.
+  this.needReadable = false;
+  this.emittedReadable = false;
+  this.readableListening = false;
+  this.resumeScheduled = false;
+  this.paused = true;
+
+  // Should close be emitted on destroy. Defaults to true.
+  this.emitClose = options.emitClose !== false;
+
+  // Should .destroy() be called after 'end' (and potentially 'finish')
+  this.autoDestroy = !!options.autoDestroy;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // the number of writers that are awaiting a drain event in .pipe()s
+  this.awaitDrain = 0;
+
+  // if true, a maybeReadMore has been scheduled
+  this.readingMore = false;
+  this.decoder = null;
+  this.encoding = null;
+  if (options.encoding) {
+    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+    this.decoder = new StringDecoder(options.encoding);
+    this.encoding = options.encoding;
+  }
+}
+function Readable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+  if (!(this instanceof Readable)) return new Readable(options);
+
+  // Checking for a Stream.Duplex instance is faster here instead of inside
+  // the ReadableState constructor, at least with V8 6.5
+  var isDuplex = this instanceof Duplex;
+  this._readableState = new ReadableState(options, this, isDuplex);
+
+  // legacy
+  this.readable = true;
+  if (options) {
+    if (typeof options.read === 'function') this._read = options.read;
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+  }
+  Stream.call(this);
+}
+Object.defineProperty(Readable.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._readableState === undefined) {
+      return false;
+    }
+    return this._readableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._readableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._readableState.destroyed = value;
+  }
+});
+Readable.prototype.destroy = destroyImpl.destroy;
+Readable.prototype._undestroy = destroyImpl.undestroy;
+Readable.prototype._destroy = function (err, cb) {
+  cb(err);
+};
+
+// Manually shove something into the read() buffer.
+// This returns true if the highWaterMark has not been hit yet,
+// similar to how Writable.write() returns true if you should
+// write() some more.
+Readable.prototype.push = function (chunk, encoding) {
+  var state = this._readableState;
+  var skipChunkCheck;
+  if (!state.objectMode) {
+    if (typeof chunk === 'string') {
+      encoding = encoding || state.defaultEncoding;
+      if (encoding !== state.encoding) {
+        chunk = Buffer.from(chunk, encoding);
+        encoding = '';
+      }
+      skipChunkCheck = true;
+    }
+  } else {
+    skipChunkCheck = true;
+  }
+  return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
+};
+
+// Unshift should *always* be something directly out of read()
+Readable.prototype.unshift = function (chunk) {
+  return readableAddChunk(this, chunk, null, true, false);
+};
+function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
+  debug('readableAddChunk', chunk);
+  var state = stream._readableState;
+  if (chunk === null) {
+    state.reading = false;
+    onEofChunk(stream, state);
+  } else {
+    var er;
+    if (!skipChunkCheck) er = chunkInvalid(state, chunk);
+    if (er) {
+      errorOrDestroy(stream, er);
+    } else if (state.objectMode || chunk && chunk.length > 0) {
+      if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
+        chunk = _uint8ArrayToBuffer(chunk);
+      }
+      if (addToFront) {
+        if (state.endEmitted) errorOrDestroy(stream, new ERR_STREAM_UNSHIFT_AFTER_END_EVENT());else addChunk(stream, state, chunk, true);
+      } else if (state.ended) {
+        errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
+      } else if (state.destroyed) {
+        return false;
+      } else {
+        state.reading = false;
+        if (state.decoder && !encoding) {
+          chunk = state.decoder.write(chunk);
+          if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
+        } else {
+          addChunk(stream, state, chunk, false);
+        }
+      }
+    } else if (!addToFront) {
+      state.reading = false;
+      maybeReadMore(stream, state);
+    }
+  }
+
+  // We can push more data if we are below the highWaterMark.
+  // Also, if we have no data yet, we can stand some more bytes.
+  // This is to work around cases where hwm=0, such as the repl.
+  return !state.ended && (state.length < state.highWaterMark || state.length === 0);
+}
+function addChunk(stream, state, chunk, addToFront) {
+  if (state.flowing && state.length === 0 && !state.sync) {
+    state.awaitDrain = 0;
+    stream.emit('data', chunk);
+  } else {
+    // update the buffer info.
+    state.length += state.objectMode ? 1 : chunk.length;
+    if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);
+    if (state.needReadable) emitReadable(stream);
+  }
+  maybeReadMore(stream, state);
+}
+function chunkInvalid(state, chunk) {
+  var er;
+  if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
+    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer', 'Uint8Array'], chunk);
+  }
+  return er;
+}
+Readable.prototype.isPaused = function () {
+  return this._readableState.flowing === false;
+};
+
+// backwards compatibility.
+Readable.prototype.setEncoding = function (enc) {
+  if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+  var decoder = new StringDecoder(enc);
+  this._readableState.decoder = decoder;
+  // If setEncoding(null), decoder.encoding equals utf8
+  this._readableState.encoding = this._readableState.decoder.encoding;
+
+  // Iterate over current buffer to convert already stored Buffers:
+  var p = this._readableState.buffer.head;
+  var content = '';
+  while (p !== null) {
+    content += decoder.write(p.data);
+    p = p.next;
+  }
+  this._readableState.buffer.clear();
+  if (content !== '') this._readableState.buffer.push(content);
+  this._readableState.length = content.length;
+  return this;
+};
+
+// Don't raise the hwm > 1GB
+var MAX_HWM = 0x40000000;
+function computeNewHighWaterMark(n) {
+  if (n >= MAX_HWM) {
+    // TODO(ronag): Throw ERR_VALUE_OUT_OF_RANGE.
+    n = MAX_HWM;
+  } else {
+    // Get the next highest power of 2 to prevent increasing hwm excessively in
+    // tiny amounts
+    n--;
+    n |= n >>> 1;
+    n |= n >>> 2;
+    n |= n >>> 4;
+    n |= n >>> 8;
+    n |= n >>> 16;
+    n++;
+  }
+  return n;
+}
+
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function howMuchToRead(n, state) {
+  if (n <= 0 || state.length === 0 && state.ended) return 0;
+  if (state.objectMode) return 1;
+  if (n !== n) {
+    // Only flow one buffer at a time
+    if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
+  }
+  // If we're asking for more than the current hwm, then raise the hwm.
+  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
+  if (n <= state.length) return n;
+  // Don't have enough
+  if (!state.ended) {
+    state.needReadable = true;
+    return 0;
+  }
+  return state.length;
+}
+
+// you can override either this method, or the async _read(n) below.
+Readable.prototype.read = function (n) {
+  debug('read', n);
+  n = parseInt(n, 10);
+  var state = this._readableState;
+  var nOrig = n;
+  if (n !== 0) state.emittedReadable = false;
+
+  // if we're doing read(0) to trigger a readable event, but we
+  // already have a bunch of data in the buffer, then just trigger
+  // the 'readable' event and move on.
+  if (n === 0 && state.needReadable && ((state.highWaterMark !== 0 ? state.length >= state.highWaterMark : state.length > 0) || state.ended)) {
+    debug('read: emitReadable', state.length, state.ended);
+    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
+    return null;
+  }
+  n = howMuchToRead(n, state);
+
+  // if we've ended, and we're now clear, then finish it up.
+  if (n === 0 && state.ended) {
+    if (state.length === 0) endReadable(this);
+    return null;
+  }
+
+  // All the actual chunk generation logic needs to be
+  // *below* the call to _read.  The reason is that in certain
+  // synthetic stream cases, such as passthrough streams, _read
+  // may be a completely synchronous operation which may change
+  // the state of the read buffer, providing enough data when
+  // before there was *not* enough.
+  //
+  // So, the steps are:
+  // 1. Figure out what the state of things will be after we do
+  // a read from the buffer.
+  //
+  // 2. If that resulting state will trigger a _read, then call _read.
+  // Note that this may be asynchronous, or synchronous.  Yes, it is
+  // deeply ugly to write APIs this way, but that still doesn't mean
+  // that the Readable class should behave improperly, as streams are
+  // designed to be sync/async agnostic.
+  // Take note if the _read call is sync or async (ie, if the read call
+  // has returned yet), so that we know whether or not it's safe to emit
+  // 'readable' etc.
+  //
+  // 3. Actually pull the requested chunks out of the buffer and return.
+
+  // if we need a readable event, then we need to do some reading.
+  var doRead = state.needReadable;
+  debug('need readable', doRead);
+
+  // if we currently have less than the highWaterMark, then also read some
+  if (state.length === 0 || state.length - n < state.highWaterMark) {
+    doRead = true;
+    debug('length less than watermark', doRead);
+  }
+
+  // however, if we've ended, then there's no point, and if we're already
+  // reading, then it's unnecessary.
+  if (state.ended || state.reading) {
+    doRead = false;
+    debug('reading or ended', doRead);
+  } else if (doRead) {
+    debug('do read');
+    state.reading = true;
+    state.sync = true;
+    // if the length is currently zero, then we *need* a readable event.
+    if (state.length === 0) state.needReadable = true;
+    // call internal read method
+    this._read(state.highWaterMark);
+    state.sync = false;
+    // If _read pushed data synchronously, then `reading` will be false,
+    // and we need to re-evaluate how much data we can return to the user.
+    if (!state.reading) n = howMuchToRead(nOrig, state);
+  }
+  var ret;
+  if (n > 0) ret = fromList(n, state);else ret = null;
+  if (ret === null) {
+    state.needReadable = state.length <= state.highWaterMark;
+    n = 0;
+  } else {
+    state.length -= n;
+    state.awaitDrain = 0;
+  }
+  if (state.length === 0) {
+    // If we have nothing in the buffer, then we want to know
+    // as soon as we *do* get something into the buffer.
+    if (!state.ended) state.needReadable = true;
+
+    // If we tried to read() past the EOF, then emit end on the next tick.
+    if (nOrig !== n && state.ended) endReadable(this);
+  }
+  if (ret !== null) this.emit('data', ret);
+  return ret;
+};
+function onEofChunk(stream, state) {
+  debug('onEofChunk');
+  if (state.ended) return;
+  if (state.decoder) {
+    var chunk = state.decoder.end();
+    if (chunk && chunk.length) {
+      state.buffer.push(chunk);
+      state.length += state.objectMode ? 1 : chunk.length;
+    }
+  }
+  state.ended = true;
+  if (state.sync) {
+    // if we are sync, wait until next tick to emit the data.
+    // Otherwise we risk emitting data in the flow()
+    // the readable code triggers during a read() call
+    emitReadable(stream);
+  } else {
+    // emit 'readable' now to make sure it gets picked up.
+    state.needReadable = false;
+    if (!state.emittedReadable) {
+      state.emittedReadable = true;
+      emitReadable_(stream);
+    }
+  }
+}
+
+// Don't emit readable right away in sync mode, because this can trigger
+// another read() call => stack overflow.  This way, it might trigger
+// a nextTick recursion warning, but that's not so bad.
+function emitReadable(stream) {
+  var state = stream._readableState;
+  debug('emitReadable', state.needReadable, state.emittedReadable);
+  state.needReadable = false;
+  if (!state.emittedReadable) {
+    debug('emitReadable', state.flowing);
+    state.emittedReadable = true;
+    process.nextTick(emitReadable_, stream);
+  }
+}
+function emitReadable_(stream) {
+  var state = stream._readableState;
+  debug('emitReadable_', state.destroyed, state.length, state.ended);
+  if (!state.destroyed && (state.length || state.ended)) {
+    stream.emit('readable');
+    state.emittedReadable = false;
+  }
+
+  // The stream needs another readable event if
+  // 1. It is not flowing, as the flow mechanism will take
+  //    care of it.
+  // 2. It is not ended.
+  // 3. It is below the highWaterMark, so we can schedule
+  //    another readable later.
+  state.needReadable = !state.flowing && !state.ended && state.length <= state.highWaterMark;
+  flow(stream);
+}
+
+// at this point, the user has presumably seen the 'readable' event,
+// and called read() to consume some data.  that may have triggered
+// in turn another _read(n) call, in which case reading = true if
+// it's in progress.
+// However, if we're not ended, or reading, and the length < hwm,
+// then go ahead and try to read some more preemptively.
+function maybeReadMore(stream, state) {
+  if (!state.readingMore) {
+    state.readingMore = true;
+    process.nextTick(maybeReadMore_, stream, state);
+  }
+}
+function maybeReadMore_(stream, state) {
+  // Attempt to read more data if we should.
+  //
+  // The conditions for reading more data are (one of):
+  // - Not enough data buffered (state.length < state.highWaterMark). The loop
+  //   is responsible for filling the buffer with enough data if such data
+  //   is available. If highWaterMark is 0 and we are not in the flowing mode
+  //   we should _not_ attempt to buffer any extra data. We'll get more data
+  //   when the stream consumer calls read() instead.
+  // - No data in the buffer, and the stream is in flowing mode. In this mode
+  //   the loop below is responsible for ensuring read() is called. Failing to
+  //   call read here would abort the flow and there's no other mechanism for
+  //   continuing the flow if the stream consumer has just subscribed to the
+  //   'data' event.
+  //
+  // In addition to the above conditions to keep reading data, the following
+  // conditions prevent the data from being read:
+  // - The stream has ended (state.ended).
+  // - There is already a pending 'read' operation (state.reading). This is a
+  //   case where the the stream has called the implementation defined _read()
+  //   method, but they are processing the call asynchronously and have _not_
+  //   called push() with new data. In this case we skip performing more
+  //   read()s. The execution ends in this method again after the _read() ends
+  //   up calling push() with more data.
+  while (!state.reading && !state.ended && (state.length < state.highWaterMark || state.flowing && state.length === 0)) {
+    var len = state.length;
+    debug('maybeReadMore read 0');
+    stream.read(0);
+    if (len === state.length)
+      // didn't get any data, stop spinning.
+      break;
+  }
+  state.readingMore = false;
+}
+
+// abstract method.  to be overridden in specific implementation classes.
+// call cb(er, data) where data is <= n in length.
+// for virtual (non-string, non-buffer) streams, "length" is somewhat
+// arbitrary, and perhaps not very meaningful.
+Readable.prototype._read = function (n) {
+  errorOrDestroy(this, new ERR_METHOD_NOT_IMPLEMENTED('_read()'));
+};
+Readable.prototype.pipe = function (dest, pipeOpts) {
+  var src = this;
+  var state = this._readableState;
+  switch (state.pipesCount) {
+    case 0:
+      state.pipes = dest;
+      break;
+    case 1:
+      state.pipes = [state.pipes, dest];
+      break;
+    default:
+      state.pipes.push(dest);
+      break;
+  }
+  state.pipesCount += 1;
+  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
+  var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;
+  var endFn = doEnd ? onend : unpipe;
+  if (state.endEmitted) process.nextTick(endFn);else src.once('end', endFn);
+  dest.on('unpipe', onunpipe);
+  function onunpipe(readable, unpipeInfo) {
+    debug('onunpipe');
+    if (readable === src) {
+      if (unpipeInfo && unpipeInfo.hasUnpiped === false) {
+        unpipeInfo.hasUnpiped = true;
+        cleanup();
+      }
+    }
+  }
+  function onend() {
+    debug('onend');
+    dest.end();
+  }
+
+  // when the dest drains, it reduces the awaitDrain counter
+  // on the source.  This would be more elegant with a .once()
+  // handler in flow(), but adding and removing repeatedly is
+  // too slow.
+  var ondrain = pipeOnDrain(src);
+  dest.on('drain', ondrain);
+  var cleanedUp = false;
+  function cleanup() {
+    debug('cleanup');
+    // cleanup event handlers once the pipe is broken
+    dest.removeListener('close', onclose);
+    dest.removeListener('finish', onfinish);
+    dest.removeListener('drain', ondrain);
+    dest.removeListener('error', onerror);
+    dest.removeListener('unpipe', onunpipe);
+    src.removeListener('end', onend);
+    src.removeListener('end', unpipe);
+    src.removeListener('data', ondata);
+    cleanedUp = true;
+
+    // if the reader is waiting for a drain event from this
+    // specific writer, then it would cause it to never start
+    // flowing again.
+    // So, if this is awaiting a drain, then we just call it now.
+    // If we don't know, then assume that we are waiting for one.
+    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
+  }
+  src.on('data', ondata);
+  function ondata(chunk) {
+    debug('ondata');
+    var ret = dest.write(chunk);
+    debug('dest.write', ret);
+    if (ret === false) {
+      // If the user unpiped during `dest.write()`, it is possible
+      // to get stuck in a permanently paused state if that write
+      // also returned false.
+      // => Check whether `dest` is still a piping destination.
+      if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
+        debug('false write response, pause', state.awaitDrain);
+        state.awaitDrain++;
+      }
+      src.pause();
+    }
+  }
+
+  // if the dest has an error, then stop piping into it.
+  // however, don't suppress the throwing behavior for this.
+  function onerror(er) {
+    debug('onerror', er);
+    unpipe();
+    dest.removeListener('error', onerror);
+    if (EElistenerCount(dest, 'error') === 0) errorOrDestroy(dest, er);
+  }
+
+  // Make sure our error handler is attached before userland ones.
+  prependListener(dest, 'error', onerror);
+
+  // Both close and finish should trigger unpipe, but only once.
+  function onclose() {
+    dest.removeListener('finish', onfinish);
+    unpipe();
+  }
+  dest.once('close', onclose);
+  function onfinish() {
+    debug('onfinish');
+    dest.removeListener('close', onclose);
+    unpipe();
+  }
+  dest.once('finish', onfinish);
+  function unpipe() {
+    debug('unpipe');
+    src.unpipe(dest);
+  }
+
+  // tell the dest that it's being piped to
+  dest.emit('pipe', src);
+
+  // start the flow if it hasn't been started already.
+  if (!state.flowing) {
+    debug('pipe resume');
+    src.resume();
+  }
+  return dest;
+};
+function pipeOnDrain(src) {
+  return function pipeOnDrainFunctionResult() {
+    var state = src._readableState;
+    debug('pipeOnDrain', state.awaitDrain);
+    if (state.awaitDrain) state.awaitDrain--;
+    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
+      state.flowing = true;
+      flow(src);
+    }
+  };
+}
+Readable.prototype.unpipe = function (dest) {
+  var state = this._readableState;
+  var unpipeInfo = {
+    hasUnpiped: false
+  };
+
+  // if we're not piping anywhere, then do nothing.
+  if (state.pipesCount === 0) return this;
+
+  // just one destination.  most common case.
+  if (state.pipesCount === 1) {
+    // passed in one, but it's not the right one.
+    if (dest && dest !== state.pipes) return this;
+    if (!dest) dest = state.pipes;
+
+    // got a match.
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    if (dest) dest.emit('unpipe', this, unpipeInfo);
+    return this;
+  }
+
+  // slow case. multiple pipe destinations.
+
+  if (!dest) {
+    // remove all.
+    var dests = state.pipes;
+    var len = state.pipesCount;
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    for (var i = 0; i < len; i++) dests[i].emit('unpipe', this, {
+      hasUnpiped: false
+    });
+    return this;
+  }
+
+  // try to find the right one.
+  var index = indexOf(state.pipes, dest);
+  if (index === -1) return this;
+  state.pipes.splice(index, 1);
+  state.pipesCount -= 1;
+  if (state.pipesCount === 1) state.pipes = state.pipes[0];
+  dest.emit('unpipe', this, unpipeInfo);
+  return this;
+};
+
+// set up data events if they are asked for
+// Ensure readable listeners eventually get something
+Readable.prototype.on = function (ev, fn) {
+  var res = Stream.prototype.on.call(this, ev, fn);
+  var state = this._readableState;
+  if (ev === 'data') {
+    // update readableListening so that resume() may be a no-op
+    // a few lines down. This is needed to support once('readable').
+    state.readableListening = this.listenerCount('readable') > 0;
+
+    // Try start flowing on next tick if stream isn't explicitly paused
+    if (state.flowing !== false) this.resume();
+  } else if (ev === 'readable') {
+    if (!state.endEmitted && !state.readableListening) {
+      state.readableListening = state.needReadable = true;
+      state.flowing = false;
+      state.emittedReadable = false;
+      debug('on readable', state.length, state.reading);
+      if (state.length) {
+        emitReadable(this);
+      } else if (!state.reading) {
+        process.nextTick(nReadingNextTick, this);
+      }
+    }
+  }
+  return res;
+};
+Readable.prototype.addListener = Readable.prototype.on;
+Readable.prototype.removeListener = function (ev, fn) {
+  var res = Stream.prototype.removeListener.call(this, ev, fn);
+  if (ev === 'readable') {
+    // We need to check if there is someone still listening to
+    // readable and reset the state. However this needs to happen
+    // after readable has been emitted but before I/O (nextTick) to
+    // support once('readable', fn) cycles. This means that calling
+    // resume within the same tick will have no
+    // effect.
+    process.nextTick(updateReadableListening, this);
+  }
+  return res;
+};
+Readable.prototype.removeAllListeners = function (ev) {
+  var res = Stream.prototype.removeAllListeners.apply(this, arguments);
+  if (ev === 'readable' || ev === undefined) {
+    // We need to check if there is someone still listening to
+    // readable and reset the state. However this needs to happen
+    // after readable has been emitted but before I/O (nextTick) to
+    // support once('readable', fn) cycles. This means that calling
+    // resume within the same tick will have no
+    // effect.
+    process.nextTick(updateReadableListening, this);
+  }
+  return res;
+};
+function updateReadableListening(self) {
+  var state = self._readableState;
+  state.readableListening = self.listenerCount('readable') > 0;
+  if (state.resumeScheduled && !state.paused) {
+    // flowing needs to be set to true now, otherwise
+    // the upcoming resume will not flow.
+    state.flowing = true;
+
+    // crude way to check if we should resume
+  } else if (self.listenerCount('data') > 0) {
+    self.resume();
+  }
+}
+function nReadingNextTick(self) {
+  debug('readable nexttick read 0');
+  self.read(0);
+}
+
+// pause() and resume() are remnants of the legacy readable stream API
+// If the user uses them, then switch into old mode.
+Readable.prototype.resume = function () {
+  var state = this._readableState;
+  if (!state.flowing) {
+    debug('resume');
+    // we flow only if there is no one listening
+    // for readable, but we still have to call
+    // resume()
+    state.flowing = !state.readableListening;
+    resume(this, state);
+  }
+  state.paused = false;
+  return this;
+};
+function resume(stream, state) {
+  if (!state.resumeScheduled) {
+    state.resumeScheduled = true;
+    process.nextTick(resume_, stream, state);
+  }
+}
+function resume_(stream, state) {
+  debug('resume', state.reading);
+  if (!state.reading) {
+    stream.read(0);
+  }
+  state.resumeScheduled = false;
+  stream.emit('resume');
+  flow(stream);
+  if (state.flowing && !state.reading) stream.read(0);
+}
+Readable.prototype.pause = function () {
+  debug('call pause flowing=%j', this._readableState.flowing);
+  if (this._readableState.flowing !== false) {
+    debug('pause');
+    this._readableState.flowing = false;
+    this.emit('pause');
+  }
+  this._readableState.paused = true;
+  return this;
+};
+function flow(stream) {
+  var state = stream._readableState;
+  debug('flow', state.flowing);
+  while (state.flowing && stream.read() !== null);
+}
+
+// wrap an old-style stream as the async data source.
+// This is *not* part of the readable stream interface.
+// It is an ugly unfortunate mess of history.
+Readable.prototype.wrap = function (stream) {
+  var _this = this;
+  var state = this._readableState;
+  var paused = false;
+  stream.on('end', function () {
+    debug('wrapped end');
+    if (state.decoder && !state.ended) {
+      var chunk = state.decoder.end();
+      if (chunk && chunk.length) _this.push(chunk);
+    }
+    _this.push(null);
+  });
+  stream.on('data', function (chunk) {
+    debug('wrapped data');
+    if (state.decoder) chunk = state.decoder.write(chunk);
+
+    // don't skip over falsy values in objectMode
+    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;
+    var ret = _this.push(chunk);
+    if (!ret) {
+      paused = true;
+      stream.pause();
+    }
+  });
+
+  // proxy all the other methods.
+  // important when wrapping filters and duplexes.
+  for (var i in stream) {
+    if (this[i] === undefined && typeof stream[i] === 'function') {
+      this[i] = function methodWrap(method) {
+        return function methodWrapReturnFunction() {
+          return stream[method].apply(stream, arguments);
+        };
+      }(i);
+    }
+  }
+
+  // proxy certain important events.
+  for (var n = 0; n < kProxyEvents.length; n++) {
+    stream.on(kProxyEvents[n], this.emit.bind(this, kProxyEvents[n]));
+  }
+
+  // when we try to consume some more bytes, simply unpause the
+  // underlying stream.
+  this._read = function (n) {
+    debug('wrapped _read', n);
+    if (paused) {
+      paused = false;
+      stream.resume();
+    }
+  };
+  return this;
+};
+if (typeof Symbol === 'function') {
+  Readable.prototype[Symbol.asyncIterator] = function () {
+    if (createReadableStreamAsyncIterator === undefined) {
+      createReadableStreamAsyncIterator = require('./internal/streams/async_iterator');
+    }
+    return createReadableStreamAsyncIterator(this);
+  };
+}
+Object.defineProperty(Readable.prototype, 'readableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.highWaterMark;
+  }
+});
+Object.defineProperty(Readable.prototype, 'readableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState && this._readableState.buffer;
+  }
+});
+Object.defineProperty(Readable.prototype, 'readableFlowing', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.flowing;
+  },
+  set: function set(state) {
+    if (this._readableState) {
+      this._readableState.flowing = state;
+    }
+  }
+});
+
+// exposed for testing purposes only.
+Readable._fromList = fromList;
+Object.defineProperty(Readable.prototype, 'readableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.length;
+  }
+});
+
+// Pluck off n bytes from an array of buffers.
+// Length is the combined lengths of all the buffers in the list.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+function fromList(n, state) {
+  // nothing buffered
+  if (state.length === 0) return null;
+  var ret;
+  if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
+    // read it all, truncate the list
+    if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.first();else ret = state.buffer.concat(state.length);
+    state.buffer.clear();
+  } else {
+    // read part of list
+    ret = state.buffer.consume(n, state.decoder);
+  }
+  return ret;
+}
+function endReadable(stream) {
+  var state = stream._readableState;
+  debug('endReadable', state.endEmitted);
+  if (!state.endEmitted) {
+    state.ended = true;
+    process.nextTick(endReadableNT, state, stream);
+  }
+}
+function endReadableNT(state, stream) {
+  debug('endReadableNT', state.endEmitted, state.length);
+
+  // Check that we didn't get one last unshift.
+  if (!state.endEmitted && state.length === 0) {
+    state.endEmitted = true;
+    stream.readable = false;
+    stream.emit('end');
+    if (state.autoDestroy) {
+      // In case of duplex streams we need a way to detect
+      // if the writable side is ready for autoDestroy as well
+      var wState = stream._writableState;
+      if (!wState || wState.autoDestroy && wState.finished) {
+        stream.destroy();
+      }
+    }
+  }
+}
+if (typeof Symbol === 'function') {
+  Readable.from = function (iterable, opts) {
+    if (from === undefined) {
+      from = require('./internal/streams/from');
+    }
+    return from(Readable, iterable, opts);
+  };
+}
+function indexOf(xs, x) {
+  for (var i = 0, l = xs.length; i < l; i++) {
+    if (xs[i] === x) return i;
+  }
+  return -1;
+}
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_transform.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_transform.js
new file mode 100644
index 0000000..1ccb715
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_transform.js
@@ -0,0 +1,190 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// a transform stream is a readable/writable stream where you do
+// something with the data.  Sometimes it's called a "filter",
+// but that's not a great name for it, since that implies a thing where
+// some bits pass through, and others are simply ignored.  (That would
+// be a valid example of a transform, of course.)
+//
+// While the output is causally related to the input, it's not a
+// necessarily symmetric or synchronous transformation.  For example,
+// a zlib stream might take multiple plain-text writes(), and then
+// emit a single compressed chunk some time in the future.
+//
+// Here's how this works:
+//
+// The Transform stream has all the aspects of the readable and writable
+// stream classes.  When you write(chunk), that calls _write(chunk,cb)
+// internally, and returns false if there's a lot of pending writes
+// buffered up.  When you call read(), that calls _read(n) until
+// there's enough pending readable data buffered up.
+//
+// In a transform stream, the written data is placed in a buffer.  When
+// _read(n) is called, it transforms the queued up data, calling the
+// buffered _write cb's as it consumes chunks.  If consuming a single
+// written chunk would result in multiple output chunks, then the first
+// outputted bit calls the readcb, and subsequent chunks just go into
+// the read buffer, and will cause it to emit 'readable' if necessary.
+//
+// This way, back-pressure is actually determined by the reading side,
+// since _read has to be called to start processing a new chunk.  However,
+// a pathological inflate type of transform can cause excessive buffering
+// here.  For example, imagine a stream where every byte of input is
+// interpreted as an integer from 0-255, and then results in that many
+// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
+// 1kb of data being output.  In this case, you could write a very small
+// amount of input, and end up with a very large amount of output.  In
+// such a pathological inflating mechanism, there'd be no way to tell
+// the system to stop doing the transform.  A single 4MB write could
+// cause the system to run out of memory.
+//
+// However, even in such a pathological case, only a single written chunk
+// would be consumed, and then the rest would wait (un-transformed) until
+// the results of the previous transformed chunk were consumed.
+
+'use strict';
+
+module.exports = Transform;
+var _require$codes = require('../errors').codes,
+  ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
+  ERR_TRANSFORM_ALREADY_TRANSFORMING = _require$codes.ERR_TRANSFORM_ALREADY_TRANSFORMING,
+  ERR_TRANSFORM_WITH_LENGTH_0 = _require$codes.ERR_TRANSFORM_WITH_LENGTH_0;
+var Duplex = require('./_stream_duplex');
+require('inherits')(Transform, Duplex);
+function afterTransform(er, data) {
+  var ts = this._transformState;
+  ts.transforming = false;
+  var cb = ts.writecb;
+  if (cb === null) {
+    return this.emit('error', new ERR_MULTIPLE_CALLBACK());
+  }
+  ts.writechunk = null;
+  ts.writecb = null;
+  if (data != null)
+    // single equals check for both `null` and `undefined`
+    this.push(data);
+  cb(er);
+  var rs = this._readableState;
+  rs.reading = false;
+  if (rs.needReadable || rs.length < rs.highWaterMark) {
+    this._read(rs.highWaterMark);
+  }
+}
+function Transform(options) {
+  if (!(this instanceof Transform)) return new Transform(options);
+  Duplex.call(this, options);
+  this._transformState = {
+    afterTransform: afterTransform.bind(this),
+    needTransform: false,
+    transforming: false,
+    writecb: null,
+    writechunk: null,
+    writeencoding: null
+  };
+
+  // start out asking for a readable event once data is transformed.
+  this._readableState.needReadable = true;
+
+  // we have implemented the _read method, and done the other things
+  // that Readable wants before the first _read call, so unset the
+  // sync guard flag.
+  this._readableState.sync = false;
+  if (options) {
+    if (typeof options.transform === 'function') this._transform = options.transform;
+    if (typeof options.flush === 'function') this._flush = options.flush;
+  }
+
+  // When the writable side finishes, then flush out anything remaining.
+  this.on('prefinish', prefinish);
+}
+function prefinish() {
+  var _this = this;
+  if (typeof this._flush === 'function' && !this._readableState.destroyed) {
+    this._flush(function (er, data) {
+      done(_this, er, data);
+    });
+  } else {
+    done(this, null, null);
+  }
+}
+Transform.prototype.push = function (chunk, encoding) {
+  this._transformState.needTransform = false;
+  return Duplex.prototype.push.call(this, chunk, encoding);
+};
+
+// This is the part where you do stuff!
+// override this function in implementation classes.
+// 'chunk' is an input chunk.
+//
+// Call `push(newChunk)` to pass along transformed output
+// to the readable side.  You may call 'push' zero or more times.
+//
+// Call `cb(err)` when you are done with this chunk.  If you pass
+// an error, then that'll put the hurt on the whole operation.  If you
+// never call cb(), then you'll never get another chunk.
+Transform.prototype._transform = function (chunk, encoding, cb) {
+  cb(new ERR_METHOD_NOT_IMPLEMENTED('_transform()'));
+};
+Transform.prototype._write = function (chunk, encoding, cb) {
+  var ts = this._transformState;
+  ts.writecb = cb;
+  ts.writechunk = chunk;
+  ts.writeencoding = encoding;
+  if (!ts.transforming) {
+    var rs = this._readableState;
+    if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
+  }
+};
+
+// Doesn't matter what the args are here.
+// _transform does all the work.
+// That we got here means that the readable side wants more data.
+Transform.prototype._read = function (n) {
+  var ts = this._transformState;
+  if (ts.writechunk !== null && !ts.transforming) {
+    ts.transforming = true;
+    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
+  } else {
+    // mark that we need a transform, so that any data that comes in
+    // will get processed, now that we've asked for it.
+    ts.needTransform = true;
+  }
+};
+Transform.prototype._destroy = function (err, cb) {
+  Duplex.prototype._destroy.call(this, err, function (err2) {
+    cb(err2);
+  });
+};
+function done(stream, er, data) {
+  if (er) return stream.emit('error', er);
+  if (data != null)
+    // single equals check for both `null` and `undefined`
+    stream.push(data);
+
+  // TODO(BridgeAR): Write a test for these two error cases
+  // if there's nothing in the write buffer, then that means
+  // that nothing more will ever be provided
+  if (stream._writableState.length) throw new ERR_TRANSFORM_WITH_LENGTH_0();
+  if (stream._transformState.transforming) throw new ERR_TRANSFORM_ALREADY_TRANSFORMING();
+  return stream.push(null);
+}
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_writable.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_writable.js
new file mode 100644
index 0000000..292415e
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/_stream_writable.js
@@ -0,0 +1,641 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// A bit simpler than readable streams.
+// Implement an async ._write(chunk, encoding, cb), and it'll handle all
+// the drain event emission and buffering.
+
+'use strict';
+
+module.exports = Writable;
+
+/* <replacement> */
+function WriteReq(chunk, encoding, cb) {
+  this.chunk = chunk;
+  this.encoding = encoding;
+  this.callback = cb;
+  this.next = null;
+}
+
+// It seems a linked list but it is not
+// there will be only 2 of these for each stream
+function CorkedRequest(state) {
+  var _this = this;
+  this.next = null;
+  this.entry = null;
+  this.finish = function () {
+    onCorkedFinish(_this, state);
+  };
+}
+/* </replacement> */
+
+/*<replacement>*/
+var Duplex;
+/*</replacement>*/
+
+Writable.WritableState = WritableState;
+
+/*<replacement>*/
+var internalUtil = {
+  deprecate: require('util-deprecate')
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+var Buffer = require('buffer').Buffer;
+var OurUint8Array = (typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : typeof self !== 'undefined' ? self : {}).Uint8Array || function () {};
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+var destroyImpl = require('./internal/streams/destroy');
+var _require = require('./internal/streams/state'),
+  getHighWaterMark = _require.getHighWaterMark;
+var _require$codes = require('../errors').codes,
+  ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
+  ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+  ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
+  ERR_STREAM_CANNOT_PIPE = _require$codes.ERR_STREAM_CANNOT_PIPE,
+  ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED,
+  ERR_STREAM_NULL_VALUES = _require$codes.ERR_STREAM_NULL_VALUES,
+  ERR_STREAM_WRITE_AFTER_END = _require$codes.ERR_STREAM_WRITE_AFTER_END,
+  ERR_UNKNOWN_ENCODING = _require$codes.ERR_UNKNOWN_ENCODING;
+var errorOrDestroy = destroyImpl.errorOrDestroy;
+require('inherits')(Writable, Stream);
+function nop() {}
+function WritableState(options, stream, isDuplex) {
+  Duplex = Duplex || require('./_stream_duplex');
+  options = options || {};
+
+  // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream,
+  // e.g. options.readableObjectMode vs. options.writableObjectMode, etc.
+  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex;
+
+  // object stream flag to indicate whether or not this stream
+  // contains buffers or objects.
+  this.objectMode = !!options.objectMode;
+  if (isDuplex) this.objectMode = this.objectMode || !!options.writableObjectMode;
+
+  // the point at which write() starts returning false
+  // Note: 0 is a valid value, means that we always return false if
+  // the entire buffer is not flushed immediately on write()
+  this.highWaterMark = getHighWaterMark(this, options, 'writableHighWaterMark', isDuplex);
+
+  // if _final has been called
+  this.finalCalled = false;
+
+  // drain event flag.
+  this.needDrain = false;
+  // at the start of calling end()
+  this.ending = false;
+  // when end() has been called, and returned
+  this.ended = false;
+  // when 'finish' is emitted
+  this.finished = false;
+
+  // has it been destroyed
+  this.destroyed = false;
+
+  // should we decode strings into buffers before passing to _write?
+  // this is here so that some node-core streams can optimize string
+  // handling at a lower level.
+  var noDecode = options.decodeStrings === false;
+  this.decodeStrings = !noDecode;
+
+  // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+  this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+  // not an actual buffer we keep track of, but a measurement
+  // of how much we're waiting to get pushed to some underlying
+  // socket or file.
+  this.length = 0;
+
+  // a flag to see when we're in the middle of a write.
+  this.writing = false;
+
+  // when true all writes will be buffered until .uncork() call
+  this.corked = 0;
+
+  // a flag to be able to tell if the onwrite cb is called immediately,
+  // or on a later tick.  We set this to true at first, because any
+  // actions that shouldn't happen until "later" should generally also
+  // not happen before the first write call.
+  this.sync = true;
+
+  // a flag to know if we're processing previously buffered items, which
+  // may call the _write() callback in the same tick, so that we don't
+  // end up in an overlapped onwrite situation.
+  this.bufferProcessing = false;
+
+  // the callback that's passed to _write(chunk,cb)
+  this.onwrite = function (er) {
+    onwrite(stream, er);
+  };
+
+  // the callback that the user supplies to write(chunk,encoding,cb)
+  this.writecb = null;
+
+  // the amount that is being written when _write is called.
+  this.writelen = 0;
+  this.bufferedRequest = null;
+  this.lastBufferedRequest = null;
+
+  // number of pending user-supplied write callbacks
+  // this must be 0 before 'finish' can be emitted
+  this.pendingcb = 0;
+
+  // emit prefinish if the only thing we're waiting for is _write cbs
+  // This is relevant for synchronous Transform streams
+  this.prefinished = false;
+
+  // True if the error was already emitted and should not be thrown again
+  this.errorEmitted = false;
+
+  // Should close be emitted on destroy. Defaults to true.
+  this.emitClose = options.emitClose !== false;
+
+  // Should .destroy() be called after 'finish' (and potentially 'end')
+  this.autoDestroy = !!options.autoDestroy;
+
+  // count buffered requests
+  this.bufferedRequestCount = 0;
+
+  // allocate the first CorkedRequest, there is always
+  // one allocated and free to use, and we maintain at most two
+  this.corkedRequestsFree = new CorkedRequest(this);
+}
+WritableState.prototype.getBuffer = function getBuffer() {
+  var current = this.bufferedRequest;
+  var out = [];
+  while (current) {
+    out.push(current);
+    current = current.next;
+  }
+  return out;
+};
+(function () {
+  try {
+    Object.defineProperty(WritableState.prototype, 'buffer', {
+      get: internalUtil.deprecate(function writableStateBufferGetter() {
+        return this.getBuffer();
+      }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.', 'DEP0003')
+    });
+  } catch (_) {}
+})();
+
+// Test _writableState for inheritance to account for Duplex streams,
+// whose prototype chain only points to Readable.
+var realHasInstance;
+if (typeof Symbol === 'function' && Symbol.hasInstance && typeof Function.prototype[Symbol.hasInstance] === 'function') {
+  realHasInstance = Function.prototype[Symbol.hasInstance];
+  Object.defineProperty(Writable, Symbol.hasInstance, {
+    value: function value(object) {
+      if (realHasInstance.call(this, object)) return true;
+      if (this !== Writable) return false;
+      return object && object._writableState instanceof WritableState;
+    }
+  });
+} else {
+  realHasInstance = function realHasInstance(object) {
+    return object instanceof this;
+  };
+}
+function Writable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+
+  // Writable ctor is applied to Duplexes, too.
+  // `realHasInstance` is necessary because using plain `instanceof`
+  // would return false, as no `_writableState` property is attached.
+
+  // Trying to use the custom `instanceof` for Writable here will also break the
+  // Node.js LazyTransform implementation, which has a non-trivial getter for
+  // `_writableState` that would lead to infinite recursion.
+
+  // Checking for a Stream.Duplex instance is faster here instead of inside
+  // the WritableState constructor, at least with V8 6.5
+  var isDuplex = this instanceof Duplex;
+  if (!isDuplex && !realHasInstance.call(Writable, this)) return new Writable(options);
+  this._writableState = new WritableState(options, this, isDuplex);
+
+  // legacy.
+  this.writable = true;
+  if (options) {
+    if (typeof options.write === 'function') this._write = options.write;
+    if (typeof options.writev === 'function') this._writev = options.writev;
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+    if (typeof options.final === 'function') this._final = options.final;
+  }
+  Stream.call(this);
+}
+
+// Otherwise people can pipe Writable streams, which is just wrong.
+Writable.prototype.pipe = function () {
+  errorOrDestroy(this, new ERR_STREAM_CANNOT_PIPE());
+};
+function writeAfterEnd(stream, cb) {
+  var er = new ERR_STREAM_WRITE_AFTER_END();
+  // TODO: defer error events consistently everywhere, not just the cb
+  errorOrDestroy(stream, er);
+  process.nextTick(cb, er);
+}
+
+// Checks that a user-supplied chunk is valid, especially for the particular
+// mode the stream is in. Currently this means that `null` is never accepted
+// and undefined/non-string values are only allowed in object mode.
+function validChunk(stream, state, chunk, cb) {
+  var er;
+  if (chunk === null) {
+    er = new ERR_STREAM_NULL_VALUES();
+  } else if (typeof chunk !== 'string' && !state.objectMode) {
+    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
+  }
+  if (er) {
+    errorOrDestroy(stream, er);
+    process.nextTick(cb, er);
+    return false;
+  }
+  return true;
+}
+Writable.prototype.write = function (chunk, encoding, cb) {
+  var state = this._writableState;
+  var ret = false;
+  var isBuf = !state.objectMode && _isUint8Array(chunk);
+  if (isBuf && !Buffer.isBuffer(chunk)) {
+    chunk = _uint8ArrayToBuffer(chunk);
+  }
+  if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+  if (isBuf) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;
+  if (typeof cb !== 'function') cb = nop;
+  if (state.ending) writeAfterEnd(this, cb);else if (isBuf || validChunk(this, state, chunk, cb)) {
+    state.pendingcb++;
+    ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
+  }
+  return ret;
+};
+Writable.prototype.cork = function () {
+  this._writableState.corked++;
+};
+Writable.prototype.uncork = function () {
+  var state = this._writableState;
+  if (state.corked) {
+    state.corked--;
+    if (!state.writing && !state.corked && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
+  }
+};
+Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
+  // node::ParseEncoding() requires lower case.
+  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
+  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new ERR_UNKNOWN_ENCODING(encoding);
+  this._writableState.defaultEncoding = encoding;
+  return this;
+};
+Object.defineProperty(Writable.prototype, 'writableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState && this._writableState.getBuffer();
+  }
+});
+function decodeChunk(state, chunk, encoding) {
+  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
+    chunk = Buffer.from(chunk, encoding);
+  }
+  return chunk;
+}
+Object.defineProperty(Writable.prototype, 'writableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.highWaterMark;
+  }
+});
+
+// if we're already writing something, then just put this
+// in the queue, and wait our turn.  Otherwise, call _write
+// If we return false, then we need a drain event, so set that flag.
+function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
+  if (!isBuf) {
+    var newChunk = decodeChunk(state, chunk, encoding);
+    if (chunk !== newChunk) {
+      isBuf = true;
+      encoding = 'buffer';
+      chunk = newChunk;
+    }
+  }
+  var len = state.objectMode ? 1 : chunk.length;
+  state.length += len;
+  var ret = state.length < state.highWaterMark;
+  // we must ensure that previous needDrain will not be reset to false.
+  if (!ret) state.needDrain = true;
+  if (state.writing || state.corked) {
+    var last = state.lastBufferedRequest;
+    state.lastBufferedRequest = {
+      chunk: chunk,
+      encoding: encoding,
+      isBuf: isBuf,
+      callback: cb,
+      next: null
+    };
+    if (last) {
+      last.next = state.lastBufferedRequest;
+    } else {
+      state.bufferedRequest = state.lastBufferedRequest;
+    }
+    state.bufferedRequestCount += 1;
+  } else {
+    doWrite(stream, state, false, len, chunk, encoding, cb);
+  }
+  return ret;
+}
+function doWrite(stream, state, writev, len, chunk, encoding, cb) {
+  state.writelen = len;
+  state.writecb = cb;
+  state.writing = true;
+  state.sync = true;
+  if (state.destroyed) state.onwrite(new ERR_STREAM_DESTROYED('write'));else if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
+  state.sync = false;
+}
+function onwriteError(stream, state, sync, er, cb) {
+  --state.pendingcb;
+  if (sync) {
+    // defer the callback if we are being called synchronously
+    // to avoid piling up things on the stack
+    process.nextTick(cb, er);
+    // this can emit finish, and it will always happen
+    // after error
+    process.nextTick(finishMaybe, stream, state);
+    stream._writableState.errorEmitted = true;
+    errorOrDestroy(stream, er);
+  } else {
+    // the caller expect this to happen before if
+    // it is async
+    cb(er);
+    stream._writableState.errorEmitted = true;
+    errorOrDestroy(stream, er);
+    // this can emit finish, but finish must
+    // always follow error
+    finishMaybe(stream, state);
+  }
+}
+function onwriteStateUpdate(state) {
+  state.writing = false;
+  state.writecb = null;
+  state.length -= state.writelen;
+  state.writelen = 0;
+}
+function onwrite(stream, er) {
+  var state = stream._writableState;
+  var sync = state.sync;
+  var cb = state.writecb;
+  if (typeof cb !== 'function') throw new ERR_MULTIPLE_CALLBACK();
+  onwriteStateUpdate(state);
+  if (er) onwriteError(stream, state, sync, er, cb);else {
+    // Check if we're actually ready to finish, but don't emit yet
+    var finished = needFinish(state) || stream.destroyed;
+    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
+      clearBuffer(stream, state);
+    }
+    if (sync) {
+      process.nextTick(afterWrite, stream, state, finished, cb);
+    } else {
+      afterWrite(stream, state, finished, cb);
+    }
+  }
+}
+function afterWrite(stream, state, finished, cb) {
+  if (!finished) onwriteDrain(stream, state);
+  state.pendingcb--;
+  cb();
+  finishMaybe(stream, state);
+}
+
+// Must force callback to be called on nextTick, so that we don't
+// emit 'drain' before the write() consumer gets the 'false' return
+// value, and has a chance to attach a 'drain' listener.
+function onwriteDrain(stream, state) {
+  if (state.length === 0 && state.needDrain) {
+    state.needDrain = false;
+    stream.emit('drain');
+  }
+}
+
+// if there's something in the buffer waiting, then process it
+function clearBuffer(stream, state) {
+  state.bufferProcessing = true;
+  var entry = state.bufferedRequest;
+  if (stream._writev && entry && entry.next) {
+    // Fast case, write everything using _writev()
+    var l = state.bufferedRequestCount;
+    var buffer = new Array(l);
+    var holder = state.corkedRequestsFree;
+    holder.entry = entry;
+    var count = 0;
+    var allBuffers = true;
+    while (entry) {
+      buffer[count] = entry;
+      if (!entry.isBuf) allBuffers = false;
+      entry = entry.next;
+      count += 1;
+    }
+    buffer.allBuffers = allBuffers;
+    doWrite(stream, state, true, state.length, buffer, '', holder.finish);
+
+    // doWrite is almost always async, defer these to save a bit of time
+    // as the hot path ends with doWrite
+    state.pendingcb++;
+    state.lastBufferedRequest = null;
+    if (holder.next) {
+      state.corkedRequestsFree = holder.next;
+      holder.next = null;
+    } else {
+      state.corkedRequestsFree = new CorkedRequest(state);
+    }
+    state.bufferedRequestCount = 0;
+  } else {
+    // Slow case, write chunks one-by-one
+    while (entry) {
+      var chunk = entry.chunk;
+      var encoding = entry.encoding;
+      var cb = entry.callback;
+      var len = state.objectMode ? 1 : chunk.length;
+      doWrite(stream, state, false, len, chunk, encoding, cb);
+      entry = entry.next;
+      state.bufferedRequestCount--;
+      // if we didn't call the onwrite immediately, then
+      // it means that we need to wait until it does.
+      // also, that means that the chunk and cb are currently
+      // being processed, so move the buffer counter past them.
+      if (state.writing) {
+        break;
+      }
+    }
+    if (entry === null) state.lastBufferedRequest = null;
+  }
+  state.bufferedRequest = entry;
+  state.bufferProcessing = false;
+}
+Writable.prototype._write = function (chunk, encoding, cb) {
+  cb(new ERR_METHOD_NOT_IMPLEMENTED('_write()'));
+};
+Writable.prototype._writev = null;
+Writable.prototype.end = function (chunk, encoding, cb) {
+  var state = this._writableState;
+  if (typeof chunk === 'function') {
+    cb = chunk;
+    chunk = null;
+    encoding = null;
+  } else if (typeof encoding === 'function') {
+    cb = encoding;
+    encoding = null;
+  }
+  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding);
+
+  // .end() fully uncorks
+  if (state.corked) {
+    state.corked = 1;
+    this.uncork();
+  }
+
+  // ignore unnecessary end() calls.
+  if (!state.ending) endWritable(this, state, cb);
+  return this;
+};
+Object.defineProperty(Writable.prototype, 'writableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._writableState.length;
+  }
+});
+function needFinish(state) {
+  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
+}
+function callFinal(stream, state) {
+  stream._final(function (err) {
+    state.pendingcb--;
+    if (err) {
+      errorOrDestroy(stream, err);
+    }
+    state.prefinished = true;
+    stream.emit('prefinish');
+    finishMaybe(stream, state);
+  });
+}
+function prefinish(stream, state) {
+  if (!state.prefinished && !state.finalCalled) {
+    if (typeof stream._final === 'function' && !state.destroyed) {
+      state.pendingcb++;
+      state.finalCalled = true;
+      process.nextTick(callFinal, stream, state);
+    } else {
+      state.prefinished = true;
+      stream.emit('prefinish');
+    }
+  }
+}
+function finishMaybe(stream, state) {
+  var need = needFinish(state);
+  if (need) {
+    prefinish(stream, state);
+    if (state.pendingcb === 0) {
+      state.finished = true;
+      stream.emit('finish');
+      if (state.autoDestroy) {
+        // In case of duplex streams we need a way to detect
+        // if the readable side is ready for autoDestroy as well
+        var rState = stream._readableState;
+        if (!rState || rState.autoDestroy && rState.endEmitted) {
+          stream.destroy();
+        }
+      }
+    }
+  }
+  return need;
+}
+function endWritable(stream, state, cb) {
+  state.ending = true;
+  finishMaybe(stream, state);
+  if (cb) {
+    if (state.finished) process.nextTick(cb);else stream.once('finish', cb);
+  }
+  state.ended = true;
+  stream.writable = false;
+}
+function onCorkedFinish(corkReq, state, err) {
+  var entry = corkReq.entry;
+  corkReq.entry = null;
+  while (entry) {
+    var cb = entry.callback;
+    state.pendingcb--;
+    cb(err);
+    entry = entry.next;
+  }
+
+  // reuse the free corkReq.
+  state.corkedRequestsFree.next = corkReq;
+}
+Object.defineProperty(Writable.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._writableState === undefined) {
+      return false;
+    }
+    return this._writableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._writableState) {
+      return;
+    }
+
+    // backward compatibility, the user is explicitly
+    // managing destroyed
+    this._writableState.destroyed = value;
+  }
+});
+Writable.prototype.destroy = destroyImpl.destroy;
+Writable.prototype._undestroy = destroyImpl.undestroy;
+Writable.prototype._destroy = function (err, cb) {
+  cb(err);
+};
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/async_iterator.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/async_iterator.js
new file mode 100644
index 0000000..742c5a4
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/async_iterator.js
@@ -0,0 +1,180 @@
+'use strict';
+
+var _Object$setPrototypeO;
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+var finished = require('./end-of-stream');
+var kLastResolve = Symbol('lastResolve');
+var kLastReject = Symbol('lastReject');
+var kError = Symbol('error');
+var kEnded = Symbol('ended');
+var kLastPromise = Symbol('lastPromise');
+var kHandlePromise = Symbol('handlePromise');
+var kStream = Symbol('stream');
+function createIterResult(value, done) {
+  return {
+    value: value,
+    done: done
+  };
+}
+function readAndResolve(iter) {
+  var resolve = iter[kLastResolve];
+  if (resolve !== null) {
+    var data = iter[kStream].read();
+    // we defer if data is null
+    // we can be expecting either 'end' or
+    // 'error'
+    if (data !== null) {
+      iter[kLastPromise] = null;
+      iter[kLastResolve] = null;
+      iter[kLastReject] = null;
+      resolve(createIterResult(data, false));
+    }
+  }
+}
+function onReadable(iter) {
+  // we wait for the next tick, because it might
+  // emit an error with process.nextTick
+  process.nextTick(readAndResolve, iter);
+}
+function wrapForNext(lastPromise, iter) {
+  return function (resolve, reject) {
+    lastPromise.then(function () {
+      if (iter[kEnded]) {
+        resolve(createIterResult(undefined, true));
+        return;
+      }
+      iter[kHandlePromise](resolve, reject);
+    }, reject);
+  };
+}
+var AsyncIteratorPrototype = Object.getPrototypeOf(function () {});
+var ReadableStreamAsyncIteratorPrototype = Object.setPrototypeOf((_Object$setPrototypeO = {
+  get stream() {
+    return this[kStream];
+  },
+  next: function next() {
+    var _this = this;
+    // if we have detected an error in the meanwhile
+    // reject straight away
+    var error = this[kError];
+    if (error !== null) {
+      return Promise.reject(error);
+    }
+    if (this[kEnded]) {
+      return Promise.resolve(createIterResult(undefined, true));
+    }
+    if (this[kStream].destroyed) {
+      // We need to defer via nextTick because if .destroy(err) is
+      // called, the error will be emitted via nextTick, and
+      // we cannot guarantee that there is no error lingering around
+      // waiting to be emitted.
+      return new Promise(function (resolve, reject) {
+        process.nextTick(function () {
+          if (_this[kError]) {
+            reject(_this[kError]);
+          } else {
+            resolve(createIterResult(undefined, true));
+          }
+        });
+      });
+    }
+
+    // if we have multiple next() calls
+    // we will wait for the previous Promise to finish
+    // this logic is optimized to support for await loops,
+    // where next() is only called once at a time
+    var lastPromise = this[kLastPromise];
+    var promise;
+    if (lastPromise) {
+      promise = new Promise(wrapForNext(lastPromise, this));
+    } else {
+      // fast path needed to support multiple this.push()
+      // without triggering the next() queue
+      var data = this[kStream].read();
+      if (data !== null) {
+        return Promise.resolve(createIterResult(data, false));
+      }
+      promise = new Promise(this[kHandlePromise]);
+    }
+    this[kLastPromise] = promise;
+    return promise;
+  }
+}, _defineProperty(_Object$setPrototypeO, Symbol.asyncIterator, function () {
+  return this;
+}), _defineProperty(_Object$setPrototypeO, "return", function _return() {
+  var _this2 = this;
+  // destroy(err, cb) is a private API
+  // we can guarantee we have that here, because we control the
+  // Readable class this is attached to
+  return new Promise(function (resolve, reject) {
+    _this2[kStream].destroy(null, function (err) {
+      if (err) {
+        reject(err);
+        return;
+      }
+      resolve(createIterResult(undefined, true));
+    });
+  });
+}), _Object$setPrototypeO), AsyncIteratorPrototype);
+var createReadableStreamAsyncIterator = function createReadableStreamAsyncIterator(stream) {
+  var _Object$create;
+  var iterator = Object.create(ReadableStreamAsyncIteratorPrototype, (_Object$create = {}, _defineProperty(_Object$create, kStream, {
+    value: stream,
+    writable: true
+  }), _defineProperty(_Object$create, kLastResolve, {
+    value: null,
+    writable: true
+  }), _defineProperty(_Object$create, kLastReject, {
+    value: null,
+    writable: true
+  }), _defineProperty(_Object$create, kError, {
+    value: null,
+    writable: true
+  }), _defineProperty(_Object$create, kEnded, {
+    value: stream._readableState.endEmitted,
+    writable: true
+  }), _defineProperty(_Object$create, kHandlePromise, {
+    value: function value(resolve, reject) {
+      var data = iterator[kStream].read();
+      if (data) {
+        iterator[kLastPromise] = null;
+        iterator[kLastResolve] = null;
+        iterator[kLastReject] = null;
+        resolve(createIterResult(data, false));
+      } else {
+        iterator[kLastResolve] = resolve;
+        iterator[kLastReject] = reject;
+      }
+    },
+    writable: true
+  }), _Object$create));
+  iterator[kLastPromise] = null;
+  finished(stream, function (err) {
+    if (err && err.code !== 'ERR_STREAM_PREMATURE_CLOSE') {
+      var reject = iterator[kLastReject];
+      // reject if we are waiting for data in the Promise
+      // returned by next() and store the error
+      if (reject !== null) {
+        iterator[kLastPromise] = null;
+        iterator[kLastResolve] = null;
+        iterator[kLastReject] = null;
+        reject(err);
+      }
+      iterator[kError] = err;
+      return;
+    }
+    var resolve = iterator[kLastResolve];
+    if (resolve !== null) {
+      iterator[kLastPromise] = null;
+      iterator[kLastResolve] = null;
+      iterator[kLastReject] = null;
+      resolve(createIterResult(undefined, true));
+    }
+    iterator[kEnded] = true;
+  });
+  stream.on('readable', onReadable.bind(null, iterator));
+  return iterator;
+};
+module.exports = createReadableStreamAsyncIterator;
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/buffer_list.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/buffer_list.js
new file mode 100644
index 0000000..69bda49
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/buffer_list.js
@@ -0,0 +1,183 @@
+'use strict';
+
+function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); enumerableOnly && (symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; })), keys.push.apply(keys, symbols); } return keys; }
+function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = null != arguments[i] ? arguments[i] : {}; i % 2 ? ownKeys(Object(source), !0).forEach(function (key) { _defineProperty(target, key, source[key]); }) : Object.getOwnPropertyDescriptors ? Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)) : ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } return target; }
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, _toPropertyKey(descriptor.key), descriptor); } }
+function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+var _require = require('buffer'),
+  Buffer = _require.Buffer;
+var _require2 = require('util'),
+  inspect = _require2.inspect;
+var custom = inspect && inspect.custom || 'inspect';
+function copyBuffer(src, target, offset) {
+  Buffer.prototype.copy.call(src, target, offset);
+}
+module.exports = /*#__PURE__*/function () {
+  function BufferList() {
+    _classCallCheck(this, BufferList);
+    this.head = null;
+    this.tail = null;
+    this.length = 0;
+  }
+  _createClass(BufferList, [{
+    key: "push",
+    value: function push(v) {
+      var entry = {
+        data: v,
+        next: null
+      };
+      if (this.length > 0) this.tail.next = entry;else this.head = entry;
+      this.tail = entry;
+      ++this.length;
+    }
+  }, {
+    key: "unshift",
+    value: function unshift(v) {
+      var entry = {
+        data: v,
+        next: this.head
+      };
+      if (this.length === 0) this.tail = entry;
+      this.head = entry;
+      ++this.length;
+    }
+  }, {
+    key: "shift",
+    value: function shift() {
+      if (this.length === 0) return;
+      var ret = this.head.data;
+      if (this.length === 1) this.head = this.tail = null;else this.head = this.head.next;
+      --this.length;
+      return ret;
+    }
+  }, {
+    key: "clear",
+    value: function clear() {
+      this.head = this.tail = null;
+      this.length = 0;
+    }
+  }, {
+    key: "join",
+    value: function join(s) {
+      if (this.length === 0) return '';
+      var p = this.head;
+      var ret = '' + p.data;
+      while (p = p.next) ret += s + p.data;
+      return ret;
+    }
+  }, {
+    key: "concat",
+    value: function concat(n) {
+      if (this.length === 0) return Buffer.alloc(0);
+      var ret = Buffer.allocUnsafe(n >>> 0);
+      var p = this.head;
+      var i = 0;
+      while (p) {
+        copyBuffer(p.data, ret, i);
+        i += p.data.length;
+        p = p.next;
+      }
+      return ret;
+    }
+
+    // Consumes a specified amount of bytes or characters from the buffered data.
+  }, {
+    key: "consume",
+    value: function consume(n, hasStrings) {
+      var ret;
+      if (n < this.head.data.length) {
+        // `slice` is the same for buffers and strings.
+        ret = this.head.data.slice(0, n);
+        this.head.data = this.head.data.slice(n);
+      } else if (n === this.head.data.length) {
+        // First chunk is a perfect match.
+        ret = this.shift();
+      } else {
+        // Result spans more than one buffer.
+        ret = hasStrings ? this._getString(n) : this._getBuffer(n);
+      }
+      return ret;
+    }
+  }, {
+    key: "first",
+    value: function first() {
+      return this.head.data;
+    }
+
+    // Consumes a specified amount of characters from the buffered data.
+  }, {
+    key: "_getString",
+    value: function _getString(n) {
+      var p = this.head;
+      var c = 1;
+      var ret = p.data;
+      n -= ret.length;
+      while (p = p.next) {
+        var str = p.data;
+        var nb = n > str.length ? str.length : n;
+        if (nb === str.length) ret += str;else ret += str.slice(0, n);
+        n -= nb;
+        if (n === 0) {
+          if (nb === str.length) {
+            ++c;
+            if (p.next) this.head = p.next;else this.head = this.tail = null;
+          } else {
+            this.head = p;
+            p.data = str.slice(nb);
+          }
+          break;
+        }
+        ++c;
+      }
+      this.length -= c;
+      return ret;
+    }
+
+    // Consumes a specified amount of bytes from the buffered data.
+  }, {
+    key: "_getBuffer",
+    value: function _getBuffer(n) {
+      var ret = Buffer.allocUnsafe(n);
+      var p = this.head;
+      var c = 1;
+      p.data.copy(ret);
+      n -= p.data.length;
+      while (p = p.next) {
+        var buf = p.data;
+        var nb = n > buf.length ? buf.length : n;
+        buf.copy(ret, ret.length - n, 0, nb);
+        n -= nb;
+        if (n === 0) {
+          if (nb === buf.length) {
+            ++c;
+            if (p.next) this.head = p.next;else this.head = this.tail = null;
+          } else {
+            this.head = p;
+            p.data = buf.slice(nb);
+          }
+          break;
+        }
+        ++c;
+      }
+      this.length -= c;
+      return ret;
+    }
+
+    // Make sure the linked list only shows the minimal necessary information.
+  }, {
+    key: custom,
+    value: function value(_, options) {
+      return inspect(this, _objectSpread(_objectSpread({}, options), {}, {
+        // Only inspect one level.
+        depth: 0,
+        // It should not recurse.
+        customInspect: false
+      }));
+    }
+  }]);
+  return BufferList;
+}();
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/destroy.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/destroy.js
new file mode 100644
index 0000000..31a17c4
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/destroy.js
@@ -0,0 +1,96 @@
+'use strict';
+
+// undocumented cb() API, needed for core, not for public API
+function destroy(err, cb) {
+  var _this = this;
+  var readableDestroyed = this._readableState && this._readableState.destroyed;
+  var writableDestroyed = this._writableState && this._writableState.destroyed;
+  if (readableDestroyed || writableDestroyed) {
+    if (cb) {
+      cb(err);
+    } else if (err) {
+      if (!this._writableState) {
+        process.nextTick(emitErrorNT, this, err);
+      } else if (!this._writableState.errorEmitted) {
+        this._writableState.errorEmitted = true;
+        process.nextTick(emitErrorNT, this, err);
+      }
+    }
+    return this;
+  }
+
+  // we set destroyed to true before firing error callbacks in order
+  // to make it re-entrance safe in case destroy() is called within callbacks
+
+  if (this._readableState) {
+    this._readableState.destroyed = true;
+  }
+
+  // if this is a duplex stream mark the writable part as destroyed as well
+  if (this._writableState) {
+    this._writableState.destroyed = true;
+  }
+  this._destroy(err || null, function (err) {
+    if (!cb && err) {
+      if (!_this._writableState) {
+        process.nextTick(emitErrorAndCloseNT, _this, err);
+      } else if (!_this._writableState.errorEmitted) {
+        _this._writableState.errorEmitted = true;
+        process.nextTick(emitErrorAndCloseNT, _this, err);
+      } else {
+        process.nextTick(emitCloseNT, _this);
+      }
+    } else if (cb) {
+      process.nextTick(emitCloseNT, _this);
+      cb(err);
+    } else {
+      process.nextTick(emitCloseNT, _this);
+    }
+  });
+  return this;
+}
+function emitErrorAndCloseNT(self, err) {
+  emitErrorNT(self, err);
+  emitCloseNT(self);
+}
+function emitCloseNT(self) {
+  if (self._writableState && !self._writableState.emitClose) return;
+  if (self._readableState && !self._readableState.emitClose) return;
+  self.emit('close');
+}
+function undestroy() {
+  if (this._readableState) {
+    this._readableState.destroyed = false;
+    this._readableState.reading = false;
+    this._readableState.ended = false;
+    this._readableState.endEmitted = false;
+  }
+  if (this._writableState) {
+    this._writableState.destroyed = false;
+    this._writableState.ended = false;
+    this._writableState.ending = false;
+    this._writableState.finalCalled = false;
+    this._writableState.prefinished = false;
+    this._writableState.finished = false;
+    this._writableState.errorEmitted = false;
+  }
+}
+function emitErrorNT(self, err) {
+  self.emit('error', err);
+}
+function errorOrDestroy(stream, err) {
+  // We have tests that rely on errors being emitted
+  // in the same tick, so changing this is semver major.
+  // For now when you opt-in to autoDestroy we allow
+  // the error to be emitted nextTick. In a future
+  // semver major update we should change the default to this.
+
+  var rState = stream._readableState;
+  var wState = stream._writableState;
+  if (rState && rState.autoDestroy || wState && wState.autoDestroy) stream.destroy(err);else stream.emit('error', err);
+}
+module.exports = {
+  destroy: destroy,
+  undestroy: undestroy,
+  errorOrDestroy: errorOrDestroy
+};
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/end-of-stream.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/end-of-stream.js
new file mode 100644
index 0000000..59c671b
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/end-of-stream.js
@@ -0,0 +1,86 @@
+// Ported from https://github.com/mafintosh/end-of-stream with
+// permission from the author, Mathias Buus (@mafintosh).
+
+'use strict';
+
+var ERR_STREAM_PREMATURE_CLOSE = require('../../../errors').codes.ERR_STREAM_PREMATURE_CLOSE;
+function once(callback) {
+  var called = false;
+  return function () {
+    if (called) return;
+    called = true;
+    for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
+      args[_key] = arguments[_key];
+    }
+    callback.apply(this, args);
+  };
+}
+function noop() {}
+function isRequest(stream) {
+  return stream.setHeader && typeof stream.abort === 'function';
+}
+function eos(stream, opts, callback) {
+  if (typeof opts === 'function') return eos(stream, null, opts);
+  if (!opts) opts = {};
+  callback = once(callback || noop);
+  var readable = opts.readable || opts.readable !== false && stream.readable;
+  var writable = opts.writable || opts.writable !== false && stream.writable;
+  var onlegacyfinish = function onlegacyfinish() {
+    if (!stream.writable) onfinish();
+  };
+  var writableEnded = stream._writableState && stream._writableState.finished;
+  var onfinish = function onfinish() {
+    writable = false;
+    writableEnded = true;
+    if (!readable) callback.call(stream);
+  };
+  var readableEnded = stream._readableState && stream._readableState.endEmitted;
+  var onend = function onend() {
+    readable = false;
+    readableEnded = true;
+    if (!writable) callback.call(stream);
+  };
+  var onerror = function onerror(err) {
+    callback.call(stream, err);
+  };
+  var onclose = function onclose() {
+    var err;
+    if (readable && !readableEnded) {
+      if (!stream._readableState || !stream._readableState.ended) err = new ERR_STREAM_PREMATURE_CLOSE();
+      return callback.call(stream, err);
+    }
+    if (writable && !writableEnded) {
+      if (!stream._writableState || !stream._writableState.ended) err = new ERR_STREAM_PREMATURE_CLOSE();
+      return callback.call(stream, err);
+    }
+  };
+  var onrequest = function onrequest() {
+    stream.req.on('finish', onfinish);
+  };
+  if (isRequest(stream)) {
+    stream.on('complete', onfinish);
+    stream.on('abort', onclose);
+    if (stream.req) onrequest();else stream.on('request', onrequest);
+  } else if (writable && !stream._writableState) {
+    // legacy streams
+    stream.on('end', onlegacyfinish);
+    stream.on('close', onlegacyfinish);
+  }
+  stream.on('end', onend);
+  stream.on('finish', onfinish);
+  if (opts.error !== false) stream.on('error', onerror);
+  stream.on('close', onclose);
+  return function () {
+    stream.removeListener('complete', onfinish);
+    stream.removeListener('abort', onclose);
+    stream.removeListener('request', onrequest);
+    if (stream.req) stream.req.removeListener('finish', onfinish);
+    stream.removeListener('end', onlegacyfinish);
+    stream.removeListener('close', onlegacyfinish);
+    stream.removeListener('finish', onfinish);
+    stream.removeListener('end', onend);
+    stream.removeListener('error', onerror);
+    stream.removeListener('close', onclose);
+  };
+}
+module.exports = eos;
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/from-browser.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/from-browser.js
new file mode 100644
index 0000000..a4ce56f
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/from-browser.js
@@ -0,0 +1,3 @@
+module.exports = function () {
+  throw new Error('Readable.from is not available in the browser')
+};
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/from.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/from.js
new file mode 100644
index 0000000..0a34ee9
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/from.js
@@ -0,0 +1,52 @@
+'use strict';
+
+function asyncGeneratorStep(gen, resolve, reject, _next, _throw, key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { Promise.resolve(value).then(_next, _throw); } }
+function _asyncToGenerator(fn) { return function () { var self = this, args = arguments; return new Promise(function (resolve, reject) { var gen = fn.apply(self, args); function _next(value) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "next", value); } function _throw(err) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "throw", err); } _next(undefined); }); }; }
+function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); enumerableOnly && (symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; })), keys.push.apply(keys, symbols); } return keys; }
+function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = null != arguments[i] ? arguments[i] : {}; i % 2 ? ownKeys(Object(source), !0).forEach(function (key) { _defineProperty(target, key, source[key]); }) : Object.getOwnPropertyDescriptors ? Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)) : ownKeys(Object(source)).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } return target; }
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+var ERR_INVALID_ARG_TYPE = require('../../../errors').codes.ERR_INVALID_ARG_TYPE;
+function from(Readable, iterable, opts) {
+  var iterator;
+  if (iterable && typeof iterable.next === 'function') {
+    iterator = iterable;
+  } else if (iterable && iterable[Symbol.asyncIterator]) iterator = iterable[Symbol.asyncIterator]();else if (iterable && iterable[Symbol.iterator]) iterator = iterable[Symbol.iterator]();else throw new ERR_INVALID_ARG_TYPE('iterable', ['Iterable'], iterable);
+  var readable = new Readable(_objectSpread({
+    objectMode: true
+  }, opts));
+  // Reading boolean to protect against _read
+  // being called before last iteration completion.
+  var reading = false;
+  readable._read = function () {
+    if (!reading) {
+      reading = true;
+      next();
+    }
+  };
+  function next() {
+    return _next2.apply(this, arguments);
+  }
+  function _next2() {
+    _next2 = _asyncToGenerator(function* () {
+      try {
+        var _yield$iterator$next = yield iterator.next(),
+          value = _yield$iterator$next.value,
+          done = _yield$iterator$next.done;
+        if (done) {
+          readable.push(null);
+        } else if (readable.push(yield value)) {
+          next();
+        } else {
+          reading = false;
+        }
+      } catch (err) {
+        readable.destroy(err);
+      }
+    });
+    return _next2.apply(this, arguments);
+  }
+  return readable;
+}
+module.exports = from;
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/pipeline.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/pipeline.js
new file mode 100644
index 0000000..e6f3924
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/pipeline.js
@@ -0,0 +1,86 @@
+// Ported from https://github.com/mafintosh/pump with
+// permission from the author, Mathias Buus (@mafintosh).
+
+'use strict';
+
+var eos;
+function once(callback) {
+  var called = false;
+  return function () {
+    if (called) return;
+    called = true;
+    callback.apply(void 0, arguments);
+  };
+}
+var _require$codes = require('../../../errors').codes,
+  ERR_MISSING_ARGS = _require$codes.ERR_MISSING_ARGS,
+  ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED;
+function noop(err) {
+  // Rethrow the error if it exists to avoid swallowing it
+  if (err) throw err;
+}
+function isRequest(stream) {
+  return stream.setHeader && typeof stream.abort === 'function';
+}
+function destroyer(stream, reading, writing, callback) {
+  callback = once(callback);
+  var closed = false;
+  stream.on('close', function () {
+    closed = true;
+  });
+  if (eos === undefined) eos = require('./end-of-stream');
+  eos(stream, {
+    readable: reading,
+    writable: writing
+  }, function (err) {
+    if (err) return callback(err);
+    closed = true;
+    callback();
+  });
+  var destroyed = false;
+  return function (err) {
+    if (closed) return;
+    if (destroyed) return;
+    destroyed = true;
+
+    // request.destroy just do .end - .abort is what we want
+    if (isRequest(stream)) return stream.abort();
+    if (typeof stream.destroy === 'function') return stream.destroy();
+    callback(err || new ERR_STREAM_DESTROYED('pipe'));
+  };
+}
+function call(fn) {
+  fn();
+}
+function pipe(from, to) {
+  return from.pipe(to);
+}
+function popCallback(streams) {
+  if (!streams.length) return noop;
+  if (typeof streams[streams.length - 1] !== 'function') return noop;
+  return streams.pop();
+}
+function pipeline() {
+  for (var _len = arguments.length, streams = new Array(_len), _key = 0; _key < _len; _key++) {
+    streams[_key] = arguments[_key];
+  }
+  var callback = popCallback(streams);
+  if (Array.isArray(streams[0])) streams = streams[0];
+  if (streams.length < 2) {
+    throw new ERR_MISSING_ARGS('streams');
+  }
+  var error;
+  var destroys = streams.map(function (stream, i) {
+    var reading = i < streams.length - 1;
+    var writing = i > 0;
+    return destroyer(stream, reading, writing, function (err) {
+      if (!error) error = err;
+      if (err) destroys.forEach(call);
+      if (reading) return;
+      destroys.forEach(call);
+      callback(error);
+    });
+  });
+  return streams.reduce(pipe);
+}
+module.exports = pipeline;
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/state.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/state.js
new file mode 100644
index 0000000..3fbf892
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/state.js
@@ -0,0 +1,22 @@
+'use strict';
+
+var ERR_INVALID_OPT_VALUE = require('../../../errors').codes.ERR_INVALID_OPT_VALUE;
+function highWaterMarkFrom(options, isDuplex, duplexKey) {
+  return options.highWaterMark != null ? options.highWaterMark : isDuplex ? options[duplexKey] : null;
+}
+function getHighWaterMark(state, options, duplexKey, isDuplex) {
+  var hwm = highWaterMarkFrom(options, isDuplex, duplexKey);
+  if (hwm != null) {
+    if (!(isFinite(hwm) && Math.floor(hwm) === hwm) || hwm < 0) {
+      var name = isDuplex ? duplexKey : 'highWaterMark';
+      throw new ERR_INVALID_OPT_VALUE(name, hwm);
+    }
+    return Math.floor(hwm);
+  }
+
+  // Default value
+  return state.objectMode ? 16 : 16 * 1024;
+}
+module.exports = {
+  getHighWaterMark: getHighWaterMark
+};
\ No newline at end of file
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/stream-browser.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/stream-browser.js
new file mode 100644
index 0000000..9332a3f
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/stream-browser.js
@@ -0,0 +1 @@
+module.exports = require('events').EventEmitter;
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/stream.js b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/stream.js
new file mode 100644
index 0000000..ce2ad5b
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/lib/internal/streams/stream.js
@@ -0,0 +1 @@
+module.exports = require('stream');
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/package.json b/server/node_modules/tar-stream/node_modules/readable-stream/package.json
new file mode 100644
index 0000000..ade59e7
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/package.json
@@ -0,0 +1,68 @@
+{
+  "name": "readable-stream",
+  "version": "3.6.2",
+  "description": "Streams3, a user-land copy of the stream library from Node.js",
+  "main": "readable.js",
+  "engines": {
+    "node": ">= 6"
+  },
+  "dependencies": {
+    "inherits": "^2.0.3",
+    "string_decoder": "^1.1.1",
+    "util-deprecate": "^1.0.1"
+  },
+  "devDependencies": {
+    "@babel/cli": "^7.2.0",
+    "@babel/core": "^7.2.0",
+    "@babel/polyfill": "^7.0.0",
+    "@babel/preset-env": "^7.2.0",
+    "airtap": "0.0.9",
+    "assert": "^1.4.0",
+    "bl": "^2.0.0",
+    "deep-strict-equal": "^0.2.0",
+    "events.once": "^2.0.2",
+    "glob": "^7.1.2",
+    "gunzip-maybe": "^1.4.1",
+    "hyperquest": "^2.1.3",
+    "lolex": "^2.6.0",
+    "nyc": "^11.0.0",
+    "pump": "^3.0.0",
+    "rimraf": "^2.6.2",
+    "tap": "^12.0.0",
+    "tape": "^4.9.0",
+    "tar-fs": "^1.16.2",
+    "util-promisify": "^2.1.0"
+  },
+  "scripts": {
+    "test": "tap -J --no-esm test/parallel/*.js test/ours/*.js",
+    "ci": "TAP=1 tap --no-esm test/parallel/*.js test/ours/*.js | tee test.tap",
+    "test-browsers": "airtap --sauce-connect --loopback airtap.local -- test/browser.js",
+    "test-browser-local": "airtap --open --local -- test/browser.js",
+    "cover": "nyc npm test",
+    "report": "nyc report --reporter=lcov",
+    "update-browser-errors": "babel -o errors-browser.js errors.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/nodejs/readable-stream"
+  },
+  "keywords": [
+    "readable",
+    "stream",
+    "pipe"
+  ],
+  "browser": {
+    "util": false,
+    "worker_threads": false,
+    "./errors": "./errors-browser.js",
+    "./readable.js": "./readable-browser.js",
+    "./lib/internal/streams/from.js": "./lib/internal/streams/from-browser.js",
+    "./lib/internal/streams/stream.js": "./lib/internal/streams/stream-browser.js"
+  },
+  "nyc": {
+    "include": [
+      "lib/**.js"
+    ]
+  },
+  "license": "MIT"
+}
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/readable-browser.js b/server/node_modules/tar-stream/node_modules/readable-stream/readable-browser.js
new file mode 100644
index 0000000..adbf60d
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/readable-browser.js
@@ -0,0 +1,9 @@
+exports = module.exports = require('./lib/_stream_readable.js');
+exports.Stream = exports;
+exports.Readable = exports;
+exports.Writable = require('./lib/_stream_writable.js');
+exports.Duplex = require('./lib/_stream_duplex.js');
+exports.Transform = require('./lib/_stream_transform.js');
+exports.PassThrough = require('./lib/_stream_passthrough.js');
+exports.finished = require('./lib/internal/streams/end-of-stream.js');
+exports.pipeline = require('./lib/internal/streams/pipeline.js');
diff --git a/server/node_modules/tar-stream/node_modules/readable-stream/readable.js b/server/node_modules/tar-stream/node_modules/readable-stream/readable.js
new file mode 100644
index 0000000..9e0ca12
--- /dev/null
+++ b/server/node_modules/tar-stream/node_modules/readable-stream/readable.js
@@ -0,0 +1,16 @@
+var Stream = require('stream');
+if (process.env.READABLE_STREAM === 'disable' && Stream) {
+  module.exports = Stream.Readable;
+  Object.assign(module.exports, Stream);
+  module.exports.Stream = Stream;
+} else {
+  exports = module.exports = require('./lib/_stream_readable.js');
+  exports.Stream = Stream || exports;
+  exports.Readable = exports;
+  exports.Writable = require('./lib/_stream_writable.js');
+  exports.Duplex = require('./lib/_stream_duplex.js');
+  exports.Transform = require('./lib/_stream_transform.js');
+  exports.PassThrough = require('./lib/_stream_passthrough.js');
+  exports.finished = require('./lib/internal/streams/end-of-stream.js');
+  exports.pipeline = require('./lib/internal/streams/pipeline.js');
+}
diff --git a/server/node_modules/tar-stream/pack.js b/server/node_modules/tar-stream/pack.js
new file mode 100644
index 0000000..f1da3b7
--- /dev/null
+++ b/server/node_modules/tar-stream/pack.js
@@ -0,0 +1,255 @@
+var constants = require('fs-constants')
+var eos = require('end-of-stream')
+var inherits = require('inherits')
+var alloc = Buffer.alloc
+
+var Readable = require('readable-stream').Readable
+var Writable = require('readable-stream').Writable
+var StringDecoder = require('string_decoder').StringDecoder
+
+var headers = require('./headers')
+
+var DMODE = parseInt('755', 8)
+var FMODE = parseInt('644', 8)
+
+var END_OF_TAR = alloc(1024)
+
+var noop = function () {}
+
+var overflow = function (self, size) {
+  size &= 511
+  if (size) self.push(END_OF_TAR.slice(0, 512 - size))
+}
+
+function modeToType (mode) {
+  switch (mode & constants.S_IFMT) {
+    case constants.S_IFBLK: return 'block-device'
+    case constants.S_IFCHR: return 'character-device'
+    case constants.S_IFDIR: return 'directory'
+    case constants.S_IFIFO: return 'fifo'
+    case constants.S_IFLNK: return 'symlink'
+  }
+
+  return 'file'
+}
+
+var Sink = function (to) {
+  Writable.call(this)
+  this.written = 0
+  this._to = to
+  this._destroyed = false
+}
+
+inherits(Sink, Writable)
+
+Sink.prototype._write = function (data, enc, cb) {
+  this.written += data.length
+  if (this._to.push(data)) return cb()
+  this._to._drain = cb
+}
+
+Sink.prototype.destroy = function () {
+  if (this._destroyed) return
+  this._destroyed = true
+  this.emit('close')
+}
+
+var LinkSink = function () {
+  Writable.call(this)
+  this.linkname = ''
+  this._decoder = new StringDecoder('utf-8')
+  this._destroyed = false
+}
+
+inherits(LinkSink, Writable)
+
+LinkSink.prototype._write = function (data, enc, cb) {
+  this.linkname += this._decoder.write(data)
+  cb()
+}
+
+LinkSink.prototype.destroy = function () {
+  if (this._destroyed) return
+  this._destroyed = true
+  this.emit('close')
+}
+
+var Void = function () {
+  Writable.call(this)
+  this._destroyed = false
+}
+
+inherits(Void, Writable)
+
+Void.prototype._write = function (data, enc, cb) {
+  cb(new Error('No body allowed for this entry'))
+}
+
+Void.prototype.destroy = function () {
+  if (this._destroyed) return
+  this._destroyed = true
+  this.emit('close')
+}
+
+var Pack = function (opts) {
+  if (!(this instanceof Pack)) return new Pack(opts)
+  Readable.call(this, opts)
+
+  this._drain = noop
+  this._finalized = false
+  this._finalizing = false
+  this._destroyed = false
+  this._stream = null
+}
+
+inherits(Pack, Readable)
+
+Pack.prototype.entry = function (header, buffer, callback) {
+  if (this._stream) throw new Error('already piping an entry')
+  if (this._finalized || this._destroyed) return
+
+  if (typeof buffer === 'function') {
+    callback = buffer
+    buffer = null
+  }
+
+  if (!callback) callback = noop
+
+  var self = this
+
+  if (!header.size || header.type === 'symlink') header.size = 0
+  if (!header.type) header.type = modeToType(header.mode)
+  if (!header.mode) header.mode = header.type === 'directory' ? DMODE : FMODE
+  if (!header.uid) header.uid = 0
+  if (!header.gid) header.gid = 0
+  if (!header.mtime) header.mtime = new Date()
+
+  if (typeof buffer === 'string') buffer = Buffer.from(buffer)
+  if (Buffer.isBuffer(buffer)) {
+    header.size = buffer.length
+    this._encode(header)
+    var ok = this.push(buffer)
+    overflow(self, header.size)
+    if (ok) process.nextTick(callback)
+    else this._drain = callback
+    return new Void()
+  }
+
+  if (header.type === 'symlink' && !header.linkname) {
+    var linkSink = new LinkSink()
+    eos(linkSink, function (err) {
+      if (err) { // stream was closed
+        self.destroy()
+        return callback(err)
+      }
+
+      header.linkname = linkSink.linkname
+      self._encode(header)
+      callback()
+    })
+
+    return linkSink
+  }
+
+  this._encode(header)
+
+  if (header.type !== 'file' && header.type !== 'contiguous-file') {
+    process.nextTick(callback)
+    return new Void()
+  }
+
+  var sink = new Sink(this)
+
+  this._stream = sink
+
+  eos(sink, function (err) {
+    self._stream = null
+
+    if (err) { // stream was closed
+      self.destroy()
+      return callback(err)
+    }
+
+    if (sink.written !== header.size) { // corrupting tar
+      self.destroy()
+      return callback(new Error('size mismatch'))
+    }
+
+    overflow(self, header.size)
+    if (self._finalizing) self.finalize()
+    callback()
+  })
+
+  return sink
+}
+
+Pack.prototype.finalize = function () {
+  if (this._stream) {
+    this._finalizing = true
+    return
+  }
+
+  if (this._finalized) return
+  this._finalized = true
+  this.push(END_OF_TAR)
+  this.push(null)
+}
+
+Pack.prototype.destroy = function (err) {
+  if (this._destroyed) return
+  this._destroyed = true
+
+  if (err) this.emit('error', err)
+  this.emit('close')
+  if (this._stream && this._stream.destroy) this._stream.destroy()
+}
+
+Pack.prototype._encode = function (header) {
+  if (!header.pax) {
+    var buf = headers.encode(header)
+    if (buf) {
+      this.push(buf)
+      return
+    }
+  }
+  this._encodePax(header)
+}
+
+Pack.prototype._encodePax = function (header) {
+  var paxHeader = headers.encodePax({
+    name: header.name,
+    linkname: header.linkname,
+    pax: header.pax
+  })
+
+  var newHeader = {
+    name: 'PaxHeader',
+    mode: header.mode,
+    uid: header.uid,
+    gid: header.gid,
+    size: paxHeader.length,
+    mtime: header.mtime,
+    type: 'pax-header',
+    linkname: header.linkname && 'PaxHeader',
+    uname: header.uname,
+    gname: header.gname,
+    devmajor: header.devmajor,
+    devminor: header.devminor
+  }
+
+  this.push(headers.encode(newHeader))
+  this.push(paxHeader)
+  overflow(this, paxHeader.length)
+
+  newHeader.size = header.size
+  newHeader.type = header.type
+  this.push(headers.encode(newHeader))
+}
+
+Pack.prototype._read = function (n) {
+  var drain = this._drain
+  this._drain = noop
+  drain()
+}
+
+module.exports = Pack
diff --git a/server/node_modules/tar-stream/package.json b/server/node_modules/tar-stream/package.json
new file mode 100644
index 0000000..d717dfc
--- /dev/null
+++ b/server/node_modules/tar-stream/package.json
@@ -0,0 +1,58 @@
+{
+  "name": "tar-stream",
+  "version": "2.2.0",
+  "description": "tar-stream is a streaming tar parser and generator and nothing else. It is streams2 and operates purely using streams which means you can easily extract/parse tarballs without ever hitting the file system.",
+  "author": "Mathias Buus <mathiasbuus@gmail.com>",
+  "dependencies": {
+    "bl": "^4.0.3",
+    "end-of-stream": "^1.4.1",
+    "fs-constants": "^1.0.0",
+    "inherits": "^2.0.3",
+    "readable-stream": "^3.1.1"
+  },
+  "devDependencies": {
+    "concat-stream": "^2.0.0",
+    "standard": "^12.0.1",
+    "tape": "^4.9.2"
+  },
+  "scripts": {
+    "test": "standard && tape test/extract.js test/pack.js",
+    "test-all": "standard && tape test/*.js"
+  },
+  "keywords": [
+    "tar",
+    "tarball",
+    "parse",
+    "parser",
+    "generate",
+    "generator",
+    "stream",
+    "stream2",
+    "streams",
+    "streams2",
+    "streaming",
+    "pack",
+    "extract",
+    "modify"
+  ],
+  "bugs": {
+    "url": "https://github.com/mafintosh/tar-stream/issues"
+  },
+  "homepage": "https://github.com/mafintosh/tar-stream",
+  "main": "index.js",
+  "files": [
+    "*.js",
+    "LICENSE"
+  ],
+  "directories": {
+    "test": "test"
+  },
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/mafintosh/tar-stream.git"
+  },
+  "engines": {
+    "node": ">=6"
+  }
+}
diff --git a/server/node_modules/tar-stream/sandbox.js b/server/node_modules/tar-stream/sandbox.js
new file mode 100644
index 0000000..9b82d40
--- /dev/null
+++ b/server/node_modules/tar-stream/sandbox.js
@@ -0,0 +1,11 @@
+const tar = require('tar-stream')
+const fs = require('fs')
+const path = require('path')
+const pipeline = require('pump') // eequire('stream').pipeline
+
+fs.createReadStream('test.tar')
+  .pipe(tar.extract())
+  .on('entry', function (header, stream, done) {
+    console.log(header.name)
+    pipeline(stream, fs.createWriteStream(path.join('/tmp', header.name)), done)
+  })
diff --git a/server/node_modules/tar/LICENSE b/server/node_modules/tar/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/tar/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/tar/README.md b/server/node_modules/tar/README.md
new file mode 100644
index 0000000..f620568
--- /dev/null
+++ b/server/node_modules/tar/README.md
@@ -0,0 +1,1080 @@
+# node-tar
+
+Fast and full-featured Tar for Node.js
+
+The API is designed to mimic the behavior of `tar(1)` on unix systems.
+If you are familiar with how tar works, most of this will hopefully be
+straightforward for you.  If not, then hopefully this module can teach
+you useful unix skills that may come in handy someday :)
+
+## Background
+
+A "tar file" or "tarball" is an archive of file system entries
+(directories, files, links, etc.)  The name comes from "tape archive".
+If you run `man tar` on almost any Unix command line, you'll learn
+quite a bit about what it can do, and its history.
+
+Tar has 5 main top-level commands:
+
+* `c` Create an archive
+* `r` Replace entries within an archive
+* `u` Update entries within an archive (ie, replace if they're newer)
+* `t` List out the contents of an archive
+* `x` Extract an archive to disk
+
+The other flags and options modify how this top level function works.
+
+## High-Level API
+
+These 5 functions are the high-level API.  All of them have a
+single-character name (for unix nerds familiar with `tar(1)`) as well
+as a long name (for everyone else).
+
+All the high-level functions take the following arguments, all three
+of which are optional and may be omitted.
+
+1. `options` - An optional object specifying various options
+2. `paths` - An array of paths to add or extract
+3. `callback` - Called when the command is completed, if async.  (If
+   sync or no file specified, providing a callback throws a
+   `TypeError`.)
+
+If the command is sync (ie, if `options.sync=true`), then the
+callback is not allowed, since the action will be completed immediately.
+
+If a `file` argument is specified, and the command is async, then a
+`Promise` is returned.  In this case, if async, a callback may be
+provided which is called when the command is completed.
+
+If a `file` option is not specified, then a stream is returned.  For
+`create`, this is a readable stream of the generated archive.  For
+`list` and `extract` this is a writable stream that an archive should
+be written into.  If a file is not specified, then a callback is not
+allowed, because you're already getting a stream to work with.
+
+`replace` and `update` only work on existing archives, and so require
+a `file` argument.
+
+Sync commands without a file argument return a stream that acts on its
+input immediately in the same tick.  For readable streams, this means
+that all of the data is immediately available by calling
+`stream.read()`.  For writable streams, it will be acted upon as soon
+as it is provided, but this can be at any time.
+
+### Warnings and Errors
+
+Tar emits warnings and errors for recoverable and unrecoverable situations,
+respectively.  In many cases, a warning only affects a single entry in an
+archive, or is simply informing you that it's modifying an entry to comply
+with the settings provided.
+
+Unrecoverable warnings will always raise an error (ie, emit `'error'` on
+streaming actions, throw for non-streaming sync actions, reject the
+returned Promise for non-streaming async operations, or call a provided
+callback with an `Error` as the first argument).  Recoverable errors will
+raise an error only if `strict: true` is set in the options.
+
+Respond to (recoverable) warnings by listening to the `warn` event.
+Handlers receive 3 arguments:
+
+- `code` String.  One of the error codes below.  This may not match
+  `data.code`, which preserves the original error code from fs and zlib.
+- `message` String.  More details about the error.
+- `data` Metadata about the error.  An `Error` object for errors raised by
+  fs and zlib.  All fields are attached to errors raisd by tar.  Typically
+  contains the following fields, as relevant:
+  - `tarCode` The tar error code.
+  - `code` Either the tar error code, or the error code set by the
+    underlying system.
+  - `file` The archive file being read or written.
+  - `cwd` Working directory for creation and extraction operations.
+  - `entry` The entry object (if it could be created) for `TAR_ENTRY_INFO`,
+    `TAR_ENTRY_INVALID`, and `TAR_ENTRY_ERROR` warnings.
+  - `header` The header object (if it could be created, and the entry could
+    not be created) for `TAR_ENTRY_INFO` and `TAR_ENTRY_INVALID` warnings.
+  - `recoverable` Boolean.  If `false`, then the warning will emit an
+    `error`, even in non-strict mode.
+
+#### Error Codes
+
+* `TAR_ENTRY_INFO`  An informative error indicating that an entry is being
+  modified, but otherwise processed normally.  For example, removing `/` or
+  `C:\` from absolute paths if `preservePaths` is not set.
+
+* `TAR_ENTRY_INVALID` An indication that a given entry is not a valid tar
+  archive entry, and will be skipped.  This occurs when:
+  - a checksum fails,
+  - a `linkpath` is missing for a link type, or
+  - a `linkpath` is provided for a non-link type.
+
+  If every entry in a parsed archive raises an `TAR_ENTRY_INVALID` error,
+  then the archive is presumed to be unrecoverably broken, and
+  `TAR_BAD_ARCHIVE` will be raised.
+
+* `TAR_ENTRY_ERROR` The entry appears to be a valid tar archive entry, but
+  encountered an error which prevented it from being unpacked.  This occurs
+  when:
+  - an unrecoverable fs error happens during unpacking,
+  - an entry is trying to extract into an excessively deep
+    location (by default, limited to 1024 subfolders),
+  - an entry has `..` in the path and `preservePaths` is not set, or
+  - an entry is extracting through a symbolic link, when `preservePaths` is
+    not set.
+
+* `TAR_ENTRY_UNSUPPORTED`  An indication that a given entry is
+  a valid archive entry, but of a type that is unsupported, and so will be
+  skipped in archive creation or extracting.
+
+* `TAR_ABORT`  When parsing gzipped-encoded archives, the parser will
+  abort the parse process raise a warning for any zlib errors encountered.
+  Aborts are considered unrecoverable for both parsing and unpacking.
+
+* `TAR_BAD_ARCHIVE`  The archive file is totally hosed.  This can happen for
+  a number of reasons, and always occurs at the end of a parse or extract:
+
+  - An entry body was truncated before seeing the full number of bytes.
+  - The archive contained only invalid entries, indicating that it is
+    likely not an archive, or at least, not an archive this library can
+    parse.
+
+  `TAR_BAD_ARCHIVE` is considered informative for parse operations, but
+  unrecoverable for extraction.  Note that, if encountered at the end of an
+  extraction, tar WILL still have extracted as much it could from the
+  archive, so there may be some garbage files to clean up.
+
+Errors that occur deeper in the system (ie, either the filesystem or zlib)
+will have their error codes left intact, and a `tarCode` matching one of
+the above will be added to the warning metadata or the raised error object.
+
+Errors generated by tar will have one of the above codes set as the
+`error.code` field as well, but since errors originating in zlib or fs will
+have their original codes, it's better to read `error.tarCode` if you wish
+to see how tar is handling the issue.
+
+### Examples
+
+The API mimics the `tar(1)` command line functionality, with aliases
+for more human-readable option and function names.  The goal is that
+if you know how to use `tar(1)` in Unix, then you know how to use
+`require('tar')` in JavaScript.
+
+To replicate `tar czf my-tarball.tgz files and folders`, you'd do:
+
+```js
+tar.c(
+  {
+    gzip: <true|gzip options>,
+    file: 'my-tarball.tgz'
+  },
+  ['some', 'files', 'and', 'folders']
+).then(_ => { .. tarball has been created .. })
+```
+
+To replicate `tar cz files and folders > my-tarball.tgz`, you'd do:
+
+```js
+tar.c( // or tar.create
+  {
+    gzip: <true|gzip options>
+  },
+  ['some', 'files', 'and', 'folders']
+).pipe(fs.createWriteStream('my-tarball.tgz'))
+```
+
+To replicate `tar xf my-tarball.tgz` you'd do:
+
+```js
+tar.x(  // or tar.extract(
+  {
+    file: 'my-tarball.tgz'
+  }
+).then(_=> { .. tarball has been dumped in cwd .. })
+```
+
+To replicate `cat my-tarball.tgz | tar x -C some-dir --strip=1`:
+
+```js
+fs.createReadStream('my-tarball.tgz').pipe(
+  tar.x({
+    strip: 1,
+    C: 'some-dir' // alias for cwd:'some-dir', also ok
+  })
+)
+```
+
+To replicate `tar tf my-tarball.tgz`, do this:
+
+```js
+tar.t({
+  file: 'my-tarball.tgz',
+  onentry: entry => { .. do whatever with it .. }
+})
+```
+
+For example, to just get the list of filenames from an archive:
+
+```js
+const getEntryFilenames = async tarballFilename => {
+  const filenames = []
+  await tar.t({
+    file: tarballFilename,
+    onentry: entry => filenames.push(entry.path),
+  })
+  return filenames
+}
+```
+
+To replicate `cat my-tarball.tgz | tar t` do:
+
+```js
+fs.createReadStream('my-tarball.tgz')
+  .pipe(tar.t())
+  .on('entry', entry => { .. do whatever with it .. })
+```
+
+To do anything synchronous, add `sync: true` to the options.  Note
+that sync functions don't take a callback and don't return a promise.
+When the function returns, it's already done.  Sync methods without a
+file argument return a sync stream, which flushes immediately.  But,
+of course, it still won't be done until you `.end()` it.
+
+```js
+const getEntryFilenamesSync = tarballFilename => {
+  const filenames = []
+  tar.t({
+    file: tarballFilename,
+    onentry: entry => filenames.push(entry.path),
+    sync: true,
+  })
+  return filenames
+}
+```
+
+To filter entries, add `filter: <function>` to the options.
+Tar-creating methods call the filter with `filter(path, stat)`.
+Tar-reading methods (including extraction) call the filter with
+`filter(path, entry)`.  The filter is called in the `this`-context of
+the `Pack` or `Unpack` stream object.
+
+The arguments list to `tar t` and `tar x` specify a list of filenames
+to extract or list, so they're equivalent to a filter that tests if
+the file is in the list.
+
+For those who _aren't_ fans of tar's single-character command names:
+
+```
+tar.c === tar.create
+tar.r === tar.replace (appends to archive, file is required)
+tar.u === tar.update (appends if newer, file is required)
+tar.x === tar.extract
+tar.t === tar.list
+```
+
+Keep reading for all the command descriptions and options, as well as
+the low-level API that they are built on.
+
+### tar.c(options, fileList, callback) [alias: tar.create]
+
+Create a tarball archive.
+
+The `fileList` is an array of paths to add to the tarball.  Adding a
+directory also adds its children recursively.
+
+An entry in `fileList` that starts with an `@` symbol is a tar archive
+whose entries will be added.  To add a file that starts with `@`,
+prepend it with `./`.
+
+The following options are supported:
+
+- `file` Write the tarball archive to the specified filename.  If this
+  is specified, then the callback will be fired when the file has been
+  written, and a promise will be returned that resolves when the file
+  is written.  If a filename is not specified, then a Readable Stream
+  will be returned which will emit the file data. [Alias: `f`]
+- `sync` Act synchronously.  If this is set, then any provided file
+  will be fully written after the call to `tar.c`.  If this is set,
+  and a file is not provided, then the resulting stream will already
+  have the data ready to `read` or `emit('data')` as soon as you
+  request it.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `cwd` The current working directory for creating the archive.
+  Defaults to `process.cwd()`.  [Alias: `C`]
+- `prefix` A path portion to prefix onto the entries in the archive.
+- `gzip` Set to any truthy value to create a gzipped archive, or an
+  object with settings for `zlib.Gzip()` [Alias: `z`]
+- `filter` A function that gets called with `(path, stat)` for each
+  entry being added.  Return `true` to add the entry to the archive,
+  or `false` to omit it.
+- `portable` Omit metadata that is system-specific: `ctime`, `atime`,
+  `uid`, `gid`, `uname`, `gname`, `dev`, `ino`, and `nlink`.  Note
+  that `mtime` is still included, because this is necessary for other
+  time-based operations.  Additionally, `mode` is set to a "reasonable
+  default" for most unix systems, based on a `umask` value of `0o22`.
+- `preservePaths` Allow absolute paths.  By default, `/` is stripped
+  from absolute paths. [Alias: `P`]
+- `mode` The mode to set on the created file archive
+- `noDirRecurse` Do not recursively archive the contents of
+  directories. [Alias: `n`]
+- `follow` Set to true to pack the targets of symbolic links.  Without
+  this option, symbolic links are archived as such. [Alias: `L`, `h`]
+- `noPax` Suppress pax extended headers.  Note that this means that
+  long paths and linkpaths will be truncated, and large or negative
+  numeric values may be interpreted incorrectly.
+- `noMtime` Set to true to omit writing `mtime` values for entries.
+  Note that this prevents using other mtime-based features like
+  `tar.update` or the `keepNewer` option with the resulting tar archive.
+  [Alias: `m`, `no-mtime`]
+- `mtime` Set to a `Date` object to force a specific `mtime` for
+  everything added to the archive.  Overridden by `noMtime`.
+
+The following options are mostly internal, but can be modified in some
+advanced use cases, such as re-using caches between runs.
+
+- `linkCache` A Map object containing the device and inode value for
+  any file whose nlink is > 1, to identify hard links.
+- `statCache` A Map object that caches calls `lstat`.
+- `readdirCache` A Map object that caches calls to `readdir`.
+- `jobs` A number specifying how many concurrent jobs to run.
+  Defaults to 4.
+- `maxReadSize` The maximum buffer size for `fs.read()` operations.
+  Defaults to 16 MB.
+
+### tar.x(options, fileList, callback) [alias: tar.extract]
+
+Extract a tarball archive.
+
+The `fileList` is an array of paths to extract from the tarball.  If
+no paths are provided, then all the entries are extracted.
+
+If the archive is gzipped, then tar will detect this and unzip it.
+
+Note that all directories that are created will be forced to be
+writable, readable, and listable by their owner, to avoid cases where
+a directory prevents extraction of child entries by virtue of its
+mode.
+
+Most extraction errors will cause a `warn` event to be emitted.  If
+the `cwd` is missing, or not a directory, then the extraction will
+fail completely.
+
+The following options are supported:
+
+- `cwd` Extract files relative to the specified directory.  Defaults
+  to `process.cwd()`.  If provided, this must exist and must be a
+  directory. [Alias: `C`]
+- `file` The archive file to extract.  If not specified, then a
+  Writable stream is returned where the archive data should be
+  written. [Alias: `f`]
+- `sync` Create files and directories synchronously.
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `filter` A function that gets called with `(path, entry)` for each
+  entry being unpacked.  Return `true` to unpack the entry from the
+  archive, or `false` to skip it.
+- `newer` Set to true to keep the existing file on disk if it's newer
+  than the file in the archive. [Alias: `keep-newer`,
+  `keep-newer-files`]
+- `keep` Do not overwrite existing files.  In particular, if a file
+  appears more than once in an archive, later copies will not
+  overwrite earlier copies. [Alias: `k`, `keep-existing`]
+- `preservePaths` Allow absolute paths, paths containing `..`, and
+  extracting through symbolic links.  By default, `/` is stripped from
+  absolute paths, `..` paths are not extracted, and any file whose
+  location would be modified by a symbolic link is not extracted.
+  [Alias: `P`]
+- `unlink` Unlink files before creating them.  Without this option,
+  tar overwrites existing files, which preserves existing hardlinks.
+  With this option, existing hardlinks will be broken, as will any
+  symlink that would affect the location of an extracted file. [Alias:
+  `U`]
+- `strip` Remove the specified number of leading path elements.
+  Pathnames with fewer elements will be silently skipped.  Note that
+  the pathname is edited after applying the filter, but before
+  security checks. [Alias: `strip-components`, `stripComponents`]
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `preserveOwner` If true, tar will set the `uid` and `gid` of
+  extracted entries to the `uid` and `gid` fields in the archive.
+  This defaults to true when run as root, and false otherwise.  If
+  false, then files and directories will be set with the owner and
+  group of the user running the process.  This is similar to `-p` in
+  `tar(1)`, but ACLs and other system-specific data is never unpacked
+  in this implementation, and modes are set by default already.
+  [Alias: `p`]
+- `uid` Set to a number to force ownership of all extracted files and
+  folders, and all implicitly created directories, to be owned by the
+  specified user id, regardless of the `uid` field in the archive.
+  Cannot be used along with `preserveOwner`.  Requires also setting a
+  `gid` option.
+- `gid` Set to a number to force ownership of all extracted files and
+  folders, and all implicitly created directories, to be owned by the
+  specified group id, regardless of the `gid` field in the archive.
+  Cannot be used along with `preserveOwner`.  Requires also setting a
+  `uid` option.
+- `noMtime` Set to true to omit writing `mtime` value for extracted
+  entries. [Alias: `m`, `no-mtime`]
+- `transform` Provide a function that takes an `entry` object, and
+  returns a stream, or any falsey value.  If a stream is provided,
+  then that stream's data will be written instead of the contents of
+  the archive entry.  If a falsey value is provided, then the entry is
+  written to disk as normal.  (To exclude items from extraction, use
+  the `filter` option described above.)
+- `onentry` A function that gets called with `(entry)` for each entry
+  that passes the filter.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `noChmod` Set to true to omit calling `fs.chmod()` to ensure that the
+  extracted file matches the entry mode.  This also suppresses the call to
+  `process.umask()` to determine the default umask value, since tar will
+  extract with whatever mode is provided, and let the process `umask` apply
+  normally.
+- `maxDepth` The maximum depth of subfolders to extract into. This
+  defaults to 1024. Anything deeper than the limit will raise a
+  warning and skip the entry. Set to `Infinity` to remove the
+  limitation.
+
+The following options are mostly internal, but can be modified in some
+advanced use cases, such as re-using caches between runs.
+
+- `maxReadSize` The maximum buffer size for `fs.read()` operations.
+  Defaults to 16 MB.
+- `umask` Filter the modes of entries like `process.umask()`.
+- `dmode` Default mode for directories
+- `fmode` Default mode for files
+- `dirCache` A Map object of which directories exist.
+- `maxMetaEntrySize` The maximum size of meta entries that is
+  supported.  Defaults to 1 MB.
+
+Note that using an asynchronous stream type with the `transform`
+option will cause undefined behavior in sync extractions.
+[MiniPass](http://npm.im/minipass)-based streams are designed for this
+use case.
+
+### tar.t(options, fileList, callback) [alias: tar.list]
+
+List the contents of a tarball archive.
+
+The `fileList` is an array of paths to list from the tarball.  If
+no paths are provided, then all the entries are listed.
+
+If the archive is gzipped, then tar will detect this and unzip it.
+
+If the `file` option is _not_ provided, then returns an event emitter that
+emits `entry` events with `tar.ReadEntry` objects.  However, they don't
+emit `'data'` or `'end'` events.  (If you want to get actual readable
+entries, use the `tar.Parse` class instead.)
+
+If a `file` option _is_ provided, then the return value will be a promise
+that resolves when the file has been fully traversed in async mode, or
+`undefined` if `sync: true` is set.  Thus, you _must_ specify an `onentry`
+method in order to do anything useful with the data it parses.
+
+The following options are supported:
+
+- `file` The archive file to list.  If not specified, then a
+  Writable stream is returned where the archive data should be
+  written. [Alias: `f`]
+- `sync` Read the specified file synchronously.  (This has no effect
+  when a file option isn't specified, because entries are emitted as
+  fast as they are parsed from the stream anyway.)
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `filter` A function that gets called with `(path, entry)` for each
+  entry being listed.  Return `true` to emit the entry from the
+  archive, or `false` to skip it.
+- `onentry` A function that gets called with `(entry)` for each entry
+  that passes the filter.  This is important for when `file` is set,
+  because there is no other way to do anything useful with this method.
+- `maxReadSize` The maximum buffer size for `fs.read()` operations.
+  Defaults to 16 MB.
+- `noResume` By default, `entry` streams are resumed immediately after
+  the call to `onentry`.  Set `noResume: true` to suppress this
+  behavior.  Note that by opting into this, the stream will never
+  complete until the entry data is consumed.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+
+### tar.u(options, fileList, callback) [alias: tar.update]
+
+Add files to an archive if they are newer than the entry already in
+the tarball archive.
+
+The `fileList` is an array of paths to add to the tarball.  Adding a
+directory also adds its children recursively.
+
+An entry in `fileList` that starts with an `@` symbol is a tar archive
+whose entries will be added.  To add a file that starts with `@`,
+prepend it with `./`.
+
+The following options are supported:
+
+- `file` Required. Write the tarball archive to the specified
+  filename. [Alias: `f`]
+- `sync` Act synchronously.  If this is set, then any provided file
+  will be fully written after the call to `tar.c`.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `cwd` The current working directory for adding entries to the
+  archive.  Defaults to `process.cwd()`.  [Alias: `C`]
+- `prefix` A path portion to prefix onto the entries in the archive.
+- `gzip` Set to any truthy value to create a gzipped archive, or an
+  object with settings for `zlib.Gzip()` [Alias: `z`]
+- `filter` A function that gets called with `(path, stat)` for each
+  entry being added.  Return `true` to add the entry to the archive,
+  or `false` to omit it.
+- `portable` Omit metadata that is system-specific: `ctime`, `atime`,
+  `uid`, `gid`, `uname`, `gname`, `dev`, `ino`, and `nlink`.  Note
+  that `mtime` is still included, because this is necessary for other
+  time-based operations.  Additionally, `mode` is set to a "reasonable
+  default" for most unix systems, based on a `umask` value of `0o22`.
+- `preservePaths` Allow absolute paths.  By default, `/` is stripped
+  from absolute paths. [Alias: `P`]
+- `maxReadSize` The maximum buffer size for `fs.read()` operations.
+  Defaults to 16 MB.
+- `noDirRecurse` Do not recursively archive the contents of
+  directories. [Alias: `n`]
+- `follow` Set to true to pack the targets of symbolic links.  Without
+  this option, symbolic links are archived as such. [Alias: `L`, `h`]
+- `noPax` Suppress pax extended headers.  Note that this means that
+  long paths and linkpaths will be truncated, and large or negative
+  numeric values may be interpreted incorrectly.
+- `noMtime` Set to true to omit writing `mtime` values for entries.
+  Note that this prevents using other mtime-based features like
+  `tar.update` or the `keepNewer` option with the resulting tar archive.
+  [Alias: `m`, `no-mtime`]
+- `mtime` Set to a `Date` object to force a specific `mtime` for
+  everything added to the archive.  Overridden by `noMtime`.
+
+### tar.r(options, fileList, callback) [alias: tar.replace]
+
+Add files to an existing archive.  Because later entries override
+earlier entries, this effectively replaces any existing entries.
+
+The `fileList` is an array of paths to add to the tarball.  Adding a
+directory also adds its children recursively.
+
+An entry in `fileList` that starts with an `@` symbol is a tar archive
+whose entries will be added.  To add a file that starts with `@`,
+prepend it with `./`.
+
+The following options are supported:
+
+- `file` Required. Write the tarball archive to the specified
+  filename. [Alias: `f`]
+- `sync` Act synchronously.  If this is set, then any provided file
+  will be fully written after the call to `tar.c`.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `cwd` The current working directory for adding entries to the
+  archive.  Defaults to `process.cwd()`.  [Alias: `C`]
+- `prefix` A path portion to prefix onto the entries in the archive.
+- `gzip` Set to any truthy value to create a gzipped archive, or an
+  object with settings for `zlib.Gzip()` [Alias: `z`]
+- `filter` A function that gets called with `(path, stat)` for each
+  entry being added.  Return `true` to add the entry to the archive,
+  or `false` to omit it.
+- `portable` Omit metadata that is system-specific: `ctime`, `atime`,
+  `uid`, `gid`, `uname`, `gname`, `dev`, `ino`, and `nlink`.  Note
+  that `mtime` is still included, because this is necessary for other
+  time-based operations.  Additionally, `mode` is set to a "reasonable
+  default" for most unix systems, based on a `umask` value of `0o22`.
+- `preservePaths` Allow absolute paths.  By default, `/` is stripped
+  from absolute paths. [Alias: `P`]
+- `maxReadSize` The maximum buffer size for `fs.read()` operations.
+  Defaults to 16 MB.
+- `noDirRecurse` Do not recursively archive the contents of
+  directories. [Alias: `n`]
+- `follow` Set to true to pack the targets of symbolic links.  Without
+  this option, symbolic links are archived as such. [Alias: `L`, `h`]
+- `noPax` Suppress pax extended headers.  Note that this means that
+  long paths and linkpaths will be truncated, and large or negative
+  numeric values may be interpreted incorrectly.
+- `noMtime` Set to true to omit writing `mtime` values for entries.
+  Note that this prevents using other mtime-based features like
+  `tar.update` or the `keepNewer` option with the resulting tar archive.
+  [Alias: `m`, `no-mtime`]
+- `mtime` Set to a `Date` object to force a specific `mtime` for
+  everything added to the archive.  Overridden by `noMtime`.
+
+
+## Low-Level API
+
+### class tar.Pack
+
+A readable tar stream.
+
+Has all the standard readable stream interface stuff.  `'data'` and
+`'end'` events, `read()` method, `pause()` and `resume()`, etc.
+
+#### constructor(options)
+
+The following options are supported:
+
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `cwd` The current working directory for creating the archive.
+  Defaults to `process.cwd()`.
+- `prefix` A path portion to prefix onto the entries in the archive.
+- `gzip` Set to any truthy value to create a gzipped archive, or an
+  object with settings for `zlib.Gzip()`
+- `filter` A function that gets called with `(path, stat)` for each
+  entry being added.  Return `true` to add the entry to the archive,
+  or `false` to omit it.
+- `portable` Omit metadata that is system-specific: `ctime`, `atime`,
+  `uid`, `gid`, `uname`, `gname`, `dev`, `ino`, and `nlink`.  Note
+  that `mtime` is still included, because this is necessary for other
+  time-based operations.  Additionally, `mode` is set to a "reasonable
+  default" for most unix systems, based on a `umask` value of `0o22`.
+- `preservePaths` Allow absolute paths.  By default, `/` is stripped
+  from absolute paths.
+- `linkCache` A Map object containing the device and inode value for
+  any file whose nlink is > 1, to identify hard links.
+- `statCache` A Map object that caches calls `lstat`.
+- `readdirCache` A Map object that caches calls to `readdir`.
+- `jobs` A number specifying how many concurrent jobs to run.
+  Defaults to 4.
+- `maxReadSize` The maximum buffer size for `fs.read()` operations.
+  Defaults to 16 MB.
+- `noDirRecurse` Do not recursively archive the contents of
+  directories.
+- `follow` Set to true to pack the targets of symbolic links.  Without
+  this option, symbolic links are archived as such.
+- `noPax` Suppress pax extended headers.  Note that this means that
+  long paths and linkpaths will be truncated, and large or negative
+  numeric values may be interpreted incorrectly.
+- `noMtime` Set to true to omit writing `mtime` values for entries.
+  Note that this prevents using other mtime-based features like
+  `tar.update` or the `keepNewer` option with the resulting tar archive.
+- `mtime` Set to a `Date` object to force a specific `mtime` for
+  everything added to the archive.  Overridden by `noMtime`.
+
+#### add(path)
+
+Adds an entry to the archive.  Returns the Pack stream.
+
+#### write(path)
+
+Adds an entry to the archive.  Returns true if flushed.
+
+#### end()
+
+Finishes the archive.
+
+### class tar.Pack.Sync
+
+Synchronous version of `tar.Pack`.
+
+### class tar.Unpack
+
+A writable stream that unpacks a tar archive onto the file system.
+
+All the normal writable stream stuff is supported.  `write()` and
+`end()` methods, `'drain'` events, etc.
+
+Note that all directories that are created will be forced to be
+writable, readable, and listable by their owner, to avoid cases where
+a directory prevents extraction of child entries by virtue of its
+mode.
+
+`'close'` is emitted when it's done writing stuff to the file system.
+
+Most unpack errors will cause a `warn` event to be emitted.  If the
+`cwd` is missing, or not a directory, then an error will be emitted.
+
+#### constructor(options)
+
+- `cwd` Extract files relative to the specified directory.  Defaults
+  to `process.cwd()`.  If provided, this must exist and must be a
+  directory.
+- `filter` A function that gets called with `(path, entry)` for each
+  entry being unpacked.  Return `true` to unpack the entry from the
+  archive, or `false` to skip it.
+- `newer` Set to true to keep the existing file on disk if it's newer
+  than the file in the archive.
+- `keep` Do not overwrite existing files.  In particular, if a file
+  appears more than once in an archive, later copies will not
+  overwrite earlier copies.
+- `preservePaths` Allow absolute paths, paths containing `..`, and
+  extracting through symbolic links.  By default, `/` is stripped from
+  absolute paths, `..` paths are not extracted, and any file whose
+  location would be modified by a symbolic link is not extracted.
+- `unlink` Unlink files before creating them.  Without this option,
+  tar overwrites existing files, which preserves existing hardlinks.
+  With this option, existing hardlinks will be broken, as will any
+  symlink that would affect the location of an extracted file.
+- `strip` Remove the specified number of leading path elements.
+  Pathnames with fewer elements will be silently skipped.  Note that
+  the pathname is edited after applying the filter, but before
+  security checks.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `umask` Filter the modes of entries like `process.umask()`.
+- `dmode` Default mode for directories
+- `fmode` Default mode for files
+- `dirCache` A Map object of which directories exist.
+- `maxMetaEntrySize` The maximum size of meta entries that is
+  supported.  Defaults to 1 MB.
+- `preserveOwner` If true, tar will set the `uid` and `gid` of
+  extracted entries to the `uid` and `gid` fields in the archive.
+  This defaults to true when run as root, and false otherwise.  If
+  false, then files and directories will be set with the owner and
+  group of the user running the process.  This is similar to `-p` in
+  `tar(1)`, but ACLs and other system-specific data is never unpacked
+  in this implementation, and modes are set by default already.
+- `win32` True if on a windows platform.  Causes behavior where
+  filenames containing `<|>?` chars are converted to
+  windows-compatible values while being unpacked.
+- `uid` Set to a number to force ownership of all extracted files and
+  folders, and all implicitly created directories, to be owned by the
+  specified user id, regardless of the `uid` field in the archive.
+  Cannot be used along with `preserveOwner`.  Requires also setting a
+  `gid` option.
+- `gid` Set to a number to force ownership of all extracted files and
+  folders, and all implicitly created directories, to be owned by the
+  specified group id, regardless of the `gid` field in the archive.
+  Cannot be used along with `preserveOwner`.  Requires also setting a
+  `uid` option.
+- `noMtime` Set to true to omit writing `mtime` value for extracted
+  entries.
+- `transform` Provide a function that takes an `entry` object, and
+  returns a stream, or any falsey value.  If a stream is provided,
+  then that stream's data will be written instead of the contents of
+  the archive entry.  If a falsey value is provided, then the entry is
+  written to disk as normal.  (To exclude items from extraction, use
+  the `filter` option described above.)
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `onentry` A function that gets called with `(entry)` for each entry
+  that passes the filter.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `noChmod` Set to true to omit calling `fs.chmod()` to ensure that the
+  extracted file matches the entry mode.  This also suppresses the call to
+  `process.umask()` to determine the default umask value, since tar will
+  extract with whatever mode is provided, and let the process `umask` apply
+  normally.
+- `maxDepth` The maximum depth of subfolders to extract into. This
+  defaults to 1024. Anything deeper than the limit will raise a
+  warning and skip the entry. Set to `Infinity` to remove the
+  limitation.
+
+### class tar.Unpack.Sync
+
+Synchronous version of `tar.Unpack`.
+
+Note that using an asynchronous stream type with the `transform`
+option will cause undefined behavior in sync unpack streams.
+[MiniPass](http://npm.im/minipass)-based streams are designed for this
+use case.
+
+### class tar.Parse
+
+A writable stream that parses a tar archive stream.  All the standard
+writable stream stuff is supported.
+
+If the archive is gzipped, then tar will detect this and unzip it.
+
+Emits `'entry'` events with `tar.ReadEntry` objects, which are
+themselves readable streams that you can pipe wherever.
+
+Each `entry` will not emit until the one before it is flushed through,
+so make sure to either consume the data (with `on('data', ...)` or
+`.pipe(...)`) or throw it away with `.resume()` to keep the stream
+flowing.
+
+#### constructor(options)
+
+Returns an event emitter that emits `entry` events with
+`tar.ReadEntry` objects.
+
+The following options are supported:
+
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `filter` A function that gets called with `(path, entry)` for each
+  entry being listed.  Return `true` to emit the entry from the
+  archive, or `false` to skip it.
+- `onentry` A function that gets called with `(entry)` for each entry
+  that passes the filter.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+
+#### abort(error)
+
+Stop all parsing activities.  This is called when there are zlib
+errors.  It also emits an unrecoverable warning with the error provided.
+
+### class tar.ReadEntry extends [MiniPass](http://npm.im/minipass)
+
+A representation of an entry that is being read out of a tar archive.
+
+It has the following fields:
+
+- `extended` The extended metadata object provided to the constructor.
+- `globalExtended` The global extended metadata object provided to the
+  constructor.
+- `remain` The number of bytes remaining to be written into the
+  stream.
+- `blockRemain` The number of 512-byte blocks remaining to be written
+  into the stream.
+- `ignore` Whether this entry should be ignored.
+- `meta` True if this represents metadata about the next entry, false
+  if it represents a filesystem object.
+- All the fields from the header, extended header, and global extended
+  header are added to the ReadEntry object.  So it has `path`, `type`,
+  `size`, `mode`, and so on.
+
+#### constructor(header, extended, globalExtended)
+
+Create a new ReadEntry object with the specified header, extended
+header, and global extended header values.
+
+### class tar.WriteEntry extends [MiniPass](http://npm.im/minipass)
+
+A representation of an entry that is being written from the file
+system into a tar archive.
+
+Emits data for the Header, and for the Pax Extended Header if one is
+required, as well as any body data.
+
+Creating a WriteEntry for a directory does not also create
+WriteEntry objects for all of the directory contents.
+
+It has the following fields:
+
+- `path` The path field that will be written to the archive.  By
+  default, this is also the path from the cwd to the file system
+  object.
+- `portable` Omit metadata that is system-specific: `ctime`, `atime`,
+  `uid`, `gid`, `uname`, `gname`, `dev`, `ino`, and `nlink`.  Note
+  that `mtime` is still included, because this is necessary for other
+  time-based operations.  Additionally, `mode` is set to a "reasonable
+  default" for most unix systems, based on a `umask` value of `0o22`.
+- `myuid` If supported, the uid of the user running the current
+  process.
+- `myuser` The `env.USER` string if set, or `''`.  Set as the entry
+  `uname` field if the file's `uid` matches `this.myuid`.
+- `maxReadSize` The maximum buffer size for `fs.read()` operations.
+  Defaults to 1 MB.
+- `linkCache` A Map object containing the device and inode value for
+  any file whose nlink is > 1, to identify hard links.
+- `statCache` A Map object that caches calls `lstat`.
+- `preservePaths` Allow absolute paths.  By default, `/` is stripped
+  from absolute paths.
+- `cwd` The current working directory for creating the archive.
+  Defaults to `process.cwd()`.
+- `absolute` The absolute path to the entry on the filesystem.  By
+  default, this is `path.resolve(this.cwd, this.path)`, but it can be
+  overridden explicitly.
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `win32` True if on a windows platform.  Causes behavior where paths
+  replace `\` with `/` and filenames containing the windows-compatible
+  forms of `<|>?:` characters are converted to actual `<|>?:` characters
+  in the archive.
+- `noPax` Suppress pax extended headers.  Note that this means that
+  long paths and linkpaths will be truncated, and large or negative
+  numeric values may be interpreted incorrectly.
+- `noMtime` Set to true to omit writing `mtime` values for entries.
+  Note that this prevents using other mtime-based features like
+  `tar.update` or the `keepNewer` option with the resulting tar archive.
+
+
+#### constructor(path, options)
+
+`path` is the path of the entry as it is written in the archive.
+
+The following options are supported:
+
+- `portable` Omit metadata that is system-specific: `ctime`, `atime`,
+  `uid`, `gid`, `uname`, `gname`, `dev`, `ino`, and `nlink`.  Note
+  that `mtime` is still included, because this is necessary for other
+  time-based operations.  Additionally, `mode` is set to a "reasonable
+  default" for most unix systems, based on a `umask` value of `0o22`.
+- `maxReadSize` The maximum buffer size for `fs.read()` operations.
+  Defaults to 1 MB.
+- `linkCache` A Map object containing the device and inode value for
+  any file whose nlink is > 1, to identify hard links.
+- `statCache` A Map object that caches calls `lstat`.
+- `preservePaths` Allow absolute paths.  By default, `/` is stripped
+  from absolute paths.
+- `cwd` The current working directory for creating the archive.
+  Defaults to `process.cwd()`.
+- `absolute` The absolute path to the entry on the filesystem.  By
+  default, this is `path.resolve(this.cwd, this.path)`, but it can be
+  overridden explicitly.
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `win32` True if on a windows platform.  Causes behavior where paths
+  replace `\` with `/`.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `noMtime` Set to true to omit writing `mtime` values for entries.
+  Note that this prevents using other mtime-based features like
+  `tar.update` or the `keepNewer` option with the resulting tar archive.
+- `umask` Set to restrict the modes on the entries in the archive,
+  somewhat like how umask works on file creation.  Defaults to
+  `process.umask()` on unix systems, or `0o22` on Windows.
+
+#### warn(message, data)
+
+If strict, emit an error with the provided message.
+
+Othewise, emit a `'warn'` event with the provided message and data.
+
+### class tar.WriteEntry.Sync
+
+Synchronous version of tar.WriteEntry
+
+### class tar.WriteEntry.Tar
+
+A version of tar.WriteEntry that gets its data from a tar.ReadEntry
+instead of from the filesystem.
+
+#### constructor(readEntry, options)
+
+`readEntry` is the entry being read out of another archive.
+
+The following options are supported:
+
+- `portable` Omit metadata that is system-specific: `ctime`, `atime`,
+  `uid`, `gid`, `uname`, `gname`, `dev`, `ino`, and `nlink`.  Note
+  that `mtime` is still included, because this is necessary for other
+  time-based operations.  Additionally, `mode` is set to a "reasonable
+  default" for most unix systems, based on a `umask` value of `0o22`.
+- `preservePaths` Allow absolute paths.  By default, `/` is stripped
+  from absolute paths.
+- `strict` Treat warnings as crash-worthy errors.  Default false.
+- `onwarn` A function that will get called with `(code, message, data)` for
+  any warnings encountered.  (See "Warnings and Errors")
+- `noMtime` Set to true to omit writing `mtime` values for entries.
+  Note that this prevents using other mtime-based features like
+  `tar.update` or the `keepNewer` option with the resulting tar archive.
+
+### class tar.Header
+
+A class for reading and writing header blocks.
+
+It has the following fields:
+
+- `nullBlock` True if decoding a block which is entirely composed of
+  `0x00` null bytes.  (Useful because tar files are terminated by
+  at least 2 null blocks.)
+- `cksumValid` True if the checksum in the header is valid, false
+  otherwise.
+- `needPax` True if the values, as encoded, will require a Pax
+  extended header.
+- `path` The path of the entry.
+- `mode` The 4 lowest-order octal digits of the file mode.  That is,
+  read/write/execute permissions for world, group, and owner, and the
+  setuid, setgid, and sticky bits.
+- `uid` Numeric user id of the file owner
+- `gid` Numeric group id of the file owner
+- `size` Size of the file in bytes
+- `mtime` Modified time of the file
+- `cksum` The checksum of the header.  This is generated by adding all
+  the bytes of the header block, treating the checksum field itself as
+  all ascii space characters (that is, `0x20`).
+- `type` The human-readable name of the type of entry this represents,
+  or the alphanumeric key if unknown.
+- `typeKey` The alphanumeric key for the type of entry this header
+  represents.
+- `linkpath` The target of Link and SymbolicLink entries.
+- `uname` Human-readable user name of the file owner
+- `gname` Human-readable group name of the file owner
+- `devmaj` The major portion of the device number.  Always `0` for
+  files, directories, and links.
+- `devmin` The minor portion of the device number.  Always `0` for
+  files, directories, and links.
+- `atime` File access time.
+- `ctime` File change time.
+
+#### constructor(data, [offset=0])
+
+`data` is optional.  It is either a Buffer that should be interpreted
+as a tar Header starting at the specified offset and continuing for
+512 bytes, or a data object of keys and values to set on the header
+object, and eventually encode as a tar Header.
+
+#### decode(block, offset)
+
+Decode the provided buffer starting at the specified offset.
+
+Buffer length must be greater than 512 bytes.
+
+#### set(data)
+
+Set the fields in the data object.
+
+#### encode(buffer, offset)
+
+Encode the header fields into the buffer at the specified offset.
+
+Returns `this.needPax` to indicate whether a Pax Extended Header is
+required to properly encode the specified data.
+
+### class tar.Pax
+
+An object representing a set of key-value pairs in an Pax extended
+header entry.
+
+It has the following fields.  Where the same name is used, they have
+the same semantics as the tar.Header field of the same name.
+
+- `global` True if this represents a global extended header, or false
+  if it is for a single entry.
+- `atime`
+- `charset`
+- `comment`
+- `ctime`
+- `gid`
+- `gname`
+- `linkpath`
+- `mtime`
+- `path`
+- `size`
+- `uid`
+- `uname`
+- `dev`
+- `ino`
+- `nlink`
+
+#### constructor(object, global)
+
+Set the fields set in the object.  `global` is a boolean that defaults
+to false.
+
+#### encode()
+
+Return a Buffer containing the header and body for the Pax extended
+header entry, or `null` if there is nothing to encode.
+
+#### encodeBody()
+
+Return a string representing the body of the pax extended header
+entry.
+
+#### encodeField(fieldName)
+
+Return a string representing the key/value encoding for the specified
+fieldName, or `''` if the field is unset.
+
+### tar.Pax.parse(string, extended, global)
+
+Return a new Pax object created by parsing the contents of the string
+provided.
+
+If the `extended` object is set, then also add the fields from that
+object.  (This is necessary because multiple metadata entries can
+occur in sequence.)
+
+### tar.types
+
+A translation table for the `type` field in tar headers.
+
+#### tar.types.name.get(code)
+
+Get the human-readable name for a given alphanumeric code.
+
+#### tar.types.code.get(name)
+
+Get the alphanumeric code for a given human-readable name.
diff --git a/server/node_modules/tar/index.js b/server/node_modules/tar/index.js
new file mode 100644
index 0000000..c9ae06e
--- /dev/null
+++ b/server/node_modules/tar/index.js
@@ -0,0 +1,18 @@
+'use strict'
+
+// high-level commands
+exports.c = exports.create = require('./lib/create.js')
+exports.r = exports.replace = require('./lib/replace.js')
+exports.t = exports.list = require('./lib/list.js')
+exports.u = exports.update = require('./lib/update.js')
+exports.x = exports.extract = require('./lib/extract.js')
+
+// classes
+exports.Pack = require('./lib/pack.js')
+exports.Unpack = require('./lib/unpack.js')
+exports.Parse = require('./lib/parse.js')
+exports.ReadEntry = require('./lib/read-entry.js')
+exports.WriteEntry = require('./lib/write-entry.js')
+exports.Header = require('./lib/header.js')
+exports.Pax = require('./lib/pax.js')
+exports.types = require('./lib/types.js')
diff --git a/server/node_modules/tar/lib/create.js b/server/node_modules/tar/lib/create.js
new file mode 100644
index 0000000..9c860d4
--- /dev/null
+++ b/server/node_modules/tar/lib/create.js
@@ -0,0 +1,111 @@
+'use strict'
+
+// tar -c
+const hlo = require('./high-level-opt.js')
+
+const Pack = require('./pack.js')
+const fsm = require('fs-minipass')
+const t = require('./list.js')
+const path = require('path')
+
+module.exports = (opt_, files, cb) => {
+  if (typeof files === 'function') {
+    cb = files
+  }
+
+  if (Array.isArray(opt_)) {
+    files = opt_, opt_ = {}
+  }
+
+  if (!files || !Array.isArray(files) || !files.length) {
+    throw new TypeError('no files or directories specified')
+  }
+
+  files = Array.from(files)
+
+  const opt = hlo(opt_)
+
+  if (opt.sync && typeof cb === 'function') {
+    throw new TypeError('callback not supported for sync tar functions')
+  }
+
+  if (!opt.file && typeof cb === 'function') {
+    throw new TypeError('callback only supported with file option')
+  }
+
+  return opt.file && opt.sync ? createFileSync(opt, files)
+    : opt.file ? createFile(opt, files, cb)
+    : opt.sync ? createSync(opt, files)
+    : create(opt, files)
+}
+
+const createFileSync = (opt, files) => {
+  const p = new Pack.Sync(opt)
+  const stream = new fsm.WriteStreamSync(opt.file, {
+    mode: opt.mode || 0o666,
+  })
+  p.pipe(stream)
+  addFilesSync(p, files)
+}
+
+const createFile = (opt, files, cb) => {
+  const p = new Pack(opt)
+  const stream = new fsm.WriteStream(opt.file, {
+    mode: opt.mode || 0o666,
+  })
+  p.pipe(stream)
+
+  const promise = new Promise((res, rej) => {
+    stream.on('error', rej)
+    stream.on('close', res)
+    p.on('error', rej)
+  })
+
+  addFilesAsync(p, files)
+
+  return cb ? promise.then(cb, cb) : promise
+}
+
+const addFilesSync = (p, files) => {
+  files.forEach(file => {
+    if (file.charAt(0) === '@') {
+      t({
+        file: path.resolve(p.cwd, file.slice(1)),
+        sync: true,
+        noResume: true,
+        onentry: entry => p.add(entry),
+      })
+    } else {
+      p.add(file)
+    }
+  })
+  p.end()
+}
+
+const addFilesAsync = (p, files) => {
+  while (files.length) {
+    const file = files.shift()
+    if (file.charAt(0) === '@') {
+      return t({
+        file: path.resolve(p.cwd, file.slice(1)),
+        noResume: true,
+        onentry: entry => p.add(entry),
+      }).then(_ => addFilesAsync(p, files))
+    } else {
+      p.add(file)
+    }
+  }
+  p.end()
+}
+
+const createSync = (opt, files) => {
+  const p = new Pack.Sync(opt)
+  addFilesSync(p, files)
+  return p
+}
+
+const create = (opt, files) => {
+  const p = new Pack(opt)
+  addFilesAsync(p, files)
+  return p
+}
diff --git a/server/node_modules/tar/lib/extract.js b/server/node_modules/tar/lib/extract.js
new file mode 100644
index 0000000..5476798
--- /dev/null
+++ b/server/node_modules/tar/lib/extract.js
@@ -0,0 +1,113 @@
+'use strict'
+
+// tar -x
+const hlo = require('./high-level-opt.js')
+const Unpack = require('./unpack.js')
+const fs = require('fs')
+const fsm = require('fs-minipass')
+const path = require('path')
+const stripSlash = require('./strip-trailing-slashes.js')
+
+module.exports = (opt_, files, cb) => {
+  if (typeof opt_ === 'function') {
+    cb = opt_, files = null, opt_ = {}
+  } else if (Array.isArray(opt_)) {
+    files = opt_, opt_ = {}
+  }
+
+  if (typeof files === 'function') {
+    cb = files, files = null
+  }
+
+  if (!files) {
+    files = []
+  } else {
+    files = Array.from(files)
+  }
+
+  const opt = hlo(opt_)
+
+  if (opt.sync && typeof cb === 'function') {
+    throw new TypeError('callback not supported for sync tar functions')
+  }
+
+  if (!opt.file && typeof cb === 'function') {
+    throw new TypeError('callback only supported with file option')
+  }
+
+  if (files.length) {
+    filesFilter(opt, files)
+  }
+
+  return opt.file && opt.sync ? extractFileSync(opt)
+    : opt.file ? extractFile(opt, cb)
+    : opt.sync ? extractSync(opt)
+    : extract(opt)
+}
+
+// construct a filter that limits the file entries listed
+// include child entries if a dir is included
+const filesFilter = (opt, files) => {
+  const map = new Map(files.map(f => [stripSlash(f), true]))
+  const filter = opt.filter
+
+  const mapHas = (file, r) => {
+    const root = r || path.parse(file).root || '.'
+    const ret = file === root ? false
+      : map.has(file) ? map.get(file)
+      : mapHas(path.dirname(file), root)
+
+    map.set(file, ret)
+    return ret
+  }
+
+  opt.filter = filter
+    ? (file, entry) => filter(file, entry) && mapHas(stripSlash(file))
+    : file => mapHas(stripSlash(file))
+}
+
+const extractFileSync = opt => {
+  const u = new Unpack.Sync(opt)
+
+  const file = opt.file
+  const stat = fs.statSync(file)
+  // This trades a zero-byte read() syscall for a stat
+  // However, it will usually result in less memory allocation
+  const readSize = opt.maxReadSize || 16 * 1024 * 1024
+  const stream = new fsm.ReadStreamSync(file, {
+    readSize: readSize,
+    size: stat.size,
+  })
+  stream.pipe(u)
+}
+
+const extractFile = (opt, cb) => {
+  const u = new Unpack(opt)
+  const readSize = opt.maxReadSize || 16 * 1024 * 1024
+
+  const file = opt.file
+  const p = new Promise((resolve, reject) => {
+    u.on('error', reject)
+    u.on('close', resolve)
+
+    // This trades a zero-byte read() syscall for a stat
+    // However, it will usually result in less memory allocation
+    fs.stat(file, (er, stat) => {
+      if (er) {
+        reject(er)
+      } else {
+        const stream = new fsm.ReadStream(file, {
+          readSize: readSize,
+          size: stat.size,
+        })
+        stream.on('error', reject)
+        stream.pipe(u)
+      }
+    })
+  })
+  return cb ? p.then(cb, cb) : p
+}
+
+const extractSync = opt => new Unpack.Sync(opt)
+
+const extract = opt => new Unpack(opt)
diff --git a/server/node_modules/tar/lib/get-write-flag.js b/server/node_modules/tar/lib/get-write-flag.js
new file mode 100644
index 0000000..e869599
--- /dev/null
+++ b/server/node_modules/tar/lib/get-write-flag.js
@@ -0,0 +1,20 @@
+// Get the appropriate flag to use for creating files
+// We use fmap on Windows platforms for files less than
+// 512kb.  This is a fairly low limit, but avoids making
+// things slower in some cases.  Since most of what this
+// library is used for is extracting tarballs of many
+// relatively small files in npm packages and the like,
+// it can be a big boost on Windows platforms.
+// Only supported in Node v12.9.0 and above.
+const platform = process.env.__FAKE_PLATFORM__ || process.platform
+const isWindows = platform === 'win32'
+const fs = global.__FAKE_TESTING_FS__ || require('fs')
+
+/* istanbul ignore next */
+const { O_CREAT, O_TRUNC, O_WRONLY, UV_FS_O_FILEMAP = 0 } = fs.constants
+
+const fMapEnabled = isWindows && !!UV_FS_O_FILEMAP
+const fMapLimit = 512 * 1024
+const fMapFlag = UV_FS_O_FILEMAP | O_TRUNC | O_CREAT | O_WRONLY
+module.exports = !fMapEnabled ? () => 'w'
+  : size => size < fMapLimit ? fMapFlag : 'w'
diff --git a/server/node_modules/tar/lib/header.js b/server/node_modules/tar/lib/header.js
new file mode 100644
index 0000000..411d5e4
--- /dev/null
+++ b/server/node_modules/tar/lib/header.js
@@ -0,0 +1,304 @@
+'use strict'
+// parse a 512-byte header block to a data object, or vice-versa
+// encode returns `true` if a pax extended header is needed, because
+// the data could not be faithfully encoded in a simple header.
+// (Also, check header.needPax to see if it needs a pax header.)
+
+const types = require('./types.js')
+const pathModule = require('path').posix
+const large = require('./large-numbers.js')
+
+const SLURP = Symbol('slurp')
+const TYPE = Symbol('type')
+
+class Header {
+  constructor (data, off, ex, gex) {
+    this.cksumValid = false
+    this.needPax = false
+    this.nullBlock = false
+
+    this.block = null
+    this.path = null
+    this.mode = null
+    this.uid = null
+    this.gid = null
+    this.size = null
+    this.mtime = null
+    this.cksum = null
+    this[TYPE] = '0'
+    this.linkpath = null
+    this.uname = null
+    this.gname = null
+    this.devmaj = 0
+    this.devmin = 0
+    this.atime = null
+    this.ctime = null
+
+    if (Buffer.isBuffer(data)) {
+      this.decode(data, off || 0, ex, gex)
+    } else if (data) {
+      this.set(data)
+    }
+  }
+
+  decode (buf, off, ex, gex) {
+    if (!off) {
+      off = 0
+    }
+
+    if (!buf || !(buf.length >= off + 512)) {
+      throw new Error('need 512 bytes for header')
+    }
+
+    this.path = decString(buf, off, 100)
+    this.mode = decNumber(buf, off + 100, 8)
+    this.uid = decNumber(buf, off + 108, 8)
+    this.gid = decNumber(buf, off + 116, 8)
+    this.size = decNumber(buf, off + 124, 12)
+    this.mtime = decDate(buf, off + 136, 12)
+    this.cksum = decNumber(buf, off + 148, 12)
+
+    // if we have extended or global extended headers, apply them now
+    // See https://github.com/npm/node-tar/pull/187
+    this[SLURP](ex)
+    this[SLURP](gex, true)
+
+    // old tar versions marked dirs as a file with a trailing /
+    this[TYPE] = decString(buf, off + 156, 1)
+    if (this[TYPE] === '') {
+      this[TYPE] = '0'
+    }
+    if (this[TYPE] === '0' && this.path.slice(-1) === '/') {
+      this[TYPE] = '5'
+    }
+
+    // tar implementations sometimes incorrectly put the stat(dir).size
+    // as the size in the tarball, even though Directory entries are
+    // not able to have any body at all.  In the very rare chance that
+    // it actually DOES have a body, we weren't going to do anything with
+    // it anyway, and it'll just be a warning about an invalid header.
+    if (this[TYPE] === '5') {
+      this.size = 0
+    }
+
+    this.linkpath = decString(buf, off + 157, 100)
+    if (buf.slice(off + 257, off + 265).toString() === 'ustar\u000000') {
+      this.uname = decString(buf, off + 265, 32)
+      this.gname = decString(buf, off + 297, 32)
+      this.devmaj = decNumber(buf, off + 329, 8)
+      this.devmin = decNumber(buf, off + 337, 8)
+      if (buf[off + 475] !== 0) {
+        // definitely a prefix, definitely >130 chars.
+        const prefix = decString(buf, off + 345, 155)
+        this.path = prefix + '/' + this.path
+      } else {
+        const prefix = decString(buf, off + 345, 130)
+        if (prefix) {
+          this.path = prefix + '/' + this.path
+        }
+        this.atime = decDate(buf, off + 476, 12)
+        this.ctime = decDate(buf, off + 488, 12)
+      }
+    }
+
+    let sum = 8 * 0x20
+    for (let i = off; i < off + 148; i++) {
+      sum += buf[i]
+    }
+
+    for (let i = off + 156; i < off + 512; i++) {
+      sum += buf[i]
+    }
+
+    this.cksumValid = sum === this.cksum
+    if (this.cksum === null && sum === 8 * 0x20) {
+      this.nullBlock = true
+    }
+  }
+
+  [SLURP] (ex, global) {
+    for (const k in ex) {
+      // we slurp in everything except for the path attribute in
+      // a global extended header, because that's weird.
+      if (ex[k] !== null && ex[k] !== undefined &&
+          !(global && k === 'path')) {
+        this[k] = ex[k]
+      }
+    }
+  }
+
+  encode (buf, off) {
+    if (!buf) {
+      buf = this.block = Buffer.alloc(512)
+      off = 0
+    }
+
+    if (!off) {
+      off = 0
+    }
+
+    if (!(buf.length >= off + 512)) {
+      throw new Error('need 512 bytes for header')
+    }
+
+    const prefixSize = this.ctime || this.atime ? 130 : 155
+    const split = splitPrefix(this.path || '', prefixSize)
+    const path = split[0]
+    const prefix = split[1]
+    this.needPax = split[2]
+
+    this.needPax = encString(buf, off, 100, path) || this.needPax
+    this.needPax = encNumber(buf, off + 100, 8, this.mode) || this.needPax
+    this.needPax = encNumber(buf, off + 108, 8, this.uid) || this.needPax
+    this.needPax = encNumber(buf, off + 116, 8, this.gid) || this.needPax
+    this.needPax = encNumber(buf, off + 124, 12, this.size) || this.needPax
+    this.needPax = encDate(buf, off + 136, 12, this.mtime) || this.needPax
+    buf[off + 156] = this[TYPE].charCodeAt(0)
+    this.needPax = encString(buf, off + 157, 100, this.linkpath) || this.needPax
+    buf.write('ustar\u000000', off + 257, 8)
+    this.needPax = encString(buf, off + 265, 32, this.uname) || this.needPax
+    this.needPax = encString(buf, off + 297, 32, this.gname) || this.needPax
+    this.needPax = encNumber(buf, off + 329, 8, this.devmaj) || this.needPax
+    this.needPax = encNumber(buf, off + 337, 8, this.devmin) || this.needPax
+    this.needPax = encString(buf, off + 345, prefixSize, prefix) || this.needPax
+    if (buf[off + 475] !== 0) {
+      this.needPax = encString(buf, off + 345, 155, prefix) || this.needPax
+    } else {
+      this.needPax = encString(buf, off + 345, 130, prefix) || this.needPax
+      this.needPax = encDate(buf, off + 476, 12, this.atime) || this.needPax
+      this.needPax = encDate(buf, off + 488, 12, this.ctime) || this.needPax
+    }
+
+    let sum = 8 * 0x20
+    for (let i = off; i < off + 148; i++) {
+      sum += buf[i]
+    }
+
+    for (let i = off + 156; i < off + 512; i++) {
+      sum += buf[i]
+    }
+
+    this.cksum = sum
+    encNumber(buf, off + 148, 8, this.cksum)
+    this.cksumValid = true
+
+    return this.needPax
+  }
+
+  set (data) {
+    for (const i in data) {
+      if (data[i] !== null && data[i] !== undefined) {
+        this[i] = data[i]
+      }
+    }
+  }
+
+  get type () {
+    return types.name.get(this[TYPE]) || this[TYPE]
+  }
+
+  get typeKey () {
+    return this[TYPE]
+  }
+
+  set type (type) {
+    if (types.code.has(type)) {
+      this[TYPE] = types.code.get(type)
+    } else {
+      this[TYPE] = type
+    }
+  }
+}
+
+const splitPrefix = (p, prefixSize) => {
+  const pathSize = 100
+  let pp = p
+  let prefix = ''
+  let ret
+  const root = pathModule.parse(p).root || '.'
+
+  if (Buffer.byteLength(pp) < pathSize) {
+    ret = [pp, prefix, false]
+  } else {
+    // first set prefix to the dir, and path to the base
+    prefix = pathModule.dirname(pp)
+    pp = pathModule.basename(pp)
+
+    do {
+      if (Buffer.byteLength(pp) <= pathSize &&
+          Buffer.byteLength(prefix) <= prefixSize) {
+        // both fit!
+        ret = [pp, prefix, false]
+      } else if (Buffer.byteLength(pp) > pathSize &&
+          Buffer.byteLength(prefix) <= prefixSize) {
+        // prefix fits in prefix, but path doesn't fit in path
+        ret = [pp.slice(0, pathSize - 1), prefix, true]
+      } else {
+        // make path take a bit from prefix
+        pp = pathModule.join(pathModule.basename(prefix), pp)
+        prefix = pathModule.dirname(prefix)
+      }
+    } while (prefix !== root && !ret)
+
+    // at this point, found no resolution, just truncate
+    if (!ret) {
+      ret = [p.slice(0, pathSize - 1), '', true]
+    }
+  }
+  return ret
+}
+
+const decString = (buf, off, size) =>
+  buf.slice(off, off + size).toString('utf8').replace(/\0.*/, '')
+
+const decDate = (buf, off, size) =>
+  numToDate(decNumber(buf, off, size))
+
+const numToDate = num => num === null ? null : new Date(num * 1000)
+
+const decNumber = (buf, off, size) =>
+  buf[off] & 0x80 ? large.parse(buf.slice(off, off + size))
+  : decSmallNumber(buf, off, size)
+
+const nanNull = value => isNaN(value) ? null : value
+
+const decSmallNumber = (buf, off, size) =>
+  nanNull(parseInt(
+    buf.slice(off, off + size)
+      .toString('utf8').replace(/\0.*$/, '').trim(), 8))
+
+// the maximum encodable as a null-terminated octal, by field size
+const MAXNUM = {
+  12: 0o77777777777,
+  8: 0o7777777,
+}
+
+const encNumber = (buf, off, size, number) =>
+  number === null ? false :
+  number > MAXNUM[size] || number < 0
+    ? (large.encode(number, buf.slice(off, off + size)), true)
+    : (encSmallNumber(buf, off, size, number), false)
+
+const encSmallNumber = (buf, off, size, number) =>
+  buf.write(octalString(number, size), off, size, 'ascii')
+
+const octalString = (number, size) =>
+  padOctal(Math.floor(number).toString(8), size)
+
+const padOctal = (string, size) =>
+  (string.length === size - 1 ? string
+  : new Array(size - string.length - 1).join('0') + string + ' ') + '\0'
+
+const encDate = (buf, off, size, date) =>
+  date === null ? false :
+  encNumber(buf, off, size, date.getTime() / 1000)
+
+// enough to fill the longest string we've got
+const NULLS = new Array(156).join('\0')
+// pad with nulls, return true if it's longer or non-ascii
+const encString = (buf, off, size, string) =>
+  string === null ? false :
+  (buf.write(string + NULLS, off, size, 'utf8'),
+  string.length !== Buffer.byteLength(string) || string.length > size)
+
+module.exports = Header
diff --git a/server/node_modules/tar/lib/high-level-opt.js b/server/node_modules/tar/lib/high-level-opt.js
new file mode 100644
index 0000000..40e4418
--- /dev/null
+++ b/server/node_modules/tar/lib/high-level-opt.js
@@ -0,0 +1,29 @@
+'use strict'
+
+// turn tar(1) style args like `C` into the more verbose things like `cwd`
+
+const argmap = new Map([
+  ['C', 'cwd'],
+  ['f', 'file'],
+  ['z', 'gzip'],
+  ['P', 'preservePaths'],
+  ['U', 'unlink'],
+  ['strip-components', 'strip'],
+  ['stripComponents', 'strip'],
+  ['keep-newer', 'newer'],
+  ['keepNewer', 'newer'],
+  ['keep-newer-files', 'newer'],
+  ['keepNewerFiles', 'newer'],
+  ['k', 'keep'],
+  ['keep-existing', 'keep'],
+  ['keepExisting', 'keep'],
+  ['m', 'noMtime'],
+  ['no-mtime', 'noMtime'],
+  ['p', 'preserveOwner'],
+  ['L', 'follow'],
+  ['h', 'follow'],
+])
+
+module.exports = opt => opt ? Object.keys(opt).map(k => [
+  argmap.has(k) ? argmap.get(k) : k, opt[k],
+]).reduce((set, kv) => (set[kv[0]] = kv[1], set), Object.create(null)) : {}
diff --git a/server/node_modules/tar/lib/large-numbers.js b/server/node_modules/tar/lib/large-numbers.js
new file mode 100644
index 0000000..b11e72d
--- /dev/null
+++ b/server/node_modules/tar/lib/large-numbers.js
@@ -0,0 +1,104 @@
+'use strict'
+// Tar can encode large and negative numbers using a leading byte of
+// 0xff for negative, and 0x80 for positive.
+
+const encode = (num, buf) => {
+  if (!Number.isSafeInteger(num)) {
+  // The number is so large that javascript cannot represent it with integer
+  // precision.
+    throw Error('cannot encode number outside of javascript safe integer range')
+  } else if (num < 0) {
+    encodeNegative(num, buf)
+  } else {
+    encodePositive(num, buf)
+  }
+  return buf
+}
+
+const encodePositive = (num, buf) => {
+  buf[0] = 0x80
+
+  for (var i = buf.length; i > 1; i--) {
+    buf[i - 1] = num & 0xff
+    num = Math.floor(num / 0x100)
+  }
+}
+
+const encodeNegative = (num, buf) => {
+  buf[0] = 0xff
+  var flipped = false
+  num = num * -1
+  for (var i = buf.length; i > 1; i--) {
+    var byte = num & 0xff
+    num = Math.floor(num / 0x100)
+    if (flipped) {
+      buf[i - 1] = onesComp(byte)
+    } else if (byte === 0) {
+      buf[i - 1] = 0
+    } else {
+      flipped = true
+      buf[i - 1] = twosComp(byte)
+    }
+  }
+}
+
+const parse = (buf) => {
+  const pre = buf[0]
+  const value = pre === 0x80 ? pos(buf.slice(1, buf.length))
+    : pre === 0xff ? twos(buf)
+    : null
+  if (value === null) {
+    throw Error('invalid base256 encoding')
+  }
+
+  if (!Number.isSafeInteger(value)) {
+  // The number is so large that javascript cannot represent it with integer
+  // precision.
+    throw Error('parsed number outside of javascript safe integer range')
+  }
+
+  return value
+}
+
+const twos = (buf) => {
+  var len = buf.length
+  var sum = 0
+  var flipped = false
+  for (var i = len - 1; i > -1; i--) {
+    var byte = buf[i]
+    var f
+    if (flipped) {
+      f = onesComp(byte)
+    } else if (byte === 0) {
+      f = byte
+    } else {
+      flipped = true
+      f = twosComp(byte)
+    }
+    if (f !== 0) {
+      sum -= f * Math.pow(256, len - i - 1)
+    }
+  }
+  return sum
+}
+
+const pos = (buf) => {
+  var len = buf.length
+  var sum = 0
+  for (var i = len - 1; i > -1; i--) {
+    var byte = buf[i]
+    if (byte !== 0) {
+      sum += byte * Math.pow(256, len - i - 1)
+    }
+  }
+  return sum
+}
+
+const onesComp = byte => (0xff ^ byte) & 0xff
+
+const twosComp = byte => ((0xff ^ byte) + 1) & 0xff
+
+module.exports = {
+  encode,
+  parse,
+}
diff --git a/server/node_modules/tar/lib/list.js b/server/node_modules/tar/lib/list.js
new file mode 100644
index 0000000..f2358c2
--- /dev/null
+++ b/server/node_modules/tar/lib/list.js
@@ -0,0 +1,139 @@
+'use strict'
+
+// XXX: This shares a lot in common with extract.js
+// maybe some DRY opportunity here?
+
+// tar -t
+const hlo = require('./high-level-opt.js')
+const Parser = require('./parse.js')
+const fs = require('fs')
+const fsm = require('fs-minipass')
+const path = require('path')
+const stripSlash = require('./strip-trailing-slashes.js')
+
+module.exports = (opt_, files, cb) => {
+  if (typeof opt_ === 'function') {
+    cb = opt_, files = null, opt_ = {}
+  } else if (Array.isArray(opt_)) {
+    files = opt_, opt_ = {}
+  }
+
+  if (typeof files === 'function') {
+    cb = files, files = null
+  }
+
+  if (!files) {
+    files = []
+  } else {
+    files = Array.from(files)
+  }
+
+  const opt = hlo(opt_)
+
+  if (opt.sync && typeof cb === 'function') {
+    throw new TypeError('callback not supported for sync tar functions')
+  }
+
+  if (!opt.file && typeof cb === 'function') {
+    throw new TypeError('callback only supported with file option')
+  }
+
+  if (files.length) {
+    filesFilter(opt, files)
+  }
+
+  if (!opt.noResume) {
+    onentryFunction(opt)
+  }
+
+  return opt.file && opt.sync ? listFileSync(opt)
+    : opt.file ? listFile(opt, cb)
+    : list(opt)
+}
+
+const onentryFunction = opt => {
+  const onentry = opt.onentry
+  opt.onentry = onentry ? e => {
+    onentry(e)
+    e.resume()
+  } : e => e.resume()
+}
+
+// construct a filter that limits the file entries listed
+// include child entries if a dir is included
+const filesFilter = (opt, files) => {
+  const map = new Map(files.map(f => [stripSlash(f), true]))
+  const filter = opt.filter
+
+  const mapHas = (file, r) => {
+    const root = r || path.parse(file).root || '.'
+    const ret = file === root ? false
+      : map.has(file) ? map.get(file)
+      : mapHas(path.dirname(file), root)
+
+    map.set(file, ret)
+    return ret
+  }
+
+  opt.filter = filter
+    ? (file, entry) => filter(file, entry) && mapHas(stripSlash(file))
+    : file => mapHas(stripSlash(file))
+}
+
+const listFileSync = opt => {
+  const p = list(opt)
+  const file = opt.file
+  let threw = true
+  let fd
+  try {
+    const stat = fs.statSync(file)
+    const readSize = opt.maxReadSize || 16 * 1024 * 1024
+    if (stat.size < readSize) {
+      p.end(fs.readFileSync(file))
+    } else {
+      let pos = 0
+      const buf = Buffer.allocUnsafe(readSize)
+      fd = fs.openSync(file, 'r')
+      while (pos < stat.size) {
+        const bytesRead = fs.readSync(fd, buf, 0, readSize, pos)
+        pos += bytesRead
+        p.write(buf.slice(0, bytesRead))
+      }
+      p.end()
+    }
+    threw = false
+  } finally {
+    if (threw && fd) {
+      try {
+        fs.closeSync(fd)
+      } catch (er) {}
+    }
+  }
+}
+
+const listFile = (opt, cb) => {
+  const parse = new Parser(opt)
+  const readSize = opt.maxReadSize || 16 * 1024 * 1024
+
+  const file = opt.file
+  const p = new Promise((resolve, reject) => {
+    parse.on('error', reject)
+    parse.on('end', resolve)
+
+    fs.stat(file, (er, stat) => {
+      if (er) {
+        reject(er)
+      } else {
+        const stream = new fsm.ReadStream(file, {
+          readSize: readSize,
+          size: stat.size,
+        })
+        stream.on('error', reject)
+        stream.pipe(parse)
+      }
+    })
+  })
+  return cb ? p.then(cb, cb) : p
+}
+
+const list = opt => new Parser(opt)
diff --git a/server/node_modules/tar/lib/mkdir.js b/server/node_modules/tar/lib/mkdir.js
new file mode 100644
index 0000000..8ee8de7
--- /dev/null
+++ b/server/node_modules/tar/lib/mkdir.js
@@ -0,0 +1,229 @@
+'use strict'
+// wrapper around mkdirp for tar's needs.
+
+// TODO: This should probably be a class, not functionally
+// passing around state in a gazillion args.
+
+const mkdirp = require('mkdirp')
+const fs = require('fs')
+const path = require('path')
+const chownr = require('chownr')
+const normPath = require('./normalize-windows-path.js')
+
+class SymlinkError extends Error {
+  constructor (symlink, path) {
+    super('Cannot extract through symbolic link')
+    this.path = path
+    this.symlink = symlink
+  }
+
+  get name () {
+    return 'SylinkError'
+  }
+}
+
+class CwdError extends Error {
+  constructor (path, code) {
+    super(code + ': Cannot cd into \'' + path + '\'')
+    this.path = path
+    this.code = code
+  }
+
+  get name () {
+    return 'CwdError'
+  }
+}
+
+const cGet = (cache, key) => cache.get(normPath(key))
+const cSet = (cache, key, val) => cache.set(normPath(key), val)
+
+const checkCwd = (dir, cb) => {
+  fs.stat(dir, (er, st) => {
+    if (er || !st.isDirectory()) {
+      er = new CwdError(dir, er && er.code || 'ENOTDIR')
+    }
+    cb(er)
+  })
+}
+
+module.exports = (dir, opt, cb) => {
+  dir = normPath(dir)
+
+  // if there's any overlap between mask and mode,
+  // then we'll need an explicit chmod
+  const umask = opt.umask
+  const mode = opt.mode | 0o0700
+  const needChmod = (mode & umask) !== 0
+
+  const uid = opt.uid
+  const gid = opt.gid
+  const doChown = typeof uid === 'number' &&
+    typeof gid === 'number' &&
+    (uid !== opt.processUid || gid !== opt.processGid)
+
+  const preserve = opt.preserve
+  const unlink = opt.unlink
+  const cache = opt.cache
+  const cwd = normPath(opt.cwd)
+
+  const done = (er, created) => {
+    if (er) {
+      cb(er)
+    } else {
+      cSet(cache, dir, true)
+      if (created && doChown) {
+        chownr(created, uid, gid, er => done(er))
+      } else if (needChmod) {
+        fs.chmod(dir, mode, cb)
+      } else {
+        cb()
+      }
+    }
+  }
+
+  if (cache && cGet(cache, dir) === true) {
+    return done()
+  }
+
+  if (dir === cwd) {
+    return checkCwd(dir, done)
+  }
+
+  if (preserve) {
+    return mkdirp(dir, { mode }).then(made => done(null, made), done)
+  }
+
+  const sub = normPath(path.relative(cwd, dir))
+  const parts = sub.split('/')
+  mkdir_(cwd, parts, mode, cache, unlink, cwd, null, done)
+}
+
+const mkdir_ = (base, parts, mode, cache, unlink, cwd, created, cb) => {
+  if (!parts.length) {
+    return cb(null, created)
+  }
+  const p = parts.shift()
+  const part = normPath(path.resolve(base + '/' + p))
+  if (cGet(cache, part)) {
+    return mkdir_(part, parts, mode, cache, unlink, cwd, created, cb)
+  }
+  fs.mkdir(part, mode, onmkdir(part, parts, mode, cache, unlink, cwd, created, cb))
+}
+
+const onmkdir = (part, parts, mode, cache, unlink, cwd, created, cb) => er => {
+  if (er) {
+    fs.lstat(part, (statEr, st) => {
+      if (statEr) {
+        statEr.path = statEr.path && normPath(statEr.path)
+        cb(statEr)
+      } else if (st.isDirectory()) {
+        mkdir_(part, parts, mode, cache, unlink, cwd, created, cb)
+      } else if (unlink) {
+        fs.unlink(part, er => {
+          if (er) {
+            return cb(er)
+          }
+          fs.mkdir(part, mode, onmkdir(part, parts, mode, cache, unlink, cwd, created, cb))
+        })
+      } else if (st.isSymbolicLink()) {
+        return cb(new SymlinkError(part, part + '/' + parts.join('/')))
+      } else {
+        cb(er)
+      }
+    })
+  } else {
+    created = created || part
+    mkdir_(part, parts, mode, cache, unlink, cwd, created, cb)
+  }
+}
+
+const checkCwdSync = dir => {
+  let ok = false
+  let code = 'ENOTDIR'
+  try {
+    ok = fs.statSync(dir).isDirectory()
+  } catch (er) {
+    code = er.code
+  } finally {
+    if (!ok) {
+      throw new CwdError(dir, code)
+    }
+  }
+}
+
+module.exports.sync = (dir, opt) => {
+  dir = normPath(dir)
+  // if there's any overlap between mask and mode,
+  // then we'll need an explicit chmod
+  const umask = opt.umask
+  const mode = opt.mode | 0o0700
+  const needChmod = (mode & umask) !== 0
+
+  const uid = opt.uid
+  const gid = opt.gid
+  const doChown = typeof uid === 'number' &&
+    typeof gid === 'number' &&
+    (uid !== opt.processUid || gid !== opt.processGid)
+
+  const preserve = opt.preserve
+  const unlink = opt.unlink
+  const cache = opt.cache
+  const cwd = normPath(opt.cwd)
+
+  const done = (created) => {
+    cSet(cache, dir, true)
+    if (created && doChown) {
+      chownr.sync(created, uid, gid)
+    }
+    if (needChmod) {
+      fs.chmodSync(dir, mode)
+    }
+  }
+
+  if (cache && cGet(cache, dir) === true) {
+    return done()
+  }
+
+  if (dir === cwd) {
+    checkCwdSync(cwd)
+    return done()
+  }
+
+  if (preserve) {
+    return done(mkdirp.sync(dir, mode))
+  }
+
+  const sub = normPath(path.relative(cwd, dir))
+  const parts = sub.split('/')
+  let created = null
+  for (let p = parts.shift(), part = cwd;
+    p && (part += '/' + p);
+    p = parts.shift()) {
+    part = normPath(path.resolve(part))
+    if (cGet(cache, part)) {
+      continue
+    }
+
+    try {
+      fs.mkdirSync(part, mode)
+      created = created || part
+      cSet(cache, part, true)
+    } catch (er) {
+      const st = fs.lstatSync(part)
+      if (st.isDirectory()) {
+        cSet(cache, part, true)
+        continue
+      } else if (unlink) {
+        fs.unlinkSync(part)
+        fs.mkdirSync(part, mode)
+        created = created || part
+        cSet(cache, part, true)
+        continue
+      } else if (st.isSymbolicLink()) {
+        return new SymlinkError(part, part + '/' + parts.join('/'))
+      }
+    }
+  }
+
+  return done(created)
+}
diff --git a/server/node_modules/tar/lib/mode-fix.js b/server/node_modules/tar/lib/mode-fix.js
new file mode 100644
index 0000000..42f1d6e
--- /dev/null
+++ b/server/node_modules/tar/lib/mode-fix.js
@@ -0,0 +1,27 @@
+'use strict'
+module.exports = (mode, isDir, portable) => {
+  mode &= 0o7777
+
+  // in portable mode, use the minimum reasonable umask
+  // if this system creates files with 0o664 by default
+  // (as some linux distros do), then we'll write the
+  // archive with 0o644 instead.  Also, don't ever create
+  // a file that is not readable/writable by the owner.
+  if (portable) {
+    mode = (mode | 0o600) & ~0o22
+  }
+
+  // if dirs are readable, then they should be listable
+  if (isDir) {
+    if (mode & 0o400) {
+      mode |= 0o100
+    }
+    if (mode & 0o40) {
+      mode |= 0o10
+    }
+    if (mode & 0o4) {
+      mode |= 0o1
+    }
+  }
+  return mode
+}
diff --git a/server/node_modules/tar/lib/normalize-unicode.js b/server/node_modules/tar/lib/normalize-unicode.js
new file mode 100644
index 0000000..79e285a
--- /dev/null
+++ b/server/node_modules/tar/lib/normalize-unicode.js
@@ -0,0 +1,12 @@
+// warning: extremely hot code path.
+// This has been meticulously optimized for use
+// within npm install on large package trees.
+// Do not edit without careful benchmarking.
+const normalizeCache = Object.create(null)
+const { hasOwnProperty } = Object.prototype
+module.exports = s => {
+  if (!hasOwnProperty.call(normalizeCache, s)) {
+    normalizeCache[s] = s.normalize('NFD')
+  }
+  return normalizeCache[s]
+}
diff --git a/server/node_modules/tar/lib/normalize-windows-path.js b/server/node_modules/tar/lib/normalize-windows-path.js
new file mode 100644
index 0000000..eb13ba0
--- /dev/null
+++ b/server/node_modules/tar/lib/normalize-windows-path.js
@@ -0,0 +1,8 @@
+// on windows, either \ or / are valid directory separators.
+// on unix, \ is a valid character in filenames.
+// so, on windows, and only on windows, we replace all \ chars with /,
+// so that we can use / as our one and only directory separator char.
+
+const platform = process.env.TESTING_TAR_FAKE_PLATFORM || process.platform
+module.exports = platform !== 'win32' ? p => p
+  : p => p && p.replace(/\\/g, '/')
diff --git a/server/node_modules/tar/lib/pack.js b/server/node_modules/tar/lib/pack.js
new file mode 100644
index 0000000..d533a06
--- /dev/null
+++ b/server/node_modules/tar/lib/pack.js
@@ -0,0 +1,432 @@
+'use strict'
+
+// A readable tar stream creator
+// Technically, this is a transform stream that you write paths into,
+// and tar format comes out of.
+// The `add()` method is like `write()` but returns this,
+// and end() return `this` as well, so you can
+// do `new Pack(opt).add('files').add('dir').end().pipe(output)
+// You could also do something like:
+// streamOfPaths().pipe(new Pack()).pipe(new fs.WriteStream('out.tar'))
+
+class PackJob {
+  constructor (path, absolute) {
+    this.path = path || './'
+    this.absolute = absolute
+    this.entry = null
+    this.stat = null
+    this.readdir = null
+    this.pending = false
+    this.ignore = false
+    this.piped = false
+  }
+}
+
+const { Minipass } = require('minipass')
+const zlib = require('minizlib')
+const ReadEntry = require('./read-entry.js')
+const WriteEntry = require('./write-entry.js')
+const WriteEntrySync = WriteEntry.Sync
+const WriteEntryTar = WriteEntry.Tar
+const Yallist = require('yallist')
+const EOF = Buffer.alloc(1024)
+const ONSTAT = Symbol('onStat')
+const ENDED = Symbol('ended')
+const QUEUE = Symbol('queue')
+const CURRENT = Symbol('current')
+const PROCESS = Symbol('process')
+const PROCESSING = Symbol('processing')
+const PROCESSJOB = Symbol('processJob')
+const JOBS = Symbol('jobs')
+const JOBDONE = Symbol('jobDone')
+const ADDFSENTRY = Symbol('addFSEntry')
+const ADDTARENTRY = Symbol('addTarEntry')
+const STAT = Symbol('stat')
+const READDIR = Symbol('readdir')
+const ONREADDIR = Symbol('onreaddir')
+const PIPE = Symbol('pipe')
+const ENTRY = Symbol('entry')
+const ENTRYOPT = Symbol('entryOpt')
+const WRITEENTRYCLASS = Symbol('writeEntryClass')
+const WRITE = Symbol('write')
+const ONDRAIN = Symbol('ondrain')
+
+const fs = require('fs')
+const path = require('path')
+const warner = require('./warn-mixin.js')
+const normPath = require('./normalize-windows-path.js')
+
+const Pack = warner(class Pack extends Minipass {
+  constructor (opt) {
+    super(opt)
+    opt = opt || Object.create(null)
+    this.opt = opt
+    this.file = opt.file || ''
+    this.cwd = opt.cwd || process.cwd()
+    this.maxReadSize = opt.maxReadSize
+    this.preservePaths = !!opt.preservePaths
+    this.strict = !!opt.strict
+    this.noPax = !!opt.noPax
+    this.prefix = normPath(opt.prefix || '')
+    this.linkCache = opt.linkCache || new Map()
+    this.statCache = opt.statCache || new Map()
+    this.readdirCache = opt.readdirCache || new Map()
+
+    this[WRITEENTRYCLASS] = WriteEntry
+    if (typeof opt.onwarn === 'function') {
+      this.on('warn', opt.onwarn)
+    }
+
+    this.portable = !!opt.portable
+    this.zip = null
+
+    if (opt.gzip || opt.brotli) {
+      if (opt.gzip && opt.brotli) {
+        throw new TypeError('gzip and brotli are mutually exclusive')
+      }
+      if (opt.gzip) {
+        if (typeof opt.gzip !== 'object') {
+          opt.gzip = {}
+        }
+        if (this.portable) {
+          opt.gzip.portable = true
+        }
+        this.zip = new zlib.Gzip(opt.gzip)
+      }
+      if (opt.brotli) {
+        if (typeof opt.brotli !== 'object') {
+          opt.brotli = {}
+        }
+        this.zip = new zlib.BrotliCompress(opt.brotli)
+      }
+      this.zip.on('data', chunk => super.write(chunk))
+      this.zip.on('end', _ => super.end())
+      this.zip.on('drain', _ => this[ONDRAIN]())
+      this.on('resume', _ => this.zip.resume())
+    } else {
+      this.on('drain', this[ONDRAIN])
+    }
+
+    this.noDirRecurse = !!opt.noDirRecurse
+    this.follow = !!opt.follow
+    this.noMtime = !!opt.noMtime
+    this.mtime = opt.mtime || null
+
+    this.filter = typeof opt.filter === 'function' ? opt.filter : _ => true
+
+    this[QUEUE] = new Yallist()
+    this[JOBS] = 0
+    this.jobs = +opt.jobs || 4
+    this[PROCESSING] = false
+    this[ENDED] = false
+  }
+
+  [WRITE] (chunk) {
+    return super.write(chunk)
+  }
+
+  add (path) {
+    this.write(path)
+    return this
+  }
+
+  end (path) {
+    if (path) {
+      this.write(path)
+    }
+    this[ENDED] = true
+    this[PROCESS]()
+    return this
+  }
+
+  write (path) {
+    if (this[ENDED]) {
+      throw new Error('write after end')
+    }
+
+    if (path instanceof ReadEntry) {
+      this[ADDTARENTRY](path)
+    } else {
+      this[ADDFSENTRY](path)
+    }
+    return this.flowing
+  }
+
+  [ADDTARENTRY] (p) {
+    const absolute = normPath(path.resolve(this.cwd, p.path))
+    // in this case, we don't have to wait for the stat
+    if (!this.filter(p.path, p)) {
+      p.resume()
+    } else {
+      const job = new PackJob(p.path, absolute, false)
+      job.entry = new WriteEntryTar(p, this[ENTRYOPT](job))
+      job.entry.on('end', _ => this[JOBDONE](job))
+      this[JOBS] += 1
+      this[QUEUE].push(job)
+    }
+
+    this[PROCESS]()
+  }
+
+  [ADDFSENTRY] (p) {
+    const absolute = normPath(path.resolve(this.cwd, p))
+    this[QUEUE].push(new PackJob(p, absolute))
+    this[PROCESS]()
+  }
+
+  [STAT] (job) {
+    job.pending = true
+    this[JOBS] += 1
+    const stat = this.follow ? 'stat' : 'lstat'
+    fs[stat](job.absolute, (er, stat) => {
+      job.pending = false
+      this[JOBS] -= 1
+      if (er) {
+        this.emit('error', er)
+      } else {
+        this[ONSTAT](job, stat)
+      }
+    })
+  }
+
+  [ONSTAT] (job, stat) {
+    this.statCache.set(job.absolute, stat)
+    job.stat = stat
+
+    // now we have the stat, we can filter it.
+    if (!this.filter(job.path, stat)) {
+      job.ignore = true
+    }
+
+    this[PROCESS]()
+  }
+
+  [READDIR] (job) {
+    job.pending = true
+    this[JOBS] += 1
+    fs.readdir(job.absolute, (er, entries) => {
+      job.pending = false
+      this[JOBS] -= 1
+      if (er) {
+        return this.emit('error', er)
+      }
+      this[ONREADDIR](job, entries)
+    })
+  }
+
+  [ONREADDIR] (job, entries) {
+    this.readdirCache.set(job.absolute, entries)
+    job.readdir = entries
+    this[PROCESS]()
+  }
+
+  [PROCESS] () {
+    if (this[PROCESSING]) {
+      return
+    }
+
+    this[PROCESSING] = true
+    for (let w = this[QUEUE].head;
+      w !== null && this[JOBS] < this.jobs;
+      w = w.next) {
+      this[PROCESSJOB](w.value)
+      if (w.value.ignore) {
+        const p = w.next
+        this[QUEUE].removeNode(w)
+        w.next = p
+      }
+    }
+
+    this[PROCESSING] = false
+
+    if (this[ENDED] && !this[QUEUE].length && this[JOBS] === 0) {
+      if (this.zip) {
+        this.zip.end(EOF)
+      } else {
+        super.write(EOF)
+        super.end()
+      }
+    }
+  }
+
+  get [CURRENT] () {
+    return this[QUEUE] && this[QUEUE].head && this[QUEUE].head.value
+  }
+
+  [JOBDONE] (job) {
+    this[QUEUE].shift()
+    this[JOBS] -= 1
+    this[PROCESS]()
+  }
+
+  [PROCESSJOB] (job) {
+    if (job.pending) {
+      return
+    }
+
+    if (job.entry) {
+      if (job === this[CURRENT] && !job.piped) {
+        this[PIPE](job)
+      }
+      return
+    }
+
+    if (!job.stat) {
+      if (this.statCache.has(job.absolute)) {
+        this[ONSTAT](job, this.statCache.get(job.absolute))
+      } else {
+        this[STAT](job)
+      }
+    }
+    if (!job.stat) {
+      return
+    }
+
+    // filtered out!
+    if (job.ignore) {
+      return
+    }
+
+    if (!this.noDirRecurse && job.stat.isDirectory() && !job.readdir) {
+      if (this.readdirCache.has(job.absolute)) {
+        this[ONREADDIR](job, this.readdirCache.get(job.absolute))
+      } else {
+        this[READDIR](job)
+      }
+      if (!job.readdir) {
+        return
+      }
+    }
+
+    // we know it doesn't have an entry, because that got checked above
+    job.entry = this[ENTRY](job)
+    if (!job.entry) {
+      job.ignore = true
+      return
+    }
+
+    if (job === this[CURRENT] && !job.piped) {
+      this[PIPE](job)
+    }
+  }
+
+  [ENTRYOPT] (job) {
+    return {
+      onwarn: (code, msg, data) => this.warn(code, msg, data),
+      noPax: this.noPax,
+      cwd: this.cwd,
+      absolute: job.absolute,
+      preservePaths: this.preservePaths,
+      maxReadSize: this.maxReadSize,
+      strict: this.strict,
+      portable: this.portable,
+      linkCache: this.linkCache,
+      statCache: this.statCache,
+      noMtime: this.noMtime,
+      mtime: this.mtime,
+      prefix: this.prefix,
+    }
+  }
+
+  [ENTRY] (job) {
+    this[JOBS] += 1
+    try {
+      return new this[WRITEENTRYCLASS](job.path, this[ENTRYOPT](job))
+        .on('end', () => this[JOBDONE](job))
+        .on('error', er => this.emit('error', er))
+    } catch (er) {
+      this.emit('error', er)
+    }
+  }
+
+  [ONDRAIN] () {
+    if (this[CURRENT] && this[CURRENT].entry) {
+      this[CURRENT].entry.resume()
+    }
+  }
+
+  // like .pipe() but using super, because our write() is special
+  [PIPE] (job) {
+    job.piped = true
+
+    if (job.readdir) {
+      job.readdir.forEach(entry => {
+        const p = job.path
+        const base = p === './' ? '' : p.replace(/\/*$/, '/')
+        this[ADDFSENTRY](base + entry)
+      })
+    }
+
+    const source = job.entry
+    const zip = this.zip
+
+    if (zip) {
+      source.on('data', chunk => {
+        if (!zip.write(chunk)) {
+          source.pause()
+        }
+      })
+    } else {
+      source.on('data', chunk => {
+        if (!super.write(chunk)) {
+          source.pause()
+        }
+      })
+    }
+  }
+
+  pause () {
+    if (this.zip) {
+      this.zip.pause()
+    }
+    return super.pause()
+  }
+})
+
+class PackSync extends Pack {
+  constructor (opt) {
+    super(opt)
+    this[WRITEENTRYCLASS] = WriteEntrySync
+  }
+
+  // pause/resume are no-ops in sync streams.
+  pause () {}
+  resume () {}
+
+  [STAT] (job) {
+    const stat = this.follow ? 'statSync' : 'lstatSync'
+    this[ONSTAT](job, fs[stat](job.absolute))
+  }
+
+  [READDIR] (job, stat) {
+    this[ONREADDIR](job, fs.readdirSync(job.absolute))
+  }
+
+  // gotta get it all in this tick
+  [PIPE] (job) {
+    const source = job.entry
+    const zip = this.zip
+
+    if (job.readdir) {
+      job.readdir.forEach(entry => {
+        const p = job.path
+        const base = p === './' ? '' : p.replace(/\/*$/, '/')
+        this[ADDFSENTRY](base + entry)
+      })
+    }
+
+    if (zip) {
+      source.on('data', chunk => {
+        zip.write(chunk)
+      })
+    } else {
+      source.on('data', chunk => {
+        super[WRITE](chunk)
+      })
+    }
+  }
+}
+
+Pack.Sync = PackSync
+
+module.exports = Pack
diff --git a/server/node_modules/tar/lib/parse.js b/server/node_modules/tar/lib/parse.js
new file mode 100644
index 0000000..94e5304
--- /dev/null
+++ b/server/node_modules/tar/lib/parse.js
@@ -0,0 +1,552 @@
+'use strict'
+
+// this[BUFFER] is the remainder of a chunk if we're waiting for
+// the full 512 bytes of a header to come in.  We will Buffer.concat()
+// it to the next write(), which is a mem copy, but a small one.
+//
+// this[QUEUE] is a Yallist of entries that haven't been emitted
+// yet this can only get filled up if the user keeps write()ing after
+// a write() returns false, or does a write() with more than one entry
+//
+// We don't buffer chunks, we always parse them and either create an
+// entry, or push it into the active entry.  The ReadEntry class knows
+// to throw data away if .ignore=true
+//
+// Shift entry off the buffer when it emits 'end', and emit 'entry' for
+// the next one in the list.
+//
+// At any time, we're pushing body chunks into the entry at WRITEENTRY,
+// and waiting for 'end' on the entry at READENTRY
+//
+// ignored entries get .resume() called on them straight away
+
+const warner = require('./warn-mixin.js')
+const Header = require('./header.js')
+const EE = require('events')
+const Yallist = require('yallist')
+const maxMetaEntrySize = 1024 * 1024
+const Entry = require('./read-entry.js')
+const Pax = require('./pax.js')
+const zlib = require('minizlib')
+const { nextTick } = require('process')
+
+const gzipHeader = Buffer.from([0x1f, 0x8b])
+const STATE = Symbol('state')
+const WRITEENTRY = Symbol('writeEntry')
+const READENTRY = Symbol('readEntry')
+const NEXTENTRY = Symbol('nextEntry')
+const PROCESSENTRY = Symbol('processEntry')
+const EX = Symbol('extendedHeader')
+const GEX = Symbol('globalExtendedHeader')
+const META = Symbol('meta')
+const EMITMETA = Symbol('emitMeta')
+const BUFFER = Symbol('buffer')
+const QUEUE = Symbol('queue')
+const ENDED = Symbol('ended')
+const EMITTEDEND = Symbol('emittedEnd')
+const EMIT = Symbol('emit')
+const UNZIP = Symbol('unzip')
+const CONSUMECHUNK = Symbol('consumeChunk')
+const CONSUMECHUNKSUB = Symbol('consumeChunkSub')
+const CONSUMEBODY = Symbol('consumeBody')
+const CONSUMEMETA = Symbol('consumeMeta')
+const CONSUMEHEADER = Symbol('consumeHeader')
+const CONSUMING = Symbol('consuming')
+const BUFFERCONCAT = Symbol('bufferConcat')
+const MAYBEEND = Symbol('maybeEnd')
+const WRITING = Symbol('writing')
+const ABORTED = Symbol('aborted')
+const DONE = Symbol('onDone')
+const SAW_VALID_ENTRY = Symbol('sawValidEntry')
+const SAW_NULL_BLOCK = Symbol('sawNullBlock')
+const SAW_EOF = Symbol('sawEOF')
+const CLOSESTREAM = Symbol('closeStream')
+
+const noop = _ => true
+
+module.exports = warner(class Parser extends EE {
+  constructor (opt) {
+    opt = opt || {}
+    super(opt)
+
+    this.file = opt.file || ''
+
+    // set to boolean false when an entry starts.  1024 bytes of \0
+    // is technically a valid tarball, albeit a boring one.
+    this[SAW_VALID_ENTRY] = null
+
+    // these BADARCHIVE errors can't be detected early. listen on DONE.
+    this.on(DONE, _ => {
+      if (this[STATE] === 'begin' || this[SAW_VALID_ENTRY] === false) {
+        // either less than 1 block of data, or all entries were invalid.
+        // Either way, probably not even a tarball.
+        this.warn('TAR_BAD_ARCHIVE', 'Unrecognized archive format')
+      }
+    })
+
+    if (opt.ondone) {
+      this.on(DONE, opt.ondone)
+    } else {
+      this.on(DONE, _ => {
+        this.emit('prefinish')
+        this.emit('finish')
+        this.emit('end')
+      })
+    }
+
+    this.strict = !!opt.strict
+    this.maxMetaEntrySize = opt.maxMetaEntrySize || maxMetaEntrySize
+    this.filter = typeof opt.filter === 'function' ? opt.filter : noop
+    // Unlike gzip, brotli doesn't have any magic bytes to identify it
+    // Users need to explicitly tell us they're extracting a brotli file
+    // Or we infer from the file extension
+    const isTBR = (opt.file && (
+        opt.file.endsWith('.tar.br') || opt.file.endsWith('.tbr')))
+    // if it's a tbr file it MIGHT be brotli, but we don't know until
+    // we look at it and verify it's not a valid tar file.
+    this.brotli = !opt.gzip && opt.brotli !== undefined ? opt.brotli
+      : isTBR ? undefined
+      : false
+
+    // have to set this so that streams are ok piping into it
+    this.writable = true
+    this.readable = false
+
+    this[QUEUE] = new Yallist()
+    this[BUFFER] = null
+    this[READENTRY] = null
+    this[WRITEENTRY] = null
+    this[STATE] = 'begin'
+    this[META] = ''
+    this[EX] = null
+    this[GEX] = null
+    this[ENDED] = false
+    this[UNZIP] = null
+    this[ABORTED] = false
+    this[SAW_NULL_BLOCK] = false
+    this[SAW_EOF] = false
+
+    this.on('end', () => this[CLOSESTREAM]())
+
+    if (typeof opt.onwarn === 'function') {
+      this.on('warn', opt.onwarn)
+    }
+    if (typeof opt.onentry === 'function') {
+      this.on('entry', opt.onentry)
+    }
+  }
+
+  [CONSUMEHEADER] (chunk, position) {
+    if (this[SAW_VALID_ENTRY] === null) {
+      this[SAW_VALID_ENTRY] = false
+    }
+    let header
+    try {
+      header = new Header(chunk, position, this[EX], this[GEX])
+    } catch (er) {
+      return this.warn('TAR_ENTRY_INVALID', er)
+    }
+
+    if (header.nullBlock) {
+      if (this[SAW_NULL_BLOCK]) {
+        this[SAW_EOF] = true
+        // ending an archive with no entries.  pointless, but legal.
+        if (this[STATE] === 'begin') {
+          this[STATE] = 'header'
+        }
+        this[EMIT]('eof')
+      } else {
+        this[SAW_NULL_BLOCK] = true
+        this[EMIT]('nullBlock')
+      }
+    } else {
+      this[SAW_NULL_BLOCK] = false
+      if (!header.cksumValid) {
+        this.warn('TAR_ENTRY_INVALID', 'checksum failure', { header })
+      } else if (!header.path) {
+        this.warn('TAR_ENTRY_INVALID', 'path is required', { header })
+      } else {
+        const type = header.type
+        if (/^(Symbolic)?Link$/.test(type) && !header.linkpath) {
+          this.warn('TAR_ENTRY_INVALID', 'linkpath required', { header })
+        } else if (!/^(Symbolic)?Link$/.test(type) && header.linkpath) {
+          this.warn('TAR_ENTRY_INVALID', 'linkpath forbidden', { header })
+        } else {
+          const entry = this[WRITEENTRY] = new Entry(header, this[EX], this[GEX])
+
+          // we do this for meta & ignored entries as well, because they
+          // are still valid tar, or else we wouldn't know to ignore them
+          if (!this[SAW_VALID_ENTRY]) {
+            if (entry.remain) {
+              // this might be the one!
+              const onend = () => {
+                if (!entry.invalid) {
+                  this[SAW_VALID_ENTRY] = true
+                }
+              }
+              entry.on('end', onend)
+            } else {
+              this[SAW_VALID_ENTRY] = true
+            }
+          }
+
+          if (entry.meta) {
+            if (entry.size > this.maxMetaEntrySize) {
+              entry.ignore = true
+              this[EMIT]('ignoredEntry', entry)
+              this[STATE] = 'ignore'
+              entry.resume()
+            } else if (entry.size > 0) {
+              this[META] = ''
+              entry.on('data', c => this[META] += c)
+              this[STATE] = 'meta'
+            }
+          } else {
+            this[EX] = null
+            entry.ignore = entry.ignore || !this.filter(entry.path, entry)
+
+            if (entry.ignore) {
+              // probably valid, just not something we care about
+              this[EMIT]('ignoredEntry', entry)
+              this[STATE] = entry.remain ? 'ignore' : 'header'
+              entry.resume()
+            } else {
+              if (entry.remain) {
+                this[STATE] = 'body'
+              } else {
+                this[STATE] = 'header'
+                entry.end()
+              }
+
+              if (!this[READENTRY]) {
+                this[QUEUE].push(entry)
+                this[NEXTENTRY]()
+              } else {
+                this[QUEUE].push(entry)
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  [CLOSESTREAM] () {
+    nextTick(() => this.emit('close'))
+  }
+
+  [PROCESSENTRY] (entry) {
+    let go = true
+
+    if (!entry) {
+      this[READENTRY] = null
+      go = false
+    } else if (Array.isArray(entry)) {
+      this.emit.apply(this, entry)
+    } else {
+      this[READENTRY] = entry
+      this.emit('entry', entry)
+      if (!entry.emittedEnd) {
+        entry.on('end', _ => this[NEXTENTRY]())
+        go = false
+      }
+    }
+
+    return go
+  }
+
+  [NEXTENTRY] () {
+    do {} while (this[PROCESSENTRY](this[QUEUE].shift()))
+
+    if (!this[QUEUE].length) {
+      // At this point, there's nothing in the queue, but we may have an
+      // entry which is being consumed (readEntry).
+      // If we don't, then we definitely can handle more data.
+      // If we do, and either it's flowing, or it has never had any data
+      // written to it, then it needs more.
+      // The only other possibility is that it has returned false from a
+      // write() call, so we wait for the next drain to continue.
+      const re = this[READENTRY]
+      const drainNow = !re || re.flowing || re.size === re.remain
+      if (drainNow) {
+        if (!this[WRITING]) {
+          this.emit('drain')
+        }
+      } else {
+        re.once('drain', _ => this.emit('drain'))
+      }
+    }
+  }
+
+  [CONSUMEBODY] (chunk, position) {
+    // write up to but no  more than writeEntry.blockRemain
+    const entry = this[WRITEENTRY]
+    const br = entry.blockRemain
+    const c = (br >= chunk.length && position === 0) ? chunk
+      : chunk.slice(position, position + br)
+
+    entry.write(c)
+
+    if (!entry.blockRemain) {
+      this[STATE] = 'header'
+      this[WRITEENTRY] = null
+      entry.end()
+    }
+
+    return c.length
+  }
+
+  [CONSUMEMETA] (chunk, position) {
+    const entry = this[WRITEENTRY]
+    const ret = this[CONSUMEBODY](chunk, position)
+
+    // if we finished, then the entry is reset
+    if (!this[WRITEENTRY]) {
+      this[EMITMETA](entry)
+    }
+
+    return ret
+  }
+
+  [EMIT] (ev, data, extra) {
+    if (!this[QUEUE].length && !this[READENTRY]) {
+      this.emit(ev, data, extra)
+    } else {
+      this[QUEUE].push([ev, data, extra])
+    }
+  }
+
+  [EMITMETA] (entry) {
+    this[EMIT]('meta', this[META])
+    switch (entry.type) {
+      case 'ExtendedHeader':
+      case 'OldExtendedHeader':
+        this[EX] = Pax.parse(this[META], this[EX], false)
+        break
+
+      case 'GlobalExtendedHeader':
+        this[GEX] = Pax.parse(this[META], this[GEX], true)
+        break
+
+      case 'NextFileHasLongPath':
+      case 'OldGnuLongPath':
+        this[EX] = this[EX] || Object.create(null)
+        this[EX].path = this[META].replace(/\0.*/, '')
+        break
+
+      case 'NextFileHasLongLinkpath':
+        this[EX] = this[EX] || Object.create(null)
+        this[EX].linkpath = this[META].replace(/\0.*/, '')
+        break
+
+      /* istanbul ignore next */
+      default: throw new Error('unknown meta: ' + entry.type)
+    }
+  }
+
+  abort (error) {
+    this[ABORTED] = true
+    this.emit('abort', error)
+    // always throws, even in non-strict mode
+    this.warn('TAR_ABORT', error, { recoverable: false })
+  }
+
+  write (chunk) {
+    if (this[ABORTED]) {
+      return
+    }
+
+    // first write, might be gzipped
+    const needSniff = this[UNZIP] === null ||
+      this.brotli === undefined && this[UNZIP] === false
+    if (needSniff && chunk) {
+      if (this[BUFFER]) {
+        chunk = Buffer.concat([this[BUFFER], chunk])
+        this[BUFFER] = null
+      }
+      if (chunk.length < gzipHeader.length) {
+        this[BUFFER] = chunk
+        return true
+      }
+
+      // look for gzip header
+      for (let i = 0; this[UNZIP] === null && i < gzipHeader.length; i++) {
+        if (chunk[i] !== gzipHeader[i]) {
+          this[UNZIP] = false
+        }
+      }
+
+      const maybeBrotli = this.brotli === undefined
+      if (this[UNZIP] === false && maybeBrotli) {
+        // read the first header to see if it's a valid tar file. If so,
+        // we can safely assume that it's not actually brotli, despite the
+        // .tbr or .tar.br file extension.
+        // if we ended before getting a full chunk, yes, def brotli
+        if (chunk.length < 512) {
+          if (this[ENDED]) {
+            this.brotli = true
+          } else {
+            this[BUFFER] = chunk
+            return true
+          }
+        } else {
+          // if it's tar, it's pretty reliably not brotli, chances of
+          // that happening are astronomical.
+          try {
+            new Header(chunk.slice(0, 512))
+            this.brotli = false
+          } catch (_) {
+            this.brotli = true
+          }
+        }
+      }
+
+      if (this[UNZIP] === null || (this[UNZIP] === false && this.brotli)) {
+        const ended = this[ENDED]
+        this[ENDED] = false
+        this[UNZIP] = this[UNZIP] === null
+          ? new zlib.Unzip()
+          : new zlib.BrotliDecompress()
+        this[UNZIP].on('data', chunk => this[CONSUMECHUNK](chunk))
+        this[UNZIP].on('error', er => this.abort(er))
+        this[UNZIP].on('end', _ => {
+          this[ENDED] = true
+          this[CONSUMECHUNK]()
+        })
+        this[WRITING] = true
+        const ret = this[UNZIP][ended ? 'end' : 'write'](chunk)
+        this[WRITING] = false
+        return ret
+      }
+    }
+
+    this[WRITING] = true
+    if (this[UNZIP]) {
+      this[UNZIP].write(chunk)
+    } else {
+      this[CONSUMECHUNK](chunk)
+    }
+    this[WRITING] = false
+
+    // return false if there's a queue, or if the current entry isn't flowing
+    const ret =
+      this[QUEUE].length ? false :
+      this[READENTRY] ? this[READENTRY].flowing :
+      true
+
+    // if we have no queue, then that means a clogged READENTRY
+    if (!ret && !this[QUEUE].length) {
+      this[READENTRY].once('drain', _ => this.emit('drain'))
+    }
+
+    return ret
+  }
+
+  [BUFFERCONCAT] (c) {
+    if (c && !this[ABORTED]) {
+      this[BUFFER] = this[BUFFER] ? Buffer.concat([this[BUFFER], c]) : c
+    }
+  }
+
+  [MAYBEEND] () {
+    if (this[ENDED] &&
+        !this[EMITTEDEND] &&
+        !this[ABORTED] &&
+        !this[CONSUMING]) {
+      this[EMITTEDEND] = true
+      const entry = this[WRITEENTRY]
+      if (entry && entry.blockRemain) {
+        // truncated, likely a damaged file
+        const have = this[BUFFER] ? this[BUFFER].length : 0
+        this.warn('TAR_BAD_ARCHIVE', `Truncated input (needed ${
+          entry.blockRemain} more bytes, only ${have} available)`, { entry })
+        if (this[BUFFER]) {
+          entry.write(this[BUFFER])
+        }
+        entry.end()
+      }
+      this[EMIT](DONE)
+    }
+  }
+
+  [CONSUMECHUNK] (chunk) {
+    if (this[CONSUMING]) {
+      this[BUFFERCONCAT](chunk)
+    } else if (!chunk && !this[BUFFER]) {
+      this[MAYBEEND]()
+    } else {
+      this[CONSUMING] = true
+      if (this[BUFFER]) {
+        this[BUFFERCONCAT](chunk)
+        const c = this[BUFFER]
+        this[BUFFER] = null
+        this[CONSUMECHUNKSUB](c)
+      } else {
+        this[CONSUMECHUNKSUB](chunk)
+      }
+
+      while (this[BUFFER] &&
+          this[BUFFER].length >= 512 &&
+          !this[ABORTED] &&
+          !this[SAW_EOF]) {
+        const c = this[BUFFER]
+        this[BUFFER] = null
+        this[CONSUMECHUNKSUB](c)
+      }
+      this[CONSUMING] = false
+    }
+
+    if (!this[BUFFER] || this[ENDED]) {
+      this[MAYBEEND]()
+    }
+  }
+
+  [CONSUMECHUNKSUB] (chunk) {
+    // we know that we are in CONSUMING mode, so anything written goes into
+    // the buffer.  Advance the position and put any remainder in the buffer.
+    let position = 0
+    const length = chunk.length
+    while (position + 512 <= length && !this[ABORTED] && !this[SAW_EOF]) {
+      switch (this[STATE]) {
+        case 'begin':
+        case 'header':
+          this[CONSUMEHEADER](chunk, position)
+          position += 512
+          break
+
+        case 'ignore':
+        case 'body':
+          position += this[CONSUMEBODY](chunk, position)
+          break
+
+        case 'meta':
+          position += this[CONSUMEMETA](chunk, position)
+          break
+
+        /* istanbul ignore next */
+        default:
+          throw new Error('invalid state: ' + this[STATE])
+      }
+    }
+
+    if (position < length) {
+      if (this[BUFFER]) {
+        this[BUFFER] = Buffer.concat([chunk.slice(position), this[BUFFER]])
+      } else {
+        this[BUFFER] = chunk.slice(position)
+      }
+    }
+  }
+
+  end (chunk) {
+    if (!this[ABORTED]) {
+      if (this[UNZIP]) {
+        this[UNZIP].end(chunk)
+      } else {
+        this[ENDED] = true
+        if (this.brotli === undefined) chunk = chunk || Buffer.alloc(0)
+        this.write(chunk)
+      }
+    }
+  }
+})
diff --git a/server/node_modules/tar/lib/path-reservations.js b/server/node_modules/tar/lib/path-reservations.js
new file mode 100644
index 0000000..8d349d5
--- /dev/null
+++ b/server/node_modules/tar/lib/path-reservations.js
@@ -0,0 +1,156 @@
+// A path exclusive reservation system
+// reserve([list, of, paths], fn)
+// When the fn is first in line for all its paths, it
+// is called with a cb that clears the reservation.
+//
+// Used by async unpack to avoid clobbering paths in use,
+// while still allowing maximal safe parallelization.
+
+const assert = require('assert')
+const normalize = require('./normalize-unicode.js')
+const stripSlashes = require('./strip-trailing-slashes.js')
+const { join } = require('path')
+
+const platform = process.env.TESTING_TAR_FAKE_PLATFORM || process.platform
+const isWindows = platform === 'win32'
+
+module.exports = () => {
+  // path => [function or Set]
+  // A Set object means a directory reservation
+  // A fn is a direct reservation on that path
+  const queues = new Map()
+
+  // fn => {paths:[path,...], dirs:[path, ...]}
+  const reservations = new Map()
+
+  // return a set of parent dirs for a given path
+  // '/a/b/c/d' -> ['/', '/a', '/a/b', '/a/b/c', '/a/b/c/d']
+  const getDirs = path => {
+    const dirs = path.split('/').slice(0, -1).reduce((set, path) => {
+      if (set.length) {
+        path = join(set[set.length - 1], path)
+      }
+      set.push(path || '/')
+      return set
+    }, [])
+    return dirs
+  }
+
+  // functions currently running
+  const running = new Set()
+
+  // return the queues for each path the function cares about
+  // fn => {paths, dirs}
+  const getQueues = fn => {
+    const res = reservations.get(fn)
+    /* istanbul ignore if - unpossible */
+    if (!res) {
+      throw new Error('function does not have any path reservations')
+    }
+    return {
+      paths: res.paths.map(path => queues.get(path)),
+      dirs: [...res.dirs].map(path => queues.get(path)),
+    }
+  }
+
+  // check if fn is first in line for all its paths, and is
+  // included in the first set for all its dir queues
+  const check = fn => {
+    const { paths, dirs } = getQueues(fn)
+    return paths.every(q => q[0] === fn) &&
+      dirs.every(q => q[0] instanceof Set && q[0].has(fn))
+  }
+
+  // run the function if it's first in line and not already running
+  const run = fn => {
+    if (running.has(fn) || !check(fn)) {
+      return false
+    }
+    running.add(fn)
+    fn(() => clear(fn))
+    return true
+  }
+
+  const clear = fn => {
+    if (!running.has(fn)) {
+      return false
+    }
+
+    const { paths, dirs } = reservations.get(fn)
+    const next = new Set()
+
+    paths.forEach(path => {
+      const q = queues.get(path)
+      assert.equal(q[0], fn)
+      if (q.length === 1) {
+        queues.delete(path)
+      } else {
+        q.shift()
+        if (typeof q[0] === 'function') {
+          next.add(q[0])
+        } else {
+          q[0].forEach(fn => next.add(fn))
+        }
+      }
+    })
+
+    dirs.forEach(dir => {
+      const q = queues.get(dir)
+      assert(q[0] instanceof Set)
+      if (q[0].size === 1 && q.length === 1) {
+        queues.delete(dir)
+      } else if (q[0].size === 1) {
+        q.shift()
+
+        // must be a function or else the Set would've been reused
+        next.add(q[0])
+      } else {
+        q[0].delete(fn)
+      }
+    })
+    running.delete(fn)
+
+    next.forEach(fn => run(fn))
+    return true
+  }
+
+  const reserve = (paths, fn) => {
+    // collide on matches across case and unicode normalization
+    // On windows, thanks to the magic of 8.3 shortnames, it is fundamentally
+    // impossible to determine whether two paths refer to the same thing on
+    // disk, without asking the kernel for a shortname.
+    // So, we just pretend that every path matches every other path here,
+    // effectively removing all parallelization on windows.
+    paths = isWindows ? ['win32 parallelization disabled'] : paths.map(p => {
+      // don't need normPath, because we skip this entirely for windows
+      return stripSlashes(join(normalize(p))).toLowerCase()
+    })
+
+    const dirs = new Set(
+      paths.map(path => getDirs(path)).reduce((a, b) => a.concat(b))
+    )
+    reservations.set(fn, { dirs, paths })
+    paths.forEach(path => {
+      const q = queues.get(path)
+      if (!q) {
+        queues.set(path, [fn])
+      } else {
+        q.push(fn)
+      }
+    })
+    dirs.forEach(dir => {
+      const q = queues.get(dir)
+      if (!q) {
+        queues.set(dir, [new Set([fn])])
+      } else if (q[q.length - 1] instanceof Set) {
+        q[q.length - 1].add(fn)
+      } else {
+        q.push(new Set([fn]))
+      }
+    })
+
+    return run(fn)
+  }
+
+  return { check, reserve }
+}
diff --git a/server/node_modules/tar/lib/pax.js b/server/node_modules/tar/lib/pax.js
new file mode 100644
index 0000000..4a7ca85
--- /dev/null
+++ b/server/node_modules/tar/lib/pax.js
@@ -0,0 +1,150 @@
+'use strict'
+const Header = require('./header.js')
+const path = require('path')
+
+class Pax {
+  constructor (obj, global) {
+    this.atime = obj.atime || null
+    this.charset = obj.charset || null
+    this.comment = obj.comment || null
+    this.ctime = obj.ctime || null
+    this.gid = obj.gid || null
+    this.gname = obj.gname || null
+    this.linkpath = obj.linkpath || null
+    this.mtime = obj.mtime || null
+    this.path = obj.path || null
+    this.size = obj.size || null
+    this.uid = obj.uid || null
+    this.uname = obj.uname || null
+    this.dev = obj.dev || null
+    this.ino = obj.ino || null
+    this.nlink = obj.nlink || null
+    this.global = global || false
+  }
+
+  encode () {
+    const body = this.encodeBody()
+    if (body === '') {
+      return null
+    }
+
+    const bodyLen = Buffer.byteLength(body)
+    // round up to 512 bytes
+    // add 512 for header
+    const bufLen = 512 * Math.ceil(1 + bodyLen / 512)
+    const buf = Buffer.allocUnsafe(bufLen)
+
+    // 0-fill the header section, it might not hit every field
+    for (let i = 0; i < 512; i++) {
+      buf[i] = 0
+    }
+
+    new Header({
+      // XXX split the path
+      // then the path should be PaxHeader + basename, but less than 99,
+      // prepend with the dirname
+      path: ('PaxHeader/' + path.basename(this.path)).slice(0, 99),
+      mode: this.mode || 0o644,
+      uid: this.uid || null,
+      gid: this.gid || null,
+      size: bodyLen,
+      mtime: this.mtime || null,
+      type: this.global ? 'GlobalExtendedHeader' : 'ExtendedHeader',
+      linkpath: '',
+      uname: this.uname || '',
+      gname: this.gname || '',
+      devmaj: 0,
+      devmin: 0,
+      atime: this.atime || null,
+      ctime: this.ctime || null,
+    }).encode(buf)
+
+    buf.write(body, 512, bodyLen, 'utf8')
+
+    // null pad after the body
+    for (let i = bodyLen + 512; i < buf.length; i++) {
+      buf[i] = 0
+    }
+
+    return buf
+  }
+
+  encodeBody () {
+    return (
+      this.encodeField('path') +
+      this.encodeField('ctime') +
+      this.encodeField('atime') +
+      this.encodeField('dev') +
+      this.encodeField('ino') +
+      this.encodeField('nlink') +
+      this.encodeField('charset') +
+      this.encodeField('comment') +
+      this.encodeField('gid') +
+      this.encodeField('gname') +
+      this.encodeField('linkpath') +
+      this.encodeField('mtime') +
+      this.encodeField('size') +
+      this.encodeField('uid') +
+      this.encodeField('uname')
+    )
+  }
+
+  encodeField (field) {
+    if (this[field] === null || this[field] === undefined) {
+      return ''
+    }
+    const v = this[field] instanceof Date ? this[field].getTime() / 1000
+      : this[field]
+    const s = ' ' +
+      (field === 'dev' || field === 'ino' || field === 'nlink'
+        ? 'SCHILY.' : '') +
+      field + '=' + v + '\n'
+    const byteLen = Buffer.byteLength(s)
+    // the digits includes the length of the digits in ascii base-10
+    // so if it's 9 characters, then adding 1 for the 9 makes it 10
+    // which makes it 11 chars.
+    let digits = Math.floor(Math.log(byteLen) / Math.log(10)) + 1
+    if (byteLen + digits >= Math.pow(10, digits)) {
+      digits += 1
+    }
+    const len = digits + byteLen
+    return len + s
+  }
+}
+
+Pax.parse = (string, ex, g) => new Pax(merge(parseKV(string), ex), g)
+
+const merge = (a, b) =>
+  b ? Object.keys(a).reduce((s, k) => (s[k] = a[k], s), b) : a
+
+const parseKV = string =>
+  string
+    .replace(/\n$/, '')
+    .split('\n')
+    .reduce(parseKVLine, Object.create(null))
+
+const parseKVLine = (set, line) => {
+  const n = parseInt(line, 10)
+
+  // XXX Values with \n in them will fail this.
+  // Refactor to not be a naive line-by-line parse.
+  if (n !== Buffer.byteLength(line) + 1) {
+    return set
+  }
+
+  line = line.slice((n + ' ').length)
+  const kv = line.split('=')
+  const k = kv.shift().replace(/^SCHILY\.(dev|ino|nlink)/, '$1')
+  if (!k) {
+    return set
+  }
+
+  const v = kv.join('=')
+  set[k] = /^([A-Z]+\.)?([mac]|birth|creation)time$/.test(k)
+    ? new Date(v * 1000)
+    : /^[0-9]+$/.test(v) ? +v
+    : v
+  return set
+}
+
+module.exports = Pax
diff --git a/server/node_modules/tar/lib/read-entry.js b/server/node_modules/tar/lib/read-entry.js
new file mode 100644
index 0000000..6186266
--- /dev/null
+++ b/server/node_modules/tar/lib/read-entry.js
@@ -0,0 +1,107 @@
+'use strict'
+const { Minipass } = require('minipass')
+const normPath = require('./normalize-windows-path.js')
+
+const SLURP = Symbol('slurp')
+module.exports = class ReadEntry extends Minipass {
+  constructor (header, ex, gex) {
+    super()
+    // read entries always start life paused.  this is to avoid the
+    // situation where Minipass's auto-ending empty streams results
+    // in an entry ending before we're ready for it.
+    this.pause()
+    this.extended = ex
+    this.globalExtended = gex
+    this.header = header
+    this.startBlockSize = 512 * Math.ceil(header.size / 512)
+    this.blockRemain = this.startBlockSize
+    this.remain = header.size
+    this.type = header.type
+    this.meta = false
+    this.ignore = false
+    switch (this.type) {
+      case 'File':
+      case 'OldFile':
+      case 'Link':
+      case 'SymbolicLink':
+      case 'CharacterDevice':
+      case 'BlockDevice':
+      case 'Directory':
+      case 'FIFO':
+      case 'ContiguousFile':
+      case 'GNUDumpDir':
+        break
+
+      case 'NextFileHasLongLinkpath':
+      case 'NextFileHasLongPath':
+      case 'OldGnuLongPath':
+      case 'GlobalExtendedHeader':
+      case 'ExtendedHeader':
+      case 'OldExtendedHeader':
+        this.meta = true
+        break
+
+      // NOTE: gnutar and bsdtar treat unrecognized types as 'File'
+      // it may be worth doing the same, but with a warning.
+      default:
+        this.ignore = true
+    }
+
+    this.path = normPath(header.path)
+    this.mode = header.mode
+    if (this.mode) {
+      this.mode = this.mode & 0o7777
+    }
+    this.uid = header.uid
+    this.gid = header.gid
+    this.uname = header.uname
+    this.gname = header.gname
+    this.size = header.size
+    this.mtime = header.mtime
+    this.atime = header.atime
+    this.ctime = header.ctime
+    this.linkpath = normPath(header.linkpath)
+    this.uname = header.uname
+    this.gname = header.gname
+
+    if (ex) {
+      this[SLURP](ex)
+    }
+    if (gex) {
+      this[SLURP](gex, true)
+    }
+  }
+
+  write (data) {
+    const writeLen = data.length
+    if (writeLen > this.blockRemain) {
+      throw new Error('writing more to entry than is appropriate')
+    }
+
+    const r = this.remain
+    const br = this.blockRemain
+    this.remain = Math.max(0, r - writeLen)
+    this.blockRemain = Math.max(0, br - writeLen)
+    if (this.ignore) {
+      return true
+    }
+
+    if (r >= writeLen) {
+      return super.write(data)
+    }
+
+    // r < writeLen
+    return super.write(data.slice(0, r))
+  }
+
+  [SLURP] (ex, global) {
+    for (const k in ex) {
+      // we slurp in everything except for the path attribute in
+      // a global extended header, because that's weird.
+      if (ex[k] !== null && ex[k] !== undefined &&
+          !(global && k === 'path')) {
+        this[k] = k === 'path' || k === 'linkpath' ? normPath(ex[k]) : ex[k]
+      }
+    }
+  }
+}
diff --git a/server/node_modules/tar/lib/replace.js b/server/node_modules/tar/lib/replace.js
new file mode 100644
index 0000000..8db6800
--- /dev/null
+++ b/server/node_modules/tar/lib/replace.js
@@ -0,0 +1,246 @@
+'use strict'
+
+// tar -r
+const hlo = require('./high-level-opt.js')
+const Pack = require('./pack.js')
+const fs = require('fs')
+const fsm = require('fs-minipass')
+const t = require('./list.js')
+const path = require('path')
+
+// starting at the head of the file, read a Header
+// If the checksum is invalid, that's our position to start writing
+// If it is, jump forward by the specified size (round up to 512)
+// and try again.
+// Write the new Pack stream starting there.
+
+const Header = require('./header.js')
+
+module.exports = (opt_, files, cb) => {
+  const opt = hlo(opt_)
+
+  if (!opt.file) {
+    throw new TypeError('file is required')
+  }
+
+  if (opt.gzip || opt.brotli || opt.file.endsWith('.br') || opt.file.endsWith('.tbr')) {
+    throw new TypeError('cannot append to compressed archives')
+  }
+
+  if (!files || !Array.isArray(files) || !files.length) {
+    throw new TypeError('no files or directories specified')
+  }
+
+  files = Array.from(files)
+
+  return opt.sync ? replaceSync(opt, files)
+    : replace(opt, files, cb)
+}
+
+const replaceSync = (opt, files) => {
+  const p = new Pack.Sync(opt)
+
+  let threw = true
+  let fd
+  let position
+
+  try {
+    try {
+      fd = fs.openSync(opt.file, 'r+')
+    } catch (er) {
+      if (er.code === 'ENOENT') {
+        fd = fs.openSync(opt.file, 'w+')
+      } else {
+        throw er
+      }
+    }
+
+    const st = fs.fstatSync(fd)
+    const headBuf = Buffer.alloc(512)
+
+    POSITION: for (position = 0; position < st.size; position += 512) {
+      for (let bufPos = 0, bytes = 0; bufPos < 512; bufPos += bytes) {
+        bytes = fs.readSync(
+          fd, headBuf, bufPos, headBuf.length - bufPos, position + bufPos
+        )
+
+        if (position === 0 && headBuf[0] === 0x1f && headBuf[1] === 0x8b) {
+          throw new Error('cannot append to compressed archives')
+        }
+
+        if (!bytes) {
+          break POSITION
+        }
+      }
+
+      const h = new Header(headBuf)
+      if (!h.cksumValid) {
+        break
+      }
+      const entryBlockSize = 512 * Math.ceil(h.size / 512)
+      if (position + entryBlockSize + 512 > st.size) {
+        break
+      }
+      // the 512 for the header we just parsed will be added as well
+      // also jump ahead all the blocks for the body
+      position += entryBlockSize
+      if (opt.mtimeCache) {
+        opt.mtimeCache.set(h.path, h.mtime)
+      }
+    }
+    threw = false
+
+    streamSync(opt, p, position, fd, files)
+  } finally {
+    if (threw) {
+      try {
+        fs.closeSync(fd)
+      } catch (er) {}
+    }
+  }
+}
+
+const streamSync = (opt, p, position, fd, files) => {
+  const stream = new fsm.WriteStreamSync(opt.file, {
+    fd: fd,
+    start: position,
+  })
+  p.pipe(stream)
+  addFilesSync(p, files)
+}
+
+const replace = (opt, files, cb) => {
+  files = Array.from(files)
+  const p = new Pack(opt)
+
+  const getPos = (fd, size, cb_) => {
+    const cb = (er, pos) => {
+      if (er) {
+        fs.close(fd, _ => cb_(er))
+      } else {
+        cb_(null, pos)
+      }
+    }
+
+    let position = 0
+    if (size === 0) {
+      return cb(null, 0)
+    }
+
+    let bufPos = 0
+    const headBuf = Buffer.alloc(512)
+    const onread = (er, bytes) => {
+      if (er) {
+        return cb(er)
+      }
+      bufPos += bytes
+      if (bufPos < 512 && bytes) {
+        return fs.read(
+          fd, headBuf, bufPos, headBuf.length - bufPos,
+          position + bufPos, onread
+        )
+      }
+
+      if (position === 0 && headBuf[0] === 0x1f && headBuf[1] === 0x8b) {
+        return cb(new Error('cannot append to compressed archives'))
+      }
+
+      // truncated header
+      if (bufPos < 512) {
+        return cb(null, position)
+      }
+
+      const h = new Header(headBuf)
+      if (!h.cksumValid) {
+        return cb(null, position)
+      }
+
+      const entryBlockSize = 512 * Math.ceil(h.size / 512)
+      if (position + entryBlockSize + 512 > size) {
+        return cb(null, position)
+      }
+
+      position += entryBlockSize + 512
+      if (position >= size) {
+        return cb(null, position)
+      }
+
+      if (opt.mtimeCache) {
+        opt.mtimeCache.set(h.path, h.mtime)
+      }
+      bufPos = 0
+      fs.read(fd, headBuf, 0, 512, position, onread)
+    }
+    fs.read(fd, headBuf, 0, 512, position, onread)
+  }
+
+  const promise = new Promise((resolve, reject) => {
+    p.on('error', reject)
+    let flag = 'r+'
+    const onopen = (er, fd) => {
+      if (er && er.code === 'ENOENT' && flag === 'r+') {
+        flag = 'w+'
+        return fs.open(opt.file, flag, onopen)
+      }
+
+      if (er) {
+        return reject(er)
+      }
+
+      fs.fstat(fd, (er, st) => {
+        if (er) {
+          return fs.close(fd, () => reject(er))
+        }
+
+        getPos(fd, st.size, (er, position) => {
+          if (er) {
+            return reject(er)
+          }
+          const stream = new fsm.WriteStream(opt.file, {
+            fd: fd,
+            start: position,
+          })
+          p.pipe(stream)
+          stream.on('error', reject)
+          stream.on('close', resolve)
+          addFilesAsync(p, files)
+        })
+      })
+    }
+    fs.open(opt.file, flag, onopen)
+  })
+
+  return cb ? promise.then(cb, cb) : promise
+}
+
+const addFilesSync = (p, files) => {
+  files.forEach(file => {
+    if (file.charAt(0) === '@') {
+      t({
+        file: path.resolve(p.cwd, file.slice(1)),
+        sync: true,
+        noResume: true,
+        onentry: entry => p.add(entry),
+      })
+    } else {
+      p.add(file)
+    }
+  })
+  p.end()
+}
+
+const addFilesAsync = (p, files) => {
+  while (files.length) {
+    const file = files.shift()
+    if (file.charAt(0) === '@') {
+      return t({
+        file: path.resolve(p.cwd, file.slice(1)),
+        noResume: true,
+        onentry: entry => p.add(entry),
+      }).then(_ => addFilesAsync(p, files))
+    } else {
+      p.add(file)
+    }
+  }
+  p.end()
+}
diff --git a/server/node_modules/tar/lib/strip-absolute-path.js b/server/node_modules/tar/lib/strip-absolute-path.js
new file mode 100644
index 0000000..185e2de
--- /dev/null
+++ b/server/node_modules/tar/lib/strip-absolute-path.js
@@ -0,0 +1,24 @@
+// unix absolute paths are also absolute on win32, so we use this for both
+const { isAbsolute, parse } = require('path').win32
+
+// returns [root, stripped]
+// Note that windows will think that //x/y/z/a has a "root" of //x/y, and in
+// those cases, we want to sanitize it to x/y/z/a, not z/a, so we strip /
+// explicitly if it's the first character.
+// drive-specific relative paths on Windows get their root stripped off even
+// though they are not absolute, so `c:../foo` becomes ['c:', '../foo']
+module.exports = path => {
+  let r = ''
+
+  let parsed = parse(path)
+  while (isAbsolute(path) || parsed.root) {
+    // windows will think that //x/y/z has a "root" of //x/y/
+    // but strip the //?/C:/ off of //?/C:/path
+    const root = path.charAt(0) === '/' && path.slice(0, 4) !== '//?/' ? '/'
+      : parsed.root
+    path = path.slice(root.length)
+    r += root
+    parsed = parse(path)
+  }
+  return [r, path]
+}
diff --git a/server/node_modules/tar/lib/strip-trailing-slashes.js b/server/node_modules/tar/lib/strip-trailing-slashes.js
new file mode 100644
index 0000000..3e3ecec
--- /dev/null
+++ b/server/node_modules/tar/lib/strip-trailing-slashes.js
@@ -0,0 +1,13 @@
+// warning: extremely hot code path.
+// This has been meticulously optimized for use
+// within npm install on large package trees.
+// Do not edit without careful benchmarking.
+module.exports = str => {
+  let i = str.length - 1
+  let slashesStart = -1
+  while (i > -1 && str.charAt(i) === '/') {
+    slashesStart = i
+    i--
+  }
+  return slashesStart === -1 ? str : str.slice(0, slashesStart)
+}
diff --git a/server/node_modules/tar/lib/types.js b/server/node_modules/tar/lib/types.js
new file mode 100644
index 0000000..7bfc254
--- /dev/null
+++ b/server/node_modules/tar/lib/types.js
@@ -0,0 +1,44 @@
+'use strict'
+// map types from key to human-friendly name
+exports.name = new Map([
+  ['0', 'File'],
+  // same as File
+  ['', 'OldFile'],
+  ['1', 'Link'],
+  ['2', 'SymbolicLink'],
+  // Devices and FIFOs aren't fully supported
+  // they are parsed, but skipped when unpacking
+  ['3', 'CharacterDevice'],
+  ['4', 'BlockDevice'],
+  ['5', 'Directory'],
+  ['6', 'FIFO'],
+  // same as File
+  ['7', 'ContiguousFile'],
+  // pax headers
+  ['g', 'GlobalExtendedHeader'],
+  ['x', 'ExtendedHeader'],
+  // vendor-specific stuff
+  // skip
+  ['A', 'SolarisACL'],
+  // like 5, but with data, which should be skipped
+  ['D', 'GNUDumpDir'],
+  // metadata only, skip
+  ['I', 'Inode'],
+  // data = link path of next file
+  ['K', 'NextFileHasLongLinkpath'],
+  // data = path of next file
+  ['L', 'NextFileHasLongPath'],
+  // skip
+  ['M', 'ContinuationFile'],
+  // like L
+  ['N', 'OldGnuLongPath'],
+  // skip
+  ['S', 'SparseFile'],
+  // skip
+  ['V', 'TapeVolumeHeader'],
+  // like x
+  ['X', 'OldExtendedHeader'],
+])
+
+// map the other direction
+exports.code = new Map(Array.from(exports.name).map(kv => [kv[1], kv[0]]))
diff --git a/server/node_modules/tar/lib/unpack.js b/server/node_modules/tar/lib/unpack.js
new file mode 100644
index 0000000..03172e2
--- /dev/null
+++ b/server/node_modules/tar/lib/unpack.js
@@ -0,0 +1,923 @@
+'use strict'
+
+// the PEND/UNPEND stuff tracks whether we're ready to emit end/close yet.
+// but the path reservations are required to avoid race conditions where
+// parallelized unpack ops may mess with one another, due to dependencies
+// (like a Link depending on its target) or destructive operations (like
+// clobbering an fs object to create one of a different type.)
+
+const assert = require('assert')
+const Parser = require('./parse.js')
+const fs = require('fs')
+const fsm = require('fs-minipass')
+const path = require('path')
+const mkdir = require('./mkdir.js')
+const wc = require('./winchars.js')
+const pathReservations = require('./path-reservations.js')
+const stripAbsolutePath = require('./strip-absolute-path.js')
+const normPath = require('./normalize-windows-path.js')
+const stripSlash = require('./strip-trailing-slashes.js')
+const normalize = require('./normalize-unicode.js')
+
+const ONENTRY = Symbol('onEntry')
+const CHECKFS = Symbol('checkFs')
+const CHECKFS2 = Symbol('checkFs2')
+const PRUNECACHE = Symbol('pruneCache')
+const ISREUSABLE = Symbol('isReusable')
+const MAKEFS = Symbol('makeFs')
+const FILE = Symbol('file')
+const DIRECTORY = Symbol('directory')
+const LINK = Symbol('link')
+const SYMLINK = Symbol('symlink')
+const HARDLINK = Symbol('hardlink')
+const UNSUPPORTED = Symbol('unsupported')
+const CHECKPATH = Symbol('checkPath')
+const MKDIR = Symbol('mkdir')
+const ONERROR = Symbol('onError')
+const PENDING = Symbol('pending')
+const PEND = Symbol('pend')
+const UNPEND = Symbol('unpend')
+const ENDED = Symbol('ended')
+const MAYBECLOSE = Symbol('maybeClose')
+const SKIP = Symbol('skip')
+const DOCHOWN = Symbol('doChown')
+const UID = Symbol('uid')
+const GID = Symbol('gid')
+const CHECKED_CWD = Symbol('checkedCwd')
+const crypto = require('crypto')
+const getFlag = require('./get-write-flag.js')
+const platform = process.env.TESTING_TAR_FAKE_PLATFORM || process.platform
+const isWindows = platform === 'win32'
+const DEFAULT_MAX_DEPTH = 1024
+
+// Unlinks on Windows are not atomic.
+//
+// This means that if you have a file entry, followed by another
+// file entry with an identical name, and you cannot re-use the file
+// (because it's a hardlink, or because unlink:true is set, or it's
+// Windows, which does not have useful nlink values), then the unlink
+// will be committed to the disk AFTER the new file has been written
+// over the old one, deleting the new file.
+//
+// To work around this, on Windows systems, we rename the file and then
+// delete the renamed file.  It's a sloppy kludge, but frankly, I do not
+// know of a better way to do this, given windows' non-atomic unlink
+// semantics.
+//
+// See: https://github.com/npm/node-tar/issues/183
+/* istanbul ignore next */
+const unlinkFile = (path, cb) => {
+  if (!isWindows) {
+    return fs.unlink(path, cb)
+  }
+
+  const name = path + '.DELETE.' + crypto.randomBytes(16).toString('hex')
+  fs.rename(path, name, er => {
+    if (er) {
+      return cb(er)
+    }
+    fs.unlink(name, cb)
+  })
+}
+
+/* istanbul ignore next */
+const unlinkFileSync = path => {
+  if (!isWindows) {
+    return fs.unlinkSync(path)
+  }
+
+  const name = path + '.DELETE.' + crypto.randomBytes(16).toString('hex')
+  fs.renameSync(path, name)
+  fs.unlinkSync(name)
+}
+
+// this.gid, entry.gid, this.processUid
+const uint32 = (a, b, c) =>
+  a === a >>> 0 ? a
+  : b === b >>> 0 ? b
+  : c
+
+// clear the cache if it's a case-insensitive unicode-squashing match.
+// we can't know if the current file system is case-sensitive or supports
+// unicode fully, so we check for similarity on the maximally compatible
+// representation.  Err on the side of pruning, since all it's doing is
+// preventing lstats, and it's not the end of the world if we get a false
+// positive.
+// Note that on windows, we always drop the entire cache whenever a
+// symbolic link is encountered, because 8.3 filenames are impossible
+// to reason about, and collisions are hazards rather than just failures.
+const cacheKeyNormalize = path => stripSlash(normPath(normalize(path)))
+  .toLowerCase()
+
+const pruneCache = (cache, abs) => {
+  abs = cacheKeyNormalize(abs)
+  for (const path of cache.keys()) {
+    const pnorm = cacheKeyNormalize(path)
+    if (pnorm === abs || pnorm.indexOf(abs + '/') === 0) {
+      cache.delete(path)
+    }
+  }
+}
+
+const dropCache = cache => {
+  for (const key of cache.keys()) {
+    cache.delete(key)
+  }
+}
+
+class Unpack extends Parser {
+  constructor (opt) {
+    if (!opt) {
+      opt = {}
+    }
+
+    opt.ondone = _ => {
+      this[ENDED] = true
+      this[MAYBECLOSE]()
+    }
+
+    super(opt)
+
+    this[CHECKED_CWD] = false
+
+    this.reservations = pathReservations()
+
+    this.transform = typeof opt.transform === 'function' ? opt.transform : null
+
+    this.writable = true
+    this.readable = false
+
+    this[PENDING] = 0
+    this[ENDED] = false
+
+    this.dirCache = opt.dirCache || new Map()
+
+    if (typeof opt.uid === 'number' || typeof opt.gid === 'number') {
+      // need both or neither
+      if (typeof opt.uid !== 'number' || typeof opt.gid !== 'number') {
+        throw new TypeError('cannot set owner without number uid and gid')
+      }
+      if (opt.preserveOwner) {
+        throw new TypeError(
+          'cannot preserve owner in archive and also set owner explicitly')
+      }
+      this.uid = opt.uid
+      this.gid = opt.gid
+      this.setOwner = true
+    } else {
+      this.uid = null
+      this.gid = null
+      this.setOwner = false
+    }
+
+    // default true for root
+    if (opt.preserveOwner === undefined && typeof opt.uid !== 'number') {
+      this.preserveOwner = process.getuid && process.getuid() === 0
+    } else {
+      this.preserveOwner = !!opt.preserveOwner
+    }
+
+    this.processUid = (this.preserveOwner || this.setOwner) && process.getuid ?
+      process.getuid() : null
+    this.processGid = (this.preserveOwner || this.setOwner) && process.getgid ?
+      process.getgid() : null
+
+    // prevent excessively deep nesting of subfolders
+    // set to `Infinity` to remove this restriction
+    this.maxDepth = typeof opt.maxDepth === 'number'
+      ? opt.maxDepth
+      : DEFAULT_MAX_DEPTH
+
+    // mostly just for testing, but useful in some cases.
+    // Forcibly trigger a chown on every entry, no matter what
+    this.forceChown = opt.forceChown === true
+
+    // turn ><?| in filenames into 0xf000-higher encoded forms
+    this.win32 = !!opt.win32 || isWindows
+
+    // do not unpack over files that are newer than what's in the archive
+    this.newer = !!opt.newer
+
+    // do not unpack over ANY files
+    this.keep = !!opt.keep
+
+    // do not set mtime/atime of extracted entries
+    this.noMtime = !!opt.noMtime
+
+    // allow .., absolute path entries, and unpacking through symlinks
+    // without this, warn and skip .., relativize absolutes, and error
+    // on symlinks in extraction path
+    this.preservePaths = !!opt.preservePaths
+
+    // unlink files and links before writing. This breaks existing hard
+    // links, and removes symlink directories rather than erroring
+    this.unlink = !!opt.unlink
+
+    this.cwd = normPath(path.resolve(opt.cwd || process.cwd()))
+    this.strip = +opt.strip || 0
+    // if we're not chmodding, then we don't need the process umask
+    this.processUmask = opt.noChmod ? 0 : process.umask()
+    this.umask = typeof opt.umask === 'number' ? opt.umask : this.processUmask
+
+    // default mode for dirs created as parents
+    this.dmode = opt.dmode || (0o0777 & (~this.umask))
+    this.fmode = opt.fmode || (0o0666 & (~this.umask))
+
+    this.on('entry', entry => this[ONENTRY](entry))
+  }
+
+  // a bad or damaged archive is a warning for Parser, but an error
+  // when extracting.  Mark those errors as unrecoverable, because
+  // the Unpack contract cannot be met.
+  warn (code, msg, data = {}) {
+    if (code === 'TAR_BAD_ARCHIVE' || code === 'TAR_ABORT') {
+      data.recoverable = false
+    }
+    return super.warn(code, msg, data)
+  }
+
+  [MAYBECLOSE] () {
+    if (this[ENDED] && this[PENDING] === 0) {
+      this.emit('prefinish')
+      this.emit('finish')
+      this.emit('end')
+    }
+  }
+
+  [CHECKPATH] (entry) {
+    const p = normPath(entry.path)
+    const parts = p.split('/')
+
+    if (this.strip) {
+      if (parts.length < this.strip) {
+        return false
+      }
+      if (entry.type === 'Link') {
+        const linkparts = normPath(entry.linkpath).split('/')
+        if (linkparts.length >= this.strip) {
+          entry.linkpath = linkparts.slice(this.strip).join('/')
+        } else {
+          return false
+        }
+      }
+      parts.splice(0, this.strip)
+      entry.path = parts.join('/')
+    }
+
+    if (isFinite(this.maxDepth) && parts.length > this.maxDepth) {
+      this.warn('TAR_ENTRY_ERROR', 'path excessively deep', {
+        entry,
+        path: p,
+        depth: parts.length,
+        maxDepth: this.maxDepth,
+      })
+      return false
+    }
+
+    if (!this.preservePaths) {
+      if (parts.includes('..') || isWindows && /^[a-z]:\.\.$/i.test(parts[0])) {
+        this.warn('TAR_ENTRY_ERROR', `path contains '..'`, {
+          entry,
+          path: p,
+        })
+        return false
+      }
+
+      // strip off the root
+      const [root, stripped] = stripAbsolutePath(p)
+      if (root) {
+        entry.path = stripped
+        this.warn('TAR_ENTRY_INFO', `stripping ${root} from absolute path`, {
+          entry,
+          path: p,
+        })
+      }
+    }
+
+    if (path.isAbsolute(entry.path)) {
+      entry.absolute = normPath(path.resolve(entry.path))
+    } else {
+      entry.absolute = normPath(path.resolve(this.cwd, entry.path))
+    }
+
+    // if we somehow ended up with a path that escapes the cwd, and we are
+    // not in preservePaths mode, then something is fishy!  This should have
+    // been prevented above, so ignore this for coverage.
+    /* istanbul ignore if - defense in depth */
+    if (!this.preservePaths &&
+        entry.absolute.indexOf(this.cwd + '/') !== 0 &&
+        entry.absolute !== this.cwd) {
+      this.warn('TAR_ENTRY_ERROR', 'path escaped extraction target', {
+        entry,
+        path: normPath(entry.path),
+        resolvedPath: entry.absolute,
+        cwd: this.cwd,
+      })
+      return false
+    }
+
+    // an archive can set properties on the extraction directory, but it
+    // may not replace the cwd with a different kind of thing entirely.
+    if (entry.absolute === this.cwd &&
+        entry.type !== 'Directory' &&
+        entry.type !== 'GNUDumpDir') {
+      return false
+    }
+
+    // only encode : chars that aren't drive letter indicators
+    if (this.win32) {
+      const { root: aRoot } = path.win32.parse(entry.absolute)
+      entry.absolute = aRoot + wc.encode(entry.absolute.slice(aRoot.length))
+      const { root: pRoot } = path.win32.parse(entry.path)
+      entry.path = pRoot + wc.encode(entry.path.slice(pRoot.length))
+    }
+
+    return true
+  }
+
+  [ONENTRY] (entry) {
+    if (!this[CHECKPATH](entry)) {
+      return entry.resume()
+    }
+
+    assert.equal(typeof entry.absolute, 'string')
+
+    switch (entry.type) {
+      case 'Directory':
+      case 'GNUDumpDir':
+        if (entry.mode) {
+          entry.mode = entry.mode | 0o700
+        }
+
+      // eslint-disable-next-line no-fallthrough
+      case 'File':
+      case 'OldFile':
+      case 'ContiguousFile':
+      case 'Link':
+      case 'SymbolicLink':
+        return this[CHECKFS](entry)
+
+      case 'CharacterDevice':
+      case 'BlockDevice':
+      case 'FIFO':
+      default:
+        return this[UNSUPPORTED](entry)
+    }
+  }
+
+  [ONERROR] (er, entry) {
+    // Cwd has to exist, or else nothing works. That's serious.
+    // Other errors are warnings, which raise the error in strict
+    // mode, but otherwise continue on.
+    if (er.name === 'CwdError') {
+      this.emit('error', er)
+    } else {
+      this.warn('TAR_ENTRY_ERROR', er, { entry })
+      this[UNPEND]()
+      entry.resume()
+    }
+  }
+
+  [MKDIR] (dir, mode, cb) {
+    mkdir(normPath(dir), {
+      uid: this.uid,
+      gid: this.gid,
+      processUid: this.processUid,
+      processGid: this.processGid,
+      umask: this.processUmask,
+      preserve: this.preservePaths,
+      unlink: this.unlink,
+      cache: this.dirCache,
+      cwd: this.cwd,
+      mode: mode,
+      noChmod: this.noChmod,
+    }, cb)
+  }
+
+  [DOCHOWN] (entry) {
+    // in preserve owner mode, chown if the entry doesn't match process
+    // in set owner mode, chown if setting doesn't match process
+    return this.forceChown ||
+      this.preserveOwner &&
+      (typeof entry.uid === 'number' && entry.uid !== this.processUid ||
+        typeof entry.gid === 'number' && entry.gid !== this.processGid)
+      ||
+      (typeof this.uid === 'number' && this.uid !== this.processUid ||
+        typeof this.gid === 'number' && this.gid !== this.processGid)
+  }
+
+  [UID] (entry) {
+    return uint32(this.uid, entry.uid, this.processUid)
+  }
+
+  [GID] (entry) {
+    return uint32(this.gid, entry.gid, this.processGid)
+  }
+
+  [FILE] (entry, fullyDone) {
+    const mode = entry.mode & 0o7777 || this.fmode
+    const stream = new fsm.WriteStream(entry.absolute, {
+      flags: getFlag(entry.size),
+      mode: mode,
+      autoClose: false,
+    })
+    stream.on('error', er => {
+      if (stream.fd) {
+        fs.close(stream.fd, () => {})
+      }
+
+      // flush all the data out so that we aren't left hanging
+      // if the error wasn't actually fatal.  otherwise the parse
+      // is blocked, and we never proceed.
+      stream.write = () => true
+      this[ONERROR](er, entry)
+      fullyDone()
+    })
+
+    let actions = 1
+    const done = er => {
+      if (er) {
+        /* istanbul ignore else - we should always have a fd by now */
+        if (stream.fd) {
+          fs.close(stream.fd, () => {})
+        }
+
+        this[ONERROR](er, entry)
+        fullyDone()
+        return
+      }
+
+      if (--actions === 0) {
+        fs.close(stream.fd, er => {
+          if (er) {
+            this[ONERROR](er, entry)
+          } else {
+            this[UNPEND]()
+          }
+          fullyDone()
+        })
+      }
+    }
+
+    stream.on('finish', _ => {
+      // if futimes fails, try utimes
+      // if utimes fails, fail with the original error
+      // same for fchown/chown
+      const abs = entry.absolute
+      const fd = stream.fd
+
+      if (entry.mtime && !this.noMtime) {
+        actions++
+        const atime = entry.atime || new Date()
+        const mtime = entry.mtime
+        fs.futimes(fd, atime, mtime, er =>
+          er ? fs.utimes(abs, atime, mtime, er2 => done(er2 && er))
+          : done())
+      }
+
+      if (this[DOCHOWN](entry)) {
+        actions++
+        const uid = this[UID](entry)
+        const gid = this[GID](entry)
+        fs.fchown(fd, uid, gid, er =>
+          er ? fs.chown(abs, uid, gid, er2 => done(er2 && er))
+          : done())
+      }
+
+      done()
+    })
+
+    const tx = this.transform ? this.transform(entry) || entry : entry
+    if (tx !== entry) {
+      tx.on('error', er => {
+        this[ONERROR](er, entry)
+        fullyDone()
+      })
+      entry.pipe(tx)
+    }
+    tx.pipe(stream)
+  }
+
+  [DIRECTORY] (entry, fullyDone) {
+    const mode = entry.mode & 0o7777 || this.dmode
+    this[MKDIR](entry.absolute, mode, er => {
+      if (er) {
+        this[ONERROR](er, entry)
+        fullyDone()
+        return
+      }
+
+      let actions = 1
+      const done = _ => {
+        if (--actions === 0) {
+          fullyDone()
+          this[UNPEND]()
+          entry.resume()
+        }
+      }
+
+      if (entry.mtime && !this.noMtime) {
+        actions++
+        fs.utimes(entry.absolute, entry.atime || new Date(), entry.mtime, done)
+      }
+
+      if (this[DOCHOWN](entry)) {
+        actions++
+        fs.chown(entry.absolute, this[UID](entry), this[GID](entry), done)
+      }
+
+      done()
+    })
+  }
+
+  [UNSUPPORTED] (entry) {
+    entry.unsupported = true
+    this.warn('TAR_ENTRY_UNSUPPORTED',
+      `unsupported entry type: ${entry.type}`, { entry })
+    entry.resume()
+  }
+
+  [SYMLINK] (entry, done) {
+    this[LINK](entry, entry.linkpath, 'symlink', done)
+  }
+
+  [HARDLINK] (entry, done) {
+    const linkpath = normPath(path.resolve(this.cwd, entry.linkpath))
+    this[LINK](entry, linkpath, 'link', done)
+  }
+
+  [PEND] () {
+    this[PENDING]++
+  }
+
+  [UNPEND] () {
+    this[PENDING]--
+    this[MAYBECLOSE]()
+  }
+
+  [SKIP] (entry) {
+    this[UNPEND]()
+    entry.resume()
+  }
+
+  // Check if we can reuse an existing filesystem entry safely and
+  // overwrite it, rather than unlinking and recreating
+  // Windows doesn't report a useful nlink, so we just never reuse entries
+  [ISREUSABLE] (entry, st) {
+    return entry.type === 'File' &&
+      !this.unlink &&
+      st.isFile() &&
+      st.nlink <= 1 &&
+      !isWindows
+  }
+
+  // check if a thing is there, and if so, try to clobber it
+  [CHECKFS] (entry) {
+    this[PEND]()
+    const paths = [entry.path]
+    if (entry.linkpath) {
+      paths.push(entry.linkpath)
+    }
+    this.reservations.reserve(paths, done => this[CHECKFS2](entry, done))
+  }
+
+  [PRUNECACHE] (entry) {
+    // if we are not creating a directory, and the path is in the dirCache,
+    // then that means we are about to delete the directory we created
+    // previously, and it is no longer going to be a directory, and neither
+    // is any of its children.
+    // If a symbolic link is encountered, all bets are off.  There is no
+    // reasonable way to sanitize the cache in such a way we will be able to
+    // avoid having filesystem collisions.  If this happens with a non-symlink
+    // entry, it'll just fail to unpack, but a symlink to a directory, using an
+    // 8.3 shortname or certain unicode attacks, can evade detection and lead
+    // to arbitrary writes to anywhere on the system.
+    if (entry.type === 'SymbolicLink') {
+      dropCache(this.dirCache)
+    } else if (entry.type !== 'Directory') {
+      pruneCache(this.dirCache, entry.absolute)
+    }
+  }
+
+  [CHECKFS2] (entry, fullyDone) {
+    this[PRUNECACHE](entry)
+
+    const done = er => {
+      this[PRUNECACHE](entry)
+      fullyDone(er)
+    }
+
+    const checkCwd = () => {
+      this[MKDIR](this.cwd, this.dmode, er => {
+        if (er) {
+          this[ONERROR](er, entry)
+          done()
+          return
+        }
+        this[CHECKED_CWD] = true
+        start()
+      })
+    }
+
+    const start = () => {
+      if (entry.absolute !== this.cwd) {
+        const parent = normPath(path.dirname(entry.absolute))
+        if (parent !== this.cwd) {
+          return this[MKDIR](parent, this.dmode, er => {
+            if (er) {
+              this[ONERROR](er, entry)
+              done()
+              return
+            }
+            afterMakeParent()
+          })
+        }
+      }
+      afterMakeParent()
+    }
+
+    const afterMakeParent = () => {
+      fs.lstat(entry.absolute, (lstatEr, st) => {
+        if (st && (this.keep || this.newer && st.mtime > entry.mtime)) {
+          this[SKIP](entry)
+          done()
+          return
+        }
+        if (lstatEr || this[ISREUSABLE](entry, st)) {
+          return this[MAKEFS](null, entry, done)
+        }
+
+        if (st.isDirectory()) {
+          if (entry.type === 'Directory') {
+            const needChmod = !this.noChmod &&
+              entry.mode &&
+              (st.mode & 0o7777) !== entry.mode
+            const afterChmod = er => this[MAKEFS](er, entry, done)
+            if (!needChmod) {
+              return afterChmod()
+            }
+            return fs.chmod(entry.absolute, entry.mode, afterChmod)
+          }
+          // Not a dir entry, have to remove it.
+          // NB: the only way to end up with an entry that is the cwd
+          // itself, in such a way that == does not detect, is a
+          // tricky windows absolute path with UNC or 8.3 parts (and
+          // preservePaths:true, or else it will have been stripped).
+          // In that case, the user has opted out of path protections
+          // explicitly, so if they blow away the cwd, c'est la vie.
+          if (entry.absolute !== this.cwd) {
+            return fs.rmdir(entry.absolute, er =>
+              this[MAKEFS](er, entry, done))
+          }
+        }
+
+        // not a dir, and not reusable
+        // don't remove if the cwd, we want that error
+        if (entry.absolute === this.cwd) {
+          return this[MAKEFS](null, entry, done)
+        }
+
+        unlinkFile(entry.absolute, er =>
+          this[MAKEFS](er, entry, done))
+      })
+    }
+
+    if (this[CHECKED_CWD]) {
+      start()
+    } else {
+      checkCwd()
+    }
+  }
+
+  [MAKEFS] (er, entry, done) {
+    if (er) {
+      this[ONERROR](er, entry)
+      done()
+      return
+    }
+
+    switch (entry.type) {
+      case 'File':
+      case 'OldFile':
+      case 'ContiguousFile':
+        return this[FILE](entry, done)
+
+      case 'Link':
+        return this[HARDLINK](entry, done)
+
+      case 'SymbolicLink':
+        return this[SYMLINK](entry, done)
+
+      case 'Directory':
+      case 'GNUDumpDir':
+        return this[DIRECTORY](entry, done)
+    }
+  }
+
+  [LINK] (entry, linkpath, link, done) {
+    // XXX: get the type ('symlink' or 'junction') for windows
+    fs[link](linkpath, entry.absolute, er => {
+      if (er) {
+        this[ONERROR](er, entry)
+      } else {
+        this[UNPEND]()
+        entry.resume()
+      }
+      done()
+    })
+  }
+}
+
+const callSync = fn => {
+  try {
+    return [null, fn()]
+  } catch (er) {
+    return [er, null]
+  }
+}
+class UnpackSync extends Unpack {
+  [MAKEFS] (er, entry) {
+    return super[MAKEFS](er, entry, () => {})
+  }
+
+  [CHECKFS] (entry) {
+    this[PRUNECACHE](entry)
+
+    if (!this[CHECKED_CWD]) {
+      const er = this[MKDIR](this.cwd, this.dmode)
+      if (er) {
+        return this[ONERROR](er, entry)
+      }
+      this[CHECKED_CWD] = true
+    }
+
+    // don't bother to make the parent if the current entry is the cwd,
+    // we've already checked it.
+    if (entry.absolute !== this.cwd) {
+      const parent = normPath(path.dirname(entry.absolute))
+      if (parent !== this.cwd) {
+        const mkParent = this[MKDIR](parent, this.dmode)
+        if (mkParent) {
+          return this[ONERROR](mkParent, entry)
+        }
+      }
+    }
+
+    const [lstatEr, st] = callSync(() => fs.lstatSync(entry.absolute))
+    if (st && (this.keep || this.newer && st.mtime > entry.mtime)) {
+      return this[SKIP](entry)
+    }
+
+    if (lstatEr || this[ISREUSABLE](entry, st)) {
+      return this[MAKEFS](null, entry)
+    }
+
+    if (st.isDirectory()) {
+      if (entry.type === 'Directory') {
+        const needChmod = !this.noChmod &&
+          entry.mode &&
+          (st.mode & 0o7777) !== entry.mode
+        const [er] = needChmod ? callSync(() => {
+          fs.chmodSync(entry.absolute, entry.mode)
+        }) : []
+        return this[MAKEFS](er, entry)
+      }
+      // not a dir entry, have to remove it
+      const [er] = callSync(() => fs.rmdirSync(entry.absolute))
+      this[MAKEFS](er, entry)
+    }
+
+    // not a dir, and not reusable.
+    // don't remove if it's the cwd, since we want that error.
+    const [er] = entry.absolute === this.cwd ? []
+      : callSync(() => unlinkFileSync(entry.absolute))
+    this[MAKEFS](er, entry)
+  }
+
+  [FILE] (entry, done) {
+    const mode = entry.mode & 0o7777 || this.fmode
+
+    const oner = er => {
+      let closeError
+      try {
+        fs.closeSync(fd)
+      } catch (e) {
+        closeError = e
+      }
+      if (er || closeError) {
+        this[ONERROR](er || closeError, entry)
+      }
+      done()
+    }
+
+    let fd
+    try {
+      fd = fs.openSync(entry.absolute, getFlag(entry.size), mode)
+    } catch (er) {
+      return oner(er)
+    }
+    const tx = this.transform ? this.transform(entry) || entry : entry
+    if (tx !== entry) {
+      tx.on('error', er => this[ONERROR](er, entry))
+      entry.pipe(tx)
+    }
+
+    tx.on('data', chunk => {
+      try {
+        fs.writeSync(fd, chunk, 0, chunk.length)
+      } catch (er) {
+        oner(er)
+      }
+    })
+
+    tx.on('end', _ => {
+      let er = null
+      // try both, falling futimes back to utimes
+      // if either fails, handle the first error
+      if (entry.mtime && !this.noMtime) {
+        const atime = entry.atime || new Date()
+        const mtime = entry.mtime
+        try {
+          fs.futimesSync(fd, atime, mtime)
+        } catch (futimeser) {
+          try {
+            fs.utimesSync(entry.absolute, atime, mtime)
+          } catch (utimeser) {
+            er = futimeser
+          }
+        }
+      }
+
+      if (this[DOCHOWN](entry)) {
+        const uid = this[UID](entry)
+        const gid = this[GID](entry)
+
+        try {
+          fs.fchownSync(fd, uid, gid)
+        } catch (fchowner) {
+          try {
+            fs.chownSync(entry.absolute, uid, gid)
+          } catch (chowner) {
+            er = er || fchowner
+          }
+        }
+      }
+
+      oner(er)
+    })
+  }
+
+  [DIRECTORY] (entry, done) {
+    const mode = entry.mode & 0o7777 || this.dmode
+    const er = this[MKDIR](entry.absolute, mode)
+    if (er) {
+      this[ONERROR](er, entry)
+      done()
+      return
+    }
+    if (entry.mtime && !this.noMtime) {
+      try {
+        fs.utimesSync(entry.absolute, entry.atime || new Date(), entry.mtime)
+      } catch (er) {}
+    }
+    if (this[DOCHOWN](entry)) {
+      try {
+        fs.chownSync(entry.absolute, this[UID](entry), this[GID](entry))
+      } catch (er) {}
+    }
+    done()
+    entry.resume()
+  }
+
+  [MKDIR] (dir, mode) {
+    try {
+      return mkdir.sync(normPath(dir), {
+        uid: this.uid,
+        gid: this.gid,
+        processUid: this.processUid,
+        processGid: this.processGid,
+        umask: this.processUmask,
+        preserve: this.preservePaths,
+        unlink: this.unlink,
+        cache: this.dirCache,
+        cwd: this.cwd,
+        mode: mode,
+      })
+    } catch (er) {
+      return er
+    }
+  }
+
+  [LINK] (entry, linkpath, link, done) {
+    try {
+      fs[link + 'Sync'](linkpath, entry.absolute)
+      done()
+      entry.resume()
+    } catch (er) {
+      return this[ONERROR](er, entry)
+    }
+  }
+}
+
+Unpack.Sync = UnpackSync
+module.exports = Unpack
diff --git a/server/node_modules/tar/lib/update.js b/server/node_modules/tar/lib/update.js
new file mode 100644
index 0000000..4d32854
--- /dev/null
+++ b/server/node_modules/tar/lib/update.js
@@ -0,0 +1,40 @@
+'use strict'
+
+// tar -u
+
+const hlo = require('./high-level-opt.js')
+const r = require('./replace.js')
+// just call tar.r with the filter and mtimeCache
+
+module.exports = (opt_, files, cb) => {
+  const opt = hlo(opt_)
+
+  if (!opt.file) {
+    throw new TypeError('file is required')
+  }
+
+  if (opt.gzip || opt.brotli || opt.file.endsWith('.br') || opt.file.endsWith('.tbr')) {
+    throw new TypeError('cannot append to compressed archives')
+  }
+
+  if (!files || !Array.isArray(files) || !files.length) {
+    throw new TypeError('no files or directories specified')
+  }
+
+  files = Array.from(files)
+
+  mtimeFilter(opt)
+  return r(opt, files, cb)
+}
+
+const mtimeFilter = opt => {
+  const filter = opt.filter
+
+  if (!opt.mtimeCache) {
+    opt.mtimeCache = new Map()
+  }
+
+  opt.filter = filter ? (path, stat) =>
+    filter(path, stat) && !(opt.mtimeCache.get(path) > stat.mtime)
+    : (path, stat) => !(opt.mtimeCache.get(path) > stat.mtime)
+}
diff --git a/server/node_modules/tar/lib/warn-mixin.js b/server/node_modules/tar/lib/warn-mixin.js
new file mode 100644
index 0000000..a940639
--- /dev/null
+++ b/server/node_modules/tar/lib/warn-mixin.js
@@ -0,0 +1,24 @@
+'use strict'
+module.exports = Base => class extends Base {
+  warn (code, message, data = {}) {
+    if (this.file) {
+      data.file = this.file
+    }
+    if (this.cwd) {
+      data.cwd = this.cwd
+    }
+    data.code = message instanceof Error && message.code || code
+    data.tarCode = code
+    if (!this.strict && data.recoverable !== false) {
+      if (message instanceof Error) {
+        data = Object.assign(message, data)
+        message = message.message
+      }
+      this.emit('warn', data.tarCode, message, data)
+    } else if (message instanceof Error) {
+      this.emit('error', Object.assign(message, data))
+    } else {
+      this.emit('error', Object.assign(new Error(`${code}: ${message}`), data))
+    }
+  }
+}
diff --git a/server/node_modules/tar/lib/winchars.js b/server/node_modules/tar/lib/winchars.js
new file mode 100644
index 0000000..ebcab4a
--- /dev/null
+++ b/server/node_modules/tar/lib/winchars.js
@@ -0,0 +1,23 @@
+'use strict'
+
+// When writing files on Windows, translate the characters to their
+// 0xf000 higher-encoded versions.
+
+const raw = [
+  '|',
+  '<',
+  '>',
+  '?',
+  ':',
+]
+
+const win = raw.map(char =>
+  String.fromCharCode(0xf000 + char.charCodeAt(0)))
+
+const toWin = new Map(raw.map((char, i) => [char, win[i]]))
+const toRaw = new Map(win.map((char, i) => [char, raw[i]]))
+
+module.exports = {
+  encode: s => raw.reduce((s, c) => s.split(c).join(toWin.get(c)), s),
+  decode: s => win.reduce((s, c) => s.split(c).join(toRaw.get(c)), s),
+}
diff --git a/server/node_modules/tar/lib/write-entry.js b/server/node_modules/tar/lib/write-entry.js
new file mode 100644
index 0000000..7d2f3eb
--- /dev/null
+++ b/server/node_modules/tar/lib/write-entry.js
@@ -0,0 +1,546 @@
+'use strict'
+const { Minipass } = require('minipass')
+const Pax = require('./pax.js')
+const Header = require('./header.js')
+const fs = require('fs')
+const path = require('path')
+const normPath = require('./normalize-windows-path.js')
+const stripSlash = require('./strip-trailing-slashes.js')
+
+const prefixPath = (path, prefix) => {
+  if (!prefix) {
+    return normPath(path)
+  }
+  path = normPath(path).replace(/^\.(\/|$)/, '')
+  return stripSlash(prefix) + '/' + path
+}
+
+const maxReadSize = 16 * 1024 * 1024
+const PROCESS = Symbol('process')
+const FILE = Symbol('file')
+const DIRECTORY = Symbol('directory')
+const SYMLINK = Symbol('symlink')
+const HARDLINK = Symbol('hardlink')
+const HEADER = Symbol('header')
+const READ = Symbol('read')
+const LSTAT = Symbol('lstat')
+const ONLSTAT = Symbol('onlstat')
+const ONREAD = Symbol('onread')
+const ONREADLINK = Symbol('onreadlink')
+const OPENFILE = Symbol('openfile')
+const ONOPENFILE = Symbol('onopenfile')
+const CLOSE = Symbol('close')
+const MODE = Symbol('mode')
+const AWAITDRAIN = Symbol('awaitDrain')
+const ONDRAIN = Symbol('ondrain')
+const PREFIX = Symbol('prefix')
+const HAD_ERROR = Symbol('hadError')
+const warner = require('./warn-mixin.js')
+const winchars = require('./winchars.js')
+const stripAbsolutePath = require('./strip-absolute-path.js')
+
+const modeFix = require('./mode-fix.js')
+
+const WriteEntry = warner(class WriteEntry extends Minipass {
+  constructor (p, opt) {
+    opt = opt || {}
+    super(opt)
+    if (typeof p !== 'string') {
+      throw new TypeError('path is required')
+    }
+    this.path = normPath(p)
+    // suppress atime, ctime, uid, gid, uname, gname
+    this.portable = !!opt.portable
+    // until node has builtin pwnam functions, this'll have to do
+    this.myuid = process.getuid && process.getuid() || 0
+    this.myuser = process.env.USER || ''
+    this.maxReadSize = opt.maxReadSize || maxReadSize
+    this.linkCache = opt.linkCache || new Map()
+    this.statCache = opt.statCache || new Map()
+    this.preservePaths = !!opt.preservePaths
+    this.cwd = normPath(opt.cwd || process.cwd())
+    this.strict = !!opt.strict
+    this.noPax = !!opt.noPax
+    this.noMtime = !!opt.noMtime
+    this.mtime = opt.mtime || null
+    this.prefix = opt.prefix ? normPath(opt.prefix) : null
+
+    this.fd = null
+    this.blockLen = null
+    this.blockRemain = null
+    this.buf = null
+    this.offset = null
+    this.length = null
+    this.pos = null
+    this.remain = null
+
+    if (typeof opt.onwarn === 'function') {
+      this.on('warn', opt.onwarn)
+    }
+
+    let pathWarn = false
+    if (!this.preservePaths) {
+      const [root, stripped] = stripAbsolutePath(this.path)
+      if (root) {
+        this.path = stripped
+        pathWarn = root
+      }
+    }
+
+    this.win32 = !!opt.win32 || process.platform === 'win32'
+    if (this.win32) {
+      // force the \ to / normalization, since we might not *actually*
+      // be on windows, but want \ to be considered a path separator.
+      this.path = winchars.decode(this.path.replace(/\\/g, '/'))
+      p = p.replace(/\\/g, '/')
+    }
+
+    this.absolute = normPath(opt.absolute || path.resolve(this.cwd, p))
+
+    if (this.path === '') {
+      this.path = './'
+    }
+
+    if (pathWarn) {
+      this.warn('TAR_ENTRY_INFO', `stripping ${pathWarn} from absolute path`, {
+        entry: this,
+        path: pathWarn + this.path,
+      })
+    }
+
+    if (this.statCache.has(this.absolute)) {
+      this[ONLSTAT](this.statCache.get(this.absolute))
+    } else {
+      this[LSTAT]()
+    }
+  }
+
+  emit (ev, ...data) {
+    if (ev === 'error') {
+      this[HAD_ERROR] = true
+    }
+    return super.emit(ev, ...data)
+  }
+
+  [LSTAT] () {
+    fs.lstat(this.absolute, (er, stat) => {
+      if (er) {
+        return this.emit('error', er)
+      }
+      this[ONLSTAT](stat)
+    })
+  }
+
+  [ONLSTAT] (stat) {
+    this.statCache.set(this.absolute, stat)
+    this.stat = stat
+    if (!stat.isFile()) {
+      stat.size = 0
+    }
+    this.type = getType(stat)
+    this.emit('stat', stat)
+    this[PROCESS]()
+  }
+
+  [PROCESS] () {
+    switch (this.type) {
+      case 'File': return this[FILE]()
+      case 'Directory': return this[DIRECTORY]()
+      case 'SymbolicLink': return this[SYMLINK]()
+      // unsupported types are ignored.
+      default: return this.end()
+    }
+  }
+
+  [MODE] (mode) {
+    return modeFix(mode, this.type === 'Directory', this.portable)
+  }
+
+  [PREFIX] (path) {
+    return prefixPath(path, this.prefix)
+  }
+
+  [HEADER] () {
+    if (this.type === 'Directory' && this.portable) {
+      this.noMtime = true
+    }
+
+    this.header = new Header({
+      path: this[PREFIX](this.path),
+      // only apply the prefix to hard links.
+      linkpath: this.type === 'Link' ? this[PREFIX](this.linkpath)
+      : this.linkpath,
+      // only the permissions and setuid/setgid/sticky bitflags
+      // not the higher-order bits that specify file type
+      mode: this[MODE](this.stat.mode),
+      uid: this.portable ? null : this.stat.uid,
+      gid: this.portable ? null : this.stat.gid,
+      size: this.stat.size,
+      mtime: this.noMtime ? null : this.mtime || this.stat.mtime,
+      type: this.type,
+      uname: this.portable ? null :
+      this.stat.uid === this.myuid ? this.myuser : '',
+      atime: this.portable ? null : this.stat.atime,
+      ctime: this.portable ? null : this.stat.ctime,
+    })
+
+    if (this.header.encode() && !this.noPax) {
+      super.write(new Pax({
+        atime: this.portable ? null : this.header.atime,
+        ctime: this.portable ? null : this.header.ctime,
+        gid: this.portable ? null : this.header.gid,
+        mtime: this.noMtime ? null : this.mtime || this.header.mtime,
+        path: this[PREFIX](this.path),
+        linkpath: this.type === 'Link' ? this[PREFIX](this.linkpath)
+        : this.linkpath,
+        size: this.header.size,
+        uid: this.portable ? null : this.header.uid,
+        uname: this.portable ? null : this.header.uname,
+        dev: this.portable ? null : this.stat.dev,
+        ino: this.portable ? null : this.stat.ino,
+        nlink: this.portable ? null : this.stat.nlink,
+      }).encode())
+    }
+    super.write(this.header.block)
+  }
+
+  [DIRECTORY] () {
+    if (this.path.slice(-1) !== '/') {
+      this.path += '/'
+    }
+    this.stat.size = 0
+    this[HEADER]()
+    this.end()
+  }
+
+  [SYMLINK] () {
+    fs.readlink(this.absolute, (er, linkpath) => {
+      if (er) {
+        return this.emit('error', er)
+      }
+      this[ONREADLINK](linkpath)
+    })
+  }
+
+  [ONREADLINK] (linkpath) {
+    this.linkpath = normPath(linkpath)
+    this[HEADER]()
+    this.end()
+  }
+
+  [HARDLINK] (linkpath) {
+    this.type = 'Link'
+    this.linkpath = normPath(path.relative(this.cwd, linkpath))
+    this.stat.size = 0
+    this[HEADER]()
+    this.end()
+  }
+
+  [FILE] () {
+    if (this.stat.nlink > 1) {
+      const linkKey = this.stat.dev + ':' + this.stat.ino
+      if (this.linkCache.has(linkKey)) {
+        const linkpath = this.linkCache.get(linkKey)
+        if (linkpath.indexOf(this.cwd) === 0) {
+          return this[HARDLINK](linkpath)
+        }
+      }
+      this.linkCache.set(linkKey, this.absolute)
+    }
+
+    this[HEADER]()
+    if (this.stat.size === 0) {
+      return this.end()
+    }
+
+    this[OPENFILE]()
+  }
+
+  [OPENFILE] () {
+    fs.open(this.absolute, 'r', (er, fd) => {
+      if (er) {
+        return this.emit('error', er)
+      }
+      this[ONOPENFILE](fd)
+    })
+  }
+
+  [ONOPENFILE] (fd) {
+    this.fd = fd
+    if (this[HAD_ERROR]) {
+      return this[CLOSE]()
+    }
+
+    this.blockLen = 512 * Math.ceil(this.stat.size / 512)
+    this.blockRemain = this.blockLen
+    const bufLen = Math.min(this.blockLen, this.maxReadSize)
+    this.buf = Buffer.allocUnsafe(bufLen)
+    this.offset = 0
+    this.pos = 0
+    this.remain = this.stat.size
+    this.length = this.buf.length
+    this[READ]()
+  }
+
+  [READ] () {
+    const { fd, buf, offset, length, pos } = this
+    fs.read(fd, buf, offset, length, pos, (er, bytesRead) => {
+      if (er) {
+        // ignoring the error from close(2) is a bad practice, but at
+        // this point we already have an error, don't need another one
+        return this[CLOSE](() => this.emit('error', er))
+      }
+      this[ONREAD](bytesRead)
+    })
+  }
+
+  [CLOSE] (cb) {
+    fs.close(this.fd, cb)
+  }
+
+  [ONREAD] (bytesRead) {
+    if (bytesRead <= 0 && this.remain > 0) {
+      const er = new Error('encountered unexpected EOF')
+      er.path = this.absolute
+      er.syscall = 'read'
+      er.code = 'EOF'
+      return this[CLOSE](() => this.emit('error', er))
+    }
+
+    if (bytesRead > this.remain) {
+      const er = new Error('did not encounter expected EOF')
+      er.path = this.absolute
+      er.syscall = 'read'
+      er.code = 'EOF'
+      return this[CLOSE](() => this.emit('error', er))
+    }
+
+    // null out the rest of the buffer, if we could fit the block padding
+    // at the end of this loop, we've incremented bytesRead and this.remain
+    // to be incremented up to the blockRemain level, as if we had expected
+    // to get a null-padded file, and read it until the end.  then we will
+    // decrement both remain and blockRemain by bytesRead, and know that we
+    // reached the expected EOF, without any null buffer to append.
+    if (bytesRead === this.remain) {
+      for (let i = bytesRead; i < this.length && bytesRead < this.blockRemain; i++) {
+        this.buf[i + this.offset] = 0
+        bytesRead++
+        this.remain++
+      }
+    }
+
+    const writeBuf = this.offset === 0 && bytesRead === this.buf.length ?
+      this.buf : this.buf.slice(this.offset, this.offset + bytesRead)
+
+    const flushed = this.write(writeBuf)
+    if (!flushed) {
+      this[AWAITDRAIN](() => this[ONDRAIN]())
+    } else {
+      this[ONDRAIN]()
+    }
+  }
+
+  [AWAITDRAIN] (cb) {
+    this.once('drain', cb)
+  }
+
+  write (writeBuf) {
+    if (this.blockRemain < writeBuf.length) {
+      const er = new Error('writing more data than expected')
+      er.path = this.absolute
+      return this.emit('error', er)
+    }
+    this.remain -= writeBuf.length
+    this.blockRemain -= writeBuf.length
+    this.pos += writeBuf.length
+    this.offset += writeBuf.length
+    return super.write(writeBuf)
+  }
+
+  [ONDRAIN] () {
+    if (!this.remain) {
+      if (this.blockRemain) {
+        super.write(Buffer.alloc(this.blockRemain))
+      }
+      return this[CLOSE](er => er ? this.emit('error', er) : this.end())
+    }
+
+    if (this.offset >= this.length) {
+      // if we only have a smaller bit left to read, alloc a smaller buffer
+      // otherwise, keep it the same length it was before.
+      this.buf = Buffer.allocUnsafe(Math.min(this.blockRemain, this.buf.length))
+      this.offset = 0
+    }
+    this.length = this.buf.length - this.offset
+    this[READ]()
+  }
+})
+
+class WriteEntrySync extends WriteEntry {
+  [LSTAT] () {
+    this[ONLSTAT](fs.lstatSync(this.absolute))
+  }
+
+  [SYMLINK] () {
+    this[ONREADLINK](fs.readlinkSync(this.absolute))
+  }
+
+  [OPENFILE] () {
+    this[ONOPENFILE](fs.openSync(this.absolute, 'r'))
+  }
+
+  [READ] () {
+    let threw = true
+    try {
+      const { fd, buf, offset, length, pos } = this
+      const bytesRead = fs.readSync(fd, buf, offset, length, pos)
+      this[ONREAD](bytesRead)
+      threw = false
+    } finally {
+      // ignoring the error from close(2) is a bad practice, but at
+      // this point we already have an error, don't need another one
+      if (threw) {
+        try {
+          this[CLOSE](() => {})
+        } catch (er) {}
+      }
+    }
+  }
+
+  [AWAITDRAIN] (cb) {
+    cb()
+  }
+
+  [CLOSE] (cb) {
+    fs.closeSync(this.fd)
+    cb()
+  }
+}
+
+const WriteEntryTar = warner(class WriteEntryTar extends Minipass {
+  constructor (readEntry, opt) {
+    opt = opt || {}
+    super(opt)
+    this.preservePaths = !!opt.preservePaths
+    this.portable = !!opt.portable
+    this.strict = !!opt.strict
+    this.noPax = !!opt.noPax
+    this.noMtime = !!opt.noMtime
+
+    this.readEntry = readEntry
+    this.type = readEntry.type
+    if (this.type === 'Directory' && this.portable) {
+      this.noMtime = true
+    }
+
+    this.prefix = opt.prefix || null
+
+    this.path = normPath(readEntry.path)
+    this.mode = this[MODE](readEntry.mode)
+    this.uid = this.portable ? null : readEntry.uid
+    this.gid = this.portable ? null : readEntry.gid
+    this.uname = this.portable ? null : readEntry.uname
+    this.gname = this.portable ? null : readEntry.gname
+    this.size = readEntry.size
+    this.mtime = this.noMtime ? null : opt.mtime || readEntry.mtime
+    this.atime = this.portable ? null : readEntry.atime
+    this.ctime = this.portable ? null : readEntry.ctime
+    this.linkpath = normPath(readEntry.linkpath)
+
+    if (typeof opt.onwarn === 'function') {
+      this.on('warn', opt.onwarn)
+    }
+
+    let pathWarn = false
+    if (!this.preservePaths) {
+      const [root, stripped] = stripAbsolutePath(this.path)
+      if (root) {
+        this.path = stripped
+        pathWarn = root
+      }
+    }
+
+    this.remain = readEntry.size
+    this.blockRemain = readEntry.startBlockSize
+
+    this.header = new Header({
+      path: this[PREFIX](this.path),
+      linkpath: this.type === 'Link' ? this[PREFIX](this.linkpath)
+      : this.linkpath,
+      // only the permissions and setuid/setgid/sticky bitflags
+      // not the higher-order bits that specify file type
+      mode: this.mode,
+      uid: this.portable ? null : this.uid,
+      gid: this.portable ? null : this.gid,
+      size: this.size,
+      mtime: this.noMtime ? null : this.mtime,
+      type: this.type,
+      uname: this.portable ? null : this.uname,
+      atime: this.portable ? null : this.atime,
+      ctime: this.portable ? null : this.ctime,
+    })
+
+    if (pathWarn) {
+      this.warn('TAR_ENTRY_INFO', `stripping ${pathWarn} from absolute path`, {
+        entry: this,
+        path: pathWarn + this.path,
+      })
+    }
+
+    if (this.header.encode() && !this.noPax) {
+      super.write(new Pax({
+        atime: this.portable ? null : this.atime,
+        ctime: this.portable ? null : this.ctime,
+        gid: this.portable ? null : this.gid,
+        mtime: this.noMtime ? null : this.mtime,
+        path: this[PREFIX](this.path),
+        linkpath: this.type === 'Link' ? this[PREFIX](this.linkpath)
+        : this.linkpath,
+        size: this.size,
+        uid: this.portable ? null : this.uid,
+        uname: this.portable ? null : this.uname,
+        dev: this.portable ? null : this.readEntry.dev,
+        ino: this.portable ? null : this.readEntry.ino,
+        nlink: this.portable ? null : this.readEntry.nlink,
+      }).encode())
+    }
+
+    super.write(this.header.block)
+    readEntry.pipe(this)
+  }
+
+  [PREFIX] (path) {
+    return prefixPath(path, this.prefix)
+  }
+
+  [MODE] (mode) {
+    return modeFix(mode, this.type === 'Directory', this.portable)
+  }
+
+  write (data) {
+    const writeLen = data.length
+    if (writeLen > this.blockRemain) {
+      throw new Error('writing more to entry than is appropriate')
+    }
+    this.blockRemain -= writeLen
+    return super.write(data)
+  }
+
+  end () {
+    if (this.blockRemain) {
+      super.write(Buffer.alloc(this.blockRemain))
+    }
+    return super.end()
+  }
+})
+
+WriteEntry.Sync = WriteEntrySync
+WriteEntry.Tar = WriteEntryTar
+
+const getType = stat =>
+  stat.isFile() ? 'File'
+  : stat.isDirectory() ? 'Directory'
+  : stat.isSymbolicLink() ? 'SymbolicLink'
+  : 'Unsupported'
+
+module.exports = WriteEntry
diff --git a/server/node_modules/tar/node_modules/.bin/mkdirp b/server/node_modules/tar/node_modules/.bin/mkdirp
new file mode 120000
index 0000000..017896c
--- /dev/null
+++ b/server/node_modules/tar/node_modules/.bin/mkdirp
@@ -0,0 +1 @@
+../mkdirp/bin/cmd.js
\ No newline at end of file
diff --git a/server/node_modules/tar/node_modules/chownr/LICENSE b/server/node_modules/tar/node_modules/chownr/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/tar/node_modules/chownr/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/tar/node_modules/chownr/README.md b/server/node_modules/tar/node_modules/chownr/README.md
new file mode 100644
index 0000000..70e9a54
--- /dev/null
+++ b/server/node_modules/tar/node_modules/chownr/README.md
@@ -0,0 +1,3 @@
+Like `chown -R`.
+
+Takes the same arguments as `fs.chown()`
diff --git a/server/node_modules/tar/node_modules/chownr/chownr.js b/server/node_modules/tar/node_modules/chownr/chownr.js
new file mode 100644
index 0000000..0d40932
--- /dev/null
+++ b/server/node_modules/tar/node_modules/chownr/chownr.js
@@ -0,0 +1,167 @@
+'use strict'
+const fs = require('fs')
+const path = require('path')
+
+/* istanbul ignore next */
+const LCHOWN = fs.lchown ? 'lchown' : 'chown'
+/* istanbul ignore next */
+const LCHOWNSYNC = fs.lchownSync ? 'lchownSync' : 'chownSync'
+
+/* istanbul ignore next */
+const needEISDIRHandled = fs.lchown &&
+  !process.version.match(/v1[1-9]+\./) &&
+  !process.version.match(/v10\.[6-9]/)
+
+const lchownSync = (path, uid, gid) => {
+  try {
+    return fs[LCHOWNSYNC](path, uid, gid)
+  } catch (er) {
+    if (er.code !== 'ENOENT')
+      throw er
+  }
+}
+
+/* istanbul ignore next */
+const chownSync = (path, uid, gid) => {
+  try {
+    return fs.chownSync(path, uid, gid)
+  } catch (er) {
+    if (er.code !== 'ENOENT')
+      throw er
+  }
+}
+
+/* istanbul ignore next */
+const handleEISDIR =
+  needEISDIRHandled ? (path, uid, gid, cb) => er => {
+    // Node prior to v10 had a very questionable implementation of
+    // fs.lchown, which would always try to call fs.open on a directory
+    // Fall back to fs.chown in those cases.
+    if (!er || er.code !== 'EISDIR')
+      cb(er)
+    else
+      fs.chown(path, uid, gid, cb)
+  }
+  : (_, __, ___, cb) => cb
+
+/* istanbul ignore next */
+const handleEISDirSync =
+  needEISDIRHandled ? (path, uid, gid) => {
+    try {
+      return lchownSync(path, uid, gid)
+    } catch (er) {
+      if (er.code !== 'EISDIR')
+        throw er
+      chownSync(path, uid, gid)
+    }
+  }
+  : (path, uid, gid) => lchownSync(path, uid, gid)
+
+// fs.readdir could only accept an options object as of node v6
+const nodeVersion = process.version
+let readdir = (path, options, cb) => fs.readdir(path, options, cb)
+let readdirSync = (path, options) => fs.readdirSync(path, options)
+/* istanbul ignore next */
+if (/^v4\./.test(nodeVersion))
+  readdir = (path, options, cb) => fs.readdir(path, cb)
+
+const chown = (cpath, uid, gid, cb) => {
+  fs[LCHOWN](cpath, uid, gid, handleEISDIR(cpath, uid, gid, er => {
+    // Skip ENOENT error
+    cb(er && er.code !== 'ENOENT' ? er : null)
+  }))
+}
+
+const chownrKid = (p, child, uid, gid, cb) => {
+  if (typeof child === 'string')
+    return fs.lstat(path.resolve(p, child), (er, stats) => {
+      // Skip ENOENT error
+      if (er)
+        return cb(er.code !== 'ENOENT' ? er : null)
+      stats.name = child
+      chownrKid(p, stats, uid, gid, cb)
+    })
+
+  if (child.isDirectory()) {
+    chownr(path.resolve(p, child.name), uid, gid, er => {
+      if (er)
+        return cb(er)
+      const cpath = path.resolve(p, child.name)
+      chown(cpath, uid, gid, cb)
+    })
+  } else {
+    const cpath = path.resolve(p, child.name)
+    chown(cpath, uid, gid, cb)
+  }
+}
+
+
+const chownr = (p, uid, gid, cb) => {
+  readdir(p, { withFileTypes: true }, (er, children) => {
+    // any error other than ENOTDIR or ENOTSUP means it's not readable,
+    // or doesn't exist.  give up.
+    if (er) {
+      if (er.code === 'ENOENT')
+        return cb()
+      else if (er.code !== 'ENOTDIR' && er.code !== 'ENOTSUP')
+        return cb(er)
+    }
+    if (er || !children.length)
+      return chown(p, uid, gid, cb)
+
+    let len = children.length
+    let errState = null
+    const then = er => {
+      if (errState)
+        return
+      if (er)
+        return cb(errState = er)
+      if (-- len === 0)
+        return chown(p, uid, gid, cb)
+    }
+
+    children.forEach(child => chownrKid(p, child, uid, gid, then))
+  })
+}
+
+const chownrKidSync = (p, child, uid, gid) => {
+  if (typeof child === 'string') {
+    try {
+      const stats = fs.lstatSync(path.resolve(p, child))
+      stats.name = child
+      child = stats
+    } catch (er) {
+      if (er.code === 'ENOENT')
+        return
+      else
+        throw er
+    }
+  }
+
+  if (child.isDirectory())
+    chownrSync(path.resolve(p, child.name), uid, gid)
+
+  handleEISDirSync(path.resolve(p, child.name), uid, gid)
+}
+
+const chownrSync = (p, uid, gid) => {
+  let children
+  try {
+    children = readdirSync(p, { withFileTypes: true })
+  } catch (er) {
+    if (er.code === 'ENOENT')
+      return
+    else if (er.code === 'ENOTDIR' || er.code === 'ENOTSUP')
+      return handleEISDirSync(p, uid, gid)
+    else
+      throw er
+  }
+
+  if (children && children.length)
+    children.forEach(child => chownrKidSync(p, child, uid, gid))
+
+  return handleEISDirSync(p, uid, gid)
+}
+
+module.exports = chownr
+chownr.sync = chownrSync
diff --git a/server/node_modules/tar/node_modules/chownr/package.json b/server/node_modules/tar/node_modules/chownr/package.json
new file mode 100644
index 0000000..5b0214c
--- /dev/null
+++ b/server/node_modules/tar/node_modules/chownr/package.json
@@ -0,0 +1,32 @@
+{
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "name": "chownr",
+  "description": "like `chown -R`",
+  "version": "2.0.0",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/isaacs/chownr.git"
+  },
+  "main": "chownr.js",
+  "files": [
+    "chownr.js"
+  ],
+  "devDependencies": {
+    "mkdirp": "0.3",
+    "rimraf": "^2.7.1",
+    "tap": "^14.10.6"
+  },
+  "tap": {
+    "check-coverage": true
+  },
+  "scripts": {
+    "test": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublishOnly": "git push origin --follow-tags"
+  },
+  "license": "ISC",
+  "engines": {
+    "node": ">=10"
+  }
+}
diff --git a/server/node_modules/tar/node_modules/minipass/LICENSE b/server/node_modules/tar/node_modules/minipass/LICENSE
new file mode 100644
index 0000000..97f8e32
--- /dev/null
+++ b/server/node_modules/tar/node_modules/minipass/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) 2017-2023 npm, Inc., Isaac Z. Schlueter, and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/tar/node_modules/minipass/README.md b/server/node_modules/tar/node_modules/minipass/README.md
new file mode 100644
index 0000000..6108809
--- /dev/null
+++ b/server/node_modules/tar/node_modules/minipass/README.md
@@ -0,0 +1,769 @@
+# minipass
+
+A _very_ minimal implementation of a [PassThrough
+stream](https://nodejs.org/api/stream.html#stream_class_stream_passthrough)
+
+[It's very
+fast](https://docs.google.com/spreadsheets/d/1K_HR5oh3r80b8WVMWCPPjfuWXUgfkmhlX7FGI6JJ8tY/edit?usp=sharing)
+for objects, strings, and buffers.
+
+Supports `pipe()`ing (including multi-`pipe()` and backpressure
+transmission), buffering data until either a `data` event handler
+or `pipe()` is added (so you don't lose the first chunk), and
+most other cases where PassThrough is a good idea.
+
+There is a `read()` method, but it's much more efficient to
+consume data from this stream via `'data'` events or by calling
+`pipe()` into some other stream. Calling `read()` requires the
+buffer to be flattened in some cases, which requires copying
+memory.
+
+If you set `objectMode: true` in the options, then whatever is
+written will be emitted. Otherwise, it'll do a minimal amount of
+Buffer copying to ensure proper Streams semantics when `read(n)`
+is called.
+
+`objectMode` can also be set by doing `stream.objectMode = true`,
+or by writing any non-string/non-buffer data. `objectMode` cannot
+be set to false once it is set.
+
+This is not a `through` or `through2` stream. It doesn't
+transform the data, it just passes it right through. If you want
+to transform the data, extend the class, and override the
+`write()` method. Once you're done transforming the data however
+you want, call `super.write()` with the transform output.
+
+For some examples of streams that extend Minipass in various
+ways, check out:
+
+- [minizlib](http://npm.im/minizlib)
+- [fs-minipass](http://npm.im/fs-minipass)
+- [tar](http://npm.im/tar)
+- [minipass-collect](http://npm.im/minipass-collect)
+- [minipass-flush](http://npm.im/minipass-flush)
+- [minipass-pipeline](http://npm.im/minipass-pipeline)
+- [tap](http://npm.im/tap)
+- [tap-parser](http://npm.im/tap-parser)
+- [treport](http://npm.im/treport)
+- [minipass-fetch](http://npm.im/minipass-fetch)
+- [pacote](http://npm.im/pacote)
+- [make-fetch-happen](http://npm.im/make-fetch-happen)
+- [cacache](http://npm.im/cacache)
+- [ssri](http://npm.im/ssri)
+- [npm-registry-fetch](http://npm.im/npm-registry-fetch)
+- [minipass-json-stream](http://npm.im/minipass-json-stream)
+- [minipass-sized](http://npm.im/minipass-sized)
+
+## Differences from Node.js Streams
+
+There are several things that make Minipass streams different
+from (and in some ways superior to) Node.js core streams.
+
+Please read these caveats if you are familiar with node-core
+streams and intend to use Minipass streams in your programs.
+
+You can avoid most of these differences entirely (for a very
+small performance penalty) by setting `{async: true}` in the
+constructor options.
+
+### Timing
+
+Minipass streams are designed to support synchronous use-cases.
+Thus, data is emitted as soon as it is available, always. It is
+buffered until read, but no longer. Another way to look at it is
+that Minipass streams are exactly as synchronous as the logic
+that writes into them.
+
+This can be surprising if your code relies on
+`PassThrough.write()` always providing data on the next tick
+rather than the current one, or being able to call `resume()` and
+not have the entire buffer disappear immediately.
+
+However, without this synchronicity guarantee, there would be no
+way for Minipass to achieve the speeds it does, or support the
+synchronous use cases that it does. Simply put, waiting takes
+time.
+
+This non-deferring approach makes Minipass streams much easier to
+reason about, especially in the context of Promises and other
+flow-control mechanisms.
+
+Example:
+
+```js
+// hybrid module, either works
+import { Minipass } from 'minipass'
+// or:
+const { Minipass } = require('minipass')
+
+const stream = new Minipass()
+stream.on('data', () => console.log('data event'))
+console.log('before write')
+stream.write('hello')
+console.log('after write')
+// output:
+// before write
+// data event
+// after write
+```
+
+### Exception: Async Opt-In
+
+If you wish to have a Minipass stream with behavior that more
+closely mimics Node.js core streams, you can set the stream in
+async mode either by setting `async: true` in the constructor
+options, or by setting `stream.async = true` later on.
+
+```js
+// hybrid module, either works
+import { Minipass } from 'minipass'
+// or:
+const { Minipass } = require('minipass')
+
+const asyncStream = new Minipass({ async: true })
+asyncStream.on('data', () => console.log('data event'))
+console.log('before write')
+asyncStream.write('hello')
+console.log('after write')
+// output:
+// before write
+// after write
+// data event <-- this is deferred until the next tick
+```
+
+Switching _out_ of async mode is unsafe, as it could cause data
+corruption, and so is not enabled. Example:
+
+```js
+import { Minipass } from 'minipass'
+const stream = new Minipass({ encoding: 'utf8' })
+stream.on('data', chunk => console.log(chunk))
+stream.async = true
+console.log('before writes')
+stream.write('hello')
+setStreamSyncAgainSomehow(stream) // <-- this doesn't actually exist!
+stream.write('world')
+console.log('after writes')
+// hypothetical output would be:
+// before writes
+// world
+// after writes
+// hello
+// NOT GOOD!
+```
+
+To avoid this problem, once set into async mode, any attempt to
+make the stream sync again will be ignored.
+
+```js
+const { Minipass } = require('minipass')
+const stream = new Minipass({ encoding: 'utf8' })
+stream.on('data', chunk => console.log(chunk))
+stream.async = true
+console.log('before writes')
+stream.write('hello')
+stream.async = false // <-- no-op, stream already async
+stream.write('world')
+console.log('after writes')
+// actual output:
+// before writes
+// after writes
+// hello
+// world
+```
+
+### No High/Low Water Marks
+
+Node.js core streams will optimistically fill up a buffer,
+returning `true` on all writes until the limit is hit, even if
+the data has nowhere to go. Then, they will not attempt to draw
+more data in until the buffer size dips below a minimum value.
+
+Minipass streams are much simpler. The `write()` method will
+return `true` if the data has somewhere to go (which is to say,
+given the timing guarantees, that the data is already there by
+the time `write()` returns).
+
+If the data has nowhere to go, then `write()` returns false, and
+the data sits in a buffer, to be drained out immediately as soon
+as anyone consumes it.
+
+Since nothing is ever buffered unnecessarily, there is much less
+copying data, and less bookkeeping about buffer capacity levels.
+
+### Hazards of Buffering (or: Why Minipass Is So Fast)
+
+Since data written to a Minipass stream is immediately written
+all the way through the pipeline, and `write()` always returns
+true/false based on whether the data was fully flushed,
+backpressure is communicated immediately to the upstream caller.
+This minimizes buffering.
+
+Consider this case:
+
+```js
+const { PassThrough } = require('stream')
+const p1 = new PassThrough({ highWaterMark: 1024 })
+const p2 = new PassThrough({ highWaterMark: 1024 })
+const p3 = new PassThrough({ highWaterMark: 1024 })
+const p4 = new PassThrough({ highWaterMark: 1024 })
+
+p1.pipe(p2).pipe(p3).pipe(p4)
+p4.on('data', () => console.log('made it through'))
+
+// this returns false and buffers, then writes to p2 on next tick (1)
+// p2 returns false and buffers, pausing p1, then writes to p3 on next tick (2)
+// p3 returns false and buffers, pausing p2, then writes to p4 on next tick (3)
+// p4 returns false and buffers, pausing p3, then emits 'data' and 'drain'
+// on next tick (4)
+// p3 sees p4's 'drain' event, and calls resume(), emitting 'resume' and
+// 'drain' on next tick (5)
+// p2 sees p3's 'drain', calls resume(), emits 'resume' and 'drain' on next tick (6)
+// p1 sees p2's 'drain', calls resume(), emits 'resume' and 'drain' on next
+// tick (7)
+
+p1.write(Buffer.alloc(2048)) // returns false
+```
+
+Along the way, the data was buffered and deferred at each stage,
+and multiple event deferrals happened, for an unblocked pipeline
+where it was perfectly safe to write all the way through!
+
+Furthermore, setting a `highWaterMark` of `1024` might lead
+someone reading the code to think an advisory maximum of 1KiB is
+being set for the pipeline. However, the actual advisory
+buffering level is the _sum_ of `highWaterMark` values, since
+each one has its own bucket.
+
+Consider the Minipass case:
+
+```js
+const m1 = new Minipass()
+const m2 = new Minipass()
+const m3 = new Minipass()
+const m4 = new Minipass()
+
+m1.pipe(m2).pipe(m3).pipe(m4)
+m4.on('data', () => console.log('made it through'))
+
+// m1 is flowing, so it writes the data to m2 immediately
+// m2 is flowing, so it writes the data to m3 immediately
+// m3 is flowing, so it writes the data to m4 immediately
+// m4 is flowing, so it fires the 'data' event immediately, returns true
+// m4's write returned true, so m3 is still flowing, returns true
+// m3's write returned true, so m2 is still flowing, returns true
+// m2's write returned true, so m1 is still flowing, returns true
+// No event deferrals or buffering along the way!
+
+m1.write(Buffer.alloc(2048)) // returns true
+```
+
+It is extremely unlikely that you _don't_ want to buffer any data
+written, or _ever_ buffer data that can be flushed all the way
+through. Neither node-core streams nor Minipass ever fail to
+buffer written data, but node-core streams do a lot of
+unnecessary buffering and pausing.
+
+As always, the faster implementation is the one that does less
+stuff and waits less time to do it.
+
+### Immediately emit `end` for empty streams (when not paused)
+
+If a stream is not paused, and `end()` is called before writing
+any data into it, then it will emit `end` immediately.
+
+If you have logic that occurs on the `end` event which you don't
+want to potentially happen immediately (for example, closing file
+descriptors, moving on to the next entry in an archive parse
+stream, etc.) then be sure to call `stream.pause()` on creation,
+and then `stream.resume()` once you are ready to respond to the
+`end` event.
+
+However, this is _usually_ not a problem because:
+
+### Emit `end` When Asked
+
+One hazard of immediately emitting `'end'` is that you may not
+yet have had a chance to add a listener. In order to avoid this
+hazard, Minipass streams safely re-emit the `'end'` event if a
+new listener is added after `'end'` has been emitted.
+
+Ie, if you do `stream.on('end', someFunction)`, and the stream
+has already emitted `end`, then it will call the handler right
+away. (You can think of this somewhat like attaching a new
+`.then(fn)` to a previously-resolved Promise.)
+
+To prevent calling handlers multiple times who would not expect
+multiple ends to occur, all listeners are removed from the
+`'end'` event whenever it is emitted.
+
+### Emit `error` When Asked
+
+The most recent error object passed to the `'error'` event is
+stored on the stream. If a new `'error'` event handler is added,
+and an error was previously emitted, then the event handler will
+be called immediately (or on `process.nextTick` in the case of
+async streams).
+
+This makes it much more difficult to end up trying to interact
+with a broken stream, if the error handler is added after an
+error was previously emitted.
+
+### Impact of "immediate flow" on Tee-streams
+
+A "tee stream" is a stream piping to multiple destinations:
+
+```js
+const tee = new Minipass()
+t.pipe(dest1)
+t.pipe(dest2)
+t.write('foo') // goes to both destinations
+```
+
+Since Minipass streams _immediately_ process any pending data
+through the pipeline when a new pipe destination is added, this
+can have surprising effects, especially when a stream comes in
+from some other function and may or may not have data in its
+buffer.
+
+```js
+// WARNING! WILL LOSE DATA!
+const src = new Minipass()
+src.write('foo')
+src.pipe(dest1) // 'foo' chunk flows to dest1 immediately, and is gone
+src.pipe(dest2) // gets nothing!
+```
+
+One solution is to create a dedicated tee-stream junction that
+pipes to both locations, and then pipe to _that_ instead.
+
+```js
+// Safe example: tee to both places
+const src = new Minipass()
+src.write('foo')
+const tee = new Minipass()
+tee.pipe(dest1)
+tee.pipe(dest2)
+src.pipe(tee) // tee gets 'foo', pipes to both locations
+```
+
+The same caveat applies to `on('data')` event listeners. The
+first one added will _immediately_ receive all of the data,
+leaving nothing for the second:
+
+```js
+// WARNING! WILL LOSE DATA!
+const src = new Minipass()
+src.write('foo')
+src.on('data', handler1) // receives 'foo' right away
+src.on('data', handler2) // nothing to see here!
+```
+
+Using a dedicated tee-stream can be used in this case as well:
+
+```js
+// Safe example: tee to both data handlers
+const src = new Minipass()
+src.write('foo')
+const tee = new Minipass()
+tee.on('data', handler1)
+tee.on('data', handler2)
+src.pipe(tee)
+```
+
+All of the hazards in this section are avoided by setting `{
+async: true }` in the Minipass constructor, or by setting
+`stream.async = true` afterwards. Note that this does add some
+overhead, so should only be done in cases where you are willing
+to lose a bit of performance in order to avoid having to refactor
+program logic.
+
+## USAGE
+
+It's a stream! Use it like a stream and it'll most likely do what
+you want.
+
+```js
+import { Minipass } from 'minipass'
+const mp = new Minipass(options) // optional: { encoding, objectMode }
+mp.write('foo')
+mp.pipe(someOtherStream)
+mp.end('bar')
+```
+
+### OPTIONS
+
+- `encoding` How would you like the data coming _out_ of the
+  stream to be encoded? Accepts any values that can be passed to
+  `Buffer.toString()`.
+- `objectMode` Emit data exactly as it comes in. This will be
+  flipped on by default if you write() something other than a
+  string or Buffer at any point. Setting `objectMode: true` will
+  prevent setting any encoding value.
+- `async` Defaults to `false`. Set to `true` to defer data
+  emission until next tick. This reduces performance slightly,
+  but makes Minipass streams use timing behavior closer to Node
+  core streams. See [Timing](#timing) for more details.
+- `signal` An `AbortSignal` that will cause the stream to unhook
+  itself from everything and become as inert as possible. Note
+  that providing a `signal` parameter will make `'error'` events
+  no longer throw if they are unhandled, but they will still be
+  emitted to handlers if any are attached.
+
+### API
+
+Implements the user-facing portions of Node.js's `Readable` and
+`Writable` streams.
+
+### Methods
+
+- `write(chunk, [encoding], [callback])` - Put data in. (Note
+  that, in the base Minipass class, the same data will come out.)
+  Returns `false` if the stream will buffer the next write, or
+  true if it's still in "flowing" mode.
+- `end([chunk, [encoding]], [callback])` - Signal that you have
+  no more data to write. This will queue an `end` event to be
+  fired when all the data has been consumed.
+- `setEncoding(encoding)` - Set the encoding for data coming of
+  the stream. This can only be done once.
+- `pause()` - No more data for a while, please. This also
+  prevents `end` from being emitted for empty streams until the
+  stream is resumed.
+- `resume()` - Resume the stream. If there's data in the buffer,
+  it is all discarded. Any buffered events are immediately
+  emitted.
+- `pipe(dest)` - Send all output to the stream provided. When
+  data is emitted, it is immediately written to any and all pipe
+  destinations. (Or written on next tick in `async` mode.)
+- `unpipe(dest)` - Stop piping to the destination stream. This is
+  immediate, meaning that any asynchronously queued data will
+  _not_ make it to the destination when running in `async` mode.
+  - `options.end` - Boolean, end the destination stream when the
+    source stream ends. Default `true`.
+  - `options.proxyErrors` - Boolean, proxy `error` events from
+    the source stream to the destination stream. Note that errors
+    are _not_ proxied after the pipeline terminates, either due
+    to the source emitting `'end'` or manually unpiping with
+    `src.unpipe(dest)`. Default `false`.
+- `on(ev, fn)`, `emit(ev, fn)` - Minipass streams are
+  EventEmitters. Some events are given special treatment,
+  however. (See below under "events".)
+- `promise()` - Returns a Promise that resolves when the stream
+  emits `end`, or rejects if the stream emits `error`.
+- `collect()` - Return a Promise that resolves on `end` with an
+  array containing each chunk of data that was emitted, or
+  rejects if the stream emits `error`. Note that this consumes
+  the stream data.
+- `concat()` - Same as `collect()`, but concatenates the data
+  into a single Buffer object. Will reject the returned promise
+  if the stream is in objectMode, or if it goes into objectMode
+  by the end of the data.
+- `read(n)` - Consume `n` bytes of data out of the buffer. If `n`
+  is not provided, then consume all of it. If `n` bytes are not
+  available, then it returns null. **Note** consuming streams in
+  this way is less efficient, and can lead to unnecessary Buffer
+  copying.
+- `destroy([er])` - Destroy the stream. If an error is provided,
+  then an `'error'` event is emitted. If the stream has a
+  `close()` method, and has not emitted a `'close'` event yet,
+  then `stream.close()` will be called. Any Promises returned by
+  `.promise()`, `.collect()` or `.concat()` will be rejected.
+  After being destroyed, writing to the stream will emit an
+  error. No more data will be emitted if the stream is destroyed,
+  even if it was previously buffered.
+
+### Properties
+
+- `bufferLength` Read-only. Total number of bytes buffered, or in
+  the case of objectMode, the total number of objects.
+- `encoding` The encoding that has been set. (Setting this is
+  equivalent to calling `setEncoding(enc)` and has the same
+  prohibition against setting multiple times.)
+- `flowing` Read-only. Boolean indicating whether a chunk written
+  to the stream will be immediately emitted.
+- `emittedEnd` Read-only. Boolean indicating whether the end-ish
+  events (ie, `end`, `prefinish`, `finish`) have been emitted.
+  Note that listening on any end-ish event will immediateyl
+  re-emit it if it has already been emitted.
+- `writable` Whether the stream is writable. Default `true`. Set
+  to `false` when `end()`
+- `readable` Whether the stream is readable. Default `true`.
+- `pipes` An array of Pipe objects referencing streams that this
+  stream is piping into.
+- `destroyed` A getter that indicates whether the stream was
+  destroyed.
+- `paused` True if the stream has been explicitly paused,
+  otherwise false.
+- `objectMode` Indicates whether the stream is in `objectMode`.
+  Once set to `true`, it cannot be set to `false`.
+- `aborted` Readonly property set when the `AbortSignal`
+  dispatches an `abort` event.
+
+### Events
+
+- `data` Emitted when there's data to read. Argument is the data
+  to read. This is never emitted while not flowing. If a listener
+  is attached, that will resume the stream.
+- `end` Emitted when there's no more data to read. This will be
+  emitted immediately for empty streams when `end()` is called.
+  If a listener is attached, and `end` was already emitted, then
+  it will be emitted again. All listeners are removed when `end`
+  is emitted.
+- `prefinish` An end-ish event that follows the same logic as
+  `end` and is emitted in the same conditions where `end` is
+  emitted. Emitted after `'end'`.
+- `finish` An end-ish event that follows the same logic as `end`
+  and is emitted in the same conditions where `end` is emitted.
+  Emitted after `'prefinish'`.
+- `close` An indication that an underlying resource has been
+  released. Minipass does not emit this event, but will defer it
+  until after `end` has been emitted, since it throws off some
+  stream libraries otherwise.
+- `drain` Emitted when the internal buffer empties, and it is
+  again suitable to `write()` into the stream.
+- `readable` Emitted when data is buffered and ready to be read
+  by a consumer.
+- `resume` Emitted when stream changes state from buffering to
+  flowing mode. (Ie, when `resume` is called, `pipe` is called,
+  or a `data` event listener is added.)
+
+### Static Methods
+
+- `Minipass.isStream(stream)` Returns `true` if the argument is a
+  stream, and false otherwise. To be considered a stream, the
+  object must be either an instance of Minipass, or an
+  EventEmitter that has either a `pipe()` method, or both
+  `write()` and `end()` methods. (Pretty much any stream in
+  node-land will return `true` for this.)
+
+## EXAMPLES
+
+Here are some examples of things you can do with Minipass
+streams.
+
+### simple "are you done yet" promise
+
+```js
+mp.promise().then(
+  () => {
+    // stream is finished
+  },
+  er => {
+    // stream emitted an error
+  }
+)
+```
+
+### collecting
+
+```js
+mp.collect().then(all => {
+  // all is an array of all the data emitted
+  // encoding is supported in this case, so
+  // so the result will be a collection of strings if
+  // an encoding is specified, or buffers/objects if not.
+  //
+  // In an async function, you may do
+  // const data = await stream.collect()
+})
+```
+
+### collecting into a single blob
+
+This is a bit slower because it concatenates the data into one
+chunk for you, but if you're going to do it yourself anyway, it's
+convenient this way:
+
+```js
+mp.concat().then(onebigchunk => {
+  // onebigchunk is a string if the stream
+  // had an encoding set, or a buffer otherwise.
+})
+```
+
+### iteration
+
+You can iterate over streams synchronously or asynchronously in
+platforms that support it.
+
+Synchronous iteration will end when the currently available data
+is consumed, even if the `end` event has not been reached. In
+string and buffer mode, the data is concatenated, so unless
+multiple writes are occurring in the same tick as the `read()`,
+sync iteration loops will generally only have a single iteration.
+
+To consume chunks in this way exactly as they have been written,
+with no flattening, create the stream with the `{ objectMode:
+true }` option.
+
+```js
+const mp = new Minipass({ objectMode: true })
+mp.write('a')
+mp.write('b')
+for (let letter of mp) {
+  console.log(letter) // a, b
+}
+mp.write('c')
+mp.write('d')
+for (let letter of mp) {
+  console.log(letter) // c, d
+}
+mp.write('e')
+mp.end()
+for (let letter of mp) {
+  console.log(letter) // e
+}
+for (let letter of mp) {
+  console.log(letter) // nothing
+}
+```
+
+Asynchronous iteration will continue until the end event is reached,
+consuming all of the data.
+
+```js
+const mp = new Minipass({ encoding: 'utf8' })
+
+// some source of some data
+let i = 5
+const inter = setInterval(() => {
+  if (i-- > 0) mp.write(Buffer.from('foo\n', 'utf8'))
+  else {
+    mp.end()
+    clearInterval(inter)
+  }
+}, 100)
+
+// consume the data with asynchronous iteration
+async function consume() {
+  for await (let chunk of mp) {
+    console.log(chunk)
+  }
+  return 'ok'
+}
+
+consume().then(res => console.log(res))
+// logs `foo\n` 5 times, and then `ok`
+```
+
+### subclass that `console.log()`s everything written into it
+
+```js
+class Logger extends Minipass {
+  write(chunk, encoding, callback) {
+    console.log('WRITE', chunk, encoding)
+    return super.write(chunk, encoding, callback)
+  }
+  end(chunk, encoding, callback) {
+    console.log('END', chunk, encoding)
+    return super.end(chunk, encoding, callback)
+  }
+}
+
+someSource.pipe(new Logger()).pipe(someDest)
+```
+
+### same thing, but using an inline anonymous class
+
+```js
+// js classes are fun
+someSource
+  .pipe(
+    new (class extends Minipass {
+      emit(ev, ...data) {
+        // let's also log events, because debugging some weird thing
+        console.log('EMIT', ev)
+        return super.emit(ev, ...data)
+      }
+      write(chunk, encoding, callback) {
+        console.log('WRITE', chunk, encoding)
+        return super.write(chunk, encoding, callback)
+      }
+      end(chunk, encoding, callback) {
+        console.log('END', chunk, encoding)
+        return super.end(chunk, encoding, callback)
+      }
+    })()
+  )
+  .pipe(someDest)
+```
+
+### subclass that defers 'end' for some reason
+
+```js
+class SlowEnd extends Minipass {
+  emit(ev, ...args) {
+    if (ev === 'end') {
+      console.log('going to end, hold on a sec')
+      setTimeout(() => {
+        console.log('ok, ready to end now')
+        super.emit('end', ...args)
+      }, 100)
+    } else {
+      return super.emit(ev, ...args)
+    }
+  }
+}
+```
+
+### transform that creates newline-delimited JSON
+
+```js
+class NDJSONEncode extends Minipass {
+  write(obj, cb) {
+    try {
+      // JSON.stringify can throw, emit an error on that
+      return super.write(JSON.stringify(obj) + '\n', 'utf8', cb)
+    } catch (er) {
+      this.emit('error', er)
+    }
+  }
+  end(obj, cb) {
+    if (typeof obj === 'function') {
+      cb = obj
+      obj = undefined
+    }
+    if (obj !== undefined) {
+      this.write(obj)
+    }
+    return super.end(cb)
+  }
+}
+```
+
+### transform that parses newline-delimited JSON
+
+```js
+class NDJSONDecode extends Minipass {
+  constructor (options) {
+    // always be in object mode, as far as Minipass is concerned
+    super({ objectMode: true })
+    this._jsonBuffer = ''
+  }
+  write (chunk, encoding, cb) {
+    if (typeof chunk === 'string' &&
+        typeof encoding === 'string' &&
+        encoding !== 'utf8') {
+      chunk = Buffer.from(chunk, encoding).toString()
+    } else if (Buffer.isBuffer(chunk)) {
+      chunk = chunk.toString()
+    }
+    if (typeof encoding === 'function') {
+      cb = encoding
+    }
+    const jsonData = (this._jsonBuffer + chunk).split('\n')
+    this._jsonBuffer = jsonData.pop()
+    for (let i = 0; i < jsonData.length; i++) {
+      try {
+        // JSON.parse can throw, emit an error on that
+        super.write(JSON.parse(jsonData[i]))
+      } catch (er) {
+        this.emit('error', er)
+        continue
+      }
+    }
+    if (cb)
+      cb()
+  }
+}
+```
diff --git a/server/node_modules/tar/node_modules/minipass/index.d.ts b/server/node_modules/tar/node_modules/minipass/index.d.ts
new file mode 100644
index 0000000..86851f9
--- /dev/null
+++ b/server/node_modules/tar/node_modules/minipass/index.d.ts
@@ -0,0 +1,152 @@
+/// <reference types="node" />
+
+// Note: marking anything protected or private in the exported
+// class will limit Minipass's ability to be used as the base
+// for mixin classes.
+import { EventEmitter } from 'events'
+import { Stream } from 'stream'
+
+export namespace Minipass {
+  export type Encoding = BufferEncoding | 'buffer' | null
+
+  export interface Writable extends EventEmitter {
+    end(): any
+    write(chunk: any, ...args: any[]): any
+  }
+
+  export interface Readable extends EventEmitter {
+    pause(): any
+    resume(): any
+    pipe(): any
+  }
+
+  export type DualIterable<T> = Iterable<T> & AsyncIterable<T>
+
+  export type ContiguousData =
+    | Buffer
+    | ArrayBufferLike
+    | ArrayBufferView
+    | string
+
+  export type BufferOrString = Buffer | string
+
+  export interface SharedOptions {
+    async?: boolean
+    signal?: AbortSignal
+  }
+
+  export interface StringOptions extends SharedOptions {
+    encoding: BufferEncoding
+    objectMode?: boolean
+  }
+
+  export interface BufferOptions extends SharedOptions {
+    encoding?: null | 'buffer'
+    objectMode?: boolean
+  }
+
+  export interface ObjectModeOptions extends SharedOptions {
+    objectMode: true
+  }
+
+  export interface PipeOptions {
+    end?: boolean
+    proxyErrors?: boolean
+  }
+
+  export type Options<T> = T extends string
+    ? StringOptions
+    : T extends Buffer
+    ? BufferOptions
+    : ObjectModeOptions
+}
+
+export class Minipass<
+    RType extends any = Buffer,
+    WType extends any = RType extends Minipass.BufferOrString
+      ? Minipass.ContiguousData
+      : RType
+  >
+  extends Stream
+  implements Minipass.DualIterable<RType>
+{
+  static isStream(stream: any): stream is Minipass.Readable | Minipass.Writable
+
+  readonly bufferLength: number
+  readonly flowing: boolean
+  readonly writable: boolean
+  readonly readable: boolean
+  readonly aborted: boolean
+  readonly paused: boolean
+  readonly emittedEnd: boolean
+  readonly destroyed: boolean
+
+  /**
+   * Technically writable, but mutating it can change the type,
+   * so is not safe to do in TypeScript.
+   */
+  readonly objectMode: boolean
+  async: boolean
+
+  /**
+   * Note: encoding is not actually read-only, and setEncoding(enc)
+   * exists. However, this type definition will insist that TypeScript
+   * programs declare the type of a Minipass stream up front, and if
+   * that type is string, then an encoding MUST be set in the ctor. If
+   * the type is Buffer, then the encoding must be missing, or set to
+   * 'buffer' or null. If the type is anything else, then objectMode
+   * must be set in the constructor options.  So there is effectively
+   * no allowed way that a TS program can set the encoding after
+   * construction, as doing so will destroy any hope of type safety.
+   * TypeScript does not provide many options for changing the type of
+   * an object at run-time, which is what changing the encoding does.
+   */
+  readonly encoding: Minipass.Encoding
+  // setEncoding(encoding: Encoding): void
+
+  // Options required if not reading buffers
+  constructor(
+    ...args: RType extends Buffer
+      ? [] | [Minipass.Options<RType>]
+      : [Minipass.Options<RType>]
+  )
+
+  write(chunk: WType, cb?: () => void): boolean
+  write(chunk: WType, encoding?: Minipass.Encoding, cb?: () => void): boolean
+  read(size?: number): RType
+  end(cb?: () => void): this
+  end(chunk: any, cb?: () => void): this
+  end(chunk: any, encoding?: Minipass.Encoding, cb?: () => void): this
+  pause(): void
+  resume(): void
+  promise(): Promise<void>
+  collect(): Promise<RType[]>
+
+  concat(): RType extends Minipass.BufferOrString ? Promise<RType> : never
+  destroy(er?: any): void
+  pipe<W extends Minipass.Writable>(dest: W, opts?: Minipass.PipeOptions): W
+  unpipe<W extends Minipass.Writable>(dest: W): void
+
+  /**
+   * alias for on()
+   */
+  addEventHandler(event: string, listener: (...args: any[]) => any): this
+
+  on(event: string, listener: (...args: any[]) => any): this
+  on(event: 'data', listener: (chunk: RType) => any): this
+  on(event: 'error', listener: (error: any) => any): this
+  on(
+    event:
+      | 'readable'
+      | 'drain'
+      | 'resume'
+      | 'end'
+      | 'prefinish'
+      | 'finish'
+      | 'close',
+    listener: () => any
+  ): this
+
+  [Symbol.iterator](): Generator<RType, void, void>
+  [Symbol.asyncIterator](): AsyncGenerator<RType, void, void>
+}
diff --git a/server/node_modules/tar/node_modules/minipass/index.js b/server/node_modules/tar/node_modules/minipass/index.js
new file mode 100644
index 0000000..ed07c17
--- /dev/null
+++ b/server/node_modules/tar/node_modules/minipass/index.js
@@ -0,0 +1,702 @@
+'use strict'
+const proc =
+  typeof process === 'object' && process
+    ? process
+    : {
+        stdout: null,
+        stderr: null,
+      }
+const EE = require('events')
+const Stream = require('stream')
+const stringdecoder = require('string_decoder')
+const SD = stringdecoder.StringDecoder
+
+const EOF = Symbol('EOF')
+const MAYBE_EMIT_END = Symbol('maybeEmitEnd')
+const EMITTED_END = Symbol('emittedEnd')
+const EMITTING_END = Symbol('emittingEnd')
+const EMITTED_ERROR = Symbol('emittedError')
+const CLOSED = Symbol('closed')
+const READ = Symbol('read')
+const FLUSH = Symbol('flush')
+const FLUSHCHUNK = Symbol('flushChunk')
+const ENCODING = Symbol('encoding')
+const DECODER = Symbol('decoder')
+const FLOWING = Symbol('flowing')
+const PAUSED = Symbol('paused')
+const RESUME = Symbol('resume')
+const BUFFER = Symbol('buffer')
+const PIPES = Symbol('pipes')
+const BUFFERLENGTH = Symbol('bufferLength')
+const BUFFERPUSH = Symbol('bufferPush')
+const BUFFERSHIFT = Symbol('bufferShift')
+const OBJECTMODE = Symbol('objectMode')
+// internal event when stream is destroyed
+const DESTROYED = Symbol('destroyed')
+// internal event when stream has an error
+const ERROR = Symbol('error')
+const EMITDATA = Symbol('emitData')
+const EMITEND = Symbol('emitEnd')
+const EMITEND2 = Symbol('emitEnd2')
+const ASYNC = Symbol('async')
+const ABORT = Symbol('abort')
+const ABORTED = Symbol('aborted')
+const SIGNAL = Symbol('signal')
+
+const defer = fn => Promise.resolve().then(fn)
+
+// TODO remove when Node v8 support drops
+const doIter = global._MP_NO_ITERATOR_SYMBOLS_ !== '1'
+const ASYNCITERATOR =
+  (doIter && Symbol.asyncIterator) || Symbol('asyncIterator not implemented')
+const ITERATOR =
+  (doIter && Symbol.iterator) || Symbol('iterator not implemented')
+
+// events that mean 'the stream is over'
+// these are treated specially, and re-emitted
+// if they are listened for after emitting.
+const isEndish = ev => ev === 'end' || ev === 'finish' || ev === 'prefinish'
+
+const isArrayBuffer = b =>
+  b instanceof ArrayBuffer ||
+  (typeof b === 'object' &&
+    b.constructor &&
+    b.constructor.name === 'ArrayBuffer' &&
+    b.byteLength >= 0)
+
+const isArrayBufferView = b => !Buffer.isBuffer(b) && ArrayBuffer.isView(b)
+
+class Pipe {
+  constructor(src, dest, opts) {
+    this.src = src
+    this.dest = dest
+    this.opts = opts
+    this.ondrain = () => src[RESUME]()
+    dest.on('drain', this.ondrain)
+  }
+  unpipe() {
+    this.dest.removeListener('drain', this.ondrain)
+  }
+  // istanbul ignore next - only here for the prototype
+  proxyErrors() {}
+  end() {
+    this.unpipe()
+    if (this.opts.end) this.dest.end()
+  }
+}
+
+class PipeProxyErrors extends Pipe {
+  unpipe() {
+    this.src.removeListener('error', this.proxyErrors)
+    super.unpipe()
+  }
+  constructor(src, dest, opts) {
+    super(src, dest, opts)
+    this.proxyErrors = er => dest.emit('error', er)
+    src.on('error', this.proxyErrors)
+  }
+}
+
+class Minipass extends Stream {
+  constructor(options) {
+    super()
+    this[FLOWING] = false
+    // whether we're explicitly paused
+    this[PAUSED] = false
+    this[PIPES] = []
+    this[BUFFER] = []
+    this[OBJECTMODE] = (options && options.objectMode) || false
+    if (this[OBJECTMODE]) this[ENCODING] = null
+    else this[ENCODING] = (options && options.encoding) || null
+    if (this[ENCODING] === 'buffer') this[ENCODING] = null
+    this[ASYNC] = (options && !!options.async) || false
+    this[DECODER] = this[ENCODING] ? new SD(this[ENCODING]) : null
+    this[EOF] = false
+    this[EMITTED_END] = false
+    this[EMITTING_END] = false
+    this[CLOSED] = false
+    this[EMITTED_ERROR] = null
+    this.writable = true
+    this.readable = true
+    this[BUFFERLENGTH] = 0
+    this[DESTROYED] = false
+    if (options && options.debugExposeBuffer === true) {
+      Object.defineProperty(this, 'buffer', { get: () => this[BUFFER] })
+    }
+    if (options && options.debugExposePipes === true) {
+      Object.defineProperty(this, 'pipes', { get: () => this[PIPES] })
+    }
+    this[SIGNAL] = options && options.signal
+    this[ABORTED] = false
+    if (this[SIGNAL]) {
+      this[SIGNAL].addEventListener('abort', () => this[ABORT]())
+      if (this[SIGNAL].aborted) {
+        this[ABORT]()
+      }
+    }
+  }
+
+  get bufferLength() {
+    return this[BUFFERLENGTH]
+  }
+
+  get encoding() {
+    return this[ENCODING]
+  }
+  set encoding(enc) {
+    if (this[OBJECTMODE]) throw new Error('cannot set encoding in objectMode')
+
+    if (
+      this[ENCODING] &&
+      enc !== this[ENCODING] &&
+      ((this[DECODER] && this[DECODER].lastNeed) || this[BUFFERLENGTH])
+    )
+      throw new Error('cannot change encoding')
+
+    if (this[ENCODING] !== enc) {
+      this[DECODER] = enc ? new SD(enc) : null
+      if (this[BUFFER].length)
+        this[BUFFER] = this[BUFFER].map(chunk => this[DECODER].write(chunk))
+    }
+
+    this[ENCODING] = enc
+  }
+
+  setEncoding(enc) {
+    this.encoding = enc
+  }
+
+  get objectMode() {
+    return this[OBJECTMODE]
+  }
+  set objectMode(om) {
+    this[OBJECTMODE] = this[OBJECTMODE] || !!om
+  }
+
+  get ['async']() {
+    return this[ASYNC]
+  }
+  set ['async'](a) {
+    this[ASYNC] = this[ASYNC] || !!a
+  }
+
+  // drop everything and get out of the flow completely
+  [ABORT]() {
+    this[ABORTED] = true
+    this.emit('abort', this[SIGNAL].reason)
+    this.destroy(this[SIGNAL].reason)
+  }
+
+  get aborted() {
+    return this[ABORTED]
+  }
+  set aborted(_) {}
+
+  write(chunk, encoding, cb) {
+    if (this[ABORTED]) return false
+    if (this[EOF]) throw new Error('write after end')
+
+    if (this[DESTROYED]) {
+      this.emit(
+        'error',
+        Object.assign(
+          new Error('Cannot call write after a stream was destroyed'),
+          { code: 'ERR_STREAM_DESTROYED' }
+        )
+      )
+      return true
+    }
+
+    if (typeof encoding === 'function') (cb = encoding), (encoding = 'utf8')
+
+    if (!encoding) encoding = 'utf8'
+
+    const fn = this[ASYNC] ? defer : f => f()
+
+    // convert array buffers and typed array views into buffers
+    // at some point in the future, we may want to do the opposite!
+    // leave strings and buffers as-is
+    // anything else switches us into object mode
+    if (!this[OBJECTMODE] && !Buffer.isBuffer(chunk)) {
+      if (isArrayBufferView(chunk))
+        chunk = Buffer.from(chunk.buffer, chunk.byteOffset, chunk.byteLength)
+      else if (isArrayBuffer(chunk)) chunk = Buffer.from(chunk)
+      else if (typeof chunk !== 'string')
+        // use the setter so we throw if we have encoding set
+        this.objectMode = true
+    }
+
+    // handle object mode up front, since it's simpler
+    // this yields better performance, fewer checks later.
+    if (this[OBJECTMODE]) {
+      /* istanbul ignore if - maybe impossible? */
+      if (this.flowing && this[BUFFERLENGTH] !== 0) this[FLUSH](true)
+
+      if (this.flowing) this.emit('data', chunk)
+      else this[BUFFERPUSH](chunk)
+
+      if (this[BUFFERLENGTH] !== 0) this.emit('readable')
+
+      if (cb) fn(cb)
+
+      return this.flowing
+    }
+
+    // at this point the chunk is a buffer or string
+    // don't buffer it up or send it to the decoder
+    if (!chunk.length) {
+      if (this[BUFFERLENGTH] !== 0) this.emit('readable')
+      if (cb) fn(cb)
+      return this.flowing
+    }
+
+    // fast-path writing strings of same encoding to a stream with
+    // an empty buffer, skipping the buffer/decoder dance
+    if (
+      typeof chunk === 'string' &&
+      // unless it is a string already ready for us to use
+      !(encoding === this[ENCODING] && !this[DECODER].lastNeed)
+    ) {
+      chunk = Buffer.from(chunk, encoding)
+    }
+
+    if (Buffer.isBuffer(chunk) && this[ENCODING])
+      chunk = this[DECODER].write(chunk)
+
+    // Note: flushing CAN potentially switch us into not-flowing mode
+    if (this.flowing && this[BUFFERLENGTH] !== 0) this[FLUSH](true)
+
+    if (this.flowing) this.emit('data', chunk)
+    else this[BUFFERPUSH](chunk)
+
+    if (this[BUFFERLENGTH] !== 0) this.emit('readable')
+
+    if (cb) fn(cb)
+
+    return this.flowing
+  }
+
+  read(n) {
+    if (this[DESTROYED]) return null
+
+    if (this[BUFFERLENGTH] === 0 || n === 0 || n > this[BUFFERLENGTH]) {
+      this[MAYBE_EMIT_END]()
+      return null
+    }
+
+    if (this[OBJECTMODE]) n = null
+
+    if (this[BUFFER].length > 1 && !this[OBJECTMODE]) {
+      if (this.encoding) this[BUFFER] = [this[BUFFER].join('')]
+      else this[BUFFER] = [Buffer.concat(this[BUFFER], this[BUFFERLENGTH])]
+    }
+
+    const ret = this[READ](n || null, this[BUFFER][0])
+    this[MAYBE_EMIT_END]()
+    return ret
+  }
+
+  [READ](n, chunk) {
+    if (n === chunk.length || n === null) this[BUFFERSHIFT]()
+    else {
+      this[BUFFER][0] = chunk.slice(n)
+      chunk = chunk.slice(0, n)
+      this[BUFFERLENGTH] -= n
+    }
+
+    this.emit('data', chunk)
+
+    if (!this[BUFFER].length && !this[EOF]) this.emit('drain')
+
+    return chunk
+  }
+
+  end(chunk, encoding, cb) {
+    if (typeof chunk === 'function') (cb = chunk), (chunk = null)
+    if (typeof encoding === 'function') (cb = encoding), (encoding = 'utf8')
+    if (chunk) this.write(chunk, encoding)
+    if (cb) this.once('end', cb)
+    this[EOF] = true
+    this.writable = false
+
+    // if we haven't written anything, then go ahead and emit,
+    // even if we're not reading.
+    // we'll re-emit if a new 'end' listener is added anyway.
+    // This makes MP more suitable to write-only use cases.
+    if (this.flowing || !this[PAUSED]) this[MAYBE_EMIT_END]()
+    return this
+  }
+
+  // don't let the internal resume be overwritten
+  [RESUME]() {
+    if (this[DESTROYED]) return
+
+    this[PAUSED] = false
+    this[FLOWING] = true
+    this.emit('resume')
+    if (this[BUFFER].length) this[FLUSH]()
+    else if (this[EOF]) this[MAYBE_EMIT_END]()
+    else this.emit('drain')
+  }
+
+  resume() {
+    return this[RESUME]()
+  }
+
+  pause() {
+    this[FLOWING] = false
+    this[PAUSED] = true
+  }
+
+  get destroyed() {
+    return this[DESTROYED]
+  }
+
+  get flowing() {
+    return this[FLOWING]
+  }
+
+  get paused() {
+    return this[PAUSED]
+  }
+
+  [BUFFERPUSH](chunk) {
+    if (this[OBJECTMODE]) this[BUFFERLENGTH] += 1
+    else this[BUFFERLENGTH] += chunk.length
+    this[BUFFER].push(chunk)
+  }
+
+  [BUFFERSHIFT]() {
+    if (this[OBJECTMODE]) this[BUFFERLENGTH] -= 1
+    else this[BUFFERLENGTH] -= this[BUFFER][0].length
+    return this[BUFFER].shift()
+  }
+
+  [FLUSH](noDrain) {
+    do {} while (this[FLUSHCHUNK](this[BUFFERSHIFT]()) && this[BUFFER].length)
+
+    if (!noDrain && !this[BUFFER].length && !this[EOF]) this.emit('drain')
+  }
+
+  [FLUSHCHUNK](chunk) {
+    this.emit('data', chunk)
+    return this.flowing
+  }
+
+  pipe(dest, opts) {
+    if (this[DESTROYED]) return
+
+    const ended = this[EMITTED_END]
+    opts = opts || {}
+    if (dest === proc.stdout || dest === proc.stderr) opts.end = false
+    else opts.end = opts.end !== false
+    opts.proxyErrors = !!opts.proxyErrors
+
+    // piping an ended stream ends immediately
+    if (ended) {
+      if (opts.end) dest.end()
+    } else {
+      this[PIPES].push(
+        !opts.proxyErrors
+          ? new Pipe(this, dest, opts)
+          : new PipeProxyErrors(this, dest, opts)
+      )
+      if (this[ASYNC]) defer(() => this[RESUME]())
+      else this[RESUME]()
+    }
+
+    return dest
+  }
+
+  unpipe(dest) {
+    const p = this[PIPES].find(p => p.dest === dest)
+    if (p) {
+      this[PIPES].splice(this[PIPES].indexOf(p), 1)
+      p.unpipe()
+    }
+  }
+
+  addListener(ev, fn) {
+    return this.on(ev, fn)
+  }
+
+  on(ev, fn) {
+    const ret = super.on(ev, fn)
+    if (ev === 'data' && !this[PIPES].length && !this.flowing) this[RESUME]()
+    else if (ev === 'readable' && this[BUFFERLENGTH] !== 0)
+      super.emit('readable')
+    else if (isEndish(ev) && this[EMITTED_END]) {
+      super.emit(ev)
+      this.removeAllListeners(ev)
+    } else if (ev === 'error' && this[EMITTED_ERROR]) {
+      if (this[ASYNC]) defer(() => fn.call(this, this[EMITTED_ERROR]))
+      else fn.call(this, this[EMITTED_ERROR])
+    }
+    return ret
+  }
+
+  get emittedEnd() {
+    return this[EMITTED_END]
+  }
+
+  [MAYBE_EMIT_END]() {
+    if (
+      !this[EMITTING_END] &&
+      !this[EMITTED_END] &&
+      !this[DESTROYED] &&
+      this[BUFFER].length === 0 &&
+      this[EOF]
+    ) {
+      this[EMITTING_END] = true
+      this.emit('end')
+      this.emit('prefinish')
+      this.emit('finish')
+      if (this[CLOSED]) this.emit('close')
+      this[EMITTING_END] = false
+    }
+  }
+
+  emit(ev, data, ...extra) {
+    // error and close are only events allowed after calling destroy()
+    if (ev !== 'error' && ev !== 'close' && ev !== DESTROYED && this[DESTROYED])
+      return
+    else if (ev === 'data') {
+      return !this[OBJECTMODE] && !data
+        ? false
+        : this[ASYNC]
+        ? defer(() => this[EMITDATA](data))
+        : this[EMITDATA](data)
+    } else if (ev === 'end') {
+      return this[EMITEND]()
+    } else if (ev === 'close') {
+      this[CLOSED] = true
+      // don't emit close before 'end' and 'finish'
+      if (!this[EMITTED_END] && !this[DESTROYED]) return
+      const ret = super.emit('close')
+      this.removeAllListeners('close')
+      return ret
+    } else if (ev === 'error') {
+      this[EMITTED_ERROR] = data
+      super.emit(ERROR, data)
+      const ret =
+        !this[SIGNAL] || this.listeners('error').length
+          ? super.emit('error', data)
+          : false
+      this[MAYBE_EMIT_END]()
+      return ret
+    } else if (ev === 'resume') {
+      const ret = super.emit('resume')
+      this[MAYBE_EMIT_END]()
+      return ret
+    } else if (ev === 'finish' || ev === 'prefinish') {
+      const ret = super.emit(ev)
+      this.removeAllListeners(ev)
+      return ret
+    }
+
+    // Some other unknown event
+    const ret = super.emit(ev, data, ...extra)
+    this[MAYBE_EMIT_END]()
+    return ret
+  }
+
+  [EMITDATA](data) {
+    for (const p of this[PIPES]) {
+      if (p.dest.write(data) === false) this.pause()
+    }
+    const ret = super.emit('data', data)
+    this[MAYBE_EMIT_END]()
+    return ret
+  }
+
+  [EMITEND]() {
+    if (this[EMITTED_END]) return
+
+    this[EMITTED_END] = true
+    this.readable = false
+    if (this[ASYNC]) defer(() => this[EMITEND2]())
+    else this[EMITEND2]()
+  }
+
+  [EMITEND2]() {
+    if (this[DECODER]) {
+      const data = this[DECODER].end()
+      if (data) {
+        for (const p of this[PIPES]) {
+          p.dest.write(data)
+        }
+        super.emit('data', data)
+      }
+    }
+
+    for (const p of this[PIPES]) {
+      p.end()
+    }
+    const ret = super.emit('end')
+    this.removeAllListeners('end')
+    return ret
+  }
+
+  // const all = await stream.collect()
+  collect() {
+    const buf = []
+    if (!this[OBJECTMODE]) buf.dataLength = 0
+    // set the promise first, in case an error is raised
+    // by triggering the flow here.
+    const p = this.promise()
+    this.on('data', c => {
+      buf.push(c)
+      if (!this[OBJECTMODE]) buf.dataLength += c.length
+    })
+    return p.then(() => buf)
+  }
+
+  // const data = await stream.concat()
+  concat() {
+    return this[OBJECTMODE]
+      ? Promise.reject(new Error('cannot concat in objectMode'))
+      : this.collect().then(buf =>
+          this[OBJECTMODE]
+            ? Promise.reject(new Error('cannot concat in objectMode'))
+            : this[ENCODING]
+            ? buf.join('')
+            : Buffer.concat(buf, buf.dataLength)
+        )
+  }
+
+  // stream.promise().then(() => done, er => emitted error)
+  promise() {
+    return new Promise((resolve, reject) => {
+      this.on(DESTROYED, () => reject(new Error('stream destroyed')))
+      this.on('error', er => reject(er))
+      this.on('end', () => resolve())
+    })
+  }
+
+  // for await (let chunk of stream)
+  [ASYNCITERATOR]() {
+    let stopped = false
+    const stop = () => {
+      this.pause()
+      stopped = true
+      return Promise.resolve({ done: true })
+    }
+    const next = () => {
+      if (stopped) return stop()
+      const res = this.read()
+      if (res !== null) return Promise.resolve({ done: false, value: res })
+
+      if (this[EOF]) return stop()
+
+      let resolve = null
+      let reject = null
+      const onerr = er => {
+        this.removeListener('data', ondata)
+        this.removeListener('end', onend)
+        this.removeListener(DESTROYED, ondestroy)
+        stop()
+        reject(er)
+      }
+      const ondata = value => {
+        this.removeListener('error', onerr)
+        this.removeListener('end', onend)
+        this.removeListener(DESTROYED, ondestroy)
+        this.pause()
+        resolve({ value: value, done: !!this[EOF] })
+      }
+      const onend = () => {
+        this.removeListener('error', onerr)
+        this.removeListener('data', ondata)
+        this.removeListener(DESTROYED, ondestroy)
+        stop()
+        resolve({ done: true })
+      }
+      const ondestroy = () => onerr(new Error('stream destroyed'))
+      return new Promise((res, rej) => {
+        reject = rej
+        resolve = res
+        this.once(DESTROYED, ondestroy)
+        this.once('error', onerr)
+        this.once('end', onend)
+        this.once('data', ondata)
+      })
+    }
+
+    return {
+      next,
+      throw: stop,
+      return: stop,
+      [ASYNCITERATOR]() {
+        return this
+      },
+    }
+  }
+
+  // for (let chunk of stream)
+  [ITERATOR]() {
+    let stopped = false
+    const stop = () => {
+      this.pause()
+      this.removeListener(ERROR, stop)
+      this.removeListener(DESTROYED, stop)
+      this.removeListener('end', stop)
+      stopped = true
+      return { done: true }
+    }
+
+    const next = () => {
+      if (stopped) return stop()
+      const value = this.read()
+      return value === null ? stop() : { value }
+    }
+    this.once('end', stop)
+    this.once(ERROR, stop)
+    this.once(DESTROYED, stop)
+
+    return {
+      next,
+      throw: stop,
+      return: stop,
+      [ITERATOR]() {
+        return this
+      },
+    }
+  }
+
+  destroy(er) {
+    if (this[DESTROYED]) {
+      if (er) this.emit('error', er)
+      else this.emit(DESTROYED)
+      return this
+    }
+
+    this[DESTROYED] = true
+
+    // throw away all buffered data, it's never coming out
+    this[BUFFER].length = 0
+    this[BUFFERLENGTH] = 0
+
+    if (typeof this.close === 'function' && !this[CLOSED]) this.close()
+
+    if (er) this.emit('error', er)
+    // if no error to emit, still reject pending promises
+    else this.emit(DESTROYED)
+
+    return this
+  }
+
+  static isStream(s) {
+    return (
+      !!s &&
+      (s instanceof Minipass ||
+        s instanceof Stream ||
+        (s instanceof EE &&
+          // readable
+          (typeof s.pipe === 'function' ||
+            // writable
+            (typeof s.write === 'function' && typeof s.end === 'function'))))
+    )
+  }
+}
+
+exports.Minipass = Minipass
diff --git a/server/node_modules/tar/node_modules/minipass/index.mjs b/server/node_modules/tar/node_modules/minipass/index.mjs
new file mode 100644
index 0000000..6ef6cd8
--- /dev/null
+++ b/server/node_modules/tar/node_modules/minipass/index.mjs
@@ -0,0 +1,702 @@
+'use strict'
+const proc =
+  typeof process === 'object' && process
+    ? process
+    : {
+        stdout: null,
+        stderr: null,
+      }
+import EE from 'events'
+import Stream from 'stream'
+import stringdecoder from 'string_decoder'
+const SD = stringdecoder.StringDecoder
+
+const EOF = Symbol('EOF')
+const MAYBE_EMIT_END = Symbol('maybeEmitEnd')
+const EMITTED_END = Symbol('emittedEnd')
+const EMITTING_END = Symbol('emittingEnd')
+const EMITTED_ERROR = Symbol('emittedError')
+const CLOSED = Symbol('closed')
+const READ = Symbol('read')
+const FLUSH = Symbol('flush')
+const FLUSHCHUNK = Symbol('flushChunk')
+const ENCODING = Symbol('encoding')
+const DECODER = Symbol('decoder')
+const FLOWING = Symbol('flowing')
+const PAUSED = Symbol('paused')
+const RESUME = Symbol('resume')
+const BUFFER = Symbol('buffer')
+const PIPES = Symbol('pipes')
+const BUFFERLENGTH = Symbol('bufferLength')
+const BUFFERPUSH = Symbol('bufferPush')
+const BUFFERSHIFT = Symbol('bufferShift')
+const OBJECTMODE = Symbol('objectMode')
+// internal event when stream is destroyed
+const DESTROYED = Symbol('destroyed')
+// internal event when stream has an error
+const ERROR = Symbol('error')
+const EMITDATA = Symbol('emitData')
+const EMITEND = Symbol('emitEnd')
+const EMITEND2 = Symbol('emitEnd2')
+const ASYNC = Symbol('async')
+const ABORT = Symbol('abort')
+const ABORTED = Symbol('aborted')
+const SIGNAL = Symbol('signal')
+
+const defer = fn => Promise.resolve().then(fn)
+
+// TODO remove when Node v8 support drops
+const doIter = global._MP_NO_ITERATOR_SYMBOLS_ !== '1'
+const ASYNCITERATOR =
+  (doIter && Symbol.asyncIterator) || Symbol('asyncIterator not implemented')
+const ITERATOR =
+  (doIter && Symbol.iterator) || Symbol('iterator not implemented')
+
+// events that mean 'the stream is over'
+// these are treated specially, and re-emitted
+// if they are listened for after emitting.
+const isEndish = ev => ev === 'end' || ev === 'finish' || ev === 'prefinish'
+
+const isArrayBuffer = b =>
+  b instanceof ArrayBuffer ||
+  (typeof b === 'object' &&
+    b.constructor &&
+    b.constructor.name === 'ArrayBuffer' &&
+    b.byteLength >= 0)
+
+const isArrayBufferView = b => !Buffer.isBuffer(b) && ArrayBuffer.isView(b)
+
+class Pipe {
+  constructor(src, dest, opts) {
+    this.src = src
+    this.dest = dest
+    this.opts = opts
+    this.ondrain = () => src[RESUME]()
+    dest.on('drain', this.ondrain)
+  }
+  unpipe() {
+    this.dest.removeListener('drain', this.ondrain)
+  }
+  // istanbul ignore next - only here for the prototype
+  proxyErrors() {}
+  end() {
+    this.unpipe()
+    if (this.opts.end) this.dest.end()
+  }
+}
+
+class PipeProxyErrors extends Pipe {
+  unpipe() {
+    this.src.removeListener('error', this.proxyErrors)
+    super.unpipe()
+  }
+  constructor(src, dest, opts) {
+    super(src, dest, opts)
+    this.proxyErrors = er => dest.emit('error', er)
+    src.on('error', this.proxyErrors)
+  }
+}
+
+export class Minipass extends Stream {
+  constructor(options) {
+    super()
+    this[FLOWING] = false
+    // whether we're explicitly paused
+    this[PAUSED] = false
+    this[PIPES] = []
+    this[BUFFER] = []
+    this[OBJECTMODE] = (options && options.objectMode) || false
+    if (this[OBJECTMODE]) this[ENCODING] = null
+    else this[ENCODING] = (options && options.encoding) || null
+    if (this[ENCODING] === 'buffer') this[ENCODING] = null
+    this[ASYNC] = (options && !!options.async) || false
+    this[DECODER] = this[ENCODING] ? new SD(this[ENCODING]) : null
+    this[EOF] = false
+    this[EMITTED_END] = false
+    this[EMITTING_END] = false
+    this[CLOSED] = false
+    this[EMITTED_ERROR] = null
+    this.writable = true
+    this.readable = true
+    this[BUFFERLENGTH] = 0
+    this[DESTROYED] = false
+    if (options && options.debugExposeBuffer === true) {
+      Object.defineProperty(this, 'buffer', { get: () => this[BUFFER] })
+    }
+    if (options && options.debugExposePipes === true) {
+      Object.defineProperty(this, 'pipes', { get: () => this[PIPES] })
+    }
+    this[SIGNAL] = options && options.signal
+    this[ABORTED] = false
+    if (this[SIGNAL]) {
+      this[SIGNAL].addEventListener('abort', () => this[ABORT]())
+      if (this[SIGNAL].aborted) {
+        this[ABORT]()
+      }
+    }
+  }
+
+  get bufferLength() {
+    return this[BUFFERLENGTH]
+  }
+
+  get encoding() {
+    return this[ENCODING]
+  }
+  set encoding(enc) {
+    if (this[OBJECTMODE]) throw new Error('cannot set encoding in objectMode')
+
+    if (
+      this[ENCODING] &&
+      enc !== this[ENCODING] &&
+      ((this[DECODER] && this[DECODER].lastNeed) || this[BUFFERLENGTH])
+    )
+      throw new Error('cannot change encoding')
+
+    if (this[ENCODING] !== enc) {
+      this[DECODER] = enc ? new SD(enc) : null
+      if (this[BUFFER].length)
+        this[BUFFER] = this[BUFFER].map(chunk => this[DECODER].write(chunk))
+    }
+
+    this[ENCODING] = enc
+  }
+
+  setEncoding(enc) {
+    this.encoding = enc
+  }
+
+  get objectMode() {
+    return this[OBJECTMODE]
+  }
+  set objectMode(om) {
+    this[OBJECTMODE] = this[OBJECTMODE] || !!om
+  }
+
+  get ['async']() {
+    return this[ASYNC]
+  }
+  set ['async'](a) {
+    this[ASYNC] = this[ASYNC] || !!a
+  }
+
+  // drop everything and get out of the flow completely
+  [ABORT]() {
+    this[ABORTED] = true
+    this.emit('abort', this[SIGNAL].reason)
+    this.destroy(this[SIGNAL].reason)
+  }
+
+  get aborted() {
+    return this[ABORTED]
+  }
+  set aborted(_) {}
+
+  write(chunk, encoding, cb) {
+    if (this[ABORTED]) return false
+    if (this[EOF]) throw new Error('write after end')
+
+    if (this[DESTROYED]) {
+      this.emit(
+        'error',
+        Object.assign(
+          new Error('Cannot call write after a stream was destroyed'),
+          { code: 'ERR_STREAM_DESTROYED' }
+        )
+      )
+      return true
+    }
+
+    if (typeof encoding === 'function') (cb = encoding), (encoding = 'utf8')
+
+    if (!encoding) encoding = 'utf8'
+
+    const fn = this[ASYNC] ? defer : f => f()
+
+    // convert array buffers and typed array views into buffers
+    // at some point in the future, we may want to do the opposite!
+    // leave strings and buffers as-is
+    // anything else switches us into object mode
+    if (!this[OBJECTMODE] && !Buffer.isBuffer(chunk)) {
+      if (isArrayBufferView(chunk))
+        chunk = Buffer.from(chunk.buffer, chunk.byteOffset, chunk.byteLength)
+      else if (isArrayBuffer(chunk)) chunk = Buffer.from(chunk)
+      else if (typeof chunk !== 'string')
+        // use the setter so we throw if we have encoding set
+        this.objectMode = true
+    }
+
+    // handle object mode up front, since it's simpler
+    // this yields better performance, fewer checks later.
+    if (this[OBJECTMODE]) {
+      /* istanbul ignore if - maybe impossible? */
+      if (this.flowing && this[BUFFERLENGTH] !== 0) this[FLUSH](true)
+
+      if (this.flowing) this.emit('data', chunk)
+      else this[BUFFERPUSH](chunk)
+
+      if (this[BUFFERLENGTH] !== 0) this.emit('readable')
+
+      if (cb) fn(cb)
+
+      return this.flowing
+    }
+
+    // at this point the chunk is a buffer or string
+    // don't buffer it up or send it to the decoder
+    if (!chunk.length) {
+      if (this[BUFFERLENGTH] !== 0) this.emit('readable')
+      if (cb) fn(cb)
+      return this.flowing
+    }
+
+    // fast-path writing strings of same encoding to a stream with
+    // an empty buffer, skipping the buffer/decoder dance
+    if (
+      typeof chunk === 'string' &&
+      // unless it is a string already ready for us to use
+      !(encoding === this[ENCODING] && !this[DECODER].lastNeed)
+    ) {
+      chunk = Buffer.from(chunk, encoding)
+    }
+
+    if (Buffer.isBuffer(chunk) && this[ENCODING])
+      chunk = this[DECODER].write(chunk)
+
+    // Note: flushing CAN potentially switch us into not-flowing mode
+    if (this.flowing && this[BUFFERLENGTH] !== 0) this[FLUSH](true)
+
+    if (this.flowing) this.emit('data', chunk)
+    else this[BUFFERPUSH](chunk)
+
+    if (this[BUFFERLENGTH] !== 0) this.emit('readable')
+
+    if (cb) fn(cb)
+
+    return this.flowing
+  }
+
+  read(n) {
+    if (this[DESTROYED]) return null
+
+    if (this[BUFFERLENGTH] === 0 || n === 0 || n > this[BUFFERLENGTH]) {
+      this[MAYBE_EMIT_END]()
+      return null
+    }
+
+    if (this[OBJECTMODE]) n = null
+
+    if (this[BUFFER].length > 1 && !this[OBJECTMODE]) {
+      if (this.encoding) this[BUFFER] = [this[BUFFER].join('')]
+      else this[BUFFER] = [Buffer.concat(this[BUFFER], this[BUFFERLENGTH])]
+    }
+
+    const ret = this[READ](n || null, this[BUFFER][0])
+    this[MAYBE_EMIT_END]()
+    return ret
+  }
+
+  [READ](n, chunk) {
+    if (n === chunk.length || n === null) this[BUFFERSHIFT]()
+    else {
+      this[BUFFER][0] = chunk.slice(n)
+      chunk = chunk.slice(0, n)
+      this[BUFFERLENGTH] -= n
+    }
+
+    this.emit('data', chunk)
+
+    if (!this[BUFFER].length && !this[EOF]) this.emit('drain')
+
+    return chunk
+  }
+
+  end(chunk, encoding, cb) {
+    if (typeof chunk === 'function') (cb = chunk), (chunk = null)
+    if (typeof encoding === 'function') (cb = encoding), (encoding = 'utf8')
+    if (chunk) this.write(chunk, encoding)
+    if (cb) this.once('end', cb)
+    this[EOF] = true
+    this.writable = false
+
+    // if we haven't written anything, then go ahead and emit,
+    // even if we're not reading.
+    // we'll re-emit if a new 'end' listener is added anyway.
+    // This makes MP more suitable to write-only use cases.
+    if (this.flowing || !this[PAUSED]) this[MAYBE_EMIT_END]()
+    return this
+  }
+
+  // don't let the internal resume be overwritten
+  [RESUME]() {
+    if (this[DESTROYED]) return
+
+    this[PAUSED] = false
+    this[FLOWING] = true
+    this.emit('resume')
+    if (this[BUFFER].length) this[FLUSH]()
+    else if (this[EOF]) this[MAYBE_EMIT_END]()
+    else this.emit('drain')
+  }
+
+  resume() {
+    return this[RESUME]()
+  }
+
+  pause() {
+    this[FLOWING] = false
+    this[PAUSED] = true
+  }
+
+  get destroyed() {
+    return this[DESTROYED]
+  }
+
+  get flowing() {
+    return this[FLOWING]
+  }
+
+  get paused() {
+    return this[PAUSED]
+  }
+
+  [BUFFERPUSH](chunk) {
+    if (this[OBJECTMODE]) this[BUFFERLENGTH] += 1
+    else this[BUFFERLENGTH] += chunk.length
+    this[BUFFER].push(chunk)
+  }
+
+  [BUFFERSHIFT]() {
+    if (this[OBJECTMODE]) this[BUFFERLENGTH] -= 1
+    else this[BUFFERLENGTH] -= this[BUFFER][0].length
+    return this[BUFFER].shift()
+  }
+
+  [FLUSH](noDrain) {
+    do {} while (this[FLUSHCHUNK](this[BUFFERSHIFT]()) && this[BUFFER].length)
+
+    if (!noDrain && !this[BUFFER].length && !this[EOF]) this.emit('drain')
+  }
+
+  [FLUSHCHUNK](chunk) {
+    this.emit('data', chunk)
+    return this.flowing
+  }
+
+  pipe(dest, opts) {
+    if (this[DESTROYED]) return
+
+    const ended = this[EMITTED_END]
+    opts = opts || {}
+    if (dest === proc.stdout || dest === proc.stderr) opts.end = false
+    else opts.end = opts.end !== false
+    opts.proxyErrors = !!opts.proxyErrors
+
+    // piping an ended stream ends immediately
+    if (ended) {
+      if (opts.end) dest.end()
+    } else {
+      this[PIPES].push(
+        !opts.proxyErrors
+          ? new Pipe(this, dest, opts)
+          : new PipeProxyErrors(this, dest, opts)
+      )
+      if (this[ASYNC]) defer(() => this[RESUME]())
+      else this[RESUME]()
+    }
+
+    return dest
+  }
+
+  unpipe(dest) {
+    const p = this[PIPES].find(p => p.dest === dest)
+    if (p) {
+      this[PIPES].splice(this[PIPES].indexOf(p), 1)
+      p.unpipe()
+    }
+  }
+
+  addListener(ev, fn) {
+    return this.on(ev, fn)
+  }
+
+  on(ev, fn) {
+    const ret = super.on(ev, fn)
+    if (ev === 'data' && !this[PIPES].length && !this.flowing) this[RESUME]()
+    else if (ev === 'readable' && this[BUFFERLENGTH] !== 0)
+      super.emit('readable')
+    else if (isEndish(ev) && this[EMITTED_END]) {
+      super.emit(ev)
+      this.removeAllListeners(ev)
+    } else if (ev === 'error' && this[EMITTED_ERROR]) {
+      if (this[ASYNC]) defer(() => fn.call(this, this[EMITTED_ERROR]))
+      else fn.call(this, this[EMITTED_ERROR])
+    }
+    return ret
+  }
+
+  get emittedEnd() {
+    return this[EMITTED_END]
+  }
+
+  [MAYBE_EMIT_END]() {
+    if (
+      !this[EMITTING_END] &&
+      !this[EMITTED_END] &&
+      !this[DESTROYED] &&
+      this[BUFFER].length === 0 &&
+      this[EOF]
+    ) {
+      this[EMITTING_END] = true
+      this.emit('end')
+      this.emit('prefinish')
+      this.emit('finish')
+      if (this[CLOSED]) this.emit('close')
+      this[EMITTING_END] = false
+    }
+  }
+
+  emit(ev, data, ...extra) {
+    // error and close are only events allowed after calling destroy()
+    if (ev !== 'error' && ev !== 'close' && ev !== DESTROYED && this[DESTROYED])
+      return
+    else if (ev === 'data') {
+      return !this[OBJECTMODE] && !data
+        ? false
+        : this[ASYNC]
+        ? defer(() => this[EMITDATA](data))
+        : this[EMITDATA](data)
+    } else if (ev === 'end') {
+      return this[EMITEND]()
+    } else if (ev === 'close') {
+      this[CLOSED] = true
+      // don't emit close before 'end' and 'finish'
+      if (!this[EMITTED_END] && !this[DESTROYED]) return
+      const ret = super.emit('close')
+      this.removeAllListeners('close')
+      return ret
+    } else if (ev === 'error') {
+      this[EMITTED_ERROR] = data
+      super.emit(ERROR, data)
+      const ret =
+        !this[SIGNAL] || this.listeners('error').length
+          ? super.emit('error', data)
+          : false
+      this[MAYBE_EMIT_END]()
+      return ret
+    } else if (ev === 'resume') {
+      const ret = super.emit('resume')
+      this[MAYBE_EMIT_END]()
+      return ret
+    } else if (ev === 'finish' || ev === 'prefinish') {
+      const ret = super.emit(ev)
+      this.removeAllListeners(ev)
+      return ret
+    }
+
+    // Some other unknown event
+    const ret = super.emit(ev, data, ...extra)
+    this[MAYBE_EMIT_END]()
+    return ret
+  }
+
+  [EMITDATA](data) {
+    for (const p of this[PIPES]) {
+      if (p.dest.write(data) === false) this.pause()
+    }
+    const ret = super.emit('data', data)
+    this[MAYBE_EMIT_END]()
+    return ret
+  }
+
+  [EMITEND]() {
+    if (this[EMITTED_END]) return
+
+    this[EMITTED_END] = true
+    this.readable = false
+    if (this[ASYNC]) defer(() => this[EMITEND2]())
+    else this[EMITEND2]()
+  }
+
+  [EMITEND2]() {
+    if (this[DECODER]) {
+      const data = this[DECODER].end()
+      if (data) {
+        for (const p of this[PIPES]) {
+          p.dest.write(data)
+        }
+        super.emit('data', data)
+      }
+    }
+
+    for (const p of this[PIPES]) {
+      p.end()
+    }
+    const ret = super.emit('end')
+    this.removeAllListeners('end')
+    return ret
+  }
+
+  // const all = await stream.collect()
+  collect() {
+    const buf = []
+    if (!this[OBJECTMODE]) buf.dataLength = 0
+    // set the promise first, in case an error is raised
+    // by triggering the flow here.
+    const p = this.promise()
+    this.on('data', c => {
+      buf.push(c)
+      if (!this[OBJECTMODE]) buf.dataLength += c.length
+    })
+    return p.then(() => buf)
+  }
+
+  // const data = await stream.concat()
+  concat() {
+    return this[OBJECTMODE]
+      ? Promise.reject(new Error('cannot concat in objectMode'))
+      : this.collect().then(buf =>
+          this[OBJECTMODE]
+            ? Promise.reject(new Error('cannot concat in objectMode'))
+            : this[ENCODING]
+            ? buf.join('')
+            : Buffer.concat(buf, buf.dataLength)
+        )
+  }
+
+  // stream.promise().then(() => done, er => emitted error)
+  promise() {
+    return new Promise((resolve, reject) => {
+      this.on(DESTROYED, () => reject(new Error('stream destroyed')))
+      this.on('error', er => reject(er))
+      this.on('end', () => resolve())
+    })
+  }
+
+  // for await (let chunk of stream)
+  [ASYNCITERATOR]() {
+    let stopped = false
+    const stop = () => {
+      this.pause()
+      stopped = true
+      return Promise.resolve({ done: true })
+    }
+    const next = () => {
+      if (stopped) return stop()
+      const res = this.read()
+      if (res !== null) return Promise.resolve({ done: false, value: res })
+
+      if (this[EOF]) return stop()
+
+      let resolve = null
+      let reject = null
+      const onerr = er => {
+        this.removeListener('data', ondata)
+        this.removeListener('end', onend)
+        this.removeListener(DESTROYED, ondestroy)
+        stop()
+        reject(er)
+      }
+      const ondata = value => {
+        this.removeListener('error', onerr)
+        this.removeListener('end', onend)
+        this.removeListener(DESTROYED, ondestroy)
+        this.pause()
+        resolve({ value: value, done: !!this[EOF] })
+      }
+      const onend = () => {
+        this.removeListener('error', onerr)
+        this.removeListener('data', ondata)
+        this.removeListener(DESTROYED, ondestroy)
+        stop()
+        resolve({ done: true })
+      }
+      const ondestroy = () => onerr(new Error('stream destroyed'))
+      return new Promise((res, rej) => {
+        reject = rej
+        resolve = res
+        this.once(DESTROYED, ondestroy)
+        this.once('error', onerr)
+        this.once('end', onend)
+        this.once('data', ondata)
+      })
+    }
+
+    return {
+      next,
+      throw: stop,
+      return: stop,
+      [ASYNCITERATOR]() {
+        return this
+      },
+    }
+  }
+
+  // for (let chunk of stream)
+  [ITERATOR]() {
+    let stopped = false
+    const stop = () => {
+      this.pause()
+      this.removeListener(ERROR, stop)
+      this.removeListener(DESTROYED, stop)
+      this.removeListener('end', stop)
+      stopped = true
+      return { done: true }
+    }
+
+    const next = () => {
+      if (stopped) return stop()
+      const value = this.read()
+      return value === null ? stop() : { value }
+    }
+    this.once('end', stop)
+    this.once(ERROR, stop)
+    this.once(DESTROYED, stop)
+
+    return {
+      next,
+      throw: stop,
+      return: stop,
+      [ITERATOR]() {
+        return this
+      },
+    }
+  }
+
+  destroy(er) {
+    if (this[DESTROYED]) {
+      if (er) this.emit('error', er)
+      else this.emit(DESTROYED)
+      return this
+    }
+
+    this[DESTROYED] = true
+
+    // throw away all buffered data, it's never coming out
+    this[BUFFER].length = 0
+    this[BUFFERLENGTH] = 0
+
+    if (typeof this.close === 'function' && !this[CLOSED]) this.close()
+
+    if (er) this.emit('error', er)
+    // if no error to emit, still reject pending promises
+    else this.emit(DESTROYED)
+
+    return this
+  }
+
+  static isStream(s) {
+    return (
+      !!s &&
+      (s instanceof Minipass ||
+        s instanceof Stream ||
+        (s instanceof EE &&
+          // readable
+          (typeof s.pipe === 'function' ||
+            // writable
+            (typeof s.write === 'function' && typeof s.end === 'function'))))
+    )
+  }
+}
+
+
diff --git a/server/node_modules/tar/node_modules/minipass/package.json b/server/node_modules/tar/node_modules/minipass/package.json
new file mode 100644
index 0000000..0e20e98
--- /dev/null
+++ b/server/node_modules/tar/node_modules/minipass/package.json
@@ -0,0 +1,76 @@
+{
+  "name": "minipass",
+  "version": "5.0.0",
+  "description": "minimal implementation of a PassThrough stream",
+  "main": "./index.js",
+  "module": "./index.mjs",
+  "types": "./index.d.ts",
+  "exports": {
+    ".": {
+      "import": {
+        "types": "./index.d.ts",
+        "default": "./index.mjs"
+      },
+      "require": {
+        "types": "./index.d.ts",
+        "default": "./index.js"
+      }
+    },
+    "./package.json": "./package.json"
+  },
+  "devDependencies": {
+    "@types/node": "^17.0.41",
+    "end-of-stream": "^1.4.0",
+    "node-abort-controller": "^3.1.1",
+    "prettier": "^2.6.2",
+    "tap": "^16.2.0",
+    "through2": "^2.0.3",
+    "ts-node": "^10.8.1",
+    "typedoc": "^0.23.24",
+    "typescript": "^4.7.3"
+  },
+  "scripts": {
+    "pretest": "npm run prepare",
+    "presnap": "npm run prepare",
+    "prepare": "node ./scripts/transpile-to-esm.js",
+    "snap": "tap",
+    "test": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags",
+    "typedoc": "typedoc ./index.d.ts",
+    "format": "prettier --write . --loglevel warn"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/isaacs/minipass.git"
+  },
+  "keywords": [
+    "passthrough",
+    "stream"
+  ],
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC",
+  "files": [
+    "index.d.ts",
+    "index.js",
+    "index.mjs"
+  ],
+  "tap": {
+    "check-coverage": true
+  },
+  "engines": {
+    "node": ">=8"
+  },
+  "prettier": {
+    "semi": false,
+    "printWidth": 80,
+    "tabWidth": 2,
+    "useTabs": false,
+    "singleQuote": true,
+    "jsxSingleQuote": false,
+    "bracketSameLine": true,
+    "arrowParens": "avoid",
+    "endOfLine": "lf"
+  }
+}
diff --git a/server/node_modules/tar/node_modules/mkdirp/CHANGELOG.md b/server/node_modules/tar/node_modules/mkdirp/CHANGELOG.md
new file mode 100644
index 0000000..8145838
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/CHANGELOG.md
@@ -0,0 +1,15 @@
+# Changers Lorgs!
+
+## 1.0
+
+Full rewrite.  Essentially a brand new module.
+
+- Return a promise instead of taking a callback.
+- Use native `fs.mkdir(path, { recursive: true })` when available.
+- Drop support for outdated Node.js versions.  (Technically still works on
+  Node.js v8, but only 10 and above are officially supported.)
+
+## 0.x
+
+Original and most widely used recursive directory creation implementation
+in JavaScript, dating back to 2010.
diff --git a/server/node_modules/tar/node_modules/mkdirp/LICENSE b/server/node_modules/tar/node_modules/mkdirp/LICENSE
new file mode 100644
index 0000000..13fcd15
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/LICENSE
@@ -0,0 +1,21 @@
+Copyright James Halliday (mail@substack.net) and Isaac Z. Schlueter (i@izs.me)
+
+This project is free software released under the MIT license:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/tar/node_modules/mkdirp/bin/cmd.js b/server/node_modules/tar/node_modules/mkdirp/bin/cmd.js
new file mode 100755
index 0000000..6e0aa8d
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/bin/cmd.js
@@ -0,0 +1,68 @@
+#!/usr/bin/env node
+
+const usage = () => `
+usage: mkdirp [DIR1,DIR2..] {OPTIONS}
+
+  Create each supplied directory including any necessary parent directories
+  that don't yet exist.
+
+  If the directory already exists, do nothing.
+
+OPTIONS are:
+
+  -m<mode>       If a directory needs to be created, set the mode as an octal
+  --mode=<mode>  permission string.
+
+  -v --version   Print the mkdirp version number
+
+  -h --help      Print this helpful banner
+
+  -p --print     Print the first directories created for each path provided
+
+  --manual       Use manual implementation, even if native is available
+`
+
+const dirs = []
+const opts = {}
+let print = false
+let dashdash = false
+let manual = false
+for (const arg of process.argv.slice(2)) {
+  if (dashdash)
+    dirs.push(arg)
+  else if (arg === '--')
+    dashdash = true
+  else if (arg === '--manual')
+    manual = true
+  else if (/^-h/.test(arg) || /^--help/.test(arg)) {
+    console.log(usage())
+    process.exit(0)
+  } else if (arg === '-v' || arg === '--version') {
+    console.log(require('../package.json').version)
+    process.exit(0)
+  } else if (arg === '-p' || arg === '--print') {
+    print = true
+  } else if (/^-m/.test(arg) || /^--mode=/.test(arg)) {
+    const mode = parseInt(arg.replace(/^(-m|--mode=)/, ''), 8)
+    if (isNaN(mode)) {
+      console.error(`invalid mode argument: ${arg}\nMust be an octal number.`)
+      process.exit(1)
+    }
+    opts.mode = mode
+  } else
+    dirs.push(arg)
+}
+
+const mkdirp = require('../')
+const impl = manual ? mkdirp.manual : mkdirp
+if (dirs.length === 0)
+  console.error(usage())
+
+Promise.all(dirs.map(dir => impl(dir, opts)))
+  .then(made => print ? made.forEach(m => m && console.log(m)) : null)
+  .catch(er => {
+    console.error(er.message)
+    if (er.code)
+      console.error('  code: ' + er.code)
+    process.exit(1)
+  })
diff --git a/server/node_modules/tar/node_modules/mkdirp/index.js b/server/node_modules/tar/node_modules/mkdirp/index.js
new file mode 100644
index 0000000..ad7a16c
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/index.js
@@ -0,0 +1,31 @@
+const optsArg = require('./lib/opts-arg.js')
+const pathArg = require('./lib/path-arg.js')
+
+const {mkdirpNative, mkdirpNativeSync} = require('./lib/mkdirp-native.js')
+const {mkdirpManual, mkdirpManualSync} = require('./lib/mkdirp-manual.js')
+const {useNative, useNativeSync} = require('./lib/use-native.js')
+
+
+const mkdirp = (path, opts) => {
+  path = pathArg(path)
+  opts = optsArg(opts)
+  return useNative(opts)
+    ? mkdirpNative(path, opts)
+    : mkdirpManual(path, opts)
+}
+
+const mkdirpSync = (path, opts) => {
+  path = pathArg(path)
+  opts = optsArg(opts)
+  return useNativeSync(opts)
+    ? mkdirpNativeSync(path, opts)
+    : mkdirpManualSync(path, opts)
+}
+
+mkdirp.sync = mkdirpSync
+mkdirp.native = (path, opts) => mkdirpNative(pathArg(path), optsArg(opts))
+mkdirp.manual = (path, opts) => mkdirpManual(pathArg(path), optsArg(opts))
+mkdirp.nativeSync = (path, opts) => mkdirpNativeSync(pathArg(path), optsArg(opts))
+mkdirp.manualSync = (path, opts) => mkdirpManualSync(pathArg(path), optsArg(opts))
+
+module.exports = mkdirp
diff --git a/server/node_modules/tar/node_modules/mkdirp/lib/find-made.js b/server/node_modules/tar/node_modules/mkdirp/lib/find-made.js
new file mode 100644
index 0000000..022e492
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/lib/find-made.js
@@ -0,0 +1,29 @@
+const {dirname} = require('path')
+
+const findMade = (opts, parent, path = undefined) => {
+  // we never want the 'made' return value to be a root directory
+  if (path === parent)
+    return Promise.resolve()
+
+  return opts.statAsync(parent).then(
+    st => st.isDirectory() ? path : undefined, // will fail later
+    er => er.code === 'ENOENT'
+      ? findMade(opts, dirname(parent), parent)
+      : undefined
+  )
+}
+
+const findMadeSync = (opts, parent, path = undefined) => {
+  if (path === parent)
+    return undefined
+
+  try {
+    return opts.statSync(parent).isDirectory() ? path : undefined
+  } catch (er) {
+    return er.code === 'ENOENT'
+      ? findMadeSync(opts, dirname(parent), parent)
+      : undefined
+  }
+}
+
+module.exports = {findMade, findMadeSync}
diff --git a/server/node_modules/tar/node_modules/mkdirp/lib/mkdirp-manual.js b/server/node_modules/tar/node_modules/mkdirp/lib/mkdirp-manual.js
new file mode 100644
index 0000000..2eb18cd
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/lib/mkdirp-manual.js
@@ -0,0 +1,64 @@
+const {dirname} = require('path')
+
+const mkdirpManual = (path, opts, made) => {
+  opts.recursive = false
+  const parent = dirname(path)
+  if (parent === path) {
+    return opts.mkdirAsync(path, opts).catch(er => {
+      // swallowed by recursive implementation on posix systems
+      // any other error is a failure
+      if (er.code !== 'EISDIR')
+        throw er
+    })
+  }
+
+  return opts.mkdirAsync(path, opts).then(() => made || path, er => {
+    if (er.code === 'ENOENT')
+      return mkdirpManual(parent, opts)
+        .then(made => mkdirpManual(path, opts, made))
+    if (er.code !== 'EEXIST' && er.code !== 'EROFS')
+      throw er
+    return opts.statAsync(path).then(st => {
+      if (st.isDirectory())
+        return made
+      else
+        throw er
+    }, () => { throw er })
+  })
+}
+
+const mkdirpManualSync = (path, opts, made) => {
+  const parent = dirname(path)
+  opts.recursive = false
+
+  if (parent === path) {
+    try {
+      return opts.mkdirSync(path, opts)
+    } catch (er) {
+      // swallowed by recursive implementation on posix systems
+      // any other error is a failure
+      if (er.code !== 'EISDIR')
+        throw er
+      else
+        return
+    }
+  }
+
+  try {
+    opts.mkdirSync(path, opts)
+    return made || path
+  } catch (er) {
+    if (er.code === 'ENOENT')
+      return mkdirpManualSync(path, opts, mkdirpManualSync(parent, opts, made))
+    if (er.code !== 'EEXIST' && er.code !== 'EROFS')
+      throw er
+    try {
+      if (!opts.statSync(path).isDirectory())
+        throw er
+    } catch (_) {
+      throw er
+    }
+  }
+}
+
+module.exports = {mkdirpManual, mkdirpManualSync}
diff --git a/server/node_modules/tar/node_modules/mkdirp/lib/mkdirp-native.js b/server/node_modules/tar/node_modules/mkdirp/lib/mkdirp-native.js
new file mode 100644
index 0000000..c7a6b69
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/lib/mkdirp-native.js
@@ -0,0 +1,39 @@
+const {dirname} = require('path')
+const {findMade, findMadeSync} = require('./find-made.js')
+const {mkdirpManual, mkdirpManualSync} = require('./mkdirp-manual.js')
+
+const mkdirpNative = (path, opts) => {
+  opts.recursive = true
+  const parent = dirname(path)
+  if (parent === path)
+    return opts.mkdirAsync(path, opts)
+
+  return findMade(opts, path).then(made =>
+    opts.mkdirAsync(path, opts).then(() => made)
+    .catch(er => {
+      if (er.code === 'ENOENT')
+        return mkdirpManual(path, opts)
+      else
+        throw er
+    }))
+}
+
+const mkdirpNativeSync = (path, opts) => {
+  opts.recursive = true
+  const parent = dirname(path)
+  if (parent === path)
+    return opts.mkdirSync(path, opts)
+
+  const made = findMadeSync(opts, path)
+  try {
+    opts.mkdirSync(path, opts)
+    return made
+  } catch (er) {
+    if (er.code === 'ENOENT')
+      return mkdirpManualSync(path, opts)
+    else
+      throw er
+  }
+}
+
+module.exports = {mkdirpNative, mkdirpNativeSync}
diff --git a/server/node_modules/tar/node_modules/mkdirp/lib/opts-arg.js b/server/node_modules/tar/node_modules/mkdirp/lib/opts-arg.js
new file mode 100644
index 0000000..2fa4833
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/lib/opts-arg.js
@@ -0,0 +1,23 @@
+const { promisify } = require('util')
+const fs = require('fs')
+const optsArg = opts => {
+  if (!opts)
+    opts = { mode: 0o777, fs }
+  else if (typeof opts === 'object')
+    opts = { mode: 0o777, fs, ...opts }
+  else if (typeof opts === 'number')
+    opts = { mode: opts, fs }
+  else if (typeof opts === 'string')
+    opts = { mode: parseInt(opts, 8), fs }
+  else
+    throw new TypeError('invalid options argument')
+
+  opts.mkdir = opts.mkdir || opts.fs.mkdir || fs.mkdir
+  opts.mkdirAsync = promisify(opts.mkdir)
+  opts.stat = opts.stat || opts.fs.stat || fs.stat
+  opts.statAsync = promisify(opts.stat)
+  opts.statSync = opts.statSync || opts.fs.statSync || fs.statSync
+  opts.mkdirSync = opts.mkdirSync || opts.fs.mkdirSync || fs.mkdirSync
+  return opts
+}
+module.exports = optsArg
diff --git a/server/node_modules/tar/node_modules/mkdirp/lib/path-arg.js b/server/node_modules/tar/node_modules/mkdirp/lib/path-arg.js
new file mode 100644
index 0000000..cc07de5
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/lib/path-arg.js
@@ -0,0 +1,29 @@
+const platform = process.env.__TESTING_MKDIRP_PLATFORM__ || process.platform
+const { resolve, parse } = require('path')
+const pathArg = path => {
+  if (/\0/.test(path)) {
+    // simulate same failure that node raises
+    throw Object.assign(
+      new TypeError('path must be a string without null bytes'),
+      {
+        path,
+        code: 'ERR_INVALID_ARG_VALUE',
+      }
+    )
+  }
+
+  path = resolve(path)
+  if (platform === 'win32') {
+    const badWinChars = /[*|"<>?:]/
+    const {root} = parse(path)
+    if (badWinChars.test(path.substr(root.length))) {
+      throw Object.assign(new Error('Illegal characters in path.'), {
+        path,
+        code: 'EINVAL',
+      })
+    }
+  }
+
+  return path
+}
+module.exports = pathArg
diff --git a/server/node_modules/tar/node_modules/mkdirp/lib/use-native.js b/server/node_modules/tar/node_modules/mkdirp/lib/use-native.js
new file mode 100644
index 0000000..079361d
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/lib/use-native.js
@@ -0,0 +1,10 @@
+const fs = require('fs')
+
+const version = process.env.__TESTING_MKDIRP_NODE_VERSION__ || process.version
+const versArr = version.replace(/^v/, '').split('.')
+const hasNative = +versArr[0] > 10 || +versArr[0] === 10 && +versArr[1] >= 12
+
+const useNative = !hasNative ? () => false : opts => opts.mkdir === fs.mkdir
+const useNativeSync = !hasNative ? () => false : opts => opts.mkdirSync === fs.mkdirSync
+
+module.exports = {useNative, useNativeSync}
diff --git a/server/node_modules/tar/node_modules/mkdirp/package.json b/server/node_modules/tar/node_modules/mkdirp/package.json
new file mode 100644
index 0000000..2913ed0
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "mkdirp",
+  "description": "Recursively mkdir, like `mkdir -p`",
+  "version": "1.0.4",
+  "main": "index.js",
+  "keywords": [
+    "mkdir",
+    "directory",
+    "make dir",
+    "make",
+    "dir",
+    "recursive",
+    "native"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/isaacs/node-mkdirp.git"
+  },
+  "scripts": {
+    "test": "tap",
+    "snap": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "tap": {
+    "check-coverage": true,
+    "coverage-map": "map.js"
+  },
+  "devDependencies": {
+    "require-inject": "^1.4.4",
+    "tap": "^14.10.7"
+  },
+  "bin": "bin/cmd.js",
+  "license": "MIT",
+  "engines": {
+    "node": ">=10"
+  },
+  "files": [
+    "bin",
+    "lib",
+    "index.js"
+  ]
+}
diff --git a/server/node_modules/tar/node_modules/mkdirp/readme.markdown b/server/node_modules/tar/node_modules/mkdirp/readme.markdown
new file mode 100644
index 0000000..827de59
--- /dev/null
+++ b/server/node_modules/tar/node_modules/mkdirp/readme.markdown
@@ -0,0 +1,266 @@
+# mkdirp
+
+Like `mkdir -p`, but in Node.js!
+
+Now with a modern API and no\* bugs!
+
+<small>\* may contain some bugs</small>
+
+# example
+
+## pow.js
+
+```js
+const mkdirp = require('mkdirp')
+
+// return value is a Promise resolving to the first directory created
+mkdirp('/tmp/foo/bar/baz').then(made =>
+  console.log(`made directories, starting with ${made}`))
+```
+
+Output (where `/tmp/foo` already exists)
+
+```
+made directories, starting with /tmp/foo/bar
+```
+
+Or, if you don't have time to wait around for promises:
+
+```js
+const mkdirp = require('mkdirp')
+
+// return value is the first directory created
+const made = mkdirp.sync('/tmp/foo/bar/baz')
+console.log(`made directories, starting with ${made}`)
+```
+
+And now /tmp/foo/bar/baz exists, huzzah!
+
+# methods
+
+```js
+const mkdirp = require('mkdirp')
+```
+
+## mkdirp(dir, [opts]) -> Promise<String | undefined>
+
+Create a new directory and any necessary subdirectories at `dir` with octal
+permission string `opts.mode`. If `opts` is a string or number, it will be
+treated as the `opts.mode`.
+
+If `opts.mode` isn't specified, it defaults to `0o777 &
+(~process.umask())`.
+
+Promise resolves to first directory `made` that had to be created, or
+`undefined` if everything already exists.  Promise rejects if any errors
+are encountered.  Note that, in the case of promise rejection, some
+directories _may_ have been created, as recursive directory creation is not
+an atomic operation.
+
+You can optionally pass in an alternate `fs` implementation by passing in
+`opts.fs`. Your implementation should have `opts.fs.mkdir(path, opts, cb)`
+and `opts.fs.stat(path, cb)`.
+
+You can also override just one or the other of `mkdir` and `stat` by
+passing in `opts.stat` or `opts.mkdir`, or providing an `fs` option that
+only overrides one of these.
+
+## mkdirp.sync(dir, opts) -> String|null
+
+Synchronously create a new directory and any necessary subdirectories at
+`dir` with octal permission string `opts.mode`. If `opts` is a string or
+number, it will be treated as the `opts.mode`.
+
+If `opts.mode` isn't specified, it defaults to `0o777 &
+(~process.umask())`.
+
+Returns the first directory that had to be created, or undefined if
+everything already exists.
+
+You can optionally pass in an alternate `fs` implementation by passing in
+`opts.fs`. Your implementation should have `opts.fs.mkdirSync(path, mode)`
+and `opts.fs.statSync(path)`.
+
+You can also override just one or the other of `mkdirSync` and `statSync`
+by passing in `opts.statSync` or `opts.mkdirSync`, or providing an `fs`
+option that only overrides one of these.
+
+## mkdirp.manual, mkdirp.manualSync
+
+Use the manual implementation (not the native one).  This is the default
+when the native implementation is not available or the stat/mkdir
+implementation is overridden.
+
+## mkdirp.native, mkdirp.nativeSync
+
+Use the native implementation (not the manual one).  This is the default
+when the native implementation is available and stat/mkdir are not
+overridden.
+
+# implementation
+
+On Node.js v10.12.0 and above, use the native `fs.mkdir(p,
+{recursive:true})` option, unless `fs.mkdir`/`fs.mkdirSync` has been
+overridden by an option.
+
+## native implementation
+
+- If the path is a root directory, then pass it to the underlying
+  implementation and return the result/error.  (In this case, it'll either
+  succeed or fail, but we aren't actually creating any dirs.)
+- Walk up the path statting each directory, to find the first path that
+  will be created, `made`.
+- Call `fs.mkdir(path, { recursive: true })` (or `fs.mkdirSync`)
+- If error, raise it to the caller.
+- Return `made`.
+
+## manual implementation
+
+- Call underlying `fs.mkdir` implementation, with `recursive: false`
+- If error:
+  - If path is a root directory, raise to the caller and do not handle it
+  - If ENOENT, mkdirp parent dir, store result as `made`
+  - stat(path)
+    - If error, raise original `mkdir` error
+    - If directory, return `made`
+    - Else, raise original `mkdir` error
+- else
+  - return `undefined` if a root dir, or `made` if set, or `path`
+
+## windows vs unix caveat
+
+On Windows file systems, attempts to create a root directory (ie, a drive
+letter or root UNC path) will fail.  If the root directory exists, then it
+will fail with `EPERM`.  If the root directory does not exist, then it will
+fail with `ENOENT`.
+
+On posix file systems, attempts to create a root directory (in recursive
+mode) will succeed silently, as it is treated like just another directory
+that already exists.  (In non-recursive mode, of course, it fails with
+`EEXIST`.)
+
+In order to preserve this system-specific behavior (and because it's not as
+if we can create the parent of a root directory anyway), attempts to create
+a root directory are passed directly to the `fs` implementation, and any
+errors encountered are not handled.
+
+## native error caveat
+
+The native implementation (as of at least Node.js v13.4.0) does not provide
+appropriate errors in some cases (see
+[nodejs/node#31481](https://github.com/nodejs/node/issues/31481) and
+[nodejs/node#28015](https://github.com/nodejs/node/issues/28015)).
+
+In order to work around this issue, the native implementation will fall
+back to the manual implementation if an `ENOENT` error is encountered.
+
+# choosing a recursive mkdir implementation
+
+There are a few to choose from!  Use the one that suits your needs best :D
+
+## use `fs.mkdir(path, {recursive: true}, cb)` if:
+
+- You wish to optimize performance even at the expense of other factors.
+- You don't need to know the first dir created.
+- You are ok with getting `ENOENT` as the error when some other problem is
+  the actual cause.
+- You can limit your platforms to Node.js v10.12 and above.
+- You're ok with using callbacks instead of promises.
+- You don't need/want a CLI.
+- You don't need to override the `fs` methods in use.
+
+## use this module (mkdirp 1.x) if:
+
+- You need to know the first directory that was created.
+- You wish to use the native implementation if available, but fall back
+  when it's not.
+- You prefer promise-returning APIs to callback-taking APIs.
+- You want more useful error messages than the native recursive mkdir
+  provides (at least as of Node.js v13.4), and are ok with re-trying on
+  `ENOENT` to achieve this.
+- You need (or at least, are ok with) a CLI.
+- You need to override the `fs` methods in use.
+
+## use [`make-dir`](http://npm.im/make-dir) if:
+
+- You do not need to know the first dir created (and wish to save a few
+  `stat` calls when using the native implementation for this reason).
+- You wish to use the native implementation if available, but fall back
+  when it's not.
+- You prefer promise-returning APIs to callback-taking APIs.
+- You are ok with occasionally getting `ENOENT` errors for failures that
+  are actually related to something other than a missing file system entry.
+- You don't need/want a CLI.
+- You need to override the `fs` methods in use.
+
+## use mkdirp 0.x if:
+
+- You need to know the first directory that was created.
+- You need (or at least, are ok with) a CLI.
+- You need to override the `fs` methods in use.
+- You're ok with using callbacks instead of promises.
+- You are not running on Windows, where the root-level ENOENT errors can
+  lead to infinite regress.
+- You think vinyl just sounds warmer and richer for some weird reason.
+- You are supporting truly ancient Node.js versions, before even the advent
+  of a `Promise` language primitive.  (Please don't.  You deserve better.)
+
+# cli
+
+This package also ships with a `mkdirp` command.
+
+```
+$ mkdirp -h
+
+usage: mkdirp [DIR1,DIR2..] {OPTIONS}
+
+  Create each supplied directory including any necessary parent directories
+  that don't yet exist.
+
+  If the directory already exists, do nothing.
+
+OPTIONS are:
+
+  -m<mode>       If a directory needs to be created, set the mode as an octal
+  --mode=<mode>  permission string.
+
+  -v --version   Print the mkdirp version number
+
+  -h --help      Print this helpful banner
+
+  -p --print     Print the first directories created for each path provided
+
+  --manual       Use manual implementation, even if native is available
+```
+
+# install
+
+With [npm](http://npmjs.org) do:
+
+```
+npm install mkdirp
+```
+
+to get the library locally, or
+
+```
+npm install -g mkdirp
+```
+
+to get the command everywhere, or
+
+```
+npx mkdirp ...
+```
+
+to run the command without installing it globally.
+
+# platform support
+
+This module works on node v8, but only v10 and above are officially
+supported, as Node v8 reached its LTS end of life 2020-01-01, which is in
+the past, as of this writing.
+
+# license
+
+MIT
diff --git a/server/node_modules/tar/package.json b/server/node_modules/tar/package.json
new file mode 100644
index 0000000..f84a41c
--- /dev/null
+++ b/server/node_modules/tar/package.json
@@ -0,0 +1,70 @@
+{
+  "author": "GitHub Inc.",
+  "name": "tar",
+  "description": "tar for node",
+  "version": "6.2.1",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/isaacs/node-tar.git"
+  },
+  "scripts": {
+    "genparse": "node scripts/generate-parse-fixtures.js",
+    "snap": "tap",
+    "test": "tap"
+  },
+  "dependencies": {
+    "chownr": "^2.0.0",
+    "fs-minipass": "^2.0.0",
+    "minipass": "^5.0.0",
+    "minizlib": "^2.1.1",
+    "mkdirp": "^1.0.3",
+    "yallist": "^4.0.0"
+  },
+  "devDependencies": {
+    "@npmcli/eslint-config": "^4.0.0",
+    "@npmcli/template-oss": "4.11.0",
+    "chmodr": "^1.2.0",
+    "end-of-stream": "^1.4.3",
+    "events-to-array": "^2.0.3",
+    "mutate-fs": "^2.1.1",
+    "nock": "^13.2.9",
+    "rimraf": "^3.0.2",
+    "tap": "^16.0.1"
+  },
+  "license": "ISC",
+  "engines": {
+    "node": ">=10"
+  },
+  "files": [
+    "bin/",
+    "lib/",
+    "index.js"
+  ],
+  "tap": {
+    "coverage-map": "map.js",
+    "timeout": 0,
+    "nyc-arg": [
+      "--exclude",
+      "tap-snapshots/**"
+    ]
+  },
+  "templateOSS": {
+    "//@npmcli/template-oss": "This file is partially managed by @npmcli/template-oss. Edits may be overwritten.",
+    "version": "4.11.0",
+    "content": "scripts/template-oss",
+    "engines": ">=10",
+    "distPaths": [
+      "index.js"
+    ],
+    "allowPaths": [
+      "/index.js"
+    ],
+    "ciVersions": [
+      "10.x",
+      "12.x",
+      "14.x",
+      "16.x",
+      "18.x"
+    ]
+  }
+}
diff --git a/server/node_modules/toidentifier/HISTORY.md b/server/node_modules/toidentifier/HISTORY.md
new file mode 100644
index 0000000..cb7cc89
--- /dev/null
+++ b/server/node_modules/toidentifier/HISTORY.md
@@ -0,0 +1,9 @@
+1.0.1 / 2021-11-14
+==================
+
+  * pref: enable strict mode
+
+1.0.0 / 2018-07-09
+==================
+
+  * Initial release
diff --git a/server/node_modules/toidentifier/LICENSE b/server/node_modules/toidentifier/LICENSE
new file mode 100644
index 0000000..de22d15
--- /dev/null
+++ b/server/node_modules/toidentifier/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2016 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/server/node_modules/toidentifier/README.md b/server/node_modules/toidentifier/README.md
new file mode 100644
index 0000000..57e8a78
--- /dev/null
+++ b/server/node_modules/toidentifier/README.md
@@ -0,0 +1,61 @@
+# toidentifier
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Build Status][github-actions-ci-image]][github-actions-ci-url]
+[![Test Coverage][codecov-image]][codecov-url]
+
+> Convert a string of words to a JavaScript identifier
+
+## Install
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```bash
+$ npm install toidentifier
+```
+
+## Example
+
+```js
+var toIdentifier = require('toidentifier')
+
+console.log(toIdentifier('Bad Request'))
+// => "BadRequest"
+```
+
+## API
+
+This CommonJS module exports a single default function: `toIdentifier`.
+
+### toIdentifier(string)
+
+Given a string as the argument, it will be transformed according to
+the following rules and the new string will be returned:
+
+1. Split into words separated by space characters (`0x20`).
+2. Upper case the first character of each word.
+3. Join the words together with no separator.
+4. Remove all non-word (`[0-9a-z_]`) characters.
+
+## License
+
+[MIT](LICENSE)
+
+[codecov-image]: https://img.shields.io/codecov/c/github/component/toidentifier.svg
+[codecov-url]: https://codecov.io/gh/component/toidentifier
+[downloads-image]: https://img.shields.io/npm/dm/toidentifier.svg
+[downloads-url]: https://npmjs.org/package/toidentifier
+[github-actions-ci-image]: https://img.shields.io/github/workflow/status/component/toidentifier/ci/master?label=ci
+[github-actions-ci-url]: https://github.com/component/toidentifier?query=workflow%3Aci
+[npm-image]: https://img.shields.io/npm/v/toidentifier.svg
+[npm-url]: https://npmjs.org/package/toidentifier
+
+
+##
+
+[npm]: https://www.npmjs.com/
+
+[yarn]: https://yarnpkg.com/
diff --git a/server/node_modules/toidentifier/index.js b/server/node_modules/toidentifier/index.js
new file mode 100644
index 0000000..9295d02
--- /dev/null
+++ b/server/node_modules/toidentifier/index.js
@@ -0,0 +1,32 @@
+/*!
+ * toidentifier
+ * Copyright(c) 2016 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = toIdentifier
+
+/**
+ * Trasform the given string into a JavaScript identifier
+ *
+ * @param {string} str
+ * @returns {string}
+ * @public
+ */
+
+function toIdentifier (str) {
+  return str
+    .split(' ')
+    .map(function (token) {
+      return token.slice(0, 1).toUpperCase() + token.slice(1)
+    })
+    .join('')
+    .replace(/[^ _0-9a-z]/gi, '')
+}
diff --git a/server/node_modules/toidentifier/package.json b/server/node_modules/toidentifier/package.json
new file mode 100644
index 0000000..42db1a6
--- /dev/null
+++ b/server/node_modules/toidentifier/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "toidentifier",
+  "description": "Convert a string of words to a JavaScript identifier",
+  "version": "1.0.1",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Nick Baugh <niftylettuce@gmail.com> (http://niftylettuce.com/)"
+  ],
+  "repository": "component/toidentifier",
+  "devDependencies": {
+    "eslint": "7.32.0",
+    "eslint-config-standard": "14.1.1",
+    "eslint-plugin-import": "2.25.3",
+    "eslint-plugin-markdown": "2.2.1",
+    "eslint-plugin-node": "11.1.0",
+    "eslint-plugin-promise": "4.3.1",
+    "eslint-plugin-standard": "4.1.0",
+    "mocha": "9.1.3",
+    "nyc": "15.1.0"
+  },
+  "engines": {
+    "node": ">=0.6"
+  },
+  "license": "MIT",
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "index.js"
+  ],
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  }
+}
diff --git a/server/node_modules/tunnel-agent/LICENSE b/server/node_modules/tunnel-agent/LICENSE
new file mode 100644
index 0000000..a4a9aee
--- /dev/null
+++ b/server/node_modules/tunnel-agent/LICENSE
@@ -0,0 +1,55 @@
+Apache License
+
+Version 2.0, January 2004
+
+http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
+
+"License" shall mean the terms and conditions for use, reproduction, and distribution as defined by Sections 1 through 9 of this document.
+
+"Licensor" shall mean the copyright owner or entity authorized by the copyright owner that is granting the License.
+
+"Legal Entity" shall mean the union of the acting entity and all other entities that control, are controlled by, or are under common control with that entity. For the purposes of this definition, "control" means (i) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (ii) ownership of fifty percent (50%) or more of the outstanding shares, or (iii) beneficial ownership of such entity.
+
+"You" (or "Your") shall mean an individual or Legal Entity exercising permissions granted by this License.
+
+"Source" form shall mean the preferred form for making modifications, including but not limited to software source code, documentation source, and configuration files.
+
+"Object" form shall mean any form resulting from mechanical transformation or translation of a Source form, including but not limited to compiled object code, generated documentation, and conversions to other media types.
+
+"Work" shall mean the work of authorship, whether in Source or Object form, made available under the License, as indicated by a copyright notice that is included in or attached to the work (an example is provided in the Appendix below).
+
+"Derivative Works" shall mean any work, whether in Source or Object form, that is based on (or derived from) the Work and for which the editorial revisions, annotations, elaborations, or other modifications represent, as a whole, an original work of authorship. For the purposes of this License, Derivative Works shall not include works that remain separable from, or merely link (or bind by name) to the interfaces of, the Work and Derivative Works thereof.
+
+"Contribution" shall mean any work of authorship, including the original version of the Work and any modifications or additions to that Work or Derivative Works thereof, that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner. For the purposes of this definition, "submitted" means any form of electronic, verbal, or written communication sent to the Licensor or its representatives, including but not limited to communication on electronic mailing lists, source code control systems, and issue tracking systems that are managed by, or on behalf of, the Licensor for the purpose of discussing and improving the Work, but excluding communication that is conspicuously marked or otherwise designated in writing by the copyright owner as "Not a Contribution."
+
+"Contributor" shall mean Licensor and any individual or Legal Entity on behalf of whom a Contribution has been received by Licensor and subsequently incorporated within the Work.
+
+2. Grant of Copyright License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare Derivative Works of, publicly display, publicly perform, sublicense, and distribute the Work and such Derivative Works in Source or Object form.
+
+3. Grant of Patent License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work, where such license applies only to those patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s) alone or by combination of their Contribution(s) with the Work to which such Contribution(s) was submitted. If You institute patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that the Work or a Contribution incorporated within the Work constitutes direct or contributory patent infringement, then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed.
+
+4. Redistribution. You may reproduce and distribute copies of the Work or Derivative Works thereof in any medium, with or without modifications, and in Source or Object form, provided that You meet the following conditions:
+
+You must give any other recipients of the Work or Derivative Works a copy of this License; and
+
+You must cause any modified files to carry prominent notices stating that You changed the files; and
+
+You must retain, in the Source form of any Derivative Works that You distribute, all copyright, patent, trademark, and attribution notices from the Source form of the Work, excluding those notices that do not pertain to any part of the Derivative Works; and
+
+If the Work includes a "NOTICE" text file as part of its distribution, then any Derivative Works that You distribute must include a readable copy of the attribution notices contained within such NOTICE file, excluding those notices that do not pertain to any part of the Derivative Works, in at least one of the following places: within a NOTICE text file distributed as part of the Derivative Works; within the Source form or documentation, if provided along with the Derivative Works; or, within a display generated by the Derivative Works, if and wherever such third-party notices normally appear. The contents of the NOTICE file are for informational purposes only and do not modify the License. You may add Your own attribution notices within Derivative Works that You distribute, alongside or as an addendum to the NOTICE text from the Work, provided that such additional attribution notices cannot be construed as modifying the License. You may add Your own copyright statement to Your modifications and may provide additional or different license terms and conditions for use, reproduction, or distribution of Your modifications, or for any such Derivative Works as a whole, provided Your use, reproduction, and distribution of the Work otherwise complies with the conditions stated in this License.
+
+5. Submission of Contributions. Unless You explicitly state otherwise, any Contribution intentionally submitted for inclusion in the Work by You to the Licensor shall be under the terms and conditions of this License, without any additional terms or conditions. Notwithstanding the above, nothing herein shall supersede or modify the terms of any separate license agreement you may have executed with Licensor regarding such Contributions.
+
+6. Trademarks. This License does not grant permission to use the trade names, trademarks, service marks, or product names of the Licensor, except as required for reasonable and customary use in describing the origin of the Work and reproducing the content of the NOTICE file.
+
+7. Disclaimer of Warranty. Unless required by applicable law or agreed to in writing, Licensor provides the Work (and each Contributor provides its Contributions) on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. You are solely responsible for determining the appropriateness of using or redistributing the Work and assume any risks associated with Your exercise of permissions under this License.
+
+8. Limitation of Liability. In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall any Contributor be liable to You for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising as a result of this License or out of the use or inability to use the Work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if such Contributor has been advised of the possibility of such damages.
+
+9. Accepting Warranty or Additional Liability. While redistributing the Work or Derivative Works thereof, You may choose to offer, and charge a fee for, acceptance of support, warranty, indemnity, or other liability obligations and/or rights consistent with this License. However, in accepting such obligations, You may act only on Your own behalf and on Your sole responsibility, not on behalf of any other Contributor, and only if You agree to indemnify, defend, and hold each Contributor harmless for any liability incurred by, or claims asserted against, such Contributor by reason of your accepting any such warranty or additional liability.
+
+END OF TERMS AND CONDITIONS
\ No newline at end of file
diff --git a/server/node_modules/tunnel-agent/README.md b/server/node_modules/tunnel-agent/README.md
new file mode 100644
index 0000000..bb533d5
--- /dev/null
+++ b/server/node_modules/tunnel-agent/README.md
@@ -0,0 +1,4 @@
+tunnel-agent
+============
+
+HTTP proxy tunneling agent. Formerly part of mikeal/request, now a standalone module.
diff --git a/server/node_modules/tunnel-agent/index.js b/server/node_modules/tunnel-agent/index.js
new file mode 100644
index 0000000..3ee9abc
--- /dev/null
+++ b/server/node_modules/tunnel-agent/index.js
@@ -0,0 +1,244 @@
+'use strict'
+
+var net = require('net')
+  , tls = require('tls')
+  , http = require('http')
+  , https = require('https')
+  , events = require('events')
+  , assert = require('assert')
+  , util = require('util')
+  , Buffer = require('safe-buffer').Buffer
+  ;
+
+exports.httpOverHttp = httpOverHttp
+exports.httpsOverHttp = httpsOverHttp
+exports.httpOverHttps = httpOverHttps
+exports.httpsOverHttps = httpsOverHttps
+
+
+function httpOverHttp(options) {
+  var agent = new TunnelingAgent(options)
+  agent.request = http.request
+  return agent
+}
+
+function httpsOverHttp(options) {
+  var agent = new TunnelingAgent(options)
+  agent.request = http.request
+  agent.createSocket = createSecureSocket
+  agent.defaultPort = 443
+  return agent
+}
+
+function httpOverHttps(options) {
+  var agent = new TunnelingAgent(options)
+  agent.request = https.request
+  return agent
+}
+
+function httpsOverHttps(options) {
+  var agent = new TunnelingAgent(options)
+  agent.request = https.request
+  agent.createSocket = createSecureSocket
+  agent.defaultPort = 443
+  return agent
+}
+
+
+function TunnelingAgent(options) {
+  var self = this
+  self.options = options || {}
+  self.proxyOptions = self.options.proxy || {}
+  self.maxSockets = self.options.maxSockets || http.Agent.defaultMaxSockets
+  self.requests = []
+  self.sockets = []
+
+  self.on('free', function onFree(socket, host, port) {
+    for (var i = 0, len = self.requests.length; i < len; ++i) {
+      var pending = self.requests[i]
+      if (pending.host === host && pending.port === port) {
+        // Detect the request to connect same origin server,
+        // reuse the connection.
+        self.requests.splice(i, 1)
+        pending.request.onSocket(socket)
+        return
+      }
+    }
+    socket.destroy()
+    self.removeSocket(socket)
+  })
+}
+util.inherits(TunnelingAgent, events.EventEmitter)
+
+TunnelingAgent.prototype.addRequest = function addRequest(req, options) {
+  var self = this
+
+   // Legacy API: addRequest(req, host, port, path)
+  if (typeof options === 'string') {
+    options = {
+      host: options,
+      port: arguments[2],
+      path: arguments[3]
+    };
+  }
+
+  if (self.sockets.length >= this.maxSockets) {
+    // We are over limit so we'll add it to the queue.
+    self.requests.push({host: options.host, port: options.port, request: req})
+    return
+  }
+
+  // If we are under maxSockets create a new one.
+  self.createConnection({host: options.host, port: options.port, request: req})
+}
+
+TunnelingAgent.prototype.createConnection = function createConnection(pending) {
+  var self = this
+
+  self.createSocket(pending, function(socket) {
+    socket.on('free', onFree)
+    socket.on('close', onCloseOrRemove)
+    socket.on('agentRemove', onCloseOrRemove)
+    pending.request.onSocket(socket)
+
+    function onFree() {
+      self.emit('free', socket, pending.host, pending.port)
+    }
+
+    function onCloseOrRemove(err) {
+      self.removeSocket(socket)
+      socket.removeListener('free', onFree)
+      socket.removeListener('close', onCloseOrRemove)
+      socket.removeListener('agentRemove', onCloseOrRemove)
+    }
+  })
+}
+
+TunnelingAgent.prototype.createSocket = function createSocket(options, cb) {
+  var self = this
+  var placeholder = {}
+  self.sockets.push(placeholder)
+
+  var connectOptions = mergeOptions({}, self.proxyOptions,
+    { method: 'CONNECT'
+    , path: options.host + ':' + options.port
+    , agent: false
+    }
+  )
+  if (connectOptions.proxyAuth) {
+    connectOptions.headers = connectOptions.headers || {}
+    connectOptions.headers['Proxy-Authorization'] = 'Basic ' +
+        Buffer.from(connectOptions.proxyAuth).toString('base64')
+  }
+
+  debug('making CONNECT request')
+  var connectReq = self.request(connectOptions)
+  connectReq.useChunkedEncodingByDefault = false // for v0.6
+  connectReq.once('response', onResponse) // for v0.6
+  connectReq.once('upgrade', onUpgrade)   // for v0.6
+  connectReq.once('connect', onConnect)   // for v0.7 or later
+  connectReq.once('error', onError)
+  connectReq.end()
+
+  function onResponse(res) {
+    // Very hacky. This is necessary to avoid http-parser leaks.
+    res.upgrade = true
+  }
+
+  function onUpgrade(res, socket, head) {
+    // Hacky.
+    process.nextTick(function() {
+      onConnect(res, socket, head)
+    })
+  }
+
+  function onConnect(res, socket, head) {
+    connectReq.removeAllListeners()
+    socket.removeAllListeners()
+
+    if (res.statusCode === 200) {
+      assert.equal(head.length, 0)
+      debug('tunneling connection has established')
+      self.sockets[self.sockets.indexOf(placeholder)] = socket
+      cb(socket)
+    } else {
+      debug('tunneling socket could not be established, statusCode=%d', res.statusCode)
+      var error = new Error('tunneling socket could not be established, ' + 'statusCode=' + res.statusCode)
+      error.code = 'ECONNRESET'
+      options.request.emit('error', error)
+      self.removeSocket(placeholder)
+    }
+  }
+
+  function onError(cause) {
+    connectReq.removeAllListeners()
+
+    debug('tunneling socket could not be established, cause=%s\n', cause.message, cause.stack)
+    var error = new Error('tunneling socket could not be established, ' + 'cause=' + cause.message)
+    error.code = 'ECONNRESET'
+    options.request.emit('error', error)
+    self.removeSocket(placeholder)
+  }
+}
+
+TunnelingAgent.prototype.removeSocket = function removeSocket(socket) {
+  var pos = this.sockets.indexOf(socket)
+  if (pos === -1) return
+
+  this.sockets.splice(pos, 1)
+
+  var pending = this.requests.shift()
+  if (pending) {
+    // If we have pending requests and a socket gets closed a new one
+    // needs to be created to take over in the pool for the one that closed.
+    this.createConnection(pending)
+  }
+}
+
+function createSecureSocket(options, cb) {
+  var self = this
+  TunnelingAgent.prototype.createSocket.call(self, options, function(socket) {
+    // 0 is dummy port for v0.6
+    var secureSocket = tls.connect(0, mergeOptions({}, self.options,
+      { servername: options.host
+      , socket: socket
+      }
+    ))
+    self.sockets[self.sockets.indexOf(socket)] = secureSocket
+    cb(secureSocket)
+  })
+}
+
+
+function mergeOptions(target) {
+  for (var i = 1, len = arguments.length; i < len; ++i) {
+    var overrides = arguments[i]
+    if (typeof overrides === 'object') {
+      var keys = Object.keys(overrides)
+      for (var j = 0, keyLen = keys.length; j < keyLen; ++j) {
+        var k = keys[j]
+        if (overrides[k] !== undefined) {
+          target[k] = overrides[k]
+        }
+      }
+    }
+  }
+  return target
+}
+
+
+var debug
+if (process.env.NODE_DEBUG && /\btunnel\b/.test(process.env.NODE_DEBUG)) {
+  debug = function() {
+    var args = Array.prototype.slice.call(arguments)
+    if (typeof args[0] === 'string') {
+      args[0] = 'TUNNEL: ' + args[0]
+    } else {
+      args.unshift('TUNNEL:')
+    }
+    console.error.apply(console, args)
+  }
+} else {
+  debug = function() {}
+}
+exports.debug = debug // for test
diff --git a/server/node_modules/tunnel-agent/package.json b/server/node_modules/tunnel-agent/package.json
new file mode 100644
index 0000000..a271fda
--- /dev/null
+++ b/server/node_modules/tunnel-agent/package.json
@@ -0,0 +1,22 @@
+{
+  "author": "Mikeal Rogers <mikeal.rogers@gmail.com> (http://www.futurealoof.com)",
+  "name": "tunnel-agent",
+  "license": "Apache-2.0",
+  "description": "HTTP proxy tunneling agent. Formerly part of mikeal/request, now a standalone module.",
+  "version": "0.6.0",
+  "repository": {
+    "url": "https://github.com/mikeal/tunnel-agent"
+  },
+  "main": "index.js",
+  "files": [
+    "index.js"
+  ],
+  "dependencies": {
+    "safe-buffer": "^5.0.1"
+  },
+  "devDependencies": {},
+  "optionalDependencies": {},
+  "engines": {
+    "node": "*"
+  }
+}
diff --git a/server/node_modules/type-is/HISTORY.md b/server/node_modules/type-is/HISTORY.md
new file mode 100644
index 0000000..8de21f7
--- /dev/null
+++ b/server/node_modules/type-is/HISTORY.md
@@ -0,0 +1,259 @@
+1.6.18 / 2019-04-26
+===================
+
+  * Fix regression passing request object to `typeis.is`
+
+1.6.17 / 2019-04-25
+===================
+
+  * deps: mime-types@~2.1.24
+    - Add Apple file extensions from IANA
+    - Add extension `.csl` to `application/vnd.citationstyles.style+xml`
+    - Add extension `.es` to `application/ecmascript`
+    - Add extension `.nq` to `application/n-quads`
+    - Add extension `.nt` to `application/n-triples`
+    - Add extension `.owl` to `application/rdf+xml`
+    - Add extensions `.siv` and `.sieve` to `application/sieve`
+    - Add extensions from IANA for `image/*` types
+    - Add extensions from IANA for `model/*` types
+    - Add extensions to HEIC image types
+    - Add new mime types
+    - Add `text/mdx` with extension `.mdx`
+  * perf: prevent internal `throw` on invalid type
+
+1.6.16 / 2018-02-16
+===================
+
+  * deps: mime-types@~2.1.18
+    - Add `application/raml+yaml` with extension `.raml`
+    - Add `application/wasm` with extension `.wasm`
+    - Add `text/shex` with extension `.shex`
+    - Add extensions for JPEG-2000 images
+    - Add extensions from IANA for `message/*` types
+    - Add extension `.mjs` to `application/javascript`
+    - Add extension `.wadl` to `application/vnd.sun.wadl+xml`
+    - Add extension `.gz` to `application/gzip`
+    - Add glTF types and extensions
+    - Add new mime types
+    - Update extensions `.md` and `.markdown` to be `text/markdown`
+    - Update font MIME types
+    - Update `text/hjson` to registered `application/hjson`
+
+1.6.15 / 2017-03-31
+===================
+
+  * deps: mime-types@~2.1.15
+    - Add new mime types
+
+1.6.14 / 2016-11-18
+===================
+
+  * deps: mime-types@~2.1.13
+    - Add new mime types
+
+1.6.13 / 2016-05-18
+===================
+
+  * deps: mime-types@~2.1.11
+    - Add new mime types
+
+1.6.12 / 2016-02-28
+===================
+
+  * deps: mime-types@~2.1.10
+    - Add new mime types
+    - Fix extension of `application/dash+xml`
+    - Update primary extension for `audio/mp4`
+
+1.6.11 / 2016-01-29
+===================
+
+  * deps: mime-types@~2.1.9
+    - Add new mime types
+
+1.6.10 / 2015-12-01
+===================
+
+  * deps: mime-types@~2.1.8
+    - Add new mime types
+
+1.6.9 / 2015-09-27
+==================
+
+  * deps: mime-types@~2.1.7
+    - Add new mime types
+
+1.6.8 / 2015-09-04
+==================
+
+  * deps: mime-types@~2.1.6
+    - Add new mime types
+
+1.6.7 / 2015-08-20
+==================
+
+  * Fix type error when given invalid type to match against
+  * deps: mime-types@~2.1.5
+    - Add new mime types
+
+1.6.6 / 2015-07-31
+==================
+
+  * deps: mime-types@~2.1.4
+    - Add new mime types
+
+1.6.5 / 2015-07-16
+==================
+
+  * deps: mime-types@~2.1.3
+    - Add new mime types
+
+1.6.4 / 2015-07-01
+==================
+
+  * deps: mime-types@~2.1.2
+    - Add new mime types
+  * perf: enable strict mode
+  * perf: remove argument reassignment
+
+1.6.3 / 2015-06-08
+==================
+
+  * deps: mime-types@~2.1.1
+    - Add new mime types
+  * perf: reduce try block size
+  * perf: remove bitwise operations
+
+1.6.2 / 2015-05-10
+==================
+
+  * deps: mime-types@~2.0.11
+    - Add new mime types
+
+1.6.1 / 2015-03-13
+==================
+
+  * deps: mime-types@~2.0.10
+    - Add new mime types
+
+1.6.0 / 2015-02-12
+==================
+
+  * fix false-positives in `hasBody` `Transfer-Encoding` check
+  * support wildcard for both type and subtype (`*/*`)
+
+1.5.7 / 2015-02-09
+==================
+
+  * fix argument reassignment
+  * deps: mime-types@~2.0.9
+    - Add new mime types
+
+1.5.6 / 2015-01-29
+==================
+
+  * deps: mime-types@~2.0.8
+    - Add new mime types
+
+1.5.5 / 2014-12-30
+==================
+
+  * deps: mime-types@~2.0.7
+    - Add new mime types
+    - Fix missing extensions
+    - Fix various invalid MIME type entries
+    - Remove example template MIME types
+    - deps: mime-db@~1.5.0
+
+1.5.4 / 2014-12-10
+==================
+
+  * deps: mime-types@~2.0.4
+    - Add new mime types
+    - deps: mime-db@~1.3.0
+
+1.5.3 / 2014-11-09
+==================
+
+  * deps: mime-types@~2.0.3
+    - Add new mime types
+    - deps: mime-db@~1.2.0
+
+1.5.2 / 2014-09-28
+==================
+
+  * deps: mime-types@~2.0.2
+    - Add new mime types
+    - deps: mime-db@~1.1.0
+
+1.5.1 / 2014-09-07
+==================
+
+  * Support Node.js 0.6
+  * deps: media-typer@0.3.0
+  * deps: mime-types@~2.0.1
+    - Support Node.js 0.6
+
+1.5.0 / 2014-09-05
+==================
+
+ * fix `hasbody` to be true for `content-length: 0`
+
+1.4.0 / 2014-09-02
+==================
+
+ * update mime-types
+
+1.3.2 / 2014-06-24
+==================
+
+ * use `~` range on mime-types
+
+1.3.1 / 2014-06-19
+==================
+
+ * fix global variable leak
+
+1.3.0 / 2014-06-19
+==================
+
+ * improve type parsing
+
+   - invalid media type never matches
+   - media type not case-sensitive
+   - extra LWS does not affect results
+
+1.2.2 / 2014-06-19
+==================
+
+ * fix behavior on unknown type argument
+
+1.2.1 / 2014-06-03
+==================
+
+ * switch dependency from `mime` to `mime-types@1.0.0`
+
+1.2.0 / 2014-05-11
+==================
+
+ * support suffix matching:
+
+   - `+json` matches `application/vnd+json`
+   - `*/vnd+json` matches `application/vnd+json`
+   - `application/*+json` matches `application/vnd+json`
+
+1.1.0 / 2014-04-12
+==================
+
+ * add non-array values support
+ * expose internal utilities:
+
+   - `.is()`
+   - `.hasBody()`
+   - `.normalize()`
+   - `.match()`
+
+1.0.1 / 2014-03-30
+==================
+
+ * add `multipart` as a shorthand
diff --git a/server/node_modules/type-is/LICENSE b/server/node_modules/type-is/LICENSE
new file mode 100644
index 0000000..386b7b6
--- /dev/null
+++ b/server/node_modules/type-is/LICENSE
@@ -0,0 +1,23 @@
+(The MIT License)
+
+Copyright (c) 2014 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2014-2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/type-is/README.md b/server/node_modules/type-is/README.md
new file mode 100644
index 0000000..b85ef8f
--- /dev/null
+++ b/server/node_modules/type-is/README.md
@@ -0,0 +1,170 @@
+# type-is
+
+[![NPM Version][npm-version-image]][npm-url]
+[![NPM Downloads][npm-downloads-image]][npm-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Infer the content-type of a request.
+
+### Install
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):
+
+```sh
+$ npm install type-is
+```
+
+## API
+
+```js
+var http = require('http')
+var typeis = require('type-is')
+
+http.createServer(function (req, res) {
+  var istext = typeis(req, ['text/*'])
+  res.end('you ' + (istext ? 'sent' : 'did not send') + ' me text')
+})
+```
+
+### typeis(request, types)
+
+Checks if the `request` is one of the `types`. If the request has no body,
+even if there is a `Content-Type` header, then `null` is returned. If the
+`Content-Type` header is invalid or does not matches any of the `types`, then
+`false` is returned. Otherwise, a string of the type that matched is returned.
+
+The `request` argument is expected to be a Node.js HTTP request. The `types`
+argument is an array of type strings.
+
+Each type in the `types` array can be one of the following:
+
+- A file extension name such as `json`. This name will be returned if matched.
+- A mime type such as `application/json`.
+- A mime type with a wildcard such as `*/*` or `*/json` or `application/*`.
+  The full mime type will be returned if matched.
+- A suffix such as `+json`. This can be combined with a wildcard such as
+  `*/vnd+json` or `application/*+json`. The full mime type will be returned
+  if matched.
+
+Some examples to illustrate the inputs and returned value:
+
+
+
+```js
+// req.headers.content-type = 'application/json'
+
+typeis(req, ['json']) // => 'json'
+typeis(req, ['html', 'json']) // => 'json'
+typeis(req, ['application/*']) // => 'application/json'
+typeis(req, ['application/json']) // => 'application/json'
+
+typeis(req, ['html']) // => false
+```
+
+### typeis.hasBody(request)
+
+Returns a Boolean if the given `request` has a body, regardless of the
+`Content-Type` header.
+
+Having a body has no relation to how large the body is (it may be 0 bytes).
+This is similar to how file existence works. If a body does exist, then this
+indicates that there is data to read from the Node.js request stream.
+
+
+
+```js
+if (typeis.hasBody(req)) {
+  // read the body, since there is one
+
+  req.on('data', function (chunk) {
+    // ...
+  })
+}
+```
+
+### typeis.is(mediaType, types)
+
+Checks if the `mediaType` is one of the `types`. If the `mediaType` is invalid
+or does not matches any of the `types`, then `false` is returned. Otherwise, a
+string of the type that matched is returned.
+
+The `mediaType` argument is expected to be a
+[media type](https://tools.ietf.org/html/rfc6838) string. The `types` argument
+is an array of type strings.
+
+Each type in the `types` array can be one of the following:
+
+- A file extension name such as `json`. This name will be returned if matched.
+- A mime type such as `application/json`.
+- A mime type with a wildcard such as `*/*` or `*/json` or `application/*`.
+  The full mime type will be returned if matched.
+- A suffix such as `+json`. This can be combined with a wildcard such as
+  `*/vnd+json` or `application/*+json`. The full mime type will be returned
+  if matched.
+
+Some examples to illustrate the inputs and returned value:
+
+
+
+```js
+var mediaType = 'application/json'
+
+typeis.is(mediaType, ['json']) // => 'json'
+typeis.is(mediaType, ['html', 'json']) // => 'json'
+typeis.is(mediaType, ['application/*']) // => 'application/json'
+typeis.is(mediaType, ['application/json']) // => 'application/json'
+
+typeis.is(mediaType, ['html']) // => false
+```
+
+## Examples
+
+### Example body parser
+
+```js
+var express = require('express')
+var typeis = require('type-is')
+
+var app = express()
+
+app.use(function bodyParser (req, res, next) {
+  if (!typeis.hasBody(req)) {
+    return next()
+  }
+
+  switch (typeis(req, ['urlencoded', 'json', 'multipart'])) {
+    case 'urlencoded':
+      // parse urlencoded body
+      throw new Error('implement urlencoded body parsing')
+    case 'json':
+      // parse json body
+      throw new Error('implement json body parsing')
+    case 'multipart':
+      // parse multipart body
+      throw new Error('implement multipart body parsing')
+    default:
+      // 415 error code
+      res.statusCode = 415
+      res.end()
+      break
+  }
+})
+```
+
+## License
+
+[MIT](LICENSE)
+
+[coveralls-image]: https://badgen.net/coveralls/c/github/jshttp/type-is/master
+[coveralls-url]: https://coveralls.io/r/jshttp/type-is?branch=master
+[node-version-image]: https://badgen.net/npm/node/type-is
+[node-version-url]: https://nodejs.org/en/download
+[npm-downloads-image]: https://badgen.net/npm/dm/type-is
+[npm-url]: https://npmjs.org/package/type-is
+[npm-version-image]: https://badgen.net/npm/v/type-is
+[travis-image]: https://badgen.net/travis/jshttp/type-is/master
+[travis-url]: https://travis-ci.org/jshttp/type-is
diff --git a/server/node_modules/type-is/index.js b/server/node_modules/type-is/index.js
new file mode 100644
index 0000000..890ad76
--- /dev/null
+++ b/server/node_modules/type-is/index.js
@@ -0,0 +1,266 @@
+/*!
+ * type-is
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var typer = require('media-typer')
+var mime = require('mime-types')
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = typeofrequest
+module.exports.is = typeis
+module.exports.hasBody = hasbody
+module.exports.normalize = normalize
+module.exports.match = mimeMatch
+
+/**
+ * Compare a `value` content-type with `types`.
+ * Each `type` can be an extension like `html`,
+ * a special shortcut like `multipart` or `urlencoded`,
+ * or a mime type.
+ *
+ * If no types match, `false` is returned.
+ * Otherwise, the first `type` that matches is returned.
+ *
+ * @param {String} value
+ * @param {Array} types
+ * @public
+ */
+
+function typeis (value, types_) {
+  var i
+  var types = types_
+
+  // remove parameters and normalize
+  var val = tryNormalizeType(value)
+
+  // no type or invalid
+  if (!val) {
+    return false
+  }
+
+  // support flattened arguments
+  if (types && !Array.isArray(types)) {
+    types = new Array(arguments.length - 1)
+    for (i = 0; i < types.length; i++) {
+      types[i] = arguments[i + 1]
+    }
+  }
+
+  // no types, return the content type
+  if (!types || !types.length) {
+    return val
+  }
+
+  var type
+  for (i = 0; i < types.length; i++) {
+    if (mimeMatch(normalize(type = types[i]), val)) {
+      return type[0] === '+' || type.indexOf('*') !== -1
+        ? val
+        : type
+    }
+  }
+
+  // no matches
+  return false
+}
+
+/**
+ * Check if a request has a request body.
+ * A request with a body __must__ either have `transfer-encoding`
+ * or `content-length` headers set.
+ * http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.3
+ *
+ * @param {Object} request
+ * @return {Boolean}
+ * @public
+ */
+
+function hasbody (req) {
+  return req.headers['transfer-encoding'] !== undefined ||
+    !isNaN(req.headers['content-length'])
+}
+
+/**
+ * Check if the incoming request contains the "Content-Type"
+ * header field, and it contains any of the give mime `type`s.
+ * If there is no request body, `null` is returned.
+ * If there is no content type, `false` is returned.
+ * Otherwise, it returns the first `type` that matches.
+ *
+ * Examples:
+ *
+ *     // With Content-Type: text/html; charset=utf-8
+ *     this.is('html'); // => 'html'
+ *     this.is('text/html'); // => 'text/html'
+ *     this.is('text/*', 'application/json'); // => 'text/html'
+ *
+ *     // When Content-Type is application/json
+ *     this.is('json', 'urlencoded'); // => 'json'
+ *     this.is('application/json'); // => 'application/json'
+ *     this.is('html', 'application/*'); // => 'application/json'
+ *
+ *     this.is('html'); // => false
+ *
+ * @param {String|Array} types...
+ * @return {String|false|null}
+ * @public
+ */
+
+function typeofrequest (req, types_) {
+  var types = types_
+
+  // no body
+  if (!hasbody(req)) {
+    return null
+  }
+
+  // support flattened arguments
+  if (arguments.length > 2) {
+    types = new Array(arguments.length - 1)
+    for (var i = 0; i < types.length; i++) {
+      types[i] = arguments[i + 1]
+    }
+  }
+
+  // request content type
+  var value = req.headers['content-type']
+
+  return typeis(value, types)
+}
+
+/**
+ * Normalize a mime type.
+ * If it's a shorthand, expand it to a valid mime type.
+ *
+ * In general, you probably want:
+ *
+ *   var type = is(req, ['urlencoded', 'json', 'multipart']);
+ *
+ * Then use the appropriate body parsers.
+ * These three are the most common request body types
+ * and are thus ensured to work.
+ *
+ * @param {String} type
+ * @private
+ */
+
+function normalize (type) {
+  if (typeof type !== 'string') {
+    // invalid type
+    return false
+  }
+
+  switch (type) {
+    case 'urlencoded':
+      return 'application/x-www-form-urlencoded'
+    case 'multipart':
+      return 'multipart/*'
+  }
+
+  if (type[0] === '+') {
+    // "+json" -> "*/*+json" expando
+    return '*/*' + type
+  }
+
+  return type.indexOf('/') === -1
+    ? mime.lookup(type)
+    : type
+}
+
+/**
+ * Check if `expected` mime type
+ * matches `actual` mime type with
+ * wildcard and +suffix support.
+ *
+ * @param {String} expected
+ * @param {String} actual
+ * @return {Boolean}
+ * @private
+ */
+
+function mimeMatch (expected, actual) {
+  // invalid type
+  if (expected === false) {
+    return false
+  }
+
+  // split types
+  var actualParts = actual.split('/')
+  var expectedParts = expected.split('/')
+
+  // invalid format
+  if (actualParts.length !== 2 || expectedParts.length !== 2) {
+    return false
+  }
+
+  // validate type
+  if (expectedParts[0] !== '*' && expectedParts[0] !== actualParts[0]) {
+    return false
+  }
+
+  // validate suffix wildcard
+  if (expectedParts[1].substr(0, 2) === '*+') {
+    return expectedParts[1].length <= actualParts[1].length + 1 &&
+      expectedParts[1].substr(1) === actualParts[1].substr(1 - expectedParts[1].length)
+  }
+
+  // validate subtype
+  if (expectedParts[1] !== '*' && expectedParts[1] !== actualParts[1]) {
+    return false
+  }
+
+  return true
+}
+
+/**
+ * Normalize a type and remove parameters.
+ *
+ * @param {string} value
+ * @return {string}
+ * @private
+ */
+
+function normalizeType (value) {
+  // parse the type
+  var type = typer.parse(value)
+
+  // remove the parameters
+  type.parameters = undefined
+
+  // reformat it
+  return typer.format(type)
+}
+
+/**
+ * Try to normalize a type and remove parameters.
+ *
+ * @param {string} value
+ * @return {string}
+ * @private
+ */
+
+function tryNormalizeType (value) {
+  if (!value) {
+    return null
+  }
+
+  try {
+    return normalizeType(value)
+  } catch (err) {
+    return null
+  }
+}
diff --git a/server/node_modules/type-is/package.json b/server/node_modules/type-is/package.json
new file mode 100644
index 0000000..97ba5f1
--- /dev/null
+++ b/server/node_modules/type-is/package.json
@@ -0,0 +1,45 @@
+{
+  "name": "type-is",
+  "description": "Infer the content-type of a request.",
+  "version": "1.6.18",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "license": "MIT",
+  "repository": "jshttp/type-is",
+  "dependencies": {
+    "media-typer": "0.3.0",
+    "mime-types": "~2.1.24"
+  },
+  "devDependencies": {
+    "eslint": "5.16.0",
+    "eslint-config-standard": "12.0.0",
+    "eslint-plugin-import": "2.17.2",
+    "eslint-plugin-markdown": "1.0.0",
+    "eslint-plugin-node": "8.0.1",
+    "eslint-plugin-promise": "4.1.1",
+    "eslint-plugin-standard": "4.0.0",
+    "mocha": "6.1.4",
+    "nyc": "14.0.0"
+  },
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "index.js"
+  ],
+  "scripts": {
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec --check-leaks --bail test/",
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "test-travis": "nyc --reporter=text npm test"
+  },
+  "keywords": [
+    "content",
+    "type",
+    "checking"
+  ]
+}
diff --git a/server/node_modules/typedarray/.travis.yml b/server/node_modules/typedarray/.travis.yml
new file mode 100644
index 0000000..cc4dba2
--- /dev/null
+++ b/server/node_modules/typedarray/.travis.yml
@@ -0,0 +1,4 @@
+language: node_js
+node_js:
+  - "0.8"
+  - "0.10"
diff --git a/server/node_modules/typedarray/LICENSE b/server/node_modules/typedarray/LICENSE
new file mode 100644
index 0000000..11adfae
--- /dev/null
+++ b/server/node_modules/typedarray/LICENSE
@@ -0,0 +1,35 @@
+/*
+ Copyright (c) 2010, Linden Research, Inc.
+ Copyright (c) 2012, Joshua Bell
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ THE SOFTWARE.
+ $/LicenseInfo$
+ */
+
+// Original can be found at:
+//   https://bitbucket.org/lindenlab/llsd
+// Modifications by Joshua Bell inexorabletash@gmail.com
+//   https://github.com/inexorabletash/polyfill
+
+// ES3/ES5 implementation of the Krhonos Typed Array Specification
+//   Ref: http://www.khronos.org/registry/typedarray/specs/latest/
+//   Date: 2011-02-01
+//
+// Variations:
+//  * Allows typed_array.get/set() as alias for subscripts (typed_array[])
diff --git a/server/node_modules/typedarray/example/tarray.js b/server/node_modules/typedarray/example/tarray.js
new file mode 100644
index 0000000..8423d7c
--- /dev/null
+++ b/server/node_modules/typedarray/example/tarray.js
@@ -0,0 +1,4 @@
+var Uint8Array = require('../').Uint8Array;
+var ua = new Uint8Array(5);
+ua[1] = 256 + 55;
+console.log(ua[1]);
diff --git a/server/node_modules/typedarray/index.js b/server/node_modules/typedarray/index.js
new file mode 100644
index 0000000..5e54084
--- /dev/null
+++ b/server/node_modules/typedarray/index.js
@@ -0,0 +1,630 @@
+var undefined = (void 0); // Paranoia
+
+// Beyond this value, index getters/setters (i.e. array[0], array[1]) are so slow to
+// create, and consume so much memory, that the browser appears frozen.
+var MAX_ARRAY_LENGTH = 1e5;
+
+// Approximations of internal ECMAScript conversion functions
+var ECMAScript = (function() {
+  // Stash a copy in case other scripts modify these
+  var opts = Object.prototype.toString,
+      ophop = Object.prototype.hasOwnProperty;
+
+  return {
+    // Class returns internal [[Class]] property, used to avoid cross-frame instanceof issues:
+    Class: function(v) { return opts.call(v).replace(/^\[object *|\]$/g, ''); },
+    HasProperty: function(o, p) { return p in o; },
+    HasOwnProperty: function(o, p) { return ophop.call(o, p); },
+    IsCallable: function(o) { return typeof o === 'function'; },
+    ToInt32: function(v) { return v >> 0; },
+    ToUint32: function(v) { return v >>> 0; }
+  };
+}());
+
+// Snapshot intrinsics
+var LN2 = Math.LN2,
+    abs = Math.abs,
+    floor = Math.floor,
+    log = Math.log,
+    min = Math.min,
+    pow = Math.pow,
+    round = Math.round;
+
+// ES5: lock down object properties
+function configureProperties(obj) {
+  if (getOwnPropNames && defineProp) {
+    var props = getOwnPropNames(obj), i;
+    for (i = 0; i < props.length; i += 1) {
+      defineProp(obj, props[i], {
+        value: obj[props[i]],
+        writable: false,
+        enumerable: false,
+        configurable: false
+      });
+    }
+  }
+}
+
+// emulate ES5 getter/setter API using legacy APIs
+// http://blogs.msdn.com/b/ie/archive/2010/09/07/transitioning-existing-code-to-the-es5-getter-setter-apis.aspx
+// (second clause tests for Object.defineProperty() in IE<9 that only supports extending DOM prototypes, but
+// note that IE<9 does not support __defineGetter__ or __defineSetter__ so it just renders the method harmless)
+var defineProp
+if (Object.defineProperty && (function() {
+      try {
+        Object.defineProperty({}, 'x', {});
+        return true;
+      } catch (e) {
+        return false;
+      }
+    })()) {
+  defineProp = Object.defineProperty;
+} else {
+  defineProp = function(o, p, desc) {
+    if (!o === Object(o)) throw new TypeError("Object.defineProperty called on non-object");
+    if (ECMAScript.HasProperty(desc, 'get') && Object.prototype.__defineGetter__) { Object.prototype.__defineGetter__.call(o, p, desc.get); }
+    if (ECMAScript.HasProperty(desc, 'set') && Object.prototype.__defineSetter__) { Object.prototype.__defineSetter__.call(o, p, desc.set); }
+    if (ECMAScript.HasProperty(desc, 'value')) { o[p] = desc.value; }
+    return o;
+  };
+}
+
+var getOwnPropNames = Object.getOwnPropertyNames || function (o) {
+  if (o !== Object(o)) throw new TypeError("Object.getOwnPropertyNames called on non-object");
+  var props = [], p;
+  for (p in o) {
+    if (ECMAScript.HasOwnProperty(o, p)) {
+      props.push(p);
+    }
+  }
+  return props;
+};
+
+// ES5: Make obj[index] an alias for obj._getter(index)/obj._setter(index, value)
+// for index in 0 ... obj.length
+function makeArrayAccessors(obj) {
+  if (!defineProp) { return; }
+
+  if (obj.length > MAX_ARRAY_LENGTH) throw new RangeError("Array too large for polyfill");
+
+  function makeArrayAccessor(index) {
+    defineProp(obj, index, {
+      'get': function() { return obj._getter(index); },
+      'set': function(v) { obj._setter(index, v); },
+      enumerable: true,
+      configurable: false
+    });
+  }
+
+  var i;
+  for (i = 0; i < obj.length; i += 1) {
+    makeArrayAccessor(i);
+  }
+}
+
+// Internal conversion functions:
+//    pack<Type>()   - take a number (interpreted as Type), output a byte array
+//    unpack<Type>() - take a byte array, output a Type-like number
+
+function as_signed(value, bits) { var s = 32 - bits; return (value << s) >> s; }
+function as_unsigned(value, bits) { var s = 32 - bits; return (value << s) >>> s; }
+
+function packI8(n) { return [n & 0xff]; }
+function unpackI8(bytes) { return as_signed(bytes[0], 8); }
+
+function packU8(n) { return [n & 0xff]; }
+function unpackU8(bytes) { return as_unsigned(bytes[0], 8); }
+
+function packU8Clamped(n) { n = round(Number(n)); return [n < 0 ? 0 : n > 0xff ? 0xff : n & 0xff]; }
+
+function packI16(n) { return [(n >> 8) & 0xff, n & 0xff]; }
+function unpackI16(bytes) { return as_signed(bytes[0] << 8 | bytes[1], 16); }
+
+function packU16(n) { return [(n >> 8) & 0xff, n & 0xff]; }
+function unpackU16(bytes) { return as_unsigned(bytes[0] << 8 | bytes[1], 16); }
+
+function packI32(n) { return [(n >> 24) & 0xff, (n >> 16) & 0xff, (n >> 8) & 0xff, n & 0xff]; }
+function unpackI32(bytes) { return as_signed(bytes[0] << 24 | bytes[1] << 16 | bytes[2] << 8 | bytes[3], 32); }
+
+function packU32(n) { return [(n >> 24) & 0xff, (n >> 16) & 0xff, (n >> 8) & 0xff, n & 0xff]; }
+function unpackU32(bytes) { return as_unsigned(bytes[0] << 24 | bytes[1] << 16 | bytes[2] << 8 | bytes[3], 32); }
+
+function packIEEE754(v, ebits, fbits) {
+
+  var bias = (1 << (ebits - 1)) - 1,
+      s, e, f, ln,
+      i, bits, str, bytes;
+
+  function roundToEven(n) {
+    var w = floor(n), f = n - w;
+    if (f < 0.5)
+      return w;
+    if (f > 0.5)
+      return w + 1;
+    return w % 2 ? w + 1 : w;
+  }
+
+  // Compute sign, exponent, fraction
+  if (v !== v) {
+    // NaN
+    // http://dev.w3.org/2006/webapi/WebIDL/#es-type-mapping
+    e = (1 << ebits) - 1; f = pow(2, fbits - 1); s = 0;
+  } else if (v === Infinity || v === -Infinity) {
+    e = (1 << ebits) - 1; f = 0; s = (v < 0) ? 1 : 0;
+  } else if (v === 0) {
+    e = 0; f = 0; s = (1 / v === -Infinity) ? 1 : 0;
+  } else {
+    s = v < 0;
+    v = abs(v);
+
+    if (v >= pow(2, 1 - bias)) {
+      e = min(floor(log(v) / LN2), 1023);
+      f = roundToEven(v / pow(2, e) * pow(2, fbits));
+      if (f / pow(2, fbits) >= 2) {
+        e = e + 1;
+        f = 1;
+      }
+      if (e > bias) {
+        // Overflow
+        e = (1 << ebits) - 1;
+        f = 0;
+      } else {
+        // Normalized
+        e = e + bias;
+        f = f - pow(2, fbits);
+      }
+    } else {
+      // Denormalized
+      e = 0;
+      f = roundToEven(v / pow(2, 1 - bias - fbits));
+    }
+  }
+
+  // Pack sign, exponent, fraction
+  bits = [];
+  for (i = fbits; i; i -= 1) { bits.push(f % 2 ? 1 : 0); f = floor(f / 2); }
+  for (i = ebits; i; i -= 1) { bits.push(e % 2 ? 1 : 0); e = floor(e / 2); }
+  bits.push(s ? 1 : 0);
+  bits.reverse();
+  str = bits.join('');
+
+  // Bits to bytes
+  bytes = [];
+  while (str.length) {
+    bytes.push(parseInt(str.substring(0, 8), 2));
+    str = str.substring(8);
+  }
+  return bytes;
+}
+
+function unpackIEEE754(bytes, ebits, fbits) {
+
+  // Bytes to bits
+  var bits = [], i, j, b, str,
+      bias, s, e, f;
+
+  for (i = bytes.length; i; i -= 1) {
+    b = bytes[i - 1];
+    for (j = 8; j; j -= 1) {
+      bits.push(b % 2 ? 1 : 0); b = b >> 1;
+    }
+  }
+  bits.reverse();
+  str = bits.join('');
+
+  // Unpack sign, exponent, fraction
+  bias = (1 << (ebits - 1)) - 1;
+  s = parseInt(str.substring(0, 1), 2) ? -1 : 1;
+  e = parseInt(str.substring(1, 1 + ebits), 2);
+  f = parseInt(str.substring(1 + ebits), 2);
+
+  // Produce number
+  if (e === (1 << ebits) - 1) {
+    return f !== 0 ? NaN : s * Infinity;
+  } else if (e > 0) {
+    // Normalized
+    return s * pow(2, e - bias) * (1 + f / pow(2, fbits));
+  } else if (f !== 0) {
+    // Denormalized
+    return s * pow(2, -(bias - 1)) * (f / pow(2, fbits));
+  } else {
+    return s < 0 ? -0 : 0;
+  }
+}
+
+function unpackF64(b) { return unpackIEEE754(b, 11, 52); }
+function packF64(v) { return packIEEE754(v, 11, 52); }
+function unpackF32(b) { return unpackIEEE754(b, 8, 23); }
+function packF32(v) { return packIEEE754(v, 8, 23); }
+
+
+//
+// 3 The ArrayBuffer Type
+//
+
+(function() {
+
+  /** @constructor */
+  var ArrayBuffer = function ArrayBuffer(length) {
+    length = ECMAScript.ToInt32(length);
+    if (length < 0) throw new RangeError('ArrayBuffer size is not a small enough positive integer');
+
+    this.byteLength = length;
+    this._bytes = [];
+    this._bytes.length = length;
+
+    var i;
+    for (i = 0; i < this.byteLength; i += 1) {
+      this._bytes[i] = 0;
+    }
+
+    configureProperties(this);
+  };
+
+  exports.ArrayBuffer = exports.ArrayBuffer || ArrayBuffer;
+
+  //
+  // 4 The ArrayBufferView Type
+  //
+
+  // NOTE: this constructor is not exported
+  /** @constructor */
+  var ArrayBufferView = function ArrayBufferView() {
+    //this.buffer = null;
+    //this.byteOffset = 0;
+    //this.byteLength = 0;
+  };
+
+  //
+  // 5 The Typed Array View Types
+  //
+
+  function makeConstructor(bytesPerElement, pack, unpack) {
+    // Each TypedArray type requires a distinct constructor instance with
+    // identical logic, which this produces.
+
+    var ctor;
+    ctor = function(buffer, byteOffset, length) {
+      var array, sequence, i, s;
+
+      if (!arguments.length || typeof arguments[0] === 'number') {
+        // Constructor(unsigned long length)
+        this.length = ECMAScript.ToInt32(arguments[0]);
+        if (length < 0) throw new RangeError('ArrayBufferView size is not a small enough positive integer');
+
+        this.byteLength = this.length * this.BYTES_PER_ELEMENT;
+        this.buffer = new ArrayBuffer(this.byteLength);
+        this.byteOffset = 0;
+      } else if (typeof arguments[0] === 'object' && arguments[0].constructor === ctor) {
+        // Constructor(TypedArray array)
+        array = arguments[0];
+
+        this.length = array.length;
+        this.byteLength = this.length * this.BYTES_PER_ELEMENT;
+        this.buffer = new ArrayBuffer(this.byteLength);
+        this.byteOffset = 0;
+
+        for (i = 0; i < this.length; i += 1) {
+          this._setter(i, array._getter(i));
+        }
+      } else if (typeof arguments[0] === 'object' &&
+                 !(arguments[0] instanceof ArrayBuffer || ECMAScript.Class(arguments[0]) === 'ArrayBuffer')) {
+        // Constructor(sequence<type> array)
+        sequence = arguments[0];
+
+        this.length = ECMAScript.ToUint32(sequence.length);
+        this.byteLength = this.length * this.BYTES_PER_ELEMENT;
+        this.buffer = new ArrayBuffer(this.byteLength);
+        this.byteOffset = 0;
+
+        for (i = 0; i < this.length; i += 1) {
+          s = sequence[i];
+          this._setter(i, Number(s));
+        }
+      } else if (typeof arguments[0] === 'object' &&
+                 (arguments[0] instanceof ArrayBuffer || ECMAScript.Class(arguments[0]) === 'ArrayBuffer')) {
+        // Constructor(ArrayBuffer buffer,
+        //             optional unsigned long byteOffset, optional unsigned long length)
+        this.buffer = buffer;
+
+        this.byteOffset = ECMAScript.ToUint32(byteOffset);
+        if (this.byteOffset > this.buffer.byteLength) {
+          throw new RangeError("byteOffset out of range");
+        }
+
+        if (this.byteOffset % this.BYTES_PER_ELEMENT) {
+          // The given byteOffset must be a multiple of the element
+          // size of the specific type, otherwise an exception is raised.
+          throw new RangeError("ArrayBuffer length minus the byteOffset is not a multiple of the element size.");
+        }
+
+        if (arguments.length < 3) {
+          this.byteLength = this.buffer.byteLength - this.byteOffset;
+
+          if (this.byteLength % this.BYTES_PER_ELEMENT) {
+            throw new RangeError("length of buffer minus byteOffset not a multiple of the element size");
+          }
+          this.length = this.byteLength / this.BYTES_PER_ELEMENT;
+        } else {
+          this.length = ECMAScript.ToUint32(length);
+          this.byteLength = this.length * this.BYTES_PER_ELEMENT;
+        }
+
+        if ((this.byteOffset + this.byteLength) > this.buffer.byteLength) {
+          throw new RangeError("byteOffset and length reference an area beyond the end of the buffer");
+        }
+      } else {
+        throw new TypeError("Unexpected argument type(s)");
+      }
+
+      this.constructor = ctor;
+
+      configureProperties(this);
+      makeArrayAccessors(this);
+    };
+
+    ctor.prototype = new ArrayBufferView();
+    ctor.prototype.BYTES_PER_ELEMENT = bytesPerElement;
+    ctor.prototype._pack = pack;
+    ctor.prototype._unpack = unpack;
+    ctor.BYTES_PER_ELEMENT = bytesPerElement;
+
+    // getter type (unsigned long index);
+    ctor.prototype._getter = function(index) {
+      if (arguments.length < 1) throw new SyntaxError("Not enough arguments");
+
+      index = ECMAScript.ToUint32(index);
+      if (index >= this.length) {
+        return undefined;
+      }
+
+      var bytes = [], i, o;
+      for (i = 0, o = this.byteOffset + index * this.BYTES_PER_ELEMENT;
+           i < this.BYTES_PER_ELEMENT;
+           i += 1, o += 1) {
+        bytes.push(this.buffer._bytes[o]);
+      }
+      return this._unpack(bytes);
+    };
+
+    // NONSTANDARD: convenience alias for getter: type get(unsigned long index);
+    ctor.prototype.get = ctor.prototype._getter;
+
+    // setter void (unsigned long index, type value);
+    ctor.prototype._setter = function(index, value) {
+      if (arguments.length < 2) throw new SyntaxError("Not enough arguments");
+
+      index = ECMAScript.ToUint32(index);
+      if (index >= this.length) {
+        return undefined;
+      }
+
+      var bytes = this._pack(value), i, o;
+      for (i = 0, o = this.byteOffset + index * this.BYTES_PER_ELEMENT;
+           i < this.BYTES_PER_ELEMENT;
+           i += 1, o += 1) {
+        this.buffer._bytes[o] = bytes[i];
+      }
+    };
+
+    // void set(TypedArray array, optional unsigned long offset);
+    // void set(sequence<type> array, optional unsigned long offset);
+    ctor.prototype.set = function(index, value) {
+      if (arguments.length < 1) throw new SyntaxError("Not enough arguments");
+      var array, sequence, offset, len,
+          i, s, d,
+          byteOffset, byteLength, tmp;
+
+      if (typeof arguments[0] === 'object' && arguments[0].constructor === this.constructor) {
+        // void set(TypedArray array, optional unsigned long offset);
+        array = arguments[0];
+        offset = ECMAScript.ToUint32(arguments[1]);
+
+        if (offset + array.length > this.length) {
+          throw new RangeError("Offset plus length of array is out of range");
+        }
+
+        byteOffset = this.byteOffset + offset * this.BYTES_PER_ELEMENT;
+        byteLength = array.length * this.BYTES_PER_ELEMENT;
+
+        if (array.buffer === this.buffer) {
+          tmp = [];
+          for (i = 0, s = array.byteOffset; i < byteLength; i += 1, s += 1) {
+            tmp[i] = array.buffer._bytes[s];
+          }
+          for (i = 0, d = byteOffset; i < byteLength; i += 1, d += 1) {
+            this.buffer._bytes[d] = tmp[i];
+          }
+        } else {
+          for (i = 0, s = array.byteOffset, d = byteOffset;
+               i < byteLength; i += 1, s += 1, d += 1) {
+            this.buffer._bytes[d] = array.buffer._bytes[s];
+          }
+        }
+      } else if (typeof arguments[0] === 'object' && typeof arguments[0].length !== 'undefined') {
+        // void set(sequence<type> array, optional unsigned long offset);
+        sequence = arguments[0];
+        len = ECMAScript.ToUint32(sequence.length);
+        offset = ECMAScript.ToUint32(arguments[1]);
+
+        if (offset + len > this.length) {
+          throw new RangeError("Offset plus length of array is out of range");
+        }
+
+        for (i = 0; i < len; i += 1) {
+          s = sequence[i];
+          this._setter(offset + i, Number(s));
+        }
+      } else {
+        throw new TypeError("Unexpected argument type(s)");
+      }
+    };
+
+    // TypedArray subarray(long begin, optional long end);
+    ctor.prototype.subarray = function(start, end) {
+      function clamp(v, min, max) { return v < min ? min : v > max ? max : v; }
+
+      start = ECMAScript.ToInt32(start);
+      end = ECMAScript.ToInt32(end);
+
+      if (arguments.length < 1) { start = 0; }
+      if (arguments.length < 2) { end = this.length; }
+
+      if (start < 0) { start = this.length + start; }
+      if (end < 0) { end = this.length + end; }
+
+      start = clamp(start, 0, this.length);
+      end = clamp(end, 0, this.length);
+
+      var len = end - start;
+      if (len < 0) {
+        len = 0;
+      }
+
+      return new this.constructor(
+        this.buffer, this.byteOffset + start * this.BYTES_PER_ELEMENT, len);
+    };
+
+    return ctor;
+  }
+
+  var Int8Array = makeConstructor(1, packI8, unpackI8);
+  var Uint8Array = makeConstructor(1, packU8, unpackU8);
+  var Uint8ClampedArray = makeConstructor(1, packU8Clamped, unpackU8);
+  var Int16Array = makeConstructor(2, packI16, unpackI16);
+  var Uint16Array = makeConstructor(2, packU16, unpackU16);
+  var Int32Array = makeConstructor(4, packI32, unpackI32);
+  var Uint32Array = makeConstructor(4, packU32, unpackU32);
+  var Float32Array = makeConstructor(4, packF32, unpackF32);
+  var Float64Array = makeConstructor(8, packF64, unpackF64);
+
+  exports.Int8Array = exports.Int8Array || Int8Array;
+  exports.Uint8Array = exports.Uint8Array || Uint8Array;
+  exports.Uint8ClampedArray = exports.Uint8ClampedArray || Uint8ClampedArray;
+  exports.Int16Array = exports.Int16Array || Int16Array;
+  exports.Uint16Array = exports.Uint16Array || Uint16Array;
+  exports.Int32Array = exports.Int32Array || Int32Array;
+  exports.Uint32Array = exports.Uint32Array || Uint32Array;
+  exports.Float32Array = exports.Float32Array || Float32Array;
+  exports.Float64Array = exports.Float64Array || Float64Array;
+}());
+
+//
+// 6 The DataView View Type
+//
+
+(function() {
+  function r(array, index) {
+    return ECMAScript.IsCallable(array.get) ? array.get(index) : array[index];
+  }
+
+  var IS_BIG_ENDIAN = (function() {
+    var u16array = new(exports.Uint16Array)([0x1234]),
+        u8array = new(exports.Uint8Array)(u16array.buffer);
+    return r(u8array, 0) === 0x12;
+  }());
+
+  // Constructor(ArrayBuffer buffer,
+  //             optional unsigned long byteOffset,
+  //             optional unsigned long byteLength)
+  /** @constructor */
+  var DataView = function DataView(buffer, byteOffset, byteLength) {
+    if (arguments.length === 0) {
+      buffer = new exports.ArrayBuffer(0);
+    } else if (!(buffer instanceof exports.ArrayBuffer || ECMAScript.Class(buffer) === 'ArrayBuffer')) {
+      throw new TypeError("TypeError");
+    }
+
+    this.buffer = buffer || new exports.ArrayBuffer(0);
+
+    this.byteOffset = ECMAScript.ToUint32(byteOffset);
+    if (this.byteOffset > this.buffer.byteLength) {
+      throw new RangeError("byteOffset out of range");
+    }
+
+    if (arguments.length < 3) {
+      this.byteLength = this.buffer.byteLength - this.byteOffset;
+    } else {
+      this.byteLength = ECMAScript.ToUint32(byteLength);
+    }
+
+    if ((this.byteOffset + this.byteLength) > this.buffer.byteLength) {
+      throw new RangeError("byteOffset and length reference an area beyond the end of the buffer");
+    }
+
+    configureProperties(this);
+  };
+
+  function makeGetter(arrayType) {
+    return function(byteOffset, littleEndian) {
+
+      byteOffset = ECMAScript.ToUint32(byteOffset);
+
+      if (byteOffset + arrayType.BYTES_PER_ELEMENT > this.byteLength) {
+        throw new RangeError("Array index out of range");
+      }
+      byteOffset += this.byteOffset;
+
+      var uint8Array = new exports.Uint8Array(this.buffer, byteOffset, arrayType.BYTES_PER_ELEMENT),
+          bytes = [], i;
+      for (i = 0; i < arrayType.BYTES_PER_ELEMENT; i += 1) {
+        bytes.push(r(uint8Array, i));
+      }
+
+      if (Boolean(littleEndian) === Boolean(IS_BIG_ENDIAN)) {
+        bytes.reverse();
+      }
+
+      return r(new arrayType(new exports.Uint8Array(bytes).buffer), 0);
+    };
+  }
+
+  DataView.prototype.getUint8 = makeGetter(exports.Uint8Array);
+  DataView.prototype.getInt8 = makeGetter(exports.Int8Array);
+  DataView.prototype.getUint16 = makeGetter(exports.Uint16Array);
+  DataView.prototype.getInt16 = makeGetter(exports.Int16Array);
+  DataView.prototype.getUint32 = makeGetter(exports.Uint32Array);
+  DataView.prototype.getInt32 = makeGetter(exports.Int32Array);
+  DataView.prototype.getFloat32 = makeGetter(exports.Float32Array);
+  DataView.prototype.getFloat64 = makeGetter(exports.Float64Array);
+
+  function makeSetter(arrayType) {
+    return function(byteOffset, value, littleEndian) {
+
+      byteOffset = ECMAScript.ToUint32(byteOffset);
+      if (byteOffset + arrayType.BYTES_PER_ELEMENT > this.byteLength) {
+        throw new RangeError("Array index out of range");
+      }
+
+      // Get bytes
+      var typeArray = new arrayType([value]),
+          byteArray = new exports.Uint8Array(typeArray.buffer),
+          bytes = [], i, byteView;
+
+      for (i = 0; i < arrayType.BYTES_PER_ELEMENT; i += 1) {
+        bytes.push(r(byteArray, i));
+      }
+
+      // Flip if necessary
+      if (Boolean(littleEndian) === Boolean(IS_BIG_ENDIAN)) {
+        bytes.reverse();
+      }
+
+      // Write them
+      byteView = new exports.Uint8Array(this.buffer, byteOffset, arrayType.BYTES_PER_ELEMENT);
+      byteView.set(bytes);
+    };
+  }
+
+  DataView.prototype.setUint8 = makeSetter(exports.Uint8Array);
+  DataView.prototype.setInt8 = makeSetter(exports.Int8Array);
+  DataView.prototype.setUint16 = makeSetter(exports.Uint16Array);
+  DataView.prototype.setInt16 = makeSetter(exports.Int16Array);
+  DataView.prototype.setUint32 = makeSetter(exports.Uint32Array);
+  DataView.prototype.setInt32 = makeSetter(exports.Int32Array);
+  DataView.prototype.setFloat32 = makeSetter(exports.Float32Array);
+  DataView.prototype.setFloat64 = makeSetter(exports.Float64Array);
+
+  exports.DataView = exports.DataView || DataView;
+
+}());
diff --git a/server/node_modules/typedarray/package.json b/server/node_modules/typedarray/package.json
new file mode 100644
index 0000000..a7854a0
--- /dev/null
+++ b/server/node_modules/typedarray/package.json
@@ -0,0 +1,55 @@
+{
+  "name": "typedarray",
+  "version": "0.0.6",
+  "description": "TypedArray polyfill for old browsers",
+  "main": "index.js",
+  "devDependencies": {
+    "tape": "~2.3.2"
+  },
+  "scripts": {
+    "test": "tape test/*.js test/server/*.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/substack/typedarray.git"
+  },
+  "homepage": "https://github.com/substack/typedarray",
+  "keywords": [
+    "ArrayBuffer",
+    "DataView",
+    "Float32Array",
+    "Float64Array",
+    "Int8Array",
+    "Int16Array",
+    "Int32Array",
+    "Uint8Array",
+    "Uint8ClampedArray",
+    "Uint16Array",
+    "Uint32Array",
+    "typed",
+    "array",
+    "polyfill"
+  ],
+  "author": {
+    "name": "James Halliday",
+    "email": "mail@substack.net",
+    "url": "http://substack.net"
+  },
+  "license": "MIT",
+  "testling": {
+    "files": "test/*.js",
+    "browsers": [
+      "ie/6..latest",
+      "firefox/16..latest",
+      "firefox/nightly",
+      "chrome/22..latest",
+      "chrome/canary",
+      "opera/12..latest",
+      "opera/next",
+      "safari/5.1..latest",
+      "ipad/6.0..latest",
+      "iphone/6.0..latest",
+      "android-browser/4.2..latest"
+    ]
+  }
+}
diff --git a/server/node_modules/typedarray/readme.markdown b/server/node_modules/typedarray/readme.markdown
new file mode 100644
index 0000000..d18f6f7
--- /dev/null
+++ b/server/node_modules/typedarray/readme.markdown
@@ -0,0 +1,61 @@
+# typedarray
+
+TypedArray polyfill ripped from [this
+module](https://raw.github.com/inexorabletash/polyfill).
+
+[![build status](https://secure.travis-ci.org/substack/typedarray.png)](http://travis-ci.org/substack/typedarray)
+
+[![testling badge](https://ci.testling.com/substack/typedarray.png)](https://ci.testling.com/substack/typedarray)
+
+# example
+
+``` js
+var Uint8Array = require('typedarray').Uint8Array;
+var ua = new Uint8Array(5);
+ua[1] = 256 + 55;
+console.log(ua[1]);
+```
+
+output:
+
+```
+55
+```
+
+# methods
+
+``` js
+var TA = require('typedarray')
+```
+
+The `TA` object has the following constructors:
+
+* TA.ArrayBuffer
+* TA.DataView
+* TA.Float32Array
+* TA.Float64Array
+* TA.Int8Array
+* TA.Int16Array
+* TA.Int32Array
+* TA.Uint8Array
+* TA.Uint8ClampedArray
+* TA.Uint16Array
+* TA.Uint32Array
+
+# install
+
+With [npm](https://npmjs.org) do:
+
+```
+npm install typedarray
+```
+
+To use this module in the browser, compile with
+[browserify](http://browserify.org)
+or download a UMD build from browserify CDN:
+
+http://wzrd.in/standalone/typedarray@latest
+
+# license
+
+MIT
diff --git a/server/node_modules/typedarray/test/server/undef_globals.js b/server/node_modules/typedarray/test/server/undef_globals.js
new file mode 100644
index 0000000..425950f
--- /dev/null
+++ b/server/node_modules/typedarray/test/server/undef_globals.js
@@ -0,0 +1,19 @@
+var test = require('tape');
+var vm = require('vm');
+var fs = require('fs');
+var src = fs.readFileSync(__dirname + '/../../index.js', 'utf8');
+
+test('u8a without globals', function (t) {
+    var c = {
+        module: { exports: {} },
+    };
+    c.exports = c.module.exports;
+    vm.runInNewContext(src, c);
+    var TA = c.module.exports;
+    var ua = new(TA.Uint8Array)(5);
+    
+    t.equal(ua.length, 5);
+    ua[1] = 256 + 55;
+    t.equal(ua[1], 55);
+    t.end();
+});
diff --git a/server/node_modules/typedarray/test/tarray.js b/server/node_modules/typedarray/test/tarray.js
new file mode 100644
index 0000000..df596a3
--- /dev/null
+++ b/server/node_modules/typedarray/test/tarray.js
@@ -0,0 +1,10 @@
+var TA = require('../');
+var test = require('tape');
+
+test('tiny u8a test', function (t) {
+    var ua = new(TA.Uint8Array)(5);
+    t.equal(ua.length, 5);
+    ua[1] = 256 + 55;
+    t.equal(ua[1], 55);
+    t.end();
+});
diff --git a/server/node_modules/uid-safe/HISTORY.md b/server/node_modules/uid-safe/HISTORY.md
new file mode 100644
index 0000000..3ec249f
--- /dev/null
+++ b/server/node_modules/uid-safe/HISTORY.md
@@ -0,0 +1,61 @@
+2.1.5 / 2017-08-02
+==================
+
+  * perf: remove only trailing `=`
+
+2.1.4 / 2017-03-02
+==================
+
+  * Remove `base64-url` dependency
+
+2.1.3 / 2016-10-30
+==================
+
+  * deps: base64-url@1.3.3
+
+2.1.2 / 2016-08-15
+==================
+
+  * deps: base64-url@1.3.2
+
+2.1.1 / 2016-05-04
+==================
+
+  * deps: base64-url@1.2.2
+
+2.1.0 / 2016-01-17
+==================
+
+  * Use `random-bytes` for byte source
+
+2.0.0 / 2015-05-08
+==================
+
+  * Use global `Promise` when returning a promise
+
+1.1.0 / 2015-02-01
+==================
+
+  * Use `crypto.randomBytes`, if available
+  * deps: base64-url@1.2.1
+
+1.0.3 / 2015-01-31
+==================
+
+  * Fix error branch that would throw
+  * deps: base64-url@1.2.0
+
+1.0.2 / 2015-01-08
+==================
+
+  * Remove dependency on `mz`
+
+1.0.1 / 2014-06-18
+==================
+
+  * Remove direct `bluebird` dependency
+
+1.0.0 / 2014-06-18
+==================
+
+  * Initial release
diff --git a/server/node_modules/uid-safe/LICENSE b/server/node_modules/uid-safe/LICENSE
new file mode 100644
index 0000000..c4b8a49
--- /dev/null
+++ b/server/node_modules/uid-safe/LICENSE
@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Jonathan Ong <me@jongleberry.com>
+Copyright (c) 2015-2017 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/uid-safe/README.md b/server/node_modules/uid-safe/README.md
new file mode 100644
index 0000000..fa02be8
--- /dev/null
+++ b/server/node_modules/uid-safe/README.md
@@ -0,0 +1,77 @@
+# uid-safe
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+URL and cookie safe UIDs
+
+Create cryptographically secure UIDs safe for both cookie and URL usage.
+This is in contrast to modules such as [rand-token](https://www.npmjs.com/package/rand-token)
+and [uid2](https://www.npmjs.com/package/uid2) whose UIDs are actually skewed
+due to the use of `%` and unnecessarily truncate the UID.
+Use this if you could still use UIDs with `-` and `_` in them.
+
+## Installation
+
+```sh
+$ npm install uid-safe
+```
+
+## API
+
+```js
+var uid = require('uid-safe')
+```
+
+### uid(byteLength, callback)
+
+Asynchronously create a UID with a specific byte length. Because `base64`
+encoding is used underneath, this is not the string length. For example,
+to create a UID of length 24, you want a byte length of 18.
+
+```js
+uid(18, function (err, string) {
+  if (err) throw err
+  // do something with the string
+})
+```
+
+### uid(byteLength)
+
+Asynchronously create a UID with a specific byte length and return a
+`Promise`.
+
+**Note**: To use promises in Node.js _prior to 0.12_, promises must be
+"polyfilled" using `global.Promise = require('bluebird')`.
+
+```js
+uid(18).then(function (string) {
+  // do something with the string
+})
+```
+
+### uid.sync(byteLength)
+
+A synchronous version of above.
+
+```js
+var string = uid.sync(18)
+```
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/uid-safe.svg
+[npm-url]: https://npmjs.org/package/uid-safe
+[node-version-image]: https://img.shields.io/node/v/uid-safe.svg
+[node-version-url]: https://nodejs.org/en/download/
+[travis-image]: https://img.shields.io/travis/crypto-utils/uid-safe/master.svg
+[travis-url]: https://travis-ci.org/crypto-utils/uid-safe
+[coveralls-image]: https://img.shields.io/coveralls/crypto-utils/uid-safe/master.svg
+[coveralls-url]: https://coveralls.io/r/crypto-utils/uid-safe?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/uid-safe.svg
+[downloads-url]: https://npmjs.org/package/uid-safe
diff --git a/server/node_modules/uid-safe/index.js b/server/node_modules/uid-safe/index.js
new file mode 100644
index 0000000..18e8492
--- /dev/null
+++ b/server/node_modules/uid-safe/index.js
@@ -0,0 +1,107 @@
+/*!
+ * uid-safe
+ * Copyright(c) 2014 Jonathan Ong
+ * Copyright(c) 2015-2017 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module dependencies.
+ * @private
+ */
+
+var randomBytes = require('random-bytes')
+
+/**
+ * Module variables.
+ * @private
+ */
+
+var EQUAL_END_REGEXP = /=+$/
+var PLUS_GLOBAL_REGEXP = /\+/g
+var SLASH_GLOBAL_REGEXP = /\//g
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = uid
+module.exports.sync = uidSync
+
+/**
+ * Create a unique ID.
+ *
+ * @param {number} length
+ * @param {function} [callback]
+ * @return {Promise}
+ * @public
+ */
+
+function uid (length, callback) {
+  // validate callback is a function, if provided
+  if (callback !== undefined && typeof callback !== 'function') {
+    throw new TypeError('argument callback must be a function')
+  }
+
+  // require the callback without promises
+  if (!callback && !global.Promise) {
+    throw new TypeError('argument callback is required')
+  }
+
+  if (callback) {
+    // classic callback style
+    return generateUid(length, callback)
+  }
+
+  return new Promise(function executor (resolve, reject) {
+    generateUid(length, function onUid (err, str) {
+      if (err) return reject(err)
+      resolve(str)
+    })
+  })
+}
+
+/**
+ * Create a unique ID sync.
+ *
+ * @param {number} length
+ * @return {string}
+ * @public
+ */
+
+function uidSync (length) {
+  return toString(randomBytes.sync(length))
+}
+
+/**
+ * Generate a unique ID string.
+ *
+ * @param {number} length
+ * @param {function} callback
+ * @private
+ */
+
+function generateUid (length, callback) {
+  randomBytes(length, function (err, buf) {
+    if (err) return callback(err)
+    callback(null, toString(buf))
+  })
+}
+
+/**
+ * Change a Buffer into a string.
+ *
+ * @param {Buffer} buf
+ * @return {string}
+ * @private
+ */
+
+function toString (buf) {
+  return buf.toString('base64')
+    .replace(EQUAL_END_REGEXP, '')
+    .replace(PLUS_GLOBAL_REGEXP, '-')
+    .replace(SLASH_GLOBAL_REGEXP, '_')
+}
diff --git a/server/node_modules/uid-safe/package.json b/server/node_modules/uid-safe/package.json
new file mode 100644
index 0000000..9d9ea4c
--- /dev/null
+++ b/server/node_modules/uid-safe/package.json
@@ -0,0 +1,46 @@
+{
+  "name": "uid-safe",
+  "description": "URL and cookie safe UIDs",
+  "version": "2.1.5",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "Jonathan Ong <me@jongleberry.com> (http://jongleberry.com)"
+  ],
+  "license": "MIT",
+  "repository": "crypto-utils/uid-safe",
+  "dependencies": {
+    "random-bytes": "~1.0.0"
+  },
+  "devDependencies": {
+    "bluebird": "3.5.0",
+    "eslint": "3.19.0",
+    "eslint-config-standard": "10.2.1",
+    "eslint-plugin-import": "2.7.0",
+    "eslint-plugin-node": "5.1.1",
+    "eslint-plugin-promise": "3.5.0",
+    "eslint-plugin-standard": "3.0.1",
+    "istanbul": "0.4.5",
+    "mocha": "2.5.3"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "test": "mocha --trace-deprecation --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --trace-deprecation --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --trace-deprecation --reporter spec --check-leaks test/"
+  },
+  "keywords": [
+    "random",
+    "generator",
+    "uid",
+    "safe"
+  ]
+}
diff --git a/server/node_modules/unique-filename/.nyc_output/54942.json b/server/node_modules/unique-filename/.nyc_output/54942.json
new file mode 100644
index 0000000..9e26dfe
--- /dev/null
+++ b/server/node_modules/unique-filename/.nyc_output/54942.json
@@ -0,0 +1 @@
+{}
\ No newline at end of file
diff --git a/server/node_modules/unique-filename/.nyc_output/54944.json b/server/node_modules/unique-filename/.nyc_output/54944.json
new file mode 100644
index 0000000..3ce72e5
--- /dev/null
+++ b/server/node_modules/unique-filename/.nyc_output/54944.json
@@ -0,0 +1 @@
+{"./index.js":{"path":"./index.js","s":{"1":1,"2":1,"3":1,"4":6},"b":{"1":[4,2]},"f":{"1":6},"fnMap":{"1":{"name":"(anonymous_1)","line":6,"loc":{"start":{"line":6,"column":17},"end":{"line":6,"column":51}}}},"statementMap":{"1":{"start":{"line":2,"column":0},"end":{"line":2,"column":26}},"2":{"start":{"line":4,"column":0},"end":{"line":4,"column":39}},"3":{"start":{"line":6,"column":0},"end":{"line":8,"column":1}},"4":{"start":{"line":7,"column":2},"end":{"line":7,"column":77}}},"branchMap":{"1":{"line":7,"type":"cond-expr","locations":[{"start":{"line":7,"column":39},"end":{"line":7,"column":51}},{"start":{"line":7,"column":54},"end":{"line":7,"column":56}}]}}}}
\ No newline at end of file
diff --git a/server/node_modules/unique-filename/LICENSE b/server/node_modules/unique-filename/LICENSE
new file mode 100644
index 0000000..69619c1
--- /dev/null
+++ b/server/node_modules/unique-filename/LICENSE
@@ -0,0 +1,5 @@
+Copyright npm, Inc
+
+Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/unique-filename/README.md b/server/node_modules/unique-filename/README.md
new file mode 100644
index 0000000..74b62b2
--- /dev/null
+++ b/server/node_modules/unique-filename/README.md
@@ -0,0 +1,33 @@
+unique-filename
+===============
+
+Generate a unique filename for use in temporary directories or caches.
+
+```
+var uniqueFilename = require('unique-filename')
+
+// returns something like: /tmp/912ec803b2ce49e4a541068d495ab570
+var randomTmpfile = uniqueFilename(os.tmpdir())
+
+// returns something like: /tmp/my-test-912ec803b2ce49e4a541068d495ab570
+var randomPrefixedTmpfile = uniqueFilename(os.tmpdir(), 'my-test')
+
+var uniqueTmpfile = uniqueFilename('/tmp', 'testing', '/my/thing/to/uniq/on')
+```
+
+### uniqueFilename(*dir*, *fileprefix*, *uniqstr*) → String
+
+Returns the full path of a unique filename that looks like:
+`dir/prefix-7ddd44c0`
+or `dir/7ddd44c0`
+
+*dir* – The path you want the filename in. `os.tmpdir()` is a good choice for this.
+
+*fileprefix* – A string to append prior to the unique part of the filename.
+The parameter is required if *uniqstr* is also passed in but is otherwise
+optional and can be `undefined`/`null`/`''`. If present and not empty
+then this string plus a hyphen are prepended to the unique part.
+
+*uniqstr* – Optional, if not passed the unique part of the resulting
+filename will be random.  If passed in it will be generated from this string
+in a reproducable way.
diff --git a/server/node_modules/unique-filename/coverage/__root__/index.html b/server/node_modules/unique-filename/coverage/__root__/index.html
new file mode 100644
index 0000000..cd55391
--- /dev/null
+++ b/server/node_modules/unique-filename/coverage/__root__/index.html
@@ -0,0 +1,73 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <title>Code coverage report for __root__/</title>
+    <meta charset="utf-8">
+    <link rel="stylesheet" href="../prettify.css">
+    <link rel="stylesheet" href="../base.css">
+    <style type='text/css'>
+        div.coverage-summary .sorter {
+            background-image: url(../sort-arrow-sprite.png);
+        }
+    </style>
+</head>
+<body>
+<div class="header high">
+    <h1>Code coverage report for <span class="entity">__root__/</span></h1>
+    <h2>
+        Statements: <span class="metric">100% <small>(4 / 4)</small></span>     
+        Branches: <span class="metric">100% <small>(2 / 2)</small></span>     
+        Functions: <span class="metric">100% <small>(1 / 1)</small></span>     
+        Lines: <span class="metric">100% <small>(4 / 4)</small></span>     
+        Ignored: <span class="metric"><span class="ignore-none">none</span></span>     
+    </h2>
+    <div class="path"><a href="../index.html">All files</a> » __root__/</div>
+</div>
+<div class="body">
+<div class="coverage-summary">
+<table>
+<thead>
+<tr>
+   <th data-col="file" data-fmt="html" data-html="true" class="file">File</th>
+   <th data-col="pic" data-type="number" data-fmt="html" data-html="true" class="pic"></th>
+   <th data-col="statements" data-type="number" data-fmt="pct" class="pct">Statements</th>
+   <th data-col="statements_raw" data-type="number" data-fmt="html" class="abs"></th>
+   <th data-col="branches" data-type="number" data-fmt="pct" class="pct">Branches</th>
+   <th data-col="branches_raw" data-type="number" data-fmt="html" class="abs"></th>
+   <th data-col="functions" data-type="number" data-fmt="pct" class="pct">Functions</th>
+   <th data-col="functions_raw" data-type="number" data-fmt="html" class="abs"></th>
+   <th data-col="lines" data-type="number" data-fmt="pct" class="pct">Lines</th>
+   <th data-col="lines_raw" data-type="number" data-fmt="html" class="abs"></th>
+</tr>
+</thead>
+<tbody><tr>
+	<td class="file high" data-value="index.js"><a href="index.js.html">index.js</a></td>
+	<td data-value="100" class="pic high"><span class="cover-fill cover-full" style="width: 100px;"></span><span class="cover-empty" style="width:0px;"></span></td>
+	<td data-value="100" class="pct high">100%</td>
+	<td data-value="4" class="abs high">(4 / 4)</td>
+	<td data-value="100" class="pct high">100%</td>
+	<td data-value="2" class="abs high">(2 / 2)</td>
+	<td data-value="100" class="pct high">100%</td>
+	<td data-value="1" class="abs high">(1 / 1)</td>
+	<td data-value="100" class="pct high">100%</td>
+	<td data-value="4" class="abs high">(4 / 4)</td>
+	</tr>
+
+</tbody>
+</table>
+</div>
+</div>
+<div class="footer">
+    <div class="meta">Generated by <a href="http://istanbul-js.org/" target="_blank">istanbul</a> at Thu Dec 03 2015 15:00:03 GMT-0800 (PST)</div>
+</div>
+<script src="../prettify.js"></script>
+<script>
+window.onload = function () {
+        if (typeof prettyPrint === 'function') {
+            prettyPrint();
+        }
+};
+</script>
+<script src="../sorter.js"></script>
+</body>
+</html>
diff --git a/server/node_modules/unique-filename/coverage/__root__/index.js.html b/server/node_modules/unique-filename/coverage/__root__/index.js.html
new file mode 100644
index 0000000..02e5768
--- /dev/null
+++ b/server/node_modules/unique-filename/coverage/__root__/index.js.html
@@ -0,0 +1,69 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <title>Code coverage report for index.js</title>
+    <meta charset="utf-8">
+    <link rel="stylesheet" href="../prettify.css">
+    <link rel="stylesheet" href="../base.css">
+    <style type='text/css'>
+        div.coverage-summary .sorter {
+            background-image: url(../sort-arrow-sprite.png);
+        }
+    </style>
+</head>
+<body>
+<div class="header high">
+    <h1>Code coverage report for <span class="entity">index.js</span></h1>
+    <h2>
+        Statements: <span class="metric">100% <small>(4 / 4)</small></span>     
+        Branches: <span class="metric">100% <small>(2 / 2)</small></span>     
+        Functions: <span class="metric">100% <small>(1 / 1)</small></span>     
+        Lines: <span class="metric">100% <small>(4 / 4)</small></span>     
+        Ignored: <span class="metric"><span class="ignore-none">none</span></span>     
+    </h2>
+    <div class="path"><a href="../index.html">All files</a> » <a href="index.html">__root__/</a> » index.js</div>
+</div>
+<div class="body">
+<pre><table class="coverage">
+<tr><td class="line-count">1
+2
+3
+4
+5
+6
+7
+8
+9</td><td class="line-coverage"><span class="cline-any cline-neutral"> </span>
+<span class="cline-any cline-yes">1</span>
+<span class="cline-any cline-neutral"> </span>
+<span class="cline-any cline-yes">1</span>
+<span class="cline-any cline-neutral"> </span>
+<span class="cline-any cline-yes">1</span>
+<span class="cline-any cline-yes">6</span>
+<span class="cline-any cline-neutral"> </span>
+<span class="cline-any cline-neutral"> </span></td><td class="text"><pre class="prettyprint lang-js">'use strict'
+var path = require('path')
+ 
+var uniqueSlug = require('unique-slug')
+ 
+module.exports = function (filepath, prefix, uniq) {
+  return path.join(filepath, (prefix ? prefix + '-' : '') + uniqueSlug(uniq))
+}
+ </pre></td></tr>
+</table></pre>
+
+</div>
+<div class="footer">
+    <div class="meta">Generated by <a href="http://istanbul-js.org/" target="_blank">istanbul</a> at Thu Dec 03 2015 15:00:03 GMT-0800 (PST)</div>
+</div>
+<script src="../prettify.js"></script>
+<script>
+window.onload = function () {
+        if (typeof prettyPrint === 'function') {
+            prettyPrint();
+        }
+};
+</script>
+<script src="../sorter.js"></script>
+</body>
+</html>
diff --git a/server/node_modules/unique-filename/coverage/base.css b/server/node_modules/unique-filename/coverage/base.css
new file mode 100644
index 0000000..a6a2f32
--- /dev/null
+++ b/server/node_modules/unique-filename/coverage/base.css
@@ -0,0 +1,182 @@
+body, html {
+    margin:0; padding: 0;
+}
+body {
+    font-family: Helvetica Neue, Helvetica,Arial;
+    font-size: 10pt;
+}
+div.header, div.footer {
+    background: #eee;
+    padding: 1em;
+}
+div.header {
+    z-index: 100;
+    position: fixed;
+    top: 0;
+    border-bottom: 1px solid #666;
+    width: 100%;
+}
+div.footer {
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diff --git a/server/node_modules/unique-filename/coverage/sort-arrow-sprite.png b/server/node_modules/unique-filename/coverage/sort-arrow-sprite.png
new file mode 100644
index 0000000..03f704a
Binary files /dev/null and b/server/node_modules/unique-filename/coverage/sort-arrow-sprite.png differ
diff --git a/server/node_modules/unique-filename/coverage/sorter.js b/server/node_modules/unique-filename/coverage/sorter.js
new file mode 100644
index 0000000..6afb736
--- /dev/null
+++ b/server/node_modules/unique-filename/coverage/sorter.js
@@ -0,0 +1,156 @@
+var addSorting = (function () {
+    "use strict";
+    var cols,
+        currentSort = {
+            index: 0,
+            desc: false
+        };
+
+    // returns the summary table element
+    function getTable() { return document.querySelector('.coverage-summary table'); }
+    // returns the thead element of the summary table
+    function getTableHeader() { return getTable().querySelector('thead tr'); }
+    // returns the tbody element of the summary table
+    function getTableBody() { return getTable().querySelector('tbody'); }
+    // returns the th element for nth column
+    function getNthColumn(n) { return getTableHeader().querySelectorAll('th')[n]; }
+
+    // loads all columns
+    function loadColumns() {
+        var colNodes = getTableHeader().querySelectorAll('th'),
+            colNode,
+            cols = [],
+            col,
+            i;
+
+        for (i = 0; i < colNodes.length; i += 1) {
+            colNode = colNodes[i];
+            col = {
+                key: colNode.getAttribute('data-col'),
+                sortable: !colNode.getAttribute('data-nosort'),
+                type: colNode.getAttribute('data-type') || 'string'
+            };
+            cols.push(col);
+            if (col.sortable) {
+                col.defaultDescSort = col.type === 'number';
+                colNode.innerHTML = colNode.innerHTML + '<span class="sorter"></span>';
+            }
+        }
+        return cols;
+    }
+    // attaches a data attribute to every tr element with an object
+    // of data values keyed by column name
+    function loadRowData(tableRow) {
+        var tableCols = tableRow.querySelectorAll('td'),
+            colNode,
+            col,
+            data = {},
+            i,
+            val;
+        for (i = 0; i < tableCols.length; i += 1) {
+            colNode = tableCols[i];
+            col = cols[i];
+            val = colNode.getAttribute('data-value');
+            if (col.type === 'number') {
+                val = Number(val);
+            }
+            data[col.key] = val;
+        }
+        return data;
+    }
+    // loads all row data
+    function loadData() {
+        var rows = getTableBody().querySelectorAll('tr'),
+            i;
+
+        for (i = 0; i < rows.length; i += 1) {
+            rows[i].data = loadRowData(rows[i]);
+        }
+    }
+    // sorts the table using the data for the ith column
+    function sortByIndex(index, desc) {
+        var key = cols[index].key,
+            sorter = function (a, b) {
+                a = a.data[key];
+                b = b.data[key];
+                return a < b ? -1 : a > b ? 1 : 0;
+            },
+            finalSorter = sorter,
+            tableBody = document.querySelector('.coverage-summary tbody'),
+            rowNodes = tableBody.querySelectorAll('tr'),
+            rows = [],
+            i;
+
+        if (desc) {
+            finalSorter = function (a, b) {
+                return -1 * sorter(a, b);
+            };
+        }
+
+        for (i = 0; i < rowNodes.length; i += 1) {
+            rows.push(rowNodes[i]);
+            tableBody.removeChild(rowNodes[i]);
+        }
+
+        rows.sort(finalSorter);
+
+        for (i = 0; i < rows.length; i += 1) {
+            tableBody.appendChild(rows[i]);
+        }
+    }
+    // removes sort indicators for current column being sorted
+    function removeSortIndicators() {
+        var col = getNthColumn(currentSort.index),
+            cls = col.className;
+
+        cls = cls.replace(/ sorted$/, '').replace(/ sorted-desc$/, '');
+        col.className = cls;
+    }
+    // adds sort indicators for current column being sorted
+    function addSortIndicators() {
+        getNthColumn(currentSort.index).className += currentSort.desc ? ' sorted-desc' : ' sorted';
+    }
+    // adds event listeners for all sorter widgets
+    function enableUI() {
+        var i,
+            el,
+            ithSorter = function ithSorter(i) {
+                var col = cols[i];
+
+                return function () {
+                    var desc = col.defaultDescSort;
+
+                    if (currentSort.index === i) {
+                        desc = !currentSort.desc;
+                    }
+                    sortByIndex(i, desc);
+                    removeSortIndicators();
+                    currentSort.index = i;
+                    currentSort.desc = desc;
+                    addSortIndicators();
+                };
+            };
+        for (i =0 ; i < cols.length; i += 1) {
+            if (cols[i].sortable) {
+                el = getNthColumn(i).querySelector('.sorter');
+                if (el.addEventListener) {
+                    el.addEventListener('click', ithSorter(i));
+                } else {
+                    el.attachEvent('onclick', ithSorter(i));
+                }
+            }
+        }
+    }
+    // adds sorting functionality to the UI
+    return function () {
+        if (!getTable()) {
+            return;
+        }
+        cols = loadColumns();
+        loadData(cols);
+        addSortIndicators();
+        enableUI();
+    };
+})();
+
+window.addEventListener('load', addSorting);
diff --git a/server/node_modules/unique-filename/index.js b/server/node_modules/unique-filename/index.js
new file mode 100644
index 0000000..02bf1e2
--- /dev/null
+++ b/server/node_modules/unique-filename/index.js
@@ -0,0 +1,8 @@
+'use strict'
+var path = require('path')
+
+var uniqueSlug = require('unique-slug')
+
+module.exports = function (filepath, prefix, uniq) {
+  return path.join(filepath, (prefix ? prefix + '-' : '') + uniqueSlug(uniq))
+}
diff --git a/server/node_modules/unique-filename/package.json b/server/node_modules/unique-filename/package.json
new file mode 100644
index 0000000..bc429aa
--- /dev/null
+++ b/server/node_modules/unique-filename/package.json
@@ -0,0 +1,27 @@
+{
+  "name": "unique-filename",
+  "version": "1.1.1",
+  "description": "Generate a unique filename for use in temporary directories or caches.",
+  "main": "index.js",
+  "scripts": {
+    "test": "standard && tap test"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/iarna/unique-filename.git"
+  },
+  "keywords": [],
+  "author": "Rebecca Turner <me@re-becca.org> (http://re-becca.org/)",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/iarna/unique-filename/issues"
+  },
+  "homepage": "https://github.com/iarna/unique-filename",
+  "devDependencies": {
+    "standard": "^5.4.1",
+    "tap": "^2.3.1"
+  },
+  "dependencies": {
+    "unique-slug": "^2.0.0"
+  }
+}
diff --git a/server/node_modules/unique-filename/test/index.js b/server/node_modules/unique-filename/test/index.js
new file mode 100644
index 0000000..105b4e5
--- /dev/null
+++ b/server/node_modules/unique-filename/test/index.js
@@ -0,0 +1,23 @@
+'sue strict'
+var t = require('tap')
+var uniqueFilename = require('../index.js')
+
+t.plan(6)
+
+var randomTmpfile = uniqueFilename('tmp')
+t.like(randomTmpfile, /^tmp.[a-f0-9]{8}$/, 'random tmp file')
+
+var randomAgain = uniqueFilename('tmp')
+t.notEqual(randomAgain, randomTmpfile, 'random tmp files are not the same')
+
+var randomPrefixedTmpfile = uniqueFilename('tmp', 'my-test')
+t.like(randomPrefixedTmpfile, /^tmp.my-test-[a-f0-9]{8}$/, 'random prefixed tmp file')
+
+var randomPrefixedAgain = uniqueFilename('tmp', 'my-test')
+t.notEqual(randomPrefixedAgain, randomPrefixedTmpfile, 'random prefixed tmp files are not the same')
+
+var uniqueTmpfile = uniqueFilename('tmp', 'testing', '/my/thing/to/uniq/on')
+t.like(uniqueTmpfile, /^tmp.testing-7ddd44c0$/, 'unique filename')
+
+var uniqueAgain = uniqueFilename('tmp', 'testing', '/my/thing/to/uniq/on')
+t.is(uniqueTmpfile, uniqueAgain, 'same unique string component produces same filename')
diff --git a/server/node_modules/unique-slug/.travis.yml b/server/node_modules/unique-slug/.travis.yml
new file mode 100644
index 0000000..5651fce
--- /dev/null
+++ b/server/node_modules/unique-slug/.travis.yml
@@ -0,0 +1,10 @@
+language: node_js
+sudo: false
+before_install:
+  - "npm -g install npm"
+node_js:
+  - "6"
+  - "8"
+  - "10"
+  - "lts/*"
+  - "node"
diff --git a/server/node_modules/unique-slug/LICENSE b/server/node_modules/unique-slug/LICENSE
new file mode 100644
index 0000000..7953647
--- /dev/null
+++ b/server/node_modules/unique-slug/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright npm, Inc
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/unique-slug/README.md b/server/node_modules/unique-slug/README.md
new file mode 100644
index 0000000..87f92f1
--- /dev/null
+++ b/server/node_modules/unique-slug/README.md
@@ -0,0 +1,19 @@
+unique-slug
+===========
+
+Generate a unique character string suitible for use in files and URLs.
+
+```
+var uniqueSlug = require('unique-slug')
+
+var randomSlug = uniqueSlug()
+var fileSlug = uniqueSlug('/etc/passwd')
+```
+
+### uniqueSlug(*str*) → String (8 chars)
+
+If *str* is passed in then the return value will be its murmur hash in
+hex.
+
+If *str* is not passed in, it will be 4 randomly generated bytes
+converted into 8 hexadecimal characters.
diff --git a/server/node_modules/unique-slug/index.js b/server/node_modules/unique-slug/index.js
new file mode 100644
index 0000000..fa4761a
--- /dev/null
+++ b/server/node_modules/unique-slug/index.js
@@ -0,0 +1,11 @@
+'use strict'
+var MurmurHash3 = require('imurmurhash')
+
+module.exports = function (uniq) {
+  if (uniq) {
+    var hash = new MurmurHash3(uniq)
+    return ('00000000' + hash.result().toString(16)).substr(-8)
+  } else {
+    return (Math.random().toString(16) + '0000000').substr(2, 8)
+  }
+}
diff --git a/server/node_modules/unique-slug/package.json b/server/node_modules/unique-slug/package.json
new file mode 100644
index 0000000..2142e68
--- /dev/null
+++ b/server/node_modules/unique-slug/package.json
@@ -0,0 +1,23 @@
+{
+  "name": "unique-slug",
+  "version": "2.0.2",
+  "description": "Generate a unique character string suitible for use in files and URLs.",
+  "main": "index.js",
+  "scripts": {
+    "test": "standard && tap --coverage test"
+  },
+  "keywords": [],
+  "author": "Rebecca Turner <me@re-becca.org> (http://re-becca.org)",
+  "license": "ISC",
+  "devDependencies": {
+    "standard": "^12.0.1",
+    "tap": "^12.7.0"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/iarna/unique-slug.git"
+  },
+  "dependencies": {
+    "imurmurhash": "^0.1.4"
+  }
+}
diff --git a/server/node_modules/unique-slug/test/index.js b/server/node_modules/unique-slug/test/index.js
new file mode 100644
index 0000000..0f4ccad
--- /dev/null
+++ b/server/node_modules/unique-slug/test/index.js
@@ -0,0 +1,13 @@
+'use strict'
+var t = require('tap')
+var uniqueSlug = require('../index.js')
+
+t.plan(5)
+var slugA = uniqueSlug()
+t.is(slugA.length, 8, 'random slugs are 8 chars')
+t.notEqual(slugA, uniqueSlug(), "two slugs aren't the same")
+var base = '/path/to/thingy'
+var slugB = uniqueSlug(base)
+t.is(slugB.length, 8, 'string based slugs are 8 chars')
+t.is(slugB, uniqueSlug(base), 'two string based slugs, from the same string are the same')
+t.notEqual(slugB, uniqueSlug(slugA), 'two string based slongs, from diff strings are different')
diff --git a/server/node_modules/unpipe/HISTORY.md b/server/node_modules/unpipe/HISTORY.md
new file mode 100644
index 0000000..85e0f8d
--- /dev/null
+++ b/server/node_modules/unpipe/HISTORY.md
@@ -0,0 +1,4 @@
+1.0.0 / 2015-06-14
+==================
+
+  * Initial release
diff --git a/server/node_modules/unpipe/LICENSE b/server/node_modules/unpipe/LICENSE
new file mode 100644
index 0000000..aed0138
--- /dev/null
+++ b/server/node_modules/unpipe/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2015 Douglas Christopher Wilson <doug@somethingdoug.com>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/unpipe/README.md b/server/node_modules/unpipe/README.md
new file mode 100644
index 0000000..e536ad2
--- /dev/null
+++ b/server/node_modules/unpipe/README.md
@@ -0,0 +1,43 @@
+# unpipe
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-image]][node-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Unpipe a stream from all destinations.
+
+## Installation
+
+```sh
+$ npm install unpipe
+```
+
+## API
+
+```js
+var unpipe = require('unpipe')
+```
+
+### unpipe(stream)
+
+Unpipes all destinations from a given stream. With stream 2+, this is
+equivalent to `stream.unpipe()`. When used with streams 1 style streams
+(typically Node.js 0.8 and below), this module attempts to undo the
+actions done in `stream.pipe(dest)`.
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/unpipe.svg
+[npm-url]: https://npmjs.org/package/unpipe
+[node-image]: https://img.shields.io/node/v/unpipe.svg
+[node-url]: http://nodejs.org/download/
+[travis-image]: https://img.shields.io/travis/stream-utils/unpipe.svg
+[travis-url]: https://travis-ci.org/stream-utils/unpipe
+[coveralls-image]: https://img.shields.io/coveralls/stream-utils/unpipe.svg
+[coveralls-url]: https://coveralls.io/r/stream-utils/unpipe?branch=master
+[downloads-image]: https://img.shields.io/npm/dm/unpipe.svg
+[downloads-url]: https://npmjs.org/package/unpipe
diff --git a/server/node_modules/unpipe/index.js b/server/node_modules/unpipe/index.js
new file mode 100644
index 0000000..15c3d97
--- /dev/null
+++ b/server/node_modules/unpipe/index.js
@@ -0,0 +1,69 @@
+/*!
+ * unpipe
+ * Copyright(c) 2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ * @public
+ */
+
+module.exports = unpipe
+
+/**
+ * Determine if there are Node.js pipe-like data listeners.
+ * @private
+ */
+
+function hasPipeDataListeners(stream) {
+  var listeners = stream.listeners('data')
+
+  for (var i = 0; i < listeners.length; i++) {
+    if (listeners[i].name === 'ondata') {
+      return true
+    }
+  }
+
+  return false
+}
+
+/**
+ * Unpipe a stream from all destinations.
+ *
+ * @param {object} stream
+ * @public
+ */
+
+function unpipe(stream) {
+  if (!stream) {
+    throw new TypeError('argument stream is required')
+  }
+
+  if (typeof stream.unpipe === 'function') {
+    // new-style
+    stream.unpipe()
+    return
+  }
+
+  // Node.js 0.8 hack
+  if (!hasPipeDataListeners(stream)) {
+    return
+  }
+
+  var listener
+  var listeners = stream.listeners('close')
+
+  for (var i = 0; i < listeners.length; i++) {
+    listener = listeners[i]
+
+    if (listener.name !== 'cleanup' && listener.name !== 'onclose') {
+      continue
+    }
+
+    // invoke the listener
+    listener.call(stream)
+  }
+}
diff --git a/server/node_modules/unpipe/package.json b/server/node_modules/unpipe/package.json
new file mode 100644
index 0000000..a2b7358
--- /dev/null
+++ b/server/node_modules/unpipe/package.json
@@ -0,0 +1,27 @@
+{
+  "name": "unpipe",
+  "description": "Unpipe a stream from all destinations",
+  "version": "1.0.0",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "repository": "stream-utils/unpipe",
+  "devDependencies": {
+    "istanbul": "0.3.15",
+    "mocha": "2.2.5",
+    "readable-stream": "1.1.13"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  }
+}
diff --git a/server/node_modules/util-deprecate/History.md b/server/node_modules/util-deprecate/History.md
new file mode 100644
index 0000000..acc8675
--- /dev/null
+++ b/server/node_modules/util-deprecate/History.md
@@ -0,0 +1,16 @@
+
+1.0.2 / 2015-10-07
+==================
+
+  * use try/catch when checking `localStorage` (#3, @kumavis)
+
+1.0.1 / 2014-11-25
+==================
+
+  * browser: use `console.warn()` for deprecation calls
+  * browser: more jsdocs
+
+1.0.0 / 2014-04-30
+==================
+
+  * initial commit
diff --git a/server/node_modules/util-deprecate/LICENSE b/server/node_modules/util-deprecate/LICENSE
new file mode 100644
index 0000000..6a60e8c
--- /dev/null
+++ b/server/node_modules/util-deprecate/LICENSE
@@ -0,0 +1,24 @@
+(The MIT License)
+
+Copyright (c) 2014 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/util-deprecate/README.md b/server/node_modules/util-deprecate/README.md
new file mode 100644
index 0000000..75622fa
--- /dev/null
+++ b/server/node_modules/util-deprecate/README.md
@@ -0,0 +1,53 @@
+util-deprecate
+==============
+### The Node.js `util.deprecate()` function with browser support
+
+In Node.js, this module simply re-exports the `util.deprecate()` function.
+
+In the web browser (i.e. via browserify), a browser-specific implementation
+of the `util.deprecate()` function is used.
+
+
+## API
+
+A `deprecate()` function is the only thing exposed by this module.
+
+``` javascript
+// setup:
+exports.foo = deprecate(foo, 'foo() is deprecated, use bar() instead');
+
+
+// users see:
+foo();
+// foo() is deprecated, use bar() instead
+foo();
+foo();
+```
+
+
+## License
+
+(The MIT License)
+
+Copyright (c) 2014 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/util-deprecate/browser.js b/server/node_modules/util-deprecate/browser.js
new file mode 100644
index 0000000..549ae2f
--- /dev/null
+++ b/server/node_modules/util-deprecate/browser.js
@@ -0,0 +1,67 @@
+
+/**
+ * Module exports.
+ */
+
+module.exports = deprecate;
+
+/**
+ * Mark that a method should not be used.
+ * Returns a modified function which warns once by default.
+ *
+ * If `localStorage.noDeprecation = true` is set, then it is a no-op.
+ *
+ * If `localStorage.throwDeprecation = true` is set, then deprecated functions
+ * will throw an Error when invoked.
+ *
+ * If `localStorage.traceDeprecation = true` is set, then deprecated functions
+ * will invoke `console.trace()` instead of `console.error()`.
+ *
+ * @param {Function} fn - the function to deprecate
+ * @param {String} msg - the string to print to the console when `fn` is invoked
+ * @returns {Function} a new "deprecated" version of `fn`
+ * @api public
+ */
+
+function deprecate (fn, msg) {
+  if (config('noDeprecation')) {
+    return fn;
+  }
+
+  var warned = false;
+  function deprecated() {
+    if (!warned) {
+      if (config('throwDeprecation')) {
+        throw new Error(msg);
+      } else if (config('traceDeprecation')) {
+        console.trace(msg);
+      } else {
+        console.warn(msg);
+      }
+      warned = true;
+    }
+    return fn.apply(this, arguments);
+  }
+
+  return deprecated;
+}
+
+/**
+ * Checks `localStorage` for boolean values for the given `name`.
+ *
+ * @param {String} name
+ * @returns {Boolean}
+ * @api private
+ */
+
+function config (name) {
+  // accessing global.localStorage can trigger a DOMException in sandboxed iframes
+  try {
+    if (!global.localStorage) return false;
+  } catch (_) {
+    return false;
+  }
+  var val = global.localStorage[name];
+  if (null == val) return false;
+  return String(val).toLowerCase() === 'true';
+}
diff --git a/server/node_modules/util-deprecate/node.js b/server/node_modules/util-deprecate/node.js
new file mode 100644
index 0000000..5e6fcff
--- /dev/null
+++ b/server/node_modules/util-deprecate/node.js
@@ -0,0 +1,6 @@
+
+/**
+ * For Node.js, simply re-export the core `util.deprecate` function.
+ */
+
+module.exports = require('util').deprecate;
diff --git a/server/node_modules/util-deprecate/package.json b/server/node_modules/util-deprecate/package.json
new file mode 100644
index 0000000..2e79f89
--- /dev/null
+++ b/server/node_modules/util-deprecate/package.json
@@ -0,0 +1,27 @@
+{
+  "name": "util-deprecate",
+  "version": "1.0.2",
+  "description": "The Node.js `util.deprecate()` function with browser support",
+  "main": "node.js",
+  "browser": "browser.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/TooTallNate/util-deprecate.git"
+  },
+  "keywords": [
+    "util",
+    "deprecate",
+    "browserify",
+    "browser",
+    "node"
+  ],
+  "author": "Nathan Rajlich <nathan@tootallnate.net> (http://n8.io/)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/TooTallNate/util-deprecate/issues"
+  },
+  "homepage": "https://github.com/TooTallNate/util-deprecate"
+}
diff --git a/server/node_modules/utils-merge/.npmignore b/server/node_modules/utils-merge/.npmignore
new file mode 100644
index 0000000..3e53844
--- /dev/null
+++ b/server/node_modules/utils-merge/.npmignore
@@ -0,0 +1,9 @@
+CONTRIBUTING.md
+Makefile
+docs/
+examples/
+reports/
+test/
+
+.jshintrc
+.travis.yml
diff --git a/server/node_modules/utils-merge/LICENSE b/server/node_modules/utils-merge/LICENSE
new file mode 100644
index 0000000..76f6d08
--- /dev/null
+++ b/server/node_modules/utils-merge/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2013-2017 Jared Hanson
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/utils-merge/README.md b/server/node_modules/utils-merge/README.md
new file mode 100644
index 0000000..0cb7117
--- /dev/null
+++ b/server/node_modules/utils-merge/README.md
@@ -0,0 +1,34 @@
+# utils-merge
+
+[![Version](https://img.shields.io/npm/v/utils-merge.svg?label=version)](https://www.npmjs.com/package/utils-merge)
+[![Build](https://img.shields.io/travis/jaredhanson/utils-merge.svg)](https://travis-ci.org/jaredhanson/utils-merge)
+[![Quality](https://img.shields.io/codeclimate/github/jaredhanson/utils-merge.svg?label=quality)](https://codeclimate.com/github/jaredhanson/utils-merge)
+[![Coverage](https://img.shields.io/coveralls/jaredhanson/utils-merge.svg)](https://coveralls.io/r/jaredhanson/utils-merge)
+[![Dependencies](https://img.shields.io/david/jaredhanson/utils-merge.svg)](https://david-dm.org/jaredhanson/utils-merge)
+
+
+Merges the properties from a source object into a destination object.
+
+## Install
+
+```bash
+$ npm install utils-merge
+```
+
+## Usage
+
+```javascript
+var a = { foo: 'bar' }
+  , b = { bar: 'baz' };
+
+merge(a, b);
+// => { foo: 'bar', bar: 'baz' }
+```
+
+## License
+
+[The MIT License](http://opensource.org/licenses/MIT)
+
+Copyright (c) 2013-2017 Jared Hanson <[http://jaredhanson.net/](http://jaredhanson.net/)>
+
+<a target='_blank' rel='nofollow' href='https://app.codesponsor.io/link/vK9dyjRnnWsMzzJTQ57fRJpH/jaredhanson/utils-merge'>  <img alt='Sponsor' width='888' height='68' src='https://app.codesponsor.io/embed/vK9dyjRnnWsMzzJTQ57fRJpH/jaredhanson/utils-merge.svg' /></a>
diff --git a/server/node_modules/utils-merge/index.js b/server/node_modules/utils-merge/index.js
new file mode 100644
index 0000000..4265c69
--- /dev/null
+++ b/server/node_modules/utils-merge/index.js
@@ -0,0 +1,23 @@
+/**
+ * Merge object b with object a.
+ *
+ *     var a = { foo: 'bar' }
+ *       , b = { bar: 'baz' };
+ *
+ *     merge(a, b);
+ *     // => { foo: 'bar', bar: 'baz' }
+ *
+ * @param {Object} a
+ * @param {Object} b
+ * @return {Object}
+ * @api public
+ */
+
+exports = module.exports = function(a, b){
+  if (a && b) {
+    for (var key in b) {
+      a[key] = b[key];
+    }
+  }
+  return a;
+};
diff --git a/server/node_modules/utils-merge/package.json b/server/node_modules/utils-merge/package.json
new file mode 100644
index 0000000..e36b078
--- /dev/null
+++ b/server/node_modules/utils-merge/package.json
@@ -0,0 +1,40 @@
+{
+  "name": "utils-merge",
+  "version": "1.0.1",
+  "description": "merge() utility function",
+  "keywords": [
+    "util"
+  ],
+  "author": {
+    "name": "Jared Hanson",
+    "email": "jaredhanson@gmail.com",
+    "url": "http://www.jaredhanson.net/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/jaredhanson/utils-merge.git"
+  },
+  "bugs": {
+    "url": "http://github.com/jaredhanson/utils-merge/issues"
+  },
+  "license": "MIT",
+  "licenses": [
+    {
+      "type": "MIT",
+      "url": "http://opensource.org/licenses/MIT"
+    }
+  ],
+  "main": "./index",
+  "dependencies": {},
+  "devDependencies": {
+    "make-node": "0.3.x",
+    "mocha": "1.x.x",
+    "chai": "1.x.x"
+  },
+  "engines": {
+    "node": ">= 0.4.0"
+  },
+  "scripts": {
+    "test": "node_modules/.bin/mocha --reporter spec --require test/bootstrap/node test/*.test.js"
+  }
+}
diff --git a/server/node_modules/vary/HISTORY.md b/server/node_modules/vary/HISTORY.md
new file mode 100644
index 0000000..f6cbcf7
--- /dev/null
+++ b/server/node_modules/vary/HISTORY.md
@@ -0,0 +1,39 @@
+1.1.2 / 2017-09-23
+==================
+
+  * perf: improve header token parsing speed
+
+1.1.1 / 2017-03-20
+==================
+
+  * perf: hoist regular expression
+
+1.1.0 / 2015-09-29
+==================
+
+  * Only accept valid field names in the `field` argument
+    - Ensures the resulting string is a valid HTTP header value
+
+1.0.1 / 2015-07-08
+==================
+
+  * Fix setting empty header from empty `field`
+  * perf: enable strict mode
+  * perf: remove argument reassignments
+
+1.0.0 / 2014-08-10
+==================
+
+  * Accept valid `Vary` header string as `field`
+  * Add `vary.append` for low-level string manipulation
+  * Move to `jshttp` orgainzation
+
+0.1.0 / 2014-06-05
+==================
+
+  * Support array of fields to set
+
+0.0.0 / 2014-06-04
+==================
+
+  * Initial release
diff --git a/server/node_modules/vary/LICENSE b/server/node_modules/vary/LICENSE
new file mode 100644
index 0000000..84441fb
--- /dev/null
+++ b/server/node_modules/vary/LICENSE
@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2014-2017 Douglas Christopher Wilson
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/server/node_modules/vary/README.md b/server/node_modules/vary/README.md
new file mode 100644
index 0000000..cc000b3
--- /dev/null
+++ b/server/node_modules/vary/README.md
@@ -0,0 +1,101 @@
+# vary
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Manipulate the HTTP Vary header
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally): 
+
+```sh
+$ npm install vary
+```
+
+## API
+
+
+
+```js
+var vary = require('vary')
+```
+
+### vary(res, field)
+
+Adds the given header `field` to the `Vary` response header of `res`.
+This can be a string of a single field, a string of a valid `Vary`
+header, or an array of multiple fields.
+
+This will append the header if not already listed, otherwise leaves
+it listed in the current location.
+
+
+
+```js
+// Append "Origin" to the Vary header of the response
+vary(res, 'Origin')
+```
+
+### vary.append(header, field)
+
+Adds the given header `field` to the `Vary` response header string `header`.
+This can be a string of a single field, a string of a valid `Vary` header,
+or an array of multiple fields.
+
+This will append the header if not already listed, otherwise leaves
+it listed in the current location. The new header string is returned.
+
+
+
+```js
+// Get header string appending "Origin" to "Accept, User-Agent"
+vary.append('Accept, User-Agent', 'Origin')
+```
+
+## Examples
+
+### Updating the Vary header when content is based on it
+
+```js
+var http = require('http')
+var vary = require('vary')
+
+http.createServer(function onRequest (req, res) {
+  // about to user-agent sniff
+  vary(res, 'User-Agent')
+
+  var ua = req.headers['user-agent'] || ''
+  var isMobile = /mobi|android|touch|mini/i.test(ua)
+
+  // serve site, depending on isMobile
+  res.setHeader('Content-Type', 'text/html')
+  res.end('You are (probably) ' + (isMobile ? '' : 'not ') + 'a mobile user')
+})
+```
+
+## Testing
+
+```sh
+$ npm test
+```
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/vary.svg
+[npm-url]: https://npmjs.org/package/vary
+[node-version-image]: https://img.shields.io/node/v/vary.svg
+[node-version-url]: https://nodejs.org/en/download
+[travis-image]: https://img.shields.io/travis/jshttp/vary/master.svg
+[travis-url]: https://travis-ci.org/jshttp/vary
+[coveralls-image]: https://img.shields.io/coveralls/jshttp/vary/master.svg
+[coveralls-url]: https://coveralls.io/r/jshttp/vary
+[downloads-image]: https://img.shields.io/npm/dm/vary.svg
+[downloads-url]: https://npmjs.org/package/vary
diff --git a/server/node_modules/vary/index.js b/server/node_modules/vary/index.js
new file mode 100644
index 0000000..5b5e741
--- /dev/null
+++ b/server/node_modules/vary/index.js
@@ -0,0 +1,149 @@
+/*!
+ * vary
+ * Copyright(c) 2014-2017 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
+'use strict'
+
+/**
+ * Module exports.
+ */
+
+module.exports = vary
+module.exports.append = append
+
+/**
+ * RegExp to match field-name in RFC 7230 sec 3.2
+ *
+ * field-name    = token
+ * token         = 1*tchar
+ * tchar         = "!" / "#" / "$" / "%" / "&" / "'" / "*"
+ *               / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
+ *               / DIGIT / ALPHA
+ *               ; any VCHAR, except delimiters
+ */
+
+var FIELD_NAME_REGEXP = /^[!#$%&'*+\-.^_`|~0-9A-Za-z]+$/
+
+/**
+ * Append a field to a vary header.
+ *
+ * @param {String} header
+ * @param {String|Array} field
+ * @return {String}
+ * @public
+ */
+
+function append (header, field) {
+  if (typeof header !== 'string') {
+    throw new TypeError('header argument is required')
+  }
+
+  if (!field) {
+    throw new TypeError('field argument is required')
+  }
+
+  // get fields array
+  var fields = !Array.isArray(field)
+    ? parse(String(field))
+    : field
+
+  // assert on invalid field names
+  for (var j = 0; j < fields.length; j++) {
+    if (!FIELD_NAME_REGEXP.test(fields[j])) {
+      throw new TypeError('field argument contains an invalid header name')
+    }
+  }
+
+  // existing, unspecified vary
+  if (header === '*') {
+    return header
+  }
+
+  // enumerate current values
+  var val = header
+  var vals = parse(header.toLowerCase())
+
+  // unspecified vary
+  if (fields.indexOf('*') !== -1 || vals.indexOf('*') !== -1) {
+    return '*'
+  }
+
+  for (var i = 0; i < fields.length; i++) {
+    var fld = fields[i].toLowerCase()
+
+    // append value (case-preserving)
+    if (vals.indexOf(fld) === -1) {
+      vals.push(fld)
+      val = val
+        ? val + ', ' + fields[i]
+        : fields[i]
+    }
+  }
+
+  return val
+}
+
+/**
+ * Parse a vary header into an array.
+ *
+ * @param {String} header
+ * @return {Array}
+ * @private
+ */
+
+function parse (header) {
+  var end = 0
+  var list = []
+  var start = 0
+
+  // gather tokens
+  for (var i = 0, len = header.length; i < len; i++) {
+    switch (header.charCodeAt(i)) {
+      case 0x20: /*   */
+        if (start === end) {
+          start = end = i + 1
+        }
+        break
+      case 0x2c: /* , */
+        list.push(header.substring(start, end))
+        start = end = i + 1
+        break
+      default:
+        end = i + 1
+        break
+    }
+  }
+
+  // final token
+  list.push(header.substring(start, end))
+
+  return list
+}
+
+/**
+ * Mark that a request is varied on a header field.
+ *
+ * @param {Object} res
+ * @param {String|Array} field
+ * @public
+ */
+
+function vary (res, field) {
+  if (!res || !res.getHeader || !res.setHeader) {
+    // quack quack
+    throw new TypeError('res argument is required')
+  }
+
+  // get existing header
+  var val = res.getHeader('Vary') || ''
+  var header = Array.isArray(val)
+    ? val.join(', ')
+    : String(val)
+
+  // set new header
+  if ((val = append(header, field))) {
+    res.setHeader('Vary', val)
+  }
+}
diff --git a/server/node_modules/vary/package.json b/server/node_modules/vary/package.json
new file mode 100644
index 0000000..028f72a
--- /dev/null
+++ b/server/node_modules/vary/package.json
@@ -0,0 +1,43 @@
+{
+  "name": "vary",
+  "description": "Manipulate the HTTP Vary header",
+  "version": "1.1.2",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "license": "MIT",
+  "keywords": [
+    "http",
+    "res",
+    "vary"
+  ],
+  "repository": "jshttp/vary",
+  "devDependencies": {
+    "beautify-benchmark": "0.2.4",
+    "benchmark": "2.1.4",
+    "eslint": "3.19.0",
+    "eslint-config-standard": "10.2.1",
+    "eslint-plugin-import": "2.7.0",
+    "eslint-plugin-markdown": "1.0.0-beta.6",
+    "eslint-plugin-node": "5.1.1",
+    "eslint-plugin-promise": "3.5.0",
+    "eslint-plugin-standard": "3.0.1",
+    "istanbul": "0.4.5",
+    "mocha": "2.5.3",
+    "supertest": "1.1.0"
+  },
+  "files": [
+    "HISTORY.md",
+    "LICENSE",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.8"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  }
+}
diff --git a/server/node_modules/which/CHANGELOG.md b/server/node_modules/which/CHANGELOG.md
new file mode 100644
index 0000000..7fb1f20
--- /dev/null
+++ b/server/node_modules/which/CHANGELOG.md
@@ -0,0 +1,166 @@
+# Changes
+
+
+## 2.0.2
+
+* Rename bin to `node-which`
+
+## 2.0.1
+
+* generate changelog and publish on version bump
+* enforce 100% test coverage
+* Promise interface
+
+## 2.0.0
+
+* Parallel tests, modern JavaScript, and drop support for node < 8
+
+## 1.3.1
+
+* update deps
+* update travis
+
+## v1.3.0
+
+* Add nothrow option to which.sync
+* update tap
+
+## v1.2.14
+
+* appveyor: drop node 5 and 0.x
+* travis-ci: add node 6, drop 0.x
+
+## v1.2.13
+
+* test: Pass missing option to pass on windows
+* update tap
+* update isexe to 2.0.0
+* neveragain.tech pledge request
+
+## v1.2.12
+
+* Removed unused require
+
+## v1.2.11
+
+* Prevent changelog script from being included in package
+
+## v1.2.10
+
+* Use env.PATH only, not env.Path
+
+## v1.2.9
+
+* fix for paths starting with ../
+* Remove unused `is-absolute` module
+
+## v1.2.8
+
+* bullet items in changelog that contain (but don't start with) #
+
+## v1.2.7
+
+* strip 'update changelog' changelog entries out of changelog
+
+## v1.2.6
+
+* make the changelog bulleted
+
+## v1.2.5
+
+* make a changelog, and keep it up to date
+* don't include tests in package
+* Properly handle relative-path executables
+* appveyor
+* Attach error code to Not Found error
+* Make tests pass on Windows
+
+## v1.2.4
+
+* Fix typo
+
+## v1.2.3
+
+* update isexe, fix regression in pathExt handling
+
+## v1.2.2
+
+* update deps, use isexe module, test windows
+
+## v1.2.1
+
+* Sometimes windows PATH entries are quoted
+* Fixed a bug in the check for group and user mode bits. This bug was introduced during refactoring for supporting strict mode.
+* doc cli
+
+## v1.2.0
+
+* Add support for opt.all and -as cli flags
+* test the bin
+* update travis
+* Allow checking for multiple programs in bin/which
+* tap 2
+
+## v1.1.2
+
+* travis
+* Refactored and fixed undefined error on Windows
+* Support strict mode
+
+## v1.1.1
+
+* test +g exes against secondary groups, if available
+* Use windows exe semantics on cygwin & msys
+* cwd should be first in path on win32, not last
+* Handle lower-case 'env.Path' on Windows
+* Update docs
+* use single-quotes
+
+## v1.1.0
+
+* Add tests, depend on is-absolute
+
+## v1.0.9
+
+* which.js: root is allowed to execute files owned by anyone
+
+## v1.0.8
+
+* don't use graceful-fs
+
+## v1.0.7
+
+* add license to package.json
+
+## v1.0.6
+
+* isc license
+
+## 1.0.5
+
+* Awful typo
+
+## 1.0.4
+
+* Test for path absoluteness properly
+* win: Allow '' as a pathext if cmd has a . in it
+
+## 1.0.3
+
+* Remove references to execPath
+* Make `which.sync()` work on Windows by honoring the PATHEXT variable.
+* Make `isExe()` always return true on Windows.
+* MIT
+
+## 1.0.2
+
+* Only files can be exes
+
+## 1.0.1
+
+* Respect the PATHEXT env for win32 support
+* should 0755 the bin
+* binary
+* guts
+* package
+* 1st
diff --git a/server/node_modules/which/LICENSE b/server/node_modules/which/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/which/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/which/README.md b/server/node_modules/which/README.md
new file mode 100644
index 0000000..cd83350
--- /dev/null
+++ b/server/node_modules/which/README.md
@@ -0,0 +1,54 @@
+# which
+
+Like the unix `which` utility.
+
+Finds the first instance of a specified executable in the PATH
+environment variable.  Does not cache the results, so `hash -r` is not
+needed when the PATH changes.
+
+## USAGE
+
+```javascript
+var which = require('which')
+
+// async usage
+which('node', function (er, resolvedPath) {
+  // er is returned if no "node" is found on the PATH
+  // if it is found, then the absolute path to the exec is returned
+})
+
+// or promise
+which('node').then(resolvedPath => { ... }).catch(er => { ... not found ... })
+
+// sync usage
+// throws if not found
+var resolved = which.sync('node')
+
+// if nothrow option is used, returns null if not found
+resolved = which.sync('node', {nothrow: true})
+
+// Pass options to override the PATH and PATHEXT environment vars.
+which('node', { path: someOtherPath }, function (er, resolved) {
+  if (er)
+    throw er
+  console.log('found at %j', resolved)
+})
+```
+
+## CLI USAGE
+
+Same as the BSD `which(1)` binary.
+
+```
+usage: which [-as] program ...
+```
+
+## OPTIONS
+
+You may pass an options object as the second argument.
+
+- `path`: Use instead of the `PATH` environment variable.
+- `pathExt`: Use instead of the `PATHEXT` environment variable.
+- `all`: Return all matches, instead of just the first one.  Note that
+  this means the function returns an array of strings instead of a
+  single string.
diff --git a/server/node_modules/which/bin/node-which b/server/node_modules/which/bin/node-which
new file mode 100755
index 0000000..7cee372
--- /dev/null
+++ b/server/node_modules/which/bin/node-which
@@ -0,0 +1,52 @@
+#!/usr/bin/env node
+var which = require("../")
+if (process.argv.length < 3)
+  usage()
+
+function usage () {
+  console.error('usage: which [-as] program ...')
+  process.exit(1)
+}
+
+var all = false
+var silent = false
+var dashdash = false
+var args = process.argv.slice(2).filter(function (arg) {
+  if (dashdash || !/^-/.test(arg))
+    return true
+
+  if (arg === '--') {
+    dashdash = true
+    return false
+  }
+
+  var flags = arg.substr(1).split('')
+  for (var f = 0; f < flags.length; f++) {
+    var flag = flags[f]
+    switch (flag) {
+      case 's':
+        silent = true
+        break
+      case 'a':
+        all = true
+        break
+      default:
+        console.error('which: illegal option -- ' + flag)
+        usage()
+    }
+  }
+  return false
+})
+
+process.exit(args.reduce(function (pv, current) {
+  try {
+    var f = which.sync(current, { all: all })
+    if (all)
+      f = f.join('\n')
+    if (!silent)
+      console.log(f)
+    return pv;
+  } catch (e) {
+    return 1;
+  }
+}, 0))
diff --git a/server/node_modules/which/package.json b/server/node_modules/which/package.json
new file mode 100644
index 0000000..97ad7fb
--- /dev/null
+++ b/server/node_modules/which/package.json
@@ -0,0 +1,43 @@
+{
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me)",
+  "name": "which",
+  "description": "Like which(1) unix command. Find the first instance of an executable in the PATH.",
+  "version": "2.0.2",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/isaacs/node-which.git"
+  },
+  "main": "which.js",
+  "bin": {
+    "node-which": "./bin/node-which"
+  },
+  "license": "ISC",
+  "dependencies": {
+    "isexe": "^2.0.0"
+  },
+  "devDependencies": {
+    "mkdirp": "^0.5.0",
+    "rimraf": "^2.6.2",
+    "tap": "^14.6.9"
+  },
+  "scripts": {
+    "test": "tap",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "prepublish": "npm run changelog",
+    "prechangelog": "bash gen-changelog.sh",
+    "changelog": "git add CHANGELOG.md",
+    "postchangelog": "git commit -m 'update changelog - '${npm_package_version}",
+    "postpublish": "git push origin --follow-tags"
+  },
+  "files": [
+    "which.js",
+    "bin/node-which"
+  ],
+  "tap": {
+    "check-coverage": true
+  },
+  "engines": {
+    "node": ">= 8"
+  }
+}
diff --git a/server/node_modules/which/which.js b/server/node_modules/which/which.js
new file mode 100644
index 0000000..82afffd
--- /dev/null
+++ b/server/node_modules/which/which.js
@@ -0,0 +1,125 @@
+const isWindows = process.platform === 'win32' ||
+    process.env.OSTYPE === 'cygwin' ||
+    process.env.OSTYPE === 'msys'
+
+const path = require('path')
+const COLON = isWindows ? ';' : ':'
+const isexe = require('isexe')
+
+const getNotFoundError = (cmd) =>
+  Object.assign(new Error(`not found: ${cmd}`), { code: 'ENOENT' })
+
+const getPathInfo = (cmd, opt) => {
+  const colon = opt.colon || COLON
+
+  // If it has a slash, then we don't bother searching the pathenv.
+  // just check the file itself, and that's it.
+  const pathEnv = cmd.match(/\//) || isWindows && cmd.match(/\\/) ? ['']
+    : (
+      [
+        // windows always checks the cwd first
+        ...(isWindows ? [process.cwd()] : []),
+        ...(opt.path || process.env.PATH ||
+          /* istanbul ignore next: very unusual */ '').split(colon),
+      ]
+    )
+  const pathExtExe = isWindows
+    ? opt.pathExt || process.env.PATHEXT || '.EXE;.CMD;.BAT;.COM'
+    : ''
+  const pathExt = isWindows ? pathExtExe.split(colon) : ['']
+
+  if (isWindows) {
+    if (cmd.indexOf('.') !== -1 && pathExt[0] !== '')
+      pathExt.unshift('')
+  }
+
+  return {
+    pathEnv,
+    pathExt,
+    pathExtExe,
+  }
+}
+
+const which = (cmd, opt, cb) => {
+  if (typeof opt === 'function') {
+    cb = opt
+    opt = {}
+  }
+  if (!opt)
+    opt = {}
+
+  const { pathEnv, pathExt, pathExtExe } = getPathInfo(cmd, opt)
+  const found = []
+
+  const step = i => new Promise((resolve, reject) => {
+    if (i === pathEnv.length)
+      return opt.all && found.length ? resolve(found)
+        : reject(getNotFoundError(cmd))
+
+    const ppRaw = pathEnv[i]
+    const pathPart = /^".*"$/.test(ppRaw) ? ppRaw.slice(1, -1) : ppRaw
+
+    const pCmd = path.join(pathPart, cmd)
+    const p = !pathPart && /^\.[\\\/]/.test(cmd) ? cmd.slice(0, 2) + pCmd
+      : pCmd
+
+    resolve(subStep(p, i, 0))
+  })
+
+  const subStep = (p, i, ii) => new Promise((resolve, reject) => {
+    if (ii === pathExt.length)
+      return resolve(step(i + 1))
+    const ext = pathExt[ii]
+    isexe(p + ext, { pathExt: pathExtExe }, (er, is) => {
+      if (!er && is) {
+        if (opt.all)
+          found.push(p + ext)
+        else
+          return resolve(p + ext)
+      }
+      return resolve(subStep(p, i, ii + 1))
+    })
+  })
+
+  return cb ? step(0).then(res => cb(null, res), cb) : step(0)
+}
+
+const whichSync = (cmd, opt) => {
+  opt = opt || {}
+
+  const { pathEnv, pathExt, pathExtExe } = getPathInfo(cmd, opt)
+  const found = []
+
+  for (let i = 0; i < pathEnv.length; i ++) {
+    const ppRaw = pathEnv[i]
+    const pathPart = /^".*"$/.test(ppRaw) ? ppRaw.slice(1, -1) : ppRaw
+
+    const pCmd = path.join(pathPart, cmd)
+    const p = !pathPart && /^\.[\\\/]/.test(cmd) ? cmd.slice(0, 2) + pCmd
+      : pCmd
+
+    for (let j = 0; j < pathExt.length; j ++) {
+      const cur = p + pathExt[j]
+      try {
+        const is = isexe.sync(cur, { pathExt: pathExtExe })
+        if (is) {
+          if (opt.all)
+            found.push(cur)
+          else
+            return cur
+        }
+      } catch (ex) {}
+    }
+  }
+
+  if (opt.all && found.length)
+    return found
+
+  if (opt.nothrow)
+    return null
+
+  throw getNotFoundError(cmd)
+}
+
+module.exports = which
+which.sync = whichSync
diff --git a/server/node_modules/wide-align/LICENSE b/server/node_modules/wide-align/LICENSE
new file mode 100755
index 0000000..f4be44d
--- /dev/null
+++ b/server/node_modules/wide-align/LICENSE
@@ -0,0 +1,14 @@
+Copyright (c) 2015, Rebecca Turner <me@re-becca.org>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
diff --git a/server/node_modules/wide-align/README.md b/server/node_modules/wide-align/README.md
new file mode 100755
index 0000000..32f1be0
--- /dev/null
+++ b/server/node_modules/wide-align/README.md
@@ -0,0 +1,47 @@
+wide-align
+----------
+
+A wide-character aware text alignment function for use in terminals / on the
+console.
+
+### Usage
+
+```
+var align = require('wide-align')
+
+// Note that if you view this on a unicode console, all of the slashes are
+// aligned. This is because on a console, all narrow characters are
+// an en wide and all wide characters are an em. In browsers, this isn't
+// held to and wide characters like "古" can be less than two narrow
+// characters even with a fixed width font.
+
+console.log(align.center('abc', 10))     // '   abc    '
+console.log(align.center('古古古', 10))  // '  古古古  '
+console.log(align.left('abc', 10))       // 'abc       '
+console.log(align.left('古古古', 10))    // '古古古    '
+console.log(align.right('abc', 10))      // '       abc'
+console.log(align.right('古古古', 10))   // '    古古古'
+```
+
+### Functions
+
+#### `align.center(str, length)` → `str`
+
+Returns *str* with spaces added to both sides such that that it is *length*
+chars long and centered in the spaces.
+
+#### `align.left(str, length)` → `str`
+
+Returns *str* with spaces to the right such that it is *length* chars long.
+
+### `align.right(str, length)` → `str`
+
+Returns *str* with spaces to the left such that it is *length* chars long.
+
+### Origins
+
+These functions were originally taken from 
+[cliui](https://npmjs.com/package/cliui). Changes include switching to the
+MUCH faster pad generation function from
+[lodash](https://npmjs.com/package/lodash), making center alignment pad
+both sides and adding left alignment.
diff --git a/server/node_modules/wide-align/align.js b/server/node_modules/wide-align/align.js
new file mode 100755
index 0000000..4f94ca4
--- /dev/null
+++ b/server/node_modules/wide-align/align.js
@@ -0,0 +1,65 @@
+'use strict'
+var stringWidth = require('string-width')
+
+exports.center = alignCenter
+exports.left = alignLeft
+exports.right = alignRight
+
+// lodash's way of generating pad characters.
+
+function createPadding (width) {
+  var result = ''
+  var string = ' '
+  var n = width
+  do {
+    if (n % 2) {
+      result += string;
+    }
+    n = Math.floor(n / 2);
+    string += string;
+  } while (n);
+
+  return result;
+}
+
+function alignLeft (str, width) {
+  var trimmed = str.trimRight()
+  if (trimmed.length === 0 && str.length >= width) return str
+  var padding = ''
+  var strWidth = stringWidth(trimmed)
+
+  if (strWidth < width) {
+    padding = createPadding(width - strWidth)
+  }
+
+  return trimmed + padding
+}
+
+function alignRight (str, width) {
+  var trimmed = str.trimLeft()
+  if (trimmed.length === 0 && str.length >= width) return str
+  var padding = ''
+  var strWidth = stringWidth(trimmed)
+
+  if (strWidth < width) {
+    padding = createPadding(width - strWidth)
+  }
+
+  return padding + trimmed
+}
+
+function alignCenter (str, width) {
+  var trimmed = str.trim()
+  if (trimmed.length === 0 && str.length >= width) return str
+  var padLeft = ''
+  var padRight = ''
+  var strWidth = stringWidth(trimmed)
+
+  if (strWidth < width) {
+    var padLeftBy = parseInt((width - strWidth) / 2, 10) 
+    padLeft = createPadding(padLeftBy)
+    padRight = createPadding(width - (strWidth + padLeftBy))
+  }
+
+  return padLeft + trimmed + padRight
+}
diff --git a/server/node_modules/wide-align/package.json b/server/node_modules/wide-align/package.json
new file mode 100755
index 0000000..2dd2707
--- /dev/null
+++ b/server/node_modules/wide-align/package.json
@@ -0,0 +1,33 @@
+{
+  "name": "wide-align",
+  "version": "1.1.5",
+  "description": "A wide-character aware text alignment function for use on the console or with fixed width fonts.",
+  "main": "align.js",
+  "scripts": {
+    "test": "tap --coverage test/*.js"
+  },
+  "keywords": [
+    "wide",
+    "double",
+    "unicode",
+    "cjkv",
+    "pad",
+    "align"
+  ],
+  "author": "Rebecca Turner <me@re-becca.org> (http://re-becca.org/)",
+  "license": "ISC",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/iarna/wide-align"
+  },
+  "//": "But not version 5 of string-width, as that's ESM only",
+  "dependencies": {
+    "string-width": "^1.0.2 || 2 || 3 || 4"
+  },
+  "devDependencies": {
+    "tap": "*"
+  },
+  "files": [
+    "align.js"
+  ]
+}
diff --git a/server/node_modules/wrappy/LICENSE b/server/node_modules/wrappy/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/wrappy/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/wrappy/README.md b/server/node_modules/wrappy/README.md
new file mode 100644
index 0000000..98eab25
--- /dev/null
+++ b/server/node_modules/wrappy/README.md
@@ -0,0 +1,36 @@
+# wrappy
+
+Callback wrapping utility
+
+## USAGE
+
+```javascript
+var wrappy = require("wrappy")
+
+// var wrapper = wrappy(wrapperFunction)
+
+// make sure a cb is called only once
+// See also: http://npm.im/once for this specific use case
+var once = wrappy(function (cb) {
+  var called = false
+  return function () {
+    if (called) return
+    called = true
+    return cb.apply(this, arguments)
+  }
+})
+
+function printBoo () {
+  console.log('boo')
+}
+// has some rando property
+printBoo.iAmBooPrinter = true
+
+var onlyPrintOnce = once(printBoo)
+
+onlyPrintOnce() // prints 'boo'
+onlyPrintOnce() // does nothing
+
+// random property is retained!
+assert.equal(onlyPrintOnce.iAmBooPrinter, true)
+```
diff --git a/server/node_modules/wrappy/package.json b/server/node_modules/wrappy/package.json
new file mode 100644
index 0000000..1307520
--- /dev/null
+++ b/server/node_modules/wrappy/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "wrappy",
+  "version": "1.0.2",
+  "description": "Callback wrapping utility",
+  "main": "wrappy.js",
+  "files": [
+    "wrappy.js"
+  ],
+  "directories": {
+    "test": "test"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "tap": "^2.3.1"
+  },
+  "scripts": {
+    "test": "tap --coverage test/*.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/npm/wrappy"
+  },
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/npm/wrappy/issues"
+  },
+  "homepage": "https://github.com/npm/wrappy"
+}
diff --git a/server/node_modules/wrappy/wrappy.js b/server/node_modules/wrappy/wrappy.js
new file mode 100644
index 0000000..bb7e7d6
--- /dev/null
+++ b/server/node_modules/wrappy/wrappy.js
@@ -0,0 +1,33 @@
+// Returns a wrapper function that returns a wrapped callback
+// The wrapper function should do some stuff, and return a
+// presumably different callback function.
+// This makes sure that own properties are retained, so that
+// decorations and such are not lost along the way.
+module.exports = wrappy
+function wrappy (fn, cb) {
+  if (fn && cb) return wrappy(fn)(cb)
+
+  if (typeof fn !== 'function')
+    throw new TypeError('need wrapper function')
+
+  Object.keys(fn).forEach(function (k) {
+    wrapper[k] = fn[k]
+  })
+
+  return wrapper
+
+  function wrapper() {
+    var args = new Array(arguments.length)
+    for (var i = 0; i < args.length; i++) {
+      args[i] = arguments[i]
+    }
+    var ret = fn.apply(this, args)
+    var cb = args[args.length-1]
+    if (typeof ret === 'function' && ret !== cb) {
+      Object.keys(cb).forEach(function (k) {
+        ret[k] = cb[k]
+      })
+    }
+    return ret
+  }
+}
diff --git a/server/node_modules/xtend/.jshintrc b/server/node_modules/xtend/.jshintrc
new file mode 100644
index 0000000..77887b5
--- /dev/null
+++ b/server/node_modules/xtend/.jshintrc
@@ -0,0 +1,30 @@
+{
+    "maxdepth": 4,
+    "maxstatements": 200,
+    "maxcomplexity": 12,
+    "maxlen": 80,
+    "maxparams": 5,
+
+    "curly": true,
+    "eqeqeq": true,
+    "immed": true,
+    "latedef": false,
+    "noarg": true,
+    "noempty": true,
+    "nonew": true,
+    "undef": true,
+    "unused": "vars",
+    "trailing": true,
+
+    "quotmark": true,
+    "expr": true,
+    "asi": true,
+
+    "browser": false,
+    "esnext": true,
+    "devel": false,
+    "node": false,
+    "nonstandard": false,
+
+    "predef": ["require", "module", "__dirname", "__filename"]
+}
diff --git a/server/node_modules/xtend/LICENSE b/server/node_modules/xtend/LICENSE
new file mode 100644
index 0000000..0099f4f
--- /dev/null
+++ b/server/node_modules/xtend/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+Copyright (c) 2012-2014 Raynos.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/server/node_modules/xtend/README.md b/server/node_modules/xtend/README.md
new file mode 100644
index 0000000..4a2703c
--- /dev/null
+++ b/server/node_modules/xtend/README.md
@@ -0,0 +1,32 @@
+# xtend
+
+[![browser support][3]][4]
+
+[![locked](http://badges.github.io/stability-badges/dist/locked.svg)](http://github.com/badges/stability-badges)
+
+Extend like a boss
+
+xtend is a basic utility library which allows you to extend an object by appending all of the properties from each object in a list. When there are identical properties, the right-most property takes precedence.
+
+## Examples
+
+```js
+var extend = require("xtend")
+
+// extend returns a new object. Does not mutate arguments
+var combination = extend({
+    a: "a",
+    b: "c"
+}, {
+    b: "b"
+})
+// { a: "a", b: "b" }
+```
+
+## Stability status: Locked
+
+## MIT Licensed 
+
+
+  [3]: http://ci.testling.com/Raynos/xtend.png
+  [4]: http://ci.testling.com/Raynos/xtend
diff --git a/server/node_modules/xtend/immutable.js b/server/node_modules/xtend/immutable.js
new file mode 100644
index 0000000..94889c9
--- /dev/null
+++ b/server/node_modules/xtend/immutable.js
@@ -0,0 +1,19 @@
+module.exports = extend
+
+var hasOwnProperty = Object.prototype.hasOwnProperty;
+
+function extend() {
+    var target = {}
+
+    for (var i = 0; i < arguments.length; i++) {
+        var source = arguments[i]
+
+        for (var key in source) {
+            if (hasOwnProperty.call(source, key)) {
+                target[key] = source[key]
+            }
+        }
+    }
+
+    return target
+}
diff --git a/server/node_modules/xtend/mutable.js b/server/node_modules/xtend/mutable.js
new file mode 100644
index 0000000..72debed
--- /dev/null
+++ b/server/node_modules/xtend/mutable.js
@@ -0,0 +1,17 @@
+module.exports = extend
+
+var hasOwnProperty = Object.prototype.hasOwnProperty;
+
+function extend(target) {
+    for (var i = 1; i < arguments.length; i++) {
+        var source = arguments[i]
+
+        for (var key in source) {
+            if (hasOwnProperty.call(source, key)) {
+                target[key] = source[key]
+            }
+        }
+    }
+
+    return target
+}
diff --git a/server/node_modules/xtend/package.json b/server/node_modules/xtend/package.json
new file mode 100644
index 0000000..f7a39d1
--- /dev/null
+++ b/server/node_modules/xtend/package.json
@@ -0,0 +1,55 @@
+{
+  "name": "xtend",
+  "version": "4.0.2",
+  "description": "extend like a boss",
+  "keywords": [
+    "extend",
+    "merge",
+    "options",
+    "opts",
+    "object",
+    "array"
+  ],
+  "author": "Raynos <raynos2@gmail.com>",
+  "repository": "git://github.com/Raynos/xtend.git",
+  "main": "immutable",
+  "scripts": {
+    "test": "node test"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "tape": "~1.1.0"
+  },
+  "homepage": "https://github.com/Raynos/xtend",
+  "contributors": [
+    {
+      "name": "Jake Verbaten"
+    },
+    {
+      "name": "Matt Esch"
+    }
+  ],
+  "bugs": {
+    "url": "https://github.com/Raynos/xtend/issues",
+    "email": "raynos2@gmail.com"
+  },
+  "license": "MIT",
+  "testling": {
+    "files": "test.js",
+    "browsers": [
+      "ie/7..latest",
+      "firefox/16..latest",
+      "firefox/nightly",
+      "chrome/22..latest",
+      "chrome/canary",
+      "opera/12..latest",
+      "opera/next",
+      "safari/5.1..latest",
+      "ipad/6.0..latest",
+      "iphone/6.0..latest"
+    ]
+  },
+  "engines": {
+    "node": ">=0.4"
+  }
+}
diff --git a/server/node_modules/xtend/test.js b/server/node_modules/xtend/test.js
new file mode 100644
index 0000000..b895b42
--- /dev/null
+++ b/server/node_modules/xtend/test.js
@@ -0,0 +1,103 @@
+var test = require("tape")
+var extend = require("./")
+var mutableExtend = require("./mutable")
+
+test("merge", function(assert) {
+    var a = { a: "foo" }
+    var b = { b: "bar" }
+
+    assert.deepEqual(extend(a, b), { a: "foo", b: "bar" })
+    assert.end()
+})
+
+test("replace", function(assert) {
+    var a = { a: "foo" }
+    var b = { a: "bar" }
+
+    assert.deepEqual(extend(a, b), { a: "bar" })
+    assert.end()
+})
+
+test("undefined", function(assert) {
+    var a = { a: undefined }
+    var b = { b: "foo" }
+
+    assert.deepEqual(extend(a, b), { a: undefined, b: "foo" })
+    assert.deepEqual(extend(b, a), { a: undefined, b: "foo" })
+    assert.end()
+})
+
+test("handle 0", function(assert) {
+    var a = { a: "default" }
+    var b = { a: 0 }
+
+    assert.deepEqual(extend(a, b), { a: 0 })
+    assert.deepEqual(extend(b, a), { a: "default" })
+    assert.end()
+})
+
+test("is immutable", function (assert) {
+    var record = {}
+
+    extend(record, { foo: "bar" })
+    assert.equal(record.foo, undefined)
+    assert.end()
+})
+
+test("null as argument", function (assert) {
+    var a = { foo: "bar" }
+    var b = null
+    var c = void 0
+
+    assert.deepEqual(extend(b, a, c), { foo: "bar" })
+    assert.end()
+})
+
+test("mutable", function (assert) {
+    var a = { foo: "bar" }
+
+    mutableExtend(a, { bar: "baz" })
+
+    assert.equal(a.bar, "baz")
+    assert.end()
+})
+
+test("null prototype", function(assert) {
+    var a = { a: "foo" }
+    var b = Object.create(null)
+    b.b = "bar";
+
+    assert.deepEqual(extend(a, b), { a: "foo", b: "bar" })
+    assert.end()
+})
+
+test("null prototype mutable", function (assert) {
+    var a = { foo: "bar" }
+    var b = Object.create(null)
+    b.bar = "baz";
+
+    mutableExtend(a, b)
+
+    assert.equal(a.bar, "baz")
+    assert.end()
+})
+
+test("prototype pollution", function (assert) {
+    var a = {}
+    var maliciousPayload = '{"__proto__":{"oops":"It works!"}}'
+
+    assert.strictEqual(a.oops, undefined)
+    extend({}, maliciousPayload)
+    assert.strictEqual(a.oops, undefined)
+    assert.end()
+})
+
+test("prototype pollution mutable", function (assert) {
+    var a = {}
+    var maliciousPayload = '{"__proto__":{"oops":"It works!"}}'
+
+    assert.strictEqual(a.oops, undefined)
+    mutableExtend({}, maliciousPayload)
+    assert.strictEqual(a.oops, undefined)
+    assert.end()
+})
diff --git a/server/node_modules/yallist/LICENSE b/server/node_modules/yallist/LICENSE
new file mode 100644
index 0000000..19129e3
--- /dev/null
+++ b/server/node_modules/yallist/LICENSE
@@ -0,0 +1,15 @@
+The ISC License
+
+Copyright (c) Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/server/node_modules/yallist/README.md b/server/node_modules/yallist/README.md
new file mode 100644
index 0000000..f586101
--- /dev/null
+++ b/server/node_modules/yallist/README.md
@@ -0,0 +1,204 @@
+# yallist
+
+Yet Another Linked List
+
+There are many doubly-linked list implementations like it, but this
+one is mine.
+
+For when an array would be too big, and a Map can't be iterated in
+reverse order.
+
+
+[![Build Status](https://travis-ci.org/isaacs/yallist.svg?branch=master)](https://travis-ci.org/isaacs/yallist) [![Coverage Status](https://coveralls.io/repos/isaacs/yallist/badge.svg?service=github)](https://coveralls.io/github/isaacs/yallist)
+
+## basic usage
+
+```javascript
+var yallist = require('yallist')
+var myList = yallist.create([1, 2, 3])
+myList.push('foo')
+myList.unshift('bar')
+// of course pop() and shift() are there, too
+console.log(myList.toArray()) // ['bar', 1, 2, 3, 'foo']
+myList.forEach(function (k) {
+  // walk the list head to tail
+})
+myList.forEachReverse(function (k, index, list) {
+  // walk the list tail to head
+})
+var myDoubledList = myList.map(function (k) {
+  return k + k
+})
+// now myDoubledList contains ['barbar', 2, 4, 6, 'foofoo']
+// mapReverse is also a thing
+var myDoubledListReverse = myList.mapReverse(function (k) {
+  return k + k
+}) // ['foofoo', 6, 4, 2, 'barbar']
+
+var reduced = myList.reduce(function (set, entry) {
+  set += entry
+  return set
+}, 'start')
+console.log(reduced) // 'startfoo123bar'
+```
+
+## api
+
+The whole API is considered "public".
+
+Functions with the same name as an Array method work more or less the
+same way.
+
+There's reverse versions of most things because that's the point.
+
+### Yallist
+
+Default export, the class that holds and manages a list.
+
+Call it with either a forEach-able (like an array) or a set of
+arguments, to initialize the list.
+
+The Array-ish methods all act like you'd expect.  No magic length,
+though, so if you change that it won't automatically prune or add
+empty spots.
+
+### Yallist.create(..)
+
+Alias for Yallist function.  Some people like factories.
+
+#### yallist.head
+
+The first node in the list
+
+#### yallist.tail
+
+The last node in the list
+
+#### yallist.length
+
+The number of nodes in the list.  (Change this at your peril.  It is
+not magic like Array length.)
+
+#### yallist.toArray()
+
+Convert the list to an array.
+
+#### yallist.forEach(fn, [thisp])
+
+Call a function on each item in the list.
+
+#### yallist.forEachReverse(fn, [thisp])
+
+Call a function on each item in the list, in reverse order.
+
+#### yallist.get(n)
+
+Get the data at position `n` in the list.  If you use this a lot,
+probably better off just using an Array.
+
+#### yallist.getReverse(n)
+
+Get the data at position `n`, counting from the tail.
+
+#### yallist.map(fn, thisp)
+
+Create a new Yallist with the result of calling the function on each
+item.
+
+#### yallist.mapReverse(fn, thisp)
+
+Same as `map`, but in reverse.
+
+#### yallist.pop()
+
+Get the data from the list tail, and remove the tail from the list.
+
+#### yallist.push(item, ...)
+
+Insert one or more items to the tail of the list.
+
+#### yallist.reduce(fn, initialValue)
+
+Like Array.reduce.
+
+#### yallist.reduceReverse
+
+Like Array.reduce, but in reverse.
+
+#### yallist.reverse
+
+Reverse the list in place.
+
+#### yallist.shift()
+
+Get the data from the list head, and remove the head from the list.
+
+#### yallist.slice([from], [to])
+
+Just like Array.slice, but returns a new Yallist.
+
+#### yallist.sliceReverse([from], [to])
+
+Just like yallist.slice, but the result is returned in reverse.
+
+#### yallist.toArray()
+
+Create an array representation of the list.
+
+#### yallist.toArrayReverse()
+
+Create a reversed array representation of the list.
+
+#### yallist.unshift(item, ...)
+
+Insert one or more items to the head of the list.
+
+#### yallist.unshiftNode(node)
+
+Move a Node object to the front of the list.  (That is, pull it out of
+wherever it lives, and make it the new head.)
+
+If the node belongs to a different list, then that list will remove it
+first.
+
+#### yallist.pushNode(node)
+
+Move a Node object to the end of the list.  (That is, pull it out of
+wherever it lives, and make it the new tail.)
+
+If the node belongs to a list already, then that list will remove it
+first.
+
+#### yallist.removeNode(node)
+
+Remove a node from the list, preserving referential integrity of head
+and tail and other nodes.
+
+Will throw an error if you try to have a list remove a node that
+doesn't belong to it.
+
+### Yallist.Node
+
+The class that holds the data and is actually the list.
+
+Call with `var n = new Node(value, previousNode, nextNode)`
+
+Note that if you do direct operations on Nodes themselves, it's very
+easy to get into weird states where the list is broken.  Be careful :)
+
+#### node.next
+
+The next node in the list.
+
+#### node.prev
+
+The previous node in the list.
+
+#### node.value
+
+The data the node contains.
+
+#### node.list
+
+The list to which this node belongs.  (Null if it does not belong to
+any list.)
diff --git a/server/node_modules/yallist/iterator.js b/server/node_modules/yallist/iterator.js
new file mode 100644
index 0000000..d41c97a
--- /dev/null
+++ b/server/node_modules/yallist/iterator.js
@@ -0,0 +1,8 @@
+'use strict'
+module.exports = function (Yallist) {
+  Yallist.prototype[Symbol.iterator] = function* () {
+    for (let walker = this.head; walker; walker = walker.next) {
+      yield walker.value
+    }
+  }
+}
diff --git a/server/node_modules/yallist/package.json b/server/node_modules/yallist/package.json
new file mode 100644
index 0000000..8a08386
--- /dev/null
+++ b/server/node_modules/yallist/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "yallist",
+  "version": "4.0.0",
+  "description": "Yet Another Linked List",
+  "main": "yallist.js",
+  "directories": {
+    "test": "test"
+  },
+  "files": [
+    "yallist.js",
+    "iterator.js"
+  ],
+  "dependencies": {},
+  "devDependencies": {
+    "tap": "^12.1.0"
+  },
+  "scripts": {
+    "test": "tap test/*.js --100",
+    "preversion": "npm test",
+    "postversion": "npm publish",
+    "postpublish": "git push origin --all; git push origin --tags"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/isaacs/yallist.git"
+  },
+  "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me/)",
+  "license": "ISC"
+}
diff --git a/server/node_modules/yallist/yallist.js b/server/node_modules/yallist/yallist.js
new file mode 100644
index 0000000..4e83ab1
--- /dev/null
+++ b/server/node_modules/yallist/yallist.js
@@ -0,0 +1,426 @@
+'use strict'
+module.exports = Yallist
+
+Yallist.Node = Node
+Yallist.create = Yallist
+
+function Yallist (list) {
+  var self = this
+  if (!(self instanceof Yallist)) {
+    self = new Yallist()
+  }
+
+  self.tail = null
+  self.head = null
+  self.length = 0
+
+  if (list && typeof list.forEach === 'function') {
+    list.forEach(function (item) {
+      self.push(item)
+    })
+  } else if (arguments.length > 0) {
+    for (var i = 0, l = arguments.length; i < l; i++) {
+      self.push(arguments[i])
+    }
+  }
+
+  return self
+}
+
+Yallist.prototype.removeNode = function (node) {
+  if (node.list !== this) {
+    throw new Error('removing node which does not belong to this list')
+  }
+
+  var next = node.next
+  var prev = node.prev
+
+  if (next) {
+    next.prev = prev
+  }
+
+  if (prev) {
+    prev.next = next
+  }
+
+  if (node === this.head) {
+    this.head = next
+  }
+  if (node === this.tail) {
+    this.tail = prev
+  }
+
+  node.list.length--
+  node.next = null
+  node.prev = null
+  node.list = null
+
+  return next
+}
+
+Yallist.prototype.unshiftNode = function (node) {
+  if (node === this.head) {
+    return
+  }
+
+  if (node.list) {
+    node.list.removeNode(node)
+  }
+
+  var head = this.head
+  node.list = this
+  node.next = head
+  if (head) {
+    head.prev = node
+  }
+
+  this.head = node
+  if (!this.tail) {
+    this.tail = node
+  }
+  this.length++
+}
+
+Yallist.prototype.pushNode = function (node) {
+  if (node === this.tail) {
+    return
+  }
+
+  if (node.list) {
+    node.list.removeNode(node)
+  }
+
+  var tail = this.tail
+  node.list = this
+  node.prev = tail
+  if (tail) {
+    tail.next = node
+  }
+
+  this.tail = node
+  if (!this.head) {
+    this.head = node
+  }
+  this.length++
+}
+
+Yallist.prototype.push = function () {
+  for (var i = 0, l = arguments.length; i < l; i++) {
+    push(this, arguments[i])
+  }
+  return this.length
+}
+
+Yallist.prototype.unshift = function () {
+  for (var i = 0, l = arguments.length; i < l; i++) {
+    unshift(this, arguments[i])
+  }
+  return this.length
+}
+
+Yallist.prototype.pop = function () {
+  if (!this.tail) {
+    return undefined
+  }
+
+  var res = this.tail.value
+  this.tail = this.tail.prev
+  if (this.tail) {
+    this.tail.next = null
+  } else {
+    this.head = null
+  }
+  this.length--
+  return res
+}
+
+Yallist.prototype.shift = function () {
+  if (!this.head) {
+    return undefined
+  }
+
+  var res = this.head.value
+  this.head = this.head.next
+  if (this.head) {
+    this.head.prev = null
+  } else {
+    this.tail = null
+  }
+  this.length--
+  return res
+}
+
+Yallist.prototype.forEach = function (fn, thisp) {
+  thisp = thisp || this
+  for (var walker = this.head, i = 0; walker !== null; i++) {
+    fn.call(thisp, walker.value, i, this)
+    walker = walker.next
+  }
+}
+
+Yallist.prototype.forEachReverse = function (fn, thisp) {
+  thisp = thisp || this
+  for (var walker = this.tail, i = this.length - 1; walker !== null; i--) {
+    fn.call(thisp, walker.value, i, this)
+    walker = walker.prev
+  }
+}
+
+Yallist.prototype.get = function (n) {
+  for (var i = 0, walker = this.head; walker !== null && i < n; i++) {
+    // abort out of the list early if we hit a cycle
+    walker = walker.next
+  }
+  if (i === n && walker !== null) {
+    return walker.value
+  }
+}
+
+Yallist.prototype.getReverse = function (n) {
+  for (var i = 0, walker = this.tail; walker !== null && i < n; i++) {
+    // abort out of the list early if we hit a cycle
+    walker = walker.prev
+  }
+  if (i === n && walker !== null) {
+    return walker.value
+  }
+}
+
+Yallist.prototype.map = function (fn, thisp) {
+  thisp = thisp || this
+  var res = new Yallist()
+  for (var walker = this.head; walker !== null;) {
+    res.push(fn.call(thisp, walker.value, this))
+    walker = walker.next
+  }
+  return res
+}
+
+Yallist.prototype.mapReverse = function (fn, thisp) {
+  thisp = thisp || this
+  var res = new Yallist()
+  for (var walker = this.tail; walker !== null;) {
+    res.push(fn.call(thisp, walker.value, this))
+    walker = walker.prev
+  }
+  return res
+}
+
+Yallist.prototype.reduce = function (fn, initial) {
+  var acc
+  var walker = this.head
+  if (arguments.length > 1) {
+    acc = initial
+  } else if (this.head) {
+    walker = this.head.next
+    acc = this.head.value
+  } else {
+    throw new TypeError('Reduce of empty list with no initial value')
+  }
+
+  for (var i = 0; walker !== null; i++) {
+    acc = fn(acc, walker.value, i)
+    walker = walker.next
+  }
+
+  return acc
+}
+
+Yallist.prototype.reduceReverse = function (fn, initial) {
+  var acc
+  var walker = this.tail
+  if (arguments.length > 1) {
+    acc = initial
+  } else if (this.tail) {
+    walker = this.tail.prev
+    acc = this.tail.value
+  } else {
+    throw new TypeError('Reduce of empty list with no initial value')
+  }
+
+  for (var i = this.length - 1; walker !== null; i--) {
+    acc = fn(acc, walker.value, i)
+    walker = walker.prev
+  }
+
+  return acc
+}
+
+Yallist.prototype.toArray = function () {
+  var arr = new Array(this.length)
+  for (var i = 0, walker = this.head; walker !== null; i++) {
+    arr[i] = walker.value
+    walker = walker.next
+  }
+  return arr
+}
+
+Yallist.prototype.toArrayReverse = function () {
+  var arr = new Array(this.length)
+  for (var i = 0, walker = this.tail; walker !== null; i++) {
+    arr[i] = walker.value
+    walker = walker.prev
+  }
+  return arr
+}
+
+Yallist.prototype.slice = function (from, to) {
+  to = to || this.length
+  if (to < 0) {
+    to += this.length
+  }
+  from = from || 0
+  if (from < 0) {
+    from += this.length
+  }
+  var ret = new Yallist()
+  if (to < from || to < 0) {
+    return ret
+  }
+  if (from < 0) {
+    from = 0
+  }
+  if (to > this.length) {
+    to = this.length
+  }
+  for (var i = 0, walker = this.head; walker !== null && i < from; i++) {
+    walker = walker.next
+  }
+  for (; walker !== null && i < to; i++, walker = walker.next) {
+    ret.push(walker.value)
+  }
+  return ret
+}
+
+Yallist.prototype.sliceReverse = function (from, to) {
+  to = to || this.length
+  if (to < 0) {
+    to += this.length
+  }
+  from = from || 0
+  if (from < 0) {
+    from += this.length
+  }
+  var ret = new Yallist()
+  if (to < from || to < 0) {
+    return ret
+  }
+  if (from < 0) {
+    from = 0
+  }
+  if (to > this.length) {
+    to = this.length
+  }
+  for (var i = this.length, walker = this.tail; walker !== null && i > to; i--) {
+    walker = walker.prev
+  }
+  for (; walker !== null && i > from; i--, walker = walker.prev) {
+    ret.push(walker.value)
+  }
+  return ret
+}
+
+Yallist.prototype.splice = function (start, deleteCount, ...nodes) {
+  if (start > this.length) {
+    start = this.length - 1
+  }
+  if (start < 0) {
+    start = this.length + start;
+  }
+
+  for (var i = 0, walker = this.head; walker !== null && i < start; i++) {
+    walker = walker.next
+  }
+
+  var ret = []
+  for (var i = 0; walker && i < deleteCount; i++) {
+    ret.push(walker.value)
+    walker = this.removeNode(walker)
+  }
+  if (walker === null) {
+    walker = this.tail
+  }
+
+  if (walker !== this.head && walker !== this.tail) {
+    walker = walker.prev
+  }
+
+  for (var i = 0; i < nodes.length; i++) {
+    walker = insert(this, walker, nodes[i])
+  }
+  return ret;
+}
+
+Yallist.prototype.reverse = function () {
+  var head = this.head
+  var tail = this.tail
+  for (var walker = head; walker !== null; walker = walker.prev) {
+    var p = walker.prev
+    walker.prev = walker.next
+    walker.next = p
+  }
+  this.head = tail
+  this.tail = head
+  return this
+}
+
+function insert (self, node, value) {
+  var inserted = node === self.head ?
+    new Node(value, null, node, self) :
+    new Node(value, node, node.next, self)
+
+  if (inserted.next === null) {
+    self.tail = inserted
+  }
+  if (inserted.prev === null) {
+    self.head = inserted
+  }
+
+  self.length++
+
+  return inserted
+}
+
+function push (self, item) {
+  self.tail = new Node(item, self.tail, null, self)
+  if (!self.head) {
+    self.head = self.tail
+  }
+  self.length++
+}
+
+function unshift (self, item) {
+  self.head = new Node(item, null, self.head, self)
+  if (!self.tail) {
+    self.tail = self.head
+  }
+  self.length++
+}
+
+function Node (value, prev, next, list) {
+  if (!(this instanceof Node)) {
+    return new Node(value, prev, next, list)
+  }
+
+  this.list = list
+  this.value = value
+
+  if (prev) {
+    prev.next = this
+    this.prev = prev
+  } else {
+    this.prev = null
+  }
+
+  if (next) {
+    next.prev = this
+    this.next = next
+  } else {
+    this.next = null
+  }
+}
+
+try {
+  // add if support for Symbol.iterator is present
+  require('./iterator.js')(Yallist)
+} catch (er) {}
diff --git a/server/package-lock.json b/server/package-lock.json
new file mode 100644
index 0000000..e1dfbc3
--- /dev/null
+++ b/server/package-lock.json
@@ -0,0 +1,2641 @@
+{
+  "name": "marketing-app-server",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "marketing-app-server",
+      "version": "1.0.0",
+      "dependencies": {
+        "bcrypt": "^6.0.0",
+        "better-sqlite3": "^11.7.0",
+        "connect-sqlite3": "^0.9.16",
+        "cors": "^2.8.5",
+        "express": "^4.21.0",
+        "express-session": "^1.19.0",
+        "multer": "^1.4.5-lts.1"
+      }
+    },
+    "node_modules/@gar/promisify": {
+      "version": "1.1.3",
+      "resolved": "https://registry.npmjs.org/@gar/promisify/-/promisify-1.1.3.tgz",
+      "integrity": "sha512-k2Ty1JcVojjJFwrg/ThKi2ujJ7XNLYaFGNB/bWT9wGR+oSMJHMa5w+CUq6p/pVrKeNNgA7pCqEcjSnHVoqJQFw==",
+      "license": "MIT",
+      "optional": true
+    },
+    "node_modules/@npmcli/fs": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/@npmcli/fs/-/fs-1.1.1.tgz",
+      "integrity": "sha512-8KG5RD0GVP4ydEzRn/I4BNDuxDtqVbOdm8675T49OIG/NGhaK0pjPX7ZcDlvKYbA+ulvVK3ztfcF4uBdOxuJbQ==",
+      "license": "ISC",
+      "optional": true,
+      "dependencies": {
+        "@gar/promisify": "^1.0.1",
+        "semver": "^7.3.5"
+      }
+    },
+    "node_modules/@npmcli/move-file": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/@npmcli/move-file/-/move-file-1.1.2.tgz",
+      "integrity": "sha512-1SUf/Cg2GzGDyaf15aR9St9TWlb+XvbZXWpDx8YKs7MLzMH/BCeopv+y9vzrzgkfykCGuWOlSu3mZhj2+FQcrg==",
+      "deprecated": "This functionality has been moved to @npmcli/fs",
+      "license": "MIT",
+      "optional": true,
+      "dependencies": {
+        "mkdirp": "^1.0.4",
+        "rimraf": "^3.0.2"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
+    "node_modules/@npmcli/move-file/node_modules/mkdirp": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-1.0.4.tgz",
+      "integrity": "sha512-vVqVZQyf3WLx2Shd0qJ9xuvqgAyKPLAiqITEtqW0oIUjzo3PePDd6fW9iFz30ef7Ysp/oiWqbhszeGWW2T6Gzw==",
+      "license": "MIT",
+      "optional": true,
+      "bin": {
+        "mkdirp": "bin/cmd.js"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
+    "node_modules/@tootallnate/once": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/@tootallnate/once/-/once-1.1.2.tgz",
+      "integrity": "sha512-RbzJvlNzmRq5c3O09UipeuXno4tA1FE6ikOjxZK0tuxVv3412l64l5t1W5pj4+rJq9vpkm/kwiR07aZXnsKPxw==",
+      "license": "MIT",
+      "optional": true,
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/abbrev": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/abbrev/-/abbrev-1.1.1.tgz",
+      "integrity": "sha512-nne9/IiQ/hzIhY6pdDnbBtz7DjPTKrY00P/zvPSm5pOFkl6xuGrGnXn/VtTNNfNtAfZ9/1RtehkszU9qcTii0Q==",
+      "license": "ISC",
+      "optional": true
+    },
+    "node_modules/accepts": {
+      "version": "1.3.8",
+      "resolved": "https://registry.npmjs.org/accepts/-/accepts-1.3.8.tgz",
+      "integrity": "sha512-PYAthTa2m2VKxuvSD3DPC/Gy+U+sOA1LAuT8mkmRuvw+NACSaeXEQ+NHcVF7rONl6qcaxV3Uuemwawk+7+SJLw==",
+      "license": "MIT",
+      "dependencies": {
+        "mime-types": "~2.1.34",
+        "negotiator": "0.6.3"
+      },
+      "engines": {
+        "node": ">= 0.6"
+      }
+    },
+    "node_modules/agent-base": {
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+        "mkdirp-classic": "^0.5.2",
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+      }
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+      "dependencies": {
+        "inherits": "^2.0.3",
+        "string_decoder": "^1.1.1",
+        "util-deprecate": "^1.0.1"
+      },
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+      }
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+      }
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+      "license": "ISC",
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+      }
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+      "bin": {
+        "mkdirp": "bin/cmd.js"
+      },
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+      }
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+      "engines": {
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+      }
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+      },
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+      "version": "1.6.18",
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+        "media-typer": "0.3.0",
+        "mime-types": "~2.1.24"
+      },
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+        "random-bytes": "~1.0.0"
+      },
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+      "license": "ISC",
+      "optional": true,
+      "dependencies": {
+        "unique-slug": "^2.0.0"
+      }
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+    "node_modules/unique-slug": {
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+      "license": "ISC",
+      "optional": true,
+      "dependencies": {
+        "imurmurhash": "^0.1.4"
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+      "license": "MIT",
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+      "license": "MIT",
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+      "license": "ISC",
+      "optional": true,
+      "dependencies": {
+        "isexe": "^2.0.0"
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+      "bin": {
+        "node-which": "bin/node-which"
+      },
+      "engines": {
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+    "node_modules/wide-align": {
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+      "license": "ISC",
+      "optional": true,
+      "dependencies": {
+        "string-width": "^1.0.2 || 2 || 3 || 4"
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+    "node_modules/wrappy": {
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+      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
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+      "license": "ISC"
+    },
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+      "resolved": "https://registry.npmjs.org/xtend/-/xtend-4.0.2.tgz",
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+      "license": "MIT",
+      "engines": {
+        "node": ">=0.4"
+      }
+    },
+    "node_modules/yallist": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/yallist/-/yallist-4.0.0.tgz",
+      "integrity": "sha512-3wdGidZyq5PB084XLES5TpOSRA3wjXAlIWMhum2kRcv/41Sn2emQ0dycQW4uZXLejwKvg6EsvbdlVL+FYEct7A==",
+      "license": "ISC"
+    }
+  }
+}
diff --git a/server/package.json b/server/package.json
new file mode 100644
index 0000000..dbd3a08
--- /dev/null
+++ b/server/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "marketing-app-server",
+  "version": "1.0.0",
+  "description": "Marketing Management App Backend",
+  "main": "server.js",
+  "scripts": {
+    "start": "node server.js",
+    "dev": "node --watch server.js"
+  },
+  "dependencies": {
+    "bcrypt": "^6.0.0",
+    "better-sqlite3": "^11.7.0",
+    "connect-sqlite3": "^0.9.16",
+    "cors": "^2.8.5",
+    "express": "^4.21.0",
+    "express-session": "^1.19.0",
+    "multer": "^1.4.5-lts.1"
+  }
+}
diff --git a/server/server.js b/server/server.js
new file mode 100644
index 0000000..ff60835
--- /dev/null
+++ b/server/server.js
@@ -0,0 +1,1403 @@
+const express = require('express');
+const cors = require('cors');
+const multer = require('multer');
+const path = require('path');
+const fs = require('fs');
+const bcrypt = require('bcrypt');
+const session = require('express-session');
+const SqliteStore = require('connect-sqlite3')(session);
+const { db, initialize } = require('./db');
+
+const app = express();
+const PORT = 3001;
+
+// Ensure uploads directory exists
+const uploadsDir = path.join(__dirname, 'uploads');
+if (!fs.existsSync(uploadsDir)) {
+  fs.mkdirSync(uploadsDir, { recursive: true });
+}
+
+// Middleware
+app.use(cors({ 
+  origin: function(origin, callback) {
+    // Allow requests with no origin (mobile apps, curl, etc)
+    if (!origin) return callback(null, true);
+    // Allow localhost and any IP on port 5173
+    if (origin.match(/^https?:\/\/(localhost|127\.0\.0\.1|(\d+\.){3}\d+):5173$/)) {
+      return callback(null, true);
+    }
+    callback(null, true); // Allow all for dev
+  },
+  credentials: true 
+}));
+app.use(express.json());
+
+// Session middleware
+app.use(session({
+  store: new SqliteStore({
+    db: 'sessions.db',
+    dir: __dirname
+  }),
+  secret: 'samaya-marketing-secret-key-change-in-production',
+  resave: false,
+  saveUninitialized: false,
+  cookie: {
+    secure: false, // set to true in production with HTTPS
+    httpOnly: true,
+    maxAge: 7 * 24 * 60 * 60 * 1000 // 7 days
+  }
+}));
+
+// Serve uploaded files
+app.use('/api/uploads', express.static(uploadsDir));
+
+// Multer config
+const storage = multer.diskStorage({
+  destination: (req, file, cb) => cb(null, uploadsDir),
+  filename: (req, file, cb) => {
+    const uniqueName = `${Date.now()}-${Math.round(Math.random() * 1e9)}${path.extname(file.originalname)}`;
+    cb(null, uniqueName);
+  }
+});
+const upload = multer({ storage, limits: { fileSize: 50 * 1024 * 1024 } }); // 50MB limit
+
+// Initialize database
+initialize();
+
+// ─── AUTH MIDDLEWARE ────────────────────────────────────────────
+
+function requireAuth(req, res, next) {
+  if (!req.session.userId) {
+    return res.status(401).json({ error: 'Authentication required' });
+  }
+  next();
+}
+
+function requireRole(...roles) {
+  return (req, res, next) => {
+    if (!req.session.userId) {
+      return res.status(401).json({ error: 'Authentication required' });
+    }
+    if (!roles.includes(req.session.userRole)) {
+      return res.status(403).json({ error: 'Insufficient permissions' });
+    }
+    next();
+  };
+}
+
+// Ownership check: contributors can only modify their own resources (or resources assigned to them)
+function requireOwnerOrRole(table, ...allowedRoles) {
+  return (req, res, next) => {
+    if (!req.session.userId) {
+      return res.status(401).json({ error: 'Authentication required' });
+    }
+    // Managers and superadmins bypass ownership check
+    if (allowedRoles.includes(req.session.userRole)) {
+      return next();
+    }
+    // Contributors must own the resource or be assigned to it
+    const row = db.prepare(`SELECT created_by_user_id, assigned_to FROM ${table} WHERE id = ?`).get(req.params.id);
+    if (!row) {
+      return res.status(404).json({ error: 'Not found' });
+    }
+    // Check if user owns the resource
+    if (row.created_by_user_id === req.session.userId) {
+      return next();
+    }
+    // Check if resource is assigned to user's team member
+    const currentUser = db.prepare('SELECT team_member_id FROM users WHERE id = ?').get(req.session.userId);
+    if (currentUser?.team_member_id && row.assigned_to === currentUser.team_member_id) {
+      return next();
+    }
+    return res.status(403).json({ error: 'You can only modify your own items' });
+  };
+}
+
+// ─── AUTH ROUTES ────────────────────────────────────────────────
+
+app.post('/api/auth/login', async (req, res) => {
+  const { email, password } = req.body;
+  if (!email || !password) {
+    return res.status(400).json({ error: 'Email and password are required' });
+  }
+
+  try {
+    const user = db.prepare('SELECT * FROM users WHERE email = ?').get(email);
+    if (!user) {
+      return res.status(401).json({ error: 'Invalid email or password' });
+    }
+
+    const validPassword = await bcrypt.compare(password, user.password_hash);
+    if (!validPassword) {
+      return res.status(401).json({ error: 'Invalid email or password' });
+    }
+
+    // Create session
+    req.session.userId = user.id;
+    req.session.userEmail = user.email;
+    req.session.userRole = user.role;
+    req.session.userName = user.name;
+    req.session.teamMemberId = user.team_member_id;
+
+    res.json({
+      user: {
+        id: user.id,
+        name: user.name,
+        email: user.email,
+        role: user.role,
+        avatar: user.avatar,
+        team_member_id: user.team_member_id,
+      },
+    });
+  } catch (err) {
+    console.error('Login error:', err);
+    res.status(500).json({ error: 'Login failed' });
+  }
+});
+
+app.post('/api/auth/logout', (req, res) => {
+  req.session.destroy(err => {
+    if (err) {
+      return res.status(500).json({ error: 'Logout failed' });
+    }
+    res.clearCookie('connect.sid');
+    res.json({ success: true });
+  });
+});
+
+app.get('/api/auth/me', requireAuth, (req, res) => {
+  const user = db.prepare('SELECT id, name, email, role, avatar, team_member_id, team_role, brands, phone, tutorial_completed, created_at FROM users WHERE id = ?').get(req.session.userId);
+  if (!user) {
+    return res.status(404).json({ error: 'User not found' });
+  }
+  // Check if profile is complete
+  const profileComplete = !!(user.team_role && user.brands);
+  res.json({ ...user, profileComplete, brands: JSON.parse(user.brands || '[]') });
+});
+
+// ─── SELF-SERVICE PROFILE ENDPOINTS ─────────────────────────────
+
+app.get('/api/users/me/profile', requireAuth, (req, res) => {
+  const user = db.prepare('SELECT id, name, email, role, team_role, brands, phone, avatar, tutorial_completed FROM users WHERE id = ?').get(req.session.userId);
+  if (!user) {
+    return res.status(404).json({ error: 'User not found' });
+  }
+  res.json({ ...user, brands: JSON.parse(user.brands || '[]') });
+});
+
+app.patch('/api/users/me/profile', requireAuth, async (req, res) => {
+  const { name, team_role, brands, phone } = req.body;
+  const updates = [];
+  const values = [];
+
+  if (name !== undefined) { updates.push('name = ?'); values.push(name); }
+  if (team_role !== undefined) { updates.push('team_role = ?'); values.push(team_role); }
+  if (phone !== undefined) { updates.push('phone = ?'); values.push(phone); }
+  if (brands !== undefined) {
+    updates.push('brands = ?');
+    values.push(JSON.stringify(brands));
+  }
+
+  if (updates.length === 0) {
+    return res.status(400).json({ error: 'No fields to update' });
+  }
+
+  try {
+    values.push(req.session.userId);
+    db.prepare(`UPDATE users SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+    
+    // Also update session if name changed
+    if (name !== undefined) {
+      req.session.userName = name;
+    }
+    
+    const user = db.prepare('SELECT id, name, email, role, team_role, brands, phone, avatar, tutorial_completed FROM users WHERE id = ?').get(req.session.userId);
+    res.json({ ...user, brands: JSON.parse(user.brands || '[]') });
+  } catch (err) {
+    console.error('Update profile error:', err);
+    res.status(500).json({ error: 'Failed to update profile' });
+  }
+});
+
+app.patch('/api/users/me/tutorial', requireAuth, (req, res) => {
+  const { completed } = req.body;
+  try {
+    db.prepare('UPDATE users SET tutorial_completed = ? WHERE id = ?').run(completed ? 1 : 0, req.session.userId);
+    res.json({ success: true, tutorial_completed: completed ? 1 : 0 });
+  } catch (err) {
+    console.error('Update tutorial error:', err);
+    res.status(500).json({ error: 'Failed to update tutorial status' });
+  }
+});
+
+// ─── USER MANAGEMENT (Superadmin only) ──────────────────────────
+
+app.get('/api/users', requireAuth, requireRole('superadmin'), (req, res) => {
+  const users = db.prepare('SELECT id, name, email, role, avatar, team_member_id, created_at FROM users ORDER BY created_at DESC').all();
+  res.json(users);
+});
+
+app.post('/api/users', requireAuth, requireRole('superadmin'), async (req, res) => {
+  const { name, email, password, role, avatar, team_member_id } = req.body;
+  if (!name || !email || !password || !role) {
+    return res.status(400).json({ error: 'Name, email, password, and role are required' });
+  }
+
+  if (!['superadmin', 'manager', 'contributor'].includes(role)) {
+    return res.status(400).json({ error: 'Invalid role' });
+  }
+
+  try {
+    const existing = db.prepare('SELECT id FROM users WHERE email = ?').get(email);
+    if (existing) {
+      return res.status(409).json({ error: 'Email already exists' });
+    }
+
+    const passwordHash = await bcrypt.hash(password, 10);
+    const result = db.prepare(`
+      INSERT INTO users (name, email, password_hash, role, avatar, team_member_id)
+      VALUES (?, ?, ?, ?, ?, ?)
+    `).run(name, email, passwordHash, role, avatar || null, team_member_id || null);
+
+    const user = db.prepare('SELECT id, name, email, role, avatar, team_member_id, created_at FROM users WHERE id = ?').get(result.lastInsertRowid);
+    res.status(201).json(user);
+  } catch (err) {
+    console.error('Create user error:', err);
+    res.status(500).json({ error: 'Failed to create user' });
+  }
+});
+
+app.patch('/api/users/:id', requireAuth, requireRole('superadmin'), async (req, res) => {
+  const { id } = req.params;
+  const existing = db.prepare('SELECT * FROM users WHERE id = ?').get(id);
+  if (!existing) {
+    return res.status(404).json({ error: 'User not found' });
+  }
+
+  const { name, email, password, role, avatar } = req.body;
+  const updates = [];
+  const values = [];
+
+  if (name !== undefined) { updates.push('name = ?'); values.push(name); }
+  if (email !== undefined) { updates.push('email = ?'); values.push(email); }
+  if (role !== undefined) {
+    if (!['superadmin', 'manager', 'contributor'].includes(role)) {
+      return res.status(400).json({ error: 'Invalid role' });
+    }
+    updates.push('role = ?');
+    values.push(role);
+  }
+  if (avatar !== undefined) { updates.push('avatar = ?'); values.push(avatar); }
+  if (req.body.team_member_id !== undefined) { updates.push('team_member_id = ?'); values.push(req.body.team_member_id || null); }
+
+  if (password) {
+    const passwordHash = await bcrypt.hash(password, 10);
+    updates.push('password_hash = ?');
+    values.push(passwordHash);
+  }
+
+  if (updates.length === 0) {
+    return res.status(400).json({ error: 'No fields to update' });
+  }
+
+  try {
+    values.push(id);
+    db.prepare(`UPDATE users SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+    const user = db.prepare('SELECT id, name, email, role, avatar, team_member_id, created_at FROM users WHERE id = ?').get(id);
+    res.json(user);
+  } catch (err) {
+    console.error('Update user error:', err);
+    res.status(500).json({ error: 'Failed to update user' });
+  }
+});
+
+app.delete('/api/users/:id', requireAuth, requireRole('superadmin'), (req, res) => {
+  const { id } = req.params;
+
+  // Prevent deleting yourself
+  if (Number(id) === req.session.userId) {
+    return res.status(400).json({ error: 'Cannot delete your own account' });
+  }
+
+  const result = db.prepare('DELETE FROM users WHERE id = ?').run(id);
+  if (result.changes === 0) {
+    return res.status(404).json({ error: 'User not found' });
+  }
+  res.json({ success: true });
+});
+
+// ─── PERMISSIONS HELPER (for client-side checks) ────────────────
+
+app.get('/api/auth/permissions', requireAuth, (req, res) => {
+  const role = req.session.userRole;
+  const canManage = role === 'superadmin' || role === 'manager';
+  res.json({
+    role,
+    canCreateCampaigns: canManage,
+    canEditCampaigns: canManage,
+    canDeleteCampaigns: canManage,
+    canCreateProjects: canManage,
+    canEditProjects: canManage,
+    canDeleteProjects: canManage,
+    canManageFinance: canManage,
+    canManageTeam: canManage,
+    canManageUsers: role === 'superadmin',
+    // Posts & tasks: everyone can create, but only own (for contributors)
+    canCreatePosts: true,
+    canCreateTasks: true,
+    canEditAnyPost: canManage,
+    canDeleteAnyPost: canManage,
+    canEditAnyTask: canManage,
+    canDeleteAnyTask: canManage,
+  });
+});
+
+// ─── TEAM (Users with team info) ────────────────────────────────
+
+app.get('/api/users/team', requireAuth, (req, res) => {
+  const users = db.prepare(`
+    SELECT id, name, email, role, team_role, brands, phone, avatar, team_member_id, created_at 
+    FROM users 
+    WHERE team_member_id IS NOT NULL 
+    ORDER BY name
+  `).all();
+  
+  // Filter based on brand overlap for non-superadmins
+  let filteredUsers = users;
+  if (req.session.userRole !== 'superadmin') {
+    const currentUser = db.prepare('SELECT brands FROM users WHERE id = ?').get(req.session.userId);
+    const myBrands = JSON.parse(currentUser?.brands || '[]');
+    
+    filteredUsers = users.filter(u => {
+      const theirBrands = JSON.parse(u.brands || '[]');
+      // Always include self, or if there's brand overlap
+      return u.id === req.session.userId || theirBrands.some(b => myBrands.includes(b));
+    });
+  }
+  
+  // Return with both id and _id for compatibility
+  res.json(filteredUsers.map(u => ({ 
+    ...u, 
+    _id: u.id,
+    brands: JSON.parse(u.brands || '[]')
+  })));
+});
+
+app.post('/api/users/team', requireAuth, requireRole('superadmin', 'manager'), async (req, res) => {
+  const { name, email, password, team_role, brands, phone, role } = req.body;
+  if (!name) return res.status(400).json({ error: 'Name is required' });
+  if (!email) return res.status(400).json({ error: 'Email is required' });
+
+  // Managers can only create contributors
+  let userRole = role || 'contributor';
+  if (req.session.userRole === 'manager') {
+    if (userRole !== 'contributor') {
+      return res.status(403).json({ error: 'Managers can only create users with contributor role' });
+    }
+    userRole = 'contributor';
+  }
+
+  try {
+    // Check if email already exists
+    const existing = db.prepare('SELECT id FROM users WHERE email = ?').get(email);
+    if (existing) {
+      return res.status(409).json({ error: 'Email already exists' });
+    }
+
+    // First create team_member for backward compatibility
+    const tmResult = db.prepare(
+      'INSERT INTO team_members (name, email, role, brands, phone) VALUES (?, ?, ?, ?, ?)'
+    ).run(name, email, team_role || null, JSON.stringify(brands || []), phone || null);
+    
+    const teamMemberId = tmResult.lastInsertRowid;
+    
+    // Then create user account
+    const defaultPassword = password || 'changeme123';
+    const passwordHash = await bcrypt.hash(defaultPassword, 10);
+    const userResult = db.prepare(`
+      INSERT INTO users (name, email, password_hash, role, team_role, brands, phone, team_member_id)
+      VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+    `).run(name, email, passwordHash, userRole, team_role || null, JSON.stringify(brands || []), phone || null, teamMemberId);
+    
+    const user = db.prepare('SELECT id, name, email, role, team_role, brands, phone, avatar, team_member_id FROM users WHERE id = ?').get(userResult.lastInsertRowid);
+    res.status(201).json({ ...user, _id: user.id, brands: JSON.parse(user.brands || '[]') });
+  } catch (err) {
+    console.error('Create team member error:', err);
+    res.status(500).json({ error: 'Failed to create team member' });
+  }
+});
+
+app.patch('/api/users/team/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { id } = req.params;
+  const existing = db.prepare('SELECT * FROM users WHERE id = ?').get(id);
+  if (!existing) return res.status(404).json({ error: 'User not found' });
+
+  const updates = [];
+  const values = [];
+
+  if (req.body.name !== undefined) { updates.push('name = ?'); values.push(req.body.name); }
+  if (req.body.email !== undefined) { updates.push('email = ?'); values.push(req.body.email); }
+  if (req.body.team_role !== undefined) { updates.push('team_role = ?'); values.push(req.body.team_role); }
+  if (req.body.phone !== undefined) { updates.push('phone = ?'); values.push(req.body.phone); }
+  if (req.body.brands !== undefined) {
+    updates.push('brands = ?');
+    values.push(JSON.stringify(req.body.brands));
+  }
+
+  if (updates.length === 0) return res.status(400).json({ error: 'No fields to update' });
+
+  // Also update team_members table for backward compatibility
+  if (existing.team_member_id) {
+    const tmUpdates = [];
+    const tmValues = [];
+    if (req.body.name !== undefined) { tmUpdates.push('name = ?'); tmValues.push(req.body.name); }
+    if (req.body.email !== undefined) { tmUpdates.push('email = ?'); tmValues.push(req.body.email); }
+    if (req.body.team_role !== undefined) { tmUpdates.push('role = ?'); tmValues.push(req.body.team_role); }
+    if (req.body.phone !== undefined) { tmUpdates.push('phone = ?'); tmValues.push(req.body.phone); }
+    if (req.body.brands !== undefined) { tmUpdates.push('brands = ?'); tmValues.push(JSON.stringify(req.body.brands)); }
+    
+    if (tmUpdates.length > 0) {
+      tmValues.push(existing.team_member_id);
+      db.prepare(`UPDATE team_members SET ${tmUpdates.join(', ')} WHERE id = ?`).run(...tmValues);
+    }
+  }
+
+  values.push(id);
+  db.prepare(`UPDATE users SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+
+  const user = db.prepare('SELECT id, name, email, role, team_role, brands, phone, avatar, team_member_id FROM users WHERE id = ?').get(id);
+  res.json({ ...user, _id: user.id, brands: JSON.parse(user.brands || '[]') });
+});
+
+app.delete('/api/users/team/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const existing = db.prepare('SELECT team_member_id FROM users WHERE id = ?').get(req.params.id);
+  
+  // Delete user
+  const result = db.prepare('DELETE FROM users WHERE id = ?').run(req.params.id);
+  if (result.changes === 0) return res.status(404).json({ error: 'User not found' });
+  
+  // Also delete from team_members if exists
+  if (existing?.team_member_id) {
+    db.prepare('DELETE FROM team_members WHERE id = ?').run(existing.team_member_id);
+  }
+  
+  res.json({ success: true });
+});
+
+// ─── TEAM MEMBERS ───────────────────────────────────────────────
+
+app.get('/api/team', requireAuth, (req, res) => {
+  const members = db.prepare('SELECT * FROM team_members ORDER BY name').all();
+  res.json(members.map(m => ({ ...m, brands: JSON.parse(m.brands || '[]') })));
+});
+
+app.post('/api/team', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { name, email, role, avatar_url, brands } = req.body;
+  if (!name) return res.status(400).json({ error: 'Name is required' });
+
+  const result = db.prepare(
+    'INSERT INTO team_members (name, email, role, avatar_url, brands) VALUES (?, ?, ?, ?, ?)'
+  ).run(name, email || null, role || null, avatar_url || null, JSON.stringify(brands || []));
+
+  const member = db.prepare('SELECT * FROM team_members WHERE id = ?').get(result.lastInsertRowid);
+  res.status(201).json({ ...member, brands: JSON.parse(member.brands || '[]') });
+});
+
+app.patch('/api/team/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { id } = req.params;
+  const existing = db.prepare('SELECT * FROM team_members WHERE id = ?').get(id);
+  if (!existing) return res.status(404).json({ error: 'Member not found' });
+
+  const fields = ['name', 'email', 'role', 'avatar_url'];
+  const updates = [];
+  const values = [];
+
+  for (const field of fields) {
+    if (req.body[field] !== undefined) {
+      updates.push(`${field} = ?`);
+      values.push(req.body[field]);
+    }
+  }
+  if (req.body.brands !== undefined) {
+    updates.push('brands = ?');
+    values.push(JSON.stringify(req.body.brands));
+  }
+
+  if (updates.length === 0) return res.status(400).json({ error: 'No fields to update' });
+
+  values.push(id);
+  db.prepare(`UPDATE team_members SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+
+  const member = db.prepare('SELECT * FROM team_members WHERE id = ?').get(id);
+  res.json({ ...member, brands: JSON.parse(member.brands || '[]') });
+});
+
+app.delete('/api/team/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const result = db.prepare('DELETE FROM team_members WHERE id = ?').run(req.params.id);
+  if (result.changes === 0) return res.status(404).json({ error: 'Member not found' });
+  res.json({ success: true });
+});
+
+// ─── BRANDS ─────────────────────────────────────────────────────
+
+// Sync brands from NocoDB
+app.post('/api/brands/sync-nocodb', async (req, res) => {
+  try {
+    const NOCODB_URL = process.env.NOCODB_URL || 'http://localhost:8090';
+    const NOCODB_TOKEN = process.env.NOCODB_TOKEN || 'By-wCdkUm6N9JdfmNpGH2jd6LqEejwOXER7FMkgr';
+    const TABLE_ID = 'm9389nkt7ti11w3'; // Brands table in Samaya Digital Marketing base
+
+    const resp = await fetch(`${NOCODB_URL}/api/v2/tables/${TABLE_ID}/records?limit=100`, {
+      headers: { 'xc-token': NOCODB_TOKEN }
+    });
+    if (!resp.ok) throw new Error(`NocoDB returned ${resp.status}`);
+    const data = await resp.json();
+    const nocoBrands = data.list || [];
+
+    const findByName = db.prepare('SELECT id FROM brands WHERE name = ?');
+    const insertBrand = db.prepare('INSERT INTO brands (name, priority, color, icon) VALUES (?, ?, ?, ?)');
+    const updatePriority = db.prepare('UPDATE brands SET priority = ? WHERE id = ?');
+
+    const inserted = [];
+    const tx = db.transaction(() => {
+      for (const b of nocoBrands) {
+        const name = b.name_ar || b.Name || b.name;
+        if (!name) continue;
+        const priority = b.priority || 2;
+        const existing = findByName.get(name);
+        if (existing) {
+          updatePriority.run(priority, existing.id);
+        } else {
+          insertBrand.run(name, priority, null, null);
+        }
+        inserted.push(name);
+      }
+    });
+    tx();
+
+    res.json({ synced: inserted.length, brands: inserted });
+  } catch (err) {
+    console.error('NocoDB sync error:', err);
+    res.status(500).json({ error: err.message });
+  }
+});
+
+app.get('/api/brands', requireAuth, (req, res) => {
+  const brands = db.prepare('SELECT * FROM brands ORDER BY priority, name').all();
+  res.json(brands);
+});
+
+app.post('/api/brands', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { name, priority, color, icon } = req.body;
+  if (!name) return res.status(400).json({ error: 'Name is required' });
+
+  const result = db.prepare(
+    'INSERT INTO brands (name, priority, color, icon) VALUES (?, ?, ?, ?)'
+  ).run(name, priority || 2, color || null, icon || null);
+
+  const brand = db.prepare('SELECT * FROM brands WHERE id = ?').get(result.lastInsertRowid);
+  res.status(201).json(brand);
+});
+
+app.patch('/api/brands/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { id } = req.params;
+  const existing = db.prepare('SELECT * FROM brands WHERE id = ?').get(id);
+  if (!existing) return res.status(404).json({ error: 'Brand not found' });
+
+  const fields = ['name', 'priority', 'color', 'icon'];
+  const updates = [];
+  const values = [];
+
+  for (const field of fields) {
+    if (req.body[field] !== undefined) {
+      updates.push(`${field} = ?`);
+      values.push(req.body[field]);
+    }
+  }
+
+  if (updates.length === 0) return res.status(400).json({ error: 'No fields to update' });
+
+  values.push(id);
+  db.prepare(`UPDATE brands SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+
+  const brand = db.prepare('SELECT * FROM brands WHERE id = ?').get(id);
+  res.json(brand);
+});
+
+// ─── POSTS ──────────────────────────────────────────────────────
+
+app.get('/api/posts/stats', requireAuth, (req, res) => {
+  const stats = db.prepare(`
+    SELECT status, COUNT(*) as count FROM posts GROUP BY status
+  `).all();
+
+  const total = db.prepare('SELECT COUNT(*) as count FROM posts').get().count;
+
+  const result = { total };
+  for (const s of stats) {
+    result[s.status] = s.count;
+  }
+  res.json(result);
+});
+
+app.get('/api/posts', requireAuth, (req, res) => {
+  const { status, brand_id, assigned_to, platform } = req.query;
+  let sql = 'SELECT p.*, b.name as brand_name, t.name as assigned_name, c.name as campaign_name, u.name as creator_user_name FROM posts p LEFT JOIN brands b ON p.brand_id = b.id LEFT JOIN team_members t ON p.assigned_to = t.id LEFT JOIN campaigns c ON p.campaign_id = c.id LEFT JOIN users u ON p.created_by_user_id = u.id';
+  const conditions = [];
+  const values = [];
+
+  if (status) { conditions.push('p.status = ?'); values.push(status); }
+  if (brand_id) { conditions.push('p.brand_id = ?'); values.push(brand_id); }
+  if (assigned_to) { conditions.push('p.assigned_to = ?'); values.push(assigned_to); }
+  if (platform) { conditions.push('p.platform = ?'); values.push(platform); }
+  if (req.query.campaign_id) { conditions.push('p.campaign_id = ?'); values.push(req.query.campaign_id); }
+
+  // Visibility filtering: contributors only see their own posts or posts assigned to them
+  if (req.session.userRole === 'contributor') {
+    const currentUser = db.prepare('SELECT team_member_id FROM users WHERE id = ?').get(req.session.userId);
+    const teamMemberId = currentUser?.team_member_id;
+    if (teamMemberId) {
+      conditions.push('(p.created_by_user_id = ? OR p.assigned_to = ?)');
+      values.push(req.session.userId, teamMemberId);
+    } else {
+      conditions.push('p.created_by_user_id = ?');
+      values.push(req.session.userId);
+    }
+  }
+
+  if (conditions.length > 0) sql += ' WHERE ' + conditions.join(' AND ');
+  sql += ' ORDER BY p.updated_at DESC';
+
+  const posts = db.prepare(sql).all(...values);
+  
+  // Add thumbnail for each post
+  const postsWithThumbs = posts.map(p => {
+    const thumb = db.prepare("SELECT url, mime_type FROM post_attachments WHERE post_id = ? AND mime_type LIKE 'image/%' ORDER BY created_at ASC LIMIT 1").get(p.id);
+    return { 
+      ...p, 
+      platforms: JSON.parse(p.platforms || '[]'), 
+      publication_links: JSON.parse(p.publication_links || '[]'), 
+      thumbnail_url: thumb?.url || null 
+    };
+  });
+  
+  res.json(postsWithThumbs);
+});
+
+app.post('/api/posts', requireAuth, (req, res) => {
+  const { title, description, brand_id, assigned_to, status, platform, platforms, content_type, scheduled_date, notes, campaign_id } = req.body;
+  if (!title) return res.status(400).json({ error: 'Title is required' });
+
+  // Support both single platform and platforms array
+  const platformsArr = platforms || (platform ? [platform] : []);
+
+  const result = db.prepare(`
+    INSERT INTO posts (title, description, brand_id, assigned_to, status, platform, platforms, content_type, scheduled_date, notes, campaign_id, created_by_user_id)
+    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+  `).run(title, description || null, brand_id || null, assigned_to || null, status || 'draft', platformsArr[0] || null, JSON.stringify(platformsArr), content_type || null, scheduled_date || null, notes || null, campaign_id || null, req.session.userId);
+
+  const post = db.prepare('SELECT p.*, b.name as brand_name, t.name as assigned_name, c.name as campaign_name, u.name as creator_user_name FROM posts p LEFT JOIN brands b ON p.brand_id = b.id LEFT JOIN team_members t ON p.assigned_to = t.id LEFT JOIN campaigns c ON p.campaign_id = c.id LEFT JOIN users u ON p.created_by_user_id = u.id WHERE p.id = ?').get(result.lastInsertRowid);
+  res.status(201).json({ ...post, platforms: JSON.parse(post.platforms || '[]'), publication_links: JSON.parse(post.publication_links || '[]') });
+});
+
+app.patch('/api/posts/:id', requireAuth, requireOwnerOrRole('posts', 'superadmin', 'manager'), (req, res) => {
+  const { id } = req.params;
+  const existing = db.prepare('SELECT * FROM posts WHERE id = ?').get(id);
+  if (!existing) return res.status(404).json({ error: 'Post not found' });
+
+  const fields = ['title', 'description', 'brand_id', 'assigned_to', 'status', 'platform', 'content_type', 'scheduled_date', 'published_date', 'notes', 'campaign_id'];
+  const updates = ['updated_at = CURRENT_TIMESTAMP'];
+  const values = [];
+
+  for (const field of fields) {
+    if (req.body[field] !== undefined) {
+      updates.push(`${field} = ?`);
+      values.push(req.body[field]);
+    }
+  }
+  if (req.body.platforms !== undefined) {
+    updates.push('platforms = ?');
+    values.push(JSON.stringify(req.body.platforms));
+    // Also keep platform field in sync (first platform)
+    if (!req.body.platform) {
+      updates.push('platform = ?');
+      values.push(req.body.platforms[0] || null);
+    }
+  }
+  if (req.body.publication_links !== undefined) {
+    updates.push('publication_links = ?');
+    values.push(JSON.stringify(req.body.publication_links));
+  }
+
+  // Validate publication links when publishing
+  if (req.body.status === 'published') {
+    const currentPlatforms = req.body.platforms
+      ? req.body.platforms
+      : JSON.parse(existing.platforms || '[]');
+    const currentLinks = req.body.publication_links
+      ? req.body.publication_links
+      : JSON.parse(existing.publication_links || '[]');
+
+    if (currentPlatforms.length > 0) {
+      const missingPlatforms = currentPlatforms.filter(platform => {
+        const link = currentLinks.find(l => l.platform === platform);
+        return !link || !link.url || !link.url.trim();
+      });
+      if (missingPlatforms.length > 0) {
+        return res.status(400).json({
+          error: `Cannot publish: missing publication links for: ${missingPlatforms.join(', ')}`,
+          missingPlatforms
+        });
+      }
+    }
+  }
+
+  // Auto-set published_date when status changes to published
+  if (req.body.status === 'published' && !req.body.published_date) {
+    updates.push('published_date = CURRENT_TIMESTAMP');
+  }
+
+  values.push(id);
+  db.prepare(`UPDATE posts SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+
+  const post = db.prepare('SELECT p.*, b.name as brand_name, t.name as assigned_name, c.name as campaign_name, u.name as creator_user_name FROM posts p LEFT JOIN brands b ON p.brand_id = b.id LEFT JOIN team_members t ON p.assigned_to = t.id LEFT JOIN campaigns c ON p.campaign_id = c.id LEFT JOIN users u ON p.created_by_user_id = u.id WHERE p.id = ?').get(id);
+  res.json({ ...post, platforms: JSON.parse(post.platforms || '[]'), publication_links: JSON.parse(post.publication_links || '[]') });
+});
+
+app.delete('/api/posts/:id', requireAuth, requireOwnerOrRole('posts', 'superadmin', 'manager'), (req, res) => {
+  const result = db.prepare('DELETE FROM posts WHERE id = ?').run(req.params.id);
+  if (result.changes === 0) return res.status(404).json({ error: 'Post not found' });
+  res.json({ success: true });
+});
+
+// ─── POST ATTACHMENTS ───────────────────────────────────────────
+
+app.get('/api/posts/:id/attachments', requireAuth, (req, res) => {
+  const attachments = db.prepare('SELECT * FROM post_attachments WHERE post_id = ? ORDER BY created_at DESC').all(req.params.id);
+  res.json(attachments);
+});
+
+app.post('/api/posts/:id/attachments', requireAuth, upload.single('file'), (req, res) => {
+  if (!req.file) return res.status(400).json({ error: 'No file uploaded' });
+
+  const postId = req.params.id;
+  const post = db.prepare('SELECT * FROM posts WHERE id = ?').get(postId);
+  if (!post) return res.status(404).json({ error: 'Post not found' });
+
+  // Contributors can only add to their own posts
+  if (req.session.userRole === 'contributor' && post.created_by_user_id !== req.session.userId) {
+    // Also check if assigned to them
+    const currentUser = db.prepare('SELECT team_member_id FROM users WHERE id = ?').get(req.session.userId);
+    if (!currentUser?.team_member_id || post.assigned_to !== currentUser.team_member_id) {
+      fs.unlinkSync(path.join(uploadsDir, req.file.filename));
+      return res.status(403).json({ error: 'You can only manage attachments on your own posts' });
+    }
+  }
+
+  const url = `/api/uploads/${req.file.filename}`;
+  const result = db.prepare(`
+    INSERT INTO post_attachments (post_id, filename, original_name, mime_type, size, url)
+    VALUES (?, ?, ?, ?, ?, ?)
+  `).run(postId, req.file.filename, req.file.originalname, req.file.mimetype, req.file.size, url);
+
+  const attachment = db.prepare('SELECT * FROM post_attachments WHERE id = ?').get(result.lastInsertRowid);
+  res.status(201).json(attachment);
+});
+
+app.delete('/api/attachments/:id', requireAuth, (req, res) => {
+  const attachment = db.prepare('SELECT pa.*, p.created_by_user_id, p.assigned_to FROM post_attachments pa JOIN posts p ON pa.post_id = p.id WHERE pa.id = ?').get(req.params.id);
+  if (!attachment) return res.status(404).json({ error: 'Attachment not found' });
+
+  // Contributors can only delete from their own posts
+  if (req.session.userRole === 'contributor' && attachment.created_by_user_id !== req.session.userId) {
+    const currentUser = db.prepare('SELECT team_member_id FROM users WHERE id = ?').get(req.session.userId);
+    if (!currentUser?.team_member_id || attachment.assigned_to !== currentUser.team_member_id) {
+      return res.status(403).json({ error: 'You can only manage attachments on your own posts' });
+    }
+  }
+
+  // Delete file from disk
+  const filePath = path.join(uploadsDir, attachment.filename);
+  if (fs.existsSync(filePath)) {
+    fs.unlinkSync(filePath);
+  }
+
+  db.prepare('DELETE FROM post_attachments WHERE id = ?').run(req.params.id);
+  res.json({ success: true });
+});
+
+// ─── ASSETS ─────────────────────────────────────────────────────
+
+app.get('/api/assets', requireAuth, (req, res) => {
+  const { brand_id, campaign_id, folder, tags } = req.query;
+  let sql = 'SELECT a.*, b.name as brand_name, c.name as campaign_name, t.name as uploader_name FROM assets a LEFT JOIN brands b ON a.brand_id = b.id LEFT JOIN campaigns c ON a.campaign_id = c.id LEFT JOIN team_members t ON a.uploaded_by = t.id';
+  const conditions = [];
+  const values = [];
+
+  if (brand_id) { conditions.push('a.brand_id = ?'); values.push(brand_id); }
+  if (campaign_id) { conditions.push('a.campaign_id = ?'); values.push(campaign_id); }
+  if (folder) { conditions.push('a.folder = ?'); values.push(folder); }
+  if (tags) { conditions.push('a.tags LIKE ?'); values.push(`%${tags}%`); }
+
+  if (conditions.length > 0) sql += ' WHERE ' + conditions.join(' AND ');
+  sql += ' ORDER BY a.created_at DESC';
+
+  const assets = db.prepare(sql).all(...values);
+  res.json(assets.map(a => ({ ...a, tags: JSON.parse(a.tags || '[]') })));
+});
+
+app.post('/api/assets/upload', requireAuth, upload.single('file'), (req, res) => {
+  if (!req.file) return res.status(400).json({ error: 'No file uploaded' });
+
+  const { brand_id, campaign_id, uploaded_by, folder, tags } = req.body;
+
+  const result = db.prepare(`
+    INSERT INTO assets (filename, original_name, mime_type, size, tags, brand_id, campaign_id, uploaded_by, folder)
+    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
+  `).run(
+    req.file.filename,
+    req.file.originalname,
+    req.file.mimetype,
+    req.file.size,
+    tags || '[]',
+    brand_id || null,
+    campaign_id || null,
+    uploaded_by || null,
+    folder || 'general'
+  );
+
+  const asset = db.prepare('SELECT * FROM assets WHERE id = ?').get(result.lastInsertRowid);
+  res.status(201).json({ ...asset, tags: JSON.parse(asset.tags || '[]') });
+});
+
+app.delete('/api/assets/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const asset = db.prepare('SELECT * FROM assets WHERE id = ?').get(req.params.id);
+  if (!asset) return res.status(404).json({ error: 'Asset not found' });
+
+  // Delete file from disk
+  const filePath = path.join(uploadsDir, asset.filename);
+  if (fs.existsSync(filePath)) {
+    fs.unlinkSync(filePath);
+  }
+
+  db.prepare('DELETE FROM assets WHERE id = ?').run(req.params.id);
+  res.json({ success: true });
+});
+
+// ─── CAMPAIGNS ──────────────────────────────────────────────────
+
+app.get('/api/campaigns', requireAuth, (req, res) => {
+  const { brand_id, status, start_date, end_date } = req.query;
+  let sql = 'SELECT c.*, b.name as brand_name FROM campaigns c LEFT JOIN brands b ON c.brand_id = b.id';
+  const conditions = [];
+  const values = [];
+
+  if (brand_id) { conditions.push('c.brand_id = ?'); values.push(brand_id); }
+  if (status) { conditions.push('c.status = ?'); values.push(status); }
+  if (start_date) { conditions.push('c.end_date >= ?'); values.push(start_date); }
+  if (end_date) { conditions.push('c.start_date <= ?'); values.push(end_date); }
+
+  if (conditions.length > 0) sql += ' WHERE ' + conditions.join(' AND ');
+  sql += ' ORDER BY c.start_date DESC';
+
+  const campaigns = db.prepare(sql).all(...values);
+  res.json(campaigns.map(c => ({ ...c, platforms: JSON.parse(c.platforms || '[]') })));
+});
+
+app.post('/api/campaigns', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { name, description, brand_id, start_date, end_date, status, color, budget, goals, platforms } = req.body;
+  if (!name) return res.status(400).json({ error: 'Name is required' });
+  if (!start_date || !end_date) return res.status(400).json({ error: 'Start and end dates are required' });
+
+  const result = db.prepare(`
+    INSERT INTO campaigns (name, description, brand_id, start_date, end_date, status, color, budget, goals, platforms, created_by_user_id)
+    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+  `).run(name, description || null, brand_id || null, start_date, end_date, status || 'planning', color || null, budget || null, goals || null, JSON.stringify(platforms || []), req.session.userId);
+
+  const campaign = db.prepare('SELECT c.*, b.name as brand_name FROM campaigns c LEFT JOIN brands b ON c.brand_id = b.id WHERE c.id = ?').get(result.lastInsertRowid);
+  res.status(201).json({ ...campaign, platforms: JSON.parse(campaign.platforms || '[]') });
+});
+
+app.patch('/api/campaigns/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { id } = req.params;
+  const existing = db.prepare('SELECT * FROM campaigns WHERE id = ?').get(id);
+  if (!existing) return res.status(404).json({ error: 'Campaign not found' });
+
+  const fields = ['name', 'description', 'brand_id', 'start_date', 'end_date', 'status', 'color', 'budget', 'goals',
+    'budget_spent', 'revenue', 'impressions', 'clicks', 'conversions', 'cost_per_click', 'notes'];
+  const updates = [];
+  const values = [];
+
+  for (const field of fields) {
+    if (req.body[field] !== undefined) {
+      updates.push(`${field} = ?`);
+      values.push(req.body[field]);
+    }
+  }
+  if (req.body.platforms !== undefined) {
+    updates.push('platforms = ?');
+    values.push(JSON.stringify(req.body.platforms));
+  }
+
+  if (updates.length === 0) return res.status(400).json({ error: 'No fields to update' });
+
+  values.push(id);
+  db.prepare(`UPDATE campaigns SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+
+  const campaign = db.prepare('SELECT c.*, b.name as brand_name FROM campaigns c LEFT JOIN brands b ON c.brand_id = b.id WHERE c.id = ?').get(id);
+  res.json({ ...campaign, platforms: JSON.parse(campaign.platforms || '[]') });
+});
+
+app.delete('/api/campaigns/:id', requireAuth, requireRole('superadmin', 'manager'), async (req, res) => {
+  const { id } = req.params;
+  
+  try {
+    // Delete associated posts first (cascade)
+    db.prepare('DELETE FROM posts WHERE campaign_id = ?').run(id);
+    
+    // Delete campaign tracks
+    db.prepare('DELETE FROM campaign_tracks WHERE campaign_id = ?').run(id);
+    
+    // Unlink assets (set campaign_id to null instead of deleting the files)
+    db.prepare('UPDATE assets SET campaign_id = NULL WHERE campaign_id = ?').run(id);
+    
+    // Delete the campaign
+    const result = db.prepare('DELETE FROM campaigns WHERE id = ?').run(id);
+    if (result.changes === 0) return res.status(404).json({ error: 'Campaign not found' });
+    
+    res.json({ success: true });
+  } catch (err) {
+    console.error('Delete campaign error:', err);
+    res.status(500).json({ error: 'Failed to delete campaign' });
+  }
+});
+
+// ─── BUDGET ENTRIES ─────────────────────────────────────────────
+
+app.get('/api/budget', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const entries = db.prepare(`
+    SELECT be.*, c.name as campaign_name
+    FROM budget_entries be
+    LEFT JOIN campaigns c ON be.campaign_id = c.id
+    ORDER BY be.date_received DESC
+  `).all();
+  res.json(entries);
+});
+
+app.post('/api/budget', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { label, amount, source, campaign_id, category, date_received, notes } = req.body;
+  if (!label || !amount || !date_received) return res.status(400).json({ error: 'Label, amount, and date are required' });
+
+  const result = db.prepare(`
+    INSERT INTO budget_entries (label, amount, source, campaign_id, category, date_received, notes)
+    VALUES (?, ?, ?, ?, ?, ?, ?)
+  `).run(label, amount, source || null, campaign_id || null, category || 'marketing', date_received, notes || '');
+
+  const entry = db.prepare('SELECT be.*, c.name as campaign_name FROM budget_entries be LEFT JOIN campaigns c ON be.campaign_id = c.id WHERE be.id = ?').get(result.lastInsertRowid);
+  res.status(201).json(entry);
+});
+
+app.patch('/api/budget/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const existing = db.prepare('SELECT * FROM budget_entries WHERE id = ?').get(req.params.id);
+  if (!existing) return res.status(404).json({ error: 'Budget entry not found' });
+
+  const fields = ['label', 'amount', 'source', 'campaign_id', 'category', 'date_received', 'notes'];
+  const updates = [];
+  const values = [];
+
+  for (const field of fields) {
+    if (req.body[field] !== undefined) {
+      updates.push(`${field} = ?`);
+      values.push(req.body[field]);
+    }
+  }
+
+  if (updates.length === 0) return res.status(400).json({ error: 'No fields to update' });
+  values.push(req.params.id);
+  db.prepare(`UPDATE budget_entries SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+
+  const entry = db.prepare('SELECT be.*, c.name as campaign_name FROM budget_entries be LEFT JOIN campaigns c ON be.campaign_id = c.id WHERE be.id = ?').get(req.params.id);
+  res.json(entry);
+});
+
+app.delete('/api/budget/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const result = db.prepare('DELETE FROM budget_entries WHERE id = ?').run(req.params.id);
+  if (result.changes === 0) return res.status(404).json({ error: 'Entry not found' });
+  res.json({ success: true });
+});
+
+// Finance summary — aggregates across all campaigns & tracks
+app.get('/api/finance/summary', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const totalReceived = db.prepare('SELECT COALESCE(SUM(amount), 0) as total FROM budget_entries').get().total;
+
+  const campaignStats = db.prepare(`
+    SELECT
+      c.id, c.name, c.budget, c.status,
+      COALESCE(SUM(ct.budget_allocated), 0) as tracks_allocated,
+      COALESCE(SUM(ct.budget_spent), 0) as tracks_spent,
+      COALESCE(SUM(ct.revenue), 0) as tracks_revenue,
+      COALESCE(SUM(ct.impressions), 0) as tracks_impressions,
+      COALESCE(SUM(ct.clicks), 0) as tracks_clicks,
+      COALESCE(SUM(ct.conversions), 0) as tracks_conversions
+    FROM campaigns c
+    LEFT JOIN campaign_tracks ct ON ct.campaign_id = c.id
+    GROUP BY c.id
+    ORDER BY c.start_date DESC
+  `).all();
+
+  const totals = campaignStats.reduce((acc, c) => ({
+    allocated: acc.allocated + c.tracks_allocated,
+    spent: acc.spent + c.tracks_spent,
+    revenue: acc.revenue + c.tracks_revenue,
+    impressions: acc.impressions + c.tracks_impressions,
+    clicks: acc.clicks + c.tracks_clicks,
+    conversions: acc.conversions + c.tracks_conversions,
+  }), { allocated: 0, spent: 0, revenue: 0, impressions: 0, clicks: 0, conversions: 0 });
+
+  res.json({
+    totalReceived,
+    ...totals,
+    remaining: totalReceived - totals.spent,
+    roi: totals.spent > 0 ? ((totals.revenue - totals.spent) / totals.spent * 100) : 0,
+    campaigns: campaignStats,
+  });
+});
+
+// ─── CAMPAIGN TRACKS ────────────────────────────────────────────
+
+app.get('/api/campaigns/:id/tracks', requireAuth, (req, res) => {
+  const tracks = db.prepare('SELECT * FROM campaign_tracks WHERE campaign_id = ? ORDER BY created_at').all(req.params.id);
+  res.json(tracks);
+});
+
+app.post('/api/campaigns/:id/tracks', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { name, type, platform, budget_allocated, status, notes } = req.body;
+  const campaign = db.prepare('SELECT id FROM campaigns WHERE id = ?').get(req.params.id);
+  if (!campaign) return res.status(404).json({ error: 'Campaign not found' });
+
+  const result = db.prepare(`
+    INSERT INTO campaign_tracks (campaign_id, name, type, platform, budget_allocated, status, notes)
+    VALUES (?, ?, ?, ?, ?, ?, ?)
+  `).run(req.params.id, name || null, type || 'organic_social', platform || null, budget_allocated || 0, status || 'planned', notes || '');
+
+  const track = db.prepare('SELECT * FROM campaign_tracks WHERE id = ?').get(result.lastInsertRowid);
+  res.status(201).json(track);
+});
+
+app.patch('/api/tracks/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const existing = db.prepare('SELECT * FROM campaign_tracks WHERE id = ?').get(req.params.id);
+  if (!existing) return res.status(404).json({ error: 'Track not found' });
+
+  const fields = ['name', 'type', 'platform', 'budget_allocated', 'budget_spent', 'revenue',
+    'impressions', 'clicks', 'conversions', 'notes', 'status'];
+  const updates = [];
+  const values = [];
+
+  for (const field of fields) {
+    if (req.body[field] !== undefined) {
+      updates.push(`${field} = ?`);
+      values.push(req.body[field]);
+    }
+  }
+
+  if (updates.length === 0) return res.status(400).json({ error: 'No fields to update' });
+
+  values.push(req.params.id);
+  db.prepare(`UPDATE campaign_tracks SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+
+  const track = db.prepare('SELECT * FROM campaign_tracks WHERE id = ?').get(req.params.id);
+  res.json(track);
+});
+
+app.delete('/api/tracks/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const result = db.prepare('DELETE FROM campaign_tracks WHERE id = ?').run(req.params.id);
+  if (result.changes === 0) return res.status(404).json({ error: 'Track not found' });
+  res.json({ success: true });
+});
+
+// Get posts linked to a campaign (across all tracks)
+app.get('/api/campaigns/:id/posts', requireAuth, (req, res) => {
+  const posts = db.prepare(`
+    SELECT p.*, t.name as assigned_name, b.name as brand_name, ct.name as track_name, ct.type as track_type
+    FROM posts p
+    LEFT JOIN team_members t ON p.assigned_to = t.id
+    LEFT JOIN brands b ON p.brand_id = b.id
+    LEFT JOIN campaign_tracks ct ON p.track_id = ct.id
+    WHERE p.campaign_id = ?
+    ORDER BY p.created_at DESC
+  `).all(req.params.id);
+  res.json(posts.map(p => ({ ...p, platforms: JSON.parse(p.platforms || '[]'), publication_links: JSON.parse(p.publication_links || '[]') })));
+});
+
+// ─── PROJECTS ───────────────────────────────────────────────────
+
+app.get('/api/projects', requireAuth, (req, res) => {
+  const { brand_id, owner_id, status } = req.query;
+  let sql = 'SELECT p.*, b.name as brand_name, t.name as owner_name FROM projects p LEFT JOIN brands b ON p.brand_id = b.id LEFT JOIN team_members t ON p.owner_id = t.id';
+  const conditions = [];
+  const values = [];
+
+  if (brand_id) { conditions.push('p.brand_id = ?'); values.push(brand_id); }
+  if (owner_id) { conditions.push('p.owner_id = ?'); values.push(owner_id); }
+  if (status) { conditions.push('p.status = ?'); values.push(status); }
+
+  if (conditions.length > 0) sql += ' WHERE ' + conditions.join(' AND ');
+  sql += ' ORDER BY p.created_at DESC';
+
+  res.json(db.prepare(sql).all(...values));
+});
+
+app.get('/api/projects/:id', requireAuth, (req, res) => {
+  const project = db.prepare('SELECT p.*, b.name as brand_name, t.name as owner_name FROM projects p LEFT JOIN brands b ON p.brand_id = b.id LEFT JOIN team_members t ON p.owner_id = t.id WHERE p.id = ?').get(req.params.id);
+  if (!project) return res.status(404).json({ error: 'Project not found' });
+  res.json(project);
+});
+
+app.post('/api/projects', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { name, description, brand_id, owner_id, status, priority, due_date } = req.body;
+  if (!name) return res.status(400).json({ error: 'Name is required' });
+
+  const result = db.prepare(`
+    INSERT INTO projects (name, description, brand_id, owner_id, status, priority, due_date, created_by_user_id)
+    VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+  `).run(name, description || null, brand_id || null, owner_id || null, status || 'active', priority || 'medium', due_date || null, req.session.userId);
+
+  const project = db.prepare('SELECT p.*, b.name as brand_name, t.name as owner_name FROM projects p LEFT JOIN brands b ON p.brand_id = b.id LEFT JOIN team_members t ON p.owner_id = t.id WHERE p.id = ?').get(result.lastInsertRowid);
+  res.status(201).json(project);
+});
+
+app.patch('/api/projects/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const { id } = req.params;
+  const existing = db.prepare('SELECT * FROM projects WHERE id = ?').get(id);
+  if (!existing) return res.status(404).json({ error: 'Project not found' });
+
+  const fields = ['name', 'description', 'brand_id', 'owner_id', 'status', 'priority', 'due_date'];
+  const updates = [];
+  const values = [];
+
+  for (const field of fields) {
+    if (req.body[field] !== undefined) {
+      updates.push(`${field} = ?`);
+      values.push(req.body[field]);
+    }
+  }
+
+  if (updates.length === 0) return res.status(400).json({ error: 'No fields to update' });
+
+  values.push(id);
+  db.prepare(`UPDATE projects SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+
+  const project = db.prepare('SELECT p.*, b.name as brand_name, t.name as owner_name FROM projects p LEFT JOIN brands b ON p.brand_id = b.id LEFT JOIN team_members t ON p.owner_id = t.id WHERE p.id = ?').get(id);
+  res.json(project);
+});
+
+app.delete('/api/projects/:id', requireAuth, requireRole('superadmin', 'manager'), (req, res) => {
+  const result = db.prepare('DELETE FROM projects WHERE id = ?').run(req.params.id);
+  if (result.changes === 0) return res.status(404).json({ error: 'Project not found' });
+  res.json({ success: true });
+});
+
+// ─── TASKS ──────────────────────────────────────────────────────
+
+app.get('/api/tasks', requireAuth, (req, res) => {
+  const { project_id, assigned_to, status, is_personal } = req.query;
+  let sql = `SELECT t.*, 
+    p.name as project_name, 
+    a.name as assigned_name, 
+    c.name as creator_name,
+    u.name as creator_user_name
+    FROM tasks t 
+    LEFT JOIN projects p ON t.project_id = p.id 
+    LEFT JOIN team_members a ON t.assigned_to = a.id 
+    LEFT JOIN team_members c ON t.created_by = c.id
+    LEFT JOIN users u ON t.created_by_user_id = u.id`;
+  const conditions = [];
+  const values = [];
+
+  if (project_id) { conditions.push('t.project_id = ?'); values.push(project_id); }
+  if (assigned_to) { conditions.push('t.assigned_to = ?'); values.push(assigned_to); }
+  if (status) { conditions.push('t.status = ?'); values.push(status); }
+  if (is_personal !== undefined) { conditions.push('t.is_personal = ?'); values.push(is_personal === 'true' || is_personal === '1' ? 1 : 0); }
+
+  // Visibility filtering: non-superadmins only see tasks they created or are assigned to
+  if (req.session.userRole !== 'superadmin') {
+    const currentUser = db.prepare('SELECT team_member_id FROM users WHERE id = ?').get(req.session.userId);
+    const teamMemberId = currentUser?.team_member_id;
+    if (teamMemberId) {
+      conditions.push('(t.created_by_user_id = ? OR t.assigned_to = ?)');
+      values.push(req.session.userId, teamMemberId);
+    } else {
+      conditions.push('t.created_by_user_id = ?');
+      values.push(req.session.userId);
+    }
+  }
+
+  if (conditions.length > 0) sql += ' WHERE ' + conditions.join(' AND ');
+  sql += ' ORDER BY t.created_at DESC';
+
+  res.json(db.prepare(sql).all(...values));
+});
+
+app.get('/api/tasks/my/:memberId', requireAuth, (req, res) => {
+  const tasks = db.prepare(`
+    SELECT t.*, p.name as project_name, u.name as creator_user_name
+    FROM tasks t 
+    LEFT JOIN projects p ON t.project_id = p.id
+    LEFT JOIN users u ON t.created_by_user_id = u.id
+    WHERE t.assigned_to = ? AND t.is_personal = 1
+    ORDER BY t.due_date ASC, t.priority DESC
+  `).all(req.params.memberId);
+  res.json(tasks);
+});
+
+app.post('/api/tasks', requireAuth, (req, res) => {
+  const { title, description, project_id, assigned_to, created_by, status, priority, due_date, is_personal } = req.body;
+  if (!title) return res.status(400).json({ error: 'Title is required' });
+
+  const result = db.prepare(`
+    INSERT INTO tasks (title, description, project_id, assigned_to, created_by, status, priority, due_date, is_personal, created_by_user_id)
+    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+  `).run(title, description || null, project_id || null, assigned_to || null, created_by || null, status || 'todo', priority || 'medium', due_date || null, is_personal ? 1 : 0, req.session.userId);
+
+  const task = db.prepare(`SELECT t.*, p.name as project_name, a.name as assigned_name, c.name as creator_name, u.name as creator_user_name
+    FROM tasks t LEFT JOIN projects p ON t.project_id = p.id LEFT JOIN team_members a ON t.assigned_to = a.id LEFT JOIN team_members c ON t.created_by = c.id LEFT JOIN users u ON t.created_by_user_id = u.id WHERE t.id = ?`).get(result.lastInsertRowid);
+  res.status(201).json(task);
+});
+
+app.patch('/api/tasks/:id', requireAuth, requireOwnerOrRole('tasks', 'superadmin', 'manager'), (req, res) => {
+  const { id } = req.params;
+  const existing = db.prepare('SELECT * FROM tasks WHERE id = ?').get(id);
+  if (!existing) return res.status(404).json({ error: 'Task not found' });
+
+  const fields = ['title', 'description', 'project_id', 'assigned_to', 'created_by', 'status', 'priority', 'due_date', 'is_personal'];
+  const updates = [];
+  const values = [];
+
+  for (const field of fields) {
+    if (req.body[field] !== undefined) {
+      updates.push(`${field} = ?`);
+      values.push(field === 'is_personal' ? (req.body[field] ? 1 : 0) : req.body[field]);
+    }
+  }
+
+  // Auto-set completed_at when status changes to done
+  if (req.body.status === 'done' && existing.status !== 'done') {
+    updates.push('completed_at = CURRENT_TIMESTAMP');
+  } else if (req.body.status && req.body.status !== 'done' && existing.status === 'done') {
+    updates.push('completed_at = NULL');
+  }
+
+  if (updates.length === 0) return res.status(400).json({ error: 'No fields to update' });
+
+  values.push(id);
+  db.prepare(`UPDATE tasks SET ${updates.join(', ')} WHERE id = ?`).run(...values);
+
+  const task = db.prepare(`SELECT t.*, p.name as project_name, a.name as assigned_name, c.name as creator_name, u.name as creator_user_name
+    FROM tasks t LEFT JOIN projects p ON t.project_id = p.id LEFT JOIN team_members a ON t.assigned_to = a.id LEFT JOIN team_members c ON t.created_by = c.id LEFT JOIN users u ON t.created_by_user_id = u.id WHERE t.id = ?`).get(id);
+  res.json(task);
+});
+
+app.delete('/api/tasks/:id', requireAuth, requireOwnerOrRole('tasks', 'superadmin', 'manager'), (req, res) => {
+  const result = db.prepare('DELETE FROM tasks WHERE id = ?').run(req.params.id);
+  if (result.changes === 0) return res.status(404).json({ error: 'Task not found' });
+  res.json({ success: true });
+});
+
+// ─── DASHBOARD ──────────────────────────────────────────────────
+
+app.get('/api/dashboard', requireAuth, (req, res) => {
+  // Post counts by status
+  const postsByStatus = db.prepare('SELECT status, COUNT(*) as count FROM posts GROUP BY status').all();
+  const totalPosts = db.prepare('SELECT COUNT(*) as count FROM posts').get().count;
+
+  // Active campaigns
+  const activeCampaigns = db.prepare("SELECT COUNT(*) as count FROM campaigns WHERE status = 'active'").get().count;
+  const totalCampaigns = db.prepare('SELECT COUNT(*) as count FROM campaigns').get().count;
+
+  // Overdue tasks
+  const overdueTasks = db.prepare(`
+    SELECT COUNT(*) as count FROM tasks 
+    WHERE due_date < date('now') AND status != 'done'
+  `).get().count;
+
+  // Total tasks by status
+  const tasksByStatus = db.prepare('SELECT status, COUNT(*) as count FROM tasks GROUP BY status').all();
+
+  // Team workload (tasks assigned per member)
+  const teamWorkload = db.prepare(`
+    SELECT t.id, t.name, t.role,
+      COUNT(CASE WHEN tk.status != 'done' THEN 1 END) as active_tasks,
+      COUNT(CASE WHEN tk.status = 'done' THEN 1 END) as completed_tasks,
+      COUNT(CASE WHEN p.status NOT IN ('published', 'rejected') THEN 1 END) as active_posts
+    FROM team_members t
+    LEFT JOIN tasks tk ON tk.assigned_to = t.id
+    LEFT JOIN posts p ON p.assigned_to = t.id
+    GROUP BY t.id
+    ORDER BY active_tasks DESC
+  `).all();
+
+  // Active projects
+  const activeProjects = db.prepare("SELECT COUNT(*) as count FROM projects WHERE status = 'active'").get().count;
+
+  // Recent posts
+  const recentPosts = db.prepare(`
+    SELECT p.*, b.name as brand_name, t.name as assigned_name
+    FROM posts p 
+    LEFT JOIN brands b ON p.brand_id = b.id 
+    LEFT JOIN team_members t ON p.assigned_to = t.id
+    ORDER BY p.updated_at DESC LIMIT 5
+  `).all();
+
+  // Upcoming campaigns
+  const upcomingCampaigns = db.prepare(`
+    SELECT c.*, b.name as brand_name 
+    FROM campaigns c 
+    LEFT JOIN brands b ON c.brand_id = b.id
+    WHERE c.end_date >= date('now')
+    ORDER BY c.start_date ASC LIMIT 5
+  `).all();
+
+  res.json({
+    posts: {
+      total: totalPosts,
+      byStatus: postsByStatus.reduce((acc, s) => { acc[s.status] = s.count; return acc; }, {})
+    },
+    campaigns: {
+      total: totalCampaigns,
+      active: activeCampaigns
+    },
+    tasks: {
+      overdue: overdueTasks,
+      byStatus: tasksByStatus.reduce((acc, s) => { acc[s.status] = s.count; return acc; }, {})
+    },
+    projects: {
+      active: activeProjects
+    },
+    teamWorkload,
+    recentPosts,
+    upcomingCampaigns
+  });
+});
+
+// ─── ERROR HANDLING ─────────────────────────────────────────────
+
+// Global Express error handler
+app.use((err, req, res, next) => {
+  console.error(`[ERROR] ${req.method} ${req.path}:`, err.message);
+  res.status(500).json({ error: 'Internal server error', details: err.message });
+});
+
+// Prevent process crash on unhandled errors
+process.on('uncaughtException', (err) => {
+  console.error('[UNCAUGHT]', err.message);
+});
+process.on('unhandledRejection', (err) => {
+  console.error('[UNHANDLED REJECTION]', err);
+});
+
+// ─── START SERVER ───────────────────────────────────────────────
+
+app.listen(PORT, () => {
+  console.log(`🚀 Marketing App API running on http://localhost:${PORT}`);
+  console.log(`📁 Uploads directory: ${uploadsDir}`);
+});
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